New open and hidden charm spectroscopy
29--拉曼光谱在石墨烯结构表征中的应用
* E-mail: jinzhang@ Received September 6, 2013; published November 3, 2013. Project supported by the National Natural Science Foundation of China (Nos. 21233001, 21129001, 51272006 and 51121091) and the Ministry of Science and Technology of the People’s Republic of China (No. 2011YQ0301240201 and 2011CB932601). 项目受国家自然科学基金(Nos. 21233001, 21129001, 51272006 和 51121091)和科技部项目(Nos. 2011YQ0301240201 和 2011CB932601)资助.
量的研究表明扭转的双层石墨烯由于层间耦合较弱其而当扭转角小于15左右时这个线性的色散关系会被破坏能带结构会变为抛物线型5a给出了单层石墨烯及其折叠区域即扭转的双层石墨烯的拉曼谱图在5145nm激光激发下折叠区域的g峰半峰宽较单层石墨烯更小频率向高波数位移当激光波长减小至488nm两者差异几乎消失了这是由于扭转的双层石墨烯层间耦合较弱其电子色散曲线并未发生裂分g峰仍表现为单个的洛伦兹峰型82如图5b所示与扭转的双层石墨烯类似少层石墨烯经折叠之后拉曼光谱仍然保持了未折叠区域的光谱特征41大多数扭转的双层石墨烯的拉曼光谱仍然保持了单层石墨烯的拉曼特征g峰表现为单个的洛伦兹峰型且其强度大于g但对于某些扭转角在某一特定波长的激光激发下峰强度会极大地增强其强度会达到单层石墨烯的数十倍388384图5c为633nm激光激发下单层石墨烯和扭转角为31027的双层石与单层石墨烯相比扭转的双层石墨cm1强度对角度有着较强的依赖性峰强度在扭转角为10左右时达到最大aba和abc堆垛的三层石墨烯的ag峰拉曼光谱5173插图为aramanspectraabcstackedtrilayergraphene5173insetsramanimagesbandrespectively综述actachim
L-阿拉伯糖指纹区太赫兹光谱和拉曼光谱的研究
L-阿拉伯糖指纹区太赫兹光谱和拉曼光谱的研究苏同福;王长青;赵国忠;樊素芳;杨国玉;徐翠莲;苏惠【摘要】为了解生物体内L-阿拉伯糖在代谢过程中的合成与降解机制,采用太赫兹和拉曼光谱系统,对其指纹区的振动进行检测.结果表明,L-阿拉伯糖太赫兹图谱在频率49.5和72.2 cm-1分别检测出了振动吸收,其中72.2 cm-1的振动为首次检出.该振动频率与其折射率图谱反常色散的频率基本一致,故这两个振动吸收可以作为L-阿拉伯糖的特征吸收.最为重要的是,在该频域内,检测得到图谱的波型与三种异构体理论值简单叠加后波型极为相似,故可以初步判定样品含有三种构象异构体(α-型、β-型和l-型结构),非单一组分,而是混合组分;对于拉曼图谱而言,其特点简洁而明晰,一般将指纹区的振动,从高到低分为四个区域:吡喃环结构的伸缩振动、亚甲基的摇摆振动、环上羟基的扭曲振动及环骨架扭曲和畸变振动.同时也根据密度泛函理论B3LYP/6-311G**基组,分别对L-阿拉伯糖的三种构象异构体的振动进行模拟计算,利用势能分布对这些振动进行归属和指认.与理论值相比,振动频率检测值有不同程度的红移,即振动频率向低频发生了偏移,其原因是样品内不同分子间相互影响所致.【期刊名称】《光谱学与光谱分析》【年(卷),期】2018(038)009【总页数】7页(P2713-2719)【关键词】L-阿拉伯糖;太赫兹图谱;特征振动;拉曼图谱;归属【作者】苏同福;王长青;赵国忠;樊素芳;杨国玉;徐翠莲;苏惠【作者单位】河南农业大学化学系 ,河南郑州 450002;河南农业大学化学系 ,河南郑州 450002;首都师范大学物理系 ,北京市成像技术高精尖创新中心 ,太赫兹光电子学教育部重点实验室 ,北京 100048;河南农业大学化学系 ,河南郑州 450002;河南农业大学化学系 ,河南郑州 450002;河南农业大学化学系 ,河南郑州 450002;河南农业大学化学系 ,河南郑州 450002【正文语种】中文【中图分类】O657.6引言L-阿拉伯糖是一种五碳糖，是组成糖链如半纤维素等的基本结构单元之一[1]，天然存在的阿拉伯糖以L型的为主，也是食品中常见的甜味剂。
具有复杂光谱特征的丙烯气体的TDLAS检测技术研究
去除解调光谱的直流偏置，采用多元回归模型降低化工过程的背景气体光谱干扰。在模拟实际环境的气体实验中，该装
置在 0~1% 量程内的最大相对误差为 0.55%。对 0.2% 的丙烯进行 3 小时连续测量，标准差为 9.3×10−6；Allen 方差分析
发现在积分时间为 221.9 s 时，极限标准差可达 1.33×10−6。在抗干扰测试中，当背景气体甲烷、乙烯的浓度变化时，丙烯
具有复杂光谱特征的丙烯气体的TDLAS检测技术研究 钟笠 宋迪 焦月 李晗 李国林 季文海 TDLAS detection of propylene with complex spectral features ZHONG Li, SONG Di, JIAO Yue, LI Han, LI Guo-lin, JI Wen-hai
的测量误差最大仅为 19.17×10−6。调制吸收光谱技术克服了色谱和软测量等传统方法的不足，TDLAS 装置可检测有复
杂光谱特征的重烃分子，展示了测量精度高、稳定性好、抗背景光谱干扰能力强等优点。
关 键 词：可调谐二极管激光吸收光谱；丙烯测量；过程分析；多元线性回归
中图分类号：O433.1
文献标志码：A
doi：10.37188/CO.2019-0203
TDLAS detection of propylene with complex spectral features
ZHONG Li，SONG Di，JIAO Yue，LI Han，LI Guo-lin*，JI Wen-hai* （College of Information and Control Engineering, China University of Petroleum, Qingdao 266580, China）
稳定的高功率激光系统在高级引力波探测器中的应用
Stabilized high-power laser system forthe gravitational wave detector advancedLIGOP.Kwee,1,∗C.Bogan,2K.Danzmann,1,2M.Frede,4H.Kim,1P.King,5J.P¨o ld,1O.Puncken,3R.L.Savage,5F.Seifert,5P.Wessels,3L.Winkelmann,3and B.Willke21Max-Planck-Institut f¨u r Gravitationsphysik(Albert-Einstein-Institut),Hannover,Germany2Leibniz Universit¨a t Hannover,Hannover,Germany3Laser Zentrum Hannover e.V.,Hannover,Germany4neoLASE GmbH,Hannover,Germany5LIGO Laboratory,California Institute of Technology,Pasadena,California,USA*patrick.kwee@aei.mpg.deAbstract:An ultra-stable,high-power cw Nd:Y AG laser system,devel-oped for the ground-based gravitational wave detector Advanced LIGO(Laser Interferometer Gravitational-Wave Observatory),was comprehen-sively ser power,frequency,beam pointing and beamquality were simultaneously stabilized using different active and passiveschemes.The output beam,the performance of the stabilization,and thecross-coupling between different stabilization feedback control loops werecharacterized and found to fulfill most design requirements.The employedstabilization schemes and the achieved performance are of relevance tomany high-precision optical experiments.©2012Optical Society of AmericaOCIS codes:(140.3425)Laser stabilization;(120.3180)Interferometry.References and links1.S.Rowan and J.Hough,“Gravitational wave detection by interferometry(ground and space),”Living Rev.Rel-ativity3,1–3(2000).2.P.R.Saulson,Fundamentals of Interferometric Gravitational Wave Detectors(World Scientific,1994).3.G.M.Harry,“Advanced LIGO:the next generation of gravitational wave detectors,”Class.Quantum Grav.27,084006(2010).4. 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B.Willke,N.Uehara,E.K.Gustafson,R.L.Byer,P.J.King,S.U.Seel,and R.L.Savage,“Spatial and temporalfiltering of a10-W Nd:Y AG laser with a Fabry-Perot ring-cavity premode cleaner,”Opt.Lett.23,1704–1706 (1998).19.J.H.P¨o ld,“Stabilization of the Advanced LIGO200W laser,”Diploma thesis,Leibniz Universit¨a t Hannover(2009).20. E.D.Black,“An introduction to Pound-Drever-Hall laser frequency stabilization,”Am.J.Phys.69,79–87(2001).21.R.W.P.Drever,J.L.Hall,F.V.Kowalski,J.Hough,G.M.Ford,A.J.Munley,and H.Ward,“Laser phase andfrequency stabilization using an optical resonator,”Appl.Phys.B31,97–105(1983).22. A.Bullington,ntz,M.Fejer,and R.Byer,“Modal frequency degeneracy in thermally loaded optical res-onators,”Appl.Opt.47,2840–2851(2008).23.G.Mueller,“Beam jitter coupling in Advanced LIGO,”Opt.Express13,7118–7132(2005).24.V.Delaubert,N.Treps,ssen,C.C.Harb,C.Fabre,m,and H.-A.Bachor,“TEM10homodynedetection as an optimal small-displacement and tilt-measurement scheme,”Phys.Rev.A74,053823(2006). 25.P.Kwee,B.Willke,and K.Danzmann,“Laser power noise detection at the quantum-noise limit of32A pho-tocurrent,”Opt.Lett.36,3563–3565(2011).26. A.Araya,N.Mio,K.Tsubono,K.Suehiro,S.Telada,M.Ohashi,and M.Fujimoto,“Optical mode cleaner withsuspended mirrors,”Appl.Opt.36,1446–1453(1997).27.P.Kwee,B.Willke,and K.Danzmann,“Shot-noise-limited laser power stabilization with a high-power photodi-ode array,”Opt.Lett.34,2912–2914(2009).28. ntz,P.Fritschel,H.Rong,E.Daw,and G.Gonz´a lez,“Quantum-limited optical phase detection at the10−10rad level,”J.Opt.Soc.Am.A19,91–100(2002).1.IntroductionInterferometric gravitational wave detectors[1,2]perform one of the most precise differential length measurements ever.Their goal is to directly detect the faint signals of gravitational waves emitted by astrophysical sources.The Advanced LIGO(Laser Interferometer Gravitational-Wave Observatory)[3]project is currently installing three second-generation,ground-based detectors at two observatory sites in the USA.The4kilometer-long baseline Michelson inter-ferometers have an anticipated tenfold better sensitivity than theirfirst-generation counterparts (Inital LIGO)and will presumably reach a strain sensitivity between10−24and10−23Hz−1/2.One key technology necessary to reach this extreme sensitivity are ultra-stable high-power laser systems[4,5].A high laser output power is required to reach a high signal-to-quantum-noise ratio,since the effect of quantum noise at high frequencies in the gravitational wave readout is reduced with increasing circulating laser power in the interferometer.In addition to quantum noise,technical laser noise coupling to the gravitational wave channel is a major noise source[6].Thus it is important to reduce the coupling of laser noise,e.g.by optical design or by exploiting symmetries,and to reduce laser noise itself by various active and passive stabilization schemes.In this article,we report on the pre-stabilized laser(PSL)of the Advanced LIGO detector. The PSL is based on a high-power solid-state laser that is comprehensively stabilized.One laser system was set up at the Albert-Einstein-Institute(AEI)in Hannover,Germany,the so called PSL reference system.Another identical PSL has already been installed at one Advanced LIGO site,the one near Livingston,LA,USA,and two more PSLs will be installed at the second #161737 - $15.00 USD Received 18 Jan 2012; revised 27 Feb 2012; accepted 4 Mar 2012; published 24 Apr 2012 (C) 2012 OSA7 May 2012 / Vol. 20, No. 10 / OPTICS EXPRESS 10618site at Hanford,WA,USA.We have characterized the reference PSL and thefirst observatory PSL.For this we measured various beam parameters and noise levels of the output beam in the gravitational wave detection frequency band from about10Hz to10kHz,measured the performance of the active and passive stabilization schemes,and determined upper bounds for the cross coupling between different control loops.At the time of writing the PSL reference system has been operated continuously for more than18months,and continues to operate reliably.The reference system delivered a continuous-wave,single-frequency laser beam at1064nm wavelength with a maximum power of150W with99.5%in the TEM00mode.The active and passive stabilization schemes efficiently re-duced the technical laser noise by several orders of magnitude such that most design require-ments[5,7]were fulfilled.In the gravitational wave detection frequency band the relative power noise was as low as2×10−8Hz−1/2,relative beam pointingfluctuations were as low as1×10−7Hz−1/2,and an in-loop measurement of the frequency noise was consistent with the maximum acceptable frequency noise of about0.1HzHz−1/2.The cross couplings between the control loops were,in general,rather small or at the expected levels.Thus we were able to optimize each loop individually and observed no instabilities due to cross couplings.This stabilized laser system is an indispensable part of Advanced LIGO and fulfilled nearly all design goals concerning the maximum acceptable noise levels of the different beam pa-rameters right after installation.Furthermore all or a subset of the implemented stabilization schemes might be of interest for many other high-precision optical experiments that are limited by laser noise.Besides gravitational wave detectors,stabilized laser systems are used e.g.in the field of optical frequency standards,macroscopic quantum objects,precision spectroscopy and optical traps.In the following section the laser system,the stabilization scheme and the characterization methods are described(Section2).Then,the results of the characterization(Section3)and the conclusions(Section4)are presented.ser system and stabilizationThe PSL consists of the laser,developed and fabricated by Laser Zentrum Hannover e.V.(LZH) and neoLASE,and the stabilization,developed and integrated by AEI.The optical components of the PSL are on a commercial optical table,occupying a space of about1.5×3.5m2,in a clean,dust-free environment.At the observatory sites the optical table is located in an acoustically isolated cleanroom.Most of the required electronics,the laser diodes for pumping the laser,and water chillers for cooling components on the optical table are placed outside of this cleanroom.The laser itself consists of three stages(Fig.1).An almostfinal version of the laser,the so-called engineering prototype,is described in detail in[8].The primary focus of this article is the stabilization and characterization of the PSL.Thus only a rough overview of the laser and the minor modifications implemented between engineering prototype and reference system are given in the following.Thefirst stage,the master laser,is a commercial non-planar ring-oscillator[9,10](NPRO) manufactured by InnoLight GmbH in Hannover,Germany.This solid-state laser uses a Nd:Y AG crystal as the laser medium and resonator at the same time.The NPRO is pumped by laser diodes at808nm and delivers an output power of2W.An internal power stabilization,called the noise eater,suppresses the relaxation oscillation at around1MHz.Due to its monolithic res-onator,the laser has exceptional intrinsic frequency stability.The two subsequent laser stages, used for power scaling,inherit the frequency stability of the master laser.The second stage(medium-power amplifier)is a single-pass amplifier[11]with an output power of35W.The seed laser beam from the NPRO stage passes through four Nd:YVO4crys-#161737 - $15.00 USD Received 18 Jan 2012; revised 27 Feb 2012; accepted 4 Mar 2012; published 24 Apr 2012 (C) 2012 OSA7 May 2012 / Vol. 20, No. 10 / OPTICS EXPRESS 10619power stabilizationFig.1.Pre-stabilized laser system of Advanced LIGO.The three-staged laser(NPRO,medium power amplifier,high power oscillator)and the stabilization scheme(pre-mode-cleaner,power and frequency stabilization)are shown.The input-mode-cleaner is not partof the PSL but closely related.NPRO,non-planar ring oscillator;EOM,electro-optic mod-ulator;FI,Faraday isolator;AOM,acousto-optic modulator.tals which are longitudinally pumped byfiber-coupled laser diodes at808nm.The third stage is an injection-locked ring oscillator[8]with an output power of about220W, called the high-power oscillator(HPO).Four Nd:Y AG crystals are used as the active media. Each is longitudinally pumped by sevenfiber-coupled laser diodes at808nm.The oscillator is injection-locked[12]to the previous laser stage using a feedback control loop.A broadband EOM(electro-optic modulator)placed between the NPRO and the medium-power amplifier is used to generate the required phase modulation sidebands at35.5MHz.Thus the high output power and good beam quality of this last stage is combined with the good frequency stability of the previous stages.The reference system features some minor modifications compared to the engineering proto-type[8]concerning the optics:The external halo aperture was integrated into the laser system permanently improving the beam quality.Additionally,a few minor designflaws related to the mechanical structure and the optical layout were engineered out.This did not degrade the output performance,nor the characteristics of the locked laser.In general the PSL is designed to be operated in two different power modes.In high-power mode all three laser stages are engaged with a power of about160W at the PSL output.In low-power mode the high-power oscillator is turned off and a shutter inside the laser resonator is closed.The beam of the medium-power stage is reflected at the output coupler of the high power stage leaving a residual power of about13W at the PSL output.This low-power mode will be used in the early commissioning phase and in the low-frequency-optimized operation mode of Advanced LIGO and is not discussed further in this article.The stabilization has three sections(Fig.1:PMC,PD2,reference cavity):A passive resonator, the so called pre-mode-cleaner(PMC),is used tofilter the laser beam spatially and temporally (see subsection2.1).Two pick-off beams at the PMC are used for the active power stabilization (see subsection2.2)and the active frequency pre-stabilization,respectively(see subsection2.3).In general most stabilization feedback control loops of the PSL are implemented using analog electronics.A real-time computer system(Control and Data Acquisition Systems,CDS,[13]) which is common to many other subsystems of Advanced LIGO,is utilized to control and mon-itor important parameters of the analog electronics.The lock acquisition of various loops,a few #161737 - $15.00 USD Received 18 Jan 2012; revised 27 Feb 2012; accepted 4 Mar 2012; published 24 Apr 2012 (C) 2012 OSA7 May 2012 / Vol. 20, No. 10 / OPTICS EXPRESS 10620slow digital control loops,and the data acquisition are implemented using this computer sys-tem.Many signals are recorded at different sampling rates ranging from16Hz to33kHz for diagnostics,monitoring and vetoing of gravitational wave signals.In total four real-time pro-cesses are used to control different aspects of the laser system.The Experimental Physics and Industrial Control System(EPICS)[14]and its associated user tools are used to communicate with the real-time software modules.The PSL contains a permanent,dedicated diagnostic instrument,the so called diagnostic breadboard(DBB,not shown in Fig.1)[15].This instrument is used to analyze two different beams,pick-off beams of the medium power stage and of the HPO.Two shutters are used to multiplex these to the DBB.We are able to measurefluctuations in power,frequency and beam pointing in an automated way with this instrument.In addition the beam quality quantified by the higher order mode content of the beam was measured using a modescan technique[16].The DBB is controlled by one real-time process of the CDS.In contrast to most of the other control loops in the PSL,all DBB control loops were implemented digitally.We used this instrument during the characterization of the laser system to measure the mentioned laser beam parameters of the HPO.In addition we temporarily placed an identical copy of the DBB downstream of the PMC to characterize the output beam of the PSL reference system.2.1.Pre-mode-cleanerA key component of the stabilization scheme is the passive ring resonator,called the pre-mode-cleaner(PMC)[17,18].It functions to suppress higher-order transverse modes,to improve the beam quality and the pointing stability of the laser beam,and tofilter powerfluctuations at radio frequencies.The beam transmitted through this resonator is the output beam of the PSL, and it is delivered to the subsequent subsystems of the gravitational wave detector.We developed and used a computer program[19]to model thefilter effects of the PMC as a function of various resonator parameters in order to aid its design.This led to a resonator with a bow-tie configuration consisting of four low-loss mirrors glued to an aluminum spacer. The optical round-trip length is2m with a free spectral range(FSR)of150MHz.The inci-dence angle of the horizontally polarized laser beam is6◦.Theflat input and output coupling mirrors have a power transmission of2.4%and the two concave high reflectivity mirrors(3m radius of curvature)have a transmission of68ppm.The measured bandwidth was,as expected, 560kHz which corresponds to afinesse of133and a power build-up factor of42.The Gaussian input/output beam had a waist radius of about568µm and the measured acquired round-trip Gouy phase was about1.7rad which is equivalent to0.27FSR.One TEM00resonance frequency of the PMC is stabilized to the laser frequency.The Pound-Drever-Hall(PDH)[20,21]sensing scheme is used to generate error signals,reusing the phase modulation sidebands at35.5MHz created between NPRO and medium power amplifier for the injection locking.The signal of the photodetector PD1,placed in reflection of the PMC, is demodulated at35.5MHz.This photodetector consists of a1mm InGaAs photodiode and a transimpedance amplifier.A piezo-electric element(PZT)between one of the curved mirrors and the spacer is used as a fast actuator to control the round-trip length and thereby the reso-nance frequencies of the PMC.With a maximum voltage of382V we were able to change the round-trip length by about2.4µm.An analog feedback control loop with a bandwidth of about 7kHz is used to stabilize the PMC resonance frequency to the laser frequency.In addition,the electronics is able to automatically bring the PMC into resonance with the laser(lock acquisition).For this process a125ms period ramp signal with an amplitude cor-responding to about one FSR is applied to the PZT of the PMC.The average power on pho-todetector PD1is monitored and as soon as the power drops below a given threshold the logic considers the PMC as resonant and closes the analog control loop.This lock acquisition proce-#161737 - $15.00 USD Received 18 Jan 2012; revised 27 Feb 2012; accepted 4 Mar 2012; published 24 Apr 2012 (C) 2012 OSA7 May 2012 / Vol. 20, No. 10 / OPTICS EXPRESS 10621dure took an average of about65ms and is automatically repeated as soon as the PMC goes off resonance.One real-time process of CDS is dedicated to control the PMC electronics.This includes parameters such as the proportional gain of the loop or lock acquisition parameters.In addition to the PZT actuator,two heating foils,delivering a maximum total heating power of14W,are attached to the aluminum spacer to control its temperature and thereby the roundtrip length on timescales longer than3s.We measured a heating and cooling1/e time constant of about2h with a range of4.5K which corresponds to about197FSR.During maintenance periods we heat the spacer with7W to reach a spacer temperature of about2.3K above room temperature in order to optimize the dynamic range of this actuator.A digital control loop uses this heater as an actuator to off-load the PZT actuator allowing compensation for slow room temperature and laser frequency drifts.The PMC is placed inside a pressure-tight tank at atmospheric pressure for acoustic shield-ing,to avoid contamination of the resonator mirrors and to minimize optical path length changes induced by atmospheric pressure variations.We used only low-outgassing materials and fabri-cated the PMC in a cleanroom in order to keep the initial mirror contamination to a minimum and to sustain a high long-term throughput.The PMCfilters the laser beam and improves the beam quality of the laser by suppress-ing higher order transverse modes[17].The acquired round-trip Gouy phase of the PMC was chosen in such a way that the resonance frequencies of higher order TEM modes are clearly separated from the TEM00resonance frequency.Thus these modes are not resonant and are mainly reflected by the PMC,whereas the TEM00mode is transmitted.However,during the design phase we underestimated the thermal effects in the PMC such that at nominal circu-lating power the round-trip Gouy-phase is close to0.25FSR and the resonance of the TEM40 mode is close to that of the TEM00mode.To characterize the mode-cleaning performance we measured the beam quality upstream and downstream of the PMC with the two independent DBBs.At150W in the transmitted beam,the circulating power in the PMC is about6.4kW and the intensity at the mirror surface can be as high as1.8×1010W m−2.At these power levels even small absorptions in the mirror coatings cause thermal effects which slightly change the mirror curvature[22].To estimate these thermal effects we analyzed the transmitted beam as a function of the circulating power using the DBB.In particular we measured the mode content of the LG10and TEM40mode.Changes of the PMC eigenmode waist size showed up as variations of the LG10mode content.A power dependence of the round-trip Gouy phase caused a variation of the power within the TEM40mode since its resonance frequency is close to a TEM00mode resonance and thus the suppression of this mode depends strongly on the Gouy phase.We adjusted the input power to the PMC such that the transmitted power ranged from100W to 150W corresponding to a circulating power between4.2kW and6.4kW.We used our PMC computer simulation to deduce the power dependence of the eigenmode waist size and the round-trip Gouy phase.The results are given in section3.1.At all circulating power levels,however,the TEM10and TEM01modes are strongly sup-pressed by the PMC and thus beam pointingfluctuations are reduced.Pointingfluctuations can be expressed tofirst order as powerfluctuations of the TEM10and TEM01modes[23,24].The PMC reduces thefield amplitude of these modes and thus the pointingfluctuations by a factor of about61according to the measuredfinesse and round-trip Gouy phase.To keep beam point-ingfluctuations small is important since they couple to the gravitational wave channel by small differential misalignments of the interferometer optics.Thus stringent design requirements,at the10−6Hz−1/2level for relative pointing,were set.To verify the pointing suppression effect of the PMC we used DBBs to measure the beam pointingfluctuations upstream and downstream #161737 - $15.00 USD Received 18 Jan 2012; revised 27 Feb 2012; accepted 4 Mar 2012; published 24 Apr 2012 (C) 2012 OSA7 May 2012 / Vol. 20, No. 10 / OPTICS EXPRESS 10622Fig.2.Detailed schematic of the power noise sensor setup for thefirst power stabilizationloop.This setup corresponds to PD2in the overview in Fig.1.λ/2,waveplate;PBS,polar-izing beam splitter;BD,glassfilters used as beam dump;PD,single element photodetector;QPD,quadrant photodetector.of the PMC.The resonator design has an even number of nearly normal-incidence reflections.Thus the resonance frequencies of horizontal and vertical polarized light are almost identical and the PMC does not act as polarizer.Therefore we use a thin-film polarizer upstream of the PMC to reach the required purity of larger than100:1in horizontal polarization.Finally the PMC reduces technical powerfluctuations at radio frequencies(RF).A good power stability between9MHz and100MHz is necessary as the phase modulated light in-jected into the interferometer is used to sense several degrees of freedom of the interferometer that need to be controlled.Power noise around these phase modulation sidebands would be a noise source for the respective stabilization loop.The PMC has a bandwidth(HWHM)of about 560kHz and acts tofirst order as a low-passfilter for powerfluctuations with a-3dB corner frequency at this frequency.To verify that the suppression of RF powerfluctuations is suffi-cient to fulfill the design requirements,we measured the relative power noise up to100MHz downstream of the PMC with a dedicated experiment involving the optical ac coupling tech-nique[25].In addition the PMC serves the very important purpose of defining the spatial laser mode for the downstream subsystem,namely the input optics(IO)subsystem.The IO subsystem is responsible,among other things,to further stabilize the laser beam with the suspended input mode cleaner[26]before the beam will be injected into the interferometer.Modifications of beam alignment or beam size of the laser system,which were and might be unavoidable,e.g., due to maintenance,do not propagate downstream of the PMC tofirst order due to its mode-cleaning effect.Furthermore we benefit from a similar isolating effect for the active power and frequency stabilization by using the beams transmitted through the curved high-reflectivity mirrors of the PMC.2.2.Power stabilizationThe passivefiltering effect of the PMC reduces powerfluctuations significantly only above the PMC bandwidth.In the detection band from about10Hz to10kHz good power stability is required sincefluctuations couple via the radiation pressure imbalance and the dark-fringe offset to the gravitational wave channel.Thus two cascaded active control loops,thefirst and second power stabilization loop,are used to reduce powerfluctuations which are mainly caused by the HPO stage.Thefirst loop uses a low-noise photodetector(PD2,see Figs.1and2)at one pick-off port #161737 - $15.00 USD Received 18 Jan 2012; revised 27 Feb 2012; accepted 4 Mar 2012; published 24 Apr 2012 (C) 2012 OSA7 May 2012 / Vol. 20, No. 10 / OPTICS EXPRESS 10623of the PMC to measure the powerfluctuations downstream of the PMC.An analog electronics feedback control loop and an AOM(acousto-optic modulator)as actuator,located upstream of the PMC,are used to stabilize the power.Scattered light turned out to be a critical noise source for thisfirst loop.Thus we placed all required optical and opto-electronic components into a box to shield from scattered light(see Fig.2).The beam transmitted by the curved PMC mirror has a power of about360mW.This beam isfirst attenuated in the box using aλ/2waveplate and a thin-film polarizer,such that we are able to adjust the power on the photodetectors to the optimal operation point.Afterwards the beam is split by a50:50beam splitter.The beams are directed to two identical photode-tectors,one for the control loop(PD2a,in-loop detector)and one for independent out-of-loop measurements to verify the achieved power stability(PD2b,out-of-loop detector).These pho-todetectors consist of a2mm InGaAs photodiode(PerkinElmer C30642GH),a transimpedance amplifier and an integrated signal-conditioningfilter.At the chosen operation point a power of about4mW illuminates each photodetector generating a photocurrent of about3mA.Thus the shot noise is at a relative power noise of10−8Hz−1/2.The signal conditioningfilter has a gain of0.2at very low frequencies(<70mHz)and amplifies the photodetector signal in the im-portant frequency range between3.3Hz and120Hz by about52dB.This signal conditioning filter reduces the electronics noise requirements on all subsequent stages,but has the drawback that the range between3.3Hz and120Hz is limited to maximum peak-to-peak relative power fluctuations of5×10−3.Thus the signal-conditioned channel is in its designed operation range only when the power stabilization loop is closed and therefore it is not possible to measure the free running power noise using this channel due to saturation.The uncoated glass windows of the photodiodes were removed and the laser beam hits the photodiodes at an incidence angle of45◦.The residual reflection from the photodiode surface is dumped into a glassfilter(Schott BG39)at the Brewster angle.Beam positionfluctuations in combination with spatial inhomogeneities in the photodiode responsivity is another noise source for the power stabilization.We placed a silicon quadrant photodetector(QPD)in the box to measure the beam positionfluctuations of a low-power beam picked off the main beam in the box.The beam parameters,in particular the Gouy phase,at the QPD are the same as on the power sensing detectors.Thus the beam positionfluctuations measured with the QPD are the same as the ones on the power sensing photodetectors,assuming that the positionfluctuations are caused upstream of the QPD pick-off point.We used the QPD to measure beam positionfluctuations only for diagnostic and noise projection purposes.In a slightly modified experiment,we replaced one turning mirror in the path to the power sta-bilization box by a mirror attached to a tip/tilt PZT element.We measured the typical coupling between beam positionfluctuations generated by the PZT and the residual relative photocurrent fluctuations measured with the out-of-the-loop photodetector.This coupling was between1m−1 and10m−1which is a typical value observed in different power stabilization experiments as well.We measured this coupling factor to be able to calculate the noise contribution in the out-of-the-loop photodetector signal due to beam positionfluctuations(see Subsection3.3).Since this tip/tilt actuator was only temporarily in the setup,we are not able to measure the coupling on a regular basis.Both power sensing photodetectors are connected to analog feedback control electronics.A low-pass(100mHz corner frequency)filtered reference value is subtracted from one signal which is subsequently passed through several control loopfilter stages.With power stabilization activated,we are able to control the power on the photodetectors and thereby the PSL output power via the reference level on time scales longer than10s.The reference level and other important parameters of these electronics are controlled by one dedicated real-time process of the CDS.The actuation or control signal of the electronics is passed to an AOM driver #161737 - $15.00 USD Received 18 Jan 2012; revised 27 Feb 2012; accepted 4 Mar 2012; published 24 Apr 2012 (C) 2012 OSA7 May 2012 / Vol. 20, No. 10 / OPTICS EXPRESS 10624。
全氘甲烷大气示踪剂测量技术
第39卷第5期原子能科学技术Vol.39,No.5 2005年9月Atomic Energy Science and Technology Sep.2005全氘甲烷大气示踪剂测量技术陈绍华,邢丕峰,罗顺忠,羊衍秋(中国工程物理研究院核物理与化学研究所,四川绵阳 621900)摘要:文章通过系统研究甲烷中痕量全氘甲烷的分析方法、分析条件和检测能力等,证明了脉冲进样四极质谱(QMS)法用于大气扩散实验中全氘甲烷的浓度测量是可行的。
同时研究建立了痕量全氘甲烷脉冲进样QMS测量技术。
在50mL/min He流洗、分流比1∶100、电子倍增器检测、慢扫描和SIM模式测量条件下,CD4的最小检测量(体积分数)为511×10-9。
结合天然甲烷与全氘甲烷同位素分离技术,对甲烷中CD4的最小检测量可达到5×10-10,对空气中CD4的探测下限约为815×10-15。
研究表明:气相色谱2四极质谱(GC2QMS)法对CD4的探测下限约是脉冲进样QMS法的40倍。
关键词:测量技术;示踪剂;全氘甲烷;气相色谱2四极质谱法中图分类号:O657163 文献标识码:A 文章编号:100026931(2005)0520409206Measurement T echnologyof Atmospheric T racer Deuterated MethanesC H EN Shao2hua,XIN G Pi2feng,L UO Shun2zhong,YAN G Yan2qiu(I nstitute of N uclear Physics and Chemist ry,China A cadem y of Engineering Physics,P.O.B ox9192220,M iany ang621900,China)Abstract:Analyzing met hods,analyzing condition and testing ability of t race deuterated met hanes CD4in met hane were st udied.The result shows t hat t he measuring met hod of CD4concent ration in at mosp here diff usion test s by p ulse injecting quadrupole mass spec2 t rometer(QMS)met hod is feasible.Pulse injection QMS measuring technology of t race CD4was established.On such condition as rinsing2He gases flow50mL/min,splitting ratio1∶100,electron multiplier testing,slow scanning and SIM modeling,t he lowest detectable limit of CD4in met hane is5.1×bined wit h t he isotope separate technology of CD4and met hane,t he lowest detectable limit of CD4in met hane is5.0×10-10,and for CD4in air,which is8.5×10-15.It is shown t hat t he lowest detectable limit of CD4by gas chromatograp hy2quadrupole mass spect rometer met hod is40times of p ulse injection QMS met hod.K ey w ords:measurement technology;tracer;deuterated methanes;gas chromatography2 quadrupole mass spectro meter收稿日期:2003212222;修回日期:2004212209基金项目:中国工程物理研究院核科学研究基金资助项目(2001077)作者简介:陈绍华(1969—),男,四川安县人,副研究员,博士,分离理论与设备专业 全氘甲烷(12CD4和13CD4)是目前已知的最有发展前途的非放射性远程大气扩散示踪剂之一。
溴到硼酸酯
Materials Chemistry C
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Cite this: J. Mater. Chem. C, 2015, 3, 861
However, these oligouorene functionalized oligomers may suffer from the unwanted long wavelength emission under long-term device operation, similar to polyuorene-based macromolecules.34–36
Received 26th September 2014 Accepted 17th November 2014 DOI: 10.1039/c4tc02173h /MaterialsC
Starburst 4,40,400-tris(carbazol-9-yl)triphenylamine-based deep-blue fluorescent emitters with tunable oligophenyl length for solution-processed undoped organic lightemitting diodes†
Introduction
Since 1987, organic light-emitting diodes (OLEDs) have attracted tremendous attention due to their potential applications in at-panel displays and solid-state lightings.1–10 To achieve fullcolor displays, three primary RGB luminescent materials with excellent stability, efficiency and color purity are required. With respect to green and red counterparts, it seems to be a big challenge to develop blue emitters, especially deep-blue ones that have a Commission Internationale de l'Eclairage (CIE) y coordinate value of <0.10, because the intrinsic wide bandgap would inevitably result in inefficient charge injection to an emitting layer (EML).11 Therefore, great efforts should be paid to the design of deep-blue emitters to push forward the commercialization of full-color OLEDs.
基于激光诱导击穿光谱和拉曼光谱对四唑类化合物的快速识别和分类实验研究
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２ 实验部分
２．１ 实验装置 ＬＩＢＳＲａｍａｎ集成测试系统如图 １所示，样品
８９０
中国光学
第 １２卷
图 １ ＬＩＢＳＲａｍａｎ集成测试系统 Ｆｉｇ．１ Ｓｃｈｅｍａｔｉｃｄｉａｇｒａｍ ｏｆｉｎｔｅｇｒａｔｅｄＬＩＢＳＲａｍａｎ
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放置 在 三 维 电 动 样 品 台 上。 Ｒａｍａｎ测 试 采 用 １０６４ｎｍ单纵 模 连 续 激 光 器，最 大 输 出 功 率 为 ５００ｍＷ。激光通过反射棱镜打到样品表面，散射 光通过两个银镜和一个焦距为 １５０ｍｍ的透镜耦 合进光栅光谱仪（ｉＨＲ５５０，光栅刻痕为 １２００线 ／ ｍｍ），１０６４ｎｍ 陷 波 滤 光 片 位 于 两 个 反 射 镜 之 间，滤掉激发光。ＬＩＢＳ测试光源 为 主 动 调 Ｑ的 Ｎｄ∶ＹＡＧ（ＱｕａｎｔｅｌＵｌｔｒａ，Ｆｒｅｎｃｈ）固体激光器，波长
醇类物溶液的紫外吸收光谱和荧光光谱的研究
ｓｏｍｅ ｒｅｆｅｒｅｎｃｅ ｖａｌｕｅ ｉｎ ｔｈｅｏｒｙ．
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ｂａｃｋｇｒｏｕｎｄ，ｔｈｅ ａｂｓｏｒｐｔｉｏｎ ａｎｄ ｆｌｕｏｒｅｓｃｅｎｃｅ印ｅｃ订ＩｌＩ］【ｌｓ ｏｆ １２·Ｐｒｏｐｙｌｅｎｅ Ｇｌｙｃｏｌ， １，３一Ｐｒｏｐａｎｅｄｉｏｌ ａｎｄ Ｄｉｅｔｈｙｌｅｎｅ Ｇｌｙｃｏｌ ｈａｖｅ ｂｅｅｎ ｄｅｔｅｃｔｅｄ ｓｅｐａｒａｔｅｌｙ，ｗｈｉｃｈ ｐｒｏｖｅｄ ｔｏ ｂｅ ａ ｋｉｎｄ ｏｆ ｆａｓｔ ａｎｄ ｅｆｆｅｃｔｉｖｅ ｄｉｆｆｅｒｅｎｔｉａｔｉｏｎ ｍｅｔｈｏｄ．Ｗｅ ｃａｎ ｄｉｓｔｉｎｇｕｉｓｈ
ｍａｔｅｒｉａｌｓ ｗｃｒｅ ｏｎｌｙ ｌｒｅａｔｅｄ硒ｏｒｇａｎｉｃ ｓｏｌｕｔｉｏｎｓ．ｏｔｈｅｒ ｔｈａｎ ｍａｔｅｒｉａｌｓ ｗｈｏｓｅ
ｃｈａｒａｃ耐ｓｔｉｅｓ ｆｌｕｏｒｅｓｃｅｎｃｅ
ｓｈｏｕｌｄ ｂｅ ｃｏｎｓｉｄｅｒｅｄ．Ｉｎ ａｄｄｉｔｉｏｎ，ｔｈｅ ｆｌｕｏｒｅｓｃｅｎｃｅ
ｌｉｆｅｔｉｍｅ ｖａｌｕｅｓ ｆｏｒ ｔｈｅ ｓｅｖｅｎ ｍａｔｅｒｉａｌｓ ｈａｖｅ ｂｅｅｎ ｃａｌｃｕｌａｔｅｄ ｏｕｔ ｔｈｒｏｕｇｈ Ｆｏｒｓｔｅｒ
关键词：光谱学，吸收光谱，荧光光谱，醇类物溶液，荧光量子效率，荧光寿命， 参比法
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分等级大微孔、介孔大孔
ARTICLEOPENReceived11Dec2012|Accepted16May2013|Published14Jun2013A solid with a hierarchical tetramodalmicro-meso-macro pore size distributionYu Ren1,Zhen Ma2,3,Russell E.Morris1,Zheng Liu1,Feng Jiao4,Sheng Dai3&Peter G.Bruce1Porous solids have an important role in addressing some of the major energy-related pro-blems facing society.Here we describe a porous solid,a-MnO2,with a hierarchical tetramodalpore size distribution spanning the micro-,meso-and macro pore range,centred at0.48,4.0,18and70nm.The hierarchical tetramodal structure is generated by the presence ofpotassium ions in the precursor solution within the channels of the porous silica template;thesize of the potassium ion templates the microporosity of a-MnO2,whereas theirreactivity with silica leads to larger mesopores and macroporosity,without destroying themesostructure of the template.The hierarchical tetramodal pore size distribution influencesthe properties of a-MnO2as a cathode in lithium batteries and as a catalyst,changingthe behaviour,compared with its counterparts with only micropores or bimodalmicro/mesopores.The approach has been extended to the preparation of LiMn2O4with ahierarchical pore structure.1EaStCHEM,School of Chemistry,University of St Andrews,St Andrews KY169ST,UK.2Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention(LAP3),Department of Environmental Science and Engineering,Fudan University,Shanghai200433,China.3Chemical Sciences Division,Oak Ridge National Laboratory,Oak Ridge,T ennessee37831,USA.4Department of Chemical and Biomolecular Engineering,University of Delaware,Newark,Delaware19716,USA.Correspondence and requests for materials should be addressed to P.G.B.(email:p.g.bruce@).P orous solids have an important role in addressing some of the major problems facing society in the twenty-first century,such as energy storage,CO2sequestration,H2 storage,therapeutics(for example,drug delivery)and catalysis1–8. The size of the pores and their distribution directly affect their ability to function in a particular application2.For example, zeolites are used as acid catalysts in industry,but their micropores impose severe diffusion limitations on the ingress and egress of the reactants and the catalysed products9.To address such issues, great effort is being expended in preparing porous materials with a bimodal(micro and meso)pore structure by synthesizing zeolites or silicas containing micropores and mesopores10–17,or microporous metal–organic frameworks with ordered mesopores18.Among porous solids,porous transition metal oxides are particularly important,because they exhibit many unique properties due to their d-electrons and the variable redox state of their internal surfaces8,19–22.Here we describe thefirst solid(a-MnO2)possessing hierarchical pores spanning the micro,meso and macro range, centred at0.48,4.0,18and70nm.The synthesis method uses mesoporous silica as a hard template.Normally such a template generates a mesoporous solid with a unimodal23–31or,at most,a bimodal pore size distribution32–38.By incorporating Kþions in the precursor solution,within the silica template,the Kþions act bifunctionally:their size templates the formation of the micropores in a-MnO2,whereas their reactivity with silica destroys the microporous channels in KIT-6comprehensively, leading to the formation of a-MnO2containing large mesopores and,importantly,macropores,something that has not been possible by other methods.Significantly,this is achieved without destroying the silica template by alkaline ions.The effect of the tetramodal pore structure on the properties of the material is exemplified by considering their use as electrodes for lithium-ion batteries and as a catalyst for CO oxidation and N2O decomposition.The novel material offers new possibilities for combining the selectivity of small pores with the transport advantages of the large pores across a wide range of sizes.We also present results demonstrating the extension of the method to the synthesis of LiMn2O4with a hierarchical pore structure.ResultsComposition of tetramodal a-MnO2.The composition of the synthesized material was determined by atomic absorption ana-lysis and redox titration to be K0.08MnO2(the K/Mn ratio of the precursor solution was1/3).The material is commonly referred to as a-MnO2,because of the small content of Kþ19.N2sorption analysis of tetramodal a-MnO2.The tetramodal a-MnO2shows a type IV isotherm(Fig.1a).The pore size dis-tribution(Fig.1b)in the range of0.3–200nm was analysed using the density functional theory(DFT)method applied to the adsorption branch of the isotherm39–42,as this is more reliable than analysing the desorption branch43;note that this is not the DFT method used in ab initio electronic structure calculations. Plots were constructed with vertical axes representing ‘incremental pore volume’and‘incremental surface area’.Large (macro)pores can account for a significant pore volume while representing a relatively smaller surface area and vice versa for small(micro)pores.Therefore,when investigating a porous material with a wide range of pore sizes,for example,micropore and macropore,the combination of surface area and pore volume is essential to determine the pore size distribution satisfactorily (Fig.1b).Considering both pore volume and surface area, significant proportions of micro-,meso-and macropores are evident,with distinct maxima centred at0.70,4.0,18and70nm.To probe the size of the micropores more precisely than is possible with DFT,the Horvath–Kawazoe pore size distribution analysis was employed44.A single peak was obtained at0.48nm(Fig.1c),in good accord with the0.46-nm size of the2Â2channels of a-MnO2 (refs.19,21).The relatively small Brunauer–Emmett–Teller(BET) surface area of tetramodal a-MnO2(79–105m2gÀ1; Supplementary Table S1)compared with typical surface areas of mesoporous metal oxides(90–150m2gÀ1)45is due to the significant proportion of macropores(which have small surface areas)and relatively large(18nm)mesopores—a typical mesoporous metal oxide has only3–4nm pores.TEM analysis of tetramodal a-MnO2.Transmission electron microscopic(TEM)data for tetramodal a-MnO2,Fig.2, demonstrates a three-dimensional pore structure with a sym-metry consistent with space group Ia3d.From the TEM data,an a0lattice parameter of23.0nm for the mesostructure could be extracted,which is in good agreement with the value obtained from the low-angle powder X-ray diffraction(PXRD)data, a0¼23.4nm(Supplementary Fig.S1a).High-resolution TEM images in Fig.2c–e demonstrate that the walls are crystalline with a typical wall thickness of10nm.The lattice spacings of0.69,0.31 and0.35nm agree well with the values of6.92,3.09and3.46Åfor the[110],[310]and[220]planes of a-MnO2(International Centre for Diffraction Data(ICDD)number00-044-0141), respectively.The wide-angle PXRD data matches well with the PXRD data of bulk cryptomelane a-MnO2(Supplementary Fig. S1b),confirming the crystalline walls.The various pores in tetramodal a-MnO2can be observed by TEM directly:the0.48-nm micropores are seen in Fig.2e(2Â2 tunnels with dimensions of0.48Â0.48nm in the white box);the 4.0-nm pores are shown in Fig.2b–d;the18-nm pores are shown in Fig.2a;the70-nm pores are evident in Fig.2b(highlighted with white circles).Li intercalation.Li can be intercalated into bulk a-MnO2 (ref.46).Therefore,it is interesting to compare Li intercalation into bulk a-MnO2(micropores only)and bimodal a-MnO2 (micropores along with a single mesopore of diameter3.6nm,see Methods)with tetramodal a-MnO2(micro-,meso-and macropores).Each of the three a-MnO2materials was subjected to Li intercalation by incorporation as the positive electrode in a lithium battery,along with a lithium anode and a non-aqueous electrolyte(see Methods).The results of cycling(repeated intercalation/deintercalation of Li)the cells are shown in Fig.3. Although all exhibit good capacity to cycle Li at low rates of charge/discharge(30mA gÀ1),tetramodal a-MnO2shows sig-nificantly higher capacity(Li storage)at a high rate of 6,000mA gÀ1(corresponding to charge and discharge in3min). The tetramodal a-MnO2can store three times the capacity(Li) compared with bimodal a-MnO2,and18times that of a-MnO2 with only micropores,at the high rate of intercalation/deinter-calation(Fig.3).The superior rate capability of tetramodal a-MnO2over microporous and bimodal forms may be assigned to better Liþtransport in the electrolyte within the hierarchical pore structure of tetramodal a-MnO2.The importance of elec-trolyte transport in porous electrodes has been discussed recently35,47,48and the results presented here reinforce the beneficial effect of a hierarchical pore structure.Catalytic studies.CO oxidation and N2O decomposition were used as reactions to probe the three different forms of a-MnO2as catalysts(Supplementary Fig.S2).As shown in Supplementary Fig.S2a,tetramodal a-MnO2demonstrates better catalytic activity compared with only micropores or bimodal a-MnO2;thetemperature of half CO conversion (T 50)was 124°C for tetra-modal a -MnO 2,whereas microporous and bimodal a -MnO 2exhibited a T 50value of 275°C and 209°C,respectively.In the case of N 2O decomposition,a -MnO 2with only micropores demonstrated no catalytic activity in the range of 200–400°C,in accord with a previous report 49.Tetramodal and bimodal a -MnO 2showed catalytic activity and reached 32%and 20%of N 2O conversion,respectively,at a reaction temperature of 400°C.The differences in catalytic activity are related to the differences in the material.A detailed study focusing on the catalytic activity alonewould be necessary to demonstrate which specific features of the textural differences (pore size distribution,average manganese oxidation state,K þand so on)between the different MnO 2materials are responsible for the differences in behaviour.However,the preliminary results shown here do illustrate that such differences exist.Porous LiMn 2O 4.To demonstrate the wider applicability of the synthesis method,LiMn 2O 4with a hierarchical pore structurewas1801601401201008060402000.00.20.40.60.81.0V (c m 3 g –1)Pore diameter (nm)0.0120.0100.0080.0060.0040.0020.000I n c r e m e n t a l p o r e v o l u m e (c m 3 g –1)Pore width (nm)I n c r e m e n t a l s u r f a c e a r e a (m 2 g –1)I n c r e m e n t a l s u r f a c e a r e a (m 2 g –1)P /P 0Figure 1|N 2sorption analysis of tetramodal a -MnO 2.(a )N 2adsorption–desorption isotherms,(b )DFT pore size distribution and (c )Horvath–Kawazoe pore size distribution from N 2adsorption isotherm for tetramodal a -MnO 2.Figure 2|TEM images of tetramodal a -MnO 2.TEM images along (a )[100]direction,showing 18nm mesopores (scale bar,50nm);(b )4.0and 70nm pores (70nm pores are highlighted by white circles;scale bar,100nm);(c –e )high-resolution (HRTEM)images of tetramodal a -MnO 2showing 4.0and 0.48nm pores (scale bar,10nm).Inset is representation of a -MnO 2structure along the c axis,demonstrating the 2Â2micropores as shown in the HRTEM (white box)in e .Purple,octahedral MnO 6;red,oxygen;violet,potassium.synthesized in a way similar to that of tetramodal a -MnO 2.The main difference is the use of LiNO 3instead of KNO 3(see Methods).In this case,Li þreacts with the silica template col-lapsing/blocking the microporous channels in the KIT-6and resulting in the large mesopores and macropores (17and 50nm)in the LiMn 2O 4obtained.The use of Li þinstead of the larger K þdeters the formation of micropores because Li þis too small.TEM analysis illustrates the hierarchical pore structure of LiMn 2O 4(Supplementary Fig.S3):4.0nm pores are evident in Supplementary Fig.S3b;17nm pores in Supplementary Fig.S3a;and 50nm pores in Supplementary Fig.S3b (highlighted with white circles).The d-spacing of 0.47nm in the high-resolution TEM image (Supplementary Fig.S3c)is in good accordance with the values of 0.4655nm for the [111]planes of LiMn 2O 4(ICDD number 00-038-0789)and with the wide-angle PXRD data (Supplementary Fig.S4).The original DFT pore size distribution analysis from N 2sorption (adsorption branch)gives three pore sizes in the range of 1–100nm centred at 4.0,17and 50nm (Supplementary Fig.S5).A more in-depth presentation of the results for LiMn 2O 4will be given in a future paper;preliminary results presented here illustrate that the basic method can be applied beyond a -MnO 2.DiscussionTurning to the synthesis of the tetramodal a -MnO 2,the details are given in the Methods section.Hard templating using silica templates,such as KIT-6,normally gives rise to materials with unimodal or,at most,bimodal mesopore structures,and in the latter case the smaller mesopores dominate over the larger mesopores 8,32,35.Alkali ions are excellent templates for micropores in transition metal oxides 19,21,but they have been avoided in nanocasting from silica templates because of concerns that they would react with and,hence,destroy thesilica20018016014012010080604020D i s c h a r g e c a p a c i t y (m A h g –1)0Cycle numberx in Li x MnO 2Figure 3|Electrochemical behaviour of different a -MnO 2.Capacity retention for tetramodal a -MnO 2cycled at 30(empty blue circles)and 6,000mA g À1(filled blue circles);bulk a -MnO 2cycled at 30(empty red squares)and 6,000mA g À1(filled red squares);bimodal a -MnO 2cycled at 30(empty black triangle)and 6,000mA g À1(filled blacktriangles).18 nm pores70 nm poresTwo sets of mesoporeschannels connecting both sets of mesoporesEtching of silica Etching of silica Etching of silica template2discontinuously within one set of the KIT-6mesoporesFigure 4|Formation mechanism of meso and macropores in tetramodal a -MnO 2.When both KIT-6mesochannels are occupied by a -MnO 2and then the silica between them etched away,the remaining pore is 4nm (centre portion of figure).When a -MnO 2grows in only one set of mesochannels and then the KIT-6is dissolved away,the remaining metal oxide has 18nm pores (upper portion of figure).The comprehensive destruction of the microchannels in KIT-6by K þleads to a -MnO 2growing in only a proportion of one set of the KIT-6mesochannels,resulting in the formation of B 70nm pores (lower portion of figure).template50.Here,not only have alkali ions been used successfully in precursor solutions without destroying the template mesostructure but they give rise to macropores in the a-MnO2, thus permitting the synthesis of a tetramodal,micro-small,meso-large,meso-macro pore structure.Synthesis begins by impregnating the KIT-6silica template with a precursor solution containing Mn2þand Kþions.On heating,the Kþions template the formation of the micropores in a-MnO2,as the latter forms within the KIT-6template.KIT-6 consists of two interpenetrating mesoporous channels linked by microporous channels51–53.The branches of the two different sets of mesoporous channels in KIT-6are nearest neighbours separated by a silica wall of B4nm53;therefore,when both KIT-6mesochannels are occupied by a-MnO2and the silica between them etched away,the remaining pore is4nm(see centre portion of Fig.4).It has been shown previously,by a number of authors,that by varying the hydrothermal conditions used to prepare the KIT-6,the proportion of the microchannels can be decreased to some extent,thus making it difficult to simultaneouslyfill the neighbouring KIT-6mesoporous channels by the precursor solution of the target mesoporous metal oxide33–35.As a result,the target metal oxide grows in only one set of mesochannels of the KIT-6host but not both.When the KIT-6is dissolved away,the remaining metal oxide has B18nm pores,because the distance between adjacent branches of the same KIT-6mesochannels is greater than between the two different mesochannels in KIT-6.Here we propose that the Kþions have a similar effect on the KIT-6to that of the hydrothermal synthesis,but by a completely different mechanism.Reaction between the Kþions in the precursor solution with the silica during calcination results in the formation of Kþ-silicates,which cause collapse or blocking of the microporous channels in KIT-6,such that the a-MnO2grows in one set of the KIT-6mesochannels,giving rise to18nm pores in a-MnO2when the silica is etched away,see top portion of Fig.4. However,the reaction between Kþand the silica is more severe than the effect of varying the hydrothermal treatment.In the former case,the KIT-6microchannels are so comprehensively destroyed that the proportion of the large(18nm)to smaller (4nm)mesopores is greater than can be achieved by varying hydrothermal conditions.The comprehensive destruction of the microchannels in KIT-6by Kþ,perhaps augmented by some minor degradation of parts of the mesochannels,leads to a-MnO2 growing in only a proportion of one set of the KIT-6 mesochannels,resulting in the formation of B70nm pores in a-MnO2,see lower portion of Fig.4.In summary,the Kþreactivity with the silica goes beyond what can be achieved by varying the conditions of hydrothermal synthesis and is responsible for generating the tetramodal pore size distribution reported here. The mechanism of pore formation in a-MnO2by reaction between Kþand the silica template is supported by several findings.First,by the lower K/Mn molar ratio of thefinal tetramodal a-MnO2product(0.08)compared with the starting materials(0.33)implies that some of the Kþions in the impregnating solution have reacted with the silica.Second, support for collapse/blocking of the microporous channels in KIT-6due to reaction with Kþwas obtained by comparing the texture of KIT-6impregnated with an aqueous solution contain-ing only KNO3and calcined at300and500°C.The micropore volume in KIT-6is the greatest,with no KNO3in the solution;it then decreases continuously as the calcination temperature and calcination time is increased,such that after2and5h at500°C the micropore volume has decreased to zero(Supplementary Fig. S6).Third,we prepared tetramodal a-MnO2using a similar synthetic procedure to that described in the Methods section, except that this time we used a covered tall crucible for the calcination step.Sun et al.54have shown that using a covered,tall crucible when calcining results in porous metal oxides with much larger particle sizes.If the70-nm pores had arisen simply from the gaps between the particles,then the pore size would have changed;in contrast,it remained centred at70nm, Supplementary Fig.S7,consistent with the70-nm pores being intrinsic to the materials and arising from reaction with the Kþas described above.Fourth,if the synthesis of MnO2is carried out using the KIT-6template but in the absence Kþions,then the DFT pore size distribution shown in Supplementary Fig.S8is obtained.The0.48-and70-nm pores are now absent,but the4-and18-nm pores remain.This demonstrates the key role of Kþin the formation of the smallest and largest pores and,hence,in generating the tetramodal pore size distribution.The absence of Kþmeans that there is nothing to template the0.48nm pores and so a-MnO2is not formed;the b-polymorph is obtained instead.The absence of Kþalso means that the microchannels in the KIT-6template remain intact,resulting in no70nm pores and the dominance of the4-nm pores compared with the 18-nm pores.The hierarchical pore structure can be varied systematically by controlling the synthesis conditions,in particular the Kþ/Mn ratio of the precursor solution.A range of Kþ/Mn ratios,1/5,1/3and1/2,gave rise to a series of pore size distributions,in which the pore sizes remained the same but the relative proportions of the different pores varied (Supplementary Table S1).The higher the Kþ/Mn ratio,the greater the proportion of macropores and large mesopores.This is in accord with expectations,as the higher the Kþconcentra-tion in the precursor solution the greater the collapse/blocking of the microporous channels in the KIT-6(as noted above),and hence the greater the proportion of macropores and large mesopores.Indeed,these results offer further support for the mechanism of pore size distribution arising from reaction between Kþand the silica template.In conclusion,tetramodal a-MnO2,thefirst porous solid with a tetramodal pore size distribution,has been synthesized.Its hierarchical pore structure spans the micro,meso and macropore range between0.3and200nm,with pore dimensions centred at 0.48,4.0,18and70nm.Key to the synthesis is the use of Kþions that not only template the formation of micropores but also react with the silica template,therefore,breaking/blocking the micro-porous channels in the silica template far more comprehensively than is possible by varying the hydrothermal synthesis conditions, to the extent that macropores are formed,and without destroying the silica mesostructure by alkali ions,as might have been expected.The resulting hierarchical tetramodal structure demon-strates different behaviours compared with microporous and bimodal a-MnO2as a cathode material for Li-ion batteries,and when used as a catalyst for CO oxidation and N2O decomposi-tion.The method has been extended successfully to the preparation of hierarchical LiMn2O4.MethodsSynthesis.Tetramodal a-MnO2(surface area96m2gÀ1,K0.08MnO2)was pre-pared by two-solvent impregnation55using Kþand mesoporous silica KIT-6as the hard template.KIT-6was prepared according to a previous report (hydrothermal treatment at100°C)51.In a typical synthesis of tetramodal a-MnO2, 7.53g of Mn(NO3)2Á4H2O(98%,Aldrich)and1.01g of KNO3(99%,Aldrich)were dissolved in B10ml of water to form a solution with a molar ratio of Mn/K¼3.0. Next,5g of KIT-6was dispersed in200ml of n-hexane.After stirring at room temperature for3h,5ml of the Mn/K solution was added slowly with stirring.The mixture was stirred overnight,filtered and dried at room temperature until a completely dried powder was obtained.The sample was heated slowly to500°C (1°C minÀ1),calcined at that temperature for5h with a cover in a normal crucible unless is specified54and the resulting material treated three times with a hot aqueous KOH solution(2.0M),to remove the silica template,followed by washing with water and ethanol several times,and then drying at60°C.Bimodal a-MnO2(surface area58m2gÀ1,K0.06MnO2)with micropore and a single mesopore size of3.6nm was prepared by using mesoporous silica SBA-15as a hard template.The SBA-15was prepared according to a previous report56.Bulk a-MnO2(surface area8m2gÀ1,K0MnO2)was prepared by the reaction between325mesh Mn2O3(99.0%,Aldrich)and6.0M H2SO4solution at80°C for 24h,resulting in the disproportionation of Mn2O3into a soluble Mn2þspecies and the desired a-MnO2product46.Treatment of KIT-6with KNO3was carried out as follows:1.01g of KNO3was dissolved in B15ml of water to form a KNO3solution.Five grams of mesoporous KIT-6was dispersed in200ml of n-hexane.After stirring at room temperature for 3h,5ml of KNO3solution was added slowly with stirring.The mixture was stirred overnight,filtered and dried at room temperature until a completely dried powder was obtained.The sample was heated slowly to300or500°C(1°C minÀ1), calcined at that temperature for5h and the resulting material was washed with water and ethanol several times,and then dried at60°C overnight.The synthesis method for hierarchical porous LiMn2O4was similar to that of tetramodal a-MnO2.The main difference was to use1.01g of LiNO3instead of KNO3.After impregnation into KIT-6,calcination and silica etching,porous LiMn2O4was obtained.Characterization.TEM studies were carried out using a JEOL JEM-2011, employing a LaB6filament as the electron source,and an accelerating voltage of 200keV.TEM images were recorded by a Gatan charge-coupled device camera in a digital format.Wide-angle PXRD data were collected on a Stoe STADI/P powder diffractometer operating in transmission mode with Fe K a1source radiation(l¼1.936Å).Low-angle PXRD data were collected using a Rigaku/MSC,D/max-rB with Cu K a1radiation(l¼1.541Å)operating in reflection mode with a scintillation detector.N2adsorption–desorption analysis was carried out using a Micromeritics ASAP2020.The typical sample weight used was100–200mg. The outgas condition was set to300°C under vacuum for2h,and all adsorption–desorption measurements were carried out at liquid nitrogen tem-perature(À196°C).The original DFT method for the slit pore geometry was used to extract the pore size distribution from the adsorption branch usingthe Micromeritics software39–42.A Horvath–Kawazoe method was used to extract the microporosity44.Mn and K contents were determined by chemical analysis using a Philips PU9400X atomic adsorption spectrometer.The average oxidation state of framework manganese in a-MnO2samples was determined by a redoxtitration method57.Electrochemistry.First,the cathode was constructed by mixing the active material (a-MnO2),Kynar2801(a copolymer based on polyvinylidenefluoride),and Super S carbon(MMM)in the weight ratio80:10:10.The mixture was cast onto Al foil (99.5%,thickness0.050mm,Advent Research Materials,Ltd)from acetone using a Doctor-Blade technique.After solvent evaporation at room temperature and heating at80°C under vacuum for8h,the cathode was assembled into cells along with a Li metal anode and electrolyte(Merck LP30,1M LiPF6in1:1v/v ethylene carbonate/dimethyl carbonate).The cells were constructed and handled in anAr-filled MBraun glovebox(O2o0.1p.p.m.,H2O o0.1p.p.m.).Electrochemical measurements were carried out at30°C using a MACCOR Series4200cycler.Catalysis.Catalytic CO oxidation was tested in a plug-flow microreactor(Alta-mira AMI200).Fifty milligrams of catalyst was loaded into a U-shaped quartz tube (4mm i.d.).After the catalyst was pretreated inflowing8%O2(balanced with He) at400°C for1h,the catalyst was then cooled down,the gas stream switched to1% CO(balanced with air)and the reaction temperature ramped using a furnace(at a rate of1°C minÀ1above ambient temperature)to record the light-off curve.The flow rate of the reactant stream was37cm3minÀ1.A portion of the product stream was extracted periodically with an automatic sampling valve and was analysed using a dual column gas 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毛细管X光透镜聚焦的微束X射线荧光谱仪的研发及应用
毛细管X光透镜聚焦的微束X射线荧光谱仪的研发及应用程琳;段泽明;刘俊;姜其立;潘秋丽;李融武【摘要】针对不同样品的分析需求,本文设计了几种不同类型的微束X射线荧光谱仪.用高精度激光位移传感器实时校正样品表面被测量点与毛细管透镜出端之间的距离,以减少形状不规则的古陶瓷样品测量时带来的误差;利用毛细管X光透镜传输能量高于25 keV的X射线效率低的特点,将其应用于高铅釉瓷器彩料的无损分析中;采用大功率X射线源,扫描分析了大米中K、Ca等元素分布;以人民币5角硬币为例,研究了能量色散的微束X射线衍射方法.研究结果表明,本文研发的微束X射线荧光谱仪在生物样品和文物样品的分析研究中有广泛的应用前景.【期刊名称】《原子能科学技术》【年(卷),期】2018(052)012【总页数】7页(P2249-2255)【关键词】毛细管X光透镜;微束X射线荧光谱仪;便携式X射线荧光谱仪【作者】程琳;段泽明;刘俊;姜其立;潘秋丽;李融武【作者单位】北京师范大学核科学与技术学院射线束技术教育部重点实验室,北京100875;北京市辐射中心,北京 100875;北京师范大学核科学与技术学院射线束技术教育部重点实验室,北京 100875;北京市辐射中心,北京 100875;北京师范大学核科学与技术学院射线束技术教育部重点实验室,北京 100875;北京市辐射中心,北京100875;北京师范大学核科学与技术学院射线束技术教育部重点实验室,北京100875;北京市辐射中心,北京 100875;北京师范大学核科学与技术学院射线束技术教育部重点实验室,北京 100875;北京市辐射中心,北京 100875;北京师范大学核科学与技术学院射线束技术教育部重点实验室,北京 100875【正文语种】中文【中图分类】O657.34;TQ174.43毛细管X光透镜是一种重要的光学器件，由几百万根直径为几μm的空心毛细玻璃管在高温下融合而成。
毛细管X光透镜利用X射线全反射的原理，将从点光源X射线管激发出的X射线束在空心毛细玻璃管的内壁以全反射的方式进行传输，再利用毛细管的弯曲改变X射线束传输的方向，从而将其汇聚成直径几十或几百μm的X射线束，将其强度提高2～3个数量级，可在普通实验室实现微束X射线荧光分析[1-2]。
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arXiv:hep-ph/0609240v1 22 Sep 2006February2,20087:15WSPC-ProceedingsTrimSize:9inx6incolangelo˙qcd061
NEWOPENANDHIDDENCHARMSPECTROSCOPYP.COLANGELO∗,F.DEFAZIO,R.FERRANDES,S.NICOTRIIstitutoNazionalediFisicaNucleare,SezionediBari,Bari,Italy∗E-mail:pietro.colangelo@ba.infn.it
Manynewresultsonopenandhiddencharmspectroscopyhavebeenobtainedrecently.Wepresentashortreviewoftheexperimentalfindingsinthemesonsector,ofthetheoreticalinterpretationsandoftheopenproblems,withadiscussiononthepossibilitythatsomemesonsarenotquark-antiquarkstates.
Keywords:charmedmesons,quarkonium,nonstandardquark/gluonstates
1.IntroductionObservationofalonglistofnewhadronshasbeenrecentlyreportedbyexperimentsate+e−andp¯pcolliders,byfixedtargetexperimentsandbyreanalysesofolddata.WecanuseLeporello’swordsinMozart’sDonGio-vanni:Madamina,ilcatalogo`equesto:aD∗sJ(2317),DsJ(2460),DsJ(2632),DsJ(2860),D∗0(2308),D′1(2440),hc,η′c,X(3872),X(3940),Y(3940),Z(3930),Y(4260),Υ(1D),B1,B2,Bs2,Θ(1540)+,Θc(3099),Ξcc(3518),...Notallthestatesinthelisthavebeenconfirmed(DsJ(2632),Θ(1540)+,Θc(3099))andthereforewecanignorethem.Otherstates(Ξcc(3518))arebaryons,deservingadedicatedanalysis,andmesonswithopen(B1,B2,Bs2)orhiddenbeauty(Υ(1D)),thatwedonotdiscusshere.Weonlyconsidermesonswithopenandhiddencharm.Thewealthofinformationcollectedinrecentyearsisimpressive:notonlythenumberofknownstateshasnearlydoubled,butafewexperimentalobservationsseemtochallengethecurrentpictureofmesonsassimplequark-antiquarkconfigurations.Therefore,itisimportanttosearchthesignaturesallowingustoassignagivenstatetoaparticularmultiplet,sothatthehintsofexoticstructurescanbeclearlyinterpreted.ThenextSectionsaredevotedtosuchFebruary2,20087:15WSPC-ProceedingsTrimSize:9inx6incolangelo˙qcd062adiscussion,consideringseparatelythecaseofopencharmmesons,whichatpresentcanbeclassifiedaccordingtoknownrules,andthatofhiddencharmstateswhereacoupleofmesonsseemtoescapesimpleclassificationschemes.b
2.MesonswithopencharmInQCD,forhadronscontainingasingleheavyquarkQandinthelimitmQ→∞,thereisaspin-flavoursymmetryduetothedecouplingoftheheavyquarkfromthedynamicsofthelightdegreesoffreedom(lightquarksandgluons).Therefore,itispossibletoclassifystatescontainingtheheavyquarkQaccordingtothetotalangularmomentumsℓofthelightdegreesoffreedom.Formesons,statesbelongingtodoubletswiththesamesℓ=s¯q+ℓ,withs¯qthespinofthelightantiquarkandℓtheorbitalangularmomentumrelativetotheheavyquark,aredegenerateinmassinthelargemQlimit.Incaseofcharm,D0,+andD∗0,+,DsandD∗sarethestatesinthesPℓ=1
mc
),andvanisheswhenmc→∞.
Forℓ=1therearetwodoubletswithsPℓ=12+,forℓ=2twootherdoubletswithsPℓ=32
−
,andsoon.The
spin-flavoursymmetryisimportantnotonlyforspectroscopy,butalsofortheclassificationofstrongdecaymodesandforevaluatingtherates,sincedecaysinvolvingheavymesonsbelongingtothesamedoubletsarerelated.Forexample,thedecaysofmesonsbelongingtothesPℓ=3
2−mesonoccurind−wave,
sothatthesestatesareexpected,ceterisparibus,tobenarrowerthanthestatesbelongingtothedoubletsPℓ=1
mQ
effectscanbeimportant
incaseofcharm:forexample,thetwo1+statesbelongingtosPℓ=1
2+doublets,duetothefinitecharmquarkmass,couldmixwithamixing
angleθctoprovidethephysicalaxialvectormesons.Sucheffectsmustbeinvestigatedonthebasisoftheexperimentalobservation.February2,20087:15WSPC-ProceedingsTrimSize:9inx6incolangelo˙qcd0632.1.c¯qmesons:D∗0(2308)andD′1(2440).Informationaboutbroadc¯qmesons,onescalarandoneaxialvectorcharmedmesonthatcanbeinterpretedasthestatesbelongingtothesPℓ=1u,c
Belle4Focus5D∗+0
M(MeV)Γ(MeV)2403±14±35
283±24±34
D′01M(MeV)Γ(MeV)2427±26±20±15384+107−75±24±702461+41−34±10±32290+101−79±26±36
2+c¯smesons(Ds0andD′s1),
forming,togetherwithDs1(2536)andDs2(2573),thesetoffourlow-lyingℓ=1states.However,themassesofD∗sJ(2317)andDsJ(2460)arebe-lowtheirrespectivethresholdsforstrongdecays,DKandD∗K,thereforethesmallwidthisnatural.Moreover,analysesofradiativetransitions,thatprobethestructureofhadrons,supportthec¯sinterpretationofthetwostates7,8.Forexample,byLight-ConeQCDsumrulesonecancomputethehadronicparametersd,g1,g2andg3governingtheD∗sJ(2317)→D∗sγand