Microstructure and properties of β-NiAl and its eutectic alloy with Cr and Mo additions
遗传性耳聋基因芯片在新生儿重症监护室筛查中的应用
·临床经验交流·遗传性耳聋基因芯片在新生儿重症监护室筛查中的应用李婷 彭薇 马宁 李昊 杨晓 （解放军总医院第七医学中心八一儿童医院 解放军总医院儿科医学部 出生缺陷防控关键技术国家工程实验室 儿童器官功能衰竭北京市重点实验室，北京 100700）【摘要】 目的 分析新生儿重症监护室（neonatal intensive care unit，NICU）遗传性耳聋基因检测结果，探讨遗传性耳聋基因芯片在NICU新生儿耳聋基因筛查中的应用价值。
方法 选择NICU中的3 728例新生儿，采用9项遗传性耳聋基因检测试剂盒（微阵列芯片法）对新生儿进行中国人群常见4种耳聋基因突变筛查。
结果 在3 728例NICU新生儿中，共检测到180例新生儿携带耳聋基因突变，总突变携带率为4.82%。
其中GJB2基因突变103例(2.76%)，GJB3 538 C>T位点突变8例（0.21%），SLC26A4基因突变58例（1.55%），线粒体12SrRNA基因突变7例（0.19%），GJB2基因176_191 del 16和235 del C位点复合杂合突变、GJB2基因235 del C位点和SLC26A4基因IVS7-2A>G位点双杂合突变各1例，GJB2基因235 del C位点和线粒体12SrRNA基因1555A>G位点双杂合突变2例。
结论 NICU新生儿为耳聋高危群体，耳聋基因筛查对预防耳聋尤其是药物敏感性耳聋具有重要价值。
【关键词】新生儿；耳聋基因；基因芯片；突变筛查Application of genetic deafness gene chip in neonatal intensive care unit for screeningLi Ting, Peng Wei, Ma Ning, Li Hao, Yang Xiao (BaYi Children’s Hospital, Seventh Medical Centerof Chinese PLA General Hospital; Department of Pediatrics, Chinese PLA General Hospital; NationalEngineering Laboratory for Birth defects prevention and control of key technology; Beijing Key Laboratoryof Pediatric Organ Failure, Beijing 100700, China)Correspondingauthor:YangXiao(Email:********************)【Abstract】Objective To analyze the genetic screening results of hereditary deafness in the neonatesof neonatal intensive care unit (NICU) and explore the clinical value of genetic deafness gene chip inhereditary deafness screening in NICU neonates. Methods This study enrolled 3 728 NICU neonates.Nine deafness-related gene mutations detection kit(microarray chip) were used to screen 4 common deafnessgene mutations in NICU neonates. Results In 3 728 NICU neonates, 180 cases had deafness genemutations (4.82%). Of these, 103 cases(2.76%)were GJB2 mutations, 8 cases(0.21%)were GJB3 538C>T mutations, 58 cases(1.55%)were SLC26A4 mutations, 7 cases(0.19%)were mtDNA 12SrRNA genemutations, 1 case was compound heterozygous mutations of GJB2 176_191 del 16/235 del C, 1 case wasGJB2 235 del C/SLC26A4 IVS7-2A>G double heterozygous mutations and 2 cases were of GJB2 235del C/ mtDNA 12SrRNA 1555A>G double heterozygous mutations. Conclusion Because NICUneonates are at high risk of deafness, deafness gene screening is of great value in preventing deafness,especially drug-sensitive deafness.【Key words】Neonate; Deafness gene; Microarray gene chip; Mutation screenDOI：10.3969/j.issn.2095-5340.2020.04.010基金项目：国家重点研发计划（2018YFC1002701）通信作者：杨晓（Email：********************）耳聋是新生儿最常见的出生缺陷之一，在新生儿中的发病率为 1‰～3‰，每年约有超过 3万例耳聋新生儿出生［1］。
广西毛茛科植物新记录属--尾囊草属
广西毛茛科植物新记录属--尾囊草属谭卫宁;梁添富;罗柳娟;谭慎;黄俞淞;刘静【期刊名称】《广西植物》【年(卷),期】2017(037)007【摘要】该文报道了中国广西毛茛科(Ranunculaceae)植物新记录属--尾囊草属(Urophysa Ulbr.).该属为中国特有属,原记载分布于四川东部、贵州、湖北西部、湖南北部和广东,在广西木论国家级自然保护区的发现表明了亚热带喀斯特地貌植物区系广泛的联系性.文中还提供了尾囊草 [U.henryi (Oliv.) Ulbr.]的形态描述和图片.%Urophysa Ulbr., a newly recorded genus of Ranunculaceae from Guangxi, China is reported.This genus is endemic to China, its original distribution is in eastern Sichuan, Guizhou, western Hubei, northern Hunan and Guangdong.Discovering this genus from Mulun National Nature Reserve indicates extensive relationship among subtropical karst floras.Detailed morphological description and field photos of U.henryi (Oliv.) Ulbr.are provided.【总页数】4页(P926-929)【作者】谭卫宁;梁添富;罗柳娟;谭慎;黄俞淞;刘静【作者单位】广西木论国家级自然保护区管理局, 广西环江 547100;环江毛南族自治县林业局, 广西环江 547100;广西木论国家级自然保护区管理局, 广西环江547100;环江毛南族自治县林业局, 广西环江 547100;广西壮族自治区中国科学院广西植物研究所, 广西桂林 541006;广西壮族自治区中国科学院广西植物研究所, 广西桂林 541006【正文语种】中文【中图分类】Q949.7【相关文献】1.尾孢菌属·假尾孢属及钉孢属真菌7个吉林省新记录种 [J], 翟凤艳;郭英兰;刘英杰;李玉2.广西唇形科一新记录属——喜雨草属 [J], 莫佛艳;蒙丽;冯慧喆;苏宇乔;薛跃规3.陕西省百合科一新记录属——独尾草属 [J], 王勇;杨培君4.陕西毛茛科新分布属——尾囊草属 [J], 殷越阅;胡榜文;凡荣;王文章;周仕俊;柯云;李丛斌5.云南五种毛茛科植物的核形态研究兼论星果草属和鸡爪草属的系统位置(英文) [J], 杨亲二;龚洵;顾志建;武全安因版权原因，仅展示原文概要，查看原文内容请购买。
农村水环境政策与污染的时空迁移特征及关系
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environment policies and pollution[J].Journal of Agro-Environment Science ,2024,43（4）：886-895.农村水环境政策与污染的时空迁移特征及关系万欣，张怡*，苏鹏程，骆心怡，林佳欣（河海大学商学院，南京211100）Spatiotemporal migration patterns and relationships between rural water environment policies and pollutionWAN Xin,ZHANG Yi *,SU Pengcheng,LUO Xinyi,LIN Jiaxin（School of Business,Hohai University,Nanjing 211100,China ）Abstract ：In order to reveal the temporal and spatial evolutional relationships between rural water pollution and the corresponding governance policies,the migration paths of gravity centers for the two indicators were plotted based on measurements of policy strength and pollution intensity.Then,various provinces were classified into different “policy-pollution ”types by using the Shapley value decomposition method,and the causal relationship between policy and pollution under each type was analyzed based on the Granger causality test method.The results showed that both the gravity centers of policy and pollution located in southeast China,but their migration paths were not aligned with each other.The former exhibited a “south-west-north-east ”directional trend,whereas the latter consistently demonstrated a propensity for migration towards the south.In terms of the link between policy and pollution,it was observedthat the reduction in pollution intensity contributed to an enhancement in policy strength in “growth-reduced ”type provinces.However,the drivers for this enhancement differ between eastern and western provinces.As for provinces classified as “reduced-reduced ”,the decrease in policy effectiveness was found to be a result of reduced pollution intensity;however,there were instances of policy deviationevident in specific dimensions of pollution.At last,the provinces falling under the "pollution growth"category did not exhibit Granger causality between policy and pollution.Therefore,it was recommended that future policy-making incorporates its association with pollution outcomes and enhances the precision,synergy,and foresight of policies,which is beneficial to the elevation of efficiency and effectiveness of policy formulation.Keywords ：rural water pollution;gravity center migration;policy strength;pollution intensity;“policy-pollution ”type收稿日期：2023-04-13录用日期：2023-08-03作者简介：万欣（1985—），女，吉林通化人，博士，副教授，主要从事城乡可持续建设与治理研究。
尾凤蝶属昆虫研究概况
尾凤蝶属昆虫研究概况作者：曾全易传辉和秋菊陈焱赵健来源：《湖北农业科学》2014年第19期摘要：对尾凤蝶属（Bhutanitis）昆虫的研究主要集中在形态描述和分类方面，其次是生物学特性研究，仅有少数涉及到分子生物学和保护生物学等方面。
分子生物学和保护生物学研究将是今后该属昆虫的研究重点。
关键词：昆虫；凤蝶科（Papilionidae）；尾凤蝶属（Bhutanitis）；濒危中图分类号：Q969.42 文献标识码：A 文章编号：0439-8114（2014）19-4516-04DOI：10.14088/ki.issn0439-8114.2014.19.002The Researches Review of Genus Bhutanitis AtkinsonZENG Quan1， YI Chuan-hui2， HE Qiu-ju1， CHEN Yan2， ZHAO Jian1（1. Key Laboratory of Forest Disaster Warning and Control in Yunnan Province， College of Forestry， Southwest Forestry University， Kunming 650224， China； 2. Yunnan Academy of Forestry， Kunming 650201， China）Abstract： Studies of Genus Bhutanitis Atkinson were mainly focused on morphological description and classification in the past years. Some studies were on biological characteristics. A few studies were on molecular biology and conservation biology. More studies should be focused on the molecular biology and conservation biology in the future.Key words： insect；Papilionidae； Bhutanitis； endangered尾凤蝶属（Bhutanitis）属鳞翅目（Lepidoptera）凤蝶科（Papilionidae）锯凤蝶亚科（Zerynthiinae）昆虫，为典型高山种类。
厦门同安湾下潭尾人工红树林湿地小型底栖动物群落结构
厦门同安湾下潭尾人工红树林湿地小型底栖动物群落结构陈昕韡;李想;曾佳丽;谭文娟;周细平;洪万树;蔡立哲【摘要】为研究厦门同安湾下潭尾人工红树林湿地小型底栖动物的群落结构,于2014年在下潭尾人工红树林湿地5个取样站进行了4个季节小型底栖动物定量取样,共获取了9个小型底栖动物类群,分别为自由生活海洋线虫、底栖桡足类、寡毛类、多毛类、涡虫类、有孔虫类、介形类、双壳类、星虫类,还有少许未定类群.其中,自由生活海洋线虫是优势类群,占总丰度的91.75％.下潭尾人工红树林湿地小型底栖动物平均丰度为(441.3±61.0) ind/(10 cm2),平均生物量为(555.8±104.6) μg/(10 cm2).单变量双因素方差分析(two-way ANOVA)表明:不同季节之间小型底栖动物丰度和生物量有极显著差异;不同取样站之间小型底栖动物丰度无显著差异,生物量有显著差异.小型底栖动物群落的类群均匀度指数(J')、多样性指数(H')和优势度指数(λ)的最高值均出现在光滩取样站.Pearson相关性分析表明:小型底栖动物的个体数与底温呈极显著负相关、与底盐呈显著负相关;夏、秋两季小型底栖动物的类群数以及夏季小型底栖动物丰度均与底盐呈显著相关.上述结果完善了我国人工红树林湿地小型底栖动物物种和生境多样性资料库,为滨海湿地公园管理、滩涂生态修复和红树林湿地管理提供了基础资料.%In order to study the community structure of meiofauna in artificial mangrove wetland of Xiatanwei located in Tong'an Bay,the meiofauna was quantitatively investigated at five stations in the four seasons of 2014.Nine meiofaunal groups were observed,including free-living marine Nematoda,benthic Copepoda,Oligochaeta,Polychaeta,Turbellaria,Foraminifera,Ostracoda,Bival via and Sipuncula.Among them,free-living marine Nematoda was the dominant group,accounting for 91.75 ％ of the total abundance.Theaverage abundance and biomass of meiofauna were (441.3 ± 61.0) ind/(10 cm2) and (555.8 ± 104.6) μg/(10 cm2),respectively.Univariate two-way ANOVA showed that there were highly significant differences in meiofauna abundance and biomass among seasons,and significant differences in biomass but not in meiofauna abundance among stations.The highest values of evenness index (J'),Shannon-Wiener index (H') and dominance index (λ) all appeared in the mudflat station.Meanwhile,Pearson correlation analysis indicated that temperature and salinity were the factors influencing the group number of meiofauna,and salinity was a crucial element that affected the abundance of meiofauna in summer.This study provides new data bank of meiofauna in artificial mangrove areas in China and supplies basic data of coastal wetland park management,intertidal zone ecological restoration and coastal mangrove wetland management.【期刊名称】《厦门大学学报（自然科学版）》【年(卷),期】2017(056)003【总页数】8页(P351-358)【关键词】小型底栖动物;群落;人工红树林湿地;同安湾;下潭尾【作者】陈昕韡;李想;曾佳丽;谭文娟;周细平;洪万树;蔡立哲【作者单位】厦门大学环境与生态学院,福建厦门361102;厦门大学环境与生态学院,福建厦门361102;厦门大学环境与生态学院,福建厦门361102;厦门大学环境与生态学院,福建厦门361102;厦门大学嘉庚学院环境科学与工程学院,福建漳州363105;厦门大学海洋与地球学院,福建厦门361102;厦门大学环境与生态学院,福建厦门361102【正文语种】中文【中图分类】Q178.1同安湾位于福建省东南部沿海厦门岛北侧,东接翔安区,西、北部分别为同安区和集美区,南部为厦门岛,包括东咀港和浔江港海域[1]．下潭尾海域位于同安湾顶,属于厦门市翔安区范围．有关同安湾红树林湿地底栖动物的研究,开始于集美凤林老红树林湿地(因城市建设已被填埋)大型底栖动物体内多环芳烃的研究[2]和大型底栖动物群落的研究[3],随后比较了同安湾潮间带红树林生境与非红树林生境的大型底栖动物群落[4],并进行了同安湾红树林树上大型底栖动物生态分布的研究[5]．同安湾红树林湿地小型底栖动物的研究开始于2008年,主要报道了凤林红树林湿地自由生活海洋线虫群落[6],还比较了同安湾两处红树湿地的小型底栖动物丰度[7]．对同安湾潮下带底栖动物的研究较早：2000年,方少华等[8]报道了浔江湾小型底栖生物数量;2007年,林俊辉等[9]报道了同安湾春季大型底栖生物的群落结构特征．小型底栖动物作为连接有机碎屑、初级生产和水层-底栖耦合的重要环节,是许多经济鱼、虾和贝类幼体时期的优质饵料[10];同时,小型底栖动物也是沉积物中有机碎屑的开发者和底栖细菌、微藻的主要消耗者,其摄食率大体与微生物生产量持平,调节微生物生产过程[11],在海洋生态系统中起着重要作用．2011年,厦门市在下潭尾海域启动了以红树林为主题的生态湿地公园建设,种植红树林42.8 hm2．本研究拟了解新的人工红树林湿地小型底栖动物动物群落结构以及主要环境因子对其的影响,旨在为我国人工红树林湿地建设和红树林湿地生态恢复提供基础资料．1.1 研究区域概况厦门市下潭尾滨海生态湿地公园位于厦门市翔安区下潭尾片区,南北以现有海岸线为界,东至塘厝水闸坝堤,西至东坑湾水道东侧口与赵厝岸线西侧连线,公园总规划面积400 hm2,其中滩涂面积125 hm2．已开工建设的下潭尾滨海生态湿地公园计划构建适宜红树林生长的人工滩涂岛5个,面积约44.8 hm2,滩涂治理面积15.5 hm2[12]．红树林种植工程已于2012—2013年基本完成,种植树种以秋茄(Kandelia candel)为主,还包括桐花树(Aegiceras corniculatum)、白骨壤(Avicennia marina)和无瓣海桑(Sonneratia apetala)等．本研究在下潭尾人工红树林湿地布设A、B、C、D、E共5个取样站(图1),并于2014年2月(冬季)、5月(春季)、8月(夏季)、11月(秋季)进行了4个季节小型底栖动物的生态调查,每个取样站各取5个平行样．A、B、C、E取样站位于人工红树林内,D取样站位于光滩．1.2 样品采集和处理方法小型底栖动物的样品采集在低潮时进行．选取表面较平整且未受扰动的区域作为采样点,用内径为2.9 cm的注射器改造而成的采样管取样,取样深度约为9 cm．将采样管中的沉积物转移到250 mL塑料广口瓶,然后加入5%(体积分数)的甲醛溶液进行固定,固定后的所有样品带回实验室分选．分选前,先将样品摇匀;然后,将0.500 mm和0.042 mm孔径的网筛叠放,将摇匀的样品倒入网筛,用自来水冲洗样品,除去样品中的黏土、粉砂及其他杂质;接着,将0.042 mm孔径的网筛上残留的沉积物样品用密度为1.15 g/mL的Ludox-TM硅胶液分次转移到离心管中,Ludox-TM硅胶液的体积约为沉积物的3～4倍．混匀后,将样品以5 000 r/min的转速离心5 min．取悬浮液,向残留沉积物的离心管中再次加入Ludox-TM硅胶液重复离心1次．合并2次离心所得的悬浮液,倒入0.042 mm孔径的网筛,用自来水冲洗去除Ludox-TM硅胶液．之后,将样品转移到带平行线的培养皿中,在SMZ-168体式显微镜下对小型底栖动物进行分类、计数,将计数完的小型底栖动物保存于75%(体积分数)的乙醇溶液中以待后续操作．小型底栖动物的丰度(ind/(10 cm2),单位面积个体数)由直接计数得到．小型底栖动物的生物量(μg/(10 cm2),单位面积干重)测定方法采用换算法,即通过小型底栖动物各类群的个体平均干重乘以相应类群的丰度得到．自由生活海洋线虫(free-living marine Nematoda,简称线虫)、底栖桡足类(benthic Copepoda，简称桡足类)、寡毛类(Oligochaeta)、多毛类(Polychaeta)和介形类(Ostracoda)平均个体干重的测定方法以《海洋调查规范第6部分:海洋生物调查GB/T 12763.6—2007》[13]为依据,上述5个类群之外其他类群的平均个体干重参照Jario[14]、Widbom[15]和张志南等[16]的研究结果,见表1．2.1 小型底栖动物的类群组成2014年2—11月的4个季节中,共在下潭尾人工红树林湿地采集到9个类群的小型底栖动物,分别为线虫、桡足类、寡毛类、多毛类、涡虫类、有孔虫类、介形类、双壳类和星虫类,还有少许未定类群归为其他类．采集到的小型底栖动物中,线虫丰度百分比最高(91.75%),双壳类丰度百分比最低(0.02%),其他7个类群按丰度百分比由高到低依次为:桡足类(4.52%)、寡毛类(2.13%)、有孔虫类(0.57%)、涡虫类(0.45%)、多毛类(0.27%)、星虫类(0.17%)、介形类(0.05%)，另其他类占0.07%．分析各取样站的不同类群丰度百分比,结果如图2所示:在5个取样站均有发现线虫、桡足类、寡毛类、多毛类、涡虫类、有孔虫类和星虫类7个小型底栖动物类群,其中线虫的丰度百分比在各取样站均达到了80%以上;A、D和E取样站丰度百分比居第二位的是桡足类,而B、C取样站为寡毛类．A取样站共采集到8个小型底栖动物类群,除上述7个共有类群外,增加了其他类;在B、C、D取样站均采集到9个小型底栖动物类群,除上述7个共有类群外,增加了介形类和双壳类,还有少许未定类群即归为其他类;E取样站获得8个小型底栖动物类群,除上述7个共有类群外,增加了介形类．利用PRIMER 5.0软件对下潭尾人工红树林湿地小型底栖动物的类群组成进行多维尺度分析(multi-dimensional scaling,MDS)．分析结果(图3)显示:Stress=0.09,表明图形中显示的样本间关系可信;从季节上看,冬季小型底栖动物的类群组成最相似,夏季的差异最大．2.2 小型底栖动物的平均丰度和平均生物量分析各季节各取样站的小型底栖动物丰度,结果如图4所示:丰度最高值出现在冬季的E取样站,为(855.9±325.1) ind/(10 cm2);最低值则出现在夏季的D取样站,为(190.3±60.1) ind/(10 cm2)．从全年平均值上看：E取样站小型底栖动物的丰度最高,为(514.0±282.5) ind/(10 cm2);B、C、A取样站依次递减,分别为(471.5±254.1) ind/(10 cm2),(464.7±182.2) ind/(10 cm2)和(388.6±129.1) ind/(10 cm2);D取样站最低,为(368.0±164.0) ind/(10 cm2)．春季小型底栖动物的丰度最高值出现在B取样站,夏季丰度最高值出现在C取样站,春、夏两季丰度最低值均出现在D取样站;秋、冬两季丰度最高值均出现在E取样站,秋季最低值出现在B取样站,冬季最低值出现在A取样站．单变量双因素方差分析(two-way ANOVA)结果表明：不同季节间小型底栖动物的丰度呈极显著差异(p<0.01),不同取样站间小型底栖动物的丰度无显著差异(p>0.05),季节×取样站间小型底栖动物的丰度无显著差异(p>0.05)．分析各季节各取样站的小型底栖动物生物量,结果如图5所示:生物量的最高值出现在秋季的E取样站((1 015.6±33.5) μg/(10 cm2)),最低值出现在夏季的B取样站((168.6±26.3) μg/(10 cm2))；从全年平均值上看：E取样站小型底栖动物的生物量最高,为(709.9±315.9) μg/(10 cm2);B、C、D取样站依次递减,分别为(575.3±311.8) μg/(10 cm2),(548.8±258.8) μg/(10 cm2)和(526.1±211.4)μg/(10 cm2);A取样站最低,为(419.1±106.3) μg/(10 cm2)．春季小型底栖动物的生物量最低值出现在D取样站,最高值出现在B取样站;夏季生物量最低值出现在B取样站,秋、冬两季最低值均出现在A取样站,夏、秋、冬三季最高值均出现在E取样站．Two-way ANOVA结果表明：不同季节间小型底栖动物的生物量呈极显著差异(p<0.01),不同取样站间小型底栖动物的生物量呈显著差异(p<0.05),季节×取样站间小型底栖动物的生物量无显著差异(p>0.05)．2.3 小型底栖动物类群的多样性利用PRIMER5.0软件计算下潭尾人工红树林湿地各季节各取样站小型底栖动物的类群数(S)、个体数(N)、类群丰富度指数(d)、均匀度指数(J′)、香农-威纳多样性指数(H′)和优势度指数(λ)．计算结果如表2所示:d的最高值出现在秋季的B取样站(0.825)；J′、H′和λ的最高值均出现在夏季的D取样站,分别是0.443，0.891和0.330；d、J′、H′和λ的最低值均出现在夏季的B取样站,分别是0.134，0.104，0.069和0.018．2.4 小型底栖动物类群与环境因子的相关性将下潭尾人工红树林湿地4个季节小型底栖动物的类群数和丰度与底温、底盐进行Pearson相关性分析,结果(表3)表明:夏季的类群数与底盐呈显著负相关(p<0.05);秋季的类群数与底盐呈显著正相关(p<0.05);夏季的丰度与底盐呈显著正相关(p<0.05);其他各参数之间无显著相关性．对下潭尾人工红树林湿地小型底栖动物的类群的多样性参数与底温、底盐进行Pearson相关性分析,结果(表4)表明:个体数与底温呈极显著负相关(p<0.01),与底盐呈显著负相关(p<0.05)；其余各参数之间无显著相关性(p>0.05)．3.1 底温和底盐对小型底栖动物的影响小型底栖动物的分布受物理、化学和生物方面多种因素的影响,如气温、沉积物粒度、泥温、底盐、叶绿素a含量、水深以及自身繁殖特点等．Palmer等[17]的研究显示小型底栖动物的生殖和发育都与温度呈正相关;吴辰[18]研究了湛江高桥红树林的小型底栖动物,发现春、夏、秋三季小型底栖动物丰度与温度有显著相关性;卓异[19]发现泉州湾潮间带红树林区夏季小型底栖动物的丰度与温度有极显著负相关性;而本研究中各季节小型底栖动物的丰度与底温均无显著相关性,这与上述学者的研究结果不同．Palmer等[17]认为冬季水体的底温降到全年较低水平,在经过秋季小型底栖动物的丰度高峰期后,沉积物中有机质消耗殆尽,因此小型底栖动物的丰度为全年较低，吴辰[18]在湛江高桥的研究结果支持以上结论.但本研究的结果却是冬季小型底栖动物的丰度较高,与文献[19-21]的研究结果一致．这可能是因为影响小型底栖动物丰度和分布的因素除了温度外,还有盐度、光照、降水量等．同时,气候条件、红树植物类型、人为扰动程度和沉积物等因素的差异也会造成小型底栖动物丰度的差异．Ingole等[22]研究了盐度对热带河口砂质潮间带小型底栖动物结构的影响,结果表明小型底栖动物的丰度波动与盐度波动有显著相关性,无脊椎动物群落分布与不同的盐度区域有直接的关联性．本研究中夏、秋两季小型底栖动物的类群数与底盐有显著相关性,其中夏季小型底栖动物丰度与底盐呈显著正相关．卓异[19]发现泉州湾潮间带夏季小型底栖动物丰度与盐度呈显著正相关,其他季节各参数与盐度无显著相关性;吴辰[18]在湛江高桥红树林区发现春季小型底栖动物丰度与盐度呈极显著负相关,其他季节均无显著相关性．Ingole等[22]的研究地点为热带的河口砂质潮间带,但上述研究区域为亚热带红树林区.Barbara等[23]的研究显示,砂质沉积物中沉积环境异质性高,许多物种生活于砂间间隙,环境变化时小型底栖动物能迅速响应．因此,在砂质潮间带小型底栖动物对于盐度的变化较为敏感,而由于大多数红树林是生长在细质的淤泥质滩涂上,且一般红树林土壤是初生土壤,土壤由粉粒和黏粒组成,含有大量有机质[24],与砂质潮间带有较大不同,所以红树林区小型底栖动物与盐度的相关性有待进一步研究．3.2 不同红树林区小型底栖动物群落结构的差异由于红树林中具有丰富的单宁酸和有机质,红树林中的小型底栖动物与非红树林区有着显著的差异[25],且小型底栖动物在红树林生态系统中起着非常重要的作用,世界各地的底栖生物学家相继在不同红树林区域开展了研究工作．小型底栖动物的分布很广泛,在海洋任何沉积物中几乎都有分布,但是不同区域和不同生境,其密度、类群组成、生物量和多样性都有非常大的区别[26]．我国研究红树林区小型底栖动物的科研人员相对较少,现有的研究区域主要集中在福建、海南、深圳和香港等地；国际上,近10年关于红树林区小型底栖动物的报道主要集中在越南、古巴、印度、加勒比海、红海和西里伯斯海．lafsson[27]、Armenteros等[28]和Sabine[29]的早期研究表明：红树林小型底栖动物主要包括线虫、桡足类、多毛类、寡毛类、猛水蚤类、介形类、动吻类、原足类、涡虫类、纽虫类、海螨类、轮虫类这12 个类群,其中线虫是较主要的类群,其次是桡足类．但近10年国际上对红树林区小型底栖动物的研究[25,28,30]显示,各地区小型底栖动物的类群数为5～12个,除了上述12个类群,还发现了有孔虫类、双壳类、纤毛虫类、刺胞动物、颚口动物、昆虫类、苔藓虫类、肉鞭毛虫类、被囊类、腹足类、甲壳类这11个类群,类群数相对早期研究有了较大的增加．在中国红树林区域的研究中,同样发现了更多的小型底栖动物类群．目前,仅福建红树林区报道的小型底栖动物类群就有20个,分别是线虫、桡足类、多毛类、寡毛类、介形类、动吻类、海螨类、轮虫类、原足类、纽虫类、昆虫类、枝角类、涡虫类、缓步类、有孔虫类、双壳类、原生动物、星虫类、端足类和腹足类[19-21,31]．其中,曹婧[20]在漳江口红树林区发现小型底栖动物14类,为福建已报道的区域中类群数较多的；本研究在下潭尾人工红树林湿地鉴定出小型底栖动物9类,低于漳江口红树林地区；而周细平[31]在集美凤林红树林和翔安山后亭红树林均只发现小型底栖动物5类,为福建已报道的区域中类群数较少的．Alongi[32]研究发现砂质海滩小型底栖动物的丰度一般可达(1 000～8 000) ind/(10 cm2),而红树林区则普遍低于500 ind/(10 cm2)．但是许多研究显示红树林区小型底栖动物丰度高于500 ind/(10cm2)．本研究在同安湾人工红树林湿地获得的小型底栖动物平均丰度为(441.3±61.0) ind/(10 cm2),对比国内报道的(397.6～2 229.9) ind/(10cm2)[6,18-21,31,33]及国外近10年报道的越南、古巴、印度、加勒比海、红海和西里伯斯海等地区的(108.6～2 474) ind/(10 cm2)[25,28,30],处于较低水平．周细平[31]在集美凤林人工红树林区和翔安山后亭人工红树林区只发现小型底栖动物类群5个,远低于本研究区域的9个，但其小型底栖动物年平均丰度(分别是(1 548±512) ind/(10 cm2)和(892±19) ind/(10 cm2))均高于本研究区域((441.3±61.0) ind/(10 cm2))．这可能是因为本研究区域内红树的树龄均不超过2龄,属于新生红树林区,红树凋落物较少,红树林的集约度和郁闭度均低于成熟红树林区,小型底栖动物所处的生态系统尚未完全成熟,为不同类群的生长繁殖提供了可能,同时也制约着小型底栖动物各类群数量的单一增长．另外,有报道指出红树林水域富营养化会造成底栖生物多样性及种类数下降[34]；且周边居民频繁采挖红树林中的经济种类,扰动沉积物,影响红树林的生境,同样会导致小型底栖动物的丰度和多样性降低．物种所处环境对其生理机能、分布及种群密度都有极大影响[22]．大量资料表明,影响小型底栖动物群落的因素很多,包括气候条件、人为扰动、底质类型、温度、盐度、pH 值、有机物以及一些无机元素的含量等[35],因此造成不同红树林区小型底栖动物群落结构及丰度差异的原因是复杂多样的,难以归结为某种具体的原因,相关研究亟待开展．本研究通过对厦门同安湾下潭尾人工红树林湿地的小型底栖动物定量采集所获数据进行分析,发现影响人工红树林湿地小型底栖动物群落结构的因素复杂多样,且可能与树龄存在一定的关系.这些结果完善了我国人工红树林湿地小型底栖动物物种和生境多样性资料库,为滨海湿地公园管理、滩涂生态修复和红树林湿地管理提供了基础资料．【相关文献】[1] 鲍晶晶,蔡锋,任建业,等.厦门同安湾地貌特征研究[J].应用海洋学学报,2013,32(4):499-508.[2] 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鱼类尾垂体的研究进展(修订版)
鱼类尾垂体的研究进展孙树彬、张嘉慧、张丽君(生命科学学院生物科学 )摘要:尾垂体是指在硬骨鱼类脊髓末端（终枝前）形成的一种神经垂体[1]，也称神经性脊髓垂体（neurohypophysisspinalis）。
相当于尾神经分泌系统的贮藏释放部分，是由神经分泌细胞的轴突及其末端、神经胶质细胞和上衣细胞及该等细胞的突起、包裹它们的硬膜以及网眼状血管所构成的。
[2]关键词:尾垂体内分泌结构神经分泌颗粒激素生理作用尾垂体是鱼类中特有的一种内分泌腺体。
早在一百余年前欧洲动物学者Arsajy，1813，Srerres，1826，Weber，1827已经提出。
他们在研究鱼类尾部脊髓末端构造时，首先在鲤鱼中发现有一疣状物体，以后在其他鱼类中也有见到同样构造。
之后动物学者Verne，1914，Favaro，1926，，进一步研究尾垂体的显微组织构造，他们根据县委构造的组织成分，认为这一构造是一个腺体而且与脑垂体的神经垂体部分有相似之处，因此采用尾垂这个称号。
[23]本文将从几个方面综述有关鱼类尾垂体的研究工作与进展。
一、尾垂体的位置及其所处的环境尾垂体是指在硬骨鱼类脊髓末端形成的一种神经垂体，鱼类尾部脊髓下方的一个神经内分泌结构，也称神经性脊髓垂体。
实际上尾垂体与巨型细胞的空间位置是接近的。
二、尾垂体的组织结构及功能2。
1尾垂体的组织结构尾垂体的形态及功能都同哺乳动物的神经垂体相似。
许多真骨鱼都有这种结构，只是大小不一，在各种鱼类之中尾垂体有共同点，即腺体前段靠近脊髓处较宽，后端接近终丝出则较狭长。
此外包围着脊髓及尾垂体的膜上分布着黑色素细胞。
组织学上，尾垂体这个结构与哺乳动物脑下垂体后叶(神经垂体)都是神经内分泌器官。
在这些鱼的尾部脊髓内有神经分泌细胞，它们的轴突延伸到尾垂体，将其分泌物转送到尾垂体，再由此释放入血。
尾垂体根据外形可以分为单个型和两叶型，单个型中分为圆球型和长圆型，两叶型则分为表面有细致突起者和表面有分段或小叶者两个副型。
资源昆虫学-昆虫的主要类群
陕西理工学院
Shaanxi University of Technology
昆虫的主要类群 4.缨尾目Thysanura
石蛃的复眼大，左右相接，体隆起。生活在山地岩石上及海 岸岩礁上。体色通常与栖息环境相似，不易被发现，如果用 手在岩石上挥动，则可见有石蛃在爬动，并会跳。
衣鱼复眼小而左右远离或退化，体扁平。多生活于室内，在 衣服、书、画等收藏品中时常可以看到，有时会在墙上爬， 是书籍与字画的一害。
2001年6月，一位研究生Zompro访问了英国自然历史博物馆。
管理员给他看了一只1950年采于坦桑尼亚的标本。这只标
本很像是一种竹节虫，但是半个世纪以来，没有人知道这是
什么。没过几天，一位琥珀收集者又寄给了Zompro一只被
琥珀包裹住的小虫，和那只标本很像。随后，Zompro又在
柏林自然博物馆发现了类似标本，并请另外两位昆虫学家
陕西理工学院
Shaanxi University of Technology
昆虫的主要类群
14. 螳螂竹节目（螳修目）Mantophasmatodea 1914年，蛩蠊目Grylloblattodea被发现。从这以后，所有新发
现的昆虫，都成为了三十来个目里面的种类。2001年，昆 虫增加了一个新的目——螳螂竹节目 (Mantophasmatodea)。
Shaanxi University of Technology
昆虫的主要类群
10. 缺翅目Zoraptera
由于最初发现的缺翅虫均为缺翅型，所以定名为缺翅目。 1920年，A. N.考迪尔在美洲得到这类昆虫的有翅类型。 从此，人们明确了缺翅目昆虫有缺翅和有翅两个类型。
中华缺翅虫（Zorotypus sinensis ）墨脱缺翅虫Zorotypus medoensis。 zoological subject
CT80级非调质连续油管用钢的组织和性能控制_李明扬
第33卷第5期2012年5月材料热处理学报TRANSACTIONS OF MATERIALS AND HEAT TREATMENTVol ．33No ．1May2012CT80级非调质连续油管用钢的组织和性能控制李明扬1，刘雅政1，周乐育1，袁付春1，朱涛2，饶添荣2（1.北京科技大学材料科学与工程学院，北京100083；2.马钢股份有限公司技术中心，安徽马鞍山243000）摘要：通过两种成分非调质CT80连续油管用钢现场生产板卷工艺组织性能对比，分析了冷却速度、卷取温度、Mo 和Nb 元素含量等工艺参数对实验钢组织性能的影响。
结果表明：当冷却速度由52ħ/s 提高到69ħ/s 后，铁素体形态为针状铁素体，实验钢屈服强度提高25MPa ；抗拉强度提高30MPa 。
实验钢在530ħ卷取时，组织中出现了3%的珠光体组织，抗拉强度低于性能指标10MPa 。
而在400ħ卷取时，组织中出现了3%的块状马氏体组织，使得屈服强度低于性能指标20MPa ；抗拉强度提高到690MPa 。
Mo 元素含量提高，促进针状铁素体转变，实验钢淬透性提高，有利于获得M /A 岛组织，保证获得高强度低屈强比性能。
Nb 元素含量提高，细晶强化和析出强化作用更明显。
关键词：连续油管；针状铁素体；显微组织中图分类号：TG142.4文献标志码：A文章编号：1009-6264（2012）5-0101-07Microstructure and properties control of non-quenched and tempered CT 80grade coiled tubing steelLI Ming-yang 1，LIU Ya-zheng 1，ZHOU Le-yu 1，YUAN Fu-chun 1，ZHU Tao 2，RAO Tian-rong 2（1.School of Materials Science and Engineering ，University of Science and Technology Beijing ，Beijing 100083，China ；2.Technology Center of Maanshan Iron and Steel Co Ltd ，Maanshan 243000，China ）Abstract ：The non-quenched and tempered CT80grade coiled tubing steels with different composition were designed.Effects of cooling rate ，coiling temperature and Mo and Nb content on microstructure and mechanical properties of the non-quenched and tempered CT80steels were investigated.The results show that when cooling rate increases from 52ħ/s to 69ħ/s ，acicular ferrite is obtained ，and yield strength and tensile strength of the tested steel increase by 25MPa and 30MPa ，respectively.When the coiling temperature is 530ħ，pearlite is observed in the microstructure of the tested steel ，and its tensile strength decreases by 20MPa and yield strength increases to 690MPa.The increase of Mo content is benefit of the formation of acicular ferrite and hardenability of tested steel ，and martensite-austenite （M /A ）islands increase in the microstructure.As the content of element Nb increases ，it is favourable of grain refining sterngthening and precipitation strengthening of the steel.Key words ：coiled tube ；acicular ferrite ；microstructure收稿日期：2011-06-09；修订日期：2011-08-11作者简介：李明扬（1986—），男，博士研究生，主要从事连续油管用钢产品开发与质量控制研究，电话：010-********，E-mail ：louis_926@163．com 。
重熔与时效工艺对ZL101铝合金组织与抗拉强度的影响
收稿日期:2006 10 16; 修订日期:2006 10 18基金项目:内蒙古工业大学校基金资助项目,项目编号(004 20064879)作者简介:李 峰(1974 ),山西灵丘人,讲师,工学硕士.研究方向:稀土钢与铝合金材料.Email:yangxiaohuilieng@铸造技术F OU N DRY T ECH NO LO GY Vo l.27No.12Dec.2006重熔与时效工艺对ZL101铝合金组织与抗拉强度的影响李 峰,张 娟,史志铭(内蒙古工业大学材料科学与工程学院,内蒙古呼和浩特010051)摘要:ZL101铝合金重熔后,浇注时间和浇注位置对其组织与性能影响很大。
从ZL 101铝合金不同浇注时间、不同浇注的位置取样,对铸态和时效后的试样进行抗拉强度性能测试,用光学显微镜观察其微观组织,研究重熔与时效工艺对ZL 101铝合金组织与性能的影响规律。
结果表明,在浇注过程中,试样的晶粒先发生粗化,随着浇注时间的延长,晶粒又发生细化。
其抗拉强度也是先降低而后又升高。
随着浇注位置的变化,由下向上晶粒逐渐粗化,共晶硅的分布逐渐变得不均匀,且抗拉强度逐渐降低。
合金的时效与铸态的组织、性能的变化规律一致。
关键词:重熔;时效;浇注时间;浇注位置中图分类号:TG146.2+1 文献标识码:A 文章编号:1000 8365(2006)12 1326 03Effect of Remelting and Aging Process on Microstructureand Tensile Strength of ZL 101Al AlloyLI Feng,ZHANG Juan,SHI Zhi ming(School of Material Science and Engineering,Inner Mongolia University of Technology,Huhhot 010051,China)Abstract:Pou ring time and pourin g locations have obviou s effects on microstru ctu res and properties after ZL101Al alloy is remelted.Samples were cu t from ZL101Al alloy with different pou ring locations an d different pouring time.The tensile stren gth of sam ples at as cast and aged state was tested and th eir microstructu res were observed with optical m icroscope.Effectof remelting and agin g process on the microstru ctures an d properties of ZL101Al alloy were investigated .The resu lts show that grain s are coarsened at the early stage of casting,th en refin ed with increase of the casting time.The ten sile stren gth decreases firstly,reach es the min imu m,an d then increases.The grain s become coarser gradu ally from the bottom to th e top with chan ge of pourin g location and the distribu tion of eutectic crystal Si becomes n on u niform,and the ten sile strength decreases gradu ally.The variation of microstru cture an d properties at the aged state has the sam e ten den cy as th at at the as cast state.Key words:R emelting;Aging;Pourin g time;Pou ring positionZL101合金目前被广泛应用于汽车、摩托车轮毂铸造和其它领域中,是一种很有发展前途的铝合金[1~5]。
粉末冶金热等静压方法制造的近净成形Ti
Trans. Nonferrous Met. Soc. China 30(2020) 3006−3015Microstructure and high-temperature mechanical properties of near net shaped Ti−45Al−7Nb−0.3W alloy by hot isostatic pressing processHui-zhong LI1,2,3, Yi-xuan CHE1, Xiao-peng LIANG1,2,3, Hui TAO1,Qiang ZHANG1, Fei-hu CHEN1, Shuo HAN1, Bin LIU21. School of Materials Science and Engineering, Central South University, Changsha 410083, China;2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;3. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education,Central South University, Changsha 410083, ChinaReceived 8 January 2020; accepted 31 July 2020Abstract: Near net shaped Ti−45Al−7Nb−0.3W alloy (at.%) parts were manufactured by hot isostatic pressing (HIP). The microstructure and high-temperature mechanical properties of the alloy were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that at a temperature of 700 °C, the peak yield stress (YS) and ultimate tensile stress (UTS) of alloy are 534 and 575 MPa, respectively, and the alloy shows satisfactory comprehensive mechanical properties at 850 °C. The alloy exhibits superplastic characteristics at 1000 °C with an initial strain rate of 5×10−5 s−1. When the tensile temperature is below 750 °C, the deformation mechanisms are dislocation movements and mechanical twinning. Increasing the tensile temperature above 800 °C, grain boundary sliding and grain rotation occur more frequently due to the accumulation of dislocations at grain boundary.Key words: TiAl alloy; near net shape; powder metallurgy; high-temperature mechanical properties1 IntroductionTiAl-based alloys are considered as promisingstructural materials for aerospace, automotive andenergy industries because of their low density, goodhigh-temperature strength, good creep resistanceand high resistance to oxidation [1−3]. Powdermetallurgy (PM), especially hot isostatic pressing(HIP) provides an alternative way to produce highquality TiAl alloys [4−6]. In recent years, HIP hasbeen applied to manufacturing the nearly fullydense parts with the refined and homogenousmicrostructure [7,8], even for metal parts with highprecision and complex shape [9−11].Many researchers have studied the influence ofthe HIP process parameters and densificationbehavior of TiAl alloy. HE et al [12] studied themicrostructural characteristics and densificationbehavior of high-Nb TiAl powder, and found thatmicrostructure and properties of HIPed billets wereinfluenced by the particle size of plasma rotatingelectrode processed powders. The microstructure ofthe HIPed billets produced by consolidating powderwith particle size at 105−200 μm showed someprimary particle boundaries and coarse lamellarstructure flaws, which had apparently inheritedeffects on the final consolidated billet after HIPprocess. HABLE and MCTIERNAN [13] studiedthe effects of HIP temperature (between 1200 andFoundation item: Project (51774335) supported by the National Natural Science Foundation of China; Project (2019JJ40374) supported by the Natural Science Foundation of Hunan Province, China; Project (CSUZC202004) supported by the Open SharingFund for the Large-scale Instruments and Equipments of Central South University, ChinaCorresponding author:Xiao-pengLIANG;Tel:+86-186********;E-mail:***************.cn;**************DOI:10.1016/S1003-6326(20)65438-3Hui-zhong LI, et al/Trans. Nonferrous Met. Soc. China 30(2020) 3006−3015 30071300 °C) on tensile properties of the Ti−46Al−2Cr−2Nb alloy, and found that the effect of HIP temperature on tensile properties is small when microstructural differences are largely eliminated. The tensile properties are more closely related to microstructure. YANG et al [14] studied the effects of heat treatment and particle size on the microstructures and tensile properties of the HIPed Ti4522XD alloy. They found that powder size and post-HIP aging had no significant influence on tensile properties, the HIPed microstructure of Ti4522XD alloy depended on the HIP temperature. There are some research reports on the mechanical properties of HIPed TiAl alloy at room temperature in Refs. [13,14], and limited investigations were conducted on the high-temperature properties of HIPed TiAl alloy. SHAGIEV et al [15] found that when the temperature was higher than 1000 °C, the HIPed Ti−47Al−3Cr alloy exhibited superplastic deformation characteristics.The relationship among high-temperature mechanical properties, microstructure and deformation mechanisms of powder metallurgy HIPed TiAl alloys are complex [16−18]. Our previous work [19−21] focused on the hot forging and rolling process of a PM Ti−45Al−7Nb−0.3W alloy, and found that the high-temperature (above eutectoid temperature) deformation mechanisms of TiAl alloy were grain boundary sliding, mechanical twins and dynamic recrystallization.In this work, a near net shaped Ti−45Al−7Nb−0.3W part was manufactured by HIP. The microstructure and high-temperature mechanical properties were investigated, and the deformation mechanism lower than eutectoid temperature was disscused.2 ExperimentalThe Ti−45Al−7Nb−0.3W (at.%) pre-alloyed powders with part icle size <100 μm were produced by plasma rotating electrode process (PREP), and the characteristics of the pre-alloyed powders have been reported in Refs. [12,19]. The near net shaped part was manufactured by HIP with powder and a mold core. The mold core model and the prepared part are shown in Fig. 1. The mold core model in Fig. 1(a) was prepared by high-purity graphite. The mold core and powder were placed in a stainless steel package and then vacuumed at 500 °C. Subsequently, the stainless steel can with powder and mold core were consolidated by HIP at 1250 °C and 150 MPa for 5 h, with a heating rate of 10 °C /min. After HIP treatment, the sample was cooled in furnace from 1250 to 100 °C in 6 h followed by air cooling. The HIPed TiAl alloy part has an oxygen content of 750×10−6 and a density of 99.8%. Figures 1(b) and (c) give the macrographs of the HIPed sample with and without package, respectively. By removing the extra parts and cleaning the surface of the sample, the HIPed near net shaped part is obtained (Fig. 1(d)).Fig. 1 Powder metallurgy Ti−45Al−7Nb−0.3W near net shape mold core model (a), HIPed specimen with steel package (b), photograph of specimen after removing package (c) and final near net shaped part (d)The high temperature mechanical properties were carried out on a RRC−50 testing machine at the temperatures ranging from 20 to 1000 °C and initial strain rates of 1×10−3, 1×10−4 and 5×10−5 s−1, respectively. The specimens were cut from the HIPed part and the gauge section has dimensions of 8 mm ×3.4 mm ×3 mm. Before testing, all specimens were held at the test temperature for 30 min.The phase constitution of the alloy analysis was carried out on a D/Max 2500 X-ray diffracto- meter (Cu Kαradiation, with voltage of 40 kV, current of 15 mA, diffraction angle (2θ) range of 10°−85°and step size of 0.02°). Quanta−200 scanning electron microscope (SEM) and Tecnai G220 Transmission electron microscope (TEM)Hui-zhong LI, et al/Trans. Nonferrous Met. Soc. China 30(2020) 3006−3015 3008were used for microstructure analysis. The TEM foils were thinned by twin-jet electropolishing using a solution consisting of 6% perchloric acid, 34% butanol and 60% methanol at −28 °C and 25 V.3 Results and discussion3.1 MicrostructureThe XRD pattern and SEM backscattered electron (BSE) image of the PM Ti−45Al−7Nb−0.3W alloy are presented in Fig. 2. The PM HIPed part is mainly composed of the γ phase and α2 phase (Fig. 2(a)). The SEM image in Fig. 2(b) reveals that the microstructure of alloy shows a near γmicrostructure, which is homogeneous and composed of equiaxed γ grains and a small amount of the α2/γ lamellar colonies. The mean grain size of the γphase is 9.3 μm. Meanwhile, the βphase whose fraction is too low to be detected by XRD is observed to distribute at the grain boundaries of γphase and α2/γ lamellar colonies with bright contrast in Fig. 2(b).Fig. 2XRD pattern (a) and SEM image (b) of HIPed Ti−45Al−7Nb−0.3W alloy 3.2 High-temperature mechanical propertiesThe influences of temperature on tensile properties of the PM Ti−45Al−7Nb−0.3W alloy with an initial strain rate of 1×10−4 s−1 are presented in Fig. 3(a). At room temperature, the ultimate tensile stress (UTS) and elongation of the alloy are 543 MPa and 0.2%, respectively. With increasing the temperature to 500 °C, the yield stress (YS) and ultimate tensile stress (UTS) decrease to 459 and 486 MPa, and the elongation is 1.4%. With further increasing temperature to 700 °C, the alloy exhibits peak YS (534 MPa) and UTS (575 MPa), which shows an anomalous strengthening. Then, the YS and UTS decrease again at elevated temperatures above 700 °C but the elongation always increases with temperature. When the TiAl alloy is tested at low temperatures (lower than 700 °C), the critical resolved shear stress (CRSS) to operate the 〈011] superdislocation is lower than that of ordinary dislocation [22], the 〈011] superdislocation can operate more easily. The dislocation motion isFig. 3Relationship between tensile properties and temperature of PM Ti−45Al−7Nb−0.3W alloy (a) and energy consumption per unit volume as function of temperature (b)Hui-zhong LI, et al/Trans. Nonferrous Met. Soc. China 30(2020) 3006−3015 3009closely related to the cross-slip of 1/2〈110] ordinary dislocations and 〈011] superdislocations [23,24]. The cross-slip of the superdislocation can induce some planar defects such as superlattice intrinsic stack fault (SISF) and complex stacking fault (CSF) [25,26]. With the temperature increasing, the cross-slip of ordinary dislocation can be activated. The planar defects can pin on those ordinary dislocations, and result in the formation of Kear −Wilsdorf dislocation locks [27,28], which is wildly regarded as the reason for anomalous strengthening. Meanwhile, the elongation of the alloy is 4.1% at 750 °C, and rapidly increases to 33% at 800 °C, which indicates that the brittle- ductile transition temperature of the alloy is between 750 and 800 °C. At 1000 °C, the YS and UTS drop to 116 and 133 MPa, while the elongation increases to 141%, which shows the superplastic deformation characteristic of the alloy.The comprehensive mechanical properties of alloy can be characterized by the energy consumption per unit volume when alloy fractures, which can be calculated by the area under engineering stress −strain curve, as Eq. (1).0=d v εσε⎰ (1)where v is the energy consumption per unit volume when alloy fractures, σ is the engineering stress andε is the engineering elongation during deformation.Figure 3(b) shows energy consumption per unitvolume when alloy fractures as a function ofthe test temperature, which increases from6.87×105 J/m 3 at 20 °C to 1.98×108 J/m 3 at 850 °C,and then decreases to 1×108 J/m 3 at 1000 °C. As aresult, the alloy shows satisfactory comprehensivemechanical properties at 850 °C with the YS, UTSand elongation of 351 MPa, 390 MPa and 67%,respectively.As already mentioned above, when thespecimen is tested at 1000 °C with an initial strainrate of 1×10−4 s −1, the elongation reaches 141%.This indicates that the alloy has superplasticdeformation characteristic, and it is furtherconfirmed by the tensile tests at 1000 °C with initialstrain rates of 1×10−3 and 5×10−5 s −1. The fracturedspecimens after deformation at 1000 °C withdifferent initial strain rates and their engineeringstress −strain curves are shown in Fig. 4. At 1000 °C,by decreasing the initial strain rate from 1×10−3 to5×10−5 s −1, the YS and UTS decrease from 195 and230 MPa to 80 and 96 MPa, respectively, while the elongation increases from 85% to 303%. The superplastic elongation corresponds to high strain rate sensitivity coefficient (m ), and the value of m is 0.3 in this study, which suggests that grain boundary sliding is the main deformation mechanism under this condition [29]. From the engineering stress −strain curves, it is found that the stress decreases obviously after it reaches the ultimate strength, indicating that the strain softening is dominant afterwards.Fig. 4 Engineering stress −strain curves at 1000 °C with different initial strain rates and images of fractured specimens after tensile deformation 3.3 Microstructures after high-temperature tensile deformation Figure 5 shows the fracture surfaces of the specimens tested at 20, 700, 850 and 1000 °C, respectively. It can be seen that the fracture modes are characterized by both the γ phase and the α2/γ lamellar colonies. The specimens are found to exhibit a brittle fracture mode at the temperatures of 20 and 700 °C. Numerous cleavage planes shown in Fig. 5(a) indicate that the predominant mode at 20 °C is transgranular fracture. Translamellar cleavage along α2/γ lamellar colonies was observed on the fracture surface of the specimen tested at 20 °C as shown in Fig. 5(a). At 700 °C, intergranular fracture along the γ grain boundaries is also observed in Fig. 5(b). This results from large deformation and imperfect lattice structure at grain boundaries, where microcracks are easy to be initiated and propagated due to the high stress concentration [19]. Many dimples can be clearly observed at 850 °C in Fig. 5(c), and the specimen exhibits a typical ductile fracture mode duringHui-zhong LI, et al/Trans. Nonferrous Met. Soc. China 30(2020) 3006−3015 3010tensile, while the α2/γlamellar colonies show an interlamellar cleavage mode at 850 °C. With the tensile temperature increases to 1000 °C, dimples are deep (Fig. 5(d)), and this is consistent with the high elongation in tensile properties.Figure 6 presents the SEM images of the deformed microstructures after tensile tests at 20, 700, 850 and 1000 °C, respectively. Compared with the microstructure of the HIPed specimen in Fig. 2(b), the microstructure after deformation at 20 and 700 °C shows no significant change and consists of equiaxed γgrains (Figs. 6(a) and (b)), and the α2/γlamellar structure shows no obvious orientation after being tested at 700 °C, as shown in Fig. 6(c). However, when the specimen is tested at 850 and 1000 °C, the γ grains are elongated along the load direction and a number of cavities are observed at grain boundaries (Figs. 6(d) and (e)).Fig. 5 Fracture surfaces of specimens tested at temperatures of 20 °C (a), 700 °C (b), 850 °C (c) and 1000 °C (d)Fig. 6 SEM images of specimens tested at temperatures of 20 °C (a), 700 °C (b, c), 850 °C (d) and 1000 °C (e, f)Hui-zhong LI, et al/Trans. Nonferrous Met. Soc. China 30(2020) 3006−3015 3011Especially after test at 1000 °C, α2/γlamellar colony is more aligned to the load direction (Fig. 6(f)).The high-temperature deformation behaviors of HIPed TiAl alloy are mainly dependent on microstructure evolution of the γgrain at test temperature. Meanwhile, the coordination role of a few α2/γlamellar colonies cannot be ignored. Previous literature reported that the α2/γlamellar colonies have different orientations which lead to different deformability. The yield stress is low when the load direction lies close to the lamellar plane (soft orientation) and is high when the load direction is nearly normal to the lamellar plane (hard orientation) [30,31]. In this research, the lamellar plane shows no specific orientation after being tested at the temperature below 700 °C (Fig. 6(c)), the α2/γlamellar colonies in hard orientation could improve the flow stress of HIPed TiAl alloy [32]. However, due to the inhomogeneous deformation between the γphase and α2/γ lamellar colonies, large plastic deformation occurs at the grain boundaries which lead to the formation of the cavities. Large number of cavities would result in fracture during deformation. When tested at a high temperature, α2/γ lamellar colonies are rotated and aligned to the load direction (Fig. 6(f)). The rotation of α2/γlamellar colonies can reduce the flow stress and is beneficial to the ductility of the alloy.The bright-field TEM images of the HIPed and deformed specimens tested at 20 °C and 700 °C are shown in Fig. 7. As shown in Fig. 7(a), the microstructure of the HIPed specimen mainly consists of equiaxed γgrains. A low density of dislocation can be observed in the γgrains. Meanwhile, many annealing twins are observed to exist in HIPed microstructure. During HIP process, high stress and temperature provide distortion energy for grain growth and migration of high angle grain boundary, which facilitate the formation of twins. In addition, the stacking fault energy of TiAl is low [23], thus annealing twins are substantially formed in the HIPed microstructure. When the alloy is tensile tested at 20 °C, the mechanical twinning is observed in the microstructures (Fig. 7(b)) and the dislocation density is obviously higher than the as-HIPed alloy after being tensile deformed at 20 and 700 °C (Figs. 7(c) and (d)). Meanwhile, the dislocations in γgrain are arranged in cross type and tangled, which can lead to the rapid increment of stored energy after high temperature test.Fig. 7 TEM images of HIPed specimen (a) and specimen tested at temperatures of 20 °C (b, c) and 700 °C (d)Hui-zhong LI, et al/Trans. Nonferrous Met. Soc. China 30(2020) 3006−3015 3012Figure 8 shows the TEM microstructure of the specimens deformed at 850 and 1000 °C. When the alloy tested at temperature above 850 °C, high density of dislocations tangled with each other in the γgrains (Fig. 8(a)). Meanwhile, dislocation networks are observed in γ grains (Fig. 8(b)). These dislocation networks formed related to entanglement of dislocations in γgrains while increasing the tensile temperature above 850 °C. COURET et al [33] reported that the dislocation networks can incorporate the dislocation, which is demonstrated by the presence of a number of extra half-threads in the rectangular network (Fig. 8(b)). The stable rectangular dislocation network consisting of cross-grid dislocations can impede the climbing and slipping of dislocation, and can result in severe work hardening [34,35]. With temperature increasing up to 1000 °C, high density of dislocations are observed accumulated at the grain boundaries due to dislocation climbing and slipping (Fig. 8(c)). These dislocations can cause large lattice distortion and improve the interface energy at grain boundary, which can improve the grain boundary migration. Therefore, grain boundary sliding (GBS) is the major mechanism for high-temperature deformation [36], which is activated by the interaction of dislocations, and deformation occurs along the most easily sliding surface. Due to the low stack fault energy of TiAl alloy [37−39], the mechanical twins are observed in TiAl alloys deformed at different temperatures (Fig. 7(b) and Fig. 8(d)). In the low stacking fault energy alloy, the mobility of dislocations reduces, so that twinning can be an alternative deformation mechanism to compensate the lack of glide systems [40,41]. Due to the fact that the twinning shear of mechanical twinning along 1/6 112]{111} is relatively small and atomic shuffling is not required during twinning, twins frequently appear in the γgrains and can contribute to relax stress concentration and accommodate deformation of the alloy [23].When the specimen is tested at 1000 °C and 5×10−5 s−1, the γ grains are more equiaxed (Fig. 9(a)) compared with those in the microstructure deformed at an initial strain rate of 1×10−4 s−1 (Fig. 6(e)). The density of dislocations decreases rapidly with decreasing the strain rate, and dislocations mainly appear at the grain boundaries (Fig. 9(b)). It can be seen from Fig. 4 that the ultimate tensile strength is closely related to the strain rate. With increasing the strain rate, the deformation resistance increases, and slipping of the dislocation is impeded. Therefore, dislocation accumulation occurs faster than recovery, resulting in a rapid increase in flow stress [42]. On the otherFig. 8 TEM images of specimens tested at temperature of 850 °C (a, b) and 1000 °C (c, d)Hui-zhong LI, et al/Trans. Nonferrous Met. Soc. China 30(2020) 3006−3015 3013Fig. 9 SEM (a) and TEM (b) images of specimen tested under conditions of 1000 °C and 5×10−5 s−1hand, when the strain rate is high, deformation of the HIPed alloy is still mainly related to climbing and slipping of dislocation and twinning (Figs. 8(c) and (d)). Thus, grains are elongated along the load direction, and a number of caves are found at grain boundaries (Fig. 6(e)). With decreasing the strain rate, the deformation process is longer, which is beneficial for dislocation movement, and offers enough time for the recovery process to reduce the dislocation density (Fig. 9(b)) and release the stress concentration. Grain boundary sliding is the main deformation mechanism during superplastic deformation, and the movability of grain boundaries depends on the orientation of the neighboring grains. In the early stage of deformation, only the grain boundaries in a favorable orientation can slip more easily during high temperature deformation, while climbing and slipping of dislocation are still dominating the remaining grains because the original grains show no specific orientation. During the deformation process, slipping and climbing of the grain boundary dislocations can improve the slip ability of the grain boundaries, thus the γ grains start to rotate, and become equiaxed. Rotation of γgrains cannot contribute to deformability directly. However, as more γgrains rotate to the favorable orientation, grain boundary sliding and coordination mechanism of γgrains would be more easily activated. As a consequence, the flow stress is reduced and the elongation increases rapidly at low strain rates.4 Conclusions(1) The ultimate tensile strength of HIPed Ti−45Al−7Nb−0.3W part increases from 543 MPa at room temperature to 575 MPa at tensile temperature of 700 °C, and the elongation increases from 0.2% to 2.9%. The alloy shows satisfactory comprehensive mechanical properties at 850 °C with the YS, UTS and elongation of 351 MPa, 390 MPa and 67%, respectively.(2) When the deformation temperature is lower than 700 °C, the deformation mechanism mainly refers to dislocation movements and mechanical twining in the near γmicrostructure HIPed TiAl alloy. When the deformation temperature is higher than 850 °C, the deformation mechanism is related to the combination of dislocation movements, mechanical twinning, grain boundary sliding and the rotation of α2/γ lamellar colonies.(3) The near γmicrostructure HIPed alloy displays superplastic characteristic at 1000 °C and strain rate of 5×10−5 s−1. In this case, dynamic recovery reduces the dislocation density and the grain boundary sliding is promoted by γgrain rotation, which results in a rapid decrease in flow stress and improves elongation.References[1]ISMAEEL A, WANG Cun-shan. Effect of Nb additions onmicrostructure and properties of γ-TiAl based alloys fabricated by selective laser melting [J]. Transactions of Nonferrous Metals Society of China, 2019, 29: 1007−1016.[2]LIANG Xiao-peng, LIU Yong, LI Hui-zhong, ZHOU Can-xu,XU Guo-fu. Constitutive relationship for high temperature deformation of powder metallurgy Ti−47Al−2Cr−2Nb−0.2W alloy [J]. 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