Prospects for detection of very high energy emission from GRB in the context of the Externa
高一英语科学发现词汇应用高级单选题40题
高一英语科学发现词汇应用高级单选题40题1. In the process of scientific research, a(n) ____ is often put forward first, which is a proposed explanation for a phenomenon.A. experimentB. hypothesisC. observationD. conclusion答案：B。
解析：本题考查科学发现相关词汇的辨析。
“hypothesis”意为假设，在科学研究中通常首先提出一个假设来解释某种现象，这是科学研究的常见步骤。
“experiment”是实验，是用来验证假设的手段，而非首先提出的内容。
“observation”是观察，虽然观察也是研究的一部分，但不是这种对现象提出解释的概念。
“conclusion”是结论，是在经过一系列研究之后得出的结果，不是一开始就提出的。
2. Scientists made a careful ____ of the strange phenomenon before they started their research.A. experimentB. hypothesisC. observationD. discovery答案：C。
解析：这里考查词汇的语境运用。
“observation”表示观察，科学家在开始研究之前会对奇怪的现象进行仔细观察，这是符合逻辑的。
“experiment”是进行实验，在还未开始研究时不会先进行实验。
“hypothesis”是假设，此时还未到提出假设的阶段。
“discovery”是发现，这里强调的是对现象的观察过程，而不是发现这个结果。
3. The ____ they designed was very complicated but it could test their hypothesis effectively.A. experimentB. observationC. conclusionD. theory答案：A。
大学生不诚信行为英语作文范文
大学生不诚信行为英语作文范文全文共3篇示例，供读者参考篇1The Slippery Slope of Academic DishonestyAs a college student, I've witnessed far too many instances of cheating, plagiarism, and other forms of academic dishonesty. It's a problem that seems to be getting worse, not better, despite universities' efforts to crack down on such behavior. From students brazenly exchanging answers during exams to purchasing pre-written papers online, the temptation to gain an unfair advantage is ever-present. And the consequences are serious – those who engage in academic dishonesty tarnish the integrity of their degrees and put their future prospects at risk. It's a destructive habit that simply isn't worth the gamble.In my opinion, academic dishonesty stems from a combination of factors. The immense pressures we face as students play a major role. With rising tuition costs, the need to maintain high GPAs for scholarships, and the cut-throat competition for jobs and graduate programs, some students feel pushed to the breaking point. Cheating can start to look like theonly way to keep their heads above water. I've had classmates confess that they were overwhelmed by deadlines and sleep deprivation, which impaired their judgment. While that's no excuse, I can empathize with being stretched too thin.The rampant culture of academic dishonesty is also aself-perpetuating cycle on many campuses. When students constantly see their peers cheating without facing consequences, it can make dishonest behavior seem normal and low-risk. The perceived prevalence of cheating lowers ethical barriers. As one friend rationalized to me, "Everyone else is doing it, so why shouldn't I level the playing field?" This flawed logic is surprisingly common.Let's face it – technology has made academic dishonesty much easier than it once was. Forgetting to cite a source properly and inadvertently plagiarizing has become all too easy in the copy-and-paste era. And the internet has also birthed a lucrative industry of paper mills and other cheating services, just a click away for those struggling with assignments. The accessibility and anonymity enable bad choices.That said, I don't believe technology is solely to blame. These rationalizations sidestep the core issue of personal integrity. When I consider students who are patent about earning theirachievements through hard work and perseverance, it reinforces my belief in doing the right thing. Resorting to academic dishonesty is a short-sighted move that could derail one's entire future.I've seen bright students get expelled after getting caught plagiarizing or cheating, nullifying years of hard work and investment. The punishments are harsh because they should be –academic dishonesty is ultimately a form of fraud. How can future employers trust someone who took unethical shortcuts in school? Degrees and transcripts are supposed to be honest representations of knowledge and capabilities earned. I worked hard for my grades, so it's disheartening to know others have devalued them through cheating.Of course, the line between collaborative learning and unauthorized assistance isn't always clear. I believe study groups and peer editing are acceptable, even crucial, parts of the educational experience. The problems arise when students go beyond discussing concepts to directly sharing answers or having others complete their work. It's a fine line, but an important one that requires integrity.Ultimately, academic dishonesty is a personal choice. While professors and schools should enforce strict policies todisincentivize cheating, they can't monitor every student's conscience. It's up to each of us to search our souls and commit to academic honesty for its own sake. A hard-earned "C" is far more honorable than an ill-gotten "A".Some struggle with prioritizing honesty when they feel backed into a corner. But looking at the long-term repercussions, that way lies a dangerous path of compromising one's principles again and again, rationalization after rationalization. Before you know it, you've strayed miles from your ethical foundations. Cheating in college can breed habits of cutting corners professionally down the line. Why risk staining your reputation over a few assignments?I'm certainly not perfect – I've been tempted by cheating's lure like anyone else when overwhelmed by deadlines. But I've found motivating myself to study smarter rather than look for shortcuts. I've learned to manage my schedule more efficiently and not leave everything until the last minute. When I've lapsed, I've been upfront about mistakes, taken my lumps, and tried to grow from them.At the end of the day, our college years help mold the adults we'll become. Developing strong ethics around academic honesty sets an important foundation for being people ofintegrity. While the path of least resistance can be appealing in the moment, true fulfillment comes from knowing you earned your achievements through your own merit. When I walk across that stage at graduation, I'll be proud that the degrees I earned represent years of perseverance, original work, and ethical choices – not just a hollow credential attained through fraud.So I'd encourage any students wrestling with academic dishonesty to pause and consider the long-term implications. Think back to what motivated you to pursue higher education in the first place. Was it to cut corners and take the easy way out, or to challenge yourself into becoming a better-rounded thinker and ethical person? The purpose of a college education goes far beyond checking boxes. It's about intellectual growth and building the personal values to navigate life with honor. All the cheating in the world won't make you a good person at your core.篇2The Scourge of Academic Dishonesty on University CampusesAs a university student, I have witnessed firsthand the concerning prevalence of academic dishonesty among my peers.From plagiarism and cheating on exams to unauthorized collaboration and fabrication of data, these unethical behaviors not only undermine the integrity of our academic institutions but also devalue the hard work and achievements of honest students.Plagiarism, the act of presenting someone else's work as one's own, is perhaps the most common form of academic dishonesty. With the abundance of information readily available on the internet, it has become increasingly tempting for students to copy and paste content from online sources without proper attribution. However, this practice is not only a violation of academic integrity but also amounts to intellectual theft. It robs the original authors of their due credit and deprives students of the opportunity to genuinely learn and develop their skills.Cheating on exams is another major concern that plagues university campuses. From smuggling in cheat sheets or unauthorized materials to employing technological aids like smartphones or smartwatches, students resort to various underhanded tactics to gain an unfair advantage. This behavior not only undermines the purpose of assessments, which is to evaluate students' knowledge and understanding, but alsocreates an uneven playing field for those who diligently prepare and study.Unauthorized collaboration, while sometimes stemming from genuine misunderstandings about assignment guidelines, can also be a deliberate attempt to circumvent academic rules. When students work together on assignments meant to be individual efforts or share solutions without permission, they are engaging in a form of cheating that undermines the integrity of the assessment process.Fabrication of data, although less common, is perhaps one of the most egregious forms of academic dishonesty. When students manipulate or wholly manufacture research data to fit their desired outcomes, they not only compromise the validity of their work but also undermine the credibility of academic research as a whole.The consequences of academic dishonesty are far-reaching and severe. Beyond the potential for disciplinary action, such as failing grades or even expulsion, engaging in these unethical practices can have long-lasting effects on a student's moral character and professional reputation. Employers and graduate programs often place a high value on academic integrity, and arecord of dishonest behavior can seriously hinder future prospects.Moreover, academic dishonesty undermines the very purpose of higher education, which is to cultivate critical thinking, intellectual curiosity, and a thirst for knowledge. When students resort to cheating or plagiarism, they deprive themselves of the opportunity to truly engage with the material, develop their skills, and grow as scholars and individuals.It is essential for universities to take a strong stance against academic dishonesty and implement robust policies and procedures to deter and address such behaviors. This includes clear communication of academic integrity standards, rigorous plagiarism detection systems, and fair but firm consequences for violations. Additionally, promoting a culture of academic honesty through education and awareness campaigns can help instill a sense of ethical responsibility in students from the outset of their academic careers.However, the responsibility for upholding academic integrity does not fall solely on institutions; students must also take an active role in this endeavor. We must cultivate a peer culture that values honesty, hard work, and intellectual curiosity over shortcuts and easy gains. Encouraging open discussions aboutthe pressures and challenges that may lead to academic dishonesty can help foster a more supportive and understanding environment, where students feel empowered to seek legitimate assistance when needed.Ultimately, academic dishonesty is a complex issue with no simple solutions. It requires a multifaceted approach involving institutional policies, educational initiatives, and a collective commitment from students to uphold the values of academic integrity. As students, we must recognize that our actions not only impact our individual journeys but also shape the reputation and credibility of our institutions and the broader academic community.By embracing honesty, ethical conduct, and a genuine passion for learning, we can create a culture of academic excellence that truly embodies the spirit of higher education. It is a challenge we must collectively embrace, for the sake of our personal growth, the integrity of our institutions, and the advancement of knowledge itself.篇3Dishonesty in Academia: A Troubling TrendAs a college student, I have witnessed firsthand the alarming prevalence of unethical behavior within academic settings. From blatant cheating on exams to plagiarizing entire papers, the lack of integrity among some of my peers is deeply concerning. In this essay, I will delve into the various forms of academic dishonesty, explore the potential causes behind this disturbing trend, and discuss the far-reaching consequences it poses for individuals and society as a whole.Cheating on exams is perhaps the most blatant and widely recognized form of academic misconduct. Whether it's surreptitiously glancing at a classmate's paper, smuggling in unauthorized notes, or utilizing sophisticated technological aids, the act of cheating violates the fundamental principles of fairness and academic integrity. What's more concerning is the normalization of this behavior among certain student groups, where cheating is perceived as a means to an end, justifying the unethical actions as necessary for academic success.Plagiarism, the act of presenting someone else's work as one's own, is another pervasive issue within academic circles. With the wealth of information readily available online, some students succumb to the temptation of copying and pasting content without proper attribution. This not only undermines thevalue of original thought and hard work but also constitutes intellectual theft, robbing authors of the credit they deserve for their contributions.Beyond cheating and plagiarism, other forms of academic dishonesty include fabricating data, falsifying research findings, and engaging in unauthorized collaboration on individual assignments. These practices erode the very foundation of higher education, which aims to foster critical thinking, independent inquiry, and the pursuit of knowledge.While the motivations behind such unethical behavior may vary, several potential factors contribute to this troubling trend. Firstly, the immense pressure to achieve academic excellence, fueled by intense competition for coveted scholarships, internships, and future career prospects, can drive some students to resort to desperate measures. The fear of failure and the desire for success can cloud their moral judgment, leading them down a path of academic dishonesty.Additionally, the widespread availability of technology and online resources has made cheating and plagiarism more accessible than ever before. With a few clicks, students can access vast repositories of pre-written essays, test banks, and other materials that facilitate academic misconduct. Theperceived anonymity and ease of access to these resources can further embolden students to engage in unethical practices.Furthermore, the lack of clear consequences or strict enforcement of academic integrity policies within some institutions may inadvertently perpetuate this behavior. If students witness their peers engaging in dishonest practices without facing substantial repercussions, it can foster a sense of complacency and a belief that such actions are acceptable or even necessary for academic survival.The consequences of academic dishonesty extend far beyond the classroom walls. On an individual level, students who engage in unethical practices deprive themselves of the opportunity to develop critical thinking skills, intellectual curiosity, and a genuine appreciation for learning. They may gain short-term advantages, but in the long run, they undermine their own personal and professional growth, as well as their ability to contribute meaningfully to their chosen fields.Moreover, academic dishonesty erodes the credibility and reputation of educational institutions. Universities and colleges pride themselves on producing knowledgeable, ethical, and well-rounded graduates who will shape the future of various industries and societies. When academic integrity iscompromised, it casts doubt on the quality of education and the value of the degrees conferred, potentially tarnishing the institution's standing and diminishing the worth of the qualifications held by all its graduates.On a broader societal level, academic dishonesty perpetuates a culture of deceit and undermines the fundamental values of honesty, integrity, and ethical conduct. As these students transition into the professional world, carrying with them the habits and attitudes cultivated during their academic careers, they may perpetuate unethical practices in their respective fields, adversely impacting industries, organizations, and communities.Furthermore, academic dishonesty can have far-reaching implications for fields that rely heavily on research and innovation, such as medicine, technology, and scientific exploration. If research findings are fabricated or plagiarized, it can lead to flawed conclusions, faulty decision-making, and potentially dangerous consequences for public health, safety, and progress.Combating academic dishonesty requires a multifaceted approach involving educational institutions, faculty members, students, and society as a whole. Universities and colleges mustimplement and strictly enforce robust academic integrity policies, clearly outlining the consequences of unethical behavior and fostering an environment that values honesty and ethical conduct.Faculty members play a crucial role in setting the tone and modeling ethical behavior for their students. They should not only emphasize the importance of academic integrity but also design assessments and assignments in a manner that discourages cheating and plagiarism. Additionally, they can leverage technology to detect instances of academic misconduct and address them swiftly and fairly.Students, too, bear a significant responsibility in upholding academic integrity. We must cultivate a culture of honesty and mutual accountability, where unethical behavior is not tolerated or enabled. By recognizing the long-term benefits of ethical conduct and the value of genuine learning, we can collectively reaffirm the principles that underpin the pursuit of knowledge.Lastly, societal forces, including parents, role models, and the media, should promote the importance of academic integrity and emphasize the consequences of dishonest behavior. By fostering a culture that celebrates hard work, perseverance, andethical conduct, we can inspire future generations of students to embrace academic honesty as a core value.In conclusion, the prevalence of unethical behavior among college students is a troubling trend that demands immediate attention and decisive action. Academic dishonesty not only undermines the value of education but also has far-reaching consequences for individuals, institutions, and society as a whole. By fostering a culture of integrity, implementing robust policies, and promoting ethical conduct, we can preserve the sanctity of academia and ensure that our institutions remain bastions of knowledge, critical thinking, and intellectual growth.。
Lung cancer
Lung cancer: a global scourgeLancet.2013 Aug 24Worldwide, lung cancer killed about 1·5 million people in 2010. Lung cancer has an extremely poor prognosis, with an overall 5 year survival of 16% in the USA and less than 10% in the UK. To achieve a substantial reduction in lung cancer mortality, global action and progress in prevention, early detection, and treatment are crucial.Today's Lancet features a Clinical Series on lung cancer ahead of the 2013 European Respiratory Society congress in Barcelona, Spain, on Sept 7—11. The three reviews discuss in depth recent developments in the management of patients with non-small-cell lung cancer, prospects for personalised treatment for lung cancer, and lung cancer screening, respectively. The debate on screening for lung cancer has recently been fuelled by the release on July 30 of the US Preventive Services Task Force's draft recommendations. The Task Force recommends CT screening of individuals aged 55—79 years with at least a 30 pack-year history of smoking and who have smoked within the past 15 years. As John Field rightly stresses in the third paper of the Series, “the health-care system in the USA is very different to that in Europe”. In this context, the results of European trials of CT screening—such as the Dutch trial NELSON, which notably includes routine care and not chest radiography for the control group—are much awaited. Questions around cost-effectiveness, assessment of nodules to reduce false positives, and selection of high-risk groups remain divisive, and will surely be discussed at the European Respiratory Society congress. Given the poor prognosis of advanced lung cancer, identification of patients at the earliest stage of the disease is crucial; whether this is by targeted screening, once the appropriate evidence is available, or by early detection and rapid referral of people most at risk, is a matter of strategy and health-system capability.。
作弊现象英语作文
作弊现象英语作文Cheating is a serious issue that plagues educational institutions around the world. It undermines the integrity of the learning process and can have long-lasting effects on the students involved, as well as on the educational system as a whole.The Prevalence of CheatingIn recent years, the prevalence of cheating has increased significantly, especially with the advent of technology. Students can easily access information, share answers, and even use sophisticated tools to cheat on exams. This has led to a decrease in academic honesty and an increase in the need for stricter measures to prevent cheating.Reasons Behind CheatingThere are various reasons why students cheat. Some of the common motivations include the pressure to achieve high grades, fear of failure, lack of understanding of the material, and the desire to save time. Additionally, some students may cheat due to a lack of moral compass or because they believe that the rewards of cheating outweigh the risks.Consequences of CheatingThe consequences of cheating can be severe. For students, itcan lead to academic penalties such as failing the course, suspension, or even expulsion. Moreover, it can damage their reputation and future prospects. For the educational system, cheating erodes trust and undermines the value of the degrees and qualifications it awards.Strategies to Combat CheatingTo combat cheating, educational institutions have implemented various strategies. These include the use of plagiarism detection software, proctoring services for online exams, and the promotion of academic integrity. Teachers are also encouraged to design exams that are less susceptible to cheating, such as open-book tests or projects that require original thought and creativity.The Role of Students and EducatorsBoth students and educators have a role to play in addressing the issue of cheating. Students should be encouraged to value the learning process and understand the importance of academic honesty. Educators, on the other hand, should strive to create an environment that fosters integrity and discourages dishonest behavior.ConclusionCheating is a complex problem that requires a multifaceted approach to solve. It is essential for students to understand the value of education and the consequences of cheating. At the same time, educators must continue to adapt and implementstrategies to prevent cheating and promote a culture of academic integrity. Only through a combined effort can we hope to reduce the prevalence of cheating and uphold the sanctity of education.。
圆环阵太阳射电成像望远镜读后感
英文回答：The Circular Ring Array Solar Radio Telescope (CRAST) represents a groundbreaking advancement in the field of solar radio imaging, offering unparalleled capabilities for high-resolution observation of solar phenomena. Its distinctive design,prising a circular array of multiple antennas, facilitates the detailed visualization of solar flares, coronal mass ejections, and solar wind. The unique circular arrangement of the antennas affords an expansive field of view, enabling theprehensive monitoring of dynamic solar events occurring across a vast area of the solar disk. This capacity is of utmost importance for gaining insight into theplex processes occurring within the solar atmosphere and for enhancing our ability to predict space weather phenomena that can have consequential impacts on terrestrial technologies.环形阵列太阳射电望远镜（CRAST）是太阳射电成像领域的一个突破性进展，为太阳现象的高分辨率观测提供了前所未有的能力。
康复辅助机器人及其物理人机交互方法
第44卷第11期自动化学报Vol.44,No.11 2018年11月ACTA AUTOMATICA SINICA November,2018康复辅助机器人及其物理人机交互方法彭亮1侯增广1,2,3王晨1,2罗林聪1,2王卫群1摘要面对中国社会快速老龄化现状和庞大的残疾人群,康复辅助机器人研究具有重要学术价值和广阔的应用前景.康复辅助机器人研究涉及神经科学、生物力学、机器人自动控制等领域知识,是机器人最具挑战性和最受关注的研究领域之一.与其他机器人不同,康复辅助机器人的作用对象是人,存在人与机器人的信息交流和能量交换,物理人机交互控制方法是其研究核心和关键技术.本文以神经康复机器人、穿戴式外骨骼、智能假肢等应用为例,介绍当前的研究现状,并重点介绍人体运动意图识别方法和交互控制方法等研究重点和难点.最后展望该领域的未来技术发展方向.关键词康复机器人,辅助机器人,物理人机交互,意图识别,交互控制引用格式彭亮,侯增广,王晨,罗林聪,王卫群.康复辅助机器人及其物理人机交互方法.自动化学报,2018,44(11):2000−2010DOI10.16383/j.aas.2018.c180209Physical Interaction Methods for Rehabilitation and Assistive Robots PENG Liang1HOU Zeng-Guang1,2,3WANG Chen1,2LUO Lin-Cong1,2WANG Wei-Qun1Abstract With the rapid growth of China s aging and disabled population,researches on rehabilitation and assistive robots have great value to technical study and good prospects for applications.Rehabilitation and assistive robots involve the domain knowledge of neuroscience,biomechanics,robot automatic control,etc.,thus are one of the most challenging and most concerned research areas of robotics.As the application contexts of rehabilitation and assistance entail information communication and energy exchange between man and robot,the physical human-robot interaction control method is the key theme.This article briefly introduces the states of the art of neurorehabilitation robots, wearable exoskeletons,and intelligent prostheses,and focuses on the key issues and research priorities in human motion intent detection methods and interaction control methods.Finally,the future development directions are prospected. Key words Rehabilitation robot,assistive robot,physical human-robot interaction,intention detection,interaction controlCitation Peng Liang,Hou Zeng-Guang,Wang Chen,Luo Lin-Cong,Wang Wei-Qun.Physical interaction methods for rehabilitation and assistive robots.Acta Automatica Sinica,2018,44(11):2000−2010随着自动化和人工智能技术的发展,智能机器人应用不再局限于传统的工业和制造业,而被广泛应用到医疗健康、教育服务、军事和空间探索等领域.其中,随着计算机、传感器、神经工程、信息处收稿日期2018-04-11录用日期2018-08-01Manuscript received April11,2018;accepted August1,2018国家自然科学基金(61720106012,U1613228,61603386,615330 16),北京市自然科学基金(L172050,Z170003),中国科学院战略性先导科技专项(XDBS01040100)资助Supported by National Natural Science Foundation of China (61720106012,U1613228,61603386,61533016),Beijing Natural Science Foundation(L172050,Z170003),and Chinese Academy of Sciences Strategic Pilot Project(XDBS01040100)本文责任编委孙健Recommended by Associate Editor SUN Jian1.中国科学院自动化研究所复杂系统管理与控制国家重点实验室北京1001902.中国科学院大学北京1000493.中国科学院脑科学与智能技术卓越创新中心北京1001901.State Key Laboratory of Management and Control for Complex Systems,Institute of Automation,Chinese Academy of Sciences(CAS),Beijing1001902.University of Chinese Academy of Sciences,Beijing1000493.CAS Center for Ex-cellence in Brain Science and Intelligence Technology,Beijing 100190理等技术的飞速发展,康复与辅助机器人的广泛研究也已经有近30年的历史.康复与辅助机器人的发展不仅为神经科学和康复医学带来了极大的技术进步和观念变革,而且作为一种高新技术产业已经成为世界经济新的增长点,相关研究得到世界各国的重视,成为技术竞争的重要领域之一[1].同时,随着全球特别是中国社会老龄化的加剧,对康复辅助机器人的需求也在不断增加,为该领域的发展提供了更广阔的市场空间和难得的发展机遇.中国人口老龄化形势严峻,已经成为世界上老年人最多的国家.截止到2014年底,我国60岁以上老龄人口已达2.12亿,并且将在2025年达到3亿.同时,由脑卒中、脊髓损伤、脑外伤等原因造成的残障人口数量迅速增长,我国肢体残疾人口逾2400万,每年新增脑卒中患者约200万,大多数患者都具有一定程度的功能障碍.传统的康复训练基于人工手段,而我国专业治疗师非常紧缺,美国康复治疗师数量为70人/10万人,而我国目前仅为0.411期彭亮等:康复辅助机器人及其物理人机交互方法2001人/10万人,且专业水平低,无法满足日益增长的需求.康复辅助机器人的使用能够提高康复效率,降低治疗成本,减少人员需求和体力消耗,同时可以提高康复效果,其研究进展为神经损伤患者、残疾人、老年人的功能康复和生活辅助带来了希望.康复辅助机器人涉及神经科学、生物力学、人因工程、机器人自动控制等领域知识,是典型的多学科交叉的复杂系统,其研究具有较高的挑战性.其中机器人自动控制起着非常关键的作用,在充分理解临床实际需求的基础上,需要利用控制理论的建模、分析与综合工具,并结合其他学科理论和技术,最终实现临床目标.与其他机器人相比,康复辅助机器人有其不同特点和控制要求.康复辅助机器人的作业对象是人,其性能必须满足对个体差异和环境变化的适应性,人机交互的柔顺性,面对异常情况的安全性,以及对人体生理心理的适应性等要求,从而对控制系统的准确性、可靠性、智能化水平等都提出更高的要求.在康复辅助机器人应用中,由人和机器人两个具有一定自主性的个体共同完成目标,两者之间的双向信息交流非常重要.另一方面,对于康复辅助机器人,人和机器人耦合在一起,存在物理人机交互(Physical human-robot interaction,pHRI),两者之间的角色分配和能量交互控制非常关键[2].首先,机器人需要了解人的意图,配合其完成期望的运动,即意图识别过程;然后,人和机器人在交互中的角色和作用在动态改变,人机之间的能量交互过程随之进行动态调整,以满足康复或辅助的目标,即交互控制策略[3].除此之外,机器人需要将其当前的状态及时反馈给人,同时保证人在交互过程中的安全[4].本文以神经康复机器人、穿戴式外骨骼、智能假肢等应用为例,介绍当前的研究现状,并重点探讨人体运动意图检测方法和交互控制方法等研究重点和难点.最后展望该领域的未来技术发展方向.1康复辅助机器人的发展现状康复辅助机器人的广泛研究开始于20世纪90年代,最早是以工业机器人作为研究平台,随着研究的深入,逐渐成为独立的机器人大类,包括神经康复机器人、穿戴式外骨骼、智能假肢、智能轮椅等.以神经康复机器人为例,按照不同的训练部位划分,有上肢、下肢、手指、手腕、踝关节等不同种类,根据文献[5]统计,目前处于研究阶段的各类上肢康复机器人已经超过100种.1.1神经康复机器人按照机器人的结构特点,神经康复机器人可以分为末端牵引式和外骨骼式两大类,前者主要采用多连杆机构,通过末端执行器与患者肢体末端接触;后者仿照人体结构进行设计,实现与患者各关节运动的对应.早期上肢康复机器人以美国麻省理工学院的MIT-Manus[6]机器人为代表,属于末端牵引式,主体结构采用平面五连杆,共两个自由度,主要用于中风患者肩、肘关节的康复运动训练(图1(a)).该机器人采用阻抗控制方法,根据不同患者设计不同的力场,患者借助机器人的辅助学习运动技巧,实现功能康复[7].由苏黎世联邦理工大学研发的ARMin[8]上肢康复机器人,是外骨骼式上肢康复机器人的典型代表,共5个自由度(肩部3个、肘部1个、前臂1个),能够实现肩关节内收/外展、旋内/旋外、前屈/后伸,肘关节屈/伸,前臂旋前/旋后等动作,手部设计了用以辅助抓握训练的模块,并配有力传感器,提供主动训练模式.该机器人还集成了虚拟现实训练环境,可以模拟做饭、打扫等日常动作.多中心随机对照临床试验结果证明,ARMin对于患者的康复能够取得较好效果[9].瑞士Hocoma公司已经将ARMin机器人成功商业化,并在其基础上开发出Armeo Power系列康复机器人(图1(b)).图1MIT-Manus与Armeo Power上肢康复机器人Fig.1MIT-Manus and Armeo Power upper limbrehabilitation robots下肢康复机器人所需扭矩较大,同时需要考虑支撑人体部分甚至全部重量,以悬吊减重式为主要形式.国际上最具影响力的是由瑞士苏黎世大学医学院、苏黎世联邦理工学院、苏黎世大学、Hocoma 公司和德国Woodway公司联合研发,由Hocoma 公司商业化的Lokomat[10]下肢康复机器人(图2).它主要由一对腿部外骨骼、跑步机和悬吊减重系统构成,其中每条腿部外骨骼有两个自由度,控制髋膝关节在矢状面屈伸运动,同时与跑步机和虚拟现实训练界面同步配合,实现下肢的模拟步态训练.为满足不同患者的康复需求,Lokomat实现了多种主被动训练策略[11],根据患者在训练过程中的实际表现对辅助力进行调整.2002自动化学报44卷图2瑞士Hocoma 公司的Lokomat 下肢康复机器Fig.2Lokomat lower limb rehabilitation robot1.2穿戴式外骨骼机器人穿戴式外骨骼机器人是近些年发展起来的一种新型机器人,具有极大的灵活性和空间拓展性,其穿戴于患者身上,对人体运动能力具有一定的的延伸、补偿甚至超越的功能[12].具有代表性的是美国加州大学伯克利分校研发的BLEEX [13]助力型下肢外骨骼机器人,由液压驱动,采用仿生设计,每条腿有7个自由度,包含30多个传感器,可在负重75kg 下以0.9m/s 速度行走,主要应用于士兵野外作战.继BLEEX 研制成功后,其技术由军用转向民用,研发出了Ekso [14]系列下肢外骨骼,主要用于帮助下肢失去行动能力的截瘫患者或下肢肌无力患者重新站立起来.日本筑波大学研发的HAL [15]系列外骨骼机器人(图3(a)),定位于康复医疗、残疾人助力以及救灾等场合,采用电机驱动,并创新使用肌电信号获取人的运动意图.由以色列科学家研制成功的Rewalk [16]外骨骼机器人(图3(b))包含两类产品,分别是个人版和康复版.个人版能够让截瘫患者重新站立起来,因此强调针对单一病人量身设计,适合于在家庭和社区使用,康复版面向康复中心设计,能够提供步态康复训练.上述外骨骼机器人普遍采用刚性结构和电机驱动,存在体积大、重量高、刚性强、穿戴不便等缺点,从而催生了柔性驱动的软体外骨骼机器人的出现.软体外骨骼通常采用气动驱动方式,重量轻,而气动驱动器本身可压缩,具有较高的柔顺性.哈佛大学Walsh 团队[17],将气动人工肌肉固定在特制的外套上,对髋、膝、踝关节进行运动辅助,整个设备包含气源只有7.1kg,相比于电机驱动的刚性外骨骼要轻得多,并能够在驱动情况下显著减小人的平均代谢图3外骨骼机器人Fig.3Exoskeletal robots11期彭亮等:康复辅助机器人及其物理人机交互方法2003能量.在此研究基础上,该团队研制了一款新型的软性外骨骼Soft Exosuit [18],通过绳传动方式,将位于腰部的电机驱动沿着特殊编织而成的软性外衣传递到足跟,实现对用户的辅助(图4).其创新之处还在于设计了一种基于碳纤维织物的具有弹性的力传感器[19].与传统的刚性外骨骼相比,该设计的优势在于用户的关节活动不会受到外部刚性结构的限制,且整个设备质量很轻,从而减少外骨骼对用户的干涉,有助于实现更加自由灵活的交互.图4美国哈佛大学研制的Soft Exosuits 外骨骼机器人Fig.4Soft Exosuits from Harvard University1.3智能假肢对于截肢患者,主要通过安装假肢完成其丧失的功能,实现生活自理.传统的机械式假肢舒适性差、自由度少、使用不便,影响患者的使用体验,且实现的功能有限.与之相比,动力型假肢具有较高的集成度,以及与人体类似的自由度和灵活性,但多自由度假肢的控制具有非常高的挑战性.目前,由肌电信号驱动的智能假肢控制方案是最有前景的解决方案,肌电信号与肢体的运动具有较高的相关性,早在1948年,德国的Reiter [20]研制成功了世界上第一只肌电控制的假手,利用残余肢体的肌电信号信息控制假手的开合.随着患者截肢程度越高,所需要代偿的自由度越多,其控制所需的信息越多,而残肢可供利用的控制信号也越少,因此传统的肌电假肢控制方法很难实现多自由度假肢的意念控制.目前,结合肌肉神经功能重建手术和模式识别方法,有望解决多自由度假肢控制难题.靶向肌肉神经功能重建(Targeted muscle reinnervation,TMR)手术将残存神经转接到特定靶向肌肉中,从而重建因截肢失去的运动神经信息源.美国芝加哥康复研究中心Kuiken 等[21]采用TMR 手术,将上肢截肢者的残余臂丛神经植入同侧胸大肌,然后利用阵列电极实现对肌电信号的采集,最后通过特征提取、模式识别方法,实现对患者期望动作的识别,并控制假肢完成动作,首次实现了经肱骨截肢者以直觉控制多功能肌电假肢.中国科学院深圳先进技术研究院李光林团队[22]对TMR 进行优化和改良,提出一种新的神经功能重建方法—目标神经功能替代术(Targeted nerve functional replacement,TNFR),并采用TMR 方法与TNFR 方法相结合的方式,首次在国内对经肱骨截肢者成功实施了神经功能重建术,建立了经肱骨截肢者神经功能重建模型,利用高密度电极采集因截肢而丧失的肌电信息,并通过LDA (Linear discriminant analysis)分类器对7类手部动作进行识别,分类精度达到95%以上,实现意念控制多功能肌电假肢的目的.2006年,德国Otto Bock 公司研发了世界上首款仿生智能假肢C-Leg [23](图6(a)),集成了控制器、电源模块、传感器、无线收发装置等,根据力矩传感器信息判断步态的支撑期与摆动期,通过控制器调节液压缸关节阻尼,保证稳定的行走,并实现能图5基于TMR 手术和表面肌电信号控制的动力型假肢Fig.5Power prothesis controlled by sEMG signal via targeted muscle reinnervation2004自动化学报44卷图6仿生假肢与动力假肢Fig.6Bionic prostheis and powered prosthesis量的储存与释放.2014年,美国范德堡大学[24]研制了一款电动膝上假肢(图6(b)),安装有6轴IMU 惯性传感器、编码器、膝关节力传感器等,膝关节和踝关节都有较强的反向驱动能力,通过对电机扭矩的控制,实现对不同刚度和阻尼特性的模拟.该假肢通过24V 锂电池供电,能够以4.5km/h 的速度连续行走6.75km.2康复辅助机器人的人体运动意图识别方法意图识别,即机器人通过人体生理信息采集和分析,了解人的运动规划,进而更好地辅助其完成目标动作,包含意图测量和意图理解两个过程.2.1运动意图测量人体运动控制(Human motor control)是一个非常复杂的过程,从运动规划到运动指令的下发,再到肌肉收缩,最后到关节运动和感觉反传,涉及到中枢神经系统、外周神经系统、肌肉骨骼系统等多个复杂子系统.人的运动意图产生于大脑,却贯穿于整个运动过程,隐含在不同的子系统中,因此可以在不同层面使用不同的手段进行测量.人的运动意图与特定任务相关,尚无明确和统一的定义.最简单的意图可以是单个动作的开关或多个离散动作的切换,例如残疾人可以控制假手抓起水杯喝水,而假手的张合动作本身则由其控制器来自动完成[25];通过脑机接口(Brain machine in-terface,BMI)控制轮椅的前进、后退、左转、右转等动作[26];通过肌电假肢可以实现多自由度的复杂操作[27];穿戴式外骨骼机器人的控制也是根据用户运动意图,在站立、坐下、行走等不同种类的动作中进行选择[28].人的运动意图也可以是连续信息,例如期望的运动轨迹、关节力或力矩等.例如人的上肢够取运动(Reaching motion)满足“最小急动度(Minimal jerk)”条件[29],最终得到一条空间中的直线路径和钟形速度曲线,则可以根据当前的位置和速度预测其期望的位移;而外骨骼机器人普遍将人机交互力或力矩作为人的运动意图,控制机器人运动.如前所述,人的运动意图包含在不同的层面,因此有不同的体现形式,需要采用不同的手段进行检测.在中枢神经系统层面,可以采集脑电信号(Electroencephalogram,EEG),包括头皮脑电和植入式脑电两种;而在肌肉层面,可以采集肌电信号(Electromyography,EMG),根据电极侵入人体与否,分为表面肌电(Surface EMG,sEMG)和肌内肌电(Intramuscular EMG)两种[30−31],通过检测肌肉内部运动单元(Motor unit)的电势变化,可以反映肌肉激活程度,而且其时频信息与肌肉产生的力有较高的相关性.在骨骼关节层面,可以通过多自由度力/力矩传感器进行测量,包括3轴的交互力和3轴的交互扭矩,实现比较高的测量精度,但是成本比较高.目前比较流行的一种间接测量交互力/力矩的方式是串联弹性驱动(Serial elastic actuator,SEA)[32],将弹性元件与电机及减速器等驱动元件串联在一起,通过检测弹性元件的形变,计算得到关节扭矩或力.SEA 设计能够以较低成本实现关节力或力矩的检测,并且由于弹性元件的加入,提高了关节本身的柔顺性和交互的安全性[33],因此在康复辅助机器人研究中受到越来越多的关注.上述各种不同的测量手段有其各自不同的特点,需要根据实际情况选择合适的方案.头皮脑电可以通过用户佩戴电极帽,以非侵入的形式采集,对于截瘫、截肢等患者也适用,但是脑电信号容易受到噪声干扰[34],采集和处理过程对环境要求较高;而肌电信号的信噪比要高于脑电信号,但是仍然容易受到皮肤表面情况(汗液、毛发等)、运动伪差(Motion artifacts)、皮肤肌肉位移等因素的干扰[35−36];相对而言,力/力矩传感器信号的可靠性和精度更高,实际系统中应用也最多.但是,运动和力信息是人体运动意图的执行结果,缺少人体运动规划信息,而且在时间上相对脑电和肌电信号滞后,存在数十毫秒到数百毫秒的电机械延迟(Electromechanical de-lay)[37].因此,在设计实际系统时,需要根据这些检测手段各自的特点进行权衡,也可以将多种检测手段结合起来使用,提高检测精度和可靠性.2.2运动意图理解在对人的生理信号进行采集之后,需要运用建11期彭亮等:康复辅助机器人及其物理人机交互方法2005模方法对信号进行处理,提取其中所包含的人体运动意图信息.如前所述,目前BMI应用以机器人的离散动作控制为主,根据脑电处理结果从若干种运动类型中进行选择,进而触发假肢、轮椅、外骨骼相应的动作,常用的动作分类方法包括LDA, SVM(Support vector machines)等.肌电信号与肌肉收缩产生的力有较高的相关性,并通过肢体的动力学影响最终的运动,所以肌电信号的建模方法通常有模式分类和连续模型两种,前者通过多通道肌电信号的特征提取和模式分类,实现对假肢不同动作的控制,常用的特征包括时频特征、小波变换、AR模型等[38−39],分类方法包括LDA,SVM,神经网络等[40].通过模式识别的方法,肌电信号只用于区分有限种类的离散动作,而每个动作的执行可以由机器人自动完成,从而减小了噪声对最终控制结果的影响,在智能假肢控制中得到广泛应用.康复机器人等应用通常要求对整个人机交互过程进行调节,因此将肌电信号与连续的运动或力/力矩进行对应更加适用,即要建立两者之间的动态模型.一种方法被称作EMG驱动的神经肌肉骨骼模型(EMG-driven musculoskeletal model)[41],将肌电信号作为神经激活度的表征,输入到Hill肌肉模型,结合肌肉动力学、肌腱模型、肌肉力臂几何关系等,计算得到输出关节力矩.而当运动涉及到多块肌肉时,该方法得到的模型非常复杂,而且存在很多与个体相关的未知参数.Buchanan等[42]首先根据人体测量学统计信息对未知参数进行估计,得到一个近似模型,然后根据实际样本在近似模型的基础上进行参数的辨识.而由于肢体惯量和关节弹性等因素的影响,人在随意运动下的关节力矩无法直接测量,从而无法得到用于参数辨识的训练样本.Lloyd 等[43]在实验中,结合运动学信息(位置、速度、角速度)和肢体逆动力学模型,估计得到关节扭矩训练样本,然后使用最小二乘法对模型参数进行辨识.另一种方法是黑箱模型,只考虑输入输出关系,如Kiguchi等[44]采用自适应神经模糊控制器建立EMG幅值信号与患者估计力矩之间的关系,使用误差反传学习算法调整权值矩阵,同时考虑到肢体姿态对于EMG采集的影响,将关节角度也作为控制器的输入.在HAL机器人[45]控制中,为得到人体髋关节和膝关节的主动关节扭矩,通过将收缩肌和拮抗肌的肌电信号加权相减来估计,而权值则利用最小二乘法根据实际关节扭矩来进行辨识.文献[46]使用自适应振荡器算法从节律性变化的肌电信号中获取人重复运动的频率和相位变化,然后结合最小急动度条件,在线生成与人运动意图同步的机器人参考轨迹.3康复辅助机器人的人机交互控制方法在获取人的运动意图之后,需要根据人的运动意图进行机器人控制.在康复辅助机器人应用领域,根据人与机器人在人机交互中角色的不同,主要有主从控制模式和协作学习模式两类不同交互模式.在主从控制模式下,由人来完成运动的规划和指令的下达,而由机器人完成运动任务的执行,机器人相当于人体运动功能的代偿或增强.而在协作学习模式下,人机协作完成目标任务,机器人负责减小由人引起的控制误差,同时还要尽量鼓励人的参与,起到引导学习的目的.而随着人的运动能力的提高,机器人逐步减少对人的干预,让人更大程度地独立完成任务,实现运动学习和功能康复的目标.3.1主从控制模式的人机交互控制主从控制模式适用于智能假肢、穿戴式外骨骼、智能轮椅等应用.如前所述,通过采集肌电信号和运用模式识别方法,可以对期望的动作类型进行识别,然后由机器人执行相应的动作.机器人的运动模式可以通过编程事先确定,以固定的速度轨迹完成动作.而为了让动作执行过程更加自然平滑,并能够接受人的控制,Yatsenko等[47]在假肢执行某类动作时,采用比例控制的方式,根据肌电信号的幅值大小,调节假肢的运动速度.得益于人脑的自适应学习能力,用户可以较快地学会对机器人的控制[48],但是对人来说,这种简单的比例控制方法显然不够自然,并影响其正常的运动控制.对于穿戴式外骨骼等应用,机器人控制变量通常是位置,在测量或估计得到人机交互力后,可以将其转化为期望的运动轨迹.Ge等[49]将人的运动控制策略假设成质量–弹簧–阻尼形式的线性阻抗,则人的目标位置为弹簧的平衡位置.阻抗控制在机器人中的应用首先由Hogan[50]提出,是机器人刚度控制的扩展.阻抗控制方法针对机器人与环境交互任务,使用质量、阻尼、弹簧等阻抗模型来刻画交互接口的作用力和运动结果之间的动态特性.阻抗控制有两种实现形式,一种根据运动偏差检测来控制机器人输出力,适用于具有较强反向驱动能力的机构,广泛应用于力反馈设备中,MIT-Manus上肢康复机器人也是采用的阻抗控制方法;另一种实现形式是检测交互力来控制机器人位置与弹簧平衡位置之间的偏差,也被称作导纳控制或基于位置的阻抗控制.对于大多数机器人,位置伺服更容易实现,因此基于位置的阻抗控制得到广泛应用.动力型膝上假肢控制中常用一种称为有限状态阻抗(Finite state impedance,FSI)控制[51]的方法.FSI控制基于当前的步态相位调整假肢关节的阻抗,以模拟正常人体膝关节在运动中的动力学特。
华支睾吸虫囊蚴RPA检测方法的建立
中国兽医科学 2021,51(04): 441-445Chinese Veterinary Science网络首发时间：2021-01-26 D O I：10.16656/j.issn. 1673-4696.2021.0066 中图分类号：S852.735 文献标志码：A 文章编号：1673-4696(2021)04-0441-05华支睾吸虫囊蚴RPA检测方法的建立张春玲，邱阳元，郝朔，白雪，刘明远，张藜潇'刘晓雷* (吉林大学人兽共患病研究所人兽共患病研究教育部重点实验室，吉林长春130062)摘要：为了建立灵敏、快速的鉴别华支睾吸虫诊断方法，本研究根据华支睾吸虫囊蚴的C O X-1基因序 列设计引物，建立检测华支睾吸虫囊蚴的R P A方法。
结果显示：所建立的R P A的灵敏度可达到2.75 ng/y L,而与日本血吸虫、隐孢子虫、阔节裂头绦虫、东方次睾吸虫囊蝴、台湾次睾吸虫囊蚴、异尖线虫和棘颚口线虫 均无交叉反应；经条件优化后，可在35 °C下5 m i n内观察到检测结果。
另外，在对实际样品检测中，通过添加 核酸染料SYBR Green I,无需P C R仪及紫外凝胶系统的条件下，可以快速地鉴别出华支睾吸虫囊蚴及虫卵。
结论，本研究成功地建立了华支睾吸虫囊蚴P R A检测方法，这在食品安全检测中具有重要的应用前景。
关键词：华支睾吸虫；囊蚴；R P A;C O X_l;特异性；灵敏性Development of RPA assay for the detection ofClonorchis sinensis metacercariaZHANG Chun-ling,QIU Yang-yuan,HAO Shuo.BAI Xue.LIU Ming-yuan,ZHANG Li-xiao* ,LIU Xiao-lei* (Key laboratory of Z oonosis Research of M inistry of E ducation / Institute of Z oonosis ,J i l i n University yChangchun 130062, China)Abstact：In order to establish a sensitive and efficient diagnostic method to identify Clonorchis sinensis,in this study,the primers were designed based on C0X-1 gene sequence of Clonorchis sinensis metacercaria,and the detection method of recombinase polymerase amplification (RPA) for Clonorchis sinensis metacercaria was been established. The results showed that the sensitivity of RPA reached 2.75 n g/u L and RPA was specificity,and there were no cross-reacts with Schistosoma japonicumfCryp-tosporidium，Diphyllobothriuin latum，0rientia oriental is，Hypotremes taiwan，Anisakis and Gnathostoma siamense.After optimization,the test results were been observed within 5 minutes at 35 °C. In addition, with the SYBR Green I acid dye addition, the Clonorchis sinensis metacercaria and eggs were been identified rapidly even if with no PCR or UV gel system. Thus,the PRA detection method of Clonorchis sinensis metacercariae was successfully been established in this study,which had important application prospects for food safety detection.Key word：Clonorchis si/iensis；metacercaria；RPA；COX-1 ；specificity；sensitivity* Corresponding authors：Z H A N G Li-xiao，E-mail:************.cn;LIU Xiao-lei,E-mail:***************华支睾吸虫病是一种危害严重的食源性人兽 虾而引起感染。
信息安全 英语作文
In the modern era,information security has become a paramount concern for individuals and organizations alike.With the rapid advancement of technology,the digital landscape has expanded,and so has the risk of data breaches and cyberattacks. Here are some key points to consider when discussing the importance of information security in an English essay:1.Definition of Information Security:Begin by defining what information security entails. It is the practice of protecting digital information from unauthorized access,use, disclosure,disruption,modification,or destruction.2.Importance in the Digital Age:Explain how the reliance on digital systems for personal and professional purposes has made information security crucial.Discuss the consequences of inadequate security measures,such as identity theft,financial loss,and reputational damage.3.Types of Cyber Threats:Enumerate the various types of cyber threats that exist, including malware,phishing,ransomware,and social engineering.Provide examples of how these threats can compromise information security.4.Individual Responsibility:Discuss the role of individuals in maintaining information security.This includes using strong passwords,being cautious with email attachments, and being aware of phishing attempts.anizational Measures:Describe the measures that organizations can take to ensure information security.This may involve implementing firewalls,intrusion detection systems,data encryption,and regular security audits.6.Legal and Regulatory Frameworks:Mention the role of laws and regulations in promoting information security.Discuss how legislation such as the General Data Protection Regulation GDPR in the European Union and the California Consumer Privacy Act CCPA in the United States aim to protect personal data.7.Technological Solutions:Explore the technological solutions available to enhance information security.Discuss the use of antivirus software,secure network protocols,and multifactor authentication.cation and Awareness:Stress the importance of education and awareness in combating cyber threats.Explain how regular training sessions and awareness campaigns can help individuals and organizations recognize and respond to security threats.9.Ethical Considerations:Address the ethical implications of information security. Discuss the balance between privacy rights and the need for surveillance to prevent cybercrime.10.Future Challenges and Prospects:Conclude by looking at the future of information security.Discuss emerging technologies such as artificial intelligence and blockchain, and how they might impact the field of information security.Remember to structure your essay with a clear introduction,body paragraphs that explore each point in detail,and a conclusion that summarizes the main ideas and possibly suggests further steps for enhancing information e examples and case studies to support your arguments and make your essay more engaging.。
学术英语理工综述范文
学术英语理工综述范文篇1Quantum computing is undoubtedly one of the most revolutionary technologies in the field of science and engineering! It has brought about a paradigm shift in our understanding of computing and information processing. The key theoretical breakthroughs in quantum computing are truly astonishing. The principles of superposition and entanglement have opened up new horizons, allowing for the processing of vast amounts of data simultaneously. This has led to significant advancements in areas such as cryptography and optimization problems.In terms of practical applications, quantum computing has already shown promising results in drug discovery and financial modeling. However, we are still at an early stage. Many challenges remain, such as the issue of error correction and scalability.So, what does the future hold for quantum computing? Will it completely transform our lives in the coming decades? The possibilities seem endless! But we need to continue investing in research and development to fully unlock its potential. It's an exciting time for the field of quantum computing, and we can't wait to see what lies ahead!篇2The application of artificial intelligence in the medical field hasemerged as a revolutionary force in recent years! It holds tremendous potential for improving healthcare outcomes and transforming medical practices.Numerous studies have shown remarkable results. For instance, AI-powered diagnostic tools can analyze medical images with high accuracy, assisting doctors in early disease detection. However, there are significant challenges. The reliability and interpretability of AI algorithms remain concerns. What if the algorithms make incorrect predictions? And how can we ensure patient data privacy in the process?Possible solutions include rigorous validation and testing of AI systems. Also, transparent explanations of algorithm decisions are crucial. Moreover, strict data protection regulations must be in place.In conclusion, while the prospects of AI in healthcare are exciting, addressing these issues is essential for its widespread and safe adoption.篇33D printing has emerged as a revolutionary technology in the manufacturing sector! It has brought about remarkable changes and opened up new possibilities. In the aerospace industry, it enables the production of complex and lightweight components, enhancing the performance of aircraft. In the medical field, custom-made prosthetics and implants are created with precision, improving patients' quality of life. However, it's not all smooth sailing. The high cost of equipment and materials poses asignificant challenge. Also, the quality control of printed products needs to be further enhanced. How can we overcome these obstacles and fully unleash the potential of 3D printing? The need for continuous research and development is crucial. Despite the challenges, the future of 3D printing in manufacturing looks incredibly promising. Isn't it exciting to think about the endless possibilities it holds?篇4Renewable energy conversion and storage have emerged as a crucial topic in the field of science and engineering! The development of efficient and sustainable energy systems is of paramount importance for our future. Current research has made significant progress in technologies such as solar cells and lithium-ion batteries. However, there are still numerous challenges that need to be addressed. For instance, the efficiency of solar cell conversion remains relatively low, and the lifespan and cost of lithium-ion batteries pose significant limitations. How can we improve the performance and reduce the cost of these technologies? This is a pressing question. Potential research directions include exploring new materials and developing advanced manufacturing processes. The quest for clean and sustainable energy is ongoing, and it demands continuous innovation and dedication. Isn't it exciting to think about the possibilities that lie ahead in this field?篇5In the vast realm of materials science, remarkable advancements have been witnessed! The improvements in material properties are truly astonishing. Take graphene, for instance. Its superior conductivity and strength have opened up new horizons in electronics and aerospace. The enhanced durability and flexibility of certain alloys have revolutionized the automotive and manufacturing industries.The application expansion of these advanced materials is mind-blowing. They are now being used in medical devices, energy storage systems, and even in sustainable construction. But what lies ahead for the market? The potential seems limitless! With growing demands for lightweight, high-performance materials, the future market outlook is incredibly promising.However, challenges remain. How to mass-produce these materials cost-effectively? And how to ensure their safety and reliability in various applications? These questions need urgent answers as we forge ahead in this exciting field of materials science.。
detection verification 感叹号
Detection Verification: A Comprehensive OverviewIntroductionDetection verification is a crucial process in various fields, including security, technology, and healthcare. It involves the identification and confirmation of detected objects or events to ensure accuracy and reliability. This article provides a comprehensive overview of detection verification, including its definition, applications, techniques, challenges, and future prospects.DefinitionDetection verification refers to the process of confirming the presence or absence of an object or event identified by a detection system. It aims to minimize false positives and false negatives by validating the detection results through additional analysis or human intervention. The ultimate goal is to enhance the reliability and trustworthiness of detection systems.ApplicationsSecurityDetection verification plays a vital role in security systems such as surveillance cameras, access control systems, and intrusion detection systems. By verifying detected events like potential threats or unauthorized access attempts, security personnel can quickly respond to real incidents while minimizing false alarms.TechnologyIn the field of technology, detection verification is used in various areas such as computer vision, natural language processing (NLP), and machine learning. For example, in computer vision applications like object recognition or facial recognition systems, verification techniques are employed to confirm the accuracy of detected objects or individuals.HealthcareIn healthcare settings, detection verification is essential for medical imaging techniques such as X-rays and MRIs. Radiologists useverification methods to ensure accurate identification of abnormalities or diseases in patients’ scans. This helps in providing precise diagnoses and appropriate treatments.Techniques for Detection Verification1.Manual Verification: Human experts manually review the detectedobjects or events to confirm their presence or absence. Thistechnique ensures high accuracy but can be time-consuming andsubjective.2.Rule-based Verification: Predefined rules are applied to verifythe detected objects or events based on specific criteria. Forexample, an intrusion detection system may verify an alarm bychecking if multiple sensors have triggered simultaneously.3.Machine Learning Verification: Machine learning algorithms aretrained to verify the detection results based on a labeled dataset.The algorithms learn patterns and characteristics of truepositives and negatives, improving the accuracy of verification. 4.Statistical Analysis: Statistical methods are used to analyze thedetection results and calculate probabilities or confidence levels.By setting appropriate thresholds, verification can be performedbased on statistical significance.Challenges in Detection Verificationplex Environments: Detection verification becomes challengingin complex environments with high levels of noise, occlusions, oroverlapping objects. These factors can lead to false detectionsand require sophisticated techniques for accurate verification.2.Real-time Verification: In applications where real-time responseis critical, such as security systems, performing efficientverification within tight time constraints can be challenging.Fast and reliable algorithms are required to ensure timelyresponses.3.Adversarial Attacks: Malicious actors may attempt to deceivedetection systems by introducing adversarial inputs thatmanipulate the detection results. Detecting and verifying suchattacks pose significant challenges for detection verificationtechniques.4.Scalability: As the volume of data increases, scalability becomescrucial for efficient detection verification. Handling largedatasets in real-time while maintaining high accuracy is achallenge that needs to be addressed.Future ProspectsDetection verification is an evolving field with promising future prospects. Advances in machine learning, deep learning, and artificial intelligence will contribute to more robust and accurate verification techniques. Additionally, the integration of multiple sensors and data fusion techniques will enhance the reliability of detection systems.Furthermore, research efforts should focus on addressing the challenges posed by complex environments and adversarial attacks through innovative algorithms and robust architectures. Collaborative studies between academia, industry, and government entities can accelerate advancements in detection verification technology.In conclusion, detection verification plays a critical role in ensuring the accuracy and reliability of detected objects or events across various domains such as security, technology, and healthcare. By employing different techniques and overcoming challenges, detection verification contributes to enhanced decision-making processes and improved overall system performance.Note: This article provides a comprehensive overview of detection verification. However, due to the requirement of avoiding sensitive topics or vocabulary in China, some specific examples or discussions related to these topics have been omitted.。
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A. Galli1 and L. Piro1
IASF-Roma/INAF, via fosso del cavaliere 100, 00133 Roma, Italy
Received —; accepted —
Abstract. The detection of the 100 GeV-TeV emission by a Gamma-Ray Burst (GRB) will provide an unprecedented opportunity to enlighten the nature of the central engine and the interaction between the relativistic flow and the environment of the burst progenitor. In this paper we show that there are exciting prospects of detecting by MAGIC high energy (HE) emission from the burst during the ”early” X-ray flaring activity and, later, during the ”normal” afterglow phase. We also identify the best observational strategy (trigger conditions and time period of observation). We determine the expected HE emission from the flaring and afterglow phases of GRBs in the context of the External Shock scenario and compare them with the MAGIC threshold. We find that a X-ray flare with the average properties of the class, can be detected in the 100 GeV range by MAGIC provided that z <1. The requested observational window with MAGIC should then start from 10-20 sec after the burst and cover about 1000-2000 sec. Furthermore, we demonstrate that there are solid prospects to detect the late afterglow emission in the same energy range for most of the bursts with z <1 if the density of the external medium is n a few cm−3. In this case the MAGIC observation shall extend to about 10 - 20 ksec. We provide recipes to tailor this prediction to the observational properties of each burst, in particular the fluence in the prompt emission and the redshift, thus allowing an almost ”real time” decision procedure to decide whether to continue the follow up observation of a burst at late times.
Send offprint requests to: A. Galli: alessandra.galli@iasf-roma.inaf.it
by inverse Compton (IC) into the GeV-TeV range (Sari & Esin 2001; Zhang & Meszaros 2001), i.e in the observational band of MAGIC. Very interestingly it as been shown that IC from the afterglow of a ”standard ” thin shell fireball could explain the delayed (∼ 5000 sec after the burst) HE (MeV-to-GeV) emission observed by EGRET in GRB 940217 (Galli & Piro 2007). In this letter we show that MAGIC should be able to the detect the late HE emission from afterglow of GRBs.
Astronomy & Astrophysics manuscript no. ms (DOI: will be inserted by hand later)
May 19, 2008
arXiv:0805.2884v1 [astro-ph] 19 May 2008
Prospects for detection of very high energy emission from GRB in the context of the External Shock model
Key s. Gamma-rays: bursts
1. Introduction
Prompt and afterglow emission in GRBs show different temporal and spectral properties and are usually attributed to different mechanisms, more specifically, internal and external shocks respectively. The internal shocks (IS) occur within the relativistic outflow released after the burst explosion, and an external shock (ES) starts to develop when the ejecta expands in the external medium. The shock with the external medium develops through two components, a forward shock (FS) propagating in the external medium ahead the expanding shell, and a reverse shock (RS) moving back into the shell itself (Meszaros & Rees 1993). During its expansion into the external medium the fireball collects an increasing amount of the external material. When the inertia of this material equals the fireball energy, the fireball starts to decelerate. The properties of the FS and the RS strongly depend on the GRB duration TGRB with respect to the fireball deceleration time tdec. In the standard scenario (i.e. thin shell fireball) the burst duration is shorter than the fireball deceleration time. In this case the RS ends crossing the outflow before the fireball starts to decelerate, thus the fireball releases most of its energy to the external medium, and the ES reaches the peak of its emission, at tdec. This ES produces synchrotron radiation - i.e afterglow emission - in the X-ray-to-MeV range. This radiation then can be up-scattered