Microwave and THz applications of ferroelectrics and multiferroics
光纤传感及太赫兹应用技术
光纤传感及太赫兹应用技术英文回答:Fiber Optic Sensing and THz Applications.Fiber optic sensing is a rapidly growing field that utilizes optical fibers to measure physical and chemical parameters. Fiber optic sensors offer a number of advantages over traditional sensors, including high sensitivity, immunity to electromagnetic interference, and the ability to operate in harsh environments.One of the most important applications of fiber optic sensing is in the field of telecommunications. Fiber optic sensors are used to monitor the performance of optical fiber networks and to detect faults. They are also used in medical applications, such as endoscopy and surgery, to provide real-time monitoring of vital signs.Terahertz (THz) technology is another rapidly growingfield that offers a number of potential applications. THz waves are electromagnetic waves that fall between the microwave and infrared regions of the spectrum. They have a number of unique properties, including the ability to penetrate materials that are opaque to other forms of radiation, and the ability to excite molecular vibrations.THz technology has a number of potential applicationsin the fields of security, imaging, and communications. For example, THz waves can be used to detect concealed weapons and explosives, and to image through walls and other opaque materials. They can also be used to transmit high-speed data over wireless links.The combination of fiber optic sensing and THz technology has the potential to create a new generation of sensors and devices that can be used in a wide variety of applications. For example, fiber optic THz sensors could be used to monitor the performance of optical fiber networks, to detect faults, and to image through opaque materials. They could also be used in medical applications, such as endoscopy and surgery, to provide real-time monitoring ofvital signs.中文回答:光纤传感及太赫兹应用技术。
宽频段太赫兹大气传输特性的理论与实验研究
摘要太赫兹波在电磁波谱中位于微波和红外波之间,具有瞬态性、宽带性、低能量性、透射性等优点,在分子光谱、生物医学、空间通信、大气遥感和雷达探测等领域有广阔的应用前景。
太赫兹波在大气中的传输特性是太赫兹波空间应用的基础,研究不同温度、湿度、大气压强和海拔高度等条件下太赫兹波的大气衰减系数,找到透过率窗口的位置和宽度对于促进该频段在空间中的应用具有重要意义。
本文的研究内容可以归纳如下:1、介绍了太赫兹波的空间应用以及研究太赫兹波大气传输特性的重要性,并综述了太赫兹波大气传输特性的国内外发展历史和研究现状。
2、根据HITRAN数据库中的光谱参数,用逐线计算方法计算了水蒸气和氧气的谱线吸收,用MT_CKD模型计算了水蒸气的连续吸收。
考虑到气温、气压和相对湿度对吸收系数的影响,比较了0~8 THz 的太赫兹波的吸收系数随这三个因素的变化,并给出了大气窗口的频率。
通过对不同海拔高度的吸收系数进行计算,分析了高频太赫兹波在高空尤其是平流层中远距离传输的可行性。
3、根据米氏散射理论对气溶胶粒子的散射特性参数进行计算,以此为基础在高能见度天气中计算太赫兹波的单次散射衰减,在低能见度天气中用蒙特卡罗法解决多次散射问题。
并且分析了我国海雾和内陆雾以及塔克拉玛干沙漠和毛乌素沙漠中太赫兹波的衰减、散射、透过率情况。
4、在实验室环境下用远红外傅里叶光谱仪(FTIR)搭建了太赫兹波大气传输特性实验平台,测量了不同压强和湿度条件下0.5 THz~7.5 THz 频段的太赫兹波传输2.3 m的透过率,用比尔-朗伯定律反推大气吸收系数,实验结果与理论计算结果吻合得很好。
关键词:太赫兹波,吸收系数,蒙特卡罗法,FTIRABSTRACTTerahertz (THz) spectral range which falls between microwave and infrared, has many advantages, such as transient, broadband, low photon energy and transmission. And THz wave can be widely applied in spectroscopy, biomedical science, free-space based communication, remote sensing, radar and so on. The transmission characteristics of THz wave is the basis of THz free-space applications. To research THz atmospheric attenuation coefficients under different conditions (e.g. temperature, relative humidity, pressure, altitude etc ) and to find the locations and widths of atmospheric transmission windows will be important for THz free-space applications.The main contents of this dissertation are as follows:1. THz free-space applications, and the importance of research on terahertz atmospheric transmission characteristics are introduced. The development and present developing status of this problem are also summarized.2. Line absorption of water vapor and oxygen is calculated based on line-by-line calculations and the spectral parameters in HITRAN database. And water vapor continuum absorption is calculated based on MT_CKD model. Considering temperature, pressure and relative humidity, broadband THz atmospheric transmission characteristics from 0 to 8 THz is theoretically simulated. Atmospheric transmission windows in this range are also given. Based on absorption coefficients in different altitudes, the high frequency atmospheric windows are evaluated and the feasibility for long-range applications is estimated.3. The scattering characteristics of air aerosol are calculated based on Mie theory. According to these results, terahertz attenuation characteristics are studied for single scattering of particles in high-visibility environment and multiple scattering in low-visibility environment using Monte-Carlo method. Terahertz attenuation coefficients, scattering characteristics and transmittance are analyzed in real environment including sea fog, inland fog, Taklimakan Desert and Mu Us Desert.4. An experimental system is built based on a Fourier transform infrared spectrometer (FTIR) in laboratory. Considering the influence of water concentrationand pressure, the terahertz transmission is measured from 0.5~7.5 THz with 2.3-m path length. The absorption coefficients are calculated according to Beer-Lambert Law, which are consistent with calculation results.KEY WORDS:THz Wave, Absorption Coefficients, Monte-Carlo, FTIR目录摘要 (I)ABSTRACT ................................................................................................................. I I 第1章绪论 .. (1)1.1 太赫兹波简介 (1)1.1.1 太赫兹波的特点 (1)1.1.2 太赫兹波的空间应用及大气传输特性研究的意义 (2)1.2 国内外研究进展 (4)1.2.1 太赫兹波大气吸收特性的研究进展 (4)1.2.2 太赫兹波大气散射特性的研究进展 (7)1.3 本文主要内容 (8)第2章宽频段太赫兹波的大气吸收 (9)2.1 大气分子的选择吸收 (9)2.1.1 大气分子光谱 (9)2.1.2 谱线的增宽 (10)2.1.3 吸收系数和透过率 (10)2.2 大气分子光谱参数数据库——HITRAN (11)2.2.1 HITRAN数据库中的光谱参数 (11)2.2.2 光谱参数随温度和压强的变化 (12)2.2.3 吸收系数的计算 (13)2.3 主要大气成分对太赫兹波的吸收 (13)2.3.1 水蒸气和氧气的太赫兹吸收谱 (13)2.3.2 连续吸收 (15)2.3.3 吸收系数随温度、大气压强、相对湿度的变化情况 (17)2.4 不同海拔高度太赫兹波的传输衰减 (21)2.4.1 大气的物理概况 (21)2.4.2 大气吸收系数和太赫兹波透过率随海拔高度的变化 (22)2.4.3 太赫兹波垂直入射时的透过率 (25)2.5 本章小结 (26)第3章太赫兹波在复杂大气背景下的散射特性 (27)3.1 单个球形粒子的散射理论 (27)3.1.1 散射过程 (28)3.1.2 米散射理论 (29)3.2 单次散射理论 (30)3.3 多次散射的处理——蒙特卡罗法 (31)3.4 太赫兹波在雾中的散射特性 (33)3.4.1 雾的物理特性 (33)3.4.2 太赫兹波在雾中的单次散射 (35)3.4.3 太赫兹波在低能见度雾中的多次散射 (37)3.5 太赫兹波在风沙天气中的散射特性 (39)3.5.1 我国沙漠地区中沙尘的物理特性 (39)3.5.2 太赫兹波在扬沙天气中的单次散射 (41)3.5.3 太赫兹波在沙尘暴天气中的多次散射 (43)3.6 本章小结 (45)第4章太赫兹波大气传输特性实验 (47)4.1 太赫兹波大气传输特性实验平台设计 (47)4.2 实验结果与分析 (49)4.2.1 实验中湿度和压强对太赫兹波透过率的影响 (49)4.2.2 实验与理论计算结果比较分析 (51)4.2.3 存在问题及建议 (52)4.3 本章小结 (53)第5章总结与展望 (55)参考文献 (57)发表论文和参加科研情况说明 (63)致谢 (65)第1章绪论1.1 太赫兹波简介太赫兹波的频率范围是0.1 THz~10 THz(波长3mm~ 30μm),在电磁波谱中介于微波和红外波之间,如图1-1所示。
微波工程第三版英文原版pptch10
Figure 10-18 (p. 507)
Third-order intercept point for a cascaded system. (a) Two cascaded networks. (b) Equivalent network.
Microwave Engineering, 3rd Edition by David M. Pozar Copyright © 2004 John Wiley & Sons
Figure 10-13 (p. 501)
A general nonlinear device or network.
Microwave Engineering, 3rd Edition by David M. Pozar Copyright © 2004 John Wiley & Sons
Figure 10-14 (p. 503)
Figure 10-7 (p. 493)
Determining the noise figure of a noisy network.
Microwave Engineering, 3rd Edition by David M. Pozar Copyright © 2004 John Wiley & Sons
Definition of the 1 dB compression point for a nonlinear amplifier.
Microwave Engineering, 3rd Edition by David M. Pozar Copyright © 2004 John Wiley & Sons
ห้องสมุดไป่ตู้
Figure 10-19 (p. 508)
球型目标在不同波段的雷达散射截面
球型目标在不同波段的雷达散射截面杨洋;姚建铨;宋玉坤;邴丕彬;李忠洋【摘要】文中对球型目标在微波、红外、太赫兹等不同波段的雷达散射截面进行深入探讨,利用电磁波理论和红外辐射理论得到了理想金属球的微波雷达和朗伯球的激光雷达的散射截面的数学表达式,并在此基础上给出了球型目标太赫兹雷达散射截面的具体研究内容和研究方式,指出选用理想金属朗伯球体的目标作为太赫兹雷达散射截面的标准体,提出了"中值加权修正"的研究方法,并对方法的具体实施方案给予了阐述.%The radar scattering cross section of microwave, laser and terahertz in different wave band for spherical targets are investigated. By using electromagnetic theory and infrared radiation theory, the mathematical expression of radar scattering cross section are given in microwave radar of ideal metal ball and laser radar of Lambert wave. Then the specific research and method of terahertz radar scattering cross section for spherical targets are obtained. The "median weighted correction method" and its concrete implementation are presented by chosen the ideal metal Lambertian sphere as the standard body of terahertz radar scattering cross section.【期刊名称】《激光与红外》【年(卷),期】2011(041)005【总页数】5页(P552-556)【关键词】微波雷达;激光雷达;太赫兹雷达;雷达散射截面;球型目标【作者】杨洋;姚建铨;宋玉坤;邴丕彬;李忠洋【作者单位】天津大学精密仪器与光电子工程学院激光与光电子研究所,天津300072;承德石油高等专科学校,河北承德067000;天津大学精密仪器与光电子工程学院激光与光电子研究所,天津300072;承德石油高等专科学校,河北承德067000;天津大学精密仪器与光电子工程学院激光与光电子研究所,天津300072;天津大学精密仪器与光电子工程学院激光与光电子研究所,天津300072【正文语种】中文【中图分类】TN95雷达散射截面是一个用以表述目标截获和反射辐射功率能力的物理量,它在目标识别、目标成像中具有重要作用。
NOVEL MICROPEPTIDE HMMW AND APPLICATION THEREOF
专利名称:NOVEL MICROPEPTIDE HMMW ANDAPPLICATION THEREOF发明人:XU, Hanmei,LI, Mengwei申请号:EP20860427.2申请日:20201103公开号:EP4006048A2公开日:20220601专利内容由知识产权出版社提供专利附图:摘要:The present invention provides a micropeptide HMMW of a new structure and an application thereof, and relates to the field of biomedical research and development.The micropeptide HMMW is obtained by encoding human IncRNA, and a recombinantvector is constructed so that objective cells perform high expression on the micropeptide HMMW, which can inhibit proliferation and migration of multiple solid tumors including the head and neck cancer, thyroid cancer, lung cancer, esophageal squamous cellcarcinoma, stomach cancer, breast cancer, kidney cancer, skin cancer and the like, and growth of tumors in the body. The micropeptide HMMW has potential value for new drug development, important tumor detection and treatment value.申请人:Nanjing Anji Biotechnology Co., Ltd.地址:6F HongFeng Technology Park A7 Economic-Technological Development Area Qixia District Nanjing, Jiangsu 210038 CN国籍:CN代理机构:Kramer Barske Schmidtchen Patentanwälte PartG mbB更多信息请下载全文后查看。
CMOS微波射频芯片任意温度系数自适应补偿技术及芯片设计
Vol. 44 No. 2Apr. 2021第44卷第2期2021年4月电子器件Chinese Journal of ElccLmn DevicesDiscretional Coefficient Self-Adaptive TemperatureCompensation on CMOS RF and MMICs *ZHANG Meng 1 '2, CHEN Ziran 1^2, HE Ning 1 '2(1. Aerospace Science and Industry Academy qf Communication Technology , Chengdu Sichuan 610051 , China ;2. Joint Institute of Quantum Information and Communication SEU and AS1ACT ,Nanjing Jiangsu 211100, China)Abstract :CMOS chips are widely favored for its cost advantages in Lhe design and manufacturing, and with Lhe process nodes enhancing their coverage has reached microwave and THz frequencies. However , the performance of the CMOS amplifiers distinctly decline on high temperature due to the open-loop topology . The traditional approach can not realize the discretional coefficient temperature compensation. A new technology on self-adaptive temperaturecompensation is provided. An L-band CMOS amplifier to achieve positive coefficient self-adaptive temperature compensation is designed . The test results show that at the compensation points of 25 兀 and 65 兀,5 dB and 10 dBgain compensation is achieved . The technology can extend to discretional coefficient , range , level and RF bands to enhance the utility of RF CMOS chips.Key words :CMOS RF and MMICs ;self-adaptive temperature compensation ; discretional coefficientEEACC :7320G doi :10 ・3969/j ・issn ・1005-9490・2021 ・02・002CMOS 微波射频芯片任意温度系数自适应补偿技术及芯片设计*张萌陈自然何宁(1.航天科工通信技术研究院有限责任公司,四川成都610051;2.东南大学航天科工通信技术研究院量子信息与通信联合研究中心,江苏南京211100)摘要:CMOS 芯片以其成本优势在设计制造中得到广泛青睐,伴随着工艺节点的提升,其频率覆盖范围已达到微波及太赫兹频段。
广播电视微波通信技术及运用分析
DCWTechnology Analysis技术分析107数字通信世界2023.05随着科学技术的飞速发展,数字化微波通信技术愈加成熟,将其应用于广播电视行业,可以提高广播电视信号的传输质量,为观众带来良好的视听感受,推动广播电视行业稳定可持续发展。
现阶段,研究数字化微波通信技术,成为推动数字化广播行业发展的重要举措。
因此,研究此项课题,具有十分重要的意义。
1 微波通信技术的应用优势1.1 信号传播能力强收发信号设备、反馈设备等是微波通信系统的重要组成部分。
在广播信号传输过程中,其波段频率可达300 GHz ,微波的波长范围为1 mm ~1 m ,微波通信技术受地形、阻隔物、空间等因素的影响较小,因此,利用微波搭载传输广播电视信号,可以提升信号传输准确度,因此,此类信号传输方式,受到广播电视行业的欢迎。
具体来说,采用微波通信技术,先将广播电视信号发送给信号中心,由信号中心对信号内容进行监控,在保证信号安全性的基础上,将信号传输给各分卫星,然后由卫星系统将信号传输到接收端,卫星系统信号承载量相对较大,因此,在应用卫星系统,完成广播电视信号传输工作时,被传输信号能同时满足多个客户的需要。
在偏远及环境恶劣的地区,若采用传统的线缆传输方式,会因线缆架设难度大,导致广播信号传播成本大幅度提升。
而利用微波点对点、点对多的方式完成信号传输工作,不仅可以扩大广播电视业务的覆盖范围,还能降低广播电视信号的传输成本。
相较于普通线缆,利用微波通信技术传播广播电视信号的成本低,并且在后期维护抢修过程中,有利于降低抢修工作的难度与成本。
例如,在地震发生时,若广播电视信号传输方式为传统光纤通信方式,则传输信号的光纤可能会在地震中出现断裂,导致信号传输中断,不仅无法满足人们获取广播电视节目的需要,还会花费大量的人力物力及时间,对线路进行修复。
而对于微波通信技术而言,发生地震,即便广播电视信号出现短暂中断,相关工作人员仅需分析线路通信情况,通过对准收发天线的方式,即可完成几百兆甚至几千兆的广播电视数据传输与接收,在满足人们对信号获取需要的基础上,缩短信号传输线路恢复所消耗的时间、降低修复工作的成本。
第46_届国际红外毫米波与太赫兹会议综述:太赫兹辐射源的最新研究进展
第 21 卷 第 11 期2023 年 11 月Vol.21,No.11Nov.,2023太赫兹科学与电子信息学报Journal of Terahertz Science and Electronic Information Technology第46届国际红外毫米波与太赫兹会议综述:太赫兹辐射源的最新研究进展郑文杰,吴振华*,张晓秋艳*,赵陶,钟任斌,刘頔威,魏彦玉,宫玉彬,胡旻(电子科技大学电子科学与工程学院,四川成都611731)摘要:太赫兹波段介于微波与红外之间,具有许多独特的优势,如对许多物质的穿透能力、较低的光子能量等。
这使得太赫兹技术在生物医学、安全检测、通信等领域具有广泛的应用前景。
太赫兹辐射源是太赫兹技术的核心组件,其发展水平直接决定了太赫兹技术在各个应用领域的性能和前景。
第46届国际红外毫米波与太赫兹会议聚焦了太赫兹辐射源的最新研究成果,展示了在新型辐射源、集成技术及优化设计等方面的重要进展。
本文根据近段时间红外毫米波与太赫兹相关国际关会议报告的内容,总结并展示了不同类型太赫兹辐射源最前沿的研究内容与方向。
这些成果为太赫兹技术在各个应用领域的进一步发展奠定了坚实基础。
关键词:太赫兹技术;辐射源;第46届国际红外毫米波与太赫兹会议中图分类号:O441.4 文献标志码:A doi:10.11805/TKYDA2022042 Review of theReview of the 4646th international conference on infrared millimeter waves and th international conference on infrared millimeter waves and terahertzterahertz:: recent research advances in terahertz radiation sourcesZHENG Wenjie,WU Zhenhua*,ZHANG Xiaoqiuyan*,ZHAO Tao,ZHONG Renbin,LIU Diwei,WEI Yanyu,GONG Yubin,HU Min(School of Electronic Science and Engineering,University of Electronic Science and Technology of China,Chengdu Sichuan 611731,China) AbstractAbstract::The terahertz band is between microwave and infrared and has many unique advantages, such as the ability to penetrate many substances and lower photon energy. This makesterahertz technology promising for a wide range of applications in the fields of biomedicine, securitydetection, and communications. Terahertz radiation source is the core component of terahertztechnology, and its development level directly determines the performance and prospect of terahertztechnology in various applications. The 46th International Conference on Infrared Millimeter Wavesand Terahertz focuses on the latest research results of terahertz radiation sources and demonstratesimportant progress in new radiation sources, integration technology and optimized design. This papersummarizes and shows the cutting-edge research content and directions of different types ofterahertz radiation sources based on the reports of recent international conferences related toinfrared millimeter wave and terahertz. These results lay a solid foundation for the furtherdevelopment of terahertz technology in various applications.KeywordsKeywords::terahertz technology;radiation sources;the 46th international conference on infrared millimeter waves and terahertz1 太赫兹辐射源简介太赫兹(THz)技术,在0.1~10 THz的频率范围内运行,近年来获得了极大的关注,因为它有可能彻底改变各个领域,如成像、通信、安全和感应。
我研究微波遥感的英语作文
我研究微波遥感的英语作文Microwave remote sensing is a powerful tool used to gather information about the Earth's surface and atmosphere. It involves the use of microwave radiation to measure various properties of the target, such as temperature, moisture content, and surface roughness. This technologyhas revolutionized our understanding of the Earth and has numerous applications in weather forecasting, agriculture, and environmental monitoring.Microwave remote sensing works by emitting microwave radiation towards the target and measuring the reflected or emitted radiation. The interaction between the microwave radiation and the target provides valuable informationabout its properties. For example, the amount of radiation reflected by a surface can indicate its roughness, whilethe intensity of the emitted radiation can reveal the temperature of an object.One of the advantages of microwave remote sensing isits ability to penetrate through clouds, vegetation, and even some building materials. This allows researchers to gather data in areas that are otherwise inaccessible or obscured by other factors. For example, microwave remote sensing can be used to monitor soil moisture levels in agricultural fields, providing valuable information for farmers to optimize irrigation practices.Another application of microwave remote sensing is in monitoring sea ice and polar regions. By measuring the microwave radiation emitted by sea ice, scientists can track its extent and thickness, providing crucial information for climate studies and navigation purposes. This technology has also been used to monitor changes in glaciers and ice sheets, helping us understand the impact of climate change on these vulnerable regions.In addition to its applications on Earth, microwave remote sensing is also used for planetary exploration. Spacecraft equipped with microwave sensors have been sent to other planets, such as Mars, to study their surface composition and geological features. By analyzing themicrowave radiation reflected or emitted by these planets, scientists can gain insights into their physical properties and potential for supporting life.In conclusion, microwave remote sensing is a versatile and valuable technology that allows us to gather information about the Earth's surface and atmosphere. Its ability to penetrate through various obstacles and its wide range of applications make it an essential tool in many fields of research. As technology continues to advance, we can expect even more exciting discoveries and applications of microwave remote sensing in the future.。
太赫兹电磁波测试流程
太赫兹电磁波测试流程英文回答:Hertzian electromagnetic wave testing, also known as terahertz (THz) wave testing, is a non-destructive testing method that uses electromagnetic waves with frequencies between microwave and infrared to analyze and evaluate materials and structures. It has been widely used in various fields such as security screening, quality control, and medical imaging.The testing process of terahertz electromagnetic waves typically involves the following steps:1. Generation of terahertz waves: Terahertz waves can be generated using different techniques, such as photoconductive switches, quantum cascade lasers, or femtosecond lasers. These methods rely on the interaction between electrons and photons to produce terahertz waves.2. Terahertz wave transmission: Once generated, terahertz waves need to be transmitted to the target material or structure for testing. Terahertz waves can penetrate many non-metallic materials, such as plastics, ceramics, and fabrics, but are strongly absorbed by metals and water.3. Interaction with the sample: When terahertz waves interact with the sample, they undergo various phenomena, including reflection, transmission, absorption, and scattering. These interactions provide valuable information about the sample's properties, such as its thickness, composition, and structural defects.4. Detection and analysis: After interacting with the sample, the terahertz waves are detected and analyzed. Different detection techniques can be used, such as time-domain spectroscopy or frequency-domain spectroscopy. These techniques measure the amplitude and phase of the terahertz waves to extract information about the sample.5. Data processing and interpretation: The detectedterahertz wave signals are processed and analyzed to obtain meaningful information about the sample being tested. This may involve comparing the measured signals with reference data or using mathematical algorithms to extract specific features or parameters.6. Evaluation and decision-making: Based on the analyzed data, the sample can be evaluated and decisions can be made regarding its quality, integrity, orsuitability for a particular application. This may involve comparing the measured parameters with predefined thresholds or standards.Terahertz electromagnetic wave testing offers several advantages, such as non-destructive nature, high penetration capability, and sensitivity to material properties. However, it also has limitations, such as limited penetration through metals and water, and the need for specialized equipment and expertise.中文回答:太赫兹电磁波测试,也被称为太赫兹波(THz)测试,是一种利用介于微波和红外之间频率的电磁波来分析和评估材料和结构的非破坏性测试方法。
太赫兹行波管及其通信应用进展
-毫米波太赫兹通*专辑•太赫兹行波管及其通信应用进展蔡军,冯进军(中国电子科技集团公司第十二研究所微波电真空器件国家级重点实验室"匕京100015#摘要:根据真空电子学发展趋势,行波管的工作频率已经逐步进入太赫兹频域。
随着行波管产品在主要大气窗口大功率、高效率、宽频带电磁波放大能力的不断提升,将推动各类先进的短毫米波和太赫兹武器装备走向实际应用,特别是对于体现创新能力的实验室级器件,通过多次拓展,微加工行波管的最高工作频率已经超过1THz$为了满足下一代通信应用大幅提升速率的需求,国外通过多项研究计划对基于高频率行波管的通信领域方面开展了大量研究$近年来,我国高频率行波管的技术水平不断提升,在该应用领域具有重要的潜力$关键词:太赫兹;行波管;大功率;高效率;高速率通信中图分类号:TN124文献标识码:A文章编号:1002-8935(2021)03-0010-09doi:10.16540/11-2485/tn.2021.03.02THz TWT and Its Application Progress in CommunicationCAI Jun,FENG Jin-jun(.National Key Laboratory of Science and Technology on Vacuum Electronics,Beijing Vacuum Electronics Research Institute,Beijing100015,China#Abstract:According to the development trend of vacuum electronics,the operation frequency of traveling wave t u bes(TWTs)has gradually accessed t o t e raher t z spectrum.Among the amplifiers in mainly a t-mospherewindows"TWTshas manyadvan ages"suchashigh power"high e f iciency and wideband-wid h"whichhave moiva ed heapplica ionsin mili aryelec ronicequipmen.Especia l y"innovaivea-chievemen sofmicrofabrica eddeviceshavebeengainedinlabora ories orealizeTWTsopera ingbeyond 1THz.According oemergingrequiremen sforhigh-ra eda acommunica ion"projec sbasedon TWTs havebecomeoneof he mos a rac ive research areas.In China"TWTs have been experiencing remen-dousgrow hinrecen yearsaspo enialkeydevicefor heimpor an applica ion.Keywords:Terahertz,Traveling wave t u be,High power,High efficiency,High-a t e data communication真空电子器件是当代国防装备和国民经济都在使用的核心电子元器件(1)$电子技越年的悠久历史,其中行波管(TWT)是一类重要的电子器件閃。
太赫兹(THz)科学技术和应用
(三)THz 辐射对于很多非极性物质,如电介质 材料及塑料、纸箱、布料等包装材料有很强的穿透 力, 可用来对已经包装的物品进行质检或者用于安 全检查。
(四)大多数极性分子如水分子,对THz辐射 有强烈的吸收。
在THz成像技术中,可以利用对水的强烈吸收特性分辨生 物组织的不同状态,如对人体烧伤部位的损伤程度进行诊断, 还可以进行产品质量控制,如测量食品表面水分含量以确定 其新鲜程度。
Capital Normal University
3. THz在爆炸物检测中的应用
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日本: Tera-photonics
台湾: Tera-photonics
China: NNSFC 新的 THz 项目
THz辐射主要应用领域
生物医学 安全检查 工业无损检测 空间物理和天文学 环境监测 化学分析 军事和通信领域
一、THz 在国家安全、反恐方面的作用
由于 THz 波对衣物、塑料、陶瓷、硅片、纸张 和干木材等一系列物质具有较好的穿透性能;而且 能够根据物质的THz“指纹谱”,对物质进行识别, 所以在毒品、化学生物危险品和武器等的非接触安 全检测、邮件隐藏物的非接触检测等方面受到了反 恐、保安和海关检查等部门的高度重视。
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三. 在医学成像、诊断上的特殊作用
● MR, CT, PET 在医学成像中发挥很大的作用,但有局限性。
● CT, PET 均采用离子化辐射,可能会引起别的疾病; ● MR 和 CT不能对骨头成像; ● PET 有很高的灵敏度但空间分辨率差。
负折射率隐身衣英文版
Ran Duan,1 Elena Semouchkina,2,* and Ravi Pandey1
1Leabharlann Abstract: The geometric optics principles are used to develop a unidirectional transmission cloak for hiding objects with dimensions substantially exceeding the incident radiation wavelengths. Invisibility of both the object and the cloak is achieved without metamaterials, so that significant widths of the cloaking bands are provided. For the preservation of wave phases, the λ-multiple delays of waves passing through the cloak are realized. Suppression of reflection losses is achieved by using half-λ multiple thicknesses of optical elements. Due to periodicity of phase delay and reflection suppression conditions, the cloak demonstrates efficient multiband performance confirmed by full-wave simulations.
微波灰化-电感耦合等离子体发射光谱法测定婴幼儿乳粉中的钙和磷
第 29 卷第 4 期分析测试技术与仪器Volume 29 Number 4 2023年12月ANALYSIS AND TESTING TECHNOLOGY AND INSTRUMENTS Dec. 2023分析测试经验介绍(407 ~ 413)微波灰化-电感耦合等离子体发射光谱法测定婴幼儿乳粉中的钙和磷陈丽梅,张 慧,白国涛,马彩霞,姚思雨,王 婧(呼和浩特海关技术中心,内蒙古呼和浩特 010020)摘要:采用微波灰化-电感耦合等离子体发射光谱法(ICP-OES)测定婴幼儿乳粉中钙、磷元素含量. 采用微波灰化法对婴幼儿乳粉进行前处理,正交试验方法确定微波灰化最佳条件,灰化后产物用2 mL硝酸溶液(体积比为1∶1)溶解后,用ICP-OES对钙、磷元素进行含量检测. 磷加标回收率为86%~104%,钙加标回收率为87%~96%.磷的相对标准偏差为2.5%~7.0%,钙的相对标准偏差为3.9%~10.0%,能够满足日常检测要求. 采用微波灰化法对婴幼儿乳粉中钙、磷元素进行样品前处理,相比微波消解方法,具有用时短、用酸量少、消解效果好、不需要进行赶酸处理等优点. 与干法灰化和湿法消解相比大大减少了样品处理时间. 采用微波灰化与ICP-OES结合对婴幼儿乳粉中的重要指标元素进行检测,在婴幼儿乳粉质量控制中有很好的应用价值.关键词:微波灰化;电感耦合等离子体发射光谱法;婴幼儿乳粉;钙;磷中图分类号:O657. 31 文献标志码:B 文章编号:1006-3757(2023)04-0407-07DOI:10.16495/j.1006-3757.2023.04.010Detemination of Calcium and Phosphorus in Infant Formula by Microwave Ashing- Inductive Coupled Plasma Emission SpectrometryCHEN Limei, ZHANG Hui, BAI Guotao, MA Caixia, YAO Siyu, WANG Jing(Technology Center of Hohhot Custom, Hohhot 010020, China)Abstract:The microwave ashing-inductive coupled plasma emission spectrometry (ICP-OES ) was used to determine the content of calcium and phosphorus in infant formula. The method of microwave ashing was used to pretreatment of the infant formula. The optimization conditions were determined by orthogonal test. After the microwave ashing, the ashes were dissolved with 2 mL nitric acid solution (volume ratio was 1∶1). The ICP-OES was used to determine the content of calcium and phosphorus. The recoveries of phosphorus and calcium were 86%~104% and 87%~96%, respectively. The relative standard deviation of phosphorus and calcium were 2.5%~7.0% and 3.9%~10.0%, respectively, which could meet the detection requirements. Compared with the method of microwave digestion, microwave ashing has the advantages of shorter time, less acid, better digestion effect and no need to drive acid treatment for calcium and phosphorus in infant formula. Compared with wet digestion and dry ashing, the sample processing time was greatly reduced. The detection of important index elements in infant formula by microwave ashing combined with ICP-OES has a good application value in the quality control of infant formula.Key words:microwave ashing;ICP-OES;infant formula;calcium;phosphorus收稿日期:2023−10−09; 修订日期:2023−12−12.基金项目:海关总署科研项目(批准号:2021HK186)[The Research Project of General Administration of Customs (2021HK186)]作者简介:陈丽梅(1981−),女,高级工程师,主要从事食品中元素检测工作,E-mail:******************.微波灰化技术是一种创新的样品前处理方法,利用抗热的密闭腔体及微波技术来加热,使得灰化速度提高,减少了能量损耗,增加了样品的处理量,工作环境清洁,使用安全. 不同于湿法酸消解,微波灰化的优点是处理过程比较简单,实验室日常工作非常通用,多用于过程及质量控制. 在石油工业、制药业、食品工业、塑料制品制造业、污染物治理等领域都有着广泛的应用. 微波灰化的原理是微波系统发射均匀的微波,穿透高温泡沫陶瓷护体,内置的耐高温泡沫瓷体内的碳化硅板将微波能量转化为热能,热量直接辐射到样品内,样品被均匀加热.微波的使用大大增加了加热效率,相较于传统马弗炉,加热速度大幅提高. 同时,微波灰化消解用酸量也非常小,既节约了酸的使用量,又减少了赶酸过程对环境的污染. 微波灰化消解法在元素检测前处理中主要应用于油料油品[1-5]、塑料 [6-7]、傣药[8]、食用菌[9]、小麦淀粉[10-11]、电泳材料[12]等样品.钙、磷都是人体必须的营养元素. 在人体吸收代谢过程中,钙和磷会相互影响. 根据GB 10765—2021《食品安全国家标准婴儿配方食品》[13]和GB 10767—2021《食品安全国家标准幼儿配方食品》[14]要求,钙磷元素比值范围分别为1∶1~2∶1和1.2∶1~2∶1,如果婴幼儿乳粉中钙磷比例失衡,婴幼儿对钙的有效吸收就会降低,造成膳食中钙营养元素的相对缺乏,影响骨骼和牙齿的发育,因此对婴幼儿乳粉中钙、磷元素进行检测十分必要.目前婴幼儿乳粉前处理方法主要有微波消解[13]、干法灰化[14]、高压罐消解[15]和湿法消解[16]. 国内未见微波灰化法在乳粉前处理中的应用研究. 由于乳粉基质比较复杂,添加物质较多,用传统的前处理方法对乳粉进行消解,有消解时间长、使用酸量大等不足. 本文以微波灰化为前处理方法,结合电感耦合等离子体发射光谱仪(ICP-OES)检测婴幼儿乳粉中钙、磷元素的含量,建立一种用时短、用酸量少的测定乳粉中钙、磷元素含量的检测方法.1 试验部分1.1 仪器与试剂电感耦合等离子体发射光谱仪(720型,安捷伦科技,美国),微波灰化仪(CEM,培安科技,美国),电子天平(Sartorius,塞多利斯公司,德国)(感量:0.001 g),瓷坩埚(50 mL). 硝酸(默克,优级纯),钙、磷标准溶液1 000 mg/L(中国计量科学研究院). 试验过程中所使用婴幼儿乳粉均购自超市,样品编号1、2、5样品为婴幼儿1段乳粉,样品编号3、4为纯奶粉,样品编号6为婴幼儿2段乳粉,样品编号7样品为婴幼儿3段乳粉. 试验过程中使用水均为去离子水. 所有使用的器具使用前均经20%硝酸浸泡过夜.1.2 试验方法1.2.1 标准溶液配制分别吸取钙、磷标准溶液1.0、2.0、3.0、4.0、5.0 mL于100.0 mL容量瓶中,使用2%硝酸定容至刻度,所配制溶液质量浓度分别为10、20、30、40、50 mg/L.硝酸溶液(硝酸∶水体积比为1∶1)配制:量取100 mL硝酸加入至100 mL去离子水中,混合均匀.1.2.2 试验方案在瓷坩埚中称量0.500 g乳粉,设定微波灰化程序进行试验,灰化完成后待微波灰化炉温冷却至150 ℃以下取出坩埚,晾至室温,用2.0 mL硝酸溶液(硝酸∶水体积比为1∶1)溶解灰分,将溶液转移至100.0 mL容量瓶中,用水清洗瓷坩埚,将清洗液转移至容量瓶中,用去离子水定容至刻度,混合均匀后进行钙、磷元素含量测定.1.3 ICP-OES仪器条件ICP-OES检测条件:功率1.2 kW,等离子体气气体流量:15.0 L/min,辅助器流量:1.50 L/min,雾化器流量:0.75 L/min,读数时间:1 s,进样时间:15 s,稳定时间:15 s. 各元素检测波长分别为钙317.933 nm、磷213.618 nm.1.4 微波灰化条件优化方案采用正交试验法对微波灰化条件进行优化,选取4因素4水平正交试验表,因素和水平如表1所列.表 1 正交试验的因素和水平Table 1 Factors and levels of orthogonal test因素因素A(灰化温度)/℃因素B(灰化时间)/min因素C(碳化温度)/℃因素D(碳化时间)/min 水平1450152002水平2500302504水平3550603008水平46009035012408分析测试技术与仪器第 29 卷2 结果与讨论2.1 微波灰化参数优化采用正交试验法对微波灰化的各个参数进行优化. 正交试验方案及结果如表2所列,正交试验结果分析如表3所列.从表3可以看出,磷元素4个因素极差从大到小的顺序为:A>C>B>D,钙元素4个因素极差从大到小的顺序为:A>B>C>D,因此灰化温度在整个灰化过程中起到重要的作用,碳化时间因素影响最小.2.1.1 微波灰化温度的优化正交试验因素的极差结果越大,代表该因素在试验条件中影响较大. 从正交试验极差分析结果可以看出,微波灰化温度极差最大,是影响灰化的最主要因素. 将微波灰化温度各个水平对应的k值为纵坐标,灰化温度为横坐标作因素水平图,如图1(a)所示. 从图1(a)可以看出,当灰化温度达到500 ℃时,钙和磷随着微波灰化温度的提高,所得到的含量没有明显的增加. 钙、磷两种元素最佳微波灰化温度虽然有所差别,但是差别不大. 综合以上结果,选择500 ℃作为微波灰化的最优温度.2.1.2 微波碳化温度的优化从表3可以看出,碳化温度是灰化效果的次主要因素. 碳化过程是将待处理的样品置于低温下使表 2 微波灰化正交试验方案及试验结果Table 2 Orthogonal test programs and results ofmicrowave ashing方案编号试验方案试验结果/(mg/kg)灰化温度/℃灰化时间/min碳化温度/℃碳化时间/min磷钙1450152002 2 605 3 514 2500153508 2 489 3 338 35501525012 2 545 3 411 4600153004 2 638 3 574 54503035012 2 199 2 928 6500302004 2 625 3 532 7550303002 2 615 3 504 8600302508 2 617 3 513 9450602504 2 490 3 334 105006030012 2 710 3 645 11550602008 2 542 3 414 12600603502 2 545 3 451 134******** 2 544 3 392 14500902502 2 650 3 565 155******** 2 721 3 664 166009020012 2 636 3 625表 3 灰化参数优化正交试验结果分析Table 3 Results analysis of orthogonal test/(mg/kg)元素 因素A因素B因素C因素D元素 因素A因素B因素C因素D 磷K19 83810 27710 40810 415钙K113 16813 83714 08514 034 K210 4741005610 30210 474K214 08013 47713 82314 104K310 4231028710 50710 192K313 99313 84414 11513 657K410 43610 5519 95410 090K414 16314 24613 38113 609k1 2 459 2 569 2 602 2 604k1 3 292 3 459 3 521 3 509k2 2 618 2 514 2 576 2 619k2 3 520 3 369 3 456 3 526k3 2 606 2 572 2 627 2 548k3 3 498 3 461 3 529 3 414k4 2 609 2 638 2 488 2 522k4 3 541 3 562 3 345 3 402极差159********极差249193184124极差顺序:A>C>B>D极差顺序:A>B>C>D最优水平:A2B4C3D2最优水平:A4B4C3D2注:K1、K2、K3、K4表示任意列上水平1、水平2、水平3、水平4所对应的试验结果之和;k1、k2、k3、k4表示水平1、水平2、水平3、水平4对应试验结果均值第 4 期陈丽梅,等:微波灰化-电感耦合等离子体发射光谱法测定婴幼儿乳粉中的钙和磷409其碳化,减少因温度上升过快而使得样品灰分的挥发. 以微波灰化碳化温度各个水平对应k 值为纵坐标,碳化温度为横坐标作因素水平图,如图1(b )所示.从图1(b )可以看出,过高的碳化温度并不利于微波灰化的结果. 随着碳化温度的提高,样品碳化过程过快,使得元素随着碳化的烟雾挥出,造成了元素含量的损失. 当碳化温度为300 ℃时,钙和磷含量均达到最佳水平. 因此选择最佳的碳化温度为300 ℃.2.1.3 微波灰化时间的优化以微波灰化时间各个水平对应k 值为纵坐标,微波灰化时间为横坐标作因素水平图,如图1(c )所示.从图1(c )中可看到并没有最优的灰化时间点出现,因此对微波灰化时间进行了单点优化,结果如图1(d)所示. 从图1(d) 中可以看出,当灰化时间达到90 min 后,延长灰化时间对于消解并没有明显的改善,综合考虑各元素的灰化时间,选择最优的灰化时间为90 min.2.1.4 碳化时间的优化以碳化时间各个水平对应k 值为纵坐标,碳化时间为横坐标作因素水平图,结果如图2所示. 从图2可以看出,当碳化时间达到4 min 时,钙和磷的含量水平达到最优,因此所选碳化时间为4 min.2.1.5 称样量的优化通过正交试验结果,选择最佳微波灰化条件:微波灰化温度500 ℃,灰化时间90 min ,碳化温度300 ℃,碳化时间4 min. 在最优的条件下对不同称样量(0.2、0.5、1.0、2.0、3.0 g )样品进行前处理,采用ICP-OES 对其含量进行检测,以样品含量为纵坐标,样品称样量为横坐标作图3. 当称样量达到2.0 g 时,婴幼儿乳粉出现了灰化不完全的情况,定容样品中含有黑色沉淀. 从图3也可以看出,当称2 0002 5003 0003 5004 000元素质量分数/(m g /k g )T /℃1 5002 0002 5003 0003 5004 000T /℃元素质量分数/(m g /k g )1 5002 0002 5003 0003 5004 000元素质量分数/(mg /k g )t /min2 0002 5003 0003 5004 0004 5005 000元素质量分数/(m g /k g )t /min图1 (a )灰化温度、(b )碳化温度、(c )微波灰化时间的因素水平图、(d )微波灰化时间的单点优化Fig. 1 Factor level diagrams of (a) microwave ashing temperatures, (b) microwave carbonization temperatures and(c) microwave ashing times, (d) optimization of microwave ashing times1 5002 0002 5003 0003 5004 000元素质量分数/(m g /k g )t /min图2 碳化时间的因素水平图Fig. 2 Factor level diagram of microwave carbonizationtimes410分析测试技术与仪器第 29 卷样量达到2.0 g 时,检测到的样品含量出现下降的趋势,这是由于样品称样量过多时,样品没有被完全灰化,待测元素无法完全转移到溶液中,造成检测含量降低. 因此最佳称样量应小于2.0 g.2.2 各元素仪器方法学考察采用外标法对各元素进行检测,以元素浓度(X )为横坐标,元素在ICP-OES 检测强度(Y )为纵坐标拟合线性方程,得到线性方程和相对标准偏差(RSD ). 各元素检出限取3倍样品空白标准偏差(n =11)计算,定量限取10倍样品空白标准偏差(n =11)计算. 所得结果如表4所列.表 4 线性方程、检出限和定量限Table 4 Linear regression equations, limits of detection and limits of quantitation元素线性方程线性范围/(mg/L )相关系数RSD/%检出限/(mg/L )定量限/(mg/L )钙Y =37 341.809 + 55 064.512X 0~500.9990.860.023 70.079磷Y =602.582 + 1 742.811X0~500.9990.750.022 50.0752.3 加标回收试验在婴幼儿乳粉中添加标准溶液,采用最优灰化条件进行样品处理后采用ICP-OES 进行检测,结果如表5所列. 从表5可以看出,磷元素加标回收率为86%~104%,钙元素加标回收率为87%~96%. 磷和钙元素6次加标回收率的RSD 分别为2.5%~7.0%,3.9%~10.0%. 加标回收率结果能够满足日常检测要求.表 5 加标回收率Table 5 Results of recovery元素背景/(mg/kg)添加质量分数/(mg/kg)测得质量分数/(mg/kg)加标回收率/%RSD/(%,n =6)磷2 582500 3 0911027.01 000 3 623104 4.22 0004 30386 2.5钙4 1771 0005 0478710.02 0006 01792 4.73 0007 057963.92.4 实际样品的检测采用所建立的方法对市场采购的婴幼儿乳粉进行钙、磷元素含量测定,测定结果如表6所列. 从表中可以看出,所检测的样品编号1、2、5号样品钙磷比值分别为1.4、1.6、1.6,符合GB 10765—2021《食品安全国家标准 婴儿配方食品》[13]要求. 样品编号3、4 号样品是纯奶粉和甜奶粉,钙磷比值分别为1.2和1.1. 样品编号6、7号样品比值分别为1.7、1.3,符合GB 10767—2021《食品安全国家标准 幼儿配方食品》[14]要求.2.5 微波灰化与其他消解方法的比较将微波灰化法与其他前处理方法消解体系和所用时间进行比较,结果如表7所列. 微波灰化前处理方法的精密度和回收率能够满足日常检测的需求. 与干法灰化相比,由于微波的使用,大大增加了加热效率,从而使在进行婴幼儿乳粉前处理过程m /g1 5002 0002 5003 0003 5004 0004 500元素质量分数/(m g /k g )图3 样品称样量的选择Fig. 3 Optimization of sample weights第 4 期陈丽梅,等:微波灰化-电感耦合等离子体发射光谱法测定婴幼儿乳粉中的钙和磷411中所需要的灰化时间更短,总体处理时间与微波消解相当. 微波灰化前处理只需要在灰化完成后用少量酸溶解样品,因此用酸量与湿法消解相比更少.说明微波灰化用于婴幼儿乳粉中钙、磷检测的前处理,所用时间少,消解所用到的酸的种类和剂量也很少,减少了酸的使用对于实验环境和实验人员的危害.3 结论采用微波灰化对婴幼儿乳粉中钙、磷元素进行样品前处理,相比微波消解方法,具有用时短、用酸量少、消解效果好、不需要进行赶酸处理等优势. 与干法灰化和湿法消解相比大大减少了样品处理时间. 采用微波灰化与ICP-OES 结合对婴幼儿乳粉中重要的指标元素钙、磷元素进行检测,是一种快速、环保、准确度高的方法,在婴幼儿乳粉质量控制中有很好的应用价值.参考文献:俞晔, 乙小娟, 刘一军. 微波灰化-原子荧光光谱法测定植物油中砷[J ]. 现代科学仪器,2002(6):48-50.[YU Ye, YI Xiaojuan, LIU Yijun. 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Chemical Analysis and Meterage ,2023,32 (1):6-10.][ 12 ]国家卫生健康委员会, 国家市场监督管理总局. 食品安全国家标准 婴儿配方食品: GB 10765—2021[S ]. 北京: 中国标准出版社, 2021.[ 13 ]国家卫生健康委员会, 国家市场监督管理总局. 食品安全国家标准 幼儿配方食品: GB 10767—2021[S ]. 北京: 中国标准出版社, 2021.[ 14 ]马征, 常雅宁. 微波消解-ICP-OES 法同时测定婴幼儿奶粉中的14种无机元素[J ]. 中国乳品工业,2017,45(1):43-46, 60. [MA Zheng, CHANG Yaning. De-termination of 14 trace elements in infant formula milk powder by microwave digestion-ICP-OES [J ]. China Dairy Industry ,2017,45 (1):43-46, 60.][ 15 ]宋龙波, 赵龙刚, 赵延伟, 等. 火焰原子吸收光谱法测定婴幼儿奶粉中铁、锌元素含量[J ]. 安徽农业科学,2012,40(33):16374-16376. [SONG Longbo, ZHAO Longgang, ZHAO Yanwei, et al. Determination of Fe and Zn in infant formula milk power by flame atomic absorption spectrometry [J ]. Journal of Anhui Agricul-tural Sciences ,2012,40 (33):16374-16376.][ 16 ]吴育廉. 高压密封湿法消解-火焰原子吸收光谱法测定婴儿配方奶粉中铁和锌[J ]. 微量元素与健康研究,2011,28(3):49-50. [WU Yulian. Digestion with high pressure airproof pot - Determined of Fe and Zn in Baby formula by using flame atomic absorption spectrometry [J ]. Studies of Trace Elements and Health ,2011,28 (3):49-50.][ 17 ]陈晓, 张晓文, 赵广才. 三种不同前处理方法对标准奶粉中锰含量测定的影响[J ]. 广东微量元素科学,2015,22(11):27-29. [CHEN Xiao, ZHANG Xiao wen, ZHAO Guangcai, et al. The effect of manganese contentdeterminationbythreepretreatmentmethods [J ]. Guangdong Trace Element Science ,2015,22 (11):27-29.][ 18 ]第 4 期陈丽梅,等:微波灰化-电感耦合等离子体发射光谱法测定婴幼儿乳粉中的钙和磷413。
液晶太赫兹光子学研究进展
第 38 卷第 4 期2023 年 4 月Vol.38 No.4Apr. 2023液晶与显示Chinese Journal of Liquid Crystals and Displays液晶太赫兹光子学研究进展王磊1,2,3,吴双悦1,宗顾卫1,金萍1,张绪1,宋瑞琦1,李炳祥1*,胡伟2*,陆延青2*(1.南京邮电大学电子与光学工程学院、柔性电子(未来技术)学院,江苏南京 210023;2.南京大学现代工程与应用科学学院固体微结构物理国家重点实验室,江苏南京 210093;3.东南大学毫米波国家重点实验室,江苏南京 210096)摘要:液晶作为液态和固态之间的中间态,具有液体的流动性和晶体的各向异性,其指向矢灵活可调,从微波到紫外都有广泛应用。
近年来液晶光子学在太赫兹波段展现出巨大应用前景,本文综述了基于液晶的太赫兹源、可调太赫兹器件和太赫兹探测器的研究进展,探讨了未来液晶太赫兹光子学的发展趋势,如新型铁电向列相、液晶拓扑在太赫兹领域的应用,多模式、多参量的太赫兹波按需产生、调制与探测等。
关键词:液晶;太赫兹源;太赫兹器件;太赫兹探测器中图分类号:O734;O753+.2 文献标识码:A doi:10.37188/CJLCD.2022-0370Research progress of liquid crystal terahertz photonicsWANG Lei1,2,3,WU Shuang-yue1,ZONG Gu-wei1,JIN Ping1,ZHANG Xu1,SONG Rui-qi1,LI Bing-xiang1*,HU Wei2*,LU Yan-qing2*(1.College of Electronic and Optical Engineering & College of Flexible Electronics(Future Technology),Nanjing University of Posts and Telecommunications, Nanjing 210023, China;2.National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences,Nanjing University, Nanjing 210093, China;3.State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210096, China)Abstract: Liquid Crystal (LC), as an intermediate state between liquid and solid, has the fluidity of liquid and the anisotropy of crystal,and its director is flexible and tunable.It has a wide range of applications from microwave to ultraviolet. In recent years, LC photonics has shown great application prospects in the terahertz band. This paper reviews the research progress of LC-based terahertz sources, tunable terahertz devices and terahertz detectors,and discusses the future development of LC terahertz photonics such as 文章编号:1007-2780(2023)04-0419-13收稿日期:2022-11-08;修订日期:2022-11-26.基金项目:国家重点研发计划(No.2022YFA1405000);江苏省自然科学基金(No.K20211277);中国博士后基金(No.2019M651768,No.2020T130285);江苏省前沿引领技术基础研究专项(No.BK20212004)Supported by National Key Research and Development Program of China (No.2022YFA1405000); NaturalScience Foundation of Jiangsu Province (No.K20211277);China Postdoctoral Science Foundation (No.2019M651768,No.2020T130285); Frontier Leading Technology Basic Research Project of Jiangsu Prov‑ince (No.BK20212004)*通信联系人,E-mail:bxli@;huwei@;yqlu@第 38 卷液晶与显示ferroelectric nematic phase, liquid crystal topology, as well as multi-mode and multi-parameter on demand terahertz wave generation, modulation and detection.Key words: liquid crystals; terahertz sources; terahertz devices; terahertz detectors1 引言液晶(liquid crystal, LC)态是一种介于各向同性液态和固态(晶体)之间的中间态。
大功率单路和功率合成式100-115GHz肖特基平衡式二倍频器
第40卷第1期2021年2月红外与毫米波学报J.Infrared Millim.Waves Vol.40,No.1 February,2021文章编号:1001-9014(2021)01-0013-06DOI:10.11972/j.issn.1001-9014.2021.01.003 High power single and power-combined100~115GHz Schottky balanceddoublersTIAN Yao-Ling1,2,HUANG Kun1,2,CEN Ji-Na1,2,TANG Chuan-Yun1,Lin Chang-Xing1,2*,ZHANG Jian3*(1.Microsystem and Terahertz Research Center,China Academy of Engineering Physics,Chengdu610200,China;2.Institute of Electronic Engineering,China Academy of Engineering Physics,Mianyang621900,China;3.School of Electronic Science and Engineering,University of Electronic Science and Technology of China,Chengdu611731,China)Abstract:The research on high power110GHz single and power-combined frequency doublers based on discretediodes is presented in this paper.The doubler with a single Schottky diode circuit has a measured peak efficiencyof33%and bandwidth over13.6%.Meanwhile,two different architectures with two single devices adding in-phase have been utilized to realize the power-combined doublers.The combined doubler features four discreteSchottky diodes with twelve junctions altogether soldered on two127μm-thick ALN substrates.Both deviceshave demonstrated output powers more than200mW with a pumping power over800mW and are capable of pro⁃viding more power for higher driven power.Key words:110GHz,balanced doubler,Schottky,power-combinedPACS:85.30.Hi,85.30.Kk,84.30.Vn,07.57.Hm大功率单路和功率合成式100~115GHz肖特基平衡式二倍频器田遥岭1,2,黄昆1,2,岑冀娜1,2,唐川云1,林长星1,2*,张健3*(1.中国工程物理研究院微系统与太赫兹研究中心,四川成都610200;2.中国工程物理研究院电子工程研究所,四川绵阳621900;3.电子科技大学电子科学与工程学院,四川成都611731)摘要:研究了基于肖特基二极管的单路和功率合成式110GHz大功率平衡式二倍频器。
小型化基片集成波导滤波器研究进展
• 36•小型化基片集成波导滤波器研究进展武警工程大学信息工程学院 张怿成 刘方毅 孟志豪综述了基片集成波导滤波器小型化研究现状。
首先介绍了基片集成波导谐振器的基础理论,其次总结了基片集成波导谐振器小型化的实现方法和存在不足,最后对未来的发展趋势进行了展望。
引言:基片集成波导(Substrate Integrated Waveguide,SIW )滤波器是一种新型结构器件,既具备了传统金属波导高品质因数、高功率等优点,又兼容了微带滤波器结构体积小、易集成的特点,在当今频谱环境日益紧张的通信系统中具有很高的研究和应用价值。
小型化基片集成波导滤波器有利于减少射频前端的体积,且便于和天线、功分器等微波器件相集成,是国内外学者研究的热点方向。
本文阐述了SIW 滤波器小型化的相关理论,介绍了其研究现状和发展趋势。
1 基片集成波导基础理论一般结构的SIW 谐振腔由金属层和介质层构成,腔体边缘周期性排列的的金属过孔可以等效为传统金属波导的侧壁,介质层通常选用Rogers RT/duroid 5880等材料,其结构如图1所示:图1 基片集成波导模型2005年,FengXu 在[Xu F,Wu K.Guided-wave and leakage characteristics of substrate integrated waveguide[J].IEEE Trans-actions on Microwave Theory & Techniques,2005,53(1):66-73]中给出了基片集成波导与金属波导的等效关系式:(1)且SIW谐振器的谐振频率可由下式确定:(2)其中m=1,2,3…, p=1,2,3…, ε为相对介电常数, μ为相对磁导率。
2 基片集成波导滤波器小型化方式SIW 滤波器的小型化技术可以分为三个方面:模切割技术、多层折叠技术、加载技术。
2.1 基于模切割技术的SIW小型化2005年,东南大学的洪伟教授在论文[Hong W,Liu B,Wang Y,et al.Half Mode Substrate Integrated Waveguide:A New Guided Wave Structure for Microwave and Millimeter Wave Application[C]//Joint,International Conference on Infra-red Millimeter Waves and,International Conference on Teraherz Electronics,2006.Irmmw-Thz.IEEE,2007:219-219]中提出了将全模SIW 沿中心线进行切割形成HMSIW ,其切口可等效于虚拟磁壁,既保留了前者的波导特性,又缩小了一半体积,其结构和场分布如图2所示。
微波等离子体英语
微波等离子体英语Microwave plasmas are a fascinating phenomenon, occurring when electromagnetic waves energize gas molecules, creating a state of ionization. They are utilized in various scientific and industrial processes, such as semiconductor manufacturing and waste treatment.These plasmas exhibit unique properties, such as high temperature and reactivity, which make them suitable for advanced material processing. The controlled environment of a microwave plasma chamber allows for precise manipulation of materials at the atomic level.One of the key advantages of using microwave plasma isits ability to generate a uniform and stable plasma state. This uniformity is crucial for applications requiring high precision, such as the deposition of thin films in electronic devices.In the field of environmental science, microwave plasma technology is employed for the decomposition of hazardous waste. It offers a clean and efficient method to break down complex organic compounds into simpler, less harmful substances.The study of microwave plasmas is an interdisciplinary endeavor, combining elements of physics, chemistry, and engineering. Researchers are continually exploring new waysto harness the power of plasma for innovative applications.As our understanding of microwave plasmas deepens, so too does the potential for their use in solving some of theworld's most pressing challenges. From energy production to medical treatments, the possibilities are as vast as the plasma itself.In conclusion, microwave plasmas represent a cutting-edge area of scientific research with wide-ranging implications. Their versatility and efficiency make them an invaluable tool in the quest for technological advancement and environmental sustainability.。
光生亳米波倍频技术与传输性能研究
摘要摘要随着固定网络和无线接入网络对带宽需求的急剧增长,光载射频通信(radio-over-fiber,RoF)技术因其在系统容量、带宽和移动性方面的优势受到了越来越广泛的关注。
其中光生毫米波技术是RoF系统的关键技术之一。
本论文主要对多倍频毫米波光学产生技术及其传输性能进行了研究。
论文首先介绍了光生毫米波技术的基本原理及关键技术,然后提出了三种新型基于外调制器产生多倍频毫米波的方案,并对基于毫米波的RoF传输系统进行了研究,具体研究工作如下:1.提出了三种基于外调制的多倍频光生毫米波技术方案。
方案一,基于一个集成的偏振复用双平行马赫曾德尔调制器(PDM-DPMZM)通过合理的设置射频驱动信号、偏振控制器的角度以及调制器的工作点来产生八倍频光学毫米波信号。
该方案不需要任何光或电的滤波器,并且该方案对调制指数没有非常严格的要求;仿真结果显示,当调制指数设置在一个合理的范围(4.29~4.6),可以由一个10GHz的射频驱动信号产生80GHz的毫米波信号,产生的电谱非常纯净,信噪比(SNR)达到了51.3dB;方案二,基于两个并联的偏振调制器(PolM)实现十二倍频光学毫米波信号。
该方案中偏振调制器(PolM)具备高的消光比并且不需要直流偏置,从而避免了直流偏置漂移问题,保证了系统良好的稳定性。
方案三,基于两个级联的双偏振调制器(DPol-MZM),不使用任何光和电的滤波器产生二十四倍频光学毫米波信号。
通过合理的设置射频驱动信号、双偏振调制器(DPol-MZM)的工作点、光信号的偏振方向,产生了正负十二阶光边带。
通过仿真实现了由一个5GHz的射频驱动信号产生120GHz的毫米波信号2.提出了一种基于集成的双偏振调制器(DPol-MZM)产生二倍频微波光子移向器的方案,仿真结果显示,通过简单的调节光的偏振方向,从检偏器输出的毫米波信号就可以实现0-360○相移,并且在相移调节过程中,信号的幅度始终保持不变。
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978-1-4244-7899-6/10/$26.00 ©2010
IEEE
simple capacitor. The applied DC field induces pizoeffect and resonances develop as shown in Fig.3. In other words the device is switched into resonator mode. While switched on, its resonant frequency may be controlled by an applied DC voltage. In contrast to resonators based on polar phase/piezoelectric ferroelectrics (i.e. PZT) this paraelectric phase resonators are free of hysteresis.
Material LiNb03 KNb03, single crystal BaTi03, single crystal BaTi03/MgO-substrate
n
A,l1m
1.55 0.51.3 1.55
r33, pm/V
30 64 350 734
2.2 2.3 2.5 2.16
Fig.3 Experimental performance of a switchable/tunable BST FBAR in the frequency range 1.9 to 2.1 GHz. The BST film is 730
MICROWAVE AND THz APPLICATIONS OF FERROELECTRICS AND MULTIFERROICS
l l2 S. Gevorgian . and A. Vorobiev Department of Microtechnology and Nanoscience And 2 Microwave and High Speed Electronics Center Ericsson AB, Moelndal, Sweden
nm
thick [3]
IL3 Electro-optic effect Due to the extremely large electro-optic coefficient BaTi03 is considered for ultra wideband travelling wave optical modulators [4]. At telecom wavelengths, A, its refractive index is
I
Chalmers University of Technology, 412 96 Gothenburg
spartak.gevorgian@chalmers.se; Spartak.gevorgyan@
I
Introduction
Ferroelectrics in the form of ceramic [i.e. DC decoupling capacitors based on BaTi03(BT)] have rather long history of industrial applications. In polar phase (e.g. LiNb03) they are used in commercial acousto-electric (i.e. surface acoustic wave, piezotransducers) and electro-optic (i.e. travelling wave optical modulators). Although the DC field dependent dielectric properties for applications in agile microwave devices have been considered since 1950s [I], their successful industrialization, especially in the thin film form, has been demonstrated only in the past decade [2]. Currently the commercialization of agile microwave components based on thick/thin film ferroelectric devices is in progress. The talk will focus on agile microwave devices that utilize tunable permittivity of ferroelectrics [mainly in paraelectric phase (x<0.6) BaxSrl_xTi03 (BST)]. A brief introduction of the other functionalities (switching, electro-optic, DC induced piezoelectricity) for microwave device application will also be given. The potential of natural (single phase, e.g. BiFe03) and artificial (layered and columnar ferroelectric/ferromagnetic nano-composites) multiferroic films for agile GHz and THz applications will be reviewed.
IL4 Dielectric and resistive switching. The dielectric switching is reported in high purity single crystal
&(E)
a)
b)
Fig.1 Field dependent permittivity of a ferroelectric (i.e. BT) in paraelectric (a) and ferrcoustic
properties.
Paraelectric phase BST is not a piezoelectric since its crystal has centro-symmetric
II
Ferroelectrics as multifunctional materials
ILl Exploiting tunability of the dielectric permittivity. In this case the main focus of the developments is in
structure. An applied DC field breaks the symmetricity and for a superimposed microwave field it "pretends" to be piezoelectric. For paraelectric BST the relation between the strain and polarization is given as This means that the effective (induced) piezoelectric coefficient is
S=QP2.
d33=ds/dE=2ssoQE,
i.e. it is field
depended. This field induced piezoelectric effect is used in recently introduced novel type of Film Bulk Acoustic Resonators (FBAR). These switchable/tunable FBARs make use of DC bias dependences of the electromechanical coupling coefficients and resonant frequency. Without applied DC the device acts as a
utilizing nonlinearities in paraelectric phase, Fig.1a. In ferroelectric phase the domains cause extra losses and a "butterfly" shaped C-V, Fig.1b, that may require a DC control voltage of a complex form to avoid the ambiguities of the permittivity at a given DC bias voltage (field). A large number of ferroelectric perovskites based on titanates, tantalates, niobates etc. have been considered for tunable microwave applications. Paraelectric phase BST is the most considered and used in lumped element and distributed (2D, 3D) varactors. An example of ultra-wideband tunable delay line based on thin film lumped element BST varactors is shown in Fig.2. Coplanar waveguides with ferroelectric films in the slots and the beam scanning lens antenna may be indicated as examples of the devices using 2D and 3D distributed varactors [2].