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光学发射光谱法测量氩气微空心阴极放电中特性参数

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光谱学与光谱分析 2010年第7期30卷 1952-1955页

作者：夏广庆 nader sadeghi 大连理工大学工业装备结构分析国家重点实验室运载工程与力学学部航空航天学院辽宁大连116024 光谱物理实验室约瑟夫·傅里叶大学&法国国家科学研究中心

针对微空心阴极放电(MHCD)装置,通过在氩气中添加少量氮气,分析氮分子第一正带系N2(B3ΠgA3u+)发射光谱的方法测量了MHCD中的气体温度,通过氩气中混有的少量氢气,分析Hβ谱线Stark加宽得到电子数密度。研究表明,MHCD在极小的体积和很高... 详细信息

针对微空心阴极放电(MHCD)装置,通过在氩气中添加少量氮气,分析氮分子第一正带系N2(B3ΠgA3u+)发射光谱的方法测量了MHCD中的气体温度,通过氩气中混有的少量氢气,分析Hβ谱线Stark加宽得到电子数密度。研究表明,MHCD在极小的体积和很高的功率密度下维持放电,致使发生了明显的气体加热现象,气体温度可高于700 K,并且随着放电室压强和放电电流呈有规律的变化,具有较好的可控性,电子数密度的量级为1014～1015cm-3。通过对不同条件下等离子体特性参数的诊断和分析,得到了其量级和变化规律,对MHCD的广泛研究和应用提供了重要的实验数据和技术支持。

关键词：微空心阴极放电转动温度气体温度电子数密度光学发射光谱

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一种新颖的微空心阴极放电等离子体推力器

固体火箭技术 2008年第6期31卷 565-568页

作者：夏广庆毛根旺 nader sadeghi 西北工业大学航天学院西安710072 光谱物理实验室约瑟夫·傅立叶大学＆法国国家科学研究中心法国格勒诺布尔38041

微小卫星的发展和成功应用迫切需要新型微推力器的研制。微放电技术是等离子体放电中重要的一类,近几十年来成为各国的研究热点。其中,微空心阴极放电(MHCD)是一种新颖的非平衡高气压辉光放电,其优点是可以在高气压下稳定放电,并且只需... 详细信息

微小卫星的发展和成功应用迫切需要新型微推力器的研制。微放电技术是等离子体放电中重要的一类,近几十年来成为各国的研究热点。其中,微空心阴极放电(MHCD)是一种新颖的非平衡高气压辉光放电,其优点是可以在高气压下稳定放电,并且只需要非常低的电压(几百伏特)或者输入功率(百毫瓦数量级)。MHCD建立在2个几百微米厚度的金属平面电极上,材料可以是钼、铝等,由电介质(云母或氧化铝)隔开。"三明治"的布局结构上从一个电极到另一个电极钻有直径为几十微米到几百微米的孔,气体压强可以很高,甚至超过大气压。微空心阴极放电较小的尺寸结构与强烈并可控的气体加热相结合,可以开发应用在新型的电热式微等离子体推进上。由于微空心阴极放电等离子体推力器在微放电等离子体中加热了工质气体,随后通过微喷管喷出产生推力,因此与传统的冷气微推力器相比,可大大提高推力器的比冲和推力。

关键词：微空心阴极放电电推进微推力器纳卫星推进

微空心阴极放电机理及其在电热式推力器中的应用

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宇航学报 2008年第5期29卷 1607-1611页

作者：夏广庆毛根旺 nader sadeghi 西北工业大学燃烧流动和热结构国家级重点实验室西安710072 约瑟夫.傅立叶大学&法国国家科学研究中心光谱物理实验室

近年来,微空心阴极放电(MHCD)技术的发展为研制适用于小卫星的先进新型微推力器提供了可能。MHCD是微放电领域中一种新颖的非平衡高气压辉光放电,其优点是可以在高气压下稳定放电,并且只需要非常低的电压(几百伏特)或者输入功率(百毫瓦... 详细信息

近年来,微空心阴极放电(MHCD)技术的发展为研制适用于小卫星的先进新型微推力器提供了可能。MHCD是微放电领域中一种新颖的非平衡高气压辉光放电,其优点是可以在高气压下稳定放电,并且只需要非常低的电压(几百伏特)或者输入功率(百毫瓦数量级)。本文针对MHCD,实验研究了微放电的电流-电压特性,并利用光学发射光谱的方法测量了微等离子体中电子数密度和中性气体温度。结果表明,在稳定的辉光放电下,MHCD孔内的电子数密度和中性气体温度随着压强和放电电流的增加而增大,电子数密度可达1014cm-3,中性气体温度可达1000K。由此可以推断,微空心阴极放电较小的尺寸结构与强烈并可控的气体加热相结合,完全可以开发应用在新型的电热式等离子体推进上,研制成微空心阴极放电等离子体推力器。由于在微放电等离子体中加热了工质气体,因此其性能可大大高于冷气推进。

关键词：微空心阴极放电(MHCD) 电推进微推力器纳卫星推进发射光谱

Engineering Nano/Microscale Chiral Self‑Assembly in 3D Printed Constructs

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Nano-Micro Letters 2024年第3期16卷 313-332页

作者： Mohsen Esmaeili Ehsan Akbari Kyle George Gelareh Rezvan nader Taheri‑Qazvini Monirosadat Sadati Department of Chemical Engineering University of South CarolinaColumbiaSC 29208USA TA Instruments Waters LLCNew CastleDE 19720USA Biomedical Engineering Program University of South CarolinaColumbiaSC 29208USA

Helical hierarchy found in biomolecules like cellulose,chitin,and collagen underpins the remarkable mechanical strength and vibrant colors observed in living *** study advances the integration of helical/chiral assembly and 3D printing technology,providing precise spatial control over chiral nano/microstructures of rod-shaped colloidal nanoparticles in intricate *** designed reactive chiral inks based on cellulose nanocrystal(CNC)suspensions and acrylamide monomers,enabling the chiral assembly at nano/microscale,beyond the resolution seen in printed *** employed a range of complementary techniques including Orthogonal Superposition rheometry and in situ rheo-optic measurements under steady shear rate *** techniques help us to understand the nature of the nonlinear flow behavior of the chiral inks,and directly probe the flow-induced microstructural dynamics and phase transitions at constant shear rates,as well as their post-flow ***,we analyzed the photo-curing process to identify key parameters affecting gelation kinetics and structural integrity of the printed object within the supporting *** insights into the interplay between the chiral inks self-assembly dynamics,3D printing flow kinematics and photopolymerization kinetics provide a roadmap to direct the out-of-equilibrium arrangement of CNC particles in the 3D printed filaments,ranging from uniform nematic to 3D concentric chiral structures with controlled pitch length,as well as random orientation of chiral *** biomimetic approach can pave the way for the creation of materials with superior mechanical properties or programable photonic responses that arise from 3D nano/microstructure and can be translated into larger scale 3D printed designs.

关键词： Directed chiral self-assembly Cellulose nanocrystals Bioinspired nanocomposite 3D printing Rheology

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微空心阴极放电数值模拟和发射光谱实验研究

微空心阴极放电数值模拟和发射光谱实验研究

Prediction of vertical displacement for a buried pipeline subjected to normal fault using a hybrid FEM-ANN approach

第十四届全国等离子体科学技术会议暨第五届中国电推进技术学术研讨会

作者：夏广庆毛根旺陈茂林 nader sadeghi 大连理工大学航空航天学院西北工业大学航天学院光谱物理实验室约瑟夫·傅立叶大学&法国国家科学研究中心

微空心阴极放电(Microhollow Cathode Discharge,MHCD)是一种新型的可稳定工作在高气压下甚至大气压下的微放电技术。它具有独特的电光学特性:能产生大量紫外光谱或真空紫外辐射、高能电子束,从而能广泛的应用于光源、光探测器、光谱学... 详细信息

微空心阴极放电(Microhollow Cathode Discharge,MHCD)是一种新型的可稳定工作在高气压下甚至大气压下的微放电技术。它具有独特的电光学特性:能产生大量紫外光谱或真空紫外辐射、高能电子束,从而能广泛的应用于光源、光探测器、光谱学、材料加工、等离子体显示、杀菌、等离子体喷射等领域中,将MHCD作为大体积辉光放

关键词：微空心阴极放电(MHCD) 微等离子体发射光谱等离子体推进

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Frontiers of Structural and Civil Engineering 2024年第3期18卷 428-443页

作者： Hedye JALALI Reza YEGANEH KHAKSAR Danial MOHAMMADZADEH S. nader KARBALLAEEZADEH Amir H.GANDOMI Department of Civil Engineering Architecture and UrbanismSadjad University of TechnologyPO Box ***MashhadIran Department of Civil Engineering Faculty of EngineeringEqbal Lahoori Institute of Higher EducationPO Box ***MashhadIran Faculty of Civil Engineering Architectureand ArtScience and Research Branch of Islamic Azad UniversityPO Box ***TehranIran Faculty of Engineering&Information Technology University of Technology SydneyUltimoNSW 2007Australia University Research and Innovation Center(EKIK) Óbuda UniversityBudapest 1034Hungary

Fault movement during earthquakes is a geotechnical phenomenon threatening buried pipelines and with the potential to cause severe damage to critical ***,effective prediction of pipe displacement is crucial for preventive management *** study aims to develop a fast,hybrid model for predicting vertical displacement of pipe networks when they experience *** this study,the complex behavior of soil and a buried pipeline system subjected to a normal fault is analyzed by using an artificial neural network(ANN)to generate predictions the behavior of the soil when different parameters of it are *** this purpose,a finite element model is developed for a pipeline subjected to normal fault *** data bank used for training the ANN includes all the critical soil parameters(cohesion,internal friction angle,Young’s modulus,and faulting).Furthermore,a mathematical formula is presented,based on biases and weights of the ANN *** results show that the maximum error of the presented formula is 2.03%,which makes the proposed technique efficiently predict the vertical displacement of buried pipelines and hence,helps to optimize the upcoming pipeline projects.

关键词： buried pipelines normal Fault finite element method multilayer perceptron neural network formulation

Understanding the Recovery of the Intervertebral Disc:A Comprehensive Review of In Vivo and In Vitro Studies

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Journal of Bionic Engineering 2024年第4期21卷 1919-1948页

作者： Faten Feki Fahmi Zaïri Abderrahman Tamoud Melissa Moulart Rym Taktak nader Haddar Fahed Zaïri Sfax University ENISMaterials Engineering and Environment Laboratory3038SfaxTunisia University of Lille IMT Nord EuropeJUNIAUniversity of ArtoisULR 4515-LGCgELaboratoire de Génie Civil et geo-Environnement59000LilleFrance PrediTwins Lab 59000LilleFrance Japet Medical Device 59000LilleFrance Sfax University ENISLaboratory of Advanced Materials3038SfaxTunisia Ramsay Générale de Santé Hôpital PrivéLe Bois59000LilleFrance

Within the consistent daily rhythm of human life,intervertebral discs endure a variety of complex loads beyond the influences of gravity and muscle forces,leading to significant morphological changes(in terms of volume,area,and height)as well as biomechanical alterations,including an increase in disc stiffness and a decrease in intradiscal ***,the discs demonstrate an ability to regain their original morphological and biomechanical characteristics after a period of nocturnal *** preservation of normal disc function is critically dependent on this recovery phase,which serves to forestall premature disc *** phenomenon of disc recovery has been extensively documented through numerous in vivo studies employing advanced clinical techniques such as Magnetic Resonance Imaging(MRI),stadiometry,and intradiscal pressure ***,the findings from in vitro studies present a more complex picture,with reports varying between full recovery and only partial recuperation of the disc ***,research focusing on degenerated discs in vitro has shed light on the quantifiable impact of degeneration on the disc ability to *** dynamics within the disc are considered a primary factor in recovery,yet the disc intricate multiscale structure and its viscoelastic properties also play key *** elements interact in complex ways to influence the recovery mechanism,particularly in relation to the overall health of the *** objective of this review is to collate,analyze,and critically evaluate the existing body of in vivo and in vitro research on this topic,providing a comprehensive understanding of disc recovery *** understanding offers a blueprint for future advancements in medical treatments and bionic engineering solutions designed to mimic,support,and enhance the natural recovery processes of intervertebral discs.

关键词： Intervertebral disc Recovery In vivo vs.in vitro studies Degeneration Viscoelastic effects Fluid dynamics

On Zero Dynamics and Controllable Cyber-Attacks in Cyber-Physical Systems and Dynamic Coding Schemes as Their Countermeasures

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IEEE/CAA Journal of Automatica Sinica 2024年第11期11卷 2191-2203页

作者： Mahdi Taheri Khashayar Khorasani nader Meskin the Department of Electrical and Computer Engineering Concordia University the Department of Electrical Engineering Qatar University

In this paper, we study stealthy cyber-attacks on actuators of cyber-physical systems(CPS), namely zero dynamics and controllable attacks. In particular, under certain assumptions, we investigate and propose conditions under which one can execute zero dynamics and controllable attacks in the CPS. The above conditions are derived based on the Markov parameters of the CPS and elements of the system observability matrix. Consequently, in addition to outlining the number of required actuators to be attacked, these conditions provide one with the minimum system knowledge needed to perform zero dynamics and controllable cyber-attacks. As a countermeasure against the above stealthy cyber-attacks, we develop a dynamic coding scheme that increases the minimum number of the CPS required actuators to carry out zero dynamics and controllable cyber-attacks to its maximum possible value. It is shown that if at least one secure input channel exists, the proposed dynamic coding scheme can prevent adversaries from executing the zero dynamics and controllable attacks even if they have complete knowledge of the coding system. Finally, two illustrative numerical case studies are provided to demonstrate the effectiveness and capabilities of our derived conditions and proposed methodologies.

关键词： Controllable attacks cyber-physical systems (CPS) dynamic coding zero dynamics attacks stealthy cyber-attacks

Global systematic review and meta-analysis of knowledge, attitudes, and practices towards dengue fever among the general population

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Asian Pacific Journal of Tropical Medicine 2024年第5期17卷 191-207,I0001-I0003页

作者： Abdolreza Sotoodeh Jahromi Mohammad Jokar Arman Abdous nader Sharifi Tahere Abbasi Vahid Rahmanian Zoonoses Research Center Jahrom University of Medical SciencesJahromIran Faculty of Veterinary Medicine Karaj BranchIslamic Azad UniversityKarajIran Department of Public Health Khomein University of Medical SciencesKhomeinIran Research Center for Social Determinants of Health Jahrom University of Medical SciencesJahromIran Department of Public Health Torbat Jam Faculty of Medical SciencesTorbat JamIran

Objective:To determine the global level of knowledge,attitudes,and practices towards dengue fever among the general ***:To complete this systematic review and meta-analysis,a thorough search for pertinent English-language literature was undertaken during the study's extension until October *** search used Google Scholar,Scopus,PubMed/MEDLINE,Science Direct,Web of Science,EMBASE,Springer,and ProQuest.A quality assessment checklist developed using a modified Newcastle-Ottawa Scale for the cross-sectional study was used to evaluate the risk of bias in the included *** variance and Cochran Q statistics were employed in the STATA software version 14 to assess study *** there was heterogeneity,the Dersimonian and Liard random-effects models were ***:59 Studies totaling 87353 participants were included in this *** investigations included 86278 participants in 55 studies on knowledge,20196 in 33 studies on attitudes,and 74881 in 29 studies on *** pooled estimates for sufficient knowledge,positive attitudes,and dengue fever preventive behaviors among the general population were determined as 40.1%(95%CI 33.8%-46.5%),46.8%(95%CI 35.8%-58.9%),and 38.3%(95%CI 28.4%-48.2%),*** exhibits the highest knowledge level at 63.5%,and Africa shows the lowest at 20.3%.Positive attitudes are most prevalent in the Eastern Mediterranean(54.1%)and Southeast Asia(53.6%),contrasting sharply with the Americas,where attitudes are notably lower at 9.05%.Regarding preventive behaviors,the Americas demonstrate a prevalence of 12.1%,Southeast Asia at 28.1%,Western Pacific at 49.6%,Eastern Mediterranean at 44.8%,and Africa at 47.4%.Conclusions:Regional disparities about the knowledge,attitude and preventive bahaviors are evident with Europe exhibiting the highest knowledge level while Africa has the *** findings emphasize the importance of targeted public health interventions tailored to regional

关键词： Break-bone fever Knowledge Attitudes Practices