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A Small-Divergence-Angle Orbital Angular Momentum Metasurface Antenna

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Research 2019年第1期2019卷 149-156页

作者： Jianchun Xu Ke Bi Ru Zhang Yanan Hao Chuwen Lan klaus D.mcdonald-maier Xiaojun Zhai Zidong Zhang Shanguo Huang State Key Laboratory of Information Photonics and Optical Communications School of ScienceBeijing University of Posts and TelecommunicationsBeijing 100876China Beijing University of Posts and Telecommunications Research Institute Shenzhen 518057China Beijing Key Laboratory of Space-Ground Interconnection and Convergence Beijing University of Posts and TelecommunicationsBeijing 100876China School of Computer Science and Electronic Engineering University of EssexColchester CO43SQUK Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China

Electromagnetic waves carrying an orbital angular momentum (OAM) are of great interest. However, most OAM antennas presentdisadvantages such as a complicated structure, low efficiency, and large divergence angle, which prevents their practicalapplications. So far, there are few papers and research focuses on the problem of the divergence angle. Herein, a metasurfaceantenna is proposed to obtain the OAM beams with a small divergence angle. The circular arrangement and phase gradient wereused to simplify the structure of the metasurface and obtain the small divergence angle, respectively. The proposed metasurfaceantenna presents a high transmission coefficient and effectively decreases the divergence angle of the OAM beam. All thetheoretical analyses and derivation calculations were validated by both simulations and experiments. This compact structurepaves the way to generate OAM beams with a small divergence angle.

关键词： antenna surface divergence

Collective effects for long bunches in dual harmonic RF systems

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Chinese Physics C 2008年第2期32卷 139-145页

作者：安世忠 klaus Bongardt Rudolf maier 唐靖宇张天爵 China Institute of Atomic Energy Beijing 102413 China IKP FZ Juelich 52425 JuelichGermany Institute of High Energy Physics CAS Beijing 100049China

The storage of long bunches for large time intervals needs flattened stationary buckets with a large bucket height. Collective effects from the space charge and resistive impedance are studied by looking at the incoherent particle motion for the matched and mismatched bunches. Increasing the RF amplitude with particle number provides r.m.s wise matching for modest intensities. The incoherent motion of large amplitude particles depends on the details of the RF system. The resulting debunching process is a combination of the too small full RF acceptance together with the mismatch, enhanced by the collective effects. Irregular single particle motion is not associated with the coherent dipole instability. For the stationary phase space distribution of the Hofmann-Pedersen approach and for the dual harmonic RF system, stability limits are presented, which are too low if using realistic input distributions. For single and dual harmonic RF system with d=0.31, the tracking results are shown for intensities, by a factor of 3 above the threshold values. Small resistive impedances lead to coherent oscillations around the equilibrium phase value, as energy loss by resistive impedance is compensated by the energy gain of the RF system.

关键词： resistive impedance incoherent motion halo formation coherent dipole instability

Emittance-dominated long bunches in dual harmonic RF system

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Chinese Physics C 2008年第1期32卷 60-66页

作者：安世忠 klaus Bongardt Rudolf maier 唐靖宇张天爵 China Institute of Atomic Energy IKP FZ Juelich 52425 JuelichGermany Institute of High Energy Physics CAS

The storage of long bunches for long time intervals needs flattened stationary buckets with a large bucket height. The longitudinal motion of the initially mismatched beam has been studied for both the single and dual harmonic RF systems. The RF amplitude is determined to be r.m.s wise matched. The bucket height of the single harmonic system is too small even for shorter bunch with only 20% increased energy spread. The Halo formation and even debunching can be seen after a few synchrotron periods for single particles with large amplitude. In the case of small energy spread for a cooled beam, Coulomb interaction cannot be ignored. The external voltage has to be increased to keep the r.m.s bunch length unchanged. The new voltage ratio R（N） simplifies physics for the emittance-dominated bunches with modest particle number N. For the single harmonic system, substantial amount of debunching occurs without increasing the external voltage, but very little if the RF amplitude is doubled. Results from the ORBIT tracking code are presented for the 1 GeV bunch in the HESR synchrotron, part of the GSI FAIR project.

关键词： bucket height mismatch space charge effect debunching

肝炎及其后果急性与慢性肝病的诊断、治疗和预防第4版 4版(修订扩大版)

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保证智能轮椅平滑通过狭窄通道的路径曲率优化算法

1997年

作者：（德）（迈尔）klaus-Peter maier 郝连杰等译

本书介绍了肝炎的发病原因及后果，收集了大量肝炎病发的种类和冶疗的方法。书中主要介绍了急性肝炎的主治方法，是由肝炎专科主治医师们以多年的治疗经验和临床表现而得的，以针对性、科学性和实用性为求广大患者有个健康地、良好地身... 详细信息

ISBN: (纸本)7117027150

本书介绍了肝炎的发病原因及后果，收集了大量肝炎病发的种类和冶疗的方法。书中主要介绍了急性肝炎的主治方法，是由肝炎专科主治医师们以多年的治疗经验和临床表现而得的，以针对性、科学性和实用性为求广大患者有个健康地、良好地身体状况而努力。

关键词：肝炎学科:防治

来源：汇雅图书（南通市图书馆... 评论

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自动化学报 2016年第12期42卷 1874-1885页

作者：陈灵王森胡豁生麦当劳–麦尔.克劳斯费敏锐上海大学机电工程与自动化学院牛津大学计算机与电子工程学院艾塞克斯大学计算机与电子工程学院

为了使用户更感舒适,智能轮椅应该能在具有复杂几何约束的室内环境下平滑地通过狭窄通道.本文提出一个基于路径曲率优化的算法以确保智能轮椅平滑地通过狭窄过道.考虑到路径平滑度取决于路径曲率及其变化率,在通过传感器数据计算出狭窄... 详细信息

为了使用户更感舒适,智能轮椅应该能在具有复杂几何约束的室内环境下平滑地通过狭窄通道.本文提出一个基于路径曲率优化的算法以确保智能轮椅平滑地通过狭窄过道.考虑到路径平滑度取决于路径曲率及其变化率,在通过传感器数据计算出狭窄通道相对于轮椅的位置后,算法以贝塞尔曲线的曲率及其变化率最小为优化目标,以轮椅过通道时的方向及贝塞尔多边形应为凸多边形作为约束,规划出一条平滑的最优路径,然后控制轮椅实时跟踪这条路径.上述过程动态循环运行,实现了智能轮椅平滑通过狭窄通道.仿真中将本文算法同基于A*的路径规划导航算法进行了对比,结果表明本文提出的基于曲率优化的算法可以实现比A*算法路径曲率更小且更加平滑的过狭窄通道过程,并且即使在没有全局地图和定位信息情况下,算法也能控制轮椅平滑地通过狭窄过道.实验中详细阐述了算法的实现过程,实验结果也证实了算法的有效性.

关键词：智能轮椅曲率优化贝塞尔曲线过通道

Induced Deactivation of Genes Encoding Chlorophyll Biosynthesis Enzymes Disentangles Tetrapyrrole- Mediated Retrograde Signaling

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Molecular Plant 2014年第7期7卷 1211-1227页

作者： Hagen Schlicke Annabel Salinas Hartwig Vivien Firtzlaff Andreas S. Richter , Christine Glasser klaus maier Iris Finkemeier Bernhard Grimm Institute of Biology/Plant Physiology Humboldt University Berlin Philippstr. 13 Building 12 D 10115 Berlin Germany Helmholtz Zentrum Monchen Deutsches Forschungszentrum for Gesundheit und Umwelt (GmbH) Ingolstadter Landstr. 1 85764 Neuherberg Germany Max-Planck-lnstitute for Plant Breeding Research. Plant Proteomics and Mass Spectrometry Group Carl-von-Linne Weg 10 50829 Cologne Germany

In photosynthetic organisms, tetrapyrrole-mediated retrograde signals are proposed to contribute to a bal- anced nuclear gene expression （NGE） in response to metabolic activity in chloroplasts. We followed an experimental short- term approach that allowed the assessment of modified NGE during the first hours of specifically modified enzymatic steps of the Mg branch of tetrapyrrole biosynthesis, when pleiotropic effects of other signals can be avoided. In response to 24-h-induced silencing of CHLH, CHLM, and CHL27 encoding the CHLH subunit of Mg chelatase, the Mg protoporphyrin methyltransferase and Mg protoporphyrin monomethylester cyclase, respectively, deactivated gene expression rapidly led to reduced activity of the corresponding enzymes and altered Mg porphyrin levels. But NGE was not substantially altered. When these three genes were continuously inactivated for up to 4 d, changes of transcript levels of nuclear genes were determined. CHL27 silencing for more than 24h results in necrotic leaf lesions and modulated transcript levels of oxidative stress-responsive and photosynthesis-associated nuclear genes （PhANGs）. The prolonged deactivation of CHLH and CHLM results in slightly elevated transcript levels of PhANGs and tetrapyrrole-associated genes. These time-resolved studies indicate a complex scenario for the contribution of tetrapyrrole biosynthesis on NGE mediated by IO2-induced signaling and feedback-regulated ALA synthesis.

关键词： plastid signal transcription analysis retrograde signal tetrapyrrole metabolism Mg protoporphyrin.

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面向对象的数据库系统宣言

计算机科学 1990年第3期17卷 29-37页

作者： Malcolm Atkinson Francois Bancilhon David Dewitt klaus Dittrich David maier Stanley Zdonik 王宗斌王珊

这篇文章试图定义面向对象的数据库系统。它描述了作为一个合格的面向对象的数据库系统所应具备的主要性质和特征。我们把这些特性分成了三组: ·必备的:被称作面向对象的数据库系统所必须满足的特性。它们是复杂对象,对象标识,封装性,... 详细信息

这篇文章试图定义面向对象的数据库系统。它描述了作为一个合格的面向对象的数据库系统所应具备的主要性质和特征。我们把这些特性分成了三组: ·必备的:被称作面向对象的数据库系统所必须满足的特性。它们是复杂对象,对象标识,封装性,类型或类,继承性,结合滞后联编的复载,可扩充性,计算完备性,持久性,辅存管理,并发性,恢复和即席查询功能。·可选的:为了使系统更完善可添加的而非必备的特性。它们是多重继承性,类型检查和推理,分布,设计事务处理和版本。·开放的:设计人员可以选择的特性。它们是程序设计范例,表示系统,类型系统及一致性。我们的立场是,不祇望上述看法成为一个里程碑,以便为进一步的讨论指明方向。

关键词：面向对象数据库

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HCV感染的自然经过

德国医学 1996年第3期13卷 127-129页

作者： klaus-Peter maier 郝连杰 Department of Medicine City Hospital Esslingen Academic Department University of TübingenGermany 同济医科大学附属同济医院

HCV 感染的自然史可以视为病毒和宿主抵抗力相互作用所形成的不同临床后果。病毒绝大多数病人急性感染后,病毒持续存在于体内。慢性化的原因还不太清楚,免疫压力下,病毒迅速变异可能是最重要的因素。在感染的急性阶段。

关键词：丙型肝炎病毒感染自然过程

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庚型肝炎

德国医学 1997年第1期14卷 8-10页

作者： klaus-Peter maier 郝连杰 Stadtlyische Krankenanstalten Esslingen am NeckarGermany 同济医科大学附属同济医院

庚型肝炎为一种RNA病毒(庚型肝炎病毒,Hepatitis G Virus,HGV)引起的急性病毒性肝炎(非甲-非戊型)。为散发性,并常见于高危人群(毒瘾者、多次输血者),常与其它病毒,特别是丙型肝炎病毒(HCV)和丁型肝炎病毒(HDV)同时存在。其对疾病严重... 详细信息

庚型肝炎为一种RNA病毒(庚型肝炎病毒,Hepatitis G Virus,HGV)引起的急性病毒性肝炎(非甲-非戊型)。为散发性,并常见于高危人群(毒瘾者、多次输血者),常与其它病毒,特别是丙型肝炎病毒(HCV)和丁型肝炎病毒(HDV)同时存在。其对疾病严重性、临床经过以及发展成慢性化等的致病意义尚不清楚。

关键词：庚型肝炎病毒学流行病学临床表现治疗