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Attitude maneuver of liquid-filled spacecraft with a flexible appendage by momentum wheel

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Acta Mechanica Sinica 2012年第2期28卷 543-550页

作者： Dan-Dan Yang Bao-zeng Yue Wen-jun Wu xiao-Juan Song Le-Mei Zhu Department of Mechanics School of Aerospace EngineeringBeijing Institute of Technology100081 BeijingChina

Attitude maneuver of liquid-filled spacecraft with an appendage as a cantilever beam by momentum wheel is studied. The dynamic equations are derived by conserva- tion of angular momentum and force equilibrium principle. A feedback control strategy of the momentum wheel is ap- plied for the attitude maneuver. The residual nutation of the spacecraft in maneuver process changes with some chosen parameters, such as steady state time, locations of the liq- uid container and the appendage, and appendage parame- ters. The results indicate that locations in the second and fourth quadrants of the body-fixed coordinate system and the second quadrant of the wall of the main body are better choices *** the liquid containers and the appendage than other locations if they can be placed randomly. Higher density and thicker cross section are better for lowering the residual nutation if they can be changed. Light appendage can be modeled as a rigid body, which results in a larger residual nutation than a flexible model though. The resid- ual nutation decreases with increasing absolute value of the initial sloshing angular height.

关键词： Liquid-filled spacecraft Appendage Attitude maneuver Momentum wheel Steady state time Residual nutation

A spatially triggered dissipative resource distribution policy for SMT processors

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第8期9卷 1070-1082页

作者： Hong-zhou CHEN Xue-zeng PAN Ling-di PING Kui-jun LU xiao-ping CHEN School of Computer Science and Technology Zhejiang University Hangzhou 310027 China

Programs take on changing behavior at nmtime in a simultaneous multithreading （SMT） environment. How reasonably common resources are distributed among the threads significantly determines the throughput and fairness performance in SMT processors. Existing resource distribution methods either mainly rely on the front-end fetch policy, or make distribution decisions according to the limited information from the pipeline. It is difficult for them to efficiently catch the various resource requirements of the threads. This work presents a spatially triggered dissipative resource distribution （SDRD） policy for SMT processors, its two parts, the self-organization mechanism that is driven by the real-time instructions per cycle （IPC） performance and the introduction of chaos that tries to control the diversity Of trial resource distributions, work together to supply sustaining resource distribution optimization for changing program behavior. Simulation results show that SDRD with fine-grained diversity controlling is more effective than that with a coarse-grained one. And SDRD benefits much from its two well-coordinated parts, providing potential fairness gains as well as good throughput gains. Meanings and settings of important SDRD parameters are also discussed.

关键词： Simultaneous multithreading (SMT) Resource distribution Dynamic optimization Dissipative structures

Equality-constrained minimization of polynomial functions

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Science China Mathematics 2015年第10期58卷 2181-2204页

作者： xiao ShuiJing zeng GuangXing Department of Mathematics Nanchang University

This paper investigates the equality-constrained minimization of polynomial functions. Let R be the field of real numbers, and R[x1,..., xn] the ring of polynomials over R in variables x1,..., xn. For an f ∈ R[x1,..., xn] and a finite subset H of R[x1,..., xn], denote by V(f : H) the set {f( ˉα) | ˉα∈ Rn, and h( ˉα) =0, ? h ∈ H}. We provide an effective algorithm for computing a finite set U of non-zero univariate polynomials such that the infimum inf V(f : H) of V(f : H) is a root of some polynomial in U whenever inf V(f : H) = ±∞.The strategies of this paper are decomposing a finite set of polynomials into triangular chains of polynomials and computing the so-called revised resultants. With the aid of the computer algebraic system Maple, our algorithm has been made into a general program to treat the equality-constrained minimization of polynomials with rational coefficients.

关键词： polynomial function equality constraints equality-constrained minimization constrained infimum Wu’s algorithm triangular decompo

An improved methodology for evaluating energy service demand for China's passenger transport sector

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Advances in Climate Change Research 2022年第2期13卷 290-300页

作者： jun-Ling LIU Meng-Yue LI Yuan zeng Ming-Jian YIN xiao-Xuan ZHANG School of Economics and Management School of Humanities and Social SciencesHarbin Institute of TechnologyShenzhen 518055China Environmental Science and New Energy Technology Engineering Laboratory Tsinghua-Berkeley Shenzhen InstituteShenzhen 518055China

China's energy service demand statistics for the passenger transport sector only cover travel activities for business *** incomplete data have made it very difficult to conduct long-term scenario analysis for this ***,this study develops a methodology by refining and combining vehicle activity and travel behavior *** taking advantage of the two methods,the extent of uncertainty in estimates can be reduced.A detailed description of China's energy service demand in the passenger transport sector for the years 2013,2015,and 2017 are *** show that there is a significant underestimation of total passenger transport turnover in governmental *** reevaluation,the total passenger turnover doubled and increased by 146%,167%,and 187%,resulting in national total passenger turnover of 6783,8031,and 9406 billion passenger kilometers in 2013,2015,and 2017,*** majority of missing statistics are caused by not accounting for non-operational road transport,which is dominated by private *** adjustment,the road sector share in total passenger turnover grew substantially from 30%to 40%to approximately 75%,with the proportion of urban travel continuing to *** found that without complete data on China's passenger turnover,it may result in more than three-fold overestimation for future travel demand,leading to inaccurate projections with much higher energy consumption and CO_(2) *** is therefore very important to have a detailed and precise calculation of energy service demand in the passenger transport *** estimation framework and step-by-step process can also be applied to other developing countries which are confronting similar statistical issues.

关键词： Energy service demand Passenger transport turnover Evaluation method China

The neuroprotective effects of oxygen therapy in Alzheimer’s disease:a narrative review

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Neural Regeneration Research 2023年第1期18卷 57-63页

作者： Cui Yang Qiu Yang Yang Xiang Xian-Rong zeng jun xiao Wei-Dong Le School of Medicine University of Electronic Science and Technology of ChinaChengduSichuan ProvinceChina Institute of Neurology Sichuan Provincial People’s HospitalUniversity of Electronic Science and Technology of ChinaChengduSichuan ProvinceChina Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital ChengduSichuan ProvinceChina Department of Hyperbaric Oxygen Sichuan Provincial People’s HospitalUniversity of Electronic Science and Technology of ChinaChengduSichuan ProvinceChina Sichuan Provincial Center for Mental Health Sichuan Academy of Medical Sciences&Sichuan Provincial People’s HospitalChengduSichuan ProvinceChina

Alzheimer’s disease(AD)is a degenerative neurological disease that primarily affects the *** therapy is the main strategy for AD treatment,but current treatments suffer from poor efficacy and a number of side ***-drug therapy is attracting more attention and may be a better strategy for treatment of *** is one of the important factors that contribute to the pathogenesis of *** cellular processes synergistically promote hypoxia,including aging,hypertension,diabetes,hypoxia/obstructive sleep apnea,obesity,and traumatic brain *** evidence has shown that hypoxia may affect multiple pathological aspects of AD,such as amyloid-beta metabolism,tau phosphorylation,autophagy,neuroinflammation,oxidative stress,endoplasmic reticulum stress,and mitochondrial and synaptic *** targeting hypoxia may delay or mitigate the progression of *** studies have shown that oxygen therapy could improve the risk factors and clinical symptoms of *** evidence also suggests that oxygen therapy may improve many pathological aspects of AD including amyloid-beta metabolism,tau phosphorylation,neuroinflammation,neuronal apoptosis,oxidative stress,neurotrophic factors,mitochondrial function,cerebral blood volume,and protein *** this review,we summarized the effects of oxygen therapy on AD pathogenesis and the mechanisms underlying these *** expect that this review can benefit future clinical applications and therapy strategies on oxygen therapy for AD.

关键词： Alzheimer’s disease amyloid-beta metabolism clinical symptoms hypoxia neuroinflammation neuronal apoptosis oxygen therapy pathogenesis risk factor tau phosphorylation

阿拉善-华北北缘晚古生代-早中生代岩浆作用:对古亚洲洋俯冲-闭合过程的制约

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岩石学报 2025年第1期41卷 66-90页

作者：曾浩宋东方肖文交李普庆中国科学院地质与地球物理研究所岩石圈演化与环境演变全国重点实验室北京100029 中国科学院地球科学研究院北京100029 中国科学院新疆生态与地理研究所干旱区生态安全与可持续发展全国重点实验室乌鲁木齐830011 中国科学院大学地球与行星科学学院北京100049

位于中亚造山带南部的阿拉善-华北北缘地区保存了丰富的晚古生代-早中生代岩浆记录,为理解古亚洲洋从俯冲至闭合的构造演化过程提供了关键信息。本文对位于内蒙古西部的甘其毛都地区的4个侵入体进行了岩相学、地球化学、锆石U-Pb年代学... 详细信息

位于中亚造山带南部的阿拉善-华北北缘地区保存了丰富的晚古生代-早中生代岩浆记录,为理解古亚洲洋从俯冲至闭合的构造演化过程提供了关键信息。本文对位于内蒙古西部的甘其毛都地区的4个侵入体进行了岩相学、地球化学、锆石U-Pb年代学和Lu-Hf同位素分析。锆石U-Pb定年表明这些岩体分别形成于早二叠世(283±3Ma、273±5Ma、272±5Ma)和中三叠世(238±3Ma)。早二叠世岩体以石英闪长岩和闪长玢岩为主,富集轻稀土与大离子亲石元素,亏损高场强元素Nb、Ta等,Hf同位素显著亏损(-4.0~+15.6)。它们可能是由俯冲板片流体交代地幔楔部分熔融形成的基性岩浆经分离结晶演化而成。中三叠世侵入体为花岗闪长岩,轻重稀土元素强烈分异,锆石ε_(Hf)(t)值均为正值(+5.0~+8.5),可能代表了碰撞造山阶段新生下地壳物质部分熔融的产物。在此基础之上,本文系统收集并分析了阿拉善-华北北缘地区晚古生代-早中生代岩浆岩的时空分布规律与地球化学特征,以限定其构造背景与深部动力学过程。结合前人研究成果提出:石炭纪时期,古亚洲洋向南俯冲至阿拉善-华北克拉通之下并不断向北后撤;至早二叠世,俯冲板片转变为前进式俯冲,整体处于挤压环境,发育大规模岩浆活动与弧背前陆盆地;早-中三叠世,古亚洲洋闭合,阿拉善-华北克拉通沿索伦缝合带与北侧的中亚弧增生体系发生碰撞-拼贴。

关键词：阿拉善华北北缘晚古生代-早中生代古亚洲洋俯冲-闭合

Quantitative Biostratigraphic Analysis upon the Upper Cretaceous in Tethyan Himalaya

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Acta Geologica Sinica(English Edition) 2013年第4期87卷 926-935页

作者： LI Guangwei zeng jun State Key Laboratory of Continental Tectonics and Dynamics Institute of Geology Chinese Academy of Geological Sciences School of the Geosciences and Resources China University of Geosciences

Biostratigraphic analysis is an essential element for understanding global tectonics and the evolution of life on Earth. Quantitative analysis of sedimentary sequences provides the precise age constraints on timing of significant events in Earth＇s history. This paper presents results from quantitative stratigraphic analysis of Upper Cretaceous Tethyan Himalayan sequences. This analysis resulted in a new composite stratigraphic section for the Cretaceous strata of Tibet （TIBETKCS）. The eight Upper Cretaceous sections were analyzed in this study and 12 planktonic foraminifera zones were recognized based on available data. Quantitative measurements were made using a Graphic Correlation with Graphcor 3.0 software and correlated to the world standard Cretaceous Composite Section （MIDKCS）. The sections were also examined using Constrained Optimization software by CONOP9. Level Penalty was applied as the rule to measure misfit among automatically correlated sections. The new TIBETKCS correlates well with planktonic foraminifera ages from previous work in southern Tibet. A fitting equation of y=？0.19x＋305 with a correlation coefficient of 0.94 was obtained from this work. The ages of the first and last appearances of 64 planktonic foraminifera can be calculated with this equation with ± 0.3 Ma precision. This level of precision is approximately 10 times higher than age determinations with traditional methods. Two extinction events were resolved within this analysis at ~93.5 Ma and ~85.5 Ma corresponding to the Ocean Anoxic Events at Cenomanian-Turonian and Coniacian-Santonian boundaries respectively.

关键词： quantitative biostratigraphy graphic correlation constrained optimization TethyanHimalayan sequences Upper Cretaceous

Enhanced NTRU cryptosystem eliminating decryption failures

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Journal of Systems Engineering and Electronics 2006年第4期17卷 890-895页

作者： Yao jun zeng Guihua Dept. of Electronic Engineering Shanghai Jiaotong Univ. Shanghai 200030 P.R.China

An enhaned NTRU cryptosystem eliminating decryption failures is proposed without using padding schemes and can resist the oracle model andchosen-ciphertext attacks. Because lattice reduction is the main threat to lattice-based cryptosystems, lattice reductionalgorithms are analyzed to evaluate the security of this scheme. Furthermore, the new scheme remains the advantage of high efficiency of original NTRU.

关键词： NTRU cryptosystem polynomial algebra decryption failure lattice reduction.

Light-driven biohybrid system utilizes N2 for photochemical CO2 reduction

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National Science Review 2023年第7期10卷 159-171页

作者： Jin-Yue zeng xiao-Shuang Wang Xin-Hua Liu Qian-Ru Li jun Feng Xian-Zheng Zhang Key Laboratory of Biomedical Polymers of Ministry of Education and Department of Chemistry Wuhan University Wuhan Research Centre for Infectious Diseases and Cancer Chinese Academy of Medical Sciences

Attempting to couple photochemical CO2reduction with N2fixation is usually difficult,because the reaction conditions for these two processes are typically ***,we report that a light-driven biohybrid system can utilize abundant,atmospheric N2to produce electron donors via biological nitrogen fixation,to achieve effective photochemical *** biohybrid system is constructed by incorporating molecular cobalt-based photocatalysts into N2-fixing *** is found that N2-fixing bacteria can convert N2into reductive organic nitrogen and create a localized anaerobic environment,which allows the incorporated photocatalysts to continuously perform photocatalytic CO2reduction under aerobic ***,the light-driven biohybrid system displays a high formic acid production rate of over 1.41×10-14mol h-1cell-1under visible light irradiation,and the organic nitrogen content undergoes an over-3-fold increase within 48 *** work offers a useful strategy for coupling CO2conversion with N2fixation under mild and environmentally benign conditions.

关键词： biohybrid photocatalysis CO2 reduction nitrogen fixation bacterium