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Endothelin increases the proliferation of rat olfactory mucosa cells 预览
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作者 Bertrand Bryche Audrey Saint-Albin +3 位作者 Claire Le Poupon Schlegel Christine Baly Patrice Congar Nicolas Meunier 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第2期352-360,共9页
The olfactory mucosa holds olfactory sensory neurons directly in contact with an aggressive environment. In order to maintain its integrity, it is one of the few neural zones which are continuously renewed during the ... The olfactory mucosa holds olfactory sensory neurons directly in contact with an aggressive environment. In order to maintain its integrity, it is one of the few neural zones which are continuously renewed during the whole animal life. Among several factors regulating this renewal, endothelin acts as an anti-apoptotic factor in the rat olfactory epithelium. In the present study, we explored whether endothelin could also act as a proliferative factor. Using primary culture of the olfactory mucosa, we found that an early treatment with endothelin increased its growth. Consistently, a treatment with a mixture of BQ123 and BQ788(endothelin receptor antagonists) decreased the primary culture growth without affecting the cellular death level. We then used combined approaches of calcium imaging, reverse transcriptase-quantitative polymerase chain reaction and protein level measurements to show that endothelin was locally synthetized by the primary culture until it reached confluency. Furthermore, in vivo intranasal instillation of endothelin receptor antagonists led to a decrease of olfactory mucosa cell expressing proliferating cell nuclear antigen(PCNA), a marker of proliferation. Only short-term treatment reduced the PCNA level in the olfactory mucosa cells. When the treatment was prolonged, the PCNA level was not statistically affected but the expression level of endothelin was increased. Overall, our results show that endothelin plays a proliferative role in the olfactory mucosa and that its level is dynamically regulated. This study was approved by the Comité d’éthique en expérimentation animale COMETHEA(COMETHEA C2 EA-45;protocol approval #12-058) on November 28, 2012. 展开更多
关键词 AUTOCRINE factor cell CULTURE cellular dynamics ENDOTHELIN OLFACTION OLFACTORY basal CELLS OLFACTORY epithelium OLFACTORY mucosa primary CULTURE
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直线前进变换为侧向跨步切入动作时的下肢生物力学变化 预览
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作者 李尚华 王海燕 《中国组织工程研究》 CAS 北大核心 2020年第8期1260-1266,共7页
背景:侧向跨步切入动作是运动领域最常见的进攻技术,这显著增加了运动员膝关节受伤的风险,但目前相关侧向跨步动作的生物力学表现策略及下肢关节负荷特征并不十分清楚。目的:选择大学女子甲组篮球、足球运动员进行侧向跨步切入下肢动作... 背景:侧向跨步切入动作是运动领域最常见的进攻技术,这显著增加了运动员膝关节受伤的风险,但目前相关侧向跨步动作的生物力学表现策略及下肢关节负荷特征并不十分清楚。目的:选择大学女子甲组篮球、足球运动员进行侧向跨步切入下肢动作策略,进行生物力学测试,并分析下肢关节的运动学及动力学参数,从而为运动员及教练员预防下肢伤害,尤其是膝关节十字韧带损伤提供重要参考。方法:选择某高校女子甲组足球及篮球各12名运动员作为研究对象,利用三维测力台及运动图像拍摄系统同步获取其侧向跨步切入动作的相关运动学及动力学参数,并运用SPSS 21.0分析软件对相关数据进行处理分析。该试验方案经天津体育学院伦理委员会批准。结果与结论:①足球运动员有较大的着地瞬间踝关节跖屈角度及髋关节外展角度、最大踝关节外翻角度、膝关节屈曲及内旋角度、膝关节屈曲及内旋角度变化量;②足球运动员有较大的踝关节外旋与髋关节内收力矩峰值,篮球运动员则有较大的踝关节跖屈力矩峰值;③篮球运动员有较小的前后分力制动第一及第二峰值、垂直分力第一峰值及较大的前后分力推蹬力峰值;④结果表明,跨步切入动作过程中,足球运动员习惯于前足着地方式进行急停,进而产生较高的地面反作用力,并增加膝关节屈曲角度进行缓冲,同时有较大的踝关节外翻角度及膝关节内旋角度,而篮球运动员在切入过程中膝关节屈曲角度较少,不利于下肢关节对地面反作用力的缓冲,并进而增加前十字韧带损伤风险。 展开更多
关键词 直线前进 侧向跨步 外翻 力矩 内旋 前十字韧带 运动学 动力学 生物力学
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Phase–amplitude model for doubly fed induction generators 预览
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作者 Hua HUANG Ping JU +3 位作者 Xueping PAN Yuqing JIN Xiaoming YUAN Yuan GAO 《现代电力系统与清洁能源学报(英文)》 CSCD 2019年第2期369-379,共11页
The doubly fed induction generator(DFIG) is major type of wind turbine generator used in grid-connected wind farms. Practical models of DFIG have been built to study the influence of wind power generation on power sys... The doubly fed induction generator(DFIG) is major type of wind turbine generator used in grid-connected wind farms. Practical models of DFIG have been built to study the influence of wind power generation on power system dynamics. However, most existing practical models of the DFIG are based on rectangular coordinates,in which frequency variation is neglected. In this paper, a phase-amplitude(P-A) model is proposed for a DFIG based on phase and amplitude of the internal voltage. The model structure is much like that of the synchronous generator, and the rotor voltage can manipulate both the amplitude and the phase of the internal voltage.Comparisons have been made between the new P-A model of the DFIG and the synchronous generator model,as well as the asynchronous motor model.The contributions of the new P-A model of the DFIG are discussed and it is demonstrated that the proposed model has better ability in describing power system dynamic phenomena such as voltage dynamics and structural dynamics. Simulation results and a field test validate these contributions. 展开更多
关键词 DOUBLY fed induction generator(DFIG) MODEL Internal VOLTAGE VOLTAGE DYNAMICS Frequency DYNAMICS
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Glassy dynamics of water at interface with biomolecules:A Mode Coupling Theory test
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作者 Antonio Iorio Gaia Camisasca Paola Gallo 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第10期82-86,共5页
We study the slow dynamics of hydration water upon cooling in two different biological aqueous solutions,one containing a molecule of lysozyme and another with trehalose molecules.In particular we test if the glassy b... We study the slow dynamics of hydration water upon cooling in two different biological aqueous solutions,one containing a molecule of lysozyme and another with trehalose molecules.In particular we test if the glassy behaviour of these solutions fulfils the predictions of the popular Mode Coupling Theory of glassy dynamics.In particular we test the Time Temperature Superposition Principle and the matching of the exponents of the theory.Our results confirm that this theory is able to describe the dynamical behaviour of supercooled water also in non ideal cases as the ones under investigation in the region of mild supercooling. 展开更多
关键词 GLASSY DYNAMICS AQUEOUS SOLUTIONS biomolecules MOLECULAR DYNAMICS
Time-scale separation and stochasticity conspire to impact phenotypic dynamics in the canonical and inverted Bacillus subtilis core genetic regulation circuits
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作者 Lijie Hao Zhuoqin Yang Marc Turcotte 《中国电气与电子工程前沿:英文版》 CSCD 2019年第1期54-68,共15页
Backgrounds In this work, we study two seemingly unrelated aspects of core genetic nonlinear dynamical control of the competence phenotype in Bacillus subtilis, a common Gram-positive bacterium living in the soil. Met... Backgrounds In this work, we study two seemingly unrelated aspects of core genetic nonlinear dynamical control of the competence phenotype in Bacillus subtilis, a common Gram-positive bacterium living in the soil. Methods: We focus on hitherto unchartered aspects of the dynamics by exploring the effect of time-scale separation between transcription and translation and, as well, the effect of intrinsic molecular stochasticity. We consider these aspects of regulatory control as two possible evolutionary handles. Results: Hence, using theory and computations, we study how the onset of oscillations breaks the excitability-based competence phenotype in two topologically close evolutionary-competing circuits: the canonical "wild-type" regulation circuit selected by Evolution and the corresponding indirect-feedback inverted circuit that failed to be selected by Evolution, as was shown elsewhere, due to dynamical reasons. Conclusions^ Relying on in-silico perturbation of the living state, we show that the canonical core genetic regulation of excitability-based competence is more robust against switching to phenotype-breaking oscillations than the inverted feedback organism. We show how this is due to time-scale separation and stochasticity. 展开更多
关键词 Bacillus SUBTILIS competence gene regulation deterministic DYNAMICS stochastic DYNAMICS
Combining Neutron Scattering, Deuteration Technique, and Molecular Dynamics Simulations to Study Dynamics of Protein and Its Surface Water Molecules
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作者 Li-Rong Zheng Liang Hong 《高分子科学:英文版》 CSCD 2019年第11期1083-1091,共9页
Protein internal dynamics is essential for its function. Exploring the internal dynamics of protein molecules as well as its connection to protein structure and function is a central topic in biophysics. However, the ... Protein internal dynamics is essential for its function. Exploring the internal dynamics of protein molecules as well as its connection to protein structure and function is a central topic in biophysics. However, the atomic motions in protein molecules exhibit a great degree of complexities. These complexities arise from the complex chemical composition and superposition of different types of atomic motions on the similar time scales, and render it challenging to explicitly understand the microscopic mechanism governing protein motions, functions, and their connections. Here, we demonstrate that, by using neutron scattering, molecular dynamics simulation, and deuteration technique, one can address this challenge to a large extent. 展开更多
关键词 NEUTRON scattering DEUTERATION techniques Molecular DYNAMICS simulations Protein HYDRATION water DYNAMICS
Flight dynamics characteristics of canard rotor/wing aircraft in helicopter flight mode
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作者 Honggang GAO Ao HE +2 位作者 Zhenghong GAO Yang NA Yangping DENG 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第7期1577-1587,共11页
The aerodynamic layout of the Canard Rotor/Wing(CRW) aircraft in helicopter flight mode differs significantly from that of conventional helicopters. In order to study the flight dynamics characteristics of CRW aircraf... The aerodynamic layout of the Canard Rotor/Wing(CRW) aircraft in helicopter flight mode differs significantly from that of conventional helicopters. In order to study the flight dynamics characteristics of CRW aircraft in helicopter mode, first, the aerodynamic model of the main rotor system is established based on the blade element theory and wind tunnel test results. The aerodynamic forces and moments of the canard wing, horizontal tail, vertical tail and fuselage are obtained via theoretical analysis and empirical formula. The flight dynamics model of the CRW aircraft in helicopter mode is developed and validated by flight test data. Next, a method of model trimming using an optimization algorithm is proposed. The flight dynamics characteristics of the CRW are investigated by the method of linearized small perturbations via Simulink. The trim results are consistent with the conventional helicopter characteristics, and the results show that with increasing forward flight speed, the canard wing and horizontal tail can provide considerable lift,which reflects the unique characteristics of the CRW aircraft. Finally, mode analysis is implemented for the linearized CRW in helicopter mode. The results demonstrate that the stability of majority modes increases with increasing flight speed. However, one mode that diverges monotonously,and the reason is that the CRW helicopter mode has a large vertical tail compared to the conventional helicopter. The results of the dynamic analysis provide optimization guidance and reference for the overall design of the CRW aircraft in helicopter mode, and the model developed can be used for control system design. 展开更多
关键词 CANARD rotor/wing AIRCRAFT DYNAMICS analysis FLIGHT DYNAMICS HELICOPTER LINEARIZATION Model building
Recent advances in physical understanding and quantitative prediction of impinging-jet dynamics and atomization
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作者 Xiaodong CHEN Vigor YANG 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第1期45-57,共13页
Impinging-jet injectors are widely used in liquid propulsion applications, since their simple configuration provides reliable and efficient atomization. The flowfield involves a series of complicated spatio-temporal e... Impinging-jet injectors are widely used in liquid propulsion applications, since their simple configuration provides reliable and efficient atomization. The flowfield involves a series of complicated spatio-temporal evolutions. Much effort has been directed toward understanding the underlying physics and developing quantitative predictions of impinging-jet atomization. This paper summarizes the recent advances in this direction, including state-of-the-art theoretical, experimental, and numerical studies, along with representative results. Finally, concluding remarks address remaining challenges and highlight modeling capabilities of high-fidelity simulations. 展开更多
关键词 Computational fluid DYNAMICS FLOW instability FLOW visualization Gas/liquid interfacial DYNAMICS Impinging-jet ATOMIZATION Theoretical models Two-phase FLOW
球形锂离子筛的制备及其吸附性能 预览
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作者 柳睿 伍攀羽 +2 位作者 石西昌 陈亚 徐徽 《中国有色金属学报》 EI CAS CSCD 北大核心 2019年第4期828-836,共9页
采用了悬浮聚合造粒法,以聚苯乙烯和Li1.6Mn1.6O4粉体为原料制备球形锂离子筛前驱体,经0.5mol/L的HCl解析脱锂,得到球形锂离子筛。并利用X射线衍射、扫描电子显微镜、原子吸收分光光度计等测试手段对样品的晶体结构、形貌、吸附性能等... 采用了悬浮聚合造粒法,以聚苯乙烯和Li1.6Mn1.6O4粉体为原料制备球形锂离子筛前驱体,经0.5mol/L的HCl解析脱锂,得到球形锂离子筛。并利用X射线衍射、扫描电子显微镜、原子吸收分光光度计等测试手段对样品的晶体结构、形貌、吸附性能等进行表征。吸附解析实验结果表明,球形离子筛前驱体在HCl中处理2h后解析基本完成。球形锂离子筛对Li^+的吸附速率比较快,在含锂溶液中吸附3h基本达到平衡。升高温度有利于离子筛对Li^+的吸附,在pH12.57、温度70℃下,离子筛的平衡吸附量为24mg/g。吸附过程符合Langmuir吸附等温方程和动力学二级模型,是单分子层化学吸附。球形锂离子筛对盐湖卤水中的锂具有良好的吸附和选择性以及良好的循环吸附性能,在卤水中经过10次循环吸附后,吸附量仍有9.2mg/g,Mn的总溶损率只有1.92%。 展开更多
关键词 锂离子筛 Li1.6Mn1.6O4 造粒 吸附 动力学 卤水
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基于数字技术的动态图形设计应用研究 预览 被引量:1
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作者 郝锐 《湖南包装》 2019年第2期27-30,39共5页
平面图形设计在新的媒介环境下越来越多地以动态化的方式应用在各个领域。文章对动态图形的历史发展进行了梳理,分析了数字时代图形设计内容的现状、动态化特征及其应用。越来越多的动态图形出现在视觉屏幕当中,拓展了平面设计的语言,... 平面图形设计在新的媒介环境下越来越多地以动态化的方式应用在各个领域。文章对动态图形的历史发展进行了梳理,分析了数字时代图形设计内容的现状、动态化特征及其应用。越来越多的动态图形出现在视觉屏幕当中,拓展了平面设计的语言,在视觉表达方面发挥着重要的作用。未来动态图形设计将以视觉、体验、互动等多种不同的方式融合在更广阔的领域中,各个行业的跨界融合也将成为图形设计领域的新趋势。 展开更多
关键词 数字时代 动态化 动态图形 视觉形式 数字媒体艺术
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4-PRR冗余并联机构驱动力与能耗优化 预览
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作者 胡小亮 谢志江 +3 位作者 吴小勇 刘飞 卢超 唐小斌 《农业机械学报》 EI CAS CSCD 北大核心 2019年第5期413-419,共7页
为在不同马赫数下的流场中进行风洞试验,需对喷管段的型面进行精确控制,为此设计了一种可以实现姿态调整的平面3自由度4 PRR冗余并联机构,根据机构运动特点,利用封闭矢量法和影响系数法求解该机构运动学逆解。在运动学基础上,利用虚功... 为在不同马赫数下的流场中进行风洞试验,需对喷管段的型面进行精确控制,为此设计了一种可以实现姿态调整的平面3自由度4 PRR冗余并联机构,根据机构运动特点,利用封闭矢量法和影响系数法求解该机构运动学逆解。在运动学基础上,利用虚功原理建立了该机构的逆动力学模型,然后根据冗余并联机构驱动方式不唯一的特点,提出驱动力二范数与最小驱动总功率的优化方法,分别得到驱动力与驱动功率曲线,并与非冗余3 PRR并联机构的驱动力与驱动功率进行对比。结果表明,冗余驱动能够较明显地降低驱动器的瞬时驱动力、瞬时驱动功率和运动周期内驱动器所做功,两种优化方法驱动器做功分别减少了49.2%和50.7%。结合驱动力二范数、最小驱动总功率的优化结果,选取适当的驱动方式可以实现冗余并联机构驱动器瞬时驱动力与瞬时驱动功率的均衡与优化,并降低机构运动过程中的功耗。 展开更多
关键词 冗余并联机构 动力学 优化方法 能耗
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Development of a fully coupled aero-hydro-mooring-elastic tool for floating offshore wind turbines 预览
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作者 Yuanchuan Liu Qing Xiao 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第1期21-33,共13页
A floating offshore wind turbine (FOWT) is a coupled system where a wind turbine with flexible blades interacts with a moored platform in wind and waves.This paper presents a high-fidelity aero-hydro-mooring-elastic a... A floating offshore wind turbine (FOWT) is a coupled system where a wind turbine with flexible blades interacts with a moored platform in wind and waves.This paper presents a high-fidelity aero-hydro-mooring-elastic analysis tool developed for FOWT applications.A fully coupled analysis is carried out for an OC4 semi-submersible FOWT under a combined wind/wave condition.Responses of the FOWT are investigated in terms of platform hydrodynamics,mooring dynamics,wind turbine aerodynamics and blade structural dynamics.Interactions between the FOWT and fluid flow are also analysed by visualising results obtained via the CFD approach.Through this work,the capabilities of the tool developed are demonstrated and impacts of different parts of the system on each other are investigated. 展开更多
关键词 FLOATING offshore wind turbine fluid-structure interaction blade ELASTICITY MOORING dynamics OPENFOAM
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空间高光谱相机调焦机构精度分析与试验
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作者 王凯 徐明林 +2 位作者 解鹏 徐振 陶淑苹 《机械工程学报》 EI CAS CSCD 北大核心 2019年第12期29-36,共8页
针对空间高光谱相机的使用特性及要求,设计一套调焦范围±3 mm的像面移动式调焦机构,对偏离的焦面进行校正,以满足高光谱相机成像质量要求。介绍调焦机构的工作原理,对调焦机构的传动关系、定位精度进行理论分析;建立调焦机构的动... 针对空间高光谱相机的使用特性及要求,设计一套调焦范围±3 mm的像面移动式调焦机构,对偏离的焦面进行校正,以满足高光谱相机成像质量要求。介绍调焦机构的工作原理,对调焦机构的传动关系、定位精度进行理论分析;建立调焦机构的动力学模型,进行有限元分析;详细论述编码器码值与CMOS靶面位移关系测试方法,得到真实可靠的调焦公式;动力学试验表明,调焦机构一阶自然频率为182.7 Hz,可以有效地避免共振现象,加速度响应合理,具有较好的强度、刚度;同时在动力学试验前后,对调焦机构分别进行闭环精度测试,定位精度均优于±6μm,试验结果表明调焦机构具有较好的稳定性,满足±10μm的设计指标要求,验证调焦公式以及闭环控制程序设计的有效性。目前,此套调焦机构已经成功在轨运行,各项指标状态良好,满足高光谱相机的成像质量要求。 展开更多
关键词 高光谱相机 调焦机构 精度分析 CMOS靶面 动力学
Influences of load carriage and physical activity history on tibia bone strain
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作者 Henry Wang Mohammad Kia D.Clark Dickin 《运动与健康科学:英文版》 SCIE 2019年第5期478-485,共8页
Background:Military recruits are often afflicted with stress fractures.The military’s strenuous training programs involving load carriage may contribute to the high incidence of tibia stress fractures in the army.The... Background:Military recruits are often afflicted with stress fractures.The military’s strenuous training programs involving load carriage may contribute to the high incidence of tibia stress fractures in the army.The purpose of this study was to assess the influences of incremented load carriage and history of physical activity on tibia bone strain and strain rate during walking.Methods:Twenty recreational basketball players and 20 recreational runners performed 4 walking tasks while carrying 0 kg,15 kg,25 kg,and35 kg loads,respectively.Tibia bone strain and strain rate were obtained through subject-specific multibody dynamic simulations and finite element analyses.Mixed model repeated-measures analyses of variance were conducted.Results:The mean±SE of the runners’ bone strain(μs)during load carriages(0 kg,15 kg,25 kg,and 35 kg)were 658.11±1.61,804.41±1.96,924.49±2.23,and 1011.15±2.71,respectively,in compression and 458.33±1.45,562.11±1.81,669.82±2.05,and 733.40±2.52,respectively,in tension.For the basketball players,the incremented load carriages resulted in compressive strain of 634.30±1.56,746.87±1.90,842.18±2.16,and 958.24±2.63,respectively,and tensile strain of 440.04±1.41,518.86±1.75,597.63±1.99,and 700.15±2.47,respectively.A dose-response relationship exists between incremented load carriage and bone strain and strain rate.A history of regular basketball activity could result in reduced bone strain and reduced strain rate.Conclusion:Load carriage is a risk factor for tibia stress fracture during basic training.Preventative exercise programs,such as basketball,that involved multidirectional mechanical loading to the tibia bones can be implemented for military recruits before basic training commences. 展开更多
关键词 Modeling Multi-body dynamics STRAIN STRAIN RATE Stress FRACTURE WALKING
Detecting Nonlinear Dynamics Using BDS Test and Surrogate Data in Financial Time Series 预览
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作者 Alex Neri Gutierrez Alexis Rodriguez Carranza Ana Gamarra Carrasco 《数学和系统科学:英文版》 2019年第2期46-53,共8页
Physicists experimentalists use many observations of a phenomenon, which are the unknown equations that describe it, in order to understand the dynamics and obtain information on their future behavior. In this article... Physicists experimentalists use many observations of a phenomenon, which are the unknown equations that describe it, in order to understand the dynamics and obtain information on their future behavior. In this article we study the possibility of reproducing the dynamics of the phenomenon using only a measurement scale. The Whitney immersion theorem ideas are presented and generalization of Sauer for fractal sets to rebuild the asymptotic behavior of the phenomena and to investigate evidence of nonlinear dynamics in the reproduced dynamics using the Brock, Dechert, Scheinkman test (BDS). The applications are made in the financial market which are only known stock prices. 展开更多
关键词 NONLINEAR DYNAMICS surrogate DATA BDS TEST and SERIAL TIMES
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黄河皇甫川流域水沙关系特性及关键驱动因素 预览 被引量:2
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作者 黎铭 张会兰 孟铖铖 《水利水电科技进展》 CSCD 北大核心 2019年第5期27-35,共9页
以黄河中游皇甫川流域为研究区,基于1960—2015年的实测日径流和日悬移质输沙量数据,采用双累积曲线法和水沙关系曲线法两种方法,对研究区洪水悬移质泥沙的环路特性进行探究。结果表明:皇甫川流域多年平均径流量为1.11亿m^3,平均输沙量... 以黄河中游皇甫川流域为研究区,基于1960—2015年的实测日径流和日悬移质输沙量数据,采用双累积曲线法和水沙关系曲线法两种方法,对研究区洪水悬移质泥沙的环路特性进行探究。结果表明:皇甫川流域多年平均径流量为1.11亿m^3,平均输沙量为0.31亿t,均呈显著下降趋势,减少速率分别为0.033 1亿m^3/a和0.0101亿t/a;1979、2003年为水沙系列转折年,表现出明显的阶段特性;多年水沙关系曲线可用幂指数拟合,水沙关系未出现明显偏离;植被恢复和水保工程对流域泥沙减少起到重要作用;典型洪水场次条件下水沙C-Q(Concentration- Discharge)环路表现为顺时针、逆时针、逆“8”字形、正“8”字形和线形5种类型,分别描述了次洪水泥沙输移的不同特征。 展开更多
关键词 皇甫川流域 水沙关系曲线 C-Q环路 悬移质 动力学
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Analytic solutions for generalized PT-symmetric Rabi models
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作者 董元浩 张文静 +1 位作者 刘静 谢小涛 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第11期161-167,共7页
We theoretically investigate the exact solutions for generalized parity–time(PT)-reversal-symmetric Rabi models driven by external fields with monochromatic periodic, linear, and parabolic forms, respectively. The co... We theoretically investigate the exact solutions for generalized parity–time(PT)-reversal-symmetric Rabi models driven by external fields with monochromatic periodic, linear, and parabolic forms, respectively. The corresponding exact solutions are presented in terms of the confluent Heun equations without any approximation. In principle, the analytic solutions derived here are valid in the whole parameter space. Such a kind of study may offer potential coherent control schemes of the PT-symmetric two-level systems. 展开更多
关键词 Rabi model PT symmetry population dynamics
Simultaneous acceleration of two kinds of ion beams in the RISP 预览
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作者 Siwon Jang Eun-San Kim 《核技术:英文版》 SCIE CAS CSCD 2019年第6期70-77,共8页
The Rare Isotope Science Project (RISP) is a research complex consisting of a heavy-ion accelerator, which contains a front-end system, a super-conducting linear accelerator, an isotope separator online (ISOL) system,... The Rare Isotope Science Project (RISP) is a research complex consisting of a heavy-ion accelerator, which contains a front-end system, a super-conducting linear accelerator, an isotope separator online (ISOL) system, and an in-flight system. The original purpose of the post-linear-accelerator (post-linac) section was to accelerate either a stable driver beam derived from an electron cyclotron resonance ion source, or an unstable rare-isotope beam from an ISOL system. The post-linac lattice has now been redesigned using a novel and improved acceleration concept that allows the simultaneous acceleration of both a stable driver beam and a radioisotope beam. To achieve this, the post-linac lattice is set for a mass-to-charge ratio (A/q) that is the average of the two beams. The performance of this simultaneous two-beam acceleration is here assessed using two ion beams: 58Ni^8+ and 132Sn^20+. A beam dynamics simulation was performed using the TRACK and TraceWin codes. The resultant beam dynamics for the new RISP post-linac lattice design are examined. We also estimate the effects of machine errors and their correction on the post-linac lattice. 展开更多
关键词 Linear ACCELERATOR SIMULTANEOUS two-beam ACCELERATION HEAVY-ION ACCELERATOR BEAM dynamics
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纤维混凝土隧道衬砌力学性能研究综述 被引量:1
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作者 崔光耀 孙凌云 +2 位作者 左奎现 王明年 荆鸿飞 《现代隧道技术》 EI CSCD 北大核心 2019年第3期1-7,共7页
混凝土是由细骨料、粗骨料、水泥等材料组成的一种复合材料,在混凝土基体中掺入纤维可在一定程度上改善混凝土的性能。文章主要从静力学和动力学两个方面对目前国内外关于纤维混凝土隧道衬砌力学性能的研究现状展开阐述和分析,在静力学... 混凝土是由细骨料、粗骨料、水泥等材料组成的一种复合材料,在混凝土基体中掺入纤维可在一定程度上改善混凝土的性能。文章主要从静力学和动力学两个方面对目前国内外关于纤维混凝土隧道衬砌力学性能的研究现状展开阐述和分析,在静力学方面主要从纤维掺量、纤维种类、形状、承载力计算方法等方面对其抗压、抗剪以及韧性性能进行了深入的研究和探讨;在动力学方面主要分析研究了纤维混凝土结构的变形破坏机制以及纤维的种类、掺量、尺寸大小等对纤维混凝土的抗震、抗冲击和抗爆三个方面的影响。结果表明,在混凝土中掺入一定量的纤维后,其抗压、抗剪以及韧性性能都得到明显的提高;在混凝土中加入纤维能够阻止混凝土内部裂纹的产生和发展,改善混凝土在动力响应作用下的结构变形;如何充分发挥纤维混凝土的韧性性能以及确保复杂地质条件下纤维混凝土隧道衬砌结构的安全性是今后研究的热点和难点。 展开更多
关键词 纤维混凝土 隧道衬砌 力学性能 静力学 动力学
When joggers meet robots:the past,present,and future of research on humanoid robots 预览
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作者 George H.Z.Liu Michael Z.Q.Chen Yonghua Chen 《生物设计与制造(英文)》 CSCD 2019年第2期108-118,共11页
Spawned by fast-paced progress in new materials and integrate circuit technology,the past two decades have witnessed tremendous development of humanoid robots for both scientific and commercial purposes,e.g.emergency ... Spawned by fast-paced progress in new materials and integrate circuit technology,the past two decades have witnessed tremendous development of humanoid robots for both scientific and commercial purposes,e.g.emergency response and daily life assistant.At the root of this trend are the increasing research interests and cooperation opportunities across different laboratories and countries.The application-driven requirements of high effectiveness and reliability of humanoid robots led intensive research and development in humanoid locomotion and control theories.In spite of the progress in the area,challenges such as unnatural locomotion control,inefficient multi-motion planning,and relatively slow disturbances recovery set further requirements for the next generation of humanoid robots.Therefore,the purpose of this work is to review the current development of highly representative bipedal humanoid robots and discuss the potential to move the ideas and models forward from laboratory settings into the real world.To this end,we also review the current clinical understanding of the walking and running dynamics to make the robot more human-like. 展开更多
关键词 HUMANOID ROBOT Walking dynamics Dynamic control BIO-INSPIRED GAIT ROBOT efficiency Shock absorption
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