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THE BESOV AND TRIEBEL-LIZORKIN SPACES WITH HIGH ORDER ON THE LIPSCHITZ CURVES 被引量:1
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作者 D.G.Deng Y.S.Han 《Analysis in Theory and Applications》 1993年第4期89-106,共18页
The Besov spaces B_p^(α,4)(Γ)and Triebel-Lizorkin spaces F_p^(α,4)(Γ)with high order x∈R on a Lipschitz curve Γ are defind,when 1≤p≤∞,1≤q≤∞.To compare to the classical case.a difference characterization of... The Besov spaces B_p^(α,4)(Γ)and Triebel-Lizorkin spaces F_p^(α,4)(Γ)with high order x∈R on a Lipschitz curve Γ are defind,when 1≤p≤∞,1≤q≤∞.To compare to the classical case.a difference characterization of such spaces in the case|x|<1 is given also. 展开更多
关键词 THE BESOV AND TRIEBEL-LIZORKIN spaceS WITH high ORDER ON THE LIPSCHITZ CURVES SHOW
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Making Public Space in High-density Environment: Strategy and Methodology of Landscape Urbanism
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作者 WANG Yi ZHENG Fen 《Journal of Landscape Research》 2016年第3期53-56,59,共5页
High concentration of population and other elements brought by high urbanization has pushed the future construction of urban public spaces to be both "compact" and "ecological". Theory and methodol... High concentration of population and other elements brought by high urbanization has pushed the future construction of urban public spaces to be both "compact" and "ecological". Theory and methodology of landscape urbanism provides a new perspective for the construction of public spaces in high-density urban environment. Based on the concept and basic standpoints of landscape urbanism, this paper elaborated its potential value in spatial connection, functional integration and vitality promotion, and also analyzed practical strategies of landscape urbanism from three perspectives of structure, fold and stage by combining with typical cases, so as to provide references for designing urban public spaces in high-density environment. 展开更多
关键词 Landscape urbanism high density Public space STRATEGY
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Physiological Response of Space Flight Mutation New Strains of Festuca arundinacea to High Temperature Stress and Comprehensive Evaluation
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作者 Li Juan Lei Xia +3 位作者 Zhong Li Wang Xiaoli Yang Chunyan Wu Jiahai 《Animal Husbandry and Feed Science》 CAS 2017年第5期326-333,共8页
[Objective] The paper was to understand the physiological response of space flight mutation new strains of Festuca arundinacea to high temperature stress. [Method] The influence of high temperature stress on eco-physi... [Objective] The paper was to understand the physiological response of space flight mutation new strains of Festuca arundinacea to high temperature stress. [Method] The influence of high temperature stress on eco-physiological characteristics of 11 F. arundinacea materials was studied in a pot experiment.Physiological and biochemical indexes,including soluble protein content,superoxide dismutase( SOD),peroxidase( POD) and catalase( CAT) activities,were measured and analyzed once every 4 d for a total of three times. Subordinate function and grey rational analysis were used to comprehensively evaluate the heat resistance of 11 materials. [Result] The soluble protein content decreased with the extension of heat resistance stress,while SOD,POD and CAT activities showed an upward trend. The high temperature resistance of 11 F. arundinacea materials was evaluated by subordinate function method. The resistance order was SP5-85> SP5-60 > SP5-71 > SP5-42 > SP5-94 > SP5-7 > SP5-88 > F. arundinacea cv Shuicheng > SP5-5 > SP5-89 = F. arundinacea cv Qiancao No. 1. The relational order of various heat resistance indexes and heat resistance obtained by grey rational analysis was SOD > CAT > POD > soluble protein content. [Conclusion]The result provides a theoretical basis for stress physiology and stress breeding of cold season grass in southwest region. 展开更多
关键词 FESTUCA arundinacea high temperature STRESS space FLIGHT MUTATION PHYSIOLOGICAL characteristics COMPREHENSIVE evaluation
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A New High Rate Differential Space-Time-Frequency Modulation for MIMO-OFDM 被引量:2
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作者 Jun Wang Shou-Yin Liu 《Journal of Electronic Science and Technology of China》 2007年第3期193-197,共5页
In this paper, we propose a new differential space-time-frequency (DSTF) modulation for MIMOOFDM system with four transmit-antennas and arbitrary receive-antennas, which can improve the transmission rate since it ca... In this paper, we propose a new differential space-time-frequency (DSTF) modulation for MIMOOFDM system with four transmit-antennas and arbitrary receive-antennas, which can improve the transmission rate since it can adopt high order quadrature amplitude modulation (QAM) modulation. Our proposed DSTF scheme embeds some full diversity full rate (FDFR) quasi-orthogonal space-time codes (QOSTBC) with QAM modulation into the frequency intervals and adopts the differential modulation in both time and frequency domains. The simulation results demonstrate that the proposed DSTF scheme can improve transmission rate greatly. Compared with the conventional differential unitary space-time modulation (DUSTM), it can get better transmission performance in high transmission rate for MIMO-OFDM system. 展开更多
关键词 Differential modulation high transmission rate MIMO- OFDM space-time-frequency.
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Yarn Expo Autumn reaches a record high of exhibitors and exhibition space
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《China Textile》 2016年第8期62-,共1页
As the most influential trade platform for yarn and fiber industry players in Asia,Yarn Expo Autumn is renowned for its comprehensive range of exhibitors.As such,the show keeps gaining in popularity,with the number of... As the most influential trade platform for yarn and fiber industry players in Asia,Yarn Expo Autumn is renowned for its comprehensive range of exhibitors.As such,the show keeps gaining in popularity,with the number of exhibitors increasing from 258 to morethan 270 this year.To date,they come from 12 countries 展开更多
关键词 Yarn Expo Autumn reaches a record high of exhibitors and exhibition space high
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《空间数据与信息传输系统 航天器SpaceFibre总线通信协议》国家标准解读
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作者 牛跃华 许冬彦 周玉霞 《航天标准化》 2024年第2期36-38,共3页
SpaceFibre总线是专门面向新一代智能航天器在轨海量数据可靠传输设计的新型超高速组网互联技术,其提供了优先级、带宽预留和时隙规划等多种服务质量保证机制,支持最高50Gbps的超高链路传输带宽,具备数据检错重传、链路状态机管理、多... SpaceFibre总线是专门面向新一代智能航天器在轨海量数据可靠传输设计的新型超高速组网互联技术,其提供了优先级、带宽预留和时隙规划等多种服务质量保证机制,支持最高50Gbps的超高链路传输带宽,具备数据检错重传、链路状态机管理、多信道冗余与平滑降级等多层级容错机制,在航天器安全关键应用领域具有显著优势。制定GB/T 43670—2024《空间数据与信息传输系统SpaceFibre总线通信协议标准》,对于支持SpaceFibre核心芯片和网络系统研制,保证各类星载高性能处理设备之间高速通信接口一致性和匹配性,实现整星系统快速集成测试和不同航天器之间产品可重用性具有极其重要的意义。 展开更多
关键词 空间数据与信息传输系统 航天器 spaceFibre 超高速 总线 服务质量 容错
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Lotus LearningSpace在高等特殊教育教学领域的应用 被引量:1
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作者 钱小龙 邹霞 《煤炭高等教育》 2007年第6期111-113,共3页
Lotus LearningSpace是Lotus在知识管理策略基础上推出的最新教学解决方案,旨在提供一个可协作、可按计划、辅助指导、分布式的虚拟学习环境。Lotus LearningSpace简体中文版,为国内有关高等特殊教育的研究机构提供了一个很好的参考。... Lotus LearningSpace是Lotus在知识管理策略基础上推出的最新教学解决方案,旨在提供一个可协作、可按计划、辅助指导、分布式的虚拟学习环境。Lotus LearningSpace简体中文版,为国内有关高等特殊教育的研究机构提供了一个很好的参考。斯塔福德郡大学的实验表明,相关软件开发必须要了解各类残疾人群的特点,考虑残疾学生的主要缺陷,开发专门适合残疾学生的、适用领域广泛的虚拟学习系统。 展开更多
关键词 虚拟学习环境 LOTUS Learningspace 特殊教育 高等特殊教育 残疾学生
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Two suggested configurations for the Chinese space telescope 被引量:2
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作者 Ding-Qiang Su Xiang-Qun Cui 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2014年第9期1055-1060,共6页
China will establish a 2-meter space-based astronomical telescope. Its main science goals are performing a sky survey for research about dark matter and dark energy, and high resolution observations. Some experts sugg... China will establish a 2-meter space-based astronomical telescope. Its main science goals are performing a sky survey for research about dark matter and dark energy, and high resolution observations. Some experts suggest that this space telescope should be installed inside the Chinese space station. In accord with this suggestion we put forward our first configuration, i.e., to adopt a coude system for this telescope. This coude system comes from the Chinese 2.16 m telescope's coude system, which includes a relay mirror so that excellent image quality can be obtained. In our second configuration, we suggest that the whole space telescope fly freely as an independent satellite outside the space station. When it needs servicing, for example, changing in- struments, refilling refrigerant or propellant, etc., this space telescope can fly near or even dock with the core space station. Although some space stations have had accom- panying satellites, the one we propose is a space telescope that will be much larger than other accompanying satellites in terms of weight and volume. On the basis of the second configuration, we also put forward the following idea: the space station can be composed of several large independent modules if necessary. 展开更多
关键词 instruments -- space telescope -- space station -- survey -- high angu- lar resolution
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Electrostatic Discharge Effects on the High-voltage Solar Array 被引量:2
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作者 YUAN Qingyun SUN Yongwei CAO Hefei LIU Cunli 《高电压技术》 EI CAS CSCD 北大核心 2013年第10期2392-2397,共6页
A certain number of charges are deposited on the surface of high-voltage solar array because of effects of space plasma,high-energy charged particles,and solar illumination,hence the surface is charged.Phenomena of el... A certain number of charges are deposited on the surface of high-voltage solar array because of effects of space plasma,high-energy charged particles,and solar illumination,hence the surface is charged.Phenomena of electrostatic discharge(ESD) occur on the surface when the deposited charges exceed a threshold amount.In this paper,the mechanism of this ESD is discussed.The ground simulation experiment of the ESD using spacecraft material under surface charging is described,and a novel ESD protecting method for high-voltage solar array,i.e.an active protecting method based on the local strong electric field array is proposed.The results show that the reversal potential gradient field between the cover surface and the substrate materials of high-voltage solar array is a triggering factor for the ESD on the array.The threshold voltage for the ESD occurring on the surface is about 500 V.The charged particles could be deflected using the electric field active protecting method,and hence the ESD on the surface is avoided even when the voltage on the conductor array increases to a certain value.These results pave the way for further developing the protecting measures for high-voltage solar arrays. 展开更多
关键词 静电放电 太阳电池阵 太阳能电池阵列 电效应 高能带电粒子 表面充电 高压 保护方法
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Hypersonic sliding target tracking in near space 被引量:9
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作者 Xiang-yu ZHANG Guo-hong WANG +1 位作者 Zhen-yu SONG Jiao-jiao GU 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2015年第4期370-381,共12页
To improve the tracking accuracy of hypersonic sliding target in near space,the influence of target hypersonic movement on radar detection and tracking is analyzed,and an IMM tracking algorithm is proposed based on ra... To improve the tracking accuracy of hypersonic sliding target in near space,the influence of target hypersonic movement on radar detection and tracking is analyzed,and an IMM tracking algorithm is proposed based on radial velocity compensating and cancellation processing of high dynamic biases under the earth centered earth fixed(ECEF) coordinate.Based on the analysis of effect of target hypersonic movement,a measurement model is constructed to reduce the filter divergence which is caused by the model mismatch.The high dynamic biases due to the target hypersonic movement are approximately compensated through radial velocity estimation to achieve the hypersonic target tracking at low systematic biases in near space.The high dynamic biases are further eliminated by the cancellation processing of different radars,in which the track association problem can be solved when the dynamic biases are low.An IMM algorithm based on constant acceleration(CA),constant turning(CT) and Singer models is used to achieve the hypersonic sliding target tracking in near space.Simulation results show that the target tracking in near space can be achieved more effectively by using the proposed algorithm. 展开更多
关键词 高超声速流动 目标跟踪 空间 滑翔 动态偏差 IMM算法 高超音速 雷达探测
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From Highly Structured E-Infinity Rings and Transfinite Maximally Symmetric Manifolds to the Dark Energy Density of the Cosmos 被引量:2
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作者 Mohamed S. El Naschie 《Advances in Pure Mathematics》 2014年第12期641-648,共8页
Starting from well established results in pure mathematics, mainly transfinite set theory, E-infinity algebra over operads, fuzzy manifolds and fuzzy Lie symmetry groups, we construct an exact Weyl scaling for the hig... Starting from well established results in pure mathematics, mainly transfinite set theory, E-infinity algebra over operads, fuzzy manifolds and fuzzy Lie symmetry groups, we construct an exact Weyl scaling for the highly structured E-infinity rings corresponding to E-infinity theory of high energy physics. The final result is an exact expression for the energy density of the cosmos which agrees with previous analysis as well as accurate cosmological measurements and observations, such as COBE, WMAP and Planck. The paper is partially intended as a vivid demonstration of the power of pure mathematics in physics and cosmology. 展开更多
关键词 highLY STRUCTURED RINGS E-INFINITY Loop spaces high ENERGY Physics Dark ENERGY Einstein Relativity Fractal-Cantorian spacetime Nonlinear Dynamics Quantum Chaos
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3D-SPACE序列联合高分辨率MRI在直肠癌术前分期中的应用研究 被引量:2
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作者 邵建中 郑后珍 +2 位作者 张兴芳 钱金甲 刘福生 《现代医用影像学》 2023年第1期24-28,共5页
目的:分析3D-SPACE序列联合高分辨率MRI应用于直肠癌术前分期诊断的效果。方法:选取2020年2月至2023年2月于我院就诊的80例直肠癌患者纳入研究,2020年2月至2021年8月收治的40例患者采用标准检查方式,纳入对照组;2021年9月至2023年2月收... 目的:分析3D-SPACE序列联合高分辨率MRI应用于直肠癌术前分期诊断的效果。方法:选取2020年2月至2023年2月于我院就诊的80例直肠癌患者纳入研究,2020年2月至2021年8月收治的40例患者采用标准检查方式,纳入对照组;2021年9月至2023年2月收治患者采用3D-SPACE序列检查和高分辨率MRI检查并纳入观察组,以术后病理学结果为金标准,对比3D-SPACE序列联合高分辨率MRI检查方式与常规T2WI检查对直肠癌分期的诊断效能。结果:对照组的T分期误诊率为25.00%,N分期误诊率为37.50%;观察组的T分期误诊率为7.50%,N分期误诊率为15.00%;观察组T_(1-2)、T_(3)分期、N_(0)、N_(1)、N_(2)分期的诊断准确率较对照组更高(P<0.05);两组T4分期准确率皆较高且无明显差异(P>0.05)。结论:3D-SPACE序列联合高分辨率MRI应用于直肠癌术前分期,在对于进展期患者的浸润程度判断更加准确,对于淋巴结转移情况有较为准确的诊断,对于临床进行术前分期诊断有较高应用价值,值得临床广泛应用。 展开更多
关键词 直肠癌 3D-space序列 高分辨率MRI 术前分期 DWI序列
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Effect of Space Charge on the Propagation Path of Air Gap Discharge
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作者 郝丽霞 王伟 +2 位作者 詹花茂 韩筱慧 邓丽红 《Plasma Science and Technology》 SCIE EI CAS CSCD 2011年第6期714-718,共5页
The existence of space charge may be addressed as one of the reasons that could cause shielding failure of transmission lines. In order to study the effect of space charge on discharge propagation path, a new experime... The existence of space charge may be addressed as one of the reasons that could cause shielding failure of transmission lines. In order to study the effect of space charge on discharge propagation path, a new experimental system, including mainly DC high voltage generator, impulse voltage generator as well as rod-plane electrode, has been established. The space charge was generated around the rod by means of pre-applying DC high voltage, and the air gap dis- charge experiments were conducted with and without pre-applying DC high voltage, respectively. Meanwhile, high speed cameras worked simultaneously from the front and lateral side to record the discharge propagation path so as to obtain the curvature. After statistical analysis, it is shown that the curvature increases in the middle and lower portions of the propagation path when the effect of space charge is taken into account. 展开更多
关键词 CURVATURE discharge propagation path high speed cameras space charge
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柔性直流输电系统中高频振荡研究综述
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作者 李奇南 孙宝奎 +3 位作者 孙华东 张晓林 王子莹 陈鑫 《电力自动化设备》 北大核心 2025年第1期156-171,共16页
近年来,国内外多个电压源型柔性直流输电工程中发生了中高频振荡现象,影响系统的安全稳定运行。针对柔性直流输电系统出现的中高频振荡问题,阐述了柔直换流站阻抗模型和状态空间模型的建立方法,交流系统数学模型建立方法。对使用阻抗分... 近年来,国内外多个电压源型柔性直流输电工程中发生了中高频振荡现象,影响系统的安全稳定运行。针对柔性直流输电系统出现的中高频振荡问题,阐述了柔直换流站阻抗模型和状态空间模型的建立方法,交流系统数学模型建立方法。对使用阻抗分析法、特征值法进行系统稳定性分析的原理、方法进行了说明。基于换流器阻抗模型,分析了电压前馈、电流内环、锁相环、环流控制等因素对换流器阻抗特性的影响。归纳总结了现有中高频振荡抑制策略及其对柔性直流输电系统动态性能的影响,介绍了谐波保护方法。对中高频振荡问题的抑制措施研究进行展望,给出了未来研究方向建议。 展开更多
关键词 阻抗模型 状态空间模型 抑制策略 中高频振荡 动态性能 谐波保护 柔性直流输电
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3.0T MRI 3D Space序列对颅脑动脉斑块出血的诊断应用
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作者 于慧芳 刘冰 《医学影像学杂志》 2022年第1期16-20,共5页
目的探讨磁共振可变翻转角的三维快速自旋回波(3D-sampling perfection with application optimized contrast using different flip angle evolutions,3D-SPACE)序列检测大脑中动脉斑块内出血(intraplaque hemorrhage,IPH)的成像情况... 目的探讨磁共振可变翻转角的三维快速自旋回波(3D-sampling perfection with application optimized contrast using different flip angle evolutions,3D-SPACE)序列检测大脑中动脉斑块内出血(intraplaque hemorrhage,IPH)的成像情况及其诊断价值。方法选取我院就诊的脑动脉粥样硬化的患者100例,所有患者均接受常规MRI检查、3D序列亮血时飞法MR血管成像(time-of-flight magnetic resonance angiography,TOFMRA),同时接受3D-SPACE序列检查。根据常规序列(T1WI、T2WI、3D TOF、T1WI-CE)图像综合评估IPH,并根据患者的临床、影像学结果对所有患者进行评估,将患者分为有症状组和无症状组。对比两组患者3D-SPACE序列评估斑块信号的高低情况,同时对比3D-SPACE及常规MRI各序列对IPH的评估效果。结果有症状组72例患者中通过3D-SPACE序列共检测出142个斑块,其中斑块病灶信号强化2级98个(69.1%),仅11个(7.7%)斑块无信号强化;无症状组28例患者中共检测出49个斑块,其中35个斑块(71.5%)表现为无强化或1级强化。有症状组患者中IPH的发生率显著高于无症状组,同时有症状组患者中3D-SPACE序列信号强化程度显著高于无症状组,差异具有统计学意义(P<0.05)。评估191个斑块中共有112个为IPH,结果提示TOF、T1WI、3D-SPACE序列评估IPH具有较高的敏感性、特异性和一致性,其中3D-SPACE显示IPH的一致性最高。结论3.0T MRI 3D-Space序列能够有效的提示MCA粥样斑块的IPH情况,为合并颅内血管脑动脉斑块患者的危险程度评估及治疗提供参考依据,具有较高的诊断和临床价值。 展开更多
关键词 大脑中动脉 斑块内出血 3D space序列 高分辨率磁共振成像
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微型反应堆高速撞击下核临界安全的初步分析 被引量:1
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作者 王立鹏 曹璐 +7 位作者 陈立新 李锐 刘仕倡 李达 张信一 姜夺玉 胡田亮 江新标 《核技术》 EI CAS CSCD 北大核心 2024年第8期138-148,共11页
微型反应堆可作为月球表面动力、航天器动力等用于太空探索,反应堆发射前需要对发射事故的影响进行安全分析。反应堆高空坠落并撞击到混凝土是主要的临界安全分析场景,高速撞击后反应堆可能重返临界。本文以两种简化的反应堆模型高速撞... 微型反应堆可作为月球表面动力、航天器动力等用于太空探索,反应堆发射前需要对发射事故的影响进行安全分析。反应堆高空坠落并撞击到混凝土是主要的临界安全分析场景,高速撞击后反应堆可能重返临界。本文以两种简化的反应堆模型高速撞击场景为例,利用连续介质力学有限元程序ABAQUS与粒子输运蒙特卡罗程序耦合,完成了纯燃料堆芯垂直撞击地面和带径向反射层和屏蔽层圆柱堆30°倾角撞击地面的模拟,预测了两种场景反应堆高速撞击下keff随时间变化的物理特性。结果表明:纯燃料反应堆垂直撞击地面的keff增加最高可达1000×10^(-5),而具有反射层和屏蔽层反应堆30°倾角撞击地面的keff增加最高为200×10^(-5)。均匀密度变化条件下,采用表面非结构网格与内部非结构网格的蒙卡程序的计算结果符合较好,内部非结构网格能够更真实地捕捉材料的非均匀密度变化效应。本文的研究为微型反应堆高速撞击下的临界安全研究奠定了重要基础。 展开更多
关键词 空间堆 高速撞击 临界安全 蒙特卡罗 ABAQUS
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一种高效星载功率调节与配电单元设计与实现 被引量:1
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作者 蔡晓东 杜青 +4 位作者 徐泽锋 张俊亭 杨袆 夏宁 王超 《航天器工程》 CSCD 北大核心 2024年第1期42-48,共7页
文章结合深空探测供配电分系统任务特点,提出功率调节、配电、火工控制等多功能模块轻小型一体化设计的必要性。介绍了国外功率调节与配电单元的研究现状、国产功率调节与配电单元研制的意义,功率调节与配电单元组成及功能设计,并通过... 文章结合深空探测供配电分系统任务特点,提出功率调节、配电、火工控制等多功能模块轻小型一体化设计的必要性。介绍了国外功率调节与配电单元的研究现状、国产功率调节与配电单元研制的意义,功率调节与配电单元组成及功能设计,并通过多母线融合设计、多路放电均流设计、单元集成化设计等关键技术,解决了深空探测器高可靠轻小型化功率调节与配电单元设计难题。在轨飞行结果表明:功率调节与配电单元功能正常,工作可靠,性能优良。功率调节与配电单元的国产化设计实现,可为其它航天器的设计提供参考和借鉴。 展开更多
关键词 深空探测 高功率质量比 功率调节与配电单元
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Methane Adsorption on Montmorillonite, Kaolinite and Illite at High Pressures
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作者 LIU Dong YUAN Peng +4 位作者 LIU Hongmei TAN Daoyong YUAN Weiwei ZHOU Xiang HE Hongping 《矿物学报》 CAS CSCD 北大核心 2013年第S1期54-54,共1页
Shale gas, which is derived from organic matters in shale and stored in shale deposits, is an important unconventional gas resource and attracts attention due to its significant requirement in the hydrocarbon producti... Shale gas, which is derived from organic matters in shale and stored in shale deposits, is an important unconventional gas resource and attracts attention due to its significant requirement in the hydrocarbon production. Methane (CH4) is the dominant component of shale gas, and adsorbed gas is an important reservoir form. Many studies have investigated the adsorption capacities and adsorption mechanisms of CH4 in shale. Organic matters and clay minerals have been proposed to be the two major components for CH4 adsorption. Adsorption of CH4 in organic matters, such as the adsorption capacity and effects of characteristics of the organic matters, has been well investigated. However, studies on CH4 adsorption on clay minerals have mainly focused on evaluating the adsorption capacity, and very little information about the adsorption mechanism has been provided. For example, the adsorption sites and factors influencing CH4 adsorption on clay minerals remain unclear. Three main reasons account for this: (1) the co-existence of organic matters in samples affects the evaluation of CH4 adsorption on clay minerals; (2) the pressures used during adsorption are not representative of actual reservoir pressures; and (3) the clay minerals selected have low swelling capacity and a smaller interlayer distances than a CH4 size, resulting in the misunderstanding of the CH4 adsorption sites. 展开更多
关键词 methane (CH4) adsorption clay MINERALS INTERLAYER space MONTMORILLONITE high pressure
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Rapid Directional Solidification with Ultra-High Temperature Gradient and Cellular Spacing Selection of Cu-Mn Alloy
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作者 SenYANG YunpengSU +2 位作者 WenjinLIU WeidongHUANG YaoheZHOU 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2003年第3期225-228,共4页
The detailed laser surface remelting experiments of Cu-31.4 wt pct Mn and Cu-26.6 wt pct Mn alloys on a 5 kW CO2 laser were carried out to study the effects of processing parameters (scanning velocity, output power of... The detailed laser surface remelting experiments of Cu-31.4 wt pct Mn and Cu-26.6 wt pct Mn alloys on a 5 kW CO2 laser were carried out to study the effects of processing parameters (scanning velocity, output power of laser) on the growth direction of microstructure in the molten pool and cellular spacing selection under the condition of ultra-high temperature gradient and rapid directional solidification. The experimental results show that the growth direction of microstructure is strongly affected by laser processing parameters. The ultra-high temperature gradient directional solidification can be realized on the surface of samples during laser surface remelting by controlling laser processing parameters, the temperature gradient and growth velocity can reach 106 K/m and 24.1 mm/s, respectively, and the solidification microstructure in the center of the molten pool grows along the laser beam scanning direction. There exists a distribution range of cellular spacings under the laser rapid solidification conditions, and the average spacing decreases with increasing of growth rate. The maximum, λmax, minimum, λmin, and average primary spacing, A, as functions of growth rate, Vb, can be given by,λmax=12.54Vb-0.61, λmin=4.47 Vb-0.52, λ=9.09Vb-0.62, respectively. The experimental results are compared with the current Hunt-Lu model for rapid cellular/dendritic growth, and a good agreement is found. 展开更多
关键词 Laser surface remelting Ultra-high temperature gradient Cellular spacing Cu-Mn alloys
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高品质空间规划引领高质量发展:逻辑关联、响应路径与关键维度 被引量:4
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作者 张京祥 胡航军 《中国土地科学》 CSSCI CSCD 北大核心 2024年第1期20-26,44,共8页
研究目的:探索高质量发展目标与空间规划的逻辑关联,明晰空间规划引领高质量发展的响应路径,提出高品质空间规划应当注重的若干关键维度。研究方法:文献梳理法和归纳演绎法。研究结果:(1)阐明高质量发展的政治经济学要义在于提升社会总... 研究目的:探索高质量发展目标与空间规划的逻辑关联,明晰空间规划引领高质量发展的响应路径,提出高品质空间规划应当注重的若干关键维度。研究方法:文献梳理法和归纳演绎法。研究结果:(1)阐明高质量发展的政治经济学要义在于提升社会总生产的使用价值,相应要实现空间使用价值的有效提升与交换价值的合理增长。(2)指出高质量发展对空间规划的需求,以及空间规划在要素配置、空间协同、创新引领、场景营造和政策供给等方面的总体响应路径。(3)提出高品质空间规划尤其要重视若干关键维度,包括尊重科学规律、前瞻战略引领、主动弹性应变、以人为本、价值活力提升等。研究结论:空间规划是统筹发展要素配置与实体空间建设的公共政策,将多维度的高质量发展理念融入空间规划,有利于形成理想主义、理性主义和现实主义紧密融合的高品质国土空间规划体系。 展开更多
关键词 国土空间规划 高质量发展 空间价值 要素配置 政策供给
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