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激光漫反射板防护效果研究

激光技术 2024年第2期48卷 223-228页

作者：张启鹏吴桐徐永杰刘明菊中国人民解放军63893部队洛阳471000

为了科学地评估激光漫反射板在激光角度欺骗干扰过程中的防护效果,采用坐标转换的方法,将导引头接收到的指示激光和干扰激光的能量密度放在同一坐标系进行比较,并计算出制导空域干扰覆盖率,分析了漫反射板和目标的法线方向差异对防护效... 详细信息

为了科学地评估激光漫反射板在激光角度欺骗干扰过程中的防护效果,采用坐标转换的方法,将导引头接收到的指示激光和干扰激光的能量密度放在同一坐标系进行比较,并计算出制导空域干扰覆盖率,分析了漫反射板和目标的法线方向差异对防护效果的影响。结果表明,对于典型立方体型目标,当漫反射板的法线与目标垂直面的法线方位相同、俯仰相差在0°~60°范围时,该垂直面的制导空域干扰覆盖率为100%,仅当漫反射板的法线与目标顶部水平面的法线方向完全相同时,该面的制导空域干扰覆盖才为100%;要实现全面的防护,需要根据激光来袭方向和可能的被照射面,设置多个漫反射板进行针对的防护。此研究方法和结果对于激光漫反射板的合理布设和使用有一定参考价值。

关键词：激光技术角度欺骗干扰干扰覆盖率漫反射板

Boundedness of some multipliers on stratified Lie groups

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Frontiers of Mathematics in China 2015年第1期10卷 137-146页

作者： mingju liu Deming LI Department of Mathematics Beihang University Beijing 100191 China LMIB of the Ministry of Education Beijing 100191 China Department of Mathematics Capital Normal University Beijing 100048 China

Let ￡ be the sub-Laplacian on a stratified Lie group G, and let m be a function defined on [0, ＋∞）. We give the boundedness of the multiplier operators m（￡） on Herz-type Hardy spaces on G.

关键词： Stratified group Herz-type Hardy space multiplier

Constitutive model for methane desorption and diffusion based on pore structure differences between soft and hard coal

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International Journal of Mining Science and Technology 2017年第6期27卷 937-944页

作者： liu Yanwei Wang Dandan Hao Fuchang liu mingju Mitri Hani S. School of Safety Science and Engineering Henan Polytechnic University Jiaozuo 454000 China The Collaborative Innovation Center of Coal Safety Production of Henan Province Jiaozuo 454000 China Department of Mining and Materials Engineering McGill University Montreal H3A0E8 Canada School of Civil Engineering Henan Polytechnic University Jiaozuo 454000 China

This paper aims to improve the accuracy and applicability of gas diffusion mathematical models from coal particles. Firstly, a new constitutive model for gas diffusion from coal particles with tri-disperse pore structure is constructed by considering the difference in characteristics between soft coal and hard *** analytical solution is then derived, that is, the quantitative relationship between gas diffusion rate(Qt/Q_∞) and diffusion time(t), The pore structure parameters of soft coal and hard coal from Juji coal mine are determined. Gas diffusion rules are numerically calculated and investigated by physical simulation methods. Lastly, the applicability of this model is verified. The results show that the homogeneous model only applies to the gas diffusion process of hard coal during the initial 10 min. The calculation results from this model and the physical experimental results of soft coal and hard coal are nearly identical during the initial 30 min.

关键词： Soft and hard coal Gas diffusion Pore structure Constitutive models Physical simulation

Zero thermal expansion in Cs_(2)W_(3)O_(10)

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Chinese Chemical Letters 2024年第7期35卷 538-541页

作者： Juan Guo Mingyuan Fang Qingsong liu Xiao Ren Yongqiang Qiao mingju Chao Erjun Liang Qilong Gao School of Physics&Microelectronics Key Laboratory of Materials Physics of Ministry of Education of ChinaZhengzhou UniversityZhengzhou 450052China

Zero thermal expansion materials are important for the practical applications due to their shape stability as changing *** reported concept of average atomic volume is an available method to hunt new zero thermal expansion ***,according to this concept,a tetragonal tungstate Cs_(2)W_(3)O_(10)with zero expansion has been *** is no structure phase transition as increasing temperature from 150 K to 573 *** coefficient of thermal expansion of axes and volume areαa=0.0074×10^(-6)K^(-1),αc=1.63×10^(-6)K^(-1),andαV=1.60×10^(-6)K^(-1),respectively,in the temperature range of 150~573 *** temperature-and pressure-dependent Raman spectra reveal that the vibrations of WO6octahedra libration modes with positive total anharmonicity and W-O-W bending mode with negative Grüneisen parameter are possibly the origin of zero thermal expansion in Cs_(2)W_(3)O_(10).

关键词： Zero thermal expansion Cesium tungstate Raman spectra Average atomic volume Temperature-dependent X-ray diffraction

Determination of indices and critical values of gas parameters of the first gas outburst in a coal seam of the Xieqiao Mine

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International Journal of Mining Science and Technology 2012年第1期22卷 89-93页

作者： Ou Jianchun liu mingju Zhang Chunru liu Yanwei Wei Jianping School of Safety Engineering Chino University of Mining&TechnologyXuzhou 221008China Science and Engineering Henan Polytechnic UniversityJiaozuo 454003China Xieqiao Mine of Huainan Mining Industry Group Huainan 232001Chino

Based on the important role in mine safety played by parameters of the first gas outburst, we propose a method of combining historic data, theoretical analysis and experimental research for the purpose of critical values of gas parameters of the first gas outburst in a coal seam of the Xieqiao Mine. According to a characteristic analysis and a summary of the rules of coal and gas outbursts in the No.8 coal seam of a Huainan mine, we have investigated their effect on coal and gas outbursts in terms such as ground stress, gas, and coal structure. We have selected gas parameters and determined the critical values of each of the following indices: gas content as 7.7 m 3 /t, tectonic coal as 0.8 m thick, the absolute gas emission as 2 m 3 /min, the rate of change as 0.7 m 3 /min, the gas desorption index of a drilling chip K 1 as 0.26 mL/(g min 1/2 ) and the values of desorption indexes 4h 2 as 200 Pa. From a verification of the production, the results indicate that application of each index and their critical values significantly improve the level of safety in the production process, relieve the burden upon the mine, save much labor and bring clear economic benefits.

关键词：煤与瓦斯突出气体参数谢桥煤矿临界值煤层绝对瓦斯涌出量测定宾夕法尼亚州

Some Classes of Disconnected Antimagic Graphs and Their Joins

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Wuhan University Journal of Natural Sciences 2012年第3期17卷 195-199页

作者： WANG Tao liu mingju LI Deming Department of Foundation North China Institute of Scienceand Technology Sanhe 065201 Hebei China Department of Mathematics Beihang University Beijing100083 China Department of Mathematics Capital Normal UniversityBeijing 100048 China

A labeling of a graph G is a bijection from E（G） to the set {1,2,…,｜E （G）｜ }.A labeling is antimagic if for any distinct vertices x and y,the sum of the labels on edges incident to x is different from the sum of the labels on edges incident to *** say that a graph is antimagic if it has an antimagic *** and Ringel conjectured in 1990 that every graph other than 2 K is *** this paper,we show that the antimagic conjecture is false for the case of disconnected ***,we find some classes of disconnected graphs that are antimagic and some classes of graphs whose complement are disconnected are antimagic.

关键词： antimagic labeling union join path

ROUGH OPERATORS AND COMMUTATORS ON HOMOGENEOUS WEIGHTED HERZ SPACES

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Approximation Theory and Its Applications 2002年第1期18卷 51-57页

作者： Jiang Yinsheng and liu mingju (Xinjiang University , China) Department of Mathematics Xinjiang University Urumqi PR China

The authors establish the baundedness on homogeneous weighted Herz spaces for a large class of rough operators and their commutators with BMO functions. In particular, the Calderon-Zygmund singular integrals and the rough R. Fefferman singular integral operators and the rough Ricci-Stein oscillatory singular integrals and the corresponding commutators are considered.

关键词： BMO Math ROUGH OPERATORS AND COMMUTATORS ON HOMOGENEOUS WEIGHTED HERZ SPACES

德隆水库堆石混凝土重力坝枢纽布置及结构计算

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河南科技 2022年第3期41卷 71-74页

作者：刘明菊遵义市水利水电勘测设计研究院有限责任公司贵州遵义563002

针对德隆水库坝址区地形地质复杂,强岩溶及断层发育,岩体均一性差、抗变形能力不一致等问题。结合地质勘探和当地石料分析情况,综合考虑坝型适宜性、枢纽布置、边坡稳定和承压水影响等因素。优选能充分利用当地石料、基础开挖和坝体填... 详细信息

针对德隆水库坝址区地形地质复杂,强岩溶及断层发育,岩体均一性差、抗变形能力不一致等问题。结合地质勘探和当地石料分析情况,综合考虑坝型适宜性、枢纽布置、边坡稳定和承压水影响等因素。优选能充分利用当地石料、基础开挖和坝体填筑量小、枢纽布置紧凑的重力坝方案。论证分析成果表明,大坝的应力、地基承载力及大坝整体稳定均满足规范要求,枢纽布置和结构体型设计合理,可为类似工程的设计提供技术指导。

关键词：坝型比选堆石混凝土重力坝岩溶裂隙德隆水库

Frequency Regulation of VSC-MTDC System with Offshore Wind Farms

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 275-286页

作者： Haoyu liu Chongru liu North China Electric Power University Beijing 102206China

Frequency regulation of voltage source converter-based multi-terminal high-voltage direct current(VSC-MTDC)system with offshore wind farms enhances the frequency stability by compensating the power for a disturbed AC ***,it is difficult to reasonably allocate frequency-regulation resources due to a lack of coordination mechanisms between wind farms and the MTDC ***,it is difficult for the frequency control of the wind farms to manage changes in wind speed;and the risk of wind-turbine stalls is ***,based on the kinetic energy of wind turbines and the power margin of the converters,the frequency-regulation capability of wind turbines is evaluated,and a dynamic frequency-support scheme considering the real-time frequency-support capability of the wind turbines and system frequency evolution is proposed to improve the frequency-support performance.A power adaptation technique at variable wind speeds is developed;the active power in the frequency-support stage and restoration stage is switched according to the wind speed.A hierarchical zoning frequency-regulation scheme is designed to use the frequency-regulation resources of different links in the MTDC system with wind *** simulation results show that the novel frequency-regulation strategy maintains frequency stability with wind-speed changes and avoids multiple frequency dips.

关键词： Wind generation voltage source converter-based multi-terminal high-voltage direct current(VSC-MTDC) frequency regulation cooperative control adaptive control variable wind speed