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Search Results: 1 - 10 of 91984 matches for " ZHOU Xu-Hua "
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Dual-Band Frequency Selective Surface with Miniaturized Element in Low Frequencies
Yuan Yang;Xu-Hua Wang;Hang Zhou
PIER Letters , 2012, DOI: 10.2528/PIERL12070319
Abstract: In this paper, we propose a dual-band frequency selective surface (FSS) in low frequencies with miniaturized element. A dual-concentric square element with two different slot sizes is constructed to realize dual-band passband responses. Each passband is realized by a square slot structure. Besides, we reduce the slot sizes to make the element miniature and compact. Based on this technique, a dual-band FSS with miniaturized element in low frequencies is designed. Both the simulation and experiment results show that such a FSS owes its advantages to miniature element, stable performance with various incident angles and different polarizations, which is suitable for dual-band shipboard communication.
Expectation and application study of absolute gravity observation technology in China
我国绝对重力观测技术应用研究与展望

ZHANG Wei-min,WANG Yong,ZHOU Xu-hua,
张为民

地球物理学进展 , 2008,
Abstract: Using high precise absolute gravimeter with precision 2-5×10-8ms-2 the developing and constructing gravimetry bases and networks in our country have been introduced; The successes obtained by Chinese scholars in investigations of crust movement seismic detection and forecast and geodynamics have been reviewed; The future application perspective about absolute gravimetry has been searched and discussed.
Demonstration on the optimal design of resolution indexes of high and low sensitive axes from space-borne accelerometer in the satellite-to-satellite tracking model
卫星跟踪卫星测量模式中星载加速度计高低灵敏轴分辨率指标优化设计论证

ZHENG Wei,XU Hou-Ze,ZHONG Min,YUN Mei-Juan,ZHOU Xu-Hua,PENG Bi-Bo,
郑伟

地球物理学报 , 2009,
Abstract: 本文利用改进的能量守恒法开展了GRACE星载加速度计与K波段星间测速仪及GPS接收机精度指标之间的匹配模拟论证. 结果表明:(1)采用GRACE公布的其他载荷精度指标,当加速度计分辨率指标设计为ACCX=(1~10)×10-9m/s2, ACCY,Z=(1~10)×10-10m/s2时,在120阶处恢复累计大地水准面的精度为19~80 cm,恢复1.5°×1.5°累计重力异常的精度为0.3~1.3 mGal;(2)建议我国将来卫星重力测量计划中星载加速度计三轴分辨率指标设计为ACCX=(1~5)×1010-9m/s2,ACCY,Z=(1~5)×10-10m/s2较合适,与GRACE其他载荷精度指标基本匹配.
Influence of the adjusted accuracy of center of mass between GRACE satellite and SuperSTAR accelerometer on the accuracy of Earth''''s gravitational field
GRACE星体和SuperSTAR加速度计的质心调整精度对地球重力场精度的影响

ZHENG Wei,XU Hou-Ze,ZHONG Min,YUN Mei-Juan,ZHOU Xu-Hua,PENG Bi-Bo,
郑伟许厚泽

地球物理学报 , 2009,
Abstract: 本文利用改进的能量守恒法开展了GRACE星体和星载加速度计检验质量的不同质心调整精度影响地球重力场精度的模拟研究论证.结果表明:第一,在120阶处,当质心调整精度设计为0 m,恢复累计大地水准面精度为17.616 cm;当质心调整精度分别设计为5×10-5m、1×10-4m和5×10-4m时,恢复精度各自降低至18.106 cm、19.033 cm和27.329 cm.第二,以德国GFZ公布的EIGEN-GRACE02S地球重力场模型的实测累计大地水准面精度为标准,当质心调整精度设计为(5~10)×10-5m时,其和K波段星间测量系统、GPS接收机、SuperSTAR加速度计、恒星敏感器等GRACE核心载荷的精度指标相匹配,对地球重力场恢复精度的影响较小,因此建议我国将来研制的首颗重力卫星的星体和星载加速度计检验质量的质心调整精度设计为(5~10)×10-5m较优.
Efficient and rapid estimation of the accuracy of GRACE global gravitational field using the semi-analytical method
基于半解析法有效和快速估计GRACE全球重力场的精度

ZHENG Wei,HSU Houtse,ZHONG Min,YUN Mei-Juan,ZHOU Xu-Hua,PENG Bi-Bo,
郑伟

地球物理学报 , 2008,
Abstract: In this paper,firstly,the new combined error model of cumulative geoid height influenced by three error sources including the inter-satellite range-rate of K-band ranging system,orbital position of GPS receiver and non-conservative force of accelerometer from GRACE satellites is established using the semi-analytical method.Secondly,the dependability of error models is demonstrated based on matching relationship among the accuracy indexes of key payloads.Finally,the accuracy of global gravitational field up to degree and order 120 is effectively and rapidly estimated from GRACE Level 1B measured observation errors of the year 2006 publicized by the Jet Propulsion Laboratory(JPL) in the USA,and the cumulative geoid height error is 18.368 cm at degree 120,which preferably accords with the Earth's gravitational field model EIGEN-GRACE02S provided by the GeoForschungsZentrum Potsdam(GFZ) in Germany.This work can provide theoretical foundation and calculational guarantee for the efficient and rapid estimation of the accuracy of high-degree global gravitational field model in the future international satellite gravity measurement mission(e.g.GRACE Follow-On,degree 360).
An indirect method for refining geoid-and on application of gravity anomalier and gravity vertical gradient
精化大地水准面的一种间接方法——异常及其梯度在其中的应用

ZHANG Chi-jun,BIAN Shao-feng,GAO Jin-yao,HAO Xio-Guang,ZHOU Xu-hua,FANG Jian,
张赤军

地球物理学进展 , 2009,
Abstract: 随着GPS/水准及全球重力测量的加密和扩展,获取高精度的似大地水准面或高程异常(ξ)已比较容易,如何进一步研究它和大地水准面或大地水准面高(N)之间的关系(即所谓间接的方法)使大地水准面得到精化,这就是本文的目的,文中对已推导的公式在模型作了验证,对如何利用地形等数据确定扰动重力垂直梯度也作了研究,结果表明:在海拔4000 m的高山地区,当似大地水准面的精度达到cm级时,大地水准面的精度也与之比较接近.
Resolution estimation of Earth gravity field recovery through the low_low satellite to satellite technology by numerical simulation
数值模拟估算低低卫-卫跟踪观测技术反演地球重力场的空间分辨率

ZHOU Xu-Hua,WU Bin,XU Hou-Ze,PENG Bi-Bo Key Laboratory of Dynamic Geodesy,Institute of Geodesy & Geophysics,Chinese Academy of Sciences,Wuhan,China,
周旭华
,吴斌,许厚泽,彭碧波

地球物理学报 , 2005,
Abstract: 从两个方面模拟研究了低低卫-卫跟踪观测技术恢复地球重力场的空间分辨率.利用重力位系数作为扰动量,积分30天的轨道,研究重力位系数变化引起低低卫-卫跟踪星间距离和速率变化,结果表明,对于地球重力场模型EGM96的前12 0阶,99 8%和97%的位系数扰动引起星间距离和速率变化的均方差大于1×10 - 5m和1×10 - 7m s ,并且星间距离观测值对地球重力场的反应更为敏感.不考虑非保守力误差的影响,用随机误差为1×10 - 5m和1×10 - 6 m s的星间距离和速率变化作模拟观测量,恢复了78阶地球重力场位系数,结果表明,采用随机误差为1×10 - 5m的星间距离恢复地球重力场的精度明显高于1×10 - 6 m s的星间速率结果,但是如果考虑非保守力误差影响,则星间测速的优越性大大增强.
Effective processing of measured data from GRACE key payloads and accurate determination of Earth''s gravitational field
GRACE卫星关键载荷实测数据的有效处理和地球重力场的精确解算

ZHENG Wei,HSU Houtse,ZHONG Min,YUN Mei-Juan,ZHOU Xu-Hua,PENG Bi-Bo,
郑伟
,许厚泽,钟敏,员美娟,周旭华,彭碧波

地球物理学报 , 2009,
Abstract: 首先对美国喷气推进实验室(JPL)公布的2007-06-01~2007-12-31时间段内的GRACE Level 1B卫星GPS轨道位置和速度、K波段系统星间速度、加速度计非保守力以及恒星敏感器姿态实测数据对应进行了轨道拼接、粗差探测、线性内插、重新标定、坐标转换、误差分析等有效处理;其次,基于改进的能量守恒法恢复了120阶GRACE地球重力场,在120阶处累计大地水准面精度为25.313 cm;最后,检验了本文地球重力场模型IGG-GRACE的可靠性,同时分析了IGG-GRACE解算精度在低频部分略优于德国波兹坦地学研究中心(GFZ)公布的EIGEN-GRACE02S地球重力场模型,而在中高频部分略低的原因.
Determination of gravity vertical gradient and its application potential
重力垂直梯度的测定及其应用与潜力

ZHANG Chi-jun,BIAN Shao-feng,ZHOU Xu-hua,FANG Jian,HAO Xiao-guang,ZHANG Wei-min,
张赤军
,边少锋,周旭华,方剑,郝晓光,张为民

地球物理学进展 , 2007,
Abstract: Recent years,with the survey precision rising and indirect determining methods progressing,gravity vertical gradient is widely used in geoscience.The direct gravity gradient measurement method by means of LCR gravity meter and its operating notice are presented in this paper.The paper expounds the meaning and effect of gravity gradient to geoscience,it mainly includes:(1) precisely determining geoid and othormetric height;(2) nicely detecting material distribution and interface fluctuation;(3) resolving inversion problem in potential field sources,and interpreting dynamical mechanism of gravity gradient variation by combining gravity gradient measurement and deformation data.Its application potential in geoscience is proposed in the paper.
Aerobic biodegradation of nonylphenol ethoxylates in shaking-flask test
Wang,Ping; Nong,Xu-Hua; Ge,Jie-Hong;
Electronic Journal of Biotechnology , 2011,
Abstract: nonylphenol ethoxylates (npeos), which are widely used for industrial and domestic purposes, exert adverse effects on wildlife after being used and discharged into the environment. however, their ultimate biodegradability and biodegradation pathway remains unclear. in this study, the aerobic degradability of nonylphenol ethoxylates (npeos) by the acclimated microorganisms in active sludge was examined using shaking-flask tests. the degradation of benzene rings in npeos was determined using uv spectroscopy and high performance liquid chromatography (hplc). results showed that more than 80% of benzene rings were removed after 8-10 days of degradation, and the majority of npeos were also removed after 9 days of degradation, indicating npeos and the benzene rings could be ultimately degraded by microorganisms in acclimated active sludge. electrospray ionization-mass spectroscopy (esi-ms) analysis of biodegradation intermediates indicate that stepwise omega, beta-oxidation of eo chains or fission of eo chains, and further omega, beta-oxidation of alkyl-chain for short-eo-chain npeos constitute the main pathway in the early stage, and complete biodegradation occur when the benzene rings in these molecules are opened in the later stage.
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