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A virtual reference satellite differential method for relative correction of satellite ephemeris errors

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Science china(Physics,Mechanics & Astronomy) 2010年第12期53卷 2300-2306页

作者： CAI ChengLin 1,3., LI XiaoHui 2.3.& WU HaiTao 2.3.1 Gulin university of Electronic Technology, 541004, {3. 2.National Time Service {2., Chinese Academy of Sciences, Lintong 710600, {3. 3.Key Laboratory of Precision Navigation and Timing Technology, National Time Service {2., Chinese Academy of Sciences, Lintong 710600, {3. 1. Gulin university of Electronic Technology Gulin 541004 China3. Key Laboratory of Precision Navigation and Timing Technology National Time Service Center Chinese Academy of Sciences Lintong 710600 China2. National Time Service Center Chinese Academy of Sciences Lintong 710600 China

In order to solve the problems that the novel wide area differential method on the satellite clock and ephemeris relative correction (CERC) in the non-geostationary orbit satellite constellation, a virtual reference satellite (VRS) differential principle using relative correction of satellite ephemeris errors is proposed. It is referred to be as the VRS differential principle, and the elaboration is focused on the construction of pseudo-range errors of VRS. Through qualitative analysis, it can be found that the impact of the satellite’s clock and ephemeris errors on positioning can basically be removed and the users’ positioning errors are near zero. Through simulation analysis of the differential performance, it is verified that the differential method is universal in all kinds of satellite navigation systems with geostationary orbit (GEO) constellation, Medium orbit (MEO) constellation or hybrid orbit constellation, and it has insensitivity to abnormal aspects of a satellite ephemeris and clock. Moreover, the real time positioning accuracy of differential users can be maintained within several decimeters after the pseudo-range measurement noise is effectively weakened or eliminated.

关键词： wide area differential method virtual reference satellite (VRS) satellite ephemeris errors satellite clock errors constellation

Quantitative studies of hydrocarbon loss of the Silurian bitumen sandstone in the Tarim Basin

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Science china Earth Sciences 2008年第S2期51卷 101-107页

作者： JIANG ZhenXue1,2.PANG XiongQi1,2.LIU LuoFu1,2.WANG XianDong3.ZHANG Jun4 & LI HongYi1,2.1 Basin and Reservoir research center,{2. university of Petroleum,Beijing 102.49,{2. 2.State Key Laboratory of Petroleum Resource and Prospecting,{2. university of Petroleum,Beijing 102.49,{2. 3.research Institute of Exploration and Development,Daqing Oilfield Company Ltd,Daqing 163.12.{2. 4 Petroleum Exploration and Production Institute of SINOPEC,Beijing 100083.{2. china Univ Petr Basin & Reservoir Res Ctr Beijing 102249 Peoples R China china Univ Petr State Key Lab Petr Resource & Prospecting Beijing 102249 Peoples R China Daqing Oilfield Co Ltd Res Inst Explorat & Dev Daqing 163712 Peoples R China SINOPEC Petr Explorat & Prod Inst Beijing 100083 Peoples R China

The evolution of Tarim Basin experienced several tectonic movements,of which Caledonian movement caused a serious damage to reservoirs of Silurian. The earlier reservoirs size and the later hydrocarbon loss are two key factors to exploration prospect of Silurian. On the basis of net thickness of bituminous sandstone and recovery coefficient of crude oil converting to bitumen,the scale of the hydrocarbon loss of palaeo-accumulation in bitumen sandstone of Silurian was calculated (86.3.×108t). The deter-mination of net thickness of bitumen sandstone was completed mainly by several methods,such as physical property demarcation,observing lithology,grains with oil inclusion (GOI) technology,and quantitative grains fluorescence (QGF) technology. The samples of black sandstone and white sand-stone were collected and compared by means of the methods mentioned above. The results showed that there was little hydrocarbon,or none,in the white sandstone. The recovery coefficient was ob-tained by the analyses of plentiful physical parameters of crude oil and bitumen sandstone,based on the hypothesis that nonhydrocarbon compounds and bitumen were invariable in the process of bitu-men forming. The calculated result,which is more scientific and actual,indicates the exploration pros-pect is more promising in Silurian of the Tarim Basin.

关键词： Tarim Basin Silurian bitumen sandstone hydrocarbon loss quantitative research recovery coefficient

Dipole anomaly in the Arctic atmosphere and winter Arctic sea ice motion

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Science china Earth Sciences 2005年第9期48卷 1529-1536页

作者： WU Bingyi1, ZHANG Renhe1 & WANG Jia2.1. Chinese Academy of Meteorological Sciences, Beijing 100081, china 2. International Arctic {3. {2., university of Alaska Fairbanks, AK 99775, USA 1. Chinese Academy of Meteorological Sciences 100081 Beijing China 2. International Arctic research center University of Alaska Fairbanks 99775 AK USA

This paper investigates a previously-ignored atmospheric circulation anomaly-di- pole structure anomaly in the arctic atmosphere, and its relationship with the winter sea ice mo- tion, based on analyses of the International Arctic Buoy Programme Data (1979―1998) and datasets from the National center for Environmental Prediction (NCEP) and the National center for Atmospheric {2. (NCAR) for the period of 1960―2.02. The dipole structure anomaly is the second-leading mode of EOF of monthly mean SLP north of 70°N during the winter season (Oct.―Mar.), which accounts for 13. of the variance. One of its two anomaly centers is over the Canadian Archipelago; the other is situated over northern Eurasia and the Siberian marginal seas. Due to the dipole structure anomaly’s strong meridionality, it becomes an important mechanism to drive both anomalous sea ice export out of the Arctic Basin and cold air outbreaks into the Barents Sea, the Nordic Seas and northern Europe.

关键词： dipole anomaly, winter season, Arctic, sea ice motion, sea ice export.

Large-eddy simulation of formation of three-dimensional aeolian sand ripples in a turbulent field

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Science china(Physics,Mechanics & Astronomy) 2008年第8期51卷 945-960页

作者： WU ChuiJie1,WANG Ming2.& WANG Liang3.1 State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian university of Technology,Dalian 11602.,{3. 2.Yellow River Institute of Hydraulic {2.,Zhengzhou 450003.{3. 3.{2. center for Fluid Dynamics,Science School,PLA university of Science and Technology,Nanjing 2.1101,{3. State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116024 China Yellow River Institute of Hydraulic research Zhengzhou 450003 China research center for Fluid Dynamics Science School PLA University of Science and Technology Nanjing 211101 China

With the method of large-eddy simulation,the equation of spherule motion and the method of immersed boundary condition,numerical simulations of three-dimen-sional turbulent aeolian motion and the formation of sand ripples under three-di-mensional turbulent wind and the mutual actions of saltation and creeping motion were carried out. The resulting sand ripples have the form that is flat on the upwind side and steep on the leeward,which is identical to the sand ripples in nature. We also realized the self-restoration process of three-dimensional sand ripples,which shows the correctness of the method of numerical simulation and the models of saltation and creeping. Finally,We analyzed the influence of sand ripples on the three-dimensional turbulent wind field,and found that due to the appearance and development of sand ripples,in the normal direction of ground there exists stronger energy exchange,and moreover,there is close correspondence between the forms of sand ripples and the vorticity close to the ground surface.

关键词： large-eddy simulation equation of spherule motion sand ripples saltation creep

Polynomial analysis of canopy spectra and biochemical component content inversion

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Science china Earth Sciences 2005年第10期48卷 1780-1791页

作者： YAN Chunyan1, LIU Qiang1, NIU Zheng1, WANG Jihua2. HUANG Wenjiang2.& LIU Liangyun 2.1. State Key Laboratory of Remote Sensing Science, Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal {3., Beijing 100101, china 2. National Engineering {2. center for Information Technology in Agriculture, Beijing 100089, china State Key Laboratory of Remote Sensing Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal university Beijing china National Engineering research center for Information Technology in Agriculture Beijing {2.

A polynomial expression model was developed in this paper to describe directional canopy spectra, and the decomposition of the polynomial expression was used as a tool for re-trieving biochemical component content from canopy multi-angle spectra. First, the basic formula of the polynomial expression was introduced and the physical meaning of its terms and coeffi-cients was discussed. Based on this analysis, a complete polynomial expression model and its decomposition method were given. By decomposing the canopy spectra simulated with SAILH model, it shows that the polynomial expression can not only fit well the canopy spectra, but also show the contribution of every order scattering to the whole reflectance. Taking the first scattering coefficients a10 and a01 for example, the test results show that the polynomial coefficients reflect very well the hot spot phenomenon and the effects of viewing angles, LAI and leaf inclination angle on canopy spectra. By coupling the polynomial expression with leaf model PROSPECT, a canopy biochemical component content inversion model was given. In the simulated test, the canopy multi-angle spectra were simulated by two different models, SAILH and 4-SCALE re-spectively, then the biochemical component content was retrieved by inverting the coupled polynomial expression + PROSPECT model. Results of the simulated test are promising, and when applying the algorithm to measured corn canopy multi-angle spectra, we also get relatively accurate chlorophyll content. It shows that the polynomial analysis provides a new method to get biochemical component content independent of any specific canopy model.

关键词： polynomial expression, canopy spectra, decomposition, biochemical component content, inversion.

A new algorithm for microwave radiometer remote sensing of sea surface salinity and temperature

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Science china Earth Sciences 2006年第11期49卷 1204-1211页

作者： YIN Xiaobin1, LIU Yuguang1, WANG Zhenzhan2.& XIU Peng1 1. Physical Oceanography Laboratory, Ocean university of china, Qingdao 2.6003. china 2. center for Space and Applied research, Chinese Academy of Sciences, Beijing 100080, china 1. Physical Oceanography Laboratory Ocean University of China Qingdao 266003 China 2. center for Space and Applied research Chinese Academy of Sciences Beijing 100080 China

The microwave radiation of the sea surface, which is denoted by the sea surface brightness temperature, is not only related with sea surface salinity (SSS) and temperature (SST), but also influenced by sea surface wind. The errors of wind detected by satellite sensor have significant influences on the accuracy of SSS and SST retrieval. The effects of sea surface wind on sea surface brightness temperature, i.e. △Th,v, and the relations among △Th,v, wind speed, sea surface tempera- ture, sea surface salinity and incidence angle of observation are investigated. Based on the investi- gations, a new algorithm depending on the design of a single radiometer with double polarizations and multi-incidence angles is proposed. The algorithm excludes the influence of sea surface wind on SSS and SST retrieval, and provides a new method for remote sensing of SSS and SST.

关键词： microwave radiometer, sea surface temperature, sea surface salinity, wind, brightness temperature.

Experimental study on fire smoke movement in a multi-floor and multi-room building

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Science china(Technological Sciences) 2005年第3期48卷 292-304页

作者： ZHONG Maohua 1, 2., LI Peide 2., LIU Tiemin 1 , WEI Xing 1, 2.& LIAO Guangxuan 2.1. National center of Safety Science and Technology, State Administration of Work Safety, Beijing 10002., china 2. State Key Laboratory of Fire Science, {2. of Science and Technology of china, Hefei 2.002., china 1. National center of Safety Science and Technology State Administration of Work Safety 100029 Beijing China 2. State Key Laboratory of Fire Science University of Science and Technology of China 230026 Hefei China

Fire smoke movement of multi-floor and multi-room (MFMR) fire was studied at the model test building in State Key Laboratory of Fire Science (SKLFS). The ingredient, temperature, air pressure difference and air velocity of smoke were measured and analyzed. Meanwhile, the hazard of smoke ingredient to exposed occupants was analyzed based on the national standard, Occupational Exposure Limit for Hazardous Agents in the Workplace (GBZ2.2.02.. The experimental results showed that the maximum temperature difference in MFMR fire was located along the vertical height from the fire source. With the spreading and diffusion of smoke, the temperature of smoke layer would tend to be no difference. In the fire of woodpile and kerosene, the main smoke ingredients such as SO 2., CO and CO 2.would first exceed human’s average physiological limit, while smoke ingredients such as NO and NO 2.would come behind. Because of the higher fluctuation range and frequency of air pressure difference of smoke in multi-layer building fire, the fire smoke would spread around everywhere of the passageway and made the human evacuation more difficult.

关键词： multi-floor and multi-room,fire experiment,smoke spread,smoke toxicity.

Quasi-static Analysis of Thrust-loaded Angular Contact Ball Bearings Part Ⅱ:Results and Discussion

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Chinese Journal of Mechanical Engineering 2012年第1期25卷 81-87页

作者： CHEN Wenhua1,2.MA Zikui1,GAO Liang1,LI Xinglin3.and PAN Jun2.1 Institute of Mechanical Design,Zhejiang university,Hangzhou 3.002.,china 2.Institute of Mechanical Design and Manufacturing,Zhejiang Sci-Tech university,Hangzhou 3.0018,china 3.State Testing Laboratory of Hangzhou Bearing Test & research center,Hangzhou 3.002.,china 1. Institute of Mechanical Design Zhejiang University Hangzhou 310027 China 2. Institute of Mechanical Design and Manufacturing Zhejiang Sci-Tech University Hangzhou 310018 China 3. State Testing Laboratory of Hangzhou Bearing Test & research center Hangzhou 310022 China

Ball bearings are widely employed mechanical components characterized by high precision and quality,and usually play important roles in various rotary machines and *** advanced applications require a deep understanding of their various kinematic and tribological characteristics that are essential to predict the fatigue endurance,relieve the vibration and minimize the power dissipation of ball bearings in particular *** angular contact ball bearing under a specified operating condition is simulated with the quasi-static/creepage analytical model proposed in the preceding *** results demonstrate that the ball bearing is a statically determinate *** the balls spin on both inner and outer races means the ball is controlled by neither the inner nor the outer *** friction between the ball and raceway renders the inner and outer contact angles *** larger the coefficient of friction is,the larger the angle *** tangential traction perpendicular to the rolling direction due to the spin induces a gyro-like rotation of the ball with respect to the raceway even if no inertial effects are *** tangential elastic compliance of contacting surfaces gives rise to locked areas within the contact patch and transforms the sliding lines from circles into *** differential slip due to the close conformity of the ball and raceway makes the sliding and traction distributions asymmetric,which will influence the location of the spinning center of the ball with respect to the *** quasi-static/creepage model can be used to reveal the operating behaviors of ball bearings running under steady conditions and to optimize the design of ball bearings for specific applications.

关键词： ball bearing quasi-static creepage differential slip tangential elastic compliance

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Effect of strontium substitution on the activity of La_(2.x)Sr_xNiO_4(x=0.0-1.2.in NO decomposition

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Science china Chemistry 2007年第1期50卷 41-46页

作者： ZHU JunJiang 1 ,YANG XiangGuang 2.,XU XueLian 3.&WEI KeMei 1 1 National research center of Chemical Fertilizer Catalysts,Fuzhou {2.,Fuzhou 3.0002.china 2.Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 13.02.,china 3.ollege of Chemistry&Chemical Engineering,Fuzhou {2.,Fuzhou 3.0002.china 1. National research center of Chemical Fertilizer Catalysts Fuzhou University Fuzhou 350002 China 2. Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China 3. College of Chemistry & Chemical Engineering Fuzhou University Fuzhou 350002 China

The aim of this work is to study the effect of Sr substitution on the redox properties and catalytic ac- tivity of La2.xSrxNiO4(x=0.0-1.2.for NO *** suggest that the x=0.6 sample shows the highest *** characterization(TPD,TPR,etc.)of samples indicates that the x=0.6 sample possesses suitable abilities in both oxidation and reduction,which facilitates the proceeding of oxygen desorption and NO *** temperature below 700℃,the oxygen desorption is difficult, and is the rate-determining step of NO *** the increase of reaction temperature(T> 700℃),the oxygen desorption is favorable and,the active adsorption of NO on the active site(NO+Vo+ Ni2.→NO^--Ni3.)turns out to be the rate-determining *** existence of oxygen vacancy is the prerequisite condition for NO decomposition,but its quantity does not relate much to the activity.

关键词： NO decomposition La2.xSrxNiO4 TPD TPR oxygen vacancy