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12篇 您的检索式:作者名="Peijia"
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1Orbit determination for Chang'E-2 lunar probe and evaluation of lunar gravity models显示文摘The Unified S-Band(USB) ranging/Doppler system and the Very Long Baseline Interferometry(VLBI) system as the ground tracking system jointly supported the lunar orbit capture of both Chang'E-2(CE-2) and Chang'E-1(CE-1) missions.The tracking system is also responsible for providing precise orbits for scientific data processing.New VLBI equipment and data processing strategies have been proposed based on CE-1 experiences and implemented for CE-2.In this work the role VLBI tracking data played was reassessed through precision orbit determination(POD) experiments for CE-2.Significant improvement in terms of both VLBI delay and delay rate data accuracy was achieved with the noise level of X-band band-width synthesis delay data reaching 0.2-0.3 ns.Short-arc orbit determination experiments showed that the combination of only 15 min's range and VLBI data was able to improve the accuracy of 3 h's orbit using range data only by a 1-1.5 order of magnitude,confirming a similar conclusion for CE-1.Moreover,because of the accuracy improvement,VLBI data was able to contribute to CE-2's long-arc POD especially in the along-track and orbital normal directions.Orbital accuracy was assessed through the orbital overlapping analysis(2 h arc overlapping for 18 h POD arc).Compared with about 100 m position error of CE-1's 200 km 200 km lunar orbit,for CE-2's 100 km 100 km lunar orbit,the position errors were better than 31 and 6 m in the radial direction,and for CE-2's 15 km 100 km orbit,the position errors were better than 45 and 12 m in the radial direction.In addition,in trying to analyze the Delta Differential One-Way Ranging(DOR) experiments data we concluded that the accuracy of DOR delay was dramatically improved with the noise level better than 0.1 ns and systematic errors better calibrated,and the Short-arc POD tests with DOR data showed excellent results.Although unable to support the development of an independent lunar gravity model,the tracking data of CE-2 provided evaluations of different lunar gravity models through POD.It is found that for the 100 km 100 km lunar orbit,with a degree and order expansion up to 165,JPL's gravity model LP165P did not show noticeable improvement over Japan's SGM series models(100×100),but for the 15 km×100 km lunar orbit,a higher degree-order model can significantly improve the orbit accuracy.Li PeiJia Hu XiaoGong Huang Yong Wang GuangLi Jiang DongRong Zhang XiuZhong Cao JianFeng Xin Nan 2012Science China(Physics,Mechanics & Astronomy)2012,55,3:30
2Orbit determination of Chang'E-3 and positioning of the lander and the rover显示文摘Chang’E-3 landed on the east of Sinus Iridum area on December 14,2013,performing China’s first successful soft landing on the lunar surface.We present the results on precision orbit determination and positioning of the lander and the rover.We describe the data,modeling,and methods used to achieve position knowledge over the period December 2–21,2014.In addition to the radiometric X-band range and Doppler tracking data,delta differential one-way ranging data are also used in the calculation,which show that they strongly improve the accuracy of the orbit reconstruction.Total position overlap differences are about 20 and 30 m for the 100 km 9 100 km and100 km9 15 km lunar orbit,respectively,increased by*50%with respect to CE-2 and at the same level as other lunar spacecrafts of recent era such as SELENE and lunar reconnaissance orbiter(LRO).The position error of the soft landing trajectory is less than 100 m.A kinematic statistical method is applied to determine the position of the lander and relative position of the rover with respect to the lander.The position difference of the lander is better than50 m compared to LRO photograph result.Compared with the delta very long baseline interferometry(VLBI)group delay between the lander and the rover,the delta VLBI phase delay can improve the relative position of the rover from*1,000 to*1 m.Yong Huang Shengqi Chang Peijia Li Xiaogong Hu Guangli Wang Qinghui Liu Weimin Zheng Min Fan 2014Chinese Science Bulletin2014,59,29:28
3Precise positioning of the Chang'E-3 lunar lander using a kinematic statistical method显示文摘A kinematic statistical method is proposed to determine the position for Chang'E-3(CE-3) lunar lander.This method uses both ranging and VLBI measurements to the lander for a continuous arc,combing with precise knowledge about the motion of the moon as provided by planetary ephemeris,to estimate the lander's position on the lunar surface with high accuracy.Accuracy analyses are carried out with simulation data using the software developed at Shanghai Astronomical Observatory in this study to show that measurement errors will dominate the position accuracy.Application of lunar digital elevation model(DEM) as constraints in the lander positioning is also analyzed.Simulations show that combing range/doppler and VLBI data,single epoch positioning accuracy is at several hundred meters level,but with ten minutes data accumulation positioning accuracy is able to be achieved with several meters.Analysis also shows that the information given by DEM can provide constraints in positioning,when DEM data reduce a 3-dimensional positioning problem to 2-dimensional.Considering the Sinus Iridum,CE-3 lander's planned landing area,has been observed with dedicated details during the CE-1 and CE-2 missions,and its regional DEM model accuracy may be higher than global models,which will certainly support CE-3's lander positioning.HUANG Yong HU XiaoGong LI PeiJia CAO JianFeng JIANG DongRong ZHENG WeiMin FAN Min 2012Chinese Science Bulletin2012,57,35:11
4Leaching Effect of Organic Acids on Heavy Metal Contaminated Soil显示文摘With the contamination of soil heavy metals becoming more and more serious,remediation has become a hot issue,and it is of great significance to study the remediation effects of heavy metal contaminated soil. The heavy metal contaminated soil was leached with water,acetic acid and citric acid,and the pH value of the soil after leaching was adjusted with 2% lime water. Finally,the pH value and conductivity of the soil leacheate were determined. The results showed that the best leacheate was citric acid for the remediation of soil contaminated with heavy metals Cu,Cd and Pb,and the optimum leaching concentration was 1. 0,0. 4,0. 7 mol/L,respectively. For the remediation of soil contaminated with Zn,the best leacheate was acetic acid,and the optimal leaching concentration was 1 mol/L. The leaching effect of lime water on heavy metal contaminated soil was positively correlated with the concentration of organic acid,that is,the leaching effect on heavy metals was better at stronger acidic condition. The conductivity of the soil sample treated with lime water increased with the increase of the concentration of organic acid,and at the same concentration,the conductivity was in the order of citric acid > acetic acid.Bing YU Mingxin MEN Peijia LIU Kening WU 2019Agricultural Biotechnology2019,8,1:3
5SNR periodical variation of Chang'E-3 spacecraft orbiting the Moon显示文摘Chang'E-3 spacecraft was orbiting the Moon from December 6–14, 2013, and very long baseline interferometry(VLBI) observations were performed to improve the accuracy of its orbit determination. In the process of recording VLBI raw data, 2 bits quantization was implemented.Interesting phenomenon was that signal-to-noise ratio(SNR) of each VLBI station experienced periodical change and had large variation on amplitude while in the Moon's orbit, whereas SNR kept in a stable level after Chang'E-3 landed on the Moon. Influence of varying elevation angle on SNR was analyzed and compensation of 2 bits quantization harmonics to SNR calculation was investigated. Most importantly, telescope system noise temperature increase caused by the Moon was computed along the time of Chang'E-3 orbiting the Moon, and well matched SNR changing trend in terms of correlation coefficients.he qingbao liu qinghui li peijia kawaguchi noriyuki wu yajun zheng xin zhang juan xu zhijun 2016Chinese Journal of Aeronautics2016,29,2:2
6Transit Vehicles Intelligent Scheduling Optimization Based on the Division of Characteristic Periods显示文摘XU Zhoucong HE Peijia TENG Jing 2013Procedia-Social and Behavioral Sciences2013,96,:1
7Three-dimensional spiral computed tomographic imaging: A new approach to the diagnosis and treatment planning of impacted teeth显示文摘Yuxue Chen Peijia Duan Yukun Meng Yangxi Chen 2006American Journal of Orthodontics & Dentofacial Orthopedics2006,,:1
8Eye localiza- tion from thermal infrared images显示文摘Wang Shangfei Liu Zhilei Shen Peijia 2013Pattern Recognition2013,46,10:1
9The Impact of Culture and Individualism-Collectivism on the Creative Potential and Achievement of American and Chinese Adults显示文摘Peijia Zha Jeffrey J. Walczyk Diana A. Griffith-Ross Jerome J. Tobacyk Daniel F. Walczyk 2006Creativity Research Journal2006,,3:1
10Characteristics of white coat hypertension in Chinese Han patients with type 2 diabetes mellitus显示文摘Jianguang Zhou Changyun Liu Peijia Shan Yingqi Zhou Erli Xu Yufeng Ji 2013Clinical and Experimental Hypertension2013,,:1
11Qualitative and quantitative analysis of Arnebiae Radix and Dictamni Cortex and efficacy study of herbal extracts on allergic contact dermatitis using 3D human reconstructed epidermis显示文摘Objective:To evaluate the quality of Arnebiae Radix(AR)and Dictamni Cortex(DC)and study the efficacy of herbal extracts of these two herbs on the treatment of allergic contact dermatitis(ACD).Methods:Qualitative and quantitative analysis of effective components was performed using High Performance Thin Layer Chromatography(HPTLC),High Performance Liquid Chromatography(HPLC),and HPLC-Quadrupole Time of Flight-Mass Spectrometry(HPLC-QTOF-MS).In vitro allergic ACD 3D model was established by incubating 3D reconstructed human epidermis(RHE)with skin sensitizer,potassium dichromate.A total of 65 gene expression that were associated with ACD,which included 24 antioxidant responsive element(ARE)and 41 SENS-IS genes were quantified by q RT-PCR.More than or equal to 10 ARE genes and 18 SENN-IS genes were induced by 1.3-fold,demonstrating the successful establishment of in vitro ACD model.Oil extracts of AR and DC were applied on the in vitro ACD model to study the efficacy.Results:Batch 3 of AR and batch 2 of DC showed presence of all active ingredients with the highest concentrations.Active ingredients of the herbs were extracted using a special oil and formulated into herbal oil extracts.The herbal oil extracts were able to down regulate the induced genes in the in-vitro ACD skin model,bringing the tissue back to homeostatic status.Conclusion:The oil extracts showed the potent efficacy of using AR and DC in ACD treatment.The combination study will be done to optimize the formulation ratio which will be developed into a topical cream.Huan Li Esther Lim Gladys Ang Zhi-qing Lim Martin Hui Cai Jo-anne Loh Celine Ng Peijia Seetoh Edmund Tian Lay Beng Goh 2021Chinese Herbal Medicines2021,13,4:0
12Adsorption characteristics of Cd(Ⅱ) and Ni(Ⅱ) from aqueous solution using succinylated hay显示文摘An environmentally friendly organic biosorbent was fabricated using hay by succinylation. Metallic cation adsorption tests were performed using synthetic nickel(Ⅱ) and cadmium(Ⅱ) solutions to simulate heavy-metal recovery from aqueous solution. The adsorption efficiency was greater than 98% for both cadmium and nickel ions when the biosorbent concentration was 5.0 g/L and the initial metal concentrations were 50 mg/L. The surface of the biosorbent was characterized using Fourier transform infrared spectroscopy to investigate the changes in the surface functional groups. The functional groups changed according to the surface treatment, resulting in an effective biosorbent. The kinetics of the metals adsorption revealed that the reactions are pseudo-second order, and the adsorption isotherm well followed the Langmuir model. The maximum adsorption capacities predicted by the Langmuir model were 75.19 mg/g and 57.77 mg/g for cadmium and nickel, respectively. The fabricated biosorbent was regenerated using Na Cl multiple times, with 2.1% for Cd and 4.0% for Ni in adsorption capacity after three regeneration cycles. The proposed biosorbent can be a good alternative to resin or other chemical adsorbents for heavy-metal recovery in metallurgical processing or municipal water treatment.Peijia Lin Jiajia Wu Junmo Ahn Jaeheon Lee 2019International Journal of Minerals,Metallurgy and Materials2019,26,10:0
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