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LEO satellite clock analysis and prediction for positioning applications

Geo-Spatial Information Science 2022年第1期25卷 14-33页

作者： kan wang Ahmed El-Mowafy School of Earth and Planetary Sciences Curtin UniversityPerthAustralia

The positioning service aided by low Earth orbit(LEO)mega-constellations has become a hot topic in recent *** achieve precise positioning,accuracy of the LEO clocks is important for single-receiver *** bridge the gap between the applicable time of the clock products and the time of positioning,the precise LEO clocks need to be predicted over a certain period depending on the sampling interval of the clock *** study discusses the prediction errors for periods from 10 s to 1 h for two typical LEO clock types,*** ultra-stable oscillator(USO)and the oven-controlled crystal oscillator(OCXO).The prediction is based on GNSS-determined precise clock estimates,where the clock stability is related to the GNSS estimation errors,the behaviors of the oscillators themselves,the systematic effects related to the environment and the relativistic effects,and the stability of the time *** on real data analysis,LEO clocks of the two different types are simulated under different conditions,and a prediction model considering the systematic effects is *** to a simple polynomial fitting model usually applied,the proposed model can significantly reduce the prediction errors,*** about 40%-70%in simulations and about 5%-30%for real data containing different miss-modeled *** both clock types,short-term prediction of 1 min would result in a root mean square error(RMSE)of a few centimeters when using a very stable time *** RMSE amounts to about 0.1 m,when a typical real-time time reference of the national center for space studies(CNES)real-time clocks was *** long-term prediction of 1 h,the RMSE could range from below 1 m to a few meters for the USOs,depending on the complexity of the miss-modeled *** OCXOs,the 1 h prediction could lead to larger errors with an RMSE of about 10 m.

关键词： LEO clock prediction USO OCXO relativistic effects

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慢性肌筋膜触发点模型大鼠的尿液代谢组学分析

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中国组织工程研究 2025年第8期29卷 1585-1592页

作者：刘琳刘世轩陆馨悦王侃南京体育学院运动健康学院江苏省南京市210014

背景:慢性肌筋膜触发点通过非靶向代谢组学技术可识别差异性代谢物变化,有助于从内源性小分子代谢物层面理解并进一步探究慢性肌筋膜触发点的病理生理过程和发病机制。目的:以慢性肌筋膜触发点模型大鼠为研究对象,基于尿液代谢组学寻找... 详细信息

背景:慢性肌筋膜触发点通过非靶向代谢组学技术可识别差异性代谢物变化,有助于从内源性小分子代谢物层面理解并进一步探究慢性肌筋膜触发点的病理生理过程和发病机制。目的:以慢性肌筋膜触发点模型大鼠为研究对象,基于尿液代谢组学寻找潜在生物标志物及相关代谢通路。方法:将16只SD大鼠随机分为造模组和正常组,造模组大鼠采用钝性打击结合离心运动(跑台坡度为-16°,跑速为16 m/min,训练时间为90 min/次)方式建立慢性肌筋膜触发点动物模型,每周1次,连续干预8周,休息4周;正常组大鼠不做干预。12周造模结束后,采用代谢笼法收集大鼠造模后24 h尿液,利用液相色谱-质谱联用非靶向代谢组学技术对尿样进行代谢图谱检测,筛选出共同差异代谢物,并进行生物信息学分析。结果与结论:①与正常组相比,造模组有32个差异代谢标志物,其中上调21个、下调11个;依据变量权重值>3,共14个差异代谢物被认定为潜在生物标志物;②京都基因与基因组百科全书富集分析表明,慢性肌筋膜触发点的形成与初级胆汁酸生物合成、花生四烯酸代谢通路密切相关。

关键词：肌筋膜触发点大鼠尿液代谢组学生物信息学生物标志物差异代谢物代谢笼法运动损伤

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A transient multiphysics coupling method based on OpenFOAM for heat pipe cooled reactors

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Science China(Technological Sciences) 2022年第1期65卷 102-114页

作者： GUO YuChuan LI ZeGuang wang kan SU ZiLin Department of Engineering Physics Tsinghua UniversityBeijing 100084China

Differing from traditional pressurized water reactors(PWRs),heat pipe cooled reactors have the unique characteristics of fuel thermal expansion,expansion reactivity feedback,and thermal contact *** reactors require a new multiphysics coupling *** this paper,a transient coupling method based on OpenFOAM is *** method considers power variation,thermal expansion,heat pipe operation,thermal contact conductance,and gap *** particular,the reactivity feedback caused by working medium redistribution in a heat pipe is also preliminarily considered.A typical heat pipe cooled reactor KRUSTY(Kilowatt Reactor Using Stirling TechnologY)is chosen as the research *** with experimental results of load following,the calculated results are in good agreement and show the validity of the proposed *** discuss the self-adjusting capability of this type of reactor system,a hypothetical accident is *** is assumed that at the beginning of this accident,loss of the heat sink *** 1500 s of the transient process,the reactor system recovers *** this hypothetical accident,the control rod is always out of the reactor core,and the reactor only relies on the reactivity feedback to regulate the fission *** to the simulation,the peak temperature is only about 1112 K,which is far below the safety *** for system recovery,the reactor needs approximately 2500 s to return to a steady state and can realize effective power regulation by reactivity *** study confirms the availability of this coupling method and that it can be an effective tool for the simulation of heat pipe cooled reactors.

关键词： heat pipe cooled reactor multiphysics coupling reactivity feedback KRUSTY reactor

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The recombinant expression systems for structure determination of eukaryotic membrane proteins

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Protein & Cell 2014年第9期5卷 658-672页

作者： Yuan He kan wang Nieng Yan State Key Laboratory of Bio-membrane and Membrane Biotechnology Tsinghua university Beijing 100084 China Center for Structural Biology School of Medicine Tsinghua university Beijing 100084 China China-Japan Friendship Hospital Beijing 100029 China

Eukaryotic membrane proteins, many of which are key players in various biological processes, constitute more than half of the drug targets and represent important candidates for structural studies. In contrast to their physiological significance, only very limited number of eukaryoUc membrane protein structures have been obtained due to the technical challenges in the genera- tion of recombinant proteins. In this review, we examine the major recombinant expression systems for eukaryotic membrane proteins and compare their relative advantages and disadvantages. We also attempted to summarize the recent technical strategies in the advancement of eukaryotic membrane protein purification and crystallization.

关键词： eukaryotic membrane proteins,recombinant expression structural biology integralmembrane proteins (IMPs) fluorescence detected sizeexclusion chromatography (FSEC) protein purification and crystallization

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Communication and monitor of breast cancer signal in the pulse-output genetic circuit network

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Science China(Information Sciences) 2014年第3期57卷 66-75页

作者： wang Xiang YUAN GuangQian wang Xun ZHAO ZeXi wang kan School of Electronic and Information Engineering Beihang University Carleton College

Pulse-output genetic circuit networks have the advantages in stability and *** this paper,we analyze some important parameters in a typical inverter,and then design a pulse-output genetic circuit of breast cancer signal communication and monitor of breast cancer *** first design a single-index monitor *** a certain tumor marker’s concentration exceeds the positive criterion,the circuit will output a pulse as a *** the diagnose results derived from one single tumor marker are sometimes indeterminate,an integrated circuit is proposed to construct a multi-index monitor circuit *** multi-index detection can strongly increase the correct recognition rate in terms of accuracy and *** circuit network may also be used in other fields of gene diagnosis with some modifications,and some experiments designed to validate them had been done.

关键词： genetic circuit network pulse multi-index breast cancer signal communication

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North America, English Translation, and Contemporary Chinese Literature

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Frontiers of Literary Studies in China-Selected Publications from Chinese Universities 2012年第4期6卷 570-581页

作者： kan wang College of Humanities Hangzhou Normal University Hangzhou 310036 China

Although contemporary Chinese writers attach great importance to the translation of their works and their introduction into the English-speaking world, especially North America, their efforts are rarely able to improve the international status of Chinese literature. There are various obstacles and prejudices faced by Chinese writers that can be roughly divided into three categories： institutional language filters, selective translation based on ＂Cold War logic,＂ and self-proclaimed literary evaluation criteria by the English speaking critics. These factors interact to influence the dissemination of contemporary Chinese literature in English-speaking world, especially North America.

关键词： North America English translation contemporary Chineseliterature

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Application of homogenization techniques for inflow transport approximation on light water reactor analysis

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Nuclear Science and Techniques 2022年第1期33卷 67-80页

作者： Xiang Xiao kan wang Tong-Rui Yang Yi-Xue Chen Department of Engineering Physics Tsinghua UniversityBeijing 100084China State Power Investment Corporation Research Institute Co.LtdBeijing 100029China

The transport cross-section based on inflow transport approximation can significantly improve the accuracy of light water reactor(LWR)analysis,especially for the treatment of the anisotropic scattering *** previous inflow transport approximation is based on the moderator cross-section and normalized fission source,which is approximated using transport *** the accuracy of reactivity is increased,the P0 flux moment has a large error in the Monte Carlo *** this study,an improved inflow transport approximation was introduced with homogenization techniques,applying the homogenized cross-section and accurate fission *** numerical results indicated that the improved inflow transport approximation can increase the P0 flux moment accuracy and maintain the reactivity calculation precision with the previous inflow transport approximation in typical LWR *** addition to this investigation,the improved inflow transport approximation is related to the temperature *** improved inflow transport approximation is flexible and accurate in the treatment of the anisotropic scattering effect,which can be directly used in the temperature-dependent nuclear data library.

关键词： Inflow transport approximation Anisotropic scattering effect Homogenization techniques Light water reactor

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Experimental modeling of polymer latex spray coating for producing controlled-release urea

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Particuology 2011年第5期9卷 510-516页

作者： Rui Lan Yonghui Liu Guanda wang Tingjie wang Chengyou kan Yong Jin Department of Chemical Engineering Tsinghua University Beijing 100084 China

Spray coating of polymer latex onto fertilizer particles in a fiuidized bed for producing controlled-release urea is an environment friendly technology as it does not need any toxic organic solvent. Since the spray coating process in a fluidized bed occurs in the presence of particle collisions, the coating of the particles is random, intermittent and multiple, thus making it difficult to investigate the film formation process. In this paper, an experimental model apparatus was designed and used to investigate the effects of the key factors in the spray coating process. This apparatus reasonably simplified the complex process to avoid particle collisions and randomness in the coating. The intermittent coating in the fluidized bed was modeled by periodic coating and dewatering in the experimental apparatus. A large area film was obtained, and the film permeability was measured. The effects of atomizing gas flow rate, spray rate of latex, solid content of latex and gas temperature on film structure and film permeability were investigated. It was found that water transfer played a dominant role in the spray coating process.

关键词： UreaLatex Controlled release Spray coating Experimental modeling

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Microstructure and Internal Friction Behavior of Laser 3D Printed Fe-Based Amorphous Composites

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 196-204页

作者： Shuilong Huang Qingjun Chen Li Ji kan wang Guosheng Huang School of Material Science and Engineering Nanchang Hangkong UniversityNanchang330063China State Key Laboratory for Marine Corrosion and Protection Luoyang Ship Material Research Institute(LSMRI)Qingdao266237China

Laser 3D printing,also known as laser additive manufacturing(LAM),is favored for its ability to form bulk metallic glass(BMG)and its composite materials(BMGcs)with freeform *** this work,two different kinds of Fe_(41)Co_(7)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2)amorphous coatings(A and B)were prepared by using LAM technology under air-and water-cooled conditions,respectively;meanwhile,to reduce the cracks generated due to the residual thermal stresses,coating C obtained by air-sweep annealing of B with a low energy-density *** morphology and amorphous content and microstructure of the coatings were investigated,the results show many cracks in coating B deposited under water-cooled conditions,and its microstructure shows an amorphous-crystal-nanocrystalline mixed *** was suppressed in coating C,obtained by air-sweep annealing based on coating B,but the amorphous content was reduced from 32.6 to 13.4%.And the hardness and corrosion resistance of the coating will increase with the increase in the amorphous ***,the internal friction behavior of a BMGcs was prepared on the basis of the process of sample C is compared with that of as-cast amorphous *** results show that the low temperature internal friction behavior of BMGcs is affected by the defects produced during printing,and the high temperature internal friction behavior is affected by the precipitated hard phase.

关键词： Laser 3D printing Amorphous coating Microstructure Corrosion resistance Internal friction behavior

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Optimization of spatial structure designs of control rod using Monte Carlo code RMC

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Frontiers in Energy 2021年第4期15卷 974-983页

作者： Hao LUO Mancang LI Shanfang HUANG Minyun LIU kan wang Department of Engineering Physics Tsinghua UniversityBeijing 100084China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology China National Nuclear Corporation Nuclear Power Institute of ChinaChengdu 610213China

Control rod is the most important approach to control reactivity in reactors,which is currently a cluster of pins filled with boron carbide(B4C).In this case,neutrons are captured in the outer region,and thus the inner absorber is ***,the lifetime of the control rod is challenged due to the high reactivity worth loss resulted from the excessive degradation of B4C in the high flux *** this work,some control rod designs are proposed with optimized spatial structures including the spatially mixed rod,radially moderated rod,and composite control rod with small-sized *** control rod worth and effective absorption cross section of these designs are computed using the Monte Carlo code RMC.A long-time depletion calculation is conducted to evaluate their burnup *** the spatially mixed rod,rare-earth absorbers are combined with B4C in spatial *** with the homogenous B4C rod,mixed designs ensure more sufficient reactivity worth in the lifetime of the *** minimum reactivity loss at the end of the cycle is only 1.8%from the dysprosium titanate rod,while the loss for pure B4C rod is nearly 12%.For the radially moderated design,a doubled neutronic efficiency is achieved when the volume ratio of moderator equals approximately 0.3,while excessive moderating may lead to the failure of control *** control rod with small-sized pins processes an enhanced safety performance and saves the investment in *** rod worth can be further enhanced by introducing small moderator pins,and the reactivity loss caused by the reduction of absorbers is sustainable.

关键词： control rod optimized spatial structure neutronic performance burnup stability

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