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Note on Redshift Distortion in Fourier Space

Chinese Journal of Astronomy and Astrophysics 2007年第1期7卷 51-62页

作者： yan-chuan cai Jun Pan Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

We explore features of redshift distortion in Fourier analysis of N-body simulations. The phases of the Fourier modes of dark matter density fluctuation are generally shifted by the peculiar motion along the line of sight, the induced phase shift is stochastic and has a probability distribution function （PDF） that is symmetric about the peak at zero shift and whose exact shape depends on the wave vector, except on very large scales where phases are invariant by linear perturbation theory. Analysis of the phase shifts motivates our phenomenological models for the bispectrum in redshift space. Comparison with simulations shows that our toy models are very successful in modeling bispectrum of equilateral and isosceles trian- gles at large scales. In the second part we compare the monopole of the power spectrum and bispectrum in the radial and plane-parallel distortion to test the plane-parallel approximation. We confirm the results of Scoccimarro that difference of power spectrum is at the level of 10%, and, in the reduced bispectrum, the difference is as small as a few percent. However, on the plane perpendicular to the line of sight of kz = 0, the difference in power spectrum be- tween the radial and plane-parallel approximation can be more than - 10%, and even worse on very small scales. Such difference is prominent for bispectrum, especially for configura- tions of tilted triangles. Non-Ganssian signals under the radial distortion on small scales are systematically biased downside than are in the plane-parallel approximation, with amplitudes depending on the opening angle of the sample point to the observer. This observation gives warning to the practice of using the power spectrum and bispectrum measured on the kz = 0 plane as estimates of the real space statistics.

关键词： cosmology theory-large-scale structure of universe-methods statistical

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DWT Power Spectrum of the Two-Degree Field Galaxy Redshift Survey

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Chinese Journal of Astronomy and Astrophysics 2008年第2期8卷 159-178页

作者： yan-chuan cai Jun Pan Yong-Heng Zhao Long-Long Feng Li-Zhi Fang Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 Department of Physics University of Arizona Tucson AZ 85721 US

The power spectrum of the two-degree Field Galaxy Redshift Survey （2dFGRS） sample is estimated with the discrete wavelet transform （DWT） method. The DWT power spectra within 0.035 〈 k 〈 2.2 h Mpc^-1 are measured for three volume-limited samples defined in consecutive absolute magnitude bins - 19 - - 18, - 20 - - 19 and - 21 - - 20. We show that the DWT power spectrum can effectively distinguish ACDM models of σ8 = 0.84 and σ8 = 0.74. We adopt maximum likelihood method to perform three-parameter fitting of the bias parameter b, pairwise velocity dispersion σpv and redshift distortion parameterβ = Ωm^0.6/b to the measured DWT power spectrum. The fitting results state that in a σ8 = 0.84 universe the best-fit values of Ωm given by the three samples are mutually consistent within the range 0.28 - 0.36, and the best fitted values of Opv are 398-27^＋35, 475-29^37 and 550 ± 20 km s^-1 for the three samples, respectively. In the model of σ8 = 0.74, our three samples give very different values of Ωm. We repeated the fitting using the empirical formula of redshift distortion. The result of the model of low σ8 is still poor, especially, one of the best-fit values of σpv is as large as 10^3 km s^-1. We also repeated our fitting by incorporating a scale-dependent galaxy bias. This gave a slightly lower value of Ωm. Differences between the models of σ8 = 0.84 and σ8 = 0.74 still exist in the fitting results. The power spectrum of 2dFGRS seems to disfavor models with low amplitude of density fluctuations if the bias parameter is assumed to be scale independent. For the fitting value of Ωm to be consistent with that given by WMAP3, strong scale dependence of the bias parameters is needed.

关键词： methods: data analysis -- methods: statistical : (cosmology:) cosmological parameters --(cosmology:) large-scale structure of universe

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中药影响hERG钾通道致长-QT综合征机制的研究进展

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药学学报 2019年第11期54卷 1881-1887,I0003页

作者：张钰浩颜才川王芳李宝馨杨宝峰哈尔滨医科大学药学院

药物诱发心脏毒性是近年来备受关注的问题,心脏毒性是药物由市场撤回的主要原因,而长-QT综合征是心脏毒性的重要表现之一,hERG钾通道是药物诱发心律失常和抗心律失常药物作用的重要靶点。中药是我国传统医药,临床使用历史悠久且范围广泛... 详细信息

药物诱发心脏毒性是近年来备受关注的问题,心脏毒性是药物由市场撤回的主要原因,而长-QT综合征是心脏毒性的重要表现之一,hERG钾通道是药物诱发心律失常和抗心律失常药物作用的重要靶点。中药是我国传统医药,临床使用历史悠久且范围广泛,但中药致多器官毒性仍是有待解决的难题,一些已投入临床使用的中药制剂因潜在的心脏毒性或引起严重的心律失常而被迫从市场撤回。据报道,有50余种临床常用中药产生致心律失常的心脏毒性,其中20余种是通过作用于hERG钾通道致心律失常。因此,寻找药物诱发的长-QT综合征机制及药物干预的调控靶点是当今医药领域的重点研究目标。本文总结了以Ikr/hERG钾通道为主要作用靶点的相关中药诱发长-QT综合征的机制,为临床上合理使用相关中药、避免心脏毒性以及研发药物干预的调控靶点提供理论依据。

关键词：中药心脏毒性长-QT综合征 hERG

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Research on casing deformation prevention technology based on cementing slurry system optimization

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Petroleum Science 2024年第2期21卷 1231-1240页

作者： yan yan Meng cai Wen-Hai Ma Xiao-chuan Zhang Li-Hong Han Yong-Hong Liu State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials CNPC Tubular Goods Research InstituteXi©an710077ShaanxiChina College of Mechanical and Electrical Engineering China University of Petroleum(East China)Qingdao266580ShandongChina Shale Gas Evaluation and Exploitation Key Laboratory of Sichuan Province Chengdu610095SichuanChina CNPC Daqing Oilfield Company Daqing163453HeilongjiangChina

The casing deformation prevention technology based on the optimization of cement slurry is proposed to reduce the casing deformation of shale oil and gas wells during hydraulic fracturing. In this paper, the fracture mechanism of hollow particles in cement sheath was firstly analyzed by discrete element method, and the effect of hollow particles in cement on casing deformation was investigated by laboratory experiment method. Finally, field test was carried out to verify the improvement effect of the casing deformation based on cement slurry modification. The results show that the formation displacement can be absorbed effectively by hollow particles inside the cement transferring the excessive deformation away from casing. The particles in the uncemented state provide deformation space during formation slipping. The casing with diameter of 139.7 mm could be passed through by bridge plug with the diameter of 99 mm when the mass ratio of particle/cement reaches 1:4. According to the field test feedback, the method based on optimization of cement slurry can effectively reduce the risk of casing deformation, and the recommended range of hollow microbeads content in the cement slurry is between 15% and 25%.

关键词： Cement slurry Hollow ceramsite Casing deformation Formation slip Field test

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A Scalable Numerical Method for Simulating Flows Around High-Speed Train Under Crosswind Conditions

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Communications in Computational Physics 2014年第4期15卷 944-958页

作者： Zhengzheng yan Rongliang Chen Yubo Zhao Xiao-chuan cai Shenzhen Institutes of Advanced Technology Chinese Academy of SciencesShenzhen 518055P.R.China Department of Computer Science University of Colorado BoulderBoulderCO 80309USA

This paper presents a parallel Newton-Krylov-Schwarz method for the numerical simulation of unsteady flows at high Reynolds number around a high-speed train under *** a realistic train geometry,a realistic Reynolds number,and a realistic wind speed,this is a very challenging computational *** of the limited parallel scalability,commercial CFD software is not suitable for supercomputers with a large number of *** develop a Newton-KrylovSchwarz based fully implicit method,and the corresponding parallel software,for the 3D unsteady incompressible Navier-Stokes equations discretized with a stabilized finite element method on very fine unstructured *** test the algorithm and software for flows passing a train modeled after China’s high-speed train CRH380B,and we also compare our results with results obtained from commercial CFD *** algorithm shows very good parallel scalability on a supercomputer with over one thousand processors.

关键词： Three-dimensional unsteady incompressible flows high-speed train crosswind full Navier-Stokes equations Newton-Krylov-Schwarz algorithm parallel computing

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Optimization of resource allocation in FDD massive MIMO systems

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Digital Communications and Networks 2024年第1期10卷 117-125页

作者： Jun cai chuan Yin Youwei Ding School of Artificial Intelligence and Information Technology Nanjing University of Chinese MedicineNanjing 210046China School of Electronic and Information Hangzhou Dianzi UniversityHangzhou 310018ZhejiangChina

The performance of massive MIMO systems relies heavily on the availability of Channel State Information at the Transmitter(CSIT).A large amount of work has been devoted to reducing the CSIT acquisition overhead at the pilot training and/or CsI feedback *** fact,the downlink communication generally includes three stages,i.e.,pilot training,CsI feedback,and data *** three stages are mutually related and jointly determine the overall system ***,there exist few studies on the reduction of csIT acquisition overhead from the global point of *** this paper,we integrate the Minimum Mean Square Error(MMSE)channel estimation,Random Vector Quantization(RVQ)based limited feedback and Maximal Ratio Combining(MRC)precoding into a unified framework for investigating the resource allocation *** particular,we first approximate the covariance matrix of the quantization error with a simple expression and derive an analytical expression of the received Signal-to-Noise Ratio(SNR)based on the deterministic equivalence *** the three performance metrics(the spectral efficiency,energy efficiency,and total energy consumption)oriented problems are formulated *** practical system requirements,these three metrics can be collaboratively ***,we propose an optimization solver to derive the optimal partition of channel coherence *** results verify the benefits of the proposed resource allocation schemes under three different scenarios and illustrate the tradeoff of resource allocation between three stages.

关键词： Massive MIMO FDD CSIT Resource allocation

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基于卡尔加里-剑桥指南的沙龙培训模式提升全科规培医师医患沟通技能的对照研究

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中国全科医学 2025年第1期28卷 71-76页

作者：彭涛邹川曾欣张焱沈静四川省成都市第五人民医院全科医学科 611130

背景医患沟通技能是全科医生的核心岗位胜任力之一,高水平的医患沟通能力是创建和谐医患关系的基石,有助于提高患者就医获得感和满意度。而我国全科医生沟通能力普遍偏低,有待探索出一种适应我国国情、满足我国全科医生沟通需求的医患... 详细信息

背景医患沟通技能是全科医生的核心岗位胜任力之一,高水平的医患沟通能力是创建和谐医患关系的基石,有助于提高患者就医获得感和满意度。而我国全科医生沟通能力普遍偏低,有待探索出一种适应我国国情、满足我国全科医生沟通需求的医患沟通培训模式来提高其医患沟通能力。目的探索基于卡尔加里-剑桥指南的沙龙培训模式在全科规培医师医患沟通技能培训中的应用效果,为构建适合我国国情的医患沟通培训体系提供参考依据。方法选取成都市第五人民医院2019—2020年度全科规培医师40名作为研究对象,按照随机数字表法分为沙龙组和对照组,每组20名,其中沙龙组使用基于卡尔加里-剑桥指南的沙龙培训模式进行医患沟通培训,对照组设置为空白对照,培训前、培训后1周分别对两组学员采用标准化病人(SP)模式进行接诊,使用医患沟通评价量表(SEGUE量表)进行现场观察评分,比较两组学员的医患沟通培训效果。结果最终纳入28名,其中沙龙组15名,对照组13名,培训后沙龙组规培医师SEGUE量表评分从(11.80±4.36)分提高至(18.07±4.11)分,对照组规培医师SEGUE量表评分从(12.15±4.63)分提高至(14.46±3.71)分。沙龙组培训后的SEGUE量表评分与培训前的比较,差异有统计学意义(t=3.250,P<0.001);对照组培训后的SEGUE量表评分与培训前比较,差异无统计学意义(t=2.582,P=0.624);培训后对SEGUE量表中的25个项目进行分析,沙龙组与对照组SEGUE量表评分比较,差异有统计学意义(P<0.05)。沙龙组以下5个项目结果优于对照组,准备阶段中的“建立个人信任关系”(93.3%比7.7%)、“保护患者的隐私/尊重患者选择权”(53.3%比15.4%);理解患者阶段中的“认同患者为疾病所付出的努力、改变及其遇到的困难”(33.3%比23.1%)、“表达关心,使患者感到温暖/树立信心”(100.0%比69.2%);结束问诊阶段中的“询问患者是否还有其他的问题需要探讨”(66.7%比23.1%)。结论基于卡尔加里-剑桥指南的沙龙培训模式对全科规培医师进行医患沟通技能培训可增强学员主动参加培训的兴趣和积极性,对于医患沟通能力的提升具有较好的培训效果,值得借鉴和推广。

关键词：全科医学全科医师规范化培训医患沟通沟通培训卡尔加里-剑桥指南

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Effects of heterogeneity distribution on hillslope stability during rainfalls

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Water Science and Engineering 2016年第2期9卷 134-144页

作者： Jing-sen cai E-chuan yan Tian-chyi Jim Yeh Yuan-yuan Zha Faculty of Engineering China University of Geosciences Department of Hydrology and Water Resources University of Arizona

The objective of this study was to investigate the spatial relationship between the most likely distribution of saturated hydraulic conductivity(Ks) and the observed pressure head(P) distribution within a hillslope. The cross-correlation analysis method was used to investigate the effects of the variance of ln Ks, spatial structure anisotropy of ln Ks, and vertical infiltration flux(q) on P at some selected locations within the hillslope. The cross-correlation analysis shows that, in the unsaturated region with a uniform flux boundary, the dominant correlation between P and Ksis negative and mainly occurs around the observation location of P. A relatively high P value is located in a relatively low Kszone, while a relatively low P value is located in a relatively high Kszone. Generally speaking, P is positively correlated with q/Ksat the same location in the unsaturated region. In the saturated region, the spatial distribution of Kscan significantly affect the position and shape of the phreatic surface. We therefore conclude that heterogeneity can cause some parts of the hillslope to be sensitive to external hydraulic stimuli(e.g., rainfall and reservoir level change), and other parts of the hillslope to be insensitive. This is crucial to explaining why slopes with similar geometries would show different responses to the same hydraulic stimuli, which is significant to hillslope stability analysis.

关键词： Cross-correlation analysis Heterogeneity Hillslope stability Saturated hydraulic conductivity Stochastic conceptualization Pore-water pressure

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A multi-objective multi-memetic algorithm for network-wide conflict-free 4D flight trajectories planning

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Chinese Journal of Aeronautics 2017年第3期30卷 1161-1173页

作者： Su yan Kaiquan cai School of Electronics and Information Engineering Beihang University Beijing 100191 China Beijing Key Laboratory of Network Enabled Collaborative ATM Beijing 100191 China

Under the demand of strategic air traffic flow management and the concept of trajectory based operations（TBO）,the network-wide 4D flight trajectories planning（N4DFTP） problem has been investigated with the purpose of safely and efficiently allocating 4D trajectories（4DTs）（3D position and time） for all the flights in the whole airway *** that the introduction of large-scale 4DTs inevitably increases the problem complexity,an efficient model for strategiclevel conflict management is developed in this ***,a bi-objective N4 DFTP problem that aims to minimize both potential conflicts and the trajectory cost is *** consideration of the large-scale,high-complexity,and multi-objective characteristics of the N4DFTP problem,a multi-objective multi-memetic algorithm（MOMMA） that incorporates an evolutionary global search framework together with three problem-specific local search operators is *** is capable of rapidly and effectively allocating 4DTs via rerouting,target time controlling,and flight level ***,to balance the ability of exploitation and exploration of the algorithm,a special hybridization scheme is adopted for the integration of local and global *** studies using real air traffic data in China with different network complexities show that the proposed MOMMA is effective to solve the N4 DFTP *** solutions achieved are competitive for elaborate decision support under a TBO environment.

关键词： Air traffic flow management 4D trajectory planning Multi-memetic algorithm Multi-objective optimization Network-wide strategic conflict management

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Empirical investigation of stochastic local search for maximum satisfiability

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Frontiers of Computer Science 2019年第1期13卷 86-98页

作者： Yi CHU chuan LUO Shaowei cai Haihang YOU State Key Laboratory of Computer Architecture Institute of Computing TechnologyChinese Academy of Sciences Beijing 100190China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Mathematical Engineering and Advanced Computing Wuxi 214125China State Key Laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijing 100190China

The maximum satisfiability (MAX-SAT)problem is an important NP-hard problem in theory,and has a broad range of applications in *** local search (SLS)is becoming an increasingly popular method for solving ***,a powerful SLS algorithm called CCLS shows efficiency on solving random and crafted MAX-SAT ***,the performance of CCLS on solving industrial MAX-SAT instances lags far *** this paper,we focus on experimentally analyzing the performance of SLS algorithms for solving industrial MAXSAT ***,we conduct experiments to analyze why CCLS performs poor on industrial *** we propose a new strategy called additive BMS (Best from Multiple Selections)to ease the serious *** integrating CCLS and additive BMS,we develop a new SLS algorithm for MAXSAT called CCABMS,and related experiments indicate the efficiency of ***,we experimentally analyze the effectiveness of initialization methods on SLS algorithms for MAX-SAT,and combine an effective initialization method with CCABMS,resulting in an enhanced *** results show that our enhanced algorithm performs better than its state-of-the-art SLS competitors on a large number of industrial MAX-SAT instances.

关键词： empirical investigation stochastic local search maximum satisfiability industrial instances additive BMS

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