Identification of distant co-evolving residues in antigen 85C from Mycobacterium tuberculosis using statistical coupling analysis of the esterase family proteins

A fundamental goal in cellular signaling is to understand allosteric communication, the process by which sig-nals originating at one site in a protein propagate reliably to affect distant functional sites. The general principles of protein structure that underlie this process remain unknown. Statistical coupling analysis （SCA） is a statistical technique that uses evolutionary data of a protein family to measure correlation between distant functional sites and suggests allosteric communication. In proteins, very distant and small interactions between collections of amino acids provide the communication which can be important for signaling process. In this paper, we present the SCA of protein alignment of the esterase family （pfam ID： PF00756） containing the sequence of antigen 85C secreted by Mycobacterium tuberculosis to identify a subset of interacting residues. Clustering analysis of the pairwise correlation highlighted seven important residue positions in the esterase family alignments. These resi-dues were then mapped on the crystal structure of antigen 85C （PDB ID： 1DQZ）. The mapping revealed corre-lation between 3 distant residues （Asp38, Leu123 and Met125） and suggests allosteric communication between them. This information can be used for a new drug against this fatal disease.

Dynamic thermo-mechanical coupled simulation of statistically inhomogeneous materials by statistical second-order two-scale method

In this paper,a statistical second-order twoscale（SSOTS） method is developed to simulate the dynamic thcrmo-mechanical performances of the statistically inhomogeneous materials.For this kind of composite material,the random distribution characteristics of particles,including the shape,size,orientation,spatial location,and volume fractions,are all considered.Firstly,the repre.sentation for the microscopic configuration of the statistically inhomogeneous materials is described.Secondly,the SSOTS formulation for the dynamic thermo-mechanical coupled problem is proposed in a constructive way,including the cell problems,effective thermal and mechanical parameters,homogenized problems,and the SSOTS formulas of the temperatures,displacements,heat flux densities and stresses.And then the algorithm procedure corresponding to the SSOTS method is brought forward.The numerical results obtained by using the SSOTS algorithm are compared with those by classical methods.In addition,the thermo-mechanical coupling effect is studied by comparing the results of coupled case with those of uncoupled case.It demonstrates that the coupling effect on the temperatures,heat flux densities,displacements,and stresses is very distinct.The results show that the SSOTS method is valid to predict the dynamic thermo-mechanical coupled performances of statistically inhomogeneous materials.

Dynamic thermo-mechanical coupled response of random particulate composites:A statistical two-scale method

This paper focuses on the dynamic thermo-mechanical coupled response of random particulate composite materials. Both the inertia term and coupling term are considered in the dynamic coupled problem. The formulation of the problem by a statistical second-order two-scale （SSOTS） analysis method and the algorithm procedure based on the finite-element difference method are presented. Numerical results of coupled cases are compared with those of uncoupled cases. It shows that the coupling effects on temperature, thermal flux, displacement, and stresses are very distinct, and the micro- characteristics of particles affect the coupling effect of the random composites. Furthermore, the coupling effect causes a lag in the variations of temperature, thermal flux, displacement, and stresses.

Corrected Statistical Energy Analysis Model in a Non-Reverberant Acoustic Space

Statistical Energy Analysis(SEA)is a well-known method to analyze the flow of acoustic and vibration energy in a complex structure.This study investigates the application of the corrected SEA model in a non-reverberant acoustic space where the direct field component from the sound source dominates the total sound field rather than a diffuse field in a reverberant space which the classical SEA model assumption is based on.A corrected SEA model is proposed where the direct field component in the energy is removed and the power injected in the subsystem considers only the remaining power after the loss at first reflection.Measurement was conducted in a box divided into two rooms separated by a partition with an opening where the condition of reverberant and non-reverberant can conveniently be controlled.In the case of a non-reverberant space where acoustic material was installed inside the wall of the experimental box,the signals are corrected by eliminating the direct field component in the measured impulse response.Using the corrected SEA model,comparison of the coupling loss factor(CLF)and damping loss factor(DLF)with the theory shows good agreement.

A New Statistical Downscaling Scheme for Predicting Winter Precipitation in China

An effective statistical downscaling scheme was developed on the basis of singular value decomposition to predict boreal winter(December-January-February)precipitation over China.The variable geopotential height at 500 hPa(GH5)over East Asia,which was obtained from National Centers for Environmental Prediction’s Coupled Forecast System(NCEP CFS),was used as one predictor for the scheme.The preceding sea ice concentration(SIC)signal obtained from observed data over high latitudes of the Northern Hemisphere was chosen as an additional predictor.This downscaling scheme showed significantly improvement in predictability over the original CFS general circulation model(GCM)output in cross validation.The multi-year average spatial anomaly correlation coefficient increased from–0.03 to 0.31,and the downscaling temporal root-mean-square-error(RMSE)decreased significantly over that of the original CFS GCM for most China stations.Furthermore,large precipitation anomaly centers were reproduced with greater accuracy in the downscaling scheme than those in the original CFS GCM,and the anomaly correlation coefficient between the observation and downscaling results reached～0.6 in the winter of 2008.

Photon pair source via two coupling single quantum emitters

We study the two coupling two-level single molecules driven by an external field as a photon pair source. The probability of emitting two photons, P2, is employed to describe the photon pair source quality in a short time, and the correlation coefficient RAB is employed to describe the photon pair source quality in a long time limit. The results demonstrate that the coupling single quantum emitters can be considered as a stable photon pair source.

Experimental and simulation studies on similitude design method for shock responses of beam-plate coupled structure

The similitude theory helps to understand the physical behaviors of large structures through scaled models. Several papers have studied the similitude of shock issues. However, the dynamic similitude for shock responses of coupled structures is rarely incorporated in open studies. In this paper, scaling laws are derived for the shock responses and spectra of coupled structures. In the presented scaling laws, the geometric distortion and energy loss are considered. The ability of the proposed scaling laws is demonstrated in the simulation and experimental cases. In both cases, the similitude prediction for the prototype's time-domain waveform and spectrum is conducted with the scaled model and scaling laws. The simulation and experimental cases indicate that the predicted shock responses and spectra agree well with those of the prototype, which verifies the proposed scaling laws for predicting shock responses.

基于统计指标的曲线桥支座脱空病害识别方法

为快速评估曲线连续梁桥支座健康状态,提出了基于时程统计指标的桥梁支座脱空病害识别方法。首先,提取行车激励下桥面测点加速度信号的20个时程统计指标,通过概率统计的方式,得出各统计指标的置信区间;其次,根据各时程统计指标对支座脱空的敏感程度不同,采用熵值法确定各统计指标的权重分配值;最后,根据各测点异常指标数计算损伤指数,综合判断测点附近支座是否出现脱空病害。为验证方法的有效性,以某3×25 m曲线连续梁桥为工程背景,建立车桥耦合动力学模型进行分析验证。结果表明:该方法可以准确识别脱空支座所在位置,并且可以有效识别较小的损伤;相比于中间支座脱空,时程统计指标对端支座脱空更为敏感。

数字普惠金融对共同富裕的影响及其区域异质性——基于富裕、平等和共享协同的视角

从系统观念出发阐释共同富裕内涵并构建与测度了包含富裕度、平等度与共享度子系统的共同富裕指数,深入分析了数字普惠金融影响共同富裕的理论机制,基于2011—2020年的省级面板数据利用GMM方法进行了实证检验。研究发现,数字普惠金融均显著提升了富裕度、平等度、共享度,有利于促进全体人民共同富裕,不同稳健性结果均支持这一结论。数字普惠金融显著地促进了共同富裕子系统的综合协调与良好耦合,体现了从系统视角协同促进共同富裕的必要性。异质性分析表明,数字普惠金融对共同富裕的促进效应在东部更大,存在随时间递减的时变特征,覆盖广度、使用深度与数字化水平的促进效应依次由大变小。

钢-混组合梁结构噪声研究

研究目的:为了分析列车高速通过钢-混组合梁桥时因振动产生的结构噪声,本文采用边界元法与统计能量法相结合的方法,建立32 m钢-混组合梁桥有限元模型、31自由度的列车模型及轨道模型,分析列车在轨道不平顺的激励下通过桥梁时的扣件力,并将扣件力作为声学边界条件,进而求解声场中各场点的声压级以及桥梁各板件对峰值声压级的贡献量。研究结论:(1)高速列车通过钢-混组合梁桥时,噪声的峰值声压级为76.5 dB(A);(2)列车以相同时速通过单箱单室和单箱双室钢-混组合梁时,桥梁结构噪声的峰值声压级基本相同,但桥梁各板件对于峰值声压级的贡献量不同;(3)列车通过单箱单室钢-混组合梁桥时,各板件对峰值声压级的贡献量为:腹板>翼缘板>底板>顶板>横隔板;(4)列车通过单箱双室钢-混组合梁桥时,各板件对峰值声压级的贡献量为:翼缘板>顶板>腹板>底板>横隔板;(5)本研究成果可为探究钢-混组合梁桥结构噪声产生机理及减振降噪措施提供参考和借鉴。

统计性方法预测高功率微波进入腔体内的分布

文章介绍了电磁场波混沌理论的发展和相关研究。在此基础上讨论了高功率微波在腔体内部形成波混沌现象的情况,并且针对这一现象,利用随机耦合模方法,对高功率微波下波混沌腔体内不同物体的耦合情况进行统计性分析。考虑到微带线的情况,利用科朗-布朗宁模型计算了随机平面波假设下微带线结构的平均吸收截面,进而对波混沌腔体内微带线的耦合情况进行统计性预测。最后设计实验,用单极天线作为参考端口,不同长度的微带线为待解端口,验证了方法的可靠性。

Modeling the Tropical Pacific Ocean Using a Regional Coupled Climate Model

A high-resolution tropical Pacific general circulation model （GCM） coupled to a global atmospheric GCM is described in this paper. The atmosphere component is the 5°× 4° global general circulation model of the Institute of Atmospheric Physics （IAP） with 9 levels in the vertical direction. The ocean component with a horizontal resolution of 0.5°, is based on a low-resolution model （2° × 1° in longitude-latitude）. Simulations of the ocean component are first compared with its previous version. Results show that the enhanced ocean horizontal resolution allows an improved ocean state to be simulated; this involves （1） an apparent decrease in errors in the tropical Pacific cold tongue region, which exists in many ocean models, （2） more realistic large-scale flows, and （3） an improved ability to simulate the interannual variability and a reduced root mean square error （RMSE） in a long time integration. In coupling these component models, a monthly ＂linear-regression＂ method is employed to correct the model＇s exchanged flux between the sea and the atmosphere. A 100-year integration conducted with the coupled GCM （CGCM） shows the effectiveness of such a method in reducing climate drift. Results from years 70 to 100 are described. The model produces a reasonably realistic annual cycle of equatorial SST. The large SSTA is confined to the eastern equatorial Pacific with little propagation. Irregular warm and cold events alternate with a broad spectrum of periods between 24 and 50 months, which is very realistic. But the simulated variability is weaker than the observed and is also asymmetric in the sense of the amplitude of the warm and cold events.

Couple analyzing the acoustic emission characters from hard composite rock fracture

Rock mass is fractured media. Its fracture is a nonlinear process. Theaccumulation of acoustic emission (AF) is closely related to the degree of damage. The dynamicsproblem is simply described based on the non-equilibrium statistical theory of crack evolvement,trying to use the hybrid analysis of the statistical theory and scan electron microscopy (SEM), thecharacters of AE signals from rock damage in a mined-out area is synthetically analyzed andevaluated. These provide an evidence to reverse deduce and accurately infer the position of rockfracture for dynamical hazard control.

The space-time coupling statistical model of reverberation from moving platforms

The space-time coupling characteristic of reverberation is one of key problems in the range of reverberation suppression with space-time processing methods.Traditional methods are not based on statistical characteristics of reverberation and not suitable to analyze the space-time coupling characteristics of reverberation in dealing with problems of reverberation extensions in the actual sea environment and non-ideal arrays.The space-time coupling relationship of moving platforms is deduced and then its space-time coupling statistical model is presented.The model describes the space-time coupling law of reverberation under the conditions as complex acoustic reverberation environments and an arbitrarily specified array.The mathematical expressions of space-time coupling relationship are described when the arrays have ideal narrow beams.The space-time distribution laws of reverberation from moving platforms are shown clearly by the analytical results and computer simulations,which validates the statistical model above.The space-time distribution law of reverberation from an uniform linear array(ULA),which is a non-ideal array,is also calculated by numerical methods.It is shown that the space-time distribution law of reverberation from any actual array can be acquired with the statistical model,and to support theoretically for reverberation suppression algorithms and systems design based on space-time processing.

Morphological parameters of both surfaces of coupled joint

Twenty one joints were made with Brazilian tests and each surface was scanned by the Talysurf CLI 2000.Morphological characteristics of joint surface were quantified by statistical and textural parameters.By the contrast of these parameters between both sides of each coupled joint,the following conclusions are drawn.The upper and lower surfaces of coupled joints have approximately equal values of Sp(maximum height of joint surface),Sa(arithmetic mean height of joint surface) and Sq(root mean square height of joint surface),but the Ssk(skewness of the height distribution of joint surface) values of the two surfaces of a coupled joint are different,one is positive while the other is negative.The Sal(auto-correlation length) parameter values of both surfaces of each coupled joint are quite close,and the Str(texture aspect ratio) values have the same situation to the S al parameter,but the same parameters of different surfaces have big differences which illustrates its own characteristics of each joint.The two surfaces of each coupled joint have similar values of ■p(mean profile angle) which can be used to deduce the value of ■p each other.

车桥系统地震响应概率统计及安全评估

为研究随机地震下车桥耦合系统的动力响应特性,通过数值方法实现了车桥耦合振动的仿真计算,确定了系统响应的概率统计规律,并用于动力可靠度分析.以实际列车和典型简支梁桥建立仿真模型,合成随机地震动加速度时程样本,获取系统的动力响应,基于蒙特卡洛模拟和可靠度理论评估结构的安全特性.结果表明:随机地震下系统响应指标的变异程度不同;桥梁跨中横向位移的变异程度最高,变异系数为0.468,竖向位移的变异程度最低,变异系数为0.097;列车的轮对横向力、轮重减载率、竖向加速度以及桥梁跨中响应均符合极值Ⅰ型分布,桥梁横向响应同时符合对数正态分布;可靠度为0.99时,系统的计算响应限值最大,动车横向加速度和桥梁跨中竖向加速度限值分别超过规范限值56%和3%,桥梁功能失效和列车脱轨的风险较高.

基于不同颗粒形态模拟方法的道砟三轴试样变形特性对比分析

道砟不规则形态是影响有砟道床变形特性的重要因素,对道砟形状及棱角分布等不同尺度形态特征的刻画与数值重构仍是道砟仿真研究的热点问题。该文采用形态重构方法,生成了符合真实道砟形态指标概率分布的多面体道砟试样,构建了不同围压下道砟三轴加载计算模型,并将该仿真结果与三维扫描生成、非统计随机生成的道砟试样的仿真结果及室内试验结果对比分析。结果表明:围压提高,颗粒形态对道砟力学响应的影响逐渐显著,该文方法重构数值试样的应力-应变结果与试验结果的符合度高于非统计随机生成试样;道砟试样横向变形与堆积结构调整有关,与三维扫描生成的道砟试样相比,非统计随机生成试样的颗粒调整程度与侧向鼓胀范围均偏大;形态统计特征对道砟接触力演化趋势影响不大,但是不同形态特征的道砟最大接触力水平差异近50%。

典型舱段结构高频振动仿真分析方法

针对高频振动试验仿真分析中面临的网格依赖性和不确定性因素敏感性等问题,以防空导弹典型舱体结构为对象,开展舱体结构与振动台的有限元-统计能量法(FE-SEA)耦合建模方法研究。通过分析频率特性,确定了舱体结构的子系统划分原则与方法,基于VA one软件平台建立了舱体结构的统计能量分析模型;采用基于波动耦合的混合模型法分析了有限元模型与统计能量法模型之间的能量传递关系,建立了舱体结构与振动台的FE-SEA耦合分析模型,对典型舱体结构的随机振动响应进行了仿真分析;开展了典型舱体的随机振动试验,舱体结构速度、加速度响应在各频段均方根(RMS)值的仿真结果与试验数据有较好的一致性。研究结果表明:FE-SEA分析方法突破了随机振动响应问题中的高频耦合建模难题,其高频振动试验的仿真预示精度达到±3 dB。

基于线缆状态数据的特征集成及异常信息自动检测技术

高压线缆在运行中容易受到气候和环境的影响,导致状态数据出现异常,为了精准检测异常线缆状态数据,保障线缆全生命周期安全,提出基于资产全生命周期的高压线缆状态数据异常自动检测方法。设计异常数据检测框架,以提供软硬支持的基础层为基础,以能力层的平台能力模块为技术支撑,大数据处理能力模块通过松耦合方法集成线缆资产全生命周期信息,提取其波动性、趋势性以及变动性特征记作特征向量并形成投影矩阵;应用层资产状态监测模块以此为依据,构建T2和平方误差预测统计量作为线缆状态特征量,将特征向量控制限作为判断状态数据异常阈值,实现线缆异常状态检测。实验结果表明:该方法可有效检测线缆异常状态数据,检测精度较高,且通过界面展示异常状态数据检测结果。

Elemental Quantitative Distribution and Statistical Analysis on Cross Section of Stainless Steel Sheet by Laser Ablation Inductively Coupled Plasma Mass Spectrometry

An innovative application of laser ablation inductively coupled plasma mass spectrometry （LA-ICP-MS） technique in illustrating elemental distributions on stainless steel sheets was presented. The technique proved to be a systematic and accurate ap- proach in producing visual images or maps of elemental distributions at cross-sectional surface of a stainless steel sheet. Two stain- less steel sheets served as research objects： 3 mm×l 300 mm hot-rolled stainless steel plate and 1 mm×l 260 mm cold-rolled plate. The cross-sectional surfaces of the two samples at 1/4 position along the width direction were scanned （raster area -44 mm2 and 11 mm2） with a focused laser beam （wavelength 213 nm, diameter of laser crater 100 μm, and laser power 1.6 mJ） in a laser abla- tion chamber. The laser ablation system was coupled to a quadrupole ICP-MS, which made the detection of ion intensities of 27A1＋, 44Ca＋, 47Ti-, 55Mn＋ and 56Fe＋ within an area of interest possible. One-dimensional （ID） content line distribution maps and two- dimensional （2D） contour maps for specific positions or areas were plotted to indicate the element distribution of a target area with high accuracy. Statistic method was used to analyze the acquired data by calculating median contents, maximum segregation, sta- tistic segregation and content-frequency distribution.