全α类蛋白质超家族保守模体特征的分析

选取了全α类中序列一致性小于等于40%和25%的四个有代表性的超家族,并从中提取序列模体和结构模体,分析了其结构和功能特征的差异.结果表明,细胞色素C超家族和EF手超家族中已知功能的模体类型相对单一,而类同源域超家族和翼螺旋DNA结合域超家族中序列模体类型较多,但是主要以HTH和wHTH两种结构模体为主.进一步对模体的相对位置进行统计分析和比较,发现无论是已知功能的模体还是基于统计学方法识别的模体,它们相对于序列N端和C端的分布均呈现一定的规律性.这些特征和规律将对蛋白质超家族的识别以及结构域的研究提供有力的帮助.

核小体结合模体的理论预测和检验

核小体结合模体集合的理论预测对于全面了解核小体的定位和染色质重塑以及DNA序列的结构和进化具有重要的意义.以人类1号染色体基因间序列为样本,研究了8-mer相对模体数随频次分布的三峰现象.发现依照8-mer中CG二核苷含量分类,三个8-mer子集(记为iCG,i=1,2,3)形成独立的单峰分布,而依照其它15种二核苷含量分类则没有此现象.分析DNA序列的这一独特结构后,提出一个理论猜想,即含1CG的模体就是核小体结合模体集合.为了验证这一猜想,提取了1CG 8-mer中偏好和稀有的三核苷,分别构建了核小体特征参数Ktri(O)和Ktri(R),得到它们在基因转录起始序列(TSS)上的分布,将两类分布分别与实验给出的核小体占据率分布做线性拟合.统计结果显示,1177个TSS序列中,置信度大于95%的序列占到总数的89.2%,置信度大于99%的序列占到总数的81.6%.结果验证了1CG模体集合就是核小体结合模体的猜想.

基于复杂网络的脑电信号分析

采用相空间重构方法将一维脑电信号转换成复杂网络进行研究。将一维时间序列构造成多维相空间,计算多维时间序列任两个向量点间的距离得到加权矩阵,选择恰当的阈值将加权矩阵转换成二进制矩阵,该二进制矩阵视做时间序列所对应的复杂网络的邻接矩阵,阈值的选择使得生成的复杂网络满足连通性。利用该方法对睁眼和闭眼时的脑电信号进行辨别分析。结果表明,两信号的递归图、网络拓扑图、网络度分布和模体分布均表现出显著不同。因此,此分析方法为利用复杂网络实现分析和辨识不同脑电提供了新的思路。

CFD Analysis of Gas Distributor in Packed Column ——Prediction of Gas Flow and Effect of Tower Internals Geometry Structure

Computational fluid dynamics (CFD) simulations were carried out on the gas flow patterns of twin-tangential annular deflector gas distributor in the absence of liquid flow in a packed column (6.4 m in diameter), and the gas flow field in the column was presented close to reality on the whole. Furthermore, after ame-(lioration) of this gas distributor frame, turbulence energy and turbulence energy dissipation rate were both decreased greatly.Simulation results showed that the flow pattern and the distribution of gas flow were strongly affected by the column bottom frame; the proper column bottom frame could decrease the flow pressure drop greatly. Multifold factors, such as the column bottom geometry structure and distributor structure which affects the distribution capacity, must be considered.

CFD Simulation and Experimental Validation of Fluid Flow in Pre-distributor

Liquid distributor is a very import intemal for distillation columns. Pre-distributor is usually set on the top of distributor for initial distribution. Fluid flow in pre-distributor is a complex system of variable mass flow with many orifices and sub-branches. Consequently, the two phase modeling of pre-distributors was carried out andthe homogeneous model with free surface model was applied. The numerical method was validated by comparing with experimental data. Using the simulated results for different pre-distributors, the impacts of inflow rate, location and orientation uoon the outflow distribution were investigated. Furthermore, influences of the outflow distribution for pre-distributor on liquid uniformity in trough were also analyzed, The conclusions can De aaoptea for me structural design of liquid distributor and pre-distributor of large scale.

The Anti—tumor Effects of an Anti—CD71 Chimeric Antibody in Vitro and Its Distribution in a Tumor Xenograft Model

Objective To investigate the anti-tumor effects in vitro and in vivo distribution of the human/murine chimeric antibody (D2C). Methods The CD71 positive target cells (K562, GEM and SMMC7721) and the effector cells, freshly isolated human PBMC, with the ratio of target cells to effector cells 1:50, were incubated in various dilutions of D2C antibody ( Ab) . Antibody dependent cytotoxicity (AD-CC) was tested by using an LDH-release assay. Instead of effector cells, complement was added to the target cells (GEM, SMMC-7721) with various dilutions of D2C Ab. A method of counting death cells was used in complement dependent cytotoxicity (CDC) assay. Tumor localization and distribution of the chimeric antibody (D2C) were observed by labeling the chimeric Ab with radioiodine(131I) and injecting it into nude mice (Balb/c nu/nu) transplanted with human hepatocellular carcinoma cells (SMMC-7721).Results A significant ADCC was observed with the increased concentration of the D2C Ab. Cytolysis of CD71-positive target cells by the D2C Ab was found in the presence of fresh rabbit complement. Labeled D2C administered by intraperitoneal as well as tumor regional injection, was visualized by SPECT. The distribution of D2C Ab in murine organs and tissues showed that non-specific binding was lower following tumor regional administration than when the antibody was administered by an intraperitoneal injection. The human/murine chimeric antibody (D2C) has in vitro anti-tumor effects and can exert its effects in specific tumor localization. Its distribution and local effects in vivo can be detected by radioimmunoimaging.Conclusion CD71 human/murine chimeric antibody showed marked killing of tumor cells in vitro, and specific recognition and high affinity binding to tumor tissue in vivo

Modeling of Rocks with Spatial Distributed Fractures by Random Medium Theory

By using the spectrum expanding theory of random processes and Hudson's crack model,we developed a random medium model for rocks with spatial random distributed number density of cracks. This model could connect the micro-parameters of the cracks with the macro- mechanical properties, and can be effectively applied to model the real inhomogeneous medium. Numerical example indicates that the random distribution characters could be different for different elastic constants under the same random distribution of number density of cracks. By changing the value of the autocorrelation length pair, it is possible to model the difference of the distribution in the two coordinate directions. Numerical modeling results for seismic wave propagating in rocks with random distributed fractures using a staggered high-order finite-difference (SHOFD) are also presented.

CFD modeling of methane distribution at a continuous miner face with various curtain setback distances

Knowledge of the airflow patterns and methane distributions at a continuous miner face under different ventilation conditions can minimize the risks of explosion and injury to miners by accurately forecasting potentially hazardous face methane levels. This study focused on validating a series of computational fluid dynamics(CFD) models using full-scale ventilation gallery data that assessed how curtain setback distance impacted airflow patterns and methane distributions at an empty mining face(no continuous miner present). Three CFD models of face ventilation with 4.6, 7.6 and 10.7 m(15, 25, and 35 ft) blowing curtain setback distances were constructed and validated with experimental data collected in a full-scale ventilation test facility. Good agreement was obtained between the CFD simulation results and this data.Detailed airflow and methane distribution information are provided. Elevated methane zones at the working faces were identified with the three curtain setback distances. Visualization of the setback distance impact on the face methane distribution was performed by utilizing the post-processing capability of the CFD software.

Quasiprobability Distribution of Squeezed Thermal Spin States in Ferromagnet

We study squeezed properties of magnon squeezed thermal spin states by using the distribution of Q function in the ferromagnet. It is found that the distribution of Q function strongly depends on the temperature T and coupling parameter γ. Below the transition temperature Tc, the distribution Q function in the squeezed thermal spin state presents a richer structure than in the normal state. Non-classical effects have been observed. In the transition from the normal to the squeezed thermal spin state, the phase symmetry of the magnon system is spontaneously broken.

A Population Balance Model for Disperse Systems:Particle Size Distribution in Suspension Polymerization

On the basis of population balance a mathematical model is developed to describe the formation of polymer particle in styrene suspension polymerization. The characteristics of coalescence and breakage of droplets and the gel effect are analyzed in particular. Parameters of the models are estimated by experimental data on reaction conversion and particle size distribution. The results show that the model is suitable for predicting polymerization processes.

The Resident Time Distribution of Injected Dispersed Drops in Stirred Extraction Columns

A resident time model is proposed to evaluate the performance of agitated extraction columns. In this model, the resident time of dispersed drops is simulated with the discrete phase modeling, where the continuous phase and the dispersed phase （drops） are described by the single-phase Navier-Stokes （turbulence） model and Lagrangian model, respectively. The interaction of dispersed phase and continuous phase is neglected for the low concentration of drop in the cases studied. The statistical parameters of drops （the average resident time and standard deviation） under different operation conditions are computed for four columns. The relation of the above statistical parameters with the performance of columns is discussed and the criterions for an optimal compartment are outlined. Our results indicate that the resident time model is useful to evaluate the performance and optimize the design of extraction columns.

CFD Simulation of Orifice Flow in Orifice-type Liquid Distributor

In this study,a suitable CFD(computational fluid dynamics)model has been developed to investigate the influence of liquid height on the discharge coefficient of the orifice-type liquid distributors.The orifice flow in different diameters and liquid heights has been realized using the shear stress transport(SST)turbulence model and the Gamma Theta transition(GTT)model.In the ANSYS CFX software,two models are used in conjunction with an automatic wall treatment which allows for a smooth shift from a wall function(WF)to a low turbulent-Re near wall formulation(LTRW).The results of the models coupled with LTRW are closer to the experimental results compared with the models with WF,indicating that LTRW is more appropriate for the prediction of boundary layer characteristics of orifice flow.Simulation results show that the flow conditions of orifices change with the variation of liquid height.With respect to the turbulence in orifice,the SST model coupled with LTRW is recommended.However,with respect to the transition to turbulence in orifice with an increase in liquid height,the predictions of GTT model coupled with LTRW are superior to those obtained using other models.

Coordinate-Momentum Intermediate Representation and Marginal Distributions of Quantum Mechanical Bivariate Normal Distribution

We introduce bivariate normal distribution operator for state vector [ψ） and find that its marginal distribution leads to one-dimensional normal distribution corresponding to the measurement probability ｜λ,v〈x｜.ψ〉｜^2, where ｜x〉λ,v is the coordinate-momentum intermediate representation. As a by-product, the one-dimensional normal distribution in statistics can be explained as a Radon transform of two-dimensional Gaussian function.

An improved cross entropy algorithm for steelmaking-continuous casting production scheduling with complicated technological routes

In order to increase productivity and reduce energy consumption of steelmaking-continuous casting(SCC) production process, especially with complicated technological routes, the cross entropy(CE) method was adopted to optimize the SCC production scheduling(SCCPS) problem. Based on the CE method, a matrix encoding scheme was proposed and a backward decoding method was used to generate a reasonable schedule. To describe the distribution of the solution space, a probability distribution model was built and used to generate individuals. In addition, the probability updating mechanism of the probability distribution model was proposed which helps to find the optimal individual gradually. Because of the poor stability and premature convergence of the standard cross entropy(SCE) algorithm, the improved cross entropy(ICE) algorithm was proposed with the following improvements: individual generation mechanism combined with heuristic rules, retention mechanism of the optimal individual, local search mechanism and dynamic parameters of the algorithm. Simulation experiments validate that the CE method is effective in solving the SCCPS problem with complicated technological routes and the ICE algorithm proposed has superior performance to the SCE algorithm and the genetic algorithm(GA).

Dynamic Monte Carlo study on the probability distribution functions of tail-like polymer chain

The configurational properties of tail-like polymer chains with one end attached to a flat surface are studied by using dynamic Monte Carlo technique. We find that the probability distribution of the free end in z direction P（Rz） and the density profile p（z） can be scaled approximately by a factor β to be a length independent function for both random walking （RW） and self-avoiding walking （SAW） tail-like chains, where the factor β is related to the mean square end-to-end distance 〈RE〉. The scaled P（Rz） of the SAW chain roughly overlaps that of the RW chain, but the scaled p（z） of the SAW chain locates at smaller βz than that of the RW chain.

Relationship between ethnic landscape and environment in the Nujiang River basin of Yunnan Province, China

Each nationality has formed unique ethnic culture in the long history. Ethnic culture is spatially reflected byethnic distribution. The distribution of nationalities is influenced by ethnic history, culture, society and religion, alsoaffected by regional physical setting. This paper analyzes the relationship between ethnic distribution pattern and naturalsetting with contrast analytical method. The digital elevation model (DEM) is established on basis of contour map on ascale of 1:250,000 in the Nujiang River basin, Yunnan Province by ArcGIS, a Geographic Information System (GIS)software. Based on DEM, the spatial analysis and statistical function of GIS, the landscape patterns of populationdistribution of the selected minorities is described, and 4 sub-regions are divided in the Nujiang River basin of YunnanProvince while the features and disparity of landscape pattern and its forming mechanism are discussed, along withhistorical and archaeological data. The conclusions are as follow: (1) The ethnic distribution is mosaic in the matrix ofother racial distribution, and have a distinct spatial correlation. (2) For the difference in cultivation between differentnationalities, certain nationality lived in the area suitable for production mode of its own and coincident with appropriategeographical setting. (3) The spatial distribution of settlement spots of the minorities is controlled by the convenience ofwater supply. The landscape pattern of ethnic distribution is closely relative to natural environment.

Simulation of electromagnetic-flow fields in Mg melt under pulsed magnetic field

The effects of a pulsed magnetic field on the solidified microstructure of pure Mg were investigated.The results show that microstructure of pure Mg is considerably refined via columnar-to-equiaxed growth under the pulsed magnetic field and the average grain size is refined to 260？？ under the optimal processing conditions.A mathematical model was built to describe the interaction of the electromagnetic-flow fields during solidification with ANSYS software.The pulsed electric circuit was first solved and then it is substituted into the magnetic field model.The fluid flow model was solved with the acquired electromagnetic force.The effects of pulse voltage frequency on the current wave and on the distribution of magnetic and flow fields were numerically studied.The pulsed magnetic field increases melt convection,which stirs and fractures the dendritic arms into pieces.These broken pieces are transported into the bulk liquid by the liquid flow and act as nuclei to enhance grain refinement.The Joule heat effect produced by the electric current also participates in the microstructural refinement.

Designing an optimal stope layout for underground mining based on a heuristic algorithm

An optimal layout or three-dimensional spatial distribution of stopes guarantees the maximum profitability over life span of an underground mining operation.Thus,stope optimization is one of the key areas in underground mine planning practice.However,the computational complexity in developing an optimal stope layout has been a reason for limited availability of the algorithms offering solution to this problem.This article shares a new and efficient heuristic algorithm that considers a three-dimensional ore body model as an input,maximizes the economic value,and satisfies the physical mining and geotechnical constraints for generating an optimal stope layout.An implementation at a copper deposit demonstrates the applicability and robustness of the algorithm.A parallel processing based modification improving the performance of the original algorithm in terms of enormous computational time saving is also presented.

A Mathematical Model to Study the Effect of Pore Sizes Distribution on Densification Process in Ceramic Compacts

In this research the effect of pore size distribution on densification process during sintering of ceramic compacts is studied by assuming a Gaussian distribution of the pore sizes and depending on a mathematical model that was developed in a previous research in describing the densification process.

An Investigation on Thermization of Milk in Can Using Computational Fluid Dynamics

Thermal processing of milk is an important unit operation to inactivate the spoilage organism and enzymes and thus increase the storage life of milk, It was very difficult to find out the temperature distribution inside the cans during thermal processing. A Computational Fluid Dynamics （CFD） model was developed for thermization of milk in the can heating at 65℃ for the first time to determine the temperature distribution in the canned milk at stationary position. This developed CFD model was validated with the experimental measurements of temperature. The effects of thermization temperature on milk flow profile （velocity）, milk temperature and viscosity profiles inside the can during thermal process were investigated. Temperature profiles of milk in can at three different planes （i.e. top, middle and bottom plane） were studied. Moreover, thermization unit was calculated by correlating with temperature and it was found that maximum thermization unit was achieved at 540 s of thermal processing of milk in can.