AHermitian C^(2) Differential Reproducing Kernel Interpolation Meshless Method for the 3D Microstructure-Dependent Static Flexural Analysis of Simply Supported and Functionally Graded Microplates

This work develops a Hermitian C^(2) differential reproducing kernel interpolation meshless(DRKIM)method within the consistent couple stress theory(CCST)framework to study the three-dimensional(3D)microstructuredependent static flexural behavior of a functionally graded(FG)microplate subjected to mechanical loads and placed under full simple supports.In the formulation,we select the transverse stress and displacement components and their first-and second-order derivatives as primary variables.Then,we set up the differential reproducing conditions(DRCs)to obtain the shape functions of the Hermitian C^(2) differential reproducing kernel(DRK)interpolant’s derivatives without using direct differentiation.The interpolant’s shape function is combined with a primitive function that possesses Kronecker delta properties and an enrichment function that constituents DRCs.As a result,the primary variables and their first-and second-order derivatives satisfy the nodal interpolation properties.Subsequently,incorporating ourHermitianC^(2)DRKinterpolant intothe strong formof the3DCCST,we develop a DRKIM method to analyze the FG microplate’s 3D microstructure-dependent static flexural behavior.The Hermitian C^(2) DRKIM method is confirmed to be accurate and fast in its convergence rate by comparing the solutions it produces with the relevant 3D solutions available in the literature.Finally,the impact of essential factors on the transverse stresses,in-plane stresses,displacements,and couple stresses that are induced in the loaded microplate is examined.These factors include the length-to-thickness ratio,the material length-scale parameter,and the inhomogeneity index,which appear to be significant.

A novel box-counting method for quantitative fractal analysis of threedimensional pore characteristics in sandstone

Fractal theory offers a powerful tool for the precise description and quantification of the complex pore structures in reservoir rocks,crucial for understanding the storage and migration characteristics of media within these rocks.Faced with the challenge of calculating the three-dimensional fractal dimensions of rock porosity,this study proposes an innovative computational process that directly calculates the three-dimensional fractal dimensions from a geometric perspective.By employing a composite denoising approach that integrates Fourier transform(FT)and wavelet transform(WT),coupled with multimodal pore extraction techniques such as threshold segmentation,top-hat transformation,and membrane enhancement,we successfully crafted accurate digital rock models.The improved box-counting method was then applied to analyze the voxel data of these digital rocks,accurately calculating the fractal dimensions of the rock pore distribution.Further numerical simulations of permeability experiments were conducted to explore the physical correlations between the rock pore fractal dimensions,porosity,and absolute permeability.The results reveal that rocks with higher fractal dimensions exhibit more complex pore connectivity pathways and a wider,more uneven pore distribution,suggesting that the ideal rock samples should possess lower fractal dimensions and higher effective porosity rates to achieve optimal fluid transmission properties.The methodology and conclusions of this study provide new tools and insights for the quantitative analysis of complex pores in rocks and contribute to the exploration of the fractal transport properties of media within rocks.

A TENSOR ANALYSIS METHOD FOR ESTIMATING 3-D MOTION PARAMETERS

By using the center projection image sequence to estimate 3-D motion parameters,one needs to know the corresponding relationship between the feature of motion object in spaceand the projection coordinate on image plane.In order to avoid using the relationship of featurecorrespondence,the tensor analysis method in the affine transformation system is presented,andthe simulation data of experimental results are given.

3-D fracture network dynamic simulation based on error analysis in rock mass of dam foundation

Accurate 3-D fracture network model for rock mass in dam foundation is of vital importance for stability,grouting and seepage analysis of dam foundation.With the aim of reducing deviation between fracture network model and measured data,a 3-D fracture network dynamic modeling method based on error analysis was proposed.Firstly,errors of four fracture volume density estimation methods(proposed by ODA,KULATILAKE,MAULDON,and SONG)and that of four fracture size estimation methods(proposed by EINSTEIN,SONG and TONON)were respectively compared,and the optimal methods were determined.Additionally,error index representing the deviation between fracture network model and measured data was established with integrated use of fractal dimension and relative absolute error(RAE).On this basis,the downhill simplex method was used to build the dynamic modeling method,which takes the minimum of error index as objective function and dynamically adjusts the fracture density and size parameters to correct the error index.Finally,the 3-D fracture network model could be obtained which meets the requirements.The proposed method was applied for 3-D fractures simulation in Miao Wei hydropower project in China for feasibility verification and the error index reduced from 2.618 to 0.337.

GSK3/Nrf2调控的生物节律在机体衰老中的规律

背景:生物节律(昼夜节律)紊乱是一个典型的与衰老有关的问题,维持生物节律的正常运作可能是一种很有前景的抗衰老策略。核转录因子NF-E2相关因子2的表达具有生物节律;糖原合成酶激酶3系统代表了一个“调节阀”,它控制核转录因子NF-E2相关因子2水平的细微振荡。抗氧化基因转录水平的昼夜变化可以影响生物体对氧化应激的反应,但是糖原合成酶激酶3/NF-E2相关因子2在调节机体衰老中的具体分子机制仍令人困惑。目的:拟通过对该领域文献的回顾,寻找糖原合成酶激酶3/核转录因子NF-E2相关因子2调控的生物节律在机体衰老中的一般规律。方法:文献资料法通过对有关“糖原合成酶激酶3、核转录因子NF-E2相关因子2、生物节律以及衰老”等相关文献进行检索、查阅和筛选,为全文的分析奠定理论基础。对比分析法通过对所得到文献进行阅读分析,比较文献之间的异同点,为论点提供合理的理论支撑。通过对文献的进一步对比分析,理清相关指标间的关系,为全文的分析明确思路。结果与结论:①糖原合成酶激酶3可通过对节律基因的调节间接调控核转录因子NF-E2相关因子2的表达;②糖原合成酶激酶3和核转录因子NF-E2相关因子2是抗衰老程序的组成部分,且与生物节律相关;③并且糖原合成酶激酶3/核转录因子NF-E2相关因子2参与多种代谢途径,包括与衰老相关疾病(2型糖尿病和癌症)和神经退行性疾病相关的代谢途径。

A Periodicity Analysis of the Light Curve of 3C 454.3

We analyzed the radio light curves of 3C 454.3 at frequencies 22 and 37 GHz taken from the database of Metsaeovi Radio Observatory, and found evidence of quasi-periodic activity. The light curves show great activity with very complicated non-sinusoidal variations. Two possible periods, a very weak one of 1.57 ± 0.12 yr and a very strong one of 6.15 ±0.50 yr were consistently identified by two methods, the Jurkevich method and power specmun estimation. The period of 6.15 ± 0.50 yr is consistent with results previously reported by Ciaramella et al. and Webb et al. Applying the binary black hole model to the central structure we found black hole masses of 1.53 × 10^9M⊙ and 1.86 × 10^8M⊙, and predicted that the next radio outburst is to take place in 2006 March and April.

基于CeBr_(3)的γ能谱测井解谱方法研究

在铀钍混合型的矿床中,钍对γ总量测井结果的影响难于直接扣除。因探测器体积和测量时间的制约,传统的解谱方法灵敏度较低,相对误差较大。基于已研制的溴化铈探测器的γ能谱测井仪,针对能谱数据特征峰特点对解谱方法进行了实验研究。采用拓展能窗解谱法,大幅提高了铀含量检测灵敏度,降低了铀含量测量结果的相对误差。结果表明:采用拓展能窗解谱方法,相比于传统标准能窗解谱方法,平均铀含量检测灵敏度提高到3倍多,混合模型体源的铀含量测量结果的相对误差绝对值从9.2%降至了4.7%,在铀钍混合模型体源上测得的铀、钍含量相对误差绝对值小于5%,在铀和钍单核素模型体源测得的主核素含量相对误差绝对值小于5%。拓展能窗解谱方法可以提高测井精度,对准确测量铀钍混合型矿床中的铀和钍含量具有一定的现实意义。

A Study of the Comets with Large Perihelion Distances C/2019 L3(ATLAS)and C/2019 O3(Palomar)

This work analyzes the photometric data of the Oort spike comets C/2019 L3(ATLAS)and C/2019 O3(Palomar)obtained between 2016 and 2023 by the ATLAS network and the Belgian Olmen Observatory.The comets Palomar and ATLAS have a typical and unusually high activity level,respectively,based on the Afρparameter corrected to phase angle zero at perihelion.The absolute magnitude of comets ATLAS and Palomar in the o-band is 4.71±0.05 and 4.16±0.02 respectively.The cometary activity of comets ATLAS and Palomar probably began at r>13 au before perihelion and will end at r>14 au after perihelion,which means that they could remain active until the second half of 2026.The nucleus of comet ATLAS has a minimum radius of 7.9 km,and the nucleus of comet Palomar could be a little larger.The c-o colors of the comets ATLAS and Palomar are redder and bluer,respectively,at perihelion than the solar twin YBP 1194.These comets showed a bluish trend in the coma color with decreasing heliocentric distance.Comet Palomar probably had two outbursts after its perihelion,each releasing about 10^(8)kg of dust.The slopes of the photometric profile of the comae of these comets were between 1and 1.5,indicating a steady state during the observation campaign.

基于多重扫描速率法的α-Al_(2)O_(3)煅烧动力学研究

以氢氧化铝粉体为原料,探究氢氧化铝煅烧为α-Al_(2)O_(3)过程中的相转变与微观组织变化,利用多重扫描速率法对其煅烧过程进行动力学模拟计算。结果表明,氢氧化铝煅烧为α-Al_(2)O_(3)的优化条件为:煅烧温度1200℃、煅烧时间2 h、升温速率5℃/min。氢氧化铝煅烧过程出现3个吸热峰,对应3个失重阶段:第一阶段反应机理函数为G(α)=[(1-α)^(-1/3)-1]^2,反应平均活化能为91.16 kJ/mol,指前因子17.00×10^(9)~44.03×10^(9)min^(-1);第二阶段反应机理函数为G(α)=α~2,反应平均活化能为106.2 kJ/mol,指前因子7.70×10^(9)~18.60×10^(9)min^(-1);第三阶段反应机理函数为G(α)=α~(1/4),反应平均活化能为235.42 kJ/mol,指前因子39.94×10^(9)~50.79×10^(9)min^(-1)。

3D analysis of functionally graded material plates with complex shapes and various holes

In this paper, the basic formulae for the semi-analytical graded FEM on FGM members are derived. Since FGM parameters vary along three space coordinates, the parameters can be integrated in mechanical equations. Therefore with the parameters of a given FGM plate, problems of FGM plate under various conditions can be solved. The approach uses 1D discretization to obtain 3D solutions, which is proven to be an effective numerical method for the mechanical analyses of FGM structures. Examples of FGM plates with complex shapes and various holes are presented.

Static Analysis of Doubly-Curved Shell Structures of Smart Materials and Arbitrary Shape Subjected to General Loads Employing Higher Order Theories and Generalized Differential Quadrature Method

The article proposes an Equivalent Single Layer(ESL)formulation for the linear static analysis of arbitrarily-shaped shell structures subjected to general surface loads and boundary conditions.A parametrization of the physical domain is provided by employing a set of curvilinear principal coordinates.The generalized blendingmethodology accounts for a distortion of the structure so that disparate geometries can be considered.Each layer of the stacking sequence has an arbitrary orientation and is modelled as a generally anisotropic continuum.In addition,re-entrant auxetic three-dimensional honeycomb cells with soft-core behaviour are considered in the model.The unknown variables are described employing a generalized displacement field and pre-determined through-the-thickness functions assessed in a unified formulation.Then,a weak assessment of the structural problem accounts for shape functions defined with an isogeometric approach starting fromthe computational grid.Ageneralizedmethodology has been proposed to define two-dimensional distributions of static surface loads.In the same way,boundary conditions with three-dimensional features are implemented along the shell edges employing linear springs.The fundamental relations are obtained from the stationary configuration of the total potential energy,and they are numerically tackled by employing the Generalized Differential Quadrature(GDQ)method,accounting for nonuniform computational grids.In the post-processing stage,an equilibrium-based recovery procedure allows the determination of the three-dimensional dispersion of the kinematic and static quantities.Some case studies have been presented,and a successful benchmark of different structural responses has been performed with respect to various refined theories.

Numerical Investigation of Laser Surface Hardening of AISI 4340 Using 3D FEM Model for Thermal Analysis of Different Laser Scanning Patterns

Laser surface hardening is becoming one of the most successful heat treatment processes for improving wear and fatigue properties of steel parts. In this process, the heating system parameters and the material properties have important effects on the achieved hardened surface characteristics. The control of these variables using predictive modeling strategies leads to the desired surface properties without following the fastidious trial and error method. However, when the dimensions of the surface to be treated are larger than the cross section of the laser beam, various laser scanning patterns can be used. Due to their effects on the hardened surface properties, the attributes of the selected scanning patterns become significant variables in the process. This paper presents numerical and experimental investigations of four scanning patterns for laser surface hardening of AISI 4340 steel. The investigations are based on exhaustive modelling and simulation efforts carried out using a 3D finite element thermal analysis and structured experimental study according to Taguchi method. The temperature distribution and the hardness profile attributes are used to evaluate the effects of heating parameters and patterns design parameters on the hardened surface characteristics. This is very useful for integrating the scanning patterns’ features in an efficient predictive modeling approach. A structured experimental design combined to improved statistical analysis tools is used to assess the 3D model performance. The experiments are performed on a 3 kW Nd:Yag laser system. The modeling results exhibit a great agreement between the predicted and measured values for the hardened surface characteristics. The model evaluation reveals also its ability to provide not only accurate and robust predictions of the temperature distribution and the hardness profile as well an in-depth analysis of the effects of the process parameters.

活性污泥3号模型全局敏感性分析

全局敏感性分析可用于确定影响活性污泥3号模型(ASM3)预测结果的关键参数,从而提高参数校准的精度和效率。为了获得ASM3全局敏感性分析结果,利用Sobol’s法对ASM3进行全局敏感性分析,确定了影响SNH4、CODT等关键预测结果的重要参数。同时,通过比较使用Morris筛选法和Sobol’s法获得的全局敏感性分析结果,发现当重复次数足够大时,Morris筛选法也是一种可用于ASM3参数优先级排序和参数固定化的可靠方法。

Ergodic sensitivity analysis of one-dimensional chaotic maps

Sensitivity analysis in chaotic dynamical systems is a challenging task from a computational point of view.In this work,we present a numerical investigation of a novel approach,known as the space-split sensitivity or S3 algorithm.The S3 algorithm is an ergodic-averaging method to differentiate statistics in ergodic,chaotic systems,rigorously based on the theory of hyperbolic dynamics.We illustrate S3 on one-dimensional chaotic maps,revealing its computational advantage over na?ve finite difference computations of the same statistical response.In addition,we provide an intuitive explanation of the key components of the S3 algorithm,including the density gradient function.

Aspergillus flavus M-3生物浸出煤中汞的条件优化

汞是煤炭中有毒的重金属元素之一,如何脱除煤中汞是煤炭清洁高效利用研究领域难点。为探索煤中汞的最优浸出条件,以贵州老鹰山高汞煤为研究对象,采用从该地区土壤中筛选分离对煤中汞有浸出作用的菌株M-3(经分子生物学鉴定为Aspergillus flavus M-3),通过响应面方法对菌株M-3浸出煤中汞的影响因素和浸出条件进行筛选和优化。试验结果表明:煤添加量、表面活性剂和接种量为影响菌株M-3浸出汞的重要因素;当煤添加量为3 g、表面活性剂添加量为1 mL、接种量为10%时,汞的浸出效果最好,浸出率达到84.89%。利用生物法浸出煤中汞具有一定可行性,可以为煤炭清洁高效利用提供一定支持。

新型橙红色荧光粉Sr_(3)CaNb_(2)O_(9)∶Sm^(3+)的制备及发光性能研究

通过高温固相法制备了一系列Sr_(3)CaNb_(2)O_(9)∶xSm^(3+)(0.04≤x≤0.1)新型橙红色荧光粉。研究了其物相、形貌、发光性能、热稳定性和CIE色度坐标。X射线衍射(XRD)物相分析和Rietveld精修结果表明合成了Sr_(3)CaNb_(2)O_(9)的纯相。在407nm的紫光激发下,Sr_(3)CaNb_(2)O_(9)∶Sm^(3+)在645nm处发红光,可归因于Sm^(3+)的^(4)G_(5/2)→^(6)H_(9/2)跃迁。实验表明Sr_(3)CaNb_(2)O_(9)∶xSm^(3+)的最佳掺杂浓度为x=0.07,根据Dexter理论分析,其浓度猝灭机理为电偶极-电偶极相互作用。Sr_(3)CaNb_(2)O_(9)∶Sm^(3+)在423K下发光强度是室温下的90.3%,表现出良好的热稳定性。Sr_(3)CaNb_(2)O_(9)∶xSm^(3+)的发光色坐标均位于橙红色区域,且具有较高的色纯度。结果表明Sr_(3)CaNb_(2)O_(9)∶Sm^(3+)荧光粉在白光发光二极管(WLED)中具有潜在的应用前景。

基于Rietveld精修方法解析Sc_(2)O_(3)的原子热振动

分别在26℃、300℃和600℃下,用XRD方法对Sc_(2)O_(3)粉末晶体开展了晶体结构衍射实验。采用RIETAN-2000软件中的Rietveld精修法分析了实验结果,精修了Sc_(2)O_(3)粉末晶体在不同温度下的各晶体结构参数,确定了原子热振动各向同性温度因子B。采用Maximum Entropy Method(MEM)分析技术,得到Sc_(2)O_(3)粉末晶体的3D、2D等高电子密度分布可视化图谱。

阶段矿房法二步骤采场地压控制研究

在阶段矿房二步骤开采时,为了减小上盘岩移量,常采纳采场中部切槽并向上盘、下盘两侧回采,从而缩短采场暴露时间,以便减小上盘岩移量。当地压达到流变发生的条件后,缩短采场暴露时间并不能有效控制上盘巷道发生岩移破坏。为此,利用三维连续体快速拉格朗日分析数值模拟采场上盘地压,并根据流变理论分析,采纳低松弛预应力大直径钢绞线锚索支护上盘顶板以便减小上盘地压,从而克服发生流变变形的应力条件。结果表明:在上盘岩体上施加支护抗力可减小或消除高地压导致的流变变形;采纳7排7.0 m长的锚索、每排6根支护上盘顶板后大幅度减小了上盘岩移量,但采场第2分层上排锚索及一步骤采场第3分层局部锚索的锚固力超过设计值;采纳8排7.0 m长的锚索、一步骤采场每排7根、二步骤采场每排6根支护上盘顶板后,即使回采底柱,锚索锚固力也不会达到设计值。监测表明,大直径钢绞线锚索支护后上盘岩移量减小到一般不超过6 mm。

啤酒酵母中(1→3)-β-D-葡聚糖的提取及其机理研究

分别采用酸法、酸碱法来提取啤酒酵母中的(1→3) β D 葡聚糖,然后对其产品进行多糖成分和紫外光谱分析。结果发现,在用c(CH3COOH)=0 5mol/L的水溶液提取啤酒酵母中的(1→3) β D 葡聚糖时,其产品中除含有葡聚糖外,还含有一定量的甘露聚糖和蛋白质这两种成分。但先用c(NaOH)=1 0mol/L的水溶液提取,再用w(CH3COOH)=4%的醋酸溶液处理时,产品为高纯度的(1→3) β D 葡聚糖。此结论由傅立叶红外光谱和核磁共振碳谱得到进一步的证实。接着从其水解机理上阐述了产生上述两种不同结果的原因,从而说明了酸碱法是从啤酒酵母中提取(1→3) β D 葡聚糖的理想途径。

基于UML模型的CTCS-3级列控系统功能安全分析方法

本文利用UML支持的底层扩展机制对UML进行面向列控系统混成性的扩展,使用扩展后的UML对列控系统进行半形式化建模,并采用故障事件机制对系统的故障情况进行刻画。给出UML模型到PHAVer模型的转化规则以及故障监视器模型的建立方法,利用可达集计算原理验证列控系统的PHAVer模型并对其进行功能安全性分析。以CTCS-3级列控系统的RBC交接为例,使用UML结合可达集计算对系统进行功能安全分析。分析结果表明:UML与可达集计算相结合的方法适用于CTCS-3级列控系统的功能安全分析。