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关键词： MATLAB  

摘要： This study aimed at developing an empirical model for estimating and analyzing CO2 reservoir performance. This was achieved by using decline curve analysis (DCA) to determine an accurate empirical decline model for reservoir performance prediction and optimal producing, i.e., time at which the plant recovery build-up (RBU) efficiency has declined to an approximate value of 44.5%. MATLAB R2013b was used for calculating raw gas density whereas Ms Excel 2007 was used in plotting and performing all calculations. Through an examination of real production data, a harmonic decline model with an Arps’ decline constant (d) of 1.0 and a nominal decline rate of approximately 0.035572337/year was identified as the most suitable for characterizing reservoir performance. The study identifies the year 2048 as an optimal opportunity for implementing production optimization strategies to maximize returns while ensuring efficient resource recovery. Acknowledging the limitations of DCA, the study recommends exploring alternative forecasting models such as type curve analysis (TCA), material balance equation (MBE), and well simulation techniques to mitigate uncertainties in reservoir performance prediction. In addition, the study proposes a 5-year model verification and improvement program to refine reservoir descriptions and enhance data acquisition practices, aiming to optimize production efficiency and minimize uncertainties in CO2 reservoir operations. © The Author(s) 2025.

关键词： Detonation instability   Normal detonation   Cellular structure   Exothermic reaction  

摘要： The distribution of exothermic reaction rates is jointly influenced by reduced activation energy and reaction rate constant. This study focuses on the effect of distribution of exothermic reaction rates on detonation wave propagation instability, specifically under conditions where the length of the induction and exothermic reaction remains constant. It is found that the distribution variation of exothermic reaction rates significantly influences the detonation wave propagation characteristics. Specifically, under conditions of high activation energy, the exothermic reaction rate profile exhibits a smoother distribution but becomes more prone to perturbations. This heightened sensitivity, coupled with the augmented overdriven degree associated with pulsating detonation and cellular detonation wave propagation, further exacerbates the instability characteristics of detonation waves. Especially to the two-dimensional detonation waves with high activation energies, the distribution of exothermic reaction rates becomes more sensitive to these displacements, reinforcing the transverse shock wave and leading to a transformation of the wavefront and cellular structure towards more unstable configurations. This research delves into the intricate interactions between the distribution of exothermic reaction rates and detonation wave instability, aiming to provide an explanatory of detonation instability.

关键词： Boundary-layer transition   Boundary-layer instability   Wind-tunnel experiments   Angle of attack  

摘要： This paper investigates the effect of the angle-of-attack (AOA) on the windward boundary-layer stability over a blunt cone with a nose radius of 5 mm. We consider a free-stream Mach number of 6 and a unit Reynolds number of 4.0 x 107 m-1 and conduct both wind-tunnel experiments and stability analyses for AOAs ranging from 2 degrees-10 degrees at intervals of 2 degrees. The results suggest that, as the AOA increases, the pressure gradient across the spanwise range becomes more pronounced, and the windward-side boundary layer becomes thinner. Using bi-global stability analysis, two unstable three-dimensional modes (varicose and sinuous) are identified in the windward boundary layer at various AOAs. The most unstable mode is the varicose V1 mode, in which the amplitude peak is initially close to the windward centerline and gradually shifts to the centerline downstream. Hence, the primary unstable disturbance exhibits a "V-like" distribution along the streamwise direction, which is likely to cause the V-shaped transition front observed in the wind-tunnel experiments. The eN method based on bi-global analysis is used to predict the transition location along the centerline on the windward region of the cone. The results indicate that, as the AOA increases, the transition location shifts forward, in line with our experimental results. Moreover, linear stability theory accurately predicts the eigenfunction and growth rate of the V1 mode obtained from bi-global analysis. This indicates that linear stability theory can be used to predict transitions in the windward boundary layer of a blunt cone at large AOAs under the conditions studied in this paper.

关键词： Flexoelectricity   Post-buckling   Cylindrical shell   Load-shortening curve   Mode-jumping phenomenon   Size-dependent  

摘要： Unlike the post-buckling behaviors of classical piezoelectric cylindrical shell, the size-dependent effect of flexoelectric material and high strain gradient in the post-buckling process play an important role in the stability analysis of the micro/nano cylindrical shells. To reveal the impacts on the post-buckling of flexoelectric cylindrical shells, an accurate post-buckling model for the flexoelectric cylindrical shells under axial compression is proposed based on the higher-order shear deformation shell theory and von Karman geometrical nonlinearity. The size-dependent post-buckling equilibrium path with mode-jumping phenomena is obtained by using Galerkin's method and Newton-Raphson method. The predicted results are in agreement with those reported in the open literature. A detailed parametric study is also carried out to investigate the influence of geometrical parameters, flexoelectric coefficients, and electric voltage on the size-dependent post-buckling behaviors of flexoelectric cylindrical shells.

ISBN: (纸本)9781009350273

摘要： This textbook introduces the fundamentals of MATLAB for behavioral sciences in a concise and accessible way. Written for those with or without computer programming experience, it works progressively from fundamentals to applied topics, culminating in in-depth projects. Part I covers programming basics, ensuring a firm foundation of knowledge moving forward. Difficult topics, such as data structures and program flow, are then explained with examples from the behavioral sciences. Part II introduces projects for students to apply their learning directly to real-world problems in computational modelling, data analysis, and experiment design, with an exploration of Psychtoolbox. Accompanied by online code and datasets, extension materials, and additional projects, with test banks, lecture slides, and a manual for instructors, this textbook represents a complete toolbox for both students and instructors.

关键词： 血浆凝血因子   慢性肾脏病   孟德尔随机化   因果关系   遗传变异   遗传流行病学   工具变量   单核苷酸多态性   全基因组关联分析   敏感性分析  

摘要： 背景:在许多观察性研究中表明,血浆凝血因子与慢性肾脏病密切相关。尽管如此,血浆凝血因子与慢性肾脏病之间的因果关系仍尚未完全揭示清楚。目的:采用双样本孟德尔随机化方法评估和探讨血浆凝血因子与慢性肾脏病风险之间的关联。方法:从GWAS Catalog数据库中获取不同ID号的39种血浆凝血因子的全基因组关联研究数据,从开放全基因组关联研究数据库(IEU Open GWAS)中获取慢性肾脏病全基因组关联分析数据(ebi-a-GCST003374),其中慢性肾脏病数据集的样本量为117165例,单核苷酸多态性位点数量为2179497个。使用逆方差加权法、MR-Egger回归法、加权中位数法、加权模式法和简单模式法来探讨因果关系;同时,使用CochranQ检验来评估单核苷酸多态性位点的差异性。通过孟德尔随机化-Egger截距测试来验证单核苷酸多态性位点的水平多效性。利用“留一法”进行敏感性分析,以确定孟德尔随机化结果是否会受到单一单核苷酸多态性位点的干扰。结果与结论:(1)通过对39种血浆凝血因子和慢性肾脏病的孟德尔随机化分析,总共发现4种血浆凝血因子与慢性肾脏病相关。血浆凝血因子(FⅤ)水平(OR=0.922,95%CI:0.875-0.971,P=0.002)、血浆FⅦ水平(OR=0.719,95%CI:0.521-0.991,P=0.044)、血浆FⅩa水平(OR=1.113,95%CI:1.009-1.227,P=0.032)、血浆抗凝血Ⅲ水平(OR=0.849,95%CI:0.739-0.975,P=0.020)与慢性肾脏病之间均有显著性意义,P均<0.05;未检测到水平多效性和异质性。(2)基于遗传流行病学方法中双样本孟德尔随机化分析,凝血因子中血浆FⅦ水平、血浆抗凝血酶Ⅲ水平、血浆FⅤ水平是慢性肾脏病发生风险的保护因素,凝血因子中血浆FⅩa水平是慢性肾脏病发生风险的危险因素。(3)上述结果证实,血浆凝血因子与慢性肾脏病之间存在显著的潜在因果关系,虽然文章的数据分析研究的是国际数据库的欧洲人群,但这些数据分析对中国慢性肾脏病与凝血因子的研究有参考价值,对慢性肾脏病的遗传流行病学研究提供了创新的见解,也可为中国相关数据库的深入研究提供一定的参考价值,包括中国健康与养老追踪调查数据库等;未来研究可以重点关注相关凝血因子对慢性肾脏病患者体内低凝或高凝状态的评估。

关键词： Metastatic tumor growth   PDEs   Volterra integral equation   Nystr & ouml   m method  

摘要： In this paper a new MATLAB Toolbox is introduced, Metastatic Tumor Growth Modeling (MTGM). MTGM Toolbox is freely available on a GitHub repository https://***/ IuliaMartinaBulai/MTGM_Toolbox and equips the researchers with five different functionalities. The first one refers to the numerical resolution of a general Volterra Integral Equation (VIE) of the second kind on the positive semiaxis while the last four ones to the computation of biological observables related to metastatic tumor growth models. In particular, the computed observables are the cumulative number of metastases (CNM) and the total metastatic mass (TMM) derived from: (i) a 1D metastatic tumor growth (t.g.) model where the analytical solution of the ODE describing the t.g. law is known, (ii) a 1D model where this solution has to be numerically computed, (iii) a 2D non-autonomous metastatic t.g. model where also the treatment is considered, (iv) a 2D autonomous model, i.e., in the absence of therapies. Moreover, the Toolbox implementation was designed in order to give the users the possibility to extend its functionalities.

关键词： Directed graphs   Programming   Approximation algorithms   Partitioning algorithms   MATLAB   Semi-Definite Programming (SDP)   Lasserre hierarchy   approximation algorithm   Max Cut   Max Bisection  

摘要： We consider the Max Directed 3-Section problem, which is closely connected to other well-known graph partition problems, such as Max Cut and Max Bisection. Given an arc-weighted directed graph, the goal of the Max Directed 3-Section problem is to partition the vertex set into three disjoint subsets with equal size, while maximizing the total weight of arcs crossing different vertex subsets. By combining the Lasserre hierarchy with the random hyperplane rounding strategy, we propose a polynomial-time algorithm with approximation ratio of 0.489.

关键词： 企业党建   人才队伍建设   引领作用   实践  

摘要： 人才队伍建设是企业发展重要任务之一,人才将在各自的工作岗位上发挥作用,共同推进企业发展.企业党建工作的核心任务是将党的理论、政策、方针以及路线等贯彻到企业的各项工作中去.目前,企业党建在人才队伍建设中发挥着思想引领、组织引领、作风引领的作用,因此企业应着重研究企业党建在人才队伍建设中的实践路径,以此最大化发挥企业党建作用与优势.

关键词： 孟德尔随机化   椎间盘退变   肠道菌群   全基因组关联分析   单核苷酸多态性   逆方差加权法   水平多效性   敏感性分析  

摘要： 背景:有研究表明,调节肠道菌群可能会影响椎间盘退变的进程。然而,肠道菌群与椎间盘退变的因果关系尚不清楚。目的:采用孟德尔随机化方法来评估肠道菌群与椎间盘退变之间的潜在因果关系。方法:应用公开发表最新的473种肠道菌群的全基因组关联分析汇总统计数据和芬兰数据库R11中的椎间盘退变的全基因组关联分析汇总数据(椎间盘退变病例46 205例和对照组322 314例)。采用逆方差加权法、MR-Egger回归法、加权中位数法、加权模型法和简单模型法来研究肠道菌群与椎间盘退变之间的因果关系。敏感性分析用于检验孟德尔随机化分析结果是否可靠。反向孟德尔随机化以全部肠道菌群作为结局进行效应分析和敏感性分析。结果与结论:(1)正向孟德尔随机化的逆方差加权法结果显示,毛螺菌目,UBA-6960科、嗜热厌氧杆菌科、盐单胞菌科、丛毛单菌属、戈登氏菌属和欧陆森氏菌属与椎间盘退变呈现正相关。短螺旋体目、假单胞菌目、短螺旋菌科、CAG-776属、螺杆菌属、CAG-448种sp003150135、CAG-776种sp000438195、布劳特氏菌种-A sp000285855和汉逊布劳氏菌种与椎间盘退变呈现负相关。(2)反向孟德尔随机化结果显示,椎间盘退变与玫瑰巴氏菌属、地电细菌属C、弗氏埃希菌种、弗氏丙酸杆菌种、UBA-1777种sp900319835、铜绿假单胞菌种和韦氏芽孢杆菌种呈正相关,与明串珠菌属、普雷沃氏菌种sp000434975、布劳特氏菌种-A sp000285855、CAG-194种sp002441865和CAG-590种sp000431135呈负相关。(3)双向敏感性分析均未发现存在异质性或水平多效性。(4)上述结果说明,基于芬兰数据库探究肠道菌群与椎间盘退变的因果关系,为临床上椎间盘退变的早期预测及治疗探索了新的生物标志物。另外,对于中国生物医学研究,可以借鉴建立大型数据库,整合多中心的医疗数据,为肠道菌群与椎间盘退变关系的研究提供坚实基础,与其他国家的科研团队加强交流与合作,共同推动肠道菌群与疾病关系的研究,为全球医学发展作出贡献。