基于Voronoi建模和Cohesive单元的PBX细观力学模型

针对PBX的细观力学模型存在模型结构与真实PBX细观形貌不符、破坏行为描述不全面(仅考虑界面脱粘)、研究对象单一(大多针对PBX-9501)等问题,建立了基于Voronoi建模和Cohesive单元的PBX细观力学模型。首先,基于光学显微镜下的细观结构图,采用Voronoi方法构建了更贴近实际形貌的PBX炸药细观模型;然后,采用内聚力有限元方法在炸药晶体内部、黏结剂内部及炸药颗粒/黏结剂界面处都引入了Cohesive单元,以在二维尺度上实现任意路径破坏行为的模拟;最后,针对某HMX基-F2311黏结剂炸药和某HMX基-F2313黏结剂炸药标定了模型参数,模拟了这两种炸药的准静态拉伸行为。结果表明,两种炸药数值模拟的拉伸变形曲线、破坏应力、破坏应变都与试验数据吻合良好,表明该模型不仅适用于不同PBX炸药材料(线弹性PBX、非线性PBX)的变形行为描述,还可以分析PBX炸药在拉伸破坏过程中的细观机理,刻画不同PBX炸药的裂纹萌生、扩展和贯穿的过程。

Relationship between family cohesion/adaptability and postpartum depressive symptoms:A single-center retrospective study

BACKGROUND Depression is the most common mental illness in postpartum mothers,and the etiology of postpartum depression remains poorly understood.Over the past several decades,studies have reported that postpartum depression is caused by multiple factors,such as genetic,psychological,pregnancy,and environmental factors,with the family environment being an important environmental factor.The theory of family cohesion and adaptability put forward by Olson is a classic model that describes the level of family function.However,to date,this model has not been examined regarding its applicability to patients with postpartum depression.AIM To investigate the relationship between family cohesion and adaptability and the risk of postpartum depressive symptoms.METHODS We retrospectively analyzed 1446 patients admitted to the postpartum healthcare clinic of the Affiliated Foshan Maternity and Child Healthcare Hospital from April 2021 to December 2021.Patients were grouped according to whether postpartum depression symptoms were reported(symptoms,n=454;no symptoms,n=992).All patients completed the Edinburgh Postpartum Depression Scale and the Chinese version of the Family Cohesion and Adaptability Assessment Scale II.Baseline and clinical data were compared between groups.Univariate regression analysis was used to investigate the association between different types of family cohesion and postpartum depressive symptoms and the association between different family adaptability types and postpartum depressive symptoms.RESULTS After adjusting for age,education,occupation,gravidity,parity,and mode of delivery,disengaged[adjusted odds ratio(AOR)=3.36,95%CI:1.91-5.91],and separated(AOR=1.97,95%CI:1.34-2.90)family cohesion types showed a higher risk of postpartum depression than the connection type,whereas the enmeshed type(AOR=0.38,95%CI:0.28-0.51)protected against postpartum depressive symptoms.Rigid(AOR=4.41,95%CI:3.02-6.43)and structured families(AOR=1.88,95%CI:1.34-2.63)had a higher risk of postpartum depressive symptoms than flexible families,whereas chaotic families(AOR=0.35,95%CI:0.24-0.51)protected against postpartum depressive symptoms.CONCLUSION Family cohesion and adaptability are influencing factors for postpartum depressive symptoms,with higher family cohesion and adaptability being associated with a lower risk of postpartum depressive symptoms.

Effect of Family Cohesion on Depression of Chinese College Students in the COVID-19 Pandemic: Chain Mediation Effect of Perceived Social Support and Intentional Self-Regulation

Individuals’perceptions,attitudes,and patterns of getting along with family members are important factors influencing Chinese people’s self-evaluation.The aim of this study was to investigate the effect of family cohesion on depression and the role of perceived social support and intentional self-regulation in this association.A hypothesized model of the association of family cohesion,perceived social support,intentional self-regulation,and depression was examined.A convenience sampling method was used to survey 1,180 college students in Yunnan Province using self-report.Data were collected using the Family Cohesion Scale,the Perceived Social Support Scale,the Intentional Self-Regulation Scale,and the Center for Epidemiological Studies Depression Scale.The findings revealed low to moderate correlation between the variables studied.College students’family cohesion was a negative predictor of their depression.This association was also mediated by the knock-on effect of perceived social support and intentional self-regulation.These findings show how family cohesion affects college students’depressive status.Specifically,these results help demonstrate the importance of family cohesion,perceived social support,and intentional self-regulation in optimizing students’depression,which in turn can promote better psychological states.

A Component Selection Framework of Cohesion and Coupling Metrics

Component-based software engineering is concerned with the develop-ment of software that can satisfy the customer prerequisites through reuse or inde-pendent development.Coupling and cohesion measurements are primarily used to analyse the better software design quality,increase the reliability and reduced system software complexity.The complexity measurement of cohesion and coupling component to analyze the relationship between the component module.In this paper,proposed the component selection framework of Hexa-oval optimization algorithm for selecting the suitable components from the repository.It measures the interface density modules of coupling and cohesion in a modular software sys-tem.This cohesion measurement has been taken into two parameters for analyz-ing the result of complexity,with the help of low cohesion and high cohesion.In coupling measures between the component of inside parameters and outside parameters.Thefinal process of coupling and cohesion,the measured values were used for the average calculation of components parameter.This paper measures the complexity of direct and indirect interaction among the component as well as the proposed algorithm selecting the optimal component for the repository.The better result is observed for high cohesion and low coupling in compo-nent-based software engineering.

Software Coupling and Cohesion Model for Measuring the Quality of Software Components

Measuring software quality requires software engineers to understand the system’s quality attributes and their measurements.The quality attribute is a qualitative property;however,the quantitative feature is needed for software measurement,which is not considered during the development of most software systems.Many research studies have investigated different approaches for measuring software quality,but with no practical approaches to quantify and measure quality attributes.This paper proposes a software quality measurement model,based on a software interconnection model,to measure the quality of software components and the overall quality of the software system.Unlike most of the existing approaches,the proposed approach can be applied at the early stages of software development,to different architectural design models,and at different levels of system decomposition.This article introduces a software measurement model that uses a heuristic normalization of the software’s internal quality attributes,i.e.,coupling and cohesion,for software quality measurement.In this model,the quality of a software component is measured based on its internal strength and the coupling it exhibits with other component(s).The proposed model has been experimented with nine software engineering teams that have agreed to participate in the experiment during the development of their different software systems.The experiments have shown that coupling reduces the internal strength of the coupled components by the amount of coupling they exhibit,which degrades their quality and the overall quality of the software system.The introduced model can help in understanding the quality of software design.In addition,it identifies the locations in software design that exhibit unnecessary couplings that degrade the quality of the software systems,which can be eliminated.

Finite Element Simulations of the Localized Failure and Fracture Propagation in Cohesive Materials with Friction

Strain localization frequently occurs in cohesive materials with friction(e.g.,composites,soils,rocks)and is widely recognized as a fundamental cause of progressive structural failure.Nonetheless,achieving high-fidelity simulation for this issue,particularly concerning strong discontinuities and tension-compression-shear behaviors within localized zones,remains significantly constrained.In response,this study introduces an integrated algorithmwithin the finite element framework,merging a coupled cohesive zone model(CZM)with the nonlinear augmented finite elementmethod(N-AFEM).The coupledCZMcomprehensively describes tension-compression and compressionshear failure behaviors in cohesive,frictional materials,while the N-AFEM allows nonlinear coupled intraelement discontinuities without necessitating extra nodes or nodal DoFs.Following CZM validation using existing experimental data,this integrated algorithm was utilized to analyze soil slope failure mechanisms involving a specific tensile strength and to assess the impact of mechanical parameters(e.g.,tensile strength,weighting factor,modulus)in soils.

Investigation of FRP and SFRC Technologies for Efficient Tunnel Reinforcement Using the Cohesive Zone Model

Amid urbanization and the continuous expansion of transportation networks,the necessity for tunnel construction and maintenance has become paramount.Addressing this need requires the investigation of efficient,economical,and robust tunnel reinforcement techniques.This paper explores fiber reinforced polymer(FRP)and steel fiber reinforced concrete(SFRC)technologies,which have emerged as viable solutions for enhancing tunnel structures.FRP is celebrated for its lightweight and high-strength attributes,effectively augmenting load-bearing capacity and seismic resistance,while SFRC’s notable crack resistance and longevity potentially enhance the performance of tunnel segments.Nonetheless,current research predominantly focuses on experimental analysis,lacking comprehensive theoretical models.To bridge this gap,the cohesive zone model(CZM),which utilizes cohesive elements to characterize the potential fracture surfaces of concrete/SFRC,the rebar-concrete interface,and the FRP-concrete interface,was employed.A modeling approach was subsequently proposed to construct a tunnel segment model reinforced with either SFRC or FRP.Moreover,the corresponding mixed-mode constitutive models,considering interfacial friction,were integrated into the proposed model.Experimental validation and numerical simulations corroborated the accuracy of the proposed model.Additionally,this study examined the reinforcement design of tunnel segments.Through a numerical evaluation,the effectiveness of innovative reinforcement schemes,such as substituting concrete with SFRC and externally bonding FRP sheets,was assessed utilizing a case study from the Fuzhou Metro Shield Tunnel Construction Project.

Extended finite element-based cohesive zone method for modeling simultaneous hydraulic fracture height growth in layered reservoirs

In this study,a fully coupled hydromechanical model within the extended finite element method(XFEM)-based cohesive zone method(CZM)is employed to investigate the simultaneous height growth behavior of multi-cluster hydraulic fractures in layered porous reservoirs with modulus contrast.The coupled hydromechanical model is first verified against an analytical solution and a laboratory experiment.Then,the fracture geometry(e.g.height,aperture,and area)and fluid pressure evolutions of multiple hydraulic fractures placed in a porous reservoir interbedded with alternating stiff and soft layers are investigated using the model.The stress and pore pressure distributions within the layered reservoir during fluid injection are also presented.The simulation results reveal that stress umbrellas are easily to form among multiple hydraulic fractures’tips when propagating in soft layers,which impedes the simultaneous height growth.It is also observed that the impediment effect of soft layer is much more significant in the fractures suppressed by the preferential growth of adjoining fractures.After that,the combined effect of in situ stress ratio and fracturing spacing on the multi-fracture height growth is presented,and the results elucidate the influence of in situ stress ratio on the height growth behavior depending on the fracture spacing.Finally,it is found that the inclusion of soft layers changes the aperture distribution of outmost and interior hydraulic fractures.The results obtained from this study may provide some insights on the understanding of hydraulic fracture height containment observed in filed.

Effect of slice scope on data slice-based class cohesion metrics

This paper suggests that a single class rather than methods should be used as the slice scope to compute class cohesion. First, for a given attribute, the statements in all methods that last define the attribute are computed. Then, the forward and backward data slices for this attribute are generated by using the class as the slice scope and are combined to compute the corresponding class data slice. Finally, the class cohesion is computed based on all class data slices for the attributes. Compared to traditional cohesion metrics that use methods as the slice scope, the proposed metrics that use a single class as slice scope take into account the possible interactions between the methods. The experimental results show that class cohesion can be more accurately measured when using the class as the slice scope.

Study on the Development of Urban Cohesion

Urban cohesion is a new development phenomenon of urbanization, requires further study in both practices and theories. In this study, the connotation, development premise and existing problems of urbanization have been primarily explored, to obtain useful ideas.

阐释《建设学习型城市北京宣言》的第一承诺——“Empowering Individuals and Promoting Social Cohesion”的意涵和践履

2013年10月"首届国际学习型城市大会"在北京隆重召开。102个国家的500多名代表一致通过了《建设学习型城市北京宣言》。其中有十二项承诺,而第一承诺便是"Empowering Individuals and Promoting Social Cohesion"(促进个体赋权增能和增强社会凝聚)。何谓"赋权增能"和"社会凝聚"不能从简单的汉译来理解,需从词源来准确辨析,更需要从政治学、社会学、法学、心理学等角度领略其深刻的内涵。"赋权增能"与"社会凝聚"有密切的内在联系,其指向目标、目的、效能等核心价值构成完整体系。学习型城市建设与"赋权增能"和"社会凝聚"有着高度的重要关联。在改革开放的今天,践履"第一承诺"已经成为我国唯一选择。怎样践履这一庄严承诺,《北京宣言》指出了基本路向,在表达教育机会、基本能力、社会参与、性别平等、贫富差距、社区建设等兑现承诺的特定语境中,充分揭示了《北京宣言》将"赋权增能"、"社会凝聚"作为第一承诺的理由和重要意义。这应是对《北京宣言》第一承诺的完整理解。

基于JKR-Cohesion模型的湿颗粒松散堆积体滑坡模拟分析

为深入研究湿颗粒松散堆积体滑坡的运动特征,提出采用JKR-Cohesion模型模拟湿颗粒堆积体的运动行为。基于离散单元法(DEM)建立了三维松散堆积体滑坡水槽模型,模拟堆积体整个运移过程,并将计算结果与干燥颗粒堆积体运动结果进行对比。计算结果表明:湿颗粒松散堆积体的运动受水的粘附力影响很大,相对于干燥颗粒,运动速度最大值更小,运动时间更短,且大部分颗粒堆积在坡面上;湿颗粒堆积体在运动过程中解体为小团体单独运动,而干燥颗粒运动连续性好,运动距离更远。提出的方法对于含水堆土的滑坡模拟有一定借鉴作用。

Lexis Cohesion and English Reading

This article discusses one of the important cohesion means—lexis cohesion, and applies it to English reading. This cohesion contributes to the improvement of reading ability for its immediateness and accessibility. It aims at specifying the potentials of the theory in English reading learning by analysis and exemplification.

浅议英语中的cohesion和coherence

衔接与连贯是语篇研究中的重要概念 ,它们是两个彼此不同而又相互关联的术语。衔接与连贯实现的途径不同。从广义衔接和狭义衔接两方面探讨了衔接实现的途径 ,从语境和语用两方面探讨了连贯的实现手段 ,从而提出衔接与连贯的划分标准。

On Reference and Cohesion

In the study of textlinguistics,cohesion is one important subject. According Halliday and Hasan,cohesion can be achieved through two ways. One is lexical cohesion and the other is grammatical cohesion. Reference is one of the most important devices in grammatical cohesion. It can be divided into personal reference,demonstrative reference,and comparative reference. Some of these references can be used as cataphora,some can be used as anaphora and some can be used as both. Analysis and explanation as well as examples are provided in this paper to facilitate the reader's understanding and use of reference.

The System of Reference and Lexical Cohesion in Newspaper-An Example of Analyzing "Beijing and Shanghai in Race to Attract Top Foreign Talents"

Discourse analysis is gaining its prominence in teaching reading. The paper presents an example of analyzing the system of reference and lexical cohesion of a news report. It demonstrates how to involve discourse analysis into the teaching of newspaper reading in order to make students get a clear framework of reference and lexical cohesion in a functional-grammar-conscious manner.

Cohesion in Writing of EFL Learners

Cohesion tends to be denser and more noticeable in written discourse than in spoken discourse. A text will become problematic or is not easy to make sense to readers if any cohesion is troubled. The present paper is going to investigate cohesion in Chinese advanced learners' expository writing by comparing and analyzing the cohesive ties in two student writers' essays.

On Cohesion of I have a Dream

Cohesion theory was proposed by Halliday and Hasan in 1976,and then developed by them in 1985.Through the analysis of cohesive devices of the famous speech I have a Dream from the aspects of grammatical cohesion,lexical cohesion and parallelism,this paper proves that it not only functions as a device to make the text more compact,but could make the text more expressive and persuasive.

基于Linear Cohesion模型的含水堆积体滑坡过程数值模拟

水通常是堆积体滑坡发生的触发因素,采用数值方法模拟堆积体滑坡时加入水的液桥力有助于提高计算结果的合理性。为了研究含水堆积体滑坡过程的各项运动特性,提出采用Linear Cohesion接触模型模拟含水湿润状态下松散堆积体滑坡的运动过程,利用离散元程序EDEM 2017建立了含水堆积体滑坡水槽数值模型,计算堆积体从失稳-滑动-堆积整个运动过程。结果表明:能量密度k是Linear Cohesion模型模拟含水堆积体滑坡的关键参数;当k<5000 J/m^3时,随着能量密度值逐渐增大,堆积体滑动过程的流动性越来越小,最大平均速度值和最大动能越大,当k≥5000 J/m^3时,含水堆积体的各项滑动特征变化不明显;较小能量密度的湿颗粒堆积体在滑动过程中结构体易发生破坏,形成的颗粒群流动性更强,滑动距离更远,扩大了滑坡灾害的影响范围。相关研究成果对今后类似的含水堆积体滑坡灾害的预测和评估有一定参考价值。

The Application of “Cohesion” in C-E Translation

This paper deals with the theory of cohesion, the importance of the "cohesion"criterion in C-E translation and the ways of producing a cohesive translation.