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A concise review about fracture assessments of brittle solids with V-notches

Hsien-Yang YEH, Bin YANG

《结构与土木工程前沿（英文）》 2019年 第13卷 第2期   页码 478-485 doi: 10.1007/s11709-019-0520-z

摘要：

A concise review of recent studies about the fracture assessments of elastic brittle solid materials containing V-notches is presented. In this preliminary and brief survey, elastic stress distributions in V-notched solids are discussed first. The concept of notch stress intensity factor is introduced. Combine the digital image correlation method with numerical computation techniques to analyze the stress distribution near the notches. Fracture criteria such as strain energy density, J-integral, theory of critical distance are used.

关键词： fracture     assessment     brittle solids     V-notches     review    

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A review on ductile mode cutting of brittle materials

Elijah Kwabena ANTWI, Kui LIU, Hao WANG

《机械工程前沿（英文）》 2018年 第13卷 第2期   页码 251-263 doi: 10.1007/s11465-018-0504-z

摘要：

Brittle materials have been widely employed for industrial applications due to their excellent mecha-nical, optical, physical and chemical properties. But obtaining smooth and damage-free surface on brittle materials by traditional machining methods like grinding, lapping and polishing is very costly and extremely time consuming. Ductile mode cutting is a very promising way to achieve high quality and crack-free surfaces of brittle materials. Thus the study of ductile mode cutting of brittle materials has been attracting more and more efforts. This paper provides an overview of ductile mode cutting of brittle materials including ductile nature and plasticity of brittle materials, cutting mechanism, cutting characteristics, molecular dynamic simulation, critical undeformed chip thickness, brittle-ductile transition, subsurface damage, as well as a detailed discussion of ductile mode cutting enhancement. It is believed that ductile mode cutting of brittle materials could be achieved when both crack-free and no subsurface damage are obtained simultaneously.

关键词： ductile mode cutting     brittle materials     critical undeformed chip thickness     brittle-ductile transition     subsurface damage     molecular dynamic simulation    

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A FEniCS implementation of the phase field method for quasi-static brittle fracture

HIRSHIKESH, Sundararajan NATARAJAN, Ratna Kumar ANNABATTULA

《结构与土木工程前沿（英文）》 2019年 第13卷 第2期   页码 380-396 doi: 10.1007/s11709-018-0471-9

摘要： In the recent years, the phase field method for simulating fracture problems has received considerable attention. This is due to the salient features of the method: 1) it can be incorporated into any conventional finite element software; 2) has a scalar damage variable is used to represent the discontinuous surface implicitly and 3) the crack initiation and subsequent propagation and branching are treated with less complexity. Within this framework, the linear momentum equations are coupled with the diffusion type equation, which describes the evolution of the damage variable. The coupled nonlinear system of partial differential equations are solved in a ‘staggered’ approach. The present work discusses the implementation of the phase field method for brittle fracture within the open-source finite element software, FEniCS. The FEniCS provides a framework for the automated solutions of the partial differential equations. The details of the implementation which forms the core of the analysis are presented. The implementation is validated by solving a few benchmark problems and comparing the results with the open literature.

关键词： phase field method     FEniCS     brittle fracture     crack propagation     variational theory of fracture    

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Advances in molecular dynamics simulation of ultra-precision machining of hard and brittle materials

Xiaoguang GUO,Qiang LI,Tao LIU,Renke KANG,Zhuji JIN,Dongming GUO

《机械工程前沿（英文）》 2017年 第12卷 第1期   页码 89-98 doi: 10.1007/s11465-017-0412-7

摘要：

Hard and brittle materials, such as silicon, SiC, and optical glasses, are widely used in aerospace, military, integrated circuit, and other fields because of their excellent physical and chemical properties. However, these materials display poor machinability because of their hard and brittle properties. Damages such as surface micro-crack and subsurface damage often occur during machining of hard and brittle materials. Ultra-precision machining is widely used in processing hard and brittle materials to obtain nanoscale machining quality. However, the theoretical mechanism underlying this method remains unclear. This paper provides a review of present research on the molecular dynamics simulation of ultra-precision machining of hard and brittle materials. The future trends in this field are also discussed.

关键词： MD simulation     ultra-precision machining     hard and brittle materials     machining mechanism     review    

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Research progress on ultra-precision machining technologies for soft-brittle crystal materials

Hang GAO,Xu WANG,Dongming GUO,Yuchuan CHEN

《机械工程前沿（英文）》 2017年 第12卷 第1期   页码 77-88 doi: 10.1007/s11465-017-0411-8

摘要：

Soft-brittle crystal materials are widely used in many fields, especially optics and microelectronics. However, these materials are difficult to machine through traditional machining methods because of their brittle, soft, and anisotropic nature. In this article, the characteristics and machining difficulties of soft-brittle and crystals are presented. Moreover, the latest research progress of novel machining technologies and their applications for soft-brittle crystals are introduced by using some representative materials (e.g., potassium dihydrogen phosphate (KDP), cadmium zinc telluride (CZT)) as examples. This article reviews the research progress of soft-brittle crystals processing.

关键词： brittle     soft     functional crystal     ultra-precision machining    

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High-gravity-assisted emulsification for continuous preparation of waterborne polyurethane nanodispersion with high solids

Weihong Zhang, Dan Wang, Jie-Xin Wang, Yuan Pu, Jian-Feng Chen

《化学科学与工程前沿（英文）》 2020年 第14卷 第6期   页码 1087-1099 doi: 10.1007/s11705-019-1895-z

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Modeling of solids segregation in circulating fluidized bed boilers

Xuan YAO, Tao WANG, Jia ZHAO, Hairui YANG, Hai ZHANG

《能源前沿（英文）》 2011年 第5卷 第1期   页码 115-119 doi: 10.1007/s11708-010-0103-0

摘要： Segregation always occurs in a circulating fluidized bed (CFB) because of the wide distribution of particle size and density of the bed material. Terminal velocity has a significant influence on solids segregation; thus, it is convenient to describe the segregation tendency using single particle terminal velocity . This paper proposes a segregation model in CFB boilers based on the Cell Model. In each cell along the riser, varied-sized particles have different tendencies toward segregation; finer particles are carried out more easily, while coarser ones tend to sink into the cell. It is assumed that the average terminal velocity , corresponding to the mean particle size in the cell, has a segregation index of = 1.0 as the reference point. The segregation index of particles with higher terminal velocity is lower than 1.0, while that for finer particles is larger than 1.0. The empirical formulae of segregation parameters, namely and , are derived by optimizing experimental data in published literature. The test result of ash size distribution in a 220 t/h CFB boiler validates the reasonableness of the model.

关键词： segregation     model     terminal velocity     circulating fluidized bed (CFB)    

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Implementation aspects of a phase-field approach for brittle fracture

G. D. HUYNH, X. ZHUANG, H. NGUYEN-XUAN

《结构与土木工程前沿（英文）》 2019年 第13卷 第2期   页码 417-428 doi: 10.1007/s11709-018-0477-3

摘要： This paper provides a comprehensive overview of a phase-field model of fracture in solid mechanics setting. We start reviewing the potential energy governing the whole process of fracture including crack initiation, branching or merging. Then, a discretization of system of equation is derived, in which the key aspect is that for the correctness of fracture phenomena, a split into tensile and compressive terms of the strain energy is performed, which allows crack to occur in tension, not in compression. For numerical analysis, standard finite element shape functions are used for both primary fields including displacements and phase field. A staggered scheme which solves the two fields of the problem separately is utilized for solution step and illustrated with a segment of Python code.

关键词： phase-field modeling     FEM     staggered scheme     fracture    

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Impact of solids on biphasic biodegradation of phenanthrene in the presence of hydroxypropyl- β

Zhenyi ZHANG, Chihiro INOUE, Guanghe LI,

《环境科学与工程前沿（英文）》 2010年 第4卷 第3期   页码 329-333 doi: 10.1007/s11783-010-0232-z

摘要： The consequence of polycyclic aromatic hydrocarbons (PAHs) in the environment is of great concern. The hydrophobic properties of PAHs significantly impact phase distribution causing limited bioavailability. Enhanced biodegradation has been extensively carried out by surfactants and the redeployment effect was recognized. However, the quantitative relationship concerning the impact of solids was rarely reported. A batch of biphasic tests were carried out by introducing PYR-1 and hydroxypropyl--cyclodextrin (HPCD) into a mixture of phenanthrene solution and various glass beads (GB37-63, GB105-125, and GB350-500). The comparative results demonstrated that HPCD had little effect on microbial growth and was not degradable by bacterium. A model was proposed to describe the biodegradation process. The regression results indicated that the partition coefficient (1.234, 0.726 and 0.448 L·g) and the degradation rate (0 mmol·L: 0.055, 0.094, and 0.112; 20 mmol·L: 0.126, 0.141, and 0.156; 40 mmol·L: 0.141, 0.156 and 0.184 d) were positively and negatively correlated with the calculated total surface area (TSA) of solids, respectively. Degradation enhanced in the presence of HPCD, and the enhancing factor was calculated (20 mmol·L: 15.16, 40.01, and 145.5; 40 mmol·L: 13.29, 37.97, and 138.4), indicating that the impact of solids was significant for the enhancement of biodegradation.

关键词： biphasic biodegradation     hydroxypropyl-β     -cyclodextrin (HPCD)     polycyclic aromatic hydrocarbons (PAHs)    

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Gas-solids separation model of a novel FCC riser terminator device: super short quick separator (SSQS

LU Chunxi, LI Ruxin, SHI Mingxian, LIU Xiancheng

《化学科学与工程前沿（英文）》 2008年 第2卷 第4期   页码 462-467 doi: 10.1007/s11705-008-0068-2

摘要： The gas flow field and the separation efficiency of a novel fluid catalytic cracking (FCC) riser terminal device, named as Super Short Quick Separator (SSQS), were studied. On the basis of above investigations, a section-lateral-mixing separation model was proposed, which included both the effect of inertia and structure of gas outlet on particles capture. After final modification, the results predicted with this model could be in good agreement with the cold experimental data. According to this model, the separation efficiency of SSQS is mainly influenced by the difference between the arc radius and the center pipe radius as well as the magnitude of particle tangential velocity.

关键词： catalytic cracking     separation efficiency     tangential velocity     agreement     magnitude    

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6G移动网络架构SOLIDS——驱动力、特征及功能拓扑 Review

刘光毅, 李娜, 邓娟, 王莹莹, 孙军帅, 黄宇红

《工程（英文）》 2022年 第8卷 第1期   页码 42-59 doi: 10.1016/j.eng.2021.07.013

摘要： 所提6G网络架构称为SOLIDS，由其六大基本网络特征构成，即柔性（soft）、按需服务（on-demand fulfillment）、至简（lite）、内生智慧（native intelligence

关键词： 第六代     网络特征     网络架构    

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Semi-solid materials for controlled release drug formulation: current status and future prospects

Michelle TRAN,Chun WANG

《化学科学与工程前沿（英文）》 2014年 第8卷 第2期   页码 225-232 doi: 10.1007/s11705-014-1429-7

摘要： Semi-solid materials represent an important category of inactive ingredients (excipients) of pharmaceutical products. Here we review several common semi-solid polymers currently used in the controlled release formulations of many drugs. These polymers are selected based on their importance and broad scope of application in FDA-approved drug products and include several polysaccharides (cellulose, starch, chitosan, alginate) and carbomers, a group of mucoadhesive synthetic polymers. Glyceride-based polymers used in self-emulsifying drug delivery systems (SEDDS) will also be discussed for its importance in formulating poorly water-soluble drugs. Unique features and advantages of each type of semi-solid materials are discussed and examples of their use in oral delivery of drugs are provided. Finally, future prospects of developing new and better semi-solid excipients are discussed with the objective of facilitating clinical translation.

关键词： controlled release     drug delivery     semi-solids     polymer     excipient    

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Evaluation of groundwater quality in the Xinjiang Plain Area

Jinlong ZHOU, Xinguang DONG, Yiping WANG, Guomin LI, Xiaojing GUO,

《环境科学与工程前沿（英文）》 2010年 第4卷 第2期   页码 183-186 doi: 10.1007/s11783-010-0021-8

摘要： Groundwater is the main source of drinking water for the urban and rural residents in the plain area of the Xinjiang Uygur Autonomous Region, China. The quality of groundwater has a direct relationship with human health. Thus, 386 groundwater samples collected from April to August in 2003 were analyzed. The samples were collected in basic evaluation units which are determined on the basis of watersheds. Total dissolved solids, total hardness, pH value, NH–N, CHOH, Chemiluminescence detection of permanganate index (COD) and intestinal germ group were evaluated according to the guidelines of Groundwater Quality Standard (GB/T14848-93). The quality of the groundwater in each evaluation unit was classified by using the One Veto Method (a unified approach stipulated by the Ministry of Water Resources). The results indicate that the groundwater in the mainstream area of the Tarim Basin and the Yerqiang River Sub-basin belongs to Category V; the groundwater in the Wulungu River Sub-basin, the Kaidu-Kongque River Sub-basin, the Kashgar River Sub-basin, the Cherchen River Sub-basin and the Hotan River Sub-basin belongs to Category IV; the groundwater in the Aibi Lake System belongs to Category II, and the groundwater of other evaluation units belongs to Category III. The causes of water quality formation were concisely analyzed. The results can be useful for the evaluation and management of water resources in the Xinjiang Plain Area.

关键词： groundwater quality     evaluation     one veto method     total dissolved solids (TDS)     pH     total hardness    

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Effectiveness of aerobic pretreatment of municipal solid waste for accelerating biogas generation during simulated landfilling

Munawar Ali, Junli Zhang, Roberto Raga, Maria Cristina Lavagnolo, Alberto Pivato, Xu Wang, Yuanyuan Zhang, Raffaello Cossu, Dongbei Yue

《环境科学与工程前沿（英文）》 2018年 第12卷 第3期 doi: 10.1007/s11783-018-1031-1

摘要： This study evaluates the effectiveness of aerobic pretreatment of municipal solid waste (MSW) on reducing lag phase and accelerating biogas generation. Aerobic pretreatment degree (APD) was determined on the basis of reduction in volatile solids (VS) on a wet weight basis. In this study, intermittent aeration (IA) was applied to three reactors as a main aeration mode; since a single reactor was operated under continuous aeration mode. However, the purpose of the experiment was to reduce VS content of waste, irrespective of the comparison between aeration modes. Fresh MSW was first pretreated aerobically with different aeration rates (10, 40, 60 and 85 L/min/m ) for the period of 30–50 days, resulting in VS-loss equivalent to 20%, 27%, 38% and 53% on w/w basis for the wastes A1, A2, A3 and A4, respectively. The cumulative biogas production, calculated based on the modified Gompertz model were 384, 195, 353, 215, and 114 L/kg VS for the wastes A0, A1, A2, A3 and A4, respectively. Untreated waste (A0) showed a long lag phase; whereas the lag phases of pretreated MSW were reduced by more than 90%. Aerobically pretreated wastes reached stable methanogenic phase within 41 days compared to 418 days for untreated waste. The waste mass decreased by about 8% to 27% compared to untreated MSW, indicative that even more MSW could be placed in the same landfill. The study confirmed the effectiveness of aerobic pretreatment of MSW prior to landfilling on reducing lag phase and accelerating biogas generation.

关键词： Municipal solid waste (MSW)     Aerobic pretreatment degree (APD)     Volatile solids (VS)     Intermittent aeration (IA)     Landfill gas     Landfilling    

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标题 作者 时间 类型 操作

A concise review about fracture assessments of brittle solids with V-notches

Hsien-Yang YEH, Bin YANG

期刊论文

A review on ductile mode cutting of brittle materials

Elijah Kwabena ANTWI, Kui LIU, Hao WANG

期刊论文

A FEniCS implementation of the phase field method for quasi-static brittle fracture

HIRSHIKESH, Sundararajan NATARAJAN, Ratna Kumar ANNABATTULA

期刊论文

Advances in molecular dynamics simulation of ultra-precision machining of hard and brittle materials

Xiaoguang GUO,Qiang LI,Tao LIU,Renke KANG,Zhuji JIN,Dongming GUO

期刊论文

Research progress on ultra-precision machining technologies for soft-brittle crystal materials

Hang GAO,Xu WANG,Dongming GUO,Yuchuan CHEN

期刊论文

High-gravity-assisted emulsification for continuous preparation of waterborne polyurethane nanodispersion with high solids

Weihong Zhang, Dan Wang, Jie-Xin Wang, Yuan Pu, Jian-Feng Chen

期刊论文

Modeling of solids segregation in circulating fluidized bed boilers

Xuan YAO, Tao WANG, Jia ZHAO, Hairui YANG, Hai ZHANG

期刊论文

Implementation aspects of a phase-field approach for brittle fracture

G. D. HUYNH, X. ZHUANG, H. NGUYEN-XUAN

期刊论文

Impact of solids on biphasic biodegradation of phenanthrene in the presence of hydroxypropyl- β

Zhenyi ZHANG, Chihiro INOUE, Guanghe LI,

期刊论文

Gas-solids separation model of a novel FCC riser terminator device: super short quick separator (SSQS

LU Chunxi, LI Ruxin, SHI Mingxian, LIU Xiancheng

期刊论文

6G移动网络架构SOLIDS——驱动力、特征及功能拓扑

刘光毅, 李娜, 邓娟, 王莹莹, 孙军帅, 黄宇红

期刊论文

Semi-solid materials for controlled release drug formulation: current status and future prospects

Michelle TRAN,Chun WANG

期刊论文

Evaluation of groundwater quality in the Xinjiang Plain Area

Jinlong ZHOU, Xinguang DONG, Yiping WANG, Guomin LI, Xiaojing GUO,

期刊论文

Effectiveness of aerobic pretreatment of municipal solid waste for accelerating biogas generation during simulated landfilling

Munawar Ali, Junli Zhang, Roberto Raga, Maria Cristina Lavagnolo, Alberto Pivato, Xu Wang, Yuanyuan Zhang, Raffaello Cossu, Dongbei Yue

期刊论文

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2021年04月22日

会议视频