资源类型

期刊论文 798

会议视频 32

年份

2024 1

2023 46

2022 95

2021 63

2020 56

2019 48

2018 37

2017 57

2016 29

2015 36

2014 36

2013 30

2012 29

2011 30

2010 25

2009 35

2008 34

2007 50

2006 23

2005 14

展开 ︾

关键词

仿真 7

农业科学 6

质量控制 6

控制 5

智能控制 4

能源 4

主动控制 3

模糊控制 3

环境 3

神经网络 3

自适应控制 3

解耦控制 3

风险控制 3

2021全球十大工程成就 2

2022全球工程前沿 2

三峡升船机 2

三峡工程 2

不确定性 2

中药 2

展开 ︾

检索范围：

排序： 展示方式：

Reliability mesh convergence analysis by introducing expanded control variates

Alireza GHAVIDEL, Mohsen RASHKI, Hamed GHOHANI ARAB, Mehdi AZHDARY MOGHADDAM

《结构与土木工程前沿（英文）》 2020年 第14卷 第4期   页码 1012-1023 doi: 10.1007/s11709-020-0631-6

摘要： The safety evaluation of engineering systems whose performance evaluation requires finite element analysis is a challenge in reliability theory. Recently, Adjusted Control Variates Technique (ACVAT) has proposed by the authors to solve this issue. ACVAT uses the results of a finite element method (FEM) model with coarse mesh density as the control variates of the model with fine mesh and efficiently solves FEM-based reliability problems. ACVAT however does not provide any results about the reliability-based mesh convergence of the problem, which is an important tool in FEM. Mesh-refinement analysis allows checking whether the numerical solution is sufficiently accurate, even though the exact solution is unknown. In this study, by introducing expanded control variates (ECV) formulation, ACVAT is improved and the capabilities of the method are also extended for efficient reliability mesh convergence analysis of FEM-based reliability problems. In the present study, the FEM-based reliability analyses of four practical engineering problems are investigated by this method and the corresponding results are compared with accurate results obtained by analytical solutions for two problems. The results confirm that the proposed approach not only handles the mesh refinement progress with the required accuracy, but it also reduces considerably the computational cost of FEM-based reliability problems.

关键词： finite element     reliability mesh convergence analysis     expanded control variates    

HTML PDF 收藏

Flow and thermal modeling of liquid metal in expanded microchannel heat sink

《能源前沿（英文）》   页码 796-810 doi: 10.1007/s11708-023-0877-5

摘要： Liquid metal-based microchannel heat sinks (MCHSs) suffer from the low heat capacity of coolant, resulting in an excessive temperature rise of coolant and heat sink when dealing with high-power heat dissipation. In this paper, it was found that expanded space at the top of fins could distribute the heat inside microchannels, reducing the temperature rise of coolant and heat sink. The orthogonal experiments revealed that expanding the top space of channels yielded similar temperature reductions to changing the channel width. The flow and thermal modeling of expanded microchannel heat sink (E-MCHS) were analyzed by both using the 3-dimensional (3D) numerical simulation and the 1-dimensional (1D) thermal resistance model. The fin efficiency of E-MCHS was derived to improve the accuracy of the 1D thermal resistance model. The heat conduction of liquid metal in Z direction and the heat convection between the top surface of fins and the liquid metal could reduce the total thermal resistance (Rt). The above process was effective for microchannels with low channel aspect ratio, low mean velocity (Um) or long heat sink length. The maximum thermal resistance reduction in the example of this paper reached 36.0%. The expanded space endowed the heat sink with lower pressure, which might further reduce the pumping power (P). This rule was feasible both when fins were truncated (h2 < 0, h2 is the height of expanded channel for E-MCHS) and when over plate was raised (h2 > 0).

关键词： liquid metal cooling     heat sink     expanded microchannel     flow and thermal modeling    

HTML PDF 收藏

The development of ultralightweight expanded perlite-based thermal insulation panel using alkali activator

Damla Nur ÇELİK; Gökhan DURMUŞ

《结构与土木工程前沿（英文）》 2022年 第16卷 第11期   页码 1486-1499 doi: 10.1007/s11709-022-0881-6

摘要： The International Energy Agency (IEA) states that global energy consumption will increase by 53% by 2030. Turkey has 70% of the world’s perlite reserves, and in order to reduce energy consumption a thermal insulation panel was developed in Turkey using different particle sizes of expanded perlite (EP). In this study, 0–1.18 mm (powder) and 0–3 mm (granular) EP particle sizes were selected, since they have the lowest thermal conductivity coefficients among all the particle sizes. In addition, an alkali activator solution was used as a binder in the mixtures. The alkaline activator solution was obtained by mixing sodium hydroxide solution (6, 8, 10, and 12 mol·L−1) and sodium silicate (Module 3) at the different ratios of Na2SiO3 to NaOH of 1, 1.5, 2, and 2.5. This study aimed to experimentally determine the optimum binder and distribution ratio of EP, with the lowest coefficient of thermal conductivity and the lowest density. The lowest thermal conductivity and the lowest density were determined as 0.04919 W·m−1·K−1 and 133.267 kg/m3, respectively, in the sample prepared with 83.33% powder-size EP, 6 mol·L−1 sodium hydroxide solution, and ratio of Na2SiO3 to NaOH of 1.5. The density, thermal conductivity, and compressive strength of the sample showed the same trends of behavior when the Na2SiO3 to NaOH ratio was increased. In addition, the highest compressive strength was measured in 12 mol·L−1 NaOH concentration regardless of particle size. In conclusion, the study predicts that the EP-based thermal insulation panel can be used as an insulation material in the construction industry according to the TS825 Thermal Insulation Standard.

关键词： expanded perlite     alkali activator     thermal insulation panel     thermal conductivity    

HTML PDF 收藏

硝酸铵膨化技术及应用

吕春绪

《中国工程科学》 2000年 第2卷 第2期   页码 60-63

摘要：

硝酸铵膨化技术是一创新技术，创新设计的指导思想是硝酸铵自敏化，硝酸铵自敏化的提出是对国内外传统方法的突破。实施自敏化的技术途径是硝酸铵的膨化，其实质是表面活性技术在粉状炸药中的应用，是一个强制析晶的物理化学过程。文章重点讨论了硝酸铵膨化机理及膨化硝酸铵的技术特征，显示其独特的优点。硝酸铵膨化技术主要应用是岩石膨化硝铵炸药，给出了岩石膨化硝铵炸药的爆炸与物理特征数据，并与其它工业炸药做了比较。同时也推广应用在煤矿许用型炸药中。

关键词： 膨化硝酸铵     岩石     炸药     微结构     机理    

HTML PDF 收藏

Application of the expanded distinct element method for the study of crack growth in rock-like materials

Lei YANG, Yujing JIANG, Bo LI, Shucai LI, Yang GAO

《结构与土木工程前沿（英文）》 2012年 第6卷 第2期   页码 121-131 doi: 10.1007/s11709-012-0151-0

摘要： The expanded distinct element method (EDEM) was used to investigate the crack growth in rock-like materials under uniaxial compression. The tensile-shear failure criterion and the Griffith failure criterion were implanted into the EDEM to determine the initiation and propagation of pre-existing cracks, respectively. Uniaxial compression experiments were also performed with the artificial rock-like samples to verify the validity of the EDEM. Simulation results indicated that the EDEM model with the tensile-shear failure criterion has strong capabilities for modeling the growth of pre-existing cracks, and model results have strong agreement with the failure and mechanical properties of experimental samples. The EDEM model with the Griffith failure criterion can only simulate the splitting failure of samples due to tensile stresses and is incapable of providing a comprehensive interpretation for the overall failure of rock masses. Research results demonstrated that sample failure primarily resulted from the growth of single cracks (in the form of tensile wing cracks and shear secondary cracks) and the coalescence of two cracks due to the growth of wing cracks in the rock bridge zone. Additionally, the inclination angle of the pre-existing crack clearly influences the final failure pattern of the samples.

关键词： expanded distinct element method (EDEM)     crack growth     rock-like material     tensile-shear failure criterion     Griffith failure criterion     mechanical and failure behavior    

HTML PDF 收藏

膨化硝酸铵自敏化理论研究

吕春绪

《中国工程科学》 2000年 第2卷 第11期   页码 73-77

摘要：

膨化硝酸铵自敏化理论是膨化技术发明的核心，它是基于热点理论把微气泡植入硝酸铵炸药中。微气泡临界热点温度热力学计算为自敏化提供理论依据。与普通硝酸铵及珍珠岩相比较，微气泡在膨化硝酸铵内适当的分布为自敏化成功提供了有力的保证。

关键词： 膨化硝酸铵     自敏化     微气泡    

HTML PDF 收藏

Influence of influent on anaerobic ammonium oxidation in an Expanded Granular Sludge Bed-Biological Aerated

Daijun ZHANG, Cui BAI, Ting TANG, Qing YANG

《环境科学与工程前沿（英文）》 2011年 第5卷 第2期   页码 291-297 doi: 10.1007/s11783-010-0270-6

摘要： Shortcut nitrification-denitrification, anaerobic ammonium oxidation (ANAMMOX), and methanogenesis have been successfully coupled in an Expanded Granular Sludge Bed-Biological Aerated Filter (EGSB-BAF) integrated system. As fed different synthetic wastewater with chemical oxygen demand (COD) of 300–1200 mg·L and of 30–120 mg·L at the outer recycle ratio of 200%, the influence of influent on ANAMMOX in the integrated system was investigated in this paper. The experimental results showed that higher COD concentration caused an increase in denitrification and methanogenesis but a decrease in ANAMMOX; however, when an influent with the low concentration of COD was used, the opposite changes could be observed. Higher influent concentration favored ANAMMOX when the COD concentration of influent was fixed. Therefore, low ratio would decrease competition for nitrite between ANAMMOX and denitrification, which was favorable for reducing the negative effect of organic COD on ANAMMOX. The good performance of the integrated system indicated that the bacterial community of denitrification, ANAMMOX, and methanogenesis could be dynamically maintained in the sludge of EGSB reactor for a certain range of influent.

关键词： Expanded Granular Sludge Bed-Biological Aerated Filter (EGSB-BAF) integrated system     the influence of influent     anaerobic ammonium oxidation (ANAMMOX)     shortcut nitrification-denitrification     methano-genesis    

HTML PDF 收藏

扩大乙烯装置原料来源的思考与实践

曹湘洪

《中国工程科学》 2001年 第3卷 第5期   页码 35-43

摘要：

从烃类原料裂解制乙烯的裂解性能和烃类馏份馏程及组成相关研究结果出发，提出了与世界乙烯原料轻质化的大趋势不同的扩大乙烯原料来源的思路：大庆原油的重馏份油即常三、减一线油和减二、减三线油酮苯脱蜡副产的蜡下油可以作乙烯原料。总结了该原料性能测试、模拟裂解炉评价及工业装置上应用的结果，证明该原料裂解时有较高的乙烯收率，也能保证裂解炉较长的运行周期，有明显的经济效益。

关键词： 乙烯     原料     来源    

HTML PDF 收藏

Effect of nitrobenzene on the performance and bacterial community in an expanded granular sludge bed

Jun Li, Wentao Li, Gan Luo, Yan Li, Aimin Li

《环境科学与工程前沿（英文）》 2019年 第13卷 第1期 doi: 10.1007/s11783-019-1090-y

摘要：

Less than 50 mg/L nitrobenzene brought little effect on anaerobic sulfate reduction.

Kinetics of sulfate reduction under different nitrobenzene contents was studied.

Increased nitrobenzene contents greatly changed the bacterial community structure.

Genus Desulfovibrio played the key role in anaerobic sulfate reduction process.

关键词： Nitrobenzene (NB)     Sulfate-reducing bacteria (SRB)     Bacterial community     Sulfate reduction     High-throughput sequencing    

HTML PDF 收藏

内循环式封闭空间膨胀珍珠岩除湿试验研究

陈小兰,赵映,朱和霖,孙敢,王洪亮,张瑞宏

《中国工程科学》 2011年 第13卷 第9期   页码 101-104

摘要：

设计了一种封闭空间膨胀珍珠岩除湿的吸附系统，进行了湿空气流速、吸附剂层数和吸附剂铺放密度的单因素试验和三因素三水平正交试验，分析了各因素对除湿系统除湿性能的影响关系。试验结果表明，随着气流速度的增加，除湿速度随之增大，单位能耗也相应地减少，在一定范围内可采用相对较高湿空气流速，提高除湿效率；随着吸附剂层数的增多，除湿能力提高；随着吸附剂铺放密度的增加，湿空气与吸附剂颗粒之间的传热传质能力得到提高，除湿速率增大，单位能耗相对减少。

关键词： 内循环式     封闭空间     膨胀珍珠岩     除湿     温室    

HTML PDF 收藏

Instantaneous deflection of light-weight concrete slabs

Behnam VAKHSHOURI, Shami NEJADI

《结构与土木工程前沿（英文）》 2017年 第11卷 第4期   页码 412-423 doi: 10.1007/s11709-017-0416-8

摘要： Construction loading before the age of 28 d can have the most significant effects on the slabs, especially for multi-story structures. The changing properties of the young concrete complicate the prediction of serviceability design requirements also. An experimental investigation is performed on four simply supported Light-Weight Concrete (LWC) one-way slabs subjected to immediate loading at 14 d. Effects of aggregate type, loading levels and cracking moment together with the influences of ultimate moment capacity and service moment on the instantaneous deflection of slabs are studied. Comparison of the obtained results with predictions of existing models in the literature shows considerable differences between the recorded and estimated instantaneous deflection of LWC slabs. Based on sensitivity analysis of the effective parameters, a new equation is proposed and verified to predict the instantaneous deflection of LWC slabs subjected to loading at the age of 14 d.

关键词： instantaneous deflection     light-weight concrete     expanded polystyrene     effective moment of inertia     cracking moment     moment capacity     service moment    

HTML PDF 收藏

Digital representation of meso-geomaterial spatial distribution and associated numerical analysis of geomechanics: methods, applications and developments

YUE Zhongqi

《结构与土木工程前沿（英文）》 2007年 第1卷 第1期   页码 80-93 doi: 10.1007/s11709-007-0008-0

摘要： This paper presents the author's efforts in the past decade for the establishment of a practical approach of digital representation of the geomaterial distribution of different minerals, particulars, and components in the meso-scale range (0.1 to 500 mm). The primary goal of the approach is to provide a possible solution to solve the two intrinsic problems associated with the current main-stream methods for geomechanics. The problems are (1) the constitutive models and parameters of soils and rocks cannot be given accurately in geomechanical prediction; and (2) there are numerous constitutive models of soils and rocks in the literature. The problems are possibly caused by the homogenization or averaging method in analyzing laboratory test results for establishing the constitutive models and parameters. The averaging method employs an assumption that the test samples can be represented by a homogeneous medium. Such averaging method ignores the fact that the geomaterial samples are also consisted of a number of materials and components whose properties may have significant differences. In the proposed approach, digital image processing methods are used as measurement tools to construct a digital representation for the actual spatial distribution of the different materials and components in geomaterial samples. The digital data are further processed to automatically generate meshes or grids for numerical analysis. These meshes or grids can be easily incorporated into existing numerical software packages for further mechanical analysis and failure prediction of the geomaterials under external loading. The paper presents case studies to illustrate the proposed approach. Further discussions are also made on how to use the proposed approach to develop the geomechanics by taking into account the geomaterial behavior at micro-scale, meso-scale and macro-scale levels. A literature review of the related developments is given by examining the SCI papers in the database of Science Citation Index Expanded. The results of this review have shown that the proposed approach is one of the latest research and developments in geomechanics where actual spatial distribution and properties of materials and components at the meso-level are taken into account.

关键词： homogeneous     numerical analysis     Expanded     homogenization     meso-level    

HTML PDF 收藏

硝酸铵膨化理论研究

吕春绪

《中国工程科学》 2001年 第3卷 第9期   页码 58-63

摘要：

描述了硝酸铵膨化过程，计算与测定了其物理化学参数，研究了膨化过程的影响因素，并给出了膨化过程可能的机理。

关键词： 膨化硝酸铵     膨化理论     物理化学参数     影响因素    

HTML PDF 收藏

On corrosion to stainless steel by calcium chloride with different extender

Lv XU, Yuanyang HU, Liwei WANG, Ruzhu WANG,

《能源前沿（英文）》 2010年 第4卷 第2期   页码 181-184 doi: 10.1007/s11708-009-0065-2

摘要： A calcium chloride solution with a different extender, which is made up of either pure calcium chloride, calcium chloride with expanded graphite, or calcium chloride with activated carbon, acts differently on stainless steel. The mass ratio between calcium chloride with expanded graphite or activated carbon is almost 4∶1, which is demonstrated to be the optimum ratio. The experimental research in this paper reveals that, of the three solutions, which are pure calcium chloride, calcium chloride with expanded graphite, and calcium chloride with activated carbon, the strongest oxidation creation and pitting corrosion happened in the solution of calcium chloride with expanded graphite, the weakest oxidation creation happened in the solution of calcium chloride with activated carbon, and pitting corrosion was stronger than oxidation creation in the solution of pure calcium chloride. This paper gives the reasons for these phenomena. Furthermore, based on theory analysis, multiple means and approaches are provided to prevent stainless steel from further corroding.

关键词： stainless steel     corrosion     calcium chloride     expanded graphite     activated carbon     oxidation creation     pitting corrosion    

HTML PDF 收藏

Permeability and thermal conductivity of host compressed natural graphite for consolidated activated carbon adsorbent

Bo TIAN, Liwei WANG, Zhequan JIN, Ruzhu WANG

《能源前沿（英文）》 2011年 第5卷 第2期   页码 159-165 doi: 10.1007/s11708-011-0145-y

摘要： Permeability and thermal conductivity test units were set up to study the heat and mass transfer performance of the host material, i.e. expanded natural graphite (ENG), for consolidated activated carbon (AC) adsorbent. The permeability was tested with nitrogen as the gas source, and the thermal conductivity was studied using steady-state heat source method. The results showed that the values of permeability and thermal conductivity were 10 to 10 m and 1.7 to 3.2 W/(m·K), respectively, while the density compressed expanded natural graphite (CENG) varied from 100 to 500 kg/m . The permeability decreased with the increasing density of CENG, whereas the thermal conductivity increased with the increasing density of CENG. Then the thermal conductivity and permeability of granular AC were researched. It was discovered that the thermal conductivity of samples with different grain size almost kept constant at 0.36 W/(m·K) while the density was approximately 600 kg/m . This means that the thermal conductivity was not related to the grain size of AC. The thermal conductivity of CENG was improved by 5 to 10 times compared with that of granular AC. Such a result showed that CENG was a promising host material for AC to improve the heat transfer performance, while the mass transfer performance should be considered in different conditions for utilization of adsorbent.

关键词： permeability     thermal conductivity     expanded nature graphite     activated carbon    

HTML PDF 收藏

标题 作者 时间 类型 操作

Reliability mesh convergence analysis by introducing expanded control variates

Alireza GHAVIDEL, Mohsen RASHKI, Hamed GHOHANI ARAB, Mehdi AZHDARY MOGHADDAM

期刊论文

Flow and thermal modeling of liquid metal in expanded microchannel heat sink

期刊论文

The development of ultralightweight expanded perlite-based thermal insulation panel using alkali activator

Damla Nur ÇELİK; Gökhan DURMUŞ

期刊论文

硝酸铵膨化技术及应用

吕春绪

期刊论文

Application of the expanded distinct element method for the study of crack growth in rock-like materials

Lei YANG, Yujing JIANG, Bo LI, Shucai LI, Yang GAO

期刊论文

膨化硝酸铵自敏化理论研究

吕春绪

期刊论文

Influence of influent on anaerobic ammonium oxidation in an Expanded Granular Sludge Bed-Biological Aerated

Daijun ZHANG, Cui BAI, Ting TANG, Qing YANG

期刊论文

扩大乙烯装置原料来源的思考与实践

曹湘洪

期刊论文

Effect of nitrobenzene on the performance and bacterial community in an expanded granular sludge bed

Jun Li, Wentao Li, Gan Luo, Yan Li, Aimin Li

期刊论文

内循环式封闭空间膨胀珍珠岩除湿试验研究

陈小兰,赵映,朱和霖,孙敢,王洪亮,张瑞宏

期刊论文

Instantaneous deflection of light-weight concrete slabs

Behnam VAKHSHOURI, Shami NEJADI

期刊论文

Digital representation of meso-geomaterial spatial distribution and associated numerical analysis of geomechanics: methods, applications and developments

YUE Zhongqi

期刊论文

硝酸铵膨化理论研究

吕春绪

期刊论文

On corrosion to stainless steel by calcium chloride with different extender

Lv XU, Yuanyang HU, Liwei WANG, Ruzhu WANG,

期刊论文

Permeability and thermal conductivity of host compressed natural graphite for consolidated activated carbon adsorbent

Bo TIAN, Liwei WANG, Zhequan JIN, Ruzhu WANG

期刊论文