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Weak Expansive Soil Physical Properties Modification by Means of a Cement-Jute Fiber

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Fluid Dynamics & Materials Processing 2023年第8期19卷 2119-2130页

作者： Zisheng Yang Wendong Li Xuelei Cheng ran hai Shunqun Li School of Architectural and Civil Engineering Zhongyuan University of TechnologyZhengzhou450007China Yellow River Institute of Hydraulic Research Zhengzhou450003China School of Civil Engineering Tianjin Chengjian UniversityTianjin300384China

Sixteen groups of comprehensive tests have been conducted to investigate the modifications in the physical properties of a weak expansive soil due to the addition of a cement jute fiber.The tests have been conducted to analyze the liquid plastic limit,the particle distribution and the free expansion rate.The results show that:(1)With an increase in the cement-jute fiber content,the free expansion rate of the modified expansive soil gradually decreases,however,such a rate rebounds when the fiber content exceeds 0.5%and the cement content exceeds 6%.(2)With an increase in the cement percentage,the particle unevenness coefficient(Cu)and curvature coefficient(Cc)of the modified expansive soil tend to grow gradually.The Cc coefficient reaches 1.0 when the cement content is 6%.The unevenness coefficient of 16 soil samples is greater than 5.0,however,the Cu coefficient decreases when the cement content reaches 6%.(3)The plastic limit of soil increases as the cement content is made higher,while the liquid limit and plastic index decrease gradually.When the content of the modified material is 2%+0.1%~2%+0.7%(Cement content+jute fiber content),the change of particle size distribution is most obvious.(4)When the contents of cement and jute fiber are is 6%and 0.5%,respectively,the modification induced in the physical properties of soil samples corresponds to the best case.

关键词： Cement jute fiber expansive soil expansion optimal dosage

不同粉煤灰掺量下SCC单轴压缩试验离散元数值分析

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人民黄河 2024年第7期46卷 143-147页

作者：程学磊王亚佐刘俊霞郑锦辉海然何鲜峰中原工学院建筑工程学院河南郑州450007 黄河水利委员会黄河水利科学研究院河南郑州450003

为了研究不同粉煤灰掺量自密实混凝土的力学性能变化及破坏性状,利用PFC2D中的FISH语言及该程序自带的线性黏结模型,建立不同粉煤灰掺量自密实混凝土单轴压缩试验离散元模型,并与实际试验结果进行对比,分析其内部破坏形态与力链变化。... 详细信息

为了研究不同粉煤灰掺量自密实混凝土的力学性能变化及破坏性状,利用PFC2D中的FISH语言及该程序自带的线性黏结模型,建立不同粉煤灰掺量自密实混凝土单轴压缩试验离散元模型,并与实际试验结果进行对比,分析其内部破坏形态与力链变化。研究表明:不同粉煤灰掺量FA-SCC的极限强度呈先增后减的趋势,破坏裂缝均为对角裂缝,区别在于中部竖向裂纹数量不同,建立的二维离散元数值模型可以很好地模拟粉煤灰自密实混凝土结构轴压破坏时材料内部微裂纹产生、裂缝扩展及对角贯通裂缝形成的过程,弥补了室内试验仅仅依靠肉眼观测的不足,同时模型输出的不同粉煤灰掺量自密实混凝土的轴压强度及应力应变曲线与实验室试验结果高度贴合,最大抗压强度误差不超过7.1%。

关键词：自密实混凝土粉煤灰单轴压缩离散元分析

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不同米勒循环方案汽油机性能仿真与试验研究

内燃机与配件 2024年第4期 10-13页

作者：鞠金宝杨帅刘海然刘海峰吴名芝同济大学汽车学院上海201804 上海电子信息职业技术学院上海201424 南昌智能新能源汽车研究院江西南昌330044

本课题借助某1.5L自然吸气汽油机进行配气机构改型以实现米勒循环,基于一维软件计算选取不同凸轮型线,研究不同方案实现新机油耗及额定扭矩性能目标的差异。借助三维CFD软件,对选取配气组合方案建立缸内流动模型,计算流场分布,对火花塞... 详细信息

本课题借助某1.5L自然吸气汽油机进行配气机构改型以实现米勒循环,基于一维软件计算选取不同凸轮型线,研究不同方案实现新机油耗及额定扭矩性能目标的差异。借助三维CFD软件,对选取配气组合方案建立缸内流动模型,计算流场分布,对火花塞附近流场、湍动能进行计算;计算出缸内压力和温度场分布,为开发试验提供必要的计算流体力学输入。另外,借助性能试验台,对改型后的样机开展了性能开发试验,验证了实际收益,最终实现了满足设计目标的方案选型。

关键词：汽油机米勒循环比油耗 CFD计算

Temperature and Pressure Effects on Terahertz Time-Domain Spectroscopy of Crystalline Methedrine by Molecular Dynamics Simulation

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Advances in Molecular Imaging 2014年第4期4卷 58-69页

作者： Yu Xin Hassan Yousefi Oderji ran hai Cailong Fu Raja Aljarmouzi Hongbin Ding School of Physics and Optical Engineering Key Laboratory of Materials Modification by Laser Ion and Electron Beams Chinese Ministry of Education Dalian University of Technology Dalian China

In this study, the terahertz time-domain spectroscopy (THz-TDS) of crystalline methedrine, which is one of the illegal drugs, is performed using molecular dynamics simulation by the Fourier transform of time derivative auto-correlation functions of the dipole moment. In order to accurately detect the drugs from samples, it is necessary to build a complete database for terahertz spectra under different external conditions from theoretical calculation, which are hardly obtained from the experiments directly. Our results show remarkable consistency with the available experimental data in the frequency range of 10 - 100 cm-1 indicating that the presented method has significant capability to simulate terahertz spectra at various conditions. We investigated the effects of temperature and pressure on THz-TDS by simulating the system at temperature range between 78.4 K and 400 K at pressures up to 100 atm. Results show the spectral features of THz-TDS both in intensity and profile are highly sensitive to the variation of temperature and with a lower magnitude to the variation of pressure. The vanishing, rebuilding and shifting of spectral peaks are due to the complex mechanisms such as the anharmonicity, shifting in the vibration energy levels, formation and destruction of hydrogen-binding and the deformation of the potential energy surface during the environment changing. This improved our understanding for complicated THz-TDS of crystalline methedrine and would be useful for assignment of the practical measurements.

关键词： Methedrine Molecular Dynamics Simulation Terahertz Time-Domain Spectroscopy

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建筑用膨胀珍珠岩的资源特性及研究现状分析

节能 2024年第3期43卷 115-117页

作者：李建伟马炎张璐刘俊霞张茂亮海然河南建筑材料研究设计院有限责任公司河南郑州450052 中原工学院河南郑州450000

对国内外建筑用膨胀珍珠岩的相关产品标准进行梳理,对膨胀珍珠岩的化学成分、微观结构及亲水机理进行分析,指出保持膨胀珍珠岩优异绝热性能的关键是改变其表层的亲水官能团及微孔结构,总结有机硅憎水剂喷涂、聚合物包覆、SiO2气凝胶填... 详细信息

对国内外建筑用膨胀珍珠岩的相关产品标准进行梳理,对膨胀珍珠岩的化学成分、微观结构及亲水机理进行分析,指出保持膨胀珍珠岩优异绝热性能的关键是改变其表层的亲水官能团及微孔结构,总结有机硅憎水剂喷涂、聚合物包覆、SiO2气凝胶填充等膨胀珍珠岩改性方法的机理及研究现状,为相关技术人员生产或使用膨胀珍珠岩提供参考。

关键词：膨胀珍珠岩绝热性能改性方法

One-step conversion of methane and formaldehyde to ethanol over SA-FLP dual-active-site catalysts: A DFT study

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Chinese Chemical Letters 2024年第4期35卷 544-548页

作者： Tao Ban Xi-Yang Yu hai-Kuo Tian Zheng-Qing Huang Chun-ran Chang Shaanxi Key Laboratory of Energy Chemical Process Intensification School of Chemical Engineering and TechnologyXi'an Jiaotong UniversityXi'an 710049China Shaanxi Key Laboratory of Low Metamorphic Coal Clean Utilization School of Chemistry and Chemical EngineeringYulin UniversityYulin 719000China

One-step conversion of methane and formaldehyde into ethanol is a 100% atom-efficient process for carbon resources utilization and environment protection but still faces eminent challenges due to the lacking of efficient catalysts. Therefore, developing active and stable catalysts is crucial for the co-conversion of methane and formaldehyde. Herein, twelve kinds of “Single-Atom”-“Frustrated Lewis Pair”(SA-FLP)dual-active-site catalysts are designed for the direct conversion of methane and formaldehyde to ethanol based on density functional theory(DFT) calculations and microkinetic simulations. The results show that the SA-FLP dual active sites can simultaneously activate methane at the SA site and activate formaldehyde at the FLP site. Among the twelve designed SA-FLP catalysts, Fe1-FLP shows the best performance in the co-conversion of methane and formaldehyde to ethanol with the rate-determining barrier of 1.15 e V.Ethanol is proved as the main product with the turnover frequency of 1.32 × 10^(-4)s^(-1)at 573 K and 3 bar.This work provides a universal strategy to design dual active sites on metal oxide materials and offers new insights into the effective conversion of methane and formaldehyde to desired C_(2) chemicals.

关键词： Single-atom Frustrated Lewis pairs Methane conversion Dual active sites Ethanol synthesis

NADPH Oxidase Accounts for Changes in Cerebrovascular Redox Status in Hindlimb Unweighting Rats

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Biomedical and Environmental Sciences 2015年第11期28卷 799-807页

作者： PENG Liang ran hai Hong ZHANG Ying ZHAO Yu FAN Yong Yan PENG Li ZHANG ran CAO Feng Department of Cardiology Chinese People's Liberation Army General Hospital Department of Geriatric Hematology Chinese People's Liberation Army General Hospital

Objective The roles of cerebrovascular oxidative stress in vascular functional remodeling have been described in hindlimb-unweighting （HU） rats. However, the underlying mechanism remains to be established. Methods We investigated the generation of vascular reactive oxygen species （ROS）, Nox2/Nox4 protein and mRNA levels, NADPH oxidase activity, and manganese superoxide dismutase （MnSOD） and glutathione peroxidase-1 （GPx-1） mRNA levels in cerebral and mesenteric smooth muscle cells （VSMCs） of HU rats. Results ROS production increased in cerebral but not in mesenteric VSMCs of HU rats compared with those in control rats. Nox2 and Nox4 protein and mRNA levels were increased significantly but MnSOD/GPx-1 mRNA levels decreased in HU rat cerebral arteries but not in mesenteric arteries. NADPH oxidases were activated significantly more in cerebral but not in mesenteric arteries of HU rats. NADPH oxidase inhibition with apocynin attenuated cerebrovascular ROS production and partially restored Nox2/Nox4 protein and mRNA levels, NADPH oxidase activity, and MnSOD/GPx-1 mRNA levels in cerebral VSMCs of HU rats. Conclusion These results suggest that vascular NADPH oxidases regulate cerebrovascular redox status and participate in vascular oxidative stress injury during simulated microgravity.

关键词： Microgravity Oxidative stress NADPH oxidase Manganese superoxide dismutase Glutathione peroxidase-1

Transparent micropatterned conductive films based on highlyordered nanowire network

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Nano Research 2024年第5期17卷 4288-4297页

作者： Xin-ran Zhang hai-Tao Deng Xu Zeng Yi-Lin Wang Peng Huang Xiao-Sheng Zhang School of Integrated Circuit Science and Engineering University of Electronic Science and Technology of ChinaChengdu 611731China

Transparent conductive films that are based on nanowire networks are essential to construct flexible,wearable,and even stretchable electronics.However,large-scale precise micropatterning,especially with regard to the controllability of the organizing orientation of nanowires,is a critical challenge.Herein,we proposed a liquid film rupture self-assembly approach for manufacturing transparent conductive films with microstructure arrays based on a highly ordered nanowire network.The large-scale microstructure conductive films were fabricated through air-liquid interface self-assembly and liquid film rupture self-assembly.Six typical micropattern morphologies,including square,hexagon,circle,serpentine,etc.,were prepared to reveal the universal applicability of the proposed approach.The homogeneity and controllability of this approach were verified for multiple assemblies.With the assembly cycles increasing,the optical transmittance decreases slightly.In addition,theoretical model analysis is carried out,and the analytical formula of the speed of the film moving with the surface tension and the density of the liquid film is presented.Finally,the feasibility of this approach for piezoresistive strain sensors is verified.This fabrication approach demonstrated a cost-effective and efficient method for precisely arranging nanowires,which is useful in transparent and wearable applications.

关键词： flexible electronics transparent conductive network micropatterning nanowires micro electromechanical systems(MEMS)

Triangular Halogen Bond and Hydrogen Bond Supramolecular Complex Consisting of Carbon Tetrabromide, Halide, and Solvent Molecule： A Theoretical and Spectroscopic Study

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Chinese Journal of Chemical Physics 2014年第3期27卷 265-273页

作者： Yu-jie Wu Xiao-ran Zhao hai-yue Gao Wei-jun Jin College of Chemistry Beijing Normal University Beijing 100875 China

理论计算和分光镜的实验显示一种三角形三结合的超分子的建筑群 CBr4XH-C，它由碳 tetrabromide，卤化物，和 protic 溶剂组成分子(指 dichloromethane，氯仿和 acetonitrile ) ，能在答案被形成。在把卤化物用作普通领受人的三角形的... 详细信息

理论计算和分光镜的实验显示一种三角形三结合的超分子的建筑群 CBr4XH-C，它由碳 tetrabromide，卤化物，和 protic 溶剂组成分子(指 dichloromethane，氯仿和 acetonitrile ) ，能在答案被形成。在把卤化物用作普通领受人的三角形的建筑群的卤素和氢契约的力量服从碘化物的命令 > 溴化物 > 氯化物。卤素和氢契约 weak-cooperatively 工作。在 CBr4 和卤化物之间的卤素结合建筑群的费用转移乐队在 1:1，形成常数 K 和结合的卤素的臼齿的扑灭系数的三溶剂，然后 stoichiometry 在紫外力的吸收光谱学被观察建筑群被 Benesi-Hildebrand 获得方法。K 和表演溶剂电介质常数上的依赖并且总体上，服从碘化物的一个命令 > 溴化物 > 在一样的溶剂的氯化物。而且，溶剂分子的 C-H 震动的频率与卤化物的增加显然变化，它显示 C-HX 相互作用。试验性的数据显示卤素契约和氢契约由分享由计算预言了的一个普通卤化物领受人共存。

关键词：超分子复合物溶剂分子配合物组成光谱实验三角形溴化氢键卤素