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Three-dimensional finite difference analysis of shallow sprayed concrete tunnels crossing a reverse fault

Masoud RANJBARNIA, Milad ZAHERI, Daniel DIAS

《结构与土木工程前沿（英文）》 2020年 第14卷 第4期   页码 998-1011 doi: 10.1007/s11709-020-0621-8

摘要： Urban tunnels crossing faults are always at the risk of severe damages. In this paper, the effects of a reverse and a normal fault movement on a transversely crossing shallow shotcreted tunnel are investigated by 3D finite difference analysis. After verifying the accuracy of the numerical simulation predictions with the centrifuge physical model results, a parametric study is then conducted. That is, the effects of various parameters such as the sprayed concrete thickness, the geo-mechanical properties of soil, the tunnel depth, and the fault plane dip angle are studied on the displacements of the ground surface and the tunnel structure, and on the plastic strains of the soil mass around tunnel. The results of each case of reverse and normal faulting are independently discussed and then compared with each other. It is obtained that deeper tunnels show greater displacements for both types of faulting.

关键词： urban tunnel     sprayed concrete     reverse fault     normal fault     finite difference analysis    

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Temperature difference-powered carbon nanotube bearings

Quanwen HOU, Bingyang CAO, Zengyuan GUO

《能源前沿（英文）》 2011年 第5卷 第1期   页码 49-52 doi: 10.1007/s11708-010-0111-0

摘要： Molecular dynamics simulations are conducted to study the motion of carbon nanotube-based nanobearings powered by temperature difference. When a temperature difference exists between stator nanotubes, the rotor nanotubes acquire a higher temperature, which arises from the interaction between phonon currents and nanotubes. The thermal driving force increases with the increase in temperature difference between the stators, an increase that is nearly proportional to the temperature difference. Confined by the minimum energy track, the (5, 5)@(10, 10) nanotube bearings only translate along the axis direction but without successive rotation.

关键词： temperature difference-induced motion     carbon nanotubes     nanobearing     molecular dynamics simulation    

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类差分平衡函数的性质及其应用

张文英,李世取

《中国工程科学》 2004年 第6卷 第3期   页码 45-52

摘要：

定义了布尔函数的类差分和类差分平衡函数，研究了类差分平衡函数的密码学性质以及构造方法。作为类差分平衡函数的应用，给出了〓上逻辑函数是完全非线性函数的充要条件，并在首先分析得到所有四元类差分平衡函数的基础上，编程搜索出〓上所有的完全非线性函数。

关键词： Bent函数     完全非线性函数     2-基展开     类差分     类自相关函数     类差分平衡函数    

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Analysis of the treatment outcomes of esophageal variceal bleeding patients from multiple centers in

WANG Zhiqiang

《医学前沿（英文）》 2008年 第2卷 第2期   页码 171-173 doi: 10.1007/s11684-008-0031-0

摘要： This study aimed to investigate the treatment outcomes of esophageal variceal bleeding (EVB) in China. A total of 1087 cases were collected from 19 hospitals in 16 large and medium sized cities across China between January 1st, 2005 and January 1st, 2006. There were 313 cases (29.0%) of mild (<400 mL), 494 cases (45.8%) of moderate (400–1500 mL) and 272 cases (25.2%) of severe (>1500 mL) bleeding. Successful hemostasis was achieved in 89.8% of cases. Seven hundred and eighty-five cases were treated by medication with a hemostasis rate of 91.8%. Seventy-one cases were treated using a Sengstaken-Blakemore tube with a hemostasis rate of 54.9%. Thirty-seven cases were treated with emergency endoscopic variceal ligation with a hemostasis rate of 83.8%. Seventy-seven cases were treated with endoscopic sclerotherapy with a hemostasis rate of 94.8%. Forty-three cases were treated with emergency surgical operation with a hemostasis rate of 95.3%. Sixty-six cases were treated with combined therapy with a hemostasis rate of 97.0%. There was a significant difference ( < 0.01) in the successful hemostasis rate between different treatments. The overall mortality was 10.1%, among which 6.6% was directly caused by bleeding. The multivariate logistic regression analysis shows that the severity of bleeding, treatment methods, liver dysfunction and activation of hepatitis were predictive factors for successful hemostasis. Most cases of EVB were mild and moderate in severity. The first-line treatment for EVB is medication. Emergency endoscopic intervention has not been widely available yet. The overall management outcome of EVB has been improved.

关键词： significant difference     predictive     medication     first-line treatment     bleeding    

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Synthesis of Intermittent-Motion Linkages with Slight Difference in Length Between Links

CHEN Xin-bo, YU Zhen

《机械工程前沿（英文）》 2006年 第1卷 第1期   页码 76-79 doi: 10.1007/s11465-005-0007-6

摘要：

The design of intermittent-motion linkages using traditional methods is usually complicated. In this paper, (1) a new method for realizing intermittent motion, using linkages with a slight difference in length between links, is studied; (2) some new types of intermittent-motion linkages and their software for visual analysis and design are developed; and (3) influences of some design parameters on intermittent-motion characteristics are clarified. Results confirmed that the theory and the software are useful, making the synthesis of intermittent-motion linkages clear and easy.

关键词： synthesis     useful     intermittent     intermittent-motion     traditional    

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温差能与低温海水资源综合利用研究

付强,王国荣,周守为,钟林,张理,余兴勇,杨浦

《中国工程科学》 2021年 第23卷 第6期   页码 52-60 doi: 10.15302/J-SSCAE-2021.06.007

摘要：

我国海洋温差能资源量巨大，主要分布在广东省和南海海域，是区域能源结构优化以实现碳达峰、碳中和的有效支撑，也是未来我国南海、 21 世纪海上丝绸之路沿线诸多岛屿能源补给保障的重要途径；目前海洋温差能发电（ OTEC）技术和装备尚处于实验阶段，兆瓦级试验电站建设成本巨大，整体技术成熟度不及商业级利用规模，亟待发展突破。本文总结了国内外 OTEC 及综合利用的发展模式、技术装备所面临的挑战，针对南海温差能资源开发困境、广东省液化天然气（ LNG）冷能资源浪费等情况，提出了以 LNG 气化的低温海水替代深层海水进行温差能发电的新途径。建议以珠海 LNG 气化站为例，探索 LNG 冷能回收 – 温差能发电、低温冷海水综合利用示范基地的发展模式；通过初步概算示范基地的投资与收益，完成了相应模式的经济与技术可行性论证。相关发展模式建议、应用案例论证过程，可为我国温差能与低温海水资源综合利用提供技术借鉴和应用参考。

关键词： 海洋温差能     低温海水资源     LNG冷能     综合利用     温差能发电    

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Spent rechargeable lithium batteries in e-waste: composition and its implications

Xianlai ZENG,Jinhui LI

《环境科学与工程前沿（英文）》 2014年 第8卷 第5期   页码 792-796 doi: 10.1007/s11783-014-0705-6

摘要： The amount of spent rechargeable lithium batteries (RLBs) is growing rapidly owing to wide application of these batteries in portable electronic devices and electric vehicles, which obliges that spent RLBs should be handled properly. Identification of spent RLBs can supply fundamental information for spent RLBs recycling. This study aimed to determine the differences of physical components and chemical compositions among various spent RLBs. All the samplings of RLBs were rigorously dismantled and measured by an inductive coupled plasma atomic emission spectrometer. The results indicate that the average of total weight of the separator, the anode and the cathode accounted for over 60% of all the RLBs. The weight ratio of valuable metals ranged from 26% to 76%, and approximately 20% of total weight was Cu and Al. Moreover, no significant differences were found among different manufacturers, applications, and electrolyte types. And regarding portable electronic devices, there is also no significant difference in the Co-Li concentration ratios in the leaching liquid of RLBs.

关键词： rechargeable lithium batteries     e-waste     physical components     difference analysis     recycling    

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多星联合定位理论性能分析 Article

Ding WANG,Shuai WEI,Ying WU

《信息与电子工程前沿（英文）》 2016年 第17卷 第12期   页码 1360-1387 doi: 10.1631/FITEE.1500285

摘要： 为利用卫星束确定地球表面目标的位置信息具有很多重要应用，例如导航，监控，遥感等。然而，在实际条件下，会有很多因素影响卫星定位系统的精度，比如说信号参数的测量误差，卫星位置误差以及校正源的位置误差。本文基于时差观测量系统分析了多星联合定位的理论性能。首先在基于目标高程约束和高斯误差的假设下，推导四种定位场景下目标位置估计方差的克拉美罗界。第一种场景仅考虑时差观测量误差，并且假设卫星位置精确已知；第二种场景同时考虑时差观测量误差和卫星位置误差；第三种场景假设存在若干位置信息精确已知的校正源，其用于消除卫星位置的影响；第四种场景则假设校正源位置也存在测量误差。此外，文中基于一阶扰动分析和拉格朗日方法推导了两种情形下的定位均方根误差的表达式。第一种情形是假设卫星位置精确已知但实际上却含有误差；第二种情形则是假设校正源位置精确已知但实际上却含有误差。仿真结果验证了文中理论分析的有效性。

关键词： 卫星定位；时差；克拉美罗界；校正源；性能分析    

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The Difference Effect of Environmental Regulation on Two Stages of Technology Innovation in China’s Manufacturing

Bao-long Yuan,Sheng-gang Ren,Xing Hu,Xuan-yu Yang

《工程管理前沿（英文）》 2016年 第3卷 第1期   页码 24-29 doi: 10.15302/J-FEM-2016007

摘要： This paper divides technological innovation into two stages: technology development and technology transfer. Then the authors use the panel data of 28 manufacturing industries during 2003–2012 to test the econometric regression model for the industry of the sub stages, which is a regulation on technological innovation in the environment. The results show that: (1) environmental regulation has a significant role in promoting China’s manufacturing technology research patent achievements, and technology into new products, and this indicated that “Porter hypothesis” in the manufacturing sector has been verified; (2) R&D and transfer expenditure have a positive impact on technological innovation. Finally, the authors put forward the corresponding policy recommendations for industry of the environmental regulation on the impact of technological innovation in phases.

关键词： environmental regulation     technology innovation     stage difference     manufacturing    

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Application of random set method in a deep excavation: based on a case study in Tehran cemented alluvium

Arash SEKHAVATIAN, Asskar Janalizadeh CHOOBBASTI

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 66-80 doi: 10.1007/s11709-018-0461-y

摘要： The design of high-rise buildings often necessitates ground excavation, where buildings are in close proximity to the construction, thus there is a potential for damage to these structures. This paper studies an efficient user-friendly framework for dealing with uncertainties in a deep excavation in layers of cemented coarse grained soil located in Tehran, Iran by non-deterministic Random Set (RS) method. In order to enhance the acceptability of the method among engineers, a pertinent code was written in FISH language of FLAC2D software which enables the designers to run all simulations simultaneously, without cumbersome procedure of changing input variables in every individual analysis. This could drastically decrease the computational effort and cost imposed to the project, which is of great importance especially to the owners. The results are presented in terms of probability of occurrence and most likely values of the horizontal displacement at top of the wall at every stage of construction. Moreover, a methodology for assessing the credibility of the uncertainty model is presented using a quality indicator. It was concluded that performing RS analysis before the beginning of every stage could cause great economical savings, while improving the safety of the project.

关键词： uncertainty     reliability analysis     deep excavations     random set method     finite difference method    

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Molecular dynamics study of water diffusion in an amphiphilic block copolymer with large difference in

Yang Zhou, Phillip Choi

《化学科学与工程前沿（英文）》 2017年 第11卷 第3期   页码 440-447 doi: 10.1007/s11705-017-1626-2

摘要： Isothermal-isobaric molecular dynamics simulation was used to study the diffusion mechanism of water in polyurethane- -poly( -isopropyl acrylamide) (PU- -PNIPAm) with a hydrophobic PU/hydrophilic PNIPAm mass ratio of 1.4 to 1 at 298 K and 450 K. Here, the experimental glass transition temperature ( ) of PU is 243 K while that of PNIPAm is 383 K. Different amounts of water up to 15 wt-% were added to PU- -PNIPAm. We were able to reproduce the specific volumes and glass transition temperatures (250 K and 390 K) of PU- -PNIPAm. The computed self-diffusion coefficient of water increased exponentially with increasing water concentration at both temperatures (i.e., following the free volume model of Fujita). It suggested that water diffusion in PU- -PNIPAm depends only on its fractional free volume despite the free volume inhomogeneity. It is noted that at 298 K, PU is rubbery while PNIPAm is glassy. Regardless of temperature, radial distribution functions showed that water formed clusters with sizes in the range of 0.2–0.4 nm in PU- -PNIPAm. At low water concentrations, more clusters were found in the PU domain but at high water concentrations, more in the PNIPAm domain. It is believed that water molecules diffuse as clusters rather than as individual molecules.

关键词： molecular dynamics simulation     amphiphilic block copolymer     free volume     water diffusivity     fujita model    

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The inactivation of bacteriophages MS2 and PhiX174 by nanoscale zero-valent iron: Resistance difference

《环境科学与工程前沿（英文）》 2022年 第16卷 第8期 doi: 10.1007/s11783-022-1529-4

摘要：

• The resistance of phage PhiX174 to nZVI was much stronger than that of MS2.

关键词： Nanoscale zero-valent iron (nZVI)     MS2     PhiΧ174     Resistance     Inactivation     Pathogenic microorganisms    

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化学键参数和原子半径差与BMG合金的GFA关系

蔡安辉,潘冶,孙国雄

《中国工程科学》 2004年 第6卷 第7期   页码 81-87

摘要：

综合大块金属玻璃（BMG）的研究成果，用加权平均原则计算大块金属玻璃的原子半径差比率Δd、原子电负性差比率Δe以及离子率v三个物理参数，以大块金属玻璃的玻璃形成的临界冷却速度Rc作为合金非晶形成能力（GFA）的参数，用Origin 软件分别对上述三个物理参量与Rc的关系进行统计处理时发现：Δd，Δe，及v与BMG的GFA的关系出现极小值现象，不同合金体系极小值的位置不同；玻璃形成能力强的合金体系，其各个组元的原子百分含量、组元原子之间的半径差以及电负性差三者之间的搭配是和谐的。金属玻璃合金的最优成分范围以及各种添加元素的最佳添加量现象可能与这三个物理参量与Rc之间的极小值现象有关。

关键词： 化学键参数     原子半径差比率     大块金属玻璃     玻璃形成能力     加权平均原则    

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基于到达时间差和到达频率差的多层等梯度声速剖面建模与声学定位 Research Article

詹东洲1,王思甜1,蔡守桂1,郑华荣2,徐文2

《信息与电子工程前沿（英文）》 2023年 第24卷 第1期   页码 164-175 doi: 10.1631/FITEE.2100398

摘要： 利用传感器节点处信号多普勒频移的导数，提出一种新的使用到达时间差（time difference of arrival，TDOA）和到达频率差（frequency difference of arrival

关键词： 水下声学传感器网络；声学定位；声速剖面；到达时间差（TDOA）；到达频率差（FDOA）    

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Identifying combustion intermediates in premixed MTBE/gasoline/oxygen flame probed via synchrotron radiation

YAO Chunde, LI Jing, LI Qi, JI Qing, HUANG Chaoqun, WEI Lixia, WANG Jing, TIAN Zhenyu, LI Yuyang, QI Fei

《能源前沿（英文）》 2007年 第1卷 第1期   页码 79-84 doi: 10.1007/s11708-007-0007-9

摘要： Molecular-beam sampling mass spectrometry (MBMS) combined with tunable synchrotron radiation photoionization technique offers obvious advantages for the study of flame chemistry over other techniques because of the precision measurement of the combustion intermediates and products in flame. In this paper, the results to identify combustion intermediates in low-pressure premixed gasoline/oxygen flame with the synchrotron radiation were reported. Based on the results obtained, the formation process of five products and the difference between gasoline/oxygen and MTBE/gasoline/oxygen flame were emphatically analyzed. The results achieved provide data basis for the analysis of intermediates and radicals in flame, and are helpful to establish the kinetic modeling of gasoline/oxygen and MTBE/gasoline/oxygen flames.

关键词： synchrotron     photoionization technique     chemistry     analysis     difference    

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标题 作者 时间 类型 操作

Three-dimensional finite difference analysis of shallow sprayed concrete tunnels crossing a reverse fault

Masoud RANJBARNIA, Milad ZAHERI, Daniel DIAS

期刊论文

Temperature difference-powered carbon nanotube bearings

Quanwen HOU, Bingyang CAO, Zengyuan GUO

期刊论文

类差分平衡函数的性质及其应用

张文英,李世取

期刊论文

Analysis of the treatment outcomes of esophageal variceal bleeding patients from multiple centers in

WANG Zhiqiang

期刊论文

Synthesis of Intermittent-Motion Linkages with Slight Difference in Length Between Links

CHEN Xin-bo, YU Zhen

期刊论文

温差能与低温海水资源综合利用研究

付强,王国荣,周守为,钟林,张理,余兴勇,杨浦

期刊论文

Spent rechargeable lithium batteries in e-waste: composition and its implications

Xianlai ZENG,Jinhui LI

期刊论文

多星联合定位理论性能分析

Ding WANG,Shuai WEI,Ying WU

期刊论文

The Difference Effect of Environmental Regulation on Two Stages of Technology Innovation in China’s Manufacturing

Bao-long Yuan,Sheng-gang Ren,Xing Hu,Xuan-yu Yang

期刊论文

Application of random set method in a deep excavation: based on a case study in Tehran cemented alluvium

Arash SEKHAVATIAN, Asskar Janalizadeh CHOOBBASTI

期刊论文

Molecular dynamics study of water diffusion in an amphiphilic block copolymer with large difference in

Yang Zhou, Phillip Choi

期刊论文

The inactivation of bacteriophages MS2 and PhiX174 by nanoscale zero-valent iron: Resistance difference

期刊论文

化学键参数和原子半径差与BMG合金的GFA关系

蔡安辉,潘冶,孙国雄

期刊论文

基于到达时间差和到达频率差的多层等梯度声速剖面建模与声学定位

詹东洲1,王思甜1,蔡守桂1,郑华荣2,徐文2

期刊论文

Identifying combustion intermediates in premixed MTBE/gasoline/oxygen flame probed via synchrotron radiation

YAO Chunde, LI Jing, LI Qi, JI Qing, HUANG Chaoqun, WEI Lixia, WANG Jing, TIAN Zhenyu, LI Yuyang, QI Fei

期刊论文