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大中功率节能调速传动的合理电压等级

马小亮

《中国工程科学》 2001年 第3卷 第11期   页码 80-84

摘要：

大中功率风机和泵采用变频调速可节约大量电能，大部分功率在0.2～2 MW范围中。我国现在200 kW以上的电机多是中压，现行中压电网多为10 kV，选用10 kV直接变频从技术和经济角度看都不太合理。由于变频器输入侧都有变压器，因此电机和变频器没有必要和电网一致。文章讨论不同功率段的合理电压等级以及在电机电压和电网电压不同情况下当变频器出现故障时如何实现旁路工作。

关键词： 大中功率     节能调速     合理电压等级     低压变频     中压变频     旁路    

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Uncoupled state space solution to layered poroelastic medium with anisotropic permeability and compressible

Zhiyong AI, Wenze ZENG, Yichong CHENG, Chao WU

《结构与土木工程前沿（英文）》 2011年 第5卷 第2期   页码 171-179 doi: 10.1007/s11709-011-0103-0

摘要： This paper presents an uncoupled state space solution to three-dimensional consolidation of layered poroelastic medium with anisotropic permeability and compressible pore fluid. Starting from the basic equations of poroelastic medium, and introducing intermediate variables, the state space equation usually comprising eight coupled state vectors is uncoupled into two sets of equations of six and two state vectors in the Laplace-Fourier transform domain. Combined with the continuity conditions between adjacent layers and boundary conditions, the uncoupled state space solution of a layered poroelastic medium is obtained by using the transfer matrix method. Numerical results show that the anisotropy of permeability and the compressibility of pore fluid have remarkable influence on the consolidation behavior of poroelastic medium.

关键词： uncoupled state space solution     layered poroelastic medium     three-dimensional consolidation     anisotropic permeability     compressible pore fluid    

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Preparation of solar selective absorbing CuO coating for medium temperature application

HUANG Qunwu, WANG Yiping, LI Jinhua

《化学科学与工程前沿（英文）》 2007年 第1卷 第3期   页码 256-260 doi: 10.1007/s11705-007-0046-0

摘要： A new method of preparing CuO solar selective absorbing coating for medium temperature is presented. After pretreatment, brass was overlaid with CuO by chemical plating. The effects of reactant concentration, reaction temperature and reaction time on the absorptivity of CuO coating were investigated. The optimized condition of preparing CuO coating was obtained. The CuO coating was analyzed with X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). In order to prolong the period of use, the CuO coating was protected by TiO. The experiment shows that the TiO/CuO coating is more heat-resistant, acid-resistant, and wear resistant than CuO coating, without losing absorptivity markedly. The TiO coating can reduce emissivity and protect the CuO coating.

关键词： photoelectron spectroscopy     temperature     pretreatment     absorptivity     microscopy    

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Frontier of continuous structural health monitoring system for short & medium span bridges and condition

Ayaho MIYAMOTO, Risto KIVILUOMA, Akito YABE

《结构与土木工程前沿（英文）》 2019年 第13卷 第3期   页码 569-604 doi: 10.1007/s11709-018-0498-y

摘要： It is becoming an important social problem to make maintenance and rehabilitation of existing short and medium span(10-20 m) bridges because there are a huge amount of short and medium span bridges in service in the world. The kernel of such bridge management is to develop a method of safety(condition) assessment on items which include remaining life and load carrying capacity. Bridge health monitoring using information technology and sensors is capable of providing more accurate knowledge of bridge performance than traditional strategies. The aim of this paper is to introduce a state-of-the-art on not only a rational bridge health monitoring system incorporating with the information and communication technologies for lifetime management of existing short and medium span bridges but also a continuous data collecting system designed for bridge health monitoring of mainly short and medium span bridges. In this paper, although there are some useful monitoring methods for short and medium span bridges based on the qualitative or quantitative information, mainly two advanced structural health monitoring systems are described to review and analyse the potential of utilizing the long term health monitoring in safety assessment and management issues for short and medium span bridge. The first is a special designed mobile loading device(vehicle) for short and medium span road bridges to assess the structural safety(performance) and derive optimal strategies for maintenance using reliability based method. The second is a long term health monitoring method by using the public buses as part of a public transit system (called bus monitoring system) to be applied mainly to short and medium span bridges, along with safety indices, namely, “characteristic deflection” which is relatively free from the influence of dynamic disturbances due to such factors as the roughness of the road surface, and a structural anomaly parameter.

关键词： condition assessment     short & medium span bridge     structural health monitoring(SHM)     long-term data collection     system     maintenance     bridge performance     information technology     loading vehicle(public bus)     in-situ loading    

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大中型水利工程建设管理的实践和体会

张基尧

《中国工程科学》 2011年 第13卷 第8期   页码 22-25

摘要： 水利工程建设是基础设施建设的重要组成部分。加强水利工程建设管理是提高水利投资效益和社会、经济、生态效益的重要途经，是工程管理科学研究的重要内容。文章主要阐述了不同阶段大中型水利工程建设管理的责任主体、管理重点、有效做法和成功案例。

关键词： 大中型水利工程；项目管理；实践体会    

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Liquid metal as energy transportation medium or coolant under harsh environment with temperature below

Yunxia GAO, Lei WANG, Haiyan LI, Jing LIU

《能源前沿（英文）》 2014年 第8卷 第1期   页码 49-61 doi: 10.1007/s11708-013-0285-3

摘要： The current highly integrated electronics and energy systems are raising a growing demand for more sophisticated thermal management in harsh environments such as in space or some other cryogenic environment. Recently, it was found that room temperature liquid metals (RTLM) such as gallium or its alloys could significantly reduce the electronics temperature compared with the conventional coolant, like water, oil or more organic fluid. However, most of the works were focused on RTLM which may subject to freeze under low temperature. So far, a systematic interpretation on the preparation and thermal properties of liquid metals under low temperature (here defined as lower than 0°C) has not yet been available and related applications in cryogenic field have been scarce. In this paper, to promote the research along this important direction and to overcome the deficiency of RTLM, a comprehensive evaluation was proposed on the concept of liquid metal with a low melting point below zero centigrade, such as mercury, alkali metal and more additional alloy candidates. With many unique virtues, such liquid metal coolants are expected to open a new technical frontier for heat transfer enhancement, especially in low temperature engineering. Some innovative ways for making low melting temperature liquid metal were outlined to provide a clear theoretical guideline and perform further experiments to discover new materials. Further, a few promising applied situations where low melting temperature liquid metals could play irreplaceable roles were detailed. Finally, some main factors for optimization of low temperature coolant were summarized. Overall, with their evident merits to meet various critical requirements in modern advanced energy and power industries, liquid metals with a low melting temperature below zero centigrade are expected to be the next-generation high-performance heat transfer medium in thermal managements, especially in harsh environment in space.

关键词： liquid metal     cryogenics     low melting point     thermal management     aircraft     liquid cooling     space exploration    

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Control division of agricultural non-point source pollution at medium-sized watershed scale in Southeast

HUANG Jinliang, HONG Huasheng, ZHANG Luoping

《环境科学与工程前沿（英文）》 2008年 第2卷 第3期   页码 333-339 doi: 10.1007/s11783-008-0035-7

摘要： This paper presents the study carried out for controlling agricultural non-point source pollution (NSP) in a medium-sized watershed covering 1.47 × 10 km in Southeast China using quantitative analysis coupled with geographic information system (GIS), universal soil loss equation (USLE), soil conservation service-curve number (SCS-CN), nutrient loss equations, and annualized agricultural nonpoint source model (AnnAGNPS). Based on the quantitative results derived from GIS and environmental models, five control division units were generated for NSP control in Jiulong River watershed, namely, controlling unit for soil losses, controlling unit for livestock breeding and soil losses, controlling unit for excessive fertilizer use and livestock breeding, controlling unit for soil losses and fertilizer use, and controlling unit for excessive fertilizer use and soil losses. This study proved that integrating GIS with environmental models can be adopted to efficiently evaluate major sources and contributors of NSP, and identify the critical source areas of NSP, which enables adjusting measures to local conditions by further control division units developed through such study for control and management of water quality degradation induced by NSP in the Jiulong River watershed.
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Should medium-sized contractors still implement home-made information technologies on construction sites

Conrad BOTON, Éric ST-PIERRE, Gabriel LEFEBVRE

《工程管理前沿（英文）》 2020年 第7卷 第1期   页码 142-158 doi: 10.1007/s42524-019-0065-9

摘要： Despite the increasing dissemination of the Building Information Modeling (BIM) approach, many firms are still far from BIM and are only starting to adopt information technologies. We conducted an ethnographic action research with an industrial partner that implements information technologies on its construction sites, with a strong preference for home-made applications. Results show that the development of such applications faces difficulties and that multiple iterations and versions are necessary before achieving the expected goals because the required competencies are lacking among internal development teams. Moreover, initial needs evolve considerably throughout the application’s development and evaluation process. However, notwithstanding the difficulties encountered during the different application development phases, the industrial partner believes the decision to be worthwhile because of the desire to have internal control over the project data and the need to consider certain specificities related to business processes.

关键词： small- and medium-sized enterprises     mobile computing     mobile cloud computing     information technology for construction     construction site     ethnographic action research    

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Blockchain-driven supply chain finance solution for small and medium enterprises

Jian LI, Shichao ZHU, Wen ZHANG, Lean YU

《工程管理前沿（英文）》 2020年 第7卷 第4期   页码 500-511 doi: 10.1007/s42524-020-0124-2

摘要： Blockchain has attracted much attention in recent years with the development of cryptocurrency and digital assets. As the underlying technology of cryptocurrency, blockchain has numerous benefits, such as de-centralization, collective maintenance, tamper-resistance, traceability, and anonymity. The potential of the blockchain technology (BT) is widely recognized in the financial field. Although some scholars have proposed the combination of blockchain and supply chain finance (SCF), the details of this combination is rarely mentioned. This study first analyzes the coupling between SCF and blockchain technology. Second, the conceptual framework of blockchain-driven SCF platform (BcSCFP) is presented. Third, the operation process of three SCF models on the BcSCFP is proposed. Finally, a case study combined with actual events is conducted. This paper has a positive practical significance in the operation and management of banks and loan enterprises.

关键词： blockchain technology     supply chain finance     risk management     smart contract     decentralization    

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Effect of seismic wave propagation in massed medium on rate-dependent anisotropic damage growth in concrete

Alireza DANESHYAR, Hamid MOHAMMADNEZHAD, Mohsen GHAEMIAN

《结构与土木工程前沿（英文）》 2021年 第15卷 第2期   页码 346-363 doi: 10.1007/s11709-021-0694-z

摘要： Seismic modeling of massive structures requires special caution, as wave propagation effects significantly affect the responses. This becomes more crucial when the path-dependent behavior of the material is considered. The coexistence of these conditions renders numerical earthquake analysis of concrete dams challenging. Herein, a finite element model for a comprehensive nonlinear seismic simulation of concrete gravity dams, including realistic soil–structure interactions, is introduced. A semi-infinite medium is formulated based on the domain reduction method in conjunction with standard viscous boundaries. Accurate representation of radiation damping in a half-space medium and wave propagation effects in a massed foundation are verified using an analytical solution of vertically propagating shear waves in a viscoelastic half-space domain. A rigorous nonlinear finite element model requires a precise description of the material response. Hence, a microplane-based anisotropic damage–plastic model of concrete is formulated to reproduce irreversible deformations and tensorial degeneration of concrete in a coupled and rate-dependent manner. Finally, the Koyna concrete gravity dam is analyzed based on different assumptions of foundation, concrete response, and reservoir conditions. Comparison between responses obtained based on conventional assumptions with the results of the presented comprehensive model indicates the significance of considering radiation damping and employing a rigorous constitutive material model, which is pursued for the presented model.

关键词： soil–structure interaction     massed foundation     radiation damping     anisotropic damage    

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Seismic experimental study on a concrete pylon from a typical medium span cable-stayed bridge

Yan XU, Shijie ZENG, Xinzhi DUAN, Dongbing JI

《结构与土木工程前沿（英文）》 2018年 第12卷 第3期   页码 401-411 doi: 10.1007/s11709-018-0464-8

摘要：

According to the current seismic design codes of bridges in China, cable-stayed bridges have been usually required to remain elastic even subjected to strong earthquakes. However, the possibilities of pylon plastic behavior were revealed in recent earthquake damages. The lack of due diligence in the nonlinear seismic behavior of the pylon has caused a blurry understanding about the seismic performance of such widely built though less strong earthquake experienced structures. In light of this point, a 1/20 scaled concrete pylon model which from a typical medium span cable-stayed bridge was designed and tested on the shaking table longitudinally. The dynamic response and seismic behavior of the pylon were measured, evaluated and compared to reveal its vulnerable parts and nonlinear seismic performance. The results show that most parts of the concrete pylon remain elastic even under very strong excitations, which means a sufficient safety margin for current pylon longitudinal design. The most vulnerable parts of the pylon appeared first at the pylon bottom region, cracks opening and closing at the pylon bottom were observed during the test, and then extended to the lower column and middle column around the lower strut.

关键词： cable-stayed bridge     pylon     shaking table test     seismic behavior    

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Vibration analysis of medium and small span bridges subjected to mixed marshalling freight trains

LI Qi, WU Dingjun, HUANG Xiaobin

《结构与土木工程前沿（英文）》 2008年 第2卷 第2期   页码 133-138 doi: 10.1007/s11709-008-0019-5

摘要： It has been reported several times that train derailment occurs when mixed marshalling freight trains traverse bridges at high speeds in China. This study aims to explain this phenomenon numerically based on the train-bridge coupling vibration theory and its associated computer program. The train-bridge vibration characteristic is analyzed by a computer program when mixed marshalling freight trains traverse 32-meter-span prestressed concrete simple beam bridges. The mechanism that dynamic responses of the bridges are prominent and that empty trains are inclined to derail are derived from the dynamic responses analysis. The analysis indicates that the significant differences of axle loads between heavy vehicles and empty vehicles produce periodic forced loadings of large amplitudes. These periodic loadings cause severe vibration of bridges. In turn, severe vibration of the bridges produces intensive counteraction to empty vehicles.

关键词： train-bridge vibration     vibration characteristic     associated computer     train-bridge     phenomenon    

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Uncertainty assessment in hydro-mechanical-coupled analysis of saturated porous medium applying fuzzy

Farhoud KALATEH, Farideh HOSSEINEJAD

《结构与土木工程前沿（英文）》 2020年 第14卷 第2期   页码 387-410 doi: 10.1007/s11709-019-0601-z

摘要： The purpose of the present study was to develop a fuzzy finite element method, for uncertainty quantification of saturated soil properties on dynamic response of porous media, and also to discrete the coupled dynamic equations known as - hydro-mechanical equations. Input parameters included fuzzy numbers of Poisson’s ratio, Young’s modulus, and permeability coefficient as uncertain material of soil properties. Triangular membership functions were applied to obtain the intervals of input parameters in five membership grades, followed up by a minute examination of the effects of input parameters uncertainty on dynamic behavior of porous media. Calculations were for the optimized combinations of upper and lower bounds of input parameters to reveal soil response including displacement and pore water pressure via fuzzy numbers. Fuzzy analysis procedure was verified, and several numerical examples were analyzed by the developed method, including a dynamic analysis of elastic soil column and elastic foundation under ramp loading. Results indicated that the range of calculated displacements and pore pressure were dependent upon the number of fuzzy parameters and uncertainty of parameters within equations. Moreover, it was revealed that for the input variations looser sands were more sensitive than dense ones.

关键词： fuzzy finite element method     saturated soil     hydro-mechanical coupled equations     coupled analysis     uncertainty analysis    

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国外中小企业技术创新的做法及启示

梅强,唐祥金

《中国工程科学》 2003年 第5卷 第8期   页码 81-86

摘要：

中小企业中的高新技术企业是技术创新和技术进步的生力军,技术创新是中小企业的生命线。在技术创新向纵深推进的过程中，我国中小企业应借鉴国外的做法及经验，进一步加快发展风险投资业，加大科技投入，加快制度创新，加速构建社会化服务体系。

关键词： 国外中小企业     技术创新     创新环境    

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Behavior of steel fiber–reinforced high-strength concrete at medium strain rate

Chujie JIAO, Wei SUN, Shi HUAN, Guoping JIANG

《结构与土木工程前沿（英文）》 2009年 第3卷 第2期   页码 131-136 doi: 10.1007/s11709-009-0027-0

摘要： Impact compression experiments for the steel fiber–reinforced high-strength concrete (SFRHSC) at medium strain rate were conducted using the split Hopkinson press bar (SHPB) testing method. The volume fractions of steel fibers of SFRHSC were between 0 and 3%. The experimental results showed that, when the strain rate increased from threshold value to 90 s , the maximum stress of SFRHSC increased about 30%, the elastic modulus of SFRHSC increased about 50%, and the increase in the peak strain of SFRHSC was 2-3 times of that in the matrix specimen. The strength and toughness of the matrix were improved remarkably because of the superposition effect of the aggregate high-strength matrix and steel fiber high-strength matrix. As a result, under impact loading, cracks developed in the SFRHSC specimen, but the overall shape of the specimen remained virtually unchanged. However, under similar impact loading, the matrix specimens were almost broken into small pieces.

关键词： steel fiber–reinforced high-strength concrete (SFRHSC)     high strain rates     split Hopkinson press bar (SHPB)     strain rate hardening effects    

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标题 作者 时间 类型 操作

大中功率节能调速传动的合理电压等级

马小亮

期刊论文

Uncoupled state space solution to layered poroelastic medium with anisotropic permeability and compressible

Zhiyong AI, Wenze ZENG, Yichong CHENG, Chao WU

期刊论文

Preparation of solar selective absorbing CuO coating for medium temperature application

HUANG Qunwu, WANG Yiping, LI Jinhua

期刊论文

Frontier of continuous structural health monitoring system for short & medium span bridges and condition

Ayaho MIYAMOTO, Risto KIVILUOMA, Akito YABE

期刊论文

大中型水利工程建设管理的实践和体会

张基尧

期刊论文

Liquid metal as energy transportation medium or coolant under harsh environment with temperature below

Yunxia GAO, Lei WANG, Haiyan LI, Jing LIU

期刊论文

Control division of agricultural non-point source pollution at medium-sized watershed scale in Southeast

HUANG Jinliang, HONG Huasheng, ZHANG Luoping

期刊论文

Should medium-sized contractors still implement home-made information technologies on construction sites

Conrad BOTON, Éric ST-PIERRE, Gabriel LEFEBVRE

期刊论文

Blockchain-driven supply chain finance solution for small and medium enterprises

Jian LI, Shichao ZHU, Wen ZHANG, Lean YU

期刊论文

Effect of seismic wave propagation in massed medium on rate-dependent anisotropic damage growth in concrete

Alireza DANESHYAR, Hamid MOHAMMADNEZHAD, Mohsen GHAEMIAN

期刊论文

Seismic experimental study on a concrete pylon from a typical medium span cable-stayed bridge

Yan XU, Shijie ZENG, Xinzhi DUAN, Dongbing JI

期刊论文

Vibration analysis of medium and small span bridges subjected to mixed marshalling freight trains

LI Qi, WU Dingjun, HUANG Xiaobin

期刊论文

Uncertainty assessment in hydro-mechanical-coupled analysis of saturated porous medium applying fuzzy

Farhoud KALATEH, Farideh HOSSEINEJAD

期刊论文

国外中小企业技术创新的做法及启示

梅强,唐祥金

期刊论文

Behavior of steel fiber–reinforced high-strength concrete at medium strain rate

Chujie JIAO, Wei SUN, Shi HUAN, Guoping JIANG

期刊论文