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瞬态成像；飞行时间（time-of-flight 1

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Transient imaging with a time-of-flight cameraand its applications

Jing-yu LIN, Ri-hui WU, Hong-man WANG, Ye-bin LIU

《信息与电子工程前沿（英文）》 2017年 第18卷 第9期   页码 1268-1276 doi: .org/10.1631/FITEE.1700556

摘要： Transient imaging is a technique in photography that recordsthe process of light propagation before it reaches a stationary statesuch that events at the light speed level can be observed. In thisreview we introduce three main models for transient imaging with atime-of-flight (ToF) camera: correlation model, frequency-domain model,and compressive sensing model. Transient imaging applications usuallyinvolve resolving the problem of light transport and separating thelight rays arriving along different paths. We discuss two of the applications:imaging objects inside scattering media and recovering both the shapeand texture of an object around a corner.

关键词： Transient imaging     Time-of-flight(ToF) camera     Scattering media     Around corners    

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采用飞行时间相机的瞬态成像及其应用

Jing-yu Lin, Ri-hui Wu, Hong-man Wang, Ye-bin Liu,jylin@gxu.edu.cn,liuyebin@tsinghua.edu.cn

《信息与电子工程前沿（英文）》 2017年 第18卷 第9期   页码 1268-1276 doi: 10.1631/FITEE.1700556

摘要： 概要：瞬态成像是一种记录光从开始照射直到稳定状态全过程的摄像技术，这使得光速量级的事件可以被观测。介绍了采用飞行时间（time-of-flight, ToF）相机进行瞬态成像的三种数学模型，即相关函数模型、频域模型和压缩感知模型。瞬态图像应用主要基于光传输解析和不同光路光线分离。讨论了两种应用，即对散射介质内的物体进行成像和恢复被拐角遮挡物体的形状和纹理。

关键词： 瞬态成像；飞行时间（time-of-flight     ToF）；散射介质；拐角遮挡    

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Alluvial channel hydrodynamics around tandem piers with downward seepage

Rutuja CHAVAN, Wenxin HUAI, Bimlesh KUMAR

《结构与土木工程前沿（英文）》 2020年 第14卷 第6期   页码 1445-1461 doi: 10.1007/s11709-020-0648-x

摘要： In this paper, we report the turbulent flow structures and the scour geometry around two piers with different diameters. An experiment was conducted on a non-uniform sand bed with two types of tandem arrangements, namely, pier (T1) with a 75 mm front and 90 mm rear, and pier (T2) with a 90 mm front and 75 mm rear, with and without-seepage flows, respectively. A strong wake region was observed behind the piers, but the vortex strength diminished with downward seepage. Streamwise velocity was found to be maximum near the bed downstream of the piers and at the edge of the scour hole upstream of the piers. Quadrant analysis was used to recognize the susceptible region for sediment entrainment and deposition. Upstream of the piers near the bed, the moments, turbulent kinetic energy (TKE), and TKE fluxes were found to decrease with downward seepage, in contrast to those in a plane mobile bed without piers. The reduction percentages of scour depth at the rear pier compared with the front one were approximately 40% for T1 and 60% for T2. Downward seepage also resulted in restrained growth of scouring with time.

关键词： scour     seepage     Strouhal number     tandem arrangement     turbulent characteristics    

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Numerical modeling of current-induced scour around multi-wall foundation using large-eddy simulation

《结构与土木工程前沿（英文）》 2023年 第17卷 第4期   页码 546-565 doi: 10.1007/s11709-023-0943-4

摘要： Scouring is one of the primary triggers of failure for bridges across rivers or seas. However, research concerning the scour mechanism of multi-wall foundations (MWFs) remains scarce, hindering the further application of MWFs. In this study, for the first time, the scouring effect caused by unidirectional flow around MWFs was examined numerically using FLOW-3D involving a large-eddy simulation. Initially, the applicability of the scouring model and input parameters was validated using a case study based on published measured data. Subsequently, the scouring effects of four MWFs with different wall arrangements and inflow angles, including the flow field analysis and scour pit and depth, were investigated thoroughly. It was found that the maximum scour depth of MWFs with an inflow angle of 0° was smaller than that of those with an inflow angle of 45°, regardless of the wall arrangement. Meanwhile, changing the inflow angle significantly affects the scour characteristics of MWFs arranged in parallel. In practical engineering, MWFs arranged in parallel are preferred considering the need for scouring resistance. However, a comparative analysis should be performed to consider comprehensively whether to adopt the form of a round wall arrangement when the inflow angle is not 0° or the inflow direction is changeable.

关键词： multi-wall foundation     current-induced scour     bridge foundation     large-eddy simulation     numerical analysis    

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Nutrient status and pollution levels in five areas around a manganese mine in southern China

Kehui Liu, Xiaolu Liang, Chunming Li, Fangming Yu, Yi Li

《环境科学与工程前沿（英文）》 2020年 第14卷 第6期 doi: 10.1007/s11783-020-1279-0

摘要： Abstract • The soil TP level was high or extremely high in all areas. • TN, OM and available Cu were insufficient in EA, TA and RA. • All areas reached the heavily polluted level and had high ecological risk levels. • Mn and Cd were the dominant pollutants. Nutrient status and pollution levels are the main factors affecting soil restoration. The nutrient status and pollution levels in five areas, an unexplored mine area (UA), an explored mine area (EA), a tailings area (TA), a reclamation area (RA) and an agricultural area (AA), around the Pingle manganese mine in Guangxi, China, were assessed in this study. The results showed that the average total phosphorus in these five areas ranged from 1.05 to 1.57 mg/kg, corresponding to grades of extremely high and high. The average total nitrogen values were 0.19, 0.69, 0.93, 1.24 and 1.67 mg/kg in EA, TA, RA, UA and AA, corresponding to grades of very low, low, medium-low, medium-high and medium-high, respectively. The average organic matter values were 12.78, 8.92, 22.77, 21.29 and 29.11 mg/kg in EA, TA, RA, UA and AA, which corresponded to grades of medium-low, low, medium-high, medium-high and medium-high, respectively. All these results indicated that the total phosphorus was sufficient in these areas, while the total nitrogen and organic matter were insufficient in EA, TA and RA. The available concentrations of Mn and Zn corresponded to the intermediate grade, while the values for Cu corresponded to the very low grade; these might be another factor restricting ecological reclamation. Contamination and ecological risk assessments based on the single contamination index, Nemerow multi-factor index and potential ecological risk index showed that the five tested areas around the Mn mine were considered heavily polluted and presented high ecological risk. Mn and Cd were the dominant pollutants.

关键词： Ecological reclamation     Ecological risk assessment     Heavy metal     Mn mine     Soil nutrients    

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The temporal changes of the concentration level of typical toxic organics in the river sediments around

Qiang Li, Xiong Xu, Yaoyao Fang, Ruiyang Xiao, Donghong Wang, Wenjue Zhong

《环境科学与工程前沿（英文）》 2018年 第12卷 第6期 doi: 10.1007/s11783-018-1054-7

摘要：

The current situation of typical organics in the sediments around Beijing was unclear.

56 kinds of typical toxic organics were detected in this article.

Historical data was compared with the data in this study.

The change of different organics in the sediments around Beijing was concluded.

关键词： Organic compounds     Endocrine disrupters     Sediments     Concentration     Temporal changes    

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Particle swarm optimization model to predict scour depth around a bridge pier

Shahaboddin SHAMSHIRBAND, Amir MOSAVI, Timon RABCZUK

《结构与土木工程前沿（英文）》 2020年 第14卷 第4期   页码 855-866 doi: 10.1007/s11709-020-0619-2

摘要： Scour depth around bridge piers plays a vital role in the safety and stability of the bridges. The former approaches used in the prediction of scour depth are based on regression models or black box models in which the first one lacks enough accuracy while the later one does not provide a clear mathematical expression to easily employ it for other situations or cases. Therefore, this paper aims to develop new equations using particle swarm optimization as a metaheuristic approach to predict scour depth around bridge piers. To improve the efficiency of the proposed model, individual equations are derived for laboratory and field data. Moreover, sensitivity analysis is conducted to achieve the most effective parameters in the estimation of scour depth for both experimental and filed data sets. Comparing the results of the proposed model with those of existing regression-based equations reveal the superiority of the proposed method in terms of accuracy and uncertainty. Moreover, the ratio of pier width to flow depth and ratio of 50 (mean particle diameter) to flow depth for the laboratory and field data were recognized as the most effective parameters, respectively. The derived equations can be used as a suitable proxy to estimate scour depth in both experimental and prototype scales.

关键词： scour depth     bridge design and construction     particle swarm optimization     computational mechanics     artificial intelligence     bridge pier    

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Perfluorocarboxylic acids (PFCAs) and perfluoroalkyl sulfonates (PFASs) in surface and tap water around

Yong QIU, He JING, Hanchang SHI,

《环境科学与工程前沿（英文）》 2010年 第4卷 第3期   页码 301-310 doi: 10.1007/s11783-010-0236-8

摘要： Perfluorinated compounds (PFCs) are ubiquitously distributed in the environment mainly as perfluoro-carboxylic acids (PFCAs) and perfluoroalkyl sulfonates (PFASs). In this paper, six PFCAs and two PFASs were quantified in surface and tap water samples from 12 sites around Lake Taihu near Shanghai City in East China. Predominant PFCs were perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), of which the concentration ranges were 6.8–206 and 1.2–45 ng·L, the geometric means were 35.3 and 9.4 ng·L, and the median (quartile range) values were 31.4 (34.4) and 10.4 (10.7) ng·L, respectively. Other PFCs were also detected but in much lower concentrations than PFOA. The sources of the PFCs were expected to be direct industrial discharges in the Lake Taihu area, and this area was also a possible source of PFCs contaminations in Shanghai district in the downstream. PFCs distributions were found different in the upstream, downstream and north part of Lake Taihu. Occurrences of PFCs in the tap water in Lake Taihu area indicated their exposure to the local people. A brief estimation of the environmental risks by PFCs implied no acute or immediate risks from PFCs to local human health, but chronic risks from PFOA in the tap water should be considered in the downstream regions.

关键词： surface and tap water     perfluorocarboxylic acids (PFCAs)     perfluoroalkyl sulfonates (PFASs)     Lake Taihu area     ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS)    

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The abundance, characteristics and diversity of microplastics in the South China Sea: Observation around

Hongzhe Chen , Sumin Wang , Huige Guo , Yunlong Huo , Hui Lin , Yuanbiao Zhang

《环境科学与工程前沿（英文）》 2022年 第16卷 第1期   页码 9-9 doi: 10.1007/s11783-021-1443-1

摘要： Surrounded by emerging markets with considerable plastic consumption, the South China Sea has been a focus area of microplastic research. A survey on the floating microplastics (>0.3 mm) and microplastics ingested by fish and mollusks was conducted around three remote islands here. Compared with the results from several previous studies, a high abundance of floating microplastics (with a median of 1.9 × 105 items/km2 or 0.7 items/m3) was observed, revealing another “hot spot” for microplastics. Polyolefin, especially polypropylene, was the main component. The diversity index and evenness index were calculated and evaluated based on the composition of microplastics. The characteristic peaks of Raman spectra concerning pigmented microplastics were provided. Transparent sheets/films were predominant in the water sample, which was quite different from a similar study in this sea area (8.9% for film), and only 16.4% of floating microplastics (>0.3 mm) were fibers/lines, implying that the main sources of floating microplastics (>0.3 mm) might be household/agricultural consumption activities. The transparent fiber/line was also dominant in organisms. It is suggested that the main sources of microplastics ingested by organisms might be both fabric fibers and fishing/aquaculture.
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Modeling of the minimum cutting thickness in micro cutting with consideration of the friction around

Tianfeng ZHOU, Ying WANG, Benshuai RUAN, Zhiqiang LIANG, Xibin WANG

《机械工程前沿（英文）》 2020年 第15卷 第1期   页码 81-88 doi: 10.1007/s11465-019-0561-y

摘要： Friction modeling between the tool and the workpiece plays an important role in predicting the minimum cutting thickness during TC4 micro machining and finite element method (FEM) cutting simulation. In this study, a new three-region friction modeling is proposed to illustrate the material flow mechanism around the friction zone in micro cutting; estimate the stress distributions on the rake, edge, and clearance faces of the tool; and predict the stagnation point location and the minimum cutting thickness. The friction modeling is established by determining the distribution of normal and shear stress. Then, it is applied to calculate the stagnation point location on the edge face and predict the minimum cutting thickness. The stagnation point and the minimum cutting thickness are also observed and illustrated in the FEM simulation. Micro cutting experiments are conducted to validate the accuracy of the friction and the minimum cutting thickness modeling. Comparison results show that the proposed friction model illustrates the relationship between the normal and sheer stress on the tool surface, thereby validating the modeling method of the minimum cutting thickness in micro cutting.

关键词： tool friction     minimum cutting thickness     finite element method     tool edge radius     micro cutting    

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Long-term settlement behavior of ground around shield tunnel due to leakage of water in soft deposit

Huaina WU, Yeshuang XU, Shui-long SHEN, Jin-chun CHAI

《结构与土木工程前沿（英文）》 2011年 第5卷 第2期   页码 194-198 doi: 10.1007/s11709-011-0105-y

摘要： The lining of shield tunnel is usually composed of segments, in which the joints, cracks, and the grouting holes (hereafter called lining deficit) exist. During the long-term running, soils and groundwater may leak from these kinds of lining deficit. The leaking of soil and groundwater causes the long-term ground loss around tunnel and thus results in the settlement of ground surface. This paper aims to analyze the impact of the leakage of groundwater through segments on the long-term settlement of ground surface. The adopted analytical method is based on the theory of groundwater seepage by using numerical simulation. The analyzed results show that settlement of ground surface increases gradually with the increase of the leaked volume of tunnel segments. When the leaked volume was unevenly distributed, differential settlement occurred locally. Comparative analysis by changing the leaked volume was conducted. The results reveal that there is a linear relationship between settlement and leaked volume when the leaked volume was controlled within the allowable limit.

关键词： lining deficit     leakage of water     shield tunnel     settlement     soft deposit    

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Tuned reactive power dispatch through modified differential evolution technique

S. BISWAS (RAHA), N. CHAKRABORTY

《能源前沿（英文）》 2012年 第6卷 第2期   页码 138-147 doi: 10.1007/s11708-012-0188-8

摘要： This paper explores the capability of modified differential evolution (MDE) technique for solving the reactive power dispatch (RPD) problem. The proposed method is based on the basic differential evolution (DE) technique with a few modifications made into it. DE is one of the strongest optimization techniques though it suffers from the problem of slow convergence while global minima appear. The proposed modifications are tried to resolve the problem. The RPD problem mainly defines loss minimization with stable voltage profile. To solve the RPD problem, the generator bus voltage, transformer tap setting and shunt capacitor placements are controlled by the MDE approach. In this paper, IEEE 14-bus and IEEE 30-bus systems are chosen for MDE implementation. The applied modification show much improved result in comparison to normal DE technique. Comparative study with other soft-computing technique including DE validates the effectiveness of the proposed method.

关键词： reactive power dispatch (RPD)     modified differential evolution (MDE)     differential evolution algorithm with localizations around the best vector (DELB)    

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秦巴山脉周边城市地区协同发展研究

周庆华,牛俊蜻

《中国工程科学》 2016年 第18卷 第5期   页码 10-16 doi: 10.15302/J-SSCAE-2016.05.002

摘要：

秦巴山脉周边城市地区位于我国地理中心，涉及成渝城市群、关中城市群、武汉城市群、中原城市群等多个城市集聚区。在我国当前进入“一带一路”、多边开放的战略背景下，其内部城市之间的协同发展对于支撑中西部崛起、保护秦巴山脉生态环境、带动山区连片贫困地区进入小康社会具有重要意义。由于内部各城市群之间物理空间跨度较大，所以当前秦巴山脉周边城市地区经济联系较弱。本文在借鉴国内外相关研究与实践的基础上，考虑到未来新经济要素对空间距离作用的消减，从宏观格局判断、空间可能模式、快速交通联系、产业分工协作四个方面着手，对秦巴周边城市地区的协同发展路径进行探讨。

关键词： 秦巴山脉     城市地区     协同发展    

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全球主要国家和地区网络电子身份管理发展与应用

胡传平,陈兵,方滨兴、邹翔

《中国工程科学》 2016年 第18卷 第6期   页码 99-103 doi: 10.15302/J-SSCAE-2016.06.020

摘要：

本文对世界主要国家和地区网络电子身份管理的最新进展、典型应用以及我国网络电子身份管理与应用等情况进行了全面的分析与梳理，并结合网络身份管理技术的发展趋势，提出“十三五”期间我国网络电子身份管理的发展思路和建设性意见，旨在加强网络空间身份管理，构建网络空间身份管理体系，同时有助于规范网民行为、防范打击网络犯罪、构建网络强国、维护国家安全和网络空间主权、保护网络用户的个人隐私，以期为“十三五”期间我国网络身份管理发展提供借鉴和参考。

关键词： 网络电子身份     身份管理     数字签名    

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世界范围内网络主权的主要观点综述

朱诗兵,张学波,王宇

《中国工程科学》 2016年 第18卷 第6期   页码 89-93 doi: 10.15302/J-SSCAE-2016.06.018

摘要：

网络空间在给我们生活带来极大便利的同时，也带来了诸多新的问题和挑战，网络主权是解决网络空间发展带来的国家利益冲突的基本原则。本文归纳分析了当前世界范围内对网络主权持赞同、反对和认为不重要的三种观点，并对重要的国际组织和世界主要国家对网络主权的态度进行了综述，以期达到对网络主权现状的客观认识。

关键词： 网络空间     国家主权     网络主权     多利益攸关方     信息通信技术活动    

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标题 作者 时间 类型 操作

Transient imaging with a time-of-flight cameraand its applications

Jing-yu LIN, Ri-hui WU, Hong-man WANG, Ye-bin LIU

期刊论文

采用飞行时间相机的瞬态成像及其应用

Jing-yu Lin, Ri-hui Wu, Hong-man Wang, Ye-bin Liu,jylin@gxu.edu.cn,liuyebin@tsinghua.edu.cn

期刊论文

Alluvial channel hydrodynamics around tandem piers with downward seepage

Rutuja CHAVAN, Wenxin HUAI, Bimlesh KUMAR

期刊论文

Numerical modeling of current-induced scour around multi-wall foundation using large-eddy simulation

期刊论文

Nutrient status and pollution levels in five areas around a manganese mine in southern China

Kehui Liu, Xiaolu Liang, Chunming Li, Fangming Yu, Yi Li

期刊论文

The temporal changes of the concentration level of typical toxic organics in the river sediments around

Qiang Li, Xiong Xu, Yaoyao Fang, Ruiyang Xiao, Donghong Wang, Wenjue Zhong

期刊论文

Particle swarm optimization model to predict scour depth around a bridge pier

Shahaboddin SHAMSHIRBAND, Amir MOSAVI, Timon RABCZUK

期刊论文

Perfluorocarboxylic acids (PFCAs) and perfluoroalkyl sulfonates (PFASs) in surface and tap water around

Yong QIU, He JING, Hanchang SHI,

期刊论文

The abundance, characteristics and diversity of microplastics in the South China Sea: Observation around

Hongzhe Chen , Sumin Wang , Huige Guo , Yunlong Huo , Hui Lin , Yuanbiao Zhang

期刊论文

Modeling of the minimum cutting thickness in micro cutting with consideration of the friction around

Tianfeng ZHOU, Ying WANG, Benshuai RUAN, Zhiqiang LIANG, Xibin WANG

期刊论文

Long-term settlement behavior of ground around shield tunnel due to leakage of water in soft deposit

Huaina WU, Yeshuang XU, Shui-long SHEN, Jin-chun CHAI

期刊论文

Tuned reactive power dispatch through modified differential evolution technique

S. BISWAS (RAHA), N. CHAKRABORTY

期刊论文

秦巴山脉周边城市地区协同发展研究

周庆华,牛俊蜻

期刊论文

全球主要国家和地区网络电子身份管理发展与应用

胡传平,陈兵,方滨兴、邹翔

期刊论文

世界范围内网络主权的主要观点综述

朱诗兵,张学波,王宇

期刊论文