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The rebound effect of dematerialization and decoupling:a case of energy efficiency

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Chinese Journal of Population,Resources and Environment 2018年第4期16卷 299-313页

作者： Qinglong Shao lei rao College of Civil Engineering Shenzhen University School of Economics Sichuan University

The two essential terms in environmental sciences-dematerialization and decoupling-have always been controversial. This study aims to trace the evolution path on the methodologies, the evidences and the policies, and to reflect on the implications of the development. We specifically present several classical definitions so as to summarize the similarities and differences thereinafter. Several commonly used methodologies, which are employed for evaluating the levels of dematerialization and decoupling, are discussed. As expected, the empirical evidences rarely support the absolute dematerialization and decoupling, which challenge the relevant policies implemented worldwide. In this context, the rebound effect, which is regarded as the main obstacle, is necessary to be examined in the various sectors and areas. However, the results of the rebound levels are far from unanimous. This article has a further discussion on the possible direction for the inconclusive debate in a broader perspective.

关键词： Dematerialization decoupling rebound effect

Sampling visual SLAM with a wide-angle camera for legged mobile robots

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IET Cyber-Systems and Robotics 2022年第4期4卷 356-375页

作者： Guangyu Fan Jiaxin Huang Dingyu Yang lei rao School of Electronic Information Shanghai DianJi UniversityShanghaiChina Alibaba Group HangzhouChina

Precise localisation and navigation are the two most important tasks for mobile *** simultaneous localisation and mapping(VSLAM)is useful in localisation systems of mobile *** wide-angle camera has a broad field of vision and more abundant information on images,so it is widely used in mobile robots,including legged ***,wide-angle cameras are more complicated than ordinary cameras in the design of visual localisation systems,and higher requirements and challenges are put forward for VSLAM technologies based on wide-angle *** order to resolve the problem of distortion in wide-angle images and improve the accuracy of localisation,a sampling VSLAM based on a wide-angle camera model for legged mobile robots is *** the predictability of the periodic motion of a legged robot,in the method,the images are sampled periodically,image blocks with clear texture are selected and the image details are enhanced to extract the feature points on the ***,the feature points of the blocks are extracted and by using the feature points of the blocks in the images,the feature points on the images are ***,the points on the incident light through the normalised plane are selected as the template points;the relationship between the template points and the images is established through the wide-angle camera model,and the pixel coordinates of the template points in the images and the descriptors are ***,many experiments are conducted on the TUM datasets with a quadruped *** experimental results show that the trajectory error and translation error measured by the proposed method are reduced compared with the VINS-MONO,ORB-SLAM3 and Periodic SLAM systems.

关键词： BRIEF descriptor legged mobile robots ORB-SLAM3 VSLAM wide-angle cameras

The coupling between hydrodynamic and purification efficiencies of ecological porous spur-dike in field drainage ditch

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Journal of Hydrodynamics 2018年第3期30卷 373-383页

作者： lei rao Pei-fang Wang Qing-song Dai Chao Wang College of Mechanics and Materials Hohai University Nanjing 211100 China Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes Ministry of Education Hohai University Nanjing 210098 China College of Environment Hohai University Nanjing 210098 China

In this study, a series of ecological porous spur-dikes are arranged in an experiment channel to simulate a real field drainage ditch. The inside and outside flow fields of spur-dikes are determined by numerical simulations and experimental methods. An Ammonia-Nitrogen（NH3-N） degradation evaluation model is built to calculate the pollution removal rate by coupling with the inner flow field of the porous spur-dikes. The variations of the total pollutant removal rate in the channel are discussed in terms of different porosities and gap distances between spur-dikes and inlet flow velocities. It is indicated that a reasonable parameter matching of the porosity and the gap distance with the flow velocity of the ditch can bring about a satisfactory purification efficiency with a small delivery quantity of ecological porous materials.

关键词： Porous water permeable material ecological spur-dike field drainage ditch pollutant removal rate coupling

Photocatalytic properties of P25-doped TiO_2 composite film synthesized via sol–gel method on cement substrate

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Journal of Environmental Sciences 2018年第4期30卷 71-80页

作者： Xiang Guo lei rao Peifang Wang Chao Wang Yanhui Ao Tao Jiang Wanzhong Wang Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes Ministry of Education College of EnvironmentHohai University College of Mechanics and Materials Hohai University

TiO2 films have received increasing attention for the removal of organic pollutants via photocatalysis. To develop a simple and effective method for improving the photodegradation efficiency of pollutants in surface water, we herein examined the preparation of a P25-TiO2 composite film on a cement substrate via a sol–gel method. In this case, Rhodamine B（Rh B）was employed as the target organic pollutant. The self-generated TiO2 film and the P25-TiO2 composite film were characterized by X-ray diffraction（XRD）, N2 adsorption/desorption measurements, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, and diffuse reflectance spectroscopy（DRS）. The photodegradation efficiencies of the two films were studied by Rh B removal in water under UV（ultraviolet） irradiation. Over 4 day exposure, the P25-TiO2 composite film exhibited higher photocatalytic performance than the self-generated TiO2 film. The photodegradation rate indicated that the efficiency of the P25-TiO2 composite film was enhanced by the addition of the rutile phase Degussa P25 powder. As such, cooperation between the anatase TiO2 and rutile P25 nanoparticles was beneficial for separation of the photo-induced electrons and holes. In addition, the influence of P25 doping on the P25-TiO2 composite films was evaluated. We found that up to a certain saturation point, increased doping enhanced the photodegradation ability of the composite film. Thus, we herein demonstrated that the doping of P25 powders is a simple but effective strategy to prepare a P25-TiO2 composite film on a cement substrate, and the resulting film exhibits excellent removal efficiency in the degradation of organic pollutants.

关键词： P25-TiO2composite film Doping Photocatalysis Sol–gel method Cement substrate Rhodamine B

Experimental and Simulation Studies on Fabricating GCr15/40Cr Bimetallic Compound Rollers Using Electroslag Surfacing with Liquid Metal Method

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Journal of Iron and Steel Research International 2014年第9期21卷 869-877页

作者： lei rao Shuang-jun WANG Jian-hua ZHAO Mao-peng GENG Gang DING College of Mechanical and Electronic Engineering Hohai University College of Mechanical and Electronic Engineering Nanchang University Xinya Special Steel Forging Co. Ltd.

Electroslag surfacing with liquid metal （ESSLM） is an excellent method for producing high quality bimetallic compound rollers. The quality of each compound roller is primarily determined by the metallurgical quality of the combined interface. A GCrl5/40Cr compound roller is produced using an ESSLM non-consumable electrode electro- slag heating method. The temperature and electric fields produced by the ESSLM system are calculated. As the roller core moves downward in the mold, it passes through five sections., the preheating section, the rapid heating section, the temperature homogenizing section, the bimetal fusing section and the cooling section which listed from the top to bottom of the mold, respectively. The temperature distribution and the degree of the surface temperature fluctuation in the roller core are different for each section. Near the combined interface, four layers are found from the roller core to the cladding layer= the remelting layer, the fusion layer, the interface solidification layer and the chilling layer, re spectively. Among these, the fusion and interface solidification layers are the key transition zones that greatly influ- ence the combination quality. The surface temperature of the roller core prior to cladding is mainly determined by the drawing velocity, and the thickness of the transition layer increases as the drawing velocity decreases. A transition layer that is too thick or too thin will reduce the mechanical properties at the combined interface. Therefore, the drawing velocity should be limited to a moderate range to produce a satisfactory bimetallic Compound roller.

关键词： bimetallic compound roller ESSLM combined interface drawing velocity numerical simulation

Macro-and Microstructure Evolution of 5CrNiMo Steel Ingots during Electroslag Remelting Process

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Journal of Iron and Steel Research International 2014年第7期21卷 644-652页

作者： lei rao Jian-hua ZHAO Zhan-xi ZHAO Gang DING Mao-peng GENG College of Mechanical and Electronic Engineering Hohai University Xinya Special Steel Forging Co. Ltd. College of Mechanical and Electronic Engineering Nanchang University

A comprehensive mathematical model was established and used to simulate the macro and microstructure evolution during the production process of 5CrNiMo steel ingot by electroslag remelting （ESR） method. Along the ingot height, the macrostructure distribution characteristics changed from vertical, fine columnar grains to tilted, coarse columnar grains, and this transformation process occurred at the very beginning of ESR. In the cross section of the ingot, there were three grain morphology regions and two grain type transition regions from the outside to the center of the ingot. These regions were the fine columnar grain region, columnar competitive growth transition re gion, coarse columnar grain region, columnar to equiaxed grain transition （CET） region, and coarse equiaxed grain region. The influence of the remelting rate on the macrostructure and mlcrostructure was investigated using a series of experiments and simulations. The results showed that a low remelting rate could produce a small grain growth angle （GGA） ; the average secondary dendrite arm spacing （SDAS） firstly decreased and then increased as the remelting rate increased. An excessively high or low remelting rate can increase the GGA and average SDAS in ingots. Thus, the remelting rate should be controlled within a suitable range to reduce composition microsegregation and microshrinkage in the ingot to produce an ESR ingot with satisfactory hot forging performance.

关键词： electroslag remelting macrostructure microstructure remelting rate secondary dendrite arm spacing

Influence of artificial ecological floating beds on river hydraulic characteristics

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Journal of Hydrodynamics 2014年第3期26卷 474-481页

作者：饶磊钱进敖燕辉 College of Mechanical and Electronic Engineering Hohai University Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes Ministry of EducationCollege of Environment Hohai University

The artificial ecological floating bed is widely used in rivers and lakes to repair and purify polluted water. However, the water flow pattern and the water level distribution are significantly changed by the floating beds, and the influence on the water flow is different from that of aquatic plants. In this paper, based on the continuous porous media model, a moveable two-layer combination model is built to describe the floating bed. The influences of the floating beds on the water flow characteristics are studied by numerical simulations and experiments using an experimental water channel. The variations of the water level distribution are discussed under conditions of different flow velocities（ v= 0.1 m/s, 0.2 m/s, 0.30 m/s, 0.4 m/s）, floating bed coverage rates（20%, 40%, 60%） and arrangement positions away from the channel wall（ D= 0 m, 0.1 m, 0.2 m）. The results indicate that the flow velocity increases under the floating beds, and the water level rises significantly under high flow velocity conditions in the upstream region and the floating bed region. In addition, the average rising water level value（ARWLV） increases significantly with the increase of the floating bed coverage rate, and the arrangement position of floating beds in the river can also greatly influence the water level distribution under a high-flow velocity condition（v ？0.2 m /s）.

关键词： ecological floating bed flow pattern rising water level numerical simulation

Characteristics and mechanism of Leuconostoc citreum as a novel bioflocculant for starch granules in starch production

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Food Innovation and Advances 2023年第4期2卷 291-301页

作者： Xuan Wang Pamela Owusu Osei lei rao Xiaomeng Wu Xiaojun Liao College of Food Science and Nutritional Engineering National Engineering Research Center for Fruit&Vegetable ProcessingKey Laboratory of Fruit&Vegetable ProcessingMinistry of Agriculture and Agricultural AffairsBeijing Key Laboratory for Food Non-thermal ProcessingChina Agricultural UniversityBeijing 100083China

The Leuconostoc citreum SJ-57 strain isolated from the sweet potato starch production showed great potential as a microbiological flocculant,but its underlying flocculation mechanisms are yet *** this study,infrared spectroscopy and thermodynamic analysis were performed to elucidate the short-range and long-range interactions between *** SJ-57 and starch granules,revealing that bacteria cells bond starch granules via metal-bridging ionic bonds.A high repulsive energy barrier of~8×10^(−18)J must be overcome to initiate the flocculation ***,protease,lipase,lysozyme,dextranase,and guanidine hydrochloride were used to treat the bacterial cell,confirming that its flocculation ability originated from surface proteins,including GW structural domain proteins,DnaK,GroEL,elongation factor Tu,and lysozyme *** primary flocculation mechanisms of *** was proposed to provide a deep understanding of microbiological flocculants and a foundation for future industrial applications in starch production.

关键词： starch overcome originated

AM0光谱下三结太阳能电池的温度及聚光特性

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浙江大学学报（工学版） 2015年第12期49卷 2269-2275页

作者：饶蕾计春雷上海电机学院电子工程系上海200240 上海电机学院计算机科学系上海200240

基于目前广泛使用的单二极管等效电路模型建立三结太阳能电池的仿真模型.以Spectrolab公司的ITJ三结GaInP2/GaInAs/Ge太阳能电池为例,在AM0光谱下,采用黑体辐射理论计算得到各子结电池的短路电流密度,代入该仿真模型计算得到电压-负载... 详细信息

基于目前广泛使用的单二极管等效电路模型建立三结太阳能电池的仿真模型.以Spectrolab公司的ITJ三结GaInP2/GaInAs/Ge太阳能电池为例,在AM0光谱下,采用黑体辐射理论计算得到各子结电池的短路电流密度,代入该仿真模型计算得到电压-负载电流密度曲线和电压-输出功率曲线.经过对比发现,理论计算结果与Spectrolab公司实验测试得到的ITJ三结太阳能电池的输出性能曲线结果相一致.基于该仿真模型及Spectrolab公司公布的各材料参数值可以计算得到太阳能电池工作在不同温度和聚光条件下的输出特性.从太阳能电池的开路电压来看,随着温度的升高,开路电压下降,而随着聚焦因子的增大,开路电压上升.从太阳能电池的光电转换效率来看,当聚焦因子从1增大到400时,电池转换效率上升,而聚焦因子进一步增大到1 000时,电池转换效率略有下降.结果表明:在温度为28℃、聚光因子为400左右时,ITJ三结太阳能电池在AM0光谱下的光电转换效率达到最大值30.88%.通过该仿真模型可以预测Spectrolab公司的ITJ三结太阳能电池工作在太空中各种环境下的输出性能参数,对空间飞行器的电源系统设计提供可靠数据支持.

关键词：三结太阳能电池等效电路模型黑体辐射聚焦因子温度系数