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Science China(Technological Sciences) 2015年第7期58卷 1280-1288页

作者： dING Yun XIAO Yang zhong deYu State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University College of Water Conservancy and Hydropower Engineering Hohai University State Key Laboratory of Hydroscience and Engineering Tsinghua University

Resuspension of bed materials absorbing pollutants potentially poses unpredictable challenges to water management in alluvial rivers and its mechanism of transport has not been widely *** this study,a transport equation that defines the movement of pollutants adsorbed on the bed materials in the active bed layer is established,on the basis of mass conservation law and continuum *** transport equation is coupled into the 1-d mathematical model to numerically investigate water pollution process due to the scour of the bed sediment adsorbing *** with the situation in which the dynamics of the active bed layer is not considered indicate that the periodical evolution of the bed layer plays an innegligible role in the pollution process due to sediment ***,comparisons of the results with available experimental observations are presented,and fairly good agreement is obtained.

关键词： resuspension pollutants alluvial rivers active bed layer

WALL EFFECTS ON FLOWS PAST TWO TANdEM CYLINdERS OF dIFFERENT dIAMETERS

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Journal of Hydrodynamics 2012年第1期24卷 1-10页

作者： JIANG Ren-jie LIN Jian-zhong State Key Laboratory of Fluid Power Transmission and Control Zhejiang UniversityHangzhou 310027China China Jiliang University Hangzhou 310018China

Flows past two tandem cylinders of different diameters placed centrally in a channel with fixed centre-to-centre spacing 6d and diameter ratio are simulated based on the Lattice Boltzmann Method（LBM）.In all the simulations,the diameter of the smaller cylinder is chosen as the characteristic *** Reynolds number based on the average inflow velocity is 20-120 and studies are over the range of blockage ratio *** both Small-Big Arrangement（SBA）and Big-Small Arrangement（BSA）,the effects of the channel width and Reynolds number on the flow structures and force coefficients are *** show that the flows in BSA are more regular than those in SBA for the same flow *** BSA with and,the force coefficients all fluctuate with constant amplitudes and a coupled frequency,the coupled frequency becomes small as the blockage ratio decreases and by an exact test we give out the relation of the blockage ratio and Strouhal *** the blockage ratio decreases to 2,there exist pitchfork bifurcations in both SBA and BSA,and results show that the critical Reynolds numbers of pitchfork bifurcations for SBA and BSA are both between 60 and *** SBA with,the flow structure has a static asymmetric *** is found that the channel width has also an effect on the critical spacing where the flow changes from single body mode into co-shedding *** an accurate survey on flows past two cylinders with equal diameters placed inside a channel with the width,the relation between channel width and the critical spacing is given and results show that the critical spacing increases as the channel width increases.

关键词： two tandem cylinders different diameters blockage ratio critical spacing Lattice Boltzmann Method(LBM)

Reactive oxygen species metabolism during the cadmium hyperaccumulation of a new hyperaccumulator Sedum alfredii (Crassulaceae)

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Journal of Environmental Sciences 2007年第11期19卷 1311-1317页

作者： ZHANG zhong-chun QIU Bao-sheng College of Life Sciences Huazhong Normal University Wuhan 430079 China

Sedum alfredii Hance, a newly discovered hyperaccumulator, could serve as a good material for phytoremediation of Cd polluted sites. Malondialdehyde （MdA）, reactive oxygen species （ROS） and antioxidases （catalase （CAT）; superoxide dismutase （SOd）; peroxidase （POd）） in the leaf were determined when S. alfredii was treated for 15 d with various CdC12 concentrations ranging from 0 to 800 μmol/L. The results showed that the production rate of 2＇,7＇-dichlorofluorescein （dCF）, which is an indicator of ROS level, reached up to the maximum at 400 μmol/L CdCl2 and then declined with the increase of CdCl2 concentration, while MdA accumulation tended to increase. CAT activity was significantly inhibited at all tested CdCl2 concentrations and SOd activity was sharply suppressed at 800 μmol/L CdCl2. However, the enhancement of POd activity was observed when CdCl2 concentration was higher than 400 μmol/L. In addition, its activity increased when treated with 600 μmol/L CdCl2 for more than 5 d. When sodium benzoate, a free radical scavenger, was added, S. alfredii was a little more sensitive to Cd toxicity than that exposed to Cd alone, and the Cd accumulation tended to decline with the increase of sodium benzoate concentration. It came to the conclusions that POd played an important role during Cd hyperaccumulation, and the accumulation of ROS induced by Cd treatment might be involved in Cd hyperaccumulation.

关键词： cadmium hyperaccumulation reactive oxygen species Sedum alfredii

Recent advancements in 2d nanomaterials for cancer therapy

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Science China Chemistry 2018年第10期61卷 1214-1226页

作者： Menghuan Li zhong Luo Yanli Zhao division of Chemistry and Biological Chemistry School of Physical and Mathematical Sciences Nanyang Technological University College of Life Science Chongqing University School of Materials Science and Engineering Nanyang Technological University

Since mechanical exfoliation of graphene in 2004, unprecedented scientific and technological advances have been achieved in the development of two-dimensional(2 d) nanomaterials. These 2 d nanomaterials exhibit various unique mechanical, physical and chemical properties on account of their ultrathin thickness, which are highly desirable for many applications such as catalysis, optoelectronics, energy storage/conversion, as well as disease diagnosis and therapeutics. In this review, we summarized recent progress on the design and fabrication of functional 2 d nanomaterials capable of being applied for the cancer treatment including drug delivery, photodynamic therapy, and photothermal therapy. Their anticancer mechanisms were discussed in detail, and the related safety concerns were analyzed based on current research developments. This review is expected to provide an insight in the field of 2 d nanostructured materials for anticancer applications.

关键词： 2d nanomaterials cancer therapy drug delivery photodynamic therapy photothermal therapy

Theoretical Studies on the Isomerization of Peroxynitrite to Nitrate Mediated by Peroxynitrous Acid

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Chinese Journal of Structural Chemistry 2008年第2期27卷 171-176页

作者： LIU Yong-dong zhong Ru-Gang College of Life Science ＆ Bioengineering Beijing University of Technology Beijing 100022 China

The conversion of peroxynitrite （ONOO-） to nitrate （NO3-） mediated by peroxynitrous acid （ONOOH） has been investigated at the CCSd/6-311G（d）//B3LYP/6-31 1＋G（d,p） level. Two kinds of pathways for the title reaction were found. The results show that the energy barrier of isomerization through pathway 1 is around 25 kcal/mol in the gas phase. This value is significantly lower than that of isomerization without any catalysts. Thus, it indicates that ONOOH definitely makes the conversion from ONOO- to NO3- feasible. Although pathway 2 does not decrease the energy barrier of this isomerization, peroxynitric acid （O2NOOH） was obtained; moreover, this is a new pathway for this formation. In view of the results that peroxynitrate anion can decompose into nitrite and dioxygen, we conclude that our results are consistent with the experimental observation that nitrate, nitrite, and dioxygen are the main final products of the decay of peroxynitrite around pH 7.

关键词： peroxynitrite peroxynitrous acid isomerization dFT

A Model for Predicting dynamic Cutting Forces in Sand Mould Milling with Orthogonal Cutting

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Chinese Journal of Mechanical Engineering 2018年第6期31卷 95-105页

作者： zhong-de Shan Fu-Xian Zhu State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science TechnologyBeijing 100083China Jiangsu University of Technology Changzhou 213001China

Cutting force is one of the research hotspots in direct sand mould milling because the cutting force directly a ects the machining quality and tool wear. Unlike metals, sand mould is a heterogeneous discrete deposition material. There is still a lack of theoretical research on the cutting force. In order to realize the prediction and control of the cut?ting force in the sand mould milling process, an analytical model of cutting force is proposed based on the unequal division shear zone model of orthogonal cutting. The deformation velocity relations of the chip within the orthogonal cutting shear zone are analyzed first. According to the flow behavior of granular, the unequal division shear zone model of sand mould is presented, in which the governing equations of shear strain rate, strain and velocity are estab?lished. The constitutive relationship of quasi?solid–liquid transition is introduced to build the 2d constitutive equation and deduce the cutting stress in the mould shear zone. According to the cutting geometric relations of up milling with straight cutting edge and the transformation relationship between cutting stress and cutting force, the dynamic cutting forces are predicted for di erent milling conditions. Compared with the experimental results, the predicted results show good agreement, indicating that the predictive model of cutting force in milling sand mould is validated. Therefore, the proposed model can provide the theoretical guidance for cutting force control in high e ciency mill?ing sand mould.

关键词： Green manufacture Cutting force Sand mould milling Orthogonal cutting Quasi?solid–liquid transition

A Nested-Polymerase Chain Reaction Assay to Identify and Genotype Brucella

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Biomedical and Environmental Sciences 2021年第3期34卷 227-231页

作者： TIAN Guo zhong National Institute for Communicable disease Control and Prevention Chinese Center for Disease Control and PreventionBeijing 102206China

Brucella is gram-negative,facultative,intracellular bacteria implicated in infectious zoonosis diseases,particularly among domestic animals,that are also transmittable to *** genus Brucella is classified based on the ... 详细信息

关键词： Chain Nested transmit

Motion and orientation of cylindrical and cubic particles in pipe flow with high concentration and high particle to pipe size ratio

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第5期9卷 664-671页

作者： Xiao-ke KU Jian-zhong LIN department of Mechanics Zhejiang University Hangzhou 310027 China College of Metrology Technology and Engineering China Jiliang University Hangzhou 310018 China

Lattice Boltzmann method was used to numerically investigate the motion and orientation distribution of cylindrical and cubic particles in pipe flow with high concentration and high particle to pipe size ratio. The transient impulse model of 3d collisions between particles and between particle and wall is proposed. The numerical results are qualitatively in agreement with and quantitatively comparable to the experiment data. The results show that the increases of both the cylindrical particle to pipe size ratio and the particle aspect ratio decrease the rotation about all axes. All rotations of cubic particles decrease with increasing the particle concentration. The cubic particles, rotating more drastically in the flow with large Reynolds number, rotate faster than the cylindrical particles with the same size. The cylindrical particles align with the flow direction more obviously with decreasing Reynolds numbers. However, the orientations of cubic particles are spread all over the range with no significant difference in magnitude, and the Reynolds numbers have no obvious effect on the orientations of cubic particles.

关键词： Particulate flow Angular velocity Orientation Lattice Boltzmann method

Survey of recent progress in semantic image segmentation with CNNs

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Science China(Information Sciences) 2018年第5期61卷 107-124页

作者： Qichuan GENG zhong ZHOU Xiaochun CAO State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and Engineering Beihang University State Key Laboratory of Information Security Institute of Information EngineeringChinese Academy of Sciences

In recent years, convolutional neural networks(CNNs) are leading the way in many computer vision tasks, such as image classification, object detection, and face recognition. In order to produce more refined semantic image segmentation, we survey the powerful CNNs and novel elaborate layers, structures and strategies, especially including those that have achieved the state-of-the-art results on the Pascal VOC 2012 semantic segmentation challenge. Moreover, we discuss their different working stages and various mechanisms to utilize the structural and contextual information in the image and feature spaces. Finally, combining some popular underlying referential methods in homologous problems, we propose several possible directions and approaches to incorporate existing effective methods as components to enhance CNNs for the segmentation of specific semantic objects.

关键词： semantic image segmentation CNN Pascal VOC 2012 challenge multi-granularity features construction of contextual relationships

Automation of diffusion database development in multicomponent alloys from large number of experimental composition profiles

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npj Computational Materials 2021年第1期7卷 320-332页

作者： Jing zhong Li Chen Lijun Zhang State Key Laboratory of Powder Metallurgy Central South UniversityChangshaHunanChina Shenzhen Research Institute Central South UniversityShenzhenChina

Nowadays,the urgency for the high-quality interdiffusion coefficients and atomic mobilities with quantified uncertainties in multicomponent/multi-principal element alloys,which are indispensable for comprehensive understanding of the diffusioncontrolled processes during their preparation and service periods,is merging as a momentous trending in materials ***,the traditional exploration approach for database development relies heavily on expertize and labor-intensive computation,and is thus intractable for complex *** this paper,we augmented the HitdIC(high-throughput determination of interdiffusion coefficients,https://***)software into a computation framework for automatic and efficient extraction of interdiffusion coefficients and development of atomic mobility database directly from large number of experimental composition *** an efficient framework proceeds in a workflow of automation concerning techniques of data-cleaning,feature engineering,regularization,uncertainty quantification and parallelism,for sake of agilely establishing high-quality kinetic database for target *** of the developed infrastructures was finally conducted in fcc CoCrFeMnNi high-entropy alloys with a dataset of 170 diffusion couples and 34,000 composition points for verifying their reliability and *** investigation over the obtained kinetic descriptions indicated that the sluggish diffusion is merely unilateral interpretation over specific composition and temperature ranges affiliated to limited *** is inferred that data-mining over large number of experimental data with the combinatorial infrastructures are superior to reveal extremely complex composition-and temperature-dependent thermal–physical properties.

关键词： alloys diffusion database