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A debris-flow impact pressure model combining material characteristics and flow dynamic parameters

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Journal of Mountain Science 2018年第12期15卷 2721-2729页

作者： TANG jin-bo HU Kai-heng Key Laboratory of Mountain Hazards and Surface Process Chinese Academy of SciencesChengdu 610041China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China

Impact force is a crucial factor to be considered in debris-resisting structure design. The impact of debris flow against a structural barrier depends not only on the flow dynamics but also on the barrier material. Based on the structural vibration equation and energy conservation law, a simple model for calculating debris-flow impact pressure is proposed, which includes the mechanical impedance of the material, debris-flow velocity and Froude number. Twenty-five impact tests have been conducted using different kinds of materials: steel, black granite, white granite, marble and polyvinyl chloride(PVC) board, and the ratio of the maximum impact time to the vibration period of the structure is determined for the model. It is found that the ratio's square root shows a linear relationship with the material solid Froude number. This indicates that the impedance of the structures plays an important role in the flow-barrier interaction. Moreover, the debrisflow impact force is found to decrease with the travel time of the elastic stress wave though the structures.

关键词： Debris flows Impact pressure Dynamical responses Mechanical impedance

Dark and multi-dark solitons in the three-component nonlinear Schrodinger equations on the general nonzero background

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Chinese Physics B 2019年第12期28卷 60-67页

作者： Zhi-jin xiong Qing Xu Liming Ling School of Electric Power Engineering South China University of TechnologyGuangzhou 510640China School of Mathematics South China University of TechnologyGuangzhou 510640China

We exhibit some new dark soliton phenomena on the general nonzero background for a defocusing three-component nonlinear Schrodinger equation. As the plane wave background undergoes unitary transformation SU(3), we obtain the general nonzero background and study its modulational instability by the linear stability analysis. On the basis of this background, we study the dynamics of one-dark soliton and two-dark-soliton phenomena, which are different from the dark solitons studied before. Furthermore, we use the numerical method for checking the stability of the one-dark-soliton solution. These results further enrich the content in nonlinear Schrodinger systems, and require more in-depth studies in the future.

关键词： dark soliton three-component nonlinear Schrodinger equations general nonzero background

DiLFM:an artifact-suppressed and noise-robust light-field microscopy through dictionary learning

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Light(Science & Applications) 2021年第8期10卷 1546-1557页

作者： Yuanlong Zhang bo xiong Yi Zhang Zhi Lu Jiamin Wu Qionghai Dai Department of Automation Tsinghua UniversityBeijing 100084China. lnstitute for Brain and Cognitive Sciences Tsinghua UniversityBeijing 100084China. Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China

Light field microscopy(LFM)has been widely used for recording 3D biological dynamics at camera frame ***,LFM suffers from artifact contaminations due to the illness of the reconstruction problem via naive Richardson-Lucy(RL)***,the performance of LFM significantly dropped in low-light conditions due to the absence of sample *** this paper,we thoroughly analyze different kinds of artifacts and present a new LFM technique termed dictionary LFM(DiLFM)that substantially suppresses various kinds of reconstruction artifacts and improves the noise robustness with an over-complete *** demonstrate artifact-suppressed reconstructions in scattering samples such as Drosophila embryos and ***,we show our DiLFM can achieve robust blood cell counting in noisy conditions by imaging blood cell dynamic at 100 Hz and unveil more neurons in whole-brain calcium recording of zebrafish with low illumination power in vivo.

关键词： scattering noise recording

Subreflector model depending on elevation for the Tianma 65 m Radio Telescope

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Research in Astronomy and Astrophysics 2016年第8期16卷 9-16页

作者： Zheng-xiong Sun jin-Qing Wang Lan Chen Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China Shanghai Institute of Technology Shanghai 201400 China

A subreflector adjustment system for the Tianma 65 m radio telescope, administered by Shanghai Astronomical Observatory, has been installed to compensate for gravitational deformation of the main re- flector and the structure supporting the subreflector. The position and attitude of the subreflector are variable in order to improve the efficiency at different elevations. The subreflector model has the goal of improving the antenna＇s performance. A new fitting formulation which is different from the traditional formulation is proposed to reduce the fitting error in the Y direction. The only difference in the subreflector models of the 65 m radio telescope is the bias of a constant term in the Z direction. We have investigated the effect of movements of the subreflector on the pointing of the antenna. The results of these performance measure- ments made by moving the antenna in elevation show that the subreflector model can effectively improve the efficiency of the 65 m radio telescope at each elevation. An antenna efficiency of about 60% at the Ku band is reached in the whole angular range of elevation.

关键词： telescopes -- methods: observational -- methods: data analysis

Effect of Joule heating on the electroosmotic microvortex and dielectrophoretic particle separation controlled by local electric field

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Chinese Physics B 2021年第11期30卷 401-410页

作者： Bing Yan bo Chen Yongliang xiong Zerui Peng School of Aerospace Engineering Huazhong University of Science and TechnologyWuhan 430074China

Dielectrophoresis(DEP)technology has become important application of microfluidic technology to manipulate *** using a local modulating electric field to control the combination of electroosmotic microvortices and DEP,our group proposed a device using a direct current(DC)electric field to achieve continuous particle *** this paper,the influence of the Joule heating effect on the continuous separation of particles is *** show that the Joule heating effect is caused by the local electric field,and the Joule heating effect caused by adjusting the modulating voltage is more significant than that by driving ***,a non-uniform temperature distribution exists in the channel due to the Joule heating effect,and the temperature is the highest at the midpoint of the modulating *** channel flux can be enhanced,and the enhancement of both the channel flux and temperature is more obvious for a stronger Joule heating *** addition,the ability of the vortices to trap particles is enhanced since a larger DEP force is exerted on the particles with the Joule heating effect;and the ability of the vortex to capture particles is stronger with a stronger Joule heating *** separation efficiency can also be increased because perfect separation is achieved at a higher channel *** optimization of the separation device,such as the convective heat transfer coefficient of the channel wall,the length of modulating electrode,and the width of the channel,is performed.

关键词： dielectrophoresis microvortices Joule heating effect particle separation

An Approximation Algorithm for P-prize-collecting Set Cover Problem

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Journal of the Operations Research Society of China 2023年第1期11卷 207-217页

作者： jin-Shuang Guo Wen Liu bo Hou School of Mathematical Sciences Hebei Key Laboratory of Computational Mathematics and ApplicationsHebei Normal UniversityShijiazhuang050024HebeiChina

In this paper,we consider the P-prize-collecting set cover(P-PCSC)problem,which is a generalization of the set cover *** this problem,we are given a set system(U,S),where U is a ground set and S⊆2U is a collection of subsets satisfying∪S∈SS=*** subset in S has a nonnegative cost,and every element in U has a nonnegative penalty cost and a nonnegative *** goal is to find a subcollection C⊆S such that the total cost,consisting of the cost of subsets in C and the penalty cost of the elements not covered by C,is minimized and at the same time the combined profit of the elements covered by C is at least P,a specified profit *** main work is to obtain a 2f+ε-approximation algorithm for the P-PCSC problem by using the primal-dual and Lagrangian relaxation methods,where f is the maximum frequency of an element in the given set system(U,S)andεis a fixed positive number.

关键词： P-prize-collecting set cover problem Approximation algorithm Primal-dual Lagrangian relaxation

Photo-assisted Cl doping of SnO_(2) electron transport layer for hysteresis-less perovskite solar cells with enhanced efficiency

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Rare Metals 2022年第2期41卷 361-367页

作者： jin-bo Wu Chao Zhen Gang Liu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

Developing efficient electron transport layers(ETLs)along with proper interface engineering is crucial to achieve high-performance perovskite solar cells(PSCs).Herein,a photo-assisted doping strategy was developed to modify SnO_(2)ETLs with Cl^(-)for efficient *** Cl^(-)modified SnO2(Cl^(-)SnO_(2))with passivated surface defects as ETL material favors the formation of high phase-purity perovskite films and promotes the electron collection across the SnO_(2)/perovskite ***,the efficiency of PSC is improved from 16.35%without Cl modification to 18.94%with the Cl modification,with little hysteresis and high stability.

关键词： stability perovskite transport

Seasonally evolving dominant interannual variability mode of air-sea CO2 flux over the western North Pacific simulated by CESM1-BGC

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Science China Earth Sciences 2017年第10期60卷 1854-1865页

作者： jin ChenXi ZHOU TianJun CHEN XiaoLong WU bo LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Beijing Meteorological Service Center Beijing 100089 China University of Chinese Academy of Sciences Beijing 100049 China

We applied a season-reliant empirical orthogonal function(S-EOF) analysis based on the results of the Community Earth System Model, version 1-Biogeochemistry, to seasonal mean air-sea CO_2 flux over the western North Pacific(WNP)(0°–35°N, 110°E–150°E). The first leading mode accounts for 29% of the total interannual variance, corresponding to the evolution of the El Ni-Southern Oscillation(ENSO) from its developing to decaying phases. During the ENSO developing phase in the summer and fall, the contribution of surface seawater CO_2 partial pressure anomalies is greater than that of gas transfer/solubility anomalies, which contribute to increasing oceanic CO_2 uptake over the WNP. During the ENSO mature phase in the winter, the anomalous southwesterly northwest of the western North Pacific anticyclone(WNPAC) reduces the surface wind speed in the China marginal sea and thus decreases oceanic CO_2 uptake by reducing the gas transfer coefficient. In the subsequent spring, the WNPAC maintains with an eastward shift in position. The anomalous southwesterly warms sea surface temperatures in the China marginal sea by reducing evaporation and thus decreases oceanic CO_2 uptake by enhancing surface seawater CO_2 partial pressure. This process, rather than the effect of decreasing gas transfer coefficient, dominates CO_2 flux anomalies in the spring.

关键词： Air-sea CO2 flux Western North Pacific Interannual variability ENSO

An Intelligent Scheduling Approach for Electric Power Generation

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Chinese Journal of Electronics 2018年第6期27卷 1170-1175页

作者： YU Li jin Xin LI Zeng xiong Yan HUANG Wenchao College of Computer Science and Engineering Anhui University of Science and Technology School of Computer Science and Technology University of Science and Technology of China

Although China is vigorously developing clean energy and nuclear power, the thermal power generation(mainly coal power) is still the most important power generation method at present. Economic load dispatch(ELD) is a typical optimization problem in power systems which lots of researchers are trying to *** purpose of ELD is to increase the efficiency of thermal power generation under the conditions of load and operational constraints. When it comes to power generation scheduling, manual operation is still the main form,which is inefficient. In order to use a large amount of historical power generation data to improve the efficiency of power generation scheduling and achieve the effect of energy conservation, we propose an intelligent power generation scheduling system based on Deep neural networks(DNN) and Ant colony optimization(ACO). Experiments show that our DNN algorithm can predict the unit coal consumption precisely. Compared with the dynamic programming algorithm and equal differential increment rate algorithm, ACO can complete power generation scheduling tasks more quickly and efficiently.

关键词： Deep learning Ant colony optimization(ACO) Smart grid