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A REVISED SOLUTION OF EQUIVALENT PERMEABILITY TENSOR FOR DISCONTINUOUS FRACTURES

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Journal of Hydrodynamics 2012年第5期24卷 711-717页

作者： HE Ji chen Sheng-hong SHAHROUR Isam State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University 430072Wuhan China Laboratoire Genie Civil et geo-Environnement University Lille 1 59650 Villeneuve d Ascq France

The equivalent permeability tensor is essential to the application of the equivalent porous media model in the numerical seepage simulation for fractured rock masses. In this paper, a revised solution of the equivalent permeability tensor is proposed to represent the influence of the fracture connectivity in discontinuous fractures. A correction coefficient is involved to reflect the com- plex seepage flow type through the rock bridge. This correction coefficient is back analyzed from single-hole packer tests, based on the Artificial Neural Network （ANN） back analysis and the Finite Element Method （FEM） seepage simulation. The limitation of this back analysis algorithm is that the number of single-hole packer tests should be equal or greater than the number of fracture sets, and three is the maximum number of the fracture sets. The proposed solution and the back analysis algorithm are applied in the permea- bility measurement and the seepage simulation for the Xiaowan arch dam foundation.

关键词： discontinuous fractures permeability tensor back analysis packer test Artificial Neural Network (ANN)

Scaling Behaviors of Polymers on Lipid Membranes:Coupling of Polymer Chain Dynamics and Surface Thermal Fluctuations

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Chinese Journal of Polymer Science 2023年第3期41卷 459-464,I0010页

作者： Zi-Ren chen Wu Zhou Lei Shen School of Chemistry Chemical Engineering and Life ScienceWuhan University of TechnologyWuhan 430070China

Despite extensive researches on the motion of polymer chains on lipid membranes,the effect of membrane fluctuations on polymer chain dynamics remains poorly *** we report single molecule tracking experiments that allow for comparable measurements of polymer chain diffusion dynamics on nanotubular and planar phospholipid *** observe a super-diffusion behavior and no apparent chain-length-dependent mobility of polymer chains on nanotubular membranes,while a Brownian motion and apparent chain-lengthdependent mobility of polymer chains on planar *** suggest the super-diffusion nature of polymer chains may be due to the thermal-fluctuations of lipid nanotubes,which can be described from a statistical thermodynamic phenomenon coupling of polymer chain dynamics and surface thermal *** suggest that the existence of surface environment fluctuations should influence the dynamics of the adsorbed polymer *** study provides previously uncharacterized insights into polymer diffusion dynamics on thermal-fluctuating flexible surfaces,which is essential to understanding the effect of environment fluctuations on polymer chain behaviors.

关键词： Polymer diffusion Lipid membrane Scaling behavior

A study on the surface overpressure distribution and formation of a double curvature liner under a two-point initiation

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Defence Technology（防务技术） 2022年第1期18卷 148-157页

作者： Jie Liu Xi chen Zhong-hua Du Nanging Vocational University of Industry Technology Nanjing210023China Nanjing University of Science and Technology Nanjing.210094China

The formation mechanism of an EFP(explosively formed projectile)using a double curvature liner under the overpressure effect generated by a regular oblique reflection was investigated in this *** on the detonation wave propagation theory,the change of the incident angle of the detonation wave collision at different positions and the distribution area of the overpressure on the surface of the liner were *** dimensional numerical simulations of the formation process of the EFP with *** well as the ability to penetrate 45#steel were performed using LS-DYNA software,and the EFP ve locity,the penetration ability,and the forming were assessed via experiments and x_ray *** experimental results coincides with those of the *** indicate that the collision of the detonation wave was controlled to be a regular oblique reflection acting on the liner by setting the di-mensions of the unit charge and maintai ning the pressure at the collision point region at more than 2.4 times the CJ detonation when the incident angle approached the cnitical *** distance from the liner midline to the boundary of the area within which the pressure ratio of the regular oblique reflection pressure to the qJ detonation pressure was greater than 2.5,2,and 15was approximately 0.66 mm,132 mm,and 3.3 mm,*** noted that pressure gradient caused the liner to turn inside out in the middle to form the head of the EFP and close the two tails of the EFP at approximately 120μ*** penetration depth of the EFP into a 45#steel target exceeded 30 mm,and there was radial expansion between the head and tail of the EFP,increasing the penetration resistance of the ***,the structural size of the unit charge and the liner can be further optimized to reduce resist ance to increase the penetration ability of the EFP.

关键词： Unit-shaped charge Double curvature liner Regular oblique reflection Two-point initiation Pene tra tion Numerical simulation

Construction of electron rich Fe active sites by FeCu alloy anchoring on carbon nitride for photocatalytic nitrogen reduction

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Rare Metals 2024年第4期43卷 1570-1579页

作者： Gang Dong Cong Huang Fei-Yang chen Xue-Qin Liu Zhen Li Xiao-Li Su Tao Zeng Yun-Xia chen Yi-Huang chen Yang Wang School of Materials Science and Engineering Jingdezhen Ceramic UniversityJingdezhen333403China Faculty of Materials Science and Chemistry China University of GeosciencesWuhan430074China College of Chemistry and Materials Engineering Wenzhou UniversityWenzhou325035China

Given the clean and inexhaustible solar energy from solar light,photocatalytic ammonia synthesis is extremely ***,high electron-hole recombination rates and insufficient active sites severely limited N2 photoreaction ***,we designed and fabricated FeCu alloy nanoparticles anchored on carbon nitride nanosheets with excellent photocatalyt ic ammonia synthesis *** a coupler between Fe and carbon nitride,Cu promotes the separation of photogenerated charge carriers in carbon nitride under solar light irradiation,and renters the semiconductor a forceful electron donor for the Fe active *** accumulated electrons at Fe sites furtherly facilitated the adsorption and activation of the molecular ***,the uniform dispersed FeCu alloy nanoparticles were on carbon nitride nanosheets enhanced the stability of photocataly tic nitrogen reduction reaction,making the artificial photocataly tic ammonia synthesis more sustainable for *** work highlights that a direct electron transfer channel can be used to regulate the photochemical nitrogen fixation network.

关键词： Photocatalytic N_2 fixation Carbon nitride FeCu alloy Active sites Hydrogenation pathway

Design and test of soft-pot-tray automatic embedding system for light-economical pot seedling nursery machine

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International Journal of Agricultural and Biological Engineering 2020年第1期13卷 91-100页

作者： Lintao chen Xu Ma Cong Wang Hongwei Li Zehua Li Xueshen chen Tao chen College of Engineering South China Agricultural UniversityGuangzhou 510642China College of Mathematics and Informatics South China Agricultural UniversityGuangzhou 510642China

Most of the commercially-available pot seedling nursery machines are incompatible with soft-pot-trays and are labor-intensive and low in productivity.A soft-pot-tray automatic embedding system was developed in this study to achieve automatic embedding of the soft pot tray into the hard tray following sowing and covering with soil.A control system was constructed using the Arduino program development *** embedded-hard-tray automatic lowering mechanism and conveyor-belt-based pot-tray embedding system were *** analysis was conducted to derive an equation to describe the embedding process of the soft pot tray into the embedded hard tray.A prototype of the soft-pot-tray automatic embedding system was manufactured and *** analytical equation suggested that a minimum linear velocity of 0.86 m/s was required for a complete embedding *** experimental results showed that the embedded-hard-tray automatic lowering mechanism was reliable and stable as the tray placement success rate was greater than 99%.The successful tray embedding rate was 100%and the seed exposure rate was less than 1%with a linear velocity of the conveyor belt of 0.92 m/*** experiment findings agreed well with the analytical *** proposed soft-pot-tray automatic embedding system satisfied the technical specifications for a light-economical pot seedling nursery machine.

关键词： automatic embedding pot seedling nursery machine embedded hard tray soft pot tray conveyor-belt embedding system

Fractal derivative multi-scale model of fluid particle transverse accelerations in fully developed turbulence

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Science China(Technological Sciences) 2009年第3期52卷 680-683页

作者： HongGuang Sun Wen chen Department of Engineering Mechanics Hohai University Nanjing 210098 China

The Tsallis distribution and the stretched exponential distribution were successfully used to fit the experimental data of turbulence particle acceleration published in Nature (2001), which manifested a clear departure from the normal distribution. These studies, however, fall short of a clear physical mechanism behind the statistical phenomenological description. In this study, we propose a multi- scale diffusion model which considers both normal diffusion in molecular-scale and anomalous diffu- sion in vortex-scale, and the latter is described by a novel fractal derivative modeling approach. This multi-scale model gives rise to a new probability density function which fits experimental data very well.

关键词： fully developed homogeneous turbulence probability density function (PDF) anomalous diffusion power-stretched Gaussian distribution (PSGD) fractal derivative

Separation of small molecular peptides with the same amino acid composition but different sequences by high performance liquid chromatography-electrospray ionization-mass spectrometry

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Science China Chemistry 2009年第12期52卷 2264-2268页

作者： LIU LiHong chen ZiLin Department of Pharmaceutical Analysis College of PharmacyWuhan UniversityWuhan 430072China

Peptidomics has emerged as a new discipline in recent years. Mass spectrometry (MS) is the most universal and efficient tool for structure identification of proteins and peptides. However,there is a limitation for the identification of peptides with the same amino acid composition but different se-quences because these peptides have identical mass spectra of molecular ions. This paper presents a high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) method for the separation of small molecular peptides with the same amino acid composition but dif-ferent sequences. Two tripeptides of Gly-Ser-Phe and Gly-Phe-Ser were used as a model sample. The separation behavior has been investigated and the separation conditions have been optimized. Under the optimum conditions,good repeatability was achieved. The developed method could provide a helpful reference for the separation of other peptides with the same amino acid composition but different sequences in the study of proteomics and peptidomics.

关键词： reversed-phase chromatography mass spectrometry peptides amino acid

Performance of wavecatcher intakes at angles of attack and sideslip

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Chinese Journal of Aeronautics 2021年第7期34卷 244-256页

作者： Fengyuan ZUO Sannu MO LDER Gang chen State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an 710049China Ryerson University Toronto ON M5B 2K3Canada

A wavecatcher type scramjet intake,that reduces the Mach number number from 4 to 1.552,is used as the basis for a study of flow starting/unstarting as affected by freestream angles of attack and *** intake design is based on a morphed streamtube consisting of two conical flow streamlines using streamline tracing and osculating axisymmetric design *** flow and performance is modeled using the numerical CFD code and the k-e turbulence *** intake unstarts at a sideslip angle of 2,a positive angle of attack of 1.Both positive angle of attack and sideslip angle have an adverse effect on the startability of the MBus *** negative angles,the intake initially unstarts at5angle of attack,due to the thickened shear layer induced by the streamwise *** it re-starts at8angle of attack,mainly due to the expansion fan formed at the leading edge,causing the shock wave structures inside the intake to be reestablished.

关键词： Angle of attack Sideslip angle Unstart Wavecatcher intake

Feature selection of BOF steelmaking process data by using an improved grey wolf optimizer

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Journal of Iron and Steel Research International 2022年第8期29卷 1205-1223页

作者： Zong-xin chen Hui Liu Long Qi Faculty of Information Engineering and Automation Kunming University of Science and TechnologyKunming 650500YunnanChina Yunnan Key Laboratory of Artificial Intelligence Kunming University of Science and TechnologyKunming 650500YunnanChina

Basic oxygen furnace(BOF)steelmaking end-point control using soft measurement models has essential value for economy and ***,the high-dimensional and redundant data of the BOF collected by the sensors will hinder the performance of *** traditional feature selection results based on meta-heuristic algorithms cannot meet the stability of actual industrial *** order to eliminate the negative impact of feature selection application in the BOF steelmaking,an improved grey wolf optimizer(IGWO)for feature selection was proposed,and it was applied to the BOF data ***,the proposed algorithm preset the size of the feature subset based on the new encoding scheme,rather than the traditional uncertain number ***,opposition-based learning was used to initialize the grey wolf population so that the initial population was closer to the potential optimal *** addition,a novel population update method retained the features closely related to the best three grey wolves and probabilistically updated irrelevant features through measurement or random *** methods were used to search feature subsets to maximize search capability and stability of algorithm on BOF steelmaking ***,the proposed algorithm was compared with other feature selection algorithms on the BOF data *** results show that the proposed IGWO can stably select the feature subsets that are conductive to the end-point regression accuracy control of BOF temperature and carbon content,which can improve the performance of the BOF steelmaking.

关键词： Basic oxygen furnace Feature selection Grey wolf optimization Regression Opposition-based learning