检索结果-南通市图书馆

Computational Visual Media 2024年第3期10卷 543-558页

作者： Qing Han Longfei Li Weidong Min Qi Wang Qingpeng Zeng Shimiao Cui Jiongjin Chen School of Mathematics and Computer Sciences Nanchang UniversityNanchang 330031China Institute of Metaverse Nanchang UniversityNanchang 330031China Jiangxi Key Laboratory of Smart City Nanchang 330031China

Existing unsupervised person re-identification approaches fail to fully capture thefine-grained features of local regions,which can result in people with similar appearances and different identities being assigned the same label after *** identity-independent information contained in different local regions leads to different levels of local *** address these challenges,joint training with local soft attention and dual cross-neighbor label smoothing(DCLS)is proposed in this ***,the joint training is divided into global and local parts,whereby a soft attention mechanism is proposed for the local branch to accurately capture the subtle differences in local regions,which improves the ability of the re-identification model in identifying a person’s local significant ***,DCLS is designed to progressively mitigate label noise in different local *** DCLS uses global and local similarity metrics to semantically align the global and local regions of the person and further determines the proximity association between local regions through the cross information of neighboring regions,thereby achieving label smoothing of the global and local regions throughout the training *** extensive experiments,the proposed method outperformed existing methods under unsupervised settings on several standard person re-identification datasets.

关键词： person re-identification(Re-ID) unsupervised learning(USL) local soft attention joint training dual cross-neighbor label smoothing(DCLS)

CFD investigation of structural effects of internal gas intake on powder conveying performance in fuel supply systems for aerospace engines

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第9期92卷 140-154页

作者： Guanlong Ren Haijun Sun Fangjun Chen Wen Shen Yunzhen Cai Yihua Xu Henrik Ström Bilainu Oboirien Qingang Xiong School of Aircraft Engineering Nanchang Hangkong UniversityNanchang330063China Engineering Research Center of Aero-engine Technology for General Aviation Ministry of EducationNanchang330063China State Key Laboratory of Pulp and Paper Engineering South China University of TechnologyGuangzhou510640China Department of Mechanics and Maritime Sciences Chalmers University of TechnologyGöteborg41296Sweden Department of Chemical Engineering University of JohannesburgJohannesburg17011South Africa

Optimal design of gas intake in powder fuel supply systems is crucial for performance of aerospace *** is little research on the impact of intake structure on powder conveying *** novel internal intakes were proposed,which are spherical,cube-shaped,and *** validation,CFD simulations demonstrate that fluctuation of mass flow rate of powders in the dome-shaped intake is reduced by about 73.3%compared with the annular external *** trends of phase velocities are similar for the spherical and cube-shaped intakes,while those are similar for the annular external and dome-shaped internal *** of area of gas zone for the annular external and spherical internal intakes is larger than that for the cube-shaped and dome-shaped internal *** and relative pressure drop in the fluidization chamber have a stable stage,and fluctuation of relative pressure drop is small when dome-shaped internal intake is used.

关键词： Powder supply system Intake structure Dense gas-solid flow Two-fluid model Powder fluidization Pressure drop

Alcohol drinking triggered decrease of oxidative balance score is associated with high all-cause and cardiovascular mortality in hypertensive individuals:findings from NHANES 1999–2014

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Geriatric Cardiology 2024年第8期21卷 779-790页

作者： Yu-Jun ZHANG Jing-Jing SONG Jian-Hao ZHAN Chu-Lin ZHOU Ao LI Mao-Qi WANG Ben-Jie LI Cong-Cong DING Yi-Wei ZHANG Zi-Heng TAN Zai-Hua CHENG Xiao HUANG Department of Cardiology the Second Affiliated HospitalJiangxi Medical CollegeNanchang UniversityNanchangChina Huankui Academy Nanchang UniversityNanchangChina School of Ophthalmology and Optometry of nanchang university NanchangChina The Second Clinical Medical College Nanchang UniversityNanchangChina Queen Mary School Nanchang UniversityNanchangChina The First Clinical Medical College Nanchang UniversityNanchangChina Department of Cardiovascular Medicine Huzhou First People’s HospitalZhejiangChina

BACKGROUND Oxidative stress is closely associated with hypertensive *** oxidative balance score(OBS)measures oxidative stress exposure from dietary and lifestyle *** objective of this study was to investigate the association between OBS and mortality in hypertensive *** This study included 7823 hypertensive patients from the National Health and Nutrition Examination Survey(NHA-NES)*** models,including Cox regression,restricted cubic splines(RCS),Kaplan-Meier survival analysis,subgroup,and sensitivity analyses,were exploited to investigate the relationship between OBS and the risk of *** Controlling for all potential confounders,a significantly inverse association was observed between elevated OBS and all-cause[hazard ratio(HR)=0.90,95%CI:0.85-0.95]and cardiovascular mortality(HR=0.85,95%CI:0.75-0.95).With adjustment for covariates,significant associations between lifestyle OBS and mortality risks diminished,whereas associations between dietary OBS and these mortality risks remained robust(all-cause mortality:HR=0.91,95%CI:0.86-0.96;cardiovascular mortality:HR=0.85,95%CI:0.76-0.96).RCS demonstrated a linear relationship between OBS and all-cause and cardiovascular mortality risk(P_(nonlinear)=0.088 and P_(nonlinear)=0.447,respectively).Kaplan-Meier curves demonstrated that the mortality rate was lower with a high OBS(P<0.001).The consistency of the association was demonstrated in subgroup and sensitivity *** after stratification showed that among current drinkers,those with higher OBS had a lower risk of mortality compared with former or never *** In hypertensive individuals,there was a negative association between OBS and all-cause and cardiovascular *** hypertensive individuals,especially those currently drinking,to maintain high levels of OBS may be beneficial in improving their prognosis.

关键词： high finding Alcohol

A Mixed-Variable Experimental Design Method

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2024年第2期14卷 343-352页

作者： Zili Wan Qi Wang College of Aircraft Engineering Nanchang Hangkong University Nanchang China

Mixed-variable problems are inevitable in engineering. However, few researches pay attention to discrete variables. This paper proposed a mixed-variable experimental design method (ODCD): first, the design variables were divided into discrete variables and continuous variables;then, the DVD method was employed for handling discrete variables, the LHD method was applied for continuous variables, and finally, a Columnwise-Pairwise Algorithm was used for the overall optimization of the design matrix. Experimental results demonstrated that the ODCD method outperforms in terms of the sample space coverage performance.

关键词： Optimization Experimental Design Methods Discrete Variable

Simultaneous guidance of electromagnetic and elastic waves via glide symmetry phoxonic crystal waveguides

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第3期33卷 363-368页

作者：雷林霖何灵娟廖清华刘文兴于天宝 School of Physics and Materials Science Nanchang UniversityNanchang 330031China

A phoxonic crystal waveguide with the glide symmetry is designed,in which both electromagnetic and elastic waves can propagate along the glide plane at the same *** to the glide symmetry,the bands of the phoxonic crystal super-cell degenerate in pairs at the boundary of the Brillouin *** is the so-called band-sticking effect and it causes the appearance of gapless *** adjusting the magnitude of the glide dislocation the edge bandgaps,the bandgap of the guided-modes at the boundary of the Brillouin zone,can be further *** photonic and phononic guided-modes can then possess only one mode for a certain frequency with relatively low group velocities,achieving single-mode guided-bands with relatively flat dispersion *** addition,there exists acousto-optic interaction in the cavity constructed by the glide *** proposed waveguide has potential applications in the design of novel optomechanical devices.

关键词： phoxonic crystals glide symmetry waveguide acousto-optic interaction

Exploration on the Optimization Strategy for the Layup of Composite Material Pressure Vessels Based on Advanced Algorithms

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2024年第9期14卷 2482-2505页

作者： Qingshan Zeng Zuxin Chen School of Aircraft Engineering Nanchang Hangkong University Nanchang China

This study aims to explore the influence of the laying angle on the pressure shell structure made of composite materials under the condition of a fixed shape. By using a composite material composed of a mixture of T800 carbon fiber and AG80 epoxy resin to design pressure vessels, this material combination can significantly improve the interlaminar shear strength and heat resistance. The article elaborates on the basic concepts and failure criteria of composite materials, such as the maximum stress criterion, the maximum strain criterion, the Tsai-Hill criterion, etc. With the help of the APDL parametric modeling language, the arc-shaped, parabolic, elliptical, and fitting curve-shaped pressure vessel models are accurately constructed, and the material property settings and mesh division are completed. Subsequently, APDL is used for static analysis, and the genetic algorithm toolbox built into Matlab is combined to carry out optimization calculations to determine the optimal laying angle. The research results show that the equivalent stress corresponding to the optimal laying angle of the arc-shaped pressure vessel is 5.3685e+08 Pa, the elliptical one is 5.1969e+08 Pa, the parabolic one is 5.8692e+08 Pa, and the fitting curve-shaped one is 5.36862e+08 Pa. Among them, the stress distribution of the fitting curve-shaped pressure vessel is relatively more uniform, with a deformation of 0.568E−03 m, a minimum equivalent stress value of 0.261E+09 Pa, a maximum equivalent stress value of 0.537E+09 Pa, and a ratio of 0.48, which conforms to the equivalent stress criterion. In addition, the fitting curve of this model can adapt to various models and has higher practical value. However, the stress distribution of the elliptical and parabolic pressure vessels is uneven, and their applicability is poor. In the future, further exploration can be conducted on the application of the fitting curve model in composite materials to optimize the design of pressure vessels. This study p

关键词： Composite Material Pressure Vessel Matlab APDL Parametric Modeling Static Analysis Optimal Laying Angle

Research on the Damping Mechanism of Time-Delay Coupled Negative Stiffness Dynamic Absorber in Nonlinear Vibration Damping System

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2024年第4期14卷 818-832页

作者： Weikai Wang Yanying Zhao Qiqi Li Hao Wu Liuqing Yang School of Aircraft Engineering Nanchang Hangkong University Nanchang China

A study was conducted on the effect of time delay and structural parameters on the vibration reduction of a time delayed coupled negative stiffness dynamic absorber in nonlinear vibration reduction systems. Taking dynamic absorbers with different structural and control parameters as examples, the effects of third-order nonlinear coefficients, time-delay control parameters, and negative stiffness coefficients on reducing the replication of the main system were discussed. The nonlinear dynamic absorber has a very good vibration reduction effect at the resonance point of the main system and a nearby area, and when 1 increases to a certain level, the stable region of the system continues to increase. The amplitude curve of the main system of a nonlinear dynamic absorber will generate Hop bifurcation and saddle node bifurcation in the region far from the resonance point, resulting in almost periodic motion and jumping phenomena in the system. For nonlinear dynamic absorbers with determined structural parameters, time-delay feedback control can be adopted to control the amplitude of the main system. For different negative stiffness coefficients, there exists a minimum damping point for the amplitude of the main system under the determined system structural parameters and time-delay feedback control parameters.

关键词： Time Delay Nonlinear Dynamic Vibration Absorber

Optimization performance of quantum endoreversible Otto machines with dual-squeezed reservoirs

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第10期33卷 198-204页

作者： Haoguang Liu College of Science and Technology Nanchang Aeronautical UniversityNanchang 332020China

We consider a quantum endoreversible Otto engine cycle and its inverse operation-Otto refrigeration cycle,employing two-level systems as the working substance and operating in dual-squeezed *** demonstrate that the efficiency of heat engines at maximum work output and the coefficient of performance for refrigerators at the maximum c criterion will degenerate toη-=η_(C)/(2-η_(C))andε-=(√9+8ε_(C)-3)/2 when symmetric squeezing is satisfied,*** also investigated the influences of squeezing degree on the performance optimization of quantum Otto heat engines at the maximum work output and refrigerators at the maximum X *** analytical results show that the efficiency of heat engines at maximum work output and the coefficient of performance for refrigerators at the maximum X criterion can be improved,reduced or even inhibited in asymmetric ***,we also find that the efficiency of quantum Otto heat engines at maximum work output is lower than that obtained from the Otto heat engines based on a single harmonic oscillator ***,the coefficient of performance of the corresponding refrigerator is higher.

关键词： quantum Otto heat engine quantum Otto refrigerator optimization performance dual-squeezed reservoirs

Analysis and Research on Aerodynamic Characteristics of Quad Tilt Rotor Aircraft

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Advances in Aerospace Science and Technology 2024年第1期9卷 28-39页

作者： Jike Jia Xiaomei Ye Guoyi He Qingjin Huang Zhile Hong Faculty of Flight Engineering Nanchang Hangkong University Nanchang China

For the quad tilt rotor aircraft, a computational fluid dynamics method based on multiple reference frames (MRF) was used to analyze the influence of aerodynamic layout parameters on the aerodynamic characteristics of the quad tilt rotor aircraft. Firstly, a numerical simulation method for the interference flow field of the quad tilt rotor aircraft is established. Based on this method, the aerodynamic characteristics of isolated rotors, rotor combinations at different lateral positions on the wing, and rotor rotation directions under different inflow velocities were calculated and analyzed, in order to grasp their aerodynamic interference laws and provide reference for the design and control theory research of such aircraft.

关键词： Quad Tilt Rotor Aircraft Analysis of Aerodynamic Characteristics CFD Method

The Key Path of the Shape Optimization Design of Isotropic Material Pressure Vessels

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Engineering and Technology 2024年第3期12卷 775-797页

作者： Qingshan Zeng Zuxin Chen School of Aircraft Engineering Nanchang Hangkong University Nanchang China

An optimization design was conducted for the shape of the pressure vessel with a thin-shell shell. During this process, the optimization calculation was performed with the aid of the genetic algorithm toolbox included in Matlab. Firstly, through the parametric modeling function of APDL, models such as arc-shaped, parabolic, elliptical, and those generated by the fitting curve command were successfully constructed. Meanwhile, the relevant settings of material properties were accomplished, and the static analysis was conducted. Secondly, the optimization calculation process was initiated using the genetic algorithm toolbox in Matlab. Eventually, through analysis and judgment, the model generated by the fitting curve command was relatively superior within the category of the best shape.

关键词： Optimization Design Parametric Modeling Thin-Shell Shell Matlab Genetic Algorithm Toolbox