检索结果-南通市图书馆

Complex System Modeling and Simulation 2023年第3期3卷 220-235页

作者： Linfeng Liu Hao Ye Wei Dong Junfeng Cui Department of Automation Tsinghua UniversityBeijing 100084China Beijing National research center for Information Science and Technology Tsinghua UniversityBeijing 100084China CRSC research&design Institute Group Co. LtdBeijing 100070China

With the advantages of levitation/guidance self-stability,large levitation gap,and high lift-to-drag ratios,superconducting electrodynamic suspension(SC-EDS)train is becoming a viable candidate for the high-speed and ultra-high-speed rail transportation.In order to provide the basis for designing the optimization and control strategy,this paper establishes a comprehensive model for the SC-EDS train,which considers the dynamics of the bogie and car body in all directions.The obtained model reveals the complex coupling and feedback relationships among the variables,which cannot be described by the existing local models of the SC-EDS train.Simulation examples under different parameters and initial conditions are presented and discussed to demonstrate the potential use of the model given in this paper.

关键词： superconducting electrodynamic suspension train comprehensive model coupling and feedback analysis numerical simulation

research on anti-attack performance of a private cloud safety computer based on the Markov-Percopy dynamic heterogeneous redundancy structure

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Transportation Safety and Environment 2023年第4期5卷 107-116页

作者： Jiakun Wen Zhen Liu Huan Ding CRSC research&design Institute Group Co.Ltd Beijing 100070China

With the increasing computing demand of train operation control systems,the application of cloud computing technology on safety computer platforms of train control system has become a research hotspot in recent years.How to improve the safety and availability of private cloud safety computers is the key problem when applying cloud computing to train operation control systems.Because the cloud computing platform is in an open network environment,it can face many security loopholes and malicious network at-tacks.Therefore,it is necessary to change the existing safety computer platform structure to improve the attack resistance of the private cloud safety computer platform,thereby enhancing its safety and reliability.Firstly,a private cloud safety computer platform architecture based on dynamic heterogeneous redundant(DHR)structure is proposed,and a dynamic migration mechanism for heterogeneous executives is designed.Then,a generalized stochastic Petri net(GSPN)model of a private cloud safety computer platform based on DHR is established,and its steady-state probability is solved by using its isomorphism with the continuous-time Markov model(CTMC)to analyse the impact of different system structures and executive migration mechanisms on the system's anti-attack performance.Finally,through experimental verifcation,the system structure proposed in this paper can improve the anti-attack capability of the private cloud safety computer platform,thereby improving its safety and reliability.

关键词： Safety computer logical monitoring method continuous time Markov modelling,cloud computing anti-attack analysis

Milling degree affects the fermentation properties of rice:perspectives from the composition of nutrients and gut microbiota via in vitro fermentation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2024年第3期13卷 1578-1588页

作者： Yu Zhang Fan Li Shutong Pan Bing Bai Kai Huang Sen Li Hongwei Cao Tian Xie Jian Xie Xiao Guan School of Health Science and Engineering University of Shanghai for Science and TechnologyShanghai 200093China National Grain Industry(Urban Grain and Oil Security)Technology Innovation center Shanghai 200093China Nutrition&Health research Institute Co.Ltd. COFCO CorporationBeijing 102209China China Grain Wuhan Scientific research&design Institute Co.Ltd. Wuhan 430079China

Fermentation substrates of rice with different milling degrees(MDs) were prepared and fermented with human feces to compare their fermentation properties and effects on gut microbiota.MD 0s,MD 5s and MD 60s represented brown rice,moderately-milled rice and white rice,respectively.After in vitro fermentation,the MD 5s group showed higher starch utilization,compared with the MD 0s and 60s groups evaluated by Fourier transform infrared spectrometer,and confocal laser scanning microscope.Effects of fermentation substrates of rice with different MDs on gut microbiota were evaluated by 16S rDNA sequencing.All the sample groups reduced the pH and produced short-chain fatty acids(SCFAs) and branched-chain fatty acids.The MD 5s group exhibited higher α-diversity than the MD 0s and 60s groups.Abundances of Phascolarctobacterium,Blautia and norank_f_Ruminococcaceae were higher in the MD 0s and 5s groups,compared with the MD 60s group.These bacteria were also positively correlated with the SCFAs production via Spearman correlation analysis.In vitro culture assay revealed that fermentation substrates of MD 0s and 5s promoted the growth of two probiotics(Akkermansia muciniphila and Bifidobacterium adolescentis).Our results showed that moderate milling might be an appropriate way to produce rice products with richer nutrients and better fermentation properties.

关键词： Rice processing Milling Whole grains Gut microbiota

Effects of Microstructure on Quasi⁃Static Transverse Loading Behavior of 3D Circular Braided Composite Tubes

在线全文

学校读者我要写书评

暂无评论

Journal of Donghua University(English Edition) 2021年第5期38卷 392-397页

作者：周海丽李超韩晨晨刘志艳周峰张立泉 Nanjing Fiberglass research&design Institute Nanjing 210000China

The effects of microstructure on quasi-static transverse loading behavior of 3D circular braided composite tubes were studied. Transverse loading tests were conducted. Transverse load-deflection curves were obtained to analyze the effects of braiding parameters including the braiding angle, the wall thickness, and the diameter on the transverse loading of 3D circular braided composite tubes. Breaking loads, moduli and strengths had also been used to describe the transverse loading behaviors. The failure morphologies were shown to reveal damage mechanisms. From the results, the increase in braiding angle, wall thickness and diameter increases the ability of anti-deformation and breaking load of braided tubes. The breaking load of specimen with a braiding angle of 45° is about 1.68 times that of specimen with a braiding angle of 15°. The breaking load of specimen with 4 layers of yarns is about 2.15 times that of specimen with 2 layers of yarns. The breaking load of the tube with a diameter of 25.5 mm is about 2.39 times that of the tube with a diameter of 20.5 mm.

关键词： 3D circular braided composite tube quasi⁃static transverse loading test braiding parameter failure morphology

research on the logic monitoring method for the cloud computing based safety computer

在线全文

学校读者我要写书评

暂无评论

Transportation Safety and Environment 2023年第2期5卷 79-87页

作者： Yaran Yang Lianchuan Ma Tao Tang Huan Ding Zhen Liu School of Electronic and Information Engineering Beijing Jiaotong UniversityBeijing 100044China National Engineering research center of Rail Transportation Operation and Control System Beijing Jiaotong UniversityBeijing 100044China State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong UniversityBeijing 100044China CRSC research&design Institute Group Co.Ltd. Beijing 100070China

With the development of railway construction in China,the computing demand of the train control system is increasing day by day.The application of cloud computing technology on the rail transit signal system has become a research hotspot in recent years.How to improve the safety and availability of the safety computer platform in the cloud computing environment is the key problem when applying cloud computing to the train operation control system.Since the cloud platform is in an open network environment,fac-ing many security vulnerabilities and malicious network attacks,it is necessary to monitor the operation of computer programmes through edge safety nodes.Firstly,this paper encrypts the logical monitoring method,and then proposes a secure computer de fence model based on the dynamic heterogeneous redundancy structure.Then the continuous time Markov chain(CTMC)is used to quantitatively solve the stable probability of the system,and the influence of different logical monitoring methods on the anti-attack performance of the system is analysed.Finally,the experiment proves that the dynamic heterogeneous redundancy structure composed of encryption logic monitoring can guarantee the safe and stable operation of the safety computer more effectively.

关键词： safety computer logical monitoring method continuous time Markov modelling(CTMC) cloud computing anti-aggression analysis

Changes of structure and functional properties of rice protein in the fresh edible rice during the seed development

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2023年第5期12卷 1850-1860页

作者： Dan Li Mingjing Yao Yang Yang Bing Wang Dongjie Zhang Na Zhang College of Food Science Heilongjiang Bayi Agriculture UniversityDaqing 163319China Engineering research center of Processing and Utilization of Grain By-products Ministry of EducationDaqing 163319China Key Laboratory of Food Science and Engineering of Heilongjiang Province Harbin University of CommerceHarbin 150076China Shandong Provincial Key Laboratory of Food and Fermentation Engineering Shandong Food Ferment Industry Research&Design InstituteQilu University of Technology(Shandong Academy of Sciences)Jinan 250013China

It has been reported that fresh edible rice has more bioactive compounds and its protein is easier to digest and has lower hypoallergenic than mature rice. In this paper, the changes in structure and functional properties of proteins at five different stages, including early milky stage(EMS), middle milky stage(MMS), late milky stage(LMS), waxy ripe stage(WS)and ripening stage(RS), during the seed development were investigated. It was found that with the seed developing, the molecular weight of fresh rice protein gradually become larger while the secondary structure changed from the highest content of disordered structure at MMS to the highest content of ordered structure at RS, which affect the surface hydrophobicity and then the functional properties of proteins, including foaming properties, emulsifying properties and oil holding capacity. Fresh rice protein at MMS has the strongest surface hydrophobicity while fresh edible rice protein at RS has the strongest oil holding capability. The results of our study can provide a theoretical basis for the application of fresh rice protein in the food industry and help to develop new fresh edible rice food.

关键词： Fresh edible rice Rice protein Protein structure Functional properties

Hair growth-promotion effects and antioxidant activity of the banana flower extract HappyAngel^(■):double-blind, placebo-controlled trial

在线全文

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2023年第5期12卷 1917-1923页

作者： Chia-Hua Liang Yung-Hsiang Lin Yung-Kai Lin Chi-Fu Chiang Department of Cosmetic Science and Institute of Cosmetic Science Chia Nan University of Pharmacy and ScienceTainan 71710China Research&Design Center TCI CO.Ltd.Taipei 114722China Institute of Food Safety and Risk Management Department of Food ScienceTaiwan Ocean UniversityKeelung 202301China Graduate Institute of Biomedical Engineering Chung Hsing UniversityTaichung 202301China

Banana flowers contain various bioactive components, including several antioxidants with anti-inflammatory effects. However, it is unclear whether they can reduce and prevent hair loss. This study examines the effect of banana flower extracts on preventing hair loss and strengthening hair roots. The banana flower extract(HappyAngel^(■))was used to treat human hair follicle dermal papilla cells(HFDPCs)and the expression of reactive oxygen species(ROS), dihydrotestosterone(DHT), and hair-related genes(SRD5A1, SRD5A2, AR, and KROX20)were monitored. Fifty subjects were divided into a placebo group and a banana flower group. The experimental group consumed banana flower extract daily for twelve weeks and then underwent hair testing, hair-related genes analysis, collection of hair loss, and questionnaires. The results showed that the banana flower extract significantly increased hair cell growth and decreased the expression of ROS, DHT, and hair follicle growth inhibition-related SRD5A1, SRD5A2, and AR genes, and significantly increased the expression of hair growth-related KROX20 gene in HFDPCs. Consuming banana flower extract for twelve weeks increased the hair root diameter and reduced hair loss and scalp redness compared to the placebo group. Thus, banana flower extract(HappyAngel^(■))can stimulate hair growth and inhibit the activation of hair loss genes.

关键词： Banana flower Dihydrotestosterone Hair loss ROS Follicle dermal papilla cells

Fiber orientation effects on grinding characteristics and removal mechanism of 2.5D C_(f)/SiC composites

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第12期36卷 425-441页

作者： Cheng CAO Qinghua SONG Hui FU Hansong JI Zhanqiang LIU Liping JIANG Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of EducationSchool of Mechanical EngineeringShandong UniversityJinan 250061China National Demonstration center for Experimental Mechanical Engineering Education Shandong UniversityJinan 250061China Shandong Industrial Ceramic research&design Institute Zibo 255020China

Carbon fiber reinforced silicon carbide(C_(f)/SiC)composites are widely used in aerospace for their excellent mechanical properties.However,the quality of the machined surface is poor and unpredictable due to the material heterogeneity induced by complex removal mechanism.To clarify the effects of fiber orientation on the grinding characteristics and removal mechanism,single grit scratch experiments under different fiber orientations are conducted and a three-phase numerical modelling method for 2.5D C_(f)/SiC composites is proposed.Three fiber cutting modes i.e.,transverse,normal and longitudinal,are defined by fiber orientation and three machining directions i.e.,MA(longitudinal and normal),MB(longitudinal and transverse)and MC(normal and transverse),are selected to investigate the effect of fiber orientation on grinding force and micro-morphology.Besides,a three-phase cutting model of 2.5D C_(f)/SiC composites considering the mechanical properties of the matrix,fiber and interface is developed.Corresponding simulations are performed to reveal the micro-mechanism of crack initiation and extension as well as the material removal mechanism under different fiber orientations.The results indicate that the scratching forces fluctuate periodically,and the order of mean forces is MA>MC>MB.Cracks tend to grow along the fiber axis,which results in the largest damage layer for transverse fibers and the smallest for longitudinal fibers.The removal modes of transverse fibers are worn,fracture and peel-off,in which normal fibers are pullout and outcrop and the longitudinal fibers are worn and push-off.Under the stable cutting condition,the change of contact area between fiber and grit leads to different removal modes of fiber in the same cutting mode,and the increase of contact area results in the aggravation of fiber fracture.

关键词： 2.5D C_(f)/SiC composites Material removal mechanism Numerical modelling Single grit scratch experiments Surface morphology

Heavy metal pollution characteristics and health evaluation of farmland soil in a gold mine slag area of Luoyang in China

在线全文

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2021年第5期14卷 213-221页

作者： Hui Wang Hao Zhang Renkou Xu College of Chemical and Pharmaceutical Engineering Henan University of Science and TechnologyLuoyang 471023China Analysis and Testing center of Liming research&design Institute of Chemical Industry Co. Ltd.Luoyang 471001China State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China

The characteristics of eight heavy metals(lead,zinc,copper,nickel,chromium,cadmium,mercury and arsenic)in the surface soil of the historical slag area of the Au ore dressing plant in the South-West of Luoyang City were investigated and evaluated in terms of a pollution index,potential ecological hazards and health risks.The results showed that the average amounts of the heavy metals Pb,Zn and As in the soils of plots S3,S5,S7,S12 and S18 exceeded the soil pollution risk screening values.The Mero comprehensive pollution index in plots S7,S12 and S18 was greater than 3,indicating severe pollution.The severe pollution plot integrated the potential ecological risk index(RI)of each sampling point,which was in the order of RI_(S12)>RI_(S18)>RI_(S7)>RI_(S5)>RI_(S3).Among the heavy metals,Cd poses the greatest threat to ecological and human health.The effects of heavy metals in soil on the single non-carcinogenic health risk index(HQ)and the non-carcinogenic total risk index through three exposure pathways were in the order of HQ_(Hg)

关键词： historical slag area heavy metals pollution assessment health assessment farmland soil ecological hazard