检索结果-南通市图书馆

Stage identification and process optimization for fast drilling EDM of film cooling holes using KBSI method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Manufacturing 2023年第3期11卷 477-491页

作者： Jian Wang Xue-Cheng Xi ya-ou zhang Fu-Chun Zhao Wan-Sheng Zhao State Key Laboratory of Mechanical System and Vibration Shanghai 200240People's Republic of China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240People's Republic of China

Fast drilling electrical discharge machining(EDM)is widely used in the manufacture of film cooling holes of turbine ***,due to the various hole orientations and severe electrode wear,it is relatively intricate to accurately and timely identify the critical moments such as breakout,hole completion in the drilling process,and adjust the machining strategy *** breakout detection and hole completion determination methods are not suitable for the high-efficiency and fully automatic production of film cooling holes,for they almost all depend on preset thresholds or training data and become less appropriate when machining condition *** the breakout and hole completion detection problems can be abstracted to an online stage identification problem,in this paper,a kurtosis-based stage identification(KBSI)method,which uses a novel normalized kurtosis to denote the recent changing trends of gap voltage signals,is developed for online stage *** identification accuracy and generalization ability of the KBSI method have been verified in various machining *** improve the overall machining efficiency,the influence of servo control parameters on machining efficiency of each machining stage was analyzed experimentally,and a new stage-wise adaptive control strategy was then proposed to dynamically adjust the servo control parameters according to the online identification *** performance of the new strategy is evaluated by drilling film cooling holes at different hole *** results show that with the new control strategy,machining efficiency and the machining quality can be significantly improved.

关键词： Fast drilling electrical discharge machining(EDM) Film cooling holes Breakout detection Hole completion determination Stage identification Process optimization

Enhanced vision-transformer integrating with semi-supervised transfer learning for state of health and remaining useful life estimation of lithium-ion batteries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy and AI 2024年第3期17卷 380-396页

作者： ya-Xiong Wang Shangyu Zhao Shiquan Wang Kai ou Jiujun zhang School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350108China College of Materials Science and Engineering Fuzhou UniversityFuzhou 350108China

The state of health(SOH)and remaining useful life(RUL)of lithium-ion batteries are crucial for health management and ***,most data-driven estimation methods heavily rely on scarce labeled data,while traditional transfer learning faces challenges in handling domain shifts across various battery *** paper proposes an enhanced vision-transformer integrating with semi-supervised transfer learning for SOH and RUL estimation of lithium-ion batteries.A depth-wise separable convolutional vision-transformer is developed to extract local aging details with depth-wise convolutions and establishes global dependencies between aging information using multi-head *** mean discrepancy is employed to initially reduce the distribution difference between the source and target domains,providing a superior starting point for fine-tuning the target domain ***,the abundant aging data of the same type as the target battery are labeled through semi-supervised learning,compensating for the source model's limitations in capturing target battery aging *** regularization incorporates the cross-entropy between predictions with and without adversarial perturbations into the gradient backpropagation of the overall *** particular,across the experimental groups 13–15 for different types of batteries,the root mean square error of SOH estimation was less than 0.66%,and the mean relative error of RUL estimation was 3.86%.Leveraging extensive unlabeled aging data,the proposed method could achieve accurate estimation of SOH and RUL.

关键词： State of health(S0H) Remaining useful life(RUL) Depth-wise separable convolutional vision-transformer Transfer learning Maximum mean discrepancy Semi supervised learning

Development of a convolutional neural network based geomechanical upscaling technique for heterogeneous geological reservoir

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 Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2111-2125页

作者： Zhiwei Ma Xiaoyan ou Bo zhang Earth and Environmental Sciences Division Los Alamos National LaboratoryLos AlamosUSA Civil and Environmental Engineering University of AlbertaEdmontonCanada

Geomechanical assessment using coupled reservoir-geomechanical simulation is becoming increasingly important for analyzing the potential geomechanical risks in subsurface geological ***,a robust and efficient geomechanical upscaling technique for heterogeneous geological reservoirs is lacking to advance the applications of three-dimensional(3D)reservoir-scale geomechanical simulation considering detailed geological ***,we develop convolutional neural network(CNN)proxies that reproduce the anisotropic nonlinear geomechanical response caused by lithological heterogeneity,and compute upscaled geomechanical properties from CNN *** CNN proxies are trained using a large dataset of randomly generated spatially correlated sand-shale realizations as inputs and simulation results of their macroscopic geomechanical response as *** trained CNN models can provide the upscaled shear strength(R^(2)>0.949),stress-strain behavior(R^(2)>0.925),and volumetric strain changes(R^(2)>0.958)that highly agree with the numerical simulation results while saving over two orders of magnitude of computational *** is a major advantage in computing the upscaled geomechanical properties directly from geological realizations without the need to perform local numerical simulations to obtain the geomechanical *** proposed CNN proxybased upscaling technique has the ability to(1)bridge the gap between the fine-scale geocellular models considering geological uncertainties and computationally efficient geomechanical models used to assess the geomechanical risks of large-scale subsurface development,and(2)improve the efficiency of numerical upscaling techniques that rely on local numerical simulations,leading to significantly increased computational time for uncertainty quantification using numerous geological realizations.

关键词： Upscaling Lithological heterogeneity Convolutional neural network(CNN) Anisotropic shear strength Nonlinear stressestrain behavior

Entangled photons enabled ultrafast stimulated Raman spectroscopy for molecular dynamics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2024年第8期13卷 1615-1622页

作者： Jiahao Joel Fan Zhe-Yu ou Zhedong zhang Department of Physics City University of Hong KongKowloonHong Kong SARChina City University of Hong Kong Shenzhen Research InstituteShenzhenGuangdongChina

Quantum entanglement has emerged as a great resource for studying the interactions between molecules and *** propose a new scheme of stimulated Raman scattering with entangled photons.A quantum ultrafast Raman spectroscopy is developed for condensed-phase molecules,to monitor the exciton populations and *** results are obtained,showing an entanglement-enabled time-frequency scale not attainable by classical *** Raman signal presents an unprecedented selectivity of molecular correlation functions,as a result of the Hong-ou-Mandel *** work suggests a new paradigm of using an unconventional interferometer as part of spectroscopy,with the potential to unveil advanced information about complex materials.

关键词： materials spectroscopy selectivity

Alleviating the anisotropic microstructural change and boosting the lithium ions diffusion by grain orientation regulation for Ni-rich cathode materials

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 Energy Chemistry 2024年第1期88卷 213-222,I0005页

作者： Xinyou He Shilin Su Bao zhang Zhiming Xiao Zibo zhang Xing ou Engineering Research Center of the Ministry of Education for Advanced Battery Materials School of Metallurgy and EnvironmentCentral South UniversityChangsha 410083HunanChina Zhejiang Power New Energy Co.Ltd Zhuji 311899ZhejiangChina

Generally,layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary *** the arrangement of primary particles plays a very important role in the properties of Ni-rich *** disordered particle arrangement is harmful to the cyclic performance and structural stability,yet the fundamental understanding of disordered structure on the structural degradation behavior is ***,we have designed three kinds of LiNi_(0.83)Co_(0.06)Mn_(0.11)O_(2) cathode materials with different primary particle orientations by regulating the precursor coprecipitation *** finite element simulation and in-situ characterization,the Li^(+)transport and structure evolution behaviors of different materials are ***,the smooth Li^(+)diffusion minimizes the reaction heterogeneity,homogenizes the phase transition within grains,and mitigates the anisotropic microstructural change,thereby modulating the crack evolution ***,the optimized structure evolution ensures radial tight junctions of the primary particles,enabling enhanced Li^(+)diffusion during dynamic ***-loop bidirectional enhancement mechanism becomes critical for grain orientation regulation to stabilize the cyclic *** precursor engineering with particle orientation regulation provides the useful guidance for the structural design and feature enhancement of Ni-rich layered cathodes.

关键词： Ni-rich cathode Grain orientation regulation Anisotropic microstructural change Precursor engineering Li~+-ions diffusion

Effect of WeiJia on carbon tetrachloride induced chronic liver injury

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

World Journal of Gastroenterology 2006年第12期12卷 1912-1917页

作者： Pik-Yuen Cheung Qizhang Gan-Rong Bai Chi-Chun Fong Lin Shi Yue-Feng Shi Meng-Suyang DepartmentofBiology ya-ou zhang Marie Chia-Mi Lin Bernard Chan Jay Chun Hsiang-Fu Kung Department of Biology and Chemistry City University of Hong Kong 83 Tat Chee AvenuKowloonHong Kong SARChina Life Science Division Tsinghua University Graduate School at ShenzhenTsinghua CampusUniversity TownShenzhenChina Institute of Molecular Biology The University of Hong KongPokfulamHong KongSARChina Life Tec Enterprise Limited CentralHong KongSARChina The Centre for Emerging Infectious Diseases Faculty of MedicineThe Chinese University of Hong KongShatinN.T.Hong Kong SARChina

AIM： To study the effect of WeiJia on chronic liver injury using carbon tetrachloride （CCh） induced liver injury animal model. METHODS： Wistar rats weighing 180-220g were randomly divided into three groups： normal control group （Group A）, CCh induced liver injury control group （Group B） and CCI4 induction with WeiJia treatment group （Group C）. Each group consisted of 14 rats. Liver damage and fibrosis was induced by subcutaneous injection with 40% CCh in olive oil at 3 mL/kg body weight twice a week for eight weeks for Groups B and C rats whereas olive oil was used for Group A rats. Starting from the third week, Group C rats also received daily intraperitoneal injection of *** at a dose of 1.25 μg/kg body weight. Animals were sacrificed at the fifth week （4 male, 3 female）, and eighth week （4 male, 3 female） respectively. Degree of fibrosis were measured and serological markers for liver fibrosis and function including hyaluronic acid （HA）, type Ⅳ collagen （CIV）, γ-glutamyl transferase （γ-GT）, alanine aminotransferase （ALT） and aspartate aminotransferase （AST） were determined. Alpha smooth muscle actin （α-SMA） and proliferating cell nuclear antigen （PCNA） immunohistochemistry were also performed. RESULTS： CCl4 induction led to the damage of liver and development of fibrosis in Group B and Group C rats when compared to Group A rats. The treatment of WeiJia in Group C rats could reduce the fibrosis condition significantly compared to Group B rats. The effect could be observed after three weeks of treatment and was more obvious after eight weeks of treatment. Serum HA, CIV,ALT, AST and γ-GT levels after eight weeks of treatment for Group C rats were 58±22 μg/L （P〈0.01）, 57±21 μg/L （P〈0.01）, 47±10 U/L （P〈0.01）, 139±13 U/L （P〈0.05） and 52±21 U/L （P〉0.05） respectively, similar to normal control group （Group A）, but significantly different from CCh induced liver injury control group （Group B）. An increase in PCNA and decrease in α-SMA expression level was also obs

关键词： WeiJia Carbon tetrachloride Liver fibrosis

Examining the Spatiotemporal Dynamics and Determinants of Land Urbanization in Prefecture-level Cities,China

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 Geographical Science 2024年第1期34卷 19-33页

作者： yaNG Zhen ZHU Huxiao zhang Xinlin ou Xiangjun School of Geography Geomatics and Planning&Urban-rural Integration Development Research InstituteJiangsu Normal UniversityXuzhou221116China

Examining the spatiotemporal dynamics and determinants of land urbanization is critical for promoting healthy urban development and the rational use of land *** on the dataset consisting of land use change data and selected factors in 2010 and2020,this study used visual analysis to reveal the spatiotemporal dynamics of land urbanization across prefecture-level cities in ***,the driving forces underlying land urbanization were examined by using geographical detector *** are the findings:1)we find that there exist notable spatial variances in land urbanization across prefecture-level ***,the differentiation in land urbanization between the northern and southern cities is more pronounced than that between the coastal and inland cities,or between the eastern and western ***-level cities located in central and western China have experienced the most rapid growth in land ***,the growth rate in northeastern China is the lowest,while the velocity in eastern China remains relatively *** using spatial autocorrelation analysis,this study reveals that the land urbanization level in prefecture-level cities has significant spatial agglomeration.2)We further find that land urbanization in China is influenced by factors related to urban land supply and demand,and urban population growth,economic growth,land financial and political incentive have greater impact on land urbanization than other factors.3)We also find that the impacts of determinants on China’s land urbanization vary over time,the explanatory power of economic development increased,while the explanatory power of state forces *** argue that integrating the supply and demand factors of land urbanization can provide a more comprehensive understanding of the driving mechanisms underlying land urbanization in China and other transitional countries,and help decision-makers in these countries formulate more detailed and specif

关键词： land urbanization spatial pattern influencing factor geographical detector China

Heat dissipation of carbon shell in ZrC-SiC/TaC coating to improve protective ability against ultrahigh temperature ablation

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

Journal of Advanced Ceramics 2024年第7期13卷 1080-1091页

作者： Yuyu zhang Xuemeng zhang Hongkang ou Bozhe Wang Jia Sun Qiangang Fu Science and Technology on Thermostructural Composite Materials Laboratory Shaanxi Key Laboratory of Fiber Reinforced Light-Weight CompositesNorthwestern Polytechnical UniversityXi’an 710072China System Design Institute of Hubei Aerospace Technology Academy Wuhan 430040China

To efficiently decrease ablation heat accumulation and improve the ability of ZrC-SiC/TaC coatings to protect carbon/carbon(C/C)composites,a thermally conductive nanonetwork with a ceramic@carbon core-shell structure was designed and ***-derived SiC/TaC with a graphene carbon shell was synthesized and introduced into a ZrC coating by supersonic atmospheric plasma spraying(SAPS).Graphene shell paths increased the heat transfer capability by lowering the surface temperature to approximately 200℃during oxyacetylene *** heat dissipation of the graphene shell in the ZrC-SiC/TaC@C coating reduced the volatilization of low-melting-point phases and delayed the sintering of ZrO_(2) ***,the graphene shell in ZrC-SiC/TaC@C coating decreased the mass and linear ablation rates by 91.4%and 93.7%compared to ZrC-SiC/TaC coating,*** work provided a constructive idea for improving the ablation resistance of the coatings by incorporating carbon nanomaterials as a function of heat dissipation.

关键词： carbon/carbon(C/C)composites carbon nanomaterials core-shell structure polymer-derived ceramic(PDC) ablation resistance

Luminescence and magnetic properties of bifunctional nanoparticles composited by nitrogen-doped graphene quantum dots and gadolinium

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 Rare Earths 2024年第4期42卷 716-723页

作者： Wanli zhang Hao Zhou Meigui ou Donghao Sun Chunlin yang College of Materials and Metallurgy University of GuizhouGuiyang550025China National Local Co-construction Engineering Laboratory for High Performance Metal Structure Material and Manufacture Technology Guiyang550025 China College of Chemistry and Materials Engineering Guiyang UniversityGuiyang550003China

In this paper,nitrogen-doped graphene quantum dots(N-GQDs)were combined with gadolinium ions(Gd^(3+))by a surface modification to obtain magneto-optical dual-functional N-GQDs/Gd^(3+)*** morphology of obtained composite was characterized by field emission scanning electron microscopy and transmission electron *** and magnetic properties were measured by a fluorescence spectrophotometer and a vibrating sample magnetometer,*** indicate that well-dispersed spherical N-GQDs/Gd^(3+)nanoparticles have an average diameter of 7 nm.N-doping significantly increases the luminesce nce of particles with an optimal luminescence intensity at 20℃and pH=9.X-ray photoelectron spectroscopy results indicate that the N-doping introduces pyrrolic N as an electron donor,enhancing fluorescence by increasing the surface electron cloud density of *** addition,density functional theory calculation results reveal that N-doping reduces the band gap of NGQDs/Gd^(3+),enabling electronic transitions to higher energy levels and generating more activation sites,thereby enhancing *** to N-GQDs/Gd^(3+)prepared at 20℃,the saturated magnetization of particles prepared at 40℃is 0.85 emu/g,indicating a better magnetic *** above results suggest that bifunctional nanomaterials N-GQDs/Gd^(3+)with excellent optical properties and magnetism can be better used for fluorescence and magnetic resonance imaging.

关键词： Nitrogen-doped graphenequantum dots Gadolinium Luminescence Magnetism Rare earths