检索结果-南通市图书馆

co.stitutive model of visco.lastic dynamic damage for the material of gas obturator in modular-charge howitzer

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence technology（防务技术） 2024年第9期39卷 203-216页

作者： Zhonggang Li Longmiao Chen Yifan Li Yufeng Jia Quan Zhang School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China technology center Shanxi North Machine-building Co.Ltd.Taiyuan 030009China Research and Development Department Kelong New Material Technology Co.Ltd.Xianyang 712000China

In order to investigate the mechanical response behavior of the gas obturator of the breech mechanism,made of polychloroprene rubber(PCR), uniaxial co.pression experiments were carried out by using a universal testing machine and a split Hopkinson pressure bar(SHPB), obtaining stress-strain responses at different temperatures and strain rates. The results revealed that, in co.parison to other polymers, the gas obturator material exhibited inco.spicuous strain softening and hardening effects;meanwhile, the mechanical response was more affected by the strain rate than by temperature. Subsequently, a succinct visco.lastic damage co.stitutive model was developed based on the ZWT model, including ten undetermined parameters, formulated with inco.porating three parallel co.ponents to capture the visco.lastic response at high strain rate and further enhanced by integrating a three-parameter Weibull function to describe the damage. co.pared to the ZWT model, the modified model co.ld effectively describe the mechanical response behavior of the gas obturator material at high strain rates. This research laid a theoretical foundation for further investigation into the influence of chamber sealing issues on artillery firing.

关键词： Breech mechanism Gas obturator Polychloroprene rubber co.stitutive model Strain rate Damage

Tungsten separation behavior on preparation of high-purity cerium by co.bined vacuum gravity sedimentation-directional solidification

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第6期42卷 1182-1186,I0007页

作者： Dongwei Zhang Wenli Lu Minglei Xu Dehong Chen Xiaowei Zhang Chuang Yu Wensheng Yang Ruifeng Dong Zhiqiang Wang Liguo Han Zengdong Pang GRIREM Hi-Tech co. Ltd.Langfang065201China National Engineering Research center for Rare Earth China GRINM Group Co.Ltd.Beijing100088China GRIREM Advanced Materials co. Ltd.Beijing100088China

In light of the difficult removal of harmful impurity tungsten(W)in Ce metal,in this paper a co.bined vacuum gravity sedimentation-directional solidification method was innovatively designed and the W separation behavior was *** reducing the electron beam power instantly and gradually at reduction rates of 1,3 and 5 kW/min,it is found that W is enriched at the bottom of ingots as the melt *** enrichment effect is much better than that of single purification method and the enrichment degree increases as the beam reduction rate decreases,attributed to the k0(W)>1 andρ(W)>ρ(Ce).Overall,the minimum co.tent of W impurity can decrease from 630 to 0.1 ppm at the top of the ingot,and the purity of Ce increases from 99.932 wt%to 99.995 wt%by this co.bined ***,this paper provides a new method for the removal of high density and low evaporation co.fficient impurities in low vapor pressure rare earth metals.

关键词： Cerium Electron beam melting Directional solidification Gravity sedimentation Rare earths

Current status and development of CMOS SiPM for scintillator-based radiation detectors toward all-digital sensors[Invited]

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2024年第2期22卷 17-27页

作者： Nico.a D'Ascenzo 胡文韬劳慧华越轩张博房磊奚道明郑睿邱奥 Emanuele Antonecchia 凌怡清刘雨晴李琰俞航肖鹏谢庆国 Wuhan National Laboratory for Optoelectronics Wuhan 430074China Biomedical Engineering Department Huazhong University of Science and TechnologyWuhan 430074China RAYQUANT technology co. Ltd.Ezhou 436044China RAYSOLUTION Healthcare co. Ltd.Hefei 230000China RAYMEASURE technology co. Ltd.Suzhou 215000China RAYCAN technology co. Ltd.Suzhou 215000China co.lege of co.puter Science and Software Engineering Shenzhen UniversityShenzhen 518060China

Modern scintillator-based radiation detectors require silico. photomultipliers(Si PMs)with photon detection efficiency higher than 40%at 420 nm,possibly extended to the vacuum ultraviolet(VUV)region,single-photon time resolution(SPTR)co.nt rate(DCR)co.centrations at low CMOS scales,deep-level carrier generation in shallow trench isolation fabrication,and power co.sumption,among *** advances at 350 and 110 nm CMOS nodes are benchmarked against available Si PMs obtained in CMOS and co.mercial customized *** co.cept of digital multithreshold Si PMs with a single microcell readout is finally reported,proposing a possible direction toward fully digital scintillator-based radiation detectors.

关键词： silico. photomultiplier co.plementary metal-oxide semico.ductor digital SiPM

Occurrence and vertical distribution of aluminum and rare earths in weathered crust elution-deposited rare earth ore:Effect of soil solution pH and clay minerals

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第7期42卷 1394-1402,I0007页

作者： Jiaxin Pan Longsheng Zhao Zheng Li Xiaowei Huang Zongyu Feng Jun Chen National Engineering Research center for Rare Earth China GRINM Group Co.Ltd.Beijing100088China School of Metallurgical and Eco.ogical Engineering University of Science and Technology Beijing(USTB)Beijing100083China GRIREM Hi–Tech co. Ltd.Langfang065201China GRIREM Advanced Materials co. Ltd.Beijing100088China GRIMAT Engineering Institute co. Ltd.Beijing101407China

Weathered crust elution-deposited rare earth ore is crucial source of medium and heavy rare earths,with in-situ leaching being the most co.mon mining *** high co.tents of impurity of aluminum in the leach solution are a significant challenge for the subsequent enrichment process of rare earths.A co.prehensive understanding of the occurrences and vertical distribution of aluminum and rare earths within typical vertical profiles can provide valuable insights into entire design of the in-situ *** paper improves a five-step sequential extraction method to analyze the occurrence and vertical distribution of rare earths and aluminum in vertical profiles from Chongzuo and *** results demonstrate that soil solution pH is the main factor affecting the vertical distribution of ionexchangeable rare *** samples have distinct areas of enrichment for ion-exchangeable rare earths or ***-exchangeable rare earths are primary co.centrated in the middle and lower parts of the ore layer(4-13 m in Chongzuo,14-22 m in Longyan),while the ion-exchangeable aluminum is mainly enriched in the upper part of the ore layer(1-5 m in Chongzuo,and 2-14 m in Longyan).The vertical distribution of inorganic hydroxy aluminum is likely influenced by the micromorphology and particle size of the clay *** inorganic hydroxy aluminum co.centration in Chongzuo samples decreases co.tinuously from 415.65 to 120.95 mg/kg with increasing sampling depth,whereas the co.centration in Longyan samples(110.55-171.27 mg/kg)is almost independence with sampling *** results provide direct guidance for the entire design of the injection well depth and the leaching parameters,thereby inhibiting the leaching of impurity of aluminum and lower the co.sumption of leaching agent.

关键词： Weathered crust elution-deposited rare earth ore Sequential extraction Occurrence Aluminum Rare earth elements

Carbon efficiency modeling and optimization of solar-powered cellular networks

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第5期67卷 228-243页

作者： Yuxi ZHAO Xiaohu GE Wen YAN Tao HAN Yi ZHONG School of Electronic Information and co.munications Huazhong University of Science and Technology Huawei technology co. Ltd.

As wireless co.munication traffic experiences rapid growth, the carbon emissions caused by the co.munication industry are also on the rise. To achieve “carbon neutrality”, researchers are co.sidering the use of renewable energy sources to power cellular networks, thereby reducing carbon emissions. However, a challenge arises when using renewable energy, specifically owing to the unpredictable nature of both the energy co.sumption of the cellular network and the power generation from renewable sources. This inco.sistency results in low renewable energy utilization and reduced carbon efficiency. Herein, we co.struct a carbon efficiency model of solar-powered cellular networks using practical data from solar radiation. We propose a mechanism that alternately optimizes the performance of the renewable energy network and the cellular network. This approach is based on co.vex optimization theory and the Dinkelback algorithm, and it leads to the design of a carbon efficiency optimization algorithm. This algorithm aims to improve the carbon efficiency of cellular networks and reduce their carbon emissions. Simulation results demonstrate that our optimization scheme yields a maximum improvement of 2.56 × 108bps/g in the carbon efficiency of the cellular network as co.pared to co.ventional power allocation schemes such as the traditional water filling method and heuristic energy sharing and charge/discharge algorithms.

关键词： cellular networks renewable energy carbon efficiency co.vex optimization theory dinkelbach

An Image Fingerprint and Attention Mechanism Based Load Estimation Algorithm for Electric Power System

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

co.puter Modeling in Engineering & Sciences 2024年第7期140卷 577-591页

作者： Qing Zhu Linlin Gu Huijie Lin Electricity technology Branch Nari Technology Co.Ltd.Nanjing211106China NARI-TECH Nanjing co.trol Systems co. Ltd.Nanjing211106China

With the rapid development of electric power systems,load estimation plays an important role in system operation and ***,load estimation techniques co.tain traditional,time series,regression analysis-based,and machine learning-based *** the machine learning-based method can lead to better performance,in this paper,a deep learning-based load estimation algorithm using image fingerprint and attention mechanism is ***,an image fingerprint co.struction is proposed for training *** the data preprocessing,the training data matrix is co.structed by the cyclic shift and cubic spline ***,the linear mapping and the gray-co.or transformation method are proposed to form the co.or image ***,a co.volutional neural network(CNN)co.bined with an attentionmechanism is proposed for training performance *** last,an experiment is carried out to evaluate the estimation *** with the support vector machine method,CNN method and long short-term memory method,the proposed algorithm has the best load estimation performance.

关键词： Load estimation deep learning attention mechanism image fingerprint co.struction

Performance Study of the MPC based on BPNN Prediction Model in Thermal Management System of Battery Electric Vehicles

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 Thermal Science 2024年第6期33卷 2318-2335页

作者： HE Lian'ge JING Haodong ZHANG Yan LI Pengpai GU Zihan Key Laboratory of Advanced Manufacture technology for Automobile Parts(Chongqing University of technology) Ministry of Education Ningbo Shenglong Group co. Ltd. Chongqing Tsingshan Industrial co. Ltd.

In this paper,a model predictive co.trol(MPC) based on back propagation neural network(BPNN)prediction model was proposed for co.pressor speed co.trol of air co.ditioning system(ACS) and battery thermal management system(BTMS) co.pling system of battery electric vehicle(BEV).In order to solve the problem of high co.ling energy co.sumption and inferior thermal co.fort in the cabin of the battery electric vehicle thermal management system(BEVTMS) during summer time,this paper co.bines the respective superiorities of artificial neural network(ANN) predictive modeling and MPC,and creatively co.bines the two methods and uses them in the co.trol of ***,based on ANN and heat transfer theory,BPNN prediction model,ACS and BTMS co.pling system were established and ***,a mathematical method of MPC was established to co.trol the speed of the ***,the state parameters of the co.pled system were predicted using a BPNN prediction model,and the predicted values were passed to the MPC,thus achieving accurate co.trol of the co.pressor speed using the ***,the effects of PID co.trol and MPC based on BPNN prediction model on thermal co.fort of cabin and co.pressor energy co.sumption at different ambient temperatures were co.pared in simulation under New European Driving Cycle(NEDC) *** results showed for the co.structed BPNN prediction model predicted and tested values of the selected parameters the mean squared error(MSE) ranged from 2.498% to 8.969%,mean absolute percentage error(MAPE) ranged from 4.197% to 8.986%,and mean absolute error(MAE) ranged from 3.202% to 8.476%.At ambient temperatures of 25℃,35℃ and 45℃,the MPC based on the BPNN prediction model reduced the cumulative disco.fort time in the cabin by 100 s,39 s and 19 s,respectively,co.pared with the PID *** three NEDC co.ditions,the energy co.sumption is reduced by 1.82%,2.35% and 3.48%,*** the ambient temperature was 35℃,the MPC based on BPNN pre

关键词： air co.ditioning system back propagation neural network battery electric vehicle battery thermal management system model predictive co.trol

Solidification behaviour and hot cracking susceptibility of a novel Ni-based superalloy

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第4期31卷 956-966页

作者： Yue Chen Shao-min Lv Xing-fei Xie Xiao-can Wen Jng-long Qu Jin-hui Du High-Temperature Materials Institute China Iron and Steel Research Institute Group Co.Ltd.Beijing 100081China Beijing GAONA Materials and technology co. Ltd.Beijing 100081China Sichuan CISRI-GAONA Forging co. Ltd.Deyang 610000SichuanChina

A novel Ni-based superalloy GH4151,with a γ′ volume fraction of about 55%and a service temperature capability up to 8oo oC,was *** to the different co.ling co.ditions of various regions during the solidification of ingots,significant co.ling rate variations may lead to the occurrence of hot *** scanning laser microsco.e was utilised to investigate the solidification process and phase precipitation behaviour of the GH4151 under wide range co.ling *** characteristics of L→γ transformation were analysed,and the growth rates of at each stage were *** segregation behaviour was predicted using the Scheil equation,and the predicted results match well with the experimental *** sensitivity co.fficient for hot cracking was modified,and cracking sensitivity co.fficient values for the alloy under different co.ling rates were co.puted,revealing that the alloy is most susceptible to hot cracking at 10℃/min co.ling ***,co.trolling the co.ling rate can reduce the possibility of hot cracking in ingot.

关键词： Ni-based superalloy Solidification behaviour In-situ observation Clyne and Davies's criterion:Hot cracking susceptibility

A Gel-Based Solidification technology for Large Fracture Plugging

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Fluid Dynamics & Materials Processing 2024年第3期20卷 563-578页

作者： Kunjian Wang Ruibin He Qianhua Liao Kun Xu Wen Wang Kan Chen Tianjin Branch of CNOOC(China)co. Ltd.Tianjin300450China Jingzhou Jiahua technology co. Ltd.Jingzhou434001China

Fault fractures usually have large openings and co.siderable extension. Acco.dingly, cross-linked gel materials aregenerally co.sidered more suitable plugging agents than water-based gels because the latter often undergo co.taminationvia formation water, which prevents them from being effective over long times. Hence, in this study, aset of oil-based co.posite gels based on waste grease and epoxy resin has been developed. These materials havebeen observed to possess high co.pressive strength and resistance to the aforementioned co.tamination, therebyleading to notable increase in plugging success rate. The co.pressive strength, thickening time, and resistance toformation water pollution of these gels have been evaluated indoors. The results show that the co.pressivestrength of the gel can reach 11 MPa;additionally, the related gelation time can be co.trolled to be more than3 h, thereby providing a safe co.struction time;Invasion of formation water has a small effect on the gel strengthand does not shorten the thickening time. All co.sidered performance indicators of the oil-based gel co.firm itssuitability as a plugging agent for fault fractures.

关键词： Drilling loss fault fracture oil-based gel co.pressive strength gel plugging