检索结果-南通市图书馆

Influence of temperature and alloying elements on the threshold displacement energies in concentrated Ni-Fe-Cr alloys

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第5期30卷 106-113页

作者： shijun zhao Department of Mechanical Engineering City University of Hong KongHong KongChina

Concentrated solid-solution alloys(CSAs)have demonstrated promising irradiation resistance depending on their *** irradiation,various defects can be *** of the most important parameters characterizing the defect production and the resulting defect number is the threshold displacement energies(Ed).In this work,we report the results of Ed values in a series of Ni-Fe-Cr concentrated solid solution alloys through molecular dynamics(MD)*** on several different empirical potentials,we show that the differences in the Ed values and its angular dependence are mainly due to the stiffness of the potential in the intermediate *** influences of different alloying elements and temperatures on Ed values in different CSAs are further evaluated by calculating the defect production *** results suggest a limited influence of alloying elements and temperature on Ed values in concentrated ***,we discuss the relationship between the primary damage and Ed values in different ***,this work presents a thorough study on the Ed values in concentrated alloys,including the influence of empirical potentials,their angular dependence,temperature dependence,and effects on primary defect production.

关键词： irradiation effects molecular dynamics threshold displacement energies concentrated high-entropy alloys

Visibility Characteristics over the South China Sea during 1980-2018 Based on Gridded Data Generated by Artificial Neural Network

在线全文

学校读者我要写书评

暂无评论

Journal of Meteorological Research 2021年第4期35卷 690-700页

作者： Lifeng LI Yulong SHAN shijun zhao School of Meteorology and Oceanography National University of Defense TechnologyChangsha 430073

This paper generated gridded visibility(Vis)data from 1980 to 2018 over the South China Sea(SCS)based on artificial neural network(ANN),and the accuracy of the generated data was ***,temporal and spatial characteristics of Vis in the area were analyzed based on the generated Vis *** results showed that Vis in the southern SCS was generally better than that in the northern *** the past 39 years,Vis in both spring and winter has improved,especially in winter at a significant increased speed of 0.37 km decade^(-1).However,Vis in both summer and autumn has decreased,especially in summer with an obvious reduction of 0.84 km decade^(-1).Overall,Vis is best in summer and worst in winter,averaging 31.89 km in summer and 20.96 km in winter,which may be related to the difference of climatic conditions and wind speed in different *** the same time,probability of low Vis in spring is significantly higher than that in other seasons,especially in the northwest of Hainan Island and the northwest of Malaysia.

关键词： visibility(Vis) spatiotemporal characteristics South China Sea

Prediction of visibility in the Arctic based on dynamic Bayesian network analysis

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2022年第4期41卷 57-67页

作者： shijun zhao Yulong Shan Ismail Gultepe College of Meteorology and Oceanography National University of Defense TechnologyNanjing 211101China Cloud Physics and Severe Weather Research Environment and Climate Change CanadaToronto M4Y1M7Canada

With the accelerated warming of the world,the safety and use of Arctic passages is receiving more *** visibility in the Arctic has been a hot topic in recent years because of navigation risks and opening of ice-free northern *** weather prediction and statistical prediction are two methods for predicting *** microphysical parameterization schemes for visibility are so sophisticated,visibility prediction using numerical weather prediction models includes large *** the development of artificial intelligence,statistical prediction methods have received increasing *** this study,we constructed a statistical model with a physical basis,to predict visibility in the Arctic based on a dynamic Bayesian network,and tested visibility prediction over a 1°×1°grid area averaged *** results show that the mean relative error of the predicted visibility from the dynamic Bayesian network is approximately 14.6%compared with the inferred visibility from the artificial neural ***,dynamic Bayesian network can predict visibility for only 3 ***,with an increase in predicted area and period,the uncertainty of the predicted visibility becomes *** the same time,the accuracy of the predicted visibility is positively correlated with the time period of the input evidence *** is concluded that using a dynamic Bayesian network to predict visibility can be useful over Arctic regions for projected climatic changes.

关键词： Arctic visibility prediction artificial neural network dynamic Bayesian network

Sub-Homogeneous Peridynamic Model for Fracture and Failure Analysis of Roadway Surrounding Rock

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第6期139卷 3167-3187页

作者： shijun zhao Qing Zhang Yusong Miao Weizhao Zhang Xinbo zhao Wei Xu School of Science Qingdao University of TechnologyQingdao266520China College of Mechanics and Materials Hohai UniversityNanjing211100China Xibei Mining Co. Ltd.Shandong Energy GroupXi’an710018China

The surrounding rock of roadways exhibits intricate characteristics of discontinuity and *** address these complexities,this study employs non-local Peridynamics(PD)theory and reconstructs the kernel function to represent accurately the spatial decline of long-range ***,modifications to the traditional bondbased PD model are *** considering the micro-structure of coal-rock materials within a uniform discrete model,heterogeneity characterized by bond random pre-breaking is *** approach facilitates the proposal of a novel model capable of handling the random distribution characteristics of material heterogeneity,rendering the PD model suitable for analyzing the deformation and failure of heterogeneous layered coal-rock mass *** established numerical model and simulation method,termed the sub-homogeneous PD model,not only incorporates the support effect but also captures accurately the random heterogeneous micro-structure of roadway surrounding *** simulation results obtained using this model show good agreement with field measurements from the Fucun coal mine,effectively validating the model’s capability in accurately reproducing the deformation and failure mode of surrounding rock under bolt-supported(anchor cable).The proposed subhomogeneous PD model presents a valuable and effective simulation tool for studying the deformation and failure of roadway surrounding rock in coal mines,offering new insights and potential advancements.

关键词： Roadway surrounding rock peridynamics heterogeneous material fracture analysis numerical simulation

Formal analysis of TPM2.0 key management APIs

维普期刊数据库评论

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 Science Bulletin 2014年第32期59卷 4210-4224页

作者： Qianying Zhang shijun zhao Yu Qin Dengguo Feng Trusted Computing and Information Assurance Laboratory Institute of Software Chinese Academy of Sciences

The trusted platform module(TPM),a system component implemented on physical resources,is designed to enable computers to achieve a higher level of security than the security level that it is possible to achieve by software *** this reason,the TPM provides a way to store cryptographic keys and other sensitive data in its memory,which is shielded from access by any entity other than the *** who want to use those keys and data to achieve some security goals are restricted to interact with the TPM through its APIs defined in the TPM ***,whether the TPM can provide Protected Capabilities it claimed depends to a large extent on the security of its *** this paper,we devise a formal model,which is accessible to a fully mechanized analysis,for the key management APIs in the TPM2.0 *** identify and formalize security properties of these APIs in our model and then successfully use the automated prover Tamarin to obtain the first mechanized analysis of *** analysis shows that the key management subset of TPM APIs preserves the secrecy of non-duplicable keys for unbounded numbers of fresh keys and *** analysis also reports that the key duplication mechanism,used to duplicate a key between two hierarchies,is vulnerable to impersonation attacks,which enable an adversary to recover the duplicated key of the originating hierarchy or import his own key into the destination *** at avoiding these vulnerabilities,we proposean approach,which restricts the originating and destination TPMs to authenticate each other’s identity during *** we formally demonstrate that our approach maintains the secrecy of duplicable keys when they are duplicated.

关键词：密钥管理 API 形式分析自动校准装置 TPM 安全级别物理资源敏感数据

Local-environment dependence of stacking fault energies in concentrated solid-solution alloys

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2019年第1期5卷 1032-1038页

作者： shijun zhao Yuri Osetsky G.Malcolm Stocks Yanwen Zhang Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTN 37831USA Department of Mechanical Engineering City University of Hong KongHong KongChina Department of Materials Science and Engineering University of TennesseeKnoxvilleTN 37996USA

Concentrated solid-solution alloys(CSAs)based on 3d transition metals have demonstrated extraordinary mechanical properties and radiation resistance associated with their low stacking fault energies(SFEs).Owing to the intrinsic disorder,SFEs in CSAs exhibit distributions depending on local atomic *** this work,the distribution of SFEs in equiatomic CSAs of NiCo,NiFe,and NiCoCr are investigated based on empirical potential and first-principles *** show that the calculated distribution of SFEs in chemically disordered CSAs depends on the stacking fault area using empirical potential *** on electronic structure calculations,we find that local variations of SFEs in CSAs correlate with the charge density redistribution in the stacking fault *** further propose a bond breaking and forming model to understand and predict the SFEs in CSAs based on the local structure *** is shown that the perturbation induced by a stacking fault is localized in the first-nearest planes for NiCo,but extends up to the third nearest planes for NiFe and NiCoCr because of partially filled d electrons in Fe and Cr.

关键词： alloys fault stacking

A STAMP-Game model for accident analysis in oil and gas industry

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2024年第3期21卷 2154-2167页

作者： Huixing Meng Xu An Daiwei Li shijun zhao Enrico Zio Xuan Liu Jinduo Xing State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of TechnologyBeijing100081China School of Emergency Management and Safety Engineering China University of Mining and Technology(Beijing)Beijing100083China Energy Department Politecnico di MilanoVia La Masa 34Milan20156Italy Mines Paris PSL Centre de Recherche sur les Risques et les CrisesSophie Antipolis06904France School of Mechanical-Electronic and Vehicle Engineering Beijing University of Civil Engineering and ArchitectureBeijing100044China

Accidents in engineered systems are usually generated by complex socio-technical *** is beneficial to investigate the increasing complexity and coupling of these factors from the perspective of system *** on system and control theories,System-Theoretic Accident Model and Processes(STAMP)is a widely recognized approach for accident *** this paper,we propose a STAMP-Game model to analyze accidents in oil and gas storage and transportation *** in accident analysis by STAMP can be regarded as players of a *** theory can,thus,be adopted in accident analysis to depict the competition and cooperation between ***,we established a game model to study the strategies of both supervisory and supervised *** obtained results demonstrate that the proposed game model allows for identifying the effectiveness deficiency of the supervisory entity,and the safety and protection altitudes of the supervised *** STAMP-Game model can generate quantitative parameters for supporting the behavior and strategy selections of the supervisory and supervised *** quantitative data obtained can be used to guide the safety improvement,to reduce the costs of safety regulation violation and accident risk.

关键词： Accident analysis STAMP System engineering Gametheory Oil and gas storage and transportation systems

Strengthening in Al-,Mo-or Ti-doped CoCrFeNi high entropy alloys:A parallel comparison

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第35期94卷 264-274页

作者： Xi Li Zhongtao Li Zhenggang Wu shijun zhao Weidong Zhang Hongbin Bei Yanfei Gao College of Materials Science and Engineering&Hunan Province Key Laboratory for Spray Deposition Technology and Application Hunan UniversityChangsha 410082China Department of Mechanical Engineering City University of Hong KongHong KongChina epartment of Materials Science and Engineering Center of Electron Microscopy and State Key Laboratory of Silicon MaterialsZhejiang UniversityHangzhou 310027China Department of Materials Science and Engineering University of TennesseeKnoxvilleTN 37996United States

In the current work,a parallel comparison of the influence of Al,Mo and Ti,on the microstructure and strengthening of the CoCrFeNi alloy was *** achieve this,inconsistencies on variables including the extent of alloying,thermomechanical processing and property-evaluation method were ***,following cold-rolling,annealing of the 4 at.%Al-doped alloys at 800-1000℃ did not result in phase separation;nevertheless,that of the 4 at.%Mo-and Ti-doped alloys led to the respective formation ofσandηphase and,consequently,caused extra strengthening through the Orowan dislocation bypassing *** systematic qualitative analysis and DFT calculations showed that Al and Ti are more effective than Mo in reducing the stacking fault energy(SFE)of the CoCrFeNi alloy,because they can induce more considerable deformation of electronic density,making the gliding of atomic layers *** identical thermomechnical processing,Al-,Mo-,and Ti-doping causes different extent of solid solution strengthening and grain boundary *** causes the most pronounced solid solution strengthening but does not benefit the grain boundary strengthening;in contrast,the effectiveness of grain boundary strengthening is boosted by the doping Al and *** analyses support that Labusch instead of Fleischer mechanism is applicable to explain the differences in solid solution strengthening,and the observed differences in grain boundary strengthening arise from the different tendency of Al,Mo and Ti to reduce the SFE of *** addition,we determined the value of the dimensionless parameter f in the Labusch model for CoCrFeNi-based alloys and observed a close relation between Hall-Petch slope and *** more in-depth studies are needed to provide full and mechanistic understandings,both these findings in fact presents significant values toward designing novel singlephase high-strength CoCrFeNi-based alloys through manipulating the solid solution an

关键词： CoCrFeNi alloy Compositional effect Solid solution strengthening Grain boundary strengthening Precipitation strengthening Stacking fault energy

Design high-entropy carbide ceramics from machine learning

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2022年第1期8卷 36-47页

作者： Jun Zhang Biao Xu Yaoxu Xiong Shihua Ma Zhe Wang Zhenggang Wu shijun zhao Department of Mechanical Engineering City University of Hong KongHong KongChina College of Materials Science and Engineering Hunan UniversityChangshaHunan410082China City University of Hong Kong Shenzhen Research Institute ShenZhen518057China

High-entropy ceramics(HECs)have shown great application potential under demanding conditions,such as high stresses and ***,the immense phase space poses great challenges for the rational design of new high-performance *** this work,we develop machine-learning(ML)models to discover high-entropy ceramic carbides(HECCs).Built upon attributes of HECCs and their constituent precursors,our ML models demonstrate a high prediction accuracy(0.982).Using the well-trained ML models,we evaluate the single-phase probability of 90 HECCs that are not experimentally reported so *** of these predictions are validated by our *** further establish the phase diagrams for non-equiatomic HECCs spanning the whole composition space by which the single-phase regime can be easily *** ML models can predict both equiatomic and non-equiatomic HECs based solely on the chemical descriptors of constituent transition-metal-carbide precursors,which paves the way for the high-throughput design of HECCs with superior properties.

关键词： ceramics properties ceramic