To obtain dynamic mechanical properties and failure rule of layered backfill under strain rates from10to80s-1,impactloading test on layered backfill specimens(LBS)was conducted by using split Hopkinson pressure bar sy...To obtain dynamic mechanical properties and failure rule of layered backfill under strain rates from10to80s-1,impactloading test on layered backfill specimens(LBS)was conducted by using split Hopkinson pressure bar system.The results indicatethat positive correlation can be found between dynamic compressive strength and strain rate,as well as between strength increasefactor and strain rate.Dynamic compressive strength of LBS gets higher as the arithmetic average cement-sand ratio increases.Compared with static compressive strength,dynamic compressive strength of LBS is enhanced by11%to163%.In addition,theenergy dissipating rate of LBS lies between that of corresponding single specimens,and it decreases as the average cement contentincreases.Deformation of LBS shows obvious discontinuity,deformation degree of lower strength part of LBS is generally higherthan that of higher strength part.A revised brittle fracture criterion based on the Stenerding-Lehnigk criterion is applied to analyzingthe fracture status of LBS,and the average relevant errors of the3groups between the test results and calculation results are4.80%,3.89%and4.66%,respectively.展开更多
Web-based e-commerce applications need a trusted channel,which provides confidential communication,identity authentication and integrity assurance of endpoints,to guarantee the security of electronic transactions.A us...Web-based e-commerce applications need a trusted channel,which provides confidential communication,identity authentication and integrity assurance of endpoints,to guarantee the security of electronic transactions.A user-oriented trusted computing system based on Portable Trusted Module(PTM)is presented.Remote attestation is incorporated into Transport Layer Security(TLS)handshake protocol based on PTM so as to establish a trusted channel between two endpoints in network.This protocol can resist masquerading,trusted path and runtime attacks and propagate the trust in the computing system to the end user effectively.The test results of our proof-of-concept prototype show that our protocol for trusted channel is feasible for deployment in e-commerce applications on the Internet.展开更多
基金Project(2012BAC09B02)supported by the 12th Five-Year Key Programs for Science and Technology Development of ChinaProject(2016zzts444)supported by the Financial Support from the Fundament Research Funds for the Central Universities of Central South University,China
文摘To obtain dynamic mechanical properties and failure rule of layered backfill under strain rates from10to80s-1,impactloading test on layered backfill specimens(LBS)was conducted by using split Hopkinson pressure bar system.The results indicatethat positive correlation can be found between dynamic compressive strength and strain rate,as well as between strength increasefactor and strain rate.Dynamic compressive strength of LBS gets higher as the arithmetic average cement-sand ratio increases.Compared with static compressive strength,dynamic compressive strength of LBS is enhanced by11%to163%.In addition,theenergy dissipating rate of LBS lies between that of corresponding single specimens,and it decreases as the average cement contentincreases.Deformation of LBS shows obvious discontinuity,deformation degree of lower strength part of LBS is generally higherthan that of higher strength part.A revised brittle fracture criterion based on the Stenerding-Lehnigk criterion is applied to analyzingthe fracture status of LBS,and the average relevant errors of the3groups between the test results and calculation results are4.80%,3.89%and4.66%,respectively.
基金partially supported by the Fundamental Research Funds for the Central Universities under Grant No.2011JBM228the Ministry of Education Innovation Research Team under Grant No.IRT201206+1 种基金the Program for New Century Excellent Talents in University under Grant No.NCET-11-0565the Research Fund for the Doctoral Program of Higher Education of China under Grant No.2012000911007
文摘Web-based e-commerce applications need a trusted channel,which provides confidential communication,identity authentication and integrity assurance of endpoints,to guarantee the security of electronic transactions.A user-oriented trusted computing system based on Portable Trusted Module(PTM)is presented.Remote attestation is incorporated into Transport Layer Security(TLS)handshake protocol based on PTM so as to establish a trusted channel between two endpoints in network.This protocol can resist masquerading,trusted path and runtime attacks and propagate the trust in the computing system to the end user effectively.The test results of our proof-of-concept prototype show that our protocol for trusted channel is feasible for deployment in e-commerce applications on the Internet.
