Bumps in coal mines have been recognized as a major hazard for many years. These sudden and violent failures around mine openings have compromised safety, ventilation and access to mine workings.Previous studies showe...Bumps in coal mines have been recognized as a major hazard for many years. These sudden and violent failures around mine openings have compromised safety, ventilation and access to mine workings.Previous studies showed that the violence of coal specimen failure depends on both the interface friction and width-to-height（W/H） ratio of coal specimen. The mode of failure for a uniaxially loaded coal specimen or a coal pillar is a combination of both shear failure along the interface and compressive failure in the coal. The shear failure along the interface triggered the compressive failure in coal. The compressive failure of a coal specimen or a coal pillar can be controlled by changing its W/H ratio. As the W/H ratio increases, the ultimate strength increases. Hence, with a proper combination of interface friction and the W/H ratio of pillar or coal specimen, the mode of failure will change from sudden violent failure which is brittle failure to non-violent failure which is ductile failure. The main objective of this paper is to determine at what W/H ratio and interface friction the mode of failure changes from violent to non-violent. In this research, coal specimens of W/H ratio ranging from 1 to 10 were uniaxially tested under two interface frictions of 0.1 and 0.25, and the results are presented and discussed.展开更多
The presence of chloride ions is the critical factor of passivity breakdown of the protective film and eventually leads to localized corrosion. However, the mechanism and the role of chlorides in these processes are s...The presence of chloride ions is the critical factor of passivity breakdown of the protective film and eventually leads to localized corrosion. However, the mechanism and the role of chlorides in these processes are still controversial. Hematite and chromia are generally believed to be the major components of outer and inner oxide layers on stainless steels. In the present paper, a comparative study of Cl ingress into pristine and defective α-Fe_(2)O_(3)(0001) surface, α-Cr_(2)O_(3)(0001) surface, along with their interface, was conducted using density functional theory. Vacancy formation energy calculation confirms good stability of α-Cr_(2)O_(3)and high reactive activity of the interface region. Cl inserts into an O vacancy is energetically more favorable than Fe vacancy and interstitial site, demonstrating Cl-induced degradation complies with the ion exchange model. Transition state search for Cl diffusion through O vacancies shows α-Cr_(2)O_(3)is more protective than α-Fe_(2)O_(3), while the interface region is the weak point of the duplex passive film.展开更多
Explosion welding was carried out on the basis of vacuum hot melt W/CuCrZr composite plate.Metallurgical microscope,scanning electron microscope and energy dispersive X-ray spectroscope were used to observe the micros...Explosion welding was carried out on the basis of vacuum hot melt W/CuCrZr composite plate.Metallurgical microscope,scanning electron microscope and energy dispersive X-ray spectroscope were used to observe the microscopic morphology of the bonding interface.At the same time,combined with finite element calculations,the evolution mechanism of the interface of the hot melt explosion welded W/CuCrZr composite plate was explored.The results show that the interface bonding of the hot melt explosion welded W/CuCrZr composite plate is good and there is a cross-melting zone with 3–8μm in thickness,but cracks are developed on the W side.The numerical simulation reproduces the changes of pressure,stress,strain and internal energy at the bonding interface in the process of hot melt explosion welding.The location of the crack generated in the experiment coincides with the high stress position calculated by numerical simulation.The high pressure and high temperature near the hot melt explosion welding interface further promote the bonding of the interface.展开更多
The microhardness and modulus changes of the interface between U-0.75Ti alloy and TiC before andafter heat treatment were studied by SEM and Nano Indenter II, and the results show that the hardness and modulusof the i...The microhardness and modulus changes of the interface between U-0.75Ti alloy and TiC before andafter heat treatment were studied by SEM and Nano Indenter II, and the results show that the hardness and modulusof the interface are greatly increased after 820℃, 2 h water quenching and 450℃, 6 h aging. This result probablycomes from much more U2Ti and U6Ni precipitates along the interface.展开更多
The transfer of Sr^2+ and Ba^2+ ion,facilitated by 18-crown-6 present in the aqueous phase,and of succinylcholine ion at w/nb interface were investigated by semi-differeniial cyclic voltammetry.A good polarographic cu...The transfer of Sr^2+ and Ba^2+ ion,facilitated by 18-crown-6 present in the aqueous phase,and of succinylcholine ion at w/nb interface were investigated by semi-differeniial cyclic voltammetry.A good polarographic curve of succinylcholine ion dissolved in water was obtained in the system of 0.01 mol/l LiCl(w)-0.01mol/l TBATPB(nb).The peak current is directly proportional to the concentration of SC^2+ ion.It can be used for the determination of SC and the detection limit is 1.05×10^-5mol/l,The apparent D^m and D^mb have been estimated.The transfer of Sr^2+ and of Ba^2+ at the interface are facilitated by 18-Crown-6 present in the aqueous phase and the peak current is directly proportional to the concentration of 18-Crown-6 in water.This method can be used for the determination of the complexing agent and for the stability constant of the complex formed in the aqueous phase.All the experimental results are in keeping with the theoretical.展开更多
With increasing usage of a web services today, user required to consecrate reasoning energy to learning the complexities of the interface as opposed to the content. Interface complexity measures the degree of complexi...With increasing usage of a web services today, user required to consecrate reasoning energy to learning the complexities of the interface as opposed to the content. Interface complexity measures the degree of complexity encountered between the user and digital medium like website. This paper presents a New Interface Complexity (NIC) Metric, which partially based on existing schema metrics to weigh human insight of recent service interface;taking into account elements and attributes of XML documents implemented in?World Wide Web Consortium (W3C) XML Schema (WXS) to reduce the structure affecting the effort for comprehending schema documents. The NIC metric is able to draw conclusions about the perceived qualities: interoperability, extensibility and flexibility. It was discovered that there are significant correlations between NIC metric and existing measures. Automating, this practice would be beneficial to developers and designers, as it would help to provide useful feedback in software project design to check the quality of documents for easy maintenance and properly used of XML data for distributed applications.展开更多
This paper describes the invesligation of the transfer behaviour of the alkaline earth-metal cations across the water/nitrobenzene interface facilitated by josamycin in the nitrobenzene phase using semi-differential c...This paper describes the invesligation of the transfer behaviour of the alkaline earth-metal cations across the water/nitrobenzene interface facilitated by josamycin in the nitrobenzene phase using semi-differential cyclic voltammetry .The peak height is directly proportional to the concentration of josaycin (nb) and to the potential scan rate.The complexes formed from alkaline earth-metal ions and josamycin at the w/nb interface are ML2^2+ ion.展开更多
The stability, bonding, work of adhesion and electronic structure of the U/W interface with and without Ti were investigated by first principles to explore the me- chanical properties of W particles enhanced U-Ti allo...The stability, bonding, work of adhesion and electronic structure of the U/W interface with and without Ti were investigated by first principles to explore the me- chanical properties of W particles enhanced U-Ti alloy matrix composite as a construction material. The calculated results indicate that the preferable orientation of the U/W interfacial structure is （001）U/（110）w crystallographic plane, Ti atoms originating from U slab are prone to diffuse into W slab through the interface, and additional Ti in U matrix is the stronger adhesion to W, with an ideal work of adhesion of 6.93 J.m-2 for U-Ti/W interface, relative to the value of 6.72 J.m-2 for clean U/W interface. The stronger adhesion performance is due to the increase in valence electron hybridization for U-Ti/W compared with U/W interface, as evidenced by the characteristic of the local density of states for the interfacial atoms.展开更多
基金sponsored by Coal and Energy Research Bureau and CDC-NIOSH under Grant No.R01OH009532
文摘Bumps in coal mines have been recognized as a major hazard for many years. These sudden and violent failures around mine openings have compromised safety, ventilation and access to mine workings.Previous studies showed that the violence of coal specimen failure depends on both the interface friction and width-to-height（W/H） ratio of coal specimen. The mode of failure for a uniaxially loaded coal specimen or a coal pillar is a combination of both shear failure along the interface and compressive failure in the coal. The shear failure along the interface triggered the compressive failure in coal. The compressive failure of a coal specimen or a coal pillar can be controlled by changing its W/H ratio. As the W/H ratio increases, the ultimate strength increases. Hence, with a proper combination of interface friction and the W/H ratio of pillar or coal specimen, the mode of failure will change from sudden violent failure which is brittle failure to non-violent failure which is ductile failure. The main objective of this paper is to determine at what W/H ratio and interface friction the mode of failure changes from violent to non-violent. In this research, coal specimens of W/H ratio ranging from 1 to 10 were uniaxially tested under two interface frictions of 0.1 and 0.25, and the results are presented and discussed.
基金supported by the Key Research Program of Frontier Sciences,CAS(No.QYZDY-SSW-JSC012)the Aeronautical Science Foundation of China(No.20200038092002)。
文摘The presence of chloride ions is the critical factor of passivity breakdown of the protective film and eventually leads to localized corrosion. However, the mechanism and the role of chlorides in these processes are still controversial. Hematite and chromia are generally believed to be the major components of outer and inner oxide layers on stainless steels. In the present paper, a comparative study of Cl ingress into pristine and defective α-Fe_(2)O_(3)(0001) surface, α-Cr_(2)O_(3)(0001) surface, along with their interface, was conducted using density functional theory. Vacancy formation energy calculation confirms good stability of α-Cr_(2)O_(3)and high reactive activity of the interface region. Cl inserts into an O vacancy is energetically more favorable than Fe vacancy and interstitial site, demonstrating Cl-induced degradation complies with the ion exchange model. Transition state search for Cl diffusion through O vacancies shows α-Cr_(2)O_(3)is more protective than α-Fe_(2)O_(3), while the interface region is the weak point of the duplex passive film.
基金National Natural Science Foundation of China(12072363,12272374,12372373)Special Fund for Fundamental Research of the Central Universities(WK2480000008,WK2480000007,WK2320000049)Anhui Provincial Science and Technology Major Project(202003A05020035)。
文摘Explosion welding was carried out on the basis of vacuum hot melt W/CuCrZr composite plate.Metallurgical microscope,scanning electron microscope and energy dispersive X-ray spectroscope were used to observe the microscopic morphology of the bonding interface.At the same time,combined with finite element calculations,the evolution mechanism of the interface of the hot melt explosion welded W/CuCrZr composite plate was explored.The results show that the interface bonding of the hot melt explosion welded W/CuCrZr composite plate is good and there is a cross-melting zone with 3–8μm in thickness,but cracks are developed on the W side.The numerical simulation reproduces the changes of pressure,stress,strain and internal energy at the bonding interface in the process of hot melt explosion welding.The location of the crack generated in the experiment coincides with the high stress position calculated by numerical simulation.The high pressure and high temperature near the hot melt explosion welding interface further promote the bonding of the interface.
文摘The microhardness and modulus changes of the interface between U-0.75Ti alloy and TiC before andafter heat treatment were studied by SEM and Nano Indenter II, and the results show that the hardness and modulusof the interface are greatly increased after 820℃, 2 h water quenching and 450℃, 6 h aging. This result probablycomes from much more U2Ti and U6Ni precipitates along the interface.
文摘The transfer of Sr^2+ and Ba^2+ ion,facilitated by 18-crown-6 present in the aqueous phase,and of succinylcholine ion at w/nb interface were investigated by semi-differeniial cyclic voltammetry.A good polarographic curve of succinylcholine ion dissolved in water was obtained in the system of 0.01 mol/l LiCl(w)-0.01mol/l TBATPB(nb).The peak current is directly proportional to the concentration of SC^2+ ion.It can be used for the determination of SC and the detection limit is 1.05×10^-5mol/l,The apparent D^m and D^mb have been estimated.The transfer of Sr^2+ and of Ba^2+ at the interface are facilitated by 18-Crown-6 present in the aqueous phase and the peak current is directly proportional to the concentration of 18-Crown-6 in water.This method can be used for the determination of the complexing agent and for the stability constant of the complex formed in the aqueous phase.All the experimental results are in keeping with the theoretical.
文摘With increasing usage of a web services today, user required to consecrate reasoning energy to learning the complexities of the interface as opposed to the content. Interface complexity measures the degree of complexity encountered between the user and digital medium like website. This paper presents a New Interface Complexity (NIC) Metric, which partially based on existing schema metrics to weigh human insight of recent service interface;taking into account elements and attributes of XML documents implemented in?World Wide Web Consortium (W3C) XML Schema (WXS) to reduce the structure affecting the effort for comprehending schema documents. The NIC metric is able to draw conclusions about the perceived qualities: interoperability, extensibility and flexibility. It was discovered that there are significant correlations between NIC metric and existing measures. Automating, this practice would be beneficial to developers and designers, as it would help to provide useful feedback in software project design to check the quality of documents for easy maintenance and properly used of XML data for distributed applications.
文摘This paper describes the invesligation of the transfer behaviour of the alkaline earth-metal cations across the water/nitrobenzene interface facilitated by josamycin in the nitrobenzene phase using semi-differential cyclic voltammetry .The peak height is directly proportional to the concentration of josaycin (nb) and to the potential scan rate.The complexes formed from alkaline earth-metal ions and josamycin at the w/nb interface are ML2^2+ ion.
基金financially supported by the National Natural Science Foundation of China(Nos.51074103 and 51104098)shanghai university scientific selection and cultivation for outstanding young teachers in special fund and Innovation Program of Shanghai University (SDCX2012011)
文摘The stability, bonding, work of adhesion and electronic structure of the U/W interface with and without Ti were investigated by first principles to explore the me- chanical properties of W particles enhanced U-Ti alloy matrix composite as a construction material. The calculated results indicate that the preferable orientation of the U/W interfacial structure is （001）U/（110）w crystallographic plane, Ti atoms originating from U slab are prone to diffuse into W slab through the interface, and additional Ti in U matrix is the stronger adhesion to W, with an ideal work of adhesion of 6.93 J.m-2 for U-Ti/W interface, relative to the value of 6.72 J.m-2 for clean U/W interface. The stronger adhesion performance is due to the increase in valence electron hybridization for U-Ti/W compared with U/W interface, as evidenced by the characteristic of the local density of states for the interfacial atoms.
