Peroxodiphosphate anion （a powerful oxidant） can be formed in a special water-based cleaning agent through an electrochemical reaction on boron-doped diamond electrodes. This electrochemical reaction was applied dur...Peroxodiphosphate anion （a powerful oxidant） can be formed in a special water-based cleaning agent through an electrochemical reaction on boron-doped diamond electrodes. This electrochemical reaction was applied during the oxidation,decomposition, and removal of organic contaminations on a silicon wafer surface, and it was used as the first step in the diamond electrochemical cleaning technique （DECT）. The cleaning effects of DECT were compared with the RCA cleaning technique, including the silicon surface chemical composition that was observed with X-ray photoelectron spectroscopy and the morphology observed with atomic force microscopy. The measurement results show that the silicon surface cleaned by DECT has slightly less organic residue and lower micro-roughness,so the new technique is more effective than the RCA cleaning technique.展开更多
This articles focuses on analysis of the changing trend relating to crude supply and petroleum products demand inside China, while introducing the preliminary progress resulted from restructuring of China’s refining ...This articles focuses on analysis of the changing trend relating to crude supply and petroleum products demand inside China, while introducing the preliminary progress resulted from restructuring of China’s refining industry and dynamics of competition among Chinese refining enterprises. This article has made a preliminary judgment and analysis on the situation facing China’s refining industry and may serve as a reference to refiners intending to develop refining business inside China.展开更多
The study on options for catalytic cracking of VGO derived from the Kazakhstan-Russian mixed crude was carried out in a small-scale riser FCC unit. The influence of several catalysts and the LCC-A additive for increas...The study on options for catalytic cracking of VGO derived from the Kazakhstan-Russian mixed crude was carried out in a small-scale riser FCC unit. The influence of several catalysts and the LCC-A additive for increasing propylene yield on the distribution and quality of FCC products was analyzed. This article sets forth the possible issues arising from processing the Kazakhstan-Russian mixed crude in FCC unit and the response measures to be adopted.展开更多
This article has suggested that high oil price could loom many years in the future and has analyzed the impact of this trend on the oil product mix and petroleum refining industry in China. This article has also put f...This article has suggested that high oil price could loom many years in the future and has analyzed the impact of this trend on the oil product mix and petroleum refining industry in China. This article has also put forward measures for sharpening the international competitive edge of China’s petroleum refining indus- try to cope with the challenges of high oil price.展开更多
The shear behavior of a single rock joint in limestone specimens,under a constant normal load(CNL),was analyzed in this study.Test specimens with different asperity roughness were prepared and tested.Goodman's mod...The shear behavior of a single rock joint in limestone specimens,under a constant normal load(CNL),was analyzed in this study.Test specimens with different asperity roughness were prepared and tested.Goodman's model of a rock joint's shear behavior,under CNL,was modified to render a better representation of the data obtained.The model's applicability was validated.The proposed model showed better correlation with experimental data.It also,requires fewer variables.The steps to calculate all the necessary variables for the model are discussed.展开更多
The shear behavior of rock joints is important in solving practical problems of rock mechanics. Three group rock joints with different morphologies are made by cement mortar material and a series of CNL(constant norma...The shear behavior of rock joints is important in solving practical problems of rock mechanics. Three group rock joints with different morphologies are made by cement mortar material and a series of CNL(constant normal loading) shear tests are performed. The influences of the applied normal stress and joint morphology to its shear strength are analyzed. According to the experimental results, the peak dilatancy angle of rock joint decreases with increasing normal stress, but increases with increasing roughness. The shear strength increases with the increasing normal stress and the roughness of rock joint. It is observed that the modes of failure of asperities are tensile, pure shear, or a combination of both. It is suggested that the three-dimensional roughness parameters and the tensile strength are the appropriate parameter for describing the shear strength criterion. A new peak shear criterion is proposed which can be used to predict peak shear strength of rock joints. All the used parameters can be easily obtained by performing tests.展开更多
In this paper, concrete with limestone coarse aggregate was studied due to frost action in saline and nonsaline environments. The main focus is to explain the damaging formula of concrete with poor quality of limeston...In this paper, concrete with limestone coarse aggregate was studied due to frost action in saline and nonsaline environments. The main focus is to explain the damaging formula of concrete with poor quality of limestone aggregate in frost actions. All investigated concretes fulfill the recommendations of the European standard EN 206, Concrete--Specification, Performance, Production and Conformity limiting values for composition and properties of concrete （maximum W/C （water/cement） ratio, minimal class of compressive strength, minimal mass of cement and minimal percentage of entrained air）. The damaging formula of the frost resistant concrete is studied through scaling test of concrete during freeze/thaw process, frost resistant test of coarse limestone aggregate and chemical analysis of limestone. Experiments results showed that there is a correlation between CaO/MgO ratio and Al2O3 of limestone and frost resistance of concrete, using chemical composition for determining potential ACR （alkali-carbonate reactivity） will indicate higher risk of damaging effect of concrete.展开更多
Most important problems arising from industrial and technological developments are abundance and harmful effects of post-productive wastes. In most of the developed countries, these effects are avoided by orderly stor...Most important problems arising from industrial and technological developments are abundance and harmful effects of post-productive wastes. In most of the developed countries, these effects are avoided by orderly storing methods. Storing the wastes in random stacks in the site, and their effect on wide areas gives a rise to the risk of ground, air and under water pollution e.g., pollution of the surrounding environments. Therefore, in most engineering branches, effects and nature of harmful wastes are investigated and solution methods are developed. When structures made of concrete are to be demolished. Concrete recycling is an increasingly common method of disposing of the rubble. Concrete debris was once routinely shipped to landfills for disposal, but recycling has a number of benefits that have been made it a more attractive option in this age of greater environmental awareness, more environmental lows, and the desire to keep constant costs down. The purpose of this research is to study the effect of using demolished concrete as a reproducible coarse aggregate in fabricating normal and high strength concrete mixes. The effect of constituent materials in general and the recycled coarse aggregate in particular on the mechanical performance of the produced concrete mixes is investigated. The characteristics of using the by-pass product of cement industry as cementitious material in recycled concrete mixes with a percentage of 50% as a replacement of cement content is investigated too. Test results presented in this research leads to the promising use of crushed demolished concrete along with the by-pass product of cement as waste materials in producing concrete mixes as well as the optimistic results in enhancing the strength properties of plain concrete beside their benefits of the cost savings and reducing environmental impact.展开更多
文摘Peroxodiphosphate anion （a powerful oxidant） can be formed in a special water-based cleaning agent through an electrochemical reaction on boron-doped diamond electrodes. This electrochemical reaction was applied during the oxidation,decomposition, and removal of organic contaminations on a silicon wafer surface, and it was used as the first step in the diamond electrochemical cleaning technique （DECT）. The cleaning effects of DECT were compared with the RCA cleaning technique, including the silicon surface chemical composition that was observed with X-ray photoelectron spectroscopy and the morphology observed with atomic force microscopy. The measurement results show that the silicon surface cleaned by DECT has slightly less organic residue and lower micro-roughness,so the new technique is more effective than the RCA cleaning technique.
文摘This articles focuses on analysis of the changing trend relating to crude supply and petroleum products demand inside China, while introducing the preliminary progress resulted from restructuring of China’s refining industry and dynamics of competition among Chinese refining enterprises. This article has made a preliminary judgment and analysis on the situation facing China’s refining industry and may serve as a reference to refiners intending to develop refining business inside China.
文摘The study on options for catalytic cracking of VGO derived from the Kazakhstan-Russian mixed crude was carried out in a small-scale riser FCC unit. The influence of several catalysts and the LCC-A additive for increasing propylene yield on the distribution and quality of FCC products was analyzed. This article sets forth the possible issues arising from processing the Kazakhstan-Russian mixed crude in FCC unit and the response measures to be adopted.
文摘This article has suggested that high oil price could loom many years in the future and has analyzed the impact of this trend on the oil product mix and petroleum refining industry in China. This article has also put forward measures for sharpening the international competitive edge of China’s petroleum refining indus- try to cope with the challenges of high oil price.
文摘The shear behavior of a single rock joint in limestone specimens,under a constant normal load(CNL),was analyzed in this study.Test specimens with different asperity roughness were prepared and tested.Goodman's model of a rock joint's shear behavior,under CNL,was modified to render a better representation of the data obtained.The model's applicability was validated.The proposed model showed better correlation with experimental data.It also,requires fewer variables.The steps to calculate all the necessary variables for the model are discussed.
基金Project(41130742)supported by the Key Program of National Natural Science Foundation of ChinaProject(2014CB046904)supportedby the National Basic Research Program of China+1 种基金Project(2011CDA119)supported by Natural Science Foundation of Hubei Province,ChinaProject(40972178)supported by the General Program of National Natural Science Foundation of China
文摘The shear behavior of rock joints is important in solving practical problems of rock mechanics. Three group rock joints with different morphologies are made by cement mortar material and a series of CNL(constant normal loading) shear tests are performed. The influences of the applied normal stress and joint morphology to its shear strength are analyzed. According to the experimental results, the peak dilatancy angle of rock joint decreases with increasing normal stress, but increases with increasing roughness. The shear strength increases with the increasing normal stress and the roughness of rock joint. It is observed that the modes of failure of asperities are tensile, pure shear, or a combination of both. It is suggested that the three-dimensional roughness parameters and the tensile strength are the appropriate parameter for describing the shear strength criterion. A new peak shear criterion is proposed which can be used to predict peak shear strength of rock joints. All the used parameters can be easily obtained by performing tests.
文摘In this paper, concrete with limestone coarse aggregate was studied due to frost action in saline and nonsaline environments. The main focus is to explain the damaging formula of concrete with poor quality of limestone aggregate in frost actions. All investigated concretes fulfill the recommendations of the European standard EN 206, Concrete--Specification, Performance, Production and Conformity limiting values for composition and properties of concrete （maximum W/C （water/cement） ratio, minimal class of compressive strength, minimal mass of cement and minimal percentage of entrained air）. The damaging formula of the frost resistant concrete is studied through scaling test of concrete during freeze/thaw process, frost resistant test of coarse limestone aggregate and chemical analysis of limestone. Experiments results showed that there is a correlation between CaO/MgO ratio and Al2O3 of limestone and frost resistance of concrete, using chemical composition for determining potential ACR （alkali-carbonate reactivity） will indicate higher risk of damaging effect of concrete.
文摘Most important problems arising from industrial and technological developments are abundance and harmful effects of post-productive wastes. In most of the developed countries, these effects are avoided by orderly storing methods. Storing the wastes in random stacks in the site, and their effect on wide areas gives a rise to the risk of ground, air and under water pollution e.g., pollution of the surrounding environments. Therefore, in most engineering branches, effects and nature of harmful wastes are investigated and solution methods are developed. When structures made of concrete are to be demolished. Concrete recycling is an increasingly common method of disposing of the rubble. Concrete debris was once routinely shipped to landfills for disposal, but recycling has a number of benefits that have been made it a more attractive option in this age of greater environmental awareness, more environmental lows, and the desire to keep constant costs down. The purpose of this research is to study the effect of using demolished concrete as a reproducible coarse aggregate in fabricating normal and high strength concrete mixes. The effect of constituent materials in general and the recycled coarse aggregate in particular on the mechanical performance of the produced concrete mixes is investigated. The characteristics of using the by-pass product of cement industry as cementitious material in recycled concrete mixes with a percentage of 50% as a replacement of cement content is investigated too. Test results presented in this research leads to the promising use of crushed demolished concrete along with the by-pass product of cement as waste materials in producing concrete mixes as well as the optimistic results in enhancing the strength properties of plain concrete beside their benefits of the cost savings and reducing environmental impact.
