The structure of In-1 %Cu and In-5%Cu (mass fraction) alloy melts werestudied at different temperatures above liquidus by using a high-temperature X-ray diffractometerand were compared with that of pure In melt. Exper...The structure of In-1 %Cu and In-5%Cu (mass fraction) alloy melts werestudied at different temperatures above liquidus by using a high-temperature X-ray diffractometerand were compared with that of pure In melt. Experimental results show that with the addition of 1%Cu or 5% Cu, the thermal contraction phenomenon of atom clusters occurs in melts with thetemperature increasing like pure In melt. With the addition of 1% Cu, the thermal contraction ofatom clusters increases and the contraction is not homogeneous in the whole measurement temperaturerange. The sudden change and noticeable contraction can be found in the range of 280-390 ℃. Thetemperature range of the sudden change is lower than that of pure In melt. With the addition of 5%Cu, the thermal contraction of atom clusters decreases and the contraction is not consistent in thewhole measurement temperature range. The anomalous change can be measured at about 600 ℃. At thesame superheating temperature, the nearest interatomic distance r_1 of the melts containing copperis smaller than that of pure In melt, implying that the cluster structure of melts containing copperis more compact.展开更多
The structure of liquid indium was studied at 280, 390, 550, 650, 750?℃, respectively, by using an elevated temperature X ray diffractometer. The diffraction intensity, structure factor, pair distribution function, r...The structure of liquid indium was studied at 280, 390, 550, 650, 750?℃, respectively, by using an elevated temperature X ray diffractometer. The diffraction intensity, structure factor, pair distribution function, radial distribution function, nearest interatomic distance and coordination number were obtained. The results show that the structure of In melt can be approximately described by the random closed packed hard sphere model with hard sphere diameter d =2.86??, packing density η =0.45. The cluster structure of In melt transforms from quasi face centered cubic lattice into random closed packed structure above melting point. It has been found that the nearest interatomic distance r 1 and coordination number N s decrease with increasing temperature from 280?℃ to 750?℃, r 1 decreases from 3.25?? to 3.18?? and N s decreases from 12.771 to 6.648, and thermal contraction phenomenon of atom cluster occurs. Thermal contraction of In melt cluster is not homogeneous in whole measured temperature range. The sudden transformation and the biggest contraction have been found in the range of 390～550?℃.展开更多
This paper presents how the contractions of the main components of a V6 motor with low engine displacement are determined for the cold-start phase under extreme low temperature. Internal combustion engine components h...This paper presents how the contractions of the main components of a V6 motor with low engine displacement are determined for the cold-start phase under extreme low temperature. Internal combustion engine components have complex geometries and to obtain the thermal contractions, in the research, used the method of finite element analysis. The phenomena of thermal contractions are studied for the cold-start situations at extreme low temperature, knowing that the cold-start phase of an internal combustion engine is the main factor that determines moving rotational and translational parts wear life. Checking the proper choice of clearance is particularly important, as the use of inappropriate values of it leads to rapid operation destruction of the engine group components. The results obtained for the thermal clearances of crankshaft bearings are mathematically modeled and the relations can be used for calculating the clearances. The mathematical models are also useful for implementing in different software tools.展开更多
Density functional theory combined with the Gr¨uneisen approximation is used to calculate the thermal properties of single-walled boron nanotubes(BNTs).The specific heat and thermal expansion are investigated.The...Density functional theory combined with the Gr¨uneisen approximation is used to calculate the thermal properties of single-walled boron nanotubes(BNTs).The specific heat and thermal expansion are investigated.The thermal expansion coeffi-cient of the BNT is found to be significantly correlated with tube size and chirality.A remarkable thermal contraction is found at small tube diameters.These results indicate that BNTs would have potential applications in sensors,actuators,and memory materials.展开更多
A series of title compounds as well as their precursors were synthesized by precursor route. Their PXRD patterns were characterized with ZrW2O8 or ZrMo2O8 model by Rietveld method. The thermal contractions of the comp...A series of title compounds as well as their precursors were synthesized by precursor route. Their PXRD patterns were characterized with ZrW2O8 or ZrMo2O8 model by Rietveld method. The thermal contractions of the compounds were determined according to the variable-temperature PXRD data and NTE coefficients were presented. The two-phase mixture of ZrW0.4Mo1.6O8 was also analyzed individually.展开更多
On November 8, 1996. the import contract signing ceremony on the two 660 MW coal-fired generating units of Hanfeng Thermal Power Plant 1st phase was held in the Great Hall of People, Beijing.
基金This work was financially supported by the National Natural Science Foundation of China (No. 50231040)the Natural Science Foundation of Shandong Province, China (No. Z2001F02)
文摘The structure of In-1 %Cu and In-5%Cu (mass fraction) alloy melts werestudied at different temperatures above liquidus by using a high-temperature X-ray diffractometerand were compared with that of pure In melt. Experimental results show that with the addition of 1%Cu or 5% Cu, the thermal contraction phenomenon of atom clusters occurs in melts with thetemperature increasing like pure In melt. With the addition of 1% Cu, the thermal contraction ofatom clusters increases and the contraction is not homogeneous in the whole measurement temperaturerange. The sudden change and noticeable contraction can be found in the range of 280-390 ℃. Thetemperature range of the sudden change is lower than that of pure In melt. With the addition of 5%Cu, the thermal contraction of atom clusters decreases and the contraction is not consistent in thewhole measurement temperature range. The anomalous change can be measured at about 600 ℃. At thesame superheating temperature, the nearest interatomic distance r_1 of the melts containing copperis smaller than that of pure In melt, implying that the cluster structure of melts containing copperis more compact.
文摘The structure of liquid indium was studied at 280, 390, 550, 650, 750?℃, respectively, by using an elevated temperature X ray diffractometer. The diffraction intensity, structure factor, pair distribution function, radial distribution function, nearest interatomic distance and coordination number were obtained. The results show that the structure of In melt can be approximately described by the random closed packed hard sphere model with hard sphere diameter d =2.86??, packing density η =0.45. The cluster structure of In melt transforms from quasi face centered cubic lattice into random closed packed structure above melting point. It has been found that the nearest interatomic distance r 1 and coordination number N s decrease with increasing temperature from 280?℃ to 750?℃, r 1 decreases from 3.25?? to 3.18?? and N s decreases from 12.771 to 6.648, and thermal contraction phenomenon of atom cluster occurs. Thermal contraction of In melt cluster is not homogeneous in whole measured temperature range. The sudden transformation and the biggest contraction have been found in the range of 390～550?℃.
基金funds project PRO-DD (POS-CCE, O.2.2.1., ID 123, SMIS 2637, ctr. No 11/2009) for providing the infrastructure used in this work
文摘This paper presents how the contractions of the main components of a V6 motor with low engine displacement are determined for the cold-start phase under extreme low temperature. Internal combustion engine components have complex geometries and to obtain the thermal contractions, in the research, used the method of finite element analysis. The phenomena of thermal contractions are studied for the cold-start situations at extreme low temperature, knowing that the cold-start phase of an internal combustion engine is the main factor that determines moving rotational and translational parts wear life. Checking the proper choice of clearance is particularly important, as the use of inappropriate values of it leads to rapid operation destruction of the engine group components. The results obtained for the thermal clearances of crankshaft bearings are mathematically modeled and the relations can be used for calculating the clearances. The mathematical models are also useful for implementing in different software tools.
基金the National Basic Research Program of China(973 Program Grant No.2012CB215405)the National Natural Science Foundation of China(Grant No.11374272)City University of Hong Kong(Project No.7008092).
文摘Density functional theory combined with the Gr¨uneisen approximation is used to calculate the thermal properties of single-walled boron nanotubes(BNTs).The specific heat and thermal expansion are investigated.The thermal expansion coeffi-cient of the BNT is found to be significantly correlated with tube size and chirality.A remarkable thermal contraction is found at small tube diameters.These results indicate that BNTs would have potential applications in sensors,actuators,and memory materials.
基金Project (No. 29871006) supported by the National Natural Science Foundation of China.
文摘A series of title compounds as well as their precursors were synthesized by precursor route. Their PXRD patterns were characterized with ZrW2O8 or ZrMo2O8 model by Rietveld method. The thermal contractions of the compounds were determined according to the variable-temperature PXRD data and NTE coefficients were presented. The two-phase mixture of ZrW0.4Mo1.6O8 was also analyzed individually.
文摘On November 8, 1996. the import contract signing ceremony on the two 660 MW coal-fired generating units of Hanfeng Thermal Power Plant 1st phase was held in the Great Hall of People, Beijing.
