There are a large number of wooden-plank wall dwellings, a kind of traditional house with regional characteristics, existing in Chongqing area. We chose a typical house in Chongqing as the subject and measured it duri...There are a large number of wooden-plank wall dwellings, a kind of traditional house with regional characteristics, existing in Chongqing area. We chose a typical house in Chongqing as the subject and measured it during summer to research the situation of the indoor thermal comfort of wooden-plank wall dwellings. Based on the particularity of local residents' living habit and the characteristics of the local buildings, we analyzed the data of the field measurement and evaluated the thermal environment with APMV. The results show that the indoor thermal comfort of wooden-plank wall dwellings in summer is improved mainly by natural ventilation.展开更多
This paper proposes a design optimization method for the multi-objective orbit design of earth observation satellites, for which the optimality of orbit performance indices with different units, such as: total coverag...This paper proposes a design optimization method for the multi-objective orbit design of earth observation satellites, for which the optimality of orbit performance indices with different units, such as: total coverage time, the frequency of coverage, average time per coverage and maximum coverage gap, etc. is required simultaneously. By introducing index normalization method to convert performance indices into dimensionless variables within the range of [0, 1], a design optimization method based on the principal component analysis and cluster analysis is proposed, which consists of index normalization method, principal component analysis, multiple-level cluster analysis and weighted evaluation method. The results of orbit optimization for earth observation satellites show that the optimal orbit can be obtained by using the proposed method. The principal component analysis can reduce the total number of indices with a non-independent relationship to save computing time. Similarly, the multiple-level cluster analysis with parallel computing could save computing time.展开更多
Abstract： We mainly studied effects of nucleation parameters （ △Tv,max and △Ts,max ） and superheat on solidification structure of ZG12MnMoV low-alloy steel by integration of CAFE and experimentation. The result s...Abstract： We mainly studied effects of nucleation parameters （ △Tv,max and △Ts,max ） and superheat on solidification structure of ZG12MnMoV low-alloy steel by integration of CAFE and experimentation. The result shows that grain dimension is not only related with nucleation parameters, but also with superheat. The smaller△Tv,max and △Ts,max get, the tinier grain turns. The lab experimentation on optimum parameter is conducted, the mean diameter of grain in lab test specimen is 153.2 lain, and the mean diameter calculated by CAFE model is 151.1 μm. The calculated solidification structure agrees with the experimental result in the main.展开更多
Considering the effect of planet's number on the dynamic characteristics of the planetary gear system, a translationtorsion lumped-parameter model of 2K-H spur planetary gear system was established. Through the an...Considering the effect of planet's number on the dynamic characteristics of the planetary gear system, a translationtorsion lumped-parameter model of 2K-H spur planetary gear system was established. Through the analysis of numerical solution, the results show that 1) When the planet's number is more than 3, the order of the natural frequency will become the same; 2) When the planet's number increases, the natural frequencies of planet mode remain invariant, but when it comes to rotational mode and translational mode, the higher order natural frequencies increase and the lower order natural frequencies decrease; 3) The planet's number has a great impact on the higher order natural frequencies and a little impact on the lower order natural frequencies; and 4) To avoid the resonance, we can appropriately increase or decrease the number of the planet.展开更多
The rotor of a Roots blower is the key component relating to its capability, so the profile design of the rotor in a Roots blower is extremely important. We focused on the modelling and verification for a novel Roots ...The rotor of a Roots blower is the key component relating to its capability, so the profile design of the rotor in a Roots blower is extremely important. We focused on the modelling and verification for a novel Roots blower tooth profile based on the performance analysis. By comparing the area utilization coefficient and the ratio of several traditional rotor profiles, we proposed a new rotor profile. Then, we further accomplished the mathematical modelling of the proposed rotor profile and the computational fluid dynamics(CFD) simulation, and obtained the Roots blower outlet flow monitoring curves. Finally, we verified the characteristics by a physical experiment.展开更多
基金Funded by National Key Technology Research and Development Program of the Ministry of Science and Technology of China During the“12th Five Year Plan”(2013BAJ11B04)Funding Project for fundamental and Frontier Science of the Chongqing Science&Technology Commission(cstc2014jcyj A90024)
文摘There are a large number of wooden-plank wall dwellings, a kind of traditional house with regional characteristics, existing in Chongqing area. We chose a typical house in Chongqing as the subject and measured it during summer to research the situation of the indoor thermal comfort of wooden-plank wall dwellings. Based on the particularity of local residents' living habit and the characteristics of the local buildings, we analyzed the data of the field measurement and evaluated the thermal environment with APMV. The results show that the indoor thermal comfort of wooden-plank wall dwellings in summer is improved mainly by natural ventilation.
基金Funded by 973 Program of Ministry of National Defense of China(Grant No.613237)
文摘This paper proposes a design optimization method for the multi-objective orbit design of earth observation satellites, for which the optimality of orbit performance indices with different units, such as: total coverage time, the frequency of coverage, average time per coverage and maximum coverage gap, etc. is required simultaneously. By introducing index normalization method to convert performance indices into dimensionless variables within the range of [0, 1], a design optimization method based on the principal component analysis and cluster analysis is proposed, which consists of index normalization method, principal component analysis, multiple-level cluster analysis and weighted evaluation method. The results of orbit optimization for earth observation satellites show that the optimal orbit can be obtained by using the proposed method. The principal component analysis can reduce the total number of indices with a non-independent relationship to save computing time. Similarly, the multiple-level cluster analysis with parallel computing could save computing time.
文摘Abstract： We mainly studied effects of nucleation parameters （ △Tv,max and △Ts,max ） and superheat on solidification structure of ZG12MnMoV low-alloy steel by integration of CAFE and experimentation. The result shows that grain dimension is not only related with nucleation parameters, but also with superheat. The smaller△Tv,max and △Ts,max get, the tinier grain turns. The lab experimentation on optimum parameter is conducted, the mean diameter of grain in lab test specimen is 153.2 lain, and the mean diameter calculated by CAFE model is 151.1 μm. The calculated solidification structure agrees with the experimental result in the main.
基金Funded by the Key Research and Development Project in Henan Province(No.142102210067)
文摘Considering the effect of planet's number on the dynamic characteristics of the planetary gear system, a translationtorsion lumped-parameter model of 2K-H spur planetary gear system was established. Through the analysis of numerical solution, the results show that 1) When the planet's number is more than 3, the order of the natural frequency will become the same; 2) When the planet's number increases, the natural frequencies of planet mode remain invariant, but when it comes to rotational mode and translational mode, the higher order natural frequencies increase and the lower order natural frequencies decrease; 3) The planet's number has a great impact on the higher order natural frequencies and a little impact on the lower order natural frequencies; and 4) To avoid the resonance, we can appropriately increase or decrease the number of the planet.
基金Funded by the National Natural Science Foundation of China(No.51375013)Fujian Provincial Research and Development Platform for Industrial Robotic Fundamental Components Technology(No.2014H2004)
文摘The rotor of a Roots blower is the key component relating to its capability, so the profile design of the rotor in a Roots blower is extremely important. We focused on the modelling and verification for a novel Roots blower tooth profile based on the performance analysis. By comparing the area utilization coefficient and the ratio of several traditional rotor profiles, we proposed a new rotor profile. Then, we further accomplished the mathematical modelling of the proposed rotor profile and the computational fluid dynamics(CFD) simulation, and obtained the Roots blower outlet flow monitoring curves. Finally, we verified the characteristics by a physical experiment.
