The squeeze cast process parameters of AZ80 magnesium alloy were optimized by morphological matrix. Experiments were conducted by varying squeeze pressure, die pre-heat temperature and pressure duration using L9（33）...The squeeze cast process parameters of AZ80 magnesium alloy were optimized by morphological matrix. Experiments were conducted by varying squeeze pressure, die pre-heat temperature and pressure duration using L9（33） orthogonal array of Taguchi method. In Taguchi method, a 3-level orthogonal array was used to determine the signal/noise ratio. Analysis of variance was used to determine the most significant process parameters affecting the mechanical properties. Mechanical properties such as ultimate tensile strength, elongation and hardness of the components were ascertained using multi variable linear regression analysis. Optimal squeeze cast process parameters were obtained.展开更多
A novel rheocasting process, self-inoculation method （SIM）, was developed for the microstructure control of semisolid wrought Mg alloy. This process involves mixing between liquid alloy and particles of solid alloy ...A novel rheocasting process, self-inoculation method （SIM）, was developed for the microstructure control of semisolid wrought Mg alloy. This process involves mixing between liquid alloy and particles of solid alloy （self-inoculants）, subsequently pouring the mixed melt into a special designed multi-stream fluid director. The primary phase with dendritic morphology in the conventionally cast AZ31 alloy has readily transformed into near spherical one in the slurry produced by SIM from melt treatment temperature between 690 ℃ and 710 ℃ and self-inoculants addition of 3%-7%. Achievement of the non-dendritic microstructure at the higher melt treatment temperature requires more self-inoculants addition or decreases in the slope angle of fluid director. Primary phase in the slurry thus produced has attained an ideally globular morphology after isothermal holding at 620 ℃ for 30 s. The increasing holding time leads to decrease of shape factor but the coarsening of particle size. The spheroidization and coarsening evolution process of solid particles during the isothermal holding were analyzed by Lifshitz-Slyozov-Wagner （LSW） theory.展开更多
Improved Resin Transfer Molding (RTM) technology and equipment were established.Void content and morphology of the 3-D braided preform/phenolic composite were investigated using different RTM processes.The results sho...Improved Resin Transfer Molding (RTM) technology and equipment were established.Void content and morphology of the 3-D braided preform/phenolic composite were investigated using different RTM processes.The results showed that void content of the vacuum and compression co-assisted RTM process was the lowest.Void morphologies of the specimen cross-section were analyzed with metallographic microscope.In traditional RTM process,the crack of cross-section was in evidence.In vacuum assisted RTM process,the void shape was divided into three categories:irregular crack,triangle,rotundity and ellipse.The most voids distributed in resin rich areas and were observed as large void based on equivalent diameter.In compression assisted RTM,vacuum and compression co-assisted RTM process,the polygonal voids mostly existed inter tows.Void size was mainly intermediate and small based equivalent diameter separately.展开更多
The relationship between architecture and faith has always been of great wealth. Faith as a way of life and social memory exercises a decisive influence on the shape of the construction environment. Yet this relations...The relationship between architecture and faith has always been of great wealth. Faith as a way of life and social memory exercises a decisive influence on the shape of the construction environment. Yet this relationship is rarely analyzed. On a general level, one reason for this deficiency is probably due to the spread of the ideology of modernity. Given that modernity is implicitly secular, it does not prompt to understand faith in its relationship with other phenomena. It is the same for architecture. We believe on the contrary that the construction environment and the cultural aspect must interact and complement each other. When this is not true or only partially true, this results in user dissatisfaction, and refusal to engage and participate in the process of changing that environment. Many authors have tried to show explicitly the influence of Islamic thought on the social organization and the housing as well as the link between housing and identity, but its implications have not always been understood and transmitted concretely. One thing is certain： the ideological -symbolic-metaphoric sphere is the essence of architecture, as are the program requirements： functionality, distributivity, health of the environment and technology of construction. In this contribution we will address the thorny issue of cultural and religious influences on the choice of the morphology of the habitat and its components, and we will try to highlight the interaction between architecture, faith and culture through analysis of a Mediterranean type ＂House with Patio＂ as a particular architectural style, which has been enriched through the centuries by different cultures. Although the course of this typology in each of these cultures and at different times has not been the same, this has only strengthened the mission and spirit of the ＂Patio＂ until the appropriation of this model by the Arab-Muslim peoples who were able to incorporate the Islamic perception in this space.展开更多
Quaternary chalcogenide Cu2FeSnS4 （CFTS） nanoparticles, as a kind of potential absorber layer material in thin film solar cells （TFSCs）, were successfully synthesized by using a convenient solvothermal method. Alk...Quaternary chalcogenide Cu2FeSnS4 （CFTS） nanoparticles, as a kind of potential absorber layer material in thin film solar cells （TFSCs）, were successfully synthesized by using a convenient solvothermal method. Alkali element K is incorporated into CFTS thin films in order to fiLrther improve the surface morphology and the optical properties of related films. X-ray diffraction （XRD）, Raman spectroscopy and field emission scanning electron microscopy （FESEM） were used to characterize the phase purity, morphology and composition of CFTS particles and thin films. The results show that the particle elemental ratios of Cu/（Fe＋Sn） and Fe/Sn are 1.2 and 0.9, respectively, which are close to the characteristics of stoichiometric CFTS. The band gaps of CFTS films before and after doping K ions are estimated to be 1.44 eV and 1.4 eV with an error of ±0.02 eV.展开更多
基金Project (50975263) supported by the National Natural Science Foundation of ChinaProject (2011DFA50520) supported by International Science Technology Cooperation Program of China
文摘The squeeze cast process parameters of AZ80 magnesium alloy were optimized by morphological matrix. Experiments were conducted by varying squeeze pressure, die pre-heat temperature and pressure duration using L9（33） orthogonal array of Taguchi method. In Taguchi method, a 3-level orthogonal array was used to determine the signal/noise ratio. Analysis of variance was used to determine the most significant process parameters affecting the mechanical properties. Mechanical properties such as ultimate tensile strength, elongation and hardness of the components were ascertained using multi variable linear regression analysis. Optimal squeeze cast process parameters were obtained.
基金Project (2007CB613700) supported by the National Basic Research Program of ChinaProject (50964010) supported by the National Natural Science Foundation of China
文摘A novel rheocasting process, self-inoculation method （SIM）, was developed for the microstructure control of semisolid wrought Mg alloy. This process involves mixing between liquid alloy and particles of solid alloy （self-inoculants）, subsequently pouring the mixed melt into a special designed multi-stream fluid director. The primary phase with dendritic morphology in the conventionally cast AZ31 alloy has readily transformed into near spherical one in the slurry produced by SIM from melt treatment temperature between 690 ℃ and 710 ℃ and self-inoculants addition of 3%-7%. Achievement of the non-dendritic microstructure at the higher melt treatment temperature requires more self-inoculants addition or decreases in the slope angle of fluid director. Primary phase in the slurry thus produced has attained an ideally globular morphology after isothermal holding at 620 ℃ for 30 s. The increasing holding time leads to decrease of shape factor but the coarsening of particle size. The spheroidization and coarsening evolution process of solid particles during the isothermal holding were analyzed by Lifshitz-Slyozov-Wagner （LSW） theory.
基金Tianjin Natural Science Foundation of China(No.06YFJ MJC03100,08JCZDJC24500)
文摘Improved Resin Transfer Molding (RTM) technology and equipment were established.Void content and morphology of the 3-D braided preform/phenolic composite were investigated using different RTM processes.The results showed that void content of the vacuum and compression co-assisted RTM process was the lowest.Void morphologies of the specimen cross-section were analyzed with metallographic microscope.In traditional RTM process,the crack of cross-section was in evidence.In vacuum assisted RTM process,the void shape was divided into three categories:irregular crack,triangle,rotundity and ellipse.The most voids distributed in resin rich areas and were observed as large void based on equivalent diameter.In compression assisted RTM,vacuum and compression co-assisted RTM process,the polygonal voids mostly existed inter tows.Void size was mainly intermediate and small based equivalent diameter separately.
文摘The relationship between architecture and faith has always been of great wealth. Faith as a way of life and social memory exercises a decisive influence on the shape of the construction environment. Yet this relationship is rarely analyzed. On a general level, one reason for this deficiency is probably due to the spread of the ideology of modernity. Given that modernity is implicitly secular, it does not prompt to understand faith in its relationship with other phenomena. It is the same for architecture. We believe on the contrary that the construction environment and the cultural aspect must interact and complement each other. When this is not true or only partially true, this results in user dissatisfaction, and refusal to engage and participate in the process of changing that environment. Many authors have tried to show explicitly the influence of Islamic thought on the social organization and the housing as well as the link between housing and identity, but its implications have not always been understood and transmitted concretely. One thing is certain： the ideological -symbolic-metaphoric sphere is the essence of architecture, as are the program requirements： functionality, distributivity, health of the environment and technology of construction. In this contribution we will address the thorny issue of cultural and religious influences on the choice of the morphology of the habitat and its components, and we will try to highlight the interaction between architecture, faith and culture through analysis of a Mediterranean type ＂House with Patio＂ as a particular architectural style, which has been enriched through the centuries by different cultures. Although the course of this typology in each of these cultures and at different times has not been the same, this has only strengthened the mission and spirit of the ＂Patio＂ until the appropriation of this model by the Arab-Muslim peoples who were able to incorporate the Islamic perception in this space.
基金supported by National Natural Science Foundation of China(No.51674026)the Fundamental Research Funds for the Central Universities in 2015(No.FRF-BD-15-004A)
文摘Quaternary chalcogenide Cu2FeSnS4 （CFTS） nanoparticles, as a kind of potential absorber layer material in thin film solar cells （TFSCs）, were successfully synthesized by using a convenient solvothermal method. Alkali element K is incorporated into CFTS thin films in order to fiLrther improve the surface morphology and the optical properties of related films. X-ray diffraction （XRD）, Raman spectroscopy and field emission scanning electron microscopy （FESEM） were used to characterize the phase purity, morphology and composition of CFTS particles and thin films. The results show that the particle elemental ratios of Cu/（Fe＋Sn） and Fe/Sn are 1.2 and 0.9, respectively, which are close to the characteristics of stoichiometric CFTS. The band gaps of CFTS films before and after doping K ions are estimated to be 1.44 eV and 1.4 eV with an error of ±0.02 eV.
