For the purpose of improving the defects of the conventional friction welding method, the new friction welding technology has been examined. That is, the aim of the study is producing the joint of dissimilar materials...For the purpose of improving the defects of the conventional friction welding method, the new friction welding technology has been examined. That is, the aim of the study is producing the joint of dissimilar materials evaluated to be difficult for friction welding and non-round shape joints. In this process, after the intermediate material generates the independent friction heat on every side of the specimens, it is removed instantaneously and upset process begins to weld the specimens for a joint. In this study, similar joint of A2017 aluminum alloy and one of S45C steel were examined. On the other hand, thermal elastic-plastic stress analysis by the finite element method was carried out using ANSYS mechanical.展开更多
Purpose: To investigate the periapical tissue response after root end filling with intermediate restorative material (IRM) and filling of the root-end resection bone defects with autogenous bone or a bone graft substi...Purpose: To investigate the periapical tissue response after root end filling with intermediate restorative material (IRM) and filling of the root-end resection bone defects with autogenous bone or a bone graft substitute in comparison to empty controls. Materials and Methods: Vital roots of the second, third and fourth mandibular premolars in six healthy mongrel dogs were apectomized. The root canals were prepared and sealed with IRM following a standardized surgical procedure. The resection bone defects were either filled with autogenous bone (PB) or one of the bone graft substitutes;CERAMENTTM|BONE VOID FILLER, ChronOS?, TigranTM PTG, Easygraft? CLASSIC or left empty. After 120 days the animals were sacrificed and the specimens were analyzed radiologically and histologically. Kruskal-Wallis and Mann-Whitney tests were performed for statistical evaluation. Results: 34 sections were analyzed histologically. The evaluation revealed a variation in the outcome amongst the tested options, regarding reestablishment of the periapical bone healing and inflammatory infiltration in the sections. According to the tested variables, there was no statistical significant difference between the materials when comparing all groups as a whole. When comparing individual materials to each other there was statistical differences among some of the tested materials. Conclusion: The healing outcome after periapical surgery of a five-wall resection defect could not be increased by infill with autogenous bone or bone graft substitutes. The most important factor for the healing outcome in periapical surgery is the quality of the root-end sealing. The healing outcome after some of the tested bone substitutes, might be improved by longer healing time.展开更多
Electrical resistance, thermal expansion, lattice constants of the intermediate valence materials, α-Ce and CeBe 13, were measured at high pressure. It is found that the Grüneisen parameters of Kondo temperat...Electrical resistance, thermal expansion, lattice constants of the intermediate valence materials, α-Ce and CeBe 13, were measured at high pressure. It is found that the Grüneisen parameters of Kondo temperature T K are 13 and 42 for α-Ce and CeBe 13, respectively, and it decreases with increasing pressure. The magnetoresistance of α-Ce shows H2 dependence and its coefficient increases with pressure below 1 GPa, but becomes nearly constant above 1 GPa. The results indicate that the intermediate valence states are enhanced at high pressure indicating the enhancement of hybridization between the 4f electron and conduction band.展开更多
The electronic structure characters are calculated for the Zn1-∞MxO alloys with some Zn atoms in ZnO substituted by 3d transition-metal atoms （M）, in order to find out which of these alloys could provide an interme...The electronic structure characters are calculated for the Zn1-∞MxO alloys with some Zn atoms in ZnO substituted by 3d transition-metal atoms （M）, in order to find out which of these alloys could provide an intermediate band material used for fabricating high efficiency solar cell. Especially, among of these alloys, the electronic structure character and optical performance of Zn1-xCr∞ 0 alloys clearly show an intermediate band filled partially and isolated from the VB and the CB in energy band structure of ZnO host, and the intermediate band characters can be preserved with increasing Cr concentrations no more than 8.33% in Zn1-xCrxO alloys, at the same time, the ratio 0.52 of Eg^FC to EVE in Zn1-xCrxO, （x = 4.16%） alloy is closest to the optimal ratio of 0,57. Besides, compared to the ZnO, the optical absorption does indicate a great improved absorption below the calculated band gap of the ZnO and an enhancement of the optical absorption in the whole solar spectral energy range.展开更多
In developing the new friction welding technology, the thermal elastic-plastic stress analysis by the finite element method was carried out to seek the suitable welding conditions such as the friction pressure, the fr...In developing the new friction welding technology, the thermal elastic-plastic stress analysis by the finite element method was carried out to seek the suitable welding conditions such as the friction pressure, the friction speed and the upset pressure. The results obtained are as follows： Heat transfer to the specimens and the intermediate material during friction process was made clear; The operational conditions such as the rotation number of the intermediate material and the friction pressure to reach the liquidus in the interface could be estimated; Further, as the overhang length near the interface is well related to the joint efficiency, we tried to obtain the operational conditions by numerical analysis to acquire a certain length of the overhang length near the interface.展开更多
文摘For the purpose of improving the defects of the conventional friction welding method, the new friction welding technology has been examined. That is, the aim of the study is producing the joint of dissimilar materials evaluated to be difficult for friction welding and non-round shape joints. In this process, after the intermediate material generates the independent friction heat on every side of the specimens, it is removed instantaneously and upset process begins to weld the specimens for a joint. In this study, similar joint of A2017 aluminum alloy and one of S45C steel were examined. On the other hand, thermal elastic-plastic stress analysis by the finite element method was carried out using ANSYS mechanical.
文摘Purpose: To investigate the periapical tissue response after root end filling with intermediate restorative material (IRM) and filling of the root-end resection bone defects with autogenous bone or a bone graft substitute in comparison to empty controls. Materials and Methods: Vital roots of the second, third and fourth mandibular premolars in six healthy mongrel dogs were apectomized. The root canals were prepared and sealed with IRM following a standardized surgical procedure. The resection bone defects were either filled with autogenous bone (PB) or one of the bone graft substitutes;CERAMENTTM|BONE VOID FILLER, ChronOS?, TigranTM PTG, Easygraft? CLASSIC or left empty. After 120 days the animals were sacrificed and the specimens were analyzed radiologically and histologically. Kruskal-Wallis and Mann-Whitney tests were performed for statistical evaluation. Results: 34 sections were analyzed histologically. The evaluation revealed a variation in the outcome amongst the tested options, regarding reestablishment of the periapical bone healing and inflammatory infiltration in the sections. According to the tested variables, there was no statistical significant difference between the materials when comparing all groups as a whole. When comparing individual materials to each other there was statistical differences among some of the tested materials. Conclusion: The healing outcome after periapical surgery of a five-wall resection defect could not be increased by infill with autogenous bone or bone graft substitutes. The most important factor for the healing outcome in periapical surgery is the quality of the root-end sealing. The healing outcome after some of the tested bone substitutes, might be improved by longer healing time.
文摘Electrical resistance, thermal expansion, lattice constants of the intermediate valence materials, α-Ce and CeBe 13, were measured at high pressure. It is found that the Grüneisen parameters of Kondo temperature T K are 13 and 42 for α-Ce and CeBe 13, respectively, and it decreases with increasing pressure. The magnetoresistance of α-Ce shows H2 dependence and its coefficient increases with pressure below 1 GPa, but becomes nearly constant above 1 GPa. The results indicate that the intermediate valence states are enhanced at high pressure indicating the enhancement of hybridization between the 4f electron and conduction band.
基金Supported by the State Key Program for Basic Research of China under Grant No.2006CB921803Project of High Technology Research&Development of China(Project No.2007AA03Z404)+1 种基金National Natural Science Foundation of China under Grant Nos.61274058,60990312,and 61025020Natural Science Foundation of Anhui Province under Grant No.1208085QF116
文摘The electronic structure characters are calculated for the Zn1-∞MxO alloys with some Zn atoms in ZnO substituted by 3d transition-metal atoms （M）, in order to find out which of these alloys could provide an intermediate band material used for fabricating high efficiency solar cell. Especially, among of these alloys, the electronic structure character and optical performance of Zn1-xCr∞ 0 alloys clearly show an intermediate band filled partially and isolated from the VB and the CB in energy band structure of ZnO host, and the intermediate band characters can be preserved with increasing Cr concentrations no more than 8.33% in Zn1-xCrxO alloys, at the same time, the ratio 0.52 of Eg^FC to EVE in Zn1-xCrxO, （x = 4.16%） alloy is closest to the optimal ratio of 0,57. Besides, compared to the ZnO, the optical absorption does indicate a great improved absorption below the calculated band gap of the ZnO and an enhancement of the optical absorption in the whole solar spectral energy range.
文摘In developing the new friction welding technology, the thermal elastic-plastic stress analysis by the finite element method was carried out to seek the suitable welding conditions such as the friction pressure, the friction speed and the upset pressure. The results obtained are as follows： Heat transfer to the specimens and the intermediate material during friction process was made clear; The operational conditions such as the rotation number of the intermediate material and the friction pressure to reach the liquidus in the interface could be estimated; Further, as the overhang length near the interface is well related to the joint efficiency, we tried to obtain the operational conditions by numerical analysis to acquire a certain length of the overhang length near the interface.
