The formability of AA5052/polyethylene/AA5052 sandwich sheets was experimentally studied. Three kinds of AA5052/polyethylene/AA5052 sandwich specimens with different thicknesses of core materials were prepared by the ...The formability of AA5052/polyethylene/AA5052 sandwich sheets was experimentally studied. Three kinds of AA5052/polyethylene/AA5052 sandwich specimens with different thicknesses of core materials were prepared by the hot pressing adhesive method. Then, the uniaxial tensile tests were conducted to investigate the mechanical properties of AA5052/polyethylene/ AA5052 sandwich sheets, and the stretching tests were carried out to investigate the influences of polymer core thickness on the limit dome height of the sandwich sheet. The forming limit curves for three kinds of sandwich sheets were obtained. The experimental results show that the forming limit of the AA5052/polyethylene/AA5052 sandwich sheet is higher than that of the monolithic AA5052 sheet, and it increases with increasing the thickness of polyethylene core.展开更多
Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch. The character- istics of mesophase pitches were examined using polarized light optical microscopy, apparent viscome- try, Fourier...Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch. The character- istics of mesophase pitches were examined using polarized light optical microscopy, apparent viscome- try, Fourier transform infrared spectrometry, IH nuclear magnetic resonance spectrometry, and X-ray diffractometry. The properties of the mesophase pitch were greatly improved because of the eutectic effect. The soluble content increased from 5% to 56%, the mesophase itself increased from 32% to 100%, and the optical texture was changed from a coarse mosaic into a flow domain after the waste polystyrene was added to the ethylene tar pitch. The apparent viscosity showed that the mesophase pitch changed from thixotropic to Newtonian suggesting improved rheological behavior during co-carbonization）The increased number of alkyl groups, which are mainly methylene groups, altered the molecular structure of the mesophase pitch in a way that resulted in the eutectic effect.展开更多
In this paper, the rigid structural thermosensitive polymer （made in lab） of NBS （N-butyl styrene）, N, N-DEAM （diethyl acrylamide） and AM （acrylamide） was prepared. The influence of viscosity for copolymer sol...In this paper, the rigid structural thermosensitive polymer （made in lab） of NBS （N-butyl styrene）, N, N-DEAM （diethyl acrylamide） and AM （acrylamide） was prepared. The influence of viscosity for copolymer solution under different reaction conditions such as temperatures and inorganic salt （monovalent salt and divalent salt） was analyzed. The experiment studies the combination of polymer situation and three different types of surfactants under certain conditions of the room temperature （25℃） and the formation temperature （76℃）. At last, the influence of the surfactant kinds and concentration on the viscosity of the polymer solution are studied. The results show that： The copolymer solution, the apparent viscosity of which decreases with the increasement of temperature, but its viscosity has suddenly increased and thereafter dropped in the transition temperature. So the temperature sensitive effect ofcopolymer is very significantly. When the concentration of inorganic salt and surfactant can be controlled in certain extent, the copolymer solution, the effect increases with the increasement of the concentration, but the viscosity of which decreases with the increasement of shear rate. Shear rate can be controlled in certain extent, shearing stability properties of the copolymer solution are proved.展开更多
Objective: To report the clinical and radiological results of 24 total knee arthroplasty in which all-polyethylene tibial components were used. Methods: Between December 2000 and December 2002, 24 cemented total k...Objective: To report the clinical and radiological results of 24 total knee arthroplasty in which all-polyethylene tibial components were used. Methods: Between December 2000 and December 2002, 24 cemented total knee arthroplasty in 21 patients were performed using all-polyethylene tibial components. The mean age of the 21 patients (9 men and 12 women) at operation was 55 years, ranging 48-61 years. The mean preoperative hospital for special surgery (HSS)score was 40.2 (range, 36-43). The diagnoses were degenerative osteoarthritis in 15 patients, rheumatoid arthritis in 5 and traumatic arthritis in 1. All the operations were performed by the same surgeon group and there were unilateral operations in 18 patients and bilateral operations in 3. Results: Eighteen patients were followed up with a follow-up rate of 85.7%. The mean follow-up is 2.5 years (range, 1-3 years) and mean postoperative HSS scores was 87.5 (range, 83-89). Among them, 18 were excellent, 3 good, 3 poor and none was fair (the results of three lost patients were classified as poor). Of those reviewed, the prosthesis was all in situ and no revision occurred. Radiological assessment of these patients revealed 4 ( 16.67%) tibial components with radiolucent lines (mean width≤2 mm) distributed mainly in zone 1 and zone 4. None of these knees was symptomatic. Conclusions: The result of total knee arthroplasty using all-polyethylene tibial components is encouraging. The operative techniques are similar to those in arthroplasty using metal-backed tibial component.展开更多
基金Project(HIT.NSRIF.2009033) supported by the Scientific Research Foundation of Harbin Institute of Technology,China
文摘The formability of AA5052/polyethylene/AA5052 sandwich sheets was experimentally studied. Three kinds of AA5052/polyethylene/AA5052 sandwich specimens with different thicknesses of core materials were prepared by the hot pressing adhesive method. Then, the uniaxial tensile tests were conducted to investigate the mechanical properties of AA5052/polyethylene/ AA5052 sandwich sheets, and the stretching tests were carried out to investigate the influences of polymer core thickness on the limit dome height of the sandwich sheet. The forming limit curves for three kinds of sandwich sheets were obtained. The experimental results show that the forming limit of the AA5052/polyethylene/AA5052 sandwich sheet is higher than that of the monolithic AA5052 sheet, and it increases with increasing the thickness of polyethylene core.
基金the financial support by the Fundamental Research Funds for the Central Universities (No.2010QNA14)
文摘Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch. The character- istics of mesophase pitches were examined using polarized light optical microscopy, apparent viscome- try, Fourier transform infrared spectrometry, IH nuclear magnetic resonance spectrometry, and X-ray diffractometry. The properties of the mesophase pitch were greatly improved because of the eutectic effect. The soluble content increased from 5% to 56%, the mesophase itself increased from 32% to 100%, and the optical texture was changed from a coarse mosaic into a flow domain after the waste polystyrene was added to the ethylene tar pitch. The apparent viscosity showed that the mesophase pitch changed from thixotropic to Newtonian suggesting improved rheological behavior during co-carbonization）The increased number of alkyl groups, which are mainly methylene groups, altered the molecular structure of the mesophase pitch in a way that resulted in the eutectic effect.
文摘In this paper, the rigid structural thermosensitive polymer （made in lab） of NBS （N-butyl styrene）, N, N-DEAM （diethyl acrylamide） and AM （acrylamide） was prepared. The influence of viscosity for copolymer solution under different reaction conditions such as temperatures and inorganic salt （monovalent salt and divalent salt） was analyzed. The experiment studies the combination of polymer situation and three different types of surfactants under certain conditions of the room temperature （25℃） and the formation temperature （76℃）. At last, the influence of the surfactant kinds and concentration on the viscosity of the polymer solution are studied. The results show that： The copolymer solution, the apparent viscosity of which decreases with the increasement of temperature, but its viscosity has suddenly increased and thereafter dropped in the transition temperature. So the temperature sensitive effect ofcopolymer is very significantly. When the concentration of inorganic salt and surfactant can be controlled in certain extent, the copolymer solution, the effect increases with the increasement of the concentration, but the viscosity of which decreases with the increasement of shear rate. Shear rate can be controlled in certain extent, shearing stability properties of the copolymer solution are proved.
文摘Objective: To report the clinical and radiological results of 24 total knee arthroplasty in which all-polyethylene tibial components were used. Methods: Between December 2000 and December 2002, 24 cemented total knee arthroplasty in 21 patients were performed using all-polyethylene tibial components. The mean age of the 21 patients (9 men and 12 women) at operation was 55 years, ranging 48-61 years. The mean preoperative hospital for special surgery (HSS)score was 40.2 (range, 36-43). The diagnoses were degenerative osteoarthritis in 15 patients, rheumatoid arthritis in 5 and traumatic arthritis in 1. All the operations were performed by the same surgeon group and there were unilateral operations in 18 patients and bilateral operations in 3. Results: Eighteen patients were followed up with a follow-up rate of 85.7%. The mean follow-up is 2.5 years (range, 1-3 years) and mean postoperative HSS scores was 87.5 (range, 83-89). Among them, 18 were excellent, 3 good, 3 poor and none was fair (the results of three lost patients were classified as poor). Of those reviewed, the prosthesis was all in situ and no revision occurred. Radiological assessment of these patients revealed 4 ( 16.67%) tibial components with radiolucent lines (mean width≤2 mm) distributed mainly in zone 1 and zone 4. None of these knees was symptomatic. Conclusions: The result of total knee arthroplasty using all-polyethylene tibial components is encouraging. The operative techniques are similar to those in arthroplasty using metal-backed tibial component.
