Wear-resistant laser-induced thermite reaction Al2O3 ceramic coatings can be fabricated on pure Al and AA7075 aluminum alloy by laser cladding （one-step method） and laser cladding followed by laser re-melting （two-...Wear-resistant laser-induced thermite reaction Al2O3 ceramic coatings can be fabricated on pure Al and AA7075 aluminum alloy by laser cladding （one-step method） and laser cladding followed by laser re-melting （two-step method） using mixed powders CuO-Al-SiO2 in order to improve the wear properties of aluminum and aluminum alloy, respectively. The microstructure of the coatings was characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The wear resistance of the coatings was evaluated under dry sliding wear test condition at room temperature. Owing to the presence of hard α-Al2O3 and γ-Al2O3 phases, the coatings exhibited excellent wear resistance. In addition, the wear resistance of the coatings fabricated by two-step method is superior to that of the coatings fabricated by one-step method.展开更多
Metal matrix composite coating Ni-Fe/SiC was prepared on an iron-based substrate bythermal spraying combined with laser cladding,using SiC particulates as the reinforcing agent.The micro-structures of the coatings for...Metal matrix composite coating Ni-Fe/SiC was prepared on an iron-based substrate bythermal spraying combined with laser cladding,using SiC particulates as the reinforcing agent.The micro-structures of the coatings formed at different thermal spraying and laser cladding conditions were character-ized by means of X-ray diffraction and electron probe microanalysis.The thermal oxidation properties of themixed powders composed of different content of SiC particulates and relevant Ni-based alloy as the balancewere examined using differential scanning calorimetry.The hardness profile of the thermal sprayed and lasercladding coatings was investigated as well.It was found that SiO2particulates were generated and dissolvedand dispersed during the melting and solidification of the laser cladding process,which was ascribed to theoxidation of the dispersed SiC particulates.The micro-hardness depth profile of the target laser claddingcomposite coating was characterized by gradient distribution,which could be related to the gradient distribu-tion of the hard SiC and SiO2particulates in the dendrites and interdendrites of the cladding layer.Both SiCand SiO2particulates contributed to greatly increasing the microhardness and mechanical properties of the ti-tled laser cladding composite coatings.展开更多
On the basis of general situation and new characteristics of tobacco mosaic virus （TMV） in Wuxi tobacco area in 2011, the paper expounded the objec-tive reasons of TMV via systemic investigation, field experiment an...On the basis of general situation and new characteristics of tobacco mosaic virus （TMV） in Wuxi tobacco area in 2011, the paper expounded the objec-tive reasons of TMV via systemic investigation, field experiment and date sorting. Meanwhile, combined with mcteorological conditions and results of systemic inves-tigation, the study especially analyzed meteorological conditions, outbreak and prevalence regularity of TMV and control efficacy of chemical reagents against TMV. The results showed that climatic conditions were the main conditions affecting TMV. There were three occurrence peaks of TMV in 2011, as a result of meteorologi-cal conditions of the months from April to June. The peaks were concerned with a wide range of rainfall about half a month before, low temperature, high humidity and scant sunshine and temperature jump after rain. The results of control effects showed that the chemical reagents could obviously prevent TMV, but once tobacco plants were infected, spraying chemical reagents would not have effective control effect against TMV.展开更多
The purpose of this study was to investigate the effects of copper/low-density polyethylene nanocomposite(nano-Cu/LDPE)on the endometrial angiogenesis in rats,and 100 sexual mature female SD rats were randomly divided...The purpose of this study was to investigate the effects of copper/low-density polyethylene nanocomposite(nano-Cu/LDPE)on the endometrial angiogenesis in rats,and 100 sexual mature female SD rats were randomly divided into five groups:sham-operation groups(SO group,n=20),bulk copper groups(Cu group,n=20),LDPE groups(n=20),nano-Cu/LDPE groups I(n=20)and II(n=20).The levels of angiopoietin-2(Ang-2),its receptor(Tie-2)and CD34 of the rats’endometria in each group were examined by using the S-P method of the immunohistochemistry 30 and 180 days after insertion,respectively.Compared with those in the SO group,the expression of Ang-2 and Tie-2 in all the experimental groups was obviously increased 30 days after insertion,and these parameters in nano-Cu/LDPE groups,except for Ang-2 level in nano-Cu/LDPE group II,were significantly lower in comparison with those in Cu group(P<0.05).On the 180th day after insertion,Ang-2 and Tie-2 levels were still higher in Cu group and LDPE group,but there was no difference of Ang-2 and Tie-2 levels between nano-Cu/LDPE groups and the SO group(P>0.05).Com-pared with those in the SO group,the significant increases in microvessel density(MVD)were observed on the 30th and the 180th day after the insertion of the bulk copper(P<0.05).There was no significant difference in MVD counts before and after the insertion of nano-Cu/LDPE(P>0.05).The results show that Nano-Cu/LDPE have slighter influence on the endometrial angiogenesis than bulk copper.展开更多
基金the Open Fund of the State Key Laboratory of Plastic Forming Simulation and Mould Technology in Huazhong University of Science and Technology(No.05-14)the Open Fund of the State Key Laboratory of Solidification Processing in Northwestern Polytechnic University(No.05-10)
文摘Wear-resistant laser-induced thermite reaction Al2O3 ceramic coatings can be fabricated on pure Al and AA7075 aluminum alloy by laser cladding （one-step method） and laser cladding followed by laser re-melting （two-step method） using mixed powders CuO-Al-SiO2 in order to improve the wear properties of aluminum and aluminum alloy, respectively. The microstructure of the coatings was characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The wear resistance of the coatings was evaluated under dry sliding wear test condition at room temperature. Owing to the presence of hard α-Al2O3 and γ-Al2O3 phases, the coatings exhibited excellent wear resistance. In addition, the wear resistance of the coatings fabricated by two-step method is superior to that of the coatings fabricated by one-step method.
文摘Metal matrix composite coating Ni-Fe/SiC was prepared on an iron-based substrate bythermal spraying combined with laser cladding,using SiC particulates as the reinforcing agent.The micro-structures of the coatings formed at different thermal spraying and laser cladding conditions were character-ized by means of X-ray diffraction and electron probe microanalysis.The thermal oxidation properties of themixed powders composed of different content of SiC particulates and relevant Ni-based alloy as the balancewere examined using differential scanning calorimetry.The hardness profile of the thermal sprayed and lasercladding coatings was investigated as well.It was found that SiO2particulates were generated and dissolvedand dispersed during the melting and solidification of the laser cladding process,which was ascribed to theoxidation of the dispersed SiC particulates.The micro-hardness depth profile of the target laser claddingcomposite coating was characterized by gradient distribution,which could be related to the gradient distribu-tion of the hard SiC and SiO2particulates in the dendrites and interdendrites of the cladding layer.Both SiCand SiO2particulates contributed to greatly increasing the microhardness and mechanical properties of the ti-tled laser cladding composite coatings.
基金Supported by Project of Chongqing Tobacco Monopoly Bureau "Investigation and Research of Harmful Organisms in Tobacco of Chongqing City"
文摘On the basis of general situation and new characteristics of tobacco mosaic virus （TMV） in Wuxi tobacco area in 2011, the paper expounded the objec-tive reasons of TMV via systemic investigation, field experiment and date sorting. Meanwhile, combined with mcteorological conditions and results of systemic inves-tigation, the study especially analyzed meteorological conditions, outbreak and prevalence regularity of TMV and control efficacy of chemical reagents against TMV. The results showed that climatic conditions were the main conditions affecting TMV. There were three occurrence peaks of TMV in 2011, as a result of meteorologi-cal conditions of the months from April to June. The peaks were concerned with a wide range of rainfall about half a month before, low temperature, high humidity and scant sunshine and temperature jump after rain. The results of control effects showed that the chemical reagents could obviously prevent TMV, but once tobacco plants were infected, spraying chemical reagents would not have effective control effect against TMV.
基金support of National“the eleven-fifth”Project of Ministry of Science and Technology of China(NO.2006BAI13B01).
文摘The purpose of this study was to investigate the effects of copper/low-density polyethylene nanocomposite(nano-Cu/LDPE)on the endometrial angiogenesis in rats,and 100 sexual mature female SD rats were randomly divided into five groups:sham-operation groups(SO group,n=20),bulk copper groups(Cu group,n=20),LDPE groups(n=20),nano-Cu/LDPE groups I(n=20)and II(n=20).The levels of angiopoietin-2(Ang-2),its receptor(Tie-2)and CD34 of the rats’endometria in each group were examined by using the S-P method of the immunohistochemistry 30 and 180 days after insertion,respectively.Compared with those in the SO group,the expression of Ang-2 and Tie-2 in all the experimental groups was obviously increased 30 days after insertion,and these parameters in nano-Cu/LDPE groups,except for Ang-2 level in nano-Cu/LDPE group II,were significantly lower in comparison with those in Cu group(P<0.05).On the 180th day after insertion,Ang-2 and Tie-2 levels were still higher in Cu group and LDPE group,but there was no difference of Ang-2 and Tie-2 levels between nano-Cu/LDPE groups and the SO group(P>0.05).Com-pared with those in the SO group,the significant increases in microvessel density(MVD)were observed on the 30th and the 180th day after the insertion of the bulk copper(P<0.05).There was no significant difference in MVD counts before and after the insertion of nano-Cu/LDPE(P>0.05).The results show that Nano-Cu/LDPE have slighter influence on the endometrial angiogenesis than bulk copper.
