Surface morphologies of the films of poly [styrene-b-(ethylene-co-butene)-b-styrene] (SEBS) have been studied by using tapping-mode atomic force microscopy (TM-AFM). The films of block copolymer were prepared bo...Surface morphologies of the films of poly [styrene-b-(ethylene-co-butene)-b-styrene] (SEBS) have been studied by using tapping-mode atomic force microscopy (TM-AFM). The films of block copolymer were prepared both by spin-coating on mica and by solvent-casting on different solution surfaces. For spin-coating samples, the effect of solution concentration, solvent, and annealing temperature are investigated. It is shown that changing the concentration of the solution makes no difference on the morphology of the film of the block copolymer. The microstructures are quite stable during thermal annealing; only the size of the domains changes toward the equilibrium configuration. However, solvent annealing can notably change the microstructures. When different selective solvents are used for film spin-coating, different morphologies can be obtained and explained by the different solubility parameters of the solvents. As expected, significant different morphologies in the top and the bottom surfaces of the casting films were observed. The images of the top surfaces reveal cylinder microdomains, while those of the bottom surfaces were spherical morphologies.展开更多
With the ( k, n )-threshold scheme of secret sharing in the field of information security technology as an application background, the concept of set ( k, n )-exact cover is presented in this paper. It is a modifi...With the ( k, n )-threshold scheme of secret sharing in the field of information security technology as an application background, the concept of set ( k, n )-exact cover is presented in this paper. It is a modification of the original concept of set covering problem. It is also different from the concept of exact cover defined by J.E. Hopcmft. Some properties of (k, n ) -exact cover are investigated; a sufficient condition for a set to be ( k, n ) -exactly coverable is given. It follows that a feasible assignment scheme of a set for the ( k, n) -exact eover is obtained if this set satisfies the sufficient condition.展开更多
Microperoxidase 11(MP 11) was immobilized on the surface of a silanized glass carbon electrode by means of the covalent bond with glutaraldehyde. The measurements of cyclic voltammetry demonstrated that the formal red...Microperoxidase 11(MP 11) was immobilized on the surface of a silanized glass carbon electrode by means of the covalent bond with glutaraldehyde. The measurements of cyclic voltammetry demonstrated that the formal redox potential of immobilized MP 11 was -170 mV, which is significantly more positive than that of MP 11 in a solution or immobilized on the surface of electrodes prepared with other methods. This MP 11 modified electrode showed a good electrocatalytic activity and stability for the reduction of oxygen and hydrogen peroxide.展开更多
Based on the processing experiment and sodium flame test this paper deals with the relationship between processing parameters, structure, and filtration property of melt blown fabric. Through the image analysis of Que...Based on the processing experiment and sodium flame test this paper deals with the relationship between processing parameters, structure, and filtration property of melt blown fabric. Through the image analysis of Questar micro-images in combination with the SEM observation and the measurement of some macrostructure indices, the relationship between the processing parameters and the structure especially the microstructure is emphasized Finally the effect of somestructure factors on filtration properties is discussed theoretically.展开更多
GF14 widely occurs in plant species functioning as a regulatory protein in cell signal transdution, including monoamine synthesis, exocytosis and cell cycle regulation. A partial sequence, 413 bp in length, is cloned ...GF14 widely occurs in plant species functioning as a regulatory protein in cell signal transdution, including monoamine synthesis, exocytosis and cell cycle regulation. A partial sequence, 413 bp in length, is cloned from the bulbs of F. crrihosa by means of RT PCR technique. Sequence alignment with the BLAST program shows that it is highly similar to GF14 gene. A new full length cDNA, 1133 bp, is obtained by RACE techniques. It contains a major open reading frame of 262 amino acids, 5’and 3’ untranslated regions and a long Poly (A) tail. Sequence analysis of deduced GF14 protein from F. crrihosa indicates several conserved motifs of GF14 proteins are also found in sequence of GF14 protein of F. crrihosa.展开更多
Objective To observe the effects of chronic emotional stress on the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and malonialdehyde (MDA) level in female rats’ brain. Methods The rats ...Objective To observe the effects of chronic emotional stress on the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and malonialdehyde (MDA) level in female rats’ brain. Methods The rats were randomly divided into 4 groups: normal control group (group N), emotional stress group (group E), emotional stress + pregnancy group (group E+P) and regularly drinking group (group R). Emotional stress in rats was induced by training rats with empty drinking bottles. Having been finished the stress procedure, the brain was taken out and homogenized. Then the activities of SOD, GSH-Px and MDA level were measured. Results Compared to group N, both the activities of SOD in brain tissues of group E and group E+P were significantly decreased ( P <0.05 and P <0.01, respectively) while the MDA level increased ( P <0.05). However, the extent of changes in group E+P was more obvious than that in E. GSH-Px activities in E+P and E were significantly changed. However, the GSH-Px activity in E+P was decreased ( P <0.05) while the activity in E increased ( P <0.05).Conclusion The chronic emotional stress can reduce the antioxidative system by decreasing the antioxidative enzyme activity and potentiating the lipid peroxidation in the brain. It is also suggested that the combination of emotional stress and pregnancy can augment the oxidative damage in rats’ brain.展开更多
很多朋友在浏览网页的时候会遇到浏览器”卡死”的情况,这多半是因为该网页中有嵌入式的ActiveX插件需要提示安装。为了对付这个问题.市面上有很多相关的“免疫”软件,如NoTroubleMe等,而且Windows XP SP2中也提供了该功能。不过这...很多朋友在浏览网页的时候会遇到浏览器”卡死”的情况,这多半是因为该网页中有嵌入式的ActiveX插件需要提示安装。为了对付这个问题.市面上有很多相关的“免疫”软件,如NoTroubleMe等,而且Windows XP SP2中也提供了该功能。不过这些思路都比较被动,如果遇到新的ActiveX程序,他们就无能为力了。下面笔者来介绍自己的解决方案。展开更多
基金Supported by the National Natural Science Foundation of China (No. 20476025, No. 20236010, No. 20490200) and ShanghaiMunicipal Education Commission of China
摘要Surface morphologies of the films of poly [styrene-b-(ethylene-co-butene)-b-styrene] (SEBS) have been studied by using tapping-mode atomic force microscopy (TM-AFM). The films of block copolymer were prepared both by spin-coating on mica and by solvent-casting on different solution surfaces. For spin-coating samples, the effect of solution concentration, solvent, and annealing temperature are investigated. It is shown that changing the concentration of the solution makes no difference on the morphology of the film of the block copolymer. The microstructures are quite stable during thermal annealing; only the size of the domains changes toward the equilibrium configuration. However, solvent annealing can notably change the microstructures. When different selective solvents are used for film spin-coating, different morphologies can be obtained and explained by the different solubility parameters of the solvents. As expected, significant different morphologies in the top and the bottom surfaces of the casting films were observed. The images of the top surfaces reveal cylinder microdomains, while those of the bottom surfaces were spherical morphologies.
基金Supported by the National Natural Science Foundation of China (No. 60673053 90718011 )
摘要With the ( k, n )-threshold scheme of secret sharing in the field of information security technology as an application background, the concept of set ( k, n )-exact cover is presented in this paper. It is a modification of the original concept of set covering problem. It is also different from the concept of exact cover defined by J.E. Hopcmft. Some properties of (k, n ) -exact cover are investigated; a sufficient condition for a set to be ( k, n ) -exactly coverable is given. It follows that a feasible assignment scheme of a set for the ( k, n) -exact eover is obtained if this set satisfies the sufficient condition.
基金Supported by"973" Project(No. G2 0 0 0 0 2 6 4 0 8) the National Natural Science Foundation of China(No.2 99730 15 ) the Natural Science Foundation of Heilongjiang Province(B2 0 0 0 - 0 6 ) and the Natural Science Foundation of Eduction Comm it-
摘要Microperoxidase 11(MP 11) was immobilized on the surface of a silanized glass carbon electrode by means of the covalent bond with glutaraldehyde. The measurements of cyclic voltammetry demonstrated that the formal redox potential of immobilized MP 11 was -170 mV, which is significantly more positive than that of MP 11 in a solution or immobilized on the surface of electrodes prepared with other methods. This MP 11 modified electrode showed a good electrocatalytic activity and stability for the reduction of oxygen and hydrogen peroxide.
摘要Based on the processing experiment and sodium flame test this paper deals with the relationship between processing parameters, structure, and filtration property of melt blown fabric. Through the image analysis of Questar micro-images in combination with the SEM observation and the measurement of some macrostructure indices, the relationship between the processing parameters and the structure especially the microstructure is emphasized Finally the effect of somestructure factors on filtration properties is discussed theoretically.
摘要GF14 widely occurs in plant species functioning as a regulatory protein in cell signal transdution, including monoamine synthesis, exocytosis and cell cycle regulation. A partial sequence, 413 bp in length, is cloned from the bulbs of F. crrihosa by means of RT PCR technique. Sequence alignment with the BLAST program shows that it is highly similar to GF14 gene. A new full length cDNA, 1133 bp, is obtained by RACE techniques. It contains a major open reading frame of 262 amino acids, 5’and 3’ untranslated regions and a long Poly (A) tail. Sequence analysis of deduced GF14 protein from F. crrihosa indicates several conserved motifs of GF14 proteins are also found in sequence of GF14 protein of F. crrihosa.
摘要Objective To observe the effects of chronic emotional stress on the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and malonialdehyde (MDA) level in female rats’ brain. Methods The rats were randomly divided into 4 groups: normal control group (group N), emotional stress group (group E), emotional stress + pregnancy group (group E+P) and regularly drinking group (group R). Emotional stress in rats was induced by training rats with empty drinking bottles. Having been finished the stress procedure, the brain was taken out and homogenized. Then the activities of SOD, GSH-Px and MDA level were measured. Results Compared to group N, both the activities of SOD in brain tissues of group E and group E+P were significantly decreased ( P <0.05 and P <0.01, respectively) while the MDA level increased ( P <0.05). However, the extent of changes in group E+P was more obvious than that in E. GSH-Px activities in E+P and E were significantly changed. However, the GSH-Px activity in E+P was decreased ( P <0.05) while the activity in E increased ( P <0.05).Conclusion The chronic emotional stress can reduce the antioxidative system by decreasing the antioxidative enzyme activity and potentiating the lipid peroxidation in the brain. It is also suggested that the combination of emotional stress and pregnancy can augment the oxidative damage in rats’ brain.
摘要很多朋友在浏览网页的时候会遇到浏览器”卡死”的情况,这多半是因为该网页中有嵌入式的ActiveX插件需要提示安装。为了对付这个问题.市面上有很多相关的“免疫”软件,如NoTroubleMe等,而且Windows XP SP2中也提供了该功能。不过这些思路都比较被动,如果遇到新的ActiveX程序,他们就无能为力了。下面笔者来介绍自己的解决方案。