The semiempirical calculations were performed to discuss the effects of different substituents on the optical properties of a series of substituted benzonitriles and their corresponding oligomers. The substituents loc...The semiempirical calculations were performed to discuss the effects of different substituents on the optical properties of a series of substituted benzonitriles and their corresponding oligomers. The substituents located in para, meta and ortho-position of the benzenoid ring involve a large range of delta-pi electron-donor-acceptor capability. Theoretical analysis shows that the optical property is affected by the steric and electronic characteristics of the substituents on the benzenoid ring, moreover, the third-order polarizability regularly varies with the polymerization degrees.展开更多
Nanocrystalline powders in the Ni-Ti and Ni-Cr systems were prepared by mechanical alloying (MA) of elemental crystalline powders in an inert atmosphere. The microstructure of the mechanically alloyed powders were cha...Nanocrystalline powders in the Ni-Ti and Ni-Cr systems were prepared by mechanical alloying (MA) of elemental crystalline powders in an inert atmosphere. The microstructure of the mechanically alloyed powders were characterized by XRD and TEM. The ball-milling process results in a drastic decrease of the crystallite size to the nanometer scale. X-ray diffraction analysis reveals that in the Ni-Cr system, no diffraction peaks from NiCr compound were observed even after 20 h of bail milling; while the lattice parameter of Ni increased with the milling time. In the Ni-Ti system, amorphous alloy was formed. Crystalline intermetallic compounds were obtained by post heat treatment of the amorphous alloy. The crystallization temperature of the amorphous NiTi alloy was obtained by DSC measurement.展开更多
High purity hot hydrogen charging at high temperature was used to investigate the hydrogen embrittlement (HE) of JBK-75 alloys with different contents of P and Si(Mn). The results indicated that by lowering P content,...High purity hot hydrogen charging at high temperature was used to investigate the hydrogen embrittlement (HE) of JBK-75 alloys with different contents of P and Si(Mn). The results indicated that by lowering P content, the size and distribution of gamma' precipitate became more homogeneous and the precipitation of stable phase eta was retarded, thus the hydrogen resistant properties of the alloy was obviously improved; however, when Si(Mn) content was lowered together with P, though the size and density of gamma' were also homogeneous and no eta phase was observed, formation of some micro twin around grain boundaries was found to be detrimental to the hydrogen performance of the alloy, and hydrogen induced loss of area reduction was very high. Therefore, to improve the hydrogen resistant properties of the alloy, P content should be lowered while certain amount of Si(Mn) should be kept.展开更多
The quantitative structural parameters and activity relationship of pyrrolobenzothiazepin-ones and pyrrolobenzoxazepinones' inhibitory activities on HIV-1 reverse transcriptase (RT) was studied. A good relationshi...The quantitative structural parameters and activity relationship of pyrrolobenzothiazepin-ones and pyrrolobenzoxazepinones' inhibitory activities on HIV-1 reverse transcriptase (RT) was studied. A good relationship has been built.展开更多
文摘The semiempirical calculations were performed to discuss the effects of different substituents on the optical properties of a series of substituted benzonitriles and their corresponding oligomers. The substituents located in para, meta and ortho-position of the benzenoid ring involve a large range of delta-pi electron-donor-acceptor capability. Theoretical analysis shows that the optical property is affected by the steric and electronic characteristics of the substituents on the benzenoid ring, moreover, the third-order polarizability regularly varies with the polymerization degrees.
文摘Nanocrystalline powders in the Ni-Ti and Ni-Cr systems were prepared by mechanical alloying (MA) of elemental crystalline powders in an inert atmosphere. The microstructure of the mechanically alloyed powders were characterized by XRD and TEM. The ball-milling process results in a drastic decrease of the crystallite size to the nanometer scale. X-ray diffraction analysis reveals that in the Ni-Cr system, no diffraction peaks from NiCr compound were observed even after 20 h of bail milling; while the lattice parameter of Ni increased with the milling time. In the Ni-Ti system, amorphous alloy was formed. Crystalline intermetallic compounds were obtained by post heat treatment of the amorphous alloy. The crystallization temperature of the amorphous NiTi alloy was obtained by DSC measurement.
文摘High purity hot hydrogen charging at high temperature was used to investigate the hydrogen embrittlement (HE) of JBK-75 alloys with different contents of P and Si(Mn). The results indicated that by lowering P content, the size and distribution of gamma' precipitate became more homogeneous and the precipitation of stable phase eta was retarded, thus the hydrogen resistant properties of the alloy was obviously improved; however, when Si(Mn) content was lowered together with P, though the size and density of gamma' were also homogeneous and no eta phase was observed, formation of some micro twin around grain boundaries was found to be detrimental to the hydrogen performance of the alloy, and hydrogen induced loss of area reduction was very high. Therefore, to improve the hydrogen resistant properties of the alloy, P content should be lowered while certain amount of Si(Mn) should be kept.
文摘The quantitative structural parameters and activity relationship of pyrrolobenzothiazepin-ones and pyrrolobenzoxazepinones' inhibitory activities on HIV-1 reverse transcriptase (RT) was studied. A good relationship has been built.
