pH effect of· OH radical induced oxidation of phosphoryl- methionine in aqueous solution

Conclusion The results of pulse radiolytical research on the · OH radical-induced oxidation of NDM in aqueous solution demonstrate that pH value has a great influence on the radiolytical mechanism of NDM. At low pH value, the product is mainly stabilization of the oxidizing sulfur centre in the three-electron-bonded cation radical NDM₂ ·⁺ [S]; with the increase of pH value, NDM₂ ·⁺ [S] gradually decays to become the reducing α-amino radical which was verified by the chemical method and whose yield was also calculated. Compared with Met₂ ·⁺ [S] produced by the · OH radical-induced oxidation in aqueous solution [1], the stability of NDM₂·⁺ [S] increases and the yield of α-amino radical decreases. This suggests that the introduction of phosphoryl group has a coordinating effect on the radioprotection of methionine to biological systems, and provides the essentially theoretical foundation for the thorough clarification of the reversible phosphorylation of proteins.     

The strong cooperativity of dioxygen binding by dicobalt (II) diporphyrin compounds in nonaqueous solution at room temperature

Thermodynamic data were determined for the reversible binding of O₂ to two compounds of dicobalt(II) di(meso-tetra-phenyl)porphyrin derivatives with different lengths of diamidoaliphatic bridge (abbreviated to Co₂PP₈ and Co₂PP₄) in N,N-dimethylformamide at room temperature. The partial pressure of dioxygen necessary for half-oxygenation (P _1/2) and hill coefficient (n) at 298 K were determined as follows:P _1/2=54.2 kPa,n=2.0 for Co₂PP₈ andP _1/2=6.8 kPa,n=1.8 for Co₂PP₄, respectively. The rate equations of reversible oxygen binding by Co₂PP₈ were determined and the reaction path was proposed. The results of ther-modynamic and kinetic studies indicate that there exists strong cooperative effect during oxygenation of the compounds. The ESR observation reveals that the dioxygen complexes formed in the solutions are of superoxo (Co-O ₂ ⁻ ) type. Supported by the Research Foundation of the State Education Commission of China Zhou Xiaohai: born in 1962, Ph.D. Associate professor     

热流模型半导体方程组的光滑解

考虑具热效应的半导体方程组的初边值问题，应用Ｓｃｈａｕｄｅｒ不动点原理和先验估计方法，证明了该问题整体光滑解的存在唯一性。     

多效唑对幼年桃树生长发育的影响

多效唑施于土壤中，对雨花露桃的营养生长有明显的抑制作用，但能增加叶绿素含量，促进成花，改变果形指数；在蟠桃上叶面施多效唑对其营养生长和生殖生长影响不明显，但明显地改变果形指数。土壤的最佳处理浓度为０．８ｇ／ｍ＾２。     

HDEHP萃取Zn(Ⅱ)的稀释剂效应

考察了ＨＤＥＨＰ在不同稀释剂中对Ｚｎ（Ⅱ）的萃取平衡，探讨了萃取平衡常数与稀释剂性质间的关系，建立了平衡常数与稀释剂极性参数（ＤＰ和Ｓ）间的经验方程．求得萃合物ＺｎＡ２·２ＨＡ的溶解度参数为１６．５Ｊ１／２．ｃｍ－３／２．     

有机过氧化物与药物体系引发烯类聚合反应的热效应

研究了有机过氧化物（ＢＰＯ）分别与含叔胺基结构的药物（如利福中，奋乃静，水杨酸毒扁豆碱，硝酸毛果芸香碱）组成的引发体系，在４０℃的温度下引发甲基丙烯酸β羟乙酯（ＨＥＭＡ）聚合的放热过程，并与纯ＢＰＯ、ＢＰＯ－ＤＭＴ体系引发ＨＥＭＡ聚合的放热过程比较．实验表明：（１）有机过氧化物与药物引发体系的引发机理与氧化还原引发体系的引发机理相似，其引发活性比ＢＰＯ－ＤＭＴ体系的低．（２）有机过氧化物与药物引发体系，能在４０℃温度下引发ＨＥＭＡ聚合成型，聚合过程放热较为平稳     

“移就”与“TransferedEpithet”的异同

汉语修辞学中的“移就”辞格与英语修辞学的ｔｒａｎｓｆｅｒｒｅｄｅｐｉｔｈｅｔ（修饰语移置）在定义、结构、内容、修辞效果与语义联系上有许多相同之处。对比一下这两种辞格，可以发现易位和词语的重新搭配是它们的共同特征。然而在语义联系上英汉这两种辞格又各有其独特的语义组合关系     

贵州喀斯特民族旅游区旅游效应及其空间辐射研究——以龙宫为例

喀斯特民族旅游在贵州旅游业中占有重要地位。本文以龙宫为例，通过抽样调查，揭示喀斯特民族旅游区旅游效应及其空间辐射的基本特征；探讨其成因机制；提出喀斯特民族区旅游开发的误区