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.     

Optical fiber grating bistability

It is proposed that a segment of Er-doped fiber with a couple of fiber gratings on the ends may be used as a novel optical bistability device with low power and high speed. Operation and bistability threshold of device are analysed in accordance with the distributed feedback couple-mode theory and the nonlinear characteristic of Er-doped fiber. It is shown that a nanoseconds microwatts bistable operation of a centimeter device is realizable under nowaday technological condition. Supported by the National Natural Science Foundation of China Zhang Yuancheng: born in Aug. 1938. Professor     

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     

探地雷达在大型混凝土体质量检测中的应用

根据探地雷达的工作原理，提出了一种用于检测大型混凝土体（如桩基）质量的方法和关系式，通过实验模拟及工程应用，得出了很好的效果，这是探地雷达作为一种无损检测技术在工程应用领域的拓展     

国产石油馏份用作铜萃取稀释剂的性能考察

从我国炼油厂中选择不同的石油馏份，考察其作为稀释剂用于铜萃取工艺的可能性．测定了所选稀释剂的一些基本性能，包括稀释剂的密度、粘度、闪点等．并用各种不同的自选石油馏份分别与国际上最常用的两种铜萃取剂即Ｚｅｎｅｃａ公司的Ｍ５６４０和Ｈｅｎｋｅｌ公司的Ｌｉｘ９８４配成萃铜有机相，测绘了不同体系的萃取等温线，考察了各体系的铜萃取饱和容量、平衡ｐＨ、铜铁选择性，并与国际上通用的铜萃取用稀释剂Ｅｓｃａｉｄ１００配制的铜萃取体系的性能比较，证明自选的一部分石油馏份在性能上达到或接近Ｅｓｃａｉｄ１００的性能，可考虑用作铜萃取稀释剂．