Probing the halo and cluster structure of exotic nuclei

The Halo and cluster structure at the ground state of unstable nuclei are among the most exciting phenomena of current nuclear physics. Probing these structures requires a careful selection of reaction tools. In the past twenty years, knockout reactions have been used intensively to investigate spectroscopically the structure of unstable nuclei. In this report we have illustrated the latest development of the knockout reaction tool and have emphasized the recoiled proton tagging method. A quantitative criteria is developed to evaluate the quasi-free feature of the knockout process. The newly discovered "towing mode" reaction tool is also outlined and its applicability at transit energies is discussed.     

在险风险值估计方法的比较研究

金融数据呈现的厚尾性已达成共识。本文首先基于指数回归模型提出了一种厚尾分布的极值分位数估计方法,得到了在险风险值的估计公式。然后得到了上海上证指数、国债指数和企业债券指数的在险风险值的估计值,比较了他们的极值风险.     

金属网的静电屏蔽效果

金属网的静电屏蔽效果高振金，唐恩辉（东北师大物理系长春１３００２４）我们用不同形状和大小网孔的金属同做静电屏蔽实验，发现其屏蔽效果不同．实验器材１．半径为１０ｃｍ，长为ｌｍ，网孔形状为正方形的圆筒两个．其中一个圆简的正方形同孔的边长为０．５ｃｍ，另一...     

Spectroscopic characterization of mechanisms of oxidation of Phe by SO_4~- radical: A pulse radiolysis study

By using time-resolved kinetic spectrophotometry and pulse radiolysis technique, the oxidation of Phe by SO4- radical has been investigated both in aqueous and water/acetonitrilemixed solutions. The results reveal that attack of the oxidizing SO4- radical on Phe leads directlyto the formation of Phe cation radical 3 with a strong absorption peak at 310 nm, then it proceeds in three competitive reactions via either hydroxylation, deprotonation or decarboxylation, which were found to be strongly dependent upon the ionization state of the substitutes -COOH and -NH2 and the nature of the solvents. Decarboxylation takes place only when the carboxyl group is deprotonated. At high pH deprotonation of Phe cation radical 3 is much easier to occur than that in neutral or acid solutions. Moreover, with addition of acetonitrile, deprotonation is more predominant than hydroxylation, whereas in aqueous solutions hydroxylation is much easier to occur.     

由联烯酸酯类化合物合成头孢克洛母核7-苯乙酰基3-氯-3-头孢烯4-羧酸对甲氧基苯甲醇酯

由青霉素G经扩环合成新的具有广谱抗菌作用的头孢类化合物一直是工业界和有机化学工作者感兴趣领域[1,2].我们课题组研究成功了由青霉素G的开环产物SOP化合物1,开始,经臭氧化、甲苯磺酰化合成联烯酸酯化合物3,再经过合环,合成了7-苯乙酰基3-氯-3-头孢烯4-羧酸对甲氧基苯甲醇酯(5),总收率为63.2%.具有广泛的应用前景.     

贵金属元素电分析化学研究Ⅹ Ⅵ铱(Ⅳ)-半胱氨酸络合物催化极谱氢波的研究

本文研究了Ir(Ⅳ)-半胱氨酸(Cys)-HCl体系的催化极谱氢波的反应机理,证明Ir(Ⅳ)与Cys形成的络合物可催化氢在电极上放电,并提出了测定实际样品的方法。     

1-苯基-3-甲基-七氟丁酰吡唑酮-5(PMHFP)及邻菲咯啉(phen)希土混配配合物的合成及性质研究

本文在乙醇中合成了PMHFP及phen与希土离子的三元配合物Ln(PMHFP)₃·phen(Ln=La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu,Y).通过化学分析,元素分析及电导分析确定了配合物的组成;研究了配合物的紫外、红光光谱;借助于差热-热重分析仪研究了所有配合物的挥发性质,测定了它们各自的起始挥发温度,探讨了用于希土分析的可能性.     

石英晶体微天平技术研究纳米TiO2表面Cu(Ⅱ)吸附与光化学还原过程

The adsorption and photochemical reduction process of Cu(Ⅱ) at the surface of nanocrystalline TiO₂ was investigated using in situ quartz crystal microbalance(QCM). It was found that the adsorption of Cu(Ⅱ) onto active sites of nanocrystalline fit the pseudo-second-order reaction better than the pseudo-first-order reaction, and that the rate constant of the reaction was estimated to be about 0.09 g·mmol₂·min₂. In addition, it was also found that the adsorption amount of Cu(Ⅱ) at the surface of TiO₂ was affected by pH、concentration and coexisting anions, and the saturated amount of adsorbed Cu(Ⅱ) was approximately 1.5 mmol·g^-1 at pH 4. During UV illumination, the frequency of QCM decreased gradually, which meant the photoreduction deposition of Cu(Ⅱ) from the solution, moreover, the rate of photodeposition of Cu(Ⅱ) increased with increasing pH of solution, and the rate of photoreduction enhanced obviously when the organics were introduced.     

Nonlinear theory of combustion stability in liquid rocket engine based on chemistry dynamics

Detailed models of combustion instability based on chemistry dynamics are developed. The results show that large activation energy goes against the combustion stability. The heat transfer coefficient between the wall and the combust gas is an important bifurcation parameter for the combustion instability. The acoustics modes of the chamber are in competition and cooperation with each other for limited vibration energy. Thermodynamics criterion of combustion stability can be deduced from the nonlinear thermodynamics. Correlations of the theoretical results and historical experiments indicate that chemical kinetics play a critical role in the combustion instability.     

以重铬酸钠—硫酸作氧化剂合成1,3—二氯丙酮

用重铬酸钠—硫酸作氧化剂,由1,3-二氯-2-丙醇氧化合成1,3-二氯丙酮。反应产物经乙醚萃取、正已烷重结晶,得白色针状或片状结晶,1,3-二氯丙酮收率81×10(-2),纯度>90×10(-2)。