微波辐射活性炭负载磷钨酸催化合成苯乙酸β-苯乙酯

在微波辐射下,以活性炭负载磷钨酸(HPW／C)为催化剂,不用溶剂,合成了苯乙酸β-苯乙酯。优化反应条件为：负载量为23．6％的HPW／C 1g,苯乙酸30mmol,β-苯乙醇48mmol,微波辐射功率600W,辐射时间6min,产率87．3％。产物结构经IR表征。     

Fluorescence Properties of Ce+3-doped BaF2

The spectra and decay times of a serious of Ce⁺³—doped BaF₂ crystals have been determined.The results demonstrate that a BaF₂ crystal with a proper amount of Ce⁺³ doped have some outstanding advantages:a near-blue fluorescence with quite fast decay time (80ns) replaces the slow component (600ns) and vary fast one (～0.8ns) of undoped BaF₂.The intensity of the new component is comparable with the sum of the old ones.     

Experimental Measurements for the QEC-Value of 183Os-Decay

Activities of ¹⁸³Os were produced by 39MeV α particles bombarding on a natural tungsten target.β⁺ spectrum with coincidence gate set on the strongest 382keV γ-rays of ¹⁸³Os decay was measured.The endpoint energy of the β⁺ spectrum was determined and the Q_EC value of ¹⁸³Os decay was extracted to be 2.24±0.10MeV which is in good agreement with the predicted value 2.30±0.10MeV on the basis of mass systematics.     

酞菁锌衍生物L-B膜的光电性能研究

用L-B膜方法在SnO₂电极上修饰了不同链长烷氧基取代的酞菁锌化合物(ZnPc C_nH_2n+1,n=3,9,12,16),分别研究了它们单分子膜成膜性能和转移性能,并测定了修饰在SnO₂电极上的单多层分子膜的光电性能和吸收光谱。研究结果指出链短的取代基即异丙氧基取代的酞菁锌(ZnPcC₃H₇(i))具有较高的转移比及较好的光电性能。     

The Cross-Section Measurements and Evaluations for 58Ni(n,p),60Ni(n,p),62Ni(n,α) and 54Fe(n,p) Reactions

Activation techniques have been used to measure the cross-section for ⁵⁸Ni(n,p),⁶⁰Ni(n,p) and ⁶²Ni(n,α) reactions in the neutron energy range 13.6—17.8MeV.The uncertainty of measured data has been aculated from 3%—7%.The covariance matrixes for measurement error are calculated.Evaluations for ⁵⁸Ni(n,p),⁶⁰Ni(n,p),⁶²Ni(n,α) and ⁵⁴Fe(n,p) crpss-section are made.     

Measurement of Some (n,2N) Reaction Cross Sections for Producing Long Half-Life Residues

Measurement of (n,2n) reaction cross sections for some nuclides,whose residues have long half-lives,is described.The activation method relative to the ⁹³Nb(n,2n)^92mNb reaction cross section was used.The cross sections of the ¹⁵¹Eu(n,2n)^150mEu、¹⁵³Eu(n,2n)¹⁵²Eu、¹⁵⁹Tb(n,2n)¹⁵⁸Tb and ¹⁰⁹Ag(n,2n)^108mAg reactions in the neutron energy range of 13.50—14.80MeV were measured.The neutron energies in this experiment were determined by means of the method of cross section ratios for ⁹⁰Zr(n,2n)^89m+gZr and ⁹³Nb(n,2n)^92mNb reactions.The results obtained were compared with other existing data.     

Direct Radiative Capture to Continuum States

A formula for the calculation of the cross sections,of nuclear transition to continuum states induced by direct radiative capture of intermediate-energy proton is deduced.The transition amplitude includes two terms corresponding to potential-scattering to potential-scattering transitions and potential-scattering to resonance-scatting transitions,respectively.The model is compard with available experimental data of the ¹¹B(p,γ₁₉)¹²C reaction,and the results show that the direct capture mechanism is capable to account for the main features of the measured data within the reasonable parameter scope,and,in the present case,the contributions from two terms are of the same order of magnitude.The physical significance of the results is also discussed.     

Mass Shell and Even-odd Effects in Radiative Capture Reaction

This paper investigates the mass,shell and even-odd effects of the nonstatistical and statistical processes in the radiative nucleon capture reactions.The (n,γ) cross sections for 33 even-neutron target nuclides were studied at En of 0.1 to 3MeV.The results indicate that the nonstatistical capture cross sections do not present any systematically varying pattern with mass number,except for a weak shell effect.The statistical capture cross sections,which depend strongly on the level density,display obvious mass,shell and even-odd effects.The nonstatistical fractions show prominent downward tendency with mass number,as well as the shell effect.     

The Decay of 120Ba

¹²⁰Ba was produced by 68MeV ¹⁶O beam bombarding a 2mg/cm² thick ¹⁰⁶Cd target and fluorated in a halium-jet ion source.The decay of on-line mass separated activity ¹²⁰Ba has been studied by γ-X,γ-γ γ-β coincidence measurements.Its halflife was measured to be 24±2s.The total decay energy was extracted to be Q_EC=5.0±0.3MeV.A simple decay scheme has been proposed.     

硬脂酸二茂铁酯L-B膜的电化学性能研究

本文研究二茂铁衍生物——硬脂酸二茂铁酯(FcOCOC₁₇H₃₅)L-B膜技术修饰SnO₂电极的循环伏安性能.实验结果用电极表面吸附(修饰)分子的表面活度理论进行计算机拟合和此较,实验数据与理论符合较好.进一步求得修饰分子的标准电极电势和修饰量。结果表明硬脂酸二茂铁酯L-B膜电化学性能稳定,可逆性较好,可以作为快速电荷转移的修饰电极材料。