预辐射苯乙烯形成过氧化物组分结构及其引发活性研究

本文研究了苯乙烯在空气存在下的γ辐照。用硅胶柱层析分离在辐射总剂量为5×10^4Gy, 辐射剂量率分别为2.9, 0.7, 0.5和0.3Gy/s的条件下形成的过氧化物,发现剂量率在0.5Gy/s以上时产物都可分成三种组分, 而组分布随剂量率不同而异。当剂量率为0.3Gy/s时, 产物只包含单一的, 相当于第二组分的过氧化物。对剂量率为0.7Gy/s时生成的三种过氧化物组分用红外光谱, 核磁共振谱和质谱进行了组分结构测定及其引发活性测定, 发现具有交替结构的第二组分有较强发引发活性, 它在较低温度和较短时间内就能引发苯乙烯聚合, 获得分子量166578的聚合物。它还能引发其它乙烯类单体聚合, 且聚合过程较用BPO引发剂平稳。     

超声波辐射下固-液相转移催化法合成N-(α -萘乙酰基)-N'- 芳基硫脲化合物

利用超声波辐射固－液相转移催化法合成了十三种未见文献报道的N(α-萘乙酰基)-N'-芳基硫脲新化合物,并经IR,1^HNMR,13^CNMR和元素分析确定了它们的结构。初步考查它们对玉米生长的促进作用,初步生物活性实验结果表明所有合成的化合物在(0.1～10)×10^-6的浓度内对玉米的根部生长具有显著的促进作用,部分化合物对玉米的幼苗具有促生长作用。     

XeCl准分子激光引发香芹酮的化学反应

本文报道了用XeCl准分子激光引发香芹酮(1)化学反应的研究结果.根据反应产物香芹酮樟脑(2)和1-挂,5-二甲基-顺2-[(乙氧羰基)甲基]双环[2.1.1]己烷(3)与激光照射能量的关系,得出香芹酮的1→2→3的反应过程.实验表明,在低激光强度照射时,每照射1焦耳能量生成2和3的量随着激光强度的增加而增加,并显示出饱和趋势.同时在照射过程中观察到浓度效应和发光.     

Simulating the Performance of Michelson- and Sagnac-based Laser Interferometric Gravitational Wave Detectors in the Presence of Mirror Tilt and Curvature Errors

We model the behaviour of single-bounce delay-line dual recycled Sagnac-based interferometer and compare its performance with that of single-bounce Michelson-based system. Geometric imperfections such as mirror tilt and curvature mismatch can strongly influence the performance of the Sagnac device due to the inherently smaller free spectral range (FSR) and higher order mode spacing. This leads to a greater number of higher order modes near, or within the signal band in the signal recycling cavity of the instrument. The important consequence of that is, in general, a greater sensitivity of a Sagnac system to nonideal parameters and imperfections of various kind affecting the performance of a real interferometer. A number of optical configurations have also been examined numerically to determine the best possible optical arrangement, in the presence of such geometric imperfections. We show that there is an optimum choice for the nominal radius of curvature of the end mirrors which results from balancing the loss due to mirror tilt against that due to curvature mismatch.     

六氟化铀振动激发态的紫外吸收变化

本文以脉冲CO2激光激发SF6分子,经碰撞V-V传能产生UF6振动激发态,在波长220-330nm范围内研究其紫外吸收瞬时变化.在静态池的条件下,分别测定了脉冲CO2激发能量以及SF6和UF6的分压对紫外吸收变化的影响,曾对2.0TorrSF6和2.0TorrUF6混合气体在激光脉冲能量为160mJ时,振动受激的UF6分子的紫外吸收变化与波长的关系作了研究,发在在240,248,290和313nm处有明显的吸收变化的峰值,这可能系几种不同的高振动态SF6分子的吸收截面的变化所引起的.     

化学反应的内禀反应坐标法I:甲硫醛脱氢反应的IRC解析

本文用内禀反应坐标法讨论了甲硫醛分子的脱氢反应机理. 在4-31G基组上对此反应做了量子化学从头计算和反应路解析, 得出过渡态结构, 反应势能曲线, 活化能, 反应热以及沿反应坐标反应系的一些物理量的变化, 并对过渡态做了振动分析. 所得结果与甲醛,甲硫醇和甲醇等分子的脱氢反应结果做了对比. 还给出沿反应坐标分子间弹性碰撞阶段和最佳碰撞角等信息. 同时, 计算了反应的频率因子A,讨论了反应速率常数k值与温度的关系.     

γ辐照 聚全氟乙丙烯(F46)的电子自旋共振研究 I.真空中俘获自由基的定量研究

A method for determining respectively the concentration of free radicials...CF2-CF2.(RI), ...CF2-CF-CF2...(RII)and...CF2- C(CF3)-CF2...(RIII) trapped in γ-irradiated F46 in vacuum at room temperature by analysing the ESR overlapping spectra is proposed. A quantitative relation between the concentration of free readicals and the total dose of γ-irradiation has been studied. The generating rate o free radicals caused by irradiation, i.e. G-value, has been calculated; it is 2.0 for RIII, 1.2 for RI, and 0.59 for RII. the magnitude of G value of free radicals is in the reverse order of their stability. Hence, we assume that the G value of free radicals in F46 mainly depends on the escaping rate of F2 and other fluorine-containing small molecules from surface of polymer into space. Therefore the looser the molecular chain, the larger becomes the G value of free radical. From that, we consider that both unstable free radicals RIII and RI with larger G-value mainly locate in the amorphous region, and the stable free radical RII with lower G-value is in the crystalline region. Recombinations between free radicals RII and RIII, or between RII and RI are forbidden at the temperature lower than 80C. An explanation for the saturation phenomenon of concentration of free radicals is given.     

VARIATION OF PHYSICO-CHEMICAL PROPERTIES OF RADIATION CROSSLINKED RUBBER WITH STORAGE TIME

The effect of storage on physico-chemical properties of non-irradiated natural rubber and radiation vulcanized natural rubber （RVNR） were evaluated. The rubber films were stored under two different conditions, namely in open air and sealed polyethylene bags. The antioxidant, tris（nonylated phenyl） phosphite （TNPP） was used for preventing degradation of RVNR films. Gel content, cross-link density, tensile strength at break and 500% elongation of rubber films were measured. The results show that the retention （%） of tensile properties of rubber films with TNPP is higher than that of rubber films without antioxidants. The rubber films stored in polyethylene bags also show better retention of tensile properties than those of rubber films stored in open air.     

A STUDY ON RADIATION CROSSLINKING OFPOLYDIMETHYLSILOXANE （PDMS） RUBBER LATEX

Polydimethylsiloxane (PDMS) rubber latex with two sorts of sensitizers, trimethylol propane tri-methacrylate (TMPTMA) and diethylene glycol di-acrylate (DEGDA), was irradiated with y-rays and electron beams in various conditions. The radiation crosslinking reaction of PDMS occurs in the inner phase of the latex and is relatively isolated from the water phase. Therefore the oxygen and the radicals produced by the radiolysis reaction of water almost have no effect on the crosslinking reaction of polymer. The experimental data correspond with the Charlesby-Pinner relationship in the main. The gelation doses, degree of crosslinking and degradation as well as G values of crosslinking were calculated. From them, the sensitization coefficients were derived to offer a quantitative measurement of the enhancing effect of sensitizer on the radiation crosslinking.