共查询到19条相似文献,搜索用时 428 毫秒
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用时间分辨激光光解技术对富勒烯水溶性衍生物C_(70)富勒醇[C_(70)(OH)_m]研究发现,与通常富勒烯衍生物,如C_(60)[C(COOEt)_2]_n,C_(60)(C_4H_6O),C_(60)(C_3H_7N)在溶液中光解常产生激发三重态不同,C_(70)富勒醇能被248nm激光单光子电离。以KI溶液为参照,测定其水合电子的量子产额(Ф_(e-))为0.11。将激光光解与SO~-的氧化对比,确认了到C_(70)富勒醇阳离子自由基的吸收峰。 相似文献
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二硫化碳自由基中间体的瞬态研究 总被引:3,自引:0,他引:3
用激光光解和脉冲辐解瞬态吸收光谱技术研究了二硫化碳(CS2)的光解和辐解反应机理及相应动力学特性。光解机理研究结果表明,CS2在308nm激光下生成激发三线态,该三线态与基态CS2反应产生自由基中间体,并测得了相关反应速率常数。应用脉冲辐解法进一步验证了光解中产生的CS2阴、阳离子自由基。研究结果为CS2对生物大分子的氧化性损伤假说提供了直接证据。 相似文献
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环氧有机硅阳离子光聚合引发体系的增感研究 总被引:1,自引:0,他引:1
研究了裂解型和夺氢型自由基光引发剂种类及用量对脂环族环氧官能化聚有机硅氧烷预聚物(CEPS)阳离子光聚合中二芳基碘鎓盐SR—1012引发体系增感作用的影响。结果表明,自由基型光引发剂对SR—1012有很好的增感作用,增感后的体系感应可达112.2mJ/cm^2。自由基光引发剂与SR—1012的最佳配比为不超过1:2(重量比)。 相似文献
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稀有三环核苷衍生物的光谱学研究 总被引:3,自引:0,他引:3
利用时间分辨激光光解技术对稀有三环核苷的前体化合物N - 4-desmethylwyosine(dYt)研究发现 ,该化合物能被 2 4 8nm激光单光子电离 ,但未观察到明显的激发三线态。用氧化性自由基SO4 · - 引发其阳离子自由基 ,揭示了其光电离机理。以KI溶液为参照 ,测得该化合物中性条件下的光电离量子产额 (Φe- )为 0 .0 4。 相似文献
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对-叔丁基杯[4]芳烃酮的激光光解研究 总被引:2,自引:0,他引:2
为了探讨杯芳烃及其衍生物作为聚合物稳定剂的稳定机理,用激光光解技术研究了308nm激发光条件下,对-叔丁基杯[4]芳烃酮的环已烷溶液在室温下的激光光解行为。观察到300nm、340nm、460nm和540nm4个主要吸收峰,其中,300nm和460nm分别确定为酚氧自由基和阳离子自由基的吸收峰。研究发现,酚氧自由基的生成是单光子电离过程和双光子电离过程共同作用的结果。同时讨论了对-叔丁基杯[4]芳烃酮的阳离子自由基在460nm的吸收峰随溶剂和pH值变化的趋势。结果表明,对-叔丁基杯[4]芳烃酮受到激发后形成相对稳定的酚氧自由基是其作为聚合物稳定剂的原因之一。 相似文献
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用傅里叶变换光声光谱(FTIR—PAS)法,研究了富氧气氛中高密度聚乙烯(HDPE)的γ射线辐照氧化,辐照时间与HDPE氧化状态之间的关系。用傅里叶变换红外光谱(FTIR)研究表明,经过辐照的HDPE与PA6(尼龙—6)熔融共混时发生了化学反应,改善了相容性,扫描电镜(SEM)测试结果也直观地给予了证明。 相似文献
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In this paper the sensitivity and uncertainty analysis of the anomalous diffusion exponent (ADE) in the Time-Fractional Telegrapher's Equation P1-approximation (TFTE) for the motion neutron, is presented. This analysis was carried out through implementation of the Monte Carlo simulations in the numerical solution of TFTE, where the samples of random numbers for simulation of sizes up to 65,000 were considered for the simulations. The sensitivity was evaluated in terms of 99% confidence intervals of the mean to understand the range of mean values that may represent the entire statistical population of performance variables. The uncertainties were propagated as follows: for 10% change in the ADE, the responses for flux scalar changed by 39.36% (most greater variation) for highly scattering medium, and the least variation of only about 0.49% was found for purely absorbing medium. 相似文献
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《等离子体科学和技术》2016,18(8):798-803
The frequency dependent permittivity for dusty plasmas is provided by introducing the charging response factor and charge relaxation rate of airborne particles. The field equations that describe the characteristics of Terahertz(THz) waves propagation in a dusty plasma sheath are derived and discretized on the basis of the auxiliary differential equation(ADE) in the finite difference time domain(FDTD) method. Compared with numerical solutions in reference, the accuracy for the ADE FDTD method is validated. The reflection property of the metal Aluminum interlayer of the sheath at THz frequencies is discussed. The effects of the thickness, effective collision frequency, airborne particle density, and charge relaxation rate of airborne particles on the electromagnetic properties of Terahertz waves through a dusty plasma slab are investigated.Finally, some potential applications for Terahertz waves in information and communication are analyzed. 相似文献
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ZHU Guanglai~ 《核技术(英文版)》2007,18(1):16-19
Photoinduced chemical reactions of 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF_6]) were studied by laser photolysis at a wavelength of 266 nm.Excited triplet state ~3[bmim]~ was observed,radical cation [bmim]~(2 ) and neutral [bmim] radical via photoionization were also formed.Energy transfer from ~3[bmim]~ toβ-carotene was confirmed.Oxidation via one electron transfer from TMPD to ~3[bmim]~ was also observed and the rate constant was determined to be 1.2×10.5 L.mol~(-1).s~(-1).The reaction of [bmim][PF_6] with hydrated electron (e_(aq)) was confirmed by laser photolysis in aqueous solution. 相似文献
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以对-硝基苯甲酸为模型,探索两个取代基处于对位而同时不溶于水但溶于有机溶剂的芳香族硝基类有机物的光解行为,为有效降解此类化合物提供实验方法与理论支持。通过266nm激光光解和254nm紫外光降解两种手段对对-硝基苯甲酸的光解行为进行了研究,考察了不同体系对对-硝基苯甲酸光解行为的影响,并获得了相应的ns级激光光解瞬态吸收光谱及紫外光降解效果,为其降解机理研究奠定了基础。通过实验发现,在激光光解条件下,310nm附近有激发三线态的生成;紫外光难以直接降解对-硝基苯甲酸,但UV/H2O2却可提高其降解效率,经分析,认为H2O2在紫外光作用下产生的.OH起到了关键性作用。 相似文献
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利用激光光解时间分辨吸收方法,对蚕砂叶绿素中提取的焦脱镁叶绿酸-a的光化学性质进行了初步的研究。发现,该化合物在实验检测的波长范围内都有较强的吸收,且能产生较高量子产额的三重激发态。进而讨论它作为光活化农药的可能性。 相似文献
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《Annals of Nuclear Energy》1986,13(7):379-390
New finite-element formulations based on numerical integration of mass and stiffness matrices have been used for solving the time-dependent multigroup diffusion theory equations in multidimensions. There is a drastic reduction in the coupling of the nodal unknowns. This facilitates the use of a fast and stable time integration scheme, viz. an alternating-direction explicit (ADE) algorithm. Frequency transformation is used to limit the truncation error due to temporal differencing. This model is incorporated in a code called fintran. Analyses of 2-D and 3-D reactor transients indicate that the present method can be as efficient as other fast nodal methods. 相似文献
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ZHUDazhang WANGShilong SUNXiaoyu LIWenzhe ZENGKailing NIYaming WANGWenfeng YAOSide 《辐射研究与辐射工艺学报》2005,23(2):74-74
Quinoline and some of its derivatives were reported to be carcinogenic, toxic and mutagenic. The widespread use of quinoline and its derivatives entails that these compounds are distributed in the environment, polluting soil and water together with many other environmental chemicals. 相似文献
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采用γ射线辐照、激光光解和脉冲辐解技术,就海藻酸钠水溶液分子量与辐照剂量的关系,SO4^*-氧化切断海藻酸钠C1-O-C4键的机理开展研究。探索了海藻酸钠辐射降解规律,推导其在γ射线照射下的降解,主要由水辐解产物羟基自由基进攻其C1-O-C4键,导致链断裂引起的。 相似文献