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脉冲辐解

脉冲辐解的相关文献在1990年到2021年内共计81篇,主要集中在化学、药学、生物化学 等领域,其中期刊论文72篇、会议论文7篇、专利文献85919篇;相关期刊21种,包括科学技术与工程、含能材料、核化学与放射化学等; 相关会议7种,包括2010年全国辐射技术与辐射改性材料发展论坛、中国核学会2009年学术年会、中国科协2005年学术年会——生物物理与重大疾病分会等;脉冲辐解的相关文献由137位作者贡献,包括姚思德、汪世龙、孙晓宇等。

脉冲辐解—发文量

期刊论文>

论文:72 占比:0.08%

会议论文>

论文:7 占比:0.01%

专利文献>

论文:85919 占比:99.91%

总计:85998篇

脉冲辐解—发文趋势图

脉冲辐解

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  • 姚思德
  • 汪世龙
  • 孙晓宇
  • 王文峰
  • 倪亚明
  • 王文锋
  • 付海英
  • 钱素平
  • 吴国忠
  • 林维真
  • 期刊论文
  • 会议论文
  • 专利文献

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    • 胡长江; 马骏
    • 摘要: 溶剂化电子是自然界中最小的阴离子和最强的还原性粒子,也是辐射化学反应过程中重要的活性物质.溶剂化电子的研究将为溶液自由基反应、乏燃料后处理中溶剂与萃取剂的辐射化学、生命过程的电荷转移与电荷传输等领域提供关键信息,因此是有机化学、无机化学、辐射化学和放射生物学研究中的重要课题.近年来,随着短脉冲激光技术的新一轮革命,有关溶剂化电子的研究迎来了新的一轮爆发增长期.为此,本文力图概述当前溶剂化电子研究的前沿进展,主要内容涉及溶剂化电子结合能的测定、溶剂化电子的表面态以及预溶剂化电子和准自由电子与核苷酸分子的反应动力学等.
    • 郭建华; 肖松涛; 叶国安; 欧阳应根; 赵晶
    • 摘要: 研究了脉冲辐解过程中氨基羟基脲与水辐解活性粒子(ea-q、·O H和·H)及单电子氧化剂·CO3-的反应动力学过程.反应近似为准一级反应,反应速率常数分别为k(ea-q)=1.41×108 L/(mol·s)、k(·OH)=1.05×1010 L/(mol·s)、k(·H)=2.68×105 L/(mol·s)、k(·CO3-)=4.25×108 L/(mol·s).其中氨基羟基脲与·OH的反应速率常数最大,故在辐解过程中其为主要反应.
    • 吉天翼; 刘艳成; 赵剑锋; 徐刚; 王文锋; 吴明红
    • 摘要: 本文运用脉冲辐解探究了不同自由基与药物氟西汀(FLX)之间的反应.羟基自由基(·OH)与FLX反应生成苯环上的羟基加成物,而硫酸根阴离子自由基(SO4·-)则通过单电子氧化FLX生成苯阳离子自由基,该中间产物再进一步与水反应生成苯环上的羟基加成物.本研究测定了三种自由基·OH,水合电子(eaq-)以及SO4·-与FLX反应的反应速率常数分别为:7.8×109,2.3×109和1.1 x 109 mol·L-1·s-1.本文还运用电子束辐照技术探究了不同辐照条件下的FLX降解效果,结合HPLC和紫外可见光谱仪进行分析.在N2O和空气饱和的两种条件下,FLX溶液经1.5 kGy辐照后降解效率均达到90%以上,而N2饱和条件下,加入0.1 mol·L-1的叔丁醇的FLX溶液经1.5 kGy辐照后仅有43%分解.此外,酸性和中性条件下FLX的降解效率均大于碱性条件下的.结果阐明了饱和空气的FLX溶液在中性条件下的降解效果最佳,且·OH诱导的反应比SO4·-更有利于FLX的分解.本研究期望对于进一步探究FLX的降解反应提供有益的帮助.%The reactions of the pharmaceutical fluoxetine (FLX) with different radicals were investigated by pulse radiolysis.The reaction of hydroxyl radical (· OH) with FLX formed hydroxylated adduct of the aromatic ring,while oxidation of FLX by sulfate radical anion (SO4·-) formed benzene radical cation that further reacted with H2O to yield the · OH adduct.The determined rate constants of · OH,hydrated electrons (eaq-),and SO;with FLX were 7.8 × 109,2.3 x 109,and 1.1 × 109 mol·L-1 ·s-1,respectively.In the steady-state radiolysis study,the degradation of FLX in different radiolytic conditions by electron beam irradiation was detected by HPLC and UV-Vis spectra techniques.It was found that FLX concentration decreased by more than 90% in both N2O and air-saturated solutions after 1.5 kGy irradiation.In contrast,only 43% of FLX was decomposed in N2-saturated solution containing 0.1 mol· L-1 tea-butanol.The degradation rates of FLX in acidic and neutral solutions were higher than those in alkaline solutions.Our results showed that the degradation of FLX is optimal in air-saturated neutral solution,and · OH-induced degradation is more efficient than SO4·-oxidation of FLX.The obtained kinetic data and optimal conditions give some hints to understand the degradation of FLX.
    • 李海霞; 周保昌; 刘艳成; 唐睿智; 张鹏; 李景烨; 王文锋
    • 摘要: 对二氟沙星在中性水溶液中的光化学性质进行了研究.在pH值为7.17的水溶液中二氟沙星的紫外吸收峰位于273 nm (摩尔消光系数ε=33000 dm3∙mol-1∙cm-1),323 nm (ε=15500 dm3∙mol-1∙cm-1),335 nm (ε=15500 dm3∙mol-1∙cm-1)处.荧光吸收和发射光谱均显示二氟沙星具有pH效应,其pKa(电离平衡常数)测定分别为5.9和9.8.二氟沙星的荧光量子产额较低,在pH=3.00时达到最大值,为0.06.同时对二氟沙星在中性水溶液中的激光光解和脉冲辐解进行详细研究.激光光解研究发现在水溶液中二氟沙星的三重激发态位于620 nm,其摩尔消光系数为7900 dm3∙mol-1∙cm-1.通过能量转移的方法得到其三重激发态的能量为263.5 kJ∙mol-1,三重激发态的量子产额为0.21.在激光激发下,二氟沙星进行单光子电离其量子产额为0.02.脉冲辐解研究表明二氟沙星可以与水合电子(e-aq)及羟基自由基(∙OH)快速反应,其二级反应动力学常数分别为1.72×1010和1.0×1010 dm3∙mol-1∙s-1.本文对二氟沙星光化学性质的研究有助于确定其光敏毒性的产生机理.%The photochemical properties of difloxacin (DFX) were investigated in neutral aqueous solution. DFX aqueous solution showed intense absorption with one peak at 273 nm (molar absorption coefficientε=33000 dm3∙mol-1∙cm-1) and two other peaks at 323 and 335 nm (ε=15500 dm3∙mol-1∙cm-1) with the same molar absorption coefficient. Both the absorption and emission properties of DFX were pH-dependent. The acid dissociation constant (pKa) for the protonation equilibria of the ground state (5.9 and 9.8) were determined spectroscopical y. DFX fluoresces weakly, and its maximum quantum yield for fluorescence emission was 0.06 at pH 3. Laser flash photolysis and pulse radiolysis studies were carried out to characterize the transient species of DFX aqueous solution. Triplet-triplet absorption reached a maximum at 620 nm with a molar absorption coefficient of 7900 dm3∙mol-1∙cm-1. The energy transfer method was used to estimate the triplet energy of DFX, which was 263.5 kJ∙mol-1. The quantum yield of triplet formation was determined to be 0.21. Furthermore, DFX showed monophotonic photoionization with a quantum yield of 0.02. Pulse radiolysis indicated that DFX could react with e-aq and∙OH, and the bimolecular rate constants for these reactions were 1.72×1010 and 1.0×1010 dm3∙mol-1∙s-1, respectively. It is expected that this research may be helpful in determining the phototoxicity mechanism of DFX.
    • 张福根; 周瀚洋; 彭静; 吴季兰
    • 摘要: 由于脂质过氧化反应(LPO)是导致人体疾病(如肝炎、肝硬化、动脉硬化、脑溢血等)的主要原因,而黄酮类化合物是一类很强的过氧化反应抑制剂,因此有必要研究其化学结构与过氧化反应的关系及其抗氧化机理.本文选择α-羟乙基过氧自由基为脂质过氧自由基的模拟物,采用脉冲辐解方法研究了乙醇溶液中4种典型的黄酮类化合物(槲皮素、芦丁、儿茶素以及黄岑甙)与α-羟乙基过氧自由基的反应动力学,测得其反应活性顺序为:芦丁>槲皮素>黄岑甙>儿茶素.同时以黄酮体和邻苯二酚为黄酮类化合物不同结构特征的模型化合物,用脉冲辐解法测得二者与α-羟乙基过氧自由基的反应速率常数分别为(1.7±0.1)×106和(2.9±0.1)×105 mol-1·dm3·s-1.实验结果表明,在黄酮类化合物与α-羟乙基过氧自由基的反应中, A环C5位的羟基, C环C2=C3或B-C环的大π键和B环邻二羟基共存时清除α-羟乙基过氧自由基活性最好,而且C环C2=C3或B-C环大π键的清除活性好于B环邻二羟基,同时C环是否含有C3-醣甙结构对清除作用没有明显影响.因此我们推测在黄酮类化合物抑制脂质过氧化反应过程中,起主要作用的是C环C2=C3或B-C环的大π键与脂质过氧自由基的双键加成反应.%Lipid peroxidation (LPO) plays an important role in many pathological processes (such as hepatitis, hepatic sclerosis, atherosclerosis, cerebral hemorrhage and so on), and flavonoids are considered to be effective LPO-inhibitors. Thus we investigated the relationship between the chemical structure of flavonoids and the LPO activity and the antioxidant mechanism of flavonoids. In this work,α-hydroxyl ethyl peroxyl radicals were produced from radiolysis of aerated ethanol to model lipid peroxyl radicals. By detecting the decay of α-hydroxyl ethyl peroxyl radicals in the presence of different concentrations of flavonoids using pulse radiolysis, the reaction rate constants ofα-hydroxyl ethyl peroxyl radicals with quercetin, rutin, catechin, and baicalin are determined for the first time. The antioxidant activity of these flavonoids decreases in the order: rutin>quercetin>baicalin>catechin. Flavone and pyrocatechol were used as model compounds for the different components in flavonoids and their reaction rate constants towardsα-hydroxyl ethyl peroxyl radicals were (1.7±0.1)×106 and (2.9±0.1)×105 mol-1·dm3· s-1, respectively. The effect of chemical structure on the scavenging activity towards α-hydroxyl ethyl peroxyl radicals was investigated. The coexistence of the C5-hydroxyl group in the A ring with the C2=C3 in the C ring or the conjugated double bond of the B-C ring and the catechol group in the B ring provides the best antioxidant activity. In addition, the C2=C3 in the C ring or the conjugated double bond of the B-C ring is more effective than the catechol group in the B ring, while the C3-rutinose in the C ring has no obvious effect. Therefore, we conclude that the addition reaction between double bonds with peroxyl radicals plays an important role in the antioxidant activity of flavonoids in LPO.
    • 陈辉; 何辉; 叶国安; 付海英; 吴国忠
    • 摘要: Pulse radiolysis of aqueous methylhydrazine solutions under different conditions was studied. The main characteristic peaks in these transient absorption spectra were attributed and the build-up/decay trends of several transient species were investigated. The reaction product of ·OH radical and methylhydrazine is CH3 · NNH2 radical with a rate constant of (2. 4 ± 0. 1) × 10 10 mol-1 · L · s-1. The reaction product of e-aq and methylhydrazine is CH3 · NHNH2 radical with a rate constant of (2. 7 ± 0. 2)×108 mol"1 · L · s-1.%利用脉冲电子束进行甲基肼水溶液的脉冲辐解研究,对其瞬态光谱中的主要吸收峰作了归属,并初步考察了这些瞬态物种的生长、衰减等行为.结果表明,·OH与甲基肼反应生成CH3·NNH2,速率常数为(2.4±0.1)×1010mol-1·L·s-1;enq-与甲基肼反应生成CH3·NHNH2自由基,速率常数为(2.7±0.2)×108 mol-1·L·s-1.
    • 唐睿智; 张鹏; 李海霞; 刘艳成; 王文锋
    • 摘要: 采用纳秒级脉冲辐解技术研究了吩噻嗪与CC13OO·、·OH的反应,提出了相应的反应机理,得到了相关的反应速率常数.研究结果表明:吩噻嗪与CCl3OO·、·OH反应得到的瞬态产物的最大吸收峰都位于380nm左右,该吸收峰归属于CCl3OO·、·OH夺取吩噻嗪氮原子上的氢而产生的吩噻嗪氮自由基.吩噻嗪与CCl3OO·、·OH反应的速率常数分别为1.1×109和4.0× 109 L·mol-1·s-1.这些结果将为进一步研究吩噻嗪的抗氧化活性提供理论基础.%The kinetics and mechanisms of the reactions between phenothiazine and CCI3OO*, *OH were evaluated and the related rate constants were determined using nanosecond pulse radiolysis technique. The experimental results indicate that the maximum absorption of the transient product from the reaction between phenothiazine and CCl3OO*,*OH was located at 380 nm, which is attributed to CClOO* and *OH abstracting hydrogen from phenothiazine to generate a phenothiazine radical. The rate constants of the reactions between phenothiazine and CCl3OO*, *OH were determined to be 1.1 ×109, 4.0×109 L · mol-1 · s-1, respectively. These results provide a theoretical foundation for the further study of the antioxidant activity of phenothiazine.
    • 周佳欣; 吴明红; 姚思德
    • 摘要: Steady-state and pulse radiolysis experiments have been performed to gain insight into the mechanism of Thiamphenicol(THA) and Florfenicol(FLO) degradation in aqueous solutions.Redox reac-tions of aqueous THA and FLO solutions with ·OH,e-aq,and ·H were studied by using pulse radiolysis techniques.The results indicated that the reaction pathway between THA/FLO and ·OH was dominated by the initial solution pH value.In neutral condition,the addition reaction happened between ·OH and benzene ring.The rate constants for the reactions of ·OH with THA and FLO were found to be 1.09×108 L·mol-1· s-1 and 3.14×108 L·mol-1·s-1 respectively.But in alkaline condition,the organic bond OH-was removed by ·OH.The dechlorination of THA and FLO was caused by e-aq attacking.The ·H added on the benzene ring forming relative stable products,and the rate constants for the reactions of ·OH with THA and FLO were 3.52×107 L·mol-1·s-1 and 2.43×108 L·mol-1·s-1,respectively.The reaction in alkaline solution was also discussed.The radiolysis degradation by-products were identified by GC/MS analysis and their degra-dation pathway were also conducted.%对甲砜霉素(THA)和氟苯尼考(FLO)的辐照降解进行了瞬态产物和稳态产物的分析.利用脉冲辐解技术研究了THA/FLO水溶液在各种条件下与·OH,e-aq和·H的反应机理,研究表明:THA/FLO与·OH反应途径与pH有关:中性条件下主要发生苯环上的加成反应,其速率常数分别为为1.09×108 L·mol-1·s-1(THA)和3.14×108 L·mol-1·s-1(FLO);碱性条件下,则断裂产物在·OH催化下的去OH-反应.e-aq的进攻导致THA/FLO脱Cl-和F-,该反应中性条件比碱性条件更易进行.THA/FLO与·H发生加成反应,生成较稳定的氢加成产物,反应速率分别为3.52×107 L·mol-1·s-1(THA)和2.43×108 L·mol-1·s-1(FLO).利用GC/MS对电子束辐照的稳态产物分析,得出自由基反应生成的小分子碎片.结合瞬态反应过程,得出THA/FLO降解途径.
    • 鲍小丹; 许晨; 黄娟; 马建华
    • 摘要: 利用脉冲辐解瞬态吸收光谱技术研究了橙皮苷和柚皮苷与羟基自由基(·OH)的瞬态反应机理和动力学.研究结果表明:N2O饱和的4.9×10-5 mol·L-1的橙皮苷、5.2×10-5 mol·L-1的柚皮苷水溶液经脉冲辐解分别产生了橙皮苷酚氧自由基(特征瞬态吸收峰320nm)和柚皮苷酚氧自由基(特征瞬态吸收峰310~340nm);反应的袁观反应速率常数分别为8.38×105s-1和6.48×105s-1.橙皮苷和柚皮苷可有效清除羟基自由基.实验还从结构上探讨了橙皮苷和柚皮苷的抗氧化活性机制.
    • 陈辉; 何辉; 叶国安; 付海英; 吴国忠
    • 摘要: 利用脉冲电子束进行二甲基羟胺(DMHAN)水溶液的脉冲辐解研究,对其瞬态光谱中的主要吸收峰作了归属,并初步考察了这些瞬态物种的生长、衰减等行为.研究结果表明,OH与DMHAN反应生成(CH3)2NO·自由基,测得速率常数为(4.5±0.3)×109mol-1·L·s-1;eaq-与DMHAN 反应生成(CH3)2N·自由基,测得速率常数为(1.3±0.04)×109mol-1·L·s-1.
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