60Coγ射线辐照对东方百合不定芽生长和生理特性影响的初步研究

用60Coγ射线以不同辐照剂量(0、0.5、1.0、2.0、4.0、6.0和8.0Gy)对东方百合索邦(Sorbonne)的离体不定芽进行辐照处理,研究辐照对东方百合不定芽生长及生理影响效应.结果表明:随着辐照剂量的增加,东方百合不定芽的丙二醛(Malondialdehyde,MDA)含量、细胞膜渗透性呈上升趋势;辐照剂量≥2.0Gγ百合不定芽的超氧阴离子(Superoxide anion,O2)含量和过氧化氢酶(Catalase,CAT)活性高于对照,出芽率小于对照;辐照剂量≥4.0Gγ百合芽高的增量小于对照.说明60Coγ射线辐照对东方百合不定芽的生长有抑制作用.通过综合考虑分析,试验推测60Coγ射线处理东方百合索邦(Sorbonne)组培不定芽的适宜辐照剂量在2.0-4.0Gy之间,其半致死剂量为4.0-6.OGy.     

典型黄酮类化合物在清除超氧阴离子自由基过程中产生的过氧化氢的测定方法(2)

用动态吸附的方法对几种典型的黄酮类化合物的甲酸钠水溶液 (N2 O:O2 =4:1饱和 )经γ辐照后产生的过氧化氢进行了分离 ,测定了辐照生成的过氧化氢的G值 ,得到了与前人不同的结果 ,并分析了产生分歧的原因。提出并确立了测试的方法 :准确测定黄酮类化合物辐照体系中的过氧化氢G值 ,必须先用柱色谱法将过氧化氢从辐照体系中分离出来再进行测定 ,再扣除黄酮类化合物因自氧化而产生的过氧化氢的量 ,才能得到辐照产生的过氧化氢G值。N2 O:O2 =4:1饱和芦丁、黄芩甙和儿茶素的甲酸钠水溶液经γ辐照后产生的过氧化氢G值分别为 8.3± 0 .2、5 .6± 0 .2和 7.8± 0 .2。     

软X射线同步辐射对小麦细胞膜脂质过氧化产物及相关酶活性的影响

采用不同剂量的软X射线辐照处理小麦种子，研究了种子的萌发率、幼苗组织细胞的脂质过氧化作用的产物及其相关酶活性变化等生物效应。同时，还对其作用机理进行了初步探讨。结果表明：在剂量为72—216J／cm^2范围内，小麦种子萌发率随剂量的增加而增加，但随后急剧下降；在剂量为72—216J／cm^2范围内，脂质过氧化作用产物丙二醛(MDA)的含量随剂量增加而增加；其相关的过氧化保护酶：过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)等并不随MDA增加而稳定增加，并且三种酶之间的活性变化不表现出明显的同步性，存在相互协调的关系；叶绿体中叶绿素含量及抗坏血酸过氧化物酶(APX)的活性始终低于对照组。     

LiF晶体中色心的吸收光谱与正电子湮没辐射多普勒展宽研究

我们用吸收光谱与正电子湮没方法研究了辐照LiF中的色心。样品是纯的LiF单晶。用~(60)Co的γ射线在室温下照射样品。当剂量的变化范围为1×10~5rad—1.3×10~8rad时,LiF晶体中出现了F、F_2、F_2~ 、F_3、F_4、R_1和R′等色心,由于受光谱仪波长范围的限制,F_2~-未观察到。当照射剂量小于1×10~6rad时,我们得出F-心浓度、S-参数的相对变化是剂量平方根的线性函数。然而,当剂量大于1×10~6rad,由于F-聚集心的出现,S-参数正比于照射剂量的对数。     

低能氮离子注入对大豆幼苗脂质过氧化的影响

用N+注入丰豆101的种子,采收子叶伸展后24h和96h的幼苗做为试验材料,研究N+注入对其幼苗过氧化物酶(POD)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性以及氧化产物丙二醛(MDA)的含量、电解质外渗率的影响。结果表明,在25keV能量下,当N+注量在6.5×1016-7.8×1016N+/cm2时,幼苗的SOD和CAT活性最高。 而POD活性在小于5.2×1016N+/cm2低剂量下, 活性较恒定, 在大于5.2×1016N+/cm2中高剂量下,活性逐渐增大。此外,N+注入还可降低幼苗子叶中的MDA积累量和电解质外渗率,而且在6.5×1016N+/cm2剂量下,幼苗中的MDA含量和电解质外渗率最低。揭示了一定剂量N+注入大豆种子可削弱幼苗脂质过氧化作用以及提高其抗寒性的关系。     

聚丙烯的辐射效应

本文研究了在室温下,真空,氮气或空气存在时,γ射线对聚丙烯毡和薄膜性能的影响(包括粘均分子量、等规度、机械强度和结晶度)。测定了辐照时产生的气体,并计算了它们的G值,分别为G_(H2)=2.52～3.56,G_(CH4)=0.11～0.21,G_(C2H4)=0.01～0.02,G_(C3H6)=0.13～0.21,G_(C4H8)=0.26～0.24 实验结果表明,剂量率在2.78×10~2rad/s时,辐照剂量小于5×10~5rad,材料性能几乎没有变化,剂量继续增加,物理和机械性能逐渐下降,辐照剂量超过5×10~6rad后,就产生大量低分子碳氢化合物,辐照剂量达到3×10~7rad时,试样受到极大破坏,甚至可成粉末。 ESR光谱测定结果指出,在真空辐照时产生的陷落自由基,一旦暴露空气就转变成过氧化自由基,并可引起自氧化降解反应,使试样进一步裂解。因此,我们认为要提高聚丙烯的辐射稳定性,可添加某些抗氧剂或做成多组份共聚物。     

N+离子束和60Coγ射线辐照引起脂质过氧化产物及调节酶活性变化的比较研究

以烟草愈伤组织中超氧化自由基（O2）、过氧化氢（H2O2）和丙二醛（MDA）及超氧岐化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）的产率和含量及活性为生物效应指标,比较研究了N＋离子束和60Coγ射线的辐照效应。结果表明：N＋离子束（E＝20keVD＝（1－6）×1015N＋／cm2）和γ射线（D＝135－315Gy）辐照烟草愈伤组织能够引起O2产率、H2O2和MDA含量的升高,并且升高的趋势随辐照剂量的增多而增加;同时也能够引起SOD、POD和CAT活性的变化,在N＋离子束D＝（1－3）×1015N＋／cm2和γ射线D＝135－180Gy辐照时,SOD、POD和CAT的活性增强,并且随辐照剂量的增多而增强。在N＋离子束D＝（3－6）×1015N＋／cm2,γ射线D＝180－315Gy辐照时,SOD、POD和CAT酶活性下降,其活性下降趋势随辐照剂量的增大而增强。讨论了N＋离子束辐照作用的特点。     

芦丁和黄芩甙在清除α-羟乙基过氧自由基过程中生成的过氧化氢的测定方法(1)

用动态吸附的方法对γ辐照芦丁和黄芩甙的空气饱和乙醇体系中产生的过氧化氢进行分离 ,测定了辐照生成的过氧化氢的G值 ,得到了与前人不同的结果 ,并分析了产生分歧的原因。提出并确立了正确的方法 :准确测定黄酮类化合物辐照体系中的过氧化氢值 ,必须先用柱色谱法将过氧化氢从辐照体系中分离出来再进行测定 ,再扣除黄酮类化合物因自氧化而产生的过氧化氢的量。采用 6 .93Gymin- 1的剂量率 ,测得 1× 10 - 3 mol·dm- 3 的芦丁和黄芩甙乙醇溶液中 ,经γ辐照后产生的过氧化氢G值分别为 5 .5± 0 .2和 7.3± 0 .2。与纯乙醇相比 ,辐照后过氧化氢的G值增加。     

环化聚苯乙炔耐γ辐照的研究

环化聚苯乙炔(简称CPBA)是一种高绝缘的特殊磁性的有机材料。它的分子构型特殊,故它既具有高浓度自由基又有高的稳定性。本文从下列三方面考察它耐γ辐照的情况。 (1)从红外光谱研究了三种不同剂量的γ射线辐照CPBA的样品,参比样品也在同样条件下进行辐照。红外光谱图表明:参比样品随着辐照剂量的增加,出现1700cm~(-1)谱带吸收强度的增加;但当γ辐照剂量从0到1.4×10~9rad时,CPBA红外光谱图形基本上未变化。因此,反映在化学结构上没有变化。故CPBA是耐γ辐照的。     

稀水溶液中氧化还原酶辐射失活和后失活及保护效应的研究Ⅱ.——稀水溶液中过氧化氢酶辐射后失活及保护效应

报道了稀水溶液中过氧化氢酶在辐射后的放置期间,其生物活性仍随放置时间不断下降的后失活作用。研究了剂量,初始酶浓度、辐照气氛、温度对过氧化氢酶辐射后失活的影响以及添加剂对酶辐射后失活的抑制作用,发现乙醇、甲酸钠和络合剂EDTA均可有效地抑制酶的辐射后失活。样品在辐照和辐照后放置过程中氧的存在与否是辐射后失活现象的关键,而水辐解的分子产物H_2O_2对诱发这一后失活现象起有重要作用。     

Evaluation of the stability of precipitated uranyl peroxide and its storage characteristics in solution

This work studied the stability of uranyl peroxide, which can be obtained as the final product of several processes to treat uranium mixture waste and uranium ore, in solution using various temperature, pH, and ionic strength conditions. The change in concentration of dissolved uranium and hydrogen peroxide from uranyl peroxide, the form of the dissolved uranium species, and the change in morphology of dissolved uranyl peroxide were investigated for 100 or more days. Uranyl peroxide was stable in distilled water at elevated temperatures, but dissolved in other solutions at temperatures higher than 40?°C; a greater amount of uranyl peroxide dissolved in more acidic conditions at elevated temperatures. Uranyl ions that dissolved from uranyl peroxide were able to be recovered as uranyl peroxide in the solution where the dissolution occurs by adding hydrogen peroxide. After the precipitation of uranyl peroxide, the uranyl concentration in the supernatant is low enough for the supernatant to be recycled or released into the environment. The morphologies of the partially dissolved uranyl peroxide and the re-precipitated uranyl peroxide from dissolved uranyl ions were different from that of the initial uranyl peroxide.     

Yield of H2O2in Gas-Liquid Phase with Pulsed DBD简

Electric discharge in water can generate a large number of oxidants such as ozone, hydrogen peroxide and hydroxyl radicals. In this paper, a non-thermal plasma processing system was established by means of pulsed dielectric barrier discharge in gas-liquid phase. The electrodes of discharge reactor were staggered. The yield of H2O2 was enhanced after discharge. The effects of discharge time, discharge voltage, frequency, initial pH value, and feed gas were investigated. The concentration of hydrogen peroxide and ozone was measured after discharge. The experimental results were fully analyzed. The chemical reaction equations in water were given as much as possible. At last, the water containing Rhodamine B was tested in this system. The degradation rate came to 94.22% in 30 min.     

Colorimetric quantification of aqueous hydrogen peroxide in the DC plasma-liquid system

The quantification of hydrogen peroxide(H_2O_2) generated in the plasma-liquid interactions is of great importance, since the H_2O_2 species is vital for the applications of the plasma-liquid system.Herein, we report on in situ quantification of the aqueous H_2O_2(H_2O_2 aq) using a colorimetric method for the DC plasma-liquid systems with liquid as either a cathode or an anode. The results show that the H_2O_2 aqyield is 8–12 times larger when the liquid acts as a cathode than when the liquid acts as an anode. The conversion rate of the gaseous OH radicals to H_2O_2 aqis 4–6 times greater in the former case. However, the concentrations of dissolved OH radicals for both liquid as cathode and anode are of the same order of tens of n M.     

Study on the leachable behavior of cation exchange resins

The amount of total organic carbon (TOC) leached from cation exchange resins (CERs) in condensate demineralizers are related to the quality of reactor water in nuclear power plants (NPPs). In the recent years, quality problems of CERs used by ChinShan and KuoSheng NPPs have been identified. Prior to use, TOC and sulfate concentrations must be reduced to meet the criteria; however, this involves an extended purification process and heavy use of water resources. Even in cases where resin can be used, the quality of the water in the reactor remains poor. This study, therefore, investigated the leachates of resins from these NPPs in order to establish a reference for the quality of deep bed CERs. Gel permeation chromatography and ion-pair chromatography were used to identify molecular peaks in the CER leachates in order to elucidate the molecular distributions. We also sought to determine TOC and sulfate concentrations of post-UV treatment using long-term soaking tests, in which the solutions used to soak resins were drained off for analysis on a daily basis. Hydrogen peroxide is employed to accelerate the aging process associated with decomposition in soaking tests to determine the stabilities of the resins.     

H2O2活化蒙脱石对溶液中U(Ⅵ)的吸附

利用H₂O₂对蒙脱石进行活化，获得了活化蒙脱石吸附材料(A_X-MMT)，采用X射线衍射(XRD)、傅里叶红外谱图(FTIR)、透射电镜(TEM)、扫描电镜(SEM)、比表面分析(BET)、表面Zeta电位分析等手段对活化样品进行了表征；采用静态批量实验法，考察了H₂O₂浓度、pH值、接触时间和共存阴阳离子对U(Ⅵ)在A_X-MMT上吸附率的影响。结果表明：活化保留了蒙脱石基础结构，其阳离子交换容量(CEC)有所减少，但层间距、比表面积、孔隙体积、表面酸位点和表面Zeta电位均有明显提升，对溶液中U(Ⅵ)的吸附性能显著增强；在最佳活性和吸附条件下(H₂O₂质量分数、pH值和接触时间分别为10%、6和24 h)，蒙脱石对U(Ⅵ)的吸附性能提升了8.5倍，吸附行为符合准二级吸附动力学模型；在共存阴阳离子的干扰下，H₂O₂活化蒙脱石能对U(Ⅵ)展现良好的吸附性能。     

Plasma activation towards oxidized nanocarbons for efficient electrochemical synthesis of hydrogen peroxide

Oxidized nanocarbons(ONCs) have been regarded as efficient electrocatalysts for H_2O_2 production. However, wet chemical procedures involving large volumes of strong acid and long synthetic time are usually needed to obtain these ONCs. Herein, a plasma activation strategy is developed as a rapid and environmentally benign approach to obtain various ONCs, including oxidized multiwalled carbon nanotubes, single-walled carbon nanotube, graphene, and super P carbon black. After a few minutes of plasma activation, oxygen-containing functional groups and defects can be effectively introduced onto the surface of nanocarbons. Enhanced electrocatalytic activity and selectivity are demonstrated by the plasma-ONCs for H_2O_2 production. Taking oxidized multiwalled carbon nanotubes as an example, high selectivity(up to 95%) and activity(0.75 V at 1 mA cm~(-2)) can be achieved in alkaline solution. Moreover, ex situ x-ray photoelectron spectroscopy and in situ Raman measurements reveal that C–O, C=O, edge defect, and sp2 basal planar defect are probably the active sites.     

H 2 O2活化蒙脱石对溶液中U(Ⅵ)的吸附

利用H₂O₂对蒙脱石进行活化,获得了活化蒙脱石吸附材料(A_X-MMT),采用X射线衍射(XRD)、傅里叶红外谱图(FTIR)、透射电镜(TEM)、扫描电镜(SEM)、比表面分析(BET)、表面Zeta电位分析等手段对活化样品进行了表征;采用静态批量实验法,考察了H₂O₂浓度、pH值、接触时间和共存阴阳离子对U(Ⅵ)在A_X-MMT上吸附率的影响。结果表明：活化保留了蒙脱石基础结构,其阳离子交换容量(CEC)有所减少,但层间距、比表面积、孔隙体积、表面酸位点和表面Zeta电位均有明显提升,对溶液中U(Ⅵ)的吸附性能显著增强;在最佳活性和吸附条件下(H₂O₂质量分数、pH值和接触时间分别为10%、6和24 h),蒙脱石对U(Ⅵ)的吸附性能提升了8.5倍,吸附行为符合准二级吸附动力学模型;在共存阴阳离子的干扰下,H₂O₂活化蒙脱石能对U(Ⅵ)展现良好的吸附性能。     

HR－1型奥氏体不锈钢氢渗透行为研究

采用超高真空气相氢渗透实验技术研究了ＨＲ－１型奥氏体不锈钢的氢渗透行为，测量了氢的扩散系数，及氢渗透率。还就试样表面氧化对其氢渗透行为的影响进行了研究，结果表明：试样表面氧化导致氢扩散系数及氢渗透率显著降低，渗透激活能增大，扩散激活能不变。     

Visualization of gold nanoparticles formation in DC plasma-liquid systems

Dual argon plasmas ignited by one direct current power source are used to treat an aqueous solution of hydrogen tetrachloroaurate-(Ⅲ) trihydrate(HAuCl_4·3H_2O) which is contained in an H-type electrochemical cell. The solution contained in one cell acts as a cathode, and in the other as an anode. Experiments are carried out to directly visualize the formation process of gold nanoparticles(AuNPs) in separated cells of the H-type electrochemical reactor. The results and analyzes suggest that hydrogen peroxide and hydrated electrons generated from the plasmaliquid interactions play the roles of reductants in the solutions, respectively. Hydrogen peroxide can be generated in the case of the liquid being a cathode or an anode, while most of hydrated electrons are formed in the case of the liquid being an anode. Therefore, the reduction of the AuCl_4~-ions is mostly attributed to the hydrogen peroxide as the liquid acts as a cathode, while to the hydrogen peroxide and hydrated electrons as the liquid acts as an anode. Moreover, the pH value of the solution can be used to tune the formation processes and the final form of the AuNPs due to its mediation of reductants.