对硝基苯胺的辐照降解研究

采用电子束辐照对硝基苯胺水溶液,研究了对硝基苯胺的辐照降解过程,并对吸收剂量、初始浓度、溶液pH及H202加入等因素对辐照降解效果的影响进行了探讨。结果表明,电子束辐照能够有效地降解对硝基苯胺。初始浓度为100mg／L,吸收剂量为20kGy时,对硝基苯胺的降解率可达95％以上,化学需氧量（Chemical oxygen demand,COD）的去除率可达41％以上。     

EB degradation of perfluorooctanoic acid and perfluorooctane sulfonate in aqueous solution

Electron beam (EB) degradation of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in aqueous solutions was studied.It suggested that PFOA and PFOS degradation followed the pseudo-firstorder kinetics,and degradation rates increased with increasing initial pH.Radical scavengers' experiments indicated that hydrated electron and hydrogen radical were important in the electron beam degradation of PFOA and PFOS,especially hydrated electron.The decomposition efficiencies were 95.7％ for PFOA and 85.9％ for PFOS,by EB irradiation in an anoxic alkaline solution (pH =13).The potential degradation pathways of PFOA and PFOS by electron beam irradiation through defluorination and the removal of CH2 unit were proposed.     

Spectroscopic analysis and mechanical properties of electron beam irradiated polypropylene/epoxidized natural rubber (PP/ENR) polymer blends

Polymer blends based on different ratios of polypropylene (PP) and epoxidized natural rubber (ENR) were prepared by melt extrusion into sheets. The PP/ENR blends were exposed to various dose of accelerated electrons. The formation of free radicals during and after electron beam irradiation was illustrated by electron spin resonance (ESR). Also, the effect of electron beam irradiation on the mechanical and structural morphology was investigated by stress-strain behavior and scanning electron microscope (SEM). The ESR spectra indicated the formation of alkyl and allyl radicals during electron beam irradiation and peroxyl radicals during the post effect. The rate of radical decay was found to be second-order kinetics. The improvement in mechanical properties and structural morphology was confirmed to be due to the effect of electron beam irradiation.     

电子束辐照对多酚氧化酶活性及结构的影响

应用圆二色谱及SDS-PAGE技术分析电子束辐照对多酚氧化酶(Polyphenol oxidase,PPO)活性及结构的影响。结果发现:电子束辐照可在一定程度上降低PPO酶活性;圆二色谱分析发现电子束辐照处理后,PPO酶蛋白质二级结构相对含量发生改变,但a螺旋、b折叠和b转角总含量在吸收剂量4.83 kGy时总量变化不大,当吸收剂量4.83 kGy时,随着剂量的增加含量不断下降,无规则卷曲呈上升趋势。SDS-PAGE电泳实验结果表明,辐照处理下PPO酶同时发生交联和降解反应。上述结果提示电子束辐照对PPO酶活性有一定的抑制作用。     

电子束注入PMMA空间电荷分布的Monte-Carlo模拟与实验验证

精确控制和测量电子束注入样品后电荷量以及电荷的沉积分布,对于进行高压电力电缆材料的击穿以及航空器受到高能宇宙射线破坏的研究有着非常重要的意义。本工作结合空间电荷对固体电介质材料击穿影响的研究课题,利用Monte-Carlo方法模拟计算了电子束注入聚甲基丙烯酸甲脂(PMMA)样品中电荷的沉积分布,并通过激光感应压力波法(LIPP)对电子束注入后的PMMA进行测量;实验验证计算结果,吻合较好,为以后实验参数的设计提供了重要依据。     

Electron irradiation of polyurethane: Some FTIR results and a comparison with a EGS4 simulation

In this paper, investigations have been carried out on electron beam irradiated thermoplastic and aromatic polyurethane (PU). The changes in chemical structure after irradiation were determined using FTIR spectroscopy. This study has allowed us to highlight polymer degradation versus depth and dose by following the decrease in the NH-bond intensity. The PU oxidation was also studied by following the appearance of OH bonds. Results showed that degradation and oxidation of the PU reaches a maximum between 150 and 250 μm. These effects are quantifiable up to 500 μm. Experimental results were compared with the distribution of the energy deposition simulated by the EGS4-PRESTA code. Our experimental results are in strong accordance with the simulation.     

TC4钛合金焊后电子束局部热处理及焊接残余应力测试研究

针对TC4钛合金通过电子束焊后局部热处理工艺来改善接头的性能,采用X射线法对电子束局部热处理后焊接残余应力的分布趋势进行了测试研究.试验结果表明:经电子束局部热处理后,TC4钛合金焊缝区马氏体晶粒组织得到细化;同时上表面接头残余应力的分布得到改善.     

Orientation dependence of near-threshold damage production by electron irradiation of 4H SiC and diamond and outward migration of defects

Low temperature photoluminescence measurements have been made on samples of 4H SiC and diamond irradiated in different crystallographic directions with electrons having energies close to the atomic displacement thresholds. The defects produced in the 4H SiC are found to show some differences from those predicted by molecular dynamics calculations and possible reasons for the differences are discussed. The discussion refers to results from earlier as well as new experiments on the outward migration of defects during irradiation. The results for the energy dependence of the damage introduced into <1 0 0>, <1 1 0> and <1 1 1> oriented diamond are evaluated and shown to be consistent with theory.     

The effect of the electron irradiation on the series resistance of Au/Ni/6H-SiC and Au/Ni/4H-SiC Schottky contacts

The effect of electron irradiation on Au/Ni/6H-SiC and Au/Ni/4H-SiC Schottky contacts has been studied by current voltage (I-V) characterization at room temperature. The diodes have been subjected to the electron irradiation at various energies (6, 12 and 15 MeV) and influence of the electron irradiation on the diode parameters such as barrier height, ideality factor, and series resistance has been studied. Cheung functions, Norde model and conductance method have been used to determine the diode parameters. The ideality factor of the diodes is greater than unity indicating activation of some other current transport mechanism(s). The series resistances of the diodes increase by increasing electron energy. The reverse current increases for the Au/Ni/6H-SiC diode after each electron irradiation experiment, while decreasing trend is observed for Au/Ni/4H-SiC diode. Decrease in the barrier height of Au/Ni/4H-SiC diode is observed and mainly attributed to the increase of the reverse current, while the decrease of the forward current is caused by increase in series resistance, for high electron irradiation energies.     

电子束辐射预硫化天然橡胶/丁苯橡胶并用体系的研究

以天然橡胶,丁苯橡胶(Natural rubber/styrene butadiene rubber,NR/SBR)并用体系为基材,采用电子束辐照技术对其进行辐射预硫化,研究了不同吸收剂量下,材料交联度、硫化速度及格林强度的变化趋势,并评价了电子束辐射预硫化对材料最终力学性能的影响.结果表明:NR/SBR并用体系的交联度和格林强度随吸收剂量的增加而提高,热硫化速度基本不受吸收剂量的影响,可实现删SBR并用体系的辐射预硫化;辐射预硫化与未辐射预硫化的NR/SBR相比,完全硫化后材料的力学性能相差不大.     

苯胺类污染物的电子束辐照降解研究

苯胺及其衍生物是一类主要的环境污染物，许多已被我国及欧洲国家列为优先污染物。本工作研究了苯胺、对硝基苯胺和间氯苯胺水溶液的电子束辐照降解过程。三种溶液初始浓度均为0．5mmol／L，其辐照前后稀释五倍的紫外可见吸收光谱表明，苯胺在230nin的吸收峰，对硝基苯胺在380nm的吸收峰，以及间氯苯胺在236nm的吸收峰，均随辐照吸收剂量的增加而逐渐降低。辐照吸收剂量为23kGy时，     

电子束辐照接枝对棉织物抗皱/拒水拒油性能的影响

利用MG-6600型拒水拒油剂以及柠檬酸抗皱剂,以轧烘焙、电子束辐照接枝、等离子体预处理-电子束辐照接枝三种工艺对棉织物进行后整理。傅里叶红外光谱(FTIR)证明拒水拒油剂与柠檬酸已成功接枝于棉纤维上;扫描电子显微镜(SEM)分析表明经三种工艺整理后的棉织物表面均有一层覆盖物,且经等离子预处理后的织物表面出现纵向条纹。通过测量棉织物折皱回复角(WRA)、对水的接触角(WCA)、对油(正十六烷)的接触角(OCA)大小来表征织物性能的变化。结果表明,在等离子体预处理-电子束辐照接枝工艺条件下,棉织物的抗皱、拒水、拒油性能达到最优,其WRA为185.9°,WCA为158.9°,OCA为129.1°,断裂强力、白度值均能满足服用要求,同时棉织物的耐水洗性能大大提高。     

辐射硫化丁腈橡胶拉伸强度的模糊减法聚类模型应用研究

利用模糊减法聚类构建了丁腈橡胶乳液辐射硫化后的拉伸强度预测模型,并将辨识模型与实验数据进行对比,通过检验数据来检验模糊模型的可靠性。模型预测值与实验值相关性为0.8222,由此可知模糊辨识方法建模精度高,计算量小,用此模型来分析丁腈橡胶乳液辐射硫化后拉伸强度的变化规律非常直观方便。这为材料应用模糊建模方法分析开辟了新思路。     

PVA和PEG对电子束辐照制备的Fe3O4纳米粒子的影响

常温常压下不加入任何催化剂，用两种不同的活性剂聚乙烯醇（Polyvinyl alcohol，PVA）和聚乙二醇（Polyethylene glycol，PEG），在水溶液中通过电子束辐照可以成功地制备纳米Fe3O4粒子。通过紫外可见光分光光度计（Ultraviolet-visible spectrophotometer，UV）、X射线衍射（x-ray diffraction）、透射电子显微镜（Transmission electron microscopy，TEM）对辐照后的样品的光学特性、结构、形貌、大小进行表征。发现不同的活性剂对纳米粒子的尺寸会产生影响。     

强流脉冲电子束辐照对铝薄膜的结构和性能影响

用多弧离子镀方法在DZA镍基合金基体上沉积3μm厚Al膜,用强流脉冲电子束辐照处理,加速电压为27 kV,束流密度为1.5 J/cm2,脉冲数为1次、5次和10次.SEM表面分析显示,脉冲处理后薄膜表面平整度随脉冲次数增加,但10次脉冲处理后有明显的微裂纹.电子束处理后有熔坑和喷发现象,5次脉冲处理后喷发现象最明显.截面的EPMA分析显示,电子束处理使Al膜与基体问混合.掠入射XRD分析表明,随着脉冲次数增加,Al含量减少,基体Ni含量增加,1次脉冲处理有非晶成份出现,多次脉冲处理后有NiAI新相出现,有利于薄膜耐腐蚀性能的提高.电子束辐照Al膜的耐腐蚀性能明显提高,自腐蚀电位提高约70%.     

快速响应PNIPA／Fe3O4复合凝胶辐射制备与性能研究

采用化学共沉淀法制备了四氧化三铁粒子,以N-异丙基丙烯酰胺（NIPA）、N,N-亚甲基双丙烯酰胺（MBA）和聚乙二醇（PEG）为原料,以60Coγ,射线为放射源,辐照聚合制备了多孔PNIPA／Fe3O4复合水凝胶,并对其温度敏感性、平衡溶胀率进行了表征。研究发现：磁性四氧化三铁纳米粒子在凝胶中分散均匀;凝胶具有明显的温度敏感性;致孔剂的添加提高了水凝胶的平衡溶胀率,多孔复合水凝胶失水率达96％,比普通磁性水凝胶失水率提高了约76％;致孔剂的添加使复合凝胶的最低临界相转变温度由34℃升高至37℃左右。