添加剂对苯乙烯辐射聚合的影响

研究并讨论了甲醇，四氯化碳和反式二苯乙烯三种添加剂对苯乙烯辐射本体聚合反应机理的影响。实验结果表明，室温下，当添加剂浓度为１．０×１０＾０３－１．０×１０＾－１ｍｏｌ／Ｌ，剂量５５Ｇｙ／ｍｉｎ、总剂量为１０ｋＧｙ时，随着聚合体系中ＭｅＯＨ和ＣＣｌ４浓度增加，相应的Ｓｔ辐射聚合转化率谱增加，进而趋于平缓，所得聚苯乙烯分子量却随之下降。     

水溶性超高分子量聚丙烯酸胺的辐射反相乳液合成

用＾６０Ｃｏγ射线引发丙烯酰胺反相乳液聚合，研究了吸收剂、剂量率、乳化剂含量和单体含量及辐射后效应对聚丙烯酰胺分子量的影响，特别是采用高剂量率引发，特低剂量率辐射聚合的手段，不仅提高了产物分子量，缩短聚全时间，而且提高了转化率，防止了聚合物的交联。     

辐射制备缓放抗癌药氟脲嘧啶（5—Fu）及其对小鼠肿瘤的治疗作用

本文报告了甲基丙烯酸酯类在室温下进行辐射聚合制备缓放抗癌药氟脲嘧淀（５－Ｆｕ）的研究结果。药物接受１８．７２ｋＧｙ照射后其红外紫外光谱未见明显改变，说明Ａｒａ－Ｃ受１８．７２ｋＧｙ以下的辐射对其没有影响，可以用于辐射固化。肿瘤病人化疗的最大问题是毒副...     

小鼠免疫器官（胸腺、脾脏和淋巴结）成克隆基质祖细胞辐射敏感性的研究

用体外液体单层培养技术研究了小鼠胸腺、脾脏和淋巴结成克隆性基质祖细胞（ＣＦＵ－Ｆ）的辐射敏感性：胸腺ＣＦＵ－Ｆ的Ｄ０值为２．３Ｇｙ，ｎ值为１．５，脾脏为２．８Ｇｙ和１．２，雨淋巴结的则为２．７Ｇｙ及１．４。脾致密型ＣＦＵ－Ｆ亚群的Ｄ０值为２．１Ｇｙ，ｎ＝１．５；而松散型ＣＦＵ－Ｆ亚群的Ｄ０＝４．４Ｇｙ，ｎ＝１．２。这为大剂量辐射损伤混输基质细胞以提高受体免疫造血功能，提供了实验依据。     

人工核素~(137)Cs对我国陆地γ辐射剂量率的贡献

我国陆地１３７Ｃｓ沉积所造成的γ辐射剂量率,以均匀分布模式进行估算比较合理。以此得到,我国各省的１３７Ｃｓγ辐射剂量率的均值在（７—１８） ×１０－１０Ｇｙｈ－１之间,约占陆地总的γ辐射剂量率的１％－３％;考虑到人口的分布,全国的平均值约为９×１０－１０Ｇｙｈ－１,约占总γ剂量率的１．５％左右。但最高值可达 １．７ × １０－８Ｇｙｈ－１,与其它任一天然放射性核素的贡献相接近。与此相比较,如果用张弛长度为 ３ｃｍ的指数分布模式估算,１３７Ｃｓ γ辐射剂量率的贡献比用均匀分布模式约高 １倍。     

小剂量照射的淋巴细胞外液诱导其亚群细胞 DNA 合成的适应性反应

预先给予４．０ｃＧｙγ射线照射的人外周血淋巴细胞，经ＰＨＡ刺激２４ｈ后提取细胞外液，观察其对大剂量照射后受损伤的亚群细胞的影响。结果表明，ＣＤ＋８、ＣＤ＋４细胞损伤明显减轻，且损伤剂量分别为１．５、３．０Ｇｙ时，适应性反应最强。结果还显示，ＣＤ＋８细胞较ＣＤ＋４细胞对辐射更为敏感，且在１．５Ｇｙ剂量点附近，适应性反应亦更强。     

水溶性超高分子量聚丙烯酰胺的辐射反相乳液合成

用~(60)Coγ射线引发丙烯酰胺反相乳液聚合，研究了吸收剂量、剂量率、乳化剂含量和单体含量及辐射后效应对聚丙烯酰胺分子量的影响，特别是采用高剂量率引发，特低剂量率辐射聚合的手段，不仅提高了产物分子量，缩短聚合时间，而且提高了转化率，防止了聚合物的交联。     

丙烯酰胶-乙醇体系辐射反应的研究

本文介绍了在乙醇介质中用~(60)Coγ射线辐射引发聚合合成纯度较高的聚丙烯酰胺(PMA),并对它的辐射聚合动力学进行了研究。结果表明:在乙醇介质中丙烯酰胺(AM)辐射聚合转化率随着反应体系的温度、剂量率及单体浓度的增加而增加,但聚合物分子量却随着反应体系温度的增加而略有下降。此外,计算了本体系的表观活化能为7.56kJ/mol(1.88kcal/mol)。     

《癌症的遗传易感性》：ICRP79号出版物

１　背景１．１报告的产生ＩＣＲＰ第１分委员会（辐射效应）在其１９９２年９月北京会议后,就建议成立一个工作组,准备有关癌症易感性的报告,包括对放射防护的可能影响。其后主委员会接受了该建议,于是工作组从１９９３年６月开始工作。该工作组由Ｒ．Ｃｏｘ任主席,其他成员有Ｅ．Ｊ．Ｓｔａｎｂｒｉｄｇｅ,Ｃ．Ｆ．Ａｒｌｅｔｔ,Ｋ．Ｓａｎｋａｒａｎａｒａｙａｎａｎ,Ｃ．Ｅ．Ｌａｎｄ和Ｍ．Ｓ．Ｓａｓａｋｉ。报告于１９９７年５月经主委员会通过,并出版了７９号出版物。１．２背景知识在过去的２０年中,我们对癌症过程的基本…     

重离子辐射对喹乙醇的作用

研究重离子＾１２Ｃ＾６＋（１．６５６×１０＾４Ｇｙ）、＾１６Ｏ＾５＋（１．５８５×１０＾７Ｇｙ）对喹乙醇的作用，结果表明：两种重离子辐射后１５％以上的喹乙醇结构发生了改变，２６６ｎｍ，３８２ｎｍ二处特征吸收峰随其含量的下降而变平，产生多种辐射产物，重离子辐射后的喹乙醇抗菌作用明显增强。     

丙烯腈辐射聚合机理的NMR研究

用ＮＭＲ方法探讨了丙烯腈均相辐射聚合过程剂量和剂量率对聚合物的影响，以及由此引起的合物空间立体异构规整度不同，并对丙烯腈辐聚合机理进行了初步的讨论。     

PIXE investigation of in vitro release of chloramphenicol across polyvinyl alcohol/acrylamide hydrogel

Hydrogels based on polyvinyl alcohol and different amounts of acrylamide monomer were prepared by thermal cross-linking in the solid state. The hydrogels were investigated for drug delivery system applications. Chloramphenicol was adopted as a model drug to study its release behavior. Particle induced X-ray emission was utilized to study the drug release behavior across the hydrogels and a comparison study with ultraviolet measurements was performed. Fourier Transform Infrared measurements were carried out for molecular characterization. The releasing behavior of the drug exhibits a decrease and a subsequent increase in the release rate, as the acrylamide monomer increases. Characterization of the hydrogels has shown a competitive behavior between crosslinking with AAm acrylamide monomer or oligomerized version, depending on the amount added to prepare the hydrogels.     

甲基乙烯基硅泡沫材料在复合条件下的辐射效应研究

为考察甲基乙烯基硅泡沫材料在不同条件下的辐射效应,开展了受压状态下材料经⁶⁰Co γ射线辐照后的热老化和湿热老化实验。采用扫描电镜、傅里叶转换红外光谱仪、固体核磁共振仪、万能材料试验机和蠕变松弛试验机等手段剖析了材料微观结构和宏观性能。结果表明,不同条件下老化后甲基乙烯基硅泡沫材料的泡孔有减小的趋势。²⁹Si交叉极化的NMR分析发现材料中有机硅链段峰的强度随吸收剂量的增大而升高,¹³C交叉极化的NMR分析表明γ射线辐照后材料的结构规整性有所降低。辐射后热老化样品的拉伸强度总比辐射后湿热老化样品的低,辐射老化和湿热老化的协同作用对材料的应力松弛率影响非常明显。     

高分辨^13C NMR在聚合物辐射化学中的应用

综述了高分辨~(13)C核磁共振谱(~(13)C NMR)在聚合物辐射化学研究中的应用。重点介绍了用固体高分辨~(13)C NMR研究聚合物辐射交联结构途径和应用范围。     

Synthesis and properties of radiation modified thermally cured castor oil based polyurethanes

Thermally cured polyurethanes were prepared from castor oil and hexamethylene diisocyanate (HMDI). Due to the long aliphatic chain of the castor oil component of polyurethane, thermal curing of castor oil based polyurethane (COPU) is limited by increasing polymer viscosity. To enhance further crosslinking, COPUs were exposed to doses up to 3.0 MGy produced by the mixed ionizing radiation field of a SLOWPOKE-2 research nuclear reactor. The physico-mechanical properties of castor oil based polyurethanes (COPU), unirradiated and irradiated, were characterized by mechanical tensile tests. A four-fold increase in modulus and tensile strength values from 0.930 to 4.365 MPa and 0.149 to 0.747 MPa, respectively, suggests improved physico-mechanical properties resulting from radiation. The changing areas of the carbonyl and the NH absorbance peaks and the disappearance of the isocyanate peak in the FTIR spectra as radiation progressed, indicates increased hydrogen bonding and intermolecular crosslinking, which is in agreement with the mechanical tests. Unchanging ¹³C solid state NMR spectra imply limited sample degradation with increasing radiation.     

Radiation effect of Apocynum fiber

1 Introduction Apocynum fiber is known for its softness, luster, coolness, good moisture absorption, and air perme-ability. Still, it has some faults such as smooth on sur-face, less curves, and inferior quality for spinning. The physical properties of Apocynum fiber was studied by Zhang Yi et al,[1] and Ce induced graft Apocynum fiber was studied by Chen Bowen et al.[2] Hassanpour and coworkers studied the modification of the cellu-lose.[3,4] We primarily focused on the concentration and…     

碳离子束辐照选育截短侧耳素菌原生质体

使用12C6+离子束辐照Clitopilus pinsitus原生质体至不同吸收剂量,运用琼脂柱预筛和96孔板固体发酵选育截短侧耳素高产变异株。结果显示,最佳12C6+离子束吸收剂量为1.5 Gy,在该吸收剂量下正变异率为37.58%。选育出C.pin15I5E和C.pin15II6B两株正变异株,其产量较出发菌株分别提高16.17%和15.47%。表明重离子束辐照原生质体是行之有效的工业微生物诱变育种方法。     

PETP固体径迹探测器的性能研究

报道了惭烯对苯二酸醌固体核径迹探测器对裂变碎片记录性能的实验研究。在改变温度、蚀刻时间和蚀刻液浓度等条件下测量了裂变碎片迷平均直径的变化。实验结果表明：蚀綮 变化对裂变碎片径迹的影响最大，而浓度和蚀刻的影响不大。同时用低能＾１６Ｏ重离子辐照ＰＥＴＰ探测器，并得到了它的标定曲线。     

Study on chemical structures of poly (tetrafluoroethylene-co-perfluoroalkylvinylether) by soft-EB irradiation in solid and molten state

Poly (tetrafluoroethylene-co-perfluoroalkylvinylether) (PFA) was irradiated by soft electron beam (soft-EB) under nitrogen gas atmosphere in solid-state and its molten state, respectively. The changes of thermal property and chemical structures of irradiated PFA in solid-state and molten state were studied by differential scanning calorimetric analysis (DSC) and solid-state ¹⁹F magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. By DSC analysis, the melting temperature shifted to lower temperatures, and crystallinity decreased with increasing soft-EB dose. By solid-state ¹⁹F MAS NMR spectroscopy, the new signals was observed and the detected new signals in irradiated PFA at 315 °C and at 30 °C were due to the tertiary carbon group with branching site (Y-type crosslinking site), perfluoro-propylene site and chain end methylene groups, respectively.Moreover, the molar ratio of perfluoroalkylvinylether (FAVE) structure to -CF₂- units decreased with increasing dose.     

Study of density effect of large gas cluster impact by molecular dynamics simulations

Large gas cluster impacts cause unique surface modification effects because a large number of target atoms are moved simultaneously due to high-density particle collisions between cluster and surface atoms. Molecular dynamics (MD) simulations of large gas cluster impacts on solid targets were carried out in order to investigate the effect of high-density irradiation with a cluster ion beam from the viewpoint of crater formation and sputtering. An Ar cluster with the size of 2000 was accelerated with 20 keV (10 eV for each constituent atom) and irradiated on a Si(1 0 0) solid target consisting of 2 000 000 atoms. The radius of the Ar cluster was scaled by ranging from 2.3 nm (corresponding to the solid state of Ar) to 9.2 nm (64× lower density than solid state). When the Ar cluster was as dense as solid state, the incident cluster penetrated the target surface and generated crater-like damage. On the other hand, as the cluster radius increased and the irradiation particle density decreased, the depth of crater caused by cluster impact was reduced. MD results also revealed that crater depth was mainly dominated by the horizontal scaling rather than vertical scaling. A high sputtering yield of more than several tens of Si atoms per impact was observed with clusters of 4-20× lower volume density than solid state.