辐射PVDF／PEA共混物的熔融与结晶行为研究

ＰＶＤＦ／ＰＥＡ共混物熔融后在冰水中淬火或自然冷却，制得两种没结晶度的试样，经电子束辐照后，用示差热分析等方法研究它们熔融与结晶行为。结果表明，自然冷却试样的熔点Ｔｍ和结晶温度ＴＣ随辐照剂量的增加而降低，而熔融热焓ΔＨｆ，结晶度ＸＣ和结晶热焓ΔＨＣ随辐照剂量的增加先增加后降低。     

HALS及抗氧剂对聚丙烯辐射致色的影响

研究了在辐照条件下受阻胺光稳定剂（ＨＡＬＳ）、各种抗氧剂及ＨＡＬＳ与抗氧剂并用等对聚丙烯（ＰＰ）的黄度（ＹＩ）的影响。实验发现,添加五甲基ＨＡＬＳ的聚丙烯的黄度均小于添加相应的四甲基ＨＡＬＳ的聚丙烯的黄度。当抗氧剂Ｉｒｇａｎｏｘ１０７６和ＰＤＳ并用时,聚丙烯的黄度比单独添加１０７６或ＰＤＳ的聚丙烯的黄度都低。单独添加１０７６的聚丙烯的黄度比添加抗氧剂Ｉｒｇａｆｏｓ１６８或ＩｒｇａｎｏｘＰＳ－８０２的聚丙烯的黄度都小。当ＰＤＳ和Ｉｒｇａｎｏｘ１０７６并用时聚丙烯的黄度小于ＰＤＳ和Ｉｒｇａｆｏｓ１６８或ＩｒｇａｎｏｘＰＳ－８０２并用时的黄度。辐照后聚丙烯的黄度开始随放置时间很快降低,但随时间增加,黄度的变化逐渐减慢,最后基本保持不变。对结果进行了分析和讨论。     

加速器电磁元件设计微机软件库的初步研制

描述了加速器电磁元件设计的微机软件库初步研制工作，包括ＰＯＩＳＳＯＮ／ＳＵＰＥＲＦＩＳＨ、ＲＥ－ＬＡＸ３Ｄ、ＴＲＡＮＳＰＯＲＴ、ＲＡＹＴＲＡＣＥ、ＭＡＤ、ＰＡＲＭＥＬＡ系统软件和软件包括移植、开发、以及自行开发的软件ＤＥ２Ｄ、ＤＥ３Ｄ、ＣＹＣＣＡＥ、ＣＹＣＣＥＮ的整理工作。介绍了这些软件在一定实际工程中的应用情况。     

电子束辐照聚碳硅烷热解合成SiC陶瓷材料Ⅱ.低分子量聚丁二烯对不熔化反应的敏化效应

通 过溶液共 混的方法 将低分 子量聚丁 二烯（ Ｌ Ｍ Ｗ Ｐ Ｂ） 加 入聚碳硅 烷（ Ｐ Ｃ Ｓ） 中,用直 线加速器产 生的能 量为９０ Ｍｅ Ｖ 的电 子束 在 Ｈｅ 气氛 中 辐照, 然后 在 高温 下 热解 转 化为 Ｓｉ Ｃ 陶 瓷。结果表明 ：添加４８ ｗｔ ％ 的 Ｌ Ｍ Ｗ Ｐ Ｂ 即 能够有效 地将 Ｐ Ｃ Ｓ 的凝胶 化剂 量从 ５ Ｍ Ｇｙ 降 低至 ～０４ Ｍ Ｇｙ 。加有 Ｌ Ｍ Ｗ Ｐ Ｂ 的 Ｐ Ｃ Ｓ,其 辐照产物 的富里衰 变换红 外光谱（ Ｆ Ｔ Ｉ Ｒ） 谱 与不含 Ｌ Ｍ Ｗ Ｐ Ｂ 者相 似。用气相色谱 法检测到 辐照过 程中有 Ｈ２ 和 Ｃ Ｈ４ 析出 。 Ｌ Ｍ Ｗ Ｐ Ｂ 对 辐照 产物 的 热解 反 应无 明显 影 响,用热重红外光 谱（ Ｔ Ｇ Ｆ Ｔ Ｉ Ｒ） 联 用技术 和气相色 谱法 检 测到 热解 过 程中 同样 有 Ｃ Ｈ４ 和 大量 的 Ｈ２ 析出。在 Ｎ２ 气流中 ,将辐照 后的 Ｐ Ｃ Ｓ／ Ｌ Ｍ Ｗ Ｐ Ｂ 试样 升温 至 １２００ ‘ Ｃ,热 解 后得 到有 金 属光 泽 的 黑色产物, Ｘ 射线 衍射谱图 与元素 分析结果 表明该产 物为高 纯度的半 晶 Ｓｉ Ｃ 陶瓷 。     

超高分子量聚乙烯的辐照效应

通过密度测定和ＤＳＣ热分析，观测了超高分子量聚乙烯的辐射效应。实验结果表明：在吸收剂量０—１．１３ＭＧｙ范围内，密度随吸收剂量的增加而增大，熔化热和熔点也有所增加，特别是在低剂量范围内增加十分明显。以上结果都说明，超高分子量聚乙烯在辐照过程中，结晶在完善或有新的结晶形成     

γ辐照及热处理对拉伸高密度聚乙烯结晶度的影响

研究了在真空和空气中γ辐照对拉伸高密度聚乙烯结晶度的影响。结果表明：真空中辐照约２５０ｋＧｙ吸收剂量，拉伸ＨＤＰＥ的结晶随吸附剂量的增加而降低，然后吸收剂量的增加对其结晶度基本上无影响；而在空气中辐照至１０００ｋＧｙ的吸收剂量，拉伸ＨＤＰＥ的结晶度基本保持不变同时还研究了不同温度热处理对未辐照拉伸ＨＤＰＥ的结晶度影响，其结晶度首先随热处理温度的增加而迅速增加，约１２０℃时达到极大值。     

稳压器排放系统应力分析评定和管道支撑布置

介绍了泰山核电二期工程稳压器排放系统应力分析评定和管道布置及支撑调整过程，即采用ＰＤＬ－ＳＹＳＰＩＰＥ ＩＮＴＥＲＦＡＣＥ接口软件在三维ＣＡＤ工程设计系统ＰＤＬ中截取系统的各种特性参数，并将这些特性参数作为专用管道系统应力分析程序ＳＹＳＰＩＰＥ计算输入，在此基础上，利用ＳＹＳＰＩＰＥ程序的快速应力分析功能调整管道布置、支撑布置和支撑类型，并对管道承受的自重、内压、热膨胀、地震、破管和超压排放等载荷     

THINDOWN IN RADIOBIOLOGY：E．COLI B／r，Bs－1，B．SUBTILUS SPORES，AND V－79 CHINESE HAMSTER CELLS

ＴＨＩＮＤＯＷＮＩＮＲＡＤＩＯＢＩＯＬＯＧＹ：Ｅ．ＣＯＬＩＢ／ｒ，Ｂｓ－１，Ｂ．ＳＵＢＴＩＬＵＳＳＰＯＲＥＳ，ＡＮＤＶ－７９ＣＨＩＮＥＳＥＨＡＭＳＴＥＲＣＥＬＬＳＺｈａｎｇＣｈｕｎｘｉａｎｇ（张纯祥）（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓＺｈｏｎｇ...     

DHDECMP-TBP/煤油对U(Ⅵ)的萃取

ＤＨＤＥＣＭＰ－ＴＢＰ／煤油体系从１．０ｍｏｌ／Ｌ ＨＮＯ３－ＵＯ２（ＮＯ３）２介质中萃取Ｕ（Ⅵ），除了存在ＴＢＰ和ＤＨＤＥＣＭＰ的单独萃取反应外，还存在着ＤＨＤＥＣＭＰ－ＴＢＰ的协同萃取反应。形成的萃合物分别为ＵＯ２（ＮＯ３）２．２ＴＢＰ、ＵＯ２（ＮＯ３）２．２ＤＨＥＣＭＰ和ＵＯ２（ＮＯ３）２．ＤＨＤＥＣＭＰ．ＴＢＰ。实验测定了ＴＢＰ／煤油、ＤＨＤＥＣＭＰ／煤油和ＤＨＤＥＣＭＰ－ＴＢＰ／煤国同萃     

辐射交联CB／EVA导电复合热氧稳定研究

导电ＣＢ／ＥＶＡ半导电聚合物复合电阻的热氧稳定性与辐照剂量的关系，并对辐射照样品作了ＤＳＣ，ＩＲ等分析。结果表明，合适的辐照剂量和复合热氧稳定剂体系参有效地提高半导电ＣＢ／ＥＶＡ复合物电阻的热氧稳定性。     

Thermal characterization of the HDPE/LDPE blend (10/90) irradiated using γ-rays

Gamma irradiation effect over the properties of slow cooled and fast cooled HDPE/LDPE 10/90 blend was studied. The blend and the neat polyethylenes were irradiated at room temperature in the presence of air using the following doses (4.8 kGy/h): 0, 50, 150, 400 and 1000 kGy. Differential scanning calorimetry (DSC) experiments were carried out using the following heating rates: 5, 10 and 20 °C/min. DSC results for the slow and fast cooled blend showed traces with three melting peaks and with increasing irradiation dose two melting peaks were obtained, i.e. the high melting peak shifts toward lower temperatures to merge with the intermediate melting peak into one endotherm. No changes in crystal structure by X-ray diffraction were found as a result of samples irradiation. Radiation crosslinking prevents crystal rearrangements during heating in the DSC. Gel content and melt flow index (MFI) measurements showed that radiation induced a high degree of crosslinking for all samples; gel content values were above 50% and a drop of more than 90% in the MFI was found. Irradiation of slow cooled samples resulted in larger values of gel content and lower MFI values than for fast cooled samples, mainly because of the higher degree of crosslinking for the former.     

Microstructural evolution of the China Low Activation Martensitic (CLAM) steel irradiated by H and He ion beams

China Low Activation Martensitic (CLAM) steel was irradiated at room temperature with different doses of He⁺ and H⁺ ion beams. TEM indicated that the microstructure of unirradiated CLAM steel consisted of laths, grain boundaries, dislocations and carbides. Electron diffraction patterns revealed that the microstructure of carbides at grain boundaries was primarily dominated by M₂₃C₆ carbide. Vacancy clusters were induced into the matrix after irradiation. TEM-EDX of carbides and matrices of unirradiated and post-irradiated samples were performed to investigate the composition of carbides and the effect of irradiation on the composition of carbides. Carbides from unirradiated and irradiated specimens at grain boundaries were found to be enriched with Cr. For irradiated specimens, concentrations of Cr increased as the irradiation dose was increased. Cr enrichment could lead to precipitation of additional phase.     

Neutron irradiation studies on low density pan fiber based carbon/carbon composites

Carbon has been extensively used in nuclear reactors and there has been growing interest to develop carbon-based materials for high-temperature nuclear and fusion reactors. Carbon-carbon composite materials as against conventional graphite material are now being looked into as the promising materials for the high temperature reactor due their ability to have high thermal conductivity and high thermal resistance. Research on the development of such materials and their irradiation stability studies are scant. In the present investigations carbon-carbon composite has been developed using polyacrylonitrile (PAN) fiber. Two samples denoted as Sample-1 and Sample-2 have been prepared by impregnation using phenolic resin at pressure of 30 bar for time duration 10 h and 20 h respectively, and they have been irradiated by neutrons. The samples were irradiated in a flux of 10¹² n/cm²/s at temperature of 40 °C. The fluence was 2.52 × 10¹⁶ n/cm². These samples have been characterized by XRD and Raman spectroscopy before and after neutron irradiation. DSC studies have also been carried out to quantify the stored energy release behavior due to irradiation. The XRD analysis of the irradiated and unirradiated samples indicates that the irradiated samples show the tendency to get ordered structure, which was inferred from the Raman spectroscopy. The stored energy with respect to the fluence level was obtained from the DSC. The stored energy from these carbon composites is very less compared to irradiated graphite under ambient conditions.     

辐射交联对LDPE/CB复合物PTC效应稳定性的影响

研究了低密度聚乙烯（LDPE）／炭黑（CB）复合物在升温、降温循环中的导电性能。利用示差扫描量热分析仪（DSC）研究了复合物的熔融行为，以及应用压力－体积－温度分析仪（PVT）研究了复合在聚合物熔点时的体积膨胀性能。结果表明，辐射交联可以有效地提高复合物正温度系数（PTC）效应的重复性，纯凝胶复合物的PTC强度显著降低，说明溶胶在聚乙烯熔点时的体积膨胀是交联复合物正温度系数（PTC）效应的产生的重要原因。     

Identification of radiation treatment of wheat （Triticum aestivum. L）and rice （Oryza sativa. L） samples using thermoluminescence of contaminating minerals

Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of food. Because of the rapid commercialization of irradiated foods throughout the world, compliance of different regulations relating to use of technology in different countries and demand of consumers for clear labelling of irradiated foods, there is need for the development of analytical methods to detect radiation treatment of food. Among several methods studied so far, thermoluminescence （TL） is an important method that can be used to find out the irradiation history of food that contain even a very minute amount of dust particles. In this study, the irradiated and unirradiated wheat and rice samples were analyzed using the TL method. The samples were purchased from the local market of Peshawar and irradiated to radiation doses of 0.5 and 1.0 kGy using Co-60 gamma irradiator at the Nuclear Institute for Food and Agriculture （NIFA）, Peshawar. The mineral contaminants were isolated by jet water, ultrasonic treatment, and density gradient. TL glow curves of the isolated minerals from irradiated and unirradiated samples were recorded between the temperature ranges of 50-500℃ using a TL reader. Generally, the glow curves for irradiated samples showed much higher TL intensities （TL1） than the unirradiated samples. The results were normalized by rerradiation of mineral samples to gamma-ray dose of 1.0 kGy followed by determination of the second glow curves （TL2）. The ratio of the area of first glow curve to that of second glow curve （TL1/TL2） was calculated for selected temperature intervals and compared with the recommended values for unirradiated and irradiated samples. Finally, the shapes of the glow curves for irradiated and unirradiated samples were also analyzed. On the basis of these results （comparison of TL-intensities, TL1/TL2 ratios and shapes of the glow curves）, all the irradiated and unirradiated samples of wheat and rice were unequivocally identified.     

DSC studies of retrogradation and amylose-lipid complex transition taking place in gamma irradiated wheat starch

The effect of gamma irradiation (⁶⁰Co) with doses of 5-30 kGy on the amylose-lipid complex transition and retrogradation occurring in gels containing ca. 50% and ca. 20% wheat starch was studied by differential scanning calorimetry (DSC) during heating-cooling-heating cycles (up to three cycles). Transition of the amylose-lipid complex occurs in all the irradiated samples at a lower temperature as compared to the non-irradiated starch. That effect was larger when the radiation dose was higher. A further thermal treatment causes a decrease of the transition temperature in the irradiated samples, with no effect or increase of that temperature observed for the non-irradiated ones. Irradiation hinders retrogradation taking place in 50% gels but facilitates the process occurring in 20% gels. The differences between the irradiated and the non-irradiated samples are more evident in the every next heating or cooling cycle as well as after storage and in the case of ca. 50% suspensions as compared to ca. 20% suspensions. The results point out to the deterioration of the structure of the complexes formed in the irradiated starch as compared to the non-irradiated one.     

The terminal solid solubility of hydrogen in irradiated Zircaloy-2 and microscopic modeling of hydride behavior

Differential scanning calorimetry (DSC) has been applied to elucidate the terminal solid solubility (TSS) of hydrogen in Zircaloy-2 cladding tubes and spacer bands irradiated in commercial BWRs. While recovery of irradiation defects during the first heating stage of as-irradiated specimens made the DSC peak of hydride dissolution dull or broader, no significant difference was detected in the TSS between unirradiated and irradiated Zircaloy-2, irrespective of fast neutron fluence. The effect of post-irradiation annealing on TSS was also examined. The results suggest almost no interaction between irradiation defects and dissolved hydrogen or hydrides at temperatures around 300 °C. Using the present TSS data and reported hydrogen- and hydride-related properties, a microscopic analysis code HYMAC for analyzing hydride behavior in cladding tube with textured grains was constructed. Stress-induced preferential precipitation and dissolution of hydrides were reproduced by adopting a TSS sub-model in which the solubilities decrease in proportion to stress normal to the habit plane in grains and to grain faces. Analyzed results by the code were consistent with typical experimental results of hydride behavior.     

Radiation-induced branching and crosslinking of poly(tetrafluoroethylene) (PTFE)

The effect of electron beams on poly(tetrafluoroethylene) (PTFE) at elevated temperatures above the melting point on oxygen-free conditions has been studied using differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS), Fourier-transform infrared (FTIR) spectroscopy, thermo-gravimetric analysis (TGA) and tensile test. The investigations have shown that the chemical structure and several properties of PTFE are greatly altered by the irradiation. DSC and WAXS indicate that the crystallinity of the PTFE irradiated with high doses is reduced. CF₃ side groups and branched structures are assumed to hinder the crystallization. TGA has shown that the thermal stability of the radiation-modified PTFE is considerably lower than that of unirradiated PTFE.     

Elevated-temperature tensile properties of irradiated 9 Cr-1 MoVNb steel

Normalized-and-tempered 9 Cr-1 MoVNb steel tensile specimens were irradiated in the Experimental Breeder Reactor-11 (EBR-11) at 390, 450, 500, and 550°C to ～2.1 and 2.5 × 10²⁶ neutrons/m² (> 0.1 MeV), which produced displacement damage levels of ～10 and 12 dpa, respectively. Tensile tests were conducted at the irradiation temperature and at room temperature. In addition to the irradiated specimens, as-heat-treated specimens and as-heat-treated specimens thermally aged at the irradiation for 5000 h were also tested.Thermal aging had no effect on the unirradiated tensile properties. Irradiation at 390°C increased the 0.2% yield stress and the ultimate tensile strength above those of the unirradiated control specimens. The ductility decreased slightly. After irradiation at 450, 500, and 550°C, the tensile properties were essentially the same as the unirradiated values. The hardening at 390°C was attributed to the dislocation and precipitate structure formed during the irradiation. The lack of hardening at 450°C and higher correlates with an absence of an irradiation-induced damage structure.     

Effect of prestrain at 77 K on the plastic deformation of Zircaloy - 2

The tensile properties of unirradiated and neutron-irradiated Zircaloy-2 specimens have been studied after a pre-straining treatment at 77 K. The prestrain was found to increase the rate of work hardening and the uniform and total elongations of unirradiated transverse specimens, as observed by Reed-Hill and Dahlberg in the case of zirconium. Prestrain at 77 K had a small effect on the stress-strain behaviour of irradiated specimens. Metallographic examination showed extensive 11$\text{2}$1-twinning in all pre-strained specimens.