Improvement of the surface of polyethylene foamed sheet by irradiation

The manufacturing methods of cross-linked polyethylene foams are classified into two categories based on a type of cross-linking. One is chemical cross-linking by using peroxide as a cross-linking agent. The other method is cross-linking by irradiation. As for chemical cross-linking, a fairly thick foam sheet can be produced, and a comparatively high degree of cross-linking can be achieved. This means chemical cross-linking excels in thermo-forming but, due to a rough surface, the product is lacking in adhesive property and printability. We studied how to improve the surface condition of foam sheet without damaging the features proceeding from chemical cross-linking. As a result, it has been revealed that at the pre-stage of foaming, and by irradiating the surface at low voltage, the resultant foamed sheet with smooth surfaces and excelling in mechanical properties can be produced.     

辐射交联制备改性CMC水凝胶的溶胀行为研究

利用丙烯酰胺 (AAm)接枝改性纤维素 ,然后进行羧甲基化反应得到高取代度的丙烯酰胺 羧甲基纤维素钠 (AAm CMC Na) .对该材料进行γ射线辐照制备出新型改性CMC水凝胶 .研究了这种水凝胶的溶胀动力学、交联动力学以及温度、pH值和无机盐浓度对水凝胶溶胀行为的影响 ,并与CMC Na水凝胶进行了比较 .结果表明 ,该水凝胶和CMC Na水凝胶相比 ,优点在于辐照交联所用的剂量下降 ,而且所需的CMC浓度减少 .AAm CMC Na水凝胶的溶胀度随温度升高而增大 ,在pH为 6～ 8范围内达到最大值 ,并随无机盐浓度与吸收剂量增加而下降 ,表现出较好的温度敏感性和pH敏感性 ,可望作为吸水材料和水保持剂     

聚2,6—萘二甲酸乙二醇酯驻极体的研究

实验观察到双轴拉伸聚2,6-萘二甲酸乙二醇酯(PEN)的γ-辐射诱导我流子品种转变现象,检测到发生转变的剂量范围,在γ-辐射诱导陷阱变浅的实验基础上讨论了载流子品种转变的实质,研究了非晶及双拉PEN热驻极体在γ-辐射激励下电荷储存、迁移机理及解驻极效应。     

Novel analogues of ascomycin with modifications in the amino acid unit through photochemistry: the synthesis of 5,6-dehydroascomycin, SDZ ASQ 871

Irradiation of ascomycin 1a and its derivatives in MeOH, EtOH and propanol resulted in alkoxylation of the pipecolic acid moiety in the ε-position with concomitant reduction in the tricarbonyl region leading to 6-alkoxy-9-hydroxy derivatives in high stereoselectivities and good yields. The products, after reoxidation of the C(9)-OH, afforded the 6-alkoxy analogues of the parent compounds. Elimination of MeOH from the photoproducts, followed by oxidation gave the corresponding 5,6-dehydro amino acid analogues. Similarly, starting from the proline analogue 7 modifications in the pyrrolidine moiety could be achieved.     

微波辐照对无线电引信的影响与作用机理

 选择某型集成电路无线电近炸引信,从勤务处理状态和工作状态两方面,研究了无线电引信的微波辐照效应,确定了被试无线电引信的微波辐照损伤阈值范围在140~150 kW/cm²之间,误炸阈值在100 kW/cm²左右。微波辐照通过前门耦合导致无线电引信的高频振荡管和低频组件产生硬损伤,通过直接作用于起爆执行电路使处于工作状态的无线电引信出现误炸。     

黄玉的光谱研究

首次采用傅里叶变换红外光谱仪（ＦＴＩＲ）及镜面反射附件,对天然宝石材料－黄玉在反应堆辐照致色（成为蓝色）前后的样品进行了分析、中红外区的光谱分析,并使用ＦＴ－Ｒａｍａｎ光谱进行补充。     

Automatic control system design for an irradiation processing station on an industrial production scale

This paper discusses the characteristics of the large-sized irradiation processing process in industrial production scale, its control requirements, the principle of control system design and the implementation scheme.     

Radiolysis of oxalic and citric acids using gamma rays and accelerated electrons

The radiation technique was tested as a method for degradation of organic complexants in spent decontamination solutions. Aqueous solutions containing oxalic and/or citric acid were irradiated under different conditions. Kinetics of radiolysis of both acids was studied; the effects of various parameters, presence of inorganic ions and saturation by various gases on their degradation were investigated. Results show that irradiation leads to a sufficient degree of removal of both acids from the solution.     

激光经瞳热疗的功率选择

为了避免激光经瞳热疗带来的热损伤或治疗不足,建立了眼底层状模型并采用二维有限元法求解生物传热方程,从理论上分析了激光引起的视网膜和脉络膜的温度变化.在相同光斑条件下最高温升与照射功率成正比、与眼睛透射率成反比,可从任意功率出发计算达到阈值温升所需要的功率.在此基础上提出了照射功率与光斑直径、眼睛透射率和阈值温升的定量关系,根据此关系式得到的功率使得阈值温升在光斑直径变化时保持不变.     

Displacement damage and transmutations in metals under neutron and proton irradiation

The knowledge of the defect and impurity generation rates, as well as the defect spatial distribution, is the corner stone for the understanding of the evolution of material properties under irradiation. This knowledge is also an essential element for comprehensive experimental simulations of the behavior of irradiated materials.In this article the interaction of neutron and proton irradiation with metals is discussed with respect to displacement damage production. Charged particle irradiation is also briefly illustrated. After discussion of the primary interaction of projectiles (neutrons, charged particles in general, and protons in particular) with target atoms/nuclei, we describe the interaction of a recoil atom with other target atoms resulting in the slowing down of the projectile, displacement damage, impurity atom production due to nuclear reactions, and the creation of atomic displacement cascades. Then the further evolution of defect structure is discussed. The next section, devoted to subcascade formation, is divided into two parts. The first experimental evidence of subcascade formation under neutron and charged particle irradiation is presented. Then the models of subcascade formation are described. Finally we review the models for the calculation of displacement damage and show how these models can be applied to displacement damage calculation under neutron irradiation with a demonstration of a real application of the methods discussed to several nuclear facilities. To cite this article: P. Vladimirov, S. Bouffard, C. R. Physique 9 (2008).