六氟苯(C_6F_6)体系中氧对正子素(Ps)寿命的影响

本工作研究了溶解在六氟苯(C_6F_6)中的氧对正子素(Ps)寿命的影响。分别得到了在C_6F_6中三重态正电子素(O-Ps)的原始摘除寿命τ_3~0=4.15 ns;氧猝灭O-Ps的速率常数k_(O_2)=1.8×10~(10)(1mol~(-1)s~(-1));三重态激发分子~3(C_6F_6)猝灭O-Ps的速率常数k~3(C_6F_6)=1.7×10~(10)(1mol~(-1)s~(-1)),以及六氟苯体系中三重态激发分子~3(C_6F_6)猝灭O-Ps的贡献。结果表明:~3(C_6F_6)对O-Ps寿命的影响并不很大。     

放射性同位素X荧光测井技术的研究

对放射性同位素源Ｘ荧光测井技术的井液效应，井壁不平度效应和基体效应分别提出了实用的校正技术。野外锶矿Ｘ荧光测井试验表明：Ｘ荧光测井确定的锶矿层厚度和平均品位与传统的岩芯化学分析结果相比较，其相对误差〈１０％，符合锶矿储量计算要求；Ｘ荧光测井可在井场实时提供测井结果，而耗时却短得多。     

聚氧化乙烯水凝胶膜的辐射接技研究(英)

为了得到一种理想的水凝胶伤口敷料,研究了应用电子束辐射接枝了不同比例聚乙烯醇（PVA）的聚氧化乙烯（PEO）水凝胶膜的制备和该膜的理化特性。实验结果显示,PEO接枝水凝胶膜的凝胶分数主要依赖于辐射剂量和聚合物浓度。而其溶胀度与辐射剂量聚合物的浓度;混合比例和分子量密切相关。该膜的抗张强度和断裂伸长率则明显地依赖于辐射剂量和聚合物的混合比例。实验发现,比例为7：3的20wt％PEOE-30接枝水凝胶膜与其它PEO接枝水凝胶膜和单纯PEOE-30水凝胶膜相比具有较好的理化特性,例如韧性,较少气泡,适度的凝胶分数,溶胀度和断裂伸长率,尤其它的较高的抗张强度。实验结果表明,PVA在辐射接枝后能够通过降低PEO水凝胶膜的溶胀度而改善PEO水凝胶膜的机械强度。     

对公众慢性照射防护的一些讨论

本文介绍了近年来国际放射防护委员会（ＩＣＲＰ）、国际原子能机构（ＩＡＥＡ）以及一些学者对公众慢性照射防护问题的一些讨论,涉及定义与范围、相关量、ＩＣＲＰ防护体系的应用以及实用指南等。它可以作为制订我国《电离辐射防护和辐射源安全的基本安全标准》的借鉴。     

ICRP1990年建议书关于辐射危险评估的新进展

本文介绍了ICRP1990年建议书附件C的主要内容,着重阐述危险的概念,描述辐射照射引起的各种潜在危险的量,一次和长期照射条件下不同年龄时危险的增量及文中用多属性方法来选择工作人员或公众个体的剂量限值。     

Etude des divers types de transformations structurales caracterisant l'alliage Zr-Nb a 17% poids de niobium

This study was carried out mainly by quenching followed by isothermal annealing or continuous heating. X-ray diffraction, micrography, microhardness and dilatometry during quench were employed. By stepped quenching, it was found that the high-temperature β phase decomposes in different ways —either partial decomposition into _Zr, leading finally to the (_Zr+β_Nb) mixture indicated by the phase-diagram, or a diffusion-transformation into ω', or else a diffusionless transformation into ω. A fast quench breaks down the phase into a complex (β + ω + β″) structure. During isothermal anneals the β″ phase was found to vanish, while either ω' or _Zr was formed according to temperature; meanwhile residual β became enriched in niobium. During continuous heating at rates less than 150°/h, the quench-product, ω, reverts to β; then, above 600°C, is transiently deposited but disappears again above 700°C to yield the equilibrium high-temperature phase, β containing 17 wt % niobium.     

Phosphate-hydroxyquinoline method for separation and volumetric determination of zirconium

The proposed method consists of a combination of the well-known phosphate method for separation of zirconium, and determination of zirconium as the hydroxyquinolate. The separation of zirconium hydroxyquinolate from an oxalate medium after solution of the phosphate preccipitate in oxalic acid has been used for the first time. The conditions of separation of zirconium from titanium and thorium in the phosphate precipitation, and from niobium and tantalum in precipitation of the hydroxyquinolate, have been studied. By this method it is possible to separate zirconium in practice from all accompanying elements (except hafnium), and to determine small amounts of zirconium (2–5 mg) by a volumetric method to an accuracy of ± 2–4%.     

Fission gas induced swelling in uranium at high temperatures and pressures

The effect of externally applied hydrostatic pressures from 0–1000 bar at 900 °C on the fission gas induced swelling in uranium has been studied. The swelling is a sensitive function of pressures below 110 bar and relatively insensitive to pressures above 110 bar. Metallography of the samples show that the average diameter of the bubbles is reduced from 3300 to 1800 Å and the total number increased from 0.9 to 4.2 × 10¹²/cm³ as the annealing pressure is increased from 0–110 bar respectively. Further increases in pressure from 110–1000 bar have little effect on the average bubble size and density. The mechanism of pressure reduced swelling is discussed in terms of the equilibrium number of vacancies that can be associated with fission gas atoms under stress. It is also shown, both experimentally and theoretically, that there is a loss of surface area when bubbles coalesce under pressure.     

7005铝合金的均匀化工艺研究

采用DSC分析、光学显微镜(OM)、扫描电镜(SEM)及力学性能测试等技术研究7005铝合金铸态和均匀化态的显微组织与性能,确定了实验合金一级均匀化及二级均匀化工艺。结果表明：实验合金经450℃,12h一级均匀化效果较佳,但合金中的残留共晶仍然较多;其二级均匀化工艺为随炉升温到450℃保温12h,再随炉升温到485℃保温4h,实验合金经二级均匀化处理后,残留共晶的数量显著减少,成分均匀,综合性能优越。实验结果表明,7005铝合金适宜的均匀化处理工艺为450℃/12h 485℃/4h。     

适用于粗颗粒矿物浮选的颗粒悬浮特性的研究

在实验室条件下通过测定新型叶轮定子系统在不同转速条件下浮选槽内的颗粒悬浮参数,确定适用于粗颗粒矿物选别的完全离底悬浮临界转速,同时对新型叶轮定子系统和普通KYF叶轮定子系统在浮选槽内的矿物颗粒悬浮参数进行对比,分析得出新型叶轮定子系统上下两个循环通道的分界面到槽底的距离比普通KYF叶轮大,可以有效提高粗重颗粒的离底悬浮高度,在避免粗颗粒矿物快速沉降的同时可以提高其回收效果。