我国辐射化学的发展

简要地从聚合物的辐射化学、生物相关材料的辐射效应、辐射加工技术、辐射剂量检测、以及辐射在环境保护中的应用等方面综述了我国在辐射化学领域的一些重要进展。     

Radiation Chemistry and Radiation Technology at the Boundary of the Centuries: The Current Status and Prospects for Development

A brief review of the current status of radiation chemistry and radiation technology is presented. Particular attention is focused on the results of studies performed in the last five to six years of the 20th century. Data on the most important branches and the most considerable advances in modern radiation chemistry are given. Recent achievements in radiation technology are summarized. A forecast of the development of radiation chemistry and radiation technology technology for the next few decades is made.     

Coherent polarization radiation from crystals irradiated with relativistic charged particles

When polarization radiation (polarization bremsstrahlung) occurs in a crystal, the radiation becomes coherent in X-ray wavelengths. This radiation, called coherent polarization radiation (CPR) in this paper, is considered as a possible compact X-ray source because CPR is intense, monochromatic, tunable, small background, and easy to extract. We present a simple theory of CPR with emphasis on its relation to Cherenkov radiation and transition radiation. Various properties of CPR are also discussed.     

Water‐Filtered Infrared Radiation Decreases the Generation of Photodermatoses Dependent on Ultraviolet and Visible Radiation

The potential role of infrared radiation in photodermatoses has received very little attention, even though the main sources of radiation used for photobiological studies (UVA, UVB and visible light) include infrared radiation. The objective of the work was to assess whether infrared radiation is involved in the development of skin lesions in patients with different types of photodermatoses. Twenty patients with different photodermatoses were exposed to UVA, UVB and visible radiation using a high‐pressure mercury UVA lamp, a fluorescent broadband UVB lamp, a tungsten bulb and a slide projector for visible radiation. Part of the radiation emitted by these lamps was water‐filtered to block infrared radiation above 1300 nm. All 20 patients developed lesions when exposed to different light sources used for phototest. When exposed to same sources without infrared radiation, 17 patients (85%) did not develop any lesions and the other three (15%) developed less severe lesions than in the area exposed to unfiltered light. Our results show that infrared radiation was necessary for the development of skin lesions in 85% of the patients with photodermatoses in our study. We believe that infrared radiation studies should be included in standard photobiology protocols.     

Radiation doses at high altitudes and during space flights

There are three main sources of radiation exposure during space flights and at high altitudes—galactic cosmic radiation, solar cosmic radiation and radiation of the earth's radiation belt. Their basic characteristics are presented in the first part of this paper.Man's exposure during space flights is discussed in the second part of the paper. Particular attention is devoted to the quantitative and qualitative characteristics of the radiation exposure on near-earth orbits: both theoretical estimation as well as experimental data are presented. Some remarks on radiation protection rules on-board space vehicles are also given.The problems connected with the radiation protection of air crew and passengers of subsonic and supersonic air transport are discussed in the last part of the paper. General characteristics of on-board radiation fields and their variations with flight altitude, geomagnetic parameters of a flight and the solar activity are presented, both based on theoretical estimates and experimental studies. The questions concerning air crew and passenger radiation protection arising after the publication of ICRP 60 recommendation are also discussed. Activities of different institutions relevant to the topic are mentioned; strategies to manage and check this type of radiation exposure are presented and discussed. Examples of results based on the author's personal experience are given, analyzed and discussed.     

低剂量CT扫描技术在肋骨骨折检查中的研究进展

X线自发现以来,在医学领域运用越来越广泛.但是,医疗用X射线是人类最大的人为辐射来源,并认为辐射是造成癌症等疾病发生的重要危险因素.目前,CT扫描对肋骨骨折的诊断已被认为是最佳检查技术,但人体所受辐射剂量会明显增大.通过降低管电流、管电压、增大螺距,以及根据体重指数或噪声水平设定、采用迭代重建技术等多种方法降低CT扫描...     

Comparison of degradation effects induced by gamma radiation and electron beam radiation in two cable jacketing materials

The radiation degradation behavior of commercial low density polyethylene (LDPE) and ethylene–vinylacetate (EVA) cable materials has been investigated. The changes of mechanical properties, thermooxidative stability and density exhibit different radiation stability towards ⁶⁰Co-gamma radiation and 160 keV electron beam radiation. This difference reflects much higher penetration of the gamma radiation through the polymeric material as a function of sample thickness. These results are discussed with respect to the role of beta radiation during design basis events in a nuclear power plants. In case when total accidental design basis event (DBE) dose (involving about 80% soft beta radiation) is simulated by ⁶⁰Co-gamma radiation the conservatism is reached.     

UV-induced changes in pigment content and light penetration in the fruticose lichen Cladonia arbuscula ssp. mitis

The response of the lichen, Cladonia arbuscula (Wallr.) Flot. ssp. mitis (Sandst.) Ruoss to enhanced UV-B (280-315 nm) radiation was investigated with respect to: (a) changes in phenolic content; (b) differential pigment accumulation under visible and UV radiation with increasing distance from thallus apices; and (c) the internal distribution of UV-B radiation within the thallus measured with quartz optical fibres. In a short-term experiment, lichens were exposed for 7 days in a growth chamber to visible light with or without additional UV-B radiation. For a longer term experiment, lichens were grown outdoors under both natural UV radiation, and supplemental UV-A (315-400 nm)+UV-B provided by lamps. Controls were placed under filters that removed the radiation below 290 nm from the natural sunlight. The concentration of total phenolic compounds was measured spectrophotometrically at the termination of the experiments, in different parts of the lichen podetia. UV-exposed lichens showed increased accumulation of phenolics compared to those not grown under UV. At the termination of the long-term experiment, fibre optic measurements of the penetration of radiation into lichen thallus reflected the influence of growth under UV radiation, whereby UV was more strongly attenuated as compared to that in lichens not exposed to enhanced levels of UV-B radiation. Results indicated that in Cladonia, UV-B radiation induces the accumulation of phenolic compounds that may have a protective role. In addition, the morphological distribution of phenolic compounds was different under visible and supplemental UV-B radiation. Internal radiation measurements served to visualise the attenuation of radiation with thallus depth for different wavelengths in the UV-B waveband.     

MUTATION AND SISTER CHROMATID EXCHANGE INDUCTION IN CHINESE HAMSTER OVARY (CHO) CELLS BY PULSED EXCIMER LASER RADIATION AT 93 nm AND 308 nm AND CONTINUOUS UV RADIATION AT 254 nm

We compared mutagenesis and sister chromatid exchange (SCE) induction by 193 nm and 308 nm pulsed excimer laser radiation with 254 nm low intensity continuous wave UV light in Chinese hamster ovary (CHO) cells in culture. The 254 nm radiation was most mutagenic of the radiations, in accordance with expectation, and also was most effective in increasing the level of SCEs. The 193 nm radiation was mutagenic at the ouabain resistance locus, but not at the HGPRT locus. However, 193 nm radiation was also strongly cytotoxic at energies producing measurable mutations. This radiation also caused a dose-related increase in SCEs. Pulsed excimer radiation at 308 nm was mutagenic at both loci, and also increased the incidence of SCEs. Comparison of the ratio of mutants/surviving cells at the D37 after radiation showed similar values for 254 nm and 308 nm at the HGPRT locus, but at the ouabain resistance locus, the ratio for the 308 nm radiation was about 5 times that for 254 nm radiation. These results indicate that some risk for mutagenesis may accompany the use of excimer radiation in the UVA region in therapeutic applications.     

The Effects of Ambient Solar UV Radiation on Alkaloid Production by Erythroxylum novogranatense var. novogranatense†

Truxillines are alkaloids produced by Erythroxylum species and are thought to be derived from the UV‐driven dimerization of cinnamoylcocaines. This study was conducted to determine the effects of ambient UV radiation on the production of truxillines in Erythroxylum novogranatense var. novogranatense. Field plants were grown under shelters covered with plastic filters that were transparent to UV radiation, filtered UV‐B, or both filtered UV‐B and UV‐A radiation. The treatments had no significant effect on plant biomass or specific leaf weight. Absorption values in the UV‐C and UV‐A region of acidified‐methanol leaf extracts were higher for plants exposed to UV radiation compared to the no UV radiation treatment. There was a trend in decreasing levels of trans‐cinnamoylcocaine and a statistically significant decrease in levels of cis‐cinnamoylcocaine in the leaves of plants exposed to UV radiation compared to the no UV radiation treatment. Truxilline levels increased in leaves from plants exposed to UV radiation compared to the no UV radiation treatment. Most significantly, the ratio of truxillines to total cinnamoylcocaines in the leaves was affected by UV, increasing with increased UV exposure. The results support the hypothesis that UV radiation is involved in the formation of truxillines from cinnamoylcocaines.     

溶液中纳米SnO2颗粒的瑞利和超瑞利散色

Rayleigh and Hyper-Rayleigh scatterings (HRS) from the nano-particle SnO2 were measured. It is found that as the concentration of the colloidal SnO2 or radiation power increases, the first- and second-order polarizabilities decrease. The radiation power dependencies of the first- and second-order polarizabilities show two domains: in high radiation power domain, the first- and second-order polarizabilities are approximately constant, in low radiation power domain, the first- and second-order polarizabilities increase sharply and become sensitive to the radiation power. The behavior of the concentration dependencies of the first- and second-order polarizabilities of colloidal SnO2 particles is similar to that of the radiation power dependence. A detailed mechanism explaining these phenomena has been discussed.     

Studies of radiosterilization and radiation effect on disposable medical products and their packing materials

This report describes the studies of radiation effects in the physical and chemical properties of various disposable medical products, such as catguts, syringes and theirpacking materials; toxic tests on them; sufficient radiation conditions and radiation doses. These studies could provide the basis for production of medical products and quality assurance of radiation sterilization.     

微波技术应用于钼铁中钼含量的测定

将微波辐射作为一种加热方法应用于钼铁中钼含量的测定.将钼铁试样经处理转化为8-羟基喹啉钼[MoO2(C9H6NO)2]沉淀后,以不同的微波功率和照射时间对沉淀物进行干燥试验,确定出了最佳微波功率为680 W,最佳照射时间为12 min.结果表明,利用微波照射替代电烘箱加热,可使沉淀物的干燥时间由12 h缩短为12 min.     

聚硅氧烷辐射效应研究进展

综述了聚硅氧烷在不同类型辐射下的辐射效应及其各种影响因素,并展望了提高聚硅氧烷耐辐射性能的途径。     

Measurement of solar ultraviolet radiation at a temperate and a tropical site using polysulphone film

Measurements of solar ultraviolet radiation (<320 nm) have been made with polysulphone film at a temperate and a tropical site and compared mean monthly values of the fraction of ultraviolet in solar radiation are calculated which allow an estimate of ultraviolet dose to be made from a knowledge of total solar radiation.While the data demonstrate the marked effect of sun elevation on the ultraviolet fraction of solar radiation they also indicate the effect of seasonal variation in the thickness of the ozone layer above the temperate site.It is also shown that whereas sunlight makes by far the major contribution to total solar radiation, skylight is of prime importance as regards ultraviolet radiation.     

Die sekundäranregung bei der Röntgenfluoreszenzanalyse ebener dünner schichten

The characteristic radiation of thin element films is in certain cases excited by the characteristic radiation of the substrate material, or, on the contrary, the thin film radiation is able to excite the substrate radiation. Based on theoretical considerations a calculation of this effect is given.

For thin film radiation the amount reaches up to 25 per cent of the total intensity and for substrate radiation at maximum 5 per cent.

Thin alloy films show a secondary excitation as well as bulk materials, but the influence is comparably smaller. At film thicknesses of approximately 1000 Å maximum values of 2 per cent of the total intensity have been calculated.     

Rayleigh and Hyper-Rayleigh Scatterings from the Nanometer SnO_2 Particle in Solution

Nano-materials have been extensively studied in the past[1]. The quantum effect makes the properties of nano-materials dif- ferent from that of bulk materials. A few of publications regard- ing the catalysis, electronic structure, and optics of the nanome…     

聚乙烯醇的强化辐射交联

通常γ-辐照裂解的聚乙烯醇(PVA)在N·N’-甲基丙烯酰胺(BAM)存在下可以辐射交联。BAM/PVA体系的辐射效应可大致依辐照剂量的增加划分为三个阶段:强化辐射交联为主区,强化辐射交联与辐射裂解相抵区和辐射裂解优势区。强化辐射交联区的溶胶分数S与辐照剂量D的关系可表示为: S=(1 (1/(1-K))D_g~(2=K))-(D_g/(1-K))D~(1-K) =A-BR~(1-K)式中,D_g为凝胶化剂量;K是与BAM含量相关的常数。     

125I内照射的小鼠血清中5种微量元素水平变化

对小鼠灌喂含125I放射性物质,建立放射性内照射模型,应用原子吸收光谱法测定了低、中、高辐射源剂量组及对照组小鼠血清中Zn、Cu、Fe、Mg、Mn的含量.结果表明,采用辐射源灌喂的小鼠血清中5种微量元素含量均低于没有灌喂辐射源的对照组,5种微量元素的含量随着辐射剂量的增加而降低.结果提示,通过科学膳食补充人体必需微量元素,对于积极防御辐射对机体健康产生的危害极为重要.     

Provisional regulation of metrological supervision and management for radiation processing in China

In order to implement the “Law of metrology of the People's Republic of China” for guaranteeing the product quality of radiation processing, safeguarding State's interest and people's health, promoting the progress of radiation processing techniques, SBTS and SCST have jointly issued “the Provisional Regulation of Metrological Supervision and Management for Radiation Processing”, according to present situation of ionizing radiation measurement in radiation precessing plants. This is an administrative rule, which provides the regulation of radiation measurement licence for radiation precessing plants. SBTS has decided to establish the State Office of Technical Examination for Measurement Licence of Radiation Processing, which is attached to the National Institute of Metrology (NIM). Its main tasks include establishment of examination plans for radiation processing licence, organization of technical examination and other works related to the measurement regulation and performance of measurement supervision and regulation inradiation processing fields.