电子设备太阳辐射试验系统的研制

对自行研制的电子设备太阳辐射试验系统进行了介绍。设备研制中对试验系统的辐照灯阵进行了优化设计,同时根据环境试验要求,介绍了太阳辐射试验设备研制过程中所遇到的辐射光源选择及强度控制、光谱分布修正和光源启动系统等技术难点,并给出了解决途径。该试验系统研制成功,为考核装备的环境适应性和产品可靠性提供了科学的试验手段。     

Effect of modulated at different low frequencies microwave radiation on human EEG

This study is aimed to clarify whether effect of low-level microwave radiation on human brain differs at different modulation frequencies. Resting EEG recordings were done on different groups of healthy volunteers. The 450 MHz microwave radiation modulated at 40 and 70 Hz (15 subjects) and 217 and 1,000 Hz (19 subjects) frequencies was applied. The results of our previous study at 7, 14 and 21 Hz modulation were included into analysis. Ten cycles of the exposure (1 min off and 1 min on) at each fixed modulation frequencies were applied. The field power density at the scalp was always 0.16 mW/cm². Our results showed that microwave exposure increased the EEG energy at EEG frequencies lower or close to the modulation frequency. No effect was detected at EEG frequencies higher than the modulation frequency. Statistically significant changes were caused by exposure in the EEG alpha and beta frequency bands; no significant effect was detected in the theta band. Our results suggest that telecommunication devices with complex spectrum of modulation frequencies like mobile phone can affect all human EEG frequency bands.     

Electrochemical incineration of high concentration azo dye wastewater on the in situ activated platinum electrode with sustained microwave radiation

In this study, an in situ microwave activated platinum electrode was developed for the first time to completely incinerate the azo dye simulated wastewater containing methyl orange. The experiments were carried out in a circulating system under atmospheric pressure. Azo bond of methyl orange was partly broken on Pt, certain decoloration was reached, and the total organic carbon was not removed effectively without microwave activation. However, methyl orange was mineralized completely and efficiently on the in situ microwave activated Pt. 2,5-Dinitrophenol, p-nitrophenol, hydroquinone, benzoquinone, maleic and oxalic acids are the main intermediates during degradation of methyl orange. Aromatic products are the main substances leading to the poisoning of Pt and decrease of electrochemical oxidation efficiency, so methyl orange removal can not be carried out thoroughly. However, the intermediates were broke down quickly with in situ microwave activation promoting the mineralization of methyl orange on Pt.     

Predicting the effects of ionising radiation on ecosystems by a generic model based on the Lotka–Volterra equations

The present work describes a model for predicting the population dynamics of the main components (resources and consumers) of terrestrial ecosystems exposed to ionising radiation. The ecosystem is modelled by the Lotka–Volterra equations with consumer competition. Linear dose–response relationships without threshold are assumed to relate the values of the model parameters to the dose rates. The model accounts for the migration of consumers from areas characterised by different levels of radionuclide contamination. The criteria to select the model parameter values are motivated by accounting for the results of the empirical studies of past decades. Examples of predictions for long-term chronic exposure are reported and discussed.     

Long-term investigation of anthropogenic and naturally occurring radionuclides at reference sites in western Sweden

In case of an accidental release of radioactive substances into the environment, it is important to quickly and reliably estimate the radiation dose received by people in the affected area, and to determine the extent of the contamination. Measurements of the extent of the release and the subsequent contamination can be facilitated if there are predetermined reference sampling sites with known background radiation and inventory of radionuclides. Since 1996, 34 reference sites for soil sampling, field gamma, and intensimeter measurements have been established in western Sweden. Time series data for dose rates and radioisotope inventory have been collected at these sites, allowing for the investigation of changes in these parameters over time. The mass activity densities for the uranium and thorium series elements varied approximately between 10 and 50 Bq/kg and between 10 and 40 Bq/kg, respectively. The mass activity density of ⁴⁰K was approximately in the range 300–800 Bq/kg. The radiation exposure due to ¹³⁷Cs was rather small in this area. The dose rates calculated from in situ measurement data showed that the contribution to the total dose rate was almost entirely due to naturally occurring radionuclides. The measured dose rate was about twice as high as the calculated rate, even after subtracting the contribution from cosmic radiation. This may be explained by the fact that intensimeters generally are calibrated to measure the quantity ambient dose equivalent, which should not underestimate the effective dose.     

近50年来云贵高原太阳辐射变化特征及影响

到达地面的太阳辐射变化会对气候和生态环境产生较大影响。用云贵高原1961～2009年日射站辐射和气象观测资料,对多年来到达地面太阳总辐的年和季节变化趋势,及辐射变化对气候要素的影响进行了分析。结果表明：1961~1988年,总辐射呈明显下降趋势,之后发生逆转,1988~1994年总辐射呈显著上升趋势,1994年后其变化趋于缓和。总体呈现变暗－变亮－变缓的趋势。各季节总辐射变化的趋势为,秋季变化趋势极显著,春季变化的趋势显著,夏季变化的趋势较显著,冬季变化不明显。高原日照时数变化趋势与总辐射经历的变暗－变亮－变缓在时间上基本一致。总辐射变化对该地区的最高气温影响显著,但对蒸发量的影响不太明显。影响年辐射变化的各因子中,云量是影响高原总辐射变化的主要因素,相对湿度和能见度则影响较小     

几种涂层氙弧灯光老化试验加速性研究

太阳辐射是引起有机材料老化的最主要原因,实验室氙弧灯光老化试验具有较高的加速性。本文通过对有机涂层在广州试验站自然暴露试验结果以及实验室氙弧灯光老化试验结果进行对比研究,得到3种常用有机防护涂层的加速倍数,对于1#、2#样品的加速倍数为9,3#样品的加速倍数为6。     

低温结晶净化柠檬酸盐解吸贫液中硫酸根

在柠檬酸盐吸收—解吸脱硫技术中,完成循环吸收过程的吸收液由于烟气杂质催化和高温解吸变成了含低二氧化硫浓度、中高硫酸根浓度、多种有机酸共存的柠檬酸盐解吸贫液,造成吸收效率下降、SO2平衡容量严重降低,必须进行溶液净化,特别是净化硫酸根。针对这一问题,实验室采用低温结晶法净化柠檬酸盐脱硫解吸贫液模拟液,通过对溶液中硫酸根浓度分析,研究了不同反应时间、温度、初始硫酸根浓度、柠檬酸根总浓度和溶液p H对硫酸根去除效率的影响。结果表明,硫酸根去除率与冷冻温度和溶液p H有关。在柠檬酸根总浓度1.5 mol/L,初始硫酸根浓度40 g/L,冷冻温度3℃,p H 4.5的条件下,可将硫酸根净化至16.9 g/L。     

Mycobiota and mycotoxins in bee pollen collected from different areas of Slovakia

Contamination by microscopic fungi and mycotoxins in different bee pollen samples, which were stored under three different ways of storing as freezing, drying and UV radiation, was investigated. During spring 2009, 45 samples of bee-collected pollen were gathered from beekeepers who placed their bee colonies on monocultures of sunflower, rape and poppy fields within their flying distance. Bee pollen was collected from bees’ legs by special devices placed at the entrance to hives. Samples were examined for the concentration and identification of microscopic fungi able to grow on Malt and Czapek-Dox agar and mycotoxins content [deoxynivalenol (DON), T-2 toxin (T-2), zearalenone (ZON) and total aflatoxins (AFL), fumonisins (FUM), ochratoxins (OTA)] by direct competitive enzyme-linked immunosorbent assays (ELISA). The total number of microscopic fungi in this study ranged from 2.98 ± 0.02 in frozen sunflower bee pollen to 4.06 ± 0.10 log cfu.g^?1 in sunflower bee pollen after UV radiation. In this study, 449 isolates belonging to 21 fungal species representing 9 genera were found in 45 samples of bee pollen. The total isolates were detected in frozen poppy pollen 29, rape pollen 40, sunflower pollen 80, in dried poppy pollen 12, rape pollen 36, sunflower 78, in poppy pollen after UV radiation treatment 54, rape 59 and sunflower 58. The most frequent isolates of microscopic fungi found in bee pollen samples of all prevalent species were Mucor mucedo (49 isolates), Alternaria alternata (40 isolates), Mucor hiemalis (40 isolates), Aspergillus fumigatus (33 isolates) and Cladosporium cladosporioides (31 isolates). The most frequently found isolates were detected in sunflower bee pollen frozen (80 isolates) and the lowest number of isolates was observed in poppy bee pollen dried (12 isolates). The most prevalent mycotoxin of poppy bee pollen was ZON (361.55 ± 0.26 μg.kg^?1), in rape bee pollen T-2 toxin (265.40 ± 0.18 μg.kg^?1) and in sunflower bee pollen T-2 toxin (364.72 ± 0.13 μg.kg^?1) in all cases in frozen samples.