四川燃煤电厂对周围土壤的辐射影响

燃煤电厂对环境与人群所产生的辐射影响早已引起了国内外学者的关注。本文通过对四川省境内重庆、河门口、江油等燃煤电厂烟尘中天然放射性水平的分析，估算出由烟尘沉降所造成周围土壤中天然放射性本底的年增加量不到０．１％，这说明由烟尘沉降每年对土壤所产生的辐射影响是较小的；然而由于沉降的放射性在相当长的时期内存在于土壤的表层，因此随电厂运转时间的增加，其所产生的辐射影响就必须引起重视了；本文通过对电厂周围表层与深层土中天然放射性水平的比较与分析说明，燃煤电厂的长期运转有可能使周围表层土壤中天然放射性本底增加。     

非热强介质等离子体反应器用于臭味气体的分解

对非热强介质等离子体反应器用于臭味气体———氨、硫化氢、甲基硫醇的分解进行了试验研究。研究了施加电压、停留时间、初始浓度对臭味气体分解率的影响 ,并对氨的分解产物进行了初步分析。结果表明 ,在这 3种气体的初始体积分数分别为 2 5× 10 -6和 5 0× 10 -6的条件下 ,当施加电压为 16kV、停留时间为 0 .2 3s时 ,氨的分解率达到 97%以上 ;当停留时间为0 .2 3s时 ,硫化氢和甲基硫醇分别在 10kV和 8kV时达到 10 0 %的分解。     

基于传热分析的林火蔓延特性研究

计算了水平流动的热烟气与大乔木、小乔木、灌木主干及大乔木树叶间的强制对流传热；垂直上升流动的热烟气与各类林木的纵向自然对流、纵向强制对流传热；以及烟气对各类林木的辐射传热。分别比较了它们的热流密度和总换热量。讨论了烟气流速、温度、林木尺寸等因素对换热的影响。在此基础上，对不同林木的火险特性进行了预测。     

红外探测巷道围岩地质构造的理论与应用

利用红外技术探测地质构造是预防巷道作业重大安全事故的有效途径。笔者根据红外辐射原理 ,分析了地质构造引起的岩石密度变化和巷道围岩辐射功率之间的相关性 ,提出了红外探测巷道地质构造的理论、方法及适用条件。应用结果表明 :红外探测技术不仅可简便、直观地分析和预测采掘巷道围岩地质的变化趋势 ,而且可用于巷道围岩瓦斯涌出异常地段的原因探测 ,指导安全防范措施的有效实施     

居室放射性

本文介绍了放射性的来源,讨论了室内γ射线和氡及其子体,计算了相关的年剂量当量     

浅谈超低频电磁波异常与相关地震

介绍了锦州东港电力有限公司地震台多年来应用超低频电磁信息探索地震前兆所总结出的异常形态分别与远震、近震、地方震的对应实例,揭示了ＵＬＦ电磁波异常与将要发生地震映震的一些初步规律,说明了电磁波是地震短临预报的好方法。     

Short-term wind speed forecasting based on random forest model combining ensemble empirical mode decomposition and improved harmony search algorithm

ABSTRACT

Wind speed forecasting plays an important role in power grid dispatching management. This article proposes a short-term wind speed forecasting method based on random forest model combining ensemble empirical modal decomposition and improved harmony search algorithm. First, the initial wind speed data set is decomposed into several ensemble empirical mode functions by EEMD, then feature extraction of each sub-modal IMF is performed using fast Fourier transform to solve the cycle of each sub-modal IMF. Next, combining the high-performance parameter optimization ability of the improved harmony search algorithm, two optimal parameters of random forest model, number of decision trees, and number of split features are determined. Finally, the random forest model is used to forecast the processing results of each submodal IMF. The proposed model is applied to the simulation analysis of historical wind data of Chaoyang District, Liaoning Province from April 27, 2015 to May 22, 2015. To illustrate the suitability and superiority of the EEMD-RF-IHS model, three types of models are used for comparison: single models including ANN, SVM, RF; EMD combination models including EMD-ANN, EMD-SVM, EMD-RF; EEMD combination models including EEMD-ANN, EEMD-SVM, EEMD-RF. The analysis results of evaluation indicators show that the proposed model can effectively forecast short-term wind data with high stability and precision, providing a reference for forecasting application in other industry fields.     

Catalytic decomposition of hydrocarbon into hydrogen and carbon in a spouted-bed reactor as the second-stage reactor of a plastic recycling process

A two-stage process for the chemical recycling of plastics is proposed. In this process, which consists of two reactors, plastics are converted into hydrogen and carbon. In the first reactor, plastic chips are thermally decomposed into hydrocarbons. In the second reactor, the hydrocarbons formed in the first reactor are catalytically decomposed into carbon and hydrogen. In this study, in order to obtain basic data for the second reactor, propene was catalytically decomposed in a laboratory-scale spouted-bed reactor (600mm high, 21.6mm internal diameter, made of SUS304). The effect of the type of spouting medium used on the decomposition behavior of propene was investigated using four types of spouting medium (nickel-plated -alumina, palladium-plated -alumina, nickel-impregnated -alumina, and -alumina). The nickel-impregnated -alumina gave the best propene conversion and hydrogen yield.     

Preliminary indoor radon risk assessment at the Poços de Caldas Plateau,MG-Brazil

This paper aims to present an assessment of the environmental radiological exposure at a Brazilian area of high natural radiation and discusses the indoor radon exposure risk. A survey of inhabitant exposures arising from the inhalation of radon progeny and external gamma exposure was conducted in urban and rural areas of the Po?os de Caldas Plateau, which is recognized worldwide as a high natural radiation region. The results of this survey indicated that highest radiation exposure was restricted to the rural area of Po?os de Caldas. The radiation exposure in urban locations was quite similar to the values observed in normal background areas in some Brazilian counties. By the application of a constant relative risk model, an additional 20% in the lifetime risk of lung cancer mortality due to the exposure to radon progeny was estimated at Po?os de Caldas. It was also estimated that 16% of all lung cancer deaths at Po?os de Caldas county could be attributable to radon exposure.     

Lowest Effect Levels of Lead and Mercury on Decomposition of Mor Layer Samples in a Long-Term Experiment

Indications of possible negative effects of lead (Pb) and mercury(Hg) on microbial respiration in Southern Swedish forest humus layers led to experiments on dose-response relationships by additions of metal salts in the laboratory. Respiration rates andweight loss due to decomposition of organic material were measured. For relevance to field situations metal doses were low,the time span was long, 550 days including freeze storage, and microbial activity was kept up by plant litter additions. We looked for effects of Pb and Hg at levels moderately elevated above the Southern Swedish reference, as well as combined effectsof Pb + Hg. A reduction in respiration and decomposition of10% was found at about 225–245 g g^-1 of total Pb, i.e. ata Pb level elevated 3.5 times. Although small effects of Hg werefound even at the lowest dose level, 10% inhibition of microbialactivity appeared temporarily at about 2–3 g g^-1 of total Hg, i. e. at 6–8 times the reference level. There were nolong-term additive effects of Pb and Hg on decomposition. Type of anion had a strong influence on the test, chlorides of Pbbeing more toxic than nitrates. Long-term monitoring and maintenance of microbial activity during the experiment were prerequisites for the occurrence of effects at low metal levels.