洞庭平原褐家鼠种群动态和繁殖特性

褐家鼠是洞庭平原稻作区的主要害鼠之一，在房舍区数量动态复杂，季节消长基本上属春冬双峰型，在农田区数量季节消长为夏秋双峰型。褐家鼠总雌性比为５２．０％，全年繁殖．３～１０月为繁殖盛期，盛期平均怀孕率为３４．９１±８．６９％，平均胎仔数为８．２±ｌ．０，４、７、９月出现怀孕高峰，１１月至翌年２月为繁殖低潮期。褐家鼠在洞庭平原７０年代数量较低，８０年代初暴发成灾，８０年代后期数量有逐步下降趋势。针对种群特征，提出了控制褐家鼠种群数量的对策。     

环境试样中痕量砷的形态分析研究

提出了湖水和土壤中痕量砷的形态分类方案,研究备形态的分离与测定.水样以0.45μm膜过滤分离出悬浮态的砷,用活性炭分离砷的胶态与游离态;土壤样品依次用水、稀盐酸提取.0.45μm膜过滤,得到水溶态、酸溶态和残余态,前两者用活性炭方法分离胶态与游离态;以巯基棉纤维分离,二巯基丙醇衍生气相色谱法测定各形态的砷的总量及胶态与游离态中砷的价态、无机态和有机态,从而建立湖水和土壤中痕量砷的形态分析方法.     

Studies on Classification of Recreational Fishery Resources and Evaluation on its Development

Recreational fishery is the combination of traditional fishery and modern leisure activities. Development of recreational fishery resources must be based on related resources, but the present research on recreational fishery is mainly confined to the development of leisure projects, the definition of connotation and scope of recreational fishery resources is rather vague, and there is no precise classification and evaluation system. According to the resources attributes, resources functions, and tourism resources classification, investigation and evaluation standard, recreational fishery resources include a number of different types. Expert Scoring Method and Analytic Hierarchy Process can be used to determine the evaluation factors of recreational fishery resources and their weights, and then make comprehensive evaluation on recreational fishery resources of different regions and types, so as to improve the scientific nature of recreational fishery development.     

湘潭某新建小学安全现状及管理措施研究

为减少湘潭某新建小学校园安全事件的发生,本文采用安全检查表对该校进行安全隐患排查,通过排查发现该校存在一定的安全隐患问题,主要集中在“物的不安全状态”和“不良环境”2个方面,针对隐患依据4M理论从“人—机—环—管”4个方面提出合理可行的安全管理措施及隐患消除方法。经分析,该校校园环境中存在的安全隐患可通过采取科学有效的方法进行治理。希望本研究可以为小学校园安全管理提供一定的思路。     

某型导弹尾翼弹簧贮存寿命评估

应力松弛是弹簧的主要失效形式之一,温度对其影响明显。利用温度加速试验方法,对某尾翼弹簧的贮存寿命进行了研究。设计并制造了弹簧的应力松弛试验装置,利用该装置对弹簧设计了4个试验温度点,并以弹簧应力损失率下降10%为失效指标,根据阿伦尼乌斯方程对弹簧进行了贮存寿命预测,评估了该弹簧在室温条件下的贮存寿命。     

Chemical constituents of one endophytic fungus isolated from Cordyceps sinensis北大核心CSCD

The study focused on the analysis of the chemical constituents of ethyl acetate extracts of Penicillium herquei, an endophyte of Cordyceps sinensis. The compounds were isolated and purified by chromatographic procedures and identified on the basis of spectral methods. Eleven compounds were identified: 2′,4′-dihydroxy-3′,5′-dimethylacetophenone (1), vanillin (2), 3-oxo-α-ionone (3), 3,3,5-trimethyl-4-(3-oxo-1-butenyl)cyclohexan-1-one (4), p-hydroxybenzaldehyde (5), p-hydroxyacetophenone (6), methyl p-hydroxyphenylacetate (7), cyclo-(Pro-Ile) (8), cyclo-(Pro-Val) (9), 4-methoxyphenylacetic acid (10), and cyclo-(4-methyl-Pro-Val) (11). Benzaldehydes, ionones, and cyclodipeptides are the major metabolites of the P. herquei from C. sinensis. © 2018 Science Press. All rights reserved.     

MicroRNAs and their role in environmental chemical carcinogenesis

Environmental Geochemistry and Health - MicroRNAs (miRNAs) are a class of small, noncoding RNA species that play crucial roles across many biological processes and in the pathogenesis of major...     

Enhancing short-term ethanol-type fermentation of waste activated sludge by adding saccharomycetes and the implications for bioenergy and resource recovery

Ethanol-type sludge fermentation has recently attracted much attention because it can enhance direct interspecies electron transfer and thus improve the anaerobic digestion of waste activated sludge(WAS). In this paper, the enhancement of short-term ethanol-type fermentation of WAS via adding Saccharomyces was investigated. The experimental results show that the maximum ethanol production of 1030.8 ± 20.6 mg/L was achieved, with the optimum fermentation conditions of a p H of 5.1, temperature of...     

特种方舱铁路运输异常调车纵向冲击试验研究

目的 针对特种方舱铁路运输,明确异常调车纵向冲击试验方法,并掌握异常纵向冲击安全性边界.方法 首先开展"一车冲一车"、"一车冲三车"铁路冲击对比试验,获得2种工况下的冲击特性数据.然后,基于冲击试验获得的缓冲器性能,建立特种方舱铁路运输调车作业动力学模型,研究冲击模式下不同冲击速度的纵向冲击特性.结果 试验工况1(冲击...