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储藏玉米陈化机理及挥发物与品质变化的关系 总被引：7，自引：2，他引：5
为了找寻挥发性物质与玉米储藏品质指标的关系,探讨玉米品质变化机理.对重庆地区不同储藏时间的玉米,采用项空气相色谱-质谱联用法测定其挥发性物质,同时测定其生理、生化指标,研究挥发性物质的种类和含量及其与储藏时间、生理、生化指标的相关性.研究结果表明:不同储藏时间的玉米挥发性物质种类基本相同,只是在量上存在差异.随着储藏时间的延长,玉米的总挥发性物质以及单个挥发性物质含量逐渐增加.总挥发性物含量、丙酮、对环己二烯、环戊乙炔、乙酸、己醛的含量与储藏时间、生理生化指标呈较高相关性,可作为玉米储存品质变化的评判指标.储存玉米的挥发性物质主要是由脂质的氧化和水解产生的. 相似文献
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金橘皮中黄酮类物质的提取及其体外抗氧化活性研究 总被引：10，自引：1，他引：9
为了确定金橘皮中黄酮类物质的提取工艺和初步鉴定该类物质的活性,该文以黄酮得率为考察指标,比较了不同溶剂对金橘皮黄酮类物质的提取效果,并采用正交试验,研究了提取溶剂浓度、提取温度、时间和料液比对金橘皮黄酮类化合物提取的影响.同时,以粗黄酮类物质的还原能力、对超氧阴离子自由基(O2·)、羟基自由基(·OH)的清除率作为考查指标,研究了金橘皮黄酮类物质的体外抗氧化活性.确定了最佳提取工艺条件为:最佳提取溶剂为甲醇,甲醇浓度为60%,料液比为1:40,温度80℃,提取时间4 h.粗黄酮具有较强的还原能力,高于同浓度下的抗氧化剂2,6-二叔丁基对甲酚(BHT)和没食子酸丙酯(PG);对O2-、·OH均具有良好的清除作用,但对O2·的清除效果更好. 相似文献
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有机物质种类对污染土壤铜形态及活性的影响 总被引：16，自引：0，他引：16
本文试验研究了几种有机物质对冶炼厂附近污染土壤中铜形态及其活性的影响 .结果表明 ,有机物质添加后对土壤铜化学形态与活性的影响进程较为迅速 ,半个月内就有明显的表现 :不同类型有机物质都对土壤铜的化学活性有控制作用 ,但控制效果因有机物质种类而异 ,且与有机物质在土壤中腐解转化有关 . 相似文献
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生活垃圾堆肥过程中恶臭物质分析 总被引：12，自引：6，他引：6
恶臭污染已成为生活垃圾堆肥过程中的主要环境问题.以15~80 mm粒径段的生活垃圾作为研究对象,利用嗅觉测定法和GC-MS分析了不同阶段堆肥尾气的臭气浓度和恶臭化合物的种类及其排放浓度,并对不同堆肥阶段臭气浓度和恶臭物质排放浓度的相关性进行分析.结果表明,垃圾堆肥过程中共检测到50种挥发性有机物,其中含硫恶臭物质5种,烃类化合物25种,芳香烃类化合物14种,其他物质6种.通过相关性分析,发现硫化氢、甲硫醚、二硫化碳、二甲二硫、1,3二甲基苯和邻二甲苯均与臭气浓度呈极显著相关(p<0.01),结合各恶臭物质的嗅阈值,15~80 mm粒径段垃圾堆肥过程中恶臭物质优先控制的顺序为硫化氢>甲硫醚>二甲二硫>二硫化碳>1,3二甲基苯>邻二甲苯.甲硫醇的嗅阈值非常低,即使其排放浓度很低,也会带来严重的臭气污染;NH3虽然对臭气浓度的贡献相对较小,但是其排放量很大,因此也应该对这2种恶臭物质进行重点监测和控制.该研究结果为生活垃圾堆肥过程中恶臭物质的监测、制定控制策略提供参考. 相似文献
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对废弃物食物链发酵基料 蚯蚓 鳝鱼的物质流和能量流转化效率研究结果表明 ,该食物链经济产品物质、能量转化效率较低 ,生物量转化效率为 0 .9% ,N、P转化效率分别为 2 .1 %和 0 .6 % ,能量转化效率为 1 .0 % ,其经济和生态效益明显 相似文献
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转基因植物标准物质研究进展 总被引：2，自引：0，他引：2
转基因产品的安全性一直都备受关注,因此转基因产品的定性、定量检测越来越重要,而转基因标准物质的使用是转基因产品检测结果有效和可比的重要保证.本文针对国内外转基因植物标准物质的研究现状及相关技术进行综述,重点介绍了转基因植物标准物质的种类、转基因标准物质定值技术,分析了转基因标准物质研制过程中的关键点.更重要的是综述并提出了质粒DNA分子标准物质的定值模式,包括如何合理评价质粒分子可替代性问题,此外还总结了目前国外转基因标准物质的种类,目的是为我国转基因植物标准物质研制和相关研究提供有价值的参考. 相似文献
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土壤腐殖物质的形状,与土壤物理性质和物理化学性质有密切关系.已经知道,线型分子对土壤颗粒的团聚化有着特别良好的作用[1].腐殖物质是土壤中主要的有机物质. 相似文献
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不同氮磷钾配施对烤烟石油醚提取物和中性致香物质的影响 总被引：11，自引：0，他引：11
田间试验以烤烟(Nicotiana tabacum L.)品种中烟100为材料,研究了N、P、K肥配施对烤烟石油醚提取物和致香物质含量的影响.结果表明:不施肥处理烟叶石油醚提取物含量和致香物质总量及不同种类致香物质含量都较低:N、P、K任意两种肥料配施均可以不同程度提高烤烟石油醚提取物和不同种类致香物质的含量;NPK的配施,随着施肥量的增加,烤烟石油醚提取物含量也随着增加,而致香物质含量呈现先增后减的抛物线现象.因此,N、P、K的合理配施是提高烤烟石油醚提取物和致香物质的重要措施.由田间试验结果获取的推荐施肥方案为N:P_2O_5:K_2O=1:2:3,其用量分别为75 kg/hm~2、150kg/hm~2和225kg/hm~2. 相似文献
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氨基酸和壳聚糖对烤烟生理特性及香味品质的影响 总被引：4，自引：0，他引：4
本文研究了叶面喷施氨基酸和壳聚糖对烤烟烟叶质体色素含量、酶活性的变异以及对致香物质含量的影响.结果表明:打顶后氨基酸处理烟叶叶绿素、类胡萝卜素、苯丙氨酸解氨酶(PAL)活性和脂氧合酶(LOX)活性较高,壳聚糖处理影响不显著;氨基酸处理的烟叶致香物质均比壳聚糖处理和CK高,尤其是对苯丙氨酸类、美拉德反应产物类影响显著,增幅分别达到20.9%、23.1%.壳聚糖对苯丙氨酸类致香物质有较大提高,增幅为17.6%.从整体上看,氨基酸处理调整了发育后期质体色素组分比例和相关酶类的活性,对烟叶香味品质的影响效果要好于壳聚糖. 相似文献
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Most work in horse stables is performed manually in much the same way as a century ago. It is the least mechanized sector dealing with large animals. People working with horses are exposed to several types of risk for developing musculoskeletal problems, but the work tasks and workload have not been investigated in detail. The aim of this study was to estimate the postural load of the work tasks performed around horses to find those that were harmful and required measures to be taken to reduce physical strain. Altogether, 20 subjects (stable attendants and riding instructors) were video recorded while carrying out their work in the stable, and preparing and conducting riding lessons. The work was analyzed with the Ovako Working posture Analysis System (OWAS) to determine the postural load and to categorize the potential harmfulness of the work postures. Three work tasks involved about 50% of the work positions in the three OWAS categories (AC2 to AC4) where measures for improvement are needed: "mucking out" (50%), "bedding preparation" (48%), and "sweeping" (48%). These work tasks involved over 60% work postures where the back was bent, twisted, or both bent and twisted. Therefore, it is important to find preventive measures to reduce the workload, which could include improved tools, equipment, and work technique. 相似文献
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Farm work, particularly with livestock, exposes farmers to injuries, occupational diseases, and disabling health conditions, which in many cases result in early retirement and loss of quality of life. The objectives of this study were to evaluate the prevalence of and risk factors for declined work ability among full-time dairy farmers. We conducted a postal survey using the standard Work Ability Index (WAI) questionnaire augmented with a form containing questions about working conditions and lifestyle factors that potentially affect work ability. We received 399 usable responses (245 female and 154 male; 41.5% response rate). The prevalence of declined work ability (poor or moderate WAI score) was 39% overall, 44% among females, and 32% among males. Older age, small herd size, lack of mental breaks from work, inadequate leisure, and non-use of alcohol were significantly associated with declined work ability. The odds ratios for these risk factors ranged from 2.04 to 4.67. Current injuries and diseases are part of the WAI questionnaire contributing to declined work ability. This study indicates that interventions are needed, particularly among older farmers and farmers with injuries or diseases, to restore their work ability. Life-long measures to maintain work ability are also important, preventing the steep decline in work ability currently occurring among older farmers. Based on this study, we recommend guidance addressing the identified risk factors, particularly the importance of organizing both farm and domestic work with adequate rest, leisure time, and mental breaks as counterbalance to the daily workload among livestock farmers. 相似文献
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本文分析了网络时代高校图书馆期刊工作的变化,分析了网络环境下高校图书馆期刊工作面临的机遇和挑战,探讨了网络环境下高校图书馆期刊工作改革的途径。 相似文献
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目前水土保持科技情报工作应根据科研需要，确定情报收集内容，多渠道、多途径开发情报源。在此基础上，做好二次文献工作，提高科技文献利用率，充分利用现有条件，开展情报调研。同时增强水土保持科研的情报意识，使情报工作走向社会，改善工作条件，加强信息传递速度，并优化人员组合结构，提高情报人员业务素质。 相似文献
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大学生村官工作是一项崭新的工作,在实际工作中出现了许多问题,如融入群众难、取信群众难、作用发挥难、工作开展难等普遍性的问题。针对这些情况,可将信息化作为村官工作的切入点,让大学生村官在农村信息化上发挥自己的才能,在做事中锻炼,实现激情与现实的对接。 相似文献
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Low back disorders (LBDs) continue to be a major occupational health problem facing the agricultural workforce. Working in a flexed or stooped posture is one of several workplace factors associated with occupationally related LBDs and is highly prevalent in many agricultural tasks. The purpose of this article is to evaluate the role of stooped work in the problem of LBDs among agricultural workers by examining the epidemiological literature, evaluating the scope of stooped work in agriculture, and examining current and potential intervention approaches. The literature review indicates that the prevalence of LBDs in agriculture worldwide is considerably high and substantially reported. Workers who are exposed to stooped work in agriculture are estimated to be in the 100s of millions worldwide. However, stooped work has not been specifically investigated as an independent LBD risk factor. Plausible biomechanical and physiological mechanisms of how stooped work may lead to damage to the spinal structures are discussed, and this complements the epidemiological evidence of high prevalence of LBDs in agriculture. However, this study also identifies the need to conduct more thorough epidemiological studies that utilize accurate quantitative exposure and outcome assessment techniques for developing more appropriate dose-response relationships in agricultural stooped work. This will provide better means for evaluating current and future interventions for jobs involving stooped work. Various intervention approaches are summarized to control and abate stooped work in agriculture; however, it must be emphasized that any development of ergonomic interventions for stooped work in agriculture must incorporate a participatory ergonomics approach that integrates the opinions and concerns of workers, managers, and ergonomists. 相似文献
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水土保持监督执法的实践探讨 总被引：1，自引：0，他引：1
在水土保持监督执法试点工作中。乐平市根据境内矿产资源丰富。各级工矿企业集中的特点。有针对性地开展了水保监督执法工作。走出了一条以宣传教育为基础。从引导帮助着手。综合防治狠抓难点。重在巩固的四为一体的水保监督执法路子。把监督执法和耐心细致的政治思想工作有机地结合起来,使乐平市的水土保持工作出现了“由不自觉到自觉、由自发到依法”的根本性转变。 相似文献
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杨胜权 《中国水土保持科学》2013,11(1):114-116
龙滩水电站库区移民安置工程包括众多的集镇、村寨搬迁以及交通道路新（改）建,问题复杂,矛盾突出,水土流失治理工作难度大。通过治理项目实行代管制,确保了工程顺利实施,治理成效明显。通过总结水土流失专项治理工程实行代管制的项目管理工作,阐明项目管理的创新治理模式、组织管理、理清工作重点等等,为类似项目提供借鉴和参考。 相似文献
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Bonauto DK Keifer M Rivara FP Alexander BH 《Journal of agricultural safety and health》2003,9(4):303-317
In order to estimate the one-year cumulative incidence of work-related injuries in teenage agricultural workers and to characterize the patterns and types of agricultural work performed by teenagers, we performed a community-based random-digit dialing telephone survey. We used a sampling frame of farm and non-farm households to access information on teenage agricultural workers. An agricultural community in eastern Washington State was selected due to the high number of teenage youth and its agricultural economy. Teenage agricultural workers who worked for an agricultural business owned by one of their family members were more likely to work a greater number of seasons, work fewer hours per week, perform tasks involving driving, animal care, and mechanic work, and were less likely to be seasonal workers or work in the harvest than teenagers who did not work for a family member. A similar pattern of work differences was seen when comparing non-Hispanic to Hispanic agricultural workers. Teenagers working for a family member in agriculture had a higher injury rate than teenagers working for an agricultural business not owned by a family member. The injury rate among Hispanic teenage agricultural workers was also higher than that of non-Hispanics. 相似文献