污染农田土壤修复产业发展面临的问题及建议

随着经济的发展,我国的农业建设也迎来了新的发展机遇,但是目前我国的农业发展过程中存在着严重的土壤污染问题,污染农田土壤修复的问题有待解决。本文围绕污染农田土壤修复这一问题展开研究,望有所助益。     

典型电脱盐废水预处理技术及其应用

针对原油电脱盐废水处理形势日益严峻的问题,介绍了电脱盐废水预处理技术的研究及应用进展,分析了电脱盐废水预处理技术的原理、特点及应用效果,总结了影响电脱盐废水特点的主要因素,指出改进原油开采技术、提高电脱盐装置的运行和管理水平可从源头上改善电脱盐废水水质,进一步开发和应用先进技术对控制电脱盐废水污染具有积极意义。     

浅谈特种飞机任务电子系统大修

随着任务电子系统在飞机领域的广泛应用,出现了一些以任务电子系统功性能为主要作战指标的特种飞机,如预警机、电子干扰机、侦察机、指挥通信机等,其载机大修在国内已经有一套成熟的标准和体系,但是任务电子系统的大修还是空白篇幅,没有相关的指导依据,本文为特种飞机任务电子系统大修的必要性、修理周期、目的、方法提供指导性建议。     

Validation of Bacteroidales-based microbial source tracking markers for pig fecal pollution and their application in two rivers of North China

• Pig feces is the predominant excrement produced by animal husbandry in China. • The PF, Pig-1-Bac^TaqMan, and Pig-2-Bac^TaqMan MST assays showed better performance. • The pig-specific MST assays can contribute to managing the pig fecal pollution. In China, pig feces is the predominant source of excrement produced by animal husbandry. Improper use or direct discharge of pig feces can result in contamination of natural water systems. Microbial source tracking (MST) technology can identify the sources of fecal pollution in environmental water, and contribute to the management of pig fecal pollution by local environmental protection agencies. However, the accuracy of such assays can be context-dependent, and they have not been comprehensively evaluated under Chinese conditions. We aimed to compare the performance of five previously reported pig-specific MST assays (PF, Pig-Bac1^SYBR, Pig-Bac2^SYBR, Pig-1-Bac^TaqMan, and Pig-2-Bac^TaqMan, which are based on Bacteroidales 16S rRNA gene markers) and apply them in two rivers of North China. We collected a total of 173 fecal samples from pigs, cows, goats, chickens, humans, and horses across China. The PF assay optimized in this study showed outstanding qualitative performance and achieved 100% specificity and sensitivity. However, the two SYBR green qPCR assays (Pig-Bac1^SYBR and Pig-Bac2^SYBR) cross-reacted with most non-pig fecal samples. In contrast, both the Pig-1-Bac^TaqMan and Pig-2-Bac^TaqMan assays gave 100% specificity and sensitivity. Of these, the Pig-2-Bac^TaqMan assay showed higher reproducibility. Our results regarding the specificity of these pig-specific MST assays differ from those reported in Thailand, Japan, and America. Using the PF and Pig-2-Bac^TaqMan assays, a field test comparing the levels of pig fecal pollution in rivers near a pig farm before and after comprehensive environmental pollution governance indicated that pig fecal pollution was effectively controlled at this location.     

基于遗传算法的袋式除尘器脉冲喷吹清灰自适应模糊控制

针对当前主流的袋式除尘器定时、定压差脉冲喷吹清灰控制技术所表现的控制效果不理想、压缩空气消耗高以及无法自动调节清灰周期等问题,提出了一种基于控制规则可调的脉冲喷吹清灰自适应模糊控制方法。研发了一种脉冲喷吹清灰控制结构模型及自适应模糊控制器,将模糊控制规则按阻力偏差的大小分为4个等级并分别引入调整因子,以阻力偏差的时间误差绝对值积分(ITAE)作为目标函数,通过遗传寻优得到最优调整因子,进而得到能够根据不同工况条件自适应调节清灰周期的模糊控制规则。实验结果表明:相较于优化前的模糊控制器,该自适应模糊控制器超调量小、响应速度提升39.5%;与定时、定压差控制相比,自适应模糊控制能够维持过滤阻力的稳定性,分别节省耗气量34.0%、5.4%。在脉冲喷吹清灰控制系统中,该自适应模糊控制方法使控制效果得到较大提高。     

考虑儿童运动特性的小学教学楼楼梯间人员疏散研究

为研究小学教学楼楼梯间人员运动行为以及影响人员疏散的因素，开展人员疏散实验并构建疏散模拟场景。基于疏散实验研究不同实验场景的出口流量和人员运动速度，通过疏散仿真模拟，分析不同人员运动速度、人员数量及疏散策略对疏散的影响。结果表明:排队下楼的人员运动速度比紧急疏散人员低22.7%，自由上楼人员运动速度比排队上楼人员高8%；人员总疏散时间随人员运动速度的增加而降低，但总疏散时间随速度增加而降低的幅度变小；加入分层疏散策略会增加人群疏散总时间，但整个疏散过程人员分布均匀，在建筑瓶颈不易产生人员过度拥挤现象，因而在疏散过程中应适当采用分层疏散策略。     

石油化工企业含苯胺消防污水处理技术研究

针对石油化工企业含苯胺的消防污水,利用基于过氧化氢和氯化铁为氧化剂的深度氧化技术,通过氧化、絮凝、过滤和吸附对消防污水进行处理。实验确定氧化剂的投加量为理论投加量,氧化时间1.0h,消防污水pH值为6.86时,絮凝剂最佳使用浓度约为2%,消防污水中苯胺和COD去除率达到99.5%以上,达到了消防污水处理效果。     

Abundance and removal of antibiotic resistance genes (ARGs) in the rearing environments of intensive shrimp aquaculture in South China

Although research regarding antibiotic resistance genes (ARGs) in aquaculture environments has gained increasing scientific interest, further studies are required to understand the abundances and removal mechanisms of ARGs during the entire rearing period of shrimp aquaculture. Thus, in this study, abundances, distributions and removal rates of ARGs in different environmental compartments of intensive shrimp farms in South China were investigated during the entire rearing period. The results indicated that sul1 and cmlA were the predominant ARGs in the water and sediment samples. Additionally, the total abundance of ARGs was higher in shrimp pond water than in the source water and farm effluent. Moreover, sediment samples indicated significantly higher ARG abundances than water samples from the shrimp ponds (P?<?0.05). Environmental factors were found to significantly affect the distribution of ARGs in shrimp rearing environments. Furthermore, stable ponds aided the removal of ARGs from shrimp pond water. This study accounted for temporal variations in ARG abundances as well as removal of ARGs in different environmental compartments during the entire shrimp rearing period. However, additional research is required to optimize the water treatment process for removal of ARGs from the aquaculture.     

2000～2015年山地城市土地利用景观格局动态演变研究——以重庆市渝北区为例

以重庆市渝北区为例，借助地理信息系统和遥感手段，利用Landsat TM 遥感数据和DEM数据，采用景观指数分析、地形位指数和分布指数等计算方法，对渝北区 2000、2005、2010 和 2015 年土地利用景观格局变化特征进行了分析，着重探讨了不同地形、坡度下各种景观类型变化情况，以及它们之间的相互关系，以期为在相似条件下的城市最佳土地利用模式选择提供一定的借鉴和参考。结果表明：（1）渝北区土地资源以中、高级地形位为主，海拔 200 m 以下，坡度6°以下的土地资源比较匮乏；（2）渝北区主要的景观类型是耕地和林地，但耕地景观总的趋势是不断减少，林地不断增加，建设用地增长较快，总体上景观破碎化程度在增加，景观多样性呈上升趋势；（3）研究期内，中低级地形位区间内大量耕地转变为建设用地，林地、草地景观面积的分布趋势随着地形位指数成正相关关系，其优势地形位主要集中于高级别地形位区间。     

嘉陵江有毒鱼类的分布研究

为了丰富人们对有毒鱼类的认知,结合8年的调查数据和已有资料对嘉陵江中有毒鱼类的种类、分布和食性进行研究。研究结果发现:在嘉陵江中有毒鱼类共计18种,隶属于4目6科17属,随着分类水平的变化(从目、科、属到种),有毒鱼类在不同分类级别下所占的比例逐渐降低。嘉陵江有毒鱼类中仅圆口铜鱼(Coreius guichenoti)和鳜(Siniperca chuatsi)分布于中下游,其余16种有毒鱼类分布于整个嘉陵江干流。Jaccard’s相似性分析表明各江段有毒鱼类分布的相似性极高,卡方(χ~2)检验结果显示各江段有毒鱼类分布无显著性差异(p0.05)。嘉陵江分布的有毒鱼类共4类,包括卵毒鱼类2种,血清毒鱼类1种,胆毒鱼类9种以及刺毒鱼类7种,其中鲇(Silurus asotus)既属于卵毒鱼类也属于刺毒鱼类,胆毒鱼类全部来源于鲤科鱼类,暂没有发现皮肤黏液毒鱼类。这18种有毒鱼类共包含7种食性类型,主要以杂食性和肉食性类型为主,分别占有毒鱼类种类数的38.89%和33.33%。通过本研究可知,有毒鱼类在嘉陵江中分布广泛,有毒鱼类种类和类别较多。该研究促进了人们对嘉陵江有毒鱼类相关知识的了解,为进一步研究嘉陵江有毒鱼类奠定了基础。