环保的尴尬,谁之过?

“环境保护”早已不是什么新鲜的话题了,联合国环境计划署每年也不断颁布有关这方面的法律条款,我国及世界其它国家也都积极颁布了许多禁令并且加大了打击力度,体现出“誓死保护环境”的崇高精神,尤其是我国确定了控制人口数量、扩大绿化面积、逐步解决农村能源问题和控制污染源、治理“三废”等基本措施,甚至大力提倡不用一次性筷子、垃圾袋等。社会舆论则振奋不已。只是,我们感受到的,似乎只有环保风暴的呼啸声,不见明显效果……     

脐带绕颈的超声诊断分析与探讨

目的探讨超声诊断对胎儿脐带绕颈的诊断价值及提高诊断符合率的方法。方法对515例来本站孕期检查的妇女，根据分娩前最后一次B超检查有无脐带绕颈分成二组，对分娩结果及围产儿预后进行比较。结果脐带绕颈组羊水过少、低Apgar评分、剖宫产、死胎率均高于无脐带绕颈组。结论应用超声诊断脐带绕颈。简便易行，可为临床提供可靠依据，降低围产儿死亡率。     

大断面掘进压入式风筒最佳高度的数值模拟

为了确定大断面掘进工作面压入式风筒的最佳安设高度,采用数值模拟方法分别模拟了风筒中心距底板6 m、4.5 m、3 m、2 m以及风筒安设于洞室顶部时,通风20 min后爆破炮烟(CO)的稀释效果,并求解了各种风筒布置情况下不同断面的通风死区比例。结果表明,通风排烟效果最差的情况为风筒固定于侧帮距底板6 m时,其次为风筒固定于侧帮距底板4.5 m时,再次为风筒固定于顶部中央时,风筒固定于侧帮距底板2 m时CO在巷道内的呼吸带高度沿程浓度分布与风筒距底板3 m时差别不大,但风筒中心距底板2 m时容易造成掘进工作面上隅角炮烟和粉尘的积聚。因此,大断面掘进工作面压入风筒最佳安设高度为3 m。     

一种钢渣有压热闷处理新技术

主要从技术原理及特点、工艺过程和示范工程等方面对一种钢渣辊压破碎-余热有压热闷新技术进行系统详细地阐述,并对该技术的后续研究及推广应用前景也做了简要论述。     

PHAST软件对孔洞泄漏扩散危险区域的分析

运用PHAST软件研究泄漏孔径、风速、泄漏时间和大气稳定度对泄漏扩散面积的影响。结果表明:扩散面积随着泄漏孔径的增大、风速的增大及泄漏时间的增长而增加;大气越稳定,泄漏扩散面积越大。     

狭缝结构对船用排气引射装置气膜冷却性能影响的模拟研究

船用燃气轮机的排气温度很高,为了降低排气管道和排气烟羽的红外辐射,在排气喷管上方安装排气引射装置,利用引射原理卷吸环境中的冷空气,降低排气温度,同时在壁面上形成冷却气膜,防止壁面温度升高。排气引射装置的扩压管为多级圆环结构组成,文中利用数值计算的方法模拟了扩压管圆环间狭缝结构对壁面温度的影响,得到了壁面上的温度分布,确定了冷却气膜的长度,为扩压管的设计提供了参考。     

互动平台

上海中际能源科技有限公司诚聘英才 上海中际能源科技有限公司是专业从事企业整体节能改造、余热余压发电、热电联产以及资源综合利用等大型项目的综合性节能服务公司。为满足公司发展需要。上海中际能源科技有限公司现面向社会诚聘英才。     

石化设备堵漏安全措施

1 设备外部带压堵漏的安全措施 　　石油化工生产中,因为存在较多需要安全防范的因素,一般情况下不允许在设备上带压动火.但为了保证正常生产,在有适宜动火抢修的介质存在的同时,制定安全动火的方案,采取有效的安全措施,在确保安全的情况下可动火抢修.……     

Assessing field vulnerability to phosphorus loss in Beijing agricultural area using Revised Field Phosphorus Ranking Scheme

Guanting Reservoir,one of the drinking water supply sources of Beijing,suffers from water eutrophication.It is mainly supplied by Guishui River.Thus,to investigate the reasons of phosphorus(P)loss and improve the P management strategies in Guishui River watershed are important for the safety of drinking water in this region.In this study,a Revised Field P Ranking Scheme(PRS)was developed to reflect the field vulnerability of P loss at the field scale based on the Field PRS.In this new scheme,six factors are included, and each one was assigned a relative weight and a determination method.The affecting factors were classified into transport factors and source factors,and,the standards of environmental quality on surface water and soil erosion classification and degradation of the China were used in this scheme.By the new scheme,thirty-four fields in the Guishui River were categorized as"low","medium"or"high"potential for P loss into the runoff.The results showed that the P loss risks of orchard and vegetable fields were higher than that of corn and soybean fields.The source factors were the main factors to affect P loss from the study area.In the study area,controlling P input and improving P usage efficiency are critical to decrease P loss.Based on the results,it was suggested that more attention should be paid on the fields of vegetable and orchard since they have extremely high usage rate of P and high soil test of E Compared with P surplus by field measurements,the Revised Field PRS was more suitable for reflecting the characteristics of fields,and had higher potential capacity to identify critical source areas of P loss than PRS.     

水电站项目生态用水工程措施设计

电站引水发电以及堤坝式电站调峰运行将使坝下河段减(脱)水,调水、引水和供水等河道以外用水水利工程也将造成下游河道减(脱)水,水文将对水生生态、生产和生活用水、河道景观等产生一系列的不利影响.为维护河流的基本生态需求,水利水电工程必须下泻一定的生态流量,将其纳入工程水资源配置统筹考虑,使河流水电动能经济规模和水资源配备向"绿色"方向发展.本文以火溪河阴坪水电站为例,简述水电工程下泄生态流量确定的主要方法和下泄生态流量的工程措施设计.