芦笛·芦叶·芦花

早春二月,与小草一起先绿起来的要数河滩上的芦苇了。一场春雨过后,芦苇就像竹笋一样直往上窜,一天一个样子,好似在一夜之间,河边的芦苇长得就有人高了,这时河滩上是我们玩耍最多的地方。 从河滩上传出的除了我们的阵阵笑声外,就是我们吹出的没有一点节奏的芦笛声了。最初吹出的芦笛声只有自己才能听到,现在想起来那种声音也不知算不算是芦笛的声音。那时的芦苇刚刚冒尖不久,我们抽出芦苇中间嫩嫩的芦     

海底大地震

您以为只有陆地才经常发生地震吗?不,在深深的海底,也经常发生地震。据统计,全球80％的地震都集中在幽深的海底,特别是在太平洋周围海洋平均深度4000米以上,终年暗无天日的海沟里以及它附近与群岛区的深渊中尤为多见。     

图书馆消防安全--重中之重

尽管公共场所建筑物的消防安全历来是一个重要问题,国家每年都要投入很大的人力、物力来加强预防措施以避免出现人员及财产的重大损失,但终日警钟长鸣也还是存在缝隙,仅最近一个时期,各地就连续出现公共建筑物失火伤人的重大事故。因此,日常的防微杜渐工作是十分重要的。     

非煤矿山安全评价方法探讨

介绍了非煤矿山安全评价的内容和方法,分析了目前评价方法的不足和缺陷,提出了一种新型非煤矿山安全评价方法,并结合湖北某石膏矿山安全评价的实例,阐述了这种评价方法的应用过程,最后对这种方法提出改进建议。     

危险废物风险评价与管理

从危险废物风险评价的基本含义人手,在讨论了危险废物风险评价应遵循的原则和评价依据基础上,就危险废物风险评价方法、评价内容和评价程序等内容进行了探讨。在参考相关参数和模型的基础上重点论述了危险废物风险评价参数的选择和模型。最后提到了危险废物风险评价的管理,提出了一种风险管理体系。     

Reconsideration on the effect of nitrogen on mixed culture polyhydroxyalkanoate production toward high organic loading enrichment history

Effect of nitrogen on mixed culture PHA production was reconsidered. Enrichment history of PHA accumulating culture was discussed. Higher PHA content and biomass growth were achieved in presence of nitrogen. Enrichment strategy toward higher PHA accumulation was investigated. Microbial community succession in PHA accumulation phase was investigated. In most of the operating strategies for mixed microbial cultures polyhydroxyalkanoate (PHA) production, moderate organic loads and low nitrogen concentrations are used, however, the real waste streams contain variable concentrations of carbon and nitrogen. To evaluate the effect of enrichment history on PHA producer and production the various carbon and nitrogen levels were utilized during the accumulation phase. Different operating strategies were applied in three sequencing batch reactors (SBRs) subjected to aerobic dynamic feeding. The maximum PHA production of the enriched cultures under nutrient excess, limitation and starvation (Cmol/Nmol ratio of 8, 40 and ∞, respectively) was evaluated in batch assays. A higher PHA content and biomass growth were achieved in the nutrients presence in comparison to the nutrient starvation condition. The cultures from the SBR treated under short sludge retention time, high organic loading rate, short cycle length (SBR#3) and nutrient excess reached the maximum PHA content (54.9%) and biomass increase (38.9%). Under nutrient limitation, the negative biomass growth was observed under nutrient starvation because of the sampling loss. The succession of microbial communities in SBRs and batch assays was analyzed using terminal restriction fragment length polymorphism. The SBR#3 had the best overall PHA production performance considering its high PHA content and productivity in all nutrient content, it indicates that nitrogen has a substantial impact on PHA yield especially when high organic loading rate enrichment history is involved.     

真空联合堆载预压加固长江漫滩相软基孔压测试分析

结合长江江苏镇江段某码头堆场地基采用真空联合堆载预压法加固处理工程,通过现场钻孔埋设孔隙水压力计,对长江漫滩相软土地基加固过程中孔隙水压力的发展变化过程进行了测试分析。结果表明:真空预压区,加固30d后地基中孔隙水压力变化基本稳定,且土中超静孔隙水压力的消散受该深度排水板中真空荷载的影响十分显著;排水板中真空荷载随深度衰减,衰减速率与排水板周围土层性质密切相关;通过现场测试得到排水板周围为长江漫滩相淤泥质粉质黏土时,真空荷载沿排水板深度衰减速率约为3kPa/m。