傍河污染场地地下水修复技术筛选

针对目前地下水修复技术方法众多,有着不同适用性和优缺点的情况,对不同的污染场地类型国内外尚未形成一套成熟的筛选机制.本文引入IOC(importance order of the criteria)筛选法,以地下水修复技术的修复成本、修复时长、技术有效性、技术可靠性、工人保护及人群保护为筛选指标,以吉林市某废弃工厂为研究区,在结合地下水污染调查和地下水人体健康风险评价的基础上确定了场地地下水的修复目标污染物,根据场地区域水文地质条件分析和目标污染物特性,结合抽出处理、曝气技术、渗透反应墙等地下水污染修复技术特点,筛选出合理的地下水污染修复方案.结果显示,场地地下水中苯并(a)芘的致癌风险超过单项污染物的可接受致癌风险限值,确定为修复目标污染物.经过IOC排序法分析确定,在有效性优先条件下,抽出-生物反应器法是理想的修复技术;在经济优先的条件下,地下水曝气技术适用于该场地的修复技术;综合有效性和经济优先2种条件,组合技术抽出-生物反应器法结合地下水曝气技术适宜于该场地的修复技术.     

浆状氢氧化镁制备

料浆状氢氧化镁是环境友好的水处理剂,广泛用作酸的中和剂,沉淀重金属离子,脱除二氧化硫。以唐山南堡盐场的卤水为原料,以氨水为沉淀剂制备了料浆状氢氧化镁,通过试验确定了卤水氨法沉镁制备氢氧化镁的最佳工艺条件。研究了分散剂的种类、加入量对料浆状氢氧化镁性能的影响,并通过实验确定了制备浆状氢氧化镁聚分散剂环氧琥珀酸合成条件和最佳配比。浆状氢氧化镁最佳分散剂配比为：偏硅酸钠加入量0．3％,烷基酚聚氧乙烯醚溶液加入量2．4％,聚环氧琥珀酸的加入量为0．7％。在该条件下制备出的产品放置三周不分层,且具有很好的流动性。     

芦根汁液救治小鼠TTX中毒试验观察

以标定的TTX提取液(1MU/mL)对ICR小鼠进行急性中毒试验,以芦根浸汁及煎汁腹注小鼠,观察其救治效果。结果表明,芦根煎汁的疗效较显著,而芦根、芦苇叶的浸汁也有一定疗效。     

Challenge and Methods of Synchronous Disk I／O

At present, I/O is the performance bottleneck limiting the speed of computer systems. A large number of I/O operations are synchronous read/write operations of only small data blocks. However, reducing the latency of synchronous I/O operation is a non-trivial problem. In this paper, we propose two methods to address this problem. The first method, FastSync, uses a cache disk optimized for write operation via use of a disk-head position prediction algorithm. In this way, disk capacity is traded for synchronous I/O performance. The second method, LND, uses free memory capacity in a network environment as a cache disk for the buffeting of synchronous I/O operation. Data integrity in FastSync is ensured by using a data log on the cache disk, whereas in LND, integrity is ensured by the storage in distributed memory of multiple copies of each data block. Both methods succeed in dramatically increasing the performance of synchronous I/O operation. The performance of LND is limited by the network speed, whereas performance of FastSync is determined mostly by the data block size.