急性有机磷农药中毒几个特殊问题的探讨

急性有机磷农药中毒是急诊医学救治的重要疾瘸之一,虽然近几年有不少进展,但仍然存在不少问题仍待研究和探讨.现就其几个特殊问题作进一步论述.1急性有机磷农药中毒院前急救急性有机磷农药中毒死亡率高,许多病人来不及去医院抢救就死亡在院外.这样的病人在院前没有进行必要的急救措施,或所     

BMED 解离硫酸盐高效清洁制酸碱工艺

 随着工业生产的快速发展,工业废水的排放量迅猛增加,其中大部分工业废水中都含有硫酸盐,硫酸盐的过量排放会对环境水体造成严重的污染与破坏。本研究以硫酸钠废液为原料,采用双极膜电渗析(BMED)新型工艺,实现含硫酸盐废水的回收再利用,高效、清洁地制取酸、碱。实验主要考查了电流密度、原料液浓度及初始酸碱浓度对膜堆性能的影响,并对两种离子交换膜的性能进行对比。结果表明,实验范围内,氢氧化钠的收率高达84.08%,平均电流效率为54%,能耗为5.29 kW·h/kg;氢氧化钠收率和过程能耗均随电流密度的增大而增加;电流密度恒定时,较高的原料液浓度可使膜堆电阻维持在较低的水平,进而降低能耗;适量加入初始酸碱能够降低能耗,但也会降低电流效率。     

大学生体育与健康意识的调查研究

通过问卷调查法和文献资料研究法，对高职高专大学生的体育与健康意识进行了调查，结果表明占80％的学生对体育有良好的认知态度，并能充分地认识到提高身体素质的重要性；在健康意识方面大一和大二的学生呈上升趋势，大二达到最高，大三则是随着年级的升高而有所下降，并与所学的专业存在明显的相关性．对健康问题的关注和投入与他们对健康的良好认知不相符合。     

从“铁”说起

钢和铁是一对＂孪生兄弟＂,都含有铁元素,但含碳量有差异。铁锅通常由生铁制成,含碳量在2%以上;炒菜用的铁勺很轻盈、柔韧,是由熟铁做成的,含碳量通常低于0.02%。当含碳量控制在0.02%至2.04%之间时,铁就变成了韧性与硬度俱佳的钢。厨房里锋利的菜刀就是用钢做的。     

ADSORPTION OF SHORT TWO-DIMENSIONAL COMPACT CHAINS

Short two-dimensional compact chains adsorbed on the attractive surface at different temperatures were investigated by using the enumeration calculation method. First we investigate the chain size and shape of adsorbed chains, such as characteristic ratios of mean-square radii of gyration 〈S^2〉x/N and 〈S^2〉y/N, shape factor 〈δ〉, and the orientation of chain bonds 〈cos^2 θ〉 to illuminate how the size and shape of adsorbed compact chains change with increasing temperatures. There are some special behaviors for the chain size and shape at low temperature, especially for strong attraction interaction. In the meantime, adsorbed compact chains have different behaviors from general adsorbed polymer chains. Some thermodynamics properties are also discussed here. Heat capacity changes non-monotonously, first increases and then reduces. The transition temperature Tc is nearly 1.0, 1.4, 2.0 and 4.2 （in the unit of To） for the case of ε = 0, -1, -2 and -4 （in the unit of kTo）, respectively. Average energy per bond increases while average Helmholtz free energy per bond decreases with increasing temperatures. From these two thermodynamics parameters we can also get another transition temperature Tc＇, and it is close to 0.7, 1.1, 1.5 and 3.4 for ε= 0, -1, -2, and -4, respectively. Therefore, Tc is greater than Tc＇ under the same condition. These investigations may provide some insights into the thermodynamics behaviors of adsorbed protein-like chains.