为了探究Mn_(2)CrZ(Z=Al,Ga)材料的性质,预测其用途,采用基于密度泛函的第一性原理方法,用Materials Studio 6.0计算了full-Heusler合金Mn_(2)CrAl和Mn_(2)CrGa的磁性、半金属性和力学性能。通过建模和几何优化,得到了它们的最优化晶格...为了探究Mn_(2)CrZ(Z=Al,Ga)材料的性质,预测其用途,采用基于密度泛函的第一性原理方法,用Materials Studio 6.0计算了full-Heusler合金Mn_(2)CrAl和Mn_(2)CrGa的磁性、半金属性和力学性能。通过建模和几何优化,得到了它们的最优化晶格常数分别为5.77?和6.05?。在几何优化的基础上,分别计算了它们的磁性性质和力学性质,通过对能带结构图和态密度图的分析,得出如下结论:Mn_(2)CrAl为半金属亚铁磁性材料,自旋极化率为88.9%,磁性主要来自于合金内部过渡金属原子的d轨道电子的自旋贡献;Mn_(2)CrGa是普通铁磁体。展开更多
Four microorganism strains were isolated from coastal petroleum-polluted soil and sand samples of Bohai Sea oilfield; they were found to degrade marine oil spills effectively. The experimental results show that the de...Four microorganism strains were isolated from coastal petroleum-polluted soil and sand samples of Bohai Sea oilfield; they were found to degrade marine oil spills effectively. The experimental results show that the degradation efficiency of crude oil with these four strains （XT-4, SZ-1-25, B-4-9, BS-3-12） is 95.97%, 96.01%, 97.99% and 98.99%, respectively, in their optimum conditions. The characteristics of bacterial biodegradation are investigated. The simulation biotreatment of oil-contaminated beach sand, with an initial oil content of 5,664mg/kg-dry-sand, shows that the residual oil content is 2,700 mg/kg-dry-sand and 2,679 mg/kg-dry-sand after 170 days＇ treatment with two bacteria （B-4-9, BS-3- 12）, respectively.展开更多
利用桨叶干化工艺对城市脱水污泥进行处理,依托某污泥干化项目开展不同负荷工况干化运行效果的影响研究,考察了含水率、蒸汽耗量、循环载气和性质变化,并进行系统运行经济性分析。结果表明:桨叶干化是一种适于污泥处理的技术,出泥效果稳...利用桨叶干化工艺对城市脱水污泥进行处理,依托某污泥干化项目开展不同负荷工况干化运行效果的影响研究,考察了含水率、蒸汽耗量、循环载气和性质变化,并进行系统运行经济性分析。结果表明:桨叶干化是一种适于污泥处理的技术,出泥效果稳定,含水率低于30%且可调节,蒸发速率在10~20 kg H_(2)O/(m^(2)·h),具有自清洁功能能有效防止污泥粘结;蒸汽消耗系数为1.045~1.397,理论设计值可设定为1.4;循环载气量约为蒸发水量的0.78~1.27 kg/(kg H_(2)O·h);在干燥机内部干化过程中循环载气量适当增大可增加空气与污泥直接的对流换热系数,提高干化速率和减少蒸汽耗量。蒸汽成本占直接运行成本的89%,在项目实际运行过程中,在满足目标处理含水率的条件下,可根据实际项目情况通过降低运行负荷比例和增加循环载气量降低蒸汽耗量,通过设备运行参数精细化管理降低运行成本,检修时应关注干燥机中前段设备磨损和粘壁情况,以减少因污泥粘膜造成的换热损失。展开更多
文摘为了探究Mn_(2)CrZ(Z=Al,Ga)材料的性质,预测其用途,采用基于密度泛函的第一性原理方法,用Materials Studio 6.0计算了full-Heusler合金Mn_(2)CrAl和Mn_(2)CrGa的磁性、半金属性和力学性能。通过建模和几何优化,得到了它们的最优化晶格常数分别为5.77?和6.05?。在几何优化的基础上,分别计算了它们的磁性性质和力学性质,通过对能带结构图和态密度图的分析,得出如下结论:Mn_(2)CrAl为半金属亚铁磁性材料,自旋极化率为88.9%,磁性主要来自于合金内部过渡金属原子的d轨道电子的自旋贡献;Mn_(2)CrGa是普通铁磁体。
基金This work was financially supported by the National Natural Science Foundation of China (No.40472152)
文摘Four microorganism strains were isolated from coastal petroleum-polluted soil and sand samples of Bohai Sea oilfield; they were found to degrade marine oil spills effectively. The experimental results show that the degradation efficiency of crude oil with these four strains （XT-4, SZ-1-25, B-4-9, BS-3-12） is 95.97%, 96.01%, 97.99% and 98.99%, respectively, in their optimum conditions. The characteristics of bacterial biodegradation are investigated. The simulation biotreatment of oil-contaminated beach sand, with an initial oil content of 5,664mg/kg-dry-sand, shows that the residual oil content is 2,700 mg/kg-dry-sand and 2,679 mg/kg-dry-sand after 170 days＇ treatment with two bacteria （B-4-9, BS-3- 12）, respectively.
文摘利用桨叶干化工艺对城市脱水污泥进行处理,依托某污泥干化项目开展不同负荷工况干化运行效果的影响研究,考察了含水率、蒸汽耗量、循环载气和性质变化,并进行系统运行经济性分析。结果表明:桨叶干化是一种适于污泥处理的技术,出泥效果稳定,含水率低于30%且可调节,蒸发速率在10~20 kg H_(2)O/(m^(2)·h),具有自清洁功能能有效防止污泥粘结;蒸汽消耗系数为1.045~1.397,理论设计值可设定为1.4;循环载气量约为蒸发水量的0.78~1.27 kg/(kg H_(2)O·h);在干燥机内部干化过程中循环载气量适当增大可增加空气与污泥直接的对流换热系数,提高干化速率和减少蒸汽耗量。蒸汽成本占直接运行成本的89%,在项目实际运行过程中,在满足目标处理含水率的条件下,可根据实际项目情况通过降低运行负荷比例和增加循环载气量降低蒸汽耗量,通过设备运行参数精细化管理降低运行成本,检修时应关注干燥机中前段设备磨损和粘壁情况,以减少因污泥粘膜造成的换热损失。
