环境微生物技术在处理医院污水中的应用

我国每年产生大量医院污水,其中包含病原体等多种污染物,是危害人类健康的重要隐患.目前对医院污水的处理主要包括污水的预处理、生物处理和消毒三部分.通过采用活性污泥法、生物接触氧化法、膜生物反应器、曝气生物滤池法等环境微生物技术对污水进行处理,从而有效去除水中的有机物,破坏病原微生物赖以生存的物质基础和保障消毒效果.不同的处理工艺各有优缺,适合于不同规模的医院

红树林土壤中脂肪酶产生菌的筛选及酶学性质

从福建龙海红树林区土壤中分离获得9株产脂肪酶的细菌,经16S rDNA序列分析表明分别属于红球菌属(Rhodococcus)、库克菌属(Kocuria)、假单胞菌属(Pseudomonas)、芽胞杆菌属(Bacillus)和微小杆菌属(Exiguobacteri-um).对9株细菌所产的脂肪酶进行酶学性质研究,结果显示这些酶的最适作用温度在25~35℃、最适作用pH值在8~10,其中L13菌株所产脂肪酶(L′13)具有适应温度和pH范围较广、对多种金属离子耐受性强、能有效降解不同底物等特点,在环境保护和工业生产方面具有良好的应用前景

湖南目平湖钉螺血吸虫病原生物控制资源调查及感染试验

目的虽然一种贝类可作数种吸虫的中间宿主,但在各吸虫种类都存在的一自然环境中,它们共同贝类宿主的一个体通常只携带一种吸虫幼虫期。作者利用这一规律在湖南汉寿目平湖血吸虫病区进行媒介钉螺的调查,查到钉螺感染有日本血吸虫(Schistosoma japonicum)、外睾类吸虫(Exorchis)、斜睾类吸虫(Plagiorchis)、侧殖类吸虫(Asymphylodora)和背孔类吸虫(Notocotylus)5种吸虫的幼虫期。其中对生物控制媒介钉螺有利用价值的外睾类吸虫,其钉螺感染率为3.298%(96/2911),终宿主鲶鱼(Parasilurus asoyus)的感染率为99.31%(434/437)、平均每尾鲶鱼的感染强度为115.4条。先用外睾类吸虫虫卵感染钉螺后再感染日本血吸虫毛蚴,切片观察不同时间的实验螺,后侵入的血吸虫幼虫,全部受损害不能发育

基于mppic方法改进emmsdp曳力模型

改进了面向离散粒子法的能量最小多尺度曳力模型(EMMS/DP)的颗粒参数生成方式,并将非均匀因子(HD)与固相浓度和滑移速度关联以考虑介尺度结构动态效应的影响,用改进的EMMS/DP模型与多相流质点网格模型(MP-PIC)耦合模拟气固两相流提升管系统,模拟结果与实验值吻合很好,考察了MP-PIC方法的网格无关性和粗粒化模型参数

基于MP-PIC方法改进EMMS/DP曳力模型

改进了面向离散粒子法的能量最小多尺度曳力模型(EMMS/DP)的颗粒参数生成方式,并将非均匀因子(HD)与固相浓度和滑移速度关联以考虑介尺度结构动态效应的影响,用改进的EMMS/DP模型与多相流质点网格模型(MP-PIC)耦合模拟气固两相流提升管系统,模拟结果与实验值吻合很好,考察了MP-PIC方法的网格无关性和粗粒化模型参数

中国科学院力学研究所高温气体动力学国家重点实验室;

弹道靶与风洞类设备相比有洞壁干扰小、无模型支撑干扰、不存在流场品质好坏的问题,能够实现7~8km/s真实飞行速度等优点。因此在冲击动力学、目标特性和再入物理学等研究中,具有不可替代的作用。弹丸要达到超高速的飞行,弹道靶的发射装置通常为二级气炮,它是由两座一级炮串联而成,通过活塞把第一级炮的驱动能量传给第二级炮。第一级驱动通常采用火药爆燃和压缩气体两种方式,前者驱动能力明显大于后者,但火药的使用受到严重限制。本文采用气体爆轰驱动的方法,开展了一级炮活塞运动规律的数值计算和试验验证。初步研究结果表明,气体爆轰驱动明显大于压缩空气,氢氧(3H2/O2)混合气体初始压力仅为10bar,爆轰后可使750..

Effects of changes in precipitation on soil respiration in coastal wetlands of the Yellow River Delta

Soil moisture fluctuation caused by changes in precipitation patterns associated with global change is an important driving force for the dynamic changes of soil respiration. However, it is unclear how coastal wetlands respond to changes in precipitation patterns, and thus cause changes in the ecosystem blue carbon function. To explore the response and mechanism of soil respiration and environmental and biological factors to precipitation changes, the soil carbon flux observation system was applied to monitor wetland soil respiration rates under different precipitation treatments relying on increased and decreased precipitation fields outside the control experiment platform of the Yellow River Delta coastal wetland in 2017. The results showed that: (1) with increased precipitation, the wetland soil temperature gradually decreased; simultaneously,both precipitation increase and decrease significantly increased wetland soil moisture (P &lt; 0.05); (2) changes in precipitation significantly affected vegetation species composition, aboveground and belowground biomass allocation, and root/shoot ratio (P &lt; 0.05). A 40% and 60% precipitation increase significantly increased the wetland plant species and vegetation root shoot ratio; however,it significantly reduced the aboveground biomass of wetland vegetation. In addition,a 40% increase and 60% decrease of precipitation significantly increased the aboveground biomass of wetland vegetation; (3) there was no significant effect of precipitation changes on annual soil respiration in wetlands. Nevertheless,a 60% and 40% precipitation increase both significantly increased the soil respiration rate in wetlands during the non-flooding season (P &lt; 0.05); (4) the wetland soil respiration and moisture showed a quadratic curve (P &lt; 0.05) with the correlation coefficient decreasing with precipitation increase. Furthermore, during the wetland non-flooding season, soil respiration and temperature were exponentially correlated (P &lt; 0.05) with soil temperature sensitivity (Q10) increasing with increasing precipitation. There was no significant correlation between soil respiration and temperature during flooding periods; (5) during the flooding period,the soil respiration rate was inversely correlated with the surface water level (P&lt; 0.001).</p

High Density LiFePO_4/C Synthesized by Controlled Crystallization and Microwave Carbon Thermal Reduction

应用控制结晶法从溶液相制备球形FePO4.xH2O,再高温烧结得到FePO4前驱体,最后用微波碳热还原法合成高密度L iFePO4/C.由XRD和SEM表征该材料的结构、形貌,并测试其电化学性能.The spherical FePO_(4)·xH_(2)O was prepared in the solution by controlled crystallization.The precursor FePO_(4)was obtained in high temperatureceramic approach,then the high density LiFePO_(4)/C was synthesized by microwave carbon thermal reduction.The structure and morphology of the materials were characterized by means of XRD and SEM techniques,and the electrochemical properties were studies by charge-discharge experiments.作者联系地址：清华大学核能与新能源技术研究院,清华大学核能与新能源技术研究院,清华大学核能与新能源技术研究院,清华大学核能与新能源技术研究院,清华大学核能与新能源技术研究院,清华大学核能与新能源技术研究院 北京102201,北京102201,北京102201,北京102201,北京102201,北京102201Author's Address: Institute of Nuclear and New Energy Technology,Tsinghua University,Beijing 102201,Chin