川藏铁路沿线地区夏季气温日较差的影响因素研究

利用ERA5再分析资料,分析了1979—2018年川藏铁路沿线区域气候特征.研究了2014—2018年夏季气温日较差(DTR)的变化趋势,以及2014—2018年夏季DTR与地面太阳辐射(SSR)、总降水量(TP)、总云量(TCC)、海拔(DEM)和地表平均蒸发率(MER)的相关性.结果表明:研究区域气温呈上升趋势,2...     

Experimental investigations on a forced convection solar air heater using packed bed absorber plates with phase change materials

In this work, the performance of a forced convection solar air heater was evaluated using using three packed bed absorber plate configurations and compared with flat absorber plate. The phase change material (paraffin wax) was packed in the pin-fin, trianglular and circular absorber plate configurations. The performance parameters such as, outlet air temperature, thermo-hydraulic efficiency, exergy efficiency and pressure drop were predicted and compared. The results showed that the packed bed absorber plate configurations using paraffin wax have higher outler air temperature in the range of 2–5°C with 3–40% higher thermo-hydraulic efficiency and 2–20% higher exergy efficiency when compared to flat absorber plate. However, the packed bed absorver plates have higher pressure drop when compared to flat absorber plate.     

ZnO nanoparticles induced cytotoxicity on human pulmonary adenocarcinoma cell line LTEP-a-2

Novel nanoparticles (NPs) such as zinc oxide (ZnO) NPs are widely produced and applied in our daily lives at a rapid pace. Thus, the toxicity of ZnO NPs should be monitored as an important standard for environmental risk assessment. Here we assessed the in vitro cytotoxicity of ZnO NPs on human pulmonary adenocarcinoma cells LTEP-a-2 by tetrazolium salt colorimetric assay of cell proliferation in the presence or absence of ZnO NPs. ZnO NPs-induced morphological changes in LTEP-a-2 cells were examined by light and scanning electron microscopy. The mechanism by which ZnO NPs impose the cytotoxic effect was investigated by a combination of active oxygen test, lactose dehydrogenase-release assay, and apoptosis detection. Results showed that ZnO NPs significantly inhibited the proliferation and induced evident morphological changes (cell shrinkage and chromosome condensation) in LTEP-a-2 cells. Additionally, ZnO NPs increased the level of intracellular reactive oxygen species and induced the formation of apoptotic vesicles as well as the lysis of cell nuclei. Zn²⁺ ions released from ZnO NPs into aqueous solution are important components that exert cytotoxic effects on LTEP-a-2 cells. This study provides new insights to the cytotoxicity of ZnO NPs against human health.     

Solar oxidation and removal of arsenic from water: An experimental study

Arsenic poses a significant threat to both human health and the environment. Arsenic removal through solar oxidation has been investigated in a batch process. Arsenic was artificially added to both deionized and tap water to conduct the experiments. Clean, colorless, transparent, Polyethylene Terephthalate (PET) bottles were used for Solar Oxidation and Removal of Arsenic (SORAS) experiments. Various parameters including concentration of arsenic, iron, and photo-catalyst were varied during the experiments. The maximum arsenic removal efficiency obtained was 94% and 88% for deionized water and tap water respectively when ferrous ammonium sulphate and lemon juice were used. Maximum efficiency of 88% and 82% was obtained for deionized and tap water respectively when locally available ferrous alum and glacial acetic acid were used. The change in volume of the photo-catalyst (lemon juice and glacial acetic acid) also did not affect the SORAS process significantly. Therefore, the recommended volume for the photo-catalyst was 1–2 ml/L. SORAS can very well be used for areas contaminated with arsenic having concentrations less than 100 μg/L.     

紫色光合细菌捕获太阳能的分子机理

光合作用是地球上最重要的化学反应,生物体通过它捕获太阳能,转为化学能供生长繁殖需要.光合细菌是地球上最早出现的具有原始光能合成体系的微生物,其光合反应中心是一个由多种色素分子与蛋白质以非共价键方式结合的、具有特定构象的色素-蛋白复合体-光反应中心RC(Reaction center)和LH(Light Harvesting),光能通过电荷分离及电子转移反应转化为化学能,其效率是当前人工模拟远远不能及的.本文综述了紫色光合细菌捕获太阳能的分子结构、作用机理的研究进展,并结合作者在R.sphaeroides LHII蛋白组份同源及异源基因表达方面的研究结果进行相应的分析,明确了Rhodobacter sphaeroides基因组中同源基因puc2BA的表达特点和功能,Rhodovulum sulfidophilum pucsBA与R.sphaeroides pufBA能够同时在R.sphaeroides中表达,能同时形成LHII和LHI,并具有能量传递功能.     

偏钒酸铵对小鼠血清和肝脏转氨酶活力的影响

为了考察偏钒酸铵对小鼠血清和肝脏转氨酶活力的影响,50只小鼠随机分为5组,对照组饮用三重蒸馏水,4个暴露组分别饮用剂量为5、10、15和20 mg·kg-1·d-1的偏钒酸铵,15 d后取血和肝脏样品,测定血清和肝脏中谷丙转氨酶(alanine transaminase,ALT)和谷草转氨酶(aspartate ami...     

谷胱甘肽对甲醛所致Hela细胞毒性的影响

为研究还原型谷胱甘肽(GSH)对甲醛所致Hela细胞毒性的影响,采用体外染毒方式,应用KC1-SDS法和MTT法分别检测GSH对甲醛引起Hela细胞DNA-蛋白质交联(DPC)和细胞活性的影响.结果表明,250μmol·L-1浓度下,DNA-蛋白质交联实验中甲醛染毒组所致的DPC显著高于对照组(p＜0.01),GSH+...     

太阳能热泵系统中的蓄热技术

开发新能源和节能是寻找能源出路的两大途径,太阳能热泵系统以其显著的节能性和环保性具有广阔的发展前景.论述了太阳能热泵系统中的蓄热原理和蓄热材料,介绍了实际蓄热工程,进行理论分析,指明了今后的研究与发展方向.太阳能蓄热装置的开发与应用对太阳能热泵系统的发展具有深远意义.     

DIN 75220标准阳光模拟试验与海南户外暴露试验对比研究

为了对比DIN 75220标准阳光模拟试验与我国海南户外暴露试验,以某型汽车整车和PC、PS标准板为研究对象,对自然曝晒试验和基于DIN 75220标准的整车阳光模拟试验中汽车典型部位微环境、汽车典型部件失效行为以及温度校正太阳辐射量的结果进行了对比研究。分析了2种试验方法中各统计量间的相关关系,进一步结合2种方法下的油漆件色差、内外饰件间缝隙变化结果以及关键部件典型失效问题,提出了适合用于模拟我国海南典型湿热自然环境的定制化阳光模拟试验循环。研究结果表明,基于DIN 75220标准的1个周期整车阳光模拟试验可以反映约80%的湿热自然环境整车曝晒试验3~6个月出现的失效问题。DIN 75220标准中,潮湿气候循环试验可以较好地模拟我国海南湿热自然环境,35个潮湿气候循环可以模拟海南整车自然曝晒1 a。     

吸附Sr~(2+)后酵母细胞的絮凝特性研究

为寻求生物吸附处理重金属或核素废水的后处理途径,本论文以吸附Sr2+后酵母细胞为对象,通过对絮凝前后上部液相浊度分析,探讨了絮凝剂种类、液相初始p H、酵母细胞初始浓度以及絮凝剂量等因素对絮凝效果的影响;并探讨了PAC(聚合氯化铝)对吸附Sr2+后酵母细胞的絮凝机理.结果显示:3种铝盐絮凝剂对酵母细胞絮凝效果对比结果显示为:PACKAl(SO4)2Al2(SO4)3.对PAC而言,其在实验条件下对酵母细胞的絮凝是一个快速作用过程,在1 min内出现明显矾花现象,而60 min时絮凝效率可达到99%以上.Zeta电位分析显示p H为3~10范围内,酵母细胞与PAC之间的电位差值Δζ均在50 m V以上,其中最大可达68.4 m V,这将带来PAC对酵母细胞的快速絮凝,SEM和液相电导率变化分析也证实了这点.PAC可作为一种良好的絮凝剂用于对吸附Sr2+或其他重金属离子后的酵母细胞进行絮凝处理.