Driving factors of the flushing time of bays formed where tributaries enter a reservoir

Flushing time is an integrative parameter that can represent water exchange capacity and sensitivity to pollution threats. As bays formed where tributaries enter the Three Gorges Reservoir of China have experienced frequent algal blooms over the past decade, we examine the spatially variable flushing time of a typical tributary bay (Xiangxi Bay) by numerical tracer experiments. First, the tracer concentration reduction could be approximated well by a double exponential decay curve, and the local flushing time of Xiangxi Bay is determined using key flushing coefficients. Second, a sensitivity analysis is performed to examine the influence of upstream inflow, temperature difference, wind, water level of the reservoir, and daily water level fluctuation on the spatial variation in local flushing time. Finally, according to local flushing time values and the sensitivity analysis results, the bay can be generally characterized by three zones: riverine, transitional, and mainstream‐influenced zones. In particular, the local flushing times in the riverine zone are mainly affected by the upstream inflow. The difference in temperature between the reservoir mainstream and Xiangxi Bay is the main forcing in the transitional and mainstream‐influenced zones. This study is the first to investigate different driving factors for flushing time in a typical reservoir tributary bay. The findings provide insights on the transport processes in such water bodies, suggesting the possibility of using the longitudinal zonation of flushing time for reservoir management.     

Expression and Characterization of Bioactive Recombinant Human α-Lactalbumin in the Milk of Transgenic Cloned Cows

Improvement of the nutritional value of cow milk with transgenic expression of recombinant human α-lactalbumin (α-LA) has been previously attempted. However, the detailed characterization of the recombinant protein and analysis of the transgenic milk components are not explored yet. Here, we first report production of healthy transgenic cows by somatic cell nuclear transfer, in which expression of up to 1.55 g/L of recombinant human α-LA was achieved. The recombinant human α-LA was purified from transgenic milk and displayed physicochemical properties similar to its natural counterpart with respect to molecular weight, structure, and regulatory activity for β-1,4-galactosyltransferase. Additionally, no N-glycosylation was found in the recombinant human α-LA, whereas the endogenous bovine α-LA was glycosylated at the unusual site ⁷¹Asn-Ile-⁷³Cys. Compared with milk from nontransgenic cows, expression of the transgene did not materially alter milk composition, such as fat and protein content. Our research thus provides scientific evidence supporting the feasibility of humanizing cow milk.     

Quantum Chemical Calculations of the Structure,Property and Stability of Penta-coordinated Carbonium Ions Derived from Normal Butane

The structure and energy of the carbonium ions formed upon protonation of butane were studied by the DFT methods. Four stable structures are identified for the protonated form of n-butane,the energy increases in the following order:C2HC3C1HC2>C2HH>C1HH. The stability of the penta-coordinated carbonium ions may be explained by the electron distribution in the three-center-two-electron bonds. The delocalization of the penta-coordinated ...     

鄂尔多斯盆地塔巴庙地区上古生界源岩热演化特征

鄂尔多斯盆地北部主力气源岩太原组、山西组煤系地层热成熟史的研究对本区天然气充注过程和有利目标区预测具有重要的参考价值。在对研究区烃源岩评价和一维、二维地质建模研究的基础上,利用BasinMod盆地模拟软件对单井以及研究区内二维剖面、平面进行了煤系烃源岩热演化史模拟研究。研究结果表明:(1)该区在中三叠世进入生烃门限,中侏罗世以后,烃源岩持续埋深,早白垩世末期至最大埋深(4000 m左右),绝大多数的天然气都在这一阶段生成,早白垩世末构造抬升以后只有少量天然气生成;(2)研究区上古生界太原组和山西组煤系源岩最大累积生烃强度可达到2200×108m3/km2,对现今天然气的分布具有较强的控制作用。     

电解氧化水在瓶装饮用纯净水生产过程中消毒效果研究

为建立一种新的瓶装饮用纯净水的消毒方法,利用消毒产品鉴定与监测实验技术规范中的实验方法,对电解氧化水在瓶装饮用纯净水生产过程中几个主要环节的消毒效果作了实验研究。结果显示,电解氧化水浸泡600mL纯净水包装瓶1、2、5、10min,对其中污染的细菌的杀灭率分别为98．58％、99．06％、99．60％和99．92％,对污染真菌的杀灭率分别为97．34％、98．48％、99．65％和99．99％;用电解氧化水冲洗生产设备,对其表面污染细菌和真菌的杀灭率分别为95．73％和96．30％;用电解氧化水洗手,工作人员手污染的细菌和真菌分别减少93．84％和96．43％;用电解氧化水喷雾生产车间,空气中的细菌和真菌分别下降50．98％和53．49％;由于电解氧化水具有低毒无残留等优点,很适合在食品卫生领域推广应用。     

MgO/AC催化剂的表征及其在对异丁基苯乙酮氢转移反应中的性能

通过浸渍法制备了MgO/活性炭(AC)催化剂,采用XRD、N2吸附-脱附、XPS和CO2-TPD等方法对催化剂进行表征,考察了MgO/AC催化剂在以异丙醇为氢源的对异丁基苯乙酮氢转移生成1-(4-异丁基苯基)乙醇反应中的催化性能,并与MgO催化剂进行对比。实验结果表明,MgO/AC催化剂因MgO分散度提高使碱中心数目增加,以及π电子的相互作用使催化剂活性中心附近的对异丁基苯乙酮浓度增大,这两方面的原因使MgO/AC催化剂比MgO催化剂具有更高的氢转移活性;对异丁基苯乙酮氢转移反应的适宜反应条件为:10.0%MgO/AC催化剂用量(以对异丁基苯乙酮为基准)为0.15 g/mmol、n(异丙醇):n(对异丁基苯乙酮)=10:1、82℃、4 h,在此条件下对异丁基苯乙酮转化率达到80%以上。     

催化裂化回炼油加氢精制反应规律研究

通过考察工艺条件对催化裂化回炼油加氢精制反应的影响,得到加氢精制油中不同烃类以及S、N质量分数随工艺条件的变化规律。结果表明：链烷烃及环烷烃质量分数随工艺条件变化不明显;增加氢油体积比、反应时间、氢分压均可促进HDA,HDS,HDN反应进行,但当超过最佳氢油体积比时,继续增加氢油体积比,HDA,HDS,HDN反应效果基本保持不变;提高反应温度有利于HDS反应的进行,而由于热力学平衡限制,HDA、HDN反应均存在一个最佳反应温度,且HDN反应的最佳反应温度较HDA反应高;在相同加氢精制条件下,不同结构的多环芳烃有不同的加氢饱和活性,迫位缩合型多环芳烃较渺位缩合型多环芳烃难加氢。     

氧化铝催化合成马来酸二辛酯

首次将氧化铝用于催化合成马来酸二辛酯。最佳条件,塑酐摩尔比为３．０：１,氧化铝用量为酐质量的４％,回流反应１ｈ,转化率达９９．５％,收率为８８．１％,该催化剂价廉易得,可循环使用多次,不污染环境。     

螺旋管中间介质气化器可行性研究

A novel intermediate fluid vaporization (IFV) technology for LNG re-gasification process with spiral-wound heat exchanging tubes is proposed. The new IFV project combines the advantage of running the shell and tube heat exchangers at high pressure with the advantage of compact space of heat exchangers. Thermal analysis on the two processes of forced convection and vaporization type heat transfer in the spiral wound tubes and vapor condensation /re-boiling type of heat transfer via intermediate fluid in shell side shows the feasibility of this promising technology.     

Case study and theoretical analysis of a solar driven two-stage rotary desiccant cooling system assisted by vapor compression air-conditioning

In this paper, a solar hybrid desiccant air conditioning system, which combines the technologies of two-stage desiccant cooling (TSDC) and air-source vapor compression air-conditioning (VAC) together, has been configured, experimentally investigated and theoretically analyzed. The system mainly includes a TSDC unit with design cooling capacity for 10 kW, an air-source VAC unit with 20 kW in nominal cooling capacity, a flat plate solar collector array for 90 m², a hot water storage tank and a cooling tower. Performance model of the system has been created in TRNSYS simulation studio. The objective of this paper is to report the test result of the solar hybrid air conditioning system and evaluate the energy saving potential, thereby providing useful data for practical application. Experimental results show that, under typical weather condition, the solar driven desiccant cooling unit can achieve an average cooling capacity of 10.9 kW, which contributes 35.7% of the cooling capacity provided by the hybrid system. Corresponding average thermal COP is over 1.0, electric COP is up to 11.48. Under Beijing (temperate), Shanghai (humid) and Hong Kong (extreme humid) weather conditions, the solar TSDC unit can remove about 57%, 69% and 55% of the seasonal moisture load, thereby reducing electric power consumption by about 31%, 34% and 22%, respectively. These suggest that the solar hybrid system is feasible for a wide range of operating conditions.