微藻光生物反应器内辐射传输特性研究

基于有限体积法和米氏方程,本文研究了一维和二维平板气升式反应器内,入射光分别为平行光和漫射光时,反应器内藻类密度以及气泡体积率对反应器内投射辐射力分布和制氢率的影响。研究发现,当反应器内只有藻类且吸收占优时,平行光入射时投射辐射力近似按Beer定律衰减,衰减率小于漫射光。当有气泡存在时,平行光入射条件下投射辐射力衰减不能简单按Beer定律考虑,尤其是当反照率较大时。同时,在平行光入射反应器的情况下,反应器内藻类制氢率大且有效光合作用区大,更有利于藻类制氢。     

Kantorovich型Meyer-Knig-Zeller算子的点态逼近定理

1引言1960年Meyer-Knig W.和Zeller K.在[6]中提出了Meyer-Knig-Zeller算子     

液相色谱-串联质谱法测定葡萄中链霉素和双氢链霉素

研究系统地优化了样品前处理过程及仪器分析中影响链霉素和双氢链霉素残留分析准确度与响应灵敏度的各主要因素,建立了葡萄中链霉素和双氢链霉素残留的快速精准定量分析方法。葡萄样品经磷酸溶液(pH=2)超声提取、Oasis HLB单固相萃取柱富集净化后,采用Waters HSS T3色谱柱(100 mm×2.1 mm, 1.8 μm)分离,柱温35 ℃,进样量2 μL,以0.1%甲酸水溶液-甲醇溶液(60∶40, v/v)为流动相进行等度洗脱,在正离子、电喷雾电离源多反应监测模式下测定,外标法定量。链霉素和双氢链霉素在2~400 μg/L质量浓度范围内线性关系良好,相关系数(R²)分别为0.9991和0.9997;在5、10、20和40 μg/kg 4个添加水平下的平均回收率为76.8%~91.9%,相对标准偏差为0.4%~10.2%;链霉素和双氢链霉素的检出限(LOD)为1 μg/L,定量限(LOQ)为5 μg/kg。为验证该方法的适用性,将方法适用于无籽红提、新郁葡萄、夏黑葡萄等实际样品中进行添加回收实验,链霉素和双氢链霉素的平均回收率分别为77.2%~83.9%和70.8%~78.9%, RSD为3.0%~15.6%。该法的准确度和精密度均符合葡萄中链霉素和双氢链霉素分析要求,且操作简便、准确,灵敏度高,适用于葡萄中链霉素和双氢链霉素残留量的检测分析。     

磷脂在膜结构间的交换:温度和离子强度的影响

磷脂跨膜交换对生物膜功能与药学研究有重要意义.石英电子微天平及耗散系数测量仪被用于研究囊泡与支撑膜间磷脂的交换行为.研究表明:首先,在磷脂跨膜输运过程中,热力学环境和离子强度对支撑膜表面吸附囊泡的形变程度影响较小,囊泡与支撑膜的总接触面积直接取决于囊泡的吸附数量;其次,交换过程中膜结构间最大总接触面积随着温度的升高和离子强度的降低而增大,温度和离子引起的囊泡吸附速率和跨膜交换速率的变化在其中发挥着关键调节作用.本研究有助于加深对磷脂在生理条件下跨膜输运过程的理解,并为基于脂质体的药物载运体系研究提供参考.     

基于一维间距调制型光子晶格的光传输现象

采用数值模拟方法研究了高斯光束在四种间距调制型光子晶格中的传输规律. 研究发现: 在具有两个正双曲正割势垒和矩形势垒的晶格阵列中, 光波在势垒处发生明显的衍射现象, 而在势阱处发生强烈的局域现象; 在具有两个负双曲正割势垒和负矩形势垒的晶格阵列中, 光波可在势垒处发生无反射传输或在势垒中发生局域现象; 而在势阱中振荡衰减传输. 研究还发现在低功率情况下, 负势垒支持的线性模式间可以发生振荡耦合; 高功率非线性情况下, 光波将发生局域现象. 研究结果为利用光子晶格调节和控制光波传输, 实现全光开关提供了新的思路和方法. 关键词： 调制型光子晶格 波导阵列 模式 光开关     

位置-尺度分布族中均值-方差准则与期望效用理论的一致性

证明了当决策集为位置-尺度分布族时,期望效用理论与均值-方差准则是一致的.从而就可以将马克威茨的均值-方差准则中的正态假设减弱为位置-尺度分布族.这不仅扩大了均值-方差准则的应用范围,而且巩固了组合投资理论与资本资产定价理论的基础.     

Regulation of the intermittent release of giant unilamellar vesicles under osmotic pressure

Osmotic pressure can break the fluid balance between intracellular and extracellular solutions. In hypo-osmotic solution, water molecules, which transfer into the cell and burst, are driven by the concentration difference of solute across the semi-permeable membrane. The complicated dynamic processes of intermittent bursts have been previously observed. However, the underlying physical mechanism has yet to be thoroughly explored and analyzed. Here, the intermittent release of inclusion in giant unilamellar vesicles was investigated quantitatively, applying the combination of experimental and theoretical methods in the hypo-osmotic medium. Experimentally, we adopted a highly sensitive electron multiplying charge-coupled device to acquire intermittent dynamic images. Notably, the component of the vesicle phospholipids affected the stretch velocity, and the prepared solution of vesicles adjusted the release time. Theoretically, we chose equations and numerical simulations to quantify the dynamic process in phases and explored the influences of physical parameters such as bilayer permeability and solution viscosity on the process. It was concluded that the time taken to achieve the balance of giant unilamellar vesicles was highly dependent on the molecular structure of the lipid. The pore lifetime was strongly related to the internal solution environment of giant unilamellar vesicles. The vesicles prepared in viscous solution were able to visualize long-lived pores. Furthermore, the line tension was measured quantitatively by the release velocity of inclusion, which was of the same order of magnitude as the theoretical simulation. In all, the experimental values well matched the theoretical values. Our investigation clarified the physical regulatory mechanism of intermittent pore formation and inclusion release, which provides an important reference for the development of novel technologies such as gene therapy based on transmembrane transport as well as controlled drug delivery based on liposomes.     

钒氮共掺杂多孔碳催化剂上苄胺氧化偶联合成亚胺

本工作以生物质壳聚糖作为牺牲模板,乙酰丙酮钒为金属钒源,ZnCl₂为造孔剂,采用高温热解结合酸洗的策略制备出一种钒氮共掺杂多孔碳（V-N-C）催化剂。表征结果表明,V-N-C催化剂的比表面积高达1 470 m²·g^-1,孔容为1.06 cm³·g^-1,质量分数为0.19%的钒物种可能以单原子VN_x形式高度分散在载体上。在苄胺氧化偶联合成亚胺的反应中,V-N-C表现出高催化性能,底物苄胺的转化率和产物亚胺的选择性均为99%,性能明显优于均相VO（acac）₂和多相V₂O₅催化剂。此外V-N-C催化剂连续重复使用9次也未出现任何活性衰减的问题,且对一系列含有不同官能团的底物也具有优良的普适性。机理研究表明,苄胺和氧气首先分别在催化剂VN_x和缺陷位点活化成苄基亚胺和H₂O₂中间体,然后苄基亚胺与苄胺缩合脱NH₃生成目标产物亚胺。     

Pt/γ-Al2O3催化剂活性位的表征及其噻吩加氢脱硫催化活性

A series of Pt/γ Al 2O 3 catalysts with different content of Pt were characterized by using low temperature FT IR spectroscopy of adsorbed CO, while their catalytic activity for HDS was investigated with thiophene as a model substrate. On the basis of the experimental results, it has been obtained that the pseudo zero order rate of the thiophene HDS reaction is well linearly proportional to the total area of the two IR bands at 2?080 and 1?850 cm -1 of CO adsorbed on Pt/γ Al 2O 3, and that the Pt sites for CO adsorption may be the active centers for thiophene HDS reaction.     

硫化态三组元NiMoP/γ-Al2O3催化剂的TPR表征及噻吩HDS活性的研究

A series of sulfided tertiary NiMoP/γ-Al2O3 catalysts with different contents of MoO3 were prepared by using molybdophosphoric acid of Keggin structure(H3PMo12O40) and nickel nitrate as origins of active phase components of molybdenum, phosphorus and nickel, and characterized by TPR technique, with their HDS activity being investigated with thiophene as a model substrate. For the sulfided Mo-0 catalyst containing no nickel as promoter, the only hydrogen sulfide evolution peak Ⅰ　is observed at 462 K and attributed to the hydrogenation of the so-called edge sulfur atoms chemisorbed on coordinatively unsaturated(cus) Mox+ sites on the MoS2 phase(MoS2 slab). With the introduction of nickel into the active phase of the sulfided Mo-0 catalyst and with the increase of the molybdenum loading, a new hydrogen sulfide evolution peak Ⅱ gradually develops at the low temperature side of the peak Ⅰ, at the same time accompanied by both the increase of the area ratio of the peak Ⅱ to the peak Ⅰ and the shift of the hydrogen sulfide evolution maximum rate to lower temperatures, which may imply the existence of two kinds of active centers related to molybdenum and nickel respectively and the synergic action between the two centers above. It should be noted that for the sulfided NiMoP/γ-Al2O3 catalysts, the thiophene HDS rate and the quantity of hydrogen sulfide evolved during TPR process increase monotonously with the atomic ratio of molybdenum to nickel in the form of ［n(Ni)+n(Mo)］/n(Ni). On the basis of the results here, the conclusion may be reached that the two kinds of vacancies can be formed on the edge of Ni-Mo-S slab due to the loss of S during TPR process and vacancies or sites related to the H2S evolution peak II should be regarded as the mainly active reaction centers of thiophene HDS.