镁盐浸出离子吸附型稀土矿的环境影响评价及展望

离子吸附型稀土矿富含中重稀土元素,是世界罕见的稀土战略资源。针对工业普遍采用的硫酸铵浸出离子吸附型稀土矿引发的氨氮污染问题,前期研究工作提出采用镁盐代替硫酸铵作为新型浸取剂。本文就镁在土壤中的形态、作用及其有效性指标进行了综合论述,对镁盐浸出离子吸附型稀土矿的环境影响进行了分析,并提出了镁盐绿色浸取的发展方向。     

Co-culture Based Blood-brain Barrier In Vitro Model,a Tissue Engineering Approach using Immortalized Cell Lines for Drug Transport Study

This study evaluated the feasibility of using commercially available immortalized cell lines in building an in vitro blood-brain barrier (BBB) co-culture model for preliminary drug development studies. Astrocytes-derived acellular extracellular matrix (aECM) was introduced in the co-culture model to provide a novel biomimetic basement membrane for the endothelial cells to form tight junctions. Trans-Endothelial Electrical Resistance (TEER) and solute mass transport studies quantitatively evaluated the tight junction formation. Immuno-fluorescence microscopy and Western blot analysis qualitatively verified the expression of occludin, one of the tight junction proteins on the samples. Experimental data from a total of 13 experiments conclusively showed that the novel BBB in vitro co-culture model with aECM (CO + aECM) is promising in terms of establishing tight junction formation represented by TEER values, transport profiles, and tight junction protein expression when compared with traditional co-culture (CO) model setup or the endothelial cells cultured alone (EC). In vitro colorimetric sulforhodamine B (SRB) assay also revealed that the “CO + aECM” samples resulted in less cell loss on the basal sides of the insert membranes than traditional co-culture models. Our novel approach using immortalized cell lines with the addition of aECM was proven to be a feasible and repeatable alternative to the traditional BBB in vitro modeling.     

On heat transfer and flow characteristics of jets impinging onto a concave surface with varying jet arrangements

A new electrospinning process was developed for preparing TiO₂ nanofibers using a water-soluble Ti-precursor, [bis(kappa1O-hydroxo)(bis(kappa2O,O′-lactato)titanium(IV)] commonly known as titanium(IV) bis (ammonium lactato) dihydroxide (TiBALDH). The importance of the study is justified by the fact that Ti-precursors used for electrospinning, sol–gel, hydrothermal and other fiber synthesis processes are mostly non-water soluble. Accordingly, anatase TiO₂ nanofibers of diameter between 20 and 140 nm were synthesized by electrospinning and annealing. Polyvinylpyrrolidone (PVP) and different concentrations of TiBALDH were dissolved in a mixture of water, ethyl alcohol and acetic acid to optimize the electrospinning conditions. The thermal decomposition and fragmentation of PVP, TiBALDH and the fibers with 50% mass fraction of TiBALDH were studied by TGA-MS measurements. The fibers were then annealed at 1 °C min^?1 until 600 °C. The TiO₂ fibers were characterized using SEM–EDX, FTIR and XRD

     

Imaging through flesh tissue using fs electronic holographic gating method

The experimental results of imaging through flesh tissue using fs electronic holographic gating method is reported. In the experiment, Ti: sapphire mode-locked laser is used as light source, of which the repetition rate is 100 MHz, central wavelength 800 nm, duration of pulse 20 fs, output power 80 mW. Tissue is a 7 mm thick chicken slice, and the imaged object is a metal wire with diameter of 0.5 mm. A general CCD is used to record holograms and a clear image of metal wire is obtained. Several relevant problems are discussed.     

电商生态系统四方演化博弈研究

受启发于近些年频繁曝出的消费者权益保护问题,为探析消费者行为对电商生态系统中其他群体策略选择的影响,本文基于演化博弈理论,考虑消费者的投诉行为,构建由政府、电商平台、商家以及消费者组成的四方演化博弈模型;讨论各方主体的策略选择,分析策略组合稳定点,并应用MATLAB工具进行仿真模拟实验。经上述研究,本文得出结论：消费者的投诉行为有利于促进政府严格监管、电商平台严格管理、商家诚信经营。由此,建议政府和电商平台充分发挥监督管理作用,以更好地保障消费者的合法权益,并遏制消费者的恶意投诉行为,从而实现电商生态系统的稳定可持续发展。     

磷酸体系中微量稀土元素萃取动力学研究

采用新型恒界面池法进行了磷酸体系中用P204萃取La(Ⅲ),Sm(Ⅲ)和Y(Ⅲ)的动力学研究,考察了搅拌速度、温度、比界面积、磷酸浓度及萃取剂浓度等因素对萃取速率的影响.结果表明:磷酸体系中用P204萃取La(Ⅲ),Sm(Ⅲ)和Y(Ⅲ)的表观活化能E_a分别为27.0,22.2和21.1 kJ·mol~(-1),在体相P204浓度大于在液一液界面饱和吸附时的最低浓度C_(min)时,其在界面已达到吸附饱和,反应的主通道由界面变为体相,在该体系下P204萃取La(Ⅲ),Sm(Ⅲ)和Y(Ⅲ)反应为体相化学反应和扩散反应混合控制.     

在电光光学双稳中一种降低晶体半波电压的方法

本文采用非线性晶体调制函数曲线平移的计算方法和计算方程，并在实验上作了检证，绘制出电光晶体半波电压工作曲线、测试不同条件下的各种调制函数曲线和滞后回线。结果证明：电光晶体调制函数曲线平移法是一种有效制做非线性晶体半波电压Ｖｎ的光学方法。     

Dual‐Functional Small Molecules for Generating an Efficient Cytochrome P450BM3 Peroxygenase

We report a unique strategy for the development of a H₂O₂‐dependent cytochrome P450BM3 system, which catalyzes the monooxygenation of non‐native substrates with the assistance of dual‐functional small molecules (DFSMs), such as N‐(ω‐imidazolyl fatty acyl)‐l ‐amino acids. The acyl amino acid group of DFSM is responsible for bounding to enzyme as an anchoring group, while the imidazolyl group plays the role of general acid–base catalyst in the activation of H₂O₂. This system affords the best peroxygenase activity for the epoxidation of styrene, sulfoxidation of thioanisole, and hydroxylation of ethylbenzene among those P450–H₂O₂ system previously reported. This work provides the first example of the activation of the normally H₂O₂‐inert P450s through the introduction of an exogenous small molecule. This approach improves the potential use of P450s in organic synthesis as it avoids the expensive consumption of the reduced nicotinamide cofactor NAD(P)H and its dependent electron transport system. This introduces a promising approach for exploiting enzyme activity and function based on direct chemical intervention in the catalytic process.     

催化动力学光度法测定痕量钯

在磷酸－磷酸二氢钾缓冲溶液中，以钯（Ⅱ）催化次磷酸钠还原罗丹明Ｂ褪色为指示反应，建立了痕量钯的动力学光度分析新方法。在金（Ⅱ）的存在下，检测下限达５×１０＾－１１ｇ／ｍＬ钯（Ⅲ），方法应用于模拟合金样和含钯分子筛中钯的测定。结果满意。     

药物中亚硝酸根的流动注射催化光度法分析

以亚硝酸根催化溴酸钾在磷酸介质中氧化维多利亚天蓝Ｂ褪色为指示反应，建立了反相流动注射催化光度法测定痕量亚硝酸根的新方法。本法操作简单、快速，灵敏度高，测定亚酸根的线性范围为２￣８０μｇ／Ｌ，直接用于含硝酸内服药和针剂中亚硝酸根的测定，与α－萘胺比色法对照结果一致。