纳米电子器件呼唤真空化学研究

纳米电子器件是微电子器件发展的下一代 ,现有微电子器件的主要材料是极纯的硅、锗和镓砷等晶体半导体。纳米电子器件有可能是以有机或有机 /无机复合晶体薄膜为主要材料 ,要求纯度更高 ,结构更完善。真空制备的清洁环境 ,有希望加工组装出纳米电子器件所要求的结构。故本文建议开展真空化学研究     

表面胶转化法合成亚微米厚度MFI型分子筛薄膜应用于快速择形分离己烷异构体

在膜分离中,薄膜超薄化对促进气体传输至关重要,而将膜厚降至亚微米级则极具挑战性.本文中,我们提出表面胶转化法来合成亚微米厚度的纯硅MFI分子筛膜.通过精细调控前驱体化学组成制备了低浸润性的黏性胶,有效防止凝胶从氧化铝载体表面渗透至空隙中.在晶种的诱导下,辅以少量水蒸气,表面凝胶经历了直接和完全晶化过程,形成了厚度为~5...     

用FoxPro设计与实现有机化学试题库系统

要使有机化学考试出卷更为规范、科学,有一个好办法就是使用试题库系统,用计算机来命题组卷。本文首先介绍了有机化学试题在数据库中的存储方法,然后介绍了如何用FoxPro软件来设计并实现有机化学试题库系统。     

叶城县县城供水扩建工程地下取水论证与影响分析

介绍了叶城县县城供水扩建工程取水方案,以水源地所在的水文地质单元为分析范围,通过调查区内的地形、地貌特征,地层岩性及含水层空间分布与贮存条件,分析研究地下水的补给、径流、排泄条件,采用现场抽水试验计算探讨了地表水入渗给量和廊道出水量,用开采系数法和水平集水建筑物涌水量计算法计算可开采量,并对水质和取水影响进行了分析,阐...     

Copper‐Free Clickable Coatings

The copper‐catalyzed azide–alkyne 1,3‐dipolar cycloaddition (CuAAC) is extensively used for the functionalization of well‐defined polymeric materials. However, the necessity for copper, which is inherently toxic, limits the potential applications of these materials in the area of biology and biomedicine. Therefore, the first entirely copper‐free procedure for the synthesis of clickable coatings for the immobilization of functional molecules is reported. In the first step, azide‐functional coatings are prepared by thermal crosslinking of side‐chain azide‐functional polymers and dialkyne linkers. In a second step, three copper‐free click reactions (i.e., the Staudinger ligation, the dibenzocyclooctyne‐based strain‐promoted azide–alkyne [3+2] cycloaddition, and the methyl‐oxanorbornadiene‐based tandem cycloaddition?retro‐Diels?Alder (crDA) reaction) are used to functionalize the azide‐containing surfaces with fluorescent probes, allowing qualitative comparison with the traditional CuAAC.     

Characterization of the Secretome of a Specific Cell Expressing Mutant Methionyl-tRNA Synthetase in Co-Culture Using Click Chemistry

Co-culture system, in which two or more distinct cell types are cultured together, is advantageous in that it can mimic the environment of the in vivo niche of the cells. In this study, we presented a strategy to analyze the secretome of a specific cell type under the co-culture condition in serum-supplemented media. For the cell-specific secretome analysis, we expressed the mouse mutant methionyl-tRNA synthetase for the incorporation of the non-canonical amino acid, azidonorleucine into the newly synthesized proteins in cells of which the secretome is targeted. The azidonorleucine-tagged secretome could be enriched, based on click chemistry, and distinguished from any other contaminating proteins, either from the cell culture media or the other cells co-cultured with the cells of interest. In order to have more reliable true-positive identifications of cell-specific secretory bodies, we established criteria to exclude any identified human peptide matched to bovine proteins. As a result, we identified a maximum of 719 secreted proteins in the secretome analysis under this co-culture condition. Last, we applied this platform to profile the secretome of mesenchymal stem cells and predicted its therapeutic potential on osteoarthritis based on secretome analysis.     

TEMPORAL AND SPATIAL DISCRETIZATION ON QUASI-3-D GROUNDWATER FINITE ELEMENT MODELLING TO AVOID SPURIOUS OSCILLATION

In this article, the finite element solution of quasi-three-dimensional (quasi-3-D) groundwater flow was mathematically analyzed. The research shows that the spurious oscillation solution to the Finite Element Model (FEM) is the results choosing the small time step ?t or the large element size L and using the non-diagonal storage matrix. The mechanism for this phenomenon is explained by the negative weighting factor of implicit part in the discretized equations. To avoid spurious oscillation solution, the criteria on the selection of ?t and L for quasi-3-D groundwater flow simulations were identified. An application example of quasi-3-D groundwater flow simulation was presented to verify the criteria. The results indicate that temporal discretization scale has significant impact on the spurious oscillations in the finite-element solutions, and the spurious oscillations can be avoided in solving practical quasi-3-D groundwater flow problems if the criteria are satisfied.     

Influence of Seepage Face Obliquity on Discharge of Groundwater and its Pollutant into Lake from A Typical Unconfined Aquifer

Lab experiment and mathematical simulation Modular three dimensional finite difference groundwater (MODFLOW) were performed in a soil tank to simulate the hydrogeochemical interaction between lake and typical unconfined aquifer. Results show that the velocity decreases exponentially with the transect distance on seepage face. The maximal velocity occurs at the top point of seepage face. The obliquity of seepage face has a great influence on the maximum and distribution of seepage velocity. With the increase of the obliquity of seepage face, the maximal velocity decreases quickly and the velocity distribution becomes much more even. Most of groundwater flow and pollutant flux discharges through a narrow portion near the top of seepage face. The flow and mass concentrated in the narrow portion increase with the decrease of the obliquity of seepage face. These will benefit to design a reasonable and economical scenario to manage lakeshore and to control the pollution of lake water near lakeshore.     

一种新型结构碳材料——碳管套碳纳米丝

以氢气和甲烷为气源,利用钟罩式微波等离子体化学气相沉积(MW PCVD)系统制备了一种新型结构碳材料——碳管套碳纳米丝,用扫描电子显微镜和拉曼光谱仪对它的形态结构和成份进行了分析。这种新型结构碳材料,具有与碳纳米管、碳纳米丝相似的性质,并在某些领域(如电子源探针、纳米电子器件等)具有很好的应用前景。