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1.
以海鞘(Ciona savignyi)为研究对象,考察了海鞘血细胞原代培养方法及培养中细菌污染的鉴定和控制.血细胞在培养1 h后贴壁,细胞基本以圆形细胞为主,变形细胞一般呈不规则形.变形细胞存活时间较短,而圆形细胞存活时间较长.对于培养过程中的细菌污染,通过细菌分离、培养和纯培养发现两类菌株检出率较高,均为革兰氏阴性菌.经PCR扩增16S rDNA基因序列片断,结果显示这两类菌株分别属于弧菌属(Vibrio)和施万氏菌属(Shewanella).药敏试验结果显示,弧菌属对氯霉素和环丙沙星等具有较强的敏感性;对施万氏菌属较敏感的药物依次为亚胺培南和氯霉素等.最后比较了几种抗生素组合控制血细胞培养中细菌污染的使用效果,其中氯霉素、亚胺培南加双抗的组合有较好的抑菌效果并对培养细胞的贴壁和生长没有影响.  相似文献   
2.
侧重于传统医学药用矿物特定品种资源的研究,完善了矿物药研究的内容,是应用矿物学的重要课题之一。着重分析了药用矿物研究方向和相应研究方法。地道药材传统产地的考证及其典型样品的对比研究是基础工作。传统品种资源现状的经济地质研究,稀缺品种的资源调查,著名中成药、矿物药制剂矿物原料的资源研究,药用矿物地方资源的开发利用,特定地区地方病防治药物的资源调查,均需借助典型样品产地地质地球化学背景资料和矿物学标志,即矿物组份、化学成分(主次元素及微量元素)、成因等资料;新开发品种的资源研究更需配合药理分析和跟踪临床效果而提出的资源筛选。  相似文献   
3.
For the purposes of a thesis at the Institute of avalanche and torrent control at the university of agriculture in Vienna a comparison of two avalanche-models, a hydraulic one from Voellmy/Salm/Gubler and a statistical one from Laatsch/Zenke/Dankerl with exemplary exactly known avalanches of Tyrol and Switzerland was started in 1993. The result of this work was that both models failed by the calculation of avalanches with high recurrence intervals (over 300 years). For the calculation of avalanches with recurrence intervals under 300 years the results of both models are regular. The conclusion is that a combination of two models i.e. a hydraulic one improved by statistical calculations will be the best.  相似文献   
4.
Changes in the UV spectra of As(OH)3 solutions with variations in pH and temperature have recently been used to determine the temperature dependence of the pKa of the acid. In previous studies I used quantum mechanical techniques to study changes in structure and vibrational spectra as a function of pH for arsenites and thioarsenites. I previously calculated UV spectra for ``molecular' minerals, like realgar As4S4. Here I use a number of different quantum mechanical methods, both Hartree-Fock and density functional theory based, to calculate the UV spectra for both a related simple well-characterized gas-phase molecule PF3 and for As(OH)3 and As(SH)3 and their conjugate anions and some neutral and anionic oligomers in aqueous solution. For the monomeric species small numbers of water molecules have been explicitly included, in a supermolecule or microsolvation approach. I find that UV absorption energies accurate to a few tenths of an eV can be obtained both for gas- phase PF3 and for neutral arsenious acid in aqueous solution, for which the UV absorption maximum is calculated to occur around 6.5 eV, consistent with experiment. Accurate calculation of the UV energies for arsenite anions in aqueous solution is much more difficult, since basis set size and solvation effects are considerably larger than for the neutral molecules, but fairly reliable results can still be obtained. Deprotonation is found to reduce the lowest calculated UV transition energy by about half an eV. Oligomerization also reduces the lowest calculated UV energy by at least half an eV. Replacement of one or all the –OH groups by –SH groups reduces the lowest calculated UV energies by about 2 eV. UV excitation energies have been calculated for oligomeric species as large as As3E3(EH)3 and As4E6, where E = O, S, and may be useful for identifying such species in solution.  相似文献   
5.
6.
We present here a numerical modelling study of dislocations in perovskite CaTiO3. The dislocation core structures and properties are calculated through the Peierls–Nabarro model using the generalized stacking fault (GSF) results as a starting model. The GSF are determined from first-principles calculations using the VASP code. The dislocation properties such as collinear, planar core spreading and Peierls stresses are determined for the following slip systems: [100](010), [100](001), [010](100), [010](001), [001](100), [001](010), and All dislocations exhibit lattice friction, but glide appears to be easier for [100](010) and [010](100). [001](010) and [001](100) exhibit collinear dissociation. Comparing Peierls stresses among tausonite (SrTiO3), perovskite (CaTiO3) and MgSiO3 perovskite demonstrates the strong influence of orthorhombic distortions on lattice friction. However, and despite some quantitative differences, CaTiO3 appears to be a satisfactory analogue material for MgSiO3 perovskite as far as dislocation glide is concerned.  相似文献   
7.
GPS地壳形变监测网应变解算方法与程序设计   总被引:5,自引:2,他引:5  
分析了在平面直角坐标系和大地坐标系内解算应变的方法及其特点,并以Matlab为开发平台,研制出一套在平面直角坐标系和大地坐标系中解算应变的程序GPSstrain。利用GPS监测网测站位移(速率),该程序能够解算剪切应变(γ1、γ2)、面应变、块体旋转、主应变及其方向、最大剪切应变及其方向,同时也可解算出这些应变分量的误差。另外该程序还具有高斯投影解算功能,根据各测站坐标能够自动形成所有的Delaunay三角形,并以图形方式显示。最后以实际算例给出了该解算程序的部分结果,并进行了初步的分析和讨论。  相似文献   
8.
贩卖毒品是实现毒品犯罪经济利益的重要环节,是危害最为严重的毒品犯罪类型之一。现有研究主要关注毒品犯罪与建成环境之间的关系,没有顾及打击后贩卖毒品犯罪空间转移现象以及影响因素的变化。本文基于日常活动理论、犯罪模式理论和社会解组理论,以中国ZG市主城区为例,融合多源时空数据,分别对2013年8月开始的“雷霆扫毒”前后的贩卖毒品犯罪构建负二项回归模型,分析微观尺度下半公共空间、室外公共空间和室内私人空间对贩卖毒品犯罪影响的变化。研究发现“雷霆扫毒”行动后:① 贩卖毒品犯罪案件数量显著下降;② 半公共空间对贩卖毒品犯罪的影响作用减弱;③ 室外公共空间对贩卖毒品犯罪影响作用增强,室内私人空间对贩卖毒品犯罪的影响上升。结果表明:“雷霆扫毒”专项行动开展后一年,贩卖毒品犯罪的“主阵地”发生变化,由城市半公共空间逐渐向室外公共空间和室内私人空间转移。特别的是,“雷霆扫毒”对大毒枭及贩毒团伙的打击成效突出,促使2014年贩毒案件大幅度下降,实现了专项行动开展的目的。后续一系列专项行动进一步提升了对贩卖毒品犯罪的发现和查处能力,显示出专项行动对打击隐性犯罪的明显效果。研究表明公安执法部门必须对毒品贩卖犯罪进行持续的、有针对性的打击,对发生地的变动进行定期的监控,不能一蹴而就。  相似文献   
9.
Phase equilibria simulations were performed on naturally quenchedbasaltic glasses to determine crystallization conditions priorto eruption of magmas at the Mid-Atlantic Ridge (MAR) east ofAscension Island (7–11°S). The results indicate thatmid-ocean ridge basalt (MORB) magmas beneath different segmentsof the MAR have crystallized over a wide range of pressures(100–900 MPa). However, each segment seems to have a specificcrystallization history. Nearly isobaric crystallization conditions(100–300 MPa) were obtained for the geochemically enrichedMORB magmas of the central segments, whereas normal (N)-MORBmagmas of the bounding segments are characterized by polybariccrystallization conditions (200–900 MPa). In addition,our results demonstrate close to anhydrous crystallization conditionsof N-MORBs, whereas geochemically enriched MORBs were successfullymodeled in the presence of 0·4–1 wt% H2O in theparental melts. These estimates are in agreement with direct(Fourier transform IR) measurements of H2O abundances in basalticglasses and melt inclusions for selected samples. Water contentsdetermined in the parental melts are in the range 0·04–0·09and 0·30–0·55 wt% H2O for depleted and enrichedMORBs, respectively. Our results are in general agreement (within±200 MPa) with previous approaches used to evaluate pressureestimates in MORB. However, the determination of pre-eruptiveconditions of MORBs, including temperature and water contentin addition to pressure, requires the improvement of magma crystallizationmodels to simulate liquid lines of descent in the presence ofsmall amounts of water. KEY WORDS: MORB; Mid-Atlantic Ridge; depth of crystallization; water abundances; phase equilibria calculations; cotectic crystallization; pressure estimates; polybaric fractionation  相似文献   
10.
Knowledge of the defect properties of Lunar and Mercurian minerals has recently become important, with the advent of models which attempt to explain the formation of the thin exosphere of these celestial bodies. Here, we have calculated the formation energies of sodium and oxygen vacancies in the mineral albite (NaAlSi3O8), as well as the Schottky defect energy for the removal of a Na2O unit. We have employed both the supercell and Mott–Littleton approaches, using Kohn–Sham density functional theory and classical interatomic potential methods. As well as reporting the defect energies and structures, we comment upon the relative merits of the methods used.  相似文献   
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