14 research outputs found
Investigations of metallic microcontamination on P-type silicon wafer surface
当今制造亚微米/纳米器件要求硅片表面必须达到原子水平上的洁净光滑,而硅表面的金属微观污染是造成电子元器件性能失效的重要原因之一。氢氟酸是硅片表面准备过程中最常用的化学试剂,溶液中含有的微量金属离子会对硅片表面产生污染。为了揭示其污染本质,从而控制或消除污染,本论文工作通过采用电化学测试技术(包括直流极化和交流阻抗技术)以及扫描电子显微镜(SEM)、能量散射X射线能谱(EDX)、X光电子能谱(XPS)、俄歇电子能谱(AES)等现代表面分析技术对稀释氢氟酸溶液中含有不同微量(10-6~10-9水平)金属(铜、铁、镍、钙)杂质时p型硅片表面的污染行为进行了较系统的研究。另外,我们还利用拉曼(Rama...Today the manufacturing of submicro-or-nano-meter devices are required clean and smooth at an atomic level for silicon surface. One of the important causes of failure in performance of electronic is attribute to metallic micro-contamination on silicon surface. HF is a chemical reagent most commonly used in surface preparation of wafers. Minor metal ions contained in HF solutions contaminate the si...学位:理学硕士院系专业:化学化工学院化学系_物理化学(含化学物理)学号:20022509
半导体硅片金属微观污染机理研究进展
综述了近10年来国内外在半导体硅片金属微观污染研究领域的进展。研究了单金属特别是铜的沉积、形成机理和动力学以及采用的研究方法和分析测试手段,包括对电化学参数和物理参数等研究。指出了随着科学技术的不断发展,金属污染金属检测手段也得到了丰富,为金属微观污染的研究提供了有力的工具
微量铜-铁对硅片表面污染的初步分析
通过比较微量铜铁单独存在和共存时对p -型硅片表面的污染,采用电化学直流极化和交流阻抗技术以及SEM、EDX和AES等现代表面分析技术,对未污染和受污染的硅片表面进行了初步的研究.结果表明,当氢氟酸溶液中同时含有ppb 水平(10-9)的铜铁杂质时,不但铜会沉积在硅片表面上发生铜污染,而且还导致硅片表面的碳污染,并从电化学极化电阻、元素深度分布和空间电荷效应等方面对硅片表面铜与碳污染进行了初步的分析和讨论
Universal primer PCR with SSCP and RFLP for identification of fish disease pathogens
采用通用引物PCR(UPPCR)、PCR RFLP、PCR SSCP技术 ,研究快速鉴别鱼病病原菌的分子生物学诊断技术。结果发现 ,采用细菌 16SrRNA基因保守区特异性引物 ,以嗜水气单胞菌、鲁克氏耶尔森菌、鳗弧菌、柱状曲挠杆菌、乙型链球菌、荧光假单胞菌等部分常见鱼病病原菌为对象 ,可以建立一种UPPCR技术。该技术能在保证实验条件不变的基础上 ,检出上述所有细菌 ,并还可检出大肠杆菌和双歧杆菌等非鱼病病原菌。并且认为 ,该法与SSCP配合即采用UPPCR SSCP技术能较好地鉴别被检菌而用于鱼病病原菌的快速诊断。A universal primer PCR(UPPCR), PCR RFLP and PCR SSCP had been screened for a molecular biological method that permitted the rapid identification of fish pathogens among them. The results showed that a universal primer PCR technology was available with specific primers from conserved regions of bacterial 16S ribosomal RNA genes. The bacteria tested included some common causative agents of fish diseases such as Aeromonas hydrophila, Yersinia ruckeri, Vibrio anguillarum, Flexibacter columnaris, beta Streptococcus, Pseudomonas fluorescens. The approach allowed the bacteria above and Escherichia coli and Bifidobacterium catenulatum detectable without any alterations of the experiment conditions. However, this study also found that the identification of species of bacteria tested depended on the combination of UPPCR and SSCP(PPCR SSCP), which was better than that of UPPCR and RFLP(UPPCR RFLP) and made rapid diagnosis of fish disease pathogens possible.国家自然科学基金!资助项目 (39770 5 85 );; IFS基金!(ImmunecomplexesinfreshfishinfectedFlexibactercolumnaris)资助项
Apoptosis induced by a novel intestinal metabolite of ginseng saponin in human hepatocellular carcinoma BEL-7402 cells
目的探讨一种新的人参稀有皂苷20-O-(β-D-吡喃葡萄糖)-20(S)-原人参二醇皂苷(IH-901)对人肝癌BEL-7402细胞的增殖抑制效果和诱导凋亡作用。方法以0、6.25、12.5、25、50、75、100μmol/L的IH-901作用于体外培养的BEL-7402细胞,通过MTT法检测IH-901对细胞生长的抑制作用,相差显微镜观察细胞形态变化,AO/EB的荧光核染色观察凋亡细胞形态,流式细胞术检测细胞周期和细胞凋亡。结果MTT实验显示IH-901抑制BEL-7402细胞的生长,呈时间及浓度依赖的方式;显微镜下观察到典型的凋亡形态变化和生化特征:细胞固缩,核染色质凝聚,出现凋亡小体;AO/EB的荧光核染色后,观察到典型的凋亡细胞;流式细胞仪可以检测到凋亡峰,且细胞被阻滞在G0/G1期。结论IH-901能通过诱导细胞凋亡的方式有效地抑制人肝癌BEL-7402细胞的生长,稀有人参皂苷IH-901可能成为一种潜在的抗肝癌药物。Objective To investigate the effects of 20-O-(β-D-glucopyranosyl)-20(S)-protopanaxadiol(IH-901) on the human hepatocellular carcinma BEL-7402 cells in terms of inhibition of proliferation and induction of apoptosis.Methods BEL-7402 Cells in cultural medium in vitro were given 0,6.25,12.5,25,50,75,and 100 μmol/L IH-901.The inhibitory rate of cells was measured by MTT assay,morphology of cell apoptosis was observed by AO/EB fluorescent staining,cell apoptotic rate and cell phase were detected by flow Cytometry(FCM).Results The results indicated that IH-901 could inhibit the proliferation of BEL-7402 cells significantly.The suppression was both in a time-and dose-dependent manner.Morphological examination of IH-901-treated samples showed cells with chromatin condensation,cell shrinkage,and all typical characteristics of apoptotic cells.Marked morphological changes of cell apoptosis was observed very clearly by AO/EB fluorescent staining.The increase in the apoptotic sub-G1 fraction in a concentration-dependent manner and cell cycle arrest at the G0/G1 phase were detected by FCM.Conclusion The results demonstrate that IH-901 dramatically suppresses BEL-7402 cell growth by inducing programed cell death.These results may provide a pivotal mechanism for the use of IH-901 in the prevention and treatment of human hepatocellular carcinoma BEL-7402 cells,the antiproliferation,and the apoptosis厦门市科技创新基金重点项目(3502Z20062008
福建绞股蓝皂苷的优化提取及其抗肝癌活性
绞股蓝素有"南方人参"美誉,含有与人参皂苷相同骨架达玛烷型结构的三萜皂苷。通过不同体积分数乙醇溶液优化提取绞股蓝皂苷,测定其抗癌活性,为后续活性化合物的分离奠定基础。利用HPLC分析绞股蓝的皂苷成分并确定提取绞股蓝皂苷的乙醇体积分数,正交实验优化提取方法,进而MTT法测定提取的绞股蓝皂苷抗肝癌活性。HPLC分析确定用体积分数75%乙醇溶液提取绞股蓝总皂苷(GYP),体积分数45%乙醇提取极性绞股蓝皂苷(GYP1),体积分数90%乙醇提取弱极性绞股蓝皂苷(GYP2);正交实验结果表明在70℃水浴中以30质量的体积分数45%乙醇加热提取12 h为最佳条件提取GYP1,在60℃水浴中以30质量的体积分数90%乙醇加热提取6 h为最佳条件提取GYP2;利用MTT法测定GYP、GYP1和GYP2对肝癌细胞的抑制作用,GYP和GYP2对肝癌细胞SMCC7721具有抗癌活性,半抑制率IC50值分别为(165.83±14.12)μg/mL和(113.97±9.26)μg/mL,GYP1没有抗癌活性,表明绞股蓝抗癌药效成分主要是由弱极性绞股蓝皂苷发挥功效
On Rationality and Feasibility of "Real-name Recommendation System of Secondary School Headmasters"
“中学校长实名推荐制“是国内高校实施自主招生政策下的一种有争议的改革尝试。本文从“推荐制“本身的合理性和可行性出发,揭示其与现有高校招生考试制度的匹配性,并结合分析香港、美国、日本的“推荐制“情况,取长补短、理性权衡,对国内招生录取制度改革进行有益探索,以深化教育体制改革。"Real-name recommendation system of secondary school headmasters" is a controversial reform under the autonomous admissons policy implemented in colleges and universities.This article,from the rationality and feasibility of recommendation system,reveals the matching of the recommendation system and college entrance examination system and analyzes the recommendation system in Hong Kong,the United States and Japan and learns from their strong points to explore our college entrance examination system reform for the deepening reform of educational system.福建省教育厅社会科学研究项目“教育考试与评价的公平性研究”(项目批准号JA08289S)研究成果之
珠江的鱼类区系及其动物地理区划的讨论
本文根据珠江水系实地调查的结果,对珠江淡水鱼类区系的组成、形成原因及其在动物地理区划中的位置进行了讨论,否定了前人将南岭山脉作为东洋区和古北区在东亚的分界线的观点,认为这两个大区的界线应向北推移到秦岭山脉,并且指出珠江水系的鱼类区系元大部分隶属于东洋区的南东亚亚区,而其西江上源的一小部分应划归南亚亚区
相似理论与模化
随着科学技术的迅速发展,近代工程设计所面临的任务更加复杂,解决问题的手段也更加先进。量纲分析是解决工程技术问题的重要手段之一,这是因为:(1)借助于量纲分析,当存在着多种影响因素的情况下,往往能够分辨出哪些因素是重要的,因而其他因素在设计中可以不加考虑。(2)量纲分析是建立相似律的基本方法,而相似律既是设计模型试验的理论依据,又是整理试验数据,推广试验结果应用范围所必须遵循的原则。本篇从量纲分析出发,给出一般的相似原理和模化原则,以及它们在若干常见问题中的应用