注银热解碳的抗菌机理研究

使用革兰氏阳性菌--金黄色葡萄球菌,对注银热解碳的抗菌机理作了探讨分析.银离子的注入能量为70 keV,注入剂量分别为 5×1014, 1×1016, 5×1017 ion/cm2.用俄歇电子能谱(AES)和X射线光电子能谱(XPS)对样品表面进行了微观分析.结果表明:材料表面形成了富银层;对注银剂量相同的热解碳,直接接触的抗菌效果比其滤液的抗菌效果好.说明注银热解碳的抗菌作用是溶出的银离子和未溶出的材料表面络合状银离子的共同抗菌结果,且杀菌以银离子溶出为主.     

不锈钢及以其为基底的TiN膜注银的抗菌性的XRD分析

择优取向为(111)的TiN涂层，沉积表面光滑、硬度高、耐磨性好、结合强度高、耐腐性能强，因此，被用于矫形外科及骨植入材料．银离子有很好的抗菌性，所以生长含银的TiN膜可将这些优良的机械和生物性能相结合．本文研究银离子注入不锈钢及以不锈钢为基底的TiN膜的微观结构对其抗菌机理的影响．XRD分析的结果表明Ag 注入没有影响TiN(111)择尤取向．银在不锈钢和TiN膜上的晶面择优取向为(200)，(111)．这有可能是银注入这两种材料不同抗菌性的原因．     

银离子注入TiN薄膜的抗菌性和抗腐蚀性研究

为了制备具有抗菌性和抗腐蚀性的医用不锈钢,通过离子注入方法,在镀有TiN薄膜的医用不锈钢317L上注入银离子,用振荡平板法测试了其对革兰氏阴性大肠杆菌(E.coil)和革兰氏阳性金黄色葡萄球菌(S.aureus)的抗菌率;用电化学腐蚀方法检测了薄膜在Hank's模拟体液中的耐腐蚀性能;通过X射线光电子能谱(XPS)和俄歇电子能谱(AES)分析了薄膜的结构特征和各元素的深度分布.结果表明,当离子注入剂量接近饱和注入剂量时,样品的抗菌性能最强,但其抗腐蚀性相应下降.     

Ag~+注入对TiO_2薄膜光催化、抗菌和亲水性能的影响

为提高TiO2材料的光催化能力,采用匀胶法在载玻片上制备TiO2薄膜,通过离子注入技术在TiO2薄膜表面掺杂Ag+,离子注入时加速电压为40kV,注入剂量分别为5×1015、1×1016、3×1016、6×1016和1×1017ions/cm2.以甲基橙为降解物,研究了Ag+注入对TiO2薄膜紫外光作用下光催化效率的影响,并通过大肠杆菌在紫外光照射下的存活率考察了Ag/TiO2薄膜的抗菌效率.此外,利用接触角测量仪测量Ag/TiO2薄膜分别在避光和紫外光照射下水接触角的变化情况,研究了Ag+注入对TiO2薄膜亲水性的影响.实验结果表明:注入剂量为1×1016ions/cm2时,TiO2薄膜光催化效率最高,与未注入薄膜比较提高了约1.26倍.此外,适量的Ag+注入有利于TiO2薄膜抗菌效率的提高,并改善了薄膜的亲水性能,紫外光作用下,薄膜具有最佳抗菌性和亲水性时,Ag+的注入剂量为3×1016ions/cm2.     

沉积温度对直流磁控溅射TiN薄膜结构和表面形貌的影响

利用直流磁控溅射技术,在锆合金基体表面上研究不同基体温度对沉积TiN薄膜的影响.分别采用X射线衍射仪和扫描电子显微镜(SEM)对TiN薄膜结构、表面形貌和截面形貌进行了研究.研究结果表明:TiN薄膜在不同沉积温度下晶格取向是不同的;200℃时,TiN为随机取向;300℃时,TiN薄膜以(111)为择优取向;400℃时,薄膜晶化质量不断提高,最后逐渐趋于稳定.300℃时,薄膜的致密性与均匀性较好,表面无明显缺陷.     

注银碳基生物医学材料的抗菌机理研究

选用革兰氏阴性菌-大肠杆菌,采用平板菌落计数法对注银碳基生物医学材料样品直接接触和间接接触的抗菌效果进行对比.研究结果表明:注银后材料表面形成的富银层是材料抗菌性的主要原因.对注银剂量相同的样品,直接接触比其滤液的抗菌效果好,说明注银碳基材料的抗菌性是溶出的银离子和材料表面未溶出的络合状银离子共同作用的结果,且以银离子溶出杀菌为主.通过紫外光谱法探究银离子和细菌染色体DNA的相互作用机制,发现银离子与DNA之间存在静电和碱基作用,导致DNA分子天然构象遭到破坏,起到抗菌作用.     

玻璃上Ag/ZnO 薄膜的形成过程

扩展一种和玻璃基体结合力高的化学镀铜技术,它在玻璃表面上喷雾覆盖一层醋酸锌,然后热解形成半导体氧化锌薄膜．将此附有氧化锌的玻璃浸渍硝酸银稀溶液,利用光还原法将银离子还原为单质银,并以银为催化剂在附有氧化锌薄膜的玻璃上化学镀铜．文中通过差热-热重分析(TGDTA)、X-射线衍射(XRD)和扫描电境(SEM)表征了上述过程,探讨半导体氧化锌光还原银离子的机理．     

纳米TiO2玻璃膜的制备与表征

以钛酸丁酯和无水乙醇为原料,加硝酸银引入银离子,采用溶胶凝胶法和浸渍提拉法在玻璃表面施涂膜层,控制提拉速度6cm/min,经500℃热处理,制得均匀透明的多孔纳米TiO2玻璃.通过对样品XRD、SEM等分析的研究,二氧化钛薄膜主要呈锐钛矿相,而且其纳米颗粒大小在50-100nm范围.以大肠杆菌为菌种,对样品进行抗菌测试结果表明:银的抗菌机理为银离子接触抗菌,添加少量银离子,薄膜即有良好的抗菌能力.透光率分析表明纳米TiO2玻璃的透光性较好,在可见光范围内相对于普通玻璃的透光率在65%以上.     

直流磁控溅射法在Mg-Li合金表面沉积TiN薄膜提高合金抗腐性的研究

TiN薄膜具有良好的抗腐蚀性,采用直流磁控溅射法低温下合成TiN薄膜可以节约能源,简化工艺.采用直流磁控溅射法在Mg-Li合金表面沉积TiN膜,TiN膜厚度约为1.6μm,靶材为纯度99.99%的钛靶.用X射线衍射仪(XRD)来表征薄膜的成分,薄膜的表面形貌用扫描隧道显微镜(SEM)以及原子力电子显微镜(AFM)来表征.将样品放入浓度为3.5%的NaCl溶液中进行腐蚀实验,结果镀TiN膜的镁锂合金样品析氢速率很慢;用SEM进行腐蚀表面观察,未镀TiN薄膜的合金表面比镀TiN薄膜的合金表面腐蚀严重,说明在Mg-Li合金表面沉积TiN薄膜提高了镁锂合金的抗腐蚀性.     

基体温度对磁控溅射TiN薄膜结构与力学性能的影响

采用直流反应磁控溅射方法在304不锈钢表面沉积TiN薄膜.利用场发射扫描电镜、X射线衍射仪和纳米压痕仪研究基体温度对TiN薄膜结构与性能的影响.结果表明:TiN薄膜为柱状结构,表面平整、致密.薄膜为面心立方结构(fcc)TiN并存在择优取向,室温和150℃时薄膜为(111)晶面择优取向,300和450℃时薄膜为(200)晶面择优取向;室温时薄膜厚度仅为0.63μm,加温到150℃后膜厚增加到1μm左右,但继续加温对膜厚影响不明显;平均晶粒尺寸随着基体温度的升高略有上升;薄膜的硬度、弹性模量和韧性(H3/E*2)随基体温度的升高而增加,最值分别达到25.4,289.4和0.1744GPa.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that