银纳米颗粒溶胶表面增强红外基底对低浓度福美双农药的快速检测

采用水热法制备了一种银纳米颗粒溶胶,通过乙醇洗涤后得到银纳米颗粒表面增强红外基底,用于检测低浓度福美双农药。结果表明,该增强基底可检测低至10^-7mol/L的福美双农药,且不同浓度下福美双溶液的表面增强红外光谱强度呈现良好的线性关系,该基底对福美双分子的红外光谱增强能力高达150倍。银纳米颗粒的富集作用、电荷转移机制和电磁增强机制的共同作用使福美双的红外光谱得到显著增强。     

胞嘧啶分子在不同基底上的拉曼散射研究

用几种不同的方法制备了银纳米颗粒和银纳米点阵,分别通过透射电子显微镜和扫描电子显微镜表征了纳米颗粒的形貌,并研究了胞嘧啶分子吸附在这几种银纳米颗粒上的表面增强拉曼散射光谱,结果分析表明:(1)银纳米颗粒粒径在50nm左右时产生的增强效果最强;(2)胞嘧啶通过羧基和N3位垂直吸附于纳米银颗粒表面.     

SiO_2包覆的银纳米颗粒及其团簇的表面增强荧光效应

在高温条件下以乙二醇为还原剂,制备银纳米颗粒,并用改良的St?ber方法,在银纳米颗粒及其多聚体外面包覆一层8 nm左右的二氧化硅,制备出Ag@SiO_2复合纳米颗粒.二氧化硅壳层的包覆不仅可以调控有机分子和银纳米颗粒之间的距离,避免荧光猝灭,还可以提高金属颗粒的分散性和稳定性,有效地拓展其在生物领域中的应用.利用电子束刻蚀技术在衬底表面做记号,成功标记出单个状态的Ag@SiO_2复合纳米颗粒及其多聚体.以Rh6G为探测分子,系统研究了颗粒尺寸、多聚体聚合程度以及激发光的偏振性质对表面增强荧光效应的影响.结果表明,Ag@SiO_2纳米复合衬底对吸附在其表面的Rh6G分子具有明显的荧光增强作用,且增强效果受到颗粒粒径、团聚程度、分布方式以及偏振性质变化的调控.     

纳米银溶胶中超痕量分子的Raman光谱

根据柠檬酸钠还原硝酸盐的原理制备直径为80~90 nm的银纳米颗粒溶胶, 采用1 mW激光功率和5 s积分时间, 通过表面增强Raman散射技术检测到浓
度为10^-13 mol/L水中的超痕量若丹明6G分子, 通过制备银纳米膜的方法检测到浓度为10^-11 mol/L的超痕量R6G分子. 实验结果表明, 若银纳米颗粒的密度降低, 则其增强Raman散射的能力减弱.     

一种适于水相中使用的表面增强拉曼散射基底的制备

利用自组装技术和银镜反应给出了一种制备表面增强拉曼散射基底的新方法.以自组装的方法在玻璃基片上组装巯丙基三甲氧基硅烷分子膜,利用这层分子膜使银纳米颗粒与基底表面形成较强的化学键结合.通过优化银镜反应条件,得到了可以长时间在水相中使用的高活性表面增强拉曼散射基底.结果显示其检测灵敏度可达单分子层,且具有很好的稳定性和重复性.     

化学镀法制备图案化银纳米颗粒单层膜

一步法完成Ag纳米颗粒的制备及图案化组装,开辟低成本、高效率制备图案化银纳米颗粒单层膜的新途径。采用微接触印刷技术,将有机分子十六烷基硫醇(HDT),1,10-癸二硫醇硫醇(DDT)选择性自组装在金表面,通过化学镀法在基底材料上制备高度分散有序直径约为10nm的球形银纳米颗粒。得到规则有序的图案化银纳米颗粒单层膜。采用自主装诱导技术结合化学镀法,制备Ag纳米颗粒的同时,完成图案化银纳米颗粒薄膜的制备。图案化分散有序的金属纳米颗粒在表面催化和微电子器件制备方面有广阔的应用前景。     

Ag@Au双金属纳米颗粒的制备和表征

采用种子生长法制备了银纳米颗粒,通过电置换反应将单金属银颗粒转变为中空金银双金属纳米颗粒.电镜表征及吸收光谱的结果表明,通过控制种子溶液的加入量、超声时间和离心次数等条件,能够有效调控金属纳米颗粒的尺寸以及局域表面等离激元的共振峰位与目标分子匹配;进而可以利用配体交换反应在金属纳米颗粒表面包裹TDBC分子薄膜,实现表面等离激元-分子激子的强耦合.     

局域表面等离子体增强锗的光电响应特性

局域表面等离子体共振(local surface plasmon resonance,LSPR)因其对光独特的响应特性而在纳米光电子领域成为研究的重点.作为重要的微电子材料,锗在近红外波段的光电响应较弱,而把局域表面等离子体应用在锗材料中,必然会改善锗的光电响应特性.利用时域有限差分(finite difference time domain,FDTD)法,详细研究了1,2,3个银纳米颗粒嵌入锗中的消光光谱.结果发现,在可见光以及近红外比较宽的波长范围内,这种复合结构可以有效增强锗的光电响应特性,且多个孤立的银纳米颗粒会表现出与1个银纳米颗粒不一样的光电响应特性.同时,LSPR导致的光响应特性与光源的偏振、颗粒尺寸、颗粒个数以及颗粒之间的距离有依赖关系.这一结果不仅对锗在光电子领域的应用有重要意义,也可以拓宽局域表面等离子体在纳米光电子领域的应用范围.     

表面增强拉曼光谱研究尼古丁与金属纳米粒子的相互作用

以金、银纳米及Au@Ag、Au-Ag合金复合纳米粒子为基底,研究尼古丁分子的表面增强拉曼光谱,讨论分子在4种纳米粒子表面的作用方式及可能的吸附取向.结果表明,分子在金纳米和Au-Ag合金纳米粒子表面的吸附取向相同——垂直吸附,不同的是与金纳米粒子形成了稳定的N-Au键;由于银纳米粒子和Au@Ag核壳纳米粒子表面均富含大...     

利用SERS技术和DFT计算方法对糠醛分子的振动光谱研究

从实验上测量了糠醛分子(Fu)的正常拉曼谱(NRS),同时又运用了密度泛函理论(DFT)计算了糠醛分子的振动光谱,计算时采用了B3LYP混合泛函和6-31G基函数组,理论计算结果很好地符合了实验测量结果。还报告了糠醛分子在固态银纳米颗粒表面的表面增强拉曼散射(SERS)光谱,最后对糠醛分子在银纳米粒子表面上的可能吸附状态进行了讨论。     

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.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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-