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基于铜离子修饰金纳米簇“关-开”型荧光探针检测多巴胺  [PDF]
于锡娟,韩璐璐,混旭
- , 2017,
Abstract: 摘要 以11-巯基十一烷酸(11-MUA)为还原剂和保护剂,通过一步水热法合成了具有强烈荧光的水溶性金纳米簇(AuNCs),基于Cu2+修饰的AuNCs@11-MUA构建了"关-开"型荧光探针用于多巴胺(DA)的选择性、高灵敏检测.向AuNCs@11-MUA溶液中加入Cu2+离子后,AuNCs@11-MUA的荧光发生猝灭,体系的荧光信号处于"关闭"状态.在DA存在下,由于DA与Cu2+具有更强的结合力,形成比Cu2+/AuNCs@11-MUA复合体更稳定的络合物,可将Cu2+从AuNCs@11-MUA表面移除下来,从而使其荧光得以恢复,体系的荧光信号呈"打开"状态.AuNCs@11-MUA探针的荧光恢复程度与DA的浓度在2.0×10-7~5.0×10-5 mol/L范围呈良好的线性关系,检出限为8.0×10-8 mol/L(S/N=3).将该探针应用于人血清和尿液中DA的检测,回收率为93.2%~97.3%,相对标准偏差RSD<4.08%,表明该方法可应用于人体内多巴胺的检测
共轭聚合物荧光“开-关”的构建及对S-腺苷甲硫氨酸的分子识别与检测  [PDF]
李慧芝,翟涛,张广友,裴梅山
分析化学 , 2014, DOI: 10.11895/j.issn.0253-3820.140073
Abstract: 以Pb2+和S-腺苷甲硫氨酸(S-Adenosylmethionine,SAM)与聚3-(1-(2-三乙胺乙酰基)哌啶-4-亚甲基)噻吩(poly3-{[1-(2-hydrazino-2-oxoethyl)piperidin-4-ylidene]methyl}thiophene,PMTH)构建荧光开关,当有Pb2+存在时,PMTH与Pb2+之间发生作用,荧光猝灭,即为荧光“关”;当Pb2+-PMTH体系中加入SAM时,SAM能够与Pb2+形成更稳定的配合物,使PMTH的荧光恢复,即为荧光“开”。通过PMTH的荧光开关信号,成功建立了识别和检测SAM的新方法。研究了在水-乙醇(4:1,V/V)溶液中Pb2+和PMTH与SAM相互作用对荧光光谱的影响。本方法具有很好的灵敏度和选择性,常见氨基酸和金属离子对SAM的检测无影响,在最佳实验条件下,SAM的浓度在1.0×10-8~2.0×10-6mol/L范围内与相对荧光强度呈线性相关,线性回归方程为ΔI=68.51+72.32C(μmol/L),相关系数r=0.9982,检出限为8.72×10-9mol/L;本方法已成功用于SAM检测。
地域社会学:何以可能?何以可为?——以战后日本城乡“过密—过疏”问题研究为中心  [PDF]
田毅鹏
社会学研究 , 2012,
Abstract: 20世纪60年代以降,以战后都市过密化和乡村过疏化为背景,日本兴起了以研究地域社会结构、集团构成以及人类行动为主要内容的地域社会学。地域社会学试图超越农村社会学和城市社会学的界限,以城市化背景下“生活社会化”为基本理论前提,以乡村过疏化为研究重点,围绕着“地域生活”、“地域组织团体”、“地域格差”、“地域政策”、“新公共性构建”等问题展开研究,建立起“结构分析”的学科分析范式。地域社会学通过对城乡过密—过疏进程的研究,将城乡关系问题作为空间转换的核心内容,体现了其对人类社会由传统到现代转变的特别关注。在拓展社会学学科研究界限的同时,也为其走向政策应用化发挥了重要作用。
走出国有企业的人员过密化逻辑  [PDF]
李培林 ?
期刊检索-中国人口科学 , 1999,
Abstract: 企业的人员过密化,或者说隐性失业的存在,按照奥肯定律的解释,是由于厂商在雇佣成本方面的考虑,在产量减少时保留一定富余人员的成本可能低于在产量扩大时再重新雇佣和培训新工人所需的成本;科尔内虽然考虑到非经济因素的影响,但基本上也是认为囤积劳动是针对劳动短缺的选择。本文提出,在赋予国有企业就业和生活保障功能的情况下,企业就具有了利润最大化和职工福利最大化的双重目标,人员过密化是其逻辑结果。由于福利的刚性特征,要改变这种逻辑并保持社会稳定,必须建立更有效率并能提供同样保障水平的替代机制。
开孔薄板的变分原理及屈曲和过屈曲分析的有限元方法  [PDF]
杨骁,程昌钧
力学学报 , 1991, DOI: 10.6052/0459-1879-1991-2-1995-826
Abstract: 本文以开孔薄板大挠度问题的一般理论为基础,建立了以挠度w和应力函数F为未知量的变分原理,并由此建立了用于分析开孔薄板屈曲和过屈曲问题的有限单元法可以看到由于区域的多连通性,单元性质是较为复杂的。
Advancement of CMOS Schmitt Trigger Circuits  [cached]
Wassan M. Kader,Haroon Rashid,Md. Mamun,Mohammad Arif Sobhan Bhuiyan
Modern Applied Science , 2012, DOI: 10.5539/mas.v6n12p51
Abstract: Schmitt triggers are electronic comparators that are widely used to enhance the immunity of circuits to noise and disturbances and are inherent components of various emerging applications. Conventional Schmitt triggers, composed of operational amplifiers, suffer from some inevitable drawbacks which are not prominent in CMOS Schmitt triggers. In this paper, a review on the advancement of Schmitt trigger circuits are illustrated in different literatures is discussed with their merits and demerits.
New Schmitt Trigger with controllable hysteresis using Dual Control Gate-Floating Gate Transistor (DCG-FGT)  [cached]
abderrezak marzaki
International Journal of Reconfigurable and Embedded Systems (IJRES) , 2012, DOI: 10.11591/ijres.v2i1.2137
Abstract: This paper presents different low voltage adjustable CMOS Schmitt trigger using DCG-FGT transistor. Simple circuits are introduced to provide flexibility to program the hysteretic threshold in this paper. The hysteresis can be controlled accurately at a large voltage range. The proposed Schmitt trigger have been designed using 90nm 1.2V CMOS technology and simulated using Eldo with PSP device models. The simulation results show rail-to-rail operation and adjustable switching voltages VTH- (low switching voltage) and VTH+(high switching voltage).
Schmitt-Vogel type lemma for reductions  [PDF]
Kyouko Kimura,Naoki Terai,Ken-ichi Yoshida
Mathematics , 2009,
Abstract: The lemma given by Schmitt and Vogel is an important tool in the study of arithmetical rank of squarefree monomial ideals. In this paper, we give a Schmitt-Vogel type lemma for reductions as an analogous result.
A teoria da democracia de Carl Schmitt
Joel Thiago Klein
Princípios : Revista de Filosofia , 2009,
Abstract: The paper deals with Carl Schmitt’s theory of democracy, aiming at presenting its merits and deficiencies. The argumentation is divided into two parts. Initially, the thesis that Schmitt’s theory works within two different levels, i.e., a conceptual one, which is essentially analytical, and a phenomenal one, which according to him would be descriptive only, is sustained. At this point, Schmitt’s theory of democracy and its critique of parliamentary democracy can be better understood. Finally, some criticisms against Schmitt’s position are presented.
Louis Nirenberg and Klaus Schmitt: The joy of differentialequations  [cached]
Jean Mawhin
Electronic Journal of Differential Equations , 2007,
Abstract: A tribute to Louis Nirenberg for his 80th birthday anniversary and to Klaus Schmitt for his 65th birthday anniversary.
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