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在微流控芯片上构建多维分离系统,为蛋白质组学研究提供了一个有发展前景的高效分离分析技术平台。本文介绍了二维芯片电泳系统耦联模式选取及正交性评价的方法;综述了针对蛋白质/多肽分离分析的各种耦联模式微流控二维芯片电泳分析系统,如胶束电动力学色谱(MEKC)与毛细管区带电泳(CZE),开管电色谱(OECE)与CZE,等电聚焦(IEF)与CZE, IEF与SDS毛细管凝胶电泳(CGE), SDS-CGE与MEKC等。特别对二维电泳芯片切换接口的类型进行了分类,探讨了用于微流控二维芯片电泳系统的检测技术,并展望了微流控二维电泳芯片在蛋白质组学研究中的应用前景和发展方向。 相似文献
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研制了一种基于激光诱导荧光检测方法的微流控芯片分析仪。该分析仪使用玻璃基质聚二甲基硅氧烷(PDMS)微流控芯片,可一次性进行12通道的电泳分离实验。仪器采用共聚焦式光路结构,并可通过检测由微流控芯片反射的激光信息,控制步进电机实现芯片的自动精确定位。实验结束自动保存数据,绘制分离图谱。。对9种不同长度的50 bp DNA Ladder片段进行电泳分离及数据分析,耗时在5 min内,且分离效果良好。 相似文献
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毛细管电泳微流控芯片分离-激光诱导荧光(LIF)检测DNA片段是近年来微流控分析系统中研究得较为成功的领域,该方向的研究成果极大地促进了微流控分析系统的发展.在相关的报道中,待分析样品和系统运行溶液仍然主要使用手工操作. 相似文献
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微流控芯片中超微电极的制作及其在芯片-电化学检测中的应用 总被引:8,自引:0,他引:8
设计并制作了集成有超微电极的玻璃微流控芯片.在电化学检测芯片1(EC-1)中,以光刻方法制作13μm宽的Pt超微电极,距分离管道末端30μm,优化电极体系和分离电压,检测了电泳分离的神经递质.在电化学检测芯片2(EC-2)中,制作7μm宽的超微电极,在其上游集成城墙式的膜结构,进一步腐蚀后的膜厚度为10μm,具有良好的导电性和散热性能,成功地将高压电场截至在超微电极之前,具有进一步应用于电化学检测的能力. 相似文献
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自从1995年Mathies[1]首次将微流控芯片毛细管凝胶电泳用于基因测序研究以来,DNA片段的分离已成为微流控芯片应用的重要领域之一.最早应用于DNA分析的微流控芯片是玻璃芯片,聚合物微流控芯片以其品种多、成本低、易于加工,与玻璃芯片相比具有封接温度大大降低,微通道内电渗流显著减小等特点,已被成功应用于DNA片段的分离[2,3]. 相似文献
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Park JB Jaeckel B Parkinson BA 《Langmuir : the ACS journal of surfaces and colloids》2006,22(12):5334-5340
Nanometer-scale holes have been fabricated on the surfaces of the semiconducting transition metal dichalcogenides (TMDCs) molybdenum ditelluride (MoTe2) and molybdenum disulfide (MoS2) by applying voltage pulses from the tip of a scanning tunneling microscope (STM) operating in ultrahigh vacuum (UHV). It was found that the tip geometry (tip shape and sharpness) influences the formation and structure of the atomic-scale nanostructures. Threshold voltage ranges for the surface modification of MoTe2 (3.0 +/- 0.3 V) and MoS2 (3.4 +/- 0.3 V) were determined. Negative sample voltage pulses applied to a p-type MoTe2 surface produced much larger and deeper nanometer-scale holes when compared with those produced by positive voltage pulses. The existence of threshold voltages and the pulse polarity dependence of nanostructure fabrication suggests that an electric field evaporation mechanism is applicable. Support for this mechanism was obtained by nanostructuring metallic TMDC NbSe2, where both the produced features and the threshold voltages (3.0 +/- 0.3 V) were similar for both positive and negative voltage pulses. 相似文献
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Lena Ganda Saptalena Klaus Kerpen Andriy Kuklya Ursula Telgheder 《International Journal for Ion Mobility Spectrometry》2012,15(2):47-53
Mixtures of 12 known volatile metabolites of Escherichia coli (2,5-dimethyltetrahydrofuran, dimethyl disulfide, 2-heptanone, 2,5-dimethylpyrazine, benzaldehyde, dimethyl trisulfide, 2-nonanone,
nonanal, decanal, 2-undecanone, indole, and 2-tridecanone) were prepared from internal standards in water. The headspace gases
were then analyzed using microAnalyzer™, a miniaturized Gas Chromatography-Differential Mobility Spectrometry (GC-DMS) system.
Differential mobility spectra showed monomer peaks of the analytes with the observed retention times below 3 min. Dispersion
voltages, determining the dependence of signal intensities and compensation voltages of each analyte on the applied radio
frequency (RF) voltages, were recorded for positive and negative modes. It was found that at increasing RF voltages the monomer
peaks of compounds of lower molecular masses tend to shift to more negative compensation voltages; whereas, those of higher
molecular masses tend to shift to more positive compensation voltages. The shift results in increase separation among each
peak. The signal intensities for all peaks, however, tend to decrease at higher RF voltages. The RF voltage which gave optimum
peaks separation and signal resolution was 1,200 V (corresponds to 24 kV/cm). This study demonstrates the potential of microAnalyzer™
as an integrated gas chromatograph detector for a preliminary screening system in the on-site detection of E. coli in water. The operational principle of the instrument is also presented in this study. 相似文献
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A novel three rod (tripole) ion optic to which three AC voltages with symmetrically delayed phase shifts were applied to each electrode. We studied its ion guiding, focusing, and mass filtering capabilities by SIMION ver. 7.0 computer simulations. An electric field mathematical model was developed to calculate the pseudopotential of the tripole radial AC force. The tripole showed stable ion guiding for wide ranges of AC amplitude; better collisional focusing than hexapole and octapole and similar focusing as quadrupole (rod pole). Also, the ion optic clearly showed interesting mass filtering potential when the phase shift was asymmetrically delayed. The symmetric shape of the pseudopotential field explained the tripole ion guiding and focusing capabilities. For mass filtering, the pseudopotential was asymmetric and its effect was balanced with DC voltage to separate the ions, depending in their masses. The resolution was much lower than quadrupole but useful when rough filtering was required. 相似文献
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研究了直流电场对含LiClO4的聚氧化乙烯(PEO)400与环氧树脂形成的液晶态互穿网络高分子忆禽子导体的电导率的影响。在室温至90℃范围内,电导率随外加电压增加面降低。外加电压越高,对电导率变化的影响越大。 相似文献
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Nanoscale characterization of acid and redox properties of Keggin-type heteropolyacids (HPAs) with different heteroatoms, H(n)MW(12)O(40) (M = P, Si, B, Co), was carried out by scanning tunneling microscopy (STM) and tunneling spectroscopy (TS) in this study. HPA samples were deposited on highly oriented pyrolytic graphite surfaces to obtain images and tunneling spectra by STM before and after pyridine adsorption. All HPA samples formed well-ordered 2-dimensional arrays on graphite before and after pyridine exposure. NDR (negative differential resistance) peaks were observed in the tunneling spectra. Those measured for fresh HPA samples appeared at less negative voltages with increasing reduction potential of the HPAs and with increases in the electronegativity of the heteroatom, but with decreases in the overall negative charge of the heteropolyanions. These results support the conclusion that more reducible HPA samples show NDR behavior at less negative applied voltages in their tunneling spectra. Introduction of pyridine into the HPA arrays increased the lattice constants of the 2-dimensional HPA arrays by ca. 6 A. Exposure to pyridine also shifted NDR peak voltages of H(n)MW(12)O(40) (M = P, Si, B, Co) samples to less negative values in the TS measurements. The NDR shifts of HPAs obtained before and after pyridine adsorption were correlated with the acid strengths of the HPAs, suggesting that tunneling spectra measured by STM could serve to probe acid properties of HPAs. These results show how one can relate the bulk acid and redox properties of HPAs to surface properties of nanostructured HPA monolayers determined by STM. 相似文献
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A simple method to perform selective on-line preconcentration of protein samples in capillary electrophoresis (CE) is described. The selectivity, based on protein electrophoretic mobility, was achieved by controlling electroosmotic flow (EOF). A short section of dialysis hollow fiber, serving as a porous joint, was connected between two lengths of fused silica capillary. High voltage was applied separately to each capillary, and the EOF in the system was controlled independently of the local electric field intensity by controlling the total voltage drop. An equation relating the EOF with the total voltage drop was derived and evaluated experimentally. On-line preconcentration of both positively charged and negatively charged model proteins was demonstrated without using discontinuous background electrolytes, and protein analytes were concentrated by approximately 60-200-fold under various conditions. For positively charged proteins, positive voltages of the same magnitude were applied at the free ends of the connected capillaries while the porous joint was grounded. This provided a zero EOF in the system and a non-zero local electric field in each capillary to drive the positively charged analytes to the porous joint. CE separation was then initiated by switching the polarity of the high voltage over the second capillary. For negatively charged proteins, the procedure was the same except negative voltages were applied at the free ends of the capillaries. Mobility-based selective on-line preconcentration was also demonstrated with two negatively charged proteins, i.e. beta-lactoglobulin B and myoglobin. In this case, negative voltages of different values were applied at the free ends of the capillaries with different values, which provided a non-zero EOF in the system. The direction of EOF was the same as that of the electrophoretic migration velocities of the protein analytes in the first capillary and opposite in the second capillary. By controlling the EOF, beta-lactoglobulin B, which has a higher mobility, could be concentrated over 150-fold with a 15 min injection while myoglobin, which has a lower mobility, was eliminated from the system. 相似文献
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Responses of surface stabilized antiferroelectric liquid crystals (SSAFLCs) to an electric field are simulated based on a model of the AFLC phase. The apparent tilt angle, the polarization reversal current and the optical transmission under applied triangular wave voltages are calculated. The results obtained systematically explain the experimental observations fairly well. The effects of parameters such as amplitude and frequency of applied voltages, an antiferroelectric coupling parameter and surface anchoring strength on these phenomena are discussed. 相似文献
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Cheng Xue-Feng Li Jie Hou Xiang Zhou Jin He Jing-Hui Li Hua Xu Qing-Feng Li Na-Jun Chen Dong-Yun Lu Jian-Mei 《中国科学:化学(英文版)》2019,62(6):753-760
Multilevel resistance random access memories(RRAMs) are intensively studied due to their potential applications in high density information storage. However, the low ternary device yields and high threshold voltages based on current materials cannot meet the requirement for applications. Improvement via material innovation remains desirable and challenging. Herein,five one-dimensional conjugated coordination polymers were synthesized via the reaction between metal ions(Zn~(2+), Cu~(2+), Ni~(2+),Pt~(2+) and Pd~(2+)) and 2,5-diaminobenzene-1,4-dithiol(DABDT) and fabricated into RRAM devices. The as-fabricated ternary memories have relatively low threshold voltages(V_(th1):-1 to-1.4 V, V_(th2):-1.8 to-2.2 V). Their ternary device yields were improved from 24% to 56%. The first and the second resistance switches are interpreted by the space charge limited current(SCLC) and grain boundary depletion limited current(GBLC) modes, respectively. The Pd-DABDT, which is of planar structure,smaller band gap and better crystallinity than others, shows the best performance among these five polymers. Our work paves a simple and efficient way to optimize the performance of ternary RRAM devices employing one-dimensional hybrid materials. 相似文献
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Weir MP Heriot SY Martin SJ Parnell AJ Holt SA Webster JR Jones RA 《Langmuir : the ACS journal of surfaces and colloids》2011,27(17):11000-11007
We have investigated a novel method of remotely switching the conformation of a weak polybase brush using an applied voltage. Surface-grafted polyelectrolyte brushes exhibit rich responsive behavior and show great promise as "smart surfaces", but existing switching methods involve physically or chemically changing the solution in contact with the brush. In this study, high grafting density poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes were grown from silicon surfaces using atom transfer radical polymerization. Optical ellipsometry and neutron reflectivity were used to measure changes in the profiles of the brushes in response to DC voltages applied between the brush substrate and a parallel electrode some distance away in the surrounding liquid (water or D(2)O). Positive voltages were shown to cause swelling, while negative voltages in some cases caused deswelling. Neutron reflectometry experiments were carried out on the INTER reflectometer (ISIS, Rutherford Appleton Laboratory, UK) allowing time-resolved measurements of polymer brush structure. The PDMAEMA brushes were shown to have a polymer volume fraction profile described by a Gaussian-terminated parabola both in the equilibrium and in the partially swollen states. At very high positive voltages (in this study, positive bias means positive voltage to the brush-bearing substrate), the brush chains were shown to be stretched to an extent comparable to their contour length, before being physically removed from the interface. Voltage-induced swelling was shown to exhibit a wider range of brush swelling states in comparison to pH switching, with the additional advantages that the stimulus is remotely controlled and may be fully automated. 相似文献