全文获取类型
收费全文 | 86篇 |
免费 | 25篇 |
国内免费 | 18篇 |
专业分类
化学 | 59篇 |
力学 | 5篇 |
数学 | 4篇 |
物理学 | 61篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 1篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 5篇 |
2016年 | 2篇 |
2015年 | 6篇 |
2014年 | 12篇 |
2013年 | 4篇 |
2012年 | 15篇 |
2011年 | 9篇 |
2010年 | 7篇 |
2009年 | 11篇 |
2008年 | 3篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 5篇 |
2004年 | 8篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有129条查询结果,搜索用时 46 毫秒
11.
12.
应用水热法制备了注射器样纳米结构氧化锌样品,室温下测量其真空场发射特性.根据测量数据,基于Fowler-Nordheim方程,估算了场发射效应增强因子,观察到增强因子随外加电压增加取值的两阶段性;结合样品的光致发光谱和能量散射谱,应用半导体材料中强场效应理论,结合场发射电流密度测量系统的串联电路等效,研究样品中空位对场发射特性影响机理.结果表明,制备过程中形成的锌、氧空位,在样品中产生了相当于杂质态的缺陷能级,缺陷能级与样品形貌共同作用,使样品较大的增强因子随场强增加而阶跃性下降.最后,用电化学沉淀法和气
关键词:
场发射
强场效应
缺陷态
串联等效 相似文献
13.
We investigate quantum dot arrays and their application to quantum computation. The arrays analyzed contain a total of a few operating electrons with constant tunneling between the dots. We construct quantum two-level systems near the ground state with a large energy separation to the remainder of the states and with the electrostatic interaction modeled within the capacitance matrix formalism. A set of representative examples is investigated numerically. 相似文献
14.
A new electronical tuning process is proposed for a millimeterwave oscillator in slotline-technique. The circuit used for the GaAs-FET oscillator is realized by a slotline coupler-structure in which the feedback between the resonator and the transistor drain is made by help of electromagnetical field. 相似文献
15.
Ziarelli F Viel S Caldarelli S Sobieski DN Augustine MP 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2008,194(2):307-312
A capacitive coupling between a secondary radiofrequency (rf) channel and the gradient coil of a standard commercially available high resolution NMR spectrometer and probe head is described and used to introduce a low level exponentially damped rf signal near the frequency of the primary rf channel to serve as an external concentration standard, in analogy to the so-called ERETIC™ method. The stability of this inexpensive and simple to implement method, here referred to as the Pulse Into the Gradient (PIG) approach, is superb over a 14-h period and both gradient tailored water suppression and one-dimensional imaging applications are provided. Since the low level signal is introduced via the pulsed field gradient coil, the coupling is identical to that for a free induction signal and thus the method proves to be immune (within 5%) to sample ionic strength effects up to the 2 M NaCl solutions explored here. 相似文献
16.
《Electroanalysis》2018,30(5):901-909
We report in this work the development of a novel capacitance electrochemical sensors based on silicon nitride substrate (Si3N4) chemically modified with a structure of Cobalt phthalocyanine, C,C,C,C‐tetracarboxylic acid‐Polyacrylamide (Co(II)Pc‐PAA). This sensitive layer was tested with and without magnetic nanoparticles (MNP) for perchlorate ( ) detection. The developed chemical sensor with Si3N4/APTES‐MNP/Co(II)Pc‐PAA structure has shown a better performance when compared to the other structure based on Si3N4/Co(II)Pc‐PAA. Contact angle measurements (CAM) and atomic force microscopy (AFM) characterizations have been performed to characterize the functionalization of the chemical sensors surface. Under the optimized structure of the chemical sensor, electrochemical measurements were carried out using Mott‐Schottky analysis for detection within the large range of 10−10 to 10−4 M with a very low detection limit of 2×10−10 M. The chemical sensor has demonstrated a high selectivity toward when compared to other interfering anions such as Cl−, SO42−, and CO32−. The present capacitive chemical sensor is very promising for sensitive and rapid detection of for environmental applications. 相似文献
17.
Dr. Sushil Kumar Najat Maher Aldaqqa Dr. Emad Alhseinat Dr. Dinesh Shetty 《Angewandte Chemie (International ed. in English)》2023,62(35):e202302180
Recent years have seen the emergence of capacitive deionization (CDI) as a promising desalination technique for converting sea and wastewater into potable water, due to its energy efficiency and eco-friendly nature. However, its low salt removal capacity and parasitic reactions have limited its effectiveness. As a result, the development of porous carbon nanomaterials as electrode materials have been explored, while taking into account of material characteristics such as morphology, wettability, high conductivity, chemical robustness, cyclic stability, specific surface area, and ease of production. To tackle the parasitic reaction issue, membrane capacitive deionization (mCDI) was proposed which utilizes ion-exchange membranes coupled to the electrode. Fabrication techniques along with the experimental parameters used to evaluate the desalination performance of different materials are discussed in this review to provide an overview of improvements made for CDI and mCDI desalination purposes 相似文献
18.
Electrochemical Capacitive K+ EMIS Chemical Sensor Based on the Dibromoaza[7]helicene as an Ionophore for Potassium Ions Detection
下载免费PDF全文
![点击此处可从《Electroanalysis》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Moncef Tounsi Mourad Ben Braiek Abdoullatif Baraket Michael Lee Nadia Zine Miguel Zabala Joan Bausells Faouzi Aloui Béchir Ben Hassine Abderrazak Maaref Abdelhamid Errachid 《Electroanalysis》2016,28(12):2892-2899
A K+‐sensitive capacitive electrolyte‐membrane‐insulator‐semiconductor (EMIS) based on a novel dibromoaza[7]helicene ionophore has been developed. An ion‐sensitive membrane based on polyvinylchloride (PVC) doped with the ionophore was deposited on the Si3N4/SiO2/Si‐p/Cu‐Al transducer. The properties of the K+‐EMIS chemical sensor were investigated by electrochemical impedance spectroscopy (EIS). All the developed devices upon being tested have shown good sensitivity and linearity responses within the range 10?6 M to 10?1 M of potassium activity, with good selectivity over a wide variety of other cations (Na+, Li+, Cu2+, Ca2+, and Mg2+). To our knowledge, this is the first time that a capacitive field‐effect sensor has been fabricated using helicene as a carrier for K+‐detection, combined with the structure: Si3N4/SiO2/Si‐p/Cu‐Al as a transducer. 相似文献
19.
20.
A capacitive immunosensor for detection of cholera toxin 总被引:2,自引:0,他引:2
Contamination of food with biological toxins as well as their potential use as weapons of mass destruction has created an urge for rapid and cost effective analytical techniques capable of detecting trace amounts of these toxins. This paper describes the development of a sensitive method for detection of cholera toxin (CT) using a flow-injection capacitive immunosensor based on self-assembled monolayers. The sensing surface consists of monoclonal antibodies against the B subunit of CT (anti-CT), immobilized on a gold transducer. Experimental results show that the immunosensor responded linearly to CT concentrations in the range from 1.0 × 10−13 to 1.0 × 10−10 M under optimized conditions. The limit of detection (LOD) was 1.0 × 10−14 M. Two more analytical methods were employed for detection of CT using the same antibody namely, sandwich ELISA and surface plasmon resonance (SPR)-based immunosensor. The former had an LOD of 1.2 × 10−12 M and a working range from 3.7 × 10−11 to 2.9 × 10−10 M whereas, the later had an LOD of 1.0 × 10−11 M and a linearity ranging from 1.0 × 10−9 to 1.0 × 10−6 M. These results demonstrate that the developed capacitive immunosensor system has a higher sensitivity than the other two techniques. The binding affinity of CT to the immobilized anti-CT was determined using the SPR-based immunosensor and an association constant (KA) of 1.4 × 109 M−1 was estimated. 相似文献