全文获取类型
收费全文 | 115篇 |
免费 | 6篇 |
国内免费 | 16篇 |
专业分类
化学 | 69篇 |
晶体学 | 7篇 |
力学 | 2篇 |
数学 | 13篇 |
物理学 | 46篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 10篇 |
2013年 | 6篇 |
2012年 | 10篇 |
2011年 | 9篇 |
2010年 | 8篇 |
2009年 | 17篇 |
2008年 | 6篇 |
2007年 | 5篇 |
2006年 | 10篇 |
2005年 | 7篇 |
2004年 | 8篇 |
2003年 | 5篇 |
2002年 | 1篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
排序方式: 共有137条查询结果,搜索用时 15 毫秒
101.
The liquid crystal (LC) alignment behaviors of LC cells fabricated with cellulose acetate films were investigated. These polymer films exhibited good optical transparency in the visible light region (400–700 nm). For example, transmittance value (92%) of the cellulose acetate film onto glass substrate at 550 nm is better that (89%) of the polyimide (PI) film, the most commonly used LC alignment layers. These LC cells fabricated with the rubbed cellulose acetate films showed the homogeneous planar LC alignment with parallel direction with respect to the rubbing direction. The electro-optical characteristics of the LC cells made from the cellulose acetate films such as response time were as good as those fabricated from rubbed PI films. 相似文献
102.
We prepared blend alignment layer based on 4-ethylphenoxymethyl-substituted polystyrene (P4EP) and polystyrene containing 7-hydroxycoumarin (P7COU) for liquid crystal (LC) alignment. Stable and uniform vertical LC cells having pretilt angles adjustable from 90° to 81.2° were obtained from these polystyrene films having molar contents of P4EP and P7COU in the ranges of 100–70 and 0–30 mol%, respectively. The LC alignment behavior was well correlated with the wettability of the polymer films. These polystyrene blends having good solubility in many organic solvents and their films having low process (curing) temperature can be candidates for LC alignment layer in the flexible display. This study contributes to the latest efforts to develop new alignment layers for pretilt angle control. 相似文献
103.
Organic field-effect transistors are of great importance to electronic devices. With the emergence of various preparation techniques for organic semiconductor materials, the device performance has been improved remarkably. Among all of the organic materials, single crystals are potentially promising for high performances due to high purity and well-ordered molecular arrangement. Based on organic single crystals, alignment and patterning techniques are essential for practical industrial application of electronic devices. In this review, recently developed methods for crystal alignment and patterning are described. 相似文献
104.
Surface enhanced Raman scattering (SERS) spectroscopy was first utilized to study the photo-orientation behaviour of the photoreactive groups on a novel photo-alignment film surface and elucidate the generation mechanism of pretilt angle. The novel photo-alignment film was prepared by spin-coating a solution of ladderlike polysiloxane (LPS) bearing dual photoreactive group on an ITO surface and by irradiation with linear-polarized ultraviolet (LPUV) light. A Si-H terminal compound (M) containing an identical photosensitive part has been used to fabricate a model film for SERS investigation. 相似文献
105.
Csenki L Alm E Torgrip RJ Aberg KM Nord LI Schuppe-Koistinen I Lindberg J 《Analytical and bioanalytical chemistry》2007,389(3):875-885
In metabolic profiling, multivariate data analysis techniques are used to interpret one-dimensional (1D) 1H NMR data. Multivariate data analysis techniques require that peaks are characterised by the same variables in every spectrum.
This location constraint is essential for correct comparison of the intensities of several NMR spectra. However, variations
in physicochemical factors can cause the locations of the peaks to shift. The location prerequisite may thus not be met, and
so, to solve this problem, alignment methods have been developed. However, current state-of-the-art algorithms for data alignment
cannot resolve the inherent problems encountered when analysing NMR data of biological origin, because they are unable to
align peaks when the spatial order of the peaks changes—a commonly occurring phenomenon. In this paper a new algorithm is
proposed, based on the Hough transform operating on an image representation of the NMR dataset that is capable of correctly
aligning peaks when existing methods fail. The proposed algorithm was compared with current state-of-the-art algorithms operating
on a selected plasma dataset to demonstrate its potential. A urine dataset was also processed using the algorithm as a further
demonstration. The method is capable of successfully aligning the plasma data but further development is needed to address
more challenging applications, for example urine data.
Figure Traces of NMR peaks visualizing the Generalized Fuzzy Hough Transform (GFHT) method for elucidating peak correspondence between
samples. The spectra are sorted according to one shift sensitive peak and reveals that other peaks exhibit a similar shift
pattern. This pattern(s) can now be searched for using the GFHT. The red and black spectra in the figure are the most shifting
spectra (top and bottom), by following the GFHT traces peak correspondence is easily established although peaks change spatial
location
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
106.
A thieno [3,2-b] thiophene-based planar liquid crystal molecule, C12-PTTT, which possesses the characteristics of an organic field-effect transistor (OFET), was synthesised and its mesomorphic properties were studied by polarising optical microscopy and differential scanning calorimetry. A wide temperature range for a highly oriented smectic phase was observed. OFET devices made under various conditions, such as self-assembled monolayer treatment and alignment treatment, and with micro-channel structures, were fabricated to measure the electrical properties. Among different OFET device conditions, the best electric carrier mobility for C12-PTTT was 0.038 cm2?V?1?s?1. 相似文献
107.
We chose a series of isoindigo-based conjugated polymer(ⅡDDT,ⅡDDT-C3 and ⅡDDT-C4) with different length of side chains and bifurcation positions to investigate the relationship between the degree of alignment and the length of side chains and bifurcation positions.We found that the dichroic ratio was increased from 2.37 to 5.23 when the side chain was longer and the bifurcation position was away from the backbone.The π-π stacking distance was decreased from 3.67 A to 3.61 A when the bifurcation position was away from the backbone because of its smaller hindrance and the d-spacing of the(100)was increased from 20.06 A to 25.21 A when the side chain was longer.All the polymers were adopted an edge-on orientation with the backbone paralleled with the long axis of fibers.The weak interaction of side-chain in ⅡDDT-C4 was beneficial for the molecules being rearranged in parallel during the contact line receding and the strong n-n interaction could accelerate the interchain assembly of the parallel molecules through π-π interaction to form aligned fibers. 相似文献
108.
109.
HL-2A装置ECRH的微波强度分布测量与分析 总被引:1,自引:1,他引:0
利用红外热像仪测量微波传播路径上的三个不同距离截平面上的微波强度分布,计算出辐射图的一阶及二阶矩并重建相位信息,可以确定微波波束的强度分布和准直度。使用该方法对两套ECRH系统传输线进行了定量的分析,获得了微波强度分布均为高斯分布、7m 3#传输线的微波束线准直度为0.05°、6m 4#传输线微波束线准直度为0.14°的结果。 相似文献
110.
David M. Boudreau H. Henning Winter C. Peter Lillya Richard S. Stein 《Rheologica Acta》1999,38(6):503-513
Orientational changes in monodomains of flow-aligning liquid crystals, 4-n-pentyl-4′-cyanobiphenyl and N-(4-methoxybenzylidene)-4-butylaniline, were studied during shear and recovery in a linear shearing device fitted to an optical
microscope. Planar alignment (director in the shear plane) allows the study of twist effects and was generated by strong planar
anchoring at the walls with orientations in a range of 0–90° with the shear direction. While being held back by the anchoring
walls, shear caused the bulk director to rotate towards a steady-state alignment angle in the shear direction (Leslie angle
θL). The transient director rotation was observed with conoscopy. It was found that increasing the initial alignment towards
the vorticity direction increased the measured θL. Upon stopping the flow, the bulk director returned to its initial state. With initial alignment orientation changing from
parallel to perpendicular to the flow direction, the rate of the twist-driven recovery process increases. This rate increase
is not seen in the splay-driven recovery which is constant and consistently faster than twist-driven recovery at all orientations
studied.
Received: 10 December 1998/Accepted: 7 June 1999 相似文献