全文获取类型
收费全文 | 128篇 |
免费 | 0篇 |
国内免费 | 8篇 |
专业分类
化学工业 | 17篇 |
金属工艺 | 3篇 |
机械仪表 | 1篇 |
能源动力 | 16篇 |
无线电 | 70篇 |
一般工业技术 | 20篇 |
原子能技术 | 6篇 |
自动化技术 | 3篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 10篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2017年 | 13篇 |
2016年 | 10篇 |
2015年 | 7篇 |
2014年 | 7篇 |
2013年 | 8篇 |
2012年 | 10篇 |
2011年 | 5篇 |
2010年 | 2篇 |
2009年 | 8篇 |
2008年 | 5篇 |
2007年 | 8篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有136条查询结果,搜索用时 15 毫秒
11.
We consider effects of binding and self-trapping of particles added or excited over the insulating state of an antiferromagnetic
Mott insulator. The state of an electron or a hole (as appears in ARPES), or of their bound pair (as appears in optics) can
be modified by interactions with collective degrees of freedom—deformations of the lattice or of the spin environment. The
resulting self-localized state lowers the total particle energy, enhances its effective mass and splits off the electronic
level below the nominal insulating gap. We show theoretically that the effect is particularly pronounced for states near the
antinodal (π, 0) type point of the Brillouin zone of the CuO2 because of proximity to the van Hove singularity. We study also the van Hove enhancements for bound states of the electron
with neutral and charged impurities and for inter-gap excitons. The results are clearly important for undoped and electron-doped
cuprates where the antinodal points correspond to the spectrum bottom for electrons. The effect is indirectly important for
lightly hole-doped cuprates concerning the ARPES spectrum transfer between the nodal arcs and the dark antinodal regions. 相似文献
12.
Photocarrier generation in organic thin-film solar cells with an organic heterojunction 总被引:1,自引:0,他引:1
Takahiro Osasa Shuhei Yamamoto Yohei Iwasaki Michio Matsumura 《Solar Energy Materials & Solar Cells》2006,90(10):1519-1526
Photocurrent–voltage characteristics for organic solar cells with a heterojunction formed between copper phthalocyanine and a perylene derivative (or C60) were studied. The photocurrent was observed under both reverse and forward biases. From the analysis of the photocurrent action spectra, the origin of the reverse photocurrent was attributed to the excitons formed in both the organic layers, whereas that of the forward photocurrent was attributed to the excitons formed in the perylene derivative (or C60) layer. The photocurrent density under reverse bias increased at higher temperatures, suggesting that the charge recombination possibility was lowered at higher temperatures. On the basis of the time responses of the photocurrents observed after pulsed photoirradiation, the charge separation and transport processes are discussed. 相似文献
13.
Vertically aligned ZnO nanowire arrays in Rose Bengal-based dye-sensitized solar cells 总被引:1,自引:0,他引:1
Basudev Pradhan Sudip K. Batabyal Amlan J. Pal 《Solar Energy Materials & Solar Cells》2007,91(9):769-773
We fabricate dye-sensitized solar cells (DSSC) using vertically oriented, high density, and crystalline array of ZnO nanowires, which can be a suitable alternative to titanium dioxide nanoparticle films. The vertical nanowires provide fast routes or channels for electron transport to the substrate electrode. As an alternative to conventional ruthenium complex, we introduce Rose Bengal dye, which acts as a photosensitizer in the dye-sensitized solar cells. The dye energetically matches the ZnO with usual KII2 redox couple for dye-sensitized solar cell applications. 相似文献
14.
Conventional heterojunction organic photovoltaic cells typically involve the deposition of the electron donor layer (or donor–acceptor blend) on top of a transparent anode, with the cathode deposited last. Inverting the structure and deposition sequence usually worsens the performance characteristics, except device lifetime. We compare conventional (SubPc/C60) and inverted (C60/SubPc) junctions, the latter exhibiting a power conversion efficiency of 3.5%. We also find a significant trade-off between the open circuit voltage and short circuit photocurrent, potentially attributable to the formation of a C60/ITO Schottky junction, and a change from exciton-quenching to exciton-blocking behavior of the SubPc:MoOX interface in inverted devices. 相似文献
15.
Despite their merits of high efficiency and environmental friendliness, phosphor based white organic light-emitting diodes (WOLEDs) for commercial applications still face tough challenges of efficiency roll-off and color stability. Herein, we fabricated high-efficiency phosphor WOLEDs with extremely low roll-off and stable white emission by employing mixed spacer layer between the two complementary emissions as well as mixed host in the orange layer. The strategic exciton management in our proposed device structure greatly balanced the transport of charge carriers due to the excellent exciton manipulation of the mixed spacer, and significantly suppressed the exciton quenching owing to the extended exciton recombination region, which significantly minimized the efficiency roll-off of the fabricated WOLEDs. The resulting phosphor WOLED exhibited the maximum current efficiency (CE) and power efficiency (PE) of 47.5 cd A−1 and 44.7 lm W−1, respectively, and the CE still had 43.1 cd A−1 at 5000 cd m−2, showing a suppressed efficiency roll-off of only 9.2%. Additionally, the device achieved fairly stable spectra over a wide range of luminance with suitable CIE coordinates for indoor lighting and outdoor displays. 相似文献
16.
A novel series of soluble conjugated random and alternating copolymers derived from 9,9-dioctylfluorene (FO) and 1,1-dimethyl-2,3,4,5-tetraphenylsilole (PSP) were synthesized by Suzuki coupling reactions. The feed ratios of FO to PSP were 95:5, 90:10, 85:15, 70:30, and 50:50. Chemical structures and optoelectronic properties of the copolymers were characterized by elemental analysis, NMR, UV absorption, cyclic voltammetry, photoluminescence (PL), and electroluminescence (EL). The elemental analyses of the copolymers indicated that FO and PSP contents in the copolymers were very close to that of the feed compositions. Unlike the weak PL emission of PSP small molecules in a solution, PFO-PSP solutions could emit strong lights with PL quantum yields between 13 and 30%, indicating that the incorporation of the PSP into the conjugated rigid main chain could greatly restrict the rotations of the phenyl groups of the PSP units even in a solution. Compared with the solution PL, complete PL excitation energy transfer from the PFO segments to the PSP units could be achieved by film PL at lower PSP content. The films of the copolymers exhibited high absolute PL quantum yields between 55 and 84%. EL devices with a configuration of ITO/PEDOT/PFO-PSP/Ba/Al demonstrated that the PSP units could serve as powerful exciton traps, giving exclusively pure green EL emissions. A maximum external quantum efficiency of 1.51% was achieved using the PFO-PSP15 as the emissive layer. 相似文献
17.
Claudia Malerba Francesco Biccari Cristy Leonor Azanza RicardoMirco D’Incau Paolo ScardiAlberto Mittiga 《Solar Energy Materials & Solar Cells》2011,95(10):2848-2854
The optical absorption coefficient of thin film and bulk Cu2O at room temperature is obtained from an accurate analysis of their transmittance and reflectance spectra. These absorption spectra are modeled, together with the low temperature data reported in the literature, using an analytical expression to assess and quantify the role of the different absorption mechanisms. The results suggest that direct forbidden transitions and indirect transitions play an almost equally relevant role. A table of the optical constants of Cu2O single crystal is given for reference. 相似文献
18.
Yuichi Yamasaki Harumi Asami Takashi Isoshima Itaru Kamiya Masahiko Hara 《Science and Technology of Advanced Materials》2013,14(6):519-522
A single chromophore detection using video-microscopy is one of the latest methodologies to reveal unique characteristics, which could not be obtained from ensemble measurements. Among many kinds of subjects, dynamic optical properties observed in colloidal semiconductor nanoparticles are attractive and important not only for the basis of photo-physics but also for application studies, e.g. biological labeling, electronic devices. In this study, fluorescence video-microscopy was performed on cadmium selenide (CdSe) quantum dots (QDs) spin-coated on a glass substrate. From single CdSe QDs detection, emissions at wavelengths separated over 60 nm were observed for the first time. This spectral feature was attributed to the existence of double-emissive relaxation processes in CdSe QDs. Photoluminescence intermittency was also observed both from relaxation processes. Fluorescence video-microscopy, which was advanced in biology, can be applicable for the real-time monitoring of dynamic properties in semiconductor photo-physics. 相似文献
19.
K.A.S. Araujo P.S.S. Guimarães L.A. Cury L. Akcelrud D. Sanvitto M. De Giorgi M. Valadares H.D.R. Calado 《Organic Electronics》2012,13(12):2843-2849
Optical properties of poly(n-vinylcarbazole) (PVK) thin films are revisited. Steady-state emission spectra put in evidence a strong red band whose intensity increases with decreasing temperature when the solid state PVK film is excited by a continuous 375 nm laser line. This red band is assigned to the emission from PVK aggregate states which act as trap states for the monomeric PVK triplet high energy (blue) excitons. At the same low temperatures, these trap states can be avoided when the excitation of the PVK film is made by a 355 nm pulsed laser line with 10 Hz repetition rate. The red band was also observed to compete with the emission of guest poly(3-octadecylthiophene) (PODT) molecules in a PVK/PODT sequential bilayer structure. Different optical geometries enabled us to show that the exciton energy transfer effect from PVK donor to PODT acceptor states dominates the scenario in the bilayer structure, suppressing almost completely the trap state emissions. 相似文献
20.
We study external quantum efficiency (ηEQE) roll-off in organic light-emitting diodes (OLEDs) using thermally-activated delayed fluorescence (TADF) of 4,5-di (9H-carbazol-9-yl) phthalonitrile (2CzPN). Using 2CzPN intramolecular rate constants from optical analyses, we construct an exciton quenching model incorporating intersystem crossing and reverse intersystem crossing. The model indicates that singlet–triplet annihilation and triplet–triplet annihilation dominate ηEQE roll-off because of the relatively long 2CzPN triplet lifetime of 273 μs. This work yields a method to relax the exciton quenching process in TADF based OLEDs. 相似文献