全文获取类型
收费全文 | 150篇 |
免费 | 15篇 |
国内免费 | 1篇 |
专业分类
化学 | 7篇 |
晶体学 | 3篇 |
综合类 | 1篇 |
数学 | 7篇 |
物理学 | 148篇 |
出版年
2023年 | 1篇 |
2019年 | 1篇 |
2017年 | 1篇 |
2014年 | 1篇 |
2013年 | 1篇 |
2011年 | 1篇 |
2010年 | 4篇 |
2009年 | 28篇 |
2008年 | 27篇 |
2007年 | 20篇 |
2006年 | 13篇 |
2005年 | 10篇 |
2003年 | 12篇 |
2002年 | 5篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有166条查询结果,搜索用时 15 毫秒
151.
Ni-doped InTaO4 nanocrystallites were synthesized by a reactive pulsed laser ablation process, aiming at visible-light-operating photocatalysts. The third harmonics beam of a Nd:YAG laser was focused onto a sintered In0.9Ni0.1TaO4−δ target in mixture background gases (O2 + He). The deposited species were columnar-structured porous films consisting of primary nanocrystallites. The mean diameter of the primary nanocrystallites was 4 nm. Optical absorption characteristics, especially in low absorbance (sub-band) regions, were evaluated by photoacoustic spectroscopy. Absorption in the sub-band region decreased drastically with increasing O2 partial pressures. It is inferred that oxygen deficiencies are suppressed, because of enough oxygen vapors in the reactive background gases. An absorption band around 420 nm appeared obviously in O2 partial pressures above 5%, in the Ni-doped InTaO4 nanocrystallites. The visible region absorption band is presumably attributed to the Ni 3d-eg orbitals. In contrast, pure InTaO4 nanocrystallites showed a sharp band edge, without the visible absorption band. 相似文献
152.
Weimin Zhou Jing Zhang Yanbo Liu Guoquan Min Jianping Zhang 《Applied Surface Science》2009,255(18):8019-8022
A simple and highly effective method to the replication of soft mold based on the anodic aluminum oxide (AAO) membrane was developed. The soft mold with nanopillar arrays was composed of the toluene diluted PDMS layer supported by the soft PDMS. A water contact angle as high as 114° was achieved. The hexagonally well-order arrays of holes of nanometer dimensions, ∼100 nm pore diameter and 125 nm center-to-center pore, could be gained over large areas by UV-nanoimprint lithography (UV-NIL) with the replicated soft PDMS mold. It is expected that the developed soft mold would find applications in light emitting diodes devices. 相似文献
153.
Atsushi Yamaguchi Naoya Nakagawa Taro Sekikawa Hiroyuki Asanuma 《Applied Surface Science》2009,255(24):9864-9868
We performed the transient absorption measurement and the first rate equation (RE) analysis for cis isomer of 4-carboxy-2′,6′-dimethylazobenzene to clarify the quantitative difference between the photoisomerization process and the thermal relaxation process from the excited state. The RE analysis enabled us to determine the cis-to-trans photoisomerization rate per each pump pulse to be 3% under the condition of the 430 nm, 150 fs pump pulse with energy of 200 nJ. Moreover, the signal due to the yielded trans molecules appearing in the transient absorption was assigned from the following observed result: the transient absorbance change at the 380 nm probe mostly decreased within 300 fs after the 430 nm pulse pumping and then slowly decreased to zero, while the absorbance change at the 350 nm probe had a positive constant component in the over one picosecond time region. The RE analysis showed that this constant component is due to the yielded trans molecules, and its positive value is due to the fact that the absorption cross-section of the -to- transition in their trans molecules is larger than that of the -to- transition in the original cis molecules. 相似文献
154.
S. R. John S. C. Langford J. T. Dickinson 《Applied Physics A: Materials Science & Processing》2008,92(4):981-985
We report time- and mass-resolved measurements on neutral particles emitted from polytetrafluoroethylene (PTFE) during exposure
to 157-nm laser radiation at fluences where etching is observed. By comparing the time-of-flight signals over a range of masses,
we conclude that (CF2)
N
fragments for N=1–6 are emitted directly from the surface in substantial quantities. In contrast, the monomer (N=2) is the principal product during irradiation at 248 nm, where thermal decomposition is important. The time-of-flight signals
of all the (CF2)
N
fragments show fast components with kinetic energies on the order of an electron volt. These high kinetic energies are consistent
with photochemical scission of the polymer backbone, where a fraction of the excitation energy is delivered to the fragment
as kinetic energy. Although clean etching is observed under these conditions, the great majority of the mass removed from
the target appears as much larger fragments that do not reach our detector. The nature of this material and its affect on
the velocity distribution of the observed (CF2)
N
fragments is discussed. 相似文献
155.
Shunsuke Suzuki Akira Nakajima Kouichi Tanaka Ayako Hashimoto Yoshikazu Kameshima Kiyoshi Okada 《Applied Surface Science》2008,254(6):1797-1805
We prepared line-patterned hydrophobic surfaces using fluoroalkylsilane (FAS) and octadecyltrimethoxysilane (ODS) then investigated the effect of line direction on sliding behavior of water droplets by direct observation of the actual droplet motion during sliding. Water droplets slide down with a periodic large deformation of the contact line and sliding velocity fluctuation that occurred when they crossed over the 500-μm ODS line regions in FAS regions on a Si surface tilted at 35°. These behaviors are less marked for motion on a 100-μm line surface, or on lines oriented parallel to the slope direction. Smaller droplets slide down with greater displacement in the line direction on 500-μm line patterning when the lines were rotated at 13° in-plane for the slope direction. This sliding behavior depended on the droplet size and rotation angle, and is accountable by the balance between gravitational and retentive forces. 相似文献
156.
We investigated detailed structural properties of GaAs nanostructures formed by a supply of intense As4 flux to Ga droplets. Scanning electron microscopy (SEM) and cross-sectional transmission electron microscopy (TEM) revealed that whisker-like nanostructures had formed on the truncated cone-shaped bases after crystallization. Moreover, electron energy loss spectroscopy in scanning transmission electron microscopy (STEM-EELS) revealed that elemental Ga atoms remained inside the nanostructures while outside, some had crystallized into GaAs. These findings suggest that crystallization started at the edges of the droplets and the GaAs grew upward along the periphery of the droplets until the droplets were completely covered with crystallized GaAs. 相似文献
157.
Based on the Cantor function and phase modulation, a tunable fractal axicon is formed on a liquid crystal on silicon (LCoS) with an improved generating method. It has higher focusing efficiency in higher fractal stage and approaches to 100% theoretically. The on-axis intensity keeps its fractal structure unchanged in operation of fractal stages. The tunability of the axicon is demonstrated by tune fractal stage from 1 to 3 and focal length from 0.8 m to 1 m. We also provide details of theoretical analyses and experimental results. 相似文献
158.
High Speed and Ultra-Low-Power Phase Change Line Cell Memory Based on SiSb Thin Films with Nanoscale Gap of Electrodes Less Than 100nm
下载免费PDF全文
![点击此处可从《中国物理快报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Si16Sbs4-based line cell phase change random access memory (PCRAM), in which the Si16Sbs4 phase change line is contacted by TiN electrodes with a nanoscale gap, is fabricated by electron beam lithography. The lowest current and measured pulse width for RESET operation are 115 μA and 18 ns, respectively. The measured shortest pulse width for recrystallization is 110ns, with applied pulse amplitude of 1.5 V. SET and RESET currents for line cells with different line lengths are determined. Endurance of 106 cycles with a resistance ratio of above 800 has been achieved. 相似文献
159.
We consider the quasi-static energy of a drop on a textured hydrophilic surface, with taking the contact angle hysteresis (CAH) into account. We demonstrate how energy varies as the contact state changes from the Cassie state (in which air is trapped at the drop bottom) to the Wenzel state (in which liquid fills the texture at the drop bottom) assuming that the latter state nucleates from the center of the drop bottom. When the textured substrate is hydrophilic enough to allow spontaneous penetration of liquid film of the texture thickness, the present theory asserts that the drop develops into an experimentally observed state in which a drop looks like an egg fried without flipped over (sunny-side up) with a well-defined radius of "the egg yolk." Otherwise, the final contact state of the drop becomes like a Wenzel state, but with the contact circle smaller than the original Wenzel state due to the CAH. We provide simple analytical estimations for the yolk radius of the "sunny-side-up" state and for the final radius of the contact circle of the pseudo-Wenzel state. 相似文献
160.
A. Stampanoni-Panariello B. Hemmerling W. Hubschmid 《Applied physics. B, Lasers and optics》1998,67(1):125-130
Received: 1 December 1997 / Revised version: 27 January 1998 相似文献