全文获取类型
收费全文 | 62篇 |
免费 | 0篇 |
专业分类
化学 | 12篇 |
力学 | 2篇 |
数学 | 10篇 |
物理学 | 38篇 |
出版年
2021年 | 1篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2008年 | 1篇 |
2007年 | 2篇 |
2006年 | 5篇 |
2005年 | 2篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1971年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有62条查询结果,搜索用时 15 毫秒
41.
Wim Hesselink 《Commentarii Mathematici Helvetici》1979,54(1):105-110
LexX be the closure of aG-orbit in the Lie algebra of a connected reductive groupG. It seems that the varietyX is always normal. After a reduction to nilpotent orbits, this is proved for some special cases. Results on determinantal
schemes are used forGl
n
. IfX is small enough we use a resolution and Bott's theorem on the cohomology of homogeneous vector bundles. Our results are conclusive
for groups of typeA
1,A
2,A
3 andB
2. 相似文献
42.
43.
We describe laser ablation of Si under water by 5 ns, 355 nm and 100 fs, 800 nm pulses. Compared to that in air, an approximately twofold improvement in the ablation rate is found in water for femtosecond and nanosecond pulses. For higher laser irradiances, the plasma that forms at the water-air interface hampers further improvement of the ablation rate. We investigated the enhanced ablation process in water and found that the cavity-confinement geometry that increases the laser energy coupling to the target and allows more energy to be transferred to the cavity sidewalls plays an important role in the escalated material removal process. In addition, we show that the water layer that effectively reduces the oxidation and redeposition of the ablated debris is also responsible for improvements in the ablation process. 相似文献
44.
We demonstrate a novel apodization technique for holographic data storage using two-photon recording in stoichiometric lithium niobate. The gating light-intensity profile is used to achieve grating apodization inside the bulk of the crystal during recording in the transmission geometry. Experimental Bragg-selectivity curves and theoretical fits indicate a >20-dB drop in multiplexing cross talk. 相似文献
45.
One-color one-beam pumping of Er(3+)-doped ZBLAN glasses for a three-dimensional two-step excitation display 总被引:3,自引:0,他引:3
We demonstrate a one-color one-beam pumping method for a three-dimensional two-step excitation fluorescent display with Er(3+) -doped ZBLAN glass. A localized green fluorescent spot is obtained by use of a focused pump-light beam at 979 nm. The quantum efficiency of the two-step excitation fluorescence is investigated in a time-dependent analysis and an experiment with a pulsed pump light. 相似文献
46.
M. Palacz Z. Sujkowski J. Nyberg J. Bacelar J. Jongman W. Urban W. Hesselink J. Nasser A. Plompen R. Wyss 《Zeitschrift für Physik A Hadrons and Nuclei》1991,338(4):467-468
Gamma ray spectra from the117Sn(18O,4n)131 Ce reaction have been studied with the NORDBALL array of 15 Compton-suppressed Ge detectors. States up to I=51/2 , E8 MeV are populated. Observed bands are interpreted in terms of quasiparticle configurations. 相似文献
47.
Digital holographic storage system incorporating optical fixing 总被引:6,自引:0,他引:6
Digital holograms have been written in stoichiometric Pr:LiNbO(3) in a two-color recording scheme, demonstrating what is to our knowledge the first all-optical nondestructive readout of digital data. Using writing light at 800nm and gating light at 476nm, we stored and retrieved 256-kbit digital data pages with a raw bit-error rate BER of <10(-4) . 相似文献
48.
Polymer films doped with 2-(5, 5-dimethyl-3-styryl-cyclohex-2-enylidene)-malononitrile chromophore and various sensitizers have been prepared and characterized. The material exhibits high sensitivity in the red region (S=0.26 cm(2)/J at lambda=633 nm), a large dynamic range (Dn=-0.05) , and large transient two-beam coupling gain (G=110 cm(-1)) . Self-diffraction effects, such as energy and phase coupling, and photoinduced scattering are studied. 相似文献
49.
D. G. Middleton J. R. M. Annand C. Barbieri P. Barneo H. P. Blok R. Böhm M. O. Distler J. Friedrich C. Giusti D. I. Glazier P. Grabmayr T. Hehl J. Heim W. H. A. Hesselink E. Jans M. Kohl L. Lapikás I. J. D. MacGregor I. Martin J. C. McGeorge H. Merkel F. Moschini G. Rosner M. Seimetz H. de Vries Th. Walcher D. P. Watts B. Zihlmann 《The European Physical Journal A - Hadrons and Nuclei》2006,29(3):261-270
This paper reports on the first measurement of the 16O(e, e'pn)14N reaction. Data were measured in kinematics centred on a super-parallel geometry at energy and momentum transfers of 215MeV
and 316MeV/c. The experimental resolution was sufficient to distinguish groups of states in the residual nucleus but not good enough to
separate individual states. The data show a strong dependence on missing momentum and this dependence appears to be different
for two groups of states in the residual nucleus. Theoretical calculations of the reaction using the Pavia code do not reproduce
the shape or the magnitude of the data.
An erratum to this article is available at. 相似文献
50.
Punnag Padhy Mohammad Asif Zaman Michael Anthony Jensen Lambertus Hesselink 《Electrophoresis》2021,42(9-10):1079-1092
Electrically polarizable micro- and nanoparticles and droplets can be trapped using the gradient electric field of electrodes. But the spatial profile of the resultant dielectrophoretic force is fixed once the electrode structure is defined. To change the force profile, entire complex lab-on-a-chip systems must be re-fabricated with modified electrode structures. To overcome this problem, we propose an approach for the dynamic control of the spatial profile of the dielectrophoretic force by interfacing the trap electrodes with a resistor and an inductor to form a resonant resistor–inductor–capacitor (RLC) circuit. Using a dielectrophoretically trapped water droplet suspended in silicone oil, we show that the resonator amplitude, detuning, and linewidth can be continuously varied by changing the supply voltage, supply frequency, and the circuit resistance to obtain the desired trap depth, range, and stiffness. We show that by proper tuning of the resonator, the trap range can be extended without increasing the supply voltage, thus preventing sensitive samples from exposure to high electric fields at the stable trapping position. Such unprecedented dynamic control of dielectrophoretic forces opens avenues for the tunable active manipulation of sensitive biological and biochemical specimen in droplet microfluidic devices used for single-cell and biochemical reaction analysis. 相似文献