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41.
R. Wolleschensky T. Feurer R. Sauerbrey U. Simon 《Applied physics. B, Lasers and optics》1998,67(1):87-94
Received: 26 August 1997/Revised version: 2 February 1998 相似文献
42.
Received: 16 March 1996 相似文献
43.
China, as one of the members of ITER (international thermonuclear experimental reactor) project, one of the most important construction tasks is the fabrication of the first wall panel and shield blankets, which is the key engineering technology of ITER construction and might be one of the crucial issues of the future reactor too. Since 2004, an associated research team including Southwestern Institute of Physics ( SWIP ), Ninxia Non-ferrous Metal Co. Itd and Chinese Institute of Engineering Physics, as well as Nuclear Power Institute of China has been established. Up to now, several series of interlayer for hot isostatic press ( HIP ) connection of beryllium and CuCrZr alloy have been tested. They are titanium film or coating, Cu coating and Al or AISiMg alloy etc. The bonding strength (tensile or shear strength ) of HIPed Be/Cu joints is up to 100 MPa. 相似文献
44.
M. L. Silva D. M. Sonnenfroh D. I. Rosen M. G. Allen A. O’ Keefe 《Applied physics. B, Lasers and optics》2005,81(5):705-710
A cavity-enhanced spectrometer is developed for detection of exhaled nitric oxide in human breath. A thermoelectrically cooled, pulsed, quantum cascade laser, coupled to a high-finesse cavity, is used for trace-gas measurements. The trace-gas analyzer operates at 5.2 microns and utilizes integrated cavity output spectroscopy. Effective optical path lengths of 1.5 km are achieved in a 50-cm-length cell with a sample volume of 60 mL. The instrument is also capable of simultaneously measuringCO2 concentration in exhaled breath. Measurements were performed on human breath samples as well as simulated breath samples. Here we report a detection limit of ≤ 1 ppbv in 4 s for NO in human breath samples. 相似文献
45.
We applied optogalvanic spectroscopy to observe Zeeman effect in the evanescent wave in Ar gas with the help of a single-mode diode laser. The use of an homogenous external magnetic field enabled us to observe different π and σ Zeeman split lines contribution. We studied two orthogonal directions of external magnetic field and two orthogonal polarizations of the incident wave with respect to the plane of incidence. The analysis of relative line strengths leads to the determination of the polarization state of the evanescent wave. 相似文献
46.
Deformed Hartree-Fock calculations are performed for some light nuclei in a large configuration space consisting of first
four major shells. The interaction employed is the modified Skyrme interaction in which the deformed density is replaced by
the band averaged scalar density that makes the Hamiltonian rotationally invariant rendering the spectroscopic calculations
feasible. It is shown that the introduction of density dependence spreads out the energy spectra and that the Skyrme variant
SIV which has a weak density dependence gives best overall agreement for energy spectra and the available data for the electromagnetic
properties of the nuclei studied. It is found that the maximum contribution to the energy of any state in the low lying spectrum
comes from thes-state attractive ands-state repulsive parts of the Skyrme interaction. It is also shown that when two-body density dependent version of Skyrme
interaction is used, the Koopmans theorem no longer holds. 相似文献
47.
In his recent paper, Shear modulus collapse of lattices at high pressure, J. Phys. Cond. Matt. 16 (2004) L125, V.V. Kechin claims that the zero temperature shear modulus of a metallic solid vanishes at a high critical pressure, and the critical pressures for this shear modulus collapse lie in the range 0-250 Mbar for elemental metals. Here we demonstrate that Kechin's arguments contain an erroneous assumption, and therefore, do not prove that all metals become mechanically unstable at high pressures. Ab initio calculations and experimental results on a number of solids are analyzed to confirm our conclusion. 相似文献
48.
The electronic, magnetic, and bonding properties of the Cr2TiX (X=Al, Ga, Si, Ge, Sn, Sb) Heusler alloys have been investigated using first-principles calculations. The results show that Cr2TiSb exhibits a half-metallic nature and Cr2TiGa and Cr2TiSn exhibit a nearly half-metallic nature. From analysis of the density of states and the electron density difference along the Ga→Sn→Sb series for sp atoms, we found that the Cr-Ti bond demonstrates covalent character with more or less the ionic and metallic nature. In addition, the Cr-Ti bonding strength increases along this series. All the compounds have a negative total magnetic moment, most of which are confined to the Cr atoms. There exists a 1.0μB increasing trend of the total moment along the III→IV→V main group for sp atoms, and only the total moment of Cr2TiSb coincides well with the Slater-Pauling behavior. 相似文献
49.
A facile, low-temperature, and low-cost chemical route has been developed to prepare ZnO nanowire and nanosphere compound structures. The morphology, structure, and composition of the yielded products have been examined by field-emission scanning electron microscopy, transmission electron microscopy, and X-ray diffraction measurements. We have systematically investigated the optical properties of the ZnO nanostructures by micro-Raman, photoluminescence, and transmission spectroscopy. The results demonstrate that the yielded ZnO nanostructures possess good optical quality with high light absorption. We have further successfully employed the obtained ZnO compound nanostructures in dye-sensitized solar cells. The light-to-electricity conversion results show that the compound nanostructure exhibits a significant enhancement of short-circuit current density due to the increased surface area and light scattering in the compound nanostructures. The present chemical route provides a simple way to synthesize various compound nanostructures with high surface area for nanodevice applications. 相似文献
50.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献