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971.
利用激光并采用热释电探测器实时测量比辐射率及温度的系统 总被引:4,自引:2,他引:4
设计了一种利用半导体激光器InGaAs/I作为光源 ,采用钽酸锂热释电探测器作为光接收元件 ,以 80 31单片机为核心的中、高温物体比辐射率及温度的实时测量系统。该系统主要由光学发射与接收系统、信号放大与处理系统和显示系统三部分组成。文中还介绍了该系统的基本原理及结构 ,分析了其中的技术难点及其解决方法 ,讨论了系统的灵敏度、比辐射率与温度的测量精度。分析表明 :对 42 7℃的抛光钢铸件而言 ,系统的最小鉴别温差为 0 32K ,比辐射率的测量精度σελ=6 5× 10 -3 ,|σελ/ελ|=1 2 0 % ;温度的测量精度σT =1 0 6K ,|σT/T|=0 15 2 %。 相似文献
972.
Stohlker T Mokler PH Bosch F Dunford RW Franzke F Klepper O Kozhuharov C Ludziejewski T Nolden F Reich H Rymuza P Stachura Z Steck M Swiat P Warczak A 《Physical review letters》2000,85(15):3109-3112
The Lyman- alpha transitions of hydrogenlike uranium associated with electron capture were measured in collisions of stored bare U (92+) ions with gaseous targets at the storage ring ESR. By applying the deceleration technique, the experiment was performed at slow collision energies in order to reduce the uncertainties associated with Doppler corrections. From the measured centroid energies, a ground state Lamb shift of 468 eV+/-13 eV is deduced which gives the most precise test of quantum electrodynamics for a single electron system in the strong field regime. In particular, the technique applied paves the way towards the 1 eV precision regime. 相似文献
973.
Ni0.5Zn0.5Fe2O4–forsterite composites were synthesized by a sol–gel method. X-ray diffraction and SEM were used to characterize the crystallization behavior of the composite samples which were heat treated at temperatures varying from 800 to 1100°C. The results showed that Ni0.5Zn0.5Fe2O4 and forsterite (Mg2SiO4) can co-crystallize and the crystallites grow even more larger with increasing heat-treatment temperature. High-frequency (10 MHz–1 GHz) magnetic and dielectric properties of the composite samples were presented. Permeability increased with heat-treatment temperature. Quality factor was found to be two orders higher than that of equivalent pure, bulk ferrite. 相似文献
974.
CEL溶液中二磺酸基二邻苯二甲酰亚胺甲基酞菁锌的电子吸收和荧光光谱 总被引:1,自引:0,他引:1
两亲性金属酞菁配合物二磺酸基二邻苯二甲酰亚胺甲基酞菁锌(ZnPcS2P2)能有效选择地滞留在组织中,是一种新型的光动力治疗肿瘤的光敏剂。有关酞菁化合物治疗肿瘤的机制目前还不清楚,而对CEL溶液中该光敏剂状态的研究对阐明其机制有重要意义,本文对不同浓度CEL溶液中的二磺酸基二邻苯二甲酰胺甲基酞菁锌的吸收光谱和荧光光谱进行了研究,探讨了它在溶液中的聚集状态,通过分析确定其聚集态为二聚体,并获得其平衡常数和单体的摩尔吸光系数。 相似文献
975.
Using a microwave cavity perturbation technique, we have succeeded in observing cyclotron resonances in the layered Perovskite superconductor Sr2RuO4. Three cyclotron masses are deduced, corresponding to mcγ=9.7me, mcβ=5.8me and mc=4.3 me. A comparison between these values and the effective masses deduced from other techniques provides us with a unique means of gauging the role of Coulomb correlations in the title compound. 相似文献
976.
S. N. Andrianov A. B. Balakin R. A. Daishev G. V. Kisun’ko Z. G. Murzakhanov A. F. Skochilov 《Technical Physics》2000,45(4):453-457
It is shown that stabilization of the different frequency of optical radiations generated in the reference and signal resonators of the Dulkyn laser-interferometric gravitational-wave detector results in an efficient reevaluation of basic parameters describing the line widths of the laser radiation and the passive resonator, as well as the minimal laser power required to separate the valid signal from noises caused by natural fluctuations. 相似文献
977.
M.B. Zölfl Th. Maier Th. Pruschke J. Keller 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,13(1):47-53
We study one-particle spectra and the electronic band-structure of a CuO
2
-plane within the three-band Hubbard model. The Dynamical Mean-Field Theory (DMFT) is used to solve the many particle problem.
The calculations show that the optical gap is given by excitations from the lower Hubbard band into the so called Zhang-Rice singlet band. The optical gap turns out to be considerably smaller than the bare charge transfer energy () for a typical set of parameters, which is in agreement with experiment. We also investigate the dependence of the shape
of the Fermi surface on the different hopping parameters t
CuO and t
OO. A value t
OO
/
t
CuO
>0 leads to a Fermi surface surrounding the M point.
Received 21 September 1998 and Received in final form 8 June 1999 相似文献
978.
Formation and crystal structure of metallic inclusions in a HPHT as-grown diamond single crystal 总被引:2,自引:0,他引:2
L.-W. Yin N.-W. Wang Z.-D. Zou M.-S. Li D.-S. Sun P.-Z. Zheng Z.-Y. Yao 《Applied Physics A: Materials Science & Processing》2000,71(4):473-476
One of the most important characteristics associated with crystal growth technology is the entrapment of inclusions by the
growing crystal. Diamond single crystals prepared under high temperature-high pressure (HPHT) usually contain metallic inclusions.
In the present paper, metallic inclusions in a diamond grown from a Fe-Ni-C system using the HPHT method have been, for the
first time, systematically examined by transmission electron microscopy (TEM). Energy dispersive X-ray spectrometry (EDS)
, combined with selected area electron diffraction (SAD) patterns, has been used to identify the chemical composition and
crystal structure of the metallic inclusions. The metallic inclusions were found to be composed mainly of cubic γ-(FeNi),
face-centered cubic (FeNi)23C6, ortho-rhombic Fe3C and hexagonal Ni3C, which may have been formed through the entrapment of molten catalyst by the growth front or through reaction of the trapped
melt with contaminants in the diamond.
Received: 19 June 2000 / Accepted: 21 June 2000 / Published online: 16 August 2000 相似文献
979.
J. Hüfner Y.B. He B.Z. Kopeliovich 《The European Physical Journal A - Hadrons and Nuclei》2000,7(2):239-244
Prompt gluons are an additional source for charmonium suppression in nuclear collisions, in particular for nucleus-nucleus
collisions. These gluons are radiated as bremsstrahlung in N-N collisions and interact inelastically with the charmonium states
while the nuclei still overlap. The spectra and mean number <n
g> of the prompt gluons are calculated perturbatively and the inelastic cross section σabs
Ψg is estimated. The integrated cross sections σ(A B →J/ψX) for p-A and A-B collisions and the dependence on transverse energy for S-U and Pb-Pb can be described quantitatively with
some adjustment of one parameter <n
g>σabs
Ψg.
Received: 20 August 1999 相似文献
980.