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1.
Solid-solution formation in binary aluminium-based alloys is due essentially to the combined effects of the size and valence of solvent and solute atoms, as expected by the four Hume-Rothery rules. The lattice parameter of aluminium in the solid solution of the sputtered Al?Fe films is [Al-a (Å)=4.052?6.6×10?3Y]. The increasing and decreasing evolution of the lattice parameter of copper [Cu-a (Å)=3.612+1.8×10?3Z] and aluminium [Al-a (Å)=4.048?1.6×10?3X] in the sputtered Al-1.8 to 92.5 at. % Cu films is a result of the difference in size between the aluminium and copper atoms. The low solubility of copper in aluminium (<1.8 at % Cu) is due to the valences of solvent and solute atoms in contrast with other sputtered films prepared under similar conditions, such as Al?Mg (20 at. % Mg), Al?Ti (27 at. % Ti), Al?Cr (5at. % Cr) and Al?Fe (5.5 at. % Fe) where the solubility is due to the difference in size. 相似文献
2.
V. G. Arkhipkin A. K. Popov V. P. Timofeev 《Applied Physics A: Materials Science & Processing》1978,16(2):209-210
Upconversion of low-level ir radiation at 3.39 μm to the near ultraviolet at 330.5 nm has been obtained using the resonantly
enhanced third-order nonlinearity of Na atoms. This enhancement has been achieved by two-photon resonant pumping of the nonallowed
Na 3s–5s transition with a dye-laser radiation at 602.4 nm. Self-phase-matching has been observed. 相似文献
3.
A. I. Harris J. Stutzki U. U. Graf R. Genzel 《International Journal of Infrared and Millimeter Waves》1989,10(11):1371-1376
We accurately measured the noise temperature and conversion loss of a cryogenically cooled Schottky diode operating near 800 GHz, using the UCB/MPE Submillimeter Receiver at the James Clerk Maxwell Telescope. The receiver temperature was in the range of the best we now routinely measure, 3150 K (DSB). Without correcting for optical loss or IF mismatch, the raw measurements set upper limits ofT
M=2850 K andL
M=9.1 dB (DSB), constant over at least a 1 GHz IF band centered at 6.4 GHz with an LO frequency of 803 GHz. Correction for estimated optical coupling and mismatch effects yieldsT
M=1600 K andL
M=5.5 dB (DSB) for the mixer diode itself. These values indicate that our receiver noise temperature is dominated by the corner cube antenna's optical efficiency and by mixer noise, but not by conversion loss or IF mismatch. The small fractional IF bandwidth, measured mixer IF band flatness from 2 to 8 GHz, and similarly good receiver temperatures at other IF frequencies imply that these values are representative over a range of frequencies near 800 GHz. 相似文献
4.
J. Schneider 《International Journal of Infrared and Millimeter Waves》1995,16(1):75-82
Superfluorescence has been demonstrated for the first time at 3.9m in holmium-doped fluoride glass optical fiber. Fluorescence measurements were possible at room temperature while pumping around 650 nm. Cooled to 173 K superfluorescence was obtained. 相似文献
5.
Timo J. Tolmunen Antti V. R?is?nen 《International Journal of Infrared and Millimeter Waves》1989,10(4):475-504
In this research the efficiency of a millimeter-wave Schottky-varactor quadrupler was studied. Theoretical simulations were carried out by using a nonlinear analysis program to find the optimum embedding impedances for a given diode. Emphasis was placed on the study of optimum idlers at the 2nd and 3rd harmonics, which are essential for a high quadrupling efficiency. For experimental verification a quadrupler for 140–155 GHz output frequency range with fixed idler terminations was constructed. This quadrupler was tested with different output configurations. A 10% tunable bandwidth was obtained with output power in the range of 1.5–2.7 mW whenP
in
=40 mW. The highest efficiency measured was 11.3% at 148 GHz with 10 mW input power. 相似文献
6.
Interchromophore interactions and energy transfer in covalently bound porphyrin-chlorine heterodimer
V. N. Knyukshto É. I. Zen’kevich V. A. Kuz’mitskii V. I. Gael’ A. M. Shul’ga E. G. Levinson A. F. Mironov 《Journal of Applied Spectroscopy》1998,65(1):75-83
Energetis of interchromophore interactions in a covalently bound prophyrin-chlorine heterodimer (Por-O-Chl) is investigated
at temperatures from 77 to 293 K in solvents with differing polarity (toluene, tetrahydrofurane, and diethyl ether: petroleum
ester: isopropanole=5∶5∶2 mixture). We substantiate the conclusion that the strong quenching of fluoresence and phosphorescence
of the porphyrin fragments in both stable isomers of the Por-O-Chl heterodimer is induced not by the photoinduced charge transfer
but rather by efficient processes of singlet-singlet (probability FSS=1.3·1011 to 6.8°1010 sec−1) and triplet-triplet (probability FTT≥108 sec−1) radiationless electronic excitation transfer. It is shown that the S−S transfer takes place without quantum losses from
the thermodynamically equilibrated S1 state of the donor, and its dynamics and main regularities at temperatures from 77 to 293 K are described by the inductive
resonance theory without any additional asssumptions.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 1, pp. 75–82, January–February, 1998. 相似文献
7.
Timo J. Tolmunen Antti V. Räisänen 《International Journal of Infrared and Millimeter Waves》1989,10(4):505-518
The multiplication efficiency of a millimeter-wave Schottky-varactor quintupler with fixed idler terminations was studied. The highest efficiency measured was 4.2% at 168 GHz with 10 mW input power and 3.3% with 40 mW input power. Over the range from 165 GHz to 170 GHz the output power was 0.7–1.3 mW withp
in
=40 mW. 相似文献
8.
Conclusion The specialized measuring setup described in the paper makes it possible to measure correctly and with reasonably high accuracy
the luminescence decay kinetics of dyes within the time range from 40 psec to 5 nsec upon excitation in the visible range
and at 1.064 μm.
The system is highly flexible, having at the same time reasonably large data storage memory, and is completely automated.
Such a system, undoubtedly, will be helpful for researchers working in the field of physics of laser media and dyes—passive
modulators for femtosecond laser systems.
The authors are grateful to M. V. Bondar for fruitful discussions and for help with the experiments.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 1, pp. 128–134, January–February, 1995. 相似文献
9.
电子原子散射中的S,T,U参数可用来描述散射前后自旋状态的变化,研究精细结构水平上的散射激发振幅之间的关系,进而揭示电子原子碰撞过程中电子自旋-轨道耦合以及电子-电子交换等自旋相关效应.采用扭曲波玻恩近似计算了钠原子受电子散射S→P跃迁中的S,T,U参数,分析了多种入射能(2.2—60 eV)的电子与钠原子激发S→P跃迁过程的S,T,U参数随散射角的分布,其中对10 eV入射能的Sp参数与已报道实验数据符合一致.结果表明,较低能电子入射下的S,T,U参数随散射角的分布幅度和起伏都比较明显,入射能大于40 eV的电子入射,S,T,U参数的散射角分布变化很小.
关键词:
散射激发
S')" href="#">S
T')" href="#">T
U参数')" href="#">U参数
散射振幅
自旋相关效应 相似文献
10.
Liudvikas Pranevičius Darius Milčius Liudas Pranevičius Vaiva Širvinskaitë Jurgita Nomgaudyte Jean-Paul Rivier Claude Templier 《Central European Journal of Physics》2004,2(1):67-89
This paper presents a generalized approach to the mechanisms of oxidation, hydrogenation and nitriding of metals under ion
irradiation with reactive particles at elevated temperatures. Experimental results on the plasma oxidation of bilayered Y/Zr
films, the plasma hydrogenation of Mg films and the ion beam (1.2 keV N
2
+
) nitriding of stainless steel are presented and discussed. We make special emphasis on the analysis of surface effects and
their role in the initiation of mixing of bilayered films, the ingress of reactive species in the bulk and the restructuring
of the surface layers. It is suggested that primary processes driving reactive atoms from the surface into the bulk are surface
instabilities induced by thermal and ballistic surface atom relocations under reactive adsorption and ion irradiation, respectively.
The diffusion of adatoms and vacancies, at temperature when they become mobile, provide the means to relax the surface energy.
It is recognized that the stabilizing effect of surface adatom diffusion is significant at temperatures below 300–350°C. As
the temperature increases, the role of surface adatom diffusion decreases and processes in the bulk become dominant. The atoms
of subsurface monolayers occupy energetically favorable sites on the surface, and result in reduced surface energy. 相似文献
11.
Karen B. Paul 《Central European Journal of Physics》2005,3(1):115-126
A monocrystal ofFe
3
O
4 is characterized by resistance, magnetoresistance and magnetic measurements in a temperature range from 4.2 K to 350 K and
magnetic field-cycling from −9 T to 9 T. The resistance measurements revealed a metal-insulator Verwey transition (VT) atT
v
=123.76 K with activation energy E=92.5 meV at T >T
v
and temperature-substitute for the activation energy below the VT,T
0=E/k
B
≈3800 K within 70 K–110K. The magnetotransport results independently verified the VT at 123.70 K, with discontinuous change
in the magnetic moment ΔM≈0.21 ΔM≈0.21μ
B
and resistance hysteresis, dependent on the magnetic field in a narrow temperature range of 0.4° around theT
v
. The magnetic characterization established self consistentlyT
v
as ≈123.67 K, the jump in the magnetization at the VT≈0.25μ
B
and confirmed, that the magnetocrystalline anisotropy is the main microscopic mechanism responsible for the magnetization
of the monocrystal (88%) with additional natural and imposed defects contributing as 12%. 相似文献
12.
S. S. Andreev A. D. Akhsakhalyan M. A. Bibishkin N. I. Chkhalo S. V. Gaponov S. A. Gusev E. B. Kluenkov K. A. Prokhorov N. N. Salashchenko F. Schafers S. Yu. Zuev 《Central European Journal of Physics》2003,1(1):191-209
We present research investigations in the field of multilayer optics in X-ray and extreme ultra-violet ranges (XUV), aimed
at the development of optical elements for applications in experiments in physics and in scientific instrumentation. We discuss
normal incidence multilayer optics in the spectral region of “water window”, multilayer optics for collimation and focusing
of hard X-ray, multilayer dispersing elements for X-ray spectroscopy of high-temperature plasma, multilayer dispersing elements
for analysis of low Z-elements. Our research pays special attention to optimization of multilayer optics for projection EUV-lithography
(ψ-13nm) and short period multilayer optics. 相似文献
13.
A. N. Yakunin 《Central European Journal of Physics》2003,1(2):355-362
Based on a solution of the polymer excluded volume problem, a technique is proposed to estimate some parameters at the isotropic-nematic
liquid crystal phase transition (the product of the volume fraction of hard sticks and the ratio of the stick length, L, to its diameter, D; the maximum value of this ratio at which one cannot regard the stick as hard). The critical exponents are estimated. The
transition of a swelling polymer coil to ideal is revealed as the polymerization degree of a macromolecule increases. The
entanglement concentration obtained agrees with experimental data for polymers with flexible chains. The number of monomers
between neighbor entanglements is assumed to be the ratio L/D. A comparison of the theory with other ones and recent experimental data is made. 相似文献
14.
B. M. Dzhagarov N. N. Kruk N. V. Konovalova A. A. Solodunov I. I. Stepuro 《Journal of Applied Spectroscopy》1995,62(2):285-289
Presented at the XV IUPAC Symposium on Photochemistry, Prague, July 17–22, 1994. 相似文献
15.
Scientific-Research Institute of Mechanics and Physics at the Saratov State University, 112-A, Bolshaya Kozach'ya Str., Saratov,
410071, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 3, pp. 235–238, May–June, 1995. 相似文献
16.
In this work we investigate the single- and the double-spin asymmetries at the collisions of polarized protons pp → (γ
*, Z
0, Z′) + X within the scope of QCD, the electroweak interaction and superstring E
6 theory. The helicity amplitude method is used. Analytical expressions for the single- and the double-spin asymmetries are
obtained and their dependence on the transverse momentum of the lepton pair is investigated at the three different values
of invariant masses of the lepton pair. The pure contribution coming from the superstring Z′ boson on the single- and double- spin asymmetries has been extracted. The results obtained allow investigation of the spin
structure of the proton. 相似文献
17.
S. R. Davies C. T. Cunningham L. T. Little D. N. Matheson 《International Journal of Infrared and Millimeter Waves》1992,13(5):647-658
We describe the design and performance of a 210–280 GHz SIS heterodyne receiver built for use on the Maxwell Telescope. The mixer utilises a lead alloy SIS tunnel junction, mounted in 41 reduced height rectangular waveguide, and is tuned with a backshort in 21 reduced height guide. The receiver has a receiver noise temperature of <200K (DSB) across the RF band from 210–270 GHz, with a best noise temperature measured in the laboratory of 113K (DSB) at 231 GHz. A prototype version of this receiver was successfully operated on the telescope in May 1989. By direct intercalibration with a Schottky diode receiver we deduced a best receiver noise temperature of 140K (DSB) at 245 GHz. Discrepancies between this figure and that derived from broad band thermal load calibration are discussed in the accompanying paper (Little et al., 1992, this issue). 相似文献
18.
以单质硼和高纯石墨的混合粉末压制成型的靶材作为靶源,采用过滤阴极真空电弧技术制备不同硼含量的掺硼四面体非晶碳膜.分别采用四探针法、阻抗分析仪和电化学界面对薄膜的变温电导率、I-V特性和C-V特性进行了测试和研究.实验结果表明,当B含量由0增加至6.04 at%时,薄膜的室温电导率先逐渐增大而后逐渐减小,相应薄膜的电导激活能先逐渐减小而后逐渐增大,并在2.13 at%时分别出现最大和最小值1.42×10-7S/cm和0.1eV.此外,掺硼四面体非晶碳/n型硅异质结的I-V曲线表现出典型的整流特性,表明p-n结二极管已经形成,且结两端的掺杂能级在空间上连续统一.
关键词:
四面体非晶碳
电导率
I-V曲线')" href="#">I-V曲线
C-V曲线')" href="#">C-V曲线 相似文献
19.
Mircho Georgiev Nikolay Goutev Zhorro S. Nickolov Georgi Georgiev 《Central European Journal of Physics》2005,3(1):104-114
Excess thermodynamic functions of D2O water have been calculated from the vibrationally decoupled O−D stretching spectra of very dilute solutions of HOD in H2O. Comparison of the results with reference calorimetric data for water showed a good correspondence for excess heat capacity
above the melting point of ice. The excess enthalpy at the melting point also coincides well with latent heat of melting. 相似文献
20.
Anton A. Akhsakhalyan Aram D. Akhsakhlyan Alexander I. Kharitonov Eugenie B. Kluenkov Vladimir A. Murav’ev Nikolay N. Salashchenko 《Central European Journal of Physics》2005,3(2):163-177
This paper is an overview of the research activities carried out in the past five years at the Institute for Physics of Microstructures
RAS and “X-ray” Company towards the manufacture of multilayer mirror systems capable of forming X-ray beams in the subnanometer
range of wavelengths. The systems fabrication technology is presented, including techniques for producing supersmooth surfaces
of specified shape, methods of graded multilayer structure deposition on such surfaces, and the principles of designing optimal
mirror parameters. The characteristics of a quadrelliptical reflector—a novel high light-gathering power four-corner focusing
system—are reported. 相似文献