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81.
Thermal conduction modes in a nanocolloid (nanofluid) are quantitatively assessed by combining linear response theory with molecular dynamics simulations. The microscopic heat flux is decomposed into three additive fluctuation modes, namely, kinetic, potential, and collision. For low volume fractions (<1%) of nanosized platinum clusters which interact strongly with xenon host liquid, a significant thermal conductivity enhancement results from the self correlation in the potential flux. Our findings reveal a molecular-level mechanism for enhanced thermal conductivity in nanocolloids with short-ranged attraction and offer predictions that can be experimentally tested. 相似文献
82.
We investigate a flexibly tunable multiwavelength semiconductor-optical-amplifier-based fiber ring laser with continuous wavelength spacing controllability incorporating a superimposed chirped fiber Bragg grating (CFBG). The wavelength spacing of a superimposed CFBG can be continuously controlled by symmetrically modifying the chirp bandwidth of the grating with the specially designed apparatus. We achieve a wide and continuous tuning range of the wavelength spacing from 0.35 to 0.78 nm. The continuous tunability of the wavelength spacing is measured to be ~ +/-0.033 nm/mm. By controlling the reflection bandwidth of the tunable CFBG, we can independently adjust the number of lasing channels from 2 to 23 at the wavelength spacing of 0.51 nm. 相似文献
83.
84.
Hye Young Kwon Jun Taek Woo Dea Uk Lee Tae Whan Kim Young Ju Park 《Solid State Communications》2009,149(1-2):52-55
Strained potential profiles and electronic subband energies of InAs/GaAs coupled double quantum dots (DQDs) were calculated by using a three-dimensional finite-difference method (FDM) taking into account shape-based strain and nonparabolic effects. The interband transition energies from the ground electronic subband to the ground heavy-hole band (E1-HH1) in the InAs/GaAs DQDs, as determined from the FDM calculations taking into account strain and nonparabolic effects, were in reasonable agreement with the experimental peaks corresponding to the (E1-HH1) interband transition energies at several temperatures, as determined from the temperature-dependent photoluminescence spectra. 相似文献
85.
The creep motion in a two-dimensional fully frustrated square lattice Coulomb gas model with disorders is studied by using the Monte Carlo technique. The dependence of charge current density J on electric field E is investigated at low temperature T and at low E. The results show that the creep obeys the Arrhenius law J - C(T) exp[-U(E)/T]. The prefactor C(T) increases with the temperature in a power law relation with an exponent about 3.0. The energy barrier U ( E) increases logarithmically with Ec,/ E as U ( E) - Uo ln( Ec/ E) with Ec being the critical field at zero temperature. 相似文献
86.
Kim Sang Woong Hong Chang Yong Koh Jong Sung Lee Eun Ju Lee Koo 《Molecular diversity》1997,3(2):133-136
Using solid phase synthesis, a library has been constructed of benzamidine-derived sulfonamides which have strong inhibitory
activity against blood coagulant thrombin. The library compounds were obtained in good yield and high purity.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
87.
B. Q. Yao X. L. Liu B. S. Chen L. X. Yu X. H. Sun Z. Y. Chen Y. L. Ju Y. Z. Wang 《Laser Physics》2012,22(3):544-546
A resonantly pumped Q-switched Er:YAG laser at 1645 nm was reported. 1 mJ of output pulse energy was achieved for Q-switched
operation at 100 Hz repetition rate under total incident pump power of 4 W. An output peak power of 14 kW and pulse width
of 60.6 ns were obtained. 相似文献
88.
We demonstrated continuous-wave (CW) and Q-switched operation of a room-temperature Ho:YAP ring laser that is resonantly end-pumped by a diode-pumped Tm:YLF laser at 1.91 ??m. Continuous wave output power of 3 W at 2119 nm is obtained under the absorbed pump power of 10.17 W, corresponding to a slope efficiency of 60%. For the Q-switched regime the maximum pulse energy of 1.58 mJ and the minimum pulse width of 590 ns at the repetition rate of 1 kHz are achieved. 相似文献
89.
A periodically poled lithium niobate (PPLN) optical parametric generator (OPG) pumped by a laser diode (LD)-pumped Q-switched Tm,Ho:GdVO4 laser operated at 2.048 μm with pump pulse of 25 ns and repetition rate of 10 kHz is reported. 相似文献
90.
In Hee Shin Seongmin Ju Suhas Poyyil Veetil Won-Taek Han Dug Young Kim 《Optics Communications》2008,281(9):2504-2508
We have measured residual stress in a commercial single mode optical fiber and observed its relaxation in an annealing process with a polariscopic stress measurement method. After annealing the fiber for an hour at various high temperatures in a specially made image furnace we have measured the temperature dependent relaxation of frozen-in viscoelastic stress in the fiber. We have proposed a simple physical model to explain recently observed relaxation of frozen-in viscoelastic stress in optical fibers based on the Kelvin-Voigt model of viscoelastic materials. The experimental results are explained with our model of frozen-in viscoelastic stress by introducing simplified four-step procedures for fiber drawing. 相似文献