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41.
In this paper, we describe an aircraft loading problem submitted by the French military agency (DGA) as part of a more general military airlift planning problem. It can be viewed as a kind of bi-dimensional bin-packing problem, with heterogeneous bins and several additional constraints. We introduce two-phase methods for solving this NP-hard problem. The first phase consists in building good initial solutions, thanks to two fast algorithms: a list-based heuristic and a loading pattern generation method. Both algorithms call a constraint-based subroutine, able to determine quickly if the items already loaded can be reshuffled to accommodate a new object. The second phase improves these preliminary solutions using local search techniques. Results obtained on real data sets are presented.  相似文献   
42.
胡逸群  费跃平 《光学学报》1994,14(6):26-631
讨论了横向位移双曝光散斑图维纳谱的信息分布,并由此导出杨氏纹图的一般表达式。讨论了条纹可见度与应变,面内转动,照明光束直径与条纹图图空间坐标的关系,指出了在条纹可见度影响下最大可见条纹数目。还讨论了散斑衬比与衍射晕的关系。  相似文献   
43.
 本文用超声相比较方法测定了高Tc超导体La1.85Sr0.15CuO4,La2CuO4和YBa2Cu3O7的纵波和横波声速,进而导出了它们的纵向模量、切变模量、杨氏模量、泊松比、德拜温度及定体比热。在La1.85Sr0.15CuO4样品上,还进行了压力实验,发现所有弹性模量都是随压强增加而增加。定体比热cV和泊松比σ在高压下则略有下降。德拜温度是随压强增加而增加的。  相似文献   
44.
王凯  古英  龚旗煌 《中国物理》2007,16(1):130-136
Absorption and refraction of the inner transition F2\leftrightarrow F3 of the closed four level N-type atom have been investigated under a weak field. The outer transitions F1\leftrightarrow F3 and F2\leftrightarrow F4 are resonantly interacted with drive field with frequency \omegac and Rabi frequency \Omegac, and saturation field with \Omegas and \Omegas, respectively. For the suitable Rabi frequencies \Omegac and \Omegas, we obtain the Mollow absorption spectrum of probe field. The reason is that the drive field excites the atom to the upper level Fc and simultaneously the saturation field takes the atom out of the lower level F2, leading to the stimulated emission. Meanwhile, due to the dynamic energy splitting induced by the drive and saturation fields, the two- and four-peaked absorption spectra are observed. At the zero off-resonance detuning of probe field, we also find the transfer of dispersion from negative to positive with an increment of \Omegas. Finally, the refractive index enhancement is predicted for a wide spectral region.  相似文献   
45.
Optical responses in dilute composites are controlled through the local dielectric resonance of metallic clusters. We consider two located metallic clusters close to each other with admittances \varepsilon1 and \varepsilon2. Through varying the difference admittance ratio \eta [ = (\varepsilon2- \varepsilon 0) / (\varepsilon1- \varepsilon0)], we find that their optical responses are determined by the local resonance. There is a blueshift of absorption peaks with the increase of \eta. Simultaneously, it is known that the absorption peaks will be redshifted by enlarging the cluster size. By adjusting the nano-metallic cluster geometry, size and admittances, we can control the positions and intensities of absorption peaks effectively. We have also deduced the effective linear optical responses of three-component composites \varepsilone= \varepsilon0 \bigl(1 + \sumn=1^{ns} [(\gamman2+ \eta \gamman2)/({\varepsilon0(s - sn))]} \bigr), and the sum rule of cross sections: \sumn=1^{ns} {(\gamman2+ \eta \gamman2 ) = Nh1+ Nh2, where Nh1and Nh2 are the numbers of \varepsilon1 and \varepsilon2 bonds along the electric field, respectively. These results may be beneficial to the study of surface plasmon resonances on a nanometre scale.  相似文献   
46.
We report on the experimental investigation carried out in the polarisation characteristics of femtosecond pulsed and continuous wave beams propagating through a 1×2 fibre coupler. It is demonstrated that the polarisation states of pulsed and continuous wave illumination over the broad wavelength range can be preserved in a conventional fused fibre coupler. Furthermore, the fibre coupler acts as a low-pass spectral filter in the visible wavelength range with a splitting ratio between 99.6/0.4 and 99.7/0.3. The result is of importance for fibre-optic second harmonic generation microscopy which requires the polarisation preservation to extract molecular organization of a sample.  相似文献   
47.
Using molecular-dynamics simulation, we study the explosive boiling of thin liquid-argon films adsorbed on a metal surface. This process might be induced by heating the metal substrate by an ultra-fast laser. Upon sudden heating of the metal to temperatures well beyond the critical temperature of Ar, the film starts boiling. While thin films, with thickness below seven monolayers, fragment completely, in larger films only the near-surface Ar layers vaporize. The resulting vapor pressure drives the expansion of the remaining liquid overlayers. By monitoring the space and time dependence of the hydrodynamic variables density, pressure, and temperature, as well as the local thermodynamic state in the Ar sample, we obtain a detailed microscopic picture of the explosive boiling process. Finally, as a result of the fragmentation process, the abundance distribution of the clusters formed in the expansion follows a power-law distribution for cluster sizes m ≲ 10.  相似文献   
48.
The effect of bismuth on the optical properties of InGaAsBi/GaAs quantum well structures is investigated using the temperature-dependent photoluminescence from 12 K to 450 K.The incorporation of bismuth in the InGaAsBi quantum well is confirmed and found to result in a red shift of photoluminescence wavelength of 27.3 meV at 300 K.The photoluminescence intensity is significantly enhanced by about 50 times at 12 K with respect to that of the InGaAs quantum well due to the surfactant effect of bismuth.The temperature-dependent integrated photoluminescence intensities of the two samples reveal different behaviors related to various non-radiative recombination processes.The incorporation of bismuth also induces alloy non-uniformity in the quantum well,leading to an increased photoluminescence linewidth.  相似文献   
49.
Based on cyanine dye probe oxazole yellow (YO) and Cy3, a series of novel styryl cyanine dyes were designed and synthesized. Carbazole was inserted into the structures of YO and Cy3 to act as a bridge to link the benzoxazole and indole group. This modification resulted in a novel kind of benzoxazole indole styryl cyanine dye with a carbazole-bridged chain. The dyes were characterized by 1HNMR and MS. The spectra of the novel dyes were also performed and the results showed that the maximum emission wavelength of the carbazole styryl cyanine dye was shifted red, the Stokes shift increased and the fluorescence intensity enhanced compared with those of YO and Cy3. These results indicated that the novel dye could be used as an excellent fluorescent probe in biological labeling.  相似文献   
50.
利用新研制的聚变反应速率测量系统,在神光Ⅲ原型装置上测量了间接驱动时充DT气体的玻璃球壳内爆靶丸的聚变反应速率的时间历程,获得了DT中子产额约为1010时的聚变反应速率随时间的变化过程,发现了聚变中子发射在时间上的双峰结构。利用辐射流体程序对聚变中子在时间上的双峰结构进行了数值模拟,发现双峰结构分别由冲击压缩过程和惯性压缩过程产生,靶丸壳层厚度不同时产生的聚变中子发射双峰强度比变化可能是由靶丸的初始表面调制度不同所致。通过理论模拟与实验结果的对比,验证了中子聚变反应历程的双峰结构。  相似文献   
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