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171.
Utaro Furukane Toshiatsu Oda 《Journal of Quantitative Spectroscopy & Radiative Transfer》1985,33(6):645-651
Lasing conditions for He have been evaluated numerically. We have used a collisional radiative model to calculate overpopulation densities Δnij, which are defined as differences between population densities per unit statistical weight of the upper and lower excited levels i and j, respectively. Laser oscillations for the level pairs 21P-31S, 21P-41S, 21P-31D, 21P-41D, 31D-41F, 31P-41S, 31P-41D, and 33P-43S are possible when the electron densities are within well defined limits at low electron temperature (Te = 0.1 eV). For level pairs of the singlet state, the inversion mechanism for He is the same as for H. Only collisional processes produce population inversion in the triplet level pair 33P-43S. 相似文献
172.
R.?GilardiEmail author S.?Streule N.?Momono M.?Oda J.?Mesot 《The European Physical Journal B - Condensed Matter and Complex Systems》2005,47(2):231-237
Magnetization and ac-susceptibility measurements are used to
characterize the mixed phase of the high-temperature cuprate
superconductor La2-xSrxCuO4 over a large range of doping (0.075
0.20). The first order vortex lattice phase transition line HFOT(T), the upper
critical field Hc2(T) and the second peak Hsp(T) have been
investigated up to high magnetic fields (8 Tesla applied perpendicular to the CuO2 planes).
Our results reveal a strong doping dependence of the magnetic phase diagram, which can mainly be
explained by the increasing anisotropy with underdoping.
Within our interpretation, the first order vortex lattice phase transition is due to the sublimation (rather than melting)
of the vortex lattice into a gas of pancake vortices, whereas the second peak is related to the transition to a more disordered
vortex glass state. 相似文献
173.
Kanthen?K?HarikrishnanEmail author Hiroaki?Ishii 《Fuzzy Optimization and Decision Making》2005,4(2):141-147
We consider a batch scheduling problem on a single machine which processes jobs with resource dependent setup and processing time in the presence of fuzzy due-dates given as follows:1. There are n independent non-preemptive and simultaneously available jobs processed on a single machine in batches. Each job j has a processing time and a due-date.2. All jobs in a batch are completed together upon the completion of the last job in the batch. The batch processing time is equal to the sum of the processing times of its jobs. A common machine setup time is required before the processing of each batch.3. Both the job processing times and the setup time can be compressed through allocation of a continuously divisible resource. Each job uses the same amount of the resource. Each setup also uses the same amount of the resource.4. The due-date of each job is flexible. That is, a membership function describing non-decreasing satisfaction degree about completion time of each job is defined.5. Under above setting, we find an optimal batch sequence and resource values such that the total weighted resource consumption is minimized subject to meeting the job due-dates, and minimal satisfaction degree about each due-date of each job is maximized. But usually we cannot optimize two objectives at a time. So we seek non-dominated pairs i.e. the batch sequence and resource value, after defining dominance between solutions.A polynomial algorithm is constructed based on linear programming formulations of the corresponding problems. 相似文献
174.
Tasuku?ToyonagaEmail author Takesh?Itoh Hiroaki?Ishii 《Fuzzy Optimization and Decision Making》2005,4(1):51-69
The main purpose of this paper is to present a crop planning problem for agricultural management under uncertainty. It is significant that agricultural managers assign their limited farmlands to cultivation of which crops in a season. This planning is called the crop planning problem and influences their incomes for the season. Usually, the crop planning problem is formulated as a linear programming problem. But there are many uncertain factors in agricultural problems, so future profits for crops are not certain values. A linear programming model with constant profit coefficients may not reflect the environment of decision making properly. Therefore, we propose a model of crop planning with fuzzy profit coefficients, and an effective solution procedure for the model. Furthermore, we extend this fuzzy model, setting the profit coefficients as discrete randomized fuzzy numbers. We show concrete optimal solutions for each models. 相似文献
175.
This study experimentally examined the explosive fragmentation of thin ceramic tubes using pulsed power. A thin ceramic tube was threaded on a thin copper wire, and high voltage was applied to the wire using a pulsed power generator. This melted the wire and the resulting vapor put pressure on the ceramic tube, causing it to fragment. We examined the statistical properties of the fragment mass distribution. The cumulative fragment mass distribution obeyed the double exponential or power law with exponential decay. Both distributions agreed well with the experimental data. Finally, we obtained universal scaling for fragmentation, which is applicable to both impact and explosive fragmentation. 相似文献
176.
177.
A nickel catalyst coordinated by trimethylphosphine is found to effect the addition reaction of Ar-CN bonds in aromatic nitriles across alkynes to give rise to various beta-arylalkenenitriles. 相似文献
178.
A rapid column-adsorption method has been developed for concentrating traces of copper, cadmium, and lead in water prior to their determinations by graphite-furnace atomic-absorption spectrometry. The adsorbent used was prepared by loading a strongly basic anion-exchanger QAE-Sephadex A-25 (50 mg) with thiacalix[4]arenetetrasulfonate (20 mol). Two-hundredfold preconcentration of the analyte elements was achieved by passing 100 mL of sample solution (pH 8.0) through a column packed with the adsorbent (6 mm i.d.×7 mm high) at a flow rate of 10 mL min–1 and by the subsequent elution with 500 L of aqueous nitric acid solution (1 mol L–1). The practical applicability of the proposed method was evaluated by analyzing certified reference seawater samples. 相似文献
179.
Ohno H Iwasaki H Eguchi T Tanaka T 《Chemical communications (Cambridge, England)》2004,(19):2228-2229
Intramolecular arylation of aryl radicals was mediated by SmI(2)/HMPA in the presence of i-PrOH to give spirocycles and/or reduced cine-cyclised products, while the reaction in the absence of i-PrOH gave the rearomatised fused rings. 相似文献
180.
Abe S Fujishima T Tsubone T Fujimura R Ono H Matoba O Oda K Shimura T Kuroda K 《Optics letters》2003,28(6):420-422
The photorefractive effect in a nominally undoped 0.91Pb(Zn1/3Nb2/3)O3-0.09PbTiO3 single crystal is measured. We report what is, to our knowledge, the first observation of the photorefractive effect in Pb-based relaxor ferroelectric crystals. The crystal is grown by the flux solution method. Then it is cut into a 2 mm x 4 mm x 8 mm piece and electrically poled along the [111] direction. The coupling constant of the two-wave mixing is 17 cm(-1), and the normalized time constant under 1-W/cm(2) illumination is 12 s at a wave-length of 476 nm. The effective trap density is calculated as 5 x 10(16) cm(-3) from the Debye screening length under the assumption of Kukhtarev's band-transport model. The dominant carrier is identified to be holes from the direction of two-wave mixing energy transfer. 相似文献