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971.
A pressure sensitive paint (PSP) measurement has been known as a pressure field measurement technique based on the oxygen quenching phenomenon of luminescence of specific luminophores. A PSP measurement was applied for pressure field measurement in a low-solidity circular cascade diffuser of a single-stage transonic centrifugal compressor with 5 in pressure ratio for HFC134a gas. The oxygen concentration was about 500 ppm. Ru (bath-phen) was adsorbed on a silica-gel thinlayer chromatography sheet, and the sheet was pasted onto the side-wall between the cascade vanes. A drastic change in luminescent intensity was recognized during a surge condition. Also the pressure variations based on luminescent intensity agreed well with the pressure fluctuations measured using a semiconductor pressure sensor with high-frequency-response. It was shown that a PSP measurement worked well to investigate the unsteady pressure fields in a circular cascade diffuser of a transonic centrifugal compressor. Moreover, the time response of PSP becomes clear as a problem to be overcome for the present. 相似文献
972.
The production system using kanban was pioneered by Toyota Motor Company in Japan and subsequently it was adopted by numerous other Japanese and US companies for applying the just-in-time manufacturing principles. This research studies a single-stage supply chain system that is controlled by kanban mechanism. The supply chain system is modelled as a mixed-integer nonlinear programming (MINLP) problem. It is solved optimally by branch-and-bound method to determine the number of kanbans, batch size, number of batches, and the total quantity over one period. Meanwhile, the kanban operation between two adjacent plants is worked out considering the factors of loading and unloading time, and transport time. Coupled with plant-wide efforts for cost control and management commitment to enhance other measures of performance, a logistics system for controlling the production as well as the supply chain system is developed, which results in minimizing the total cost of the supply chain system. The results show that the improvements in reduction of inventory, wasted labour, and customer service in a supply chain are accomplished through the kanban mechanism. 相似文献
973.
Óscar Ciaurri 《Rendiconti del Circolo Matematico di Palermo》2004,53(2):231-234
A transference theorem for multipliers of Hermite expansions is proved. The result allows to transfer weightedL
2(ℝ
n
) estimates from lower to higher dimensions.
Research of the author supported by grant BFM2003-06335-603-03 of the D.G.I.. 相似文献
974.
Summary An increasingly important problem in exploratory data analysis and visualization is that of scale; more and more data sets
are much too large to analyze using traditional techniques, either in terms of the number of variables or the number of records.
One approach to addressing this problem is the development and use of multiresolution strategies, where we represent the data
at different levels of abstraction or detail through aggregation and summarization. In this paper we present an overview of
our recent and current activities in the development of a multiresolution exploratory visualization environment for large-scale
multivariate data. We have developed visualization, interaction, and data management techniques for effectively dealing with
data sets that contain millions of records and/or hundreds of dimensions, and propose methods for applying similar approaches
to extend the system to handle nominal as well as ordinal data. 相似文献
975.
Summary This paper presents a graphical display for the parameters resulting from loglinear models. Loglinear models provide a method
for analyzing associations between two or several categorical variables and have become widely accepted as a tool for researchers
during the last two decades. An important part of the output of any computer program focused on loglinear models is that devoted
to estimation of parameters in the model. Traditionally, this output has been presented using tables that indicate the values
of the coefficients, the associated standard errors and other related information. Evaluation of these tables can be rather
tedious because of the number of values shown as well as their rather complicated structure, mainly when the analyst needs
to consider several models before reaching a model with a good fit. Therefore, a graphical display summarizing tables of parameters
could be of great help in this situation. In this paper we put forward an interactive dynamic graphical display that could
be used in such fashion. 相似文献
976.
Ladislav Adamec 《Applications of Mathematics》2005,50(2):93-101
In the theory of autonomous perturbations of periodic solutions of ordinary differential equations the method of the Poincaré mapping has been widely used. For the analysis of properties of this mapping in the case of two-dimensional systems, a result first obtained probably by Diliberto in 1950 is sometimes used. In the paper, this result is (partially) extended to a certain class of autonomous ordinary differential equations of higher dimension.This research was supported by Grant No. 201/99/0295 of the Grant Agency of the Czech Republic.This revised version was published online in April 2005 with a corrected missing date string. 相似文献
977.
Igor Wigman 《Monatshefte für Mathematik》2005,144(1):71-84
We solve an asymptotic problem in the geometry of numbers, where we count the number of singular n×n matrices where row vectors are primitive and of length at most T. Without the constraint of primitivity, the problem was solved by Y. Katznelson. We show that as T, the number is asymptotic to
for n3. The 3-dimensional case is the most problematic and we need to invoke an equidistribution theorem due to W. M. Schmidt. 相似文献
978.
Arcadiy V. Krasheninnikov Konstantin E. Kon’kov Leonid A. Openov Vladimir F. Elesin 《Czechoslovak Journal of Physics》1996,46(3):1197-1198
The effect of ion irradiation on the superconducting transition temperatureT c and resistivityρ ab (T) of YBa2Cu3O7-x films with different oxygen content (initial temperatureT c0≈90 K and 60 K) is studied experimentally. The dependenciesT c /T c0 on residual resistivityρ o are obtained in very wide range 0.2<T c /T c0 <1 andρ o μΩ·cm. The critical values ofρ o , corresponding to the vanishing of superconductivity, are found to be an order of magnitude larger then those predicted by theory ford-wave pairing. At 0.5÷0.6<T c /T c0<1 the experimental data are in close agreement with theoretical dependencies, obtained for the anisotropics-wave superconductor within the BCS-framework. 相似文献
979.
J-P Boussemart W Briec H Leleu 《The Journal of the Operational Research Society》2010,61(8):1297-1301
This note generalizes analytical relationships among activity variables of Dataenvelopment analysis models previously derived in a previous article by theauthors of this note. We relax the assumption of constant returns to scale byshowing that the key results hold under a weaker assumption of homogeneity. Weuse the notion of α-returns to scale to extend the analysis tostrictly increasing and decreasing returns, covering now the whole range ofreturns to scale for multi-output homogenous technologies. 相似文献
980.