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11.
S K Samanta U C Gupta R K Sharma 《The Journal of the Operational Research Society》2007,58(3):368-377
This paper investigates a discrete-time single-server finite-buffer queueing system with multiple vacations in which arrivals occur according to a discrete-time renewal process. Service and vacation times are mutually independent and geometrically distributed. We obtain steady-state system length distributions at prearrival, arbitrary and outside observer's observation epochs under the late arrival system with delayed access and early arrival system. The analysis of actual waiting-time for both the systems has also been carried out. The model has potential application in high-speed computer network, digital communication systems and other related areas. 相似文献
12.
A finite element solution of the Navier-Stokes equations for steady flow under the magnetic effect through a double-branched two-dimensional section of a three-dimensional model of the canine aorta is discussed. The numerical scheme involves transforming the physical co-ordinates to a curvilinear boundary-fitted co-ordinate system. The shear stress at the wall is calculated for a Reynolds number of 1000 with the branch-to-main aortic flow rate ratio as a parameter. The results are compared with earlier works involving experimental data and found to be in reasonable qualitative agreement. The steady flow, shear stress and branch flow under the effect of a magnetic field have been discussed in detail. 相似文献
13.
14.
A convenient and enantioselective synthesis of ethyl (8RS, 15R)-8-acetoxy-15-hydroxyhexadecanoate15 via a chemoenzymatic approach has been described. The salient features of the synthesis were operational simplicity, use of easily accessible materials, and excellent enantiocontrol via lipase catalyzed acetylation of 2-alkanol. 相似文献
15.
S K Deshpande S M Chaudhari Ashok Pimpale A S Nigavekar S B Ogale V G Bhide 《Pramana》1991,37(4):373-385
An automated linear laboratory EXAFS spectrometer of the Johansson type has been indigenously developed. Only two translational
motions are required to achieve the necessary Rowland circle configuration for the (fixed) X-ray source, the dispersing and
focusing bent crystal and the receiving slit. With the available crystals the spectral region from 5 to 25 keV can be scanned.
The linear motions of the crystal and receiving slit including the detector assembly are achieved by employing software-controlled
DC motors and utilizing optical encoders for position sensing. The appropriate rotation of the crystal is achieved by the
geometry of the instrument. There is a facility to place the sample alternately in the path of the X-ray beam and out of the
path to record both the incident X-ray intensityI
0 and the transmitted intensityI employing the scintillation detector. An arrangement with a two-window proportional detector before the sample to measureI
0 and the scintillation detector to recordI is also developed; in this case it is not necessary to oscillate the sample. Fast electronic circuits are employed to minimize
counting errors. The instrument is user-friendly and it is operated through a menu-driven IBM compatible PC. EXAFS spectra
of high resolution have been recorded using the spectrometer and employing the Si(111) reflecting planes; the X-ray source
being a Rigaku 12 kW rotating anode with Cu target. We describe the spectrometer and discuss its performance with a few representative
spectra. 相似文献
16.
Anuradha Sharma Gurmeet K. Bakshi Madhu Raka 《Finite Fields and Their Applications》2007,13(4):1071-1085
Polyadic codes constitute a special class of cyclic codes and are generalizations of quadratic residue codes, duadic codes, triadic codes, m-adic residue codes and split group codes, which have good error-correcting properties. In this paper, we give necessary and sufficient conditions for the existence of polyadic codes of prime power length. Examples of some good codes arising from the family of polyadic codes of prime power length are also given. 相似文献
17.
The lantadenes fraction from Lantana camara was isolated and transformed to the medicinally important intermediate 22β-hydroxyoleanonic
acid. The compound was studied for hepatotoxicity using lantadene A as standard and found to be nontoxic.
Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 357–358, July–August, 2006. 相似文献
18.
An energy-dependent partitioning scheme is explored for extracting a small number of eigenvalues of a real symmetric matrix with the help of genetic algorithm. The proposed method is tested with matrices of different sizes (30 × 30 to 1000 × 1000). Comparison is made with Löwdin’s strategy for solving the problem. The relative advantages and disadvantages of the GA-based method are analyzed 相似文献
19.
This article presents the comparison of approximate and exact small-signal theories for analyzing the influence of the higher-order dispersion terms on dispersive optical communication systems operating near zero dispersion wavelength for linear single-mode fiber. For the approximate theory, the generalized conversion matrix has been reported and gives the transfer function of intensity and phase from the fiber input to fiber output for a laser source including the influence of any higher-order dispersion term. In addition, expressions for the small-signal frequency response and the relative intensity noise (RIN) response of an ultrafast laser diode including noises are derived. However, it is observed that the approximation assumed for the second-order dispersion term for the approximate analysis is not valid. From the approximate theory, the exact generalized conversion matrix and exact expressions for small-signal frequency response and relative intensity noise (RIN) are obtained. We show that for the exact theory, the second-order dispersion term has no effect on intensity and frequency response even at large modulating frequencies and large propagation distances contrary to the approximate theory as reported by other authors. But we show that third-order dispersion term certainly has some minute impact on the frequency and RIN response for long distance links at high modulating frequencies. 相似文献
20.
Let R be a prime ring of char R≠2, d a non-zero derivation of R and ρ a non-zero right ideal of R such that [[d(x),d(y)]n [y,x]m] = 0 for all x,y ∈ ρ or [[d(x),d(y)]n d[y,x]m] = 0 for all x,y ∈ ρ, n, m ≥ 0 are fixed integers. If [ρ,ρ]ρ ≠ 0, then d(ρ)ρ = 0. 相似文献