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排序方式: 共有1211条查询结果,搜索用时 31 毫秒
911.
912.
A practical method was described for determining Al, B, Co, Cr, Cu, Fe, Mg, Mn, Pb, and Zn in various vinegar samples using microwave induced plasma optical emission spectrometry (MIP OES). Prior to analysis, vinegar samples were diluted to appropriate volumes and then directly aspirated to the plasma. All determinations were performed using aqueous standards for calibration. The analytes added to the vinegar samples were recovered quantitatively (between 93 and 104 %). The LOD values for Al, B, Co, Cr, Cu, Fe, Mg, Mn, Pb, and Zn were 0.62, 7.67, 4.55, 0.52, 1.22, 5.72, 1.32, 0.35, 2.42, and 26.0 μg L?1, respectively. Finally, the analyte concentrations in various types of vinegar samples produced in Turkey were determined and found below maximum allowable values stated by the Turkish Food Codex.  相似文献   
913.
The aim of this study is to put forward Turkey as a case study of the applicability of the European approach to landscape characterisation studies at the local scale within the context of the European Landscape Convention. For this purpose, a classification of landscape types with the help of LANMAP typology is suggested at the European scale in a basin in Turkey where there are obvious differences in terms of landscape characteristics. In particular, this study examines the usability of a countrywide thematic database when making this classification. It is understood that a mapping system as well as a common nomenclature of types of land covered at the country scale is insufficient for the suggested methodology for Europe. Later, results of the continuation of a classification system at the local scale for landscape characterisation are discussed, and some deficiencies of LANMAP when characterising the landscapes at this scale are mentioned.  相似文献   
914.
Abstract

A new mixed quantitative and qualitative simulation methodology based on fuzzy inductive reasoning is presented. The feasibility of this methodology is demonstrated by means of a simple hydraulic control system. The mechanical and electrical parts of the control system are modeled using differential equations, whereas the hydraulic part is modeled using fuzzy inductive reasoning. The technique is described in detail in the first part of this paper. The example is shown in the second part of the paper. The mixed quantitative and qualitative model is simulated in ACSL, and the simulation results are compared with those obtained from a fully quantitative model. The example was chosen as a simple to describe, yet numerically demanding process whose sole purpose is to prove the concept. Several practical applications of this mixed modeling technique are mentioned in the paper. but their realization has not yet been completed  相似文献   
915.
The paper examines the long-run relationships between the spot and future prices of Istanbul Stock Exchange 30 index (ISE-30) and foreign currencies including the Turkish Lira-US Dollar (TL/USD) and Turkish Lira-Euro (TL/EUR). We analyze the weekly data covering the period from February 9, 2005 to October 17, 2012. Considering structural breaks is important for our analysis since our period consists of recent financial crisis. Therefore, we employ the unit root tests developed by Carrion-i-Silvestre et al. (2009) and the Maki’s (2012) cointegration test allowing for an unknown number of breaks. We find that spot and the futures prices are cointegrated in the long-run after we consider structural breaks in our data. Our results indicate that the markets are efficient.  相似文献   
916.
917.
In this article, briefly the Smith chart is mapped with an artificial neural network (ANN) covering its whole details to be exploited CAD of the microwave circuitry. Thus, relative to the similar works in the existing literature, this article provides the continuous Smith chart domain to facilitate the “Smith chart” methodology in solving the highly nonlinear transformation equations between the rectangular impedance and polar reflection planes for an infinite number of passive impedance to be used in design tasks of the microwave circuits. Data ensembles for the training and testing processes are obtained from the systematically selected locations on the Smith chart with the adaptive radius sampling algorithm. The ANN architecture is also simple, which consists of the two simple multilayer perceptron (MLP) modules with the common inputs which are the termination ZS = RS + jXS, line {?, Z0} operation bandwidth B between the defined fmin, fmax and the dielectric ε. Briefly, the outputs of these ANN modules are the standing waves and the impedance transformation, which are the characteristic features of the transmission line circuits. Activation of the hidden layers of the modules are performed by the tangential‐sigmoid type of function while the output layers are activated linearly. Furthermore, the neural unit element (NUE) is defined by the two independent neural networks as problems in the forward and reverse directions to be incorporated into the analysis and design algorithms of the unit element (UE). This can also be considered as solving the simultaneous nonlinear equation set for (?, Z0) parameters of the required impedance transformations ZOUT(ω) = ROUT (ω) + XOUT (ω) from the given complex termination ZS = RS + jXS. Applications of the Neural Smith chart are given by the numerous examples with the proved accuracy. Thus it has been verified that this neural Smith chart can be exploited for the whole classical transmission line theory including impedance matching. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.  相似文献   
918.
This paper introduces and analyzes a numerical method based on discontinuous finite element methods for solving the two-dimensional coupled problem of time-dependent incompressible Navier-Stokes equations with the Darcy equations through Beaver-Joseph-Saffman’s condition on the interface. The proposed method employs Crank-Nicolson discretization in time (which requires one step of a first order scheme namely backward Euler) and primal DG method in space. With the correct assumption on the first time step optimal error estimates are obtained that are high order in space and second order in time.  相似文献   
919.
920.

The aim of this paper is to obtain communication resource based on the overlay method for the secondary user (SU) in the primary communication environment operating in the Stop-and-Wait Hybrid Automatic Repeat Request (SW-HARQ) protocol. Unlike the overlay Cognitive Radio applications in the literature, in this work communication resources have been obtained for the SU in the time period in which the primary user (PU) is active in the channel. Our performance results have shown that a significant amount of sources of communication can be achieved for the SU by evaluating the waiting times in the primary SW HARQ periods, even when the PU is continuously running in the SW HARQ protocol without emptying the channel.

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