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91.
In a grave illness the homeostasis of some elements may be upset either by the disease process per se, or by the therapy adopted. Patients with pyogenic, viral and tubercular meningo-encephalitis were targets of interest. 108 subjects' serum and cerebrospinal fluid (CSF) compartments were assayed for magnesium, calcium, zinc and copper, by atomic absorption spectrometry. Results showed that the serum pool was more intensely altered than the CSF pool in the case of magnesium and calcium but the reverse occurred for zinc and copper. No organism-dependent change was noted, but comatosed patients were the worst effected. These findings are discussed with respect to the relative brain and CSF content of each element and the patho-physiology which could alter the compartments studied.  相似文献   
92.
Monthly Rainfall Prediction Using Wavelet Neural Network Analysis   总被引:6,自引:1,他引:6  
Rainfall is one of the most significant parameters in a hydrological model. Several models have been developed to analyze and predict the rainfall forecast. In recent years, wavelet techniques have been widely applied to various water resources research because of their time-frequency representation. In this paper an attempt has been made to find an alternative method for rainfall prediction by combining the wavelet technique with Artificial Neural Network (ANN). The wavelet and ANN models have been applied to monthly rainfall data of Darjeeling rain gauge station. The calibration and validation performance of the models is evaluated with appropriate statistical methods. The results of monthly rainfall series modeling indicate that the performances of wavelet neural network models are more effective than the ANN models.  相似文献   
93.
94.
The aim of the present work is to get an insight of the phenomena behind the low-pressure low-power transients that occur during startup of a natural circulation boiling system. A RELAP5 model developed for a test facility and its prototype is used to record additional system parameters that were not included in the data obtained from experiments. The flow oscillations observed during experimental and numerical studies are analyzed and classified. It is inferred that the low amplitude oscillations are not condensation induced geysering instabilities, but a density wave instability supported by flashing. The similarity between the nature of startup transients observed in the test facility and the prototype is also examined. The effect of flashing is more pronounced in the prototype due to the strong variation of saturation temperature as the length scale is 4 times that of the model. The time series data obtained from experimental observations and numerical simulations are analyzed to identify the structural nature of flow oscillations. The power spectral density estimated using fast Fourier transform (FFT) algorithm illustrates the chaotic nature of the signals. The nonlinear time series analysis (TISEAN) package has been used for the estimation of Lyapunov exponent and the Poincaré section. The Poincaré section and the Lyapunov exponent confirm the chaotic nature of the flow oscillations.  相似文献   
95.
Present work deals with findings on dielectric relaxation behaviour and a.c. conduction in a SiO2-doped polymer nanocomposite electrolyte system, namely, [(100 − x)PEO + xSiO2]:yNH4SCN. The formation of nanocomposite has been ascertained by XRD measurements. The effect of salt and filler (SiO2) on conductivity response of PEO-based nanocomposite polymer electrolyte has been investigated by impedance spectroscopy. The variation of dielectric permittivity, dielectric loss and modulus spectra with frequency and temperature was carried out from impedance spectroscopy data. The a.c. conductivity seems to follow the universal power law.  相似文献   
96.
Variation of ultrasonic attenuation and velocities with temperature have been evaluated in the temperature range 5-50 K due to electron-phonon interaction mechanism in transition metals vanadium, niobium and tantalum for longitudinal and shear waves. For this evaluation, we have also computed the second order elastic constants using Morse potential. Behaviour of acoustical phonons in these bcc metals is different from other normal metals, intermetallics, semimetallics and alloys. Some characteristic features of these materials connected to ultrasonic parameters are discussed.  相似文献   
97.
DK 《电声技术》2009,33(3):91-91
UK10-A系列适用于各种固定安装的高档演艺吧、慢摇吧及现场表演。该系列采用高功率扬声器单元和轻巧的箱体搭配,通过计算机优化设计,达到平滑的特性、展宽的频响特点和良好的控制覆盖性能。  相似文献   
98.
99.
Response surface methodology was used to optimize the concentration of important metal salts screened by Placket–Burman design. Eight metal salts such as CaCl2, CoCl2, CuSO4, FeCl3, MgSO4, MnSO4, NaCl and Pb(NO3)2 were tested by using Placket–Burman design criterion and four salts viz. CaCl2, MgSO4, MnSO4 and NaCl showed significant effect (P < 0.05) on alkaline phosphatase production. The metal salts concentration was optimized by applying central composite design (CCD) and the most suitable metal salts composition for alkaline phosphatase production in 100 ml medium was CaCl2 – 0.083 g; MgSO4 – 0.041 g; MnSO4 – 0.037 g and NaCl – 0.34 g. At these optimum levels of metal salts, alkaline phosphatase production of 2778.92 U/ml was obtained. 1.53-fold increase in the alkaline phosphatase yield was observed after selection and optimization of metal salts for alkaline phosphatase production by response surface methodology.  相似文献   
100.
Significant structure theory (SST) of Eyring has been employed to calculate theoretically the viscosity of binary molten electrolytes on the basis of rigid sphere model. For KClNaCl and KClKBr systems the agreement between theoretical and experimental values is found to be satisfactory.  相似文献   
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