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51.
Ultraviolet absorption spectroscopy, has an immense potential for characterization of aromatic hydrocarbons in distillate petroleum fractions. The second derivative ultraviolet spectroscopy has improved the understanding of complex aromatic structures, such as polynuclear aromatics, which are present in gas oil fractions. Normal and second derivative ultraviolet spectroscopy of gas oils and their separated fractions are discussed in detail and conclusions are drawn regarding mono-di-and polynuclear aromatics in various gas oils. 相似文献
52.
A. Garg P.S. Sastry M. Pandey U.S. Dixit S.K. Gupta 《Nuclear Engineering and Design》2007,237(3):230-239
Numerical simulation of natural circulation boiling water reactor is important in order to study its performance for different designs and under various off-design conditions. Numerical simulations can be performed by using thermal-hydraulic codes. Very fast numerical simulations, useful for extensive parametric studies and for solving design optimization problems, can be achieved by using an artificial neural network (ANN) model of the system. In the present work, numerical simulations of natural circulation boiling water reactor have been performed with RELAP5 code for different values of design parameters and operational conditions. Parametric trends observed have been discussed. The data obtained from these simulations have been used to train artificial neural networks, which in turn have been used for further parametric studies and design optimization. The ANN models showed error within ±5% for all the simulated data. Two most popular methods, multilayer perceptron (MLP) and radial basis function (RBF) networks, have been used for the training of ANN model. Sequential quadratic programming (SQP) has been used for optimization. 相似文献
53.
54.
A dc glow discharge apparatus for preparing amorphous silicon films from silane gas is described. The films are characterized
by electron microscopy, infrared spectroscopy, electrical conductivity and photoconductivity. The deposition parameters which
give good photoconducting films are established. The Staebler-Wronski effect is studied and is found to be smaller in vacuum
than in air. A photovoltage is observed in structures with gold as the Schottkybarrier metal. The conversion efficiency of
the device is about 1%. The results are compared with those in the literature, and the improvements which might result in
a better conversion efficiency are pointed out. 相似文献
55.
The application of electrogenerated iodonium ion, acting as catalytic electron carrier, has been taken into account in the intramolecular oxidative cyclization reaction of 2-nitroaniline on graphite anode in the preparation of benzofuroxan, which is of great synthetic utility. 相似文献
56.
We investigated the effect of the somatosensory functions to the outcomes of motor functions in 28 patients with thalamic hemorrhage. The disturbance of the pyramidal tracts was assessed by the destruction of the internal capsule found in computed tomography (CT). The disturbance of the somatosensory function was analyzed by the N20 component of short-latency somatosensory evoked potentials (SSEP). The outcomes of motor function was evaluated after 3 months of ictus. Correlations between the outcomes of motor function, disturbance of the pyramidal tract, and disturbance of the somatosensory function were discussed. The result indicated that functional outcomes statistically correlated with neither disturbance of the internal capsule alone nor disturbance of N20 alone. But, there was statistically significant between functional outcomes and the combination of disturbance of the internal capsule with disturbance of N20 (p < 0.05, Wilcoxon signed-rank). There was not statistical difference in hematoma volume or consciousness. The implications of these results suggest that somatosensory function may affect the recovery of motor functions. 相似文献
57.
The radical polymerization of acrylonitrile (AN) with α-picolinium p-chlorophenacylid (α-PCPY) as initiator using carbon tetrachloride as inert solvent was investigated at 50°C. The polymerization follows ideal kinetics: the exponent values calculated for the initiator and monomer were found to be 0.5 and unity, respectively. A free radical mechanism with bimolecular termination was confirmed by the inhibiting effect of hydroquinone, a radical quencher. The rate of polymerization was a direct function of initiator (α-PCPY) concentraction, monomer (AN) concentration and temperature. The overall activation energy calculated was 56 kJ/mol. The polymerization was favoured by polar solvents and retarded by non-polar solvents. 相似文献
58.
BACKGROUND: Pulmonary infections continue to be a major cause of morbidity and mortality in patients with sickle cell disease (SCD). METHODS: In this study cell-mediated immunity in vitro was evaluated in 62 SCD patients (62 steady state and 16 with acute pneumonia) and compared with 44 normal controls (30 healthy and 14 with acute pneumonia). Lymphocyte blastogenic responses to phytohemagglutinin, tetanus toxoid and Candida albicans antigen were assessed in all subjects. In addition production of tumor necrosis factor, alpha- and gamma-interferon (IFN) were assayed. RESULTS: The results revealed comparable blastogenic responses to all three stimuli in all subjects except SCD patients with pneumonia. This group showed poor responses to all stimuli. The mean counts per minute were decreased 65 to 90% when compared with the other patients. Cytokine production of IFN-alpha and TNF was equivalent in all subjects. Conversely IFN-gamma production in both SCD groups, steady state (35 +/- 6 U/ml) and SCD with pneumonia (14 +/- 6 U/ml), was significantly decreased when compared with those in normal healthy controls (65 +/- 14 U/ml) and with pneumonia (48 +/- 17 U/ml). On analysis of individual titers 15 of 62 (24%) steady state and 10 of 16 (63%) SCD patients with pneumonia were deficient in IFN-gamma production in vitro. CONCLUSIONS: Acute pulmonary infections seem to have a profound effect on cell-mediated immunity in SCD. IFN-gamma deficiency, along with quantitative and qualitative T cell abnormalities, may represent significant factors to explain the frequent and severe infections seen in SCD. 相似文献
59.
Programmed cell death, or apoptosis, is a process of fundamental importance to cellular homeostasis in metazoan organisms (Ellis, R. E., Yuan, J., and Horvitz, H. R. (1991) Annu. Rev. Cell Biol. 7, 663-698). The caspase family of mammalian proteases, related to the nematode death protein CED-3, plays a crucial role in apoptosis and inflammation. We report here the isolation and characterization of a new caspase, tentatively termed ERICE (Evolutionarily Related Interleukin-1beta Converting Enzyme). Based on phylogenetic analysis, ERICE (caspase-13) is a member of the ICE subfamily of caspases which includes caspase-1 (ICE), caspase-4 (ICErel-II, TX, ICH-2), and caspase-5 (ICErel-III, TY). Overexpression of ERICE induces apoptosis of 293 human embryonic kidney cells and MCF7 breast carcinoma cells. Like other members of the subfamily, ERICE is not activated by the serine protease granzyme B, a caspase-activating component of cytotoxic T cell granules. Therefore, ERICE most likely does not play a role in granzyme B-induced cell death. ERICE, however, was activated by caspase-8 (FLICE, MACH, Mch-5), the apical caspase activated upon engagement of death receptors belonging to the tumor necrosis factor family. This is consistent with a potential role for ERICE in this receptor-initiated death pathway. 相似文献
60.
Caspases: intracellular signaling by proteolysis 总被引:2,自引:0,他引:2
The standard working assumption of careful CRT imaging is that each pixel is imaged independently, through a point nonlinearity (the monitor's gamma function, relating screen luminance to input voltage), and then blurred by the point-spread function of the beam spot on the phosphor. Unfortunately most monitors have inadequate video bandwidth, DC restoration, and high-voltage regulation to live up to this ideal model. Two tests are recommended for assessing a CRT's deviation from the pixel-independence model. 相似文献