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1.
The suppression of apoptosis may contribute to the carcinogenicity of the peroxisome proliferators (PPs), a class of non-genotoxic rodent hepatocarcinogens. Our previous work demonstrated that the PP nafenopin suppressed both spontaneous and transforming growth factor beta1 (TGFbeta1)-induced hepatocyte apoptosis both in vivo and in vitro. Here, we extend these observations by demonstrating the ability of nafenopin to suppress apoptosis induced by other major candidates for the signalling of cell death in the liver. Treatment of rat or mouse hepatocyte monolayers with TGFbeta1 or the DNA damaging drugs etoposide or hydroxyurea induced high levels of apoptosis. Western blot analysis did not support a role for either p53 or p21waf1 in etoposide-induced apoptosis in rat hepatocytes. Treatment of mouse hepatocytes with an agonistic anti-Fas antibody also resulted in an induction of high levels of apoptosis. Pre-addition and continued exposure to nafenopin suppressed apoptosis induced by all three stimuli. Overall, our studies demonstrate that the ability of nafenopin to protect hepatocytes from apoptosis is not restricted to species or apoptotic stimulus. It is possible, therefore, that the PPs may suppress apoptosis by acting on diverse signalling pathways. However, it seems more likely that nafenopin suppresses hepatocyte apoptosis elicited by each death stimulus by impinging on a core apoptotic mechanism.  相似文献   
2.
This study is composed of three essential parts. The first part describes an indirect semi-experimental method which is used to reconstruct the excitation force of an operating diesel engine from the acceleration data measured at the mounting points. These internal forces can not be directly measured with force sensors; they have to be derived from the dynamic deformation of the engine support, so a theoretical analysis is carried out to derive the equations for the force re-construction.The second part deals with prevention of low frequency vibration of the powertrain from spreading to the rest of the vehicle. Three uncoupling techniques are used to minimize these vibrations. The first technique reduces the non-diagonal elements of stiffness matrix. The second technique uses the elastic axes decoupling criterion. The third technique uncouple the torque roll axis (TRA) by using the previously determined excitation efforts.In the third part, numerical and experimental results are discussed. The solicitations deducted and the positions of mounts allowing decoupling of the powertrain are presented.  相似文献   
3.
Ray-tracing techniques have proven to be very useful for the analysis and design of wireless systems both in urban microcells and in indoor picocells. At present, the optimization of these techniques enables not only the signal mean level but also the local statistics to be estimated accurately, which is of great practical importance. A wide range of comparisons between measurements and simulations confirming this have been carried out by the authors, and some examples are presented. The most interesting contribution of this paper is that starting from the signal information at one single point, obtained using ray-tracing techniques, it is possible to estimate the signal statistics in a local area of that point. This possibility substantially reduces the local statistics calculation time, confirming the idea that an efficient site specific channel model might be feasible. Finally, it is also shown that ray-tracing techniques are able to accurately estimate the first- and second-order statistics in those environments where the Clarke (1968) or isotropic scattering model is not applicable  相似文献   
4.
The objective of this study was to investigate instrumental–sensory relationships of some texture scales using argentine foods as references. Textural characteristics of these foods were instrumentally investigated by the texture profile analysis technique. Principal component analysis (PCA) was used to describe the main attributes of the food samples. High Pearson’s correlation coefficients were found between hardness and fracturability (r = 0.94; P < 0.0001), hardness and gumminess (r = 0.71; P < 0.0001) and springiness and cohesiveness (r = 0.85; P < 0.0001). PCA identified two significant principal components, which accounted for 81.2% of the variance in the instrumental data. Additionally, a trained panel described the texture characteristics of the food samples according to the standard reference scales. The correlation curves showed nonlinear relationships (R2 between 85.6% and 99.9%) which were used to predict sensory attributes of other food samples. Some texture attributes like hardness and fracturability were accurately predicted by mechanical properties, while others like cohesiveness and adhesiveness were less representative.  相似文献   
5.
Mercury content in soils near abandoned mine wastes in the mercury mining area of Mieres (Asturias, Spain) is highly elevated as a result of the long period of mining and abundant Hg production. In this work, an evaluation of Hg concentration, distribution, and mobility in three soil samples from the immediate vicinity of a chimney used for vapour evacuation during pyrometallurgical treatment of the ore was carried out. For that purpose, total Hg contents were determined for the original samples and their grain-size subsamples. The study of mercury mobility in the original samples and in the different particle-size subsamples was made by the application of a sequential extraction method. Results showed that Hg concentration in soils decreases directly with the distance from the chimney and the dispersion of Hg is not influenced by the topographic height of the site tested. The sample collected in the base of the chimney exhibited appreciable amounts of mobile Hg. In general, a higher Hg concentration was found for the finest particle-size subsamples. Hg mobility was found to be higher for quite developed soils. The sample collected downstream from the chimney showed a significant Hg mobile content as a result of a more intensive weathering. An increase of Hg mobility at decreasing particle size was found in all three analysed samples.  相似文献   
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7.
Sugarcane juice is a common beverage in many Brazilian cities. At harvesting season most sugarcane plantation is burnt and this procedure has been shown as an important source of PAHs emission. In the present study 80 samples of sugarcane juice collected from two Brazilian cities, in two different periods, were analysed for the presence of four PAHs: benz(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene and benzo(a)pyrene. PAHs were detected in 50% of the samples. The samples collected between harvests presented mean sums of PAHs of 0.013 μg/kg and 0.012 μg/kg, while the samples collected during harvest presented mean sums of 0.053 μg/kg and 0.055 μg/kg. A higher concentration and incidence of PAHs in the juices collected in the harvest period was verified, corroborating the burning of the crops as a source of sugarcane juice contamination.  相似文献   
8.
Experimental results and a method for recovering Cu, Zn, Cd, and Co from a solid hydrometallurgical residue are presented. A series of leaching, oxidation, and solvent extraction stages are the keys to the process.  相似文献   
9.
The response of Escherichia coli ATCC 11229, Listeria innocua ATCC 33090 and Zygosaccharomyces bailii NRRL 7256 in fresh‐cut pear to simultaneous and serial combined treatments involving H2O2 immersion (3% w/v; pH 3.0; 25 °C; 2.0 or 5.0 min) and UV‐C exposure (7.5 min; 3.7 kJ m?2) was investigated. For selected treatments, native flora, sensory and colour changes were also evaluated. E. coli and L. innocua were more sensitive than Z. bailii. Serial H2O2/UV‐C treatments were more effective than the simultaneous arrangement. The single effect of UV‐C was enhanced by the combination with 5 min H2O2, hence avoiding the recovery of the surviving population. The combined treatment kept optimal microbial stability and exhibited more luminosity than the single UV‐C treatment. Texture profile analysis conducted using a trained panel showed that H2O2/UV‐C processed pear discs were perceived with significantly less hardness and fracturability but as juicy as untreated discs. Consumers found them pleasant.  相似文献   
10.
Indoor MIMO Channel Modeling by Rigorous GO/UTD-Based Ray Tracing   总被引:1,自引:0,他引:1  
This paper presents a multiple-input-multiple- output (MIMO) channel model based on rigorous ray-tracing techniques, which is based on a full 3-D implementation of geometric optics and the uniform theory of diffraction (3-D GO/ UTD). Results obtained from measurements and simulations of the correlation matrix and capacity of a 2 times 2 MIMO system in specific indoor environments at a frequency of 2 GHz are presented. The channel capacity has been calculated for the different local areas considered in open- and office-area scenarios, starting from the measurements carried out there, as well as from the ray-tracing simulated channels. The rigorous and quantitative comparison between measurements and simulations shows that the model accuracy is sufficient for the analysis and design of the different aspects of the full MIMO system. The results from the ray-tracing model can also be used to extract general statistical characteristics and parameterize statistical models for different types of environments, without the need to carry out large and costly measurement campaigns. In addition, the measured data are used to study the impact of the channel on the achievable capacity of a 2 times 2 MIMO system in typical indoor scenarios at 2 GHz.  相似文献   
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