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61.
    
The effects of ozone (O3) gas exposure at various concentrations and treatment times on structural, mechanical and barrier properties of polyethylene and polyamide films were investigated. Changes in the structure of the films were monitored using an FT‐IR spectrometer. The results showed that O3 treatment affected polyethylene and polyamide films differently. While O3 treatment caused formation of oxygen‐containing functional groups and degradation of polymeric chains in polyethylene films, O3 treatment of polyamide films significantly increased the –C–N– stretch observed at 1125 cm?1 in the FT‐IR spectra. The changes in the mechanical properties of polyethylene films depended on the O3 treatment conditions (temperature and O3 concentration were the most significant), but an increase in tensile strength of polyamide films was observed regardless of the treatment conditions. Permeability to O2 for both types of films decreased with increasing O3 treatment time. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
62.
This study investigated nm23 protein expression in renal cell carcinomas to determine the relationship between nm23 protein expression and grade, stage, prognosis and the cell type. 89 cases were examined by immunohistochemistry. Tubular epithelia were homogeneously stained. Cytoplasmic nm23 protein levels were reduced in renal cell carcinoma. nm23 protein levels persisted in oncocytomas, which are accepted to be benign. Cytoplasmic nm23 staining intensity did not show any correlation with stage and grade of tumor nor prognosis. Reduction in nm23 protein levels may have a role during renal cell carcinoma pathogenesis but not in progression or metastasis suppression.  相似文献   
63.
Ageing affects the mechanical properties of skin. Studies using objective measurements on facial skin have been rare and yielded contradictory information. In the present study, the age-related changes occurring in the mechanical properties of facial skin were reviewed using a computerized suction method. A total of 200 healthy women, aged from 17 to 68 years, were enrolled. Data show a significant increase in skin extensibility and a significant decline in elasticity with ageing. These changes become obvious in women approaching 40 years.  相似文献   
64.
65.
    
In this study, engineering thermoplastic composites were prepared from natural fiber blend–filled nylon 6. Natural fiber blend from a mixture of kenaf, flax, and hemp fibers were added to nylon 6 using melt mixing to produce compounded pellets. The natural fibers/ nylon6 composites with varying concentrations of natural fibers (from 5 to 20 wt%) were prepared by injection molding. The tensile and flexural properties of the nylon 6 composites were increased significantly with the addition of the natural fiber blend. The maximum strength and modulus of elasticity for the nylon 6 composites were achieved at a natural fiber blend weight fraction of 20%. The Izod impact strength of composites decreased with the incorporation of natural fibers without any surface treatments and coupling agent. The melt flow index (MFI) also decreased with increasing natural fiber blend loading. The results of tensile and flexural modulus of elasticity (FMOE) are in accordance with the rheological data from the MFI measurements. The increase in the tensile and flexural properties indicated that efficient bonding occurred between the natural fibers and nylon 6. No fiber pullout was observed during the scanning electron microscopic analysis of the fracture surfaces. The higher mechanical results with lower density demonstrate that a natural fiber blend can be used as a sufficient reinforcing material for low‐cost, eco‐friendly composites in the automotive industry and in other applications such as the building and construction industries, packaging, consumer products, etc.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers  相似文献   
66.
Monovarietal extra virgin olive oils extracted from six dominant and economically important Turkish olive cultivars (memecik, erkence, domat, nizip-yaglik, gemlik, ayvalik) were examined for their simple phenolics, phenolic acids and flavonoid compounds over 2005 and 2006 harvest years. Total phenol contents, oxidative stabilities and chromatic ordinates as colour parameters were also measured. The most typical phenolic compounds that were identified in both years are hydroxytyrosol, tyrosol, vanillic acid, p-coumaric acid, cinnamic acid, luteolin, and apigenin. Multivariate data were analysed by principal component and partial least square-discriminant analyses. It was observed that phenolic profiles of olive oils depended highly on harvest season. In addition, oils of different olive cultivars have different distribution of phenols. No significant correlation was observed between oxidative stability and phenolic compounds. Increase in peroxide value over an accelerated oxidation period of 11 days showed weak correlations with total phenol content, vanillin, syringic acid and colour parameter a, as 0.56, 0.55, −0.42, and 0.51, respectively, in terms of correlation coefficient r.  相似文献   
67.
ABSTRACT

Spectral Line-Based Weighted Sum of Gray Gases (SLW) model was implemented to Computational Fluid Dynamics (CFD) Solver, ANSYS FLUENT. Discrete Ordinate Method (DOM) available in ANSYS FLUENT was used as Radiative Transfer Equation (RTE) Solver. ANSYS FLUENT with SLW was applied to the prediction of incident heat fluxes for three test problems; two containing isothermal homogenous/nonhomogenous water vapor and one isothermal water vapor/carbon dioxide mixture. Predictive accuracy of SLW in ANSYS FLUENT was assessed by benchmarking its predictions against those of ray tracing (RT) with Statistical Narrow-Band (SNB) and Method of Lines (MOL) solutions of DOM with SLW. Comparisons reveal that the results of CFD code are in good agreement with the benchmark solutions. This finding proves that the use of DOM with SLW in CFD codes would provide more accurate solutions in studies involving gas combustion, where accuracy in spectral radiative properties plays dominant role in heat flux predictions.  相似文献   
68.
M. Ozdemir  Banu F. Ozen  John D. Floros 《LWT》2008,41(10):2044-2050
Osmotic dehydration of diced green peppers was optimized with respect to temperature (20-40 °C), time (15-600 min), salt (0-10 g/100 g) and sorbitol (0-10 g/100 g) concentrations through response surface methodology. Water loss (WL), solids gain (SG), salt uptake (SA) and sorbitol uptake (SO) were the responses in a 24 central composite rotatable design. Models developed for all responses were significant (p ≤ 0.01) without significant lack of fit. Results suggested that optimum processing conditions of 5.5 g salt/100 g and 6 g sorbitol/100 g at 30 °C after 240 min would result in WL = 23.3%, SG = 4.1%, SA = 8 g/100 g dry pepper and SO = 2.4 g/100 ml extract.  相似文献   
69.
Fatty acid composition and mid-infrared spectra of olive oils in combination with chemometric techniques were used in the classification of Turkish olive oils with respect to their varieties, growing location and harvest year. In particular, olive oil samples belonging to five different cultivars were obtained from the same orchard in the middle part of Aegean region and two of these varieties were also received from another orchard in northern part of the same region of Turkey in two consecutive harvest years. Evaluation of nine different fatty acid compositions with principal component analysis revealed clear differentiation with respect to variety, geographical origin and harvest year. On the other hand, mid-infrared spectra also achieved varietal and seasonal discrimination to some extent, but differentiation is not as clear as that obtained using fatty acid compositions.  相似文献   
70.
    
The effects of interesterified vegetable oils (IVOs) prepared from palm, cottonseed and olive oil, respectively, and sugarbeet fiber (SBF) on quality of frankfurters have been studied. Beef fat (10%) was replaced by one of the IVOs for 60% and 100%. Incorporation of IVOs in frankfurters improved the nutritional content of product due to altering the fatty acid composition. The oleic acid content of frankfurters increased from 28.76% to 45.57% and 47.15% as the interesterified palm oil (IPO) and interesterified olive oil (IOO) contents increased from 0% to 10% and 6%, respectively. The linoleic acid contents of 6% and 10% interesterified cottonseed oil (ICO) added frankfurters were, respectively, 10- and 19.6-fold higher than treatments without ICO. Addition of SBF (<425 μm size and 1% level) significantly increased (p<0.05) the total dietary fiber content and water-holding capacity (WHC) of frankfurters. Incorporation of IVOs and SBF did not lead to significant changes in appearance, colour, texture, flavour or sensory scores. It is concluded that IVOs and SBF may be successfully applied as beef fat substitute in frankfurters since this combination offset some of the changes brought about by beef fat replacement.  相似文献   
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