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81.
A quantitative method is reported for the estimation of glycerol during transesterification of oil to form biodiesel. The reagent used to derivatize glycerol was 9,9-dimethoxyfluorene. Glycerol is estimated by both UV–visible spectrophotometric and high performance liquid chromatography methods. Using the former method, detection limits of 0.05% w/w of glycerol in biodiesel was established. Validation of the developed method was done using the Greenhill method for determination of free glycerol formed during the transesterification reaction.  相似文献   
82.
83.
Information integration is vital for keeping manufacturing operations competitive. A case study approach has been adopted to better understand the role of informatio in integrated manufacturing. Information is now considered a corporate asset. The creation, processing, movement and security of information is therefore as important as the products/services of an enterprise. The case studies have helped in identifying the requirements and issues involved in developing an information system and supporting software framework for a manufacturing enterprise. This paper deseribes a case study dealing with the integrated manufacture of optical fiber products. A phased development and implementation approach was adopted where a small, manageable slice of the system is considered for the case study followed by functional modeling (IDEFO) and data flow modeling (data flow diagrams). This identifies the pieces of information of interest. The information relationships are modeled using extended entity relationship (EER) diagrams which are then mapped to a relational model. The relational tables thus obtained were implemented on a commercial Database Management System (DBMS). The functional constraints and application interfaces were then built using Structured Query Languages (SQL) and commercial application interface tools. Subsequent sections describe the functional models, data flow diagrams (DFDs), EER diagrams, relational database design and user/application interfaces developed for the system. Implementation experiences and observations are discussed along with the applications of the implemented system. The case study has helped in developing a preliminary data model (i.e., a model about data by which a reasonable interpretation of the data can be obtained) for material handling (MH) functions.  相似文献   
84.
Rats dosed orally for four days with 0.24 g/kg body weight per day of brominated olive oil (BOO) or brominated sesame oil (BSO) were found to accumulate dibromostearic (DBS) acid (from BOO) and DBS and tetrabromosteric (TBS) acids (from BSO) in the liver, heart and adipose tissue. The metabolites, dibromopalmitic, and dibromomyristic acids (from BOO and BSO), as well as their tetrabromo-analogues (from BSO) were found as determined by gas chromatography with halogen specific detection and confirmed by gas chromatography-mass spectrometry. Blood contained no DBS, TBS or metabolites. However, inorganic bromide was observed in both blood and urine while none was observed in the feces. The latter contained significant quantities of both DBS and TBS but showed the absence of the four brominated metabolites.  相似文献   
85.
Present effort intends to improve the performance of gelatin based casted-films for controlled delivery of hydrophobic drugs. To achieve this goal, Piperine (a model drug) was loaded into gelatin (type A) casted-films by solvent evaporation method. Glutaraldehyde was used as a cross-linker for the gelatin films to modulate the drug release behavior and to prolong the rate of degradation of the film. In-vitro degradation study under physiological conditions and thermal analysis through differential scanning calorimetry were performed to confirm stability of the gelatin casted-film matrix. Aim was to control the drug release from films by varying the cross-linking degree and the gelatin concentration. Optical microscope analysis was performed to study the surface topography of the sample. In order to understand the drug–polymer interaction in the film, attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) analysis was done. The in-vitro release study gave an overall idea of the role of cross-linkers, gelatin concentration, and effect of pH on the release profiles of Piperine. Results show that one can effectively use gelatin casted-film based drug delivery systems for a wide range of release requirements, i.e., from fast release to delayed release.  相似文献   
86.
Journal of Materials Science: Materials in Electronics - A solution processed top-contact bottom-gated SnO2 thin-film transistor (TFT) has been fabricated using a TiO2/Li–Al2O3 bilayer...  相似文献   
87.
Geopolymer composites reinforced with refractory, chopped basalt fibers, and low melting glass were fabricated and heat treated at higher temperatures. K2O·Al2O3·4SiO2·11H2O was the stoichiometric composition of the potassium-based geopolymer which was produced from water glass (fumed silica, deionized water, potassium hydroxide), and metakaolin. Addition of low melting glass (Tm ~815°C) increased the flexure strength of the composites to ~5 MPa after heat treatment above 1000°C to 1200°C. A Weibull statistical analysis was performed exhibiting how the amorphous self-healing and self-glazing effect of the glass frit significantly improved the flexure strength of the geopolymer and ceramic composites after exposure for 1 hour to high temperatures. At 950-1000°C, the K-based geopolymer converted to primarily a crystalline leucite ceramic, but the basalt fiber remained intact, and the melted glass frit flowed out of the surface cracks and sealed them. 1150℃ was determined to be the optimum heat treatment temperature, as at ≤1200°C, the basalt fibers melt and the strength of the reinforcement in the composites is significantly reduced. The amorphous self-healing and amorphous self-glazing effects of the glass frit significantly improved the room temperature flexure strength of the heat-treated geopolymer and ceramic composites.  相似文献   
88.
In this paper, the performance improvement of a free space optical communication system with multi-hop and beam optimization has been studied. Novel closed-form expressions for the end-to-end average bit error rate, outage probability and average capacity of multi-hop free space communication system with decode-and-forward relaying are derived. Beam optimization is done using Nelder–Mead simplex algorithm. A composite channel model using atmospheric attenuation, turbulence and pointing errors is used to model the atmospheric impairments. The saturated atmospheric conditions are modeled by negative exponential channel model, and pointing error effects are considered by normalized jitter standard deviation parameter. The performance of the free space optical communication system in terms of end-to-end average bit error rate, outage probability and average channel capacity in saturated atmospheric turbulence conditions and pointing errors is significantly enhanced by using beam-optimized serial relaying with decode-and-forward transmission. The simulation results obtained by Monte Carlo simulation are in agreement with the results obtained from the closed-form expressions.  相似文献   
89.
Integer factorization is a vital number theoretic problem finding frequent use in public key cryptography, and other areas like Fourier transforms. There has been growing interest among researchers in innovative alternative approaches to solving the problem by modeling some optimizing natural or biological behaviour in a form of an algorithm that can be used to solve the problem provided the problem can be represented as an optimization task. In this paper, we present a new model based on computational chemistry behind how molecules interact among each other to minimize their surface energy potential in a typical crystal. While this phenomenon itself is a research problem, it interestingly provides a new way of solving other problems like integer factorization which can be represented in different forms of discrete optimization task. However, we must note that the present methods based on such models are not scalable to the real-world scenario, and we present a brief discussion on this issue.  相似文献   
90.
Computational Visual Media - Recently, learning-based models have enhanced the performance of single-image super-resolution (SISR). However, applying SISR successively to each video frame leads to...  相似文献   
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