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81.
A procedure was developed to accurately measure the W isotopic compositions of iron meteorites with a precision of better than +/-0.1 epsilon on epsilon182W and epsilon184W (normalized to 186W/183W). Purification of W was achieved through a two-step, ion-exchange procedure. In most cases, the yield is better than 80%, and purified W solutions are clear of matrix elements and direct isobars of W. The final W solutions were analyzed using a Micromass Isoprobe multicollector inductively coupled plasma mass spectrometer (MC-ICPMS). Tests performed on mixtures of terrestrial standards and meteorite samples demonstrate that the method is accurate and that epsilon182W variations as small as approximately 0.1 epsilon can be detected. Analyses of three different aliquots of the Gibeon (IVA) iron meteorite obtained over a period of 6 months show identical epsilon182W values with a weighted mean of 3.38 +/- 0.05, consistent with literature data for IVA iron meteorites, and indicating that the metal-silicate differentiation event in its parent body was either contemporaneous with or slightly postdated (by up to approximately 2.5 My) the formation of refractory inclusions. We demonstrate our ability to measure epsilon184W accurately and precisely (within +/-0.1 epsilon), which is useful for characterizing cosmogenic and nucleosynthetic effects that may be present in iron meteorites. We also report for the first time measurements of epsilon180W, albeit with large error bars (<+/-4 epsilon, in most cases).  相似文献   
82.
The health benefits of phenolic antioxidants justify their inclusion in foods like deep-fried potato fritters that are exposed to high heat during processing. In this study, phenolic antioxidants [quercetin, rutin or an apple phenolic extract (APE)] were incorporated into batters that were subsequently used in the preparation of deep-fried potato fritters. The fritters were deep fried at 180 °C for 2.5 min or 165 °C for 3 min using fresh or used canola oil. The study aimed to investigate the effect of added phenolic antioxidants on the lipid deterioration during deep frying potato fritters. The effectiveness of these phenolics against lipid deterioration was also examined for the potato fritters that have been left in the air at room temperature for 0.5 or 1 h after deep frying. The total oxidation (Totox) value (based on the peroxide value and p-anisidine value) and free fatty acid content of the oil extracted from the deep-fried potato fritters, as well as the total extractable phenolic content, of the fritters were evaluated. Results showed that APE, quercetin and rutin suppressed oil deterioration to different extents, and their effectiveness was influenced by deep-frying conditions, the number of times the oil had been used and the time period that the fritter was exposed to the air after deep frying. For the fresh or singly used oil, the recommended deep-frying parameters are 180 °C for 2.5 min (“high heat short time” approach). For oil used more than once, deep frying of potato fritters at 165 °C for 3 min (“low heat long time” approach) is generally recommended. Adding phenolics to the batter used for making potato fritters before deep frying increases product nutritional value and reduces oil oxidation, which indicates the feasibility of producing healthier potato fritters.  相似文献   
83.
BACKGROUND: A criticism of conventional office or clinic-based models of care is that they focus on patients' urgent problems and do not provide the comprehensive assessments, education, and psychosocial support that vulnerable patients also need. Innovative models have emerged to address these needs. A systematic review of prospective studies involving searches of computerized databases, reviews of reference lists, and contacts with authors, was conducted to determine whether multidisciplinary teams, outreach or home care, and case management improve the quality of the care in two vulnerable populations-the terminally ill and the mentally ill. RESULTS: Literature searches identified 730 citations. 52 original articles met screening standards, and 24 studies fulfilled all criteria. Patient and caregiver satisfaction was consistently higher with innovative models. In no study was satisfaction lower. Functional, clinical, or psychological improvements were not consistently demonstrated. For mentally ill patients, multidisciplinary outreach strategies were effective in reducing inpatient hospitalizations. Costs were inadequately assessed in the studies to draw a summary conclusion. DISCUSSION: Like other interventions, health care delivery models can be assessed from an evidence-based perspective. More needs to be learned about the costs and health improvements of innovative models before we can determine whether the increased patient and caregiver satisfaction found justifies widespread use of these models. Development of a uniform set of quality outcome measures and encouragement to evaluate efforts and disseminate results will help accomplish this goal.  相似文献   
84.
In this paper, three objectives of Multiobjective Optimal Load Flow (MOLF) problem — cost of generation, system transmission loss and pollution — are considered. The MOLF problem is formulated as a multiobjective optimization problem using weighting method and a number of noninferior solutions are generated in 3D space. The optimal power system operation is attained by Ideal Distance Minimization method. This method employs the concept of an ‘Ideal Point’ (IP) to scalarize the problems having multiple objectives and it minimizes the Euclidean distance between IP and the set of noninferior solutions. This method has been applied to three IEEE standard systems.  相似文献   
85.
Practitioners and academicians throughout the world recognize the crucial role played by flexibility within manufacturing organizations, especially those engaged in small batch manufacture. However, although the concept of flexibility has begun to attract increased attention, its interaction with information integration and automation has not captured due attention. For example, it almost always has been assumed that a real-time control mechanism is available for exploiting routing flexibility on the shop floor. While this may be true for FMSs, it generally is not so for the vast majority of conventional manufacturing systems with varying levels of information integration and automation. The lack of a fully integrated and automated control mechanism within such semi-automated flexible manufacturing systems (SAFMSs) would eventually cause delays in the availability of shop status information. In this paper, we study the impact that defined modes of information delay have on the performance of a hypothetical SAFMS through detailed simulation experiments. Given that the level of routing flexibility is a controllable design parameter, our interest is in determining the impact that information delays have on decisions pertaining to the selection of appropriate levels of routing flexibility. To highlight the impact of information delays within the SAFMS, the Taguchi experimental design procedure is adopted as a performance evaluation and analysis vehicle, using makespan as a measure of performance. Simulation results indicate the presence of a system specific tolerance limit, operation below which minimizes performance loss.  相似文献   
86.
Microsystem Technologies - This work addresses a novel biosensor design and its surface potential sensitivity analysis to identify various biomolecules. The designed structure integrates the...  相似文献   
87.
Functional foods, with their synergistic health benefits that go beyond just being a source of individual nutrients, present challenges to the traditional ‘nutrition’ view of foods. Consumers demand proven health benefits without compromising flavour, taste and colour. A successful functional food must offer nutrients, specific health-promoting functionality and desirable sensory attributes. Attempts to increase the intake of desirable bioactive compounds are driven by the need to deliver optimal bioactivity to consumers for disease prevention and health enhancement. Increasing the bioactive concentration in foods often leads to bitterness, particularly when incorporating bioactive phytochemicals. This article provides an overview of the strategies which can be used for food bitterness reduction, with an emphasis on those approaches which are industrially relevant and economically feasible, i.e. tailored food formulation, processing and delivery technology approaches. Solutions for reducing bitterness from phytochemicals in food are proposed, including blocking, inhibiting, suppressing, minimising and masking mechanisms. The potential of encapsulation and non-encapsulation approaches for functional food applications is highlighted, and their effect in improving stability, bioactivity, bioaccessibility and bioavailability is addressed.  相似文献   
88.
This research explores the spray-drying microencapsulation of polyphenols (PPs), quercetin and vanillin, using four different fibre polymers as encapsulants (sodium alginate, methyl β-cyclodextrin (MβCD), hydroxypropylmethyl cellulose (HPMC) and inulin). The microstructure, physico-chemical properties, PP content and reconstitution properties in water of the spray-dried powders were systematically evaluated and compared. Techniques used for powder characterisation were scanning electron microscopy, N2 physisorption, Fourier transform infrared (FT-IR) spectroscopy and water activity measurements. High-performance liquid chromatography and viscosity measurements were used to characterise the solutions obtained by reconstitution of the spray-dried powders in methanol or water, respectively. Results show that the type of encapsulant strongly influenced powder morphology, powder surface area and encapsulation efficiency of PPs. Powders prepared using sodium alginate and MβCD possessed more spherical particle shape, smaller average particle size and higher specific surface area than those using HPMC or inulin as encapsulants. For each encapsulant, higher encapsulation efficiencies were achieved for vanillin (37–53 %) than quercetin (9–19 %). Encapsulation efficiencies were inulin?>?MβCD?>?HPMC?>?sodium alginate for vanillin-containing powders. Inulin, MβCD and sodium alginate all gave similar encapsulation efficiencies for quercetin-containing powders. All powders possessed low water activity and excellent dissolution properties in water. Therefore, spray-drying microencapsulation using natural fibre encapsulants is a feasible approach for delivering the dual health benefits of PPs and dietary fibre to consumers. Spray-drying yields a product in a convenient powder form, which can be reconstituted in water or other beverages for direct consumption or used as a functional additive in solid food systems.  相似文献   
89.
Adding polyphenols (PPs) to yoghurt is a convenient way to deliver the health benefits of PPs and also the probiotic effects of starter cultures. In this study, drinking yoghurts with apple PPs (chlorogenic acid, phlorizin, or apple PP extract (APE)) added pre- or post-fermentation, and pectins (low or high methoxyl) were subjected to chemical, physical, and microbiological analyses. Results show that the type of PPs and pectin affected the total extractable PP content (TEPC), PP profiles, viscosity, storage modulus of yogurt, colony number, and morphology of the starter cultures. Adding APE before fermentation produced yoghurts with a greater TEPC and more polar PPs than adding post-fermentation. Producing drinking yoghurt enhanced with apple PPs via either approach is feasible. The pre-fermentation approach may be more beneficial in terms of increased TEPC and growth of starter culture, offering a bio-process to optimise PP profiles in drinking yoghurt.  相似文献   
90.
This study measures and compares the bioactive content and appearance attributes of juices, dietary fibres (DFs) and skin wastes of three apple genotypes (white fleshed (WF), pink fleshed (PF) and red fleshed (RF)). The juices of the PF and RF apples had more appealing and stable colours and much greater total extractable polyphenol content (TEPC) (RF had the highest, 3.40 mg catechin equivalent/mL juice) and vitamin C (PF had the highest, 14.2 mg/100 mL juice), compared with the WF apple. DFs isolated from the three apples using aqueous and ethanolic methods varied in bioactive profiles as a function of genotype. The TEPC and antioxidant activity (AA) of the fibres decreased in the order of PF > RF > WF. The total DF (TDF) in the fibre obtained using the aqueous method decreased in the order of RF?>?PF?>?WF. The ethanolic method yielded higher neutral monosaccharide (NM) and slightly greater TDF contents than the aqueous method. More polyphenol species were detected in the PF fibres, especially those obtained using the aqueous method. The polyphenol content in the apple skin decreased in the order of RF > WF > PF, with PF having slightly more pectic polysaccharides. As a whole, the RF apple appeared to be the best genotype as the potential source for juice, fibre and skin waste extract (SWE) ingredients. The PF apple would be the second best genotype for juice and fibre ingredients. The skin of the RF and WF genotypes would provide a good source of polyphenols. There is potential for promoting RF and PF apple genotypes because of their excellent nutritional values. The aqueous fibre preparation method used herein containing no solvent treatment and freezing steps represents an industrial-scale cost-effective alternative to the conventional ethanolic methods used for producing DFs whilst retaining polyphenols.  相似文献   
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