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排序方式: 共有161条查询结果,搜索用时 171 毫秒
81.
Traditionally, state-encoding strategies targeting minimization of area, dynamic power or a combination of them have been utilized in finite state machine (FSM) synthesis. With drastic scaling down of devices at recent technology level, leakage power has also become an important design parameter to be considered during synthesis. A genetic algorithm-based state encoding, targeting area and power minimized FSM, has been proposed in this paper. A unified technique to reduce both static power (leakage) and dynamic power along with area trade-off has been carried out for FSM synthesis, targeting static CMOS NAND-NAND PLA, dynamic CMOS NOR-NOR PLA and pseudo-NMOS NOR-NOR PLA implementations. Suitable weights for area, leakage power and dynamic power to minimize power density have also been explored. Simulation with MCNC benchmarks shows an average improvement of 31%, 26% and 29% in leakage power consumption, dynamic power consumption and area requirement respectively, over NOVA-based state assignment technique in case of dynamic CMOS PLA implementation. Improvements of 30% in leakage power and 15% in area have been obtained for pseudo-NMOS PLA implementation. For the static CMOS case, the improvements are about 29% in leakage power consumption, 14% in dynamic power consumption and 18% in area requirement.  相似文献   
82.
This paper summarizes field-testing of eight decked bulb-tee girder bridges as well as development of three-dimensional finite-element (FE) models. Using the calibrated 3D FE models, parametric studies have been performed to study the effect of shear connectors and intermediate diaphragms on live-load distribution and connector forces. It was found that: (1) in all cases studied, the live- load distribution factor (DF) for a single-lane loaded bridge was smaller than one for a double-lane loaded bridge; (2) connector forces caused by wheel loads were not uniform along the longitudinal joint—adding intermediate diaphragms tended to reduce the difference among horizontal shear forces in connectors; (3) the maximum horizontal shear force increased with the increase of the connector spacing—intermediate diaphragms reduced the maximum horizontal shear force in connectors; (4) the maximum vertical shear force and in-plane normal tensile force in connectors do not necessarily increase with the increase of the connector spacing; and (5) the summation of connector forces in each direction along the longitudinal joint remained constant irrespective of the number of connectors in the joint.  相似文献   
83.
The environmental scanning electron microscope has been used to image the adhesive pads secreted by zoospores of the marine alga Ulva linza as they settle on a range of self-assembled and grafted monolayers of different wettability, under natural, hydrated conditions. Results reveal that the diameter of the adhesive pad is strongly influenced by surface wettability, the adhesive spreading more (i.e. wetting the surface better) on the more hydrophilic surfaces. This is in direct contrast to previous observations on the spreading of marine bioadhesives and is in apparent contradiction to the predictions of the Young-Dupre equation for three-phase systems. In this paper, we attempt an explanation based upon thermodynamic analysis of the wetting properties of hydrophilic proteins.  相似文献   
84.
Effects of rapid heat transfer using a fluidized bed on the heat-treating response of Al–Si–Mg alloys (both unmodified and Sr modified) were investigated. Heating rate in fluidized bed (FB) is an order of magnitude greater than in conventional air convective furnaces (CF). On aging using FB, it was observed that the nucleation rate of Mg2Si particles was greater than in CF. Thermal analyses show an endothermic reaction during aging in CF. No such transformation was observed during aging in FB. The endothermic transformation could be due to the dissolution of GP zones or metastable phase(s). The total heat treatment time for T6 temper was reduced to less than 2 h using FB.  相似文献   
85.
Hybrid Ceramic Matrix/Metal Matrix Composite Gun Barrels   总被引:1,自引:0,他引:1  
Future Army gun systems will require lighter weight and significantly more erosion-resistant materials. One route to achieve this goal is via the development of ceramic matrix composite barrel liners with lightweight metal matrix composite jackets. Such materials systems are hybrids of a ceramic matrix composite/metal matrix composite (CMC/MMC), which can provide functionally graded properties. This paper will describe the materials system development, fabrication, and property validation testing of such a hybrid CMC/MMC for a 25-mm-bore, 915-mm-long, rifled barrel.  相似文献   
86.
The 3GPP proposal for IMT-2000   总被引:7,自引:0,他引:7  
Market expectations for third-generation mobile radio systems (IMT-2000) show an increasing demand for a wide range of services from voice to low, high, and advanced data rate services to support mobile multimedia. This leads to technical requirements for IMT-2000 which are currently being standardized worldwide. Circuit- and packet-oriented services will be supported. These systems will operate in all radio environments to provide service to anyone, anytime, anywhere. The ITU has identified spectrum for the allocation of IMT-2000. However, these frequency bands are currently not available worldwide. In different regions research activities on IMT-2000 have been initiated to support the international consensus building process and standardization activities. Based on these activities system proposals have been submitted to ITU TG 8/1. In particular, the newly formed Third Generation Partnership Projects 3GPP and 3GPP2 have the objective of harmonizing similar proposals and defining detailed standards. Proposals from Europe, Japan, Korea, and the United States are very similar. The evolution and migration of second-generation systems to the third generation takes into account the deployed investment to save today's investment where useful and necessary. This article focuses on market and technical requirements and, in particular, the technical approach of 3GPP based on the big footprint of the GSM system  相似文献   
87.
Plastic scintillation detectors based whole bodyβ/γcontamination monitors are developed for use in radi-ation facilities. This microcontroller-based multi-detec...  相似文献   
88.
This is a comparative study examining the influence of a small-scale dementia unit and a traditional dementia unit on behaviors of the residents. The small-scale unit and the traditional unit were selected through two phases in Vancouver, Canada. Seven residents from each facility completed the study. Physical environmental assessments were performed using two tools: PEAP (professional environmental assessment protocol) and TESS-NH (therapeutic environment screening survey for nursing homes). For the assessment of residents' behaviors, three assessment tools were used: MOSES (multidimensional observation scale for elderly subjects), MDS (minimum data set) and DCM (dementia care mapping). The study found that the residents living in a small-scale environment were more engaged in activities and more likely to respond in understanding their fellow residents. Residents living in a traditional long-term care exhibited fewer signs of social interaction. The findings suggest that a small-scale homelike environment could positively influence people with dementia to be more engaged in social exchanges and activities, and consequently help in reducing their withdrawn behavior.  相似文献   
89.
The effect of ammonium phosphate on the growth, lipid content, and γ-linolenic acid accumulation was determined in the cyanobacterium Spirulina platensis. After 14 d on media containing 0.041 g N/L, γ-linolenic acid concentration of cultured cells increased up to 35.3±0.13%, w/w. In treatments containing NaNO3, NH4NO3, and NH4Cl, γ-linolenic acid concentration increased up to 31.2±0.23%, w/w. After the same period, lipid content in the dry biomass was 12.2±0.03%, w/w, with (NH4)2HPO4 compared to about 14.1±0.12%, w/w, in treatments with NaNO3. When (NH4)2HPO4 concentration in the medium was increased to 0.082 g N/L, 30.8±0.28%, w/w, γ-linolenic acid had formed after 10 d and the lipid percentage in the dry cell mass was 16.7±0.16%, w/w. However, in treatments with NaNO3, NH4NO3, or NH4Cl, γ-linolenic acid concentration increased up to 30.6±0.23%, w/w, and the lipid content was found to be 18.0±0.17 to 18.9±0.03%, w/w. These data showed that (NH4)2HPO4 is a suitable source of nitrogen for growth of S. platensis, with increased accumulation of γ-linolenic acid at lower N concentration.  相似文献   
90.
Leaching studies using spent petroleum catalyst containing Ni, V and Mo were carried out using two different acidophiles, iron oxidizing (IOB) and sulfur oxidizing (SOB) bacteria. XRD analysis proved the existence of V in oxide form, Ni in sulfide form, Mo both in oxide and sulfide forms, and sulfur in elemental state. Both bacteria showed similar leaching kinetics at the same leaching parameters, such as pH, nutrient concentration, pulp density, particle size and temperature. The dissolution kinetics for Ni and V was much higher than Mo. Bioleaching kinetics was observed to follow dual rates, initially faster followed by a slower rate. So, dissolution mechanism was based on surface- and pore-diffusion rate. The dissolution process was found to follow 1st order kinetics. Unified dissolution rate kinetics equations were developed using 1st order rate kinetics. Various thermodynamic parameters were also calculated. Rate determining step for both the bacteria were evaluated and the average D1 (surface) and D2 (pore) values were found to be around 7 × 10− 9 and 1 × 10− 10 cm2 respectively. The lower value of D2 suggested that the pore diffusion is the rate determining step during bioleaching process.  相似文献   
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