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排序方式: 共有170条查询结果,搜索用时 609 毫秒
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Sustainability evaluation framework for building cooling systems: a comparative study of snow storage and conventional chiller systems 总被引:1,自引:0,他引:1
Venkatesh Kumar Kasun Hewage Husnain Haider Rehan Sadiq 《Clean Technologies and Environmental Policy》2017,19(1):137-155
In Canada, the residential building sector consumes 17 % of the total energy and 15 % of the total greenhouse gas emissions. In particular, the energy demand for cooling in the residential sector is increasing due to the large occupancy floor area and high usage of air conditioning. Minimizing energy use and greenhouse gas emissions is one of the highest priority goals set for national energy management strategies in developed countries including Canada. In this study, a framework based on the life cycle assessment approach is developed to assess the environmental impacts of different building cooling systems, namely conventional snow storage system, watertight snow storage system, high-density snow storage system, and the conventional chiller cooling system. Moreover, all these systems have varying energy requirements and associated environmental impacts during different phases (extraction and construction, utilization, and end of life) of the life cycle of a building. A low-rise residential building in Kelowna (BC, Canada) has been selected for the pragmatic application of the proposed framework. The annual cooling energy demand for the building is estimated for different phases. Subsequently, the life cycle impact assessment has been carried out using SimaPro 8.1 software and TRACI 2.1 method. For sustainability evaluation of different cooling systems over their life cycle, multi-criteria decision analysis has been employed using the ‘Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE II).’ The results showed that the snow storage systems tend to reduce greenhouse gas emissions and associated environmental impacts more than the conventional system. 相似文献
3.
Reliability analysis of TLP tethers under impulsive loading 总被引:1,自引:0,他引:1
R.A. Khan N.A. Siddiqui S.Q.A. Naqvi S. Ahmad 《Reliability Engineering & System Safety》2006,91(1):73-83
In the present study, reliability assessment of Tension Leg Platform (TLP) tethers against maximum tension (i.e. tension exceeding yield) has been carried out under combined action of extreme wave and impulsive forces. For this purpose, a nonlinear dynamic analysis of TLP has been carried out in time domain. A limit state function for maximum tension (i.e. tension exceeding yield) has been derived employing Von-Mises theory of failure. Using this derived limit state function and responses obtained after dynamic analysis under sinusoidal, half-triangular and triangular impulsive forces, reliability assessment of the TLP tethers has been carried out. Design point, important for probabilistic design of tethers, has been located on the failure surface after solving a constrained optimization problem. To study the influence of various random variables on tether reliability, sensitivity analysis has been carried out. Effects of angle of impact; effect of variable submergence; and effect of material yield strength on tether reliability have also been studied on parametric basis. Effect of uncertainty on overall tether reliability has also been discussed to show the importance of quality control in the various design parameters. 相似文献
4.
Asif Hussain Khoja Arslan Mazhar Faisal Saleem Muhammad Taqi Mehran Salman Raza Naqvi Mustafa Anwar Sehar Shakir Nor Aishah Saidina Amin Muhammad Bilal Sajid 《International Journal of Hydrogen Energy》2021,46(29):15367-15388
The catalyst has a significant role in gas processing applications such as reforming technologies for H2 and syngas production. The stable catalyst is requisite for any industrial catalysis application to make it commercially viable. Several methods are employed to synthesize the catalysts. However, there is still a challenge to achieve a controlled morphology and pure catalyst which majorly influences the catalytic activity in reforming applications. The conventional methods are expansive, and the removal of the impurities are major challenges. Nevertheless, it is not straightforward to achieve the desired structure and stability. Therefore, significant interest has been developed on the advanced techniques to take control of the physicochemical properties of the catalyst through non-thermal plasma (NTP) techniques. In this review, the systematic evolution of the catalyst synthesis using NTP technique is elucidated. The emerging DBD plasma to synthesized and effective surface treatment is reviewed. DBD plasma synthesized catalyst performance in reforming application for H2 and syngas production is summarised. Furthermore, the status of DBD plasma for catalyst synthesis and proposed future avenues to design environmentally suitable and cost-effective synthesis techniques are discussed. 相似文献
5.
Benzyl chloride has been used in a kinetic study of chlorine replacement by acetoxy groups to model the behaviour of allylic chlorine during the acetoxylation of poly(vinyl chloride). Chlorine substitution was carried out in tetrahydrofuran at 30°C using a potassium acetate-crown ether complex with methanol to ensure homogeneous solution. The process followed an SN2 mechanism. The orders of reaction with respect to benzyl chloride and potassium acetate were close to one, and the second order velocity constant was 4.2 x 10?5 litre mol?1 s?1 when the molar ratio of crown ether to potassium acetate was approximately unity. Higher ratios caused a slight increase in rate constant. Substitution was followed by NMR spectroscopy which also revealed a proton exchange between methanol and acetate anion with an equilibrium constant 9.4 x 10?2. This observation has suggested an explanation for the effect of some free-radical inhibitors on the rate of acetoxylation of poly(vinyl chloride) by potassium acetate in the presence of crown ether. 相似文献
6.
Fehmida Naqvi Abdul Rauf M. M. Siddiqui M. S. Ahmad Jr. S. M. Osman 《Journal of the American Oil Chemists' Society》1997,74(6):713-717
Pseudohalogenation of methyl 9-hydroxy-cis-12-octadecenoate (I) and methyl 12-hydroxy-cis-9-octadecenoate (II) has been carried out with N,N-dibromobenzenesulfonamide (NNDBS). Compounds I and II, on reaction with NNDBS, formed four and three products, respectively. The interesting feature of these reactions was the
formation of 1,4-epoxy compounds. The structures of individual compounds were established with the help of elemental and spectral
analysis. 相似文献
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A new medium access protocol which exploits the physical layer capability of multiuser detection is proposed to help in improving
the throughput/delay performance of ad-hoc networks. When more than one node has packets buffered for a common node in the
neighborhood, all such nodes can simultaneously transmit their packets to the common receiver after reserving their surrounding
channel. This is achieved in our protocol by extending the (sender-initiated) CSMA/CA collision avoidance framework by the
receiver-initiated medium access technique and incorporating the transmission power control. We analyze the improvement in
the throughput that can be achieved over the basic sender-initiated collision avoidance protocol in the network. Since the
throughput improvement via multi-packet reception is influenced by the network layer activity as well, the performance of
our protocol rolls back to that of the basic sender-initiated protocol in case of no coordination from the network layer.
For the evaluation of performance of our protocol we simulate ad-hoc networks for different network topologies and traffic
configurations. We observe the scheme to be capable in significantly improving the throughput/delay performance of the network. 相似文献
9.
In this paper new algorithms for the rapid, efficient and accurate evaluation of the standard normal integral and its tail are developed. It is shown how the accuracy of the computation can easily be improved so as to achieve machine accuracy for the particular computer being used. 相似文献
10.