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51.
    
In this contribution, we have utilized Jasmine flower (Tabernaemontana divaricata) extract as a green source during the synthesis of carbon under hydrothermal conditions. Phase characterization indicated that the prepared material is graphitic carbon with various functional groups. TEM images revealed that the prepared material is composed of quasi-spherical particles having diameters in the 15 nm range, which are accumulated in micro-spherical ones as indicated by SEM images. N2-adsorption measurements indicated that this spherical carbon possesses a mesoporous character. XPS data revealed the co-existence of various C, N, and O species at the surface of this carbon. Sodium borohydride (NaBH4) hydrolysis activity of the synthesized carbon was investigated over the 25–45 °C range of temperature. The catalytic activity was found to increase with both the temperature and NaBH4 concentration (up to 5 wt. %). Moreover, the activity was quenched in the presence of strong bases.  相似文献   
52.
    
The existence of the heterovalent metal states and S doping into Ce–Mo bimetallic oxide improve the photocatalytic activity by generating oxygen vacancy and narrowing the bandgap for suitable water splitting. Spherical and plate likes heterostructure Mo(S,O)/(Ce,Mo)(S,O) sulfo-oxide catalysts with heterovalent metal states and oxygen vacancy defects were synthesized by co-precipitation method for photocatalytic hydrogen evolution reaction. Catalyst labeled as 1-CeMoOS with more oxygen vacancies and high Ce3+/(Ce3++Ce4+) ratio evolved 405.18 μmol/h H2 and achieved AQE of 13.72%, whereas reduced 76.43% 4-NP and 91.52% RhB by in-situ generated protons. S doping, oxygen vacancy creation, Ce and Mo heterovalent states have narrowed the bandgap by substituting oxygen with sulfur, promoted the photogenerated charge carriers' effective separation, and prolonged the lifetime of electrons. The oxygen vacancy formation with a subsequently partial Ce4+-to-Ce3+ conversion achieves CeMoOS catalysts with excellent PHER and provides a promising way to improve photocatalysts' visible light PHER activity.  相似文献   
53.
    
Sector coupling will play a key role in the future energy system to realise greenhouse gas emission reductions. A major factor will be green hydrogen based on renewable energies to defossilise consumption sectors. Related business models of power to gas are not yet implemented on the market. However, given the urgency of the change, this is essential.This paper investigates hydrogen business models under current market conditions of high power prices, no existing market for green hydrogen and the given regulatory framework with no levies for green hydrogen production in the German market. For this purpose, an open-source business model evaluation tool for sector coupling, which enables a simple and generic evaluation of sector coupling business models including production and possible transportation infrastructure, is developed and applied. Furthermore, the impact of changes of the input parameters like power prices and the influence of regulatory changes on profitability are assessed.The results show that X-to-power business cases can be already profitable due to high power prices on the wholesale market. However, power-to-X business models like hydrogen production still have negative net present values and the net present value is worsened when infrastructure for hydrogen transportation is considered. Key parameters for the negative result are investment costs and low hydrogen prices. Nevertheless, it must be considered that higher hydrogen prices have a negative impact on the X-to-power business model. To allow for profitable business cases, the market conditions need to be adjusted to ensure sufficiently high prices for green hydrogen. Furthermore, subsidies on investment or operational and maintenance costs can support the integration of power-to-X into the market. Transportation infrastructure has a significant impact on profitability. Given these facts, it is necessary to create the required framework conditions to ensure the realisation of sector coupling.  相似文献   
54.
    
An optimum design and energy management of various distributed energy resources is investigated in a hybrid microgrid system with the examination of electrical, heating, and cooling demand. This paper suggested an optimal approach to design and operate a microgrid incorporating with battery energy storage, thermal energy storage, photovoltaic arrays, fuel cell, and boiler with minimization of the total operational cost of the hybrid microgrid. Two different hydrogen production methods are considered to assure the advantage of the developed proposed methodology. Furthermore, besides natural gas, residential and municipal wastes are collected and are utilized to produce electricity in fuel cell units. Load growth for different type of loads is also considered. The new number of households are added to the proposed system in different years and the proposed program is determined the optimum size of each employed resources to add each year for satisfying the total demand. To find out the optimum energy management and the optimum capacity of each employed distributed energy resources, a meta-heuristic Particle Swarm Optimization Algorithm is utilized. It is concluded from the results that by utilizing residential waste, the amount of natural gas consumption by fuel cells is reduced about 6.2%, and by utilizing residential plus municipal waste, the reduction is about 26.7%. It is also observed that the amount of CO2 emission is reduced significantly (46.8%) in the case of utilization of produced heat by fuel cells. Finally, the results confirmed the efficacy of the suggested optimal energy management of the hybrid microgrid.  相似文献   
55.
    
This study numerically simulates strain-rate dependent transverse tensile failure of unidirectional composites. The authors’ previous study reported that the failure mode depends on the strain rate, with an interface-failure-dominant mode at a relatively high strain rate and a matrix-failure-dominant mode at relatively low strain rate. The present study aims to demonstrate this failure-mode transition by a periodic unit-cell simulation containing 20 fibers located randomly in the matrix. An elasto-viscoplastic constitutive equation that involves continuum damage mechanics regarding yielding and cavitation-induced brittle failure is used for the matrix. A cohesive zone model is employed for the fiber–matrix interface, considering mixed-mode interfacial failure. For the results, the relationship between failure modes and the strain rate is consistent with the authors’ previous studies.  相似文献   
56.
    
《Zeolites》1994,14(8):650-659
Structures having a La3+ ion assigned to various sites in an idealized faujasite framework have been modeled using potentials developed from the study of oxides and successfully applied to zeolites. An initial structure is relaxed to minimum energy at constant pressure with all species free to move. The resulting lattice energy is used as a measure of the stability of the structure. On this basis, it is shown that distortion of the framework and the combined effect of many relatively long-range electrostatic interactions cause simple analyses based on high symmetry and short-range interactions to be unreliable. In particular, it is shown that the chance of an isolated La3+ ion's occupying an SI' site is comparable to that of its occupying an SI site, and, indeed, the SI' site can be the preferred location. This finding serves to clarify the interpretation of the X-ray diffraction data for single-crystal La-FAU. A further significant finding is that SII sites can be expected to have a higher population of La3+ ions in such structures than they have usually been thought to have.  相似文献   
57.
In 1952, Alan Turing published his last work on the concept of embryonic morphogenesis, propounding a computational framework for pattern formation within the developing embryo. This concept of morphogenesis and the concept of embryo pattern formation based on chemical diffusion patterns were corroborated with the discovery of the Homeobox or Hox genes. In the following decades, Hox gene research has expanded and is now shown to underlie the variety of morphological novelties that we experience in nature, the patterning of structural aspects of different organs including the brain and also mutant animals that may in the future give rise to novel speciation. Turing had the foresight and vision and with his work created the field of computational biology and mathematical modeling in biological systems. In this paper, we will discuss the concept of Hox genes, their role in patterning the embryo, how it relates to Turing’s concept of morphogenesis and what further insights they may provide.  相似文献   
58.
A retrospective radiologic study was performed to determine whether there is an increased finding of metatarsus proximus and digital divergence in patients with a confirmed diagnosis of intermetatarsal neuroma when compared with an asymptomatic group. The study included 48 patients with pathologic confirmation of neuroma and 100 asymptomatic patients. Results of the study revealed no statistical relationship between the radiologic findings of metatarsus proximus and digital divergence and the physical occurrence of neuromas. An unexpected finding was an increased intermetatarsal angle of the affected interspace in the neuroma group.  相似文献   
59.
The hydrological cycle for high latitude regions is inherently linked with the seasonal snowpack. Thus, accurately monitoring the snow depth and the associated aerial coverage are critical issues for monitoring the global climate system. Passive microwave satellite measurements provide an optimal means to monitor the snowpack over the arctic region. While the temporal evolution of snow extent can be observed globally from microwave radiometers, the determination of the corresponding snow depth is more difficult. A dynamic algorithm that accounts for the dependence of the microwave scattering on the snow grain size has been developed to estimate snow depth from Special Sensor Microwave/Imager (SSM/I) brightness temperatures and was validated over the U.S. Great Plains and Western Siberia.

The purpose of this study is to assess the dynamic algorithm performance over the entire high latitude (land) region by computing a snow depth multi-year field for the time period 1987–1995. This multi-year average is compared to the Global Soil Wetness Project-Phase2 (GSWP2) snow depth computed from several state-of-the-art land surface schemes and averaged over the same time period. The multi-year average obtained by the dynamic algorithm is in good agreement with the GSWP2 snow depth field (the correlation coefficient for January is 0.55). The static algorithm, which assumes a constant snow grain size in space and time does not correlate with the GSWP2 snow depth field (the correlation coefficient with GSWP2 data for January is − 0.03), but exhibits a very high anti-correlation with the NCEP average January air temperature field (correlation coefficient − 0.77), the deepest satellite snow pack being located in the coldest regions, where the snow grain size may be significantly larger than the average value used in the static algorithm. The dynamic algorithm performs better over Eurasia (with a correlation coefficient with GSWP2 snow depth equal to 0.65) than over North America (where the correlation coefficient decreases to 0.29).  相似文献   

60.
OBJECTIVE: The state psychiatric hospital is experiencing an increase in medically sick and aging patients who die of natural causes while hospitalized. This study explored the "medicalization" of the state hospital by examining the prevalence of medical illness and its relationship with psychiatric illness and age among state hospital psychiatric inpatients who died of natural causes--deaths that were not accidents, homicides, or suicides. METHODS: A total of 179 inpatients who died of natural causes at Western State Hospital in Washington State between 1989 and 1994 were studied retrospectively through case file review. Their demographic and institutional characteristics and psychiatric diagnoses were compared with those of others treated at the hospital (N=9,258). The medical diagnoses of patients who died were analyzed by age and psychiatric condition. RESULTS: The patients who died were much older than the other patients treated during the study period. Two-thirds of those who died had organic mental disorders, mostly dementia, whereas only a fifth of the other patients had these disorders. The patients who died had a mean of eight physical illnesses, with a range from none to 21. Circulatory and respiratory conditions were most prevalent, affecting half to two-thirds of patients; these conditions had high rates of comorbidity with organic mental disorders. CONCLUSIONS: The characteristics of the state hospital population and the services provided are shifting in response to mental health reform and new policies on patient self-determination. Increased emphasis on medical care added to traditional psychiatric services will require increased financial and personnel resources.  相似文献   
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