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1.
Abstract

Cell exposure experiments at the air-liquid interface (ALI) are used increasingly as indicators for health effects and for the impact of aerosols on the lung. Thereby the aerosol particles are kept airborne and can deposit on a cell surface area similar to the human respiratory tract (RT). However, geometry and air flow rates of an ALI system deviate considerably from the RT. As the tissue-delivered particle dose to the lungs (TD) can hardly be measured, computer models of particle deposition are used here to mimic both the particle deposition at ALI and in the RT. An ALI exposure setup (VitroCell GmbH) for an airflow rate of 100 cm3 min?1 is selected, where the particle deposition model has been verified experimentally. For the RT we use the hygroscopic lung deposition model of Ferron et al. (2013 Ferron, G. A., S. Upadhyay, R. Zimmermann, and E. Karg. 2013. Model of the deposition of aerosol particles in the respiratory tract of the rat. II. Hygroscopic particle deposition. J. Aerosol Med. Pulm. Drug Deliv. 26 (2):10119. doi:10.1089/jamp.2011.0965.[Crossref], [PubMed], [Web of Science ®] [Google Scholar]). Model runs are performed for the particle deposition and for the deposited particles per surface area in both the ALI and the RT. The results show that the ALI-deposited mass is 1-2 orders of magnitude higher than in the alveolar region, because the surface area of the lung region is substantially larger. A particle size range from 40 to 450 nm is identified, where the ratio of both the deposition in a lung region and the deposition at the ALI varies by a factor less than two. Mean values for this ratio are 31 and 101 for the tracheo-bronchial and the alveolar region, respectively. The same size range is found for the ratio of the deposited particles per surface area in a lung region and at the ALI. For this range the mean surface deposition at the ALI is 23- and 1575-times larger than in the tracheo-bronchial and the alveolar lung region, respectively. The effect is partly compensated by different flow rate and cell size.

Copyright © 2020 American Association for Aerosol Research  相似文献   
2.
为更有针对性地进行故障排除工作,文章设计研发了一款多媒体软件平台,嵌入细化后的DZZ5型自动气象站各观测要素的故障排查流程,并在相应故障检测节点中添加文字、图片和操作视频。用户可按照流程逐一进行排查操作,或者搜索关键字查看节点内容。同时提供带有关键字查询功能的故障实例库,供基层装备保障业务人员参考。  相似文献   
3.
In this communication, N-doped multiwall carbon nanotube (N-MWCNT) supported Pt NPs (1.8 nm) were prepared via a facile routine under microwave irradiation and tested in the selective oxidation of glycerol in an aqueous base-free solution. Characterizations confirmed that N-MWCNTs could improve the dispersion of Pt through strengthened metal-support interactions and donate its electron to metallic Pt. This electron-enriched Pt NPs on the surface of N-MWCNTs is active and stable for the selective oxidation of glycerol.  相似文献   
4.
With the growing use of renewable energy sources, Distributed Generation (DG) systems are rapidly spreading. Embedding DG to the distribution network may be costly due to the grid reinforcements and control adjustments required in order to maintain the electrical network reliability. Deterministic load flow calculations are usually employed to assess the allowed DG penetration in a distribution network in order to ensure that current or voltage limits are not exceeded. However, these calculations may overlook the risk of limit violations due to uncertainties in the operating conditions of the networks. To overcome this limitation, related to both injection and demand profiles, the present paper addresses the problem of DG penetration with a Monte Carlo technique that accounts for the intrinsic variability of electric power consumption. The power absorbed by each load of a medium voltage network is characterized by a load variation curve; a probabilistic load flow is then used for computing the maximum DG power that can be connected to each bus without determining a violation of electric constraints. A distribution network is studied and a comparison is provided between the results of the deterministic load flow and probabilistic load flow analyses.  相似文献   
5.
The CA-TIMES optimization model of the California Energy System (v1.5) is used to understand how California can meet the 2050 targets for greenhouse gas (GHG) emissions (80% below 1990 levels). This model represents energy supply and demand sectors in California and simulates the technology and resource requirements needed to meet projected energy service demands. The model includes assumptions on policy constraints, as well as technology and resource costs and availability. Multiple scenarios are developed to analyze the changes and investments in low-carbon electricity generation, alternative fuels and advanced vehicles in transportation, resource utilization, and efficiency improvements across many sectors. Results show that major energy transformations are needed but that achieving the 80% reduction goal for California is possible at reasonable average carbon reduction cost ($9 to $124/tonne CO2e at 4% discount rate) relative to a baseline scenario. Availability of low-carbon resources such as nuclear power, carbon capture and sequestration (CCS), biofuels, wind and solar generation, and demand reduction all serve to lower the mitigation costs, but CCS is a key technology for achieving the lowest mitigation costs.  相似文献   
6.
为解决无水文资料地区水文计算的难题,科学客观地选择参证流域,针对4种参证流域选择的定量分析法:灰色分析法、模糊分析法、投影寻踪法和集对分析法,结合实际案例,探讨了其实质、特点及其优缺点。结果表明:4种方法的原理和处理手段存在差异,因其具有统一的客观评价基础,最终结果是一致的,因此4种方法具有普遍适用性,在实际工作中,使用者可根据资料条件和爱好选择使用。  相似文献   
7.
能见度仪校准系统作为能见度校准的标准器,其不确定度直接影响到前向散射式能见度仪的校准结果。介绍了国家级能见度仪校准实验室的能见度仪校准系统的组成和校准方法,分析了校准系统不确定度的主要来源,依据国家计量校准规范JJF 1059.1-2012《测量不确定度评定与表示》,利用能见度测量数据,对校准系统A类和B类不确定度进行了评定分析,并对3台前向散射式能见度仪进行了校准试验。结果显示,整个校准系统在能见度3 000 m以下,扩展不确定度为5.8%,校准后的3台前向散射式能见度仪在100、500、1 000、1 500、2 000、3 000 m六个测试点的相对误差,最大为7.8%,最小为1.8%,满足能见度仪校准和实际观测要求。  相似文献   
8.
A recent electricity price forecasting study has shown that the Seasonal Component AutoRegressive (SCAR) modeling framework, which consists of decomposing a series of spot prices into a trend-seasonal and a stochastic component, modeling them independently and then combining their forecasts, can yield more accurate point predictions than an approach in which the same autoregressive model is calibrated to the prices themselves. Here, we show that further accuracy gains can be achieved when the explanatory variables (load forecasts) are deseasonalized as well. More importantly, considering a novel extension of the SCAR concept to probabilistic forecasting and applying two methods of combining predictive distributions, we find that (i) SCAR-type models nearly always significantly outperform the autoregressive benchmark but are in turn outperformed by combined SCAR forecasts, (ii) predictive distributions computed using Quantile Regression Averaging (QRA) outperform those obtained from historical simulation and bootstrap methods, and (iii) averaging over predictive distributions generally yields better probabilistic forecasts of electricity spot prices than averaging over quantiles. Given that probabilistic forecasting is a concept closely related to risk management, our study has important implications for risk officers and portfolio managers in the power sector.  相似文献   
9.
Dynamical downscaling attempts to provide regional detail to climate change projections that subsequently can be used as input to climate change impact models. However, unlike forecasts by numerical weather prediction models, downscaled projections cannot be tested for skill because the future of interest is decades away. Nevertheless, models can be tested in terms of how well they simulate current weather or climate, thus giving an indication of skill in representing the process of interest. Here, six configurations using different combinations of three microphysics and two planetary boundary layer schemes are assessed on their skill to simulate desired characteristics in daily rainfall fields from three two week simulations in southeast Australia; ‘desired’ meaning desirable in relation to the intended application. Of different metrics and analysis assessed, a metric based on variography analysis, summarising characteristics about spatial variability and dissimilarity, is shown to provide the most informative guidance relative to the desirable characteristics.  相似文献   
10.
根据我国气象装备供应保障现状及综合观测网业务需求,在现有的气象装备物流基础上研究探讨适合我国气象装备供应保障业务发展需求的气象技术装备物流体系。依靠全国气象部门现有成熟的业务流程及库房基础,建设现代化气象装备物流中心;应用现阶段先进的自动化分拣技术建设自动化立体库房;同时建设气象装备供应信息化管理系统。通过这些技术手段建立起适应我国综合气象观测网探测技术发展的、具有现代信息化管理水平的气象技术装备保障物流体系。  相似文献   
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