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排序方式: 共有48条查询结果,搜索用时 15 毫秒
1.
排列互比法用于超精测角的研究   总被引:3,自引:0,他引:3  
作者分析了我互比法现行的两种数据处理方法的缺点,提出了应用最小二乘法原理推导出合理的数据处理方法。本文还首次从理论上阐明了排列互比法测量结果中出现一次谐波系统误差的原因,提出了减少和消除这一些系统误差的方法,并给实验验证。  相似文献   
2.
文章介绍利用不同质量链上两种裂变产物或同一质量链上母子体裂变产物的活度比来确定CTBT国际比对样品零时的方法。通过2001至2004年度CTBT放射性核素实验室滤材样品的国际比对对方法进行了检验,零时的计算值与参考值在不确定度范围内一致。   相似文献   
3.
环境热释光剂量计比对   总被引:1,自引:0,他引:1  
与日本化学分析中心进行了不同内容的环境热择光剂量计的比对。结果表明:双方的TLD无论是用X光机或放射源辐照,还是布放到环境中.结果都达到国内外的相关标准。  相似文献   
4.
为有效解决当前装备体系贡献率评估结果难以相互比较的难题,从装备体系建设与设计视角,选取装备额定条件下完成体系规定任务率作为装备体系贡献率的度量指标,将装备体系贡献率评估转化为装备体系设计中的装备完成体系规定任务率优化分配。运用求解优化模型的拉格朗日乘数法,得出所求条件极值的可能极值点,并作为装备体系内装备完成体系规定任务率的优化分配结果。针对装备体系内装备之间并联、串联和混联3种类型的关联协作关系,应用概率论和拉格朗日乘数法,分别构建和求解这3种类型的装备体系完成任务率函数和建设贡献率评估模型,实现了装备体系建设贡献率的统一度量和对比分析。算例结果验证了评估模型的有效性和可行性。  相似文献   
5.
Because of increased interest in the marine and atmospheric sciences in elemental carbon (EC), or black carbon (BC) or soot carbon (SC), and because of the difficulties in analyzing or even defining this pervasive component of particulate carbon, it has become quite important to have appropriate reference materials for intercomparison and quality control. The NIST “urban dust” Standard Reference Material® SRM 1649a is useful in this respect, in part because it comprises a considerable array of inorganic and organic species, and because it exhibits a large degree of (14C) isotopic heterogeneity, with biomass carbon source contributions ranging from about 2 % (essentially fossil aliphatic fraction) to about 32 % (polar fraction).A primary purpose of this report is to provide documentation for the new isotopic and chemical particulate carbon data for the most recent (31 Jan. 2001) SRM 1649a Certificate of Analysis. Supporting this is a critical review of underlying international intercomparison data and methodologies, provided by 18 teams of analytical experts from 11 institutions. Key results of the intercomparison are: (1) a new, Certified Value for total carbon (TC) in SRM 1649a; (2) 14C Reference Values for total carbon and a number of organic species, including for the first time 8 individual PAHs; and (3) elemental carbon (EC) Information Values derived from 13 analytical methods applied to this component. Results for elemental carbon, which comprised a special focus of the intercomparison, were quite diverse, reflecting the confounding of methodological-matrix artifacts, and methods that tended to probe more or less refractory regions of this universal, but ill-defined product of incomplete combustion. Availability of both chemical and 14C speciation data for SRM 1649a holds great promise for improved analytical insight through comparative analysis (e.g., fossil/biomass partition in EC compared to PAH), and through application of the principle of isotopic mass balance.  相似文献   
6.
As part of an international 222Rn measurement intercomparison conducted at Bermuda in October 1991, NIST provided standardized sample additions of known, but undisclosed (“blind”) 222Rn concentrations that could be related to U.S. national standards. The standardized sample additions were obtained with a calibrated 226Ra source and a specially-designed manifold used to obtain well-known dilution factors from simultaneous flow-rate measurements. The additions were introduced over sampling periods of several hours (typically 4 h) into a common streamline on a sampling tower used by the participating laboratories for their measurements. The standardized 222Rn activity concentrations for the intercomparison ranged from approximately 2.5 Bq · m−3 to 35 Bq · m−3 (of which the lower end of this range approached concentration levels for ambient Bermudian air) and had overall uncertainties, approximating a 3 standard deviation uncertainty interval, of about 6 % to 13 %. This paper describes the calibration and methodology for the standardized sample additions.  相似文献   
7.
随着我国特高压直流输电工程的全面启动,直流输电电压等级也由±500 kV 提高到±800 kV.为了使现有的特高压直流电压发生器的工作电压满足特高压直流输电技术发展的需要,将澳大利亚国家计量院研制的1000 kV 直流高压分压器测量系统作为标准直流高压分压器,采用电压比测量方法,与户内±1800 kV 直流高压分压器进行了比对试验.通过对测量不确定度各项影响分量的综合评定,表明±1800 kV 直流高压分压器在1000 kV 工作电压下的分压比变化率小于0.5%,能满足开展特高压直流绝缘技术研究和特高压直流设备相关产品检测工作的需要  相似文献   
8.
9.
This paper describes the results of an intercomparison of spectroradiometers for global and direct normal incidence irradiance in the visible and near‐infrared spectral regions together with an assessment of the impact these results may have on the estimation of the short‐circuit current (ISC) calibration of photovoltaic devices and on the spectral mismatch calculation. The intercomparison was conducted in the framework of the European project Apollon with the additional participation of external partners from the Italian project for the long‐term monitoring of solar radiation for photovoltaics. Six institutions and six spectroradiometer systems, representing different technologies and manufacturers, were involved. Prior to the intercomparison, all participating partners calibrated their own instrument(s) according to their usual procedures in order to verify the entire measuring and traceability chain. The difference in measured spectra shape and amplitude showed to have an impact on ISC calculation of less than 3% and less than 6% for single‐junction and multi‐junction devices, respectively. When only the shape of the spectra is considered, the spectral mismatch ranges from 1.7% to 4.7% depending on the spectral response of the device. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
10.
Because of recent advances in the production and installation of photovoltaic (PV) systems, the international conformity of PV module performance measurement has become increasingly important. The increase in PV production sites is particularly significant in the Asian region. The present paper summarizes and discusses the results of a round‐robin intercomparison of crystalline silicon modules among national laboratories and certified testing laboratories in the Asian region conducted from 2009 to 2011. Most of the values of Pmax measured at the different laboratories were within a ±2% range, although some Pmax results showed differences of up to about 3%. This result is comparable to that obtained in the recent intercomparison among international laboratories. Possible sources of difference in the measured values of Isc, Voc, FF, and Pmax are discussed, for further improvement of international conformity in PV measurement technologies. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
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