首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   63篇
  免费   4篇
化学工业   11篇
金属工艺   8篇
机械仪表   2篇
建筑科学   6篇
能源动力   2篇
轻工业   6篇
无线电   8篇
一般工业技术   5篇
冶金工业   11篇
自动化技术   8篇
  2022年   1篇
  2021年   1篇
  2020年   2篇
  2019年   3篇
  2018年   2篇
  2017年   2篇
  2016年   3篇
  2014年   3篇
  2013年   4篇
  2012年   4篇
  2011年   5篇
  2010年   1篇
  2009年   3篇
  2008年   2篇
  2007年   4篇
  2006年   1篇
  2004年   3篇
  2003年   2篇
  2002年   1篇
  2001年   1篇
  2000年   4篇
  1999年   3篇
  1998年   2篇
  1997年   2篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1985年   1篇
  1976年   2篇
  1975年   1篇
排序方式: 共有67条查询结果,搜索用时 15 毫秒
1.
Practitioners are continuing to develop egress modelling software for the design of the built environment. These models require data about human behaviour and factors for calibration, validation and verification. This study aims to address the specific data and knowledge gap: emergency egress of the elderly. Such data are difficult to collect given privacy and consent concerns, with strong relationships generally being required between residences and researchers. Through the observation of nine fire drills at six Canadian long-term care (LTC) and retirement homes, specific evacuation actions and behaviour were observed for 37 staff members and information about the evacuation of 56 residents was collected. These drills demonstrated that emergency egress in LTC and retirement homes is highly staff dependent with 72% of residents recorded requiring full assistance at all stages of movement in evacuation, and that the type of announced/unannounced drill and level of resident care will affect the type of data collected. The development of travel speed and pre-movement is discussed subject to limitation with qualitative behavioural insights of residents that were observed. This study provides valuable methodological discussion on how to conduct behavioural studies in similar highly restricted research environments. Specific attention is given to understanding the considerations that must be made when using fire drills as data sources, and the impact that these can have on using such data for modelling. This study may inform the initial setup and programming of evacuation models from an actions and behavioural perspectives of staff members and residents.  相似文献   
2.
A JEOL JEM-3000F field emission, analytical, high-resolution transmission electron microscope (HRTEM) was used to study InN films grown on sapphire substrates. It was found that, while the InN films maintained the hexagonal (wurtzite) structure, InN nanodomains with a cubic (zincblende) structure were also formed in the films. Nanobeam electron diffraction techniques were applied for identification of the cubic phase. The identification of the cubic InN was confirmed by HRTEM structural imaging. The cubic InN nanodomains are 3-10 nm in diameter, and are orientated in two different orientations with their [110](cubic) and [110](cubic) axes parallel to each other and their (111)(cubic) planes parallel to the (0001)(hex) plane of the hexagonal InN.  相似文献   
3.
4.
In this paper, the inversion processing of cascade impactor data to construe continuous size distributions within fine particulate matter (PM2.5) is examined for residential oil furnace and fireplace appliance emissions. Impactor data from tests with these emissions sources are selected for the challenges they pose to comprehending the size distributions of aerosol mass and chemical species. In specific, the oil furnace aerosol offers an opportunity to apply data inversion to study a bimodal lognormal distribution in which much of the aerosol mass is impactor-penetrating nanoparticles . The fireplace emissions on the other hand cover the issue of a chemical size distribution, which is subject to particle loss and characterized by a single lognormal, accumulation mode peak. Computational steps relevant to the application of the data inversion are illustrated in detail. Evaluation of correlation coefficients (0.992) indicates that the inversion model predictions fit the impactor data well. Simulations of systematic measurement error (±10%) at each impactor stage are shown to have a negligible impact on the inversion results for test data. It is concluded that data inversion can be effective when (i) source emissions contain a portion of particles that falls outside the measurement range of cascade impactors, (ii) a mass size distribution of an individual species is determined without the knowledge of the total mass concentration for that species, or when (iii) losses in the particle charger system are significant.  相似文献   
5.
This paper reports a novel stable adaptive identifier on the group of rigid-body rotations, and its application to a sensor-calibration problem arising in underwater vehicle navigation. The problem addressed is the identification of an unknown rigid-body rotation map from input-output data. General least-squares (LS) and adaptive identification techniques are commonly employed to identify general linear maps from input-output data, but do not guarantee that the resulting identified map is a rigid-body rotation. At present, an LS singular value decomposition approach is the standard method for identification constrained to the group of rigid-body rotations. This paper reports the first exact adaptive identifier on the group of rigid-body rotations, together with a proof of asymptotic stability. Techniques for navigating underwater vehicles are reviewed, and the Doppler-alignment calibration problem is posed. The reported adaptive identifier is employed to solve this problem, and performance of this adaptive identifier is evaluated on both laboratory and field experimental data. The results reported herein compare favorably with results obtained via previously reported LS techniques. The methodology reported herein may be of broader interest because of its applicability to more general problems in the identification, dynamics, and control on the group of rigid-body motions  相似文献   
6.
OBJECTIVES: This report describes how the 1995 National Survey of Family Growth (NSFG) was designed, planned, and implemented. The NSFG is a national survey of women 15-44 years of age designed to provide national estimates of factors affecting pregnancy and birth rates and the health of women and infants. Planning for the 1995 NSFG began in 1990 at a formal conference with the survey's data users. Suggestions for substantial changes and improvements in the survey were made there and carried out by NSFG staff and the NSFG contractor--the Research Triangle Institute (RTI). METHODS: The survey was converted from paper and pencil interviewing to Computer-Assisted Personal Interviewing (CAPI) to improve the quality, consistency, and timeliness of the data. At the same time, event histories of the respondent's work, education, family background, cohabitation, and sexual partners were added to lend explanatory power to the survey. These changes made the interview and the CAPI program long--average interview length was 103 minutes--and complex, but the CAPI program worked very well. RESULTS: About 260 female interviewers were trained for 7 days in January 1995. These interviewers completed a total of 10,847 interviews with women 15-44 years of age, for a response rate of 79 percent. This report describes how the survey was planned and designed and how the data were collected, edited, and processed for public use. This report may be of interest to NSFG data users and to those planning other computer-assisted surveys.  相似文献   
7.
8.
9.
The performance of multijunction solar cells has been measured over a range of temperatures and illumination intensities. Temperature coefficients have been extracted for three‐junction cell designs that are in production and under development. A simple diode model is applied to the three‐junction performance as a means to predict performance under operating conditions outside the test range. These data may be useful in guiding the future optimization of concentrator solar cells and systems. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
10.
在加工过程中,应变梯度硬化会消耗更多的外力,引起不必要的耗损.从应变梯度硬化角度出发,对平面弯曲过程的几何关系进行了分析,得到了几何必需位错密度与应变梯度的理论关系式,并据此建立了模型预测金属薄板平面微型弯曲过程中应变梯度与薄板厚度的关系.预测模型计算结果与其他预测方法的结果一致.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号