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   46篇
  免费   3篇
化学工业   14篇
建筑科学   3篇
能源动力   6篇
水利工程   3篇
无线电   5篇
一般工业技术   4篇
冶金工业   8篇
自动化技术   6篇
  2024年   1篇
  2023年   1篇
  2022年   4篇
  2020年   1篇
  2019年   1篇
  2018年   3篇
  2017年   1篇
  2016年   1篇
  2014年   1篇
  2013年   3篇
  2011年   3篇
  2010年   1篇
  2009年   3篇
  2008年   1篇
  2007年   3篇
  2003年   2篇
  1999年   1篇
  1998年   2篇
  1997年   2篇
  1996年   1篇
  1995年   3篇
  1993年   1篇
  1992年   1篇
  1991年   3篇
  1990年   1篇
  1988年   1篇
  1979年   1篇
  1978年   1篇
  1972年   1篇
排序方式: 共有49条查询结果,搜索用时 0 毫秒
11.
A real-time vision module for interactive perceptual agents   总被引:2,自引:0,他引:2  
Abstract. Interactive robotics demands real-time visual information about the environment. Real-time vision processing, however, places a heavy load on the robot's limited resources, which must accommodate multiple other processes running simultaneously. This paper describes a vision module capable of providing real-time information from ten or more operators while maintaining at least a 20-Hz frame rate and leaving sufficient processor time for a robot's other capabilities. The vision module uses a probabilistic scheduling algorithm to ensure both timely information flow and a fast frame capture. In addition, it tightly integrates the vision operators with control of a pan-tilt-zoom camera. The vision module makes its information available to other modules in the robot architecture through a shared memory structure. The information provided by the vision module includes the operator information along with a time stamp indicating information relevance. Because of this design, our robots are able to react in a timely manner to a wide variety of visual events.  相似文献   
12.
Indoor air pollution from burning solid fuels for cooking is a major environmental health problem in developing countries, predominantly affecting children and women. Traditional household energy practices also contribute to substantial time loss and drudgery among households. While effective interventions exist, levels of investment to date have been very low, in part due to lack of evidence on economic viability. Between 2004 and 2007, different combinations of interventions – improved stoves, smoke hoods and a switch to liquefied petroleum gas – were implemented in poor communities in Nepal, Sudan and Kenya. The impacts were extensively evaluated and provided the basis for a household-level cost-benefit analysis, which essentially followed the methodology proposed by the World Health Organization. The results suggest that interventions are justified on economic grounds with estimated internal rates of return of 19%, 429% and 62% in Nepal, Kenya and Sudan, respectively. Time savings constituted by far the most important benefit followed by fuel cost savings; direct health improvements were a small component of the overall benefit. This paper describes the methodology applied, discusses the findings and highlights the methodological challenges that arise when a global approach is applied to a local programme.  相似文献   
13.
OBJECTIVES: To provide an overview of a comprehensive and integrated case-management program that incorporates principles of assertive community treatment and combines effective medical and psychosocial interventions and to present the results of a process and outcome evaluation of the program, with particular emphasis on its impact on service utilization and consumer satisfaction. METHOD: Data on demographic, clinical, and several outcome measures were collected on all patients who received care in the program for a minimum of 6 months. For process evaluation we assessed the extent to which the program adhered to its goals and satisfied the patients, their families, and community-service agencies. Outcome-evaluation data on the number and length of hospital admissions were compared for each subject with individual historical data for a period equal to the time spent in the program. In addition, relapses of psychotic symptoms that did not result in hospital admissions were calculated for each patient while in the program. RESULTS: Demographic, clinical, and treatment characteristics of clients show that the program has succeeded in maintaining its focus on providing services to relatively chronically ill patients with psychotic disorders over a mean period of 3 years. The process-evaluation data indicated a high level of satisfaction by patients, families, and other service agencies with the services received. Information on outcome variable showed that the program achieved significantly lower rates of hospital admissions and relapse of psychosis than expected. There was a highly significant reduction achieved in the utilization of inpatient hospital resources for patients receiving care in the program. Most of the inpatient service utilization was attributed to patients either who were resistant to treatment with antipsychotic agents or who refused to accept or comply with medication. CONCLUSIONS: It is possible to provide effective continuity of care from inpatient treatment to community adjustment for most individuals with psychotic disorders across the spectrum by blending hospital and community resources within an integrated case-management model of care.  相似文献   
14.
A new approach for the preparation of metal supported montmorillonite catalyst is reported here for the first time. The polyol process in which ethylene glycol is used as reducing agent was employed for the preparation of uniformly distributed copper metal particles on and within the montmorillonite matrix. A hydroxy copper acetate intercalated form of montmorillonite was refluxed at 195 °C with liquid ethylene glycol for 6 h. The reduction of copper acetate to copper metal was apparent from the red color of the reduced product. An X-ray powder diffraction pattern showed the deposition of copper metal on the external surface of montmorillonite and scanning electron micrographs exhibited uniformly distributed spherical copper metal particles of about 0.5 m size. This process may also be extended for the preparation of other fine metal particles supported on montmorillonite catalysts.  相似文献   
15.
In a slurry of radioactive particles, radiation count and solids concentration are related by a Fredholm equation of the first kind. Two iterative methods are described and conditions for their convergence are given. Two hypothetical examples illustrate computational difficulties and their solution. Experiments with slurries of radioactive praseodymium oxalate demonstrate the feasibility of the method. Solutions are proposed for various practical problems which arise.  相似文献   
16.
17.
By incorporating on-demand resources, software and data for collaborative services through the Internet, the conventional Information Technology enterprise has been transformed by cloud computing. Based on the pay-per-use approach, Infrastructure, platform or Software resources and servers located across data centres are among the several types of resources offered to consumers in cloud computing. Data centres handle these resources. These resources are constantly provisioned to users based on their availability, demand, and quality requirements. Cloud computing systems are known as one of the largest utilisers of energy resources all over the world. Also, power consumption has become a crucial aspect as most cloud computing systems work on traditional nonrenewable resources of energy. In order to make data centres environment-friendly, there is a need for optimal approaches to reduce energy consumption and their hazardous effects on the environment. To analyse different available strategies for building and maintaining an energy-efficient cloud is the main objective of this paper. The paper will comprehensively review several energy-efficient resource provisioning methods and provide a graphical comparative study of Quality of Service (QoS) Metrics in cloud computing. Moreover, the present study identifies the areas of study that need to be further improved to increase the energy efficiency of cloud computing systems.  相似文献   
18.
Effects of orbital and structural initial conditions, such as initial structural axial deformation, pitch (attitude) angle, and orbit altitude have been investigated on the subsequent orbital motion (time variation of orbit radius), attitude or pitch motion (time variation of pitch angle), and axial motion (time variation of axial length) of a large space structure in low earth orbit (LEO) and geosynchronous earth orbit (GEO). The space structure is assumed to be only axially flexible and executing a planar motion under the action of the earth's gravitational force. In LEO it is observed that the initial values of the axial deformation and pitch angle have appreciable effects on the structure's subsequent axial and attitude motions, whereas they have negligible effects on the structure's orbital motion. In GEO, the effects are found similar to those in LEO, except that the initial values of pitch angle have no effect on axial deformation. Furthermore, the investigation shows that the response of the space structure is greatly affected by the change in the orbit altitude. The study also indicates that flexibility of the structure has significant influence on its pitch librational motion.  相似文献   
19.
BACKGROUND: Positron emission tomographic and postmortem studies comparing schizophrenic patients with healthy control subjects have found medial prefrontal cortical and anterior cingulate abnormalities that suggest dysfunction in glutamatergic neurons. The glutamate used for nerve signal transduction is predominantly derived from glutamine. After signal transduction, glutamate released into the synapse is converted to glutamine in glial cells, transported back to the presynaptic neuron, and reconverted to glutamate for reuse. In this study, levels of glutamate and glutamine were examined by means of in vivo proton (1H) magnetic resonance spectroscopy. METHODS: Localized in vivo 1H spectra were acquired from a 4.5-cm3 volume in the left medial prefrontal cortex encompassing portions of Brodmann areas 24, 32, and 9 in 10 never-treated schizophrenic subjects and 10 healthy controls of comparable age, sex, handedness, education, and parental education. From each spectrum, metabolite levels were estimated for glutamate and glutamine, as well as 10 other metabolites and 3 macromolecules, by means of a noninteractive computer program that combined modeled in vitro spectra of every metabolite to reconstruct each in vivo spectrum. RESULTS: A significant increase in glutamine level was found in the medial prefrontal cortex of the schizophrenic patients compared with controls. N-acetylaspartate and other measured metabolites and macromolecules were not significantly changed in schizophrenics. CONCLUSION: Increased glutamine levels in the medial prefrontal region most likely reflect decreased glutamatergic activity in this region in never-treated schizophrenic patients compared with healthy controls.  相似文献   
20.
The Logarithmic Mean Divisia Index (LMDI) method of complete decomposition is used to examine the role of three factors (electricity production, electricity generation structure and energy intensity of electricity generation) affecting the evolution of CO2 emissions from electricity generation in seven countries. These seven countries together generated 58% of global electricity and they are responsible for more than two-thirds of global CO2 emissions from electricity generation in 2005. The analysis shows production effect as the major factor responsible for rise in CO2 emissions during the period 1990–2005. The generation structure effect also contributed in CO2 emissions increase, although at a slower rate. In contrary, the energy intensity effect is responsible for modest reduction in CO2 emissions during this period. Over the 2005–2030 period, production effect remains the key factor responsible for increase in emissions and energy intensity effect is responsible for decrease in emissions. Unlike in the past, generation structure effect contributes significant decrease in emissions. However, the degree of influence of these factors affecting changes in CO2 emissions vary from country to country. The analysis also shows that there is a potential of efficiency improvement of fossil-fuel-fired power plants and its associated co-benefits among these countries.  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