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1.
Arasa J  Royo S  Pizarro C  Martínez J 《Applied optics》1999,38(34):7009-7017
A new, to our knowledge, method for evaluating three-dimensional flux distributions for general filament light sources is presented. The main advantages of the developed model are its generality and its simplicity. From plots of the emitted luminous intensity, usually provided by the lamp's manufacturer, in three orthogonal planes a detailed account is given of how to establish flux emission from the light source in any direction. The method involves a selective smoothing procedure, a curve-fitting step, and a final interpolation. A full model is developed for a typical commercial filament bulb (Philips, Model P21W Inco K) that is quite common in many industrial applications. A fourth intensity plot, usually provided by the lamp's manufacturer, is used to validate the model. To confirm the validity of the model further, we present an industrial application (the photometric simulation of a car taillight) that uses the modeled Philips Model P21W source. A comparison between simulated data obtained by use of the developed P21W model and measured results at our industrial partner's laboratories reinforces the proposed source model.  相似文献   

2.
Protein microarrays are powerful tools to quantify and characterize proteins in multiplex assays. They have great potential within clinical diagnostics and prognostics, as they minimize consumption of both analyte and biological sample. Assays that do not require labeling of the biological specimen, henceforth called label-free, are vital for ease of clinical sample processing. Here, we evaluate two label-free techniques, reverse-phase and sandwich antibody assays, using microarrays on high-performance porous silicon surfaces and fluorescence detection. In view of increasing interest in reverse microarrays, this paper focuses on analytical sensitivity of the reverse assays compared to the more complex but highly sensitive sandwich assay. Sensitivity, linear range, and reproducibility of the two assays were compared using prostate-specific antigen (PSA) in buffer. The sandwich assay displayed 5 orders of magnitude lower detection limit (0.7 ng/mL) compared to the reverse assay (70 microg/mL). PSA at 50 nM (1.5 microg/mL) in cell lysates was detected by the sandwich assay but not by the reverse assay, demonstrating again a far lower detection limit for sandwich microarrays. In independent assay runs of PSA spiked in female serum, the sandwich assay had good linearity (R2 > 0.99) and reproducibility (coefficient of variation < or =15%), and the detection limit could be improved to 0.14 ng/mL. Without further signal amplification, the sandwich assay would be our choice for PSA analysis of clinical samples using a microarray technology platform.  相似文献   

3.
本文全面阐述了使用电荷耦合器件CCD制作的各种数字式相机的结构和性能特点,以及不同类型的CCD组成的工作原理,包括:线阵CCD、面阵CCD和两者的混合形式一面阵CCD扫描器。附表列有世界著名照相机厂家生产的典型数字式相机的技术性能,用途和参考价格。  相似文献   

4.
Probabilistic Safety Assessment is widely becoming the standard method for assessing, maintaining, assuring and improving the nuclear power plant safety. To achieve one of its many potential benefits, the optimization approach of surveillance requirements in technical specifications was developed. Surveillance requirements in technical specifications define the surveillance test intervals for the equipment to be tested and the testing strategy. This optimization approach based mainly on probabilistic safety assessment results consists of three levels: component level, system level and plant level. The application of this optimization approach on system level has shown that the risk based surveillance requirements differ from existing ones in technical specifications.  相似文献   

5.
Optimization of technical specification requirements and maintenance (TS&M) has been found interesting from the very beginning at Nuclear Power Plants (NPPs). However, the resolution of such a kind of optimization problem has been limited often to focus only on individual TS&M-related parameters (STI, AOT, PM frequency, etc.) and/or adopting an individual optimization criterion (availability, costs, plant risks, etc.). Nevertheless, a number of reasons exist (e.g. interaction, similar scope, etc.) that justify the interest to focus on the coordinated optimization of all of the relevant TS&M-related parameters based on multiple criteria.The purpose of this paper is on signifying benefits and improvement areas in performing the coordinated optimization of TS&M through reviewing the effectiveness and efficiency of common strategies for optimizing TS&M at system level. A case of application is provided for a stand-by safety-related system to demonstrate the basic procedure and to extract a number of conclusions and recommendations from the results achieved. Thus, it is concluded that the optimized values depend on the particular TS&M-related parameters being involved and the solutions with the largest benefit (minimum risk or minimum cost) are achieved when considering the simultaneous optimization of all of them, although increased computational resources are also required. Consequently, it is necessary to analyze not only the value reached but also the performance of the optimization procedure through effectiveness and efficiency measures which lead to recommendations on potential improvement areas.  相似文献   

6.
近年来,我国太阳能相关企业发展迅速。不久前,国务院颁布了《新能源产业振兴规划》。财政部会同住房城乡建设部在此之前也下达首批太阳能光电建筑应用补助资金,启动太阳能屋顶计划。为缓解光电产品国内应用不足的问题,财政部采取中央财政补贴措施,推动实施"太阳能屋顶计划"示范工程,2009年,补贴标准原则上定为20元/Wp(Wp代表太阳能电池的峰值功率)。但是,我国到目前为止还没有颁布有关建筑物光伏发电的标准,IEC、EN、UL等国际标准化组织  相似文献   

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8.
Systems, structures, and components of Nuclear Power Plants are subject to Technical Specifications (TSs) that establish operational limitations and maintenance and test requirements with the objective of keeping the risk associated to the plant within the limits imposed by the regulatory agencies. Recently, in an effort to improve the competitiveness of nuclear energy in a deregulated market, modifications to maintenance policies and TSs are being considered within a risk-informed viewpoint, which judges the effectiveness of a TS, e.g. a particular maintenance policy, with respect to its implications on the safety and economics of the system operation.In this regard, a recent policy statement of the US Nuclear Regulatory Commission declares appropriate the use of Probabilistic Risk Assessment models to evaluate the effects on the system of a particular TS. These models rely on a set of parameters at the component level (failure rates, repair rates, frequencies of failure on demand, human error rates, inspection durations, and others) whose values are typically affected by uncertainties. Thus, the estimate of the system performance parameters corresponding to a given TS value must be supported by some measure of the associated uncertainty.In this paper we propose an approach, based on the effective coupling of genetic algorithms and Monte Carlo simulation, for the multiobjective optimization of the TSs of nuclear safety systems. The method transparently and explicitly accounts for the uncertainties in the model parameters by attempting to minimize both the expected value of the system unavailability and its associated variance. The costs of the alternative TSs solutions are included as constraints in the optimization. An application to the Reactor Protection Instrumentation System of a Pressurized Water Reactor is demonstrated.  相似文献   

9.
10.
Abstract and Key Results
•  This paper addresses production function and technical efficiency in the context of multinational enterprises (MNEs). It applies the stochastic frontier production function technique (SFPF) to investigating a sample of U.S. manufacturing MNEs and finds that an MNE normally encounters two phases of “liability of internationalization” in the course of international expansion. In addition, it shows that the firms with intensive investment in R&D and advertising development tend to alleviate or even avoid the “liability of internationalization” and enjoy a prolonged period of effective international expansion.
•  The relationship between multinationality and meta production frontier (as well as technical efficiency) exhibits an upward horizontal S-curved relationship.
•  R&D and advertising intensity (RDAI) positively affects the relationship between multinationality and meta production frontier (as well as technical efficiency). In the case of very high RDAI, the S-curve transforms itself into an upward monotonous curve.
  相似文献   

11.
This study introduces a method to build a multi-domain matrix (MDM), visualizing the intended architecture of a system within the component, function, and parameter domains. The MDM is generated from textual function specifications that are subject to a specific grammatical structure and vocabulary based upon the functional basis and interaction basis as presented in the literature. Two types of functions are distinguished: functions specifying what functionality a particular component provides to another component, and functions specifying the internal working (transformation of flow) of a particular component. The fixed grammar for the specification of the two types of functions allows for the automated derivation of dependencies between components, between functions of components, and between system parameters. A case study on a navigation lock demonstrates that the system architecture generated from function specifications matches the architecture of the real lock system fairly well. As such the method can be used in the early design phase to reveal the product architecture that is embodied in the function specifications of system components. The method may also support modeling of high-definition DSMs of existing engineering systems.  相似文献   

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Setting as central theme the response of stakeholders to the challenges and offers of Risk Analysis, the paper proposes an approach meant to facilitate risk communication: mapping risk from the hazards perspective--that is, emphasizing the consequence-related factor in the standard risk representations. A working demonstration is presented to illustrate the concept, in relation to a decision support system (DSS) design that has caught, over the past few years, the interest of several authorities and forae in Switzerland and elsewhere, providing for useful exchanges between the risk community and stakeholders from major industries, infrastructure operations, finances and other areas.  相似文献   

14.
李伟  陈峰 《高技术通讯》2016,(4):396-406
利用德温特创新索引(DII)数据库的专利文献数据,通过产业竞争环境分析和主要竞争对手分析,从竞争情报的视角研究了超级电容器产业的技术竞争态势。通过计算专利技术生命周期、技术研发重点、主要专利优先权国家分布、主要研发机构等指标,明确了我国在该技术领域的位置,提出了发展我国超级电容器产业对策和建议。  相似文献   

15.
从1885年5月1日作为现代实用变压器诞生日算起,变压器产品的发展历经百年有余。变压器在铁芯材料、剪裁工艺、绕组型式、绝缘与冷却方式、结构外观、电气和机械特性等技术上不断改进并超越,甚至出现了革命性的产品(如超导变压器),而高效的理念从开始便得以奠基,即使在上世纪90世纪末也可以达到最高96%的效率水平。直至今天,人类依然为每年0.1%效率的提升而努力。与其他电力设备比较(如用电设备),变压器的效率令人羡慕,  相似文献   

16.
While the poor response implications of supply are often not elaborated on in the literature, postponement has recently been mentioned as a useful tool for managing supply risk and disruptions. To interpret this in a more complete manner, this paper has attempted to explore the role of postponement in supply chain risk management from a complexity perspective. After a review of the relevant literature, it first draws insights emerging from normal accident theory that addresses the system characteristics of catastrophic accidents and applies them to supply chain disruptions. This is followed by the utilisation of normal accident theory to explain the role of postponement in supply chain risk management. Building on this, this paper also investigates the complexity implications of some commonly recommended measures to mitigate supply chain disruptions. In certain circumstances, the introduction of those measures may add to the complexity of a system and thus become inherently infeasible. The paper concludes with a summary and some suggestions for further research.  相似文献   

17.
18.
An approach using semantic metrics to provide insight into software quality early in the design phase of software development by automatically analysing natural language (NL) design specifications for object-oriented systems is presented. Semantic metrics are based on the meaning of software within the problem domain. In this paper, we extend semantic metrics to analyse design specifications. Since semantic metrics can now be calculated from early in design through software maintenance, they provide a consistent and seamless type of metric that can be collected through the entire lifecycle. We discuss our semMet system, an NL-based program comprehension tool we have expanded to calculate semantic metrics from design specifications. To validate semantic metrics from design specifications and to illustrate their seamless nature across the software lifecycle, we compare semantic metrics from different phases of the lifecycle, and we also compare them to syntactically oriented metrics calculated from the source code. Results indicate semantic metrics calculated from design specifications can give insight into the quality of the source code based on that design. Also, these results illustrate that semantic metrics provide a consistent and seamless type of metric that can be collected through the entire lifecycle.  相似文献   

19.
The role of technical specifications and maintenance (TSM) activities at nuclear power plants (NPP) aims to increase reliability, availability and maintainability (RAM) of Safety-Related Equipment, which, in turn, must yield to an improved level of plant safety. However, more resources (e.g. costs, task force, etc.) have to be assigned in above areas to achieve better scores in reliability, availability, maintainability and safety (RAMS). Current situation at NPP shows different programs implemented at the plant that aim to the improvement of particular TSM-related parameters where the decision-making process is based on the assessment of the impact of the change proposed on a subgroup of RAMS+C attributes.This paper briefly reviews the role of TSM and two main groups of improvement programs at NPP, which suggest the convenience of considering the approach proposed in this paper for the Integrated Multi-Criteria Decision-Making on changes to TSM-related parameters based on RAMS+C criteria as a whole, as it can be seem as a decision-making process more consistent with the role and synergic effects of TSM and the objectives and goals of current improvement programs at NPP. The case of application to the Emergency Diesel Generator system demonstrates the viability and significance of the proposed approach for the Multi-objective Optimization of TSM-related parameters using a Genetic Algorithm.  相似文献   

20.
We discuss the physics of the Efimov effect from a renormalization group viewpoint using the concept of limit cycles. Furthermore, we discuss recent experiments providing evidence for the Efimov effect in ultracold gases and its relevance for nuclear systems.  相似文献   

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