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981.
A new method for manufacturing multiwall carbon nanotubes by the current annealing in vacuum of the graphite paper saturated with Ni, Co, and Fe catalysts is designed. By using a scanning tunnel microscope, structural characteristics of the modified graphite paper are studied. Y- and V-shaped nanotubes are found.  相似文献   
982.
A new method is presented for analyzing the effects of self-absorption on photoluminescence integrating sphere quantum yield measurements. Both the observed quantum yield and luminescence spectrum are used to determine the self-absorption probability, taking into account both the initial emission and subsequent absorption and reemission processes. The analysis is experimentally validated using the model system of the laser dye perylene red dispersed in a polymer film. This approach represents an improvement over previous methods that tend to overestimate the true quantum yield, especially in cases with high sample absorbance or quantum yield values.  相似文献   
983.
The code STATFLUX, implementing a new and simple statistical procedure for the calculation of transfer coefficients in radionuclide transport to animals and plants, is proposed. The method is based on the general multiple-compartment model, which uses a system of linear equations involving geometrical volume considerations. Flow parameters were estimated by employing two different least-squares procedures: Derivative and Gauss-Marquardt methods, with the available experimental data of radionuclide concentrations as the input functions of time. The solution of the inverse problem, which relates a given set of flow parameter with the time evolution of concentration functions, is achieved via a Monte Carlo simulation procedure.

Program summary

Title of program:STATFLUXCatalogue identifier:ADYS_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADYS_v1_0Program obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandLicensing provisions: noneComputer for which the program is designed and others on which it has been tested:Micro-computer with Intel Pentium III, 3.0 GHzInstallation:Laboratory of Linear Accelerator, Department of Experimental Physics, University of São Paulo, BrazilOperating system:Windows 2000 and Windows XPProgramming language used:Fortran-77 as implemented in Microsoft Fortran 4.0. NOTE: Microsoft Fortran includes non-standard features which are used in this program. Standard Fortran compilers such as, g77, f77, ifort and NAG95, are not able to compile the code and therefore it has not been possible for the CPC Program Library to test the program.Memory required to execute with typical data:8 Mbytes of RAM memory and 100 MB of Hard disk memoryNo. of bits in a word:16No. of lines in distributed program, including test data, etc.:6912No. of bytes in distributed program, including test data, etc.:229 541Distribution format:tar.gzNature of the physical problem:The investigation of transport mechanisms for radioactive substances, through environmental pathways, is very important for radiological protection of populations. One such pathway, associated with the food chain, is the grass-animal-man sequence. The distribution of trace elements in humans and laboratory animals has been intensively studied over the past 60 years [R.C. Pendlenton, C.W. Mays, R.D. Lloyd, A.L. Brooks, Differential accumulation of iodine-131 from local fallout in people and milk, Health Phys. 9 (1963) 1253-1262]. In addition, investigations on the incidence of cancer in humans, and a possible causal relationship to radioactive fallout, have been undertaken [E.S. Weiss, M.L. Rallison, W.T. London, W.T. Carlyle Thompson, Thyroid nodularity in southwestern Utah school children exposed to fallout radiation, Amer. J. Public Health 61 (1971) 241-249; M.L. Rallison, B.M. Dobyns, F.R. Keating, J.E. Rall, F.H. Tyler, Thyroid diseases in children, Amer. J. Med. 56 (1974) 457-463; J.L. Lyon, M.R. Klauber, J.W. Gardner, K.S. Udall, Childhood leukemia associated with fallout from nuclear testing, N. Engl. J. Med. 300 (1979) 397-402]. From the pathways of entry of radionuclides in the human (or animal) body, ingestion is the most important because it is closely related to life-long alimentary (or dietary) habits. Those radionuclides which are able to enter the living cells by either metabolic or other processes give rise to localized doses which can be very high. The evaluation of these internally localized doses is of paramount importance for the assessment of radiobiological risks and radiological protection. The time behavior of trace concentration in organs is the principal input for prediction of internal doses after acute or chronic exposure. The General Multiple-Compartment Model (GMCM) is the powerful and more accepted method for biokinetical studies, which allows the calculation of concentration of trace elements in organs as a function of time, when the flow parameters of the model are known. However, few biokinetics data exist in the literature, and the determination of flow and transfer parameters by statistical fitting for each system is an open problem.Restriction on the complexity of the problem:This version of the code works with the constant volume approximation, which is valid for many situations where the biological half-live of a trace is lower than the volume rise time. Another restriction is related to the central flux model. The model considered in the code assumes that exist one central compartment (e.g., blood) that connect the flow with all compartments, and the flow between other compartments is not included.Typical running time:Depends on the choice for calculations. Using the Derivative Method the time is very short (a few minutes) for any number of compartments considered. When the Gauss-Marquardt iterative method is used the calculation time can be approximately 5-6 hours when ∼15 compartments are considered.  相似文献   
984.
Consideration is given to the problem of large-scale projects competition in the formulation motivated by real problems of defining the rational development of oil and gas transportation systems. The problem is formulated as a noncooperative game of n persons. Standard existence theorems and algorithms for computing the Nash equilibrium solutions are not applicable to it. For the case when all functional parameters of the problem are defined by exponential functions, a finite solution algorithm is proposed. Here is developed the approach proposed and studied in [1–5].  相似文献   
985.
OBJECTIVE: We explore whether ecological interface design (EID) principles can be applied to the design of an auditory display for anesthesia monitoring. BACKGROUND: EID examples focus almost exclusively on visual displays. In the anesthesia work environment, however, auditory displays may provide better individual and team awareness of patient state. METHOD: Using a work domain analysis of physiological monitoring in anesthesia, we identify information to display. Using the skills, rules, and knowledge distinction we identify cognitive control needed. Using semantic mapping we map physiological variables and constraints to auditory dimensions. RESULTS: EID principles do not address when information should be displayed and to whom. An attentional mapping stage helps to specify answers to these questions so that a workable auditory display for anesthesia monitoring is achieved. CONCLUSION: EID principles of representing work domain functional structure and minimizing resource-demanding cognitive control are necessary but insufficient to specify requirements for an effective auditory display. Also needed are analyses of control tasks, strategies, and the social organization of work. Such analyses are an integral part of the broader cognitive work analysis framework from which EID emerged. APPLICATION: Actual or potential uses of this research include the design of displays that support continuous peripheral awareness in collaborative multimodal work environments.  相似文献   
986.
Recently, a number of empirical studies have compared the performance of PCA and ICA as feature extraction methods in appearance-based object recognition systems, with mixed and seemingly contradictory results. In this paper, we briefly describe the connection between the two methods and argue that whitened PCA may yield identical results to ICA in some cases. Furthermore, we describe the specific situations in which ICA might significantly improve on PCA  相似文献   
987.
The electrooxidation of homocysteine, glutathione (GSH), 2-mercapto ethanesulfonic acid and cephalexin at boron-doped diamond (BDD) electrodes and glassy carbon (GC) electrodes was investigated by cyclic voltammetry. The oxidation of these sulfur-containing compounds exhibited well-defined irreversible responses. This preliminary study has shown that BDD has better sensitivity than GC. Concentration dependence has been studied and indicated the promise of using BDD electrodes for quantitative determination. All of the compounds displayed recognizable oxidation peaks at BDD electrodes at millimolar concentration levels. Scan rate dependence of GSH has been examined. It was shown that there was no adsorption on the surface of the BDD electrode for the low concentration.  相似文献   
988.
To create successful interactive systems, user interface designers need to cooperate with developers and application domain experts in an interdisciplinary team. These groups, however, usually lack a common terminology to exchange ideas, opinions and values. This paper presents an approach that uses pattern languages to capture this knowledge in software development, human-computer interaction (HCI) and the application domain. A formal, domain-independent definition of design patterns allows for computer support without sacrificing readability, and pattern use is integrated into the usability engineering life cycle. As an example, experience from building an award-winning interactive music exhibit was turned into a pattern language, which was then used to inform follow-up projects and support HCI education.An earlier version of this paper appeared in theProceedings of the DIS 2000 International Conference on Designing Interactive Systems (16–19 August 2000, New York) and appears by permission of the ACM Press.  相似文献   
989.
A multi-agent intelligent system for efficient ERP maintenance   总被引:9,自引:0,他引:9  
The Enterprise Resource Planning (ERP) system is an enterprise-wide integrated software package designed to uphold the highest quality standards of business process. However, for the time being, when the business condition has been changed, the system may not guarantee that the process embedded in ERP is still best. Moreover, since the ERP system is very complex, maintaining the system by trial and error is very costly. Hence, this paper aims to construct a support system that adjusts ERP system to environmental changes. To do so, we adopt multi-agent intelligent technology that enables autonomous cooperation with one another to monitor ERP databases and to find any exceptional changes and then analyze how the changes will affect ERP performance. Moreover, Petri net is applied to manage the complexity and dynamics of agents’ behavior. To show the feasibility of the idea, a prototype agent system, ERP/PN, is proposed and an experiment is conducted.  相似文献   
990.
An NP-hard production–distribution problem for one product over a multi-period horizon is investigated. The aim is to minimize total cost taking production setups, inventory levels and distribution into account. An integer linear model is proposed as a compact problem specification but it cannot be solved to optimality for large instances. Instead of using a classical two-phase approach (production planning and then route construction for each day), metaheuristics that simultaneously tackle production and routing decisions are developed: a GRASP (greedy randomized adaptive search procedure) and two improved versions using either a reactive mechanism or a path-relinking process. These algorithms are evaluated on 90 randomly generated instances with 50, 100 and 200 customers and 20 periods. The results confirm the interest of integrating production and distribution decisions, compared to classical two-phase methods. Moreover, reaction and path-relinking give better results than the GRASP alone.  相似文献   
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