Results are presented of an experimental study on the efficiency of the ion source with Penning ionization. Mercury was used as a separated sample. Measurements of the source efficiency for Hg were carried out for the...
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Results are presented of an experimental study on the efficiency of the ion source with Penning ionization. Mercury was used as a separated sample. Measurements of the source efficiency for Hg were carried out for the source operating on He and Ar, i. e. gases with which additional Hg ionization could result due to the Penning effect. A simple theoretical model of the plasma in the ion source was developed and the pressure dependence of the ratio of the source efficiencies for the separated sample and carrier gas was calculated. By parametrically fitting the predicted source efficiency ratio equation to the experimental data, estimates of certain coefficients for the processes taking place in the source plasma could be derived.
This paper presents a new method to incorporate flexible AC transmission system (FACTS) devices in optimal power flow (OPF) problem. Through power injection model of FACTS devices, their control to power system is exp...
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ISBN:
(纸本)0780379896
This paper presents a new method to incorporate flexible AC transmission system (FACTS) devices in optimal power flow (OPF) problem. Through power injection model of FACTS devices, their control to power system is expressed as the additional power equations at the nodes and the branches where FACTS devices are located. These additional power equations are convenient in combination with OPF algorithm based on non-linear interior point (IP) programming. A two-part calculation structure is introduced in order to make full use of the existing OPF algorithm and related software in EMS. Digital simulations of the modified IEEE 30-node system located with multiple FACTS devices are present to test the effectiveness and efficiency of this work. The study also shows that FACTS devices are capable of providing an economically and technically attractive solution to power systems congestion problems.
India is a developing capitalist country. Since 1947 when it broke away from British colonial rule and obtained independence, it has gradually established capitalist political and economic systems, and embarked upon t...
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India is a developing capitalist country. Since 1947 when it broke away from British colonial rule and obtained independence, it has gradually established capitalist political and economic systems, and embarked upon the development path of modernization. In political aspect, India has given full scope to political stability with its unique political system and maintained the robustness of Indian capitalist political and economic systems. However, in the meantime, Indian political system is faced with certain problems and challenges.
About 90 percent of people with Parkinson's disease (PD) experience decreased functional communication due to the presence of voice and speech disorders associated with dysarthria that can be characterized by mono...
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Modulation via Fourier transform division multiplexing (FTDM) has been suggested for transmission over channels whose signal-to-noise ratios, as functions of frequency, are far from flat. Original designs following th...
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Modulation via Fourier transform division multiplexing (FTDM) has been suggested for transmission over channels whose signal-to-noise ratios, as functions of frequency, are far from flat. Original designs following the classical water-pouring theorem left a large gap between the theoretical promise of the method and the actual rates achieved. The author presents heuristic input-power allocations for enhancing the performance of such schemes. He also considers FTDM under peak-power constraints.< >
This paper describes how to employ principles of Mistake-Proofing in the teaching of engineering problem solving. The problem solving process starts with an intentionally brief introduction to the concepts of variabil...
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This paper describes how to employ principles of Mistake-Proofing in the teaching of engineering problem solving. The problem solving process starts with an intentionally brief introduction to the concepts of variability, robustness and sensitivity. Through solving a number of problems of increasing complexity or conceptual difficulty, students develop a list of mistake-proofing principles. Development of the list is based on the use of physical and chemical principles as tools for conceptually solving given problems. All solutions are conceptual only and have a goal of mistake-proofing the designs and processes in question. The solutions are then classified according to their mistake-proofing robustness. Student work is intentionally guided by the instructor, and switches between individual work, small team work, and brainstorming done together by the entire class. Strong emphasis is put on process of defining goals of the redesign process, and critical description of shortcomings of the present stage of product or process design. A particular emphasis however, is put on knowledge of scientific principles which may provide ideal solutions to the problem at hand. In that respect, mistake-proofing of certain designs based on their geometry, as well as production processes prove to be fairly easy to understand and students are able to come up with a variety of solutions. Other advantages, limitations and disadvantages of using Mistake-Proofing as the base for teaching principles of problem solving are also provided and discussed from perspectives of faculty and students. A number of common and specialized devices used in exercises for defining physical principles underlying an engineering problem at hand are also listed in the paper.
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