6,988 research outputs found

    Economic reforms and inequality in China

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    This paper investigates the theoretical relationship between economic reforms and inequalities in socialist countries and tests it empirically in the case of China. The paper argues that the issue of whether market oriented reforms are likely to increase or decrease inequality in the former socialist economies is an empirical question which cannot be settled by a priori reasoning. On the one hand, economic inequality may rise with the reintroduction of property income and incentive payments and the reduction of barriers to opportunity for labor and capital to fully realize their highest earning potentials, On the other hand, inequality may decline with the decentralization of property rights, information and the reduction of barriers to the movement of goods and productive factors. The Chinese experience shows that economic inequalities did not increase but decline slightly during the first stage of the reforms. But they rose during the second stage of the reforms. Hence, the Chinese experience is largely congruent with the Szelenyi-Manchin hypothesis

    Energy Management for a User Interactive Smart Community: A Stackelberg Game Approach

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    This paper studies a three party energy management problem in a user interactive smart community that consists of a large number of residential units (RUs) with distributed energy resources (DERs), a shared facility controller (SFC) and the main grid. A Stackelberg game is formulated to benefit both the SFC and RUs, in terms of incurred cost and achieved utility respectively, from their energy trading with each other and the grid. The properties of the game are studied and it is shown that there exists a unique Stackelberg equilibrium (SE). A novel algorithm is proposed that can be implemented in a distributed fashion by both RUs and the SFC to reach the SE. The convergence of the algorithm is also proven, and shown to always reach the SE. Numerical examples are used to assess the properties and effectiveness of the proposed scheme.Comment: 6 pages, 4 figure

    Feasibility of Using Discriminate Pricing Schemes for Energy Trading in Smart Grid

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    This paper investigates the feasibility of using a discriminate pricing scheme to offset the inconvenience that is experienced by an energy user (EU) in trading its energy with an energy controller in smart grid. The main objective is to encourage EUs with small distributed energy resources (DERs), or with high sensitivity to their inconvenience, to take part in the energy trading via providing incentive to them with relatively higher payment at the same time as reducing the total cost to the energy controller. The proposed scheme is modeled through a two-stage Stackelberg game that describes the energy trading between a shared facility authority (SFA) and EUs in a smart community. A suitable cost function is proposed for the SFA to leverage the generation of discriminate pricing according to the inconvenience experienced by each EU. It is shown that the game has a unique sub-game perfect equilibrium (SPE), under the certain condition at which the SFA's total cost is minimized, and that each EU receives its best utility according to its associated inconvenience for the given price. A backward induction technique is used to derive a closed form expression for the price function at SPE, and thus the dependency of price on an EU's different decision parameters is explained for the studied system. Numerical examples are provided to show the beneficial properties of the proposed scheme.Comment: 7 pages, 4 figures, 3 tables, conference pape

    Ho3+ To Yb3+ Back Transfer And Thermal Quenching Of Up-Conversion Green Emission In Fluoride-Crystals

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    Energy transfer from Ho3+ to Yb3+ has been demonstrated in fluoride crystals such as KYF4, BaY2F8, and LiYF4. This transfer was found to occur above a certain temperature and its efficiency increases with temperature. It accounts for the thermal quenching of green emission from upconverted Ho3+ and partly explains the failure, to date, to obtain room temperature, Yb3+ sensitized Ho3+ upconversion lasers in these three hosts. Low Yb3+ concentration is suggested for future attempts to achieve room temperature Yb3+, Ho3+ upconversion green laser operation of these crystals

    Neodymium-Doped Sr-5(Po4)(3)F And Sr-5(Vo4)(3)F

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    Neodymium-doped Sr-5(PO4)(3)F [neodymium strontium fluoride phosphate, (Nd,Sr)(5)(PO4)(3)F] and neodymium-doped Sr-5(VO4)(3)F [neodymium strontium fluoride vanadate, (Nd,Sr)(5)(VO4)(3)F] crystallize in space group P6(3)/m and are isostructural with calcium fluorophosphate, Ca-5(PO4)(3)F. There are two different Sr sites in Sr-5(XO(4))(3)F, denoted Sr(1) and Sr(2). Using single-crystal X-ray diffraction the two structures were refined to R factors of 2.3 and 2.2%, respectively, showing that Nd is present at both Sr sites in (Sr,Nd)(5)(VO4)(3)F but only at the Sr(2) site in (Sr,Nd)(5)(PO4)(3)F

    Site-Selective Spectroscopy And Crystal-Field Analysis For Nd3+ In Strontium Fluorovanadate

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    Site‐selective spectroscopy reveals that Nd3+ ions occupy more than 40 different crystal‐field environments in Sr5(VO4)3F. Preferential energy transfer to the site responsible for 1 μm lasing occurs but becomes less complete with increasing temperature. The 4I and 4F3/2 Stark levels of the lasing site have been determined and an analysis of the crystal field performed. From the crystal‐field fitting parameters Bkq, a calculated energy‐level spectrum is determined up to 17 500 cm−1 with a rms deviation from the available experimental levels of 6 cm−1

    Efficient Laser Performance Of Ndgdlif4: A New Laser Crystal

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    Laser action of Nd3+ doped GdLiF4 (GLF) has been demonstrated for both pulsed and cw laser pumped operation. A slope efficiency of 60% was obtained in either manner of operation. The spectroscopic properties and laser performance of Nd:GLF are very similar to those of Nd:YLF. GLF, on the other hand, can be doped with much higher Nd3+ concentration

    Research in the Restricted Problems of Three and Four Bodies Final Scientific Report

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    Seven studies have been conducted on research in the existence and nature of solutions of the restricted problems of three and four bodies. The details and results of five of these research investigations have already been published, and the latest two studies will be published shortly. A complete bibliography of publications is included in this report. This research has been primarily qualitative and has yielded new information on the behavior of trajectories near the libration points in the Earth-Moon-Sun and Sun-Jupiter-Saturn systems, and on the existence of periodic trajectories about the libration points of the circular and elliptical restricted four-body models. We have also implemented Birkhoff's normalization process for conservative and nonconservative Hamiltonian systems with equilibrium points. This makes available a technique for analyzing stability properties of certain nonlinear dynamical systems, and we have applied this technique to the circular and elliptical restricted three-body models. A related study was also conducted to determine the feasibility of using cislunar periodic trajectories for various space missions. Preliminary results suggest that this concept is attractive for space flight safety operations in cislunar space. Results of this research will be of interest to mathematicians, particularly those working in ordinary differential equations, dynamical systems and celestial mechanics; to astronomers; and to space guidance and mission analysts

    Spectroscopy And Green Up-Conversion Laser-Emission Of Er(3+)-Doped Crystals At Room-Temperature

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    The spectroscopic parameters of Er3+-doped crystals were determined with regard to the upconversion laser parameters of the green transition S-4(3/2) -- \u3e I-4(15/2), The influence of excited-state absorption on this laser channel was determined. Furthermore, upconversion pump mechanisms using ground-state and excited-state absorption around 810 and 970 nm were investigated by direct measurements of excited-state absorption. The spectroscopic results confirm the pulsed room-temperature laser experiments on the S-4(3/2) -- \u3e I-5(5/2) transition. The lasers based on Er:LiYF4, Er:Y3Al5O12, and Er:Lu3Al5O12 were directly excited into the upper laser level by an excimer laser pumped dye laser in the blue spectral range. In Er:LiYF4, Er:KYF4, and Er:Y3Al5O12, laser action was achieved with two-step upconversion pumping by a Ti:sapphire laser and a krypton ion laser. In the case of the fluorides, the additional pumping with the krypton ion laser was not necessary. The laser emission wavelengths were 551 nm for Er:LiYF4, 561 nm for Er:Y3Al5012 and Er:Lu3Al5O12, and 562 nm for Er:KYF4. In addition, green quasi-cw laser emission of Er:LiYF4 pumped with an argon-ion laser was realized at room temperature
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