243 research outputs found

    Governing environmental conflicts in China: Under what conditions do local government compromise?

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    In recent years, governing environmental conflicts concerning the planning, construction, and operation of urban facilities has increasingly become a challenge for Chinese local governments. Chinese governments seek adequate responses to deal with these conflicts, for instance by ignoring criticism and sticking to initial decisions, by suppressing protests, or by compromising. In this article, by analysing 10 conflict cases in China using crisp-set qualitative comparative analysis (csQCA), we aim to investigate which combinations of diverse conditions lead to changes in local governments’ decisions. Four contextualized paths to explain both the presence and the absence of these changes are identified. These findings increase our understanding of the mechanisms underlying the governance of environmental conflicts in China and may inform Chinese governments and non-state actors seeking ways to deal adequately with them

    Synthesis and electronic properties of Ruddlesden-Popper strontium iridate epitaxial thin films stabilized by control of growth kinetics

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    We report on the selective fabrication of high-quality Sr2_2IrO4_4 and SrIrO3_3 epitaxial thin films from a single polycrystalline Sr2_2IrO4_4 target by pulsed laser deposition. Using a combination of X-ray diffraction and photoemission spectroscopy characterizations, we discover that within a relatively narrow range of substrate temperature, the oxygen partial pressure plays a critical role in the cation stoichiometric ratio of the films, and triggers the stabilization of different Ruddlesden-Popper (RP) phases. Resonant X-ray absorption spectroscopy measurements taken at the Ir LL-edge and the O KK-edge demonstrate the presence of strong spin-orbit coupling, and reveal the electronic and orbital structures of both compounds. These results suggest that in addition to the conventional thermodynamics consideration, higher members of the Srn+1_{n+1}Irn_nO3n+1_{3n+1} series can possibly be achieved by kinetic control away from the thermodynamic limit. These findings offer a new approach to the synthesis of ultra-thin films of the RP series of iridates and can be extended to other complex oxides with layered structure.Comment: 7 pages, 6 figure

    Transport properties and anisotropy in rare earth doped CaFe2As2 single crystals with Tc above 40 K

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    In this paper we report the superconductivity above 40 K in the electron doping single crystal Ca1-xRexFe2As2 (Re = La, Ce, Pr). The x-ray diffraction patterns indicate high crystalline quality and c-axis orientation. the resistivity anomaly in the parent compound CaFe2As2 is completely suppressed by partial replacement of Ca by rare earth and a superconducting transition reaches as high as 43 K, which is higher than the value in electron doping FeAs-122 compounds by substituting Fe ions with transition metal, even surpasses the highest values observed in hole doping systems with a transition temperature up to 38 K. The upper critical field has been determined with the magnetic field along ab-plane and c-axis, yielding the anisotropy of 2~3. Hall-effect measurements indicate that the conduction in this material is dominated by electron like charge carriers. Our results explicitly demonstrate the feasibility of inducing superconductivity in Ca122 compounds via electron doping using aliovalent rare earth substitution into the alkaline earth site, which should add more ingredients to the underlying physics of the iron-based superconductors.Comment: 21 pages, 7 figure

    Low-temperature synthesis of SmFeAsO0.7F0.3 wires with high transport critical current density

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    Ag-sheathed SmFeAsO0.7F0.3 (Sm-1111) superconducting wires were prepared by a one-step solid state reaction at temperatures as low as 850~900C, instead of commonly used temperatures of 1150~1250C. The X-ray diffraction pattern of the as-sintered samples is well indexed on the basis of tetragonal ZrCuSiAs-type structure. We characterized transport critical current density Jc of the SmFeAsO0.7F0.3 wires in increasing and subsequently decreasing fields, by a resistive four-probe method. A transport Jc as high as ~1300 A/cm^2 at 4.2 K and self field has been observed for the first time in Sm-1111 type polycrystalline superconductors. The Jc also shows a rapid depression in small applied fields as well as a magnetic-history dependence, indicating weak-linked grain boundaries. The low-temperature synthesis method can be very beneficial to fabricating the RE-1111 iron oxynictides in a convenient and safe way.Comment: 12 pages, 3 figure

    Governing Environmental Conflicts in China

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    Governing Environmental Conflicts in China

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    Toward a Commonly Shared Public Policy Perspective for Analyzing Risk Coping Strategies

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    The concept of risk has received scholarly attention from a variety of angles in the social, technical, and natural sciences. However, public policy scholars have not yet generated a comprehensive overview, shared understanding and conceptual framework of the main problem-solving approaches applied by governments in coping with risks. In this regard, our main aim is to examine existing perspectives on prevailing risk coping strategies, find a common denominator among them and contribute to current policy and risk science literature through providing a conceptual framework that systematically spans the spectrum of risk coping strategies and incorporates the essence of the most relevant insights. To this end, we first examine the concept of risk in-depth by exploring various definitions and types of risk. We then review different approaches proposed by different strands of research for addressing risk. Finally, we assess current knowledge and develop an amalgamated perspective for examining how risks can be addressed by classifying them into six general types of response (no response; prevention; control; precaution; toleration; and adaptation) as well as indicators to identify these responses. We argue that these strategies can function as a heuristic tool fo

    Equivalent Circuit of Metamaterial Formed by Array of Conductive Disks

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    The use of metamaterials to obtain a wideband wide angle impedance matching (WAIM) for compact phased array of interconnected crossed rings is investigated. The metamaterial layer above the planar array is formed by array of conductive disks in contrast to the conventional multilayer homogeneous dielectric structure. The equivalent circuit of the metamaterial layer to enhance wideband array antenna design is derived based on a hybrid technique. The values of the components in the equivalent circuit to represent metamaterial layer is given. The response from the equivalent circuit is verified by using the full-wave numerical simulations on the metamaterial structure. The results show the effectiveness of the method in analyzing the electromagnetic characteristics of the structure and improving the performance of the whole array system

    In-House Made Inverted Microstrip Line Phase Shifter Based on Nematic Liquid Crystal

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    Nematic liquid crystals are anisotropic dielectrics whose properties could be controlled by surface anchoring, exter-nal electric or magnetic fields. A typical design method of tunable inverted microstrip line phase shifter based on liquid crystal for microwave application is investigated. Two phase shifter designs based on the proposed method were introduced with the center operation frequency of 10 GHz and 20 GHz respectively. The prototype design operating at 20GHz is manufactured. The dielectric anisotropy of the liquid crystal used for the prototype is 0.45. A differential phase shift of 27.2° was achieved at 20 GHz with the physical length of 20 mm, connected to two coplanar waveguide ports of 50 ohms through vias, and under an external bias of 7 V

    Analysis of Airflow Uniformity in Pig Nurseries Using Duct Ventilation in Northeast China

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    The problem of uneven ventilation in pig houses must be solved to effectively improve the winter environmental quality of pig nurseries in cold regions. In this study, the airflow field and airflow uneven coefficients of pig nurseries with duct ventilation were simulated and calculated using computational fluid dynamics, and compared with pig nurseries with different duct diameters, inlet and outlet air velocities and air supply angles. The average relative error between the simulated and measured values was 12%. Comparison of simulation results and airflow uneven coefficients showed that the airflow uneven coefficients of the fences were reduced, and the airflow field was uniformly distributed with a duct diameter of 0.3 m, inlet and outlet air velocities of 1.5 and 2.0 m/s, respectively, and an air supply angle of 45°. These improvements resulted in a more homogeneous ventilation, which led to more uniform ventilation and contributed to discharging dirty air outdoors. Then the test pig nursery was modified based on the simulation and analysis results. Difference analyses were carried out between the control and the test pig nurseries. Comparative analyses showed the differences between the test data and the monitoring data were smaller, and the duct ventilation was more uniform, which was suitable for the healthy growth of piglets.OPEN ACCESS Received: 19/07/2024 Accepted: 10/10/202
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