202 research outputs found

    Evaluation of ecological migrants’ adaptation to their new living area in Three-River Headwater wetlands, China

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    AbstractEcological migration is an important policy for sustainable ecosystem management, which usually relocates a large number of residents from their traditional living regions with high ecological sensitivity to other areas with low ecological sensitivity as part of the government's initiative to restore and recover seriously degraded ecosystems. Evaluation of ecological migrants’ adaptation to their new living area is essential for assessing the success of migration and directing the design and implementation of measures to improve the effectiveness of migration. In this research, the adaptation of ecological migrants to their new living area was investigated and analyzed in Three-River Headwater region, a typical and significant migration area in China. The questionnaire survey method was applied. Three many issues related to migrants’ adaptation were discussed, namely the determination of suitable migration population size, the choice of follow-up industry and the integration issue in ecological migration. The result indicated that the majority of migrants could adapt to their new living places and could live with a better life standard. In spite of this, the unsuitability for new work was the major problem for the ecological migration with 72% people unable for their new work

    Localized surface states in HTSC: Alternative mechanism of zero-bias conductance peaks

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    It is shown that the quasiparticle states localized in the vicinity of surface imperfections of atomic size can be responsible for the zero-bias tunneling conductance peaks in high-Tc superconductors. The contribution from these states can be easily separated from other mechanisms using their qualitatively different response on an external magnetic field.Comment: REVTeX, 4 pages, 2 figs; to be published in PR

    Alterations in the processing of non-drug-related affective stimuli in abstinent heroin addicts.

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    Long-term exposure to drug may alter the neural system associated with affective processing, as evidenced by both clinical observations and behavioral data documenting dysfunctions in emotional experiences and processing in drug addicts. Although many imaging studies examined neural responses to drug or drug-related cues in addicts, there have been few studies explicitly designed to reveal their neural abnormalities in processing non-drug-related natural affective materials. The present study asked abstinent heroin addicts and normal controls to passively view standardized affective pictures of positive, negative, or neutral valence and compared their brain activities with functional MRI. Compared to normal controls, addicts showed reduced activation in right amygdala in response to the affective pictures, consistent with previous reports of blunted subjective experience for affective stimuli in addicts. Furthermore, in two visual cortical areas BA 19 and 37, while the controls showed greater responses to positive pictures than to negative ones replicating literature findings, the addicts showed the opposite pattern. The results reveal a complex pattern of altered processing of non-drug-related affective materials in addicts showing both heightened and blunted neural responses in different brain regions and for different stimulus valence. The present study highlights the importance of brain imaging research on drug addicts' processing of affective stimuli in understanding disruptions in their emotion circuitry

    Relations between fusion cross sections and average angular momenta

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    We study the relations between moments of fusion cross sections and averages of angular momentum. The role of the centrifugal barrier and the target deformation in determining the effective barrier radius are clarified. A simple method for extracting average angular momentum from fusion cross sections is demonstrated using numerical examples as well as actual data.Comment: 16 REVTeX pages plus 8 included Postscript figures (uses the epsf macro); submitted to Phys. Rev. C; also available at http://nucth.physics.wisc.edu/preprint

    Spin-Polarized Transport Across an La0.7_{0.7}Sr0.3_{0.3}MnO3_{3}/YBa2_{2}Cu3_{3}O7_{7} Interface: Role of Andreev Bound States

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    Transport across an La0.7_{0.7}Sr0.3MnO_{0.3}MnO_{3}/YBa2Cu_{2}Cu_{3}OO_{7}(LSMO/YBCO),interfaceisstudiedasafunctionoftemperatureandsurfacemorphology.Forcomparison,controlmeasurementsareperformedinnonmagneticheterostructuresofLaNiO(LSMO/YBCO), interface is studied as a function of temperature and surface morphology. For comparison, control measurements are performed in non-magnetic heterostructures of LaNiO_{3}$/YBCO and Ag/YBCO. In all cases, YBCO is used as bottom layer to eliminate the channel resistance and to minimize thermal effects. The observed differential conductance re ects the role of Andreev bound states in a-b planes, and brings out for the first time the suppression of such states by the spin-polarized transport across the interface. The theoretical analysis of the measured data reveals decay of the spin polarization near the LSMO surface with temperature, consistent with the reported photoemission data.Comment: 5 pages LaTeX, 3 eps figures included, accepted by Physical Review

    Top-illuminated dye-sensitized solar cells with a room-temperature- processed ZnO photoanode on metal substrates and a Pt-coated Ga-doped ZnO counter electrode

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    We report on top-illuminated, fluorine tin oxide/indium tin oxide-free (FTO/ITO-free), dye-sensitized solar cells (DSCs) using room-temperature- processed ZnO layers on metal substrates as the working electrodes and Pt-coated Ga-doped ZnO layers (GZO) as the counter electrodes. These top-illuminated DSCs with GZO render comparable efficiency to those employing commercial FTO counter electrodes. Despite a lower current density, the top-illuminated DSCs result in a higher fill factor than conventional DSCs due to a low ohmic loss at the electrode/semiconductor interface. The effect of metal substrate on the performance of the resulting top-illuminated DSCs is also studied by employing various metals with different work functions. Ti is shown to be a suitable metal to be used as the working electrode in the top-illuminated device architecture owing to its low ohmic loss at the electrode/semiconductor interface, minimum catalytic activity on redox reactions and high resistance to corrosion by liquid electrolytes. © 2011 IOP Publishing Ltd

    Influence of impurity scattering on tunneling conductance in normal metal- d -wave superconductor junctions

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    Tunneling conductance spectra between a normal metal / d-wave superconductor junction under the presence of bulk impurities in the superconductor are studied. The quasiclassical theory has been applied to calculate the spatial variation of the pair potential and the effect of impurity scattering has been introduced by t-matrix approximation. The magnitude of a subdominant s-wave component at the interface is shown to robust against the impurity scattering while that for a subdominant dxyd_{xy}-wave component is largely suppressed with the increase of the impurity scattering rate. The zero-bias conductance peak due to the zero-energy Andreev bound states is significantly broadened for the case of Born limit impurity compared with that of unitary limit impurity.Comment: 14 pages, 5 figure

    Temperature-dependence of spin-polarized transport in ferromagnet / unconventional superconductor junctions

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    Tunneling conductance in ferromagnet / unconventional superconductor junctions is studied theoretically as a function of temperatures and spin-polarization in feromagnets. In d-wave superconductor junctions, the existence of a zero-energy Andreev bound state drastically affects the temperature-dependence of the zero-bias conductance (ZBC). In p-wave triplet superconductor junctions, numerical results show a wide variety in temperature-dependence of the ZBC depending on the direction of the magnetic moment in ferromagnets and the pairing symmetry in superconductors such as pxp_{x}, pyp_{y} and px+ipyp_{x}+ip_{y}-wave pair potential. The last one is a promising symmetry of Sr2_2RuO4_4. From these characteristic features in the conductance, we may obtain the information about the degree of spin-polarization in ferromagnets and the direction of the dd-vector in triplet superconductors

    Recent experimental results in sub- and near-barrier heavy ion fusion reactions

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    Recent advances obtained in the field of near and sub-barrier heavy-ion fusion reactions are reviewed. Emphasis is given to the results obtained in the last decade, and focus will be mainly on the experimental work performed concerning the influence of transfer channels on fusion cross sections and the hindrance phenomenon far below the barrier. Indeed, early data of sub-barrier fusion taught us that cross sections may strongly depend on the low-energy collective modes of the colliding nuclei, and, possibly, on couplings to transfer channels. The coupled-channels (CC) model has been quite successful in the interpretation of the experimental evidences. Fusion barrier distributions often yield the fingerprint of the relevant coupled channels. Recent results obtained by using radioactive beams are reported. At deep sub-barrier energies, the slope of the excitation function in a semi-logarithmic plot keeps increasing in many cases and standard CC calculations over-predict the cross sections. This was named a hindrance phenomenon, and its physical origin is still a matter of debate. Recent theoretical developments suggest that this effect, at least partially, may be a consequence of the Pauli exclusion principle. The hindrance may have far-reaching consequences in astrophysics where fusion of light systems determines stellar evolution during the carbon and oxygen burning stages, and yields important information for exotic reactions that take place in the inner crust of accreting neutron stars.Comment: 40 pages, 63 figures, review paper accepted for EPJ
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