An assessment of wetland nature reserves and the protection of China’s vertebrate diversity

Evaluación de los humedales declarados reserva natural y protección de la diversidad de vertebrados de China Se evaluaron las reservas naturales existentes en China y se estudió la distribución de los cuatro taxones de vertebrados terrestres endémicos y amenazados, que comprenden los reptiles, los anfibios, las aves y los mamíferos. Con vistas a determinar la riqueza de las especies, se combinó la evaluación anterior de los 148 humedales declarados reserva natural con la lista de los vertebrados endémicos y amenazados elaborada por el gobierno. Dicha riqueza de especies se clasificó en tres categorías: alta, media y baja mediante un análisis factorial y se seleccionaron 31 ecosistemas de humedales como zonas de alta protección. Asimismo, se analizó la relación existente entre las especies amenazadas y las endémicas en las reservas, y se observó que ambos modelos de riqueza eran parecidos. Se espera que, sobre la base del estudio de la riqueza, se pueda crear un sistema de clasificación de las reservas naturales, con su gestión correspondiente, con el objetivo de proteger la diversidad de las especies en China.We assessed all 148 wetland nature reserves in China and the distribution of the four taxa of endemic and threatened terrestrial vertebrates, reptiles, amphibians, birds and mammals. Assessment of the wetland nature reserves was combined with the governmental list of the endemic and threatened vertebrates to identify the richness of the species. Species richness was scored as high, medium or low using a factor analysis method, and 31 wetland ecosystems were marked as high protection areas. The relationship between the threatened species and the endemic species in the reserves was also analyzed. We found that both richness patterns were similar. Based on the richness study, a nature reserve classification system with correspondingEvaluación de los humedales declarados reserva natural y protección de la diversidad de vertebrados de China Se evaluaron las reservas naturales existentes en China y se estudió la distribución de los cuatro taxones de vertebrados terrestres endémicos y amenazados, que comprenden los reptiles, los anfibios, las aves y los mamíferos. Con vistas a determinar la riqueza de las especies, se combinó la evaluación anterior de los 148 humedales declarados reserva natural con la lista de los vertebrados endémicos y amenazados elaborada por el gobierno. Dicha riqueza de especies se clasificó en tres categorías: alta, media y baja mediante un análisis factorial y se seleccionaron 31 ecosistemas de humedales como zonas de alta protección. Asimismo, se analizó la relación existente entre las especies amenazadas y las endémicas en las reservas, y se observó que ambos modelos de riqueza eran parecidos. Se espera que, sobre la base del estudio de la riqueza, se pueda crear un sistema de clasificación de las reservas naturales, con su gestión correspondiente, con el objetivo de proteger la diversidad de las especies en China

Improved Simulation of the Mass Charging for ASTROD I

The electrostatic charging of the test mass in ASTROD I (Astrodynamical Space Test of Relativity using Optical Devices I) mission can affect the quality of the science data as a result of spurious Coulomb and Lorentz forces. To estimate the size of the resultant disturbances, credible predictions of charging rates and the charging noise are required. Using the GEANT4 software toolkit, we present a detailed Monte Carlo simulation of the ASTROD I test mass charging due to exposure of the spacecraft to galactic cosmic-ray (GCR) protons and alpha particles (3He, 4He) in the space environment. A positive charging rate of 33.3 e+/s at solar minimum is obtained. This figure reduces by 50% at solar maximum. Based on this charging rate and factoring in the contribution of minor cosmic-ray components, we calculate the acceleration noise and stiffness associated with charging. We conclude that the acceleration noise arising from Coulomb and Lorentz effects are well below the ASTROD I acceleration noise limit at 0.1 mHz both at solar minimum and maximum. The coherent Fourier components due to charging are investigated, it needs to be studied carefully in order to ensure that these do not compromise the quality of science data in the ASTROD I mission.Comment: 20 pages, 14 figures, submitted to International Journal of Modern Physics

Design and implementation of an amorphous high-frequency transformer coupling multiple converters in a smart microgrid

© 1982-2012 IEEE. Recent improvements in magnetic material characteristics and switching devices have generated a possibility to replace the electrical buses with high-frequency magnetic links in microgrids. Multiwinding transformers (MWTs) as magnetic links can effectively reduce the number of conversion stages of renewable energy system by adjusting turn ratio of windings according to the source voltage level. Other advantages are galvanic isolation, bidirectional power flow capability, and simultaneous power transfer between multiple ports. Despite the benefits, design, and characterization of MWTs are relatively complex due to their structural complexity and cross-coupling effects. This paper presents all stages of numerical design, prototyping, and characterization of an MWT for microgrid application. To design the transformer for certain value of parameters, the reluctance network method is employed. Due to the iterative nature of transformer design, it presented less computation time and reasonable accuracy. A prototype of designed transformer is implemented using amorphous magnetic materials. A set of experimental tests are conducted to measure the magnetic characteristics of the core and series coupling and open-circuit tests are applied to measure the transformer parameters. A comparison between the simulation and experimental test results under different loads within the medium-frequency range validated both design and modeling procedures

Nuclear pairing reduction due to rotation and blocking

Nuclear pairing gaps of normally deformed and superdeformed nuclei are investigated using the particle-number conserving (PNC) formalism for the cranked shell model, in which the blocking effects are treated exactly. Both rotational frequency $\omega$-dependence and seniority (number of unpaired particles) $\nu$-dependence of the pairing gap $\tilde{\Delta}$ are investigated. For the ground-state bands of even-even nuclei, PNC calculations show that in general $\tilde{\Delta}$ decreases with increasing $\omega$, but the $\omega$-dependence is much weaker than that calculated by the number-projected Hartree-Fock-Bogolyubov approach. For the multiquasiparticle bands (seniority $\nu> 2$), the pairing gaps keep almost $\omega$-independent. As a function of the seniority $\nu$, the bandhead pairing gaps $\tilde{\Delta}(\nu,\omega=0)$ decrease slowly with increasing $\nu$. Even for the highest seniority $\nu$ bands identified so far, $\tilde{\Delta}(\nu,\omega=0)$ remains greater than 70% of $\tilde{\Delta}(\nu=0,\omega=0)$.Comment: 15 pages, 5 figure

Role of semicore states in the electronic structure of group-III nitrides: An exact exchange study

The bandstructure of the zinc-blende phase of AlN, GaN, InN is calculated employing the exact-exchange (EXX) Kohn-Sham density-functional theory and a pseudopotential plane-wave approach. The cation semicore d electrons are treated both as valence and as core states. The EXX bandgaps of AlN and GaN (obtained with the Ga 3d electrons included as core states) are in excellent agreement with previous EXX results, GW calculations and experiment. Inclusion of the semicore d electrons as valence states leads to a large reduction in the EXX bandgaps of GaN and InN. Contrary to common belief, the removal of the self-interaction, by the EXX approach, does not account for the large disagreement for the position of the semicore d electrons between the LDA results and experiment.Comment: 10 pages including 3 figures; related publications can be found at http://www.fhi-berlin.mpg.de/th/th.htm

Kondo effect and anti-ferromagnetic correlation in transport through tunneling-coupled double quantum dots

We propose to study the transport through tunneling-coupled double quantum dots (DQDs) connected in series to leads, using the finite-$U$ slave-boson mean field approach developed initially by Kotliar and Ruckenstein [Phys. Rev. Lett. {\bf 57}, 1362 (1986)]. This approach treats the dot-lead coupling and the inter-dot tunnelling $t$ nonperturbatively at arbitrary Coulomb correlation $U$, thus allows the anti-ferromagnetic exchange coupling parameter $J=4t^2/U$ to appear naturally. We find that, with increasing the inter-dot hopping, the DQDs manifest three distinct physical scenarios: the Kondo singlet state of each dot with its adjacent lead, the spin singlet state consisting of local spins on each dot and the doubly occupied bonding orbital of the coupled dots. The three states exhibit remarkably distinct behavior in transmission spectrum, linear and differential conductance and their magnetic-field dependence. Theoretical predictions agree with numerical renormalization group and Lanczos calculations, and some of them have been observed in recent experiments.Comment: 5 pages, 5 figures. Physics Review B (Rapid Communication) (in press

WHW_H-pair Production in the Littlest Higgs Model with T parity in next-to-leading order QCD at LHC

In the framework of the littlest Higgs model with $T$ parity, we study the $W_H$-pair production at the CERN Large Hadron Collider up to the QCD next-to-leading order (NLO). The kinematic distributions of final decay products and the theoretical dependence of the cross section on the factorization/renormalization scale are analyzed. We adopt the PROSPINO scheme in the QCD NLO calculations to avoid double counting and keep the convergence of the perturbative QCD description. Our numerical results show that the QCD NLO corrections significantly reduce the scale uncertainty, and enhance the leading order integrated cross section with a $K$-factor in the range of $1.10-1.22$ ($1.09-1.17$) with the symmetry breaking scale $f$ varying from $400 GeV$ ($400 GeV$) to $1.5 TeV$ ($1.0 TeV$) at the $14 TeV$ $(8 TeV)$ LHC. We find that it is possible to select the signal events of the $W_H$-pair production from the $pp\to W^+ W^- \to e^+ \mu^-\nu_{e}\bar{\nu}_{\mu}+X$ background with high ratio of signature over background by taking proper lower limits on transverse momenta, invariant mass of the final charged leptons and the missing transverse momentum.Comment: 34 pages, 14 figures, 4 table

Effect of the Kondo correlation on thermopower in a Quantum Dot

In this paper we study the thermopower of a quantum dot connected to two leads in the presence of Kondo correlation by employing a modified second-order perturbation scheme at nonequilibrium. A simple scheme, Ng's ansatz [Phys. Rev. Lett. {\bf 76}, 487 (1996)], is adopted to calculate nonequilibrium distribution Green's function and its validity is further checked with regard to the Onsager relation. Numerical results demonstrate that the sign of the thermopower can be changed by tuning the energy level of the quantum dot, leading to a oscillatory behavior with a suppressed magnitude due to the Kondo effect. We also calculate the thermal conductance of the system, and find that the Wiedemann-Franz law is obeyed at low temperature but violated with increasing temperature, corresponding to emerging and quenching of the Kondo effect.Comment: 6 pages, 4 figures; accepted for publication in J Phys.: Condensed Matte