Locate QCD Critical End Point in a Continuum Model Study

With a modified chemical potential dependent effective model for the gluon propagator, we try to locate the critical end point (CEP) of strongly interacting matter in the framework of Dyson-Schwinger equations (DSE). Beyond the chiral limit, we find that Nambu solution and Wigner solution could coexist in some area. Using the CornwallJackiw-Tomboulis (CJT) effective action, we show that these two phases are connected by a first order phase transition. We then locate CEP as the end point of the first order phase transition line. Meanwhile, based on CJT effective action, we give a direct calculation for the chiral susceptibility and thereby study the crossover.Comment: 9 pages, 7 figures; Version published in JHE

The Wigner Solution and QCD Phase Transitions in a Modified PNJL Model

By employing some modification to the widely used two-flavor Polyakov-loop extended Nambu-Jona-Lasinio (PNJL) model, we discuss the Wigner solution of the quark gap equation at finite temperature and zero quark chemical potential beyond the chiral limit, and then try to explore its influences on the chiral and deconfinement phase transitions of QCD at finite temperature and zero chemical potential. The discovery of the coexistence of the Nambu and the Wigner solutions of the quark gap equation with nonzero current quark mass at zero temperature and zero chemical potential, as well as their evolutions with temperature is very interesting for the studies of the phase transitions of QCD. According to our results, the chiral phase transition might be of first order (while the deconfinement phase transition is still a crossover, as in the normal PNJL model), and the corresponding phase transition temperature is lower than that of the deconfinement phase transition, instead of coinciding with each other, which are not the same as the conclusions obtained from the normal PNJL model. In addition, we also discuss the sensibility of our final results on the choice of model parameters

High efficiency continuous-wave Ho: LSO laser wing-pumped by the laser diode at 1.91 μm

We present a high-efficiency continuous-wave Ho: LSO laser wing-pumped by a 1.91 μm laser diode. The impact of different output transmittances on the laser output power is compared and analyzed. The optimal result was achieved with a −500-mm radius curvature and a 6% transmission output coupler. The maximum output power of the Ho: LSO laser is 7.81 W, with a slope efficiency of 44.7%, a center wavelength of 2,106.6 nm, and beam quality factors of 1.4 in the x-direction and 1.3 in the y-direction

Identification of the glycerol-3-phosphate dehydrogenase (GPDH) gene family in wheat and its expression profiling analysis under different stress treatments

Glycerol-3-phosphate dehydrogenase (GPDH) catalyses the interconversion of glycerol-3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP), and plays key roles in different developmental processes and stress responses. GPDH family genes have been previously investigated in various plant species, such as Arabidopsis, maize, and soybean. However, very little is known in GPDH family genes in wheat. In this study, a total of 17 TaGPDH genes were identified from the wheat genome, including eight cytosolic GPDHs, six chloroplastic GPDHs and three mitochondrial GPDHs. Gene duplication analysis showed that segmental duplications contributed to the expansion of this gene family. Phylogenetic results showed that TaGPDHs were clustered into three groups with the same subcellular localization and domain distribution, and similar conserved motif arrangement and gene structure. Expression analysis based on the RNA-seq data showed that GPDH genes exhibited preferential expression in different tissues, and several genes displayed altered expression under various abiotic stresses. These findings provide the foundation for further research of wheat GPDH genes in plant growth, development and stress responses

Precision calculations of Bd,s→π,KB_{d, s} \to \pi, K decay form factors in soft-collinear effective theory

We improve QCD calculations of the $B_{d, s} \to \pi, K$ form factors at large hadronic recoil by implementing the next-to-leading-logarithmic resummation for the obtained leading-power light-cone sum rules in the soft-collinear effective theory (SCET) framework. Additionally, we endeavour to investigate a variety of the subleading-power contributions to these heavy-to-light form factors at ${\cal O}(\alpha_s^0)$, by including the higher-order terms in the heavy-quark expansion of the hard-collinear quark propagator, by evaluating the desired effective matrix element of the next-to-leading-order term in the ${\rm SCET_{I}}$ representation of the weak transition current, by taking into account the off-light-cone contributions of the two-body heavy-quark effective theory matrix elements as well as the three-particle higher-twist corrections from the subleading bottom-meson light-cone distribution amplitudes, and by computing the twist-five and twist-six four-body higher-twist effects with the aid of the factorization approximation. Having at our disposal the SCET sum rules for the exclusive $B$-meson decay form factors, we further explore in detail numerical implications of the newly computed subleading-power corrections by employing the three-parameter model for both the leading-twist and higher-twist $B$-meson distribution amplitudes. Taking advantage of the customary Bourrely-Caprini-Lellouch parametrization for the semileptonic $B_{d, s} \to \pi, K$ form factors, we then determine the correlated numerical results for the interesting series coefficients, by carrying out the simultaneous fit of the exclusive $B$-meson decay form factors to both the achieved SCET sum rule predictions and the available lattice QCD results.Comment: 74 pages, 15 figure

An Electrochemical Impedance Spectroscopic Study of the Electronic and Ionic Transport Properties of Spinet LiMn2O4

Electrochemical impedance spectra (EIS) for lithium ion insertion and deinsertion in spinel LiMn2O4 were obtained at different potentials and different temperatures during initial charge-discharge cycle. The results revealed that, at intermediate degrees of intercalation, three semicircles appeared in the Nyquist diagram. This new phenomenon has been investigated through EIS measurements as a function of temperature. It has found that the high frequency semicircle and the middle to high frequency semicircle begin to overlap each other above 20 degrees C, which indicates that the high frequency compressed semicircle commonly obtained at room temperature in the literature may consist of two semicircles. This signifies that the effects of the electronic and ionic transport properties of lithium intercalation materials clearly appear as separate features in the EIS spectra at low temperatures. A new equivalent circuit that includes elements related to the electronic and ionic transport, in addition to the charge transfer process, is proposed to simulate the experimental EIS data. The change of kinetic parameters for lithium ion insertion and deinsertion in spinel LiMn2O4 as a function of potential in the first charge-discharge cycle is discussed in detail, and a modified model is proposed to explain the impedance response of the insertion materials for lithium ion batteries.National Basic Research Program of China [2009CB220102