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Search Results: 1 - 10 of 134367 matches for " Gang Li "
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Hidden charmonium decays of $Z_c$ in intermediate meson loops model
Li, Gang
High Energy Physics - Phenomenology , 2013,
Abstract: The BESIII collaboration reported an observation of a charged charmonium-like structure $Z_c(3900)$ in the invariant mass spectrum of $J/\psi \pi^{\pm}$ in $e^+ e^- \to J/\psi \pi^+\pi^-$ at the center of mass 4.260 MeV, which could be an analogue of $Z_b(10610)$ claimed by the Belle Collaboration. In this work, we investigate the hidden charmonium transitions of $Z_c$ via intermediate $D \ {D}^*$ meson loops. Our results show that the intermediate $D \ {D}^*$ meson loops are crucial for driving the transitions of $Z_c$. We also make a predication for the hidden charmonium decays of $Z_c$'s partner ($Z_c^\prime$).
Research on the Competency-Based Teaching Mode of Human Resources Management
Gang Li
Economic Management Journal , 2013,
Abstract: Human resources management is one of new modern management subjects emphasizing the practice and application. The traditional teaching mode cannot meet the ability training objectives of the major of human resources management. According the goals of competency training for the major of human resources management, the paper puts forward the competency-based teaching mode.
Hidden physics in the dual-fermion approach - a special case of a non-local expansion scheme
Gang Li
Physics , 2014, DOI: 10.1103/PhysRevB.91.165134
Abstract: In this work, we present a nonlocal expansion scheme to study correlated electron systems aiming at a better description of its spatial fluctuations at all length scales. Taking the nonlocal coupling as a perturbation to the local degrees of freedom, we show that the nonlocality in the self-energy function can be efficiently constructed from the coupling between local fluctuations. It can provide one unified framework to incorporate nonlocality to both ordered and disordered correlated many-body fermion systems. In this application, we prove that the dual-fermion approach can be understood as a special case of this nonlocal expansion scheme. The scheme presented in this work is constructed without introducing any dual variable, in which the interacting nature and the correlated behaviors of the lattice fermions have a clear physics correspondence. Thus, in this special case, the equivalence of the dual-fermion approach to the nonlocal expansion scheme beautifully reveals the physics origin of the dual variables. We show that the noninteracting dual-fermion Green's function corresponds exactly to a nonlocal coupling of the lattice fermion renormalized by the local single-particle charge fluctuations, and the dual-fermion self-energy behaves as the one-particle fully irreducible components of the lattice Green's function. Not only limited to this specific example, the nonlocal expansion scheme presented in this work can also be applied to other problems depending on the choice of the local degrees of freedom.
Kondo lattice model: from local to non-local descriptions
Gang Li
Physics , 2013,
Abstract: In this paper, we study the influence of spatial fluctuations in a two-dimentional Kondo-Lattice model (KLM) with anti-ferromagnetic couplings. To accomplish this, we first present an implementation of the dual-fermion (DF) approach based on the hybridization expansion continuous-time quantum Monte Carlo impurity solver (CT-HYB), which allows us to consistently compare the local and non-local descriptions of this model. We find that, the inclusion of non-locality restores the self-energy dispersion of the conduction electrons, {\it i.e.} the $\vec{k}$ dependence of $\Sigma(\vec{k}, i\omega_{n})$. The anti-ferromagnetic correlations result in an additional symmetry in $\Sigma(\vec{k}, i\omega_{n})$, which is well described by the N\'eel antiferromagnetic wave-vector. A "metal"-"anti-ferromagnetic insulator"-"Kondo insulator" transition is observed at finite temperatures, which is driven by the competition of the effective RKKY interaction (at the weak coupling regime) and the Kondo singlet formation mechanism (at the strong coupling regime). Away from half-filling, the anti-ferromagnetic phase becomes unstable against hole doping. The system tends to develop a ferromagnetic phase with the spin susceptibility $\chi_{s}(Q)$ peaking at $Q=\Gamma$. However, for small $J/t$, no divergence of $\chi_{s}(\Gamma)$ is really observed, thus, we find no sign of long-range ferromagnetism in the hole-doped two-dimension KLM. The ferromagnetism is found to be stable at larger $J/t$ regime. Interestingly, we find the local approximation employed in this work, {\it i.e.} the dynamical mean-field theory (DMFT), is still a very good description of the KLM, especially in the hole-doped case. However, at half-filling, the non-local fluctuation effect is indeed pronounced. We observe a strong reduction of the critical coupling strength for the onset of the Kondo insulating phase.
Constant Q-curvature metrics near the Hyperbolic metric
Gang Li
Mathematics , 2012,
Abstract: Let $(M,\,g)$ be a Poincar$\acute{\text{e}}$-Einstein manifold with a smooth defining function. In this note, we prove that there are infinitely many asymptotically hyperbolic metrics with constant $Q$-curvature in the conformal class of an asymptotically hyperbolic metric close enough to $g$. These metrics are parametrized by the elements in the kernel of the linearized operator of the prescribed constant $Q$-curvature equation. A similar analysis is applied to a class of fourth order equations arising in spectral theory.
A compactness theorem on Branson's $Q$-curvature equation
Gang Li
Mathematics , 2015,
Abstract: Let $(M, g)$ be a closed Riemannian manifold of dimension $5$. Assume that $(M, g)$ is not conformally equivalent to the round sphere. If the scalar curvature $R_g\geq 0$ and the $Q$-curvature $Q_g\geq 0$ on $M$ with $Q_g(p)>0$ for some point $p\in M$, we prove that the set of metrics in the conformal class of $g$ with prescribed constant positive $Q$-curvature is compact in $C^{4, \alpha}$ for any $0 <\alpha < 1$. We also give some estimates for dimension $6$ and $7$.
Mobile Positioning System Based on the Wireless Sensor Network in Buildings  [PDF]
Xiujun LI, Gang SUN, Xu WANG
Communications and Network (CN) , 2009, DOI: 10.4236/cn.2009.12015
Abstract: Established on the Intel Multi-Core Embedded platform, using 802.11 Wireless Network protocols as the communication medium, combining with Radio Frequency-Communication and Ultrasonic Ranging, imple-ment a mobile terminal system in an intellectualized building. It can provide its holder such functions: 1) Accurate Positioning 2) Intelligent Navigation 3) Video Monitoring 4) Wireless Communication. The inno-vative point for this paper is to apply the multi-core computing on the embedded system to promote its com-puting speed and give a real-time performance and apply this system into the indoor environment for the purpose of emergent event or rescuing.
How hypertensive patients in the rural areas use home blood pressure monitoring and its relationship with medication adherence: A primary care survey in China  [PDF]
Huanhuan Hu, Gang Li, Takashi Arao
Open Journal of Preventive Medicine (OJPM) , 2013, DOI: 10.4236/ojpm.2013.39069
Abstract:

Despite an increasing popularity of home blood pressure monitoring (HBPM) over the last few decades, little is known about HBPM use among hypertensive patients in the rural areas. A cross-sectional survey including 318 hypertensive patients was conducted in a rural community in Beijing, China, in 2012. Participants were mainly recruited from a community health clinic and completed the questionnaires assessing HBPM usage. Binary logistic regression models were used for the analysis of medication adherence with age, gender, level of education marital status, perceived health status, duration of hypertension, HBPM use, and frequency of performing BP measurement. Among the total population, 78 (24.5%) reported currently use of HBPM. Only 5.1% of the HBPM users cited doctor’s advice as the reason for using HBPM. Analysis of the risk factors of poor medication adherence by multivariable modeling indicated significant associations between the duration of hypertension (adjusted OR, 3.31; 95% CI, 1.91-5.72; P < 0.001), frequency of performing BP measurements (adjusted OR, 2.33; 95% CI, 1.42-3.83; P < 0.001) and medication adherence. We found that most use of HBPM was without the involvement of a doctor or nurse. Further study is required to understand if HBPM is effective and the role of health professionals in its use for improved hypertension control.

 

An Analysis of the Greenhouse Gas Emissions by the Re-Liquefaction of Boil-Off Gas of LNG Storage Tank  [PDF]
Gang Sun, Shengchun Liu, Xueqiang Li
Energy and Power Engineering (EPE) , 2015, DOI: 10.4236/epe.2015.78033
Abstract: The pressure in liquefied natural gas (LNG) storage tank continues to increase due to the heat transfer from ambient air to low temperature LNG, which raises safety concerns. Accordingly, there is increasing interest to explore the technical approaches capable of recovering Boil-Off Gas (BOG) and even eliminating the ventilation of LNG storage tank. This research numerically analyzed the greenhouse gas emissions of the re-liquefaction of BOG using the following four approaches: 1) a Claude cycle driven by electrical motor with the electricity produced by burning coal; 2) a Claude cycle driven by a gas turbine fuelled by BOG released; 3) a Claude cycle driven by a SI engine fuelled by gasoline; 4) burning nature gas directly released by BOG. The impact of heat transfer coefficient, LNG tank configuration, size, and percentage of LNG stored in tank on the rate of BOG and energy needed for the re-liquefaction of methane vapor were investigated. The greenhouse gas emissions (GGE) was examined and compared. The data presented in this paper provide guideline for the management of pressure development in LNG storage tank.
Investigation of airborne fungi at different altitudes in Shenzhen University  [PDF]
Li Li, Chao Lei, Zhi-Gang Liu
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.25063
Abstract: Aim: To investigate the richness of species or genera of airborne fungi, the amount of airborne fungi, and its seasonal variation at different al-titudes in Shenzhen University. The effect of meteorological factors on airborne fungi was also analyzed. Methods: Slide-exposure me- thod and open-plate method were used. Results: There were 27 genera or species of fungus spores identified. Among the identified fungal genus, Cladosporium, Ustilago, Alternaria, Helminth-sporium and Uredinales were more prevalent. There were 18 genera of fungi colonies identified. Among which Penicillium, non-sporulating fungi, Aspergillus, Saccharomyces and Cladosporium were more common. The airborne fungal spores were present in the atmosphere of Shenzhen University all year round. The peaks of airborne spores appeared during April and October, while the lowest numbers were observed during January, July and December from March 2005-Febrary 2006. The highest volumes of fungi colonies were observed during April, October and September, while the lowest numbers were de-tected during in January, July and December or May from March 2005-Febrary 2006. The meteoro-logical factors had no relationship between the total monthly spore count at 10 and 30 meter height. At 70 meter, the total spores count was negatively correlated with solar radiation. Conclusions: Most of the fungi spores decreased along with the increase of altitudes.
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