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Search Results: 1 - 10 of 68620 matches for " Gang Yang "
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Fine Root Mortality Increased by Earthquake Induced Landslides  [PDF]
Yinping Bai, Gang Yang
Open Journal of Earthquake Research (OJER) , 2016, DOI: 10.4236/ojer.2016.53014
Abstract: This study determined the effects of earthquake induced landslide on fine root mortality. It is useful to understand underground soil process after earthquake. We established 9 plots at each of non-moved and landslide site in Cupressus funebris and Cryptomeria fortunei forest stands near the fault belt of the Wenchuan Earthquake. Fine roots were sampled at 0 - 10 and 10 - 15 cm soil layer using aluminum cylinders (100 cm3). We found that earthquake induced landslide significantly increased fine root mortality in Cupressus funebris and Cryptomeria fortunei forest stands. Fine root biomass also decreased by landslide at 0 - 10 cm soil layer. We observed that the fine root biomass and mortality were various with forest type. There were higher fine root mortality rate (68.4%) and lower fine root biomass (0.48 t/hm2) in Cupressus funebris than the Cryptomeria fortunei soils (0.97 t/hm2 and 37.4%).
Existence and Uniqueness of Solutions to Impulsive Fractional Integro-Differential Equations with Nonlocal Conditions  [PDF]
Zhenghui Gao, Liu Yang, Gang Liu
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.46118
Abstract: In this article, by using Schaefer fixed point theorem, we establish sufficient conditions for the existence and uniqueness of solutions for a class of impulsive integro-differential equations with nonlocal conditions involving the Caputo fractional derivative.
Thermo-Dynamical Analysis on Electricity-Generation Subsystem of CAES Power Plant  [PDF]
Wenyi Liu, Gang Xu, Yongping Yang
Journal of Power and Energy Engineering (JPEE) , 2014, DOI: 10.4236/jpee.2014.24097
Abstract:

Besides pumped hydropower, Compressed Air Energy Storage (CAES) is the other solution for large energy storage capacity. It can balance fluctuations in supply and demand of electricity. CAES is essential part of smart power grids. Linked with the flow structure and dynamic characteristic of electricity generation subsystem and its components, a simulation model is proposed. Thermo-dynamical performance on off-design conditions have been analyzed with constant air mass flux and constant gas combustion temperature. Some simulation diagrams of curve are plotted too. The contrast of varied operation mode thermal performance is made between CAES power plant and simple gas turbine power plant.

ACTA MATHEMATICA UNIVERSITATIS COMENIANAE
Zhao Liang and Yang Gang
ACTA MATHEMATICA UNIVERSITATIS COMENIANAE , 2007,
Abstract: . Let R be a ring. We introduce weakly reversible rings, which are a generalization of reversible rings, and investigate their properties. Moreover, we show that a ring R is weakly reversible if and only if for any n, the n-by-n upper triangular matrix ring Tn(R) is weakly reversible. Also some kinds of examples needed in the process are given.
On Weakly Reversible Rings
Zhao Liang,Yang Gang
ACTA MATHEMATICA UNIVERSITATIS COMENIANAE , 2007,
Abstract: Let R be a ring. We introduce weakly reversible rings, which are a generalization of reversible rings, and investigate their properties. Moreover, we show that a ring R is weakly reversible if and only if for any n, the n-by-n upper triangular matrix ring Tn(R) is weakly reversible. Also some kinds of examples needed in the process are given.
An Algorithm for Quantitatively Calculating I/Q Gain and Phase Mismatch
Gang Yang,Jin Liu
TELKOMNIKA : Indonesian Journal of Electrical Engineering , 2012, DOI: 10.11591/telkomnika.v10i4.872
Abstract: The in-phase and quadrature modulator (IQ modulator) is a key component in modern wireless transmitter. It provides a convenient method for modulating data bits or symbols onto an RF carrier. It has become the architecture of choice for implementing transmitter signal chains for end applications such as cellular, WiMAX, and wireless point-to-point. However, there are several non-ideal aspects of analog IQ modulator, include IQ gain imbalance, imperfect quadrature, and LO leakage. These imperfections will result in image spectral and degrade MER of the modulator, which in turn degrades bit error rate (BER). Gain matching and phase compensation both affect the total amount of image rejection. Factory calibration can detect the IQ gain and phase mismatch in different frequency and store the correction coefficients in nonvolatile memory. The key issue is how to get the exact mismatch. In this paper, a mathematical model of IQ modulator was established and an analytic solution is obtained about how to get the exact mismatch parameters.
Analysis of Microsatellite DNA Markers Reveals no Genetic Differentiation between Wild and Hatchery Populations of Pacific Threadfin in Hawaii
Gang Pan, Jinzeng Yang
International Journal of Biological Sciences , 2010,
Abstract: Pacific threadfin, Polydactylus sexfilis, is popular fish in recreational fishing, as well as aquaculture in Hawaii. Its natural population has been continuously declining in the past several decades. Microsatellite DNA markers are useful DNA-based tool for monitoring Pacific threadfin populations. In this study, fifteen Microsatellite (MS) DNA markers were identified from a partial genomic Pacific threadfin DNA library enriched in CA repeats, and six highly-polymorphic microsatellite loci were employed to analyze genetic similarity and differences between the wild population and hatchery population in Oahu Island. A total of 37 alleles were detected at the six MS loci in the two populations. Statistical analysis of fixation index (FST) and analysis of molecular variance (AMOVA) showed no genetic differentiation between the wild and hatchery populations (FST=0.001, CI95%= -0.01-0.021). Both high genetic diversity (Ho=0.664-0.674 and He=0.710-0.715) and Hardy-Weinberg equilibrium were observed in the wild and hatchery populations. Results of genetic bottleneck analysis indicated that the hatchery was founded with sufficient numbers of brooders as inbreeding coefficient is very low (FIS=0.052-0.072) in both wild and hatchery populations. Further studies are needed for comprehensive determinations of genetic varieties of primary founder broodstocks and successive offspring of the hatchery and wild populations with increased number of Pacific threadfin sample collections.
Itinerant Flat-Band Magnetism in Hydrogenated Carbon Nanotubes
Xiaoping Yang,Gang Wu
Physics , 2010,
Abstract: We investigate the electronic and magnetic properties of hydrogenated carbon nanotubes using ab initio spin-polarized calculations within both the local density approximation (LDA) and the generalized gradient approximation (GGA). We find that the combination of charge transfer and carbon network distortion makes the spin-polarized flat-band appear in the tube's energy gap. Various spin-dependent ground state properties are predicted with the changes of the radii, the chiralities of the tubes and the concentration of hydrogen (H). It is found that strain or external electric field can effectively modulate the flat-band spin-splitting, and even induce an insulator-metal transition.
The study of structure, electronic and optical properties of double-walled carbon nanotube bundle under hydrostatic pressure
Xiaoping Yang,Gang Wu
Physics , 2008, DOI: 10.1209/0295-5075/81/47003
Abstract: Combining a classical force field, a tight-binding model, and first-principles calculations, we have studied structural, electronic, and optical properties of double-walled carbon nanotube (DWNT) bundles under hydrostatic pressure. We find that the outer tube acts as a protection shield for the inner tube and the inner tube increases the structure stability and the ability to resist the pressure of the outer tube. Moreover, the collapsed structures of the double-walled carbon nanotube bundle called ``parallel'' and ``in-between'' are more stable than the one called ``herringbone''. The structural phase transition induces a pseudogap along symmetry line \textit{$\Gamma $X}. Furthermore, the optical properties change greatly after the collapse and a strong anisotropy appears in the collapsed structure. This provides an efficient experimental way to detect structural phase transitions in DWNT bundles.
Simulations of the spatial and temporal invariance in the spectra of gradual solar energetic particle events
Yang Wang,Gang Qin
Physics , 2015,
Abstract: The spatial and temporal invariance in the spectra of energetic particles in the gradual solar events is reproduced in the simulations. Based on a numerical solution of the focused transport equation, we obtain the intensity time profiles of solar energetic particles (SEPs) accelerated by an interplanetary shock in the three-dimensional interplanetary space. The shock is treated as a moving source of energetic particles with a distribution function. The time profiles of particle flux with different energies are calculated in the ecliptic at $1$ AU. According to our model, we find that shock acceleration strength, parallel diffusion and adiabatic cooling are the main factors in forming the spatial invariance in SEP spectra, and perpendicular diffusion is a secondary factor. In addition, the temporal invariance in SEP spectra is mainly due to the effect of adiabatic cooling. Furthermore, a spectra invariant region, which agrees with observations but is different than the one suggested by Reames and co-workers, is proposed based on our simulations.
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