• Journal of the Korean Physical Society
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• v.73 no.9
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• pp.1385-1392
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• 2018

A network with coupled biological neurons provides various forms of collective synchronous dynamics. Such phase-locking dynamics states resemble eigenvectors in a linear coupling system in that the forms are determined by the symmetry of the coupling strengths. However, the states behave as attractors in a nonlinear dynamics system. We here study the collective synchronous dynamics in a neural system by using a novel theory. We exhibit how the period and the stability of individual phase-locking dynamics states are determined by the characteristics of synaptic couplings. We find that, contrary to common sense, the firing rate of a synchronized state decreases with increasing synaptic coupling strength.

• Computers and Concrete
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• v.19 no.6
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• pp.659-666
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• 2017

Based on the Arrhenius equations, several hydration exothermic models that precisely calculate the influence of concrete's self-temperature duration on its hydration exothermic rate have been presented. However, the models' convergence is difficult to achieve when applied to engineering projects, especially when the activation energy of the Arrhenius equation is precisely considered. Thus, the models' convergence performance should be improved. To solve this problem and apply the model to engineering projects, the relationship between fast iteration and proper expression forms of the adiabatic temperature rise, the coupling relationship between the pipe-cooling and hydration exothermic models, and the influence of concrete's self-temperature duration on its mechanical properties were studied. Based on these results, the rapid convergence of the hydration exothermic model and its coupling with pipe-cooling models were achieved. The calculation results for a particular engineering project show that the improved concrete hydration exothermic model and the corresponding mechanical model can be suitably applied to engineering projects.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.924-925
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• 2008

There are many types of grid-connected inverter controllers, PI controller based is the most popular methods. But, a common PI control is produced zero-steady state error and phase delay in sinusoidal reference. Synchronous reference frame or DQ transform based controller is capable for reducing both of zero-steady state error and phase delay is. But DQ transform based controller has cross-coupling component which difficult to analyze the system in single phase model. In this paper, to obtained single phase model of the system, DQ transform based controller is analyzed in two techniques. The first is by neglecting cross-coupling. The second is eliminated cross-coupling component by decoupling method. By these two techniques, single phase model is obtained. Then, the single phase model is analyzed to evaluate its performance in stability and frequency response, through Root Locus and Bode diagram, respectively. MATLAB and PSIM simulation is used to verify the analysis. Simulation result is shown; cross-coupling component has no significant influent to the controller.

• Atmosphere
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• v.31 no.2
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• pp.171-183
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• 2021

The sensitivity of the extratropical jet to the stratospheric mean state is investigated by conducting a series of idealized numerical experiments using a dynamic-core general circulation model. When the polar stratosphere is forced to be cold, the extratropical jet, defined by the 850-hPa zonal wind, tends to shift poleward without much change in its intensity. The opposite is also true when the polar stratosphere becomes warm. This jet response, however, is not exactly linear. A poleward jet shift under a cold vortex is much weaker than an equatorward jet shift under a warm vortex. The jet intensity change is also larger under a warm vortex. This result indicates that the stratosphere-troposphere downward coupling is more efficient for the warm and weak polar vortex. This finding is consistent with a stronger downward coupling during stratospheric sudden warming than vortex intensification events in the Northern Hemisphere winter, possibly providing a clue to better understand the observed stratosphere-troposphere downward coupling.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.7
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• pp.205-217
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• 2022

The purpose of this study was to explore the relationship between agricultural insurance, agricultural loans, and the agricultural industry and find ways to consolidate and improve the interactive development between these three systems. We collected relevant data from 2009 to 2019 in 15 provinces of China and constructed a coupled coordination model to analyze the data. The results are as follows: First, the eastern part of China was ahead of the central and western parts in terms of agricultural loans and the agricultural industry, while the western part was ahead of the central and eastern parts in terms of agricultural insurance. Second, the coupling degree of the three systems in all 15 provinces reached an extremely high level. Third, all 15 provinces showed an overall continuous rise in coupling coordination degree. In 2019, eight provinces reached the medium-level coupling coordination development, and seven provinces were in a state of barely coupling coordination development. The three systems formed a mutually reinforcing relationship and basically entered a state of coordinated development. Finally, there was a great development gap between different regions of China concerning the coordinated development of the three systems, therefore, innovative development is urgently needed to further promote the coordinated development level.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.10.1-10.1
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• 2008

• Smart Structures and Systems
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• v.20 no.1
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• pp.53-60
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• 2017

Reinforced concrete shear wall is one of the most common structural forms for high-rise buildings, and seismic energy dissipation techniques, which are effective means to control structural vibration response, are being increasingly used in engineering. Reinforced concrete-mild steel damper stiffness-tandem energy dissipation coupling beams are a new technology being gradually adopted by more construction projects since being proposed. Research on this technology is somewhat deficient, and this paper investigates design principles and methods for two types of mild steel dampers commonly used for energy dissipation coupling beams. Based on the conception design of R.C. shear wall structure and mechanics principle, the basic design theories and analytic expressions for the related optimization parameters of dampers at elastic stage, yield stage, and limit state are derived. The outcomes provide technical support and reference for application and promotion of reinforced concrete-mild steel damper stiffness-tandem energy dissipation coupling beam in engineering practice.

• Journal of the Optical Society of Korea
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• v.12 no.3
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• pp.192-195
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• 2008

We report on the spatial information of a coupling laser transfer into a reflected probe laser; the transfer is achieved by means of electromagnetically induced transparency through a common excited state connected with $5S_{1/2}-5P_{1/2}(F=1{\rightarrow}F'=2)$ in the $^{87}Rb\;D_1$ line. When the coupling laser was spatially modulated as a stationary wave, the absorption of the probe laser was enhanced and the reflection of the probe laser was generated. When the coupling laser was spatially modulated by a mask, we observed that the reflection light of the probe laser was modulated as the shape of the mask. The Bragg reflection transferred the spatial information of the coupling laser. The reflection was approximately 7% of the incident power of the probe laser.

• Bulletin of the Korean Chemical Society
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• v.18 no.9
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• pp.976-981
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• 1997

The magnetic susceptibilities of molybdenum ions with 4d1 electronic configuration in the octahedral crystal field were calculated on the basis of ligand field theory. The experimental magnetic susceptibilities for molybdenum ions, which are stabilized at the octahedral site in the perovskite lattice of Ba2ScMoⅤO6 and Sr2YMoⅤO6, were compared with the theoretical ones. We have tried to fit their temperature dependence of magnetic susceptibility with ligand field parameters, spin-orbit coupling constant ζSO, and orbital reduction parameter κ according to intermediate field coupling and strong field theory. Strong field coupling theory could not explain experimental curves without unrealistically large axial ligand field, since it ignores the mixing up between different state via spin-orbit interaction and ligand field. On the other hand, the intermediate field coupling theory could successfully reproduce experimental data in octahedral and trigonal ligand field. The fitting result demonstrates not only the fact that spin-orbit interaction is primarily responsible for the variation of magnetic behavior but also the fact that effective orbital overlap, enhanced by cubic crystal structure, reduces significantly orbital angular momentum as indicated by κ parameter.

• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.421-428
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• 1998

The effect of silane coupling agents on the water stability of HAC/PVA based MDF cement composites which were modified with urethane and epoxy resin were studied as a function of the functional groups and addition amount of silane coupling agent. According to the composition of polymer matrix the silanes with different functional groups showed the different effectiveness. In case of the only PVA matrix the silane with vinyl functional group was more effective than other silanes. When the epoxy resin was added the silane of epoxy-methodxy group enhanced the flexural strength of dry and wet state more than other. In case of urethane-added MDF cement the silane of diamine group was effective and enhanced the water sta-bility fo MDF cement composite more and more as the addition amount of silane increased, Especially in case of warm-presed composite the effect of silane was enhanced By addition of 2wt% of silane with 야-amine group the flexural strength of urethane-added composites were enhanced by 20% more in dry state 40-70% in wet state in accord with the porosity analysis. The flexural strength of the poxy resin-added MDF cement composite was increased by addition of 1wt% and 2wt% silane of epoxy-methoxy group However the addition of 4wt% of silane decreased the flexural strength of dry and wet state by formation of closed pore in the polymer matrix.