• Korean Journal of Mathematics
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• v.10 no.2
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• pp.173-177
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• 2002

The purpose of this paper is to study and characterize the flows of characteristic 0. It is shown that the homomorphic image of distal flow of characteristic 0 is a distal flow of characteristic 0. It is also shown that the closure of every orbit in a 0-graphic flow is regular minimal.

• Korean Journal of Mathematics
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• v.11 no.2
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• pp.161-167
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• 2003

The purpose of this paper is to study and characterize the notions of characteristic 0 and weakly almost periodicity in flows. In particular, we give sufficient conditions for the weakly almost periodic flow to be almost periodic.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.10
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• pp.1282-1289
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• 2019

In order to measure the transfer characteristic(S21) of the impedance transformer, two impedance transformers must be symmetrically connected. However, the transfer characteristic of two symmetrically connected impedance transformers is influenced by the length of the intermediate connection line. This paper theoretically examines closely the length of the intermediate connection line to obtain the accurate transfer characteristic of the impedance transformer. The electrical length of the intermediate connection line for obtaining the accurate transfer characteristic of the 4:1(50-Ω:12.5-Ω) impedance transformer is calculated about 45°. Using the calculated length of the connection line, The λ/4-microstrip impedance transformer is fabricated at 1 GHz to measure the transfer characteristic. The symmetrically connected impedance transformer is measured the reflection characteristic(S11) of -40.64dB and the transfer characteristic(S21) of -0.154dB at 0.980GHz. This value is approximately equal to the theoretical calculated 987MHz center frequency and -0.15dB transfer loss value of the λ/4-microstrip impedance transformer.

• Journal of the Korean Ceramic Society
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• v.31 no.2
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• pp.185-193
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• 1994

Effect of Sb2O3 addition on microstructure and the PTCR characteristic was investigated. The range of the Sb2O3 content and the sintering temperature showing semiconducting and PTCR characteristic, were 0.05~0.125 mol%, and over 130$0^{\circ}C$, respectively. We found that PTCR characteristic, that is, room-temperature resistivity and specific resistivity ration were dependent on the microstructure.

• Journal of the Korean Mathematical Society
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• v.51 no.4
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• pp.867-879
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• 2014

It is known that the orbifold Euler characteristic $e_{orb}(S)$ of a log del Pezzo surface S of rank one satisfies the inequality $0{\leq}e_{orb}(S){\leq}3$. In this note, we show that the orbifold Euler characteristic of S is strictly positive, i.e., 0 < $e_{orb}(S)$. Moreover, we also show, by construction, the existence of log del Pezzo surfaces of rank one with arbitrarily small orbifold Euler characteristic.

• Journal of Korea Water Resources Association
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• v.36 no.4
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• pp.533-545
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• 2003

This study analyzed several storm events observed in the Seolma-chun basin to derive the characteristic velocity of GIUH (Geomophological Instantaneous Unit Hydrograph) as well as its variability. Especially, this study focused on the variation of characteristic velocity due to the change of rainfall characteristics. The IUH of the Seolma-chun basin was derived using the HEC-1, whose peak discharge and time were then compared with those of the GIUH to derive the characteristic velocities. The characteristics velocities were analyzed by comparing with the GcIUH (Geomorphoclimatic IUH) as well as the characteristics of rainfall. Results are summarized as follows. (1) The characteristic velocity of GIUH was estimated higher with higher variability than the GcIUH, but their trends were found similar (2) Total amount of effective rainfall (or, mean effective rainfall) well explains the characteristic velocity of GIUH. This could be assured by the regression analysis, whose coefficient of determination was estimated about 0.6. (3) The duration and the maximum intensity of rainfall were found not to affect significantly on the characteristic velocity of GIUH. The coefficients of determination were estimated less than 0.3 for all cases considered. (4) For the rainfall events used in this study, the characteristic velocities of GIUH were found to follow the Gaussian distribution with its mean and the standard deviation 0.402 m/s and 0.173 m/s, respectively. Most of the values are within the range of 0.4∼0.5 m/s, and its coefficient of variation was estimated to be 0.43, much less than that of the runoff itself (about 1.0).

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1752-1754
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• 1998

Recently the research about electron transport characteristic and energy distribute function in mixture gases within Helium, has been used and developed widely as industrial quality improvement of extinguish characteristic, electrical dielectric strength ability of application of each species high voltage apparatus, gas plasma etching progress of work to use manufacture of semiconductor, thin film molding by CVD, insulation film to use ultra LSI, etc. This paper analyze electron transport characteristic in the range E/N $1{\sim}60$[Td], pressure $0.1{\sim}6.0$[Torr] by MCS. It is necessary to seek electron drift velocity, diffusion coefficient, lonization coefficients, characteristic energy, mean energy and electron energy distribution function as electron transport characteristic.

• Journal of the Korean Ceramic Society
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• v.42 no.5 s.276
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• pp.314-318
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• 2005

The effect of reaction parameters in the characteristic of $Pb(Zr_{0.52}Ti_{0.48})O_3$ (below nominal PZT) powders by SHS was investigated in this study. In the preparation of PZT, the effect of starting material contents, pressure, additive on phase fraction and morphology was investigated respectively. The optimum condition of PZT powders were prepared by SHS is $0.37Pb_3O_4+0.52ZrO_2+0.48TiO_2+0.35KClO_3+0.5C,\;(P_{Ar}= 50 atm)$. The PZT powder synthesized in this condition had an spherical shape and the particle size of 0.8$\mu$m.

• Journal of Software Assessment and Valuation
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• v.15 no.1
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• pp.109-114
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• 2019

In this paper, simulations of S-parameter and characteristic impedance for the probe pin are performed and its high-frequency performance is analyzed. The probe pins are arranged with one signal pin in the center and four ground pins on the top, bottom, left and right sides. The insertion loss and return loss of the probe pin are calculated while increasing the separation between the probe pins to 0.35 mm, 0.40 mm, and 0.50 mm, respectively. It is confirmed that the probe pin has different features of the insertion loss due to its periodic resonance phenomenon. Effect of the characteristic impedance on pitch and assignment of the probe pin is also analyzed. It is verified that there are a number of ground pins whose characteristic impedance is close to 50 Ω.

• The Journal of Korean Physical Therapy
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• v.14 no.3
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• pp.407-417
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• 2002

The purpose of this study was to examine the influence of general characteristic of the patient with low back pain on the psychologic Status. The Questionnaires was done for 312 persons with low back pain who live in Daejeon. The study was conducted between 1st, June and 26th, July in 2000. The results were as follows: 1. The effects of general characteristic of the patient with low back pain on the psychologic Status were related age(p<0.01), education level(p<0.01), job(p<0.01), husband and wife existence(p<0.01), disease(p<0.01). 2. The influence of an item on Handler score was related the reason of pain(r=0.377, p<0.01), the site and pattern of pain(r=0.314, p<0.01), the influence of climate(r=0.370, p<0.01), the frequency of pain(r=0.396, p<0.01), the position of producible pain(r=0.411, p<0.01), one's desire(r=0.394, p<0.01), experience of pessimism(r=0.421, p<0.01).