• 아시안잔디학회지
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• 제18권3호
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• pp.119-128
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• 2004

This study was conducted to analyze the effect of roof membrane on light environment that influence on turfgrass growth under domed stadium. Roof structure on experimental plot was constructed with PTFE and PE same as Busan Asiad Main Stadium. Tested turfgrass species were combinations of cool-season grasses(Kentucky Bluegrass, perennial ryegrass, $KBG80+PR20\%,\;KBG33+PR33+Fine fescue33\%)$ and warm-season grasses(zoysiagrass, 'An-yang middle-leaf, 'Zenith', Bermudagrass) established with seeding or sodding. The experimental set-up and research work were initiated November 1999 and finished on August 2000 at near Busan Asiad Main Stadium. By the result of computer simulation of daylight radiant energies on the turf surface were lower than needs of normal sport turf growth. The shortage of radiant resulted pest infection on cool-season grass mixture compared with warm-season. But turf color and density showed the best results on Kentucky bluegrass or its mixture plot. Over all the results showed that the best quality of turfgrass growth was occurred on full sun area, and the next was under PTFE membrane. The application of artificial lighting system may increase the turfgrass growth under domed stadium(partially) covered with roof membrane.

• Radiation Oncology Journal
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• 제2권2호
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• pp.221-228
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• 1984

The recogition that the vast majority of patients with small cell lung cancer have distant metastatic disease at the time of diagnosis lead to the use of systemic chemotherapy and consequent major improvement in survival, but recently evaulated treatment strategies, integration of large field chest irradiation with chemotherapy lead to the improved the local control and relapse free survival in limited SCLC. Therefore, it is logical to combine the two modalities in an effort to maximize the therapeutic effect. Authors performed the combination chemotherapy of CAV (Cyclophosphamide, Adriamycin, an6 Vincristine) and radiotherapy of primary tumor and regional lymphatics with prophylatic cranial irradiation in 42 patients of limited SCLC, from Mar. 1978 to Dec. 1982 Seoul National University Hospital. The results are as follows : 1. CR and PR after 2 cycles chemotherapy is $7\%$ and $43\%$, respectively however, subsequent response to radiotherapy is $38\%$ and $43\%$ in CR and PR. 2. Overall median survival peroid is 8.6 months. 3. 1 year and 2 years survival rate is $46.3\%$ and $20.5\%$, respectively. 4. Incidence of proven brain metastasis is $5\%$.

• 한국세라믹학회지
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• 제42권5호
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• pp.299-303
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• 2005

The crystal structure and ferroelectricity of the $(1-x)BiFeO_3\;(BF)-xPbTiO_3$ (PT) ceramic system with the addition of $DyFeO_3$ (DF) have been investigated for attaining a high temperature piezoelectric material. This study is focused on the relation between crystal structure and ferroelectric property with the addition of DF over the phase boundary in the (1-x)BF-xPT system. Hysteresis curves of polarization-electric field at room temperature have been measured. The X-ray and neutron diffraction data were analyzed by the rietveld refinement method. The addition of 0.1 mole DF into BF-PT system greatly increases the ferroelectric remanant polarization Pr values, e.g. 17 ${\mu}C/cm^2$ in 0.6BF-yDF-(0.4-y)PT and 31${\mu}C/cm^2$ in 0.5BF-yDF-(0.5.y)PT, respectively. The improved Pr value has been discussed in relation with crystal structure and electrical property.

• 한국위성정보통신학회논문지
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• 제3권2호
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• pp.18-25
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• 2008

A major drawback of Orthogonal Frequency Division Multiplexing (OFDM) system is high peak-to-average power ratio (PAPR) of the transmitted signal which introduces inevitable non-linear distortion in the transmission due to the amplifier non-linear property. This causes both in-band distortion and out of band spectrum re-growth. A polynomial based pre-distortion is estimated using the non-linear and inverse non-linear polynomial achieved through the Least Square Error (LSE) method. A new technique of PAPR reduction called 'Phase Realignment' (PR) is proposed which has a optimal effect in improving the BER performance as well as considerable reduction in the PAPR. In this paper we used the PR method along with the 'Peak Clipping' (PC) method is used before the pre-distortion to remove the high peak present in the non constant amplitude of the OFDM signal responsible to drive the amplifier in near saturation region for better performance of the system.

• 한국전산유체공학회지
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• 제16권3호
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• pp.29-36
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• 2011

The natural convection in a horizontal enclosure heated from the bottom wall, cooled at the top wall, and having a square adiabatic body at its centered area was studied. Three different Prandtl numbers (0.01, 0.7 and 7) were considered for an effect of the Prandtl number on natural convection. A two-dimensional solution for unsteady natural convection was obtained, using Chebyshev spectral methodology for different Rayleigh numbers varying over the range of $10^4$ to $10^6$. It had been experimentally and numerically reported [1,2] that the heat transfer mode becomes oscillatory when Pr is out of a specific Pr band beyond the critical Ra. In this study, we reproduced this phenomenon numerically. The variation of time- and surface-averaged Nusselt numbers on the hot and cold walls for different Rayleigh numbers and Prandtl numbers was presented to show the overall heat transfer characteristics in the system. And also, the isotherms and streamline distributions were presented in detail to compare the physics related to their thermal behavior.

• 한국전기전자재료학회논문지
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• 제13권7호
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• pp.551-556
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• 2000

We have investigated the effect of surface In composition with Si cell temperature on the In$_{0.1}$/Ga$_{0.9}$/As epilayers grown on GaAs substrates. The epilayers were grown by molecular beam epitaxy(MBE) method and were characterized by the pthotoreflectance(PR) measurements. The E$_{o}$ bandgap energies of In$_{0.1}$/Ga$_{0.9}$/As epilayers were observed at around 1.28 eV at room temperature, and the additional shoulder peaks appeared at the higher energies than E$_{o}$ with increase of Si doping concentrations. The intensity of the additional shoulder peak was decreased with lowering the measurement temperature and the peak disappeared with the increase of surface etching time. This results hows that In composition at surface of InGaAs epilayer is decreased with the increase of the doping cell temperature. We consider that the reason of the decrease of In composition at the surface should be due to In re-evaporation from the surface by radiation heat of Si doping cell.ell.ell.ell.

• 한국전기전자재료학회논문지
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• 제17권11호
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• pp.1167-1173
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• 2004

This paper reports the variations of varistor voltage, nonlinear exponent, leakage current, and dissipation factor against surge stress of ZnO-P $r_{6}$ $O_{11}$-CoO-C $r_2$ $O_3$-E $r_2$ $O_3$(ZPCCE)-based varistors manufactured with the variations of sintering temperature. It was found that the variations of electrical parameters against surge stressing current of 100 A/$\textrm{cm}^2$(8x20 ${\mu}\textrm{s}$) is not so large under the surge stress of 700 times. Among varistors, specially the varistor sintered at 134$0^{\circ}C$ exhibited the smallest variations, with %$\Delta$ $V_{lmA}$=+0.23%, %$\Delta$$\alpha$=+0.23%, %$\Delta$ $I_{L}$=0%, %$\Delta$tan$\delta$=-6.94%. The clamping voltage ratio( $V_{c}$/ $V_{lmA}$) of all varistors was less than 2.2.2.2.2.2.2.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.319-320
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• 2006

In order to improve the ESD(Electrical Static Discharge) resistance of multilayer chip varistors, we have investigated ZnO-$Pr_6O_{11}$ based chip varistor by applying tape casting technology, whose fundamental component were ZnO : $Pr_6O_{11}$ :$Co_3O_4$: $Y_2O_3$: $Al_2O_3$=93.67: 2.53:2.53:1.25 : 0.015 (wt %). The effect of sintering condition on the multilayer chip varistors and electric properties was studied. The electrical properties and ESD resistance of multilayer chip varistor could be influenced the sintering temperature and condition.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2007년도 제32회 학술대회 초록집
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• pp.149-149
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• 2007

• Bulletin of the Korean Chemical Society
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• 제17권10호
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• pp.892-899
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• 1996

In order to elucidate the effect of alkoxy substituent in thexylborane and hence establish their usefulness as hydroborating agent, reactions of alkenes and alkynes with thexylalkoxyborane (ThxBHOR; R=Et, i-Pr, i-Bu, sec-Bu, t-Bu, Ph) were investigated in detail. The reagents readily hydroborated alkenes and alkynes of various structural types at 25 ℃ in excellent regioselectivity. The selectivity increases consistently with increasing steric size of alkoxy substituent. Especially, the selectivity achieved by the sec-butoxy derivative is comparable to that previously achieved by thexylhaloborane-methyl sulfide (ThxBHX·SMe2), the most selective hydroborating agent known.