• 한국지구과학회지
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• 제37권7호
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• pp.389-397
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• 2016

${\delta}$ Scuti형 변광성 BO Lyn의 파장에 따른 광도곡선 차이를 알아보기 위해서 보현산천문대의 1.8m 반사망원경과 적외선 검출기 KASINICS를 이용한 측광 관측을 수행하였다. 2011년 3월 26일부터 4월 1일까지 총 7일간의 관측 자료로 J, H, Ks필터 광도곡선을 얻어 기존에 보고된 V필터에서의 광도곡선과 비교하여 주기, 극대점, 진폭, 형태에 대한 차이를 알아보았다. 적외선 광도곡선의 주기 분석 결과 단일 주파수해 $f_1=10.712cycle/day$, 주기$P=0.09335{\pm}0.00002days$의 값을 얻었으며, 파장에 따른 주기의 차이는 나타나지 않았다. 적외선에서는 $2f_1$에 해당하는 주파수가 검출되었는데, 이는 고진폭 ${\delta}$ Scuti형 변광성의 특징인 비대칭적인 광도곡선의 형태를 잘 설명해준다. 극대점의 위치를 비교한 결과 계산된 V필터의 예상 극대점보다 관측된 적외선 극대점이 전체 주기의 약 0.3에 해당하는 만큼 더 늦게 나타났다. 진폭은 ${\Delta}J/{\Delta}V=0.328$, ${\Delta}H/{\Delta}V=0.216$, ${\Delta}Ks/{\Delta}V=0.211$로 파장이 길어질수록 변광의 폭이 더 작게 나타났다. 파장에 따른 극대점의 지연과 변광폭의 차이는 맥동변광성의 밝기 변화가 주로 온도변화에 기인하기 때문인 것으로 여겨진다.

• 한국의류산업학회지
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• 제10권4호
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• pp.566-571
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• 2008

Frictional sounds of 8 vapor permeable water repellent fabrics by sound generator were recorded and analyzed through FFT fast Fourier transform analysis. The frictional Sounds were quantified by calculating level pressure of total sound(LPT), the level range(${\Delta}L$) and the frequency difference(${\Delta}f$). Mechanical properties were measured by KES-FB. LPT values of specimens finished wet coating were higher than those of other kinds of finishing. ${\Delta}L$ values of specimens laminated were highest. Absolute values of ${\Delta}f$ were high in the cire finished and laminated specimens. Values for bending rigidity, shear stiffness and energy required for the compression of coated specimens increased compared with the cire finished and laminated specimens. Laminated specimens had high values of frictional coefficient and low values of surface roughness. Relationship between frictional sounds and mechanical properties analysed by use of correlation coefficients and stepwise regression. LPT showed significant correlation with elongation, tensile energy, geometrical roughness, weight and thickness. ${\Delta}L$ was highly correlated with tensile linearity, frictional coefficient, and ${\Delta}f$ with tensile linearity, weight and thickness. LPT were revealed to be explained by elongation and weight. ${\Delta}L$were predicted by tensile linearity, and ${\Delta}f$ by tensile linearity and thickness.

• 대한설비공학회지:설비저널
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• 제8권3호
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• pp.131-150
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• 1979

Recently only a few correlations between various factors due to the different grades of surface roughness for the nucleate pool boiling have been proposed. The main purpose of this work is to test the validity of these types of correlations between related factors to nucleate pool boiling phenomena. The boiling experiments using distilled water were carried out at the heat flux ranging from $7.4\times10^4\;to\;2.4\times10^5kcal/m^2h$ on the sintered porous metal surface with the cavity diameter of 10, n, 40, 70, $100{\mu}$, respectively, at the atmospheric pressure, To determine the bubble sizes, number of nucleation sites, delay and growth time, frequency of bubble emission and rising velocities of bubbles, the high speed motion picture technique was employed. In the correlation $f{\propto}D_b^n$, where f denotes frequency of bubble emission and $D_b$ departure diameter, n, the power factor of $D_b$, have been found to be from -2 to -10/3. The correlation C in the correlation between heat flux q and density of nucleation sites $\frac{N}{A}$, $q=C(\frac{N}{A})^n$, was appeared to be more crucial than the power factor n. The correlation of the heat flux q to the temperature difference ${\Delta}T$ and the density of nucleation sites$\frac{N}{A}$, was proposed to be $$q-460{\Delta}T^{\frac{5}{4}}=K{\Delta}T{\frac{5}{3}}(\frac{N}{A})^{\frac{2}{3}}$$. The values of heat transfer coefficient obtained in this experiments for the porous sintered metal surface appeared to be very high in comparison with the formerly obtained results for the other surfaces.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2003년도 춘계학술대회 논문집
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• pp.8-13
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• 2003

Frictional sound of 13 vapor permeable water repellent fabric by sound generator were recorded and analysed through FFT analysis. The frictional Sounds were quantified by calculating total sound pressure(LPT), the level range ΔL and the frequency difference Δf. Mechanical properties were measured by KES-FB. LPT values of specimens finished wet coating were higher than those of dry coating. Values for bending rigidity, shear stiffness, surface roughness and compressional recovery of polyurethane fabrics increased compared with the cire finished fabrics. Laminated fabrics had high values of frictional coefficient and low values of surface roughness. LPT showed significant correlation with compressional energy, weight and thickness. (ΔL) was highly correlated with compressional linearity, frictional coefficient, compressional recovery, and (Δf) with tensile linearity, compressional energy, thickness, and weight.

• 한국대기환경학회지
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• 제12권4호
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• pp.369-376
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• 1996

Major atmospheric stability classification methods were evaluated with meteorological data obtained by scoustic sounding profiler (SODAR/RASS) in Seoul. The Psequill classificatio method, the method most widely used because of its good agreement in respect of synoptic scope under the steady state, fails to describe the time lag, the response time on stability by heating or cooling caused by daily insolation or noctrunal surface radiation. Horizontal and vertical standard deviation of wind fluctuation $(\sigma_A and \sigma_E)$ method tend to classify night-time stable condition (E, F class) into unstable condition (A, B class). The classification matrix tables for Vogt's vertical temperature difference and wind speed using method ($\Delta$T $\cdot$ U) and bulk Richardson number (Rb) were amended for practical use over Seoul. The modified tables for $\Delta$T $\cdot$ U and Rb method were made by using comprehensive frequency distribution from Pasquill's method and other existing results, and the correlation coefficient(r) was equal to 0.829. It was confirmed that atmospheric stability could be changed with monitoring site characteristics, height and vertical difference between sensors of monitoring station, and classification method itself.

• 천문학회보
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• 제41권1호
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• pp.41.1-41.1
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• 2016

We present the physical properties of KIC 6220497 exhibiting multiperiodic pulsations from the Kepler photometry. The light curve synthesis represents that the eclipsing system is a semi-detached Algol with a mass ratio of q=0.243, an orbital inclination of i=77.3 deg, and a temperature difference of ${\Delta}T=3,372K$, in which the detached primary component fills its Roche lobe by ~87% and is about 1.6 times larger than the lobe-filling secondary. To detect reliable pulsation frequencies, we analyzed separately the Kepler light curve at the interval of an orbital period. Multiple frequency analyses of the eclipse-subtracted light residuals reveal 32 frequencies in the range of $0.75-20.22d^{-1}$ with semi-amplitudes between 0.27 and 4.55 mmag. Among these, four frequencies ($f_1$, $f_2$, $f_5$, $f_7$) may be attributed to pulsation modes, while the other frequencies can be harmonic and combination terms. The pulsation constants of 0.16-0.33 d and the period ratios of $P_{pul}/P_{orb}=0.042-0.089$ indicate that the primary component is a ${\delta}$ Sct pulsating star in p modes and, thus, KIC 6220497 is an oscillating eclipsing Algol (oEA) star. The dominant pulsation period of about 0.1174 d is considerably longer than the values given by the empirical relations between the pulsational and orbital periods. The surface gravity of log $g_1=3.78$ is significantly smaller than those of the other oEA stars with similar orbital periods. The pulsation period and the surface gravity of the pulsating primary demonstrate that KIC 6220497 would be the more evolved EB, compared with normal oEA stars.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.233-237
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• 1991

In the study, samples were made on the electrode in internal glass bell jar by the radio frequency discharge polymerization. The polymerization rate of samples was observed as a function of r.f. discharge power. The characteristics of polymers obtained from TMDSO and HMDSO were analyzed by FT-IR and TGA, and their electrical properties were examined on insulation resistivity, breakdown voltage, dielectric constant, and tan ${\delta}$. (1) There was no difference between PPTMDSO and PPHMDSO in a polymerization rate and thermal and electrical properties. (2) The growing rates of thin film with discharge powers were from $0.42{\mu}/h$ to $1.2{\mu}m/h$. (3) According to IR spectra analysis, discharge power did not effect polymer structure due to polyermization mechanism and effected only polymerization rate. (4) PPTMDSO and PPHMDSO were thermally resistive polymers which did not decompose to $300^{\circ}C$.

• Asian-Australasian Journal of Animal Sciences
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• 제20권3호
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• pp.340-350
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• 2007

The objective of this study was to determine whether peroxisome proliferator-activated receptor ${\gamma}$(PPAR${\gamma}$ is involved in the regulation of weaning to estrus of primiparous sows. Twelve sows composed of 6 groups of 2 full-sibs in a similar age (325.2 d), body weight (BW; 152.4 kg) and backfat thickness (BFT; 27.0 mm) at start of lactation, were allocated to accept 31 MJ (restricted group, R-group) or 53 MJ (control group, C-group) DE/d treatment, respectively. The experimental results indicated that the low energy intake resulted in excessive losses of BW and BFT during lactation in R-group sows, which may be related to decrease of serum 15-deoxy-${\Delta}^{12,14}$-prostaglandin $J_2$ (15d-$PGJ_2$), a ligand of PPAR${\gamma}$ The obvious peak and the frequency of LH, FSH and estradiol ($E_2$) were only observed in C-group sows. Except for $E_2$ at d 1 and 2, serum FSH, LH and $E_2$ concentrations in R-group were lower than those in C-group sows after weaning. However, the serum progesterone ($P_4$) level in R-group sows was always more than that in C-group. The expression abundances of PPAR${\gamma}$and GnRH receptor (GnRH-R) in pituitary, FSH receptor (FSH-R), LH receptor (LH-R), estrogen receptor (ES-R) and aromatase in ovary of anestrous sows were lower than those of estrous sows. Neither the BFT nor the BW was associated with the mRNA abundance of PPAR${\gamma}$in hypothalamus during lactation. Expressions of PPAR${\gamma}$in pituitary and ovary were affected evidently by the BFT changes and only by the loss of BW of sows during and after lactation. Furthermore, PPAR${\gamma}$mRNA level in ovary was significantly related to the expression abundances of GnRH-R, FSH-R, ES-R and aromatase, and GnRH-R was obviously associated with PPAR${\gamma}$expression in pituitary. However, PPAR${\gamma}$expression in hypothalamus likely has no effects on these genes expression and no obvious difference for all sows. Not serum $E_2$ or $P_4$ alone but the ratios of $E_2$ to $P_4$ and 15d-$PGJ_2$ to $P_4$, and serum FSH and LH were evidently related to PPAR${\gamma}$expression in pituitary and ovary. It is concluded that PPAR${\gamma}$is associated with body conditions, reproduction hormones and their receptor expression, which affected the functions of pituitary and ovary and ultimately the estrus after weaning of primiparous sows.