• 한국ITS학회 논문지
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• 제7권2호
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• pp.50-55
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• 2008

본 논문에서는 단락점과 접지면 사이에 집중형 소자인 인덕터를 이용하여 안테나의 입력 임피던스와 공진주파수 모두를 선택 가능한 다중 대역 내장형 안테나를 제안하였다. 제안된 안테나의 구조는 PIFA (Planar Inverted F Antenna)구조와 반파장 로디드 라인 구조의 합성으로 전체적으로 두 개의 단락점과 하나의 급전점을 가지며 그 중 하나의 단락점을 공유한다. 설계된 안테나의 동작 주파수 대역은 PIFA 구조에서 GSM ($880\;{\sim}\;960MHz$), GPS ($1575{\pm}10MHz$)이며 반파장 로디드 라인 구조에서의 인덕터의 값을 2.2nH, 3.3nH, 4.7nH로 변화시킴에 따라 제안된 안테나는 DCS ($1710{\sim}1880MHz$), US-PCS ($1850{\sim}1990MHz$), 그리고 W-CDMA ($1920{\sim}2170MHz$) 대역에서 동작한다. 공유된 단락점에서의 인덕터 값을 1.2nH, 3.9nH, 6.8nH로 변화시킴으로서 안테나의 입력 임피던스를 변화시켰으며 집중형 소자의 추가로 생기는 안테나의 이득 변화를 최소화하기 위해 사용되는 인덕터의 값을 최대 6.8nH로 제한하였다. 제안된 안테나의 최대 이득은 GSM 대역에서 1.60dBi, GPS 대역에서 -1.16dBi DCS/US-PCS/W-CDMA 대역에서 1.41dBi로 측정되었다.

• 한국재료학회지
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• 제22권4호
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• pp.185-189
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• 2012

We report plasma-assisted molecular beam epitaxy of $In_XGa_{1-X}N$ films on c-plane sapphire substrates. Prior to the growth of $In_XGa_{1-X}N$ films, GaN film was grown on the nitride c-plane sapphire substrate by two-dimensional (2D) growth mode. For the growth of GaN, Ga flux of $3.7{\times}10^{-8}$ torr as a beam equivalent pressure (BEP) and a plasma power of 150 W with a nitrogen flow rate of 0.76 sccm were fixed. The growth of 2D GaN growth was confirmed by $in-situ$ reflection high-energy electron diffraction (RHEED) by observing a streaky RHEED pattern with a strong specular spot. InN films showed lower growth rates even with the same growth conditions (same growth temperature, same plasma condition, and same BEP value of III element) than those of GaN films. It was observed that the growth rate of GaN is 1.7 times higher than that of InN, which is probably caused by the higher vapor pressure of In. For the growth of $In_xGa_{1-x}N$ films with different In compositions, total III-element flux (Ga plus In BEPs) was set to $3.7{\times}10^{-8}$ torr, which was the BEP value for the 2D growth of GaN. The In compositions of the $In_xGa_{1-x}N$ films were determined to be 28, 41, 45, and 53% based on the peak position of (0002) reflection in x-ray ${\theta}-2{\theta}$ measurements. The growth of $In_xGa_{1-x}N$ films did not show a streaky RHEED pattern but showed spotty patterns with weak streaky lines. This means that the net sticking coefficients of In and Ga, considered based on the growth rates of GaN and InN, are not the only factor governing the growth mode; another factor such as migration velocity should be considered. The sample with an In composition of 41% showed the lowest full width at half maximum value of 0.20 degree from the x-ray (0002) omega rocking curve measurements and the lowest root mean square roughness value of 0.71 nm.

• 대한치과기공학회지
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• 제41권4호
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• pp.287-293
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• 2019

Purpose: To evaluate the accuracy of the 3D printed die models and to investigate its clinical applicability. Methods: Stone die models were fabricated from conventional impressions(stone die model; SDM, n=7). 3D virtual models obtained from the digital impressions were manufactured as a 3D printed die models using a 3D printer(3D printed die models;3DM, n=7). Reference model, stone die models and 3D printed die models were scanned with a reference scanner. All dies model dataset were superimposed with the reference model file by the "Best fit alignment" method using 3D analysis software. Statistical analysis was performed using the independent t-test and 2-way ANOVA (α=.05). Results: The RMS value of the 3D printed die model was significantly larger than the RMS value of the stone die model (P<.001). As a result of 2-way ANOVA, significant differences were found between the model group (P<.001) and the part (P<.001), and their interaction effects (P<.001). Conclusion: The 3D printed die model showed lower accuracy than the stone die model. Therefore, it is necessary to further improve the performance of 3D printer in order to apply the 3D printed model in prosthodontics.

• 대한수학회보
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• 제52권1호
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• pp.35-43
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• 2015

Let q > 1 be an odd integer and c be a fixed integer with (c, q) = 1. For each integer a with $1{\leq}a{\leq}q-1$, it is clear that the exists one and only one b with $0{\leq}b{\leq}q-1$ such that $ab{\equiv}c$ (mod q). Let N(c, q) denote the number of all solutions of the congruence equation $ab{\equiv}c$ (mod q) for $1{\leq}a$, $b{\leq}q-1$ in which a and $\bar{b}$ are of opposite parity, where $\bar{b}$ is defined by the congruence equation $b\bar{b}{\equiv}1$ (modq). The main purpose of this paper is using the mean value theorem of Dirichlet L-functions to study the mean value properties of a summation involving $(N(c,q)-\frac{1}{2}{\phi}(q))$ and Kloosterman sums, and give a sharper asymptotic formula for it.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.92-95
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• 2005

The silver photodoping effect in amorphous AsGeSeS chalcogenide thin films for holographic recording has been investigated using a HeNe laser ($\lambda$=632.8 nm). The chalcogenide films prepared in this work were thinner in comparison with the penetration depth of recording light ($d_p$=1.66 mm). The variation of the diffraction efficiency $(\eta)$ in amorphous chalcogende films exhibits a tendency, independently of the Ag photodoping. That is, n increases relatively rapidly at the beginning of the recording process, reaches the maximum $({\eta}_{max})$ and slowly decreases. In addition, the value of ${\eta}_{max}$ depends strongly on chalcogenide film thickness(d) and its peak among the films with d = 40, 80, 150, 300, and 633 nm is observed at d = 150 nm (approximately 1/2n), where n is refractive index of the chalcogenide (n=2.0). The ${\eta}$ is largely enhanced by Ag photodoping into the chalcogenides. In particular, the value of hmax in a bilayer of 10-nm-thick Ag/150-nm-thick AsGeSeS film is about 1.6%, which corresponds to ~20 times in comparison with that of the AsGeSeS film (without Ag).

• 한국초지조사료학회지
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• 제5권1호
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• pp.53-61
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• 1985

화본과(禾本科) 및 두과사료작물(荳科飼料作物)의 단파(單播)와 혼파(混播)에서 중질소(重窒素)를 시용(施用)하여 시비질소(施肥窒素)의 작물별(作物別) 건물수량(乾物收量), 총질소함량(總窒素含量), 비료유내질소율(肥料由來窒素率), 토양중(土壤中) 유효질소량 등을 조사(調査)한 결과(結果)는 다음과 같다. 1. 건물수량(乾物收量)에 대(對)한 질소시비효과는 orchardgrass에서만 높이 인정(認定)되었고 alfalfa와 birdsfoot treoil은 혼파(混播)의 경우 초기(初期)에만 인정(認定)되었다. 2. 건물수량(乾物收量)은 단파(單播)에서는 alfalfa>red clover>orchardgrass>birdsfoot trefoli의 순(順)이었고 혼파(混播)에서는 orchardgrass + alfalfa> orchardgrass + red clover> orchardgrass+birdsfoot trefoil순(順)으로 나타났다. 3. 비료유내질소율(肥料由來窒素率)는 단파(單播)에서 orchardgrass가 두과(荳科)보다 높았으나 혼파(混播)한 경우는 전구(全區) 공(共)히 두과(荳科)가 orchargrass보다 높아서 orchardgrass가 두과(荳科)로부터 시비질소(施肥窒素)보다 토양질소(土壤窒素)를 공급(供給)받는 것으로 보였다. 또한 비료유내질소율(肥料由來窒素率)은 단파시(單播時) 모든 작물(作物)에서 후기(後期)로 갈수록 작아졌으며 혼파시(混播時) orchardgrass에는 일정한 경향(傾向)이 없었다. 4. 토양중(土壤中) 유효질소량은 단파시(單播時) alfalfa>red clover> orchardgrass> birdsfoot trefoil 순(順)이었으며 혼파시(混播時)는 orchardgrass+alfalfa(3 : 7) > orchardgrass + red clover (3 : 7) > orchardgrass + alfalfa(5 : 5) > orchardgrass + birdsfoot trefoil(5 : 5) > orchardgrass + red clover (5 : 5) > orchardgrass + bidsfoot trefoil(3 : 7)의 순(順)이었다.

• 한국자동차공학회논문집
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• 제7권6호
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• pp.258-269
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• 1999

It is important to evaluate fatigue damage of in-service material in respect to assure safety and remaining fatigue life in structure and mechanical components under cyclic load . Fatigue damage is represented by mathematical modelling with crack growth rate da/dN and cycle ration N/Nf and is detected by X-ray diffraction and ultrasonic wave method etc. But this is estimated generally by single parameter but influenced by many test conditions The characteristics of it indicates fatigue damage has complex fracture mechanism. Therefore, in this study we propose that back-propagation neural networks on the basis of ration of X-ray half-value breath B/Bo, fractal dimension Df and fracture mechanical parameters can construct artificial intelligent networks estimating crack growth rate da/dN and cycle ratio N/Nf without regard to stress amplitude Δ $\sigma$.

• 동아시아식생활학회지
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• 제5권3호
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• pp.215-221
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• 1995

This study was undertaken to investigate the effect of Taraxacum herba extract on the hepatic xanthine oxidase activity as a oxygen free radical generating enzyme in vitro and in vivo. It was observed that partial purified hepatic xanthine oxidase (type O) activity was strongly inhibited by the addition of Taraxacum herba n-butanol extract in vitro. The Km value of xanthine oxidase without affecting the Vmax value for xanthine was significantly increased by the addition of ta-dase (type O) activity was significantly inhibited by the treatment of Taraxacum gerba n-butanol ex-tract for 5days(over 40mg/kg, i.p), whereas, xanthine oxidase (type D) activity was not changed by the injection of Taracacum herba n-butanol extract. Meanwhile, liver weight / body weight(%), serum alanine aminotransferase activity and hepatic lipid peroxide content in Taraxacum herba n-buta-nol extract-treated rat were not changed. These findings led us to conclude that Taraxacum herba n-butanol extract may regulate the hepatic xanthine oxidase type O activity to prevent toxic effect of oxidative stress by the oxygen free radicals.

• Kyungpook Mathematical Journal
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• 제55권3호
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• pp.641-652
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• 2015

In this paper we study the problem of normal families of meromorphic functions concerning shared values. Let F be a family of meromorphic functions in the plane domain $D{\subseteq}{\mathbb{C}}$ and n, k be two positive integers such that $n{\geq}k+1$, and let a, b be two finite complex constants such that $a{\neq}0$. Suppose that (1) $f+a(f^{(k)})^n$ and $g+a(g^{(k)})^n$ share b in D for every pair of functions f, $g{\in}F$; (2) All zeros of f have multiplicity at least k + 2 and all poles of f have multiplicity at least 2 for each $f{\in}F$ in D; (3) Zeros of $f^{(k)}(z)$ are not the b points of f(z) for each $f{\in}F$ in D. Then F is normal in D. And some examples are provided to show the result is sharp.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제19권3호
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• pp.186-192
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• 2016

Purpose: To evaluate the correlation between colon transit time (CTT) test value and initial maintenance dose of polyethylene glycol (PEG) 4000 or lactulose. Methods: Of 415 children with chronic functional constipation, 190 were enrolled based on exclusion criteria using the CTT test, defecation diary, and clinical chart. The CTT test was performed with prior disimpaction. The laxative dose for maintenance was determined on the basis of the defecation diary and clinical chart. The Shapiro-Wilk test and Pearson's and Spearman's correlations were used for statistical analysis. Results: The overall group median value and interquartile range of the CTT test was 43.8 (31.8) hours. The average PEG 4000 dose for maintenance in the overall group was $0.68{\pm}0.18g/kg/d$; according to age, the dose was $0.73{\pm}0.16g/kg/d$ (<8 years), $0.53{\pm}0.12g/kg/d$ (8 to <12 years), and $0.36{\pm}0.05g/kg/d$ (12 to 15 years). The dose of lactulose was $1.99{\pm}0.43mL/kg/d$ (<8 years) or $1.26{\pm}0.25mL/kg/d$ (8 to <12 years). There was no significant correlation between CTT test value and initial dose of laxative, irrespective of the subgroup (encopresis, abnormal CTT test subtype) for either laxative. Even in the largest group (overall, n=109, younger than 8 years and on PEG 4000), the correlation was weak (Pearson's correlation coefficient [R]=0.268, p=0.005). Within the abnormal transit group, subgroup (n=73, younger than 8 years and on PEG 4000) correlation was weak (R=0.267, p=0.022). Conclusion: CTT test value cannot predict the initial maintenance dose of PEG 4000 or lactulose with linear correlation.