• Journal of electromagnetic engineering and science
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• 제7권3호
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• pp.103-108
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• 2007

In this paper, a low-power 2.4 GHz front-end for sensor network application (IEEE 802.15.4 LR-WPAN) is designed in a 0.18 um CMOS process. A power supply circuit with a novel temperature-compensation scheme is presented. The simulation and measurement results show that the front-end (LNA, Mixer) can achieve a voltage gain of 35.3 dB and a noise figure(NF) of 3.1 dB while consuming 5.04 mW (LNA: 2.16 mW, Mixer: 2.88 mW) of power at $27^{\circ}C$. The NF includes the loss of BALUN and BPF. The low-IF architecture is used. The voltage gain, noise figure and third-order intercept point (IIP3) variations over -45$^{\circ}C$ to 85$^{\circ}C$ are less than 0.2 dB, 0.25 dB and 1.5 dB, respectively.

• 한국식품영양학회지
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• 제14권5호
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• pp.418-422
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• 2001

시판되는 4개 사 고춧가루를 구입하여 고춧가루의 품질에 관한 이화학적 특성을 비교 분석하였다. 고춧가루 선호도를 결정하는 것은 색상인데 C사 제품의 L값이 46.667로 가장 높았으며 a, b값도 22.738과 19.941로 제일 높게 나왔다. 고추의 적색소인 capsanthin은 D사가 80.0mg/100g으로 가장 많았으며 A, C, B사가 각각 75.0, 58.9, 51.0mg/100g 순이었고 ASTA color 도 같은 경 향을 보였다. Capsanthin 양과는 달리 L, a, b값 모두 C사가 제일 높게 나왔는데 이는 고춧가루의 입도에 의한 영향 때문으로 여겨진다 각 고춧가루의 pH 차이는 크지 않았으며 유기산은 A, B, D사 제품에서 quinic acid가 가장 많이 검출되었으며 C사 제품은citric acid가 가장 높게 검출되었다. 신미성분 가운데 capsaicin은 D사가 59.93mg/100g으로 가장 많았으며 B사가 25.87mg/100g으로 제일 적었으며 capsaicinoids는 각각 62.93, 28.20mg/100g로 나타나 2배 이상의 차이를 보였다. 미생물의 발생 가능성을 추정할 수 있는 수분활성 도는 A, B, C, D사가 각각 0.584, 0.676, 0.526 및 0.568 로 나타나 A, C, D사 제품은 문제가 없을 것으로 예측되나 B사 제품의 수분활성도가 0.676으로 곰팡이 발생 우려가 있을 것으로 예측되었다.

• 한국초전도ㆍ저온공학회논문지
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• 제23권3호
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• pp.45-50
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• 2021

In this study, the effect of the size of B powder on the critical current density (J_c) of MgB₂ prepared by an in situ reaction process was investigated. Various combinations of B powders were made using a micron B, ball-milled B and nano B powders. Micron B powder was reduced by ball milling and the milled B powder was mixed with the micron B or nano B powder. The mixing ratios of the milled B and micron or nano B were 100:0, 50:50 and 0:100. Non-milled micron B powder was also mixed with nano powder in the same ratios. Pellets of (2B+Mg) prepared with various B mixing ratios were heat-treated to form MgB₂. T_c of MgB₂ decreased slightly when the milled B was used, whereas the J_c of MgB₂ increased with increasing amount of the milled B or the nano powder. The used of the milled B and nano B power promoted the formation MgB₂ during heat treatment. In addition to the enhanced formation of MgB₂, the use of the powders reduced the grain size of MgB₂. The use of the milled and nano B powder increased the J_c of MgB₂. The highest J_c was achieved when 100% nano B powder was used. The J_c enhancement is attributed to the high volume fraction of the superconducting phase (MgB₂) and the large grain boundaries, which induces the flux pinning at the magnetic fields.

• 수산해양기술연구
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• 제16권2호
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• pp.69-76
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• 1980

This paper describes the measurement of the underwater noises produced by the engine vibration around the engine room of stern trawler MIS Sae-Ba-Da(2275GT, 3,600 PS) and pole kner M/S Kwan-Ak-San (243 GT, 1000 PS) while the ship is stopping. The underwater noise pressure level was measured with the underwater level meter of which measuring range is 100 to 200 dB(re bLPa). A and B denotes the maximum pressure level measured at right beneath the bottom of the engine room, while the main engine of the Sae-Ba-Da revoluted at 750 and 500 rpm, respectively. C denotes that of the main engine of the Kwan-Ak-San revoluted at 350 rpm, and D that of the generator of the Sae-Ba-Da revoluted at 720 rpm. Thus A, B, C and D were set for the standard sound source for the experiment. The results obtained are as follows: 1. The noise Pressure level at A, B, C and D were 170.5,165,153 and 158dB, respectively. 2. When the check points distanted vertically 1, 10, 20, 30, 40, 50m from the sound source, the underwater noise presure levels were 170.5, 155, 148, 144 and 138 dB and the directional angle was 116\ulcorner in case of A. 3. The sound level attenuated at the rate of 20dB per 10" meters of the horizontal distance from the sound sources. 4. The frequency distribution of the noise was 100Hz to 10KHz and predominant frequency was 700 to 800Hzminant frequency was 700 to 800Hz

• ETRI Journal
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• 제42권5호
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• pp.781-789
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• 2020

In this study, an E-band low-noise amplifier (LNA) monolithic microwave integrated circuit (MMIC) has been designed using silicon-germanium 130-nm bipolar complementary metal-oxide-semiconductor technology to suppress unwanted signal gain outside operating frequencies and improve the signal gain and noise figures at operating frequencies. The proposed impedance-controllable filter has series (R_s) and parallel (R_p) resistors instead of a conventional inductor-capacitor (L-C) filter without any resistor in an interstage matching circuit. Using the impedance-controllable filter instead of the conventional L-C filter, the unwanted high signal gains of the designed E-band LNA at frequencies of 54 GHz to 57 GHz are suppressed by 8 dB to 12 dB from 24 dB to 26 dB to 12 dB to 18 dB. The small-signal gain S₂₁ at the operating frequencies of 70 GHz to 95 GHz are only decreased by 1.4 dB to 2.4 dB from 21.6 dB to 25.4 dB to 19.2 dB to 24.0 dB. The fabricated E-band LNA MMIC with the proposed filter has a measured S₂₁ of 16 dB to 21 dB, input matching (S₁₁) of -14 dB to -5 dB, and output matching (S₂₂) of -19 dB to -4 dB at E-band operating frequencies of 70 GHz to 95 GHz.

• 호남수학학술지
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• 제10권1호
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• pp.23-30
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• 1988

Let C[C, D] and $S^{*}[C,\;D]$ denote the classes of functions g, g(0)=1-g'(0)0=0, analytic in the unit disc E such that $\frac{(zg{\prime}(z)){\prime}}{g{\prime}(z)}$ and $\frac{zg{\prime}(z)}{g(z)}$ are subordinate to $\frac{1+Cz}{1+Dz{\prime}}$ $z{\in}E$, respectively. In this paper, the classes K[A,B;C,D] and $C^{*}[A,B;C,D]$, $-1{\leq}B<A{\leq}1$; $-1{\leq}D<C{\leq}1$, are defined. The functions in these classes are close-to-convex. Using the properties of convolution operators, we deal with some problems for our classes.

• 한국식품조리과학회지
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• 제7권4호
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• pp.71-86
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• 1991

This study was attempted to enhance nutritional value of cooked rice by adding milk in cooking water. Cooked and soaked rice with five different levels of milk in cooking water (0%, A: 30%, B: 50%, C: 70%, D: 100%, E) was tested for rheological parameters, fine structural changes, sensory evaluation. 1. Water absorbance of raw rice in cooking water with varying amountes of milk, was tested at $5^{\circ}C$ and $15^{\circ}C$ for 2 hours. Water absorption ratio was decreased as milk content was increased and soaking temperature was low. Time for maximum water absorption of sample A was 40 min at 1$15^{\circ}C$ but for sample B to D, it was not reached until 120 min. 2. Electronmicroscopic observation revealed that starch granules of rice lost their regular forms by soaking for 90 minutes, but recovered most of initial regularity after 24 hours. Increase in milk content of soaking water decreased marginal sharpness of the starch granule, presumably due to reduced swelling of the granule. 3. Degree of gelatinization of cooked rice was highest in sample A and progressively decreased as milk content was increased. It was, however, increased in all samples when the cooking water to rice ratio was raised from 160% to 180%. During 4 hour storage, rates of retrogradation were not different between A and B samples, but those of C, D and E were about 2.5 times higher than A and B under the optimal condition of 170% cooking water to rice ratio. This was in the order reverse to hardness order of AC>A, D＞E at cooking water to rice ratios of 160% and 170%, above which A sample surpassed the rest of samples. 4. Sensory evaluation conducted by fifteen university students as panelists showed that there were more significant differences among five samples in flavour, texture than appearance and a notable preference for b and C over A, D and E.

• 대한치과보철학회지
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• 제34권2호
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• pp.320-334
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• 1996

Dental cast and die materials are essential material using in almost dental prsthodontic procedure and it's most important requirement is accuracy for reqorducing the oral anatomical structures. In this study, 5 abutments A, B, C, D, E were fabricated on the metal master model to simulate the arch form and specimens were poured with 4 cast materials. Inter-abutment distances, A-B, A-C, A-D, A-E, B-C, B-D were calculated using the photo-scanning and the deviations from the metal master model were also evaluated. The results were as follows; 1. The distance between A-B, A-C, A-D, A-E, B-C, B-D of the abutments A, B, C, D, E of each cast material was calculated. And after comparing the deviations between the metal master model. $Fujirock^{(R)}$ showed the lowest value with $0.20{\pm}0.22mm$, and the deviation increased in the order of $Suprastone^{(R)}$, Epoxy $Die^{(R)}$, Die $Keen^{(R)}$. There was significant difference between $Fujirock^{(R)}$ and Epoxy $Die^{(R)}$, Die $Keen^{(R)}$. 2. In each calculation area, the difference in measurements between cast material and metal master model showed singificant difference between A-B and Cross arch measure-ments of A-D, B-D, A-E(p<0.05). 3. The difference in measurements between cast material and metal master model in the A-B area showed $Fujirock^{(R)}$ to be the lowest with $0.05{\pm}0.04$mm and increased in the order of Die $Keen^{(R)}$, $Suprastone^{(R)}$, Epoxy $Dies^{(R)}$. There was significant difference between $Fujirock^{(R)}$ and $Suprastone^{(R)}$, Epoxy $Die^{(R)}$ (p<0.05). 4. The difference in measurements between cast material and metal master model in the B-C area showed $Fujirock^{(R)}$ to bo the lowest with $0.17{\pm}0.11$mm and increased in the order of $Suprastone^{(R)}$, Die $Keen^{(R)}$, Epoxy $Dies^{(R)}$. There was significant difference between $Fujirock^{(R)}$ and Die $Keen^{(R)}$, Epoxy $Die^{(R)}$(p<0.05). 5. The difference in measurements between cast material and metal master model in the B-D area showed $Fujirock^{(R)}$ to bo the lowest with $0.13{\pm}0.07$mm, Epoxy $Dies^{(R)}$and increased in the order of $Suprastone^{(R)}$, Die $Keen^{(R)}$. There was significant difference between $Fuji-rock^{(R)}$ and Die Keen(p<0.05). 6. In this experiment, Epoxy $Dies^{(R)}$ showed mean contraction in every calculation area. And when reconstruction cross arch restorations it is thought that distortion should be considered in every cast material.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제30권3호
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• pp.337-345
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• 2023

Different versions of the boundary Schwarz lemma for the 𝒩 (𝜌) class are discussed in this study. Also, for the function g(z) = z+b₂z²+b₃z³+... defined in the unit disc D such that g ∈ 𝒩 (𝜌), we estimate a modulus of the angular derivative of g(z) function at the boundary point 1 ∈ 𝜕D with g'(1) = 1 + 𝜎 (1 - 𝜌), where ${\rho}={\frac{1}{n}}{\sum\limits_{i=1}^{n}}g(c_i)={\frac{g^{\prime}(c_1)+g^{\prime}(c_2)+{\ldots}+g^{\prime}(c_n)}{n}}{\in}g^{\prime}(D)$ and 𝜌≠1, 𝜎 > 1 and c₁, c₂, ..., c_n ∈ 𝜕D. That is, we shall give an estimate below |g"(1)| according to the first nonzero Taylor coefficient of about two zeros, namely z = 0 and z ≠ 0. Estimating is made by using the arithmetic average of n different derivatives g'(c₁), g'(c₂), ..., g'(c_n).

• Applied Biological Chemistry
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• 제46권3호
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• pp.246-250
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• 2003

양하(Zingiber mioga Roscoe) 근경의 에탄을 추출물을 재료로 Staphylococcus aureus, Bacillus subtilis 및 B. cereus에 대한 activity-guided fractionation을 실시하여 항균성 물질 세가지준 얻었다. 항균력실험 결과, 화합물 I과 111은 세가지균주 모두에 활성이 있었고, 화합물 II에서는 B. subtilis과 B. cereus에서만 활성이 나타났다. 그 중에서 가장 활성이 강한 화합물 I을 Bioscreen C로 optical density(600 nm)를 측정하여 증식억제실험을 한 결과 10 ppm 처리시 B. subtilis과 B. cereus에서 72시간동안 강한 증식억제효과를 나타내었으며, S. aureus에서는 25 ppm 처리시 72시간동안 완전증식억제효과를 나타내었다. $1^H-NMR$, ${13}^C-NMR$, DEPT,$1^H-1^H$ COSY, HMQC, HMBC 및 IR 스펙트럼 등을 분석한 결과 화합물 I, II, III은 labdane-type diterpene인 $(E)-8{\beta}(17)-epoxylabd-12-ene-15,16-dial(C_{20}H_{30}O_3,\;MW=318)$, $galanolactone(C_{20}H_{30}O_3,\;MW=318)$ 그리고 galanal A($C_{20}H_{30}O_3,\;MW=318$)로 각각 동정되었으며, 이들은 양하의 근경에서는 처음 분리된 것이다.