• 제목/요약/키워드: AAS.

검색결과 657건 처리시간 0.024초

The effect of sweep angle on the limit cycle oscillations of aircraft wings

  • Eken, Seher;Kaya, Metin Orhan
    • Advances in aircraft and spacecraft science
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    • 제2권2호
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    • pp.199-215
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    • 2015
  • This study focuses on the limit cycle oscillations (LCOs) of cantilever swept-back wings containing a cubic nonlinearity in an incompressible flow. The governing aeroelastic equations of two degrees-of-freedom swept wings are derived through applying the strip theory and unsteady aerodynamics. In order to apply strip theory, mode shapes of the cantilever beam are used. The harmonic balance method is used to calculate the frequencies of LCOs. Linear flutter analysis is conducted for several values of sweep angles to obtain the flutter boundaries.

Nonlinear model based particle swarm optimization of PID shimmy damping control

  • Alaimo, Andrea;Milazzo, Alberto;Orlando, Calogero
    • Advances in aircraft and spacecraft science
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    • 제3권2호
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    • pp.211-224
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    • 2016
  • The present study aims to investigate the shimmy stability behavior of a single wheeled nose landing gear system. The system is supposed to be equipped with an electromechanical actuator capable to control the shimmy vibrations. A Proportional-Integrative-Derivative (PID) controller, tuned by using the Particle Swarm Optimization (PSO) procedure, is here proposed to actively damp the shimmy vibration. Time-history results for some test cases are reported and commented. Stochastic analysis is last presented to assess the robustness of the control system.

Aircraft and spacecraft structural analysis with hybrid criterion of smart control

  • C.C., Hung;T., Nguyen
    • Advances in aircraft and spacecraft science
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    • 제9권6호
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    • pp.553-569
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    • 2022
  • In this article, we propose a criterion for ensuring the asymptotic stability of large multiple delays, based on the direct Lyapunov method. Based on this criterion and distributed control scheme, the controllers are synthesized by the PDC to stabilize these large-scale systems with multiple delays. And we focus on the results which shows the high effective by the proposed theory utilized for damage propagation for aircraft structural analysis of composite materials. Finally, the numerical simulations confirmed the effectiveness of the method.

Heat and mass transfer processes at the most heat-stressed areas of the surface of the descent module

  • Oleg A., Pashkov;Boris A., Garibyan
    • Advances in aircraft and spacecraft science
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    • 제9권6호
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    • pp.493-506
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    • 2022
  • The study presents the results of the research of heat and heat exchange processes on the heat-stressed elements of the structure of an advanced TsAGI descent vehicle. The studies were carried out using a mathematical model based on solving discrete analogs of continuum mechanics equations. Conclusions were drawn about the correctness of the model and the dependence of the intensity of heat and mass transfer processes on the most heat-stressed sections of the apparatus surface on its geometry and the catalytic activity of the surface.

Si기판 세정조건에 따른 산화막의 특성연구 (A Study on characteristics of thin oxides depending on Si wafer cleaning conditions)

  • 전형탁;강응렬;조윤성
    • 한국재료학회지
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    • 제4권8호
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    • pp.921-926
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    • 1994
  • Gate oxide의 특성은 세정공정에서 사용된 last세정용액에 큰 영향을 받는다. Standard RCA, HF-last, SCI-last, and HF-only 공정들은 gate oxidation하기 전 본 실험에서 행해진 세정공정들이다. 세정공정을 마친 Si기판들은 oxidation furnace에서 $900^{\circ}C$로 thermal oxidation공정을 거치게 된다. 100$\AA$의 gate oxide를 성장시킨 후 lifetime detector, VPD, AAS, SIMS, TEM, 그리고 AFM고 같은 분석장비를 이용하여 oxide의 특성을 평가했다. HF-last와 HF-only 공정에 의해 금속 불순물들이 매우 효과적으로 제거됐음을 알 수 있었다. Oxide의 표면 및 계면 형상은AFM과 TEM 측정을 통하여 관찰하였다. 표면거칠기는 SCI 세정용액을 사용한 splits 실험에서 불균일함이 관찰되었고 HF-only세정공정을 거친 시편 및 계면이 가장 smooth했다.

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불꽃 및 비불꽃원자흡수분광법을 이용한 뇨중 카드뮴 분석 (Analysis of Cadmium in Urine using Flame and Flameless Atomic Absorption Spectrophotometry)

  • 함용규;이석기;전해홍;정창웅;손부순
    • 분석과학
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    • 제12권5호
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    • pp.355-359
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    • 1999
  • 뇨중 미량 카드뮴 분석에 흑연로 장치가 부착된 원자흡수분광광도계(GFAAS)를 사용하였다. 불꽃분광법에서 시료는 회화하여 Na-DDTC로 착물을 형성한 후 MIBK로 추출하였으며, 비불꽃분광법에서는 1% Triton X-100과 1% $HNO_3$으로 5배 희석시킨 후 $Pd(NO_3)_2$를 매트릭스 개선제로 농도를 변화시키면서 회화 온도 $450-750^{\circ}C$에서 pyrocoated 흑연 튜브를 사용하여 분석하였다. 그 결과 불꽃분광법보다는 비불꽃분광법이 전처리가 간단하고 재현성있게 나타났으며, 비불꽃분광법을 이용한 경우 $Pd(NO_3)_2$ 100 mg/L을 사용하여 회화온도 $550^{\circ}C$에서 분석시 가장 높은 흡광도를 나타냈다. 본 분석법을 표준뇨인 Lononorm-Metalle 3 중의 카드뮴 분석에 적용하였다.

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Saccharomyces cerevisiae을 이용한 사람의 H-, L-ferritins 발현 연구 (Expression of Human Heavy-Chain and Light-Chain Ferritins in Saccharomyces cerevisiae for Functional Foods and Feeds)

  • 한혜송;이중림;박시홍;김재환;김해영
    • 한국미생물·생명공학회지
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    • 제36권3호
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    • pp.221-226
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    • 2008
  • 효모에서 사람의 H-, L-ferritin을 생산하기 위해서, 기존에 복제된 vector를 사용하였으며,단백질을 발현하기 위해서 각각의 증폭된 ferritin 유전자를 GALI promoter에 의해 조절되는 pYES2.1/V5-His-TOPO 효모 발현 vector에 삽입하였다. Western blot 분석을 통해서 사람의 H-, L-ferritin subunits을 함유한 재조합 효모에서 사람의 ferritin이 발현된 것을 확인할 수 있었다. 또한 Atomic absorption spectrometry(AAS) 분석을 통해서 형질변환된 효모의 철 함유량이 대조군과 비교하여 $1.6{\sim}l.8$배 증가한 것을 확인하였다. 향후 ferritin이 함유된 형질변환 효모를 사용하여 잠재적으로 철이 강화된 영양성분을 기능성 식품과 사료에 이용할 수 있을 것이다.

2D:4D 비율과 MMPI-2의 상관관계 연구 (Correlation between 2D:4D Ratio and Minnesota Multiphasic Personality Inventory-2 Questionnaire)

  • 권오현;이재혁
    • 동의신경정신과학회지
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    • 제29권2호
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    • pp.69-77
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    • 2018
  • Objectives: To determine the relationship between 2D:4D ratio and Minnesota Multiphasic Personality Inventory-2 Questionnaire (MMPI-2 scales). Methods: The 2D:4D ratio in 101 Korean medical students was measured. MMPI-2 test was performed. Results: In the unisex group, there were significantly positive correlations between the 2D:4D ratio and MMPI-2 scales of Hs, D, Pt, Sc, Si, RC1, RC2, RC8, INTR, ANX, OBS, HEA, BIZ, LSE, WRK, TRT, A, R, Mt, PK, and AAS while there were significantly negative correlations between the 2D:4D ratio and MMPI-2 scales of Es and Do. In the male group, there were significantly positive correlations between the 2D:4D ratio and MMPI-2 scales of Hs, RC1, RC8, HEA, and AAS while there were significantly negative correlations between the 2D:4D ratio and MMPI-2 scale of AGGR. In the female group, the 2D:4D ratio showed significantly positive correlations with MMPI-2 scales of Pt, Sc, Si, RC1, RC2, RC6, INTR, DEP, BIZ, LSE, WRK, A, Mt, PK, and Ho while it showed significantly negative correlations with MMPI-2 scale of Do. Conclusions: MMPI-2 scales are correlated with the 2D: 4D ratio. Therefore, 2D: 4D ratio could be used as an indicator to reflect multiphasic personality of individuals.

우리나라 일부 우유의 무기질 함량 조성에 관한 연구 (Composition of Mineral Contents in Korean Cow무s Milk)

  • 이영희;정문호
    • 한국환경보건학회지
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    • 제30권1호
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    • pp.29-40
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    • 2004
  • This study was performed to investigate and assess the composition of mineral and macronutrient contents in Korean cow′s milk.48 individual farm raw milk, 10 plant raw milk and 29 market milk were collected from June to August in 2003. The minerals such as calcium(Ca), potassium(K), magnesium(Mg), sodium(Na), zinc(Zn), iron(Fe) and phosphorus(P) were determined by using atomic absorption spectrometer(AAS). The macronutrients such as fat, protein and lactose were tested by using IR spectrometer. The obtained analytical results of minerals(mg/100 g) and rnaetronutrients (%) are as follows:1. In case of raw cow′s milk ; Ca 113.56, K 144.09, Mg 10.86, Na 42.53, Zn 0.42, Fe 0.030, p 113.32, fat 3.85, protein 3.08, lactose 4.80,2. In case of market cow′s milk ; Ca 103.04, K 142.46, Mg 10.27, Na 43.21, Zn 0.40, Fe 0.034. p 97.30, fat 3.78, protein 3.05, lactose 4.70,3. In case of fortified market cow′s milk ; Ca 165.40, K 145.79, Mg 10.57. Na 42.55, Zn 0.57, Fe 0.414, p 94.68, fat 3.74, protein 3.08, lactose 4.68,4. In case of processed market cow′s milk ; Ca 134.72, K 142.74, Mg 10.33, Na 45.07, Zn 0.50, Fe 0.650, p 92.48, fat 3.72, protein 3.07, lactose 4.74. According to the group of market milk(milk, fortified market row′s milk, processed market cow′s milk), the mean concentration of Ca and Fe were significantly higher in fortified and processed milk than milk(p<0.05). There were no significant differences in macronutrient(fat, protein, lactose) and mineral contents between pasteurized milk and UHT(ultra high temperature) treated milk($\alpha$=0.05). The labeled "Nutritional Facts" of market milk were satisfied with "Labeling Standards for Livestock Products of Korea". The measured mean concentrations of Ca, Fe, Zn were generally higher than lower limit of labeled value(above 80% of labeled value). The mean concentration of sodium was lower than upper limit of labeled value(below 120% of labeled value).