• Journal of Applied Biological Chemistry
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• 제63권1호
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• pp.29-33
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• 2020

한약재의 불법 유통을 방지하기 위해 신속 정확한 원산지 판별방법 개발이 필요함에 따라 TDU-GC/MS를 이용하여 한국품종 당귀와 외국품종 당귀를 판별함과 동시에 한국품종 당귀의 재배지가 한국인지를 판별할 수 있는 기법을 연구하였다. 당귀추출물을 열탈착 시킨 후 냉각응축시스템에서 응축시켜 일시에 GC/MS로 분석한 결과 국산 품종 당귀(참당귀)는 TIC의 RT 26.9-27.2에서 coumarin 유도체인 decursin과 decursinol peak가 확인되었다. 중국 품종 당귀(중당귀)의 경우 RT 17.2 부근에서 ligustilide의 peak가 검출되었다. 국산 품종 참당귀 원산지에 따른 휘발성분의 차이를 알아보기 위하여 twister로 흡착하여 TDU-GC/MS로 m/z 40-400 amu 범위에서 mass spectrum을 측정하였다. 참당귀의 국내 및 중국 재배 시료 TIC는 전반적으로 같은 경향을 냈으나 TIC를 부분 scan한 결과 RT 15.4-16.1에서 국내 및 중국 재배의 peak pattern 차이를 확인할 수 있었다. Peak A (RT 15.54)과 B (RT 16.05)의 비율은 국내 재배는 0.0-0.2, 중국 재배의 경우 0.5-2.8으로서 TDU-GC/MS의 TIC peak pattern 비교를 통한 원산지 판별 가능성을 확인하였다.

• 한국자연치유학회지
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• 제10권2호
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• pp.108-113
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• 2021

배경: 속새 줄기와 뿌리의 추출물에서 항산화 물질의 작용에 관한 결과를 이미 보고하였으나 항산화 성분은 분석되지 않았다. 목적: 속새 줄기와 뿌리 부분의 성분을 추출한 물질들이 항산화 물질의 분자 구조를 확인하는 것이었다. 방법: 성분분석은 열수와 에틸알코올로 추출하여 HPLC와 LC-MS로 분석하였다. 결과: 속새 줄기와 뿌리 추출물의 HPLC 크로마토그램은 파장 205 nm에서 4개의 중요한 peak가 나타났다. 280 nm에 있는 peak 1번은 전형적인 단순 페놀릭형이고, 모두 280 nm와 370 nm 근처에 있는 peak 2~4는 전형적인 플라보노이드 배당체의 형태임을 알 수 있었다. HPLC 분석에 의한 추출물의 항산화도는 740 nm에서 peak의 합은 100% 에탄올 추출물이 3,669 mAU로 제일 높았고, 70% 에탄올 추출물은 3,096 mAU, 열수추출물은 2,868 mAU로 제일 낮았다. 항산화성 추출 물질을 LC-MS 분석한 결과는 peak 3에서는 분자량이 772 da인 kaempferol-3-sophoroside-7-glucoside, peak 4에서는 분자량이 788과 772인 물질 kaempferol-3- sophoroside- 8-glucoside가 확인되었다. 결론: 속새의 항산화 추출물에 항산화 성분이 존재하는 것이 확인되어 속새가 기능성 화장품의 원료로서 가능성이 높아 졌다고 본다.

• 한국수자원학회논문집
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• 제44권1호
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• pp.41-49
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• 2011

본 연구는 한 유역 내에서 단위유량도의 첨두치가 강우 강도에 따라 변동되는 기존 연구 분석 사례를 근간으로 하여 고찰된다. 시간불변이라는 이론적 기본 가정과 달리 호우별 강우강도에 따라 시변(時變)하는 단위유량도를 설정하고 강우사상에 적용하여 유출수문곡선을 산출하여 검토한다. 이 때 적용되는 단위유량도의 경우 첨두유량과 첨두발생시간은 기왕 연구된 강우강도와의 관계식을 검토하여 이용하고 단위유량도 형상은 산출된 첨두치를 적용한 Nash의 단위유량도로 설정된다. 비교 목적을 위해서 적용하는 유역 평균 단위유량도는 강우사상별로 유도된 26개의 단위유량도의 평균 첨두치에 의한 Nash의 모형이다. 호우사상의 강우강도별로 변동되는 단위유량도와 평균단위유량도로부터 산출된 수문곡선의 첨두유량과 첨두발생시간을 관측수문곡선과 비교한다. 비교한 결과 본 연구에서 보완적으로 제시한 시변(時變)의 단위유량도는 평균 단위유량도에 의해서 계산한 첨두홍수량과 첨두발생시간 보다 관측치에 접근함을 보인다.

• Geomechanics and Engineering
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• 제28권3호
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• pp.209-224
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• 2022

In this study, the numerical analysis model of π-beam explosion is established to compare and analyze the failure modes of the π-beam under the action of explosive loads, thus verifying the accuracy of the numerical model. Then, based on the numerical analysis of different protection forms of π beams under explosive loads, the peak pressure of π beam under different protection conditions, the law of structural energy consumption, the damage pattern of the π beam after protection, and the protection efficiency of different protective layers was studied. The testing results indicate that the pressure peak of π beam is relatively small under the combined protection of steel plate and aluminum foam, and the peak value of pressure decays quickly along the beam longitudinal. Besides, as the longitudinal distance increases, the pressure peak attenuates most heavily on the roof's explosion-facing surface. Meanwhile, the combined protective layer has a strong energy consumption capacity, the energy consumed accounts for 90% of the three parts of the π beam (concrete, steel, and protective layer). The damaged area of π beam is relatively small under the combined protection of steel plate and aluminum foam. We also calculate the protection efficiency of π beams under different protection conditions using the maximum spalling area of concrete. The results show that the protective efficiency of the combined protective layer is 45%, demonstrating a relatively good protective ability.

• Journal of Communications and Networks
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• 제11권6호
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• pp.556-563
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• 2009

A side channel analysis is a very efficient attack against small devices such as smart cards and wireless sensor nodes. In this paper, we propose an efficient key detection method using a peak selection algorithm in order to find the advanced encryption standard secret key from electromagnetic signals. The proposed method is applied to a correlation electromagnetic analysis (CEMA) attack against a wireless sensor node. Our approach results in increase in the correlation coefficient in comparison with the general CEMA. The experimental results show that the proposed method can efficiently and reliably uncover the entire 128-bit key with a small number of traces, whereas some extant methods can reveal only partial subkeys by using a large number of traces in the same conditions.

• 한국통신학회논문지
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• 제24권6A호
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• pp.845-854
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• 1999

DS/CDMA 방식의 역방향 링크 구조에 Peak-to-Average Ratio(PAR) 성능은 대역 확산 신호의 위상의 변화로 해석된다. 본 논문에서는 대역확산 신호의 위상 변화를 이용하여 PAR 특성을 해석하는 방법을 제안한다. 이러한 해석 방법을 토대로 기존의 방법을 분석하고, 몇 가지 PAR 성능 개선 방법의 예를 제시하였다. 또한 제시된 방법이 BER 성능에서도 기존의 방법과 큰 차이가 없음을 확인하였다.

• 전력전자학회논문지
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• 제3권4호
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• pp.338-345
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• 1998

The mathematical interpretation of a practical sampler which is useful to obtain the small signal models for the peak and average current mode controls is proposed. Due to the difficulties in applying the Shannons sampling theorem to the analysis of sampling effects embedded in the current mode control, several different approaches have been reported. However, these approaches require the information of the inductor current in a discrete expression, which restricts the application of the reported method only to the peak current mode control. In this paper, the mathematical expressions of sampling effects on a current loop which can directly apply the Shannons sampling theorem are newly proposed, and applied to the modeling of the peak current mode control. By the newly derived models of a practial smapler, the models in a discrete time domain and a continuous time domain are obtained. It is expected that the derived models are useful for the control loop design of power supplies. The effectiveness of the derived models are verified through the simulation and experimental results.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.157-167
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• 2020

The purpose of this study is to analyze the relationship between the occurrence of intermediate peak and time duration, and to conduct a review for the causes of the intermediate peak. In this test, ice impact tests were conducted using a bow side shell frame and ice specimen. A total of 70 samples were manufactured. Two types of ice specimen with relatively different surface conditions were used. The criterion for dividing the two types of ice specimen was the different exposure times to room temperature after freezing. This experiment was conducted for each parameter in order to reproduce the actual icebreaking situation. As a result of the analysis, the intermediate peak in the ice load signal have been found to be caused by mechanisms by which the inner surface of broken ice contact with hull immediately after the initial hitting point of ice has been broken.

• Smart Structures and Systems
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• 제31권1호
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• pp.45-56
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• 2023

Vibration-based structural health monitoring is used to ensure the safety of structures by installing sensors in structures. The peak picking method, one of the applications of vibration-based structural health monitoring, is a method that analyze the dynamic characteristics of a structure using the peaks of the frequency response function. However, the results may vary depending on the person predicting the peak point; further, the method does not predict the exact peak point in the presence of noise. To overcome the limitations of the existing peak picking methods, this study proposes a new method to automate the modal analysis process by utilizing long short-term memory, a type of recurrent neural network. The method proposed in this study uses the time series data of the frequency response function directly as the input of the LSTM network. In addition, the proposed method improved the accuracy by using the phase as well as amplitude information of the frequency response function. Simulation experiments and lab-scale model experiments are performed to verify the performance of the LSTM network developed in this study. The result reported a modal assurance criterion of 0.8107, and it is expected that the dynamic characteristics of a civil structure can be predicted with high accuracy using data without experts.

• 조명전기설비학회논문지
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• 제26권11호
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• pp.75-80
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• 2012

In this paper, the operational characteristics due to the introduction of the superconducting fault current limiter(SFCL) with a peak current limiting function were analyzed in the power distribution system. The parallel structure of the superconducting element can operate the peak current limiting function depending on the transient amplitude of fault current. We studied the operating characteristics of the introduction of the SFCL with a peak current limiting function in the power distribution system. Furthermore, we were analyzed between the SFCL with a peak current limiting function and the protection devices in the power distribution system, through the short circuit experiments.