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Characteristics of woodland changes in an agricultural landscape
이영창(Young-chang Lee),정운주(Woon-joo Jung),김근호(Keun-Ho Kim) 충남대학교 농업과학연구소 2011 농업과학연구 Vol.38 No.3
Recent landscape changes from human activities, such as agricultural development and urbanisation frequently result in the loss of habitats, the reduction in habitat patch size and an increasing isolation of habitat patches. However, there is little information on woodland changes in agricultural landscapes. Therefore, the aim of this research was to assess spatial characteristics and changes of woodland in an agricultural landscape and how these may have had an impact on ecological process for 33 years. One of the agricultural landscape character units was analysed based on aerial photographs from 1976, 1983, 1994, 2002 and 2009 in Gwangju city. The results indicated that landscape ecological metrics clearly showed that they could be used to monitor changes of woodland ecological conditions during the past 33 years. The results imply that particularly human activities have been leading to the decrease of the mean size of woodland patches and finally result in woodland isolation. These changes may have a negative impact on woodland bird species in the study area. This woodland information can be used to identify the potential and specific needs for setting priorities for conservation planning.
Characteristics of woodland changes in an agricultural landscape - The case of Gwangju
이영창,정운주,김근호,Lee, Young-Chang,Jung, Woon-Joo,Kim, Keun-Ho Institute of Agricultural Science 2011 Korean Journal of Agricultural Science Vol.38 No.3
Recent landscape changes from human activities, such as agricultural development and urbanisation frequently result in the loss of habitats, the reduction in habitat patch size and an increasing isolation of habitat patches. However, there is little information on woodland changes in agricultural landscapes. Therefore, the aim of this research was to assess spatial characteristics and changes of woodland in an agricultural landscape and how these may have had an impact on ecological process for 33 years. One of the agricultural landscape character units was analysed based on aerial photographs from 1976, 1983, 1994, 2002 and 2009 in Gwangju city. The results indicated that landscape ecological metrics clearly showed that they could be used to monitor changes of woodland ecological conditions during the past 33 years. The results imply that particularly human activities have been leading to the decrease of the mean size of woodland patches and finally result in woodland isolation. These changes may have a negative impact on woodland bird species in the study area. This woodland information can be used to identify the potential and specific needs for setting priorities for conservation planning.
鄭英暢(Young Chang Jung) 호서대학교 사회과학연구소 1985 社會科學硏究 Vol.4 No.1
Being that the melting point of silicon is 1800 J/gr, in this paper it is interested that Si-Semiconductors will be worth using of Peltier effect. For attachment of semiconductor chips, a cure schedule of 2 hours at 200°C has been found to yield a stable and reliable. In the results, it is a semi-permant element and using with a heating element the temperature is up to 200°C over. At the end, it will be possible to improve an excellent elements with a way.
정영창(Jung, Young-Chang),김동진(Kim, Dong-Jin),김정도(Kim, Jeong-Do),정우석(Jung, Woo-Suk) 한국산학기술학회 2005 한국산학기술학회논문지 Vol.6 No.2
본 논문은 이온 선택성 전극을 모듈화한 MACS를 사용하여 시스템의 크기를 축소할 수 있었고, PDA를 사용함으로써 측정된 데이터를 장소에 구애받지 않고 분석할 수 있는 휴대용 전자혀 시스템을 개발하였다. MACS는 NH₄⁺, Na⁺, CI⁻, N03⁻, K⁺, Ca2⁺, Na⁺, pH의 7종의 이온 선택성 전극을 이용하여 구성하였으며, 초기화 및 교정과정과 완충용액에 의한 안정화 과정을 거친 후 MACS로 시료에 대한 각각의 이온선택성 전극의 변화를 측정한다. 이렇게 각 전극으로부터 측정된 데이터를 이용하여 신경회로망 알고리즘으로 측정된 시료의 종류를 구분할 수 있다. 실험은 분류가 어렵다고 알려진 고급양주와 저급양주를 분류하는 것으로 진행되었으며, 성공적이며 우수한 설험 결과를 얻었다. 이로부터 사용된 알고리즘이 휴대용 전자혀 시스템에 적절히 사용될 수 있음을 밝혔으며, 설제 휴대용 전자혀 시스템에 간단한 학습에 의해 적용될 수 있을 것으로 생각된다. In this paper, we have designed and implemented a portable e-tongue (electronic tongue) system using MACS (multi array chemical sensor) and PDA. The system embedded in PDA has merits such as comfortable user interface and data transfer by internet from on-site to remote computer. MACS was made up 7 electrodes (NH₄⁺, Na⁺, Cl⁻, N03-, K⁺, Ca2⁺, Na⁺ pH) and a reference electrode. For learning the system, we adapted the Levenberg-Marquardt algorithm based on the back-propagation, which could iteratively learned the pre-determined standard patterns, in etongue system. Conclusionally, the relationship between the standard patterns and unknown pattern can be easily analyzed. The e-tongue was applied to whiskeys and cognac (one high level whisky, one low level whiskey, two cognac) and 2 sample whiskeys for each standard patterns and unknown patterns. The relationship between the standard patterns and unknown patterns can be easily analyzed.
비정질 $Al_2O_3$ 코아 재료를 이용한 Solenoid 형태의 고품질 RF chip 인덕터에 관한 연구
이재욱,정영창,윤의중,홍철호,Lee, Jae-Wook,Jung, Young-Chang,Yun, Eui-Jung,Hong, Chol-Ho 대한전자공학회 2000 電子工學會論文誌-SD (Semiconductor and devices) Vol.37 No.6
우수한 성능을 가지며 소형${\cdot}$경량인 무선통신기기를 구현하기 위해서는 GHz 대의 고주파수에서 동작하는 소형 RF chip 인덕터의 개발은 중요한 연구분야가 되어왔다. 또한 최근 많이 사용되는 자성 ferrite core 재료는 300MHz 이상의 주파수영역에서 자화율이 급속하게 감소하여 고성능 RF chip 인덕터 개발에 큰 장애가 되고 있다. 따라서 본 논문에서는 비정질 $Al_2O_3$ 코아 재료를 응용한 단순 solenoid 형태의 소형${\cdot}$고성능 RF chip 인덕터를 연구하였다. Cu를 코일 (직경=40${\mu}m$)로 사용하였고 인덕터 크기는 $2.1mm{\times}1.5mm{\times}1.0mm$였다. 외부 전류원은 코일의 양단을 코아 가장자리에 적층된 Au 막에 본딩시킨 후 인가되었다. 코아의 성분은 EDX를 사용하여 분석하였다 개발된 인덕터의 인덕턴스 (L), quality factor (Q), 인피던스(Z)등의 주파수 특성은 RF impedance/Material Analyzer (HP16193A test fixture가 장착된 HP4291B)로 측정되었다. 인덕터들의 인덕턴스 값은 22 nH ~ 150 nH 범위를 가지며, 이들의 자기공진주파수 (SRF)는 1~3.5GHz 영역을 나타낸다. 또한 자기공진주파수가 증가함에 따라 인덕턴스 값이 감소하는 경향을 보이고 있다. 임피던스는 공진주파수에서 최대 값을 가지며 Q-factor의 값은 500 MHz ~ 1.5 GHz 주파수 범위에서 최대 70~97까지 얻어졌다. Recently, there is a growing need to develope small-size RF chip inductors operating to GHz to realize high-performance, micro-fabricated wireless communication products. For the development of high-performance RF chip inductors, however, the ferrite-based chip inductors can not be used above 300MHz due to the limitation of the permeability of this material. In this work, small-size, high-performance RF chip inductors utilizing amorphous $Al_2O_3$ core material were investigated. Copper (Cu) with 40${\mu}m$ diameter was used as the coils and the chip inductor size fabricated in this work is $2.1mm{\times}1.5mm{\times}1.0mm$. The external current source was applied after bonding Cu coil leads to gold pads electro-plated on the bottom edges of a core material. The composition of core materials was measured using a EDX. High frequency characteristics of the inductance (L), quality factor (Q), and impedance (Z) of developed inductors were measured using an RF Impedance/Material Analyzer (HP4291B with HP16193A test fixture). The developed inductors have the self-resonant frequency (SRF) of 1 to 3.5 GHz and exhibit L of 22 to 150 nH. The L of the inductors decreases with increasing the SRF. The Z of the inductors has the maximum value at the SRF and the inductors have the quality factor of 70 to 97 in the frequency range of 500 MHz to 1.5 GHz.