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Decomposition Models of the Organic Matters in Cultural Media and the Litters in Forest (배양액에서의 유기물분해와 식물군락에서의 낙엽분해에 관한 모델)

  • 이웅상;장남기
    • Asian Journal of Turfgrass Science
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    • v.9 no.2
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    • pp.119-129
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    • 1995
  • Decomposition rates of glucose, starch, spinach leaves and litters in forests are calculated by equation dC dt=-kC(Co-1nC), dC- dt=$-kC^2$, and Olson's negative exponential decay model.dC dt = - kC =-kC(Co - InC) showed a very close fit to decomposition of the organic matters in cultural media by purified microorganisms and dC dt=$-kC^2$ to decomposition of the litters in forests. Key words: Organic matters, Cultural media, Glucose, Starch, Leaves, Litters.

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Hot Issue-IT-SoC Fair & IT-SoC 융합 컨퍼런스 2007

  • IT-SoC Association
    • IT SoC Magazine
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    • s.21
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    • pp.24-35
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    • 2007
  • 국내 유일 SoC/IP 전문 전시회인 IT-SoC Fair가 오는 25일 7회째 막을 올린다. 쉽지 않은 대내외 환경 속에서도 꾸준한 발전을 이루고 있는 국내 SoC기업들이 올린 알찬 성과를 돌아보고 국내외 기술 및 산업 전망을 통해 보다 큰 내년을 준비하는 자리다. 특히 올해는 IT-SoC 융합 컨퍼런스, LG DAY, 비즈니스 상담회 등 다양한 부대 행사를 마련해 IT-SoC Fair 2007이 참가기업 모두에게 실질적인 비즈니스의 장이 될 수 있도록 기획했다.

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FCXO ; A Fuzzy Compensated Crystal Oscillator

  • de los Mozos, Mario Reyesr;Valderrama, Elena;Arguelles, Javier
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1993.06a
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    • pp.842-844
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    • 1993
  • We present a F.L.C. (Fuzzy Logic Controller) to control of the oscillation frequency of a V.C.X.O. (Voltage Controled Crystal Oscillator). This F.C.X.O. maintains stable its oscillation frequency inside a range of 1 ppm (one part per millon), with temperature between -55$^{\circ}C$ to+75$^{\circ}C$.

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The Effect of Temperature on the Colony Development of Bombus ignitus Smith (호박벌(Bombus ignitus Smith)의 봉군발육에 미치는 영향)

  • 이상범;마영일;배태웅
    • Journal of Life Science
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    • v.9 no.4
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    • pp.395-407
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    • 1999
  • The queens of Korean native bumblebee species, Bombus ignitus were collected from the field in the spring of 1997 and reared under the various temperatures as 15$^{\circ}C$$\pm$1$^{\circ}C$, 2$0^{\circ}C$$\pm$1$^{\circ}C$, $25^{\circ}C$ $\pm$1$^{\circ}C$, 3$0^{\circ}C$$\pm$1$^{\circ}C$, 60%$\pm$5% of relative humidity and 14L : 10D, to investigate their ecological characteristics, as comparing with control(29$^{\circ}C$$\pm$1$^{\circ}C$, 60%$\pm$5% of relative humidity and red light). As a result, eggs were laid by foundation queen at 15$^{\circ}C$, but they didn't hatched out while at 2$0^{\circ}C$ eggs were laid by them and they hatched out. When a foundation queen laid eggs at $25^{\circ}C$ and they all were hatched out and normally grown. Finally they were developed to the normal colony. B. ignitus worker survived for 77days at 2$0^{\circ}C$, about 69days at $25^{\circ}C$, about 68days at 3$0^{\circ}C$ and about 63days at 29$^{\circ}C$(control). The first brood workers emerged in 25-27days from the egg which a foundation queen laid. At the various temperatures, the captive queens stand to lay eggs in about 18days at 15$^{\circ}C$, 15days at 2$0^{\circ}C$, 11days at $25^{\circ}C$, 11days at 3$0^{\circ}C$ and 4days in control. The first worker and the first drone from the egg cell of the collected queens appeared in about 27days and 72days at 2$0^{\circ}C$, 26days and 88days in $25^{\circ}C$, 24days and 65days at 3$0^{\circ}C$, 25days and 71days in control, respectively. In colony foundation, 33% of the collected queen at 2$0^{\circ}C$ and $25^{\circ}C$, 100% of the disposed queen at 3$0^{\circ}C$ and in control, and 67% of them at 3$0^{\circ}C$ and in control both produced new queens in 66days and 88days, respectively. The life span of the colony founded covered fro about 3 months at $25^{\circ}C$, 3$0^{\circ}C$ and in control. At lower temperatures, the life span of queen is shorter; 2 months at 15$^{\circ}C$ and 3 months at 2$0^{\circ}C$, respectively. A colony which normally developed, varied in size with rearing temperatures; about 20heads at 2$0^{\circ}C$, 482heads at $25^{\circ}C$, 330heads at 3$0^{\circ}C$ and 452heads in control. A foundation queen monthly oviposited 1.5egg cells at 15$^{\circ}C$, 3.0egg cells at 2 $0^{\circ}C$, 21.7egg cells at $25^{\circ}C$, 42.3egg cells at 3$0^{\circ}C$ and 47.0egg cells in control. As a colony developed in June and July, egg cells as well as daily average cells increased in number, as compared to those in May and August. Also, in June and July, interval(days) of egg laying is shorter than in May and August. Number of nectar pots during the colony development varied with rearing temperatures; 31pots at $25^{\circ}C$, 39pots at 3$0^{\circ}C$, 23pots in control. The emergence of new queen showed a distinctively different two patterns; early emerging type and late emerging type. Workers are rapidly increased from early in July to early in August at $25^{\circ}C$, but at 3$0^{\circ}C$ and in control, emergence of workers are remarkably increased from the middle of June and last until July. No new queen emerged at 15$^{\circ}C$, 2$0^{\circ}C$ and $25^{\circ}C$. New queens at 3$0^{\circ}C$ and in control emerged between late in June and early in July. Thus emergence of new queen was temperature dependent.

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Fabrication of polycrystalline 3C-SiC diode for harsh environment micro chemical sensors and their characteristics (극한 환경 마이크로 화학센서용 다결정 3C-SiC 다이오드 제작과 그 특성)

  • Shim, Jae-Cheol;Chung, Gwiy-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.195-196
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    • 2009
  • This paper describes the fabrication and characteristics of polycrystalline 3C-SiC thin film diodes for extreme environment applications, in which the this thin film was deposited onto oxidized Si wafers by APCVD using HMDS In this work, the optimized growth temperature and HMDS flow rate were $1,100^{\circ}C$ and 8sccm, respectively. A Schottky diode with a Au, Al/poly 3C-SiC/$SiO_2$/Si(n-type) structure was fabricated and its threshold voltage ($V_d$), breakdown voltage, thickness of depletion layer, and doping concentration ($N_D$) values were measured as 0.84V, over 140V, 61nm, and $2.7{\times}10^{19}cm^2$, respectively. To produce good ohmic contact, Al/3C-SiC were annealed at 300, 400, and $500^{\circ}C$ for 30min under a vacuum of $5.0{\times}10^{-6}$Torr. The obtained p-n junction diode fabricated by poly 3C-SiC had similar characteristics to a single 3C-SiC p-n junction diode.

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Effects of Annealing Heat Treatment Conditions on Phase Transformation of Nitinol Shape Memory Alloy (어닐링 열처리 조건에 따른 NITINOL형상기억합금의 상변환 특성 연구)

  • Yoon Sung Ho;Yeo Dong Jin
    • Composites Research
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    • v.18 no.2
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    • pp.38-45
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    • 2005
  • Phase transformation behaviors and crystal structures of Nitinol shape memory alloy $(54.5Ni-45.5Tiwt\%)$ are investigated by varying annealing heat treatment conditions through DSC (Differential Scanning Calorimetry) and XRD (X-Ray Diffraction). Annealing heat treatment conditions were considered as heat treated times of 5min, 15min. 30m1n, and 45min, as well as heat treated temperatures of $400^{\circ}C,\;500^{\circ}C,\;525^{\circ}C,\;550^{\circ}C,\;575^{\circ}C,\;600^{\circ}C,\;700^{\circ}C,\;800^{\circ}C,\;and\;900^{\circ}C$ According to the results, annealing heat treatment conditions such as heat treated times and heat treated temperatures were found to affect significantly on phase transformation behaviors and crystal structures of Nitinol shape memory alloy.

Application of carbon-supported PdPt as anode catalysts in PEM fuel cell (PdPt/C 촉매의 고분자전해질 연료전지의 산화극 촉매 적용)

  • Cho, Yong-Hun;Choi, Baeck-Beom;Cho, Yoon-Hwan;Park, Hyun-Seo;Sung, Yung-Eun
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.11a
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    • pp.396-398
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    • 2006
  • PdPt/C (Pd:Pt atomic ratio of around 19:1 60wt, %) 촉매를 고분자전해질 연료전지용 전극 촉매소재의 적용하였다. PdPt/C 촉매를 산화극 촉매로, 환원극 촉매로는 Pt/C 촉매를 사용하고 반대로 산화극 촉매는 Pt/C 촉매, 환원극 촉매로는 PdPt/C 촉매를 사용했을 때, PdPt/C 촉매를 산화극과 환원극 촉매로 동시에 사용했을 때의 고분자전해질 연료전지의 단위전지 성능을 각각 비교하였다. PdPt/C촉매를 산화극에만 적용했을 때에 Pt/C 상용촉매를 산화극과 환원극에 모두 적용했을 때의 성능만큼 좋은 성능을 확인할 수 있었다. 환원극 촉매는 Pt/C를 사용하고 산화극 촉매를 PdPt/C Pt/C Pd/C를 사용하였을 매의 성능을 비교하였다. Pd/C를 산화극 촉매로 사용한 단위전지가 나머지 두 경우의 성능에 비하여 현저히 떨어짐을 확인할 수 있었다. 이는 극소량의 Pt 량을 포함한 PdPt/C 촉매가 고분자전해질 연료전지의 산화극 Pt/C 촉매의 대체촉매로 사용 가능함을 보여준다.

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Fabrication of ceramic fibre composite and improvement of its property (세라믹 섬유 복합체의 제조 및 물성 향상)

  • 김법진;신재혁;신동우;오근호
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.6 no.2
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    • pp.203-212
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    • 1996
  • Applicability of SiC coating through CVD process and PCS(polycarbosilane) impregnation for the oxidation resistance and mechanical properties of C/C composite was studied. The SiC layer coated by CVD was deposited uniformly on the C/C composite, whereas the SiC converted from PCS impregnation wetted around individual carbon fiber. The PCS-impregnated C/C composite exhibited a significant increase of bending strength in comparison with as received C/C composite. This increase in the mechanical property could be attributed to the high bonding strength between fibers due to an impregnated SiC phase. The PCS-impregnated C/C showed 25% improvement in density, 3.5 times higher MOR and 2.8 times higher oxidation resistance compared to the as-received C/C. The increments due to PCS impregnation were more effective than CVD process.

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Cyclic AMP Receptor Protein Adopts the Highly Stable Conformation at Millimolar cAMP Concentration (높은 cAMP 농도에서 cAMP 수용성 단백질의 열 안정화)

  • Kang, Jong-Baek;Choi, Young
    • Journal of Life Science
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    • v.13 no.5
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    • pp.751-755
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    • 2003
  • Cyclic AMP receptor proteins(CRP) activate many genes in Escherichia coli by binding of cAMP with not fully known mechanism. CRP existed as apo-CRP in the absence of cAMP, $CRP;(cAMP)_2$$_2$ at low(micromolar) cAMP concentration, or $CRP;(cAMP)_4$ at high(millimolar) concentration of cAMP. This study is designed to measure the thermal stability of S83G CRP, which substituted glycine for serine at amino acid 83 position, with CD spectrapolarimeter at 222nm by the constant elevation of temperature from $20^{\circ]C\; to\; 90^{\circ}C\; at\; 1^{\circ}C/min$. The non-linear regression analysis showed that melting temperatures were 68.4, 72.0, and $82.3^{\circ}C$ for no cAMP, 0.1mM cAMP, and 5mM cAMP, respectively. Result showed the strong thermal stability of CRP by binding of additional cAMP molecules to region between the hinge region and helix-turn-helix(HTH) motif at 5mM cAMP concentration.

Chemical Vapor Deposition of $\beta$-SiC by Pyrolysis of MTS and Effect of Excess C Sources (MTS의 열분해를 이용한 $\beta$-SiC의 화학증착 및 Excess C 공급원의 영향)

  • 최병진;박병옥;김대룡
    • Journal of the Korean Ceramic Society
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    • v.30 no.1
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    • pp.46-54
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    • 1993
  • $\beta$-SiC was chemically vapor deposited by pyrolysis of MTS+H2 gas mixture. The experiments were conducted in the temperature range of 1100~150$0^{\circ}C$ with a r.f. induction furnace under atmospheric pressure. The IR, XRD, EDS and AES analysis revealed that the free Si was always codeposited with SiC below 140$0^{\circ}C$, regardless of the total flow rate and MTS concentration, whereas $\beta$-SiC single phase was deposited at 150$0^{\circ}C$. C3H8 or CH2Cl2 as an excess C sources, was supplied with MTS in order to obtain stoichiometric SiC at low temperature. With the addition of C3H8 or CH2Cl2, the deposition rate was increased and $\beta$-SiC single phase could be deposited even at temperature as low as 110$0^{\circ}C$. In the absence of C3H8 or CH2Cl2, the microhardness of the layer was quite low (

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