• 에너지공학
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• 제21권3호
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• pp.272-279
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• 2012

정부의 온실가스 감축목표에 따라 건축물 부분은 26.9%가 할당 되었다. 신규 및 기존 주택에 대해 저에너지 지속 가능한 건축물의 변화는 과제이자 필수 불가결한 문제로 대두 되었다. 신축 건축물은 각종 제도와 규제완화로 저탄소 지속가능한 에너지 변환을 유도하고 있으나 기존건축물 670만동에 대해서는 전체 감축 목표는 나와 있는데 감축방안에 대한 기준이나 방향 제시가 부족한 것이 현실이다. 본 연구는 선정 대상 건축물을 직접 방문하여 현황을 조사하고 적용 기술요소를 반복 시뮬레이션 하여 가장 경제적이고 효과적인 녹색기술 개선책을 제시 하고자 한다.

• Plant Biotechnology Reports
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• 제3권4호
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• pp.333-340
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• 2009

Developmental anomalies in the plumule meristem of peanut (Arachis hypogaea L.) somatic embryos resulted in poor shoot differentiation and reduced plant recovery. Existing meristems with caulogenic potential have never been tested for embryogenesis in peanut. The present experiment was designed to test the mature zygotic embryo axis derived plumule with three meristems for somatic embryogenesis. Embryogenic masses and embryos developed from the caulogenic meristems in the axils. Exposure of 2 weeks in primary medium with $90.5{\mu}M$ 2,4-D suppressed the shoot tip differentiation temporarily which then regained the ability to form the shoot on withdrawal of 2,4-D. Exposure of 4 weeks in primary medium with $90.5{\mu}M$ 2,4-D suppressed the shoot tip differentiation irreversibly. No shoot formation was noted from the tips in any of the cultures which were in secondary medium with $13.6{\mu}M$ 2,4-D. Development of somatic embryos directly from axillary meristems was confirmed histologically. Conversion frequency of these embryos was 11%. Thus, in this report, we describe a method to obtain somatic embryos from the determined organogenic buds of the axillary meristem, by culturing the nodal explant vertically on embryo induction medium. It also displays the possibility of obtaining both embryogenic and organogenic potential in two parts of the same explant simultaneously. The possibility of extending this approach for genetic transformation in in vivo system through direct DNA delivery or Agrobacterium injection in meristems can also be explored. Using Agrobacterium rhizogenes, we have demonstrated the possibility of gene transfer in the axillary meristems of seed-derived plumule explant.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.208-209
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• 2011

In this work, we developed self-assembled monolayers (SAMs) of alkanethiols on gold that can release amine groups, when an electrical potential was applied to the gold. The strategy was based on the introduction of the electroactive carbamate group, which underwent the two-electron oxidation with simultaneous release of the amine molecules, to alkanethiols. The synthesis of the designed thiol compounds was achieved by coupling isocyanate-containing compound with hydroquinone. The electroactive thiols were mixed with hydroxyl-containing alkanethiol [$HS(CH_2)_{11}OH$] to form mixed monolayers, and cyclic votammetry was used for the characterization of the release. The mixed SAMs showed a first oxidation peak at +540 mV (versus Ag/AgCl reference electrode), demonstrating irreversible conversion from carbamate to hydroqinone with simultaneous release of the amine groups. The second and third cycles showed typical reversible redox reaction of hydroquinone and quione: the oxidation and reduction occurred at +290 mV and -110 mV, respectively. The measurement of ToF-SIMS further indicates that electrochemical-assisted chemical reaction successfully released amine groups. This new SAM-based electrochemistry would be applicable for direct release of biologically active molecules that contain amine groups.

• Current Photovoltaic Research
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• 제6권1호
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• pp.21-26
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• 2018

Beside several advantages, the PV power generation as a clean energy source, is still below the supply level due to high power generation cost. Therefore, the interest in fabricating low-cost thin film solar cells is increasing continuously. $Cu_2O$, a low cost photovoltaic material, has a wide direct band gap of ~2.1 eV has along with the high theoretical energy conversion efficiency of about 20%. On the other hand, it has other benefits such as earth-abundance, low cost, non-toxic, high carrier mobility ($100cm^2/Vs$). In spite of these various advantages, the efficiency of $Cu_2O$ based solar cells is still significantly lower than the theoretical limit as reported in several literatures. One of the reasons behind the low efficiency of $Cu_2O$ solar cells can be the formation of CuO layer due to atmospheric surface oxidation of $Cu_2O$ absorber layer. In this work, atomic layer deposition method was used to remove the CuO layer that formed on $Cu_2O$ surface. First, $Cu_2O$ absorber layer was deposited by electrodeposition. On top of it buffer (ZnO) and TCO (AZO) layers were deposited by atomic layer deposition and rf-magnetron sputtering respectively. We fabricated the cells with a change in the deposition temperature of buffer layer ranging between $80^{\circ}C$ to $140^{\circ}C$. Finally, we compared the performance of fabricated solar cells, and studied the influence of buffer layer deposition temperature on $Cu_2O$ based solar cells by J-V and XPS measurements.

• 한국작물학회지
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• 제30권1호
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• pp.53-62
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• 1985

Abscisin산(ABA)의 방사면역측정법을 이용하여 발아과정에 있는 수도에 있어서 ABA함량이 어떻게 변동되는가를 구명하였다. 수도종자중에 함유된 ABA함량은 동진벼에 있어서는 76.5ng/g 건물중이었고 삼강벼는 91.1ng/g 건물중이었다. 발아중에 있는 수도의 ABA함량은 종자 침지후 24시간내에 크게 감소되었으며 이와같은 ABA감소율은 침지온도와 발아중 수분흡수율에 유의한 정의 상관관계를 나타냈다. 수도발아중 ABA의 감소는 조직내 ABA가 침지액중으로 일부 용출되고 일부는 조직내에서 다른 화합물로 대사되는 것에 기인함을 알 수 있었다. 수도의 발아는 체내의 함량이 일정수준 이하에서만 일어나며 발아중 ABA함량의 감소율이 수도의 품종간 저온 발아성과도 관련이 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.395-398
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• 2002

Many research group started study to develope x-ray detector using thin film transistor from 1970. But realization of TFT based x-ray detector development was caused by progress of thin film transistor liquid crystal display(TFTLCD) device technology in 1990. The main current of TFT technology is display device. Research results expend TFT technology field from display device to sensor manufacture technology. These days many research group in the world realize various digital x-ray detector. In this study, We compare discharge erasing method to visible light erasing method in a-Se based digital x-ray detector. Visible light erasing method is known reset process in direct conversion x-ray detector. Digital x-ray detector using visible light erasing method is not adaptive for conventional x-ray device, because of its thickness. And it is not avaliable for real-time imaging for digital fluoroscopy, because of its long reset time. In this study we overcome these limitations and show new idea for real-time imaging method.

• Asian-Australasian Journal of Animal Sciences
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• 제33권8호
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• pp.1233-1241
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• 2020

Objective: The present investigation was aimed to explore the potential of lactobacilli for conjugated linoleic acid (CLA) production, isolated from rumen fluid samples of lactating goats. Methods: A total of 64 isolates of lactobacilli were obtained using deMan-Rogosa-Sharpe (MRS) agar from rumen fluid of goats and further subjected to morphological and biochemical characterizations. Isolates found as gram-positive, catalase negative rods were presumptively identified as Lactobacillus species and further confirmed by genus specific polymerase chain reaction (PCR). The phylogenetic tree was constructed from the nucleotide sequences using MEGA6. Results: Out of the 64 isolates, 23 isolates were observed positive for CLA production by linoleate isomerase gene-based amplification and quantitatively by UV-spectrophotometric assay for the conversion of linoleic acid to CLA as well as gas chromatography-based assay. In all Lactobacillus species cis9, trans11 isomer was observed as the most predominant CLA isomer. These positive isolates were identified by 16S rRNA gene-based PCR sequencing and identified to be different species of L. ingluviei (2), L.salivarius (2), L. curvatus (15), and L. sakei (4). Conclusion: The findings of the present study concluded that lactic acid bacteria isolated from ruminal fluid samples of goat have the potential to produce bioactive CLA and may be applied as a direct fed microbial to enhance the nutraceutical value of animal food products.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.99.1-99.1
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• 2012

The thin-film photovoltaic absorbers (CdTe and $Cu(In,Ga)Se_2$) can achieve solar conversion efficiencies of up to 20% and are now commercially available, but the presence of toxic (Cd,Se) and expensive elemental components (In, Te) is a real issue as the demand for photovoltaics rapidly increases. To overcome these limitations, there has been substantial interest in developing viable alternative materials, such as $Cu_2ZnSnS_4$ (CZTS) is an emerging solar absorber that is structurally similar to CIGS, but contains only earth abundant, non-toxic elements and has a near optimal direct band gap energy of 1.4 - 1.6 eV and a large absorption coefficient of ~104 $cm^{-1}$. The CZTS absorber layers are grown and investigated by various fabrication methods, such as thermal evaporation, e-beam evaporation with a post sulfurization, sputtering, non-vacuum sol-gel, pulsed laser, spray-pyrolysis method and electrodeposition technique. In the present work, we report an alternative aqueous chemical approach based on chemical bath deposition (CBD) method for large area deposition of CZTS thin films. Samples produced by our method were analyzed by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, absorbance and photoluminescence. The results show that this inexpensive and relatively benign process produces thin films of CZTS exhibiting uniform composition, kesterite crystal structure, and some factors like triethanolamine, ammonia, temperature which strongly affect on the morphology of CZTS film.

• Animal cells and systems
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• 제10권4호
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• pp.211-217
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• 2006

Heavy metals are well known as important environmental pollutants and also considered as endocrine disrupters. This study was performed to evaluate the direct effects of heavy metals such as cadmium (Cd), zinc (Zn), mercury (Hg), lead (Pb), cobalt (Co), and arsenic (As) on the various steroidogenic enzymes in frog ovarian follicles. Ovarian follicles from Rana catesbeiana were isolated and cultured for 18 hours in the presence of frog pituitary homogenate (FPH, 0.05 gland/ml) or various steroid precursors with or without heavy metals (0.01-100 ${\mu}M$), and steroid levels in the follicle or culture medium were measured by radioimmunoassay (RIA). Thus, the steroidogenic enzyme activities were indirectly evaluated by measuring the converted steroid levels from the added precursor steroid. Among heavy metals, Hg, Cd and Zn significantly inhibited FPH-induced pregnenolone ($P_5$) production by the follicles ($EC_{50},\;4.0{\mu}M,\;25.6{\mu}M\;and\;5.7{\mu}M$, respectively ), and also suppressed the conversion of testosterone (T) to estradiol $17{beta}\;(E_2)\;(EC_{50},\;4.2{\mu}M,\;7.5{\mu}M\;and\;80.0{\mu}M) while Pb, Co and As are not or less effective in the inhibition. Other enzymes such as $C_{17-20}$ lyase and $17{\beta}$-hydroxysteroid dehydrogenase ($17{\beta}$-HSD) were suppressed only in the high concentration of Hg, Cd and Zn. Taken together, these data demonstrate that cytochrome P450 side chain cleavage (P450scc) and aromatase are much more sensitive to heavy metals than other steroidogenic enzymes and Hg, Cd and Zn show stronger toxicity to follicles than other heavy metals examined.

• 한국지능시스템학회논문지
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• 제20권5호
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• pp.710-715
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• 2010

최근 풍력발전 시스템은 가장 빨리 발전하고 있는 신재생 에너지원중 하나로 각광을 받고 있으며, 풍력발전 시스템의 주된 관심사는 어떻게 광범위한 풍속의 변화에서도 효율적으로 시스템을 동작시키는 가에 있다. 일반적으로 풍속은 풍력발전시스템의 동특성에 큰 영향을 미치는 요소이다. 따라서 많은 풍력발전 제어 알고리듬은 성능향상을 위해 풍속의 측정을 요구하게 된다. 그러나 불행히도 풍속계와 같은 센서에 의한 실효 풍속의 정확한 측정은 어려운 실정이며 따라서 제어 시스템의 동작을 위해 풍속은 여러 가지 기법을 통해 추정되고 있는 실정이다. 이에 본 연구에서는 칼만 필터 및 신경망에 기반한 새로운 형태의 풍속 추정 기법을 제안하고 제안된 기법의 유용성 확인을 위해 다양한 형태의 시뮬레이션을 수행하고자 한다.