• 전기화학회지
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• 제19권4호
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• pp.123-128
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• 2016

본 연구에서는 poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP)를 나노 크기의 $Al_2O_3$ 세라믹입자와 혼합하여 전기방사법으로 복합 겔 고분자 전해질을 제조하였다. $Al_2O_3$ 세라믹입자를 혼합한 복합 겔 고분자 전해질의 이온전도도는 $9.5{\times}10^{-2}Scm^{-1}$로, 순수한 PVdF-HFP 겔 고분자 전해질보다 높은 이온전도도를 나타내며 전기화학적 안정성도 5.2 V까지 개선하였다. 전기화학적 성능을 분석하기 위해서 $LiNi_{1/3}Mn_{1/3}Co_{1/3}O_2$ (NMC)양극과 함께 전지로 제작되었으며 순수 겔 고분자 전해질과 복합 겔 고분자 전해질 셀은 0.1C-rate에서 각각 $168.2mAh\;g^{-1}$과 $189.6mAh\;g^{-1}$의 방전 용량을 가지며 우수한 수명 특성을 보여 주었다. 따라서 고유전율 세라믹 입자의 복합화는 리튬 이온 겔 고분자 전지의 안정성과 전기화학적 특성을 향상시키는 좋은 대안이 될 것으로 판단된다.

• 한국토양비료학회지
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• 제47권6호
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• pp.540-546
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• 2014

Acid mine drainage sludge (AMDS) has been classified as mine waste and generally deposited in land. For this reason, studies have been conducted to examine the possibility of recycling AMDS as an amendment for heavy metal stabilization in soil. The main objective of this study was to evaluate heavy metal stabilization efficiency of AMDS comparing with the widely used lime stone. Also, optimum mixing ratio was evaluated for enhancing heavy metal stabilization. AMDS and limestone were mixed at the ratio of 0:100, 25:75, 50:50, 75:25, and 100:0 with five different heavy metal solutions ($100mg\;L^{-1}$ of $NaAsO_2$, $CdCl_2$, $CuCl_2$, $Pb(NO_3)_2$, and $ZnSO_4{\cdot}7H_2O$). The amendments were added at a rate of 3% (w/v). In order to determine the stabilization kinetics, samples were collected at different reaction time of 0, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024 minutes. The heavy metal stabilization by AMDS was faster and higher than those of limestone for all examined heavy metals. While limestone showed only 20% of arsenic (As) stabilization after 1,024 minutes, 96% of As was stabilized within 1 minute by AMDS. The highest effect on the stabilization of heavy metal (loid) was observed, when the two amendments were mixed at a ratio of 1:1. These results indicated that AMDS can be effectively used for heavy metal stabilization in soil, especially for As, and the optimum mixing ratio of AMDS and lime was 1:1 at a rate of 3% (w/v).

• 한국정보전자통신기술학회논문지
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• 제13권2호
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• pp.123-128
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• 2020

본 논문에서는 주파수 변화 감지 회로 (FVSC : frequency variation sensing circuit)를 포함하는 부궤환 루프를 가지는 저잡음 위상고정루프를 제안하였다. 위상 고정 상태에서 전압제어발진기의 출력주파수가 변화할 때 주파수 변화 감지 회로는 루프 필터의 커패시터의 전하량을 조절하여 제안한 위상고정루프의 위상잡음과 지터 특성을 개선할 수 있다. 위상고정루프의 출력 주파수가 증가하면 주파수 변화 감지 회로가 루프 필터 커패시터 전하를 감소시킨다. 이는 루프필터 출력 전압을 하강하게 하여 위상고정루프 출력 주파수가 하강하게 된다. 추가된 부궤환 루프는 제안한 위상고정루프의 위상잡음 특성을 더욱 더 좋게 한다. 주파수 변화 감지 회로에 사용된 커패시터 크기는 영점을 결정하는 루프 필터 커패시터 크기와 비교하여도 아주 작은 크기이어서 칩 크기에 영향을 미치지 않는다. 제안된 저잡음 위상고정루프는 1.8V 0.18㎛ CMOS 공정을 이용하여 설계되었다. 시뮬레이션 결과는 273fs 지터와 1.5㎲ 위상고정시간을 보여주었다.

• 한국수정란이식학회지
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• 제26권2호
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• pp.123-128
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• 2011

In vitro maturation and activation of oocytes are primary steps towards biotechnological manipulation in embryology. The objectives of the present study were to determine the oocyte recovery rate per ovary, in vitro maturation rates of oocytes and rates of parthenogenetically activation of matured oocytes in Black Bengal goats. All visible follicles were aspirated to recover follicular fluid from individual ovaries (number of ovaries = 456). The immature cumulus oocyte complexes (COCs; n = 1289) were cultured in tissue culture medium (TCM)-199 supplemented with 10% (v/v) fetal bovine serum (FBS) for 27 hours at $39^{\circ}C$ with 5% $CO_2$ in humidified air. The matured oocytes (n = 248) were activated with 5 ${\mu}M$ ionomycin for 5 minutes followed by treatment with 2 mM 6-dimethylaminopurine (6-DMAP) for 4 hours. After activation, oocytes were cultured for another 14 hours in TCM-199 supplemented with bovine serum albumin (BSA) at $39^{\circ}C$ with 5% $CO_2$ in humidified air. The pronucleus formation in activated oocytes was determined by staining with 1% orcein (whole mount technique). Matured oocytes (n = 176) without activation stimuli were used as control. The mean number of oocytes recovered per ovary was $3.5{\pm}0.5$. The proportion of oocytes matured in vitro, confirmed by the presence of first polar body, was $42.1{\pm}4.7%$. Parthenogenetic activation, evidenced by formation of pronucleus, occurred in $37.2{\pm}15.8%$ of matured oocytes. No pronucleus formation was observed in control oocytes. In conclusion, a combination of ionomycin and 6-DMAP induces activation in one third of Black Bengal goats' oocytes.

• 한국가축번식학회지
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• 제12권1호
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• pp.37-41
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• 1988

These studies were carried out to examine the sex of preimplantation mouse embryo. For the investigation of sex-ration of mouse embryos, morula and blastocysts stage embryos treated with H-Y antiserum (10%, v/v) and FITC anti-mouse-IgG were divided into the positive and negative embryos. Positive and negative identified embryos were observed the viability according to the in vitro cultured and the sex ratio was also investigated by chromosomal analysis. The results obtained in these studies were summarized as follows: 1. Two hundred sixty-seven recovered embryos of morula or blastocyst stage were incubated in medium containing H-Y antiserum and FITC anti-mouse-IgG. Positively or negatively identified embryos were 139 and 128. This trend indicated the approximal sex ratio was 1:1. 2. Sex ratio was measured using the embryos treated with indirect immunofluorescence assay to examine the relationship between embryo developmental stage and sex ratio. Sex ratio of morula stage embryos was 45.2% positive and 54.8% negative, on the other hand, the ratio switched to 56.4% positive and 43.6% negative embryo in blastocyst stage. 3. Fourty-seven positive and 57 negative embryos were obtained out of 104 morula stage embryos treated with indirect immunofluorescence assay. Survived positive or negative embryos during in vitro culture were 42 and 49, respectively out of 47 and 57 embryos. 4. The numbers of negative and positive embryos were 171 and 92 out of 163 blastocyst embryos which were incubated in the medium containing H-Y antiserum and FITC anti-mouse-IgG. The result of karyotype test showed the successful rate of sexing embryo is positive and negative embryos was63.0% (58/92) and 62.0% (44/71). The final female to male ratio within 58 positive embryos was 22.7:77.6, and the ratio of the 44 negative embryos was 77.3:22.7.

• 한국미생물·생명공학회지
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• 제30권2호
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• pp.123-128
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• 2002

토양으로 부터 xylan 분해능이 우수한 Bacillus sp. AMX-4를 분리하고 동정하였는데 분리균의 화학조성은 B. subtilis와 유사성을 보였다. 분리균이 생산하는 xylanase는 50℃와 pH 6에서 최대활성을 보였다. 배지의 부가 탄소원을 첨가하여 Bacillus sp. AMX-4을 배양한 결과 xylose를 첨가한 배지에서 xylanase 생산성이 가장 증가하는 것으로 나타났으며, xylose를 1.5％(w/v)가 되도록 첨가하였을 때 배양상등액의 xylanase 활성이 29.2 U/ml로 약 16배 정도 생산성이 증가하였다. Xylose를 첨가한 배지와 첨가하지 않은 배지에서 Bacillus sp. AMX-4를 배양하여 균의 성장과 효소 생산성을 비교한 결과 xylose를 첨가한 배지에서 효소 생산뿐만 아니라 분리균의 최대 성장정도도 증가한 것으로 보아 xylose는 균의 성장과 xylanase 생합성을 동시에 유도하는 것으로 판단된다. 또한 xylanase는 균의 성장과 연계되어 생산되는 것으로 확인되었다.

• 한국수산과학회지
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• 제47권1호
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• pp.18-22
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• 2014

The antibacterial activities of methanol extracts of 19 commercial herbal medicines were measured against the fish pathogens Vibrio ichthyoenteri and Streptococcus iniae, which cause several fish diseases. Rhus javanica showed the strongest antibacterial activity against V. ichthyoenteri and S. iniae. The methanol extract of R. javanica was extracted further using several organic solvents with different polarities. The extract from the ethyl acetate fraction showed strong activity against both fish pathogens. The minimum inhibitory concentration (MIC) of the R. javanica extract was $32{\mu}g/mL$ for V. ichthyoenteri and $128{\mu}g/mL$ for S. iniae. Further purification and isolation of the active compound (s) responsible for these activities and further study of the synergistic effect using combinations of antibiotics against pathogenic bacteria are needed.

• 전자공학회논문지
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• 제51권9호
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• pp.119-128
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• 2014

본 논문에서는 이전 연구 방법에서의 UV-histogram을 확장하여 적응적 UV-histogram을 제시함으로써, 복잡한 구성의 장면에서 사람의 검출율을 높이는 방법을 제시한다. 제안 방법은 먼저 U-histogram에서 사람 영역을 1차 추출하고, 각각의 레이블링된 U에서 V-histogram을 생성함으로써, 이전 방법에서 구분할 수 없었던 사람 후보 영역을 정확하게 추출한다. 또한 제안 방법은 사람 판정시, 초점거리와 거리에 따라 적응적인 크기를 가지는 오메가 모양의 템플릿을 이용하여 검출의 정확도를 높였으며, 누적 영상을 이용하여 오검출을 템플릿 재매칭 함으로써, occlusion에도 강인한 특성을 가진다. 실험 결과는 Bae의 연구방법에 비하여 복잡한 환경에서 약 15%의 정확도 향상, 80%의 재현율 향상을 보이며, Xia의 연구방법에 비하여 20배 빠른 수행속도를 보여, 제안 방법의 성능이 우수함을 입증한다.

• Journal of Radiation Protection and Research
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• 제41권2호
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• pp.81-86
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• 2016

Background: For positron emission tomography (PET) application, cadmium zinc telluride (CZT) has been investigated by several institutes to replace detectors from a conventional system using photomultipliers or Silicon-photomultipliers (SiPMs). The spatial and energy resolution in using CZT can be superior to current scintillator-based state-of-the-art PET detectors. CZT has been under development for several years at the Korea Atomic Energy Research Institute (KAERI) to provide a high performance gamma ray detection, which needs a single crystallinity, a good uniformity, a high stopping power, and a wide band gap. Materials and Methods: Before applying our own grown CZT detectors in the prototype PET system, we investigated preliminary research with a developed discrete type data acquisition (DAQ) system for coincident events at 128 anode pixels and two common cathodes of two CZT detectors from Redlen. Each detector has a $19.4{\times}19.4{\times}6mm^3$ volume size with a 2.2 mm anode pixel pitch. Discrete amplifiers consist of a preamplifier with a gain of $8mV{\cdot}fC^{-1}$ and noise of 55 equivalent noise charge (ENC), a $CR-RC^4$ shaping amplifier with a $5{\mu}s$ peak time, and an analog-to-digital converter (ADC) driver. The DAQ system has 65 mega-sample per second flash ADC, a self and external trigger, and a USB 3.0 interface. Results and Discussion: Characteristics such as the current-to-voltage curve, energy resolution, and electron mobility life-time products for CZT detectors are investigated. In addition, preliminary results of gamma ray imaging using 511 keV of a $^{22}Na$ gamma ray source were obtained. Conclusion: In this study, the DAQ system with a CZT radiation sensor was successfully developed and a PET image was acquired by two sets of the developed DAQ system.

• 대한화학회지
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• 제35권2호
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• pp.128-134
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• 1991

기존 칼륨이온 선택성 전극의 메트릭스로는 대체로 PVC가 사용되어졌으나, 본 연구에서는 폴리우레탄을 사용하였고, 용매 매개체로는 2-nitropheny-n-alkylate, 감응물질로는 potassium tetraphenyl borate 및 D-18-Crown-6 등을 써서 전극막을 제조하였다. 본 폴리우레탄 메트릭스의 칼륨이온 선택성전극의 수명은 75일로서 PVC 메트릭스의 칼륨이온 선택성 전극에 비하여 한층 더 길었다. 전극전위응답(slope factor)은 직선응답범위(K$^+$ 농도 : $1{\times}10^{-1}\;{\sim}\;1{\times}10^{-4}$ M)내에서 52 mV/decade이었고, 본 전극은 방해이온들 $(NH^{4+},\;Na^{+},\;Li^{+},\;Ca^{2+},\;Mg^{2+},\;Cu^{2+}$)이 존재하는 해수 중의 칼륨이온을 B(Ph)$_4^-$ 표준용액으로 전위차 적정시 종말점을 검출하는데 성공적으로 적용되었다.