• Journal of Microbiology
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• 제35권2호
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• pp.109-116
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• 1997

An extracellular proteinase of Candida albicans was purified by a combination of 0~75% ammonium sulfate precipitation, DEAE Sepharose Fast Flow ion exchange chromatography, and Sephacryl S-200 HR molecular sieve chromatography. Its mlecular weight was approximately 41 kDa on SDS-PAGE and isoelectric point was 4.4. The enzyme was inhibited by pepstain A. Optimum enzyme activity ranged from pH 2.0 to 3.5 with its maximum at pH 2.5 and a temperature of 45$^{\circ}C$. The addition of divalent cations, $Ca^{2+}$, Zn$^{2+}$ and $Mg^{2+}$, resulted in no significant inhibition of enzymatic activity. However, some inhibitory effects were observed by Fe$^{2+}$, Ag$^{2+}$ and Cu$^{2+}$. With BSA as substrate, an apparent $K_m$ was determined to be 7$\times$10$^{-7}$ M and $K_i$, using pepstatin A as an inhibitor, was 8.05$\times$10$^{-8}$ M. N-terminal amino acid sequence was QAVPVTLXNEQ. Degradation of BSA and fibronectin was shown but not collagen, hemoglobin, immunoglobulin G, or lysozyme. The enzyme preferred peptides with Glu and Leu at the P$_1$ position, but the enzyme activity was highly reduced when the P$_2$ position was phe or pro. This enzyme showed antigenicity against sera of patients with candidiasis.

• 한국자기학회지
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• 제23권6호
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• pp.205-208
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• 2013

${\delta}$E 효과는 재료의 영율(Young's modulus)이 자화 상태에 따라 변화하는 효과를 말한다. 본 연구에서는 두께 $25{\mu}m$, 길이 30 mm의 비정질 리본 2605SC를 폭 3 mm, 5 mm, 8.5 mm로 각각 에칭하여 외부 자기장 세기와 시편의 폭 변화에 따른 영율의 변화를 임피던스 공명 측정을 이용하여 측정하였다. 인가 자기장이 증가함에 따라 영율이 증가하는 것과, 시편의 폭이 넓을수록 시편에 인가되는 유효 자기장이 감소하여 영율이 감소하는 결과를 볼 수 있었고, 단원자 모델로 계산한 결과와 비교적 잘 일치하는 것을 확인하였으며, 외부 자기장 세기에 따라 변화하는 영율(${\delta}$E)의 선형적 변화 영역을 이용한 선형 자기센서 제작 가능성을 확인하였다.

• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2002년도 추계국제학술대회
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• pp.169-169
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• 2002

The mobilizable amount of transition metals is a fraction of the total amount of the metal from urban particulate matter. Although the fraction is small, some metals (Fe, Cu) are the major participants in a reaction that generates reactive oxygen species (ROS), which can damage various biomolecules. Damaging effects of the metals can be measured by the single strand breakage (SSB) of X174 RFI DNA or the carbonyl formation of protein. In another study, we have shown that more metals are mobilized by PM2.5 than by PM10 in general. DNA SSB of >20% for PM2.5 and >15% for PM10 was observed in the presence of chelator (EDTA or citrate)/reductant (ascorbate), compared to the control (<3%) only with the chelator. The carbonyl formation by both PMs was very similar in the presence of the chelator, regardless of the kind of proteins. Compared to the control in the absence of chelator/reductant, 3.3 times and 4.9 times more carbonyl formation for PM2.5 and PM10, respectively, was obtained with BSA in the presence of chelator/reductant, showing that PM10 induced 33% more damage than PM2.5. However, 4.8 times and 1.9 times more carbonyl formation for PM2.5 and PM10, respectively, was observed with lysozyme in the presence of chelator/reductant, showing that PM2.5 induced 250% more damage than PM10. Although different proteins showed different sensitivities toward ROS, all these results indicate that the degrees of the oxidation of or damage to the biomolecules by the mobilized metals were higher with PM2.5 than with PM10. Therefore, it is expected that more metals mobilized from PM2.5 than from PM10, more damage to the biomolecules by PM2.5 than by PM10. We suggest that when the toxicity of the dust particle is considered, the particle size as well as the mobilizable fraction of the metal should be considered in place of the total amounts.

• 한국유기농업학회:학술대회논문집
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• 한국유기농학회 2009년도 하반기 학술대회
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• pp.308-308
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• 2009

유기농액비 자가제조 방법의 표준화를 위해 농가 현황조사를 통해 유기농액비 제조방법을 분류하고 제조 시기별 성분함량 변동상을 분석하였다. 조사대상 액비는 경기 9, 강원 5, 충북, 1, 충남 20, 전남 6, 경북 5, 경남 8 등 총 54종이었다. 자가제조 유기농액비에 사용된 재료는 감, 매실, 복숭아, 사과, 참다래, 토마토, 파프리카, 양파, 파, 인삼, 미나리, 민들레, 쇠비름, 쑥, 익모초, 산야초, 황기, 환삼덩굴, 으름열매, 은행과피, 배 어린 열매, 감껍질, 깻묵, 들깨대, 물미역, 쌀뜨물, 쌀겨, 꽁치, 바다생선 (잡어), 불가사리, 생선부산물(내장, 뼈 등), 액젓부산물(해산물의 뼈가 많이 함유된 물질), 동물뼈(돼지, 닭 등), 골분, 혈분, 천매암, 천일염, 계란껍질, 조개껍질, 게껍질, 새우껍질, 굴껍질, 농가부산물, 음식부산물, 구아노, 들깨 대 숯, 참깨 대 숯 등이었다. 제조방법은 기본재료+물, 기본재료+물+미생물, 기본재료+당밀, 기본재료+당밀+미생물, 기본재료+흑설탕, 기본재료+흑설탕+미생물 등이었다. 유기농액비의 화학적 특성은 다양하였으며, 혈분을 주 원료로 한 유기농액비의 화학성변화는 시간의 경과함에 따라 pH는 4.99에서 3.85로 낮아졌지만, EC, T-C, T-N, $P_2O_5$, $K_2O$, CaO, MgO, $Na_2O$, Fe, Mn, Zn 등은 높아졌다.

• 한국재료학회지
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• 제16권4호
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• pp.248-252
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• 2006

An investigation is reported on the coating of ZnS:Cu,Cl phosphors by $HfO_2$ using atomic layer deposition method. Hafnium oxide films were prepared at the chamber temperature of $280^{\circ}C$ using $Hf[N(CH_3)_2]_4\;and\;O_2$ as precursors and reactant gas, respectively. XPS and ICP-MS analysis showed the surface composition of coated phosphor powder was hafnium oxide. In FE-SEM analysis, the surface morphology of uncoated phosphors became smoother and clearer as the number of ALD cycle increased from 900 to 1800. The photoluminescence intensity for coated phosphors showed $7.3{\sim}13.4%$ higher than that of uncoated. The effect means that the reactive surface is uniformly coated with stable hafnium oxide to reduce the dead surface layer without change of bulk properties and also its absorptance is almost negligible due to ultrathin(nano-scaled) films. The growth rate is about $1.1{\AA}/cycle$.

• 농업과학연구
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• 제39권2호
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• pp.255-261
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• 2012

A bacterium AB-55, isolated from waste mushroom bed of Agaricus bisporus in Sukseong-myeon, Buyeo-gun, Chungcheongnam-do, Korea, was screened onto xylan agar congo-red plate by the xylanolysis method and was used to produce an xylanase in shaker buffle flask cultures containing oat spelt xylans. The phylogenetic analysis using 16S rRNA gene sequence data showed that the strain AB-55 had the highest homology (99.0%) with Bacillus subtilis and it was named as Bacillus subtilis AB-55. A xylanase was purified by ammonium sulfate precipitation (50~80%), gel filtration on sephacryl S-300, and ion exchange chromatography on DEAE sepharose FF. The molecular weight of the xylanase was estimated as 44 kDa by SDS-PAGE. Optimal pH and temperature for the xylanase activity was pH 7 and $50^{\circ}C$, respectively. N-terminal amino acid sequence of the enzyme was identified as Ser-Ala-Val-Lys-His-Gly-Ala-Ile-Val-Phe. The substrate specificity of the enzyme exhibited that it hydrolyzed efficiently oat spelt xylan as well as beechwood xylan, but showed no activity against Avicel and carboxymethyl clellulose (CMC). The enzyme activity was enhanced by $Fe^{2+}$ and $Mn^{2+}$ whereas was entirely inhibited by $Hg^+$.

• Journal of Welding and Joining
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• 제35권2호
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• pp.23-29
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• 2017

Mechanical properties and hardness distributions in arc brazed joints of Dual phase steel using Cu-Al insert metal were investigated. The maximum tensile shear load was 10.4kN at the highest brazing current. It was about 54% compared to tensile load of base metal. This joint efficiency is higher than that of joint of DP steel using Cu-based filler metals which are Cu-Si, Cu-Sn. Fracture positions can be divided into two types. Crack initiation commonly occurred at three point junction among upper sheet, lower sheet and the fusion zone. However crack propagations were different with increasing the brazing current. In case of the lower current, it instantaneously propagated along with the interface between fusion zone and upper base material. On the other hand, in case of higher current, a crack propagation occurred through fusion zone. When the brazing current is low (60, 70A), the interface shape is flat type. However the interface shape is rough type, when the brazing current is high (80A). It is thought that the interface shapes were the reason why the crack propagations were different with brazing current. The interface was the intermetallic compounds which consisted of $(Fe,Al)_{0.85}Cu_{0.15}$ IMC formed by crystallization at $1200^{\circ}C$during cooling. Therefore the maximum tensile shear load and the fracture behavior were determined by a interface shape and effective sheet thickness of the fracture position.

• 자원리싸이클링
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• 제8권5호
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• pp.51-58
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• 1999

석탄화력 발전소에서 발생하는 수백만 톤의 석탄회는 콘크리트 혼화재 및 건축자재로 재활용이 가능함에도 불구하고 과다한 미연탄소 함량으로 인해 대부분 회사장(Ash Pond) 되는데, 이로 인해 환경오염유발, 회사장 포화에 따른 발전소의 수명 감소, 그리고 재활용 가능한 자원의 낭비와 같은 문제가 발생한다. 본 연구는 석탄회 내의 미연탄소분을 분리하여 미연탄소분 함량이 낮은 고순도 석탄회를 회수하기 위해 직류관 믹서(In-Line Mixer) 발생기키는 역류형 컬럼부선기를 이용하였다. 이때 입자 표면에 소수성의 특성을 강화시키는 포스제의 증가에 따른 석탄회와 미연탄소 입자의 분리 특성을 분석하였다. 석탕회 톤당 8ι의 포수제를 사용한 역류형 컬럼 부선기를 이용하여 미연탄소분 함유량이 7%인 석탄회를 분리 실험한 결과 미연탄소분 함유량 0.5%인 고순도 석탄회를 88.2% 회수하였다. 그리고 질량 평균입경이 21.2$mu extrm{m}$인 석탄회를 분리 실험하여 입도를 분석한 결과 분리 정도에 따라 입도는 뚜렷하게 구별되어 나타났는데, 분리효율이 증가할수록 정제 석탄회의 경우 입도는 조대해져 입도 분포의 양극화 현상이 뚜렷하게 나타났다. 포수제의 투입량이 증대함에 따라 미연탄소 입자의 계면에 소수성이 강화되어 분리 특성이 향상되었으며, 이때 회수한 고순도 석탄회의 입도는 미세화 되는 경향이 나타났다.

• 자원리싸이클링
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• 제8권5호
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• pp.44-50
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• 1999

동 매트 중에 함유된 불순물 중 단순한 산화정련으로는 제거하기 어려워 제련 후 조동에 함유되어 동의 순도와 기계적 성질을 저하시키는 Ni와 Sb를 매트제련 동안에 제거하기 위한 기초 자료를 제시하고자 공기 송풍에 의한 합성 동 매트의 용련 반응을 통하여 반응 생성물인 매트와 슬래그 그리고 조동에 함유된 Ni와 Sb의 거동 및 상호 연관성을 조사하였다. 공기 송풍에 따른 합성 매트의 용련동안 생성된 반응 생성물에 대한 Ni와 Sb의 분배비로부터 Sb가 Ni과 공존 시 Ni의 슬래그화를 촉진하는 역할을 하며, 또한 Ni은 Sb와 공존시 조동 중으로의 Sb 이동을 저해하고 슬래그화를 촉진시키는 것으로 나타났다. 따라서 Ni와 Sb의 슬래그화를 유도하기 위해서는 Ni와 Sb의 공존이 필요한 것으로 생각된다.

• 한국축산식품학회지
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• 제39권5호
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• pp.756-767
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• 2019

This study aimed to evaluate the effect of doneness on the microbial, nutritional, and quality characteristics of 1.5 cm- and 2.0 cm-thick pork neck steaks. Pork neck meat was obtained within 24 h after slaughtering, cut into 1.5 cm- and 2.0 cm-thick slices (n=5), packed in LLD-PE wrap, and stored at $4{\pm}2^{\circ}C$ for 7-10 days until aerobic plate counts (APC) reach 5.51-6.50 Log CFU/g. Then, the pork meat was cooked on a frying pan till it was medium-rare, medium, or well-done. The microbial inhibition rates of the 1.5 cm- and 2.0 cm-thick steak in medium-rare state were 58.26% and 51.70%, respectively, whereas it was 100% for medium-done pork steak of either thickness. The total calories of the 1.5 cm- and 2.0 cm-thick well-done pork steaks were 643.61 kcal/100 g and 675.00 kcal/100 g, respectively, which was higher than that in medium-rare and medium-done steaks. The retention ratios for Fe and K in the well-done steak were significantly lower than those in the medium and medium-rare steak of either thickness (p<0.05). The shear force of the medium-rare and medium steak did not differ, whereas that of the well-done steak was significantly higher than that of the medium-rare steak of either thickness (p<0.05). We observed that the well-done pork steak had tough texture, low mineral content, and high calories. Therefore, consumption of medium and medium-rare pork is more beneficial than that of well-done pork.