• 한국대기환경학회지
• /
• 제10권1호
• /
• pp.24-31
• /
• 1994

Hourly variation of gaseous nitrous acid( HNO$_2$) concentration in Seoul air was monitored from Jan. 11 to SeP. 12, Nitrous acid concentration was determined by DS/IC over nine months of observation, HNO$_2$ range from 0.04 ppb to 5.5 ppb. Gor-tex tube as gaseous HNO$_2$generator in this study is thought to be more convenient and reproducible device than previous generator. As a result of NaOH instead of Na$_2$ CO$_3$/NaHCO$_3$ solution as the IC eluent, we could obtain more stable baseline. The concentration of the NaOH eluent was 15 mM . The limit of detection(3$\sigma$) of the liquid- Phase and gas phase nitrous acid of this method are 1.1ng/$m\ell$ , 0.04 n $\ell$ / $\ell$, respectively. The precisions evaluated by 10 replicate analysis of standard solution and standard gas generated are $\pm$1.59, $\pm$2. 89% RSD, respectively. Due to the lack of standard material for air, direct assessment of the accuracy was not possible. This study was applied to the analysis of Seoul ambient air and their results are reported herein.

• 한국식품영양과학회지
• /
• 제22권5호
• /
• pp.629-635
• /
• 1993

정어리 유(油)를 추출 분리하기 위하여 초임계 탄산가스를 용매로하여 추출을 시도하였다. 초임계 탄산가스의 추출조에서의 조건은 추출압력은 5,000~8,000psig. 추출온도는 50~$80^{\circ}C$로 하였을때 탄산가스의 흐름과 확산이 좋았다. 그러므로 평형 용해도는 가스의 유속이 높을때 추출조에서 쉽게 일어난다. 이러한 추출조건하에서 온도 $60^{\circ}C$, 압력 6,000psig. 일때 추출효과가 가장 좋았다. 초임계탄산가스를 추출된 정어리 유는 핵산으로 추출한 것보다 색소가 약하고 냄새도 적었으며 인의 함량은 낮았다. 추출장치에서 분획한 결과 eicosapentaenoic acid($C_{20-5}$)가 90.5%까지 분리되었다.

• 한국표면공학회지
• /
• 제53권3호
• /
• pp.87-94
• /
• 2020

Herein, sulfonated carbon nanotubes (CNT) have been prepared in dilute sulfuric acid (H₂SO₄) via a novel sulfonation approach based on gas-liquid interfacial plasma (GLIP) at room temperature. The sulfonic acid groups and total acid groups densities of CNT after GLIP treatment in 2 M H₂SO₄ for 45 min can reach to 0.53 mmol/g and 3.64 mmol/g, which is higher than that of sulfonated CNT prepared under 0.5 M / 1 M H₂SO₄. The plasma sulfonated CNT has been applied as catalysts for the conversion of microcrystalline cellulose to glucose. The effect of hydrolysis temperature and hydrolysis time on the conversion rate and product distribution have been discussed. It demonstrates that the total conversion rate of cellulose increasing with hydrolysis temperature and hydrolysis time. Furthermore, the GLIP sulfonated CNT prepared in 2 M H₂SO₄ for 45 min has shown high catalytic stability of 85.73 % after three cycle use.

• 한국환경과학회지
• /
• 제23권10호
• /
• pp.1693-1701
• /
• 2014

A rapid and simple method for the quantitative determination of volatile fatty acids (VFAs; propionic acid, n-butyric acid, i-valeric acid and n-valeric acid) and indoles (phenol, p-cresol, 4-ethyl phenol, indole and skatole) in pig slurry and dog excrement using solid-phase micro-extraction (SPME) coupled to gas chromatography was evaluated. $50/30{\mu}m$ DVB/CAR/PDMS (Divinylbenzene/Carboxen/Polydimethylsiloxane) fiber was used to extract the target compounds in aqueous media. Sample amount and adsorption time was standardized for the routine analysis. Detection limits were from 0.11 to $0.15{\mu}gL$ for VFAs and from 0.12 to $0.28{\mu}gL$ for indoles and the correlations observed ($R^2$) were 0.975~1.000. This method was applied to the pig slurry, fertilizer, compost and dog excrement. In nearly all cases, the indoles were detected in concentrations of higher than their limits of detection (DOLs). But the VFAs in swine manure were below their DOLs.

• 자원리싸이클링
• /
• 제12권2호
• /
• pp.36-44
• /
• 2003

전구용 필라멘트 제조 공정에서 발생되는 Mo함유 폐산 내에 암모니아 가스를 취입하여 유가금속인 Mo를 암모늄테트라몰리브데이트($_3$.2NH$4MoO_3$.$H_2$O) 형태로 침전 회수하고, 여과 후 발생되는 중화 여액을 활용하기 위한 연구를 수행하였다. 암모니아 중화법을 이용한 Mo 회수공정에 있어 다양한 공정 변수들에 의한 제품의 회수율, 순도, 입도 등 특성을 평가하였으며, 그 결과로부터 Mo 염의 회수율 99.5% 이상, 순도 99.5% 이상을 확보하기 위한 최적 조업조건을 도출하였다. Bench 및 Pilot규모의 실험을 통하여 상업화 가능성을 확인하였으며, 폐산의 중화반응 후 발생된 여액은 엽면시비용 액상 복합비료의 원료로 사용 가능함을 확인하였다.

• 한국약용작물학회지
• /
• 제16권5호
• /
• pp.301-305
• /
• 2008

수집종 아주까리 40종의 유전자원을 농촌진흥청 농업생명공학연구원 유전자원과로부터 분양받아 바이오디젤 가능 작물로서 조지방 및 지방산 분석결과는 다음과 같다. 수집종 아주까리 종자의 gas chromatogram은 6개의 피크를 보였고, ricinoleic acid의 retention time은 12.7분대이었다. 아주까리 수집종의 평균 기름 함량은 $44.6{\sim}49.4%$이었으며, 최저 41.4%와 최고 52.2%로 10.8%의 차이가 있었다. 지방산 조성은 불포화지방산이 97.6%로 대부분이었으며, 포화지방산은 2.4% 정도로 낮은 함량을 보였다. 지방산 조성은 87.3%가 ricinoleic acid이었으며, oleic acid와 linoleic acid가 각각 4.6%, 5.2%이었다. palmitic acid와 stearic acid의 함량은 1% 내외로 차이가 미미하였고, linolenic acid의 함량은 0.6% 정도로 가장 낮았다.

• 한국식품영양과학회지
• /
• 제13권4호
• /
• pp.406-412
• /
• 1984

잣(Pinus koraiensis S & Z)에서 얻은 총지질 성분을 silicic acid column chromatography에 의해 중성지질, 당지질, 인지질로 분획 정량하고, 다시 이 분획된 성분을 thin layer chromatography 로써 재분리시켜 구성성분들을 분별하고 scanner에서 정량하였으며, 각 획분별 지방산 조성을 gas chromatography로써 분석한 결과는 다음과 같다. 1) 잣지질의 구성은 중성지질이 총지질의 $95.9{\sim}96.7%$, 당지질이 $2.5{\sim}3.2%$, 인지질이 $0.8{\sim}0.9%$였으며, 중성지질에서는 triglyceride(80.8%), diglyceride(6.3%), free fatty acid(5.2%), sterol(4.6%) ,sterol ester 및 hydrocarbon 등이 분별 정량되었으며, 이 중 triglyceride가 주된 물질이었다. 당지질에서는 monogalactosyl diglyceride 및 esterified sterylglycoside(23.5%), cerebroside 및 steryl glycoside(7.8%), digalactosyl diglyceride(2.3%) 등이 분별정량되였고, 인지질의 획분에서는 phosphatidyl cho-line(40.2%), phosphatidyl ethanolamine(19.4%), phosphatidyl inositol(7.3%), lysophosphatidyl choline(5.8%), phosphatidyl serine(2.6%) 등이 분별 정량되었다. 2) 각 분획된 지질의 지방산 조성은 중성지질의 경우 linoleic acid(48.7%), oleic acid(28.8%), arachidic acid(14.4%), palmitic acid(5.7%), stearicacid(1.84%), linolenic acid(0.7%), myristic acid(0.1% 이하), lauric acid(0.1% 이하) 등이 분리 정량되었으며, 당지질과 인지질에서도 linoleic acid, oleic acid등이 주성분으로 이루어져 있었다. 그러나 인지질의 경우 palmitic acid(17.7%)와 stearic acid(6.0%)의 함량이 다른 지질획분에 비해 다소 많았다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제19권4호
• /
• pp.587-592
• /
• 2006

This study was conducted to evaluate the effects of supplementation with bacillus-based probiotic (Bacillus subtilis, $1.0{\times}10^7CFU/g$; Bacillus coagulans, $2.0{\times}10^6CFU/g$ and Lactobacillus acidophilus, $5.0{\times}10^6CFU/g$) on finishing pigs growth performance, nutrients digestibility, blood characteristics and fecal noxious gas content and to determine the optimal addition level of this probiotic preparation. A total of forty eight pigs with an initial body weight (BW) of $90.60{\pm}2.94kg$ were allotted to three dietary treatments (four pigs per pen with four pens per treatment) according to a randomized complete block design. Dietary treatment included: 1) CON (basal diet); 2) BP1 (basal diet+bacillus-based probiotic 0.1%) and 3) BP2 (basal diet+bacillus-based probiotic 0.2%). The experiment lasted 6 weeks. Through the entire experimental period, ADG was improved by 11% (p<0.05) in pigs fed diets supplemented with 0.2% bacillus-based probiotic compared to pigs fed the basal diet. ADFI and gain/feed were not affected by the treatments (p>0.05). Supplementation of bacillus-based probiotic did not affect either DM and N digestibilities or blood characteristics (p>0.05) of pigs. Fecal ammonia nitrogen ($NH_3$-N) measured at the end of experiment was reduced (p<0.05) when pigs were fed the diet with 0.2% bacillus-based probiotic. Fecal butyric acid concentration also decreased significantly (p<0.05) whereas acetic acid and propionic acid concentrations were not affected (p>0.05) when pigs were fed diets with added bacillus-based probiotic. In conclusion, dietary supplementation of bacillus-based probiotic can increase growth performance and decrease fecal noxious gas content concentration.

• 한국환경과학회지
• /
• 제25권8호
• /
• pp.1207-1212
• /
• 2016

The objectives of this study were to evaluate the effect of replacing 40% corn meal with three different types of barley (Youngyang, Wooho, and Yuyeon) on the chemical compositions, microbial indices, gas emission, and volatile fatty acid (VFA) content in feces of growing pigs. Sixteen pigs (Landrace ${\times}$ Yorkshire ${\times}$ Duroc) with an initial average body weight of $71{\pm}2kg$ were maintained in metabolic cages and randomly allotted to four treatments containing different sources of barley, for 23 days. The treatment with three different barley types replacing 40% ground corn showed no effect (P>0.05) on fecal chemical compositions, microbial indices, gas emission, and VFA. However, some differences (P<0.05) were noted in the chemical compositions of crude fiber and ash, and in the levels of Lactobacillus and Salmonella in the feces of the growing pigs. In conclusion, methane and hydrogen sulfide decreased by replacing 40% corn meal with Youngyang and Wooho barley, respectively.

• 멤브레인
• /
• 제3권2호
• /
• pp.60-69
• /
• 1993

BTDA-BAPP, DSDA-BAPP, BTDA-4,4'ODA의 폴리아믹산(PAA)으로 막을 주조하고 부분이미드화하여 산소와 질소의 투과특성을 조사하였다. 가열이미드화로 이미드화가 증가할수록 투과속도는 초기에 증가하여 최고점을 나타내고 감소하였다. 가열이미드화할 때 ?에는 PAA 수소결합의 소실로 기체투과가 증가하나 이미드화가 증가하면 치밀화로 인하여 기체투과 감소효과가 커지는 것으로 추정되었다. BTDA-BAPP, DSDA-BAPP, BTDA-4,4'-ODA는 각각 이미드화율 37%, 47%, 55%일때 최고투과계수 8.3, 0.3, 0.8 barrer을 나타내었다. 그러나 투과선택도는 이미드화와 무관하게 거의 일정하였다.