• 한국대기환경학회지
• /
• 제26권1호
• /
• pp.94-102
• /
• 2010

Water content of $PM_{2.5}$ (particles in the atmosphere with a diameter of less than or equal to a nominal $2.5{\mu}m$) was estimated by using a gas/aerosol equilibrium model, SCAPE2, for the particles collected at Seoul and Gosan, Korea. From measured and analyzed characteristics of the particles, the largest difference between Seoul and Gosan is the proportions of total ammonia (t-$NH_3$=gas phase $NH_3$+particle phase ${NH_4}^+$), total nitric acid (t-$HNO_3$=gas phase $HNO_3$+particle phase ${NO_3}^-$) and sulfuric acid ($H_2SO_4$). Even though both sites have sufficient t-$NH_3$ to neutralize acidic species such as $H_2SO_4$, t-$HNO_3$, and t-HCl (total chloric acid=gas phase HCl+particle phase $Cl^-$), equivalent fraction of t-$NH_3$ and t-$HNO_3$ are higher at Seoul and $H_2SO_4$ is higher at Gosan. Based on the modeling result, it is identified that the $PM_{2.5}$ at Seoul is more hygroscopic than Gosan if the meteorological conditions are the same. To reduce water content of $PM_{2.5}$, and thus, mass concentration, control measures for ammonia and nitrate reduction are needed for Seoul, and inter-governmental cooperation is required for Gosan.

• 한국식품조리과학회지
• /
• 제7권1호
• /
• pp.45-51
• /
• 1991

1. 유지의 지방산 조성 분석시 GC의 경우 Oleic acid/Elaidic acid를 분리 측정하지 못하였으나 그 외 지방산들(Myristic acid, Palmitic acid, Stearic acid, Linoleic acid, Lindenic acid, Arachidonic acid)에 있어서는 재현성이 높았으며 HPLC는 Stearic acid, Elaidic acid, Linoleic acid Arachidonic acid 검출에 높은 재현성을 나타냈으나 Palmitic acid/Oleic acid를 분리하지 못하였으며 CGC는 Elaidic acid를 제외한 모든 지방산들에 있어서 좋은 측정능력을 보였주었다. 2. 지방산의 cis/trans 기하 이성체의 측정시에는 CGC가 가장 능력이 뛰어났고 HPLC도 양호하였으나 GC는 Oleic acid/Elaidic acid 이성체 측정이 불가능하였다. 또한 각 지방산 분석에 소요된 평균 시간은 GC가 7.21분, CGC가 9.84분, 그리고 HPLC는 24.48분으로서 GC와 CGC의 경우는 비슷하나 HPLC는 다른 기기에 비해 약2.5∼3배의 많은 시간이 소요되었다. 3. 이들 3가지 분석기기로 실제 유지식품인 대두유(CSOY, DSOY)의 지방산조성을 분석한 결과, 정제된 대두유(CSOY)는 Linoleic acid, Oleic acid, Palmitic acid, Linolenic acid가 주요구성 지방산인 반면 Stearic acid는 소량으로 함유되어 있었으며, 미정제 대두유(DSOY)에서는 Linoleic acid, Oleic acid, Palmitic acid, Stearic acid가 주요 구성 지방산이었고 Linolenic acid는 아주 미량 함유되어 있었다. 이때 3가지 분석기기의 대두유의 지방산 분석능력은 표준지방산 분석의 지방산 분석능력은 표준지방산 분석시에 나타난 결과와 동일하였다. 따라서 GC, CGC및 HPLC의 분석특징으로 GC의 경우 분석소요시간이 CGC나 HPLC에 비해 짧은 반면 이성체 분리가 불가능하였으며 HPLC는 분석소요시간이 다른 기기에 비해 다소 긴 반면 이성체 측정이 가능하였고 포화지방산보다는 불포화지방산 측정에 다소 유리하였다. 그리고 CGC의 분석특성에 있어서 재현성, 분석 소요시간 및 이성체 분리능력이 GC나 HPCL에 비해 우수한 것으로 평가되었다.

• 대한화학회지
• /
• 제18권3호
• /
• pp.153-156
• /
• 1974

황산산성에서의 히드라진과 요오드의 반응에 대하여, 기체발생속도를 측정하였다. 이미 보고된 요오등의 소비속도의 경우와 마찬가지로, 히드라진 및 요오드의 농도에 관하여는 1차 반응이며, 반응속도는 요오드화이온의 농도에 역비례한다. 그뿐만 아니라, 요오드으이 소비속도롸 기체 발생속도가 거의 같으므로, 수명이 긴 중간물이 생기지 않는다고 결론지을 수 있다

• Journal of the Korean Wood Science and Technology
• /
• 제42권2호
• /
• pp.157-162
• /
• 2014

This study was conducted to examine the functionality of the fire retardant treated wood. The hygroscopic property, leaching resistance, metal corrosive efficacy and gas toxicity of retardant treated wood were analyzed. Sodium silicate was penetrated to the wood for making fire retardant treated wood. The subsequent treatment agents such as boric acid, ammonium borate, di-ammonium phosphate were treated after sodium silicate treatment due to fixation. As results for the test, the leaching resist was improved by subsequent treatment. The fire retardant combination such as sodium silicate, boric acid and di-ammonium phosphate showed high hygroscopic property, metal corrosive efficacy. The gas toxicity was also satisfied KS standard.

• 한국분말재료학회지
• /
• 제25권5호
• /
• pp.390-394
• /
• 2018

Metallic tantalum powder is manufactured by reducing tantalum oxide ($Ta_2O_5$) with magnesium gas at 1,073-1,223 K in a reactor under argon gas. The high thermodynamic stability of magnesium oxide makes the reduction reaction from tantalum oxide into tantalum powder possible. The microstructure after the reduction reaction has the form of a mixture of tantalum and magnesium oxide, and the latter could be entirely eliminated by dissolving in weak hydrochloric acid. The powder size in SEM microstructure for the tantalum powder increases after acid leaching in the range of 50-300 nm, and its internal crystallite sizes are observed to be 11.5 to 24.7 nm with increasing reduction temperatures. Moreover, the optimized reduction temperature is found to be 1,173 K as the minimum oxygen concentration is approximately 1.3 wt.%.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2007년도 춘계학술대회
• /
• pp.804-807
• /
• 2007

The acid gas removal (AGR) system was designed and installed to remove $H_2S$ in coal syngas in the pilot-scale coal gasification system for producing chemicals like Dimethyl Ether(DME). The syngas from the coal gasification at the rate of $100{\sim120$ $Nm^3$/hr included pollutants such as fly ash. $H_2S$, COS, $NH_3$, etc. The designed temperature and pressure of the AGR system are below 50oC and 8 kg/$cm^2$. Fe-chelate was used as an absorbent. $H_2S$ was stably removed below 0.5 ppm in the AGR system when the concentration of $H_2S$ was $150{\sim}450$ ppm. The pH of Fe-chelate solution was also stably maintained between $8{\sim}9$. FeMgO absorbent was also tested to remove $H_2S$ in the lab-scale AGR system and $H_2S$ was also removed below 0.5 ppm in the initial operation.

• Journal of Pharmaceutical Investigation
• /
• 제40권3호
• /
• pp.155-160
• /
• 2010

A gas chromatographic-mass spectrometric (GC-MS) method was developed for the simultaneous determination of valproic acid (VPA) and its toxic metabolites, 4-ene-VPA and 2,4-diene-VPA in rat plasma. Extraction was performed in weak acidic condition (pH 5.2) to avoid degradation of 4-ene-VPA and 2,4-diene-VPA. The recoveries for 4-ene-VPA and 2,4-diene-VPA were more than 70% and that for VPA was 33-42%. R value for each compounds exceeded 0.998 in calibration curve during all the analysis. Accuracy and precision ranged from 88.3 to 113.2% and from 2.16 to 14.2%, respectively The method was successfully applied to monitor plasma concentrations of VPA, 4-ene-VPA and 2,4-diene-VPA after intravenous administration of VPA at the dose of 100 mg/kg, suggesting that these toxic metabolites may involved in the hepatotoxicity induced by VPA.

• Food Science and Biotechnology
• /
• 제14권2호
• /
• pp.238-241
• /
• 2005

Aroma-active compounds were evaluated from salt-fermented anchovy sauce by solid phase microextraction-gas chromatography-olfactometry (SPME-GC-O) based on sample dilution analysis (SDA). SPME extract from carboxen/polydimethylsiloxane (CAR/PDMS) fiber was the most similar to the original odor of salt-fermented anchovy sauce used for this experiment, followed by divinylbenzene/CAR/PDMS (DVB/CAR/PDMS) fiber. Because salt-fermented anchovy sauce contains 23% NaCl, NaCl concentration of diluent was considered when salt-fermented anchovy sauce was serially diluted. Linear relationship between GC response and sample concentration was observed when diluted with 23% NaCl solution, whereas not observed when diluted with deodorized distilled water. Eleven and 16 aroma-active compounds were detected by SPME-GC-O based on SDA using CAR/PDMS and DVB/CAR/PDMS fibers, respectively. Butanoic acid and 3-methyl butanoic acid showed the highest ${\log}_2SD$ factors for CAR/PDMS and DVB/CAR/PDMS fibers. Dimethyl trisulfide, methional, trimethyl amine, 1-penten-3-ol, and acetic acid were also detected as potent aroma-active compounds.

• 농업과학연구
• /
• 제47권3호
• /
• pp.437-443
• /
• 2020

The aim of this study was to evaluate the effect of Lactobacillus acidophilus probiotic (LAP) product supplementation on the blood profile, fecal noxious gas emission, and fecal shedding of lactic acid bacteria and coliform bacteria in healthy adult Beagle dogs. In total, 14 Beagle dogs with an average initial body weight of 10.19 ± 0.61 kg were randomly assigned into two dietary treatments,with and without LAP supplementation, for a 28-day feeding trial. At the end of the experiment, there was no significant (p > 0.05) difference in the concentration of serum total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), white blood cell (WBC), red blood cell (RBC), blood lymphocyte percentage, fecal hydrogen sulfide (H₂S) and total mercaptans (R.SH) emission, and fecal coliforms counts. However, the serum concentrations of the triglyceride and fecal ammonia (NH₃) emission of the LAP treatment were significantly (p < 0.05) decreased in the group compared with the CON dogs. Fecal total lactic acid bacteria counts were significantly (p < 0.05) increased in the LAP treatment. In conclusion, the supplementation of LAP in Beagle dog diets could decrease the blood triglyceride level and enhance the gut Lactobacillus count which may have positive effects on dogs.

• 박물관보존과학
• /
• 제2권
• /
• pp.51-55
• /
• 2000

강원도(江原道) 원주시(原州市) 부론면(富論面) 법천리고분(法泉里古墳)(4호분(號墳))에서 출토된 생선뼈 중 종류를 확인 할 수 없었던 생선뼈 26점에 대한 잔존지방산 분석을 실시하였다. 앞서 분류한 4종류의 생선(조기, 상어, 준치, 민어)뼈에 대한 잔존지방산 분석 기준데이타와 비교하여 어류종류를 확인하고자 하였다. 분석은 가스크로마토그라피(Gas chromatography)를 이용하여 지방산을 분리하였고, 각각의 함량(含量)을 계산하여 시료별 지방산 분포패턴을 확인하였다. 지방산분포 데이타의 해석을 위해서 다변수분류법(多變數分類法)중 주성분분석법을 이용하였다.