• 대한화학회지
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• 제30권5호
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• pp.488-492
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• 1986

경북 원성군 감포 78에서 산출되는 벤토나이 중 몬모리노나이트를 분리하여 Ca, Mg-형을 NaCl용액으로 처리하여 Na-형 몬모리노나이트를 만들었다. 이때 가장 적당한 조건은 0.05M NaCl용액으로 80${\circ}C$에서 24시간 반응시켜 치환되는 $Ca^{2+}$, $Mg^{2+}$량을 EDTA로 적정하여 양이온 교환 용량을 구하였다. Na-형에 $Ln^{3+}$이온용액과 같은 조건하에서 반응시켜 $Ln^{3+}$-형 몬모리노나이트를 만들었다. 치환되는 량은 $Ln^{3+}$이온들의 이온 크기에는 무관함을 알 수 있었고, X-선 회절 실험결과 순수한 몬모리노나이트를 얻을 수 있음을 밝혔고, 또한 $Ln^{3+}$형은 새로운 결정모양이 되는 것을 알 수 있었다. 이는 단순한 틈새끼우기 반응이 아니 새로운 결정형이 생성됨을 알 수 있다.

• 공업화학
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• 제2권4호
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• pp.385-392
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• 1991

전하량적정법에 의해 $Ni_{1-x}O$의 비화학양(nonstoichiometry)를 측정하였고 결함모델을 확인하였다. 0.1-0.21atm의 산소분압과 1123-1198K의 온도범위에서 $Ni_{1-x}O$의 비화학양은 $Po_2{^{1/4}}$에 비례하였다. 이러한 산소분압의 의존성으로부터 $Ni_{1-x}O$의 주 결함은 singly 이온화한 Ni 빈자리임을 확인할 수 있었다. T=1173K와 $Po_2=0.21atm$인 조건에서 $x=1.21{\times}10^{-4}$의 값을 가졌다. 제안된 결함모델로 부터 결함의 표준생성엔탈피를 계산하였는데 0.95 eV의 값을 가졌다. 1248K 이상의 온도에서는 doubly 이온화된 빈자리로의 전이가 나타나기 시작하였다.

• 콘크리트학회논문집
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• 제17권5호
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• pp.821-828
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• 2005

To investigate the role of RH and temperature on the transport of chloride in the concrete, two groups of specimens were configured. For both groups, mix design was based on w/c=0.45, $400kg/m^3$ cement, $794kg/m^3$ fine aggregate and $858kg/m^3$ coarse aggregate. After specimen fabrication these were exposed to four different RH (35, 55, 75 and $95\%$ RH) and temperature (0, 20, 30 and $40^{\circ}C$) conditions. After 3 and 6 months $15\%$ NaCl exposure 5mm cores were taken. These cores were sliced and individual cores were ground to powder. In addition, to evaluate the effect of temperature on the chloride binding some powder samples were leached in the each of four temperature chambers. Chloride titration fur these was performed using FDOT acid titration method. Based upon the resultant data conclusions were reached regarding that 1) effective diffusion coefficient, $D_e$, increased with increasing exposure RH, suggesting that the size and number of water paths increased with elevated moisture content in the specimens, 2) $D_e$ increased with increasing temperature in the range of 0 to $40^{\circ}C$ possibly by elevated thermal activation of chloride ions and reduced chloride binding at higher temperature, 3) water soluble chloride concentration, $[Cl^-]_s$, increased with increasing temperature, and 4) chloride concentration profile for initially dry concrete specimens was higher than for the initially wet ones indicating pronounced capillary suction (sorption) occurred for the dry concrete specimens.

• Asian Journal of Atmospheric Environment
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• 제11권4호
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• pp.235-253
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• 2017

This study was conducted for analyzing the contribution factors on ozone concentrations and its long term trends in each major city and province in Korea through several statistical methods such as simple linear regression, generalized linear model, KZ-filer, correlation matrix, Kringing method, and cluster analysis. The overall ozone levels in South Korea have been consistently increasing over the past 10 years. The ozone concentrations in Seoul, the biggest city in Korea, are the lowest in all areas with the highest increasing ratio for $95^{th}%$ ozone. It is thought that the active photochemical reaction could affect the higher ozone concentration increase. On the other hand, the ozone concentrations in Jeju are the highest in Korea with the highest increasing ratio for $5^{th}%$, $33^{th}%$, and $50^{th}%$ ozone. It is also thought that the weak $NO_x$ titration could be the reason of higher ozone concentrations in Jeju. In case of Jeju, transport related factors is the major factor affecting the ozone trend. Thus, it is assumed that the variation of ozone trend of Asian region affecting the ozone trend in Jeju, where domestic ozone photochemical reaction is less active than urban area. It is thought that the photochemical reaction plays the role of increasing of ozone concentrations in the urban area, even though the LRT affected on the increase of ozone concentrations in non-urban area.

• 분석과학
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• 제8권3호
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• pp.305-311
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• 1995

Salicylic acid($C_6H_4(OH)COOH=H_2A$)와 전이금속인 Fe(III) 사이에 형성되는 착물의 안정도상수를 $20^{\circ}C$, 0.1M $KNO_3$ 수용액 중에서 자외-가시선 흡수광도법 및 pH 전위차적정법으로 측정하여 문헌값($logK_f=16.48$)과 비교하였다. $H_2A$의 $pK_{a1}$과 $pK_{a2}$는 $2.92{\pm}0.08$ 및 $12.90{\pm}0.13$이며, Fe(III)-$H_2A$의 1:1 착물의 $logK_f$는 $20^{\circ}C$에서 $11.88{\pm}0.12$였다.

• Journal of Dental Anesthesia and Pain Medicine
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• 제17권3호
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• pp.199-204
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• 2017

Background: Anxiety control remains an important concern in dental practice. We evaluated the incidence, nature, and sequelae of complications during and after minor oral surgeries performed under intravenous midazolam and fentanyl sedation using the titration technique. Method: The medical records of patients who had undergone minor oral surgeries under moderate intravenous midazolam and fentanyl sedation at our institution between January 1, 2015 and December 31, 2015 were retrospectively evaluated. Age, sex, body mass index, medical history, American Society of Anesthesiologists (ASA) classification, indications for sedation, amount of sedative used, surgical duration, and recovery time were evaluated for all patients. Results: In total, 107 patients aged 9-84 years were included. ASA class I and class II were observed for 56.1% and 43.9% patients, respectively. Complications associated with sedation occurred in 11 (10.2%) patients. There were no serious adverse events. Oxygen saturation reached 95% during the procedure in six patients; this was successfully managed by stimulating the patients to take a deep breath. Two patients exhibited deep sedation and one exhibited paradoxical excitement. After the procedure, one patient experienced nausea without vomiting and one exhibited a prolonged recovery time. The surgical procedures were completed in all patients. Obesity was found to be significantly associated with sedation-related complications. Conclusion: Our results suggest that complications associated with intravenous midazolam and fentanyl sedation using the titration technique for minor oral surgeries are mostly minor and can be successfully managed with no prolonged sequelae.

• Bulletin of the Korean Chemical Society
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• 제23권10호
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• pp.1413-1431
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• 2002

For the development of immunodetection method of 4,4'-dichlorodipheny-2,2,2-trichloroethane (p,p'-DDT), a persistent and broad toxic organochlorine insecticide, various DDT derivatives were synthesized and characterized for the use of immunogens and the coating ligands for the antibody evaluation. The appropriate lengths of linkers were introduced to investigate more efficient DDT derivatives. Among these hapten derivatives, 2,2-Bis(4-chlorophenyl)acetic acid (DDA), 5,5-Bis(4-chlorophenyl)-5-hydroxypentanoic acid (DDHP) and 5,5-Bis(4-chlorophenyl)-5-chloropentanoic acid (DDCP) were conjugated with keyhole limpet hemocyanin (KLH) for the use of immunogen to produce antibodies. 6,6-Bis(4-chlorophenyl)-6-hydroxyhexanoic acid (DDHH) and 3-[6,6-Bis(4-chlorophenyl)-6-hydroxyhexanoylamino]propanoic acid (DDHHAP) in addition to above hapten derivatives were conjugated to ovualbumin (OVA) and bovine serum albumin (BSA) for the use of coating ligands to measure the titration level of antibody and the displacement of free analytes. Three matching pairs of antibodies and coating ligands were selected for the simultaneous detection of p,p'-DDT and its related compounds of DDA and 2,2-bis(4-chlorophenyl)-1,1-dichloroethylene (p,p'-DDE) by investingating the displacement of free analytes in an indirect ELISA. These were PAb #1 and coating ligand DDCP-OVA, PAb #1 and DDHHAP-OVA, and PAb #3 and DDHHAP-OVA. The most useful immunoreaction for DDT analytes were obtained using PAb #3 and coating ligand DDHHAP-OVA showing 3.4 ng/mL of lower limit of detection. These results indicated that titration level and free analytes displacement were greatly influenced by hapten derivatized and carrier proteins conjugated.

• 대한화학회지
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• 제44권6호
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• pp.581-586
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• 2000

가압경수로형 사용후핵연료에 포함된 플루토늄을 분리하여 전기량 적정방벙으로 정량하였다. 플루토늄은 음이온 교환수지(AG MP-1)를 이용하여 분리하였으며 플루토늄의 정량은 조절전위전기량 적정방법을 이용하였다. 본 연구에서는 플루토늄 분리와 관련된 산화상태 조절, 분리 회수율 및 정량과 관련된 몇 가지 전기량 적정조건들에 대해 검토하였다. 실험결과 플루토늄은 산화상태를 조절하여 분리하는 것이 정량결과에 대한 정확도를 높였으며, 플루토늄의 전기량 적정결과에 미치는 몇 가지 금속이온들에 의한 영향은 나타나지 않았다. 플루토늄 표준용액을 이용하여 측정한 전기량 정량결과에 대한 정확도는 회수율로 나타냈을 경우 0.230∼3.02 mg 범위에서 99.36%이었다. 가압경수로형 사용후핵연료 용해용액들에 포함된 0.250∼0.450 mg의 플루토늄을 적정하여 얻은 전기량 정량결과에 대한 평균 정밀도(상대표준편차, RSD)는 0.38%이었다.

• Carbon letters
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• 제8권2호
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• pp.108-114
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• 2007

In this work, activated carbon (AC) after $HNO_3$ modification was used as the support during the production of supported $TiO_2$ to increase the high deposition efficiency and the photocatalytic activity. The results of $N_2$ adsorption showed that the BET surface area of samples decreased with an increasing of the concentration of $HNO_3$ due to the penetration of $TiO_2$. From XRD data, a single crystal structure of anatase peak was observed in diffraction patterns for the AC coated with titanium complexes. From the SEM results, almost all particles were aggregated with each other at the carbon surface and AC was covered with $TiO_2$ particles in all of the samples. The EDX spectra show the presence of C, O, Ti and other elements. It was also observed a decreasing of amount of C content with increasing Ti and O content from the EDX. The results of FT-IR revealed that the modified AC contained more surface oxygen bearing groups than that of the original AC. The effect of surface acidity and basity calculated from Boehm titration method was also evaluated from correlations as a function of NaOH, $NaHCO_3$, and $Na_2CO_3$ uptake. The surface modification of AC by $HNO_3$ leads to an increase in the catalytic efficiency of AC/$TiO_2$ catalysts, and the catalytic efficiency increases with increasing of $HNO_3$ concentration.

• Bulletin of the Korean Chemical Society
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• 제24권11호
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• pp.1605-1608
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• 2003

To development an immunodetection method for DDT, 1,1,1-trichloro-2,2-bis(4-chorophenyl)ethane (p,p'-DDT) and its metabolites (p,p'-DDA, p,p'-DDE, p,p'-DDD), five derivatives of DDT haptens have been synthesised and characterized as coating ligands for antibody evaluation. The appropriate lengths of linkers were introduced to investigate a matching pair of coating ligand and antibody. Among these hapten derivatives, 2,2-bis(4-chlorophenyl)acetic acid (DDA), 5,5-bis(4-chlorophenyl)-5-hydroxypentanoic acid (DDHP) and 5,5-bis(4-chlorophenyl)-5-chloropentanoic acid (DDCP) were conjugated with keyhole limpet hemocyanin (KLH) for its use as an immunogen. The bovine serum albumin (BSA) conjugates of these derivatives were prepared as a coating ligand for monoclonal antibody screening. Fifteen monoclonal antibody clones were screened using these probes. 6,6-Bis(4-chlorophenyl)-6-hydroxyhexanoic acid (DDHH) and 3-[6,6-Bis(4-chlorophenyl)-6-hydroxyhexanoylamino]propanoic acid (DDHHAP), in addition to the above hapten derivatives, were conjugated to ovualbumin (OVA) and bovine serum albumin (BSA) for their use as coating ligands to measure the titration level of the antibody and the displacement of free analytes. The indirect competitive ELISA results indicate that the titration level and free analyte displacement were greatly influenced by the DDT derivatives and carrier proteins used. Three matching pairs of monoclonal antibodies and coating ligands were selected for the DDT immunoassay: antibody clone 1A3 and coating ligand DDA-OVA, 1A1 and DDHHAP-BSA, and 1A4 and DDHP-OVA.