• 대한화장품학회지
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• 제14권1호
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• pp.1-15
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• 1988

A new method for liquid chromatography with post column reaction is suggested for the separation and quantification of tertiary amines. A mixture of triethanolamine and N-ethyl diethanolamine was separated by a strong cation exchange column, followed by spectrophtometric detection of the blue colors generated from the reaction of each amine with the Folin-Ciocalteau reagent. The tertiary amines were properly separated when an eluent of pH 9.5 containing 0.5M sodium nitrate was used. Under this condition, calibration curve of triethanolamine in 2-10mg/100ml concentration range was attained. Good results were obtained when cream and shampoo preparations containing known amount of triethanolamine were analysed according to this method. In case the sample did not contain any other interfering reducing substances, the amine was quantitatively determined by the simple reaction of the samples with Folin-Ciocalteau reagent, and the subsequent spectrophotometric measurement.

• 한국식품과학회지
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• 제24권5호
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• pp.497-503
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• 1992

영지 추출액의 항산화 활성을 thiocyanate method, TBA method, weighing method를 이용하여 검색한 결과 n-hexane 추출물, methanol 추출물에서 항산화활성이 나타났으며 그 중에서 n-hexane 추출물의 fraction V와 methanol 추출물의 methanol 불용성 fraction II에서 강한 활성을 나타내었다. 이들 항산화 활성을 나타내는 fraction 5와 fraction II를 rat의 간 균질액을 이용한 항산화 활성 검색에서 과산화 지질 생성억제를 TBA값으로 나타내어 inhibition ratio(I.R.)를 산출하였으며 그 결과 n-hexane 추출물의 fraction V는 l5%, methanol 추출물의 methanol 불용성 fraction II는 54.6%의 억제율을 나타내었다 이는 rat의 간 mitochondria에서 과산화지질 생성 억제율이 영지의 물 추출물은 16%, acetone 추출물은 23%인 것에 비하여 약간 높았으나, microsome에서 과산화지질 생성 억제율이 물 추출물은 44%, acetone 추출물은 75%인 것에 비하여 다소 낮은 활성을 보여주었다.

• Asian-Australasian Journal of Animal Sciences
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• 제17권11호
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• pp.1608-1614
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• 2004

This study was performed to evaluate the accuracy, validation and applicability of UV spectrophotometer (UV), Ion Chromatography (IC), and Detector tube (DT) methods for measuring ammonia (NH3) concentration in a swine confinement house and swine slurry storage tank. The mean values of $NH_{3}$ emitted from the house and slurry were 5.333 ppm and 42.192 ppm for the IC method; 4.13 ppm and 36.29 ppm for the Detector tube; and 5.417 ppm and 34.193 ppm for the UV method. The accuracy and the correlation of an ammonia level analyzed by the IC method compared to the UV method were 98% and 0.998($R^{2}$) in the swine confinement house and 94% and 0.997($R^{2}$) in the swine slurry storage tank. On the other hand, those of ammonia level measured by the Detector tube compared to the UV method were 77% and 0.957($R^{2}$) in the swine confinement house and 82% and 0.941($R^{2}$) in the swine slurry storage tank. This indicated that the accuracy and the correlation of the IC method compared to the UV method were higher than those of the Detector tube method compared to the UV method. Therefore, it was concluded that the IC method was more accurate in measuring ammonia concentration in a swine house and a swine slurry storage tank. The Detector tube method should not be applied to the swine slurry storage tank in which ammonia concentration is generally higher than 30 ppm because low accuracy is caused by a gross space between scales inscribed in the Detector tube.

• Earthquakes and Structures
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• 제12권3호
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• pp.271-284
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• 2017

This paper presents a multimodal adaptive nonlinear static method of analysis that, differently from the nonlinear static methods suggested in seismic codes, does not require the definition of the equivalent Single-Degree-Of-Freedom (SDOF) system to evaluate the seismic response of structures. First, the proposed method is formulated for the assessment of r.c. plane frames and then it is extended to 3D framed structures. Furthermore, the proposed nonlinear static approach is re-elaborated as a displacement-based design method that does not require the use of the behaviour factor and takes into account explicitly the plastic deformation capacity of the structure. Numerical applications to r.c. plane frames and to a 3D framed structure with inplan irregularity are carried out to illustrate the attractive features as well as the limitations of the proposed method. Furthermore, the numerical applications evidence the uncertainty about the suitability of the displacement demand prediction obtained by the nonlinear static methods commonly adopted.

• 대한의용생체공학회:의공학회지
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• 제17권4호
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• pp.469-478
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• 1996

In the conventional digital ultrasound scanner, the reflected signal is sampled either in polar coordinates of R-$\theta$ method, or in Cartesian coordinates of uniform ladder algorithm (ULA). The R-$\theta$ scan method necessitates a coordinate transform process which makes hardware complex in comparison with ULA scan mrthoA In spite of this complexity, R-$\theta$ method has a good resolution in ultrasonographic (US) image, since scan direction of the US imaging is a radial direction. In this paper, a new digital scan converter is proposed, which is named the radius uniform ladder algorithm (RULA). The RULA has the rome scan direction as the US scanning in the radial direction and as the display space in the $\theta$ direction. In tllis new approach, sampled points we uniformly distributed in each horizontal line i.n well as in each radial ray so that the data are displayed in the Cartesian coordinates by the 1-D interpolation process. The propped algorithm has an uniform resolution in the periphery and the center field in comparison with equi-angle ULA and equi-interval ULA. To extend the scan angle, concentric square raster sampling (CSRS) is adopted with reduction of discontinuities on the junctions between horizontal scan and vertical scan. The discontinuities are reduced by using the hmction filtering along the $\theta$ direction.

• 대한환경공학회지
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• 제36권11호
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• pp.764-770
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• 2014

본 연구는 electron impact-gas chromatography/mass spectrometer (EI-GC/MS)를 이용하여 N-nitrosamines 분석하는 방법의 분리성, 정성 및 정량적 유효성을 평가하였다. 극미량의 검출을 위해 시료전처리는 자동고상추출과 질소농축과정을 거쳐 수행하였다. 표준시료를 전처리 없이 EI-GC/MS (SIM)와 EI-GC/MS/MS (MRM)를 이용하여 직접 분석한 결과, 두 방법 모두 유사한 감응도를 보였다. 반면, 전처리한 표준시료를 EI-GC/MS로 분석한 경우 불순물 피크에 의한 간섭영향에 의해 낮은 ng/L 수준의 정량은 어려운 것으로 나타났다. 8종의 N-nitrosamines에 대한 EI-GC/MS/MS 분석결과, 방법검출한계 및 정량한계는 각각 0.76~2.09 ng/L, 2.41~6.65 ng/L 수준으로 기존 분석방법에 비하여 낮게 나타났다. 첨가농도 10, 20, 100 ng/L에 대한 실험에서 정밀도(1.2~13.6%)와 정확도(80.4~121.8%) 모두 만족하였으며, 검량선의 직선성에 대한 결정계수($R^2$)도 0.999 이상이었다. 환경시료에 대한 대체표준물질(NDPA-$d_{14}$)의 회수율도 86.2~122.3%을 나타내어, 본 연구에서 평가된 방법으로 N-nitrosamines의 정밀분석이 가능함을 검증하였다.

• 정보보호학회논문지
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• 제8권2호
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• pp.27-36
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• 1998

최근들어 타원곡선 암호법(ECC)이 RSA암호법을 대체할 것으로 기대되면서ECC의 연산속도를 결정하는 중요한 요소인 유한체의 연산 속도에 관심이 고조되고 있다. 본 논문에서는 Modified 최적 정규 기저의 성질 규명과 GF(q)(q=2$^{k}$ , k=8또는 16)위에서 GF(q$^{m}$ )(m: 홀수)의 Mofdified trinomial 기가 존재하는 m들을 제시하고, GF(r$^{n}$ )위에서 GF(r$^{nm}$ )dml Modified 최적 정규기저와 Modified trinomial 기저를 이용한 연산의 회수와 각 기저를 이용한 연산의 회수와 각 기저를 이용한 유한체 GF(q$^{m}$ )의 연산을 S/W화한 결과를 비교 하였다.

• Nonlinear Functional Analysis and Applications
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• 제26권5호
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• pp.1035-1044
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• 2021

Existence and uniqueness results for solutions of system of Riemann-Liouville (R-L) fractional differential equations with initial time difference are obtained. Monotone technique is developed to obtain existence and uniqueness of solutions of system of R-L fractional differential equations with initial time difference.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제38권5호
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• pp.276-283
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• 2012

Objectives: Curettage and enucleation are two of the most common procedures performed in oral and maxillofacial surgery units. To access a cystic lesion, the buccal cortical plate is removed. The no reposition (NR) group underwent surgery without repositioning the buccal cortical plate. The reposition (R) group underwent surgery with a repositioning of the buccal cortical plate. This study compared the two surgical procedures in terms of bone healing and complications. Materials and Methods: Patients who underwent curettage and enucleation surgery were enrolled in this study. Panoramic radiographs of the patients in both the NR group (n=26) and R group (n=34) were taken at the baseline and at 6, 12 and 24 months after surgery. The radiolucent area was calculated to evaluate bony healing in each radiograph. The complications were analyzed through a review of the medical records. Results: The correlation between bony healing and surgical approach was not significant in the 6th, 12th, and 24th month (P<0.05). The complication rate was not associated with gender, graft material, bone graft and drain insertion (P<0.05). On the other hand, the R group had a higher complication rate (35.3%) than the NR group (0%). The difference in the mean lesion size between the NR group ($37,024{\pm}3,617$ pixel) and R group ($92,863{\pm}15,931$ pixel) was significant (independent t test, P=0.004). Conclusion: Although the reposition method is chosen when the lesion size is large, it is associated with more complications. Indeed, infection, discomfort and recurrence of the lesion were the most common complications in the R group. Furthermore, the R method does not have a strong point in terms of bone healing compared to the NR method. Therefore, the R method cannot be considered an ideal approach and should be used in limited cases.

• 대한임상검사과학회지
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• 제37권2호
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• pp.88-95
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• 2005

Even though the echocardiograph has been recognized as the method of choice among various diagnostic tools to detect congestive heart failure (CHF), there were some limitations in relation to the consumption of time, labor and process. We analyzed results of N-terminal probrain-type natriuretic peptide (NT-proBNP) and various parameters of the echocardiographic findings to clarify the diagnostic usefulness of NT-proBNP in detecting patients with CHF. We analyzed the sera from total of 242 cases from in-patients and out-patients, which were requested from the cardiovascular section of department of Internal Medicine at Chungnam National University Hospital from March 2003 to May 2004. The procedures were performed in order as shown below; sampling, NT-proBNP analysis, data acquisition and data analysis. All data including personal information and echocardiographic findings ware acquired by medical record review. When classifying the study population into six groups according to the degree of left ventricular ejection fraction (LVEF), the serum level of NT-proBNP was higher in the group with 51-60% of LVEF (P=0.023). There were low correlation between the serum level of NT-proBNP and various parameters of the echocardiographic findings with LVESD (r=0.1513), LVEDD (r=0.0831), LVEF (r=0.2035), IVST (r=0.03) and LVPWT (r=0.0728), respectively. When comparing NT-proBNP with atrial and/or ventricular enlargement, the patient group with both left atrial and left ventricular enlargement (p=0.186) or only left atrial (p=0.105) or only left ventricular enlargement (p=0.256) showed higher level of NT-proBNP without statistical significance than patient group with no enlargement. Searching the optimal cutoff of the serum level of NT-proBNP, the sensitivity (98.9%) and the specificity (100%) was highest at the cutoff of 300 pg/mL than any other cutoffs. These findings suggested that the analysis of NT-proBNP in serum might detect the patients with CHF earlier than with the echocardiograph, especially in patients with asymptomatic or mild symptomatic CHF. In conclusion, NT-proBNP test was proved to be clinically useful to diagnose CHF patients.