• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.1-5
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• 2015

This study aimed to simultaneously determine various carotenoids from different colored paprika using an ultra performance liquid chromatograph (UPLC) equipped with a HSS T3 column. Analysis was performed at 450 nm using gradient conditions with acetonitrile/methanol/methylene chloride (65/25/10) and distilled water. We improved the peak resolution and performed carotenoid analysis within 30 min. We qualitatively analyzed 11 carotenoids (neoxanthin, capsorubin, violaxanthin, capsanthin, zeaxanthin, lutein, ${\alpha}$-cryptoxanthin, ${\beta}$-cryptoxanthin, lycopene, ${\alpha}$-carotene, and ${\beta}$-carotene). For the validation of UPLC methods, we validated the precision and accuracy of capsanthin. Capsanthin showed good linearity ($R^2$=0.9998) in the concentration range of $1-200{\mu}g/mL$ with 2.4 and $7.2{\mu}g/mL$ of limit of detection (LOD) and limit of quantification (LOQ), respectively. The relative standard deviation (RSD) for intra- and inter-day precision was less than 3.83%. Recovery was in the range of 91.86-99.87%. We quantitatively analyzed carotenoid contents from 8 different colored paprika (red, orange, yellow, and green). The most abundant carotenoids were capsanthin in red paprika, and zeaxanthin in orange, yellow, and green paprika.

• Korean Journal of Food Science and Technology
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• v.50 no.4
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• pp.377-382
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• 2018

An HPLC method was developed to quantitate a marker, oxyresveratrol (ORT), for the standardization of mulberry branch extracts (MBE) as a functional ingredient. HPLC was performed on a $C_{18}$ column with a gradient elution using 0.05% $H_3PO_4$ and acetonitrile at a flow rate of 0.8 mL/min, and detected at 320 nm. The HPLC method was validated according to Korea Food and Drug Administration (KFDA) guideline of analytical procedures with respect to specificity, linearity, accuracy and precision. Calibration curve of ORT showed high linearity ($R^2=1$), and limits of detection and quantification were 0.3 and $1.0{\mu}g/mL$, respectively. Relative standard deviation values from intra-and inter-day precision were less than 3.52 and 4.70%, respectively. Recovery rate ranged from 97.64% to 103.69%, and ORT content in MBE was approximately 3.78%. These results suggest that the HPLC method developed for the analysis of ORT in MBE is simple, efficient, and could contribute to the quality control of MBE.

• Analytical Science and Technology
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• v.24 no.6
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• pp.421-428
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• 2011

In this study, headspace disk type monolithic material sorptive extraction (HS-MMSE) was developed, validated and applied to the analysis of volatile aroma compounds from vanilla perfume by gas chromatography -mass spectrometry (GC/MS). HS-MMSE uses monolithic material (MonoTrap) based on silica bonded with octadecyl silane (ODS) and activated carbon as a sorbent. Aroma compounds was adsorbed onto the MonoTrap in headspace and extracted by only 100 ${\mu}L$ of solvent. Total 12 volatile compounds from vanilla perfume were successfully analyzed using HS-MMSE. The influence of extractive parameters was investigated and optimized, using benzyl acetate, linalyl acetate, vanillin, ethyl vanillin as target compounds. Under the optimum condition, the limit of detection (S/N = 3) and the limit of quantification (S/N = 10) of proposed method for the target compounds were obtained within the range of 8.35~13.76 ng and 27.82~45.88 ng, respectively. The method showed good linearity with correlation coefficient more than 0.9888, satisfactory recovery and reproducibility. These results showed that HS-MMSE using disk type MonoTrap is a new promising technique for the analysis of volatile aroma compounds from vanilla perfume.

• Analytical Science and Technology
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• v.25 no.6
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• pp.476-482
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• 2012

Asian dust particles are known to have sizes ranging from a few nanometers up to about a few micrometers. The environmental and health effects depend on the size of the dust particles. The smaller, the farther they are transported, and the deeper they penetrate into the human respiratory system. Sedimentation field-flow fractionation (SdFFF) provides separation of nano to microparticles using a combination of centrifugal force and parabolic laminar flow in a channel. In this study, the steric mode of SdFFF (Sd/StFFF) was tested for size-based separation and characterization of Asian dust particles. Various SdFFF experimental parameters including flow rate, stop-flow time and field strength of the centrifugal field were optimized for the size analysis of Asian dust. The Sd/StFFF calibration curve showed a good linearity with $R^2$ value of 0.9983, and results showed an excellent capability of Sd/StFFF for a size-based separation of micron-sized particles.The optical microscopy (OM) was also used to study the size and the shape of the dust particles. The size distributions of the samples collected during a thick dust period were shifted towards larger sizes than those of the samples collected during thin dust periods. It was also observed that size distribution of the sample collected during dry period shifts further towards larger sizes than that of the samples collected during raining period, suggesting the sizes of the dust particle decrease during raining periods as the components adsorbed on the surface of the dust particles were removed by the rain water. Results show Sd/StFFFis a useful tool for size characterization of environmental particles such as the Asian dust.

• Analytical Science and Technology
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• v.25 no.6
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• pp.460-466
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• 2012

An environmentally friendly, so-called green, high performance liquid chromatography method was developed and validated for the determination of trans, trans-muconic acid (t,t-MA) in human urine as a biomarker of benzene exposure. After urinary t,t-MA was extracted and enriched using solid-phase extraction, a MF-Ph1 SG80 ($150mm{\times}2.0mm$ I.D., 5 ${\mu}m$) column with a mobile phase of 10 mM $KH_2PO_4$ containing 0.1% $H_3PO_4$ was used for isocratic separation of t,t-MA with UV detection at 259 nm. The calibration curve was constructed in the range of 0.1-5.0 mg/L with good linearity ($r^2$=0.9992). The intra-day and inter-day precision (as RSD) were 0.9-8.5% and 3.1-4.5%, respectively. The average recovery ranged from 97.5% to 101.7%. The green sample preparation and separation with no organic solvents were successfully achieved. The validated method would be suitable for the routine biological monitoring of benzene exposure in the occupational settings.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.215-227
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• 2002

The purpose of this study was to investigate propulsive time and kinematic variables on the three different kinds of the basketball wheelchairs in each play position for eight abled basketball wheelchair players. Kinematic data were collected by a video camera for two-dimensional analysis. The wheelchairs for the guard position showed the fastest in total propulsive time. The wheelchairs for the center position revealed the slowest in the phase of the change of the direction. The wheelchair for the guard position which shows fast movement velocity demonstrated closer hand contact with TDC(Top Dead Center). The wheelchair for the center position revealed the largest extension of the elbow and flexion of the trunk at handrim contact. The wheelchair for the guard position which has the lowest seat height presented larger elbow angle and trunk angle. The wheelchair for the guard position produced more fast trunk angular velocity than the wheelchair for other positions.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.6
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• pp.374-378
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• 2008

For the standard method of collecting the run-off, it is consumed the high cost and much effort to install and to manage this instrument. Because the all the soil and water from reservoir tank must be eliminate after their measurement of amount of soil loss and run-off and installed the reservoir tank at regular size in the experimental field. Therefore, objective of this study was to compare its efficacy between the standard method and a flow rotate divider for ontinuously collecting and measuring the soil loss and run-off in order to conveniently conduct the field experiment of the lysimeters. For collecting the sampling of soil loss and run-off from agricultural land with invariable ratio, a flow rotate divider was consisted with a 8 blades of round plate sloped in order to collect the invariable ratio of soil and water at lowest part from round plate by the law of gravity. For comparing its accuracy in the batch scale experiment, it shown that there was significantly a positive linear corelation ($r=0.997^{***}$) between flowing and sampling amounts with adjusting the range from 1 to $10L\;min^{-1}$ with flowing rate. In collecting ratio in the field experiment, it observed that the more its accuracy had, the more soil loss and run-off.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.976-980
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• 2005

자연하천과 같은 사행수로에서 발생하는 이차류는 흐름 분포를 왜곡시킴으로써, 유사이동, 하상과 제방침식, 하천의 지형변형 등에 매우 큰 영향을 미치게 된다. 또한, 이차류는 주 흐름방향에 수직으로 발생하기 때문에 자연하천에 유입된 오염물의 횡방향 혼합에도 지대한 역할을 한다. 따라서, 본 연구에서는 사행수로에서 이차류의 특성을 정량적으로 분석하고자 중심각이 $120^{\circ}$인 두 개의 만곡부로 이루어진 사행수로에서 실험을 수행하였다. 실험수로는 직사각형 단면과 자연형 단면 두 가지 형태로 제작하였으며, 자연형 단면 하상은 베타함수를 이용하여 제작하였다. 이차류의 정확한 측정을 위해 3차원 유속측정 장치인 micro-ADV를 이용하였다. 실험조건으로는 직사각형 단면과 자연형 단면에서 평균수심과 유량을 달리하여 실험을 총 12회 수행하였다. 실험결과, 직사각형 단면수로에서의 주 흐름의 최대유속선은 수로의 가장 짧은 경로를 따라 발생하였는데, 이는 Shiono와 Muto (1998)의 결과와 일치한다. 자연형 단면 수로에서의 주 흐름은 직사각형 단면 수로에서의 주 흐름 거동과 비슷한 양상을 보였다. 이것은 실제 자연하천 만곡부에서의 주흐름 거동(최대유속선이 최심선을 따라 발생)과는 상이한 결과였다. 그 첫째 원인은 실험수로의 조도가 일반적인 실제하천의 조도를 상사법칙에 맞게 계산한 값보다 작았기 때문이다. 그리고 두 번째 원인은 실험수로의 하폭대 수심비율은 실제하천의 하폭대 수심비율보다 컸기 때문인 것으로 사료된다. 이차류의 정량적인 분석을 위해 각 측정지점별로 횡방향, 수심방향 유속을 그려본 결과, 직사각형 단면에서는 하나의 셀이 존재하는 반면에 자연형 단면에서는 셀이 두개 존재함을 알 수 있었다. 이는 자연하천에서도 발견되는 현상이다. 실제 자연하천에서는 주 셀이 바깥제방 셀보다 큰 형태를 보이지만, 실험수의에서의 셀의 형태는 주 셀보다 바깥제방 셀이 더 크게 발생하는 것으로 밝혀졌다. 이는 앞서 언급한 바와 같이 조도가 작음으로 인한 것으로 판단된다. 이차류 강도를 계산한 결과, 직사각형 단면 수로의 최대값은 두 번째 만곡 유입부지점(U2)에서 가장 크게 나타났으며. 자연형 단면 수로에서 최대값은 두 번째 만곡을 조금 지난 (U4)지점에서 가장 크게 나타났다. 자연형 단면에서는 하폭 대 수심비가 커질수록 이차류강도가 크게 나왔으나, 직사각형 단면에서는 반대로 나왔다. 그리고, 자연형 단면의 이차류 강도는 직사각형 단면보다 크게 나타났다. 특히, 직사각형 단면의 이차류강도는 첫 번째 만곡부분보다 두 번째 만곡부분이 더 크게 나타나는 현상만 보였지만, 자연형 단면의 이차류 강도는 앞서 언급한 특징 외에 만곡부에서 증가하고, 직선부에서 감소하는 주기적인 형태를 보였다.

• Journal of Applied Biological Chemistry
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• v.53 no.1
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• pp.25-30
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• 2010

This paper describes a simultaneous method for the determination of two aminoglycosides (neomycin and gentamicin) using solid phase extraction followed by liquid chromatograph-mass spectrometry. The extract was applied to an WCX and HLB solid phase extraction cartridge. The cartridges were washed with water and methanol, and analytes were eluted with TCA buffer-acetonitrile mixture. The aminoglycosides were separated by ion-pairing reversed phase mode prior to ESI-LC/MS. Under the conditions applied neomycin was almost separated from all the gentamicin compounds. No interfering peaks from endogenous compounds of matrix were noted at the elution position of the analytes. Recoveries of neomycin fortified at levels of 0.25, 0.5, 1.0 and 2.0 mg/kg seafood samples ranged from 92 to 115%. Recoveries of gentamycin fortified at levels of 0.05, 0.1, 0.2, 0.4 mg/kg seafood samples ranged from 99 to 116%. Method detection limits in four seafood sample matrices were between 0.002 and 0.033 mg/kg.

• Magazine of the Korean Society of Agricultural Engineers
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• v.18 no.1
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• pp.4011-4020
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• 1976

본논문은 북해도대학심사학위논문으로 총면수 143면인 영문으로 되어 있고 도 48, 표 7, 문묵 66부도, 부표 20면이있음. Plow는 옛부터 발달한 농구이기 때문에 많은 연구가 행하여졌지만 복잡한 물리성을 가준 토양을 대상으로 하는 기계이기 때문에 미해결의 문제도 적지않다. 이견인저항에 대하여 토양의 종류 및 조건을 변경하면서 실제의 포장에서 조직적으로 행한 실험은 극히 적고, 하물며 우리나라의 쟁기에 관한 연구는 거의없다. 본논문은 쟁기의 특징을 구명하고, 그의 개량, 발달에 기여하기 위한 기기자료를 획득코저 실시한 것이다. 1. 쟁기와 플라우의 구조 및 그의 차이 특징을 명백히하고 이체에 걸리는 각종의 저항의 내용 또는 그 비율등에 대하여 과거의 연구성과를 소개하였다. 2. 발달사 ; 플라우는 B.C. 2000년경에 녹각, 목지의 인력용의 경운용구에서 발달하고, 동양이도 기원은 대체로 같고 발달과정이 다를 뿐이다. 쟁기는 양자강연안에 기원을 가진 지나이가 신라와 백제에 도입되여 차차 발달하고, 지역적인 특징을 가지게 되었다. 3. 본장은 쟁기의 견인력에 관한 이론적해석을하고, 쟁기의 진행에 의해 층상으로 전단되는 전단저항을 구하고 쟁기의 표면 및 지측판과 토양과의 마찰력, 그리고 토양의 이동의 관성력을 쟁기의 견인저항에 관련되는 주요한 "힘"으로 생각하고 진행방면, 수직방면의 힘의 성분의 평형을 고려하여 식 10. 12를 유도 하였다. 4. 본장에서는 실험계획, 방법 공시기, 공시포장등을 기록하고, 축력용의 쟁기와 플라우를 사용하여 전지 4종 답 2종의 포장에서 실험하는데 견인력계와 자동경심측정기를 사용하였다. 5. 실험결과 및 고찰; 경심과 견인저항 Dp와의 관계는 식 10. 12와 갈이 표시되고, 실제의 제치를 대입하여 이론식을 유도하였으니 직선에 가까운 관계가 있고, 실험결과는 조금 곡선에 가까워졌다. 그리고, 토양의 물리성이 견인력Dp에의 영향을 세밀히 검토하였다. 쟁기의 견인비저항에 있어서도 식 12에서 {{{{K=AT+ { B} over {T } +C}}}}로 표시할수 있기 때문에 최소치를 표시하는 경심이 존재하고 이값은 쟁기나 플라우폭의{{{{ { 1} over {2 } }}}} 즉 10m정도이고 쟁기는 비저항이 0.llkg/$\textrm{cm}^2$에서 0.39kg/$\textrm{cm}^2$이였다. 그러나 이 비저항도 토양의 물리성이 많은 영향을 미치고 있다. 6. 요약 및 결론 ; 이상의 장에서 검토 고찰한 결과만을 기재하고 플라우는 쟁기에 비해 견인저항 및 비저항이 논에서나 밭에서 대로 나타난 것이 특이하다. 이상의 내용을 지면관계로 3회에 거쳐 요약 발표합니다.