• 한국정밀공학회지
• /
• 제32권5호
• /
• pp.415-422
• /
• 2015

Ballscrews are important motion transfer and positioning units of industrial machinery and precision machines. Positioning accuracy of the feed drive system depends upon axial stiffness of ballscrew systems. As the nut stiffness depends upon preload and operating conditions, analytical modeling of the stiffness is performed through the contact and body deformation analysis. For accurate contact analysis, the contact angle variation between balls and grooves is incorporated in the developed model. To verify the developed mathematical stiffness model, experiments are conducted on the test-rig. Through the uncertainty analysis according to GUM (Guide to the expression of Uncertainty in Measurement), it is confirmed that the formulated stiffness model has over 85% estimation accuracy. After constructing the ballscrew DB, a quick turnaround system for the nut stiffness estimation has been developed in this research.

• The Plant Pathology Journal
• /
• 제32권3호
• /
• pp.209-215
• /
• 2016

In this study, the treatment of pistachio nuts by Bacillus subtilis UTBSP1, a promising isolate to degrade aflatoxin B1 (AFB1), caused to reduce the growth of Aspergillus flavus R5 and AFB1 content on pistachio nuts. Fluorescence probes revealed that the cell free supernatant fluid from UTBSP1 affects spore viability considerably. Using high-performance liquid chromatographic (HPLC) method, 10 fractions were separated and collected from methanol extract of cell free supernatant fluid. Two fractions showed inhibition zones against A. flavus. Mass spectrometric analysis of the both antifungal fractions revealed a high similarity between these anti-A. flavus compounds and cyclic-lipopeptides of surfactin, and fengycin families. Coproduction of surfactin and fengycin acted in a synergistic manner and consequently caused a strong antifungal activity against A. flavus R5. There was a positive significant correlation between the reduction of A. flavus growth and the reduction of AFB1 contamination on pistachio nut by UTBSP1. The results indicated that fengycin and surfactin-producing B. subtilis UTBSP1 can potentially reduce A. flavus growth and AFB1 content in pistachio nut.

• Mass Spectrometry Letters
• /
• 제5권4호
• /
• pp.115-119
• /
• 2014

The Brazil nut (Bertholletia excelsa - Lecythidaceae) is considered a product with high economic value, being a food widely appreciated for its nutritional qualities. Although previous studies have reported the biochemical composition of Brazil nut oil, the knowledge regarding the phospholipid composition exhibits a disagreement: the composition of fatty acids present in the structures of phospholipids is reported as being different from the composition of the free fatty acids present in the oil. In this work, solid phase extraction (SPE) was employed to provide a fast extraction of the phospholipids from Brazil nuts, in order to compare the phospholipid profile of the in nature nuts and their fatty acids precursor present in the oil. The major phospholipids were characterized by mass spectrometry approach. Their fragmentation pattern through direct infusion electrospray ionization ion-trap tandem mass spectrometry ($ESI-IT-MS^2$) proved to be useful to unequivocal characterization of these substances. High resolution (HR) experiments through ESI using a quadruple time of flight mass spectrometry (QTOF) system were performed to reinforce the identifications.

• 한국식품과학회지
• /
• 제13권1호
• /
• pp.1-5
• /
• 1981

한국산 개암종실의 유리 및 전(全)아미노산의 종류 및 함량을 아미노산 자동분석기 (Technicon PNC-1 type)에 의해서 정량한 결과 유리아미노산의 전체량은 4.14mg/g이고 전(全)아미노산의 총함량은 180.64 mg/g이며 유리 아미노산 중 아르기닌의 함량이 가장 많고 글루탐산, 프롤린, 알라닌 및 발린의 순이었고 전(全)아미노산의 경우 역시 아르기닌의 함량이 가장 높고 그 다음이 글루탐산, 프롤린, 로이신 및 아스파르트산으로서 개암중에는 영양학적으로 중요한 필수아미노산을 모두 함유하고 있어서 영양상 뿐만 아니라 풍미도 나쁘지 않다고 생각된다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.911-915
• /
• 2014

Pyrotechnic devices are widely used for space appendages. However, a cube satellite requirements do not permit the use of explosive pyrotechnic device. A nichrome burn wire release has typically been used for holding and release of deployable appendages of the cube satellite due to its simplicity and low cost. However, relatively low mechanical constraint force and system complexity for application of multi-deployable systems are disadvantages of the conventional mechanism. To overcome these drawbacks, we have developed a segmented nut type holding and release mechanism based on the nichrome burn wire release. The great advantages of the mechanism are much lower shock level and larger constraint force than the conventional mechanism using pyro. Flight model for on-orbit verification was developed and verified through release function test, vibration test and thermal vacuum test.

• 사상체질의학회지
• /
• 제14권3호
• /
• pp.174-180
• /
• 2002

The jaundice means hyperbilirubinemia that it happens bilirubin is contained for much in the blood for the disorder of formation and evaluation about bilirubin. The dry nut is one of the representative medicine which made use of Tae eum in bokchang bujong byung(태음인의 복창부종병) and that is marked use of removing the obstruction of tae eum in, by removing the damping heat(습열) and that is to depend on not the circle of medicine but the food The diet cure of a dry nut might be profound in meaning because the jaundice, the disorder of liver and gall, can be considered in relation to Tae eum in bokchang bujong byung(태음인의 복창부종병) I make a report in the basis of the reliably remedial value about application of a diet cure that a dry not is used to the patient coming to my hospital for the jaundice of ruing his health in eating and drinking

• Carbon letters
• /
• 제9권3호
• /
• pp.188-194
• /
• 2008

Porous carbon materials synthesized from various plant derived precursors i.e. seeds of [Castor (Ricinus communis), Soap nut (Sapindus sp.), Cashew-nut (Semecarpus anacardium), Jack fruit (Artocarpus heterophyllus), Safflower (Carthamus tinctorius), Ambadi (Crotolaria juncea), Neem (Azadirachta indica), Bitter Almond (Prunus amygdalus), Sesamum (Sisamum indicum), Date-palm (Phoenix dactylifera),Canola (Brassica napus), Sunflower (Helianthus annulus)] and fibrous materials from [Corn stem- (Zea mays), Rice straw (Oryza sativa), Bamboo (Bombax bambusa) and Coconut fibers (Cocos nucifera)] were screened to make supercapacitor in 5M KOH solution. Carbon material obtained from Jack fruit seeds (92.0 F/g), Rice straw (83.0 F/g), Soap nut seeds (54.0 F/g), Castor seeds (44.34 F/g) and Bamboo (40.0 F/g) gave high capacitance value as compared to others. The magnitude of capacitance value was found to be inversely proportional to the scan rate of measurement. It is suggested that carbon material should possess large surface area and small pore size to get better value of capacitor. Moreover, the structure of carbon materials should be such that majority of pores are in the plane parallel to the plane of electrode and surface is fluffy like cotton ball.

• Nuclear Engineering and Technology
• /
• 제55권8호
• /
• pp.2905-2918
• /
• 2023

The valve assembly used in nuclear power plants is important safety-related equipment. In the new standard, the physical attributes are measured using a valve diagnosis test, which is used in the expansion to other non-tested valves using a quantitative test-basis methodology. With a motor-operated actuator, the state of stem's lubrication is related to physical attributes such as the stem factor and the friction coefficient. This study analyzed the numerical transient of fluid and solid lubrication with a squeeze film effect due to the loading rate on the stem and the stem nut using the experimental data. The differential equation that governs the motion mechanism of the stem and stem nut is established and analyzed. The flow rate, the fluid and the solid contact forces are calculated with the friction coefficient. Finally, we found that a change in the friction coefficient results from a change of the shear force in the solid contact mode during the interchange process between the solid contact mode and the fluid contact mode. The qualitative understanding of the squeeze film effect is expanded quantitatively for forces, thread surface distance, velocity, and acceleration, with consideration of the metal solid contact and fluid contact.

• Weed & Turfgrass Science
• /
• 제2권1호
• /
• pp.30-37
• /
• 2013

본 연구의 목적은 국내의 대표적인 침엽수인 소나무, 잣나무, 낙엽송, 분비나무로부터 추출된 정유의 제초활성을 이해하는데 있었다. 소나무, 잣나무, 낙엽송, 분비나무 정유의 기내 종자발아 제초활성 검정 결과, 유채에 대한 $GR_{50}$ 값은 각각 0, 4,766, 1,865, $5,934{\mu}g\;ml^{-1}$으로 소나무를 제외하고는 제초활성을 나타내었다. 온실조건에서 소나무, 잣나무, 낙엽송, 분비나무 정유 10%를 5종의 화본과 잡초와 5종의 광엽잡초에 처리한 결과 도꼬마리를 제외하고는 24시간 내에 완전 고사되었으며, 처리 식물의 부위는 타는 듯한 화염상 증상을 나타내었고, 처리 3일 이후에는 신초가 재생하여 4종 식물 정유는 속효성, 비선택성, 비이행성 특성을 나타내었다. 소나무, 잣나무, 낙엽송, 분비나무의 정유를 GC-MS로 분석한 결과 각각 16종, 25종, 25종, 16종의 유기화합물이 검출되었으며, 이들 정유에는 탄화수소, 알코올, 케톤, 에스테르가 공통적으로 함유되어 있었다. 그리고 정유 4종의 주 화합물은 3-carene, bornyl acetate, camphene, limonene, ${\alpha}$-pinene, ${\beta}$-pinene, ${\beta}$-phellandrene 이었다.

• 한국식품영양과학회지
• /
• 제44권2호
• /
• pp.165-172
• /
• 2015

정향, 감, 오배자, 황벽, 치자, 홍화황 및 아나토와 같은 천연 식물로부터 얻어진 색소 추출물의 항산화 및 항비만 활성을 비교 분석하였다. 총 페놀 함량은 오배자 추출물에서 2,441.45 mg/kg으로 가장 높았고, 다음으로 정향 추출물에서 1,346.48 mg/kg으로 높았다. DPPH와 ABTS 라디칼 소거 활성 및 환원력을 이용한 항산화 활성은 오배자 추출물에서 가장 높았다. ${\alpha}$-Glucosidase에 대한 저해 활성은 감 추출물에서 ($IC_{50}=22.83{\mu}g/mL$) 가장 높았고, 다음으로 오배자 추출물에서 높았다. ${\alpha}$-Amylase 및 lipase에 대한 저해 활성 역시 감 추출물 처리 시 각각 49.45% 및 61.01%로 높은 활성을 보였다. $20{\mu}g/mL$ 농도로 처리 시 3T3-L1 세포 내 지방 축적율은 감, 정향 및 아나토 추출물 처리군에서 각각 81.54%, 83.36% 및 85.70%로 대조군에 비해 유의적으로 낮았다. 3T3-L1 세포 내 triglyceride 함량은 정향 추출물 처리군이 66.11%로 가장 낮았고 다음으로 감 추출물 처리 군에서 88.88%로 유의적으로 낮았다. 천연식물류로부터 추출한 색소 원료 중 오배자 추출물이 높은 항산화 활성을 나타내었으며, 감 추출물은 소화효소 저해 활성과 3T3-L1 세포 내의 지방 축적 억제 효과를 가짐으로써 항비만 활성을 나타내는 것으로 판단된다.