• 한국식품영양과학회지
• /
• 제27권1호
• /
• pp.80-86
• /
• 1998

This work was designed to determine the optimum roasting conditions with application of a pressure roaster for improving the roasting process of the Polygonatum sibiricum tea which has been roasting with a traditional method. Soluble solid content of the Polygonatum cibiricum tea was 63.16% in the tea roasted at 0.85kgf/$\textrm{cm}^2$(roasting pressure) and 13.9min(roasting time) which were maximum point by the ridge analysis. The optimum conditions predicted for each corresponding sensory properties of the Polygonatum cibirium tea were 0.87kgf/$\textrm{cm}^2$ and 9.2min in color, 0.89kgf/$\textrm{cm}^2$ and 9.7min in sweet 0.72kgf/$\textrm{cm}^2$ and 5.4min in burnt flavor, 0.89kgf/$\textrm{cm}^2$ and 9.9min in appetizing flavor, 0.87kgf/$\textrm{cm}^2$ and 9.3min in aftertaste, 0.89kgf/$\textrm{cm}^2$ and 10.0min in aroma, and 0.88kgf/$\textrm{cm}^2$ and 9.6min in overall acceptability of the tea. The optimum conditions based on the soluble solid content and sensory properties of the Polygonatum cibiricum tea, were 0.83~0.88kgf/$\textrm{cm}^2$ and 9.7~10.4min.

• 대한안전경영과학회지
• /
• 제7권4호
• /
• pp.61-71
• /
• 2005

Many researches have been focused on the analysis of industry disasters in order to reduce them. As a similar endeavor, this paper provides a propensity analysis of injured people from various industries using classification and regression tree(CART), a data mining algorithm. The sample for this work was chosen from 25,157data related to various industries during one year ( $2003.2\sim2004.1$ ) at Kangwon-Do in Korea. For the purpose of this paper, eight independent variables (injured date, injured time, injured month, type of Injured person, continuous service period, sex, company size, age)are taken from injured person group. According to the analysis result, it is found that five out of the eight factors that are predicted as significant have salient effects. Factors of season, time/hour, day of the week, or month which disasters happened do not show any significant effect. This paper provides common features of injured people. The provided analysis result will be helpful as a starting point for root cause analysis and reduction of industry disasters and also for development of a guideline of safety management.

• 한국공간구조학회논문집
• /
• 제18권3호
• /
• pp.83-91
• /
• 2018

In this study, we investigated the dynamic stability of the system and the semi-analytical solution of the shallow arch. The governing equation for the primary symmetric mode of the arch under external load was derived and expressed simply by using parameters. The semi-analytical solution of the equation was obtained using the Taylor series and the stability of the system for the constant load was analyzed. As a result, we can classify equilibrium points by root of equilibrium equation, and classified stable, asymptotical stable and unstable resigns of equilibrium path. We observed stable points and attractors that appeared differently depending on the shape parameter h, and we can see the points where dynamic buckling occurs. Dynamic buckling of arches with initial condition did not occur in low shape parameter, and sensitive range of critical boundary was observed in low damping constants.

• 전력전자학회논문지
• /
• 제3권1호
• /
• pp.77-84
• /
• 1998

본 논문에서는 비선형상태피드백을 적용한 무효전력보상기의 제어시스템을 설계하여 시뮬레이션과 축소모형 실험에 의한 성능해석에 관해 기술하였다. 무효전력 보상기의 수리모형을 3상 등가회로와 대표적인 동작점에 대한 상태방정식을 이용하여 도출하였으며, 비선형 상태피드백을 고려한 무효전력 보상기의 동특성을 표현하는 전달함수를 유도하였다. 또한 근궤적을 이용한 시스템 안정도 해석을 실시하여 제어시스템 설계를 실시하였다. 고안된 제어시스템의 성능해석은 EMTP를 이용한 시뮬레이션과 축소모형 실험을 통해 검증하였는데, 검증결과 고안된 제어시스템은 송전계통의 무효전력보상에 우수한 성능을 갖음이 확인되었다.

• 한국전기전자재료학회논문지
• /
• 제16권9호
• /
• pp.783-789
• /
• 2003

The winding problems of traction motor are the major determinant of motor's life. The root cause of winding failure is gradual deterioration of the insulation due to thermal, electrical, mechanical and environmental stresses. The aging of the insulation reduces the electrical and mechanical strength of the insulation. At same point, a voltage surge or mechanical shock from a traction motor start will fracture or break down the insulation. To achieve the expected life usually requires extensive laboratory evaluation of the insulation systems and the use of accelerated aging tests. There are several nondestructive test available for checking, the condition of motor insulation, the probable extent of aging, and the rate of which aging is taking place. So the insulation characteristics of stator coil were each analyzed by measurement of dielectric loss(tan$\sigma$), capacitance and partial discharge. The method of diagnosis is able to analyze the insulation condition and evaluate the life of the traction motor.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 춘계학술대회
• /
• pp.2017-2022
• /
• 2004

There are multistage preheaters in the power generation plan to improve the thermal efficiency of the plant and to prevent the components from the thermal shock. The energy source of these heaters comes from the extracted two phase fluid of working system. These two-phase fluid can cause the so-called Flow Accelerated Corrosion(FAC) in the extracting piping and the bubble plate of the heater for example, in case of point Beach Nuclear Power Plant and in the Wolsung Nuclear Power Plant. The FAC is due to the mass transport of the thin oxide layer by the convection. FAC is dependent on many parameters such as the operation temperature, void fraction, the fluid velocity and pH of fluid and so on. Therefore, in this paper velocity was calculated by FLUENT code in order to find out the root cause of the wall thinning of the feedwater heaters. It also includeed in the fluid mixing analysis model are around the number 5A feedwater heater shell including the extraction pipeline. To identify the relation between the local velocities and wall thinning, the local velocities according to the analysis results were compared with distribution of the shell wall thicknes by ultrasonic test.

• 한국분무공학회지
• /
• 제9권4호
• /
• pp.24-30
• /
• 2004

Feedwater flowing tube side of number 5 high pressure feedwatrr heaters was heated by extracting steam from high pressure turbine and draining water from moisture separators and number 6 high pressure feedwater heaters and supplied into steam generators. Because the extracting steam from the high pressure turbine is two phase fluid of high temperature, high pressure, and high speed and flows to inverse direction after impinging to impingement baffle. the shell wall of the number 5 high pressure feedwater heater may be affected by flow accelerated corrosion. On May 14, 1999, Point Beach Nuclear Plant (PBNP) with operating at full power experienced a steam leak from rupture of shell side of number 4B feedwater heater. Also, d domestic nuclear power plant experienced a severe wall thinning of shell side of number 5A and 5B feedwater heaters. This paper describes the fluid mixing analysis study using PHOENICS code in order to get at the root of the shell wall thinning of the feedwater heaters. The sections included in the fluid mixing analysis model are around the number 5h feedwater heater shell including the extracting pipeline. To identify the relation between the local velocities and wall thinning. the local velocities according to the analysis results were compared with the distribution of the shell wall thickness by ultrasonic test.

• Restorative Dentistry and Endodontics
• /
• 제43권2호
• /
• pp.15.1-15.7
• /
• 2018

Objectives: The present study aimed to evaluate the shaping ability of 2 thermally treated nickel-titanium reciprocating systems in simulated curved canals. Materials and Methods: Forty simulated canals were prepared to apical size 25 using Reciproc Blue R25 (VDW) and WaveOne Gold Primary (Dentsply Sirona) instruments. Standard pre- and post-preparation images were taken and superimposed. The removal of resin material was measured at 5 standard points: the canal orifice, halfway between the canal orifice and the beginning of the curve, the beginning of the curve, the apex of the curve, and the end-point of the simulated canal. The data were analysed using the independent sample t-test with a 5% significance threshold. Results: The canals in which Reciproc Blue R25 was used showed a significantly greater widening than those in which WaveOne Gold was used at 4 of the 5 measurement points (p < 0.05). The Reciproc Blue R25 instrument removed significantly more resin from the inner aspect of the curve at 2 of the 5 points and similar amounts at the remaining 3 points. At the 2 apical points, there was no significant difference between the Reciproc Blue R25 and WaveOne Gold Primary instruments. Conclusion: Both instruments respected the original canal anatomy; however, WaveOne Gold resulted in a more conservative shape with less transportation.

• 대한지역사회영양학회지
• /
• 제5권4호
• /
• pp.598-607
• /
• 2000

The purpose of this study was to investigate the intake, preference, and utilization of kimchi in female high school students. A questionnaire was used as the instrument of investigation. The subjects were 371 female high school students in Chonbuk province. More than 80% of the subjects had eaten 8 kinds of kimchies Korean cabbage kimchi, cubed radish kimchi, radish leaves kimchi, green onion kimchi, salted cucumber, watery radish kimchi, radish root & leaves kimchi, and Korean wild radish kimchi. The subjects living in urban areas ate more stalk of sweet potato kimchi and leaf mustard kimchi, however the subjects living in rural areas ate more sedum kimchi. The subjects in large families ate more leaf mustard kimchi and sedum kimchi. The preferred kinds of kimchi were radish kimchi, Korean cabbage kimchi, cubed radish kimchi, and cucumber radish kimchi. Seventy-four point four percent of the subjects liked kimchi, whereas 1.6% of them disliked it. The reason eating kimchi was 'custom'(59.0%), 'taste'(30.7%), 'nutrition'(4.3%), 'traditional flod'(2.7%), and 'parents advice'(2.7%). 38.4% of the subjects in urban area ate kimchi for taste whereas 25.0% of them in rural area did. They prefefrred 'well fermented', 'hot', and 'very pungent' kimchi. The preferred dishes made with kimchi were stir-fried rice with kimchi, kimchi stew, pan-fried kimchi, and rice with bean sprouts & kimchi.

• 한국임상수의학회지
• /
• 제34권1호
• /
• pp.58-60
• /
• 2017

An 11-year-old, castrated Maltese dog presented with a 3-week history of periocular swelling, epiphora, and intermittent strabismus. On examination, a foreign body was observed in the anterior chamber, along with orbital cellulitis. Severe gingivitis and plaque accumulation were also diagnosed. The foreign body was surgically removed, and dental prophylaxis and dental extraction were performed. The foreign body entrance could not be found intraoperatively, and the foreign body, later identified as a feather, was removed through a clear corneal incision. The right maxillary molar, which had periodontal inflammation, was also extracted. One day postoperatively, severe hypopyon developed, although the periocular swelling was reduced. These signs persisted despite topical and systemic antibiotic and anti-inflammatory therapy; therefore, the right eye was enucleated 1 week later. Intraoperatively, a fistula was found connecting the orbital medial wall, right maxillary molar root, and sclera. The fistula entered the dorsomedial sclera approximately 7 mm behind the limbus. Enterobacteria were cultured from the area. Foreign bodies can enter the anterior chamber not only through the cornea, but also through the mouth. Therefore, when the entry point cannot be found in the cornea, a careful dental examination is required, and the foreign body must be removed through the sclera rather than the cornea.