• 한국가시화정보학회:학술대회논문집
• /
• 한국가시화정보학회 2003년도 추계학술대회 논문집
• /
• pp.35-38
• /
• 2003

Simultaneous measurement of velocity and concentration fields in a stirred mixer flow using a combined Stereo-PIV/Planar-LIF technique is carried out. Instantaneous velocity fields and concentration fields represent the local flow characteristics. A baffle is perpendicularly attached to the Wall to remove inactive region which shows very slow dispersion. It is found that the baffle produces tip vortex and breaking the divided streamline, so that mixing efficiency could be increases significantly.

• 대한치과의사협회지
• /
• 제55권10호
• /
• pp.733-737
• /
• 2017

Successful osseo-integration of dental implants that Dr. Bronemak reported in 1965 had been ground-breaking research in the restorative dentistry for the missing dentition. Clinical application of dental implants in the restorative dentistry has begun with the role of retention and support for the complete denture, beyond the functional recovery in partially missing area, and succeeds in the cosmetic recovery for anterior missing area. Recently, immediate implantation and loading after the extraction have been preferred by many excellent clinicians especially on maxillary anterior missing area, because they want to prevent from the absorption of residual alveolar bone. But it is hard to decide immediate loading for common clinicians also, because it is difficult for them to convict proper osseo-integration. In this article, immediate implantation and delayed loading case on maxillay anterior region have been introduced and predictable prosthetic procedure for the esthetic result has suggested.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2005년도 추계학술대회 논문집
• /
• pp.671-675
• /
• 2005

In this paper, Development of propulsion system using IPM(Intelligent Power Module) for DC electric vehicle is proposed. Designed propulsion system is comprised of inverter stack which includes 6 IPM, BCH(Breaking Chopper) unit, FC(Filter Capacitor), Control unit. IPM can compose propulsion system simple by including gate drive circuit and protection circuit. Inverter stack is designed as a simple structure using IPM and non clamp capacitor. VVVF Inverter control is used the vector control strategy at low velocity region and slip frequency-control strategy at high velocity region. Designed propulsion system proves the performance through test and revenue service.

• 조명전기설비학회논문지
• /
• 제28권1호
• /
• pp.29-35
• /
• 2014

The purpose of this paper is the rotor design of a single-phase LSPM(Line-start permanent magnet) motor. A single-phase LSPM motor has a permanent magnet in the rotor that is same as induction motor. For that reason, magnet is operated by breaking torque in starting region and alignment torque in driving region. Therefore, we need the design process considering the trade-off relationship. In this paper, we propose the design process of a single-phase LSPM motor for a high starting torque and efficiency with FEM. And we use Taguchi Method for considering tolerance in manufacture. Finally, we compared the LSPM motor that is designed in this paper and conventional induction motor.

• 대한토목학회논문집
• /
• 제10권4호
• /
• pp.151-158
• /
• 1990

불규칙파에 의하여 형성된 쇄파대에서의 확산은 여러가지 요인에 기인한다고 볼 수 있다. 개개파의 쇄파에너지로 발생되는 난류형상, 유속의 공간변화에 의한 영향, 쇄파대 폭의 확장과 함께 나타나는 잉여파응력(Excess Momentum Fluxes or Radiation Stresses)의 불규칙 중첩에 의한 영향 등이며 이로 인하여 연안류는 보다 완만한 곡선을 나타낼 것이다. 본 연구에서는 단순파를 중첩시켜 표현하는 스펙트럼파 모델을 ${\kappa}-{\varepsilon}$ 모델과 연안류 모델에 접속시켜 운용할 수 있는 모델시스템을 개발하여 현장 관측자료에 적용하였다. 적용결과, ${\kappa}-{\varepsilon}$ 모델은 쇄파대 확산에 있어 난류확산의 영향과 불규칙한 응력중첩이 영향 모두를 잘 재현할 수 있음을 알 수 있었다. 또한, 본 수치모형에서는 고려치 못하였지만, 파 스펙트럼간 에너지의 비선형 전도효과도 연안류분포에, 특히 수심이 작은 연안 가까이에서, 무시할 수 없을 정도의 영향을 미치는 것으로 나타났다.

• 한국해안·해양공학회논문집
• /
• 제20권2호
• /
• pp.148-156
• /
• 2008

심해역 파랑모형인 WAM에 쇄파와 삼파 상호작용을 추가하여 모형의 적용영역을 천해역으로 확장하였다. 확장된 모형의 검증을 위해 Chawla et al.(1998) 과 Beji and Battjes(1993)의 수리모형 실험에 본 모형을 적용하여 천해역에서의 파랑변형 및 비선형 3파 상호작용의 수치모의 기능을 확인하였고, 계산된 수치모의 결과들은 수리실험의 계측결과와 잘 일치하였다. 그리고 실제 해역에서의 적용성을 검토하기 위해 태풍 매미에 대한 파랑 모의에 적용하였고, 계산 결과를 거제, 부산, 울산에서의 관측치와 비교하였는데 만족스러운 일치를 보여주었다.

• Geomechanics and Engineering
• /
• 제3권3호
• /
• pp.219-231
• /
• 2011

Waste fills resulting from coal mining should consist of large, free-draining sedimentary rocks fragments. The successful performance of these fills is related to the strength and durability of the individual rock fragments. When fills are made of shale fragments, some fragments will be durable and some will degrade into soil particles resulting from slaking and inter-particle point loads. The degraded material fills the voids between the intact fragments, and results in settlement. A laboratory program with point load and slake durability tests as well as thin section examination of sixty-eight shale samples from the Appalachian region of the United States revealed that pore micro-geometry has a major influence on degradation. Under saturated and unsaturated conditions, the shales absorb water, and the air in their pores is compressed, breaking the shales. This breakage was more pronounced in shales with smooth pore boundaries and having a diameter equal to or smaller than 0.060 mm. If the pore walls were rough, the air-pressure breaking mechanism was not effective. However, pore roughness (measured by the fractal dimension) had a detrimental effect on point load resistance. This study indicated that the optimum shales to resist both slaking as well as point loads are those that have pores with a fractal dimension equal to 1.425 and a diameter equal to or smaller than 0.06 mm.

• 대기
• /
• 제21권1호
• /
• pp.69-83
• /
• 2011

The synoptic condition of clear-air turbulence (CAT) events occurred over South Korea is investigated, using the Regional Data Assimilation and Prediction System (RDAPS) data obtained from the Korea Meteorological Agency (KMA) and pilot reports (PIREPs) collected by Korea Aviation Meteorological Agency (KAMA) from 1 Dec. 2003 to 30 Nov. 2008. Throughout the years, strong subtropical jet stream exists over the South Korea, and the CAT events frequently occur in the upper-level frontal zone and subtropical jet stream regions where strong vertical wind shears locate. The probability of the moderate or greater (MOG)-level turbulence occurrence is higher in wintertime than in summertime, and high probability region is shifted northward across the jet stream in wintertime. We categorize the CAT events into three types according to their generation mechanisms: i) upper-level front and jet stream, ii) anticyclonically sheared and curved flows, and iii) breaking of mountain waves. Among 240 MOG-level CAT events reported during 2003-2008, 103 cases are related to jet stream while 73 cases and 25 cases are related to the anticyclonic shear flow and breaking of mountain wave, respectively.

• Mycobiology
• /
• 제50권6호
• /
• pp.408-419
• /
• 2022

Filamentous fungi that could be classified into Aspergillus flavus/oryzae were isolated from traditionally fermented meju commercially available in Korea. The samples were analyzed for aflatoxin B1 and ochratoxin A contamination by HPLC; however, no toxin was detected. In addition, fungal and bacterial metagenomic sequencing were performed to analyze the microbial distribution in the samples. The results revealed that the distribution and abundance of fungi and bacteria differed considerably depending on the production regions and fermentation conditions of the meju samples. Through morphological analysis, ITS region sequencing, and assessment of the aflatoxin-producing ability, a total of 32 A. flavus/oryzae strains were identified. PCR analysis of six regions with a high mutation frequency in the aflatoxin gene cluster (AGC) revealed a total of six types of AGC breaking point patterns. The A. flavus/oryzae strains did not exhibit the high amylase activity detected in the commercial yellow koji strain (starter mold). However, their peptidase and lipase activities were generally higher than that of the koji isolates. We verified the safety of the traditionally fermented meju samples by analyzing the AGC breaking point pattern and the enzyme activities of A. flavus/oryzae strains isolated from the samples. The isolated strains could possibly be used as starter molds for soybean fermentation.

• 한국농림기상학회지
• /
• 제18권3호
• /
• pp.162-169
• /
• 2016

기준기상위험이란 한 지역의 평년기후조건이 작물재배에 미칠 수 있는 '농업기상학적 피해가능성'으로서, 동일 작물 재배 시 지역에 따른 재해위험을 비교하는 기준이 된다. 지구온난화로 인하여 겨울 온도는 상승할 것으로 예상되지만, 기상이변의 빈도 또한 늘어날 것으로 전망되기 때문에 미래 기후조건에서 과수의 동해, 상해 등 저온에 의한 재해위험이 주목 받고 있다. 그러나 기후의 변화는 과수 생물계절도 변화시키므로 기상조건에 근거한 단순한 재해위험 전망은 기후변화적응의 실용측면에서 별 도움이 되지 못한다. 본 연구에서는 전국 주요 지역의 과거 및 기후변화시나리오를 이용하여 배, 복숭아, 사과의 생물계절을 예측하고 생육단계별 기온과의 상호작용에 근거하여 저온 유래 기준기상위험을 계산함으로써 미래의 재해가능성을 전망하였다. 휴면해제일은 미래로 갈수록 늦어질 것으로 전망되었으며, 발아일과 개화일의 경우 빨라질 것으로 예상되었다. 대구, 전주, 목포의 경우 휴면해제일의 지연 정도가 미래로 갈수록 커졌으며 발아일과 개화일의 경우 서울, 인천 지역이 다른 지역에 비해 늦게 나타났다. 서울과 인천, 대구와 전주, 부산과 목포가 서로 비슷한 양상을 나타내었다. 휴면기 동안에는 전 지역이 동해에 안전하였으나 휴면해제-발아기 동안에는 전 지역이 동해에 취약하였고, 발아기-개화기의 위험은 미래로 갈수록 대체로 낮아졌지만 지역에 따라 위험이 커지는 곳도 있었다.