• 한국재료학회지
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• 제11권8호
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• pp.363-363
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• 2001

PDP용 녹색 형광체의 발광특성을 개선시키기 위해 고안된 액상의 화학적 합성법을 사용하여 조성식이 $Zn_{2-x}$ $SiO_4$:xMn(x=0.05, 0.08)인 형광체를 입자크기가 0.5~2$\mu\textrm{m}$로 조절하여 제조하였다. 제조된 형광체 입자는 구상이며 잘 분산된 형상을 봉주었고, 고상반응법에 비해 상대적으로 낮은 $1080^{\circ}C$에서 willemite구조의 단일상을 얻을 수 있었다. 또한 진공 자외선 영역의 147 nm의 여기원을 사용하여 광발광 특성을 조사하였다. 입자의 크기가 1$\mu\textrm{m}$이고 Mn의 도핑양이 8mole%일 때, 상용 형광체와 비교하여 발광세기는 약 40% 향상되었고 색좌표는 x=0.24, y=0.69로 거의 일치하는 결과를 얻을 수 있었다. 측정된 형광체의 잔광시간은 7.8ms이었다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제21회 추계학술대회 논문집
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• pp.271-277
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• 2003

최근 환경 소음이 사회적인 문제로 대두되고 있는 가운데, 생활수준의 향상으로 저소음화에 대한 요구가 증가되고 있는 실정이다. 이와 같이 소음에 관한 일반인들의 관심이 높아지면서 생환주변에서 주요 소음원으로 지적되고 있는 회전기계, 특히 가전제품을 비롯한 유동관련 기계류의 소음을 낮추기 위한 노력이 절실히 요구되고 있다. 본 소평팬에 대한 연구에서는 음압 및 음향인텐시티를 이용하여 소음원을 해석하였다. 이때, 광센서를 이용한 축류형 팬의 동기화가 수행되어졌고, 팬 형상에서 정확한 소음원의 위치를 규명하기 위한 기록시간의 결정이 제안되어졌다. 소음 발생하는 위치를 규명하였고, 지향성 연구를 통하여 축류형 팬의 방사형태를 결정하였으며, 음의 흐름도를 가시화 하였다.

• 한국분무공학회지
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• 제12권1호
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• pp.38-44
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• 2007

Since the Liquid Phase LPG injection (LPLI) system has Advantages in power generation and emission characteristics compared to the mixer-type fuel-supply system, a variety of studies regarding LPLi system has been conducted and its applications are made in automobile industry. However, the heat extraction due to the evaporation of liquid fuel, causes not only a post-accumulation of fuel but also an icing phenomenon which is a frost of moisture in the air around the nozzle tip. Since there exists a difficulty in the accurate control of air fuel ratio in both fuel supply systems, it can result in poor engine performance and a large amount of harmful emissions. This research examines the characteristics of icing phenomenon and develops anti-icing bushing to prevent an icing on the surface of the injection tip. It was found that n-butane, which has a relatively high boiling point ($-0.5^{\circ}C$), was a main species of post-accumulation. Also the results show that the post-accumulation problem was allevaited the utilization of a large inner to outer bore ratio and smooth surface roughness. In addition, an icing phenomenon and its formation process were found to be mainly affected by the humidity and the temperature of inlet air in an inlet duct. Also, it was observed that an icing phenomenon is lessened using aluminum bushing whose end coincides with the end of fuel injection tip in length.

• 농업과학연구
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• 제42권4호
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• pp.415-421
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• 2015

Ca is material to used in Chinese cabbage (Brasica rapa L. spp. pekinensis). The variation of inorganic ions and GSLs in Chinese cabbage cultivated to control additional Ca contents in slaked lime. The additional fertilizer of slaked lime differ four grade that 0 g (Ca-0), 0.28 g (Ca-1), 0.56 g (Ca-2), 0.84 g (Ca-3) are week intervals with a total of 8 times after transplanting. Inorganic ions in Chinese cabbage ('Bulam plus') were analyzed to use inductively coupled plasma atomic emission spectometry(ICP). The more additional slaked lime input, the more almost macronutrients contents were high except Ca. Ca contents were higher in Ca-0 (153.10) and lower in Ca-3 (130.55 mg/kg dry weight, DW). GSLs were identified based on peak retention time in previous results of our laboratory. Seven GSLs including two aliphatic (gluconapin, glucobrassicanapin), one aromatic (gluconasturtiin), four indolyl (glucobrassicin, neoglucobrassicin, 4-methoxyglucobrassicin, 4-hydroxyglucobrassicin) were detected using HPLC. Progoitrin, 4-methoxyglucobrassicin, and gluconasturtiin contents increased in proportion to the input in additional slaked lime. Total GSLs contents were Ca-0 (11.95), Ca-1 (17.02), Ca-2 (19.63), Ca-3 ($17.11{\mu}mol/g$ dry weight, DW). Total Ca and GSLs contents (Ca-1,2,3; mean 17.92) are higher than non treatment (Ca-0; $11.95{\mu}mol/g$ DW).

• 한국세라믹학회지
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• 제54권1호
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• pp.49-54
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• 2017

In this study, based on hydrolysis and condensation via $St{\ddot{o}}ber$ process of sol-gel method, synthesis of mono-dispersed silica nanoparticles was carried out with hydrophilic solvent. This operation was expected to be a more simplified process than that with organic solvent. Based on the sol-gel method, which involves simply controlling the particle size, the particle size of the synthesized silica specimens were ranged from 30 to 300 nm by controlling the composition of tetraethylorthosilicate (TEOS), DI water and ammonia solution, and by varying the stirring speeds while maintaining a fixed amount of ethanol. Increasing the content of DI water and decreasing the content of ammonia caused the particle size to decrease, while controlling the stirring speed at a high level of RPMs enabled a decrease of the particle size. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were utilized to investigate the success factors for synthesizing process; Field emission scanning electron microscopy (FE-SEM) was used to study the effects of the size and morphology of the synthesized particles. To analyze the dispersion properties, zeta potential and particle size distribution (PSD) analyses were utilized.

• 한국수소및신에너지학회논문집
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• 제26권2호
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• pp.89-95
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• 2015

Pollution emission control of the 20th century, for transportation energy, are being enhanced, and then as alternative to this, because hydrogen emit only water gas emissions to be environmentally friendly energy, so hydrogen as a sustainable clean energy is in the limelight. Used in compressed natural gas engines to mix hydrogen and natural gas in both domestic and international technology development and demonstration is being carried out. The hydrogen-compressed natural gas(HCNG) charging infrastructure can be used to build a hydrogen infrastructure in the transitional aspects of a future hydrogen economy society. In this paper, for a demonstration of HCNG charging infrastructure we made and operated a $30Nm^3/h$ hydrogen generating unit and analyzed the result of the operation. We was identified the operating conditions of a reforming reactor and water gas shift reactor from an analysis result, the thermal efficiency was calculated according to the operating conditions of the total hydrogen production process.

• 전기전자학회논문지
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• 제17권4호
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• pp.398-406
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• 2013

핵의학 영상 기기인 양전자 방출 단층 촬영 장치(Positron emission tomography: PET)와 같은 진단기기는 방사성의약품을 인체에 주입하여 질병을 진단한다. 이 때 사용되는 방사성의약품은 안전성을 위하여 적절한 수소 이온농도를 가져야 한다. 일반적으로 방사성 의약품의 수소 이온 농도를 측정하는 과정에서 흔히 사용되는 것이 pH시험지이다. 표본을 pH 시험지에 떨어뜨려 pH 시험지의 변색 정도를 표준색상표(Standard color chart)와 비교하여 표본의 pH를 알 수 있다. 그러나 이 방법은 측정자의 경험 정도에 따라 pH 측정값에 차이가 발생할 수 있다. 또한 pH 메타기는 고감도의 센서를 사용함으로 오염에 주의해야 한다. 이러한 불편함을 고려하여 쉽고 간단하게 정확한 pH를 측정하기 위한 새로운 장치 제작과 영상 기반 알고리즘을 통한 소프트웨어를 개발하였다. 이렇게 개발한 장치는 최종적으로 방사성의약품의 생산 시 품질관리(QC) 통합 제어 시스템으로 사용된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.764-769
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• 2001

Recently, according to increase in the requirement of electric power, a thermoelectric power plant equipped with pulverized coal combustion system is highly valued, because coal has abundant deposits and a low price compared with others. For efficient use of coal fuel, most of plant makers are studying to improve combustion performance and flame stability, and reduce pollutant emission. One of these studies is how to control the profile of particle injection and velocity dependant on coal nozzle. Basically, a mixed flow of gas and particle in coal nozzle is required to have appropriate injection and concentration distribution at exit to achieve flame stability and low pollutant, but it is very difficult to obtain that without help of a coal separating device within nozzle. In this study, each distribution of air and coal flow rate is measured for the coal nozzle with coal separator developed by us. The coal concentration at exit is various according to inlet swirl values and positions of coal separator. Also pressure drop is measured for various operating conditions of this nozzle. From these results, we can find the separation characteristic of new developed coal separator, and select proper operation range of coal nozzle. When this coal nozzle is applied to actual plant, these investigations will be very useful to confirm the shape of coal separator to have efficient particle injection.

• 대한후두음성언어의학회지
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• 제2권1호
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• pp.15-19
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• 1986

Our report refers to occidental vocal techniques from Greece until today. It is remarkable that even with poor anatomy knowledge, there were advices on styles given from very early periods, for both church and secular singing. During the 18th century, the names of "vox pectoris", "vox guturris" and "vox capitis" appear, nominations that somehow remain nowadays with great confusion about source of sound production and results of resonance. Vocal occidental styles developed different kinds of requirements from the singers, that had to adapt their vocal Possibilities to them. The same happened with "pop" song. Nowadays, all kinds of singers must have a conscious knowledge of its voice management to prevent vocal disturbances. We consider that the technique is the same, even when the singer has to sing Wagner, Debussy, Sconberg, Piazzola or Gershwin. The big changes occured at resonance levels, and because these different use of the vocal resonators the effects are quite different. In summary, the big differences on classical the effects are quite different. In summary, the big differences on classical and pop song are done on the different use of the resonators and its effects on the vocal tract. "Pop" singers, men and women, should be taught to use both registers, "modal" and "falsetto" to be able to reach the complete range of their songs without any harm to their larynxes. In our opinion, a good singing technique means that it could be adapted to every stylistic need. The same technique is adapted to the popular singer as well. The main difference lays on the use of resonators, pretty strong in the classic singer, weaken in the popular singer, on the volume and on the total extension of the voice. Breathing control, effortless emission and the use of "passage" at the right point should be taught to all singers, regardless of their style. (omitted)

• Asian Pacific Journal of Cancer Prevention
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• 제16권15호
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• pp.6279-6284
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• 2015

Opisthorchis viverrini (OV)-induced cholangiocarcinoma (CCA) is an important cancer in the Great Mekong region, particularly in Thailand. Limitations of treatment options and the lack of an effective diagnostic tool for early detection of CCA are major concerns for the control of this type of cancer. The aim of the study was to investigate anti-CCA activity of the ethanolic extract of Atractylodes lancea (Thunb.) DC., and the applicability of positron emission tomography-computed tomography (PET-CT) as a tool for detection and monitoring the progression of CCA in Opisthorchis viverrini (OV)/dimethylnitrosamine (DMN)-induced CCA hamsters. Male Syrian hamsters were used for toxicity tests and anti-CCA activity evaluation. Development of CCA was induced by initial feeding of 50 metacercariae of OV, followed by drinking water containing 12.5 ppm of DMN in hamsters. The ethanolic extract of A. lancea (Thunb.) DC. was administered orally for 30 days. PET-CT was performed every 4 weeks after initiation of CCA using 18F-fluorodeoxyglucose ($^{18}F-FDG$). Results from the present study suggest that the ethanolic extract of A. lancea (Thunb.) DC. rhizome exhibited promising anti-CCA activity and safety profile in the OV/DMN-induced hamster model. To successfully apply PET-CT as a tool for early detection of tumor development and progression, modification of radiolabeling approach is required to improve its specificity for CCA cells.