• 연구논문집
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• 통권27호
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• pp.87-99
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• 1997

Present paper describes on/off design performance of a 50KW turbogenerator gas turbine engine for hybrid vehicle application. For optimum design point selection, relevant parameter study is carried out. The turbogenerator gas turbine engine for a hybrid vehicle is expected to be designed for maximum fuel economy, ultra low emissions, and very low cost. Compressor, combustor, turbine, and permanent-magnet generator will be mounted on a single high speed (82,000 rpm) shaft that will be supported on air bearings. As the generator is built into the shaft, gearbox and other moving parts become unnecessary and thus will increase the system's reliability and reduce the manufacturing cost. The engine has a radial compressor and turbine with design point pressure ratio of 4.0. This pressure ratio was set based on calculation of specific fuel consumption and specific power variation with pressure ratio. For the given turbine inlet temperature, a rather conservative value of $1100^\circK$ was selected. Designed mass flow rate was 0.5 kg/sec. Parametric study of the cycle indicates that specific work and efficiency increase at a given pressure ratio and turbine inlet temperature. Off design analysis shows that the gas turbine system reaches self operating condition at N/$N_{DP}$ = 0.53. Bleeding air for turbine stator cooling is omitted considering low TIT and for a simple geometric structure. Various engine performance simulations including, ambient temperature influence, surging at part load condition. Transient analysis were performed to secure the optimum engine operating characteristics. Surge margin throughout the performance analysis were maintained to be over 80% approximately. Validation of present results are yet to be seen as the performance tests are scheduled by the end of 1998 for comparison.

• The Plant Pathology Journal
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• 제22권2호
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• pp.155-160
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• 2006

A strain of Pepper mottle virus (PepMov) was isolated from chili pepper plants in Korea. In host range study, this virus, designated PepMoV-SNU1, shared most characteristics with PepMoV isolates reported previously. Thermal inactivation point ($45^{\circ}C\;to\;75^{\circ}C$) and dilution end point ($10^{-1}\;to\;10^{-4}$) of PepMoV-SNU1 showed differences depending on the propagation hosts. Cylindrical and pinwheel-shaped inclusions were always observed in pepper leaf tissues infected with the virus alone. Unexpectedly, a special structure of pinwheel shaped inclusion surrounded with unknown small spots was also observed in the leaf section when co-infected with a strain of pepper mild mottle virus. The partial sequence of coat protein gene and 3' untranslated region of PepMoV-SNU1 showed 98% identity with those of other PepMoV isolates. A primer pair derived from 3' end of the coat protein gene and poly A tail regions were designed. Optimal detection condition of PepMoV-SNU1 by RT-PCR was tested to determine appropriate annealing temperature and additional volumes of oligo-dT (18-mer), dNTP, and Taq polymerase. Under the optimized condition, an expected 500 Up PCR-product was detected in pepper leaves infected with PepMoV-SNU1 but not in healthy plants.

• 대한화학회지
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• 제5권1호
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• pp.42-47
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• 1961

A titration of a small amount of iron with standard potassium ferrocyanide using potassium thiocyanate as indicator has been studied. A sample solution containing $0.1{\sim}1.0$ mg. $Fe^{3+}$ in 60 ml. is pipeted into 100 ml. Erlenmyer flask and the pH of the solution is adjusted to $1.5{\sim}3.0$ with 0.1 N or 1 N $HNO_3$ and $NH_4OH.$ To this solution one ml. of 1 M KCNS solution as indicator is added. The solution colored by iron thiocyanate complex is titrated with 1/200 M or 1/400 M standard solution of potassium ferrocyanide from a 5 ml. micro-buret. Near the end point, when the color of sample changes from deep red to green, about 20 ml. of ether is added and shake the flask vigorously. The red color is extracted to the ether layer. To settle the ether layer a few drops of ethanol is added and then standard solution is added dropwise and shake vigorously. The end point is reached when the color of the ether layer disappears owing to the quantitative formation of $Fe_4[Fe(CN)_6]_3.$ In this titration, 0.lmg. of $Fe^{3+}$ can be determined within 1.0% of titration error, provided the following optimum conditions, i.e., pH $1.5{\sim}3.0$, final concentration of KCNS indicator; $0.01{\sim}0.02M$, at room temperature. The titration found to be interfered by the presence of slightly soluble salts, stable complex forming ions and the ions which would be reduced by ferrocyanide or oxidized by ferric ion.

• 전기학회논문지
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• 제61권8호
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• pp.1148-1152
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• 2012

The vegetable-based insulating oils are substitutes for mineral oils in oil-filled transformer. The important properties of vegetable insulating oil is their higher flash/fire point and biodegradability than conventional mineral oils. The large oil-filled transformer eliminate the risk of explosion and fire should the transformer fail and oil ignite owing to high flash/fire point of vegetable insulating oil. In addition, higher biodegradability of vegetable insulating oils can let the oil spill damage reduced. In this experiment, the real oil-filled transformers using mineral oil and vegetable oil have accelerated aging. After working on the 100% accelerated aging experiment were conducted comparing the transformer. The hottest-spot temperature using thermal coefficients were calculated to determin the degree of accelerated aging. As a result, apply mineral oil transformer in accordance with the accelerated aging life come to an end. In contrast, vegetable insulating oils showed the opposite characteristics. Vegetable insulating oil compared to the mineral oil are found to be an long life. As a result, the vegetable oil has a long-term stability.

• 한국축산식품학회지
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• 제30권3호
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• pp.373-384
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• 2010

The present paper describes the effect of cooking temperature on objective meat qualities and volatile components in beef longissimus lumborum. Twenty samples of lumbar vertebrae longissimus muscle from Australian Black Angus (grain-fed and chiller aged for 29 d) were screened. Samples were cooked at 50, 70 or $90^{\circ}C$ in a pre-heated water bath for 1 h and uncooked raw samples were used as control. The results revealed that elevating the heating temperature from 50 to $90^{\circ}C$ led to a significant (p<0.05) increase in WB-shear force, total energy required for WB-shear force, cooking loss, pH and soluble collagen content, whereas a significant (p<0.05) linear decrease in protein solubility was observed. The results also revealed that the WB-shear force at $70^{\circ}C$ was significantly (p<0.05) lower than that observed at $50^{\circ}C$ and $90^{\circ}C$. However, the effect of temperature on cooking loss and protein solubility was notably (p<0.05) higher at $70^{\circ}C$. The detectable volatile components were mostly produced from fat oxidation, and temperature effects on the generation of volatile components were significantly (p<0.05) greater for aldehydes (hexanal, benzaldehyde, nonanal and octanal) than for ketones and hydrocarbons (hexane, benzene, decan, toluene and 3-methylnonane).

• Journal of Animal Science and Technology
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• 제46권1호
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• pp.83-90
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• 2004

본 연구는 식염과 지방 그리고 여러 가열조건에 의한 pH 및 일반성분, 가열감량 및 단백질 용해성의 변화에 따른 단백질 분획의 변화에 대해 분석하였다 처리구에 따른 가열감량 (CL, %)은 지방의 첨가에 상관없이 식염을 2%첨가한 경우 식염을 첨가하지 않은 경우에 비하여 약 1/2배 정도 낮은 가열감량을 보였다. 한편, 식염 무첨가구의 경우 지방을 첨가한 경우 가열감량은 유의적으로 낮았으나, 식염 2%첨가구는 지방 첨가에 따른 가열감량의 유의적 차이가 나타나지 않았다. 그리고 가열온도에 따른 가열감량은 $66^{\circ}C$까지는 점진적으로 증가하다가 $68^{\circ}C$ 보다 높은 가열온도에서 유의적으로 증가하는 경향을 보였다. 식염 무첨가구와 식염 2% 첨가구 사이에서는 단백질 용해성의 유의적인 차이가 없었으나 지방이 첨가된 경우 상대적인 단백질 함량의 감소로 단백질 용해성이 유의적으로 감소하였다. 가열 온도가 높아짐에 따라 용해성의 감소가 현저히 나타났으나 $68^{\circ}C$ 이상의 가열온도에서는 단백질 용해성이 유의적 차이 없이 일정한 수준을 유지하였다. 추출한 근장 단백질이 각 처리구별 가열온도에 따른 단백질 분획을 분석하기 위해 전기영동을 실시한 결과 식염, 지방 그리고 가열에 따라 특이적으로 반응한 것은 36 과 66 kDa의 분자량을 가진 근장 단백질 분획이었다. 이러한 단백질 분획은 최종가열온도가 66 ${\sim} 70^{\circ}C$에서 급격히 thtlfehladmfhTJ 돈육의 최종 가열온도 측정을 위한 지시제로 사용될 수 있을 것으로 판단된다.

• 한국재료학회지
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• 제14권10호
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• pp.688-695
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• 2004

The capacitor contact barrier(CCB) layers have been introduced in the FeRAM integration to prevent the Pt/Al reaction during the back-end processes. Therefore, the interdiffusion and intermetallic formation in $Pt(1500{\AA})/Al(3000{\AA})$ film stacks were investigated over the annealing temperature range of $100\sim500^{\circ}C$. The interdiffusion in Pt/Al interface started at $300^{\circ}C$ and the stack was completlely intermixed after annealing over $400^{\circ}C$ in nitrogen ambient for 1 hour. Both XRD and SBM analyses revealed that the Pt/Al interdiffusion formed a single phase of $RtAl_2$ intermetallic compound. On the other hand, in the presence of TiN($1000{\AA}$) barrier layer at the Pt/Al interface, the intermetallic formation was completely suppressed even after the annealing at $500^{\circ}C$. These were in good agreement with the predicted effect of the TiN diffusion barrier layer. But the conventional TiN CCB layer could not perfectly block the Pt/Al reaction during the back-end processes of the FeRAM integration with the maximum annealing temperature of $420^{\circ}C$. The difference in the TiN barrier properties could be explained by the voids generated on the Pt electrode surface during the integration. The voids were acted as the starting point of the Pt/Al reaction in real FeRAM structure.

• 한국추진공학회지
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• 제20권4호
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• pp.26-33
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• 2016

추진기관의 주요 연료로 사용되는 액체 탄화수소 연료의 초임계 천이특성을 분석하기 위해서 Methylcyclohexane (MCH)의 상변화 가시화 및 MCH와 Decane의 포화곡선 측정실험을 수행하였다. 압력 정체구간은 임계점 부근에서 급격한 비열의 상승으로 존재하며, 정체구간이 종료되는 시점부터 임계점까지 임계단백광이 관측되었다. 또한, 초임계로 완전히 천이되면서 상의 경계가 사라지고 강한 밀도 구배를 관측할 수 있었다. 실험 포화온도 곡선과 수치적 데이터를 비교한 결과 단일 탄화수소계열 연료는 실험과 수치데이터가 거의 일치하는 경향을 보였으나, 혼합탄화수소계열연료의 임계점 예측에서는 다소 차이를 보였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.951-955
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• 2004

Piezoelectric(PZT) actuator can substitute for solenoid which is used in fluid control field because it has faster response times and no possibility of explosion. Besides, it is available in a high temperature and it has low energy consumption. In this study, pneumatic micro valve, bimorph type PZT actuator using the softner type PZT, carbon plate as a shim and its controller circuit were suggested and investigated. Performance tests and characteristics analysis, such as displacement, force, hysteresis and frequency properties, were carried out. The displacement of the actuator measured at the end point was 63 ${\mu}m$., force of the actuator was 0.052 N and maximum operating frequency was 15Hz. Also, characteristics of the micro valve with PZT actuator were evaluated in a testing system. The results show that the suggested PZT actuator is suitable for micro valve.

• 오토저널
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• 제11권6호
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• pp.48-56
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• 1989

A shock tube technique was developed in which a freely falling droplets column produced by an ultrasonic atomizer was ignited behind reflected shock. In the present study, the effects of turbulent mixing on the ignition delay of a cetane was decided, also, ignition process was investigated. For the purpose of disturbance of droplets column and mixing, authors installed turbulent lattice in shock tube. Usually, the ignition delay is so called Arrhenius plot which found break point in the Arrhenius plot on the high temperature side. The rate of misfiring increased rapidly below 1080K, but ignition took place from 838k and luminous flame was seen to spread over the whole section by turbulent lattice. Length, from end plate to turbulent lattice, was varied with 60,40,20mm. Also, ignition process was detected by Photo transistor. As a result, it was found that physical factors changed ignition delay greatly and turbulent mixing had a considerable effects in the ignition process.