• The Korean Journal of Petroleum Geology
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• v.2 no.2 s.3
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• pp.83-90
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• 1994

Thermal maturation and diagenesis of the Gyeongsang Supergroup in the Euiseong area are studied by means of organic geochemical techniques and illite crystallinity. Black mudrocks of the Singdong Group contain organic matter of $0.5{\~}2{\%}$ derived from higher plants, being compared to type Ⅲ. Thermal maturity of organic matter reached dry gas generation phase. Tmax by Rock Eval pyrolysis varies between $578^{\circ}C$ and $593^{\circ}C$ regardless of stratigraphic position and localities, and vitrinite reflectance is about 2.9 and $3{\~}4{\%}Ro$ in the Jinju and the Nagdong Formations, respectively. Vitrinite reflectance measurements indicate that the maturation is mainly due to burial and partly to be affected by post-depositional intrusions. Illite crystallinity values from the Nagdong, Hasandong, Jiniu Formations and part of the Iljig Formation are plotted around the boundary between diagenesis and anchizone, indicating dry gas generation stage. However, the values are not dependent on stratigraphic position. The values from the Iljig, Hupyeongdong, Geomgog, and Sagog Formations fall into the range of anchizone, probably resulted from the post-depositional intrusions which occur locally. Both organic geochemical and illite crystallinity data indicate thermal maturation stage of dry gas generation. Diagenesis of the Gyeongsang strata is mostly controlled by burial, and partly affected by post-depositional intrusions. Paleotemperature of the Sindong Group is estimated at around $200^{\circ}C$ on the basis of illite crystallinity.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.1
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• pp.63-69
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• 2023

'Carbon-neutrality Assessment based on Technology Application Scenario (CATAS)' provides an analysis of greenhouse gas (GHG) reduction effectiveness when applying carbon-neutrality technology to areas such as energy conversion, transportation, and buildings at certain spatial levels. As for the development scope of the model, GHG emission sources were analyzed for direct GHG emissions, and the boundary between direct and indirect emissions are set according to the spatial scope. The technical scope included nine technologies and forest sinks in the transition sector that occupies the largest portion of GHG emissions in the 2050 carbon neutral scenario. The carbon neutrality rate evaluation methodology consists of four steps: ① analysis of GHG emissions, ② prediction of energy production according to technology introduction, ③ calculation of GHG reduction, and ④ calculation of carbon neutrality rate. After the web-based CATAS-BASIC was developed, an analysis was conducted by applying the new and renewable energy distribution goals presented in the ｢2050 Greenhouse Gas Reduction Promotion Plan｣ of the Seoul Metropolitan Government. As a result of applying solar power, hydrogen fuel cell, and hydrothermal, the introduction of technology reduced 0.43 million tCO₂eq of 1.49 million tCO₂eq, which is the amount of emissions from the conversion sector in Seoul, and the carbon neutrality rate in the conversion sector was analyzed to be 28.94 %.

• Journal of Welding and Joining
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• v.30 no.1
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• pp.64-71
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• 2012

The characteristics of high heat input (342kJ/cm) EG (Electro Gas Arc) welded joint of EH36-TM steel has been investigated. The weld metal microstructure consisted of fine acicular ferrite (AF), a little volume of polygonal ferrite (PF) and grain boundary ferrite (GBF). Charpy impact test results of the weld metal and heat affected zone (HAZ) met the requirement of classification rule (Min. 34J at $-20^{\circ}C$). In order to evaluate the relationship between the impact toughness property and the grain size of HAZ, the austenite grain size of HAZ was measured. The prior austenite grain size in Fusion line (F.L+0.1 mm) was about $350{\mu}m$. The grain size in F.L+1.5 mm was measured to be less than $30{\mu}m$ and this region was identified as being included in FGHAZ(Fine Grain HAZ). It is seen that as the austenite grain size decreases, the size of GBF, FSP (Ferrite Side Plate) become smaller and the impact toughness of HAZ increases. Therefore, the CGHAZ was considered to be area up to 1.3mm away from the fusion line. Results of TEM replica analysis for a welded joint implied that very small size ($0.8\sim1.2{\mu}m$) oxygen inclusions played a role of forming fine acicular ferrite in the weld metal. A large amount of (Ti, Mn, Al)xOy oxygen inclusions dispersed, and oxides density was measured to be 4,600-5,300 (ea/mm2). During the welding thermal cycle, the area near a fusion line was reheated to temperature exceeding $1400^{\circ}C$. However, the nitrides and carbides were not completely dissolved near the fusion line because of rapid heating and cooling rate. Instead, they might grow during the cooling process. TiC precipitates of about 50 ~ 100nm size dispersed near the fusion line.

• Fire Science and Engineering
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• v.33 no.6
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• pp.120-125
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• 2019

A real-scale combustion test was conducted on a vinyl flooring in a divided space, with 50 mL of an inflammable liquid sprayed on it. The combustion behavior of the vinyl flooring was studied in real time, and the carbonization patterns of the surface and cross-sections of the carbonized vinyl floor were analyzed. When the flame ignited by gasoline reached its peak, a continuously flaming region, intermittent flaming region, plume region, etc., were formed. The combustion of 50 mL gasoline on vinyl flooring took 26 s, and a halo pattern was observed. This test involved spraying kerosene evenly on the vinyl flooring and attempting to ignite the flooring using a gas torch, which failed. After the combustion of the vinyl flooring was complete, its carbonized range was measured to be 600 mm in length and 380 mm in width, and the carbonized area was 1000 ㎟. Heat transformed the coated layer of surface of the carbonized vinyl flooring into a carbonized layer, which became harder. The analysis of cross-section of the boundary surface of the carbonized vinyl flooring using a stereoscopic microscope showed that the vinyl flooring was bubbling, and that the white boundary layer at the bottom of the coated layer had disappeared.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.34.1-34.1
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• 2009

1970년대 WernerKern에 의해서 개발된 RCA 습식 세정 공정은 이후 메가소닉 기술 개발과 더불어 현재까지반도체 세정 공정에서 필수 공정으로 알려져 있다. 하지만, 반도체패턴의 고집적화 미세화에 따라 메가소닉을 기반으로 하는 세정기술은 패턴 붕괴 및 나노 입자 제거의 한계를 드러내면서 난관에 봉착하고 있으며, 특히, 기존의 Batch식에서 매엽식으로 세정 방식이 전환은 새로운 개념의 메가소닉 기술 개발을 요구하게 되었다. 메가소닉을 사용한습식 세정공정은 메가소닉에 의한 캐비테이션 효과 (Cavitation Effect)에 따른 충격파 및음압 (Acoustic Streaming)에 의한 입자제거를 주요 메커니즘으로 한다. 메가소닉 주파수와 Boundary Layer 두께는, $\delta=\surd(2v/\omega)$($\delta$=두께, v=유체속도), $\omega=2{\pi}f$ (f=주파수), 으로 표현할 수 있다. 위의 식에 따르면, 메가소닉을 이용한 세정공정에서 주파수가 높아질수록 Boundary Layer의 두께가 감소하며, 이는제거 가능한 입자의 크기가 작아짐을 의미하며, 다시말해, 1 MHz 보다 2 MHz 메가소닉 세정장비에서 미세 입자 세정에 유리함을 예상할 수 있다. 본연구에서는 매엽식 세정장비를 사용하여, 1MHz 및 2MHz 콘-타입 (Cone-Type) 메가소닉 장치를 100nm이하 세정 입자에 대한 입자 제거효율을 평가하였다. 입자 제거 효율을 평가하기 위하여, 표준 형광입자(63nm/104nm 형광입자, Duke Scientifics, USA)를각각 IPA에 분산시킨 후, 실리콘 쿠폰 웨이퍼 ($20mm{\times}20mm$)를 일정시간 동안 Dipping 한 후, 고순도 질소로 건조시켜 오염하였다. 매엽식 세정장비(Aaron, Korea)에 1MHz와 2MHz의 콘-타입메가소닉 발진기 (Durasonic, Korea)를 각각 장착하였다.입자 오염 및 세정 후 입자 개수 측정 및 오염입자의 Mapping은 형광현미경 (LV100D, Nikon, Japan)과 소프트웨어(Image-proPlus, MediaCybernetics, USA)를 사용하여 평가하였으며, Hydrophone을 사용하여 메가소닉에서 발생되는 음압의 균일도를 각 조건에서 측정하였다. 각각의 세정공정은 1MHz와 2MHz 메가소닉 발진기 각각에서 1W, 3W, 5W 파워로 1분간 처리하였으며, 매질을 초순수를 사용하였다. 104nm 형광 입자는 1MHz 와 2 MHz 메가소닉 세정기와 모든 세정 공정조건에서 약 99%의 세정효율인 반면, 63nm 형광입자의 경우는 전체적인세정 결과가 80% 대로 감소하였다. 본 연구를 통하여, 입자크기의 미세화에 따른 입자제거효율이 크게 감소 하는 것을 확인할 수 있으며, 기존 Batch식 메가소닉 대비 단시간 및 낮은 전압에서 동일 혹은높은 세정 효율을 얻었다. 다만, 1MHz와 2MHz 메가소닉에서의 세정력은 큰 차이를 관찰 할 수 없었는데, 주파수변화에 따른 세정효율 측정을 위하여 미세 입자를 사용한 추가 실험이 필요 할 것이다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.1
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• pp.72-79
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• 2013

In wireless sensor networks, the selective wakeup scheme is one of the energy saving mechanisms, that is used for an object detecting or tracking. Recently, many protocols are proposed using the selective wakeup scheme for the continuous objects tracking such as forest fires and poison gas. They predict the future shape of continuous objects and activate only sensors in the predicted boundary area of the objects. It works correctly in a uniformly deployed wireless sensor networks. However, it cannot be directly applied to a randomly deployed sensor networks with voids. When the predicted area is in the void area, the activation message cannot reach and the predicted area cannot be activated at the right time. It leads to many detection errors for continuous object. Moreover, if a sensor is once foiled in a activation control then the next activation control might be continuously failed. The detection errors can be result in serious harm to people. In this paper, we propose a chaining selective wakeup scheme for robust continuous object tracking in wireless sensor networks. In our protocol, we collect the information of a void area during the network configuration time; if the next boundary area is in the void area, we activate the chained area surrounding the void area with activation control message.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.1
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• pp.79-84
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• 2007

Inventories of soluble elements in the gap and grain boundaries of domestic used PWR fuel pellets were measured to estimate the quantities of radionuclides that are liable to be rapidly released into the groundwater of a disposal site. The gap inventory of cesium for the pellets in the used fuel with a burn-up range of 45 to 66 GWD/MTU showed 0.85 to 1.7% of its total inventory, which was close to 1/6 to 1/3 of the fission gas release fraction (FGRF). However, the amounts of cesium released from the gaps of the pellets below 40 GWD/MTU of a burn-up and less than 1% FGRF were so erratic that the gap inventory could not be defined by ie FGRF. Strontium inventories in the gap and grain boundaries of the pellets in the same rod were not significantly varied, and the iodine inventory in the gap of the used PWR fuels was estimated to be less than or the same as the FGRF.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.2
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• pp.47-53
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• 2014

Three kinds of crystalline silicon have been used for the solar cell grade. First of all, single crystalline silicon is the main subject to enhance the production yield. Most of the efforts are focused on the control of the melt-crystal interface shape affected by the crystal-crucible rotation rate. The main subject in the multi-crystalline silicon ingot is the contamination control. Faster Ar gas flow above the melt surface will lower the carbon contamination in the crystal. And also, twin boundary electrically inactive is found to be more effective than grain boundary for the improvement of the MCLT. In the case of mono-like silicon material, propagation of the multi-crystalline silicon growing from the inner side crucible is the problem lowering the portion of the single crystalline part at the center of the ingot. Crystal growing apparatus giving higher cooling rate at the bottom and lower cooling rate at the side crucible was suggested as the optimum solution obtaining higher quality of the mono-like silicon ingot. Proper application of the seeds at the bottom of the crucible would be one of the solutions.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.3
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• pp.49-55
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• 2017

In this study, gas turbine engine inlet duct was designed to satisfy uniform flow at aerodynamic interface plane (AIP). Haack-series was selected as nose cone profile and duct outer radius($r_o$) was designed to satisfy to match with area change rate between the nose cone and outer duct wall by the 1-D sizing. The design object of the inlet duct wall profile which has the gradual area change rate was uniform Mach number in the core flow region and minimum boundary later thickness at the both inner nose wall and outer duct wall. The flow characteristics inside the inlet duct was evaluated using CFD. The static pressure distribution at the AIP showed uniform pattern within 0.16%. Based on Mach number profile, the boundary layer thickness was 2% of channel height. Kiel temperature rake location was decided less than 100 mm in front of nose cone where the Mach number is less than 0.1 in order to maximize the temperature probe recovery rate.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.107-112
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• 1999

The ZnSe/GaAs epilayers were grown by RF reactive sputtering. In order to obtain the optimum condition of the growth, we have studied the dependence of Ar pressure, input power of sputter, temperature of substrate, and the distande between substrate and target. Through the observation of the grown epilayer via electronic microscope, we confirmed that the layer's surface was uniform and the boundary of the substrate and the layer was well defined. The defotmation of lattice distortion and the distortion ratio were obtained by DCRC measurements. From mrasurements of photoluminescence, in the ZnSe/GaAs sample without injection of $N_2$gas, we found that the intensity of bound exciton $I_2$is stronger than that of $I_1$and the bound exiton $I_1$represents the deep acceptor level, $I_1\;^d$. On the other hand, in the ZnSe/GaAs sample with injection of$N_2$gas, the peak of$I_1$ was much higher than that of the $I_2$and the half width appeared to be narrow. We concluded that the p-type of ZnSe/GaAs epilayer was grown successfully, because of stronger peak of the bound exciton $I_1$due to the $N_2$dopping.