• 한국세라믹학회지
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• 제42권3호
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• pp.188-192
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• 2005

무기 고분자인 polycarbosilane(PCS)으로부터 탄화규소 (SiC) 세라믹스로의 전환을 열산화에 의한 불융화 처리를 한 후 열분해 하는 공정과 불응화 처리를 하지 않고 열분해 하는 두 공정으로 각각 행하고, 수율 및 산소 함량을 비교하였다. 또한 두 공정으로 얻어진 SiC 세라믹스의 고온 안정성 평가를 위해 진공분위기의 고온에서 열처리 하여 무게 감량을 비교하였다. 열산화에 의한 불융화 처리를 한 후 열분해 하여 얻어진 SiC 세라믹스의 수율이 불융화 처리를 하지 않고 열분해 하여 얻어진 SiC세라믹스의 수율보다 높게 나타났으나, 이를 고온의 진공분위기에서 열처리 하였을 때는 열산화에 의해 불융화 처리를 한 공정으로부터 얻어진 SiC 세라믹스의 무게 감량이 크게 나타났다.

• International Journal of Internet, Broadcasting and Communication
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• 제9권2호
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• pp.20-26
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• 2017

Process control is crucial in many industries, especially in semiconductor manufacturing. In such large-volume multistage manufacturing systems, a product has to go through a very large number of processing steps with reentrant) before being completed. This manufacturing system has many machines of different types for processing a high mix of products. Each process step has specific quality standards and most of them have nonlinear dynamics due to physical and/or chemical reactions. Moreover, many of the processing steps suffer from drift or disturbance. To assure high stability and yield, on-line quality monitoring of the wafers is required. In this paper we develop a real-time fault detection system on semiconductor manufacturing process. Proposed system is superior to other incremental fault detection system and shows similar performance compared to batch way.

• 한국전기전자재료학회논문지
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• 제14권3호
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• pp.223-227
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• 2001

In this paper, the authors present the fabrication of high-yield Si thin-membranes by electrochemical etch-stop in tetramethyl ammonium hydroxide (TMAH): isopropyl alcohol (IPA):pyrazine solutions. The current-voltage (I-V) characteristics of n- and p-type Si in TMAH:IPA;pyrazine solutions were analysed, repsectively. Open circuit potential (OCP)and passivation potential (PP) of n- and p-type Si, respectively, were obtained and applied potential was selected between n- and p-type Si PPs. The electrochemical etch-stop method was applied to the fabrication of 801 micro-membranes with 20.0 $\mu\textrm{m}$ thickness on a 5" Si wafer. The average thickness of fabricated 801 micro-membranes on one wafer 20.03$\mu\textrm{m}$ and the standard deviation was ${\pm}$0.26$\mu\textrm{m}$. The Si surface of the etch-stopped micro-membranes was extremely flat with no noticeable taper or nonuniformity. The results indicate that use of the electrochemical etch-stop method for the etching of Si in TMAH:IPA;pyrazine solutions provides a powerful and versatile alternative process for fabricating high-yield Si micro-membranes.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1265-1268
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• 2005

Due to the increase of the need for reliable high density information storage devices, the demand for precise machining of the slider in HDD is rapidly growing. The present fabrication process of slider bears some serious problems such as low yield ratio in mass production, which is mainly caused by inefficient machining processes in shaping camber and crown on the slider. In order to increase slider yield ratio in HDD, a new systematic machining process is proposed and developed in this work. This new machining process includes the use of magnetorheological (MR) fluid, a smart polishing material generally used for ultra-fine surface finishing of micro structures. It is shown that the process proposed in this work enables to make camber and crown pattern in the scale of few tens of nanometers. Experiment results shows that the MR polishing can be also used for shaping process of micro structures.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.251.1-251.1
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• 2013

Combination of oxidative vacuum annealing and oxygen plasma treatment can serve as a simple and efficient method of line-width modification of imprinted nanopatterns. Since the vacuum annealing and oxygen plasma could lead mass loss of polymeric materials, either one of the process can yield a narrowed patterns. However, the vacuum annealing process usually demands quite high temperatures (${\geq}300^{\circ}C$) and extended annealing time to get appreciable line-width reduction. Although the plasma treatment may be considered as an effective low temperature rapid process for the line-width reduction, it is also suffering for the lowered controllability on application to very fine patterns. We have found that the vacuum annealing temperature can be lowered by introducing the oxygen in the vacuum process and that the combination of oxygen plasma treatment with the vacuum annealing could yield the best result in the line-with reduction of the imprinted polymeric nanopatterns. Well-defined line width reduction by more than 50% was successfully demonstrated at relatively low temperatures. Furthermore, it was verified that this process was applicable to the nanopatterns of different shapes and materials.

• 한국기계가공학회지
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• 제21권1호
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• pp.49-55
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• 2022

Recently, the automobile industry has continued to demand lighter materials owing to international environmental regulations and increased convenience. To address this demand, aluminum parts have increased in popularity and are mainly developed and produced through hot forging and cold pressing. However, because this method has low yield and low production efficiency, a new manufacturing method is desirable. In this study, the water capacity efficiency of an aluminum inner tie rod socket was investigated using cold forging that provided a high yield and excellent production efficiency. Mechanical properties were derived through tensile testing of 6110A aluminum materials, and critical fracture factor and process analysis based on experimental data were carried out. The optimized process was applied as a prototype using cold multi-stage forging, and based on the derived results, the formability, productivity, and material efficiency of aluminum inner tie rod socket parts using this cold forging process was verified.

• KSBB Journal
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• 제25권4호
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• pp.357-362
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• 2010

Green alga, Ulva pertusa kjelmann has been known to be one of the largest pollutants in Korea. Therefore, the efficient pretreatment processes have been required to improve the yields of fermentable sugar. The optimal pretreatment conditions were determined to be $195^{\circ}C$ for 15 min. The sugar yield of glucose and xylose were estimated as 20.5%, and 5.0% respectively, based on theoretical yields. However solid residues were estimated enzymatic digestibility of 90-95% with cellulase loading of 15 FPU/g glucan. This process was proved to generate the low concentration of Hydroxy-Methyl-Furfural (51 ppm), which resulted in ethanol production with 95% of the maximum conversion yield from glucose in the culture of Saccharomyces cerevisiae (ATCC, 24858). This study showed that Ulva pertusa kjellmann can be used as a bioetahnol resource using the high temperature liquefaction process.

• KSBB Journal
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• 제15권4호
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• pp.346-351
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• 2000

식물세포 배양액으로부터 회수한 식불세포 내 수분 함 량에 따른 추출효율은 건조 정도 보다는 건조방법 에 상당 히 영향을 받음을 알 수 있었으며 건조하여 추출할 경우 사용되는 추출용매를 절약할 수 있었다. 여러가지 유기용 매를 이용하여 paclitaxe1의 추출 경향을 조사한 결과 메탄올의 경우 가장 적 은 양으로 가장 높은 paclitaxe1 회 수율을 얻어 가장 효과적임을 알 수 있었다. 추출방법의 경우 counter-current 형태를 사용할 경우 batch형태에 비하여 용 매 사용량을 줄일 수 있으며 paclitaxe1 회수율은 거의 차이가 없음을 알 수 있었다. Batch 형태를 이용한 메탄올 추출시 식불세포의 경우 4회 (회수율>99%), 식불세포조각의 경우 1회 (회수융>96%)의 추출로 대부분의 paclitaxe1 회수가 가능 하였다. 또한 메탄올 추출시 90% 이상의 머탄올 농도이변 충분하며 (회수율>98%), 추출시biomass와 메탄올 의 흔합비 (Kg biomass: L MeOH)는 1: 1, 추출시간은 1회 5분 이상이면 적당 하였다. 메탄올 추출불에 포함된 극성불 순물들은 다음 공정 인 액/액 (methylene chloride/ MeOH)추 출로 제거하여 정제공정에 사용되어 진다.

• Korean Chemical Engineering Research
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• 제52권5호
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• pp.587-591
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• 2014

고급 홍삼의 생산 수율을 증가시키는 제어 방법에 관한 실험을 수행하였다. 수삼에서 홍삼을 만드는 과정 중 수증기로 수삼을 찌는 증삼 공정에서 동체균열, 내공, 내백 등이 발생하는데 이는 홍삼의 품질을 저하시키는 원인이 된다. 고급 홍삼의 수율을 증가시키기 위해서는 이런 불량 요인을 최소화하는 방법이 필요하다. 최근까지 대부분의 증삼 공정의 제어는 증삼 과정의 필수 인자인 온도만을 조절하거나 온도와 압력을 동시에 조절하여 제어하는 방법이 연구되었다. 그러나 이는 불량 요인을 최소화하는 목적에 적합하지 못한 것으로 보인다. 이와 달리, 본 연구에서는 기존의 홍삼 제조 방식을 토대로 $96{\sim}99^{\circ}C$의 온도를 유지하면서 수삼의 무게 제어를 통하여 불량 요인을 최소화하는 제어 방법을 제시한다. 무게 제어를 적용한 실험 결과 증삼 과정 후 수삼의 동체균열의 불량요인이 줄어드는 것을 확인할 수 있었다.

• 한국환경과학회지
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• 제4권3호
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• pp.259-267
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• 1995

This study was conducted to evaluate the effects of pressure and dissolved oxygen concentration on the activated slut비e and to determine the optimum depth of deep shaft process. Some results from this study were summarized as follows. 1. It is considered that low sludge product in the activated sludge system maintaining high dissolved oxygen concentration is attributed to the increase of endogeneous respiration rate caused by the increase of aerobic zone in the sludge floe. 2. The increase of dissolved oxygen concentration does not affect to the increase of organic removal efficiency greatly and therefore the limiting factor is the substrate transfer into the inner part of floe. 3. The yield coefficient, Y is decreased in proportion to the increase of oxygen concentration. In this study, Y values arre ranged from 0.70 to 0.41 according to the variation of dissolved oxygen concentration from 18.0mg/$\ell$ to 258 mg/$\ell$. 4. The optimum depth of deep shaft process should be determined within the limits of non-toxicity to the microorganism and it is about loom in this study.