• Clean Technology
• /
• v.11 no.1
• /
• pp.21-28
• /
• 2005

Nitric acid free pickling solution was applied to solve the severe environmental problems attributed to nitric acid during pickling process of stainless steel product. In points of pickling capability and erosion of stainless steel base metal, a solution contains I% of hydrochloric acid and 2% of hydrofluoric acid and hydrogen peroxide was revealed as the best alternative to conventional mixed acid of nitric acid and hydrofluoric acid. To keep the pickling capability, it was necessary to maintain the concentration ratio of hydrogen peroxide to hydrochloric acid above 0.5.

• The Journal of the Korea Contents Association
• /
• v.8 no.10
• /
• pp.129-141
• /
• 2008

Comprehensive real estate taxes needs to be improved so that it performs its intended functions by realizing fair taxation and stabilizing the price of real estate, and ultimately attains social justice in Korea. This study analyzed the current state of comprehensive real estate taxes through a questionnaire survey, and the results are summarized as follows. First, in the analysis of people's perception on the adequacy of the tax rate of comprehensive real estate taxes, those who owned a house worthy of 600 million won or a higher value as an object of real estate tax perceived the adequacy of the tax rate more negatively than those who owned a house of less than 600 million won. The same result was observed for comprehensive real estate taxes on lands. Second, in the analysis of the contribution of comprehensive real estate taxes to the accomplishment of policies, the respondents showed a high frequency of positive replies to some of policies related to comprehensive real estate taxes.

• 주택과사람들
• /
• s.192
• /
• pp.86-88
• /
• 2006

강남에 사는 사람들은 '세금 폭탄'을 맞았다. '우리가 봉이냐'며 불만 가득한 표정이 역력하다. 올해는 종합부동산세가 2배 가까이 늘어날 예정이어서 강남에 집을 소유한 사람들은 애간장을 태우고 있다. 강남 일대 아파트 시장의 반응과 시세 동향 그리고 몇몇 아파트의 종합 부동산세와 보유세를 직접 계산해보면서 납부할 세액이 어느 정도 될지 살펴보자.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2012.05a
• /
• pp.327-327
• /
• 2012

Si 함량이 증가할 수록 산화Scale에 Si 산화물층이 응집하여 전체적인 산세 속도를 저하시키는 경향이 있는 것을 알려져있다. 본 연구에서는 Si 함량에 따라서 산화물 산세 거동을 실험적을 파악하고자 하였다.

• Resources Recycling
• /
• v.26 no.5
• /
• pp.97-104
• /
• 2017

Nuclear fuel cladding tubes are manufactured through pilgering and the annealing process. In order to remove the oxidized layer and impurities on the surface of the tube, a pickling process is required. Zirconium (Zr) is dissolved in a HF and $HNO_3$ acid mixture during the process and the pickling waste acid, including the dissolved Zr, is completely discarded after neutralization. This study observes the effects of the residual impurities (Ba) in the pickling solution regenerated from the $BaF_2$ precipitation process on the waste pickling solution. In addition, the concentration of Ba and Zr for the actual nuclear fuel cladding tube process was optimized. The regenerated pickling solution was tested through a pilot plant pickling process device that simulates the commercial pickling process of nuclear fuel cladding tubes, and the pickling efficiency was analyzed through AFM analysis of the roughness of the cladding tube surface.

• Clean Technology
• /
• v.2 no.1
• /
• pp.96-108
• /
• 1996

$NO_x$ is mainly emitted from mixed acid pickling process in the stainless industry and its impact to the environment has been worried over. This study which may be considered as one of the development of clean technologies, differing from the traditional end pipe technology is about how to reduce $NO_x$ emission through the modification of corresponding process. This study consists of two parts. First, the influence of various reaction parameters in a acid pickling process on $NO_x$ emission was investigated. Second, the influence of hydrogen peroxide on $NO_x$ formation, which is known as inhibitor of $NO_x$ emission, was investigated. Major findings in this study are as follows. The important reaction parameters which have a great influence on $NO_x$ emission are the reaction temperature and the concentration of fluoric acid. The concentration of nitric acid, some of which results in $NO_x$ compound is not as important as the concentration of fluoric acid. Synthetic mixed acid of nitric acid and fluoric acid itself in absent of pickling plate contributed the $NO_x$ emission, however, its impact was negligible in terms of quantity. The addition of hydrogen peroxide to the acid pickling process significantly contributed to the reduction of $NO_x$ emission and successfully achieved 80% reduction of $NO_x$ emission at the condition of $9.51{\times}10^{-2}mole\;hydrogen\;peroxide/m^2$ pickling area. This result was compared to literature value from Avesta steel process, indicating a sixth of hydrogen peroxide addition of Avesta's in achieving a same amount of $NO_x$ reduction. The region of the economic hydrogen peroxide addition per unit area of plate to be pickled from the result of this study was established.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 1999.05a
• /
• pp.65-66
• /
• 1999

• Clean Technology
• /
• v.20 no.3
• /
• pp.226-231
• /
• 2014

This study presents a micromolding for the synthesis of Janus particles with reconfigurable shape by pH stimuli. First, we use acrylic acid (AA) as pH responsive monomer in the hydrophilic part and trimethylolpropane triacylate (TMPTA) in the hydrophobic part, respectively. The change of acidity in solvent induces the swelling of hydrophilic part in the Janus particles. The pH-responsive Janus particles show different swelling ratio of hydrophilic part in according to composition of acrylic acid in diverse range (0-70% v/v) and pH (3-11). As the concentration of acrylic acid in the hydrophilic part and environmental pH increase, the hydrophilic part in the Janus particles is proportionally swelled. Second, we fabricate novel type of Janus particles with two different hydrophilicities. As a proof of concept, we have applied acrylic acid (AA) and 2-(dimethylamino)ethyl methacrylate (DAEMA) into each part because the monomers provide reverse responsive activity. As expected, these Janus particles show different shape anisotropies with reconfigurable property in accordance with the polarity of each part at same acidity of environmental solvent. We envision that the stimuli responsive Janus particles have a wide application from fundamental science to diagnostic apparatus.

• Resources Recycling
• /
• v.20 no.1
• /
• pp.61-68
• /
• 2011

Impurity removal from metallurgical grade silicon by acid washing at $50^{\circ}C$ was investigated by employing sulfuric, nitric acid and the mixture of hydrochloric and hydrofluoric acid. Acid washing treatment had no effect on the removal of boron and the concentration of this clement after treatment was rather increased. In our experimental range, the removal percentage of phosphorus was 60%. In the acid washing with sulfuric and nitric acid, the removal percentage of major impurities was below 50%, which indicates that refining effect was not great with these acids. Acid washing with the mixture of hydrochloric and hydrofluoric acid led to removal percentage of higher than 90%. Data on the purity of silicon after acid washing at various conditions are reported.

• Proceedings of the Korean Statistical Society Conference
• /
• 2002.05a
• /
• pp.113-118
• /
• 2002

본 논문에서는 한글 문자의 세리프(serif) 계열과 산세리프(sans-serif) 계열의 분류를 위한 특징을 제안한다. 한글의 서체는 세로획의 시작 부분에 장식 세리프(돌기)가 있는 세리프 계열과 그렇지 않은 산세리프 계열로 나눌 수 있다. 제안하는 한글 문자의 서체 분류 방법은 세리프 형태에서 추출한 특징을 이용하여 세리프 또는 산세리프 클래스로 분류하고, 각 클래스별로 적합한 특징 및 분류기를 학습하여 보다 다양한 서체를 인식하도록 계층적으로 설계한다. 제안한 특징의 유용성을 입증하기 위한 실험은 명조, 바탕, 궁서, 고딕, 돋움, 굴림 서체의 3,000개 낱자 영상에 적용하였다.