• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.649-651
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• 2004

본 논문은 전역조명을 효율적으로 계산하기 위한 렌더링 방법인 photon mapping 에서 물체의 조명 값을 계산하는데 필요한 radiance를 구하는 새로운 방법을 제안한다. 기존의 방법은 포톤과 표면과의 반응 종류에 상관없이 포톤을 저장할 때 단지 위치와 기타 정보만을 저장하는 방법을 사용했었다. 본 논문에서는 각각의 포톤에 하나의 반지름을 부여하여 물체 표면과의 반응 종류에 따라 가변적으로 반지름을 조절하는 방법을 사용하였다. 구현 후 실험 결과 비슷한 렌러링 시간에 이전에 사용되던 방법에 비해서 caustic 과 그림자 표현에서 더 나은 이미지 품질을 보여주었다. 또한 이전 방법에서 caustic을 명확하게 표현하기 위해서 사용했던 caustic map을 사용한 경우에 비해서 더 빠르게 렌더링 되는 결과가 나타났다.

• Membrane Journal
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• v.27 no.1
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• pp.104-107
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• 2017

Among many methods in solving the organic contamination in the reverse osmosis operation, caustic soda (NaOH) wash method is efficient and commercially affordable. In continuation of our many organic pollution removal works, this study focused mainly on caustic soda wash with micro-bubble to removal the organic contamination of the spent membrane from reverse osmosis process. First, the membrane was forced the pollute using known organic pollutants such as Humic acid, Bovine serum albumin, Sodium alginate drug. The organic contamination on the membrane was monitored flux. The decontamination of organic contaminants was derived flux variation at individual caustic soda was injected micro-bubble methods and combined method as well. the found results explain removal of organic contaminants effective only by combined caustic soda wash with micro-bubble methods.

• Textile Coloration and Finishing
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• v.24 no.1
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• pp.45-53
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• 2012

In order to make a supermicrofiber fabric with PET/co-PET sea-island type filament fiber, the optimum conditions of dissolution of co-PET composite filament fiber was examined. The data set was made at various organic acid concentration and steam temperature with treated time as a main variable. At the same time, the microstructure changes by organic acid treatment of sea-island type PET supermicrofibers were monitored by thermal analysis morphology, DSC thermgrams and SEM images. Weight reduction behavior of supermicrofibers by caustic treatment was investigated in a comparative method. The termination of dissolution was also confirmed using DSC thermgrams and SEM images.

• Journal of Chest Surgery
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• v.32 no.6
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• pp.561-566
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• 1999

Background: It is not easy to surgically correct caustic pharyngeal strictures and a lot of effort is required to restore normal swallowing after the surgery. The authors reviewed the course in patients who underwent pharyngocolostomy. Material and Method: From August 1995 to March 1998, 6 patients with caustic stricture underwent esophageal reconstruction surgery. The time of injury to the replacement of the esophagus was from 3 months to 2 years and 4 months. The left colon was used in all patients. The surgical route was used under the sternum in 5 patients and through the esophageal hiatus in 1 patient. In the cervical anastomoses, the cervical pharyngocolic anastomosis was performed on the left pyriform sinus after a partial resection of the thyroid cartilage in 3 patients and on the posterolateral aspect of the inferior pharyngeal constrictor in 3 patients. Result: Postoperative complications consisted of a dysphagia in 3 patients and left vocal cord palsy in 1 patient. There was no cervical anastomotic stricture. Revisional procedures consisted of an esophageal dilation and free jejunal graft in 1 patient, supraglottic scar band resection in 1 patient, and colonic mucosal resection in 1 patient. Swallowing training was required in the 3 patients with dysphagia. Restoration of normal swallowing was obtained in all patients between the 9th and the 303rd day. Conclusion: Pharyngocolostomy is a satisfactory method of treatment for patients with intractable caustic stricture. Pharyngocolojejunostomy is an effective alternative for esophagocologastrostomy in cases where gastric outlets are involved.

• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1783-1789
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• 2005

Modeling of a steam generator crevice in a nuclear power system needs to take into account both thermalhydraulic and chemical phenomena. As a first step towards developing a reliable model, a chemical equilibrium model was developed to predict chemical speciation in a magnetite-packed crevice by adopting the “tableau” method. The model was benchmarked with the available experimental data and the maximum deviation did not exceed two orders of magnitude. The developed model was applied to predict the chemical speciation in a magnetite-packed crevice. It was predicted that caustic environment was developed by the concentration of NaOH and the dissolution of magnetite. The model indicated that the dominant aqueous species of iron in the caustic crevice was $FeO_2\;^-$. The increase of electrochemical corrosion potential observed in the experiment was rationalized by the decrease of dissolved hydrogen concentration due to a boiling process. It was predicted that under the deaerated condition magnetite was oxidized to hematite.

• Resources Recycling
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• v.21 no.2
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• pp.41-46
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• 2012

An investigation on the recovery of nickel from spent electroless plating solutions has been performed using the electrowinning method. For this aim, nickel in spent electroless plating solutions was separated as nickel hydroxide through the addition of caustic soda. Nickel hydroxide was completely dissolved with sulfuric acid and an electrolysis was performed for electrowinning of nickel from nickel solutions. As a result, it was found that more than 99% of nickel in spent electroless plating solutions could be precipitated as nickel hydroxide above pH 10 with the addition of caustic soda. As far as the current efficiency in electrowinning of nickel was concerned, it was decreased with increase in the current density.

• Journal of the Korean Ceramic Society
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• v.24 no.2
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• pp.186-192
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• 1987

ZrO2 powders having high purity were prepared from domestic zircon sand using the caustic fusion method and the soda ash sintering process. In the caustic fusion method, ZrO2 recovery was reached to 96% when 100/140 mesh zircon was reacted with NaOH at the NaOH/Zircon mole ratio 6 and at 650$^{\circ}C$ for 2 hours. And in the soda ash sintering process, ZrO2 was recovered to 88.5% when -325 mesh zircon was reacted with Na2CO3 at the Na2CO3/Zircon mole ratio 1.1 and 1050$^{\circ}C$ for 2 hours. In both cases, Zr component was extracted to ZrOCl2, subsequently crystallized to ZrOCl2$.$8H2O to increase the purity, and converted to ZrO2 by precipitation. And to increase the sinter ability of powder, Cl- ion was removed and strong agglomeration was avoided by methanol distribution of Zr(OH)4 precipitates.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.1
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• pp.118-131
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• 1995

The shock fracture analysis for the structures of navy vessels subject to underwater explosions or of high speed vessels frequently subject to impact loads has been carried out in two steps such as the global or macro analysis and the fine or micro analysis. In the macro analysis, Doubly Asymptotic Approximation(DAA) has been applied. The three main failure modes of structure members subject to strong shock loading are late time fracture mode such as plastic large deformation mainly due to dynamic plastic buckling, and the early time fracture mode such as tensile tearing failure or transverse shear failure. In this paper, the tensile tearing failure mode is numerically analyzed for the micro analysis by calculating the dynamic stress intensity factor $K_I(t)$, which shows the relation between stress wave and crack propagation on the longitudinal stiffener of the model. Especially, in calculating this factor, the numerical caustic method developed from shadow optical method of caustic well known as experimental method is used. The fully submerged vessel is adopted for the macro analysis at first, of which the longitudinal stiffener, subject to early shock pressure time history calculated in macro analysis, is adopted for the micro analysis.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.4
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• pp.307-317
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• 1993

The problem of sea wave transformation in the coastal zone taking into account effects of nonlinearity and disperison has been studied. Mathematical model for description of regular wave transformation is based on the method of nonlinear ray theory. The equations for rays and wave field have been produced. Nonlinear wave field is described by the modified Korteweg-de Vries equation. Some analytical solutions of this equation are obtained. Caustic transformation and dissipation effects are included in the mathematical model. Numerical algorithm of solution of the Korteweg-de Vries equation and its stability criterion are described. Results of nonlinear transformation of sea waves in the coastal zone are demonstrated.

• Journal of Chest Surgery
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• v.29 no.4
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• pp.420-426
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• 1996

We previously reported 344 cases of esophageal reconstruction for caustic esophageal stricture between 1959 and 1982, and this is the second report of 69 cases during 12 year period from Jan. 1983 to Feb. 1995. There were 32 males and 37 females, ranging in age from 4 to 65 years(mean 36.4 years). Caustic materials were acid in 37 (53.7%) and alkali in 31 (44.9%). All cases underwent colon interposition without esophageal resection except 3 cases of cancer complication which were resected through thoracotomy. In 64 cases isoperistaltic right colon with teminal ileum interposition were performed, and 5 cases were interposed with left colon either isoperistaltic (2 cases) or antiperistaltic (3 cases) method. Anastomotic leakage was the most frequently encountered c mplication (14.4%, 10 cases), and they were 11.6%(8 cases) from cervical, 2.8% (2 cases) from ileocolostoma. Overall operative mortality was 2.9% (2169), main causes of death were sepsis due to graft necrosis and mediastinitis. During 6 months to 12years (mean 2.Syears) follow-up of survived 67 cases, 88.1% (59 cases) ate normally, 7.5% (5 cases) complained of moderate dysphagia (eating liquid diet), and 4.5% (3 cases) were unable to eat by mouth. In our experience, reconstruction of the esphagus with the colon is a satisfactory method that can be accomplished with acceptable morbidity and mortality. The right colon is a durable and functional esophageal substitute.