• Korean Journal of Chemical Engineering
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• 제35권12호
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• pp.2394-2402
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• 2018

Textile dyes are some of the pollutants which have received the most attention because of the large volume of wastewater generated by the textile industry. Removal by means of adsorption is one of the most versatile alternatives to treat these effluents. Even though different adsorbents such as activated carbons and mineral materials have been proposed, polymeric adsorbents are a viable alternative. This work reports for the first time the use of polyelectrolyte PTZ and macroelectrolyte MTZ containing tetrazole groups as adsorbents useful in the textile dyes removal present in aqueous solutions and wastewater. Because of the anionic character of the tetrazole group, MTZ exhibits selective adsorption capabilities for cationic dyes of up to $156.25mg{\cdot}g^{-1}$. The kinetic study of the process of adsorption shows that PTZ and MTZ fit a pseudo second-order model. MTZ also shows utility as a flocculant agent in the treatment of wastewater containing dyes Indigo Blue and Reactive Black. The results showed that PTZ and MTZ may be used in the treatment of wastewater in a process of coagulation-flocculation followed by the treatment by adsorption. This two-stage treatment removed up to 95% of the dye present in the wastewater. As well as removing the dyes, the values for COD, suspended solids, pH, and color of the wastewater decreased, thus significantly improving its quality.

• 공업화학
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• 제22권3호
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• pp.308-311
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• 2011

하수슬러지 촤에 MnOx를 담지한 촉매를 사용하여 $NH_3$를 환원제로 하는 선택적 촉매 환원반응의 반응 메커니즘 분석을 수행하였다. XRD 분석 결과 활성 Mn phase는 $Mn_3O_4$인 것으로 여겨졌다. 또한 $150^{\circ}C$ 이하에서는 흡착반응이 주요한 질소산화물 저감 메커니즘으로 작동하였으나, $100{\sim}150^{\circ}C$에서는 환원반응도 질소산화물 저감에 관여하는 것으로 보여졌다. 실험결과에 기초하여 활성 촤와 여기에 MnOx를 담지한 촤에서의 반응속도상수를 비교하였다. MnOx 담지촤는 높은 충돌계수와 낮은 활성화 에너지에 기인하여 높은 반응속도 상수와 높은 NOx 제거 효율을 나타내었다. 두 가지 촤 모두 본 실험 조건하에서 활성화 에너지는 상대적으로 낮았다(10~12 kJ/mol).

• 한국산학기술학회논문지
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• 제13권11호
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• pp.5610-5614
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• 2012

암모니아를 환원제로 사용하는 선택적촉매환원법(Selective Catalytic Reduction, SCR)에서 촉매의 다양한 공정조건에서의 질소산화물 전환특성을 조사하였다. $H_2$-TPR을 통해 Mn, Cu가 포함된 탈질촉매의 경우 저온에서의 산소사용능력으로 우수함을 확인할 수 있었다. 탈질촉매 #1의 경우 반응온도가 증가함에 따라 탈질효율이 감소하나 탈질촉매 #2의 경우 반응온도가 증가함에 따라 탈질효율이 증가하다가 일정하였다. 이러한 현상은 두 촉매의 $NH_3$ 산화능력의 차이에 의한 것이다.

• 제어로봇시스템학회논문지
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• 제8권5호
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• pp.425-433
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• 2002

After the removal of SA (Selective Availability), horizontal accuracy of 25m(2dRMS) is easily obtained using GPS (Global Positioning System). In this paper, the error characteristics without SA are analyzed and a navigation algorithm concerns this error characteristics is proposed to further improve the accuracy. The proposed method utilizes the relationship between elevation angle and errors that are remained after ionospheric and troposheric delay compensation. The relationship is derived from real measurements and used as a weighting matrix of weighted least squares estimator. Furthermore, a RAIM (Receiver Autonomous Integrity Monitoring) technique is included to remove abnormal measurements affected by multi-path or low SNR (Signal-to-Noise Ratio). It is shown that using the proposed method, more than 4 times accurate result, which is comparable with DGPS (Differential GPS), can be obtained from experiments with real data. Besides accuracy and reliability, the proposed method reduces large jumps in position and maintains better performance than a method using mask angle to completely remove satellites below this mask angle. Thus it is expected that the proposed method can be efficiently applied to land navigation where some satellites are blocked by building or forest.

• BMB Reports
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• 제48권9호
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• pp.487-488
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• 2015

The ubiquitin-proteasome system and the autophagy lysosome system are the two major protein degradation machineries in eukaryotic cells. These two systems coordinate the removal of unwanted intracellular materials, but the mechanism by which they achieve this synchronization is largely unknown. The ubiquitination of substrates serves as a universal degradation signal for both systems. Our study revealed that the amino-terminal Arg, a canonical N-degron in the ubiquitin-proteasome system, also acts as a degradation signal in autophagy. We showed that many ER residents, such as BiP, contain evolutionally conserved arginylation permissive pro-N-degrons, and that certain inducers like dsDNA or proteasome inhibitors cause their translocation into the cytoplasm where they bind misfolded proteins and undergo amino-terminal arginylation by arginyl transferase 1 (ATE1). The amino-terminal Arg of BiP binds p62, which triggers p62 oligomerization and enhances p62-LC3 interaction, thereby stimulating autophagic delivery and degradation of misfolded proteins, promoting cell survival. This study reveals a novel ubiquitin-independent mechanism for the selective autophagy pathway, and provides an insight into how these two major protein degradation pathways communicate in cells to dispose the unwanted proteins. [BMB Reports 2015; 48(9): 487-488]

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.27.2-27.2
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• 2010

In recent years, there is a strong requirement of low cost, stable microelectro mechanical systems (MEMS) for resonators, microswitches and sensors. Most of these devices consist of freely suspended microcantilevers, which are usually made by the etching of some sacrificial materials. Herein, we have attempted to use Si nanowires, inherited from the parent Si wafer, as a sacrificial material due to its porosity, low cost and ease of fabrication. Prior to the fabrication of the Si nanowires silver nanoparticles were continuously formed on the surface of Si wafer. Vertically aligned Si nanowires were fabricated from the parent Si wafers by aqueous chemical route at $50^{\circ}C$. Afterwards, the morphological and structural characteristics of the Si nanowires were investigated. The morphology of nanowires was strongly modulated by the resistivity of the parent wafer. The 3-step etching of nanowires in diluted KOH solution was carried out at room temperature in order to control the fast etching. A layer of $Si_3N_4$ (300 nm) was used for the selective fabrication of nanowires. Finally, a freely suspended bridge of zinc oxide (ZnO) was fabricated after the removal of nanowires from the parent wafer. At present, we believe that this technique may provide a platform for the inexpensive fabrication of futuristic MEMS.

• 대한수의학회지
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• 제47권2호
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• pp.191-195
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• 2007

This study reveals the unusual case reported for the first time on the selective non digestion of yellow mealworm (Tenebrio molitor) larvae by arowana fish. In January 2005, an Asian arowana (Scleropages formosus) (red variety), from Daesang Tropical Fish Corporation, Seoul, Korea, mortality was observed due to unknown cause. No putative causal factors were suggested by bacteriological and parasitological examinations. Internal examination of the dissected stomach showed some undigested debris with mandible parts of mealworms attached to the mucosal lining of stomach wall. Feeding experiment of yellow mealworm (Tenebrio molitor) was conducted on the silver arowana (Osteoglossum bicirrhosum). Result showed that on the test group, fish released vomitous material containing undigested mandibles of mealworm was observed on the 24th day of the feeding experiment. Histopathological examination of the cross section of the stomach wall layers of the test groups, showed detached parts of the mucosal layer and gastric pits around the damaged area with intact mucularis tissues. While the control group fed with mealworm larvae without head part showed intact stomach wall layers consisting of gastric pit, mucosa and mucularis tissues. Fish on both treatments survived until the termination of experiment. The removal of mealworm larvae head before feeding probably help or aid in the fast digestion of these insect larvae.

• 한국입자에어로졸학회지
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• 제8권3호
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• pp.99-110
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• 2012

In the SCR (selective catalytic reduction) system which is used for controlling the NOx emission from the Diesel engines, the soot deposited on the catalysis causes degradation of the system performance. Numerical study was done to evaluate the performance of soot blower which is proposed as a method for removing the soot on the catalysis. The spray conditions and the effect of the compressed air from the AIG (air inlet gun) were analyzed numerically to evaluate the overall effective method of the soot blowing. The characteristics of the final velocity distribution and velocity waves across the inlet section of the catalysis were evaluated with respect to the geometries of the AIG outlets and pressure conditions. An experimental model was used to validate the results of the numerical calculation that is used for finding the effective removal blowing momentum transfer quantities of soot the inlet section of the catalysis, and it is proposed that the required minimum blowing momentum transfer quantities are over than 0.499 $kg/m{\bullet}t_{eff}$ in the current study.

• 한국전기전자재료학회논문지
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• 제29권6호
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• pp.370-375
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• 2016

In this paper, we investigated the electrical properties of crystalline silicon solar cell fabricated with Ni/Cu/Ag plating. The laser process was used to ablate silicon nitride layer as well as to form the selective emitter. Phosphoric acid layer was spin-coated to prevent damage caused by laser and formed selective emitter during laser process. As a result, the contact resistance was decreased by lower sheet resistance in electrode region. Low sheet resistance was obtained by increasing laser current, but efficiency and open circuit voltage were decreased by damage on the wafer surface. KOH treatment was used to remove the laser damage on the silicon surface prior to metalization of the front electrode by Ni/Cu/Ag plating. Ni and Cu were plated for each 4 minutes and 16 minutes and very thin layer of Ag with $1{\mu}m$ thickness was plated onto Ni/Cu electrode for 30 seconds to prevent oxidation of the electrode. The silicon solar cells with KOH treatment showed the 0.2% improved efficiency compared to those without treatment.

• 한국환경과학회지
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• 제30권6호
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• pp.501-505
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• 2021

V₂O₅-TiO₂ catalysts were prepared by various methods. V₂O₅-TiO₂ were prepared by sol-gel method with different drying conditions (aerogel and xerogel), and V₂O₅ supported on TiO₂ obtained by sol-gel method with precipitation-deposition method and impregnation method. The performance of the V₂O₅-TiO₂ catalysts was investigated for the selective oxidation of hydrogen sulfide in the stream containing both ammonia and excess water. All the catalysts showed good dispersion of vanadium and they had high H₂S conversion with no or little production of sulfur dioxide. The V₂O₅-TiO₂ aerogel catalyst prepared by sol-gel method with drying under super critical condition had the highest surface area which led to better catalytic activity compared to those by other synthesis methods.