• Journal of Korean Society on Water Environment
• /
• v.23 no.5
• /
• pp.756-760
• /
• 2007

Most of the sewage treatment plants in Korea are being operated by using the conventional activated sludge process. Recently, as the water criteria have been strict with regard to such main culprits of eutrophication, the existing sewage treatment plants are obliged to upgrade their treatment technology to meet the criteria. Under such circumstances, this study was aimed at analyzing the conditions of an existing sewage treatment plants in Korea, and thereupon, test its treatment performance for the actual sewage water by operating a pilot plant. When the pilot plant was operated with the NPR process at the capacity of $30m^3/day$, the average contents of BOD, $COD_{Mn}$, SS, T-N and T-P in the effluents were 7.0 mg/L, 9.7 mg/L, 5.1 mg/L, 8.0 mg/L and 0.23 mg/L, respectively, which were very stable in general. Accordingly, if the NPR process used for this pilot plant to upgrade the treatment technology for the sewage treatment plat could be adopted, the effluent water quality criteria effective beginning from 2008 would be met.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.6
• /
• pp.1099-1103
• /
• 2007

TFT's have been intensively researched for possible electronic and display applications. Through tremendous engineering and scientific efforts, a-Si:H TFT fabrication process was greatly improved. In this paper, the reason on defects occurring at a-Si:H TFT fabrication process is analyzed and solved, so a-Si:H TFT's yield is increased and reliability is improved. The a-Si:H TFT of this paper is inverted staggered type TFT. The gate electrode is formed by patterning with length of $8{\mu}m{\sim}16{\mu}m$ and width of $80{\sim}200{\mu}m$ after depositing with gate electrode (Cr). We have fabricated a-SiN:H, conductor, etch-stopper and photo-resistor on gate electrode in sequence, respectively. We have deposited n+a-Si:H, NPR(Negative Photo Resister) layer after forming pattern of Cr gate electrode by etch-slower pattern. The NPR layer by inverting pattern of upper Sate electrode is patterned and the n+a-Si:H layer is etched by the NPR pattern. The NPR layer is removed. After Cr layer is deposited and patterned, the source-drain electrode is formed. The a-Si:H TFT made like this has problems at photo-lithography process caused by remains of PR. When sample is cleaned, this remains of PR makes thin chemical film on surface and damages device. Therefor, in order to improve this problem we added ashing process and cleaning process was enforced strictly. We can estimate that this method stabilizes fabrication process and makes to increase a-Si:H TFT's yield.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.7
• /
• pp.1393-1398
• /
• 2009

Conventionally, etching is first considered for microelectronics fabrication process and is specially important in process of a-Si:H thin film transistor for LCD. In this paper, we stabilize properties of device by development of wet and dry etching process. The a-Si:H TFTs of this paper is inverted staggered type. The gate electrode is lower part. The gate electrode is formed by patterning with length of 8 ${\mu}$m${\sim}$16 ${\mu}$m and width of 80${\sim}$200 ${\mu}$m after depositing with gate electrode (Cr) 1500 ${\AA}$under coming 7059 glass substrate. We have fabricated a-SiN:H, conductor, etch-stopper and photo resistor on gate electrode in sequence, respectively. The thickness of these thin films is formed with a-SiN:H (2000 ${\mu}$m), a-Si:H(2000 ${\mu}$m) and n+a-Si:H (500 ${\mu}$m), We have deposited n-a-Si:H, NPR(Negative Photo Resister) layer after forming pattern of Cr gate electrode by etch-stopper pattern. The NPR layer by inverting pattern of upper gate electrode is patterned and the n+a-Si:H layer is etched by the NPR pattern. The NPR layer is removed. After Cr layer is deposited and patterned, the source-drain electrode is formed. In the fabricated TFT, the most frequent problems are over and under etching in etching process. We were able to improve properties of device by strict criterion on wet, dry etching and cleaning process.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.5
• /
• pp.983-989
• /
• 2017

NADPH-P450 reductase (NPR) transfers electrons from NADPH to cytochrome P450 and heme oxygenase enzymes to support their catalytic activities. This protein is localized within the endoplasmic reticulum membrane and utilizes FMN, FAD, and NADPH as cofactors. Although NPR is essential toward enabling the biochemical and pharmacological analyses of P450 enzymes, its production as a recombinant purified protein requires a series of tedious efforts and a high cost due to the use of $NADP^+$ in the affinity chromatography process. In the present study, the rat NPR clone containing a $6{\times}$ Histidine-tag (NPR-His) was constructed and heterologously expressed. The NPR-His protein was purified using $Ni^{2+}$-affinity chromatography, and its functional features were characterized. A single band at 78 kDa was observed from SDS-PAGE and the purified protein displayed a maximum absorbance at 455 nm, indicating the presence of an oxidized flavin cofactor. Cytochrome c and nitroblue tetrazolium were reduced by purified NPR-His in an NADPH-dependent manner. The purified NPR-His successfully supported the catalytic activities of human P450 1A2 and 2A6 and fungal CYP52A21, yielding results similar to those obtained using conventional purified rat reductase. This study will facilitate the use of recombinant NPR-His protein in the various fields of P450 research.

• Steel and Composite Structures
• /
• v.49 no.4
• /
• pp.381-392
• /
• 2023

This study experimentally investigates the flexural behavior of steel-UHPC composite slabs composed of an innovative negative Poisson's ratio (NPR) steel plate and Ultra High Performance Concrete (UHPC) slab connected via demountable high-strength bolt shear connectors. Eight demountable composite slab specimens were fabricated and tested under traditional four-point bending method. The effects of loading histories (positive and negative bending moment), types of steel plate (NPR steel plate and Q355 steel plate) and spacings of high-strength bolts (150 mm, 200 mm and 250 mm) on the flexural behavior of demountable composite slab, including failure mode, load-deflection curve, interface relative slip, crack width and sectional strain distribution, were evaluated. The results revealed that under positive bending moment, the failure mode of composite slabs employing NPR steel plate was distinct from that with Q355 steel plate, which exhibited that part of high-strength bolts was cut off, part of pre-embedded padded extension nuts was pulled out, and UHPC collapsed due to instantaneous instability and etc. Besides, under the same spacing of high-strength bolts, NPR steel plate availably delayed and restrained the relative slip between steel plate and UHPC plate, thus significantly enhanced the cooperative deformation capacity, flexural stiffness and load capacity for composite slabs further. While under negative bending moment, NPR steel plate effectively improved the flexural capacity and deformation characteristics of composite slabs, but it has no obvious effect on the initial flexural stiffness of composite slabs. Meanwhile, the excellent crack-width control ability for UHPC endowed composite members with better durability. Furthermore, according to the sectional strain distribution analysis, due to the negative Poisson's ratio effect and high yield strength of NPR steel plate, the tensile strain between NPR steel plate and UHPC layer held strain compatibility during the whole loading process, and the magnitude of upward movement for sectional plastic neutral axis could be ignored with the increase of positive bending moment.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.43 no.11
• /
• pp.952-962
• /
• 2015

Various types of altitude compensation nozzles have been investigated to develop an effective propulsion system. In order to obtain baseline data for future study of dual bell nozzles, main characteristics and key parameters of dual bell nozzles are summarized and described by analysing DLR dual bell nozzles. DLR's experimental researches show that inflection angle is proportional to transition NPR, and extension length is proportional to side load, but inversely proportional to transition NPR and transition duration. Therefore, the nozzle geometry can be determined through the performance prediction process and thus the optimization process is required to meet performance requirements between parameters.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.06a
• /
• pp.507-509
• /
• 2007

본 연구는 기존의 방식으로 만든 비정질 실리콘 박막 트랜지스터의 제조공정에서 발생되는 결함에 대한 원인을 분석하고 해결함으로써 수율을 증대시키고 신뢰성을 개선하고자한다. 본 연구의 수소화 된 비정질 실리콘 박막 트랜지스터는 Inverted Staggered 형태로 게이트 전극이 하부에 있다. 실험 방법은 게이트전극, 절연층, 전도층, 에치스토퍼 및 포토레지스터층을 연속 증착한다. 스토퍼층을 게이트 전극의 패턴으로 남기고, 그 위에 $n^+a-Si:H$ 층 및 NPR(Negative Photo Resister)을 형성시킨다. 상부 게이트 전극과 반대의 패턴으로 NPR층을 패터닝하여 그것을 마스크로 상부 $n^+a-Si:H$ 층을 식각하고, 남아있는 NPR층을 제거한다. 그 위에 Cr층을 증착한 후 패터닝하여 소오스-드레인 전극을 위한 Cr층을 형성시켜 박막 트랜지스터를 제조한다. 이렇게 제조한 박막 트랜지스터에서 생기는 문제는 주로 광식각공정시 PR의 잔존이나 세척 시 얇은 화학막이 표면에 남거나 생겨서 발생되며, 이는 소자를 파괴시키는 주된 원인이 된다. 그러므로 이를 개선하기 위하여 ashing 이나 세척공정을 보다 엄격하게 수행하였다. 이와 같이 공정에 보다 엄격한 기준의 세척과 여분의 처리공정을 가하여 수율을 확실히 개선 할 수 있었다.

• Proceedings of the Korean Environmental Health Society Conference
• /
• 2004.06a
• /
• pp.155-159
• /
• 2004

We synthesized ion exchange resin that can remove $NO_3\;^-$ selectively rather than $SO_4\;^{2-}$. Ion exchange property of the synthesized ion exchange resin occurred like the following process, $NO_3\;^-$ > $SO_4\;^{2-}$, the efficiency of functional group to remove $NO_3\;^-$ occurred in the process of $NPr_3$ > $NBu_3$ > $NEt_3$ > $NMe_3$ > $NPe_3$ > $N(EtOH)_3$, and the efficiency of functional group to remove $SO_4\;^{2-}$ occurred in the process of $NMe_3$ > $NEt_3$ > $NPr_3$ > $NBu_3$ > $NPe_3$.

• Proceedings of the Korea Contents Association Conference
• /
• 2006.05a
• /
• pp.259-264
• /
• 2006

Some appearances of the result images from the researches on NPR(Non Photorealistic Rendering) look like contrary to the attributes of the real painting. As they are based on only the technical approach rather than the aesthetic and accurate analysis of the real painting which they modeled. Therefore the purpose of this paper is the abstraction of the exact features from the related real painting, the redefine of them applicable to the process, and the embodiment of the painterly NPR algorithms. This paper modeled the Impressionism which were originated in the France at the late nineteenth century. Accordingly, at first, I analyzed the general features of oil paintings and Impressionism paintings, and according to this analyses, I adjusted them to engineering elements(the direction, length, width, texture and speed of stroke, the edge and region of object, depth information and color etc) and programmed. I emphasize the importance and potentiality of the collaboration of artist and technician in the NPR research through the results in this paper.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2008.10a
• /
• pp.583-587
• /
• 2008

본 연구는 LCD 용 비정질 실리콘 박막 트랜지스터의 제조공정에서 가장 중요한 광 식각 공정을 중심으로 전체 공정을 개발하고, 공정의 안정성을 개선하여 소자의 신뢰성을 높이고자 한다. 본 연구의 수소화 된 비정질 실리콘 박막 트랜지스터는 Inverted Staggered 형태로 게이트 전극이 하부에 있다. 실험 방법은 게이트전극, 절연층, 전도층, 에치스토퍼 및 포토레지스터층을 연속 증착한다. 스토퍼층을 게이트 전극의 패턴으로 남기고, 그 위에 $n^+a-Si:H$ 층 및 NPR(Negative Photo Resister)을 형성시킨다. 상부 게이트 전극과 반대의 패턴으로 NPR층을 패터닝하여 그것을 마스크로 상부 $n^+a-Si:H$ 층을 식각하고, 남아있는 NPR층을 제거한다. 그 위에 Cr층을 증착한 후 패터닝하여 소오스-드레인 전극을 위한 Cr층을 형성시켜 박막 트랜지스터를 제조한다. 여기서 각 박막의 패터닝은 광 식각 공정으로 각 단위 박막의 특성에 맞는 광식각 공정이 필요하다. 제조한 박막 트랜지스터에서 가장 흔히 발생되는 문제는 주로 광식각공정시 발생하며, PR의 잔존이나 세척 시 얇은 화학막이 표면에 남거나 생겨서 발생되기도 하며, 이는 소자를 파괴시키는 주된 원인이 될 수 있다. 이와 같이 공정에 보다 엄격한 기준의 PR 패터닝, 박막의 식각 그리고 세척 등의 처리공정을 정밀하게 조절하여 소자의 특성을 확실히 개선 할 수 있었다.