• Journal of Power System Engineering
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• 제7권3호
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• pp.12-17
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• 2003

The purpose of this study is to observe the purification characteristics of NOx, CO and HC in various catalysts and excess air ratio conditions. For this purpose, we installed various catalysts on the back stream of the coaxial diffusion burner with swirler. As the result, in the case of NOx, Pt-Rh catalyst shows very high value that is more than 90%-conversion efficiency without the relation with the excess air ratio. After excess air ratio of ${\alpha}=1.14$, it shows that the conversion efficiencies were more than 80% in the every Pt catalyst in the view of conversion of every exhaust with changing of the excess air ratio.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제57권8호
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• pp.1464-1469
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• 2008

A CMOS Gm-C filter with variable cutoff frequency applicable for using in the direct conversion receiver is designed. The designed filter comprises the CMOS differential transconductors, and the gm of the transconductor is controlled by the bias voltage. This configuration can compensate variant of the cutoff frequency which could be generated by external noises, and also be used in multiband receiver. As a results of HSPICE simulation, the control range of the cutoff frequency is $1.5MHz{\sim}3.5MHz$ and the gain control range is $-2.8dB{\sim}2.6dB$. The layout of the designed 5th-order Elliptic low-pass filter is performed to fabricate a chip using $2.5V-0.25{\mu}m$ CMOS processing parameter.

• Transactions of the Korean Society of Mechanical Engineers
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• 제12권3호
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• pp.466-472
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• 1988

An algorithm and its computer program were developed for the computer aided automatic conversion from 2-D design drawing, which includes arbitrary curves, to a 3-D object, and the 3-D object obtained from the developed program was used to generate the tool path of NC milling machine. The algorithm and its computer program developed were applied to several real objects for their feasibility check and showed satisfactory results. Therefore, it was proved that the algorithm and its program developed can be applied to the CAM for the mechanical parts having arbitraily curved shapes by automatically generating its 3-D object. As a result of this study a basic theory for the integration of CAD/CAM was established which will prompt the improved quality and productivity.

• Archives of Pharmacal Research
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• 제22권3호
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• pp.249-254
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• 1999

Enzymatic conversion of brain glycosylphosphatidylinositol-linked alkaline phosphatase (GPI-AP), amphiphilic, was examined. When GPI-AP was incubated with glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD), a negligible conversion of GPI-AP to hydrophilic form was observed. The inclusion of monoacylglycerols enhanced the enzymatic conversion, although the action of monoacylglycerols differed greatly according to the size of acyl group; the enzymatic conversion was enhanced considerably in the presence of monoacylglycerols possessing acyl group of longer chain length ($C_{10-}C_{18}$), which monoacylglycerols with acyl moiety of shorter length ($C_{4-}C_{8}$) did fail to augment the enzymatic conversion. Noteworthy, monooleoylglycerol was much more effective than the other monoacylglycerols in promoting the enzymatic conversion, indicating a beneficial role of the unsaturation in acyl chain. Meanwhile, ionic amphiphiles such as monohexadecyllysophosphatidylcholoine and palmitoyl-carnitine decreased the enzymatic conversion of GPI-AP in a concentration-dependent manner, with monohexadecyllysophosphatidylcholine and palmitoyl-carnitine deceased the enzymatic conversion of GPI-AP in a concentration-dependent manner, with monohexadecyllysophosphatidylcholoine being more inhibitory than palmitoylcarnitine. Separately when GPI-AP was exposed to various oxidants prior to the incubation with GPI-PLD, a remarkable decrease of the enzymatic conversion was observed with hypochlorite and peroynitrite generators, but not $H_{2}O_{2}$. In further study, hypochlorite was found to inactivate GPI-PLD at low concentrations ($3~100{\mu}M$). From these results, it is suggested that the enzymatic conversion of GPI-AP by GPI-PLD may be regulated in vivo system.

• Journal of the Korea Computer Graphics Society
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• 제3권2호
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• pp.77-84
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• 1997

Solid modeling refers to techniques for unambiguous representations of three- dimensional objects. The most widely used techniques for solid modeling have been Constructive Solid Geometry (CSG) and Boundary Representation (BRep). Contemporary solid modeling systems typically support both representations, and bilateral conversions between CSG and BRep are essential. However, computing a CSG from a BRep is largely an open problem. This paper presents 3D geometric reasoning algorithms for converting a BRep into a special CSG, called Destructive Solid Geometry (DSG) whose Boolean operations are all subtractions. The major application area of BRep-to-DSG conversion is feature recognition, which is essential for integrating CAD and CAM.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.89-92
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• 2008

CMOS 기반의 고주파 집적회로에서는 높은 이득과 출력을 얻기 위하여 인덕터와 같은 수동소자를 사용한다. 그러나 수동소자를 사용하게 되면 넓은 면적을 차지하기 때문에 회로의 크기를 증가시키는 단점을 갖는다. 본 논문에서는 PMOS 를 기반으로 구현한 active inductor 를 적용하여 회로의 면적을 줄일 수 있으며, 기존의 주파수 변환기와 동등한 선형 특성을 갖는 상향 주파수 변환기를 설계하였다. 인덕터를 적용한 상향 주파수 변환기의 OIP3 ($3^{rd}$ Output Intercept Point)는 1.3 dBm 을 가지며, 제안한 상향 주파수 변환기의 OIP3 는 0.8 dBm 으로 동등한 선형 특성을 보이며, layout 상에서 회로의 면적을 40 % 이상 감소하는 특성의 선형 송신기용 주파수 변환기를 설계 분석하였다.

• Journal of the Institute of Electronics and Information Engineers
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• 제50권11호
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• pp.64-69
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• 2013

In this paper, a high-speed CMOS Image Sensor (CIS) based on a 10-bit two-step single-slope A/D converter is proposed. The A/D converter is composed of both a 5-bit coarse ADC and a 6-bit fine ADC, and the conversion speed is 10 times faster than that of the single-slope A/D converter. In order to have a small noise characteristics, further, a Digital Correlated Double Sampling(D-CDS) is also discussed. The proposed A/D converter has been fabricated with 0.13um 1-poly 4-metal CIS process, and it has a QVGA($320{\times}240$) resolution. The fabricated chip size is $5mm{\times}3mm$, and the power consumption is about 35mW at 3.3V supply voltage. The measured conversion speed is 10us, and the frame rate is 220 frames/s.

• Land and Housing Review
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• 제13권3호
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• pp.115-123
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• 2022

Recently, the adoption of BIM technology in domestic civil engineering projects has continually increased both in its numbers and scope. However, the BIM model was developed and used after the 2D design was developed instead of creating the BIM model from the conceptual design phase. BIM must be used throughout every phase of design and construction to use BIM for its original purpose. However, if BIM application is applied in heavy civil projects without a step-by-step guideline, it can confuse the market and face industry resistance to using BIM. Therefore, BIM is currently being used step by step in the civil engineering field by using BIM as a conversion design. However, the BIM conversion design method, currently being performed in the Preliminary design stage, has many difficulties due to low work efficiency. This paper analyzes the existing process of converting a 2D design into a 3D BIM model while addressing the issues related to its low work efficiency. To this end, a novel approach to 2D to BIM conversion for the design development stage is proposed.

• BMB Reports
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• 제32권5호
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• pp.480-485
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• 1999

Tyrosine phenol-lyase of thermophilic Symbiobacterium sp. SC-1, which is obligately and symbiotically dependent on thermophilic Bacillus sp. SK-1, was purified and characterized. The enzyme is composed of four identical subunits and contains approximately 1 mol of pyridoxal 5'-phosphate (PLP) per mol subunit as a cofactor. The enzyme showed absorption maxima at 330 and 420 nm, and lost this absorption profile by treatment with phenylhydrazine. The apparent dissociation constsnt, $K'_D$, for PLP was determined with the apoenzyme to be about $1.2\;{\mu}M$. The isoelectric point was 4.9. The optimal temperature and pH for the $\alpha,\beta$-elimination of L-tyrosine were found to be $80^{\circ}C$ and pH 8.0, respectively. The substrate specificity of the enzyme was very broad: L-amino acids including L-tyrosine, 3,4-dihydroxyphenyl-L-alanine (L-DOPA), L-cysteine, L-serine, S-methyl-L-cysteine, $\beta$-chloro-L-alanine, and S-(o-nitrophenyl)-L-cysteine all served as substrates. D-Tyrosine and D-serine were also decomposed into pyruvic acid and ammonia at rates of 7% and 31% relative to their corresponding L-enantiomers, respectively. D-Alanine, which was inert as a substrate in a, $\beta$-elimination, was the only D-amino acid racemized by the enzyme. The $K_m$ values for L-tyrosine, L-DOPA, S-(o-nitrophenyl)-L-cysteine, $\beta$-chloro-L-alanine, and S-methyl-L-cysteine were 0.19, 9.9, 0.36, 12, and 5.5 mM, respectively.

• JSTS:Journal of Semiconductor Technology and Science
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• 제3권2호
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• pp.89-95
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• 2003

In this paper, we have designed and fabricated high conversion gain Q-band active sub-harmonic mixers for a receiver of millimeter wave wireless communication systems. The fabricated active sub-harmonic mixer uses 2nd harmonic signals of a low local oscillator (LO) frequency. The fabricated mixer was successfully integrated by using $0.1{\;}\mu\textrm{m}$GaAs pseudomorphic high electron mobility transistors (PHEMTs) and coplanar waveguide (CPW) structures. From the measurement, it shows that maximum conversion gain of 4.8 dB has obtained at a RF frequency of 40 GHz for 10 dBm LO power of 17.5 GHz. Conversion gain from the fabricated sub-harmonic mixer is one of the best reported thus far. And a phase noise of the 2nd harmonic was obtained -90.23 dBc/Hz at 100 kHz offset. The active sub-harmonic mixer also ensure a high degree of isolations, which are -35.8 dB from LO-to-IF and -40.5 dB from LO-to-RF, respectively, at a LO frequency of 17.5 GHz.