하수처리 : UV/H2o2 공정을 이용한 Trichloroethylene 산화에 nitrate가 미치는 영향

문태훈 ( Tae Hoon Moon ),박재한 ( Jea Han Park ),안윤희 ( Yoon Hee Ahn ),박찬규 ( Chan Kyu Park ),최보경 ( Bo Kyung Choi ),윤영한 ( Young H. Yoon ),안창효 ( Chang Hyo Ahn ),고광백 ( Kwang Baik Ko ) 한국물환경학회 ( 구 한국수질보전학회 ) 2007 공동 추계학술발표회 Vol.2007 No.-

하수처리 : UV/H2O2 공정을 이용한 Trichloroethylene 산화에 nitrate가 미치는 영향

문태훈 ( Tae Hoon Moon ),박재한 ( Jea Han Park ),안윤희 ( Yoon Hee Ahn ),박찬규 ( Chan Kyu Park ),최보경 ( Bo Kyung Choi ),윤영한 ( Young H. Yoon ),안창효 ( Chang Hyo Ahn ),고광백 ( Kwang Baik Ko ) 대한상하수도학회 2007 공동추계 학술발표회 논문집 Vol.2007 No.-

자유곡면 가공공정의 정형화된 모델링

김대현,김보현,편영식,최병규 한국 CAD/CAM학회 1998 한국CDE학회 논문집 Vol.3 No.3

분석 투과전자현미경을 이용 ZnO바리스터의 계면을 관찰하였다. 바리스터 특성의 조성물에서 Bi_(2)O_(3) 의 함량을 바꾸어 바리스터를 제조하여 이들의 전기적 특성을 측정하였고 또한 입계구조와 전기적 특성과의 관련성을 규명하기 위해 입계에 대해 분석 투과전자현미경을 이용 입계를 관찰하였다. 전기적 특성의 변화는 Bi_(2)O_(3) 의 함량 변화에 민감하였으나 입계구조의 변화에서는 분석 범위내에서 변화를 관 찰 할 수 없었다. Even though most die-maker are using CAD/CAM systems for NC tool-path generation, "frontend" CAD/CAM technologies have not been fully adapted to sculptured surface machining(SSM) nor are sufficiently utilized in die shops. This gap between die-making industry and CAD/CAM community persists mainly because of the lack of a SSM-process model through which the two groups communicate with each other. Proposed in this paper is a model of SSM-processes which is built around the concepts of machining stages, unit machining operations, and each machining stage is decomposed into a sequence of unit machining operations(UMOs). Identified in the paper are five machining stages and 17 types of UMO. Based on the framework of the proposed model, an example of inner-panel stamping-die machining processes is described in detail.

Dipole-Coil-Based Wide-Range Inductive Power Transfer Systems for Wireless Sensors

Choi, Bo H.,Thai, V. X.,Lee, Eun S.,Kim, Ji H.,Rim, Chun T. IEEE 2016 IEEE transactions on industrial electronics Vol.63 No.5

<P>A dipole-coil-based extremely loosely coupled inductive power transfer system (IPTS) for wireless sensors over a wide range is proposed. The overall superiority of dipole coils for a long-distance power delivery over loop coils with an identical configuration of a square core is verified by comparing the magnetizing inductance between primary and secondary coils. Series-parallel resonant circuits were used to achieve a higher load voltage than that of the series-series scheme. Contrary to conventional IPTSs or coupled magnetic resonance systems, the quality factor Q was set as low as 100, guaranteeing a frequency tolerance of 1%, where a prototype of narrow dipole coils with a length of 2 m was used to deliver 10.3 W of power up to 7 m away at a low frequency of 20 kHz. The powering capabilities of the proposed IPTS were experimentally compared inside and outside of a metal container 8 m x 4 m x 2.5 m in size at different frequencies ranging from 20 to 150 kHz, where the proposed IPTS is highly likely to be surrounded by arbitrary distributed conductors in most wireless sensor usage environments. The coupling coefficient. between the primary and secondary coils was measured over a long distance from 2 to 12 m for different secondary coil positions, where. is mostly much less than 0.01. A comparative analysis of the maximum amounts of load power among different core materials, i.e., two ferrite cores and an amorphous core, was conducted in relation to the design of a secondary coil. The results were verified by experiments at a given switching frequency of 20 kHz.</P>

A Novel Single-SiC-Switch-Based ZVZCS Tapped Boost Converter

Choi, Bo H.,Lee, Sung W.,Thai, V. X.,Rim, Chun T. IEEE 2014 IEEE transactions on power electronics Vol.29 No.10

<P>A new single-active-switch-based zero voltage and zero current switching (ZVZCS) tapped boost converter is proposed. For the ZVZCS operation of the converter, three diodes and two capacitors were added to an ordinary tapped boost converter. When turned ON, the active switch is in zero current switching with the help of leakage inductance of a tapped inductor. When turned OFF, the energy of the leakage inductance is transferred to a snubber capacitor through a diode, which results in zero voltage switching of the active switch. Then the energy of the snubber capacitor is retrieved by a recovery capacitor connected to the tapped inductor. Different from most conventional soft switching converters that need at least two active switches, the proposed converter requires only one active switch such as JFET and MOSFET to guarantee ZVZCS operation for wide operating ranges of duty cycle, load current, and input voltage. The voltage stress of the active switch is always less than the load voltage, and soft switching turn-on and off is achieved without cumbersome current or voltage sensing, which could not be obtained from quasi-resonant converters that also have an active switch. Furthermore, the dc voltage gain of the proposed converter is quite robust against load change and is determined only by duty cycle like a canonical boost converter; hence, it can be even open-loop controlled. All the diodes are in ZVZCS as well, and all the components except an output diode have the voltage stress less than the load voltage. In this paper, the voltage stress of the output diode was selected to have two times the load voltage. A detailed analysis for the continuous conduction mode and the design procedures of the proposed converter is fully established, and experimentally verified for a 450-W prototype over the input voltage of 100-250 V, achieving 98.1% of maximum efficiency at the switching frequency of 100 kHz with a SiC JFET. Due to its versatile soft switching characteristics, the proposed scheme can be generally applied to high-frequency and high-efficiency dc-dc converters as well as power factor correctors.</P>

Six Degrees of Freedom Mobile Inductive Power Transfer by Crossed Dipole Tx and Rx Coils

Choi, Bo H.,Lee, Eun S.,Sohn, Yeong H.,Jang, Gi C.,Rim, Chun T. IEEE 2016 IEEE TRANSACTIONS ON POWER ELECTRONICS - Vol.31 No.4

<P>Crossed dipole coils for the wide-range 3-D omnidirectional inductive power transfer (IPT) are proposed. Free positioning of a plane receiving (Rx) coil is obtained for an arbitrary direction within 1m from a plane transmission (Tx) coil. Both the Tx and Rx coils consists of crossed dipole coils with an orthogonal phase difference; hence, a rotating magnetic field is generated from the Tx, which enables the Rx to receive power vertically or horizontally. Thus, the 3-D omnidirectional IPT is first realized for both the plate type Tx and Rx coils, which is crucial for practical applications, where volumetric coil structure is highly prohibited. This optimized configuration of coils has been obtained through a general classification of power transfer and searching for mathematical constraints on multi-D omnidirectional IPT. Conventional loop coils are thoroughly analyzed, and verified to be inadequate for the plate-type omnidirectional IPT in this paper. Simulation-based design of the proposed crossed dipole coils for a uniform magnetic field distribution is provided, and the 3-D omnidirectional IPT is experimentally verified by prototype Rx coils for a wireless power-zone of 1 m(3) with a prototype Tx coil of 1 m(2) at an operating frequency of 280 kHz, meeting the power matters alliance. The maximum overall efficiency was 33.6% when the input power was 100 W.</P>

Lumped Impedance Transformers for Compact and Robust Coupled Magnetic Resonance Systems

Choi, Bo H.,Lee, Eun S.,Jin Huh,Rim, Chun T. Institute of Electrical and Electronics Engineers 2015 IEEE transactions on power electronics Vol. No.

<P>An innovative coupled magnetic resonance system (CMRS), introducing two lumped impedance transformers, is proposed. There are three major magnetic couplings between coils in CMRS: source-transmitter (Tx), Tx-receiver (Rx), and Rx-load couplings. Except for Tx-Rx coupling, other couplings do not directly contribute to wireless power transfer. Hence, in this paper, this miscellaneous coupling is replaced with a lumped transformer with ferrite core. Because there is only a Tx-Rx coupling, the CMRS becomes compact in size and robust to ambient changes. Moreover, the design of CMRS is drastically simplified without complicated multiresonance tunings due to little magnetic flux linkage from the source coil or load coil. Coreless coils are used for Tx and Rx coils to examine the characteristics of CMRS with lumped transformers. A detailed static analysis on the explicit circuit model of the proposed CMRS and design procedures are fully established. Experiments for 1- and 10-W prototype CMRSs with a class-E inverter at the switching frequency of 500 kHz, where the quality factors are less than 100, verified the usefulness of the proposed model, achieving 80% of the maximum Tx coil-to-load efficiency. It is concluded in this paper that the conventional CMRS, in general, is just a special form of an inductive power transfer system where the quality factor is extremely high.</P>

DCM Analysis of Single-Switch-Based ZVZCS Converters With a Tapped Inductor

Choi, Bo H.,Lee, Eun S.,Kim, Ji H.,Rim, Chun T. IEEE 2015 IEEE TRANSACTIONS ON POWER ELECTRONICS - Vol.30 No.12

<P>The analysis of a novel single-active-switch-based zero voltage and zero current switching (ZVZCS) tapped boost converter in the discontinuous conduction mode (DCM) is proposed in this paper. The ZVZCS converter includes a lossless snubber composed of three diodes and two capacitors and exhibits novel ZVZCS operation for wide operating ranges of duty cycles, load currents, and input voltages. The voltage stress of the active switch is always less than the load voltage, and soft switching turn-on and turn-off are achieved without cumbersome current or voltage sensing, which could not have been obtained from quasi-resonant converters that also have an active switch. Detailed analyses of the DCM and the component stresses of the proposed converter are presented. Experiments for a 450-W prototype exhibited 99.0% of the maximum efficiency with a SiC JFET at the switching frequency of 50 kHz, and the ZVZCS operation is guaranteed, even for the DCM under the experimental conditions. Moreover, the proposed ZVZCS principle has been applied to a tapped buck-boost converter case, which was also experimentally verified.</P>

7m 원격 무선전력전송 개발 사례

최보환(Bo H. Choi),이은수(Eun S. Lee),김지훈(Ji H. Kim),임춘택(Chun T. Rim) 전력전자학회 2014 전력전자학술대회 논문집 Vol.2014 No.7

Leigh 증후군에서 생화학적 효소분석과 자기공명 분광검사(MR Spectroscopy)의 유용성에 관한 고찰

최보화(Bo Hwa Choi),김정호(Jeong Ho Kim),김현미(Hyun Mee Kim),최충곤(Choong Kon Choi),유한욱(Han Wook Yoo),고태성(Tae Sung Ko),Brian H. Robinson 대한소아신경학회 1998 대한소아신경학회지 Vol.5 No.2

목적 : Leigh 증후군은 lactate의 병적인 형성이 특징인 사립체성 질환으로서 뇌간, 뇌저 신경절, 시상, 소뇌 및 척수를 침범하여 여러 가지 다양한 임상증상을 나타내며 생화학적으로는 사립체내의 에너지 대사과정 중 pyruvate dehydrogenase complex 결핍, cytochrome c oxidase(complex Ⅳ) 결핍 등 여러 가지 효소의 결함에 의해서 초래될 수 있다. 이 질환은 괴사성 병변의 조직학적 소견으로 확진할 수 있으나, 특징적인 병변의 방사선학적 소견과 임상증상, 다른 질환을 배제함으로써 가능해졌다. 최근에는 생화학적 검사에 의한 효소의 결핍과 MR spectroscopy의 이용으로 좀더 정확한 진단에 도움을 주고 있다. 이에 저자들은 Leigh 증후군으로 진단된 환아에서 생화학적 효소분석과 MRS를 시행하여 이들의 유용성을 알아보고자 본 연구를 시행하였다. 방법 : 1992년 7월부터 1997년 6월까지 서울중앙병원 소아과에 입원하여 임상증상과 MRI 검사에서 Leigh 증후군으로 진단된 8명을 대상으로, 생화학적 효소분석(7명)은 섬유아 세포 배양후 캐나다의 Toronto 대학에 의뢰하였고, MRS는 본원에서 시행하여 각각 분석하였으며, 동시에 시행한 뇌척수액과 혈청에서의 lactate치, lactate/pyruvate률과 각각 비교하였다. 결과 : 1) 진단시 나이는 7개월에서 8년 11개월이었며, 남아가 7명 여아가 1명이었다. 2) 임상증성은 경련 6례(75%), 호흡 곤란, 안증상, 근긴장성 저하가 각각 4례(50%), 발달지연과 의식변화가 각각 3례(38%), 지능저하가 2례(25%) 등의 순으로 있었다. 3) MRI상 병변은 모두 양측에서 보였고, 부위별로는 피각 6례(75%), 미상핵 5례(63%), 연수 4례(50%), 흑질, 시상에서 각각 3례(38%) 등으로 보였다. 4)뇌척수액과 혈청에서 lactate치, lactate/pyruvate률이 증가한 2례에서는 생화학적 효소분석에서 NADH-coenzyme Q reductase(complex Ⅰ), cytochrome C oxidase(complex Ⅳ) 결핍을 각각 보였다. 5) 뇌척수액과 혈청에서 lactate치, lactate/pyruvate률이 정상인 6례에서는 발병후 4개월 이내에 시행한 MRS에서 전례에서 lactate 증가, NAA peak 감소를 보였다. 결론 : 생화학적 효소분석과 MRS Leigh 증후군에 있어서 진단적 가치가 매우 클 것으로 생각되며, 특히 MRS는 급성기 병의 활동성 판단에 도움을 줄 것으로 여겨진다. Purpose : Leigh syndrome is a kind of mitochondrial disease with a pathological production of lactate and variable clinical manifestations. Recently biochemical assay of the mitochondrial enzyme activity and MRS are becoming a powerful tool for the definitive antemorterm diagnosis of this disease. The aim of this study was designed to determine the usefulness of biochemical enzyme assay and MRS in Leigh syndrome. Methods : A clinical study of 8 cases of pediatric patients were diagnosed as Leigh syndrome on the basis of clinical manifestations and MRI features at the department of pediatrics, Ulsan university hospital, from July, 1992 to June, 1997. Biochemical enzyme assay of the cultured skin fibroblasts was consulted to hospital for sick children, Toronto, Canada. Cerebral lactates were detected on MRS were analysed in relation to the MRI findings and lactate levels in the CSF. Result : 1) Age at diagnosis ranged from 7 months to 8.9 years; seven were boys and one was girl. 2) Main clinical symptoms were as follows in the order of frequency; seizure(75%), ophthalmoplegia(50%), hemiplegia(50%), hypotonia(50%), respiratory difficulty(50%), developmental delay(38%), consciousness change(38%), mental retardation(25%). 3) Anatomical locations of the focal lesions detected on the initial MRI were as follows in the order of frequency; putamen(75%), caudate nuclei(63%), medulla oblongata(4/8, 50%), substantia nigra(38%), thalamus(38%). 4) Biochemical enzyme assay revealed deficiency of NADH cytochrome c reductase(complex Ⅰ) and dificiency of cytochrome c oxidase(complex Ⅳ) respectively in 2 patients who had markedly elevated serum and CSF lactate levels and lactate/pyruvate ratio 5) Cerebral lactates were detected by MRS from 6 lesions of 1 week-4 months old in 6 patients who had normal or mildly elevated serum and CSF lactate levels and lactate/pvruvate ratio. Conclusion : MRS detected the brain parenchymal lactate non-invasively from the acute or subacute lesions. Therefore, combined evaluation by MRS and biochemical enzyme assay will provide an important information for the diagnosis and estimation of disease activity in pediatric patients who are suspected to have Leigh syndrome.