물리교육에서 엔트로피 개념의 도입방법

문정혁,강영봉,박규은 濟州大學校 師範大學 科學敎育硏究所 1994 科學敎育 Vol.11 No.1

The difficulties involved in teaching the concept of entropy in the form of Clausius, which is the common practice in physics education today, are dicussed and, as an alternative to this, the concept of entropy in the form of Boltzamnn, which is using the number of quantum state, is suggested. This form of entropy is shown to be not only nearer to the core of the concept, but also much easier to grasp and more apt to stimulate the student's interest. A few examples, ie, the laws of Thermodynamics, and equation of state of an ideal gas, are included in order to show the fruitfulness and very gen-eral application of this relation.

A High-Density 64k-Bit One-Time Programmable ROM Array with 3-Transistor Cell Standard CMOS Gate-Oxide Antifuse

Hyouk-Kyu Cha,Jinbong Kim,Kwyro Lee 대한전자공학회 2004 Journal of semiconductor technology and science Vol.4 No.2

A high-density 3-transistor cell (me-time programmable (OTP) ROM array using standard CMOS Gate-Oxide antifuse (AF) is proposed, fabricated, and characterized with 0.18um CMOS process. The proposed non-volatile high-density OTP ROM is composed of an array of 3-T OTP cells with the 3-T consisting of an nMOS AF, a high voltage (HV) blocking transistor, and a cell access transistor, all compatible with standard CMOS technology.

A 13.56 MHz CMOS Multi-Stage Rectifier for Wireless Power Transfer in Biomedical Applications

Hyouk-Kyu Cha(차혁규) 대한전자공학회 2013 전자공학회논문지 Vol.50 No.3

0.18-μm CMOS 반도체 공정을 이용하여 신체에 깊이 이식되어 있는 deep implant 의료 전자기기에서의 무선전력전달을 위한 고효율의 다단 정류기 (multi-stage rectifier)를 구현하였다. 세 개의 단계로 이루어진 정류기는 cross-coupled 된 구조를 이용하여 외부에서 전달되는 작은 AC 입력 신호를 boost하여 1.2-1.5 V의 DC 출력 신호를 implant 전자기기로 전달한다. 설계 된 정류기는 13.56 MHz에서 0.6-Vpp의 작은 RF 입력 신호와 10-kΩ의 load 저항이 연결 된 측정 환경에서 최대 70 %의 전력 변환 효율을 달성하였다. An efficient multi-stage rectifier for wireless power transfer in deep implant medical devices is implemented using 0.18-μm CMOS technology. The presented three-stage rectifier employs a cross-coupled topology to boost a small input AC signal from the external device to produce a 1.2-1.5 V output DC signal for the implant device. The designed rectifier achieves a maximum measured power conversion efficiency of 70% at 13.56 MHz under the conditions of a low 0.6-Vpp RF input signal with a 10-kΩ output load resistance.

초음파 의료 영상 시스템을 위한 재구성 가능한 아날로그 집적회로

차혁규(Hyouk-Kyu Cha) 대한전자공학회 2014 전자공학회논문지 Vol.51 No.12

본 논문에서는 초음파 의료 영상 시스템을 위한 아날로그 front-end 집적회로를 0.18-㎛ 표준 CMOS 반도체 공정을 이용하여 설계하였다. 제안 된 front-end 회로는 2.6 ㎒에서 15-V 고전압 펄스 신호를 생성하는 송신부와 고전압 차단 스위치 및 저전력 저잡음 증폭기에 해당하는 수신부를 모두 포함하고 있으며, 동작 모드에 따라서 송신부의 출력 드라이버를 수신단의 스위치 회로로 재구성이 가능하도록 설계를 하여 기존 front-end 회로와 비교하였을 때 한 채널 당 70% 이상의 칩 면적을 줄일 수 있다. 설계 된 단일 채널 front-end회로는 0.045 ㎟ 이하의 작은 칩 면적을 차지함으로써 다중 어레이 방식의 초음파 의료 영상 시스템에 적용 시 작은 면적으로 구현이 가능하다. This paper presents an analog front-end integrated circuit (IC) for medical ultrasound imaging systems using standard 0.18-㎛ CMOS process. The proposed front-end circuit includes the transmit part which consists of 15-V high-voltage pulser operating at 2.6 ㎒, and the receive part which consists of switch and a low-power low-noise preamplifier. Depending on the operation mode, the output driver in the transmit pulser can be reconfigured as the switch in the receive path and thus the area of the overall front-end IC is reduced by over 70% in comparison to previous work. The designed single-channel front-end prototype consumes less than 0.045 ㎟ of core area and can be utilized as a key building block in highly-integrated multi-array ultrasound medical imaging systems.

A High-Density 64k-Bit One-Time Programmable ROM Array with 3-Transistor Cell Standard CMOS Gate-Oxide Antifuse

Cha, Hyouk-Kyu,Kim, Jin-Bong,Lee, Kwy-Ro The Institute of Electronics and Information Engin 2004 Journal of semiconductor technology and science Vol.4 No.2

A high-density 3-transistor cell one-time programmable (OTP) ROM array using standard CMOS Gate-Oxide antifuse (AF) is proposed, fabricated, and characterized with $0.18{\mu}m$ CMOS process. The proposed non-volatile high-density OTP ROM is composed of an array of 3-T OTP cells with the 3-T consisting of an nMOS AF, a high voltage (HV) blocking transistor, and a cell access transistor, all compatible with standard CMOS technology.

체내 이식 신경 신호 기록 장치를 위한 저전압 저전력 아날로그 Front-End 집적회로

차혁규(Hyouk-Kyu Cha) 대한전자공학회 2016 전자공학회논문지 Vol.53 No.10

본 논문에서는 체내 이식용 신경 신호 기록 장치를 위한 저전압 저전력 아날로그 front-end 집적회로를 설계하였다. 제안된 집적 회로는 1 Hz에서 5 kHz 주파수 대역에 존재하는 신경 신호를 처리하기 위해 저잡음 neural 증폭기와 대역폭 조절이 가능한 능동 bandpass 필터로 구성되어 있다. Neural 증폭기는 우수한 잡음 특성을 위해 source-degenerated folded-cascode 연산증폭기를 기반으로 하여 설계하였고, 능동 필터의 경우 저전력의 current-mirror 연산증폭기를 이용하여 설계하였다. 능동필터의 high-pass cutoff 주파수는 1 Hz에서 300 Hz까지 제어가 가능하며, low-pass cutoff 주파수는 300 Hz에서 8 kHz까지 제어가 가능하다. 전체 아날로그 front-end 회로는 53.1 dB의 전압 이득 성능과 1 Hz에서 10 kHz 대역에 대해서 4.68 μVrms의 입력 잡음 성능과 3.67의 noise efficiency factor 성능을 보인다. 0.18-μm CMOS 공정을 이용하여 설계를 하였고 1-V 전원에서 3.2 μW의 전력 소모 성능을 갖는다. 칩 레이아웃 면적은 0.19 mm² 이다. A low-voltage, low-power analog front-end IC for neural recording implant devices is presented. The proposed IC consists of a low-noise neural amplifier and a programmable active bandpass filter to process neural signals residing in the band of 1 Hz to 5 kHz. The neural amplifier is based on a source-degenerated folded-cascode operational transconductance amplifier (OTA) for good noise performance while the following bandpass filter utilizes a low-power current-mirror based OTA with programmable high-pass cutoff frequencies from 1 Hz to 300 Hz and low-pass cutoff frequencies from 300 Hz to 8 kHz. The total recording analog front-end provides 53.1 dB of voltage gain, 4.68 μVrms of integrated input referred noise within 1 Hz to 10 kHz, and noise efficiency factor of 3.67. The IC is designed using 0.18-μm CMOS process and consumes a total of 3.2 μW at 1-V supply voltage. The layout area of the IC is 0.19 mm².

두경부에 발생한 원발성 피부암의 임상적 고찰

이혁진(Hyouk Jin Lee),오성수(Sung Soo Oh),박윤규(Yoon Kyu Park),정을삼(Eul Sam Chung) 대한두경부종양학회 1994 대한두경부 종양학회지 Vol.10 No.2

Authors reviewed 73 cases of primary skin cancer arising from head and neck, including comparative clinical data of 63 cases of squamous cell carcinoma and basal cell carcinoma retrospectively. There was no significant sexual predilection in each type of cancer and 77% of all cases were occurred after age of 50. The data of occurring site and occupation(farmer; 41%) implied that sunlight exposure strongly concerned in development of skin cancer. Comparing the data of 63 cases of squamous cell carcinoma and basal cell carcinoma, authors found out no remarkable difference in mean diameter of primary lesion at first visit of clinic, but some difference in mean duration, the percentage of the cases less than 1 year­duration and percentage of T1 lesion with no statistical significance(p>0.05). Combination of surgery and radiotherapy had relatively lower recurrence rate (11%) than surgery alone (13%). Squamous cell carcinoma had higher recurrence rate(34%) and metastasis rate(28%) than basal cell carcinoma; 6% and 3%, respectively(p<0.05).

데이터 중심의 국방 시뮬레이션 네트워크 미들웨어에 관한 연구

이규호 ( Kyu-ho Lee ),심준용 ( Jun-yong Shim ),위성혁 ( Soung-hyouk Wi ),김세환 ( Sae-hwan Kim ) 한국정보처리학회 2014 한국정보처리학회 학술대회논문집 Vol.21 No.2

국방 시뮬레이션 소프트웨어 개발 시 급변하는 요구사항과 반복적인 구현에 빠르게 대처하기 위해 플러그인 기반의 개발프레임워크가 사용되어왔다. 그러나 개발된 소프트웨어는 내부 컴포넌트의 재활 용성은 증대되었으나,수많은 노드가 연결되는 분산 시뮬레이션 환경에는 적합하지 못했다. 이에 기존의 개발된 데이터 모델인 NOM을 기반으로 객체 간 통신이 가능하고,분산 환경에서 노드의 확장이 유연한 통신 미들웨어인 «Comm+를 제안한다.

A standard CMOS high-voltage transmitter for ultrasound medical imaging applications

Taylor Francis 2014 International Journal of Electronics Vol.101 No.3

The parallel growth of motoneuron axons with the dorsal aorta depends on Vegfc/Vegfr3 signaling in zebrafish

Kwon, Hyouk-Bum,Fukuhara, Shigetomo,Asakawa, Kazuhide,Ando, Koji,Kashiwada, Takeru,Kawakami, Koichi,Hibi, Masahiko,Kwon, Young-Guen,Kim, Kyu-Won,Alitalo, Kari,Mochizuki, Naoki Company of Biologists 2013 Development Vol.140 No.19

<P>Blood vessels and neurons grow often side by side. However, the molecular and cellular mechanisms underlying their parallel development remain unclear. Here, we report that a subpopulation of secondary motoneurons extends axons ventrally outside of the neural tubes and rostrocaudally as a fascicle beneath the dorsal aorta (DA) in zebrafish. We tried to clarify the mechanism by which these motoneuron axons grow beneath the DA and found that Vegfc in the DA and Vegfr3 in the motoneurons were essential for the axon growth. Forced expression of either Vegfc in arteries or Vegfr3 in motoneurons resulted in enhanced axon growth of motoneurons over the DA. Both <I>vegfr3</I> morphants and <I>vegfc</I> morphants lost the alignment of motoneuron axons with DA. In addition, forced expression of two mutant forms of Vegfr3 in motoneurons, potentially trapping endogenous Vegfc, resulted in failure of growth of motoneuron axons beneath the DA. Finally, a <I>vegfr3</I> mutant fish lacked the motoneuron axons beneath the DA. Collectively, Vegfc from the preformed DA guides the axon growth of secondary motoneurons.</P>