A terahertz performance of hybrid single walled CNT based amplifier with analytical approach

Kumar, Sandeep,Song, Hanjung Elsevier 2018 Solid-state electronics Vol.139 No.-

<P><B>Abstract</B></P> <P>This work is focuses on terahertz performance of hybrid single walled carbon nanotube (CNT) based amplifier and proposed for measurement of soil parameters application. The proposed circuit topology provides hybrid structure which achieves wide impedance bandwidth of 0.33 THz within range of 1.07-THz to 1.42-THz with fractional amount of 28%. The single walled RF CNT network executes proposed ambition and proves its ability to resonant at 1.25-THz with analytical approach. Moreover, a RF based microstrip transmission line radiator used as compensator in the circuit topology which achieves more than 30 dB of gain. A proper methodology is chosen for achieves stability at circuit level in order to obtain desired optimal conditions. The fundamental approach optimizes matched impedance condition at (50+j0) Ω and noise variation with impact of series resistances for the proposed hybrid circuit topology and demonstrates the accuracy of performance parameters at the circuit level. The chip fabrication of the proposed circuit by using RF based commercial CMOS process of 45 nm which reveals promising results with simulation one. Additionally, power measurement analysis achieves highest output power of 26 dBm with power added efficiency of 78%. The succeed minimum noise figure from 0.6 dB to 0.4 dB is outstanding achievement for circuit topology at terahertz range. The chip area of hybrid circuit is 0.65 mm<SUP>2</SUP> and power consumption of 9.6 mW.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hybrid CNT based amplifier performance at terahertz. </LI> <LI> To achieved wide impedance bandwidth up to 0.33-THz. </LI> <LI> Proposed circuit occupies less chip area. </LI> <LI> Noise figure of 0.4 dB is outstanding achievements. </LI> <LI> Power Measurement reveals highest PAE of 78%. </LI> </UL> </P>

Effects of Thickness and Multi-Walled Carbon Nanotube Incorporation on the Performance of Nafion Membrane-Based Ionic Polymer-Metal Composite Actuators

Park, Minjeong,Kim, Joohee,Song, Hanjung,Kim, Seonpil,Jeon, Minhyon American Scientific Publishers 2018 Nanoscience and Nanotechnology Letters Vol.10 No.8

Ag/TiO₂ NPs/TiO₂ TF/Si Based Non-Volatile Memristor Device for Neuromorphic Computing Applications

Chakrabartty, Shubhro,Kumar, Sandeep,Song, Hanjung,Jeon, Minhyon American Scientific Publishers 2018 Journal of nanoscience and nanotechnology Vol.18 No.11

Microfluidic technologies for circulating tumor cell isolation

Cho, Hyungseok,Kim, Jinho,Song, Hanjung,Sohn, Keun Yong,Jeon, MinHyon,Han, Ki-Ho The Royal Society of Chemistry 2018 The Analyst Vol.143 No.13

<P>Metastasis is the main cause of tumor-related death, and the dispersal of tumor cells through the circulatory system is a critical step in the metastatic process. Early detection and analysis of circulating tumor cells (CTCs) is therefore important for early diagnosis, prognosis, and effective treatment of cancer, enabling favorable clinical outcomes in cancer patients. Accurate and reliable methods for isolating and detecting CTCs are necessary to obtain this clinical information. Over the past two decades, microfluidic technologies have demonstrated great potential for isolating and detecting CTCs from blood. The present paper reviews current advanced microfluidic technologies for isolating CTCs based on various biological and physical principles, and discusses their fundamental advantages and drawbacks for subsequent cellular and molecular assays. Owing to significant genetic heterogeneity among CTCs, microfluidic technologies for isolating individual CTCs have recently been developed. We discuss these single-cell isolation methods, as well as approaches to overcoming the limitations of current microfluidic CTC isolation technologies. Finally, we provide an overview of future innovative microfluidic platforms.</P>

액체 전도도 측정을 위한 고감도 검출기 설계

김남태(Namtae Kim),이승환(Seunghwan Lee),송한정(Hanjung Song),이응선(Eungsun Lee),유승교(Seoungkyo Yoo) 대한전기학회 2010 정보 및 제어 심포지엄 논문집 Vol.2010 No.10

Detector design is presented for the measurement of liquid conductivity. which can be applied to the air monitoring in a fabrication process of semiconductor chips and the level detection of water contamination. A conductivity detector is designed so that it can apply an AC reference signal to a conductance test cell and synchronously detect an output signal from the cell by a lock-in amplifier. A lowpass filter after the amplifier extracts a DC component of an amplifier output proportional to the liquid conductivity in the cell. Measured results of an experimental detector are in close agreement with the predicted results. Its linearity is shown to approach to that of a commercially available conductivity detector.

Fabrication of moth eye-like patterned polystyrene films and their functionalization with polyaniline <i>via</i> interfacial reaction

Modigunta, Jeevan Kumar Reddy,Kim, Jun Mo,Song, Hanjung,Huh, Do Sung Butterworth Scientific Ltd. etc. 2019 Polymer Vol.179 No.-

<P><B>Abstract</B></P> <P>Moth eye-like patterned (MEP) polystyrene (PS) films with a hexagonal array of microdomes mimicking natural moth eye were fabricated by pouring a PS solution on a honeycomb-patterned porous polyvinyl alcohol film using as a template. The surface of microdomes on the PS MEP film containing benzoyl peroxide (BPO) was functionalized with polyaniline (PANI) through interfacial reaction by using aniline hydrochloride to enhance their functionality of the MEP patterned film. The PANI functionalization on the MEP film was confirmed by UV–visible spectroscopy, scanning electron microscopy and EDX analysis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Moth eye-like PS films are fabricated using honeycomb-patterned film as a template. </LI> <LI> The patterned films were functionalized with polyaniline by interfacial reaction. </LI> <LI> The functionalization of PANI was identified by SEM and conductivity of the film. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Microcontroller based Chaotic Lorenz System for Secure Communication Applications

차민드르 자야위크르마,송한정,Jayawickrama, Chamindra,Song, Hanjung The Korea Institute of Information and Commucation 2018 한국정보통신학회논문지 Vol.22 No.12

본 논문에서는 암호통신 응용을 위한 로렌츠 카오스 회로를 구현한다. 이산형 카오스 로렌츠 시스템을 구현하기 위하여, PIC18F 계열의 마이크로 콘트롤러가 사용되었으며, 제안하는 카오스 회로는, 연산증폭기 기반 아날로그 회로와는 다르게, 8 비트PIC 마이크로 콘트롤러 칩과 3개 R-2R 타입의 디지털-아날로그 변환기로 이루어진다. 마이크로 컨트롤러 포트 B, C 및 D에서 시간 파형 X, Y 및 Z가 출력되도록 하였다. 모의실험을 위하여 MATLAB 및 PROTEUS 소프트웨어 플랫폼이 사용되었다. 제안하는 회로에 대하여, MATLAB 및 프로테우스 프로그램에 의한 모의실험을 통하여 시간파형, 주파수 특성, 2차원 위상특성 해석을 실시하였다. 최종적으로, 카오스 시간파형, 2차원(2D) 어트랙터 가 얻어졌고, 카오스 신호에 기반한 아날로그 신호의 암호통신 검증을 실험을 통하여 확인 하였다. This paper presents a implementation of a chaotic Lorenz system for data secure communication applications. Here we have used PIC18F family-based microcontroller to generate the chaotic signal, and simulated waveform patterns confirm that the chaotic behavior of the microcontroller based discrete time chaotic Lorenz system. There are three R-2R ladder type A/D converters have been implemented for conversion of direct microcontroller digital output into analog waveform, utilizing this specific microcontroller relevant to this experiment work, microcontroller ports B, C and D have been utilized for its time waveform outputs X, Y and Z respectively. XC8 compiler used for the compilation of the program. MATLAB and PROTEUS software platforms are used for simulation. Finally, chaotic time wave forms, 2D chaotic attractors were obtained and secure communication analog waveforms were also verified by experimental measurement.

휴대용 멀티기기를 위한 PFM방식의 승압형 DC-DC 변환기

김지만(Jiman Kim),박용수(Yongsu Park),송한정(Hanjung Song) 大韓電子工學會 2010 電子工學會論文誌 IE (Industry electronics) Vol.47 No.3

본 논문은 휴대용 배터리 구동시스템을 위한 다양한 출력전압(5-7V,100㎃)을 가지는 CMOS DC-DC 변환기를 제안한다. 제안하는 DC-DC 변환기는 Pulse-Frequency Modulation (PFM) 방식을 사용하였고, 기준전압회로, 피드백 저항, 컨트롤러, 내부 파형발생기를 사용하였다. 2개의 외부 수동 소자들 (L,C)을 가진 집적화된 DC-DC 변환기는 0.5㎛ 2-poly 4-metal CMOS 공정에서 설계 되었고 PDA, 휴대폰, 노트북 등에 적용 가능하다. In this paper, we describe a CMOS DC-DC converter with a variable output voltage(5-7V @100㎃) for a portable battery-operated system applications. The proposed DC-DC converter is used along with a Pulse-Frequency Modulation (PFM) method and consists of reference circuit, a feedback resistor, a controller, and an internal oscillator. The integrated DC-DC converter with two external passive components(L,C) has been designed and fabricated on a 0.5㎛ 2-poly 3-metal CMOS process and could be applied to the Personal Digital Assistants(PDA), cellular Phone, Laptop Computer, etc.

Photodiode-Based Chua's Circuit with Light Controllability

Nam, Sang Guk,Nguyen, Van Ha,Song, Hanjung Science Press 2014 CHINESE PHYSICS LETTERS Vol.31 No.6

<P>We present a photodiode-based Chua's chaotic circuit that is controllable by light. The proposed circuit consists of an inductor, two passive capacitors, a photodiode-based variable resistor, and a positive feedback transconductor with negative nonlinearity. The chaotic dynamics of the circuit were verified by using the simulation program with integrated circuit emphasis analysis using the 0.35μm complementary metal-oxide-semiconductor process parameters. The gain results (such as the time waveform, frequency analysis, three-dimensional attractor, bifurcation and Lyapunov exponents diagrams) confirm that the chaotic behavior of the circuit could be controlled by light intensity via the photodiode-based variable resistor.</P>

A voltage-controlled chaotic oscillator based on carbon nanotube field-effect transistor for low-power embedded systems

Nguyen, Van Ha,Park, Wonkyeong,Kim, Namtae,Song, Hanjung Chinese Physical Society 2014 Chinese Physics B Vol.23 No.5

<P>This paper presents a compact and low-power-based discrete-time chaotic oscillator based on a carbon nanotube field-effect transistor implemented using Wong and Deng's well-known model. The chaotic circuit is composed of a nonlinear circuit that creates an adjustable chaos map, two sample and hold cells for capture and delay functions, and a voltage shifter that works as a buffer and adjusts the output voltage for feedback. The operation of the chaotic circuit is verified with the SPICE software package, which uses a supply voltage of 0.9 V at a frequency of 20 kHz. The time series, frequency spectra, transitions in phase space, sensitivity with the initial condition diagrams, and bifurcation phenomena are presented. The main advantage of this circuit is that its chaotic signal can be generated while dissipating approximately 7.8 μW of power, making it suitable for embedded systems where many chaos-signal generators are required on a single chip.</P>