0.18 μm CMOS 공정으로 설계된 아날로그-디지털 변환기를 내장한 Wireless 온도 센서 설계

파함 듀이 동,트란 난,이 종욱 경희-다반 ASIC 설계교육센터 2006 경희-다반 ASIC센터 논문집 Vol.7 No.-

A simple and practical architecture for RF-powered wireless temperature sensor is presented. The tag chip receives its power supply from a RF-DC converter which recovers DC power from a small incident signal. Ambient temperature is estimated by a temperature-voltage converter, and a single-slope ADC converts the temperature-dependent voltage to digital data. This approach does not depend on the temperature dependence of oscillator frequency, thus, does not require complex post processing such as laser trimming in the practical implementation of the temperature sensor. With on chip ADC, this proposed temperature sensor has a sensitivity of 6744 ppm/oC. We investigated the operation of the wireless, remotely-power sensor tag chip using standard 0.18 pm CMOS technology.

0.35 μm CMOS 공정으로 제작된 UHF 대역 RFID 태그 칩 통신 제어부 설계

트란 난,파함 듀이 동,이 종욱 경희-다반 ASIC 설계교육센터 2006 경희-다반 ASIC센터 논문집 Vol.7 No.-

We present the control circuit for reader to tag communication in UHF band RFID tag chip. The system clock of tag chip is generated by the internal oscillator with digital calibration to maintain stable clock signal. The control circuit designed using standard 0.35 pm CMOS process shows the correct operation of analog front-end of RFID tag chip. Together with verifying the combination of circuits of the analog front end, we present the design considerations of the comparator with internal hysteresis and the internal oscillator with calibration.

Composites derived from synthetic clay and carbon sphere: Preparation, characterization, and application for dye decontamination

Nguyen Duy Dat,Ton That Loc,Mai Thuan Trieu,Dong Thanh Nguyen,Khuong Quoc Nguyen,My Linh Nguyen,Anh Duy Duong Le,Hai Nguyen Tran 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.4

Two new composites from synthetic clay-like materials and carbon spheres were developed. Layered doubledhydroxides (LDH) were synthesized from the coprecipitation of Mg2+ and Al3+ ions. Spherical hydrochar (SH) wasprepared from pure glucose through hydrothermal carbonization at 190 oC. The composite LDH–SH was synthesizedthrough a simple hydrothermal method of the mixture of LDH and SH. Another composite, LDO-SB, was directly preparedthrough the carbonization of LDH-SH at 500 oC. Under such high temperature, LDH was converted to layereddoubled oxides (LDO), and SH was transferred to spherical biochar (SB). Those materials were characterized by chemicalstability, surface morphology and element composition, crystal structure, surface functional group, and texturalcharacteristic. They were applied for removing cationic dye (methylene blue; MB) and anionic dye (Congo red; CR)under different pH solutions. Three adsorption components—kinetics, isotherm, and thermodynamics—were conductedunder batch experimenters. Results demonstrated that the LDH or LDO particles were assembled on the surfaceof SH or SB, respectively. The surface area, total pore volume, and average pore width of LDH–SH and LDO-SBwere 58.5 and 198m2/g, 0.319 and 0.440 cm3/g, and 21.8 and 8.89 nm, respectively. The maximum adsorption capacityof the materials, calculated from the Langmuir model, at 30 oC for CR and MB dyes was 1589 and 78.6mg/g (LDOSB)and 499 and 226mg/g (LDH-SH), respectively. The composites exhibited a higher affinity to anionic than cationicdyes, which resulted from the great contribution of the clay-like materials. Therefore, they can serve as a promisingcomposite for the decolorization of wastewater.

Damage detection in beam-type structures via PZT’s dual piezoelectric responses

Khac-Duy Nguyen,김정태,Duc-Duy Ho 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.11 No.2

In this paper, practical methods to utilize PZT’s dual piezoelectric effects (i.e., dynamic strain and electro-mechanical (E/M) impedance responses) for damage detection in beam-type structures are presented. In order to achieve the objective, the following approaches are implemented. Firstly, PZT material’s dual piezoelectric characteristics on dynamic strain and E/M impedance are investigated. Secondly, global vibration-based and local impedance-based methods to detect the occurrence and the location of damage are presented. Finally, the vibration-based and impedance-based damage detection methods using the dual piezoelectric responses are evaluated from experiments on a lab-scaled beam for several damage scenarios. Damage detection results from using PZT sensor are compared with those obtained from using accelerometer and electric strain gauge.

A Time-Dependent Corrosion Characteristic of a Steel Member in Contact with Concrete

Dao, Duy Kien,Nguyen, Duy Khiem,Kim, Hyoung-Seok,Jeong, Young-Soo,Kim, In-Tae Springer-Verlag 2018 International Journal of Steel Structures Vol.18 No.3

Solar-powered multi-scale sensor node on Imote2 platform for hybrid SHM in cable-stayed bridge

Duc-Duy Ho,김정태,Khac-Duy Nguyen,홍동수,이소영,신성우,윤정방,Masanobu Shinozuka,Po-Young Lee 국제구조공학회 2012 Smart Structures and Systems, An International Jou Vol.9 No.2

In this paper, solar-powered, multi-scale, vibration-impedance sensor node on Imote2 platform is presented for hybrid structural health monitoring (SHM) in cable-stayed bridge. In order to achieve the objective, the following approaches are proposed. Firstly, vibration- and impedance-based hybrid SHM methods are briefly described. Secondly, the multi-scale vibration and impedance sensor node on Imote2- platform is presented on the design of hardware components and embedded software for vibration- and impedance-based SHM. In this approach, a solar-powered energy harvesting is implemented for autonomous operation of the smart sensor nodes. Finally, the feasibility and practicality of the smart sensor-based SHM system is evaluated on a full-scale cable-stayed bridge, Hwamyung Bridge in Korea. Successful level of wireless communication and solar-power supply for smart sensor nodes are verified. Also, vibration and impedance responses measured from the target bridge which experiences various weather conditions are examined for the robust long-term monitoring capability of the smart sensor system.

Imote2/SHM-DAQ 센서노드와 PZT 센서를 이용한 케이블 장력 모니터링

Nguyen Khac Duy,Ho Duc Duy,김정태 한국구조물진단유지관리학회 2012 한국구조물진단학회 학술발표회논문집 Vol.2012 No.1

This study presents a method to monitor cable force using an Imote2/SHM-DAQ sensor node and a PZT sensor. The following approaches are carried out to achieve the objective. Firstly, the principle of piezoelectric material (e.g., PZT) as a strain sensor is reviewed. According to its piezoelectric features, the use of PZT sensor for strain measurement of a stay cable is presented. Secondly, the design of the data acquisition sensor node Imote2/SHM-DAQ is described. The sensor node is used to monitor strain-induced voltage from the PZT sensor. The advantages of the system are cheap, and enable for wireless communication and automated operation. Finally, the feasibility of the sensing system is evaluated on a lab-scale stay cable.

Reduced graphene oxide–Nickel sulfide (NiS) composited on mechanical pencil lead as a versatile and cost-effective sensor for electrochemical measurements of bisphenol A and mercury (II)

Vu, Tung Duy,Khac Duy, Pham,Bui, Hoa Thi,Han, Sung-Hwan,Chung, Hoeil Elsevier 2019 Sensors and actuators. B Chemical Vol.281 No.-

<P><B>Abstract</B></P> <P>NiS is a highly promising transition metal sulfide versatile for a sensor material owing to its superior conductivity and stability, and herein we report its first incorporation into an electrochemical sensor. Because exposure to electrolyte under electrochemical impact can easily deform NiS, thereby decreasing its electro-activity and measurement reproducibility, a strategy for optimally integrating NiS into sensors is critically necessary. For this purpose, NiS was initially firmly affixed to a mechanical pencil lead (MPL) by means of hydrothermal deposition (with the result designated as MPL-NiS). MPL, a commercially available carbon-based material with consistent quality, was adopted to make the sensor cost-effective and easily prepared. Then, to prevent direct exposure of NiS to samples during electrochemical measurement and to make the sensor surface more reactive for wide variety of analytes, reduced graphene oxide (rGO) was electrodeposited on the NiS surface to construct a final structure of MPL-NiS/rGO. In summary, NiS, a <I>p</I>-type semiconductor with positive charge, was effectively composited and sandwiched with negatively charged rGO and MPL by means of mutual electrostatic interaction. When the developed MPL-NiS/rGO sensor was used to separately measure bisphenol A (BPA) and mercury- Hg<SUP>2+</SUP>, the sensitivity and sensor-to-sensor reproducibility were comparable with or superior to those of previously reported sensors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> NiS is a promising material for electrochemical sensing owing to its good conductivity and stability. </LI> <LI> NiS was integrated with MPL and rGO to build a versatile and cheap sensor. </LI> <LI> For fabrication, NiS was initially deposited on the MPL surface by a hydrothermal method. </LI> <LI> rGO was then electrodeposited on the NiS surface to form a complete MPL-NiS/rGO sensor. </LI> <LI> The sensor showed superior sensitivity and reproducibility in measurements of BPA and Hg (II). </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Prediction of the Spin-Parities and the Magnetic Moments for the Ground States of Proton-rich Nuclei with Z = 21–30

Ly Nguyen Duy,Xayavong Latsamy,Uyen Nguyen Kim,Pham Vinh N. T.,Hao T. V. Nhan,Duy Nguyen Ngoc 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.11

The present paper reports on the spin-parities and the magnetic moments for the ground states of 44 proton-rich isotopes with Z = 21-30 and A = 36-57, which are important for studies of either reaction rates in X-ray bursts or nuclear structure. These nuclear properties were calculated based on the single-particle shell model. The spins of the concerned nuclei were compared to available experimental data adopted from the NuDat database to evaluate the variations in the astrophysical rates of the rp-process reactions. We found discrepancies, due to the deformed nuclear structure, between the present results and those reported in the NuDat database. The spin uncertainties result in large variations, 13% - 200%, in the astrophysical rates of the rp-process reactions. In particular, the spin uncertainties of the 44V and the 46-49Mn isotopes significantly affect the astrophysical rates of the reverse reactions of the proton captures 43Ti(p,γ)44V$(p,γ)45Cr, 45Cr(p,γ)46Mn(p,γ)47Fe, 47Mn(p,γ)48Fe, 47Cr(p,γ)48Mn(p,γ)49Fe, and 48Cr(p,γ)49Mn(p,γ)50Fe. Moreover, the magnetic moments of most of the isotopes were predicted for the first time. The results show that the magnetic moments are in the order of μp(1f7/2) > μp(2p3/2) > μn(1d3/2)> μn(1f7/2) for the nuclei having an unpaired nucleon in the proton/neutron shells. The present study suggests that reliable calculations and/or measurements for the properties of proton-rich nuclei are highly demanded.

Solar-powered multi-scale sensor node on Imote2 platform for hybrid SHM in cable-stayed bridge

Ho, Duc-Duy,Lee, Po-Young,Nguyen, Khac-Duy,Hong, Dong-Soo,Lee, So-Young,Kim, Jeong-Tae,Shin, Sung-Woo,Yun, Chung-Bang,Shinozuka, Masanobu Techno-Press 2012 Smart Structures and Systems, An International Jou Vol.9 No.2

In this paper, solar-powered, multi-scale, vibration-impedance sensor node on Imote2 platform is presented for hybrid structural health monitoring (SHM) in cable-stayed bridge. In order to achieve the objective, the following approaches are proposed. Firstly, vibration- and impedance-based hybrid SHM methods are briefly described. Secondly, the multi-scale vibration and impedance sensor node on Imote2-platform is presented on the design of hardware components and embedded software for vibration- and impedance-based SHM. In this approach, a solar-powered energy harvesting is implemented for autonomous operation of the smart sensor nodes. Finally, the feasibility and practicality of the smart sensor-based SHM system is evaluated on a full-scale cable-stayed bridge, Hwamyung Bridge in Korea. Successful level of wireless communication and solar-power supply for smart sensor nodes are verified. Also, vibration and impedance responses measured from the target bridge which experiences various weather conditions are examined for the robust long-term monitoring capability of the smart sensor system.