Fabrication of low power micro-heater for micro-gas sensor II. Characteristics of micro-gas sensor

정완영,이상문,강봉휘,장동근,이덕동,노보루 야마조애,Chung, Wan-Young,Lee, Sang-Moon,Kang, Bong-Hwi,Jang, Dong-Kun,Lee, Duk-Dong,Yamazoe, Noboru The Korean Sensors Society 1997 센서학회지 Vol.6 No.3

A new planar-type microsensor, which had a platinum heater and a sensing layer on the same plane was fabricated on silicon substrate with stress-relieved PSG(phosphosilicate glass)/$Si_{3}N_{4}$(800nm/150nm) diaphragm. The proposed planar-type microsensor could be fabricated by simple silicon process using only 3 masks for photolithography process compared with 5 or 6 masks of the typical micro-gas sensor. The thermal properties of the microsensor from thermal simulation were compared with those of the fabricated microheater. Although there are some discrepancy between the simulation result and the result from the fabricated microheater, the thermal simulation by FEM was proved to be an useful method to evaluate the thermal properties of microheater. The sensing characteristics of the fabricated microsensor with the planar-type heater were investigated also.

Fabrication of 1D Metal Oxide Nanostructures Using Glancing Angle Deposition for High Performance Gas Sensors

Suh, Jun Min,Jang, Ho Won The Korean Sensors Society 2017 센서학회지 Vol.26 No.4

Gas sensors based on metal-oxide-semiconductors are predominantly used in numerous applications including monitoring indoor air quality and detecting harmful substances such as volatile organic compounds. Nanostructures, e.g., nanoparticles, nanotubes, nanodomes, or nanofibers, have been widely utilized to improve the gas sensing properties of metal-oxide-semiconductors by increasing the effective surface area participating in the surface reaction with target gas molecules. Recently, 1-dimensional (1D) metal oxide nanostructures fabricated using glancing angle deposition (GAD) method with e-beam evaporation have been widely employed to increase the surface-to-volume ratio significantly with large-area uniformity and reproducibility, leading to promising gas sensing properties. Herein, we provide a brief overview of 1D metal oxide nanostructures fabricated using GAD and their gas sensing properties in terms of fabrication methods, morphologies, and additives. Moreover, the gas sensing mechanisms and perspectives are presented.

Cutting-edge Piezo/Triboelectric-based Wearable Physical Sensor Platforms

Park, Jiwon,Shin, Joonchul,Hur, Sunghoon,Kang, Chong-Yun,Cho, Kyung-Hoon,Song, Hyun-Cheol The Korean Sensors Society 2022 센서학회지 Vol.31 No.5

With the recent widespread implementation of Internet of Things (IoT) technology driven by Industry 4.0, self-powered sensors for wearable and implantable systems are increasingly gaining attention. Piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs), which convert biomechanical energy into electrical energy, can be considered as efficient self-powered sensor platforms. These are energy harvesters that are used as low-power energy sources. However, they can also be used as sensors when an output signal is used to sense any mechanical stimuli. For sensors, collecting high-quality data is important. However, the accuracy of sensing for practical applications is equally important. This paper provides a brief review of the performance advanced by the materials and structures of the latest PENG/TENG-based wearable sensors and intelligent applications applied using artificial intelligence (AI)

SOl Pressure Sensors

정귀상,석전성,중촌철랑,Chung, Gwiy-Sang,Ishida, Makoto,Nakamura, Tetsuro The Korean Sensors Society 1994 센서학회지 Vol.3 No.1

This paper describes the characteristics of a piezoresistive pressure sensor fabricated on a SOI (Si-on-insulator) structure, in which the SOI structures of Si/$SiO_{2}$/Si and Si/$Al_{2}O_{3}$/Si were formed by SDB (Si-wafer direct bonding) technology and hetero-epitaxial growth, respectively. The SOI pressure sensors using the insulator of a SOI structure as the dielectrical isolation layer of piezoresistors, were operated at higher temperatures up to $300^{\circ}C$. In the case of pressure sensors using the insulator of a SOI structure as an etch-stop layer during the formation of thin Si diaphragms, the pressure sensitivity variation of the SOI pressure sensors was controlled to within a standard deviation of ${\pm}2.3%$ over 200 devices. Moreover, the pressure sensors fabricated on the double SOI ($Si/Al_{2}O_{3}/Si/SiO_{2}/Si$) structures formed by combining SDB technology with epitaxial growth also showed very excellent characteristics with high-temperature operation and high-resolution.

Body Composition Variations in the Paretic and Nonparetic Regions of Patients with Strokes Caused by Cerebral Hemorrhage or Cerebral Infarction

Yoo, Chan-Uk,Kim, Jae-Hyung,Kim, Gun-Ho,Hwang, Young-Jun,Jeon, Gye-Rok,Baik, Seong-Wan The Korean Sensors Society 2017 센서학회지 Vol.26 No.5

Indicators to quantitatively evaluate the body function may help to optimize the effectiveness of rehabilitation therapy for stroke patients. In this study, we analyzed the body composition in the paretic and nonparetic regions of stroke patients with hemiplegia caused by cerebral hemorrhage (7 cases) and cerebral infarction (13 cases) using multifrequency bioelectrical impedance. Specifically, we considered fat mass (FM), fat-free mass (FFM), FFMI index (FFMI), FM/FFM relation, body cell mass (BCM), basal metabolic rate (BMR), and BMR/FFM relation to evaluate the bodily function in the paretic and nonparetic regions. These values showed considerable differences according to grades determined by the stroke causes and the paralysis status. In the paretic regions, the FFM, FFMI, BCM, and BMR were low and the FM was high. In contrast, the nonparetic regions showed a high FFM and low FM. Furthermore, the paretic and nonparetic regions of all patients suitably fit a linear relation (slope: 22.17 kcal/day/kg) between BMR and FFM. Therefore, bio-electrical impedance measurements can be very useful to quantitatively assess paretic and nonparetic regions in hemiplegic stroke patients.

Radial Electrical Impedance: A Potential Indicator for Noninvasive Cuffless Blood Pressure Measurement

Huynh, Toan Huu,Chung, Wan-Young The Korean Sensors Society 2017 센서학회지 Vol.26 No.4

Noninvasive, cuffless, and continuous blood pressure (BP) monitoring is essential to prevent and control hypertension. A well-known existing method for this measurement is pulse transit time (PTT), which has been investigated by many researchers as a promising approach. However, the fundamental principle of the PTT method is based on the time interval taken by a pulse wave to propagate between the proximal and distal arterial sites. Consequently, this method needs an independent system with two devices placed at two different sites, which is a problem. Even though some studies attempted to synchronize the system, it is bulky and inconvenient by contemporary standards. To find a more sensitive method to be used in a BP measurement device, this study used radial electrical bioimpedance (REB) as a potential indicator for BP determination. Only one impedance plethysmography channel at the wrist is performed for demonstrating a ubiquitous BP wearable device. The experiment was evaluated on eight healthy subjects with the ambulatory BP monitor on the upper arm as a reference. The results demonstrated the potential of the proposed method by the correlation of estimated systolic (SBP) and diastolic (DBP) BP against the reference at $0.84{\pm}0.05$ and $0.83{\pm}0.05$, respectively. REB also tracked the DBP well with a root-mean-squared-error of $7.5{\pm}1.35mmHg$.

FABRICATIO0N OF NASICON ELECTROLYTES

최순돈,박정우,Choi, Soon-Don,Park, Jung-Woo The Korean Sensors Society 1995 센서학회지 Vol.4 No.1

Conventional ball-milling technique was used to synthesize NASICON powders. The NASICON powders were made from three kinds of component powders : coarse($ZrO_{2}$, $Na_{3}PO_{4}$, $SiO_{2}$), fine ($ZrO_{2}$, $Na_{3}PO_{4}$, $SiO_{2}$) and fine ($ZrSiO_{4}$, $Na_{3}PO_{4}$) powders. The fine component powders were easily reacted to form the desired product at $1100^{\circ}C$ or higher, whereas incomplete reaction due to the coarse component powders occurred even at $1170^{\circ}C$. The finer the grain size of the starting powders was, the higher the bulk density of NASICON electrolyte after sintering was observed. Almost single phase NASICON electrolytes with more than 95% of the theoretical density, $3.27g/cm^{3}$, could be fabricated by sintering for $40{\sim}60$ hours at temperatures between 1150 and $1170^{\circ}C$.

Erratum to "Computational analysis of the effect of SOI vertical slot optical waveguide specifications on integrated-optic biochemical waveguide wensitivity"

Jung, Hongsik The Korean Sensors Society 2022 센서학회지 Vol.31 No.1

Wearable Human Health-monitoring Band using Inkjet-printed Flexible Temperature Sensor

Han, Dong Cheul,Shin, Han Jae,Yeom, Se Hyeok,Lee, Wanghoon The Korean Sensors Society 2017 센서학회지 Vol.26 No.5

This paper presents a wearable human health-monitoring band. The band consists of a body temperature detector (BTD) and a hear rate detector (HRD). The BTD and HRD are realized using an inkjet-printed flexible temperature sensor and a commercial heart rate sensor module, respectively. The sensitivity of the fabricated BTD was found to be $-31/^{\circ}C$ with a linearity of 99.82%. The HRD using the commercial heart rate sensor module has a good performance with a standard deviation of 0.85 between the data of a commercial smart watch and the fabricated HRD.

Olfactory Interaction based on ISO/IEC 23005 Standard

Choi, Jang-Sik,Chang, Sung-June,Lee, Hae-Ryong,Byun, Hyung-Gi The Korean Sensors Society 2017 센서학회지 Vol.26 No.5

Realistic media comprised of metadata of the five senses to provide enhanced experiences by stimulating our memory and sensations have had an increasingly pervading effect in our daily lives. Many researchers and companies are in the process of developing their own authoring systems running on different platforms to serve realistic media, resulting in compatibility issues among the systems. To tackle these issues, the International Organization for Standardization have standardized the interface, data format, protocol, API, etc. required to provide the realistic media. In particular, the ISO/IEC 23005 standard, which is called MPEG-V in SC29/WG 11, has defined XML schemas for olfaction interaction based on electronic nose (E-Nose), and scent display. In this paper, the MPEG-V standard for olfaction interaction is reviewed, and a data flow diagram that can be used for olfactory interaction based on the MPEG-V standard was designed. In addition, the necessary schemas related to the E-Nose sensor for olfactory interaction was provided.