• Title/Summary/Keyword: Sensitivity improvement

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An ITO/Au/ITO Thin Film Gas Sensor for Methanol Detection at Room Temperature

  • Jeong, Cheol-Woo;Shin, Chang-Ho;Kim, Dae-Il;Chae, Joo-Hyun;Kim, Yu-Sung
    • Transactions on Electrical and Electronic Materials
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    • v.11 no.2
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    • pp.77-80
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    • 2010
  • Indium tin oxide (ITO) films with a 5 nm thick Au interlayer were prepared on glass substrates. The effects of the Au interlayer on the gas sensitivity for detecting methanol vapors were investigated at room temperature. The conductivity of the film sensor increased upon exposure to methanol vapor and the sensitivity also increased proportionally with the methanol vapor concentration. In terms of the sensitivity measurements, the ITO film sensor with an Au interlayer shows a higher sensitivity than that of the conventional ITO film sensor. This approach is promising in gaining improvement in the performance of ITO gas sensors used for the detection of methanol vapor at room temperature.

Modelling and Sensitivity Analysis for the Performance Improvement of a Spin Coater (스핀 코너 성능향상을 위한 모델링 및 민감도 해석)

  • 권태종;채호철;한창수;정진태;안강호
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.6
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    • pp.96-102
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    • 2000
  • Spinning mechanism is generally used in coasting process on grass plates. Rebounding PR(Photo Resist) which leads to occur inferiority of coating process is caused by vibrational energy of whole coating system. In this study, the sensitivity analysis is performed to analyze and reduce vibrational terms in the spin coating system. The sensitivity analysis is bared on the numerical expression of this system. By the bond graph method. power flow of each system is represented by some basic bond graph elements. Any energy domain system is modeled using the unified elements. The modelled spin coater system is verified with power spectrum data measured by FFT analyzer. As the results of verifying model parameters and sensitivity analysis, principal factors causing vibration phenomenon are mentioned. A study on vibration method in the spin coating system is discussed.

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Fabrication of $In_2O_3$-based oxide semiconductor thick film ozene gas sensor ($In_2O_3$ 계 산화물 반도체형 후막 오존 가스센서의 제조)

  • 이규정
    • Journal of the Korean Institute of Telematics and Electronics T
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    • v.36T no.1
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    • pp.19-24
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    • 1999
  • $In_2O_3$-based thick films for the ozone detection of ppb range have been investigated. The $In_2O_3$ sensing layer is quite sensitive to ozone, but the saturated stable sensitivity cannot be obtained at the ozone exposure of 100 ppb for 5 min. The addition of $Fe_2O_3$ into $In_2O_3$ indicates some improvement in response time and sensitivity, but it seems the improvement is not good enough for real applications. Firing of $In_2O_3$:$Fe_2O_3$ powder induces remarkable improvement in response and recovery, although the sensitivity decrease. The sensing layer fired at $1300^{\circ}C$ and operated $550^{\circ}C$ shows excellent properties of fast response time, saturated stable sensitivity and rapid recovery characteristics to 100 ppb ozone exposure for 5 min. Especially, it shows the reproducibility of the sensor signal for repeated measurements and the linearity between the ozone concentration and the sensor resistance. The preliminary results clearly demonstrated that the sensor can be successfully applied for the ozone detection of ppb range.

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Application of Quality Statistical Techniques Based on the Review and the Interpretation of Medical Decision Metrics (의학적 의사결정 지표의 고찰 및 해석에 기초한 품질통계기법의 적용)

  • Choi, Sungwoon
    • Journal of the Korea Safety Management & Science
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    • v.15 no.2
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    • pp.243-253
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    • 2013
  • This research paper introduces the application and implementation of medical decision metrics that classifies medical decision-making into four different metrics using statistical diagnostic tools, such as confusion matrix, normal distribution, Bayesian prediction and Receiver Operating Curve(ROC). In this study, the metrics are developed based on cross-section study, cohort study and case-control study done by systematic literature review and reformulated the structure of type I error, type II error, confidence level and power of detection. The study proposed implementation strategies for 10 quality improvement activities via 14 medical decision metrics which consider specificity and sensitivity in terms of ${\alpha}$ and ${\beta}$. Examples of ROC implication are depicted in this paper with a useful guidelines to implement a continuous quality improvement, not only in a variable acceptance sampling in Quality Control(QC) but also in a supplier grading score chart in Supplier Chain Management(SCM) quality. This research paper is the first to apply and implement medical decision-making tools as quality improvement activities. These proposed models will help quality practitioners to enhance the process and product quality level.

Effectiveness in the Converged relationship between human rights sensitivity and patient rights awareness through nursing students' human rights sensitivity improvement education (간호대학생의 인권감수성 향상교육을 통한 인권감수성과 환자권리 인식의 융합적 관계에서 효과성)

  • Burm, Eunae;Chun, YeolEo;Choi, Ae-Sook;Gu, Jeung-Ah
    • Journal of the Korea Convergence Society
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    • v.11 no.11
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    • pp.81-88
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    • 2020
  • In this study, an attempt was made to prepare an effective human rights sensitivity education plan for nursing students. This study was before and after a non-equal control group that identified human rights sensitivity and patient rights awareness. As a result of the study, the human rights sensitivity of the subjects averaged 40.22 out of 90 points. The effect on human rights sensitivity through case-based human rights sensitivity education showed that students who received training to improve case-based human rights sensitivity improved human rights sensitivity and patient rights awareness than those who did not(t=2.765,p=.006, t=-5.768,p=.000). As a result of this study, it is considered that the foundation of the curriculum to improve the human rights sensitivity of nursing students should be prepared. We propose a later study on the relationship between clinical practice and human rights sensitivity.

A Polysilicon Field Effect Transistor Pressure Sensor of Thin Nitride Membrane Choking Effect of Right After Turn-on for Stress Sensitivity Improvement (스트레스 감도 향상을 위한 턴 온 직후의 조름 효과를 이용한 얇은 질화막 폴리실리콘 전계 효과 트랜지스터 압력센서)

  • Jung, Hanyung;Lee, Junghoon
    • Journal of Sensor Science and Technology
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    • v.23 no.2
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    • pp.114-121
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    • 2014
  • We report a polysilicon active area membrane field effect transistor (PSAFET) pressure sensor for low stress deflection of membrane. The PSAFET was produced in conventional FET semiconductor fabrication and backside wet etching. The PSAFET located at the front side measured pressure change using 300 nm thin-nitride membrane when a membrane was slightly strained by the small deflection of membrane shape from backside with any physical force. The PSAFET showed high sensitivity around threshold voltage, because threshold voltage variation was composed of fractional function form in sensitivity equation of current variation. When gate voltage was biased close to threshold voltage, a fractional function form had infinite value at $V_{tn}$, which increased the current variation of sensitivity. Threshold voltage effect was dominant right after the PSAFET was turned on. Narrow transistor channel established by small current flow was choked because electron could barely cross drain-source electrodes. When gate voltage was far from threshold voltage, threshold voltage effect converged to zero in fractional form of threshold voltage variations and drain current change was mostly determined by mobility changes. As the PSAFET fabrication was compatible with a polysilicon FET in CMOS fabrication, it could be adapted in low pressure sensor and bio molecular sensor.

Magnetic Sensitivity Improvement of 2-Dimensional Silicon Vertical Hall Device (2 차원 Si 종형 Hall 소자의 자기감도 개선)

  • Ryu, Ji-Goo
    • Journal of Sensor Science and Technology
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    • v.23 no.6
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    • pp.392-396
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    • 2014
  • The 2-dimensional silicon vertical Hall devices, which are sensitive to X,Y components of the magnetic field parallel to the surface of the chip, are fabricated using a modified bipolar process. It consists of the thin p-layer at Si-$SiO_2$ interface and n-epi layer to improve the sensitivity and influence of interface effect. Experimental samples are a sensor type K with and type J without $p^+$ isolation dam adjacent to the center current electrode. The results for both type show a more high sensitivity than the former's 2-dimensional vertical Hall devices and a good linearity. The measured non-linearity is about 0.8%. The sensitivity of type J and type K are about 66 V/AT and 200 V/AT, respectively. This sensor's behavior can be explained by the similar J-FET model.

A Refined Semi-Analytic Sensitivity Study Based on the Mode Decomposition and Neumann Series Expansion in Eigenvalue Problem(II) - Eigenvalue Problem - (강체모드분리와 급수전개를 통한 고유치 문제에서의 준해석적 설계 민감도 개선에 관한 연구(II) -동적 문제 -)

  • Kim, Hyun-Gi;Cho, Maeng-Hyo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.4
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    • pp.593-600
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    • 2003
  • Structural optimization often requires the evaluation of design sensitivities. The Semi Analytic Method(SAM) fur computing sensitivity is popular in shape optimization because this method has several advantages. But when relatively large rigid body motions are identified for individual elements. the SAM shows severe inaccuracy. In this study, the improvement of design sensitivities corresponding to the rigid body mode is evaluated by exact differentiation of the rigid body modes. Moreover. the error of the SAM caused by numerical difference scheme is alleviated by using a series approximation for the sensitivity derivatives and considering the higher order terms. Finally the present study shows that the refined SAM including the iterative method improves the results of sensitivity analysis in dynamic problems.

Magnetic Sensitivity Improvement of Silicon Vertical Hall Device (Si 종형 Hall 소자의 자기감도 개선)

  • Ryu, Ji-Goo;Kim, Nam-Ho;Chung, Su-Tae
    • Journal of Sensor Science and Technology
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    • v.20 no.4
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    • pp.260-265
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    • 2011
  • The silicon vertical hall devices are fabricated using a modified bipolar process. It consists of the thin p-layer at Si-$SiO_2$, interface and n-epi layer without $n^+$buried layer to improve the sensitivity and influence of interface effects. Experimental samples are a sensor type I with and type H without p+isolation dam adjacent to the center current electrode. The experimental results for both type show a more high current-related sensitivity than the former's vertical hall devices. The sensitivity of type H and type I are about 150 V/AT and 340 V/AT, respectively. This sensor's behavior can be explained by the similar J-FET model.

Fabrication of Polyimide Film Electrode by Laser Ablation and Application for Electrochemical Glucose Biosensor (Laser ablation을 이용한 폴리이미드 필름 전극제조 및 전기화학적 글루코오즈 바이오센서 응용)

  • Park, Deog-Su
    • Journal of Sensor Science and Technology
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    • v.22 no.5
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    • pp.357-363
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    • 2013
  • An ultraviolet pulsed laser ablation of polyimide film coated with platinum has been used to enhance the sensitivity for the application as an electrochemical biosensor. Densely packed cones are formed on polyimide surface after UV irradiation which results in increase of surface area. In order to apply the sensitivity improvement of laser ablated polyimide film electrodes, the glucose oxidase modified biosensor was fabricated by using an encapsulation in the gel matrix through sol-gel transition of tetraethoxysliane on the surface of laser ablated polyimide film. The optimum conditions for glucose determination have been characterized with respect to the applied potential and pH. The linear range and detection limit of glucose detection were from 2.0 mM to 18.0 mM and 0.18 mM, respectively. The sensitivity of glucose biosensors fabricated with laser ablated polyimide film is about three times higher than that of plain polyimide film due to increase in surface area by laser ablation.