• 센서학회지
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• 제27권4호
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• pp.269-274
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• 2018

High-sensitivity signal-to-noise ratio (SNR) microphones are essentially required for a broad range of automatic speech recognition applications. Piezoelectric microphones have several advantages compared to conventional capacitor microphones including high stiffness and high SNR. In this study, we designed a new piezoelectric membrane structure by using the finite elements method (FEM) and an optimization technique to improve the sensitivity of the transducer, which has a high-quality AlN piezoelectric thin film. The simulation demonstrated that the sensitivity critically depends on the inner radius of the top electrode, the outer radius of the membrane, and the thickness of the piezoelectric film in the microphone. The optimized piezoelectric transducer structure showed a much higher sensitivity than that of the conventional piezoelectric transducer structure. This study provides a visible path to realize micro-scale high-sensitivity piezoelectric microphones that have a simple manufacturing process, wide range of frequency and low DC bias voltage.

• 한국치위생학회지
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• 제20권3호
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• pp.303-312
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• 2020

Objectives: The purpose of this study was to investigate the relationship between periodontal disease, number of remaining teeth with high-sensitivity C-Reactive protein in Korean adults aged 40 and older. Methods: The study used the Sixth Korea National Health and Nutrition Examination Survey (KNHANES VI-3), 2015. The study sample consisted of 3,883 aged 40 years or older who had completed the health survey and the health examination. Logistic regression analyses were performed to examine the odds ratios of high-sensitivity C-Reactive protein by periodontal disease and number of remaining teeth, adjusting for demographic characteristics, chronic diseases and oral health behavior-related variables. Results: When the demographic and chronic diseases were adjusted, the risk of high-sensitivity C-Reactive protein (hs-CRP) average 1.23 mg/L or higher was 1.36 times higher in patients with periodontal disease between the ages of 40 and 49, but it was not significant (OR=1.36; 95% CI=0.82-2.23). In addition, in the group of 0~23 remaining teeth aged 40~49 years, the risk of higher than the average 1.23 mg/L of high-sensitivity C-Reactive protein was 2.03 times higher (OR=2.03; 95% CI=1.10-3.74), and 1.49 times higher in 60~69 years (OR=1.07; 95% CI=1.04-2.76). Conclusions: This study found that periodontal disease and tooth loss in Korean adults aged 40 and older was significantly associated with high-sensitivity C-reactive protein.

• 한국환경과학회지
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• 제20권11호
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• pp.1465-1481
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• 2011

The accuracy of ozone sensitivity coefficients estimated with HDDM (High-order Decoupled Direct Method) can vary depending on the $NO_x$ (Nitrogen Oxides) and VOC (Volatile Organic Compound) conditions. In order to evaluate the applicability of HDDM over the Seoul Metropolitan Area (SMA) during a high ozone episode in 2007 June, we compare BFM (Brute Force Method) and HDDM in terms of the $1^{st}$-order ozone sensitivity coefficient to explain ozone change in response to changes in NOx and VOC emissions, and the $2^{nd}$-order ozone sensitivity coefficient to represent nonlinear response of ozone to the emission changes. BFM and HDDM estimate comparable ozone sensitivity coefficients, exhibiting similar spatial and temporal variations over the SMAduring the episode. NME (Normalized Mean Error) between BFM and HDDM for the episode average $1^{st}$- and $2^{nd}$-order ozone sensitivity coefficients to NOx and VOC emissions are less than 3% and 9%, respectively. For the daily comparison, NME for the $1^{st}$- and $2^{nd}$-order ozone sensitivity coefficients are less than 4% ($R^2$ > 0.96) and 15% ($R^2$ > 0.90), respectively. Under the emission conditions used in this study, two methods show negative episode average $1^{st}$-order ozone sensitivity coefficient to $NO_x$ emissions over the core SMA. The $2^{nd}$-order ozone sensitivity coefficient to $NO_x$ emissions leads ozone to respond muchnonlinear to the reduction in $NO_x$ emissions over Seoul. Nonlinear ozone response to reduction in VOC emissions is mitigated due to the $2^{nd}$-order ozone sensitivity coefficient which is much smaller than the $1^{st}$-order ozone sensitivity coefficient to the emissions in the magnitude.

• Journal of Nutrition and Health
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• 제35권7호
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• pp.754-762
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• 2002

This study was performed to investigate the effect of sodium intake on blood pressure and blood parameters. 20 young adult women were fed the diets containing 290.5 mEq (high-Na diet) and 51.3 mEq (low-Na diet) Na for 6 days, respectively. BMI, DBP, and MBP were significantly lower in low-Na diet than those in high-Na diet. 20 subjects were divided into 3 groups according to the salt-sensitivity. In salt-sensitive group, decreases in SBP, DBP, and MBP by low-Na diet were shown. And there were not significant difference in blood pressure of salt-resistant group between high- and low-Na diet. In count-reactive group, MBP in low-Na diet was significantly higher than that in high-Na diet. Hemoglobin, creatinine, uric acid, and haptoglobin levels in serum were significantly higher in low-Na diet than those in high-Na diet. Among groups with different salt-sensitivity, increments of haptoglobin by low-Na diet were shown in salt-sensitive and counter-reactive groups. Actually, low sodium diet affects not only the blood pressure, but other biochemical parameters which in turn affect an individual overall health. Also salt-sensitivity should be considered as an important determinant. Therefore, for the patients who need restricted Na diet, it would be suggested that various biochemical changes and individual salt-sensitivity should be carefully considered along with dietary Na manipulation.

• Journal of the Optical Society of Korea
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• 제14권1호
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• pp.14-21
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• 2010

Fiber ring laser based intra-cavity absorption spectroscopic sensor has great potential for high sensitivity gas detection. Using the rate equations and propagation equations, we investigated theoretically factors that affect the sensitivity of such fiber ring laser sensors and determined the optimal design parameters and conditions for significant enhancement of the system sensitivity. Experiments have been conducted to determine the sensitivity enhancement performance. The results showed a factor of 25 ~ 30 in sensitivity enhancement in the experimental system, agreeing well with the theoretical expectations. Experiments on acetylene detection have also been carried out and the results showed that the ring cavity significantly increases the signal absorption and that high sensitivity can be obtained for gas detection.

• Current Optics and Photonics
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• 제7권2호
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• pp.200-206
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• 2023

Near-infrared (NIR) sensing technology using CMOS image sensors is used in many applications, including automobiles, biological inspection, surveillance, and mobile devices. An intuitive way to improve NIR sensitivity is to thicken the light absorption layer (silicon). However, thickened silicon lacks NIR sensitivity and has other disadvantages, such as diminished optical performance (e.g. crosstalk) and difficulty in processing. In this paper, a pixel structure for NIR sensing using a stacked CMOS image sensor is introduced. There are two photodetection layers, a conventional layer and a bottom photodiode, in the stacked CMOS image sensor. The bottom photodiode is used as the NIR absorption layer. Therefore, the suggested pixel structure does not change the thickness of the conventional photodiode. To verify the suggested pixel structure, sensitivity was simulated using an optical simulator. As a result, the sensitivity was improved by a maximum of 130% and 160% at wavelengths of 850 nm and 940 nm, respectively, with a pixel size of 1.2 ㎛. Therefore, the proposed pixel structure is useful for NIR sensing without thickening the silicon.

• Journal of Nutrition and Health
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• 제22권4호
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• pp.266-274
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• 1989

The current study was undertaken to determine the effects of the ratios of dietary fat to carbohydrate and energy restriction on insulin sensitivity in the growing rats. Male rats weighting 80-90g were fed experimental diets for two weeks. Rats were killed and epiddymal adipose tissue were removed and sliced. Explants of adipose tissues were incubated for 2 hours in KRB(Krebs-Ringer bicarbonate) buffer containing various concentrations of human insulin and [U-14C]glucose. Insulin sensitivity was determined as glucose conversion to total lipids (lipogenesis) during 2 hr incubation. Exp't I : Effects of Ratios of Fat to Carbohydrate on Insulin Sensitivity. Eighteen male rats were fed 3 diets for 2 weeks. Diet 1 was low fat-high carbohydrate (4% soybean oil and 66.5% cornstarch) ; diet 2, medium fat-medium sarbohydrate(12% soybean oil and 58.5% cornstarch) ; diet 3, high fat-low carbohydrate (20% soybean oil and 50.5% cornstarch). Insulin sensitivity was higher in the order of LF-HC, MF-HC and HF-LC diet groups (p<0.05), i.e, lipogenesis was higher at all insuline concentration in the explants from rats fed LF-HC diet. However, thers was no significant difference in body weight gain and epididymal adipose tissue weight among treatments. Exp't II ; Effects of Energy Restriction on Insulin Sensitivity. Twelve rats were grouped into ad libitum feeding and restricted feeding(70% of ad libitum). The experimental diet was medium fat-medium carbohydrat diet as used in the Exp't I. Restricted feeding group tended to show higher insulin sensitivity compared to ad libitum group. However, there was no statistical difference between two groups. As expected, body weight gain and epididymal adipose tissue were higher in the ad libitum group. In summary, the resutls of the current study showed that the epididymal adipose tissue taken from the rats fed low fat-high carbohydrate diet showed higher insulin sensitivity compared to those fed high fat-low carbohydrate, and that resticted feeding tended to elevate insulin sensitivity in these tissues.

• 치위생과학회지
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• 제21권2호
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• pp.111-118
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• 2021

Background: This study was conducted to identify the level of gender sensitivity and gender equality consciousness among dental hygiene students and to confirm the necessity of gender equality programs in the curriculum. Methods: A self-report questionnaire was conducted with some dental hygiene students using the Gender Sensitivity tool and Korean Gender Egalitarianism Scale for Adolescents (KGES-A). Results: First, the gender equality consciousness of the students who took women's studies was high in the areas of educational life and socio-cultural life, and that of the subjects of grandparent families and Catholic was found to be high in the domestic life area. Second, the gender sensitivity of the subjects who took women's studies was found to be high in all sub-areas. In addition, the gender sensitivity of females was higher in the areas of sexual identity, non-violence, and self-reflection than that of males. That of 4-year college students was higher in the areas of sexual identity, openness to gender roles, and non-violence than that of 3-year college students. In addition, the gender sensitivity of Catholic students was high in the areas of sexual identity and openness to gender roles. Third, gender equality consciousness was found to have an effect depending on whether subjects took women's studies, family type, family type, and religion, and gender sensitivity was found to have an effect depending on whether subjects took women's studies or gender. Conclusion: Since dental hygienist is a profession that targets humans, education that can instill equal awareness and values of humans is important. To inspire gender sensitivity and gender equality consciousness in a prospective professional, it is necessary to conduct programs and education related to gender intelligence within dental hygiene curriculum.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권1호
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• pp.1-6
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• 2015

In this work, the combined meandering-pattern stress-sensors were presented in order to achieve the high sensitivity of stress sensors. Compared to the previous works, which have been using the single meandering-pattern stress-sensors, the sensitivity was approximately observed to increase by 30%~70%. Also, in this paper, more simple and convenient stress-measurement method was presented.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1447-1450
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• 2006

The high speed and sensitivity array test system has been developed and utilized for massproduction of advanced LTPS displays including SOG and OLED. It realizes fast enough TACT enabling 100% inspection with better than 1fF sensitivity. The result of actual measurement shows its superior TACT and sensitivity, and also shows MURA detection of OLED panel.