Development of a micro-FID using a diffusion flame

A micro-flame ionization detector (micro-FID) was developed operating with a diffusion flame with a folded flame structure. Unlike conventional FIDs, an air-hydrogen diffusion flame was developed and tested in an encapsulated structure of Quartz-Macor??-Quartz layers. Diffusion flames are generally known to be more controllable and stable than premixed flames, which fits our purpose for the micro-FID, where the stability plays an important role for many applications. Various Macor designs including a burner cavity and a micro-channel were tested to obtain highest output sensitivity over methane test samples. In order to gauge sensitivity of the device, collected electric charge per mole (C/mol) was calculated and taken as a reference value of ionization efficiency. The result was 1.959x10-2 C/mol for methane which was about 34 times higher compared to the result obtained using a counter-flow flame, which was 5.73x10-4 C/mol for methane, while one of the commercial macro FIDs has 10-1 C/mol. This result shows that the micro-FID using the folded flame structure enhances ionization with less leakage of the analytes than the classical counter-flow flame design

Picturing a Storm Center in the Far East: Geopolitical Image and Representation of Korea in Early American Newspaper Visuals

This Capstone Project explores the image and representation of Korea in early modern American newspaper visuals during the period when Korea and the U.S. first began to engage in the late 19th and early 20th centuries. The American newspaper visuals, which interact with headlines, captions, and texts, are represented with specific patterns and features in close links to the newspaper\u27s geopolitical discourse production, specifically the “Far Eastern Question,” which was produced by western powers and Japan. The visuals were intended to show Korea as a dangerous and uncivilized place, “a storm center in the Far East.” Such geopolitical visuals in early American newspapers, which presented Korea by linking politics with geography, aided in justifying the power-competition environment of imperialist countries in the Far East and neutralize Korea\u27s independence. The geographical images and representation of Korea in American newspaper visuals served American readers to visually understand the process of Japan\u27s protectorate of Korea. This project, which navigates the image and representation of early modern Korea, implies the origin of today’s Korean geopolitical images in U.S. media

Analyzing Norm Violations in Live-Stream Chat

Toxic language, such as hate speech, can deter users from participating in online communities and enjoying popular platforms. Previous approaches to detecting toxic language and norm violations have been primarily concerned with conversations from online forums and social media, such as Reddit and Twitter. These approaches are less effective when applied to conversations on live-streaming platforms, such as Twitch and YouTube Live, as each comment is only visible for a limited time and lacks a thread structure that establishes its relationship with other comments. In this work, we share the first NLP study dedicated to detecting norm violations in conversations on live-streaming platforms. We define norm violation categories in live-stream chats and annotate 4,583 moderated comments from Twitch. We articulate several facets of live-stream data that differ from other forums, and demonstrate that existing models perform poorly in this setting. By conducting a user study, we identify the informational context humans use in live-stream moderation, and train models leveraging context to identify norm violations. Our results show that appropriate contextual information can boost moderation performance by 35\%.Comment: 17 pages, 8 figures, 15 table

Highly efficient and robust noble-metal free bifunctional water electrolysis catalyst achieved via complementary charge transfer

The operating principle of conventional water electrolysis using heterogenous catalysts has been primarily focused on the unidirectional charge transfer within the heterostructure. Herein, multidirectional charge transfer concept has been adopted within heterostructured catalysts to develop an efficient and robust bifunctional water electrolysis catalyst, which comprises perovskite oxides (La0.5Sr0.5CoO3-delta, LSC) and potassium ion-bonded MoSe2 (K-MoSe2). The complementary charge transfer from LSC and K to MoSe2 endows MoSe2 with the electron-rich surface and increased electrical conductivity, which improves the hydrogen evolution reaction (HER) kinetics. Excellent oxygen evolution reaction (OER) kinetics of LSC/K-MoSe2 is also achieved, surpassing that of the noble metal (IrO2), attributed to the enhanced adsorption capability of surface-based oxygen intermediates of the heterostructure. Consequently, the water electrolysis efficiency of LSC/K-MoSe2 exceeds the performance of the state-of-the-art Pt/C||IrO2 couple. Furthermore, LSC/K-MoSe2 exhibits remarkable chronopotentiometric stability over 2,500h under a high current density of 100mAcm(-2). While water electrolysis offers a renewable means to obtain H-2, it is necessary to understand the roles adopted by catalytic components. Here, authors explore a heterostructured MoSe2/perovskite oxide catalyst that shows multidirectional charge transfer to boost electrocatalytic water splitting

CT-free quantitative SPECT for automatic evaluation of %thyroid uptake based on deep-learning

Purpose Quantitative thyroid single-photon emission computed tomography/computed tomography (SPECT/CT) requires computed tomography (CT)-based attenuation correction and manual thyroid segmentation on CT for %thyroid uptake measurements. Here, we aimed to develop a deep-learning-based CT-free quantitative thyroid SPECT that can generate an attenuation map (μ-map) and automatically segment the thyroid. Methods Quantitative thyroid SPECT/CT data (n = 650) were retrospectively analyzed. Typical 3D U-Nets were used for the μ-map generation and automatic thyroid segmentation. Primary emission and scattering SPECTs were inputted to generate a μ-map, and the original μ-map from CT was labeled (268 and 30 for training and validation, respectively). The generated μ-map and primary emission SPECT were inputted for the automatic thyroid segmentation, and the manual thyroid segmentation was labeled (280 and 36 for training and validation, respectively). Other thyroid SPECT/CT (n = 36) and salivary SPECT/CT (n = 29) were employed for verification. Results The synthetic μ-map demonstrated a strong correlation (R2 = 0.972) and minimum error (mean square error = 0.936 × 10−4, %normalized mean absolute error = 0.999%) of attenuation coefficients when compared to the ground truth (n = 30). Compared to manual segmentation, the automatic thyroid segmentation was excellent with a Dice similarity coefficient of 0.767, minimal thyroid volume difference of − 0.72mL, and a short 95% Hausdorff distance of 9.416mm (n = 36). Additionally, %thyroid uptake by synthetic μ-map and automatic thyroid segmentation (CT-free SPECT) was similar to that by the original μ-map and manual thyroid segmentation (SPECT/CT) (3.772 ± 5.735% vs. 3.682 ± 5.516%, p = 0.1090) (n = 36). Furthermore, the synthetic μ-map generation and automatic thyroid segmentation were successfully performed in the salivary SPECT/CT using the deep-learning algorithms trained by thyroid SPECT/CT (n = 29). Conclusion CT-free quantitative SPECT for automatic evaluation of %thyroid uptake can be realized by deep-learning.Key points Question 1: Can CT-free attenuation correction be realized for SPECT? Pertinent findings: The first deep-learning algorithm produced μ-map similar to CT-derived μ-map. Implications for patient care: Quantitative SPECT can be performed without CT. Therefore, patients can be protected from redundant radiation exposure of CT. Question 2: Can the thyroid be segmented without high-resolution images like CT? Pertinent findings: The second deep-learning algorithm successfully generated the thyroid segmentation map using low-resolution images such as the generated μ-map and SPECT. Implications for patient care: The thyroid segmentation process was dramatically reduced from 40–60min to < 1min, facilitating rapid patient care. Question 3: Can quantitative SPECT/CT be possible without CT? Pertinent findings: The two deep-learning algorithms deprived the quantitative thyroid SPECT/CT of CT. Implications for patient care: Repetitive CT acquisitions may be excluded in multiple SPECT/CT-based nuclear imaging studies, such as dosimetry

Patient Health Questionnaire-9, Body Mass Index, Household Income According to Sleep Duration: Findings From a Community Health Survey

Background and Objective Research on the relationship between sleep duration and Patient Health Questionnaire-9 (PHQ-9), body mass index (BMI), and income in South Korea was scarce. This study aimed to investigate the relationship between sleep duration and the PHQ-9, BMI, and household income. Methods We used data from the Korean Community Health Survey (KCHS) conducted by the Korean Center for Disease Control and Prevention in 2018 which included a total of 228340 participants from across the country. We divided the participants into four groups based on their sleep duration and used one-way analysis of variance (ANOVA) to compare the mean values of PHQ-9, BMI, and household income among the groups. Results A total of 227899 respondents were included in the study. Based on a one-way ANOVA, the mean PHQ-9 score tended to increase as sleep duration decreased. However, the group with a sleep duration of 9 hours or more had an exceptionally higher mean PHQ-9 score than the group with a sleep duration of 7 to 9 hours. The BMI score generally decreased as the sleep duration increased. Additionally, the group with a sleep duration of 5 to 7 hours and 7 to 9 hours had higher household income than the group with a sleep duration of 5 hours or less or 9 hours or more. Conclusions This study demonstrated the association between sleep duration and PHQ-9, BMI, and household income. Sleep duration was found to be a factor influencing PHQ-9, BMI, and household income

A Structure of Optical See-Through Head Mounted Display

In the paper, we suggest the optical see-through head mounted display (OST-HMD) for self-contained augmented reality (AR) environment. In the OST-HMD system, several types of optical architectures such as microprojector, spatial light modulator (SLM), diffraction optical elements (DOE), polarized beam splitter (PBS) are used. For comfortable use, HMDs should have small size, light weight, better mobility, no screen door effect, and minimum burden on skin. Technologically HMDs should provide higher resolution, less latency, wider field of view (FOV), wider color gamut, sufficient refresh rate, reliable eye tracking method and higher pixel per degree (PPD). Existing HMDs use optical combiners in front of projection optics, which reduce the visibility of the real-world and thus harm the sense of realistic interaction with the surronding world. Instead of the front optical combiner, we used transparent projection optics, PBS, and SLM for better view of the environment through the optical components and they enhanced the sense of reality in interaction with objects in the environment. We also used the pinhole array structure to increase FOV and resolution. To interact with the surronding world in AR, we adopted the 6 degrees of freedom (6DOF) microelectromechanical system inertial measurement unit (MEMS IMU) in the center of the HMD and created a depth map of real objects using time of flight (TOF) method. Figure 1. shows the concept of OST-HMD (left of Figure. 1) and the optical structure in the paper. (right of Figure. 1). We suggested the OST-HMD optical structure with transparent projection optics and MEMS IMU, which increased real-world visibility and the sense of presense. We will further improve the performance and simplify the structure by using ray tracing and image processing methods.1

높은 몰입감 제공을 위한 조도 전환형 혼합현실 전용 강의실 설계

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Development and experimental analysis of a micro-flame ionization detector for portable gas chromatographs

A portable micro-FID has been developed that utilized a diffusion flame encased in a micro-fabricated SOI structure. The micro-flame was fueled by a portable electrolyzer that provided the hydrogen and oxygen flow rates necessary for the device operation. The micro-FID was able to detect organic analytes with sensitivity that competes with the one of large-scale devices. A first major accomplishment was the encasement of a stable diffusion flame inside a quartz-silicon-quartz sandwich structure. Several micro-burner configurations were tested by varying the angle between the oxidizer and the hydrogen gas of silicon channels. The final design employed a diffusion flame that was encapsulated inside a 750 µm thick silicon channel. When the streams of oxidizer and hydrogen met at a 150° angle, a single folded flame structure with low flame strain was obtained that minimized analyte loss. The effect of channel geometry on flame structure was explored using the ANSYS FLUENT computational fluid dynamics (CFD) software package in order to compute the reactive flow in a two-dimensional geometry that simulated the micro-burner channels. Hydroxyl radical (OH) mass fraction distributions were computed as an indicator of the high-temperature zone of the flame. Also, the two-dimensional flow-field was computed in order to determine the strain rate on the non-premixed flamelet, which was used in order to rationalize flame structure. It was determined from the simulation that an angle of convergence between the channels around 150°-160° provided the least analyte loss as well as relatively low strain rates. In order to verify this experimentally, two different channel configurations, a folded flame channel design (150° angle) and a counter-flow channel design (180° angle) were tested and compared. Methane gas was injected in the hydrogen stream and the resulting ion current was measured. The folded flame channel design produced about 34 times stronger signals compared to the counter-flow channel design. The micro-FID that was based on this configuration had a linear response. In order to improve signal strength and reduce fuel consumption rate, an oxygen stream was added to the air stream and the overall channel width size was reduced to 50%. Additionally, reducing the dead volume of the injection port and introducing anchor points to the channels improved the overall device performance. These modifications allowed reducing the overall fuel consumption and improved the sensitivity by a factor of about three. In order to increase the sensitivity of the device, not only was the signal strength improved, but also efforts were made to reduce the noise. To this end, channels were fabricated with silicon-on-insulator wafers and the entire micro-FID was tested inside a Faraday cage. These modifications suppressed the noise by a factor of 43 and improved the overall sensitivity and the minimum detection level. Furthermore, it enabled the instrument to detect a mixture of 17 different gas compounds. The fuel flow rate was varied in order to determine the flow conditions that optimized flame stability and resulted in increased signal-to-noise ratio. Results showed that the highest signal-to-noise ratio was achieved with an air flow of 45 ml/min, a hydrogen flow of 26 ml/min, and an oxygen flow of 13 ml/min. Finally, the saturation voltage of the electrodes was determined in order to avoid unnecessary charge to the battery during operation and it was shown to be very closely equal to 100 V

ND3extD3 ext{D}^{3} QNet: Noisy dueling‐double‐deep q‐network for reconfigurable intelligent surfaces

Abstract Low‐cost passive reconfigurable intelligent surfaces that provide coverage expansion in wireless communication networks are facing challenges in phase shift optimization due to limitations in acquiring channel information for sub‐channels. To overcome this, a new approach that improves both the convergence speed and overall performance relative to the existing state‐of‐the‐art scheme is proposed. Experimental results in an environment with a Rician factor of 20 showed a 9.3% increase in the average sum data rate, and the probability of the sum data rate exceeding the threshold of 10 increased by 30%