Preparation of Si(Al)ON Precursor Using Organoaluminum Imine and Poly (Phenyl Carbosilane), and the Compositional Change of the Film with Different Heat Treatment Condition

Lee, Yoonjoo,Shin, Dong-Geun,Kwon, Woo Teck,Kim, Soo Ryong,Kim, Younghee The Korean Ceramic Society 2015 한국세라믹학회지 Vol.52 No.4

Si(Al)ON precursor was synthesized by formation of new Si-N bond using organoaluminum imine and liquid type poly(phenyl carbosilane). It was decomposed between $200-600^{\circ}C$, and the ceramic yield was 51% after pyrolysis. 150 - 200 nm in thickness of coating film was obtained by spin coating method. The precursor was easily oxidized during process because it was unstable in air. However the oxygen content was limited to 0.5 - 0.7 to silicon in heat treatment step. Even though the content of nitrogen was decreased by pyrolysis, Al-N and Si-N bonds were formed in ammonia atmosphere, and Si(Al)ON film was formed with 0.2 in content to silicon.

KLT-based adaptive entropy-constrained quantization with universal arithmetic coding

Yoonjoo Lee,Moo Young Kim IEEE 2010 IEEE transactions on consumer electronics Vol.56 No.4

<P>For flexible speech coding, a Karhunen-Loève Transform (KLT) based adaptive entropy-constrained quantization (KLT-AECQ) method is proposed. It is composed of backward-adaptive linear predictive coding (LPC) estimation, KLT estimation based on the time-varying LPC coefficients, scalar quantization of the speech signal in a KLT domain, and superframe-based universal arithmetic coding based on the estimated KLT statistics. To minimize the outliers both in rate and distortion, a new distortion criterion includes the penalty in the rate increase. Gain adaptive step size selection and bounded Gaussian source model also cooperate to increase the perceptual quality. KLT-AECQ does not require either any explicit codebook or a training step, thus KLT-AECQ can have an infinite number of rate-distortion operating points regardless of time-varying source statistics. For the speech signal, the conventional KLT-based classified vector quantization (KLT-CVQ) and the proposed KLT-AECQ yield signal-to-noise ratios of 17.86 and 26.22, respectively, at around 16 kbits/s. The perceptual evaluation of speech quality (PESQ) scores for each method are 3.87 and 4.04, respectively<SUP>.</SUP></P>

Low-Delay Entropy-Constrained Vector Quantization Robust Against Source Mismatch Problem

Yoonjoo Lee,Moo Young Kim 한국정보통신학회 2010 2016 INTERNATIONAL CONFERENCE Vol.3 No.1

Effect of carbon on the growth of TaC crystal derived from organometallic precursors

Lee Yoonjoo,Kang Philjae,정수용,Bae Seonggun,김정일,Lee Manyoung,Shin Dong-Geun 한국세라믹학회 2021 한국세라믹학회지 Vol.58 No.1

TaC, which is an ultra-high-temperature structural material, was derived from two types of organometallic precursors: Me 3 CCH = Ta(CH 2 CMe 3 ) 3 and Cp*-TaMe 4 . Both compounds are kinds of single-source precursors composed only of tantalum, carbon, and hydrogen, which should be converted into carbide material without oxygen contamination. The carbide material was formed through several processes such as pyrolysis, nucleation, and crystal growth, which are dependent on heat treatment temperature. However, organometallic precursor usually leaves residual carbon, and the crystallization of carbide is aff ected by the carbon. In this study, two types of organometallic precursors containing diff erent amounts of carbon in the organic part were used to prepare TaC, and the crystallization behavior of TaC in rich carbon was investigated. The amount of residual carbon was estimated by thermogravimetry (TG) analysis, and the TaC crystals were characterized using X-ray diff raction (XRD) and transmission electron microscopy (TEM). Nano-sized TaC particles were obtained by heat treatment without any by-products but with excess carbon. The TaC crystal was formed starting from 1300 °C, but the crystals grew better with less carbon, while the carbon barrier prevented agglomeration of the atoms.

Hepcidin Level Is a Prognostic Factor for Patients with Advanced NSCLC Receiving Immune Checkpoint Inhibitors

( Yoonjoo Kim ),( Jeong Eun Lee ),( Eunso Lee ),( Ock-hwa Kim ),( Jae Young Moon ),( Sun-young Yoon ) 대한결핵 및 호흡기학회 2023 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.136 No.0

Tri-iodothyronine (T3) as a Prognostic Factor for Patients with Advanced NSCLC Receiving Immune Checkpoint Inhibitors

( Yoonjoo Kim ),( Jeongsuk Koh ),( Seongdae Woo ),( Songi Lee ),( Dahyun Kang ),( Dongil Park ),( Chaeuk Chung ),( Jeongeun Lee ) 대한결핵 및 호흡기학회 2021 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.129 No.-

Introduction Endocrine hormones such as thyroxine and estrogen are known to influence the tumor progression and response to treatment. Despite the importance of ICIs (immune checkpoint inhibitors) in the treatment of advanced NSCLC, few studies have explored the effects of endocrine hormones on NSCLC receiving ICI therapy. Biomarkers like PD-L1 expression in the tumor have been developed to predict the treatment response to ICI. However, only several markers have been clinically verified using standard measurement techniques. We investigated the effects of baseline endocrine hormones in advanced NSCLC on ICI treatment and discovered an easily measurable and useful predictor. Method 156 patients with advanced NSCLC who received PD-1/PD-L1 inhibitors, excluding those with positive driver mutations, were retrospectively analyzed. We collected their clinical information and baseline laboratory findings including endocrine hormones, cytokines, CBC parameters, blood chemistry panels from peripheral blood. We identified the relationship between endocrine hormones and clinical outcomes (OS, PFS, best response), liver metastasis, and other blood markers. Result Shorter PFS was independently associated with liver metastasis, higher cortisol, lower Hb, while shorter OS was associated with liver metastasis, lower T3, higher LDH, lower albumin. According to T3 level, a newly found predictor, patients were divided into two groups, and patients with low T3 levels exhibited shorter PFS, OS, and worse best response. And we confirmed a significant association between the low T3 level and liver metastasis, a negative predictive marker for the treatment response of ICI in NSCLC. Conclusion This study shows that the baseline T3 level, relatively underrated in its clinical importance, is associated with the prognosis and response to ICIs in advanced NSCLC. The specific mechanism is probably related to the decreased function of the liver and the systemic inflammation induced by the interaction with other biomarkers such as IL-6, ACTH, cortisol, C-peptide, Hb, LDH, albumin.

Inverse Association between Platelet-Lymphocyte Ratio and Prognosis in Terminally Ill Cancer Patients: A Preliminary Study

Lee, Yoonjoo,Kim, Ye Won,Park, Dong Kyun,Hwang, In Cheol Mary Ann Liebert 2017 Journal of palliative medicine Vol.20 No.5

Childbirth and Changes in Women’s Perceptions of Their Economic Living Conditions and Attitudes Toward Social Welfare

( Yoonjoo Lee ) 사단법인 아시아문화학술원 2021 인문사회 21 Vol.12 No.1

본 연구의 목적은 출산으로 여성의 경제적 생활수준에 대한 인식과 사회복지에 대한 태도가 어떻게 변화하는지 살펴보는 것이다. 연구문제에 대한 답을 구하고자 한국복지패널 제1차년도, 제4차년도, 그리고 제7차년도 자료를 이용하였다. 최종 표본은 조사에 두 번 이상 참여했고 조사 기간 동안 동거하는 자녀가 없거나 첫 번째로 참여한 조사에서는 동거하는 자녀가 없었으나 이후 조사에서 1명 이상 생긴 것으로 확인된 만 18-44세 여성 1,082명이었다. 자료는 고정효과 회귀모델을 적용해 분석하였다. 연구결과는 다음과 같다. 첫째, 출산으로 여성은 현재 경제적 생활수준을 부정적으로 평가하게 되었다. 둘째, 출산과 여성의 미래 경제적 생활수준에 대한 인식의 변화는 유의한 관계가 나타나지 않았다. 셋째, 출산으로 여성은 미래에 조세 및 사회복지 수준이 높은 사회에 대해 더 우호적인 태도를 갖게 되었다. 본 연구결과는 여성의 경제적 생활수준에 대한 인식을 개선하고 사회복지 및 조세수준이 높은 사회를 위해서 출산 및 양육과 관련된 지원이 확대될 필요가 있음을 시사한다. The purpose of this study is to investigate how childbirth changes women’s perceptions of their economic living conditions and attitudes toward social welfare. To address these research questions, the first, fourth, and seventh waves of the Korean Welfare Panel Study were used. The final sample consisted of 1,082 women aged between 18 to 44 years who participated in two or more surveys and who did not have a coresident child throughout the surveys’ duration or who did not have a child at the time they were first surveyed but had one or more coresident children at the time they were subsequently surveyed. The data were modeled using fixed effects regression models. The results are as follows: First, childbirth changed women’s perceptions of their current economic living conditions in a negative way. Second, childbirth was not significantly associated with changes in women’s perceptions of their future economic living conditions. Third, childbirth was significantly associated with women’s more favorable attitudes toward social welfare expansion and tax increases in the future. The results suggest that more support for childbirth and childcare is needed to improve women’s perceptions of their economic conditions and to build a society with higher social welfare and taxation.

Deep Learning-based Classification of Respiratory Sounds and Its Clinical Value

( Yoonjoo Kim ),( Jeongsuk Koh ),( Seongdae Woo ),( Songi Lee ),( Dahyun Kang ),( Dongil Park ),( Jeongeun Lee ),( Sungsoo Jung ),( Chaeuk Chung ) 대한결핵 및 호흡기학회 2021 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.129 No.-

Introduction Auscultation of respiratory sound is a non-invasive and relatively simple diagnostic method that can be performed anytime, but the information provided is quite useful. Breath sound information markedly improves the accuracy of diagnosis and monitoring of disease status. Despite these advantages, auscultation has a major limitation, subjectivity. Since the interpretation of respiratory sounds requires significant expertise and clinical experience, doctors in training sometimes misidentify respiratory sounds. To overcome such a drawback, we developed an automated classification system of respiratory sounds. Method 2840 respiratory sounds were recorded by a digital stethoscope in a real clinical setting. Three pulmonologists classified them and 1918 sounds including normal sounds, crackles, wheezes, rhonchi were selected. We applied deep learning convolutional neural network (CNN) to identify the classified database. We developed the predictive model for respiratory sound classifcation combining pretrained image feature extractor of series, respiratory sound, and CNN classifer. To evaluate the accuracy of human auscultation ability and compare it with our predictive model, 70 participants were asked to listen to classified sounds and identify them. Result Deep learning-based classification model detected abnormal sounds with an accuracy of 86.5% and the AUC of 0.93. It further classifed abnormal lung sounds into crackles, wheezes, or rhonchi with an overall accuracy of 85.7% and a mean AUC of 0.92. Meanwhile, the accuracy of human auscultation was different depending on the group; 60.3% for medical students, 53.4% for interns, 68.8% for residents, and 80.1% for fellows. Conclusion This respiratory sound classification model using deep learning is expected to complement the limitation of inaccurate auscultation of clinicians and help the rapid diagnosis and appropriate treatment of respiratory diseases. In addition, this model will be useful to meet the current medical demands such as non-face-to-face care due to COVID-19 and telemedicine in hard-to-reach area.

Effects of asperities and organic-inorganic interactions on the strength of nacre-mimetic composites

Lee, Yoonjoo,Kim, Bo-Yeon,Shin, Dong-Geun,Kim, Soo-Ryong,Kwon, Woo-Teck,Kim, Younghee Elsevier 2017 Materials Science and Engineering C Vol.71 No.-

<P>Nacre is a natural organic-inorganic hybrid composite, whose hierarchical structure has a complex influence on its high strength. Many structural features have been discovered, which influence the mechanical properties of nacre, and the authors have a particular interest in the role of the asperities and organic-inorganic interactions. In this study, a composite was prepared which mimics the asperity structure using clay minerals. Organic-inorganic bonding was induced with silane treatment. Both factors increased the yield strength of the composites; however, different deformation behavior was exhibited. It was found that asperities improved the strength of the composite, and that composition influences the stiffness of the composite. The organic-inorganic interaction between the resin and the other components of the composite reduced the deformation of the composite and consequently improved strength. (C) 2016 Published by Elsevier B.V.</P>