Downsizing gas sensors based on semiconducting metal oxide: Effects of electrodes on gas sensing properties

Song, Young Geun,Shim, Young-Seok,Kim, Sangtae,Han, Soo Deok,Moon, Hi Gyu,Noh, Myoung Sub,Lee, Kwangjae,Lee, Hae Ryong,Kim, Jin-Sang,Ju, Byeong-Kwon,Kang, Chong-Yun Elsevier Sequoia 2017 Sensors and actuators. B Chemical Vol.248 No.-

<P><B>Abstract</B></P> <P>We report the highly sensitive and selective downsized gas sensors for the IoT application. Sensing areas of Pt-interdigitated electrodes (IDEs) were varied to investigate the relation between sensing materials and electrodes. In<SUB>2</SUB>O<SUB>3</SUB> nanocolumns were deposited on the pre-patterned Pt IDEs using glancing angle deposition (GLAD). The effect of the interface resistance between electrodes and sensing materials, and the intergrain resistance between nanocolumns is analyzed by linear regression at different sensing area and incident angle of GLAD. In<SUB>2</SUB>O<SUB>3</SUB> (angle: 85°, sensing area: 0.3mm×0.3mm) nanocolumns with double Schottky barriers show the highest response and selectivity with fast response time of 10s to VOCs among the samples fabricated in this study. The analysis reveals that the intrinsic response of In<SUB>2</SUB>O<SUB>3</SUB> (angle: 85°, sensing area: 0.3mm×0.3mm) nanocolumns are dominantly affected by intergrain resistance, resulting in a high response. Our demonstration for the fundamental aspect of downsizing gas sensor makes an important contribution to the chemical sensor field with broad interest.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The sensing areas are varied to investigate the relation between sensing materials and electrodes. </LI> <LI> The effect of the interface resistance and the intergrain resistance are analyzed by linear regression. </LI> <LI> The performance of the downsizing gas sensor is greatly influenced by the interface resistance. </LI> </UL> </P>

Versatile approaches to tune a nanocolumnar structure for optimized electrical properties of In₂O₃ based gas sensor

Han, Soo Deok,Noh, Myoung-Sub,Kim, Sangtae,Shim, Young-Seok,Song, Young Geuon,Lee, Kwangjae,Lee, Hae Ryung,Nahm, Sahn,Yoon, Seok-Jin,Kim, Jin-Sang,Kang, Chong-Yun Elsevier 2017 Sensors and actuators. B, Chemical Vol.248 No.-

<P><B>Abstract</B></P> <P>In this study, we demonstrate tuning of electrical properties and sensing responses of In<SUB>2</SUB>O<SUB>3</SUB> nanocolumnar structure via varying glancing angle (GLAD) deposition conditions by e-beam evaporator. The varied deposition conditions include glancing angle, vacuum level and deposition rate. The electrical property of In<SUB>2</SUB>O<SUB>3</SUB> nanostructured thin films, demonstrated by the base resistance, change up to 3 orders of magnitude from 110Ω to 103104Ω depending on the porosity of nanocolumnar structure and oxygen vacancy concentration. This variation in electrical property transfers to the tuning of gas sensing response, and we achieve tuning the same material (In<SUB>2</SUB>O<SUB>3</SUB>) based gas sensors to better perform for specific type of gases (either oxidizing or reducing). The highest responses achieved in this work reached up to 176 for oxidizing gases (5ppm NO<SUB>2</SUB>, R<SUB>gas</SUB>/R<SUB>air</SUB>) and 929 for reducing gases (50ppmC<SUB>2</SUB>H<SUB>5</SUB>OH, R<SUB>air</SUB>/R<SUB>gas</SUB>). Therefore, we demonstrate that gas sensors can be optimized for specific type of target gases with the same material, via simple control of deposition conditions. Along with the high reproduciblility and sensitivity, this puts the nanocolumnar thin film based gas sensors by GLAD with huge potential for further miniaturization and mass production, suitable for the upcoming IoT era.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nanocolumnar In<SUB>2</SUB>O<SUB>3</SUB> thin film based gas sensor is fabricated by glancing angle deposition (GLAD). </LI> <LI> Electrical properties of In<SUB>2</SUB>O<SUB>3</SUB> can be optimized for specific target gases, tuning simple deposition conditions of GLAD. </LI> <LI> In<SUB>2</SUB>O<SUB>3</SUB> sensors have excellent performances with high repeatability, recovery, and extremely low detection limit. </LI> </UL> </P>

Gamma-Ray Susceptibility of Immature and Mature Hippocampal Cultured Cells

SONG, Myoung-Sub,KIM, Joong-Sun,YANG, Miyoung,KIM, Sung-Ho,KIM, Jong-Choon,PARK, Soo Hyun,SHIN, Taekyun,MOON, Changjong Japanese Society of Veterinary Science 2010 The Journal of veterinary medical science Vol.72 No.5

<P>Ionizing radiation suppresses neurogenesis in the mammalian brain. This <I>in vitro</I> study compared the detrimental effect of acute gamma-irradiation on immature hippocampal cells with mature cells. Both rat immature (0.5 day <I>in vitro</I> (DIV)) and mature hippocampal cells (14 DIV) were irradiated with 0-4 Gy gamma-rays. Cell viability was analyzed by using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay. DNA fragmentation study was performed by extracting intracellular DNA. Morphological features of apoptosis were characterized by 4',6-diamidine-2'-phenylindole, dihydrochloride (DAPI) staining. MTT assay revealed that the survival rate of immature hippocampal cells declined in a dose-dependent manner within the range of irradiation applied, but was not changed in mature cells. Intranucleosomal DNA fragmentation in a ladder like pattern was dose-dependently increased in immature cells, but not in mature cells. The number of apoptotic nuclei in immature cells increased significantly in a dose-dependent manner within the range of irradiation applied. Active caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP) expressions in immature hippocampal cells at 6 hr after 2 Gy exposure were markedly higher than control levels. The significantly greater radiosensitivity of immature hippocampal cells than that of the mature cells, indicates that the susceptibility of such hippocampal cells depends on their maturation. In addition, gamma-irradiation may induce caspase-dependent apoptosis in immature hippocampal cells.</P>

프로그래밍 전후 순서도 비교 학습

송명섭 ( Myoung-sub Song ),김영식 ( Youngsik Kim ) 한국컴퓨터교육학회 2018 한국컴퓨터교육학회 학술발표대회논문집 Vol.23 No.1

4차 산업혁명으로 프로그래밍 교육이 중요시 되고 있으며, 2015 개정 교육과정을 통해 초·중학교에서 소프트웨어 교육이 필수 교과목으로 지정되고 소프트웨어 교육이 강화되고 있다. 2015 개정 교육과정에서는 프로그래밍 교육을 통해 문제해결력, 컴퓨팅 사고력을 함양하고자 한다. 프로그래밍 교육은 프로그램 개발자를 기르는 과정이 아니라 컴퓨팅 사고력을 함양하고자 하는 과정이므로 코딩작업보다 문제를 분석하고 알고리즘 설계부분이 더욱 더 중요하다. 프로그래밍 과정에서 순서도를 이용해 알고리즘 설계하고 작성된 순서도와 코드를 활용해 나타낸 순서도를 비교하여 오류를 검증하고 수정하는 작업에서 학습자가 느끼는 인지부담을 완화하고 효과적인 프로그래밍 교육 방법에 대해 알아보고자 한다.

Kobuvirus in South Korean black goats

Lee, Myoung-Heon,Jeoung, Hye-Young,Lim, Ji-Ae,Song, Jae-Young,Song, Dae-Sub,An, Dong-Jun Springer-Verlag 2012 Virus genes Vol.45 No.1

국내 우주 중점기술 개발 동향 (Ⅱ) - 스페이스파이오니어사업 중심으로

송복섭(Song, Bok-sub),석병석(Suk, Byong-suk),박신무(Park, Shin-mu),심영주(Shim, young-joo),용상순(Yong, Sang-soon),유명종(Yu, Myoung-jong) 한국항공우주연구원 2023 항공우주산업기술동향 Vol.21 No.2

스페이스파이오니어사업(′21∼′30)은 국가 우주전략기술을 자립화하고 원천기술을 확보하고 국가 우주기술 역량향상 및 우주산업 생태계 선순환 기반을 마련한다는 목표로 추진되고 있다. 2021년부터 2030년까지 약 10년간 발사체(3), 위성본체(7), 위성탑재체(6) 분야의 총 16개 우주중점기술을 선정하고 개발하여, 사업 목표인 세부과제 연구개발성과물의 각 연계대상 체계(다목적/차세대/정지궤도 위성 및 소형발사체 등) 연계하고자 한다. 2023년 9월 발사체 3개, 위성본체 7개, 위성탑재체 4개 과제로 14개 과제가 진행 중으로 본 논문에서는 스페이스파이오니어사업에서 진행 중인 우주중점기술 개발 현황에 대해 기술하고자 한다. Space Pioneer Program(′21∼′30) began at March 2021 in order to develop space key technology. The program was specially designed not only try to develop space key technology successfully but also to apply each results to actual domestic space projects. Currently total 14 projects are working now and they are consist of 3 projects for launch vehicle, 7 projects for satellite BUS and 4 projects for satellite payload. The most satellite projects try to overcome or substitute export control issue. And most launch vehicle projects try to develop key technology essential to small launch vehicle. This paper introduces the development status and technical performance of each projects.

Effect of donor-specific antibodies and panel reactive antibodies in living donor liver transplant recipients

Seung Hwan Song,Myoung Soo Kim,Jung Jun Lee,Man Ki Ju,Jae Geun Lee,Juhan Lee,Jin Sub Choi,Gi Hong Choi,Soon Il Kim,Dong Jin Joo 대한외과학회 2015 Annals of Surgical Treatment and Research(ASRT) Vol.88 No.2

Purpose: Preformed circulating donor-specific antibodies (DSAs) immunologically challenge vascular endothelium and the bile duct. However, the liver is an immune-tolerant organ and can avoid immunological challenges. This study was undertaken to analyze the effects of DSAs after adult living donor liver transplantation (LDLT). Methods: We retrospectively reviewed 219 LDLT patients’ records treated at our center. Results: Of the 219 patients, 32 (14.6%) were DSA (+) and 187 (85.4%) were DSA (?). Class I DSAs were present in 18 patients, class II in seven patients, and both in seven patients. Seven patients (3.2%) showed DSA to HLA-A, four (1.8%) to HLA-B, seven (3.2%) to HLA-DR, and 14 (6.4%) to two or more HLAs. More DSAs were observed in female recipients than male recipients in the DSA (+) group. The DSA (+) group showed significantly higher levels of class I and II panel reactive antibody (PRA) than did the DSA (?) group. No significant intergroup differences were found between incidences of primary nonfunction, acute rejection, vascular complication, or biliary complication. There were no significant differences in graft survival rates between the two groups. However, the recipients with multiple DSAs tended to have more acute rejection episodes and events of biliary stricture and lower graft survival rates than did patients in the DSA (?) group. Conclusion: In LDLT, the presence of multiple DSAs and high PRA seemed to be associated with poor graft outcomes, although our results did not reach statistical significance. Large cohort studies are necessary to clarify the impact of DSA and PRA in LDLT.

Amifostine ameliorates recognition memory defect in acute radiation syndrome caused by relatively low-dose of gamma radiation

이해준,김중선,Myoung-Sub Song,Heung-Sik Seo,양미영,김종춘,조성기,신태균,문창종,김성호 대한수의학회 2010 JOURNAL OF VETERINARY SCIENCE Vol.11 No.1

This study examined whether amifostine (WR-2721) could attenuate memory impairment and suppress hippocampal neurogenesis in adult mice with the relatively low-dose exposure of acute radiation syndrome (ARS). These were assessed using object recognition memory test, the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay, and immunohistochemical markers of neurogenesis [Ki-67 and doublecortin (DCX)]. Amifostine treatment (214 mg/kg, i.p.) prior to irradiation significantly attenuated the recognition memory defect in ARS, and markedly blocked the apoptotic death and decrease of Ki-67- and DCX-positive cells in ARS. Therefore, amifostine may attenuate recognition memory defect in a relatively low-dose exposure of ARS in adult mice, possibly by inhibiting a detrimental effect of irradiation on hippocampal neurogenesis.

대구지역 경부선 철도주변의 소음실태와 특성

민경섭,송희봉,박연준,한개희,이명숙,김용혜,홍성희,권기홍 한국환경과학회 1997 한국환경과학회지 Vol.6 No.1

We investigated and analysed the actual conditions and characteristics of railroad noise levels for 17 sites in the vicinity of the Seoul-Pusan Line. The results are summarized. as follows : 1) Railroad noise level ranged to 64∼74 L_eq dB(A) at day time and ranged to 60∼72 L_eq dB(A) at night time. 2) Increased night noise level depend on the increase of trains passing at night time. 3) The major factor of increased noise level in the vicinity of stations are using loudspeakers and stream whistle on trains. 4) Decreased effect of noise according to distance is able to be described quantitatively using regression equations of multiplicative model. L_eq=78.59 X^-0.056 n=25, r=-0.994, s.e.=1.007 P_av =105.68X^-0073, n =25, r =-0.997, s.e. = 1.007 Also increased and decreased effect of noise according to floor in apartment is able to be described quantitatively using regression equations of multiplicative model. L_eq = 64.238 X^0.0567, n = 39, r = 0.787, s. e. = 1.004 P_av. = 79.963 X^0.0254 n = 39, r = 0.689, s. e. = 1.056 5) Average noise level in high floor is over 70L_eq dB(A) at day and night time, so more detailed soundproofing countermeasured in high floors apartment is required.

The Role of Curative Intent Surgical Resection for the Recurrent HCC

( Seung Hwan Song ),( Jee Youn Lee ),( Su-kyung Kwon ),( Juhan Lee ),( Jae Geun Lee ),( Dai Hoon Han ),( Gi Hong Choi ),( Jin Sub Choi ),( Myoung Soo Kim ),( Soon Il Kim ),( Dong Jin Joo ) 대한간학회 2016 춘·추계 학술대회 (KASL) Vol.2016 No.1

Aims: Liver transplantation (LT) is one of the best treatment for hepatocellular carcinoma. However, there could be HCC recurrence in around 10-20% of the transplant patients. The Recurrent Hapatocellular carcinoma (HCC) after liver transplantation remains one of the major causes to graft failure and patient death. Because HCC recurrence is known for systemic disease, systemic therapy may be considered. However the optimal treatment of recurrent HCC is not established. The aim of this study is to evaluate the difference of graft survival rate between palliative therapy and curative intent surgical therapy after LT. Methods: A total 292 recipients with HCC who underwent liver transplantation between January 2007 and April 2015 in Severance hospital were retrospectively reviewed. Among 292 patients, 41 patients developed hepatic or extra-hepatic recurrent HCC. We compared the outcomes of the recurred patients according to the therapeutic approaches. Results: The mean age of the HCC recurrence group was younger than non-recurrence group (51.4 ± 6.3 vs 54.8 ± 6.9, p<0.003). There was no significant difference of the etiology of HCC between the groups. The patients above Milan criteria showed a higher tumor recurrence rate than those within Milan criteria(Odd ratio 4.717, p<0.001). The curative intent surgical therapy was performed in 13 patients. Among them, resection only in 2, adjuvant chemotherapy after resection in 4, adjuvant radiation therapy (RT) in 4, adjuvant transarterial chemoembolization (TACE) and chemotherapy in 1, adjuvant TACE and RT in 1, and adjuvant TACE and RFA in 1 case. The palliative therapy was consisted of TACE, chemotherapy, or RT. Among the patients received curative intent surgical therapy, 3 patients had intrahepatic recurrence and 10 patients had extrahepatic recurrence. The 5 year graft survival was higher in curative intent surgical therapy group than in palliative therapy group (51.1% vs 306%, P=0. 026). Conclusions: The curative intent surgical therapy showed the superior graft survival than palliative therapy. The curative intent surgical therapy is not applicable in every recurrent case. However the patient received curative intent therapy if possible, it is increased with the graft survival significantly.