LSC Quenching Correction of H-3 Leached Sample of Paper Packaging Material

Changhyun Ryu,Sangyong Park,Junghwan Hong,Jusngsuk Park,Kwangpyo Kim 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2

In liquid scintillation counting, sample radioactivity is analyzed by measuring photons emitted from counting vials. Quenching effect lowers photon intensity from samples, which leads to lower counting efficiency. So an appropriate quenching correction according to characteristics of samples is important. In this study, the quenching correction for H-3 analysis was conducted according to the characteristics of paper packaging material leached samples. The leached samples are made from H-3 leaching method which is in the process of development for H-3 contamination screening. There are several ways of quenching correction such as internal standard (IS) method, quench correction curve and triple-to-double coincidence ratio (TDCR) method, etc. For quench correction curve, quenched standard set, which has the same matrix as experimental samples, is needed to be prepared. Each leached sample, however, has different matrix and color depending on condition of leaching experiment, which means that it is not capable of preparing standard set having same matrix with the samples. In this study, the counting samples are used for plotting quench correction curve instead of quenched standard set. Spectral quench parameter of the external standard [SQP(E)] is used as quench indicating parameter (QIP). TDCR and counting efficiencies determined by IS method are used as counting efficiencies. The quench curve of TDCR versus SQP(E) has R2 = 0.55 and the curve of efficiency from IS method versus SQP(E) has R2 = 0.99. TDCR is known for approximate counting efficiency, however, TDCR as counting efficiency needs careful use for H-3 analysis of leached samples. The curve used efficiency from IS method is suitable for H-3 analysis of leached samples. In this study, the quench correction curve is prepared for H-3 analysis of leached samples of paper packaging material. SQP(E), TDCR and efficiency from IS method was used as parameters to plot the quench correction curve, and, the efficiency from IS method is suitable for H-3 analysis of the leached samples. The result of this study can be used for H-3 analysis of leached samples of paper packaging material.

합성곱 신경망 기반 JPEG 압축 품질에 따른 영상 분류

류창현(Changhyun Ryu),유송현(Songhyun Yu),정제창(Jechang Jeong) 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.11

The Increased Level of Depression and Anxiety in Irritable Bowel Syndrome Patients Compared with Healthy Controls: Systematic Review and Meta-analysis

( Changhyun Lee ),( Eunyoung Doo ),( Ji Min Choi ),( Seung-ho Jang ),( Han-seung Ryu ),( Ju Yup Lee ),( Jung Hwan Oh ),( Jung Ho Park ),( Yong Sung Kim ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2017 Journal of Neurogastroenterology and Motility (JNM Vol.23 No.3

Background/Aims Irritable bowel syndrome (IBS) patients commonly experience psychiatric disorders, such as depression and anxiety. This meta-analysis sought to compare depression and anxiety levels between IBS patients and healthy controls. Methods We searched major electronic databases (PubMed, EMBASE, MEDLINE, and Cochrane library) to find comparative studies on IBS patients and healthy controls. The primary outcome was a standardized mean difference (SMD) of anxiety and depression levels; sub-group analyses were conducted according to IBS-subtypes. Results In total, 2293 IBS patients and 4951 healthy controls from 27 studies were included. In random effect analysis, depression and anxiety levels were significantly higher in IBS patients (pooled SMD = 0.76; 95% CI, 0.62-0.90; P < 0.001; I² = 77.2% and pooled SMD = 0.84; 95% CI, 0.67-1.01; P < 0.001; I² = 85.6%, respectively). Both analyses` funnel plots showed symmetry. In meta-regression analysis, heterogeneity was due to the studied region and questionnaire type for both depression and anxiety. In sub-group analyses of IBS-subtype, the pooled SMDs of depression and anxiety levels (IBS with predominant constipation: 0.83 and 0.81, IBS with predominant diarrhea: 0.73 and 0.65, and IBS with mixed bowel habits: 0.62 and 0.75; P < 0.001, respectively) were significantly higher in all IBS-subtypes. Conclusions The present meta-analysis showed depression and anxiety levels to be higher in IBS patients than in healthy controls, regardless of IBS-subtype. However, the gender effect on psychological factors among IBS patients could not be determined and should be evaluated in prospective studies. (J Neurogastroenterol Motil 2017;23:349-362)

Subwavelength Optical Resonant Cavity-Induced Enhancement of the Near-Band-Edge Emission from ZnO-Core/SnO₂-Shell Nanorods

Jin, Changhyun,Kim, Hyunsu,Ryu, Han-Youl,Kim, Hyoun Woo,Lee, Chongmu American Chemical Society 2011 The Journal of Physical Chemistry Part C Vol.115 No.17

<P>ZnO-core/SnO<SUB>2</SUB>-shell nanorods were fabricated by a two-step process: thermal evaporation of ZnO powders and atomic layer deposition of SnO<SUB>2</SUB>. Transmission electron microscopy and X-ray diffraction revealed the cores and shells of the as-prepared core–shell nanorods to be single crystal wurtzite-type ZnO and polycrystalline rutile-type tetragonal SnO<SUB>2</SUB>, respectively. Photoluminescence (PL) measurements showed that the intensity of near-band edge (NBE) emission of ZnO nanorods was enhanced significantly by the SnO<SUB>2</SUB> coating. The maximum intensity of NBE emission of the ZnO-core/SnO<SUB>2</SUB>-shell nanorods obtained with a shell layer thickness of 15 nm was ∼25 times higher than that of the ZnO nanorods. The enhancement of the NBE emission might be due to the combination of the following sources: the giant oscillator strength effect due to subwavelength optical resonant cavity formation in the nanorods, the quantum confinement of photogenerated carriers inside the ZnO cores, the suppression of visible emission and nonradiative recombination due to the formation of a depletion region in the ZnO cores, and the suppression of carrier capture by surface states. In particular, the exceptionally high NBE emission intensity for a specific shell layer thickness of 15 nm was attributed mainly to subwavelength optical resonant cavity formation.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2011/jpccck.2011.115.issue-17/jp2000514/production/images/medium/jp-2011-000514_0003.gif'></P>

Bioinspired, Calcium-Free Alginate Hydrogels with Tunable Physical and Mechanical Properties and Improved Biocompatibility

Lee, Changhyun,Shin, Jisoo,Lee, Jung Seung,Byun, Eunkyoung,Ryu, Ji Hyun,Um, Soong Ho,Kim, Dong-Ik,Lee, Haeshin,Cho, Seung-Woo American Chemical Society 2013 Biomacromolecules Vol.14 No.6

<P>Alginate hydrogels are for various biomedical applications including tissue engineering, cell therapy, and drug delivery. However, it is not easy to control swelling or viscoelastic and biophysical properties of alginate hydrogels prepared by conventional cross-linking methods (ionic interaction using divalent cations). In this study, we describe a bioinspired approach for preparing divalent ion-free alginate hydrogels that exhibit tunable physical and mechanical properties and improved biocompatibility due to the absence of cations in the gel matrices. We conjugated dopamine, a minimalized adhesive motif found in the holdfast pads of mussels, to alginate backbones (alginate-catechol) and the tethered catechols underwent oxidative cross-linking. This resulted in divalent cation-free alginate hydrogels. The swelling ratios and moduli of the alginate-catechol hydrogels are readily tunable, which is difficult to achieve in ionic bond-based alginate hydrogels. Furthermore, alginate-catechol hydrogels enhanced the survival of various human primary cells including stem cells in the three-dimensional gel matrix, indicating that intrinsic cytotoxicity caused by divalent cations becomes negligible when employing catechol oxidation for alginate cross-linking. The inflammatory response in vivo was also significantly attenuated compared to conventional alginate hydrogels with calcium cross-linking. This biomimetic approach for the preparation of alginate hydrogels may provide a novel platform technology to develop tunable, functional, biocompatible, three-dimensional scaffolds for tissue engineering and cell therapy.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/bomaf6/2013/bomaf6.2013.14.issue-6/bm400352d/production/images/medium/bm-2013-00352d_0009.gif'></P>

Self-attenuation Correction of U-235 in Metal Ingot Using MCNP and Gamma Spectroscopy

Sunwoo Lee,Changhyun Ryu,Jungsuk Park,Junghwan Hong,Jichang Ryu,Kwangpyo Kim 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

Some of the metal waste generated from KEPCO NF is being disposed of in the form of ingots. An ingot is a metal that is melted once and then poured into a mold to harden, and it is characterized by a uniform distribution of radioactive material. When measuring the uranium radioactivity in metal ingot with HPGe detector, 185.7 keV of U-235 is used typically because most gamma rays emitted at U-235 are distributed in low-energy regions below 200 keV. To analyze radioactivity concentration of U-235 with HPGe detector more accurately, self-attenuation due to geometrical differences between the calibration source and the sample must be corrected. In this study, the MCNP code was used to simulate the HPGe gamma spectroscopy system, and various processes were performed to prove the correlation with the actual values. First an metal ingottype standard source was manufactured for efficiency calibration, and the GEB coefficient was derived using Origin program. And through the comparison of actual measurements and simulations, the thickness of the detector’s dead layers were defined in all directions of Ge crystal. Additionally instead of making an metal ingot-type standard source every time, we analyzed the measurement tendency between commercially available HPGe calibration source (Marinelli beaker type) and the sample (metal ingot type), and derived the correction factor for geometry differences. Lastly the correction factor was taken into consideration when obtaining the uranium radioactivity concentration in the metal ingot with HPGe gamma spectroscopy. In conclusion, the U-235 radioactivity in metal ingot was underestimated about 25% of content due to the self-attenuation. Therefore it is reasonable to reflect this correction factor in the calculation of U-235 radioactivity concentration.

노인 성 건강의 유형과 특성에 관한 연구: 천안시를 중심으로

유지혜(JiHye, Ryu),강창현(ChangHyun, Kang) 경희대학교 인류사회재건연구원 2019 OUGHTOPIA Vol.34 No.2

본 연구는 천안시 거주 노인들의 성 건강유형을 파악하고, 성 건강 유형의 특성 탐색을 목적으로 한다. 조사대상은 천안시 노인복지관과 경로당 이용 노인 405명에게 일대일 대면 설문조사로 진행하였다. 이 중 성 활동과 성 태도의 유형별 성 건강 연구 대상자 256명을 분석하였다. 면담 대상자의 10명에 대한 개별 심층면담을 통해 통계적 결과를 보완하였다. 연구결과는 첫째, 적극적 성 활동 긍정적 성 태도를 보이는 노인들의 성 건강이 높다. 둘째, 성 건강은 유 배우자, 남성, 고 학력, 저위 연령층에서 높고, 고혈압, 당뇨의 질병은 성 건강과 유의한 차이를 보이지는 않는다. 셋째, 성 건강 높음 유형은 성 문제를 낮게 인식하고, 성 지식이 높으며, 성 욕구와 대처에서 적극적이고 이성 교제와 성 교육의 필요성에 긍정적이다. 넷째, 성 건강 낮음 유형은 성 문제를 높게 인식하고, 성 지식과 성 욕구가 낮으며, 성적 욕구를 억제한다. 이에 본 연구에서는 성 건강 유형과 그 특성을 파악하여, 성 건강을 높일 수 있는 차별화된 성교육 프로그램이 필요함을 제언한다. The purpose of this study is to identify the types of sexual health of the elderly living in Cheonan City and to explore the characteristics of each type. The research was conducted by one-on-one survey of 405 senior citizens from senior welfare centers and senior centers in Cheonan City. Among them, 256 people were analyzed for sexual health study by types of sexual activities and sexual attitudes. The statistical results were supplemented by individual in-depth interviews with 10 people among the interviewed. First of all, the sexual health of the elderly who have active sexual activities and positive sexual attitudes is high. Second, sexual health is high among one with the spouse, male, the highly educated and the low-aged, and the diseases, like high blood pressure and diabetes do not affect sexual health significantly. Third, type with high sexual health not only has high subjective health awareness, but is active in sexual desire and response, and positive for the need for romantic relationships and sex education. Fourth, the type with low sexual health is highly aware of sexual issues, has low sex knowledge and sexual desire, and tends to repress sexual desire. Thus, in this study, we propose a differentiated sex education program that can identify the characteristics of each sexual health type and improve sexual health.

군 네트워크 환경에서의 SDN 도입에 관한 연구

성창현(Seong Changhyun),유석(Ryu seok),이재용(Lee Jaiyong) 한국통신학회 2013 한국통신학회 학술대회논문집 Vol.2013 No.6

Derivation of Pyrolysis Operating Conditions for Volume Reduction of Radiation Waste

Changhwan Cho,Sungjong Kim,Changhyun Ryu,Chulhyun Hwang,Jungsuk Park 한국방사성폐기물학회 2021 한국방사성폐기물학회 학술논문요약집 Vol.2021 No.06

Effects of N-acetyl-L-cysteine on Gene Expression of Antioxidant Enzymes in Yeast Cells after Irradiation

Jin Kyu Kim,Jiyoung Park,Tae Ho Ryu,Changhyun Roh,Mohammad Nili 대한방사선방어학회 2012 대한방사선방어학회 학술발표회 논문요약집 Vol.2012 No.04