• Title/Summary/Keyword: Z - R relation

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Effect of grain crushing on 1D compression and 1D creep behavior of sand at high stresses

  • Wang, Z.;Wong, R.C.K.
    • Geomechanics and Engineering
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    • v.2 no.4
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    • pp.303-319
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    • 2010
  • The effect of grain crushing on the deformation of sand in 1D compression and 1D creep at high stresses was investigated theoretically and experimentally. An approach was proposed to formulate the process of grain crushing in sand in accordance with the laws of fracture mechanics and energy conservation. With this approach, the relation between the void ratio and the amount of grains crushed in 1D compression was derived. Laboratory test data were used to verify this derived relation. In addition, it was observed that there are similarities in evolution of grain size distribution in 1D compression and 1D creep tests. This implies that the changes in microstructure in sand under 1D compression and 1D creep are comparable.

The first five-year results of Seoul National University AGN Monitoring Project

  • Wang, Shu;Woo, Jong-Hak;Son, Donghoon;Shin, Jaejin;Cho, Hojin
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.1
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    • pp.54.4-55
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    • 2021
  • The Seoul National University AGN Monitoring Project (SAMP) is a welldesigned long-term AGN reverberation mapping project. SAMP focuses on the luminous AGNs out to z~0.5 with relative long time lags between AGN continuum and broad emission lines and aims to probe the high-end of the AGN broad line region (BLR) size-luminosity (R-L) relation. The pilot observations started in October 2015 for 100 AGNs to confirm the variability and the H and [O III] emission line strengths. Based on the initial variability test, 48 quasars has been continued spectroscopic monitoring since Feb. 2016 with Lick 3m and MDM 2.4m telescopes with a cadence of ~20 days. Supporting photometric monitoring in B and V band was conducted at multiple facilities including the MDM 1.3m, LOAO, and DOAO telescopes with a cadence of ~10 days. By the time of Feb. 2021, we have obtained five years spectroscopic and photometric data. More than 30 AGNs shows significant variability in five-year baseline and 16 of them show well detected lags between B-band and H. Here, we report some examples of SAMP light curves and lag detections using the first five-year data as well as the location of our 16 targets in the AGN BLR R-L relation. These measurements are consistent with the existing R-L relation and located at the high-end. With the coming data, SAMP are hopefully to report more AGNs with well detected lags. Our results demonstrate the general feasibility and potential of long-term reverberation project with medium cadence for luminous AGNs.

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Mediating Effect of Therapeutic Relationship with Mental Health Professionals in the Relation between Empowerment and Recovery of Community Dwelling Patients with a Mental Illnesst (지역사회 정신장애인의 임파워먼트와 회복 : 치료적 관계의 매개효과)

  • Oh, Mi-Hwa
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.4
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    • pp.211-220
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    • 2018
  • This study was conducted to identify the mediating effects of the therapeutic relationship with mental health professionals between empowerment and recovery in mental illness. The participants were 168 adults in two community mental health centers and three rehabilitation centers in Jeonbuk. The data were collected by structured questionnaires from April 15 to April 30, 2015 and analyzed using descriptive statistics, Pearson's correlation coefficient, and multiple regression analysis with the SPSS 19.0 statistical program. The mean score of empowerment for mental illness, recovery and therapeutic relationship were $60.4{\pm}10.85$, $101.8{\pm}20.70$ and $74.5{\pm}14.30$, respectively. There were significantly positive correlations between recovery in empowerment and therapeutic relationship (r=0.33, p<0.001), as well as empowerment and recovery (r=0.51, p<0.001), while there were significantly positive correlations between therapeutic relationship and recovery (r=0.55, p<0.001). Therapeutic relationship had a partial mediated effect between empowerment and recovery, which was found to be significant by the Sobel test (z=3.706, p<0.001). The results of this study can be used as basic data for development of a practical recovery-enhancing program to promote therapeutic relationships and improve empowerment in relation to therapist of the mentally disabled.

The Effects of Temperature and Strain Rate on Flow Stress and Strain of AA5083 Alloy during High Temperature Deformation (AA5083 합금의 고온 변형시 유동응력 및 연신율에 미치는 온도와 변형 속도의 영향)

  • Ko, Byung-Chul;Kim, Jong-Heon;Yoo, Yeon-Chul
    • Transactions of Materials Processing
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    • v.7 no.2
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    • pp.168-176
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    • 1998
  • Hot workability of the AA5083 alloy ws investigated by torsion test at temperature ranges of $350{\sim}520^{\circ}C$ and strain rates of 0.5, 1.0, and 3.0/sec. The flow stress and hot ductility of the AA5083 alloy as a function of deformation variables such as temperature and train rate were studied. The microstructural evolution of the AA5083 alloy was studied in relation to Zener-Hollomon parameter (Z=exp( /RT) Also the hot restoration mechanism of the AA5083 alloy was small when Z val-ues were higher than $1.73{\times}1016/sec(370^{\circ}C,\;0.5/sec)$ In addition the difference microstructures during hot deformation. It was found that the increase of flow curves and deformed microstructures during hot deformation. It was found that the increase of flow stress of the AA5083 alloy was small when Z val-ues were higher than $1.73{\times}1016/sec(370^{\circ}C.\;0.5/sec)$. However under the low Z values less than $1.73{\times}1016/sec(370^{\circ}C,\;0.5/sec)$ the flow stress increase with increasing the Z values. The large dispersoid particles in the matrix grain decreased the flow strain of the AA5083 alloy because it caused the stress concentration during hot deformation.

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CONVOLUTION SUMS OF ODD AND EVEN DIVISOR FUNCTIONS

  • Kim, Daeyeoul
    • Honam Mathematical Journal
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    • v.35 no.3
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    • pp.445-506
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    • 2013
  • Let ${\sigma}_s(N)$ denote the sum of the s-th power of the positive divisors of N and ${\sigma}_{s,r}(N;m)={\sum_{d{\mid}N\\d{\equiv}r\;mod\;m}}\;d^s$ with $N,m,r,s,d{\in}\mathbb{Z}$, $d,s$ > 0 and $r{\geq}0$. In a celebrated paper [33], Ramanuja proved $\sum_{k=1}^{N-1}{\sigma}_1(k){\sigma}_1(N-k)=\frac{5}{12}{\sigma}_3(N)+\frac{1}{12}{\sigma}_1(N)-\frac{6}{12}N{\sigma}_1(N)$ using elementary arguments. The coefficients' relation in this identity ($\frac{5}{12}+\frac{1}{12}-\frac{6}{12}=0$) motivated us to write this article. In this article, we found the convolution sums $\sum_{k&lt;N/m}{\sigma}_{1,i}(dk;2){\sigma}_{1,j}(N-mk;2)$ for odd and even divisor functions with $i,j=0,1$, $m=1,2,4$, and $d{\mid}m$. If N is an odd positive integer, $i,j=0,1$, $m=1,2,4$, $s=0,1,2$, and $d{\mid}m{\mid}2^s$, then there exist $u,a,b,c{\in}\mathbb{Z}$ satisfying $\sum_{k& lt;2^sN/m}{\sigma}_{1,i}(dk;2){\sigma}_{1,j}(2^sN-mk;2)=\frac{1}{u}[a{\sigma}_3(N)+bN{\sigma}_1(N)+c{\sigma}_1(N)]$ with $a+b+c=0$ and ($u,a,b,c$) = 1(Theorem 1.1). We also give an elementary problem (O) and solve special cases of them in (O) (Corollary 3.27).

Statistical Quality Control of Herbal Drugstuffs Distributed in Seoul Area - Centering around Ash, Acid-insoluble Ash, Loss on Drying and Hazardous Heavy Metals - (서울지역 유통한약재의 통계적 품질관리 - 회분, 산불용성회분, 건조감량, 유해중금속을 중심으로 -)

  • Kim, Dong-Gyu;Kim, Bog-Soon;Han, Chang-Ho;Kim, Eun-Ju;Choi, Byung-Hyun;Park, Seung-Kook
    • YAKHAK HOEJI
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    • v.53 no.5
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    • pp.274-280
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    • 2009
  • To survey the status of quality control of major ingredients of 'Ssanghwatang (Oriental medicine used for fatigue)', we analyzed 1,024 samples (9 kinds) of medical herbs to determine amounts of ashes, acid-insoluble ashes, loss on drying that are major elements to ensure basic quality of herbal drugstuffs. After ash analysis, Paeoniae Radix (from China) failed to meet the herbal standard criterion. After yielding Z-score(indicating the probability of exceeding its criterion) Zizyphi Fructus, Zingiberis Rhizoma, Paeoniae Radix, Rehmanniae Radix Preparata became objects of intense quality control (=IQC). Analysis on loss on drying shows Cinnamomi Cortex was unsuitable and was put under the IQC. In case of respective heavy metals, Angelicae Gigantis Radix, Cnidii Rhizoma, Cinnamomi Cortex exceeded the maximum permissible range for Cd. The 3 kinds of sub-standards were put to the IQC. Statistic figures showed a significant correlation (t-test, p<0.01) between country-of-origin and sub-quality rates. Compared to domestic one, imported medicinal herbs were less suitable in regard of acid-insoluble ash, loss on drying and Pb/Hg content. Meanwhile, amounts of Acid-insoluble ash showed positive relation with amounts of Pb (r=0.202) and As (r=0.243) among heavy metals leading to an inference that herbs of which root/rhizome is used for medical purposes attribute its high heavy metal content to the fine earth/sand being stuck to its root stalk.

KYDISC program: The Impact of Mergers on the Evolution of Galaxies

  • Oh, Sree
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.1
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    • pp.30.1-30.1
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    • 2017
  • In the hope to detect low-surface brightness features (${\mu}_{r^{\prime}}{\sim}27\;mag\;arcsec^{-2}$), we carried out KASI-Yonsei Deep Imaging Survey for Clusters (KYDISC) targeting 14 local clusters at 0.016 < z < 0.145 using Magellan/IMACS telescope and CFHT/MegaCam. Out of 1450 cluster galaxies, 18% of galaxies show the signatures of galaxy mergers. We explore merger-driven changes from various point-of-view. We first examine color-magnitude relations, and find that galaxies related to recent mergers are populated more on blue color than their counterparts. Besides, we find the extremely low frequency of mergers on low-mass red-sequence galaxies, suggesting a migration of red galaxies into the green-valley region through merger-driven star-formation. We also study the mass-size relation of our sample, finding a larger galaxy size in galaxies related to recent mergers. Our results suggest that mergers can simultaneously change properties of galaxies, making outliers on galactic scaling relations.

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The effect of irradiation mode on degree of cure, shrinkage and microleakage of composite resin restoration.

  • Park, Jong-Jin;Park, Jeong-Won;Kim, Sung-Kyo
    • Proceedings of the KACD Conference
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    • 2001.11a
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    • pp.558.2-558
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    • 2001
  • The aims of this study are (1) to investigate the relation of irradiation mode, polymerization shrinkage and degree of cure of composite resin and(2) it effect on micorleakage of class V restorations. VIP(BISCO Dental Products, Schaumburg, IL, USA) and Optilux 501 (Demetron/Kerr, Danbury, CT, USA) curing lights were used for curing Z-250 composite resin following irradiation mode: VIP 200㎽d, VIP 400㎽, VIP 600㎽, pulse-delay(200㎽ 3sec, 5min wait, 600㎽ 30sec), Optilux R mode.(omitted)

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The effect of irradiation mode on degree of cure, shrinkage and microleakage of composite resin restroation.

  • Park, Jong-Jin;Park, Jeong-Won;Kim, Sung-Kyo
    • Proceedings of the KACD Conference
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    • 2001.11a
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    • pp.555-555
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    • 2001
  • The aims of this study are (1) to investigate the relation of irradiation mode, polymerzition shrinkage and degree of cure of composite resin and (2) it effect on microliakage of calss V restorations. VIP(BISCO Dental Products, Schaumburg, IL, USA) and Optilux 501(Demetron/Kerr, Danbury, CT, USA) curing lights were used for curing Z-250 composite resin following irradiation mode: VIP 200㎽, VIP 400㎽, VIP 600㎽, pulse-delay(200㎽ 3sec, 5min wait, 600㎽ 30sec), Optilux C mode, Optilux R mode.(omitted)

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A Study on the Evaluation Methods of IRDS for Screening the Industrial Design Proposals (IRDS 시스템에 의한 디자인 컨셉트의 평가방법 연구)

  • 우흥룡
    • Archives of design research
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    • v.20
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    • pp.51-58
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    • 1997
  • This paper aims to aid a practical evaluation for screening out the design proposais under applying the IRDS system, which is developed a computer aided industrial design system as a computer application system. In this study, the author adopted 3 evaluation methods with criteria which have quantitative and qualitative attributes : the Intuitive Evaluation Methods(X), the Accumulative Evaluation Method(Y), the Benchmarking Evaluation Methods(Z). The results show that the 3 Methods have reciprocal relationships under reliability(r=0.0001). In analysis on the properties of the evaluation methods, the Evaluation Method (X) shows rapidity especially, the Evaluation Method (Y); relativity, the Evaluation Method(Z); importance respectively. The correlation analysis between the evaluation methods makes the null hypothesis denying, then we could adapt the research hypothesis. Therefore the correlation between them has positive relationship, and it shows thicker than the result of the 1st study.

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