The X-Pt(X=Ge, Cr) Underlayer Thickness Effect on Magnetic Properties of L1₀ FePt Films

J. L. Tsai,Y. C. Lin,C. J. Hsu,C. W. Hsu,S. K. Chen,W. C. Chang 한국자기학회 2007 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

서울시 지하철 구내의 공기중 분진 농도에 관한 연구

백남원(N.W. Paik),박두용(D.Y. Park),장익선(I.S. Chang),신용철(Y.C. Shin),이정인(J. l. Lee) 한국환경보건학회 1988 한국환경보건학회지 Vol.14 No.2

Airborne dust and asbestos fiber concentrations were determined in subway stations located in Seoul area. Two stations, such as Eulchiro 4.Ka Station of Une #2, constructed during a period of 1980-1984 and Hyehwa Station of Une #4, opened in 1985, were selected. The results of the study are as follows. 1. Daily tirne.weighted average (1W A) concentrations of airborne dusts from 07:00 to 20:00 hours in Line #2 and μne #4 were 0.43:t0.08 mg/m3 and 0.37:t0.12 mg/m3 , respectively. Thus, the dust levels in Líne #2 were significant1y higher than the levels in Line #4( p < 0.05). 2. Dust levels in the morning (07:00-11:00 hours), noon (1 1:00-16:00 hours) and in the evening (1 6:00-20:00 hours) in Líne #2 were 0.47:t0.17 mgjm3 , 0.37:t0.08 mg/m3 , and 0.46土0.07 mg/m3 respectively. Thus, dust levels in the morning and evening (i.e., during rush hours) were significantly higher than levels in the noon ( p < 0.02). However, there was no such difference in dust levels by time in Líne #4. 3. Airborne total dust concentrations were well below the occupational health standard of 10 mg/m3 , however, the levels were exceeding the ambient air standard recommended by the Korean Environment Administration. 4. All of airborne asbestos fiber concentrations were equal to or below 0.005 fibers/cc. The levels are within both occupational health standards and U .S. EPA criterìa. 5. A consideration should be given to the improvements of c1eaning methods (such as use of vacuum c1eaning instead of brushing) and the existing ventilation (such as more aìr change and filtration of supply air) for a reduction of dust levels. 6. It is recommended that routine monitoring of aìrborne dusts and asbestos fibers be conducted because more dusts and asbestos fibers can be produced in the aìr due to the deterioration of facilities by age and water damage in future.

Local electronic structure of Mn dopants in ZnO probed by resonant inelastic x-ray scattering

Chang, G S,Kurmaev, E Z,Jung, S W,Kim, H-J,Yi, G-C,Lee, S-I,Yablonskikh, M V,Pedersen, T M,Moewes, A,Finkelstein, L D IOP Pub 2007 Journal of physics, an Institute of Physics journa Vol.19 No.27

<P>The electronic structure of Mn dopants in ZnO epitaxial thin films synthesized at different temperatures has been investigated using resonant inelastic x-ray scattering. The resulting Mn L<SUB>2,3</SUB> x-ray emission spectra of Zn<SUB>0.8</SUB>Mn<SUB>0.2</SUB>O (resonantly excited at L<SUB>2</SUB> and L<SUB>3</SUB> absorption edges) reveal different spectral features depending on the growth temperature of the films. The relative integral intensity ratio of Mn L<SUB>2</SUB> to Mn L<SUB>3</SUB> emission lines is greatly suppressed in the case of nonmagnetic Zn<SUB>0.8</SUB>Mn<SUB>0.2</SUB>O grown at 700 °C due to L<SUB>2</SUB>L<SUB>3</SUB>M<SUB>4,5</SUB> Coster–Kronig transitions. The ferromagnetic sample grown at 600 °C exhibits a normal oxide structure. The results suggest that a high growth temperature causes direct Mn–Mn bonds from the segregation of Mn atoms in ZnO. Therefore the disappearance of ferromagnetism in Mn-doped ZnO can be attributed to antiferromagnetic Mn–Mn exchange interactions due to the inhomogeneous local environment around the Mn impurities.</P>

건국 우유와 유제품의 소비성향에 관한 조사연구

임종우,김종우,조광호,김영주,유제현,윤여창,장주익,권일경,안효일,이용규,이부응,박종래,이헌종 경상대학교 축산진흥연구소 1989 畜産振興硏究所報 Vol.16 No.1

Biogenic reductive preparation of magnetic inverse spinel iron oxide nanoparticles for the adsorption removal of heavy metals

Lingamdinne, L.P.,Chang, Y.Y.,Yang, J.K.,Singh, J.,Choi, E.H.,Shiratani, M.,Koduru, J.R.,Attri, P. Elsevier 2017 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.307 No.-

The accumulation of heavy metal ions in living cells impairs the organ function of living creatures. So, needs to develop new materials with high efficiency of heavy metals removal from the environment. As part of this effort, here, synthesized magnetic inverse spinel iron oxide nanoparticles (MISFNPs) using a biogenic methodology. To synthesize the biogenic MISFNPs, we used the seed extract of Cnidiummonnieri (L.) Cuss (CLC) as a precursor. The prepared MISFNPs was characterized using PXRD, FT-IR, SEM-EDX, SEM, BET, AFM and XPS. We also investigated the size, surface area, structure and magnetic properties of MISFNPs. Additionally, magnetic property measurement system (MPMS) studies show that our prepared MISFNPs was superparamagnetic at room temperature. Further, we used the MISFNPs for the removal of Pb(II) and Cr(III) from aqueous solutions through batch studies. Batch adsorption studies revealed that Pb(II) and Cr(III) follow pseudo-second-order kinetics during adsorption onto the homogenous surface of MISFNPs. Besides, we also found that the adsorption of Pb(II) and Cr(III) on nanoparticles followed an endothermic process. Lastly, we concluded that MISFNPs synthesized by a green route is capable of recycling and removal of heavy metals without loss of its stability.

A new approach for turn-on fluorescence sensing of L-DOPA

Wang, L.,Su, D.,Berry, S.,Lee, J.,Chang, Y. T. Royal Society of Chemistry 2017 Chemical communications Vol.53 No.92

<P>A novel design strategy for the fluorescence sensing of L-DOPA is reported. Resa-Sulf displays a significant turn-on fluorescence response to L-DOPA due to its reduction properties; this sensing mechanism was fully confirmed by mechanistic studies. Furthermore, Resa-Sulf was successfully utilized to quantitatively detect L-DOPA concentrations from a commercially available source.</P>

最近世

鄭昌烈(J?ng Chang-ry?l) 역사학회 1987 역사학보 Vol.116 No.-

Assessment of transboundary ozone contribution toward South Korea using multiple source-receptor modeling techniques

Choi, K.C.,Lee, J.J.,Bae, C.H.,Kim, C.H.,Kim, S.,Chang, L.S.,Ban, S.J.,Lee, S.J.,Kim, J.,Woo, J.H. Pergamon Press ; Elsevier [distribution] 2014 Atmospheric environment Vol.92 No.-

Ozone concentrations in East Asia were simulated using the Community Multi-scale Air Quality (CMAQ) model, and its source contributions were estimated by multiple source-receptor modeling techniques. To study relationships between ozone concentrations and precursor emission sources, three approaches were applied to four months (January, April, July, and October 2009) to represent seasonal characteristics and compare results, with a particular focus on South Korea. Brute force (BF) is a traditional sensitivity analysis method used to estimate model output response to an input change. The high-order decoupled direct method (HDDM), a computational method, is an efficient and accurate alternative to the BF method for sensitivity. The Ozone and Particulate Precursor Tagging Methodology (OPTM) provides contribution information quantified by tracking emissions from selected sources throughout the simulation period. The approaches generally show that most of the receptor regions were substantially influenced by emissions from central China, which is the largest anthropogenic emissions source region in East Asia. Local emissions were still major contributors, especially South Korea and Japan during July 2009. On the other hand, a case study of maximum 8-h ozone concentrations derived from CMAQ-OPTM on April 9 in South Korea shows that the NO<SUB>x</SUB> and VOCs emissions from China contributed approximately 82% and 91%, respectively, to maximum 8-h ozone in Region 4 (South Korea) without boundary inflow, which indicates that Chinese emissions are the dominant contributor in this episode. A comparison study of the three approaches shows that HDDM tends to estimate biogenic source contributions lower than that from OPTM in China but similar to OPTM in South Korea and Japan. When comparing the BF method and HDDM, the sensitivity results show a reasonably good agreement during a given period. The location- and time-dependent maximum 8-h ozone isopleths over South Korea as a receptor region created by HDDM suggest that most ozone was being transported from central China, whereas almost no ozone was formed locally during April 2009, and local conditions were heavily VOC limited. On the other hand, local emissions were the dominant contributor during July 2009, and every source region showed a NO<SUB>x</SUB>-limited regime, which indicates that ozone concentrations in South Korea strongly depend on NO<SUB>x</SUB> emissions during this month.

철근콘크리트 실험체의 시스템 식별과 유한요소 모델 수정

김학진(Kim, H.J.),유은종(Yu, E.J.),김호근(Kim, H.G.),장극관(Chang, K.K.),이상현(Lee, S.H.),조승호(Cho, S.H.),정란(Chung, L.) 한국소음진동공학회 2008 한국소음진동공학회 논문집 Vol.18 No.7

This paper focused on the application of finite element model updating technique to evaluate the structural properties of the reinforced concrete specimen using the data collected from shaking table tests. The specimen was subjected to six El Centre (NS, 1942) ground motion histories with different peak ground acceleration (PGA) ranging from 0.06 g to 0.50 g. For model updating, flexural stiffness values of structural members (walls and slabs) were chosen as the updating parameters so that the converged results have direct physical interpretations. Initial values for finite element model were determined from the member dimensions and material properties. Frequency response functions (i.e. transfer functions), natural frequencies and mode shapes were obtained using the acceleration measurement at each floor and given ground acceleration history. The weighting factors were used to account for the relative confidence in different types of Inputs for updating (j.e. transfer function and natural frequencies) The constraints based on upper/lower bound of parameters and sensitivity-based constraints were implemented to the updating procedure in this study using standard bounded variable least-squares(BVLS) method. The veracity of the updated finite element model was investigated by comparing the predicted and measured responses. The results indicated that the updated model replicates the dynamic behavior of the specimens reasonably well. At each stage of shaking, severity of damage that results from cracking of the reinforced concrete member was quantified from the updated parameters (i.e. flexural stiffness values).

소아 쭈쭈가무시병환자 28명의 임상상 및 유병기간에 따른 간접면역형광항체가의 변동상

박병규,오영균,윤희상,염명걸,유한욱,김재형,강환섭,김익상,장우현,김승환 대한감염학회 1993 감염 Vol.25 No.2

During the autumn of 1990 , we had investigated the clinical featuresw and followed the change in the direct immunofluorescent antibody(IFA) titers in 28 children with scrub typhus who resided in or near Chinju, Korea. All the children except one were diagnosed by the peak IFA titers of 1:160 or higher. The results were as follows: 1) The clinical features of our children were not different, to a large degree, from those of adults ever described in Korea literatures. But the frequence rates of skin rash, eschar and conjunctival injection were higher, those of proteinuria and hematuria were lower than those in adults and the characters of rash in our children were also quite different(faces were frequently the first site of eruption and even palms and soles were involved occasionally, initial bright red color of rash was changed into brown color during the acute phase). 2) IFA titers rose rapidly during the 2nd or 3rd week of illness and then formed plateau. When we suggest IFA titers of 1:180 or higher as the diagnostic criteria, the seropositivity of our children was 5/7(75%) in the 1st week and over 95% in the 2nd through 5th week of illness, and suggest IFA titers of 1:160 or higher,then the seropositivityin the 1st, 2nd and 3rd through 5th week were 3/7(43%), 23/31(74%) and over 95%,respectively. 3) IFA titers in 6-8 months after disease onset were 1:80(13 children) or 1:20( 7 children), and in one and half year (our longest follow-up period), 1:20 (3 children) showing that IFA lasts longer than one and half year after sickness. 4) From the above data (3) and the fact that majority of cases of scrub typhus occur in the autumn season in Korea, IFA titers of 1:40-1:160 should be used as the diagnostic criteria in order to distinguish between the present and past infections.