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The influence of Ni ion addition on the microstructure and gamma ray shielding ability of ferromagnetic CuFe2O4 ceramic material

  • Mohammad W. Marashdeh;Fawzy H. Sallam;Ahmed M. Abd El-Aziz;Mohamed I. Elkhatib;Sitah f. Alanazi;Mamduh J. Aljaafreh;Mohannad Al-Hmoud;K.A. Mahmoud
    • Nuclear Engineering and Technology
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    • v.56 no.7
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    • pp.2740-2747
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    • 2024
  • The sintering process acquired ferromagnetic copper ferrite ceramic material with a small concentration of Ni ion at 1100 ℃ for 1 h. Previously, copper ferrite with Ni proportions powder was acquired by the wet chemical process according to the relation CuFe2-xNixO4 where x takes values 0.0, 0.015, 0.03, 0.04, and 0.05. The role of Ni ion in the copper ferrite structure was investigated by X-ray analysis, Scanning electron microscope, EDX analysis, and density measurements. The gamma-ray shielding properties for the fabricated CuFeNiO ceramics samples were evaluated using the Monte Carlo simulation method. The obtained results show an enhancement in the linear attenuation coefficient for the fabricated ceramics with increasing the insertions of Ni ions within the fabricated samples, where increasing the Ni ions concentration between 0 and 1.19 wt% increases the linear attenuation by between 1.581 and 1.771 cm-1 (at 0.103 MeV), 0.304-0.338 cm-1 (at 0.662 MeV), and 0.160-0.178 cm-1 (at 2.506 MeV), respectively. Simultaneously, the radiation protection efficiency for a 1 cm thickness of the fabricated samples increased between 14.8 and 16.3% with increasing the Ni ions between 0 and 1.19 wt%. Although the Ni doping concentration does not exceed 1.5 wt% of the total composition of the fabricated ceramics, the shielding capacity of the fabricated ceramics was enhanced by more than 11%, along the studied energy interval. Therefore, the fabricated samples can be used in gamma-ray shielding applications.

Effects of Microstructures on the Toughness of High Heat Input EG Welded Joint of EH36-TM Steel (EH36-TM강의 대입열 EGW 용접부 저온 인성에 미치는 미세 조직의 영향)

  • Choi, Woo-Hyuk;Cho, Sung-Kyu;Choi, Won-Kyu;Ko, Sang-Gi;Han, Jong-Man
    • Journal of Welding and Joining
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    • v.30 no.1
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    • pp.64-71
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    • 2012
  • The characteristics of high heat input (342kJ/cm) EG (Electro Gas Arc) welded joint of EH36-TM steel has been investigated. The weld metal microstructure consisted of fine acicular ferrite (AF), a little volume of polygonal ferrite (PF) and grain boundary ferrite (GBF). Charpy impact test results of the weld metal and heat affected zone (HAZ) met the requirement of classification rule (Min. 34J at 20C). In order to evaluate the relationship between the impact toughness property and the grain size of HAZ, the austenite grain size of HAZ was measured. The prior austenite grain size in Fusion line (F.L+0.1 mm) was about 350μm. The grain size in F.L+1.5 mm was measured to be less than 30μm and this region was identified as being included in FGHAZ(Fine Grain HAZ). It is seen that as the austenite grain size decreases, the size of GBF, FSP (Ferrite Side Plate) become smaller and the impact toughness of HAZ increases. Therefore, the CGHAZ was considered to be area up to 1.3mm away from the fusion line. Results of TEM replica analysis for a welded joint implied that very small size (0.81.2μm) oxygen inclusions played a role of forming fine acicular ferrite in the weld metal. A large amount of (Ti, Mn, Al)xOy oxygen inclusions dispersed, and oxides density was measured to be 4,600-5,300 (ea/mm2). During the welding thermal cycle, the area near a fusion line was reheated to temperature exceeding 1400C. However, the nitrides and carbides were not completely dissolved near the fusion line because of rapid heating and cooling rate. Instead, they might grow during the cooling process. TiC precipitates of about 50 ~ 100nm size dispersed near the fusion line.

Analysis of Fire Direction and Pine Tree Survival using to Fire Scar formed in Tree Stem after forest Fire (산불발생 후 불자국을 이용한 소나무 생존 및 지형에 따른 산불의 방향 분석)

  • 채희문;이찬용
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.5 no.1
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    • pp.30-35
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    • 2003
  • The study of the scars formed on the bark of pine trees damaged by forest fire was carried out in the burned area of Samchuk and Donghae in 2000. Fire scars were formed on the bark of trees when fire passed by the tree. Fire scarring is usually found on the windward and leeward sides of the tree. Fire spread was analyzed topographically using the fire scars formed at the tree stem. Fire spread was closely related to the shape, slope and direction of the forestland. Four fire direction types are classified according to the shapes of the forestland. The height of the fire scar was higher on the leeward side than on the windward side of the trees studied. The burnt area of the total bark of the tree was over 30% in dead trees and below 12% in living trees. The regression model of the burnt stem area using the height of the fire scar, the diameter of breast height and the height of tree was Y=-2.484×Height+0.04199×D.B.H-1.686×Windward+11.172×Leeward+23.432(r=0.936, F=409.968, P>0.0001).

Improvement of lower hybrid current drive systems for high-power and long-pulse operation on EAST

  • M. Wang;L. Liu;L.M. Zhao;M.H. Li ;W.D. Ma;H.C. Hu ;Z.G. Wu;J.Q. Feng ;Y. Yang ;L. Zhu ;M. Chen ;T.A. Zhou;H. Jia;J. Zhang ;L. Cao ;L. Zhang ;R.R. Liang;B.J. Ding ;X.J. Zhang ;J.F. Shan;F.K. Liu ;A. Ekedahl ;M. Goniche ;J. Hillairet;L. Delpech
    • Nuclear Engineering and Technology
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    • v.54 no.11
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    • pp.4102-4110
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    • 2022
  • Aiming at high-power and long-pulse operation up to 1000 s, some improvements have been made for both 2.45 GHz and 4.6 GHz lower hybrid (LH) systems during the recent 5 years. At first, the guard limiters of the LH antennas with graphite tiles were upgraded to tungsten, the most promising material for plasma facing components in nuclear fusion devices. These new guard limiters can operate at a peak power density of 12.9 MW/m2. Strong hot spots were usually observed on the old graphite limiters when 4.6 GHz system operated with power >2.0 MW [B. N. Wan et al., Nucl. Fusion 57 (2017) 102019], leading to a reduction of the maximum power capability. With the new limiters, 4.6 GHz LH system, the main current drive (CD) and electron heating tool for EAST, can be operated with power >2.5 MW routinely. Long-pulse operation up to 100 s with 4.6 GHz LH power of 2.4 MW was achieved in 2021 and the maximal temperature on the guard limiters measured by an infrared (IR) camera was about 540 ℃, much below the permissible value of tungsten material (~1200 ℃). A discharge with a duration of 1056 s was achieved and the 4.6 GHz LH energy injected into the plasma was up to 1.05 GJ. Secondly, the fully-active-multijunction (FAM) launcher of 2.45 GHz system was upgraded to a passive-active-multijunction (PAM), for which the density of optimum coupling was relatively low (below the cut-off value). Good coupling with reflection coefficient ~3% has been achieved with plasma-antenna distance up to 11 cm for the new PAM. Finally, in order to eliminate the effect of ion cyclotron range of frequencies (ICRF) wave on 4.6 GHz LH wave coupling, the location of the ICRF launcher was changed to a port that is located 157.5° toroidally from the 4.6 GHz LH system and is not magnetically connected.

High LO-RF Isolation W-band MIMIC Single-balanced Mixer (높은 LO-RF 격리 특성의 W-band MIMIC Single-balanced 믹서)

  • An Dan;Lee Bok-Hyung;Lim Byeong-Ok;Lee Mun-Kyo;Lee Sang-Jin;Jin Jin-Min;Go Du-Hyun;Kim Sung-Chan;Shin Dong-Hoon;Park Hyung-Moo;Park Hyim-Chang;Kim Sam-Dong;Rhee Jin-Koo
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.6 s.336
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    • pp.67-74
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    • 2005
  • In this paper, high LO-RF isolation W-band MIMIC single-balanced mixer was designed and fabricated using a branch line coupler and a λ/4 transmission line. The simulation results of the designed 94 GHz balun show return loss of -27.9 dB, coupling of -4.26 dB, and thru of -3.77 dB at 94 GHz, respectively. The isolation and phase difference were 23.5 dB and 180.2 at 94 GHz. The W-band MIMIC single-balanced mixer was designed using the 0.1 μm InGaAs/InAlAs/GaAs Metamorphic HEMT diode. The fabricated MHEMT was obtained the cut-off frequency(fT) of 189 GHz and the maximum oscillation frequency(fmax) of 334 GHz. The designed MIMIC single-balanced mixer was fabricated using 0.1 μm MHEMT MIMIC Process. From the measurement, the conversion loss of the single-balanced mixer was 23.1 dB at an LO power of 10 dBm. Pl dB(1 dB compression point) of input and output were 10 dBm and -13.9 dBm respectively. The LO-RF isolations of single-balanced mixer was obtained 45.5 dB at 94.19 GHz. We obtained in this study a higher LO-RF isolation compared to some other balanced mixers in millimeter-wave frequencies.

Study on the Perceived Stress Level of Mothers in Neonatal Intensive Care Unit (NICU에 입원한 미숙아 어머니의 스트레스)

  • Kim, Tae-Im
    • Journal of Haehwa Medicine
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    • v.8 no.1
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    • pp.865-878
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    • 1999
  • With advances in neonatal medicine, smaller and sicker infants are surviving premature birth. As these tiny patients battle for their lives, their parents also struggle with psychological consequences of an unexpected role. The birth of a sick infants has long been documented as stressful events for the parents. High stress levels may alter parents' interaction with their baby and impair their communication with health professionals, which can in turn affect parents' participation in care planning and decision making. Nursing interventions aimed at reducing the parental stress and anxiety levels during this crisis may have a positive impact on their ability to form an attatchment to their baby and make prudent decisions about his care. The planning of such interventions would be inhanced if the contributions of various factors to increased parental stress levels were identified. This descriptive study was conducted to understand the contents and degree of parental stress in the NICU during their premature's hospitalization, and to give a baseline data in developing nursing intervention program. Subjects were the 60 mother of hospitalized newborn in NICU of 2 University Hospital in Taejon City from April 1st, 1999 to June 30th, 1999, who agreed to take part in this study. The instrument used in this study were Parental Stressor Scales:NICU(PSS:NICU) developed by Miles et al.. and validated by 3 NICU practitioners and 3 child health nursing faculties. The questionnaire has 4 dimensions and 45 items; sight and sounds of NICU(5 items), babies' appearance and behavior nursing intervention(19 items), parental role alteration and relationship with their baby(10 items), health team communication(11 items). The questionnaire asks parents to rate each item on a five-point Likert type scale that ranges from "not stressful" (1) to "extremely stressfu1"(5). Total scores representing overall stress from the NICU environment are calculated by summing response to each item. A high score indicates high stress. A subscale score is calculated by summing the responses to each item in the subscale. Cronbach's α coefficients were .93. The data was analyzed as average, Frequency, Standard deviation, t-test, ANOVA, Pearson correlation coefficient by use of SPSS/PC+. The results of this study is summarized as follows ; 1. The total perceived stress level score of mothers of premature baby was slightly high(3.66±1.1). The highest scored dimension was 'relationship with their baby and parental role change'(4.21±0.9), and next were 'appearance and behavior of the baby'(3.92±1.1), 'communication with health team'(3.32±1.3), 'sight and sounds of NICU'(3.30±1.1). 2. There were statistically significant correlation noted ; mother's perceived severity of the baby's condition(F=8.0012, P= .0125) and baby's gestational age(r = -.4724, P = .0500). In summary, information about physical environment of NICU, the mother's perceived severity of premature baby's state, maternal role change related variables and the knowledge of characteristics of premature baby must be included in nursing intervention program of mother's of premature baby in reducing the parental stress and anxiety level. It is suggested that each NICU needs to develop a nurse managed supportive care program for parents of premature baby. Also, it is suggested that there need to investigate the coping mechanism of mother of premature baby.

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Characteristics of Groundwater Quality in Sasang Industrial Area, Busan Metropolitan City (부산시 사상공단지역의 지하수 수질 특성)

  • Hamm, Se-Yeong;Kim, Kwang-Sung;Lee, Jeong-Hwan;Cheong, Jae-Yeol;Sung, Ig-Hwan;Jang, Seong
    • Economic and Environmental Geology
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    • v.39 no.6 s.181
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    • pp.753-770
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    • 2006
  • In urban areas, groundwater pollution is heavily affected by urbanization with land use types. This study aims to characterize groundwater quality and contamination in Sasang industrial area of Busan Metropolitan City where metalworking, machinery and footwear factories are located. Busan Metropolitan City is the highest in the utilization of groundwater resources among the metropolitan cities in Korea. K+,Na+,Ca2+,Mg2+,Cl,SO24andHCO3 concentrations, and electrical conductivity (EC), total dissolved solids (TDS) and salinity are high in the areas near the Nakdong River. The results are attributed to the influence of salt water which intruded into the coastal sediments during sedimentation. In addition, the dominant chemical type of Ca-Cl indicates the influence of salt water in the geological formations as well as anthropogenic pollution. SiO2 ion is interpreted to originate from both water-silicate mineral reactions and the decomposition of cement concretes. Trichloroethylene (TCE) was detected at 12 sites of total 18 sites. However, tetrachloroethylene (PCE) was detected at f sites and 1.1.1-trichloroethane (TCA) at 3 sites. According to the factor analysis, factor 1 was explained by 49.8%, factor 2 19.8%, and factor 3 11.0% with total 80.6% explanation. pH, TDS, salinity, Ca2+,K+,Mg2+,Na+,Al3+,As3+,ClandFe2+ were positively highly loaded to factor 1. The chemical components loaded to factor 1 represent the chemical characteristics of both industrial pollution and influence by salt water. Based on the cluster analysis and distribution pattern of chemical components, the concentration of Na+,Ca2+,Cl,SO24K+,andMg2+ is high in the riverside area of the Nakdong River composed of coastal sediments that is influenced by salt water. The downstream area of the Hakjang Stream is judged to be affected by both salt water and artificial pollution. The other part of the study area is interpreted by anthropogenic pollution.

A Scientific Analysis of Ancient Pigments on Wall Paintings at Yeongsanjeon in Tongdo Temple Using a Field-XRF (휴대용X선형광분석기를 이용한 통도사 영산전 벽화 안료의 과학적 성분분석)

  • Han, Min Su;Lee, Han Hyoung;Kim, Jae Hwan
    • Korean Journal of Heritage: History & Science
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    • v.44 no.3
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    • pp.132-149
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    • 2011
  • In ancient period, a variety of inorganic or organic pigments had been used as colorants in various kinds of religious and secular paintings such as tomb paintings and wall and scroll paintings in buddhist temples, and danchung(cosmic patterns) for the surface of wooden buildings. This study discusses the results obtained from an analysis of the pigments on the wall paintings of Yeongsanjeon(Hall of Vulture Peak) in Tongdo temple by a qualitative analysis using a field-XRF. The results can be briefly summarized as follows. Firstly, assuming from the major components examined from F-XRF analysis, raw materials of pigment of each color are: red to be Cinnabar(HgS) or Hematite(Fe2O3); white to be White Lead[2PbCO3Pb(OH)2] in most cases and Calcite(CaCO3) or Chalk(CaCO3), Kaolin(Al2O3SiO24H2O) in some cases; yellow to be Yellow Ocher[FeO(OH)nH2O]; black to be carbon(C); green on the painted surface to be Celadonite[K(Mg,Fe2+)(Fe3+,Al)(Si4O10)(OH)2] in most cases; dark green on the halo of figures to be Malachite[CuCO3Cu(OH)2], Copper Green[2CuOCO2H2O] or Atacamite[Cu2Cl(OH)3]. Secondly, incarnadine and pink were made by mixing with more than two pigments such as red and white for making various tone of colors. The qualitative analysis of pigments on the wall paintings of Yeongsanjeon, in conclusion, displays that the all pigments for ancient periods are inorganis pigments. However, it has the limitation to identify a definite kinds of mineral for each pigment because it was not possible to collect samples from cultural heritage for conducting a crystalline analysis of XRD.

Synthesis, Characterization and Antimicrobial Activities of Hydrazone Ligands Derived from 2-(phenylamino)acetohydrazide and Their Metal Complexes (2-(Phenylamino)acetohydrazide로부터 유도된 Hydrzone 리간드와 그들의 착물의 합성, 특성 및 항균활성)

  • EL-Saied, F.A.;Shakdofa, M.M.E.;Al-Hakimi, A.N.
    • Journal of the Korean Chemical Society
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    • v.55 no.3
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    • pp.444-453
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    • 2011
  • VO(II), ZrO(II), Hf(IV), UO2(II), Sn(II), V(V)O3, Ru(III), Cd(II), Ho(III) and Yb(III) complexes of N'-(2-hydroxybenzyl)-2-(phenylamino)acetohydrazide (H2L1, 1) and N'-((3-hydroxy-naphthalen-2-yl)methylene)-2-(phenylamino)-acetohydrazide (H2L2, 13) have been synthesized and characterized by elemental analyses, 1H NMR, IR, UV-Vis, conductance, thermal analyses (DTA and TG). The spectral data showed that the ligands behave as neutral bidentate, monobasic bidentate, monobasic tridentate or bibasic tridentate ligand bonded to the metal ions through the azomethine nitrogen atoms, phenolic hydroxyl group in protonated or deprotonated form and enolic or ketonic carbonyl group. The ligands and their metal complexes exhibit higher antifungal and antibacterial inhibitory effects than parent ligands and the solution of metal ions. Most of metal complexes exhibit higher antifungal activity than standard antifungal drug (amphotricene B). It is also clear that the ligands and their metal complexes have higher antifungal activity than antibacterial activity.

Peroxisome proliferator-activated receptor γ is essential for secretion of ANP induced by prostaglandin D2 in the beating rat atrium

  • Zhang, Ying;Li, Xiang;Liu, Li-Ping;Hong, Lan;Liu, Xia;Zhang, Bo;Wu, Cheng-Zhe;Cui, Xun
    • The Korean Journal of Physiology and Pharmacology
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    • v.21 no.3
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    • pp.293-300
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    • 2017
  • Prostaglandin D2 (PGD2) may act against myocardial ischemia-reperfusion (I/R) injury and play an anti-inflammatory role in the heart. Although the effect of PGD2 in regulation of ANP secretion of the atrium was reported, the mechanisms involved are not clearly identified. The aim of the present study was to investigate whether PGD2 can regulate ANP secretion in the isolated perfused beating rat atrium, and its underlying mechanisms. PGD2 (0.1 to 10μM) significantly increased atrial ANP secretion concomitantly with positive inotropy in a dose-dependent manner. Effects of PGD2 on atrial ANP secretion and mechanical dynamics were abolished by AH-6809 (1.0μM) and AL-8810 (1.0μM), PGD2 and prostaglandin F2α (PGF2α) receptor antagonists, respectively. Moreover, PGD2 clearly upregulated atrial peroxisome proliferator-activated receptor gamma (PPARγ) and the PGD2 metabolite 15-deoxy-Δ12, 14-PGJ2 (15d-PGJ2, 0.1μM) dramatically increased atrial ANP secretion. Increased ANP secretions induced by PGD2 and 15d-PGJ2 were completely blocked by the PPARγ antagonist GW9662 (0.1μM). PD98059 (10.0μM) and LY294002 (1.0μM), antagonists of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) signaling, respectively, significantly attenuated the increase of atrial ANP secretion by PGD2. These results indicated that PGD2 stimulated atrial ANP secretion and promoted positive inotropy by activating PPARγ in beating rat atria. MAPK/ERK and PI3K/Akt signaling pathways were each partially involved in regulating PGD2-induced atrial ANP secretion.