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In situ gamma-ray spectrometry in the environment using dose rate spectroscopy
Ji, Y.Y.,Kim, C.J.,Chung, K.H.,Choi, H.Y.,Lee, W.,Kang, M.J.,Park, S.T. Pergamon 2016 Radiation physics and chemistry Vol.119 No.-
<P>In order to expand the application of dose rate spectroscopy to the environment, in situ gamma-ray spectrometry was first conducted at a height of 1 m above the ground to calculate the ambient dose rate and individual dose rate at that height, as well as the radioactivity in the soil layer for the detected gamma nuclides from the dose rate spectroscopy. The reliable results could be obtained by introducing the angular correction factor to correct the G-factor with respect to incident photons distributed in a certain range of angles. The intercomparison results of radioactivity using ISOCS software, an analysis of a sample taken from the soil around a detector, and dose rate spectroscopy had a difference of < 20% for Pb-214, Bi-214, Ac-228, Bi-212, Tl-208, and K-40, except for Pb-212 with low-energy photons, that is, < 300 key. In addition, the drawback of using dose rate spectroscopy, that is, all gamma rays from a nuclide should be identified to accurately assess the individual dose rate, was overcome by adopting the concept of contribution ratio of the key gamma ray to the individual dose rate of a nuclide, so that it could be accurately calculated by identifying only a key gamma ray from a nuclide. (C) 2015 Elsevier Ltd. All rights reserved.</P>
Ji, Y. Y.,Kim, C. J.,Lim, J. M.,Kim, H.,Chung, K. H. Springer Science + Business Media 2016 Accreditation and quality assurance Vol.21 No.6
<P>The validation of a method for the indirect quantification for U-238, Ra-226, and Th-232 activity and the direct quantification for K-40 activity using gamma-ray spectrometry was performed in view of consistency, reliability, and accuracy of the results. The gas tightness of Al containers used to confine the radon gas was verified from the establishment of the secular equilibrium between Ra-226 and its indicator. To evaluate validation parameters such as linearity, range, and accuracy, it was important to verify the equilibrium state of the reference materials (RM) for U and Th, because the ingrowth of progenies in the uranium decay series can affect the quantification of Ra-226 activity even if based on a certified reference material (CRM), while the ingrowth of Ra-228 from the thorium decay series should be secured in order to use Ac-228 as an indicator of Th-232. In addition, the ruggedness of the method regarding different materials was checked using two kinds of CRM, namely bauxite as an example of a raw material and coal fly ash as a by-product.</P>
Putative spin liquid in the triangle-based iridate Ba3IrTi2O9
Lee, W.-J.,Do, S.-H.,Yoon, Sungwon,Lee, S.,Choi, Y. S.,Jang, D. J.,Brando, M.,Lee, M.,Choi, E. S.,Ji, S.,Jang, Z. H.,Suh, B. J.,Choi, K.-Y. American Physical Society 2017 Physical Review B Vol.96 No.1
<P>We report on thermodynamic, magnetization, and muon spin relaxation measurements of the strong spin-orbit coupled iridate Ba3IrTi2O9, which constitutes a distinct frustration motif made up of a mixture of edge- and corner-sharing triangles. In spite of a strong antiferromagnetic exchange interaction of the order of 100 K, we find no hint for long-range magnetic order down to 23 mK. The magnetic specific heat data unveil T-linear and T-squared dependences at low temperatures below 1 K. At the respective temperatures, the zero-field muon spin relaxation features a persistent spin dynamics, indicative of unconventional low-energy excitations. A comparison to the 4d isostructural compound Ba3RuTi2O9 suggests that a concerted interplay of compasslike magnetic interactions and frustrated geometry promotes a dynamically fluctuating state in a triangle-based iridate.</P>
PLMN계 세라믹스의 유전 및 전기적 특성에 관한 연구
지승한,이능헌,김용혁,김진수,이희규,이덕출 경북대학교 센서기술연구소 1995 센서技術學術大會論文集 Vol.6 No.1
In this paper Dielectric and polarizable properties of 0.9Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.1PbTiO_(3) Ceramics have been investigated as a addition of the amount of La_(2)O_(3)(0≤x≤0.05). The Temperature-dependant electrostictive characteristics of 0.9PMN-0.1PT relaxor ferroelectic system were improved by enhencing the extent of the diffuse phase transition(DPT). This was achieved using PMN-PTceramics by the partial substitution of La at the Pb site. The curie temperature and the maximum dielectic permittivity decreased by substituting La and the electic field-related hysteresis phenomena decreased with increasing La substitution amount.
100X110μm² micro mirror array의 제작과 실험
지창현,정석환,신종우,김용권,최범규,안세진 경북대학교 센서기술연구소 1995 센서技術學術大會論文集 Vol.6 No.1
A 100 x110μm^(2) aluminum micro structure is fabricated using thick photoresist as sacrificial layer and mold for nickel electroplating. The micro structure is composed of aluminum plate, hinge, nickel support post, and address electrode. The aluminum plate is overhung about 10 μm above the silicon substrate supported by two nickel posts. The hinge connects the aluminum plate and the support post and works as a torsional spring. We used thick PR as 10 μm thick sacrificial layer and nickel electroplating mold and electroplated nickel for 10 μm high post. The aluminum plate is actuated by electrostatic force between the aluminum plate and the address electrode. The aluminum micro structure is finally released by reactive ion etching (RIE) using O_(2). The micro mirror is actuated at 35V.
β-cyclodextrin 을 이용한 난황의 콜레스테롤 제거
박우문,유익종,지중룡,전기홍,김천제,임상빈 한국축산학회 1997 한국축산학회지 Vol.39 No.5
This study was carried out to remove cholesterol from liquid egg yolk by using β-cyclodextrin(β-CD) which formed insoluble complex by binding with cholesterol existed in oil-water interface of egg yolk. The conditions of treatment varied with the centrifugal force, mixing temperature, mixing time, distilled ratio and β-CD : cholesterol molar ratio, and the removal efficiency of cholesterol of each treatment was measured. The optimal conditions of centrifugal force, mixing temperature and mixing time to remove β-CD. cholesterol complex were 2,000 g, 35℃ and 15 min, respectively. The ratio of egg yolk to distilled water was 1 : 3 with the most cholesterol removal and with the highest solid content remained. When the molar ratios of β-CD to the egg yolk cholesterol were 3: 1, 5: 1 and 6: 1, the efficiencies of cholesterol removal were 75.0, 88.9 and 95.9%, respectively, and the contents of remnant solid were 68.2, 64.6 and 56.9%, respectively. As the amount of added β-CD increased, cholesterol removal efficiency was increased but valuable nutrients of egg yolk also decreased. Therefore, it was concluded that the molar ratio of 3 : 1 -5 : 1 for β-CD : cholesterol was most effective in removing cholesterol from egg yolk, considering the amount of valuable components remained.
Hoetzenecker, Wolfram,Echtenacher, Bernd,Guenova, Emmanuella,Hoetzenecker, Konrad,Woelbing, Florian,Br체ck, J체rgen,Teske, Anna,Valtcheva, Nadejda,Fuchs, Kerstin,Kneilling, Manfred,Park, Ji-Hyeon,Kim, K Nature Publishing Group, a division of Macmillan P 2012 Nature medicine Vol.18 No.1
Sepsis, sepsis-induced hyperinflammation and subsequent sepsis-associated immunosuppression (SAIS) are important causes of death. Here we show in humans that the loss of the major reactive oxygen species (ROS) scavenger, glutathione (GSH), during SAIS directly correlates with an increase in the expression of activating transcription factor 3 (ATF3). In endotoxin-stimulated monocytes, ROS stress strongly superinduced NF-E2??related factor 2 (NRF2)??dependent ATF3. In vivo, this ROS-mediated superinduction of ATF3 protected against endotoxic shock by inhibiting innate cytokines, as Atf3<SUP>??/??</SUP> mice remained susceptible to endotoxic shock even under conditions of ROS stress. Although it protected against endotoxic shock, this ROS-mediated superinduction of ATF3 caused high susceptibility to bacterial and fungal infections through the suppression of interleukin 6 (IL-6). As a result, Atf3<SUP>??/??</SUP> mice were protected against bacterial and fungal infections, even under conditions of ROS stress, whereas Atf3<SUP>??/??</SUP>Il6<SUP>??/??</SUP> mice were highly susceptible to these infections. Moreover, in a model of SAIS, secondary infections caused considerably less mortality in Atf3<SUP>??/??</SUP> mice than in wild-type mice, indicating that ROS-induced ATF3 crucially determines susceptibility to secondary infections during SAIS.