• Journal of the Korean Chemical Society
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• v.60 no.5
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• pp.321-326
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• 2016

Two new polymeric complexes, [Zn(dpa)(pyz)_0.5]_n (1; dpa = diphenate and pyz = pyrazine) and [Mn₃(bpdc)₃(py)₄]_n (2; bpdc = biphenyl-4,4'-dicarboxylate and py = pyridine) were successfully isolated by the hydro- and solvo-thermal technique, respectively. The complexes were characterized by elemental and thermal analysis, vibrational IR spectroscopy, and by single crystal x-ray structure determination. For 2, magnetic property was also investigated. Complex 1 is a two-dimensional layer structure consisting of a paddle-wheel building unit of Zn-dpa chains bridged by pyrazine. While, complex 2 consists of linear trimeric Mn3 cluster as building unit to form 3D network. In the complexes, dpa²⁻ (1) and bpdc²⁻(2) ligands show a typical bis-monodendate bridging and two kinds of bridging modes; a typical bridging and chelating/bridging mode, respectively.

• IE interfaces
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• v.25 no.3
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• pp.309-318
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• 2012

Forecasting probability or likelihood of technology development success has been a crucial factor for critical decisions in technology management such as R&D project selection and go or no-go decision of new product development (NPD) projects. This paper proposes an analytic network process (ANP) approach to forecasting of technology development success. Reviewing literature on factors affecting technology development success has constructed the ANP model composed of four criteria clusters : R&D characteristics, R&D competency, technological characteristics, and technological environment. An alternative cluster comprised of two elements, success and failure is also included in the model. The working of the proposed approach is provided with the help of a case study example of MRAM (magnetic random access memory) technology.

• Journal of the Korean Magnetics Society
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• v.6 no.2
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• pp.117-121
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• 1996

육각판상 Ba-ferrite의 stacking 현상은 자성도료의 도포 후 자장배향를 행할 때 일어나는 것으로 알려져 있으나 분말의 건식분쇄시에도 일어났다. Edge mill을 사용하여 건식분쇄할 때 치환형 Ba-ferrite 분말의 보자력과 tap density는 거의 비례적으로 증가하였고, 분쇄시간보다는 가해지는 압력에 크게 의존하였다. 이 때 보자력의 증가원인은 분쇄시 생성되는 입자간의 stacking 현상에 기인된 것임을 투과전자현미경 관찰로부터 확인하였다. 분말의 tap density가 증가함에 따라 tape에서 분산초기의 광택도가 크게 감소되어 분산성은 떨어졌으나, 배향도는 tap density 1.3 g/$cm^{3}$에서 최대를 나타내었다. 과도한 건식분쇄에 의해 생성된 강고한 stacked cluster는 자성도료 제조시 분산성과 배향도를 동시에 떨어뜨리는 역할을 함을 알 수 있었다.

• Journal of The Korean Astronomical Society
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• v.48 no.2
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• pp.155-164
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• 2015

In Kang (2015) we calculated the acceleration of cosmic-ray electrons at weak spherical shocks that are expected to form in the cluster outskirts, and estimated the diffuse synchrotron radiation emitted by those electrons. There we demonstrated that, at decelerating spherical shocks, the volume integrated spectra of both electrons and radiation deviate significantly from the test-particle power-laws predicted for constant planar shocks, because the shock compression ratio and the flux of inject electrons decrease in time. In this study, we consider spherical blast waves propagating through a constant density core surrounded by an isothermal halo with ρ ∝ r⁻ⁿ in order to explore how the deceleration of the shock affects the radio emission from accelerated electrons. The surface brightness profile and the volumeintegrated radio spectrum of the model shocks are calculated by assuming a ribbon-like shock surface on a spherical shell and the associated downstream region of relativistic electrons. If the postshock magnetic field strength is about 0.7 or 7 µG, at the shock age of ∼ 50 Myr, the volume-integrated radio spectrum steepens gradually with the spectral index from α_inj to α_inj + 0.5 over 0.1–10 GHz, where α_inj is the injection index at the shock position expected from the diffusive shock acceleration theory. Such gradual steepening could explain the curved radio spectrum of the radio relic in cluster A2266, which was interpreted as a broken power-law by Trasatti et al. (2015), if the relic shock is young enough so that the break frequency is around 1 GHz.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.64-72
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• 2007

Under the AE methods, the valid condition analysis and evaluation the leak etc, resulted by the AE signal pattern on the bottom plate of ground tank at full. In next more, the gradient of accumulation amplitude distribution analysis and comparison the energy, count, and duration time that noise of EMI signal were removed. EMI signal showed height-energy, count, and duration time, it also appeared great gradient of accumulation distribution. Then, with the pure remaining AE signals cluster analysis and location. It would possibly assume of damage with corrosion. Total cluster 20 and energy showed between the maximum 11,990 and 8,565 which is much lower than above figure and event number showed from 8 to 5. Even when it difficult to certify damage by open, as it is raised higher height-sensitivity and threshold by 60 dB. It would possibly presume of location source more accurately.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.846-853
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• 1995

In order to study electronic structures for locally disordered systems, we have developed a first-principle self-con-sistent-spin-polarized real space band method (TB-LMTO-R), which combines the tight-binding(TB) linear-muffin-tin orbital(LMTO) band rrethod and the recursion(R) rrethod. The TB-LMTO-R rrethod has been applied to fer-romagnetic bec Fe, hcp Co, and fcc Ni. With varying cluster sizes, recursion coefficients, and the order of the TB-Hamiltonian, we have calculated the local density of states(LDOS) and magnetic moments. It is found that the calculation with 5,000 atoms cluster, 40 continued fractions, and the second-order TB-Hamiltonian yields a conver¬gent result in agreement with those from the conventional LMTO. In this way, we have demonstrated a physical transparency of the TB-LMTO-R method as a real space description.

• Korean Journal of Biological Psychiatry
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• v.19 no.2
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• pp.77-83
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• 2012

Objectives : Although there have been studies that examine sex differences of the brain structures using magnetic resonance imaging, studies that specifically investigate cerebellar structural differences between men and women are scarce. The purpose of current study was to examine sex differences in structures of the cerebellum using cerebellar template and cerebellum analysis methods. Methods : Sixteen men and twenty women were included in the study. A MATLAB based program (MathWorks, Natick, MA, USA), Statistical Parametric Mapping 5 (SPM5) using the spatially unbiased infra-tentorial atlas template (SUIT) as the cerebellum template, was used to analyze the brain imaging data. Results : There was no significant difference in age between men (mean age=28.1) and women (mean age=27.2). Men showed higher gray matter density than women in two left cerebellar areas including the clusters in the lobules IV and V (a cluster located across the lobules IV and V), and the lobule VIIIb (lobules IV and V, t=4.75, p<0.001 ; lobule VIIIb, t=3.08, p=0.004). Conclusions : The current study found differences in cerebellar gray matter density between men and women. The current study holds its significance for applying the template specifically developed for the analysis of cerebellum.

• Journal of IKEEE
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• v.15 no.3
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• pp.191-197
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• 2011

An image segmentation model using fuzzy c-means with intuition (FCM-I) model is proposed for the segmentation of magnetic resonance image in this paper. In FCM-I, a measurement called intuition level is adopted so that the intuition level helps to alleviate the effect of noises. A practical magnetic resonance image data set is used for image segmentation experiment and the performance is compared with those of some conventional algorithms. Results show that the segmentation method based on FCM-I compares favorably to several conventional clustering algorithms. Since FCM-I produces cluster prototypes less sensitive to noises and to the selection of involved parameters than the other algorithms, FCM-I is a good candidate for image segmentation problems.

• Journal of the Korean Magnetic Resonance Society
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• v.19 no.3
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• pp.106-111
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• 2015

Helicobacter pylori (H. pylori) survives in acidic and fluctuating pH conditions of the stomach. The pH effect on H. pylori proteins is important for the advanced understanding of its evolution and viability, although this bacterium has the molecular machinery that neutralizes the acidic condition. HP1492 is known as a conserved NifU-like protein from H. pylori. NifU is a nitrogen fixation protein that mediates the transfer of iron-sulfur (Fe-S) cluster to iron-sulfur proteins like ferredoxin. Commonly, the monomeric reduced state of NifU can be converted to the dimeric oxidized state by intermolecular disulfide bond formation. Because it remains unclear that HP1492 actually behaves as known NifU protein, we first found that this protein can adopt both oxidized and reduced forms using size exclusion chromatography. Circular dichroism experiment showed that HP1492 is relatively well-structured at pH 6.5, compared to other pH conditions. On the basis of the backbone resonance assignment of HP1492, we further characterized the residues that are sensitive to pH using NMR spectroscopy. These residues showing large chemical shift changes could be mapped onto the secondary structure of the protein. Our results could provide the foundation for structural and biophysical studies on a wide spectrum of NifU proteins.

• Progress in Medical Physics
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• v.15 no.1
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• pp.45-53
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• 2004

SPM has been widely applied for comparison studios of the functional image data among groups of patients or individuals under different conditions and these images are from people ranging from children to adults. However, the analysis of children's brain images by using SPM can make children's brain images normalized to an adult's template image and this can result in some errors. So this study created the children's mean MR images based on the Magnetic Resonance Images of 36 normal children (age: 2～6, average age: 4.36, SD age: 1.41, M/F: 17/19), and the children's mean SPECT images by using SPECT images of 13 normal children (age: 2～6, average age: 4.80, SD age: 1.17, M/F: 10/3). We created the Korean children's brain template image, based on those mean images, and then we compared between the positions of the clusters, based on the blood flow, by normalizing ADHD children's SPECT image to Korean children's template image and SPM adult's template image. As a result of the analysis, the variation of the cluster positions was found to be a maximum of 25 ㎜. Therefore, we should be aware that we need to consider the template image and the p-value when we analyze the chlidren's brain image by using SPM.