• Journal of Veterinary Clinics
• /
• v.25 no.6
• /
• pp.514-517
• /
• 2008

A 9-year-old female mixed breed dog was presented due to cluster seizure episode. A mass in the frontal lobe was noted on brain magnetic resonance imaging (MRI). The dural tail sign was identified on contrast MR images. Based on MRI findings, intracranial meningioma was suspected strongly. The patient's symptom was controlled well by a combination therapy of hydroxyurea and prednisolone, and survived for fourteen months after diagnosis. This case report demonstrated that the clinical findings, imaging characteristics of a dog with suspected intracranial meningioma and long-term survival after hydroxyurea plus prednisolone therapy.

• Journal of the Korean Magnetic Resonance Society
• /
• v.27 no.4
• /
• pp.23-27
• /
• 2023

Hoxc, or the Homeobox C cluster, is a group of genes that play a crucial role in embryonic development, particularly in patterning the body along the anterior-posterior axis. These genes encode transcription factors, which are proteins that bind to DNA and regulate the expression of other genes. Hoxc9 is specifically involved in the development of the skeletal system, nervous system, and adipose tissue. Hoxc9 overexpression has been linked to the development of various cancers such as leukemia and breast cancer. Here, we assigned the chemical shifts Hoxc9 DNA binding domain (DBD) using heteronuclear NMR techniques. The helical regions of Hoxc9 DBD correspond to the residues T200 - F213 (Helix I), T218 - L229 (Helix II), and T232 - K249 (Helix III). Our result would be helpful for studing the molecular interactions of the Hoxc9 DBD and other proteins.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09b
• /
• pp.806-807
• /
• 2006

• Journal of Astronomy and Space Sciences
• /
• v.25 no.4
• /
• pp.375-382
• /
• 2008

On August 31, 2001, ${\sim}$ 1705 - 1718 UT, Cluster was located near the midnight magnetotail, GSE (x, y, z) ${\sim}$ (-19, - 2,2) RE, and observed fast earthward flow bursts in the vicinity of the neutral sheet. They occurred while the tail magnetic field suddenly increased. Using simultaneous measurements in the solar wind, at geosynchronous orbit, and on the ground, it is confirmed that tail magnetic field enhancement is due to an increased solar wind pressure. In the neutral sheet region, strongly enhanced earthward flow bursts perpendicular to the local magnetic field $(V_{{\perp}x})$ were observed. Auroral brightenings localized in the pre-midnight sector (${\sim}$ 2200 - 2400 MLT) occurred during the interval of the $V_{{\perp}x}$ enhancements. The $V_{{\perp}x}$ bursts started ${\sim}$ 2 minutes before the onset of auroral brightenings. Our observations suggest that the earthward flow bursts are associated with tail reconnection directly driven by a solar wind pressure impulse and that $V_{{\perp}x}$ caused localized auroral brightenings.

• Proceedings of the KIEE Conference
• /
• 2002.07c
• /
• pp.1515-1517
• /
• 2002

$MnO_2$ is used for the oxide electrode of electrochemical equipments because of its good electric conductivity and low oxygen overpotential. The effect of additives on the properties of $MnO_2$ has been investigated to enhance the electric conductivity and the stability in an acid solution. In this research, the effect of Ni addition on ${\beta}-MnO_2$ was studied by the theoretical quantum chemical method. The calculation was carried out by the discrete variation $X{\alpha}$ method, which is a sort of the first principle method and use Hatre-Fock-Slater approximation. The electron energy level, the density of state, the bond overlap population, the charge density distribution and the net ionic transfer between cations and anions were calculated and discussed. The used cluster model was $(Mn_{10}NiO_{44})^{-44}$.

• Journal of The Korean Astronomical Society
• /
• v.51 no.6
• /
• pp.185-195
• /
• 2018

Galaxy clusters are known to host many active galaxies (AGNs) with radio jets, which could expand to form radio bubbles with relativistic electrons in the intracluster medium (ICM). It has been suggested that fossil relativistic electrons contained in remnant bubbles from extinct radio galaxies can be re-accelerated to radio-emitting energies by merger-driven shocks via diffusive shock acceleration (DSA), leading to the birth of radio relics detected in clusters. In this study we assume that such bubble consist primarily of thermal gas entrained from the surrounding medium and dynamically-insignificant amounts of relativistic electrons. We also consider several realistic models for magnetic fields in the cluster outskirts, including the ICM field that scales with the gas density as $B_{ICM}{\infty}n^{0.5}_{ICM}$. Then we perform time-dependent DSA simulations of a spherical shock that runs into a lower-density but higher-temperature bubble with the ratio $n_b/n_{ICM}{\approx}T_{ICM}/T_b{\approx}0.5$. We find that inside the bubble the shock speed increases by about 20 %, but the Mach number decreases by about 15% in the case under consideration. In this re-acceleration model, the observed properties of a radio relic such as radio flux, spectral index, and integrated spectrum would be governed mainly by the presence of seed relativistic electrons and the magnetic field profile as well as shock dynamics. Thus it is crucial to understand how fossil electrons are deposited by AGNs in the ICM and how the downstream magnetic field evolves behind the shock in detailed modeling of radio relics.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1994.11a
• /
• pp.1-1
• /
• 1994

;The electronic state calculations for various types of ceramic materials have beell performed by the use of $DV-X\;{\alpha}$ cluster method. The molecular orbital levels and wave functions for model clusters have been computed to study the electronic properties ami chemical bonding of the ceramics. For ${\beta}-sialon(Si_{6-z}Al_zO_zN_{8-z})$ which is a high temperature structural material based on ${\beta}-Si_3N_4$, we have made model cluster calculations to estimate the strength of chemical bonding between atoms by the Mulliken population analysis. It is found that the covalent bonding between Si and N atoms is very strong in pure ${\beta}-Si_3N_4$, but the covalency around solute atom is considerably weakened when Si atom is substituted by AI. This tendency is enhanced by an additional substitution of oxygen atom for N. The result calculated can well explain the experimental data of changes in mechanical properties such as the reductions of Young's modulus and Vickers hardness with increment of z-value in ${\beta}-sialon$. Various model clusters for transition metal oxides which show many interesting physical and chemical properties have also been calculated. High-valent perovskite-type iron oxides EMFe0_3E(M=Ca and Sr) possess very interesting magnetic and chemical properties. In these oxides, iron exists as $Fe^{4+}$ state, but the experimental measurement of Mossba~er effect suggests that disproportionation $2Fe^{4+}=Fe^{3+}+Fe^{5+}$ takes place for $CaFe0_3$ at low temperatures. The model cluster calculations for these compounds indicated the existence of considerably strong covalent bonding of Fe-O. The calculations of hyperfine interaction at iron neucleus show very good agreement with the experimental Mossbauer measurements. The result calculated also implies that the disproportionation reaction is strongly possible by assuming the quenching of breathing phonon mode at low temperatures.tures.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.161-161
• /
• 2012

질화티타늄(Titanium Nitride, TiN)은 화학적 안정성이 우수하고, N/Ti 원소 비율에 따라 열전도성 및 전기전도성이 변화하는 특성을 가지고 있어서 Metal Insulator Silicon (MIS) 나 Metal Insulator Metal (MIM) capacitor의 metal electrode 물질로 적용되고 있다. $TiCl_4$와 $NH_3$ gas를 이용하여 $500^{\circ}C$ 이상의 고온 조건에서 Chemical Vapor Deposition (CVD) 법으로 TiN 박막을 증착하는 방식이 가장 널리 사용되고 있으나, TiN 박막 내의 Chlorine (Cl) 원소가 SiO2 두께와 누설전류 밀도를 증가시키는 요인으로 작용하므로 Cl의 거동 및 함량 제어를 통한 전기적인 특성의 향상 평가가 요구되고 있다[1-3]. 본 실험에서는 $SiO_2$ 위에 TiN을 적층 한 구조에서 magnetic sector type의 Secondary Ion Mass Spectrometry (SIMS)를 이용하여 Cl 원소의 검출도 개선 방법을 연구하였다. 일반적인 $Cs^+$ 이온을 이용하여 $Cl^-$ 이온을 검출할 경우에는 TiN 하부에 $SiO_2$가 존재함에 따른 charging effect와 mass interference가 발생되는 문제점이 관찰되었다. 이를 개선하기 위해 Cl과 Cs 원소가 결합된 $ClCs^+$ cluster ion을 검출하는 방법을 시도하였으나, Cl- 이온 검출 방식에 비해 오히려 낮은 검출도를 나타내었으나 Cl 원소가 속하는 halogen 족 원소의 높은 전자 친화도 특성을 이용한 $ClCs_2^+$ cluster ion을 검출하는 방법[4]을 적용한 경우에는 $ClCs^+$ 방식에 비해 검출도가 3order 개선되는 결과를 확보하였으며, 이 결과를 토대로 Cl dose ($atoms/cm^2$) 와 Rs (ohm/sq) 간의 상관 관계에 대해 고찰하고자 한다.

• Journal of the Korean Magnetics Society
• /
• v.9 no.6
• /
• pp.285-290
• /
• 1999

The magnetic properties of sputtered amorphous $Fe_{86.7}Zr_{3.3}B_4Ag_6$ thin films, which contains an additional insoluble element Ag, have been investigated as a function of uniaxal field annealing temperature. The amorphous $Fe_{86.7}Zr_{3.3}B_4Ag_6$ thin films produced by relatively low temperature annealing at 40$0^{\circ}C$ for 1 hour was found to have very high permeability of 7800 at 50 MHz, 0.2 mOe, high magnetization of 1.7 T, low coercivity of 1.0 Oe and very low core loss of 1.4 W/cc at 1 MHz, 0.1 T, respectively. It is notable that the permeability and core loss values for various kinds of the soft magnetic thin films reported up to now. The reason for the appearance for the good soft magnetic properties is presumably due to the homogeneous formation of very fine bcc $\alpha$-Fe clusters with the size in the amorphous $Fe_{86.7}Zr_{3.3}B_4Ag_6$ thin films matrix, which can be deduced from the XRD results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.148-151
• /
• 2003

The spin density of ${\beta}-MnO_2$ structure was theoretically investigated by $DV-X_{\alpha}$ (the discrete variation $X{\alpha}$) method, which is a sort of the first principle molecular orbital method using Hatre-Fock-Slater approximation. The used cluster model was $[Mn_{14}O_{56}]^{-52}$. The ${\beta}-MnO_2$ is a paramagnetic oxide semiconductor material having the energy band gap of 0.18 eV and an 3 loan-pair electrons in the 3d orbital of an cation. This material exhibits spin-only magnetism and has the magnetic ordering temperature of 94 K. Below this temperature its magnetism appears as antiferromagnetism. The calculations of electronic state showed that if the initial spin condition of input parameters changed, the magnetic state changed from paramagnetic to antiferromagnetic. When d orbital of all Mn atoms in cluster had same initial spin state as only up spin, paramagnetic spin density distribution appeared by the calculation. On the other way, d orbital had alternately changed spin state along special direction the resulted spin distribution showed antiferromagnetism.