• 대한수학회보
• /
• 제46권2호
• /
• pp.311-319
• /
• 2009

Let H be a Hilbert space which is the direct sum of five closed subspaces $X_0,\;X_1,\;X_2,\;X_3$ and $X_4$ with $X_1,\;X_2,\;X_3$ of finite dimension. Let J be a $C^{1,1}$ functional defined on H with J(0) = 0. We show the existence of at least four nontrivial critical points when the sublevels of J (the torus with three holes and sphere) link and the functional J satisfies sup-inf variational inequality on the linking subspaces, and the functional J satisfies $(P.S.)^*_c$ condition and $f|X_0{\otimes}X_4$ has no critical point with level c. For the proof of main theorem we use the nonsmooth version of the classical deformation lemma and the limit relative category theory.

• 천문학회보
• /
• 제35권1호
• /
• pp.60.2-60.2
• /
• 2010

We have studied the abundance ratio of HNC and HCN toward the Red MSX Sources (RMS) using HCN (J=1-0), HNC (J=1-0), $H^{13}CN$ (J=1-0), $HN^{13}C$ (J=1-0),and $N_2H^+$ (J=1-0) lines observed with the Mopra 22 m radio telescope. The RMS are massive young stellar objects identified by the MSX satellite data combined with the 2MASS data. HCN and HNC (a geometrical isomer of HCN) are among the most basic interstellar molecules. According to our analysis, the column density of HCN is found to be correlated with that of HNC. Additionally, the [HNC]/[HCN] abundance ratio is sensitive to the core temperature because HNC is depleted in high temperature regions. This result is consistent with the previous results seen in low mass starless or protostellar cores.

• 열처리공학회지
• /
• 제7권3호
• /
• pp.175-183
• /
• 1994

The effect of batch annealing conditions and austenitizing temperatures on the hardness and microstructural factors were examined by using 420J2 martensitic stainless steel. In spite of the similler hardness after batch annealing, the difference in hardness at the same austenitizing temperature was caused by changes in dissolved carbon during batch annealing. The highest hardness of the specimen was obtained at the batch annealing temperature of $820^{\circ}C$ and austenitizing temperature of $1050^{\circ}C$. The main factor affecting the final hardness of the cold annealed 420J2 specimen was proved to the austenitizing temperature rather than batch annealing temperature.

• Kyungpook Mathematical Journal
• /
• 제48권2호
• /
• pp.281-286
• /
• 2008

In this note we prove that if A and $B^*$ are subnormal operators and is a bounded linear operator such that AX - XB is a Hilbert-Schmidt operator, then f(A)X - Xf(B) is also a Hilbert-Schmidt operator and $${\parallel}f(A)X\;-\;Xf(B){\parallel}_2\;\leq\;L{\parallel}AX\;-\;XB{\parallel}_2$$, for f belonging to a certain class of functions. Furthermore, we investigate the similar problem in the case that S, T are hyponormal operators and $X\;{\in}\;\cal{L}(\cal{H})$ is such that SX - XT belongs to a norm ideal (J, ${\parallel}\;{\cdot}\;{\parallel}_J$) and prove that f(S)X - Xf(T) $\in$ J and ${\parallel}f(S)X\;-\;Xf(T){\parallel}_J\;\leq\;C{\parallel}SX\;-\;XT{\parallel}_J$, for f in a certain class of functions.

• Journal of Korean Neurosurgical Society
• /
• 제30권5호
• /
• pp.553-560
• /
• 2001

Objective : The objective of this study was to determine the photodynamic therapeutic response of U-87 human glioma cell in vitro as well as in the nude rat xenograft model using photofrin as photosensitizer. Material and Method : U-87 cells were cultured on 96-well culture plates, photofrin(Quadralogic Technologies Inc., Vancouver, Canada) was added into the cell culture medium at concentration of $1{\mu}g/ml$, $2.5{\mu}g/ml$, $5{\mu}g/ml$, $10{\mu}g/ml$ and $20{\mu}g/ml$. 24 hour after drug treatment, cells were treated with optical(632nm) irradiation of $100mJ/cm^2$, $200mJ/cm^2$ and $400mJ/cm^2$. Photofrin(12.5mg/kg, i.p.) was administered to 28 nude rats containing intracerebral U-87 human glioma as well as 26 normal nude rats. 48 hours after administration, animals were treated with optical irradiation(632nm) of $35J/cm^2$, $140J/cm^2$ and $280J/cm^2$ to exposed tumor and normal brain. The photofrin concentration was measured in tumor and normal brain in a separate population of animals. Results : By MTT assay, there was 100% cytotoxicity at any dose of photofrin with optical irradiation of $200mJ/cm^2$ and $400mJ/cm^2$. But at the optical irradiation of $100mJ/cm^2$ cells were killed in dose dependent manner 28.5%, 49.1%, 54.4%, 78.2%, and 84.6% at concentration of $1{\mu}g/ml$, $2.5{\mu}g/ml$, $5{\mu}g/ml$, $10{\mu}g/ml$ and $20{\mu}g/ml$, respectively. Dose dependent PDT lesions in both tumor and normal brain were observed. In the tumor lesion, only superficial tissue damage was found with optical irradiation of $35J/cm^2$. However, in the optical irradiation group of $140J/cm^2$ and $280J/cm^2$ the volume of lesions was measured of $7.2mm^3$ and $14.0mm^3$ for treatment at $140J/cm^2$ and $280J/cm^2$, respectively. The U-87 bearing rats showed a photofrin concentration in tumor tissue of $6.53{\pm}2.16{\mu}g/g$, 23 times higher than that found in the contralateral hemisphere of $0.28{\pm}0.15{\mu}g/g$. Conclusion : Our data indicate that the U-87 human glioma in vitro and in the xenografted rats is responsive to PDT. At these doses, a reproducible injury can be delivered to human glioma in this model. Strategies to spare the normal brain collateral damage are being studied.

• 한국초전도학회:학술대회논문집
• /
• 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
• /
• pp.51-55
• /
• 2000

Using modified melt-textured grown targets, YBa$_2$Cu$_3$O$_{7-{\delta}}$ thin films were prepared by pulsed laser deposition technique at the laser energy density from 1 J/cm$_2$ to 4 J/cm$_2$. All the films showed c-axis preferred orientations, however, a-axis outgrowths on the film surface were considerably increased with an increase of the laser energy density. To examine the origin of the a-axis outgrowth formation, the microstructures of films deposited at 2 J/cm$_2$ and 4 J/cm$_2$ were investigated using X-ray diffraction, transmission electron microscopy, and high-resolution electron microscopy. It was shown that a significant number of Y$_2$O$_3$ inclusions were formed during the growth of c-axis oriented films at 4 J/cm$_2$. These inclusions formed nucleation sites for the a-axis outgrowths. It is considered that, due to the unstable growth conditions with a high flux density of incident vapor species and the strain induced by the surrounding c-axis films, the Y$_2$O$_3$ inclusions would prefer the nucleation of α-axis grains.

• 한국초전도ㆍ저온공학회논문지
• /
• 제4권1호
• /
• pp.4-7
• /
• 2002

Samples of $Nb/Al-AlO_x/Nb$ tunnel junction with the size of $50 ${\mu}{\textrm}{m}$ {\times} 50 ${\mu}{\textrm}{m}$$ were fabricated by using self-aligning and reactive ion etching technique In the high quality samples, the $V_m$ value (the product of the critical current and subgap resistance measured at 2 mV) was 34 mV at the critical current density of $J_c: 500 A/cm^2 and the V_g$ value (the gap voltage) was 2.8 mV. For the higher $J_c$ sample, voltage fluctuation at the gap voltage was observed. The $V_m and J_c$ values for this sample were 8 mV and 900 A/cm$^2$, respectively. Also, the relationship between critical current density $J_c$ and specific normal conductance $G_s$ of the junctions with $J_c$ in the range of 28 A/cm$^2$~940 A/cm$^2$was investigated.

• 대한화학회지
• /
• 제11권2호
• /
• pp.63-69
• /
• 1967

NaAc와 HAc로 된 緩衝溶液에서 납의 mono di, tri, Acetato Complexes의 安定度常數를 이온强度 2.00, 1.00, 0.75, 그리고 溫度 $150^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$, $35^{\circ}C$에서 Leden의 電位測定法으로 測定하고, $15^{\circ}C$에서는 Hume과 DeFord의 Polarographie Method로서도, 아울러 測定比較하였다. 安定度常數(Kijk)와 이온强度(${\mu}j$), 그리고 溫度(Tk) 사이에 다음과 같은 關係가 있음을 알았다. log Kijk = (Ai/${\mu}j^3$+ Bi) / Tk + Ci/${\mu}j^3$ + Di

• Advances in Traditional Medicine
• /
• 제8권1호
• /
• pp.86-92
• /
• 2008

The aim of the study was to evaluate in vitro antioxidant and cytotoxic activities of the methanolic extracts of leaves of Solanum sisymbrifolium, Solanum anguivi multiflora, Solanum barbisetum and Solanum jasminoides. In the in vitro antioxidant screening using ABTS [2,2'-azino-bis (3-ethylbenzo-thiazoline-6-sulphonic acid) diammonium salt] method, the methanol extracts of Solanum jasminoides, Solanum barbisetum and Solanum anguivi multiflora exhibited potent antioxidant activity with $IC_{50}$ values 31.25 $\pm$ 0.35, 40.33 $\pm$ 0.57 and 54.33 $\pm$ 0.57 ${\mu}g$/ml, respectively. Solanum barbisetum also showed potent activity in DPPH [1,1-diphenyl-2-picryl hydrazyl] method with an $IC_{50}$ value of 55.33 $\pm$ 1.66 ${\mu}g/ml. In the cytotoxicity studies, the methanol extract of Solanum barbisetum exhibited moderate activity against Vero, HEp-2, HeLa and A-549 cell lines with $IC_{50}$ values in the range of 83.30 - 127.30 ${\mu}g$/ml. Solanum anguivi multiflora extract also showed moderate activity against Hep-2 cell line with $IC_{50}$ value of 80.13 ${\mu}g$/ml. Solanum barbisetum possessing both the activities requires further investigation.

• Bulletin of the Korean Chemical Society
• /
• 제32권2호
• /
• pp.687-692
• /
• 2011

$^1H$ and $^{13}C$ NMR spectra of series of (E)-1-aryl-(2- and 3-thienyl)-2-propenones, that are aldol condensation products between 2- and 3-thiophenecarbaldehydes and m- and p-substituted acetophenones, were examined to make complete assignments of the chemical shifts. Long range couplings, $^4J$ and $^5J$, are observed in the $^1H-^1H$ COSY of both 2- and 3-thienyl compounds, which makes the elucidation of the conformation in solution possible. In contrast, the 2-furyl analogue shows the long range coupling phenomena, but the 3-furyl and phenyl analogues do not show similar phenomena.