• 대한수학회보
• /
• 제57권3호
• /
• pp.583-595
• /
• 2020

Let HE_I, HE_II, HE_III and HE_IV be the first, second, third and fourth type Loo-Keng Hua domain respectively, 𝜑 a holomorphic self-map of HE_I, HE_II, HE_III, or HE_IV and u ∈ H(𝓜) the space of all holomorphic functions on 𝓜 ∈ {HE_I, HE_II, HE_III, HE_IV}. In this paper, motivated by the well known Hua's matrix inequality, first some inequalities for the points in the Bers-type spaces of the Loo-Keng Hua domains are obtained, and then the boundedness and compactness of the weighted composition operators W_𝜑,u : f ↦ u · f ◦ 𝜑 on Bers-type spaces of these domains are characterized.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
• /
• pp.53-56
• /
• 2004

Recently the interferometric synthetic aperture radiometer with sub-Y-type antenna array was suggested to improve the spatial resolution than that of conventional Y-type with the same number of antenna elements. The sub-Y-type performance has been reported under a point source target. In this paper, the performance of sub-Y-type is evaluated under contiguous objects. The angular resolution of sub-Y-type with 52 antennas was compared with that of Y-type with the 40 antennas. The images of sub-Y -type and Y-type array were simulated under the contiguous objects. The sub-Y-type showed higher resolution than Y-type in the simulation and experiments. The sub-Y-type has high spatial resolution than Y-type in case of contiguous source as well as single point source.

• 대한수학회보
• /
• 제61권2호
• /
• pp.401-419
• /
• 2024

Let K, H, K_II and H_II be the Gaussian curvature, the mean curvature, the second Gaussian curvature and the second mean curvature of a timelike tubular surface T_γ(α) with the radius γ along a timelike curve α(s) in Minkowski 3-space E³₁. We prove that T_γ(α) must be a (K, H)-Weingarten surface and a (K, H)-linear Weingarten surface. We also show that T_γ(α) is (X, Y)-Weingarten type if and only if its central curve is a circle or a helix, where (X, Y) ∈ {(K, K_II), (K, H_II), (H, K_II), (H, H_II), (K_II , H_II)}. Furthermore, we prove that there exist no timelike tubular surfaces of (X, Y)-linear Weingarten type, (X, Y, Z)-linear Weingarten type and (K, H, K_II, H_II)-linear Weingarten type along a timelike curve in E³₁, where (X, Y, Z) ∈ {(K, H, K_II), (K, H, H_II), (K, K_II, H_II), (H, K_II, H_II)}.

• 한국결정성장학회지
• /
• 제31권5호
• /
• pp.197-202
• /
• 2021

Z형 육방정 페라이트인 Ba₃Co₂Fe₂₄O₄₁(Ba₃Z)와 Ba_1.5La_1.5Co₂Fe₂₄O₄₁(Ba_1.5La_1.5Z) 분말을 1차 하소 후 용융염 합성법을 통해 합성하였다. Ba₃Z의 경우, 1000℃에서 하소한 결과 M형 육방정 페라이트와 Y형 육방정 페라이트가 합성되었으며, 이후 1150℃와 1200℃에서 소결했을 때 Z형 육방정 페라이트를 얻을 수 있었다. 하지만 Ba_1.5La_1.5Z의 경우 1000℃에서 하소하였을 때 M형 육방정 페라이트와 CoFe₂O₄(Spinel 상) 그리고 LaFeO₃으로 합성되었으며, Z형 육방정 페라이트는 용융염 합성 과정에서 합성되지 않았다. 또한 입자 형상의 종횡비는 용융염 합성 시 소결온도가 증가함에 따라 감소하는 경향을 보였다. 따라서 높은 종횡비를 갖는 단상의 Ba_1.5La_1.5Z를 합성하기 위해서는 용융염 합성 전 1차 하소 온도가 Spinel 상이 형성되는 온도보다 낮아야 될 것으로 판단된다.

• Journal of Microbiology and Biotechnology
• /
• 제25권4호
• /
• pp.423-430
• /
• 2015

Aerobic CH₄ oxidation is an important CH₄ sink in landfills. To investigate the distribution and community diversity of methanotrophs and link with soil characteristics and operational parameters (e.g., concentrations of O₂, CH₄), cover soil samples were collected at different locations and depths from the Mengzi semi-aerobic landfill (SAL) in Yunnan Province of southern China. Specific PCR followed by denaturing gradient gel electrophoresis and realtime PCR were used to examine methanotrophs in the landfill cover soils. The results showed that different locations did harbor distinct methanotroph communities. Methanotrophs were more abundant in areas near the venting pipes because of the higher O₂ concentrations. The depth of 20-25 cm, where the ratio of the CH₄ to O₂ was within the range from 1.3 to 8.6, was more conducive to the growth of CH₄-oxidizing bacteria. Type II methanotrophs dominated in all samples compared with Type I methanotrophs, as evidenced by the high ratio of Type II to Type I methanotrophic copy numbers (from 1.76 to 11.60). The total copy numbers of methanotrophs detected were similar to other ecosystems, although the CH₄ concentration was much higher in SAL cover soil. Methylobacter and Methylocystis were the most abundant Type I and Type II methanotrophs genera, respectively, in the Mengzi SAL. The results suggested that SALs could provide a special environment with both high concentrations of CH₄ and O₂ for methanotrophs, especially around the vertical venting pipes.

• Bulletin of the Korean Chemical Society
• /
• 제30권8호
• /
• pp.1899-1902
• /
• 2009

• 한국재료학회지
• /
• 제30권5호
• /
• pp.262-266
• /
• 2020

In this paper, we investigated the effect of the passivation stack with Al₂O₃, hydrogenated silicon nitride (SiN_x:H) stack and Al₂O₃, silicon oxynitride (SiON_x) stack in the n type bifacial solar cell on monocrystalline silicon. SiNx:H and SiON_x films were deposited by plasma enhanced chemical vapor deposition on the Al₂O₃ thin film deposited by thermal atomic layer deposition. We focus on passivation properties of the two stack structure after laser ablation process in order to improve bifaciality of the cell. Our results showed SiN_x:H with Al₂O₃ stack is 10 mV higher in implied open circuit voltage and 60 ㎲ higher in minority carrier lifetime than SiON_x with Al₂O₃ stack at Ni silicide formation temperature for 1.8% open area ratio. This can be explained by hydrogen passivation at the Al₂O₃/Si interface and Al₂O₃ layer of laser damaged area during annealing.

• 호남수학학술지
• /
• 제28권2호
• /
• pp.221-224
• /
• 2006

A Kummer-type transformation formula for the generalized hypergeometric function $_2F_2$ deduced by Exton, rederived in two simple and transparent ways by Miller and generalized by Paris, is again derived by another method.

• 대한수학회보
• /
• 제57권2호
• /
• pp.429-441
• /
• 2020

Let M(X, Y) denote the space of multipliers from X to Y, where X and Y are analytic function spaces. As we known, for Dirichlet-type spaces 𝓓_α^p, M(𝓓_p-1^p, 𝓓_q-1^q) = {0}, if p ≠ q, 0 < p, q < ∞. If 0 < p, q < ∞, p ≠ q, 0 < s < 1 such that p + s, q + s > 1, then M(𝓓_p-2+s^p, 𝓓_q-2+s^q) = {0}. However, X ∩ 𝓓_p-1^p ⊆ X ∩ 𝓓_q-1^q and X ∩ 𝓓_p-2+s^p ⊆ X ∩ 𝓓_q-2+s^p whenever X is a subspace of the Bloch space 𝓑 and 0 < p ≤ q < ∞. This says that the set of multipliers M(X ∩ 𝓓 _p-2+s^p, X∩𝓓_q-2+s^q) is nontrivial. In this paper, we study the multipliers M(X ∩ 𝓓_p-2+s^p, X ∩ 𝓓_q-2+s^q) for distinct classical subspaces X of the Bloch space 𝓑, where X = 𝓑, BMOA or 𝓗^∞.

• 대한수학회논문집
• /
• 제18권4호
• /
• pp.603-613
• /
• 2003

When X is a threefold of general type, it is well known h/sup 0/(X, O/sub X/(nK/sub X/)) ≥ 1 for a sufficiently large n. When X(O/sub X/) 〉 0, it is not easy to obtain such an integer n. A. R. Fletcher showed that h/sup 0/(X, O/sub X/(nK/sub X/)) ≥ 1 for n = 12 when X(O/sub X/)=1. We introduce a technique different from A. R. Fletcher's. Using this technique, we also prove the same result as he showed and have a new result.