• 충청수학회지
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• 제31권4호
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• pp.369-379
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• 2018

Let ${\mathbb{H}}_3$ be the 3-dimensional Heisenberg group equipped with a left-invariant metric. In this paper we calculate the volumes of geodesic balls in ${\mathbb{H}}_3$. Let $B_e(R)$ be the geodesic ball with center e (the identity of ${\mathbb{H}}_3$) and radius R in ${\mathbb{H}}_3$. Then, the volume of $B_e(R)$ is given by $$Vol(B_e(R))={\frac{\pi}{6}}\{-16R+(R^2+6){\sin}\;R+(R^3+10R){\cos}\;R+(R^4+12R^2){\int\nolimits_0^R}\;{\frac{{\sin}\;t}{t}}dt\}$$.

• Journal of Ecology and Environment
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• 제29권5호
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• pp.485-488
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• 2006

Allometric equations for biomass measurement of the shrub species, Lindera obtusiloba, were developed. The allometric equations between $(BD)^2H$ and dry weight of leaves ($W_I$), stems and branches ($W_{sb}$), roots ($W_r$) and total weight ($W_t$) of the Lindera obtusiloba were as follows: $W_I=0.7318\;(BD^2H)^{0.6108},\;W_{sb}=0.6067(BD^2H)^{0.8355},\;W_r=0.4524(BD^2H)^{0.7608},\;W_t=1.672 (BD^2H)^{0.7664}$. The $R^2s$ between $(BD)^2H\;and\;W_I,\;W_{sb},\;W_r\;and\;W_t$ of the Lindera obtusiloba were 0.9251, 0.9571, 0.9353 and 0.9546, respectively. Root weight of this Lindera obtusiloba was about 38% of the aboveground biomass.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.197-200
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• 2001

In this letter, we report on the investigation of Ni/Si/Ni Ohmic contacts to n-type 4H-SiC. Ohmic contacts have been formed by a vacuum annealing and $N_2$ gas ambient annealing method at $950^{\circ}C$ for 10 min. The specific contact resistivity ( $\rho_{c}$ ), sheet resistance($R_s$), contact resistance($R_c$), transfer length($L_T$) were calculated from resistance($R_T$) versus contact spacing(d) measurements obtained from 10 TLM(transmission line method) structures. The resulting average values of vacuum annealing sample were $\rho_{c}=3.8{\times}10^{-5}\Omega cm^{3}$, $R_{c}=4.9{\Omega}$, $R_{T}=9.8{\Omega}$ and $L_{T}=15.5{\mu}m$, resulting average values of another sample were $\rho_{c}=2.29{\times}10^{-4}\Omega cm^{3}$, $R_{c}=12.9{\Omega}$ and $R_{T}=25.8{\Omega}$. The physical properties of contacts were examined using X-Ray Diffraction and Auger analysis, there was a uniform intermixing of the Si and Ni, migration of Ni into the SiC.

• 대한수학회보
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• 제54권4호
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• pp.1331-1336
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• 2017

Assume that R is a commutative Noetherian ring with non-zero identity, a is an ideal of R, X is an R-module, and t is a non-negative integer. In this paper, we present upper bounds for the injective dimension of X in terms of the injective dimensions of its local cohomology modules and an upper bound for the injective dimension of $H^t_{\alpha}(X)$ in terms of the injective dimensions of the modules $H^i_{\alpha}(X)$, $i{\neq}t$, and that of X. As a consequence, we observe that R is Gorenstein whenever $H^t_{\alpha}(R)$ is of finite injective dimension for all i.

• 대한수학회논문집
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• 제31권4호
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• pp.695-701
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• 2016

Let I and J be two ideals of a commutative Noetherian ring R and M, N be two non-zero finitely generated R-modules. Let t be a non-negative integer such that $H^i_{I,J}(N)$ is (I, J)-minimax for all i < t. It is shown that the generalized local cohomology module $H^i_{I,J}(M,N)$ is (I, J)-Cofinite minimax for all i < t. Also, we prove that the R-module $Ext^j_R(R/I,H^i_{I,J}(N))$ is finitely generated for all $i{\leq}t$ and j = 0, 1.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 1999년도 제2회 총회 및 춘계학술발표회
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• pp.35-35
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• 1999

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2008년도 추계학술대회 초록집
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• pp.11-12
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• 2008

Micron-sized Co-alloy T800 powder was coated on Inconel718 (IN718) using high velocity oxygen fuel (HVOF) thermal spraying by the optimal coating process (OCP) determined from the best surface hardness of 16 coatings prepared by Taguchi program. The surface hardness improved 140-160 % from 399 Hv of IN718 to 560-630 Hv by the coating. Porosity of the coating was 1.0-2.7 %, strongly depending on spray parameters. Both friction coefficients (FC) and wear traces (WT) of the coating were smaller than those of IN718 substrate at both $25^{\circ}C$ and $538^{\circ}C$. FC and WT of IN718 and coating decreased with increasing the surface temperature. Tensile bond strength (TBS) and fracture location (FL) of Ti64/T800 were 8,770 psi and near middle of T800 coating respectively. TBS and FL of Ti64/NiCr/T800 were 8,740 psi and near middle of T800 coating respectively. This showed that cohesion of T800 coating was 8,740-8,770 psi, and adhesion of T800 on Ti64 and NiCr was stronger than the cohesion of T800.

• Journal of Plant Biology
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• 제29권1호
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• pp.53-65
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• 1986

The montane forests of Ulreung Island, Korea, were investigated by the ZM school method. By comparing the montane forests of this island with those of Korean Peninsula and of Japan, a new order, F a g e t a l i a m u l t i n e r v i s, a new alliance, F a l g i o n m u l t i n e r v i s, a new association, H e p a t i c o-F a g e t u m m u l t i n e r v i s and Rhododendron brachycarpum-Pinus parviflora community were recognized. The H e p a t i c o - F a g e t u m m u l t i n e r v i s was further subdivided into four subassociations; Subass. of Sasa kurilensis, Subass. of Rumohra standishii, Subass. of Rhododendron brachycarpum and Subass. of typicum. Each community was described in terms of floristic, structural and environmental features.

• 한국양식학회지
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• 제3권1호
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• pp.79-88
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• 1990

우렁쉥이의 효율적인 종묘생산을 위한 생물학적 기초자료를 얻고자 산란유발, 난발생 및 채묘에 미치는 환경요인으로서 수온과 조도의 영향에 대하여 실험한 결과는 다음과 같다. 1. 자극수온별 생산유발 결과 $14^{\circ}C$에서 가장 많은 산란량을 보였고, $12^{\circ}C$에서 가장 높은 수정률을 나타냈다. 2. 난발생의 각단계에 이르기까지의 수온(T, $^{\circ}C$)에 따른 발생속도(h, 시간)는 수온이 높을 수록 빨랐으며, 그 관계식은 다음과 같다. 8세포 1/h =0.0147 T-0.0069(.=0.9816) 32세포 1/h =0.0100 T-0.0017(r=0.9672) 초기미충형유생 1/h =0.0043 T+0.0024(r=0.9913) 부화유생 1/h =0.0021 T-0.0021 (r=0.9898) 3. 우렁쉥이의 수온과 난발생속도와의 관계에서 추정된 난발생의 생물학적영도는 평균 $0.27^{\circ}C$ 였다. 4. 우렁쉥이의 난발생이 가능한 하한수온 및 상한수온은 각각 $0^{\circ}C$, $24^{\circ}C$였다. 5. 수온별유생의 부착률은 $14^{\circ}C$에서 가장 높았으며, $14^{\circ}C$를 정점으로 수온이 상승, 하강 할 수록 저조한 부착률을 나타냈다.

• 대한수학회보
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• 제48권5호
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• pp.917-922
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• 2011

Let R be a prime ring, H a generalized derivation of R, L a noncentral Lie ideal of R, and 0 ${\neq}$ a ${\in}$ R. Suppose that $au^sH(u)u^t$ = 0 for all u ${\in}$ L, where s; t ${\geq}$ 0 are fixed integers. Then H = 0 unless satisfies $S_4$, the standard identity in four variables.