• 대한수학회보
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• 제46권1호
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• pp.35-43
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• 2009

We say that an isometric immersed hypersurface x : $M^n\;{\rightarrow}\;{\mathbb{R}}^{n+1}$ is of $L_k$-finite type ($L_k$-f.t.) if $x\;=\;{\sum}^p_{i=0}x_i$ for some positive integer p < $\infty$, $x_i$ : $M{\rightarrow}{\mathbb{R}}^{n+1}$ is smooth and $L_kx_i={\lambda}_ix_i$, ${\lambda}_i\;{\in}\;{\mathbb{R}}$, $0{\leq}i{\leq}p$, $L_kf=trP_k\;{\circ}\;{\nabla}^2f$ for $f\;{\in}\'C^{\infty}(M)$, where $P_k$ is the kth Newton transformation, ${\nabla}^2f$ is the Hessian of f, $L_kx\;=\;(L_kx^1,\;{\ldots},\;L_kx^{n+1})$, $x=(x^1,\;{\ldots},\;x^{n+1})$. In this article we study the following(hyper)surfaces in ${\mathbb{R}}^{n+1}$ from the view point of $L_1$-finiteness type: totally umbilic ones, generalized cylinders $S^m(r){\times}{\mathbb{R}}^{n-m}$, ruled surfaces in ${\mathbb{R}}^{n+1}$ and some revolution surfaces in ${\mathbb{R}}^3$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.410-411
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• 2007

To investigate the ZnO LED which are interested in the next generation of short wavelength LEDs and Lasers, the ZnO thin films were deposited by RF magnetron sputtering system. The p-type ZnO thin film, fabricated by means of the ampoule-tube method, was used to make the ZnO p-n junction, and its characteristics was analyzed. The ampoule-tube method was used to make the p-type ZnO based on the As diffusion, and the hall measurement was used to confirm that the p-type is formed. the current-voltage characteristics of the ZnO p-n junction were measured to confirm the rectification characteristics of a typical p-n junction and the low leakage voltage characteristics. Analysis of ZnO LED V-I curve will provide a very useful technology for producing the UV ZnO LED and ZnO-based devices.

• 천문학회지
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• 제47권1호
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• pp.1-13
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• 2014

We analyze the dependence of disk morphology (arm class, Hubble type, bar type) of nearby spiral galaxies on the galaxy environment by using local background density (${\Sigma}_n$), projected distance ($r_p$), and tidal index (T I) as measures of the environment. There is a strong dependence of arm class and Hubble type on the galaxy environment, while the bar type exhibits a weak dependence with a high frequency of SB galaxies in high density regions. Grand design fractions and early-type fractions increase with increasing ${\Sigma}_n$, $1/r_p$, and T I, while fractions of flocculent spirals and late-type spirals decrease. Multiple-arm and intermediate-type spirals exhibit nearly constant fractions with weak trends similar to grand design and early-type spirals. While bar types show only a marginal dependence on ${\Sigma}_n$, they show a fairly clear dependence on $r_p$ with a high frequency of SB galaxies at small $r_p$. The arm class also exhibits a stronger correlation with $r_p$ than ${\Sigma}_n$ and T I, whereas the Hubble type exhibits similar correlations with ${\Sigma}_n$ and $r_p$. This suggests that the arm class is mostly affected by the nearest neighbor while the Hubble type is affected by the local densities contributed by neighboring galaxies as well as the nearest neighbor.

• Journal of Oral Medicine and Pain
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• 제36권1호
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• pp.25-37
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• 2011

측두하악장애증상 및 기여요인과 성격유형과의 관련성을 규명하고자 경기도 지역 대학에 재학중인 학생 199명(평균연령 $21.0{\pm}2.9$세, 남자 73명, 여자 126명)을 대상으로 MBTI 검사와 설문조사를 실시하여 다음과 같은 결과를 얻었다. 1. 내향성(I)이 외향성(E)보다, 감각형(S)이 직관형(N)보다, 사고형(T)이 감정형(F)보다, 인식형(P)이 판단형(J)보다 한 가지 이상의 주관적 측두하악장애증상을 가지고 있는 자의 비율 및 한가지 이상의 기여요인을 갖는 자의 기여요인 수 평균치가 높은 경향을 보였다. 2. ISTP와 ISFP는 다른 성격유형들에 비해 한 가지 이상의 주관적 측두하악장애증상을 가지고 있는 사람의 비율과 한 가지 이상의 기여요인을 갖는 사람의 비율에서 높은 경향을 보였다. 3. 내향성(I)이 외향성(E)보다, 감각형(S)이 직관형(N)보다, 감정형(F)이 사고형(T)보다, 판단형(J)이 인식형(P)보다 개구시 악관절부 동통 증상의 빈도가 높은 경향을 보였다. 4. 이악물기 습관과 스트레스는 내향성(I)이 외향성(E)보다 높은 빈도를 보였고(p<0.05), 껌 씹는 습관은 외향성(E)이 내향성 (I)보다 높은 빈도를 보였다(p<0.05). 5. 편측저작습관은 판단형(J)이 인식형(P)보다 높은 빈도를 보였다(p<0.05). 6. 성격이 느긋한 편이거나 보통인 경우보다는 예민한 편이거나 신경질적인 경우가 측두하악장애 증상수의 평균치가 높게 나타났다(p<0.001). 7. 보통 성격이 다른 성격들에 비해 기여요인 수의 평균치가 가장 낮게 나타났다(p<0.0001). 결론적으로 측두하악장애는 개인의 성격과 관계가 있으므로 환자의 성격 유형을 고려한 상담과 교육의 활용이 측두하악 장애 치료에 도움이 되리라 사료된다.

• 대한수학회보
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• 제34권4호
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• pp.549-560
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• 1997

For positive integers $n_i \geq 2, i = 1, 2, 3, 4$, such that $\Sigma \frac{n_i}{1} < 2$, there exists a quadrilateral $P = P_1 P_2 P_3 P_4$ in the hyperbolic plane $H^2$ with the interior angle $\frac{n_i}{\pi}$ at $P_i$. Let $\Gamma \subset Isom(H^2)$ be the (discrete) group generated by reflections in each side of $P$. Then the quotient space $H^2/\gamma$ is a differentiable orbifold of type $(^* n_1 n_2 n_3 n_4)$. It will be shown that the deformation space of $Rp^2$-structures on this orbifold can be mapped continuously and bijectively onto the cell of dimension 4 - \left$\mid$ {i$\mid$n_i = 2} \right$\mid$$.

• 한국진공학회지
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• 제12권4호
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• pp.257-262
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• 2003

n-type과 p-type 다공성 실리콘 (PS)의 구조에 따른 광학적 및 전기적 특성을 조사하였다. 먼저 화학적 에칭에 의하여 다공성 실리콘 시편을 준비했다. 이 시편의 미세구조의 특징을 주로 SEM, AFM, XRD 분석에 의하여 관찰하였으며 그들의 광학적 화학적 특성을 PL과 FTIR을 통해 측정하였다. n-type다공성 실리콘의 상온 PL파장은 p-type 다공성 실리콘이 남색 영역 (400-650 nm)임에 반해 500-650 nm로 이동함을 알 수 있었다. 또한 PS층 위에 ∼40 nm 두께의 반투명한 Cu박막을 rf 스퍼터링법으로 증착하여 PS내의 pore를 Cu로 충전한 시편의 I-V 특성과 EL 특성을 관찰했다.

• 대한수학회지
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• 제36권6호
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• pp.1133-1143
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• 1999

Chaterji strengthened version of a theorem for martin-gales which is a generalization of a theorem of Marcinkiewicz proving that if $X_n$ is a sequence of independent, identically distributed random variables with $E{\mid}X_n{\mid}^p\;<\;{\infty}$, 0 < P < 2 and $EX_1\;=\;1{\leq}\;p\;<\;2$ then $n^{-1/p}{\sum^n}_{i=1}X_i\;\rightarrow\;0$ a,s, and in $L^p$. In this paper, we probe a version of law of large numbers for double arrays. If ${X_{ij}}$ is a double sequence of random variables with $E{\mid}X_{11}\mid^log^+\mid X_{11}\mid^p\;<\infty$, 0 < P <2, then $lim_{m{\vee}n{\rightarrow}\infty}\frac{{\sum^m}_{i=1}{\sum^n}_{j=1}(X_{ij-a_{ij}}}{(mn)^\frac{1}{p}}\;=0$ a.s. and in $L^p$, where $a_{ij}$ = 0 if 0 < p < 1, and $a_{ij}\;=\;E[X_{ij}\midF_[ij}]$ if $1{\leq}p{\leq}2$, which is a generalization of Etemadi's marcinkiewicz-type SLLN for double arrays. this also generalize earlier results of Smythe, and Gut for double arrays of i.i.d. r.v's.

• 대한수학회지
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• 제47권6호
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• pp.1147-1165
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• 2010

In this paper we compare a torsion free sheaf F on $P^N$ and the free vector bundle $\oplus^n_{i=1}O_{P^N}(b_i)$ having same rank and splitting type. We show that the first one has always "less" global sections, while it has a higher second Chern class. In both cases bounds for the difference are found in terms of the maximal free subsheaves of F. As a consequence we obtain a direct, easy and more general proof of the "Horrocks' splitting criterion", also holding for torsion free sheaves, and lower bounds for the Chern classes $c_i$(F(t)) of twists of F, only depending on some numerical invariants of F. Especially, we prove for rank n torsion free sheaves on $P^N$, whose splitting type has no gap (i.e., $b_i{\geq}b_{i+1}{\geq}b_i-1$ 1 for every i = 1,$\ldots$,n-1), the following formula for the discriminant: $$\Delta(F):=2_{nc_2}-(n-1)c^2_1\geq-\frac{1}{12}n^2(n^2-1)$$. Finally in the case of rank n reflexive sheaves we obtain polynomial upper bounds for the absolute value of the higher Chern classes $c_3$(F(t)),$\ldots$,$c_n$(F(t)) for the dimension of the cohomology modules $H^iF(t)$ and for the Castelnuovo-Mumford regularity of F; these polynomial bounds only depend only on $c_1(F)$, $c_2(F)$, the splitting type of F and t.

• 전자공학회논문지A
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• 제31A권5호
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• pp.126-133
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• 1994

Doping effects and semiconductor behaviors of the dispersed p- and n-Si, p- and n- GaAs particles in the aqueous electrolyte have been studied using microelectrophoretic, voltammetric and chronoamperometric techniques. The cations (K$^{+}$) are adsorbed on both the p- and n- Si particle surfaces regardless of the sign of space charges in the depletion layers, i.e. doping profiles. The surface states are negatively charged acceptor states. On the other hand, the anions (CI$^{-}$) are adsorbed on both the p- and n- GaAs particle surfaces regardless of the sign of space charges in the depletion layers, i.e. doping profiles. The surface states are positively charged donor states. Under the same conditions, electrophoretic mobilities, electrochemical processes, doping effects and related semiconductor behaviors of the Si and the GaAs particles are similar regardless of the doping profiles, i. e. dopants and doping concentrations. The doping effects and related semiconductor behaviors of the dispersed p- and n- type semiconductor particles are gradually lost with decreasing dimensions.

• 대한수학회보
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• 제32권2호
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• pp.329-336
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• 1995

Let $A_1, A_2, \ldots, A_n$ be a sequence of events on a given probability space and let $m_n$ be the number of those A's which occur. Put $S_{0,n} = 1$ and $$ S_{k,n} = \Sigma P(A_i_1 \cap A_i_2 \cap \cdots \cap A_i_k), (a \leq k)$$ where the summation is over all subscripts satisfying $1 \let i_1 < i_2 < \cdots < i_k \leq n$.