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Fabrication and Characteristics of $n-CdS_{0.69}Se_{0.31}/p-Cu_{2-x}S_{0.69}Se_{0.31}$ Heterojunction Solar Cell ($n-CdS_{0.69}Se_{0.31}/p-Cu_{2-x}S_{0.69}Se_{0.31}$ Heterojunction 태양전지의 제작과 특성)

  • Baek, Seung-Nam;Hong, Kwang-Joon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.04b
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    • pp.51-55
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    • 2004
  • $CdS_{0.69}Se_{0.31}$ single crystal grown by sublimation method. Hall effect measurement were carried out by the Van der Pauw method. The measurement values under the temperature were found to be carrier density $n=1.95{\times}10^{23}m^{-3}$, Hall coeffcient $RH=3.21{\times}10^{-5}m^3/c$, conductivity ${\sigma}=362.41{\Omega}^{-1}m^{-1}$, and Hall mobility ${\mu}=1.16{\times}10^{-2}m^2/v.s.$ Heterojunction solar cells of $n-CdS_{0.69}Se_{0.31}/p-Cu_{2-x}S_{0.69}Se_{0.31}$ were fabricated by the substitution reaction. The open-circuit voltage, short-circuit currint density, fill factor and power conversion efficiency of $n-CdS_{0.69}Se_{0.31}/p-Cu_{2-x}S_{0.69}Se_{0.31}$ heterojunction solar cell under $80mW/cm^2$ illumination were found to be 0.41V, $19.5mA/cm^2$, 0.75 and 9.99%, respectivity.

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ON THE MEAN VALUES OF DEDEKIND SUMS AND HARDY SUMS

  • Liu, Huaning
    • Journal of the Korean Mathematical Society
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    • v.46 no.1
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    • pp.187-213
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    • 2009
  • For a positive integer k and an arbitrary integer h, the classical Dedekind sums s(h,k) is defined by $$S(h,\;k)=\sum\limits_{j=1}^k\(\(\frac{j}{k}\)\)\(\(\frac{hj}{k}\)\),$$ where $$((x))=\{{x-[x]-\frac{1}{2},\;if\;x\;is\;not\;an\;integer; \atop \;0,\;\;\;\;\;\;\;\;\;\;if\;x\;is\;an\;integer.}\$$ J. B. Conrey et al proved that $$\sum\limits_{{h=1}\atop {(h,k)=1}}^k\;s^{2m}(h,\;k)=fm(k)\;\(\frac{k}{12}\)^{2m}+O\(\(k^{\frac{9}{5}}+k^{{2m-1}+\frac{1}{m+1}}\)\;\log^3k\).$$ For $m\;{\geq}\;2$, C. Jia reduced the error terms to $O(k^{2m-1})$. While for m = 1, W. Zhang showed $$\sum\limits_{{h=1}\atop {(h,k)=1}}^k\;s^2(h,\;k)=\frac{5}{144}k{\phi}(k)\prod_{p^{\alpha}{\parallel}k}\[\frac{\(1+\frac{1}{p}\)^2-\frac{1}{p^{3\alpha+1}}}{1+\frac{1}{p}+\frac{1}{p^2}}\]\;+\;O\(k\;{\exp}\;\(\frac{4{\log}k}{\log\log{k}}\)\).$$. In this paper we give some formulae on the mean value of the Dedekind sums and and Hardy sums, and generalize the above results.

MODULAR JORDAN TYPE FOR 𝕜[x, y]/(xm, yn) FOR m = 3, 4

  • Park, Jung Pil;Shin, Yong-Su
    • Journal of the Korean Mathematical Society
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    • v.57 no.2
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    • pp.283-312
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    • 2020
  • A sufficient condition for an Artinian complete intersection quotient S = 𝕜[x, y]/(xm, yn), where 𝕜 is an algebraically closed field of a prime characteristic, to have the strong Lefschetz property (SLP) was proved by S. B. Glasby, C. E. Praezer, and B. Xia in [3]. In contrast, we find a necessary and sufficient condition on m, n satisfying 3 ≤ m ≤ n and p > 2m-3 for S to fail to have the SLP. Moreover we find the Jordan types for S failing to have SLP for m ≤ n and m = 3, 4.

CHARACTERIZATIONS OF THE GAMMA DISTRIBUTION BY INDEPENDENCE PROPERTY OF RANDOM VARIABLES

  • Jin, Hyun-Woo;Lee, Min-Young
    • Journal of the Chungcheong Mathematical Society
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    • v.27 no.2
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    • pp.157-163
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    • 2014
  • Let {$X_i$, $1{\leq}i{\leq}n$} be a sequence of i.i.d. sequence of positive random variables with common absolutely continuous cumulative distribution function F(x) and probability density function f(x) and $E(X^2)$ < ${\infty}$. The random variables X + Y and $\frac{(X-Y)^2}{(X+Y)^2}$ are independent if and only if X and Y have gamma distributions. In addition, the random variables $S_n$ and $\frac{\sum_{i=1}^{m}(X_i)^2}{(S_n)^2}$ with $S_n=\sum_{i=1}^{n}X_i$ are independent for $1{\leq}m$ < n if and only if $X_i$ has gamma distribution for $i=1,{\cdots},n$.

Luminescent Characteristics of SrS:Cu,X Thin-Film Electroluminescent(TFEL) Deviecs depending on Coactivatiors (부활성제에 따른 SrS:Cu,X 박막 전계발광소자의 발광 특성)

  • Lee, Soon-Seok;Ryu, Chang-Keun;Lim, Sung-Kyoo
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.37 no.1
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    • pp.29-35
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    • 2000
  • Luminescent characteristics of SrS:Cu,X TFeL devices fabricated by electron-beam deposition system were studied. The SrS powders were used as the host materials and Cu, $CuF_2,\;Cu_2S$ or CuCl powders were added as the luminescent center. The emission spectra of the SrS:Cu,X TFEL devices strongly depended on coactivators. The luminance($L_{40}$) and efficiency(${\eta}_{20}$) of SrS:$Cu_2S$ TFEL device were 1443 cd/$m^2$ and 2.44 lm/w, respectively. Green color was observed from this TFEL device. The luminous efficiency of SrS:$Cu_2S$ TFEL device was higher than that of ZnS:Tb TFEL device, and it also could be good green phosphors for TFEL devices. The luminance($L_{40}$) and efficiency(${\eta}_{20}$) of SrS:CuCl TFEL device were 262 cd/$m^2$ and 0.26 lm/w, respectively. Blue color was emitted from this TFEL device.

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Study on the Electro-Optic Characteristics of $CdS_{1-x}Se_{x}$ Photoconductive Thin Films ($CdS_{1-x}Se_{x}$ 광도전 박막의 전기-광학적 특성연구)

  • Yang, D.I.;Shin, Y.J.;Lim, S.Y.;Park, S.M.;Choi, Y.D.
    • Journal of Sensor Science and Technology
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    • v.1 no.1
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    • pp.53-57
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    • 1992
  • We report the crystal growth and the electro-optic characteristics of $CdS_{1-x}Se_{x}$ thin films. $CdS_{1-x}Se_{x}$ thin films wire deposited on the alumina plate by electron beam evaporation technique in pressure of $1.5{\times}10^{-7}$ torr, voltage of 4kV, current of 2.5mA and substrate temperature of $300^{\circ}C$. The deposited $CdS_{1-x}Se_{x}$ thin films were proved to be a polycrystal with hexagonal structure through X-ray diffraction patterns. $CdS_{1-x}Se_{x}$ photoconductive films showed high photoconductivity after annealing at $550^{\circ}C$ for 30 minutes. And the films have been investigated the Hall effect, photocurrent spectra, sensitivity, maximum allowable power dissipation and response time.

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A NOTE ON SKEW DERIVATIONS IN PRIME RINGS

  • De Filippis, Vincenzo;Fosner, Ajda
    • Bulletin of the Korean Mathematical Society
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    • v.49 no.4
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    • pp.885-898
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    • 2012
  • Let m, n, r be nonzero fixed positive integers, R a 2-torsion free prime ring, Q its right Martindale quotient ring, and L a non-central Lie ideal of R. Let D : $R{\rightarrow}R$ be a skew derivation of R and $E(x)=D(x^{m+n+r})-D(x^m)x^{n+r}-x^mD(x^n)x^r-x^{m+n}D(x^r)$. We prove that if $E(x)=0$ for all $x{\in}L$, then D is a usual derivation of R or R satisfies $s_4(x_1,{\ldots},x_4)$, the standard identity of degree 4.

Preparation and Properties of Co$_{9-x}M_xS_8$(M = Ni, Rh, Ru, and Fe)

  • Kim, Kwan
    • Bulletin of the Korean Chemical Society
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    • v.7 no.2
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    • pp.102-105
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    • 1986
  • Samples with the nominal composition of $Co_{9-x}M_xS_8$(M = Ni, Rh, Ru, and Fe) were prepared, and their magnetic properties were measured. X-ray diffraction analysis showed that small amount of the elements Ni, Rh, and Fe could be incorporated into $Co_9S_8$ forming a homogeneous ${\pi}$-phase, whereas the Ru-incorporated sample could not be prepared in a single phase. The lattice parameter was observed to increase as other elements were incorporated into $Co_9S_8$. Samples incorporated with the elements of Ni, Rh, and Ru showed Pauli-paramagnetism while the Fe-incorporated sample exhibited weak ferromagnetism. The values of magnetic susceptibility for the Ni, Rh, Ru-incorporated samples were nearly the same as that of pure $Co_9S_8$.

ON PROPERTIES OF MINMAX SUBAUTOMATA

  • Park, Chin-Hong;Shim, Hong-Tae
    • Journal of applied mathematics & informatics
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    • v.16 no.1_2
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    • pp.595-604
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    • 2004
  • In this paper We shall give some characterizations for mX* derived from the relationships between S(m) and C(m). Also we shall discuss the minimal, maximal, strongly cyclic and minmaxCR-automata. There is an interesting part for the relationship between mX* and S(m). That is to say, that mX* is minimal has the same meaning as S(m) is strongly cyclic. We shall note that the minimality implies ‘ strongly cyclic’ and ‘strongly cyclic’ implies ‘cyclic’ and ‘cyclic’ implies ‘a MaxCR-automaton’.