• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.1
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• pp.14-19
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• 2013

We have successfully synthesized $Bi_{4-x}La_xTi_3O_{12}$ (x~2) having Aurivillius-type layered perovskite structure from exfoliated layered perovskite oxide of $K_2La_2Ti_3O_{10}$ with Ruddlesden-Popper structure. The reaction between the exfoliated lanthanum titanate nanosheets and BiOCl nanocrystal resulted in the formation of polycrystalline $Bi_{4-x}La_xTi_3O_{12}$ (x~2) after heating above $700^{\circ}C$. Colloidal suspension of the nanosheets could be obtained by intercalating ethylamine (EA) into the protonated lanthanum titanate, $H_2La_2Ti_3O_{10}$, derived from $K_2La_2Ti_3O_{10}$. Transmission electron microscopic (TEM) analysis show that the exfoliated lanthanium titanate nanosheets have a thickness of a few nano meters. According to X-ray diffraction (XRD) analysis, the exfoliated lanthanium titanate was found to be transformed into $Bi_{4-x}La_xTi_3O_{12}$ (x~2) after restacking with BiOCl and subsequent thermal treatment at > $700^{\circ}C$.

• The KIPS Transactions:PartC
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• v.17C no.4
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• pp.335-346
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• 2010

Mac OS X is the Computer Operating System that develop in Apple Inc. Mac OS X is the successor to Mac OS 9 Version which had been Apple's primary operating system since 1984. Recently, Mac OS X 10.6 (Snow Leopard) has been manufactured and is distributed to user. Apple's Mac OS X Operating System is occupying about 10% in the world Operating System market share. But, Forensic tools that is utilized on digital forensic investigation can not forensic analysis about Mac OS X properly. To do forensic investigation about Mac OS X, information connected with user's action and trace can become important digital evidence in Operating System. This paper presents way about user trace data acquisition methodology in Mac OS X.

• Journal of the Chungcheong Mathematical Society
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• v.29 no.2
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• pp.287-328
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• 2016

In the current work, we define and find the general solution of the decic functional equation g(x + 5y) - 10g(x + 4y) + 45g(x + 3y) - 120g(x + 2y) + 210g(x + y) - 252g(x) + 210g(x - y) - 120g(x - 2y) + 45g(x - 3y) - 10g(x - 4y) + g(x - 5y) = 10!g(y) where 10! = 3628800. We also investigate and establish the generalized Ulam-Hyers stability of this functional equation in Banach spaces, generalized 2-normed spaces and random normed spaces by using direct and fixed point methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.6
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• pp.548-557
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• 1992

This paper presents how X.25 state machines are defined and procedures are implemented Into the TDI-10 switching system, which Is being developed as an ISDN exchange in Korea.Packet switching is an in important aspect of I SDN. Packet swichedd services in ISDN are defined by X.:31, which provides for the use X.f,j over ISDN B and D-channels between a user and an X.25packet handler. To implement X.2E into an ISDN exchange which Includes a packet handler, X.25state machines and procedures should be adj usted within the ISDN exchange.

• Communications of the Korean Mathematical Society
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• v.9 no.3
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• pp.539-545
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• 1994

Let $q = p^r$, where p is a prime. A polynomial $f(x) \in GF(q)[x]$ is called a permutation polynomial (PP) over GF(q) if the numbers f(a) where $a \in GF(Q)$ are a permutation of the a's. In other words, the equation f(x) = a has a unique solution in GF(q) for each $a \in GF(q)$. More generally, $f(x_1, \cdots, x_n)$ is a PP in n variables if $f(x_1,\cdots,x_n) = \alpha$ has exactly $q^{n-1}$ solutions in $GF(q)^n$ for each $\alpha \in GF(q)$. Mullen ([3], [4], [5]) has studied the concepts of local permutation polynomials (LPP's) over finite fields. A polynomial $f(x_i, x_2, \cdots, x_n) \in GF(q)[x_i, \codts,x_n]$ is called a LPP if for each i = 1,\cdots, n, f(a_i,\cdots,x_n]$ is a PP in $x_i$ for all $a_j \in GF(q), j \neq 1$.Mullen ([3],[4]) found a set of necessary and three variables over GF(q) in order that f be a LPP. As examples, there are 12 LPP's over GF(3) in two indeterminates ; $f(x_1, x_2) = a_{10}x_1 + a_{10}x_2 + a_{00}$ where $a_{10} = 1$ or 2, $a_{01} = 1$ or x, $a_{00} = 0,1$, or 2. There are 24 LPP's over GF(3) of three indeterminates ; $F(x_1, x_2, x_3) = ax_1 + bx_2 +cx_3 +d$ where a,b and c = 1 or 2, d = 0,1, or 2.

• Bulletin of the Korean Mathematical Society
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• v.49 no.3
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• pp.529-572
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• 2012

A basis of a subspace of $S_4({\Gamma}_0(79))$ is given and the formulas for the number of representations of positive integers by some direct sums of the quadratic forms $x^2_1+x_1x_2+20x^2_2$, $4x^2_1{\pm}x_1x_2+5x^2_2$, $2x^2_1{\pm}x_1x_2+10x^2_2$ are determined.

• Journal of the Korean Dietetic Association
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• v.12 no.2
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• pp.172-184
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• 2006

This study was aimed to provide safety management guidance by evaluating the microbial quality of cooked dried-seafoods in school foodservice operations. Nineteen seafood items were collected from six elementary schools, those were dried-anchovy, dried-seaweed and dried-fish, which were classified as cooking process. The temperatures at receiving and after cooking were measured and the analyses of cooking processes and microbial quality were performed. The temperatures of all foods after cooking were higher than the temperature limit of $74\^circC$. The number of total aerobic bacteria and S. aureus in dried-anchovy over the limit of $10^5$ and even the level of S. aureus was found to be unsatisfactory. The count of total aerobic bacteria was 2.1x$10^8$ CFU/g and the number of total aerobic bacteria after cooking was over the limit in one school. The level of E. coli (3.1x$10^3$ CFU/g) was over the limit at one school and the number of S. aureus (1.2×$10^4$ CFU/g) was considered as unacceptable. Dried- tangle and green laver were contaminated with total aerobic bacteria showing the over the limit. The numbers of total aerobic bacteria in dried- filefish, pollack and squid were 4.3x$10^6$, 3.4x$10^6$-3.9x$10^7$ and 4.6x$10^5$-4.1x$10^7$ CFU/g, respectively, which were in acceptable or unsatisfactory level. The E. coli in dried- filefish and pollack were over the limit. The total aerobic bacteria levels, 4.6x$10^5$-1.5x$10^6$ CFU/g in dried-pollack and 8.0x$10^5$-2.2x$10^7$ CFU/g in dried-squid, were over the limit after cooking except dried-filefish. The E. coli levels, 4.3x$10^3$ CFU/g in dried-filefish and 2.5x$10^2$ CFU/g in dried-pollack, were over the limit of $10^2$ CFU/g. The numbers of Enterobacteriaceae were either acceptable (3.3x$10^3$ CFU/g) or unsatisfactory (1.6x$10^4$ CFU/g) level in dried-pollack. S. aureus was unsatisfactory level (6.5x$10^4$ CFU/g) in dried-filefish while unacceptable in dried-pollack both before and after cooking. Unacceptable levels of S. aureus, 2.4x$10^4$ and 1.3x$10^5$ CFU/g were found from two schools, respectively. These results suggest that the contamination of raw materials and the seasonings added after cooking should be controlled to manage the microbial safety of cooked dried-seafoods.

• Nuclear Engineering and Technology
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• v.3 no.2
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• pp.65-75
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• 1971

The gamma-ray shielding effects of magnetite concretes have been measured using a broad beam Co-60 gamma-ray source. Mathematical formulae for a trans-mission ratio-to-shield thickness relation were derived from the attenuation curve obtained experimentally and are I (x) = I (ο) exp(-$\mu$X) exp(1.03$\times$10$^{-1}$ X-3.38$\times$10$^{-3}$ X$^2$＋5.29$\times$10$^{-5}$ X$^3$) when X< 20 cm, I (x) =I (ο) exp(-$\mu$X) exp(4.66$\times$10$^{-2}$ X＋2.12$\times$10$^{-1}$ ) when X＞20 cm. Here I (x) is radiation intensity after passing through a thickness X of absorber, I(o) is the initial radiation intensity, $\mu$ is the linear attenuation coefficient of magnetite concrete and is given by (0.0532$\rho$＋ 0.0083)$^{4)}$ $cm^{-1}$ / in accordance with an earlier study, and X is the thickness of absorber. In addition, a model shield which is a rectangular magnetite concrete box with walls of 8cm thickness walls and internal demensions of 40$\times$40$\times$40 cm was constructed and its shielding effect has been measured. The emergent radiation flux appears to be greater with this configuration than with a slab shield of equal thickness.

• Journal of the Korean Magnetics Society
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• v.10 no.5
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• pp.220-224
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• 2000

Ultra-fine $Co_{1+x}$F $e_{2-}$2x/ $Ti_{x}$ $O_4$ferrite powders have been prepared by the sol-gel method. The crystallographic and magnetic properties of the sample have been investigated by means of x-ray diffraction, Mossbauer spetroscopy and vibrating sample magnetometry. The formation of nano crystallized particles is confirmed. The x-ray diffractions of all samples with various compositions clearly indicate the presence of spinel structure. The Mossbauer spectra could be fitted as the superposition of two sextets due to F $e^{3+}$ A-site and B-site. The IS and QS values nearly constant with substituted Co-Ti contents, whereas $H_{hf}$ of B-site decreases with increasing Co-Ti substitution in $Co_{1+x}$F $e_{2-}$2x/ $Ti_{x}$ $O_4$. The magnetic behaviour of powders shows that the saturation magnetization and the coercivity decrease with increasing x in $Co_{1+x}$F $e_{2-}$2x/ $Ti_{x}$ $O_4$.$.X>.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.5
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• pp.706-711
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• 1986

The AgGa1-xInxSe2 films are deposited by a flash evaporation method onto pyrex glass substrates at temperatures between 5\ulcorner and 360\ulcorner. The single crystalline films which have X-ray diffraction peak of only (112) plane are preared at substrate temperature above 360\ulcorner. The prepared AgGa 1-xInxSe2 films are high photosensitive. The temperature coefficients of energy gap are found to be (-1.2~-4.0)x10**4 eV/K and (-3.1~-5.2)x10**-4 eV/K, and that of peak energy of spectral photoresponse curve are found to be (-1.1 ~ -3.0)x10**-4 eV/K(50K~100K) and (-2.4~-5.1)x10**-4 eV/K(100K~300K).