• Journal of the Korean Wood Science and Technology
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• v.16 no.1
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• pp.21-44
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• 1988

As a way for the effective utilization of pallman chips and sawdusts, these furnish materials were combined with non-woody material of plastic (polypropylene) screen in board manufacturing to improve their weak physical and mechanical properties. The conventional boards were made with conditions of specific gravity 0.40, 0.55, 0.70, and 0.85, resin content 8, 10, 12 and 14%, and number of polypropylene screen 1, 2, 3 and 4, and press-lam boards were also manufactured. The physical and mechanical properties were measured and discussed on thickness swelling, bending modulus of rupture and elasticity, tensile strength, internal bond strength, and screw holding strength. The results obtained at this study were summarized as follows: 1. In thinckness swelling both of pallman chip board and sawdust board were improved by the increase of resin content, and press-lam boards showed lower thickness swelling than conventional boards. 2. Both the modulus of rupture and elasticity were increased with the increase of specific gravity, and press-lam boards showed higher modulus of rupture and elasticity than conventional boards. On the other hand, modulus of rupture was increased with the increase of number of polypropylene screen and resin content whereas these effects in modulus of elasticity was not recognized. 3. Tensile strength was increased with the increase of specific gravity, and the boards combined with polypropylene screen showed higher tensile strength than control boards. Also tensile strength was increased with the increase of number of polypropylene screen, and press-lam boards revealed higher tensile strength than conventional boards. 4. Internal bond strength was increased with the increase of specific gravity, and the boards combined with polypropylene screen were lower in internal bond strength than control boards. Also, the boards combined with odd number of polypropylene screen showed lower internal bond strength than those combined with even number of polypropylene screen. 5. Screw holding strength was increased with the increase of resin content and specific gravity but significant difference was not approved between boards combined with polypropylene screen and control boards. In press-lam boards, pallman chip boards of higher specific gravity but sawdust boards of lower specific gravity showed better screw holding strength than control boards.

• The Korean Journal of Financial Management
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• v.9 no.2
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• pp.1-29
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• 1992

자본자산(資本資産) 가격결정(價格決定)의 소비기저모형(消費基低模型)은 자본시장의 성질들을 깊이 있게 반영한 모형이지만 이 모형을 정립하는 데 사용된 효용함수의 형태가 주어지지 않고 있다. 이 효용함수의 형태는 실증분석을 통하여 결정되어야 한다. 이 논문에서는 소비기저모형에 사용될 수 있는 효용함수(效用函數)로서 기대효용함수(期待效用函數), 화폐효용함수(貨幣效用函數)와 비기대효용모형(非期待效用模型)을 상정하고 우리나라의 데이터를 사용하여 이 중 어느 함수(函數)가 우리나라의 투자활동과 자산의 가격결정에 적합한가를 실증적으로 분석하였다. 그 결과 상대적 위험기피계수는 대략 4이고 주관적 할인율이 0.8정도이며 소비기저모형(消費基低模型)을 정당화시키는 효용함수(效用函數)는 비기대(非期待) 모형(模型)임이 발견되었다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1872-1873
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• 2007

최근 유럽에서는 사용자와 운영자들의 요구에 부응하여 기존 DVB 위성 광대역 서비스에 대한 표준을 DVB-S에서 DVB-S2로 업그레이드 시켰다. DVB-S2는 ACM을 적용하여 여러 채널환경에서 기존의 표준보다 안정적인 전송과 높은 효율을 보여준다. DVB-S2 시스템은 FEC 알고리듬으로써 LDPC와 BCH를 사용하고 있다. LDPC는 R. G. Gallager에 의해 고안된 블록부호화 방식으로 검사행렬 H에서 1의 sparse 한 성질을 이용하여 큰 블록에서 더 좋은 성능을 발휘하도록 되어있다. 본 논문에서는 DVB-S2의 중요 서브시스템인 FEC블록 중 LDPC 복호기에 관하여 ACM을 적용하여 상위수준 시뮬레이션을 실시하였다. 실험결과 각 변조 방식 및 부호율에 따라서 BER이 SNR 0에서 14dB까지 넓게 분포함을 확인하였다. 그러므로 채널 환경에 따라 변조방식과 부호율을 달리하여 속도를 향상시키거나 데이터의 안정성을 높일 수 있다. 그리고 이 때 LDPC 복호기가 충분히 성능을 발휘함을 알 수 있다.

• Journal of the Korean Magnetics Society
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• v.10 no.5
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• pp.225-231
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• 2000

The crystallographic and magnetic properties of the sample F $e_{0.8}$ $Co_{0.18}$(BN)$_{0.02}$ synthesized by microwave arc-melting with the maximum power of 3.5 kW have been studied by the methods of an X-ray diffraction and the measurement of the magnetic hysteresis using the vibrating sample magnetometer at room temperature. The samples were prepared in a form of pellet pressed under the pressure of 9,000 N/c $m^2$, rolled coldly, and treated with the different temperatures. The X-ray diffraction pattern of pelleted sample shows that the crystal structure of the sample is bcc as same as that of Fe with a good uniformity. The X-ray diffraction pattern shows that a residual stress, which exists in the sample, is eliminated by final 90$0^{\circ}C$ annealing. As rolling rate and heat treatment temperature increases, the saturation magnetization and the remanence of the samples increase whereas the coercivity of the samples shows decrease. Also the saturation magnetization and the remanence of the samples were affected by rolling rate and rolling direction than heat treatment temperature, but the coercivity of the samples was affected by rolling rate and direction as well as heat treatment temperature. This means that a domain wall motion is easy due to elimination of a residual stress and an inclusion which exists in the sample by rolling and heat treatment and a local induced-magnetization easy axis was also formed to parallel to the rolling direction due to creation of the like-atom pairs across the slip plane by rolling......

• Journal of the Korean Magnetics Society
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• v.14 no.6
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• pp.219-223
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• 2004

L $i_{0.5}$F $e_{2.5-{\chi}}$R $h_{\chi}$ $O_4$ ($\chi$ = 0.25, 0.50, 0.75, 1.00) has been prepared by solid state reaction. Crystallographic and magnetic properties were investigated by Mossbauer spectroscopy, SQUID magnetometry, and x-ray diffraction. The crystal structure is found to be a cubic spinel structure with space group Fd3m for all the samples. The lattice constant $a_{0}$ increases from 8.3365 $\AA$ to 8.3932 $\AA$ with increasing Rh concentration $\chi$. The migration of Li ion has been confirmed by x-ray patterns and the results of applied field Mossbauer analysis. The temperature dependence of the absorption area of each site was analyzed with the Debye model for the recoil-free fraction. The Debye temperature for the octahedral sites is almost as large as for the tetrahedral sites, thereby suggesting similar inter-atomic binding forces for the octahedral and the tetrahedral sites. The saturated magnetic moment and the Mossbauer spectra taken at 4.2 K under the applied field (6 T) show that the spin structure of L $i_{0.5}$F $e_{2.5-{\chi}}$R $h_{\chi}$ $O_4$ is compatible with the collinear Neel Model.

• Journal of the Korean Ceramic Society
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• v.36 no.12
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• pp.1335-1341
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• 1999

The electrical conductivity ($\sigma$) of TiO2 doped with 0.05-4.0mol% Nb2O5 was measured in the oxygen partial pressure range of 10-17 to 100 atm and temperature range of 1100 to 130$0^{\circ}C$ to investigate the electrical properties and defect types. The oxygen partial pressure dependence of the electrical conductivity (log$\sigma$/logPo2) above 110$0^{\circ}C$ was divided into the four regions. From these experimental results the following defect regions were proposed ; 1) Magneli phase(extended defect) 2) reduced rutile region where intrinsic defect predominates 3) nearly stoichiometric region which is independent on the oxygen partical pressure and 4) overstoichiometric region which is not observed in pure TiO2 The electrical conductivity of Nb-doped TiO2 depended on the doping content the oxygen partial pressure and the measuring tem-perature.

• Korean Journal of Microbiology
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• v.25 no.1
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• pp.1-8
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• 1987

An extracellular $\beta$-1, 3-glucanase from Pseudomonas stutzeri KF 13 was purified about 390 with 26% recovery. The purified enzyme revealed a single band by polyacrylamide gel electrophoresis and SDS-polyacrylamide gel electrophoresis. The enzyme was stable in a pH 6.0 to 9.0, and relatively thermostable. The optimal pH and temperature on the enzyme activity were found to be 5.8 and 45.deg.C, respectively. The activation energy was calculated to be 16,130 cal per mole. The Km value for laminarin was found to be 3ng per ml and the molecular weight was determined to be 28,000 by gel filtration and 26,000 daltons by SDS-acrylamide gel electrophoresis. The enzyme was inhibited by 1.0mM of $Hg^{2+}$, and strongly inhibited by 1.0mM of p-chloromercuribenzoic acid.

• Journal of Life Science
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• v.13 no.4
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• pp.505-510
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• 2003

The extremely halophilic archaebacteriurn Haloarcular sp. EH-1 was isolated from solar salts. Halophages found in Haloarcular sp. EH-1 were isolated from fermented anchovy sauce. Halophages were isolated from fermented anchovy sauce using Haloarcular sp. EH-1 as a host bacterium. The isolated halophage produced 0.5∼l.0 mm in diameter clear plaques. The halophage consists of an symmetrical head, measuring 68 nm in diameter, and a contractile tail, 100 nm long and base plates were observed. Total size of phage DNA genome obtained 20 Kbp and its sequence homology was 52.87% with H. Salinarium.

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.18-22
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• 2006

Effects of V substitution of Fe on the magnetic properties of $Fe_3O_4$ have been investigated by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), conversion electron Mossbauer spectroscopy (CEMS), and vibrating sample magnetometry (VSM) measurements on sol-gel-grown films. XRD data indicates that the $V_xFe_{3-x}O_4$ films maintain cubic structure up to x=1.0 with little change of the lattice constant. Analyses on V 2p and Fe 2p levels of the XPS data indicate that V exist as $V^{3+}$ mostly in the $V_xFe_{3-x}O_4$ films with the density of $V^{2+}$ ions increasing with increasing V content. Analyses on the CEMS data indicate that $V^{3+}$ ions substitute tetrahedral $Fe^{3+}$ sites mostly, while $V^{2+}$ ions octahedral $Fe^{2+}$ sites. Results of room-temperature VSM measurements on the films reveal that the saturation magnetization for the x=0.14 sample is larger than that of $Fe_3O_4$, while it becomes smaller than that of $Fe_3O_4$ for $x{\geq}0.5$. The coercivity of the $V_xFe_{3-x}O_4$ films is found to increase with x, attributed to the increase of anisotropy by the substitution of $V^{2+}(d^3)$ ions into the octahedral sites.

• Applied Biological Chemistry
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• v.12
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• pp.25-31
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• 1969

The characteristics of crude enzyme produced from Trichoderma viride($O_2-1$) which isolated from half spoiled Locust acacia wood (Robinia Pseudacacia Linne) were examined in this paper. The results obtained were summarized as follows: 1) As a results of enzymatic action on several cellulose substrate it was found that there were some sorts of cellulase in crude enzyme. 2) The activity of C.M.C. ase and ${\beta}-glucosidase$ were decreased in accordance with increasing concentration of substrate, and filter paper saccharifying enzyme relatively increased in accordance with increasing concentration of substrate and enzyme in couse of time. 3) The optimal pH of each enzyme was 5.0 and the range of stability on pH generally from 3 to 6. 4) In disintegrating activity on filter paper, in decomposing activity on C.M.C. and $p-nitrophenyl-{\beta}-D-glucoside$, and in saccharifying activity on filter paper, the optimal temperatures were $50^{\circ}C.,\;60^{\circ}C,\;and\;65^{\circ}C$. 5) The order of stability on temperature was as follow; saccharifying activity on filter paper decomposing activity on C.M.C. disintegrating activity on filter paper>decomposing activity on $p-nitrophenyl-{\beta}-D-glucoside$. 6) The activity of the enzymes was inhibited with mercuric and silver ion, and activated with potassium.