• The Korean Journal of Mycology
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• v.23 no.3 s.74
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• pp.197-201
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• 1995

For 2 years $(1993{\sim}1994)$, study on development of cheap medium for Pleurotus ostreatus revealed that paper sludge contain more CaO and similar T-C, T-N, $P_2O_5$, MgO but less $K_2O$ than any other medium material in chemical property. Mixed treatment (rice straw + paper sludge 10, 30, 50%, cotton waste + paper sludge 10, 30, 50%, cotton waste + rice hull 20 + paper sludge 10, 30, 50, 70%) is similar or fast a little in mycelial growth and is similar or fast $1{\sim}2$ day in period of primordia formation than cotton waste medium, and in the yield to each medium type also increased but excepted in rice hull 20% + paper sludge 70%, especially mixed medium at 7:3 ratio of cotton waste and paper sludge is best treatment because it is increased to 21%. In economical analysis, mixed medium at 7:3 ratio of cotton waste and paper sludge is increased to 50% compared to cotton waste medium in relative income.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.939-947
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• 2010

The LDPC(Low-Density Parity-Check) code, which is one of the channel encoding methods in IEEE 802.11n wireless LAN standard, has superior error-correcting capabilities. Since the hardware complexity of LDPC decoder is high, it is very important to take into account the trade-offs between hardware complexity and decoding performance. In this paper, the effects of LLR(Log-Likelihood Ratio) approximation on the performance of MSA(Min-Sum Algorithm)-based LDPC decoder are analyzed, and some optimal design conditions are derived. The parity check matrix with block length of 1,944 bits and code rate of 1/2 in IEEE 802.11n WLAN standard is used. In the case of $BER=10^{-3}$, the $E_b/N_o$ difference between LLR bit-widths (6,4) and (7,5) is 0.62 dB, and $E_b/N_o$ difference for iteration cycles 6 and 7 is 0.3 dB. The simulation results show that optimal BER performance can be achieved by LLR bit-width of (7,5) and iteration cycle of 7.

• Journal of the Korean Statistical Society
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• v.23 no.2
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• pp.239-250
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• 1994

In this paper, we prove a strong large deviations theorem for the ratio of independent randoem variables with error rate of $O(n^{-1})$. To obtain our results we use the inversion formula for the tail probability and apply the Chaganty and Sethuraman's (1985) approach.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.2
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• pp.209-218
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• 2012

Recently, as reinforced water quality standards for wastewater has been announced, more efficient and more powerful wastewater treatment processes are required rather than the existing activated sludge process. In order to meet this demands, we evaluate Task 1-4 about lab scale $A_{2}O$　process using biofilm media. Task 1, 2, and 3 use 'Module A' which has 4 partitions (Anoxic/Anerobic/Oxic/Oxic). Task 4 uses 'Module B' which has 2 partitions including a denitrification reactor with an Inclined plug flow reactor (IPFR) and a nitrification reactor with biofilm media. The denitrification reactor of Module B is designed to be upward flow using IPFR. The result of evaluating at each Task has shown that attached growth system has better capacity of removal efficiency for organic matter and nitrogen with the exception of phosphorus.　Task 4 which has the most outstanding removal efficiency has 90.5% of $BOD_{5}$ removal efficiency, 97.8% of ${NH_4}^{+}-N$ removal efficiency, 65% of T-N removal efficiency and 92% of T-P removal efficiency with additional chemical phosphorus removal system operated at HRT 9hr, Qi:Qir 1:2, and BOD/T-N ratio 2.7.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.73-79
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• 1999

The superstructured $Li_{4/3}Ti_{5/3}O_4$ was prepared by sol-gel process using a mixed solution of lithium acetate (LA) and titanium n-butoxide (TNB). The gel phase was obtained by adding ammonia water ($NH_4OH/TNB$ mole ratio of 0.35) and water ($H_2O/TNH$ mole ratio of 3.5) into the clear sol that was prepared after mixing TNB/LA mole ratio of 5/4 with AA/TNB mole raio of 0.125. It was found that the most suitable $Li_{4/3}Ti_{5/3}O_4$ was obtained by heat treatment of xerogel at $600^{\circ}C$ for 30 hrs. The synthesized $Li_{4/3}Ti_{5/3}O_4$ showed an initial discharge capacity of 174 mAh/g and the capacity loss of about 27.3% during 25 cycles in Li/1M $LiClO_4(in\;PC)/Li_{4/3}Ti_{5/3}O_4$ at current density of $0.15mA/cm^2$ and the voltage range of 0.5~3.0 V.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.6
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• pp.339-344
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• 2017

An all-transparent photodetector was fabricated by structuring $Cu_2O$/ZnO/AZO/ITO on a glass substrate. The visible-range transmittance was as high as 80%, which ensures clear vision forhuman eyes. High-transparency metal conductive oxides (p-type $Cu_2O$ and n-type ZnO) were appliedto form the transparent p/n junction. The functional AZO layer was adopted to improve the transparent photodetector performance between the ZnO and ITO, improving the photoresponses because of its electrical conductivity. To clarify the AZO functionality, a comparator device was prepared without the AZO layer in the formation of $Cu_2O$/ZnO/ITO/Glass. The $Cu_2O$/ZnO/AZO/ITO device provided a rectifying ratio of 113.46, significantly better than the 9.44 of the $Cu_2O$/ZnO/ITO device. In addition, the $Cu_2O$/ZnO/AZO/ITO device's photoresponses at short wavelengths were better than those of the comparator. The functioning AZO layer provides ahigh-performing transparent Cu oxide photodetector and may suggest a route for the design of efficient photoelectric devices.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1428-1430
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• 1996

Thin Silicon oxynitride(SiON) films have been chemically deposited using 193nm ArF Excimer Laser CVD, with $Si_{2}H_{8}$, $N_{2}O$, and $NH_3$ as the reactive gases and $N_2$ as the carrier gas. Experimental results show that deposition rate and refractive index have a strong dependence on substrate temperature, chamber pressure, gas ratio, laser power and laser beam height. Electrical characterization of oxynitride films demonstrates that for $NH_{3}/N_{2}O$ flow ratios ranging from 0.25 to 1, the leakage currents, the interface trap density and the capacitances (dielect ric constant) increase and the dielectric breakdown fields decrease

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.340-342
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• 1995

We prepared $LiCo_{1-x}Ni_{x}O_2$ by reacting stoichiometric mixture of LiOH.$H_2O$, $CoCO_3$.$xH_2O$ and $Ni(OH)_2$(mole ratio respectively) and heating at $850^{\circ}C$ for 5n. In the result of X-ray diffraction analysis, along fluctuation of the function of x in $LiCo_{1-x}Ni_{x}O_2$(003) peak and (104) peak indensities and ratio were varied. We awared through XRD that from 0 to 0.5 at x in $LiCo_{1-x}Ni_{x}O_2$ is well formed for hexagonal structure at one step heat treatment($850^{\circ}C$), but if Ni involve at $LiCo_{1-x}Ni_{x}O_2$ hexagonal structure is not well formed. In the result of charge/discharge tests charge/discharge capacity and effiency is different about various cathode. Therefore, the appropriate charge/discharge method must be selected for good characteristics.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.130-130
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• 2016

Bioinspired hierarchical nanostructures for self-cleaning s-tnwjurface and SERS substrates are investigated. The multi-level hierarchy is combined with CuO nanowire and additional nanoscale structures. CuO nanowire, which has extremely high aspect ratio, serves as a base structure of multi-level hierarchy and additional flower like structures are placed on the CuO nanowires. Since as-fabricated CuO nanostructures are hydrophilic, the surface is coated with perfluorooctyltrichlorosilane in order to change its wetting property to hydrophobic. While those CuO based nanostructures have a sufficient roughness for superhydrophobic characteristics, hierarchical nanoflowers on nanowire structures lead to a self-cleaning surface. Furthermore, flower like nanostructures provide reentrant curvatures, thus enabling oleophobic property. The surfaces has a repellency even for a tiny droplet (10 nL) of low surface tension liquids (~35 mN/m). On the on hands, nanoflowers provide many number of nanoscale gaps. After a thin layer of silver is deposited on the surface of CuO nanostructures, those nanoscale gaps act as hot-spot for surface enhanced Raman scattering (SERS). To analyze SERS enhancement of the surfaces, Raman shift is measured with varying molar density of 4-Mercaptopyridine from mM to pM. From these results, hierarchical CuO nanostructures are suitable for self-maintenance and cost effective SERS sensing applications.

• 전기의세계
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• v.21 no.6
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• pp.17-20
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• 1972

The magnetic properties of Ba-Ferrite ( $M^{+2}$O.nF $e_{2}$ $O_{3}$ is highly improved under the condition of composition ratio n=4.4 when B $i_{2}$ $O_{3}$ is added to Ferrite, the adding amount and sintering temperature which affect the magnetic properties were investigated and the following results; were obtained; 1. Magnetic properties are varied with B $i_{2}$ $O_{3}$ content and singering temperature, and coercive force and residual induction can be improved with B $i_{2}$ $O_{3}$. 2. The optimal content of B $i_{2}$ $O_{3}$ amount is about 4 mol %, 3. Without the addition of B $i_{2}$ $O_{3}$, the optimal sintering temperature is about 1300.deg. C, but when 4 mol % of B $i_{2}$ $O_{3}$ is added, the optimal sintering temperature falls to the range of 900.deg. C to 1100.deg. C and it also improves magnetic properties. 4. Residual induction increases as the singering temperature is raised to 1100.deg. C. Coercive force also increased as the sintering temperature is raised to 1000.deg. C, but it rapidly decreases when sintering temperature goes beyond 1000.deg. C. 5. Only a negligible change may be noticed in the decrease of Curie temperature by the addition of about 4 mol % of B $i_{2}$ $O_{3}$.