• 한국음향학회:학술대회논문집
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• 한국음향학회 1994년도 제11회 음성통신 및 신호처리 워크샵 논문집 (SCAS 11권 1호)
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• pp.199-204
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• 1994

In this paper, we researched abut CELP speech coding algorithm using efficlent pseudo-stochastic block codes, adaptive-codebook and improved fixed-gain codebook. The pseudo-stochastic block codes refer to stochastically populated block codes in which the adjacent codewords in an innovation codebook are non-independent. The adaptive-codebook was made with previous prediction speech data by storage-shift register. This CELP coding algorithm enables the coding of toll quality speech at bit rates from 4.8kbits/s to 9.6 kbits/s. This algorithm was realized TMS320C30 microprocessor in realtime.

• International Journal of Precision Engineering and Manufacturing
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• 제3권2호
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• pp.22-32
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• 2002

V-notched crack problems can be formulated as eigenvalue problems. The problem ova v-notched crack in anisotropic and/or pseudo-isotropic dissimilar materials was formulated as an eigenvalue problem to discuss stress singularities. The eigenvalue problem was served by the commercial numerical program; MATHEMATICA. The specific data of eigenvalues possessing the stress singularity were obtained. Stress singularities fur v-notched cracks in anisotropic and/or pseudo-isotropic dissimilar materials were discussed according to the relation between wedge angle and material property. It was shown that there are three cases of eigenvalues possessing the stress singularity; one real, two real and one complex.

• Carbon letters
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• 제10권1호
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• pp.23-32
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• 2009

The adsorption of phenolic compound resorcinol on activated carbons prepared from Moringa oleifera (Drumstick bark) has been investigated. Activated carbon was prepared by impregnating Moringa oleifera with 50% phosphoric acid in the ratio of 1:1 and 1:2(w/w), designated as MOAC1 and MOAC2. Equilibrium and isotherm studies were carried out. The influences of variables such as contact time, initial concentration of resorcinol, carbon dosage in the solution on percentage adsorption and adsorption capacity of the bark have been analysed. The equilibration time was found to be 4 h. Kinetics of resorcinol onto activated carbons was checked for pseudo first order and pseudo second order model. It was found that the adsorption of resorcinol follows pseudo second order kinetics for both MOAC1 and MOAC2. The isotherm data were correlated with isotherm models, namely Langmuir and Freundlich. Adsorption isotherms were satisfactorily fitted by both the Langmuir and Freundlich model for MOAC1 and MOAC2.

• 약학회지
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• 제40권4호
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• pp.418-421
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• 1996

From the ethanol extract of the whole plant of Aconitum pseudo-laeve var. erectum Nakai, three new aromatic amides, methyl-N-acetyl anthranilate, methyl-N-(3-ethox ycarbonylpropionyl)anthranilate, methyl-N-(3-methoxycarbonylpropionyl) anthranilate were isolated and characterized on the basis of spectral data.

• 한국통신학회논문지
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• 제41권12호
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• pp.1756-1758
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• 2016

의사거리는 GPS 수신기의 위치를 결정하기 위한 오차를 포함해 측정된 GPS 위성과 수신기 사이의 거리이다. 재방송 재밍기는 GPS 수신기에 가까이 있을 때 효과적으로 동작한다. 본 논문에서는 재방송 재밍의 원리를 효과적으로 이해하기 위해 근접한 GPS 수신기의 의사거리 차를 분석한다.

• Ocean Science Journal
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• 제43권1호
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• pp.25-30
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• 2008

Potentially toxic diatoms Pseudo-nitzschia calliantha and P. fraudulenta were found in bottle samples of phytoplankton collected in Amurskii Bay (East/Japan Sea) and in the coastal waters of Sakhalin Island (East/Japan Sea and Sea of Okhotsk) in different seasons during 2002-2006. The mass development of these species occurred in October and November 2002 at water temperatures of $6-16^{\circ}C$ and salinities of 28.8-33.5 PSU. The highest concentrations of P. calliantha and P. fraudulenta were about $2{\times}10^5\;cells\;L^{-1}$ and $1.5{\times}10^5\;cells\;L^{-1}$, respectively. P. fraudulenta was found for the first time in the Russian waters of the East/Japan Sea. Morphological descriptions of these species based on observation with light and electron microscopy and information on their ecology are presented. Data on the geographical distribution of these species are supplemented.

• Membrane and Water Treatment
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• 제8권1호
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• pp.73-88
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• 2017

Adsorption kinetics of aqueous ferric ion ($Fe^{3+}$) onto bio-natural rice grains (BRG) have been studied in a batch system. The influence of contact time (0-180 minutes), the dosage of BRG adsorbent (10, 20, 40, and $60gL^{-1}$), and ambient temperature (27, 37, 47, and $57^{\circ}C$) for the adsorption system have been reported. The equilibrium time achieved after 20 minutes of adsorption contact time. The maximum removal of ferric ion is 99% by using $60gL^{-1}$ of BRG, $T=37^{\circ}C$, and $50mgL^{-1}$ ferric ion solution. Adsorption kinetic and diffusion models, such as pseudo-first order, pseudo-second order, and Weber-Morris intra-particle diffusion model, have been used to describe the adsorption rate and mechanism of the ferric ion onto BRG surface. The sorption data results are fitted by Lagergren pseudo-second order model ($R^2=1.0$). The kinetic parameters, rate constant, and sorption capacities have been calculated. The new information in this study suggests that BRG could adsorb ferric ion from water physiosorption during the first 5 minutes. Afterward, the electrostatic interaction between ferric ion and BGR-surface could take place as a very weak chemisorptions process. Thus, there is no significant change could be noticed in the FTIR spectra after adsorption. I recommend producing BGR as a bio-natural filtering material for removing the ferric ion from water.

• Carbon letters
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• 제9권3호
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• pp.181-187
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• 2008

Batch sorption experiments were carried out for the removal of metylene blue from its aqueous solution using $H_3PO_4$ activated Acacia arabica carbon (AAC). The prepared activated carbon was characterized and was found as an effective adsorbent material. The operating variables studied were initial metylene blue concentration, AAC concentration and solution pH. AAC activated carbon posses a maximum sorption capacity for the range of initial dye concentrations studied (60~100 mg $L^{-1}$). The sorption kinetics were analyzed using reversible first order kinetics, second order, reversible first order, pseudo-first order, and pseudo-second order model. The sorption data tend to fit very well in pseudo-second order model for the entire sorption time. The average pseudo-second order rate constant, $K_{II}$ and regression coefficient value were determined to be 0.0174 mg $g^{-1}$ $min^{-1}$ and 0.9977. The biosorption process also fit well to reversible I order kinetics with a regression coefficient of 0.9878.

• Carbon letters
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• 제11권3호
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• pp.224-234
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• 2010

Four activated carbons were produced by two-stage process as followings; semi-carbonization of indigenous biomass waste, i.e. cotton stalks, followed by chemical activation with KOH under various activation temperatures and chemical ratios of KOH to semi-carbonized cotton stalks (CCS). The surface area, total pore volume and average pore diameter were evaluated by $N_2$-adsorption at 77 K. The surface morphology and oxygen functional groups were determined by SEM and FTIR, respectively. Batch equilibrium and kinetic studies were carried out by using a basic dye, methylene blue as a probe molecule to evaluate the adsorption capacity and mechanism over the produced carbons. The obtained activated carbon (CCS-1K800) exhibited highly microporous structure with high surface area of 950 $m^2/g$, total pore volume of 0.423 $cm^3/g$ and average pore diameter of 17.8 ${\AA}$. The isotherm data fitted well to the Langmuir isotherm with monolayer adsorption capacity of 222 mg/g for CCS-1K800. The kinetic data obtained at different concentrations were analyzed using a pseudo-first-order, pseudo-second-order and intraparticle diffusion equations. The pseudo-second-order model fitted better for kinetic removal of MB dye. The results indicate that such laboratory carbons could be employed as low cost alternative to commercial carbons in wastewater treatment.

• Environmental Engineering Research
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• 제16권2호
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• pp.55-60
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• 2011

The removal of hexavalent chromium from aqueous solutions onto modified holly sawdust was studied at varying initial hexavalent chromium concentrations, adsorbent doses, pHs and contact times. The removal of hexavalent chromium from aqueous solutions increased with increasing adsorbent dosage and contact time. The percentage of hexavalent chromium removed from the aqueous solutions decreased with increasing hexavalent chromium concentration and pH of the solution. The kinetics of the adsorption of hexavalent chromium onto modified holly sawdust was analyzed using pseudo first-order and pseudo second-order models. The pseudo second-order model described the kinetics of adsorption of hexavalent chromium. The Langmuir and Freundlich isotherm models were used for modeling of the adsorption equilibrium data. The Langmuir isotherm model well described the equilibrium data for the removal of hexavalent chromium by modified holly sawdust. The obtained maximum adsorption capacity was 18.86 mg/g at pH 7. The results showed that modified holly sawdust can be used as a low cost adsorbent for the treatment of aqueous solutions containing chromium.