• The Journal of the Acoustical Society of Korea
• /
• v.18 no.6
• /
• pp.3-8
• /
• 1999

In this paper, we propose a new active noise control system that cancels the only noise signal from the mixture selectively. A blind source separation realized by a dynamic recurrent neural network is used as a preprocessor of the active noise control system and separates the desired signal and the noise signal. The active noise control system adaptively generates an anti-noise signal to remove the only noise signal separated by the blind source separation. Computer simulation results show that the proposed scheme is effective to construct a selective attention system.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2008.05a
• /
• pp.198-201
• /
• 2008

• Journal of the Korean Chemical Society
• /
• v.25 no.1
• /
• pp.54-616
• /
• 1981

• Journal of Welding and Joining
• /
• v.12 no.4
• /
• pp.141-150
• /
• 1994

The residual stress is inevitably introduced into composites because of the mismatch of the coefficient of thermal expansion, and it is different in each phase. The X-ray technique can detect separately the stress in each phase, so will wield useful information for analyzing the toughening mechanisms of composites. In order to apply the law of mixture to alloy steels with composite microstructures, two phase stainless steel, consisted of ferrite (.alpha.-Fe) and austenite (.gamma.-Fe) structures, was selected. The tensile elastic deformation was loaded, and then the X-ray diffraction technique was used to measure the X-ray elastic constants, the X-ray stress constants and the phase stresses. The law of mixture was investigated and the separation of macrostress and microstress was carried out. The phase stresses (the residual stresses of phase) in each phase, which were measured by X-ray technique, was directly proportional to the applied stress. The macrostress calculated from the phase stresses by using the law of mixture was nearly equal to the applied stress.

• Progress in Superconductivity and Cryogenics
• /
• v.12 no.1
• /
• pp.66-70
• /
• 2010

The operational temperature range of thermosiphon is generally limited from the critical point to the triple point of the working fluid to maintain two-phase state. Thermosiphon with mixed working fluid has a potential to widen the operational temperature range. In this study, the physical behavior of mixed working fluid during the transient operation of thermosiphon was analyzed with temperature-mole fraction diagram. The condenser and the evaporator temperature variations were explained by the dew line and the bubble line of the mixture. It is encouraging that the thermosiphon operation commences early with larger fraction of high boiling point component, but the temperature gap between the condenser and the evaporator due to the separation of two components has a negative effect on the officient cool down process.

• Journal of the Korean Chemical Society
• /
• v.17 no.6
• /
• pp.428-433
• /
• 1973

The quantitative separations of a mixture containing equal amount of each anion such as Si(IV), As(V), P(V), S(VI), W(VI) and Cr(VI) are carried out by the elution through 20${\times}3.14cm^2$ column of anion exchange resin, Dowex 1${\times}$8. The eluents are a mixture of 0.07 M hydrochloric acid and 0.03 M sodium chloride (pH = 1.30) for Si(IV), As(V) and P(V) species, a mixture of 0.6 M sodium chloride and 0.3 M sodium hydroxide for S(VI), W(VI) and Cr(VI) species, and 0.1 N sodium sulfite (pH = 3.48) for P(V) and As(V) species. The subsidiary anions in a standard mixture such as Si(IV), As(V), S(VI), P(V) and W(VI) are separated together from large amount of Fe(III) by the elution through 30cm${\times}3.14cm^2$ column of the resin, Dowex${\times}$50w${\times}$12, using a mixture of 0.1 M sodium nitrate and 2 percent dimethylsulfoxide aqueous solution as an eluent. Si(IV), As(V), S(VI), P(V) and W(VI) eluted together are separated quantitatively under the same conditions as in the separations of the anion mixture. By the conditions obtained in the separations of the standard mixture, Fe(III) and all of the subsidiary anions in steel are quantitatively separated.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2005.11a
• /
• pp.133-147
• /
• 2005

In order to investigate applicability for 2,2,2-trifluoroethyl methacrylate (TFEMA) produced by esterification of 2,2,2-trifluoroethanol(TFEA) and methacrylic acid(MA) using pervaporation membrane, poly(vinyl alcohol) (PVA) composite membranes were prepared with glutaraldehyde(GA) onto porous polyethersulfone(PES) support. The degree of crosslinking and thickness of PVA coating layer were analyzed by swelling test and SEM(scanning electron microscopy), respectively. Pervaporation test was done with two feed mixures; TFEA/water, MA/water. The pervaporation data were obtained as a function of content of crosslinking agent, feed composition, and operating temperature, respectively. In case of TFEA-water(90/10 wt%) feed mixture at $80^{\circ}C$, the optimized membrane showed the high permeation flux of 1.5 $kg/m^2hr$ and separation factor of 320. In case of MA-water(90/10 wt%) feed mixture, the membranealso showed high permeation flux of 2.3 $kg/m^2hr$ and separation factor of 740 in same conditions.

• Membrane and Water Treatment
• /
• v.8 no.5
• /
• pp.483-498
• /
• 2017

Novel mixed matrix membranes of Sodium Alginate (NaAlg) were developed by the incorporation ofunmodified, modified Phosphomolybdic acid (PMA) then cross-linked with glutaraldehyde externally. These membranes were prepared by the solution casting technique. Pervaporation (PV) experiments have been performed with pure NaAlg, unmodified NaAlg-PMA5, NaAlg-PMA10, modified NaAlg-mPMA5, and NaAlg-mPMA10 (wt. % of PMA 5 and 10) at 30, 40 and $50^{\circ}C$, to separate water-isopropanol feed mixtures containing 10-30 wt. % of water. Pervaporation results of NaAlg-mPMA10 produced a highest separation factor of 9028 with a flux of $0.269kg/m^2.h$ for 10 wt. % of water containing feed mixture. Both separation factor and flux for water increased significantly with increasing content of mPMA into NaAlg; a significant improvement in PV performance was observed for NaAlg-mPMA5 and NaAlg-mPMA10 membranes when compared to pure NaAlg& PMA-5, PMA-10 membrane.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1998.04a
• /
• pp.89-92
• /
• 1998

1. Introduction : Among many azeotropic compounds, pyridine which forms an azeotropic mixture with three moles of water boiling at 92-93$\circ$C is very useful synthetic intermediate in laboratory and industry. With conventional separation method, the dehydration of pyridine aqueous solution is difficult and requires strong drying chemicals. To overcome these difficulties, several researchers have investigated on the separation of pyridine from aqueous solution through polymer membranes. Kujawski reported several ion-exchang membranes containing carboxylic and sulfonic fuctional group for dehydration of aqueous pyridine solution [1]. We have applied the idea of activation of water tranport through ion-dipole interactions between polymer membrane and aclueous feed. Our previous studies reported on the in-situ complex membrane to separate water from aqueous pyridine solution based on simple acid'-base theory [2, 3]. Water transport was enhanced through in-situ complex formation between the , acid moiety in the membrane and the incoming pyridine moiety in the feed.

• YAKHAK HOEJI
• /
• v.10 no.4
• /
• pp.1-6
• /
• 1966

Various thiocyanatoammine chromium complex salts are prepared by the known methods and the Rf. value of these complex salts are determined by four developers. These four developers were used in the paper chromatographical work of cobalt complex salts by Yamamoto in 1954. It was also found that the developer A (Ch$_{3}$OH, acetone, NH$_{4}$OH) gave best results of these four developers and the decending development gave better results than ascending development in this experiment. In the case of decending development using developer A, it is found that the Rf. value is increased with the number of thiocyanate radical. The reason of this curious results can be explained that the thiocyanate radical in the complex ion is more active for the organic solvent than ammine radical. Shifting of electrons to the central metal and the charge of the complex ion can also effect ot the Rf. value but much questions are remained for the explanation of the above curious phenomenon. Separation of mixed sample is also studied for various mixture of the above complex salts. In the case of the mixture of hexammine and diammine complex salt, the clear separation is possible but in almost all other mixed sample, the results are not clear. Therefore it can be said that the results of this work can be used in the qualitative analysis of the individual complex salts, except the mixed sample of hexammine and diammine complex salts.