• Journal of Powder Materials
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• v.15 no.5
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• pp.371-377
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• 2008

This paper deals with the phase analysis of $MgB_2$ bulk using spark plasma sintering process after ball milling. Mg and amorphous B powders were used as raw materials, and milled by planetary-mill for 9 hours at argon atmosphere. In order to confirm formation of $MgB_2$ phase, DTA and XRD were used. The milled powders were fabricated to $MgB_2$ bulk at the various temperatures by Spark Plasma Sintering. The fabricated $MgB_2$ bulk was evaluated with XRD, EDS, FE-SEM and PPMS. In the DTA result, reaction on formation of $MgB_2$ phase started at $340^{\circ}C$. This means that ball milling process improves reactivity on formation of $MgB_2$ phase. The $MgB_2$ MgO and FeB phases were characterized from XRD result. MgO and FeB were undesirable phases which affect formation of $MgB_2$ phase, and it's distribution could be confirmed from EDS mapping result. Spark Plasma Sintered sample for 5 min at $700^{\circ}C$ was relatively densified and it's density and transition temperature showing super conducting property were $1.87\;g/cm^3$ and 21K.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2616-2622
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• 2013

A novel zwitterionic monomer 3-[(2-acrylamido)dimethylammonio]propanesulfonate (DMADAS) was designed and synthesized in this study. Then it was polymerized with acrylamide (AM) by free radical polymerization in 0.5 mol/L NaCl solution with ammonium persulfate ($(NH_4)_2S_2O_8$) and sodium sulfate ($NaHSO_3$) as initiator. The structure and composition of DMADAS and acrylamide-3-[(2-acrylamido)-dimethylammonio]propanesulfonate copolymer (P-AM-DMADAS) were characterized by FT-IR spectroscopy, $^1H$ NMR and elemental analyses. Isoelectric point (IEP) of P-AM-DMADAS was tested by nanoparticle size and potential analyzer. Solution properties of copolymer were studied by reduced viscosity. Antipolyelectrolyte behavior was observed and was found to be enhanced with increasing DMADAS content in copolymer. The results showed that the viscosity of P-AM-DMADAS is 5.472 dl/g in pure water. Electrolyte was added, which weakened the mutual attraction between sulfonic acid group and quaternary ammonium group. The conformation became loose, which led to the increase of reduced viscosity. The ability of monovalent and divalent cation influencing the viscosity of zwitterionic copolymer obeyed the following sequence: $Li^+$ < $Na^+$ < $K^+$, $Mg^{2+}$ < $Ca^{2+}$ < $Ba^{2+}$, and that of anion is in the order: $Cl^-$ < $Br^-$ < $I^-$, $CO{_3}^{2-}$ > $SO{_3}^{2-}{\approx}SO{_4}^{2-}$.

• Journal of IKEEE
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• v.3 no.1 s.4
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• pp.133-140
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• 1999

When the current optical communication system is used for the DWDM, it raise the serious interference because an interval between the adjacent channels is narrow. The FBG filter for the DWDM is able to reduce the interferences between the adjacent channels. In this paper, therefore, we find the reflection spectrums for the three types of induced index changes, that is, uniform, Gaussian apodized, and raised-cosine apodized. From the obtained results in this paper, we can see that uniform FBG does not fit, and that the smaller the maximum induced index change ${\sigma}$ is and the larger the value of parameter C in the raised-cosine apodized FBG and G in the Gaussian apodized FBG are, the fitter they are on the narrow filter for DWDM. But, we can also see that the raised-cosine apodized FBG has more excellent property than the Gaussian apodized FBG because it has the narrower maximum reflection spectrum band and the lower sidelobes than the other.

• Journal of Arbitration Studies
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• v.17 no.1
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• pp.57-75
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• 2007

Ever since franchising emerged in the industry of distribution, it has been growing explosively in the U.S.A. and all other countries as well. It is a method of expanding a business by licensing independent businessman to sell the franchiser's products and/or services or to follow a format and trade style created by the franchiser using the franchiser's trade marks and trade names. Franchising is a form of business that touches upon many different areas of law including, but not limited to, general contract law, general principles of commercial law, law of intellectual property, competition law, fair trade practices law and other industry specific laws e.g., the Fair Practices in Franchising Act in Korea. Arbitration is a long established, legally recognized procedure for submitting disputes to an outside person(s), mutually selected by the parties, for a final and binding decision. Despite its merits as an alternative dispute resolution, it has been criticized, on the other hand, particularly by franchisees' attorneys on the ground that even though it is required to protect the franchisees against the enforcement of pre-dispute arbitration agreements because of the franchisees' paucity of bargaining power vis-a-vis the franchiser, arbitration cannot afford it. Until recently, however, little has been written about the legal issues pertaining to franchise agreement and arbitration clause contained therein in Korea. This treatise reviews the cases and arguments in relation to the subject especially of the U.S.A., which have been accumulated for decades. The issues addressed herein are the pre-emption by the FAA, the disputes to be arbitrated, the selection and qualification of arbitrators, the place of arbitration hearings and the evidentiary rules applicable, the expenses of arbitration, theory of fiduciary duty and the like, all of which are relevant to franchise agreement.

• KSBB Journal
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• v.13 no.5
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• pp.554-560
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• 1998

Biopolymer from alkaline-tolerant Bacillus so. was purified, and its physico-chemical and structural properties were investigated. Crude biopolymer, precipitated by acetone from culture broth was fractionated into two fractions by gel chromatography on Sephadex G-200. Among two fractions, one fraction(PS I), which an acidic biopolymer precipitated by the CPC(cetylpyridinium chloride) treatment was studied further. PS I fraction had carboxyl groups and was positive at color reaction of sugar. PS I fraction also showed UV absorbance at 190-225nm. The purified acidic biopolymer was composed of 4% glucose, 8% glucosamine and 88% glutamic acid. Sugar components of the purified acidic biopolymer seemed to be linked to PGA(polyglutamic acid) which existed in the from of ${\gamma}$-peptide bond. By the results of Smith degradation of sugar components, glucose and glucosamine was bound by 1,3 glocosidic linkage. Therefore, this biopolymer was a glycopeptide, oligosaccaride ${\gamma}$-PGA. We concluded that the equivalent weight and the molecular weight of this biopolymer were estimated as about 171 and 5x105 dalton, respectively.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.8
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• pp.958-968
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• 2003

The purpose of this study was to clarify the different mechanical properties of fabrics among the theme groups classified by fashion fabric trend. This study can be useful for fabric marketers and planners to design new products. In order to carry out this study, the fabric samples of representative theme for‘2002/03 F/W fashion fabric trend were collected from a fashion company and were measured to analyze the mechanical properties, hand value(H.V) and total hand value(T.H.V) by KES-FB System. The results were as follows. 1. The theme-A of‘Luxury, Elegance’was consisted of wool, rayon and PET and had a lower B, 2HB of bending properties and a lower G and 2HG5 of shear properties. The theme-B of‘Technical, Functional’was consisted of synthetic fibers such as PET, PA, PU and elastic fiber and had a higher MIU and a lower MMD, SMD of surface properties. The theme-C of‘Vintage, Aged’was consisted of mostly cotton and had the highest B and 2HB. The theme-D of‘Fancy, Airy’was consisted of mostly woolen wool, polyacryl and polyamide and had a high MMD and SMD of surface properties and a high LC and RC of compression properties. 2. As the results of analyzing H.V and T.H.V through KES-FB system, the theme-A showed a higher Smoothness and lower Stiffness. The theme-B had a lower Smoothness, Fullness, Soft feeling and T.H.V and the theme-C had the highest Stiffness. The theme-D showed the highest Fullness and Soft Feeling but the lowest Stiffness.

• Journal of Environmental Health Sciences
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• v.35 no.5
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• pp.393-401
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• 2009

We isolated and identified a microorganism which was excellent for ammonia oxidation in the biological control of ammonia gas in odor producing materials from organic composting. The isolated strain was tested for growth characteristics and ammonia elimination efficiency under various conditions of temperature, pH, carbon concentration and ammonia concentration. The strain was isolated from a culture broth used in a $NO_2$ producing test with Griess-Ilosvay reagent. The results of 16S rRNA sequence from the isolated strain by using BLANST (Basic Local Alignment Search Tool) and confirming RDP (Ribosomal Database Project II) and ERRD (The European Ribosomal RNA Database) indicate that the strain is related to Delftia sp. UV-Spectrophotometer (Shimadzu, UVmini-1240) was used as a microbial growth test by measuring turbidity on OD660nm and ammonia concentration was measured by Spectrophotometer (HACH, DR-4000). The optimum growth culture conditions of the ammonia oxidizer Delftia sp. were $30^{\circ}C$, pH 7, glucose concentration 1.00% and $(NH_4)_2SO_4$ 0.5 g/l. Ammonia elimination efficiency was over 94% under the same conditions.

• Journal of Mechanical Science and Technology
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• v.14 no.3
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• pp.320-330
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• 2000

It is desirable to perform nondestructive evaluation (NDE) to assess material properties and part homogeneity because the manufacturing of carbon/carbon brake disks requires complicated and costly processes. In this work several ultrasonic techniques were applied to carbon/carbon brake disks (322mm ad, 135mm id) for the evaluation of spatial variations in material properties that are attributable to the manufacturing process. In a large carbon/carbon disk manufactured by chemical vapor infiltration (CYI) method, the spatial variation of ultrasonic velocity was measured and found to be consistent with the densification behavior in CYI process. Low frequency (e.g., 1-5MHz) through-transmission scans based on both amplitude and time-of-flight of the ultrasonic pulse were used for mapping out the material property inhomogeneity. Images based on both the amplitude and the time-of-flight of the transmitted ultrasonic pulse showed significant variation in the radial direction. The radial variations in ultrasonic velocity and attenuation were attributed to a density variation caused by the more efficient densification of pitch impregnation near the id and od and by the less efficient densification away from the exposed edged of the disk. Ultrasonic velocities in the edges of the disk. Ultrasonic velocities in the thickness direction were also measured as a function of location using dry-coupling transducers ; the results were consistent with the densification behavior. However, velocities in the in-plane directions (circumferential and radial) seemed to be affected more by the relative contents of fabric and chopped fiber, and less by the void content.

• Applied Biological Chemistry
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• v.48 no.4
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• pp.311-314
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• 2005

Approximately twelve hundred strains of Actonomycetes isolated from domestic soli were tested for their ability to produce extracellular phytase. Of all these isolates a strain, YB-26, that had the highest potential for phytase activity was chosen. The nucleotide sequence of 16S rDNA of the isolate YB-26 showed the highest similarity to that of strains beloning to genus Streptomyces. The partially purified extracellular phytase was obtained from the culture filtrate of Streptomyces sp. YB-26 grown on GSM broth by ammonium sulfate precipitation (15-70%), DEAE-Sepharose column and Q-Sepharose column chromatography. The partially purified enzyme showed the maximum activity for hydrolysis of phyate at $60^{\circ}C$ and pH 7.0, and retained 90% of its maximum activity at the range of pH $6.0{\sim}8.0$. It was thermolabile and its thermostability did not increase in the presence of calcium chloride.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.397-400
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• 1995

Effects of rheological parameters, such as shear rate, temperature, concerntration, salts on the apparent viscosity of chitosan(deacetylation degree: $84\%$, Mw: 267,000) dissolved in acetate buffer(pH 4.5) were investigated. Rheologiral properties of chitosan solution from cuticle of red snow crab (Chinonecetes japonicus) are as follows. $0.5\%$ chitosan in 0.1M acetate buffer (pH 4.5) solution showed Bingham flow having hysteresis loop. It's flow equation was $\sigma=0.757+19.6_\gamma(r^2=0.99)$. The viscosity of chitosan solution is exponentially increased with its concentration, and showed Arrhenius dependence with respect to the temperature $(10^{\circ}C-40^{\circ}C).$ When various salts were added to chitosan solution, the viscosity decreased as the concentration of counterion increased. But the type ot counterions itself does not have any significant effects on the viscosity.