• Korean Journal of Materials Research
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• v.26 no.6
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• pp.306-310
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• 2016

To produce 4N grade high-purity silica powder from natural ore, the mineralogical characteristics of natural silica ore were investigated and their effects on the purification process were revealed. The Chinese silica mineral ore used was composed of iron and aluminum as main impurities and calcium, magnesium, potassium, sodium, and titanium as trace impurities; these trace impurities generally exist as either single oxides or complex oxides. It was confirmed that liberation and acidic washing of the impurities were highly dependent on the particle size of the ground silica ore and on its mineralogical characteristics such as the distribution and phases of existing impurities. It is suggested that appropriate size reduction of silica ore should be realized for optimized purification according to the origin of the natural silica ore. A single step purification process, the mechano-chemical washing (MCW) process, was proposed and verified in comparison with the conventional multi step washing process.

• Analytical Science and Technology
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• v.15 no.1
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• pp.87-90
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• 2002

The content of $SiHCl_3$ as a trace impurity in $SiCl_4$ was analyzed by Near IR spectrophotometer with optical fiber. The strong absorption bands of $5345{\sim}5116cm^{-1}$ and $4848{\sim}4349cm^{-1}$ were used for analysis of $SiHCl_3$, and the detection limit of impurity $SiCl_3$ was appeared to be 0.005 ％ in the spectrum. The quantitative analysis by Near IR spectrophotometry showed the analytical possibility of trace impurity in $SiCl_4$ without sample pre-treatment not only in the laboratory but also in the field.

• Journal of computational fluids engineering
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• v.16 no.4
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• pp.110-115
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• 2011

A modern optical fiber manufacturing process requires the sufficient cooling of glass fibers freshly drawn from the heated and softened silica preform in the furnace, since the inadequately cooled glass fibers are known to cause improper polymer resin coating on the fiber surface and to adversely affect the product quality of optical fibers. In order to greatly enhance the fiber cooling effectiveness at increasingly high fiber drawing speed, it is necessary to use a dedicated glass fiber cooling unit with helium gas injection between glass fiber drawing and coating processes. The present numerical study features a series of three-dimensional flow and heat transfer computations on the cooling gas and the fast moving glass fiber to analyze the cooling performance of glass fiber cooling unit, in which the helium is supplied through the discretely located rectangular injection holes. The air entrainment into the cooling unit at the fiber inlet is also included in the computational model and it is found to be critical in determining the helium purity in the cooling gas and the cooling effectiveness on glass fiber. The effects of fiber drawing speed and helium injection rate on the helium purity decrease by air entrainment and the glass fiber cooling are also investigated and discussed.

• Analytical Science and Technology
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• v.13 no.2
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• pp.158-165
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• 2000

The purity of gypsum and quantitation of impurities of flue gas gypsum will not only play an important role in deciding of the optimal condition during a trial run of FGD (flue gas desulfurization), but also can be utilized in quality control of gypsum. The purity of gypsum can be determined from combined water, sulfur trioxide and calcium concentration. We found that the thermal analysis by TGA (thermogravimetric analysis) was the most accurate and convenient method to determine the purity of gypsum. This method will be done in a hour and the results were reproducible. On the other hand, the best way of the analysis of impurities in gypsum was fusion method using $LiBO_2$ as a fusion agent. We also determined the amount of $CO_2$ gas to analyze magnesium carbonate and calcium carbonate contents. The analyses of combined water by TGA, fusion method followed by ICP-AES (inductively coupled plasmaatomic emission spectroscopy) and determination of $CO_2$ amount can lead to more accurate and convenient method for gypsum analysis.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.4
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• pp.217-224
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• 2010

The purity methods to determine LOD/LOQ using standard deviation of the residual, intercept and blank by IUPAC and ACS describe many of the pitfalls and pose significant challenges to analytical chemists. Therefore, the aim of this study is the development of the simple, easy, convenient and statistically significant method to determine LOD in quantitative analysis of organic solvents by GC. The new approaching method by linearization in the given concentration range used coefficient of variation ; ${\sigma}_{n-1}$/S(standard deviation, ${\sigma}_{n-1}$ and average, S) of sensitivity(Response/concentration). The comparison of results among the purity methods(IUPAC and ACS) and the linearization have been fulfilled the F-test for standard deviations and t-test for LOD range values. The results of F-test and t-test are satisfied within 95 % confidence level, respectably. The LOD values determined by the new procedure are n-Hexane 0.0116 mg/$m^3$, Toluene 0.0807 mg/$m^3$, and o-Xylene 0.0494 mg/$m^3$. Because the standard deviation of the residual, intercept and blank and the slope of calibration curve are not calculated and the new approaching method use the coefficient of variation of sensitivity by linearization, this new method is simple, easy, convenient and statistically significant. In future, many chemical analysts will expect to applicate and routinely use this method in the all quantitative analysis.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.525-534
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• 2014

Microsatellite markers were used to identify 58 major commercial melon cultivars, and to assess hybrid seed purity of a melon breeding line known as '10H08'. A set of 412 microsatellite primer pairs were utilized for fingerprinting of the melon cultivars. Twenty-nine markers showed hyper-variability and could discriminate all cultivars on the basis of marker genotypes, representing the genetic variation within varietal groups. Cluster analysis based on Jaccard's distance coefficients using the UPGMA algorithm categorized 2 major groups, which were in accordance to morphological traits. The DNA bulks of female and male parents of breeding line '10H08' were tested with 29 primer pairs based on microsatellites to investigate purity testing of $F_1$ hybrid seeds, and 5 primer pairs exhibited polymorphism. One microsatellite primer pair (CMGAN12) produced unambiguous polymorphic bands among the parents. Among 192 seeds tested with CMGAN12, progeny possibly generated by self-pollination of the female parent were clearly distinguished from the hybrid progeny. These markers will be useful for fingerprinting melon cultivars and can help private seed companies to improve melon seed purity.

• KSBB Journal
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• v.23 no.1
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• pp.37-43
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• 2008

The use of antihemophilic factor IX complex has been associated with a variety of thrombotic complications, the major cause of which was the contamination of thrombogenic proteins such as vitamin K-dependent clotting factors II, VII, and X. In order to produce a commercial factor IX (GreenNine VF) free from thrombogenic potential, industrial-scale production process for high-purity factor IX from human plasma has been developed. The purification process contains cryo-precipitation, DEAE-sephadex A-50 anion-exchange chromatography, DEAE-toyopearl 650M anion-exchange column chromatography, heparin-sepharose 6FF affinity column chromatography, and CM-sepharose FF cation-exchange column chromatography. Also the process includes two viral inactivation and removal procedures, solvent/detergent treatment and nanofiltration using Viresolve NFP filter. The purification yield was 35.4%. The specific activity in the purified concentrate was 190.8 IU/mg which exceeded that in the factor IX complex (FacNine) by a factor of 48. The activities of factor II, VII, and X were not detected in GreenNine VF. SDS-PAGE analysis showed that GreenNine VF had the highest purity in comparison with commercially available high purity factor IX concentrates, Mononine, Octanyne, Berinin HS, and Immunine STIM plus 600. One batch size of the production was 2,400 vials of 250 IU product or 1,200 vials of 500 IU product from 1,600 L cryo-poor plasma.

• The Korean Journal of Nuclear Medicine
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• v.23 no.1
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• pp.71-83
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• 1989

For the development of $^{99m}Tc-labelled$ antimony sulfide colloid and hydroxyethyl starch, various experiments such as preparation of colloid, control of the distribution of particle size, establishment of labelling conditions, determination of labelling yield and radiochemical purity, examination of stability, and organ imagings of rabbits etc. were carried out. 1) Antimony sulfide colloid was readily prepared by the reaction of aqueous solution of antimony potassium tartrate with hydrogen sulfide generated by treating ferrous sulfide with dilute sulfuric acid. The colloid could be stabilized by adding small amount of polyvinylpyrrolidone. 2) Electron microscopy analysis exhibited the distribution of colloid size in the range of $1\sim15nm$ with a major portion of 9 m. The colloid solution was sterilized by membrane filtration $(0.2{\mu}m)$ and then stored at $4^{\circ}C$. This sterilized colloid was so stable that it was usable at least for one year. 3) The antimony sulfide colloid was labelled by adding sodium $pertechnetate-^{99m}Tc$ solution to the reaction vial, followed by adding hydrochloric acid and then boiled for 30 min. The optimal pH of the reaction mixture was found to be in the range of $1.3\sim1.4$. Instant thin layer chromatography (ITLC) analysis showed high labelling yield of above 99.5%. This labelled colloid maintained high radio-chemical purity of above 99% until 10 hours after labelling. 4) Animal studies showed high uptake of $^{99m}Tc-Sb_2S_3$ colloid at lymph vessels and nodes indicating a suitable agent for lymphoscintigraphy. Satisfactory results were also abtained in other clinical studies. 5) Hydroxyethyl starch (HES $0.6\sim1.0%$) was labelled with $Na^{99m}TcO_4$ in the presence of $SnCl_2$ with high labelling yield of above 99.5%. The optimal pH of the reaction mixture was in the range of $1.8\sim2.0$. $^{99m}Tc-HES$ maintained high radiochemical purity of above 99% until 10 hours after labelling. 6) Animal studies showed that $^{99m}Tc-HES$ migrated more rapidly from the injection sites into the lymph vessels than $^{99m}Tc-Sb_2S_3$ colloid while less amount of the former was uptaken at lymph nodes than that of the latter. Similar phenomenon was also observed in other clinical studies. As a result, $^{99m}Tc-Sb_2S_3$ colloid was found to be more effective lymphoscintigraphic agent than $^{99m}Tc-HES$.

• Journal of Industrial Technology
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• v.4
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• pp.55-60
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• 1984

Silicastone of Hongcheon in Kangweon province was characterized by means of chemical analysis, scanning electron microscope, polarization microscope and x-ray diffractometer. The results showed that the purity of $SiO_2$ is over 97.64 in Wt-%. It also contains 0.046-0.417 Wt-% $Fe_2O_3$ and some others as impurity. The impuity exist as a isolated mineral type of hematite, sericite, apatite etc.

• Applied Biological Chemistry
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• v.1
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• pp.26-33
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• 1960

Organic mercurial fungicides, for seed treatments and dust formulations, has been increasingly used by farmers. Evaluation of the purity of organic mercurial fungicides has been performed by precipitation method at this laboratory. There are several methods for the an alyses of organic mercuric formulation, among which are (1) Precipitation met hod, (2) Volatilization method, (3) Volumetric method, and (4) Dithizon method. These methods, however, show some deffects in specificity (differentiation of organic form) and quantitativity. Polarography applied for the estimation of phenyl mercuric acetate was found to be simple, rapid and accurate. Tile fundamental method of polarography arid accuracy of analysis are discussed statistically and a satisfactory results was obtained.