• Korean Journal of Soil Science and Fertilizer
• /
• v.7 no.3
• /
• pp.155-161
• /
• 1974

In order to investigate the effect of split application of silicate fertilizers on the rice plant, this studies, designed with two kinds of silicate material, wollastonite and high concentrated fused silicate material, and 4 types of application dates on the pot experiment without chemical control against diseases, have conducted the silica analysis of rice plant and diseased rates of plant during the all growing stages. The silica contents in rice plant with basal application were increased most highly compared with the split applications during the all growing stage, but they were all much the same between the basal and split application at the harvest. High concentrated fused silicate material was more useful to increase the silica content in rice plant than wollastonite and effect of split application of silica was dominant with this fused silicate material. The diseased leaf area by rice blast was decreased from the 50% of uncontrolled plot to 20~40% by the split application with wollastonite and to 5~15% with high concentrated fused silicate material. Also percents of deseased panicles were decreased to 20% with wollastonite and to 10% with high concentrated fused silicate material.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.14
• /
• pp.71-77
• /
• 1973

To observe the effect of fused phosphate fertilization, as a soil improvement material, in low productive paddy field which has rapid permeable sandy-skeletal texture, this experiment was carried out under five different levels of fused phosphate. The results obtained are briefly as follows: 1. Rice, grown in areas receiving annual fused phosphate application of from 200 to 250kg per 10a showed yield increases of about 10 to 27 percent based on 1, 000 grain weight of brown rice. Other favorable effects from high fused phosphate applications include increased number of panicles, faster ripening rate of the rice, and lower infection rate of blast. 2. In the soil analysis after the experiment, the useful soil chemical properties, such as available phosphate, silica, soil pH, exchangeable calcium, magnesium, and base saturation were increased significantly. The exchangeable potassium, however, was not changed noticeably. 3. The relation between the major soil chemical properties, especially available phophate and silica, and yield component which directly effect yields, showed a significant correlation statistically.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.705-710
• /
• 2001

So for the quartz-glassy crucible wastes which was used for pulling up silicon-single-crystal ingot have simply reused for refractory raw-materials, or exhausted. This study is concerned on the advanced recycling-technology that is obtained by the proper micro-particle preparation process in order to fabricate fine amorphous silica filler for EMC (Epoxy Molding Compound). Therefore, this paper will deal with the physical, chemical and thermal pre-treatment process for efficient impurity removal and with the proper micro-particle process for producing the amorphous silicafiller. In view of the results, if the chemical, physical and thermal pre-treatment process for efficient elimination of impurity was passed, the purity of wasted fused glassy crucible is almost equal to the its of first anhydrous quartz glass. Thus, it was understood that this wasted fused glassy crucible was sufficient value of recycling, though it was damaged. When the ingot was fabricated, Phase transformation of crystallization by heat treatment (heat hysteresis phenomenon) was not changed. So, it was understood that as fused silica in the amorphous state, as It is, recycling possibility was very high

• Bulletin of the Korean Chemical Society
• /
• v.27 no.9
• /
• pp.1429-1432
• /
• 2006

Polyaromatic hydrocarbons were separated by a capillary supercritical fluid chromatographic (SFC) column and detected by a UV detector at the wavelength of 280 $\mu$m. The temperature-controlled restrictor was designed for UV detection. The temperature-controlled restrictor is a 20 cm length of deactivated fused silica of 7 mm i.d. which is held right after UV detector of the capillary SFC. The temperature of the restrictor will control the flow rate of the supercritical carbon dioxide mobile phase through the capillary column in SFC. Thus as the pressure in the column is increased from 1500 psi to 4000 psi during a pressure program, the temperature of 7 $\mu$m fused-silica tube can be varied from 100 to 350 ${^{\circ}C}$ to maintain a constant flow rate.

• BMB Reports
• /
• v.31 no.4
• /
• pp.384-390
• /
• 1998

DNA fragments (51-587 bp) were separated by capillary electrophoresis using entangled polymer, hydroxyethylcellulose, in uncoated fused silica capillary columns. The factors affecting the separation of DNA fragments with hydroxyethylcellulose media were evaluated, i.e., the concentration of buffer and entangled polymer, effects of additives (methanol, ethidium bromide, EDTA), temperature, and injection methods. Maximum performance was obtained by adding 5% methanol in 0.5% hydroxyethylcellulose solution at $30^{\circ}C$. Addition of methanol in polymer media increased the resolution of small size DNA fragments (< 100 bp). On the other hand, addition of ethidium bromide and EDTA, which are commonly used in conventional DNA separation, reduced the resolution of DNA fragments in the polymer solution. It turns out that the separation behavior of DNA in entangled polymer is more sensitive to the running condition compared to that in polyacrylamide gel-filled capillary, but the reproducibility of DNA separation in entangled polymer is reliable.

• Transactions of Materials Processing
• /
• v.21 no.2
• /
• pp.138-143
• /
• 2012

A polishing method using magnetorheological (MR) fluid has been developed as a new precision technique to obtain a fine surface. The process uses a MR fluid that consists of magnetic carbonyl iron (CI) particles, nonmagnetic polishing abrasives, water and stabilizers. But the CI particles in MR fluids cause a severe corrosion problem. When coated with Xanthan gum, the CI particles showed long-term stability in corrosive aqueous environment. The surface roughness obtained from the MR polishing process was evaluated. A series of experiments were performed on fused silica glass using prepared slurries and various process conditions, including different polishing times. Outstanding surface roughness of Ra=2.27nm was obtained on the fused silica glass. The present polishing method could be used to produce ultra-precision micro parts.

• Journal of the Korean Chemical Society
• /
• v.45 no.2
• /
• pp.143-148
• /
• 2001

In this study, open tubular capillary columns for ion charomatography were developed to analyze trace amount of ions in samples. When small I,D. capillary column length is 1.0~5.0 m. The capillary columns were made using fused silica capillary(I.D:50㎛) and DMEOHA latex particles. The new conductivity cell and suppressor were also developed and made for capillary column ion chromatography. When several anions(fluoride, nitrite, nitale,chlorate,phosphte, sulfate) were analyzed using these capillary columns. reproducible and good chromatograms were obtained.

• Journal of Korea Foundry Society
• /
• v.31 no.5
• /
• pp.267-273
• /
• 2011

Erosion and thermal shock resistance of several refractory materials have been investigated, which are expected to be used as nozzles in a planar flow casting equipment for amorphous alloys. The test was conducted on five materials; graphite, boron nitride, fused silica, alumina and zirconia. Test specimens were preheated and dipped into the melt of carbon steel and amorphous alloys. Some test specimens were rotated to develop high erosion and to shorten the test periods. Fused silica and boron nitride specimens showed the excellent erosion and thermal shock resistance irrespective of the kind of melt and melting atmosphere.

• Journal of the Korean Ceramic Society
• /
• v.35 no.9
• /
• pp.923-932
• /
• 1998

Al2O3/Al composites were produced by displacement reaction method which was carried out by imm-ersing the sintered silica preform which was prepared form fused silica powder in molten aluminu. an ac-tivation energy of 94kJ/mole was calculated from Al-SiO2 reaction data in 1000-130$0^{\circ}C$ temperature range With increase of reaction temperature the alumina particle in the Al2O3/Al composites produced with pur metal Al showed grain growth and the growth of alumina particle in Al2O3/Al composite produced by using of Mg contained Al alloy was inhibited. The flexural strength of Al2O3/Al composites produced at 100$0^{\circ}C$ showed the highest value as 393 MPa. Flexural strength of the composite fabricated at 85$0^{\circ}C$ showed higher deviation than that of the composite produced at above 100$0^{\circ}C$ Low flexural strength of the composite fa-bricated at 120$0^{\circ}C$ due to the growth of pore and alumina particle size. The hardness of composites de-pended on alumina content in Al2O3/Al composite decreased with increasing of aluminium content in case the same alumina content and increased with increasing of silicon content in composite.

• Journal of the Korean Ceramic Society
• /
• v.53 no.2
• /
• pp.246-252
• /
• 2016

Complex designed silica-based ceramic cores were fabricated by ceramic injection molding. Slow heating rate (0.2K/min) for debinding restrained bloating on the surface of ceramic cores. To investigate effect of sintering conditions on mechanical properties of ceramic cores, green bodies were sintered at temperatures in a range from $1150^{\circ}C$ to $1400^{\circ}C$ for various dwelling times (6 h to 48 h). Sintering above $1300^{\circ}C$ for 12 h and dwelling time over 24 h at $1200^{\circ}C$ reduce the flexural strength and increase the linear shrinkage of ceramic cores. Cristobalite, formed by high sintering temperature or long dwelling time, induces reduction of mechanical properties due to its phase transformation, which is accompanied by volume contraction and microcracking. Ceramic core sintered at $1200^{\circ}C$ for 12 h endured wax patterning and shell molding, and was manufactured successfully.