• Korean Journal of Mineralogy and Petrology
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• v.33 no.1
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• pp.29-39
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• 2020

A series of struvite (MgNH₄PO₄·6H₂O) was synthesized and dried at various temperatures (15-60℃). Crystallization of struvite and its structural properties were significantly influenced by synthetic and drying temperature. Struvite was favorably formed at synthetic temperatures ≤30℃ with an inverse relationship between the crystallinity and synthetic temperature. The crystallinity of struvite was also significantly reduced by an increase in drying temperature from 45℃ to 60℃ due to the loss of structural water molecules and ammonium ions by the facilitated thermal decomposition. However, struvite formed at lower synthetic temperature showed higher crystallinity, and its amorphization by thermal decomposition was inhibited. These results demonstrate that struvite formed at low temperature with an stable condition thermodynamically through favorable crystallization shows high crystallinity and stability with respect to the structural and thermal resistance.

• New & Renewable Energy
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• v.8 no.2
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• pp.24-32
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• 2012

Natural gas hydrates have a high potential as the 21st century new energy resource, because it have a large amount of deposits in many deep-water and permafrost regions of the world widely. Natural gas hydrate is formed by physical binding between water molecule and gas mainly composed of methane, which is captured in the cavities of water molecules under the specific temperature and pressure. $1m^3$ methane hydrate can be decomposed to the methane gas of $172m^3$ and water of $0.8m^3$ at standard condition. Therefore, there are a lot of practical applications such as separation processes, natural gas storage transportation and carbon dioxide sequestration. For the industrial utilization of methane hydrate, it is very important to rapidly manufacture hydrate. However, when methane hydrate is artificially formed, its reaction time may be too long and the gas consumption in water becomes relatively low, because the reaction rate between water and gas is low. So in this study, hydrate formation was experimented by adding natural zeolite and Synthetic zeolite 5A in distilled water, respectively. The results show that when the Synthetic zeolite 5A of 0.01 wt% was, the amount of gas consumed during the formation of methane hydrate was higher than that in the natural zeolite. Also, the natural zeolite and Synthetic zeolite 5A decreased the hydrate formation time to a greater extent than the distilled water at the same subcooling temperature.

• The Journal of the Korean dental association
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• v.13 no.12
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• pp.1098-1100
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• 1975

• Korean Journal of Materials Research
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• v.25 no.6
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• pp.265-268
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• 2015

ZnO micro/nanocrystals at large scale were synthesized through the thermal evaporation of Al-Zn mixtures under air atmosphere. The effect of synthetic temperature and time on the morphology of the micro/nanocrystals was examined. It was found that the temperature and time affected the morphology of the ZnO crystals. At temperatures below $900^{\circ}C$, no crystals were synthesized. At a temperature of $1000^{\circ}C$, ZnO crystals with a rod shape were synthesized. With an increase in temperature from $1000^{\circ}C$ to $1100^{\circ}C$, the morphology of the crystals changed from rod shape to wire and granular shapes. As the time increased from 2 h to 3 h at $1000^{\circ}C$, tetrapod-shaped ZnO crystals started to form. XRD patterns showed that the ZnO crystals had a hexagonal wurtzite structure. EDX analysis revealed that the ZnO crystals had high purity. It is believed that the ZnO nanowires were grown via a vapor-solid mechanism because no catalyst particles were observed at the tips of the micro/nanocrystals in the SEM images.

• Journal of Plant Biotechnology
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• v.48 no.4
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• pp.255-263
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• 2021

Paederia foetida L. is an important medicinal plant that has been used for the treatment of various gastrointestinal related ailments by different tribal communities in India. This plant is also known for its use as a food. Due to overexploitation, P. foetida has been classified as a vulnerable plant in some states of India. The propagation of P. foetida by conventional methods is easy but very slow. Synthetic seed technology offers incredible potential for in vitro propagation of threatened and commercially valuable plants, and can also facilitate the storage and exchange of axenic plant material between laboratories. However, synthetic seed production for P. foetida has not yet been reported. Thus, to the best of our knowledge, the present study is the first attempt to produce synthetic seeds of P. foetida by calcium alginate encapsulation of in vitro regenerated axenic nodal segments. Sodium alginate (3%) and CaCl₂ (100 mM) were found to be the optimal materials for the preparation of ideal synthetic seeds, both in terms of morphology and germination ability. The synthetic seeds showed the best germination (formation of both shoot as well as root; 83.3%) on ½ MS medium augmented with 0.5 mg/L indole-3-acetic acid. The plantlets obtained from these synthetic seeds could be successfully acclimatized under field conditions. We also studied the storage of these synthetic seeds at low temperature and their subsequent sprouting/germination. The seeds showed a germination rate of 63.3% even after 21 days of storage at 4 ℃; thus, they could be useful for transfer and exchange of P. foetida germplasm.

• Korean Journal of Veterinary Service
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• v.29 no.3
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• pp.317-330
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• 2006

This study was conducted to develop the analytical method about simultaneous determination for synthetic antimicrobials in muscle by high performance liquid chromatography - mass selective detector (HPLC- MSD). Solid phase extraction (SPE), matrix solid phase dispersion (MSPD) and liquid-liquid extraction (LLE) have been adapted as pretreatment procedures for HPLC- MSD. Among various solvent tested, methanol was chosen for extraction of synthetic antimicrobials in muscles. For the optimized response, the values of various MS parameters including fragment voltage, drying gas flow, nebulizer pressure, drying gas temperature were verified. The average recovery rates using MSPD and SPE for muscles of bovine and pork were 78.9-127.1% and 78.3-121.7%, respectively. This method was verified the satisfactory performance for fourteen synthetic antimicrobials excepting carbadox in muscle of pork as detection limit of $0.05{\mu}g/g$ on API/ES SIM mode.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1533-1538
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• 2003

The present technology of dielectric heating welding for synthetic resin sheet has a switching frequency over 10MHz by using vacuum tube elements, and has restrictively been applied to PVC whose dielectric loss is comparably high. The technology, however, has a difficulty in applying to materials which are made for environment and have low dielectric lose compared with other synthetic resin materials. Recently, the application of materials made for environment is increased so that the technology is faced with the limit. In this paper, a high frequency induction heating welder for synthetic resin sheet is designed applying temperature control by indirect heating to solve the problems about direct heating synthetic resin made for environment.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.3
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• pp.57-62
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• 2014

With synthesis temperature and adding amount of oleylamine, nanometer-sized Cu particles were fabricated by heptyl alcohol-based chemical synthesis. The synthetic temperature and amount of oleylamine changed excessively the shape and phase of synthesized nanoparticles. Only cubic-shaped $Cu_2O$ phase was formed at $160^{\circ}C$ regardless of the amount of oleylamine because of imperfect reduction reaction, representing results that the average size of $Cu_2O$ particles decreased with increasing the amount of oleylamine. In the case the synthesis at $170^{\circ}C$, however, nanoparticles of irregular sphere or peanut shapes were synthesized. Moreover, the average size of nanoparticles decreased continuously and gradually with an increase of the amount of oleylamine. According to the size decrease, the synthesized $Cu_2O$ nanoparticles were also transformed into pure Cu nanoparticles.

• KSBB Journal
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• v.14 no.2
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• pp.167-173
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• 1999

A new synthetic medium was developed for the submerged mycelial cultures of Phellinus linteus. The medium for maximum mycelial growth of Phellinus linteus (3 days incubation, 28$^{\circ}C$, pH 5) consisted of (per 1 L): glucose, 90 g peptone, 10 g soluble starch, 10 g yeast extract, 3 g KH2PO4, 1 g MgSO4.7H2O, 1 g and CaCl2, 0.1 g. The concentrations of glucose, peptone, yeast extract, KH2PO4, MgSO4.7H2O, and CaCl2 were examined in the ranges of 10~90 g/L, 0~10 g/L, 0~15 g/L, 0~2 g/L, 0~1 g/L, and 0~0.5 g/L, respectively. The dry weight of mycelium in 3 days increased to 16.79 mg/mL using the new synthetic medium. The optimum temperature for mycelial growth of Phellinus linteus was 28$^{\circ}C$. The concentrations of KH2OP4, CaCl2, and yeast extract, which gave the maximum mycelial growth of Phellinus linteus, existed in the concentration ranges examined in this study. But, in the cases of other compositions (MgSO4.7H2O, peptone, and glucose), the mycelial growth of Phellinus linteus increased with the concentration in the ranges.

• Computers and Concrete
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• v.13 no.3
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• pp.325-342
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• 2014

The use of lightweight aggregate (LWA) instead of ordinary aggregate may make lightweight aggregate concrete, which possesses many advantages such as lightweight, lower thermal conductivity, and better fire and seismic resistance. Recently the developments of LWA have been focused on using industrial wastes as raw materials to reduce the use of limited natural resources. In view of this, the intent of this study was to apply Taguchi optimization technique in determining process condition for producing synthetic LWA by incorporating waste thin film transition liquid crystal displays (TFT-LCD) glass powder with reservoir sediments. In the study the waste TFT-LCD glass cullet was used as an additive. It was incorporated with reservoir sediments to produce LWA. Taguchi method with an orthogonal array L16(45) and five controllable 4-level factors (i.e., cullet content, preheat temperature, preheat time, sintering temperature, and sintering time) was adopted. Then, in order to optimize the selected parameters, the analysis of variance method was used to explore the effects of the experimental factors on the performances (particle density, water absorption, bloating ratio, and loss of ignition) of the produced LWA. The results showed that it is possible to produce high performance LWA by incorporating waste TFT-LCD glass cullet with reservoir sediments. Moreover, Taguchi method is a promising approach for optimizing process condition of synthetic LWA using recycled glass cullet and reservoir sediments and it significantly reduces the number of tests.