• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.1
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• pp.11-17
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• 2007

The spherical NiZn ferrite particles were prepared by ultrasonic spray pyrolysis with mixed solution of aqueous metal nitrates. The NiZn ferrite particle was observed with nano-sized primary particles of about 10 nm or less before annealing which represented as paramagnetic behavior measured at 77 K and room temperature. The typical abnormal growth of primary particles like polyhedral primary particles was observed by annealing at 1273 K with Zn-concentration dependency. The XRD patterns showed good crystallinity of NiZn ferrite powder after annealing. In annealing process, the intra-particle sintering phenomenon was observed and the spherical particle morphology was collapsed at 1673 K. The saturation magnetization of NiZn ferrite powder for each annealing temperature was decreased with measuring temperature of $77{\sim}$300K.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.168-173
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• 2000

Flame aerosol synthesis technology refers to the formation of fine particles from gases in flame and is widely used in practical materials processing. In this paper, an experimental investigation was performed on growth of the silica particles that were generated in $H_2/O_2$ Diffusion Flame by the direct injection or TEOS using Electro-spraying method. in this flame aerosol synthesis, four main parameters or nos interaction (flame temperature, residence time or particle in flame, TEOS flow rate, applied voltage) for particle generation and growth was investigated along the axial direction above the burner. A fairly monodisperse non-aggregated particles were successfully obtained.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1172-1177
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• 2004

The evolution of incipient soot particles has been examined by high resolution electron microscopy (HRTEM) and elemental analyzer in ethylene-air inverse diffusion flames. Laser Induced Incandescence(LII) and laser scattering methods were introduced for examining the change of soot volume fraction and morphological properties in combustion generated soot qualitatively. Soot particles, collected by thermophoretic sampling were analyzed by using HRTEM to examine the nano structure of precursor particles. HRTEM micrographs apparently reveal a transformation of condensed phase of semitransparent tar-like material into precursor particles with relatively distinct boundary and crystalline which looks like regular layer structures. During this evolution histories C/H analysis was also performed to estimate the chemical evolution of precursor particles. The changes of C/H ratio of soot particles with respect to residence time can be divided into two parts: one is a very slowly increasing regime where tar-like materials are transformed into precursor particles (inception process) the other is an increasing region with constant rate where surface growth affects the increase of C/H ratio dominantly (surface growth region). These results provide a clear picture of a transition to mature soot from precursor materials.

• Journal of the Korean Society of Combustion
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• v.9 no.2
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• pp.38-44
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• 2004

The evolution of incipient soot particles has been examined by high resolution electron microscopy (HRTEM) and elemental analyzer in ethylene-air inverse diffusion flames. Laser Induced Incandescence(LII) and laser scattering methods were introduced for examining the soot volume fraction and morphological properties in combustion generated soot qualitatively. Soot particles, collected by thermophoretic sampling, were analyzed by using HRTEM to examine the nano structure of precursor particles. HRTEM micrographs apparently reveal a transformation of condensed phase of semitransparent tar-like material into precursor particles with relatively distinct boundary and crystalline which looks like regular layer structures. During this evolution histories, C/H analysis was also performed to estimate the chemical evolution of precursor particles. The changes of C/H ratio of soot particles with respect to residence time can be divided into two parts: one is a very slowly increasing regime where tar-like materials are transformed into precursor particles (inception process) the other is an increasing region with constant rate where surface growth affects the increase of C/H ratio dominantly (surface growth process). These results provide a clear picture of a transition to mature soot from precursor materials.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.299.1-299.1
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• 2003

Multivesicular DepoFoam technology is best suited for the encapsulation and sustained release of water-soluble drugs. The purpose of the present study was to prepare multivesicular DepoFoam particles and investigated possibility of oral delivery of a peptide, human epidermal growth factor (rhEGF). The multivesicular DepoFoam particles containing rhEGF was prepared by a two step water-in-oil-in-water double emulsification process. (omitted)

• Journal of Powder Materials
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• v.9 no.3
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• pp.189-198
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• 2002

In this work, transient liquid phase (TLP) bonding of Ni-Cr heat resisted cast alloy (HP) was investigated. And also the behaviors of the solid particles distributed in the interlayer during TLP bonding were investigated. The MBF-60 and solid particles (Ni, Fe, and $Al_2O_3$ powders respectively) added MBF-60 which will be a liquid phase coexisting with solid particles at the bonding temperature were used as insert metal. The effective and sound bonding was possible by spark plasma sinter-bonding due to the differences of electric resistance between base metal and liquid insert layer which creates high temperature region. During the isothermal solidification, $Al_2O_3$ particles and solid particles of liquid phase sintered insert metal have shown no growth, while Ni and Fe particles grow rapidly. In this TLP bonding using the MBF-60 and distributed Fe, Ni particles as insert materials, the whole isothermal solidification process was dominated by the growth rate of the solid particles distributed in the interlayer.

• Carbon letters
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• v.14 no.4
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• pp.228-233
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• 2013

In this work, we report in-situ observations of changes in catalyst morphology, and of growth termination of individual carbon nanotubes (CNTs), by complete loss of the catalyst particle attached to it. The observations strongly support the growth-termination mechanism of CNT forests or carpets by dynamic morphological evolution of catalyst particles induced by Ostwald ripening, and sub-surface diffusion. We show that in the tip-growth mode, as well as in the base-growth mode, the growth termination of CNT by dissolution of catalyst particles is plausible. This may allow the growth termination mechanism by evolution of catalyst morphology to be applicable to not only CNT forest growth, but also to other growth methods (for example, floating-catalyst chemical vapor deposition), which do not use any supporting layer or substrate beneath a catalyst layer.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.6
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• pp.295-300
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• 2010

Metathetic route for the $MWO_4$ (M=Zn, Co) particles is a simple method of synthesis and a viable alternative method in a short time. $MWO_4$ (M=Zn, Co) particles were synthesized using solid-state metathetic (SSM) method with microwave irradiation. The $MWO_4$ (M=Zn, Co) particles were formed completely at $600^{\circ}C$ for 3 h. The crystallization process, thermal decomposition and morphology of the $MWO_4$(M= Zn, Co) particles were evaluated. The characteristics of the SSM reaction and the formation of a high lattice energy by-product NaCl were discussed.

• Journal of the Korean Institute of Landscape Architecture
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• v.25 no.2
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• pp.54-61
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• 1997

This study has conducted to analyze the crelationship among soil properties and to investigate how they affect soil physical characteristics and plant growth. The experiment of woody plant growth was conducted as follows : Type I was the original soil. Type II, the soil particles smaller than 20${\mu}{\textrm}{m}$ was removed from the original soil. Type III, the soil particles is smaller than 75${\mu}{\textrm}{m}$ was removed from original soil. Wisteria floribunda A.P.DC and Celtis sinensisi Pers. were used for plant growth measurement. 1. Soil type II. the closest to Fuller's curved line, showed high dry bulk density and low in soil pores and saturated hydraulic conductivities. This created poor soil aeration and limited space for the root to growth. When the root did not have sufficient space to grow, there was a lot of physical stress, which hindered the root growth. 2. Soil typeIII was high saturated hydraulic conductivity and a lot of soil pores larger than 10 ${\mu}{\textrm}{m}$. As a result, there were more available spaces for root to spread. It was considered that there was less physical stress for root growth. Therefore, soil typeIII showed significantly greater root growth. 3. Because soil type III has less small particles and saturated hydraulic conductivity was high, and water infiltrates rapidly into the underground when there was rainfall or irrigation. The soil typeIII becomes much stronger soil mechanically due to the less small particles. Therefore, soil typeIII was a suitable material for applying on planting sites where soil compaction is expected.

• Horticultural Science & Technology
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• v.18 no.1
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• pp.33-38
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• 2000

This study was conducted in an effort to meet the need for domestic production of hydroponic media and for medium development using recycled hydroponic rockwool slabs. Two experiments were conducted to evaluate the growth of plug seedlings of petunia 'Romeo' in various mixtures including particles of used rockwool slabs (rockwool particles) and wood chips. In the first experiment, seedlings were grown in plugs filled with mixtures of steam- sterilized rockwool particles and chestnut wood chips, which had been weathered for six months and screened through either 2.8 mm or 5.6 mm sieve, at the mixing ratio of 100:0, 75:25, 50:50, 25:75, or 0:100 (v/v). In the second experiment, seedlings were grown in plugs filled with twenty different mixtures of steam-sterilized particles of used hydroponic rockwool slabs with 4 mm chestnut or pine wood chips, coir, peatmoss, or perlite. In the first experiment seedling growth was not affected by particle size of chestnut wood chips, was superior in the control (commercial plug medium) and in 100% rockwool particles, but was suppressed as mixing ratio of chestnut wood chips increased. In the second experiment, leaf length, and shoot fresh and dry weights were the greatest in rockwool particles+peatmoss+coir treatment, followed by rockwool particles+peatmoss treatment. Leaf length was suppressed as ratio of wood chips increased, especially of chestnut wood chips. Root development was the greatest in rockwool particles+peatmoss+perlite treatment, followed by the control, and rockwool particles+peatmoss+coir treatment. The growth was suppressed as the mixing ratio of rockwool particles, peatmoss, or coir decreased.