• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.5
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• pp.242-245
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• 2009

AlN crystals were grown by a sublimation process without seed crystals and the growth morphology of them was characterized. The grown AlN crystals were a polycrystalline phase, which had a diameter of $60\sim200\;{\mu}m$ and were grown with a growth rate of $0.2\sim0.5\;{\mu}n/hr$. It was observed that the as-grown crystals had a hexagonal crystal structure and revealed that these crystals were grown with a morphology of columnar morphology in the initial stage of the growth before they were enlarged in a way of a lateral growth behavior in the final stage. On the surface, a lot of pinholes were observed on the surface of crystals grown. The evolution of a growth morphology was characterized by optical and scanning electron microscopic observation.

• The korean journal of orthodontics
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• v.20 no.1
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• pp.135-156
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• 1990

This study was undertaken to investigate the difference of chin morphology and mandibular form in relation to different mandibular growth direction. The subject was divided into three group i.e., control group, vertical group, and horizontal group, according to the criteria of $Bj{\ddot{o}}rk$ sum, and each group was composed of 15 females and 15 males. Medial axis analysis in addition to the routine cephalometric analysis using P.I.A.S. (personal image analysing system) was carried out to find out the differences of mandibular morphology on each group. The results were as follows: 1. The area of symphysis was larger in horizontal growth group than that of vertical growth group. 2. Protruding chin area was also larger in horizontal growth group than that of vertical growth group. 3. There was a close correlationship between protruding chin area and other form of mandible. 4. Antegonial notch depth and ramus posterior contour depth was deeper in vertical growth group than in horizontal growth group, and antegonial notch depth was more influenced by anterior part of notch than posterior part of notch. 5. Mental medial axis and incisal medial axis length, in relation to corpus medial axis length was larger in vertical growth group than in horizontal growth group.

• 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.

• The Korean Journal of Ceramics
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• v.2 no.4
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• pp.221-225
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• 1996

In diamond synthesis by metal film growth method under high pressure and high temperature, the nucleation and growth of diamond was observed dependent on the carbon source variation from graphite powder to the heat treated powders of lamp black carbon. At the low driving force condition near equilibrium pressure and temperature line, nucleation of diamond did not occur but growth of seed diamond appeared in the synthesis from lamp black carbon while both nucleation and growth of diamond took place in the synthesis from graphite. Growth morphology change of diamond occurred from cubo-octahedron to octahedron in the synthesis from graphite but very irregular growth of seed diamond occurred in the synthesis from lamp block carbon. Lamp black carbon transformed to recrystallized graphite first and very nucleation of diamond was observed on the recrystallized graphite surface. Growth morphology of diamond on the recrystallized graphite was clear cubo-octahedron even at higher pressure departure condition from equilibrium pressure and temperature line.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.281.1-281.1
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• 2013

Shape control of gold nanocrystal is still one of the most important challenges remaining to achieve geometry dependent properties. Thus far, several strategies have been developed to control the shape of nanoparticles, such as adding capping agents and diverse additives or adjusting the temperature and pH. Here, we used an already established seed-mediated method that allowed us to focus on controlling the growth stage. Cetyltrimethylammonium bromide (CTAB) and ascorbic acid (AA) were used as the ligand and the reducing agent, respectively, without using any additional additives during the growth stage. We investigated how the relative ratio of CTAB and AA concentrations could be a major determinant of nanoparticle shape over a wide concentration range of CTAB and AA. As a result, a morphology diagram was constructed experimentally that covered the growth conditions of rods, cuboctahedra, cubes, and rhombic dodecahedra. The trends in the morphology diagram emphasize the importance of the interplay between CTAB and AA. Furthermore, high-index faceted gold nanocrystal was obtained by two step seeded growth. Already synthesized cubic particles developed into hexoctahedral nanocrystal consisting of 48 identical {321} facets, which indicates that the growth of gold nanocrystal is affected by initial morphology of seed particles. The hexoctahedral gold nanoparticles can be used in catalysis and optical applications which exploiting their unique geometry. Our research can provide useful guidelines for designing various facetted geometries.

• Korean Journal of Materials Research
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• v.12 no.1
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• pp.36-43
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• 2002

In this study, the nanosized ZnS thin films that can be used for fabrication of blue light-emitting diodes, electro-optic modulators, and n-window layers of solar cells were grown by the solution growth technique (SGT), and their surface morphology and film thickness and grain size dependence on the growth conditions were examined. Based on these results, the quantum size effects of ZnS were systematically investigated. Governing factors related to the growth condition were the concentration of precursor solution, growth temperature, concentration of aq. ammonia, and growth duration. X-ray diffraction patterns showed that the ZnS thin film obtained in this study had the cubic structure ($\beta$-ZnS). With decreasing growth temperature and decreasing concentration of precursor solution, the surface morphology of film was found to be improved. Also, the film thickness depends largely on the ammonia concentration. In particular, this is the first time that the surface morphology dependence of ZnS film grown by SGT on the ammonia concentration is reported. The energy band gaps of samples were determined from the optical transmittance values, and were shown to vary from 3.69 eV to 3.91 eV. These values were substantially higher than 3.65 eV of bulk ZnS. It was also shown that the quantum size effect of SGT grown ZnS is larger than that of the ZnS films grown by most other growth techniques.

• Proceedings of the Korean Magnestics Society Conference
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• 2000.05a
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• pp.144-145
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• 2000

• Proceedings of the Korean Magnestics Society Conference
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• 2001.04a
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• pp.102-103
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• 2001

• Korean Journal of Crystallography
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• v.5 no.2
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• pp.93-99
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• 1994

Growth form and surface morphology of NYAB single crystal grown by TSSG technique using a K2O/3MoOS/0.5B203 flux was investigated. In the crystal grown from <100> or <120> seed, prismatic and (101) faces were well developed with different size each other. (001) face was also developed in the crystal grown from <001> seed. While growth hillocks were observed on the prismatic face of the crystal grown from <100> seed, surface striations parallel to neighbor (101) faces were formed on that face of the crystal grown from <001> seed. The (101) faces were grown by two dimensional nucleation growth. (001) face which was developed at slow growth velocity of [001] direction was grown by screw dislocation Anisotropy of growth velocity as to seed orientation affected on crystal morphology and surface morphology.

• The korean journal of orthodontics
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• v.26 no.5 s.58
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• pp.601-611
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• 1996

Craniofacial growth pattern is an important diagnostic data in the course of orthodontic diagnosis and treatment planning ; it also has great influence in the establishment of occlusion as well as shaping and development of face. There have been many studies to classify different craniofacial growth patterns and attempts to predict growth patterns. This study aimed to correlate craniofacial growth pattern and symphysis morphology. 120 adult patients with age from 19 to 39 (mean age : 23.1) were chosen as subjects , using lateral cephalometric films. their anterior to posterior facial height ratios were calculated. They were divided into 3 groups - clockwise growth pattern with $56\%-62\%$(36subjects), counter-clockwise growth pattern group with $65\%$-80\%$(43subjects) and normal growth pattern group with $62\%-65\%$(41subjects). Symphysis morphology and Prominence evaluation in each subject were studied and the following conclusions were drawn : 1. In comparison of symphysis morphology between the sex groups, men showed large symphysis height and prominence. 2. Concerning the symphysis morphology, the clockwise growth pattern group showed larger height, H/D ratio and actual length but smaller depth, angle, effective length and E/A ratio compared to the counter -clockwise growth pattern group. 3. Those with smaller prominance of symphysis showed clockwise growth tendency and those with larger prominance showed counter-clockwise growth tendency.