• Proceedings of the KSME Conference
• /
• 2000.04b
• /
• pp.404-409
• /
• 2000

Growth characteristics of silica particles have been studied experimentally using in situ sampling technique from $H_2/O_2TEOS$ diffusion flame with carefully devised sampling probe. Verification of sampling result was done through new method and effects of flame condition and TEOS flow rate on growth characteristics of silica particles were investigated. By comparing particles sampled by thermophoretic sampling in flame with those by collector sampling after probe, particles do not change before and after probe sampling, which was clearly proved from the fact that the result of TEM image analysis makes good agreement with that of SMPS measurement. As flame temperature increases, the effect of coalescence or sintering becomes important mechanism during growth of silica particles, resulting in canceling the effect of coagulation, which makes mean diameter of silica particles increase slowly. With increase in TEOS flow rate, the number concentration of generated silica particle increases but residence time of particles in flame decreases. As a result, there exists upper limit to which the diameter of silica particle increases under same flame condition.

• Korean Journal of Materials Research
• /
• v.25 no.10
• /
• pp.543-546
• /
• 2015

$TiO_2$ nanowires were grown by thermal oxidation of TiO powder in an oxygen and nitrogen gas environment at $1000^{\circ}C$. The ratio of $O_2$ to $N_2$ in an ambient gas was changed to investigate the effect of the gas ratio on the growth of $TiO_2$nanowires. The oxidation process was carried out at different $O_2$/$N_2$ ratios of 0/100, 25/75, 50/50 and 100/0. No nanowires were formed at $O_2$/$N_2$ ratios of less than 25/75. When the $O_2$/$N_2$ ratio was 50/50, nanowires started to form. As the gas ratio increased to 100/0, the diameter and length of the nanowires increased. The X-ray diffraction pattern showed that the nanowires were $TiO_2$ with a rutile crystallographic structure. In the XRD pattern, no peaks from the anatase and brookite structures of $TiO_2$were observed. The diameter of the nanowires decreased along the growth direction, and no catalytic particles were detected at the tips of the nanowires which suggests that the nanowires were grown with a vapor-solid growth mechanism.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.35 no.4
• /
• pp.68-74
• /
• 2003

Kenaf(Hibiscus cannabinus L.) cultivar, Tainung 2, had been grown for 152 days at the experimental farm of Jinju National University, Gajoa-dong, Jinju-si, Kyongnam, Korea. The planting, growth rate, fertilization and structural characteristics as well as the cultivation and growth characteristics of kenaf, and the product usage were investigated. The narrowest diameter at kenaf bottom was 10 mm, the widest 42 mm and the average about 28 mm, and the shortest height 150 cm, the tallest 480 cm and the average about 350 cm. The weight of a core fraction was 68.1％ and a bast fraction 31.9％. The weight ratio of core material to bast fiber was 2.31. The weight ratio of dry stem was 73.5％ and that of leaves 26.5％. The weight of dry plant produced in 1 $m^2$ was 1,467 g, and about 1,052 g of stem could be used for the commercial purpose, The application of fertilizers resulted in the increase of the growth rate of the diameter at plant bottom and the height. Bast fiber, phloem ray and cortex parenchyma cell were observed in bast, and vessel, wood fiber and ray in core.

• Journal of Bio-Environment Control
• /
• v.14 no.1
• /
• pp.1-6
• /
• 2005

A multipurpose operating system was developed to adjust both spray times and ventilation method without a configuration of the moving path and the type of the greenhouse. The multipurpose working system proved to be a reliable system for testing the growth quality of the fruit vegetables in the greenhouse. The results are as follows. The first leaf, diameter of a stem, leaf area, and average stem diameter in the Cucumber seedling growth were repressed by high-speed ventilation, but was not repressed by spray times. The first leaf in the Tomato seedling growth was repressed as ventilation velocity was high, but the average stem diameter was not repressed. While the Tomato was given water three times a day, the diameter of a stem and the leaf area were increased as ventilation speed became higher. However, those were different other factors. The Tomato leaf area was larger when given water twice a day than that in hand spray, but showed no difference with ventilation speed. The first leaf, the diameter of a stem and the leaf area of a Red pepper were lower in automatic spraying with ventilation than those in hand spray.

• Journal of Korean Society of Forest Science
• /
• v.96 no.6
• /
• pp.742-749
• /
• 2007

The objective of this study was to develop thinning effect analysis model (TEAM) using individual-tree distance-independent growth model of Pinus koraiensis Stands. The TEAM was designed to analyze thinning effects associated with such thinning prescriptions as the number, timing, intensity, and method of thinnings. To testing TEAM application, stand growth effects were compared with seven scenarios according to thinning prescription plan. In the results, it was possible to estimate the number of trees, height, volume with diameter (DBH) class of individual trees, and average diameter growth, height growth, the number of trees and volume growth per ha of stands. The result of sensitivity analysis on one Pinus koraiensis stand, it was not sure to expect the much more volume at the rotation age by stand density control applying thinning prescription. In the case of thinning, total yield volume has much more $40{\sim}75m^3$ per ha, within 5 cm in average diameter growth and within 1 m in average height growth than thats of non-thinning over increasing stand age. TEAM, as decision making support system, can be used for selecting the thinning prescription trial and determining one of some thinning prescription plan in different site specific stand environments.

• Journal of Korea Foresty Energy
• /
• v.23 no.2
• /
• pp.1-8
• /
• 2004

This study looked into the change of tree growth of seven forest growth monitoring plots which were set up at the Undulyeong Hongchungun Kangwondo, and was accomplished to offer the basic data for the forest administration calculating carbon storage and removal in the Undulyeong area. Annual height and DBH growth were slowly progressed in the Pinus koraiensis and Larix kaempferi stand which was young stand, but the growth rate of the other stands was lower than those young stand. The diameter class of the mixed forest and Qurcus mongilica stand was predicted to be similar to the now and Pinus koraiensis and Larix kaempferi stand was predicted to move now diameter class to the high diameter class because thickening growth speed of the those stands were rapid. Now the end of 2003, total carbon storage of the Undulyeong model forest increased 149,000TC$(2.7\%)$ compared with the previous year. Seeing by forest types, occupied broad-leaved forest$(50\%)$, mixed forest$(34\%)$ and coniferous forest. During in 2003, total carbon which was removed and stored according to growth of the forest was 156,813TC and net carbon removal(148,664TC) increased into 2,613TC$(1.8\%)$ compared with the previous year. Seeing by forest types, occupied coniferous forest$(3.3\%)$, mixed forest$(3.1\%)$, broad-leaved forest$(2.8\%)$. Resultingly, the Undulyeong model forest is acting to net removal resource when see as green-gas side and net carbon removal are showing the tendency to increase recently little by little.

• Asian-Australasian Journal of Animal Sciences
• /
• v.3 no.2
• /
• pp.125-133
• /
• 1990

The effect of dietary protein-energy restriction (PER) on the growth of long bone were examined in sheep during growing period and then following a cycle of reproduction. Three months-old female sheep were offered protein-energy restricted feed for 6 months (growing period), thereafter changed to normal nutritional conditions for 8 months (reproduction period). A half of animals in each group took pregnancy, parturition and lactation. The nutritional restriction reduced the growth in bone diameter more than that in bone length. Compensatory growth resulting from the removal of the nutritional restraint strongly occurred in bone diameter, especially the bone cortical width, as compared to bone longitudinal growth. A cycle of reproduction severely decreased the growth in the bone cortical width relative to that in the bone width, and little effect was found on the growth in bone length and bone mass. The depression of bone development by pregnancy and lactation tended to exhibit severer in animals having received normal nutrition than in those having received PER. Bone mineral density was not affected by the nutritional restriction. A cycle of reproduction had an adverse effect on the mineral density between in animals having received normal nutrition and in those having received PER.

• Journal of Chest Surgery
• /
• v.57 no.3
• /
• pp.231-239
• /
• 2024

Background: Although the modified Blalock-Taussig shunt remains the mainstay method of palliation for augmenting pulmonary blood flow in various congenital heart diseases, the shunt must be carefully designed to achieve the best outcomes. This study investigated the effect of shunt configuration on pulmonary artery growth and growth discrepancy. Methods: Twenty patients with successful modified Blalock-Taussig shunt takedown were analyzed. Pulmonary artery and shunt characteristics were obtained using computed tomography scans. Differences in the baseline and follow-up diameter ratios and growth in the ipsilateral and contralateral arteries were calculated. The angle between the shunt and pulmonary artery, as well as the distance from the main pulmonary artery bifurcation, were measured. Correlations between pulmonary arteries and shunt configurations were analyzed. Results: The median interval time between shunt placement and takedown was 154.5 days (interquartile range, 113.25-276.25 days). Follow-up values of the ipsilateral-to-contralateral pulmonary artery diameter ratio showed no significant correlation with the shunt angle (ρ=0.429, p=0.126) or distance (ρ=0.110, p=0.645). The shunt angle and distance from the main pulmonary bifurcation showed no significant correlation (ρ=-0.373, p=0.189). Pulmonary artery growth was negatively correlated with shunt angle (ipsilateral, ρ=-0.565 and p=0.035; contralateral, ρ=-0.578 and p=0.030), but not with distance (ipsilateral, ρ=-0.065 and p=0.786; contralateral, ρ=-0.130 and p=0.586). Conclusion: Shunt configuration had no significant effect on growth imbalance. The angle and distance of the shunt showed no significant correlation with each other. A more vertical shunt was associated with significant pulmonary artery growth. We suggest a more vertical graft design for improved pulmonary artery growth.

• Korean Journal of Materials Research
• /
• v.13 no.11
• /
• pp.756-760
• /
• 2003

Two dimensional computer simulations were conducted on percolative structure in which second phases with various short diameter were arranged in matrix phase. In case of prohibiting the overlap among the second phases, the maximum area fraction of second phase arranged in matrix was increased with higher short diameter. In case of allowing the overlap among the second phases, the critical area fraction was increased with higher short diameter and the total number of distributed second phase was decreased. This results represented that thickness variation of short diameter by grain growth on the production processes affect significantly forming the completion path.

• 한국생물공학회:학술대회논문집
• /
• 2002.04a
• /
• pp.45-47
• /
• 2002

Although Dacron and ePTFE have most widely been used for artificial vascular grafts, these materials cannot be used for small-diameter grafts (l.D.<6mm) due to thrombotic occlusion. To overcome this limitation, a small-diameter vascular graft was developed with stem cell and tissue engineering method. Autologous bone marrow stem cells were cultured and seeded onto small-diameter (4mm) collagen tubular matrices. The matrices were anastomosed to carotid arteries in canine models. Prior to implantation, histological and electron microscopical examination revealed stem cell adhesion and growth on the matrices. Angiography indicated that the vascular grafts maintained patent for 8 weeks. Histological examination showed the regeneration of endothelium, media and adventitia in the grafts. This study may allow us to step forward to the development of tissue-engineered small-diameter vascular graft appropriate for clinical applications.