• Horticultural Science & Technology
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• v.29 no.1
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• pp.10-15
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• 2011

The influence of root zone temperature to the induction of inflorescence and growth of Phalaenopsis was investigated. Root zone temperatures were 15, 20, 25, and $30^{\circ}C$, while the air temperature was kept over $28^{\circ}C$ during three months. $CO_2$ uptake, fresh weight, dry weight and branched root number of Phalaenopsis were highest at $25^{\circ}C$ and lowest at $15^{\circ}C$. But, the anthocyanin content was highest at $15^{\circ}C$ and lowest at $25^{\circ}C$. Inflorescence was not induced by root zone cooling temperature below $25^{\circ}C$ for three months. The concentrations of K, Ca and Mg in leaves were changed according to the root zone temperature, but those of N and P were not changed. K content was high at $20^{\circ}C$, whereas Ca and Mg contents were high at $25^{\circ}C$ root zone temperature. This study indicates that Phalaenopsis perceives temperature by shoot and the optimum root-zone temperature for the vegetative growth is $25^{\circ}C$.

• Applied Chemistry for Engineering
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• v.16 no.5
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• pp.648-652
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• 2005

A super ionic conductor, $K^+$-beta-aluminas, which is known to be difficult to obtain in the form of dense sintered density under atmospheric pressure, was pulverized to 350 nm mean particle size using attrition mill. The sample were pressed into tablet form by uniaxial pressing. The specimen was sintered under atmospheric pressure in powder form. Sintering temperature range was $1400^{\circ}C$ to $1650^{\circ}C$ at $50^{\circ}C$ intervals. Additionally, zone sintering was carried out to control the growth grain at high temperature ($1600^{\circ}C$). The density of specimens that were sintered at $1600^{\circ}C$ and $1650^{\circ}C$, and sintered at $1600^{\circ}C$ by zone sintering were about 93% and 95%, respectively. In the case of the lengthened sintering time to 2 h, the density of specimen was reduced to lower than 90%, since the particles were grown to the duplex microstructure.

• Journal of the Korean Geotechnical Society
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• v.16 no.3
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• pp.39-46
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• 2000

본 논문에서는 배수재가 설치된 구역과 설치되지 않은 구역으로 구성된 Olga-C 시험성토지반의 변형률속도 의존적인 압밀거동을 서술하였다. 배수재가 설치된 지반이 압밀거동에 대한 변형률속도의 영향을 해석하기 위하여 응력-변형률-변형률 속도의 관계식(v-$\varepsilon$v- v)을 이용한 축대칭 비선형 점소성 모델을 제안하였다. 제안된 모델은 실험실과 현장의 변형률속도 차이뿐만 아니라 간극수압의 소산과 생성의 복합적인 압밀과정을 고려할 수 있다. 연직 및 반경방향의 배수효과에 의해 배수재가 설치된 지반(Zone B)에서 유발되는 변형률 속도는 배수재가 설치되지 않은 연약지반 (Zone A)의 변형률 속도보다 크다. 유발된 변형률 속도의 영향으로 Zone B의 선행압밀하중도 Zone A에서 유발되는 선행압밀하중보다 크다. Olga-C 지역의 Zone A 에서는 응력완화효과가 유발되지만, Zone B에서는 응력완화효과가 유발 되지 않았다.

• Journal of Korea Foundry Society
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• v.17 no.4
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• pp.393-401
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• 1997

Commercial flake graphite cast iron substrate was coated with titanium powder by low pressure plasma spraying and was irradiated with a $CO_2$ laser to produce the wear resistant composite layer. From the experimental results of this study, it was possible to composite TiC particles on the surface layer by direct reaction between carbon existed in the cast iron matrix and titanium with thermal sprayed coating by remelting and alloying them using laser irradiation. The cooling rate of laser remelted cast iron substrate without titanium coating was about $1{\times}10^4$ K/s to $1{\times}10^5$ K/s in the order under the condition used in this study. The microstructure of alloyed layer consisted of three zones, that is, TiC particule crystallized zone (MHV $400{\sim}500$), the mixed zone of TiC particule+ledebulite (MHV $650{\sim}900$) and the ledebulite zone (MHV $500{\sim}700$). TiC particules were crystallized as a typical dendritic morphology. The secondary TiC dendrite arms were grown to the polygonized shape and were necking. And then the separated arms became cubic crystal of TiC at the slowly solidified zone. But in the rapidly solidified zone of fusion boundry, the fine granular TiC particules were grouped like grape.

• Journal of Welding and Joining
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• v.33 no.5
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• pp.53-60
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• 2015

Laser surface Melting Process is getting hardening layer that has enough depth of hardening layer as well as no defects by melting surface of substrate. This study used CW(Continuous Wave) Yb:YAG and STD11. Laser beam speed, power and beam interval are fixed at 70mm/sec, 2.8kW and 800um respectively. Hardness in the weld zone are equal to 400Hv regardless of melting zone, remelting zone overlapped by next beam and HAZ. Similarly, microstructures in all weld zone consist of dendrite structure that arm spacing is $3{\sim}4{\mu}m$, matrix is ${\gamma}$(Austenite) and dendrite boundary consists of ${\gamma}$ and $M_7C_3$ of eutectic phase. This microstructure crystallizes from liquid to ${\gamma}$ of primary crystal and residual liquid forms ${\gamma}$ and $M_7C_3$ of eutectic phase by eutectic reaction at $1266^{\circ}C$. After solidification is complete, primary crystal and eutectic phase remain at room temperature without phase transformation by quenching. On the other hand, microstructures of substrate consist of ferrite, fine $M_{23}C_6$ and coarse $M_7C_3$ that have 210Hv. Microstructures in the HAZ consist of fine $M_{23}C_6$ and coarse $M_7C_3$ like substrate. But, $M_{23}C_6$ increases and matrix was changed from ferrite to bainite that has hardness above 400Hv. Partial Melted Zone is formed between melting zone and HAZ. Partial Melted Zone near the melting zone consists of ${\gamma}$, $M_7C_3$ and martensite and Partial Melted Zone near the HAZ consists of eutectic phase around ${\gamma}$ and $M_7C_3$. Hardness is maximum 557Hv in the partial melted zone.

• Journal of Bio-Environment Control
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• v.17 no.1
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• pp.14-19
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• 2008

The experiment was investigated the effects of lower root zone temperature on shoot and root growth of 'Akihime' strawberries in aeroponics in cold season. Root growth was decreased with decrease of root zone temperature, especially in lateral roots. Elongation of main roots was highest in $18^{\circ}C$ of root zone temperature. Number of lateral roots and length of lateral roots were lowest in $8^{\circ}C$ of root zone temperature. Lower root zone temperature resulted significantly in decrease of fresh weight of root and shoot and leaf area of strawberry. But there were no significant statistical differences in shoot fresh weight and leaf area in $8^{\circ}C$ and $13^{\circ}C$ of root zone temperature. Leaf length, leaf width and number of leaves of strawberry were decreased in lower root zone temperature. The results of this experiment will be utilized in the winter season cultivation for strawberry in hydroponics.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.1
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• pp.65-75
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• 2012

To study the difference in growth characteristics between intertidal and subtidal eelgrass Zostera marina populations, environmental factors and changes in tissue carbon (C) and nitrogen (N) contents in eelgrass from the lower intertidal and upper subtidal zones were surveyed monthly in the Seomjin Estuary from May 2003 to December 2004. Water temperatures, water column nutrient concentrations, sediment pore water, and ammonium and phosphate concentrations showed no significant differences between intertidal and subtidal zones. Sediment pore water nitrate+nitrite concentrations were slightly higher in the intertidal zone than in the subtidal zone. Average monthly exposure times in the intertidal and subtidal zones were $42.4{\pm}5.8h\;month^{-1}$ and $15.3{\pm}3.5h\;month^{-1}$, respectively. Eelgrass leaf N content decreased from March to August and increased from September to February in the subtidal zone, whereas these trends were not observed in the intertidal zone. Eelgrass rhizome C content increased from April to September and decreased from October to March in the subtidal zone, whereas those tendencies were not recorded in the intertidal zone. Eelgrass rhizome C:N ratios showed a strong reverse trend to leaf C:N ratios in the subtidal zone, but these tendencies were not observed in the intertidal zone. The effects of exposure appeared to cause no seasonal trend in eelgrass tissue C and N content or C:N ratios in the intertidal zone in the Seomjin Estuary.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.04b
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• pp.39-40
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• 2001

This experiment was conducted to investigate the effect of root zone heating on the growth of cut minirose Rosa hybrida L. ′Little Marble′ in winter season. Effects of four different root zone temperatures of 16, 20, 24$^{\circ}C$ and non-heating control on the growth and productivity were compared. Harvested cut-flowers were measured for stem length, stem diameter, fresh and dry weights, numbers of leaves, stems and flowers, days to flower, and chlorophyll concentration. The results showed that mean height was the greatest at 16$^{\circ}C$. Days to flower was the shortest at 24$^{\circ}C$. Fresh and dry weights of top (shoot＋leaf＋flower), shoot and leaf were the greatest at 2$0^{\circ}C$. Stem and flower numbers were the greatest at 16$^{\circ}C$, but leaf number was the greatest at 2$0^{\circ}C$. Mean cut flower yield was the greatest at 16$^{\circ}C$. Chlorophyll concentration was slightly higher at 16$^{\circ}C$, but was not significantly different among the treatments. Stem diameter was the greatest at 2$0^{\circ}C$. Dry matter was the greatest at 24$^{\circ}C$. Total yield of cut rose stems increased with increasing temperature. Combined heating could save 24% in fuel cost as compared to the air heating alone. The results obtained suggested that optimal root zone temperature for the growth of cut rose "Little Marble" was 2$0^{\circ}C$, and the greenhouse heating energy can be saved by minimal air heating combined with root zone heating to 2$0^{\circ}C$.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.278-285
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• 2001

Aluminum/Aramid Fiber Reinforced Plastic(Al/AFRP) laminates are applied to the fuselage-wing intersection. The main objective of this study was to evaluate the delamination zone behavior of Al/AFRP with a saw-cut and circular hole using average stress criterion and the effect of notch geometry. Mechanical tests were carried out to determine the cyclic-bending moment and delamination zone observed ultrasonic C-scan pictures. In case of Al/AFRP containing saw-cut specimen, the shape and size of the delamination zone formed along the fatigue crack. However, in case of Al/AFRP containing circular hole specimen, the shape and size of delamination zone formed two types. first type, delamination zone formed along the fatigue crack. Second type, not observed fatigue crack. Therefore, delamination zone was formed dependently of the circular hole shape.

• Journal of Bio-Environment Control
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• v.4 no.2
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• pp.152-158
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• 1995

This experiment was undertaken in order to clarify effect of NO$_3$-N/NH$_4$-N ratios(NO$_3$/NH$_4$ : 10:0, 8:2) in the nutrient solution on growth, yield, photosynthetic rate, relative concentration of chlorophyll and root activity of hydroponically grown pepper plants at three different root- zone temperatures of 18$^{\circ}C$, 22$^{\circ}C$ and 26$^{\circ}C$. Plant height, leaf number, stem diameter, fresh and dry weight of leaf and root were no effect in by three root- zone temperatures. However, leaf number, stem diameter, fresh and dry weight of leaf and stem, dry weight of root at 18$^{\circ}C$, 22$^{\circ}C$ and $25^{\circ}C$ increased when NH$_4$-N was added to the solution. Under root-Bone temperatures of 18$^{\circ}C$, 26$^{\circ}C$ condition, fruit length were longer by the addition of NH$_4$-N. Fruit number and yield increased by the addition of NH$_4$-N at three root-zone temperatures. Photosynthetic rate decreased as root - zone temperature increased. Under root-zone temperatures of 18$^{\circ}C$, 22$^{\circ}C$ and 26$^{\circ}C$ condition, photosynthetic rate increased significantly by the addition of NH$_4$-N. Chlorophyll content of plants increased at 22$^{\circ}C$. Under root-zone temperatures of 18$^{\circ}C$, 22$^{\circ}C$ and 26$^{\circ}C$ condition, chlorophyll content of plants increased by the addition of NH$_4$-N. Root activity of increased at 26$^{\circ}C$ Under root-Bone temperatures of 18$^{\circ}C$, 22$^{\circ}C$ and 26$^{\circ}C$ condition, root activity increased by the addition of NH$_4$- N.