• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.375-382
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• 2021

For stable cultivation in double cropping, it is important to use potato (Solanum tuberosum L.) cultivars with a short dormancy period of 50-70 days and plant seed tubers of appropriate type and size. An experiment was conducted during 2018-2019 to investigate the effects of seed tuber type and size on growth and yield performance in double cropping. Whole tubers of three sizes (10-20 g, 30-40 g, and 50-60 g) and conventional cut tubers weighing 30-40 g from three cultivars with different dormancy periods, namely 'Daeji' (40-60 days), 'Eunsun' (50-60 days), and 'Saebong' (50-80 days), were planted, and their field performance was compared. Regardless of the cultivar, the increase in the whole tuber weight up to 30-40 g led to fast emergence, thereby increasing ground cover rate, shoot growth rate, and tuber growth rate, which ultimately improved tuber yield by 33-54%. Comparing the whole and cut tubers, 'Daeji' and 'Eunsun' showed similar growth and yield performance; as such, the performance of whole tubers weighing 10-20 g was comparable to that of cut tubers weighing 30-40 g. However, 'Saebong', a cultivar with relatively long dormancy period, performed better with cut tuber than with whole tubers. Based on these results, we recommend the use of whole tubers weighing over 30 g for double cropping. Further studies to break tuber dormancy are warranted in cultivars with relatively long dormancy periods (50-80 days), such as 'Saebong'.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.87-90
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• 1973

Optimum plot shape and size in a uniformity trial in the newly founded experimental farm of KAERI were determined for seed yield with the basic units consisted of 2.5m $\times$ 0.6m plot. Various plot sizes and shapes were made by combination of the basic units. Coefficients of variations for yield were 21% in local branch type variety Kumkang-Dairip and 20% in the introduced branchless type variety Clark. This result indicates that the field in the new experimental farm is appropriate for soybean yield trials when adequate number of replications are employed in the field experiment. In general, C. V. values were gradually decreased with increase of plot sizes. Although the data were not consistant, the errors for the long narrow plots tend to have somewhat smaller than for the square shape plots. A sharp decrease in C.V. value was found from the $4.5\textrm{m}^2$ plot in the variety Kumkang-Dairip and from the $6\textrm{m}^2$ plot in the variety Clark. These results imply that 5-$6\textrm{m}^2$ plot could be used for yield trials in early generations of hybrid progenies. 2.5-5m long plot with 3-4 replications will be practical for yield trials in the early hybrid generations. The C.V. values with 7.5m long plot was about 16% in both varieties and 15.3% in 10m plot. These results indicate that 7.5-10m plot with 3-4 replications could be employed in accurate yield test in the advanced generations.

• Korean Journal of Plant Resources
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• v.30 no.1
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• pp.78-87
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• 2017

This study was compared to outdoor field (OF) and rain shelter greenhouse (RSG) according to cultivation type of Gastrodia elata Blume. Also, the effects of yield and quality for mulching materials in RSG were compared. The yield of G. elata was investigated good merchantable quality, and the quality was investigated hardness, chromaticity, weight loss and the contents of the major functional components. The cultivation of RSG was increased the yield, hardness, gastrodin, and vanillyl alcohol compared to OF, and the weight loss, chromaticity, and ergothioneine were almost equal. Rice straw treatment showed higher than those of the control and other treatments on the yield and hardness. As a result, the yield and the quality of RSG, which can control the soil moisture, were better than that of OF. And the lower the soil moisture content according to the mulching material, the harder the surface and the higher the hardness.

• Preventive Nutrition and Food Science
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• v.3 no.4
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• pp.303-308
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• 1998

Influence of amylose content on formation and characteristics of enzyme-resistant starch (RS) was investigated by scanning electron microscopy, X-ray diffractometry and differential scanning calorimetry. RS yield increased up to 36.1 % as the amylose content of corn starch increased. Starch granules of Amyulomaize V and Ⅶ were more rounded and smaller than those of regular corn ; some were elongated and had appendages. After autoclaving -cooling cycles, the granular structure disappeared and a continous spongy-like porous network was visible in regular corn starch ; the granular structure was stillevident in parts in Amylomaize V and Ⅶ starches. In all isolated RS residues , the porous structures were no longer visible and more compact formations predominated. While regular corn starch showed an A-type X-ray profile, Amylomaize V and Ⅶ starches exhibited a combination of B- and V-types. Regular corn starch lost most of its crystallinity during autoclaving , but the crystallinity was still left in Amylomaize starches as diffuse or poor B-types. All RS residues showed the presence of poor B-type regardless of amylose contents. Transition temperatures and enthalypy of native starches were a little higher in Amylomaize V and Ⅶ starches than those of regular corn starch . Regardless of amylose contents, all RS residues exhibited an endothermic transition over a similar temperature range (135 $^{\circ}C$~169$^{\circ}C$), with a mean peak temperature of ~154$^{\circ}C$, which is generally foud for retrograded amylose crystallities. Higher transition temperature, enthalypy, and RS yield of AMylomaize V and Ⅶ starches were related granular stability shown by the microscopic and crystallographic studies.

• Journal of Mushroom
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• v.6 no.1
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• pp.38-41
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• 2008

Studies were processed to confirm the difference of the shiitake productivity according to different spawn shapes(sawdust, plug-shaped and liquid spawns) on middle-temperature type strain. A tendency of fruiting was similar among three treatments, and treatments inoculated with plug-shaped spawn and liquid spawn produced over 50 % of total yield until 2nd flushing period and 80 % of total yield until 4th flushing period. In investigation of deformed fruit-bodies, all of three treatments occurred until 2nd flushing period. However, in rate of deformed fruit-bodies, treatment inoculated with liquid spawn was lower than others. In investigation of yield, the amount produced on treatment inoculated with liquid spawn was 411 g per medium and it was highest among treatments. And the amount of fruit-bodies over 10 g was higher than others. Also, the number of fruit-bodies between sawdust and plug-shaped spawn was different, but each weight of fruit-bodies among three treatments was not different.

• International Journal of Korean Welding Society
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• v.3 no.2
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• pp.40-45
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• 2003

A series of experiments has been carried out to investigate the effect of titanium, boron and nitrogen on the microstructure and toughness of simulated heat affected zone (HAZ) in quenched and tempered (QT) type 490MPa yield strength steels. For acquiring the same strength level, the carbon content and carbon equivalent could be lowered remarkably with a small titanium and boron addition due to the hardenability effect of boron during quenching process. Following the thermal cycle of large heat input, the coarsened grain HAZ (CGHAZ) of conventional quenched and tempered (QT) type 490MPa yield strength steels exhibited a coarse bainitic or ferrite side plate structure with large prior austenite grains. While, titanium and boron bearing QT type 490MPa yield strength steels were characterized by the microstructure in the CGHAZ, consisting mainly of the fine intragranular ferrite microstructure. Toughness of the simulated HAZ was mainly controlled by the proper Ceq level, and the ratio of Ti/N rather than titanium and nitrogen contents themselves. In the titanium­boron added QT steels, the optimum Ti/N ratio for excellent HAZ toughness was around 2.0, which was much lower than the known Ti/N stoichiometric ratio, 3.4. With reducing Ti/N ratio from the stoichiometric ratio, austenite grain size in the coarse grained HAZ became finer, indicating that the effective fine precipitates could be sufficiently obtained even with lower Ti/N level by adding boron simultaneously. Along with typical titanium carbo­nitrides, various forms of complex titanium­ and boron­based precipitates, like TiN­MnS­BN, were often observed in the simulated CGHAZ, which may act as stable nuclei for ferrite during cooling of weld thermal cycles

• International Journal of Concrete Structures and Materials
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• v.18 no.2E
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• pp.79-87
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• 2006

The main objective of this research is to examine the behavior of high-strength concrete(HSC) columns. Eight test columns in one-third scale were tested under the conditions of cyclic lateral force and a constant axial load equal to 30% of the column axial load capacity. The $200{\times}200mm$ square columns were reinforced with eight DB bars constituting a longitudinal steel ratio of 2.54% of the column cross-sectional area. The main experimental parameters were volumetric ratio of transverse reinforcement(${\rho}_s$=1.58, 2.25 percent), tie configuration(Type H, Type C, Type D) and tie yield strength($f_{yh}$=548.8 and 779.1 MPa). It was found that the hysteretic behaviour and ultimate deformability of HSC columns were influenced by the amount and details of transverse reinforcement in the potential plastic hinge regions. Columns of transverse reinforcement in the amount 42 percent higher than that required by seismic provisions of ACI 318-02 showed ductile behavior. At 30% of the axial load capacity, it is recommended that the yield strength of transverse reinforcement be held equal to or below 548.8 MPa. Correlations between the calculated damage index and the damage progress are proposed.

• Architectural research
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• v.7 no.1
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• pp.39-48
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• 2005

Main objective of this research is to evaluate performance of high-strength concrete (HSC) columns for ductility and strength. Eight one-third scale columns with compressive strength of 69 MPa were subjected to a constant axial load corresponding to 30 % of the column axial load capacity and a cyclic horizontal load-inducing reversed bending moment. The variables studied in this research are the volumetric ratio of transverse reinforcement (${\rho}_s=1.58$, 2.25 %), tie configuration (Type H, Type C and Type D) and tie yield strength ($f_{yh}=549$ and 779 MPa). Test results show that the flexural strength of every column exceeds the calculated flexural capacity based on the equivalent concrete stress block used in the current design code. Columns with 42 % higher amounts of transverse reinforcement than that required by seismic provisions of ACI 318-02 showed ductile behaviour, showing a displacement ductility factor (${\mu}_{{\Delta}u}$) of 3.69 to 4.85, and a curvature ductility factor (${\mu}_{{\varphi}u}$) of over 10.0. With an axial load of 30 % of the axial load capacity, it is recommended that the yield strength of transverse reinforcement be held equal to or below 549 MPa.

• Journal of Bio-Environment Control
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• v.19 no.1
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• pp.12-18
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• 2010

Irrigation management methods controlled by integrated solar radiation (ISR) or drainage level sensor were evaluated in rockwool or coir bag culture as tomato (Solanum lycopersicum L.) production system. Substrate water content and drainage percentage were more stable in the drainage level sensor method than in the ISR method regardless of substrate type. Total yield and marketable yield were high in the drainage level sensor method, but not between substrates in the same irrigation management method. Sugar content was affected more by the substrate type than irrigation method. The drainage level sensor method was elucidated to be better than the ISR method regardless of substrate type.

• Structural Engineering and Mechanics
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• v.64 no.2
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• pp.183-194
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• 2017

This paper presents the experimental investigation into a new type of steel-concrete hybrid outrigger system developed for the high-rise building structure. The steel truss is embedded into the reinforced concrete outrigger wall, and both the steel truss and concrete outrigger wall work compositely to enhance the overall structural performance of the tower structures under extreme loads. Meanwhile, metal dampers of low-yield steel material were also adopted as a 'fuse' device between the hybrid outrigger and the column. The damper is engineered to be 'scarified' and yielded first under moderate to severe earthquakes in order to protect the structural integrity of important structural components of the hybrid outrigger system. As such, not brittle failure is likely to happen due to the severe cracking in the concrete outrigger wall. A comprehensive experimental research program was conducted into the structural performance of this new type of hybrid outrigger system. Studies on both the key component and overall system tests were conducted, which reveal the detailed structural response under various levels of applied static and cyclic loads. It was demonstrated that both the steel bracing and concrete outrigger wall are able to work compositely with the low-yield steel damper and exhibits both good load carrying capacities and energy dispersing performance through the test program. It has the potential to be applied and enhance the overall structural performance of the high-rise structures over 300 m under extreme levels of loads.