• Korean Journal of Medicinal Crop Science
• /
• v.23 no.1
• /
• pp.43-48
• /
• 2015

This study was carried out in order to investigate the photosynthesis response and leaf characteristics of Peucedanum japonicum growing in forest farming. The experiment was performed by leaf mold (pine tree and chestnut tree) and shading levels (0%, 35%, 50% and 75% shading). Light relative intensity was 100% (full sunlight), 60.3% (35% shading), 35.1% (50% shading), and 17.4% (75% shading) respectively. Light response curves of pine-leaf mold and chestnut-leaf mold were the highest in control (full sunlight) and these were getting lower in the higher shading level. Photosynthesis capacity and light saturation point were indicated higher in chestnut-leaf mold within the same shading level. As the shading level increased, maximum photosynthesis rate decreased. And apparent quantum yield was not indicated statistically significant difference from all treatment. Leaf area, leaf length and leaf width were significant higher in 35% shading and control under chestnut-leaf mold in all treatment. As the shading level increased, LAR (leaf area ratio), SLA (specific leaf area) and SPAD value decreased in pine-leaf mold and chestnut-leaf mold. As a result of surveying the whole experiment, P. japonicum is judged better growth and higher yield by maintaining 35% shading (relative light intensity 60%) under chestnut-leaf mold in forest farming.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.7 no.3
• /
• pp.73-77
• /
• 2004

The purpose of this study was to improve the ornamental value of Perilla frutescens var. acuta. The growth of Perilla frutescens var. acuta was significantly varied as according to light intensities. The plant height, crown width, petiole length, leaf length, leaf width, stem diameter, and chlorophyll content were the greatest with 30% shade treatment. All of growth characteristics decreased as increasing shading levels. The anthocyanin contents also decreased with 70% shading level. The leaf color turned from dark purplish red to deep yellowish green, and the growth rate and ornamental value were the lowest with 70% shading condition.

• KIEAE Journal
• /
• v.13 no.4
• /
• pp.21-26
• /
• 2013

Shading devices have become an integral part of the daylighting strategy for sustainable classroom design. The louver type is newly designed shading devices which provide more view to the outside and protect from outside condition such as snow or rain. The purpose of this study is to compare the daylight performance of traditional and louver type overhang and lightshelf. The room dimension was $7.5m{\times}9.0m{\times}3.0m$. The length of shading devices was calculated by Palmero's study. The length of the traditional and louver type overhang was 455mm, 1210mm and lightshelf was 350/810mm, 625/555mm respectively. For the study, the Radiance 2.0 was used to evaluate the illuminance and uniformity ratios. And scale model were used to evaluate sunpatch area on the floor in model was calculated. The results showed that the louver type lightshelf was suitable for spring and summer, and louver type overhang was suitable for winter.

• Horticultural Science & Technology
• /
• v.17 no.1
• /
• pp.29-32
• /
• 1999

This experiment was conducted to investigate the effect of different levels of shading (0, 35, 55, 75, 95% to incident sunlight) on the growth of Hedera rhombea Bean and Pachysandra terminalis Sieb. et Zucc. in order to determine optimum light intensity for ground cover plants. H. rhombea showed a upright growth type under 95% shading and P. terminalis was highest under 35% shading. Number of branches was not significantly affected by shading levels. Stem diameter and length were reduced under shading from 35% to 95%. Leaf growth was vigorous under 35% and 55% shade condition. Leaves became longer with decreasing light intensity, but shorter in 95% shading than control. There was a slight trend that total chlorophyll and chlorophyll a, b contents increased with decreasing light intensity, and so did chlorophyll a/b ratio. Fresh and dry weight of both plants were higher under 35, 55, and 75% shading than control and 95% shading. Specific leaf weight tended to decrease with reduction of light intensity. Thus, optimum light intensity for growth of them may be 35 and 55% shading of incident sunlight. In addition, it is possible to grow them under even 75% shading of incident sunlight.

• Journal of the Korean Solar Energy Society
• /
• v.25 no.2
• /
• pp.27-33
• /
• 2005

To improve the performance of the top-positioning space in buildings, we suggested the environment-friendly system integrating various design techniques in the previous paper. This work discussed to calculate the length of PV considering a part of metallic radiators for radiative cooling, an critical element of the whole system, for shading not to prevent the PV on roof from generating electricity. In the process of calculating the shading area, we used the geometrical relationship between the sun-rays and the variable roof. For general applications, we utilized DL, the ratio of the length of PV and that of metallic radiator on roof, as a design factor, and then used the maximum insolation and the specific insolation($200W/m^2$) to decide the distance off the axis of rotation. As a result, for DL, we found out the reasonable value of 1.0 with full covering, 1.2 with 90%, and 2.0 with 70% in PV covering.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.69 no.1
• /
• pp.15-24
• /
• 2024

Environmental factors play an important role in crop growth and development. In recent years, climate change has become a challenge that limits environmental factors. Light is an important environmental factor for photosynthesis in rice. In addition, temperature is one of the most important factors for rice production; thus, a 1℃ increase in temperature because of climate change can affect rice growth and development. Therefore, we investigated the effect of shading on the growth characteristics of rice under different temperature conditions from the vegetative stage to the flowering stage. Plants were grown at three different temperatures: 26℃/16℃ for 21℃, 29℃/19℃ for 24℃, and 22℃/32℃ for 27℃ in a phytotron. A 55% shade treatment was applied after 10 days of transplanting until the flowering stage. Plant height was not affected by the shading treatment. In the maximum tiller number response to shading, a lower tiller number and growth speed of tiller was found in the 27℃ condition. Among leaf characteristics, shading increased the flag leaf area, length, width, and effective leaf area; however, it decreased the leaf number on the main stem, especially at 27℃. In terms of stem characteristics, shading affected culm wall thickness in both varieties. Finally, regarding the panicle characteristics, lower panicle numbers, spikelet numbers per panicle, primary numbers, and secondary numbers per panicle were found under the shading treatment. Most of the desirable characteristics were affected by the shading treatment at 27℃. Overall, these results indicated that shading had a greater effect on rice plant growth at high temperature.

• Journal of Korean Association for Spatial Structures
• /
• v.19 no.2
• /
• pp.83-90
• /
• 2019

Most of the variable shading devices are installed outdoors, so they are greatly affected by structural safety due to external climate change, wind, rain, and snow. Especially, due to strong wind such as typhoons, safety problems may occur due to the dropout of the device. Therefore, it is necessary to secure the structural safety against the wind. Therefore, it is necessary to analyze the structural behavior of the windshield to evaluate the structural safety of the variable sunshade device. In this study, we analyze the wind pressure applied to the shading material according to the change of the length of the variable shading device, and apply it to the calculation of the wind load for the structural design of the variable shading device. The CFD (Computational Fluid Dynamic) analysis of the structure of the sample was used to analyze wind pressure magnitude and distribution. In order to estimate the wind pressure, the maximum wind loads of the static and negative pressures acting on the structure were analyzed from numerical simulation results.

• Korean Journal of Medicinal Crop Science
• /
• v.9 no.1
• /
• pp.1-7
• /
• 2001

This experiment was carried out to investigate the effects of shading treatments and harvesting methods on the growth of Eleutherococcus senticosus, which was known as the medicine of anticancer, anti-stress, hepatic detoxification activity, immunoactivity, and tonic. Light transmission ratio and air temperature were decreased as $40{\sim}64%$,$1.9{\sim}2^{\circ}C$, respectively, in 30% to 70% shading net treatment compared to non-shading. Fifty percentage shading net treatment was effective for the growth and yield of Eleutherococcus senticosus. During summer Eleutherococcus senticosus was growing under shading net treatment compared to non-shading. Tunnel type was more effective for growth than vertical type in shading method. 30cm length included 2 to 3 nodes cutting from soil surface was the most effective for branching stem length, plant height and yield as harvesting methods.

• Journal of the Korean Institute of Navigation
• /
• v.6 no.2
• /
• pp.35-55
• /
• 1982

The attempt of this paper is to examine the basic theory on the analysis of the effect of a shading coil fitted to an electromagnetic contactor, and to compare experimentally the attracting force of an AC electromagnetic contactor with that of a DC electromagnetic contactor, with varying the airgap length. Equations are also proposed for calculating the AC and DC attracting force per unit consumption wattage by using the circuit constants measured from the experiment, and these calculated attracting forces are compared with those actulally measured, and then, the experimental contactor is examined in the view of its design. The calculated attracting forces are appeared to coincide well with the measured ones and the experimental contactor fitted with shading coil is revealed not so well designed for reducing the fluctuation of the attracting force.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.11 no.6
• /
• pp.104-111
• /
• 2008

Plant growth and variegated leaf color changes of three leaf variegated Sedum spectabile varieties 'Variegatum', 'Frosty Morn', red colored 'Washfield Ruby', and one Sedum lineare variety 'Variegatum' and Sedum sarmentosum under three levels of shading conditions were examined for leaf ornamental value improvement. Shading levels were 40%($1,500{\mu}mol{\cdot}m-^2{\cdot}s-^1$), 70%($750{\mu}mol{\cdot}m-^2{\cdot}s-^1$) and 85%($375{\mu}mol{\cdot}m-^2{\cdot}s-^1$). Improvements of leaf ornamental value of 'Variegatum' 'Frosty Morn' and 'Washfield Ruby' were observed at 40% shading level and plant heights and leaf sizes were also increased. Plant height of S.sarmentosum were shorten under direct sun light condition and leaf color changed to greenish yellow(RHS143B) but deep green color(RHS144A) was observed under shading conditions. Endurance of S.sarmentosum was stronger than other species and leaf ornamental values remained well at 70% shading level. Leaf width of S.lineare 'Variegatum' were not changed under shading conditions but leaf length was increased. Leaf color was Deep green color was greenish yellow under direct sun light but deepest green color was observed at 85% shading level. Consider all ornamental value criteria, best shading conditions for S.lineare 'Variegatum' were ranged 40% to 70%.