• Journal of Bio-Environment Control
• /
• v.7 no.1
• /
• pp.15-24
• /
• 1998

The greenhouse temperature controls in general have been managed by the above-ground part environment, But the temperature of root zone was known very important factor for the 9rofth and the yield of vegetables in greenhouse. The purpose of this study is to develop a good method for cultivation using solar energy which can apply warming soil and to develop the greenhouse soil temperature automatic control system. Followings are summary of this study：1 When the greenhouse inner temperature changes were about 24$^{\circ}C$ during a day in October, the temperature of non-warmed soil was differenced 6$^{\circ}C$ in the depth 10cm and 3$^{\circ}C$ in the depth 20cm. 2. When water supply temperature was kept at 40, 50 and 6$0^{\circ}C$, the lowest soil temperature in the depth of 10cm is 2$0^{\circ}C$ and that of 20cm was 23$^{\circ}C$. and when the water supply temperature was over 4$0^{\circ}C$, the space heating temperature did not affect the temperature variation of soil. 3. In comparison with conditions of the warmed and non-warmed soil, when the water supply temperature is 28$^{\circ}C$, soil temperatures had the high temperature of 4$0^{\circ}C$~7$^{\circ}C$ in the depth of 10cm to 20 cm. 4. The line of boundary area was appeared in the depth of 15~20cm, 13~19cm and 12~17cm. when the water supply temperature was 4$0^{\circ}C$, 5$0^{\circ}C$ and 6$0^{\circ}C$. 5. When th inner greenhouse air temperature is maintained over 11$^{\circ}C$ and the water supply temperature is supported 28$^{\circ}C$, the lowest temperature is kept up over 2$0^{\circ}C$.

• Journal of Bio-Environment Control
• /
• v.26 no.2
• /
• pp.100-107
• /
• 2017

This experiment was carried out to analyze the effects of substrate reuse on the growth and yield of summer paprika in cyclic hydroponics. The test group was divided into a new coco slab, one year reused coco slab two year reused coco slab based on 30% nutrient solution reuse, and was performed from April 18 to November 31, 2016 for 30 weeks. As a result, plant height of early growth was that the 2 year reused slab was longer than the new slab but the final growth period was 56.58 cm shorter. First group flower position was that reused slab was shorter by 2.92 cm than the new slab and the second group flower position was 0.31 cm long. The relative internode length of early growth, when the reused slab was used, the imbalance in the late growth stage was increased compared with the use of the new slab. The number of growth nodes in the 1 and 2 year reused slab was the smallest with 27.4 nodes. However, the number of harvested nodes did not show the difference in the test group, and the ratio of harvested that the 2 year reused slab was the highest at 26.8%. The ratio of unmarketable fruit tended to increase as the growth progressed. Fresh weight was 227.7g for new slab, 219.2g for 2 year reused slab and 21.2g for 1 year reused slab. The dry weight of the new slab increased with the reuse of the slab. It was 17.13g for new slab, 18.26g for 1 year reused, and 19.28g for 2 year reused. The average water content of the entire growth period was smaller as the slab was reused, and the 1 year reused slab was about 20g less than the 2 year reused slab. This trend was steadily occurring throughout the entire growing season. Especially, the reused slab for 1 year was less than 60g after 3 groups compared to other test groups. In conclusion, If will control seriously occurrence of unmarketable fruits by weakening after medium growth in summer-cultivated paprika in EC-based recycling hydroponic cultivation with reused cocopeat substrate, It is not what I have to worry that decrease of the yield and deterioration of the quality due to the change of physical and chemical properties of the slab and the pathogenic bacteria infection.

• Progress in Medical Physics
• /
• v.21 no.2
• /
• pp.209-217
• /
• 2010

Retinal prostheses are being developed to restore vision for the blind with retinal diseases such as retinitis pigmentosa (RP) or age-related macular degeneration (AMD). Since retinal prostheses depend upon electrical stimulation to control neural activity, optimal stimulation parameters for successful encoding of visual information are one of the most important requirements to enable visual perception. Therefore, in this paper, we focused on retinal ganglion cell (RGC) responses to different voltage stimulation parameters and compared threshold charge densities in normal and rd1 mice. For this purpose, we used in vitro preparation for the retina of normal and rd1 mice on micro-electrode arrays. When the neural network of rd1 mouse retinas is stimulated with voltage-controlled pulses, RGCs in degenerated retina also respond to voltage amplitude or voltage duration modulation as well in wild-type RGCs. But the temporal pattern of RGCs response is very different; in wild-type RGCs, single peak within 100 ms appears while in RGCs in degenerated retina multiple peaks (~4 peaks) with ~10 Hz rhythm within 400 ms appear. The thresholds for electrical activation of RGCs are overall more elevated in rd1 mouse retinas compared to wild-type mouse retinas: The thresholds for activation of RGCs in rd1 mouse retinas were on average two times higher ($70.50{\sim}99.87\;{\mu}C/cm^2$ vs. $37.23{\sim}61.65\;{\mu}C/cm^2$) in the experiment of voltage amplitude modulation and five times higher ($120.5{\sim}170.6\;{\mu}C/cm^2$ vs. $22.69{\sim}37.57\;{\mu}C/cm^2$) in the experiment of voltage duration modulation than those in wild-type mouse retinas. This is compatible with the findings from human studies that the currents required for evoking visual percepts in RP patients is much higher than those needed in healthy individuals. These results will be used as a guideline for optimal stimulation parameters for upcoming Korean-type retinal prosthesis.

• Journal of Wetlands Research
• /
• v.22 no.3
• /
• pp.194-199
• /
• 2020

Unlike in the past, the world is facing water shortages due to climate change and difficulties in simultaneously managing the risks of flooding. The Four Major Rivers project was carried out with the aim of realizing a powerful nation of water by managing water resources and fostering the water industry, and the construction period was relatively short compared to the unprecedented scale. Therefore, the prediction and analysis of how the river environment changes after the Four Major Rivers Project is insufficient. Currently, part of the construction section of the Four Major Rivers Project is caused by repeated erosion and sedimentation due to the effects of sandification caused by large dredging and flood-time reservoirs, and the head erosion of the tributaries occurs. In order to solve these problems, the riverbed maintenance work was installed, but it resulted in erosion of both sides of the river and the development of new approaches and techniques to keep the river bed stable, such as erosion and excessive sedimentation, is required. The water agent plays a role of securing a certain depth of water for the main stream by concentrating the flow so much in the center and preventing levee erosion by controlling the flow direction and flow velocity. In addition, Groyne products provide various ecological environments by forming a natural form of riverbeds by inducing local erosion and deposition in addition to the protection functions of the river bank and embankment. Therefore, after reviewing the method of determining the shape of the Groyne structure currently in use by utilizing the mobile limit flow rate and marginal reflux force, a new Critical Movement Velocity(${\bar{U}}_d$) and a new resistance coefficient formula considering the mathematical factors applicable to the actual domestic stream were developed and the measures applicable to Groyne installation were proposed.

• The Korean Journal of Mycology
• /
• v.41 no.2
• /
• pp.57-66
• /
• 2013

The mushrooms collected at seven areas of Mt. Chiak in 2002 and 2003 were classified to analyse the distribution and species diversity. Frequency (number of mushroom : N), number of species (S), relative species density (RSD), similarity index (C), richness index (R1), variety index (V1), evenness index (E2), and dominance index(D1) were investigated. Total N and S was 143 and 84, respectively. The RSD was 0.179 ~ 0.226 of the 7 areas. The yearly C of the total area (0.213) was 8.2%. more higher than the average C of 7 areas (0.131). The order in the coefficient of variation (CV) of the indicator for 7 areas was N (10.5%) > D1 (9.2%) > V1 (8.9%) > S (8.5%) > R1 (7.4%) > E2 (2.2%). The average R1 of the 7 areas was 5.36 with the range from 4.85 to 6.01, and 16.72 for the total area. The average V1 of the 7 areas was 16.24 with the range from 14.44 to 18.66, and 68.82 for the total area. The average E2 of the 7 areas was 0.95 with the range from 0.926 to 0.982, and 0.819 for the total area. The average D1 of the 7 areas was 0.071 with the range from 0.055 to 0.073, and 0.081 for the total area. The correlation between N and 5 kinds of diversity indicator (S, R1, V1, E2, D) was not statistically significant, but the correlation between R1, E2 and D1 was statistically significant each other.

• Journal of Korean Society of Forest Science
• /
• v.82 no.4
• /
• pp.354-365
• /
• 1993

The purpose of this investigation is to point out the physical fixation and stability of banking slopes of forest roads by invasion of trees. We investigated the situations of sediment discharge and coverage of invaded trees at banking slopes of forest roads. The coverage of invaded trees were calculated from crown injection based on the stable slope and was compared with length of slope, slope gradient, and passage years after construction of forest road. 1. We investigated on the sediment discharge and the invasion of trees at banking slopes, which were actually observed 8 forest roads of Kyonggi-Do and Kangwon-Do. 2. There was no physical stability of the banking slope due to the surface erosion and slope failure, but the tree invasions were active at the stable plots. 3. The length of slope was constructed to 4.0m to 61.0m and recent forest road was mainly constructed to the slopes longer than 30m. There was strong regional effect between the length of slope and the coverage of invaded trees and the above two factors were inversely proportional to each other. 4. There was no significant relationship between the slope gradient and the coverage of invaded trees and the slope constructed within the angle of repose showed the relatively high coverage of invaded trees. 5. There was no significant relationship between the passage years and the coverage of invaded trees in the same investigative region after the construction of forest road. But there was a gradually increasing relationship of tree invasion between above two factors. However, there was some limitation to expect the invasion of the tree species. 6. In the light of the above results, we suggest that the construction of forest road may need foundation work and vegetation work simultaneously for the physical stability to make the environment of tree plantation and that the reasonable increase of construction cost of forest road may be prior to the other factors.

• Economic and Environmental Geology
• /
• v.43 no.2
• /
• pp.163-176
• /
• 2010

We report twenty data for early lavas erupted during the initial period of formation of Jeju Island on the basis of review on 539 data of whole-rock greochemistry and $^{40}Ar/^{39}Ar$ age dating out of mainly core samples from 69 boreholes drilled in the lower land since 2001 and 66 outcrop sites. Out of 69 boreholes, the early lava flow units are identified from samples collected from Beophocheon (EL 235 m, 210 m deep), Donnaeko (EL 240 m, 230 deep), Donghong-S (EL 187 m, 340 m deep), 05Donghong (EL. 187.6 m, 340 m deep), Dosoon (EL 305 m, 287 m deep), Sangye (EL 230 m, 260 m deep), Mureung-1 (EL 10.2 m, 160 m deep), and Gapa (EL 17.5 m, 92 m deep), which are located in the southern and southwestern portion of Jeju Island. While, the well-known outcrops from Sanbangsan, Wolrabong, Wonmansa, and Kagsubawi are also reconfirmed. $^{40}Ar/^{39}Ar$ age dating results of these lavas range from 1 Ma to 0.7 Ma, indicating that the data can be useful to constrain on age and geochemical characteristics of early lava effusion period in the formation of Jeju Island. Especially, samples with trachybasalt in composition collected from 143 m to 137 m, and from 135 m to 123 m below ground surface at 05Donghong hole have the oldest ages, $992\pm21$ Ka and $988\pm38$ Ka, respectively. This study suggests that in Jeju Island the first lava with trachybasalt in composition may have effused around 1 Ma ago, and the effusion style and chemical compositions of lavas must have changed to the formation of lava domes with trachyte-trachyandesite-basaltic trachyandesite and the eruption of lavas with alkali basalt and trachybasalt intermittently during the period from 0.9 Ma to 0.7 Ma ago. It also indicates that the initial lava flows below the ground are intercalated with or underlain by the Seoguipo Formation except for several exposed domal structure areas such as Sanbangsan and Kagsubawi, implying that the early lava effusion may have intermittently and sporadically occurred with nearby hydrovolcanism and sedimentation.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.11 no.2
• /
• pp.110-116
• /
• 2003

This study was executed to evaluate the utilization and efficiency of the ceramic biocarrier as the promoter of decomposing on the organic matters for the composting using with pig manure by analyzing of the physico-chemical properties during composting. The treatments of this experiment were consisted of the control(C),microorganism(M), M with natural zeolite(M+Z), M with synthesized zeolite(M+SZ), and M with ceramic biocarrier(M+CZ). The process term of composting was conducted for 30days in the rapidly fermented machine(as pilot system). The results of the physico-chemical properties of the composts were as follows. The changes of temperature during composting was not relative with the microorganism and zeolite materials used in the composts. At all of the treatments were similar to changing of temp. from the initial stage to the final stage. But the added microorganism treatments were higher than control. And the entire pH value of treatments were appeared the same that above temperature result, also the M+CZ and M+SZ treatment among the treatment were higher. At the results of T-C, T-N and C/N ratio, in case of T-C value, the M+CZ treatment was highly more decreased than others. However at the T-N value, there were not the differences from the each treatment. And the C/N ratio was changed according to the changes of T-C and T-N value. Especially, at the M+CZ aud M+SZ treatments were remarkably reduced by about 21.4-23.3 value. In the result of G.I for evaluating of the compost humidity, the M+CZ and M+SZ treatments were close up approximately 110 value compared with the control(G.I value 100). Therefore, the examined ceramic biocarrier amended with compost-promoting-bacteria could be applied to the production of many high quality fertilizers. It is also expected that the results of this researches could be applied to the recycle of the organic wastes based on the experimental results of ceramic biocarrier and compost-promoting-bacteria application.

• Korean Journal of Poultry Science
• /
• v.32 no.3
• /
• pp.149-156
• /
• 2005

Two experiments were conducted to examine the effects of betaine intake on blood and yolk cholesterol, abdominal fat, liver fat, tissue triglyceride(TG) and liver HMG-CoA reductase In laying hens. In Expt. 1, a total of 72 ISA-brown laying hens were individually assigned into four treatments from 18 to 21 weeks old. Com-soybean meal based diet were fed with the addition of 0, 300, 600 and 1,200ppm. In Expt. 2, 72 ISA-brown laying hens were housed into individual cage to evaluate the effect of dietary betaine(0, 600ppm) and energy(ME, 2,800, 2,900kca/kg) from 70 to 74 weeks. Serum total cholesterol, LDL and HDL-cholesterol and TG concentration in blood of hens fed betaine tended to increase compared to those of the control, but were not significantly different. However, betaine supplementation showed a statistically significant decrease in yolk cholesterol(P<0.05). There was no significant difference in abdominal fat among the treatments. Liver fats and 7c of birds 130 betaine was decreased compared with control. Serum total cholesterol, LDL-cholesterol and triglyceride concentration were significantly inc.eased by ffeding a diet containing 600ppm betaine in Expt. 2(P<0.05), but were not influenced by the dietary energy levels. Yolk cholesterol, abdominal fat and HMG-CoA reductase activity were affected neither by dietary energy nor betaine level.

• Korean Journal of Poultry Science
• /
• v.38 no.1
• /
• pp.29-35
• /
• 2011

An experiment was conducted to investigate the effects of dietary supplementation of a silicate mineral (D Lite) on growth performance, nutrient retention, carcass characteristics and meat quality in broiler chicks. A total of 640 broiler chicks were randomly allotted to four dietary treatments in a randomized complete block design. Each treatment had four replicates comprising 40 broilers in each replicate. Dietary treatments were as follows: control (0% D Lite), and diets supplemented with 0.15%, 0.30% and 0.45% of D Lite. The starter and finisher diets were fed from d 0 to 21 and d 21 to 35, respectively. Body weight gain during starter (p<0.05), finisher (p=0.057) and overall (p<0.001) experimental period and feed intake (p<0.05) during starter period decreased quadratically with increasing dietary D Lite levels. The birds fed 0.15% D Lite showed the greatest (p<0.05) overall weight gain, feed intake and retention of gross energy and calcium. There were no differences (p>0.05) in carcass characteristics, organ weights and breast meat composition. However, as the level of D Lite was increased in the diet there was a linear decrease in the TBARS values of breast meat (p<0.05) at d 12 of storage. These results suggest that D Lite supplementation at the level of 0.15% is shown to be effective in improving performance and nutrient retention in broilers.