• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.300-310
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• 2022

The objective of this experiment was to investigate the effect of drip irrigation volume on tomatoes (Solanum lycopersicum L.) grown in a greenhouse using perlite medium. Plants were treated by three different irrigation treatment I₀, I₂₅, and I₅₀ (where irrigation volume of I₂₅ and I₅₀ was 25% and 50% higher than I₀, having limited or no leaching). Growth characteristics of plants, yield and water use efficiency were measured. The result showed that plant height, leaf length and leaf width were lowest in the I₀ treated plants. However, these parameters were not statistically significant differences between the plants that were grown in the I₂₅ and I₅₀ treatment. Soluble solids content, acidity and dry matter of 111th, 132nd, and 143rd days harvested tomato were higher in the plants irrigated with lowest volume (I₀) than the higher volume (I₂₅ or I₅₀). In addition, water content was lower in the 111th and 132nd days of harvested tomatoes from the I₀ treatment. The number of big-size tomatoes (>180 g) was significantly higher in the I₂₅ irrigated plants. There was no significant difference in the total number of harvested fruits among the treatments. The average fruit weight and total yield of harvested tomatoes were lowest in the I₀ treated plants. The water consumption of tomato was not significantly different amongst the treatments but water use efficiency was lowest in the I₀ treatment. Principal component analysis revealed that total soluble solid and acidity of tomato showed a positive correlation between each other. These results suggest that I₂₅ was the optimum irrigation treatment for tomato based on its measured growth characteristics, yield and water use efficiency.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.3
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• pp.290-297
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• 2008

STATEMENT OF PROBLEM: Implant-supported fixed cantilever prostheses are influenced by various biomechanical factors. The information that shows the effect of implant number and position of cantilever on stress in the supporting bone is limited. PURPOSE: The purpose of this study was to investigate the effect of implant number variation and the effect of 2 different cantilever types on stress distribution in the supporting bone, using 3-dimensional finite element analysis. MATERIAL AND METHODS: A 3-D FE model of a mandibular section of bone with a missing second premolar, first molar, and second molar was developed. $4.1{\times}10$ mm screw-type dental implant was selected. 4.0 mm height solid abutments were fixed over all implant fixtures. Type III gold alloy was selected for implant-supported fixed prostheses. For mesial cantilever test, model 1-1 which has three $4.1{\times}10$ mm implants and fixed prosthesis with no pontic, model 1-2 which has two $4.1{\times}10$ mm implants and fixed prosthesis with a central pontic and model 1-3 which has two $4.1{\times}10$ mm implants and fixed prosthesis with mesial cantilever were simulated. And then, 155N oblique force was applied to the buccal cusp of second premolar. For distal cantilever test, model 2-1 which has three $4.1{\times}10$ mm implants and fixed prosthesis with no pontic, model 2-2 which has two $4.1{\times}10$ mm implants and fixed prosthesis with a central pontic and model 2-3 which has two $4.1{\times}10$ mm implants and fixed prosthesis with distal cantilever were simulated. And then, 206N oblique force was applied to the buccal cusp of second premolar. The implant and superstructure were simulated in finite element software(Pro/Engineer wildfire 2.0). The stress values were observed with the maximum von Mises stresses. RESULTS: Among the models without a cantilever, model 1-1 and 2-1 which had three implants, showed lower stress than model 1-2 and 2-2 which had two implants. Although model 2-1 was applied with 206N, it showed lower stress than model 1-2 which was applied with 155N. In models that implant positions of models were same, the amount of applied occlusal load largely influenced the maximum von Mises stress. Model 1-1, 1-2 and 1-3, which were loaded with 155N, showed less stress than corresponding model 2-1, 2-2 and 2- 3 which were loaded with 206N. For the same number of implants, the existence of a cantilever induced the obvious increase of maximum stress. Model 1-3 and 2-3 which had a cantilever, showed much higher stress than the others which had no cantilever. In all models, the von Mises stresses were concentrated at the cortical bone around the cervical region of the implants. Meanwhile, in model 1-1, 1-2 and 1-3, which were loaded on second premolar position, the first premolar participated in stress distribution. First premolars of model 2-1, 2-2 and 2-3 did not participate in stress distribution. CONCLUSION: 1. The more implants supported, the less stress was induced, regardless of applied occlusal loads. 2. The maximum von Mises stress in the bone of the implant-supported three unit fixed dental prosthesis with a mesial cantilever was 1.38 times that with a central pontic. The maximum von Mises stress in the bone of the implant-supported three-unit fixed dental prosthesis with a distal cantilever was 1.59 times that with a central pontic. 3. A distal cantilever induced larger stress in the bone than a mesial cantilever. 4. A adjacent tooth which contacts implant-supported fixed prosthesis participated in the stress distribution.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.3
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• pp.221-239
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• 2010

Bone loss may occur depending on the loading conditions. careful treatment planning and prosthetic procedures are very important factors for the proper distribution of stress. Evaluate the stress distributions according to numbers and location of implants in three-unit fixed partial dentures. A mandible missing the right second premolar, first molar and second molar was modeled. Using the CT data. we modeled a mandible with a width of 15mm, a height of 20mm and a length of 30mm, 2mm-thickness cortical bone covering cancellous bone mallow. An internal type implant and A solid type abutment was used. A model with 3 implants placed in a straight line, offset 1.5 mm buccally, offset 1.5 mm lingually and another model with 3 implants offset in the opposite way were prepared. And models with 2 implants were both end support models, a mesial cantilever model and a distal cantilever model. Three types of loading was applied; a case where 155 N was applied solely on the second premolar, a case where 206 N was applied solely on the second molar and a case where 155 N was applied on the first premolar and 206 N was applied on the first and second molar. For all the cases, inclined loads of 30 degrees were applied on the buccal cusps and vertical loads were applied on the central fossas of the teeth. Finite element analysis was carried out for each case to find out the stress distribution on bones and implants. This study has shown that prostheses with more implants caused lower stress on bones and implants, no matter what kind of load was applied. Furthermore, it was found out that inclined loads applied on implants had worse effects than vertical loads. Therefore, it is believed that these results should be considered when placing implants in the future.

• Journal of Aquaculture
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• v.15 no.2
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• pp.95-101
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• 2002

During the periods from lily to October, 2000 in Hongseong and lucy to October, 2001 in Taean in the west coast of Korea, the following environmental conditions prevailed : water temperature : 22.0~26.817, salinity 27.23 ~30.80%, dissolved oxygen 4.12 ~6.26 ml/l, pH 7.89 ~8.09, phosphate 0.39 ~0.65 $\mu m$ , inorganic nitrogen 5.05~9.26 $\mu m$, suspended solid 5.4~20.8 mg/l and chemical oxygen demand 1.12~1.87 mg/l. The B-shaped veliger larvae of the Ark shell occurred in maximum number at $25^{\circ}C$ prevailing from mid-August at Hongseong and Taean. Full grown larvae reached maximum abundance from late August. To identify the effectiveness of the substratum for spat collection, raschel net were tested to Larval settlement. The most effective depth to collect the larvae in natural environment was the collectors suspended at 7~8 m depth. At these depths, about 49 to 94 spats were found on the collector (40$\times$50 cm), The growth of shell height (Y) to shell length (X), and total weight (W) to shell length (L) could be formulated as follows respectively: Hongseong: SH = 0.7168 SL -0.6466 ( $r^2$ = 0.9839), TW = $0.0001SL^{3.1705}$ ($r^2$ = 0.9882) Taean: SH = 0.736 SL -0.8824 ($r^2$ : 0.9899), TW : 0.00005 $SL^{3.3731}$ ($r^2$ : 0.9899)

• Korean Journal of Environmental Agriculture
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• v.20 no.3
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• pp.180-185
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• 2001

Control effects of phosphorous acid were investigated on Phytophthora blight of red pepper plants in greenhouse and field. In vitro test, the mycelial growth of Phytophthora capsici was inhibited by the phosphorous acid more than 97% at 1,000 ${\mu}g$ and 10,000 ${\mu}g$ a.i./mL in the liquid and solid culture, respectively. At concentration of 10 ${\mu}g$ a.i./mL of phosphorous acid, in the liquid culture the mycelial growth of P. capsici was inhibited 46.2%, however inhibited only 4.9% on the soild culture. Zoosporangial formation was also inhibited 89.1% by phosphorous acid at 100 ${\mu}g$ a.i./mL. Phosphorous acid affected more zoosporangial formation of P. capsici than its mycelial growth. At the concentrations of 10,000, 1,000 and 100 ${\mu}g$ a.i./mL of phosphorous acid, germination of zoosporangia was inhibited 100, 84.3 and 44.2%, respectively. Mycelial growth and zoosporangial formation of P. capsici were little affected at the concentration of 10 ${\mu}g$ a.i./mL of phosphorous acid. Cermination of zoosporangia was also little affected at this concentration, however growth of the germ tubes was inhibited and the abnormal mycelial growth was observed. Phosphorous acid suppressed the incidence of Phytophthora blight of red pepper plants up to $77.0{\sim}62.0%$, in greenhouse. Phosphorous acid suppressed the incidence of Phytophthora blight of red pepper plants up to 54.0% at the conventional culture in field. Treatments of phosphorous acid increased up to 113% in height, 135% in number of fruit, and 129% in weight of fruit.

• Journal of Radiation Protection and Research
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• v.39 no.4
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• pp.199-205
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• 2014

In the field of neutron detections, $^3He$ gas, the so-called "the gold standard," is the most widely used material for neutron detections because of its high efficiency in neutron capturing. However, from variable causes since early 2009, $^3He$ is being depleted, which has maintained an upward pressure on its cost. For this reason, the demands for $^3He$ replacements are rising sharply. Research into neutron converting materials, which has not been used well due to a neutron detection efficiency lower than the efficiency of $^3He$, although it can be chosen for use in a neutron detector, has been highlighted again. $^{10}B$, which is one of the $^3He$ replacements, such as $BF_3$, $^6Li$, $^{10}B$, $Gd_2O_2S$, is being researched by various detector development groups owing to a number of advantages such as easy gamma-ray discrimination, non-toxicity, low cost, etc. One of the possible techniques for the detection is an indirect neutron detection method measuring secondary radiation generated by interactions between neutrons and $^{10}B$. Because of the mean free path of alpha particle from interactions that are very short in a solid material, the thickness of $^{10}B$ should be thin. Therefore, to increase the neutron detection efficiency, it is important to make a $^{10}B$ thin film. In this study, we fabricated a $^{10}B$ thin film that is about 60 um in thickness for neutron detection using well-known technology for the manufacturing of a thin electrode for use in lithium ion batteries. In addition, by performing simple physical tests on the conductivity, dispersion, adhesion, and flexibility, we confirmed that the physical characteristics of the fabricated $^{10}B$ thin film are good. Using the fabricated $^{10}B$ thin film, we made a proportional counter for neutron monitoring and measured the neutron pulse height spectrum at a neutron facility at KAERI. Furthermore, we calculated using the Monte Carlo simulation the change of neutron detection efficiency according to the number of thin film layers. In conclusion, we suggest a fabrication method of a $^{10}B$ thin film using the technology used in making a thin electrode of lithium ion batteries and made the $^{10}B$ thin film for neutron detection using suggested method.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.2
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• pp.125-140
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• 2011

The remnant of temporary cement on the intaglio surface of cast restoration may have a negative effect on the retentive strength of permanent cement. This study was to evaluate the effect of temporary cement cleaning methods on the retentive strength of cementation type implant prostheses. Prefabricated implant abutments - height 5.5mm, diameter 4.5mm, 6 degree axial wall taper with chamfer margins were used. Forty copings-abutment specimens were divided into four groups(each n=10) according to the cleaning methods for temporary cement(Temp-$Bond^{(R)}$) as follows : no temporary cementation(the control group), orange solvent, ultrasonic cleaning, air borne-particle abrasion. After the application of temporary cement and the separation, the cleaning procedure was performed according to the protocol of each group. The specimens were cemented with $Premier^{(R)}$ Implant $Cement^{TM}$. After the permanent cementation, the specimens were subjected to thermocycling and pulled out from the specimens with a universal testing machine at a cross-head speed of 0.5mm/min. After the retentive strength test, all the specimens were cleaned using ultrasonic cleaning, abraded with air borne-particles, and steam-cleaned. Likewise, the specimens were temporarily cemented(Temp-$Bond^{(R)}$ NE), cleaned according to the protocol of each group, cemented with $Premier^{(R)}$ Implant $Cement^{TM}$ and subjected to thermocycling and measurement of their retentive strength. The mean of group with orange solvent were significantly lower than those of other groups(p<0.05). There was no significance between group with ultrasonic cleaning and group with air borne-particle abrasion. Group with ultrasonic cleaning and group with air-particle abrasion were no significance at control group. There was no significance between group cemented with Temp-$Bond^{(R)}$ and group cemented with Temp-$Bond^{(R)}$ NE. Within the limitation of this study, it can be concluded that the temporary cement cleaning method with only orange solvent may have a negative effect on the retentive strength of permanent cement. Ultrasonic cleaning and air borne-particle abrasion methods are recommended for the temporary cement cleaning method on cementation type implant prostheses.

• Journal of Bio-Environment Control
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• v.14 no.2
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• pp.106-113
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• 2005

This study was carried out to develop a novel hydroponic medium far fruit vegetable crops by using waste synthetic fibers. In physical analysis of the synthetic fiber medium (SFM), the bulk density and percent solid phase were lower, while the porosity and water content were greater in comparison with the rockwool slab. The SFM had pH of 6.5 and EC of $0.03dS{\cdot}m^{-1}$ both of which are similar to those of the rockwool slab. The CEC of 0.39me/100mL of the SFM was lower than compared with 3.29me/100mL of the rockwool slab. However, concentrations K, Ca, Mg and Na were slightly higher in the SFM than those in the rockwool slab. The 'Momotaro' tomato crop in the SFM gave comparable plant height, stem diameter, days to first flowering, fruit weight and percent marketable yield as the rockwool slab. In the SFM and in the rockwool slab, mean fiuit weight were 182g and 181g, percent marketable yield were $93.8\%$ and $92.0\%$, respectively. The marketable yield per 10a in the SFM was 12,799 kg, which was $97\%$ of that in the rockwool slab. Growth parameters such as leaf length and width, leaf number, stem diameter and chlorophyll content of an exportable cucumber crop grown in the SFM and the rockwool slab were not different. Fruit weight was greater in the rockwool slab, while percent marketable yield was greater in the SFM. The marketable fruit yield per 10a of 5,062kg in the SFM was $2\%$ greater than that in the rockwool slab. $NO_3$ concentration in nutrient solution during the crop cultivation was higher in the SFM than in the rockwool slab, while concentrations $NH_4$, K, Ca, Mg and $SO_4$ were not different between the two media.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.601-609
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• 2021

The fructification characteristics, fruit quality, and yield of the 'Hwangsil' jujube tree were analyzed at various stages of growth age (3-8 years old) to obtain basic data for developing high-quality jujube production technology. The average height, crown area, stem diameter near the root, stem clear length, the number of the main branches, and the distance between any two main branches were 230.8 cm (224.4~247.2 cm), 3.0 m² (2.1~3.8m²), 4.8 cm (2.4~6.2 cm), 69.1 cm (46.6~78.0 cm), 12.9 (8.6~19.6), and 8.1 cm (7.4~9.0 cm), respectively. Tree age was positively correlated with the crown area, stem diameter near the root, but stem clear length negatively correlated with the number of main branches. The average number of fruits per mother bearing shoot and tree was 20.0 (14.3~26.3) and 302.8 (257.3~373.5), respectively. There was no correlation between tree age and fructification characteristics, such as the number of fruit-bearing mother shoots per the main branch, the number of fruit-bearing shoots per fruit-bearing mother shoot, and the number of fruits per fruit-bearing shoot. Since the shape of the jujube tree is constantly managed based onthe growing area and type of greenhouse where the tree grown. The average fruit weight, fruit hardness, and soluble solid content were 24.2 g (22.4~26.8 g), 28.4 N (27.3~30.0 N), and 19.0% (17.1~19.8%), respectively, with no correlation between the tree age and fruit quality. The average yield was 7.4 kg per tree (5.7~9.1 kg), with significantly high quantities were produced in six and seven years old trees.

• Journal of Astronomy and Space Sciences
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• v.36 no.1
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• pp.21-33
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• 2019

This paper focuses on the interpretation of radiation fluxes from active galactic nuclei. The advantage of positron annihilation spectroscopy over other methods of spectral diagnostics of active galactic nuclei (therefore AGN) is demonstrated. A relationship between regular and random components in both bolometric and spectral composition of fluxes of quanta and particles generated in AGN is found. We consider their diffuse component separately and also detect radiative feedback after the passage of high-velocity cosmic rays and hard quanta through gas-and-dust aggregates surrounding massive black holes in AGN. The motion of relativistic positrons and electrons in such complex systems produces secondary radiation throughout the whole investigated region of active galactic nuclei in form of cylinder with radius R= 400-1000 pc and height H=200-400 pc, thus causing their visible luminescence across all spectral bands. We obtain radiation and electron energy distribution functions depending on the spatial distribution of the investigated bulk of matter in AGN. Radiation luminescence of the non-central part of AGN is a response to the effects of particles and quanta falling from its center created by atoms, molecules and dust of its diffuse component. The cross-sections for the single-photon annihilation of positrons of different energies with atoms in these active galactic nuclei are determined. For the first time we use the data on the change in chemical composition due to spallation reactions induced by high-energy particles. We establish or define more accurately how the energies of the incident positron, emitted ${\gamma}-quantum$ and recoiling nucleus correlate with the atomic number and weight of the target nucleus. For light elements, we provide detailed tables of all indicated parameters. A new criterion is proposed, based on the use of the ratio of the fluxes of ${\gamma}-quanta$ formed in one- and two-photon annihilation of positrons in a diffuse medium. It is concluded that, as is the case in young supernova remnants, the two-photon annihilation tends to occur in solid-state grains as a result of active loss of kinetic energy of positrons due to ionisation down to thermal energy of free electrons. The single-photon annihilation of positrons manifests itself in the gas component of active galactic nuclei. Such annihilation occurs as interaction between positrons and K-shell electrons; hence, it is suitable for identification of the chemical state of substances comprising the gas component of the investigated media. Specific physical media producing high fluxes of positrons are discussed; it allowed a significant reduction in the number of reaction channels generating positrons. We estimate the brightness distribution in the ${\gamma}-ray$ spectra of the gas-and-dust media through which positron fluxes travel with the energy range similar to that recorded by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) research module. Based on the results of our calculations, we analyse the reasons for such a high power of positrons to penetrate through gas-and-dust aggregates. The energy loss of positrons by ionisation is compared to the production of secondary positrons by high-energy cosmic rays in order to determine the depth of their penetration into gas-and-dust aggregations clustered in active galactic nuclei. The relationship between the energy of ${\gamma}-quanta$ emitted upon the single-photon annihilation and the energy of incident electrons is established. The obtained cross sections for positron interactions with bound electrons of the diffuse component of the non-central, peripheral AGN regions allowed us to obtain new spectroscopic characteristics of the atoms involved in single-photon annihilation.