• Korean journal of applied entomology
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• v.10 no.2
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• pp.117-120
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• 1971

This experiment was carried out to obtain basic informations on the development in sterile-male technique of rice stem borer. The species considered is Chile suppressalis Walker. Different developmental stages of the insect namely; larval, pupae and adult were irradiated with $Co^{60}$ gamma ray. The results obtained were as follows: 1) A 1:1 sex ratio in the pupal stage was observed. 2) In the pupal stage sub-lethal dosages$(LD_{50})$ were 26 KR and 26.7 KR for female and male, respectively. 3) The total number of egg masses per female increased with the increasing gamma ray dosages and average number of eggs produced per female decreased in the cross between normal female and irradiated male. 4) The sterile dosage $(SD_{90})$ of the gamma ray irradiation showed 23 KR in the male. 5) The pupal stage is most convenient developmental stage for irradiation.

• Physical Therapy Korea
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• v.2 no.2
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• pp.9-23
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• 1995

The objective of this study was to identify the effects of weight-transfer training on the weight bearing distribution and gait patterns of hemiplegic patients through visual and auditory feedback using a limb load monitor. The subjects of this study were 18 hemiplegic patients who had been hospitalized or were visited out-patient department of the Rehabilitation Hospital, College of Medicine, Yonsei University, from January 5, 1995 through March 15, 1995. Pre-and post-training changes in gait patterns were measured using ink foot prints as well as by recording weight bearing distribution using a limb load monitor. The data were analyzed by the repeated measure one-way ANOVA and paired t-test. The finding were as follows: 1. Prior to the training, 18 subjects bore more weight on the sound leg(61.6 %) than on the affected leg(38.4 %). 2. Posterior to the training, the average percentage of weight bearing on the affected leg increased significantly from 38.4 % prior to training; to 46.0 % immediately after training; 45.7 % after a 30 second delay; and 45.3 % after a 60 second 3. The difference in gait patterns between pre- and post- training was statistically significant, with an increase in gait velocity to 3.65 cm/sec post-training; an increase in stride length to 5.37 cm on the affected side; 4.77 cm on the sound side; and a narrowing of the base of support to 1.19 cm. In conclusion, hemiplegic weight-transfer training using visual and auditory feedback with a limb load monitor was found to be enhancing symmetrical standing posture, and simultaneously improve gait patterns.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.3
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• pp.43-51
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• 1986

Triaxial compression tests were performed with control of vertical stress, confined pressure(${\sigma}_H$), and injection velocity by means of impervious soil samples with a different grain size, density and grout density. By measuring pore water pressure at the time of vertical fracturing around the bore-hole, relationships between main factors are described, and the factors are pore water pressure, confined pressure, vertical fracturing injection pressure(${\sigma}$) and the tension strength(${\sigma}_t$). The hydraulic fracturing of soft clay was occurred at the pressure which was less than the pressure obtained by the theory of elasticity. It was found that the above result was the influence of pore water pressure due to injection pressure($U_a$) and pore water pressure due to confined pressure($U_i$). Therefore, the vertical injection pressure at the time of fracturing needs to be changed as follows. $${\sigma}=2{\cdot}{{\sigma}_H}-(U_a+U_i)+{\sigma}_t$$.

• Geomechanics and Engineering
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• v.3 no.3
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• pp.189-206
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• 2011

Amplification based on empirical relations is widely used for seismic microzonation of urban centers. Amplifications are used to represent the site effects of a particular soil column. Many empirical correlations are available to estimate the amplification of seismic waves. These correlations are based on the ratio of shear wave velocity of foundation/rock to soil velocity or 30 m equivalent shear wave velocity ($Vs^{30}$) and are developed considering deep soil data. The aim of this work is to examine the applicability of available amplification relations in the literature for shallow engineering bedrock sites by carrying out site response studies. Shear wave velocity of thirteen sites having shallow engineering bedrock have been selected for the study. In these locations, the depth of engineering bedrock (> 760 ${\pm}$ 60 m/s) is matched with the drilled bore hole. Shear wave velocity (SWV) has been measured using Multichannel Analysis of Surface Wave survey. These sites are classified according to the National Earthquake Hazards Reduction Program (NEHRP) classification system. Amplifications for an earthquake are arrived for these sites using empirical relations and measured SWV data. Site response analysis has been carried out in SHAKE using SWV and using synthetic and real earthquake data. Amplification from site response analysis and empirical relations are compared. Study shows that the amplification arrived using empirical relations does not match with the site response amplification. Site response amplification is much more than empirical values for same shear wave velocity.

• Parasites, Hosts and Diseases
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• v.41 no.1
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• pp.17-25
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• 2003

The tegumental ultrastructure of juvenile and adult Himasthla alincia (Digenea: Echinostomatidae) was observed by scanning electron microscopy. One-, 5- (juveniles) and 20-day-old worms (adults) were harvested from chicks experimentally fed metacercariae from a bivalve, Mactra veneriformis. The juvenile worms were elongated and cu wed ventrally. The head crown bore 31 collar spines, arranged in a single row. The lip of the oral sucker had 12 paired, and 3 single type 1 sensory papillae, and the ventral sucker had about 25 type II sensory papillae. The anterolateral surface between the two suckers was densely packed with tegumental spines with 4-7 pointed tips. The adult worms were more elongated and filamentous, and had severe transverse folds over the whole body surface. On the head crown and two suckers, type 1 and 11 sensory papillae were more densely distributed than in the juvenile worms. Retractile brush-like spines, with 8-10 digits, were seen on the anterolateral surface, whereas claw-shaped spines, with 2-5 digits, were sparsely distributed posteriorly to the ventral sucker The cirrus characteristically protruded out, and was armed with small spines distally. The surface ultrastructure of H. alincia was shown to be unique among echinostomes, especially in the digitation of its tegumental spines, the distribution of sensory papillae and by severe folds of the tegument.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.106-111
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• 2005

For breeding of a new rootstock for eggplant production, somatic hybrids between two species, Solanum integrifolium and S. sanitwongsei were obtained through protoplast fusion. The former species has been commonly used for rootstock for eggplant production in Japan. Eggplants on these rootstocks are more productive than ungrafted plants, but are susceptible to bacterial wilt caused Ralstonia solanacearum. While the latter species is resistant, the growth of eggplants on this rootstock is rather slow and low yield. Protoplast of both species were isolated from cotyledons, and inactivated with iodoacetamide or UV-irradiation, then fused electrically. The fused products were then cultured. Regenerated plantlets were then transplanted on soil then maintained in a green house. The plants were classified into four groups. Those in the first group showed morphological characters intermediate of the parentalspecies. The plants bore fruit with viable seeds. The plants showed a chromosome number of 2n=48, the sum of those of the parental species, and are suggested to be symmetric fusion products. While plants in the other groupswas less vigorous and showed chromosome number 2n= 68 to 72 suggesting asymmetric fusion products by genomic in situ hybridization(GISH). Isozyme pattern of shikimate dehydrogenase (SKDH; EC 1.1.1.25), isocitrate dehydrogenase (IDH; EC 1.1.1.41) and phosphoglucomutase (PGM; EC 2.7.5.1) showed that 24 regenerated plants in three groups were somatic hybrids. Analysis of random amplified polymorphic DNA (RAPD) showed that 43 S. integrifolium-specific and 57 S. sanitwongsei-specific bands were all found in 24 plants. Both somatic hybrids and its S1 plants were found to be resistant to bacterial wilt, and eggplant grafted these plants using for rootstocks were more productive than grafted mother plants. Now, S1 progenies are used for commercial eggplant production in Osaka Prefecture.

• Journal of Soil and Groundwater Environment
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• v.21 no.3
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• pp.64-81
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• 2016

To analyze the influence of various groundwater flow rates (specific discharge) on BHE system with balanced and unbalanced energy loads under assuming same initial temperature (15℃) of ground and groundwater, numerical modeling using FEFLOW was used for this study. When groundwater flow is increased from 1 × 10⁻⁷ to 4 × 10⁻⁷m/s under balanced energy load, the performance of BHE system is improved about 26.7% in summer and 22.7% at winter time in a single BHE case as well as about 12.0~18.6% in summer and 7.6~8.7% in winter time depending on the number of boreholes in the grid, their array type, and bore hole separation in multiple BHE system case. In other words, the performance of BHE system is improved due to lower avT in summer and higher avT in winter time when groundwater flow becomes larger. On the contrary it is decreased owing to higher avT in summer and lower avT in winter time when the numbers of BHEs in an array are increased, Geothermal plume created at down-gradient area by groundwater flow is relatively small in balanced load condition while quite large in unbalanced load condition. Groundwater flow enhances in general the thermal efficiency by transferring heat away from the BHEs. Therefore it is highly required to obtain and to use adequate informations on hydrogeologic characterristics (K, S, hydraulic gradient, seasonal variation of groundwater temperature and water level) along with integrating groundwater flow and also hydrogeothermal properties (thermal conductivity, seasonal variation of ground temperatures etc.) of the relevant area for achieving the optimal design of BHE system.

• Journal of the Korean GEO-environmental Society
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• v.4 no.2
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• pp.5-13
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• 2003

The domestic design method for the shaft resistance of drilled shafts into a bedrock is based on the empirical method, where the uniaxial compressive strength of rock specimen is utilized for calculation of the shaft resistance. This method has uncertainties in prediction of capacity of drilled shafts and result in uneconomic engineering design. Recently a new improved design method was suggested, which reflects important factors that affect the strength of pile sockets. Socket roughness is one of the significant factors influencing the shaft resistance of drilled shaft socketed into rock. In this paper roughness information for the shaft resistance design of socket pile was suggested on the basis of statistical analysis of data measured from wall surface in the bore holes of drilled shafts.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.2
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• pp.113-121
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• 1994

Since two oil shocks in 1970s, all of engine makers have persevered in their efforts to reduce specific fuel consumption and to increase engine power rate as much as possible in marine diesel engines. As a result, the maximum pressure in cylinders of these engines has been continuously increased. It causes direct axial vibration. The axial stiffness of crank shaft is low compared to old types of engine models by increasing the stroke/bore ratio and its major critical speed might occur within engine operation range. An axial damper, therefore, needs to be installed in order to reduce the axial vibration amplitude of the crankshaft. Usually the main critical speed of axial vibration for the propulsion shafting system with a 4-8 cylinder engine exists near the maximum continuous revolution(MCR). In this case, when the damping coefficient of the damper is increased within the allowance of the structural strength, its stiffness coefficient is also increased. Therefore, the main critical speed of axial vibration can be moved beyond the MCR. It has the same function as a conventional detuner. However, in the case of a 9-12 cylinder engine, the main critical speed of axial vibration for the propulsion shafting system exists below the MCR and thus the critical speed cannot be moved beyond the MCR by using an axial damper. In this case, the damping coefficient of an axial damper should be adjusted by considering the range of engine revolution, the location and vibration amplitude of the critical speed, the fore and aft vibration of the hull super structure. It needs to clarify the dynamic characteristics of the axial vibration damper to control the axial vibration appropriately. Therefore authors suggest the calculation method to analyse the dynamic characteristics of axial vibration damper. To confirm the calculation method proposed in this paper, it is applied to the propulsion shafting system of the actual ships and satisfactory results are obtained.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.769-774
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• 2013

Turbine blades and disc, which are one of the most important rotating parts of a gas turbine engine, are required to have highly efficient performance in order to minimize the total life cycle costs. Owing to these requirements, these components are exposed to severe conditions such as extreme turbine inlet temperatures, high compression ratios, and high speeds. To evaluate the structural integrity of a turbine disc under these conditions, material modeling and finite element analysis techniques are essential; furthermore, shape optimization is necessary for determining the optimal solution. This study aims to generate 2D finite element models of an axisymmetry model and a sector one and to perform thermal-structural coupled-field analysis and contact analysis. Structurally vulnerable areas such as the disc bore and disc-blade interface region are analyzed by a parametric study. Finally, an improved design is provided based on the results, and the necessity of elaborate shape optimization is confirmed.