• Applied Microscopy
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• 제29권3호
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• pp.343-351
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• 1999

The structures of the fertilized egg envelope from three species, three-spot gourami (Trichogaster trichopterus), pearl gourami (Trichogaster leeri) and marble gourami (Trichogaster trichopterus trichopterus) belong to Belontiidae were observed, utilizing light, scanning and transmission electron microscopes. In all three species, the fertilized eggs were the colorless, transparent, spherical, adhesive and pelagic type. A large oil droplet was located in vitelline membrane of the fertilized egg. The egg envelopes have a single micropyle, which is thought to the pathway of sperm in the area of the animal pole. Specially, the micropyle of three-spot gourami was similar to that of marble gourami which is subspecies of three-spot gourami. An outer surface of the fertilized egg envelope was arranged by grooves in all three species. The fertilized egg envelopes consists of two distinct layers; an adhesive outer layer and an inner layer with high electron density. In conclusion, the morphological similarity of the fertilized egg, micropyle, outer surface and transverse section of the fertilized e9g envelope seems to be an indication of the Belontiidae.

• Bulletin of the Society of Naval Architects of Korea
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• 제26권1호
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• pp.46-62
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• 1989

This paper presents the results of full-scale structural measurements of 4,800 unit pure car carriers "HYUNDAI NO.103" and "HYUNDAI NO.105" on one voyage respectively for each ship, especially in order to investigate the local strength of partial bulkhead above free-board deck. With the measured data, the short-term frequency analyses have been performed. The results show that the wave-induced stresses follow, on the whole, well the Rayleigh distribution. In addition, it has been found from the measured data that transverse local stresses at bulkhead section have a very close relation with the acceleration in athwartship direction. Finally, the long-term analysis has been attempted by using the following two statistical distributions mainly in order to estimate the maximum stress amplitude at the corners of partial bulkhead. 1) Exponential distribution of cycles of stress amplitude 2) Double exponential distribution of extreme values of stress amplitude for each short-term analysis The results of these two cases show a good agreement with each other. For example, the estimated maximum stress amplitude for 10 years at port-side corner of Fr. 132 partial bulkhead is $2125kg/cm^2$ for the first case and $2170kg/cm^2$ for the second case just based on the measured data.

• Journal of the Earthquake Engineering Society of Korea
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• 제11권3호
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• pp.23-31
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• 2007

Fast bridge construction has been increasingly needed according to the changed construction environment. This paper deals with quasi-static tests on precast piers for bridge substructures. One of the most crucial aspect of the design of precast prestressed concrete bridge piers is the seismic performance. Seven precast pier elements were fabricated. The amount of prestressing bars, the prestressing force, and the location and number of the joint between segments were the main test parameters. Test results showed that the introduced axial prestress made the restoration of the deformation under small lateral displacement and minor damage. However, there was no effect of the prestress when the plastic hinge region was damaged severely due to large lateral displacement. Judging from the observed damage, the design of the joints in precast piers should be done for the first joint between the foundation and the pier segment. The amount of the necessary prestressing steel may be designed to satisfy the P-M diagram according to the service loads, not by having the same steel ratio as normal RC bridge piers. In order to satisfy the current required displacement ductility, it is necessary to have the same amount of the transverse reinforcements as RC piers. As the steel ratio increases, the energy absorption capacity increases. The number of joints showed a little influence on the energy absorption capacity.

• Journal of Korean Society of Steel Construction
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• 제20권1호
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• pp.105-119
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• 2008

In steel deck bridges suffering directly on wheel load according to the number of serviced years, the occurrence of fatigue cracks increases in structural details, which includes the cross section parts of the longitudinal rib and transversal rib, and so on. Through the control method for these fatigue cracks the increased thickness of the steel deck plate or the application of retrofit detail to the inside of the longitudinal rib was observed to be effective. This study suggests structural details for the retrofitted and non-retrofitted longitudinal rib. The target details in this study are the connection parts of the lo ngitudinal and transversal rib, and the slit parts of transverse rib where fatigue cracks were frequently reported in previous studies. In the analyses, detailed structural analyses were performed as parameters, which include the shape, change of size and attached position. From the results the stress reduction in the target details was observed to be larger in the retroffited details. Also, the improvement of fatigue strength is more effective in the retrofitted details with the vertical rib than the bulkhead plate.

• Korean Journal of Food Science and Technology
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• 제52권6호
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• pp.655-660
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• 2020

High amylose corn starch and dextrin (acid-treated at 30, 40 and 50℃ denominated as Dextrin30, Dextrin40 and Dextrin50) were added to non-fried instant noodles. X-ray diffraction pattern, water absorption, cooking loss, microstructure, and textural properties of non-fried instant noodles were investigated. The addition of high amylose corn starch/dextrin induced a slight peak intensity at 20o in the X-ray pattern indicating the insignificant formation of amylose-lipid complex. Non-fried instant noodles including high amylose corn starch/dextrin showed lower water absorption than the control. Dense microstructure in transverse section of noodles was observed in non-fried instant noodles including high amylose corn starch/dextrin except Dextrin50. Also, the addition of high amylose corn starch/dextrin induced low tensile strength, high firmness, and high stickiness. However, non-fried instant noodles containing Dextrin50 showed a loose microstructure and high cooking loss (3.98%), which might be associated with the textural properties such as the lowest tensile strength (0.17 N), lowest increase in firmness (46.77 N) and highest stickiness (18.43 N).

• Journal of the Korea institute for structural maintenance and inspection
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• 제25권1호
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• pp.7-15
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• 2021

In this study, we developed Void Plywood Slab (VPS) that improved the shape of existing hollow materials. Its performance was evaluated through one-way flexural and one-way shear tests using the developed VPS. As a result of the one-way flexural performance tests of VPS, the yield load value for FPS series(longitudinal direction specimens with hollow materials) was approximately 97.5% compared to FPS-00(without hollow materials) specimen. The tests showed that the yield load was not much different. In addition, FNS series(transverse direction specimens with hollow materials) also represented about 97% of FPS-00 specimen. The one-way flexural performance was shown to have little impact from void materials. Therefore, it is confirmed that the presented system is applicable to the VPS to the slab design. The results of the one-way shear performance tests of VPS showed that it was about 92% compared to the SS-00(without hollow materials) specimen. These results were somewhat insufficient for the SS-00 specimen. Shear strength equation is expressed as the sum of shear force by concrete and shear force by reinforcement. However, in the case of void slab, it is believed that the concrete section has been deleted by the void material. However, the strength of the structure applied to the shear design, as with the flexural design, is also applied to the design based on the yield load value.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제28권6D호
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• pp.809-817
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• 2008

This paper deals with the development of ViscoElastic Continuum Damage Finite Element Program (VECD-FEP++) and its verification with the results from both field and laboratory accelerated pavement tests. Damage characteristics of asphalt concrete mixture have been defined by Schapery's work potential theory, and uniaxial constant crosshead rate tests were carried out to be used for damage model implementation. VECD-FEP++ predictions were compared with strain responses (longitudinal and transverse strains) under moving wheel loads running at different constant speeds. To this end, an asphalt pavement section (A5) of Korea Expressway Corporation Test Road (KECTR) instrumented with strain gauges were loaded with a dump truck. Also, a series of accelerated pavement fatigue tests have been conducted at pavement sections surfaced with four asphalt concrete mixtures (Dense-graded, SBS, Terpolymer, CR-TB). Planar strain responses were in good agreement with field measurements at base layers, whereas strains at both surface and intermediate layers were found different from simulation results due to the complexity of tire-road contact pressures. Finally, fatigue characteristics of four asphalt mixtures were reasonably described with VECD-FEP++.

• Journal of the Computational Structural Engineering Institute of Korea
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• 제37권4호
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• pp.251-258
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• 2024

This study investigated the effect of bearing aging on the seismic response of a three-span continuous concrete girder bridge with pot bearings installed. The pot bearings were modeled as elastic springs in the longitudinal, transverse, and vertical directions of the bridge to reflect the stiffness of fixed and movable supports. The effect of bearing aging on the seismic response of the bridge was examined by considering two factors: a decrease in the horizontal stiffness of the fixed bearings and an increase in the horizontal stiffness of the movable bearings. The finite element model of the three-span continuous girder bridge was validated by comparing its numerical natural frequencies with the designed natural frequencies. Using artificial ground motions that conform to the design response spectrum specified by the KDS bridge seismic design code, the seismic responses of the bridge's girders and bearings were calculated, considering the bearing stiffness variation due to aging. The results of a numerical analysis revealed that a decrease in the horizontal stiffness of the fixed bearings led to an increase in the absolute maximum relative displacement of the bearings during an earthquake. This increases the risk of the mortar block that supports the bearing cracking and the anchor bolt breaking. However, an increase in the horizontal stiffness of the movable bearings due to aging decreased the absolute maximum shear on the fixed bearings. Despite the shear reduction in the fixed bearings, the aging of the pot bearings change could cause additional tensile bending stress in the girder section above the free bearings, which could lead to unexpected structural damage to the continuous bridge during an earthquake.

• The Journal of the Korean bone and joint tumor society
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• 제7권1호
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• pp.28-35
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• 2001

Purpose : Authors investigated the efficiency of preoperative MRI in suspicious glomus tumor and the clinical outcomes after marginal excision. Materials and Methods : In 10 cases of glomus tumors in the fingers, authors retrospectively analyzed the clinical data, including previous trauma, treatment history, preoperative symptoms, physical examination, plain radiography, MRI (9 cases), pathological findings and postoperative complications. Results : The patients had pain in 10 cases, tenderness in 9 cases, cold sensitivity in 3 cases and edema in one case. MRI showed low signal (3 cases) or iso-signal (5) intensity on T1 weighted image, high signal intensity (8) on T2 weighted image, and all the lesions were enhanced in gadolinium enhancement images. The exact locations of glomus tumors were median in 6 cases, lateral in 5, lateral fold in 2 and pulp in 3 in transverse section and nail bed in 5 cases and nail matrix in 5 in sagittal section. Marginal excision was performed by lateral approach in one case and transungual in 9 cases. Histologically, all 10 cases were composed of solid sheets of round cells interrupted by thin-walled blood vessels. Most of clinical symptoms were disappeared in all cases after operation. Nail deformity was found in one case, which was originated from nail matrix, however, there was no recurrence. Summary : Clinical symptom was the most impotant factor in diagnosis of glomus tumor in the fingers. However, preoperative MRIs were helpful in patients, who had obscure pain or prolonged clinical symptoms with suspicious glomus tumors. Preoperative MRI might be one of the most useful tools for establishing the exact diagnosis and detecting the location of glomus tumors, in spite of the relatively high expenses.

• Journal of the Korean Society of Hazard Mitigation
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• 제8권5호
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• pp.137-145
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• 2008

In this study, to reduce the flood damage caused by flood discharge exceeding project flood, the primary technology was applied to determining the optimal location and size for underground sluiceway. The Jungrang Stream was selected for this study because the stream was overflowed and the embankment section of the stream was destroyed owing to localized torrential rainfall in 1998 and 2001. Considering 200-year frequency storm, the inlets of the underground discharge channel were located at Seoul City limits, the confluence of Danghyun Stream, Wolgye 1-gyo, and the confluence of Mukdong Stream. The outlets were located at the estuary of Jungrang Stream and rightbank of Banpo Bridge in Han River. The transverse discharge according to the variation of overflow depth at the inlet of underground discharge channel was estimated and the effect of inundation reduction was analyzed. To examine the appropriate scale of the underground discharge channel, the 8 operation methods for the management of outlet discharge were compared considering four rules (only storage, the constant discharge rate, the constant discharge volume, and the mixture of the constant discharge rate and discharge volume). As a result, the effect of inundation reduction was most significantly improved when the inlet was located at the confluence of Danghyun Stream. The appropriate size of underground sluiceway for 200-year frequency storm was studied, and as a result, the appropriate diameters of the underground discharge channel were 12 m in case of only storage(Rule D), 9m in 50% of discharge(Rule E), 8 m in constant discharge volume(Rule F), and 7 m in mixture method(Rule G). This investigation process can be applied to design the underground discharge channel when the inundation damage is significant in coastal area due to embankment overflow. The underground discharge channel in Jungrang Stream can also be used as an underground road to link Seoul City to Uijeongbu City during dry season.