• Journal of Korean Society of Steel Construction
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• v.28 no.2
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• pp.75-83
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• 2016

Existing tubes for concrete filled tubular structure are made through welding of four plates irrespective, but the production performance is poor and special welding technique is needed to weld the internal or through diaphragm. Accordingly, We developed a welded built-up square steel tube having a welding lines and a stiffeners at location out of stress concentration. The welded built-up square steel tube occurred a interference with stiffeners at the internal or through diaphragm, therefore researches of a external diaphragm for welded built-up square CFT column connections are needed for the purpose of avoidance of a interfere with stiffeners. In this study we suggest a design formulation for external diaphragm of the welded built-up square CFT external diaphragm connections. Four specimens were manufactured for a experimental test, then we analyzed the behaviors of the specimens.

• Journal of Korean Society of Steel Construction
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• v.26 no.4
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• pp.311-322
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• 2014

Concrete filled tubular structure should be installed diaphragms for moment connection. However internal and through diaphragm should be special welded when connected to column tube. The other hand, that has become increase of stress concentration and extend of construction error. Therefore, In this study the seismic performance of beam to column connections with External Diaphragms and implement cycle loading experiment. we had evaluated seismic performance with mentioned experiment which is concrete filled or not, variable shapes, to be welded or not of diaphragm. Also, formula of strength of external diaphragm was analyzed and looked into adequacy with regard to formula of tension strength.

• Applied Microscopy
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• v.15 no.1
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• pp.71-85
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• 1985

The ultrastructure on the dorsal vessel of 5-day-old cabbage butterfly, Pieris rapae L., was carried out using the transmission and scanning electron microscope. The results are as follows. 1) The aorta. The aorta is simple tubular type and consists of the inner and outer membrane of the myocardium and thick myocardium is located between them. However the inner membrane with $0.26{\mu}m$ thickness and outer membrane with $0.08{\mu}m$ are composed of fibrous materials, the former is composed of low and high densed fibrous materials and the latter appears homogeneous layer. The myocardium consists of typical striated muscles. The sarcomere with $1.6{\mu}m$ length and in cross section, each thick filaments are surrounded by $7{\sim}8$ thin filaments. The intercalated disc is joining the end of the two muscle cells, desmosomes and septate junctions are appeared between the neighboring muscle cells. 2) The heart. The heart composing of myocardium enclosed by its inner and outer membrane as the aorta has a series of well formed segmental chamber. The arrangement of myofilaments, cell adhensions and membrane elements are observed as same as at the aorta. The inner membrane of the heart is deeply invaginated into the myocardium than the outer membrane and a lot of well developed mitochondria with rod shape are aggregated in the folds. The longitudinally and transversely oriented tubule system formed by invagnation of the sarcolemma into the muscle bundle is built up dyad with the sarcoplasmic reticulum as the aorta. The slit is formed by deeply invagination of the inner membrane of myocadium toward the muscle layer and then the inner and outer membrane of myocardium are fused. Therefore, the ostium is formed between the myocardium and situated at the lateral side of the myocardium.

• Applied Microscopy
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• v.41 no.4
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• pp.257-263
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• 2011

The microanatomy and ultrastructure of the digestive diverticulum of Mytilus galloprovincialis were described using light and electron microscopy. The digestive diverticulum of tawny color was surrounded the stomach and connected to stomach by a primary duct. Digestive diverticulum is composed of numerous digestive tubules. The epithelial layer of a simple digestive tubule, which is simple, is composed of basophilic cells and digestive cells. Basophilic cells are columnar in shape, and has a well-developed endoplasmic reticula, tubular mitochondria, Golgi complex and membrane-bounded granules of high electron density in the cytoplasm. Whereas digestive cells are columnar in shape, with development of microvilli and cilia on the free surface. Pinocytic vasicles, active lysosomes and numerous mitochondria were observed in the apical cytoplasm of digestive cells. The results of this study suggest that basophilic cell and digestive cell of the digestive tubule are specialized in the extracellular and intracellular digestion, respectively.

• Steel and Composite Structures
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• v.19 no.5
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• pp.1115-1144
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• 2015

Current climate conditions along with advances in technology make further design and verification methods for structural strength and reliability of wind turbine towers imperative. Along with the growing interest for "green" energy, the wind energy sector has been developed tremendously the past decades. To this end, the improvement of wind turbine towers in terms of structural detailing and performance result in more efficient, durable and robust structures that facilitate their wider application, thus leading to energy harvesting increase. The wind tower industry is set to expand to greater heights than before and tapered steel towers with a circular cross-section are widely used as more capable of carrying heavier loads. The present study focuses on the improvement of the structural response of steel wind turbine towers, by means of internal stiffening. A thorough investigation of the contribution of stiffening rings to the overall structural behavior of the tower is being carried out. These stiffening rings are placed along the tower height to reduce local buckling phenomena, thus increasing the buckling strength of steel wind energy towers and leading the structure to a behavior closer to the one provided by the beam theory. Additionally to ring stiffeners, vertical stiffening schemes are studied to eliminate the presence of short wavelength buckles due to bending. For the purposes of this research, finite element analysis is applied in order to describe and predict in an accurate way the structural response of a model tower stiffened by internal stiffeners. Moreover, a parametric study is being performed in order to investigate the effect of the stiffeners' number to the functionality of the aforementioned stiffening systems and the improved structural behavior of the overall wind converter.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.6
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• pp.21-29
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• 2014

This paper deals with the bonding characteristic of grouted joint connections of monopile support structures for offshore wind power facilities. For the integration of pile connection of wind power supporting structure, fiber reinforced high performance cementeous grout was developed and the ultimate compressive strength of it is 125MPa and the direct tensile strength is 7.5 MPa at 7 days. To assess the bond strength of grout filled in pile connection, small scaled direct bond tests under axially loaded was performed and analyzed according the existing guidelines. The fiber volume fraction (0%, 0.5% and 0.9%), aspect ratio of fiber (60 and 80) and the ratio of height to spacing of shear key (0.013 and 0.056) were adopted as the experimental variables. From the test results, the maximum bond strength among the all specimens was 30.8MPa and the bond strength of grouted connection was affected by the ratio of height to spacing of shear key than the fiber volume fraction.

• Journal of Navigation and Port Research
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• v.27 no.1
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• pp.63-70
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• 2003

If semi-rigid connections are used for superstructures of very large floating structures (VLFS), the number of rigid connections can be reduced and more economical construction will be possible. In this study, considering service load and wave load in VLFS, the applicability of mixed use of rigid and semi-rigid connections have been studied using three types of connections for a four-bay eight-story frame. Three types of connections are used; top and seat-angle connections with double web-angle(TSD), extended end plate connections, steel tubular column with square external-diaphragm connections. ABAQUS(Finite element analysis program) is used for conducting second order elastic analysis.

• Applied Microscopy
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• v.34 no.2
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• pp.83-93
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• 2004

Integumentary structures of the rockfish, Sebastiscus tertius were examined by means of the light and transmission electron microscopy. Stratified epidermal layer consists of supporting cells, unicellular glands, granular cells and mitochondria-rich cells. The epidermal layer could be classified into superficial, intermediate and basal layer by morphology and structure of the supporting cells. Mucous cells of unicellular gland were observed in the superficial and intermediate layer of the epidermis. The mucous materials were identified as acidic and carboxylated mucosubstance by histochemical methods. Club cell has well-developed central vacuole, rough endoplasmic reticula and Golgi complex in the cytoplasm. Granular cells were observed in the superficial layer and contained numerous granules of high electron density. Mitochondria-rich cells are characterized by well-developed microfilaments in cortex and numerous tubular mitochondria in medullar cytoplasm. Three types of pigment cells in the dermal layer could be distinguished with electron density of cytoplasmic inclusions.

• Parasites, Hosts and Diseases
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• v.44 no.2 s.138
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• pp.151-156
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• 2006

A case of breast sparganosis was confirmed by surgical excision of a worm (fragmented into 5 pieces) in a 59-year-old Korean woman suffering from a palpable mass in the left breast. Mammography and ultrasonography characteristically revealed the presence of several well-defined, isodense and hypoechoic tubular masses, in the upper quadrant of the left breast, each mass consisting of a continuous cord- or worm-like structure. During surgery, a long segment of an actively moving sparganum of Spirometra sp. and 4 small fragments of the same worm, giving a total length of 20.3 cm, were extracted from the upper outer quadrant of the left breast and the axillary region. The infection source remains unclear, because the patient denied ingesting any snake or frog meat or drinking untreated water.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.3
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• pp.229-235
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• 2021

Objective: In this study, the effects of Lactobacillus acidophilus on testosterone (TES), follicle-stimulating hormone (FSH), luteinizing hormone (LH), androgen-binding protein (ABP), factor-associated apoptosis (FAS), and total cholesterol (TC), as well as histopathological changes, were investigated in male rats fed a high-cholesterol diet. Methods: The study included three groups. The control (C) group was fed standard-diet for 8 weeks. The hypercholesterolemia (HC) group was fed a 2% cholesterol-diet for 8 weeks. The therapeutic group (HCL) was fed a 2% cholesterol-diet for 8 weeks and administered L. acidophilus for the last 4 weeks. FSH, TES, and FAS levels in testicular tissue were determined using an enzyme-linked immunosorbent assay (ELISA), while another sample was examined histopathologically. LH and ABP levels were determined using ELISA, and serum TC levels were assessed via an autoanalyzer. Results: In the HC group, the TC levels were significantly higher and the LH levels were lower (p<0.05) than in the C group. The ABP levels were lower (p>0.05). In the HCL group, the LH and ABP levels were higher (p>0.05) and the TC level significantly lower (p<0.05) than in the HC group. The TES and FSH levels were lower, and the FAS levels were higher, in the HC than in the C group (p<0.05). In the HCL group, levels of all three resembled control levels. Histologically, in the testicular tissue of the HC group, the cells in the tubular wall exhibited atrophy, vacuolization, and reduced wall structure integrity. However, in the HCL group, these deteriorations were largely reversed. Conclusion: Supplementary dietary administration of an L. acidophilus to hypercholesterolemic male rats positively impacted testicular tissue and male fertility hormone levels.