• Computers and Concrete
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• v.2 no.3
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• pp.239-248
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• 2005

The article presents the results of examination of the fractal dimension D of concrete specimen fracture surfaces obtained in fracture toughness tests. The concretes were made from three different types of coarse aggregate: gravel, dolomite and basalt aggregate. Ordinary concretes (C40) and high-performance concretes (HPC) were subjected to testing after 7, 14, 28 and 90 days of curing, respectively. In fracture toughness and compressive tests, different behaviours of concretes were found, depending on the type of aggregate and class of concrete (C40, HPC). A significant increase in the strength parameters tested occurred also after a period of 28 days (up to the $90^{th}$ day of curing) and was particularly large for concretes C40. Fractal examinations performed on fracture replicas showed that the fractal dimension D was diverse, depending on the coarse aggregate type and concrete class being, however, statistically constant after 7 and 14 days for respective concretes during curing. The fractal dimension D was the greater, the worse strength properties were possessed by the concrete. A cross-grain crack propagation occurred in that case, due to weak cohesion forces at the coarse aggregate/mortar interface. A similar effect was observed for C40 and HPC made from the same aggregate. A greater dimension D was exhibited by concretes C40, in which case the fracture was easier to form compared with high-performance concretes, where, as a result of high aggregate/mortar cohesion forces, the crack propagation was of inter-granular type, and the resulted fracture was flatter.

• Applied Microscopy
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• v.19 no.1
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• pp.59-69
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• 1989

Ultrastructure of the secretory portion of the small ampullate gland in the orb web spider, Nephila clavata, has been investigated using the electron microscope. The secretory portion of this gland comprise two different regions which are a S-shaped storage sac and a long, convoluted tail. By the internal textures of the secretory granules, the sac is subdivided into two regions ; the proximal region near the tail and the distal region near the duct. Commonly single layered connectives cover the basal portion of the sac epithelium, and apical portion of the epithelial cells is occupied by the thick cuticles. Within the epithelial cells of both the proximal and distal region, several types of the secretory granules surrounded by a limiting membrane and had characteristic crystalloid are scattered throughout the cytoplasm. The granular size and its electron densities are not coincide with each other according to the maturation level of the granules. The wall of the tail is composed of single layer of columnar epithelial cells, and their nuclei are found at the basal portion of the cells. Dissimilar to the epithelial cells of the sac, apical cuticles are not found at this portion. In the cytoplasm of these cells, numerous secretory granules, synthesized from the rough endoplasmic reticula commonly and had fine fibrous materials, are found. At the cell surface bordering the lumen, microvilli are seen, arid along the cellular boundaries specialized septate junctions and desmosomes appeared.

• The Korean Journal of Cytopathology
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• v.7 no.1
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• pp.31-37
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• 1996

It is well known that fine needle aspiration biopsy(FNAB) is very useful and has a high accuracy rate in the diagnosis of renal neoplasms. Although there is some indecision to perform the FNAB for a rare possibility of tumor seeding along the biopsy needle tract, it tends to be used increasingly. As in the cytologic diagnosis of metastatic lesion through-out the body, renal cell carcinoma should nearly always be considered in the differential diagnosis, the precise understanding of cytologic features of renal cell carcinoma with various cell types and architectural patterns is necessarily required. In this report, we present three cases of primary renal cell tumors, two of renal cell carcinomas and one of oncocytoma, preponderantly emphasizing the cytologic differential points in the FNAB specimen.

• Journal of Yeungnam Medical Science
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• v.34 no.2
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• pp.298-302
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• 2017

Glandular papilloma of the lung is one of three histologic types of solitary endobronchial papillomas. It is known as an uncommon benign neoplasm. No malignant glandular papillomas have been reported. Herein, the first case of granular papilloma with malignant transformation is reported. A 74-year-old man with huge right lung mass extended upper and lower lobe was admitted to the hospital complaining of progressive cough and dyspnea. An open lung biopsy was performed. Microscopically, the tumor showed papillary growth pattern with thick fibrovascular cores. The stroma of the fibrovascular cores shown the infiltration of lymphoplasmacytic cells and proliferation of capillaries. The epithelial cells surrounding the papillary fronds were cilliated columnar cells with focal cellar atypia, and frequent mitoses. Suspicious pleural invasion foci were identified. The Ki-67 labeling index was about 24.3% and p53 labeling index was about 31.7%. Glandular papilloma is known as a benign neoplasm, which is lack of atypia and mitosis. In present case, there were several indications of malignant transformation, such as cellular atypia, frequent mitosis, architectural distortion, and pleural invasion. Pathologists must be aware that glandular papilloma can have a changes of malignant transformation. Further studies about disease behavior and molecular characteristics are needed.

• Journal of the Korean Society for Heat Treatment
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• v.16 no.3
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• pp.127-133
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• 2003

The effect of chemical composition on the microstructural change and tensile property in TRIP-assisted steels with different chemical composition was investigated by using SEM, TEM, XRD and UTM. As a result of microscopic observation, the morphology of retained austenite could be identified as two types; a granular type in a steel containing higher Si and a film type in a steel having higher C. For the case of higher C-containing steel with a tensile strength of 860 MPa and a total elongation of 38%, film-typed retained austenite could be observed between lath bainitic ferrite. Actually, metastable retained austenite was a requisite for the good formability, which means that chemical composition plays a significant role in the microstructure and tensile property of TRIP-assisted steels. With respect to tensile property, the steels containing suitable Si and Mn, respectively, showed a typical TRIP effect in stress-strain curve, while a steel containing higher Mn content exhibited the similar behavior shown in dual phase steel.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.3
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• pp.106-113
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• 2007

The effect of chemical composition on the microstructural change and tensile property in TRIP-assisted steels with different chemical composition was investigated by using SEM, TEM, XRD and UTM. As a result of microscopic observation, the morphology of retained austenite could be identified as two types : a granular type in a steel containing higher sillicon and a film type in a steel having higher carbon. For the case of higher carbon-containing steel with a tensile strength of 860 MPa and a total elongation of 38%, film-typed retained austenite could be observed between lath bainitic ferrite. Actually, metastable retained austenite was a requisite for the good formability, which means that chemical composition plays a significant role in the microstructure and tensile property of TRIP-assisted steels. With respect to tensile property, the steels containing suitable silicon and manganese, respectively, showed a typical TRIP effect in stress-strain curve, while a steel containing higher manganese content exhibited the assimilar behavior shown in dual phase steel.

• Geomechanics and Engineering
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• v.6 no.3
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• pp.235-248
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• 2014

Population increase and economic developments can lead to construction as well as demolition of infrastructures such as buildings, bridges, roads, etc resulting in used concrete as a primary waste product. Recycling of waste concrete to obtain the recycled concrete aggregates (RCA) for base and/or sub-base materials in road construction is a foremost application to be promoted to gain economical and sustainability benefits. As the mortar, bricks, glass and reclaimed asphalt pavement (RAP) present as constituents in RCA, it exhibits inconsistent properties and performance. In this study, six different types of RCA samples were subjected classification tests such as particle size distribution, plasticity, compaction test, unconfined compressive strength (UCS) and California bearing ratio (CBR) tests. Results were compared with those of the standard road materials used in Queensland, Australia. It was found that material type 'RM1-100/RM3-0' and 'RM1-80/RM3-20' samples are in the margin of the minimum required specifications of base materials used for high volume unbound granular roads while others are lower than that the minimum requirement.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.11 no.2
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• pp.33-42
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• 2003

In this paper, we propose an enhancement of the ultrasonic image for non-destructive inspection of aircraft composite materials. The ultrasonic images are corrupted by a speckle noise which has the characteristic of granular pattern noise and is in all types of coherent imaging systems, the signal independent and multiplicative noise. In this paper, we derive a filter, called the AWLF(Adaptive Window Log Filter), from the nature of the speckle. The filter is made of the MEAN Filter in the edge region and Log Filter in the flat or noise region. To make a distinction between edge and flat region, we calculate the inclination around the local window instead of computing the local statistics of pixels such as local mean ${\bar{M}}$ and standard deviation ${\sigma}_s$. According to the obtained region, edge region is performed by the mean filter and flat region by the Log filter. Performance of the proposed filter is evaluated by the Enhanced Factor$(F_e)$ and the Speckle Index(SI).

• Applied Microscopy
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• v.26 no.1
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• pp.47-57
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• 1996

This study analysed the transport properties of bladder mucosa known as the typical system of 'tight epithelia' by using TEM observation with both rapid freeze-fracture electron microscopy and thin-section method and mainly analysed the cellular characteristics of turtle bladder epithelial cells. The bladder epithelium, like other tight epithelia, consists of a heterogenous population of cells. The majority of the mucosal cells are the granular cells and may function primarily in the process of active $Na^+$ reabsorption in turtle bladder. The remaining two types of cells are rich in mitochondria and is believed to be res-ponsible for a single major transport system, namely, $H^+$ transport by A-type of cell and urinary $HCO_{3}^-$ secretion by B-type of cell. As viewed in freeze-fracture electron micrograph, the tight junctions form a continuous tight seal around the epithelial cells, thus restricting diffusion in tight epithelia. In addition, the apical surface membranes have a population of rod-shaped intramembranous particles (IMPs). It is believed that these IMPs probably represent the components of the proton pump. However, it is likely that these characteristics of the apical transporter remain to be clarified in tight epithelial cells.

• Journal of the Korean Society for Heat Treatment
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• v.16 no.4
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• pp.205-210
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• 2003

Various types of high strength steel sheets were usually used for improving the automobile safety and fuel efficiency by reducing the vehicle weight. The present study aimed to develop the TRIP (transformation induced plasticity) aided high-strength low carbon steel sheets by using a reverse transformation process. The 0.1C-4~8Mn steels were reverse-transformed by slow heating to intercritical temperature region and then furnace cooled to the room temperature. Granular type retained austenite was observed in 4Mn steel and lath type retained austenite was also observed in 6~8Mn steel. The results show that the 6Mn steel under reverse transformed at $625^{\circ}C$ for 6 hrs has maximum elongation up to 39%. The optimum strength-elongation combination was 3,888 ($kg/mm^2{\times}%$) when the 8Mn steel was reverse transformed at $625^{\circ}C$ for 12 h.