• 한국재료학회지
• /
• 제34권1호
• /
• pp.12-20
• /
• 2024

This study successfully prepared high-porosity aluminosilicate fibrous porous ceramics through vacuum suction filtration using aluminosilicate fiber as the primary raw material and glass powder as binder, with the appropriate incorporation of glass fiber. The effects of the composition of raw materials and sintering process on the structure and properties of the material were studied. The results show that when the content of glass powder reached 20 wt% and the samples were sintered at the temperature of 1,000 ℃, strong bonds were formed between the binder phase and fibers, resulting in a compressive strength of 0.63 MPa. When the sintering temperatures were increased from 1,000 ℃ to 1,200, the open porosity of the samples decreased from 89.08 % to 82.38 %, while the linear shrinkage increased from 1.13 % to 10.17 %. Meanwhile, during the sintering process, a large amount of cristobalite and mullite were precipitated from the aluminosilicate fibers, which reduced the performance of the aluminosilicate fibers and hindered the comprehensive improvement in sample performance. Based on these conditions, after adding 30 wt% glass fiber and being sintered at 1,000 ℃, the sample exhibited higher compressive strength (1.34 MPa), higher open porosity (89.13 %), and lower linear shrinkage (5.26 %). The aluminosilicate fibrous porous ceramic samples exhibited excellent permeability performance due to their high porosity and interconnected three-dimensional pore structures. When the samples were filtered at a flow rate of 150 mL/min, the measured pressure drop and permeability were 0.56 KPa and 0.77 × 10^-6 m² respectively.

• Anatomy and Cell Biology
• /
• 제57권1호
• /
• pp.25-30
• /
• 2024

The aim of this study was to identify the anatomical feature of retaining ligament and fat compartment on the lower eyelid and infraorbital region using a histological method, and to investigate clear definitions for them which could be used generally in the clinical area. Eighteen specimens from eight fresh Korean cadavers were stained with Masson trichrome or hematoxylin and eosin. The ligamentous and fascial fibrous tissue were clearly identified. The ligamentous fibrous tissue which traversed in the superficial and deep fat layer was skin ligament and orbicularis retaining ligament (ORL). The fascial fibrous tissue enclosed the orbicularis oculi muscle (OOc) and circumferencial adipose tissue. Based on the ligamentous and fascial structure, three fat compartments, septal, suborbicularis oculi and infraorbital fat compartment, could be identified. The OOc attached to orbital rim and dermis by ORL and skin ligament, and the muscle fascicle and fat fascicle provided the connection point to the ORL and skin ligament as enclosing all muscle and fat tissue. The combination of the force made by the skin ligament in the lower eyelid and ORL may decide the level and form of the infraorbital grooves.

• 자원환경지질
• /
• 제49권1호
• /
• pp.1-11
• /
• 2016

사문석군 광물과 관련된 국내 선행 연구에 따르면 일반적으로 크리소타일(chrysotile)이 섬유상으로 산출되는 것으로 알려져 있다. 하지만 국외에서 섬유상 안티고라이트(antigorite)의 산출이 보고되었으며 이로 인한 인체의 유해성에 대한 연구가 현재 진행되고 있다. 따라서, 이 연구에서는 국내 홍성과 가평지역의 사문암 내에서 섬유상으로 산출되는 사문석군 광물의 종류와 광물학적 및 화학적 특성을 XRD, SEM-EDS, PLM, EPMA 분석을 통해 확인하고, 이를 통해 사문석군 광물의 산출양상 및 형성과정을 규명하고자 하였다. 연구지역인 홍성은 각섬석 편암이 부분적으로 사문암화 또는 활석화 되어 있으며, 가평은 석회질 편암이 사문석화 작용을 받아 석회암 및 각섬암 내 사문암대를 형성하고 있다. 연구 결과, 홍성에서는 크리소타일과 안티고라이트가 섬유상으로, 가평에서는 크리소타일이 섬유상으로 산출되는 것으로 확인되었다. 분산염색법을 이용한 편광현미경 분석 결과, 크리소타일은 섬유 길이방향($n{\parallel}$)에서 자주색(magenta), 섬유 지름방향($n{\perp}$)에서 파란색(blue)의 분산염색색상을 보였고, 안티고라이트는 섬유 길이방향($n{\parallel}$)에서 진한 노란색-자주색(gold to golden magenta), 섬유 지름방향($n{\perp}$)에서 blue magenta의 분산염색색상을 나타냈다. 또한 박편관찰 및 SEM 분석을 통해 판상의 사문석 또는 암석 내 1차 광물이 열수변질작용을 받아 섬유상의 광물을 형성한 것으로 판단된다. EPMA mapping 분석 결과, Mg 성분은 크리소타일이 안티고라이트보다 상대적으로 높았으며 Si와 O 성분은 안티고라이트가 크리소타일보다 높은 것으로 확인되었다. 하지만 두 광물의 화학성분 차이를 정확히 알기 위해서는 많은 시료의 통계적인 분석 값이 필요할 것으로 생각된다. 이러한 결과를 통해 섬유상의 안티고라이트(antigorite)는 X-선 회절 패턴과 형태적 특성이 크리소타일(chrysotile)과 비슷하여 혼동될 수 있으나, 서로 다른 분산염색색상을 나타내므로 분산염색법을 이용한 편광현미경 분석을 통해 두 광물의 구별이 가능한 것으로 확인되었다.

• Journal of Korean Neurosurgical Society
• /
• 제46권1호
• /
• pp.77-80
• /
• 2009

Orbital solitary fibrous tumor (SFT) is a rare tumor originating from the mesenchyme. We describe the clinical presentations, radiological and operative findings, and pathological features of a patient with orbital SFT. The patient was a 46-year-old female who presented with progressive proptosis advanced for 20 months. On ophthalmological examination, no visual impairment was detected, but left eye was found to be obviously protruded on exophthalmometry. Orbital magnetic resonance imaging showed a 2.5 ${\times}$ 2 ${\times}$ 2 cm, intensely enhanced mass in the left orbit, which compressed the eyeball forward and the optic nerve downward. The patient underwent frontal craniotomy with superior orbitotomy and gross total resection was performed for the tumor. The histopathological diagnosis including immunohistochemistry was a SFT. After the surgery, proptosis was markedly relieved without visual impairment. Although orbital SFT is extremely rare, it should be considered in the differential diagnosis of orbital tumors. Clinical presentations such as painless proptosis and CD34 immunoreactivity play a significant role in differentiating orbital SFT from other spindle-cell neoplasms of the orbit.

• Computers and Concrete
• /
• 제17권3호
• /
• pp.323-336
• /
• 2016

Although the self-compacting concrete (SCC) offers several practical and economic benefits and quality improvement in concrete constructions, in comparison with conventionally vibrated concretes confronts with autogenously chemical and drying shrinkage which causes the formation of different cracks and creates different problems in concrete structures. Using different fibers in the mix design and implementation of fibrous concrete, the problem can be solved by connecting cracks and micro cracks together and postponing the propagation of them. In this study an experimental investigation using response surface methodology (RSM) based on full factorial design has been undertaken in order to model and evaluate the polypropylene fiber effect on the fibrous self-compacting concrete and curing time, fiber percentage and fiber amount have been considered as input variables. Compressive strength has been measured and calculated as the output response to achieve a mathematical relationship between input variables. To evaluate the proposed model analysis of variance at a confidence level of 95% has been applied and finally optimum compressive strength predicted. After analyzing the data, it was found that the presented mathematical model is in very good agreement with experimental results. The overall results of the experiments confirm the validity of the proposed model and this model can be used to predict the compressive strength of fibrous self-compacting concrete.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제31권3호
• /
• pp.262-266
• /
• 2009

Solitary fibrous tumor (SFT) is a neoplasm that arises most commonly in pleura. Although SFT occasionally occurs in extrapleural locations, the incidence in the oral cavity is rare. SFT is benign in almost cases and surgical excision is the effective treatment. SFT occurred in the left cheek of a 60-year-old man presented with a painless submucosal mass. The tumor was surgically removed. Immunohistochemical study showed that tumoral cells were negative for SMA, S-100, but positive for Bcl-2, CD34. SFT is easily over-diagnosed if strict criteria are not carefully applied, and strict diagnostic criteria are necessary to avoid confusion of SFT with more aggressive lesions.

• Imaging Science in Dentistry
• /
• 제46권4호
• /
• pp.259-265
• /
• 2016

Fibrous dysplasia (FD) is an uncommon skeletal disorder in which normal bone is replaced by abnormal fibro-osseous tissue. Mainly, FD is found in children, and by adulthood it usually becomes quiescent. Our case showed FD of more than 14-year duration in the left maxilla. Our evaluation was that growth ceased in adulthood and had achieved the static stage. Because FD cases in elderly patients are rarely reported, we hereby present a monostotic FD case in a 65-year-old female. We presented sequential radiographic images and scintigraphic images of this case, and combined them with a literature review that emphasized the progression of the disease.

• 콘크리트학회논문집
• /
• 제11권6호
• /
• pp.35-46
• /
• 1999

The steel fiber reinforced concrete may affect substantially to the tension stiffening at post cracking behavior. Even if several tension stiffening models exist, they are for plain and normal strength concrete. Thus, the development of tension stiffening models for steel fibrous high strength RC members are necessary at this time when steel fiber reinforced and high strength concretes are common in use. This paper presents tension stiffening effects from experimental results on direct tension members with the main variables such as concrete strength, concrete cover depth, steel fiber quantity and aspect ratio. The comparison of existing models against experimental results indicated that linear reduced model closely estimated the test results at normal strength level but overestimated at high strength level. Discontinuity stress reduced model underestimated at both strength levels. These existing models were not valid enough in applying at steel fibrous high strength concrete because they couldn't consider the concrete strength nor section area. Thus, new tension stiffening models for high strength and steel fiber reinforced concrete were proposed from the analysis of experimental results, considering concrete strength, rebar diameter, concrete cover depth, and steel fiber reinforcement.

• 대한골관절종양학회지
• /
• 제5권3호
• /
• pp.190-193
• /
• 1999

Benign fibrous histiocytoma is characteristically composed of fibroblastic and histiocytic cells. Most commonly, this tumor occurs in the dermis and superficial subcutis, but it is uncommon in the knee. We experienced a case of deep benign fibrohistiocytoma in a 38-year-old woman who complained of palpable tender mass on the medial aspect of the right knee. MR imaging findings included a well-delineated oval mass with low signal intensity on T1-weighted and high-signal intensity of T2-weighted images, as well as a marked peripheral contrast enhancement. Histopathologically, the lesion contained a mixture of fibroblastic and histiocytic cells that were often arranged in a cartwheel or storiform pattern and accompanied by varying numbers of inflammatory cells, foam cells, and siderophages. After surgical removal of the lesion, no recurrence was observed.

• 대한세포병리학회지
• /
• 제9권1호
• /
• pp.99-104
• /
• 1998

Anaplastic large cell lymphoma(ALCL) is an uncommon type of non-Hodgkin's lymphoma(NHL) populated with anaplastic, often bizarre cells that express CD30 (Ki-1) antigen. The unusual histologic and cytologic features may cause confusion with other neoplasms, such as poorly differentiated carcinoma, melanoma, Hodgkin's disease, or true histiocytic lymphoma. Although the cytologic features of ALCL have been well described, there are few reports about cytologic findings of the sarcomatold variant of ALCL. We experienced a case of fine needle aspiration(FNA) cytologic findings of ALCL which mimicks malignant fibrous histiocytoma. FNA cytology of chest wall mass in a 62-year-old female with a history of peripheral T-cell lymphoma(Lennert lymphoma) revealed a heterogeneous population of single cells and poorly cohesive cells with large, pleomorphic nuclei and spindle cells gathering around vascular structures within an inflammatory background. Additional features of the neoplastic cells were eccentric, multilobated nuclei with occasional 'wreath-like' configuration; abundant cytoplasm with vacuolization; and prominent nucleoli. The cytologic features suggested sarcoma, especially malignant fibrous histiocytoma. The diagnosis was made retrospectively with an aid of immunocytochemical staining.