• Title/Summary/Keyword: Surface examination

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Flexural strength properties of MoSi2 based composites (MoSi2 복합재료의 굽힘강도 특성)

  • Lee, Sang-Pill;Lee, Hyun-Uk;Lee, Jin-Kyung;Bae, Dong-Su
    • Journal of Ocean Engineering and Technology
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    • v.25 no.4
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    • pp.66-71
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    • 2011
  • The flexural strength of $MoSi_2$ based composites reinforced with Nb sheets has been investigated, based on the detailed examination of their microstructure and fractured surface. Both sintered density and porosity of Nb/$MoSi_2$ composites were also examined. Nb/$MoSi_2$ composites were fabricated by different conditions such as temperature, applied pressure and its holding time, using a hot-press device. The volume fraction of Nb sheet in this composite system was fixed as 10%. The characterization of Nb/$MoSi_2$ composites were investigated by means of optical microscopy, scanning electron microscope and three point bending test. Nb/$MoSi_2$ composites represented a dense morphology at the interfacial region, accompanying the creation of two types of reaction layer by the chemical reaction of Nb and $MoSi_2$. Nb/$MoSi_2$ composites possessed an excellent density at the fabricating temperature of $1350^{\circ}C$, corresponded to about 95% of theoretical density. The flexural strength of Nb/$MoSi_2$ romposites were greatly affected by the pressure holding time at the same fabricating temperature, owing to the large suppression of porosity in the microstructure. Especially, Nb/$MoSi_2$ composites represented a good flexural strength of about 310 MPa at the fabricating condition of $1350^{\circ}C$, 30MPa and 60min, accompanying the pseudo-ductile fracture behavior by the deformation of Nb sheet and the interfacial delamination.

Foot and Shoe Survey in Adult Patients with Diabetes Mellitus (성인 당뇨병 환자의 족부와 신발에 대한 조사)

  • Lee, Woo-Chun
    • Journal of Korean Foot and Ankle Society
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    • v.8 no.2
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    • pp.153-156
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    • 2004
  • Purpose: To investigate the status of foot, preventive foot care and appropriateness of shoe size in patients with diabetes. Materials and Methods: One hundred and sixty-five patients who visited endocrinology clinic due to clinically proven diabetes mellitus were studied. Average age was 59.3 years (range, 36-90 years) and average duration of diabetes was $9.6{\pm}8.2$ years. Patients were questioned about their basic educational level and their foot and ankle problems. Physical examination of the foot was done including sensation testing of four areas of plantar surface with the 5.07 monofilament. Both feet and shoes were measured for width, length and the height of toes and toebox. Shoes were defined as properly fitting the foot if it is 5mm wider than the foot, and $20{\pm}30\;mm$ longer than the foot, and the height of toebox is more than 5mm higher than the height of the toes. Results: 48.5 percent of the patients were educated about how to select an appropriate shoewear. 47.3 percent of the patients had symptoms of neuropathy and 42.4 percent of patients were unable to feel the monofilament in at least one area. 25.5 percent of the patients had appropriate shoes in length, 63.6 percent of the patients in width, and 72.7 percent of the patients in the height of toebox. Conclusion: This study suggets that more patients needs to be educated about foot care and appropriate shoes which have adequate height of toebox as well as the length and width.

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A Study on the 'Transparency' of Office Lobbies (오피스 로비 공간에 나타난 '투명성'의 표현에 관한 연구)

  • Lee, Hyo-Chang;Ha, Mi-Kyoung
    • Proceedings of the Korean Institute of Interior Design Conference
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    • 2006.05a
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    • pp.113-118
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    • 2006
  • The lobby is the space that contributes the most to conveying the first impression of an enterprise or company that is occupying a building, and enhances the quality of the urban or business environment around an office building. Transparency is the biggest change in architecture since the modern age began, and it is the most important element of the lobby expression methods. Therefore this study was an attempt to understand the expression method of transparency which is expressed in the lobby space of office buildings, and used documentary survey and field survey to analyze it. In the examination of the theoretical background of transparency to make a specific study purpose, and based on an on-the-spot probe document, an attempt was made to grasp the expression method of Visual Transparency and Phenomenal Transparency. The data collected during this investigation was studied and a correlation coefficient. A summary of the findings of this study is as follows: 1) Transparent materials does not appear often in floors. But Phenomenal Transparency material is used in the floor. 2) During the survey it was discovered that Visual Transparency was often used in the walls of each investigated building. Phenomenal Transparency materials are found less in walls than in the floors of lobbies. 3) The expression methods that appeared the most in ceilings among the Visual Transparent expression methods. In the case of Phenomenal Transparency, the highest distribution is seen in ceilings. 4) The result of the analyzation of the correlation coefficient of Visual Transparency and Phenomenal Transparency is as follows: Expression method: There is more than one expression method of transparency, 'Open Sight', 'Light Material' and 'Surface Material' methods were introduced in case of the introduction of 'Transparent Material' among Visual Transparency in office building lobby space planning. If the 'Superimposed Space' method is introduced, then the 'Ambiguous Border' or 'Dual Sight' methods are introduced.

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Evolution of suspended sediment patterns in the East China and Yellow Seas

  • Ahn, Yu-Hwan;Shanmugam, Palanisamy;Gallegosi, Sonia
    • Journal of the korean society of oceanography
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    • v.39 no.1
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    • pp.26-34
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    • 2004
  • The evolution of intricate and striking patterns of suspended sediments (SS), which are created by certain physical dynamics in the East China and Yellow Seas, has been investigated using satellite ocean color imageries and vertical profiles of particle attenuation and backscattering coefficients. The structure of these patterns can reveal a great deal about the process underlying their formation. Sea surface temperature (SST) analyzed from the Advanced Very High Resolution Radiometer (AVHRR) thermal infrared data were used to elucidate the physical factors responsible for the evolution of suspended sediment patterns in the East China Sea. The concomitant patterns of suspended sediments were tracked from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) ocean color data. The detailed examination about these patterns gave birth to the definition of the evolution of suspended sediments (SS) into four stages: (1) Youth or Infant stage, (2) Younger stage, (3) Mature stage, and (4) Old stage. We describe about the three directional forces of the tidal currents, ocean warm currents and estuarine circulations that lead to occurrence of various stages of the evolution of suspended sediments that increase turbidity at high levels through out the water column of the inner and outer shelf areas during September to April. The occurrence of these four stages could be repeatedly observed. In contrast, vertical profiles of the particle attenuation ($c_{p}$) and backscattering ($b_{bp}$) coefficients displayed obvious patterns of the propagation of suspended sediment plume from the southwestern coastal sea that leads to eventual collision with the massive sediment plume originating from the Yangtze banks of the East China Sea.

A Proposal for Standardization of Tongue Diagnosis Based on Diagnostic Criteria of Tongue Coating Thickness (설진의 표준화를 위한 제언 : 설태 후박의 진단기준을 중심으로)

  • Son, Ji-Hee;Kim, Jin-Sung;Park, Jae-Woo;Ryu, Bong-Ha
    • The Journal of Internal Korean Medicine
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    • v.33 no.1
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    • pp.1-13
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    • 2012
  • Background : In oriental medicine, the status of the tongue is an important indicator to diagnose the condition of one's health, such as physiological and the clinicopathological changes of internal organs. A tongue diagnosis is not only convenient but also non-invasive, and therefore widely used in Oriental medicine. However, the tongue diagnosis is greatly affected by examination circumstances, patient's posture, and doctor's diagnosis criteria. Objectives : This study was designed to assure the necessity for standardization of tongue diagnosis based on diagnostic criteria of tongue coating thickness (TCT). Methods : Thirty tongue photographs were acquired and analyzed by digital tongue diagnosis system (DTDS) which measured the percentage of TCT on the tongue surface. Fifteen oriental medical doctors evaluated TCT in 30 photographs. Afterward, the 15 assessors were trained for diagnostic criteria of TCT and evaluated the photographs again. The intraclass correlation coefficient (ICC) was used to obtain the agreement rate among the 15 assessors and the agreement rate between assessors' TCT scores and DTDS values. Results : The agreement rate among the 15 assessors after training was higher than before training. The agreement rate between assessors' TCT scores and DTDS values after training was also higher than before training. Furthermore, the difference of the agreement rate between before and after training was significant (p<0.05). Conclusions : The standardization of diagnostic criteria of TCT increased the agreement rate among the assessors and the agreement rate between assessors' TCT scores and DTDS values. Therefore, the standardization of diagnostic criteria is expected to contribute to the objectification and quantification of the tongue diagnosis system.

Friction Characteristics of Aluminized Polyester Fabric under Dry - and Water- Lubricated Conditions

  • Byun, JaeYoung;Okechukwu, Nicholas Nnaemeka;Lee, Eunsuk;Park, JinGyu;Choi, WonSik
    • Tribology and Lubricants
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    • v.35 no.6
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    • pp.396-402
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    • 2019
  • Materials made from plastics are increasingly utilized in constructing greenhouses and setting up shield structures. Polyester fabrics have a wide range of use in horticulture and other fields of agriculture. They are utilized as a greenhouse cover and also help in combating intense climate variation in the field. Over time, these fabrics may experience friction against other surfaces. Owing to this, the surface framework of the material degenerates. This study examines the frictional characteristics of aluminized polyester fabric in both dry- and water-lubricated environments under changing applied loads and sliding speeds. Friction experiments are performed at room temperature by employing a pin on a disk. The experiments reveal that the friction coefficient decreases with increase in applied load in both dry sliding and water-lubricated environment. However, the friction coefficient decreases more under the water-lubricated setting than in the dry state. At the maximum applied load, the highest friction coefficient is discovered in the dry state with a range of 0.282 to 0.237, whereas a friction coefficient of 0.229 to 0.189 is observed in the water-lubricated state. Additionally, it is observed that the friction coefficient increases with an increase in sliding speed under both experimental environments. The examination of specimen surfaces reveals that the abrasion is minor in the water-lubricated setting compared with that in the dry state.

Gastroepiploic Artery Preservation with Glycerol as a Training Model for Microvascular Anastomosis (미세혈관문합술의 연습 모델로서 글리세롤 처리된 위대망동맥의 활용)

  • Park, Chan Young;Chang, Hak;Chung, Jin Haeng;Heo, Eun Ju;Minn, Kyung Won;Yoo, Moon Won;Yang, Han Kwang
    • Archives of Plastic Surgery
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    • v.35 no.5
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    • pp.626-629
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    • 2008
  • Purpose: We investigate the possibility of vessel preservation with glycerol and evaluate the potential of preserved gastroepiploic artery as a tool for the microsurgical practice. Methods: In 5 early gastric cancer patients, IRB(No. C-0603-040-170), we gained gastroepiploic artery specimens(5 segments, about 10 cm) after gastrectomy. Each segment was rinsed in a normal saline and subsequently placed in a bottle, containing 50 mL anhydrous glycerol (87%). The bottles were refrigerated at $4^{\circ}C$, the longest preservation time being 5 months. Results: At first glance, no fragmentation was detected and the surface of vessel seemed mild sclerotic. In histological examination, vascular structures remained intact though preservation with glycerol led to a mild atrophy of the smooth muscle in the tunica media. Especially, we found out the elastic fibers and endothelial lining of the intima were preserved until 5 months. Adequate status for using microsurgical practice was also maintained and leakage test was performed successfully with gentian violet ink. Conclusion: Based on the results obtained in this study, the gastroepiploic artery preservation with glycerol as a training model for microvascular anastomosis is a technically very simple procedure and useful for the novice microsurgeon.

Metallic Structure of Iron Relics of Chosun Dynasty Excavated from Gangsun Tower, Chengpyeong Temple (청평사 강선루 출토 조선시대 철제유물의 금속조직에 대하여)

  • Kim, S. K.;Lee, C. H.
    • Journal of Conservation Science
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    • v.17 s.17
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    • pp.57-64
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    • 2005
  • In the course of examining the micro structure of Iron chisel and Iron arrowhead, a relics of the 16th or 17th of Chosun Dynasty unearthed at near Gangsun-tower, Chengpyeong temple. Collected un-eroded samples from the relics were looked into the metallic structure through optical metallography. Non-metallic inclusions were-analysed by SEM and EDS. The micro structure examination and SEM-SDS analysis revealed that Iron chisel and Iron arrowhead had been produced from the sponge iron close to pure iron made by low temperature reducing in a solid and then the surface carbon content was increased by carburizing treatment. It was also found that Iron chisel had been hardened through the repetitive processes of quench hardening and heat treatment, after increasing carbon content to a certain level. Up to now, there have been a number of studies in the domestic academia which were studied mainly on the structure of metallic relics in the period of the Three Kingdoms or before. Although this research was limited in type and number of the relics, it turned out to be interesting in that it revealed the 16th or 17th century way of processing iron, even in fragments. It is thought to be fruitful that iron had been made even in the Chosun Dynasty from the sponge iron.

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Inflammation, Oxidative Stress and L-Fucose as Indispensable Participants in Schistosomiasis-Associated Colonic Dysplasia

  • Soliman, Nema Ali;Keshk, Walaa Arafa;Shoheib, Zeinab Salah;Ashour, Dalia Salah;Shamloula, Maha Moustafa
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.3
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    • pp.1125-1131
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    • 2014
  • Background: Schistosomiasis is a parasitic disease causing chronic ill health in humans with a serious consequences for socio-economic development in tropical and subtropical regions. There is also evidence linking Schistosoma mansoni to colonic carcinoma occurrence. The aim of this study was to evaluate some inflammatory and oxidative stress biomarkers, as well as L-fucose as linkers between intestinal schistosomiasis and colonic dysplasia development in mice. Materials and Methods: This study was conducted upon 80 mice that were divided the control group (10 non infected mice) and infected group which was subdivided into 7 sub-groups (10 mice each) according to the time of sacrifaction in the post infection (p.i.) period, 10 mice being sacrificed every two weeks from 6 weeks p.i. to 18 weeks p.i. Tumor necrosis factor alpha (TNF-${\alpha}$), inducible nitric oxide synthase (iNOS), and pentraxin 3 (PTX3) levels were estimated by immunoassay. The L-fucose level, and thioredoxin reductase (TrxR) and lactate dehydrogenase (LDH) activities were also evaluated in colonic tissue. Results: The current study revealed statistically significant elevation in the studied biochemical markers especially at 16 and 18 weeks p.i. The results were confirmed by histopathological examination that revealed atypical architectural and cytological changes in the form of epithelial surface serration and nuclear hyper-chromatizia at 14, 16 and 18 weeks p.i. Conclusions: inflammation, oxidative stress and L-fucose together may form an important link between Schistosomal mansoni infection and colonic dysplasia and they can be new tools for prediction of colonic dysplasia development in experimental schistosomiasis.

Spatial Dose Distribution for Diagnostic X-ray Examination within X-ray Room using the MCNPX Program (MCNPX 프로그램을 통한 일반 X선 검사 시 검사실 내 공간선량분포)

  • Lee, Dong-yeon;Lee, Jin-soo
    • The Journal of the Korea Contents Association
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    • v.15 no.11
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    • pp.298-306
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    • 2015
  • This study is the material of the additional filter(Cu, Ni, CaWO4, Gd+Ba) being used when the diagnosis X-ray was varied to evaluate the spatial dose distribution accordingly. And it suggest to find a suitable material. Experiments using MCNPX program based on the Monte Carlo simulation method was carried out by selecting the chest and abdomen taken. As a result, each material per dose, the average scatter dose is approximately 62%, 100 cm radius of the point of the simulated body surface exposure dose and 50 cm radius centered on the point average about 47%. It is determined that an Al material is currently available in accordance with the result to be replaced by Cu, Ni material is sufficient. With just the thickness due to the difference in the atomic number and density adjusted to be about one-tenth of the Al it will be suitable.