• Design & Manufacturing
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• 제11권3호
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• pp.8-12
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• 2017

In general, metallic bio-materials is more widely used in solid tissue like bone or tooth than flexible tissue such as skin or muscle. Especially, Cobalt Chrome Molybdenum(Co-Cr-Mo), which is used in tooth surgery, has a great corrosion resistance. Because this bio-material is non-toxic in human body, and has a bio-compatibility that the vital reaction is not occurred with tissue in body. However the chemical reaction is occurred by fatal matter that deteriorate the property of material surface in conventional polishing, and it can affect to fatal disease in human body or decrease the material properties such as hardness, yield strength or bio-compatibility. This surface in poor condition can cause development of corrosion or bacteria. In this study, MR fluid polishing is used to minimize the scratch, pit or surface flaws generated in conventional polishing. Surface roughness is measured according to the polishing condition to obtain fine surface condition.

• Journal of the Korean Wood Science and Technology
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• 제42권5호
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• pp.499-509
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• 2014

Wood filler is a porous and anisotropic material having different size, shape, and aspect ratio. The use of wood fillers such as wood particle, wood flour, and wood pulp in wood plastic composites (WPCs) are growing rapidly because these wood fillers give improved strength and stiffness to WPCs. However, the wood fillers have originally poor compatibility with plastic matrix affecting the mechanical properties of WPCs. Therefore, to improve compatibility between wood and plastic, numbers of physical and chemical treatments were investigated. While the various treatments led to improved performances in WPC industries using petroleum-based plastics, full biodegradation is still issues due to increased environmental concerns. Hence, bio-based plastics such as polylactide and polyhydroxybutyrate having biodegradable characteristics are being applied to WPCs, but relatively expensive prices of existing bio-based plastics prevent further uses. As conventional processing methods, extrusion, injection, and compression moldings have been used in WPC industries, but to apply WPCs to engineered or structural places, new processing methods should be developed. As one system, co-extrusion technique was introduced to WPCs and the co-extruded WPCs having core-shell structures make the extended applications of WPCs possible.

• The Plant Pathology Journal
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• 제17권5호
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• pp.276-280
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• 2001

Fusarium isolates of Gibberella fujikuroi species complex were obtained from sorghum grown in five provinces of Korea in 1996 and 1997. These isolates were characterized based on their mating behavior, mycotoxin production, and vegetative compatibility. Only three mating populations (A, D, and F) were recovered from a total of 155 isolates examined. The relative frequency of the mating populations was significantly different: F was predominant (80%), while D and A were observed at low frequencies of 9% and 3%, respectively. Female fertile isolates were more common within F (44 our of 124) than D (2 out of 14), while none of the five A isolates were female fertile. The inbreeding effective population sizes ($\textrm{N}_e$)for mating type and male/hermaphrodite ratios in mating populations A and D produced significant amounts of fumonisins, while F isolates produced none or only traces of fumonisin B$_1$. In contrast. F isolates produced higher amounts of moniliformin (average of 3,820 ppm) than A and D isolates (averages of 77 and 1,819 ppm, respectively). Fifty-one isolates were tested for vegetative compatibility using nitrogen non-utilization mutants of each isolate, and 44 vegetative compatibility groups (VCGs) were identified. A single VC type (VC1) was found in all of the five A isolates examined. Six of the D isolates examined consisted of three VC types: two for VC2, two for VC3, and the rest for VC4. All of the F isolates tested were incompatible in every combination and , thus, each constituted a unique VCG.

• 한국환경과학회지
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• 제22권10호
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• pp.1287-1294
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• 2013

In this study, thermoplastic starch (TPS), cross-linked starch (CS), and cross-linked starch modified with glycerol (CTPS) were prepared, and the mechanical properties of the compatibilized low-density polyethylene (LDPE) blends (LDPE/TPS, LDPE/CS, and LDPE/CTPS) were investigated and compared with those of uncompatibilized LDPE/TPS, LDPE/CS, and LDPE/CTPS blends. Maleic-anhydride-grafted polyethylene was used as the compatibilizer. The enhanced tensile strength and elongation at break for the compatibilized LDPE/modified starch blends are a result of the improved compatibility between LDPE and the modified starch, which was confirmed by torque measurements and scanning electron microscopy.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
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• pp.140-143
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• 2004

Compatibility of polymeric materials governs their suitability for nearly all potential applications. An aspect of compatibility that is frequently important for fluoropolymers is their ability to isolate fluids by serving as a barrier to mass transport. This property is commonly expressed as permeability. In ideal cases, both solubility and diffusivity are constant at any given temperature and so the permeability is also a constant.(omitted)

• 한국산학기술학회논문지
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• 제15권5호
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• pp.3351-3356
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• 2014

최근, 플라스틱 남용으로 인해 바이오매스 기반 물질에 대한 연구의 중요성이 증가하고 있는 추세이다. Cellulose acetate butyrate (CAB)는 생분해성의 성질 때문에 재생이 가능하여 잠재성을 가지고 있는 고분자이다. Poly(ethylene-co-isosorbide terephthalate) (PEIT)는 아이소소바이드 모노머로부터 유래된 바이오매스 기반의 고분자이다. 본 연구에서는 다양한 분야에 적용되고 있지만 열안정성이 낮은 CAB에 내열성이 높은 PEIT를 도입하여 용액 블렌딩 방법을 통해 CAB/PEIT 블렌드를 제조하였다. 블렌드의 상용성을 판단하기 위해 모폴로지와 유리전이온도의 거동을 FE-SEM, DMA를 사용하여 분석하였다. TGA 결과는 CAB/PEIT 75/50, 50/50 조성에서 향상된 열적 안정성을 나타내었으며 XRD에서 새로운 결정 구조는 관찰되지 않았다. 결과적으로 CAB/PEIT solution blends는 모든 조성에서 좋은 상용성을 가짐을 확인하였다.

• 대한산업공학회지
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• 제30권1호
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• pp.50-57
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• 2004

The aim of this study is to collect driver's psychophysiological signal under various road condition and to select and quantify psychophysiological variables for diagnosis of road-driver compatibility. A 4x4 vehicle with measuring devices was developed to collect driver's psychophysiological signal and collected driver's psychophysiological signal under various road conditions. The collected data were analyzed by the temporal pattern of signal overtime. Thirteen bio-signals with consistent pattern were selected and quantified in terms of slope and amplitude of the signal. These quantified values could be used as a part of tool to diagnose the road-driver compatibility.

• 대한치과보철학회:학술대회논문집
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• 대한치과보철학회 2006년도 춘계학술대회 및 제3차 한일 공동 국제 학술대회
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• pp.120-120
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• 2006

• 대한산업공학회지
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• 제30권1호
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• pp.44-49
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• 2004

The aim of this study is to compare the methods in analyzing bio-signals representing measure driver's psychophysiological staus. This study has considered three approaches: first, the deterministic approach calculating the mean and standard deviation of bio-signal, second, probabilistic approach converting driver's bio-signal values to probability density function and identifying individual state relative to overall distribution, and third, diagnostic approach identifying the pattern change of signal over certain period of time. For evaluation of analysis methods, driver's bio-signal was collected under various road conditions, and three analysis approaches were applied respectively. In result, the deterministic approach was found to be simple to use, but generated a large variability of bio-signal. The probabilistic approach provide a relative status of individual driver among overall population, but too much affected by temporal variability of individual driver. The diagnostic approach seemed to reasonably find driver's psychophysiological change over certain period of time, but still needs to develop quantification method of the bio-signal.

• 한국전기전자재료학회논문지
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• 제34권6호
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• pp.487-494
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• 2021

Piezoelectric generators use direct piezoelectric effects that convert mechanical energy into electrical energy. Many studies were attempted to fabricate piezoelectric generators using piezoelectrics such as ZnO, PZT, PVDF. However, these various inorganic/organic piezoelectric materials are not suitable for bio-implantable devices due to problems such as brittleness, toxicity, bio-incompatibility, bio-degradation. Thus, in this paper, piezoelectric generators were prepared using a silk fibroin film which is bio-compatible by dip-coating method. The silk fibroin films are a mixed state of silk I and silk II having stable β-sheet type structures and shows the d₃₃ value of 8~10 pC/N. There was a difference in output voltages according to the thickness. The silk fibroin generators, coated 10 times and 20 times, revealed the power density of 16.07 μW/cm² and 35.31 μW/cm² using pushing tester, respectively. The silk fibroin generators are sensitive to various pressure levels, which may arise from body motions such as finger tapping, foot pressing, wrist shaking, etc. The silk fibroin piezoelectric generators with bio-compatibility shows the applicability as a low-power implantable piezoelectric generator, healthcare monitoring service, and biotherapy devices.