• Title/Summary/Keyword: 기계적 변형률

Search Result 257, Processing Time 0.026 seconds

A Study on the Encapsulation of Cosmetic Emulsion Using Microfluidics (Microfluidics를 이용한 화장품 에멀젼 캡슐레이션에 대한 연구)

  • Jeong, Nam-Gyun;Jin, Hong-Jong
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.22 no.1
    • /
    • pp.81-86
    • /
    • 2021
  • The cosmetic industry is technology-intensive in the field of fine chemistry and continues to grow globally. The functional aspects have been mainly emphasized in the past to increase the market share in these cosmetics industries. Recently, however, efforts have been made to attract the attention of consumers to the visual effects as well as the excellent performance of cosmetics at home and abroad. Accordingly, cosmetic manufacturers are trying various technologies that encapsulate the cosmetic emulsion and modify the shape, color, and texture of the emulsion capsule. The basic and easiest method of encapsulating emulsion is dropping the emulsion through the nozzle from emulsion storage. On the other hand, the existing method of encapsulating emulsion has a limit in reducing the size of the capsule. In this study, the limit was shown by theory and numerical analysis method, and the emulsion encapsulation phenomena occurring in the micro-channel were studied to apply microfluidics as an alternative.

Application of Ultrasonic Nano Crystal Surface Modification into Nitinol Stent Wire to Improve Mechanical Characteristics (나이티놀 스텐트 와이어의 기계적 특성 향상을 위한 초음파 나노표면 개질 처리에 대한 연구)

  • Kim, Sang-Ho;Suh, Tae-Suk;Lee, Chang-Soon;Park, In-Gyu;Cho, In-Sik;Pyoun, Young-Shik;Kim, Seong-Hyeon
    • Progress in Medical Physics
    • /
    • v.20 no.2
    • /
    • pp.80-87
    • /
    • 2009
  • Phase transformation, superelastic characteristics and variation of surface residual stress were studied for Nitinol shape memory alloy through application of UNSM technology, and life extension methods of stent were also studied by using elastic resilience and corrosion resistance. Nitinol wire of ${\phi}1.778$ mm showed similar surface roughness before and after UNSM treatment, but drawing traces and micro defects were all removed by UNSM treatment. It also changed the surface residual stress from tensile to compressive values, and XRD result showed less intensive austenite peak and clear martensite and additional R-phase peaks after UNSM treatment. Fatigue resistance could be greatly improved through removal of surface defects and rearrangement of surface residual stress from tensile to compressive state, and development of surface modification system to improve not only bio-compatability but also resistance to corrosion and wear will make it possible to develop vascular stent which can be used for circulating system diseases which run first cause of death of recent Koreans.

  • PDF

Nondestructive Interfacial Evaluation and fiber fracture Source Location of Single-Fiber/Epoxy Composite using Micromechanical Technique and Acoustic Emission (음향방출과 미세역학적시험법을 이용한 단일섬유강화 에폭시 복합재료의 비파지적 섬유파단 위치표정 및 계면물성 평가)

  • Park, Joung-Man;Kong, Jin-Woo;Kim, Dae-Sik;Yoon, Dong-Jin
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.23 no.5
    • /
    • pp.418-428
    • /
    • 2003
  • Fiber fracture is one of the dominant failure phenomena affecting the total mechanical Performance of the composites. Fiber fracture locations were measured through the conventional optical microscope and the nondestructive acoustic emission (AE) technique and then were compared together as a function of the epoxy matrix modulus and the fiber surface treatment by the electrodeposition method (ED). Interfacial shear strength (IFSS) was measured using tensile fragmentation test in combination of AE method. ED treatment of the fiber surface enlarged the number of fiber fracture locations in comparison to the untreated case. The number of fiber fracture events measured by the AE method was less than optically obtained one. However, fiber fracture locations determined by AE detection corresponded with those by optical observation with small errors. The source location of fiber breaks by AE analysis could be a nondestructive, valuable method to measure interfacial shear strength (IFSS) of matrix in non-, semi- and/or transparent polymer composites.

Application of Ultrafast Laser for Micro-packaging and Germanium Surface Processing (초고속레이저 기반 마이크로 패키징 및 게르마늄 표면 공정 기술 개발)

  • Jeoung, S.C.;Yahng, J.S.
    • Journal of the Korean Vacuum Society
    • /
    • v.16 no.1
    • /
    • pp.74-78
    • /
    • 2007
  • Much interests has been drawn for noble micro-engineering processes for the continuous size reduction on bulk materials from the field of micro-electronics with much downsized IC chips. A traditional microprocessing based on mechanical blade as well as a relatively long pulsed laser usually influence the physico-chemical properties of intact materials when the techniques are applied to process materials with a spatial resolution less than 10 microns. Meanwhile, ultrafast laser pulses are known to exhibit a very small heat-affect zone(HAE) compared to the traditional laser processing and to be applicable for the new functional materials with high performance in optical and electrical properties. In this report, we will review in brief the recent research works on the enhancement of micro-cutting speed of thin silicon wafer as well as the formation of Ge nanostructures based on ultrafast laser pulses.

Evaluation of Fracture Toughness of Copper Thin Films by Combining Numerical Analyses and Experimental Tests (해석과 실험을 결합한 구리 박막의 파괴인성 평가)

  • Kim, Hyun-Gyu;Oh, Se-Young;Kim, Kwang-Soo;Lee, Haeng-Soo;Kim, Seong-Woong;Kim, Jae-Hyun
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.37 no.2
    • /
    • pp.233-239
    • /
    • 2013
  • In this paper, a method of combining numerical analyses and experimental tests is used to evaluate fracture toughness of copper thin films of $15{\mu}m$ thickness. Far-field loadings of a global-local finite element model are inversely estimated by matching crack opening profiles in experiments with numerical results. The fracture toughness is then evaluated using the J-integral for cracks in thin films under far-field loadings. In experiments, Cu thin films attached to Aluminum sheets are loaded indirectly, and crack opening profiles are observed by microscope camera. Stress versus strain curves of Cu thin films are obtained through micro-tensile tests, and the grain size of Cu thin films is observed by TEM analysis. The results show that the fracture toughness of Cu thin films with $500nm{\sim}1{\mu}m$ sized grains is $6,962J/m^2$.

Synthesis and Characterization of Poly(L-lactide)(L-PLA), Poly(D-lactide)(D-PLA) and Stereocomplex-poly(lactide)(PLA) (L-폴리락타이드, D-폴리락타이드의 활성과 입체복합체 폴리락타이드의 제조 및 특성연구)

  • Kim, Ji-Hyun;JeGal, Jong-Geon;Song, Bong-Keun;Shin, Chae-Ho
    • Polymer(Korea)
    • /
    • v.35 no.1
    • /
    • pp.52-59
    • /
    • 2011
  • L-PLA or D-PLA was synthesized in bulk at $140^{\circ}C$ by ring opening polymerization(ROP) of L-lactide or D-lactide as a monomer using tin(II) octoate and lauryl alcohol as a catalyst and an initiator with changing the amounts of catalyst(0.25~1.0 wt%) and initiator(0.l~0.5 wt%). And stereocomplex-PLA was prepared by L-PLA/D-PLA having a wide range of molecular weight(30000~90000 g/mol) and L-PLA/D-PLA blends having different mixing ratio ($X_D$). The melting temperature. thermal degradation temperature and thermal stability of stereocomplex-PLA were higher than those of homopolymers(L-PLA, D-PLA). We supposed that these improvements arose from a strong interaction between L-PLA and D-PLA. The improved mechanical properties and changes in morphology of LPLA/D-PLA blends were compared to those of homopolymers(L-PLA, D-PLA).

Flexibility Study of Silicon Thin Film Transferred on Flexible Substrate (폴리머 기판 위에 전사된 실리콘 박막의 기계적 유연성 연구)

  • Lee, Mi-Kyoung;Lee, Eun-Kyung;Yang, Min;Chon, Min-Woo;Lee, Hyouk;Lim, Jae Sung;Choa, Sung-Hoon
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.20 no.3
    • /
    • pp.23-29
    • /
    • 2013
  • Development of flexible electronic devices has primarily focused on printing technology using organic materials. However, organic-based flexible electronics have several disadvantages, including low electrical performance and long-term reliability. Therefore, we fabricated nano- and micro-thick silicon film attached to the polymer substrate using transfer printing technology to investigate the feasibility of silicon-based flexible electronic devices with high performance and high flexibility. Flexibility of the fabricated samples was investigated using bending and stretching tests. The failure bending radius of the 200 nm-thick silicon film attached on a PI substrate was 4.5 mm, and the failure stretching strain was 1.8%. The failure bending radius of the micro-thick silicon film attached on a FPCB was 2 mm, and the failure strain was 3.5%, which showed superior flexibility compared with conventional silicon material. Improved flexibility was attributed to a buffering effect of the adhesive between the silicon film and the substrate. The superior flexibility of the thin silicon film demonstrates the possibility for flexible electronic devices with high performance.

Analysis of Mechanical Properties and Stress Crack Behavior of HOPE Geomembranes by Laboratory Installation Damage Test (실내 시공시 손상시험에 의한 HDPE 지오멤브레인의 기계적 특성 및 응력균열거동 해석)

  • Khan, Belas Ahmed;Park, Ju-Hee;Kim, Sung-Hee;Chang, Yong-Chai;Oh, Tae-Hwan;Lyoo, Won-Seok;Jeon, Han-Yong
    • Polymer(Korea)
    • /
    • v.35 no.3
    • /
    • pp.203-209
    • /
    • 2011
  • Two smooth and textured surfaced HDPE geomembranes (GMs) were cut into dumbbell shape and notched where depth of the notch produced a ligament thickness of 10% to 90% of the nominal thickness with the specimen at 10% interval. A series of laboratory simulation test for installation damage were carried out at different loading cycles on HDPE GMs in accordance with ISO 10722 test method and the effect of number of loading cycle on installation damage was compared. It was found that yield stress and elongation at yield point decreased gradually as the notch depth was increased. Both installation damaged and notched, GMs were used to understand stress crack behavior and this behavior was observed through NCTL test at $50{\pm}1^{\circ}C$ at different yield stresses immerging in pH 4 and pH 12 buffer solutions. Over 35% tensile load, GMs became vulnerable to stress cracking. Both damaged and notched GMs showed the same trend. Especially, notched GMs showed less strength than installation damaged GMs at every stress cracking test condition.

The Production, Distribution, and Utilization of Rice in Japan (일본의 쌀 생산, 유통 및 이용 현용)

  • Inouchi, Naoyoshi
    • Food preservation and processing industry
    • /
    • v.1 no.1
    • /
    • pp.17-26
    • /
    • 2002
  • 일본은 기후적으로도 쌀의 생산에 적합하며 쌀은 일본의 주곡이다. 1893년 국립농업연구소가 설치된 이래로 쌀은 품질과 단보당 생산량이 꾸준히 개선되어와 116의 노동시간으로 생산량은 2.5배의 증가를 가져왔다. 이러한 진전은 재배방법의 개선, 비료, 농약, 재배기술, 기계화, 관개배수, 농지개량 등의 요인들로 볼 수 있다. 현재 일본에서 생산되고 있는 주요 쌀 품종으로는 코시히카리($35.5\%$), 히토메보레($9.7\%$), 히노히카리($9.0\%$), 아키다코마치($8.5\%$), 키라라($4.8\%$) 등 10여 품종이며 최근에는 형질전환 품종의 연구와 함께 생물공학적 연구 ,생리, 품질, 곤충과 잡초, 토양, 식품가공 등 기본적인 연구에 심혈을 기울이고 있다. 새로운 형태의 쌀 품종으로는 냉동조리쌀밥, 초밥, 레토르트룡 쌀 등 가공용으로 적합하도록 하기 위하여 아밀로오즈의 함량을 $5-15\%$로 낮춘 쌀이나 카레, 필라프, 튀김 쌀 등의 용도에 적합하도록 아밀로오스의 함량을 $30\%$이상으로 높인 쌀뿐만 아니라 곡립의 크기와 길이 등을 변형시킨 쌀, 유색미, 향미, 단백질 함량 조절 쌀, 거대 배아미, lipoxygenase 활성을 없앤 쌀, 단맛나는 쌀 등이 연구, 생산되고 있다. 일본에서의 쌀이용은 먼저 가공용 쌀을 들 수 있다. 밥, 청주, 스낵, 쌀가루, 미소발효 등 다양하게 이용이 되고 있으며 parboiled rice와 이의 색과 향을 개선한 converted rice, 현미를 이용한 가공쌀, 쌀빵, 현미가루, 세척미, 쌀국수, 쌀스낵, 당과, 죽, 쌀은 채소아 함께하는 타키코미고한, 초밥, 냉동쌀밥, 무균포장밥, 건조밥, 즉석밥 등 매우 다양하다.는 일, 쌀 재배구조 조정과 함께 높은 미질을 가지는 품종육종, 기계화를 비롯한 경작기술의 발달, 쌀과 부산물 가공기술의 개발연구, 특정기능을 함유하는 유전공학적 기술의 적용, 토지와 도시화 그리고 식량순환에 시스템의 개혁 등 과학기술을 고양하는 일 등을 들 수 있다.하는데 도움이 되리라 생각된다.=0.002)가 통계적으로 유의한 인자였다. 결론 : 본 기관에서 시행되어진 근침윤성 방광암에 대한 방광보존치료법은 기존의 근치적 방광절제술에 비하여 대등한 치료성적을 내는 동시에 $63\%$에서 장기보존이 가능하였다. 따라서 본 치료법이 방광암의 치료에 적극적으로 적용되어야 할 것으로 생각하며 향후 여러 기관이 참여하는 활발한 연구를 통해 한국인에게 가장 적절한 치료법을 개발해야 될 것으로 생각한다. B2+3, C1, C2+3군에서 수술달독군과 방사선치료 추가군의 골반종양제어율은 각각 $79\%$$75\%$ (p=0.88), $100\%$$100\%,\;44\%$$68\%$ (p=0.01)이었다. 전체 환자를 대상으로 다요인 분석을 시행한 결과 생존율과 무병생존율에 병기만이 유의하였고 두 치료 군에서도 역시 병기가 유의한 인자로 나타났다. 전체환자에서 골반종양제어율에 유의한 예후인자로 다요인분석을 시행한 결과 병기와 수술방법이 유의하였다. 수술단독군에서는 병기만이 유의하였고 방사선치료 추가군에서는 수술방법만이 유의하여 복부회음절제술군의 골반종양재발률이 높았다. 결론 : 본 후향적 연구에서 수술 후 보조적 방사선치료를 시행하여 수술단독군에 비해 병기 C2+3군에서 골반종양제어율이 향상되었음을 알 수 있었다. 그러나 병기 B2이상의 모든 환자에서 골반종양제어율 뿐만 아니라 생존율의 향상을 가져오기

  • PDF

Development of Leg Stiffness Controllable Artificial Tendon Actuator (LeSATA®) Part I - Gait Analysis of the Metatarsophalangeal Joint Tilt Angles Soonhyuck - (하지강성 가변 인공건 액추에이터(LeSATA®)의 개발 Part I - Metatarsophalangeal Joint Tilt Angle의 보행분석 -)

  • Han, Gi-Bong;Eo, Eun-Kyung;Oh, Seung-Hyun;Lee, Soon-Hyuck;Kim, Cheol-Woong
    • Transactions of the KSME C: Technology and Education
    • /
    • v.1 no.2
    • /
    • pp.153-165
    • /
    • 2013
  • The established gait analysis studies have regarded leg as one single spring. If we can design a knee-ankle actuating mechanism as a primary actuator for supporting knee extension, it might be possible to revolutionary store or release elastic strain energy, which is consumed during the gait cycle, and as a result leg stiffness is expected to increase. An ankle joint actuating mechanism that stores and releases the energy in ankle joint is expected to support and solve excessive artificial leg stiffness caused by the knee actuator (primary actuator) to a reasonable extent. If unnecessary kinematic energy is released with the artificial speed reduction control designed to prevent increase in gait speed caused by increase in time passed, it naturally brings question to the effectiveness of the actuator. As opposed to the already established studies, the authors are currently developing knee-ankle two actuator system under the concept of increasing lower limb stiffness by controlling the speed of gait in relative angular velocity of the two segments. Therefore, the author is convinced that compensatory mechanism caused by knee actuating must exist only in ankle joint. Ankle joint compensatory mechanism can be solved by reverse-examining the change in metatarso-phalangeal joint (MTPJ) tilt angle (${\theta}_1=0^{\circ}$, ${\theta}_2=17^{\circ}$, ${\theta}_3=30^{\circ}$) and the effect of change in gait speed on knee activity.