• Title, Summary, Keyword: PES

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Toughening of Epoxy Resin with PES-CTBN-PES Triblock Copolymers (PES-CTBN-PES 공중합체를 이용한 에폭시 수지의 강인성 향상 연구)

  • 김형륜;명범영;송경헌;육종일;윤태호
    • Polymer Korea
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    • v.25 no.2
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    • pp.246-253
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    • 2001
  • Amino terminated PES-CTBN-PES triblock copolymer was synthesized from PES oligomer and commercial CTBN rubber (CTBN1300$\times$13), and molecular weight of the copolymer was controlled to be 15000 g/mole. The copolymer was utilized to toughen diglycidyl ether of bisphenol-A (DGEBA) epoxy resin which was cured with 4,4'-diaminodi-phenylsulfone (DDS) and subjected to the measurement of thermal properties, fracture toughness ( $K_{IC}$), flexural properties and solvent resistance. The properties were compared with those from the samples modified by CTBN/PES blends. The maximum loading of copolymer into the epoxy resin was 40 wt% without utilizing solvent, at which $K_{IC}$ fracture toughness of 2.21 MPa${\cdot}m^{0.5}$ was obtained without sacrificing flexural properties and chemical resistance. However, the epoxy resin modified with PES/CTBN blend exhibited much lower $K_{IC}$ and flexural properties compared to the epoxy resins toughened by PES-CTBN-PES copolymers.

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The Differences in Foot Type According to Major in Left and Right Foot for Female College Students (전공과 좌우 양 발에 따른 여대생의 발 유형 분석)

  • Yi, Kyung-Ock;Kim, Nam-Hee;Kim, You-Ryun
    • Korean Journal of Sport Biomechanics
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    • v.22 no.2
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    • pp.229-236
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    • 2012
  • The purpose of this study is to analyze the differences in foot type of female college students according to academic major in both feet. The subjects for this study were 216 female students who took liberal arts classes in Seoul. Dependent variables were students' field of study -specifically whether or not they majored in physical education. Analysis of students' foot type and Malalignment Syndrome were measured using Resting Calcaneous Stance Position (RCSP). There were five categories for RCSP angle: Severe Pes Planus (< $-5^{\circ}$), Pes Planus ($-3^{\circ}{\sim}-4^{\circ}$), Pes Rectus (${\pm}2^{\circ}$), Pes Cavus ($+3^{\circ}{\sim}+4^{\circ}$), Severe Pes Cavus (> $+5^{\circ}$). ${\chi}^2$ analysis was used for statistical analysis. RCSP for all subjects (432 feet) occurred at the following frequency: Pes Planus(43.9%), Pes Rectus(43.8%), and Pes Cavus(12.3%). These levels were different for physical education majors, with Pes Planus at 42.6%, Pes Rectus at 49.4%, and Pes Cavusat 8.0%. Non-physical education majors exhibited Pes Planus at 45.0%, Pes Rectus at 39.9%, and Pes Cavus at 15.1%. 15.3% (33 subjects) of all students had Malalignment Syndrome. In conclusion, 56.2% of female college students had a foot deformity. There was nearly four times more Pes Planus than Pes Cavus. According to these results, exercise can be prescribed to alleviate foot deformities, especially supination. Severe pronation and supination problems appeared less amongst students not majoring in physical education. Thus, although exercise might be one cause of foot deformity, it can also help resolve problems with over-supination. Further study will be needed to understand and resolve the specific mechanism of over-supination.

A Research on Personal Environment Services for a Smart Home Network (스마트 홈 네트워크를 위한 개인환경서비스 연구)

  • Ro, Kwang-Hyun;Kim, Seung-Cheon
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.49 no.3
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    • pp.46-55
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    • 2012
  • Recently, the concept of PES(Personal Environment Service) is being widely discussed on various standardization organizations such as ITU-R, ETSI, 3GPP, TTA and etc. The purpose of PES is to introduce the services which can dynamically, automatically and intelligently reconfigures the electronic, electrical, and mechanical equipment surrounding the user according to the user preferences included in a user's profile by using a smartphone embedding WPAN radio technologies such as bluetooth and WiFi. This research introduces an Android Platform-based PES system which consists of a PES app, PES devices and a PES server. A smartphone platform is Android 2.2(Froyo) version and 4 simulated PES devices were implemented by using Galaxy Tab. It has shown that the PES would be a killer application of M2M(Machine-to-Machine) or D2D(Device-to-Device) in the future and it would need to study how to update a user's profile based on analyzing user's behaviour for enhancing the PES user's satisfaction.

Splicing Techniques in the PES System Layer for the Editing at a GOP Module of The MPEG-2 based Images (MPEG-2 기반영상 GOP 단위 편집을 위한 PES 시스템 영역에서의 스트림 접함 방법)

  • 김동준;최윤식
    • Journal of Broadcast Engineering
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    • v.7 no.4
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    • pp.355-361
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    • 2002
  • In this paper, several methods which guarantee the seamless editing when the splicing is applied to the MPEG-2 system streams are described. In the MPEG-2 system standard, it is recommended that the splicing technique is applied in the Transport Stream(TS) domain. However, in view of the video editing, the splicing at an arbitrary picture unit can not be guaranteed. The splicing in the PES domain is only considered in this paper because the PES is one of the MPEG-2 system streams and this result could be directly extended to the video splicing techniques in the TS or PS domain. Thus. the problems that might occur when different two PES streams are spliced and its effects to the video quality are compared and analyzed. Based on this analysis. several methods that can resolve these problems directly in the PES domain are proposed. Consequently, the computer simulation demonstrates that the splicing at a GOP modulo is guaranteed to have good video quality even without considering the state of the PES packet only if the PES_packet_length field of the PES packet header is used.

A Study on Time Synchronization for Programmable Electronic Systems of Train Control (열차제어 장치용 실시간 시스템의 시간 동기화에 관한 연구)

  • Kang, Shin Ju;Lee, Jong Woo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.7
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    • pp.1019-1023
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    • 2014
  • The issue of safety insurance in PES(Programmable Electronic Systems) has been provoked because PES is difficult to define failure modes which are appeared in many different ways. But the PES applications extend rapidly in various areas. One of the solutions for PES safety insurance is voting which PES is used by comparing the outputs of several PES. The time synchronization of the PES is necessary for this reliable voting. The voting must be carried out with the outputs from same time inputs. There are several methods for time synchronization of the PES. In this paper, we discussed two modes of the time synchronization which are mutual synchronization of several PES and using UTC(Universal Time Clock).

Study on Characteristics of Various RF Transmission Line Structures on PES Substrate for Application to Flexible MMIC

  • Yun, Young;Kim, Hong Seung;Jang, Nakwon
    • ETRI Journal
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    • v.36 no.1
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    • pp.106-115
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    • 2014
  • In this work, the coplanar waveguide is fabricated on a PES (poly[ether sulfone]) substrate for application to a flexible monolithic microwave integrated circuit, and its RF characteristics were thoroughly investigated. The quality factor of the coplanar waveguide on PES is 40.3 at a resonance frequency of 46.7 GHz. A fishbone-type transmission line (FTTL) structure is also fabricated on the PES substrate, and its RF characteristics are investigated. The wavelength of the FTTL on PES is 5.11 mm at 20 GHz, which is 55% of the conventional coplanar waveguide on PES. Using the FTTL, an impedance transformer is fabricated on PES. The size of the impedance transformer is $0.318mm{\times}0.318mm$, which is 69.2% of the size of the transformer fabricated by the conventional coplanar waveguide on PES. The impedance transformer showed return loss values better than -12.9 dB from 5 GHz to 50 GHz and an insertion loss better than -1.13 dB in the same frequency range.

Sonoanatomic Variation of Pes Anserine Bursa

  • Imani, Farnad;Rahimzadeh, Poupak;Gharehdag, Farid Abolhasan;Faiz, Seyed Hamid Reza
    • The Korean Journal of Pain
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    • v.26 no.3
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    • pp.249-254
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    • 2013
  • Background: The pes anserine bursa lies beneath the pes anserine tendon, which is the insertional tendon of the sartorius, gracilis, and semitendinosus muscles on the medial side of the tibia, but it can lie in different sites in the medial knee. Accurate diagnosis of the position of the bursa is critical for diagnostic and therapeutic goals. The aim of this study was to evaluate sonoanatomic variations of the pes anserine bursa in the medial knee. Methods: One hundred seventy asymptomatic volunteers were enrolled in this study. Using ultrasound imaging (transverse approach, 7-13 MHz linear array probe) the sonoanatomic position of the pes anserine bursa and its relation to the pes anserine tendon were evaluated. Additionally, we evaluated the sonoanatomic variation of the saphenous nerve. Results: The position of the pes anserine bursa was between the medial collateral ligament and the pes anserine tendons in 21.2%/18.8% (males/females) of subjects; between the pes anserine tendons and the tibia in 67.1%/64.7% (m/f); and among the pes anserine tendons in 8.2%/12.9% (m/f). No significant differences in the position of the bursa existed between males and females. The saphenous nerve was found within the pes anserine tendons in 77.6%/74.1% (m/f) of subjects, but outside the pes anserine tendons in 18.8%/15.3% (m/f). Visibility of sonoanatomic structures was not related to either gender or BMI. Conclusions: Ultrasound provides very accurate information about variations in the pes anserine bursa and the saphenous nerve. This suggests that our proposed ultrasound method can be a reliable guide to facilitate approaches to the medial knee for diagnostic and therapeutic objectives.

Enhanced Hydrophilicity of Polyethersulfone Membrane by Various Surface Modification Methods (다양한 표면개질을 이용한 폴리에테르설폰 막의 친수성 향상)

  • Park, So Jung;Hwang, Jun Seok;Choi, Won-Kil;Lee, Hyung Keun;Huh, Kang Moo
    • Polymer Korea
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    • v.38 no.2
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    • pp.205-212
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    • 2014
  • Polyethersulfone (PES) membranes were modified by various physico-chemical modification methods to enhance the surface hydrophilicity for application as a separation membrane to separate and collect water vapor from the flue gas. Homogeneous PES flat-sheet membranes were prepared and modified by acid treatment, blending and plasma treatment for hydrophilic surface modification. The surface characteristics of the modified PES membranes were evaluated by ATR-FTIR, XPS, SEM and contact angle measurements. No significant change in hydrophilicity was observed for the PES membranes modified by acid treatment with sulfuric acid or blending with various compositions of poloxamer as an amphiphilic PEO-PPO-PEO tri-block copolymer. On the other hand, Ar plasma treatment led to a significant increase in the hydrophilicity of the surface, depending on the plasma treatment time. As a result, the PES membrane could be the most efficiently surface-treated by applying the plasma treatment for enhancing their surface hydrophilicity.

Enhancing Fracture Toughness of Epoxy Resins with CTBN-PES Block Copolymer (CTBN-PES Block Copolymer에 의한 에폭시 수지의 강인화 연구)

  • 김형륜;육종일;윤태호
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.172-176
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    • 1999
  • 에폭시 수지의 강인성 향상을 위하여 양말단에 아민 반응기를 가지는 PES-CTBN-PES triblock copolymer를 합성하여 이를 에폭시 수지의 강인화제로 사용하였으며 경화제로는 p-DDS(p-dichlorodiphenylsulfone)를 사용하였다. 또한 공중합체에 의한 물성 향상효과를 CTBN과 PES-NH$_2$의 블렌드에 의한 경우와 비교하였다. 강인화된 에폭시 수지의 물성은 강인성 및 굴곡특성을 측정하여 분석하였으며, 열특성은 DSC, TGA, 및 DMA에 의해 실시되었다. 그리고 강인화된 에폭시 수지의 강인성 향상 mechanism을 규명하기 위하여 파단면을 SEM으로 분석하여 상분리 거동을 고찰하였다. 높은 유리전이온도와 우수한 기계적 물성을 가지는 고성능 기능성 폴리설폰(PES-NH$_2$)과 상용 액상 고무 첨가제인 CTBN을 이용하여 합성된 공중합체를 강인화제로 사용함으로써 열안정성, 탄성률 및 내식성의 감소없이 에폭시 수지의 쳐대 단점인 강인성을 최적 수준으로 개선시킬 수 있었으며 공중합체의 에폭시 수지에 대한 우수한 용해도에 따른 가공성이 향상되었다.

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A Study for the PES Service System Architecture (PES 서비스 시스템 구조에 관한 연구)

  • Oh, Jong-Taek
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.5B
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    • pp.471-476
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    • 2011
  • A improved system and protocol architecture for Personal Environment Service which has been created recently, is proposed in this paper. PES is the typical mobile convergence service based on smart phone and user profile, and its influence would be very huge in the near future. In order to make it feasible more efficiently, the system architecture should be studied from the early stage. The proposed PES system and protocol architecture could be valuable reference for the further study and development of PES system and technology.