• Title/Summary/Keyword: Relaxation Time

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A Study on the User′s Pattern and Characteristics of Jeol-young Seaside Park (절영해안산책공원 이용객의 이용패턴과 특성에 관한 연구)

  • Lee, Myung-Kwan
    • Journal of Navigation and Port Research
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    • v.28 no.5
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    • pp.455-462
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    • 2004
  • Recently, according to the increase of personal income and enough time to spare. people demand the expansion of waterfront space in the city and the development of waterfront's possibility. In this study, which takes a place of the Jeol-young seaside park in young-do investigated for the user's pattern of seaside park located in coastal area And analyzed into user's attributes and a feeling of satisfaction The results of this study were as follows : 1) The Jeol-young seaside park is facilitated for taking a walk. It also tends to be preferred for the ocean view, jogging, relaxation, and so on 2) The Jeol-young seaside park has to be ensured with its safety and convenience of esplanade. In order to provide the user's high satisfaction, more facilities of expansion and parking area are demanded to be developed.

Managing method for stud female threads used long period under high temperature on the power plants (장기간 사용된 발전설비용 고온 스터드 암나사부 관리방법)

  • Chung, Nam-Yong;Kim, Moon-Young
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.199-205
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    • 2000
  • The stud female threads for stud bolts tend to degrade faster by high temperature over 450 C. Therefore, inspection for replacement cycle of stud bolts is used to carry out many kinds of method such as ultrasonic test(UT), magnetic test(MT), wobble test, visual test and hardness test. The visual inspection among those has been only applied for stud female threads generally and wobble test is often used to apply stud bolts. In this paper, wobble test is applied for evaluation of stud female threads on the contrary stud bolts especially. It is also applied three types of inspection method included wobble test on the two sites which is used for each other different operation cycle and three kinds of acquisition data are compared with evaluation methods. From the results, we have studied the characteristic exchanging of integrity evaluation data distribution according to using time and proposed managing method for female thread of stud on the power plants.

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Changes in Physical Properties of Paper by Solvent-Bonding between Cellulose Fibers Using Aqueous Solution of N-Methylmorpholine N-Oxide (N-Methylmorpholine N-Oxide 수용액을 이용한 셀룰로오스 섬유들간의 용제접착에 의한 종이의 물성 변화)

  • 이양헌;박찬헌;이현진;이선희
    • Textile Coloration and Finishing
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    • v.11 no.1
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    • pp.34-41
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    • 1999
  • To examine the increase of paper strength by solvent-bonding using N-methylmorpholine N-oxide (NMMO), a paper was treated with aqueous solutions of NMMO, concentrated at $90^\circ{C}$ for selected periods of time, and pressed for 5 seconds followed by washing and drying. The effect of the increasing NMMO concentration on bonding state and some important properties of samples were mainly investigated. With increasing concentration of NMMO, the degree of bonding between fibers was increased, the fiber cross-sectional shape was changed from 'thin ribbonlike' to 'round rodlike' by swelling with solvent, and the longitudinal waves (crimp) were introduced to fibers, hence the shrinkage, weight per unit area, and thickness of paper were increased. Consequently, the tensile strength and elongation, under standard and wet conditions, and the stiffness were increased, and the water absorption was decreased generally with increasing concentration of NMMO. The moisture regain of treated samples was lower than that of the untreated sample, because of the reduction of space between fibers. But the moisture regain was increased a little with increasing concentration of NMMO due to the fiber swelling with NMMO followed by structural relaxation.

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STORAGE OF BROCCOLI BY MAKING THE WATER STRUCTURED -Suppression of metabolism-

  • Oshita, S.;Seo, Y.;Kawagoe, Y.;Rahman, M.A.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 1996.06c
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    • pp.918-925
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    • 1996
  • The effect of structured water by dissolution of xenon was examined from the view point of the suppression of both browning and respiratory metabolism of broccoli. The structured water is formed duet to hydrophobic interaction when xenon gas dissolves into water. NMR measurements were carried out to determine proton spin-spin relaxation time, T2, for water. There was a difference in proton T2 between distilled water and structured water. This can be interpreted as the change of water structure. Fro the broccoli cut in half stored for 16 days at 279K, the section color did not change appreciably for the sample whose water was structured by dissolution of xenon whose initial partial pressure was 0.39MPa. In contrast to this, the browning of section surface was observed for the sample stored under the condition of nitrogen gas at the same partial pressure as xenon and for the sample stored under atmospheric condition . These results led to the conclusion that the suppression of b owning by oxidation was due to structured water but not to applied pressure. Adding to this, the water structured by xenon has resulted in suppression of respiratory metabolism of broccoli.

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Nonlinear rheology of polymer melts: a new perspective on finite chain extensibility effects

  • Wagner Manfred H.
    • Korea-Australia Rheology Journal
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    • v.18 no.4
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    • pp.199-207
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    • 2006
  • Measurements by Luap et al. (2005) of elongational viscosity and birefringence of two nearly monodisperse polystyrene melts with molar masses $M_{w}$ of $206,000g{\cdot}mol^{-1}$ (PS206k) and $465,000g{\cdot}mol^{-1}$ (PS465k) respectively are reconsidered. At higher elongational stresses, the samples showed clearly deviations from the stress optical rule (SOR). The elongational viscosity data of both melts can be modeled quantitatively by the MSF model of Wagner et al. (2005), which is based on the assumption of a strain-dependent tube diameter and the interchain pressure term of Marrucci and Ianniruberto (2004). The only nonlinear parameter of the model, the tube diameter relaxation time, scales with $M_{w}^{2}$. In order to get agreement with the birefringence data, finite chain extensibility effects are taken into account by use of the $Pad\'{e}$ approximation of the inverse Langevin function, and the interchain pressure term is modified accordingly. Due to a selfregulating limitation of chain stretch by the FENE interchain pressure term, the transient elongational viscosity shows a small dependence on finite extensibility only, while the predicted steady-state elongational viscosity is not affected by non-Gaussian effects in agreement with experimental evidence. However, deviations from the SOR are described quantitatively by the MSF model by taking into account finite chain extensibility, and within the experimental window investigated, deviations from the SOR are predicted to be strain rate, temperature, and molar mass independent for the two nearly monodisperse polystyrene melts in good agreement with experimental data.

InP Quantum Dot - Organosilicon Nanocomposites

  • Dung, Mai Xuan;Mohapatra, Priyaranjan;Choi, Jin-Kyu;Kim, Jin-Hyeok;Jeong, So-Hee;Jeong, Hyun-Dam
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.191-191
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    • 2012
  • InP quantum dot (QD) - organosilicon nanocomposites were synthesized and their photoluminescence quenching was mainly investigated because of their applicability to white LEDs (light emitting diodes). The as-synthesized InP QDs which were capped with myristic acid (MA) were incompatible with typical silicone encapsulants. Post ligand exchange the MA with a new ligand, 3-aminopropyldimethylsilane (APDMS), resulted in soluble InP QDs bearing Si-H groups on their surface (InP-APDMS) which allow embedding the QDs into vinyl-functionalized silicones through direct chemical bonding, overcoming the phase separation problem. However, the ligand exchange from MA to APDMS caused a significant decrease in the photoluminescent efficiency which is interpreted by ligand induced surface corrosion relying on theoretical calculations. The InP-APDMS QDs were cross-linked by 1,4-divinyltetramethylsilylethane (DVMSE) molecules via hydrosilylation reaction. As the InP-organosilicon nanocomposite grew, its UV-vis absorbance was increased and at the same time, the PL spectrum was red-shifted and, very interestingly, the PL was quenched gradually. Three PL quenching mechanisms are regarded as strong candidates for the PL quenching of the QD nano-composites, namely the scattering effect, Forster resonance energy transfer (FRET) and cross-linker tension preventing the QD's surface relaxation.

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The Sewability of polyurethane coated fabrics (폴리우레탄 코팅포의 봉제성능)

  • 신혜원;이정순
    • Journal of the Korean Society of Clothing and Textiles
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    • v.25 no.2
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    • pp.350-357
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    • 2001
  • In this study, seam strength, seam elongation and seam efficiency of polyurethane coated fabrics were examined under various sewing conditions using three kinds of fabrics, four kinds of sewing threads and three kinds of stitch lengths. And the sewability of polyurethane coated fabrics were evaluated by FAST system. The results were as follows: 1. Seam strength decreased with the increase of stitch length. The loop strength of sewing thread and the type of base fabric than the type of coated surface had an effect on seam strength. 2. Seam elongation also decreased with the increase of stitch length and was affected by the type of base fabric. The tensile elongation of polyurethans coated fabric had an effect on seam elongation. 3. Sean efficiency also was related to stitch length, the type of base fabric, and seam strength. The suitable seam efficiency was within 50%∼65% in which polyurethane coated fabric and sewing thread broke at the same time. Therefore PS thin and PPC thin sewing threads and 3mm stitch length were suitable to polyurethane coated fabrics. 4. The relaxation shrinkage(RS) of polyurethane coated fabric was smaller than the smallest value of control chart in FAST system. And the extensibility(E) and the shear rigidity(G) were larger than the largest value.

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The Keystone Flap in Greater Trochanter Pressure Sore

  • Byun, Il Hwan;Kwon, Soon Sung;Chung, Seum;Baek, Woo Yeol
    • Archives of Reconstructive Microsurgery
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    • v.25 no.2
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    • pp.72-74
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    • 2016
  • The keystone flap is a fascia-based island flap with two conjoined V-Y flaps. Here, we report a case of successful treatment of a trochanter pressure sore patient with the traditional keystone flap. A 50-year-old male patient visited our department with a $3{\times}5cm$ pressure sore (grade III) to the left of the greater trochanter that was covered with eschar. Debridement was done and the defect size increased to $5{\times}8cm$ in an elliptical shape. Doppler ultrasound was then used to locate the inferior gluteal artery perforator near the wound. The keystone flap was designed to the medial side. The perforator based keystone island flap covered the defect without resistance. The site remained clean, and no dehiscence, infection, hematoma, or seroma developed. In general, greater trochanter pressure sores are covered with a perforator based propeller flap or fascia lata flap. However, these flaps have the risk of pedicle kinking and require a large operation site. For the first time, we successfully applied the keystone flap to treat a greater trochanter pressure sore patient. Our design was also favorable with the relaxation skin tension lines. We conclude that the keystone flap including a perforator is a reliable option to reconstruct trochanteric pressure sores.

Small Base Station Association and Cooperative Receiver Design for HetNets via Distributed SOCP

  • Lu, Li;Wang, Desheng;Zhao, Hongyi;Liu, Yingzhuang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.12
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    • pp.5212-5230
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    • 2016
  • How to determine the right number of small base stations to activate in multi-cell uplinks to match traffic from a fixed quantity of K users is an open question. This paper analyses the uplink cooperative that jointly receives base stations activation to explore this question. This paper is different from existing works only consider transmitting power as optimization objective function. The global objective function is formulated as a summation of two terms: transmitting power for data and coordinated overhead for control. Then, the joint base stations activation and beamforming problem is formulated as a mixed integer second order cone optimization. To solve this problem, we develop two polynomial-time distributed methods. Method one is a two-stage solution which activates no more than K small base stations (SBSs). Method two is a heuristic algorithm by dual decomposition to MI-SOCP that activates more SBSs to obtain multiple-antennae diversity gains. Thanks to the parallel computation for each node, our methods are more computationally efficient. The strengths and weaknesses of these two proposed two algorithms are also compared using numerical results.

Measurements of Adhesion Force of Micro-Sized Toner Particles Deposited on the Developing Roller Surface in a Non-contact type Laser Printer (비접촉 방식 레이저 프린터 현상롤러 위에 부착된 마이크로 토너 입자의 부착힘 측정)

  • Kim Sang-Yoon;Lee Dae-Young;Sheen Sowon;Eun Jong Moon;Hwang Jungho
    • 정보저장시스템학회:학술대회논문집
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    • 2005.10a
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    • pp.75-80
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    • 2005
  • Study for toner adhesion is known as an important role in electrophotography. In this research, a centrifugal detachment method was used to measure the adhesion force of several hundred particles simultaneously and to determine its sensitivity to particle size. For uncharged toner particles, we estimated the van der Waals force based on the centrifugal farce experiments. Then for charged toner particles, the centrifugal force experiments were carried out. The difference between the results for charged toner particles and the results for uncharged toner particles was compared with the image force calculated from a model which assumed that the toner charge was located at the center of the particle. In the calculations, experimental data obtained by E-SPART (Electrical- Single Particle Aerodynamic Relaxation Time) analyzer were used. The adhesion force of micro-sized toner particles deposited on the DR surface was found to be approximately 1${\~}$3 nN.

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