• Title/Summary/Keyword: Compression displacement

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A study on the electrical properties of lipid monolayers by displacement current method (변위전류법에 의한 지질단분자막의 전기특성에 관한 연구)

  • 이경섭;권영수
    • Electrical & Electronic Materials
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    • v.9 no.5
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    • pp.450-454
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    • 1996
  • Maxwell-Displacement-Current(MDC) measuring technique has been applied to the study of monolayers of Dilauroylphosphatidylcholine (L-.alpha.-DLPC) and Dimyristoylphosphatidylcholine (L-.alpha.-DMPC). The displacement current was generated from monolayers on a water surface by monolayer compression. Displacement current was generated when the area per molecule was about 250.angs.$^{2}$, 280.angs.$^{2}$. Displacement current was generated in the gas state, gas/liquid state, and liquid state in the course of monolayer compression. The orientational change of molecules in monolayers was discussed on the basis of the MDCs obtained. Finally, we measured differential thermal analysis of sample.

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A Study on the Photoisomerization of Fatty Acid and Polyamic Acid Mixture (지방산과 폴리아미드산 혼합물의 광이성질화 현상에 관한 연구)

  • 박근호;박태곤
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.8
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    • pp.695-701
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    • 2002
  • Maxwell displacement current (MDC) measuring technique has been applied on the study of monolayers of fatty acid and polyamic acid mixture. The displacement current was generated from monolayers on the water surface by monolayer compression and expansion. Displacement current was generated when the area per molecule was about 132 $^2$and 115 $^2$just before the initial rise of the surface pressure during the 1st and 2nd mixed monolayer compressions cycle, respectively. Maxwell displacement currents were investigated in connection with mixed monolayer compression cycles. It was found that the maximum of MDC appeared at the molecular area just before the initial rise of surface pressure in compression cycles. Ultra thin film of fatty acid and polyamic acid mixture was prepared on the hydrophilic quartz plate by Langmuir-Blodgett (LB) method. The precursor LB film was heated in a vacuum dry oven at 12$0^{\circ}C$ in order to convert it into the LB film of polyimide. The absorption spectra of LB films were also induced photoisomerization by UV and visible light irradiation.

The Study on Pullout Resistance Characteristics of the Compression Anchor by Pullout Tests on the Field (현장실험에 의한 압축형 앵커의 인발거동특성 연구)

  • 홍석우
    • Journal of Ocean Engineering and Technology
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    • v.16 no.2
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    • pp.44-52
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    • 2002
  • The mechanism of pullout resistance of compression anchor is analysed. This anchor is developed through the field pullout tests and the laboratory element test. The compression anchor is characterized by decrease of progressive failure, simple site work, economy and durability compared with tension anchor. The characteristics of compression anchor, compared with tension anchor. mainly are summarized as follows ; (1) The plastic displacement of anchor body is very small during pullout of anchor. (2) Total anchor length decreases by the shortening of free length; (3) The progressive failure is decreased.; (4) The safety factor for pullout resistance increases with time after construction of anchor.

Theoretical analysis of tensile stresses and displacement in orthotropic circular column under diametrical compression

  • Tsutsumi, Takashi;Iwashita, Hiroshi;Miyahara, Kagenobu
    • Structural Engineering and Mechanics
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    • v.38 no.3
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    • pp.333-347
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    • 2011
  • This paper shows the solution for an orthotropic disk under the plane strain condition obtained with complex stress functions. These stress functions were induced by Lekhnitskii and expanded by one of the authors. Regarding diametrical compression test, the finite element method poses difficulties in representing the concentrated force because the specimens must be divided into finite elements during calculation. On the other hand, the method shown in this study can exactly represent this force. Some numerical results are shown and compared with those obtained under the plane stress condition for both stress and displacement. This comparison shows that the differences between the tensile stresses occurred under the plane strain condition and also that the differences under a plane stress condition increase as the orthotropy ratio increases for some cases.

Theoretical study of sleeved compression members considering the core protrusion

  • Zhang, Chenhui;Deng, Changgen
    • Structural Engineering and Mechanics
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    • v.66 no.6
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    • pp.783-792
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    • 2018
  • This paper presents a detailed theoretical study of the sleeved compression members based on a mechanical model. In the mechanical model, the core protrusion above sleeve and the contact force between the core and sleeve are specially taken into account. Via the theoretical analyses, load-displacement relationships of the sleeved compression members are obtained and verified by the experimental results. On the basis of the core moment distribution changing with the increase of the applied axial load, failure mechanism of the sleeved compression members is assumed and proved to be consistent with the experimental results in terms of the failure modes and the ultimate bearing capacities. A parametric study is conducted to quantify how essential factors including the core protrusion length above sleeve, stiffness ratio of the core to sleeve, core slenderness ratio and gap between the core and sleeve affect the mechanical behaviors of the sleeved compression members, and it is concluded that the constrained effect of the sleeve is overestimated neglecting the core protrusion; the improvement of ultimate bearing capacity for the sleeved compression member is considered to be decreasing with the decrease of the core slenderness ratio and for the sleeved compression member with core of small slenderness ratio, small gap and small stiffness ratio are preferred to obtain larger ultimate bearing capacity and stiffness.

Estimation of rock tensile and compressive moduli with Brazilian disc test

  • Wei, Jiong;Niu, Leilei;Song, Jae-Joon;Xie, Linmao
    • Geomechanics and Engineering
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    • v.19 no.4
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    • pp.353-360
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    • 2019
  • The elastic modulus is an important parameter to characterize the property of rock. It is common knowledge that the strengths of rocks are significantly different under tension and compression. However, little attention has been paid to the bi-modularity of rock. To validate whether the rock elastic moduli in tension and compression are the same, Brazilian disc, direct tension and compression tests were conducted. A horizontal laser displacement meter and a pair of vertical and transverse strain gauges were applied. Four types of materials were tested, including three types of rock materials and one type of steel material. A comprehensive comparison of the elastic moduli based on different experimental results was presented, and a tension-compression anisotropy model was proposed to explain the experimental results. The results from this study indicate that the rock elastic modulus is different under tension and compression. The ratio of the rock elastic moduli under compression and tension ranges from 2 to 4. The rock tensile moduli from the strain data and displacement data are approximate. The elastic moduli from the Brazilian disc test are consistent with those from the uniaxial tension and compression tests. The Brazilian disc test is a convenient method for estimating the tensile and compressive moduli of rock materials.

Research on hysteretic characteristics of EBIMFCW under different axial compression ratios

  • Li, Sheng-cai;Lin, Qiang
    • Earthquakes and Structures
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    • v.22 no.5
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    • pp.461-473
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    • 2022
  • Energy-saving block and invisible multiribbed frame composite wall (EBIMFCW) is an important shear wall, which is composed of energy-saving blocks, steel bars and concrete. This paper conducted seismic performance tests on six 1/2-scale EBIMFCW specimens, analyzed their failure process under horizontal reciprocating load, and studied the effect of axial compression ratio on the wall's hysteresis curve and skeleton curve, ductility, energy dissipation capacity, stiffness degradation, bearing capacity degradation. A formula for calculating the peak bearing capacity of such walls was proposed. Results showed that the EBIMFCW had experienced a long time deformation from cracking to failure and exhibited signs of failure. The three seismic fortification lines of the energy-saving block, internal multiribbed frame, and outer multiribbed frame sequentially played important roles. With the increase in axial compression ratio, the peak bearing capacity and ductility of the wall increased, whereas the initial stiffness decreased. The change in axial compression ratio had a small effect on the energy dissipation capacity of the wall. In the early stage of loading, the influence of axial compression ratio on wall stiffness and strength degradation was unremarkable. In the later stage of loading, the stiffness and strength degradation of walls with high axial compression ratio were low. The displacement ductility coefficients of the wall under vertical pressure were more than 3.0 indicating that this wall type has good deformation ability. The limit values of elastic displacement angle under weak earthquake and elastic-plastic displacement angle under strong earthquake of the EBIMFCW were1/800 and 1/80, respectively.

A Study on the Stimulus Reaction of PBLG (Poly-${\gamma}$-Benzyl $_L$-Glutamate의 자격반응에 관한 연구)

  • Kim, Beyung-Geun;Lee, Kyung-Sup
    • Proceedings of the KIEE Conference
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    • 2002.07c
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    • pp.1413-1415
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    • 2002
  • The Displacement current measurement system used in this experiment because detecting the dynamic behavior of monolayers at the air-water interface is possible. It basically consists of a film balance, a pair of electrodes connected to each other through a sensitive ammeter. Here, one electrode is suspended in air and the other electrode is placed in the water. PBLG phase transformation measured by Maxwell-displacement-current-measurement method in surface of the water. Measured (surfacc pressure, displacement current and dipole moment) of monolayers of PBLG on the water surface. We measured displacement current that occur when changed temperature(15, 20, 25$^{\circ}$ ) and the compression speed(30, 40, 50(mm/min)). From the result, it is known that curren generated in the range of high surface pressur compression velocity and temperature become faste.

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The Measurement of Maxwell Displacement Current of Phospholipid Monolayers on the Water Surface

  • Park, Keun-Ho
    • Journal of the Korean Applied Science and Technology
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    • v.14 no.2
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    • pp.35-40
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    • 1997
  • The organization of phospholipid monolayers and their monolayers mixed with fatty acid containing azobenzene on the water surface was investigated by means of the displacement current measurement method. The phase transition from the gaseous phase to the gaseous-fluid phase which accompanies the polar ordering of phospholipid molecules was detected in the range of immeasurably low surface pressure. The molecular area which gives the onset of the transition was determined for phospholipid monolayers. The Maxwell displacement current(MDC) pulses were generated across mixed monolayers due to the photoisomerization of fatty acid containing azobenzene by alternating irradiation of ultraviolet and visible light, because the condensation of pure azobenzene monolayers was loosened by the introduction of phospholipids into the monolayers. The displacement currents generated during light irradiation were also investgated in connection with monolayer compression cycles. It was found that the maximum of MDC appeared at the molecular area just before the initial rise of surface pressure in compression cycles.

"In the Beginning was the Deed": Sigmund Freud's Auditory Imagination

  • KIM, TaeChul
    • English & American cultural studies
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    • v.9 no.1
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    • pp.113-139
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    • 2009
  • Such is an elective affinity between literary studies and psychoanalysis that the latter sometime serves as a form of literary pedagogy. The affinity mainly consists in their shared concern for language. The signification of language in psychoanalysis is much similar to that of literature. Many of psychoanalytic terms and theoretical tenets bear witness to its dependence clinically on speech phenomena and theoretically on language in general. It is most true of Sigmund Freud, for whom the unconscious is in effect the linguistic unconscious. The Freudian unconscious, compressing and displacing through images and ideas, works as a text for psychoanalysis, which approach has not only paved one of the ways to poststructuralist anti-essentialism but with which literary studies also feel uncanny familiarity. Freudian psychoanalysis, starting empirically from clinical observations, discovers that words exist independent of meanings in the form of things in the unconscious system. Out of the various sensory elements of a word-thing, in psychoanalytic terms, the auditory is central. Now with the auditory imagination cultivated in the clinic, Freud figures out compression and displacement as the chief unconscious works, of which my main argument is that they are based phonetically on heteronym and homonym associations respectively. Compression and displacement work to be masks, which excites Freud's sense of challenge: his is a kind of poststructuralist approach, in the sense that the closed interrelatedness of words without external referents determines the signification in a given situation. But the works of compression and displacement, viewed in auditory terms rather than mapped on to metaphor and metonymy, can provide a new insight for a literary reading of Freud. Pursuing Freud's auditory imagination is not only an attempt to read his writing as literary text rather than for theoretical discussion, but also an experiment with the possibility of literary reading of a theoretical text in the age of after-theory.