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Electrical Insulation, IEEE Transactions on

Issue 3 • Date Jun 1989

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Displaying Results 1 - 25 of 25
  • Charging, long-term stability, and TSD measurements of SiO2 electrets

    Publication Year: 1989 , Page(s): 439 - 442
    Cited by:  Papers (17)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (272 KB)  

    SiO2 layers with thicknesses of 150 nm, 1 μm, and 2.5 μm were either thermally grown or made by chemical vapor deposition on silicon wafers. Negative and positive charging of the free SiO2 surface was performed by means of liquid-contact, corona, and electron-beam methods. Partially penetrating electrons were used to charge the volume of 2.5-μm-thick SiO2 ... View full abstract»

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  • Measurement applications based on pyroelectric properties of ferroelectric polymers

    Publication Year: 1989 , Page(s): 503 - 516
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (960 KB)  

    Ferroelectric polymers such as polyvinylidene fluoride and vinylidene fluoride-based copolymers can be used in place of single crystals and ceramics in many devices. In addition, their availability as large-surface-area, low-cost, thin, flexible sheets creates many new possibilities. A review is presented of some of the applications of pyroelectric polymers in measurement devices View full abstract»

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  • Electrical properties of electrode/polyethylene/electrode structures

    Publication Year: 1989 , Page(s): 403 - 408
    Cited by:  Papers (35)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (356 KB)  

    The pressure-wave propagation (PWP) method allows for the nondestructive measurement of charge distributions in dielectric materials. This method has been used to study the electrical properties of electrode/polyethylene/electrode structures such as those involved in high-voltage cables. The influence of the composition of the insulating resin itself and that of the electrodes are analyzed in poly... View full abstract»

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  • The trapping of electrons in polystyrene

    Publication Year: 1989 , Page(s): 413 - 418
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (372 KB)  

    The trapping of electrons in polystyrene has been studied, using an electron beam to inject a short pulse of charge into the free surface of the thin polymer film and a second electron beam to monitor the surface potential of the film. The surface potential is proportional to trapped charge density, and the time-derivative of this potential is a measure of the current flow, which is proportional t... View full abstract»

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  • A sensor array for human-body detection based on pyroelectric polyvinylidene fluoride

    Publication Year: 1989 , Page(s): 469 - 472
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (228 KB)  

    The pyroelectric polymer polyvinylidene fluoride (PVDF) is particularly suitable for sensor arrays because of its low lateral heat flow. Sensor arrays can be used to determine the direction and, knowing the distance between detector and heat source, the velocity of a heat source. An IR detector based on PVDF is presented in which a sensor array is combined with a suitable optical unit and an ampli... View full abstract»

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  • Thermally-stimulated conductivity and luminescence in organic polymers

    Publication Year: 1989 , Page(s): 523 - 531
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (680 KB)  

    Emerging trends in the interpretation of measurements of thermally stimulated conductivity (TSC), depolarization (TSD), and luminescence (TSL) in organic polymers are reviewed, in the context of charge trapping and transport. Particular attention is given to the following: (1) the advantage of making simultaneous measurements of TSL and either TSC or TSD on the same sample, (2) the determination o... View full abstract»

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  • Space-charge distributions in electron-beam charged Mylar and Kapton films

    Publication Year: 1989 , Page(s): 533 - 536
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (240 KB)  

    Electron-beam charging and polarization of polymer films is one method used to make electrets for microphones and other devices. Insight into charge location, magnitude, and polarity can lead to a better understanding of storage and transport mechanisms in polymer films. The laser-induced pressure pulse (LIPP) method was used to determine space-charge distributions in 22-μm Mylar and Kapton fil... View full abstract»

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  • Space charge formation related to the morphology of polymers

    Publication Year: 1989 , Page(s): 419 - 423
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (360 KB)  

    The technique of thermally stimulated depolarization current measurements (TSD) was used successfully to investigate temperature-dependent space-charge formation of nonpolar polymers. In polypropylene sheet samples, the relaxation peak at crystallite melting temperature is related to the separation of stored charge carriers from the helix molecules forming the crystalline phase. The method of ther... View full abstract»

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  • Effect of crystallinity on charge storage in polypropylene and polyethylene

    Publication Year: 1989 , Page(s): 409 - 412
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (200 KB)  

    The improvement of charge storage with annealing, the use of different cooling rates, and stretching in polypropylene (PP) and polyethylene (PE) is discussed. In annealed PP and PE storage increases linearly with both crystallinity and crystallite size. The half-value charge decay temperature can be used as a measure of the latter parameters. Annealing and cooling rate affect the rate of crystalli... View full abstract»

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  • Determination of temperature distribution in single- and double-side metallized electret films

    Publication Year: 1989 , Page(s): 517 - 522
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (364 KB)  

    The well-known thermal-pulse technique is based on the temporal change of the temperature distribution in an electret sample. The resulting nonuniform thermal expansion in the sample volume leads to an electrical signal that contains information on the charge or polarization profile. A new method is proposed in which known charge profiles (e.g., electron-beam-deposited charge layers) serve as prob... View full abstract»

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  • Directional trapping

    Publication Year: 1989 , Page(s): 425 - 428
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (216 KB)  

    The concept of directional trapping, advanced by V. Adamec and J.H. Calderwood (1981), is developed in a model allowing the (approximate) calculation of its effect on the current. Carriers, drifting by the action of the field, reach (planar) dispersed obstacles on which they stick, but they are able to move again if the field is reversed. A simplified calculation is carried out attempting to expla... View full abstract»

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  • PVDF hydrophone for the measurement of shock waves [lithotripsy]

    Publication Year: 1989 , Page(s): 499 - 502
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (204 KB)  

    Focused fields of finite-amplitude ultrasonic pulses occurring in lithotripsy can be measured with hydrophones made of the piezoelectric polymer polyvinylidene fluoride. Extreme requirements for the hydrophones-peak pressure of more than 20 MPa with a risetime of less than 50 ns (shock pulses)-lead to a special construction of the hydrophone where sensitive area and metal electrodes are well separ... View full abstract»

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  • Thermally stimulated discharge current studies of corona-charged Tefzel

    Publication Year: 1989 , Page(s): 489 - 494
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (356 KB)  

    Thermally-stimulated-discharge current (TSDC) of corona-charged Tefzel has been studied. The activation energy of the trapping carriers was observed to increase with increasing charging voltage. The activation energy for the positively charged Tefzel was observed to be greater than that for the negatively charged samples. The behavior of the TSDC thermogram was found to be dependent on the anneali... View full abstract»

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  • TSDC and TSPC due to polarization by space charge migration over macroscopic distances

    Publication Year: 1989 , Page(s): 481 - 488
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (312 KB)  

    Most of the space charge in an electret is supposed to stay near its surface. The authors used two methods of investigating the charge near the surface of a polymer electret. One is the removal of a thin layer from the surface. The thermally stimulated depolarization current (TSDC) of such an electret is far smaller than before the removal. The other experiment is an investigation of stacked elect... View full abstract»

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  • Subminiature silicon integrated electret capacitor microphone

    Publication Year: 1989 , Page(s): 495 - 498
    Cited by:  Papers (14)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (276 KB)  

    Microphones were prepared that use one silicon wafer to support a thin polyester diaphragm and a second to carry a Teflon or silicon dioxide electret. Subassemblies are diced from the wafer and bonded together to form complete microphones. The preamplifier circuit can be carried on either subassembly. Microphones with reasonable signal-to-noise ratios can be obtained with edge dimensions of 3 mm o... View full abstract»

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  • Piezoelectricity and pyroelectricity in polymers

    Publication Year: 1989 , Page(s): 375 - 394
    Cited by:  Papers (27)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1200 KB)  

    Piezoelectric properties of polymeric substances arise from either the poling-induced orientation of molecular dipoles (class 1) or the uniaxial orientation of chiral chain molecules (class 2). The class 1 polymers include ferroelectric polymers, polar polymers with frozen-in dipole orientation, and the composites of polymers with ferroelectric ceramics. Details of the poling procedure in represen... View full abstract»

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  • Polarization distributions in isotropic, stretched or annealed PVDF films

    Publication Year: 1989 , Page(s): 541 - 545
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (256 KB)  

    The time development of the polarization distribution across the film thickness in polyvinylidene fluoride (PVDF) was observed using the pressure step response technique. The crystallite phase composition of the samples was changed by annealing and stretching at elevated temperatures. It is shown that the crystallite phase composition, e.g., the β crystallite content, determines the spatial d... View full abstract»

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  • Characterization of ultrasonic transducers

    Publication Year: 1989 , Page(s): 473 - 480
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (452 KB)  

    A systematic approach in the design and evaluation of high-frequency piezoelectric transducers is presented. The transducers, prior to manufacture, are modeled to generate an optimum response for a given specification. The design parameters are adjusted until a physically realizable model of the transducer is achieved. The model of the transducer is then constructed and characterized both in the t... View full abstract»

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  • Sub-Tg relaxation in cold-drawn polymers: thermally-stimulated-current methods

    Publication Year: 1989 , Page(s): 429 - 438
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (576 KB)  

    Thermally stimulated depolarization current (TSDC), thermally stimulated polarization current (TSPC), and differential scanning calorimetry (DSC) methods have been used to study the intermediate relaxation induced in glassy polycarbonate (PC) by uniaxial cold-drawing at various drawing ratios, rates, and temperatures (below the glass transition temperature Tg). A well-defined &... View full abstract»

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  • Dynamics of polarization growth and reversal in PVDF films

    Publication Year: 1989 , Page(s): 461 - 468
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (472 KB)  

    Measurements are presented of the time development of the dielectric displacement and the remanent polarization in polyvinylidene fluoride (PVDF) for poling times ranging from 1 μs to 1000 s and poling fields between 0.8 and 2.0 MV/cm. For longer times (0.1 to 1000 s), the time dependence of the polarization distribution across the film thickness is also determined. After application of a steep... View full abstract»

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  • Charge storage in dielectrics

    Publication Year: 1989 , Page(s): 395 - 402
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (508 KB)  

    Work on charge storage processes in dielectrics performed over the past few years is reviewed. Results obtained on polymers with corona, electron-beam, and pressure-pulse methods and pertaining to trap filling, spatial distribution of the charge, radiation-induced conductivity, and dynamics of the charge decay are discussed. The generation of a variety of polarization distributions in polyvinylide... View full abstract»

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  • Opto-ferroelectric memories using vinylidene fluoride and trifluoroethylene copolymers

    Publication Year: 1989 , Page(s): 537 - 540
    Cited by:  Papers (3)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (256 KB)  

    It is shown how ferroelectric polymers can be applied to an erasable optical memory. The medium developed consists of a dye-doped vinylidene-fluoride-trifluoroethylene copolymer film with a thickness of 2 μm, spin-coated onto an ITO-coated glass plate. Information is written in terms of sequences of positive and negative polarizations generated by irradiating a focused laser beam of ~5-μm di... View full abstract»

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  • Contribution of defects to the ferroelectric to paraelectric phase transition in polyvinylidenefluoride trifluoroethylene copolymers

    Publication Year: 1989 , Page(s): 443 - 448
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (316 KB)  

    X-ray techniques have been used to study the ferroelectric-to-parametric phase transition in polyvinylidene fluoride trifluoroethylene copolymers. Thermal cycles for copolymers with 20 to 40 mol% trifluoroethylene are presented. Clear evidence of anchoring, memory, and relaxation effects has been shown. These effects could be related to mobile defects present in the copolymer View full abstract»

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  • Nonlinear piezoelectricity in oriented films of PVDF and its copolymers

    Publication Year: 1989 , Page(s): 457 - 460
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (208 KB)  

    The nonlinear Piezoelectric constant for the stretched and poled films of polyvinylidene fluoride (PVDF) and (75/25) copolymer of vinylidene fluoride and trifluoroethylene has been determined by measuring the second harmonic component of polarization under sinusoidal stress. The constant increased above the glass transition temperature. A simple interpretation for the mechanism of nonlinear piezoe... View full abstract»

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  • Anomalous discharge current in copolymers of vinylidenefluoride and trifluoroethylene

    Publication Year: 1989 , Page(s): 449 - 455
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (416 KB)  

    Charge and discharge processes were studied for copolymers of vinylidene fluoride (VDF) and trifluoroethylene (TrFE) with TrFE content of 27 to 63 mol.% by use of a step-voltage field. Unlike the ordinary charge and discharge processes in polymer dielectrics, anomalous behavior was observed for copolymers of VDF and TrFE with varied comonomer content in which a current peak took place in a dischar... View full abstract»

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Aims & Scope

This Transactions ceased production in 1993. The current retitled publication is  IEEE Transactions on Dielectrics and Electrical Insulation.

Full Aims & Scope