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  • 1
    Electronic Resource
    Electronic Resource
    Analog frequency modulation detector for dynamic force microscopy (2001)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 72 (2001), S. 4383-4387 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new analog frequency modulation (FM) detector (demodulator) for dynamic force microscopy (DFM) is presented. The detector is designed for DFM by utilizing the FM detection method where the resonance frequency shift of the force sensor is kept constant to regulate the distance between a tip and a sample surface. The FM detector employs a phase-locked loop (PLL) circuit using a voltage-controlled crystal oscillator (VCXO) so that the thermal drift of the output signal is negligibly reduced. The PLL is used together with a frequency conversion (heterodyne) circuit allowing the FM detector to be used for a wide variety of force sensors with the resonance frequency ranging from 10 kHz to 10 MHz. The minimum detectable frequency shift was as small as 0.1 Hz at the detection bandwidth of 1 kHz. The detector can track a resonance frequency shift as large as 1 kHz. We also present some experimental results including the observations of the Si(111)-7×7 reconstructed surface and fullerene molecules deposited on the surface by DFM using this FM detector. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1416104
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  • 2
    Electronic Resource
    Electronic Resource
    Structures of vinylidene fluoride oligomer thin films on alkali halide substrate (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 3688-3693 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Structures and crystal transformation of the newly synthesized vinylidene fluoride (VDF) oligomer with large electric dipoles evaporated on KCl (001) at various substrate temperatures have been investigated by an energy dispersive–grazing incidence x-ray diffraction system, Fourier transform infrared spectroscopy, and atomic force microscope (AFM). It was revealed that the molecules grow epitaxially and are influenced greatly by forces of the crystal surface field in terms of van der Waals or electrostatic potentials, and found that the phase transformation from form II (α phase) to form I (β phase) is induced by raising the temperature of the substrate from 50 to 80 °C, accompanying the alternation in the crystal axes on the substrate from the a axis of form II to the polar b axis of the form I crystal. This fact suggests that the molecular chain of VDF oligomers aligns their c axes along the 〈110〉 row of K+ or Cl− with the aid of electrostatic interaction under enough thermal movement. Moreover, in the transformation process, a pair of "rod-like" crystals, suggesting ferroelectric activity, were observed by AFM. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371279
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  • 3
    Electronic Resource
    Electronic Resource
    Structural evaluation of epitaxially grown organic evaporated films by total reflection x-ray diffractometer (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 7338-7343 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An in-plane-type total reflection x-ray diffractometer was newly constructed, and the epitaxial growth of paraffin molecules (n-C33H68) vacuum-evaporated onto a KCl (001) surface was investigated. The molecular chains in as-evaporated films were shown to arrange themselves parallel to the 〈110〉 direction of the KCl substrate. After the evaporation, moreover, some molecules were revealed to reorient and tend to deviate their c axis by about ±5° from the 〈110〉 direction of the KCl crystal, probably because of the lattice mismatchings between the paraffin and substrate crystals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354024
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  • 4
    Electronic Resource
    Electronic Resource
    Quasi-intrinsic semiconducting state of titanyl-phthalocyanine films obtained under ultrahigh vacuum conditions (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 873-875 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We investigated electrical properties of titanyl-phthalocyanine (TiOPc) films under ultrahigh vacuum (UHV) conditions to avoid the influence of gas adsorption. The field-effect measurement revealed that TiOPc films exhibited an n-type semiconducting behavior in UHV. The electron mobility at room temperature was 9×10−6 cm2 V−1 s−1 with activation energy of 0.20 eV. The conductivity and carrier density were 9×10−8 S cm−1 and 6×1016 cm−3, respectively. A clear conversion from n-type to p-type behavior was observed when the film was exposed to oxygen. Strict control of atmosphere made it possible to obtain a quasi-intrinsic state where both p- and n-type conductions appeared simultaneously. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.125614
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  • 5
    Electronic Resource
    Electronic Resource
    Photoelectron spectra enhanced by x-ray total reflection and diffraction from periodic multilayer (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 1921-1923 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoelectron spectra from a periodic multilayer of (Mo/B4C)30/Si were measured by changing the x-ray glancing angle. The angular dependencies of the photoelectron intensities of O 1s and Mo 3d revealed the atomic depth profiles of the Mo oxide overlayer, and the compositions of the MoO3 upper layer and MoO2 lower layer. Furthermore, we observed enhancement of photoelectron emission by means of x-ray standing waves generated near the multilayer surface during x-ray diffraction from the superlattice. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115626
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  • 6
    Electronic Resource
    Electronic Resource
    Total reflection x-ray excited photoelectron spectra of copper phthalocyanine thin layer on Si wafer (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 3889-3891 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoelectron spectra of a Si wafer, on which copper phthalocyanine was evaporated with a thickness of 50 A(ring), were measured using grazing incidence x rays under a total reflection condition. It was observed that the backgrounds owing to inelastic electron scattering in solids were reduced. It was also observed that the substrate Si signal was removed and that surface signal was enhanced due to the total x-ray reflection. Oxygen depth was determined using the angle dependence of the x-ray photoelectron spectral intensity. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115307
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  • 7
    Electronic Resource
    Electronic Resource
    X-ray microanalysis and acoustic emission studies on the formation mechanism of secondary cracks in PMMA (1984)
    Springer
    Journal of materials science 19 (1984), S. 1548-1555 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The formation mechanism of secondary cracks in poly(methyl methacrylate) (PMMA) was investigated using various methods. X-ray element analysis and SEM observations on parabolic markings showed that there exist certain defects such as silicon compound and microcracks at their foci, forming the potential sources for the secondary cracks (a static factor). On the other hand, the fracture process was monitored simultaneously with acoustic emission (AE) and high speed shadow-optical techniques. These observations revealed that density of the parabolic marking has a closer correlation to the amplitude of the stress wave emitted during crack propagation, rather than to the values of crack speed or stress intensity factor (a dynamic factor). The formation mechanism is thus explained by the combination of these static and dynamic factors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00563052
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  • 8
    Electronic Resource
    Electronic Resource
    Relaxations of bisphenol A-based epoxides cured with aliphatic diamines (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 50 (1993), S. 67-73 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The main α and sub β relaxations in bisphenol A-based epoxides cured by two kinds of aliphatic diamines were examined in wide temperature and frequency ranges by using middle-frequency dynamic, dielectric, and ultrasonic measuring systems. The obtained temperature-frequency correlation maps revealed an Arrhenius-type behavior for the β relaxation with apparent activation energy of 16 kcal/mol. For the α relaxation, the maps were in good agreement with the W.L.F. equation. Owing to the similarity of structure in these resins, both maps showed the same tendencies. © 1993 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070500109
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  • 9
    Electronic Resource
    Electronic Resource
    Direct observation of phase transitions of polyethylene under high pressure by a PSPC x-ray system (1981)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 19 (1981), S. 1313-1324 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A position-sensitive proportional counter (PSPC) x-ray measuring system is employed to observe directly phase transition processes of polyethylene at high temperature and high pressure. X-ray diffraction measurements reveal important new experimental data. First, an irreversible crystal transition from the hexagonal to the orthorhombic structures occurs in the critical region where the hexagonal structure begins to appear at a pressure of 350 MPa. That is, the (100) hexagonal reflection is observed only on cooling at 350 MPa. At pressures above about 400 MPa, however, the hexagonal phase is stable and the phase transitions melt ↔ hexagonal ↔ orthorhombic occur reversibly. Second, during cooling at pressures above 400 MPa, the (100) hexagonal reflection can be observed at temperatures below the hexagonal ↔ orthorhombic transition temperature. This behavior suggests that all the crystal morphologies of polyethylene, from “highly-extended-chain” crystals to crystals with a low melting point, are formed by the transitions melt → hexagonal → orthorhombic. Third, in heating at elevated pressures above 500 MPa, a shoulder in the peak intensity versus temperature plot for the (100) hexagonal reflection is observed at a higher temperature than the large maximum which occurs immediately after the crystal transition. This behavior indicates melting in two stages of hexagonal structures with different thermal stabilities, and the shoulder at higher temperature may be due to the fusion of the hexagonal phase annealed either below or above the transition point.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1981.180190903
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  • 10
    Electronic Resource
    Electronic Resource
    Melting and crystallization of poly(vinylidene fluride) under high pressure (1978)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 16 (1978), S. 921-934 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Precise melting and crystallization temperatures of extended-chain and folded-chain crystals of form I and folded-chain crystals of form II poly(vinylidene fluoride) under high pressure have been obtained by microdifferential thermal analysis (DTA). Upon heating at pressures above 4000 kg/cm2, the micro-DTA thermogram of form II crystallized from the melt at atmospheric pressure shows melting of the form II structure and the melting of the folded-chain and extended-chain crystals of form I, formed through recrystallization processes. These features were clarified by supplemental methods. The bandwidth seen in electron micrographs of the extended-chain crystal of form I obtained by crystallization under high pressure was in the range of 1500 to 2000 Å. At atmospheric pressure, the extended-chain crystal of form I melted at 207°C, approximately 17°C higher than the folded-chain crystal of form I and 31°C higher than the folded-chain crystal of form II.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1978.180160516
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