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  • 1
    Electronic Resource
    Electronic Resource
    Bingley : Emerald
    International journal of clothing science & technology 13 (2001), S. 87-105 
    ISSN: 0955-6222
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In heavy industrial sewing, needle heating has become a serious problem that limits the further increase of the sewing speed, and hence the productivity. The high temperature in the needle can degrade the strength of the thread. At the same, it may cause the wear of the needle eye, which would further damage the thread. It can also scorch the fabric, as well as temper and weaken the needle itself. Therefore, it is important to develop a model that can predict the needle heating and, hence, find remedies to minimize its effects. According to a literature survey, most research on needle heating focuses on experimental methods, such as infrared radiometry, infrared pyrometry, etc. This paper is the first part of our research on needle heating. In this paper, two analytical models are presented: the sliding contact model and the lumped variable model. These models are relatively simple and easy to use. Given needle geometry, sewing condition, and fabric characteristic, they can predict the needle temperature rise starting from initial heating to steady state. The simulation results are rather accurate. Hence, the models can be used to quickly identify the potential needle heating problems on the shop floor. In Part 2 of our study, a finite element analysis (FEA) model is presented together with the experiment results.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physica B: Physics of Condensed Matter 161 (1989), S. 260-268 
    ISSN: 0921-4526
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physica B: Physics of Condensed Matter 159 (1989), S. 111-128 
    ISSN: 0921-4526
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 5710-5712 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Low temperature hysteresis measurements, performed on a series of Er/Y superlattices with Er interlayer thickness ranging from 37 to 90 A(ring), suggest the existence of intermediate spin states that are stabilized in a field. While bulk Er becomes ferromagnetic at 20 K, even at 10 K these samples transform to a state carrying (1)/(7) the saturation moment. This state, which is observed only at high temperatures in bulk Er, is stable at 10 K to 15 kOe, beyond which the magnetization saturates. The widths of hysteresis loops associated with the low and high field transitions, respectively, are 0.5 and 2.5 kG, many times that of Er. Just below the critical field the spin structure passes through a narrow field range where the magnetization is approximately Ms/2. No such state is observed in bulk Er in zero field. This intermediate state is more apparent on reducing the field after saturation, and becomes more stable as the Er interlayer thickness is decreased. The magnetization is not found to decay appreciably when the field is held for 10 h on the Ms/2 plateau. Preliminary data on thin films also show the existence of the Ms/7 state at low temperatures, but with the range of stability decreasing with increasing Er film thickness. We discuss these phenomena in terms of modifications of the exchange interaction due to epitaxial strains.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 5170-5172 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electrical transport properties of DyAs epitaxial layers grown on GaAs have been investigated at various temperatures and at magnetic fields up to 12 T. The measured magnetoresistances show two distinct peaks at fields around 0.2 and 2.5 T which are believed to arise from the strong spin-disorder scattering occurring at the phase transition boundaries induced by the external magnetic field. An empirical magnetic phase diagram is deduced from the temperature dependence of magnetoresistance, and the anisotropic transport properties are also presented for various magnetic field directions with respect to the current flow. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 4049-4051 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Single-crystal superlattices of dysprosium and yttrium with bilayer thickness ranging from 70 to 105 A(ring) have been grown using molecular-beam epitaxy techniques. Detailed x-ray analysis of these samples shows them to be coherent structures with abrupt interfaces between the alternating layers. These superlattices differ magnetically from pure Dy with properties that show distinct dependence on the thickness of the intervening Y.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 4043-4048 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The magnetic ordering of highly perfect single-crystal multilayer films of alternate layers of magnetic Dy and nonmagnetic Y prepared by molecular beam epitaxy has been studied by neutron diffraction. Results on a series of films with Dy thicknesses of approximately 16 atomic planes (≈45 A(ring)) and Y thicknesses ranging from 10 to 22 planes have confirmed the existence of long-range helimagnetic ordering of the Dy 4f spins which is propagated through the intervening Y layers in phase coherence. The propagation vectors in both Dy and Y layers have been calculated from the wave vector of the magnetic satellites and the intensity of the bilayer harmonics. The propagation vector for Dy decreases continuously with temperature, while that in the Y is temperature independent and equal to 0.31 A(ring)−1. The nature of the ordering and the noninteger multiple of π for the phase change of the propagation wave vector across the Y, suggests that the mechanism of long-range coupling is a conduction band spin-density wave in both Y and Dy stabilized by the 4f spins of the Dy. No intrinsic ferromagnetic transition is observed due to the clamping effect of the Y layers on the Dy magnetostriction. The application of a field along basal plane directions destroys the helical order and produces a ferromagnetic state with all spins aligned along the field direction. The moment in the induced ferromagnetic state is 10 μB, while that calculated for the zero-field helical state ranges from 7.5μB to 9.5μB for different samples, suggesting a possible static disorder of some Dy spins superimposed on the intrinsic long-range helical state.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 3458-3460 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Molecular-beam epitaxy techniques have been used to prepare coherent, crystalline superlattices of erbium and yttrium. Magnetometer measurements indicate that the transition temperatures for the superlattices are significantly lower than those for bulk erbium. The first-order transition to a conical ferromagnetic state observed in Er is suppressed. The c-axis modulated phase is stable in c-axis fields up to 17 kOe, while the field dependence of the basal-plane moments differs little from bulk Er. These results suggest that the magnetoelastic energy has been altered in the superlattice samples due to lattice clamping to the substrate and at the interfaces.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 3461-3463 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Single-crystal superlattices (Erx/Yy) have been grown by molecular-beam epitaxy techniques with the c axis perpendicular to the growth plane. The magnetic structure has been determined by neutron diffraction, and demonstrates long-range order of the c-axis Ising-like Er moments extending through the "magnetically dead'' Y layers (TN superlattice ≈TN bulk), as was found for the X-Y superlattices (Dyx /Yy). The Er c-axis effective turn angles for x=13, 23, and 32 are all nearly temperature independent at ω≈2π/7, the high-temperature lock-in value in bulk Er (although it is difficult to determine if a lock-in transition occurs), with the ferromagnetic transition completely suppressed. This results from the fact that the magneto-elastic energy density, which causes ω to decrease in the bulk, is considerably reduced in the superlattices. As in bulk Er, the high-temperature sinusoidally modulated phase "squares up'' upon reducing the temperature, and this squaring is enhanced at the basal-plane ordering transition, which is at roughly half the temperature found in bulk Er. The basal-plane turn angle tends towards the low-temperature value of bulk Er, ω≈π/4, which is surprisingly different from the c axis ω.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Surface Science Letters 258 (1991), S. L703-L707 
    ISSN: 0167-2584
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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