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61.
In order to prepare the functional and fine powdery polymer, glycidyl methacrylate (GMA) and divinylbenzene (DVB) were polymerized in cyclohexane. This polymerization was heterogeneous. In the time–conversion curve, an autoaccelerating phenomenon and an apparently steady state were observed, and the activation energies for both reactions in the earlier stage and the steady state were calculated to be 28 kcal/mole and 11 kcal/mole, respectively. It is especially noteworthy that the increase in the DVB concentration decreased the polymerization rate. The diffusion of the monomers through the polymer matrix should be one of the most important factors. Some properties of the copolymer and its application as a mordant were studied. 相似文献
62.
Nakamura E. Uchinda K. Koshiishi M. Mitsui T. Miyamoto S. Nakamura K. Itaka K. Hara T. Yoda T. 《Power Delivery, IEEE Transactions on》1986,1(1):19-26
A fault section detecting system using optical magnetic field sensors developed for gas insulated transmission lines (GIL) is reported. A bismuth silicon oxide (Bi12SiO20, or BSO) single crystal was adopted for the optical nagnetic field sensor. A method of mounting the sensors to GIL which enables the sensors to detect the conductor current from outside the enclosure was developed. With the developed fault detector, faults occurring inside a section of GIL between sensors are detected by discriminating the phases of conductor currents detected by the sensors. The system was confirmed to have sufficient performance for application to commercial GILS. 相似文献
63.
64.
An anion-exchange membrane was modified by sulfonating the surface of the base membrane, composed of styrene-divinylbenzene copolymer and polyvinylchloride, before its chloromethylation and the subsequent quarternization. The following three points are discussed: (1) effect of surface treatment with concentrated sulfuric acid to protect the membrane against organic fouling, (2) relation between sulfonating conditions at the membrane surface and the properties of the modified anion-exchange membrane, and (3) evaluation of the modified anion-exchange membrane. 相似文献
65.
Hiroki Adachi Wataru Itaka Tetsuo Aida K. Osamura Manabu Imaoka Jun Kusui 《Transactions of the Indian Institute of Metals》2009,62(2):163-167
Heat-resistant aluminum alloys are generally developed by dispersing stable intermetallic compounds by adding transition metals
(TM) whose diffusion coefficient in aluminum alloys is low even at high temperatures. Commonly used intermetallic compounds
include Al-TM binary intermetallic compounds, for example, Al6Fe, Al3Ti and Al3Ni. By contrast, multicomponent intermetallic compounds are hardly used. The present study focuses on Al-Mn-Cu and Al-Mn-Ni
ternary intermetallic compounds, and by finely dispersing these intermetallic compounds, attempts to develop heat-resistant
alloys. Through the atomization method, Al-(4.96–5.96)Mn-(6.82–7.53)Cu-0.4Zr and Al-(5.48–8.76)Mn-(2.23–4.32)Ni-0.4Zr (in
mass%) powders were fabricated, and by degassing these powders at 773 K, intermetallic compounds were precipitated. These
powders were then solidified into extrudates by hot extrusion at 773 K. The microstructural characterization of powders and
exrudates was carried out by XRD analysis, SEM/EDX and TEM. The mechanical properties of extrudates were determined at room
temperature, 523 K and 573 K. In Al-Mn-Cu alloys, while a small amount of Al2Cu was crystallized, precipitated Al20Mn3Cu2 intermetallic compounds were mainly dispersed. In Al-Mn-Ni alloys, while a small amount of Al6Mn intermetallic compounds was precipitated, the precipitated A60Mn11Ni4 intermetallic compounds were mainly dispersed. Both ternary intermetallic compounds were about 200 nm in size. The compounds
were elliptical, and their longitudinal direction was oriented along the extrusion direction. In the Al-Mn-Cu alloys, since
the work hardening at room temperature was high, the tensile strength became 569 MPa. At elevated temperatures, since hardly
any work hardening was observed, the tensile strength decreased markedly. However, in Al-Mn-Ni alloys, since the work hardening
is low even at room temperature, the roomtemperature strength is not high. Thus, the decrease in tensile strength at elevated
temperatures is relatively small and a high strength was obtained at 523 K and 573 K: 276 MPa and 207 MPa, respectively. 相似文献
66.
67.
Most materials expand upon heating. However, although rare, some materials contract upon heating. Such negative thermal expansion (NTE) materials have enormous industrial merit because they can control the thermal expansion of materials. Recent progress in materials research enables us to obtain materials exhibiting negative coefficients of linear thermal expansion over −30 ppm K−1. Such giant NTE is opening a new phase of control of thermal expansion in composites. Specifically examining practical aspects, this review briefly summarizes materials and mechanisms of NTE as well as composites containing NTE materials, based mainly on activities of the last decade. 相似文献
68.
69.
High-precision ball bearings (SUS440C) used in spacecraft mechanisms that are exposed to deep space vacuum are solid lubricated by thin, adherent Pb ion-plated coatings. The high reliability requirements with long endurance life of these mechanisms solely depend on the tribological aspects of this solid-lubrication coating. Since ion-plated, soft metallic coatings have a graded coating–substrate interface structure, a gradual change in mechanical, chemical and thermal properties is expected across the depth of the coating. This aspect of the interlayer plays a major role in determining the extent of optimum tribological properties of the coating. By improving the interlayer, both in terms of increased thickness and concentration of Pb, a corresponding improvement in the lubricity and endurance life of this Pb ion-plated coating on AISI 440C stainless steel (bearing material) can be assured. For this, a detailed examination of the interlayer of the ion-plated Pb film on the nano-micro level is mandatory. This report is focused on the cross-sectional examination of the interlayer by scanning electron microscopy. SUS440C steel disk specimens having similar properties as the bearing material and with a thin, ion-plated Pb coating processed under two different substrate bias conditions of ion-plating are used. The thickness of the Pb/steel interlayer and the elemental composition are analyzed using SEM and EDS respectively. The endurance life of the coatings is measured by repeated sliding wear tests with a pin-on-disk tester in vacuum. It is confirmed that with an increased thickness of the graded interfacial layer of the Pb ion-plated coating, the coating endurance life is extended remarkably. 相似文献
70.