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121.
By the use of a position sensitive proportional counter, changes in small and wide angle X-ray scattering during annealing of polyethylene single crystal mats were measured from the start in successive spans of very short measuring time. At high temperatures, the long period relating to stacking of lamellae rapidly increased at an early stage, passed through a plateau, and thereafter again increased gradually. With a decrease in annealing temperature, the amount of its first rapid increase was reduced and the plateau changed into an ascending slope. At much lower annealing temperatures, the long period increased following the logt law after an induction time. The integral breadth of a peak corresponding to the long period first increased rapidly, simultaneously with the rapid increase in the long period, and thereafter decreased. Wide angle X-ray measurement showed that the integrated intensity of 110 reflection first decreased and then increased during annealing at high temperatures. This fall and rise process was more marked, when the annealing temperature is higher and the initial thickness of lamellae is smaller. From these observations, it was inferred that in the thickening process, stacking order of lamellae at first decreased because of rapid reorganization due to partial melting or melt-recrystallization and subsequently increased through increasing evenness of lamellar thickness. 相似文献
122.
Radiation-induced copolymerizations of perfluorovinyl acetic acid and its methyl ester with α-olefin
Mitsuo Kawaguchi Terutaka Watanabe Osamu Matsuda Yoneho Tabata Sueo Machi 《Journal of polymer science. Part A, Polymer chemistry》1981,19(6):1525-1531
Homopolymerizations and copolymerizations of perfluorovinyl acetic acid (FVA) and its methyl ester (MFVA) were carried out by γ radiation at a temperature of 25°C, a dose rate of 1 × 106 rad/hr, and FVA/α-olefin and MFVA/α-olefin ratios of 10/90-90/10 in the monomer mixture. FVA and MFVA gave small quantities of brown and greasy low-molecular-weight homopolymers. The polymerization rates of both FVA and MFVA were extremely small, as shown by the maximum G value of monomer consumption of 12. FVA and MFVA reacted with α-olefin to form waxlike copolymers. The copolymerization rates of both FVA and MFVA with α-olefin were remarkably larger than those of the homopolymerizations, particularly with ethylene. The polymer compositions of FVA/ethylene or MFVA/ethylene was nearly 1/2 over a wide range of the monomer compositions. The Mayo–Lewis method gave negative r1 (FVA) and r1 (MFVA). The polymer composition curves could be well interpreted by introducing the penultimate model. 相似文献
123.
Takahiro Tsukahara Yusuke Sakamoto Daisuke Aoshima Makoto Yamamoto Yasuo Kawaguchi 《Experiments in fluids》2012,52(4):877-890
The installation of windbreak sand fences around sand dunes is one of the most promising methods to suppress windblown sand
movement. In the study reported in this paper, we investigated the influence and validity of a small fence mounted on a model
sand dune, in order to understand the fence’s suppression mechanism on the sand movement. The flow field around the dune and
the process of sand-dune erosion were measured using LDV, PIV, and laser-sheet visualization techniques. A non-porous fence
was found to suppress sand movements in its upstream area, but to enhance erosion downstream of the fence. This intensive
erosion was caused by separated shear flow from the leading edge of the fence. In this study, four levels of porosity rate
of the fence were tested. The fence-porosity dependences of the turbulent flow field and the erosion were discussed. The shapes
of eroded sand dunes were found to depend on the porosity rate. The relationship between the sand-dune erosion and the flow
field around the dune was illustrated with schematic diagrams. We concluded that the most desirable fence porosity should
be 30% in order to avoid dune erosion if installed at a middle height on the stoss surface of a dune. This porosity provides
a mean velocity reduction with avoiding a separated flow, although the flow bleeding through the porous fence is accompanied
by grid turbulence and induces serious erosion in a narrow space behind the fence. Furthermore, we confirmed that the empirical
correlation of the critical friction velocity can be applied to sand movements influenced by a fence. 相似文献
124.
Pristine and iodinated (SN)x were studied by high resolution electron microscopy. High resolution electron micrographs showing lattice fringes up to 0.22 nm were obtained. In these electron micrographs, the texture of (SN)x crystals was elucidated to be fibrillar or mosaic; the lattice fringes were observed in domains extended along the molecular axis (b-axis) and very narrow in the perpendicular direction. Each crystallite varied from place to place in size but maintained the b-axis orientation.The high resolution image of iodinated (SN)x did not show directly the location of iodine atoms and their presence was deduced only from the optical transform of the image. The optical transform showed that iodine atoms were not intercalated uniformly, but localized at the skin region on (SN)x fibers, where the crystal lattice was highly distorted. Then the iodination of (SN)x is supposed to result in the destruction of the crystal lattice by invasion of iodine atoms or to take place preferentially at a distorted crystal region. 相似文献
125.
Masataka Ihara Tomoko Kirihara Akihiro Kawaguchi Keiichiro Fukumoto Tetsuji Kametani 《Tetrahedron letters》1984,25(40):4541-4544
Intramolecular Diels-Alder reaction of l-azadienes was conducted by heating the α,β-unsaturated amides (2a ~ d and 6) in the presence of trimethyl- chlorosilane, triethylamine and zinc chloride to give benzo- and indolo[a]- quinolizidines (5a ~ e and 7). 相似文献
126.
Noriya Okanouchi Hidehiro Honda Rie Ito Migaku Kawaguchi Koichi Saito Hiroyuki Nakazawa 《Analytical sciences》2008,24(5):627-630
In this study, a fast, simple and highly sensitive method that employs liquid phase microextraction (LPME)-GC/MS was developed to analyze trace benzophenones (BPs) in river-water samples. The tip of a 10-microl microsyringe filled with toluene (3 microl) was inserted into 2 ml of a river-water sample, and fixed at 5 mm below the water surface of the sample. A toluene droplet was made on the tip of the syringe, and extraction was conducted while agitating at 500 rpm for 15 min. After extraction, 2.0 microl of the extract was put into the syringe again, and directly introduced to GC/MS. The limits of detection (S/N = 3) and quantification (S/N >10) of BPs were 10 and 50 pg ml(-1), respectively. The results of a recovery test ranged over 93.3 - 101.1% (RSD, less than 10%; n = 6). The results of BPs determinations in the river-water samples showed that BPs (ND - 68.9 pg ml(-1)) were detected. 相似文献
127.
R Shimazawa Y Ogawa N Morisaki H Funabashi A Kawaguchi S Iwasaki 《Chemical & pharmaceutical bulletin》1992,40(11):2954-2957
2,3-Epoxy-4-hydroxy-4-((E,E)-3,6-octadienyl)cyclopentanone (dl-carbacerulenin 5) was synthesized via the epoxyketones 15a and 15b as a mimic of the active form of the antibiotics cerulenin 1, a potent inhibitor of fatty acid synthetase (FAS). The monobenzyl ethers (12 and 13), synthetic intermediates of 15, were prepared by direct benzylation of the epoxycyclopentene (7). Inhibitory activity of synthesized 5 toward yeast FAS was less than that of cerulenin by a factor of 1000. 相似文献
128.
129.
Masataka Hiraide Yuichi Ohta Hiroshi Kawaguchi 《Analytical and bioanalytical chemistry》1994,350(10-11):648-650
Positively charged alumina surfaces were coated with sodium dodecyl sulfate, into which 1-nitroso-2-naphthol was immobilized. The alumina particles were effectively used for the collection of nanogram amounts of cobalt(II) from aqueous solutions of pH 1–2.5. The method has been applied to the electrothermal AAS determination of cobalt in high-purity zinc metal. 相似文献
130.