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61.
Toshinori Kawabata Hoe I. Ling Yoshiyuki Mohri Daisuke Shoda 《Canadian Metallurgical Quarterly》2006,132(10):1354-1359
The existing design guidelines for buried flexible pipes are limited to depth up to 10?m. The increasing use of difficult terrains for infrastructure, landfills, and residential and industrial developments has prompted installation of drainage pipelines under 20–30?m high fills. This paper presents the behavior of an instrumented flexible pipe buried under a 47.1?m deep fill. For filling above 20?m, the measured vertical stress above the pipe exhibited a concave distribution, corresponding to 90 and 110% of the average vertical pressure at the center and edges of the pipe, respectively. The measured results suggest that a triangular lateral pressure distribution can lead to overly conservative and uneconomical results for high fills while Spangler’s analysis is unconservative. Based on the measured results, a revised vertical and lateral earth pressure diagram was proposed for the design of flexible pipe under high fills >20?m. This paper proposes closed-form analyses for estimating the moments and displacements of the pipe subjected to high fill earth pressures. These closed-form solutions agree well with the measured pipe displacements and strains. 相似文献
62.
The electronic structures of polyfluoroacetylene and polydifluoroacetylene are discussed on the basis of the tight-binding LCAO-SCF-MO calculations under the CNDO/2 approximations. A method of preparation of these polymers is also proposed. If they can be successfully prepared, they will be promising candidates for new electric conducting materials as alternatives to polyacetylene. 相似文献
63.
One difficulty in analyzing the state of filament in the dry spinning process is that in the boundary conditions required to solve the equations of mass, momentum and energy which are derived on the consideration of balance with respect to infinitesimally small element are not given a priori. The equations which include these boundary conditions in themselves are derived by considering mass, momentum, and energy balances with respect to the entire cross section of filament. These additional macroscopic equations are simplified to a great extent by assuming the flat velocity profile through the cross section of filament. Besides, in the steady state, these macroscopic equations are modified to give the equations of average solvent content, spinning tension, cross-sectional area, and average temperature. When the spinning conditions are given and the physical constants are measured for a given polymer and solvent system, it becomes possible to calculate the state of filament by solving these microscopic and macroscopic equations simultaneously without resorting to actual spinning. 相似文献
64.
An exact analysis of the dynamic problem on the thermal displacements and stresses of cylindrical shells subjected to instantaneous heating is carried out. Equations of motion for cylindrical shells, including the thermal effects, are reduced and solved by using the Fourier and Laplace transformation methods, after obtaining the temperature distribution determined from the nonstationary equation of heat conduction for a shell under a prescribed temperature field. Numerical results are presented for the thermal displacement and stresses due to the time variation together with the quasistatic ones. 相似文献
65.
The macroscopic morphology of as-prepared polyacetylene depends on the concentration of the catalyst system. At high catalyst concentration, polymerization occurs on the free surface of the catalyst solution to form a polyacetylene film which retards further polymerization because of the limited diffusion of acetylene monomer through the film. At lower concentrations, however, successive diffusion and polymerization is possible yielding a gelatinous mass. A continuous mass does not form at an extremely low concentration; the product is flock or powder. Despite these differences in macroscopic morphology, electron micrographs show that the fibrillar structure is a common feature of all forms of polyacetylene. However, the average fibril diameter of 200 Å may depend on the polymerization conditions. Orientation of the fibrils by combined mechanical and thermal treatment is possible to produce highly stretch-aligned films which show anisotropic properties. 相似文献
66.
Iwaguchi S Suzuki M Sakai N Nakagawa Y Magee PT Suzuki T 《Yeast (Chichester, England)》2004,21(8):619-634
Electrophoretic karyotype studies have shown that clinical isolates of Candida albicans have extensive chromosome length polymorphisms. Chromosome translocation is one of the causes of karyotypic variation. Chromosome translocation events have been shown to occur very frequently at or near the major repeat sequence (MRS) on chromosomes. The MRS consists of the repeated sequences RB2, RPS and HOK, and the repeated sequences are considered to be the template for recombination. To investigate which element of the MRS is important for chromosome translocation, we constructed three cassettes, each containing a URA blaster and sequences homologous to one of the repeats, for insertion into the MRS region on the chromosomes. The ura3 strain STN22u2, which shows a stable, standard karyotype, was transformed with each construct. Insertion events with each cassette occurred at almost all chromosomes. Insertion into the RB2 repeat, but not into the RPS repeat, was accompanied by chromosome translocation in some transformants: chromosome translocations between chromosomes R and 7 and chromosomes 1 and 7 were found, as well as deletions of 7A and 7C from chromosome 7. We conclude that the insertion at the RB2 region may initiate chromosome translocation in C. albicans. 相似文献
67.
Diversity control in ant colony optimization 总被引:1,自引:0,他引:1
Optimization inspired by cooperative food retrieval in ants has been unexpectedly successful and has been known as ant colony
optimization (ACO) in recent years. One of the most important factors to improve the performance of the ACO algorithms is
the complex trade-off between intensification and diversification. This article investigates the effects of controlling the
diversity by adopting a simple mechanism for random selection in ACO. The results of computer experiments have shown that
it can generate better solutions stably for the traveling salesmen problem than ASrank which is known as one of the newest and best ACO algorithms by utilizing two types of diversity. 相似文献
68.
Hiromi?YoshidaEmail author Kyoko?Matsuda Yuki?Hirakawa Yoshiyuki?Mizushina 《Journal of the American Oil Chemists' Society》2003,80(7):665-674
To clarify the effects of microwave roasting on the distribution of tocopherols and FA of phospholipids within soybeans, whole
soybeans (Glycine max) were treated by microwave and further evaluted as compared to a raw sample. Tocopherol homologs, measured using HPLC, and
phospholipid profiles, quantified with GC, were determined in the seed coat, the embryonic axis, and selections of cotyledons
separated from three cultivars. The tocopherols were predominantly detected in the axis, followed by the cotyledons, and then
very little in the coat. As much as 25% of the individual tocopherols originally present in the coat were lost at 12 min of
roasting, whereas <25% was lost in the cotyledons and the axis after 20 min of roasting. The greatest rate of phospholipid
loss (P<0.05) was observed in PE, followed by PC and PI, and their changing patterns were more pronounced in the coat than in the
cotyledons or the axis. Thus, tocopherol content and phospholipid profiles change with microwave roasting according to tissue. 相似文献
69.
Yusuke Kusuda Kinya Fukuda Masao Matsumura Kazuhisa Hagisawa Gaku Okamoto Tatsuo Nakanishi Yoshiyuki Inoue 《Electrical Engineering in Japan》2007,159(4):18-26
Recently, composite insulators have been increasingly employed mainly for economic reasons. We have developed a new type of outdoor termination using a composite insulator, which can be installed horizontally on a steel tower in order to reduce the construction cost. In this outdoor termination, SF6 gas is filled in the composite insulator and a cold shrinkable premolded rubber unit is applied instead of the combined use of a rubber‐molded stress relief cone, epoxy resin insulator and spring unit. The application of the composite insulator, SF6 gas and cold shrinkable premolded rubber unit reduces the total weight and makes it possible to install the termination horizontally on the tower. The new‐type outdoor termination for 77‐kV XLPE cable has already been applied in commercial use and enabled a reduction of the construction costs for power transmission lines. A 154‐kV new‐type outdoor termination has been developed and its initial electrical tests were successfully completed. This paper describes the design and performance of both 77‐kV and 154‐kV new‐type outdoor termination, and a follow‐up survey of the 77‐kV new termination in a commercial use. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(4): 18– 26, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20511 相似文献
70.
Mikio Fukuhara Yoshiyuki Kuwano Kiyoshi Saito Taiji Hirasawa Ichiro Komura 《NDT & E International》1998,31(3):211-216
The degree of fatigue in ferritic wrought steel during cyclic bending was determined by analysis of diffracted SH ultrasonic waves with the aid of multiple regression analysis. As the degree of fatigue increases, accompanied by residual stress, the incident waves curve to the interior region with positive stress field owing to the acoustoelastic effect. As a result, the propagation time of the launched waves lengthens, leading to a modulation of the received waveform. Multiple regression analysis for the waveform modulation produces a reliable estimation, with correlation coefficient of 0.948, for the degree of fatigue. 相似文献