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1.
Toshihiko Kujime Soong-Keun Hyun Hideo Nakajima 《Metallurgical and Materials Transactions A》2006,37(2):393-398
A lotus-type porous carbon steel with cylindrical pores was fabricated by the continuous zone melting method in a pressurized
mixture of hydrogen and helium gases. The porosity increases with increasing partial pressure of the hydrogen gas, while the
pore diameter remains almost constant, independent of the pressure. The ultimate tensile strength of the specimen with cylindrical
pores parallel to the tensile direction is lower than the estimated value, assuming that the strength is decreased in proportion
to the decrease of the cross-sectional area of the specimen, while the yield strength is higher than the estimated value.
The compressive yield strength is also higher than the estimated value. The increase in yield strength is considered to be
due to precipitation strengthening. The tensile strength is increased by quenching and tempering, while the elongation decreases.
Such mechanical properties are discussed in terms of the microstructural analysis. 相似文献
2.
Hideo Sawada Hiroshi Kakehi Masashi Koizumi Yoshihiro Katoh Masashi Miura 《Journal of Materials Science》2007,42(17):7147-7153
Fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomer [RF-(DOBAA)
n
-RF] reacted with tetraethoxysilane (TEOS) and silica nanoparticles in the presence of low-molecular weight biocides such as
hibitane, hinokitiol, and hinokioil under alkaline conditions to afford RF-(DOBAA)
n
-RF/silica nanocomposites-encapsulated these biocides in excellent to moderate isolated yields. Fluoroalkyl end-capped N,N-dimethylacrylamide oligomer [RF-(DMAA)
n
-RF] and acrylic acid oligomer [RF-(ACA)
n
-RF]/silica nanocomposites-encapsulated hibitane were obtained under similar conditions. Dynamic light scattering measurements
showed that the size of these fluorinated nanocomposites-encapsulated biocides thus obtained is nanometer size-controlled.
Additionally, these fluorinated nanocomposites were shown to have a good dispersibility and stability in methanol and water.
Of particular interest, these fluorinated nanocomposites-encapsulated biocides were found to have a good antibacterial activity
against Staphylococcus aureus, and these nanocomposites were applied to the surface modification of traditional organic polymers such as poly(methyl methacrylate). 相似文献
3.
This study was performed in order to clarify crack opening displacement (COD) of through-wall cracks in a plate subjected to bending load. The former COD evaluation methods were mainly developed corresponding to tensile load, but there has been nothing that has been developed corresponding to bending load. Therefore, the authors evaluated CODs of the through-wall cracks in plates which were subjected to a bending load using finite element method (FEM) analyses, and proposed a simplified COD evaluation method accounting for both tensile and bending loads. The proposed method is useful for leakage evaluation at a crack opening of an elbow crown or in the vicinity of the coolant surface of a vessel in which the bending stress is relatively large. 相似文献
4.
Yuji Oie Tatsuya Suda Masayuki Murata Hideo Miyahara 《International Journal of Satellite Communications and Networking》1991,9(5):285-303
One of the most promising approaches for high speed networks for integrated service applications is fast packet switching, or ATM (asynchronous transfer mode). ATM can be characterized by very high speed transmission links and simple, hard-wired protocols within a network. To match the transmission speed of the network links, and to minimize the overhead due to the processing of network protocols, the switching of cells is done in hardware switching fabrics in ATM networks. A number of designs have been proposed for implementing ATM switches. Although many differences exist among the proposals, the vast majority of them are based on self-routeing multistage interconnection networks. This is because of the desirable features of multi-stage interconnection networks such as self-routeing capability and suitability for VLSI implementation. Existing ATM switch architectures can be classified into two major classes: blocking switches, where blockings of cells may occur within a switch when more than one cell contends for the same internal link, and non-blocking switches, where no internal blocking occurs. A large number of techniques have also been proposed to improve the performance of blocking and non-blocking switches. In this paper, we present an extensive survey of the existing proposals for ATM switch architectures, focusing on their performance issues. 相似文献
5.
Bhupesh C. Roy Motonobu Goto & Tsutomu Hirose 《International Journal of Food Science & Technology》1996,31(2):137-141
Tomato seed oil was extracted with supercritical carbon dioxide in a semibatch-flow extractor within the temperature range 313–343 K and the pressure range 10.8–24.5MPa. The extraction rates increased with pressure, but decreased with temperature increase because of the variation in solvent density and resultant differences in oil solubility. The fatty acid composition of the extracted oil was similar to that of soybean oil. 相似文献
6.
Brushless three-phase synchronous motor involving a rotating ac exciter on the same shaft as the motor and with the windings linked through a shaft-mounted rectifier is widely used as medium and large capacity machines. However, the motor needs to fit with damping windings for self-starting outside of the field winding in the rotor and needs to equip discharge resistance with complex electronic device to dispose of electromagnetic force induced in the field winding at starting. Therefore, the rotor structure is very complex, and there are disadvantages, especially for the robust and highly reliable motor that is desired. To solve the problem found in traditional motors, the authors proposed a brushless three-phase synchronous induction motor with two stators and one wound rotor. This problem is solved because the proposed motor is of two-stators structure: the rotor winding operates as a secondary winding of induction motor at starting and as the field winding at synchronous operation. The motor can self-start as a wound-rotor induction motor without external secondary resistance. Therefore, discharge resistance is not necessary; the starting equipment is very simple and the rotor structure is robust. It is possible to start with high torque. In this paper, the basic constitution of the proposed motor and the principles of operation are described in detail. The experimental results at starting and pulling into synchronism are shown for confirming the principles of operation and the experimental and numerical results of the starting characteristics. The load ones and the generating ones are shown and then the practical use of the proposed motor is confirmed. 相似文献
7.
Sh ichi sawa Eiji sawa Yü ji Hirose 《Fullerenes, Nanotubes and Carbon Nanostructures》1995,3(5):565-585
Initial steps of thermal transformation from doubly bonded [2+2] (1) and [4+4] (2) dimers of C60 have been analyzed on the basis of computed structural features and Pople's energy partition scheme. Completely conjugated C120 structures 3 and 4 are found to be considerably stable and proposed to be important intermediates. The linkage patterns in 3 and 4 are also likely to appear in the repeating units of the metastable dimer and polymer phases of A1 crystals. 相似文献
8.
The present paper deals with the finite element analysis of two-dimensional two-layer density flows in a gravitational field. A fluid in each layer is replaced with a large number of discrete particles, and the motion and deformation of each layer is represented by moving those particles in a Lagrangian manner. The velocity distribution in the whole fluid region is given as the finite element solution of the Navier-Stokes equations and the equation of continuity. In the finite element calculation, free-slip conditions are used on solid wall boundaries because no-slip conditions may cause sticking of some particles to walls. Then, a new technique for the implementation of free-slip conditions on arbitrary curved boundaries is presented. As numerical examples, density flows in a rectangular closed container and Rayleigh-Taylor instability in the container with a circular cross-section have been computed. 相似文献
9.
BACKGROUND: Increases in acetylcholine receptors (AChRs) at the muscle membrane, induced by burn injury, have been associated with a hyperkalemic response to succinylcholine and resistance to d-tubocurarine-like drugs. Muscle relaxants often are administered to burn-injured patients in the intensive care unit to facilitate mechanical ventilation. This study in rats tested whether continuous administration of d-tubocurarine in subparalytic doses exaggerates the upregulation of AChRs induced by burn trauma. Subparalytic doses were used to avoid the confounding effects of immobilization. METHODS: Three days after an approximate 50% body surface area burn or sham injury, the animals received an infusion of 3.03 +/- 0.05 micrograms/h of d-tubocurarine or equal volume of saline directly to the left gastrocnemius muscle via catheter connected to a subcutaneously implanted osmotic pump. After 7 days of d-tubocurarine or saline infusion, the AChRs were quantitated using 125I-alpha-bungarotoxin. The AChRs on the d-tubocurarine or saline-infused left gastrocnemius were compared to the contralateral gastrocnemius in the same group. The right or left gastrocnemius AChRs were compared to the ipsilateral muscles between groups. These intra- and intergroup comparisons allowed the delineation of the effects of catheter irritation, burns, or d-tubocurarine on AChRs. RESULTS: Daily examination of the withdrawal response to toe-pinch revealed no evidence of paralysis. Weight loss in the burn-injury animals receiving d-tubocurarine or saline was similar, confirming that the infusion of d-tubocurarine did not impair the mobility of the animals to move and feed. The plasma d-tubocurarine concentration after 7 days of infusion was 26.0 +/- 12 ng/ml (mean +/- SE). Regardless of burn or sham injury or of d-tubocurarine or saline infusion, the concentration of AChRs on the left was consistently greater than in the contralateral right gastrocnemius muscles within the same group, indicating that manipulation of the area alone can result in upregulation of AChRs. The AChRs in the right gastrocnemius of burn-injured animals were greater than those in the same muscle of sham-injured animals, regardless of saline (7.24 +/- 0.9 vs. 5.7 +/- 0.5 fmoles/mg protein, P = 0.06) or d-tubocurarine (7.3 +/- 0.4 vs. 5.7 +/- 0.5, P < 0.05) infusion to the burn-injury groups. AChRs in the left gastrocnemius of burn-injury animals receiving d-tubocurarine were significantly greater than those in burn- or sham-injury animals receiving saline (13.9 +/- 1.1 vs. 9.8 +/- 1.2 and 7.1 +/- 0.5 fmoles/mg protein, respectively, P < 0.05). CONCLUSIONS: Burn-induced upregulation of AChRs is accentuated by infusion of subparalytic doses of d-tubocurarine. Concomitant administration of d-tubocurarine to burn-injured patients may result in further exaggeration of the aberrant responses to neuromuscular relaxants. 相似文献
10.
Tatsuro Kijima Kouji Ohshima Hideo Kise 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1994,59(1):61-65
Racemic amino acid esters were optically resolved via hydrolysis in organic solvents by the catalysis of an industrial alkaline protease, “Alcalase”. The products which were composed mainly of L-amino acids were insoluble and easily separated by filtration. The activity of the enzyme and enantiomeric excess of the products were significantly dependent on the nature of solvent and the water content in the reaction media. Generally, high values of enantiomeric excess were obtained at low water contents. Many natural and unnatural amino acids were resolved by this method. 相似文献