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排序方式: 共有1394条查询结果,搜索用时 14 毫秒
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.
Kameyama H. Miyajima T. Zhi Ding 《IEEE transactions on circuits and systems. I, Regular papers》2008,55(3):851-860
In multicarrier systems, when the order of a channel impulse response is larger than the length of the cyclic prefix (CP), there is a significant performance degradation due to interblock interference (IBI). This paper proposes a blind-channel shortening method in which the equalizer parameter vector is formed by the noise subspace of the received signal correlation matrix so that the output power is maximized. The proposed method can not only shorten the effective channel impulse response to within the CP length but also maximize the output signal-to-interference-and-noise ratio while eliminating the IBI. We point out that the performance depends on the choice of a decision delay and propose a simple method for determining the appropriate delay. We propose both a batch algorithm and an adaptive algorithm and show by simulation that they are superior to the conventional algorithms. 相似文献
4.
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
5.
Kobayashi K. Kameyama M. Higuchi T. 《Industrial Electronics, IEEE Transactions on》1997,44(3):418-426
A new token-passing mechanism, priority token passing, which features real-time access and fast detection and recovery of transmission errors, is discussed in detail in comparison with standard token-passing protocols, and its large-scale integration (LSI)-oriented design concept is described. Priority token passing includes only a small performance overhead, due to its switching functions, which can change network topology from ring to broadcast medium. A token-holding node passes the token to another node after determining the successor through priority comparison. Errors occurring during token passing can, thus, be detected and corrected simply and promptly. Priority token passing has a simple hardware implementation, requiring only small additions to the frame control circuitry, and has a small implementation overhead. The priority token-passing protocol and two other important network communication functions, dual ring network reconfiguration and high-level data link control (HDLC) normal response mode-based message transmission, are designed as a single finite-state machine, and implemented into a compact LSI chip. This integrated instrument network (IINET) chip provides complete network communication services and requires only three additional external electronic components for operation 相似文献
6.
H Tsuga K Kameyama T Haga H Kurose T Nagao 《Canadian Metallurgical Quarterly》1994,269(51):32522-32527
Sequestration of m2 receptors (muscarinic acetylcholine receptor m2 subtypes), which was assessed as loss of N-[3H]methylscopolamine ([3H]NMS) binding activity from the cell surface, was examined in COS 7 and BHK-21 cells that had been transfected with expression vectors encoding the m2 receptor and, independently, vectors encoding a G protein-coupled receptor kinase (GRK2) (beta-adrenergic receptor kinase 1) or a GRK2 dominant-negative mutant (DN-GRK2). The sequestration of m2 receptors became apparent when the cells were treated with 10(-5) M or higher concentrations of carbamylcholine. In this case, approximately 40% or 20-25% of the [3H]NMS binding sites on COS 7 or BHK-21 cells, respectively, were sequestered with a half-life of 15-25 min. In cells in which GRK2 was also expressed, the sequestration became apparent in the presence of 10(-7) M carbamylcholine. Approximately 40% of the [3H]NMS binding sites on both COS 7 and BHK-21 cells were sequestered in the presence of 10(-6) M or higher concentrations of carbamylcholine. When DN-GRK2 was expressed in COS 7 cells, the proportion of [3H]NMS binding sites sequestered in the presence of 10(-5) M or higher concentrations of carbamylcholine was reduced to 20-30%. These results indicate that the phosphorylation of m2 receptors by GRK2 facilitates their sequestration. These results are in contrast with the absence of a correlation between sequestration and the phosphorylation of beta-adrenergic receptors by the GRK2 and suggests that the consequences of phosphorylation by GRK2 are different for different receptors. 相似文献
7.
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
8.
The extended Aharonov-Bohm period test, recently proposed by the present authors, is used to study the electron pairing transition in the t-J ladders. The critical point is detected as a gap opening in the extended spectral flow. The result suggests a pairing prior to the onset of a phase separation, which is consistent with a recent Tomonaga-Luttinger analysis. 相似文献
9.
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
10.
Y Shioda S Koizumi S Furuya S Akira N Kameyama N Hamano W Takahashi A Tokunaga N Tanaka M Onda 《Canadian Metallurgical Quarterly》1993,23(6):556-561
Respiratory infections are the most common infection in children. They differ remarkably according to age, bacteria and viruses. Therefore a careful history of outbreak, age, former infections, involvement of surroundings, symptoms, etc are essential. The present study included 50 children, aged between 0.3 and 12 yrs, all treated ambulatorily. 21 received brodimoprim (B) and 29 erythromycin (E). Indications were: tonsillitis, bronchitis, otitis media, sinusitis and scarlet fever. Dosages were: B was given 10 mg/kg body weight (b.w.) initially followed by 5 mg/kg b.w., once-a-day. The duration of treatment varied between 4 and 14 days (mean 8.3 days). E was given 30.50 mg/kg b.w. 3 times per day; duration 4 to 14 days (mean 8.6 days). Overall results were: in group B:12 cures, 5 improvements, 3 failures; 1 not assessable. In group E: 20 cures, 8 improvements, 1 failure. Side effects: in group B: vomiting (1), skin reaction (2), discontinuation (2); in group E: skin reaction (1), diarrhea (5), diarrhea+vomiting (1); discontinuation (2). The differences in efficacy and tolerability in the two groups are not statistically significant. The improved compliance with a single versus t.i.d. dosages has to be taken into account. 相似文献