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排序方式: 共有722条查询结果,搜索用时 312 毫秒
1.
A stochastic realization problem of a stationary stochastic process is re-visited, and a new stochastically balanced realization algorithm is derived in a Hilbert space generated by second-order stationary processes. The present algorithm computes a stochastically balanced realization by means of the singular value decomposition of a weighted block Hankel matrix derived by a “block LQ decomposition”. Extension to a stochastic subspace identification method explains how the proposed abstract algorithm is implemented in system identification. 相似文献
2.
T. Takeuchi T. Sasaki M. Hayashi K. Hamamoto K. Makita K. Taguchi K. Komatsu 《Photonics Technology Letters, IEEE》1996,8(3):361-363
A transceiver PIC consisting of a DFB-LD, a receiver PD and a Y-shaped branch waveguides is realized by in-plane bandgap energy controlled selective MOVPE. Both active and passive core layers are formed in one step selective growth, and complicated fabrication procedure is no longer required. More than 1 mW fiber coupled power and 7 GHz receiver bandwidth are obtained. The modulation and detection operations at 500 Mb/s are successfully demonstrated. 相似文献
3.
R Bucala Z Makita T Koschinsky A Cerami H Vlassara 《Canadian Metallurgical Quarterly》1993,90(14):6434-6438
To address potential mechanisms for oxidative modification of lipids in vivo, we investigated the possibility that phospholipids react directly with glucose to form advanced glycosylation end products (AGEs) that then initiate lipid oxidation. Phospholipid-linked AGEs formed readily in vitro, mimicking the absorbance, fluorescence, and immunochemical properties of AGEs that result from advanced glycosylation of proteins. Oxidation of unsaturated fatty acid residues, as assessed by reactive aldehyde formation, occurred at a rate that paralleled the rate of lipid advanced glycosylation. Aminoguanidine, an agent that prevents protein advanced glycosylation, inhibited both lipid advanced glycosylation and oxidative modification. Incubation of low density lipoprotein (LDL) with glucose produced AGE moieties that were attached to both the lipid and the apoprotein components. Oxidized LDL formed concomitantly with AGE-modified LDL. Of significance, AGE ELISA analysis of LDL specimens isolated from diabetic individuals revealed increased levels of both apoprotein- and lipid-linked AGEs when compared to specimens obtained from normal, nondiabetic controls. Circulating levels of oxidized LDL were elevated in diabetic patients and correlated significantly with lipid AGE levels. These data support the concept that AGE oxidation plays an important and perhaps primary role in initiating lipid oxidation in vivo. 相似文献
4.
En-Hai Sun Yong-Ho Choa Tohru Sekino Tomohiko Adachi Koichi Niihara 《Materials Research Innovations》2002,6(3):105-111
Cordierite/ZrO2 composites with 5 to 25 wt% ZrO2 were fabricated by conventional powder mixing and pressureless sintering method. Their densification behavior, microstructure,
mechanical and thermal properties were studied. By dispersing 25 wt% (9.57 vol%) ZrO2, densified cordierite/ZrO2 composite with a relative density of 98.5% was obtained at an optimum sintering condition of 1440 °C and 2 h. ZrO2 particles were homogenously dispersed within matrix grains and at the grain boundaries. The intragranular particles were
finer than 100 nm and the intergranular particles were coarser. Both fracture strength and toughness could be enhanced more
than two times higher, compare to those of monolithic cordierite, by dispersing 25 wt% ZrO2 into the cordierite matrix. The toughening mechanism in the present composites was mainly attributed to martensitic transformation
due to ZrO2 dispersion.
Electronic Publication 相似文献
5.
Tohru Morii Hiroyuki Hamada Muriel Desaeger Akihiko Gotoh Atsushi Yokoyama Ignaas Verpoest Zen-ichiro Maekawa 《Composite Structures》1995,32(1-4):133-139
This study deals with the impact property and damage tolerance of matrix hybrid composite laminates with different laminate constitution. The matrix hybrid composite laminates consisted of the laminae with a conventional epoxy resin and the laminae with a flexible epoxy resin modified from the conventional resin to avoid the interlaminar delamination. The impact energy absorption ratio greatly depended on the matrix resin placed at the impact face. The energy absorption was almost constant if the conventional resin was placed at the impact surface layer, while it increased exponentially with the increasing fraction of the flexible resin if the flexible resin was placed at the impact face. The impact energy was absorbed by the damage development and propagation in the laminate with conventional resin laminae as the impacted face, while it was absorbed by both the recoverable deformation of the flexible resin and the damage propagation in the laminate with flexible resin laminae as the impacted face. 相似文献
6.
Y Nakamura Y Horii T Nishino H Shiiki Y Sakaguchi T Kagoshima K Dohi Z Makita H Vlassara R Bucala 《Canadian Metallurgical Quarterly》1993,143(6):1649-1656
Advanced glycosylation end products (AGEs) accumulate on long-lived extracellular matrix proteins and have been implicated in the micro- and macrovascular complications of diabetes mellitus. Within the arterial wall, AGE-modified proteins increase vascular permeability, inactivate nitric oxide activity, and induce the release of growth-promoting cytokines. Recently developed anti-AGE antibodies were used in an immunohistochemical analysis of coronary arteries obtained from type II diabetic and nondiabetic patients. High levels of AGE reactivity were observed within the atherosclerotic plaque present in vessels from selected patients with diabetes. Considered together with the pathological effects of AGEs on vascular wall homeostasis, these data support the role of advanced glycosylation in the rapidly progressive atherosclerosis associated with diabetes mellitus. 相似文献
7.
Yasuyuki Itoh Tohru Sugawara 《Journal of Infrared, Millimeter and Terahertz Waves》1996,17(2):465-475
This paper describes a quasi-optical method for the conversion of modes transmitted through highly oversized circular waveguides. A waveguide-mode is radiated once from a waveguide cut in the form of a radiation beam, which is then properly shaped by two curved mirrors and directed back into the waveguide. The curved mirror shapes are iteratively and automatically determined for given propagation distances using the design technique for phase correction mirrors. The proposed method gives favorable results in designing a waveguide expander/reducer, a TE01-TE02 mode converter, and a TE01-HE11 mode converter. 相似文献
8.
In this article, a new control scheme named repetitive control is proposed for a class of nonlinear systems described by x(t) = Ax(t) + Bu(t) + n(x(t)) and y(t) = Cx(t), in which the controlled variables follow periodic reference commands. The stability condition is derived by applying the passivity theorem. We show how to apply the repetitive control scheme to the trajectory control of a manipulator. A simple repetitive control scheme is developed for the trajectory control of a manipulator by using nonlinear compensation and feedbacks of position and velocity signals. Experimental results for a three link manipulator verify that the proposed repetitive control reduces the tracking error to a very low level. 相似文献
9.
Constant stress creep under compression stress, 100 to 316 MPa, at 1100 K was investigated on single-phase TiAl intermetallics. The material was ingot-cast, isothermally forged, and then annealed to produce stable equi-axed grain structures, whose average grain diameters were 25, 42 and 70m. Creep curves were very similar among the three specimens with different grain diameters and the creep rates at a given strain, as well as the minimum creep rates, depended little on grain size. Two regimes were observed on the stress dependence of the minimum creep rate. The stress exponent under high stresses was about 4.5, independent of grain size. Under stresses lower than about 150 MPa it became about 8. 相似文献
10.
Solid-liquid phase equilibria of the benzene + 2-methyl-2-propanol system have been investigated at temperatures from 278 to 323 K and pressures up to 300 MPa using a high-pressure optical vessel. The uncertainties of the measurements of temperature, pressure and composition are within ±0.1 K, ±0.5 MPa, and ±0.001 mole fraction, respectively. The freezing pressure at a constant composition increases monotonously with pressure. The eutectic point shifts to a higher temperature and benzene-rich composition with increasing pressure. In order to describe the pressure-temperature-composition relation of high-pressure solid-liquid phase equilibria, a new simple equation has been proposed as follows:
相似文献 |