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排序方式: 共有886条查询结果,搜索用时 15 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.
Toru Ikegami Hideyuki Negishi Dai Kitamoto Keiji Sakaki Tomohiro Imura Masayoshi Okamoto Yasushi Idemoto Nobuyuki Koura Tsuneji Sano Kenji Haraya Hiroshi Yanagishita 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(4):381-387
In order to produce highly concentrated bioethanol by pervaporation using an ethanol‐permselective silicalite membrane, techniques to suppress adsorption of succinic acid, which is a chief by‐product of ethanol fermentation and causes the deterioration in pervaporation performance, onto the silicalite crystals was investigated. The amount adsorbed increased as the pH of the aqueous succinic acid solution decreased. The pervaporation performance also decreased with decreasing pH when the ternary mixtures of ethanol/water/succinic acid were separated. Using silicalite membranes individually coated with two types of silicone rubber, pervaporation performance was significantly improved in the pH range of 5 to 7, when compared with that of non‐coated silicalite membranes in ternary mixtures of ethanol/water/succinic acid. Moreover, when using a silicalite membrane double‐coated with the two types of silicone rubber, pervaporation performance was stabilized at lower pH values. In the separation of bioethanol by pervaporation using the double‐coated silicalite membrane, removal of accumulated substances having an ultraviolet absorption maximum at approximately 260 nm from the fermentation broth proved to be vital for efficient pervaporation. Copyright © 2005 Society of Chemical Industry 相似文献
3.
Visakha K. Nanayakkara Yasuyuki Ikegami Haruo Uehara 《International Journal of Refrigeration》2002,25(6)
This paper presents a novel neural network (NN) to control an ammonia refrigerant evaporator. Inspired by the latest findings on the biological neuron, a dynamic synaptic unit (DSU) is proposed to enhance the information processing capacity of artificial neurons. Treating the dynamic synaptic activity after the nonlinear somatic activity helps to capture the dynamics demarcated by the Gaussian activation pertaining to the input space. This practice leads to a remarkable reduction in curse of dimensionality. The proposed NN architecture has been compared with two other conventional architectures; one with dynamic neural units (DNUs) and the other with nonlinear static functions as perceptrons. The objective is to control evaporator heat flow rate and secondary fluid outlet temperature while keeping the degree of refrigerant superheat in the range 4–7 K at the evaporator outlet by manipulating refrigerant and evaporator secondary fluid flow rates. The drawbacks of conventional approaches to this problem are discussed, and how the novel method can overcome them are presented. An evolutionary approach is adopted to optimize the parameters of the NN controllers. Then evaporator process model is accomplished as a combination of governing equations and a sub NN resulting in a simple and sufficiently accurate model. The effectiveness of the proposed dynamic NN controller for the evaporator system model is validated using experimental data from the ammonia refrigeration plant. 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.
K. Matsumoto T. Ikegami S. Ito M. Kirigaya Y. Okuda 《Journal of Low Temperature Physics》1996,102(1-2):227-235
A precise velocity measurement of zero and first sound in normal3He was performed over the pressure range of 0.5 bar and 10 bar at a frequency of 389.1 MHz using a phase detection technique. From these measurements, the Fermi liquid parameter F
2
s
was determined as a function of pressure. The new value of F
2
s
was positive and less than 0.25 at all pressures below 10 bar. It allows propagation of transverse zero sound mode for all pressures within the current theoretical picture. 相似文献
6.
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
7.
8.
Takaaki Wajima Tomoe Shimizu Yasuyuki Ikegami 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(6):921-927
BACKGROUND: This study aimed to investigate the synthesis of zeolites from paper sludge ash (PSA) with added diatomite to remove both NH4+ and PO43? for water purification. The PSA had low Si and significant Ca contents. Four types of diatomite: white (T‐W) and brown (T‐B) from deposits of marine origin in Takanosu, and white (S‐W) and gray (S‐G) from lacustrine deposits in Shonai, were added to NaOH solution to increase the Si content and thereby synthesize zeolites with high cation exchange capacity (CEC). RESULTS: The order of the amounts of Si extracted from the diatomite to the alkali solution was S‐W > T‐W = T‐B > S‐G, which correlates with the amorphous SiO2 content of diatomite. The original ash without addition of diatomite yielded hydroxysodalite with CEC of about 1.0 mmol g?1. For all samples, the addition of diatomite to the solution yielded zeolite‐P with a higher CEC, but the addition of excess Si inhibited the synthesis of zeolite‐P, and the CEC of the product was low. A product with high CEC including zeolite‐P was obtained in a solution with around 500 mmol L?1 of Si concentration, and had the ability to remove both NH4+ and PO43?. CONCLUSION: Diatomite has the potential for used as an additive for the synthesis of high CEC zeolite from PSA. The product with zeolite‐P exhibited relatively high CEC, capacity for NH4+ uptake, and the ability to remove PO43? by precipitation, which is preferable for water purification applications. Copyright © 2008 Society of Chemical Industry 相似文献
9.
The photodegradation of seven carbamate pesticides (bendiocarb, isoprocarb, promecarb, ethiofencarb, furathiocarb, fenoxycarb and pirimicarb), in aqueous solution, has been examined by GC-MS. The most general result was formation of the corresponding phenols. Irradiation of isoprocarb and promecarb also resulted in photo-Fries rearrangement to ortho- and para-hydroxybenzamides. In the case of ethiofencarb photocleavage of the carbon-sulfur bond gave 2-methylphenyl methylcarbamate as main product. Likewise, N-S bond cleavage occurred upon irradiation of furathiocarb, to allow the formation of the carbamate insecticide carbofuran, butyl methylcarbamate and carbofuranphenol. Under similar conditions, fenoxycarb gave p-phenylphenol and 2-hydroxydibenzofuran, through primary homolysis of the aryloxy-methylene bond. Finally, pirimicarb gave rise to 2-formylamino-5,6-dimethylpyrimidin-4-yl dimethylcarbamate. 相似文献
10.
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