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排序方式: 共有4517条查询结果,搜索用时 12 毫秒
21.
A combination of soy flour and isolated soy protein was investigated as the adhesive in pigmented paper coatings that contained dialdehyde starch (DA) as the insolubilizing agent. A coating formula of 50% solids made up of 8.3 parts soy flour, 8 parts isolated soy protein and 0.5 part DAS per 100 parts of clay exhibited pseudoplastic and thixotropic flow properties characteristic of coating colors containing more costly protein adhesives. Both was pick and wet-rub resistance of the paper coating were improved and putrefaction retarded by the use of DAS in the formulation. Brightness, was pick and wet-rub resistance values compared favorably with those of a reference coating containing 12.5 parts of isolated soy protein and 0.5 parts DAS per 100 parts of clay. 相似文献
22.
Human hands sweat in different circumstances and the presence of sweat can alter the friction between the hand and contacting surface. It is, therefore, important to understand how hand moisture varies between people, during different activities and the effect of this on friction. In this study, a survey of fingertip moisture was done. Friction tests were then carried out to investigate the effect of moisture. Moisture was added to the surface of the finger, the finger was soaked in water, and water was added to the counter-surface; the friction of the contact was then measured. It was found that the friction increased, up until a certain level of moisture and then decreased. The increase in friction has previously been explained by viscous shearing, water absorption and capillary adhesion. The results from the experiments enabled the mechanisms to be investigated analytically. This study found that water absorption is the principle mechanism responsible for the increase in friction, followed by capillary adhesion, although it was not conclusively proved that this contributes significantly. Both these mechanisms increase friction by increasing the area of contact and therefore adhesion. Viscous shearing in the liquid bridges has negligible effect. There are, however, many limitations in the modelling that need further exploration. 相似文献
23.
N. Carr J. Thompson G. G. Jones I. Griffith A. J. Moseley P. M. Charles 《Journal of Electronic Materials》1995,24(11):1617-1620
The use of optoelectronic integrated circuits (OEICs) is now emerging as a practical technology for a variety of applications, particularly in advanced telecommunications. OEICs consist of a range of devices such as lasers, waveguides, modulators, amplifiers, transistors, detectors, etc. fabricated on the same substrate. When a semi-insulating substrate is used, these devices can be electrically isolated by channel etching, resulting in a low capacitance structure with reduced electrical interference between the subcomponents. One of the devices which is particularly advantageous for this type of integration scheme is the distributed feedback (DFB) laser. The laser can be made to function more efficiently by minimizing the current flowing outside the active region. This can be achieved by surrounding the active region with semi-insulating iron doped InP. This work describes for the first time, the MOVPE growth, fabrication, and device characterization of 1.3 um buried heterostructure DFB MQW lasers, which combine the advantages of using both a semi-insulating substrate and a semi-insulating infill region in the same device structure. The potential advantage of this design scheme is improved OEIC performance as a result of, reduced capacitance and electrical crosstalk, enhanced laser output power, higher speed, increased efficiency, wider operating temperature and reduced threshold current. The laser active region consists of 8 x 140 Å quantum wells of GalnAsP (λ = 1.3 μm) and 110 Åbarriers of GalnAsP (λ= 1.07 μm). Single mode 1.3 urn devices of length 250 μm operating at room temperature produced threshold currents of 8 mA, efficiencies of up to 25%, output powers of 18 mW at 80 mA (pulsed), and a frequency response greater than 12GHz. The parasitic capacitance was estimated to be less than 3 pF. 相似文献
24.
Dave Carr Audrey Mendoza 《电子产品世界》2005,(17):88-89
用户对激动人心的全新网络服务的需求,正在推动网络带宽和数据流量的增长.作为回应,网络正在向更有效的以包为基础的模式发展,这种模式使网络能够为用户提供其需要的服务,并开发出额外的收入来源.网络设备制造商必须掌握包处理技术,才能提供新的服务,从而应对不断增加的网络复杂性及适应不同网速的要求. 相似文献
25.
Williams P.J. Walker R.G. Charles P.M. Ogden R. Wood A.K. Carr N. Carter A.C. 《Electronics letters》1991,27(10):809-810
The fabrication and characterisation of monolithically integrated OEIC transceivers for use in optical subscriber access links are reported. A design incorporating DFB lasers, wavelength duplexers and a monitor photodiode, specific to the TPON/BPON passive optical network configuration is presented.<> 相似文献
26.
Usner B.C. Sertel K. Carr M.A. Volakis J.L. 《Antennas and Propagation, IEEE Transactions on》2006,54(1):68-75
Numerical solutions of volume integral equations with high contrast inhomogeneous materials require extremely fine discretization rates making their utility very limited. Given the application of such materials for antennas and metamaterials, it is extremely important to explore computationally efficient modeling methods. In this paper, we propose a novel volume integral equation technique where the domain is divided into different material regions each represented by a corresponding uniform background medium coupled with a variation, together representing the overall inhomogeneity. This perturbational approach enables us to use different Green's functions for each material region. Hence, the resulting volume-surface integral equation alleviates the necessity for higher discretizations within the higher contrast regions. With the incorporation of a junction resolution algorithm for the surface integral equations defined on domain boundaries, we show that the proposed volume-surface integral equation formulation can be generalized to model arbitrary composite structures incorporating conducting bodies as well as highly inhomogeneous material regions. 相似文献
27.
Joo Leong Tham Margarit M.A. Pregardier B. Hull C.D. Magoon R. Carr F. 《Solid-State Circuits, IEEE Journal of》1999,34(3):286-291
A 2.7-V 900-MHz/1.9-GHz dual-band transceiver IC consisting of receive, transmit, and local oscillator (LO) sections is presented. The transmit section achieves an unwanted sideband suppression of -43 dBc, LO leakage of -59 dBc, and third-order spurious rejection of -70 dBc. The transmit output noise level is -165 dBc/Hz at a 20-MHz offset from the carrier. The on-chip very high-frequency oscillator has a phase-noise level of -106 dBc/Hz at 100-kHz offset when operating at 800 MHz. The receive section has 36 dB of gain with 36 dB of gain range in 12-dB steps. The transceiver IC has been fabricated using a 25-GHz ft silicon bipolar process and is designed to operate over a supply-voltage range of 2.7-5.0 V 相似文献
28.
A model for residual life prediction based on Brownian motion with an adaptive drift 总被引:3,自引:0,他引:3
A degradation model is presented in this paper for the prediction of the residual life using an adapted Brownian motion-based approach with a drifting parameter. This model differs from other Brownian motion-based approaches in that the drifting parameter of the degradation process is adapted to the history of monitored information. This adaptation is performed by Kalman filtering. We also use a threshold distribution instead of the usual single threshold line which is sometime difficult to obtain in practice. We demonstrate the model using some examples and show that the model performs reasonably well and has a better prediction ability than the standard Brownian motion-based model. The model is then fitted to the data generated from a simulator using the expectation-maximization algorithm. We also fit a standard Brownian motion-based model to the same data to compare the difference and performance. The result shows that the adapted model performs better in terms of certain test statistics and the total mean square errors. 相似文献
29.
Benzocyclobutene (BCB) dielectrics for the fabrication of high density,thin film multichip modules 总被引:1,自引:0,他引:1
David Burdeaux Paul Townsend Joseph Carr Philip Garrou 《Journal of Electronic Materials》1990,19(12):1357-1366
A new class of organic dielectrics, benzocyclobutenes, 1, are described and their application to the fabrication of thin film
multichip modules is detailed. Key properties for3, a siloxy containing BCB derivative include low dielectric constant (2.7), low loss (0.008 at 1 MHz), low water absorption
(0.25% after 24 h water boil) and high degree of planarization (>90% from one layer coverage). All other properties meet the
requirements necessary for fabrication of thin film MCM structures. 相似文献
30.
David Helbert Philippe Carré Eric Andres 《IEEE transactions on image processing》2006,15(12):3701-3714
In this paper, we propose an implementation of the 3-D Ridgelet transform: the 3-D discrete analytical Ridgelet transform (3-D DART). This transform uses the Fourier strategy for the computation of the associated 3-D discrete Radon transform. The innovative step is the definition of a discrete 3-D transform with the discrete analytical geometry theory by the construction of 3-D discrete analytical lines in the Fourier domain. We propose two types of 3-D discrete lines: 3-D discrete radial lines going through the origin defined from their orthogonal projections and 3-D planes covered with 2-D discrete line segments. These discrete analytical lines have a parameter called arithmetical thickness, allowing us to define a 3-D DART adapted to a specific application. Indeed, the 3-D DART representation is not orthogonal, It is associated with a flexible redundancy factor. The 3-D DART has a very simple forward/inverse algorithm that provides an exact reconstruction without any iterative method. In order to illustrate the potentiality of this new discrete transform, we apply the 3-D DART and its extension to the Local-DART (with smooth windowing) to the denoising of 3-D image and color video. These experimental results show that the simple thresholding of the 3-D DART coefficients is efficient. 相似文献