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排序方式: 共有718条查询结果,搜索用时 15 毫秒
91.
This article outlines the development of a digital three-term industrial controller from the initial marketing requirement to the final product. The major functions of the instrument are performed by a 3872 masked microprocessor. An EAROM is used to provide nonvolatile storage for operator-entered parameters and to store instrument characterisation data. A 6809 based programming/calibration station and a portable programmer for in-field programming are also described. 相似文献
92.
Ashley J.J. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1988,34(3):389-399
The author gives an upper bound on the necessary length of a sliding-block decoder window for finite-state codes from arbitrary n -ary data into any constrained system Σ with capacity at least log(n ) presented by a graph G with memory m and anticipation a . Specifically, it is shown that the ACH code construction algorithm can be used to construct a code with a sliding-block decoder at rate t :t and with window length m +a +2t , where t is upper-bounded by a linear function of the number of states of G. It is demonstrated that this is the best one can do in the sense that any general upper bound on the decoder window length for finite-state codes into systems Σ with finite memory must grow at least linearly with the number of states of the graph G presenting Σ 相似文献
93.
94.
Boyer AE Moura H Woolfitt AR Kalb SR McWilliams LG Pavlopoulos A Schmidt JG Ashley DL Barr JR 《Analytical chemistry》2005,77(13):3916-3924
We have developed an assay (Endopep-MS) that detects the specific endoproteinase activities of all seven BoNT types by mass spectrometry (MS). Each BoNT type cleaves a unique site on proteins involved in neuronal transmission. Target peptide substrates based on these proteins identify a BoNT type by its enzymatic action on the substrate and the production of two peptide products, which are then detected by matrix-assisted laser desorption/ionization time-of-flight MS or liquid chromatography electrospray ionization MS/MS. We showed the ability to detect all seven toxin types in a multiplexed assay format. The detection limits achieved range from 0.039 to 0.625 mouse LD(50)/mL for toxin types A, B, E, and F in a buffer system. The Endopep-MS assay is the first to differentiate all seven BoNT types, is sensitive, specific, and has the potential to quantify toxin activity. 相似文献
95.
Significance of Blood Flow in Calculations of Temperature in Laser Irradiated Tissue 总被引:1,自引:0,他引:1
Welch Ashley J. Wissler E. H. Priebe Leslie A. 《IEEE transactions on bio-medical engineering》1980,(3):164-166
A dimensionless solution of the heat conduction equation for laser irradiation of tissue has been extended to include transport of heat owing to blood flow. The importance of the heat loss term is discussed in relation to the perfusion rate and exposure duration. 相似文献
96.
Quantitative analysis of food structure is commonly obtained by image analysis of a small portion of the material that may not be the representative of the whole sample. In order to quantify structural parameters (air cells) of 2 types of bread (bread and bagel) the concept of representative volume element (RVE) was employed. The RVE for bread, bagel, and gelatin-gel (used as control) was obtained from the relationship between sample size and the coefficient of variation, calculated from the apparent Young's modulus measured on 25 replicates. The RVE was obtained when the coefficient of variation for different sample sizes converged to a constant value. In the 2 types of bread tested, the tendency of the coefficient of variation was to decrease as the sample size increased, while in the homogeneous gelatin-gel, it remained always constant around 2.3% to 2.4%. The RVE resulted to be cubes with sides of 45 mm for bread, 20 mm for bagels, and 10 mm for gelatin-gel (smallest sample tested). The quantitative image analysis as well as visual observation demonstrated that bread presented the largest dispersion of air-cell sizes. Moreover, both the ratio of maximum air-cell area/image area and maximum air-cell height/image height were greater for bread (values of 0.05 and 0.30, respectively) than for bagels (0.03 and 0.20, respectively). Therefore, the size and the size variation of air cells present in the structure determined the size of the RVE. It was concluded that RVE is highly dependent on the heterogeneity of the structure of the types of baked products. 相似文献
97.
Steven J Adamson Dan Ashley William Hassler Jared Wilburn XQ Gao 《电子工业专用设备》2009,38(7):21-24,41
微电子组装的大部份工艺开发都要求将元件做到更小,以便在尺寸日益缩小的便携式设备上实现更多功能。阐述了大元件的底部填充,即一侧的尺寸超过15mm,底部填充的胶量介于30~50mg。大尺寸晶元的制造工艺要求比现有生产线更大的产能,这就给底部填充点胶带来更大的挑战。大元件的产能超过3000个/h时,需要点胶机点出非常多的胶水。如此多的胶水在出胶前通过点胶阀,这将会带来加热的问题-某些工艺要求出胶前胶水必须要加热。这会对胶点尺寸有影响,因为随着温度的变化,底部填充的胶水黏度也会随之变化,从而轻微影响点出的胶量。从而将影响晶元相邻的“非沾染区”。稳定的温度是点胶稳定性的保证,并且能帮助胶水流进晶元下方同时也有助胶水分离从而更容易喷射出来。从研究中可以观察到:系统温度环境(点胶机内部)对点胶的胶水质量有影响。 相似文献
98.
Sanghadasa M. Ashley P.R. Lindsay G.A. Bramson M.D. Tawney J. 《Lightwave Technology, Journal of》2009,27(6):806-813
Precision guidance in navigation systems requires highly accurate, compact, and low cost inertial measurement units (IMUs). The key active guided-wave component of the IMU is the phase modulator. In our approach, electro-optic polymers have been utilized in fabricating low loss phase modulators with low half-wave drive voltage using advanced hybrid waveguide fabrication processes and novel optical integration techniques. However, the interference between the primary wave and the backscatter waves generated by the phase modulator and/or the interference between the two counter-propagating backscatter waves at the detector of the IMU has been a major source of error in this approach. A novel technique was introduced in assessing the error caused by backscatter and an offset waveguide design was developed to suppress the interference of backscatter light. The novel design not only preserved the miniaturization, but also improved the insertion loss with the use of a shorter waveguide. The gyro level tests performed with the backscatter compensated modulators showed about 5 times improvement of the average bias uncertainty over gyros integrated with a standard symmetric phase modulator. 相似文献
99.
Akter Nusnin Sadowski Jerzy T. Zhou Chen Zhong Jian-Qiang van Spronsen Matthijs Xu Yixin Tong Xiao Kim Taejin Tenney Samuel Head Ashley R. Stacchiola Dario J. Boscoboinik J. Anibal 《Topics in Catalysis》2019,62(12-16):1067-1075
Topics in Catalysis - The morphology of a thin palladium film deposited on bilayer Al0.35Si0.65O2/Ru(0001), previously proposed as a two-dimensional zeolite model, is investigated using a set of... 相似文献
100.