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181.
ISD单片语音录/放器件及电路设计 总被引:1,自引:0,他引:1
ISD单片语音器件的独特之处,是有用直接模拟存储技术,语音信号以其原本的模拟形式直接存入模拟量存储器中并长远保存。省去了传统的A/D和D/A数模转换机制,能高保真的将语音内容再生。这是一种高新录/放技术。另外,给出的ISD基本录/放电路十分简单易用。可方便地为微机系统、测控仪表、电器和广播等设备所采用,使设备具有高效功能。 相似文献
182.
Despite the availability of 3D CAD systems, the designers in shipyards still use 2D CAD systems because of the need to produce drawings rapidly and a shortage of labor. The shipyard spends much time and labor analyzing the design information contained in 2D drawings and creating 3D model for the downstream processes. The design information is represented by symbols that are well known among designers in shipyard. Symbols are expressed by meaningless geometric shapes. These shapes are recognized to have meanings by analysis of experienced and knowledgeable designers.We propose a method for automatic recognition of 2D symbols and the extraction of design information from the midship drawings. The shape and rationale of 2D symbols used in ship design have been analyzed, and symbols have been classified according to the analysis. Based on the classified symbols, the developed system recognizes the symbols expressed in 2D drawings. The extracted design information is assorted by design rationales. The meaningless geometric shape is translated into the design information including designer's intents. The extracted design data can be applied to the design process in shipyards, and the 3D ship model can be automatically created. 相似文献
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185.
根据福建元洪港无长期海浪和风观测资料及该水域的多岛礁地形的特征,以邻近的平潭海洋站30a实测海浪资料,采用考虑底摩擦效应的浅水波浪折射数值模式进行港区设计波高计算,并与港工程规范算法相比较,得出码头,航道口门和航道中段的设计波高参数。 相似文献
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188.
根据导线近似平差原理,以Visual FoxPro 6.0为开发平台,设计导线平差程序.该程序可完成闭合导线的平面控制和高程控制平差,并能将平差结果根据不同需要生成多种格式文件导出,同时还能绘制导线图. 相似文献
189.
A study of methods to estimate debris flow velocity 总被引:8,自引:2,他引:6
Debris flow velocities are commonly back-calculated from superelevation events which require subjective estimates of radii
of curvature of bends in the debris flow channel or predicted using flow equations that require the selection of appropriate
rheological models and material property inputs. This research investigated difficulties associated with the use of these
conventional velocity estimation methods. Radii of curvature estimates were found to vary with the extent of the channel investigated
and with the scale of the media used, and back-calculated velocities varied among different investigated locations along a
channel. Distinct populations of Bingham properties were found to exist between those measured by laboratory tests and those
back-calculated from field data; thus, laboratory-obtained values would not be representative of field-scale debris flow behavior.
To avoid these difficulties with conventional methods, a new preliminary velocity estimation method is presented that statistically
relates flow velocity to the channel slope and the flow depth. This method presents ranges of reasonable velocity predictions
based on 30 previously measured velocities. 相似文献
190.
On February 6, 1994, a large debris flow developed because of intense rains in a 800-m-high mountain range called Serra do Cubatão, the local name for the Serra do Mar, located along the coast of the state of São Paulo, Brazil. It affected the Presidente Bernardes Refinery, owned by Petrobrás, in Cubatão. The damages amounted to about US $40 million because of the muck cleaning, repairs, and 3-week interruption of the operations. This prompted Petrobrás to conduct studies, carried out by the authors, to develop protection works, which were done at a cost of approximately US $12 million. The paper describes the studies conducted on debris flow mechanics. A new criteria to define rainfall intensities that trigger debris flows is presented, as well as a correlation of slipped area with soil porosity and rain intensity. Also presented are (a) an actual grain size distribution of a deposited material, determined by laboratory and a large-scale field test, and (b) the size distribution of large boulders along the river bed. Based on theory, empirical experience and back-analysis of the events, the main parameters as the front velocity, the peak discharge and the volume of the transported sediments were determined in a rational basis for the design of the protection works. Finally, the paper describes the set of the protection works built, emphasizing their concept and function. They also included some low-cost innovative works. 相似文献