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顶矿微元素-72对艾迪(AD)肉用童子鸡的促生长作用
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作者 隋星月 李睿义 《天津农业科学》 CAS 1998年第A00期46-48,共3页
添加1%或2%的顶矿微元素可明显提高艾迪肉用童子鸡的增重作用并降低死亡率。经与对照组对比分析,在一个饲养期每只鸡可提高经济效益分别为1.1元和1.44元,经济效益十分明显。
关键词 矿微元素72 肉鸡 增重性能
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基于内涵亏值的概念格渐进式构建 被引量:4
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作者 吴杰 梁妍 马垣 《计算机应用》 CSCD 北大核心 2017年第1期222-227,共6页
为了避免构建概念格时的繁琐过程,提高概念格构建的效率,提出了一种基于内涵亏值通过查找顶元素来快速渐进式生成概念格的新方法。首先,形式化地定义了顶元素、旧概念、产生概念、新概念、产生子概念、内涵亏值集合、剩留父概念、超集... 为了避免构建概念格时的繁琐过程,提高概念格构建的效率,提出了一种基于内涵亏值通过查找顶元素来快速渐进式生成概念格的新方法。首先,形式化地定义了顶元素、旧概念、产生概念、新概念、产生子概念、内涵亏值集合、剩留父概念、超集删除与正则队列;提出了概念格元素是否为顶元素的判定定理并给出了其证明;其次,在原概念格的正则队列中依次取概念元素,经超集删除后得到剩留父概念;最后,从剩留父概念查找其所在等价类的顶元素,逐步生成新概念格的正则队列。理论分析时间复杂度较基于属性的渐进式概念格生成(CLIF_A)算法与FastAddIntent算法有效降低,在实验例证对比中,概念数目大于150时,所用时间远少于对比算法。实验结果表明该算法方法简单,构建效率较对比算法明显提高。 展开更多
关键词 概念格 内涵亏值 顶元素 超集删除 正则队列
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Effect of trace elements on growth of Pinus tabulaeformis seedling 被引量:7
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作者 刘晓东 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第4期285-288,337,共4页
The stimulative effect of trace elements on seed germination and seedling growth of Pinus tabulaeformis was tested. The experiments were carried out on seed soak and topdressing with different trace elements and varie... The stimulative effect of trace elements on seed germination and seedling growth of Pinus tabulaeformis was tested. The experiments were carried out on seed soak and topdressing with different trace elements and varied concentrations at the nursery of Gardens Research Institute, Harbin, in 2000-2001. The experimental results showed that soaking seed with 1% and 0.2% concentrations of Mn element produced best result for seed germination, and the germination rate was increased by 9%~19% for the seeds treated with 1% concentration and 12%~14% for the seeds treated with 0.2% concentration compared with the control group. The seeds treated with boron element had lowest germination rate. For trace element topdressing, Mn and Mo elements presented good result for seedling growth and the treatment with low concentration was even better. The height or chlorophyll content of the seedlings with spray of low-concentration Mn and Mo element was much higher than that of untreated ones. In the contrast to the treating method of seed soak, topdressing (application of spraying on foliage) had evident effect on seedling growth. 展开更多
关键词 Pinus tabulaeformis Trace element Seed soaking TOPDRESSING Seed germination Seedling growth
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堆栈技术及其应用
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作者 李大友 《中国远程教育》 1985年第4期40-42,共3页
近年来,在大多数微型计算机中都采用了堆栈技术。这是因为,采用堆栈技术可以进一步提高计算机系统的工作效率。堆栈技术在实现主程序与子程序之间的链接和信息交换、实现现行程序与中断服务程序之间的链接以及实现算术表达式求值等很多... 近年来,在大多数微型计算机中都采用了堆栈技术。这是因为,采用堆栈技术可以进一步提高计算机系统的工作效率。堆栈技术在实现主程序与子程序之间的链接和信息交换、实现现行程序与中断服务程序之间的链接以及实现算术表达式求值等很多方面,均是极为有用的技术。本文主要介绍以下几个问题。一、堆栈的概念和定义堆栈是一种特殊的数据结构。所谓数据,就是描述客观事物的数、字符以及所有能输入到计算机中,并能被计算机程序处理的符号的集合。数据的基本单位是数据元素。 展开更多
关键词 堆栈操作 栈底 数据元素 顶元素 字符串长度 堆栈指示器 寄存器对 GE算法 主程序与子程序 PUSH
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Parameter vertex method and its parallel solution for evaluating the dynamic response bounds of structures with interval parameters 被引量:4
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作者 ZhiPing Qiu PengBo Wang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2018年第6期62-74,共13页
In this article, we propose a parameter vertex method to determine the upper and lower bounds of the dynamic response of structures with interval parameters, which can be regarded as an extension of the matrix vertex ... In this article, we propose a parameter vertex method to determine the upper and lower bounds of the dynamic response of structures with interval parameters, which can be regarded as an extension of the matrix vertex method proposed by Qiu and Wang. The matrix vertex method requires considerable computation time and encounters the dependency problem in practice,thereby limiting its application in engineering. The proposed parameter vertex method can avoid the dependency problem, and the number of possible vertex combinations in the proposed method is significantly less than that in the matrix vertex method.The parameter vertex method requires that each matrix element in the dynamic differential equation is monotonic with respect to the uncertain parameter, and that the dynamic response reaches its extreme value when the uncertain parameter is at its endpoint.To further reduce the runtime, both vertical and transversal parallel algorithms are introduced and integrated into the parameter vertex method to improve its computational efficiency. Two numerical examples are presented to demonstrate the proposed method combined with both parallel algorithms. The performances of the two parallel algorithms are thoroughly studied. The parameter vertex method combined with parallel algorithm can be used for large-scale computing. 展开更多
关键词 parameter vertex method dynamic response interval parameter parallel algorithm upper and lower bounds
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Transformation Method of Exterior Orientation Angular Elements Obtained via Position and Orientation System Under Gauss-Kruger Projection Coordinate System
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作者 YUAN Xiuxiao ZHANG Xueping FU Jianhong 《Geo-Spatial Information Science》 2010年第3期157-165,共9页
Data obtained via airborne position and orientation system (POS) is in WGS 84 global geocentric reference frame, while the national coordinate reference system for topographic mapping in China is generally Gauss-Kru... Data obtained via airborne position and orientation system (POS) is in WGS 84 global geocentric reference frame, while the national coordinate reference system for topographic mapping in China is generally Gauss-Kruger projection coordinate system. Therefore, data obtained via a POS must be transformed to national coordinate system. Owing to the effects of earth curvature and me- ridian deviation, there are some errors in the process of angle transformation from roll, pitch, and heading (φ,θ,ψ) obtained directly via a POS to the attitude angles of images (φ,ω,κ) needed in photogrammetry. On the basis of effect theories of earth curvature and meridian deviation on exterior orientation angular elements of images, a method using a compensation matrix to correct the transformation errors from attitude angles obtained via the POS to exterior orientation angular elements of images is proposed in this paper. Moreover, the rigorous formula of the compensation matrix is deduced. Two sets of actual data obtained via a POS AV 510, which are different in scale and terrain, are selected and used to perform experiments. The empirical results not only indicate that the compensation matrix proposed in this paper is correct and practical but also show that transformation accuracy of exterior orientation angular elements obtained via the POS based on compensation matrix is relevant to the selection of vertical axis (a projection of central meridian) of Gauss-Kruger projection coordinate system; the proper vertical axis should be the Gauss-Kruger projection of the central meridian of projection zone in which the survey area locates. However, the transformation accuracy of exterior orientation angular elements is irrelevant to the choice of origin of coordinate system; it is appropriate that the origin of coordinate system locates at the center point of the survey area. Moreover, transformation accuracy of exterior orientation angular elements achieved based on the compensa- tion matrix deduced in this paper is higher than that obtained via the existing POS processing software. 展开更多
关键词 position and orientation system (POS) exterior orientation elements of image earth curvature meridian deviation compensation matrix
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