三硝基苯甲酸的合成

研究了从三硝基甲苯出发，经催化氧化制备三硝基苯甲酸的反应，找出了最佳的氧化条件，得到熔点范围２２７℃－２２９℃，最高收率达８２％的ＴＮＢＡ。     

基于频域Katz分形维数的快速盲频谱感知

针对目前频谱感知方法对噪声不确定性敏感、低信噪比下准确度较差和运算速度慢的问题,提出了基于频域Katz分形维数的快速盲频谱感知方法。该方法根据信号和噪声的频域Katz分形维数特征的不同来感知主用户的存在。Monte Carlo仿真结果表明,该方法具有对噪声功率不敏感、受调制参数影响小、低信噪比下准确度高和运算速度快的优点,并能有效克服盒维数方法对某些调制参数的信号无法感知的缺点,可用于低信噪比、噪声具有不确定性情况下的快速盲频谱感知。     

求非线性规划全局最优解的一个算法

首先给出了判别ｆ（ｘ）的极小值点ｘ０∈Ｄ是否为ｍｉｎ ｆ（ｘ）的最优解的充分必要条件,在此基础上,给出了求一元函数及多元函烽全局最优解的方法,此外,还给出了求一元函数极值的一个迭代算法。     

SC response characteristics of two kinds of coagulant

Automatic coagulant dosage control with streaming current (SC) technique is in troduced inthis paper. Aluminum and ferric coagulants are widely used in surface water treatment. The SC response characteristics of P-AiCI3 aluminum coagulant and P-FeCI3 ferric coagulant were investigated in this work. Bench-scale water treatment results were obtained from jar tests including rapid mixing,flocculation and undisturbed sedimentation. Results showed that aluminum coagulant is more sensitive than ferric coagulant to SC response.     

双典线凉水塔施工新工艺

双曲线凉水塔由现浇钢筋砼柱改预制钢筋砼柱，简壁模板曲线计算采用接近法退归模板长近似法计算，该法与传统方法不同，有计算简单，施工出的曲面圆滑流线度好，施工曲面与设计曲面间的吻合程度较高等优点；施工中利用结构自身强度承重，随着式三角架模板体系，将塔吊设置在塔体外侧，改变了以往井架设置在塔体外，人工供料的施工工艺。     

汽车潮中的另类声音

今年北京国际车展人潮汹涌,40万人次饱览了中国汽车工业的新趋势,使人感到中国离汽车时代真的不远了。 中国的汽车工业,无论是民族企业,还是合资企业,今年都在开足马力生产汽车。据统计,今年1～5月份累计生产各类汽车130万辆,比去年同期增加30.3％,销售汽车127.6万辆,同比增加27％,由于     

Optimized Parallel Cooperative Spectrum Sensing Strategy Based on Iterative Kuhn-Munkres Algorithm

Spectrum sensing is the key and premise of cognitive radio （ CR）. Current parallel cooperative spectrum sensing strategies have some problems, such as large number of cooperative secondary users and lack of consideration for the sensing overhead and the transmission gain. To solve those problems, an optimized parallel cooperative spectrum sensing strategy based on iterative Kuhn- Munkres （KM） algorithm was proposed. To maximize the total system profit, it considers the tradeoff between the sensing overhead and the transmission gain. Iterative KM algorithm was applied to obtaining the optimal assignment, which indicated when and which channels secondary users should sense. Furthermore, the required detection-probability was introduced to avoid unnecessary waste when the accuracy met the system requirement. Monte Carlo simulations show that the proposed strategy can obtain higher total system profit with fewer cooperative secondary users.     

关于数据流程图画法原则的研究

数据流程图是信息系统开发中的重要工具,利用它可以沟通开发者与使用者的思想。但如何画好数据流程图,目前并没有统一的标准。提出了画好数据流程图的8条重要原则,遵照这些原则,使数据流程图的编制者能更容易地画出正确的数据流程图,更准确地描述出一个信息系统的开发思路。