网络CAD技术简述

网络及其衍生技术的迅速发展使得传统CAD发生了质的飞跃,正衍变成为一门新的学科。本文针对CAD技术的一个新的发展－网络CAD进行了全面的概述。首先介绍了背景与产生原因,随后说明了相关概念与应用领域。最后阐述了主要研究内容与发展趋势。     

N（2）—乙酰基—9—[（2—乙酰氧乙氧基）甲基]鸟嘌呤的制备工艺条件的研究

人工神经网络由于其具有较好的自组织,自学习,多输入,多输出的能力,在预测方面已取得了广泛应用,本文将BP人工神经网络应用于N（2）－乙酰基－9－[2(2-乙酰氧乙氧基）甲基鸟嘌令的制备工艺条件快速 准确地确定工艺影响参数及其范围的问题。     

网络并行计算平台新架构*

网络并行计算的编程要求设计者对任务的分解、分配及子任务间的交互等问题有更高的技术。给出了在网络并行计算的一种新平台,用户只需提交数据和对它的操作即可。     

~(123)I的制备及其快速标记

本文报道了在原子能研究所1.2米回旋加速器上用26MeV的α粒子流轰击天然丰度的锑靶,通过~(121)Sb(α,2n)~(123)I反应,以铜基铂吸附剂对碘选择性吸附法分离和浓集~(123)I,制得Na~(123)I溶液。Na~(123)I的放化纯度大于99％。在辐照结束时,其主要放射性杂质~(124)I占产品~(123)I的比率小于1.4％,整个分离过程不到4小时即可完成,总的化学收率在95％以上。所得产品用冠醚为溶剂,对肾上腺显影剂6-碘甲基-19-去甲胆固醇以及心脏显影剂ω-~(123)I-十七烷酸进行了快速标记。结果表明,与国内外现用的标记方法相比较,该法具有快速、简便、产额高等优点。     

略论盐城“水利梦”

认真学习领会习近平总书记提出的"中国梦",结合实际,论述了如何转化为干好盐城水利工作的动力,见诸行动,出实策、鼓实劲、办实事,力争实现盐城的"水安全梦"、"水资源梦"、"水环境梦"、"水生态梦"、"水经济梦"和"水文化梦",同心践行和助力"中国梦",真正实现人水相依、和谐共生、良性循环、全面繁荣。     

两种水轮发电机组开机控制技术的比较及优化

本文建立了水轮发电机组仿真模型,并以某电站的水流特性、机组惯性等实际参数作为仿真模型参数,着重研究水轮发电机组的两种开机控制规律,分析了原有以空载开度为限制的机组开机控制技术,提出以恒转速变化率为控制目标的机组开机控制技术,并将两种开机控制技术进行了仿真比较。通过仿真波形分析比较表明,两种开机控制技术各自具有的优越动态性能。在工程实践中,将这两种开机控制技术都应用到水轮机调速器开机程序中,可以根据水电站现场对开机动态性能的不同要求在停机态切换两种开机控制流程。     

Study of partial discharge characteristics at repetitive square voltages based on UHF method

Due to overvoltage produced by inverter output,inverter-fed motor insulation systems often experience fast electrical aging process,especially when partial discharge(PD) is incepted.Before putting into use,the PD detection should be performed on inverter-fed motors at repetitive square voltages to avoid the PD caused insulation deterioration when the motors are collected to inverters having specific characteristics.However,unlike PD tests at AC/DC voltages proposed in IEC 60270,the PD detection at repetitive square voltages is much more complex because of serious interference generated by impulse generator.To solve the problem,ultra-high frequency(UHF) method seems recommendable for its preferable signal-to-noise ratio(SNR).The chief aim of this study is to investigate PD pulse and statistical characteristics of turn-to-turn insulation for inverter-fed traction motors.A square-shaped Archimedes antenna,specially designed for the PD detection at repetitive square voltages of fast rise times,was used to perform PD tests on turn-to-turn insulation models.Time and frequency analysis results indicate that energy component of generator disturbance and PD pulses are mainly distributed in the 0-0.5 GHz and 0.6-1.5 GHz range,respectively.Based on the results,suitable filter was designed for power disturbance suppression.Additionally,resorting to the sensor unit(i.e.antenna and filter) and the PD test system,the PD statistical features at square voltages of different frequencies were obtained.Experimental results show that higher frequency will give rise,statistically,to PD of lower magnitudes distributing at smaller phases.A reasonable interpretation of this phenomenon was presented.Lastly,according to the PD statistical features,some suggestions for the PD detection system design,generator parameter optimization and the PD pulse extracting were given.The results of this work would be beneficial to the increase of the sensitivity when performing the PD detection on insulation systems for inverter-fed motors at repetitive square voltages and thus,improving the reliability of inverter-fed motors.     

新疆某水利枢纽泄洪闸闸墩温控 防裂反馈分析

Based on the basic theory of temperature field and stress field for mass concrete, a feedback calculation for the temperature control simulation is made in accordance with the specific characteristics of the pier of the flood discharge sluice for a water control project in Xinjiang. It is known through the calculation that the adoptions of both the measure to alleviate the temperature difference between the inner and the outer concrete of the pier during the early period and the measure of the following-up temperature insulation for the concrete are the favorable methods to prevent the cracking of the pier concrete, and then this study result can provide references for the related project concerned.     

某铁路π形梁桥的荷载试验研究

以某铁路桥为工程背景,通过结构计算、现场检测、荷载试验等工作,对铁路桥梁的荷载试验过程进行详细阐述,评估受检π形梁的工作性能和承载能力。结果表明,受检π形梁的承载能力能够满足设计荷载等级的要求。工程为π形梁的后期养护及维修提供了基础依据,对同类型铁路桥梁的检测及其承载能力评价有一定的参考价值。