不锈钢网架(壳)技术及其应用

本文总结了多年来不锈钢网架的研究成果 ,并介绍了部分不锈钢网架的工程应用     

浙江省地方水电在改革中加快发展

浙江省缺煤少油，山地面积约占70％，雨量充沛，水力资源比较丰富，是我省宝贵的一次能源．截至1997年，大中小水电装机累计290余万kw，其中地方中小水电计123万kw，是华东电网的主要水电电源之一，不仅为浙江省提供了再生洁净的电能，也为华东电网提供了紧缺的顶峰电力．目前，我省水电资源可开发规模尚有400余万kw，开发利用有着广阔的前景．建国以来，浙江省地方水电的发展为山区经济振兴和农村脱贫致富作出了重大贡献．“七五”、“八五”期间，我省有26个县（市）圆满完成了国务院下达的第一、第二批农村水电初级电气化县建设任务，对…     

学习新版建筑工程施工质量验收规范的体会

结合新版建筑工程施工质量验收规范的学习和施工实践 ,介绍了新版标准与旧标准的差异和特点 ,并就如何贯彻实施新标准、准确掌握检验批等问题作了分析 ,提出了执行中的相关注意事项。     

用科学发展观推进水利“十个转变”

树立和落实科学发展观，除不断深化对科学发展观的科学性、必然性和战略性、指导性的认识，不断增强坚持和落实科学发展观的自觉性和坚定性外，更重要的是要将科学发展观付诸实践，见诸行动，贯穿到促进经济社会发展和推动改革开放的各项工作中去，在实践中将科学发展观转化为强大的物质力量。水利行业贯彻和落实科学发展观，关键在于认清形势，立足实际，把握重点，明确方向，在扎实推进“十个转变”上下功夫。     

Flammability and thermal stability studies of ABS/Montmorillonite nanocomposite

Acrylonitrile–butadiene–styrene (ABS)/montmorillonite nanocomposites have been prepared using a direct melt intercalation technique by blending ABS and organophilic clay of two different particle sizes: OMTa (5 µm) and OMTb (38 µm). Their structure and flammability properties were characterized by X‐ray diffraction, high resolution electronic microscopy (HREM), thermogravimetric analysis (TGA) and cone calorimeter experiments. The results of HREM showed that ABS/5 wt% OMTa nanocomposite was a kind of intercalated–delaminated structure, while ABS/5 wt% OMTb nanocomposite was mainly an intercalated structure. The nanocomposites showed a lower heat release rate peak and higher thermal stability than the original ABS by TGA and cone calorimeter experiments. Also, the intercalated nanocomposite was more effective than an exfoliated–intercalated nanocomposite in fire retardancy. Copyright © 2003 Society of Chemical Industry     

Nonlinear dynamic characteristics of piezoelectric bending actuators under strong applied electric field

Dynamic characteristics of piezoelectric bending actuators under low and high electric fields are studied using the asymptotic theory of nonstationary vibrations. The proposed nonlinear model predicts the changes in fundamental resonant frequencies of the piezoelectric cantilever. The predicted resonance amplitude of the tip deflections of the piezoelectric actuators, which increases with the increase in the magnitude of the electric field, well agrees with the experimental results. Additionally, the decrease in the mechanical quality factor with the increase in the electric field, the tip deflection of piezoelectric actuators near resonance frequency,and the amplitude of the tip deflection at the fundamental vibration tone under an applied electric field varying with time have also been obtained using the present model.     

浅析硫磺回收装置中的自动控制设计

大规模高含硫原油的炼制工艺必须配套设置脱硫和硫磺回收装置。笔者针对硫磺回收装置的特点,为确保装置的安全平稳运行,提出了该装置自动控制设计中需要严格监控的工艺参数及重点部位,叙述了仪表选型原则和精确测量与控制的原理和方法。     

Accurate higher-order analytical approximate solutions to nonconservative nonlinear oscillators and application to van der Pol damped oscillators

In general, this paper deals with general nonlinear oscillations of a nonconservative and single degree-of-freedom system with odd nonlinearity and, in particular, it presents accurate higher-order analytical approximate solutions to van der Pol damped nonlinear oscillators having odd nonlinearity and the Rayleigh equation. By combining the linearization of the governing equation with harmonic balancing and the method of averaging, we establish accurate analytical approximate solutions for the general weakly damped nonlinear systems. Unlike the classical harmonic balance method, simple linear algebraic equations instead of nonlinear algebraic equations are obtained upon linearization prior to harmonic balancing. The combination of these two methods results in very accurate transient response of the periodic solution. In addition and for the first time, this paper also presents a method for deducing fourth-, fifth- and higher-order linearized governing equations from the lower-order equations without the requirement of formulating the problem from the first principle. Three examples including the van der Pol damped nonlinear oscillator are presented to illustrate the excellent agreement with approximate solution using the exact frequency.