基于PIC单片机的三相正弦波变频电源的设计

提出了一种基于PIC单片机设计的三相正弦波变频电源。样机实践证明,该电源切实可行、成本低廉,且具有输出频率可调、缺相保护、过流保护、不平衡保护等特点

The Research on the Optimization of Futures Hedging Model Considering Hedging Cost

商品制造者无时无刻不面临着其所需原材料和半成品价格波动带来的风险。当前国际原油、矿石、铜、铝等大宗商品价格的大幅波动以及近来国内汽油、棉花、粮食等商品价格的不断攀升，让各类企业蒙受着严重的价格风险。本文就此问题介绍运用期货套期保值即买卖商品期货的方法来应对商品价格波动的风险。另外，研究期货套期保值有助于扩大套保者队伍，繁荣发展期货市场，加快市场成熟程度，为期货套保者提供较为理性的保值策略，并提高其风险管理能力。 目前的套期保值理论从不同角度优化期货套期保值策略，但探讨结合交易费用和保证金机会损失等实际期货交易因素的文献还比较少，本文通过深入了解期货市场交易的实际操作流程，分析期货套期保值...Commodity producers never fail to face such price fluctuation risks of raw materials and semi-finished products.The price fluctuations of current international crude oil, ore, copper, aluminum and other commodities, as well as prices climbing of recent domestic gasoline, cotton, grain and other commodities all cause enterprises suffering from severe price risk. This paper intends to deal with the ...学位：理学硕士院系专业：数学科学学院数学与应用数学系_概率论与数理统计学号：1902009115225

The Design of the Vapour Generator Based on the Grading PIDs

常规的灭菌器工作时需外配一台蒸汽发生器,导致灭菌系统结构复杂价位高。文章介绍一种装配于灭菌器内部的小型蒸汽发生器,该蒸汽发生器采用分段PID控制,文章还介绍了该蒸汽发生器的软硬件设计。Common sterilizer requires one vapor generator when it was operated.So the system's structures are very complex and price is expensive.This article introduces a kind of tiny vapor generator,it can be assembled in germ-killer,it is controlled by the grading PIDs.This article also introduces the software design and hardware design of the vapor generator.福建省科技厅资助项目(2007F5100

Design of auto feed-sprinkler based on PIC microcontroller

目前鉴于我国渔业养殖设备比较落后,介绍了在渔业养殖上广泛应用的自动喷料机的软、硬件设计。该设计具有可靠性高、能定时定量喷洒饲料、喷料均匀、喷料距离远、避免饲料浪费等特点。At present,measurement and equipment of fishery is fall behind in our country. The software design and hardware design of auto feed-sprinkler are introduced.The auto feed-sprinkler is extensive in fishery. The auto feed-sprinkler features, high reliability, periodical sprinkling feed, uniform sprinkling feed, far sprinkling feed and saving feed etc

Pulsating Vacuum Sterilizer Based on Digital PIDs

长期以来，我国各企业生产的灭菌器是手工操作下排汽式的，存在自动化程度低、消毒效率低、消毒效果差的缺点。在研究学习前人设计的基础上，设计了基于数字PID控制的脉动真空灭菌器，该产品已行销全国，实践证明该灭菌器自动化程度高、消毒效率高、消毒效果达到欧洲B级标准。 论文在总结前人研究的基础上，将蒸汽发生器集成到灭菌器内部，简化消毒系统的复杂程度和降低了成本。该蒸汽发生器为小型铝合金构造，内含电热丝，采用数字PID控制蒸汽发生器的工作温度，通过合理选择PID的参数，获得良好的控制效果。论文详细介绍了灭菌器的机械构造、工作过程、控制系统软硬件设计。硬件设计以PIC16F74单片机为核心，配以键盘、LC...The sterilizers in China at present exhibit many deficiencies, such as the low level of automation and the inefficient effect of disinfection. Based on the previous work, we design the digital PID-based pulsating vacuum sterilizers, which have been sold all over the country. It has proved that this kind of sterilizers appear to be more automated, more efficient. Moreover, they have met the Level B...学位：工程硕士院系专业：信息科学与技术学院自动化系_控制工程学号：X20043102

实践概念与物质概念的关系三议——兼评实践本体论

实践的客观性和能动性源于物质的客观性和辩证性 ,实践的受动性和受制约性源于物质的客观性和规律性 ,实践本体论颠倒了二者的关系。由此必然导致唯我论。马克思主义哲学的创立有研究和表述两方面。从研究即发生学的角度看 ,唯物史观在先 ,因而实践范畴在先 ;从表述的逻辑看 ,则是物质范畴在先 ,实践范畴在后。自然界在时间上和物质范畴在逻辑上的先在性 ,并不会否定实践的重要性和实践范畴的核心地位 ,就像《资本论》的商品范畴的先在性并不否定剩余价值范畴的核心地位一

SNA与SEEA的环境资产比较分析

环境资产的定义是环境经济一体化核算体系 (SEEA)的基础。作为国民经济核算体系 (SNA)的附属帐户 ,SEEA定义的资产与 SNA不同。SNA着眼于经济资产 ,而非环境资产 ,尽管 SNA存在一些限制 ,但其仍包含大量重要的环境资产。并通过对这两个体系内的环境资产进行比较分析 ,可以更好地理解 SEEA环境资产的实质内容。文章首先定义环境资产的意义 ,然后结合 SNA的经济资产分类 ,分析SEEA的环境资产分类

The Sufficient Condition of Finite-time Stabilityof Linear Switched Systems

切换系统限时稳定问题正被广泛研究.文章提出一种新的充分条件,用于判决一般线性切换系统的限时稳定性.Finite-time stability of switched systems is studied.A new sufficient condition is proposed to judge the finite-time stability for general linear switched systems

An Empirical Study on Influencing Factors of High M2/GDP in China

通过建立多元线性回归模型对我国M2/GDP过高的影响因素进行实证分析,结果表明,金融市场不完善、总储蓄率高居不下、广义货币流通速度急剧下降以及国家债务负担沉重是我国M2/GDP畸高的主要原因。应从加快金融市场的改革与监管、鼓励金融创新、发展资本市场、维持适度的债务规模以及鼓励公众使用其他投资方式等方面遏制M2/GDP过高所带来的风险。Through establishing multi linear regression model,this thesis makes empirical analysis on the influencing factors of high M2/GDP in China.Empirical evidences reveal that the main causes of unusual high M2/GDP in China are: undeveloped financial market,high deposit ratio,low velocity of circulation of broad money and heavy national debt.To limit the risk of too high M2/GDP,effects should be made in several aspects: speed up reform and supervision of financial market,encourage financial innovation,develop capital market,keep moderate debt level,and encourage publics to use other ways of investment etc