模糊PD控制器在电液伺服阀控制系统中的应用

应用模糊控制原理设计先导式电液伺服阀的模糊PD控制器,采用AMESim软件建立伺服阀的仿真模型,采用Simulink软件建立PD控制器和模糊PD控制器的仿真模型,通过AMESim/Simulink联合仿真得到伺服阀在两种控制方式下的阶跃信号响应曲线。仿真结果表明,与常规的PD控制器相比,模糊PD控制器能够提高控制精度,有效改善伺服阀的性能。     

Study on Sustainable Development Capability of Shandong Province

Based on the indicator system of Sustainable Development(SD), Shandong Province was selected as an example for assessment with AHP method and the standard year was 1978. The conclusion was that Shandong Province’s ability of SD was being strengthened step by step, and there were also some restrictive factors, and according to the basic conditions of Shandong Province, countermeasures and strategy of SD were put forward.     

Four-Parameter Signal Decomposition and Related Adaptive Time-Frequency Distribution

1. INTaODUCTIOMIn order to express the properties of the signal time-varying spectrum, we need to developa class of approaches to analyze signal in time and frequency domain simultaneously. Since1980's, the time-frequency analysis (TFA) methods, such as short time FOurier transform(STFT), Gabor expansion, wavelet transform and Wigner--Ville distribution (WVD), havebeen widely studied and implemellted, which provides powerful tools to analyze and processvarious signals in TF plane. T…     

It(O)型随机系统的仿真--离散相似法

研究Ｉｔｏ型随机系统的仿真，采用离莠相似法得到了Ｉｔｏ型随机系统数值计算的两种差分格式，分析了差分格式的精度和用于Ｉｔｏ型随机系统仿真的有效性，文末用实例演示了所得方法的应用。     

问号皮瓣修复圆形缺损25例

对于体表，特别是颜面部的手术，病人总是希望医生既能去除病灶，又能将疤痕减少到最少最小程度，以达到最大限度地不影响其局部形态及器官功能的目的。体表圆形或近似圆形的病灶在临床上较为常见，切除后如何较好地修复是整形美容外科领域一直探讨的问题。问号皮瓣修复圆...     

龙口褐煤对As（Ⅲ）的吸附特征

利用龙口褐煤作吸附剂对Ａｓ（Ⅲ）的单组分水溶液进行吸附研究，对吸附模型，吸时间，吸附剂用量以及温度、ｐＨ值对吸附的影响给予表征，结果表明：龙口褐对Ａｓ（Ⅲ）的静态等温吸附符合Ｆｒｅｕｎｄｌｉｃｈ等温方程。．     

土木工程专业课程体系建设及其学生适应性探讨

根据国家教育部1998年下达的新专业目录，结合广西建筑与交通土建行业的发展需要，对新的土木工程专业的培养目标和课程体系设置进行探讨，并就学生的学习适应性和社会适应性进行分析，进而提出一些对策．     

纳米材料的特异效应及其应用

纳米材料是一类具有重要理论价值和广阔应用前景的新型功能材料,被誉为21世纪最有前途的材料.本文阐述了这类材料的基本结构、特异效应、应用现状以及目前的研究进展.     

关于复杂现象的起源,描述和演化过程的哲学思考

复杂性起源于不同事物间的相互作用，并随着相互作用单元数目的增加而增加。对复杂系统行为的唯象描述可通过相互作用的微观分析与系统论思想方法的综合运用来进行。以能量耗散为基础的“活性”复杂系统，其演化过程是由多重态的产生机制与定态选择机制的协同耦合关系所决定的。     

Hydrogen Adsorption on Metal-Organic Framework MOF-177

This review summarizes the recent literature on the synthesis, characterization, and adsorption properties of meal-organic framework MOF-177. MOF-177 is a porous crystalline material that consists of Zn4O tetrahedrons connected with benzene tribenzoate (BTB) ligands. It is an ideal adsorbent with an exceptionally high specific surface area (BET4500 m2/g), a uniform micropore size distribution with a median pore diameter of 12.7 ?, a large pore volume (2.65 cm3/g), and very promising adsorption properties for hydrogen storage and other gas separation and purification applications. A hydrogen adsorption amount of 19.6 wt.% on MOF-177 at 77 K and 100 bar was observed, and a CO2 uptake of 35 mmol/g on MOF-177 was measured at 45 bar and an ambient temperature. Other hydrogen properties (kinetics and heat of adsorption) along with adsorption of other gases including CO2, CO, CH4, and N2O on MOF-177 were also be discussed. It was observed in experiments that MOF-177 adsorbent tends to degrade or decompose when it is exposed to moisture. Thermogravimetric analysis showed that the structure of MOF-177 remains intact at temperatures below 330℃ under a flow of oxygen, but decomposes to zinc oxide at 420℃.