美国研究型大学人才培养模式研究

本文首先分析了美国研究型大学的课程教学的特点,通过对美国研究型大学人才培养质量监督体系进行系统比较的基础上,剖析了美国人才培养体系的特色和相互差异,最后借鉴美国研究型大学创新型人才培养途径的成功经验,对我国高校人才培养模式的改革提出了一些思考和建议。

中美高校机械工程实验课程设置与人才培养模式的比较研究

选择中美典型高校为样本,比较研究两国高校机械工程类创新人才的实验教学培养模式、实验课程设置及实验室管理。针对机械工程实验教学中的薄弱环节,就如何提高其教学质量、制定实施细则,从教学理念、计划、内容、方式上不断丰富和规范我国机械工程实验教学,为高校及其主管部门进行基于大学生实践创新能力培养的机械工程类实验教学改革及实验室建设提供具体、可操作性强的实施方案。

无线电能传输技术综述及应用前景

传统的电能传输方式大多通过导线或插座将电能传输到终端产品。这种传输方式会带来摩擦,易产生电火花等问题,从而影响电气设备的安全可靠性。而无线电能传输技术能使我们摆脱传统的电能传输方式,通过电磁感应、高频振荡、电磁共振、微波等多种形式实现非接触式的新型电能传输。文章讲述了无线电能传输技术在国内外的研究现状,详细叙述了现有理论框架下的四种无线电能传输技术,并比较了四种技术的特点和应用领域。最后,阐述了新型无线电能传输技术的应用技术领域。

双凸极电励磁发电机系统非奇异终端滑模控制器的设计与仿真

针对双凸极电励磁发电机调压系统,提出了一种非奇异终端滑模控制的调压控制策略。介绍了双凸极电励磁发电机的结构,并构建了数学模型。在此基础上,详细分析了基于非奇异终端滑模控制的调压器工作原理,给出了相应的滑模面方程与滑模控制律。通过李雅普诺夫稳定性方程和固定PWM控制载波交截等限制条件,给出了控制律系数的计算选取方法。基于电磁有限元瞬态分析技术与控制电路构建了"场-路"联合仿真系统,并对发电机的稳态与动态运行性能进行了仿真,结果表明基于非奇异终端滑模控制的双凸极电励磁发电机调压系统具有良好的稳态性能和优良的动态特性,具有输出电压静差和纹波小、动态恢复时间短和动态输出电压变化小的优越性能。

基于新颖自适应方法的微振动陀螺仪研究

针对微振动陀螺仪存在的制造误差以及本身参数易受环境影响,从而导致输入角速率难以测量的问题,提出了一种新颖的自适应方法来获取输入的角速率以及微陀螺仪的各项参数。该方法通过对微陀螺仪的数学模型进行变换,设计出一种新型的自适应辨识器,在线实时更新微陀螺仪角速率估计值。估计值的自适应律基于李雅普诺夫方法设计,保证了辨识器的全局渐近稳定性。在控制输入包含2个不同频率分量的的条件下,辨识器的各项估计值输出都能够渐近收敛到各自的真值。采用M atlab/simu link来搭建仿真模型,仿真实验的结果验证了该自适应方法对微陀螺仪角速率等各项参数测量的有效性和可靠性。

神经网络控制的应用和发展

神经网络控制的应用和发展ＴｈｅＡｐｐｌｉｃａｔｉｏｎａｎｄＤｅｖｅｌｏｐｍｅｎｔｏｆＮｅｕｒａｌＮｅｔｗｏｒｋＣｏｎｔｒｏｌ●费峻涛鲍远律朱民杨梅ＦｅｉＪｕｎｔａｏＢａｏＹｕａｎｌｕＺｈｕＭｉｎＹａｎｇＭｅｉ１引言神经网络首先用于解决模式识别问题。随...

Yield of Ozone,Nitrite Nitrogen and Hydrogen Peroxide Versus Discharge Parameter Using APPJ Under Water

Discharge plasma in and in contact with water can be accompanied with ultraviolet radiation and electron impact, thus can generate hydroxyl radicals, ozone, nitrite nitrogen and hydrogen peroxide. In this paper, a non-equilibrium plasma processing system was established by means of an atmospheric pressure plasma jet immersed in water. The hydroxyl intensities and discharge energy waveforms were tested. The results show that the positive and negative discharge energy peaks were asymmetric, where the positive discharge energy peak was greater than the negative one. Meanwhile, the yield of ozone and nitrite nitrogen was enhanced with the increase of both the treatment time and the discharge energy. Moreover, the pH value of treated water was reduced rapidly and maintained at a lower level. The residual concentration of hydrogen peroxide in APPJ treated water was kept at a low level. Additionally, both the efficiency energy ratio of the yield of ozone and nitrite nitrogen and that of the removal of p-nitrophenol increased as a function of discharge energy and discharge voltage. The experimental results were fully analyzed and the chemical reaction equations and the physical processes of discharges in water were given.

Regulation characteristics of oxide generation and formaldehyde removal by using volume DBD reactor

Discharge plasmas in air can be accompanied by ultraviolet（UV） radiation and electron impact,which can produce large numbers of reactive species such as hydroxyl radical（OH·）,oxygen radical（O·）,ozone（O3）,and nitrogen oxides（NOx）,etc.The composition and dosage of reactive species usually play an important role in the case of volatile organic compounds（VOCs） treatment with the discharge plasmas.In this paper,we propose a volume discharge setup used to purify formaldehyde in air,which is configured by a plate-to-plate dielectric barrier discharge（DBD） channel and excited by an AC high voltage source.The results show that the relative spectral-intensity from DBD cell without formaldehyde is stronger than the case with formaldehyde.The energy efficiency ratios（EERs） of both oxides yield and formaldehyde removal can be regulated by the gas flow velocity in DBD channel,and the most desirable processing effect is the gas flow velocity within the range from2.50 to 3.33 m s^-1.Moreover,the EERs of both the generated dosages of oxides（O3 and NO2） and the amount of removed formaldehyde can also be regulated by both of the applied voltage and power density loaded on the DBD cell.Additionally,the EERs of both oxides generation and formaldehyde removal present as a function of normal distribution with increasing the applied power density,and the peak of the function is appeared in the range from 273.5 to 400.0 W l-1.This work clearly demonstrates the regulation characteristic of both the formaldehyde removal and oxides yield by using volume DBD,and it is helpful in the applications of VOCs removal by using discharge plasma.

Water Content Effect on Oxides Yield in Gas and Liquid Phase Using DBD Arrays in Mist Spray

Electric discharge in and in contact with water can accompany ultraviolet（UV）radiation and electron impact, which can generate a large number of active species such as hydroxyl radicals（OH）, oxygen radical（O）, ozone（O_3） and hydrogen peroxide（H_2O_2）. In this paper, a nonthermal plasma processing system was established by means of dielectric barrier discharge（DBD）arrays in water mist spray. The relationship between droplet size and water content was examined,and the effects of the concentrations of oxides in both treated water and gas were investigated under different water content and discharge time. The relative intensity of UV spectra from DBD in water mist was a function of water content. The concentrations of both O_3 and nitrogen dioxide（NO_2） in DBD room decreased with increasing water content. Moreover, the concentrations of H_2O_2, O_3 and nitrogen oxides（NOx） in treated water decreased with increasing water content,and all the ones enhanced after discharge. The experimental results were further analyzed by chemical reaction equations and commented by physical principles as much as possible. At last,the water containing phenol was tested in this system for the concentration from 100 mg/L to9.8 mg/L in a period of 35 min.

Atmospheric Pressure Plasma Jet in Organic Solution:Spectra,Degradation Effects of Solution Flow Rate and Initial pH Value

The organic compounds of p-nitrophenol （PNP） solution was treated by the active species generated in a stirred reactor by an atmospheric pressure plasma jet （APPJ）. The emission intensities of hydroxyl （OH）, oxygen （O）, nitric oxide （NO）, hydrogen （H） and molecular （N2） were measured by optical emission spectroscopy （OES）. The relations between the flow rates of the PNP solution and degradation, the degradation effects and initial pH value of the solution were also investigated. Experimental results show that there exist intense emissions of O （777.1 nm）, N（337.1 nm）, OH （306-310 nm） and NO band （200-290 nm） in the region of plasma. Given the treatment time and gas flow rate, the degradation increased as a function of discharge energy and solution flow rate, respectively. The solution flow rate for the most efficient degradation ranged from 1.414 m/s to 1.702 m/s, and contributed very little when it exceeded 2.199 m/s. This indicates the existence of diffusion-controlled reactions at a low solution flow rate and activation- controlled reactions at a high solution flow rate. Moreover, increasing or decreasing the initial pH value of neutral PNP solution （pH=5.95） could improve the degradation efficiency. Treated by APPJ, the PNP solutions with different initial pH values of 5.95, 7.47 and 2.78 turned more acidic in the end, while the neutral solution had the lowest degradation efficiency. This work clearly demonstrates the close coupling of active species, photolysis of ultraviolet, the organic solution flow rate and the initial pH value, and thus is helpful in the study of the mechanism and application of plasma in wastewater treatment.