赣方言区普通话水平测试中的语音偏误调查

本文在对赣方言区普通话水平测试成绩调查的基础上,分析了赣方言区考生常见的语音偏误,以及各等级的偏误特点,指出了调查分析结果对赣方言区普通话水平测试和普通话教学的积极作用。     

弧形齿联轴器承载能力的有限元分析

以弧形齿联轴器的齿轮副为研究对象,基于弧形齿的加工原理,对齿轮副内外啮合齿轮建立三维模型,再将模型导入有限元软件中,分析内外齿轮在不同轴间倾角下的应力分布,并对齿轮进行强度校核,最终得出弧形齿联轴器的承载能力与内外齿轮轴间倾角的关系。     

集装箱立转设备的结构设计

本文阐述了集装箱立转设备的结构设计,使吊装及装箱均在同一次操作中完成,并可实现集装箱双向竖立,无须倒动集装箱或调转运输车方向,使用极其简洁方便,较大地提高了干散货集装箱装运效率及效益.可以为集装箱购买提供参考.     

电动汽车新型线控制动单元及其控制系统

针对电动汽车全电驱动特性,为提高其制动性能,设计了一种基于电磁直线执行器的全新线控制动单元——直驱电液制动单元.介绍了该制动单元的结构和原理,以某型制动器为基础,完成了样件改装和试制工作,并基于TMS320F2812数字信号处理器建立了制动单元控制和驱动系统,同时设计了双闭环抗干扰控制算法调控其制动力.试验结果表明,直驱电液制动单元响应迅速,能够准确调控制动力,具有良好的应用前景.     

Synthesis and optical properties of turquoise- and green-colored brownmillerite- type Ba2In2-x-yMnxAlyO5+x codoped with manganese and aluminum

Brownmillerite-type oxides Ba₂In_2-x-yMn_xAl_yO_5+x (0 ≤ x ≤ 0.6, 0 ≤ y ≤ 0.5) were prepared at 1300°C through solid-state reaction. X-ray diffraction (XRD) analysis showed that the structure symmetry evolved from orthorhombic to cubic with increasing Mn and Al contents. When y was greater than 0.3, peaks associated with small amounts of BaAl₂O₄ and Ba₂InAlO₅ impurities were observed in the XRD patterns. When substituted with a small amount of Mn (x ≤ 0.3), the Ba₂In_2-x-yMn_xAl_yO_5+x samples exhibited an intense turquoise color. The color changed to green and dark-green with increasing Mn concentration. UV–vis absorbance spectra revealed that the color changed only slightly upon Al doping. The valence state of Mn ions in Ba₂In_2-x-yMn_xAl_yO_5+x was confirmed to be +5 on the basis of X-ray photoelectron spectroscopic analysis. According to this analysis, the intense turquoise color of the Ba₂In_2-x-yMn_xAl_yO_5+x samples is rooted in the existence of Mn5+; thus, the introduction of Al does not affect the optical properties of the compounds.     

Effects of stress ratio on the temperature-dependent high-cycle fatigue properties of alloy steels

This paper addresses the effects of stress ratio on the temperature-dependent high-cycle fatigue (HCF) properties of alloy steels 2CrMo and 9CrCo, which suffer from substantial vibrational loading at small stress amplitude, high stress ratio, and high frequency in the high-temperature environments in which they function as blade and rotor spindle materials in advanced gas or steam turbine engines. Fatigue tests were performed on alloy steels 2CrMo and 9CrCo subjected to constant-amplitude loading at four stress ratios and at four and three temperatures, respectively, to determine their temperature-dependent HCF properties. The interaction mechanisms between high temperature and stress ratio were deduced and compared with each other on the basis of the results of fractographic analysis. A phenomenological model was developed to evaluate the effects of stress ratio on the temperature-dependent HCF properties of alloy steels 2CrMo and 9CrCo. Good correlation was achieved between the predictions and actual experiments, demonstrating the practical and effective use of the proposed method.     

甲基异柳磷气相色谱定量法

甲基异柳磷原油用气相色谱法测定,其色谱条件如下:不锈钢柱1m×3mm、柱内填充物为5%OV-3涂于ChromosorbW-HP60—80目担体,以氮气作载气,柱温190℃,用氢火焰检测器,癸二酸二正丁酯作内标,测定误差<±1.2%.     

RS码和P—TCM级联性能

目的 为取得较高的频带效率和较大的编码增益同时降低编码和译码复杂度。方法 将里德索罗门（ＲＳ）码与带宽有效的Ｐ－ＴＣＭ８ＰＳＫ和１６ＰＳＫ码进行级联,并在高斯信道上对其性能进行分析和计算机模拟。结果 在误比特率Ｐｂ＝１０＾－４时,级联编码系统比单个码Ｐ－ＴＣＭ系统多获得１ｄＢ编码增益,在误比特率Ｐｂ＝１０＾－７时,级联编码系统比Ｐ－ＴＣＭ系统多获得３ｄＢ编码增益。结论 随着Ｐｂ下降,ＲＳ码与Ｐ－Ｔ     

8.0kbit／sACELP声码器的GSM平台仿真

研究恶劣传输环境下８．０ｋｂｉｔ／代数码激励线性预测声码器的译码算法的改进及其在ＧＳＭ典型信道的传输性能。方法在集成软件仿真平台中引入稳信道编码模块,以消除衰落噪声和高斯噪声的影响,并完成ＡＣＥＬＰ声码器到ＧＳＭ全速率语音业务信道（ＴＣＨ／ＦＳ）的速率适配任务;在ＡＣＥＬＰ译码器中引入错误帧隐藏单元（ＥＣＵ）,以提高恶劣信道环境下的合成语音质量。结果与结论错误隐藏单元与相应的高效稳健的信道编码相结     

Influences of double aerial CO2 concentration on plant root surface area and viability and infection intensity of vesicular-arbuscular mycorrhizal fungi

Using recently developed methods for root research, an investigation initiated concerning effects of doubled atmospheric CO2 concentration on root surface area and infection of vesicular-arbuscu-lar mycorrhizal (VAM) fungi in seedlings of maize, wheat and soybean. Results showed that doubled CO2 concentration significantly extended root system surface area and promoted VAM fungal infection intensity and viability. However, interspecific variation existed in these responses. It is suggested that plant community succession would be changed due to altered characteristics of roots among species in the future climate.