基于SoundBlaster声卡的数据采集系统

目的 在对SoundBlaster声卡性能特点分析的基础上,利用SoundBlaster声卡建立了数据采集系统的硬件电路和软件结构。方法 对采集过程中所遇到的隔直问题,提出切实可行的解决办法。结果与结论 具有一定的实践参考意义。     

用电脑听高保真音乐选用什么声卡更好

用电脑听高保真音乐,声卡的选择尤为重要.文中介绍了声卡及其输出接口的选择的具体方法、独立声卡的用料与做工,并推荐了性能较好的声卡和输出接口,以及外部音响设备及其连接方式.     

几款电脑Hi-Fi的解码器

大家之所以这么认为只是一般电脑声卡在数模转换的模拟部分水准比Hi-Fi差太多.但这只要外接好的解码器就行了.用同轴输出的解码器接声卡或带USB接口的解码器(多用于笔记本,解码器其实就是一个高级的声卡),使电脑(包括PC,MAC系统)Hi-Fi渐渐流行起来.通过解码器驳接到功放,这是PC Hi-Fi最佳音源效果.     

专业声卡的选购

在《音响技术》2006年第11期和第12期刊登的《解析专业声卡》,从声卡的特征、性能、功用等整体方面重点介绍了市场上的主流声卡。本文中,则是通过介绍声卡的主要配制音效芯片和编解码器芯片,来反映主流声卡的功能与素质。最后介绍了如何安装和改装声卡,使声卡的功效获得进一步的提高。     

基于Matlab的数据采集系统设计

利用Matlab软件及其数据采集工具箱,设计基于声卡的数据采集系统.分析了用Matlab语言编程实现该数据采集与分析系统的过程,阐述了对采集到的语音信号加噪后进行滤波的设计方法.系统运行表明:通过计算机声卡能够自动录音和自动保存;用户可在主界面预览时域图形和频谱图,滤波处理后可实时显示和重放录音.     

用电脑听高保真音乐选用什么声卡更好

用电脑听高保真音乐,声卡的选择尤为重要。文中介绍了声卡及其输出接口的选择的具体方法、独立声卡的用料与做工,并推荐了性能较好的声卡和输出接口,以及外部音响设备及其连接方式。     

声卡常见故障诊断与维护

在计算机系统中对音质影响最大的配件当是声卡与音箱,至于CPU、内存之类的配件,到显得无关紧要。声卡是声音之源,负责信号的处理,它的性能高低与输出的音频信号质量关系重大。一旦声卡出现故障,计算机将变成一个"哑巴"。     

解析专业声卡（一）

声卡及其发展历程声卡是计算机与外部音频设备进行信号交换的媒介,是计算机处理声音信号的主要硬件工具。对于普通计算机,配备价格低廉的板载声卡,声音质量能基本满足听音乐、看电影的需要。正是声卡的出现,使计算机迈出多媒体人机交流的第一步,拓展了计算机的使用领域和普及。1984年,英国Adlib Audio公司推出第一款声卡,与现在的声卡相比,不论在音质上还是在功能上都有着较大的差距,而且不能处理数字音频信号,其声音的表现能力还不如今天的手机铃声,然而它的出现却具有历史性的意义。当时的声卡采用的是ISA标准。ISA(Industry Standard…     

USB外置声卡特点及主流产品（一）

剖析了USB声卡的工作原理及特点,特别是较内置声卡的优势。并介绍了目前市场上几类不同应用的主流USB声卡的特点及适用范围。     

USB外置声卡特点及主流产品（二）

剖析了USB声卡的工作原理及特点,特别是较内置声卡的优势。并介绍了目前市场上几类不同应用的主流USB声卡的特点及适用范围。     

Modelling a Plunging Breaking Solitary Wave with Eddy-Viscosity Turbulent SPH Models

Breaking waves can run up at the shoreline, inundating coastal regions and causing large property damage and loss of life. In order to proceed to the design of sea defence structures and estimate the possible damage resulting from sea submersion due to a tsunami for instance, it is thus crucial to understand these phenomena. However, due to the mathematical difficulties caused by the complexities of the fluid motion associated with breaking wave, a fully theoretical approach is not possible. Thus most of the investigations regarding breaking waves are experimental and numerical. Some methods were recently developed to perform such simulations, among them Volume Of Fluids (VOF) and Lagrangian methods. In this paper, the gridfree Smoothed Particle Hydrodynamics (SPH) is used. SPH is preferencially used in CFD to simulate complex flows with one or several convoluted free surfaces. Indeed, this type of flows would require distorted meshes with Eulerian finite difference methods or very fine meshes with VOF. The ability of SPH to reproduce a plunging breaking solitary wave and to simulate the different stages of its process is herein investigated. Since breaking waves are characterised by high distorsion, turbulence modelling plays a crucial role in such simulations. Therefore, the turbulence models developed by the authors and presented in earlier publications [\relax \begingroup \catcode `\ 12\relax \catcode `\\12\relax \catcode `\$12\relax \catcode `\&12\relax \catcode `\#12\relax \catcode `\^12\relax \catcode `\_12\relax \catcode `\%12\relax \catcode `\~12\relax \endgroup \relax \cite *{dv_ri:2006}] are here applied. The results, compared to experiments, are on the whole satisfactory, specially the simulation of the splashup phenomenon. Moreover, it is shown that turbulence modelling has a strong influence on the quality of the results.     

关于用多项式的单调序列逼近

本文证明,如果f∈C[0,1]不是多项式,则有n次多项式Pn(x)与Qn(x)使得在[0,1]上Qn(x)相似文献   

Role of $${\varvec{\alpha}} \to {\varvec{\varepsilon}} \to {\varvec{\alpha}}$$ α → ε → α phase transformation on the spall behavior of iron at atomic scales

Journal of Materials Science - Shock compression of iron microstructures above a threshold stress results in a $$\alpha \left( {BCC} \right) \to \varepsilon \left( {HCP} \right)$$ transformation,...     

一个分析不等式的改进

对于一切n=1,2,…和实数x,不等式∑nk=1(-1)kksinkx≤|x|成立,这个不等式改进了被收录在多种文献[1,2]中的相关不等式.     

圆波导界面电磁场的传播特性

从麦克斯韦方程及边界条件出发对含有两种不同介质的金属波导管进行了研究 ,得到特征方程 (γ1ε2 -γ2 ε1) 2 (μ1γ2 -μ2 γ1) 2 =0 ,指出当γ1ε2 =γ2 ε1,μ1γ2 ≠μ2 γ1时两区域波导模为横磁模 ,γ1ε2 ≠γ1ε2 ,μ1γ2 =μ2 γ1为横电模 ,γ1ε2 =γ2 ε1,μ1γ2 =μ2 γ1为杂交模 .并讨论了截止条件和传播特性 .     

High energy impact techniques application for surface grain refinement in AZ91D magnesium alloy

A nanostructured surface layer was fabricated on magnesium alloy AZ91D by using the high-energy impact technique (HEIT). With the help of transmission electron microscope (TEM) and high-resolution transmission electron microscope (HRTEM), the microstructure features of the surface layer were systematically observed and characterized in different stages of microstructure evolution. The result revealed the mechanism of grain refinement and strain accommodation. The process of grain refinement, accompanied by an increase in strain in the surface layer, resulted from several processes. The onset of deformation twinning and the intersection with twins system are one of them. The operation of basal slip and pyramidal slip led to the formation of dislocation cells and low-angle dislocation boundaries. The successive subdivision of grains to a finer scale resulted in the formation of highly disoriented nanocrystalline grains. The mechanism of grain refinement was interpreted in terms of the structural subdivision of grains together with dynamic recrystallization. The minimum size of such refined grains was about 40 nm.     

Dislocations in β-alumina electrolyte material

β-alumina obtained from a number of sources and manufactured by different techniques has been examined in the electron microscope. Dislocations have been observed on the basal plane and the Burgers vector determined as \(b = a/3< 11\bar 20 > \) . The presence of this type of dislocation has been explained on the basis of the crystallographic structure ofβ-alumina. It is also predicted that the unit dislocation dissociates into two and four partials according to the energetically favourable reactions: $$\begin{gathered} \frac{a}{3}< 11\bar 20 > \to \frac{a}{6}< 11\bar 20 > + \frac{a}{6}< 11\bar 20 > \hfill \\ \frac{a}{3}< 11\bar 20 > \to \frac{a}{6}< 1\bar 100 > + \frac{a}{6}< 0\bar 110 > + \frac{a}{6}< 0\bar 110 > + \frac{a}{6}< 0\bar 110 > \hfill \\ \end{gathered} $$ . Experimental evidence has been obtained which shows the presence of dislocations separated into two and four partials inβ-alumina. Microscopic deformation has been shown to occur in thin crystals ofβ-alumina in the electron microscope, by the passage of large numbers of dislocations along basal slip planes.     

Isothermal transformation and decomposition ofβ 1 phase in a CuZnAl alloy

In the present paper, the crystallography of isothermal transformation and decomposition ofβ, phase have been studied by means of transmission electron microscopy and diffraction in the CuZnAl shape memory alloy. It has been proved that the bainite formed inβ ₁, matrix when the samples were transformed isothermally at moderate temperature. The crystallography of the isothermal bainitic transformation is identical to that of martensite in the same system. When the specimens were aged at moderate temperatures for longer time, the bainite and matrix decomposed to equilibrium phases. The decomposition process can be summarized as follows: $$\begin{gathered} bainite (9R) \to 9R + \alpha \left( {fcc} \right) \to \alpha + \beta \left( {bcc} \right) \hfill \\ matrix (B2) \to 2H + B2 \to \beta \left( {bcc} \right) \hfill \\ \end{gathered} $$ There are definite orientation relationships among these phases during the decomposition process and they are shown below: $$\begin{gathered} \left( {111} \right)_\alpha \parallel \left( {001} \right)_B ,\left[ {0\bar 11} \right]_\alpha \parallel \left[ {\bar 110} \right]_B \hfill \\ \left( {111} \right)_\alpha 5^ \circ away from \left( {110} \right)_\beta ,\left[ {0\bar 11} \right]_\alpha \parallel \left[ {1\bar 1\bar 1} \right]_\beta \hfill \\ \left( {110} \right)_M \parallel \left( {001} \right)_{2H} ,\left[ {001} \right]_M \parallel \left[ {010} \right]_{2H} \hfill \\ \end{gathered} $$ Thus, the crystallography of isothermal transformation and decomposition ofβ ₁ phase and the sequence of transitions have been revealed.     

Wet chemical etching of the (111)In and $$ \left( {\bar 1\bar 1\bar 1} \right) $$Sb planes of InSb substrates

This paper examines etching of the polar planes (111)In and $ \left( {\bar 1\bar 1\bar 1} \right) $ \left( {\bar 1\bar 1\bar 1} \right) Sb of InSb wafers for liquid phase epitaxy in various etchants after mechanical and chemomechanical polishing. We describe procedures for polishing wafers and removing residual abrasive particles from the surface of polished wafers. A tartaric-acid-based etchant is shown to ensure a mirror-smooth finish of the $ \left( {\bar 1\bar 1\bar 1} \right) $ \left( {\bar 1\bar 1\bar 1} \right) Sb surface, with no visible oxidation. Etching of the (111)In surface with a lactic-acid-based etchant produces planes inclined to the parent surface at an angle close to the misalignment angle between the surface and (111) plane.     

Fe-Ni基合金中次生η相的析出机理

针对奥氏体合金中次生η相与基体位向关系存在的不同看法，研究了铁镍基奥氏体合金大量次生η相的析出机理，结果表明，η相与基体之间有良好的共格关系：{001}η／／{111}γ，（110）γ／／（210）η．晶界η相首先在一般无规晶界γ＇相处通过不全位错滑移产生堆垛层错带的方式形核，之后通过原子控制长程扩散机制的台阶方式在基体中长大，进入晶界另一侧与之匹配差的晶粒中，晶界随之一起迁动．η相的析出伴随着附近区域γ＇相的溶解和消失．