PCM编码的ISP技术实现

在简述实现PCM(Pulse Code Modulation)逐次反馈编码方法的基础上,采用先进的ISP(In-System Programmable)技术现代电子设计平台和开发软件,以ispLSI1016E芯片为核心,辅以相应的外围电路,实现了PCM编码的硬件电路配置和功能仿真设计.     

一种基于SVPWM控制的永磁电机变频调速系统设计与实现

通过分析永磁电机变频调速系统的构成和运行原理,采用DSP作为主控单元实现数字处理和SVPWM的控制算法,用智能功率模块及其外围电路完成变频主电路的变频调速系统的设计,实现了系统的硬件电路和软件算法详细设计.实验结果表明该系统具有良好的动态和静态工作性能.     

一种航标监测系统的设计与实现

采用PIC单片机,设计实现了对航标当前电压、电流及灯质等状态参数的测量电路,提供了红外接口,输出航标当前状态数据.该系统具有外围电路少、功耗低、电路简单等优点.     

基于无线传感器网络的温度监测系统

介绍了一种基于无线传感器网络的温度监测系统,其节点以高档8位AVR单片机AT-mega128L为核心,结合外围传感器和无线收发模块nRF2401,实现了对温度的监测.系统采用ZigBee无线通信协议,功耗低、性能稳定.     

基于RK2808的平板电脑FM收音模块设计

针对FM收音是许多消费电子的必备功能以及平板电脑的技术发展趋势,基于RK2808平板电脑解决方案,设计实现了FM收音模块.该模块采用SCT-806芯片,设计了相应外围电路及设备的驱动程序;模块应用程序的设计则结合了多种设计模式框架和多线程技术.所实现的FM收音模块操作界面友好简单,实用性强,成本低.     

8098单片机在高精度随动控制系统中的应用

介绍了由8098单片机及其外围电路组成的随动控制系统,重点论述了在本系统中采用的实现转速高精度实时测量的原理、实现电路及其具体操作方法.和其它几种常用的测速方法相比较,该方法能在保证相同的控制精度的条件下,用较少投资的硬件来实施对转速的高精度实时测量.     

MIDI音乐发生器芯片的设计

基于EDA技术,以MaxplusⅡ为软件开发工具,采用VHDL语言,在Altera公司的大规模可编程逻辑器件(CPLD)上实现了MIDI音乐发生器芯片的设计.该芯片配上必要的外围电路,可以发出美妙的MIDI音乐.     

基于DSP的语音信号采集系统的设计

设计了一种基于16位定点DSP TMS320VC5410的语音信号采集系统,该系统应用了集ADC和DAC于一体的SIGMA-DELTA型单片模拟接口芯片TLC320AD50C,采用FIFO技术进行缓存,CPLD实现控制逻辑,EZ-USB外围接口器件实现串行通信.主要介绍了系统的硬件结构和软件编程思想及实现方法.经测试,对语音信号回放人耳感觉不到失真.     

六自由度鼠标USB的实现方案

介绍了六自由度鼠标USB的实现方案.该方案采用器件PDIUSBD12和AT89C55WD单片机构成USB外设与PC进行通讯.由于PDIUSBD12具有诸多优点,功能齐全,外围电路要求简单,因此该系统具有良好的性价比.该方案能实现六自由度鼠标与PC的通讯,对于航天技术和机器人控制技术所需的多维人机接口输入设备的进一步研究具有重要的理论意义和实用价值.     

基于无线通信的非接触式IC卡读卡器设计

给出一种用于考勤系统的非接触式IC卡读卡器的设计及实现方法.采用射频识别技术及无线通信技术,以STM8S103F3P单片机为控制核心,设计了MFRC531读卡模块和Si4432无线收发模块,并详细论述了硬件外围电路相关参数的计算方法及软件实现方法.所设计的读卡器具有可移动性强、安装简单和扩展性好等优点.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the