一种可编程实时时钟芯片的设计

基于数字集成电路自顶向下的设计方法设计了一种新型的可编程高精度串行实时时钟芯片,可以输入不同的编程配置信息并精确计时.介绍了芯片的内部结构框图,给出了主要模块的设计方法.芯片采用I2C双线串行总线接口,具有计时、日历、报警、涓流充电等功能,可广泛应用于实际数字钟产品中.     

时钟芯片DS1302的原理及其Proteus仿真设计

本文详细介绍了实时时钟芯片DS1302的结构原理以及C51软件设计,同时给出了基于Pmteus用DS1302设计的串行LED显示的日历／时钟电路,说明了它的仿真方法。     

基于EP1C3T144的最小系统开发板的设计

提出一种新的FPGA最小系统开发板的设计思想,开发板以ALTERA公司的 Cyclone 系列的EP1C3T144为主芯片,配有I/O口、有源晶振、EP1C3T144芯片、电压转换芯片、两个配置接口（JTAG模式和AS模式）和AS串行配置芯片.开发板对I/O口的扩展作了进一步的改进,并以试验DDS为例,对该开发板的应用和功能进行验证.     

I~2C总线器件扩展单片机的接口

分析I2 C总线的优点 ,时序和数据传输格式 ,利用单片机的I/ 0口线模拟I2 C总线传输信息 ,以此来扩展单片机的I/ 0接口 .     

AT24C02在光纤陀螺测试中的应用

为保证光纤陀螺的工作精度,需要对光纤陀螺进行大量测试,为使测试过程方便、快捷,设计并实现了基于I2C总线的AT24C02的参数存储电路.PC机经过RS_232串口向光纤陀螺系统板发送参数,系统板通过DSP芯片对AT24C02进行读写操作.这不仅可以实时修改参数,而且掉电之后参数不丢失,加快了测试进程.     

电脑日历时钟及定时控制器

本文给出了在单片机的控制下ＭＣ１４６８１８日历时钟及控制器的一种使用方法，实现了掉电状态下的时钟运行，数据保存，和控制信息处理，体现了ＭＣ１４６８１８芯片在实时控制方面的优点。     

I2C总线控制技术及其在彩电中的应用

由于I2C总线控制技术因具有传送数据速率高、串行数据线和时钟线都是双向传输线等特点,以及很强的自动寻址、多微机时钟同步扣仲裁等功能,因此被广泛应用于彩色电视机中。     

长线422高速传输中的收发模块设计

为了实现长线422的串行高速传输,设计了以FPGA为控制芯片,DS26C31和DS26C32为差分线路驱动器的长线422收发模块电路;并给出了FPGA内部通过严格控制时钟实现高速串行发送、串行接收单元的逻辑设计。经测试,该设计能实现45 m双绞长线,速率达10.3 Mb/s的稳定可靠传输。     

基于2051的I/O口复用的定时控制器设计

本系统以AT89C2051单片机为核心部件,通过I2C总线与时钟芯片PCF8563进行通信,并将单片机的串行口与74HC164配合实现串口转并口输出,完成时间在四位一体LED数码管上的显示;为了节约I/O口资源,将独立式按键与数码管动态显示电路结合设计,使得按键具有时间设定和定时功能,从而通过继电器驱动接口电路实现定时控制。     

串行时钟芯片PCF8583在DSP系统中的应用设计

PCF8583是一款能精确到百分之一秒的时钟芯片,应用它能提高DSP的工作效率。本文用TMS320LF2407通用的双向I/O口模拟12C总线的时序。介绍了PCF8583和它与TMS320LF2407的接口及相应的硬件软件设计。     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

A computer generator for randomly layered structures

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

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.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

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.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to