基于开关电容的10阶Butterworth滤波器的设计和仿真

用开关电容电路在模拟集成电路的设计中取代电阻,具有电路规模小、功耗低、工艺过程比较简单、易于大规模集成等优势,本文应用开关电容电路技术对10阶Butterworth滤波器进行变换和简化,计算机模拟说明,其结果与理论计算值相符,更利于集成.     

开关电容微分电路

<正> 以MOS大规模集成电路技术为其实现基础的开关电容电路,近些年来以其特有的优点,受到了人们的重视。其理论分析和实际应用得到了迅速的发展。由开关电容电路组成的积分器,由积分器构成的各种滤波电路及积分加法电路等都已成熟。但至今还没有见到由开关电容电路构成的微分电路。本文通过适当安排开关电容支路,得到了一个开关电容微分电路。它将给开关电容电路的综合带来极大的方便。     

一种可编码的开关网络及其在自动测量中的应用

在对集成模拟开关及其主要电气性能讨论的基础上提出了一种可编码开关网络电路，分析了电路的工作原理及其简单实用等优点，并给出在接地电阻自动测量中的应用实例。     

一种用于图像处理的二维开关电容滤波器新的设计系统

二维实时滤波器开关电容网络新的设计方法．该设计是在综合法的基础上，利用无损、非倒数原形电路而得到的开关电容网络．本文所使用的几个计算机软件，可将其集成为一个完整的设计系统．本文作为该设计系统的应用，该滤波器可以象一个ＣＭＯＳ单片那样实现，若与数字滤波器实现相比较，可达到降低成本和减少功耗的目的．     

无电容R有源滤波电路

利用实际集成运算放大器的频率特性，给出了仅由电阻Ｒ和运算放大器组成的无电容Ｒ有源滤波电路及其理论分析，并就Ｒ有源滤波电路参数对滤波特性和电路工作的稳定性影响作了详细讨论，给出了Ｒ有源滤波电路参数的取值条件。     

利用模拟电感改进Chua电路的研究

首先介绍了Chua电路及其特性，给出实现非线性电阻的一种电路；然后设计了一种用集成运放、线性电阻和电容组成的模拟电感电路，利用模拟电感对Chua电路进行改进，取得了良好的效果；并且利用改进后的Chua电路构成的驱动一响应式混沌同步系统具有一定的鲁棒性、抗干扰等特性，为混沌在保密通信的实际应用奠定了基础。     

基于DDCC的互感耦合电路的有源模拟

 通过对互感耦合电路端口电压和电流关系的分析,提出了一种新的互感耦合电路有源模拟方法,并采用DDCC为有源器件实现了具体电路.提出的电路具有以下优点:① 控制不同开关组合可以实现正、负耦合电路;② 初、次级电感及互感可以通过调节外接电阻实现独立可调;③ 电路结构简单,仅由4个 DDCC器件,6个电阻和2个电容组成;④ 所有器件均接地,便于集成.将该电路应用到双调谐回路并进行PSPICE仿真分析,结果验证了该电路的正确性.     

超大时间常数开关电容积分器设计

结合T型开关电容积分器和Nagaraj开关电容积分器,设计出了新的超大时间数(VLTC)开关电容积分器的电路结构,可以将等效电容比率分解成三项比例乘积的形式,从而提高开关电容电路的面积效率.结构对运放性要求不高,易于超大时间常数积分器的全集成.     

一种简便实用的电容降压方法

目前，许多小型家用电器均采用电容降压法来获得供电电源，如超声遥控开关、电子节能灯等，它们的电源电路均是电容降压整流电路，电容降压法虽然具有一定的局限性，但却有很大的实际应用价值，通过电容降压法的原理，分析了电容降压法的适用范围，并给出一种选取降压电容的实用简便方法，利用该方法，可以根据具体线路的要求，快速，准确地确定出所需要的降压电容。     

改进型零转换单相PFC整流电路研究

原有的无辅助开关的软开关单相功率因数校正电路环流能量大。本文通过改变谐振电容Cr取值的大小，减小了环流能量。分析了电流断续状态下的工作原理，所有开关器件都可实现ZVT或ZCT软开关。并详细介绍了单周期控制原理。仿真和实验结果表明，该电路降低了功率管VM1和VM2的通态损耗，并提高了整体电路的效率。     

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.