基于B／S结构网上选课系统的构建

文章通过分析B／S三层分布式结构和ASP技术,叙述了网上选课系统的构建与实现方法,着重介绍了编写程序时的一些关键技术。本文利用ASP技术和ADO技术相结合,实现客户端与服务器端的数据交换,能快速地完成选课系统的各项任务。     

分布式PowerBuilder设计

随着Internet的不断发展和普及 ,传统的客户 /服务器二层应用模型已经不能满足计算机应用的扩大发行、维护和升级的要求 ,计算机应用向多层应用的发展已成为必然趋势 针对这种情况 ,笔者着重分析了PowerBuilder的分布式应用的体系结构、分布式应用中服务器端不可视对象及客户端组件的构成 阐述了分布式应用的实现原理 结合典型的三层应用模型 ,给出了用PowerBuilder进行分布式应用开发中 ,创建服务器应用和客户端应用的基本方法 提出了在开发过程中应注意的问题     

ADO.NET对象在数据库编程中的应用

ADO.NET是.NET Framework中不可缺少的一部分,它是一组类,通过这些类,我们编写.NET应用程序就可以访问数据库以及其他数据存储。文章介绍了ADO.NET的结构,探讨了ADO.NET对象在数据库编程中的应用,并给出了C#实现代码。     

基于Web的分布式多层数据管理系统的研究及实现

介绍了一种全新的分布式多层数据管理系统的结构和实现方法,并详细讨论了实现这样的系统结构可能面临的一些问题及解决措施。该结构以C/S结构为基础,把以往由客户端或数据库服务器端实现的企业应用逻辑提取出来封装成企业对象,并将其分布于应用服务器端。与传统的C/S结构相比较,该结构具有较高的可移植性、稳定性及数据安全性。     

分布式PowerBuilder设计

随着Ｉｎｔｅｒｎｅｔ的不断发展和普及，传统的客户／服务器二层模型已经不能满足计算机应用的扩大发行、维护和升级的要求，计算机应用向多层应用的发展已成为必然趋势。针对这种情况，笔者着重分析了ＰｏｗｅｒＢｕｉｌｄｅｒ的分布式应用的体系结构、分布式应用中服务器端不可视对象及客户端组件的构成。阐述了分布式应用的实现原理。结合典型的三层应用模型，给出了用ＰｏｗｅｒＢｕｉｌｄｅｒ进行分布式应用开发中，创建服务器     

基于面向对象技术的继承机制剖析

OO技术用类来描述具有相同特征的一组对象，以继承作为共享机制，支持单一继承和多重继承．在面向对象的程序设计中，多继承使用频繁，但容易出现二性义问题．继承机制提供了规范化的结构体系和具有自然意义的重用方法，实现了代码和对象域的共享，从而使应用程序更容易维护、更新和升级．     

基于ASP．net的服务器控件设计

ASP．NET服务器控件是在服务器上运行并封装用户界面及其他相关功能的组件。这些服务器控件在ASP．NET页和ASP．NET代码隐藏类中使用。其运行在服务器端，经过服务器端某些程序的解析再生成标准的HTML代码显示在我们的浏览器上。设计自定义服务器控件的意义：提高代码重用率，方便快速开发，以及程序升级维护。     

基于ADO．NET数据库访问技术的研究与实现

ADO．NET是基于．NET平台下的数据库访问技术，本文阐述了ADO．NET的功能、结构和对象模型．给出了基于C#．NET的ADO．NET技术访问数据库的具体实现过程，并给出了部分实现代码。     

无状态对象及应用

介绍了基于 MIDAS的多层分布式系统结构 ,分析了无状态对象和可重复使用远程数据模块的关键技术 ,给出了在客户端数据集与应用服务器端的数据代理间进行状态信息通信的方法 .     

在VFP中用类的概念设计通用数据库浏览工具

类和对象是现代面向程序设计方法学中的基础概念。类代表了一种事物的抽象 ,规定了事物的特性 ;对象由类派生而来 ,是具备类所规定的特性的一个实例 ;同一个类可以有多个对象。利用类和对象进行编程 ,可以简化程序设计各个部分之间错综复杂的联系 ,程序容易读懂 ,并且能通过重用代码而提高编程的效率。重用代码是通过类的机制而实现的 ,在本文中 ,我们将给出体现类的代码重用思想的一个具体例子 ,同时这个例子也具有相当的通用性 ,对于数据库程序设计有一定的借鉴作用。在 VF P中 ,类可以分成两种 :基类和派生类。基类是 VFP自身定义的基…     

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.     

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.     

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.     

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.     

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.     

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.