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1.
管网直埋敷设以其占地少、工程量小、施工快与热损失少等优点广泛应用到城市集中供热热网中。随着供热事业的发展,热用户不断增加,有的大城市一条热网的长度就达到几十公里,直埋管网分布于不同土壤条件的埋层中,在热网不断的延伸过程中,其发生事故的可能性增加了,可靠程度在降低,而人们对其的依赖程度却在不断增加,但直埋管网爆管事故的可能性在增加。本文通过对这一过程建立数学模型,对影响管网安全的可靠性的进行分析,提出相应的补救措施与建议。引起相关领域人员的重视,减少管网事故的发生,维护公共安全。  相似文献   

2.
针对吉林省肿瘤医院供热管网的现状,分析了存在的问题及产生原因。在满足区域内现有及新建建筑物供热需求并兼顾原热网敷设条件的基础之上,提出了热网改造方案,进行了设计。重点加强了热网的热力平衡和调节手段的设置。并通过系统热力平衡分析和加设调节装置等技术手段解决了水力失衡问题,达到较满意的效果,为供热管网进行热力平衡积累了一定的经验。  相似文献   

3.
论述了热网自动化控制系统方案、功能和特点以及管网调节原则,分析了系统的各种运行需求及其应用,提出了选型和运作的原则、原理.采用热网自动化系统,达到了节能增效目的.  相似文献   

4.
任高 《科技信息》2009,(18):269-269
为了调节热网平衡,在管网上增加调节和控制阀门,改变流速的变化,因此容易产生噪音。本文分析了管网噪音产生的原因及避免噪音产生的解决方法。  相似文献   

5.
为了调节热网平衡,在管网上增加调节和控制阀门,改变流速的变化,因此容易产生噪音。本文分析了管网噪音产生的原因及避免噪音产生的解决方法。  相似文献   

6.
本文针对目前热网管理中存在的问题,以热电二厂热力公司所属管网换热站为例提出了一种基于Web的热网监控系统概念,详细论述了系统的功能,软、硬件的实现方法以及通讯方式。  相似文献   

7.
集中供热是指以热水或蒸汽作为热媒,由一个或多个热源通过热网向城市、镇或其中某些区域热用户供应热能的方式。从施工过程质量管理与施工过程质量监督两方面,介绍了供热管网工程施工中质量监管的要点,以期对热力施工的发展有所启示。  相似文献   

8.
随着城市供热管网的不断扩大,如何科学有效地控制和管理热网,提高热网的经济和社会效益,成为供热企业急需解决的重要课题.文章介绍利用先进的微机监控系统和可靠的网络通信技术,对热力站的运行参数进行实时监测,并采用智能控制仪对热力站施行本地智能控制,以适应室外温度与热网运行状况的变化,从而有效地解决热网的控制和管理问题.  相似文献   

9.
论城市供热管网的优化设计   总被引:2,自引:0,他引:2  
供热管网的合理的布局是城市建设和发展的前提条件。本文首先对我国城市供热管网的特点与常用设计技术进行了探讨,指出在供热管网的设计和运行中,应从热网优化的具体要求出发。同时从7个方面来阐述如何搞好城市的供热管网优化设计问题。  相似文献   

10.
王玉峰 《科技资讯》2012,(32):82-83
旋转补偿器是一种新型无推力的管道补偿器,在城市供热管网工程的应用中具有极大的优越性和灵活性,本文简述旋转补偿器的工作原理和特点,并探讨在热网工程中布置的形式以及布置原则,通过工程实例阐述旋转补偿器在热网管道补偿中的应用,以及与其他热网补偿方式相比的优点。  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
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。  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

18.
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.  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
The non-orthogonal localized molecular orbital(NOLMO)is the most localized representation of electronic degrees of freedom.As such,NOLMOs are thus potentially the most efficient for linear scaling calculations of electronic structures for large systems.However,direct ab initio calculations with NOLMO have not been fully implemented and widely used,partly because of the slow convergence issue in the optimization of NOLMO.We devel-  相似文献   

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