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1.
提出了一种霍尔效应法测量螺线管轴线磁感应强度的实验装置。该实验装置采用直线电机带动霍尔元件在螺线管中移动,定位准确方便。螺线管励磁电流及霍尔元件驱动电流采用数控恒流源来提供,可以方便地改变方向及大小,精确控制测量时间,避免螺线管发热,从而提高实验精度,保护实验装置。  相似文献   

2.
研制了一种三维激光球杆装置,能方便地测量机床主轴或刀具的空间运行位置,介绍了装置的组成,误差分析和精度较正过程,该装置用于并联机床主轴空间运动位置的测量,实验和测量结果表明具有较高的测量精度和广泛的应用前景。  相似文献   

3.
阐述作者设计的定温汽液平衡实验装置的构造、性能及调试方法,并利用微机实现了实验装置的控制、参数测量和数据整理。装置的最高实验压力30MPa,测压精度0.05%,最高恒温300℃,恒温精度±0.01℃。还给出装置的控温精度、压力和温度偏差曲线。  相似文献   

4.
自制温度数据采集电路,以LabVIEW为虚拟仪器开发平台,设计并实现用于热学实验的数据采集与处理系统。实现实时显示温度变化曲线,自动处理实验数据并给出结果。应用结果表明:系统操作简单,界面友好。与传统测试方法相比,提高了测量精度和实验成功率,减小了数据处理难度。  相似文献   

5.
设计了一种简单的实验装置,可同时测量分子间相互作用的势能和普适气体常量R。其实验曲线符合理论值,误差分析后的补偿曲线所得结果可较为精确地与理论结果吻合。该实验常温下即可进行,且精度较高。该装置可用于课堂教学,有利于学生对热学问题的深入理解。  相似文献   

6.
介绍一种测量高温液态金属粘度的新的实验方法。根据泊肃叶定律进行理论推导,使用带自动控制系统的高频加热炉,用热电耦作温度传感器,用电子秤测量出经小孔流出的随时间变化的累积质量。使用微型计算机和数据采集系统连续记录这些变量,软件系统自动处理数据并计算出粘度值。方便的工业适用性、宽阔的温度范围以及快速数据处理是这个系统的主要特点。  相似文献   

7.
刘宗佳 《科技资讯》2012,(33):119-119
本文提出的温度采集控制系统以单片机(AT89S52)为核心,由控制部分、显示部分和温度测量部分组成。这套温度控制系统可以方便地实现温度测量、温度显示等功能,并通过与单片机连接的键盘可以实时设定测控温度的下限,还可以连接相应的外围电路,在收到单片机发出的指令后对环境进行加热。  相似文献   

8.
基于Lab VIEW软件,结合自主研发的圆盘式电流变传动机构,构建一个高性价比的虚拟仪器远程测试平台,方便地测量圆盘式电流变传动机构的响应时间、分析系统动态性能,进行伺服控制实验.在实验装置的主动盘和中间盘之间加以适当的电场,可以在输入轴转速变化的情况下,使小的输入力矩Msi克服大的负载力矩Mso,实现输出角度跟踪输入角度.  相似文献   

9.
金属线胀系数的测量是大学物理实验中一个重要的实验项目,提出一种新的结合迈克尔逊干涉仪测量金属线胀系数的新方法。利用迈克尔逊干涉仪可以测量微小长度的特点,测定金属在环境温度变化时细微的伸长量,通过高速摄像机记录干涉条纹变化的个数,并且利用常用的视频编辑软件premiere对干涉条纹的变化进行了数字化的处理,避免了迈克尔逊干涉仪同心圆形环条纹数变化太快而引起的测量误差,大幅度提高了测量精度,是光学和热学实验的有机的结合。  相似文献   

10.
远程温度监控系统的设计   总被引:3,自引:2,他引:3  
本系统是以AT89S51系列单片机为控制单元,并采用Dallas单线数字温度传感器DS18820采集现场温度数据而设计的远程温度控制系统.该系统具有结构新颖、电路简单和控制方便等优点,其监控的温度范围为-55℃~99℃,温度值显示的精度为0.01,并可根据需要设置控制温度的上、下限,系统具有超过设置上、下限温度自动报警等功能.系统可以被广泛地用于生产中的各领域,特别适合于人体无法接近的高温或危险场所的温度控制.  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.
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   

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.
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   

16.
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   

17.
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   

18.
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   

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.
1 Rise of studies on climate change's effects on biodiversity
Until the 1980s, climate change and biodiversity were studied as two independent disciplines for more than a century. In 1992, the Ecological Society of America's annual report named climate change, biodiversity, and the sustainable ecological system as the three major global environmental issues of the twenty-first century [1].  相似文献   

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