冲击电充计与灵敏电流计的特性分析与测定

用角析方法分析了测量微弱脉冲电量与微弱电流的冲击电流计与灵敏电流的工作状态，给出了运动特性曲线，揭示了状态参量的物理本质。计算与测定了临界冲击常数Ｋｂ与无阻尼状态下冲击常数ｋａ之间的关系。     

利用冲击电流计测量水磁导率的研究

介绍了利用冲击电流计测量磁介质磁导率的方法，重点介绍了利用冲击电流计测量水的相对磁导率，并且研究了水从－１５℃到１００℃的相对磁导率。     

对灵敏电流计特性研究实验的教学探索

灵敏电流计是一种磁电式电流计,它的灵敏度特别高,可以用来检测闭合回路中的微弱电流(10-6～10-10A)或微弱电压(10-3～10-6V)。利用其自己高灵敏度的特点,在光电流检测,平衡电桥,电位差计等实验中,被广泛使用,但是针对《灵敏电流计特性研究》实验过程中存在的疑难点,从灵敏电流计的结构特点出发,补充强调了电流计为什么比普通的电流计更加精确,它的优点主要体现在哪里,灵敏电流计的三个特性对完成整个实验的意义。从电路出发,说明如何控制线圈的运动状态。最后,为了让学生正确使用电流计,介绍灵敏电流计的分流器结构。     

灵敏电流计内阻和电流计常数的测量探讨

通过实验,用三种电路对灵敏电流计内阻和电流计常数进行测定,并作出了结果分析.     

冲击电流计特性研究

一些教科书在研究冲击电流计特性时,认为当通过冲击电流计的电量Q不变时,电量冲击灵敏度S_Q=φ_m/Q随阻尼度减小而增大,因此,测量中应以力求得到高的电量冲击灵敏度作为选择冲击电流计工作状态的原则.笔者认为这一论点值得商榷. 在实际测量中,例如测磁通变化量△ψ时,若按此原则,那么,应选欠阻尼状态,但这时偏转量减小,即测量灵敏度(磁通灵敏度)反而降低,在改变阻尼度寻求较大偏转量的过程中,不同阻尼度通过冲击电流计的电量Q值不同.对欠阻尼,因回路电阻增大,脉冲电流减小,通过的电量Q减少,冲掷角φ_m也减小.尽管此时电量冲击灵敏度(S_Q=φ_m/Q与Q无关与入有关)较高,但测量灵敏度(S_ψ=φ_m/△ψ)反而较低.因此不能以力求得到高的电量冲     

对《灵敏电流计特性研究》实验指导的探讨

针对《灵敏电流计特性研究》实验中存在的疑难点，从灵敏电流计的结构特点出发，补充强调了电流计与一般的指针磁电式电表的主要区别之一是其活动部分没有产生电磁阻尼矩的铝制框架，电磁阻尼矩只能由动圈和外电路闭合后产生；并补充说明了为什么对电流计机械调零时应使外电阻等于电流计的临界电阻．为了让学生正确使用电流计，介绍了电流计的分流器结构．最后强调说明了应使电流计工作在甚过阻尼状态下，才能精确测量其内阻．     

异步电动机专用电流计

针对异步电动机电流计存在的耐起动电流冲击和指示正常运行电流之间的矛盾，试制了一种新型的异步电动机专用电流计，经测试完全满足工程要求.     

冲击电流计特性研究的两种方法

由电磁测量中不同的前提条件,对闭路状态中冲击电流计的运动特性进行了两种不同方法的分析研究,从而提出其中一种对实际电磁测量有指导价值的结论．     

关于墙式冲击电流计的改进

<正> 冲击电流计是高等院校和科研单位物理实验室内,电磁测量方面必备的基本仪器。墙式冲击电流计是五十年代的产品,现在许多单位还有一定的数量。由于这种冲击电流计在结构上存在着一些问题,导致了对它的利用率较低。为了节省国家开支,使这批仪器发挥更多的作用,将这种冲击电流计作了一些改进,改进后的冲击电流计,经过两个学期的使用,证明     

待测电阻与标准电阻的阻值差异对冲击电流计测量电阻误差的影响

通过实验分析用冲击电流计测量电阻时误差与标准电阻与待测电阻阻值差异对冲击电流计测量电阻误差的影响，发现标准电阻与待测电阻阻值相差不大时，冲击电流计测量电阻误差就小，反之就大。     

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.     

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.     

A computer generator for randomly layered structures

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

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the