激光加工中加工缺陷的研究

激光加工中加工缺陷的研究张桂华（天津市激光技术研究所３００１９２）在激光切割中，光束直径在切割中使加工工件产生误差。激光束经透镜聚焦后，其光斑直径约为０．１ｍｍ，切割后留有至少０．１ｍｍ的切缝，这就使得工件尺寸产生大于０．１ｍｍ的误差。为了解决这一缺...     

经尿道KTP激光治疗尿道狭窄12例分析

１　临床资料　　（１）一般资料：本组１２例，均为男性。年龄２０～６８岁，病程１～４年。狭窄位于膜部７例，球部３例，前列腺部２例。尿道狭窄段长１～３．５ｃｍ，１２例均经尿道造影证实。　　（２）仪器：采用美国斯柯普公司ＫＴＰ／ＹＡＧ双波长激光治疗系统。ＫＴＰ激光波长５３２ｎｍ，额定功率０５～３６Ｗ，工作方式可选择连续式或脉冲式输出。激光探头一种为可侧照射的非接触式探头，光纤直径为１８ｍｍ，提供的激光束与光纤轴呈７０°（±１０°）角；一种为直射的非接触性探头，光纤直径０６ｍｍ。另备常规膀胱镜及录…     

新型线列CCD热钢坯长度在线测量系统

提出一种新型线列ＣＣＤ热钢坯长度在线测量系统。该系统采用三块线列ＣＣＤ图像传感器，侧向斜视热钢坯，在有效视场内，对于钢坯±４００ｍｍ的中心偏移和±１５°以内的偏转角，能进行有效的测量，相对测长误差≤±０．６３％，采取适当措施，测量系统能在恶劣的现场条件下可靠地工作。     

生物热化学系统的微量热方法研究：Ⅰ.微热量计的研制

本文介绍了一种适于生物热化学研究，结构新颖的微热量计，阐述了热量计的设计原理，并对其结构进行了详细描述，热量计反应池容积为２５ｍＬ，检测灵敏度为０．１２ｍＷ，Ｌ＾－１测试精度≤±１％，恒温水溶控温精度为±０．００１Ｋ。用量热标准物质ＫＣｌ对仪器进行了标定，测得ＫＣｌ溶解热为１７５７１±２１Ｊ·ｍｏｌ＾－１，与文献值吻合。     

激光数字化采集和加工系统的精度分析

激光数字化采集和加工系统实验是在激光数字化采集和加工系统设计、安装、调试完成后进行的一些探索性实验.本文主要进行了激光数字化仪稳定性测量实验、重复精度测量实验和线性精度测量实验.实验表明,本系统可以测量采集倾角 ±75°的自由表面.激光数字化仪的稳定性精度为±0.0162mm,重复精度为±0.0351mm,在±1mm测量范围内的线性精度为±0.0770mm.在激光数字化采集时,数字激光化仪只工作在零点附近,因此,上述精度能够满足一般数控仿形加工中的精度要求.通过复杂曲面的采集实验结果,表明该激光数字化采集和加工系统原理正确,使用方便,跟踪稳定可靠,具有广阔的应用前景.     

多坐标系统参数传递法测量二维几何参数

通过辅助数控数显ＸＹ工作台与视觉系统结合，用多坐标系统间的几何尺寸参数传递关系解决测量精度与测量范围成反比的矛盾，使测量系统在１００ｍｍ×１００ｍｍ的范围内，测量精度达到０．０２ｍｍ（在Ｘ、Ｙ方向上），实现了０．０１％测量精度的要求．     

热电动势法快速测定微碳铬铁中硅含量

用热电动势法快速测定了微碳铬铁中硅含量．当冷热端温度差为２８０℃和黄铜为参比极时，热电动势Ｅ＿ｔ与待测极微碳铬铁中硅含量［％Ｓｉ］间有如下关系：Ｅ＿ｔ＝１４．２３８—０．５８２［％Ｓｉ］，ｍＶ．其测量精度与化学法和光谱法相比．分别为±０．０４％Ｓｉ和±０．０２８％Ｓｉ．每次测试时间为３０ｓ．     

电解珩齿试验及其原理探讨

本文作者预见，电解磨齿可能发展成一种高效率、高精度、工具寿命长的齿轮精加工工艺．试验结果证明．齿形精度可达０．０１ｍｍ，齿向凸肚修形可通过光电修形方便地达到，表面光洁度比机械珩齿略高。生产率以 ｍ＝３．２５．Ｚ＝３２，Ｂ＝４０，　＝２０°２７’淬火齿轮为例．机动时间约６分，公法线去除量为０．０６ｍｍ．本文着重从机理研究上提高精度特性。具体内容有：（１）电解珩齿中，电解珩磨纠正精度的机理及精度特性的提高途径：（２） 电解珩齿过程动力学分析；（３）机械活化中的啮合原理问题。     

注塑机料筒温度控制研究

以工控机作为数字控制器，采用非线性数字ＰＩＤ算法和脉宽调制（ＰＷＭ）原理，通过固态继电器（ＳＳＲ）来控制注塑机料筒温度，实现了料筒多变量加温系统解耦控制，使系统具有良好的动、静态性能，冷、热态工况温度控制精度分别达到±２．０℃和±．５℃．     

变断面零件轧制数控压下系统

通过采用数控压下系统和轧件尺寸在线检测系统的闭环控制,实现了变断面零件轧制成形的数控压下,并用典型模拟件进行了试轧·在使用直径３６０ｍｍ轧机轧制１０．０ｍｍ×２０．０ｍｍ矩形断面坯料时,轧件宽展偏差小于０．５ｍｍ·结果表明,该系统可以明显提高变断面零件轧制的尺寸精度·编制的智能化控制软件,便于人机交互,提高管理水平,对变断面零件直接轧制成形具有很大的实际意义和应用价值·     

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.     

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.     

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.     

Jane Eyre——A Feminist In The 19th Century

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.     

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-