聚晶金刚石切削齿散热电阻钎焊工艺的研究

采用散热电阻钎焊工艺对聚晶金刚石切削齿进行钎焊，钎缝的抗剪强度达４１７．５ＭＰａ，复合片的磨耗比下降率小于１０％。采用表面测温实时监控技术，使复合片上金刚石层受热的温度低于７００℃用复合片切削岩石，由此测定出复合片的耐磨性，这样增加了测试结果的可靠性，现场应用表明，用本工艺钎焊的聚晶金刚石切削齿制造的钻头质量稳定，基本无掉片现象。     

以切代磨加工花岗岩的表面分析

本文介绍了用聚晶金刚石复合片刀具切削加工花岗岩以替代沿用的磨削加工的实验研究，比较分析了切削和磨削表面，说明以切代磨加工花岗岩是可行的．     

PDC钻头切削齿的受力模型的建立

PDC钻头(Polycrystalline Diamond Compact Bit,聚晶金刚石复合片钻头)以其机械钻速高,寿命长,综合效益显著等优点在石油钻井中有十分广阔的应用前景,其损坏的各种原因与钻进时其上切削齿的受力有关,本文建立了切削齿在钻进中的破岩受力模型,并进行了分析,得到了切削齿受力的影响因素,为PDC钻头合理的结构设计提供了依据。     

聚晶金刚石刀具的研究

聚晶金刚石刀具研究课题是机电部预研基金项目。1989年立题,1992年12月26日通过机电部鉴定。本课题在解决了聚晶金刚石复合片的加工技术的前提下,研制了加工硅铝合金、铜基粉末冶金等有色金属材料的切削刀具和加工石英玻璃、石墨电极、花岗岩、砂轮等非金属材料的切削刀具,为不少企业解决了生产难题,获得了很高的技术和经济效益。事实证明,聚晶金刚石刀具是一种用途很广、性能优越的刀具,有极广     

PDC钻头切削齿磨损分析

根据PDC钻头的工作原理及复合片性能特点,对PDC钻头复合片切削齿的崩齿、掉片、聚晶佥刚石层脱落、齿柱冲蚀四种磨损情况进行了分析,并从设计、制造、使用三方面提出了改进措施,为从事PDC钻头工作人员提供一些参考。     

一种PDC钻头布齿算法

本文讨论一种复合片金刚石钻头的布齿算法,该方法的依据是等切削原理,即在钻进过程中复合片金刚石钻头每个齿的切削量相等或近似相等,可望获得各齿均匀负荷、延长钻头寿命、提高钻井效率的目的。文中结合工程实际、分析计算精度、生成工程数据表,最后由计算机实现计算和绘制钻头布齿图,具有一定的工程实用意义。     

温度对Ni-Cr-P/金刚石烧结体组织和性能的影响

以金刚石和Ni-Cr-P预合金粉末作为磨料和合金钎料，采用钎焊工艺制备Ni-Cr-P/金刚石复合烧结体. 研究不同钎焊温度对Ni-Cr-P/金刚石烧结体的界面及磨削性能的影响. 利用差热分析仪（DTA）表征Ni-Cr-P合金的熔化特性，扫描电镜（SEM）观察Ni-Cr-P合金对金刚石的润湿效果及界面结构，XPS分析金刚石表面与合金的成键情况. 结果表明，钎焊温度为940 ℃时，金刚石表面部分碳元素向液态钎料中迁移形成Cr—C键，在金刚石表面生成一层致密的Cr3C2，有效改善了Ni-Cr-P合金对金刚石表面的润湿性. 940 ℃钎焊后金刚石单颗粒抗压强度为36.83 N，钎焊磨头的磨削比为64.2，相比于850 ℃钎焊时分别提高了18.27%和72.58%.     

钻头切削齿与胎体连接技术探讨

钻头切削齿与胎体的连接质量关系到钻头的使用寿命，因此有必要对切削齿与胎体的连接技术进行探讨。介绍了采用钎焊的方法进行连接；选择了相应的钎料与钎剂；并确定了工艺及措施。焊接后的钻头经实际使用表明，本连接技术保证了连接质量，是切实可行的。     

金刚石刀具切削铝合金时刀具材料和切削用量的选择

金刚石是切削有色金属的优选刀具材料。本文阐述了金刚石刀具材料的特性，切削加工铝合金时PCD刀具材料粒度和复合片厚度、几何角度、切削用量的选择。     

恒温时间对PCD复合片高频感应钎焊性能影响研究

采用AgZnCuMnNi钎料高频感应钎焊聚晶金刚石复合片(PDC)与硬质合金,研究了690℃钎焊温度下不同恒温时间对其钎焊性能的影响.利用扫描电镜、电子探针、X射线衍射仪等对钎缝界面和聚晶金刚石(PCD)层的热损伤进行了分析,并测试了钎缝抗剪强度.结果表明:钎缝内主要存在Ag基固溶体、Cu基固溶体、Cu0.64Zn0.36相和少量MnNi相,恒温时间15s时,含Cu基固溶体、Cu0.64Zn0.36相和MnNi相的灰黑色晶粒对钎缝起到弥散强化作用,钎缝抗剪强度达最大值350.6MPa;随着恒温时间的延长,灰黑色晶粒平均等积圆直径逐渐变大,钎缝边界形成连续金属间化合物层,抗剪强度下降;PCD层的热损伤随钎焊中恒温时间的延长而加剧,生产中应采用较短的恒温时间.     

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.     

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.     

The Analects and the Moment in Peking——The influence of a Confucian education system on the personality formation,the way of thinking and the fate of the main characters

0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation＇s behavior in their social life throughout the long history is beyond list.