切削温度对刀具表面覆盖膜的影响

研究表明，用ＴｉＣ类硬质合金发具切削Ｃａ－Ｓ易切不锈钢时，刀具表面覆盖膜的形成及分布规律，与前刀面切削温度及其分布规律有关：切屑－覆盖膜间温度达到覆盖膜主要成分－钙黄长石的软化挤出温度９００℃左右和覆盖膜－前刀面间温度达到粘结温度８５０℃左右时，至主切削刃距离ｘ＝０．２－０．６ｍｍ范围便形成致密的稳定覆盖膜；ｘ＜０．１ｍｍ范围温度低于钙黄长石的挤出温度无膜生成：ｘ＞０．６ｍｍ温度稍低于钙黄长石的挤     

铠装热电偶测量刀—屑接触区切削温度分布方法

本文研究了用yTl5硬质合金刀具切削OCr16Ni10CaS有覆盖膜形成时刀具表面温度分布测量的实验方法。在线切割机床已普及的情况下,采用在硬质合金机夹刀片上开口插入热电偶测量切削温度分布的方法是简单易行的,所测的温度是可信的．同时也可用于其它工件材料的前刀面切削温度分布的测量。     

切削Ca-S易切不锈钢时刀具表面覆盖膜的研究(Ⅰ)

研究了切削 Ca-S复合易切不锈钢(0Cr16 Ni10CaS)时,刀具表面覆盖膜的形成,并在扫描电镜里对各种不同条件的覆盖膜进行观察和微区成分分析。实验表明:切削 Ca-S 复合易切不锈钢时,在较宽的范围内,前刀面均能形成覆盖膜;稳定形成覆盖膜的切削路程为 1 200—1 500 m;覆盖膜的成分以 CaO,Al_2O_3,SiO_2,MnO 和MnS为主,兼有少量被切削金属的元素(Fe,Cr,Ni);切削区的平均温度为 950—1 050℃时覆盖膜较厚,有效覆盖面积较大。     

切削Ca-S易切不锈钢时刀具表面覆盖膜的研究(Ⅱ)

研究了切削Ca-S易切不锈钢时,在覆盖膜生成的条件下,前后刀面的磨损特点、覆盖膜的厚度及影响因素。结果表明,前刀面有覆盖膜形成时,其磨损形式有两种:一种为平前面磨损;另一种为月牙洼磨损。覆盖膜对前刀面有明显保护作用。在实验条件下,前刀面覆盖膜厚度可达1.6～18μm,它随切削速度和进给量的增大而增厚。在后刀面的磨损带里,没有完整覆盖膜形成。只是在刀尖部分产生了很簿的覆盖膜。     

切屑与刀具前刀面摩擦系数的实验研究

研究金属切削过程中切屑和刀具前刀面之间的摩擦现象,找出其变化规律,对了解和控制金属切削刀具的磨损过程及磨损速度,以提高刀具耐用度,具有十分重要的意义。刀具前刀面上的切屑与刀面之间的摩擦条件,比一般机械磨损过程要严酷得多:首先,切屑与前刀面之间的压力很大(可达1.96～2.94GPa以上),加之摩擦速度高,会产生大量的切削热,形成很高的切削温度。因而,在距切削刃一定范围内,切屑底部的金属要和刀具前刀面产生粘结。在粘结区域内,切屑与刀具前刀面的摩擦就不再是一般的外摩擦,而是粘结部份和上层金属之间的相对滑移,即内摩擦过程。所以,切屑与     

用切削液超高压注入法提高刀具寿命的研究

将切削液用喷嘴从刀具的后刀面超高压注入，使喷流直接作用于刀头与工件的接触点上，经实验研究表明，工具的后刀面磨损、月牙洼磨损、刀头的温度与常规切削相比大幅度下降，且后刀面磨损形态亦与常规不同，刀具的寿命可延长３倍以上．     

高速铣削TC6钛合金的刀具磨损机理

通过物理气相沉积（PVD）和化学气相沉积（ CVD）涂层硬质合金刀具对α+β相钛合金TC6进行高速铣削加工,研究了PVD与CVD刀具在铣削TC6钛合金过程中的刀具磨损形态和磨损机理.结果表明：在相同的切削条件下,PVD涂层刀具后刀面磨损量更小,刀具寿命更长,更适合TC6钛合金的加工.其前刀面主要发生黏结磨损和氧化磨损,后刀面则为边界磨损,由于前刀面黏结磨损和后刀面边界磨损对切削刃的弱化作用,使得主切削刃发生了微崩刃.CVD涂层刀具寿命较短,其前刀面主要发生初期微崩刃和随之而来的月牙洼磨损以及黏结磨损;后刀面则为磨粒磨损,失效形式为涂层剥落.     

瞬时红外热成像检测刀具温度场

本文采用红外热成像技术检测了切削刀具温度分布,给出了多种工件材料、刀具材料及切削速度等条件下切削刀具的温度场;还研究了后刀面磨损量与刀具最高温度值及其分布特征之间的关系。试验表明:此技术可以快速、直观、非接触、较精确地在线实时无损监测切削温度,为选择最佳切削工艺参数、提高零件表面质量及刀具寿命提供依据。     

用切削液超高压注入法提高刀具寿命的研究

将切削液用喷嘴从刀具的后刀面超高压注入，使喷流直接作用用刀头与工件的接触点，经实验研究表明，工具的后刀面磨损，月牙洼磨损，刀头的温度与常规切削相比大幅度下降，且后刀面磨损形态料与常规不同，刀具的寿命了延长３倍以上。     

刀具前角对切削加工振动的影响（英文）

对机械加工中刀具前角对切削加工振动的影响进行了系统的实验研究和相应的理论分析,结果表明：随着刀具前角增加切削加工振动的振幅逐渐减小．当刀具前角γ０ ＜ ０°时,最大振幅产生在Ｖ＝ ５０～７０ｍ ／ｍ ｉｎ;而当γ０ ≥０°时,最大振幅产生在Ｖ＝ １６０～１８０ｍ ／ｍ ｉｎ．为精密和超精密加工中有效地抑制或避免切削振动提供了理论与实验依据     

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.     

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.     

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.