干湿磨条件下氧化锆陶瓷表面粗糙度实验

目的研究干磨和湿磨两种工作条件下,金刚石砂轮磨削氧化锆陶瓷时,各磨削参数对其表面粗糙度的影响.方法通过在干/湿磨条件下对氧化锆陶瓷以不同的砂轮线速度、磨削深度、工件进给速度进行平面磨削,并观察磨削后工件表面粗糙度数值的变化,再利用电子扫描显微镜对磨削后的表面形貌进行分析.结果在湿磨过程中,当砂轮线速度为50 m/s、磨削深度为0.010 mm、工件进给速度为500 mm/min时,氧化锆陶瓷件表面粗糙度为0.191 8μm,表面质量最好;在干磨过程中,当砂轮的线速度为50 m/s、磨削深度为0.010 mm、工件进给速度为500 mm/min时,氧化锆陶瓷件表面粗糙度为0.189 5μm,表面质量最好.结论干湿磨条件下各磨削参数对氧化锆陶瓷表面粗糙度影响主次顺序分别为砂轮线速度、磨削深度、工件进给速度.同时在小磨削量的精密磨削中,干磨的表面粗糙度要优于湿磨的表面粗糙度.     

尺寸和球磨对细晶钨粉烧结体致密度的影响

采用溶胶喷雾干燥-煅烧-氢热还原法制备了粒径为0.14μm的超细纯钨粉末。研究不同球磨(干磨,湿磨)方式对钨粉形貌以及粉末成形性的影响,探讨纯钨样品性能随样品不同尺寸(2.5mm厚小样品和2cm厚大样品)的变化。此外还详细研究了纯钨烧结体组织形貌、晶粒尺寸等性能随球磨方式及样品尺寸的变化规律。结果表明,使用干磨法和湿磨法球磨处理都可以有效提高粉末的成形性。使用干磨法球磨制备的粉末的烧结体致密度高于湿磨法所制备的,且在大尺寸样品中其致密度分布也较湿磨法所制备粉末的烧结体更加均匀。湿磨粉颗粒粒径分布较广,颗粒容易长大。干磨粉由于活化效果较弱,烧结体颗粒更加细小。     

纯氧气氛下硬质合金及其原料的热稳定性

采用差热分析法研究了纯氧气氛下WC粉、Co粉、RE-Co预合金粉、WC-8Co硬质合金的热稳定性以及稀土对硬质合金热稳定性的影响.研究结果表明:费氏粒度分别为0.51μm和0.93μm的WC粉和Co粉分别在392℃和282℃就开始明显氧化,由于湿磨过程的活化作用与破碎作用,硬质合金混合料的热稳定性进一步降低,因此,在制备硬质合金混合料特别是超细硬质合金混合料的过程中对湿磨介质、混合料干燥方式与干燥温度等应进行严格选择与控制;在湿磨过程中,稀土以RE-Co预合金粉形式加入制备成含稀土的硬质合金,在混合料制备过程中RE-Co预合金粉不会发生明显氧化,其热稳定性与硬质合金基本原料WC粉和Co粉的热稳定性相当;稀土的添加量对WC-Co硬质合金的热稳定性影响不大,在合金中加入稀土不能使合金的明显氧化起始温度得到显著提高;在约700℃,WC-8Co硬质合金发生明显氧化,因此,WC-8Co硬质合金的实际使用温度应低于700℃.     

中速碗式磨煤机的结构工作原理及常见故障分析

一、碗式磨煤机主要由磨辊及磨碗装置、分离器部分、排出阀及多出口装置、蜗轮蜗杆减速箱等部分组成1、磨辊及磨碗装置磨辊和磨碗是磨煤机的碾磨部件,磨碗由主轴带动旋转,     

旋窑、立窑熟料混合磨制水泥颗粒分布与其性能的关系

实验测试了旋窑和立窑熟料经共同粉磨、分别粉磨后混合制得水泥的物理性能和颗粒分布。结果表明:将旋窑和立窑熟料共同粉磨,可改善水泥熟料的易磨性和颗粒级配,比表面积和强度均有所提高。关联度分析显示,各粒级对水泥3d和28d抗压强度影响的大小顺序是:<5,5～10,10～30,30～60和>60μm。统计回归分析结果也显示:强度发挥最好时,水泥中各级别的颗粒在总质量中的质量分数分别为:<5μm颗粒占0.180～0.200,5～10μm颗粒占0.090,10～30μm颗粒占0.350～0.370,30～60μm颗粒占0.220,>60μm颗粒约占0.150。验证了用n·X值来表征水泥中各级别颗粒分布的合理性。     

自动控制在MPS中速磨煤机中的应用

MPS是一种外加力型磨煤机,作为三辊磨煤机的一种,由磨盘带动磨辊进行作业,实现碾磨。物料经过落煤管进入磨盘,磨盘旋转过程中会产生离心力,将其输送到辊道上进行碾磨。碾磨力的产生来源主要是液压以及弹簧等加压装置。通过系统的三点,激昂碾磨力传导三个磨辊上,并且受力均匀,之后经加压系统将碾压力传导致基础。随着自动化概念在各行各业中的不断加深,自动化技术的研究也在不断的改进,传感器的研究以及开发成为了新型技术的研究就开发方向;现代研磨机控制中计算机的应用、网络技术的应用以及PLC技术的应用都在不断的深入,磨机的自动化已经成为了发展的逐流方向。     

聚合物硫铝酸盐水泥基材料的黏结性能

利用聚合物胶粉改性硫铝酸盐水泥的净浆和砂浆,通过测试拉伸黏结强度、抗折黏结强度和抗压强度,研究不同掺量聚合物胶粉对水泥基材料界面结合能力的影响。试验结果表明:在净浆中,当胶粉掺量为m(胶粉)∶m(水泥)=0.03时,28 d的拉伸黏结强度最大为3.26MPa;在砂浆中,当胶粉的掺量为m(胶粉)∶m(水泥)=0.009,水灰质量比在0.42时,14 d抗折黏结强度最大为7.0 MPa。     

高压辊磨对磁铁矿石磁选特性的影响

对弓长岭磁铁矿石的高压辊磨和颚式破碎产品分别进行阶段磨矿—阶段磁选—细筛再磨试验,分析了两种破碎方式对弓长岭磁铁矿石磨矿特性和磁选特性的影响。结果表明:高压辊磨工艺适宜的一段磨矿细度为-74μm含量占40%,颚式破碎工艺适宜的一段磨矿细度为-74μm含量占50%,两种破碎工艺适宜的二段磨矿细度均为-74μm含量占85%,最佳的细筛筛孔尺寸为50μm,三段磨矿细度为-45μm含量占80%。高压辊磨机碎磨分选工艺与颚式破碎机碎磨分选工艺相比,精矿品位相近,产率高0.52%,回收率高0.92%。     

磨矿介质对典型硅酸盐矿物浮选的影响及机理

研究在湿式磨矿条件下,十二胺和油酸钠作为捕收剂时,锆球和铁球作为磨矿介质对典型硅酸盐矿物浮选的影响。通过对矿物表面动电位和X射线光电子能谱检测,分析磨矿介质对硅酸盐矿物浮选影响的机理。研究表明：十二胺作为捕收剂,低于最佳浮选pH值时,锆球湿磨锆英石、绿柱石、锂辉石和石英的浮选回收率均高于铁球湿磨,pH值继续升高,锆球湿磨和铁球湿磨这四种硅酸盐矿物的浮选回收率相近；在pH值2~12范围内,锆球湿磨和铁球湿磨长石的浮选回收率相近；油酸钠作为捕收剂,相同pH值条件下,锆球湿磨锆英石、绿柱石、锂辉石、长石和石英的浮选回收率大多低于铁球湿磨。检测结果表明：锆球湿磨时,低于最佳浮选pH值条件下,锆英石、绿柱石、锂辉石和石英表面电位低于铁球湿磨,因而十二胺作为捕收剂时这四种矿物的浮选回收率高于铁球湿磨；铁球湿磨时,油酸钠作为捕收剂,锆英石、绿柱石、锂辉石、长石和石英表面Fe含量明显增加,对这五种矿物起到活化作用,因而浮选回收率高于锆球湿磨。     

高温快速直接碳化制取超细碳化钨粉末

采用由仲钨酸胺（APT）还原制取的蓝钨为原料，配碳并添加w=0.5％的VC，用高纯汽油作湿磨介质，在球磨筒中研磨36h后，采用自己设计的双筒圆舟作烧盘，在碳管炉中高温直接碳化，碳化温度为1400℃，保温时间为30min。采用上述条件成功制取了平均费氏粒度为0．3－0．5μm的WC粉末。此工艺方法比采用三氧化钨直接真空碳化的方法产量提高一倍以上，具有高效率、低成本的特点，适合大规模生产。     

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.     

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.     

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.     

A computer generator for randomly layered structures

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

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.