成型工艺对xPMS-(1-x)PZN陶瓷性能的影响

采用sol-gel方法预合成钙钛矿结构的PZT,采用固相法预合成MnSb2O6,然后用制得的PZT和MnSb2O6为原料,利用干压法和粉末电磁成型法成型,合成xPMnS-(1-x)PZN压电陶瓷,探讨了成型工艺对材料结构与性能的影响.结果表明粉末电磁压制法成型的样品致密度均达到了95%以上,性能均高于干压法制备的材料,当x=0.55时综合性能可达到最佳,分别为kp=0.46,Qm=391,tanδ=0.54%,ε3T3/ε0=1739,d33=347pC/N.     

烧结不锈钢丝网多孔板材的结构表征及冲击性能

以不锈钢丝网和不锈钢粉末为原材料,经过卷绕、压制、轧制和烧结工艺制造了烧结不锈钢丝网多孔板材.研究了不锈钢多孔板的孔隙结构特征和冲击力学性能,并进一步分析了孔隙率、原材料丝径及烧结参数对冲击性能的影响.结果表明:不含粉末的多孔板内的空隙呈规则的矩形,且孔隙尺寸分布均匀,孔隙尺寸分布范围较小;含有粉末的多孔板内的空隙形状复杂多变,孔隙尺寸分布范围较宽;多孔板的成型烧结温度越高,其冲击韧性越高;原材料丝径越粗,冲击韧性越好;材料孔隙率越低,冲击韧性越高;孔隙率对于冲击性能的影响最为显著,材料孔隙率从10. 64%上升到29. 18%时,不锈钢多孔板的冲击韧性从26. 32J/cm2下降到了8. 02 J/cm2.根据冲击试样断裂的宏观和微观形貌分析推断,材料在冲击载荷下经过了致密化、裂纹萌生、裂纹扩展、冶金结合点破坏、应力迅速上升后断裂几个过程,金属丝骨架断裂为典型的韧性断裂,在断裂时受到了轴向拉伸应力和垂直于断裂方向的剪切应力.     

高密度氧化铟锡(ITO)靶材的制备研究

 以水热合成的2种不同粒径(70±8)nm和(40±6)nm单分散ITO粉末为原料,对原料粉体粒径分布、冷等静压成型压力、烧结温度和时间等与靶材烧结密度之间的关系进行了研究.当2种粒径原料按7:3质量比混合均匀,成型压力为250MPa,成型坯体经1300℃预烧1.5h和在1400℃烧结1h后可以得到相对密度大于99%的高密度、高纯度ITO靶材.     

TiH2粉末制备钛合金的烧结脱氢规律及工艺

 以TiH₂粉末为原料,通过压制成型和烧结工艺制备粉末钛合金,不同于传统钛粉末冶金方法。通过热分析和热膨胀技术研究不同球磨粒度TiH₂粉末的脱氢和收缩规律,以此入手研究了TiH₂粉末压坯和TiH₂-Al-V粉末压坯的烧结致密特性,以及影响烧结过程的主要工艺因素,包括烧结温度、烧结时间、升温速率、压坯密度、压坯成型方式、合金体系,并对烧结组织进行了分析。结果表明,TiH₂粉末球磨后脱氢温度降低,粉末越细,开始温度越低。TiH₂粉末压坯在烧结过程中脱氢后获得新鲜钛,其易发生黏接并引起α-Ti的强烈收缩,这时烧结体很容易致密,并获得相对密度大于99%坯体;相比之下,TiH₂-Al-V粉末压坯烧结时因为合金元素的溶解,不如纯TiH₂粉末压坯的烧结容易致密。TiH₂-Al-V粉末经过成型、烧结脱氢可获得典型的层片状α+β钛合金组织,合金元素分布均匀。     

β-磷酸钙多孔生物陶瓷支架的制备及生物相容性

以制备高性能骨组织工程支架为目的,利用直接沉淀法合成β-磷酸钙(β-TCP)粉末,将粉末与Al2O3-MgO-H3PO4粘结剂按一定比例调和成浆料,采用有机泡沫浸渍法使其成型,低温烘干后,升温至900～1200℃烧结制得多孔β-TCP支架,通过体外细胞培养实验评价其生物相容性．研究表明,利用Al2O3-MgO-H3PO4作粘结剂,采用有机泡沫浸渍法制备的β-TCP支架孔隙率高,孔径大,具有开孔网状结构,而且无细胞毒性,生物相容性较好．     

莫来石晶须陶瓷膜的制备及其油水分离性能

以自制莫来石晶须为主要原料、硅溶胶为烧结助剂,采用浸渍工艺将硅溶胶附着在莫来石晶须表面,并用处理后的晶须通过干压成型制备莫来石晶须搭接的陶瓷膜。研究了硅溶胶浓度、成型压力和烧结温度对多孔陶瓷膜组分、孔径、孔隙率和渗透通量的影响。结果表明,使用质量分数5%的硅溶胶处理后的莫来石晶须在76 MPa压力下成型、1 400℃烧结得到的陶瓷膜孔隙率为54.7%,平均孔径为0.43μm。采用低温氧化法在膜表面生长纳米氧化钛进行改性,改性后陶瓷膜的油水分离通量为2 746 L·m^-2·h^-1·MPa^-1,截油率达到98.31%。     

0-3型PZT/PVDF压电复合材料压电性能研究

以PZT和PVDF为原料,采用热压和冷压两种工艺制备了0-3型压电复合材料,其中PZT陶瓷粉末由sol-gel法制得。研究了不同因素对复合材料压电和介电性能的影响。实验结果表明在相同成型压力下,PZT体积含量为70%时,热压和冷压工艺制备的复合材料d33分别为41和24,相差达到17,而ε相差最大值达到32.4。     

NiFe2O4合成工艺对惰性阳极力学性能及电导率的影响

研究以NiO和Fe2O3为主要原料合成镍铁尖晶石反应烧结过程中的热力学条件·同时对在不同烧结条件下合成的尖晶石二次烧结制备的阳极试样的抗弯强度及高温电导率进行了测量·结果表明:NiO和Fe2O3固相反应的热力学条件具备,反应先于致密化过程结束·当未经压制成型的粉料直接在合成温度为900℃下合成6h,经破碎工艺及二次烧结后,所制得的惰性阳极试样强度及电导率最大,烧结性能最好·而破碎工艺对增加粉末活性,提高试样电导率及力学性能也十分重要·     

铜与锰金属粉末的烧结特性

提出了用粉末冶金法制备铜锰固溶体的方法 ,研究了铜锰粉末压坯的烧结特性。结果表明 ,利用粉末冶金法烧结铜锰混合粉末 ,可以形成单相固溶体 ,其扩散机理属于单向扩散 ,即锰进入了铜。随着烧结温度的提高和保温时间的延长 ,铜锰烧结压坯的密度和硬度都有下降的趋势。铜锰粉末经混料、预压、热压成型后 ,按不同烧结参数 (包括烧结温度和保温时间 )在 80 0℃烧结 ,保温 5 0h ,可制得铜锰固溶体。     

PEG在溶胶-凝胶法制备PZT纳米粉末中的作用

采用硝酸氧锆、硝酸铅和钛酸丁酯为反应前驱物,水为主要溶剂,聚乙二醇和硝酸作为稳定剂和抑制剂,制备了稳定的PZT溶胶和单一钙钛矿相PZT95／5纳米粉末,并通过DTA／TGA、XRD、TEM等方法对纳米粉末的结构进行了表征,粉末平均粒径为65nm．结果表明：PEG的添加能有效地避免组分偏析,以无机盐为主要原料、水为溶剂制备PZT是可行的,且工艺简单、成本低．     

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.     

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.     

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.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

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.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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