纳米晶WC-6Co复合粉的制备

采用W,C和Co粉为原料,经机械活化—反应热处理工艺制备纳米晶WC-6Co(质量分数)复合粉末。研究结果表明:机械活化可使混合粉末化学反应活性增大,扩散能力增强,体系能量增高;反应热处理阶段活化粉末的反应具有反应温度低,反应速度快的特点;在900℃热处理保温35 min制备出粒度为33.3 nm的纳米晶WC-6Co复合粉末。复合粉末晶粒粒度随热处理温度的升高和保温时间的延长而缓慢增大,所制得复合粉末的热稳定性较好。     

一种新型晶粒长大抑制剂对YG10硬质合金烧结行为的影响

研究了一种新型晶粒长大抑制剂对机械合金化制备的纳米晶WC-10Co复合粉末真空烧结行为的影响,探讨了其影响机理.研究结果表明:新型晶粒长大抑制剂有利于烧结致密化;在传统的过渡族元素碳化物基础上添加新型晶粒长大抑制剂,能明显提高复合抑制剂抑制晶粒长大效果,使WC晶粒在烧结过程中明显发生定向生长,抑制盘状WC晶粒的形成;含0.1%新型晶粒长大抑制剂的WC-10Co-0.8VC/Cr3C2纳米晶复合粉末压坯在1375℃烧结30 min后密度为14.48 g/cm3,WC晶粒尺寸为160 nm,显微硬度为2.150 GPa.     

用球磨法制取WC—Co纳米粉

研究了利用高能球磨法制备纳米WC－Co混合粉末的可能性,以及球磨时间和WC－Co纳米粉末粒度的关系。结果表明：随着球磨时间的延长,WC－Co纳米粉末的粒度逐渐变小,当球磨时间超过30h后获得了粒度为100nm以下的WC－Co纳米粉末。     

Al2O3/WC-10Co/ZrO2金属陶瓷的制备与性能

以WC-10Co纳米复合粉末、YSZ纳米粉末与Al2O3亚微粉末为原料,采用热压烧结制备了性能优良的Al2O3/WC-10Co/ZrO2金属陶瓷.分别在1380,1450和1500℃烧结温度下制备Al2O3/WC-10Co/ZrO2金属陶瓷,通过考察烧结体的断裂韧性、洛氏硬度、密度、磁滞回线和断口形貌,研究了烧结温度对WC-10Co纳米复合粉末、YSZ纳米陶瓷粉末与Al2O3亚微粉末的复合粉末烧结性能的影响.确定合理的Al2O3/WC-10Co/ZrO2金属陶瓷烧结温度为1450℃.结果表明,质量分数为50%的WC-10Co纳米复合粉末、10%的YSZ纳米陶瓷粉末与和40%的亚微Al2O3粉末的复合粉末经过48h的高能球磨后,再经过1450℃热压烧结,可以得到晶粒尺寸小于1μm的整体性能较好的亚微Al2O3/WC-10Co/ZrO2金属陶瓷,其相对密度为97.5%,断裂韧性为7.4468MPa·m1/2,硬度为HRA 94.0.     

热处理工艺对双相纳米复合磁体性能的影响

采用磁粉晶化制备纳米晶磁材的方法,研究了热处理工艺对纳米晶复合磁体磁性能的影响。结果表明,热处理温度和时间明显地影响纳米晶的形成及其磁性能,热处理温度为700℃时,纳米复合磁体可以获得较好的磁性能。该研究方法工艺简单,成本较低,具有一定的实用价值。     

纳米晶W-Ni-Fe复合粉末烧结过程中的致密化与显微组织演变

采用溶胶喷雾干燥-热还原法制备纳米晶93W-4.9Ni-2.1Fe复合粉末,利用高温热膨胀仪测定和研究纳米品复合粉末的烧结收缩动力学曲线特征,计算纳米晶W-Ni-Fe复合粉末的固相烧结激活能,并利用金相显微镜和扫描电镜分析致密化过程中显微组织的演变规律.研究结果表明:纳米晶W-Ni-Fe复合粉末的开始收缩和剧烈收缩温度分别为900℃和1 120℃,其最大的线收缩率达0.097 ％/℃;在1 200℃以下的固相烧结阶段,压坯便发生显著的致密化,其致密化程度可达98％以上,固相烧结的表观激活能为154.83 kJ/mol,比传统粉末烧结激活能大大降低;在固相烧结期间,W晶粒尺寸长大缓慢,在1 380℃以上液相烧结时W晶粒长大急剧加快.     

溶剂热法合成Bi2Te3低维纳米结构及其表征

以NaBiO3·2H2O和Te粉为反应物,聚乙烯吡咯烷酮(PVP K130)为形状调控剂,通过溶剂热法合成具有不同形状的Bi2Te3纳米低维结构.系统研究了反应溶剂、反应温度和时间对Bi2Te3纳米低维结构的形状有显著影响.研究结果表明,反应溶剂、反应温度和时间对Bi2Te3纳米低维结构的形状有显著影响.用聚乙烯吡咯烷酮(PVP K130)作形状调控剂,在乙二酵(EG)中于200℃下反应45小时,成功合成了Bi2Te3纳米方块.用X射线粉末衍射和透射显微镜技术对所制备纳米晶的成分、晶相、形状和尺寸进行了表征分析.     

NiAl(Co)金属间化合物纳米晶块体材料的制备及其性能

采用机械合金化方法获得NiAl(Co)纳米晶粉末,经过热压,成功地制备出NiAl(Co)块体纳米晶材料·其晶粒尺寸约在300～480nm,致密度可达到91%以上,室温压缩屈服强度达到1250～1400MPa,是铸态NiAl合金的31～35倍,室温塑性良好,有大约13%的压缩塑性·其中Ni50Al40Co10纳米晶块体材料压缩率可达30%,而无裂纹产生;Ni50Al45Co5,在980℃高温压缩至195%无裂纹产生,变形均匀·还发现含γ′相的NiAl(Co)的双相纳米晶块体材料压缩性能优于单相NiAl(Co)纳米晶块体材料     

溶胶-凝胶法制备钙钛矿型复合氧化物La1-xCaxCoO3纳米晶

采用溶胶—凝胶法合成了 La1-x Cax Co O3 (X=0 .1 ,0 .3 ,0 .5 ,0 .7)纳米晶 ,采用 TGA技术确定干凝胶焙烧温度 ;XRD技术证明所合成粉体为钙钛矿型复合氧化物 La1-x Cax Co O3 ,其粒径为 2 0 nm左右 .实验表明 ,脱水温度 70— 80℃左右 ,p H值小于 5时较合适 .同时也考察了柠檬酸用量对溶胶、凝胶形成的影响 .     

热处理对纳米TiO_2/SiO_2复合粒子微结构的影响

为了掌握热处理对纳米复合材料微结构的影响情况,采用溶胶-凝胶法制备了高比表面积及大孔容的纳米TiO2/SiO2复合粒子.利用热分析、XRD、FTIR和比表面积测试仪等仪器对不同热处理条件的纳米复合粒子进行了表征.结果发现,纳米复合粒子中TiO2的锐钛矿型和金红石型晶型转变温度分别由一般的350℃和600℃升高到660℃和770℃,晶粒度随热处理温度的升高和时间的延长而增大;同时,随着热处理温度的升高,复合粒子的比表面积逐渐减小,且微孔减少比例由小孔径微孔占多数逐渐转变为较大孔径微孔占多数.     

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.