不同生物玻璃添加量对多孔HA陶瓷微观形貌的影响

采用聚氨酯泡沫浸渍法,在HA粉体中添加17.92CaO-56.8P2O5-17.00Na2O-6.28MgO-K2O-CaF2(质量百分比)生物玻璃作为助烧剂制备多孔HA.研究了不同玻璃添加量对多孔HA生物陶瓷微观形貌的影响.利用TG-DSC曲线分析制定烧结制度,采用扫描电镜观察多孔陶瓷表面形貌.试验表明:生物玻璃添加量为4wt%时,液相烧结作用显著,促进了晶粒的致密化,且晶粒尺寸分布均匀,利于强度和韧性的提高.此法制备的多孔HA具有均匀的开孔结构,孔隙相互贯通,孔径分布范围200-400μm,气孔率高达70-80%,作为组织工程支架材料具有很好的应用前景.     

多功能泡沫Ti-Al金属间化合物材料的制备工艺研究

在粉末烧结的基础上利用化学反应造孔和物理占位造孔这两种成孔机制,制备出新型多功能Ti-Al金属间化合物多孔材料。新型Ti-Al多孔材料含有微观孔(孔径尺寸微米量级)和宏观孔(孔径尺寸毫米量级)两种类型孔,具有良好的通孔性。     

氧化铝多孔陶瓷凝胶注模成型研究

以TH-903为分散剂,刚玉粉体为基体材料,以碳粉为造孔剂,采用凝胶注模成型方法制备了多孔氧化铝陶瓷.研究了分散剂、球磨时间和固相含量对浆料粘度的影响以及造孔剂含量对多孔陶瓷性能的影响.结果表明:加入质量分数为2.5%的分散剂可制得低粘度、高固相含量的陶瓷浆料.成型后的坯体经1360℃烧结1h,可获得孔径分布均匀、高显气孔率及强度较高的产品.     

真空烧结温度对多孔钛影响的研究

以碳酸氢铵做造孔剂,采用真空烧结法制备出生物多孔钛.研究了烧结温度对多孔钛显微形貌、显气孔率、抗压强度的影响.研究表明,提高烧结温度,有利于Ti晶体的发育,并提高制品抗压强度.     

无模板法制备三维互联大孔羟基磷灰石

介绍了一种新型的聚乙烯醇凝胶辅助法(PAF)来制备三维互联大孔羟基磷灰石(HA)陶瓷,PAF法不涉及模板剂、造孔剂的使用及复杂化学过程.X射线衍射分析表明:经烧结后的HA组分单一,为纯HA.扫描电子显微镜(SEM)和激光共聚焦显微镜观察结果表明:大孔HA孔结构的联通性和孔径大小可通过控制HA粉及PVA的用量来实现;当PVA与HA质量比为4.4和4.9时制得的大孔HA孔径分布较均匀,所制得大孔HA具有三维互联结构,大孔直径介于90~200μm,较接近人骨的孔尺寸和联通特性,具有潜在的应用价值.     

粉煤灰基多孔陶瓷过滤材料的制备和性能

以粉煤灰为骨料,采用添加造孔剂法制备粉煤灰基多孔陶瓷过滤材料,研究了造孔剂用量和烧结温度对其性能的影响.通过压汞仪、X射线衍射仪和场发射扫描电子显微镜等分析测试技术对试样进行了性能表征.结果表明:随着造孔剂用量的增加,显气孔率和吸水率升高,抗弯强度和密度下降.提高烧结温度可以有效提高抗弯强度,而不影响材料的主要物相组成;当烧结温度大于1 175℃时,显气孔率和透气度显著下降.造孔剂用量为35%,烧结温度为1 175℃时,可制得抗弯强度大、气孔发达及高比表面积的多孔陶瓷过滤材料.     

二氧化钛基多孔陶瓷材料的制备

采用粒径较小(30 nm)的TiO2为陶瓷骨架材料,且以聚苯乙烯(PS)和碳纤维为造孔剂,通过挤出成型的方法成功制备了TiO2基多孔陶瓷材料.由于PS粒径的单一性(3μm)和碳纤维尺寸的方向性,最后得到的烧结体既有单方向排列的条形孔结构又有孔径均一、分布均匀的圆孔结构.研究结果表明,烧结体的气孔率和弯曲强度与烧结温度、造孔剂种类及含量有密切的关系.     

多孔Ti-45Nb合金的微观组织与力学性能研究

新型多孔Ti-Nb合金因为具有良好的生物相容性,在硬组织植入材料领域中受到关注。本文利用纯Ti和Nb粉采用粉末烧结法制备多孔Ti-45Nb合金。通过造孔剂NH4HCO3调控多孔钛合金的孔隙度、孔隙尺寸、孔隙形貌、弹性模量和抗压强度。研究结果表明:随着造孔剂含量的增加,多孔Ti-45Nb合金的孔隙度和孔隙尺寸增大,孔隙连通性增加;弹性模量和抗压强度减小。多孔Ti-45Nb合金的孔隙特性和力学性能满足硬组织植入材料的基本要求。     

溶剂浇铸-粒子沥滤法制备PBS/PCL组织工程支架

选用聚丁二酸丁二醇酯(PBS)/聚ε-已内酯(PCL)共混材料作为组织工程支架材料基质,氯化钠和葡萄糖颗粒作为致孔剂,在传统的溶刺浇铸-粒子沥滤法的基础上,通过调节PBS/PCL的质量分数制得了不同尺寸且孔径、孔隙率满足组织工程支架要求的PBS/PCL多孔支架.对多孔支架的微结构、孔径、孔形态和素水性进行了表征,研究了PBS/PCL的质量分数、致孔剂粒径对支架成型及孔隙率的影响.结果表明,PBS/PCL的质量分教对支架成型影响较大,过低或过高的质量分数都会导致支架成型性差,质量分数在6%～10%时支架成型较好.利用质量分数为8%的PBS/PCL溶液可以制备形状复杂的多孔支架.所制支架内部孔洞分布均匀,贯通性好,孔径可由致孔剂的粒径来调控,支架孔隙率为86%～93%.支架亲水性良好,吸水率随孔隙率的增大而上升.     

炭粉作造孔剂制备工艺对多孔羟基磷灰石陶瓷性能的影响

以炭粉作造孔剂,制备了孔径在50 nm～ 1mm的多孔羟基磷灰石陶瓷.运用TG-DTA、SEM等测试手段对产品的微观形貌、力学性能进行了测试分析,并对烧结温度、炭粉加入量等这些影响陶瓷性能的工艺参数进行了研究.     

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.     

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.     

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.     

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.     

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with