静、动态载荷下牙种植体骨内段位移比较的三维有限元分析

目的:对牙种植体全冠修复的三维有限元模型进行静、动态加载,以比较两种载荷下种植体骨内段位移的差异.方法:在同一牙种植体全瓷冠修复的三维有限元模型上施加静态载荷和一个周期为0.875s的动态载荷,应用ANSYS软件比较种植体骨内段位移量与位移云图.结果:种植体骨内段位移在静、动态载荷下种植体颈部位移大,位移集中在颊舌侧并向根端减少,位移主方向沿作用力方向.最大位移量在静态舌斜向颊载荷(8.967 μm)＞静态颊斜向舌载荷(7.019 μm)＞静态垂直载荷(3.777 μm );在一个周期动态载荷时,舌斜向颊载荷阶段最大位移量(25.559 μm)＞颊斜向舌载荷阶段最大位移量(14.619 μm)＞垂直载荷阶段最大位移量(8.884 μm).结论:种植体骨内段位移量在静态与动态载荷下均有统计学差异,动态载荷时大于静态载荷,但其位移分布规律相似;一个周期动态载荷下,种植体骨内段最大位移量产生在舌斜向颊载荷阶段,卸载后种植体仍有位移.     

不同根管印模材料对铸造桩适合性的影响

目的:比较嵌体蜡、自凝塑料、琼脂和硅橡胶印模材料制取根管印模对铸造桩适合性的影响.方法:选择离体上颌中切牙40颗,制备根管根向聚合度6°的实验标本,然后随机分为4组,每组10颗,分别用嵌体蜡、自凝塑料、琼脂和硅橡胶印模材料制取根管印模,灌注模型,模拟临床方法制作铸造桩,用玻璃离子水门汀黏固后,选择每个标本的根颈1/3的中部、根中1/3的中部横向剖开,将横剖面置于扫描电镜下观察,每个横剖面观察4个位点,以黏固剂厚度为观察指标,测量记录,每组取其平均值,各组数据两两比较.结果:嵌体蜡组黏固剂平均厚度为(41.11±3.78)μm;自凝塑料黏固剂平均厚度为(46.01±3.66)μm;琼脂组的黏固剂平均厚度为(39.42±3.85)μm；硅橡胶组的黏固剂平均厚度为(28.03±2.73)μm;嵌体蜡组与琼脂组的适合性相近,无显著性差异(P＞0.05)；嵌体蜡与自凝塑料相比适合性有显著性差异(P＜0.05)；其他材料间适合性均有显著性差异(P＜0.01).结论:4种印模材料在黏固厚度上都在允许范围内,而硅橡胶组印模制作的铸造桩,适合性优于其他材料,值得在临床上推广应用.     

深圳市常见园林植物滞尘效应研究

以深圳市6种常见的园林植物为对象, 研究其单位面积滞尘量及其粒径组成特征, 探究植物叶片表面的微观形貌结构以及滞留颗粒物的组分和分布特征, 分析气象因子对植物滞尘的影响。结果表明: 1) 6种园林植物的单位叶面积滞尘量排序为黄金榕(0.74±0.21 g/m²)>鹅掌藤(0.42±0.26 g/m²)>对叶榕(0.24±0.26 g/m²)>龙船花(0.20±0.07 g/m²)>沿阶草(0.18±0.10 g/m²)>鸡蛋花(0.15±0.10 g/m²); 2) 6种园林植物滞尘以粒径α>10 μm的颗粒物为主, 质量占比为59.21%~88.92% (黄金榕除外), 鹅掌藤对α>10 μm 颗粒物的滞尘能力最强(0.34±0.20 g/m²), 黄金榕对3 μm<α<10 μm (0.51±0.15 g/m2)和 0.15 μm<α<3 μm (0.14±0.07 g/m2)颗粒物的滞留能力最强; 3) 6种园林植物叶表面的气孔、褶皱、沟槽、絮状凸起和绒毛等微观形貌有利于叶片对颗粒物的截留, 叶片滞留颗粒物的元素组成主要为O, Si和Al; 4) 6种园林植物叶表滞留的大颗粒物(α>10 μm)易受风速和温度的影响。研究结果对深圳市园林植物配置具有指导意义, 并可为通过植物滞尘效应改善空气质量提供一定的理论依据。     

抚触对窒息新生儿行为神经评分与摄乳量的影响

目的 :探讨抚触对窒息复苏术后新生儿行为神经评分和摄乳量的影响。方法 :对 2 6例窒息新生儿实施新生儿抚触 (17例有窒息史但未施行抚触的新生儿为对照组 ) ,于生后第 7、15和2 8d观察抚触对新生儿行为神经评分与 2 4h摄乳量的影响。结果 :抚触组的摄乳量在生后 7、15和 2 8d分别为 (36 8 0± 17 4 )、(46 5 2± 2 1 0 )和 (5 6 8 9 18 6 )mL ,与对照组比较 ,其摄乳量明显提高 ,从第 7d开始差异就具有显著性 (P <0 0 5 )。抚触组在生后 7、15和 2 8d的行为神经评分为(2 9 2± 1 6 )、(34 7 2 9)及 (38 2± 1 4 )分 ,与对照组相比 ,在第 15和 2 8d ,差异有显著性 (P <0 0 5 ,P <0 0 0 1)。结论 :婴儿抚触有利于窒息新生儿行为神经功能恢复和食欲增加     

高速公路煤矸石路基包边土厚度分析

为确定煤矸石路基包边土的合理厚度,通过分析煤矸石填筑路基成型过程,建立了具有包边土的煤矸石路基简化有限元模型,分析了不同包边土厚度对煤矸石路基包边土内竖向最大压应力及竖向最大剪应力的影响规律,研究了包边土厚度对煤矸石路基中心沉降量、煤矸石路基边缘沉降量、包边土边缘沉降以及包边土差异沉降、路基最大差异沉降的影响程度。结果表明:路基高度相同时,包边土内竖向最大压应力及竖向最大剪应力随包边土厚度增加而增大,当路基高度小于5m时,内力受包边土厚度影响相对较小;包边土厚度变化对煤矸石路基中心沉降量、煤矸石路基边缘沉降量及包边土边缘沉降量影响较小,对包边土差异沉降量影响较大,随着厚度增加,差异沉降逐渐增大,但差异沉降量均在1.5 cm以内。     

中间退火及轧制工艺对Al-Mg-Li合金塑性开裂及晶粒细化的影响

采用机械热处理法制各Al-Mg-Li合金细晶板材,研究预热温度、中间退火温度及转向轧制对板材塑性开裂及品粒细化的影响.结果表明:板材在低温(≤300℃)轧制时往往开裂,将轧制温度提高到400℃,可获得无开裂的板材,但经再结晶退火后的晶粒组织粗大,约为16μm;降低中间退火温度虽然可以明显提高晶粒细化程度,但退火后采用单向轧制,当形变量较大时,板材会出现开裂问题;中间退火后采用转向轧制,不但大形变量F板材轧制不开裂,而且细化晶粒及减小板材厚度方向层状分布的程度,再结晶后2个表面层的晶粒细小等轴,平均晶粒粒径为9.26 μm;中心层晶粒组织相对粗大略成扁平状,平均晶粒粒径为12.73 μm,约占板材总厚度的1/5.     

成人磨牙及双尖牙根管充填后行烤瓷全冠修复的必要性

探讨磨牙及双尖牙在根管治疗后行金属烤瓷全冠修复的必要性,笔者对根管治疗后未行金属烤瓷全冠修复,且出现临床并发症的患者进行了临床对比分析,及病因分析。磨牙及双尖牙在根管充填及银汞充填后及时行金属烤瓷全冠修复,可降低并发症的发生,且可长久的保留患牙于口腔,是一种相当有必要的修复手段。     

基于线结构光的复杂深孔内轮廓三维测量方法

为了对孔内轮廓参数进行快速高精度测量,建立了一种基于线结构光的复杂深孔内轮廓三维测量系统.介绍了系统构成及测量原理、数学模型建立以及孔内截面轮廓尺寸计算方法.提出形态学光条细线化与灰度重心法相结合提取亚像素光条中心线算法.应用该系统对直径φ130.0 mm的复杂孔内轮廓进行实验,测量长度70 mm时,阳线圆直径测量误差为±32 μm,阴线圆直径测量误差为±54 μm.      

预变形对AA2195铝锂合金析出及晶粒细化的影响

在细化晶粒的传统机械热处理工艺中的过时效前引入冷轧预变形,研究预变形对AA2195 铝锂合金过时效第二相粒子组态及最终再结晶组织的影响.结果表明:预变形明显降低了过时效第二相沿板材厚度方向分布的不均匀性,并大大减小长度为5～10 μm的棒状第二相,显著增加尺寸为0.8～2.0 μm的第二相,从而提高再结晶时的形核核心.与未采用预变形的板材相比,经60%预变形的板材经轧制和再结晶后表层的晶粒尺寸由未预变形的12.6 μm减小至9.26 μm,其纵横比由1.61减小至1.27;中心层晶粒尺寸由14.62 μm减小至11.27 μm,其纵横比由2.47减小至1.70.过时效前的轧制预变形明显细化并等轴化AA2195 铝锂合金的晶粒.     

石龙子rADVR突触结构的定量分析

用实物及计算机投影系统对石龙子前背侧室嵴嘴外侧区突触的电镜图像进行放大处理和统计分析,测量结果:突触前膜平均厚度为70.3×10-10m,后膜平均厚度为117.7×10-10m,突触间隙平均宽度为147×10-10m,突触界面曲率为:平均值±标准差=(1.123±0.389)×10-10m,突触活性带长度为:平均值±标准差=(3 514.93±982.75)×10-10m,空心小泡直径为:平均值±标准差=(477.3±38.45)×10-10m(n=58),实心小泡直径为:平均值±标准差=(892±55.83)×10-10m(n=28).     

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.     

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.     

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。     

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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