颊(舌)侧(牙合)支托在活动义齿修复中的临床应用分析

目的:探讨活动义齿修复中颊舌侧支托临床应用的可行性。方法:选取我院在1999年至2000年71例活动义齿修复患者,在修复体中设计颊舌侧支托84个,对其临床效果评价。结果:本组病例中66例颊舌侧支托成功使用3年以上,5例失败。结论:在活动义齿修复中设计颊舌侧支托是可行的。     

可摘局部义齿加合垫修复治愈双颊粘膜病一例

可摘局部义齿不良修复导致颊粘膜疼痛,继发白色念珠菌感染,不恰当的义齿和基牙磨改使咬合垂直距离降低,引起颞颌关节功能紊乱,本文报告了一例通过重新制作可摘局部义齿,在上颌颊侧牙尖处增加斜度加大覆合覆盖关系,同时在基牙合面做合垫进行咬合重建,成功治愈颊粘膜病和颞颌关节疼痛的病例.     

戴活动义齿要防龋

笔者观察了在我科修复的90例活动义齿的患者，结果报告如下：年龄为17－65岁，戴牙时间为5个月－10余年。修复前，对所有牙齿进行过检查并对已发生的龋齿进行了治疗，在90人中，有285个牙齿分别与卡环、颌支托、固位体或义齿的邻接面相接触，对这些牙齿进行了检查。结果：285个牙齿中，发生龋齿、龋斑的共116个牙，占总数的40．7％。其中55个牙发生龋齿，占19．3％；61个牙发生龋斑，占21．4％。以下由三方面进行比较观察。1、戴义齿时间与龋齿发生的关系：由表1看出，戴义齿的时间越长，发生龋齿越多。2、患者夜间是否摘除义齿，与龋齿发生…     

10例磁性附着体在口腔修复中的临床应用体会

目的：探讨磁性附着体义齿应用于口腔修复的临床效果。方法：对来本院就诊的10例牙列缺损患者，利用口内余留牙或残根残冠，安置磁性附着体进行覆盖义齿修复，并对义齿的固位、咀嚼、修复体使用情况的满意度以及义齿应用后出现的问题随访观察3年。结果：10例患者18件磁性附着体中，两颗基牙出现龈炎，未发现继发龋、基牙松动、义齿折裂、根面板脱落，所有覆盖义齿固位效果满意。结论：磁性附着体义齿不仅改善了传统全口义齿和复杂可摘局部义齿固位欠佳、咀嚼效率偏低的情况，并且由于其具有美观舒适，不传递侧向力，保护基牙，患者取戴方便等优点，临床应用前景广阔。     

活动义齿与口腔龋齿

为了探讨活动义齿与口腔龋齿之间的关系，我们科室观察了60树活动义齿的患者，其结果报告如下：年龄为18－65岁，戴牙时间为半年—7年有余，镶复前，对所有的牙齿进行过检查、并对已经发生的龋齿进行了治疗。在60人中有190个牙齿分别与卡环、支托、固位体或义齿的邻面相接触、对这些牙齿进行了检查。结果190个牙齿中发生龋齿、龋斑的共78个占总数的41％，其中36个牙齿发生龋齿，占总数的18．9％。42个牙齿发生龋斑，占总数的22．1％。以下由二方面进行比较。1、戴义齿时间长短与龋齿发生的关系：由表1看出戴义齿的时间越长、发生的龋齿越多…     

髓腔壁缺损对下颌前磨牙髓腔固位冠修复应力的影响

采用三维有限元的方法,研究髓腔固位冠修复下颌第一前磨牙时,不同形态髓腔壁缺损对牙体组织和修复体所受应力的影响,为临床优化设计提供参考。通过Mimics、Geomagic、UG、Hypermesh软件建立5种髓腔壁缺损形态(A组为完整髓腔壁;B组为舌侧髓腔壁;C组为颊侧髓腔壁;D组为远中髓腔壁;E组为颊舌髓腔壁)的下颌第一前磨牙髓腔固位冠修复有限元模型。加载位置位于颊尖舌斜面中心区域,载荷大小100N,方向为与牙齿长轴成45°、平行于牙体长轴。采用Abaqus软件计算分析5种髓腔壁缺损形态行髓腔固位冠修复后牙体组织和修复体的应力分布情况、von Mises应力峰值、粘结层内的应力分布情况以及Tresca应力峰值。结果表明:45°加载条件下,修复体颈部、牙体组织以及粘结层内应力水平均远远高于平行牙体长轴加载的情况;45°加载时,C组牙体组织内等效应力峰值最小,B组牙体组织内等效应力峰值最大;髓腔壁缺损使粘结层内应力水平显著提高,尤其对于近/远中侧髓腔壁缺损的情况。颊侧髓腔壁在抵抗来自颚侧的侧向力时发挥重要作用。髓腔壁的缺损使粘结层内应力水平显著提高,在长期交变外力作用下,粘结层存在失效的可能性。     

三十三例牙根切除木临床观察

牙根切除术又名截根术或折根术是消除多根牙，深牙周袋的一种方法。自１９８５年以来，对３３例磨牙的牙根切除术进行临床观察，取得满意效果，报告如下：资料与方法：１．临床资料，３３例中男性２５例；女性８例，上颌磨牙１６例，下颌磨牙１７例，其中上颌近中颊根切除１２例，上颌远中颊根切除４例，下颌近中根切除８例，下颌远中根切除９例。２．方法：术前准备（１）患牙在龈上法治，龈下刮治，调颌，以消除炎症，消除创伤。（２）磨改牙冠外形，减小颊舌径降低患牙咬合负担。（３）严密充填需保留的牙根根管，并用细圆钻在拟断牙根根…     

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.     

磁性附着体义齿修复磨牙游离缺失临床效果观察

目的观察磁性附着体义齿修复游离缺失磨牙的临床效果。方法对10例单侧游离缺失磨牙和5例双侧游离缺失磨牙的患者先进行卡环式活动义齿修复,测定其固位力、咀嚼效率和体积,再进行磁性附着体义齿修复,测定固位力、咀嚼效率和体积,对前后两组数据进行比较分析。结果磁性附着体义齿修复游离缺失磨牙具有足够的固位力,比卡环式义齿咀嚼效率提高10％～20％,体积减少25％～40％。具有统计学意义。结论磁性附着体义齿修复游离缺失磨牙效果美观、舒适、咀嚼效能高,是一种较好的修复方法。     

百强固位纤维粘结桥在前牙种植临时修复的应用观察

目的探讨百强固位纤维复合树脂粘结桥在前牙种植临时修复的短期临床效果。方法对30例34颗牙分2类4组,15例种植后传统活动义齿临时修复,15例百强固位纤维粘结桥临时修复,6个月和12个月复查,全面评价使用效果并分析比较。结果 20例6个月后临床复查,10例12个月复查,粘结桥全部不松动、修复体完好,无折断、缺损或过度磨耗,无明显着色,固位体边缘与粘结剂界面临床观察结合良好,基牙的探诊出血指数(Bleeding Index,BI)、菌斑指数(Plaque Index,PI),综合评价得分与传统活动义齿比较差异均有显著性(P<0.01)。结论百强固位纤维粘结桥是一种非侵入的固定修复方法,各项指标均优于活动义齿,是个别前牙种植后极好的临时修复方式,应为临床上首选。     

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.     

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.     

A computer generator for randomly layered structures

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

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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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。     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to