Steffee槽式钢板治疗腰椎滑脱症

采用Ｓｔｅｆｆｅｅ槽式钢板治疗腰椎滑脱症共１２例，收到良好效果。滑脱度数在２５％～５５％之间，复位率９７％。手术要点：真性滑脱椎弓根钉进钉点靠横突，峡部裂要彻底切新，采用大块植骨．双侧同时复位。一般情况不切除椎板。因复位后可恢复脊柱的三柱结构，临床症状得以解除．骨质疏松是禁忌症。我们认为该钢板具有复位满意，固定可靠，促进融合等优点，是目前治疗腰椎滑脱症较为理想的方法。

Steffee钢板内固定治疗胸腰椎骨折

本文报告采用Steffee钢板内固定手术治疗胸腰椎骨折108例。术前平均椎体前、后高度分别是48.3%和75.6%,术后平均椎体前、后高度分别是86.8%和88.1%。术前Cobb’s角平均20.6°,术后平均6°。作者认为Steffee钢板系统结构简单,操作方便,固定坚固,但对有骨折块突人椎管内的爆裂型骨折,骨折块不能复位,椎体后高度恢复较差,建议对此类患者使用RF系统固定。

Steffee钢板内固定手术治疗腰椎滑脱

目的探讨Ｓｔｅｆｅｅ钢板内固定手术治疗腰椎滑脱的疗效。方法采用椎管减压、Ｓｔｅｆｅｅ钢板复位内固定、横突间植骨融合术治疗腰椎滑脱６１例。结果２６例得到完全复位，３５例部分复位，无手术并发症。术后随访５２例，随访时间平均２．８年，优良率为９０．４％。结论Ｓｔｅｆｅｅ钢板拉力大，能使滑脱椎体复位，同时有利于椎管探查及扩大减压，并且固定可靠，可明显提高脊柱融合率。

Steffee钢板治疗脊椎滑脱症38例报告

应用Steffee钢板复位固定加植骨融合治疗脊椎滑脱38例,21例得到完全复位,17例部分复位,滑脱率从术前平均31.4％减少到9％,无手术并发症;术后随访3～32个月,33例腰腿痛症状消失。X线片示植骨融合23例,术后半年内见植骨区模糊15例。作者认为本法是治疗脊椎滑脱的有效方法。

胸腰椎骨折的短段Steffee内固定术(附65例分析)

报告65例胸腰椎骨折的短段Steffee内固定术。其中单纯压缩型骨折10例，爆裂型骨折36例，骨折脱位型16例，安全带型骨折3例。41例获得5个月至4年10个月随访。骨折后后凸角平均22．7°，术后平均8°；脊椎前柱高度由术前71．3％恢复至术后86．5％。提出了椎弓根定位的新方法，即腰椎以根突基部乳状突为标志，乳状突前上方小凹为进钉点，胸推以后关节突的下关节实外线纵行垂线与横突中轴水平线的交点为进钉点。

改良Steffee钢板在腰骶椎内固定术中的应用解剖学

目的：为改良Ｓｔｅｆｆｅｅ钢板在腰骶椎内固定术中的应用提供解剖学基础。方法：在８具成人尸体标本上摹拟Ｌ５脊椎滑脱的Ｓｔｅｆｆｅｅ手术治疗。在Ｌ４～Ｓ１脊椎上分别安放Ｓｔｅｆｆｅｅ钢板和改良Ｓｔｅｆｆｅｅ钢板，比较２种内固定器械固定位置的解剖差异，并对１５副腰骶椎干燥骨标本做了经椎弓根内固定相关的数据测量。结果：传统的Ｓｔｅｆｆｅｅ钢板固定Ｓ１椎弓根螺钉安放困难，且进入椎管的机会多，或者是上２枚螺钉易套入钢板槽孔，而下面的螺钉难以套入钢板槽孔。改良Ｓｔｅｆｆｅｅ钢板可克服上述弊端，更符合局部解剖形态要求。结论：改良Ｓｔｅｆｆｅｅ钢板有科学的形态学依据，可临床试用。

周期性疲劳载荷下Steffee椎弓根钢板生物力学性质

分析Ｓｔｅｆｅｅ椎弓根钢板在疲劳载荷作用下，腰椎节段刚度和“融合”高度的变化．对４例新鲜成人男性腰椎标本（Ｌ２～Ｌ４），在Ｌ１和Ｌ３安放国产Ｓｔｅｆｅｅ椎弓根钢板，行Ｌ２椎体前２／３切除．在ＭＴＳ８５８双轴液压伺服生物材料试验系统上对标本施加疲劳压缩载荷（５００５０）Ｎ，疲劳３００００次，记录节段刚度和高度变化．结果：正常Ｌ１～Ｌ３节段刚度为５．５５ｋＮ／ｍｍ，Ｌ２椎体前２／３切除并安放Ｓｔｅｆｅｅ椎弓根钢板后刚度为０．２９ｋＮ／ｍｍ．在疲劳１００００次之前，相对刚度随疲劳次数的增大明显，之后相对刚度基本保持不变．疲劳３００００次后，刚度相对平均增加８０％．“融合”高度随疲劳次数的增加而减少，疲劳３００００次后，“融合”高度平均缩短３．７ｍｍ．建立的疲劳模型能较好地反映Ｓｔｅｆｅｅ椎弓根钢板的疲劳特性；器械固定后腰椎高度随周期性载荷作用而减少与椎弓根螺钉的折弯有关；在疲劳初期节段刚度随疲劳次数的增加而上升，反映了螺钉－骨界面间有一个相互适应的过程，这使得器械固定节段的刚度在疲劳后期维持不变．

Casson hybrid nanofluid flow over a Riga plate for drug deliveryapplications with double diffusion

Casson fluid-mediated hybrid nanofluids are more effective at transferring heat than traditional heat transfer fluids in terms of thermal conductivity.Heat exchangers,cooling systems and other thermal management systems are ideal for use with Casson fluids.Precise control of the flow and release of medication is necessary when using Casson fluids in drug delivery systems because of their unique rheological properties.Nanotechnology involves the creation of nanoparticles that are loaded with drugs and distributed in Casson fluid-based carriers for targeted delivery.In this study,to create a hybrid nanofluid,both single-walled carbon nanotubes(SWCNTs)and multi-walled carbon nanotubes(MWCNTs)are dispersed in a Casson fluid with Fourier’s and Fick’s laws assumptions.The Casson fluid is suitable for various engineering and medical applications due to the enhancement of heat transfer and thermal conductivity by the carbon nanotubes.Our objective is to understand how SWCNTs and MWCNTs impact the flow field by studying the flow behavior of the Casson hybrid nanofluid when it is stretched against a Riga plate.The Darcy-Forchheimer model is also used to account for the impact of the porous medium near the stretching plate.Both linear and quadratic drag terms are taken into account in this model to accurately predict the flow behavior of the nanofluid.In addition,the homotopy analysis method is utilized to address the model problem.The outcomes are discussed and deliberated based on drug delivery applications.These findings shed valuable light on the flow characteristics of a Casson hybrid nanofluid comprising SWCNTs and MWCNTs.It is observed that the incorporation of carbon nanotubes makes the nanofluid a promising candidate for medical applications due to its improved heat transfer properties.

Steffee钢板内固定治疗胸腰段爆裂型骨折合并脊髓损伤

目的 报告steffee钢板治疗胸腰段爆裂型骨折合并脊髓损伤的临床效果。方法 1995年以来共有34例胸腰段爆裂型骨折的病人接受了steffee钢板的治疗,随诊9～48个月。结果 Cobb角从术前平均16.8度到术后8.4度。CT扫描椎管面积也有很大改善。结论 steffee钢板对胸腰段爆裂型骨折是有效的。它结构简单,手术方便,固定牢固。

Steffee椎弓根钢板治疗腰椎滑脱并椎管狭窄症

Ｓｔｅｆｆｅｅ椎弓根钢板治疗腰椎滑脱并椎管狭窄症刘伟，方睿才，杨华，姚绍平，邹天南ＴｒｅａｔｍｅｎｔｏｆｌｕｍａｂｌｓｐｏｎｄｙｌｏｌｉｓｔｈｅｓｉｓｗｉｔｈｓｐｉｎａｌｓｔｅｎｏｓｉｓｂｙｓｔｅｆｆｃｃｐｃｄｉｃｌｅｓｃｒｃｗｐｌａｔｉｎｇＬｉｕＷ...

折弯steffee钢板治疗胸腰椎骨折的临床应用

目的与方法 :本文报告采用折弯的 steffee钢板内固定手术治疗胸腰椎骨折 30例。结果与讨论 :术前平均椎体前、后高度分别是 53.8%和 86.7% ,术后平均椎体前、后高度分别是 93.8%和98.2 %。术前 Cobb s角平均 2 4°,术后平均 6°。折弯后的 steffee钢板在使用时选择坚强的椎弓根为支点 ,能够呈受较大的螺旋提拔力及增强轴向撑开力 ,操作简单 ,骨折复位完全。但一年后高度有丢失 ,分析原因可能与

Local Bifurcation of a Thin Rectangle Plate with the Friction Support Boundary

The dynamical equations of a thin rectangle plate subjected to the friction support boundary and its plane force are established in this paper. The local bifurcation of this system is investigated by using L S method and the singularity theory. The Z 2 bifurcation in non degenerate case is discussed. The local bifurcation diagrams of the unfolding parameters and the bifurcation response characters referred to the physical parameters of the system are obtained by numerical simulation. The results of the computer simulation are coincident with the theoretical analysis and experimental results.

Nonlinear flutter of a two-dimension thin plate subjected to aerodynamic heating by differential quadrature method

The problem of nonlinear aerothermoelasticity of a two-dimension thin plate in supersonic airflow is examined. The strain-displacement relation of the von Karman＇s large deflection theory is employed to describe the geometric non-linearity and the aerodynamic piston theory is employed to account for the effects of the aerodynamic force. A new method, the differential quadrature method （DQM）, is used to obtain the discrete form of the motion equations. Then the Runge-Kutta numerical method is applied to solve the nonlinear equations and the nonlinear response of the plate is obtained numerically. The results indicate that due to the aerodynamic heating, the plate stability is degenerated, and in a specific region of system parameters the chaos motion occurs, and the route to chaos motion is via doubling-period bifurcations.

Development of S11306+SA516Gr70 roll-bonded clad steel plate for pressure vessels

To meet the demand of the pressure vessel industry, Baosteel has developed an S11306 ＋ SA516Gr70 roll-bonded clad steel plate. Comprehensive inspections of the composition, microstructure, and properties are performed to systematically evaluate the steel plate in normalized state and normalized ＋ stress relieved state. The results show the cladding interface of the Sl1306 ＋ SA516Gr70 roll-bonded clad steel plate has high shear strength, and the base metal has good mechanical properties. The performance is fully consistent with the technical requirements of the roll-bonded clad steel plate for pressure vessels.

Hydroelastic Response of VLFS with An Attached Submerged Horizontal Solid/Porous Plate Under Wave Action

The hydroelastic responses of a submerged horizontal solid/porous plate attached at the front of a very large rectangular floating structure(VLFS)under wave action has been investigated in the context of linear water wave theory.Darcy’s law is adopted to represent energy dissipation in pores.It is assumed that the porous plates are made of material with very fine pores so that the normal velocity across the perforated porous is linearly associated with the pressure drop.In the analytic method,the eigenfunction expansion-matching method(EEMM)for multiple domains is applied to solve the hydrodynamic problem and the elastic equation of motion is solved by the modal expansion method.The performance of the proposed submerged horizontal solid/porous plate can be significantly enhanced by selecting optimal design parameters,such as plate length,horizontal position,submerged depth and porosity.It is concluded that good damping effect can be achieved through installation of solid and porous plate.Porous plate has better damping effect at low frequencies,while solid plate has better damping effect at high frequencies.The optimal ratio of plate length to water depth is 0.25-0.375,and the optimal ratio of submerged depth to water depth is 0.09-0.181.

Non-axisymmetrical vibration of elastic circular plate on layered transversely isotropic saturated ground

The non-axisymmetrical vibration of elastic circular plate resting on a layered transversely isotropic saturated ground was studied. First, the 3-d dynamic equations in cylindrical coordinate for transversely isotropic saturated soils were transformed into a group of governing differential equations with 1-order by the technique of Fourier expanding with respect to azimuth, and the state equation is established by Hankel integral transform method, furthermore the transfer matrixes within layered media are derived based on the solutions of the state equation. Secondly, by the transfer matrixes, the general solutions of dynamic response for layered transversely isotropic saturated ground excited by an arbitrary harmonic force were established under the boundary conditions, drainage conditions on the surface of ground as well as the contact conditions. Thirdly, the problem was led to a pair of dual integral equations describing the mixed boundaryvalue problem which can be reduced to the Fredholm integral equations of the second kind solved by numerical procedure easily. At the end of this paper, a numerical result concerning vertical and radical displacements both the surface of saturated ground and plate is evaluated.

Wave Interaction with Dual Circular Porous Plates

In this paper we have investigated the reflection and the transmission of a system of two symmetric circular-arc-shaped thin porous plates submerged in deep water within the context of linear theory. The hypersingular integral equation technique has been used to analyze the problem mathematically. The integral equations are formulated by applying Green＇s integral theorem to the fundamental potential function and the scattered potential function into a suitable fluid region, and then using the boundary condition on the porous plate surface. These are solved approximately using an expansion-cure-collocation method where the behaviour of the potential functions at the tips of the plates have been used. This method ultimately produces a very good numerical approximation for the reflection and the transmission coefficients and hydrodynamic force components. The numerical results are depicted graphically against the wave number for a variety of layouts of the arc. Some results are compared with known results for similar configurations of dual rigid plate systems available in the literature with good agreement.

Nonlinear dynamic analysis of moving bilayer plates resting on elastic foundations

The aim of this study is to investigate the dynamic response of axially moving two-layer laminated plates on the Winkler and Pasternak foundations. The upper and lower layers are formed from a bidirectional functionally graded(FG) layer and a graphene platelet(GPL) reinforced porous layer, respectively. Henceforth, the combined layers will be referred to as a two-dimensional(2D) FG/GPL plate. Two types of porosity and three graphene dispersion patterns, each of which is distributed through the plate thickness,are investigated. The mechanical properties of the closed-cell layers are used to define the variation of Poisson’s ratio and the relationship between the porosity coefficients and the mass density. For the GPL reinforced layer, the effective Young’s modulus is derived with the Halpin-Tsai micro-system model, and the rule of mixtures is used to calculate the effective mass density and Poisson’s ratio. The material of the upper 2D-FG layer is graded in two directions, and its effective mechanical properties are also derived with the rule of mixtures. The dynamic governing equations are derived with a first-order shear deformation theory(FSDT) and the von Kármán nonlinear theory. A combination of the dynamic relaxation(DR) and Newmark’s direct integration methods is used to solve the governing equations in both time and space. A parametric study is carried out to explore the effects of the porosity coefficients, porosity and GPL distributions, material gradients, damping ratios, boundary conditions, and elastic foundation stiffnesses on the plate response. It is shown that both the distributions of the porosity and graphene nanofillers significantly affect the dynamic behaviors of the plates. It is also shown that the reduction in the dynamic deflection of the bilayer composite plates is maximized when the porosity and GPL distributions are symmetric.

Bending of orthotropic plates resting on Pasternak's foundations using mixed shear deformation theory

The mixed first-order shear deformation plate theory（MFPT） is employed to study the bending response of simply-supported orthotropic plates.The present plate is subjected to a mechanical load and resting on Pasternak＇s model or Winkler＇s model of elastic foundation or without any elastic foundation.Several examples are presented to verify the accuracy of the present theory.Numerical results for deflection and stresses are presented.The proposed MFPT is shown simplely to implement and capable of giving satisfactory results for shear deformable plates under static loads and resting on two-parameter elastic foundation.The results presented here show that the characteristics of deflection and stresses are significantly influenced by the elastic foundation stiffness,plate aspect ratio and side-to-thickness ratio.