Abstract:In this study the expression and the main affecting factor of myopia correction effect were deducedand analyzed according to the refraction fundamentals. On the basis of the known biomechanicalproperty and mechanical structure of the cornea, by means of the finite element method,computerized geometric models and biomechanical models of moderate myopic cornea for thesimulation of the refractive surgery were established. Some operational parameters, such asintraocular pressure, optical zone radius, cut number, incision depth in the RK operation wereanalyzed, and their influence on the operational outcome was computed and systematicallyanalyzed. Some valuable references are provided for the clinical practive.

Abstract:To evaluate the biomechanical differences of pure or combined application of severalposterior atlantoaxial fixation techniques. Methods: The torques needed for five-degree rotationwere measured in seven preserved atlantoaxial complex specimens after these specimens werefi-cated with transarticular screw fixation(Magerl), Magerl plus Gallie wiring, Magerl plus Brookswiring, pure Gallie wiring, pure Brooks wiring, and pure Halifax interlaminar clamping,respectively. Results: The torque for Mager were 6.59 1.34Nm, which were significant greater thanthe torque for any other pure fixation techniques(p<0.0l), but less than the torque for Magerl plusBrooks wiring(p<0.01). No significant difference was found between the torque for Magerl and forMagerl plus Gallie wiring. The torque for Gallie wiring were the least among the posterioratlantoaxial fixation techniques studied. Conclusions: The Magerl technique is superior to othercommon posterior atlantoaxial fixation technique in anti-rota...更多tional capacity. It is not necessaryadding Gallie wiring to Magerl technique. 还原

Abstract:In this paper, pulsative flow through a vessel with mild stenosis amplitude oscillating radically wasinvestigated. Velocities and wall shear stress were obtained by solving linearlzed N-S equations andWall equation. Results showed stenosis parameters had effect on blood flow. Variations in velocitywas sever and maximum wall shear stress reached peak value at stenosis amplitude oscillatingfrequency near the flow basic frequency.

Abstract:Hepatic portal vein is an important vein in hepatic blood vessels system. To study the mechanicalproperties of the portal vein is helpful to the researchwork of hepatic rheology, and offers a usefultheory in artificial blood vessels, hepatic transplantation, portal hypertension and so on. By theresearch of the residual strain of rat portal vein so as to lay the fundamental of studying themechanical properties and for building the pathological animal model of rat portal vein.By obtaining the following parameters thickness of blood vessel wall at no-load state and theopening angle of blood vessel of zero-stress state it is able to calculate the circumferential residualstrain of blood vessel at no-load state. The experimental results showed that Ee outer wall ispositive Eiinner wall negative and the residual strain of hepatic portal vein is little because itsvessel wall is very thin

Abstract:Based on the ultra structure properties of bone, the constitutive relation of lamellae bone and theultra structural model of osteon were provided with the method in the mechanics of composites. Theaxisymmetry strain problem of the osteon was solved. This model shows that the elastic coefficientsof conical bone are not only the function of bone porosity, but also the functions of the content ofcollagen and mineral and the orientation of collagen fibres.

Abstract:To establish the best configuration of fixation for distal humerus fracture. Method : Afterdistal humerus osteotomy, different fixations were applied for different specimens, include crosscancellous screws, single 'Y' type plate, 'J' type plate, 1/3 tubular plate and reconstruction plate.'Three-point bending' test was applied to measure the biomechanical strength of anterior-posteriorbending and medial-lateral bending. Result: Two plate construct placing at 90"(the medial one atulna side,and the other at posterior- lateral) is the most rigidity and stability(ANOVA, P<0.01).Conclusion: Because two plate system to fix the distal humerus fracture reconstructed the humerusdistal triangle structure which is consisted of medial, lateral columns and burneral trochlea, it isthe most rigid fixation.

Abstract:To evaluate the effects of glucocorticoids(GC) on conical bone and cancellous bone inrats with biomechanical way. Methods: Nineteen male Sprague-Dawley rats were randomly dividedinto Basal, Aging and Hormone group, the latter was given prednisone acetate (4.5mg/kg) twice aweek. The torsion, three-point bending and compression tests were respectively made on femurs and3ird--5th lumbar vertebrae of three groups after 3 months. Results: In GC group, the loads imposedon the femoral middle segments in three-point bending and on the lumbar vertebral(no-vertebralarch) in compression tests were separately decreased by 17.1 %(p<0.05) and 29.9%(p<0.05) thoughthe rest parameters tended to decrease, compared with the control group. Conclusions When GCused for a long time, the biomechanical characters of conical and cancellous bone in the rats wouldbe led to decrease and bone fracture be prone to occur.

Abstract:The Franctures have been fixed by using L- shaped condyle steel plate+bolt. L - shapedcondyle steel plate and compressed steel plate+bolt fixation. These three different internal fixationmethods have been compared in order to provide scientific basis for clinical practices. Methods To 9fresh cadaver femora samples, we perform mechanics analysis for the internal fixation of femoracondyle experimentally using stress analysis and theoretically using finite element method(FEM).Results It has been proved that the internal fixation using L- shaped condyle steel plate+bolt isbetter than that using L- shaped condyle steel plate and compressed steel plate+b(ilt. There existdistinct differences in stress and displacement between two condyles(p<0.01). Conclusion Thecombined fixation of L - shaped condyle stress plate+bolt is a very good internal fixation methodfor curing the fracture of femora condyle. It deserves to be put into application and populatization.

Abstract:In order to provide the scientific bats for clinical application, we analysed thebiomechanic of self-designed multi-function femoral plate(MFFP) on unstable intertrochantericfracture of femur. Methods: Four sensitive load cell were laid on the medial and lateral of proximalfemurs of twelve fresh cadaver to analyse the stress and strength. Results: The results showed thatMFFP system can lower the stress of femoral calcar and increase the stability of fracture, while thedynamic hip screw(DHS), slide hip screw and dynamic condyle screw(DCS) increase the stress offermoral calcar and lower the stability of fracture. The results also showed that inherent stress andstrength of the MFFP system can improve and suit the mechanical environment of bonere-establishement and intention of the instability of proximal femoral fracture. Conclusions: TheMFFP system has the follwing advantages, namely propel design with reliable biomechanicalperfomance, possesses more effctive ability of anti-rotation, three-dimensional fixation and easy tohandle. Therefore, it is worth popularization.

Abstract:Objectived:To study the hemorheological characteristics of male and female patientssuffered from coronary heart disease (CHD) in zhanjiang city. Methods f Routine hemorheologicaltests were carried out in 87 cases of male and female CHD patients with 380 normal people served ascontrol. Results: In male and female CHD patients, erythrocyte assemble was found and bloodcoagulation, blood density, blood plasma viscosity were higher than that of normal controls.Conclusion; Abnormality of the hemorheological characteristics were basically the same, but the causewhich give rise to the results are not completely corretated with each other.