Abstract:本文介绍了计算流体动力学（CFD）在模拟心血管系统血流的进展。特别在分流术支架血液动力学方面的应用。最后给出了两个支架血液动力学的模型,利用CFD技术计算了速度向量场和沿支架管壁的切剪应力分布,得出了在分流动脉内较理想流动的条件。

Abstract:To evaluate the stability of thoraclumbar spine after longitudinal impact with different energy. Methods: The fresh specimens of T12-L2 and L2-L5 were divided into three groups and were impacted with three different energy separately. Three dimensional motion were tested and roentgenograms and CT scan were taken before and after the impact. Results: Motion of superior or inferior lumbar were not changed after lower energy impact; but it increased after medial energy impact; after high energy impact the motion increased significantly(P<0.05). Conclusions: Three dimensional motion test is better than radiodiagnosis to evaluate the stability of thoraclumbar in laboratory.

Abstract:Using tresh cadaveric knee jiont specimens, the author makes systematic experimental researcheson the ligament viscoelasticity property of the anterior cruciate ligament and its replacements thepatellar ligament and the illiotibial tract. The author establishes the viscoelasticity mechanicalmodel,deduces the constitute equation of the anterior cruciate ligament, the patellar ligament andilliotibial tract, makes systematic analyses of the creep and loose phenomenon of the ligament. Theresults indicate that ligament failure is connected with its biomechanical properties, theviscoelasticity property of patellar ligament is more like that of the anterior cruciate ligament, theintra-articular substitution using the patellar ligament is better than using illiotibial tract.

Abstract:The Representative Volume Element (RVE) approach by homogenization theory was used to investigate the stiffness of cancellous bones. Two-level micro-structural model for canceilous bones was proposed, in which the trabeculae and cancellous bone are separately simulated in order to consider the influence of the structure of trabeculae. It is shown that the relation between the elasticity and the apparent density for cancellous bone is nearly linear. Results obstained from two-level model are higher than those from the isotropic model.

Abstract:It is important about the correlative study between hemorheology and cerebral heraodynamics forthe diagnosis and teatment of cerebral vascular diseases. The results of the correlative study on thepatients with hypertension.cerebral infarction and non-cardio-vascular disease in this study haveshowed that, the parameters of cerebral hemodynamics are obviousely affected by the hematocrit,these parameters are also correlative with other hemorheologic parameter-high shear stressviscosity of whole blood, plasma viscosity, low shear stress viscosity of whole blood, erythrocyteaggregation index, erythrocyte sedimentation.The effect degree of hematocrit on the cerebralhemodynamics parameters is diastolic pressure, dilation index of blood vessels, cerebral vascularresistance,critical pressure, transmission velocity of waves in cerbral artery from high to low. Thecomparison of parameters between cerebral hemodynamics and emorheology show that the former iscloser than the later on the correlative with the pathologic changes of hypertension and cerebral infarction.

Abstract:Four specimrens of human carvical spine (C1C7) were selected from fresh cadavers and made into samples for biomedchanical laboratory testiy. The measured critical value of stability loss for normal and healthy cervical spine is 887N, while the ultimate strength 1457N. The magnititudes of these 2 partraeters redueced to 601N and 880N respectively following resection of C5-6. disc. The results indicate that after injury of the disc, the resistance of the cervical spine to external force decreases and futher acute and chronic injury of cervical spine may easily occur.

Abstract:Pedicle screw fixation in osteoprotic bone is known to be poor. This study was designed to compare four methods which can improve the screw fixation stiffness. Seven cadaveric lumbar spines with osteoprosis were obtained and BMD was evaluated using a DEXA.A11 spines were separated into 35 vertebraes, and then divided into five groups randomly. The screw were inserted using one of the five methods: (1)two screw in the same vertbrae were linked with transverse plate; (2)with bone cement into screw hole; (3)with bone pieces picked into screw hole;(4)be instead by using a larger diameter screw; and (5)with simple Dick screw fixation as control. Axial pull-out force and screw displacement were measured. The results showed that: the pull-out force was increased (compared with group 5) 93% (P<0.01) in groupl, about onefold (P<0.01) in group 2, 139% (P<0.01) in group3 and 33% (P>0.05) in group 4. It is concluded that: transverse plate, bone cement, bone pieces can improve the stability of screw. But when the vertbrae with serious osteoprosis, these methods are no clinical value. There is no significant ents with serious osteoprosis.

Abstract:Aggregatability is one of the most important rheological properties of erythrocyte which is determined under blood flow condition at low shear rates. Several physiological characters of erythrocyte aggregation were reviewed in details, especially in aspects of occurring conditions effective factors and pathological abnormalities.

Abstract:The two methods of hone-needle fixation in treatment of femaralneck fracture were compared and analysed on the stability in theory and experiment. The results showed that curve needle fixation is superior to straight needle fixation.

Abstract:In this paper, based on the anatomical characteristics in the median sagittal section and the lateral radiograph of the human knee joint, the articula surface equations of the femur-tibia and the femur-patella in the sagittal plane are respectively established by employing polynomial functions and by use of the digitizer and the least squares curve fitting.

Abstract:Diabetics were examined with CBA. It was found that D, R, W, Z, and Qmean were 5 major indices in monitoring the trends of cerebrovascular hemodynamics of deabetics. Abnormalities of CVDI indicated that there were inadequate blood supply, microcirculation obstruction, cerebrovascular sclerosis, and disfunction of vscular regulation. CVDI abnormalities in type-1 diabetics were slight and bilateral, but in type-2 diabetics they could be bilateral or unilateral. Severe abnormalities were all detected in type-2 cases. When Cerebrovascular disease (CVD) occured with type-2 diabetes, it. was charactered by cerebrovascular sclerosis.microcirculation obstruction, hemobynamics abnormalities of small vascular under locded-in state and critical pressure increase, and these characteristics of CVDI can be taken as preliminary manifestation of CVD, which should be testified by CT examination.