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3D打印 1

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Effect of surgical factors on the augmentation of cement-injectable cannulated pedicle screw fixation

Haolin Sun, Chun Liu, Shunlun Chen, Yanjie Bai, Huilin Yang, Chunde Li, Lei Yang

《医学前沿（英文）》 2019年第13卷第5期页码 590-601 doi: 10.1007/s11684-019-0710-z

摘要： Bone cement-augmented pedicle screw system demonstrates great efficacy in spinal disease treatments. However, the intrinsic drawbacks associated with clinically used polymethylmethacrylate (PMMA) cement demands for new bone cement formulations. On the basis of our previous studies, a novel injectable and biodegradable calcium phosphate-based nanocomposite (CPN) for the augmentation of pedicle screw fixation was systematically evaluated for its surgical feasibility and biomechanical performance by simulated and animal osteoporotic bone models, and the results were compared with those of clinical PMMA cement. ASTM-standard solid foam and open-cell foam models and decalcified sheep vertebra models were employed to evaluate the augmentation effects of CPN on bone tissue and on the cement-injected cannulated pedicle screws (CICPs) placed in osteoporotic bone. Surgical factors in CICPs application, such as injection force, tapping technique, screw diameter, and pedicle screw loosening scenarios, were studied in comparison with those in PMMA. When directly injected to the solid foam model, CPN revealed an identical augmentation effect to that of PMMA, as shown by the similar compressive strengths (0.73±0.04 MPa for CPN group vs. 0.79±0.02 MPa for PMMA group). The average injection force of CPN at approximately 40–50 N was higher than that of PMMA at approximately 20 N. Although both values are acceptable to surgeons, CPN revealed a more consistent injection force pattern than did PMMA. The dispersing and anti-pullout ability of CPN were not affected by the surgical factors of tapping technique and screw diameter. The axial pullout strength of CPN evaluated by the decalcified sheep vertebra model revealed a similar augmentation level as that of PMMA (1351.6±324.2 N for CPN vs. 1459.7±304.4 N for PMMA). The promising results of CPN clearly suggest its potential for replacing PMMA in CICPs augmentation application and the benefits of further study and development for clinical uses.

关键词： bone cement pedicle screw degenerative spinal diseases calcium phosphate injectable

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New spinal robotic technologies

Bowen Jiang, Tej D. Azad, Ethan Cottrill, Corinna C. Zygourakis, Alex M. Zhu, Neil Crawford, Nicholas Theodore

《医学前沿（英文）》 2019年第13卷第6期页码 723-729 doi: 10.1007/s11684-019-0716-6

摘要： Robotic systems in surgery have developed rapidly. Installations of the da Vinci Surgical System (Intuitive Surgical, Sunnyvale, CA, USA), widely used in urological and gynecological procedures, have nearly doubled in the United States from 2010 to 2017. Robotics systems in spine surgery have been adopted more slowly; however, users are enthusiastic about their applications in this subspecialty. Spinal surgery often requires fine manipulation of vital structures that must be accessed via limited surgical corridors and can require repetitive tasks over lengthy periods of time — issues for which robotic assistance is well-positioned to complement human ability. To date, the United States Food and Drug Administration (FDA) has approved 7 robotic systems across 4 companies for use in spinal surgery. The available clinical data evaluating their efficacy have generally demonstrated these systems to be accurate and safe. A critical next step in the broader adoption of surgical robotics in spine surgery is the design and implementation of rigorous comparative studies to interrogate the utility of robotic assistance. Here we discuss current applications of robotics in spine surgery, review robotic systems FDA-approved for use in spine surgery, summarize randomized controlled trials involving robotics in spine surgery, and comment on prospects of robotic-assisted spine surgery.

关键词： robotics spine surgery Mazor ExcelsiusGPS ROSA pedicle screw

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Simulation of cottonseed cake melt flow in metering zone of a single screw extruder

Hong HE, Jianguo ZHOU,

《化学科学与工程前沿（英文）》 2010年第4卷第3期页码 263-269 doi: 10.1007/s11705-009-0276-4

摘要： Research on the extrusion of natural polymers (food, feed, etc.) is relatively new due to the complex physicochemical transformations of raw materials, although plastics melt conveying and transport have been well studied. The structure and composition, rheological behavior as well as extrusion processing of natural polymer are much more complicated. In this study, a quasi-three-dimensional (3D) fluid flow model for non-Newtonian, non-isothermal and undeveloped temperature was developed, the model prediction being in reasonably good agreement with the experiment. Results show that the influence of moisture content, among other process variables, is the most significant, followed by screw speed. Some interaction exists between these two variables and the screw speed effect becomes marginal at high moisture contents. In addition, viscosity change in the channel was studied.

关键词： quasi-three-dimensional rheological viscosity processing influence

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Computer-Aided Design System for CP Single-Screw Compressor

SHEN Jing-feng, YAO Fu-sheng

《机械工程前沿（英文）》 2006年第1卷第1期页码 21-25 doi: 10.1007/s11465-005-0018-3

摘要：

To design various optimum parameters and simulate the working process of CP single-screw compressor, the Computer-Aided Design (CAD) system for the CP single-screw compressor has been established. A new method based on computer graphics technology, database technology, object-oriented programming technology, and visual simulation technology has been adopted in this CAD system. The system has integrated solid modeling function with parameterization design function and animator simulation function based on analyzing the working principle of the CP single-screw compressor. The experimental results show that the CAD system for the CP single-screw compressor is practical and feasible.

关键词： CP single-screw database technology simulation technology programming technology animator simulation

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Explicit optimization method for cutting-screw-thread on the basis of dual-RSM

Zhengbao LEI, Shubin WEI, Qingyun DU

《机械工程前沿（英文）》 2010年第5卷第4期页码 423-430 doi: 10.1007/s11465-010-0109-7

摘要： To obtain the explicit function for optimizing the cutting-screw-thread (CST) in crash, the simulations of frontal crash at the speed of 56 km/h have been carried out in VPG. The peak acceleration in crash has been taken as the evaluation index of energy absorption characteristics. First, the single factor experiment was taken based on six parameters affecting on the absorption characteristics of CST. Second, the peak acceleration function of each parameter by using response surface method (RSM) is obtained. Third, the explicit resultant peak acceleration function of six parameters by using RSM again is obtained. A dual RSM-based explicit method is proposed. According to this function, the best size dimensions of CST in different crash conditions could be easily obtained. Finally, an example shows that the values of the calculation errors for simulation value and target value (40 g) are 3.6% and 1.3%, respectively. This method can satisfy the demand for engineering accuracy.

关键词： vehicle engineering crash safety explicit method response surface method

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A rolling 3-UPU parallel mechanism

Zhihuai MIAO, Yan’an YAO, Xianwen KONG

《机械工程前沿（英文）》 2013年第8卷第4期页码 340-349 doi: 10.1007/s11465-013-0282-6

摘要：

A novel rolling mechanism is proposed based on a 3-UPU parallel mechanism in this paper. The rolling mechanism is composed of two platforms connected by three UPU (universal-prismatic-universal) serial-chain type limbs. The degree-of-freedom of the mechanism is analyzed using screw theory. Gait analysis and stability analysis are presented in detail. Four rolling modes of the mechanism are discussed and simulated. The feasibility of the rolling mechanism is verified by means of a physical prototype. Finally, its terrain adaptability is enhanced through planning the rolling gaits.

关键词： parallel mechanism rolling mechanism screw theory

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动态变化滚珠丝杠进给系统的智能非同位控制策略

刘辉, 张俊, 赵万华

《工程（英文）》 2017年第3卷第5期页码 641-647 doi: 10.1016/J.ENG.2017.04.007

摘要：

滚珠丝杠进给驱动系统由于其细长的螺旋主轴和部件之间连接部分的灵活性，具有变化的高阶动态特性，并且当采用直线光栅尺进行直接位置测量时，它还具有非同位控制的明显特征。长期以来，动态特性和非同位状况一直是运动和振动控制困难的根源，它们还会降低轴的运动精度。在本研究中，考虑到灵活性及其变化，我们建立了基于频率的子结构动态模型，并充分研究了动态特性对位置变化的依赖，开发出由模态特征修正器（MCM）和智能自适应调整算法（ATA）组成的控制策略。MCM 由峰值滤波器和陷波滤波器组成，从而将设备动态变为虚拟同位系统，且可以避免控制溢出。使用人工神经网络（ANN）作为平滑参数插值器，可以实时更新滤波器的参数，以便应对进给驱动系统的动态变化。我们已经在实际的进给驱动系统中验证了所提出策略的有效性和鲁棒性。

关键词：滚珠丝杠进给驱动系统变化高阶动态非同位控制模态特征修正器智能自适应调整算法

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Design of a novel side-mounted leg mechanism with high flexibility for a multi-mission quadruped earth rover BJTUBOT

《机械工程前沿（英文）》 2023年第18卷第2期 doi: 10.1007/s11465-022-0740-0

摘要： Earth rover is a class of emerging wheeled-leg robots for nature exploration. At present, few methods for these robots’ leg design utilize a side-mounted spatial parallel mechanism. Thus, this paper presents a complete design process of a novel 5-degree-of-freedom (5-DOF) hybrid leg mechanism for our quadruped earth rover BJTUBOT. First, a general approach is proposed for constructing the novel leg mechanism. Subsequently, by evaluating the basic locomotion task (LT) of the rover based on screw theory, we determine the desired motion characteristic of the side-mounted leg and carry out its two feasible configurations. With regard to the synthesis method of the parallel mechanism, a family of concise hybrid leg mechanisms using the 6-DOF limbs and an L_1F1C limb (which can provide a constraint force and a couple) is designed. In verifying the motion characteristics of this kind of leg, we select a typical (3-UPRU&RRRR)&R mechanism and then analyze its kinematic model, singularities, velocity mapping, workspace, dexterity, statics, and kinetostatic performance. Furthermore, the virtual quadruped rover equipped with this innovative leg mechanism is built. Various basic and specific LTs of the rover are demonstrated by simulation, which indicates that the flexibility of the legs can help the rover achieve multitasking.

关键词： design synthesis parallel mechanism hybrid leg mechanism screw theory quadruped robot

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数控车床丝杠进给系统刚度对定位精度的影响

吴南星,胡如夫,孙庆鸿

《中国工程科学》 2004年第6卷第9期页码 46-49

摘要：

数控车床丝杠进给系统刚度对系统的失动量和定位精度影响较大。基于进给系统质量和弹簧力学模型，给出了进给系统轴向刚度和扭转刚度对失动量的影响与定位误差的解析表达式，为进给系统结构设计、降低系统的失动量和提高系统的定位精度提供了理论依据；结合实例进行了应用分析计算，取得了明显效果。

关键词：数控机床刚度失动量定位精度

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Numerical solution, simulation and testing of the thermal dynamic characteristics of ball-screws

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

《机械工程前沿（英文）》 2008年第3卷第1期页码 28-36 doi: 10.1007/s11465-008-0007-4

摘要： This research focuses on the characteristics of how a ball-screw changes its temperature corresponding to the periodic change of the end-most heat source. Based on the theory of heat transfer, this paper supplies a numerical solution to the non-homogeneous equation of heat transfer through the group explicit (GE) finite difference approach. The temperature distribution for the ball-screw at different times and directions is shown. By simulating and modeling the temperature field and thermal deformation of the ball-screw under periodically varying heat sources, this paper describes the thermal dynamic characteristics of the ball-screw under such conditions. By testing the thermal dynamic characteristics of the ball-screw, the numerical solution is validated.

关键词： numerical solution temperature corresponding temperature distribution end-most ball-screw

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轴向零泊松比结构心血管支架的设计、3D打印与表征 Article

王程锦, 张磊, 方永聪, 孙伟

《工程（英文）》 2021年第7卷第7期页码 979-990 doi: 10.1016/j.eng.2020.02.013

摘要：

药物洗脱支架固有的缺陷促进了生物可吸收心血管支架的研究与发展。近年来，增材制造技术（也称3D打印技术）在医疗器械领域得到了广泛的应用。本文提出了一种新型的微螺杆挤出式3D打印系统，并利用该系统制备了一种具有零泊松比（ZPR）结构的支架。首先进行了初步的单丝挤出试验来研究合适的制造参数；随后，制备了具有不同几何结构的3D打印支架，并通过扫描电子显微镜（SEM）观察分析支架表面形貌；最后，对不同参数的3D打印支架进行了力学性能评价和初步的生物学评价。总之，基于微螺杆挤出式3D打印系统具有制备个性化支架的潜力。

关键词：增材制造 3D打印螺杆挤出心血管支架零泊松比