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关键词

DX桩 2

力学性能 2

单边直线感应电机 2

沉降 2

3D打印 1

COVID-19 1

CP）；符号间干扰（inter symbol interference， ISI）；载波间干扰（inter carrier interference 1

Chebyshev多项式 1

Cu(In 1

DNA结构 1

Ga)Se2 1

ICI）；最大似然估计（maximum likelihood estimation 1

LMS 1

Lagrange方程 1

MLE） 1

OFDM）；快速傅立叶变换（Fast Fourier transform， FFT）；循环前缀（cyclic prefix 1

PPP项目 1

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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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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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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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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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一种通过循环前缀再利用改善OFDM系统带宽的新型节能ICI消除技术 Article

Sandeep SAROWA, Harmanjeet SINGH, Sunil AGRAWAL, B. S. SOHI

《信息与电子工程前沿（英文）》 2017年 第18卷 第11期   页码 1892-1899 doi: 10.1631/FITEE.1601333

摘要： 本文基于接收端循环前缀（cyclic prefix, CP）再利用，提出了一种节能且具有有效带宽的新技术来消除ICI。

关键词： orthogonal frequency division multiplexing     OFDM）；快速傅立叶变换（Fast Fourier transform， FFT）；循环前缀（cyclic prefix     CP    

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Crystallographic orientation effect on cutting-based single atomic layer removal

Wenkun XIE, Fengzhou FANG

《机械工程前沿（英文）》 2020年 第15卷 第4期   页码 631-644 doi: 10.1007/s11465-020-0599-x

摘要： The ever-increasing requirements for the scalable manufacturing of atomic-scale devices emphasize the significance of developing atomic-scale manufacturing technology. The mechanism of a single atomic layer removal in cutting is the key basic theoretical foundation for atomic-scale mechanical cutting. Material anisotropy is among the key decisive factors that could not be neglected in cutting at such a scale. In the present study, the crystallographic orientation effect on the cutting-based single atomic layer removal of monocrystalline copper is investigated by molecular dynamics simulation. When undeformed chip thickness is in the atomic scale, two kinds of single atomic layer removal mechanisms exist in cutting-based single atomic layer removal, namely, dislocation motion and extrusion, due to the differing atomic structures on different crystallographic planes. On close-packed crystallographic plane, the material removal is dominated by the shear stress-driven dislocation motion, whereas on non-close packed crystallographic planes, extrusion-dominated material removal dominates. To obtain an atomic, defect-free processed surface, the cutting needs to be conducted on the close-packed crystallographic planes of monocrystalline copper.

关键词： ACSM     single atomic layer removal mechanism     crystallographic orientation effect     mechanical cutting     Manufacturing III    

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Design and analysis of partially decoupled translational parallel mechanisms with single-loop structures

《机械工程前沿（英文）》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0695-1

摘要： This study presents a family of novel translational parallel mechanisms (TPMs) with single-loop topological structures. The proposed mechanism consists of only revolute and prismatic joints. The novel TPMs are simpler in structure and have fewer joints and components than the well-known Delta Robot. Four types of 2-degree of freedom driving systems are applied to different limb structures to avoid the moving actuator that causes the problem of increased moving mass. Four sample TPMs are constructed using the synthesized limbs, and one of them is investigated in terms of kinematic performance. First, a position analysis is performed and validated through numerical simulation to reveal the characteristics of partially decoupled motion, which improves the controllability of TPM. Second, singular configurations are identified, and the resulting singularity curve is obtained. Lastly, the workspace of TPM is analyzed, and the relationship between the singular configurations and the reachable workspace is explored. The workspace of the 3-CRR (C denotes the cylindrical joint and R denotes the revolute joint) translational mechanism is also presented to prove that the proposed TPM has a fairly large workspace.

关键词： translational parallel mechanism     single loop     multiple driving system     workspace analysis     singularity    

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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 L1F1C 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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Moving policy and regulation forward for single-use plastic alternatives

《环境科学与工程前沿（英文）》 2021年 第15卷 第3期 doi: 10.1007/s11783-021-1423-5

摘要： Single-use plastics are often used once or cannot be reused for extended periods. They are widely consumed with the rapid development of social economy. The waste generated by single-use plastics threatens ecosystem health by entering the environment and ultimately restricts sustainable human development. The innovation of sustainable and environmentally friendly single-use plastic alternative materials and the joint participation of governments, enterprises and the public are promising technologies and management approaches that can solve the problem of single-use plastics wastes. The development of single-use plastic alternative products can be promoted fundamentally only by improving relevant legislation and standards, providing differentiated industrial policies, encouraging scientific and technological innovation and expanding public participation.

关键词： Single-use plastic alternatives     Policy     Regulation     Sustainable development    

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Solvability and thermal response of cellulose with different crystal configurations

Qian CHEN, Kai ZHENG, Qingtao FAN, Kun WANG, Haiyan YANG, Jianxin JIANG, Shijie LIU

《工程管理前沿（英文）》 2019年 第6卷 第1期   页码 62-69 doi: 10.1007/s42524-019-0001-z

摘要：

Cellulose is a biodegradable and renewable natural material that it is naturally resistant to breaking and modification. Moreover, the crystalline structure of cellulose is a major factor restricting its industrial utilization. In this study, cellulose polymorphs were prepared from natural cellulose, and their solvability and thermal response were investigated. Using liquid- and solid-state NMR signals, the distinct types and dissolving states of cellulose polymorphs were identified. The thermal behavior of the polymorphic forms of cellulose-d was also evaluated, and cellulose II exhibited the poorest thermal stability and a unique exothermic reaction.

关键词： cellulose     crystal structure     thermal response     XRD     CP/MAS 13C NMR    

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Damage propagation and strength prediction of a single-lap interference-fit laminate structure

Peng ZOU, Xiangming CHEN, Hao CHEN, Guanhua XU

《机械工程前沿（英文）》 2020年 第15卷 第4期   页码 558-570 doi: 10.1007/s11465-020-0591-5

摘要： Experimental and finite element research was conducted on the bolted interference fit of a single-lap laminated structure to reveal the damage propagation mechanism and strength change law. A typical single-lap statically loading experiment was performed, and a finite element damage prediction model was built based on intralaminar progress damage theory. The model was programmed with a user subroutine and an interlaminar cohesive zone method. The deformation and damage propagation of the specimen were analyzed, and the failure mechanism of intralaminar and interlaminar damage during loading was discussed. The effect of secondary bending moment on load translation and damage distribution was revealed. The experimental and simulated load–displacement curves were compared to validate the developed model’s reliability, and the ultimate bearing strengths under different fit percentages were predicted. An optimal percentage was also recommended.

关键词： single-lap     interference fit     secondary bending moment     damage mechanism     bearing strength    

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Novel casting processes for single-crystal turbine blades of superalloys

Dexin MA

《机械工程前沿（英文）》 2018年 第13卷 第1期   页码 3-16 doi: 10.1007/s11465-018-0475-0

摘要：

This paper presents a brief review of the current casting techniques for single-crystal (SC) blades, as well as an analysis of the solidification process in complex turbine blades. A series of novel casting methods based on the Bridgman process were presented to illustrate the development in the production of SC blades from superalloys. The grain continuator and the heat conductor techniques were developed to remove geometry-related grain defects. In these techniques, the heat barrier that hinders lateral SC growth from the blade airfoil into the extremities of the platform is minimized. The parallel heating and cooling system was developed to achieve symmetric thermal conditions for SC solidification in blade clusters, thus considerably decreasing the negative shadow effect and its related defects in the current Bridgman process. The dipping and heaving technique, in which thin-shell molds are utilized, was developed to enable the establishment of a high temperature gradient for SC growth and the freckle-free solidification of superalloy castings. Moreover, by applying the targeted cooling and heating technique, a novel concept for the three-dimensional and precise control of SC growth, a proper thermal arrangement may be dynamically established for the microscopic control of SC growth in the critical areas of large industrial gas turbine blades.

关键词： superalloy     investment casting     Bridgman process     directional solidification     single crystal     turbine blade    

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Numerical analysis of bearing behaviors of single batter piles under horizontal loads in various directions

《结构与土木工程前沿（英文）》 2023年 第17卷 第2期   页码 224-237 doi: 10.1007/s11709-022-0914-1

摘要： The horizontal bearing behavior of a single batter pile (SBP) is vital to its application in practical engineering; however, the horizontal responses of SBPs change with the directions of horizontal loads, and this phenomenon is rarely investigated. Therefore, the directional differences in the horizontal bearing behaviors of SBPs are investigated in this study. Four model tests are conducted to preliminarily examine the effects of the skew angle of horizontal loads on the horizontal bearing capacities and distributions of the bending moments of the SBPs. Subsequently, the differences in the responses of the SBPs under horizontal loads in various directions at full scale are analyzed comprehensively via finite-element (FE) analysis. The effects of the skew angle on SBP-soil interaction are discussed. Moreover, an empirical design method is proposed based on the FE analysis results to predict the bearing ratios of SBPs in medium-dense and dense sand while considering the effects of the skew angle, batter angle, and pile diameter. The method is confirmed to be effective, as confirmed by the close agreement between the predicting results with the model test (reported in this study) and centrifuge model test results (reported in the literature).

关键词： single batter pile     skew horizontal load     model test     finite-element analysis     empirical design method    

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标题 作者 时间 类型 操作

Computer-Aided Design System for CP Single-Screw Compressor

SHEN Jing-feng, YAO Fu-sheng

期刊论文

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

Hong HE, Jianguo ZHOU,

期刊论文

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

期刊论文

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

Zhengbao LEI, Shubin WEI, Qingyun DU

期刊论文

A rolling 3-UPU parallel mechanism

Zhihuai MIAO, Yan’an YAO, Xianwen KONG

期刊论文

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

期刊论文

一种通过循环前缀再利用改善OFDM系统带宽的新型节能ICI消除技术

Sandeep SAROWA, Harmanjeet SINGH, Sunil AGRAWAL, B. S. SOHI

期刊论文

Crystallographic orientation effect on cutting-based single atomic layer removal

Wenkun XIE, Fengzhou FANG

期刊论文

Design and analysis of partially decoupled translational parallel mechanisms with single-loop structures

期刊论文

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

期刊论文

Moving policy and regulation forward for single-use plastic alternatives

期刊论文

Solvability and thermal response of cellulose with different crystal configurations

Qian CHEN, Kai ZHENG, Qingtao FAN, Kun WANG, Haiyan YANG, Jianxin JIANG, Shijie LIU

期刊论文

Damage propagation and strength prediction of a single-lap interference-fit laminate structure

Peng ZOU, Xiangming CHEN, Hao CHEN, Guanhua XU

期刊论文

Novel casting processes for single-crystal turbine blades of superalloys

Dexin MA

期刊论文

Numerical analysis of bearing behaviors of single batter piles under horizontal loads in various directions

期刊论文