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DSM（设计结构矩阵） 2

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Meshing stiffness property and meshing status simulation of harmonic drive under transmission loading

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0674-6

摘要： The multitooth meshing state of harmonic drive (HD) is an important basic characteristic of its high transformation precision and high bearing capacity. Meshing force distribution affects the load sharing of the tooth during meshing, and theoretical research remains insufficient at present. To calculate the spatial distributed meshing forces and loading backlashes along the axial direction, an iterative algorithm and finite element model (FEM) is proposed to investigate the meshing state under varied transmission loading. The displacement formulae of meshing point under tangential force are derived according to the torsion of the flexspline cylinder and the bending of the tooth. Based on the relationship of meshing forces and circumferential displacements, meshing forces and loading backlashes in three cross-sections are calculated with the algorithm under gradually increased rotation angles of circular spline, and the results are compared with FEM. Owing to the taper deformation of the cup-shaped flexspline, the smallest initial backlash and the earliest meshing point appear in the front cross-section far from the cup bottom, and then the teeth in the middle cross-section of the tooth rim enter the meshing and carry most of the loading. Theoretical and numerical research show that the flexibility is quite different for varied meshing points and tangential force amplitude because of the change of contact status between the flexspline and the wave generator. The meshing forces and torsional stiffness of the HD are nonlinear with the torsional angle.

关键词： harmonic drive     meshing flexibility matrix     meshing force     loading backlash     flexspline     contact analysis    

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Gear fault diagnosis using gear meshing stiffness identified by gearbox housing vibration signals

《机械工程前沿（英文）》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0713-3

摘要： Gearbox fault diagnosis based on vibration sensing has drawn much attention for a long time. For highly integrated complicated mechanical systems, the intercoupling of structure transfer paths results in a great reduction or even change of signal characteristics during the process of original vibration transmission. Therefore, using gearbox housing vibration signal to identify gear meshing excitation signal is of great significance to eliminate the influence of structure transfer paths, but accompanied by huge scientific challenges. This paper establishes an analytical mathematical description of the whole transfer process from gear meshing excitation to housing vibration. The gear meshing stiffness (GMS) identification approach is proposed by using housing vibration signals for two stages of inversion based on the mathematical description. Specifically, the linear system equations of transfer path analysis are first inverted to identify the bearing dynamic forces. Then the dynamic differential equations are inverted to identify the GMS. Numerical simulation and experimental results demonstrate the proposed method can realize gear fault diagnosis better than the original housing vibration signal and has the potential to be generalized to other speeds and loads. Some interesting properties are discovered in the identified GMS spectra, and the results also validate the rationality of using meshing stiffness to describe the actual gear meshing process. The identified GMS has a clear physical meaning and is thus very useful for fault diagnosis of the complicated equipment.

关键词： gearbox fault diagnosis     meshing stiffness     identification     transfer path     signal processing    

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基于层次优化的图像网格化方法

Hao XIE,Ruo-feng TONG

《信息与电子工程前沿（英文）》 2016年 第17卷 第1期   页码 32-40 doi: 10.1631/FITEE.1500171

摘要：

矢量图形作为光栅图像的一种几何表示形式，具有许多优点，例如，定义独立性和编辑功能。将栅格图像转换为矢量图形的一种流行方法是图像网格划分，其目的是找到一个网格以尽可能忠实地表示图像。对于传统的网格划分算法，问题的症结主要在于目标的高非线性度和非平滑度，这使得很难找到理想的最优解。为了改善这种情况，我们提出了一种层次优化算法，解决了从较粗级别到较细级别的问题，并为每个级别提供了其较粗的提升的初始化功能。为了进一步简化问题，将原始的非凸问题转换为线性最小二乘，从而变成凸的，这使问题更容易解决。字典学习框架用于将几何和拓扑完美地结合在一起。然后采用交替方案来求解两个部分。实验表明，对于大多数图像，该算法运行速度快，效果优于现有图像。

关键词： 图像网格化；层次优化；凸化    

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工程承包联营体的柔性分析与评价

赵振宇,殷音

《中国工程科学》 2008年 第10卷 第9期   页码 84-87

摘要：

讨论了工程承包联营体环境动荡性评价指标和工程承包联营体柔性评价指标以及相应的评价方法。通过柔性分析，可以判断出工程承包联营体各方面的柔性程度能否与其相应的环境和内外部因素相适应，并为制订调整联营体柔性度的措施提供帮助，进而提高联营体的管理水平和竞争力。

关键词： 工程项目     承包商     联营体     柔性管理    

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Effects of Boundary Condition and Helix Angle on Meshing Performance of TI Worm Gearing

SUN Yue-hai, DUAN Lu-qian, WANG Shu-ren, ZHANG Ce

《机械工程前沿（英文）》 2006年 第1卷 第1期   页码 90-95 doi: 10.1007/s11465-005-0006-7

摘要：

To exactly describe the contact state and contact area of tooth surface of toroidal involute (TI) worm gearing, the authors introduced boundary condition into contact line analysis.With helix angle chosen as parameter, the criterion for the existence of meshing boundary line on the surface of TI worm gearing is derived. Results show that there can be four situations for meshing boundary line on the tooth surface of gear, namely, inexistence of meshing boundary line, a unique line, two lines, and two coincident lines. If the helix angle is equal to or slightly smaller than the bigger angle, which makes two meshing boundary lines superpose, a preferable meshing performance is obtained. Computer simulation proves the validity of the above conclusion.

关键词： preferable     inexistence     Results     validity     boundary condition    

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Response in piled raft foundation of tall chimneys under along-wind load incorporating flexibility of

B. R. JAYALEKSHMI,S.V. JISHA,R. SHIVASHANKAR

《结构与土木工程前沿（英文）》 2015年 第9卷 第3期   页码 307-322 doi: 10.1007/s11709-015-0288-8

摘要： The present paper deals with the numerical analysis of tall reinforced concrete chimneys with piled raft foundation subjected to along-wind loads considering the flexibility of soil. The analysis was carried out using finite element method on the basis of direct method of soil-structure interaction (SSI). The linear elastic material behavior was assumed for chimney, piled raft and soil. Four different material properties of soil stratum were selected in order to study the effect of SSI. The chimney elevation and the thickness of raft of piled raft foundation were also varied for the parametric study. The chimneys were assumed to be located in terrain category 2 and subjected to a maximum wind speed of 50 m/s as per IS:875 (Part 3)-1987. The along-wind loads were computed according to IS:4998 (Part 1)-1992. The base moments of chimney evaluated from the SSI analysis were compared with those obtained as per IS:4998 (Part 1)-1992. The tangential and radial bending moments of raft of piled raft foundation were evaluated through SSI analysis and compared with those obtained from conventional analysis as per IS:11089-1984, assuming rigidity at the base of the raft foundation. The settlements of raft of piled raft foundation, deflection of pile and moments of the pile due to interaction with different soil stratum were also evaluated. From the analysis, considerable reduction in the base moment of chimney due to the effect of SSI is observed. Higher radial moments and lower tangential moments were obtained for lower elevation chimneys with piled raft resting on loose sand when compared with conventional analysis results. The effect of SSI in the response of the pile is more significant when the structure-foundation system interacts with loose sand.

关键词： finite element method     piled raft     tall chimney     soil-structure interaction     along-wind load    

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Decellularized extracellular matrix mediates tissue construction and regeneration

《医学前沿（英文）》 2022年 第16卷 第1期   页码 56-82 doi: 10.1007/s11684-021-0900-3

摘要： Contributing to organ formation and tissue regeneration, extracellular matrix (ECM) constituents provide tissue with three-dimensional (3D) structural integrity and cellular-function regulation. Containing the crucial traits of the cellular microenvironment, ECM substitutes mediate cell–matrix interactions to prompt stem-cell proliferation and differentiation for 3D organoid construction in vitro or tissue regeneration in vivo. However, these ECMs are often applied generically and have yet to be extensively developed for specific cell types in 3D cultures. Cultured cells also produce rich ECM, particularly stromal cells. Cellular ECM improves 3D culture development in vitro and tissue remodeling during wound healing after implantation into the host as well. Gaining better insight into ECM derived from either tissue or cells that regulate 3D tissue reconstruction or organ regeneration helps us to select, produce, and implant the most suitable ECM and thus promote 3D organoid culture and tissue remodeling for in vivo regeneration. Overall, the decellularization methodologies and tissue/cell-derived ECM as scaffolds or cellular-growth supplements used in cell propagation and differentiation for 3D tissue culture in vitro are discussed. Moreover, current preclinical applications by which ECM components modulate the wound-healing process are reviewed.

关键词： decellularized extracellular matrix     3D culture     organoids     tissue repair    

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Perspective of mixed matrix membranes for carbon capture

Shinji Kanehashi, Colin A. Scholes

《化学科学与工程前沿（英文）》 2020年 第14卷 第3期   页码 460-469 doi: 10.1007/s11705-019-1881-5

摘要： Polymeric membrane-based gas separation has found wide applications in industry, such as carbon capture, hydrogen recovery, natural gas sweetening, as well as oxygen enrichment. Commercial gas separation membranes are required to have high gas permeability and selectivity, while being cost-effective to process. Mixed matrix membranes (MMMs) have a composite structure that consists of polymers and fillers, therefore featuring the advantages of both materials. Much effort has been made to improve the gas separation performance of MMMs as well as general membrane properties, such as mechanical strength and thermal stability. This perspective describes potential use of MMMs for carbon capture applications, explores their limitations in fabrication and methods to overcome them, and addresses their performance under industry gas conditions.

关键词： membranes     polymeric     mixed matrix     impurities    

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Review of

Yang YU, Jiafu TANG

《工程管理前沿（英文）》 2019年 第6卷 第2期   页码 183-192 doi: 10.1007/s42524-019-0028-1

摘要： production is regarded as a new production mode and derived from the production site of Japanese electronics industry. This production mode is proposed to overcome the low flexibility of the assembly line. production has been successfully implemented in Japanese electronics industry, such as Canon and Sony. Benefits from production include rapid response, good flexibility, and high productivity. production has received extensive attention in academic research and production practice. This study reviews the background, characteristics, types, and operation of production. The advantages and applicable scenes of production are summarized from the perspective of business practice. We compare production and famous production modes, i.e., assembly line, cellular manufacturing, and Toyota Production System. The literature on production is surveyed and classified. Furthermore, future research directions are provided.

关键词： seru production     production mode     flexibility     literature review    

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

《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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Strengthening of reinforced concrete beams using fiber-reinforced cementitious matrix systems fabricated

《结构与土木工程前沿（英文）》   页码 1100-1116 doi: 10.1007/s11709-023-0967-9

摘要： The performance of a new fiber-reinforced cementitious matrix (FRCM) system developed using custom-designed mortar and fabrics is investigated in this study. The behavior of this system is evaluated in terms of both the flexural and shear strengthening of reinforced concrete beams. Eight beams are designed to assess the effectiveness of the FRCM system in terms of flexural strengthening, and four specimens are designed to investigate their shear behavior. The parameters investigated for flexural strengthening are the number of layers, span/depth ratio, and the strengthening method. Unlike previous studies, custom fabrics with similar axial stiffness are used in all strengthening methods in this study. In the shear-strengthened specimens, the effects of the span/depth ratio and strengthening system type (fiber-reinforced polymer (FRP) or FRCM) are investigated. The proposed FRCM system exhibits desirable flexural and shear strengthening for enhancing the load capacity, provides sufficient bonding with the substrate, and prevents premature failure modes. Considering the similar axial stiffness of fabrics used in both FRCM and FRP systems and the higher load capacity of specimens strengthened by the former, cement-based mortar performs better than epoxy.

关键词： fiber-reinforced cementitious matrix     flexural strengthening     shear strengthening     carbon fiber-reinforced polymer     shear span    

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A dynamic model of mobile concrete pump boom based on discrete time transfer matrix method

Wu REN, Yunxin WU, Zhaowei ZHANG

《机械工程前沿（英文）》 2013年 第8卷 第4期   页码 360-366 doi: 10.1007/s11465-013-0280-8

摘要：

Mobile concrete pump boom is typical multi-body large-scale motion manipulator. Due to posture constantly change in working process, kinematic rule and dynamic characteristic are difficult to solve. A dynamics model of a mobile concrete pump boom is established based on discrete time transfer matrix method (DTTMM). The boom system is divided into sub-structure A and sub-structure B. Sub-structure A is composed by the 1st boom and hydraulic actuator as well as the support. And sub-structure B is consists of the other three booms and corresponding hydraulic actuators. In the model, the booms and links are regarded as rigid elements and the hydraulic cylinders are equivalent to spring-damper. The booms are driven by the controllable hydraulic actuators. The overall dynamic equation and transfer matrix of the model can be assembled by sub-structures A and B. To get a precise result, step size and integration parameters are studied then. Next the tip displacement is calculated and compared with the result of ADAMS software. The displacement and rotation angle curves of the proposed method fit well with the ADAMS model. Besides it is convenient in modeling and saves time. So it is suitable for mobile concrete pump boom real-time monitoring and dynamic analysis. All of these provide reference to boom optimize and engineering application of such mechanisms.

关键词： multi-body     mobile concrete pump boom     discrete time transfer matrix method (DTTMM)     kinematic     dynamic     tip displacement    

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住宅建筑需求侧柔性——定义、柔性负荷及量化方法 Review

罗正意, 彭晋卿, 曹静宇, 殷荣欣, 邹斌, 谭羽桐, 严晋跃

《工程（英文）》 2022年 第16卷 第9期   页码 123-140 doi: 10.1016/j.eng.2022.01.010

摘要：

本文综述了近年来关于住宅建筑需求侧柔性的定义、柔性负荷及柔性量化方法方面的研究。首先，针对建筑需求侧柔性、运行柔性和能源柔性等不同的术语，进行了系统的比较和区分；其次，对住宅建筑主要柔性负荷的运行特性和柔性能力进行了总结和比较；再次，对柔性负荷的建模方法和柔性量化指标也进行了详细的综述和总结。最后，提出了当前建筑需求侧柔性领域存在的一些亟待解决的问题。研究结果表明当前针对住宅建筑需求侧柔性的研究主要以中央空调、储水式电热水器、湿电器、冰箱和照明为主，分别占现有研究的36.7%、25.7%、14.7%、9.2%和8.3%。这些柔性负荷在运行特性、使用频率和柔性能力
方面存在较大的差异，而对于它们实际的响应特性有待进一步研究。此外，本文给出了用于柔性负荷建模的白箱、灰箱和黑箱模型在不同应用场合下适用性的建议；对于柔性量化指标，现有研究主要从功率、时间、能量、效率、经济性和环保性等维度提出了大量的指标，但是缺少统一的柔性量化体系。本文能够帮助读者更好地理解建筑需求侧柔性、区分与柔性相关的不同的术语、了解住宅建筑不同柔性负荷的运行特性和柔性能力，同时也能为柔性负荷的建模和柔性量化的相关研究提供指导。

关键词： 住宅建筑     需求侧柔性     柔性负荷     建模方法     量化指标    

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Glycosylation of dentin matrix protein 1 is critical for fracture healing via promoting chondrogenesis

Hui Xue, Dike Tao, Yuteng Weng, Qiqi Fan, Shuang Zhou, Ruilin Zhang, Han Zhang, Rui Yue, Xiaogang Wang, Zuolin Wang, Yao Sun

《医学前沿（英文）》 2019年 第13卷 第5期   页码 575-589 doi: 10.1007/s11684-019-0693-9

摘要： Fractures are frequently occurring diseases that endanger human health. Crucial to fracture healing is cartilage formation, which provides a bone-regeneration environment. Cartilage consists of both chondrocytes and extracellular matrix (ECM). The ECM of cartilage includes collagens and various types of proteoglycans (PGs), which play important roles in maintaining primary stability in fracture healing. The PG form of dentin matrix protein 1 (DMP1-PG) is involved in maintaining the health of articular cartilage and bone. Our previous data have shown that DMP1-PG is richly expressed in the cartilaginous calluses of fracture sites. However, the possible significant role of DMP1-PG in chondrogenesis and fracture healing is unknown. To further detect the potential role of DMP1-PG in fracture repair, we established a mouse fracture model by using a glycosylation site mutant DMP1 mouse (S89G-DMP1 mouse). Upon inspection, fewer cartilaginous calluses and down-regulated expression levels of chondrogenesis genes were observed in the fracture sites of S89G-DMP1 mice. Given the deficiency of DMP1-PG, the impaired IL-6/JAK/STAT signaling pathway was observed to affect the chondrogenesis of fracture healing. Overall, these results suggest that DMP1-PG is an indispensable proteoglycan in chondrogenesis during fracture healing.

关键词： fracture     extracellular matrix     dentin matrix protein 1     proteoglycan     cartilage    

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Role of salivary matrix metalloproteinase-8 (MMP-8) in chronic periodontitis diagnosis

null

《医学前沿（英文）》 2015年 第9卷 第1期   页码 72-76 doi: 10.1007/s11684-014-0347-x

摘要：

Periodontitis is an inflammatory disease of the periodontium. Any imbalance between the matrix metalloproteinases (MMPs) secreted by neutrophils and tissue inhibitors initiates the destruction of collagen in gum tissue, leading to chronic periodontitis. This study aimed to correlate salivary levels of MMP-8 and periodontal parameters of chronic periodontitis to establish MMP-8 as a noninvasive marker for the early diagnosis of chronic periodontitis. The study involved 40 subjects visiting the periodontic OPD of Dr. Ziauddin Ahmad Dental College and Hospital, located in Aligarh, U.P., India, from 2011 to 2012. The subjects were divided into two groups: group I consisted of 20 periodontally healthy subjects (controls) while group II consisted of 20 patients with chronic periodontitis. Chronic periodontitis was assessed on the basis of several periodontal parameters, including pocket probing depth (PPD), clinical attachment level (CAL), gingival index (GI), and plaque index (PI). Around 3 ml of unstimulated and whole expectorated saliva was collected for MMP-8 estimation by ELISA using Quantikine human total MMP-8 immunoassay kits. Data were analyzed using STATISTICA (Windows version 6) software. Salivary MMP-8 levels of groups I and II were 190.91±143.89 ng/ml and 348.26±202.1 ng/ml, respectively. The MMP-8 levels and periodontal status (PPD, CAL, GI, and PI) of groups I and II showed positive and significant correlations (for PPD, r = 0.63, P<0.001; for CAL, r = 0.54, P<0.001; for GI, r = 0.49, P<0.001; and for PI, r = 0.63, P<0.001). The results of this study demonstrate elevated concentrations of MMP-8 in individuals with chronic periodontitis.

关键词： matrix metalloproteinase-8     chronic periodontitis     pocket probing depth     clinical attachment level     gingival index     plaque index    

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标题 作者 时间 类型 操作

Meshing stiffness property and meshing status simulation of harmonic drive under transmission loading

期刊论文

Gear fault diagnosis using gear meshing stiffness identified by gearbox housing vibration signals

期刊论文

基于层次优化的图像网格化方法

Hao XIE,Ruo-feng TONG

期刊论文

工程承包联营体的柔性分析与评价

赵振宇,殷音

期刊论文

Effects of Boundary Condition and Helix Angle on Meshing Performance of TI Worm Gearing

SUN Yue-hai, DUAN Lu-qian, WANG Shu-ren, ZHANG Ce

期刊论文

Response in piled raft foundation of tall chimneys under along-wind load incorporating flexibility of

B. R. JAYALEKSHMI,S.V. JISHA,R. SHIVASHANKAR

期刊论文

Decellularized extracellular matrix mediates tissue construction and regeneration

期刊论文

Perspective of mixed matrix membranes for carbon capture

Shinji Kanehashi, Colin A. Scholes

期刊论文

Review of

Yang YU, Jiafu TANG

期刊论文

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

期刊论文

Strengthening of reinforced concrete beams using fiber-reinforced cementitious matrix systems fabricated

期刊论文

A dynamic model of mobile concrete pump boom based on discrete time transfer matrix method

Wu REN, Yunxin WU, Zhaowei ZHANG

期刊论文

住宅建筑需求侧柔性——定义、柔性负荷及量化方法

罗正意, 彭晋卿, 曹静宇, 殷荣欣, 邹斌, 谭羽桐, 严晋跃

期刊论文

Glycosylation of dentin matrix protein 1 is critical for fracture healing via promoting chondrogenesis

Hui Xue, Dike Tao, Yuteng Weng, Qiqi Fan, Shuang Zhou, Ruilin Zhang, Han Zhang, Rui Yue, Xiaogang Wang, Zuolin Wang, Yao Sun

期刊论文

Role of salivary matrix metalloproteinase-8 (MMP-8) in chronic periodontitis diagnosis

null

期刊论文