Geometric Method of Spatial Linkages Synthesis for Function Generation With Three Finite Positions

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Song Lin ◽  
Hanchao Wang ◽  
Jingshuai Liu ◽  
Yu Zhang

This paper presents a geometric method as a unified synthesis process of function generation for spatial linkages. The synthesis method utilizes the mapping relationship between spatial kinematic geometric model and two-plane projection system to transform the problem from spatial geometry to plane geometry. In this way, the synthesis process of mechanisms can be simplified through the corresponding transformation. Afterward, the line-guidance model is built up. Combining the kinematic inversion in two-plane projection system, this model can be used to realize the spatial linkages synthesis for function generation with three finite positions. Finally, revolute–sphere–sphere–revolute (RSSR) and revolute–sphere–sphere–prism (RSSP) mechanisms are offered to illustrate the application of this method.


2020 ◽  
Vol 12 (3) ◽  
Author(s):  
Song Lin ◽  
Hanchao Wang ◽  
Yu Zhang ◽  
Jingyu Jiang

Abstract In the dimension synthesis of the spatial linkages, the geometric characteristics of floating links in mechanisms reveal the geometric relationship between the motion task and the dimensions of the mechanisms. In order to establish the kinematic geometry rules corresponding to the motion of the floating link, this paper transforms the kinematic problems of geometric elements on the floating link into geometric problems and uses the geometric procedure to solve the spatial linkages synthesis problem with four given positions. In a previous work, we have extracted the kinematic geometry rules of a line with two and three positions. However, as the number of task positions increases, the kinematic characteristics representing the position transformation become more complicated. The method proposed in this paper extends the previous work to four given positions and builds up the geometric relationships among the kinematic rules for two, three, and four positions. The establishment of this geometric relationship is helpful to unify the synthesis procedure of synthesis problems with different number of positions. After that, the two-plane projection system and the transformation of projection are introduced to establish a procedural graphical synthesis method.



2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
M. A. El-Sheikh

The water soluble photoinitiator (PI) 4-(trimethyl ammonium methyl) benzophenone chloride is used for the first time in the synthesis of silver nanoparticles (AgNPs). A new green synthesis method involves using PI/UV system, carboxymethyl starch (CMS), silver nitrate, and water. A mechanism of the reduction of silver ions to AgNPs by PI/UV system as well as by the newly born aldehydic groups was proposed. The synthesis process was assessed by UV-vis spectra and TEM of AgNPs colloidal solution. The highest absorbance was obtained using CMS, PI and AgNO3concentrations of 10 g/L, 1 g/L, and 1 g/L, respectively; 40°C; 60 min; pH 7; and a material : liquor ratio 1 : 20. AgNPs so-obtained were stable in aqueous solution over a period of three weeks at room temperature (~25°C) and have round shape morphology. The sizes of synthesized AgNPs were in the range of 1–21 nm and the highest counts % of these particles were for particles of 6–10 and 1–3 nm, respectively.



2018 ◽  
Vol 281 ◽  
pp. 40-45
Author(s):  
Jie Guang Song ◽  
Lin Chen ◽  
Cai Liang Pang ◽  
Jia Zhang ◽  
Xian Zhong Wang ◽  
...  

YAG materials has a number of unique properties, the application is very extensive. In this paper, the superfine YAG powder materials were prepared by co-precipitation method and hydrothermal precipitation method. The influence of synthesis process on the morphology of the powder was investigated. The results showed that the precursor powder prepared via the co-precipitation method is mainly from amorphous to crystalline transition with the increasing calcination temperature, the precursor agglomeration is more serious, In the process of increasing the calcination temperature, the dispersibility of the roasted powder is greatly improved, which is favorable for the growth of the crystal grains, so that the particle size of the powder is gradually increased, the YAG precursor prepared by the co-precipitation method is transformed into YAG crystals, the phase transition occurs mainly between 900 and 1100°C. When the molar ratio of salt to alkali is Y3+: OH-=1: 8 via the hydrothermal reaction, the YAG particles with homogeneous morphology can be obtained. When the molar ratio of salt and alkali is increased continuously, the morphology of YAG particles is not obviously changed. The co-precipitation method is easy to control the particle size, the hydrothermal method is easy to control the particle morphology.



2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yunpeng Shang ◽  
Hui Gao ◽  
Lei Li ◽  
Chaoqun Ma ◽  
Jiao Gu ◽  
...  

Herein, we prepared the L-histidine- (His-) protected silver nanoclusters (Ag NCs) by the microwave synthesis method. The synthesis process was rapid, facile, and environmentally friendly. Under 356 nm excitation, the as-prepared Ag NCs exhibited the blue fluorescence, and the fluorescence emission peak was located at 440 nm. The Ag NCs could successfully detect trace copper (Cu2+) ions in the aqueous solution and the limit of detection (LOD) was as low as 0.6 pM. Interestingly, the Ag NCs showed a different pH-dependent selectivity for both Cu2+ and iron (Fe3+) ions with no responses to other heavy metal ions. Furthermore, the as-fabricated fluorescent sensing system was utilized to detect glutathione (GSH, the LOD was 0.8 nM) by using the “switch-on” fluorescence recovery of Ag NCs through adding glutathione (GSH) to the Cu2+-Ag NCs solution.



Author(s):  
Wen-Yi Lin

Many studies to find solutions for the optimum synthesis problems of linkage mechanisms for path, motion or function generation have appeared in the literature. However, their main focus has been on the development of optimization algorithms or synthesis methods without the handling of the defect problems or only with consideration of the same assembly mode. Hwang and Chen's pioneering work proposed a defect-free optimum synthesis method with constraint equations to eliminate order, circuit and branch defects for Stephenson III six-bar motion generators. However, their proposed constraint equations for the three types of defects are incomplete or not clear enough. In this discussion, we not only examine these faults but also offer the correct and complete constraints to eliminate the three types of defects.



Kybernetes ◽  
2002 ◽  
Vol 31 (9/10) ◽  
pp. 1274-1281 ◽  
Author(s):  
František Čapkovič

A new control synthesis method suitable for a special kind of discrete event dynamic systems (DEDS) is presented in this paper. The systems to be controlled are modelled by a special class of Petri nets (PN) named state machine (SM). The class is distinctive by the fact that each PN transition has only one input place and only one output place. Bipartite directed graphs (BDG) are utilized in the control synthesis process. Namely, PN in general are (from the structure point of view) the BDG. Both the state reachability tree and the corresponding control one are developed in the straight‐line procedure starting from the given initial state and directed to the desirable terminal one as well as in the backtracking procedure starting from the terminal state and directed to the initial one. After a suitable intersection of both the straight‐lined state reachability tree and the backtracking one the state trajectories of the system are obtained. After the intersection of both the straight‐lined control reachability tree and the backtracking one the control interferences corresponding to the state trajectories are obtained.



2012 ◽  
Vol 512-515 ◽  
pp. 2262-2266
Author(s):  
Rong Ming Zhang ◽  
Yue Wang ◽  
Wei Li ◽  
Hong Man Shan

2-hydroxyl-3-sulfonic acid sodium salt-propyl lacrylate was synthesized through the three-step process (sulfonation, ring-closing reaction, and esterification) by using epichlorohydrin as the starting material. The structure of oxiranemethane sulfonic acid sodium salt and end product 2-hydroxyl-3-sulfonic acid sodium salt-propyl lacrylate was identified by FTIR and Melting point. The influence factors of the synthesis process were studied. The optimal condition of the synthesis of ring-closing reaction and esterification was gained. Through the synthesis method, a corresponding synthesis of lauric acid, 14 acid, palmitic acid, 18 acid were gained. Then they were on the surface tension tests to determine the critical micelle concentration.



2021 ◽  
Vol 30 ◽  
pp. 263498332110389
Author(s):  
S Morkoç Karadeniz

A simple wet-chemical synthesis method was developed to fabricate Zinc oxide micro-rod clusters. The synthesis process involved the rapid dilution of a zinc-bearing alkaline solution at 150°C in a convection oven on indium tin oxide (ITO) substrates. The synthesis was carried out by immersing an unseeded ITO substrate in a mixture of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and hexamethylenetetramine ((CH2)6N4) aqueous solution. The obtained sample was annealed at 400°C for 2 h. The structural, morphological and optical properties of the synthesized ZnO microstructures were investigated by X-ray diffraction, scanning electron microscopy and ultraviolet-visible spectroscopy, respectively. The ZnO rod clusters are hexagonal phase of the wurtzite structure. The crystal grain sizes of the films were found to be 72.6, 84.3 and 66.3 nm for the (100), (002) and (101) crystal planes, respectively. The optical bandgap of the ZnO was determined to be 3.147 eV.



2020 ◽  
Author(s):  
Yilun Sun ◽  
Yuqing Liu ◽  
Nandi Zhou ◽  
Tim C. Lueth

Soft robotic grippers are widely used in different industrial applications since they show great advantages in the adaptable grasping of objects with irregular shapes. However, as many soft grippers have a monolithic structure and gain their motion from the elastic deformation, it is difficult to use the conventional rigid-body mechanism theory to synthesize the shape of the soft grippers. To cope with this problem, the topology optimization is frequently employed as synthesis method since it can achieve automatic design of continuum-structure mechanisms. In this paper, we propose a novel 3D topology optimization framework in MATLAB to achieve automatic design of soft robotic grippers. Two design examples are also presented to illustrate the automatic synthesis process. Experimental tests have shown that the 3D topology optimized grippers in the example can successfully grasp objects with different shapes. In future work, the proposed framework can be further developed to synthesize soft robotic grippers with different actuation mechanisms and task-specific grasping behaviors.



2021 ◽  
Author(s):  
Mahdieh Yahyazadehfar ◽  
Enayatollah Sheikhhosseini ◽  
Sayed Ali Ahmadi ◽  
Dadkhoda Ghazanfari

Abstract In this study, controllable and optimal microwave irradiation has been used to synthesize the novel nanostructures of Bi2O3 under environmental conditions. The final products had a thermal stability of 210 °C, an average particle size distribution of 85 nm, and surface area of 783 m2/g. The high thermodynamic stability of Bi2O3 nanostructures were confirmed by TG and DSC analyses. The nanostructure nature of compounds, most importantly, the use of effective, cost effective and rapid synthesis route of microwave have created significant physiochemical properties in the Bi2O3 products. These unexpected properties have made the possibility of potentials application of these products in various fields, especially in nanocatalyst applications. It is well-documented that, as Lewis acid, bismuth nanocatalyst exhibits a great catalytic activity for the green synthesis of some bio-active barbituric acid derivatives using precursors with electron-donating or –withdrawing nature in high yields (80-98%). After incorporating this catalyst into the aqueous media, all the reactions were completed within 2-3 min at room temperature. The main advantages of this method are practical facility, the availability of starting materials, and low costs besides the catalyst reusability. Additionally, the catalyst synthesis process may be carried in the aqueous media during a short period with medium to high yields. The obtained results have opened a new window for development of a novel nanocatalyst with practical application.



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