scholarly journals Study on Three-Dimensional Digital Expression and Robot Bending Method of Orthodontic Archwire

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Jingang Jiang ◽  
Xuefeng Ma ◽  
Yongde Zhang ◽  
Biao Huo ◽  
Yi Liu
Keyword(s):  
Dimensional Space ◽  
Control Point ◽  
Three Dimensional ◽  
Treatment Method ◽  
Planning Method ◽  
Oral Disease ◽  
Simple Modification ◽  
Digital Expression ◽  
Low Efficiency ◽  
Orthodontic Archwires

Malocclusion is the third largest oral disease in the world. At present, the most effective treatment method for malocclusion is the fixed orthodontic technique based on orthodontic archwires. Robotic archwire bending can overcome the shortcomings of manual bending such as low efficiency and low precision. The three-dimensional digital expression and robot bending method of orthodontic archwire are studied to realize the orthodontic archwire bending using a robot. Tooth is identified by the doctors’ common method. The shape, position, and constraint relationship of orthodontic archwire in three-dimensional space are expressed by the Bessel curve. The bending of the archwire curve is realized by transmitting the archwire curve into the alternative lines. The planning method of forming points and the spatial angle planning method are proposed. The archwire bending experiment is carried out with the maxillary information of a patient. The error rate of the experimental and ideal values is between 2.94% and 6.74%. It can meet the physician’s basic requirements after simple modification. Therefore, it can be considered that the method of using discrete Bessel curve to carry out the control point planning and angle planning is suitable for the orthodontic archwire-bending robot system, which has certain feasibility and practicability in clinical treatment.

scholarly journals Adaptive Honeycomb Based on Additive Manufacturing: Research on Rapid Generation Algorithm, Manufacturing Process, and Mechanical Characteristics

2021 ◽  
Author(s):  
Bo Qian ◽  
Hongri Fan
Keyword(s):  
Additive Manufacturing ◽  
Mechanical Performance ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Absorption Efficiency ◽  
Generation Algorithm ◽  
Steel Material ◽  
Rapid Generation ◽  
Low Efficiency ◽  
Critical Yield

Abstract In order to solve the problems of low efficiency and complex process in the current generation algorithm and process verification of hexagonal honeycomb structures for complex spatial shapes and arbitrarily curved surfaces, this paper proposes an adaptive hexagonal grid calculation method based on the intracellular splitting iteration method for the first time. This method can better adapt to the complex spatial shape and arbitrary curved surface structure in the three-dimensional space, and it can also achieve the purpose of enhancing the mechanical performance while maintaining the lightweight structure. According to the principle of the above algorithm, different structural models including honeycomb cells are calculated and generated. 316L Stainless Steel material and Selective Laser Melting additive manufacturing processes are also used for printing actual samples. The printed samples are mechanically compressed. According to the results of the compression curve, the critical yield force of the honeycomb grid parts with iteration is higher than that of the homogeneous honeycomb grid parts, and the value is basically greater than 30%-40%. Finally, the energy absorption efficiency can be increased by more than 20% according to the compression characteristics of the adaptive iterative honeycomb analyzed.

scholarly journals Springback mechanism analysis and experimentation of orthodontic archwire bending considering slip warping phenomenon

2018 ◽  
Vol 15 (3) ◽  
pp. 172988141877422 ◽  
Author(s):  
Jiang Jin-gang ◽  
Ma Xue-Feng ◽  
Zhang Yong-De ◽  
Liu Yi ◽  
Huo Biao
Keyword(s):  
Orthodontic Treatment ◽  
Treatment Method ◽  
Oral Disease ◽  
Mechanism Analysis ◽  
Fixed Appliance ◽  
Mechanism Model ◽  
Bending Process ◽  
Bending Radius ◽  
Orthodontic Archwires ◽  
Two Stages

Malocclusion is a common oral disease. Fixed appliance technology is the most common and effective malocclusion orthodontic treatment method, and the key step of fixed appliance technology is the bending of orthodontic archwire. Because the slip warping phenomenon exists in the process of orthodontic archwire bending, it is difficult to realize rapid and accurate bending of the customized orthodontic archwires. A bending springback mechanism model considering the slip warping of the archwire in the process of bending is established. The influence of the slip warping phenomenon of the archwire between the fixed mold and the rotation mold is considered in the analysis of the springback mechanism. The bending process of archwire is divided into two stages: elastic deformation and plastic deformation, based on the variety of the bending radius in the bending process. A springback mechanism model of the orthodontic archwire is established. The springback mechanism model of the orthodontic archwire is analyzed and compensated based on the characteristics of the robot structure. An archwire bending experiment is carried out to verify the correctness of the springback mechanism model of the orthodontic archwire.

scholarly journals NiFe LDH@Super P Nanocomposite as an Efficient Electrocatalyst for Oxygen Evolution Reaction

2021 ◽  
Vol 257 ◽  
pp. 01029
Author(s):  
Li Ren ◽  
Jiaqi Wang ◽  
Bing Xue ◽  
Fangfei Li
Keyword(s):  
Precious Metal ◽  
Dimensional Space ◽  
Research Work ◽  
Three Dimensional ◽  
Treatment Method ◽  
Alkaline Media ◽  
Simple Method ◽  
Composite Effect ◽  
Highly Active ◽  
Full Contact

NiFe LDH (Layered Double Hydroxide) is a promising electrocatalyst for oxygen release reaction (OER), which is currently receiving more and more attention. Here, we propose a simple method to enhance the OER activity of NiFe LDH supported on Super P. The NiFe LDH@Super P catalyst with a nanoflower nanostructure was successfully synthesized via pre-hydrothermal treatment method, which ensures the normal nucleation process of the highly active NiFe LDH precursor and significantly promote the full contact of NiFe LDH and Super P in the three-dimensional space. The as synthesized NiFe LDH@Super P-2h sample exhibited excellent OER performances in alkaline media, and the overpotential is only 260 mV at a current density of 10 mA · cm-2. The outstanding OER electrocatalytic reaction performance is attributed to the unique three-dimensional nanoflower structure and excellent composite effect with Super P, which provides more specific surface areas and enables efficient transfer of electrons between them. This research work provides a simple and effective method for developing non-precious metal-based OER catalysts to replace expensive precious metal catalysts.

scholarly journals Continuous Visible Query for Three-Dimensional Objects in Spatial Databases

2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
Yongshan Liu ◽  
Dehan Kong
Keyword(s):  
Spatial Databases ◽  
Dimensional Space ◽  
Spatial Database ◽  
Control Point ◽  
Three Dimensional ◽  
Range Query ◽  
Visible Range ◽  
Vertical Projection ◽  
Three Dimensional Objects ◽  
Projection Angle

Present research of visible query focuses on points and segments in two-dimensional space, while disfigurements occur during processing of visible query in three-dimensional space. In this paper, Continuous Visible Range Query Based on Control Point (CVRQ-CP) is proposed to solve the visible query in a 3D spatial database. Firstly, the horizontal angle (HA) and Vertical Projection Angle (VPA) for 3D objects in a spatial database were used in the visibility testing method. The HA and VPA in the processing of the continuous visible query created visibility changes, defining and confirming the control point. Finally, the algorithm of Continuous Visible Range Query Based on Control Point (CVRQ-CP) was proposed. Verified by experiments, the CVRQ-CP algorithm correctly deals with the visible query of 3D spatial objects. The CVRQ-CP algorithm has better superior accuracy over present visible queries in 3D spatial databases.

Three Dimensional structure and organization of diploid chromosomes by optical section microscopy

1987 ◽  
Vol 45 ◽  
pp. 633-635
Author(s):  
David A. Agard ◽  
Yasushi Hiraoka ◽  
John W. Sedat
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Developmental State ◽  
Mitotic Cell ◽  
Biological Properties ◽  
Dimensional Structure ◽  
Specific Gene ◽  
Three Dimensional Structure ◽  
Complementary Techniques ◽  
Dynamic Structures

In an effort to understand the complex relationship between structure and biological function within the nucleus, we have embarked on a program to examine the three-dimensional structure and organization of Drosophila melanogaster embryonic chromosomes. Our overall goal is to determine how DNA and proteins are organized into complex and highly dynamic structures (chromosomes) and how these chromosomes are arranged in three dimensional space within the cell nucleus. Futher, we hope to be able to correlate structual data with such fundamental biological properties as stage in the mitotic cell cycle, developmental state and transcription at specific gene loci.Towards this end, we have been developing methodologies for the three-dimensional analysis of non-crystalline biological specimens using optical and electron microscopy. We feel that the combination of these two complementary techniques allows an unprecedented look at the structural organization of cellular components ranging in size from 100A to 100 microns.

Diffraction contrast of dislocations in icosahedral quasicrystals

1990 ◽  
Vol 48 (4) ◽  
pp. 454-455
Author(s):  
K. Urban ◽  
Z. Zhang ◽  
M. Wollgarten ◽  
D. Gratias
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Complete Characterization ◽  
Extinction Condition ◽  
Burgers Vector ◽  
Diffraction Contrast ◽  
Lattice Geometry ◽  
Reference Space ◽  
Icosahedral Quasicrystals ◽  
The One

Recently dislocations have been observed by electron microscopy in the icosahedral quasicrystalline (IQ) phase of Al65Cu20Fe15. These dislocations exhibit diffraction contrast similar to that known for dislocations in conventional crystals. The contrast becomes extinct for certain diffraction vectors g. In the following the basis of electron diffraction contrast of dislocations in the IQ phase is described. Taking account of the six-dimensional nature of the Burgers vector a “strong” and a “weak” extinction condition are found.Dislocations in quasicrystals canot be described on the basis of simple shear or insertion of a lattice plane only. In order to achieve a complete characterization of these dislocations it is advantageous to make use of the one to one correspondence of the lattice geometry in our three-dimensional space (R3) and that in the six-dimensional reference space (R6) where full periodicity is recovered . Therefore the contrast extinction condition has to be written as gpbp + gobo = 0 (1). The diffraction vector g and the Burgers vector b decompose into two vectors gp, bp and go, bo in, respectively, the physical and the orthogonal three-dimensional sub-spaces of R6.

Flavin radicals, conformational sampling and robust design principles in interprotein electron transfer: the trimethylamine dehydrogenase-electron-transferring flavoprotein complex

2004 ◽  
Vol 71 ◽  
pp. 1-14
Author(s):  
David Leys ◽  
Jaswir Basran ◽  
François Talfournier ◽  
Kamaldeep K. Chohan ◽  
Andrew W. Munro ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Kinetic Studies ◽  
Molecular Assembly ◽  
Conformational Sampling ◽  
Trimethylamine Dehydrogenase ◽  
Key Residues ◽  
Electron Transferring Flavoprotein ◽  
Electron Transfer Complex

TMADH (trimethylamine dehydrogenase) is a complex iron-sulphur flavoprotein that forms a soluble electron-transfer complex with ETF (electron-transferring flavoprotein). The mechanism of electron transfer between TMADH and ETF has been studied using stopped-flow kinetic and mutagenesis methods, and more recently by X-ray crystallography. Potentiometric methods have also been used to identify key residues involved in the stabilization of the flavin radical semiquinone species in ETF. These studies have demonstrated a key role for 'conformational sampling' in the electron-transfer complex, facilitated by two-site contact of ETF with TMADH. Exploration of three-dimensional space in the complex allows the FAD of ETF to find conformations compatible with enhanced electronic coupling with the 4Fe-4S centre of TMADH. This mechanism of electron transfer provides for a more robust and accessible design principle for interprotein electron transfer compared with simpler models that invoke the collision of redox partners followed by electron transfer. The structure of the TMADH-ETF complex confirms the role of key residues in electron transfer and molecular assembly, originally suggested from detailed kinetic studies in wild-type and mutant complexes, and from molecular modelling.

Topics in Quaternion Linear Algebra

2014 ◽  
Author(s):  
Leiba Rodman
Keyword(s):  
Linear Algebra ◽  
Complex Analysis ◽  
Dimensional Space ◽  
Applied Mathematics ◽  
Three Dimensional ◽  
Number System ◽  
Graduate Course ◽  
Open Problems ◽  
Unpublished Research ◽  
Reference Tool

Quaternions are a number system that has become increasingly useful for representing the rotations of objects in three-dimensional space and has important applications in theoretical and applied mathematics, physics, computer science, and engineering. This is the first book to provide a systematic, accessible, and self-contained exposition of quaternion linear algebra. It features previously unpublished research results with complete proofs and many open problems at various levels, as well as more than 200 exercises to facilitate use by students and instructors. Applications presented in the book include numerical ranges, invariant semidefinite subspaces, differential equations with symmetries, and matrix equations. Designed for researchers and students across a variety of disciplines, the book can be read by anyone with a background in linear algebra, rudimentary complex analysis, and some multivariable calculus. Instructors will find it useful as a complementary text for undergraduate linear algebra courses or as a basis for a graduate course in linear algebra. The open problems can serve as research projects for undergraduates, topics for graduate students, or problems to be tackled by professional research mathematicians. The book is also an invaluable reference tool for researchers in fields where techniques based on quaternion analysis are used.

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