Polar-coordinate line-projection light-curing continuous 3D printing for tubular structures

3D printing techniques offer an effective method in fabricating complex radially multi-material structures.However,it is challenging for complex and delicate radially multi-material model geometries without supporting structures,such as tissue vessels and tubular graft,among others.In this work,we tackle these challenges by developing a polar digital light processing technique which uses a rod as the printing platform.The 3D model fabrication is accomplished through line projection.The rotation and translation of the rod are synchronized to project and illuminate the photosensitive material volume.By controlling the distance between the rod and the printing window,we achieved the printing of tubular structures with a minimum wall thickness as thin as 50 micrometers.By controlling the width of fine slits at the printing window,we achieved the printing of structures with a minimum feature size of 10 micrometers.Our process accomplished the fabrication of thin-walled tubular graft structure with a thickness of only 100 micrometers and lengths of several centimeters within a timeframe of just 100 s.Additionally,it enables the printing of axial multi-material structures,thereby achieving adjustable mechanical strength.This method is conducive to rapid customization of tubular grafts and the manufacturing of tubular components in fields such as dentistry,aerospace,and more.

Experimental Study on Full-Surface Buckling of Variable Curvature Cylindrical Shell Using Multi-camera 3D-DIC System

To achieve full-surface strain measurement of variable curvature objects,a 360°3D digital image correlation(DIC)system is proposed.The measurement system consists of four double-camera systems,which capture the object’s entire surface from multiple angles,enabling comprehensive full-surface measurement.To increase the stitching quality,a hierarchical coordinate matching method is proposed.Initially,a 3D rigid body calibration auxiliary block is employed to track motion trajectory,which enables preliminary matching of four 3D-DIC sub-systems.Subsequently,secondary precise matching is performed based on feature points on the test specimen’s surface.Through the hierarchical coordinate matching method,the local 3D coordinate systems of each double-camera system are unified into a global coordinate system,achieving 3D surface reconstruction of the variable curvature cylindrical shell,and error analysis is conducted on the results.Furthermore,axial compression buckling experiment is conducted to measure the displacement and strain fields on the cylindrical shell’s surface.The experimental results are compared with the finite element analysis,validating the accuracy and effectiveness of the proposed multi-camera 3D-DIC measuring system.

3D object reconstruction by point coordinates of 2D line drawings

It is a research subject in computer vision to 3D reconstruction of an object represented by a single 2D line drawing. Previous works on 3D reconstruction from 2D line drawings focus on objects with lines, plane, view, and so on. This paper mainly studies the 3D reconstruction from 2D line drawings. Besides, a new approach is proposed： it is that for the research of the point coordinates of 2D line drawings, so as to achieve the object reconstruction by the reconstruction of point coordinates. The reconstruction process includes： （1） the collection of point coordinates （X,Y） of 2D line drawings; （2） the derivation of mathematical formula about the reconstruction of the point of 2D line drawings, and calculating the corresponding point of the 3D coordinates; （3） the regeneration of 3D graphics with 3D points; （4） analyze error by the proportional of parallel of axonometric projection, in order to prove the accuracy of the method.

THEORETICAL ANALYSIS OF COORDINATES MEASUREMENT BY FLEXIBLE 3D MEASURING SYSTEM

The system mathematical model of flexible 3D measuring system is built by theoretical analysis, and the theoretical formula for measuring space point coordinate is also derived. Frog-jumping based coordinate transform method is put forward in order to solve measuring problem for large size parts. The frog-jumping method is discussed, and the coordinate transform mathematical model is method of the space point coordinate compared to original value, and an advanced method is provided, Form the space point coordinate transform formula can derive the calculation measuring method for measuring large size parts.

An Algorithm for Finding Internal Faces Based on the 3D Coordinates

This paper presents a direct method to find the internal faces. It uses four sets of information： get the coordinates of each point on the 3D composite objects; （~）based on the 3D coordinates to calculate all the plane equation of two objects; （~）calculate all the intersecting lines of the two objects and exclude the intersecting lines which are not within the scope of the plane;finding the internal face, the remaining intersecting lines formed the plane is the internal face of the two objects. We proposed a new algorithm for finding internal faces. This algorithm could be adapted to any regular composite objects .The algorithm works well for finding internal faces.

A complete solution of an improved universal 3D coordinate similarity transformation model

When linearizing three-dimensional(3 D)coordinate similarity transformation model with large rotations,we usually encounter the ill-posed normal matrix which may aggravate the instability of solutions.To alleviate the problem,a series of conversions are contributed to the 3 D coordinate similarity transformation model in this paper.We deduced a complete solution for the 3 D coordinate similarity transformation at any rotation with the nonlinear adjustment methodology,which involves the errors of the common and the non-common points.Furthermore,as the large condition number of the normal matrix resulted in an intractable form,we introduced the bary-centralization technique and a surrogate process for deterministic element of the normal matrix,and proved its benefit for alleviating the condition number.The experimental results show that our approach can obtain the smaller condition number to stabilize the convergence of the interested parameters.Especially,our approach can be implemented for considering the errors of the common and the non-common points,thus the accuracy of the transformed coordinates improves.

Hydrothermal Synthesis and Crystal Structure of One 3D Coordination Polymer of Cobalt(II) Achieved from 1,1′-Biphenyl-2,2′,6,6′-tetracarboxylic Acid Ligand

A new three-dimensional coordination polymer {[Co（BPTC）0.5（bix）]′（H2O）}n （1, H4BPTC = 1,1′-biphenyl-2,2′,6,6′-tetracarboxylic acid, bix = 1,3-bis（imidazol-l-ylmethyl）-benzene） has been synthesized by the hydrothermal method and characterized by IR, elemental analysis, and single-crystal X-ray analysis. The crystal is of orthorhombic, space group Pbcn with a = 13.2975（10）, b = 13.8424（12）, c = 22.6367（17） A, CoC22H19N4Os, Mr = 478.34, V = 4166.7（6） A3, Dc = 1.525 g/cm^3, F（000） = 1968,μ = 0.867 mm^-1, S = 1.023 and Z = 8. The final R = 0.0683 and wR = 0.1529 for 3655 observed reflections with I 〉 20（I）. In the title complex, the 2D Co-BPTC layer is formed through self-assembly of Co（II） ions and bridging BPTC4-ligands in a molar ratio of 2：1. The metal-organic lattice layers are further united together through the second bridging ligand bix to form a 3D metal-organic framework. The thermal stability of the title complex was studied by thermal gravimetric （TG） and differential thermal analysis （DTA）.

Hydrothermal Synthesis and Crystal Structure of a Cd^(2+) Supramolecular Coordination Complex{[Cd_2(HCAM)_2(H_2O)_4]·3.5H_2O}_n with a 3D Metal-organic Open Framework

A three-dimensional coordination polymer {[Cd2（HCAM）2（H2O）4].3.SH2O}n was synthesized by the hydrothermal reaction of H3CAM （H3CAM = 4-hydroxypyridine-2,6-dicerboxylic acid） and Cd（NO3）2·4H2O. The structure was characterized by elemental analysis, thermal gravimetric analysis, infrared spectroscopy and single-crystal X-ray diffraction. It crystallizes in triclinic, space group P1 with a = 9.4389（19）, b = 11.009（2）, c = 11.192（2） A, α = 87.87（3）, β= 74.63（3）, γ = 81.22（3）°, V= 1108.2（4） A3, Z = 2, Dc= 2.164 g/cm3,μ = 2.011 mm^-1, F（000） = 710, R = 0.0419 and wR = 0.1170. X-ray analysis reveals that the title compound adopts a one-dimensional staircase structure by carboxyl of H3CAM and water molecules, and it is further linked by hydrogen bonds to form a 3-D metal-organic open framework. The thermal gravimetric analysis displays that the framework exists stably below 300 ℃.

A Novel Gd Coordination Polymer Based on 2-(Pyridin-3-yl)-1H-imidazole-4,5-dicarboxylate: Synthesis, Structure and Dielectric Properties

A new Gd coordination polymer based on 2-（pyridin-3-yl）-lH-imidazole-4,5-dicar- boxylate, formulated as {[Gd2（HPyIDC）2（H2O）5]·（bpy）·（NO3）2·3H2O}n （1, bpy = 4,4＇-bipyridine） has been synthesized under hydrothermal conditions. The compound crystallizes in triclinic, space group Pi with a = 11.451（2）, b = 11.596（2）, c = 15.7333（3） A, β = 79.47（3）°, Z = 2, V= 1948.6（7） A^3, C30H34Gd2N10O22, Dc = 2.047 g/cm^3, Mr= 1201.17, 2（MoKa） = 0.71073 A,μ = 3.477 mml, F（000） = 1176, the final R = 0.0554 and wR = 0.1181. Polymer 1 is a 2D network built up from 4-connected HPylDC2- anion and 4-connected Gd ions. Dielectric constant of complex 1 was measured at different frequencies with temperature variation.

A Novel Three-dimensional Mn(Ⅱ) Coordination Polymer Constructed from Biphenyl-3,3',5,5'-tetracarboxylic Acid and Water

The title Mn（Ⅱ） coordination polymer,poly{[heptaaqua-（μ4-bi-phenyl-3,3？,5,5？-tetracarboxylate）-bimanganese（Ⅱ）] pentahydrate},[Mn_2（bpta）（H_2O）_7]_n·5n H_2O（I）,is crystallized from a mixture of biphenyl-3,3？,5,5？-tetracarboxylic acid（H_4bpta） and MnCl_2·4H_2O in waterethanol under room temperature. Its asymmetric unit consists of one and two halves of crystallographically independent Mn（Ⅱ） cations,one fully deprotonated H4 bpta ligand,seven coordinated water molecules and five solvent water as guest molecules. In I,each Mn（Ⅱ） atom is octahedrally coordinated by six oxygen atoms from bpta^（4-） anions and coordinated water molecules. In the Mn（Ⅱ） cations,one half Mn（Ⅱ） ion of them located at a 2-fold axis generating a trinuclear [Mn_3（H_2O）_2（RCOO）_2] linker by μ1,1-O（water） and μ1,3-O,O？（carboxylate） bridges and another half Mn（Ⅱ） ion with an inversion is a mononuclear linker. These neighbouring trinuclear and mononuclear Mn（Ⅱ） cations are linked together by biphenyl-3,3？,5,5？-tetracarboxylates to form a three-dimensional framework with a（42.84） topology of a（4,4）-connected net,in which the positions of the trinuclear [Mn_3（H_2O）_2（R-COO）_2] linker as a 4-connector linking four bpta^（4-） ligands in I reproduce an eagle-shaped arrangement. The polymeric structure exhibits a water channel with an accessible void of 797.1 ？~3,amounting to 15.7% of the total unit-cell volume. Each of the cavities in the network is occupied by solvent water molecules.

Three-dimensional stability calculation method for high and large composite slopes formed by mining stope and inner dump in adjacent open pits

The 2D limit equilibrium method is widely used for slope stability analysis.However,with the advancement of dump engineering,composite slopes often exhibit significant 3D mechanical effects.Consequently,it is of significant importance to develop an effective 3D stability calculation method for composite slopes to enhance the design and stability control of open-pit slope engineering.Using the composite slope formed by the mining stope and inner dump in Baiyinhua No.1 and No.2 open-pit coal mine as a case study,this research investigates the failure mode of composite slopes and establishes spatial shape equations for the sliding mass.By integrating the shear resistance and sliding force of each row of microstrip columns onto the bottom surface of the strip corresponding to the main sliding surface,a novel 2D equivalent physical and mechanical parameters analysis method for the strips on the main sliding surface of 3D sliding masses is proposed.Subsequently,a comprehensive 3D stability calculation method for composite slopes is developed,and the quantitative relationship between the coordinated development distance and its 3D stability coefficients is examined.The analysis reveals that the failure mode of the composite slope is characterized by cutting-bedding sliding,with the arc serving as the side interface and the weak layer as the bottom interface,while the destabilization mechanism primarily involves shear failure.The spatial form equation of the sliding mass comprises an ellipsoid and weak plane equation.The analysis revealed that when the coordinated development distance is 1500 m,the error rate between the 3D stability calculation result and the 2D stability calculation result of the composite slope is less than 8%,thereby verifying the proposed analytical method of equivalent physical and mechanical parameters and the 3D stability calculation method for composite slopes.Furthermore,the3D stability coefficient of the composite slope exhibits an exponential correlation with the coordinated development distance,with the coefficient gradually decreasing as the coordinated development distance increases.These findings provide a theoretical guideline for designing similar slope shape parameters and conducting stability analysis.

Influence of Adoptment of Geocentric 3D Coordinate System on Chinese Existent Maps

If a geocentric 3D coordinate system is adopted in China to replace 2D non-geocentric coordinate system, the coordinates of the surface points will be changed accordingly. The influences on the current maps of China, especially the topographic maps, are discussed due to the replacement of the coordinate systems. Taking the replacement of Xi’an 80 coordinate system by GRS80 for a numerical example, this paper analyzes the changes of latitude, longitude, Gauss plane coordinates of the surface points, as well as the orientation and the length changes between the points on the map, including the changes of map border lines and sheet corner points.

Synthesis and Crystal Structure of a 2D Sm(Ⅲ) Coordination Polymer: {[Sm_2L_3(H_2O)_4]·(4,4?-bpy)·3H_2O}_n

A new compound, {[Sm^2L3（H2O）4]·（4,4＇-bpy）·3H2O}n（1, H2 L = 5-（3-pyridyl methoxy） isophthalic acid, 4,4＇-bpy = 4,4A-dipyridyl）, has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction. It crystallizes in triclinic, space group P1 with a = 11.266（2）, b = 15.530（3）, c = 16.711（3） A, α = 112.803（3）, β = 90.526（1）, γ = 94.006（3）°, V = 2686.6（9） A3, Z = 2, Dc = 1.727 g/cm^3, μ = 2.251 mm-1, F（000） = 1392, S = 0.999, the final R = 0.0296 and wR = 0.1058. In the title compound, two crystallographically independent Sm^3＋ cations are bridged by the carboxyl group of L2- ligands to form two different {Sm^2} binuclear subunits which are further connected by two distinct L2- ligands to shape a 1D chain, and such 1D chains are linked up to generate a 2D coordination polymer by another crystallographically unique L2- ligand. The thermogravimetric analysis and luminescent property of the title compound were also investigated.

Development of Flexible Spherical Actuator with 3D Coordinate Measuring Device

Rehabilitation devices help to recover the physical abilities of patients. This study aims to develop a portable rehabilitation device that is safe to use when?patients are holding it by hands. In a previous study, to realize a home rehabilitation device, a flexible spherical actuator that can provide motion to patients was developed. In this study, to measure the relative position between both handling stages, a 3D coordinate measuring device using three wire-type linear potentiometers and an embedded controller was proposed and tested. In this paper, the spherical actuator with built-in 3D coordinate measuring device is described. The measuring method and experimental results obtained are also presented. The tracking position control of the actuator using the measuring device was carried out. As a result, the position of the handling stages can be successfully controlled using the feedback signal from the tested?measuring device.

Polarization Projection for 3D Geometry-Based Stochastic Channel Model

Comprehensive radiation characteristics of polarized antenna are crucial in creating practical channel coefficients for next generation wireless communication system designs.Being currently supported within3 D geometry-based stochastic channel models(GSCM),field patterns are technically obtained by chamber measurement(or by its best fitting).However,in some channel related performance analysis scenarios,design insight can be crystallized better by starting the derivations with theoretical co-polarization and cross-polarization components.Specifically,these two components are mathematically linked with field patterns through the proposed polarization projection algorithm.In this manuscript,we focus on revealing the transformation criterion of polarization states between the antenna plane and the propagation plane.In practice,it makes retrieving the field patterns by electromagnetic computation possible.Meanwhile,the impact imposed by distinct antenna orientations is geometrically illustrated and consequently incorporated into the proposed algorithm.This will further facilitate flexible performance evaluation of related radio transmission technologies.Our conclusions are verified by the closed-form expression of the dipole field pattern(via an analytical approach) and by chamber measurement results.Moreover,we find that its 2D degenerative case is aligned with the definitions in 3^(rd) generation partnership project(3GPP)technical report 25.996.The most obvious benefit of the proposed algorithm is to significantly reduce the cost on generating channel coefficients in GSCM simulation.

One New 3D Pillared-layer Ag(Ⅰ)-Coordination Framework Based on a Unique 1D Ag2O2 Ribbon： Synthesis,Crystal Structure and Luminescent Properties

A new 3D Ag（I） coordination polymer {[Ag（AZDB）（0.5）（bpe）（0.5）]·H2O}n（1） has been papared by azobenzene-3,3？-dicarboxylicate（H2AZDB）, 1,2-bis（4-pyridyl）ethylene（bpe） and silver salts via hydrothermal method. The compound was fully characterized by single-crystal X-ray diffraction, elemental analyses, infrared spectrum（IR）, powder X-ray diffraction（PXRD） and thermogravimetric analysis（TGA）. The strucrural analysis indicate that compound 1 shows a 3D pillared-layer framework constructed from a unique 1D Ag2O2 ribbon and pyridyl/carboxylicate mixed system, which features a 2-nodal（4, 6）-connected fsc net with a（4^4·6^10·8）（4^4·6^2） topology.Moreover, the photoluminescent properties have also been discussed.

Ghrelin受体拮抗剂(D-Lys^(3))-GHRP-6减轻肥胖小鼠的脂肪炎症和氧化应激

目的探讨Ghrelin受体拮抗剂(D-Lys3)-GHRP-6对高脂饮食(HFD)诱导的肥胖小鼠的脂肪炎症和氧化应激的改善作用及机制。方法4周龄雄性C57BL/6J小鼠随机分为常规饮食(RD)、高脂饮食(HFD)和HFD+(D-Lys3)-GHRP-6组。饲养16周后分析各组小鼠的体质量、体脂率和体脂成分,收集各组小鼠的血液和脂肪组织。酶联免疫吸附法检测小鼠单核细胞趋化蛋白1(MCP-1)、白细胞介素(IL)-6、肿瘤坏死因子-α(TNF-α)和IL-10。HE染色评估脂肪细胞直径及脂滴水平。免疫荧光染色及流式细胞术分析脂肪组织血管基质成分(SVF)巨噬细胞的数量及表型。检测各组血清中总超氧化物歧化酶(SOD)、丙二醛(MDA)、过氧化氢酶(CAT)、黄嘌呤氧化酶(XO)、谷胱甘肽过氧化物酶(GPx)、黄嘌呤脱氢酶(XDH)的活性。结果HFD组小鼠体质量、体脂率、附睾白色脂肪组织(eWAT)、皮下白色脂肪组织(sWAT)、肩胛间脂肪组织(iBAT)及脂肪细胞直径、iBAT脂滴水平均较RD组显著升高(P<0.05);但在HFD+(D-Lys3)-GHRP-6组上述指标较HFD组均有明显下降(P<0.05)。与HFD组相比,HFD+(D-Lys3)-GHRP-6组血清IL-6、TNF-α、MCP-1及MDA、XO和XDH活性均明显下降,而IL-10及SOD、CAT和GPx活性均升高(P<0.05);并且e WAT组织冠状结构(CLS)数、SVF中巨噬细胞总数、巨噬细胞M1表型下降而M2表型升高(P<0.05)。结论(DLys3)-GHRP-6可能通过抑制促炎性巨噬细胞募集并加速其M1表型向M2表型转换和维持氧化应激平衡来缓解HFD诱导的肥胖和脂肪炎症。

3D显示技术的原理及应用

介绍了常见的3D显示技术的基本原理,对各种3D技术的优缺点进行了阐述,对3D显示技术目前的普及状况和应用领域作了详细说明。

基于LADRC的3D舞台威亚协调同步控制方法

针对机电参数摄动、钢绳弹性延伸及负载变化等对3D威亚系统造成的影响,根据"抗扰范式"建模理念,提出了一种基于线性自抗扰控制(LADRC)的3D舞台威亚协调同步控制策略,分别对3D舞台威亚系统的控制结构、控制器设计以及协调同步算法进行了研究.首先从威亚系统的单机LADRC设计入手,并进行相关稳定性分析;然后融合并联硬同步方法设计了适宜的软协调算法,进而实现了3D威亚系统的协调同步运行.仿真结果表明,所提出的控制策略,对于舞台空间内预设的无论是常规或非常规复杂姿态曲线,即使存在内外部不确定性"总扰",均能使3D威亚有着良好的轨迹拟合效果及协调同步性能,尤其是软协调同步算法中离线与在线的结合,为3D舞台威亚的工程应用提供了实施便利.

Construction of one-dimensional hierarchical MoS_(2)/Ni_(3)S_(2) composites with enhanced interfacial polarization and improved wideband microwave absorption

The construction of one-dimensional(1D)sulfides has attracted extensive attention for improving mi-crowave absorption(MA)performance owing to the anisotropic conductive networks.However,the syn-thesis of conductive 1D hierarchical materials with unique interfacial polarization and excellent MA prop-erties remains challenging.In this study,cable-like MoS_(2)/Ni_(3)S_(2) was synthesized by a one-step hydrother-mal strategy.The complex permittivity of the binary composites could be improved by tuning the thick-ness of the MoS_(2) coating.Importantly,the construction of heterogeneous contacts by MoS_(2) and Ni_(3)S_(2) contributed to enhanced polarization loss,and the charge distribution was validated by electron holog-raphy.The wide efficient absorption bandwidth can reach above 4.8 GHz at a thin thickness.These new discoveries shed light on novel structures for 1D sulfide materials and the design of functional core-shell composites for microwave absorption.