Quasi-static 3D structure of graphene ripple measured using aberration-corrected TEM

Nanoscale ◽  
2021 ◽  
Author(s):  
Yuhiro Segawa ◽  
Kenji Yamazaki ◽  
Jun Yamasaki ◽  
Kazutoshi Gohara

Free-standing graphene has a three-dimensional (3D) structure, called a ripple, rather than a perfect two-dimensional (2D) crystal. Since theoretical calculations suggest that a ripple strongly influences various fundamental physicochemical properties...

2019 ◽  
Vol 75 (4) ◽  
pp. 443-450
Author(s):  
Guiying Zhu ◽  
Yang Lu ◽  
Guoxia Jin ◽  
Xuan Ji ◽  
Jianping Ma

Three new one- (1D) and two-dimensional (2D) CuII coordination polymers, namely poly[[bis{μ2-4-amino-3-(pyridin-2-yl)-5-[(pyridin-3-ylmethyl)sulfanyl]-1,2,4-triazole}copper(II)] bis(methanesulfonate) tetrahydrate], {[Cu(C13H12N5S)2](CH3SO3)2·4H2O} n (1), catena-poly[[copper(II)-bis{μ2-4-amino-3-(pyridin-2-yl)-5-[(pyridin-4-ylmethyl)sulfanyl]-1,2,4-triazole}] dinitrate methanol disolvate], {[Cu(C13H12N5S)2](NO3)2·2CH3OH} n (2), and catena-poly[[copper(II)-bis{μ2-4-amino-3-(pyridin-2-yl)-5-[(pyridin-4-ylmethyl)sulfanyl]-1,2,4-triazole}] bis(perchlorate) monohydrate], {[Cu(C13H12N5S)2](ClO4)2·H2O} n (3), were obtained from 4-amino-3-(pyridin-2-yl)-5-[(pyridin-3-ylmethyl)sulfanyl]-1,2,4-triazole with pyridin-3-yl terminal groups and from 4-amino-3-(pyridin-2-yl)-5-[(pyridin-4-ylmethyl)sulfanyl]-1,2,4-triazole with pyridin-4-yl terminal groups. Compound 1 displays a 2D net-like structure. The 2D layers are further linked through hydrogen bonds between methanesulfonate anions and amino groups on the framework and guest H2O molecules in the lattice to form a three-dimensional (3D) structure. Compound 2 and 3 exhibit 1D chain structures, in which the complicated hydrogen-bonding interactions play an important role in the formation of the 3D network. These experimental results indicate that the coordination orientation of the heteroatoms on the ligands has a great influence on the polymeric structures. Moreover, the selection of different counter-anions, together with the inclusion of different guest solvent molecules, would also have a great effect on the hydrogen-bonding systems in the crystal structures.


Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1089 ◽  
Author(s):  
Chenyu Wang ◽  
Bozhong Lin ◽  
Haopeng Zhu ◽  
Fei Bi ◽  
Shanshan Xiao ◽  
...  

Glucose-sensitive drug platforms are highly attractive in the field of self-regulated drug delivery. Drug carriers based on boronic acid (BA), especially phenylboronic acid (PBA), have been designed for glucose-sensitive self-regulated insulin delivery. The PBA-functionalized gels have attracted more interest in recent years. The cross-linked three-dimensional (3D) structure endows the glucose-sensitive gels with great physicochemical properties. The PBA-based platforms with cross-linked structures have found promising applications in self-regulated drug delivery systems. This article summarizes some recent attempts at the developments of PBA-mediated glucose-sensitive gels for self-regulated drug delivery. The PBA-based glucose-sensitive gels, including hydrogels, microgels, and nanogels, are expected to significantly promote the development of smart self-regulated drug delivery systems for diabetes therapy.


2016 ◽  
Vol 69 (11) ◽  
pp. 1296 ◽  
Author(s):  
Ya-Ru Pan ◽  
Xiu-Mei Li ◽  
Jian-Ye Ji ◽  
Qing-Wei Wang

Two new complexes [Co(NIPH)(bimb)(H2O)]n (1) and [Ni(NIPH)(mbix)]n (2) (H2NIPH = 5-nitroisophthalic acid, bimb = 1,4-bis(imidazol-1-yl)butane, mbix = 1,3-bis(imidazol-1-ylmethyl)benzene) have been hydrothermally synthesised and structurally characterised by elemental analysis, IR spectroscopy, thermogravimetric analysis, UV spectroscopy, and single-crystal X-ray diffraction. Complex 1 exhibits a two-dimensional (2D) network, which was stabilised through O–H···O and C–H···O hydrogen-bonding interactions. Complex 2 shows a two-dimensional (2D) network structure, which was further extended into a three-dimensional supramolecular structure through C–H···O hydrogen bonds and π–π interactions. Moreover, we analysed the natural bond orbital (NBO) using the PBE0/LANL2DZ method in the Gaussian 03 program. The calculation results indicated the obvious covalent interactions between the coordinated atoms and the CoII or NiII ion.


2019 ◽  
Vol 24 (10) ◽  
pp. 3354-3377 ◽  
Author(s):  
Matko Ljulj ◽  
Josip Tambača

In this paper, we derive models for the interaction of a linearized three-dimensional elastic structure with a thin elastic layer of possibly different material attached to it. Rigorous derivation is performed by considering a thin three-dimensional layer and the asymptotics of the solution of the full remaining three-dimensional problem when the thickness [Formula: see text] of the thin layer tends to zero. Furthermore, the attached thin material is assumed to have the elasticity coefficients which are of order [Formula: see text], for [Formula: see text] with respect to the coefficients of the three-dimensional body. In the limit, five different models are obtained with respect to different choices of p, namely [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text]. Furthermore a three-dimensional–two-dimensional model is proposed that has the same asymptotics as the original three-dimensional problem. This is convenient for applications because one does not have to decide in advance which limit model to use.


Soft Matter ◽  
2020 ◽  
Vol 16 (33) ◽  
pp. 7739-7750
Author(s):  
Mingchao Liu ◽  
Lucie Domino ◽  
Dominic Vella

Transforming flat two-dimensional (2D) sheets into three-dimensional (3D) structures by a combination of careful cutting and applied loads is an emerging manufacturing paradigm; we study how to design the cut pattern to obtain a desired 3D structure.


Author(s):  
William E. Pedersen ◽  
Daniel N. Pope

This study presents the design and modeling of an integrated wind energy building. It is proposed that a building be constructed with an integral wind turbine that takes advantage of the funneling of wind from the building structure and the low pressure area above or leeward of the building. Computational Fluid Dynamics (CFD) was used to evaluate different building geometries and wind potentials. Preliminary investigations using two dimensional numerical modeling in both the horizontal and vertical planes are presented. Three dimensional analyses are also presented of promising geometries from the two dimensional preliminary results. While additional modeling efforts will be necessary to optimize this system, results indicate a significant improvement in performance over free standing turbines, allowing for utilization of wind power in geographic regions that have traditionally not been feasible.


2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Melanie Walker ◽  
Kelvin Jones ◽  
DaiQuan Noble ◽  
Marquavias Walker ◽  
Douglas L. Strout

Boron nitride is a material similar to carbon in its ability to adopt numerous molecular forms, including two-dimensional sheets and three-dimensional cages and nanotubes. Boron nitride single molecules, such as B12N12, have isomeric forms that include rings and sheets, as well as cage forms analogous and isoelectronic to the carbon fullerenes. Such cages tend to be composed of squares and hexagons to allow perfect alternation of boron and nitrogen atoms, which is possible because of the 1 : 1 ratio of boron-to-nitrogen atoms. What about molecules in which this 1 : 1 ratio does not apply? In the current study, theoretical calculations are carried out on molecules of B10N14 to determine energetically favorable isomers. Density functional theory is used in conjunction with Dunning basis sets. Cage, sheet, and ring isomers are considered. Energetic trends are calculated and discussed, in comparison to comparable studies on B12N12.


2021 ◽  
Author(s):  
Qin Ma ◽  
Tinghao Tong ◽  
Zhi Su

Two isomorphic rare-earth borate crystals, YZnB5O10 and GdZnB5O10, show three-dimensional structures constructed from two-dimensional {[B5O10]5−}n layers with the Y or Gd, and zinc ions filled in the interlayers, and exhibit DUV cut-off edges (<190 nm).


IUCrJ ◽  
2021 ◽  
Vol 8 (5) ◽  
Author(s):  
Uriel Vaknin ◽  
Dov Sherman ◽  
Semën Gorfman

Cleavage is the ability of single crystals to split easily along specifically oriented planes. This phenomenon is of great interest for materials' scientists. Acquiring the data regarding cleavage is essential for the understanding of brittle fracture, plasticity and strength, as well as for the prevention of catastrophic device failures. Unfortunately, theoretical calculations of cleavage energy are demanding and often unsuitable for high-throughput searches of cleavage planes in arbitrary crystal structures. A simplified geometrical approach (GALOCS = gaps locations in crystal structures) is suggested for predicting the most promising cleavage planes. GALOCS enumerates all the possible reticular lattice planes and calculates the plane-average electron density as a function of the position of the planes in the unit cell. The assessment of the cleavage ability of the planes is based on the width and depth of planar gaps in crystal structures, which appear when observing the planes lengthwise. The method is demonstrated on two-dimensional graphene and three-dimensional silicon, quartz and LiNbO3 structures. A summary of planar gaps in a few more inorganic crystal structures is also presented.


2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Dongping Deng ◽  
Yong Chen

Self-folding structures have unique capability such as reconfiguration during their usage. Such capability can be beneficial for a wide variety of applications including biomedical and electronics products. In this paper, a novel fabrication approach based on a three-dimensional (3D) printing process is presented for fabricating self-folding structures that can be actuated in a heating environment. The thermo-actuating structures that are designed and fabricated by our method are two-dimensional (2D) origami sheets, which have multiple printed layers. The middle layer of an origami sheet is a prestrained polystyrene film with large shrinkage ratios when heated. Both its top and bottom surfaces are covered with cured resin that is printed in designed shapes. A foldable hinge is achieved by constraining the shrinkage of the film on one side while allowing the shrinkage of the film on another side when the origami sheet is exposed to a heating environment. Heuristic models of hinge's folding angles are developed based on the related folding mechanism. A 2D origami sheet design and fabrication method is presented for a given 3D structure. Various experimental tests are performed to verify the self-folding performance of the designed and fabricated origami sheets. Techniques on improving folding angle control are also discussed with possible applications.


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