Triangular Pyramid Structure Research Articles

Construction of a Novel Stable Electron Transfer Protein for the Creation of Artificial Direct Electron Transfer Enzymes

In recent years, wearable sensors aiming to enable continuous measurement for disease prevention and diagnosis have been the focus of much research. Wearable sensors are often used inside the user's body or on biological surfaces. To reduce the burden on the user, these devices must be safe and compact. Lithium has been used as the conventional power source, but lithium batteries are not biocompatible and are not safe. Therefore, biofuel cells (BFCs) that use enzymes as electrodes are expected as a power source. In conventional BFCs, mediated electron transfer (MET) -type enzymes, in which a low molecular weight redox substance (mediator) mediates the electron transfer between the electrode and the enzyme, have been the mainstream. However, the low long-term stability and toxicity of the mediator used has been a challenge. Direct electron transfer (DET) -type enzymes, which do not require a mediator for electron transfer between the electrode and enzyme, are therefore attracting attention. However, there are few reports on DET-type enzymes, and research is being conducted to convert existing MET-type enzymes to DET-type enzymes. Most of the currently reported artificial DET-type enzymes have heme proteins as electron transfer subunits. However, heme proteins have low long-term stability. In the present study, we focused on the electron transfer domain of multicopper oxidase (McoP) from hyperthermophilic archaeon, Pyrobaculum aerophilum, which has excellent long-term stability. McoP has four copper atoms, which can be divided into three types according to their spectroscopic and magnetic properties. Type 1 (T1) Cu makes the enzyme blue and shows strong optical absorption at a wavelength of 610 nm due to d-d transition. Type 2 (T2) Cu is colorless and can be detected by electro paramagnetic resonance spectroscopy (EPR). The T3 type is distinguished by an optical absorption band at a wavelength of 330 nm. T1Cu has a copper atom bonded to two histidine residues and one cysteine, forming a distorted triangular pyramidal structure. T1Cu in McoP also has one methionine axially present, which affects the redox potential of the enzyme and stabilizes it. T1Cu and all ligands are present in domain 3. Therefore, we hypothesized that domain 3 alone could function as an electron-transfer subunit with excellent long-term stability.ExperimentPlasmid vector for expression of domain 3 of McoP was prepared from McoP expression vector using In-Fusion clonig. Subsequently, the protein was expressed in E. coli BL21-Codon Plus (DE3) RIPL. The purified protein was then evaluated and confirmed. Spectroscopic observation showed a peak around 600 nm derived from T1Cu as well as McoP. Cyclic voltammetry (CV) was performed for electrochemical evaluation of domain 3. The prified protein (1 mg/ml) was modified onto a gold electrode by physisorption. Domain 3 modified electrode was used as working electrode. CVs were performed in a three-electrode system using a platinum counter electrode and an Ag/AgCl reference electrode. The CV perfprmed under O2 or N2 saturated condition. The domain 3 modified electrode showed redox peaks. These results indicate that domain 3 can be expressed and functions as an electron transfer subunit. In the future, the present protein will be used as an electron transfar subunit to convert MET-type enzymes to DET-type enzymes. Figure 1

Effect of Cobalt Content on the Properties of Nickel-Cobalt Alloy Coatings

A batch of nickel-cobalt alloy coatings was pulse-electroplated on gun steel (PCrNi3MoVA) surface, in which weight fractions of Co element are 39.9 %, 55.5 %, 67.5 %, and 79.8 %, respectively. The formations of phase and crystal structure in nickel-cobalt coatings were investigated by X-ray diffraction analysis. The layers’ surface morphology and chemical composition were analyzed by scanning electron microscopy coupled with energy dispersive spectrometry. The tribological and nano-mechanical performances of the coatings were used to evaluate by high-speed reciprocating friction and wear tester and nanoindentation tester, respectively. The results showed that the preferred orientation of the coatings gradually changed from (111) to (220) with the rising cobalt content, resulting in changes in the surface morphology of the coatings from pyramidal grains to spherical particles and then to a triangular pyramid structure. As the Co content was 55.5 wt.% in the nickel-cobalt coating, its crystalline grain size reached the smallest value of 11.53 nm, enhancing the hardness and wear resistance.

Evaluation of Candy Retroreflector Using 50μm Triangular Pyramidal Array Structure Mold Fabricated by 3D Lithography

Evaluation of Candy Retroreflector Using 50μm Triangular Pyramidal Array Structure Mold Fabricated by 3D Lithography

Structural and Electronic Properties of LaSin-/0 (n = 2-6) Clusters: Anion Photoelectron Spectroscopy and Density Functional Calculations.

The structures and electronic properties of LaSin- (n = 2-6) anions and their neutral counterparts were investigated by anion photoelectron spectroscopy and theoretical calculations. The vertical detachment energies of the most stable structures of LaSin- (n = 2-6) were measured to be 1.28, 1.58, 2.30, 2.05, and 2.91 eV, respectively. The lowest-energy isomer of LaSi2- is an isosceles triangle with a C2v symmetry. For LaSi3-6- clusters, the most stable isomers are polyhedrons with La atom face-capping the Sin frameworks. The lowest-energy structures of neutral LaSi2,4,5 clusters are similar to their anionic counterparts. The most stable isomer of neutral LaSi3 is a planar structure with C2v symmetry, which is different from the triangular pyramid structure of LaSi3- anion. The lowest-energy isomer of LaSi6- is a C5v symmetric pentagonal bipyramid structure, while for neutral LaSi6 cluster, the C5v structure is not the most stable one. The natural population analysis showed that there is electron transfer from La atoms to Si atoms in LaSin-/0 (n = 2-6). The ZZ tensor component in isochemical shielding surfaces and the anisotropy of the induced current density analyses indicate that the most stable isomer of LaSi6- has aromaticity.

2D layer stacked metallic Cu-serine triangular pyramids and their surface plasmon resonance properties

Abstract 2D copper crystals are synthesized by following a novel solution process. Layer stacked 2D metallic Cu nanostructures are successfully synthesized by chemical reduction using l -Serine and ascorbic acid. SEM and TEM images showed the formation of 2D crystals of copper which are layer by layer stacked to deliver triangular pyramidal structures with embedded spherical as well as rod shaped Cu NPs. Surface Plasmon Resonance (SPR) is studied as a function of pH and concentration of l -serine. SPR is originated from the sharp corners and edges of the triangular pyramid structure and large number of surface particles of copper which are embedded on the 2D copper sheets. The results are highly useful for the development of non-noble metal based SPR sensors.

Triangular pyramidal nano-Ag: Fabrication and properties of superamphiphobic surface on 1060 aluminum alloy mesh

The surface of the superamphiphobic 1060 aluminum alloy mesh with triangular pyramidal nano-Ag structure was prepared by simple chemical deposition. Without the treatment of low surface energy organic compounds containing F or Si element, the surface presents superamphiphobic property after annealing treatment. The surface oxide layer of the aluminum alloy mesh was eroded by acidified AgNO3 solution, and the micro-nano Ag was deposited at the same time. The establishment of micro-nano dual-layer structure results in superamphiphobic property. When water was used as the liquid for contact angle test, the contact angle can reach 163 ± 1°, and the contact angle of glycerol droplet can reach 158 ± 1°. In the meantime, the superamphiphobic 1060 aluminum alloy mesh was found to exhibit excellent corrosion resistance, when using 3.5 wt% NaCl solution as corrosion liquid to corrode superamphiphobic samples. After four days of immersion, the contact angle of water-based is 155 ± 1°, and that of glycerol-based is 152 ± 1°, respectively. Self-cleaning test was also carried out in this paper. It is believed that the superamphiphobic 1060 aluminum alloy mesh prepared by this method has anti-corrosion and self-cleaning properties. It can replace the traditional aluminum in the corrosion environment and keep the surface cleaning.

Bionic stab-resistant body armor based on triangular pyramid structure

A stab-resistant substrate was designed and realized with a triangular pyramidal structure, inspired by the biological armor model in nature. The stab-resistance behavior and dynamic response mechanisms were studied through numerical simulation and experimental testing of a knife impacting a substrate, and an optimal structural design was obtained accordingly, with a tilted angle of 22.5° and optimal thickness of 1.2 mm. It was shown that the triangular pyramidal structure generated twice the internal energy of the knife than the flat substrate due to the dispersing effect of the structure. The force parallel to the inclination caused a significant scratch on the substrate surface, while the force perpendicular caused obvious substrate deformation. A new riveting method was used to form the total layer, which passed the GA 68–2008 standard. The stab-resistant clothing coupled with the reduced wearing burden could provide effective protection and avoid fatal injuries on security personnel working in dangerous environments. The method provided may enlighten the future design and manufacturing of stab-resistant clothing.

Polar Molecule-Based Material with Optic-Electric Switching Constructed by Polar Anions.

Polar crystal structures have attracted more and more attention, due to their unique characteristics, such as ferroelectricity, piezoelectricity, and nonlinear optical property, etc. However, the construction of polar materials is always accidental, and finding an effective synthesis strategy to construct polar materials remains a challenge. Herein, inorganic-organic hybrid compounds of [C7H14N][FeCl4] (1) ([C7H14N] = quinuclidinium cation) and [C7H14N][GeCl3] (2) were prepared, respectively, to verify the beneficial effect of polar anions on the construction of polar crystals. Compound 1 crystallized in the Pbca space group, while 2 belongs to the P43 space group at room temperature. Investigation into the structure of 2 reveals that the polarity of 2 derives from the triangular pyramid structure of [GeX3]- with lone pair electrons. Meanwhile, 2 undergoes a phase transition from the P43 space group to the center Pm3m at 385 K, leading to the optic-electric switching property. Thus, the present work exhibits the advantage of [GeX3]- as the inorganic constituent component in the hybrid polar materials and provides an effective approach for the construction of a polar molecule-based crystal with a switchable property.

Bionic stab-resistant body armor based on triangular pyramid structure

A stab-resistant substrate was designed and realized with a triangular pyramidal structure inspired by the biological armor model in the nature. Through numerical simulation and experimental testing of a knife impacting a substrate, the stab-resistant behavior and dynamic response mechanisms were studied. It was found the stab-resistant performance on the triangular pyramidal substrate was better than the flat plate. The surface of the triangular pyramidal substrate effectively avoided the normal force generated from impacting due to a significant dispersion effect on the tilted pyramid structure. The substrate tended to be inclined and the stress of the backing material was inhomogeneous, absorbing more energy. Much of the deformation energy and others, such as heat and light energy, were caused due to intensive collision between the knife and the substrate, all of which leading to a rapid drop of the knife kinetic energy. The substrate with higher tilted angle led to improved energy dispersion, as well as larger area density. The optimal design parameters were achieved with the knife impacting tests, of which the tilted angle was 22.5° and thickness 1.2 mm. The stab-resistant layer made of the titanium alloy through compression molding consisted of the optimal design parameters. A new riveting method was used to perform the total layer, which passed the GA 68-2008 National Standard. The overall areal density of the stab-resistant layer was 5.85 kg/m2, which was 45% lower than a commonly used stab-resistant layer. The method provided may enlighten the future design and manufacturing of stab-resistant clothing.The full version of this abstract will appear in Defence Technology in 2020.

Precision Cutting of the Molds of an Optical Functional Texture Film with a Triangular Pyramid Texture.

Based on an analysis of the precision and preparation technology of an optical texture film with a triangular pyramid texture, the technical requirements of the original mold were determined, and precision shaping planning technology was adopted to process the original mold. The shape error of the optical texture mold of the triangular pyramid was assessed by defining the area ratio of the retro-reflection. The influence of the tool nose radius and exit burr on the area ratio of the retro-reflection were analyzed. By optimizing the cutting tools, cutting materials and cutting boundaries, a five-axis ultra-precision machining system was used to plan the triangular pyramid structure with a base length of 115 µm and an included angle between two sides of 70.5°. The experimental results indicate that the dimension error of the triangular pyramid element is less than 1 µm, the angle error of the included angle between two sides is less than 0.05°, and the average roughness of the side of the triangular pyramid can reach 9.2 nm, which satisfies the processing quality requirements of the triangular pyramid texture mold.

Power Pylon Reconstruction Based on Abstract Template Structures Using Airborne LiDAR Data

As an important power facility for transmission corridors, automatic three-dimensional (3D) reconstruction of the pylon plays an important role in the development of smart grid. In this study, a novel three-dimensional reconstruction method using airborne LiDAR (Light Detection And Ranging) point cloud is developed and tested. First, a principal component analysis (PCA) algorithm is performed for pylon redirection based on the structural feature of the upper part of a pylon. Then, based on the structural similarity of a pylon, a pylon is divided into three parts that are inverted triangular pyramid lower structures, quadrangular frustum pyramid middle structures, and complex upper or lateral structures. The reconstruction of the inverted triangular pyramid structures and quadrangular frustum pyramid structures is based on prior knowledge and a data-driven strategy, where the 2D alpha shape algorithm is used to obtain contour points and 2D linear fitting is carried out based on the random sample consensus (RANSAC) method. Complex structures’ reconstruction is based on the priori abstract template structure and a data-driven strategy, where the abstract template structure is used to determine the topological relationship among corner points and the image processing method is used to extract corner points of the abstract template structure. The main advantages in the proposed method include: (1) Improving the accuracy of the pylon decomposition method through introducing a new feature to identify segmentation positions; (2) performing the internal structure of quadrangular frustum pyramids reconstruction; (3) establishing the abstract template structure and using image processing methods to improve computational efficiency of pylon reconstruction. Eight types of pylons are tested in this study, and the average error of pylon reconstruction is 0.32 m and the average of computational time is 0.8 s. These results provide evidence that the pylon reconstruction method developed in this study has high accuracy, efficiency, and applicability.

Negative Poisson\u2019s ratio in 1T-type crystalline two-dimensional transition metal dichalcogenides

Materials with a negative Poisson’s ratio, also known as auxetic materials, exhibit unusual and counterintuitive mechanical behaviour—becoming fatter in cross-section when stretched. Such behaviour is mostly attributed to some special re-entrant or hinged geometric structures regardless of the chemical composition and electronic structure of a material. Here, using first-principles calculations, we report a class of auxetic single-layer two-dimensional materials, namely, the 1T-type monolayer crystals of groups 6–7 transition-metal dichalcogenides, MX2 (M=Mo, W, Tc, Re; X=S, Se, Te). These materials have a crystal structure distinct from all other known auxetic materials. They exhibit an intrinsic in-plane negative Poisson’s ratio, which is dominated by electronic effects. We attribute the occurrence of such auxetic behaviour to the strong coupling between the chalcogen p orbitals and the intermetal t2g-bonding orbitals within the basic triangular pyramid structure unit. The unusual auxetic behaviour in combination with other remarkable properties of monolayer two-dimensional materials could lead to novel multi-functionalities.

Surface structures of rutile TiO2(114)

The surface structures of rutile TiO2(114) have been studied using a combination of scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. Depending on the sample preparation, the surface exhibits many complicated local nanostructures, e.g., dot-like, missing row, row-like (1 × 3), and twin dotted (2 × 2) structures. After several cycles of sputtering and high-temperature annealing, all samples exhibit triangular pyramidal structure. Microfaceted structural models, which are composed of combinations of {111} and (001) microfacets, can explain all experimental results as well as the structural variety. The calculated STM images are in good agreement with the experimental results. The decreasing density of dangling bonds, the increasing coordination number, and the evolution of non-polar structures stabilize the surface energy, which results in the microfaceted reconstructions. The formation of various nanostructures and the surface stoichiometric changes are discussed.

Design and fabrication of differently shaped pyramids on Si{100} by anisotropic wet etching

We aimed to produce differently shaped pyramids, that is, eight-sided, triangular, and rhombic pyramids, on the same Si{100} wafer by simply changing mask patterns. A triangular pyramid has an advantage in that it can always become sharp because its vertex becomes a point and is not affected by fabrication errors. A rhombic pyramid that looks like an arrow head was designed to decrease the insertion friction and scar area even if it is inserted deeply into the skin. Triangular and H-shaped etching mask patterns were designed to produce triangular and rhombic pyramid structures on Si{100} on the basis of eight-sided pyramid formation. Both triangular and rhombic pyramids were successfully fabricated as new MEMS structures by applying TMAH anisotropic wet etching (25.0 wt%, 70 °C). A sharp tip with a radius of less than a few hundred nm was obtained in both the triangular and rhombic Si pyramids.

Machining Characteristics of Micro Structure using Single-Crystal Diamond Tool on Cu-plated Mold

The optical film for light luminance improvement of back light unit that is used in light emitting diode/liquid crystal display and retro-reflective film is used as luminous sign consist of square and triangular pyramid structure pattern based on V-shape micro prism pattern. In this study, we analyzed machining characteristics of Cu-plated flat mold by shaping with diamond tool. First, cutting conditions were optimized as V-groove machining for the experiment of micro prism structure mold machining with prism pattern shape, cutting force and roughness. Second, the micro prism structure such as square and triangular pyramid pattern were machined by cross machining method with optimizing cutting conditions. Variation of Burr and chip shape were discussed by material properties and machining method.

Reactive Ion Etching Texturing for Multicrystalline Silicon Solar Cells Using a SF6/O2/Cl2 Gas Mixture

Maskless random reactive ion etching (RIE) texturing employing a SF6/O2/Cl2 gas mixture was investigated in order to achieve higher efficiencies in multicrystalline silicon (mc-Si) solar cells. Triangular pyramid structures with an aspect ratio of 1 were formed and, when the RIE power increased, the average reflectance was reduced by about 1.46% per 10 W. This was due to the increased density of the surface features. The performances of all of the RIE-textured mc-Si solar cells were improved compared with that of the reference cell. Among them, the 110 W cell, which had a 0.6% higher efficiency than the reference cell, had the highest efficiency of 16.82%. An impedance analysis was carried out to determine series resistance (Rs), shunt resistance (Rsh), and junction capacitance (Cj). Interestingly, the cell with higher efficiencies and higher structure densities had higher linear reverse currents.

Investigation of surface features using reactive ion etching method for the enhanced performance of multi-crystalline silicon solar cells

Maskless, random RIE texturing with a gas mixture of SF6/O2 (SO) and SF6/O2/Cl2 (SOC) was investigated to achieve higher efficiency for mc-Si solar cells. Cone structure with aspect ratio of 3.7 was highly effective for reducing surface reflectance particularly for wavelength from 310 to 700nm and triangular pyramid structure with aspect ratio of 2 revealed rather uniform reduction of reflectance with respect to the optimized wet texturing for whole wavelength range of 310–1100nm. On the contrary to results of reflectance, performances of fabricated cell were much better for triangular pyramid structure than cone structure. The degradation of cell performances for the cone structure was assigned both to the poor e-h pair generation efficiency relevant to the formation of highly defective surface layer with high density recombination centers, and ohmic shunt. The efficiency enhancement by 0.6% in mc-Si solar cells with triangular pyramid structures was assigned also to the slightly enhanced e-h pair generation efficiency with respect to the reference cell.

The effect of texture unit shape on silicon surface on the absorption properties

Improving the utilization ratio of sunlight is a key factor for the development of solar cell. In this work, different structures including triangular pyramid, rectangular pyramid, hexangular pyramid and cone structure are established to investigate the influences of many factors, like geometrical shape, density and the top angle of the texture unit on silicon front surface to sunlight absorption. Ray-tracing technology is used for simulation. The simulation results indicate that the triangular pyramid texture on silicon front surface performs the best, and its total absorption rate is more than 90% for the light with wavelength between 640 and 1080 nm when the top angle of pyramid is less than 100°.

Electronic states of Ga 3Si, GaSi 3, and their ions

The equilibrium geometries and electronic states of Ga 3Si, GaSi 3, and their ions are investigated using the complete active space self-consistent-field (CASSCF) and DFT(B3LYP)/CCSD(T) techniques. The 2B 1, 3B 1, and 1A 1 states in C 2v symmetry with a planar quadrilateral geometry are found to be the ground states of Ga 3Si, Ga 3Si +, and Ga 3Si −, respectively. On the other hand, the ground states of GaSi 3, GaSi 3 − are also predicted to undergo Jahn–Teller distortion to the 2A″ and 1A′ states in C s with a distorted triangular pyramid geometry, respectively, whereas that of GaSi 3 + is found to be the 1A 1 state in C 3v with symmetric triangular pyramid structure. Binding energies, electron affinities, ionization energies of Ga 3Si and GaSi 3 are computed at the CCSD(T)/QCISD(T) level and discussed.

Spectroscopic properties of mixed gallium arsenide tetramers: GaAs3±, GaAs3, Ga3As±, and Ga3As

Spectroscopic properties of the low-lying electronic states of Ga3As, As3Ga, and their anions and cations are computed by the complete active-space self-consistent field (CASSCF) followed by multireference singles+doubles configuration interaction (MRSDCI) calculations that included up to 4.4 million configurations. Whereas the ground state of Ga3As is found to be a symmetric triangular pyramidal (C3v) A11 structure, the ground state of As3Ga is predicted to undergo Jahn-Teller distortion to a Cs A′1 state with a folded geometry. The ground state of the Ga3As− ion is found to be surprisingly a planar (C2v) structure but the ground state of the GaAs3− ion exhibits a Cs nonplanar Jahn-Teller distorted geometry. The energy separations of a number of excited electronic states have been computed to predict the spectra of these species. The equilibrium geometries, vibrational frequencies, atomization energies, adiabatic ionization potentials, electron affinities, and other properties for the electronic states of Ga3As and As3Ga are computed and discussed. Large differences in the equilibrium geometries of the Ga3As− anion and the neutral Ga3As are predicted to result in considerable vibrational progression the anion photoelectron spectra.