Enhancement of gain using a multilayer superstrate metasurface cell array with a microstrip patch antenna

This research presents a new idea in the use of wireless communication antennas: it uses a multi-layered array of cells called a superstrate multi-layer metasurface (MTM) and is placed in front of a patch of microstrip antenna to absorb surface waves and prevent them from passing through the insulating material, which reduces the permeability of the insulator and thus improves the Antenna properties, The proposed hexagonal cell with resonators is placed on the flame resistant (FR4) substrate, with a relative permittivity of 4.3 and an area (14×14) mm2 . It was tested when the metasurface layer is 4 mm in front of the patch and the distance between the metasurface layers is 2 mm. The optimum distances were calculated by the sweep parameter, and the improved antenna gain and the input reflection coefficient were obtained together. (S11) has been improved from -31.217 to -38.338 dB and, the gain from 3.28 dB to 6.554 dB.

The Negative Poisson’s Ratio Ship Base Design and Vibration Isolation Performance Analysis

This paper mainly studies the vibration isolation of negative Poisson’s ratio structure in the honeycomb base of ships. Based on the structure of the negative Poisson’s ratio structure, different laying methods and different cell structure are used to construct the honeycomb base with the re-entrant hexagonal cell, the mathematical expression of Poisson’s ratio of a single re-entrant hexagonal cell structure is obtained through theoretical analysis. The negative Poisson ratio and relative density could be got by changing the angle and side thickness of the cell structure. Based on the different energy band of the re-entrant hexagonal cell structure, the different negative Poisson’s ratio re-entrant hexagonal honeycomb base was got, the energy band and the frequency response curve of the ship base are analyzed by COMSOL software. The energy band diagram and the frequency response of the structure are obtained to analyze the vibration isolation performance of the honeycomb base. By comparing the experimental results, the following conclusions can be gotten: (1) Compared with the traditional base, the negative Poisson’s ratio base has better vibration isolation effect on external excitation; (2) Different laying method and Poisson ratios can get different isolation effect. The combined base structure can provide better isolation effect to the external excitation in a larger frequency band; (3) By adding different mass blocks to the inner or peripheral angles of the basic re-entrant hexagonal cell, the vibration isolation performance of the structure can be changed to better.

Early Postoperative Effects of Uncomplicated Phacoemulsification Surgery on Corneal Endothelial Cells and Thickness in Patients with Pseudoexfoliation Syndrome

Purpose: To compare early postoperative effects of uncomplicated phacoemulsification surgery on corneal endothelial cells and thickness in patients with pseudoexfoliation syndrome (PEX).Methods: One eye each of 32 patients with PEX and 32 age-matched non-PEX subjects was evaluated preoperatively and on 1st, 7th, and 30th days after uncomplicated phacoemulsification surgery in this retrospective case-control study. Nuclear firmness, corneal edema (CE), anterior chamber reaction (ACR) intensity were graded by a slit-lamp microscope. Endothelial cell density (ECD), coefficient of variation in cell area (CV), hexagonal cell ratio (HEX), and central corneal thickness (CCT) were measured using a noncontact specular microscope.Results: There was no significant group-difference in age, sex, corneal edema (CE), anterior chamber reaction (ACR), coefficient of variation in cell area (CV), and hexagonal cell ratio (HEX). Mean effective phaco time (EPT) was significantly lower intraoperatively (p<0.001) and logarithm of the minimum angle of resolution (logMAR) values of best-corrected visual acuity (BCVA) were significantly higher on both 1st (p<0.001), 7th (p=0.011), and 30th (p=0.025) days postoperatively in the PEX group than in the non-PEX group. Mean ECD was significantly lower in the PEX group than in the non-PEX group on 7th (p=0.013), and 30th (p=0.037) days postoperatively. The mean CCT significantly differed only on 1st (p<0.001) day postoperatively.Conclusion: Eyes with PEX presented lower corneal ECD and decreased BCVA after uncomplicated phacoemulsification surgery. Further, there was no association between CCT and PEX existence preoperatively and in the early postoperative period.

A Novel Hexagonal Beam Steering Electrowetting Device for Solar Energy Concentration

Traditional tracking devices for solar energy applications have several disadvantages, such as bulky mechanical structure, large wind loads, and ease of misalignment. This study aims to design a flat, thin, and adaptive beam steering device to eliminate these drawbacks. A proof of concept device was fabricated to demonstrate this design. The novelty of the proof of concept device is the hexagonal structure of the electrowetting cell design. The hexagonal cell was dosed with two immiscible liquids with different refractive indices. The hypothesis of this design is that by deforming the liquid shape with the application of voltage, light can be steered and concentrated for solar energy applications. A maximum contact angle change of 44° was observed with the application of 26 V to one of the electrodes of the hexagonal cell. The device demonstrated a 4.5° change of laser beam path with only a 0.2 refractive index difference of the liquids. The 3D simulation model developed in this study shows that a tilted and flat interface can be achieved using higher dielectric constant dielectric materials. The device can facilitate the planer steering and concentration of sunlight for rooftop applications without moving mechanical parts.

Two new minerals, badengzhuite, TiP, and zhiqinite, TiSi₂, from the Cr-11 chromitite orebody, Luobusa ophiolite, Tibet, China: is this evidence for super-reduced mantle-derived fluids?

Titanium minerals enclosed in corundum separated from the Cr-11 orebody include native Ti, zamboite (FeTiSi2), osbornite (TiN)-khamrabaevite (TiC) solid solutions, and jingsuiite (TiB2), as well as the new minerals badengzhuite (TiP) and zhiqinite (TiSi2) and two potentially new minerals, Ti11(Si,P)10 and Ti10(Si,P,□)7, where □ indicates a vacancy. These minerals together constitute a spheroid 20 µm across inferred to have crystallized from a droplet of Ti–Si–P intermetallic melt. Energy-dispersive spectroscopy and three-dimensional electron diffraction were applied to characterize the two new minerals. Badengzhuite has a primitive hexagonal cell with a=3.49(7) Å, c=11.70(23) Å, V=124(4) Å3, and crystallizes in space group P63∕mmc (Z=4). It is isostructural with synthetic TiP. Two EDX (energy dispersive X-ray spectroscopy) analyses of badengzhuite gave 60.56 wt %Ti and 39.44 wt % P and 62.74 wt % Ti and 37.26 wt % P from which an empirical formula of Ti1.020P0.980 was calculated on the basis of two atoms (ideally TiP). Zhiqinite has a primitive orthorhombic cell with a=8.18(16) Å, b=4.85(10) Å, c=8.42(17) Å, V=334(12) Å3, and crystallizes in space group Fddd (Z=8). It is isostructural with synthetic TiSi2 (C54 type). Four EDX analyses of zhiqinite gave 39.58–44.79 wt % Ti and 55.21–60.42 wt % Si, from which an empirical formula of Ti0.905Si2.095 was calculated on the basis of three atoms (ideally TiSi2). We suggest that interaction of mantle-derived CH4 + H2 fluids with basaltic magmas in the shallow lithosphere (depths of ∼ 30–100 km) under conditions more reducing than 6 log units below the oxygen fugacities corresponding to the iron–wüstite buffer resulted in precipitation of corundum that entrapped intermetallic melts, some of which crystallized to ultra-reduced Ti–P–Si phases. Experimental work on the Ti–Si and Ti–P systems indicates that the minerals enclosed in corundum could have crystallized from the alloy melt at the lowest temperature accessible on the liquidus. It has been alleged that these ultra-reduced phases are anthropogenic contaminants inadvertently introduced with fused alumina abrasive during preparation of mineral separates. Nonetheless, we conclude that the differences between the ultra-reduced minerals in the separates and the ultra-reduced phases in fused alumina are more convincing evidence for these minerals having a natural origin than the similarities between them are evidence for an anthropogenic origin.

Design and Fabrication of 4H-Sic Mosfets with Optimized JFET and p-Body Design

In this paper, 4H-SiC planar MOSFETs were designed and fabricated. By using TCAD tool, the trade-off between on-resistance and maximum gate oxide electric field was optimized. With optimized gate oxide growth process, the gate oxide’s critical electric field of 9.8 MV/cm and the effective barrier height of 2.57 eV between SiO2 and 4H-SiC were obtained. The field effective mobility with different p-body doping was compared and studied. The MOS interface state density of 1.12E12 cm-2eV-1 at EC - EIT = 0.21 eV and channel mobility of 19.3 cm2/Vs at VGS = 20 V were obtained. The fabricated MOSFET’s on-resistance of 6.4 mΩcm2 was obtained with hexagonal cell structure which is very consistent with the simulation results.

Antipenetration Performance of Honeycomb Shelter under Two Repeat Projectile Strikes

Antipenetration performance of honeycomb shelter under two repeat projectile strikes is investigated via test and numerical simulation. Among them, there are two kinds of test targets: cylindrical honeycomb structure target and reinforced concrete target; a numerical simulation target is a honeycomb-structure target composed of hexagonal honeycomb unit, and the size of the target is the same as that of the honeycomb-structure target in test. The results show that the damage area of the honeycomb-structure target is smaller than that of the reinforced concrete target under projectile strikes with approximately the same velocity. The damage range of the honeycomb-structure target is limited within the hexagonal cell getting contact with projectile left other cells with no damage. During the two repeat projectile strikes, the first projectile will deflect to some extent just as single projectile strike. The deflection of the second projectile is larger and is related to the distance between the strike points of the two projectiles. The results show that honeycomb shelter performs good under two repeat projectile strikes.

Multicomponent Phases with CeAl2Ga2- and Y0.5Co3Ge3-Type Structures in the Gd–Ca–Fe–Co–Ge System

New quinary phases with the CeAl2Ga2 (tI10, I4/mmm) and Y0.5Co3Ge3 (hP8-2, P6/mmm) structure types were found at 500 ºC in the Gd–Ca–Fe–Co–Ge system based on X-ray powder diffraction data. They are Gd1‑xCaxFe2‑yCoyGe2 (x = 0.085(7)-0.551(6), y = 0.25-0.75, a = 3.99468(6)-4.00003(8), c = 10.1279(2)-10.3981(5) Å) and Ca0.5‑xGdxFe3‑yCoyGe3 (x = 0.031(1)-0.314(8), y = 0.75-2.25, a = 5.1081(1)-5.1218(1), c = 3.9751(1)-4.0451(2) Å). The c-parameter of the tetragonal CeAl2Ga2-type (122) phase cell depends much more on the Fe/Co and Gd/Ca ratios, than the a-parameter (which remains nearly the same). The volume of the 122 cell increases with increasing Fe and Ca content. The c-parameter of the hexagonal cell of the Y0.5Co3Ge3-type (0.533) phase also depends more strongly on the Fe/Co content than the a-parameter, but Gd/Ca substitutions have little effect on the cell parameters. The following new quaternary and ternary phases were also discovered: GdFe2‑yCoyGe2 (y = 0.5-1.5, a = 3.99419(5)-3.99750(7), c = 10.3271(2)-10.1173(3) Å) with CeAl2Ga2-type structure and Gd0.5Fe3‑yCoyGe3 (y = 0.75-1.5, a = 5.1247(8)-5.1225(7), c = 4.052(1)-4.010(1) Å), Ca0.5Fe3‑yCoyGe3 (y = 0.75-2.25, a = 5.1153(2)-5.1066(2), c = 4.0451(2)-3.9839(3) Å), Ca0.5Fe3Ge3 (a = 5.10167(9), c = 4.06565(7) Å), and Ca0.5Co3Ge3 (a = 5.0899(2), c = 3.9199(1) Å) with Y0.5Co3Ge3-type structure.