Planar Components Research Articles

An unanticipated discourse of HB-EGF with VANGL2 signaling during embryo implantation

Implantation is the first direct encounter between the embryo and uterus during pregnancy, and Hbegf is the earliest known molecular signaling for embryo-uterine crosstalk during implantation. The downstream effectors of heparin-binding EGF (HB-EGF) in implantation remain elusive due to the complexity of EGF receptor family. This study shows that the formation of implantation chamber (crypt) triggered by HB-EGF is disrupted by uterine deletion of Vangl2, a key planar cell polarity component (PCP). We found that HB-EGF binds to ERBB2 and ERBB3 to recruit VANGL2 for tyrosine phosphorylation. Using in vivo models, we show that uterine VAGL2 tyrosine phosphorylation is suppressed in Erbb2/Erbb3 double conditional knockout mice. In this context, severe implantation defects in these mice lend support to the critical role of HB-EGF-ERBB2/3-VANGL2 in establishing a two-way dialogue between the blastocyst and uterus. In addition, the result addresses an outstanding question how VANGL2 is activated during implantation. Taken together, these observations reveal that HB-EGF regulates the implantation process by influencing uterine epithelial cell polarity comprising VANGL2.

Analysis of Acousto-Optic Phenomenon in SAW Acoustofluidic Chip and Its Application in Light Refocusing.

This paper describes and analyzes a common acousto-optic phenomenon in surface acoustic wave (SAW) microfluidic chips and accomplishes some imaging experiments based on these analyses. This phenomenon in acoustofluidic chips includes the appearance of bright and dark stripes and image distortion. This article analyzes the three-dimensional acoustic pressure field and refractive index field distribution induced by focused acoustic fields and completes an analysis of the light path in an uneven refractive index medium. Based on the analysis of microfluidic devices, a SAW device based on a solid medium is further proposed. This MEMS SAW device can refocus the light beam and adjust the sharpness of the micrograph. The focal length can be controlled by changing the voltage. Moreover, the chip is also proven to be capable of forming a refractive index field in scattering media, such as tissue phantom and pig subcutaneous fat layer. This chip has the potential to be used as a planar microscale optical component that is easy to integrate and further optimize and provides a new concept about tunable imaging devices that can be attached directly to the skin or tissue.

Silicon Fresnel Zone Plate Metalens with Subwavelength Gratings.

Metalenses are planar optical components that have demonstrated immense potential for integrated optics. In particular, they are capable of high-efficiency subwavelength focusing without the bulkiness of traditional lenses. Dielectric metalenses operating in the C-band typically employ relatively tall, amorphous silicon structures arranged in a periodic array. Phase control spanning from 0 to 2π is accessed by varying the geometry of these scattering structures. The full 2π phase range is necessary to impose a hyperbolic focusing phase profile, but this is difficult to achieve without custom fabrication practices. In this work, we propose a binary phase Fresnel zone plate metalens designed for the standard 500 nm silicon-on-insulator platform. Our design uses subwavelength gratings with trapezoidal segmentation to form concentric rings. The effective index of the grating is set with the duty cycle using a single full-etch step to form the binary phase profile of the zone plate. The metalens design can be easily tuned to achieve longer focal lengths at different wavelengths. It offers a simple platform for high-throughput wavelength-scale focusing elements in free-space optics, including for microscopy and medical imaging.

60 nm Span Wavelength-Tunable Vortex Fiber Laser with Intracavity Plasmon Metasurfaces

Wavelength-tunable vortex fiber lasers that could generate beams carrying orbital angular momentum (OAM) hold great attention in large-capacity optical communications. The wavelength tunability of conventional vortex fiber lasers is, however, limited by a range of ∼35 nm due to narrow bandwidth and/or insertion loss of mode conversion components. Optical metasurfaces apart from being compact planar components can flexibly manipulate light with high efficiency in a broad wavelength range. Here, we propose and demonstrate for the first time, to the best of our knowledge, a metasurface-assisted vortex fiber laser that can directly generate OAM beams with customizable topological charges. Due to the designed broadband gap-surface plasmon metasurface, combined with an intracavity tunable filter, the laser enables an OAM beam with a center wavelength continuously tunable from 1015 to 1075 nm, nearly twice of other vortex fiber lasers ever reported. The metasurface can be designed at will to satisfy requirements for either low pump threshold or high slope efficiency of the laser. Furthermore, the cavity-metasurface configuration can be extended to generate higher-order OAM beams or more complex structured beams in different wavelength regions, which greatly broadens the possibilities for developing low-cost and high-quality structured-beam laser sources.

Compressibility effects on turbulence production

Turbulence in compressible flows plays a major role in a variety of applications such as air/fuel mixing strategies for scramjet combustors. Therefore, the ability of controlling its production is of particular interest. However, compressible turbulence is more challenging than its incompressible counterpart due to the fact that thermodynamic quantities also fluctuate. In particular, the compressible turbulent kinetic energy production is a function of both velocities and density fluctuations. The so-called Morkovin's hypothesis has been often used in the literature to express the density fluctuations as a function of the velocity ones and the local Mach number. In this work, we discuss the validity of this hypothesis, and we use its expression to reformulate the turbulence production as a function of velocity only. The resulting expression shows that the planar component of turbulence production is substantially unaffected by compressibility effects. This result validates a previous work aimed at the sustainment of turbulence production using streamwise vortices. On the other hand, the turbulence production terms aligned with the convective velocity are affected by compressibility, even at relatively low Mach numbers.

Absolute wavelength scanning interferometry for measuring the thickness of optical elements.

A technique for measurement of the thickness of optical elements using absolute wavelength scanning interferometry is presented in this paper. To achieve high-grade optical components and systems, the thickness of both planar and non-planar optical components must be measured with an accuracy of a few micrometers. The proposed technique is based on the Fizeau interferometer and interconnects data from three different tunable laser diodes yielding a long effective wavelength range and thus low measurement uncertainty. The uncertainty of the central thickness measurement ranges from hundreds of nanometers to a few microns. The method allows to measure the thickness of both flat optical elements as well as lenses with curved surfaces. Moreover, the areal information provided by the interferometry and its high angle sensitivity help to quickly and precisely align the measured component and reduce misalignment errors. The results of thickness measurements have been validated and cross-tested with other techniques. In addition to the thickness, the technique provides some additional information (wedge, surface form error) in the case of flat samples and can be easily and quickly modified (mounting of a Fizeau transmission sphere) to measure other essential parameters of optical elements. Thus, this one approach can replace many single-purpose measuring devices while maintaining high accuracy.

Thermal Modeling of Planar Magnetics: Fundamentals, Review and Key Points

High-frequency and high-power density converters are essential for many applications such as automotive and more electric aircraft. To improve power density, planar magnetic components are increasingly used in power electronic converters owing to their advantages, such as less high-frequency losses, repeatability, and better thermal performance compared to conventional wound components. Considerable attention has been paid to their electrical performance. However, the thermal aspects are essential for enhancing completely their performance. Currently, there is an increasing interest in these critical aspects of high-density power converters. This paper presents a literature review of studies on the thermal modeling of planar magnetics. The papers were organized according to the model type and analyzed to highlight their merits and limitations. A multicriteria comparison of the studied papers was performed. Moreover, the key points and issues related to the thermal modeling are addressed to guide designers in enhancing the thermal aspects of planar magnetic components.

Количественный анализ текстуры деформации и первичной рекристаллизации при угловой прокатке и отжиге магнитострикционного сплава (Fe83Ga17)99B1

The Fe–Ga alloy is a promising magnetostrictive material thanks to of the optimal combination of functional properties and relatively low price due to the absence of rare-earth elements in the composition. To obtain the maximum magnetostriction in Fe–Ga polycrystals, it is necessary to create a crystallographic texture with a predominance of the <100> direction, since the tetragonal magnetostriction constant is the largest. Traditional methods of thermomechanical treatment do not lead to the formation of such a texture in a bcc alloy. In this paper, for the first time, the authors propose to use inclined rolling to increase the proportion of favorable texture components. Warm rolling with a deformation degree of 70 % was carried out at angles of 0, 30 and 90° to the direction of hot rolling. The deformation texture was examined using X-ray texture analysis and the texture and structure of the material after recrystallization was analyzed by electron backscatter diffraction (EBSD) on a scanning electron microscope. Quantitative texture analysis was carried out using the orientation distribution function (ODF) method using the ATEX software. The volume fraction of some texture components was calculated. The study shows that a significant change in the deformation textures and primary recrystallization occurs during rolling at an angle of 90°. The sample after such rolling contains the largest amount of the planar component {100}. The study identified a relationship between the texture of deformation and recrystallization in Fe–Ga: to increase the proportion of components with the <001> crystallographic direction during recrystallization, the presence of planar components {111} in the deformation texture is necessary, which is associated with the predominant growth of favorable components in the deformation matrix with such a texture.

A novel method to control stress distribution and machining-induced deformation for thin-walled metallic parts

Abstract In the precision machining of thin-walled planar components, the initial residual stress of the workpiece could lead to subsequent deformation after machining, which influences the geometrical accuracy of the final parts. Generally, conventional methods, such as stress-relief annealing and vibration stress relief, are implemented to reduce the magnitude of the residual stress. However, the distribution of the residual stress, which is more significant to the machining accuracy for thin-walled parts, is difficult to be adjusted in these methods. This article proposes a novel method to control the stress distribution and magnitude during the manufacturing process and thus reduce the machining-induced deformation for the thin-walled planar part of pure copper. In this method, symmetrical distribution of residual stress is introduced by multi-pass rolling, quenching, stress-relief annealing, and turnover turning. The stress field and deformation of the part are predicted by finite element modeling in the whole process. The part deformation after machining is verified by the experiments. The results show that compared with the traditional stress-relief annealing, this novel method could reduce the part deformation after machining and improve the geometrical accuracy for thin-walled parts.

Cooperativity in Shape-Persistent Bis-(Zn-salphen) Catalysts for Efficient Cyclic Carbonate Synthesis under Mild Conditions.

A series of conformationally rigid (Zn-salphen)2 complexes with a planar bridging component (xanthene or dibenzofuran) are described. Conformational changes for these assemblies are essentially limited to the axial rotation of the Zn-salphen moieties; however, such geometric constraints crucially permit the subtle tuning of the intermetallic separation and geometry to potentially enhance catalytic activity (and cooperative effects). The complexes have been investigated as catalysts in conjunction with nBu4NI for the coupling of CO2 with epoxides. Selected dibenzofuran derivatives are significantly more active for the production of cyclic carbonate than their mononuclear analogues under identical conditions and concentrations of Zn sites. High initial turnover frequencies (up to 29 000 h-1; 14 500 h-1 per Zn, using 10 bar of CO2 at 95 °C) and excellent efficiencies under mild conditions (1 bar of CO2 at 55 °C) have been achieved. Kinetic studies using in situ (ReactIR) spectroscopy and density functional theory calculations have been performed, which reveal the existence of an intramolecular rate component and a preference for the cooperative pathway as well as transition states that depict the Zn sites operating in tandem. Taken together, these results provide strong evidence of cooperative reactivity in these Zn2 catalysts.

Comparative Study of Four-Point Measurements of Copper Thin Films Resistivity in Aligned and Square Configuration at Low Frequencies

The main objective of this research work is the comparison of the two Van Der Pauw four-point measurement configurations (aligned and square) commonly used to measure the resistivity of metal thin films which are widely used in the manufacture of planar components such as inductors, transformers, insulators, circulators, etc. Electrical characterization is very important because it ensures the quality of the metal supposed to conduct electrical current in the components mentioned above.
 The resistivity measured by using the square or aligned configuration sometimes has significant differences. Making a comparative study therefore allow to know which gap between points, which frequencies to choose when measurements must be made by using square or aligned configuration.
 In this paper, the measured thin films are made of copper which is broadly used in the structures because of its physical, chemical and mechanical properties [1]. The copper is deposited on alumina substrates by magnetron radiofrequency sputtering. Rectangular alumina substrates of dimensions 50mm x 20mm x 635μm were used. Thin film resistivity measurements using a four-point measurement method were performed by using HP 4284A LCRmeter in the frequency range of a few Hz to a few kHz. The comparison was made between the four-point aligned method and the four-point square method based on the frequency, the gap between points and the thin film thickness was made.
 The results obtained by the study show that both configurations measure the same resistivity up to 1 kHz and then the increase of resistivity in aligned configuration limits its use beyond this frequency. The square configuration can still measure the same resistivity up to 40 kHz. The study also shows that the gap between points is limited to 3 μm in aligned configuration while the square configuration allows a gap up to 5 μm.

Extended Metasurface Spin Functionalities from Rotation of Elements

AbstractMetasurfaces are a class of planar optical components that are engineered to manipulate electromagnetic waves, including their spin states in terms of circular polarizations. For example, the Pancharatnam–Berry (PB) phase has been exploited in metasurfaces for various spin functionalities, but these spin functionalities, exhibit conjugate relations for spin states. Recent advances combining the PB phase and propagation phase have implemented completely independent spin functionalities for spin states. However, the spin functionalities are fixed once the metasurfaces are designed. Here, this work proposes and demonstrates that the spin functionalities designed from the PB phase and propagation phase can be further extended by simply rotating the elements in a metasurface. This extension is based on a relationship between phase profiles of spin states that are acquired before and after the rotation. Proof‐of‐concept demonstrations are performed for the extended spin functionalities, including the conversion from spin angular momentum to orbital angular momentum, and spin‐dependent holograms. This extension may find use in relevant applications such as polarized display and dual‐polarized holography.

Fringing Field Analytical Calculation of High Frequency Planar Magnetic Components

When the switching frequency is above 100 kHz, the winding loss of the round wire magnetic component will increase sharply due to skin effect and proximity effect, which greatly limits its wide application. On the contrary, the planar magnetic component can not only work at such high frequency, but also suitable for high power density applications for its low profile. However, in order to avoid core saturation and change the inductance, the air gap is usually required in the design of the planar magnetic component, which will produce fringing effect and further increase the winding loss. Based on Roshen’s assumptions, this paper analyzes the planar magnetic component with center air gap. Firstly, the Schwartz-Christoffel mapping is used to establish the mapping relationship between the air gap fringing region and the strip region. Then the magnetic field intensity in complex form is obtained by the complex potential function and the one in vector form is given, which is represented by the strip region coordinate. Finally, the magnetic field intensity verification and the thermal verification are carried out. The method proposed in this paper provides effective guidance for the design of planar magnetic components operating at high frequency.

The V-MVLE model for cyclic failure behavior simulation of planar RC members

As a widely used planar structural component, the reinforced concrete (RC) shear wall in service is usually subjected to axial, bending and shear loading, possessing high dissymmetry damage mechanics of concrete and failure mode of steel bars. To obtain a satisfactory level of simulation accuracy for the cyclic failure behavior of RC shear walls, progresses were made both in microscopic and macroscopic modeling method. In this study, a hybrid planar model based on vector form intrinsic finite element (VFIFE) and macroscopic multi-vertical line element (MVLE) was proposed, which combined the merits of detailed response of the microscopic model and high calculation efficiency of the macroscopic model. Owing to particle-based formulation along the path element, no assembling of a global stiffness matrix was required by the VFIFE method, which attributed the advantages in large deformation and reinforcement fracture behavior analysis for the proposed model during cyclic failure phase. Via the proposed hybrid model of MVLE, the RC shear walls with various parameters, involving axial compression ratios and height–weight​ ratios, were simulated to allow comparison between the experimental and analytical results in reversed cyclic tests, which demonstrated good agreement and satisfied calculation efficiency.

Contribution to Lateral Torsional Buckling of Girders with Rotational Restraints

AbstractThe instability case of lateral torsional buckling (LTB) under bending load My is known to be of decisive importance in the design of beams with open cross‐sections. This instability case is expressed by a lateral displacement and simultaneous torsion (or twisting) of the member axis. The restraint of one or both of these deformation components represents an effective and practice oriented method to stabilize beams against LTB. In practice, therefore, use is made of regulations from the current version of EN 1993‐1‐1:2010, Annex BB, which allow for the consideration of the stabilizing effect of continuous and planar components directly connected to the compression chords of the beams. This paper presents the results of a study that investigated the effects of the innovations introduced in the draft standard for the 2nd generation of EN 1993‐1‐1 for the LTB verification of beams with I and H cross‐sections on the regulations for the calculation of the minimum stiffness of a rotational restraint to avoid LTB. In the first part of the paper, the background of the existing and new regulations is discussed together with previous proposals for adapting the definition of the minimum rotation restraint. In addition, a comparison is made with current specifications for the minimum rotational stiffness contained in the National Annex of DIN EN 1993‐1‐1. Subsequently, the regulations of the minimum rotational stiffness in prEN1993‐1‐1, Annex D are assessed.

Ferroelectric polarization of β-polyvinylidene fluoride as control and mitigator of infectious organisms

In this work, Polyvinylidene fluoride (PVDF), a ferroelectric polymer thin film, was prepared by the solution casting method. The growth of polymer films was optimized to achieve the ferroelectric β–phase with PVDF and, most importantly, ferroelectric domains with dominant planar polarization components. The ferroelectric polarization of these polymers is known to hold surface charges with/without field. The polymer is expected to interact with microbial organisms whose physiological metabolism depends on surface charges. The current COVID-19 pandemic has motivated us to carry out a fundamental study of the interaction between the polarization of the ferroelectric polymers and microbes. The antimicrobial studies were performed, making these polymer films interact with bacterial, viral, and fungal growth environments. Electroded PVDF films were kept in contact with bacterial colonies, and a dc-voltage of 1.5 V was applied across the electrodes. The film was subjected to 1.5 V and kept in contact with the culture before the growth initiation, and the microbial growth was hindered entirely. It never occurred either beneath or over the surface of the films. Thus, in the presence of the electric field, the microbial growth was inhibited, even in a conducive environment.

A compact tri‐band filter based on a dual‐capacitively loaded triple‐mode substrate integrated waveguide resonator

This letter presents a compact tri-band filter using a dual-capacitively loaded (DCL) substrate integrated waveguide (SIW) triple-mode resonator. The frequencies of TE101, TE102, and TE103 are shifted lower by the capacitive loading effect, which is achieved by the DCL structure. A compact tri-band example filter is then built by using two DCL triple mode SIW resonators. Following that, seven transmission zeros are generated to improve filter selectivity by vertical coupling of two cavities. The area of the filter occupies only 0.46 λg2. The measured results demonstrate that this compact tri-band filter has the advantages of flexible control of passbands, easy interconnection with other planar radio frequency components, making it promising for millimeter wave implementations and 3D-integrated systems.

Analysis of the smoothing characteristics and shape-retaining ability of conformal vibration polishing and suppression strategy for full-spatial frequency errors of optics.

Conformal vibration polishing (CVP) employing flexible polishing tools is expected to be an efficient means of optical processing, and all current research on it is limited to planar components. Hence, the smoothing characteristics of the middle spatial frequency (MSF) errors and the ability to maintain the surface shape of different types of optics in CVP are analyzed. A combined processing method based on magnetorheological finishing and CVP for full-spatial frequency errors is proposed and verified by experiment. The peak-to-valley value, MSF errors, and surface roughness of the large-diameter component can reach 75 nm, 1.1 nm, and 0.37 nm after 9 h of processing. The research not only demonstrates the excellent removal characteristics of CVP and the effectiveness of the proposed method but also provides an additional choice for the high-precision manufacturing of optics.

Improving the dyeing and fastness performance of molecular triphenodioxazine on wool and nylon fabrics

Three novel triphenodioxazine acid dyes (phosphorous-containing acid dyes; PAD2–4) modified by phenophosphazine with non-planar conformation were designed and synthesized. Their dyeing and fastness performance on wool and nylon fabrics were discussed in comparison with the performances of traditional triphenodioxazine (TPDO) dyes such as C.I. Direct Blue 106 and C.I. Reactive Blue 198. The excellent dyeing and fastness performance of PAD2–4 on the wool and nylon fabrics were analyzed using DFT calculations. The phosphinic group of these PADs is thought to play a key role in the improvement of the exhaustion dyeing performance; the easier offset face-to-face stacking arrangement was attributed to the overwhelming increase of the rubbing fastness owing to the stronger Van der Waals interactions, as calculated using DFT. A design strategy that includes the introduction of an extra-weak acid group and a zigzagged rigid planar component into the TPDO matrix offers insight into improving the poor exhaustion and fastness performance of traditional TPDOs.

Fabrication of Sectionally Permeable Components with Curved Surface by Laser‐Beam Powder‐Bed Fusion

AbstractDevices in process engineering often include permeable components. As shown in our recent work for planar components, laser‐beam powder bed fusion offers the opportunity to integrate permeable sections into complex monolithic metal parts in one go. This paper extends the approach to components with curved surfaces. Different scan strategies were investigated for their effects on surface morphology and permeability of tubular samples. It was found that in order to ensure consistent properties of a permeable tube, different starting points or rotation of the scan vectors have to be used.