Polarization Separation Research Articles

SYNTHESIS, ANALYSIS AND SEPARATION OF ISOMERIC INDENO- AND INDOLOQUINOXALINES

Due to the increasing number of respiratory diseases with developed inflammatory effects epidemics, the importance of finding a highly effective broad spectrum antiviral drug in combination with the anti-inflammatory activity is growing. Structurally similar derivatives of indolo[2,3-b]quinoxaline and indeno[1,2-b]quinoxalin-11-one exhibit a wide and partially similar spectrum of action, which makes them promising potential antiviral agents. These compounds were synthesized via substituted 1,2-diaminobenzenes and isatin (in case of 1) or ninhydrin (in case of 2) condensation and with no farther purification (indeno[quinoxalinone derivatives) or with washing with hot diluted alkali solution (to remove the major impurities of indoloquinoxaline derivatives). Thus, the aimed compounds were isolated as a mixture known, for a more detailed study of biological activity (especially in the case of ligandenzyme interactions), individual isomers should be investigated. This work is dedicated to the regio-isomeric composition investigation of synthesized indolo- and indenoquinoxalines and their separation. Considering minimal differences between isomeric compounds structure and chemical behavior, jnly chromatographic separation methods were required. Combination of poor solubility in low polar solvents and low separation effect for both of compound sets (indeno- and indoloquinoxalines) made column silica gel purification unacceptable. Indolo[2,3-b]quinoxaline isomers were separated by preparative TLC method using chloroform and ethyl-acetate as eluent. Separation was confirmed by UV-HPLC and MS-MS-UPLC methods. Indeno[1,2-b]quinoxalin-11-one derivatives were not separated in preparative quantities using silica gel column/thin layer methods.

A tunable metamaterial-based linear-to-circular polarization converter regulated solid state plasma in S-band

As the most widely used band in wireless communication systems, S-band is often used in many military and civil fields. In this paper, with the aid of the reconfigurability realized by the solid state plasma (SSP), a tunable metamaterial-based polarization converter is proposed and theoretically investigated. Through the premeditated excitation of the SSP resonators in the specific region, the linear-to-circular polarization conversions with two different operating states can be realized and switched to each other. The numerical results show that the polarization converter can obtain circularly polarized waves in two separate bands (2.15–2.63 GHz and 3.18–3.71 GHz) when our design is in State I, and the dual operating bands expands and merges into a consecutive ultra-wideband range (2.04–3.67 GHz) when our design is switched to State II. The total tunable working range of the presented polarization converter can essentially cover the whole S-band and the phenomenon of the isolation and fusion of the operating band possesses great potential application value in the fields of radar radomes, polarization separation, electromagnetic shielding, and so on.

On the realization and analysis of circular harmonic transforms for feature detection

Circular-harmonic spectra are a compact representation of local image features in two dimensions. It is well known that the computational complexity of such transforms is greatly reduced when polar separability is exploited in steerable filter-banks. Further simplifications are possible when Cartesian separability is incorporated using the radial apodization (i.e. weight, window, or taper) described here, as a consequence of the Laguerre/Hermite correspondence over polar/Cartesian coordinates. The chosen form also mitigates undesirable discretization artefacts due to angular aliasing. The possible utility of circular-harmonic spectra for the description of simple features is illustrated using real data from an airborne electro-optic sensor. The spectrum is deployed in a test-statistic to detect and characterize corners of arbitrary angle and orientation (i.e. wedges). The test-statistic considers uncertainty due to finite sampling and clutter/noise.

Different polarization definitions in same-sign WW scattering at the LHC

We study the polarization of positively charged W's in the scattering of massive electroweak bosons at hadron colliders. We rely on the separation of weak boson polarizations in the gauge-invariant, doubly-resonant part of the amplitude in Monte Carlo simulations. Polarizations depend on the reference frame in which they are defined. We discuss the change in polarization fractions and in kinematic distributions arising from defining polarization vectors in two different reference frames which have been employed in recent experimental analyses.

The wide-angle broadband absorption and polarization separation in the one-dimensional magnetized ferrite photonic crystals arranged by the Dodecanacci sequence under the transverse magnetization configuration

Utilizing the transfer matrix method, a multifunctional infrared device possessing the properties of the wide-angle broadband absorption and the polarization separation based on the one-dimensional (1-D) magnetized ferrite photonic crystals (MFPCs) arranged by the Dodecanacci sequence is designed theoretically under the modulation of the external magnetic field. The magneto-optical effect generated in the proposed MFPCs gives birth to the ultra-broadband absorption regions under the transverse electric (TE) mode, one runs at 16.22 THz –30.89 THz and the other covers at 33.52 THz–70.00 THz. The mechanism of the wide-angle (at most 80.89° for TE mode) absorption is analyzed by the interference cancellation condition. Moreover, owing to the different effective permeabilities of the MFPCs under the two polarization modes, the propagation behaviors of the electromagnetic (EM) wave are diverse which present the absorption features under the TE mode and show the transmission properties under the transverse magnetic (TM) mode in the structure. Compared with the periodic and Thue-Morse structures, the complex symmetry of the Dodecanacci sequence makes the absorption features of the MFPCs superior to that of the former. Besides, the influences of the magnetic field intensity and the dielectrics’ thicknesses on the angle-insensitive absorption and polarization separation characteristics are discussed explicitly. This research provides meaningful guidance for the modulation and absorption of the infrared light wave and the design of the multifunctional magnetically tunable optoelectric device.

Biodiesel production from engineered sugarcane lipids under uncertain feedstock compositions: Process design and techno-economic analysis

In this study, different process schemes were designed and evaluated for biodiesel production from engineered cane lipids with uncertain fatty acid compositions. Four different process schemes were compared under (i) thermal glycerolysis and (ii) enzymatic glycerolysis approaches. These schemes were based on the biodiesel yield and economic indicators such as the net present value (NPV) and the minimum selling price (MSP) of biodiesel. A scheme with polar lipid separation under thermal glycerolysis resulted in the maximum NPV ($96.5 million) and minimum MSP ($1107/ton biodiesel), respectively. Through local sensitivity analysis, it was concluded that the cane lipid percentage is the most significant factor influencing process economics. A conjoint analysis of the lipid procurement price and cane lipid percent suggested that 15% cane lipids with a low lipid procurement price ($0.536/kg) results in a positive NPV. When the cane lipid price is higher (>$0.80/kg), a 20% lipid content should be considered to achieve a positive NPV. At 20% cane lipids, the worst-case and best-case scenarios were evaluated by analyzing the interplay of the three most important parameters, The best-case scenario revealed that the minimum NPV under any process scheme could yield more than $100 million (or MSP: $0.80/L), and the worst-case analysis showed that losses incurred by the plant could be as high as $80 million (MSP: $1.36/L). A Monte Carlo simulation indicated that there is a 70% chance of the plant being profitable (NPV > 0).

Atomistic modeling and rational design of optothermal tweezers for targeted applications.

Optical manipulation of micro/nanoscale objects is of importance in life sciences, colloidal science, and nanotechnology. Optothermal tweezers exhibit superior manipulation capability at low optical intensity. However, our implicit understanding of the working mechanism has limited the further applications and innovations of optothermal tweezers. Herein, we present an atomistic view of opto-thermo-electro-mechanic coupling in optothermal tweezers, which enables us to rationally design the tweezers for optimum performance in targeted applications. Specifically, we have revealed that the non-uniform temperature distribution induces water polarization and charge separation, which creates the thermoelectric field dominating the optothermal trapping. We further design experiments to systematically verify our atomistic simulations. Guided by our new model, we develop new types of optothermal tweezers of high performance using low-concentrated electrolytes. Moreover, we demonstrate the use of new tweezers in opto-thermophoretic separation of colloidal particles of the same size based on the difference in their surface charge, which has been challenging for conventional optical tweezers. With the atomistic understanding that enables the performance optimization and function expansion, optothermal tweezers will further their impacts.

Power splitter and TE-TM polarization separator based on magneto-photonic crystal fiber

Specifically, this work aims to achieve a power splitter and polarization separator of a guided light, basing on magnetic properties such as gyrotropy, mode coupling and optimization of geometric parameters of a magneto-photonic fiber. This fiber which makes it possible to split and separate the polarizations is characterized by the opto-geometric optimization of an Y junction based on magnetic fluid in a silicon dioxide photonic crystal fiber, able to separate combination of two guided modes TE/TM, into two waves of the same amplitude and in phase between them, an incoming light wave which arrives at the Y-branch input of the fiber.

Picosecond Kerr-gated Raman spectroscopy for measurements in sooty and PAH rich hydrocarbon flames

The picosecond optical Kerr gate is an effective method for the separation of long-lived laser induced interference from instantaneous Raman scattering. In this paper, an application of the Kerr-gated Raman spectroscopy in combustion environment was demonstrated. The fast gating provided by a Kerr effect based optical shutter extends Raman spectroscopy measurements to sooty flames and flames rich in polycyclic aromatic hydrocarbons. The optical setup of the Kerr gate is described in detail and the gating time, efficiency and spatial uniformity of the ultrafast shutter are reported. To demonstrate the concept, the Kerr-gated Raman spectroscopy was applied in a laminar CH4/air diffusion flame to evaluate the capability to extract a Raman spectrum under different interference levels. In the region deemed inaccessible with µs-gated Raman spectroscopy, the laser induced interference was effectively suppressed by the Kerr gate. A test was also conducted in a C2H4/air premixed flame to explore the limitation of the Kerr-gated Raman technique. The result shows that after combining with polarization separation, Raman spectra can be extracted from locations with 65 ppb soot volume fraction.

The antenna system with signal polarization separation

The results of the study of the electrical characteristics of the waveguide-coaxial structure of the polarization separator (orthoplexer) loaded by the waveguide irradiator under the influence of harmonic radiation in the frequency band and pulse signal are presented. The antenna system is designed to study partially-non-reciprocal backscattering of electromagnetic waves.

Analysis of the features of a multifunctional device based on the regulation of the magnetic field in one-dimensional photonic crystals containing only plasma with a novel quasi-periodic structure

In this paper, the features of a multifunctional device that are realized by one-dimensional magnetized plasma photonic crystals (MPPCs) containing only the plasma regulated by the external magnetic field in an innovative quasi-periodic arrangement are studied by the transfer matrix method, which possesses the characteristics of the omnidirectional bandgap (OBG), nonreciprocity (NR), and polarization separation (PS). The effects of the magnetic field and other physical parameters including the plasma frequency and incident angle on those three properties are illustrated, respectively. The computed results demonstrate that, with the gradually increasing magnetic field, the performances of OBG and NR apparently deteriorate while the PS region expands ideally. Meanwhile, the greater presentations of OBG and PS can be gotten with the proper rise of the plasma frequency. Nevertheless, the higher the plasma frequency is, the worse the quality of NR will be observed. Furthermore, an appropriate incident angle also plays a crucial part in the display of NR and PS for the proposed structure, and these properties can be enhanced well with a larger incident angle. This new kind of MPPC has potential application in designing tunable and multifunctional optical instruments.

Fine Filament Structure of a Quiescent Solar Prominence

A theoretical model of a cold and dense isolated solar prominence is presented. The thermodynamic parameters of a filament (gas pressure, density and temperature) are calculated from a specified magnetic field structure. The filament lies above the photospheric polarization separation line and its magnetic field falls off rapidly with distance from the axis, so that the total electric current along the axis of the filament equals zero. The prominence has a helical magnetic field structure divided into separate thin filaments. The density and temperature distributions of the prominence derived from the equilibrium conditions for this kind of magnetic field correspond well to the known observed parameters.

Cell Distribution within Yeast Colonies and Colony Biofilms: How Structure Develops.

Multicellular structures formed by yeasts and other microbes are valuable models for investigating the processes of cell–cell interaction and pattern formation, as well as cell signaling and differentiation. These processes are essential for the organization and development of diverse microbial communities that are important in everyday life. Two major types of multicellular structures are formed by yeast Saccharomyces cerevisiae on semisolid agar. These are colonies formed by laboratory or domesticated strains and structured colony biofilms formed by wild strains. These structures differ in spatiotemporal organization and cellular differentiation. Using state-of-the-art microscopy and mutant analysis, we investigated the distribution of cells within colonies and colony biofilms and the involvement of specific processes therein. We show that prominent differences between colony and biofilm structure are determined during early stages of development and are associated with the different distribution of growing cells. Two distinct cell distribution patterns were identified—the zebra-type and the leopard-type, which are genetically determined. The role of Flo11p in cell adhesion and extracellular matrix production is essential for leopard-type distribution, because FLO11 deletion triggers the switch to zebra-type cell distribution. However, both types of cell organization are independent of cell budding polarity and cell separation as determined using respective mutants.

Carbon Nanotube (CNT) Stationary Phase for Micro Gas Chromatograph Columns

Introduction Microfabricated gas chromatography systems based upon MEMS fabrication technology are under development for portable chemical vapor analysis and chemical detection. In particular, Sandia National Laboratories has pioneered development of these miniature systems (1). Current methods for coating microfabricated gas chromatography columns are based upon deposition from a saturated mixture of siloxanes in a solvent, which are adapted from techniques developed for coating of open-tubular capillary columns (2). This static method is more successful with silica open tube columns which have a uniform cross-section area, however in a microfabricated column, a rectangular cross-section is produced in the channel. The square corners tend to have a thicker layer of material deposited using this process and hence these thicker layers provide a different retention time for the analytes which results in peak broadening and reduction in resolution and peak capacity of the column. Alternative stationary phases have been investigated (3), and using chemical vapor deposition (CVD) they can be grown with uniform thickness, for example carbon nanotubes (CNTs) (4) The CNTs have high surface area and are stable at high temperatures. Method A silicon substrate is used for the fabrication of a microfabricated spiral column, 6m in length using standard photolithography and deep reactive ion etching fabrication processes (5). An ultra-thin layer of iron catalyst is deposited by sputtering into the etched silicon channel. Using a Black Magic plasma enhanced CVD growth a layer of CNTs are formed thickness 0.5 to 1 micrometer. Figure 1 shows an SEM micrograph of the deposited CNTs layer which coats the sides of channel and base with uniform thickness. Next a layer of gold is deposited for eutectic bonding of the silicon lid in order to enclose the channel making the column. Finally high temperature annealing is carried out at 450 oC to increase bond strength. Results The column is mounted inside a commercial Agilent 6890 GC system oven with a short length of guard column, approximately 0.5m length, connect between the split injector and the flame ionization detector. A liquid injection of three compounds, hexane, octane and decane, volume of 0.02uL, was carried out with a 100:1 split and injector temperature of 275°C. The helium carrier gas flow rate was 0.1 ml/min. A typical chromatogram is shown in Figure 2. The McReynolds probes for polarity were also injected, and the Kovats indices were evaluated for comparison with OV-1 (Ohio Valley, OH) polymer stationary phase. Conclusions The use of CNT’s for a stationary phase may offer some advantages with micro-GC column fabrication because the quality of the layer can be inspected prior to bonding. We can observe the low polarity of the CNT stationary phase compared to the poly-siloxane However, it may be possible to chemically functionalize the surface for the CNTs for more polar compound separation and analysis.

Polarization Analysis of Gas Diffusion Electrode with Different Fabrication Parameters in Metal–Air Batteries

The gas diffusion electrode (GDE) represents the most significant component in metal–air batteries (MABs). It is essential to understand the underlying behaviors of GDE and optimize its performance. Herein, a polarization separation method from total polarization curve to single activation, ohmic, and mass transport polarizations of GDE in MABs is proposed for the first time, which is then applied in the investigation of detailed polarization behaviors of the GDE by changing the fabrication parameters. As the polytetrafluoroethylene contents in the catalyst and gas diffusion layers and pressing pressure are adjusted, hydrophobicity, porosity, coverage, and thickness are changed to influence the performance of GDE. Through this analysis, a detailed understanding of the structure–performance relationship of GDE is achieved to improve the electrode design, architecture, and fabrication.

Dielectric resonator based multiport antenna system with multi-diversity and built-in decoupling mechanism

In this article, an eight-element, sixteen port dielectric resonator (DR) based double sided multi-port antenna is presented, which supports the unique dual-directional pattern diversity feature. The orientation of the double-sided dielectric resonator antenna (DRA) is one of the novel features of the proposed antenna. Four cylindrical dielectric resonator antennas (cDRAs) are placed at the top of the substrate, and each top cDRA is excited with the help of two orthogonally placed coplanar waveguide (CPW) fed conformal microstrip lines. In the same manner, the other four cDRAs are placed at the bottom of the substrate, and each cDRA is fed via conformal strip lines. The proposed antenna works in between 5.4 GHz and 6.0 GHz. Several isolation techniques (polarization diversity, pattern diversity, and separation between the antenna elements) within the antenna elements are approached to improve the antenna performance. As a result, without using any isolation improvement technique, the proposed structure achieves 17 dB of isolation between the ports, which makes the proposed radiator unique. The similarity in simulated and experimental outcomes confirms that the designed 16-port multi-port antenna system is suitable for Wireless LAN applications.

Preparation of PZT Thin Film/Ni Particle Composite Magnetoelectric Materials

Lead Zirconium Titanate (PZT) thin film magnetoelectric materials have widely application in controllable sensing and tuneable microwave devices. The PZT film ferroelectric domain was designingly distributed and reversed by using the piezoelectric power response technique. The magnetoelectric composite of PZT film and Ni particle was prepared by the ferroelectric spontaneous polarization separation photogenerated carrier, reduction Ni atom deposition on the PZT thin film ferroelectric positive domain region. The optical morphology, XRD and SEM morphology show that the Ni particles deposited on the PZT film increase first and then become more uniform with the extension of deposition time. The deposition time closely relate to the deposition effect of Ni particles, and the deposition effect is more obvious with time. After the photo-deposition, the surface particles of the unexcited domain film are scattered after the photo-deposition, and the shape of the deposited particles region in which the Ni particles are reduced is substantially similar to the write-domain pattern, and the particle diameter is about 10-20 nm.

Separation of 4C-Substituted Pyrrolidin-2-One Derivatives on Polysaccharide-Based Coated Chiral Stationary Phases

Fifteen structurally different 4C-substituted pyrrolidin-2-one derivatives were used as model analytes for investigation of enantioseparation abilities on six commercially available polysaccharide-based coated chiral stationary phases (cellulose tris (3,5-dimethylphenylcarbamate), cellulose tris (3-chloro-4-methylphenylcarbamate), cellulose tris (4-methylbenzoate), cellulose tris (4-chloro-3-methylphenylcarbamate), amylose tris (3,5-dimethylphenylcarbamate), and amylose tris (5-chloro-2-methylphenylcarbamate) under normal phase and polar organic separation modes. Influence of stationary and mobile phase type on resolution and elution order of enantiomers was studied. Results showed that the polysaccharide backbone of the stationary phase (amylose and cellulose) has a significant impact on chiral recognition, and the best separation was observed on amylose-based chiral stationary phases. It was established that steric effects play an important role on 4C-substituted pyrrolidin-2-one derivative resolution on polysaccharide-based chiral columns. Nature of alcohol in the mobile phase was also an important factor contributing not only to retention but also resolution. Although the use of the normal phase mode seems more beneficial, in certain cases, polar organic mode may increase the number of separated pairs of enantiomers.

Effect of Rare-Earth Ions on an Electric Polarization Induced by the Phase Separation Domains in RMn2O5 (R = Er, Tb)

The effect of rare-earth ions (R = Er^{3+}, Tb^{3+}) with strong spin-orbit coupling on the dielectric properties and the electric polarization induced by local polar phase separation domains in RMn_2O_5 multiferroics has been studied. These parameters were found to be qualitatively distinguished from those studied before in GdMn_2O_5, in which Gd^{3+} ion in the ground ^8S_{7/2} state is weakly bounded with the lattice. It is shown that the properties of the polar phase separation domains, which form in the subsystem of Mn^{3+} and Mn^{4+} ions, are substantially dependent on the values of crystal fields, in which these domains exist.

Влияние редкоземельных ионов на электрическую поляризацию, индуцированную областями фазового расслоения в RMn-=SUB=-2-=/SUB=-O-=SUB=-5-=/SUB=- (R=Er, Tb)

The effect of rare-earth ions (R = Er^{3+}, Tb^{3+}) with a strong spin-orbit coupling on the dielectric properties and electric polarization induced by the local polar phase separation domains in RMn_2O_5 multiferroics is studied. A qualitative difference between these parameters and those studied previously in GdMn_2O_5 was discovered, in which the Gd^{3+} ion in the ^8S_{7/2} ground state is weakly coupled to the lattice. It has been shown that the properties of the polar phase separation that arise in the subsystem of Mn^{3+} and Mn^{4+} ions due to the finite probability of electron tunneling between these ions of different valencies substantially depend on the magnitudes of the crystal fields in which these domains are located. Authors on English: B.Kh. Khannanov, E.I. Golovenchits, V.A. Sanina