Range Of Sweep Research Articles

Rheological Study on Blend Solutions of Non-mulberry Silk Fibroin and Gelatin Biopolymers

In current research work, we have studied the blending effect of non-mulberry silk fibroin (10% weight/volume basis) and gelatin (20% weight/volume basis) in formic acid. Several blends as SF10G0, SF2G8, SF3G7, SF5G5 and SF0G10 have been made and their rheological behaviour was investigated. The blend solutions were subjected to a steady shear rheological study in the variety of range of shear rates, namely 0.01–500 sec-1 and the viscosities of blend solutions were noticed to decrease in comparison to pure silk solution. The frequency sweep was employed in dynamic rheological tests to determine complex viscosity of these solutions from range of angular sweep 0.1–100 rad/sec. The consistent shear-thinning behaviour was noted for all the blends. The difference in numerical values of shear and complex viscosities indicated disobedience of Cox-Merz rule. Such analysis can be utilised for tailoring the properties of solution prior to processing them to create a versatile range of materials.

Negative differential resistance in Si nanostructure: role of interface traps

Negative differential resistance (NDR) has been observed in I-V characteristics measured between two aluminum (Al) pads deposited on a layer containing Silicon nanostructures. This feature has been observed for suitable bias range and specific direction of voltage sweep. NDR has been found to show up within a specific range of lower and upper threshold voltages for each of the samples studied in this work. The amount of NDR has been found to depend on voltage scan rate and bias range. The observed phenomena have been explained using the dynamics of charge trapping and detrapping at the surface/interface defect states present at the boundary of the nanostructured silicon and the oxide layer. An equivalent circuit designed by incorporation of suitable resistance and capacitance representing the trap assisted charge transport within the aluminum-Silicon nanostructure junctions has produced similar I-V characteristics as obtained in the experimental results. Repeatability of NDR shows the potential of the device to be used in oscillators.

В’язкопружні властивості суспензій кукурудзяного крохмалю на електрохімічно активованій воді

Water has the ability to regulate the physiological processes of the human body, which characterizes its biological activity. Macro- and microelements, vitamins, amino acids, etc. enter the body with water and food. Nowadays, the issue of the influence of activated water on the structure and course of processes in food systems with its content is insufficiently covered in scientific sources, which is a perspective for research. Due to its physical and chemical properties, activated water can influence the quality indicators and structure of products containing it. Thus, in the recipes of many products, corn starch is used as an emulsifier. The purpose of the research was to determine the effect of activated water on the viscospringy indicators of corn starch suspensions. Activated water significantly affects the elastic and viscous properties of corn starch suspensions. The storage mo dulus of the samples on the catholyte and anolyte at 25 °С had a significantly higher value than the shear modulus of the control sample at zero frequency. This indicator increased with increasing frequency. The loss modulus of all samples of starch pastes increased with an increase in the scanning frequency, however, at the pasteurization temperature, the increase occurred less intensively: in the frеquency range of 0.1—10 Hz for the sample on tap water, the studied indicator increased by 63.6±0.5 times, on the catholyte and anolytes — 41.5±0.5 and 43.7±0.5 times, respectively. At 25 °С, this indicator increased by 41.7±0.5; 22.1±0.5 and 23.1±0.5 times. Over the entire range of the frequency sweep, the complex shear stress of suspensions increased, and the control indicators at 25 °С and at 68 °С were lower than the corresponding values for suspensions on catholyte and anolyte. Thus, activated water affects the rheological indicators of starch suspensions, which in turn will be reflected in the structural and mechanical properties and consistency of products containing such suspensions in the formulation.

High Sensing Accuracy Realisation With Millimetre/Sub-Millimetre Resolution in Optical Frequency Domain Reflectometer

By effectively suppressing the nonlinear sweep noise and random range of wavelength sweep in the optical frequency domain reflectometer, the theoretical spatial resolution and uniform sweep distribution are delivered for high sensing accuracy. A strain accuracy of ±0.51 μϵ is realised with a 5 mm sensing resolution, while the accuracy is ±5.89 μϵ with a 1 mm sensing resolution. Theoretical limitation between the strain accuracy and sensing resolution is further studied for the sub-millimetre resolution sensing. It is found that signal to noise ratio and frequency bandwidth of the calculated cross-correlation are critical factors in measuring accuracy. Increasing the sweep range can provide a better spatial frequency step for a high signal to noise ratio in the cross-correlation. With a 130 nm sweep range, the measurement accuracy is limited to ±19.31 μϵ with a 0.5 mm sensing resolution. Besides, for the long-distance sensing of 104 m, the measurement accuracy is ±8.72 μϵ with a 1 mm sensing resolution.

Interrelating Grain Hardness Index of Wheat with Physicochemical and Structural Properties of Starch Extracted Therefrom.

To investigate the physicochemical, structural, and rheological characteristics of starch from wheat cultivars varying in grain hardness index employed in making jiuqu and to interrelate grain hardness index with physicochemical and structural properties of starch. Starch extracted therefrom was investigated for structural and physicochemical properties. Starch granules showed relatively wide granule size distribution; large size granules showed lenticular shapes while medium and small size granules exhibited spherical or irregular shapes. Starch from wheat with a lower grain hardness index exhibited a relatively higher degree of crystallinity. Chain-length profiles of amylopectin showed distinct differences; among the fractions of fa, fb1, fb2, and fb3 representing the weight-based chain-length proportions in amylopectin, the fa fractions ranged from 19.7% to 21.6%, the fb1 fractions ranged from 44.4% to 45.6%, the fb2 fractions ranged from 16.2% to 17.0%, and the fb3 fractions ranged from 16.1% to 18.8%, respectively. To, Tp, Tc, and ∆H of starch ranged from 57.8 to 59.7 °C, 61.9 to 64.2 °C, 67.4 to 69.8 °C, and 11.9 to 12.7 J/g, respectively. Peak viscosity, hot pasting viscosity, cool pasting viscosity, breakdown, and setback of starch ranged from 127 to 221 RVU, 77 to 106 RVU, 217 to 324 RVU, 44 to 116 RVU, and 137 to 218 RVU, respectively. Both G’ and G” increased in the frequency range of 0.628 to 125.6 rad/s; the wheat starch gels were more solid-like during the whole range of frequency sweep.

Preparation of NADPH-Tcpp Immobilized Electrode and Photoinduced Oxidation

The development of new strategies for converting light source to chemical energy or useful compounds have been required. In order to accomplish light-driven reaction, photosensitizer and enzymes are utilized as a component of reaction system. Moreover, the light-driven reaction prepared on solid phase is considered to be useful device on the system.This study shows that photoinduced oxidation system on ITO electrode with porphyrin is prepared and some oxidase reaction by light irradiation occurs. A photoexcited state of porphyrins are able to accept electrons from oxidase via mediator such as NADPH, while an electron of the LUMO is donate to ITO electrode on which the porphyrin is immobilized. Therefore, photoinduced oxidation occur on ITO electrode.NADPH-porphyrin immobilized ITO electrode was prepared and photoanodic reaction, photoinduced electron transfer to ITO electrode, is carried out. Firstly, redox cycle of NADPH immobilized electrode was investigated. Basically, immobilized NADPH redox reaction is hard to observe without excess over potentials, so that NADPH is immobilized on Au electrode by covalently binding due to decrease in an interfacial resistance between electrode surface and NADPH. Enzymatic reaction using NADPH immobilized electrode was carried out and investigated that NADPH monolayer mediate electron from enzymes.In addition, NADPH-porphyrin immobilized ITO electrode was prepared and photoinduced oxidation with malate dehydrogenase was carried out.NADPH monolayer on Au electrode was prepared as follows. Au electrode surface was modified with a self-assembled monolayer (SAM) of α-Lipoic acid, and 3-amino boronic acid was covalently linked to the carboxyl group of the α-Lipoic acid SAM. NADPH was covalently bound to the boronic acid, which was immobilized on α-Lipoic acid SAM.In the case of the photoinduced oxidation experiment, ITO electrode on which NADPH-TCPP diads was absorbed (NADPH-TCPP-ITO). TCPP (tetrakis(4-carboxyphenyl)porphyrin) was used as a photosensitizer. ITO electrode was silanized with APTES (3-Aminopropyltriethoxysilane). The amino-functionalized layer on the ITO electrode was modified with TCPP and then 1,2-diamino ethane was bound to carboxy group of TCPP. Finally, NADPH was covalently bound to the amine group of diamino ethane-TCPP monolayer on the ITO electrode.Experiment of photoinduced oxidation was carried out with NADPH-TCPP-ITO electrode. NADPH-TCPP-ITO electrode was immersed in 0.1M Tris buffer (pH9.0) containing 1 U of malate dehydrogenase (MDH) and 50 mM malic acid, and light irradiation under applied potential at 0 V. Current of this experiment was shown in Figure 2. Red line and black line show the current in the presence of MDH and in the absence of MDH, respectively. During light on 30 s~60 s, increase in current in the presence of MDH was observed, and the current was decrease immediately at the light off These result shows that photoinduced oxidation occurs, which NADPH donate electrons to HOMO of photoexcited state of TCPP and NADPH regenerate by the oxidation of malate with MDH. Otherwise, black line (in the absence of MDH) no current increase was observed during light on. Therefore, photoanodic reaction using MDH is able to proceed on NADPH-TCPP-ITO electrode.Figure 1 shows the cyclic voltammogram of NADPH immobilized Au electrode in 10 mM phosphate buffer (pH7.0). containing glucose dehydrogenase (GDH) and 10 mM glucose. CV was performed at 10 mV/s. Remarkably increase in anodic current was observed in the range of potential sweep. The increase in current indicate the catalytic current of GDH, which glucose was oxidized to gluconic acid Therefore, GDH in solution is able to access to the NADPH monolayer and occurs enzymatic reaction. Figure 1

High Pressure Effect on Structural and Electrochemical Properties of Anionic Redox-Based Lithium Transition Metal Oxides

Summary The richness of anionic redox chemistry in the solid state offers new opportunities and a possible paradigm shift in energy storage. The excess capacity that goes beyond conventional theoretical values is attributed to the anionic redox in Li-rich transition metal oxide cathodes for Li-ion batteries. Their electrochemical behavior is thermodynamically determined by structural evolution. To better understand the electrochemical dependence on structural factors, we have induced structural modifications in pristine and electrochemically activated Li1.144Ni0.136Co0.136Mn0.544O2 through high-pressure treatment. A unique cyclical change of structural reordering is observed in the anionic redox-activated material during operando pressure sweep, characterized by a periodic evolution of superlattice peak intensity in synchrotron X-ray diffraction patterns. During the structural reordering period, the bulk compressibility of the material decreases, even becoming negative. These insights elucidate the structural flexibility and metastability of anionic redox-based materials, which can undergo large compressions and structural modifications while delivering good electrochemical properties.

Composite Right/Left-Handed Leaky-Wave Antennas for Wide-Angle Beam Scanning With Flexibly Chosen Frequency Range

A composite right/left-handed (CRLH) leaky-wave antenna (LWA) can effectively scan the radiation beam from backward-to-forward direction. However, in most cases, a large range of frequency sweep is required to achieve a wide-angle beam scan, which could limit their applications. An in-depth study is conducted on an equivalent circuit model for a CRLH LWA unit cell to find the controlling parameters on the frequency sweeping range. A systematic design guideline is given for a CRLH LWA for a wide-angle beam scan in a flexibly chosen frequency range. It is shown that beam scanning by sweeping frequency in a target range can be achieved by systematically designing the unit cell parameters. To verify our approach, a novel CRLH unit cell is developed and used to design an LWA for a wide-angle beam scan in a narrow frequency range. Finally, the concept is validated through realization of the antenna and its measurement. The measured results show that the antenna prototype can scan its beam from −56° to +51° when frequency sweeps from 5.1 to 6.11 GHz (i.e., 18.02% of fractional bandwidth).

Multistate resistive switching characteristics of ZnO nanoparticles embedded polyvinylphenol device

Multistate resistive switching device was demonstrated with organic/inorganic nanocomposite layer of polyvinylphenol (PVP) embedded with zinc oxide nanoparticles (ZnO NPs). Both cap (ITO/ZnO NPs+PVP/Al) and crossbar (Pt/ZnO NPs+PVP/Al) device formats were examined, respectively. Extending range of voltage sweep could show adaptive memory effect, which could roughly emulate analog resistive switching device. In addition, potentiation and depression behaviors were also examined with 50 time consecutive pulsed bias (+2.0V and −2.0V respectively) having 10ms width measured at read voltage of −0.2V. A new possibility of analog resistive switching can be further pursued with the ZnO NPs+PVP nanocomposite.

A multispectral linear optical sweep source, based on tunable InGaN/GaN QW LEDs

Applications of multispectral sources are numerous. The previous forms of optical sources are continuously being replaced by efficient LEDs with an emphasis on III-nitrides, since it covers a very wide optical range. In this paper, we are proposing a multispectral linear optical sweep source, based on tunable InGaN/GaN QW LEDs. For linearization, a λ verses current curve of tunable InGaN/GaN QW LED, as obtained from our well established method of solution of Schrödinger and Poisson equations is considered as a model. The entire process of linearization is outlined in a simple form, for clear understanding. The linear sweep is so designed that it can be stopped at any λ,. i.e. color. Changing of the range of the spectral sweep through changes in the device parameters is pointed out. Procedures, necessary constituents and results are presented with suitable discussions. The multispectral ramp should be of much use for a wide range of applications.

Determination of suitable parameters for battery analysis by Electrochemical Impedance Spectroscopy

Electrochemical Impedance Spectroscopy (EIS) is one of the most powerful tools for the study of batteries. The applied AC current, range of frequency sweep, points per decade represented, length of the pause time after a change in the state of charge (SOC) and length of the pause time after a change in the ambient temperature must have suitable values to obtain useful results from EIS tests. A method to determine and optimize these parameters is presented in this paper. It is based on the limits imposed by the battery, the tests carried out, the instruments employed and the use of Kramers-Kronig relations. The method has been checked using two kinds of lithium batteries: a lithium iron phosphate (LFP) battery and a lithium cobalt oxide (LCO) battery.

A New Low-power, High-Q, Wide Tunable CMOS Active Inductor for RF Applications

ABSTRACTThis paper presents a new topology for realizing a single-ended inductor employing a minimum number of passive components. The active inductor achieves a high quality factor of 895 over a frequency range of 1700 MHz. Its self-resonance frequency is 5.5 GHz. The achieved range of sweep for inductance (L) varies from 3.55 to 26 nH. The circuit draws 0.5 mA current from 1.0-V supply and occupies an effective active area of 22 × 27.5 µm2, while the noise voltage is less than . The proposed inductor is designed and simulated in a 90-nm TSMC MS/RF CMOS process.

High precision and fast method for absolute distance measurement based on resampling technique used in FM continuous wave laser ranging

Frequency modulated continuous wave (FMCW) laser ranging is one of the most interesting techniques for precision distance metrology. It is a promising candidate for absolute distance measurement at large standoff distances (10 to 100 m) with high precision and accuracy, and no cooperation target is needed during the measuring process. How to improve the measurement resolution in practice has been the research focus of the FMCW laser ranging in recent years.FMCW laser ranging system uses the method which may convert the measurement of flight time to the frequency measurement, while the ranging resolution can be determined by the tuning range of the optical frequency sweep in theory. The main impact-factor that reduces the resolution is the tuning nonlinearity of the laser source, which may cause an amount of error points within the sampling signal. So a dual-interferometric FMCW laser ranging system is adopted in this paper. Compared to the traditional Michelson scheme, an assistant interferometer is added. The assistant interferometer has an all-fiber optical Mach-Zehnder configuration, and the delay distance is at least 2 times longer than OPD (optical path difference) of the main interferometer. Because it provides the reference length, the length of the fiber must remain unchanged. The interference signal is obtained on the photodetector. At the time points of every peak and bottom of the auxiliary interferometer signal, the beating signal from the main interferometer is re-sampled. The original signal is not the equal time intervals, while the re-sampled signal is the equal optical frequency intervals. Based on the property of the re-sampled signal, a method by splicing the re-sampled signal to optimize the signal processing is proposed, by which the tuning range of the laser source limitation can be broken and high precision can be easily obtained. Also, a simple high-speed measuring method is proposed.Based on all the above principles, the two-fiber optical frequency-modulated continuous wave laser ranging system is designed. The delay fiber in the FMCW laser ranging system is 40.8 m long, and the tuning speed and tuning range of the laser source are set to 10 nm/s and 40 nm respectively. Experiments show that the optimization method can effectively improve the measurement resolution and measuring efficiency; in the 26 measuring ranges, 50 m resolution can be easily obtained and the error is less than 100 m.

Precise beam energy measurement using resonant spin depolarization in the SOLEIL storage ring

The average electron beam energy for the operational mode of 400mA in 416 bunches in the SOLEIL storage ring was measured to be 2.73724±0.00016GeV with an accuracy of 5.9×10−5 using the method of resonant spin depolarization (RSD). A Touschek-dominated electron beam was excited using a shaker magnet, and the beam polarization and depolarization were monitored using the change in beam lifetime and beam loss rate. To establish the primary condition that is required to perform energy measurement using the RSD method, the radiative beam polarization was first simulated using the SLIM beam dynamics code and then measured using the relative increase of beam lifetime for a Touschek-dominated electron beam. With a fast frequency sweep rate, the main depolarization resonance to be used to extract the beam energy, along with sidebands within the range of frequency sweep, was identified during our first trials. Sweeping the frequency of the excitation field around the main resonance with a slower frequency sweep rate, the beam energy measurement accuracy was increased from 1.7×10−4 to 5.9×10−5. Finally, the effects of closed orbit distortions on the radiative polarization and measured energy accuracy are discussed.

Formation of Biomimetic Membrane Rafts on Bare and Modified Gold

Lipid domains are essential functional entities of biological membranes, therefore lipid bilayers containing liquid disordered/liquid ordered (lipid rafts) phase coexistence are improved biomimetic systems. Moreover, supported lipid bilayers (SLB) of such ternary lipid mixtures formed on gold are promising interfaces for biosensing purposes. However, gold’s hydrophobic nature has been an obstacle for direct deposition, and most studies rely on previous modification of its surface. In addition, the formation and properties of lipid domains in these systems only raised attention very recently. In this work, ternary lipid mixtures (e.g. DOPC/DPPC/Cholesterol (2:2:1 molar ratio)) were deposited on gold, either bare or modified with hydrophilic self-assembled monolayers (SAMs) of 11-mercaptoundecanoic-acid (MUA) and cystein, which display distinct packing density and organization. Atomic force microscopy was used to study the topography of the lipid films at the nanoscale, allowing the first reported observation of well-organized raft-containing SLB on unmodified gold. This was achieved under optimized conditions, as changing slightly buffer composition may lead e.g. to the formation of tubular structures. Coverage and continuity of SLB were addressed by ellipsometry and cyclic voltammetry, taking advantage of gold optical/electrical properties. The cyclic voltammograms of ferricyanide redox process suggest the presence of continuous bilayers with small pores. The bilayer thicknesses, 4-5nm, estimated by ellipsometry were further confirmed by force spectroscopy. The raft-containing bilayer is stable over a wide range of potential sweep, enabling the development of new lipid raft-based biosensing interfaces. Planar and continuous SLB could be also prepared onto gold modified electrodes. In the case of a short cystein SAM, pronounced decrease of the redox process intensity was observed after lipid deposition revealing a high coverage of the modified gold surface.Acknowledgements: SFRH/BD/64442/2009, PTDC/QUI/66612/2006, PEst-OE/QUI/UI0612/2011 and Ciencia2007 (FCT Portugal).

Biomimetic membrane rafts stably supported on unmodified gold

The formation of lipid bilayers on bare gold containing gel/fluid and liquid disordered/liquid ordered domains (lipid rafts), essential for the functioning of biological membranes, is reported here for the first time. Such binary and ternary lipid mixtures deposited on gold are improved biomimetic platforms. However, gold's hydrophobic nature has been an obstacle for direct deposition, and most studies rely on previous modification of its surface. In this work, lipid mixtures were deposited under different experimental conditions, including those commonly used for other solid supports such as mica, which are known to yield planar and organized bilayers. Atomic force microscopy imaging was used to study the topography of the lipid films at the nanoscale. The coverage, continuity and packing were addressed by ellipsometry and cyclic voltammetry, taking advantage of gold optical/electrical properties. A high quality bilayer displaying well organized lipid rafts is obtained by small or large unilamellar vesicle fusion in 10 mM Hepes buffer without added salt, while the presence of NaCl inhibits the formation of a lipid bilayer and leads to tubular structures. The raft-containing bilayer is stable over a wide range of potential sweep, enabling the development of new lipid raft based biosensing interfaces.

Characterization of gold nanoparticle pentacene memory device with polymer dielectric layer

We report on the electrical behavior of gold nanoparticles (Au NPs) intervened metal-pentacene-insulator-semiconductor structures. The structure adopts polyvinyl alcohol (PVA) and pentacene as gate insulator and semiconductor, respectively. On the PVA (250 nm) film which was spin-coated and UV cross-linked, 3-aminopropyl triethoxysilane was functionalized for self assembling of the Au NPs monolayer. The devices exhibited clockwise hysteresis in their capacitance-voltage characteristics, with a memory window depending on the range of the voltage sweep. A relatively large memory window of about 4.7 V, which was deduced from control devices, was achieved with voltage sweep of (−/+)7 V. Formation of the monolayered Au NPs was confirmed by field effect scanning electron microscopy and atomic force microscopy.

Population transfer for signal enhancement in pulsed EPR experiments on half integer high spin systems

High resolution pulse EPR techniques applied to half integer high spin systems, such as Mn(2+) (S = 5/2), usually focus only on the central |-1/2--> |1/2 transition. The reason is that at high fields, where the zero field splitting is considerably smaller than the Zeeman interaction, the spectrum of this transition is intense and narrow. However, because the experiments are carried out at low temperatures, the low lying levels are heavily populated and the signal of the central transition is nevertheless diminished. This, in turn affects the sensitivity of the pulse EPR technique applied. A transfer of populations from the lower lying levels, which for Mn(2+) are the |-3/2 and |-5/2 levels, to the |-1/2 level will therefore increase the sensitivity. Here we describe such an experiment, where a rapid magnetic field sweep over the |-3/2--> |-1/2 sub-spectrum is carried out, concomitantly with a low power microwave (mw) irradiation, which results in population inversion. After this sweep any pulsed EPR sequence can be applied to the central transition that now has a population difference that deviates from the equilibrium value. The feasibility of the experiment is demonstrated at W-band (95 GHz) on Mn(2+) doped in MgO for echo-detected EPR measurements and the dependence of the signal enhancement on the rate and range of the magnetic field sweep and on the mw power is described. The results are then accounted for theoretically by considering a simple fictitious spin 1/2 system. In addition, preliminary enhanced (55)Mn pulse ENDOR electron nuclear double resonance (ENDOR) spectra are presented.

Memory effects in MIS structures based on silicon and polymethylmethacrylate with nanoparticle charge-storage elements

We report on the electrical behaviour of metal–insulator–semiconductor (MIS) structures fabricated on p-type silicon substrates and using polymethylmethacrylate (PMMA) as the dielectric. Gold nanoparticles, single-wall carbon nanotubes and C 60, deposited at room temperature, were used as charge-storage elements. In all cases, the MIS devices containing the nanoparticles exhibited hysteresis in their capacitance versus voltage characteristics, with a memory window depending on the range of the voltage sweep. This hysteresis was attributed to the charging and discharging of the nanoparticles from the gate electrode. A relatively large memory window of about 2.2 V was achieved by scanning the applied voltage of an Al/PMMA/C 60/SiO 2/Si structure between 4 and −4 V. Gold nanoparticle-based memory devices produced the best charge retention behaviour compared to the other MIS structures investigated.

Memory effects in hybrid silicon-metallic nanoparticle-organic thin film structures

We report on the electrical behaviour of metal–insulator–semiconductor (MIS) structures fabricated on silicon substrates and using organic thin films as the dielectric layers. These insulating thin films were produced by different methods, including spin-coating (polymethylmethacrylate), thermal evaporation (pentacene) and Langmuir–Blodgett deposition (cadmium arachidate). Gold nanoparticles, deposited at room temperature by chemical self-assembly, were used as charge storage elements. In all cases, the MIS devices containing the nanoparticles exhibited hysteresis in their capacitance versus voltage characteristics, with a memory window depending on the range of the voltage sweep. This hysteresis was attributed to the charging and discharging of the nanoparticles from the gate electrode. A maximum memory window of 2.5 V was achieved by scanning the applied voltage of an Al/pentacene/Au nanoparticle/SiO 2/p-Si structure between 9 and −9 V.