Sweep Curves Research Articles

Interpolation linearization predistortion technology for FMCW LiDAR.

Frequency-modulated continuous-wave (FMCW) laser ranging technology is an important development direction of light detection and ranging (LiDAR) for the future. It has the advantages of high ranging accuracy, high resolution, wide range, and no ranging blind zone. A distributed feedback laser can be used as a high-quality light source in FMCW laser ranging systems because of its wide frequency modulation range, simple frequency modulation mode, and small package. Aiming at the nonlinear problem of the laser in the frequency modulation process, we present a novel, to our knowledge, predistortion algorithm based on interpolation linear fitting to enhance the linearity of the FMCW laser for LiDAR systems. The sweeping frequency curve of the laser is obtained using the Hilbert transform, and then the sweeping frequency curve is segmented and linearly fitted to calculate the interpolated driving current signals corresponding to linear frequency changes. Using this method, we achieved a nonlinearity error lower than 1e-7 for the swept-frequency signal and demonstrated that the ranging error is less than ±5c m at a distance of 100m in the FMCW system. In addition, we also demonstrated a 3D static object point cloud with high imaging quality. Compared with the iterative predistortion algorithm based on the function fitting, this method avoids fitting errors at the inflection points of the triangular swept-frequency signal and the complexity of multiple iterative calculations. It enables rapid generation of pre-distorted swept-frequency signals, making it particularly suitable for real-time applications of automotive LiDAR systems.

Rheology of paste-like food inks for 3D printing: Effects of nutrient and water content

This research delves into understanding the effects of composition on the rheological response of multi-component food inks for 3D food printing. Accordingly, the motivation is to decouple the nutrient and water content effects on the rheology. We formulated inks by combining pea fractions with water and employing a water-holding-capacity based hydration method. Rheology is characterized by steady shear rate and oscillatory strain amplitude sweeps. Strain sweep curves infer that the deformation response of all inks follows a similar trend, and samples sharing the same macronutrient formulation are mapped to a master curve after scaling with the elastic plateau modulus. Samples sharing the same macronutrient formulation mapped to a master curve after scaling with the elastic modulus. Shear rate testing showed that the inks were shear thinning yield stress materials. Shear rate sweeps also collapsed on a master curve scaled by the yield stress and critical shear rate on the y and x axes. The yield stress and the plateau modulus appeared to be controlled by the water content, while the shear and strain thinning exponents were independent of the formulations, inferring that the rheology is scaled by the water content while preserving the shear thinning response. Observing the independence of the rheological properties from the nutrient composition and scalability of the rheology by the water content provided a step forward in developing formulations with various nutrient content at desired ow properties, which promises personalized nutrition. Furthermore, the study shows the applicability of various rheological techniques, which are expected to contribute to the literature on the rheology of granular pastes.

Dynamic in situ microstructure evaluation of cheese melting: Understanding structure-rheological relationships under controlled temperature sweeps

This study assessed the changes in processed and natural cheese during heating from 5 to 95 °C, at 2 °C per min, using confocal laser scanning microscopy (CLSM), Raman micro-spectroscopy and rheological analysis. The CLSM images showed that the cheese samples varied in fat droplet size and distribution. CLSM micrographs of processed cheese with lower fat content (<10%) showed no substantial structural changes during heating, which were consistent with the absence of cross-over in temperature rheology sweep curves. Cheese containing starch showed uniformly distributed fat and cohesive protein network, leading to reduced cheese flow. At temperatures > 70 °C, cheeses with a fat content ≥ 25% showed greater coalescence of fat globules, which finally merged into large fat pools. The results of this study demonstrate the potential of dynamic in situ CLSM and rheological analysis for evaluating the changes in cheese matrices during heating. The Raman spectral region corresponding to C-H stretching vibrations (2800–3000 cm-1) could be used to track fat melting in cheese samples with minimum 10% fat.

Passive aeroelastic study of large and flexible wind turbine blades for load reduction

In this paper, passive aeroelastic coupling of wind turbine blades for load reduction is realized by introducing bending-twist coupling (BTC) and geometric sweep coupling (GSC). The BTC is implemented by composite fiber off-axis of the blade spar cap, and the GSC is achieved by defining sweep curves of the blade reference axis. To investigate the passive coupling effect and load reduction of the large and flexible blades, the IEA 15 MW blades are considered. BTC are introduced into the three-dimensional finite element (FE) models and the residual stiffness coefficient is obtained. Meanwhile, geometrically exact beam theory (GEBT) is used to build the flexible blade. Both BTC and GSC are introduced into the beam model, and the effect elastic deformation on blade load is also considered. Multi-objective optimization (MOO) process of rotating blades for load reduction is proposed under steady-state rated conditions. The results show that the highest coupling efficiency can be obtained when the fiber off-axis angle is between 12° and 15°. The BTC of the blade can reduce the load of blade root with a small fiber off-axis angle. Meanwhile, the GSC can further reduce the axis torque. Compared with the initial design of IEA 15 MW steady-state rotating blade, the maximum thrust, flapwise moment and axis torque of the blade can be reduced by 8.8 %, 13.4 % and 22.9 % respectively.

Extraction of photoluminescence with Pearson correlation coefficient from images of field-installed photovoltaic modules

Photoluminescence imaging of field-installed photovoltaic modules has the potential to be a high throughput on-site inspection technique. A contribution to this development is a noninvasive photoluminescence imaging method that has been proposed recently. It is based on acquiring images during a progressing current–voltage curve sweep, resulting in a detection of a continuously changing photoluminescence signal. From this follows the necessity to employ an alternative algorithm based on the Pearson correlation coefficient, which will contribute to efficient, unsupervised image processing and, thus, easier (in real-time) implementation. The new algorithm separates photoluminescence from the reflected sunlight, similar to the conventional subtraction algorithm. However, it is robust to varying solar irradiance and can process the photoluminescence signal emitted from multiple asynchronized strings. We predict that it will enable unsupervised real-time surveillance and detection of functional anomalies at a low computational cost. It is also more sensitive at segmenting ground-reflected photoluminescence.

Role of gelation temperature in rheological behavior and microstructure of high elastic starch-based emulsion-filled gel

Gelation temperature is a critical factor for starch-based emulsion-filled gel structure design. Its role in the rheological properties under small and large amplitude oscillatory shear and microstructure containing interfacial construction and matrix network of emulsion-filled gel with starch as emulsifier and polymeric gel matrix was investigated for the first time. The gel was found to maintain high elasticity over entire gelation temperature range of 55–90 °C, confirmed by frequency sweep, creep-recovery, and Lissajous curves analysis. Intact starch granules and/or starch molecules in emulsion-filled gel systems varied with temperature, which regulated interfacial structure and gel matrix. The interfacial network was visualized by cryo-scanning electron microscopy in this study. Starch molecules were preferentially adsorbed at the interface over granules. And at 55 °C, the starch molecules leached out from granules to form an active-filled emulsion gel network by connecting the granules and/or oil droplets. Increasing temperature to 60 °C enhanced gel strength related to swollen granules filling volume, while strength decreased at higher temperatures by granule disintegration. Differently, the resistance of emulsion-filled gel to large deformation causing structural destruction increased monotonically with temperature, accompanied by a significant increase in their critical strain from 2.01% to 80.32%, suggesting more stretchable structure. This was supported by a strongly interacted emulsion-filled gel system with enhanced oil-starch interfacial interaction and denser molecular matrix network. And structural variations were further correlated to their nonlinear behavior by Higher harmonics, Chebyshev coefficient, and Lissajous curves analysis. This work could provide guidance for starch emulsion gel structure design and/or practical application in food industry.

The Measurement and SPICE Modelling of Schottky Barrier Diodes Appropriate for Use as Bypass Diodes within Photovoltaic Modules

The modelling of surges within PV (photovoltaic) installations has been the subject of much research in recent years. However, accurate simulations cannot be performed unless each and every component within a PV installation is modelled in sufficient detail. The bypass diodes within a PV module are frequently omitted from such simulations. When included, they are often represented by oversimplified models. This article addresses this need by presenting SPICE (Simulation Program with Integrated Circuit Emphasis) models for three Schottky diodes, chosen due to their suitability for use as bypass diodes. These models are the combination of DC (direct current) large-signal and AC (alternating current) small-signal sub-models, which are integrated such that the resulting full circuital models allow for accurate simulations involving large-signal transient stimuli. Two types of experimental setups, one incorporating a DC current–voltage curve sweep, and the other involving VNA-based (vector network analyser) AC small-signal impedance measurements, allow for the acquisition of the necessary model parameters at multiple operating points. The AC small-signal measurements cover a wide bandwidth of 100 Hz to 50 MHz. Multiple configurations of the measurement setups are employed in order to achieve the required dynamic range and sensitivity.

Formulation of zwitter-ionic terpolymeric hydrogels and their comprehensive rheological investigation

With the rapid enhancement in pharmaceutics, cosmetics, medical applications, and water contamination, the demand of hydrogels with varying properties is increasing day by day. Hydrogels with keen properties like pH sensitive, thermosensitive, biocompatibility, visco-elasticity, mechanical rigidity, and resistive to exterior stress are of great interest. In order to attain such properties for above mentioned applications, a zwitter ionic hydrogel was synthesized having flexible nature, pH sensitive and is tested using rheometer. Rheological properties are elucidated using frequency sweep and flow curve analysis. The fluidity index lower than unity indicates the non-Newtonian shear thinning behavior. The lower value of shear thinning makes it a feasible candidate to be used in paints and cosmetics industries like nail polish, lotions etc. Values for consistency index increased with rising temperature and increasing amount of AMPS. The increase in consistency coefficient and yield stress with increasing temperature from 25 to 35 ̊C indicates the strengthing of hydrogels which will facilitates jellification of drug delivery system on skin. Modified Bingham model was found the best fit to our rheological data. The thermodynamic data obtained revealed higher activation energy for ZHG-02 with greater concentration of AMPS than ZHG-01 with lower amount of AMPS.

Morphogenesis – “The Riddles of Form” in Twenty-First Century Science

Morphogenesis – “The Riddles of Form” in Twenty-First Century Science

Rheo-viscoelastic behavior and viscosity prediction of calcium sulphoaluminate modified Portland cement pastes

In this study, the rheo-viscoelastic behaviors of calcium sulphoaluminate (CSA) modified Portland cement (PC) pastes were investigated. The shear stress, apparent viscosity, frequency sweep and time sweep curves of composite pastes with different PC and CSA volume fractions were analyzed, and the minimum apparent viscosity (ηmin) of PC-CSA pastes were predicted. Results show that with the increase of PC and CSA volume fractions, ηmin, critical strain and flow strain of pastes increase at both 5 min and 60 min resting time, and the phase angle varies under different time spots. The accuracy of viscosity prediction models for 5 min and 60 min are both relatively high. Meanwhile, the reason why the prediction accuracy of 5 min is higher than 60 min is that with the prolongation of resting time, the relationships between particle volume fractions and rheological properties are affected by early microstructure formed by flocs and hydration products, thus affecting their original functional relationship at 5 min.

Brownian dynamics simulation on orthogonal superposition rheology: Time–shear rate superposition of colloidal gel

The dynamics of model colloidal gels under a steady shear flow is studied by means of a Brownian dynamics (BD) simulation while applying orthogonal superposition rheometry, which superimposes a small amplitude oscillatory flow orthogonal to the main flow direction. Orthogonal dynamic frequency sweep (ODFS) curves are obtained at various magnitudes of the main flow, which shows shear thinning behavior of the colloidal gel. The viscoelastic spectra of the ODFS can be superimposed onto a master curve by the horizontal shift factor, which is equivalent to particle viscosity. That is, the shear rate controls a single master clock for all viscoelastic spectra of the ODFS in the form of a time–shear rate superposition, which bears an analogy with the time–temperature superposition of polymeric systems. In the low-frequency region of the master curve, both orthogonal moduli are well superimposed onto a single master curve, whereas the loss modulus deviates slightly from the master curve in the high-frequency region, which coincides with the experimental findings. We observe spatial and time-varying structural properties in both low- and high-frequency regions on the ODFS curves by decomposing the pair distribution function. It is verified that each flow condition shifted onto the same stress level on the master curve shows identical spatial orthogonal moduli at all radial distances despite the differences in the aggregate size and average particle connectivity.

Double stabilization mechanism of O/W Pickering emulsions using cationic nanofibrillated cellulose

HypothesisHydrophobic oleic acid/water interfaces are negatively charged. Hence, the use of cationic nanocelluloses as stabilizers of Pickering emulsions could improve the colloidal stability due to the electrostatic complexation at the oil-water interface. ExperimentsTwo cationic nanofibrillated cellulose (cNFCs) with two degrees of substitution were prepared and used as stabilizers of Pickering emulsions. The adsorption of cNFCs at the oil: water interface was evaluated by interfacial tension, atomic force microscopy, and centrifugation measurements. LUMiSizer and optical microscopy techniques were used to analyze the colloidal stability and oil droplets morphology, respectively. Besides, the rheological behavior of the continuous aqueous phase was determined through flow and stress sweep curves. Finally, the dispersion of cNFCs in a diluted emulsion was visualized by cryogenic transmission electron microscopy (cryo-TEM). FindingsCationic NFCs were more efficient in partitioning to the oil:water interface compared to their anionic analogous, oCNF. The electrostatic attraction between the positively charged trimethylammonium groups and the negatively charged deprotonated oleic acid reduced the interfacial tension and improved the colloidal stability of O/W Pickering emulsions. cNFCs dispersed in the aqueous phase were found to increase the viscosity, decelerating the oil drops coalescence. Therefore, the stabilization of cNFCs Pickering emulsions had a synergistic effect from the electrostatic complexation at the liquid-liquid interface and network formation in the aqueous phase, as visualized by cryo-TEM.

Internet of Things (IoT) based outdoor performance characterisation of solar photovoltaic module

Outdoor performance characterisation of the Solar Photovoltaic (SPV) module is essential to while designing and commissioning a new SPV power plant. The health of SPV plant is monitored using a conventional method which underutilises the workforce and resources used for Operation and Maintenance (O&amp;M) of the SPV power plant. Outdoor performance characterisation of SPV module using reliable, compact, portable, and economical Current-Voltage (I-V) curve tracer having IoT capability and auto sweep capability is presented in this paper. The capacitive load method is used for I-V curve sweep, and the result is compared with the resistive load method. In this paper, the advantages of using a capacitive load method over resistive load method are observed and experimentally validated. The ease of using IoT feature makes this proposed I-V Curve Tracer (IVCT) device more reliable to trace Current-Voltage (I-V) curve and Power-Voltage (P-V) curve for outdoor performance characterisation of SPV module.

Normally-Off Hydrogen-Terminated Diamond Field Effect Transistor With Ferroelectric HfZrOx/Al2O3Gate Dielectrics

A hydrogen-terminated diamond (H-diamond) Field effect transistor (FET) with a ferroelectric HfZrOx/Al2O3 stacked gate dielectric was demonstrated for the first time. The HfZrOx(16 nm)/Al2O3(4 nm) gate dielectric was grown by atomic layer deposition (ALD) at 300 °C. The bowknot-like capacitance-voltage hysteresis and the transfer characteristic curves in clockwise hysteresis loop directly illustrated the ferroelectricity of the device. A memory window as wide as 7.3-9.2 V, the maximum on/off ratio of 109 and the subthreshold slope (SS) of about 58 mV/decade was measured for the gate voltage sweeping between 10.0 to −10.0 V in the linear region. A completely normally-off behavior was observed in the saturation region because both threshold voltages ( $\text{V}_{\mathrm {th}}$ ’s) for forward and reverse sweeping transfer characteristic curves are negative at a drain voltage of −15 V. It is ascribed to that the polarization state of the HfZrOx dielectric along the channel changes from uniform in the linear region to strongly nonuniform in the saturation region. These results hint that HfZrOx/Al2O3/H-diamond FETs provide new possibility of diamond normally-off FETs, negative capacitance FETs and non-volatile memory of high density integration.

Effect of H2 on interface traps in the LPNP transistors caused by 3 MeV proton irradiations

In this paper, the effects of 3 MeV proton irradiations on gate controlled lateral PNP (GLPNP) transistors are investigated with and without molecular hydrogen (H2) soaking. The electrical parameters are measured in-situ during irradiation. Radiation defects indicated by 3 MeV protons are measured by deep level transient spectroscopy (DLTS). At a given the irradiation fluence, the degradation for the H2-soaked transistors is much larger than that for the non-soaked transistors. Excess base current (ΔIB) for the H2-soaked transistors is bigger than that for the non-soaked transistors at a given emitter-base voltage and the same irradiation fluence. According to the gate sweep (GS) curve, it can be calculated that the number of the interface traps of the H2-soaked transistors is significantly larger than that for the non-soaked transistors under the same fluence, as demonstrated by DLTS analyses. 3 MeV protons could mainly produce the ionization damage in the GLPNP transistors, displacement damage can be almost negligible. The results for the 70 keV electron irradiations further confirm that 3 MeV protons could mainly produce ionization damage in the GLPNP transistors and hydrogen can aggravate the formation of interface traps in GLPNP transistors.

Enhancement of oxygen reduction on a newly fabricated cathode and its application in the electro-Fenton process

High catalytic activity, energy-saving cathodes are desirable for improving the efficiency of the electro-Fenton system. Herein, carbon felt (CF) modified with graphene oxide (GO) and anthraquinone sulfonate (AQS) as a cathode was fabricated. The CF/GO/AQS cathode with excellent catalytic performance for oxygen reduction was further applied in the electro-Fenton process. Surface morphology and structural characteristics of CF/GO/AQS cathode were characterized by scanning electron microscopy (SEM), X-ray spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. Rhodamine B (RhB) was applied as the target pollutant, and the decolorization rate could reach 95% within 1 h using the CF/GO/AQS cathode, which was 2.3 times higher than that of the unmodified cathode. It was attributed to the prominent capacity to accelerate oxygen reduction reaction (ORR) of CF/GO/AQS cathode. The response current of CF/GO/AQS reached −2.48 mA cm−2, which was about six times higher than that of the bare CF cathode. Electron transfer number determined by linear sweep curves on a rotating disk electrode was calculated to be 1.9–2.2, which indicated the catalytic reduction of molecular oxygen by CF/GO/AQS cathode was dominated by a two-electron reaction pathway. Quinones can catalyze the reduction of molecular oxygen to superoxide radicals. Then the formed superoxide radicals combine with protons to produce hydrogen peroxide (H2O2), which provides a new way of H2O2 generation applied in the electro-Fenton system. The TOC removal rate arrived at 89.9%, and corresponding energy consumption was 4.23 kWh kg−1. The catalytic performance of the CF/GO/AQS cathode kept almost stable after six cycles of a repeated experiment. This new CF/GO/AQS cathode can be a promising material applied in the electro-Fenton process for organic pollutant removal.

Rheological Investigation of GO Doped p(APTMACl) Composite Hydrogel

Abstract The aim of the present work is an approach towards the exploration of comprehension of rheological work on polymer composites synthesized by ex-situ dispersion of graphene oxide (GO) in poly(3-acrylamidopropyl trimethyl ammonium chloride (APTMACl) cationic hydrogel template. FTIR was carried out for confirmation of polymer synthesis and existence of GO in hydrogel network. The rheological investigation via frequency sweep curve (shear measurement) and oscillatory sweep (dynamic mechanical analysis) at different temperature 20, 25, 30, 35, 40 and 45 °C was performed. The storage (G′) and loss (G′′) moduli as a function of angular frequency, yield stress, tangent loss, damping factor and retention property were also studied to confirm the visco-elastomeric nature of the GO@p(APTMACl) composite and their semi solid response at different range of temperature. Various rheological models like Bingham model, modified Bingham model and Ostwald’s power law were applied. The temperature dependency was further tested via Arrhenius-Frenkel-Eyring equation. The sample showed best fitting in the modified Bingham model, which justified the pseudo plastic semi solid behavior of GO@p(APTMACl) composite within the linear visco-elastic region (LVER). All the properties from rheological study show best mechanical property and make the composite hydrogel good for drug delivery and for other environmental applications.

Effect of protons located at different region in SiO2 layer on GLPNP transistors degradation

Based on 100-keV, 130-keV and 170-keV proton irradiations, the contribution of ionization damage to the electrical property degradation of gate controlled lateral PNP (GLPNP) transistors is investigated. The key electrical parameters are measured in-situ during irradiations. The radiation-induced defects are characterized by deep level transient spectroscopy (DLTS). Experimental results show that the same ionization dose of various energy protons caused different degradation of current gain in GLPNP transistors. The current gain of the irradiated transistors by 170-keV protons degrades obviously, while that of the irradiated transistors by 100-keV protons does not almost change. As the ionization dose increases, the excess base currents of the irradiated transistors by 170-keV and 130-keV protons increase. The ideality factor of the irradiated transistor by 170-keV protons changes, while that of the transistor irradiated by 130-keV protons does not change. The gate sweep (GS) curves show that the main ionization defects induced by different protons are the interface traps. Compared with the irradiated transistors by 100-keV and 130-keV protons, the irradiated transistors by 170-keV protons has a high gate sweep peak at the same dose indicating that the 170-keV protons induced more interface traps. Therefore, the protons located at different region in SiO2 of GLPNP transistors can induce different degree of degradation, and the location of the proton is closer to the Si/SiO2 interface, the number of the radiation-induced interface traps is the more.

Enhanced Operation Characteristics for Charge Trapping Memory with Al2O3/HfO2/Al2O3 High-κ Dielectrics and Sige Substrate

Recent technology advances have moved nonvolatile memory (NVM) to the forefront as key enablers of computing-in-memory for AI chips and nonvolatile logics for IoT devices. Among the family of NVMs, charge trapping memory (CTM) devices has been widely used to realize low power consumption and high speed. In conventional SONOS-type CTM, it becomes hard to improve the program and erase (P/E) speed by optimizing tunneling oxide thickness while still maintaining the retention properties [1]. To confront the challenges faced by SONOS memory, various high-κ dielectrics (Ta2O5, ZrO2, Y2O3, HfO2, etc.) with reduced equivalent oxide thickness (EOT) and improved charge-trapping density are proposed to achieve better memory performance [2-3]. Apart from the adoption of high-κ dielectrics for CTM, the adoption of channel material can also improve memory performance. Recently, some efforts on the utilization of SiGe channel with high electron/hole injection rate have been reported to improve P/E efficiency [4-5]. Electron/hole injection increased because SiGe has a smaller bandgap than silicon. As the electron/hole injection located at tunneling oxide/SiGe channel increases, the number of electrons tunneling through the tunneling oxide is increased and the P/E speed is improved. In this paper, we proposed a novel memory device with high-κ Al2O3/HfO2/Al2O3 nanolaminate, SiGe channel and high work function tungsten metal gate. Finally, a novel charge trapping memory with the structure of [W/TiN]/Al2O3/HfO2/Al2O3/SiGe (named as MAHASG in short) is obtained. MAHASG memory devices with SiGe buried channel, as shown in Fig. 1, were fabricated on p-type Si wafer. Prior to SiGe epitaxial growth, the surface oxide was removed by using a dilute HF 1% solution. Then a 20 nm-thick SiGe epi-layer with 30% Ge content was deposited using reduced pressure chemical vapor deposition (RPCVD). After SiGe epitaxial growth, a 3 nm Al2O3 tunneling layer was deposited by atomic layer deposition (ALD) at a substrate temperature of 300℃. Subsequently, the 7 nm HfO2 film was grown by ALD as the charge trapping layer. Then, another 6-nm thick Al2O3 layer was deposited by ALD in situ as the blocking layer. After that high-κ dielectrics deposition, a post deposition anneal was performed for 15 s at the temperature of 450 °C in N2 atmosphere to improve the material quality of the high-κ dielectrics. Afterwards, TiN/W was deposited as the control gate by ALD and patterned by dry etch, followed by sputtering aluminum as the backside contact. Finally, a metallization process by using forming gas (5% H2, 95% N2) was applied for 30 min and at 400℃. Control samples without HfO2 layer were also fabricated using identical procedure. The resulting structure is shown in Fig 1. It should be noted that the whole process is simple and fully compatible with conventional CMOS technology. The memory characteristics for the MAHASG memory devices were investigated by a Keithley 4200 semiconductor characterization system. In order to study the charge trapping characteristics, bi-directional capacitance-voltage (C-V) curves were obtained by applying different sweeping gate voltages ranging from ±3 V to ±10 V at a frequency of 800 KHz, as shown in Fig. 2. A counterclockwise hysteresis was obtained during voltage sweep from inversion region to accumulation region and then back to inversion region. The memory window is defined as the flat-band voltage shift (ΔVFB) between the forward and backward sweep curves. There is no obvious memory window in the voltage sweep of ±3 V, indicating that charge trapping and de-trapping hardly take place in this voltage sweep range. When the voltage sweep range increases to ±6 V, the memory window is obvious. In a voltage sweep range of ±10 V, a large memory window of about 4 V can be obtained, as indicated in Fig 3. The energy band diagram of the MAHASG memory device is shown in Fig 4. The barrier height for electron injection from the SiGe channel to the HfO2 layer is about 2.74 eV, which is slightly smaller than that of the normal Si-SiO2 system (3.25 eV). This means that a higher charge tunneling probability and program efficiency occurred in this memory structure. In conclusion, this study provides a promising route of future nano-scaled flash memory operation, utilizing high-mobility channel and high-κ materials.

One-Pot Synthesis and Rheological Study of Cationic Poly (3-acrylamidopropyltrimethyl ammoniumchloride) P(APTMACl) Polymer Hydrogels

Abstract The main objective of this research work is to explore the complete and extensive rheological studies of cationic poly (3-acrylamidopropyl trimethyl ammonium chloride) P(APTMACl) hydrogel, prepared by free radical polymerization method at room temperature. Hydrogel was characterized by various techniques such as SEM, FTIR and TGA, whereas rheological properties of synthesized hydrogel were obtained using frequency sweep and frequency curve analysis in different temperature range. Storage modulus (G′) and loss modulus (G′′) were investigated as a function of angular frequencies and shear stress at various temperatures. Rheological models like Bingham plastic model, modified Bingham and Ostwald power law were applied to understand the rheological performance of the gels. Flow curves obtained at different temperatures indicate that P(APTMACl) hydrogel shows a non-Newtonian pseudo plastic behavior. All results concluded that rheology is a powerful tool to study the complete visco-elastic behavior of polymer hydrogel for multiple applications.