Full-Space Scanning Leaky Wave Antennas With High Scanning Rate and Enhanced Efficiency via Periodic High-Q Resonant Network Loading

Aims: To evaluate the relationship between daily sensor scan rates and changes in HbA1c and hypoglycemia in children. Methods: We enrolled 145 paediatric T1D patients into a prospective, interventional study of the impact of the FreeStyle Libre 1 system on measures of glycemic control. Results: HbA1c was higher at lower scan rates, and decreased as the scan rate increased to 15–20 scans, after which it rose at higher scan rates. An analysis of the change in hypoglycemia, based on the number of daily sensor scans, showed there was a significant correlation between daily scan rates and hypoglycemia. Subjects with higher daily scan rates reduced all levels of hypoglycaemia. Conclusions: HbA1c is higher at lower scan rates, and decreases as scan rate increases. Reductions in hypoglycemia were evident in subjects with higher daily scan rates.

The drastic distortion of potentiodynamic polarization curves measured at high potential scan rates prevents the extraction of accurate kinetic parameters. By measuring potentiodynamic polarization curves of AA7075 at scan rates ranging from 0.167 mV/s to 100 mV/s, in an acidic solution of 0.62 M NaH2PO4 and a near-neutral 3.5 wt% NaCl solution, changes in potentiodynamic polarization curves are observed not only at different scan rates and electrolytes but also between replicated experiments. Contrary to what was reported in previous studies, the disturbance of charging current associated with high scan rates does not satisfactorily explain the potentiodynamic polarization shape. Instead, the high field model that incorporates the kinetics of anodic oxide growth successfully captures the features of experimental potentiodynamic polarization curves. Compared to Tafel’s theory, the high field model explains remarkably both the changing kinetics with scan rates, electrolytes, and the variance between the measurement performed at different sites. Figure 1

The drastic distortion of potentiodynamic polarization curves measured at high potential scan rates prevents the extraction of accurate kinetic parameters. In this work, we start by measuring potentiodynamic polarization curves of AA7075 at scan rates ranging from 0.167 mV·s−1 to 100 mV·s−1, in an acidic 0.62 M NaH2PO4 solution and a near-neutral 3.5 wt% NaCl solution. Changes in potentiodynamic polarization curves are observed not only at different scan rates and electrolytes but also between replicated experiments. Contrary to what was reported in previous studies, the disturbance of charging current associated with high scan rates does not satisfactorily explain the potentiodynamic polarization shape. Instead, the high field model that incorporates the kinetics of anodic oxide growth successfully captures the features of experimental potentiodynamic polarization curves. Compared to Tafel’s theory, the high field model explains remarkably the changing kinetics with scan rates, electrolytes, and the variance between measurements performed at different sites.

The scanning rate of a composite right/left-handed (CRLH) leaky-wave antenna (LWA) is usually determined by the dispersive behavior of the corresponding CRLH unit cell. In this letter, a novel CRLH unit cell with high dispersive behavior is proposed and investigated. The unit cell is formed by four stubs embedded in a rectangular ring patch, which is grounded with several metal vias. The right-handed characteristic is enhanced by the ring patch, while the left-handed characteristic is reduced by the vias and the gaps between the patch and the stubs. Then, the unit cell is applied to design an LWA with high scanning rate. The measured result shows that the seamless scanning angle of the antenna prototype is 130° (−65° to +65°) within a frequency range from 9.3 to 9.93 GHz (i.e., 6.6% for fractional bandwidth). Therefore, the proposed LWA antenna is with a high scanning rate up to 19.7°/%BW.

Experimentation and numerical modeling of cyclic voltammetry for electrochemical micro-sized sensors under the influence of electrolyte flow

Scanning electrochemical cell microscopy (SECCM) is progressively employed for investigating corrosion behaviors at localized sites on metal surfaces. Normally, hundreds of potentiodynamic polarization (PDP) measurements are conducted on the sample using a high potential scan rate to reduce the experimental duration. However, polarization curves obtained under such conditions would yield inaccurate Tafel kinetics. In this research, we performed PDP measurements on Al sample at various scan rates using SECCM and obtained reproducible results. The experimental polarization curves were successfully simulated by a high field model that accounted for the cathodic contribution from oxygen reduction reaction and the anodic contribution from Al oxide film growth. By utilizing this model, we were able to extract the true corrosion kinetic properties from the high scan rate polarization curves, which has not been reported previously. This study represents a significant contribution towards enhancing SECCM-based micro-polarization as a robust quantitative technique for corrosion study.

Soft robots can adapt to dynamic environments without prior knowledge of their properties. Plants inspire mechanisms for counterbalancing dynamic loads by locally modulating compliance through anisotropic humidity-responsive materials and structures. In addition to well-known passive bilayers, plants may also actively control swelling. The combination of robust hygroscopic material-level response and simple electrical control makes active swelling particularly attractive for technological implementation. However, dynamic swelling demands the development and optimisation of congruent pumping solutions. This work suggests electrohydrodynamic pumping, enabled by highly reversible ion immobilisation at capacitive electrodes, as a particularly suitable low-pressure, high-area liquid displacement solution for active swelling. Local pore fill ratio (PFR) modulation is used as a measure for dynamic liquid displacement and swelling. A method for highly localised (10 μm membrane thickness) assessment of the dynamic variation of PFR in a 400 μm laminate undergoing cross-plane electrokinetic liquid displacement is developed. Two modes for transient PFR modulation were identified: electrokinetic ion transfer and diffusive solvent redistribution, pronounced at high and low voltage scan rates, respectively. The strategic combination of these modes enables various compliance-modulation scenarios. The system contains (within a cycle) a constant amount of liquid in an open network of liquid-filled pores. 30%–75% PFR yielded the highest dynamic PFR modulation: a high amount of empty pores is beneficial, yet a too-low PFR compromises the continuous liquid pathway necessary for electrokinetic pumping. The dynamic nature of internal liquid rearrangement was characterised by relatively fast electrokinetics-driven fluxes (6.3% PFR change in 80 s), followed by a slow equilibration of concentration and PFR. At high scan rates, PFR decreased at positive polarisation, while both positive and negative polarity yielded a similar decrease at low scan rates (5 mV s−1). Localised control over the swelling gradient enables the design of systems that morphologically adapt to complex dynamic loading conditions.

Scanning electrochemical cell microscopy is becoming the tool of choice for the investigation of localized metal corrosion. Typically, potentiodynamic polarization measurements in scanning electrochemical cell microscopy are performed at high potential scan rates. However, Tafel extrapolation applied to high-scan-rate potentiodynamic polarization curves would yield inaccurate corrosion kinetics due to the interference of double-layer charging current or mass transport of species in the metal oxide. Instead, the high field model was used to simulate the potentiodynamic polarization curves of pure aluminum at 25, 50, 100, and 200 mV/s in neutral and acidic phosphate solutions, thus enabling quantitative analysis of local corrosion kinetics by fitting the potentiodynamic polarization curve.

Our aim was to assess differences in glycemic metrics according to diabetes type and therapy in Japan. An optional survey was conducted for users of FreeStyle LibreTM readers in Japan (Jun2020 - Oct2020). Survey responses were linked to glucose data from Jan2017 - Oct2020. Four groups (adults) were used: type 1 diabetes (T1), type 2 on intensive insulin (T2 MDI), T2 on basal or pre-mixed insulin (T2 non-MDI), and T2 not on insulin (T2 non-insulin). A total of 2,434 users in Japan were analyzed: 1,237 T1, 429 T2 MDI, 256 T2 non-MDI, and 512 T2 non-insulin. Glucose control for T2 MDI and T2 non-MDI groups was similar. Mean avg glucose for T1 was similar to T2 insulin users, but TIR was lower and TB70 was higher for T1. The non-insulin group had high engagement (mean 21 scans/day), but tested BG less than once/day prior to the sensor. These patients also largely pay for the device without reimbursement and have more recent diabetes diagnoses than other groups. These data show the variety of users of the FreeStyle Libre system in Japan. The non-insulin group's engagement through high average scan rates despite lack of consistent BG testing before using the sensor demonstrates that patients find value in easier monitoring. High scan rates in all groups indicate that scanning is not a barrier to glucose monitoring. The data selects those users who responded to the optional survey but is comparable to the overall glucose control of all users in Japan.View largeDownload slideView largeDownload slide DisclosureW. Ogawa: Advisory Panel; Self; Abbott Diabetes, Novo Nordisk Pharma Ltd., Research Support; Self; Eli Lilly Japan K. K., Nippon Boehringer Ingelheim Co. Ltd., Takeda Pharmaceutical Co., Speaker's Bureau; Self; Dainippon Sumitomo Pharm, Kowa Company, Ltd., MSD K. K., Novartis Pharma K. K., Ono Pharmaceutical Co., Ltd. T. Urakami: None. T. Kadowaki: Other Relationship; Self; Asahi Mutual Life Insurance Company, MSD Corporation, Nippon Boehringer Ingelheim Co. Ltd., Novo Nordisk Pharma Ltd., Takeda Pharmaceutical Company Limited, Research Support; Self; Daiichi Sankyo Company, Limited, Eli Lilly Japan K. K., Kyowa Kirin Co., Ltd., Mitsubishi Tanabe Pharma Corporation, MSD Corporation, Novo Nordisk Pharma Ltd., Ono Pharmaceutical Co., Ltd., Sanofi K. K., Sumitomo Dainippon Pharma Co., Ltd., Takeda Pharmaceutical Co., Speaker's Bureau; Self; Astellas Pharma Inc., AstraZeneca, Daiichi Sankyo Company, Limited, Eli Lilly Japan K. K., Kowa Company, Ltd., Kyowa Kirin Co., Ltd., Mitsubishi Tanabe Pharma Corporation, MSD Corporation, Nippon Boehringer Ingelheim Co. Ltd., Novo Nordisk Pharma Ltd., Ono Pharmaceutical Co., Ltd., Sanofi K. K., Sanwa Kagaku Kenkyusho, Sumitomo Dainippon Pharma Co., Ltd., Taisho Pharmaceutical Co., Ltd., Taisho Pharmaceutical Co., Ltd. K. Kao: Employee; Self; Abbott Diabetes. L. Brandner: Employee; Self; Abbott Diabetes. K. Shimizu: Employee; Self; Abbott Japan Co., Ltd. T. Dunn: Employee; Self; Abbott Diabetes.

The electrochemical synthesis of poly(aniline- co- o-anisidine) on copper and their corrosion performances

A seamless scanning dual-beam leaky-wave antenna (LWA) suited for multiobject detecting and tracking without blindness exhibits potential applications in wireless communication and radar systems. The beam scanning rate is a key indicator to measure the scanning performance of LWA. However, the high scanning rate dual-beam LWA with continuous scanning is seldom considered in the published literature. Defined first as the sum of the scanning rate of each beam in this communication, a novel asymmetrical dual-beam LWA with a high scanning rate of 12.9 is then proposed based on the combination of a half-mode substrate-integrated waveguide (HMSIW)-surface plasmon polaritons (SPPs) structure and a sinusoidally modulated reactance superposing surface (SMRSS) technique. The hi gh scanning rate is attributed to the dispersion enhancement of the slotted HMSIW-SPP unit, while periodic modulation superposed and uniform slots etched on the top and bottom layers, respectively, contribute to the asymmetrical dual-beam continuous scanning. As an example, an X-band asymmetrical dual-beam LWA is implemented and measured. Over the band of 8.65–9.5 GHz [9.3% fractional bandwidth (BW)], the proposed dual-beam LWA achieves a seamless beam scanning from −65° to −2° and from −6° to +51°, respectively.

Graphene-based nanomaterials are very promising for wearable and flexible electronics because of their unique electrical and mechanical properties. However, their difficult chemical synthesis has limited wide-spread commercial adoption. In particular, energy storage devices such as micro-supercapacitors require a porous morphology for large specific surface area and patterning such as interdigitated designs, which traditionally requires multiple complex fabrication steps. Laser-induced graphene (LIG) is a recently developed method that solves this problem by simultaneously generating and patterning porous graphene electrodes. Laser irradiation of a polyimide (PI) substrate selectively transforms the PI into graphene. This method shows promise to fabricate miniaturized energy storage devices at low cost and on a flexible substrate. However, the capacitance of LIG micro-supercapacitors needs to be improved by developing novel charge storage mechanisms compatible with LIG electrodes. Typically, energy storage mechanisms are classified as either electrochemical double-layer capacitance (EDLC) or pseudocapacitance. EDLC is enhanced by facile adsorption of electrolyte ions on the electrode material. Therefore, light weight carbon-based materials such as activated carbon, carbon nanotubes, graphene and their different combinations are suitable for EDLC but ultimately their performance is limited by their specific surface area. Pseudocapacitance allows further charge to be stored beyond the limitations imposed by the electrode’s surface area utilizing redox reactions of the electrode material with the electrolyte ions. There has been extensive interest in enhancing pseudocapacitance using various redox reactions between electrode materials such as transition metal oxides, conducting polymers and electrolyte ions. Carbon-based large-scale supercapacitors have been reported with improved performance by adding redox species, which can undergo redox reactions with the carbon-based electrodes, to the electrolyte. Reports on micro-supercapacitors using redox electrolytes have been limited to electrodes fabricated by complex multi-step fabrication processes. Here, we report graphene micro-supercapacitors fabricated by one-step laser scribing with enhanced capacitance utilizing a redox electrolyte. Hydroquinone (HQ) is a promising candidate as a redox additive in the electrolyte owing to its double charge transfer mechanism i.e. loss of 2H+ and 2e- during the charging process, which results in benzoquinone (BQ). Similarly, BQ is reduced to HQ by gaining 2H+ and 2e- during discharging. HQ (0.5 mol/L) was added to the aqueous H2SO4 (1 mol/L) electrolyte, which was deposited onto interdigitated LIG electrodes. The laser parameters were optimized to achieve LIG with a fibrous morphology. Fig.1a shows a scanning electron microscope (SEM) image of the cross-section of the fibrous LIG on PI. The addition of HQ as a redox-active additive enhanced specific capacitance approximately 5 times compared to devices without the HQ additive. The unmodified H2SO4 electrolyte exhibited an areal capacitance of 0.8 mF/cm2. Addition of HQ raised the total capacitance to 3.9 mF/cm2 as calculated from the area under the cyclic voltammetry curve in Fig.1b. Cyclic voltammetry of the device with HQ electrolyte showed very strong peaks due to oxidation and reduction of HQ and BQ as shown in Fig. 1b. A typical cyclic voltammetry graph with rectangular shape due to EDLC was observed in H2SO4 at 10 mV/s scan rate. It remained stable even at a high scan rate of 1000 mV/s as shown in Fig.1c-d. These results demonstrate the conductive nature of the engraved graphene and facile adsorption of the H+ ions. The device was further tested at higher scan rates after the introduction of HQ (10-1000 mV/s as shown in Fig.1e-f. The redox peaks were found very stable at higher scan rates and their peak values move towards extreme potentials at higher scan rates. To further investigate the motion of electrolyte ions within the pores of the fibrous graphene, electrochemical impedance spectroscopy (EIS) was performed with and without HQ in H2SO4 (see Fig.1g-j). A semi circle at low frequencies was observed (see Fig.1j), which indicates only 3 Ω charge-transfer resistance owing to facile motion of the electrolyte ions. In conclusion, we report a facile method to increase the capacitance of micro-supercapacitors with laser-induced graphene electrodes. The method only requires the addition of one redox-active component to the electrolyte. Combined with the one-step fabrication and patterning of graphene by LIG, this method shows promise for low-cost flexible energy storage devices. Figure 1

We propose a single-beam leaky-wave antenna (LWA) with a wide-scanning angle and a high-scanning rate based on spoof surface plasmon polariton (SSPP) in this paper. The SSPP transmission line (TL) is etched with periodically arranged circular patches, which converts the slow-wave mode into the fast-wave region for radiation. The proposed LWA is designed, fabricated, and tested. The simulated results imply that the proposed LWA not only achieves a high radiation efficiency of about 81.4%, and a high scanning rate of 12.12, but also has a large scanning angle of 176° over a narrow operation bandwidth of 8.3–9.6 GHz (for |S 11| < –10 dB). In addition, the simulated average gain of the LWA can reach as high as 10.9 dBi. The measured scanning angle range is 175° in the operation band of 8.2–9.6 GHz, and the measured average gain is 10.6 dBi. The experimental results are consistent with the simulation, validating its performance. An antenna with high radiation efficiency, wide scanning angle range, and high scanning rate has great potential for application in radar and wireless communication systems.

Deconvolution of potentiometric SECM images recorded with high scan rate

Modification of the microstructure of ZE41A-T5 magnesium alloy substrates was investigated by laser surface re-melting and solidification using a 2.5 kW Nd:YAG laser. The effects of laser power, high scan rate and beam configuration were examined. The microstructure of laser treated ZE41 consisted of small precipitates dispersed in a fine dendritic α-magnesium matrix at high scan rates. The redistribution of chemical elements depended mainly on the dwell time in the liquid stage. At high scan rates, long dwell times were achieved by splitting the laser beam into two spots trailing in the scan direction which resulted in a more homogenous distribution of Mg, Zn and Zr. Cracking due to thermal shrinkage during solidification was prevented by reducing the temperature of the melt pool. This was achieved by lowering the laser power, increasing the scan rate and laser spot size. Increasing the laser spot size in the scan direction was conducive to producing homogeneous microstructures without cracks.