Photocatalytic activity and radiation-attenuation ability of copper ions surface-doped dysprosium oxide

Journal of Materials Science: Materials in Electronics - Herein, Cu ions surface-doped Dy2O3 photocatalyst (Cu–Dy2O3) is synthesized utilizing hydrothermal technique to degrade methyl violet...     

Enhancement of electrical properties by including nano-aluminum nitride to micro-silicon carbide/silicone elastomer composites for potential power module packaging applications

This paper reports an enhancement of the electrical properties of micro-silicon carbide/silicone elastomer (m-SiC/SE) composites by adding nano-aluminum nitride (n-AlN) for the next-generation power module encapsulation applications. The electrical properties, such as nonlinear conductivity, DC breakdown strength, dielectric spectroscopy, and thermally stimulated discharge current, of the pure SE, m-SiC/SE microcomposite, and m-SiC/n-AlN/SE hybrid composites added with 1 wt%, 3 wt%, and 5 wt% n-AlN fillers are investigated. The m-SiC/n-AlN/SE hybrid composites exhibit better nonlinear conductivity characteristics and enhanced DC breakdown strength than the m-SiC/SE microcomposite. Amongst all materials, the 3 wt% n-AlN addition in the hybrid composite has the best enhancement effect on the nonlinear conductivity characteristics and DC breakdown strength. However, it has the lowest low-frequency real and imaginary permittivities among the SE micro and hybrid composites. Furthermore, a m-SiC/n-AlN heterogenous interface model is proposed to explain the mechanism of enhanced electrical properties of the m-SiC/n-AlN/SE composites. It is found that higher m-SiC/n-AlN heterogenous interface barriers are constructed after adding n-AlN fillers, thereby inhibiting the charge carrier transport at low electric fields. In contrast, more conductive paths are activated at high electric fields by the contacted m-SiC fillers via n-AlN fillers, promoting the charge carrier transport at high electric fields.

     

Structural,optical and dielectric properties of aluminum-substituted SrAl2xFe12-2xO19 x = (0.0,0.2,0.4,0.6,0.8,1.0) M-type hexagonal ferrites

Journal of Materials Science: Materials in Electronics - Aluminum-substituted M-type hexaferrites with nominal composition SrAl2xFe12-2xO19 with x?=?(0.0,0.2,0.4,0.6,0.8,1.0) were...     

Novel NiO/ZnO/Fe2O3 white light-emitting phosphor: facile synthesis,color-tunable photoluminescence and robust photocatalytic activity

Journal of Materials Science: Materials in Electronics - The NiO/ZnO/Fe2O3 ternary nanocomposites with different molar ratios (1:1:1), (2:1:1), (3:1:1) and (4:1:1) were synthesized by...     

An enhanced approach for the progressive mean control charts

To maintain and improve the quality of the processes, control charts play an important role for reduction of variation. To detect large shifts in the process parameters, Shewhart control charts are commonly applied but for small shifts, exponentially weighted moving averages (EWMA), cumulative sum (CUSUM), double exponentially weighted moving average (DEWMA), double CUSUM, moving average (MA), double moving average (DMA), and progressive mean (PM) control charts, are used. This study proposes double progressive mean (DPM) and optimal DPM control charts to enhance the performance of the PM chart. As the proposed DPM control charts use information sequentially, hence their performance is compared with natural competitors EWMA, CUSUM, DEWMA, double CUSUM, MA, DMA, and PM control charts. Run length and its different properties are evaluated to compare the performance of the proposed charts and counterparts. Results reveal that proposed optimal DPM outperforms the other charts. An example related to voltage on fixed capacitance level is also provided to illustrate the proposed charts.     

An efficient double exponentially weighted moving average Benjamini‐Hochberg control chart to control false discovery rate

A control chart based on double exponentially weighted moving average and Benjamini‐Hochberg multiple testing procedure is proposed that controls the false discovery rate (FDR). The proposed control chart is based on probabilities (or P values) to accept or reject the null hypothesis of the underlying process is in control. To make a decision, instead of using only the current probability, previous “m” probabilities are considered. The performance of the control chart is evaluated in terms of average run length (ARL) using Monte Carlo simulations. Procedure for estimation of parameters used in the control chart is also discussed. The proposed control chart is compared with previous control charts and found to be more efficient in controlling the false discovery rate.     

Tailoring Nanomaterials for Targeting Tumor‐Associated Macrophages

Advances in the field of nanotechnology together with an increase understanding of tumor immunology have paved the way for the development of more personalized cancer immuno‐nanomedicines. Nanovehicles, due to their specific physicochemical properties, are emerging as key translational moieties in tackling tumor‐promoting, M2‐like tumor‐associated macrophages (TAMs). Cancer immuno‐nanomedicines target TAMs primarily by blocking M2‐like TAM survival or affecting their signaling cascades, restricting macrophage recruitment to tumors and re‐educating tumor‐promoting M2‐like TAMs to the tumoricidal, M1‐like phenotype. Here, the TAM effector mechanisms and strategies for targeting TAMs are summarized, followed by a focus on the mechanistic considerations in the development of novel immuno‐nanomedicines. Furthermore, imaging TAMs with nanoparticles so as to forecast a patient's clinical outcome, describing treatment options, and observing therapy responses is also discussed. At present, strategies that target TAMs are being investigated not only at the basic research level but also in early clinical trials. The significance of TAM‐targeting biomaterials is highlighted, with the goal of facilitating future clinical translation.     

Compact triband slotted printed monopole antenna for WLAN and WiMAX applications

This work presents a triband antenna, which is compact, low profile, and covers the bandwidth requirements for WLAN and WiMAX applications. The proposed design is a modified and miniaturized printed monopole antenna. It consists of beveling rectangular patch, a Pi‐shape slot element, and an inverted‐L slot element to achieve resonance in three bands. The physical size of the antenna is 27.5 × 20 mm² while the electrical size is 0.26 λ₀ × 0.23 λ₀ at the lower operating frequency which is very compact as compared to other triband designs. It works in three bands, that is, 2.37 to 2.52 GHz, 3.35 to 3.90 GHz, and 4.97 to 7.85 GHz with |S₁₁| < ? 10 dB within these operating bands. The prototype of the proposed miniaturized antenna has been fabricated and the measured results are provided for validation. Antenna performance is studied in terms of input match, gain, radiation efficiency, surface current distributions, and radiation pattern. The antenna shows a nearly omnidirectional radiation pattern with peak efficiency of 90% and acceptable gain of 4 dBi over the three operating bands of WLAN and WiMAX. The prototype of the antenna is fabricated, and simulated results have been verified through measurements.     

Analysis and design of a stacked power amplifier with 196% fractional bandwidth using equivalent circuit model

Stacked structure is a good solution to overcome the low output voltage swing provided by a single device. When several devices are stacked, the bandwidth and output power are multiple times higher. This article analyzes the small‐signal voltage gain of the stacked structure, deriving the gain expression of the high‐frequency model and simplified model. Based on the specific device parameter, the different small‐signal voltage gains between the two models are compared and the designed stacked structure is proved to obtain a flat gain at low frequencies below about 3 GHz. To our best knowledge, this is the first article to analyze the gain flatness of stacked structure with two equivalent circuit models. To verify the stacked theory, a pseudomorphic high‐electron‐mobility transistor（PHEMT） power amplifier (PA) is implemented using 0.25 μm Gallium arsenide (GaAs) technology. The PA achieves an ultra‐high bandwidth of 30 MHz to 3 GHz and a linear gain of 21 dB ± 1.5 dB. At a 16‐V drain bias voltage, a saturated output power of higher than 2 W and a peak power‐added efficiency (PAE) of 44.1% are attained.     

A WLAN band‐notched compact four element UWB MIMO antenna

A compact four‐element multiple‐input‐multiple‐output (MIMO) antenna for ultra‐wideband (UWB) applications with WLAN band‐notched characteristics is proposed here. The proposed antenna has been designed to operate from 2 to 12 GHz while reject the frequencies between 4.9 to 6.4 GHz. The four antenna elements are placed orthogonal to attain the polarization diversity and high isolation. A thin stub connected to the ground plane is deployed as a LC notch filter to accomplish the rejected WLAN band in each antenna element. The mutual coupling between the adjacent elements is at least 17 dB while it has low indoor and outdoor envelop correlation (<0.45) and high gain with compact size of two boards, each measuring 50 × 25 mm². To validate the concept, the prototype antenna is manufactured and measured. The comparison of the simulation results showed good agreement with the measured results. The low‐profile design and compact size of the proposed MIMO antenna make it a good candidate for diversity applications desired in portable devices operating in the UWB region.