Dual Mode Strain–Temperature Sensor with High Stimuli Discriminability and Resolution for Smart Wearables

Strain and temperature are important physiological parameters for health monitoring, providing access to the respiration state, movement of joints, and inflammation processes. The challenge for smart wearables is to unambiguously discriminate strain and temperature using a single sensor element assuring a high degree of sensor integration. Here, a dual-mode sensor with two electrodes and tubular mechanically heterogeneous structure enabling simultaneous sensing of strain and temperature without cross-talk is reported. The sensor structure consists of a thermocouple coiled around an elastic strain-to-magnetic induction conversion unit, revealing a giant magnetoelastic effect, and accommodating a magnetic amorphous wire. The thermocouple provides access to temperature and its coil structure allows to measure impedance changes caused by the applied strain. The dual-mode sensor also exhibits interference-free temperature sensing performance with high coefficient of 54.49 µV °C⁻¹, low strain and temperature detection limits of 0.05% and 0.1 °C, respectively. The use of these sensors in smart textiles to monitor continuously breathing, body movement, body temperature, and ambient temperature is demonstrated. The developed multifunctional wearable sensor is needed for applications in early disease prevention, health monitoring, and interactive electronics as well as for smart prosthetics and intelligent soft robotics.     

Quality‐of‐service guarantees architecture with weighted fair shaping

Weighted Fair Queuing (WFQ), conducted for each flow at ATM nodes, is effective for ensuring fairness among differently behaving flows, and for preventing incremental delay as cells are transmitted through multiple nodes. Implemented thus in accordance with rates assigned to flows and actual cell transmission conditions, WFQ is known as “shaping”. This paper proposes a new installable algorithm that dynamically adapts WFQ to each of multiple flows. The Quality‐of‐Service (QoS) guaranteed by this algorithm is also explained. This revised version was published online in June 2006 with corrections to the Cover Date.     

Optimization Design of Superluminescent Diodes with RWGStructure for High Efficiency Coupling with SMFs

为了提高脊波导结构的超辐射二极管（SLD）与单模光纤的耦合功率，研究了有源区与脊之间的残留层和上光限制层的厚度对SLD输出功率和近场光斑的影响. 考虑了注入载流子横向分布的不均匀，较准确地计算了模式增益. 结果表明，通过对残留层和上光限制层厚度的优化，可以有效提高SLD与单模光纤的耦合功率.     

Correlation of Electrical Noise with Non—radiative Current for High Power QWLs

The characteristics of low-frequency electrical noise, voltage-current (V-I) and electrical derivation for 980 nm InGaAsP/InGaAs/GaAs high power double quantum well lasers (DQWLs) are measured under different conditions.The correlation of the low-frequency electrical noise with surface non-radiative current of devices is discussed.The results indicate the low-frequency electrical noise of 980 nm DQWLs with high power is mainly 1/? noise and has good relation with the device surface current at low injection.     

Surface Reflection Coefficient of Impregnated RAM Honeycomb with Incident Normally Plan Wave to the Side Wall

Impregnated radar absorbing material(RAM) honeycomb is one of the most useful material for fabricating parts of modern war plane by taking advantages of its light weight, highly mechanical strength and highly absorbing characteristics. It may be used to fabricate vertical tail-wing, front edge of wing or the wing of cruiser missile, etc. The RAM used is usually non-magnetic material for lowering the weight. The reflection characteristics of the impregnated RAM honeycomb with its open end a…     

AlGaN/GaN High Electron Mobility Transistors on Sapphires with fmax of 100GHz

制作了蓝宝石衬底上生长的AlGaN/GaN高电子迁移率晶体管.0V栅压下,0.3μm栅长、100μm栅宽的器件的饱和漏电流密度为0.85A/mm,峰值跨导为225mS/mm;特征频率和最高振荡频率分别为45和100GHz;4GHz频率下输出功率密度和增益分别为1.8W/mm和9.5dB,8GHz频率下输出功率密度和增益分别为1.12W/mm和11.5dB.     

AlGaN Nanostructures with Extremely High Room-Temperature Internal Quantum Efficiency of Emission Below 300 nm

We present theoretical optimization of the design of a quantum well (QW) heterostructure based on AlGaN alloys, aimed at achievement of the maximum possible internal quantum efficiency of emission in the mid-ultraviolet spectral range below 300 nm at room temperature. A sample with optimized parameters was fabricated by plasma-assisted molecular beam epitaxy using the submonolayer digital alloying technique for QW formation. High-angle annular dark-field scanning transmission electron microscopy confirmed strong compositional disordering of the thus-fabricated QW, which presumably facilitates lateral localization of charge carriers in the QW plane. Stress evolution in the heterostructure was monitored in real time during growth using a multibeam optical stress sensor intended for measurements of substrate curvature. Time-resolved photoluminescence spectroscopy confirmed that radiative recombination in the fabricated sample dominated in the whole temperature range up to 300 K. This leads to record weak temperature-induced quenching of the QW emission intensity, which at 300 K does not exceed 20% of the low-temperature value.     

Synthesis and Assembly of Core–Shell Nanorods with High Quantum Yield and Linear Polarization

The seeded growth method offers an efficient way to design core–shell semiconductor nanocrystals in the liquid phase. The combination of seed and shell materials offers wide tunability of morphologies and photophysical properties. Also, semiconductor nanorods (NRs) exhibit unique polarized luminescence which can potentially break the theoretical limit of external quantum efficiency in light emitting diodes based on spherical quantum dots. Although rod-in-rod core–shell NRs present higher degree of polarization, most studies have focused on dot-in-rod core–shell NRs due to the difficulties in achieving uniform NR seeds. Here, this study prepares high-quality uniform CdSe NRs by improving the reactivity of the Se source, using a secondary phosphine, namely diphenylphosphine, to dissolve the Se power, along with the conventional tertiary phosphine, namely trioctylphosphine. Starting from these high-quality NR seeds, this study synthesizes CdSe/Cd_xZn_1−xS/ZnS core–shell NRs with narrow emission bandwidth (29 nm at 620 nm), high PLQY (89%) and high linear polarization (p = 0.90). This study then assembles these core–shell NRs using the confined assembly method and fabricates long-range-ordered microarrays with programmable patterns and displaying highly polarized emission (p = 0.80). This study highlights the great potential of NRs for application in liquid crystal displays and full-color light emitting diodes displays.     

Surface Impedance of the “Thick Ice–Sea” Structure in the Radio Wave Range from Very Low to Very High Frequencies

Journal of Communications Technology and Electronics - In this paper, the scope of applicability of impedance boundary conditions for a vertically polarized wave in the 0.01–120 MHz frequency...     

Performance of a joint CDMA/PRMA protocol with heavy‐tailed ON/OFF source

The performance of a joint CDMA/PRMA protocol with heavy-tailed ON/OFF source has been studied. Compared with the random access scheme, the PRMA protocol improves the system performance (such as packet loss, throughput) whether the traffic is SRD or LRD. The less bursty traffic is, the greater the improvement. The buffer design should take into account knowledge about the network traffic such as the presence or absence of the Noah effect in a typical source, especially of _on, the intensity of the Noah effect of ONperiod. The smaller _on is, the smaller the buffering gain, and the more packets will be lost. LRD has impacts on the overall system performance. The Noah effect, especially _off, the intensity of the Noah effect of OFFperiod, has significant impact on the overall system performance such as capacity, time delay, etc. As _off gets closer to 1, the traffic becomes more bursty, the system capacity is decreased and time delay is increased.     

Realization of an 850V High Voltage Half Bridge Gate Drive IC with a New NFFP HVI Structure

A NFFP HVI structure which implements high breakdown voltage without using additional FFP and process steps is proposed in this paper. An 850 V high voltage half bridge gate drive IC with the NFFP HVI structure is experimentally realized using a thin epitaxial BCD process. Compared with the MFFP HVI structure, the proposed NFFP HVI structure shows simpler process and lower cost. The high side offset voltage in the half bridge gate drive IC with the NFFP HVI structure is almost as same as that with the self-shielding structure.     

In Situ Deformation Topology of COFs with Shortened Channels and High Redox Properties for Li–S Batteries

Covalent organic frameworks (COFs) with various topologies are typically synthesized by selecting and designing connecting units with rich shapes. However, this process is time-consuming and labour-intensive. Besides, the tight stacking of COFs layers greatly restrict their structural advantages. It is crucial to effectively exploit the high porosity and active sites of COFs by topological design. Herein, for the first time, inducing in situ topological changes in sub-chemometric COFs by adding graphene oxide (GO) without replacing the monomer, is proposed. Surprisingly, GO can slow down the intermolecular stacking and induce rearrangement of COFs nanosheets. The channels of D- [4+3] COFs are significantly altered while the stacking of periodically expanded framework is weakened. This not only maximizes the exposure of pore area and polar groups, but also shortens the channels and increases the redox activity, which enables high loading while enhancing host-guest interactions. This topological transformation to exhibit the structural features of COFs for efficient application is an innovative molecular design strategy.     

Rapid Sintering of Silica Xerogel Ceramic Derived from Sago Waste Ash Using Sub-millimeter Wave Heating with a 300 GHz CW Gyrotron

In this paper, we present and discuss experimental results from a microwave sintering of a silica-glass ceramic, produced from a silica xerogel extracted from a sago waste ash. As a radiation source for the microwave heating a sub-millimeter wave gyrotron (Gyrotron FU CW I) with an output frequency of 300 GHz has been used. The powders of silica xerogel have been dry pressed and then sintered at temperatures ranging from 300°C to 1500°C. The influence of the sintering temperature on the technological properties such as porosity and bulk density was studied in detail. Furthermore, X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy have been used in order to study the structure of the produced silica glass-ceramics. It has been found that the silica xerogel crystallizes at a temperature of 800°C, which is about 200°C lower than the one observed in the conventional process. The silica xerogel samples sintered by their irradiation with a sub-millimeter wave at 900°C for 18 minutes are fully crystallized into a silica glass-ceramic with a density of about 2.2 g/cm³ and cristobalite as a major crystalline phase. The results obtained in this study allow one to conclude that the microwave sintering with sub-millimeter waves is an appropriate technological process for production of silica glass-ceramics from a silica xerogel and is characterized with such advantages as shorter times of the thermal cycle, lower sintering temperatures and higher quality of the final product.     

Linker Defects in Metal–Organic Frameworks for the Construction of Interfacial Dual Metal Sites with High Oxygen Evolution Activity

Designing efficient electrocatalysts based on metal–organic framework (MOF) nanosheet arrays (MOFNAs) with controlled active heterointerface for the oxygen evolution reaction (OER) is greatly desired yet challenging. Herein, a facile strategy for the synthesis of MOF-based nanosheet arrays (γ-FeOOH/Ni-MOFNA) is developed with abundant heterointerfaces between Ni-MOF and γ-FeOOH nanosheets by introducing linker defects to the former. The experimental and theoretical results show the key role of linker defects in inducing the growth of secondary γ-FeOOH nanosheets onto the surface of Ni-MOFNAs, which further leads to the formation of interfacial Ni/Fe dual sites with high oxygen evolution activity. Notably, the resulting γ-FeOOH/Ni-MOFNA exhibits excellent OER performance with low overpotentials of 193 and 222 mV at 10 and 100 mA cm⁻², respectively. Furthermore, the study of the structure–performance relationship of MOF-based heterostructures reveals that Ni sites at the interface of the γ-FeOOH/Ni-MOFNA have higher activity than those at the interface of NiFe layered double hydroxide and Ni-MOFNA. This study provides a new prospect on heterostructured electrocatalysts with highly active sites for enhanced OER.     

“One Stone Five Birds” Plasma Activation Strategy Synergistic with Ru Single Atoms Doping Boosting the Hydrogen Evolution Performance of Metal Hydroxide

Layered metal hydroxides (LMHs) are promising catalysts for oxygen evolution reaction. However, the hydrogen evolution reaction (HER) activity of LMHs is unsatisfactory due to their poor conductivity and limited active sites. Herein, taking Ni(OH)₂ as demonstration, a novel “one stone five birds” plasma activation strategy synergistic with Ru single atoms (Ru SAs) doping is developed to boost the HER activity of Ni(OH)₂ by constructing heterostructured β-Ni(OH)₂/Ni-Ru SAs nanosheet arrays (NSAs). Benefiting from the structural/compositional features and optimized electronic state, the as-obtained β-Ni(OH)₂/Ni-Ru SAs NSAs exhibit splendid HER activity with a low overpotential of 16 mV at 10 mA cm⁻² and a small Tafel slope of 21 mV dec⁻¹ in alkaline solution. Excellent HER performance in alkaline seawater and neutral solutions are also demonstrated by the β-Ni(OH)₂/Ni-Ru SAs NSAs. The plasma activation and Ru SAs doping play important roles in enhancing water adsorption and accelerating the kinetics of water dissociation. Density functional theory (DFT) calculations reveal that the introduction of Ru SAs in the system facilitates the generation of surface OH vacancies for providing more active sites as well as decreases the antibonding state density of the generated mid-gap state for enhancing H adsorption strength toward the optimal range.     

High purity InxGa1−xSb single crystals with cutoff wavelength of 7–8 µm grown by melt epitaxy

For the first time, InGaSb single crystals with a cutoff wavelength of 7–8 μm were successfully grown on GaAs substrates by a new growth technique named melt epitaxy. The band gap of InGaSb layers obviously narrowed compared with those with the same compositions grown by ordinary methods and the longest cutoff wavelength reached 8.3 μm. High electron mobility of 8.05×10⁴ cm²/Vs and low carrier density of 1×10¹⁵ cm⁻³ at 77 K were obtained indicating high purity of InGaSb epilayers.     

High Performance β-Ga2O3 Schottky Barrier Transistors with Large Work Function TMD Gate of NbS2 and TaS2

Gallium trioxide, β-Ga₂O₃, has been recently studied due to its promising semiconducting properties as active material in transistors or Schottky diodes. Transistors with β-Ga₂O₃ channels are mostly metal oxide field effect transistors (MOSFET), and they show very negative threshold voltages (V_th) in general. Metal semiconductor field effect transistors (MESFETs) with top gate are also reported with less negative V_th. Still, β-Ga₂O₃ MESFETs are only a few. Here, bottom gate architecture β-Ga₂O₃ MESFETs using transition metal dichalcogenide (TMD) NbS₂ and TaS₂ are reported. Due to the large work functions of those metallic TMDs, the MESFETs display minimum subthreshold swing of 61 mV dec⁻¹, small V_th of −1.2 V, minimum OFF I_D of ≈100 fA, and maximum ON/OFF current ratio of ≈10⁸. Both β-Ga₂O₃ Schottky diodes with TaS₂ and NbS₂ display good junction stability even after 300 °C measurements in 10 mTorr vacuum. When the β-Ga₂O₃ MESFET with TaS₂ gate is integrated as a switching FET into an organic light emitting diode (OLED) circuit, it demonstrates long-term leakage endurance performance, maintaining an OLED brightness higher than 58% of the initial intensity after 100 s passes since the ON-switching point, which is even superior to the performance of conventional a-IGZO MOSFET switch.     

A Stable Low Power Dissipating 9 T SRAM for Implementation of 4 × 4 Memory Array with High Frequency Analysis

Wireless Personal Communications - Today’s high speed data processing and memory storage operations demand immediate data write and retrieval to meet up to benchmark. To act as a volatile or...     

In Situ Synthesis of the Peapod-Like Cu–SnO2@Copper Foam as Anode with Excellent Cycle Stability and High Area Specific Capacity

The theoretical specific capacity of tin oxide (SnO₂) anode material is more than twice that of graphite material (782 vs 372 mAh g^–1), whereas its potential usage is limited fatally by its huge volume expansion during lithiation. An effective solution is to encapsulate tin oxide into hollow structure such as yolk-shell based on the principle of confinement. However, in light of the restricted space of active substance, this kind of hollow electrode always has the low capacity, severely limiting its commercial value. Herein, a peapod-like Cu-SnO₂@copper foam (CF) as high area specific capacity anode based on the Kirkendall effect, in which the “pod and peas” in the peapod-like structure are composed of SnO₂ and Cu nanoparticles, respectively, is tactfully designed and constructed. Compared to other SnO_x-based electrodes with different hollow structure designs in published reports, the unique peapod-like Cu-SnO₂@CF anode delivers a remarkably high first reversible capacity of 5.80 mAh cm^-2 as well as excellent cycle stability with 66.7% capacity retention and ≈100% coulombic efficiency after 200 cycles at a current density of 1 mA cm^–2, indicative of its quite promising application toward high-performance lithium-ion batteries.     

Metallic Zinc Anode Working at 50 and 50 mAh cm−2 with High Depth of Discharge via Electrical Double Layer Reconstruction

Achieving high-rate and high-areal-capacity Zn anode with high depth of discharge (DOD) offers a bright future for large-scale aqueous batteries. However, Zn deposition suffers from severe dendrite growth and side reactions, which compromises achievable lifetime. Herein, an electrical double layer (EDL) reconstruction strategy is proposed by employing acetone as electrolyte additive to fully address these issues. Experimental and theoretical simulation results reveal that the adsorption priority of acetone to water on Zn creates a water-poor inner Helmholtz layer. Meanwhile, the intense hydrogen bonding effect between acetone and water confines the activity of free water and weakens the Zn²⁺ solvation in the outer Helmholtz layer and diffusion layer. Such ion/molecule rearrangement in EDL suppresses hydrogen evolution, facilitates the desolvation process, and promotes the Zn²⁺ diffusion kinetics, which guides homogeneous Zn nucleation and uniform growth, even in extreme situations. At both ultrahigh current density of 50 mA cm⁻² and areal capacity of 50 mAh cm⁻², the addition of 20 v/v% acetone in 2 m ZnSO₄ extends the lifespan of Zn//Zn symmetric cells from 12 to 800 h, with a high DOD of 73.5%. The effectiveness of this strategy is further demonstrated in the Zn-MnO₂ full batteries at wide temperature range from −30 to 40 °C.