Differential Structure and Characteristics of a New-Type Silicon Magnetic Sensitivity Transistor

A differential structure magnetic sensor is proposed.It is comprised of two new-type silicon magnetic sensitivity transistors(SMSTs)with similar characteristics and has a common emitter,two bases and two collectors.The sensor is fabricated by micro electromechanical system technology on a<100>high resistivity silicon wafer.At room temperature,when supply voltage VDD=10.0 V,all the base currents Ib1 of SMST1 and Ib2 of SMST2 equal 6.0 mA,the absolute magnetic sensitivity for the two SMSTs are 46.8 mV/kG and 56.1 mV/kG,respectively,and the absolute magnetic sensitivity for the sensor is 102.9 mV/kG.Meanwhile,the temperature coefficientαV of the collector output voltage of the sensor is 0.044%/℃.The experimental results show that the magnetic sensitivity and the temperature characteristics of the sensor can be improved and ameliorated compared with a single SMST.

An ISS-OFDM based adaptive filtering mechanism for interference suppression in wireless multi-hop communication network

The negative impact on communication performance in wireless multi-hop communication net-work caused by limited bandwidth,high bit eror rate （BER）,fading,noise and interference is alleviated by an adaptive filtering game based on frequency subbands selection and predetemined threshold.Such threshold is being obtained in Gaussian and multipath fading channel according to the frequency-matching principle and BER performance.The dynamic selection of subbands will obtain high use efficiency without the help of frequency hopping,and propound a new thought to improve band limited communication for wireless multi-hop communication network.The effectiveness of the adaptive filtering method has been verified by interleaving spread spectrum orthogonal frequency division multiplexing （ISS-OFDM） in different interference conditions,and the simulating results based on network simulator 2 （NS2） indicate that system BER can be improved greatly.

Research on Low Energy Consumption Distributed Fault Detection Mechanism in Wireless Sensor Network

Wireless sensor network is an important technical support for ubiquitous communication. For the serious impacts of network failure caused by the unbalanced energy consumption of sensor nodes, hardware failure and attacker intrusion on data transmission, a low energy consumption distributed fault detection mechanism in wireless sensor network(LEFD) is proposed in this paper. Firstly, the time correlation information of nodes is used to detect fault nodes in LEFD, and then the spatial correlation information is adopted to detect the remaining fault nodes, so as to check the states of nodes comprehensively and improve the efficiency of data transmission. In addition, the nodes do not need to exchange information with their neighbor nodes in the initial detection process since LEFD adopts the data sensed by node itself to detect some types of faults, thus reducing the energy consumption of nodes effectively. Finally, LEFD also considers the nodes that may have transient faults. Performance analysis and simulation results show that the proposed detection mechanism can improve the transmission performance and reduce the energy consumption of network effectively.

Research on Link Duration for Mobile Multihop Communication Networks

Mobile multihop communication network is an important branch of modern mobile communication system, and is an important technical support for ubiquitous communication. The random movement of the nodes makes the networking be more flexible, but the frequently changing topology will decrease the link duration between nodes significantly, which will increase the packets loss probability and affect the network communication performance. Aiming at the problem of declining link duration caused by nomadic characteristics in mobile multihop communication network, four link duration models for possible moving states are established based on different features in real networking process in this paper, which will provide reliable criterion for the optimal routing selection. Model analysis and simulation results show that the reliable route established by the proposed model will effectively extend the link duration, and can enhance the global stability of the mobile multihop information transmission, so as to provide new option to transmission reliability improvement for the mobile communication network.

Resonances for positron–helium and positron–lithium systems in kappa-distribution plasma

S-wave resonances of positron–helium and positron–lithium systems in kappa-distribution plasmas are investigated using Hylleraas-type wave functions in the framework of the stabilization method. A model potential approach is used to represent the interactions between the outer electron, the positron and the core. The resonance parameters(position and width) of positron–helium and positron–lithium systems below the Ps(2s) threshold are reported as a function of screening parameter and spectral index of plasma.

High Sensitivity Magnetic Field Sensors Based on Nano-Polysilicon Thin-Film Transistors

A high-sensitivity magnetic field sensor based on the nano-polysilicon thin film transistors is proposed to adopt the nano-polysilicon thin films and the nano-polysilicon/single silicon heterojunction interfaces as the sensing layers.By using CMOS technology,the fabrication of the nano-polysilicon thin film transistors with Hall probes can be achieved on the<100>high resistivity single silicon substrates,in which the thicknesses of the nano-polysilicon thin films are 120 nm and the length width ratio of the channel is 320μm/80μm.When V_(DS)=5.0 V,the magnetic sensitivity and linearity is 264 mV/T and 0.23%f.s.(full scale),respectively.The experimental results show that the magnetic sensors based on nano-polysilicon thin film transistors with Hall probes exhibit high sensitivity.

Synchronous regulation of morphology and electronic structure of FeNi-P nanosheet arrays by Zn implantation for robust overall water splitting

FeNi-based phosphides are one of the most hopeful electrocatalysts,whereas the significant challenge is to achieve prominent bifunctional catalytic activity with low voltage for water splitting.The morphology and electronic structure of FeNi-based phosphides can intensively dominate effective catalysis,therefore their simultaneous regulating is extremely meaningful.Herein,a robust bifunctional catalyst of Zn-implanted FeNi-P nanosheet arrays(Zn-FeNi-P)vertically well-aligned on Ni foam is successfully fabricated by Zn implanting strategy.The Zn fulfills the role of electronic donor due to its low electronegativity to enhance the electronic density of FeNi-P for optimized water dissociation kinetics.Meanwhile,the implantation of Zn into FeNi-P can effectively regulate morphology of the catalyst from thick and irregular nanosheets to ultrathin lamellar structure,which generates enriched catalytic active sites,leading to accelerating electron/mass transport ability.Accordingly,the designed Zn-FeNi-P catalyst manifests remarkable hydrogen evolution reaction(HER)activity with low overpotentials of 55 and 225 mV at 10 and 200 mA·cm^(−2),which is superior to the FeNi-P(82 mV@10 mA·cm^(−2)and 301 mV@200 mA·cm^(−2)),and even out-performing the Pt/C catalyst at a high current density>200 mA·cm^(−2).Moreover,the oxygen evolution reaction(OER)activity of Zn-FeNi-P also has dramatically improved(207 mV@10 mA·cm^(−2))comparable to FeNi-P(221 mV@10 mA·cm^(−2))and RuO_(2)(239 mV@10 mA·cm^(−2)).Noticeably,an electrolyzer based on Zn-FeNi-P electrodes requires a low cell voltage of 1.47 V to achieve 10 mA·cm^(−2),far beyond the catalytic activities of FeNi-P||FeNi-P(1.51 V@10 mA·cm^(−2))and the benchmark RuO_(2)||Pt/C couples(1.56 V@10 mA·cm^(−2)).This Zn-implanting strategy paves a new perspective for the development of admirable bifunctional catalysts.

Fabrication and characteristics of the nc-Si/c-Si heterojunction MAGFET

A MAGFET using an nc-Si/c-Si heterojunction as source and drain was fabricated by CMOS technology, using two ohm-contact electrodes as Hall outputs on double sides of the channel situated 0.7L from the source. The experimental results show that when VDS = -7.0 V, the magnetic sensitivity of the single nc-Si/c-Si heterojunction magnetic metal oxide semiconductor field effect transistor （MAGFET） with an L ： W ratio of 2 ： 1 is 21.26 mV/T, and that with an L ： W ratio of 4 ： 1 is 13.88 mV/T. When the outputs of double nc-Si/c-Si heterojunction MAGFETs with an L ： W ratio of 4 ： 1 are in series, their magnetic sensitivity is 22.74 mV/T, which is an improvement of about 64% compared with that of a single nc-Si/c-Si heterojunction MAGFET.

Temperature characteristics research of SOI pressure sensor based on asymmetric base region transistor

Based on the asymmetric base region transistor, a pressure sensor with temperature compensation circuit is proposed in this paper. The pressure sensitive structure of the proposed sensor is constructed by a C-type silicon cup and a Wheatstone bridge with four piezoresistors（R_1, R_2, R_3 and R_4/locating on the edge of a square silicon membrane. The chip was designed and fabricated on a silicon on insulator（SOI） wafer by micro electromechanical system（MEMS） technology and bipolar transistor process. When the supply voltage is 5.0 V, the corresponding temperature coefficient of the sensitivity（TCS） for the sensor before and after temperature compensation are -1862 and -1067 ppm/℃, respectively. Through varying the ratio of the base region resistances r_1 and r_2, the TCS for the sensor with the compensation circuit is -127 ppm/℃. It is possible to use this compensation circuit to improve the temperature characteristics of the pressure sensor.

Fabrication and characteristics of magnetic field sensors based on nano-polysilicon thin-film transistors

A magnetic field sensor based on nano-polysilicon thin films transistors(TFTs) with Hall probes is proposed.The magnetic field sensors are fabricated on <100> orientation high resistivity(ρ>500Ω·cm) silicon substrates by using CMOS technology,which adopt nano-polysilicon thin films with thicknesses of 90 nm and heterojunction interfaces between the nano-polysilicon thin films and the high resistivity silicon substrates as the sensing layers.The experimental results show that when V_(DS) = 5.0 V,the magnetic sensitivities of magnetic field sensors based on nano-polysilicon TFTs with length-width ratios of 160μm/80μm,320μm/80μm and 480μm/80μm are 78 mV/T,55 mV/T and 34 mV/T,respectively.Under the same conditions,the magnetic sensitivity of the obtained magnetic field sensor is significantly improved in comparison with a Hall magnetic field sensor adopting silicon as the sensing layers.

Fabrication and characterization of the split-drain MAGFET based on the nano-polysilicon thin film transistor

A split-drain magnetic field-effect transistor （MAGFET） based on a nano-polysilicon thin film transistor （TFT） is proposed, which contains one source, two drains and one gate. The sensor chips were fabricated on （100） high resistivity silicon substrate by CMOS technology. When drain-source voltage equals 5.0 V and length and width ratio of the TFT channel is 80 μm/160 μm, the current and voltage magnetic sensitivities of the split-drain MAGFET based on the TFT are 0.018 mA/T and 55 mV/T, respectively. Through adopting nano-polysilicon thin films and nano-polysilicon thin films/high resistivity silicon heterojunction interfaces as the magnetic sensing layers, it is possible to realize detection of the external magnetic field. The test results show that magnetic sensitivity of the split-drain MAGFET can be improved significantly.

Influence of surface roughness on surface plasmon resonance phenomenon of gold film

We experimentally investigate the effects of the surface roughness of gold thin films on the properties of surface plasmon resonance. By annealing at different temperatures, film samples with different surface morphologies are obtained. Specifically, due to the diffusion of the gold atoms towards the films＇ surface, the surface root- mean-square roughness decreases with the increasing annealing temperature. Then, we measure the surface plasmon resonance of the samples. The results show that the resonance angle of the surface plasmon resonance is sensitive to the root-mean-square roughness, and it gradually decreases by reducing the surface root-mean-square roughness.

Switchable optical nonlinear properties of W_(18)O_(49) nanowires by Ag nanoparticles supported

During the past decades,nonlinear optical（NLO）materials have attracted special interest because of their potential applications in photonic devices,such as optical switching,frequency conversion and electro-optic modulators.Among the finding ways to obtain excellent NLO materials with both large NLO response and short response time,

Photo Responsive Silver Nanoparticles Incorporated Liquid Crystalline Elastomer Nanocomposites Based on Surface Plasmon Resonance

We reported a nano-Ag/liquid crystalline elastomer（LCE） nanocomposite by incorporating silver nanopar- ticles into a monodomain polysiloxane-based LCE matrix via a novel experimental protocol. The photo-thermo- mechanical actuation of the LCE matrix was realized via the surface plasmon resonance of silver nanoparticles while converting light into heat. The photoresponsive properties of nano-Ag/LCE nanocomposites were investigated with varying ilhunination intensities and silver nanoparticle doping concentrations（0.04% to 0.2%, mass fraction）. The nano-Ag/LCE nanocomposites show sensitive deformation under irradiation due to their excellent photothermal con- version efficiency, and this photostimulated muscle-like actuation is fully reversible via the on-off behavior of light. Incorporating silver nanoparticles into the LCE matrix also improves the mechanical properties and enhances the load-actuation capability of the material.