Flexible Transparent Reduced Graphene Oxide Sensor Coupled with Organic Dye Molecules for Rapid Dual‐Mode Ammonia Gas Detection

Flexible chemical sensors utilizing chemically sensitive nanomaterials are of great interest for wearable sensing applications. However, obtaining high performance flexible chemical sensors with high sensitivity, fast response, transparency, stability, and workability at ambient conditions is still challenging. Herein, a newly designed flexible and transparent chemical sensor of reduced graphene oxide (R‐GO) coupled with organic dye molecules (bromophenol blue) is introduced. This device has promising properties such as high mechanical flexibility (>5000 bending cycles with a bending radius of 0.95 cm) and optical transparency (>60% in the visible region). Furthermore, stacking the water‐trapping dye layer on R‐GO enables a higher response as well as workability in a large relative humidity range (up to 80%), and dual‐mode detection capabilities of colorimetric and electrical sensing for NH₃ gas (5–40 ppm). These advantageous attributes of the flexible and transparent R‐GO sensor coupled with organic dye molecules provide great potential for real‐time monitoring of toxic gas/vapor in future practical chemical sensing at room conditions in wearable electronics.     

Ionic Modulation of Interfacial Magnetism in Light Metal/Ferromagnetic Insulator Layered Nanostructures

Ferromagnetic insulator thin film nanostructures are becoming the key component of the state‐of‐the‐art spintronic devices, for instance, yttrium iron garnet (YIG) with low damping, high Curie temperature, and high resistivity is explored into many spin–orbit interactions related spintronic devices. Voltage modulation of YIG, with great practical/theoretical significance, thus can be widely applied in various YIG‐based spintronics effects. Nevertheless, to manipulate ferromagnetism of YIG through electric field (E‐field), instead of current, in an energy efficient manner is essentially challenging. Here, a YIG/Cu/Pt layered nanostructure with a weak spin–orbit coupling interaction is fabricated, and then the interfacial magnetism of the Cu and YIG is modified via ionic liquid gating method significantly. A record‐high E‐field‐induced ferromagnetic resonance field shift of 1400 Oe is achieved in YIG (17 nm)/Cu (5 nm)/Pt (3 nm)/ionic liquid/Au capacitor layered nanostructures with a small voltage bias of 4.5 V. The giant magnetoelectric tunability comes from voltage‐induced extra ferromagnetic ordering in Cu layer, confirmed by the first‐principle calculation. This E‐field modulation of interfacial magnetism between light metal and magnetic isolator may open a door toward compact, high‐performance, and energy‐efficient spintronic devices.     

Neural networks with higher-order nonlinearity

Neural networks for associative memory based on the Hopfield relaxation model and matched filtering techniques with higher-order nonlinearity are proposed. These high-order models show dramatic improvement in memory storage capacity and error-correction capability in comparison to conventional binary autoassociative models     

AlN-SiC微波衰减陶瓷在X波段的选频衰减性能

以氮化铝、碳化硅为原料,氧化钇为烧结助剂,在1900℃、氮气气氛中,采用热压烧结工艺制备了AlN-SiC复相微波衰减材料。借助网络分析仪,研究了该材料在8~12GHz的微波衰减性能。结果表明,当SiC质量分数从0增加到9%时,该材料的谐振损耗峰所对应的频率从10.86GHz降低到10.11GHz,所对应的峰值从3.2dB降低到0.7dB,而该材料的有效衰减带增大;在900~1000℃、氢气(纯度≥99.99%)气氛中保温30~50min后,该材料的谐振频率维持在10.65~10.62GHz,谐振峰峰值略微减小;这表明在氢气气氛中的热处理对该材料的微波衰减性能影响较小。     

Noise removal using fourth-order partial differential equation with applications to medical magnetic resonance images in space and time

We introduce a new method for image smoothing based on a fourth-order PDE model. The method is tested on a broad range of real medical magnetic resonance images, both in space and time, as well as on nonmedical synthesized test images. Our algorithm demonstrates good noise suppression without destruction of important anatomical or functional detail, even at poor signal-to-noise ratio. We have also compared our method with related PDE models.     

添加CuO对Ba_(3.99)Sm_(9.34)Ti_(18)O_(54)陶瓷烧结及微波介电性能的影响

采用传统固相工艺制备了Ba3.99Sm9.34Ti18O54(BSTO)微波介质陶瓷,研究了烧结助剂CuO对BSTO的结构及介电性能的影响。结果表明,添加CuO能较好促进BSTO晶粒致密化,降低烧结温度约140℃。当添加质量分数1.0%的CuO时,1220℃保温3h烧结的BSTO样品的介电性能较好:εr=86.87,Q·f=5138GHz(f=4.95GHz),τf=–10.84×10–6℃–1。     

基于Web的中小企业客户关系管理系统规划与实现

我国中小企业与大型企业相比具有规模小,技术、资金、人才缺乏等特点,因此中小企业CRM必须具备傻瓜化的特点:功能尽可能简单、实用,实施周期一定要短,维护方便,价格便宜。本文根据以上要求提出了基于B/S(Browser/Server)模式的中小企业客户关系管理系统(ZXCRM),就CRM系统的业务架构,工作流程,实现的关键技术,系统平台的功能和体系结构等问题进行了深入研究,并给出了系统实现的应用实例。     

光泵腔式NH3分子亚毫米波激光的调谐特性研究

通过求解量子系统的密度矩阵方程，计算了不同管长和不同输入输出功率反射系数的光泵腔式激光器对281um和90.4um的亚毫米波信号的调谐特性，给出了其调谐特性随信号波长λ，激光管长l和功率反射系数R的变化关系。     

X射线荧光光谱法分析镁铬耐火材料

采用熔融的方法进行制样,并以标准样品和高纯试剂配制熔融的系列标准玻璃片来建立校准曲线,用X射线荧光光谱法测定镁铬耐火材料中Na、Mg、Al、Si、Cr等11个元素。结果表明:该方法有效地克服了镁铬系列耐火材料存在的矿物效应和颗粒效应,方法简单,快速,准确。当试样中Na2O、MgO、Al2O3、SiO2和Cr2O3的质量分数分别为0.47%、40.00%、8.24%、11.84%和27.07%时,其测定结果的相对标准偏差分别为4.04%、0.25%、0.32%、0.46%和0.24%;本方法的测定值与化学分析法的测定值较一致,能满足常规分析的要求。     

A review on Ti3C2Tx-based nanomaterials:synthesis and applications in gas and humidity sensors

Ti3C2Tx,which is a novel two-dimensional (2D)material,has received enormous interest in the field of sensor technology due to its large surface area,excellent e...