Microwave technology enabled transdermal nanocarrier and drug delivery

Transdermal drug delivery is impeded by the natural barrier of epidermis known as stratum corneum.This limits the route to transport of drugs with a log octanol–water partition coefficient of 1 to 3,molecular weight of less than 500 Da and melting point of less than 200°C.Nanotechnology has received a widespread investigation as the nanocarriers are able to fluidize the stratum corneum as a function of size,shape,surface charges,and hydrophilicity–hydrophobicity balance,while delivering drugs across the skin barrier.

Enhancing Production Efficiency of Oil and Natural Gas Pipes Using Microwave Technology

The research reported in this paper aims at developing means of Non Destructive testing (NDT) to increase the line efficiency of pipe production in oil and natural gas pipe manufacturing plants using the Standard Allowed Minutes (SAM) method. Existing line production stations encounter difficulties in maintaining the recommended testing speed of smaller diameter pipe, due to limitations in the Visual Inspection (VI) station. We propose to implement one additional technique which will prevent the decline of line efficiency in a pipe production factory. The range of diameters identified as a problem in this research is from 254 mm to 762 mm. Microwave techniques are expected to improve the line efficiency by increasing the production of the plant. This happens as a consequence of maintaining the production rates of the identified pipe diameters, so that they equal the production output of the larger pipe diameters. We analyze the velocity traveled by the pipe through Radiographic Testing (RT) according to the VI output (production). The RT velocity is decreased for the diameters identified above, in order to maintain quality control and cover the shortcoming of the VI. The number of pipes produced is computed during shift hours of the factory and pipe lengths of the forming department are determined. We compare the output (production) of a series of NDT line stations with and without the microwave technique for the first of the three pipe cases considered in this study, classified as perfect pipe (PP), repair pipe (RP) and scrap pipe (SP). The velocity of RT stations analyzed in the paper ranges from 50 mm/s for larger diameter pipe, and decline to 16.667 mm/s for the identified diameters. The analytical calculations of line output (production) and line efficiency demonstrate the solution of this velocity problem after the microwave technique is introduced. It demonstrates that an economical and precise methodology to extend the production capability of the pipe plant has been determined.

Zero-Index Metamaterial Superstrates UWB Antenna for Microwave Imaging Detection

Metamaterials(MTM)can enhance the properties of microwaves and also exceed some limitations of devices used in technical practice.Note that the antenna is the element for realizing a microwave imaging(MWI)system since it is where signal transmission and absorption occur.Ultra-Wideband(UWB)antenna superstrates with MTM elements to ensure the signal transmitted from the antenna reaches the tumor and is absorbed by the same antenna.The lack of conventional head imaging techniques,for instance,Magnetic Resonance Imaging(MRI)and Computerized Tomography(CT)-scan,has been demonstrated in the paper focusing on the point of failure of these techniques for prompt diagnosis and portable systems.Furthermore,the importance ofMWIhas been addressed elaborately to portray its effectiveness and aptness for a primary tumor diagnosis.Other than that,MTM element designs have been discussed thoroughly based on their performances towards the contributions to the better image resolution of MWI with detailed reasonings.This paper proposes the novel design of a Zeroindex Split RingResonator(SRR)MTMelement superstrate with a UWB antenna implemented in MWI systems for detecting tumor.The novel design of the MTM enables the realization of a high gain of a superstrate UWB antenna with the highest gain of 5.70 dB.Besides that,the MTM imitates the conduct of the zeroreflection phase on the resonance frequency,which does not exist.An antenna with an MTM unit is of a 7×4 and 10×5 Zero-index SRR MTM element that acts as a superstrate plane to the antenna.Apart from that,Rogers(RT5880)substrate material is employed to fabricate the designed MTM unit cell,with the following characteristics:0.51mm thickness,the loss tangent of 0.02,as well as the relative permittivity of 2.2,with Computer Simulation Technology(CST)performing the simulation and design.Both MTM unit cells of 7×4 and 10×5 attained 0°with respect to the reflection phase at the 2.70 GHz frequency band.The first design,MTM Antenna Design 1,consists of a 7×4 MTM unit cell that observed a rise of 5.70 dB with a return loss(S11)−20.007 dB at 2.70 GHz frequency.The second design,MTM Antenna Design 2,consists of 10×5 MTM unit cells that recorded a gain of 5.66 dB,having the return loss(S11)−19.734 dB at 2.70 GHz frequency.Comparing these two MTM elements superstrates with the antenna,one can notice that the 7×4 MTM element shape has a low number of the unit cell with high gain and is a better choice than the 10×5 MTM element in realizing MTM element superstrates antenna for MWI.

Study on the Generation of Ultra-Wideband (UWB) High Power Microwave

The experimental study of ultra-wideband (UWB) technology, its generation and on-line measurement are presented. An experimental repetitive UWB system is designed, manufactured, and tested. High-pressure spark gap switch and its components, as well as oil spark gap switch are studied experimentally on the system. Experimental results indicate that the system operates at a 200 pps repetitive rate with a stable performance. 100 MW peak power UWB pulses are obtained on the system. Fast-time response capacitive divider is designed and fabricated, allowing for an accurate measurement of the high power UWB signal. The main issues related to the design of the switch and the UWB signal online measurement are discussed.

Ultra-Wideband RoF System and Its Key Technologies

The microwave photonic technology-based Ultra-Wideband (UWB) Radio over Fiber (RoF) system is an important solution to the future low-cost and high-performance ultra-wideband wireless access network.Much research work has been done in this field with abundant results.This article introduces the RoF system that is based on the all-optical vector modulation technology to further enhance signal’s spectrum efficiency;the full-duplex RoF system that is based on the millimeter wave Phase-Shift Keying (PSK) modulation to greatly simplify base station structure and fiber layout;and the RoF system that is based on multi-service mixed transmission to carry the service with both wired signal and several wireless signals.The article also presents an RoF-based high-definition video transmission platform.

TRULY BALANCED PULSE GENERATOR USING MICROWAVE TRANSISTOR AND SRD

A novel efficient circuit for Ultra-WideBand(UWB) balanced sub-nanosecond monocycle pulse generation is presented.The pulse generator employs wideband bipolar transistor,step recovery diodes,Schottky diodes,and simple charging and discharging circuitry.Simple transient analysis and design of the circuit are presented along with their operating principle.The pulse generator produces truly balanced monocycle pulse with 500 ps pulse-width and 800 mV peak voltage.The generated monocycle pulse also has very symmetrical positive and negative portions and low ringing level.The presented pulse generator can be used as both a transmitter feeding UWB balanced antennas without broadband baluns and a balanced switching pulse generator that used in UWB receiver.

A novel advanced oxidation process to degrade organic pollutants in wastewater:Microwave-activated persulfate oxidation

This article, for the first time, provides a novel advanced oxidation process based on sulfate radical （SO^4·-） to degrade organic pollutants in wastewater： microwave （MW）-activated persulfate oxidation （APO） with or without active carbon （AC）. Azo dye acid Orange 7 （AO7） is used as a model compound to investigate the high reactivity of MW-APO. It is found that AO7 （up to 1000 mg/L） is completely decolorized within 5-7 min under an 800 W MW furnace assisted-APO. In the presence of chloride ion （up to 0.50 mol/L）, the decolorization is still 100% completed, though delayed for about 1-2 min. Experiments are made to examine the enhancement by AC. It is exciting to find that the 100% decolorization of AO7 （500 mg/L） is achieved within 3 min by MW-APO using 1.0 g/L AC as catalyst, while the degradation efficiency maintains at 50% by MW energy without persulfate after about 5 min. Besides the destruction of visible light chromophore band of AO7 （484 nm）, during MW-APO, two bands in the ultraviolet region （228 nm and 310 nm） are rapidly broken down. The removal of COD is about 83%-95% for 500 mg/L AO7. SO^4·- is identified with quenching studies using specific alcohols. Both SO^4·- and ·OH could degrade AO7, but SO^4·- plays the dominant role. In a word, MW-APO AC is a new catalytic combustion technology for destruction of organic contamination even for high concentration.

BP Neural Network Based on Microwave Method for Measuring the Moisture Content of Textile

The moisture content of yarn and fabric is an important factor in textiles industry.A novel microwave method used for material moisture content measurements is described in this paper.It can estimate the moisture content of the yarn roll with a standard deviation of 1.58% in the range of 0% to 90.00%.According to the actual size of the yarn,the yarn roll simulation model is established.The microwave attenuation variations arising from the changes in the conductivity and dielectric constant of the wet cone yarn from1.8 GHz to 5.0 GHz frequency are obtained by ultra-wideband antenna.The measured data are analyzed using the BP neural network.The result shows that it is a non-contact and online method to solve the moisture content of the yarn in the wide moisture content range.

Crystal Structure and Antimicrobial Properties of Rare Earths Aryl-acylhydrazone Complexes under Microwave Irradiation

2-Carbonyl propionic acid-4-methyl benzoyl hydrazone （PAMH） has been synthe-sized by using 4-methyl benzoyl hydrazine and pyruvic acid as the chemicals and acetic acid asphase transfer catalyst under microwave radiation. Then the PAMH and TbCl3·6H20 are placed inthe methanol/acetone/water （3：2：4） mixture for coordination reaction, getting the Schiff complexTb（PAMH）3. The crystal structure is characterized by elemental analysis, X-ray Diffraction （XRD）and infrared spectrum. The compound crystallizes in the monoclinic space group P21/n, with a =1.4770（4）, b = 1.2864（3）, c = 1.9287（5） nm, β= 92.06（3）°, V= 3.6623（15） nm3 and Z= 4. Tb（Ⅲ） ionis nona-coordinated by three completely deprotonated PAMH ligands in a tricapped trigonal prismgeometry, leaving a zero-dimensional mononuclear configuration. The optical properties and thermalstability are studied by ultraviolet spectrum, fluorescence spectra and thermogravimetric analysis（TGA）. The antibacterial activities of the ligand and rare-earth complex are preliminarily studied,and found they have certain antibacterial activity on fusarium solani, and the complex is obviouslymore effective in suppressing fusarium solani than the ligand.

接地共面波导与芯片级联结构设计与优化

针对传输线与芯片级联时产生阻抗突变,导致传输效率下降的问题,基于接地共面波导与芯片级联结构,提出了一种适用于X~Ka波段的匹配带线解决方法。通过S参数提取芯片的输入阻抗,并对射频电路中的阻抗不连续点进行分析,设计阻抗匹配电路并建立三维仿真模型。通过有限元仿真分析,讨论了匹配电路和键合引线中心间距对射频传输性能的影响,对比分析了不同结构及不同匹配电路的传输性能差异。仿真结果显示:在X~Ka波段范围内,匹配电路可令接地共面波导与芯片级联结构的S11<-21 dB,S21>-0.19 dB。优化后的接地共面波导与芯片级联结构可在降低传输损耗的同时显著提高射频信号的隔离度,减少信道串扰,为厘米波频段下射频电路的设计提供理论参考。

基于薄膜铌酸锂的微波光子雷达芯片

微波光子雷达拥有分辨率高、处理速度快、同时多波段、多功能等优势,在航天系统中具有广阔的应用前景。为了满足航天应用对雷达系统体积、质量和功耗的严格要求,集成化已经成为微波光子雷达的重要发展方向。介绍了一款基于薄膜铌酸锂的微波光子雷达芯片,利用该芯片实现了雷达发射信号倍频产生和回波信号去斜接收,并对距离天线不同位置的目标进行了测距实验,得到的测量距离与实际距离基本相同,两者之间的误差小于4 mm。

微波光子信号同步及其在分布式相参雷达中的应用

分布式相参雷达技术通过多节点高性能信号同步实现跨平台的信号级相参融合,可大幅提升雷达探测、跟踪和抗干扰等能力,是雷达领域的重要发展方向之一。随着雷达频率范围的拓展、瞬时带宽的增大和搭载平台的多样化,分布式相参雷达技术对节点间信号的时间、空间、频率、相位同步性能提出了越来越高的要求,这使得传统电学信号同步技术面临巨大挑战。文中介绍了分布式相参雷达对信号时、空、频、相同步的性能要求和国内外相关技术的研究进展,重点总结了微波光子同步技术的基本原理和代表性成果;构建了微波光子分布式相参探测原理验证系统,验证了微波光子分布式相参的可行性,为推动分布式相参雷达的前沿发展与工程化应用提供了关键技术支撑。

响应面优化超声波微波协同提取猕猴桃茎黄酮工艺及抗氧化活性分析

为提高软枣猕猴桃树体资源利用率,以野生软枣猕猴桃茎为实验原料,并使用超声波微波协同提取猕猴桃茎总黄酮,采用Plackett-Burman试验设计,评价影响茎黄酮提取效率的超声功率、超声时间等7个因素,并筛选出其中3个显著影响因素:料液比、超声温度、微波时间.在此基础上,进一步采用Box-Benhnken最陡爬坡路径方法及响应面设计优化出3个显著影响因素的最佳参数水平.结果显示:料液比45 mL/g、超声温度55℃、微波时间5.5 min,此条件作用下,黄酮类化合物提取率可达9.25%.在测定的质量浓度中,软枣猕猴桃茎黄酮对DPPH、羟基的清除能力优于VC,而对超氧阴离子的清除差于VC,但对三种自由基均有一定清除能力.以上结果表明,软枣猕猴桃茎黄酮提取物具有良好的抗氧化活性.

不同生长期云南乌天麻活性成分分析及其微波加工工艺优化

目的 分析不同生长期云南乌天麻活性成分,并优化其微波加工工艺。方法 分别于当年10、11、12月至次年1、2月采集样品,HPLC法测定天麻素、对羟基苯甲醇、巴利森苷A、巴利森苷B、巴利森苷C、巴利森苷E的含量。在单因素试验基础上,以微波时间、微波功率、样品量为影响因素,外观评价及各活性成分总含量为评价指标,正交试验优化微波加工工艺。结果 6种活性成分在各自范围内线性关系良好(R^(2)>0.999 0),平均加样回收率86.76%~104.42%,RSD 3.70%~15.09%。最佳条件为先微波熟化(微波时间2 min,微波功率500 W)再微波干燥(微波时间4 min,微波功率200 W),各活性成分总含量在每1 g样品中的占比达3.98%。结论 11月是乌天麻最佳采摘期,微波熟化结合微波干燥后活性成分总含量最高。

快速响应的NV色心微波传感器实现及测量

高精度微波快速测量技术是电磁频谱分析监测的核心,微波测量技术为微波传感器的高精度测量提供了可能。通过建立NV色心空间磁场能级响应频率精密调谐模型,结合NV色心光学宽场成像技术,实现了高精度、响应快可调的微波测量。首先,通过连续光探测磁共振(ODMR)技术,结合宽场成像技术,通过像素级磁场强度-微波频率转化关系,实现宽场成像的微波测量;进而将连续扫频技术转变为施加定频进行检测,通过同步监测频点不同的响应特性,验证了测试结果的有效性。以上结果为高精度固态量子频谱分析仪、高瞬时带宽频谱微波传感器提供了重要技术基础。

频域宽带阵列波束形成技术优化设计

为提高宽带相控阵系统的波束合成性能,文章针对宽带相控阵系统中的延时补偿问题,采用频域宽带阵列波束形成的方法,分析了宽带相控阵中应用交叠FFT进行时延补偿的原理和误差造成的原因;基于一个接收信号带宽为600 MHz的64阵元的宽带相控阵系统,研究了子阵规模、FFT点数、交叠率、位宽、采样率等交叠FFT参数对延时精度、信号保真度和波束性能的影响,在满足工程应用要求的同时对频域宽带阵列波束合成技术进行了优化;经研究确定子阵规模不超过9个天线阵元、FFT点数不小于512、交叠率不小于1/16、位宽不小于采用12 bit时可以达到指标的要求,为交叠FFT方法应用在实际工程中提供了依据与参考,并使其工程实现复杂度降低。

基于微波光子的复合式时频传输技术研究

光载射频传输技术在地基无源探测、分布式阵列合成孔径、空间探测等诸多领域具有广泛的应用,用于实现不同子阵之间的信号互连与信号相参。针对传统光载射频传输技术中相位稳定度低、时延变化大、易受环境影响等问题,本文提出一种复合式微波光子时频传输技术,通过结合被动和主动时频传输技术,分别实现了本振点频信号的光纤分发和中频宽带信号的光纤回传,联合两者之间技术优势实现了系统的相位高稳定度和宽带信号传输的目的。本系统可实现本振信号、中频信号在中心端和远端的时频稳相传输。通过对比实验和综合测试,实现1.6 GHz本振和(1.6±0.5)GHz中频信号的稳相传输,传输距离为5 km,经过在-40~+70℃的环境试验验证,温度变化范围内上下行微波光子链路中相位波动小于±1.5°。

微波加热技术在页岩气开采中的应用研究综述

近年来,随着全球能源需求不断增长,页岩气作为一种新兴油气资源在全世界范围内掀起了勘探开发热潮。页岩气传统开采方式受限于气体赋存状态和储层复杂特性难以被高效开采,因此寻求一种新型开采方式对页岩气开发具有重要的现实意义。微波加热作为一种高效、环保且可控的新型热采技术,展现出巨大的潜力和广泛的应用前景,有望成为页岩气开发中常规热采方法的理想替代。总结分析页岩气开采技术种类,对比突出微波加热技术在页岩气开采领域的发展潜力;概括微波加热的物理原理和作用机理,综述微波加热提高页岩气采收率的相关数值模拟和实验研究,阐述微波加热影响页岩气采收率的作用机理,总结微波特性(如频率、功率、加热方式)和矿物物性(如介电常数、含水率)对页岩气采收率的影响,讨论现有研究的不足进行,提出未来大规模应用微波加热方法的展望。为充分发挥微波加热技术的发展潜力,该技术需要进一步深化理论和实验研究,将尺度升级至矿场实验,全方位验证微波加热在实际储层条件下的可行性和适用性。

大中型粮食烘干设备研究进展

随着农业科技的进步,粮食烘干设备在粮食加工过程中得到广泛应用。而关于粮食烘干的研究大多集中在工艺优化上,对于粮食烘干设备的研究较少,导致新型工艺技术难以应用,粮食烘干设备的进步受到制约。目前应用于粮食烘干的有热风、热泵、远红外、太阳能、真空、微波以及联合干燥设备,本文从工作原理、干燥效率、干后品质、能源消耗、发展趋势等方面对以上粮食干燥技术及其设备进行综述,介绍了节能环保、智能调控的新型干燥设备的研究现状,分析了各种大中型粮食烘干设备及技术存在的问题,并对粮食烘干设备的发展趋势提出建议,以期为粮食烘干产业健康发展提供参考。