Split-Ring Structured All-Inorganic Perovskite Photodetector Arrays for Masterly Internet of Things

Photodetectors with long detection distances and fast response are important media in constructing a non-contact human-machine interface for the Masterly Internet of Things(MIT).All-inorganic perovskites have excellent optoelectronic performance with high moisture and oxygen resistance,making them one of the promising candidates for high-performance photodetectors,but a simple,low-cost and reliable fabrication technology is urgently needed.Here,a dual-function laser etching method is developed to complete both the lyophilic split-ring structure and electrode patterning.This novel split-ring structure can capture the perovskite precursor droplet efficiently and achieve the uniform and compact deposition of CsPbBr3 films.Furthermore,our devices based on laterally conducting split-ring structured photodetectors possess outstanding performance,including the maximum responsivity of 1.44×105 mA W^(−1),a response time of 150μs in 1.5 kHz and one-unit area<4×10-2 mm2.Based on these split-ring photodetector arrays,we realized three-dimensional gesture detection with up to 100 mm distance detection and up to 600 mm s^(−1) speed detection,for low-cost,integrative,and non-contact human-machine interfaces.Finally,we applied this MIT to wearable and flexible digital gesture recognition watch panel,safe and comfortable central controller integrated on the car screen,and remote control of the robot,demonstrating the broad potential applications.

Residual stress in the cylindrical drawing cup of SUS304 stainless steel evaluated by split-ring test

The residual stresses in the wall of a SUS304 stainless steel cylindrical drawing cup were evaluated by split-ring tests, and the influences of stamping die parame- ters on the residual stress were investigated. A new theoretical model of a split-ring test was developed to evaluate the resid- ual stress in a ring, which was verified to be reasonable and reliable by numerical simulations with ABAQUS code and by nanoindentation tests. Seven groups of split-ring tests were completed, and the residual stresses were calculated according to the theoretical model. The split-ring test results showed that the circumferential residual stress in the wall of the SUS304 stainless steel cylindrical drawing cup was very large and did not change with the different die comer radius. The circumferential residual stress first increased with the increase of drawing punch-die clearance, then was almost unchanged when the clearance increased greater than blank thickness 1 mm. Thus, a smaller clearance was suggested to be chosen to reduce the residual stress in the wall of the SUS304 stainless steel drawing cup.

Band-stop optical nanofilters with split-ring resonators based on metal–insulator–metal structure

Novel band-stop filters with circular split-ring resonators based on the metal-insulator-metal （MIM） structure are presented, with their transmission properties of SPPs propagating through the filter simulated by the finite-difference time-domain （FDTD） method, The variation of the gap of the split ring can affect the transmission characteristics, i.e., the transmission spectrum of SPPs exhibiting a shift, which is useful for modulating the filter. Linear and nonlinear media are used in the resonator respectively. By varying the refractive index of the linear medium, the transmission properties can be changed obviously, and the effect caused by changing the incident intensity with a nonlinear medium is similar. Several resonant modes that are applicable can be enhanced by changing the position of the gap of the split ring. Thus, the transmission properties can be modulated by adjusting the size of the gap, varying the refractive index, and changing the incident intensity of the input light. These methods may play significant roles in applications of optical integrated circuits and nanostructural devices.

Design of Multi-band Small Antenna Based on Single Split-Ring Resonator

To use the single split-ring resonator （SRR） as a basic unit cell for small antenna with multi-band frequency response is proposed. The structure of antenna is consisted of a single spilt-ring resonator and a coupled microstrip line. The designed antenna is numerically optimized with CST Microwave Studio. The radiation properties of the antenna show that there are three frequency bands among which two bands are 1.3 GHz and 2.1 GHz ultra-widehand （UWB）, respectively, where Sll is less than - 10 dB. The gain at every frequency for the multi-hand antenna is above 2.6 dBi, and it increases monotonously with the frequency in the two UWB.

Effects of oblique incidence on terahertz responses of planar split-ring resonators

Effects of oblique incidence of terahertz waves on the response of planar split-ring resonators are investigated, both experimentally and by simulation. It is found that the incident angle dependent phase delay and coupling conditions of neighboring split-ring resonator （SRR） units play important roles and greatly change both the transmission and reflection spectra for the resonant feature of linear charge oscillations. Our results show that the SRR structure-supported magne- toelectric couplings at oblique excitation are trivial and can be ignored. A highly symmetric response is found in the cross-polarization effects, which may manifest the bianisotropic properties of the SRR system but this needs further study.

Expanding the bandwidth of planar MNG materials with co-directional split-ring resonators

An effective approach to expand the bandwidth of negative permeability of small-sized planax materials is proposed. Based on qualitative analysis of equivalent circuit models, the fractional bandwidth of an μ-negative （MNG） material is expanded from 3.53% up to 12.87% by adding split-ring resonators （SRRs） and arranging them by proposed steps. Moreover, the experimental results validate the effectiveness of bandwidth-expanding methods, which is promising for the extensive application of metamaterials in the microwave field.

Experimental Study on Split-Ring Resonators with Different Slit Widths

Metamaterial one-dimensional periodic structures are composed of split-ring resonators, which can display electric permittivity and magnetic permeability simultaneously negative, are studied experimentally. In the present study, each resonator is made up of two concentric circular copper rings patterned on a substrate of kapton, with slits diametrically opposite each other and with the line of the splits along the longitudinal direction of the periodic array containing seven split rings evenly spaced. The experiments consist in inserting the metamaterial slab into a square waveguide of side length 6 mm, corresponding to a cutoff frequency of 25 GHz. Transmission bands due to magnetic and electrical responses are identified for slits with aperture widths of 1 mm and 2 mm, centered at 5.67 and 6.12 GHz frequencies, respectively, values well below the 25 GHz frequency cutoff, so characterizing a medium with negative permeability and permittivity.

Tunable multiband terahertz metamaterials using a reconfigurable electric split-ring resonator array

We demonstrate micromachined reconfigurable metamaterials working at multiple frequencies simultaneously in the terahertz range.The proposed metamaterial structures can be structurally reconfigured by employing flexible microelectromechanical system-based cantilevers in the resonators,which are designed to deform out of plane under an external stimulus.The proposed metamaterial structures provide not only multiband resonance frequency operation but also polarization-dependent tunability.Three kinds of metamaterials are investigated as electric split-ring resonator(eSRR)arrays with different positions of the split.By moving the position of the split away from the resonator’s center,the eSRR exhibits anisotropy,with the dipole resonance splitting into two resonances.The dipole–dipole coupling strength can be continuously adjusted,which enables the electromagnetic response to be tailored by adjusting the direct current(DC)voltage between the released cantilevers and the silicon substrate.The observed tunability of the eSRRs is found to be dependent on the polarization of the incident terahertz wave.This polarization-dependent tunability is demonstrated by both experimental measurements and electromagnetic simulations.

Continuous Tera-Hertz wave transmission spectroscopy of Nb double superconducting split-ring resonator array

Transmission spectroscopy of two Nb double superconducting split-ring samples with different thicknesses on MgO substrates was measured by a continuous Tera-Hertz spectrometer.The transmission curves of two different samples with the thicknesses of 50 and 150 nm at 7.5 K show dips at 480,545 GHz,respectively,which origin from the different capacities and inductances of the samples.For the sample of 50 nm,the dip shifts to lower frequency,also decreases in depth and increases in width with temperature or field increasing below T c of Nb film,while the sample of 150 nm does not show such a phenomenon.This thickness-dependent transmission behavior is due to the kinetic inductance and conductivity change of superfluid electrons in Nb film and may suggest a practical tunable THz filter based on the thinner samples.

Terahertz radiation enhancement in photoconductive antennas with embedded split-ring resonators

This Letter proposes a novel method for enhancing terahertz(THz) radiation from microstructure photoconductive antennas(MSPCA). We present two types of MSPCA, which contain split-ring resonators(SRRs) and dipole photoconductive antennas(D-PCAs). The experimental results reveal that when the femtosecond laser is pumping onto the split position of the SRR, the maximum THz radiation power is enhanced by 92 times compared to pumping at the electrode edge of the D-PCA. Two π phase shifts occur as the pumping laser propagates from the negative electrode to the positive electrode. Analysis shows that photoinduced carrier charges move within the split position of the SRR.

Broadband coplane metamaterial filter based on two nested split-ring-resonators

Split ring resonators （SRRs）-based broadband metamaterial filters have attracted considerable attention due to their great prospect of practical applications. These filters had been usually obtained by stacking multiple different-sized metallic patterns, making their fabrication quite troublesome. Herein, we presented a simple design of broadband filter composed of two nested SRRs. The resonance bandwidth of the metamatefial filter gradually increased with the decrease of the ann length of the inner SRR. The increase in the resonance bandwidth was attributed to the increase in the radiation of the entire structure. Moreover, the bandwidth of the metamaterial can be further broadened by decreasing the period of the structure. The proposed filter provides a meaningful way toward expanding the bandwidth operating range from narrowband to broadband in an effective way.

基于慢波基片集成波导的小型化移相功分器

针对移相器和功分器的功能融合设计,提出了一种基于慢波基片集成波导(Slow-Wave Substrate Integrated Waveguide,SW-SIW)的小型化移相功分器,两个输出分支等长带宽,可实现30°相移量.其中一个输出分支通过基片集成波导(Substrate Integrated Waveguide,SIW)实现,而另一个输出分支将互补开口谐振环(Complementary SplitRing Resonator,CSRR)加载在上层金属表面,代替传统SIW连续的金属表面,该CSRR由经典CSRR结构演变而来,同时为了降低由CSRR加载所造成的相位上的不稳定,在CSRR内部添加金属化通孔,实现SW-SIW,使得截止频率和相速度降低.测试结果表明,移相功分器在9.0~11.8 GHz频带范围内反射系数|S11|小于-10 d B,相对工作带宽为26.9%,插入损耗小于1.3 d B.两个输出端口的相位差稳定在30°±3°,幅度差小于1.4 d B,实现了等功率分配.所设计的移相功分器具有较小的尺寸和低制造成本,适合应用在相控阵天线中.

无芯片RFID高温传感器设计

设计了一种用于高温环境实时监测的基于开口环谐振器(SRR)的无芯片射频识别(RFID)传感器。传感器由双开口圆环谐振结构和氧化铝(Al_(2)O_(3))陶瓷基板构成,尺寸为25 mm×25 mm×0.5 mm。其工作原理是:Al_(2)O_(3)陶瓷基板作为温度敏感材料,具有耐高温的特性,而且介电常数随温度变化而改变,使得整只传感器谐振频率偏移,建立起温度与谐振频率之间的关系,实时监测谐振频率即可获知实时温度。仿真结果表明:设计的温度传感器可以实现200~1000℃监测,对应谐振频率从6.64 GHz下降至6.26 GHz,偏移380 MHz,传感器灵敏度0.475 MHz/℃表现很好,证明了传感器的谐振频率和温度之间存在着准线性关系。设计的无芯片RFID传感器具有无线无源、制作成本低和尺寸小等优点,非常适合应用于高温环境温度检测。

用于测量材料介电常数的高精度微波传感器

提出了一种用于测量材料介电常数的微波传感器,其特点是成本低、测量精度高。在传统的互补裂环结构上进行优化设计,实现了更大范围的测量区域;并加载了金属通孔结构,将电场限制在测量区域内,达到了更好的测量效果。结果显示传感器的测量灵敏度为2.89%。传感器在空载时谐振频率为2GHz;当样品加载到测量区域时,测量区域的电场将发生变化,从而导致频移。选取了介电常数值为1~10的样品进行了模拟加载试验,得到了介电常数与谐振频率的拟合经验关系式,同时采用5种常见的高频板材对拟合公式进行了验证。结果表明:传感器具有很高的测量精度,整体测量误差为0.8%,证实了利用该传感器测量材料介电常数的可行性。

力载荷下分瓣式碳环密封结构变形研究

为探究力载荷下分瓣式碳环密封结构参数对密封面径向变形的影响规律,采用数值计算求解压力控制雷诺方程,获得气膜压力,再结合有限元分析软件进行流固热耦合仿真模拟,探究特定工况下不同结构参数对碳环变形的影响,分析主密封面径向变形特性。研究表明:力变形中,防转销的安装位置对碳环径向变形量影响最大,选取恰当的安装位置可减小径向变形量;外部凸结构不均匀且圆心角比例较大时,径向变形量较小;两侧搭接口比例越大时径向变形量越小;拉紧弹簧和压紧弹簧的选取对碳环径向变形量影响较小;弹簧压力越大时径向变形量越小,但弹簧压力过大时,容易导致碳环磨损加剧、断裂甚至密封失效,应参考实际工况选择适当弹簧压力。研究结果为分瓣式碳环密封的结构优化设计提供参考。

基于分裂型弯铁的储存环超周期HMBA磁聚焦结构

提出了1种使用分裂型弯铁(split-bend)实现的储存环超周期混合型多弯铁消色散(hybrid multi-bend achromat,HMBA)磁聚焦结构(lattice),该结构具有高低β函数值的2种直线节。直线节处较低的β函数值可以提高插入件的辐射亮度,降低插入件对光学函数的影响,而较高的β函数值则可以增大动力学孔径,有利于束流注入。该HMBA lattice使用分裂型弯铁与四极磁铁doublet结构结合形成类triplet结构,在实现高低β函数值直线节的同时,还降低了束流发射度。根据HMBA lattice结构设计了1台能量为3 GeV的衍射极限储存环光源,其自然发射度为101 pm·rad,高β函数值直线节中点处的6D水平动力学孔径约为-8~9 mm,低β函数值直线节中点处的水平与垂直β函数值均小于3.1 m。

基于缺陷地和开口谐振环的三频段小型化天线

提出了一种新型三频段工作的小型微带贴片天线,天线采用不对称结构,在接地板上引入缺陷地结构(DGS)改变了天线表面电流分布,改善工作频率,衍生在无线局域网(WLAN)(2.4 GHz)处的频带。加载开口谐振环(SRR)金属环结构在独立控制WLAN(5.8 GHz)的频带的同时,减小了12%的天线体积。天线结构紧凑,整体尺寸为12.5 mm×28.5 mm×1.5 mm。结果表明,天线覆盖3个独立的阻抗带宽,分别为800 MHz(1.96~2.76 GHz),200 MHz(5.65~5.85 GHz)和1 460 MHz(7.64~9.1 GHz),在频段内的回波损耗均小于-10 dB,具有良好的方向性和增益,支持WLAN(5.8/2.4 GHz)频段和国际电信联盟(ITU)(8.0~8.7 GHz)频段的应用。

维生素E合成路线研究进展

维生素E是一种脂溶性维生素化合物,具有美容养颜、预防衰老、抗不育、抗氧化和抗癌等多种活性,因此对维生素E合成路线的进行探究是制药工作者关注的热点。维生素E是一种天然化学物质,具有生育酚和三烯酚两种结构,每种结构包括α、β、γ及δ4种构型,其中α-生育酚活性最高,效果最好。由于维生素E在医药领域应用范围广、市场需求量大,天然维生素E的产量无法满足临床需求。为进一步扩大维生素E的产能,研究人员发展了系列维生素E的全合成方法。本文总结了已报道的维生素E全合成路线,重点从侧链和主环两个方面进行阐述,旨在为维生素E的合成工艺改进提供参考。

基于超材料的太赫兹波辐射特性与增强研究

太赫兹波的产生与调控对太赫兹技术发展至关重要。超材料的可设计几何结构与特异共振响应为产生与调控太赫兹波提供了新的途径。但超材料产生太赫兹波辐射的转换效率较低仍然是一个亟待解决的问题。设计了一种由金属谐振环阵列和全介质硅开口谐振器组成的超材料。利用麦克斯韦方程联合表述电子运动的流体动力模型的自洽方程组,研究了该超材料的太赫兹波辐射与调控过程。研究发现,通过优化分裂谐振环的开口方向,超材料产生的太赫兹波振幅提高了1倍。此外,通过改变入射光偏振角及超材料的几何尺寸实现了太赫兹波振幅调控。这为基于超材料的,紧凑型和可调谐的太赫兹源提供了新途径。

周期变半径薄圆环模态实验研究

针对变半径法向等厚薄圆环的面内振动模态问题,依据振动测试理论,提出了定测量点、变激振点的实验方法,以简化实验操作流程。利用激光多普勒测振仪和LMS振动测试系统进行测振实验,得到了变半径圆环前八阶振动的固有频率和振型,并将结果与有限元仿真及现有文献相关结论对比,验证了实验方法的可行性。归纳了半径变化周期p和模态阶数n不同关系时结构固有频率的分裂规律,并总结了法向厚度h和半径变化幅度Δ对圆环固有频率的影响。