Radar cross section (RCS) reduction in the working band of antennas, likely leading to radiation performance change or deterioration, is quite difficult for both antenna elements and arrays. Aimed at this problem, article presents a novel design strategy microstrip patch antennas with low in-band RCS. This combines metasurface from perspectives structure electrical performance. To be specific, anisotropic proposed replace conventional behave as radiating directly, which does not increase...

The reversible color change of the silole-infiltrated SiO2 inverse opal photonic crystal (IOPC) film can be obtained by alternating its exposure to different vapor environments. When was put in diethyl ether or petroleum vapor, a stopband red shift more than 100 nm could clearly observed, while changed from green red. exposed air, underwent blue and back green. result is attributed silole molecules, hexaphenylsilole (HPS), which transformed reversibly between amorphous state when alternately...

Monitoring variations in terrestrial water storage (TWS) is of great significance for the management resources. However, it remains a challenge to continuously monitor TWS using situ observations and hydrological models because limited number gauge stations complicated spatial distribution characteristics TWS. In contrast, Gravity Recovery Climate Experiment (GRACE) could overcome aforementioned restrictions, providing new reliable means observing variation. Thus, GRACE was employed...

ABSTRACT Drought is considered a major contributor to carbon sink fluctuations in terrestrial ecosystems and expected lead more frequent sink–source transitions under future climate change. The drought threshold for transition reflects the critical inflection point at which sequestration capacity of vegetation affected by water deficit. However, spatiotemporal patterns global their underlying mechanisms remain poorly understood. Here, we use three independent datasets from dynamics models,...

Abstract In recent years, the accelerated development of astronomy has created an urgent need for spectroscopic survey instruments with high speed and efficiency. The 6.5 m Wide Field Multiplexed Survey Telescope (MUST) proposed by Tsinghua University aims to address this need. paper, we present medium spectral resolution multi-object fiber-fed spectrograph meet science requirement MUST project. spectrograph, utilizing 92 mm × large-size detectors, can accommodate 750 fibers a core diameter...

Abstract X‐ray photography plays an important role in the fields of medical treatment, security inspection, and non‐destructive testing. The high image quality depends on detectors with excellent properties. To meet future demand for high‐performance scintillation screens, adding a new luminescent center Cs 3 Cu 2 I 5 by doping is considered. successful incorporation Mn brought luminescence peak at 565 nm. Different excitation modalities such as ultraviolet X‐rays have ability to tune...

The lattice, the band gap and optical properties of n-type ZnO under uniaxial stress are investigated by first-principles calculations. results show that lattice constants change linearly with stress. Band gaps broadened as compressive increases. for comes mainly from contribution in c-axis direction, reason changing is also explained. calculated reveal imaginary part dielectric function decreases increase at low energy. However, when energy higher than 4.0 eV, increases a blueshift appears....

We describe a microelectromechanical systems-based actuator for three-dimensional (3D) positioning of polymer microlens implemented using silicon-on-glass technology. The combines comb drives lateral tracking with electrostatic parallel plates out-of-plane focusing as well tilting microlens, yielding fully 3D actuation. complete is fabricated wafer bonding silicon and pyrex wafers; the lens integrated dispensing techniques. 3 DOF focusing, tracking, are experimentally characterized,...

The residual low-angle grain boundary (GB) network is still the most important current-limiting mechanism operating in biaxially textured rare-earth barium-copper-oxide (REBCO) coated conductors. While Ca doping well established to improve supercurrent flow across GBs weak fields at high temperatures, also depresses ${T}_{c}$, making it so far impractical for high-temperature applications of REBCO On other hand, high-field-magnet require low temperatures. Here we systematically evaluate...

This paper introduces the design of a feed subsystem for multiple-beam array-fed reflector antenna. The prototype is composed 37 circularly polarized horns and complicated RF switch matrix. are divided into four interleaved groups. Each time adjacent horns, i.e., each from one group, selected by matrix to connect signal processor where delivered signals weighted combined form radiation beam. beam can be controlled hop in certain zone with response at level μs. use reduces cost processing. By...

A radio-over-fiber(ROF) downlink system based on a new polarization-stable millimeter-wave generator is proposed to reduce costs, increase transmission distance and improve performance. Compared with traditional system, the uses two laser signals produced by selecting frequency of polarization maintaining fiber Bragg grating(PMFBG) generate beating frequency. It easy be implemented influence power noise reduced. The effects power, linewidth reflectance spectrum PMFBG performance are...

In recent decades, rapid advances in astronomical imaging campaigns have generated an urgent need for detailed spectroscopic surveys with increased speed and efficiency. The 6.5 m MUltiplexed Survey Telescope (MUST) aims to address these current demands. performance of the multi-object fiber-fed spectrograph (MOFS) plays a critical role survey telescopes, directly influencing realization scientific aims. this paper, we demonstrate high-resolution highly-multiplexed option MOFS MUST. system...

Shack-Hartmann (SH) wavefront sensing is widely applied to astronomical observations with its fast and accurate measurement. However, due the computational nature of SH that input beam segmented provide local slopes, sampling density sub-apertures calculation accuracy each sub-focal spot’s centroid have great influence on reconstruction accuracy. Therefore, it usually difficult achieve high resolution for dark stars in insufficient light intensity. We present a neural-network assisted method...

A special feeding network is designed with a 3dB quadrate bridge and two baluns, which works at s-band (2~2.3GHz) to achieve the dual-circular polarization. Because of its structure, has advantages single-caliber, low profile cost. Simulation results show that presents good properties during required frequency range, meets engineering requirement very well.

Significant advances in the technical capabilities of microlens actuators for optical pickups have been achieved using MEMS technology, enabling miniaturization and integration data storage systems. In this work, a new type compact silicon-on-glass (SOG) actuator two-dimensional (2-D) positioning dispensed polymer is developed by technology. A wafer-level process fabrication SOG anodic bonding pyrex wafer an ultra-thin silicon wafer. Dispensed microlenses are subsequently integrated onto 2-D...

For the underpass railway large-section box culvert jacking and pipe project, key to ensuring normal operation of existing is maintain smoothness stability track, settlement monitoring line reinforcement, attitude control are keys solving this problem. Taking Beijing-Harbin high-speed project under a city road in Beijing as an example, law track during implementation was analyzed according real-time data. The results show that accelerating pouring bedding grouting strengthening subgrade on...