4039wileyonlinelibrary.com mole cules and depends highly on the analyte concentrations. [8][9][10][11][12] As a result, the traditional Ohm-contacted nanosensor has diffi culty in realizing the ultrasensitive detection in real circumstances where open environment must be considered. Recently, it was demonstrated that Schottky contact could largely improve the sensitivity of nanosensors due to that Schottky barrier serves as a "gate" controlling the current passing through the barrier, [ 13,14 ] and the value of this current highly depends on the Schottky barrier height (SBH). A small change in SBH will lead to a huge change in current, which is the basis of the Schottky barrier enhanced sensing. [ 13 ] The selection of the components of the Schottky junction is of vital importance to improve the sensor performance, which highly depends on the energy band structure and adsorption characteristics. It is reported that a higher SBH favors a better sensitivity in a Schottky-gated sensor toward electron acceptor analytes detection, while for electron donor analytes detection, the result is opposite. [ 15 ] Thus, the insertion of another semiconductor that could both modulate the SBH and increase the adsorption energy will greatly increase the sensitivity and selectivity in a Schottky junction sensor. Graphene or reduced graphene oxide (rGO) with high charge carrier mobility, atomically thin nature and abundant adsorption sites, [16][17][18][19][20] makes the semiconductor/graphene Schottky heterojunction (Barristor) ultrasensitive for gas sensing. [ 21,22 ] Vertical silicon nanowires (SiNWs) array offers distinct merits in terms of the capability for surface functionalization and the suffi cient gaps for molecules diffusion, and SiNWs array-based sensor has been considered an ideal platform for gas sensing due to the higher signal-to-noise ratios and faster response. [ 23,24 ] The electron affi nity of TiO 2 (4.0 eV) is only a bit smaller than that of silicon (4.05 eV); [ 25 ] thus the insertion of TiO 2 into Si/rGO should be an ideal choice to support the above assertion. As a result, the SiNWs array/TiO 2 /rGO ternary junction will provide a new approach for designing ultrasensitive and selective sensors.Nitro-explosives is one of the most important categories in common explosives, and the detection of them has been a research focus due to plenty of adverse events, increasing threat of terrorism attack, and the need for homeland security. [ 1,9,26,27 ] The sensitive, selective, and rapid detection of nitro-explosives vapors is still a challenge due to the low vapor pressure of

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A frequency selective rasorber (FSR) with three transmission bands and three absorption bands is proposed in this paper. The FSR is constructed via cascading a lossy resistive surface and a multiple bandstop frequency selective surface (FSS) separated by air spacer. The transmission characteristics are obtained by the impedance poles of the interdigital capacitor-meander inductor resonators in the resistive surface and also the rectangular loop resonators in the FSS. The absorption bands are achieved using the ohmic loss of the resistors in the resistive surface along with the reflections of the FSS. The physical principle of operation of the multiband FSR is explained based on an equivalent circuit model. A prototype is fabricated and measured. The experimental results exhibit three transmission bands at 6.1 GHz, 8 GHz and 10 GHz with insertion loss below 0.9 dB, 0.8 dB and 0.8 dB, respectively. The effective absorption bands are in range of 7.05 GHz-7.55 GHz, 8.87-9.35 GHz and 12.59 GHz-14.22 GHz, respectively. The simulation results show the angular stability of the FSR response. In addition, the effect of FSR dimensions on the transmission/absorption bands is studied. INDEX TERMS Frequency selective rasorber, triple-band transmission, triple-band absorption, interdigitalcapacitor/meander-inductor resonator.

Intricate superstructures possess unusual structural features and promising applications. The preparation of superstructures with single-crystalline nature are conducive to understanding the structure-property relationship, however, remains an intriguing challenge. Herein we put forward a new hierarchical assembly strategy towards rational and precise construction of intricate single-crystal superstructures. Firstly, two unprecedented superclusters in Rubik's cube's form with a size of � 2 × 2 × 2 nm 3 are constructed by aggregation of eight {Pr 4 Sb 12 } oxohalide clusters as secondary building units (SBUs). Then, the Rubik's cubes further act as isolable tertiary building units (TBUs) to assemble diversified single-crystal superstructures. Importantly, intermediate assembly states are captured, which helps illustrate the evolution of TBU-based superstructures and thus provides a profound understanding of the assembly process of superstructures at the atomic level.

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A novel Energy Selective Filter (ESF) mounted in waveguide is presented based on nonlinear element, which is sensitive to the power intensity of incident wave achieving frequency selection as well as energy selection. The proposed ESF consists of three parts, the middle circuit board with diode loaded, the upper and bottom ground metallic patches. The mechanism of the ESF is analyzed through equivalent circuit model and its performance is investigated numerically and experimentally. According to the waveguide measurement, a shielding effectiveness of 13 dB is achieved in case of high power input and the insertions loss is less than 0.3 dB across the whole frequency range when low power signal inputs. It is a pluggable component in waveguide that could reflect high power signals of specific frequency to protect the following electronic equipment.

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