Complementary bilayer metasurfaces for enhanced terahertz wave amplitude andphase manipulation

Manipulation of terahertz wave by metasurfaces has shown tremendous potential in developing compact and functional terahertz optical devices.Here,we propose complementary bilayer metasurfaces for enhanced terahertz wave amplitude and phase manipulation.The metasurfaces are composed of one layer of metal cut-wire arrays and one layer of their complementary aperture arrays separated by a dielectric spacer.Through the near-field coupling between transverse magnetic resonances in the metal apertures and electric resonances in the metal cut-wires,the structures can manipulate the cross polarization conversion and phase dispersion of terahertz wave.Particularly,the designed metasurfaces demonstrate a phase delay of 180°between two orthogonal axes with the same transmission amplitude between 0.70 and 1.0 THz,enabling a 45°broadband polarization conversion.When the metal cut-wires are rotated with respect to the apertures or the thickness of the dielectric spacer is changed,the amplitude and phase dispersion of the transmitted terahertz wave can be tuned.Such complementary coupled bilayer metasurfaces offer a new method to control the amplitude and phase dispersion of terahertz wave and promise great potential for applications in terahertz meta-devices.

An estimation framework of regional rooftop photovoltaic potential based on satellite remote sensing images

This paper proposes a comprehensive framework for estimating the regional rooftop photovoltaic(PV)potential.The required rooftop information is extracted from Gao Fen-7 satellite images.In particular,the rooftop area is obtained using a semantic segmentation network.The azimuth and inclination angles are calculated based on the digital surface model.In addition,to improve the accuracy of the economic evaluation,buildings are divided into commercial and industrial buildings and residential buildings.Based on the difference in the roof inclination,the rooftops can be divided into flat roofs,on which the PV panels are installed with the optimal inclination angle,and sloped rooftops,on which the PV panels are installed in a lay-flat manner.The solar irradiation on the plane-of-array is calculated using the isotropic sky translocation model.Then,the available installed capacity and generation potential of the rooftop PV is obtained.Finally,the net present value,dynamic payback period,and internal rate of return are used to evaluate the economic efficiency of the rooftop PV project.The proposed framework is applied in the Da Xing district of Beijing,China,with a total area of 546.84 km^(2).The results show that the rooftop area and available installed capacity of PV are 25.63 km^(2)and 1487.45 MWp,respectively.The annual rooftop PV generation potential is 2832.23 GWh,with significant economic returns.

Suppression of ETI by PTI priming to balance plant growth and defense through an MPK3/MPK6-WRKYs-PP2Cs module

Pattern-triggered immunity(PTI)and effector-triggered immunity(ETI)are required for host defense against pathogens.Although PTI and ETI are intimately connected,the underlying molecular mechanisms remain elusive.In this study,we demonstrate that flg22 priming attenuates Pseudomonas syringae pv.tomato DC3000(Pst)AvrRpt2-induced hypersensitive cell death,resistance,and biomass reduction in Arabidopsis.Mitogen-activated protein kinases(MAPKs)are key signaling regulators of PTI and ETI.The absence of MPK3 and MPK6 significantly reduces pre-PTI-mediated ETI suppression(PES).We found that MPK3/MPK6 interact with and phosphorylate the downstream transcription factor WRKY18,which regulates the expression of AP2C1 and PP2C5,two genes encoding protein phosphatases.Furthermore,we observed that the PTI-suppressed ETI-triggered cell death,MAPK activation,and growth retardation are significantly attenuated in wrky18/40/60 and ap2c1 pp2c5 mutants.Taken together,our results suggest that the MPK3/MPK6-WRKYs-PP2Cs module underlies PES and is essential for the maintenance of plant fitness during ETI.

Crystallization and preliminary X-ray analysis of an anti-insect toxin BmK 16 from Buthus martensii Karsch scorpion

An excitatory anti-insect toxin from BmK scorpion, named BmK 16, has been purified and crystallized recently. Two crystal forms have been obtained by using ammonium sulfate as precipitant at different pH, one of which is single crystal. Diffraction data have been collected for the single crystal on a Mar Research 345 Image Plate. The analyses of the data show that the crystal can diffract to 0.28 nm resolution and belongs to the space group C2 with unit cell parameters a = 4.65 nm, b = 8.52 nm, c= 3.26 nm, α= γ= 90oooooooo, β= 110.5°. There are 2 molecules per asymmetric unit according to its unit cell volume and molecular weight.

Crystallization and preliminary crystallographic analyses of human insulin mutant B9(Ser→Asp)in different aggregation forms

B9(Ser→Asp) insulin, one of the fast-acting insulin mutants produced by protein engineering, has been crystallized. Three crystal forms have been obtained, which belong to orthorhombic, tetragonal and rhombohedral system, respectively. Each crystal form contains different aggregation units of the mutant, i.e. dimer or hexamer. The diffraction data of the former two have been collected beyond 0.2 nm resolution. The structural analyses and comparisons will provide some information about insulin’s self-association and the structural basis of the fast absorption produced from the mutation.

Empowering magnetic strong coupling and its application for nonlinear refractive index sensing

In the context of quantum strong coupling,the magnetic dipole(MD)emitters are largely overlooked due to the rarity of MD source and the non-magnetic nature of matters at high frequencies.Based on a semi-classic model,we theoretically demonstrate magnetic strong coupling between an MD cluster(Er^(3+):4 I13/2→4 I15/2 transition at 1,550 nm)and an antenna-in-cavity structure.It is found that placing the plasmonic diabolo/s-diabolo nanoantenna,which supports strong electric/magnetic dipole mode,inside a dielectric cavity could largely improve the strong coupling coefficient while suppressing the cavity loss rate compared to the bare nanoantenna counterparts,empowering the magnetic quantum strong coupling at a level of 104 emitters,which is remarkable considering the weak MD dipole momentum and small hotspot region at high frequency.Furthermore,the two Rabi resonance branches undergo highly asymmetrical changes upon a small variation on the environmental refractive index,which leads to an exotic exponential sensitivity profile by tracing the ratio between the two resonances widths.The proposed magnetic strong coupling for nonlinear refractive index sensing may add a new category to quantum plasmonic sensors.

Middle Triassic(Anisian)Conodont Biostratigraphy at the Shaiwa Section,Guizhou,South China

The Nanpanjiang Basin is a key area for paleontological and biostratigraphical study of the Middle Triassic.Herein we studied Middle Triassic conodonts from a well-exposed section,the Shaiwa Section,which is located at the northwest end of the Nanpanjiang Basin.A total of six Anisian conodont zones are recognized;in ascending order,they are:the Nicoraella germanica Zone,the Nicoraella kockeli Zone,the Paragondolella bulgarica Zone,the Neogondolella constricta Zone,the Neogondolella cornuta Zone,and the Paragondolella excelsa Zone,respectively.The first occurrence of Nicoraella kockeli defines the Bithynian-Pelsonian boundary.The Pelsonian-Illyrian boundary is defined by the first occurrence of Neogondolella constricta.The Anisian-Ladinian boundary cannot be recognized at the Shaiwa Section due to the absence of conodont indicative of the Ladinian.However,the new conodont data indicate that the uppermost strata could be very close to the boundary.The abrasion of conodont surfaces provides evidence for demonstrating reworking at the Shaiwa Section,which makes some conodonts possess a longer stratigraphic range than previously recorded.The variation in relative abundance between blade-shaped conodonts and platform conodonts indicates that segminiplanate elements probably preferred deeper and oxygenated environments whereas a restricted marine environment is more suitable for segminate elements.