We study the electronic and topological properties of fully relaxed twisted bilayer (TBG) and double bilayer (TDBG) graphene under perpendicular pressure. An approach has been proposed to obtain the equilibrium in-plane structural deformation and out-of-plane corrugation in moiré superlattices under pressure. We find that the in-plane relaxation becomes much stronger under higher pressure, while the corrugation height in each layer is maintained. The comparison between band structures of relaxed and rigid structures demonstrates that not only the gaps on the electron and hole sides (∆e and ∆ h) are significantly underestimated without relaxation but also the detailed dispersions of the middle bands of rigid structures are rather different from those of relaxed systems. ∆e and ∆ h in TBG reach maximum values around critical pressures with narrowest middle bands. Topological transitions occur in TDBG under pressure with the middle valence and conduction bands in one valley touching and their Chern numbers transferred to each other. The pressure can also tune the gap at the neutrality point of TDBG, which becomes closed for a pressure range and reopened under higher pressure. The behavior of electronic structure of supertlattices under pressure is sensitive to the twist angle θ with the critical pressures generally increase with θ.

A new microstrip ultra-wideband (UWB) differential bandpass filter using two broadband planar Marchand baluns is proposed. Based on the transversal signal-interference concept, a passband with adjustable fractional bandwidth from 80 to 124% can be achieved for the differential mode, while the common mode can easily be suppressed in the whole frequency band. Good agreement is observed between simulation and measurement.

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Background Genomic imprinting results in the expression of parent-of-origin-specific alleles in the offspring. Brassica napus is an oil crop with research values in polyploidization. Identification of imprinted genes in B. napus will enrich the knowledge of genomic imprinting in dicotyledon plants. Results In this study, we performed reciprocal crosses between B. napus L. cultivars Yangyou 6 (Y6) and Zhongshuang 11 (ZS11) to collect endosperm at 20 and 25 days after pollination (DAP) for RNA-seq. In total, we identified 297 imprinted genes, including 283 maternal expressed genes (MEGs) and 14 paternal expressed genes (PEGs) according to the SNPs between Y6 and ZS11. Only 36 genes (35 MEGs and 1 PEG) were continuously imprinted in 20 and 25 DAP endosperm. We found 15, 2, 5, 3, 10, and 25 imprinted genes in this study were also imprinted in Arabidopsis, rice, castor bean, maize, B. rapa, and other B. napus lines, respectively. Only 26 imprinted genes were specifically expressed in endosperm, while other genes were also expressed in root, stem, leaf and flower bud of B. napus. A total of 109 imprinted genes were clustered on rapeseed chromosomes. We found the LTR/Copia transposable elements (TEs) were most enriched in both upstream and downstream of the imprinted genes, and the TEs enriched around imprinted genes were more than non-imprinted genes. Moreover, the expression of 5 AGLs and 6 pectin-related genes in hybrid endosperm were significantly changed comparing with that in parent endosperm. Conclusion This research provided a comprehensive identification of imprinted genes in B. napus, and enriched the gene imprinting in dicotyledon plants, which would be useful in further researches on how gene imprinting regulates seed development.

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A dual-wideband bandstop filter with high selectivity using transversal signal-interaction concept is proposed. Five transmission poles in the passband between the two stopbands can be achieved due to the superposition of signals for the two transmission paths. A planar dualwideband bandstop filter prototype for WLAN bands with 10 dB fractional bandwidths of 76.2% and 26.9% has been designed and fabricated.Introduction: With the rapid development of communication systems, high-performance and low-cost dual-wideband bandstop filters to suppress noise and spurious signals are extremely desirable. Recently, wideband bandpass filters based on the transversal signal-interaction concept have drawn a lot of attention [1][2][3][4][5]. In [1][2][3][4][5], several different methods including ring resonators, open/shorted coupled lines and baluns are used to realise ultra-wideband bandpass filters, which have the advantages of high selectivity, simple structure and flat group delay. In addition, wideband bandstop filters based on the transversal signal-interaction concept were proposed in [6][7][8]. By introducing intentionally a stopband constructive interference and out-of-band signal energy cancellations to produce power transmission zeros/poles, high-selectivity filtering responses and harmonic suppression can be achieved in these filter structures. However, little research has been done on this concept for the application of dual-wideband bandstop filters.In this Letter, a novel dual-wideband bandstop filter with high selectivity using the transversal signal-interaction concept is proposed. Two transmission paths consisting of a shunt open stub and two open coupled lines are used to realise two stopbands and multiple transmission poles for the filter. A prototype of dual-wideband bandpass filter operating at 2.1 and 5.95 GHz (10 dB bandwidths 76.2%, 26.9%) has been designed. Detailed theoretical design, simulation and experimental results are demonstrated and discussed.