Solar energy absorption is a very important field in photonics. The successful development of an efficient, wide-band solar absorber is an extremely powerful driver in this field. We propose an ...ultra-wideband (UWB) solar energy absorber composed of a Ti ring and SiO
2
-Si
3
N
4
-Ti thin films. In the range of 300-4000 nm, the wide band has an absorption efficiency of more than 90% and can reach 3683 nm, and it has four absorption peaks with a high absorptivity. Moreover, the weighted average absorption efficiency of the solar absorber under AM 1.5 is maintained above 97.03%, which indicates it has great potential for use in the field of solar energy absorption. Moreover, we proved that the polarization is insensitive by analyzing the absorption characteristics at arbitrary polarization angles. For both the transverse electric (TE) and transverse magnetic (TM) modes, the UWB absorption is maintained at more than 90% in the wide incidence angle range of 60°. The UWB solar energy absorber has great potential for use in a variety of applications, such as converting solar light and heat into electricity for public use and reducing the side effects of coal-fired power generation. It can also be used in information detection and infrared thermal imaging owing to its UWB characteristics.
An ultra-wideband solar energy absorber composed of a Ti ring and a SiO
2
-Si
3
N
4
-Ti thin film is proposed. It was found that the absorption efficiency of the absorber was over 90% with a broadband of 3683 nm.
A novel multilayer terahertz metamaterial composed of double rectangle, vertical single rectangle, vertical double rectangle and single rectangle graphene layer is proposed. The dynamic adjustable ...triple plasmon induced transparency (PIT) is realized by coupling two bright modes and two dark modes, which is an especial synergy effect between two single-PIT. Coupled mode theory contained four resonators is employed to explain the triple-PIT, and the theoretical results exhibit excellent consistency with finite-difference time-domain. Surprisingly, the triple-PIT can evolve into a dual-PIT or a single-PIT only by changing the Fermi level of graphene, and the amplitude modulation degrees at the four resonance frequencies of the triple-PIT are 74.7%, 87.8%, 76.5%, and 77.7%, respectively. In addition, a simultaneous switching at multiple frequencies is realized by adjusting different Fermi levels. Therefore, this study not only lays the foundation for explaining phenomenon of the triple-PIT but also puts forward new ideas for the design of optoelectronic device.
A terahertz multifunction modulator composed of upper-layer double graphene ribbons and lower-layer a graphene strip, which can generate a Fano resonance produced by hybrid between a broad mode and a ...narrow mode, is proposed to realize electro-optical switch and filtering function. The electric field distribution, hybrid theory, and quantum level theory are all employed to explain the Fano resonance, whose transmission spectra are fitted by coupled mode theory. In comparison to other graphene-based terahertz modulators, the amplitude modulation degree can reach 99.57%, meaning an excellent electro-optical switch can be realized. Moreover, the extinction ratio of Fano resonance can reach 99.70%, demonstrating an unparalleled electro-optical filter is implemented. Finally, variations in the lateral and longitudinal lengths of the lower-layer a graphene strip enable excellent dual-band, triple-band filters. Thus, this work provides a new way to implement terahertz multi-function modulators.
The plasmon-induced transparency (PIT), which is destructive interference between the superradiation mode and the subradiation mode, is studied in patterned graphene-based terahertz metasurface ...composed of graphene ribbons and graphene strips. As the results of finite-difference time-domain (FDTD) simulation and coupled-mode theory (CMT) fitting, the PIT can be dynamically modulated by the dual-mode. The left (right) transmission dip is mainly tailored by the gate voltage applied to graphene ribbons (stripes), respectively, meaning a dual-mode on-to-off modulator is realized. Surprisingly, an absorbance of 50% and slow-light property of 0.7 ps are also achieved, demonstrating the proposed PIT metasurface has important applications in absorption and slow-light. In addition, coupling effects between the graphene ribbons and the graphene strips in PIT metasurface with different structural parameters also are studied in detail. Thus, the proposed structure provides a new basis for the dual-mode on-to-off multi-function modulators.
Dual plasmon-induced transparency (PIT) and plasmon-induced absorption (PIA) are simultaneously achieved in an integrated metamaterial composed of single layer of graphene. Electric field ...distribution and coupled mode theory (CMT) are used to demonstrate the physical mechanism of dual PIT and PIA, and the theoretical result of CMT is highly consistent with the finite-difference time-domain (FDTD) method simulation result. Further research shows that both the dual PIT and PIA phenomenon can be effectively modulated by the Fermi level, the carrier mobility of the graphene and the refractive index of the surrounding environment. It is meaningful that the absorption of the dual PIA spectrum can be abruptly increased to 93.5% when the carrier mobility of graphene is 0.8m
/Vs. In addition, the group index can be as high as 328. Thus, our work can pave new way for developing excellent slow-light and light absorption functional devices.
Aiming at non-stationary signals with complex components, the performance of a variational mode decomposition (VMD) algorithm is seriously affected by the key parameters such as the number of modes ...K, the quadratic penalty parameter α and the update step τ. In order to solve this problem, an adaptive empirical variational mode decomposition (EVMD) method based on a binary tree model is proposed in this paper, which can not only effectively solve the problem of VMD parameter selection, but also effectively reduce the computational complexity of searching the optimal VMD parameters using intelligent optimization algorithm. Firstly, the signal noise ratio (SNR) and refined composite multi-scale dispersion entropy (RCMDE) of the decomposed signal are calculated. The RCMDE is used as the setting basis of the α, and the SNR is used as the parameter value of the τ. Then, the signal is decomposed into two components based on the binary tree mode. Before decomposing, the α and τ need to be reset according to the SNR and MDE of the new signal. Finally, the cycle iteration termination condition composed of the least squares mutual information and reconstruction error of the components determines whether to continue the decomposition. The components with large least squares mutual information (LSMI) are combined, and the LSMI threshold is set as 0.8. The simulation and experimental results indicate that the proposed empirical VMD algorithm can decompose the non-stationary signals adaptively, with lower complexity, which is O(n2), good decomposition effect and strong robustness.
Double narrowband induced perfect absorption in the terahertz region is achieved in a graphene–dielectric–gold hybrid metamaterial, whose physical mechanism is analyzed using the coupled-mode theory ...(CMT), which agreed well with the finite-difference time-domain (FDTD) simulation. This study found that the Fermi level of graphene can be adjusted to improve the absorptivity when the refractive index (RI)
n
d
of the chosen dielectric cannot achieve a good absorption effect. In addition, the blue shift of absorption spectrum can be used in the design of dual-frequency electro-optical switches, of which the modulation degree of amplitude (MDA) can reach as high as 94.05% and 93.41%, indicating that this is a very promising electro-optical switch. Most significantly, the RI sensing performance is investigated, which shows an ultra-high absorption sensitivity
S
A
= 4.4°/RIU, wavelength sensitivity
S
λ
= 9.8°/RIU, and phase shift sensitivity
S
φ
= 2691°/RIU. At last, an interesting finding is that the two peaks (R1 and R2) of plasmon-induced absorption (PIA) show different polarization characteristics (insensitive or sensitive) to the incident light angle; this polarization-sensitive is particularly important for the PIT/PIA-based optical polarizers. Undoubtedly, this paper is of great significance to the research and design of terahertz photonic devices and sensors.
Circular RNAs (circRNAs) have been shown to be essential for the emergence and growth of different cancers. However, further research is required to validate the function of circRNA in glioblastoma ...(GBM).
CircNDC80 expression in both normal brain tissues (NBTs) and glioma tissues was determined using real-time PCR. The impact of circNDC80 on GBM cell proliferation, migration, and invasion was then confirmed by CCK-8, colony formation, EdU incorporation, Transwell, and wound healing assays. To determine how circNDC80 affects the capacity of glioma stem cells (GSCs) to maintain their stemness and self-renewal, a CellTiter-Glo assay, clonogenic assay and extreme limiting dilution assay were utilized. To ascertain the impact of circNDC80 in vivo, intracranial xenograft models were established.
When compared to NBT, glioblastoma tissue had a higher level of circNDC80 expression. In functional assays, circNDC80 promoted glioblastoma cell proliferation, migration, and invasion, while sustaining the stemness and fostering the self-renewal of glioma stem cells. In addition, a dual luciferase reporter assay and circRIP were used to verify that circNDC80 simultaneously affects the expression of ECE1 mRNA by sponging miR-139-5p, and a rescue experiment was used to verify the above results further.
According to our research, circNDC80 is an oncogenic factor that promotes glioblastoma through the miR-139-5p/ECE1 pathway. This implies that circNDC80 may be employed as a novel therapeutic target and a possible predictive biomarker.
Acid-activatable micelleplexes were reported for knockdown of PD-L1 in the tumor cells. In combination with Cyclin-dependent kinases 4 and 6 inhibition, micelleplex-mediated PD-L1 knockdown ...facilitated the intratumoral infiltration of CTLs, elicited protective immune response and efficiently regressed tumor growth. This study might provide novel insight for RNAi-based combinatory immunotherapy of cancer.
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Cyclin-dependent kinases 4 and 6 inhibitors (CDK4/6i) have been demonstrated to trigger antitumor immunity for tumor regression. However, the therapeutic performance of CDK4/6i-meadiated cancer immunotherapy was impaired by the immunosuppressive tumor microenvironment (ITM) due to overexpression of programmed death ligand 1 (PD-L1) on the surface of cancer cell membrane. To improve the immunotherapeutic performance of CDK4/6i, we herein developed endosomal acid-activatable micelleplex for siRNA delivery and PD-L1 knockdown in the tumor cells in vitro and in vivo. We further demonstrated that the combination of PD-L1 knockdown and CDK4/6 inhibition facilitated intratumoral infiltration of cytotoxic T lymphocytes (CTLs), and elicited protective immune response and efficiently suppressed tumor growth in vivo. This study revealed the importance of molecular design of the micelleplex for highly efficient siRNA delivery, which might provide a novel insight for RNAi-based cancer immunotherapy.
In order to diagnose an incipient fault in rotating machinery under complicated conditions, a fast sparse decomposition based on the Teager energy operator (TEO) is proposed in this paper. In this ...proposed method, firstly, the TEO is employed to enhance the envelope of the impulses, which is more sensitive to frequency and can eliminate the low-frequency harmonic component and noise; secondly, a smoothing filtering algorithm was adopted to suppress the noise in the TEO envelope; thirdly, the fault signal was reconstructed by multiplication of the filtered TEO envelope and the original fault signal; finally, sparse decomposition was used based on a generalized S-transform (GST) to obtain the sparse representation of the signal. The proposed preprocessing method using the filtered TEO can overcome the interference of high-frequency noise while maintaining the structure of fault impulses, which helps the processed signal perform better on sparse decomposition; sparse decomposition based on GST was used to represent the fault signal more quickly and more accurately. Simulation and application prove that the proposed method has good accuracy and efficiency, especially in conditions of very low SNR, such as impulses with anSNR of −8.75 dB that are submerged by noise of the same amplitude.
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