Next-generation wireless communication requires antennas with excellent performance and low-profile structures. A low-profile broadband dual-polarized base station antenna array with an artificial ...magnetic conductor (AMC) reflector and cross-polarization suppression structures is proposed. Cross-polarization is effectively suppressed by introducing the structures among the antenna elements with almost no impact on the other antenna performances, and the cross-polarization suppression mechanism is analyzed theoretically. The AMC reflector reduces the antenna profile only <inline-formula> <tex-math notation="LaTeX">0.12\lambda _{0} </tex-math></inline-formula> (<inline-formula> <tex-math notation="LaTeX">\lambda _{0} </tex-math></inline-formula> is the free-space wavelength at 4 GHz). Prototypes of the antenna element and the five-element antenna array are fabricated, and the simulated and measured results indicate that both achieve good performance over the entire operating frequency band. The antenna array has high isolation (>28 dB), a wide operating bandwidth (3.14-5.32 GHz, 51.5%), and stable radiation performances (XPD >29 dB, gain >15 dBi, FBR >37 dB). The proposed antenna array with good performance and a low profile may be a candidate for 5G communication applications.
Controlled growth of high‐quality patterned perovskite films on a large scale is essentially required for the application of this class of materials in functional integrated devices and systems. ...Herein, graphene‐assisted hydrophilic–hydrophobic surface‐induced growth of Cs‐doped FAPbI3 perovskite films with well‐patterned shapes by a one‐step spin‐coating process is developed. Such a facile fabrication technique is compatible with a range of spin‐coated perovskite materials, perovskite manufacturing processes, and substrates. By employing this growing method, controllable perovskite photodetector arrays are realized, which have not only prominent photoresponse properties with a responsivity and specific detectivity of 4.8 AW−1 and 4.2 × 1012 Jones, respectively, but also relatively small pixel‐to‐pixel variation. Moreover, the photodetectors array can function as an effective visible light image sensor with a decent spatial resolution. Holding the above merits, the proposed technique provides a convenient and effective pathway for large‐scale preparation of patterned perovskite films for multifunctional application purposes.
This study provides a method of graphene‐assisted growth of patterned perovskite films. The perovskite thin film fabricated by this method has high film‐forming quality revealed by the morphology and electrical analysis. Further study shows that the patterned perovskite films also have a good application in the image sensing field.
Reservoir computing systems utilize dynamic reservoirs having short-term memory to project features from the temporal inputs into a high-dimensional feature space. A readout function layer can then ...effectively analyze the projected features for tasks, such as classification and time-series analysis. The system can efficiently compute complex and temporal data with low-training cost, since only the readout function needs to be trained. Here we experimentally implement a reservoir computing system using a dynamic memristor array. We show that the internal ionic dynamic processes of memristors allow the memristor-based reservoir to directly process information in the temporal domain, and demonstrate that even a small hardware system with only 88 memristors can already be used for tasks, such as handwritten digit recognition. The system is also used to experimentally solve a second-order nonlinear task, and can successfully predict the expected output without knowing the form of the original dynamic transfer function.
Background
To evaluate whether patients with post‐treatment metastasis are suitable for GP first‐line palliative chemotherapy (PCT) after undergoing GP IC.
Methods
Seven hundred and forty‐six ...patients with post‐treatment metastasis after undergoing GP IC were eligible. Survival outcomes were compared.
Results
Significant differences in survival rates were observed between patients treated with GP and non‐GP chemotherapy (2‐year progression‐free survival PFS: 0.7% vs. 9.7%). We investigated survival outcomes of patients treated with GP PCT within 2 years after undergoing GP IC, treated with GP PCT 2 years after undergoing GP IC, and those of non‐GP PCT patients (2‐year PFS: 0.0%, 2.3%, 9.7%). However, there was no difference in the 2‐year PFS between the patients that received GP PCT 2 years after undergoing GP IC and the non‐GP PCT treated patients.
Conclusions
GP is not recommended for patients that have received GP IC within 2 years. Two years after undergoing GP IC, GP can be considered.
The emergence and ongoing spread of multidrug-resistant bacteria puts humans and other species at risk for potentially lethal infections. Thus, novel antibiotics or alternative approaches are needed ...to target drug-resistant bacteria, and metabolic modulation has been documented to improve antibiotic efficacy, but the relevant metabolic mechanisms require more studies. Here, we show that glutamate potentiates aminoglycoside antibiotics, resulting in improved elimination of antibiotic-resistant pathogens. When exploring the metabolic flux of glutamate, it was found that the enzymes that link the phosphoenolpyruvate (PEP)-pyruvate-AcCoA pathway to the TCA cycle were key players in this increased efficacy. Together, the PEP-pyruvate-AcCoA pathway and TCA cycle can be considered the pyruvate cycle (P cycle). Our results show that inhibition or gene depletion of the enzymes in the P cycle shut down the TCA cycle even in the presence of excess carbon sources, and that the P cycle operates routinely as a general mechanism for energy production and regulation in Escherichia coli and Edwardsiella tarda. These findings address metabolic mechanisms of metabolite-induced potentiation and fundamental questions about bacterial biochemistry and energy metabolism.
Recently, skyrmions are constructed in the system of localized spoof surface plasmons (LSSPs), showing topological robustness and near‐equidistant multi‐resonant response. Guided wave excitation of ...the LSSP skyrmions plays an elementary role in large‐scale planar integration and construction of complex networks. However, it is not investigated. In this study, the LSSP skyrmions are excited by guided waves supported by two kinds of widely used transmission lines, microstrip line and coplanar waveguide. Space‐coiling meta‐structures with different shapes that support LSSP skyrmions are etched on the ground planes as defected ground structures (DGSs). All structures including resonator, transmission line, input and output ports are in one plane. The structures are fabricated on printed circuit boards (PCBs) and the near‐equidistant multi‐resonant spectra of the LSSP skyrmions are measured. Moreover, to reduce the material loss, the structure is made on MgB2 superconducting film, and the quality factor (Q‐factor) is increased by seven times compared to the corresponding mode on PCB. This study paves the way for the massive planar integration of the LSSP skyrmions and the construction of complex networks with the LSSP skyrmions, and provides an idea for developing metasurfaces with low material loss in the microwave and terahertz bands.
The localized spoof surface plasmon (LSSP) skyrmions are excited by guided waves supported by two kinds of traditional transmission lines, microstrip line and coplanar waveguide. The structures are fabricated on printed circuit boards (PCBs) and MgB2 superconducting films. This study paves the way for the planar integration of the LSSP skyrmions and provides a new idea for developing metasurfaces with low material loss.
Feature Extraction Using Memristor Networks Sheridan, Patrick M.; Chao Du; Lu, Wei D.
IEEE transaction on neural networks and learning systems,
2016-Nov., 2016-11-00, 20161101, Volume:
27, Issue:
11
Journal Article
Crossbar arrays of memristive elements are investigated for the implementation of dictionary learning and sparse coding of natural images. A winner-take-all training algorithm, in conjunction with ...Oja's rule, is used to learn an overcomplete dictionary of feature primitives that resemble Gabor filters. The dictionary is then used in the locally competitive algorithm to form a sparse representation of input images. The impacts of device nonlinearity and parameter variations are evaluated and a compensating procedure is proposed to ensure the robustness of the sparsification. It is shown that, with proper compensation, the memristor crossbar architecture can effectively perform sparse coding with distortion comparable with ideal software implementations at high sparsity, even in the presence of large device-to-device variations in the excess of 100%.
This paper reports an optimization scheme of type-II GaAsSb/InAs/InGaAs quantum wells using the six bands k · p method. By calculating the optical gain, the optimal structures of the quantum wells ...are obtained. We observed that without an electric field, the thickness values of symmetrical quantum wells designed by the AdaGrad algorithm are 2.97, 2.81, and 6.21 nm, respectively, and the gain intensity is 6489 cm−1 that is about 1600 cm−1 higher than the original empirical design scheme. The thickness of asymmetric quantum wells designed by the Adam algorithm is 5.56, 2.72, 1.88, 3.16, and 2.46 nm under the external electric field of 75 kV/cm, respectively, and the gain intensity is 5729 cm−1 that is about 2300 cm−1 higher than the original empirical design scheme. The optimized scheme effectively suppresses the gain attenuation caused by the electric field and is helpful to improve the performance of interband cascade lasers.
•TIPA promoted the hydration of Portland cement.•TIPA facilitated the formation of calcium aluminocarbonate in cement-MP system.•TIPA promoted the mechanical strength of cement-MP mortar.
This study ...aimed to improve the mechanical properties of cement-marble powder (MP) mortar by incorporating triisopropanolamine (TIPA) to promote the optimal utilization of marble waste. In this research, the workability, compressive strength, capillary water absorption, hydration process and microstructure of cement-MP system were investigated. From the experimental results, it was found that the incorporation of TIPA enhanced the mechanical strength of cement-MP mortar. Moreover, the capillary water absorption of cement-MP mortar was improved when the TIPA dosage exceeded 0.06%. The enhancement of these properties was mainly due to the acceleration effect of TIPA on the cement-MP system hydration process, despite the fact that its air entraining effect would have a negative effect. Incorporating TIPA in cement-MP system accelerated the dissolution of Fe3+ ions in ferrite phase to promote the hydration of cement, which certainly facilitated the consumption of SO42− ions, thus promoting the formation of calcium aluminocarbonate. Additionally, no obvious difference was observed in the workability and setting characteristics between cement-MP system with and without TIPA.
Terahertz (THz) vortex beams carrying orbital angular momentum (OAM) with high purity and tunable topological charge (TC) will undoubtedly bring extraordinary capacities for advanced imaging or ...communication systems. We propose a convenient and efficient method to generate a tunable and broadband vortex beam that is excited by superradiant Smith-Purcell radiation (SSPR) on a helical grating. This scheme fully explores the advantages of natural broadband evanescent wave carried by the electron beam and the Bloch's theorem regulated helical periodic systems. An explicit relation is established between the index of the spatial harmonic wave on the grating and the topological charge of the vortex beam. The electron energy in the SSPR can be customized to ignite the specific spatial harmonics and manipulate the OAM beam, accordingly. The separated radiation region also promises the high purity of the OAM spectrum. The harmonic excitation reduces the communality between the wavelength and the device size and alleviates the difficulty of device fabrication in the THz band. The proposed vortex scheme can not only be handily scaled to microwave and mid-infrared regions, but also bring possibilities to applications based on compact tunable vortex beam sources.
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