Adaptive control for memristive system via compensatory controller and Chebyshev neural network.

In this paper, based on linear matrix inequality technique, a simple controller and a compensatory controller are designed. It can track arbitrary fixed points and any periodic orbits. In addition, a synchronization control method via Chebyshev neural network with external disturbances is proposed. An adaptive controller is given. The Chebyshev neural network is used to approximate the uncertain nonlinear function and the adaptive law is used to adjust the corresponding parameters in the system. Taking a 4D memristive chaotic system as examples, the results are in consistent with the simulations. From a framework and control theoretical point of view, the proposed synchronization approach via compensation controller and Chebyshev neural network is firstly presented. From an application point of view, the proposed scheme can simplify the complexity of controller design. It is promising in many applications for mem-systems as secure communications and neural networks.

Tailoring the Energy Band Structure and Interfacial Morphology of the ETL via Controllable Nanocluster Size Achieves High-Performance Planar Perovskite Solar Cells.

Planar-type perovskite solar cells (p-PSCs) based on SnO2 have garnered further attention due to their simple and low-temperature fabrication. Improving the critical properties of the electron transport layer (ETL) is an effective way to enhance the performance of p-PSC devices. Here, a brand-new method is developed to relieve the contact recombination caused by the rough fluorine-doped tin oxide (FTO) surface and further boosts the electrical concentration of the ETL. A SnO2-ethylene diamine tetraacetic acid (EDTA) acylamide compound (SEAC) with hydrogen bond-induced adjustable cluster size is reported for the first time. The rational choice of the SEAC cluster size is the key for obtaining the smooth interfacial morphology of the ETL on the rugged FTO substrate. In addition, the energy band gap decreases with the increasing cluster size, and consequently, results in improved electrical conductivity of the SEAC. The upshifted Fermi energy level leads to higher electron concentration, which is an important physical quantity of the ETL. The PSC devices based on the optimized SEAC achieve an improved power conversion efficiency of 21.29% with negligible J-V hysteresis due to significantly enhanced electron transport and reduced contact charge recombination at the ETL/perovskite interface. In general, this paper comes up with a unique strategy to improve the quality of the SnO2-based ETL.

Enhanced adsorption-based atmospheric water harvesting using a photothermal cotton rod for freshwater production in cold climates.

Solar energy-powered adsorption-based atmospheric water harvesting (ABAWH) is an emerging technology for freshwater production, especially in water-scarce regions that are remote and landlocked. Numerous water adsorbents have been used in ABAWH devices to convert molecule to liquid water. However, it is still challenging to harvest water from the air in cold winter, owing to the water adsorption of sorbents decreasing significantly at low temperature. Herein, we designed and fabricated an ABAWH device by integrating composited ionic liquids (CILs) with carbon nanotubes (CNTs) photothermal materials on the surface of cotton rod fibers. CILs extract water from the air. CNTs enable light-to-heat conversion and drive the solar evaporation process. Importantly, the cotton rods offer a backbone porous structure to maintain its internal temperature at 20 °C under solar irradiation, and thus promote the water adsorption performance of CILs at low environmental temperature. Freshwater is successfully harvested under environment temperature of 6 °C, 30% RH and solar irradiation intensity of 0.6 kW m-2. The water yield can achieve 1.49 kg per m2 per day in an outdoor environment. We believe that the ABAWH device offers a promising approach to effectively harvest water from the air at low temperature and humidity conditions.

Highly efficient and stable air-processed hole-transport-material free carbon based perovskite solar cells with caesium incorporation.

An inorganic caesium cation was incorporated into perovskite to improve the performance and stability of solar cells with a hole-transport-material free structure in ambient air. A triple cation device with a champion power conversion efficiency of over 15% was achieved, exhibiting superior thermal, long-term and operational stabilities.

Cervical hemivertebra resection and torticollis correction: report on two cases and literature review.

PURPOSE: Hemivertebra of the cervical spine is a rare but complex spinal malformation. To our knowledge, only one publication describes excision of an upper-middle cervical (between C2 and C4) hemivertebra. We present our experience with two cases of C3 hemivertebra resection and torticollis correction via a combined anterior-posterior-anterior surgical approach and short segment fixation. METHODS: Two 12-year-old patients with torticollis due to congenital C3 hemivertebra underwent surgery consisting of combined anterior vertebral body osteotomy, posterior element resection with segment instrumentation and deformity correction, and iliac bone graft reconstruction and fixation via an anterior approach. During the osteotomies, the transverse process accompanied with the vertebral artery was disconnected and freed away from the spinal column. Then the deformity was corrected without touching the vertebral artery, which made the procedure safe and comfortable. The details of this technique are presented. Pre- and postoperative radiographic features, as well as clinical outcomes were evaluated. RESULTS: The treatment process was uneventful. The patients had satisfactory clinical outcomes at a mean of 1.5 years follow-up. Head tilt and chin rotation were corrected completely. Radiographs showed favorable deformity correction, well-balanced coronal and sagittal alignment, and solid bony fusion. CONCLUSION: Combined anterior-posterior-anterior hemivertebra resection with short segment instrumentation is a reasonable option for the treatment of congenital cervical hemivertebra, which provided satisfactory deformity correction and good clinical outcomes. LEVEL OF EVIDENCE: 4.

Prognostic Factors in Skull Base Chordoma: A Systematic Literature Review and Meta-Analysis.

OBJECTIVE: Currently, there are a lack of reviews assessing the complete range of prognostic factors in skull base chordoma (SBC). This study aimed to systematically review the published literature on prognostic factors in SBC and establish pooled hazard ratios (HRs) of such factors. METHODS: MEDLINE and Embase searches (inception to April 4, 2017) were conducted. Two reviewers independently selected papers involving SBC prognostic factors, and studied them for methodologic quality and valuable factors. Pooled HRs and 95% confidence intervals (CIs) were calculated. The main end points determined were progression-free survival (PFS) and overall survival (OS). RESULTS: Twenty-two studies with 1754 subjects were included in this systematic review. However, only 18 of the studies provided sufficient data for quantitative synthesis. Preoperative visual deficit (pooled HR, 2.77; 95% CI, 1.57-4.89 for PFS), older patient age (pooled HR, 1.03; 95% CI, 1.1-1.05 for PFS; pooled HR, 1.03; 95% CI, 1.2-1.04 for OS), and nontotal or intralesional tumor resection (pooled HR, 2.01; 95% CI, 1.54-2.62 for PFS; pooled HR, 5.16; 95% CI, 2.27-11.70 for OS) were negative predictors of survival outcomes. However, adjunctive radiotherapy (pooled HR, 0.30; 95% CI, 0.16-0.56) and chondroid chordoma type (pooled HR, 0.5; 95% CI, 0.36-0.69) portended a favorable PFS. In addition, several prognostic biomarkers were promising. CONCLUSIONS: This study demonstrated that several clinicopathologic or molecular parameters are associated with survival up to tumor progression or mortality in SBC patients. However, further methodologically high-quality reports are still required to clarify the effects of these factors.

Analytical multi-soliton solutions of a (2+1)-dimensional breaking soliton equation.

The analytical solutions for a (2+1)-dimensional breaking solution equation is proposed in this paper by using mapping and projective method darboux transformation, and Some exact propagating solutions are constructed for this Breaking equation, and the M × N multi-soliton could be obtained by using Weierstrassp function and setting the perfect parameters. The potential application of breaking Soliton equation will be of great interest in future research.

Three-Dimensional Branched TiO2 Architectures in Controllable Bloom for Advanced Lithium-Ion Batteries.

Three-dimensional branched TiO2 architectures (3D BTA) with controllable morphologies were synthesized via a facile template-free one-pot solvothermal route. The volume ratio of deionized water (DI water) and diethylene glycol in solvothermal process is key to the formation of 3D BTA assembled by nanowire-coated TiO2 dendrites, which combines the advantages of 3D hierarchical structure and 1D nanoscale building blocks. Benefiting from such unique structural features, the BTA in full bloom achieved significantly increased specific surface areas and shortened Li(+) ion/electrons diffusion pathway. The lithium-ion batteries based on BTA in full bloom exhibited remarkably enhanced reversible specific capacity and rate performance, attributing to the high contact area with the electrolyte and the short solid state diffusion pathway for Li(+) ion/electrons promoting lithium insertion and extraction.