Search

Modified MIL‐101(Al)‐NH2 (MIL‐101(Al)‐NH2‐net) is used as a crosslinking agent and acrylic acid (AA) as a monomer, the MIL‐101(Al)‐NH2‐net grafted polyacrylic acid (MIL‐101(Al)‐NH2‐net‐g‐PAA (MAP)) composite water‐absorbent material is synthesized using the free radical polymerization method to study the application of composite absorbent materials in water collection. The structure and morphology of the composite water‐absorbent material are characterized using Fourier transform infrared spectrometry (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), Brunauer Emmett Teller (BET), and thermogravimetric analysis (TG), and the contents of ammonium persulfate (APS), MIL‐101(Al)‐NH2‐net, and neutralization degree of AA are optimized. Under optimal conditions, the water absorption ratios of the composite materials in distilled water, tap water, and 0.9% NaCl solution are 744, 169.5, and 85.5 g g−1. In addition, the properties of collecting water vapor are investigated. At 25 °C, 50% Relative Humidity (RH), 70% RH, and 90% RH, the MAP water vapor adsorption capacity is 0.0312, 0.5760, and 1.6856 g g−1, respectively. The water vapor adsorption of MIL‐101(Al)‐NH2 and MIL‐101(Al)‐NH2 self‐polymerization products are 0.025 and 0.1278 g g−1, respectively. The result showed that autopolymerization can improve the water vapor adsorption performance. [ABSTRACT FROM AUTHOR]

Rechargeable zinc metal batteries are promising for large‐scale energy storage. However, their practical application is limited by harsh issues such as uncontrollable dendrite growth, low Coulombic efficiency, and poor temperature tolerance. Herein, a unique design strategy using γ‐valerolactone‐based electrolyte and nanocarbon‐coated aluminum substrate was reported to solve the above problems. The electrolyte with extremely low freezing point and high thermal stability enables the symmetric cells with long cycle life over a wide temperature range (−50 °C to 80 °C) due to its ability to regulate zinc nucleation and preferential epitaxial growth. Besides, the nanocarbon‐coated aluminum substrate can also promote a higher Coulombic efficiency over a wide temperature range in contrast to the low Coulombic efficiency of copper substrates with significant irreversible alloying reactions because this unique substrate with excellent chemical stabilization can homogenize the interfacial electron/ion distribution. The optimized zinc metal capacitors can operate stably under various temperature conditions (2000 cycles at 30 °C with 66 % depth of discharge and 1200 cycles at 80 °C with 50 % depth of discharge). This unique electrolyte and substrate design strategy achieves a robust zinc metal battery over a wide temperature range. [ABSTRACT FROM AUTHOR]

A high‐efficiency power management unit (PMU) with wide dynamic range for radio frequency (RF) energy harvesting system is proposed in this paper. A digital zero current switching (ZCS) and a digital maximum power point tracking (MPPT) circuits are adopted. A sub‐threshold current reference circuit and a subthreshold voltage detection circuit are proposed to reduce the power consumption of always‐on control circuits and improve the conversion efficiency at low input power. A dual‐oscillator is designed to extend the frequency range and widen the input power range with optimized power consumption under low‐end band and high‐end band, respectively. Switch size and on‐time are adjusted according to the input power, which optimizes the conversion efficiency in a wide power range. Proposed PMU is implemented in a standard 180 nm CMOS process. The post‐layout simulation results show that proposed PMU can achieve cold‐start at the input voltage of 280 mV, the power consumption to maintain the PMU is only 9.6 nW. The input power range of the PMU is 11 nW–677 μW. When the input power is 50 nW, a power conversion efficiency (PCE) of 65% is achieved, and the peak PCE can reach 93% at 23.5 μW. [ABSTRACT FROM AUTHOR]

This letter reports a 28‐GHz multi‐port magneto‐electric (ME) dipole array for 5G applications. The proposed antenna array enlarges the system polarization diversity with the capability of being utilized as a balanced antenna, a dual‐polarized antenna and a circularly polarized antenna. Co‐planar waveguide (CPW) lines are used to connect ME dipole radiators to achieve a high gain with a simple feeding structure. The proposed antenna array exhibits a −10 dB impedance bandwidth of 12.8% and a maximal peak realized gain of 13.52 dBi as a balanced antenna, and exhibits a −10 dB impedance bandwidth of 28.57%, a 3‐dB axial ratio (AR) bandwidth of 16% and a maximal peak realized gain of 12.15 dBi as a circularly polarized antenna. [ABSTRACT FROM AUTHOR]

The protein‐based superabsorbent composite FCP‐g‐PAA/Kaolinite is prepared by grafting acrylic acid (AA) into the flax cake protein (FCP) using free radical polymerization in this study. The chemical structure, thermal stability, and the morphology of the FCP‐g‐PAA/Kaolinite are characterized by Fourier transform infrared, Thermogravimetric analysis, and scanning electron microscope. The results show that AA was grafted successfully into FCP. And, it has the maximum swelling capacity where the MBA concentration, APS concentration, Kaolinite concentration, FCP concentration, neutralization degree, and reaction time was 0.13%, 1.4%, 8%, 9%, 70% and 2 h, respectively. The swelling capacity reaches 860 g/g in distilled water, 238 g/g in tap water and 78 g/g in 0.9% NaCl. In addition, its water absorbency can still reach 60% after reuse for six times and the water retention rate of the material was 70% after 12 h. Therefore, FCP has a broad application prospect as a material for preparing superabsorbent composite. [ABSTRACT FROM AUTHOR]

Lipid metabolism plays crucial roles during aging processes, but how it is regulated by diets and how it interplays with aging still remain unclear. We proposed a new optical imaging platform by integrating heavy water (D2O) probing with stimulated Raman scattering (DO‐SRS) microscopy, for the first time, to directly visualize and quantify lipid metabolism regulated by different diets and insulin signaling pathway in Drosophila fat body during aging. We found that calorie restriction, low protein diet, and (moderately) high protein and high sucrose diets enhanced lipid turnover in flies at all ages, while (moderately) high fructose and glucose diets only promoted lipid turnover in aged flies. The measured lipid turnover enhancements under diverse diets were due to different mechanisms. High protein diet shortened the lifespan while all other diets extended the lifespan. Downregulating the insulin signaling pathway enhanced lipid turnover, which is likely related to lifespan increase, while upregulating insulin signaling pathway decreased lipid turnover that would shorten the lifespan. Our study offers the first approach to directly visualize spatiotemporal alterations of lipid turnover in aging Drosophila in situ, for a better understanding of the interconnections between lipid metabolism, diets, and aging. [ABSTRACT FROM AUTHOR]

A sesbania gum‐g‐poly (acrylic acid‐co‐vinyl acetate) (SG‐g‐P (AA‐co‐VAc)) emulsion was prepared by free radical polymerization using environmental‐friendly sesbania gum (SG) as raw material and grafted with acrylic acid and vinyl acetate. It was applied to study the performance of preventing water leakage from the soil. The effects of acrylic acid/vinyl acetate (AA/VAc) monomer ratio, neutralization degree of AA, content of ammonium persulfate and polymerization temperature on the properties of emulsion were investigated. Characterization of the emulsion by FTIR, SEM, TGA, and particle size distribution showed that AA and VAc were successfully grafted onto SG. SG‐g‐P (AA‐co‐VAc) had good stability under the optimum synthesis condition. Compared to SG, the thermal stability of the product was improved. The consolidation layer was formed after the product was added to the soil, which might reduce the voids between soil particles and reduce the water penetration rate. This greatly expanded its application in the research of anti‐leakage performance. [ABSTRACT FROM AUTHOR]

Controlling charge‐spin current conversion by electric fields is crucial in spintronic devices, which can now be realized in diatom ferroelectric semiconductor GeTe. It is well demonstrated that ferroelectricity can change the spin texture in this compound. Herein, it is shown that the spin Hall conductivity (SHC) can be further tuned by ferroelectricity based on the density functional theory calculations. The spin texture variation driven by the electric fields is elucidated from the symmetry point of view, highlighting the interlocked spin and orbital degrees of freedom. It is observed that the origin of SHC can be attributed to the Rashba effect and the intrinsic spin–orbit coupling. The magnitude of one component of SHC σxyz can reach as large as 100 ℏ/e (Ω−1 cm−1) in the vicinity of the band edge, which is promising for engineering spintronic devices. The work on tunable spin transport properties via the ferroelectric polarization brings novel assets into the field of spintronics. [ABSTRACT FROM AUTHOR]

Metal–organic framework nanoparticles (MOF NPs) have emerged as an important class of materials that display significantly enhanced performance in many applications compared to bulk MOF materials; their synthesis, however, commonly involves a tedious sequence that controls particle size and surface properties in separate steps. Now, a simple strategy to access functional MOF NPs in one pot is reported that uses a polyMOF ligand possessing a polymer block for surface functionalization and a coordination block with tunable multivalency for size control. This strategy produces uniform polyMOF‐5 NPs with sizes down to 20 nm, displaying exceptional structural and colloidal stability upon exposure to ambient conditions. A detailed time‐dependent study revealed that the polyMOF NPs were formed following an aggregation‐confined crystallization mechanism. Generality was demonstrated through the synthesis of well‐defined polyUiO‐66 NPs. [ABSTRACT FROM AUTHOR]

ABSTRACT: The selective transport of ions has crucial importance in biological systems as well as modern‐day energy devices, such as batteries and fuel cells, and water purification membranes. Control over ion movement can be exerted by ligation, ion channel dimensions, solvation, and electrostatic interactions. Polyelectrolyte hydrogels can provide aligned pathways for counter ion transport but lack mechanical integrity, while polyelectrolyte membranes typically suffer from the absence of an ion transport channel network. To develop polymer membranes for improved ion transport, we present the design of a novel material that combines the advantages of aligned pathways found in polyelectrolyte hydrogel and mechanical robustness in conventional membranes. The ionic species were organized via controlled copolymerization of a quaternizable monomer. Additionally, dimensional stability was then incorporated through a cast/crosslinking method to lock in the network of connected cationic groups. This strategy resulted in dramatically enhanced ion transport, as characterized by ionic conductivities (>80 mS/cm for Cl–, and ∼200 mS/cm for OH–). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 618–625 [ABSTRACT FROM AUTHOR]

ABSTRACT: Using sequential RAFT polymerization, single monomer insertion, and “click” chemistry, a series of triblock copolymers, poly(ethylene oxide)‐b‐polystyrene‐b‐poly(ethylene oxide), PEO‐b‐PS‐b‐PEO, were synthesized, where one of the two junction points is a UV cleavable ortho‐nitrobenzyl (ONB). Ordered patterns of PEO‐b‐PS‐b‐PEO were produced by solvent vapor annealing. Upon exposure to ultraviolet (UV) light, the PEO‐b‐PS‐b‐PEO was converted into a mixture of a PEO homopolymer and a PS‐b‐PEO diblock copolymer. It was found that the microdomain spacing could be tuned by adjusting the UV exposure time, due to the change in the copolymer architecture and the swelling of the PEO microdomain by the PEO homopolymer produced. By selective area exposure of the PEO‐b‐PS‐b‐PEO thin films, the domain spacing was changed over selected locations across the film, generating patterns of different microdomain sizes. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 355–361. [ABSTRACT FROM AUTHOR]

The insulating TiO2 (100) surface was transformed into conducting state after Ar+ ion irradiation, which is due to the formation of oxygen vacancies. The thickness of the conducting layer is about 5 nm according to the transmission electron microscopy, and its surface with a spatial asymmetry hosts Rashba spin-orbit coupling. A permalloy (Py) thin film was then deposited onto the irradiated TiO2 by magnetron sputtering. In this Py/TiO2 sample, an inverse Rashba-Edelstein effect (IREE) induced voltage was detected, which converted the spin current injected from Py by spin pumping into the charge current (voltage) due to the spin-orbit coupling. Through the two-step measurement with sample flipping, the voltages of the IREE at different microwave frequency and power are separated from the spin rectification effect in the Py films. The inverse Rashba-Edelstein length λIREE, which is used to characterize the spin-to-charge current conversion efficiency, is calculated to be about 0.58 nm in this work. From the similarity of the parameter, we may conclude that the effect is universal in these two dimensional electron gas hosted by the surfaces or interfaces. [ABSTRACT FROM AUTHOR]

Software defined radios typically employ digital filter banks (FBs) for channelisation. Frequency response masking (FRM) approach is used to reduce the computational complexity of the complex modulated FB with narrow transition band. A unified FRM‐based complex modulated FB structure is proposed to design sharp filters with arbitrary passband bandwidth. The proposed unified FRM‐based complex modulated FB structure with low complexity is suitable for different even‐stacked or odd‐stacked, maximally decimated or non‐maximally decimated structures. It also can be directly applied to high sampling rate systems. It is shown that the proposed unified FRM‐based complex modulated FB structure can obtain the improvement of the computational complexity compared with the other methods. [ABSTRACT FROM AUTHOR]

Nuclear protein‐1 (NUPR1) (also known as p8) is one of the genes associated with transcription factors that participate in various aspects of cancer initiation and development. However, the molecular mechanisms of NUPR1 in bladder cancer (BLCA) remain unclear. We conducted an analysis of the correlation between NUPR1 expression and related genes using the Gene Expression Omnibus (GEO) online database. We employed lentivirus‐mediated small interfering RNA (siRNA) to knockdown the expression of NUPR1 in two human BLCA cell lines. In vitro experiments were conducted to validate the impact of NUPR1 interference on BLCA and the influence of NUPR1 on the transcription of chemokine receptor‐2 (CCR2). Furthermore, transcription factors for CCR2 were predicted using the PROMO database. Co‐immunoprecipitation (Co‐IP) and immunofluorescence double staining were used to detect the binding between NUPR1 and CCAAT/enhancer binding protein γ (CEBPG). In vivo and in vitro experiments were conducted to validate that NUPR1 regulates CCR2 transcription through CEBPG. In vitro experiments indicate that the suppression of NUPR1 inhibited BLCA growth. Analysis of the GEO database revealed a positive correlation between the expression of NUPR1 and CCR2. Luciferase experiments confirmed that NUPR1 influences the transcription of CCR2. Online data indicates that CEBPG is a transcription factor for CCR2. Co‐IP and immunofluorescence double staining confirmed binding between NUPR1 and CEBPG. Luciferase assays and chromatin immunoprecipitation (ChIP) demonstrate that CEBPG regulates the transcription of CCR2. Additionally, rescue experiments at the cellular level and animal experiments validated the aforementioned mechanism. NUPR1 promotes a promotional role in BLCA, and interference with NUPR1 can inhibit the proliferation and invasive abilities of BLCA. There was a correlation between the expressions of NUPR1 and CCR2, and NUPR1 binds with CEBPG in the cell nucleus. Transcriptional regulation of CCR2 by NUPR1 may be achieved through the involvement of CEBPG. [ABSTRACT FROM AUTHOR]