Calcium ion pinned vanadium oxide cathode for high-capacity and long-life aqueous rechargeable zinc-ion batteries

Science China Chemistry - Rechargeable aqueous zinc ion batteries (ZIBs), with the easy operation, cost effectiveness, and high safety, are emerging candidates for high-energy wearable/portable...     

Tuning Magnetic Anisotropy in a Class of Co(II) Bis(hexafluoroacetylacetonate) Complexes

Tuning the magnetic anisotropy of metal ions remains highly interesting in the design of improved single‐molecule magnets (SMMs). We herein report synthetic, structural, magnetic, and computational studies of four mononuclear Co^II complexes, namely [Co(hfac)₂(MeCN)₂] ( 1 ), [Co(hfac)₂(Spy)₂] ( 2 ), [Co(hfac)₂(MBIm)₂] ( 3 ), and [Co(hfac)₂(DMF)₂] ( 4 ) (MeCN=acetonitrile, hfac=hexafluoroacetylacetone, Spy=4‐styrylpyridine, MbIm=5,6‐dimethylbenzimidazole, DMF=N,N‐dimethylformamide), with distorted octahedral geometry constructed from hexafluoroacetylacetone (hfac) and various axial ligands. By a building block approach, complexes 2 – 4 were synthesized by recrystallization of the starting material of 1 from various ligands containing solution. Magnetic and theoretical studies reveal that 1 – 4 possess large positive D values and relative small E parameters, indicating easy‐plane magnetic anisotropy with significant rhombic anisotropy in 1 – 4 . Dynamic alternative current (ac) magnetic susceptibility measurements indicate that these complexes exhibit slow magnetic relaxation under external fields, suggesting field‐induced single‐ion magnets (SIMs) of 1 – 4 . These results provide a promising platform to achieve fine tuning of magnetic anisotropy through varying the axial ligands based on Co(II) bis(hexafluoroacetylacetonate) complexes.     

Zero‐Dimensional Hybrid Cd‐Based Perovskites with Broadband Bluish White‐Light Emissions

Recently, low‐dimensional organic‐inorganic hybrid metal halide perovskites acting as single‐component white‐light emitting materials have attracted extensive attention, but most studies concentrate on hybrid lead perovskites. Herein, we present two isomorphic zero‐dimensional (0D) hybrid cadmium perovskites, (HMEDA)CdX₄ (HMEDA=hexamethylenediamine, X=Cl ( 1 ), Br ( 2 )), which contain isolated [CdX₄]^2? anions separated by [HMEDA]²⁺ cations. Under UV light excitation, both compounds display broadband bluish white‐light emission (515 nm for 1 and 445 nm for 2 ) covering the entire visible light spectrum with sufficient photophysical stabilities. Remarkably, compound 2 shows a high color rendering index (CRI) of 83 enabling it as a promising candidate for single‐component WLED applications. Based on the temperature‐dependent, powder‐dependent and time‐resolved PL measurements as well as other detailed studies, the broadband light emissions are attributed to self‐trapped excitons stemming from the strong electron‐phonon coupling.     

Hyperbranched Poly(ester‐enamine) from Spontaneous Amino‐yne Click Reaction for Stabilization of Gold Nanoparticle Catalysts

Hyperbranched polymers have garnered much attention due to attractive properties and wide applications, such as drug‐controlled release, stimuli‐responsive nano‐objects, photosensitive materials and catalysts. Herein, two types of novel hyperbranched poly(ester‐enamine) (hb‐PEEa) were designed and synthesized via the spontaneous amino‐yne click reaction of A₂ monomer (1, 3‐bis(4‐piperidyl)‐propane (A_2a) or piperazine (A_2b)) and B₃ monomer (trimethylolpropanetripropiolate). According to Flory's hypothesis, gelation is an intrinsic problem in an ideal A₂+B₃ polymerization system. By controlling the polymerization conditions, such as monomer concentration, molar ratio and rate of addition, a non‐ideal A₂+B₃ polymerization system can be established to avoid gelation and to synthesize soluble hb‐PEEa. Due to abundant unreacted alkynyl groups in periphery, the hb‐PEEa can be further functionalized by different amino compounds or their derivates. The as‐prepared amphiphilic PEG‐hb‐PEEa copolymer can readily self‐assemble into micelles in water, which can be used as surfactant to stabilize Au nanoparticles (AuNPs) during reduction of NaBH₄ in aqueous solution. As a demonstration, the as‐prepared PEG‐hb‐PEEa‐supported AuNPs demonstrate good dispersion in water, solvent stability and remarkable catalytic activity for reduction of nitrobenzene compounds.     

Vibro-impact analysis of two adjacent cantilever beams

Nonlinear Dynamics - This study analyzes the vibro-impact behavior of two adjacent cantilever beams subjected to vibration generated by applying harmonic excitation to their rigid base. For the...     

Compensation method for complex hysteresis characteristics on piezoelectric actuator based on separated level-loop Prandtl–Ishlinskii model

Nonlinear Dynamics - Piezoelectric ceramic actuators show nonlinear hysteresis characteristics due to material properties. In order to modify the inverse piezoelectric effect as an ideal linear...     

Fixed-time disturbance observer-based robust fault-tolerant tracking control for uncertain quadrotor UAV subject to input delay

Nonlinear Dynamics - This study focuses on the design of a fixed-time disturbance observer-based robust fault-tolerant tracking control scheme for an uncertain quadrotor unmanned aerial vehicle...     

Polymerization of 2,4-hexadiyn-1,6-diol by chemical vapor deposition

2,4-Hexadiyn-1,6-diol (HDO) was polymerized on glass and silicon plates by chemical vapor deposition without transition metal catalysis to form homogeneous thin films. Structural properties of the films were investigated by FT-IR, UV-visible, Raman, x-ray diffraction, and XPS spectroscopic analyses. The structure of CVD-polymerized HDO (CVD-PHDO) films was different from that of metathesis polymerized HDO (metathesis-PHDO), showing a polyacene-based structure but no polyene structure with acetylenic side groups. © 1996 John Wiley & Sons, Inc.     

Effects of internals and distributors on the distribution and growth of bubbles in the conventional gas-solid fluidized bed

The effects of internals and gas distributors on the local dynamics of the bubbles in the conventional gas-solid fluidized bed were studied.Mesh-type internals with different opening areas(50%,70%and 90%)and different arrangements(two-layer and four-layer);and a sintered plate with a smaller pore size(1μm)and a perforated plate with a larger pore size as distributors were investigated.Differential pressure drops and local solids holdups were measured under various superficial gas velocities to compare the performances of the different types of internals and distributors.The instantaneous solids holdup signals from the optical fibre probe were used to further examine the local bubble dynamics in detail.Smaller bubbles were found,with the installation of internals or using the sintered plate,resulting in lower pressure drops and a higher bed expansion.Internals with reduced opening area or distributor with smaller pore size further leads to a higher changeover rate between the bubbles and dense phase,both axially and radially,and hence a better gas-solid contacting and an earlier transition to the turbulent flow regime of the bed.     

Application of QPLEXTM biomarkers in cognitively normal individuals across a broad age range and diverse regions with cerebral amyloid deposition

The deposition of beta-amyloid (Aβ) in the brain precedes the onset of symptoms such as cognitive impairment in Alzheimer’s disease (AD); therefore, the early detection of Aβ accumulation is crucial. We previously reported the applicability of the QPLEX^TM Alz plus assay kit for the prescreening of Aβ accumulation. Here, we tested the specific application of the kit in a large cohort of cognitively normal (CN) individuals of varying ages for the early detection of Aβ accumulation. We included a total of 221 CN participants with or without brain Aβ. The QPLEX^TM biomarkers were characterized based on age groups (1^st–3^rd tertile) and across various brain regions with cerebral amyloid deposition. The 3^rd tertile group (>65 years) was found to be the most suitable age group for the application of our assay kit. Receiver operating characteristic curve analysis showed that the area under the curve (AUC, discrimination power) was 0.878 with 69.7% sensitivity and 98.4% specificity in the 3^rd tertile group. Additionally, specific correlations between biomarkers and cerebral amyloid deposition in four different brain regions revealed an overall correlation with general amyloid deposition, consistent with previous findings. Furthermore, the combinational panel with plasma Aβ1–42 levels maximized the discrimination efficiency and achieved an AUC of 0.921 with 95.7% sensitivity and 67.3% specificity. Thus, we suggest that the QPLEX^TM Alz plus assay is useful for prescreening brain Aβ levels in CN individuals, especially those aged >65 years, to prevent disease progression via the early detection of disease initiation.Subject terms: Alzheimer''s disease, Neural ageing, ELISA