Simplified Y6-Based Nonfullerene Acceptors: In-Depth Study on Molecular Structure–Property Relation,Molecular Dynamics Simulation,and Charge Dynamics

Two new Y6 derivatives of symmetrical YBO-2O and asymmetrical YBO-FO nonfullerene acceptors (NFAs) are prepared with a simplified synthetic procedure by incorporating octyl and fluorine substituents onto the terminal 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (INCN) moiety. By moving the alkyl substituents on the Y6 core to the terminal INCN moiety, the lowest unoccupied molecular orbital of the YBO NFAs increases without decreasing solubility, resulting in high open-circuit voltages of the devices. Molecular dynamics simulation shows that YBO-2O/-FO preferentially form core–core and terminal–terminal dimeric interactions, demonstrating their tighter packing structure and higher electron mobility than Y6, which is consistent with 2D grazing incidence X-ray scattering and space charge limited current measurements. In blend films, the hole transfer (HT) from YBO-2O/-FO to the polymer donor PM6 is studied in detail by transient absorption spectroscopy, demonstrating efficient HT from YBO-FO to PM6 with their suitable energy level alignment. Despite the simplified synthesis, YBO-FO demonstrates photovoltaic performance similar to that of Y6, exhibiting a power conversion efficiency of 15.01%. Overall, this design strategy not only simplifies the synthetic procedures but also adjusts the electrical properties by modifying the intermolecular packing and energy level alignment, suggesting a novel simplified molecular design of Y6 derivatives.     

Structure-Controlled Carbon Hosts for Dendrite-Free Aqueous Zinc Batteries

The surging demand for environmental-friendly and safe electrochemical energy storage systems has driven the development of aqueous zinc (Zn)-ion batteries (ZIBs). However, metallic Zn anodes suffer from severe dendrite growth and large volume change, resulting in a limited lifetime for aqueous ZIB applications. Here, it is shown that 3D mesoporous carbon (MC) with controlled carbon and defect configurations can function as a highly reversible and dendrite-free Zn host, enabling the stable operation of aqueous ZIBs. The MC host has a structure-controlled architecture that contains optimal sp²-carbon and defect sites, which results in an improved initial nucleation energy barrier and promotes uniform Zn deposition. As a consequence, the MC host shows outstanding Zn plating/stripping performance over 1000 cycles at 2 mA cm⁻² and over 250 cycles at 6 mA cm⁻² in asymmetric cells. Density functional theory calculations further reveal the role of the defective sp²-carbon surface in Zn adsorption energy. Moreover, a full cell based on Zn@MC900 anode and V₂O₅ cathode exhibits remarkable rate performance and cycling stability over 3500 cycles. These results establish a structure-mechanism-performance relationship of the carbon host as a highly reversible Zn anode for the reliable operation of ZIBs.     

Layer-Controlled Perovskite 2D Nanosheet Interlayer for the Energy Storage Performance of Nanocomposites

Polymer-based nanocomposites are desirable materials for next-generation dielectric capacitors. 2D dielectric nanosheets have received significant attention as a filler. However, randomly spreading the 2D filler causes residual stresses and agglomerated defect sites in the polymer matrix, which leads to the growth of an electric tree, resulting in a more premature breakdown than expected. Therefore, realizing a well-aligned 2D nanosheet layer with a small amount is a key challenge; it can inhibit the growth of conduction paths without degrading the performance of the material. Here, an ultrathin Sr_1.8Bi_0.2Nb₃O₁₀ (SBNO) nanosheet filler is added as a layer into poly(vinylidene fluoride) (PVDF) films via the Langmuir–Blodgett method. The structural properties, breakdown strength, and energy storage capacity of a PVDF and multilayer PVDF/SBNO/PVDF composites as a function of the thickness-controlled SBNO layer are examined. The seven-layered (only 14 nm) SBNO nanosheets thin film can sufficiently prevent the electrical path in the PVDF/SBNO/PVDF composite and shows a high energy density of 12.8 J cm⁻³ at 508 MV m⁻¹, which is significantly higher than that of the bare PVDF film (9.2 J cm⁻³ at 439 MV m⁻¹). At present, this composite has the highest energy density among the polymer-based nanocomposites under the filler of thin thickness.     

Microscopic and macroscopic approaches of Cu(II) removal by FSM-16

The removal of Cu(II) by a mesoporous material, FSM-16, was studied using electron paramagnetic resonance (EPR) spectroscopy and surface complexation modeling (SCM). Free copper ions, adsorbed and precipitated Cu(II) species were qualitatively identified by in situ EPR spectroscopy of Cu-FSM-16 suspensions at room temperature and at 77 K. In addition, the adsorbed species was identified as a Cu(II) species with an axial symmetry from an analysis of the EPR spectra of "dry" Cu-FSM-16 at 77 K. On the basis of the EPR results, the removal of Cu(II) as a function of pH under various experimental conditions was successfully simulated by assuming two removal mechanisms such as surface complexation and surface precipitation. In the acidic pH range (< pH 6), free copper ions were predominant, and surface complexed then surface precipitated species became dominant as the pH increased.     

静力疲劳荷载作用下的带预制板的连续组合双肋桥的裂缝控制

为研究裂缝控制,选取了一个带有预制板的两跨连续组合双肋梁的足尺模型,并对其进行试验及观察。在试验中,第一次荷载加到360kN,然后进行疲劳荷载试验。最后静力加载至900kN。试验结果证实了带预制板的双肋连续组合梁显示出了在静力疲劳荷载作用下的组合截面的强度和刚度特性。然而,在负弯矩作用区域,裂缝集中在内部支撑之上的桥面之间的接缝部位,初始的裂缝间距由接缝处间的距离决定,在使用荷载作用下,带有预制板的组合桥梁的桥面和横向接缝的裂缝宽度可以被控制在一个容许裂缝宽度之内。弯矩曲率曲线或者由欧洲规范4-2中规定的抗弯刚度仍可被用于评估考虑到在这种桥梁上拉伸硬化作用的有效刚度。     

Nonvolatile Memory Characteristics of NMOSFET With Ag Nanocrystals Synthesized via a Thermal Decomposition Process for Uniform Device Distribution

This paper presents nonvolatile memory characteristics using Ag nanocrystals (NCs) formed by a thermal decomposition and size-selective precipitation technique for Flash memory application. In the NC formation process, the size of NCs and the space NC-to-NC were precisely controlled by a size-selective precipitation technique and the length of the self-assembled monolayer surrounding the NCs, respectively. The size and density of the Ag NCs synthesized were typically 3-5 nm and , respectively. Due to the regularly distributed Ag NCs with high density, uniform memory characteristics and high program efficiency were achieved from NMOSFETs embedded with the Ag NCs, which were fabricated by the gate-last process.     

Stabilizing nanocrystalline Cu2O with ZnO/rGO: Engineered photoelectrodes enables efficient water splitting

The engineered photoelectrodes have received significant attention in the photoelectrochemical (PEC) applications. Herein, we prepared a highly effective photoelectrode based on Cu₂O decorated with ZnO and rGO for efficient PEC water splitting. Firstly, different thickness Cu₂O is sputtered on the FTO substrate (FC). The PEC performance of the FC photoelectrode further improved by depositing the ZnO and rGO protection layers (FCZG). The fabricated photoelectrodes are systematically investigated for their morphological and crystal structure by AFM, FESEM, TEM, XPS, XRD, and RAMAN, UVDRS, and PL analysis. The FCZG hybrid photoelectrode exhibit a photocurrent density of 4.94 mA cm^?2 at 0 V vs. reversible hydrogen electrode (RHE), which is 1.5 times higher than the unmodified photoelectrodes. The improved PEC performance of the FCZG hybrid photoelectrode is due to the high surface roughness, larger electrochemical active surface area, and less radiative recombination rate of the photogenerated charge carriers.     

Characterization of complex die-pressed Al2O3 green compact using liquid immersion,X-ray tomography,and numerical simulations

This study examined the compaction behavior of a green ceramic component with a complex shape formed by die pressing at 50 MPa using spray-dried alumina. Compared to a simple cylindrical sample, the sample with a complex shape revealed a higher degree of microstructural inhomogeneity and crack formation. Granule deformation and pore distribution at different sample locations were observed by optical microscopy after infiltrating liquid into the voids of a green compact. The refractive index of the immersion liquid should be different slightly from that of alumina for better observations. X-ray micro-computed tomography was also used to visualize the pore distribution and crack shape. Numerical simulations based on the Drucker-Prager/Cap model were performed to distinguish the stress and displacement distribution within the compact. The significant stress gradient at the crack initiation point could explain crack formation, whereas the application of a higher pressure resulted in a further increase in stress gradient.     

Quantitative study on area fraction of precipitated carbides of HP40Nb steel as a function of service period

Journal of Mechanical Science and Technology - Life assessment predictions of reformer tubes of HP40Nb grade steel used in the petrochemical industry were investigated by quantitative...     

Systematic study of an Fe2O3 stacked homojunction photoelectrochemical photoelectrode

In this study, iron (Ⅲ) oxide (Fe₂O₃) homojunction photoelectrodes were grown via the hotplate chemical bath deposition method. Various Fe₂O₃ homojunction-structured photoelectrodes have been proposed to overcome the problems such as low carrier mobility, high electron-hole recombination rate and defects due to lattice mismatch suffered by heterojunction photoelectrodes or single-layer photoelectrodes. The effects of the buffer layer, the number of stacked layers, the stacked-layer structure, and the thermal annealing treatment process on the Fe₂O₃ homojunction photoelectrode were systematically investigated. As a result, the Fe₂O₃ homojunction photoelectrode with a total of four Fe₂O₃ stacked thin films showed the best photoelectrochemical performance and was the thickest herein; it also had the highest X-ray diffraction (XRD) peak intensity for the (110) plane, the lowest XRD full-width at half maximum (FWHM), the highest donor density values, and the lowest resistance between the photoelectrode and electrolyte. This Fe₂O₃ homojunction photoelectrode with four stacked thin films showed the highest photocurrent density herein (0.54 mA/cm² at 1.64 V_RHE), which is an approximately 160% improvement over the value of the single-layer Fe₂O₃ photoelectrode.