Self-Mineralizing Dnazyme Hydrogel as a Multifaceted Bone Microenvironment Amendment for Promoting Osteogenesis in Osteoporosis

The accumulation of reactive oxygen species (ROS) and minimal osteogenic raw material in the osteoporotic bone microenvironment greatly inhibits the activity of osteoblasts. Herein, it is originally proposed to construct a biomatrix multifaceted bone microenvironment amendment -Mineralized zippered G4-Hemin DNAzyme hydrogel (MDH)-to improve osteoporotic osteogenic capacity and promote high-quality bone defect repair. The programmed design of the rolling circle amplified DNA hydrogel synthesis system allows the introduction of massive amounts of zippered G4-Hemin DNAzyme in MDH. The zippered G4-Hemin DNAzyme highly mimics the tight catalytic configuration of horseradish peroxidase and exerts excellent enzyme-like activity with considerable ROS molecule scavenging ability. In addition, the DNA amplification by-product pyrophosphate is ingeniously employed as a sufficient phosphorus source, thus constituting an autonomous mineralization system for waste reuse through the introduction of pyrophosphate hydrolase and calcium ions, which deposits in MDH as an osteogenic raw material and addresses the challenge of DNA hydrogel bio-application stability. The remarkable in vitro and in vivo outcomes demonstrate that MDH can effectively improve the oxidative stress status of osteoblasts, restore the balance of mitochondrial membrane potential, and reduce apoptosis, ultimately demonstrating superior osteogenic capacity.     

EMT 系统在磁性催化物分布检测中的应用

研究了电磁层析成像技术(EMT)在生物柴油制备过程中磁性催化物的分布检测上的应用。为了能够有效应用磁性催化物的导磁特性,在一种8线圈TMR-线圈结构的传感器阵列的基础上设计了仿真实验,比较了不同粒径大小的催化剂分布的成像结果,研究表明,该线圈结构适用于磁性催化物的分布检测。为了改进传统成像算法成像质量差、成像速度慢的缺点,研究了匹配追踪算法(CoSaMP)在图像重建上的应用,并与传统的Tikhonov算法和Landweber算法进行比较,结果表明CoSaMP算法有更好的边缘处理能力和更快的成像速度,与其他两种算法相比,图像误差平均降低了30.4%,成像速度提高了46%,有效提高了重建图像质量与速度。     

计及三相短路故障的MMC光伏并网系统电压补偿方法

模块化多电平变流器(mudular multilevel converter,MMC)在主电路结构中可以有效提高光伏并网系统的光能利用率。提出了一种光伏电站直流并网方案,通过大功率高变比的有源箝位Boost全桥隔离变换器串联升压,然后经MMC实现光伏高压直流并网。针对光伏并网后交流侧电压的稳定性,提出了基于电压前馈的双闭环控制策略。在MATLAB/Simulink中搭建串联型光伏电站经MMC并网模型,并应用基于电压前馈的双闭环控制策略,验证所提拓扑方案的正确性以及控制策略的可行性。结果表明,控制策略可以在发生三相短路故障时及时补偿电压,提高交流系统侧的可靠性。     

Optimizing emotion–cause pair extraction task by using mutual assistance single-task model,clause position information and semantic features

The traditional emotion–cause extraction task needs to give the exact emotion annotation contained in the document before extracting the cause. Different from this, the emotion–cause pair extraction (ECPE) task, which aims to extract emotion–cause pairs with causal relationships directly from the document, is a task proposed in the natural language processing field recently. At present, the task of ECPE is divided into two steps: emotion annotations and cause clause extraction, emotion–cause clause pair combining and filtering. In this article, we optimize these two steps. On the one hand, in the first step of ECPE, a mutual assistance single-task model proposed by us is used to replace the original multi-task model. On the other hand, the position information of the clause is added as an additional feature in the second step of ECPE. Furthermore, based on different levels of semantic features, we design three filtering models and explore their performance on ECPE tasks. The experimental results on the benchmark corpus show that our approach can make the ECPE task achieve better performance. Compared with the referenced method, F1-score is increased by 5.3%. Moreover, these optimization strategies improve the subtasks contained in ECPE to varying degrees.

     

Tensile Strength Evolution and Damage Mechanisms of Al–Si Piston Alloy at Different Temperatures

The Al–Si piston alloys always bear different temperatures because of its peculiar component structure and service condition. Therefore, the tensile strength, elongation to fracture, and corresponding damage mechanisms of Al12SiCuNiMg piston alloys (ASPA) have been investigated with in situ technique at different temperatures. The tensile properties show two‐stage tendencies: the former stage (25–280 °C) is determined by easily broken phases with inherent brittleness (such as primary Si), and the fracture behavior presents rapid brittle fracture after reaching the critical stress (about 430 MPa, based on in situ technique and the elastic stress field model). The later one (280–425 °C) is dominated by particles debonding and θphase coarsening. The plastic deformation behavior, dynamic recovery, and flow process become more significant on account of thermal activation. The Considère criterion h = K indicates that the transition of damage behaviors from insufficient local strength to insufficient matrix strength and the corresponding failure model shifts from brittle to ductile fracture. Based on the damage mechanisms, the elastic field model and thermal activation relation model have been established to characterize the strength of the ASPA at different temperature ranges.

     

In Situ Chelating Synthesis of Hierarchical LiNi1/3Co1/3Mn1/3O2 Polyhedron Assemblies with Ultralong Cycle Life for Li‐Ion Batteries

Layered lithium transition‐metal oxides, with large capacity and high discharge platform, are promising cathode materials for Li‐ion batteries. However, their high‐rate cycling stability still remains a large challenge. Herein, hierarchical LiNi_1/3Co_1/3Mn_1/3O₂ polyhedron assemblies are obtained through in situ chelation of transition metal ions (Ni²⁺, Co²⁺, and Mn²⁺) with amide groups uniformly distributed along the backbone of modified polyacrylonitrile chains to achieve intimate mixing at the atomic level. The assemblies exhibit outstanding electrochemical performances: superior rate capability, high volumetric energy density, and especially ultralong high‐rate cyclability, due to the superiority of unique hierarchical structures. The polyhedrons with exposed active crystal facets provide more channels for Li⁺ diffusion, and meso/macropores serve as access shortcuts for fast migration of electrolytes, Li⁺ and electrons. The strategy proposed in this work can be extended to fabricate other mixed transition metal‐based materials for advanced batteries.     

非线性广义最小方差控制律综述

如何设计简单的控制策略对复杂非线性系统进行控制是控制界还未解决的难题．非线性广义最小方差控制律的提出使得非线性控制器的设计可以基于更为一般的非线性模型，并且控制器易于实现．整个系统包含时滞环节，稳定的非线性输入子系统和一个可以用多项式或者状态空间描述的子系统．通过最小化由误差加权项、状态加权项和输入加权项组成的信号的方差得到优化控制器．在系统为开环稳定的情况下，可用史密斯预估器进行控制．本文首先介绍了非线性广义最小方差控制的发展进程，然后综述了基于状态空间和多项式描述的系统的非线性广义最小方差控制器的设计以及其现状和今后的发展方向．     

Spray-Coating of Superhydrophobic Coatings for Advanced Applications

Superhydrophobic coatings are widely applicable, e.g., as self-cleaning surfaces or water–oil separation membranes, yet their wider usage is impeded due to costs of fabrication, size, or substrate limitation. Spray-coating is a versatile coating procedures and might offer a good solution for the fabrication of these superhydrophobic coatings, due to the fact that coatings can be fabricated on various materials in a simple, fast, and inexpensive manner. Most procedures rely on hybrid coatings of hydrophobized nanoparticles and a polymeric matrix, which have several drawbacks including the easy loss of nanoparticles and difficult waste handling. Here, the fabrication of the superhydrophobic material, called Fluoropor, for the first time, by spray-coating on various substrates including metals, tissues, concrete, and glass is presented. It is fabricated by spray-coating a mixture of a highly fluorinated monomer blended with porogens followed by photopolymerization. The superhydrophobicity of the material relies on the porous structure on the micro-/nanoscale across the bulk material and does not require any nanoparticles. Excellent self-cleaning ability of these coatings, resistance against thermal and abrasive impact, and their application as oil–water separation membranes are shown. This versatile applicability is highly promising for real-world application as self-cleaning coatings or oil–water separating membranes.