A Bionanozyme with Ultrahigh Activity Enables Spatiotemporally Controlled Reactive Oxygen Species Generation for Cancer Therapy

Nanozymes hold great potential in nanomedicine, yet biotoxicity limits their clinical translation because of their uncontrolled catalytic activity, artificial inorganic components, and harsh synthesis conditions. Herein, a peroxidase-like bionanozyme with ultrahigh and photocontrolled catalytic activity through the self-assembly of biomolecules, hemin, and in situ polymerization of pyrrole in an aqueous solution is reported. Such bionanozymes leverage the specific cues of the tumor microenvironment and precise light-induced photothermal heating for spatiotemporally controlled reactive oxygen species generation in tumors. The tunable catalytic activity and excellent biocompatibility of the bionanozyme result in high cancer cell apoptosis and tumor growth inhibition in murine models with negligible biotoxicity. This work highlights the potential of biomolecule-based nanozymes for cancer-specific therapy. Bionanozymes with ultrahigh and tunable catalytic activity may lay the important foundation for more advanced nanomedicine and biosensing.     

Intrinsic Defect Limit to the Growth of Orthorhombic HfO2 and (Hf,Zr)O2 with Strong Ferroelectricity: First-Principles Insights

It is believed that promoting the fraction of ferroelectric orthorhombic phase (o-phase) through O-poor growth conditions can increase the spontaneous polarization of HfO₂ and (Hf,Zr)O₂ thin films. However, the first-principles calculations show that the growth may be limited by the easy formation of point defects in the orthorhombic and tetragonal phases of HfO₂, ZrO₂, and (Hf,Zr)O₂. Their dominant defects, O interstitial (O_i) under O-rich conditions and O vacancy (V_O) under O-poor condition, have low formation energies and quite high density (10¹⁶–10¹⁹ cm⁻³ for 800–1400 K growth temperature). Especially, O_i has negative formation energy in tetragonal HfO₂ under O-rich condition, causing non-stoichiometry and limiting the crystalline-seed formation during o-phase growth. High-density defects can cause disordering of dipole moments and increase leakage current, both diminishing the polarization. These results explain the experimental puzzle that the measured polarization is much lower than the ideal value even in O-poor thin films and highlight that controlling defects is as important as promoting the o-phase fraction for enhancing ferroelectricity. The O-intermediate condition (average of O-rich and O-poor conditions) and low growth temperature are proposed for fabricating HfO₂ and (Hf,Zr)O₂ with fewer defects, lower leakage current, and stronger ferroelectricity, which challenges the belief that O-poor condition is optimal.     

Euryhaline Hydrogel with Constant Swelling and Salinity-Enhanced Mechanical Strength in a Wide Salinity Range

In nature, many biological organisms possess a unique osmoregulation feature that enables them to survive in environments of different salinity, which is called euryhaline characteristics (e.g., salmon that can survive in freshwater and seawater). Drawing inspiration from these salinity-tolerant organisms, here a strategy that integrates two polymer chain segments with different salinity tolerances is reported to produce a euryhaline hydrogel with stable water retention, constant swelling properties, superoleophobicity, and low-adhesion to oil in aqueous environments over a wide range of salinity. The formation of internal dynamic complementary crosslinks is a key structural factor of the euryhaline attributes. The euryhaline hydrogel-coated meshes can be successfully utilized in various oil/aqueous phase separation in a wide range of salinity. Furthermore, by creating a double network with dynamic bonds, superior euryhaline hydrogel with unique salinity-enhanced mechanical strength can be obtained. It is anticipated that the euryhaline hydrogel will have broad application prospects in complex and variable ionic environments.     

Bioinspired Intrinsic Versatile Hydrogel Fabricated by Amyloidal Toxin Simulant-Based Nanofibrous Assemblies for Accelerated Diabetic Wound Healing

Persistent microbial infection and decreased neovascularization are common issues associated with diabetic wound treatment. Hydrogel dressings that offer intrinsic antibacterial and angiogenesis-inducing may substantially avoid the use of antibiotics or angiogenic agents. Herein, a versatile hydrogel is fabricated using an amyloid-derived toxin simulant (Fmoc-LFKFFK-NH₂, FLN) as building blocks, inspired by the defense strategy of Staphylococcus aureus (S. aureus). The simulant assemblies of the hydrogel function as both matrix components and functional elements for diabetic wound treatment. The hydrogel undergoes quick assembly from random monomers to nanofibrils with abundant b-sheet driven by multiple non-covalent interactions. The developed hydrogel demonstrates excellent biocompatibility and accelerates angiogenesis via hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor A (VEGFA) signaling as a consequence of its amyloidal structure. The simulant-based nanofibrils endow the hydrogel with broad-spectrum antibacterial activity dominated by a membrane-disruption mechanism. In addition, the hydrogel exhibits excellent performance compared with the commercial hydrogel Prontosan in accelerating wound healing of diabetic mice infected with methicillin-resistant S. aureus (MRSA). This study highlights the fabrication of a single component and versatile hydrogel platform, thereby avoiding the drug-related side effects and complicated preparations and demonstrating its profound potential as a clinical dressing for the management of microbe-infected diabetic wounds.     

汽车电子辐射抗扰度测试用带状线的研制

根据汽车电子电器组件的辐射抗扰度测试的要求,研制了一套带状线测试装置.利用仿真软件对带状线装置进行结构优化设计,分析了该带状线装置的场强分布.研制的带状线装置的特性阻抗为50 Ω,在300 kHz～400 MHz的频率范围内,电压驻波比(VSWR)小于1.25.当注入20W的信号功率时,带状线装置的测试区最大能产生200 V/m的电场强度.     

"新能源发电技术"课程教学改革研究与实践

为适应新的军事能源需求,我院开设了"新能源发电技术"课程.本文针对该课程教学中存在的内容多学时少的矛盾和如何提高学员自主学习及创新能力的问题,从教学内容、教学方法、实验教学和实践环节上进行了一些改革,以充分调动学员的学习积极性,提高学员的自主学习能力、实践动手能力和创新思维能力.     

"电气传动"课程设计教学内容改革

以模拟电路控制直流调速系统为背景的"电气传动"课程设计传统教学内容已不再符合教学要求,因此需要对其进行改革.本文以数字直流双闭环调速系统为例,阐述了直流双闭环调速系统的数字化设计方法.实践表明,以数字直流双闭环调速系统设计为教学内容开展"电气传动"课程设计的改革,可以使学生更快地学习和掌握当前电机调速的新技术和新方法,同时培养了学生的创新思维能力和实践动手能力.     

倒圆角三角型两轴柔性支撑设计

为提高压电陶瓷驱动的快速反射镜的回转精度,对倒圆角三角型柔性支撑进行研究。首先利用卡氏第二定理推导出倒圆角三角型柔性铰链柔度和回转精度理论计算公式;然后建立倒圆角三角型柔性铰链和两轴柔性支撑的有限元模型,并进行仿真分析得出柔度和回转精度的仿真值。将仿真值与理论值进行比较,其结果表明,最大误差在8%以内,验证了所推导公式的准确性。对比直圆型柔性支撑,在保证柔度的前提下,倒圆角三角型柔性支撑的回转精度提高了40%,具有重要的工程实用价值。     

Single Crystal Perovskite Solar Cells: Development and Perspectives

The efficiency of perovskite solar cells has increased to a certified value of 25.2% in the past 10 years, benefiting from the superior properties of metal halide perovskite materials. Compared with the widely investigated polycrystalline thin films, single crystal perovskites without grain boundaries have better optoelectronic properties, showing great potential for photovoltaics with higher efficiency and stability. Additionally, single crystal perovskite solar cells are a fantastic model system for further investigating the working principles related to the surface and grain boundaries of perovskite materials. Unfortunately, only a handful of groups have participated in the development of single crystal perovskite solar cells; thus, the development of this area lags far behind that of its polycrystalline counterpart. Therefore, a review paper that discusses the recent developments and challenges of single crystal perovskite solar cells is urgently required to provide guidelines for this emerging field. In this progress report, the optical and electrical properties of single crystal and polycrystalline perovskite thin films are compared, followed by the recent developments in the growth of single crystal perovskite thin films and the photovoltaic applications of this material. Finally, the challenges and perspectives of single crystal perovskite solar cells are discussed in detail.     

基于非局部的图像去噪方法的发展现状综述

通过对图像的相似块做处理从而达到去噪目的,是当前较为新颖的去噪方法,在对国内外利用相似块去噪文献进行理解和分析的基础上,回顾相似块去噪研究的发展,阐明相似块去噪的原理,并总结了相似块去噪的各种方法。最终基于对相似块去噪方法的分析,提出了对其研究方法的展望。