铁电纳米材料和纳米结构研究的进展

铁电纳米材料和纳米结构(如纳米线、纳米管、纳米环)具有新型尺寸效应特性,在铁电基电子器件的微型化方面受到广泛关注.近年来在铁电纳米材料和纳米结构的制备和(电性能和微结构)表征及理论模拟方面取得了相当进展,本文对这方面的最新进展进行评述.首先对高质量的铁电纳米材料和纳米结构的制备方法进行了简短评述,然后介绍铁电纳米材料和纳米结构的纳尺度物性表征.随后介绍了最近发展的四种理论模型(尤其对铁电纳米管、纳米线、纳米点),以及从第一原理出发理论模拟铁电纳米结构的新现象,如铁电纳米结构的自发极化螺旋有序和自发极化涡旋结构.最后总结了铁电纳米材料和纳米结构的微结构研究进展,并讨论了有关铁电纳米结构中自发极化螺旋畴的一些基础物理问题以及实验上寻找自发极化螺旋畴的研究进展.     

Graphene-Based Nanomaterials for Neuroengineering: Recent Advances and Future Prospective

Graphene unique physicochemical properties made it prominent among other allotropic forms of carbon, in many areas of research and technological applications. Interestingly, in recent years, many studies exploited the use of graphene family nanomaterials (GNMs) for biomedical applications such as drug delivery, diagnostics, bioimaging, and tissue engineering research. GNMs are successfully used for the design of scaffolds for controlled induction of cell differentiation and tissue regeneration. Critically, it is important to identify the more appropriate nano/bio material interface sustaining cells differentiation and tissue regeneration enhancement. Specifically, this review is focussed on graphene-based scaffolds that endow physiochemical and biological properties suitable for a specific tissue, the nervous system, that links tightly morphological and electrical properties. Different strategies are reviewed to exploit GNMs for neuronal engineering and regeneration, material toxicity, and biocompatibility. Specifically, the potentiality for neuronal stem cells differentiation and subsequent neuronal network growth as well as the impact of electrical stimulation through GNM on cells is presented. The use of field effect transistor (FET) based on graphene for neuronal regeneration is described. This review concludes the important aspects to be controlled to make graphene a promising candidate for further advanced application in neuronal tissue engineering and biomedical use.     

Preparation,Properties, and Applications of Low-Dimensional Molecular Organic Nanomaterials

In recent years, great progress has been made in research and development of small-molecule organic materials with various low-dimensional nanostructures. This paper presents a comprehensive review of recent research progress in this field, including preparation, electronic and optoelectronic properties and applications. First, an introduction gives to the reprecipitation, soft templates methods, and progress in synthesis and morphological control of low-dimensional small-molecule organic nanomaterials. Their unique optical and electronic properties and research progress in these aspects are reviewed and discussed in detail. Applications based on low-dimensional small-molecule organic nanomaterials are briefly described. Finally, some perspectives to the future development of this field are addressed.     

Preparation,Properties,and Applications of Low-Dimensional Molecular Organic Nanomaterials

In recent years,great progress has been made in research and development of small-molecule organic materials with various low-dimensional nano-structures.This paper presents a comprehensive review of recent research progress in this field,including preparation,electronic and optoelectronic properties and applications.First,an introduction gives to the reprecipitation,soft templates methods,and progress in synthesis and morphological control of low-dimensional small-molecule organic nanomaterials.Their uniqu...     

Nanomaterials via Laser Ablation/Irradiation in Liquid: A Review

Laser ablation of solid targets in the liquid medium can be realized to fabricate nanostructures with various compositions (metals, alloys, oxides, carbides, hydroxides, etc.) and morphologies (nanoparticles, nanocubes, nanorods, nanocomposites, etc.). At the same time, the post laser irradiation of suspended nanomaterials can be applied to further modify their size, shape, and composition. Such fabrication and modification of nanomaterials in liquid based on laser irradiation has become a rapidly growing field. Compared to other, typically chemical, methods, laser ablation/irradiation in liquid (LAL) is a simple and “green” technique that normally operates in water or organic liquids under ambient conditions. Recently, the LAL has been elaborately developed to prepare a series of nanomaterials with special morphologies, microstructures and phases, and to achieve one‐step formation of various functionalized nanostructures in the pursuit of novel properties and applications in optics, display, detection, and biological fields. The formation mechanisms and synthetic strategies based on LAL are systematically analyzed and the reported nanostructures derived from the unique characteristics of LAL are highlighted along with a review of their applications and future challenges.     

NIR-II Responsive Inorganic 2D Nanomaterials for Cancer Photothermal Therapy: Recent Advances and Future Challenges

Non-invasive cancer photothermal therapy (PTT) is a promising replacement for traditional cancer treatments. The second near-infrared region induced PTT (NIR-II PTT, 1000–1500 nm) with less energy dissipation has been developed for deeper-seated tumor treatment in recent years compared with the traditional first near-infrared light (750–1000 nm). In addition, the use of emerging inorganic 2D nanomaterials as photothermal agents (PTAs) further enhanced PTT efficiency due to their intrinsic photothermal properties. NIR-II light stimulated inorganic 2D nanomaterials for PTT is becoming a hot topic in both academic and clinical fields. This review summarizes the categories, structures, and photothermal conversion properties of inorganic 2D nanomaterials for the first time. The recent synergistic strategies of NIR-II responsive PTT combined with other treatment approaches including chemotherapy, chemodynamic therapy, photodynamic therapy, radiotherapy are summarized. The future challenges and perspectives on these 2D nanomaterials for NIR-II responsive PTT systems construction are further discussed.     

溶胶-自蔓延燃烧法制备纳米材料的研究进展 推荐 下载阅读CAJ格式全文 下载阅读PDF格式全文

溶胶-自蔓延法具有溶胶-凝胶法和自蔓延法制备纳米材料的操作简单易行、无需煅烧、所得产物粒径小、分布比较均匀等优点.以硝酸盐-柠檬酸体系为例,综述了溶胶-自蔓延燃烧法的产生和发展,以及在制备一些简单纳米氧化物、以及燃料电池材料、铁氧体材料、超导粉体材料、介电陶瓷粉体材料和热敏陶瓷材料等几个方面的实际应用.最后展望了这一领域的应用和发展前景.     

Highly Sensitive Glucose Biosensors Based on Organic Electrochemical Transistors Using Platinum Gate Electrodes Modified with Enzyme and Nanomaterials

Organic electrochemical transistors with glucose oxidase‐modified Pt gate electrodes are successfully used as highly sensitive glucose sensors. The gate electrodes are modified with nanomaterials (multi‐wall carbon nanotubes or Pt nanoparticles) for the first time, which results in a dramatic improvement in the sensitivity of the devices. The detection limit of the device modified with Pt nanoparticles on the gate electrode is about 5 nM, which is three orders of magnitude better than a device without the nanoparticles. The improvement of the device performance can be attributed to the excellent electrocatalytic properties of the nanomaterials and more effective immobilization of enzyme on the gate electrodes. Based on the same principle, many other types of enzyme sensors with high sensitivity and low cost are expected to be realized by modifying the gate electrodes of organic electrochemical transistors with specific enzymes and nanomaterials.     

Assemblies of Functional Peptides and Their Applications in Building Blocks for Biosensors

This feature article highlights our recent applications of functional peptide nanotubes, self‐assembled from short peptides with recognition elements, as building blocks to develop sensors. Peptide nanotubes with high aspect ratios are excellent building blocks for a directed assembly into device configurations, and their combined structures with nanometric diameters and micrometric lengths enables to bridge the “nanoworld” and the “microworld”. When the peptide‐nanotube‐based biosensors, which incorporate molecular recognition units, apply alternating current probes to detect impedance signals, the peptide nanotubes behave as excellent building blocks of the transducer for the detection of target analyes such as pathogens, cells, and heavey metal ions with high specificity. In some sensor configurations, the electric signal can be amplified by coupling them with ion‐specific mineralization via molecular recognition of peptides. In general the detection limit of peptide nanotube chips sensors is very low and the dynamic range of detection can be widened by improved device designs.     

磁性纳米材料及其在癌症诊疗中的应用

磁性纳米材料在不同的尺寸下分别呈现出铁磁性和超顺磁性。介绍了不同形式和用途的磁性纳米材料,包括磁性纳米颗粒、磁性脂质体、磁流体、铁磁微晶玻璃、碳铁复合物、超顺磁性氧化铁等,并对近年来磁性纳米材料在磁共振成像、肿瘤细胞分离、肿瘤靶向热疗、栓塞治疗及药物磁导向方面的应用进行了综述。总结了磁性纳米材料在癌症诊断及治疗中的作用和面临的困难,并对磁性纳米材料在深部肿瘤的诊断及癌症的联合治疗、基因治疗等应用方向进行了展望。     

Recent Progress in the Synthesis of Spherical Titania Nanostructures and Their Applications

Recent progress in the fabrication and application of diverse spherical titania nanostructures, including mesoporous spheres, spherical flaky assemblies, and dendritic particles of variable diameter and monodispersity in size, is summarized in this article. Utilizing different synthesis strategies, spherical titania nanostructures with tailored polymorphs (including amorphous, anatase, rutile, brookite and TiO₂‐B), particle sizes (from tens of nanometers to millimeters), monodispersity, porosity, and variable surface properties have been produced. Such spherical titania nanostructures show realized and potential applications in the areas of chromatographic separation, lithium‐ion batteries, dye‐sensitized solar cells, photocatalytic oxidation and water splitting, photoluminescence, electrorheological fluids, catalysis, gas sensing, and anticancer intracellular drug delivery. Gaining further understanding of both synthesis design and application of these materials will promote the commercialization of such spherical titania nanostructures in the future.     

Protein Corona Influences Cell–Biomaterial Interactions in Nanostructured Tissue Engineering Scaffolds

Biomaterials are extensively used to restore damaged tissues, in the forms of implants (e.g., tissue engineered scaffolds) or biomedical devices (e.g., pacemakers). Once in contact with the physiological environment, nanostructured biomaterials undergo modifications as a result of endogenous proteins binding to their surface. The formation of this macromolecular coating complex, known as “protein corona,” onto the surface of nanoparticles and its effect on cell–particle interactions are currently under intense investigation. In striking contrast, protein corona constructs within nanostructured porous tissue engineering scaffolds remain poorly characterized. As organismal systems are highly dynamic, it is conceivable that the formation of distinct protein corona on implanted scaffolds might itself modulate cell–extracellular matrix interactions. Here, it is reported that corona complexes formed onto the fibrils of engineered collagen scaffolds display specific, distinct, and reproducible compositions that are a signature of the tissue microenvironment as well as being indicative of the subject's health condition. Protein corona formed on collagen matrices modulated cellular secretome in a context‐specific manner ex vivo, demonstrating their role in regulating scaffold–cellular interactions. Together, these findings underscore the importance of custom‐designing personalized nanostructured biomaterials, according to the biological milieu and disease state. The use of protein corona as in situ biosensor of temporal and local biomarkers is proposed.     

In-Plane Magnetic Field-Driven Creation and Annihilation of Magnetic Skyrmion Strings in Nanostructures

In bulk chiral crystals, 3D structures of magnetic skyrmions form topologically protected skyrmion strings (SkS) that have shown potential as magnonic nano-waveguides for information transfer. Although SkS stability is expected to be enhanced in nanostructures of skyrmion-hosting materials, experimental observation and detection of SkS in nanostructures under an applied in-plane magnetic field is difficult. Here, temperature-dependent magnetic field-driven creation and annihilation of SkS in B20 FeGe nanostructures (nanowires and nanoplates) under in-plane magnetic field (H_||) are shown and the mechanisms behind these transformations are explained. Unusual asymmetric and hysteretic magnetoresistance (MR) features are observed but previously unexplained during magnetic phase transitions within the SkS stability regime when H_|| is along the nanostructure's long edge, which increase the sensitivity of MR detection. Lorentz transmission electron microscopy of the SkS and other magnetic textures under H_|| in corroboration with the analysis of the anisotropic MR responses elucidates the field-driven creation and annihilation processes of SkS responsible for such hysteretic MR features and reveals an unexplored stability regime in nanostructures.     

Recent Progress on Metal-Based Nanomaterials: Fabrications,Optical Properties,and Applications in Ultrafast Photonics

Nanomaterials have demonstrated excellent mechanical, thermal, optical, and electrical properties in various fields, including 1D carbon nanotubes, as well as 2D materials starting from graphene. Metal-based nanomaterials, mainly divided into metal and metal oxide nanoparticles, also gradually come into the sight of ultrafast photonics applications due to the outstanding optical properties. The optical properties of metal nanoparticles can be enhanced by the interaction between conduction electrons with electric fields that is called surface plasmon resonance. As for metal oxide nanoparticles, optical properties are closely related to bandgap structures. When it comes to transition metal oxides, other phenomena also play important roles in optical absorption such as spin inversion and excitons of iron. Moreover, preparation methods of materials are also crucial for their properties and further applications. Therefore, in this review, commonly used physical and chemical fabrication methods for metal-based nanomaterials are first introduced. Then the optical properties of typical metal and metal oxide nanoparticles are discussed specifically. In addition, the applications of metal-based nanomaterials in ultrafast lasers based on mode-locked and Q-switched techniques are also summarized. Finally, a summary and outlook toward the synthesis, optical properties, and applications in ultrafast photonics of metal-based nanomaterials are presented.     

Inhibition of Multidrug Resistance of Cancer Cells by Co‐Delivery of DNA Nanostructures and Drugs Using Porous Silicon Nanoparticles@Giant Liposomes

Biocompatible, multifunctional, stimuli responsive, and high drug loading capacity are key factors for the new generation of drug delivery platforms. However, it is extremely challenging to create such a platform that inherits all these advanced properties in a single carrier. Herein, porous silicon nanoparticles (PSi NPs) and giant liposomes are assembled on a microfluidic chip as an advanced nano‐in‐micro platform (PSi NPs@giant liposomes), which can co‐load and co‐deliver hydrophilic and hydrophobic drugs combined with synthesized DNA nanostructures, short gold nanorods, and magnetic nanoparticles. The PSi NPs@giant liposomes with photothermal and magnetic responsiveness show good biocompatibility, high loading capacity, and controllable release. The hydrophilic thermal oxidized PSi NPs encapsulate hydrophobic therapeutics within the hydrophilic core of the giant liposomes, endowing high therapeutics loading capacity with tuneable ratio and controllable release. It is demonstrated that the DAO‐E A DNA nanostructures have synergism with drugs and importantly they contribute to the significant enhancement of cell death to doxorubicin‐resistant MCF‐7/DOX cells, overcoming the multidrug resistance in the cancer cells. Therefore, the PSi NPs@giant liposomes nano‐in‐micro platform hold great potential for a cocktail delivery of drugs and DNA nanostructures for effective cancer therapy, controllable drug release with tuneable therapeutics ratio, and both photothermal and magnetic dual responsiveness.     

Functional Nanomaterials on 2D Surfaces and in 3D Nanocomposite Hydrogels for Biomedical Applications

An emerging approach to improve the physicobiochemical properties and the multifunctionality of biomaterials is to incorporate functional nanomaterials (NMs) onto 2D surfaces and into 3D hydrogel networks. This approach is starting to generate promising advanced functional materials such as self‐assembled monolayers (SAMs) and nanocomposite (NC) hydrogels of NMs with remarkable properties and tailored functionalities that are beneficial for a variety of biomedical applications, including tissue engineering, drug delivery, and developing biosensors. A wide range of NMs, such as carbon‐, metal‐, and silica‐based NMs, can be integrated into 2D and 3D biomaterial formulations due to their unique characteristics, such as magnetic properties, electrical properties, stimuli responsiveness, hydrophobicity/hydrophilicity, and chemical composition. The highly ordered nano‐ or microscale assemblies of NMs on surfaces alter the original properties of the NMs and add enhanced and/or synergetic and novel features to the final SAMs of the NM constructs. Furthermore, the incorporation of NMs into polymeric hydrogel networks reinforces the (soft) polymer matrix such that the formed NC hydrogels show extraordinary mechanical properties with superior biological properties.     

无线局域网的技术与进展

无线局域网是９０年代计算机网络与无线通信技术相结合的产物，它提供了使用无线多址信道的一种有效方法来支持计算机之间的通信，并为通信的移动化、个人化和多媒体应用提供了潜在的手段。本文对无线局域网的概念和目前的技术发展进行了介绍，并详细分析了网络的结构、协议及其它相问题。     

Unique Seamlessly Bonded CNT@Graphene Hybrid Nanostructure Introduced in an Interlayer for Efficient and Stable Perovskite Solar Cells

Carbon nanomaterials have been widely used as an interlayer for realizing efficient and stable perovskite solar cells (PSCs). Theoretically, the design of a carbon composite interlayer that combines excellent conductivity with a high specific surface area is a better strategy than the application of pure nanocarbons. Here, an unusual seamlessly bonded carbon nanotube@graphene (CNT@G) hybrid nanomaterial was strategically synthesized and demonstrated to behave as an efficient interlayer for realizing efficient and stable PSCs. Due to the advantage of the seamless bond, the as‐proposed hybrid nanostructure showed an apparent improvement compared to the use of CNTs only, graphene only, or a simple mixture of CNTs and graphene. The power conversion efficiency improved from 15.67% to 19.56% after introduction of the hybrid nanomaterial due to efficient carrier extraction, faster charge transport, and restrained carrier recombination. More importantly, PSCs with a CNT@G hybrid‐decorated hole transport layer (HTL) showed good thermal stability during a 50 h heat‐aging test at 100 °C and water stability under ambient humidity (30–50% relative humidity) for 500 h because the hybrid nanostructure exhibited an increased capability to block ion/molecule diffusion. Our results provide an alternative approach for fully exploring the potential application of nanocarbons in the development of high‐performance PSCs.     

Recent Advances in Sensing Applications of Graphene Assemblies and Their Composites

Development of next‐generation sensor devices is gaining tremendous attention in both academia and industry because of their broad applications in manufacturing processes, food and environment control, medicine, disease diagnostics, security and defense, aerospace, and so forth. Current challenges include the development of low‐cost, ultrahigh, and user‐friendly sensors, which have high selectivity, fast response and recovery times, and small dimensions. The critical demands of these new sensors are typically associated with advanced nanoscale sensing materials. Among them, graphene and its derivatives have demonstrated the ideal properties to overcome these challenges and have merged as one of the most popular sensing platforms for diverse applications. A broad range of graphene assemblies with different architectures, morphologies, and scales (from nano‐, micro‐, to macrosize) have been explored in recent years for designing new high‐performing sensing devices. Herein, this study presents and discusses recent advances in synthesis strategies of assembled graphene‐based superstructures of 1D, 2D, and 3D macroscopic shapes in the forms of fibers, thin films, and foams/aerogels. The fabricated state‐of‐the‐art applications of these materials in gas and vapor, biomedical, piezoresistive strain and pressure, heavy metal ion, and temperature sensors are also systematically reviewed and discussed, and their sensing performance is compared.     

数字电视和压缩编码技术进展

本文首先概述数字图象与数字电视的发展前景，简单说明图象与电视数字压缩编码的必要性和可行性。接着介绍这方面的国际标准，即ＩＳＯ－ＪＰＥＧ对静止图象、ＣＣＩＴＴ－Ｈ．２６１对可视会议电话、ＩＳＯ－ＭＰＥＧ对全运动电视拟订的三种压缩编码标准。其后，介绍对全数字高清晰电视现正试验的几种制式情况。最后，概述数字电视在多媒体系统应用的发展。