Recent advances in anisotropic two-dimensional materials and device applications

Two-dimensional(2D)materials,such as transition metal dichalcogenides(TMDs),black phosphorus(BP),MXene and borophene,have aroused extensive attention since the discovery of graphene in 2004.They have wide range of applications in many research fields,such as optoelectronic devices,energy storage,catalysis,owing to their striking physical and chemical properties.Among them,anisotropic 2D material is one kind of 2D materials that possess different properties along different directions caused by the intrinsic anisotropic atoms5 arrangement of the 2D materials,mainly including BP,borophene,low-symmetry TMDs(ReSe2 and ReSa)and group IV monochalcogenides(SnS,SnSe,GeS,and GeSe).Recently,a series of new devices has been fabricated based on these anisotropic 2D materials.In this review,we start from a brief introduction of the classifications,crystal structures,preparation techniques,stability,as well as the strategy to discriminate the anisotropic characteristics of 2D materials.Then,the recent advanced applications including electronic devices,optoelectronic devices,thermoelectric devices and nanomechanical devices based on the anisotropic 2D materials both in experiment and theory have been summarized.Finally,the current challenges and prospects in device designs,integration,mechanical analysis,and micro-/nano-fabrication techniques related to anisotropic 2D materials have been discussed.This review is aimed to give a generalized knowledge of anisotropic 2D materials and their current devices applications,and thus inspiring the exploration and development of other kinds of new anisotropic 2D materials and various novel device applications.     

Recent advances in laser synthesis of single-walled carbon nanotubes

Very shortly following the discovery of single-walled carbon nanotubes laser-based methods emerged as reliable ways to produce moderate quantities with very consistent composition and properties. They have also proven to be good platforms for the systematic investigation of various synthesis parameters in the hope of better understanding the growth process. Several variations exist with differences such as laser wavelength, number of lasers, background temperature, and target composition. A number of common elements have emerged for the production of both high quality and high yields of SWNT, such as the effectiveness of bimetal catalysts like CoNi and NiY, and the need for high process temperatures and controlling the rate of cooling. Combined with the growing amount of in situ diagnostic and computational modelling data we are slowly making progress towards understanding the growth process. This article will present an overview of recent advancements in laser-based synthesis methods and what information can be extracted about the growth process.     

Recent progress on the synthesis and applications of carbon based nanostructures

This article reviews the latest developments in the synthesis of Graphene, Carbon nanotubes and graphene/CNT based devices based on patents, patent applications and articles published in the last two years. A brief introduction about CNT and Graphene is presented, followed by the latest techniques and advanced processing for the large scale synthesis of Graphene and CNTs. Furthermore, a brief account of emerging devices based on applications of CNTs and graphene not limited to sensors, high speed electronics, energy harvesting and storage applications are presented.     

Recent advances in carbon nanotube-based electronics

CNT-electronics is a field involving synthesis of carbon nanotubes-based novel electronic circuits, comparable to the size of molecules, the practically fundamental size possible. It has brought a new paradigm in science as it has enabled scientists to increase the device integration density tremendously, hence achieving better efficiency and speed. Here we review the state-of-art current research on the applications of CNTs in electronics and present recent results outlining their potential along with illustrating some current concerns in the research field. Unconventional projects such as CNT-based biological sensors, transistors, field emitters, integrated circuits, etc. are taking CNT-based electronics to its extremes. The field holds a promise for mass production of high speed and efficient electronic devices. However, the chemical complexity, reproducibility and other factors make the field a challenging one, which need to be addressed before the field realizes its true potential.     

Recent advances in iron-based superconductors toward applications

Iron with a large magnetic moment was widely believed to be harmful to the emergence of superconductivity because of the competition between the static ordering of electron spins and the dynamic formation of electron pairs (Cooper pairs). Thus, the discovery of a high critical temperature (T_c) iron-based superconductor (IBSC) in 2008 was accepted with surprise in the condensed matter community and rekindled extensive study globally. IBSCs have since grown to become a new class of high-T_c superconductors next to the high-T_c cuprates discovered in 1986. The rapid research progress in the science and technology of IBSCs over the past decade has resulted in the accumulation of a vast amount of knowledge on IBSC materials, mechanisms, properties, and applications with the publication of more than several tens of thousands of papers. This article reviews recent progress in the technical applications (bulk magnets, thin films, and wires) of IBSCs in addition to their fundamental material characteristics. Highlights of their applications include high-field bulk magnets workable at 15–25 K, thin films with high critical current density (J_c) > 1 MA/cm² at ～10 T and 4 K, and an average J_c of 1.3 × 10⁴ A/cm² at 10 T and 4 K achieved for a 100-m-class-length wire. These achievements are based on the intrinsically advantageous properties of IBSCs such as the higher crystallographic symmetry of the superconducting phase, higher critical magnetic field, and larger critical grain boundary angle to maintain high J_c. These properties also make IBSCs promising for applications using high magnetic fields.     

无机陶瓷膜应用过程研究的进展

从无机膜的微观结构、膜材料表面性质、应用体系的性质以及操作参数对膜分离性能的影响进行了综述与分析,认为不同因素对膜过滤性能影响规律的研究是进行膜和膜过程优化设计的基础,通过建立面向应用过程的膜材料设计的理论框架,有可能实现膜材料设计与过程工艺参数的协同优化,从而达到降低浓差极化和膜污染、提高膜过程综合效益的目的．     

生物降解聚合物合成研究进展

近年来,在生物降解聚合物合成研究方面已取得许多重要进展.由于合成聚乳酸类生物医用降解材料的最常用的催化剂辛酸亚锡Sn(Oct)2的细胞毒性问题已在世界范围内引起日益深切的关注,近年来国内外学者已研究开发出许多性能优异的低毒、非锡金属络合物催化剂(如位阻西佛碱-Al络合物,Red-Al等)用于催化交酯类单体的活性、立构专一性及立构选择性聚合反应.另一个引人注目的成就是研究开发出几种可引发丙交酯类单体活性和立构专一性开环聚合的不含金属的有机催化剂,如ROH-PR3、ROH-DMAP、肌酐、醋酸六丁基胍等.这类无金属的有机催化剂,特别是仿生型有机胍类催化剂在生物医物降解材料合成方面的具有十分诱人和广阔的应用前景.     

酶的膜固定化及其应用的研究进展

酶的膜固定化作为一种重要的生物技术已经得到了广泛的应用．文章在总结传统的酶膜固定化方法的基础上,对这一领域新的进展,如光、辐射等物理技术的应用、定点固定化技术以及多酶系统共固定等作了相应的综述．此外,还对酶膜生物反应器,尤其是其在对外消旋混合物手性拆分以及污水处理方面的应用作了简要的介绍．     

磁响应性贵金属核/壳纳米复合粒子制备研究进展

磁响应的贵金属核/壳结构复合纳米粒子具有不同于单组分纳米粒子更优越的多重功能,在催化剂、光学材料、生物传感器及生物医学领域具有重要前景。从核/壳结构类型出发,综述了具有磁响应的贵金属核/壳结构纳米复合粒子的化学制备与结构特征,并简要对其应用研究进展做了讨论。     

Recent advances in creep-resistant steels for power plant applications

The higher steam temperatures and pressures required to achieve increase in thermal efficiency of fossil fuel-fired power-generation plants necessitate the use of steels with improved creep rupture strength. The 9% chromium steels developed during the last three decades are of great interest in such applications. In this report, the development of steels P91, P92 and E911 is described. It is shown that the martensitic transformation in these three steels produces high dislocation density that confers significant transient hardening. However, the dislocation density decreases during exposure at service temperatures due to recovery effects and for long-term creep strength the sub-grain structure produced under different conditions is most important. The changes in the microstructure mean that great care is needed in the extrapolation of experimental data to obtain design values. Only data from tests with rupture times above 3,000 h provide reasonable extrapolated values. It is further shown that for the 9% chromium steels, oxidation resistance in steam is not sufficiently high for their use as thin-walled components at temperatures of 600°C and above. The potential for the development of steels of higher chromium contents (above 11%) to give an improvement in steam oxidation resistance whilst maintaining creep resistance to the 9% chromium steels is discussed.     

洋葱状炭纳米粒子的无催化剂合成(英文)

描述了基于NaN3-C6Cl6混合物热解一步合成洋葱状碳纳米粒子的方法。应用EMS,XRD,Ramans研究了缓冲气体(Ar或空气)对炭产物的得率、形貌和结构的影响。产物包含洋葱炭、非晶碳和NaCl,通过简单的纯化处理即可完全除去副产物。洋葱状炭纳米粒子的形成由热解过程中压力迅速增加产生的震动波诱导苯基活性分子合并所制。     

Dendritic and hyperbranched polymers: advances in synthesis and applications

Investigations of the synthesis, characterisation and structure—property correlations of dendritic polymer have made significant progress recently. These developments have established better understanding and brought a range of potential applications into consideration.     

Hollow magnetic nanoparticles: synthesis and applications in biomedicine

Magnetic hollow particles (MHP) are widely used in biomedicine field due to their biocompatibility, low-toxicity, low-density and the large fraction void space in the MHP, which have been successfully used to encapsulate and control drugs release, and magnetic resonance imaging (MRI). This review focuses on all kinds of MHP preparation method, compares the advantages and disadvantages in the process of synthesis, and introduces especially the special formation mechanisms such as the Kirkendall effect and Ostwald ripening. Both the compatible interior space and good magnetism of magnetic hollow structures enable them promising and unique candidates as biomedicine vehicles. Particularly, the progress of MHP widely used in the biomedical engineering applications containing drug delivery and magnetic resonance imaging are described. The main problems and the directions in the future researches are pointed out.     

Recent progress on magnetic iron oxide nanoparticles: synthesis,surface functional strategies and biomedical applications

Abstract

This review focuses on the recent development and various strategies in the preparation, microstructure, and magnetic properties of bare and surface functionalized iron oxide nanoparticles (IONPs); their corresponding biological application was also discussed. In order to implement the practical in vivo or in vitro applications, the IONPs must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of IONPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The new functionalized strategies, problems and major challenges, along with the current directions for the synthesis, surface functionalization and bioapplication of IONPs, are considered. Finally, some future trends and the prospects in these research areas are also discussed.     

Recent advances and perspectives on starch nanocomposites for packaging applications

Starch nanocomposites are popular and abundant materials in packaging sectors. The aim of this work is to review some of the most popular starch nanocomposite systems that have been used nowadays. Due to a wide range of applicable reinforcements, nanocomposite systems are investigated based on nanofiller type such as nanoclays, polysaccharides and carbonaceous nanofillers. Furthermore, the structures of starch and material preparation methods for their nanocomposites are also mentioned in this review. It is clearly presented that mechanical, thermal and barrier properties of plasticised starch can be improved with well-dispersed nanofillers in starch nanocomposites.     

Recent progress on magnetic iron oxide nanoparticles: synthesis,surface functional strategies and biomedical applications

This review focuses on the recent development and various strategies in the preparation, microstructure, and magnetic properties of bare and surface functionalized iron oxide nanoparticles (IONPs); their corresponding biological application was also discussed. In order to implement the practical in vivo or in vitro applications, the IONPs must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of IONPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The new functionalized strategies, problems and major challenges, along with the current directions for the synthesis, surface functionalization and bioapplication of IONPs, are considered. Finally, some future trends and the prospects in these research areas are also discussed.     

Recent advances in the preparation and utilization of carbon nanotubes for hydrogen storage

Recent progress in the production, purification, and experimental and theoretical investigations of carbon nanotubes for hydrogen storage are reviewed. From the industrial point of view, the chemical vapor deposition process has shown advantages over laser ablation and electric-arc-discharge methods. The ultimate goal in nanotube synthesis should be to gain control over geometrical aspects of nanotubes, such as location and orientation, and the atomic structure of nanotubes, including helicity and diameter. There is currently no effective and simple purification procedure that fulfills all requirements for processing carbon nanotubes. Purification is still the bottleneck for technical applications, especially where large amounts of material are required. Although the alkalimetal-doped carbon nanotubes showed high H2 weight uptake, further investigations indicated that some of this uptake was due to water rather than hydrogen. This discovery indicates a potential source of error in evaluation of the storage capacity of doped carbon nanotubes. Nevertheless, currently available single-wall nanotubes yield a hydrogen uptake value near 4 wt% under moderate pressure and room temperature. A further 50% increase is needed to meet U.S. Department of Energy targets for commercial exploitation. Meeting this target will require combining experimental and theoretical efforts to achieve a full understanding of the adsorption process, so that the uptake can be rationally optimized to commercially attractive levels. Large-scale production and purification of carbon nanotubes and remarkable improvement of H2 storage capacity in carbon nanotubes represent significant technological and theoretical challenges in the years to come.     

Recent advances in the synthesis of conducting polymers from the vapour phase

Inherently conducting polymers (ICPs) combine the electrical properties of metals and semiconductors with a polymer’s ability to flex and/or stretch. In general, polymers are relatively simple to synthesise, however, ICPs themselves have had limited uptake in consumer devices. This lack of uptake is in part related to the insolubility of many ICPs in common industrial solvents, and hence methods to manufacture them in a usable form have been problematic. Vapour phase polymerisation (VPP) is one method that provides a convenient route to producing thin films of both soluble and insoluble ICPs, and nanocomposites thereof. In this critical review the VPP process will be discussed from the fundamental viewpoint of the proposed polymerisation mechanism and the parameters affecting polymer growth for a range of different monomers (thiophene, 3-hexylthiophene, pyrrole, 3,4-ethylenedioxythiophene, etc.). Looking forward into the future, new areas of polymer design and fabrication using VPP will be discussed, such as the enhancement of ICPs through additives, and next generation device fabrication based upon VPP ICPs.     

Recent advances and future challenges in the use of nanoparticles for the dispersal of infectious biofilms

Increasing occurrence of intrinsically antimicrobial-resistant,human pathogens and the protective biofilm-mode in which they grow,dictates a need for the alternative control of infectious biofilms.Biofilm bacteria utilize dispersal mechanisms to detach parts of a biofilm as part of the biofilm life-cycle during times of nutrient scarcity or overpopulation.We here identify recent advances and future challenges in the development of dispersants as a new infection-control strategy.Deoxyribonuclease(DNase)and other extracellular enzymes can disrupt the extracellular matrix of a biofilm to cause dispersal.Also,a variety of small molecules,reactive oxygen species,nitric oxide releasing compounds,peptides and molecules regulating signaling pathways in biofilms have been described as dispersants.On their own,dispersants do not inhibit bacterial growth or kill bacterial pathogens.Both natural,as well as artificial dispersants,are unstable and hydrophobic which necessitate their encapsulation in smart nanocarriers,like pH-responsive micelles,liposomes or hydrogels.Depending on their composition,nanoparticles can also possess intrinsic dispersant properties.Bacteria dispersed from an infectious biofilm end up in the blood circulation where they are cleared by host immune cells.However,this sudden increase in bacte-rial concentration can also cause sepsis.Simultaneous antibiotic loading of nanoparticles with dispersant properties or combined administration of dispersants and antibiotics can counter this threat.Importantly,biofilm remaining after dispersant administration appears more susceptible to existing antibiotics.Being part of the natural biofilm life-cycle,no signs of"dispersant-resistance"have been observed.Dispersants are therewith promising for the control of infectious biofilms.