共查询到20条相似文献，搜索用时 109 毫秒
1.
2.
3.
纤维素是自然界中最丰富的可再生资源,广泛应用于生产生活诸多领域。文章简单介绍了纤维素性质结构、原料来源,并着重介绍其功能化过程,功能材料与生物功能材料的种类,以及在各行各业中的应用,展示了其广阔的发展前景。 相似文献
4.
氧化物陶瓷热电材料是一种有利于环保的新型能源转换材料.本文通过对氧化物陶瓷热电材料性能和影响因素地分析,特别是针对物性对热电性能的影响,结合实践提出了把氧化物热电材料做成多晶材料、材料的纳米结构复合化、搀杂修饰材料的能带结构等提高其性能的具体途径,用以指导具体的应用,希望具有启发意义. 相似文献
5.
Construction of sustainable high-performance structural materials is a core part of the key global sustainability goal. Many efforts have been made in this field; however, challenges remain in terms of lowering costs by using all-green basic building blocks and improving mechanical properties to meet the demand of practical applications. Here, we report a robust and efficient bottom-up strategy with micro/nanoscale structure design to regenerate an isotropic wood from natural wood particles as a high-performance sustainable structural material. Regenerated isotropic wood (RGI-wood) exceeds the limitations of the anisotropic and inconsistent mechanical properties of natural wood, having isotropic flexural strength of ∼170 MPa and flexural modulus of ∼10 GPa. RGI-wood also shows superior water resistance and fire retardancy properties to natural pine wood. Mass production of large sized RGI-wood and functional RGI-wood nanocomposites can also be achieved. 相似文献
6.
Tremendous efforts have been dedicated to developing high-performance energy storage devices based on the micro- or nano-manipulation of novel carbon electrodes, as certain nanocarbons are perceived to have advantages such as high specific surface areas, superior electric conductivities, excellent mechanical properties and so on. In typical electrochemical electrodes, ions are intercalated/deintercalated into/from the bulk (for batteries) or adsorbed/desorbed on/from the surface (for electrochemical capacitors). Fast ionic transport, significantly determined by ionic channels in active electrodes or supporting materials, is a prerequisite for the efficient energy storage with carbons. In this report, we summarize recent design strategies for ionic channels in novel carbons and give comments on the promising features based on those carbons towards tailorable ionic channels. 相似文献
7.
纳米酶代表了一类新型人工酶和生物催化剂,打破了无机与有机生命的界限。它既有纳米材料的理化特性,也有独特的类酶催化活性。同时,这些理化特性有可能会调控催化活性,使得纳米酶跟天然酶、传统的模拟酶和化学催化剂区别开来。纳米酶有比较好的稳定性、耐高温、低温、耐酸碱、活性可调且多功能,目前受到了广泛关注,在生物医药、环境治理、绿色农业、新能源等领域展现出巨大的应用前景,并初步形成了相应的学科框架。为了更好地推动纳米酶的发展,拓展对纳米酶的认识,文章回顾了纳米酶发现,分析凝练了纳米酶的学科特点及其结构,综述了纳米酶的应用,并展望了未来的发展趋势。 相似文献
8.
Linyang Li Fangyun Lu Wenqi Xiong Yu Ding Yangyi Lu Yao Xiao Xin Tong Yao Wang Shuangfeng Jia Jianbo Wang Rafael G Mendes Mark H Rümmeli Shengjun Yuan Mengqi Zeng Lei Fu 《国家科学评论(英文版)》2022,9(5)
Two-dimensional (2D) rare-earth oxides (REOs) are a large family of materials with various intriguing applications and precise facet control is essential for investigating new properties in the 2D limit. However, a bottleneck remains with regard to obtaining their 2D single crystals with specific facets because of the intrinsic non-layered structure and disparate thermodynamic stability of different facets. Herein, for the first time, we achieve the synthesis of a wide variety of high-quality 2D REO single crystals with tailorable facets via designing a hard-soft-acid-base couple for controlling the 2D nucleation of the predetermined facets and adjusting the growth mode and direction of crystals. Also, the facet-related magnetic properties of 2D REO single crystals were revealed. Our approach provides a foundation for further exploring other facet-dependent properties and various applications of 2D REO, as well as inspiration for the precise growth of other non-layered 2D materials. 相似文献
9.
有机物料对高产稻区土壤肥力影响的研究 总被引：1，自引：1，他引：1
对高产稻区土壤在氮、磷、钾化肥高水平施用条件下,投入有机物料后对土壤肥力及其产量的影响作了探讨.研究结果表明:增添有机物料后不仅使土壤有机质、速效磷、速效钾含量增加,而且对土壤的团聚水平、团聚度和结构稳定性、通气孔隙、水容量等的土壤物理性状有显著提高;土壤内在的自动调控性能增强,其抗逆性也增加.而单施化肥区土壤有机质略有下降,速效磷增加.速效钾却亏缺.尽管单化区土壤团聚水平、团聚度比试前土壤有所增加,但孔隙水平仍与试前土壤基本类似.所以土壤内在的自动调控性能和土壤的抗逆性均不及稻厩,麦厩区.因此在灾年(多雨)是稻厩、麦厩区产量较单化区分别高10.60％和14.23％,而在正常年景其产量却无明显差异,这可能与高水平化肥施用有关. 相似文献
10.
信息社会的飞速发展对信息存储、加工、传输能力提出了与日俱增的迫切需求。随着“摩尔定律”逐渐逼近极限,半导体工业急需寻求新的解决方案。二维材料因为原子级厚度的尺寸特点,表面无悬挂键的结构优势加上极大比表面积导致的对电、光等调控手段的敏感性被认为是“后摩尔定律”时代半导体工业新的突破口。松山湖材料实验室引进一批国内外顶级科学家,组建二维材料团队,以基础科研为根基,以工程应用为导向,重点攻关其中关键问题。其目标在于取得有世界级重大影响力的科研成果,布局我国二维材料产业。 相似文献
11.
Lijun Geng Mouyi Weng Cong-Qiao Xu Hanyu Zhang Chaonan Cui Haiming Wu Xin Chen Mingyu Hu Hai Lin Zhen-Dong Sun Xi Wang Han-Shi Hu Jun Li Jiaxin Zheng Zhixun Luo Feng Pan Jiannian Yao 《国家科学评论(英文版)》2021,8(1)
Exploring stable clusters to understand structural evolution from atoms to macroscopic matter and to construct new materials is interesting yet challenging in chemistry. Utilizing our newly developed deep-ultraviolet laser ionization mass spectrometry technique, here we observe the reactions of neutral cobalt clusters with oxygen and find a very stable cluster species of Co13O8 that dominates the mass distribution in the presence of a large flow rate of oxygen gas. The results of global-minimum structural search reveal a unique cubic structure and distinctive stability of the neutral Co13O8 cluster that forms a new class of metal oxides that we named as ‘metalloxocubes’. Thermodynamics and kinetics calculations illustrate the structural evolution from icosahedral Co13 to the metalloxocube Co13O8 with decreased energy, enhanced stability and aromaticity. This class of neutral oxygen-passivated metal clusters may be an ideal candidate for genetic materials because of the cubic nature of the building blocks and the stability due to cubic aromaticity. 相似文献
12.
加工过程中高分子材料形态控制的研究进展 总被引：2，自引：0，他引：2
高分子材料的性能不仅依赖于大分子的化学结构和链结构，而且在
很大程度上依
赖于结晶、取向形态及多相体系的相形态。开展高分子材料在加工过程中的热、应力场作用
下形态形成、演化、调控及“定构”研究对发展高分子成型加工基础理论、开发高性能化、
复
合化、多功能化、低成本化及清洁化高分子材料有重要意义。本文简述了加工过程中高分子
材料形态控制的研究进展，包括国内外研究现状、存在的问题和我国的差距及未来研究的重
要科学问题。 相似文献
13.
The six-membered ring (SMR) is a common structure unit for numerous material systems. These materials include, but are not limited to, the typical two-dimensional materials such as graphene, h-BN, and transition metal dichalcogenides, as well as three-dimensional materials such as beryllium, magnesium, MgB2 and Bi2Se3. Although many of these materials have already become ‘stars’ in materials science and condensed-matter physics, little attention has been paid to the roles of the SMR unit across a wide range of compositions and structures. In this article, we systematically analyze these materials with respect to their very basic SMR structural unit, which has been found to play a deterministic role in the occurrence of many intriguing properties and phenomena, such as Dirac electronic and phononic spectra, superconductivity and topology. As a result, we have defined this group of materials as SMR inorganic materials, opening up a new perspective on materials research and development. With their unique properties, SMR materials deserve wide attention and in-depth investigation from materials design, new physical discoveries to target-wizard applications. It is expected that SMR materials will find niche applications in next-generation information technology, renewable energy, space, etc. 相似文献
14.
Thermodynamic systems with variable mass, like liquid/vapor equilibria and chemical reactions, are represented as networks having discrete elements and connections using bond graph symbols. The mass bond has special properties which are explained by entropy and volume stripping and indicate the reason why the derivative of the free enthalpy, not the internal energy, is the driving effort of chemical reactions. Chemical friction is represented by RS-fields that dissipate power which is different from the observed heat rate of chemical reactions. Different reticulations apply to reactions near and far from chemical equilibrium; their relation to experimental reaction kinetics and order of reaction is discussed. 相似文献
15.
Models for chemical reaction kinetics typically assume well-mixed conditions, in which chemical compositions change in time but are uniform in space. In contrast, many biological and microfluidic systems of interest involve non-uniform flows where gradients in flow velocity dynamically alter the effective reaction volume. Here, we present a theoretical framework for characterizing multi-step reactions that occur when an enzyme or enzymatic substrate is released from a flat solid surface into a linear shear flow. Similarity solutions are developed for situations where the reactions are sufficiently slow compared to a convective time scale, allowing a regular perturbation approach to be employed. For the specific case of Michaelis-Menten reactions, we establish that the transversally averaged concentration of product scales with the distance x downstream as x(5/3). We generalize the analysis to n-step reactions, and we discuss the implications for designing new microfluidic kinetic assays to probe the effect of flow on biochemical processes. 相似文献
16.
Shunning Li Zhefeng Chen Zhi Wang Mouyi Weng Jianyuan Li Mingzheng Zhang Jing Lu Kang Xu Feng Pan 《国家科学评论(英文版)》2022,9(6)
Recent decades have witnessed an exponential growth in the discovery of low-dimensional materials (LDMs), benefiting from our unprecedented capabilities in characterizing their structure and chemistry with the aid of advanced computational techniques. Recently, the success of two-dimensional compounds has encouraged extensive research into one-dimensional (1D) atomic chains. Here, we present a methodology for topological classification of structural blocks in bulk crystals based on graph theory, leading to the identification of exfoliable 1D atomic chains and their categorization into a variety of chemical families. A subtle interplay is revealed between the prototypical 1D structural motifs and their chemical space. Leveraging the structure graphs, we elucidate the self-passivation mechanism of 1D compounds imparted by lone electron pairs, and reveal the dependence of the electronic band gap on the cationic percolation network formed by connections between structure units. This graph-theory-based formalism could serve as a source of stimuli for the future design of LDMs. 相似文献
17.
18.
To address the growing energy demands of sustainable development, it is crucial to develop new materials that can improve the efficiency of energy storage systems. Hierarchically structured porous materials have shown their great potential for energy storage applications owing to their large accessible space, high surface area, low density, excellent accommodation capability with volume and thermal variation, variable chemical compositions and well controlled and interconnected hierarchical porosity at different length scales. Porous hierarchy benefits electron and ion transport, and mass diffusion and exchange. The electrochemical behavior of hierarchically structured porous materials varies with different pore parameters. Understanding their relationship can lead to the defined and accurate design of highly efficient hierarchically structured porous materials to enhance further their energy storage performance. In this review, we take the characteristic parameters of the hierarchical pores as the survey object to summarize the recent progress on hierarchically structured porous materials for energy storage. This is the first of this kind exclusively to survey the performance of hierarchically structured porous materials from different porous characteristics. For those who are not familiar with hierarchically structured porous materials, a series of very significant synthesis strategies of hierarchically structured porous materials are firstly and briefly reviewed. This will be beneficial for those who want to quickly obtain useful reference information about the synthesis strategies of new hierarchically structured porous materials to improve their performance in energy storage. The effect of different organizational, structural and geometric parameters of porous hierarchy on their electrochemical behavior is then deeply discussed. We outline the existing problems and development challenges of hierarchically structured porous materials that need to be addressed in renewable energy applications. We hope that this review can stimulate strong intuition into the design and application of new hierarchically structured porous materials in energy storage and other fields. 相似文献
19.
20.
随着经济的快速发展和人民生活水平的提高,生物医用材料以每年超过20%的速度快速发展,并有望逐步成为21世纪世界经济的支柱产业之一。具有生物活性和降解性的第三代生物医用材料有助于解决大段组织与器官缺损的临床难题,是未来医用材料研究发展的方向。因此,为了寻找和开发新型生物医用材料,新的化学合成和表面改性方法以及材料对细胞和组织再生的作用机制成为生物医用材料研究的热点。近年来,我国在生物医用材料基础研究方面已经取得了一些新进展,但如何进一步提高研究水平,加速医用材料产业化是关系到我国生物医用材料和医疗器械产业发展亟待解决的关键问题。 相似文献