共查询到20条相似文献，搜索用时 15 毫秒
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Yi Zeng;Keliang Liu;Haibo Ding;Zhejun Chong;Yanfang Niu;Yijun Guo;Mengxiao Wei;Xin Du;Zhongze Gu; 《Small (Weinheim an der Bergstrasse, Germany)》2024,20(3):2306524
Photonic crystal hydrogels (PCHs), with smart stimulus-responsive abilities, have been widely exploited as colorimetric sensors for years. However, the current fabrication technologies are mostly applicable to produce PCHs with simple geometries at the sub-millimeter scale, limiting the introduction of structural design into PCH sensors as well as the accompanied advanced applications. This paper reports the microfabrication of three-dimensional (3D) PCHs with the help of supramolecular agarose PCH as a sacrificial scaffold by two-photon lithography (TPL). The supramolecular PCHs, formulated with SiO2 colloidal nanoparticles and agarose aqueous solutions, show bright structural color and are degradable upon short-time dimethyl sulfoxide treatment. Leveraging the supramolecular PCH as a sacrificial scaffold, PCHs with precise 3D geometries can be fabricated in an economical and efficient way. This work demonstrates the application of such a strategy in the creation of structural-designed PCH mechanical microsensors that have not been explored before. 相似文献
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Ehud Greenberg Nina Armon Omree Kapon Moshit Ben‐Ishai Hagay Shpaisman 《Advanced Materials Interfaces》2019,6(14)
Laser‐induced photothermal reaction of metal ions is a promising one‐step method for production of conductive micropatterns for electronic devices and sensors. However, the mechanism that governs the process in which thermally activated materials are deposited on a substrate is not clear. Here, light is shed on the mechanism through systematic analysis of photothermal reaction products forming iron oxide and silver at different interfaces. Examination of the nanostructure of deposits on a substrate using high‐resolution transmission electron microscopy and selected area diffraction pattern analysis reveals a combination of both amorphous and crystalline moieties. It is found that focusing the laser inside the solution leads to exclusive formation of crystalline products, while focusing at the liquid/air interface leads to formation of amorphous products due to kinetic considerations. Ring‐shaped microstructures observed on the substrate indicate that microbubbles are involved in the deposition. The findings suggest that crystalline nanoparticles formed in solution are pinned to the base of the microbubbles. These stationary deposits absorb the laser light, resulting in extensive local heating, which leads to a fast thermal‐reaction of the metal ions that are added as amorphous nanostructures. The presence of both crystalline and amorphous nanostructures therefore results from two different mechanisms. 相似文献
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Makoto Moriya 《Science and Technology of Advanced Materials》2013,14(1):634-643
AbstractIn the development of innovative molecule-based materials, the identification of the structural features in supramolecular solids and the understanding of the correlation between structure and function are important factors. The author investigated the development of supramolecular solid electrolytes by constructing ion conduction paths using a supramolecular hierarchical structure in molecular crystals because the ion conduction path is an attractive key structure due to its ability to generate solid-state ion diffusivity. The obtained molecular crystals exhibited selective lithium ion diffusion via conduction paths consisting of lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) and small molecules such as ether or amine compounds. In the present review, the correlation between the crystal structure and ion conductivity of the obtained molecular crystals is addressed based on the systematic structural control of the ionic conduction paths through the modification of the component molecules. The relationship between the crystal structure and ion conductivity of the molecular crystals provides a guideline for the development of solid electrolytes based on supramolecular solids exhibiting rapid and selective lithium ion conduction. 相似文献
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TiAl合金因具有低密度、良好的高温强度以及抗氧化性,成为在航空航天及汽车行业具有重要应用价值的新型高温结构材料。对于全片层TiAl合金,通过控制α相沿非择优取向生长,获得平行于生长方向的片层组织,可显著提高其综合力学性能。TiAl合金的片层组织控制方法主要包括改变凝固路径法和籽晶法。综述了TiAl合金片层取向控制的现状及存在的主要问题,指出自引晶法和β相籽晶法是片层取向控制的新方法,将促进TiAl合金片层组织控制的工程化应用。最后,对TiAl合金片层取向控制的发展前景进行了展望。 相似文献
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Soheyl Noparast Fernando Guevara Vasquez Mathieu Francoeur Bart Raeymaekers 《Advanced Materials Technologies》2024,9(11):2301950
Ultrasound-directed self-assembly (DSA) uses ultrasound waves to organize and orient particles dispersed in a fluid medium into specific patterns. Combining ultrasound DSA with vat photopolymerization (VP) enables manufacturing materials layer-by-layer, wherein each layer the organization and orientation of particles in the photopolymer is controlled, which enables tailoring the properties of the resulting composite materials. However, the particle packing density changes with time and location as particles organize into specific patterns. Hence, relating the ultrasound DSA process parameters to the transient local particle packing density is important to tailor the properties of the composite material, and to determine the maximum speed of the layer-by-layer VP process. This paper theoretically derives and experimentally validates a 3D ultrasound DSA model and evaluates the local particle packing density at locations where particles assemble as a function of time and ultrasound DSA process parameters. The particle packing density increases with increasing particle volume fraction, decreasing particle size, and decreasing fluid medium viscosity is determined. Increasing the particle size and decreasing the fluid medium viscosity decreases the time to reach steady-state. This work contributes to using ultrasound DSA and VP as a materials manufacturing process. 相似文献
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Zhongqi Li;Hucheng Wang;Yuliang Gao;Jingjing Chen;Guanyao Gu;Jing Liu;Yuqian Chen;Xuhong Guo;Yiming Wang; 《Small (Weinheim an der Bergstrasse, Germany)》2024,20(45):2403085
Control over the self-assembly of small molecules at specific areas is of great interest for many high-tech applications, yet remains a formidable challenge. Here, how the self-assembly of hydrazone-based molecular hydrogelators can be specifically triggered at water–water interfaces for the continuous fabrication of supramolecular microcapsules by virtue of the microfluidic technique is demonstrated. The non-assembling hydrazide- and aldehyde-based hydrogelator precursors are distributed in two immiscible aqueous polymer solutions, respectively, through spontaneous phase separation. In the presence of catalysts, hydrazone-based hydrogelators rapidly form and self-assemble into hydrogel networks at the generated water–water interfaces. Relying on the microfluidic technique, microcapsules bearing a shell of supramolecular hydrogel are continuously produced. The obtained microcapsules can effectively load enzymes, enabling localized enzymatic growth of supramolecular fibrous supramolecular structures, reminiscent of the self-assembly of biological filaments within living cells. This work may contribute to the development of biomimetic supramolecular carriers for applications in biomedicine and fundamental research, for instance, the construction of protocells. 相似文献
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Mohammed A. Ibrahem;Mohsin Waris;Md Rumon Miah;Farzan Shabani;Betul Canimkurbey;Emre Unal;Savas Delikanli;Hilmi Volkan Demir; 《Small (Weinheim an der Bergstrasse, Germany)》2024,20(30):2401423
Here, strongly orientation-dependent lateral photoconductivity of a CdSe monolayer colloidal quantum wells (CQWs) possessing short-chain ligands is reported. A controlled liquid-air self-assembly technique is utilized to deliberately engineer the alignments of CQWs into either face-down (FO) or edge-up (EO) orientation on the substrate as opposed to randomly oriented (RO) CQWs prepared by spin-coating. Adapting planar configuration metal-semiconductor-metal (MSM) photodetectors, it is found that lateral conductivity spans ≈2 orders of magnitude depending on the orientation of CQWs in the film in the case of utilizing short ligands. The long native ligands of oleic acid (OA) are exchanged with short-chain ligands of 2-ethylhexane-1-thiol (EHT) to reduce the inter-platelet distance, which significantly improved the photoresponsivity from 4.16, 0.58, and 4.79 mA W−1 to 528.7, 6.17, and 94.2 mA W−1, for the MSM devices prepared with RO, FO, and EO, before and after ligands exchange, respectively. Such CQW orientation control profoundly impacts the photodetector performance also in terms of the detection speed (0.061 s/0.074 s for the FO, 0.048 s/0.060 s for the EO compared to 0.10 s/0.16 s for the RO, for the rise and decay time constants, respectively) and the detectivity (1.7 × 1010, 2.3 × 1011, and 7.5 × 1011 Jones for the FO, EO, and RO devices, respectively) which can be further tailored for the desired optoelectronic device applications. Attributed to charge transportation in colloidal films being proportional to the number of hopping steps, these findings indicate that the solution-processed orientation of CQWs provides the ability to tune the photoconductivity of CQWs with short ligands as another degree of freedom to exploit and engineer their absorptive devices. 相似文献
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由于光纤激光的良好光束质量,光纤激光器在金属材料表面强化方面的应用日益引起学者的重视。使用YLS-3000W光纤激光器对Cr12MoV冷作模具钢进行激光表面淬火处理的工艺试验,研究了不同工艺参数对硬化层深度和显微硬度的影响及硬化层显微组织特征。结果表明,Cr12MoV表面经光纤激光表面淬火后得到淬火层、过渡层和基体3层不同的组织。淬火层的晶粒细小,由隐晶马氏体、弥散分布的碳化物组成。过渡层由马氏体及弥散分布的碳化物和残留奥氏体组成。在扫描速度和离焦量一定的条件下,相变硬化层深度随光纤激光功率的增大而增加。在最佳工艺(光纤激光功率900W,扫描速度0.3m/s,离焦量-4mm)条件下,硬化层平均硬度达609HV。分析认为光纤激光淬火造成的组织细化和过饱和的隐晶马氏体的形成是硬度提高的主要原因。 相似文献
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利用区熔定向凝固设备制备了Tb0.3Dy0.7Fe1.95合金,研究了不同定向凝固生长速度下Tb0.3Dy0.7Fe1.95合金的轴向择优取向、晶体的生长方式、结晶形貌的变化规律以及它们之间的关系。结果表明,随着定向凝固生长速度V从低速10μm/s逐步增大到380μm/s,Tb0.3Dy0.7Fe1.95合金的轴向择优取向从〈110〉方向转变为〈311〉及〈110〉、〈211〉、〈533〉多种混合轴向取向,之后又转变为原来的〈110〉方向,当V≥350μm/s后,轴向择优取向变得不明显。在整个过程中出现了2个不稳定过渡阶段,即180μm/s相似文献
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Zhengfen Wan;Zichen Liu;Qiwen Zhang;Qiming Zhang;Min Gu; 《Advanced Materials Technologies》2024,9(10):2302033
Perovskite has attracted considerable attention in the electronic and optical fields in recent years, fulfilling the requirements of the ever-growing demand in energy, environment, security, and big data storage. Laser direct writing technology is a flexible and mask-free approach for fabricating, structuring, modifying, and patterning perovskites. Laser irradiation can directly induce perovskites from precursors due to the photothermal and photochemical effects of laser. Therefore, various laser-induced perovskites, such as perovskite quantum dots, nanowires, nanocrystals, and films, are summarized. In particular, the laser-induced perovskites in glass are intensively investigated for their high stability and flexibility in 3D printing. The second part of this review examines various applications of perovskites based on laser technology, such as solar cells, flat lenses, microlasers, photoluminescence, lithography, sensors, optical encryption, and data storage. Diverse laser treatments employed for modulating and patterning perovskite devices, such as laser annealing, laser ablation, and laser-induced defects, are discussed. Prospective challenges and future trends in this research field are also concluded. 相似文献
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Xuefei Wu;Han Xue;Gautam Bordia;Zachary Fink;Paul Y. Kim;Robert Streubel;Jiale Han;Brett A. Helms;Paul D. Ashby;Ahmad K. Omar;Thomas P. Russell; 《Advanced materials (Deerfield Beach, Fla.)》2024,36(19):2310435
An active droplet system, programmed to repeatedly move autonomously at a specific velocity in a well-defined direction, is demonstrated. Coulombic energy is stored in oversaturated interfacial assemblies of charged nanoparticle-surfactants by an applied DC electric field and can be released on demand. Spontaneous emulsification is suppressed by an increase in the stiffness of the oversaturated assemblies. Rapidly removing the field releases the stored energy in an explosive event that propels the droplet, where thousands of charged microdroplets are ballistically ejected from the surface of the parent droplet. The ejection is made directional by a symmetry breaking of the interfacial assembly, and the combined interaction force of the microdroplet plume on one side of the droplet propels the droplet distances tens of times its size, making the droplet active. The propulsion is autonomous, repeatable, and agnostic to the chemical composition of the nanoparticles. The symmetry-breaking in the nanoparticle assembly controls the microdroplet velocity and direction of propulsion. This mechanism of droplet propulsion will advance soft micro-robotics, establishes a new type of active matter, and introduces new vehicles for compartmentalized delivery. 相似文献
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利用对40Cr钢与Cr12MoV钢分别进行表面激光淬火预处理后进行固态焊接试验,探讨了焊接工艺参数（焊接温度、焊接时间、应变速率、保温过程等因素）对焊接质量的影响。焊接温度过低,拉伸强度不高,但焊接温度太高材料抗氧化性下降,同时对提高生产率、节能降耗产生不利影响。焊接时间过长,晶粒长大,接头强度降低。表面激光淬火使表层组织显著细化,超塑性机制得到充分发挥。试验结果表明：预压应力为56．6MPa,加热温度为800℃,焊接时间为5min,保温时间为10min可达到高质量的固相焊接。 相似文献
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Yanlei Hu Hongwei Yuan Shunli Liu Jincheng Ni Zhaoxin Lao Chen Xin Deng Pan Yiyuan Zhang Wulin Zhu Jiawen Li Dong Wu Jiaru Chu 《Advanced materials (Deerfield Beach, Fla.)》2020,32(31):2002356
Artificial microstructures composed of chiral building blocks are of great significance in the fields of optics and mechanics. Here, it is shown that highly ordered chiral structures can be spontaneously assembled by a meniscus-directed capillary force arising in an evaporating liquid. The chirality is facilitated by rationally breaking the intrinsic symmetry in the unit cells through cooperative control of the geometry and spatial topology of the micropillars. The interfacial dynamics of the assembly process are studied to show that the sequential self-organization of the micropillars is influenced by the geometries, stiffness, and spatial arrangements. A diversity of chiral assemblies with controlled handedness is yielded by varying the pillar number, height, cross-section, laser power, and spatial topology. Lastly, the differential reflectance of light carrying opposite orbital angular momentums on the assembled chiral architectures are investigated, showcasing their potential in the field of chiral photonics concerning enantioselective response and exceptional optical functions. 相似文献
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超高温氧化物共晶陶瓷具有优异的高温强度、高温蠕变性能、高温结构稳定性以及良好的高温抗氧化和抗腐蚀性能, 成为1400 ℃以上高温氧化环境下长期服役的新型候选超高温结构材料之一, 在新一代航空航天高端装备热结构部件中具有重要的应用前景。基于熔体生长技术, 以选择性激光熔化和激光定性能量沉积为代表的激光增材制造技术具有一步快速近净成形大尺寸、复杂形状构件的独特优势, 近年来已发展成为制备高性能氧化物共晶陶瓷最具潜力的前沿技术。本文从工作原理、成形特点、技术分类等方面概述了基于熔体生长的两种典型激光增材制造技术, 综述了激光增材制造技术在超高温氧化物共晶陶瓷制备领域的研究现状和特点优势, 重点介绍了选择性激光熔化和激光定向能量沉积超高温氧化物共晶陶瓷在激光成形工艺、凝固缺陷控制、凝固组织演化、力学性能等方面的研究进展。最后, 指出了实现氧化物共晶陶瓷激光增材制造工程化应用亟需突破的关键瓶颈, 并对该领域未来的重点发展方向进行了展望。 相似文献
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回火工艺对4Cr13钢激光淬火组织及耐蚀性的影响 总被引：1，自引：0，他引：1
研究了４Ｃｒ１３钢表面激淬火及续回火的组织及耐蚀性。结果表明，快速加热激光淬火抑制了碳、铬元素的充分扩散。导致未溶碳化物与周围基体之间碳、铬浓度差减少、使钝化区间变宽。经回火处理后蚀性明显变差。这种变化的程度与回火时碳原子的偏聚及碳化物析出的数量、大小密切相关。 相似文献