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There is an increasing demand for advanced optical imaging techniques that can detect and resolve nanosize objects at a spatial resolution below the optical diffraction limit,especially in three-dimensional (3D) cellular environments.In this study,using a polarization-activated localization scheme based on the orientation-dependent properties of anisotropic plasmonic metal nanoparticles (MNPs),"photoswitchable" imaging of single gold nanorods (AuNRs) was accomplished not only in two dimensions but also in three dimensions.Moreover,the Rayleigh scattering background arising from the congested subcellular structures was efficiently suppressed.Thus,we obtained the 3D distributions of both the position and the orientation of the AuNRs inside the cells and investigated their internalization kinetics.To our knowledge,this is the first demonstration of the confocal-like 3D imaging of non-fluorescence nanoparticles with a high resolution and almost zero background.This technique is easy to implement and should greatly facilitate MNP studies and applications in biomedicine and biology. 相似文献
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本文综述了磁电阻 (MR)材料的研究进展 ,并对目前研究热点的四类巨磁电阻 (GMR)材料进行了概括评述 ,侧重论述MR材料在信息存储等领域的应用 ,明确指出开发和应用MR材料的关键问题是提高各类GMR材料的室温MR值和降低其工作磁场 相似文献
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城市污水厂污泥改性物对Hg(Ⅱ)吸附的研究 总被引:1,自引:0,他引:1
以城市污水处理厂活性污泥为原料,制取干污泥,并将其和化学改性污泥作为吸附剂,对含Hg(Ⅱ)离子的废水进行了吸附试验研究.考察了溶液pH值、吸附剂用量和Hg(Ⅱ)离子的初始浓度对去除率的影响.结果表明,干污泥及其化学改性污泥吸附剂对Hg(Ⅱ)离子的吸附符合Lagergren一级动力学方程.在试验条件下,化学改性污泥的相对吸附量高于干污泥,因此,活性污泥经过化学改性后能够提高对Hg(Ⅱ)离子的吸附能力.用0.1mol/L HNO3溶液进行超声解吸附,Hg(Ⅱ)离子的回收率可达70%左右.利用这种吸附剂可以有效地去除工业废水中的Hg(Ⅱ)离子. 相似文献
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Smart‐Dust‐Nanorice for Enhancement of Endogenous Raman Signal,Contrast in Photoacoustic Imaging,and T2‐Shortening in Magnetic Resonance Imaging 下载免费PDF全文
Christoph Pohling Jos L. Campbell Timothy A. Larson Dominique Van de Sompel Jelena Levi Sanjiv S. Gambhir 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(19)
Raman microspectroscopy provides chemo‐selective image contrast, sub‐micrometer resolution, and multiplexing capabilities. However, it suffers from weak signals resulting in image‐acquisition times of up to several hours. Surface‐enhanced Raman scattering (SERS) can dramatically enhance signals of molecules in close vicinity of metallic surfaces and overcome this limitation. Multimodal, SERS‐active nanoparticles are usually labeled with Raman marker molecules, limiting SERS to the coating material. In order to realize multimodal imaging while acquiring the rich endogenous vibronic information of the specimen, a core–shell particle based on “Nanorice”, where a spindle‐shaped iron oxide core is encapsulated by a closed gold shell, is developed. An ultrathin layer of silica prevents agglomeration and unwanted chemical interaction with the specimen. This approach provides Raman signal enhancement due to plasmon resonance effects of the shell while the optical absorption in the near‐infrared spectral region provides contrast in photoacoustic tomography. Finally, T2‐relaxation of a magnetic resonance imaging (MRI) experiment is altered by taking advantage of the iron oxide core. The feasibility for Raman imaging is evaluated by nearfield simulations and experimental studies on the primate cell line COS1. MRI and photoacoustics are demonstrated in agarose phantoms illustrating the promising translational nature of this strategy for clinical applications in radiology. 相似文献
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本文简要回顾了储氢材料研究的发展情况 ,主要介绍了纳米碳管储氢的实验进展。作者对纳米碳管储氢的机理方面进行了初步探讨 ,针对单壁纳米碳管 ,提出了一种解离凝聚机制 相似文献
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日本关于超细晶粒钢制备与焊接新工艺的研究进展 总被引:5,自引:0,他引:5
介绍了日本3家公司的3种不同超细晶粒钢制备工艺,以及两项于2002年获得日本溶接学会奖励的超细晶粒钢焊接新技术. 相似文献
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铀钚金属表面抗腐蚀性研究进展 总被引:2,自引:0,他引:2
金属铀钚表面的腐蚀与防腐蚀一直受到关注,章综述了自1994年来作实验室在铀钚金属表面抗腐蚀性方面的研究进展。用X射线光电子能谱(XPS)、气相色谱(GC)等方法系统地分析研究了金属铀和U3O8与CO、CO2、H2等气体的相容性及其表面化学行为,铀试样在CO气氛中的贮存氧化增重及δ-Pu金属和铀试样在该气氛贮存期气相组成变化;应用改进的量子力学计算方法对金属铀钚化合物的分子结构、势能函数、光谱性质、热力学性质和动力学性质进行了系统研究;应用热力学平衡原理方法研究了铀和钚在还原气氛中的表面化学反应。通过实验与理论结合的系统研究,揭示了铀与上述气体介质相互作用的规律,得到一系列具有实际应用和理论意义的实验研究和理论计算结果,为进一步深化铀钚金属抗腐蚀研究奠定了基础。研究结果表明CO的存在有利于抑制铀钚金属的表面氧化腐蚀。 相似文献
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Sm2(Fe,M)17Nx稀土永磁材料的研究进展 总被引:2,自引:0,他引:2
概述了Sm2(Fe,M)17Nx稀土永磁体,详细论述了磁性能及其影响因素,着重强调了成为新一代实用永磁体的巨大力,并展望了未来发展趋势。 相似文献
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运用功能磁共振成像(fMRI)技术,采用适合中国人情绪加工特点的表情图片(愉快、悲伤和中性表情)作为刺激材料,选取15名严格入组的未服药单相抑郁症女性患者与15名条件匹配的正常志愿者,对其情绪加工的大脑活动进行了对比研究。结果发现,与中性表情相比,在加工愉快表情时,抑郁症患者激活了右侧前额叶,而正常对照组激活的是左侧前额叶;在悲伤表情条件下,抑郁症患者激活了双侧颞下回,而正常对照组激活的是双侧前额叶。结果还发现,与正常对照组相比,抑郁症患者在双侧额下回三角区、右侧眶额下回、右侧颞下回等脑区的激活范围和强度均有所减少,尤其在加工悲伤表情时表现得更明显。该结果表明,单相抑郁症病人不仅在情绪加工相关脑区的功能上出现异常,而且加工情绪的脑区也可能出现了转移。 相似文献
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近年来,数字成像技术不断提高和应用范围的迅速推广,也推动了UV固化技术在这一领域的融合和应用,取得了极大的成效,由于UV固化材料具有快速固化、高效、低污染、节能、优质等特点,很快发展成为一种新型的数字成像材料。目前实现产业化的主要有UV喷墨打印、印刷电路版数字化制作、计算机直接制版CTP、立体光刻等四种技术,作者拟分为四个专题予以阐述,本文主要讨论其第三个专题:UV固化技术在计算机直接制版(CTP)中的应用。 相似文献
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Dual‐Modality Surface‐Enhanced Resonance Raman Scattering and Multispectral Optoacoustic Tomography Nanoparticle Approach for Brain Tumor Delineation 下载免费PDF全文
Difficulty in visualizing glioma margins intraoperatively remains a major issue in the achievement of gross total tumor resection and, thus, better clinical outcome of glioblastoma (GBM) patients. Here, the potential of a new combined optical + optoacoustic imaging method for intraoperative brain tumor delineation is investigated. A strategy using a newly developed gold nanostar synthesis method, Raman reporter chemistry, and silication method to produce dual‐modality contrast agents for combined surface‐enhanced resonance Raman scattering (SERRS) and multispectral optoacoustic tomography (MSOT) imaging is devised. Following intravenous injection of the SERRS‐MSOT‐nanostars in brain tumor bearing mice, sequential MSOT imaging is performed in vivo and followed by Raman imaging. MSOT is able to accurately depict GBMs three‐dimensionally with high specificity. The MSOT signal is found to correlate well with the SERRS images. Because SERRS enables uniquely sensitive high‐resolution surface detection, it could represent an ideal complementary imaging modality to MSOT, which enables real‐time, deep tissue imaging in 3D. This dual‐modality SERRS‐MSOT‐nanostar contrast agent reported here is shown to enable high precision depiction of the extent of infiltrating GBMs by Raman‐ and MSOT imaging in a clinically relevant murine GBM model and could pave new ways for improved image‐guided resection of brain tumors. 相似文献
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P. Allan‐Wojtas C. F. Forney L. Moyls D. L. Moreau 《Packaging Technology and Science》2008,21(4):217-229
Bright field transmitted light microscopy (BFTLM), differential interference contrast light microscopy (DICLM), conventional scanning electron microscopy (SEM) and low‐vacuum scanning electron microscopy (LV‐SEM) were used to observe microperforations in plastic film used for modified atmosphere packaging. Characteristics of the microperforations, including size, shape and obstructions are indicators of consistency and reproducibility of the process used to produce the microperforations. In addition, the microperforations appeared differently on the upper and lower surfaces of the plastic films, including a local thickening at the site of the microperforation and size of the opening. Microperforations in the range of 30 to 100 µm in diameter exhibited a linear increase of both O2 and CO2 transmission rates with hole area, for diffusion under calm conditions. Further testing indicated that microperforations larger than 55 µm in diameter can lose their diffusion constant if convection is present. Holes with a diameter less than 55 µm should therefore be used to achieve the required oxygen transmission rates (OTR). Copyright © 2007 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. 相似文献