近红外光热转换纳米晶研究进展

近红外光热转换纳米晶材料因其在近红外区(普遍位于780~1 400 nm)的高效光热转换性能,已广泛应用于光热杀死癌细胞、肿瘤治疗、海水淡化等领域。因其多样的液相制备方法和形貌控制、纳米结构复合、逐渐提高的光热转换效率以及表面易于药物修饰等优点,该材料在光热成像诊断、光热治疗等领域引起了学术界的广泛关注。本文综述了近红外光热转换纳米晶的研究进展,主要包括贵金属纳米晶、铜硫族半导体纳米晶、碳相关纳米晶以及这些纳米晶材料构成的复合结构,同时介绍了具有较高光热转换效率的表面等离子体共振(SPR)材料的研究进展,尤其是双模态SPR性质的耦合在光热转换领域的应用前景。基于其性能协同耦合的特性,双模态表面等离子体共振耦合的复合纳米晶将是近几年光热转换纳米晶发展的重要方向。     

亲水表面金纳米流体液滴光热蒸发特性研究

金纳米颗粒在可见光区具有高消光效率引起科研人员关注。金纳米流体被用作太阳能体吸收工质。通过太阳能加热亲水表面金纳米流体液滴蒸发实验,详细研究了液滴蒸发过程特性。液滴蒸发过程中液滴几何参数和表面温度被仪器实时记录。液滴蒸发主要为常接触面积模式,接触角逐渐减小。液滴体积随时间线性变化,与传统理论蒸汽扩散模型结果不同。本文研究能帮助指导太阳能光热利用以及液滴蒸发在工业中的应用。     

芯帽纳米颗粒的光热性质

贵金属纳米结构中的光热效应在肿瘤光热治疗、光热成像、纳米药物等领域具有重要的应用价值.各向异性的芯帽纳米结构以其丰富的可调结构参数和对激发光偏振态敏感的特性,可灵活地在近红外波段获得理想的光学吸收性质,从而可以实现温度的高效调节.本文基于有限元方法研究了颗粒物纳米结构参数对其光热效果的作用规律,数值结果表明:通过对结构参数的微量改变(包括金壳厚度、芯壳比、芯径、金属表面覆盖率等)可实现温度的显著调整;在偏振态的旋转范围(30?—70?)内可快速地产生大温变光热的准线性调整.其不弱于纳米芯壳和纳米棒结构的光热性能可为纳米光热生医研究提供一种新的选择.     

金纳米星诊疗剂的光热特性及其在光热治疗和光学相干层析成像中的应用研究

为了开发一种优异的用于光热治疗和光学相干层析成像的金纳米星诊疗剂,对金纳米星的制备、光热特性以及光热治疗和光学相干层析成像中的应用进行研究.利用尖端结构增强金纳米材料的局域表面等离子体共振特性,通过种子介导法制备了多枝化的金纳米星,多尖端的结构使其具有明显的光热效果,并探究了其作为光热治疗的诊疗剂和光学相干层析成像造影...     

抛物槽式太阳能集热器内合成油基纳米流体传热特性的数值模拟

对Al2O3-合成油纳米流体在槽式太阳能集热管内的传热特性进行流体动力学数值模拟,重点考察纳米流体导热系数模型的影响.通过与管内Nusselt数半经验模型的预测结果对比,表明使用考虑布朗运动的纳米流体导热系数模型可较好地预测集热管内传热特性.研究表明纳米颗粒与流体基液的相对运动具有促进集热管内传热的作用.最后,定量研究...     

光辐照精确调控金纳米星枝杈长度及其光热性能探究

金纳米星是一种具有尖状结构的多分枝纳米颗粒.为了使金纳米星枝杈长度可控,利用HEPES作为体系的还原剂、稳定剂及形状诱导剂,在制备过程中进行光辐照,得到的金纳米星枝杈长度比无光辐照时的金纳米星枝杈长度短,而且不同波长光辐照得到的金纳米星枝杈长度有显著不同.在此基础上,分析了金纳米星枝杈长度变化的物理过程,提出光诱导金纳米星生长过程中枝杈长度变化的理论模型.测量了不同枝杈长度的金纳米星在光辐照下一定时间内的温度变化,计算了金纳米星的光热转换效率.实验结果表明,光辐照制备金纳米星能够精确控制金纳米星枝杈长度范围,从而调控金纳米星的光热转换效率.     

纳米流体直接吸收式太阳能中温集热与热损分析

提出并探讨了导热油基液纳米流体为集热介质的太阳能直接吸收式集热方法用于中温热利用。在室外工况下,采用理论聚光比为5.2的槽式聚光器,对导热油-CuO纳米流体直接吸收式中温集热特性开展了实验测试,并与镀膜真空管集热性能进行了对比分析。实验结果显示,该纳米流体直接吸收式集热器的最大瞬时效率达70%,在150℃以下工况时的集热效率要高于传统镀膜吸收真空集热管;而当集热温度升高至150℃以上,散热明显增大,集热效率降低。通过理论计算结合实验进行热损失分析,发现纳米流体直接吸收式集热过程中最大的热损失项为内管壁对外辐射散热,约占总热损失的55%~70%。     

二氧化钛纳米流体的固液相变特性

采用“两步法”制备出不同浓度的TiO2-H2O纳米流体,选用紫外分光光度法对纳米流体的分散稳定性进行了评价,使用差示扫描量热仪对纳米流体以及基液一去离子水的固液相变过程进行了测试。实验结果表明：纳米流体的分散稳定性随着TiO2粒子质量浓度的增大先增强后减弱;添加纳米颗粒可以促进去离子水的异质成核,减小其固液相变过冷度;...     

纳米尺度下光热治疗等离激元耦合影响分析

作为一种高效、 局域化且高度可控的纳米热源, 金纳米棒越来越多的应用于肿瘤的光热治疗之中。 为探讨微观尺度下金纳米棒的产热与传热机理, 以及颗粒之间耦合作用对体系光热效应的影响。 本文运用基于有限元的 COMSOL 软件, 建立了金纳米棒光热耦合的三维模型, 分析了排布方式和颗粒间距等因素对纳米棒光学性质和光热响应的影响。 研究表明, 不同排布方式下近距离耦合颗粒之间的耦合强度随间距的增大呈指数衰减, 在一定间距范围内这种衰减行为可以被等离子体尺度方程描述; 单体共振波长照射下, 颗粒间的聚集影响光热治疗的效果, 在颗粒耦合作用范围内, 分散性越高, 体系加热效果越好。 本文研究模型及所得结论可为金纳米棒的产热与传热机理及肿瘤的光热治疗提供参考与指导。     

ZnO纳米流体对氨水降膜吸收影响的实验研究

通过配制不同浓度ZnO纳米流体的氨水溶液,研究了ZnO纳米流体氨溶液在降膜吸收器内定初始压力条件下对氨气的吸收效果。结果表明:不同浓度的纳米流体体现出对氨水降膜吸收强化的效果有所不同,随着ZnO纳米流体浓度的增大,对氨水降膜吸收的强化影响先增大后减小,且在浓度为0.1wt%时强化效果最佳。从实验还可看出,氨水基液浓度的增加使氨气的吸收量逐渐减小,但纳米流体的添加均可使吸收量得到不同程度的提高,纳米流体的加入,还可放缓由于氨水基液浓度增高引起的吸收速率降低的速度,且强化吸收的最佳纳米流体浓度不随氨水基液浓度的改变而改变。     

Mitochondria-Targeted Bovine Serum Albumin@Copper Sulfide Nanocomposites Conjugated with Rhodamine-110 Dye for an Enhanced Efficacy of Cancer Photothermal Therapy

Recently, mitochondria-targeted photothermal nanoagents demonstrated an improved therapeutic efficacy of cancer cells, compared with non-targeting ones. Herein, copper sulfide (CuS) nanoparticles are in situ synthesized via bovine serum albumin (BSA) templates to prepare photothermal BSA@CuS nanocomposites with high efficiency (42.0%) of photothermal conversion. Subsequently, rhodamine-110 (R) molecules are covalently conjugated with BSA@CuS nanocomposites to construct mitochondria-targeted R-BSA@CuS nanocomposites, which still retained 22.8% of photothermal conversion efficiency. Furthermore, as-prepared R-BSA@CuS nanocomposites can be efficiently internalized by human breast cancer (MCF-7) cells, and then specifically accumulated in their subcellular mitochondria, not lysosomes. Compared with non-targeting BSA@CuS nanocomposites, these mitochondria-targeted R-BSA@CuS nanocomposites show a significant enhancement (***p < 0.001) of their anticancer efficacy under the same near-infrared irradiation conditions, whose mechanism is further explored in details. Finally, these R-BSA@CuS nanocomposites can succeed in penetrating in 3D multicellular tumor spheroids composed of MCF-7 cells. And they also show a significant inhibition effect (**p < 0.01) on the growth of spheroids via photothermal therapy, in contrast to bare BSA@CuS nanocomposites under the same irradiation conditions. Therefore, these mitochondria-targeted and photothermal R-BSA@CuS nanocomposites have important potential applications on cancer photothermal therapy with an enhanced efficacy.     

Highly Ligand‐Directed and Size‐Dependent Photothermal Properties of Magnetite Particles

The development of cancer photothermal therapies, many of which rely on photothermal agents, has received significant attention in recent years. In this work, various ligands‐stabilized magnetite (Fe₃O₄) particles are fabricated and utilized as a photothermal agents for in vivo tumor‐imaging‐guided photothermal therapy. Fe₃O₄ particles stabilized by macromolecular ligands as, e.g. polyethylene glycol (PEG), exhibit a superior and more stable photothermal effect compared to Fe₃O₄ particles stabilized by small molecules like citrate, due to their stronger ability of antioxidation. In addition, the photothermal effect of Fe₃O₄ particles is revealed to increase with size, which is attributed to the redshift of Vis‐NIR spectra. Fe₃O₄ particles injected intravenously into mice can be accumulated in the tumor by the application of an external magnetic field, as revealed by magnetic resonance imaging. In vivo photothermal therapy test of PEG‐stabilized Fe₃O₄ further achieves better tumor ablation effect. Overall, this study demonstrates efficient imaging‐guided photothermal therapy of cancer that is based on Fe₃O₄ particles of optimized size and with optimized ligands. It is expected that the ligand‐directed and size‐dependent photothermal effect will provide more approaches in the design of novel materials.     

Facile Synthesis of Manganese Tellurite Nanoparticles for Magnetic Resonance Imaging-Guided Photothermal Therapy

In this study, manganese tellurite (MnTeO₃) nanoparticles are developed as theranostic agents for magnetic resonance imaging (MRI)-guided photothermal therapy of tumor. MnTeO₃ nanoparticles are synthesized via a simple one-step method. The as-synthesized MnTeO₃ nanoparticles with uniform size show good biocompatibility. In particular, MnTeO₃ nanoparticles exhibit a high photothermal conversion efficiency (η = 26.3%), which is higher than that of gold nanorods. Moreover, MnTeO₃ nanoparticles also have high MRI performance. The longitudinal relaxivity (r₁) value of MnTeO₃ nanoparticles is determined to be 8.08 ± 0.2 mm ⁻¹ s⁻¹, which is higher than that of clinically approved T₁-contrast agents Gd-DTPA (4.49 ± 0.1 mm ⁻¹ s⁻¹). The subsequent MnTeO₃ nanoparticles-mediated photothermal therapy displays a highly efficient ablation of tumor cells both in vitro and in vivo with negligible toxicity. It is demonstrated that MnTeO₃ nanoparticles can serve as promising theranostic agents with great potentials for MRI-guided photothermal therapy.     

Dye-sensitized solar cell module realized photovoltaic and photothermal highly efficient conversion via three-dimensional printing technology

Three-dimensional(3D) printing technology is employed to improve the photovoltaic and photothermal conversion efficiency of dye-sensitized solar cell(DSC) module. The 3D-printed concentrator is optically designed and improves the photovoltaic efficiency of the DSC module from 5.48% to 7.03%. Additionally, with the 3D-printed microfluidic device serving as water cooling, the temperature of the DSC can be effectively controlled, which is beneficial for keeping a high photovoltaic conversion efficiency for DSC module. Moreover, the 3D-printed microfluidic device can realize photothermal conversion with an instantaneous photothermal efficiency of 42.1%. The integrated device realizes a total photovoltaic and photothermal conversion efficiency of 49% at the optimal working condition.     

原子吸收法测定枸杞子矿物质元素的三种前处理方法比较

采用干灰化法、HNO₃-H₂O₂湿法消解法和HNO₃-HClO₄湿法消解法分别处理枸杞子样品,利用原子吸收光谱法测定各组样品中Na,K,Ca,Mg,Fe,Cu,Zn,Ni,Pb,Cd十种元素的含量,探讨简单、快捷、准确地测定枸杞子中矿物质元素的前处理方法。结果表明：干灰化法的回收率范围为89.88%～102.15%,标准偏差(RSD)<3.037% ;HNO₃-H₂O₂湿法消解法的回收率范围为92.34%～103.21%,标准偏差(RSD)<2.751%;HNO₃-HClO₄湿法消解法的回收率范围为94.52%～102.10%,标准偏差(RSD)<2.496%;三种方法均具有较好的准确度和精密度,但相对于干灰化法和HNO₃-H₂O₂湿法消解法,HNO₃-HClO₄湿法消解法回收效果较好,精密度更高。HNO₃-HClO₄湿法消解法测得Na, K, Ca, Mg元素含量的平均值高于干灰化法和HNO₃-H₂O₂湿法消解法,差异有统计学意义(p<0.05)。此外,HNO₃-HClO₄体系湿法消解法耗时短、消耗试剂量少、消解完全。因而,HNO₃-HClO₄体系湿法消解法可作为原子吸收光谱法测定枸杞子矿物质元素含量较好的前处理方法。     

Polystyrene/Fe3O4 magnetic emulsion and nanocomposite prepared by ultrasonically initiated miniemulsion polymerization

Ultrasonically initiated miniemulsion polymerization of styrene in the presence of Fe3O4 nanoparticles was successfully employed to prepare polystyrene (PS)/Fe3O4 magnetic emulsion and nanocomposite. The effects of Fe3O4 nanoparticles on miniemulsion polymerization process, the structure, morphology and properties of PS/Fe3O4 nanocomposite were investigated. The increase in the amount of Fe3O4 nanoparticles drastically increases the polymerization rate due to that Fe3O4 nanoparticles increase the number of radicals and the cavitation bubbles. Polymerization kinetics of ultrasonically initiated miniemulsion polymerization is similar to that of conventional miniemulsion polymerization. PS/Fe3O4 magnetic emulsion consists of two types of particles: latex particles with Fe3O4 nanoparticles and latex particles with no encapsulated Fe3O4 nanoparticles. Fe3O4 nanoparticles lower the molecular weight of PS and broaden the molecular weight and particle size distribution. Thermal stability of PS/Fe3O4 nanocomposite increases with the increase in Fe3O4 content. PS/Fe3O4 emulsion and nanocomposite exhibit magnetic properties. PS/Fe3O4 magnetic particles can be separated from the magnetic emulsion by an external magnetic field and redispersed into the emulsion with agitation.     

A New Insight of the Photothermal Effect on the Highly Efficient Visible‐Light‐Driven Photocatalytic Performance of Novel‐Designed TiO2 Rambutan‐Like Microspheres Decorated by Au Nanorods

Photocatalyst‐assisted degradation of organic pollutants, which exhibits a novel strategy for solar‐energy utilization, possesses enormous potential in various applications. Extending the light‐absorption range in the spectrum of sunlight and improving light‐conversion efficiency are always primary issues to enhance the catalytic performance of these photocatalysts. Herein, a new structure of gold‐nanorod‐decorated TiO₂ rambutan‐like microspheres is designed, which exhibits superior photocatalytic ability toward Rhodamine B in the range of visible light due to the 3D distribution of the TiO₂ branches on the surface of the microspheres, which prompts the multireflection of photons. The absorption rate of photons is thereby tremendously enhanced. This is beneficial for the generation of hot electrons originating from the localized surface plasmonic resonance of Au nanorods, which can be used to both initiate the reaction and produce the photothermal effect. Hot electrons generated by a single Au nanorod in microspheres to initiate the degradation reaction can be as high as 2.5 times of those in the nanowires' counterpart. Moreover, the heating power of a single Au nanorod in microspheres reaches up to 4.4 times higher than that in nanowires, which further accelerates the degradation rate. The reaction pathway of visible‐light‐assisted RhB degradation catalyzed by Au/TiO₂ microspheres goes through an initial N‐deethylation process instead of the complete cycloreversion catalyzed by pure TiO₂ microspheres under UV irradiation. This strategy of structure design for improved photon absorption, which achieves high degradation rate and photothermal effect, is promising for the development of novel photocatalysts.     

磁性纳米TiO_2/Fe_3O_4的制备及其光催化性能

采用特殊液相沉淀法分两步制备了壳核结构的磁性纳米TiO2/Fe3O4,并讨论了TiO2/Fe3O4比例对其磁性的影响。利用XRD、TEM和VSM对其进行了表征,用它做催化剂,甲基橙溶液为降解目标,在日光作用下对其光催化活性进行了研究,并测出了其回收率。结果表明,在本实验条件下制备的磁性纳米TiO2/Fe3O4表现为超顺磁性,具有较强的光催化活性和较高的回收率。当TiO2∶Fe3O4为4∶1,在450℃焙烧30min条件下得到的催化剂,对20mg/L的甲基橙溶液在60min内降解率高达91.5%,明显高于纯TiO2的催化活性,在外加强磁场的作用下,此催化剂很快从溶液中分离出来,测得其回收率为88.2%。     

光学薄膜热膨胀系数的研究

光热位移偏转技术结合横向光热偏转技术可用于研究薄膜样品的热膨胀系数.本文以SiO_2、TiO_2、ZrO_2、MgF_2、ThF4等单层光学薄膜为例.报道相关的实验方法及实验结果.