Hydrophilic bismuth sulfur nanoflower superstructures with an improved photothermal efficiency for ablation of cancer cells

Nanomaterials with intense near-infrared (NIR) absorption exhibit effective photon-to-thermal energy transfer capabilities and can generate heat to ablate cancer cells, thus playing a pivotal role in photothermal cancer therapeutics. Herein, hydrophilic flower-like bismuth sulfur (Bi₂S₃) superstructures with uniform size and improved NIR absorption were controllably synthesized via a facile solvothermal procedure assisted by polyvinylpyrrolidone (PVP), which could adjust the product morphology. Induced by an 808-nm laser, the as-prepared Bi₂S₃ nanoflowers exhibited much higher photothermal conversion efficiency (64.3%) than that of Bi₂S₃ nanobelts (36.5%) prepared in the absence of PVP. This can be attributed not only to the Bi₂S₃ nanoflower superstructures assembled by 3-dimensional crumpled-paper-like nanosheets serving as many laser-cavity mirrors with improved reflectivity and absorption of NIR light but also to the amorphous structures with a lower band gap. Thus, to achieve the same temperature increase, the concentration or laser power density could be greatly reduced when using Bi₂S₃ nanoflowers compared to when using Bi₂S₃ nanobelts, which makes them more favorable for use in therapy due to decreased toxicity. Furthermore, these Bi₂S₃ nanoflowers effectively achieved photothermal ablation of cancer cells in vitro and in vivo. These results not only supported the Bi₂S₃ nanoflowers as a promising photothermal agent for cancer therapy but also paved an approach to exploit new agents with improved photothermal efficiency.

Open image in new window

     

High energy-storage density under low electric fields and improved optical transparency in novel sodium bismuth titanate-based lead-free ceramics

A novel (1-x)Na_0.5Bi_0.5TiO₃-xBaHfO₃ (abbreviated as (1-x)NBT-xBH) transparent ceramic was fabricated by the solid state reaction method. X-ray diffraction analysis showed that NBT-based transparent ceramics exhibit a cubic-like perovskite structure and the solid solubility of BH in NBT reached to 0.15. The Landau-Devonshire theory and I-E curves revealed that the transition between the antiferroelectric like phase and the ferroelectric phase deeply relies on the variation of composition and free energy. One sample (x = 0.15) was found to show a high dielectric constant (˜2418±10%) over the temperature range 57–400 °C. These ceramics also exhibited a high discharge energy density (W_d) of 2.1 J/cm³ and a high maximum polarization P_m of 34 μC/cm² under relatively low electric fields which were less than 175 kV/cm. There was also high transparency in the visible spectra (more than 0.5) when the sample thickness was 250 μm.     

(Na_(1/2)Bi_(1/2))TiO_3-SrTiO_3无铅压电陶瓷的介电、压电性能

研究了 (Na1 / 2 Bi1 / 2 ) Ti O3- Sr Ti O3二元系无铅压电陶瓷的介电、压电性性。Sr2 的引入对 NBT材料的常温介电系数、铁电相与反铁电相转变温度 TF A(180°C)以及居里温度 TC(30 0°C)的影响都不大 ,但却较大幅度地降低了 NBT材料的高矫顽场 ,从而使极化相对容易。(Na1 / 2 Bi1 / 2 ) Ti O3- Sr Ti O3二元系的压电性能参数 d33和 kt分别达到 10 0 p C/N和 0 .45     

中国铋供需形势分析及对策建议

铋(Bismuth)是全球公认的一种可安全使用的"绿色金属"。目前,铋广泛应用于氧化铋行业、医药行业、铋合金及焊料和冶金添加剂等领域。中国是全球最大的铋资源国、生产国、消费国和出口国,但不是铋产业强国,因此及时认清当前中国铋的供需形势,是国家和企业制定发展战略的基础。本文在全球视野下,首先对中国铋的资源状况、生产供应、需求现状、贸易等进行综合分析,然后结合中国铋未来发展趋势,作出了2030年左右中国铋的需求量将达到峰值18000t的判断。文章最后针对中国铋产业面临的突出问题,分别从资源开发、资源回收、技术提高和降低国际市场风险等方面提出了中国铋产业健康发展的对策建议。     

氯氧铋湿法还原制备海绵铋的研究

研究了氯氧铋湿法还原制备海绵铋的方法。将氯氧铋置于盐酸溶液中搅拌溶解,溶解过程中加入铁粉还原铋离子,最后得到铋含量80%左右的海绵铋。研究了盐酸浓度、液固比、铁粉加入前反应时间、铁粉用量、铁粉加入后反应时间、反应温度对铋还原效果的影响,得出反应最佳条件为:盐酸浓度2.5 mol/L、液固比5∶1、铁粉加入前反应时间0.5 h、铁粉用量为理论量1.25倍、铁粉加入后反应时间3 h、反应温度常温,此时海绵铋中铋含量为84.93%。     

高电位CuV_2O_6正极材料在热电池中的应用

采用固相法以CuO粉末和V2O5粉末为原料制备α-CuV2O6粉末,用X射线衍射分析(XRD)、差热分析(DTA)和粒度分析方法对铜钒氧材料进行了表征,并对其作为热电池正极材料的电化学行为进行了研究。电化学性能测试表明,制备的α-CuV2O6电极单体电池具有较高的放电电压和较大的放电比容量。     

Texture prediction of Bi2Te3 electroplated layers using Hartman's theory of crystal growth

An experimental study of electroplated thin films of bismuth telluride, R3m crystal structure, shows that fibre textures are observed during the growth of the layers. Several orientations 00.1, 10.10, 11.0, 10.4, 10.8, 01.5 and 10.0 are developed during the deposition process, then reach a final orientation. Hartman's theory of crystal growth based on the periodic bond chain (PBC) in a crystal lattice is usually applied. This explains the equilibrium shape of a crystal defined by F faces and the faces observed during the growth (S and K faces). It also successfully predicts the orientations observed in bismuth telluride from the beginning to the end of the layer deposition. The theory may also be applied to other deposition processes.     

用椰壳制活性炭吸附去除三价铋离子(英文)

In present study,we report the preparation of coconut shell activated carbon as adsorbent and its appli-cation for Bi(Ⅲ) removal from aqueous solutions.The developed adsorbent was characterized with scanning elec-tron microscope(SEM),Fourier Transform Infrared(FTIR),C,H,N,S analyzer,and BET surface area analyzer.The parameters examined include agitation time,initial concentration of Bi(Ⅲ),adsorbent dose and temperature.The maximum adsorption of Bi(Ⅲ)(98.72%) was observed at 250 mg·L-1 of Bi(Ⅲ) and adsorbent dose of 0.7 g when agitation was at 160 r·min-1 for 240 min at(299±2) K.The thermodynamic parameters such as Gibb’s free energy(△Gθ),enthalpy(△Hθ) and entropy(△Sθ) were evaluated.For the isotherm models applied to adsorption study,the Langmuir isotherm model fits better than the Freundlich isotherm.The maximum adsorption capacity from the Langmuir isotherm was 54.35 mg?g?1 of Bi(Ⅲ).The kinetic study of the adsorption shows that the pseudo second order model is more appropriate than the pseudo first order model.The result shows that,coconut shell ac-tivated carbon is an effective adsorbent to remove Bi(Ⅲ) from aqueous solutions with good adsorption capacity.     

铋掺杂对BST/MT复相铁电材料介电性能的影响

研究了Bi2O3掺杂对钛酸锶钡/钛酸镁(BST/MT)复合体系介电常数、介电损耗以及调谐性等介电性能的影响。实验表明,适量的掺杂能有效的改善体系的电性能。控制掺杂质量分数为0.8%,获得陶瓷介质在微波频段(S波段)的相对介电常数在100左右;介质损耗约为2×10-2;4 000 V/mm的偏压下调谐性可达12%。采用极化理论对掺杂机理作了一定的探讨。     

铁粉置换沉淀海绵铋的动力学研究

从动力学角度研究了铋湿法冶金中铁粉置换沉淀海绵铋的化学反应机理，探讨了Bi^3＋初始浓度、Cl^-浓度、温度、溶液pH及搅拌速率等因素对铋置换率的影响及动力学数学模型。通过测定不同温度条件下的表观反应速度常数（点），求得浸出反应活化能为14．61kJ／mol。试验结果表明，置换反应的所有动力学数据服从一级反应速率规律，置换过程符合扩散控制机理。