生物矿化及仿生矿化中的信息传递和转化

牙齿、骨骼、贝壳等生物矿物具有多级有序的结构和优异的力学性能,是生物矿化过程调控下的矿化结晶产物。生物矿化中的矿物与生物有机基质之间的界面分子识别和结晶调控策略为深入理解化学工程中的“信息传递和转化”范式提供了良好的学习素材。以生物矿化典型无机矿物磷酸钙和碳酸钙体系为例,从生物矿物-溶液界面结构、生物分子与矿物晶面的分子识别、矿物结晶调控三个层面综述了生物矿化的化学调控原理,并从信息传递和转化的化学工程范式出发,分析了生物矿化中分子工程和结晶调控策略。绿色高效的生物矿化过程调控策略有望应用于未来化学工程以解决目前面临的需求倍增和资源短缺的全球性问题。     

磁性纳米粒子的制备和包覆

磁性纳米粒子由于其广泛的应用一直以来都是研究的热点。随着合成技术的不断发展,各种磁性纳米粒子均已成功制得,特别是合成形貌可控,高度稳定和单分散性的磁性纳米粒子。综述了磁性纳米粒子的几种比较常见的合成方法及其包覆措施,并对磁性纳米材料的应用进行了展望。     

联氨还原法制备磁性钴纳米粒子

在表面活性剂聚乙烯吡咯烷酮(PVP)的保护下,采用水合肼于乙醇体系中还原CoCl2·6H2O而得到磁性钴纳米粒子,通过X射线衍射检验确认该种方法合成的钴纳米粒子同时具有hcp相和fcc相.X射线光电子能谱的表征结果显示钴粒子表面价态为零价,说明制备过程中没有被氧化.用透射电镜和激光光散射仪对粒子的表面形貌和粒径进行了表征分析,结果显示粒径在30nm左右,近似圆球形,在正己烷中分散效果较好.     

磁性纳米催化剂制备生物柴油研究进展

磁性纳米催化剂是一类具有磁响应特征的催化剂,由于具有较高的催化活性、良好的反应选择性及优良的磁响应性等优点,克服了纳米催化剂活性高但难分离的缺点,是生物柴油制备过程良好的甲酯化反应催化剂,为生物柴油催化剂研究的重要方向。本文综述了磁性纳米催化剂的结构特点、制备方法及其在制备生物柴油过程中的应用,并展望了其应用前景。     

磁性纳米催化剂的研究进展

介绍了磁性纳米催化剂的特性,综述了近年来磁性纳米催化剂在在氢化催化、加氢甲酰化催化、C-C键偶联反应催化、氧化和环氧化催化、酯化反应催化、缩合反应催化、烯烃复分解催化、光催化、生物催化等领域应用的研究进展,旨在探讨磁性纳米催化剂制备方法和应用领域,同时提出其应用过程中存在的问题,并对发展前景进行了展望。     

热分解法制备锰铁氧体磁性纳米粒子

以油酸为表面活性剂,1-十八烯为溶剂,通过高温热分解油酸铁和油酸锰制备了锰铁氧体磁性纳米粒子。考察了热分解温度和时间以及油酸与油酸盐的投料比对磁性纳米粒子结构和性质的影响。结果表明:随着反应温度的提高或反应时间的延长,所得磁性纳米粒子遵循α-Fe2O3-尖晶石结构锰铁氧体-锰铁氧化物固溶体的衍变过程,饱和磁强度也表现出先增强后减弱的规律。磁性纳米粒子形貌转变过程遵循粒子内熟化机理。随着反应时间延长,磁性纳米粒子由纺锤状纳米粒子转变为具有棱角的不规则状纳米粒子,进而形成球状磁性纳米粒子。当n(油酸)/n(油酸盐)=0.8,在300℃下热分解反应1 h时,磁性纳米粒子饱和磁强度达到15.14 emu/g。     

碳酸钙生物矿化研究

文章综述了有序分子模板对碳酸钙晶体的调控研究进展.研究结果表明,通过选择合适的实验条件,可以有效调控碳酸钙晶体的晶型、形貌、尺寸,这为生物矿化机理研究提供了一些依据,同时为合成新型材料提供了方法和途径.     

磁性纳米粒子/污泥基复合材料吸附性能研究进展

随着城市污水处理厂数量和规模的不断发展,污泥的处理与资源化利用成为环保领域的热点问题。制备磁性纳米粒子/污泥基复合材料处理水环境中的污染物是污泥资源化研究的重要方向之一,可达到污泥资源化利用及环境修复的双重目的。综述了磁性纳米粒子/污泥基复合材料的制备方法、吸附实验研究方法、吸附影响因素及吸附机理,并对磁性纳米粒子/污泥基复合材料的发展前景及研究方向进行了展望。     

新型磁性纳米级油酸改性铁氧磁流体磁性粒子的制备及表征

用油酸钠作为表面活性剂,采用化学共沉淀法制备纳米级油酸改性铁氧体磁性粒子,从温度T、碱的过量比y、表面活性剂的用量比n、反应时间t4个方面进行研究。确定高纯度、小粒径、强磁性、均匀分散的Fe3O4磁性粒子的合理工艺条件:t=180 min,T=80℃,y=0.25,n=0.6。红外光谱测试,证明产品为表面活性剂油酸包裹的纳米级磁性粒子,粒径<10 nm,XRD分析证实了产品为铁氧体磁性粒子,古埃磁天平对产品进行了性能测试。     

可生物降解纳米粒子制备研究进展

可生物降解纳米粒子作为纳米级药物载体，在蛋白质、多肽、疫苗、基因等药物控制释放方面具有广阔的应用前景。它的优点不仅在于其能有效地降低药物毒性，屏蔽药物不良气味并对药物控制释放，纳米粒子超微小的粒径能够有效地穿越组织间隙被细胞吸收，可通过人体的毛细血管甚至血脑屏障(BBB)来发挥药效。本文重点介绍近年来国内外可生物降解纳米粒子制备方法的进展情况，同时概述了各种影响因素和条件，并对可生物降解纳米粒子的发展做出展望。     

纳米银粒子制备及应用研究进展

综述了制备纳米银粒子的方法,主要包括液相化学还原法,电化学还原法、光化学还原法和分子自组装等,分析比较了这些方法的基本原理、制备过程及优缺点,阐述了纳米银粒子在化学反应,光学领域及抗菌等领域的应用.     

Research progress on magnetic nanoparticles for magnetic induction hyperthermia of malignant tumor

As a new malignant tumor therapy method with low side effect, high safety and efficiency, magnetic induction hyperthermia (MIH) has attracted great attention in recent years. As magnetic induction heating media, magnetic nanoparticles (MNPs) are critical for the development of MIH. For clinical safety, the MNPs need a high heating efficiency to reduce the applied dose, minimizing the risk of side effect. Increasing the saturation magnetization and initial susceptibility, adjusting the magnetocrystalline anisotropy constant and particle size to the optimal values are the effective methods of improving heating efficiency. On the other hand, a suitable Curie temperature is desired to realize the self-regulation of the therapy temperature, avoiding the use of clumsy and expensive temperature monitoring and control devices. Substituting the magnetic ions in tetrahedral (A) site of the spinel ferrite with nonmagnetic ions or magnetic ions with smaller magnetic moments can effectively reduce the superexchange interaction between the A and B (octahedral) sites, decreasing Curie temperature. Yet, the reduction of the Curie temperature by ion doping usually reduces the saturation magnetization, decreasing heating efficiency. Increasing the fraction of heat generated by relaxation loss and increasing the saturation magnetization may be used to improve the heating efficiency.     

Fe3O4水基磁流体的制备及其分散性能研究

采用共沉淀法制备了纯Fe3O4纳米粒子,分别用高氯酸、四甲基羟胺和油酸/十二烷基苯磺酸钠为表面活性剂对其进行表面处理后分散在水中,得到了3种水基磁流体,对这3种磁流体的浓度及稳定性进行了测定。实验结果显示:酸性、碱性和中性水基磁流体中Fe3O4的浓度分别为4.8%、5.8%和8.1%,其中中性水基磁流体中粒子的分散性能最佳;经过离心后,3种水基磁流体中的粒子均产生了沉降,且酸性和碱性磁流体中的粒子比中性磁流体中的粒子沉降的多。在此基础上,对影响粒子分散稳定性的机理进行了初步探讨。     

Effects of hydrothermal process parameters on the physical,magnetic and thermal properties of Zn0.3Fe2.7O4 nanoparticles for magnetic hyperthermia applications

Effects of hydrothermal temperature and time on physical, magnetic and thermal properties of Zn-substituted magnetite nanoparticles (Zn_0.3Fe_2.7O₄) were assessed. The magnetic nanoparticles were synthesized via citric acid-assisted hydrothermal reduction route at temperatures of 150, 175 and 200 °C for duration of 10, 15 and 20 h. The nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and specific loss power (SLP) measurements. The results showed that temperature and time of the hydrothermal process both had significant effects on nanoparticles composition and properties. It was observed that at 150 °C, heat generation was insufficient to produce activation energy required for nucleation of Zn_0.3Fe_2.7O₄ spinel nanoparticles, even after a long time. At 175 °C, although temperature was low, but the suitable condition for nucleation of nanoparticles was made and spinel nanoparticles with the size of about 13 nm were formed after 15 h. Nonetheless, since crystallinity and SLP of the nanoparticles was low, they showed weak performance for magnetic hyperthermia. At 200 °C, the required activation energy was provided for nanoparticles nucleation; however, the spinel was oxidized to hematite, resulting in a decrease in thermal and magnetic properties. In overall, the nanoparticles synthesized at 200 °C for 15 h possessed the best characteristics of reasonable purity, saturation magnetization of about 35.9 emu/g and SLP of 18.7 W/g.     

磁场诱导对AZ91D镁合金表面仿生矿化法制备羟基磷灰石涂层性能的影响

在无磁场及强度均为0.4 T的平行磁场和垂直磁场诱导下,采用仿生矿化法在AZ91D镁合金表面制备羟基磷灰石(HAP)涂层。采用扫描电镜、X射线衍射仪和测厚仪分析了HAP涂层的表面形貌、物相成分、晶体取向和厚度。结果表明,在垂直磁场条件下制备的HAP涂层最均匀、致密,晶体为a、b轴取向。     

单分散磁性Fe3O4纳米粒子的研究进展

具有良好的化学稳定性、生物相容性、磁响应性的单分散磁性Fe₃O₄纳米粒子,在药学、催化化学、医学和光电磁记录材料等方面都有很大的使用前景;而具有自组装光子晶体现象的Fe₃O₄磁性纳米粒子在包装、印刷、防伪等领域的应用中更展现出巨大的潜力。本文在对单分散磁性Fe₃O₄纳米粒子的制备方法进行了总结回顾,并对单分散磁性Fe₃O₄纳米粒子的光学应用领域做了简略的介绍,并对单分散磁性Fe₃O₄纳米粒子的发展趋向进行了展望,并总结分析现阶段大多数Fe₃O₄纳米粒子的合成方法在非极性溶液中分散性差,使其在实际应用中受到很大的限制,未来Fe₃O₄纳米粒子表面进行修饰将成为该领域的研究热点之一。     

反相微乳液法制备纳米颗粒研究进展

综述了反相微乳液的形成机理、配制方法和目前利用反相微乳液技术制备纳米颗粒方面的研究进展，并对微乳液的配制及制备过程中影响纳米颗粒的主要因素进行了具体的讨论，还对微乳液技术的发展前景作了具体的讨论和分析。     

Ionic Liquids as Size‐ and Shape‐Regulating Solvents for the Synthesis of Cobalt Nanoparticles

Over the last few years, ionic liquids (ILs) have emerged as an important class of reaction media for the synthesis of nanoparticles. The formation and stabilization of nanoparticles was investigated in different ILs to elucidate the effect of the chemical nature of the IL anion, cation and alkyl side chain of the imidazolium. In this context, Co₂(CO)₈ was employed as a precursor and thermally decomposed to the metallic cobalt nanoparticles in a series of selected ILs, where either the IL cation or anion was varied while keeping all of the other parameters constant. The results show that both the molecular volume of the anion and cation and the steric configuration are important aspects to control the formation and stability of nanoparticles in ILs.     

纳米金检测有毒有害物质的研究进展

随着人们对含有重金属的食品,农作物中的农药残留,动物源食品的兽药残留以及包装材料中迁移等有害污染物的关注,开发一个快速、灵敏,经济的对这些有毒有害物质检测方法是非常必要的。纳米金材料凭借其特有的物理和化学性质在此方面显示出巨大的潜力,将纳米金材料用于有毒有害物质的检测领域,成为近几年的一个研究热点。本文介绍了金纳米粒子的基本特征,分析了有害的污染物,其来源和种类,介绍并讨论了金纳米颗粒对有毒有害污染物的检测和应用。     

Shape and size stability of Pt nanoparticles for MeOH electro-oxidation

Pt nanoparticles (NPs) of different shape (cubic and octahedral/tetrahedral) and size (5-10 nm) were synthesized by one-step polyol-based synthetic procedures that permit the concomitant control of the shape and size. The shape and size stability of these particles under repetitive methanol (MeOH) electro-oxidation cycles was investigated by transmission electron microscopy (TEM) as well as cyclic voltammetry (CV). The TEM images of the particles taken before and after being subject to 1000 MeOH electro-oxidation CV cycling and the corresponding hydrogen adsorption/desorption profile in the CVs indicated that, the octahedral/tetrahedral Pt NPs had the highest stability among the samples investigated. Infra-red measurements suggest that this observation may be a result of exceptionally strong interaction of the capping polymer with octa/tetrahedral Pt NPs. These findings indicate that the synthetic procedure employed in this study can be used to synthesize highly stable catalyst particles with tunable shape and size.