模拟体液法制备纳米级羟基磷灰石

用模拟体液法制备纳米羟基磷灰石(hydroxyapatite,HAP or HA)粉体。研究了反应温度、反应浓度和反应时间对合成的影响。结果发现,制备纳米级羟基磷灰石的最佳工艺条件为:反应温度60℃,浓度为15倍的模拟体液(simulate body fluid,SBF),反应时间为10h。在此工艺条件下制备的羟基磷灰石粉体的微观形貌为球形颗粒,平均颗粒直径为30 nm。     

简单方法制备羟基磷灰石中空微球

无需添加任何有机物和金属离子, 以易得的中空球形碳酸钙(CaCO3)与磷酸氢二钠(Na2HPO4)作为反应物在常压下制备出羟基磷灰石中空微球. 通过场发射扫描电子显微镜(FESEM)、扫描电子显微镜(SEM), X射线粉末衍射(XRD)等手段对制备的羟基磷灰石中空微球的结构、组成和形貌进行了表征, 考察了不同反应温度对中空球形貌的影响. 实验结果表明, 所制备的羟基磷灰石微球是由短针状的纳米粒子组成的, 直径为2-4 μm. 对反应机理进行了初步探讨.     

羟基磷灰石包覆γ-Fe2O3担载氧化钼:一种新型磁性可回收的烯烃环氧化多相催化剂

制备了羟基磷灰石(HAP)包覆纳米γ-Fe2O3颗粒复合材料(HAP-γ-Fe2O3),并进一步采用浸渍法担载氧化钼(MoOx/HAP-γ-Fe2O3).高分辨透射电镜结果表明,γ-Fe2O3纳米颗粒被包覆于HAP当中,平均粒径为1～3 nm.所制各催化剂对以叔丁基过氧化氢为氧化剂的烯烃环氧化反应显示了良好的催化活性,...     

镁掺杂纳米羟基磷灰石的制备及其在载药方面的应用

通过逐步沉淀反应一锅法制备了一系列不同含量的镁掺杂纳米羟基磷灰石。通过硝酸镁、硝酸钙不同的投料物质的量比调控纳米颗粒的形态和尺寸。通过透射电子显微镜(TEM)、X射线衍射(XRD)等分析手段对镁掺杂纳米羟基磷灰石进行物理化学性能表征,用MTT法评价其体外细胞毒性。研究结果表明:镁掺杂纳米羟基磷灰石呈现束状纳米纤维形态、比表面积大、细胞毒性较低;将其作为载体负载抗癌药物顺铂,具有很好的载药能力,载药量可达54%,该载药纳米颗粒还具备缓释特性(72 h释药量达到41.72%)和很好抑制癌细胞生长的效果。     

新型半导体可见光催化剂纳米锰酸钇

采用聚丙烯酰胺凝胶法制备了锰酸钇(YMnO3)纳米颗粒,并运用X射线衍射、扫描电镜和紫外可见漫反射光谱对样品进行了表征.结果表明,制得的YMnO3纳米晶主要为六方钙钛矿结构,兼有少许的正交钙钛矿结构,且颗粒粒度均匀、形貌规整、呈类球形,平均颗粒尺寸约为45 nm.另外,测得YMnO3纳米颗粒的光学带隙值为1.31 eV...     

新型FITC掺杂的二氧化硅荧光纳米粒子的合成及其应用于pH传感的研究

将异硫氰酸荧光素(FITC)与3-氨基丙基三甲氧基硅烷(APTMS)反应制得前驱体FITC-APTMS,采用油包水微乳液法,利用APTMS与正硅酸乙酯(TEOS)的共水解与聚合作用,制备了FITC掺杂的二氧化硅核壳型荧光纳米粒子。经TEM与荧光光谱表征及光稳定性实验与染料泄露实验等,表明所制得纳米颗粒呈规则球形,粒径为(150±15)nm,具有良好的单分散性与光稳定性,不易发生染料泄露。这种纳米颗粒对pH值敏感,在pH3.6～9.7范围内,荧光强度与溶液酸度有良好的响应,其中在pH6.0～9.0之间呈良好的线性关系,此纳米颗粒能被单个小鼠神经干细胞吞噬,可应用于细胞的pH值实时监测。     

离子热合成形貌可控的羟基磷灰石超细粉体

室温离子液体作为溶剂,以离子热合成法合成了羟基磷灰石超细粉体。当改变不同的离子液体作为溶剂时,可以相应调整羟基磷灰石的形貌。对羟基磷灰石分别采用X-射线粉末衍射(XRD),扫描电子显微镜(SEM),傅立叶变换红外光谱仪(FTIR)等进行表征。实验结果表明:所得到的羟基磷灰石为部分CO32-取代的羟基磷灰石,在选用EmimBF4为溶剂时所合成样品颗粒的尺寸、形貌更加规则、均一。与水作为溶剂相比,以离子液体BmimBr作为溶剂所合成的羟基磷灰石材料对有机染料碱性品红的饱和吸附量为43.78 mg·g-1,具有较好的吸附性能。     

以纳米微晶纤维素为模板的酸催化水解法制备球形介孔TiO_2

以纳米微晶纤维素(NCC)为模板剂,采用酸催化水解法制备了球形介孔TiO2(SP-TiO2).并采用扫描电镜、透射电镜、X射线衍射、紫外-可见漫反射光谱和低温N2吸附-脱附等手段对其进行了表征.结果表明,所制SP-TiO2为直径100～200nm的规整球形颗粒,单个球形颗粒由粒径为10～20nm的TiO2小晶粒组成.其介孔孔径为8.2～13.5nm,且随焙烧温度的升高而增大.NCC长链结构之间羟基键合所形成的狭小空间构成的微反应器,可有效限制TiO2前驱体的生长和团聚,诱导其晶粒自组装成球形结构,并抑制由锐钛矿相向金红石相转变.600oC焙烧的SP-TiO2表现出最高的光催化活性,对苯酚降解率达89%.     

爆轰法制备球形纳米CeO2粉末

采用爆轰合成的方法,以Ce(NO3)3·6H2O为原料,制得了CeO2纳米粒子. 炸药采用黑索金粉,添加剂为CO(NH2)2,NaNO2. 爆轰产物经水洗,烘干后,利用X射线衍射仪器和高分辨率透射电镜对实验结果进行了分析. XRD结果表明,该法所得到的CeO2为立方晶系,颗粒平均粒度为33 nm. TEM图像显示其颗粒呈球形,颗粒大小主要分布在20～40 nm之间,颗粒具有较好的分散性. 球形纳米CeO2颗粒的形成原因有两点:(1) 由于爆轰过程的快速性和急剧冷却的特点,CeO2晶粒来不及择优生长; (2) 产物Na2CO3的熔点较低,爆轰时呈熔融状态包覆在CeO2晶核的周围,阻隔了CeO2晶粒的团聚生长.     

表面修饰CdS和(CdS)ZnS纳米晶的性能研究

在水相中合成了CdS纳米微粒,以ZnS对其进行表面修饰,得到具有核壳结构的(CdS)ZnS水溶性纳米晶。采用红外光谱、X射线衍射(XRD)、透射电镜(TEM)表征其粒度和形貌,紫外-可见吸收光谱(UV)、荧光光谱表征其光学特性。制得的CdS近似呈球形,直径为8nm;CdS纳米颗粒表面经ZnS修饰后,其荧光发射峰强度显著增强,表面态发射减弱。     

Preparation and characterization of composite nanofibers of polycaprolactone and nanohydroxyapatite for osteogenic differentiation of mesenchymal stem cells

Nanocomposites of nanohydroxyapatite (nHAP) dispersed in poly(?-caprolactone) (PCL) were prepared by electrospinning (ES) to obtain PCL/nHAP nanofibers. Nanofibers with similar diameters (340 ± 30 nm) but different nHAP concentrations (0-50%) were fabricated and studied for growth and osteogenic differentiation of bone marrow mesenchymal stem cells (MSCs). The nanofibrous membranes were subjected to detailed analysis for its physicochemical properties by scanning electron microscopy (SEM), thermogravimetric analysis, X-ray diffraction, Fourier-transform infrared spectroscopy, and mechanical tensile testing. nHAP particles (~30 nm diameter) embedded in nanofibers increased the nanofibrous membrane's ultimate stress and the elastic modulus, while decreased the strain at failure. When cultured under an osteogenic stimulation condition on nanofibers, MSCs showed normal phenotypic cell morphology, and time-dependent mineralization and osteogenic differentiation from SEM observations and alkaline phosphatase activity assays. The nanofibers could support the growth of mesenchymal stem cells without compromising their osteogenic differentiation capability up to 21 days and the enhancement of cell differentiation by nHAP is positively correlated with its concentration in the nanofibers. Energy dispersive X-ray analysis of Ca and P elements indicated mineral deposits on the cell surface. The mineralization extent was significantly raised in nanofibers with 50% nHAP where a Ca/P ratio similar to that of bone was found. The present study indicated that electrospun composite PCL/nHAP nanofibrous membranes are suitable for mineralization of MSCs intended for bone tissue engineering.     

Transport behavior of humic acid-modified nano-hydroxyapatite in saturated packed column: effects of Cu, ionic strength, and ionic composition

The surfaces of nano-hydroxyapatite (nHAP) used for contaminated soil and groundwater remediation may be modified to render nHAP highly mobile in the subsurface. Humic acid (HA) is widely used to modify and stabilize colloid suspensions. In this work, column experiments were conducted to determine the effects of contaminant (e.g., Cu) concentration, ionic strength (IS), and ion composition (IC) on the transport behavior of HA-modified nHAP in saturated packed columns. IS and nature of the cation had strong effects on the deposition of nHAP, and the effect was greater for divalent than for monovalent cations. Divalent cations have a greater capacity to screen the surface charge of nHAP, and Ca(2+) bridges the HA-modified nHAP colloidal particles, which causes greater deposition. Moreover, Cu(2+) had a greater effect on the transport behavior than Ca(2+) due to their strong exchange with Ca(2+) of nHAP and its surface complexation with nHAP. The relative travel distance L(T), of the injected HA-modified nHAP colloids, ranges from less than one to several meters at varying Cu concentrations, ISs, and ICs in saturated packed columns. The results are crucial to evaluate the efficacy of nHAP on the remediation of contaminated soil and groundwater environments.     

Molecular Mechanism Study on Effect of Biodegradable Amino Acid Ester–Substituted Polyphosphazenes in Stimulating Osteogenic Differentiation

Amino acid ester substituted polyphosphazenes are osteoactive benefiting from their phosphorus‐containing chemical structure, which highlights interests in bone tissue engineering. To correlate their chemical structures with cell activities, in this study, poly[(ethyl alanato)_0.3(ethyl glycinato)_0.7phosphazene] (PAGP) and poly[(ethyl phenylalanato)_0.3(ethyl glycinato)_0.7phosphazene] (PPGP) are synthesized to carry out studies on cell osteogenic differentiation. In the non‐contact culture manner, bone mesenchymal stromal cells (BMSCs) are cultured in transwell chambers containing PAGP or PPGP films, while the cells and the materials do not contact. In the contact culture manner, BMSCs are cultured on the PAGP or PPGP films. In the meantime, solutions containing PAGP or PPGP degradation products (i.e., phosphate, ammonium, and corresponding amino acids) are applied for cell culture using inorganic phosphate (Pi) ion as control. Thus, the influences from substrate surface and degradation products can be identified separately. The results reveal that both the phosphorus‐containing surface of PAGP and PPGP films and their degradation products play significant roles in regulating cell behaviors. In comparison with PAGP, PPGP seems able to provide relatively stable phosphorus‐containing surface to strengthen the cell‐scaffold interaction because of its slower degradation rate and higher Young's modulus, leading to greater promotion in osteogenic differentiation via contact effect.     

宽带隙Cu(In,Al)Se2薄膜的制备及表征

以特殊脉冲电沉积方法制备CuInSe2(CIS)前驱体薄膜, 通过真空蒸镀法在CIS薄膜上沉积Al膜, 经硒化退火后在氧化铟锡(ITO)基底上制备了Cu(InAl)Se2(CIAS)薄膜. 采用扫描电子显微镜(SEM)、X射线能谱(EDS)、X射线衍射(XRD)、X射线光电子能谱(XPS)、紫外-可见吸收光谱(UV-Vis)对其形貌、结构、成分及光学吸收性质进行了表征. 结果表明, 制备的CIAS薄膜颗粒均匀, 表面平整致密, 呈黄铜矿结构. 薄膜在可见光区具有良好的吸收, 带隙约为1.65 eV.     

Electrochemical Behavior of Dental Ni‐Cr Wirolloy Coated with Eco‐friendly Films in Artificial Saliva

The electrochemical corrosion behavior of the non‐precious Ni‐Cr Wirolloy, being used in dentistry, was investigated before and after applying of two types of eco‐friendly coatings, polyvinyl silsesquioxane (PVS) and nano‐hydroxyapatite (nHAP) separately in artificial saliva solution at 37 °C for 14 d of immersion. The study aimed to investigate the effectiveness of the introduced coating films in enhancing the corrosion resistance of the alloy, and in decreasing the leaching of the toxic Ni ions from the alloy into the environment. The electrochemical corrosion investigation methods used are; open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The evaluated results revealed that the electrochemically coated alloy with PVS. prepared at cathodic potential showed higher corrosion resistance and more stable film compared to that prepared by conventional dip‐coating method. At the same time, the nHAP electrochemically coated film provided the best anti‐corrosion properties over all examined time intervals. The obtained results were confirmed via surface analysis, which assured the formation of the prepared coatings on the alloy surface. Chemical analysis of the corrosion product/solutions showed that the effect of electrochemically deposited nHAP and PVS. polymer films in suppression of Ni ions leaching is similar and slightly higher than that of the chemically coated PVS. one; however, all of them are efficient in decreasing the leaching of the risky Ni ions into the solution.     

TiO2薄膜的Ag改性及光催化活性

 用光化学沉积法对纳米TiO2薄膜进行了Ag改性,用漫反射紫外-可见光谱、扫描电子显微镜和X射线光电子能谱分析了Ag-TiO2薄膜的光谱特征、表面形貌和表面组成. 以苯酚为模拟污染物,在不同波长光源及有氧和无氧条件下考察了Ag-TiO2薄膜的光催化活性. 结果表明,当银沉积量大于 0.0150 mg/cm2时, Ag-TiO2薄膜对紫外光的吸收发生了明显的蓝移,同时在346 nm附近出现了小的吸收峰且该峰随着银沉积量的增加逐渐向长波方向移动. 沉积在TiO2薄膜表面的银颗粒大小不均匀,主要以单质银的形式存在,也生成了部分Ag2O; 相对于TiO2薄膜, Ag-TiO2薄膜表面吸附氧的含量明显增大. Ag-TiO2薄膜的光吸收特性对其催化活性影响较大. 在低压汞灯及有氧参与的条件下,银沉积量为0.0523 mg/cm2的Ag-TiO2薄膜的催化活性最高, 其反应速率常数是TiO2薄膜的1.16倍. Ag+更易沉积在较大n值的Ag簇上,其颗粒大小不可能完全均匀. Ag-TiO2薄膜的光吸收特性、 Ag簇的大小以及Ag对O2的吸附作用是决定Ag-TiO2薄膜催化活性的主要因素.     

Preparation and Characterization of Nano-Structured SiO2 Thin Films on Carbon Steel

Nano-structured SiO2 thin films were prepared on the surface of carbon steel for the first time by LPD. The compositions of the films were analyzed by XPS, and the surface morphology of the thin films were observed by AFM. The thin films were constituted by compact particles of SiO2, and there was no Fe in the films. In the process of film forming, the SiO2 colloid particles were deposited or absorbed directly onto the surface of carbon steel substrates that were activated by acid solution containing inhibitor, and corrosion of the substrates was avoided. The nano-structured SiO2 thin films that were prepared had excellent protective efficiency to the carbon.     

真空蒸镀法制备锡薄膜及其嵌锂电化学性能

采用真空蒸镀法在铜片基底上沉积锡薄膜作为锂离子电池负极材料,对所制备的锡薄膜采用扫描电子显微镜、X射线衍射表征,研究了其表面形貌和组成。 将制备的薄膜在手套箱中组装成CR2032型钮扣式电池,进行电化学测试,研究其电化学性能。 实验结果表明,在相同蒸发时间和基底温度的条件下,随着蒸发功率的增加,沉积的锡颗粒逐渐增大,相应的电化学性能降低。 以蒸发功率200 W、基底温度150 ℃制得的样品粒径为100~200 nm,含有Cu6Sn5合金相,以0.2C倍率充放电循环20周后放电容量达527 mA·h/g。     

Heterogeneous reactivity of chlorine atoms with sodium chloride and synthetic sea salt particles

The uptake of chlorine atoms on sodium chloride (NaCl) and synthetic sea salt (SSS) particles was studied using a discharge flow reactor coupled to a molecular beam mass spectrometer. The reactive surfaces were prepared by coating the inner surface of the reactor using two different methods: either by depositing size-selected particles on halocarbon wax or by spray depositing thin films using a constant output atomizer. The observed uptake coefficients of Cl˙ on NaCl particles are γ(NaCl)(Cl) ≈ 2 × 10(-2) for size-selected particles or γ(NaCl)(Cl) ≈ 5 × 10(-2) for thin films and for SSS particles γ(SSS)(Cl) ≈ 4 × 10(-3). Heterogeneous recombination of Cl atoms to Cl(2) molecules was observed for the two solid surfaces. The study was performed over the temperature range 258 to 353 K. The temperature dependence of the uptake was observed and the heat of adsorption of Cl˙ on NaCl particles was estimated at Q(ads) = 63 kJ mol(-1) assuming an Eley-Rideal mechanism. The role of surface adsorbed water has also been shown. The atmospheric implications of these findings are discussed briefly.     

Fabrication of hollow spheres and thin films of nickel hydroxide and nickel oxide with hierarchical structures

Hollow spheres and thin films of Ni(OH)(2) and NiO with unusual form and hierarchical structures have been synthesized by a simple solution chemistry method. First, in situ formed Ni(OH)(2) nanoflakelets organized on the surface of styrene-acrylic acid copolymer (PSA) latex particles to form core/shell structures. Ni(OH)(2) hollow shells built up with nanoflakelets were obtained after subsequent removal of the core latex particles by dissolving PSA latex in toluene; the removal of the cores by calcinations would result in NiO hollow shells, also with hierarchical structures. BET calculation showed the surface area of the NiO hollow spheres was 156 m(2)/g. The nanoflakelets could also organize themselves into thin films with hierarchical structures. It is anticipated that these novel structures will have some unique applications in Ni-based batteries and other potentials.