Mg-Ta2O5纳米棒涂层的制备、表征及其体外生物活性

采用两步水热处理的方法对钽进行表面改性,在其表面获得具有较小棒间距的掺镁氧化钽纳米棒阵列。通过改变镁元素的掺杂量,观察纳米棒形貌及微观结构的变化。在水热过程中,最佳的乙酸镁溶液浓度为0.05 mol/L,Mg在氧化钽纳米棒膜层中的含量达到4.25at%,以Mg~(2+)形式掺杂入Ta_2O_5纳米棒。使用AFM测量Ta、Ta_2O_5纳米棒和Mg-Ta_2O_5纳米棒样品的粗糙度,发现相比于纯钽片,Ta_2O_5纳米棒涂层和Mg-Ta_2O_5纳米棒涂层的粗糙度有所增加。ICP结果表明,生理盐水中镁离子的析出速率呈现先大幅度增加后变缓的趋势。在体外生物活性测试中,Ta_2O_5纳米棒涂层直到12 d后依然不能诱导出磷灰石;而Mg-Ta_2O_5纳米棒涂层表面不到8 d已经出现沉积磷灰石,Mg-Ta_2O_5纳米棒涂层有效地改善了钽基体表面的生物活性。     

Ag+掺杂ZnWO4纳米棒的微波水热法合成及光催化性能

以硝酸锌(Zn(NO3)2·6H2O)、和钨酸钠(Na2WO4·2H2O)作为起始反应物,利用微波水热法在200℃下合成纳米棒状钨酸锌。利用X-射线粉末衍射、场发射扫描电子显微镜、透射电子显微镜及能谱成分图谱等分析手段对纳米棒状钨酸锌粉体进行表征,并对不同Ag+掺杂量的ZnWO4纳米棒的光催化性能进行了研究。结果表明:Ag+成功的掺入ZnWO4纳米棒中;随着Ag+掺杂量的增加ZnWO4纳米棒的颗粒尺寸也不断增大;Ag+掺杂量2%时纳米棒状钨酸锌粉体的光催化性能最优,但是随着掺杂量的逐渐增加光催化性能反而降低。     

Microwave-assisted synthesis of CePO<Subscript>4</Subscript> nanorod phosphor with violet emission

Monoclinic and hexagonal CePO4 nanoparticles and nanorods were successfully synthesized from Ce(NO3) 3·6H2O and Na3PO4·12H2O solu-tions at pH 1-5 by a 180 W microwave radiation for 60 min.The products were characterized by X-ray diffraction(XRD) ,Fourier transform infrared(FTIR) spectroscopy,and scanning electron microscopy(SEM) .XRD patterns revealed that the products are hexagonal CePO4 structures at pH 2-5,and monoclinic CePO4 structures at pH 1.SEM characterization shows that these products were nanoparticles,short nanorods,and long nanorods,controlled by the pH of the precursor solutions.Optical properties of the nanorods were also investigated by ultraviolet-visible(UV-vis) and photoluminescence(PL) spectroscopy.     

Fabrication and magnetic properties of NiFe2O4 nanorods

NiFe2O4 nanorods have been successfully synthesized via thermal treatment of the rod-like precursor fabricated by Ni-doped α-FeOOH,which was enwrapped by the complex of citric acid and Ni2+.The morphology evolution during the calcination of the precursor nanorods was investigated with transmission electron microscopy(TEM),and the phase and the magnetic properties of samples were analyzed through X-ray diffraction(XRD) and vibrating sample magnetometer(VSM).The results indicated that the diameter of the NiFe2O4 nanorods obtained ranged between 30 and 50 nm,and the length ranged between 2 and 3 μm.As the calcination temperature was up to 600℃,the coercivity,saturation magnetization,and remanent magnetization of the samples were 36.1 kA·m-1,27.2 A·m2·kg-1,and 5.3 A·m2·kg-1,respectively.The NiFe2O4 nanorods prepared have higher shape anisotropy and superior magnetic properties than those with irregular shapes.     

Fabrication of morphology-controlled TiO_2 photocatalyst nanoparticles and improvement of photocatalytic activities by modification of Fe compounds

Our previous studies suggested that redox reaction proceeded separately on specific exposed crystal faces of Ti O2 nanoparticles. Site-selective deposition of metal or metal oxide on Ti O2 specific exposed crystal faces successfully proceeded using the unique reactivity properties on the surface of Ti O2 nanoparticles under photoexcitation. A remarkable improvement of photocatalytic activity of shapecontrolled brookite and rutile Ti O2 nanorods with modification of Fe3compounds was observed under visible light.Crystal face-selective metal compound modification on exposed crystal faces of Ti O2 nanorods with brookite and rutile phases was successfully prepared. Brookite and rutile Ti O2 nanorods prepared by site-selective modification with metal compounds should be ideal visible-light responsive Ti O2 photocatalysts because of the remarkable suppression of back electron transfer from Ti O2 to oxidized metal compounds on the surface of the Ti O2 nanorod with a brookite or rutile phase. In this paper, the development of exposed crystal face-controlled Ti O2 nanorods with rutile and brookite phases was described. The obtained rutile and brookite Ti O2 nanorod, showing remarkably high activity for degradation of organic compounds compared with the photocatalytic activities of anatase fine particles(ST-01), is one of the most active commercially available photocatalysts for environmental cleanup in Japan. The technology of visiblelight responsive treatment for morphology-controlled rutile and brookite Ti O2 nanorods by crystal face-selective modification of Fe3compounds was also discussed in this paper. The Fe3compound-modified rutile and brookite Ti O2 nanorods show much higher activity than conventional visible-light responsive N-doped Ti O2, which is commercially available in Japan.     

Synthesis of GaN nanorods on Si substrates with assistance of the volatilization of ZnO middle layers

GaN nanorods have successfully been synthesized on Si(111) substrates via ammoniating ZnO/Ga2O3 films at 950℃. Ga2O3 thin films and ZnO middle layers were deposited in turn on Si(111) substrates by r.f. magnetron sputtering system. ZnO volatilized at 950℃ in the ammonia ambience and Ga2O3 reacted to NH3 to fabricate GaN nanorods in the later ammoniating process. The volatilization of ZnO layers played an important role in the fabrication. The structure and composition of the GaN nanorods were studied by X-ray diffraction (XRD) and Fourier transform infrared spectrophotometer (FTIR). The orphology ofGaN nanorods was investigated using scanning electron microscopy (SEM) and transmission electronic microscope (TEM). The analyses of measured results revealed that GaN nanorods with hexagonal wurtzite stxucture were prepared by this method.     

Y2O3：Eu^3＋纳米晶的制备及其光学性能研究

以NaOH,Y（NO3）3·6H2O和Eu（NO3）3．6H2O为前驱体,通过添加络合剂PEG-2000,采用水热法,成功地合成了Y2O3：Eu^3＋纳米棒和纳米管,并采用先进的测试手段对其结构和性能进行了表征与测试。探讨了Y2O3：Eu^3＋纳米棒和纳米管的生长机制,同时研究了Y2O3：Eu^3＋纳米晶的光致发光性能。研究结果表明,水热温度、反应时间、NaOH的添加量和PEG-2000对产物形貌有着非常重要的影响,所制备的材料具有Eu^3＋的特征红光发射,并在Eu^3＋的掺杂量为5％（摩尔分数）时样品发光最好。     

疏水性硼酸镧纳米棒的制备及其在菜籽油中的摩擦磨损性能(英文)

采用水热法合成油酸修饰的硼酸镧纳米棒(OA/La BO3·H2O),利用X射线衍射和扫描电镜等测试技术对其微观结构进行表征,并在四球摩擦试验机上考察其在菜籽油中的摩擦磨损性能。结果表明,所制备的OA/La BO3·H2O为直径约50 nm、长达500 nm的疏水性纳米棒。OA/La BO3·H2O能显著提高菜籽油的抗磨减摩性能;当OA/La BO3·H2O的添加量为1%(质量分数)时,菜籽油的抗磨减摩性能最佳。     

晶种法制备单分散的金纳米粒子及光学性能研究

加入聚乙烯吡咯烷酮(PVP)做稳定化试剂,用硼氢化钾还原氯金酸,结合晶种生长法制备了单分散性、粒径小的胶体金。通过晶种生长法,在反应中加入PVP试剂,用抗坏血酸做还原剂,制备了单分散的金纳米棒。结果表明,PVP试剂对金纳米粒子的形貌有重要的影响;加入PVP试剂得到的金纳米粒子(胶体金和金纳米棒)分散性好,无明显的团聚现象。应用透射电镜,纳米粒度分析仪和紫外-可见分光光度计对不同粒径的纳米金进行了表征。     

TiO_2纳米棒复合材料的制备及生长过程研究

采用乙醇/水混合溶剂热法,制备以粉煤灰空心微球为基底的TiO_2纳米棒复合材料,研究了不同制备条件下纳米棒的形貌特点,分析其生长过程。结果表明:TiO_2纳米棒为金红石相,其形貌和尺寸与乙醇溶剂、钛源浓度、反应时间密切相关,适量的乙醇溶剂,使纳米棒结晶效果变好,四方棒状形貌明显,随着钛源浓度和反应时间的增加,TiO_2纳米棒尺寸增大;TiO_2纳米棒复合材料对罗丹明B具有较好的光催化降解效果。     

SDS／Vc／H2O微乳液中纳米金的合成

在SDS／Vc／H2O微乳液中用0．001mol·L^-1HAuCl4溶液代替组分水，以Vc作还原剂制备纳米金。紫外一可见光谱和扫描电镜实验结果表明，所制备的金纳米粒子的粒径在5-20nm之间；在固定SDS／Vc的质量比为50／50条件下，粒子的粒径随微乳液中HAuCl4（aq）含量的增加而增加。初步探讨了在SDS／Vc／H2O微乳液中合成纳米金的机制。     

Synthesis of ZnO nanorods and their optical absorption in visible-light region

Single crystalline ZnO nanorods were prepared by the hydrothermal method with synthesized ZnCl2·4Zn(OH)2 as the precursor. Morphologies of the nanorods were controlled by various reaction conditions with cetyltrimethylammo-nium bromide (CTAB) as the modifying agent. The nanorods were characterized by XRD, TEM, UV-Vis spectra, and IR spectra. The microstructure of holes in nanosize was observed on the surface of the nanorods. The UV-Vis spectra indicate that the as-prepared ZnO nanorods have absorption of visible-light as well as ultraviolet-light. Therefore, these nanorods may be good candidates for visible-light photocatalysis materials from the viewpoint of practical applications. The reason for visible-light absorption was discussed in this article.     

金属热还原法制备钛铝中间合金

以TiO_2为原料,KClO_3为发热剂,Al为还原剂和合金化剂,Ca为深度还原剂,通过金属热还原法制备钛铝中间合金,考察了单位质量热效应、造渣剂配比和还原剂加入量及组成对反应过程稳定性、合金成分及收率的关系。研究表明:用Ca和Al作为还原剂时,体系绝热温度分别是2426和1806 K,反应制得的钛铝中间合金由Ti Al、Ti_3Al和少量的Al_2O_3夹杂相组成,化学分析合金中Ti、Al、O质量分数分别为58.36%、40.19%和1.41%。     

纳米棒状Li-Ti-O化合物的制备与电化学嵌锂性能

采用在碱性条件下的水热法,合成了钛酸钠纳米棒,在此基础上用熔融盐离子交换方法制备了钛酸锂中间体,在400~700 ℃的空气气氛下烧结,得到的纳米棒状Li-Ti-O化合物由贫锂的锐钛矿结构LixTiO2和立方尖晶石结构Li4Ti5O12 两相构成。用恒电流充放电研究了其电化学嵌/脱锂性能。结果表明,经600 ℃热处理的纳米棒状Li-Ti-O化合物具有最佳的比容量、循环稳定性和高倍率放电性能。     

Preparation of GaN Nanorods by Rare Earth Metal Tb Catalyst-Assisted Process

利用稀土金属Tb作为催化剂,通过氨化磁控溅射在Si(111)衬底上的Ga203/Tb薄膜制备出GaN纳米棒.X射线衍射和傅里叶红外吸收谱测试结果表明,制备的样品为六方结构的GaN.利用扫描电子显微镜、透射电子显微镜和高分辨透射电子显微镜对样品进行测试,结果显示样品为单晶结构的纳米棒,直径为80～200 nm,长度达几十微米.最后简单地讨论了GaN纳米棒的生长机制.     

Preparation of NaV1−xAlxPO4F cathode materials for application of sodium-ion battery

The effects of Al doping on the electrochemical properties of NaVPO4F as a cathode material for sodium-ion batteries were investigated. Al-doped NaV1-xAlxPO4F （x=0, 0.02） samples were prepared by a simple high temperature solid-state reaction involving VPO4 and NaF for the application of cathode material of sodium-ion batteries. The crystal structure and morphology of the material were studied by Flourier-infrared spectrometry（FT-IR）, X-ray diffractometry（XRD） and scanning electron microscopy（SEM）. The results show that NaV1-xAlxPO4F （x=0, 0.02） has a typical monoclinic structure. The effects of Al doping on the performance of the cathode material were analyzed in terms of the crystal structure, charge-discharge curves and cycle performance. It is found that NaV0.98Al0.02PO4F shows an improved cathodic behavior and discharge capacity retention compared with the undoped samples in the voltage range of 3.0-4.5 V. The electrodes prepared from NaV0.98Al0.02PO4F deliver an initial discharge capacity of 80.4 mA.h/g and an initial coulombic efficiency of 89.2%, and the capacity retention is 85% after 30th cycle. Though the Al-doped samples have lower initial capacities, they show better cycle performance than Al-free samples.     

Optimization of dielectric constant temperature coefficient of pyrochlores containing bismuth

1　INTRODUCTIONDielectric ceramics are widely used with ad vances in microelectronic technologies. Bismuth based pyrochlores exhibit well known high fre quency dielectric properties for multilayer capaci tor. Group of pyrochlore structured compounds isof general formula A2B2O7(where A is trivalent orbivalent cations and B is quadrivalent and quinque valent cations). As a member of the pyrochlorefamily of compound, bismuth zinc niobate is a typi cal high frequenc…     

纤维锌矿ZnO纳米棒的合成及高选择性酒精传感器的研制

以无机盐做前驱体，采用有机溶液氧化-还原法合成了ZnO纳米棒，对终产物通过XRD、Raman spectrum、SEM和TEM进行结构检测表明，产物为纤维锌矿型结构，呈棒状，直径大约为50～80nm，长度大约为500nm；对材料的气敏性能测试表明，基于该材料制成的气体传感器对酒精有很好的响应和很好的选择性，且响应-恢复迅速。     

Al-Mg-Sc中间合金的制备

在非真空条件下用氟化物熔盐体系镁 (铝 )热还原法制备了Al Mg Sc中间合金 ,讨论了金属还原剂的选择及还原温度、时间等工艺条件对钪收率的影响 ,并研究制定了氧化钪固相氟化制备氟化钪熔盐工艺。采用Al Mg合金熔体为还原剂经二次还原后钪收率 >80 %,制备的Al Mg Sc中间合金铸锭中钪含量 >1.9%,最佳的还原反应温度为 110 0K ,还原时间 40min .。氟化钪还原产生的初生态钪与铝作用形成稳定的Al3 Sc化合物 ,促进了还原的进行 ,使钪收率得到了大幅度提高。     

Cu包覆纳米Al_2O_3复合粉体的化学镀法制备

纳米Al2O3的力学性能优异,是一种理想的Cu基纳米复合材料的增强体,然而其与Cu基体的润湿性较差。为了改善其与Cu基体的润湿性,增强界面的结合力,通过化学镀工艺在其表面镀Cu,并采用SEM、TEM、XRD和EDS系统研究了镀液中络合剂及还原剂类型、镀液温度及施镀条件等重要因素对化学镀过程、镀膜质量的影响,进而优化了施镀工艺,获得了粒径均一、分散良好的Cu包覆纳米Al2O3复合粉体,为A12O3/Cu纳米复合材料的制备打下了良好的基础。