Journal of the American Chemical Society
We present a metal-catalyst-free CVD process for the high-efficiency growth of single-walled carbon nanotubes (SWNTs) on surface. By applying a 30-nm-thick SiO(2) sputtering deposited Si or Si/SiO(2) wafer as substrate and CH(4) as a carbon source, dense and uniform SWNT networks with high quality can be obtained without the presence of any metal species. Moreover, a simple patterned growth approach, using a scratched Si/SiO(2) wafer as substrate, is also presented for the growth of SWNTs with good position controllability. Our finding of the growth of SWNTs via a metat-catatyst-free process will provide valuable information for understanding the growth mechanism of SWNTs in-depth, which accordingly will facilitate the controllable synthesis and applications of carbon nanotubes.
关键词:
nanoparticles
Chih-Chia HUANG
,
Chen-Sheng YEH
材料科学技术（英文）
Porous cube-like crystalline In2O3 nanoparticles with an average diagonal length of 34.8 nm were fabricated by a laser ablation-reflux process to form In(OH)3, followed by a calcination treatment to yield porous In2O3. HRTEM (high-resolution transmission electronic microscopy), XRD (X-ray diffraction), BET (Brunauer-Emmett-Teller), and XPS (X-ray photoelectron spectroscopy) analysis were used to characterize their crystalline structures, grain sizes, surface areas, and surface compositions. The as-prepared porous indium oxides were tested for their sensing properties toward ethanol. Non-porous In2O3 nanopowder (about 40 nm) was also examined in order to compare the results with the as-prepared porous In2O3 nanomaterials. The porous In2O3 exhibited much better performance than that of non-porosus In2O3, and showed enhanced sensitivity with a lower detection limit than other reported In2O3-based materials when exposed to ethanol. Good gas sensitivity and linear behavior as a function of ethanol concentration were observed in the porous In2O3 nanoparticles.
关键词:
In2O3
,
porosity
,
nanoparticles
,
gas
,
senso
C.Bouvy
,
B.L.Su
材料科学技术（英文）
Optoelectronic nanocomposites are a new class of materials, which exhibit very interesting and particular properties and attract a growing attention due to their potential applications in information storage and optoelectronic devices. Zinc oxide, ZnO, is one of the most interesting binary semiconductor (3.37 eV) with very important optical properties, which can be used in the fields such as short wavelength lasers, blue light emitting diodes, UV detectors, gas sensors, etc. This paper reviews the very recent progress in the preparation of silica-based ZnO nanocomposites. After an introduction reviewing the theoretical background, the article will begin with a survey of the optical properties and the quantum size effect (QSE) of ZnO/SiO2 nanocomposites prepared by the inclusion of ZnO nanoclusters inside silica mesoporous materials. The second part will focus on one of the most interesting properties of ZnO/SiO2 nanocomposites, which is the random lasing effect after one- and two-photon excitation. The final part will deal with the introduction of ZnO nanoparticles inside microporous zeolites and the observation of QSE. For comparison, the photoluminescence (PL) and QSE properties of ZnS nanoparticles occluded in mesoporous media are also described. New potential applications will be discussed since short-wavelength devices are required by industry to design, for instance, new information storage supports and biolabelling devices.
关键词:
ZnO nanoparticles
,
nanoparticles
,
microporous
,
and
,
mesopo
黄选民
,
幸泽宽
,
董世运
,
颜明华
,
张桂
材料保护
针对某型发动机压气机整流叶片榫头磨损,应用纳米颗粒复合电刷镀技术进行修复.通过控制电刷镀工艺参数,获得了性能稳定的纳米颗粒复合镀层,并检测了镀层的结合强度、显微硬度、基体渗氢量、耐磨性能及接触疲劳寿命.结果表明:n-Al2O3/Ni镀层、n-SiO2/Ni镀层以及快镍镀层的结合强度均能满足使用要求;与快镍镀层相比,n-Al2O3/Ni镀层硬度提高了25%,对基体的渗氢量降低了47%,耐磨性能是快镍镀层的2.5倍,接触疲劳寿命增加,而n-SiO2/Ni镀层硬度提高了12%,对基体的渗氢量降低了41%,耐磨性能是快镍镀层的2.2倍,接触疲劳寿命增加;纳米颗粒复合电刷镀比普通电刷镀快镍的加工效率提高近1倍;采用纳米颗粒复合电刷镀修复的叶片通过了长试考核,能满足使用性能要求.
关键词:
纳米颗粒
,
复合电刷镀
,
快镍
,
整流叶片
裘迪
,
朱宏
材料导报
以生物可降解材料聚乳酸-羟基乙酸(PLGA)为载体制备了载紫杉醇纳米粒,重点考察了纳米粒的体外释放特性.采用乳化-溶剂挥发法制备了载紫杉醇PLGA纳米粒,其平均粒径为200nm,载药量为21%,包封率为89.44%;体外释药符合Higuchi方程:Q=3.8796t1/2+30.4649(r=0.9397),同时载紫杉醇纳米粒具有一定的缓释作用.
关键词:
聚乳酸-羟基乙酸
,
纳米粒
,
紫杉醇
,
体外释放
黄溢淳
,
张兆春
,
姜惠轶
无机材料学报
doi:10.3724/SP.J.1077.2011.00579
利用水合肼液相还原法在纳米磷化镓(GaP)粉体表面沉积贵金属铂(Pt), 制备低Pt担载量Pt(0.80 wt%)/GaP和高Pt担载量Pt(4.2 wt%)/GaP纳米粉体样品. 在可见光照射条件下, 分别以GaP和Pt/GaP纳米粉体作为光催化剂, 对结晶紫水溶液进行光催化降解. 实验结果表明, GaP和Pt/GaP两种纳米粉体皆具有可见光响应光催化性能; Pt担载量对Pt/GaP纳米粉体的光催化性能有着较大的影响, 低Pt担载量Pt(0.80 wt%)/GaP纳米粉体的结晶紫光催化脱色率高于GaP纳米粉体, 而高Pt担载量Pt(4.2 wt%)/GaP粉体的结晶紫光催化脱色率则低于GaP纳米粉体.
关键词:
纳米粉体
,
gallium phosphide
,
platinum
,
photocatalysis
,
crystal violet
