水下电弧放电法制备洋葱状富勒烯

探索了纯石墨电极在水中放电制备洋葱状富勒烯（Onion-like fullerenes，OLFs）的过程和工艺。用高分辨透射电镜（High resolution transmission electron microscope。HRTEM）对生成的OLFs进行了形貌、结构的观察与表征。分析结果表明制得的OLFs具有各种不同形状的内核。石墨化程度很高，直径分布在5nm～40nm范围内。在一定范围内随着电流强度的增大OLFs的产量和产率都有不同程度的提高。     

功能化洋葱状富勒烯在裸鼠体内的流动

采用L-半胱氨酸盐酸盐,通过化合接枝法对洋葱状富勒烯进行功能化,合成水溶性L-半胱氨酸富勒烯衍生物。利用扫描电子显微镜(SEM)、X射线衍射(XRD)、红外光谱(IR)、热重分析(TGA)及X射线能谱分析(XPS)对所制样品进行表征。结果表明:L-半胱氨酸富勒烯衍生物表面具有-OH、-NH3等亲水性基团,水溶性良好。裸鼠实验表明,合成的L-半胱氨酸富勒烯衍生物在生物体组织细胞中具有很好的分布,可以顺利溶入生物体体液并具备良好的流动性。     

洋葱状富勒烯的CCVD法制备及其形貌特征

采用催化化学气相沉积法（CCVD）制备了洋葱状富勒烯（OFs)，借助高分辨透射电镜（HRTEM）观察和分析了其形貌结构。结果发现，以负载Co^2 的Y型沸石为催化剂，C2H2为碳源，反应温度为700℃时，单位催化剂产炭率的质量分数为66%，其中洋葱状富勒烯的收率可达产炭率体积分数的20%以上，并认为OFs的生长机理为的由内到外逐层石墨化的气固（VS）模式。     

液苯介质放电制备洋葱状富勒烯

以液体苯(C6H6)为放电介质,石墨做电极,成功地制备了洋葱状富勒烯(Onion-like Fullerenes,OLFs)。重点考察了电流对OLFs产量的影响,利用高分辨透射电镜(HRTEM)和X-射线衍射(XRD)对所得产物进行了表征。结果表明:电流大小是影响OLFs产量的主要因素,所制OLFs直径分布可控制在10nm~30nm范围内。     

洋葱状富勒烯的制备及摩擦性能研究

通过水下电弧放电法制备出洋葱状富勒烯(OLFs).采用高分辨透射电镜(HRTEM)、X射线衍射(XRD)分析了OLFs的晶体结构和形貌,并通过热重(TGA)考察了OLFs的热稳定性.在MRS-10A型四球摩擦试验机上测试了OLFs作为长城牌SE级15W-40汽油机油添加剂的摩擦性能.结果表明,所制备的OLFs具有较高的石墨化程度,直径约25nm,外形呈球状并具有一定的空心结构;在空气中的热稳定性维持到600℃以上.在不同的质量分数和载荷下,OLFs作为润滑油添加剂在减摩性能上均优于碳纳米管(CNTs).     

纳米坡缕石/铜复合材料对钢球摩擦副的摩擦学性能

采用化学还原法和球磨共混添加法制备了纳米坡缕石/铜（P/Cu）复合材料,采用粒度分析仪和透射电子显微镜（TEM）对复合纳米粒子的粒度和形貌进行表征。利用四球摩擦磨损试验机考察了不同纳米P/Cu添加量和不同P与Cu配比的复合粉体作为润滑油添加剂对高副钢球摩擦副的摩擦学性能,利用扫描电子显微镜（SEM）、X射线能谱仪（EDS）对摩擦表面进行形貌、元素性能分析。结果表明,所制备的纳米P/Cu粒径基本小于100 nm,分散稳定性良好,在纳米P/Cu为1wt%且P：Cu＝3：1（质量比）添加量下表现出最优的摩擦学性能,其钢球磨斑直径比基础油的减小了20.7%。纳米P/Cu可在摩擦表面生成含Mg、Al、Si和Cu等元素的自修复膜,补偿摩擦磨损且使摩擦表面变光滑。     

纳米金属/层状硅酸盐复合润滑添加剂的摩擦学性能

采用机械化学法制备了纳米铜/蛇纹石复合润滑材料,利用微动摩擦磨损试验机考察了其作为润滑油添加剂的摩擦学性能,借助纳米压痕仪（nano-in-denter）、扫描电子显微镜（SEM）、能量色散谱仪（EDS）及光电子能谱仪（XPS）对磨损表面进行了表征,探讨了减摩抗磨机理。结果表明复合润滑材料具有优异的摩擦学性能,其摩擦因数及磨损率分别较基础油降低约16.4%和69.2%。复合润滑剂颗粒参与了摩擦界面复杂的理化作用,形成了致密光滑的保护膜,主要由Fe、Si等元素组成,具有较高的微观力学性能,提高了摩擦表面的磨损抗力,显著地降低了摩擦磨损。     

Characterization of Cu3SbS4 microflowers produced by a cyclic microwave radiation

Copper antimony sulfide (Cu₃SbS₄) crystals were produced from mixtures of different molar ratios of CuCl, SbCl₃ and thiourea in 40 and 60 ml ethylene glycol (EG) by a 300 W cyclic microwave radiation (CMR) for different lengths of time. In the present research, tetragonal Cu₃SbS₄ microflowers, characterized by X-ray and electron diffraction including electron microscopy and Raman analyses, were successfully produced in the 40 ml solution containing 2:2:4 molar ratio Cu:Sb:S for 40 cycles. Their UV-visible absorption was studied to determine the energy gap (E_g). A formation mechanism was also proposed to relate with the experimental results.     

Preparation and transformation to hollow nanospheres of wrapped CuS nanowires by a simple hydrothermal route

In this paper we reported the preparation of wrapped CuS nanowires via a simple hydrothermal reaction at 180 °C for 2 h, employing CuSO₄·5H₂O and thiourea as reactants in the absence of any structure-directing agent. SAED pattern showed that the wrapped CuS nanowires were polycrystalline, which was comprised of small nanoparticles. TEM observations showed that wrapped nanowires could grow and further transfer to hollow spheres with the prolonging of the reaction time from 2 h to 13. The UV-Vis spectra of CuS prepared at 180 °C for different times were studied. The possible transfer mechanism from wrapped nanowires to hollow spheres was suggested.     

Laurus nobilis L. oil as green corrosion inhibitor for aluminium and AA5754 aluminium alloy in 3% NaCl solution

The influence of (30%, v/v) ethanolic solution of Laurus nobilis L. oil on the corrosion inhibition of aluminium and AA5754 aluminium alloy in 3% NaCl solution was studied by weight loss method, potentiodynamic polarization, and linear polarization method. The polarization measurements show that addition of this oil in concentrations ranging from 10 ppm to 50 ppm induces a decrease of cathodic currents densities. The results confirm that AA5754 alloy has better corrosion resistance in 3% NaCl solution than pure aluminium, while the oil investigated has better inhibition action on corrosion process of pure aluminium. The surface analysis via SEM techniques indicate that the active molecules from L. nobilis L. oil absolutely retard the pitting corrosion on the specimen surfaces.     

Synthesis of polyaniline nanorods using sucrose stearate as soft template

Highly ordered polyaniline (PANI) nanorods were prepared by oxidative polymerization in the presence of sucrose stearate surfactant acting as a soft template and acetone as solvent. The polymerized PANI nanorods were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy, and X-ray diffraction (XRD). Results showed that the concentration of sucrose stearate exhibited a strong influence on nanorods diameters, surfaces, and also the crystallinity of PANI. The diameters and crystallinity increase remarkably with increasing the sucrose stearate concentration. A mechanism for the formation of nanorods is also proposed. The steric hindrance of sucrose stearate molecules and hydrogen bonds formed between sucrose stearate and anilium ions or oligomers molecules play an important part in the formation of PANI nanorods.     

Preparation and characterization of nanocrystalline Nd-YAG powder

Nanocrystalline materials have assumed notable importance in a wide variety of fields owing to numerous possible applications offered by them. These include transparent ceramics wherein they facilitate synthesis as well as sintering at significantly lower temperatures. We report preparation of nanocrystalline neodymium doped yttrium aluminum garnet (YAG) with an ultimate intent to make transparent Nd-YAG ceramic. The Liquid Mix method employed involves mixing of metal nitrates with excess amounts of citric acid followed by dissolution and polymerization in ethylene glycol to form complex chelates. Amorphous powder obtained by firing of polymeric chelate compound at 400 °C permits formation of nanoparticles of Nd:YAG at as low a crystallization temperature as 920 °C as shown by the thermal analysis. Progressive evolution of well crystallized phase-pure YAG was studied by XRD of amorphous powders subjected to different calcination temperatures. Scanning electron microscopic (SEM) study of the crystalline material shows that particle size ranges between 50 and 100 nm.     

Synthesis of platinum nanoparticles on carbon aerogel by ambient pressure drying method

Platinum nanoparticles were successfully synthesized on porous carbon aerogel with narrow pore size distribution by ambient pressure drying method. Platinum doped carbon aerogels were synthesized by sol-gel polymerization of resorcinol with furfural in non aqueous medium followed by ambient pressure drying and pyrolysis of organic gel. These samples were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD) and Flow Chemisorption. TEM and XRD results showed that size of platinum nanoparticle varies between 2 and 5 nm depending on platinum loading and pyrolysis temperature. Hydrogen pulsed chemisorption showed 26.5% dispersion of platinum nanoparticles in carbon aerogel.     

Characterization of AgBiS2 nanostructured flowers produced by solvothermal reaction

AgBiS₂ nanostructured flowers were produced from CH₃COOAg, Bi(NO₃)₃.5H₂O and thiosemicarbazide (NH₂CSNHNH₂) using different solvents [ethylene glycol (EG), water (H₂O), polyethylene glycol with molecular weight of 200 (PEG200), and propylene glycol (PG)] in Teflon-lined stainless steel autoclaves. The phase and purity were detected using X-ray diffraction (XRD), controlled by the solvents. The product was purified AgBiS₂ produced by the 200 °C and 24 h reaction in EG, corresponding to selected area electron diffraction (SAED) and simulation patterns. Scanning and transmission electron microscopies (SEM and TEM) revealed the formation of nanostructured flowers — enlarged by the increase in the lengths of time and temperature. Their photoluminescence (PL) emissions were detected at the same wavelength of 382 nm (3.24 eV), although they were produced under different conditions.     

Preparation of expandable graphite with ultrasound irradiation

This article reports a new way to prepare expandable graphite with ultrasound irradiation. Flake graphite mixture and ultrasonic solvent were placed into a flask in the ultrasonic cleaning bath (nominal power of 500 W and 250 W) at room temperature. Ultrasonic time kept 60 min. After ultrasound irradiation, the expandable graphite was expanded at 900 °C to obtain the expanded graphite. The process of ultrasound irradiation is different from both electrochemistry intercalation and chemistry oxidation intercalation, but the properties of expandable graphite are similar. X-ray diffraction patterns are used to analyze the structure and confirm that the expandable graphite has been prepared. Scanning electron microscope images show the structure of expandable graphite and the existence of expanded graphite.     

Additive-free and time-saving microwave hydrothermal synthesis of hollow microspheres structured boehmite

In this study, by using Al₂(SO₄)₃ aqueous solution and urea as raw materials, hollow microspheres structured boehmite was successfully synthesized only after 30 min reaction time at 180 °C via an additive-free and time-saving microwave hydrothermal route. The final products were characterized by techniques of X-ray diffraction (XRD), transmission electronic microscope (TEM), scanning electron microscope (SEM) and Fourier transform infrared spectrometry (FTIR). To investigate its crystal form and morphology evolution process, samples subjected to different reaction durations were prepared and characterized. The pivotal influence factors on boehmite morphology, such as reaction temperature, dosage of urea and microwave power range were discussed based on the experiment facts.     

Mechanochemical synthesis and characterization of TiB2 and VB2 nanopowders

A novel method for the synthesis of transition-metal boride nanopowder has been developed using a mechanochemical reaction between LiBH₄, LiH and transition-metal chloride (TiCl₃ and VCl₃) by high energy ball milling. This method successfully produces TiB₂ and VB₂ particles dispersed within a soluble LiCl matrix. Subsequent washing with distilled water, ethanol and acetone to remove the LiCl matrix phase yields TiB₂ and VB₂ nanopowders of 15-60 nm particle size. From the X-ray diffraction patterns and high resolution transmission electron microscopy image, it is found that each particle is polycrystalline consisting of 3-5 nm crystallites. Neither particle nor crystallite size are increased significantly after heating at 680 °C.     

Transient solid-state production of nanostructured CuS flowers

CuS (hcp) with different morphologies was produced using a transient solid-state reaction by the direct flow of electricity through solids, containing 1:1 molar ratio of Cu:S powders, in a high vacuum system for different lengths of time. X-ray diffraction (XRD), selected area electron diffraction (SAED), and scanning and transmission electron microscopies (SEM and TEM) specified that the products were nanostructured CuS flowers, and nanostructured CuS composing of nanoparticles with different orientations, controlled by the length of time. Raman vibrations were detected at 474.5 cm^− 1, and photoluminescent (PL) emissions at 347.5 nm. Both the XRD and SAED patterns are in accordance with those obtained by the corresponding simulations.     

Effect of carbon steel microstructure and molecular structure of two new Schiff base compounds on inhibition performance in 1 M HCl solution by DC,SEM and XRD studies

In this investigation, attempts have been made to study the inhibitive effect of N,N′-ortho-phenylen acetyle acetone imine (S1) and 4-[(3-{[1-(2-hydroxy phenyl) methylidene] amino} propyl) ethanemidol]-1,3-benzenediol (S2) in the concentration range of 50–400 ppm for mild steel with two different microstructures resulted from two different heat treatments (annealed (A) and quenched and tempered (Q&T)) in 1 M hydrochloric acid solution. Both Schiff bases acted as a mixed type inhibitors. The S1 inhibitor for both microstructures showed better inhibition efficiency than S2. The A samples indicated slightly less corrosion than Q&T samples in 1 M HCl solution in absence of inhibitor due to the formation of duplex γ-Fe₂O₃/Fe₃O₄.     

石墨烯和氧化石墨烯水基润滑添加剂在镁合金冷轧中的摩擦学行为EI北大核心CSCD

选用石墨烯和氧化石墨烯作为水基润滑添加剂,对比研究两种纳米材料对AZ31镁合金在冷轧过程中的摩擦学性能的影响。采用场发射扫描电镜(FESEM)和拉曼光谱仪(Raman)对石墨烯和氧化石墨烯水基润滑液润滑条件下轧后板材表面形貌和成分进行了分析,探讨了石墨烯和氧化石墨烯作为水基润滑添加剂的润滑机理。结果表明,石墨烯和氧化石墨烯在水中最优含量为0.5%(质量分数),摩擦因数分别为0.132和0.038,磨损体积分别为23.1 mm^3和2.59 mm^3。同时氧化石墨烯水基润滑液优良的润滑性能降低了镁合金轧制过程中的轧制力,改善了轧后板材表面质量。相同测试条件下,氧化石墨烯水基润滑液的润滑性能优于石墨烯水基润滑液,主要原因是其在水中良好的分散性和在镁合金表面优异的润湿性。