纳米SiO2在提高采收率与降压增注中的应用进展

纳米技术现已广泛应用于生物、医药、材料等多个领域,在石油勘探开发领域也具有诸多潜在应用价值.综述了纳米颗粒在石油开发领域中提高采收率及降压增注的应用进展,石油开发所使用的纳米颗粒可分为金属纳米颗粒、有机纳米颗粒、无机纳米颗粒;针对表面改性后纳米SiO2分散性变差的问题介绍了新型生物表面活性剂等纳米材料分散方法;纳米SiO2提高采收率的主要机理是楔形挤压、润湿反转、降低界面张力及其他提采机理;纳米SiO2降压增注机理为进入地层后形成的疏水膜能改变润湿性、防止黏土膨胀,对于吸附纳米颗粒能否增大孔道半径存在争议.建议今后从纳米SiO2地层匹配性、降压增注解析模型、数值模拟模型以及生物基表面活性剂开展相关的技术研究.     

Gold nanorod translocation through a solid-state nanopore

Recently, nanopores have been used in an essential technique for detecting single molecule with high sensitivity. The initial application of nanopores to DNA and RNA sequencing has been expanded to sensing pro- teins and nanoparticles, including Bovine serum albumin, silica nanoparticles, polystyrene beads, and others. In our study, for the first time, a positively charged gold nanorod was investigated using a solid-state nanopore device. Various gold nanorods passed through the nanopore with different current blockages and duration times, providing a measurement of the nanorod diameter, length, and charge. Our findings indicate that nanopore sensing might be a new method for characterizing the size, shape, and charge of nanoparticles.     

Formation of highly crystalline maghemite nanoparticles from ferrihydrite in the liquid phase

Fe5O7（OH）·4H2O ferrihydrite is a low-crystal- linity antiferromagnetic material, γ-Fe2O3 （maghemite） magnetic nanoparticles were prepared from a ferrihydrite precursor, by chemically induced transformation in FeCl2/ NaOH solution. The magnetization, morphology, crystal structure and chemical composition of the products were determined by vibrating sample magnetometry, transmission electron microscopy, X-ray diffraction （XRD）, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy （XPS）. Ferrihydrite underwent aggregation growth and transformed into α-FeO（OH） （goethite） particles, which subsequently transformed into γ-Fe2O3 nanoparticles, that became coated with NaCI. The γ-Fe2O3 particles had a flake-like morphology, when prepared from 0.01 mol/L FeCl2 and a FeCl2：NaOH molar ratio of 0.4. The γ-Fe2O3 particles were more spherical, when prepared from a FeCl2：NaOH molar ratio of 0.6. The Fe content of the flake-like particles was lower than that of the spherical particles. Their magnetizations were similar, and the coercivity of the flake-like particles was larger. The differences in morphology and magnetization were attributed to the surface effect, and the difference in coercivity to the shape effect.     

Nanoscale electron tomography and atomic scale high-resolution electron microscopy of nanoparticles and nanoclusters: A short survey

The outstanding merits of scanning transmission electron tomography as a technique for the investigation of the internal structure and morphology of nanoparticle and nanocluster materials are summarized with the aid of numerous typical illustrations.Reference is made also to the significant advances that have arisen in probing ultrastructural characteristics of nanoscale solids using aberrationcorrected(AC) electron microscopy(EM).Information of a unique kind may be retrieved by combining the imaging and analytical power of ACEM.     

正交试验法优化阿昔洛韦固体纳米粒的处方

采用正交试验法筛选阿昔洛韦固体脂质纳米粒最优处方。利用(W/O/W)复乳-超声法制备阿昔洛韦固体脂质纳米粒,以包封率为评价指标,采用L9(34)正交试验设计筛选出最优处方。单硬脂酸甘油酯用量1.5%、大豆卵磷脂用量0.4%、泊洛沙姆188浓度2%、油相与内水相体积比(Vo/V)i 6。正交试验优化阿昔洛韦固体纳米粒处方有效、可行。     

Evaluation of charge storage ability of chrome doped Mn2O3 nanostructures derived by cathodic electrodeposition

A facile synthetic route has been proposed to prepare cauliflower-like nanostructures of Cr doped Mn2O3. The synthesis was carried out by constant current cathodic electrodeposition from Mn2+ nitrate solutions containing minor amounts of dichromate. It was found that the presence of Cr mediates the formation of cathodic MnO2 which then reacts with the excess Mn2+ species to form Mn2O3 nanostructures. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Differential Thermal Analysis (DTA) were used to characterize the nanostructures. The storage ability of the obtained nanostructures was investigated by cyclic voltammetry (CV) in 0.5 M Na2SO4 solution. The results indicated that the Cr doped manganese oxide material shows better performance than the non-doped one, and the charge capacity (SC) of doped manganese oxide (218 F/g) was higher than pure manganese oxide (208 F/g).     

Chiral supramolecular gold-cysteine nanoparticles: Chiroptical and nonlinear optical properties

Cysteine is a sulfur-containing amino acid that easily coordinates to soft metal ions and grafts to noble metal surfaces. We report a simple synthetic approach for the production of chiral gold-cysteine polymeric nanoparticles soluble in water. Conjugation of cysteine with gold in a polymeric way, leading to ~50 nm diameter nanoparticles, resulted in the generation of new characteristic circular dichroism (CD) signals in the region of 250–400 nm, whereas no CD signal changes were found with cysteine alone. We also investigate their nonlinear optical properties after two-photon absorption. Two-photon emission spectra and first hyper-polarizabilities, as obtained by the hyper-Rayleigh scattering technique, of these particles are presented.     

Role of β(FeAl) nanoparticles in abnormal grain growth in the annealing of cast Cu-Al-Mn-Fe shape memory alloys

In this study, the low-cost production of Cu-Al-Mn-Fe shape memory alloy single crystals exceeding 46 mm by abnormal grain growth was realized only through annealing their cast alloys. The results show that the misorientation formed during annealing may be responsible for such abnormal grain growth process. It was confirmed that this misorientation resulted from the dissolution of bcc β(FeAl) nanoparticles during heat treatment at a sufficiently temperature of approximately 1173 K. The rate of migration of the abnormal grain boundary was experimentally measured to be approximately 9.3 × 10^-5 m s^-1 within 2 min of the commencement of abnormal grain growth. Additionally, the range of composition of the alloys that can lead to abnormal grain growth was determined. When the Cu-13.0Al-6.5Mn-3.2Fe single crystal close to the [100] direction was deformed to a pre-strain of 12%, full shape recovery happened without any residual strain. At that time, the superelastic strain was approximately 9%. Such a superelastic characteristic remained nearly constant over 50 cycles, showing excellent fatigue resistance. The superelastic properties of the present Cu-13.0Al-6.5Mn-3.2Fe single crystal are compared to those of commercial Ni-Ti-based shape memory alloys. Therefore, it can be considered as a new kind of superelastic material having practical applications. The obtained results should be of great significance in the development of Cu-based shape memory alloys. Furthermore, it is expected that a similar microstructure can be designed for the production of more metallic single crystals.     

Fe3O4@C nanoparticles as high-performance Fenton-like catalyst for dye decoloration

Water pollution has become serious environmental problem nowadays. Advanced oxidation processes(AOP) have been widely applied in water treatment.However, traditional Fenton reaction based on Fe2﹢-H2O2 system has obvious drawbacks, which limit its applications In this study, magnetic Fe3O4core-C shell nanoparticles(Fe3O4@C NPs) were prepared for the decoloration of methylene blue(MB) via the co-precipitation followed by the hydrothermal dehydrogenation of glucose. Fe3O4@C NPs showed high catalytic activity of the decoloration of MB through the decomposition of H2O2 in Fenton-like reactions. Fe3O4@C NPs had much higher activity than bare Fe3O4 cores, suggesting the coating of carbon enhanced the catalytic activity. The performance of Fe3O4@C NPs was better at lower pH and higher temperature, but was significantly inhibited in the presence of radical scavenger tertiary butanol. Fe3O4@C NPs could be magnetic separated and regenerated, and maintained with very good catalytic activity. The implication for the applications of Fe3O4@C NP-catalyzed Fenton-like reactions in water treatment was discussed.     

Pulmonary toxicity induced by three forms of titanium dioxide nanoparticles via intra-tracheal instillation in rats

Titanium dioxide (TiO2) nanoparticles are in wide commercial use worldwide. To evaluate if acute pulmonary toxicity can be induced by nano-TiO2 particles, rats were intra-tracheally instilled with 0.5, 5, or 50 mg/kg of 5, 21, and 50 nm TiO2 primary particles. Toxic effects were determined with the coefficients of lung tissues to body weight, histopathology, biochemical parameters of blood, activity of lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and acid phosphatase (ACP) in tissues, and the phagocytotic ability of alveolar macrophages (AMs). All the indicators were observed in sacrificed rats one week post-exposure. There was a significant difference of coefficients of pulmonary tissues between the high-dose group and the low- or moderate-dose groups with an exposure of 5 nm TiO2. At the same time, 5 nm TiO2 primary particles increased the activity of LDH and ALP when exposure dose was >5 mg/kg. A significant difference in LDH and ALP activity was observed between the 50 mg/kg group and 0.5 or 5 mg/kg group with exposure of 5 nm TiO2. Lung tissues showed increased ALP activity only if treated with 5 and 50 mg/kg of 21 nm TiO2 particles. There was no significant difference in LDH and ALP activity in the 50 nm TiO2 group and control group. Histopathologic examination of lung tissues indicated that the pulmonary response to exposure to TiO2 particles in rats manifested as dosedependent inflammatory lesions, which mainly consisted of infiltration of inflammatory cells and interstitial thickening. Analysis of uptake of neutral red dye showed that 50 nm TiO2 particles significantly increased phagocytotic ability of AMs compared with controls (P < 0.05), whereas exposure with 5 nm TiO2 reduced the phagocytotic ability of AMs when the exposure dose was 50 mg/kg. These results suggest that particle size and exposure dose may have important roles in pulmonary toxicity. The toxic effect of TiO2 nanoparticles in lung tissue exhibited a dose–response relationship. After exposure with TiO2 particles of >5.0 mg/kg, 5 and 21 nm TiO2 particles induced standing pulmonary lesions; and 5 nm TiO2 particles may suppress the phagocytotic ability of AMs if exposure dose was ≥50 mg/kg. Pulmonary toxicity caused by 5 nm TiO2 particles was more severe than that caused by 21 and 50 nm TiO2 particles.