Lubricants
·
2022
·Vol. 10
·期 10
·260
·
IF 3.584
Hua Jiang,Xianjun Hou,Yuxin Ma,Weiwei Guan,Haijun Liu,Yucong Qian
This study conducted a tribological investigation of base oil (PAO6 and 5W 40) and ionic liquids (IL)-modified lubricants through a four-ball tribometer for 30 min. The lubricants were fabricated via a two-step method using stirring magnetic and ultrasonic dispersion. IL, base oil, and lubricants were, respectively, characterized by XRD and FTIR analysis. In addition, multiple characterizations such as EDS, 3D morphology, and SEM were carried out to evaluate the wear and friction performance of steel balls. Ultimately, the results showed that the coefficient of friction (COF) and wear scar diameter (WSD) of wear scar lubricated by IL-modified lubricants were greatly decreased than that by base oil. IL can well improve the tribological properties of PAO 6 oil and 5W-40 oil due to the tribo-film appearance on the friction surface of wear scar by the effective role of IL. Fascinatingly, this investigation comprehensively and elaborately put a new sight into the lubrication mechanism of how IL reacted with a base oil and enhanced the tribological characteristics.
研究领域:
材料科学
·
机械工程
✓ 已验证
DOI
高影响因子
OPTIK
·
2021
·
IF 2.443
Baili Chen,Wei Zhou,Mingshi Zhao,Pengchao Si
Silver nanostructure has excellent surface-enhanced Raman scattering (SERS) properties. However, the influence of the diameter of silver nanowires on the SERS is still unclear. To this end, four Ag NWs with diameters of 20, 25, 31, and 38 nm were designed and fabricated. The effects of diameter on the SERS were studied experimentally and simulated theoretically. The results indicate that the SERS activities of the Ag NWs increase with the diameter within a certain range. The highest EF value is up to 5.0 × 10 9 . These results may provide a reference for the design of high-performance Ag NWs SERS substrates.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2018
·Vol. 28
·期 11
·1705516
·
IF 13.325
Ximin Cui,Feng Qin,Qifeng Ruan,Xiaolu Zhuo,Jianfang Wang
2D or pseudo-2D plasmonic Au nanocrystals, such as circular Au nanodisks, possess unique plasmonic properties. Circular Au nanodisks not only possess two large surfaces with circular symmetry but also exhibit the wide tunability for their plasmon resonance. However, the lack of effective synthetic methods for producing size-tunable and monodispersed circular Au nanodisks hinders further studies on their properties and applications. Herein, the synthesis of uniformly sized circular Au nanodisks with synthetically tunable diameters and thicknesses is reported. By performing mild anisotropic oxidation on pregrown Au nanoplates with different thicknesses, the thicknesses of the obtained nanodisks are varied from ≈10 nm to ≈50 nm. The nanodisk diameters are tailored from ≈50 nm to ≈150 nm by controlling the oxidation time. Moreover, both homodimers and heterodimers made of circular Au nanodisks are constructed using molecular linkers. They exhibit rich plasmon modes. In particular, dark multipolar plasmon resonance modes can be excited and observed in the asymmetric heterodimers. Such circular Au nanodisks with controllable sizes, large atomically flat surfaces, and a dominant dipolar plasmon mode are ideal building blocks for constructing plasmonic assemblies and plasmon-coupled systems with desired plasmonic properties and functions.
研究领域:
材料科学
·
纳米技术
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 138
·期 4
·49734
·
IF 2.52
Qirui Yi,Jingyu Li,Runhua Zhang,Erni Ma,Ru Liu
Small particle diameter thermally expandable microspheres (TEMs) were obtained for potential utilization in wood, with special attention on their particle diameters and expansion properties. The revolving speed of homogenization (RS) of 800 ~ 3000 r min −1 was applied in suspension polymerization under atmospheric pressure to prepare TEMs, with n -hexane as core material and the copolymer of acrylonitrile, methyl acrylate, and vinyl acetate as shell. (a) The effect of the RS on the particle diameters of TEMs presented a negative correlation at low RS and remained stable at high RS, (b) When the RS was 1900 ~ 2100 r min −1 , the optimized TEMs with average particle diameters of 3.82 ~ 4.06 μm were prepared, possessing expansion ratios of 3.4 ~ 4.3 and an expansion temperature of 112°C, (c)The optimized TEMs had core-shell structure and high encapsulated content of alkane, and (d) The TEMs with small particle diameters could be impregnated into wood and expand successfully in wood cell lumens.
研究领域:
材料科学
·
林业工程
✓ 已验证
DOI
高影响因子
POLYMER
·
2025
·
IF 4.5
Chunhua Li,Yifu Ruan,GengXin Liu
Polymeric soft-nanoparticles (SNPs) synthesized via microemulsion polymerization, are widely used in both academia and industry. However, achieving a significantly smaller diameter still presents a challenge. Despite the use of excess surfactants, surface tension constraints prevent microemulsion droplets from decreasing in diameter below 20 nm. Still using conventional surfactants, we introduce a simple and efficient method for mass production of SNPs down to 10–15 nm in diameter. The microemulsion is prepared by incorporating solvents that are good for both monomers and polymers. This method effectively yields significantly smaller SNPs. In the melts of such small SNPs, the Rouse-like viscous-dominant behavior is observed and fully mapped with respect to the diameter and degree of cross-linking. This was previously not observed in microemulsion polymerized SNPs. We assess the cold flow conditions by determining the ability to form transparent sheets from the powder at room temperature when subjected to pressure. It is governed by the diameter and degree of crosslinking. The ultrasmall SNPs thus have the potential to be used as fillers in various industries.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ULTRASONICS SONOCHEMISTRY
·
2021
·
IF 7.491
Ningning Ouyang,Haile Ma,Yanhua Ding,Feng Lu,Lina Guo,Xueli Zhang,Chen Gu
A highly hygienic walnut emulsion beverage was prepared by using a slit dual-frequency emulsification technique. The optimal ultrasonic parameters were studied as a model system: the ultrasonic time of 50 min, the ultrasonic power density of 260 W/L, and a dual-frequency ultrasonic combination of 28/68 kHz. Walnut emulsion with an average mean volume diameter of 2.05 µm, a Zeta potential absolute value of 40 mV was obtained after ultrasonic treatment, and the emulsion stability could be maintained for more than 14 days without phase separation. At the lowest ultrasonic energy input, the vibrating emulsion could promote droplet aggregation. However, excessive energy input could result in sample overtreatment and reduced emulsion activity. The laser scanning confocal microscope (LSCM) and transmission electron microscope (TEM) confirmed that walnut emulsion processed by slit dual-frequency ultrasonic had pretty high stability. Therefore, the slit dual-frequency ultrasonic emulsification technique was found to be well suited for the preparation of complex and fine oil-in-water food emulsions.
研究领域:
食品科学
·
超声技术
·
物理化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Polymers
·
2019
·Vol. 11
·期 10
·1550
·
IF 3.164
Zhen Li,Shunqi Mei,Yajie Dong,Fenghua She,Lingxue Kong
While electrospinning has been widely employed to spin nanofibers, its low production rate has limited its potential for industrial applications. Comparing with electrospinning, centrifugal spinning technology is a prospective method to fabricate nanofibers with high productivity. In the current study, key parameters of the centrifugal spinning system, including concentration, rotational speed, nozzle diameter and nozzle length, were studied to control fiber diameter. An empirical model was established to determine the final diameters of nanofibers via controlling various parameters of the centrifugal spinning process. The empirical model was validated via fabrication of carboxylated chitosan (CCS) and polyethylene oxide (PEO) composite nanofibers. DSC and TGA illustrated that the thermal properties of CCS/PEO nanofibers were stable, while FTIR-ATR indicated that the chemical structures of CCS and PEO were unchanged during composite fabrication. The empirical model could provide an insight into the fabrication of nanofibers with desired uniform diameters as potential biomedical materials. This study demonstrated that centrifugal spinning could be an alternative method for the fabrication of uniform nanofibers with high yield.Keywords:carboxylated chitosan;centrifugal spinning;nanofiber diameter;empirical model
研究领域:
生物材料学
·
医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF FOOD ENGINEERING
·
2022
·
IF 6.203
Yihang Zhang,Jing Guo,Fucheng Guan,Jun Tian,Zheng Li,Sen Zhang,Miao Zhao
The preparation of nanofibers by electrospinning of food gum has been a challenge. Here, we reported a strategy for preparing narrow nanofibers by reducing the surface tension and enhancing the conductivity of “low concentration and high viscosity” food gum solution. The addition of cetyl trimethyl ammonium bromide (CTAB) improved the spinnability of guar gum (GG), propylene glycol alginate (PGA), and Gleditsia Sinensis lam gum (GSLG) solutions, allowing them to form Taylor cones during electrospinning, while volume shrinkage was activated with a higher solvent evaporation rate to reduce fiber diameter. Besides, based on fiber diameter, solution properties, and electrospinning setting, we proposed a kinetic model of fiber diameter. Scanning electron microscopy (SEM) showed that the average diameters of the fibers were 110, 90, and 100 nm for GG/CTAB, PGA/CTAB, and GSLG/CTAB, respectively. Correspondingly, the theoretical diameters of the kinetic models were 117.4, 102.4, and 109.6 nm, respectively, verifying the accuracy of the kinetic model.
研究领域:
食品科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Hong Wang,Sha Zhu,Zhanshuo Dai,Xinze Li,Taigang Zhou
Selective synthesis of large diameter single-walled carbon nanotubes (SWCNTs) is desired for a variety of applications, but most catalysts can only synthesize SWCNTs with a diameter less than 2 nm. Here, a low cost and green catalyst (Co/RH-SiO 2 ) was prepared by using rice husk-derived SiO 2 as the catalyst support, which selectively synthesized large SWCNTs (d t > 2 nm) with a percentage of 70.7 % among all tubes grown at the high growth temperature of 950 ℃. The carbon yield produced on this catalyst containing 1 wt% Co was 4.49 wt%. In contrast, commercial SiO 2 supported Co catalyst (Co/Cab-SiO 2 ) synthesized smaller SWCNTs with a broad diameter distribution under the same growth condition. The detailed characterizations of catalysts showed that Co/RH-SiO 2 catalyst is unique with the abundant small mesopores (2–4 nm) and reducible Co hydrosilicate and surface Co silicates highly dispersed in the pore structures. The reduction of Co hydrosilicate and surface Co silicates facilitates the formation of large Co clusters, which are stabilized by irreducible Co silicates and small mesopores, leading to the growth of large-diameter SWCNTs. Results in this study provide useful insights to develop low cost and green catalysts from biomass waste for the selective growth of SWCNTs.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 38
·e52903
·
IF 3.057
Han Wang,Liang Feng,Jun Zeng,Lingmin Chen,An Chen,Maolin Liu,Jingang Xiong
Nanofiber is a kind of high-performance material, which has great applications. Among many preparation methods, centrifugal electrospinning combines the advantages of electrospinning and centrifugal spinning, with high yield and a wide range of application. But its influencing factors are numerous, the process is still immature, and unable to meet the needs of industrialization. Here, we design a set of centrifugal electrospinning equipment and its process, and explore the influence of rotor form on fiber formation. First, the structure and working principle of experimental equipment of centrifugal electrospinning are introduced. Then, the influence of two factors, the rotor shape and rotor material, on space electric field is studied through theoretical and simulation analysis. Finally, based on the designed equipment, the effects of different rotor forms on the fibers preparation of centrifugal electrospinning are studied. The results show that the fiber diameter of centrifugal electrospinning is greatly affected by the form of the rotor. By changing the surface shape of the rotor and the rotor material, the diameter of the fiber can be controlled. Experiments show that the average fiber diameter of the γ-shaped rotor is the smallest, and the fiber spun with ULTEM PEI 1010 material has the best overall performance.
研究领域:
材料科学
·
纳米技术
✓ 已验证
DOI
高影响因子
ChemSusChem
·
2019
·Vol. 13
·期 4
·803-810
·
IF 7.804
Chengyi Zhu,Yannan Zhang,Xiaohua Yu,Peng Dong,Jianguo Duan,Jiaming Liu,Jianxiong Liu,Yingjie Zhang
Graphical Progress towards the positive : A facile strategy through manipulating KMnO 4 concentration is introduced to precisely fabricate 1 D LiMn 2 O 4 nanorods with four distinct diameter gradients. The LiMn 2 O 4 nanorod with a critical diameter of approximately 70–80 nm displays the highest discharge capacity and promising cycling performance. The role of 1 D crystal size in effecting interface chemical species and electrochemical performance is elucidated by comparative characterization methods. The morphology and size of nanoelectrode materials determine their properties. Compared to the bulk structure electrodes, 1 D electrode materials for Li-ion batteries have been intensively studied owing to their excellent Li + diffusion kinetics. It is generally accepted that smaller-sized electrode materials lead to better Li storage kinetics. In this study, this is found to not be the case in 1 D LiMn 2 O 4 positive materials. A facile strategy of manipulating the KMnO 4 concentration is introduced to precisely fabricate 1 D LiMn 2 O 4 nanorods with four distinct diameter gradients from 30 to 170 nm. The role of 1 D crystal size in effecting interface chemical species and electrochemical performance is elucidated by comparative characterization methods. X-ray photoelectron spectroscopy (XPS) Ar-ion etching technology shows that the Mn 2+ is electrochemically inactive on the surface of the sample, which explains the adverse effects observed on LiMn 2 O 4 nanorods with the minimum diameter of 30–40 nm, such as decreased discharge capacity. The LiMn 2 O 4 nanorod with a critical diameter of approximately 70–80 nm displays the highest discharge capacity and promising cycling performance. This work clarifies an important property that has previously been neglected and deepens the understanding for design of Mn-based positive materials.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF PHARMACEUTICAL SCIENCES
·
2023
·
IF 3.8
Ya Xu,Huiyang Li,Nan Sun,Bingmei Yao,Wenjin Dai,Jian Wang,Sujia Si,Shuo Liu,Liqun Jiang
Background High Altitude Pulmonary Edema (HAPE) seriously threatens the health of people at high altitudes. There are drug treatments for HAPE, and dry powder formulations (DPFs) represent a rapid and accessible delivery vehicle for these drugs. However, there are presently no reports on the inhalability of DPFs in low-pressure environments. Given the reduced atmospheric pressure typical at high altitudes, conventional DPFs might not be suitable for inhalation. Therefore, it is necessary to elucidate the deposition behaviors of dry powder in the respiratory tract at low pressure, as well as to improve their pulmonary deposition efficiency via adjustments to their formulation and design. Methods The effect of air pressure, inspiratory velocity, and particle properties (such as size, density, and aerodynamic diameter) on pulmonary deposition of DPFs was calculated by a computational fluid dynamics (CFD)-coupled discrete phase model. DPFs of various aerodynamic diameters were prepared by spray drying, and the inhalability of these DPFs in a low-pressure environment was evaluated in mice. Finally, a mouse model of HAPE was established, and the treatment of HAPE by nifedipine-loaded DPFs with small aerodynamic diameter was validated. Results CFD results showed that low pressure decreased the deposition of DPFs in the lungs. At 0.5 standard atmosphere, DPFs with aerodynamic diameter of ∼2.0 μm could not enter the lower respiratory tract; however, a decrease in the physical diameter, density, and, consequently, the aerodynamic diameter of the DPFs was able to enhance pulmonary deposition of these powders. To validate the CFD results, three kinds of dry powder with aerodynamic diameters of 0.66, 0.98, and 2.00 μm were prepared by spray drying. Powders with smaller aerodynamic diameter could be inhaled into the lungs of mice more effectively, and, consequently could ameliorate the progression of HAPE more effectively than conventional powders. These results were consistent with the CFD results. Conclusions Low atmospheric pressure can prevent the pulmonary deposition of DPFs at high altitudes. Compared with conventional DPFs, powders with smaller aerodynamic diameter can be effectively inhaled at these pressures and thus might be more suitable for the treatment the HAPE.
研究领域:
药剂学
·
呼吸病学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）