Rolling contact fatigue performance is among the most important issues for applications of bearing steels.In this work,a recently developed surface modification technique,surface mechanical rolling treatment,was appli...Rolling contact fatigue performance is among the most important issues for applications of bearing steels.In this work,a recently developed surface modification technique,surface mechanical rolling treatment,was applied on a rare-earth addition bearing steel.And rolling contact fatigue behavior of treated samples was compared with that of as-received counterparts at different contacting stresses.The results demonstrated that a 700μm-thick gradient nanostructured surface layer is produced on samples by surface mechanical rolling treatment.The grain size decreases while the microhardness increases gradually with decreasing depth,reaching~23 nm and~10.2 GPa,respectively,at the top surface.Consequently,the rolling contact fatigue property is significantly enhanced.The characteristic life of treated samples is~3.2 times that of untreated counterparts according to Weibull curves at 5.6 GPa.Analyses of fatigue mechanisms demonstrated that the gradient nanostructured surface layer might not only retard material degradation and microcrack formation,but also prolong the steady-state elastic response stage under rolling contact fatigue.展开更多
1.Introduction The synthesis of bulk nanostructured multiphase(NM)mate-rials with extreme properties such as high hardness and strength is one of the most interesting research topics in materials science and engineeri...1.Introduction The synthesis of bulk nanostructured multiphase(NM)mate-rials with extreme properties such as high hardness and strength is one of the most interesting research topics in materials science and engineering[1].At present,NM alloys can be produced by several synthesis methods,including sintering of nanocomposites[2,3],physical or chemical vapour deposition(PVD or CVD)[4],crystallization of metallic glasses[5],and severe plastic deforma-tion(SPD)[6-8].However,industry applications of bulk NM alloys produced by these methods are significantly restricted by their ge-ometrical and size limitations.Thus,the fabrication of large-scale NM alloys remains challenging.展开更多
High porosity and high brittleness are the main reasons that limit the long-term service life of the alumina-titanium oxide composite coating.Herein,a metastable nanostructured aluminatitanium oxide composite coating ...High porosity and high brittleness are the main reasons that limit the long-term service life of the alumina-titanium oxide composite coating.Herein,a metastable nanostructured aluminatitanium oxide composite coating with high density and high properties was synthesized by plasma spraying of TiO_(2)-Al composite powder.The main phases of the metastable nanostructured alumina-titanium oxide wereγ-Al_(2)O_(3),TiO and AlTiO_(2).The coating,as prepared,contains various metastable microstructures,such as fine-grained,intra-/inter-granular,and"self-locking"microstructures.These metastable microstruc-tures are important for the improvement of hardness and toughness of the coating.Compared with other alumina-based composite coatings,the metastable nanostructured aluminatitanium oxide composite coating showed the most impressive overall performance.The reinforcing and toughening mechanism of the metastable alumina-titanium oxide composite coating included fine grain strengthening and self-toughening of the metastable microstructure.展开更多
High-pressure β-Sn germanium may transform into diverse metastable allotropes with distinctive nanostructures and unique physical properties via multiple pathways under decompression.However,the mechanism and transit...High-pressure β-Sn germanium may transform into diverse metastable allotropes with distinctive nanostructures and unique physical properties via multiple pathways under decompression.However,the mechanism and transition kinetics remain poorly understood.Here,we investigate the formation of metastable phases and nanostructures in germanium via controllable transition pathways of β-Sn Ge under rapid decompression at different rates.High-resolution transmission electron microscopy reveals three distinct metastable phases with the distinctive nanostructures:an almost perfect st12 Ge crystal,nanosized bc8/r8 structures with amorphous boundaries,and amorphous Ge with nanosized clusters (0.8–2.5 nm).Fast in situ x-ray diffraction and x-ray absorption measurements indicate that these nanostructured products form in certain pressure regions via distinct kinetic pathways and are strongly correlated with nucleation rates and electronic transitions mediated by compression rate,temperature,and stress.This work provides deep insight into the controllable synthesis of metastable materials with unique crystal symmetries and nanostructures for potential applications.展开更多
This study introduces a nanostructured MgO coating fabricated via anodization in a non-aqueous electrolyte,offering a novel approach to addressing the challenges of corrosion resistance and biofunctionality.The surfac...This study introduces a nanostructured MgO coating fabricated via anodization in a non-aqueous electrolyte,offering a novel approach to addressing the challenges of corrosion resistance and biofunctionality.The surface was characterized before and after immersion testing using field emission scanning electron microscopy(FESEM),energy-dispersive X-ray spectroscopy(EDX),and X-ray diffraction(XRD).Electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization tests demonstrated a 2-fold reduction in the corrosion resistance compared to untreated magnesium.Biomineralization studies demonstrated the uniform formation of apatite with a Ca/P ratio of 1.35 on the nanostructured surface after 14 days in simulated body fluid(SBF),surpassing that of microstructured MgO.Hydrogen evolution decreased from 912±38μL cm^(-2)for untreated Mg to 615±32μL cm^(-2)for the Mg/MgO nanostructure and 545±29μL cm^(-2)for the Mg/Mg O/HA sample.These findings highlight the potential of nanostructured MgO coatings to advance Mg-based implants by providing enhanced corrosion protection,improved biomineralization,reduced hemolysis and increased cell viability,and reduced H_(2)generation.展开更多
Solid oxide cells(SOCs)are attractive electrochemical energy conversion/storage technologies for electricity/green hydrogen production because of the high efficiencies,all-solid structure,and superb reversibility.Neve...Solid oxide cells(SOCs)are attractive electrochemical energy conversion/storage technologies for electricity/green hydrogen production because of the high efficiencies,all-solid structure,and superb reversibility.Nevertheless,the widespread applications of SOCs are remarkably restricted by the inferior stability and high material costs induced by the high operational temperatures(600-800℃).Tremendous research efforts have been devoted to suppressing the operating temperatures of SOCs to decrease the overall costs and enhance the long-term durability.However,fuel electrodes as key components in SOCs suffer from insufficient(electro)catalytic activity and inferior impurity tolerance/redox resistance at reduced temperatures.Nanostructures and relevant nanomaterials exhibit great potential to boost the performance of fuel electrodes for low-temperature(LT)-SOCs due to the unique surface/interface properties,enlarged active sites,and strong interaction.Herein,an in-time review about advances in the design and fabrication of nanostructured fuel electrodes for LT-SOCs is presented by emphasizing the crucial role of nanostructure construction in boosting the performance of fuel electrodes and the relevant/distinct material design strategies.The main achievements,remaining challenges,and research trends about the development of nanostructured fuel electrodes in LT-SOCs are also presented,aiming to offer important insights for the future development of energy storage/conversion technologies.展开更多
Phenylethyl resorcinol(PR)demonstrates inhibitory effects on multiple targets in the melanin synthesis pathway,resulting in a strong whitening effect.However,challenges such as limited solubility in water and suscepti...Phenylethyl resorcinol(PR)demonstrates inhibitory effects on multiple targets in the melanin synthesis pathway,resulting in a strong whitening effect.However,challenges such as limited solubility in water and susceptibility to oxidation and discoloration restrict its practical application in the cosmetics industry.In order to enhance stability and performance characteristics,a whitening nanostructured lipid carrier(NLC)was synthesized through high-pressure homogenization.This method entailed the incorporation of solid lipids,a liquid lipid,and a compound emulsifier,with deionized water fulfilling the roles of solid phase,liquid phase,and water phase,respectively.The NLC's particle size,Zeta potential,stability,encapsulation efficiency,and other parameters were assessed using techniques such as particle sizer,stability analyzer,and HPLC.The results showed that the NLC for phenylethyl resorcinol prepared by using the optimal formula(7.50%solid lipids,3.00%ethylhexyl palmitate,and 2.00%Tween 80 and soybean lecithin)has an encapsulation efficiency of 87.11%,a particle size of 157.2±0.70 nm,a kinetic instability of less than 1.2,and a greatly improved stability,thereby successfully solving the problems of unstable storage and poor solubility of phenylethyl resorcinol.展开更多
The Ni-based alloy composite coatings reinforced by nanostructured Al2O3-40%TiO2 multiphase ceramic particles were prepared on the surface of 7005 aluminum alloy by plasma spray technology. The microstructure and trib...The Ni-based alloy composite coatings reinforced by nanostructured Al2O3-40%TiO2 multiphase ceramic particles were prepared on the surface of 7005 aluminum alloy by plasma spray technology. The microstructure and tribological properties of the composite coatings were researched. The results show that the composite coatings mainly consist of γ-Ni, α-Al2O3, γ-Al2O3 and rutile-TiO2 etc, and exhibit lower friction coefficients and wear losses than the Ni-based alloy coatings at different loads and speeds. The composite coating bears low contact stress at 3 N and its wear mechanism is micro-cutting wear. As loads increase to 6-12 N, the contact stress is higher than the elastic limit stress of worn surface, and the wear mechanisms change into multi-plastic deformation wear, micro-brittle fracture wear and abrasive wear. With the increase of speeds, the contact temperature of worn surface increases. The composite coating experiences multi-plastic deformation wear, fatigue wear and adhesive wear.展开更多
The roots of 200 one-year-old Changbai Larch (Larix olgensis) seedlings were soaked for 6 hours at the TMS concentrations of 2000, 1000, 500, 250, 125, and 62 μL·L?1. Mean seedling height, root collar diameter, ...The roots of 200 one-year-old Changbai Larch (Larix olgensis) seedlings were soaked for 6 hours at the TMS concentrations of 2000, 1000, 500, 250, 125, and 62 μL·L?1. Mean seedling height, root collar diameter, main root length and number of lateral roots were measured every 15 days during growing season from May 30 to Oct. 20. Experimental results showed that TMS treatments greatly promoted seedling growth and improved seedling quality. The treatment by 500 μL·L?1 TMS produced the best result, for which the mean height, root collar diameter, main root length, and the number of lateral roots of seedlings were increased by 42.5%, 30.7%, 14.0%, and 31.6%, respectively, compared to that of the control seedlings. As to seedling quality, grade-I seedling and grade-II seedlings were fifty-fifty, and no grade-III seedlings was found. The treatment by 500 μL·L?1 TMS resulted in the highest chlorophyll concentration. Keywords Changbai Larch - Larix olgensis - Seedling production - Nanostructured silicon dioxide CLC number S143.8 Document code B Foundation item: This study is supported by Jilin Forestry Group Co.Biography: LIN Baoshan (1955-), male, Associate professor at the college of forestry, Beihua University, Jilin City 132011, Jilin Province, P.R China.Responsible editor: Chai Ruihai.展开更多
Artemisinin（ART） is a widely used active drug for malaria, including severe and cerebral malaria. However, its therapeutic efficacy is affected by its lower bioavailability. In the present study, nanostructured lipi...Artemisinin（ART） is a widely used active drug for malaria, including severe and cerebral malaria. However, its therapeutic efficacy is affected by its lower bioavailability. In the present study, nanostructured lipid carriers（NLCs） were proposed as carrier of ART to improve pharmacokinetic properties of the drug. ART-NLC was prepared by high-pressure homogenization based on orthogonal design. The particle size, zeta potential, encapsulation efficiency（EE） and percentage of drug loading（DL） of ART-NLC were（53.06±2.11） nm,（–28.7±3.59） m V, 73.9%±0.5% and 11.23%±0.37%, respectively. ART-NLC showed the sustained release characteristics and scarcely the hemolysis effect on human red blood cells. The pharmacokinetics of ART-NLC for rats after tail intravenous injection（i.v） or intraperitoneal injection（i.p） were investigated by liquid chromatography-tandem mass spectroscopy（LC-MS/MS）. And ART solution was designed as control preparation. For rats of i.v groups, the AUC0–∞（（707.45±145.65） ng·h/m L） of ART-NLC were significantly bigger than that of ART（（368.98±139.58） ng·h/m L）. The MRT（（3.38±0.46） h） of ART-NLC was longer than that of ART（（1.39±0.61） h）. And similar results were observed for rats of i.p groups. The AUC0–∞（（1233.06±235.57） ng·h/m L） and MRT（（4.97±0.69） h） of ART-NLC were both bigger than those of ART, which were（871.17±234.03） ng·h/m L） and（1.75±0.31） h）, respectively. Compared with ART, ART-NLC showed a significant increase in AUC0–∞（P〈0.05） and MRT（P〈0.001） for both i.p and tail i.v administrations.展开更多
Surface modification may have important influences on the penetration behavior of nanoscale drug delivery system. In the present study, we mainly focused on whether cell targeting or cell penetration could affect pene...Surface modification may have important influences on the penetration behavior of nanoscale drug delivery system. In the present study, we mainly focused on whether cell targeting or cell penetration could affect penetration abilities of nanostructured lipid carriers（NLC）. Real--time penetration of folate--or cell penetrating peptide（CPP）-modified NLC was evaluated using a multicellular tumor spheroid（MTS） established by stacking culture method as an in vitro testing platform. The results suggested that CPP modification had a better penetration behavior both on penetration depth and intensity compared with folate-modified NLC at the early stage of penetration process.展开更多
Bearings are the most important component of nearly all mechanical equipment, as they guarantee the steady running of the equipment, which is especially important for high-end equipment such as highspeed trains and sh...Bearings are the most important component of nearly all mechanical equipment, as they guarantee the steady running of the equipment, which is especially important for high-end equipment such as highspeed trains and shield tunneling machines. Requirements regarding the quality of bearings are increasing with the rapid development in technology. A country’s bearings manufacturing level directly reflects the level of that country’s steel metallurgy and machinery manufacturing. The performance of the bearing steel is the critical factor that determines the quality of a bearing. The development of new bearing steel with higher performance is the ambition of material researchers and the expectation of the manufacturing industry. Many famous bearing manufacturing enterprises are competing to develop the new generation of bearing steel. Nanostructured bainitic bearing steel (NBBS), which is a newly developed bearing steel, not only possesses high strength and toughness, but also exhibits excellent wear resistance and rolling contact fatigue (RCF) resistance. In recent years, relevant achievements in NBBS in China have led to significant progress in this field. NBBS was first used in China to manufacture large bearings for wind turbines and heavy-duty bearings, with excellent performance. As a result, NBBS and its corresponding heat-treatment process have been included in the national and industry standards for the first time. The bearing industry considers the exploitation of NBBS to be epoch-making, and has termed this kind of bearing as the second generation of bainitic bearing. In this paper, the development of NBBS is reviewed in detail, including its advantages and disadvantages. Further research directions for NBBS are also proposed.展开更多
The microstructure and wear performance of M203-13% TiO2 coatings prepared by plasma spraying of agglom- erated nanoparticle powders were investigated. SEM analysis showed that the as-sprayed Al2O3-TiO2 coatings compr...The microstructure and wear performance of M203-13% TiO2 coatings prepared by plasma spraying of agglom- erated nanoparticle powders were investigated. SEM analysis showed that the as-sprayed Al2O3-TiO2 coatings comprise of two kinds of typical region： fully melted region and unmelted/partially melted nanostructured region, which is different than the conventional coating with lamellar structure. It is shown that the microhardness of the nanostructured coatings was about 15%-30% higher than that of the conventional coating and the wear resistance is significantly improved, especially under a high wear load. The nanostructured coating sprayed at a lower power shows a lower wear resistance than the coatings produced at a higher power, because of the presence of pores and microstructural defects which are detrimental to the fracture toughness of the coatings.展开更多
Nanostructured Fe-doped titanium dioxide was synthesized from titanium containing electric furnace molten slag （TCEFMS） by using an alkali fusion, followed by a hydrolyzation-acidolysis-cMcination route. The effects...Nanostructured Fe-doped titanium dioxide was synthesized from titanium containing electric furnace molten slag （TCEFMS） by using an alkali fusion, followed by a hydrolyzation-acidolysis-cMcination route. The effects of Mkali/slag mass ratio, calcinating temperature, calcinating time, and water/slag mass ratio on the extraction efficiency and purity of products were systematically studied in this paper. It is indicated that the best extraction efficiency of nanostructured Fe- doped titanium dioxide is 99.35%, when the molten slag is calcinated at 700℃ for 1 h with the mass ratio of alkali/molten slag of 1.5：1. The influence of alkali/slag mass ratio on the photocatalytic activity of final products was evaluated by the photodegradation of methyl blue under visible light irradiation. A maximum photodegradation efficiency of 88.12% over 30 min was achieved under the optimum conditions.展开更多
Cerium-doped SiO2/TiO2 nanostructured fibers were fabricated by electrospinning technology. The prepared fibers were characterized by thermogravimetric analysis （TGA）, scanning electron microscopy （SEM）, X-ray dif...Cerium-doped SiO2/TiO2 nanostructured fibers were fabricated by electrospinning technology. The prepared fibers were characterized by thermogravimetric analysis （TGA）, scanning electron microscopy （SEM）, X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FT-IR）. Using the fibers as catalysts, photoeatalytic degradation of Methylene Blue （MB） aqueous solution was carded out under simulated sunlight. The 0.2% Ce doping proved to be the optimal concentration for the doping of TiO2/SiO2, compared to other Ce-doped molar concentrations. The 0.2% Ce-doped SiOdTiO2 fibers exhibited higher photocatalytic activity than industrial Degussa P25 and the samples doped with only Ce or SIO2. The reasons for improving the photocatalytic activity were also discussed. Several operational parameters were studied, which showed that the photocatalytic efficiency of MB was influenced by parameters such as the initial dye concentration, the initial pH, inorganic anions, and so on. In addition, the influences of an electron acceptor and a radical scavenger suggested that OH was the dominant photooxidant during the photocatalytic process. The reuse evaluation of the fibers indicated that their photocatalytic activity had good stability.展开更多
Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics device...Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.展开更多
The objective of this study was to prepare nanostructured lipid carrier(NLC)-based topical gel of Ganoderma Triterpenoids(GTs) and evaluate their effects on frostbite treatment. GT-NLCs was prepared by the high pressu...The objective of this study was to prepare nanostructured lipid carrier(NLC)-based topical gel of Ganoderma Triterpenoids(GTs) and evaluate their effects on frostbite treatment. GT-NLCs was prepared by the high pressure homogenization method and then characterized by morphology and analyses of particle size, zeta potential, entrapment efficiency(EE), and drug loading(DL). The NLCs was suitably gelled for skin permeation studies in vitro and pharmacodynamic evaluation in vivo, compared with the GT emulgel. The GT-NLC remained within the colloidal range and was uniformly dispersed after suitably gelled by carbopol preparation. Transmission electron microscopy(TEM) study showed GT-NLCs was spherical in shape. The EE(%) and DL(%) could reach up to(81.84 ± 0.60)% and(2.13 ± 0.12)%, respectively. The result of X-ray diffractograms(XRD) showed that GTs were in an amorphous state in the NLC-gel. In vitro permeation studies through rat skin indicated that the amount of GTs permeated through skin of GT-NLCs after 24 h was higher than that of GT emulsion, and GT-NLCs increased the accumulative amounts of GTs in epidermis 7.76 times greater than GT emulsion. GT-NLC-gel was found to possess superior therapeutic effect for frostbite, compared with the GT emulgel. The NLC based topical gel of GTs could improve-their therapeutic effect for frostbite.展开更多
Tissue engineering is promising to meet the increasing need for bone regeneration. Nanostructured calcium phosphate （CAP） biomaterials/scaffolds are of special interest as they share chemical/crystallographic simila...Tissue engineering is promising to meet the increasing need for bone regeneration. Nanostructured calcium phosphate （CAP） biomaterials/scaffolds are of special interest as they share chemical/crystallographic similarities to inorganic components of bone. Three applications of nano-CaP are discussed in this review： nanostructured calcium phosphate cement （CPC）; nano-CaP composites; and nano-CaP coatings. The interactions between stem cells and nano-CaP are highlighted, including cell attachment, orientation/ morphology, differentiation and in vivo bone regeneration. Several trends can be seen： （i） nano-CaP biomaterials support stem cell attachment/proliferation and induce osteogenic differentiation, in some cases even without osteogenic supplements; （ii） the influence of nano-CaP surface patterns on cell alignment is not prominent due to non-uniform distribution of nano-crystals; （iii） nano-CaP can achieve better bone regeneration than conventional CaP biomaterials; （iv） combining stem cells with nano-CaP accelerates bone regeneration, the effect of which can be further enhanced by growth factors; and （v） cell microencapsulation in nano-CaP scaffolds is promising for bone tissue engineering. These understandings would help researchers to further uncover the underlying mechanisms and interactions in nano-CaP stem cell constructs in vitro and in vivo, tailor nano-CaP composite construct design and stem cell type selection to enhance cell function and bone regeneration, and translate laboratory findings to clinical treatments.展开更多
The objective of this study was to develop a novel hybrid genipin-crosslinked dual-sensitive hydrogel/nanostructured lipid carrier(NLC) drug delivery platform. An ophthalmic antiinflammatory drug, baicalin(BN) was cho...The objective of this study was to develop a novel hybrid genipin-crosslinked dual-sensitive hydrogel/nanostructured lipid carrier(NLC) drug delivery platform. An ophthalmic antiinflammatory drug, baicalin(BN) was chosen as the model drug. BN –NLC was prepared using melt-emulsification combined with ultra-sonication technique. Additionally, a dual pH-and thermo-sensitive hydrogel composed of carboxymethyl chitosan(CMCS) and poloxamer 407(F127) was fabricated by a cross-linking reaction with a nontoxic crosslinker genipin(GP). GP-CMCS/F127 hydrogel was characterized by FTIR, NMR, XRD and SEM. The swelling studies showed GP-CMCS/F127 hydrogel was both pH-and thermo-sensitive. The results of in vitro release suggested BN –NLC gel can prolong the release of baicalin comparing with BN eye drops and BN –NLC. Ex vivo cornea permeation study was evaluated using Franz diffusion cells. The apparent permeability coefficient(Papp) of BN –NLC gel was much higher(4.46-fold) than that of BN eye drops. Through the determination of corneal hydration levels, BN –NLC gel was confirmed that had no significant irritation to cornea. Ex vivo precorneal retention experiments were carried out by a flow-through approach. The results indicated that the NLC-based hydrogel can prolong precorneal residence time. In conclusion, the hybrid NLCbased hydrogel has a promising potential for application in ocular drug delivery.展开更多
The nanostructure composite coating is obtained via plasma spraying of Al2O3-13 wt pct TiO2 powder. Brittle and hard lamella results from melted nanostructured powder. Ductile nanostructured matrix forms from unmelted...The nanostructure composite coating is obtained via plasma spraying of Al2O3-13 wt pct TiO2 powder. Brittle and hard lamella results from melted nanostructured powder. Ductile nanostructured matrix forms from unmelted nanostructured particles. Through the adjustment of constituent and nanostructure, hardness/strength and toughness/ductility are balanced and overall properties of the structure composite are achieved.展开更多
基金The financial supports by the Chinese Academy of Sciences(Nos.XDC04030300 and XDB0510303)CAS-HK Joint Laboratory of Nanomaterials and MechanicsShenyang National Laboratory for Materials Science are acknowledged.
文摘Rolling contact fatigue performance is among the most important issues for applications of bearing steels.In this work,a recently developed surface modification technique,surface mechanical rolling treatment,was applied on a rare-earth addition bearing steel.And rolling contact fatigue behavior of treated samples was compared with that of as-received counterparts at different contacting stresses.The results demonstrated that a 700μm-thick gradient nanostructured surface layer is produced on samples by surface mechanical rolling treatment.The grain size decreases while the microhardness increases gradually with decreasing depth,reaching~23 nm and~10.2 GPa,respectively,at the top surface.Consequently,the rolling contact fatigue property is significantly enhanced.The characteristic life of treated samples is~3.2 times that of untreated counterparts according to Weibull curves at 5.6 GPa.Analyses of fatigue mechanisms demonstrated that the gradient nanostructured surface layer might not only retard material degradation and microcrack formation,but also prolong the steady-state elastic response stage under rolling contact fatigue.
基金funding from the Australian Research Council(ARC Discovery Project,Nos.DP200101408 and DP230100183).
文摘1.Introduction The synthesis of bulk nanostructured multiphase(NM)mate-rials with extreme properties such as high hardness and strength is one of the most interesting research topics in materials science and engineering[1].At present,NM alloys can be produced by several synthesis methods,including sintering of nanocomposites[2,3],physical or chemical vapour deposition(PVD or CVD)[4],crystallization of metallic glasses[5],and severe plastic deforma-tion(SPD)[6-8].However,industry applications of bulk NM alloys produced by these methods are significantly restricted by their ge-ometrical and size limitations.Thus,the fabrication of large-scale NM alloys remains challenging.
基金supported by the National Natural Science Foundation of China(Nos.52371063 and 52072110)the Natural Science Foundation of Hebei Province(No.E2018202034)+1 种基金the Central Funds Guiding the Local Science and Technology Development of Hebei Province(No.236Z7610G)the Graduate Innovation Project of Hebei Province(No.CXZZBS2022035).
文摘High porosity and high brittleness are the main reasons that limit the long-term service life of the alumina-titanium oxide composite coating.Herein,a metastable nanostructured aluminatitanium oxide composite coating with high density and high properties was synthesized by plasma spraying of TiO_(2)-Al composite powder.The main phases of the metastable nanostructured alumina-titanium oxide wereγ-Al_(2)O_(3),TiO and AlTiO_(2).The coating,as prepared,contains various metastable microstructures,such as fine-grained,intra-/inter-granular,and"self-locking"microstructures.These metastable microstruc-tures are important for the improvement of hardness and toughness of the coating.Compared with other alumina-based composite coatings,the metastable nanostructured aluminatitanium oxide composite coating showed the most impressive overall performance.The reinforcing and toughening mechanism of the metastable alumina-titanium oxide composite coating included fine grain strengthening and self-toughening of the metastable microstructure.
基金supported by the National Nature Science Foundation of China(NSFC)(Grant No.11974033)Xuqiang Liu acknowledges support from the National Postdoctoral Foundation Project of China under Grant No.GZC20230215+2 种基金the National Nature Science Foundation of China under Grants No.12404001The XRD measurements at room and high temperatures were performed at the 4W2 HPStation of the Beijing Synchrotron Radiation Facility(BSRF)and beamline 15U1 of the Shanghai Synchrotron Radiation Facility(SSRF)In situ high-pressure,low-temperature XRD measurements were conducted at sector 16 ID-B,HPCAT of the Advanced Photon Source,and were supported by DOE-NNSA under Award No.DE-NA0001974.
文摘High-pressure β-Sn germanium may transform into diverse metastable allotropes with distinctive nanostructures and unique physical properties via multiple pathways under decompression.However,the mechanism and transition kinetics remain poorly understood.Here,we investigate the formation of metastable phases and nanostructures in germanium via controllable transition pathways of β-Sn Ge under rapid decompression at different rates.High-resolution transmission electron microscopy reveals three distinct metastable phases with the distinctive nanostructures:an almost perfect st12 Ge crystal,nanosized bc8/r8 structures with amorphous boundaries,and amorphous Ge with nanosized clusters (0.8–2.5 nm).Fast in situ x-ray diffraction and x-ray absorption measurements indicate that these nanostructured products form in certain pressure regions via distinct kinetic pathways and are strongly correlated with nucleation rates and electronic transitions mediated by compression rate,temperature,and stress.This work provides deep insight into the controllable synthesis of metastable materials with unique crystal symmetries and nanostructures for potential applications.
基金The authors thank the DFG(KI 2169/2-1)the European Union(EU-RIA NOMAD,101091669)for funding this work+1 种基金The Micro and Nanoanalytics Facility(MNaF),funded by the DFG(DFG INST 221/131-1)at the University of Siegen,and the Materials Science Faculty of the Isfahan University of Technology(IUT)were utilized for some of the work and analysis,respectively.
文摘This study introduces a nanostructured MgO coating fabricated via anodization in a non-aqueous electrolyte,offering a novel approach to addressing the challenges of corrosion resistance and biofunctionality.The surface was characterized before and after immersion testing using field emission scanning electron microscopy(FESEM),energy-dispersive X-ray spectroscopy(EDX),and X-ray diffraction(XRD).Electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization tests demonstrated a 2-fold reduction in the corrosion resistance compared to untreated magnesium.Biomineralization studies demonstrated the uniform formation of apatite with a Ca/P ratio of 1.35 on the nanostructured surface after 14 days in simulated body fluid(SBF),surpassing that of microstructured MgO.Hydrogen evolution decreased from 912±38μL cm^(-2)for untreated Mg to 615±32μL cm^(-2)for the Mg/MgO nanostructure and 545±29μL cm^(-2)for the Mg/Mg O/HA sample.These findings highlight the potential of nanostructured MgO coatings to advance Mg-based implants by providing enhanced corrosion protection,improved biomineralization,reduced hemolysis and increased cell viability,and reduced H_(2)generation.
基金supported by the National Key R&D Program of China(No.2022YFB4002502)the National Natural Science Foundation of China(No.22279057)。
文摘Solid oxide cells(SOCs)are attractive electrochemical energy conversion/storage technologies for electricity/green hydrogen production because of the high efficiencies,all-solid structure,and superb reversibility.Nevertheless,the widespread applications of SOCs are remarkably restricted by the inferior stability and high material costs induced by the high operational temperatures(600-800℃).Tremendous research efforts have been devoted to suppressing the operating temperatures of SOCs to decrease the overall costs and enhance the long-term durability.However,fuel electrodes as key components in SOCs suffer from insufficient(electro)catalytic activity and inferior impurity tolerance/redox resistance at reduced temperatures.Nanostructures and relevant nanomaterials exhibit great potential to boost the performance of fuel electrodes for low-temperature(LT)-SOCs due to the unique surface/interface properties,enlarged active sites,and strong interaction.Herein,an in-time review about advances in the design and fabrication of nanostructured fuel electrodes for LT-SOCs is presented by emphasizing the crucial role of nanostructure construction in boosting the performance of fuel electrodes and the relevant/distinct material design strategies.The main achievements,remaining challenges,and research trends about the development of nanostructured fuel electrodes in LT-SOCs are also presented,aiming to offer important insights for the future development of energy storage/conversion technologies.
基金supported by the Guangdong Industry Polytechnic University Student Research Project[grant numbers XSKYL202317]Guangdong Provincial Key Laboratory of Green Chemical Product Technology Open Project[grant numbers GC202117].
文摘Phenylethyl resorcinol(PR)demonstrates inhibitory effects on multiple targets in the melanin synthesis pathway,resulting in a strong whitening effect.However,challenges such as limited solubility in water and susceptibility to oxidation and discoloration restrict its practical application in the cosmetics industry.In order to enhance stability and performance characteristics,a whitening nanostructured lipid carrier(NLC)was synthesized through high-pressure homogenization.This method entailed the incorporation of solid lipids,a liquid lipid,and a compound emulsifier,with deionized water fulfilling the roles of solid phase,liquid phase,and water phase,respectively.The NLC's particle size,Zeta potential,stability,encapsulation efficiency,and other parameters were assessed using techniques such as particle sizer,stability analyzer,and HPLC.The results showed that the NLC for phenylethyl resorcinol prepared by using the optimal formula(7.50%solid lipids,3.00%ethylhexyl palmitate,and 2.00%Tween 80 and soybean lecithin)has an encapsulation efficiency of 87.11%,a particle size of 157.2±0.70 nm,a kinetic instability of less than 1.2,and a greatly improved stability,thereby successfully solving the problems of unstable storage and poor solubility of phenylethyl resorcinol.
文摘The Ni-based alloy composite coatings reinforced by nanostructured Al2O3-40%TiO2 multiphase ceramic particles were prepared on the surface of 7005 aluminum alloy by plasma spray technology. The microstructure and tribological properties of the composite coatings were researched. The results show that the composite coatings mainly consist of γ-Ni, α-Al2O3, γ-Al2O3 and rutile-TiO2 etc, and exhibit lower friction coefficients and wear losses than the Ni-based alloy coatings at different loads and speeds. The composite coating bears low contact stress at 3 N and its wear mechanism is micro-cutting wear. As loads increase to 6-12 N, the contact stress is higher than the elastic limit stress of worn surface, and the wear mechanisms change into multi-plastic deformation wear, micro-brittle fracture wear and abrasive wear. With the increase of speeds, the contact temperature of worn surface increases. The composite coating experiences multi-plastic deformation wear, fatigue wear and adhesive wear.
基金This study is supported by Jilin Forestry Group Co.
文摘The roots of 200 one-year-old Changbai Larch (Larix olgensis) seedlings were soaked for 6 hours at the TMS concentrations of 2000, 1000, 500, 250, 125, and 62 μL·L?1. Mean seedling height, root collar diameter, main root length and number of lateral roots were measured every 15 days during growing season from May 30 to Oct. 20. Experimental results showed that TMS treatments greatly promoted seedling growth and improved seedling quality. The treatment by 500 μL·L?1 TMS produced the best result, for which the mean height, root collar diameter, main root length, and the number of lateral roots of seedlings were increased by 42.5%, 30.7%, 14.0%, and 31.6%, respectively, compared to that of the control seedlings. As to seedling quality, grade-I seedling and grade-II seedlings were fifty-fifty, and no grade-III seedlings was found. The treatment by 500 μL·L?1 TMS resulted in the highest chlorophyll concentration. Keywords Changbai Larch - Larix olgensis - Seedling production - Nanostructured silicon dioxide CLC number S143.8 Document code B Foundation item: This study is supported by Jilin Forestry Group Co.Biography: LIN Baoshan (1955-), male, Associate professor at the college of forestry, Beihua University, Jilin City 132011, Jilin Province, P.R China.Responsible editor: Chai Ruihai.
基金National Natural Science Foundation of China(Grant No.81373364)The Subject clots Project Serving Pharmaceutical Industrial Innovation of Shanxi Province
文摘Artemisinin（ART） is a widely used active drug for malaria, including severe and cerebral malaria. However, its therapeutic efficacy is affected by its lower bioavailability. In the present study, nanostructured lipid carriers（NLCs） were proposed as carrier of ART to improve pharmacokinetic properties of the drug. ART-NLC was prepared by high-pressure homogenization based on orthogonal design. The particle size, zeta potential, encapsulation efficiency（EE） and percentage of drug loading（DL） of ART-NLC were（53.06±2.11） nm,（–28.7±3.59） m V, 73.9%±0.5% and 11.23%±0.37%, respectively. ART-NLC showed the sustained release characteristics and scarcely the hemolysis effect on human red blood cells. The pharmacokinetics of ART-NLC for rats after tail intravenous injection（i.v） or intraperitoneal injection（i.p） were investigated by liquid chromatography-tandem mass spectroscopy（LC-MS/MS）. And ART solution was designed as control preparation. For rats of i.v groups, the AUC0–∞（（707.45±145.65） ng·h/m L） of ART-NLC were significantly bigger than that of ART（（368.98±139.58） ng·h/m L）. The MRT（（3.38±0.46） h） of ART-NLC was longer than that of ART（（1.39±0.61） h）. And similar results were observed for rats of i.p groups. The AUC0–∞（（1233.06±235.57） ng·h/m L） and MRT（（4.97±0.69） h） of ART-NLC were both bigger than those of ART, which were（871.17±234.03） ng·h/m L） and（1.75±0.31） h）, respectively. Compared with ART, ART-NLC showed a significant increase in AUC0–∞（P〈0.05） and MRT（P〈0.001） for both i.p and tail i.v administrations.
基金National key Basic Research Program(Grant No.2013CB932501)National Natural Science Foundation of China(Grant No.81273454 and 81473156)+1 种基金Beijing National Science Foundation(Grant No.7132113)Doctoral Foundation of the Ministry of Education(Grant No.20130001110055)
文摘Surface modification may have important influences on the penetration behavior of nanoscale drug delivery system. In the present study, we mainly focused on whether cell targeting or cell penetration could affect penetration abilities of nanostructured lipid carriers（NLC）. Real--time penetration of folate--or cell penetrating peptide（CPP）-modified NLC was evaluated using a multicellular tumor spheroid（MTS） established by stacking culture method as an in vitro testing platform. The results suggested that CPP modification had a better penetration behavior both on penetration depth and intensity compared with folate-modified NLC at the early stage of penetration process.
基金the Natural Science Foundation of China (51831008 and 51471146)the National High Technology Research and Development Program of China (2012AA03A504)+2 种基金the National Science Foundation for Distinguished Young Scholars of China (50925522)the China Postdoctoral Science Foundation (2018M631762)the Youth Talent Projects of Colleges in Hebei Province (BJ2018056).
文摘Bearings are the most important component of nearly all mechanical equipment, as they guarantee the steady running of the equipment, which is especially important for high-end equipment such as highspeed trains and shield tunneling machines. Requirements regarding the quality of bearings are increasing with the rapid development in technology. A country’s bearings manufacturing level directly reflects the level of that country’s steel metallurgy and machinery manufacturing. The performance of the bearing steel is the critical factor that determines the quality of a bearing. The development of new bearing steel with higher performance is the ambition of material researchers and the expectation of the manufacturing industry. Many famous bearing manufacturing enterprises are competing to develop the new generation of bearing steel. Nanostructured bainitic bearing steel (NBBS), which is a newly developed bearing steel, not only possesses high strength and toughness, but also exhibits excellent wear resistance and rolling contact fatigue (RCF) resistance. In recent years, relevant achievements in NBBS in China have led to significant progress in this field. NBBS was first used in China to manufacture large bearings for wind turbines and heavy-duty bearings, with excellent performance. As a result, NBBS and its corresponding heat-treatment process have been included in the national and industry standards for the first time. The bearing industry considers the exploitation of NBBS to be epoch-making, and has termed this kind of bearing as the second generation of bainitic bearing. In this paper, the development of NBBS is reviewed in detail, including its advantages and disadvantages. Further research directions for NBBS are also proposed.
文摘The microstructure and wear performance of M203-13% TiO2 coatings prepared by plasma spraying of agglom- erated nanoparticle powders were investigated. SEM analysis showed that the as-sprayed Al2O3-TiO2 coatings comprise of two kinds of typical region： fully melted region and unmelted/partially melted nanostructured region, which is different than the conventional coating with lamellar structure. It is shown that the microhardness of the nanostructured coatings was about 15%-30% higher than that of the conventional coating and the wear resistance is significantly improved, especially under a high wear load. The nanostructured coating sprayed at a lower power shows a lower wear resistance than the coatings produced at a higher power, because of the presence of pores and microstructural defects which are detrimental to the fracture toughness of the coatings.
基金supported by the National Nature Science Foundation of China(Nos.51272025,50872011,and 50672006)the Major State Basic Research and Development Program of China(No.2007CB613608)
文摘Nanostructured Fe-doped titanium dioxide was synthesized from titanium containing electric furnace molten slag （TCEFMS） by using an alkali fusion, followed by a hydrolyzation-acidolysis-cMcination route. The effects of Mkali/slag mass ratio, calcinating temperature, calcinating time, and water/slag mass ratio on the extraction efficiency and purity of products were systematically studied in this paper. It is indicated that the best extraction efficiency of nanostructured Fe- doped titanium dioxide is 99.35%, when the molten slag is calcinated at 700℃ for 1 h with the mass ratio of alkali/molten slag of 1.5：1. The influence of alkali/slag mass ratio on the photocatalytic activity of final products was evaluated by the photodegradation of methyl blue under visible light irradiation. A maximum photodegradation efficiency of 88.12% over 30 min was achieved under the optimum conditions.
基金supported by the National Natural Science Foundation of China (No. 20907022,21003094)the Doctoral Program of Higher Education of China(No. 200800551003,20100032120066)the Special Projects of Environmental Protection (No. 2009ZX07526,2009ZX07208,200909101,2009GJA10021)
文摘Cerium-doped SiO2/TiO2 nanostructured fibers were fabricated by electrospinning technology. The prepared fibers were characterized by thermogravimetric analysis （TGA）, scanning electron microscopy （SEM）, X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FT-IR）. Using the fibers as catalysts, photoeatalytic degradation of Methylene Blue （MB） aqueous solution was carded out under simulated sunlight. The 0.2% Ce doping proved to be the optimal concentration for the doping of TiO2/SiO2, compared to other Ce-doped molar concentrations. The 0.2% Ce-doped SiOdTiO2 fibers exhibited higher photocatalytic activity than industrial Degussa P25 and the samples doped with only Ce or SIO2. The reasons for improving the photocatalytic activity were also discussed. Several operational parameters were studied, which showed that the photocatalytic efficiency of MB was influenced by parameters such as the initial dye concentration, the initial pH, inorganic anions, and so on. In addition, the influences of an electron acceptor and a radical scavenger suggested that OH was the dominant photooxidant during the photocatalytic process. The reuse evaluation of the fibers indicated that their photocatalytic activity had good stability.
基金This work was supported by Taishan Scholars Project Special Funds(tsqn201812083)Natural Science Foundation of Shandong Province(ZR2019YQ20,2019JMRH0410,ZR2019BB001)the National Natural Science Foundation of China(51972147,51902132,52022037).
文摘Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.
基金supported by Beijing Natural Science Foundation of China(No.7122176)National Natural Science Foundation of China(No.81102821)National Key New Drugs Innovation Foundation(Nos.2014ZX09J14106-01A and CWS11J165)
文摘The objective of this study was to prepare nanostructured lipid carrier(NLC)-based topical gel of Ganoderma Triterpenoids(GTs) and evaluate their effects on frostbite treatment. GT-NLCs was prepared by the high pressure homogenization method and then characterized by morphology and analyses of particle size, zeta potential, entrapment efficiency(EE), and drug loading(DL). The NLCs was suitably gelled for skin permeation studies in vitro and pharmacodynamic evaluation in vivo, compared with the GT emulgel. The GT-NLC remained within the colloidal range and was uniformly dispersed after suitably gelled by carbopol preparation. Transmission electron microscopy(TEM) study showed GT-NLCs was spherical in shape. The EE(%) and DL(%) could reach up to(81.84 ± 0.60)% and(2.13 ± 0.12)%, respectively. The result of X-ray diffractograms(XRD) showed that GTs were in an amorphous state in the NLC-gel. In vitro permeation studies through rat skin indicated that the amount of GTs permeated through skin of GT-NLCs after 24 h was higher than that of GT emulsion, and GT-NLCs increased the accumulative amounts of GTs in epidermis 7.76 times greater than GT emulsion. GT-NLC-gel was found to possess superior therapeutic effect for frostbite, compared with the GT emulgel. The NLC based topical gel of GTs could improve-their therapeutic effect for frostbite.
基金supported by NIH R01 DE14190 and R21 DE22625 (HX)National Science Foundation of China 31100695 and 31328008 (LZ), 81401794 (PW)Maryland Stem Cell Research Fund and University of Maryland School of Dentistry
文摘Tissue engineering is promising to meet the increasing need for bone regeneration. Nanostructured calcium phosphate （CAP） biomaterials/scaffolds are of special interest as they share chemical/crystallographic similarities to inorganic components of bone. Three applications of nano-CaP are discussed in this review： nanostructured calcium phosphate cement （CPC）; nano-CaP composites; and nano-CaP coatings. The interactions between stem cells and nano-CaP are highlighted, including cell attachment, orientation/ morphology, differentiation and in vivo bone regeneration. Several trends can be seen： （i） nano-CaP biomaterials support stem cell attachment/proliferation and induce osteogenic differentiation, in some cases even without osteogenic supplements; （ii） the influence of nano-CaP surface patterns on cell alignment is not prominent due to non-uniform distribution of nano-crystals; （iii） nano-CaP can achieve better bone regeneration than conventional CaP biomaterials; （iv） combining stem cells with nano-CaP accelerates bone regeneration, the effect of which can be further enhanced by growth factors; and （v） cell microencapsulation in nano-CaP scaffolds is promising for bone tissue engineering. These understandings would help researchers to further uncover the underlying mechanisms and interactions in nano-CaP stem cell constructs in vitro and in vivo, tailor nano-CaP composite construct design and stem cell type selection to enhance cell function and bone regeneration, and translate laboratory findings to clinical treatments.
基金National Natural Science Foundation of China (projects 81473163 and 81773670) for supporting the research
文摘The objective of this study was to develop a novel hybrid genipin-crosslinked dual-sensitive hydrogel/nanostructured lipid carrier(NLC) drug delivery platform. An ophthalmic antiinflammatory drug, baicalin(BN) was chosen as the model drug. BN –NLC was prepared using melt-emulsification combined with ultra-sonication technique. Additionally, a dual pH-and thermo-sensitive hydrogel composed of carboxymethyl chitosan(CMCS) and poloxamer 407(F127) was fabricated by a cross-linking reaction with a nontoxic crosslinker genipin(GP). GP-CMCS/F127 hydrogel was characterized by FTIR, NMR, XRD and SEM. The swelling studies showed GP-CMCS/F127 hydrogel was both pH-and thermo-sensitive. The results of in vitro release suggested BN –NLC gel can prolong the release of baicalin comparing with BN eye drops and BN –NLC. Ex vivo cornea permeation study was evaluated using Franz diffusion cells. The apparent permeability coefficient(Papp) of BN –NLC gel was much higher(4.46-fold) than that of BN eye drops. Through the determination of corneal hydration levels, BN –NLC gel was confirmed that had no significant irritation to cornea. Ex vivo precorneal retention experiments were carried out by a flow-through approach. The results indicated that the NLC-based hydrogel can prolong precorneal residence time. In conclusion, the hybrid NLCbased hydrogel has a promising potential for application in ocular drug delivery.
文摘The nanostructure composite coating is obtained via plasma spraying of Al2O3-13 wt pct TiO2 powder. Brittle and hard lamella results from melted nanostructured powder. Ductile nanostructured matrix forms from unmelted nanostructured particles. Through the adjustment of constituent and nanostructure, hardness/strength and toughness/ductility are balanced and overall properties of the structure composite are achieved.
