Modulating the activation state and degree of macrophages still remains as a challenge for the topographical design of Ti-based implants.In this work,micro/nano-structured coatings were prepared on Ti substrates by mi...Modulating the activation state and degree of macrophages still remains as a challenge for the topographical design of Ti-based implants.In this work,micro/nano-structured coatings were prepared on Ti substrates by micro-arc oxidation(MAO)and subsequent hydrothermal(HT)treatment.By varying the HT conditions,plate-like nano-structures with an average length of 80,440 or 780 nm were obtained on MAO-prepared micro-topographical surfaces.Depending on the dimensional features of nano-plates,the specimens were noted as Micro,Micro/Nano-180,Micro/Nano-440 and Micro/Nano-780,respectively.The in vitro results showed that the activation state and degree of macrophages could be effectively modulated by the micro/nano-structured surfaces with various dimensional features.Compared to the Micro surface,the Micro/Nano-180 surface activated both M1 and M2 phenotype in macrophages,while the Micro/Nano-440 and Micro/Nano-780 surfaces polarized macrophages to their M1 phenotype.The activation degree of M1 macrophages followed the trend:Micro<Micro/Nano-180<Micro/Nano-440<Micro/Nano-780.However,the osteogenic potential of the activated macrophages in response to various surfaces were in the order:Micro≈Micro/Nano-780<Micro/Nano-180<Micro/Nano-440.Together,the findings presented in this work indicate that engineering nano-structures with controllable dimensional features is a promising strategy to modulate macrophage activation state and degree.In addition,it is essential to determine the appropriate activation degree of M1 macrophages for enhanced osteogenesis.展开更多
Changes in trace substances in human metabolites, which are related to disease processes and health status, can serve as chemical markers for disease diagnosis and symptom monitoring. Real-time online detection is an ...Changes in trace substances in human metabolites, which are related to disease processes and health status, can serve as chemical markers for disease diagnosis and symptom monitoring. Real-time online detection is an inevitable trend for the future of health monitoring, and the construction of chips for detection faces major challenges. The response of sensors often fails to meet the requirements for chipbased detection of trace substances due to the low efficiency of interfacial heterogeneous reactions, necessitating a rational design approach for micro-and nano-structures to improve sensor performance with respect to sensitivity and detection limits. This review focuses on the influence of micro-and nanostructures that used in chip on sensing. Firstly, this review categorizes sensors into chemiresistors, electrochemical sensors, fluorescence sensors, and surface enhanced Raman scattering(SERS) sensors based on their sensing principle, which have significant applications in disease diagnosis. Subsequently, commencing from the application requirements in the field of sensing, this review focuses on the different structures of nanoparticle(NP) assemblies, including wire, layered, core-shell, hollow, concave and deformable structures. These structures change in the size, shape, and morphology of conventional structures to achieve characteristics such as ordered alignment, high specific surface area, space limitation,vertical diffusion, and swaying behavior with fluid, thereby addressing issues such as poor signal transmission efficiency, inadequate adsorption and capture capacity, and slow mass transfer speed during sensing. Finally, the design direction of micro-and nano-structures, and possible obstacles and solutions to promote chip-based detection have been discussed. It is hope that this article will inspire the exploration of interface micro-and nano-structures modulated sensing methods.展开更多
Graphite electrodes were used for the direct current （DC） arc discharge in water. And high-resolution transmission electron microscopy （HRTEM） was used to investigate the products. Based on the experimental phenom...Graphite electrodes were used for the direct current （DC） arc discharge in water. And high-resolution transmission electron microscopy （HRTEM） was used to investigate the products. Based on the experimental phenomena and nano-structure products, arc plasma characteristics in water were analyzed theoretically. Two growth regions and relevant growth modes were proposed to interpret the formation mechanisms of nano-structures by arc discharge in water. Furthermore, liquid nitrogen and cross magnetic field was applied to change the arcing state respectively, and new carbon nano-structures were obtained. Their formation mechanisms were also analyzed correspondingly.展开更多
The investigation on the oxidation behaviour of Si1-xGex alloys （x=0.05, 0.15, and 0.25） is carried out. It is found for the first time that on the oxide film a germanium nano-cap with a thickness of 1.8-2.8nm and a...The investigation on the oxidation behaviour of Si1-xGex alloys （x=0.05, 0.15, and 0.25） is carried out. It is found for the first time that on the oxide film a germanium nano-cap with a thickness of 1.8-2.8nm and a few Ge nanoparticles with diameters ranging from 5.5 nm to 10 nm are formed by the low-temperatu.re laser-assisted dry oxidation of Si1-xGex substrate. A new scanning method on the decline cross-section of the multiple-layer sample is adopted to measure the layer thickness and the composition. Some new peaks in photoluminescence （PL） spectra are discovered, which could be related to the nano-cap and the nano-particles of germanium. A suitable model and several new calculating formulae with the unrestricted Hartree-Fock-Roothaan （UHFR） method and quantum confinement analysis are proposed to interpret the PL spectra and the nano-structure mechanism in the oxide.展开更多
We report the synthesis and electrochemical sodium storage of cobalt disulfide （COS2） with various micro/nano-structures. CoS2 with microscale sizes are either assembled by nanoparticles （P-CoS2） via a facile solv...We report the synthesis and electrochemical sodium storage of cobalt disulfide （COS2） with various micro/nano-structures. CoS2 with microscale sizes are either assembled by nanoparticles （P-CoS2） via a facile solvothermal route or nano- octahedrons constructed solid （O-COS2） and hollow microstructures （H-CoS2） fabricated by hydrothermal methods. Among three morphologies, H-CoS2 exhibits the largest discharge capacities and best rate performance as anode of sodium-ion batteries （SIBs）. Furthermore, H-CoS2 delivers a capacity of 690 mA.h.g 1 at 1 A·g 1 after 100 cycles in a potential range of 0.1-3.0 V, and N240 mA.h.g-1 over 800 cycles in the potential window of 1.0-3.0 V. This cycling difference mainly lies in the two discharge plateaus observed in 0.1-3.0 V and one discharge plateau in 1.0-3.0 V. To interpret the reactions, X-ray diffraction （XRD） and transmission electron microscopy （TEM） are applied. The results show that at the first plateau around 1.4 V, the insertion reaction （COS2 ＋ xNa＊ ＋ xe NaxCoS2） Occurs; while at the second plateau around 0.6 V, the conversion reaction （NaxCoS2 ＋ （4 - x） Na＋ ＋ （4 - x）e -~ Co ＋ 2Na2S） takes place. This provides insights for electrochemical sodium storage of CoS2 as the anode of SIBs.展开更多
Electrohydrodynamicjet （E-Jet） is an approach to the fabrication of micro/nano-structures by the use of electrical forces. In this process, the liquid is subjected to electrical and mechanical forces to form a liqui...Electrohydrodynamicjet （E-Jet） is an approach to the fabrication of micro/nano-structures by the use of electrical forces. In this process, the liquid is subjected to electrical and mechanical forces to form a liquid jet, which is further disintegrated into droplets. The major advantage of the E-Jet technique is that the sizes of the jet formed can be at the nanoscale far smaller than the nozzle size, which can realize high printing resolution with less risk of nozzle blockage. The E-Jet technique, which mainly includes E-Jet deposition and E-Jet printing, has a wide range of applications in the fabrication ofmicro/nano-structures for micro/nano-electromechanical system devices. This tech- nique is also considered a micro/nano-fabrication method with a great potential for commercial use. This study mainly reviews the E-Jet deposition/printing fundamentals, fabrication process, and applications.展开更多
Hydrogels, composed mainly of water trapped in three dimensional cross-linked polymer networks, have been widely utilized to construct underwater superoleophobic surfaces. However, the swelling nature and instability ...Hydrogels, composed mainly of water trapped in three dimensional cross-linked polymer networks, have been widely utilized to construct underwater superoleophobic surfaces. However, the swelling nature and instability of hydrogels under complex marine environment will weaken their underwater superoleophobicity. Herein, we synthesize structured poly （2-hydroxyethylmethacrylate） （PHEMA） hydrogels by using sandpaper as templates. The robust non-swelling of PHEMA hydrogel ensures that micro/nano-structures on the surface of PHEMA hydrogels can be well maintained. Moreover, when roughness Ra of about 3-4 bun, the surface has superior oil-repellency. Additionally, even after immersing in seawater for one-month, their breaking strength and toughness can be well kept. The non-swellable hydrogels with long-term stable under seawater superoleophobicity will promote the development of robust superoleophobic materials in marine antifouling coatings, biomedical devices and oil/water separation.展开更多
A novel oxide-dispersion-strengthened(ODS)die steel was fabricated by mechanical alloying and hot consolidation.Annealing and quench-tempering treatments both obtained an ultra-fine grain structure(mean size:310-330 n...A novel oxide-dispersion-strengthened(ODS)die steel was fabricated by mechanical alloying and hot consolidation.Annealing and quench-tempering treatments both obtained an ultra-fine grain structure(mean size:310-330 nm)with an ultra-high density of ultra-fine Y-Al-O nano-oxides(number density:~(1-1.5)×10^(23)m^(−3),mean size:5.1-7.2 nm).Prolonged thermal exposure further induced the new,highly dense precipitation of ultra-fine Y-Zr-O nano-oxides.Both nano-oxides tended to be wrapped up with a B2-NiAl nano-shells.Although the quench-tempered sample showed much higher room-temperature strength(yield strength=1393±40 MPa and ultimate tensile strength=1774±11 MPa)and slightly lower elongation(elongation=13.6%±0.6%)than the annealed sample(YS=988±7 MPa,UTS=1490±12 MPa,and EL=15.2%±1.1%),both samples exhibited better strength-ductility synergy at room temperature and much higher thermal stabilities at high temperatures(600-700℃)than all those conventional hot-work die steels,which makes the new ODS steel highly promising for advanced hot-work mold and die applications at high temperatures above 600℃.展开更多
In the present work, osteoblast behavior on a hierarchical micro-/nano-structured titanium surface was investigated. A hi- erarchical hybrid micro-/nano-structured titanium surface topography was produced via Electrol...In the present work, osteoblast behavior on a hierarchical micro-/nano-structured titanium surface was investigated. A hi- erarchical hybrid micro-/nano-structured titanium surface topography was produced via Electrolytic Etching （EE）. MG-63 cells were cultured on disks for 2 h to 7 days. The osteoblast response to the hierarchical hybrid micro-/nano-structured titanium surface was evaluated through the osteoblast cell morphology, attachment and proliferation. For comparison, MG-63 cells were also cultured on Sandblasted and Acid-etched （SEA） as well as Machined （M） surfaces respectively. The results show signifi- cant differences in the adhesion rates and proliferation levels of MG-63 cells on EE, SLA, and M surfaces. Both adhesion rate and proliferation level on EE surface are higher than those on SLA and M surfaces. Therefore, we may expect that, comparing with SLA and M surfaces, bone growth on EE surface could be accelerated and bone formation could be promoted at an early stage, which could be applied in the clinical practices for immediate and early-stage loadings.展开更多
The nano-structural Al-doped ZnO thin films of different morphologies deposited on glass substrate were successfully fabricated at substrate temperature of 350 ℃ by an inexpensive spray pyrolysis method. The structur...The nano-structural Al-doped ZnO thin films of different morphologies deposited on glass substrate were successfully fabricated at substrate temperature of 350 ℃ by an inexpensive spray pyrolysis method. The structural, electrical, optical and photoluminescence properties were investigated. X-ray diffraction study revealed the crystalline wurtzite （hexagonal） structure of the films with nano-grains. Scanning electron microscopy （SEM） micrographs indicated the formation of a large variety of nano-structures during film growth. The spectral absorption of the films occurred at the absorption edge of -410 nm. In the present study, the optical band gap energy 3.28 eV of ZnO decreased gradually to 3.05 eV for 4 mol% of AI doping. The deep level activation energy decreased and carrier concentrations increased substantially with increasing doping. Exciting with the energy 3.543 eV （A=350 nm）, a narrow and a broad characteristic photoluminescence peaks that correspond to the near band edge （NBE） and deep level emissions （DLE）, respectively emerged.展开更多
To reduce the problems of poor solubility,high in vivo dosage requirement,and weak targeting ability of paclitaxel(PTX),a hyaluronic acid-octadecylamine(HA-ODA)-modified nano-structured lipid carrier(HA-NLC)was constr...To reduce the problems of poor solubility,high in vivo dosage requirement,and weak targeting ability of paclitaxel(PTX),a hyaluronic acid-octadecylamine(HA-ODA)-modified nano-structured lipid carrier(HA-NLC)was constructed.HA-ODA conjugates were synthesized by an amide reaction between HA and ODA.The hydrophobic chain of HA-ODA can be embedded in the lipid core of the NLC to obtain HA-NLC.The HA-NLC displayed strong internalization in cluster determinant 44(CD44)highly expressed MCF-7 cells,and endocytosis mediated by the CD44 receptor was involved.The HA-NLC had an encapsulation efficiency of PTX of 72.0%.The cytotoxicity of the PTXloaded nanoparticle HA-NLC/PTX in MCF-7 cells was much stronger than that of the commercial preparation Taxol.In vivo,the HA-NLC exhibited strong tumor targeting ability.The distribution of the NLCs to the liver and spleen was reduced after HA modification,while more nanoparticles were aggregated to the tumor site.Our results suggest that HA-NLC has excellent properties as a nano drug carrier and potential for in vivo targeting.展开更多
Nano-structured SiO2 thin films were prepared on the surface of carbon steel for the first time by LPD. The compositions of the films were analyzed by XPS, and the surface morphology of the thin films were observed b...Nano-structured SiO2 thin films were prepared on the surface of carbon steel for the first time by LPD. The compositions of the films were analyzed by XPS, and the surface morphology of the thin films were observed by AFM. The thin films were constituted by compact particles of SiO2, and there was no Fe in the films. In the process of film forming, the SiO2 colloid particles were deposited or absorbed directly onto the surface of carbon steel substrates that were activated by acid solution containing inhibitor, and corrosion of the substrates was avoided. The nano-structured SiO2 thin films that were prepared had excellent protective efficiency to the carbon steel.展开更多
A bulk nanostructured twinning-induced plasticity （TWIP） steel with high ductility and high strength was fabricated by cryogenic asymmetry-rolling （cryo-ASR） and subsequent recovery treatment. It was found that th...A bulk nanostructured twinning-induced plasticity （TWIP） steel with high ductility and high strength was fabricated by cryogenic asymmetry-rolling （cryo-ASR） and subsequent recovery treatment. It was found that the cryo-ASRed TWIP steels exhibit simultaneous improvements in the ductility, strength and work hardening. Typical microstructures of the cryo-ASR TWIP steel were characterized by shear bands and intensive mechanical nano-sized twins induced by cryogenic deformation. These mechanical nano-scale twins remain thermally stable during the subsequent recovery treatment. It is believed that the ductility enhancement and high work-hardening ability for the cryo-ASR TWIP steels should be mainly attributed to the high-densitv pre-existing nano-scale twins.展开更多
There exist strong interests of developing nano-grained steels because of the outstanding properties including high strength/weight ratio, wear resistance, excellent toughness, and favorable cellular activity. This ar...There exist strong interests of developing nano-grained steels because of the outstanding properties including high strength/weight ratio, wear resistance, excellent toughness, and favorable cellular activity. This article reviews the main fabrication process and microstructural control of nano-structured steels over the last decades. Severe plastic deformation is considered as an effective route of obtaining the nano-grained microstructures. The process of cold-rolling and annealing of martensitic steel is a viable method to obtain bulk nano-structured low carbon steel, while the final thickness of the cold-rolling plate is limited. According to the theoretical results of the thermal simulation studies, a novel alloy design combined with the rapid transformation and rolling process is proposed to successfully fabricate nano-grained high strength bulk steel. The refinement mechanisms are expected to be taking advantage of increase in the transformation nucleation sites and inhibiting the grain coarsening. Moreover, corresponding mechanical properties are summarized.展开更多
Silver nano-particles with average diameter of about 60 nm were compacted in a high-strength mold under different pressures at 523 K to produce nano-structured Ag solid materials. The structure and characteristic of t...Silver nano-particles with average diameter of about 60 nm were compacted in a high-strength mold under different pressures at 523 K to produce nano-structured Ag solid materials. The structure and characteristic of the nano-structured Ag solid materials (NSS-Ag) were studied using X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman spectrometer. The NSS-Ag could be used as highly efficient surface-enhanced Raman scattering (SERS) active substrates. The common probe molecules Rhodamine 6G (R6G, 1×10-10 mol/L) were used to test the SERS activity on these substrates at very low concentrations. It is found that the SERS enhancement ability is dependent on the density of NSS-Ag. When the relative density of NSS-Ag is 83.87%, the materials reveal great SERS signal.展开更多
The initial field electron emission degradation behaviour of original nano-structured sp^2-bonded amorphous carbon films has been observed, which can be attributed to the increase of the work function of the film in t...The initial field electron emission degradation behaviour of original nano-structured sp^2-bonded amorphous carbon films has been observed, which can be attributed to the increase of the work function of the film in the field emission process analysed using a Fowler-Nordheim plot. The possible reason for the change of work function is suggested to be the desorption of hydrogen from the original hydrogen termination film surface due to field emission current-induced local heating. For the explanation of the emission degradation behaviour of the nano-structured sp2-bonded amorphous carbon film, a cluster model with a series of graphite （0001） basal surfaces has been presented, and the theoretical calculations have been performed to investigate work functions of graphite （0001） surfaces with different hydrogen atom and ion chemisorption sites by using first principles method based on density functional theory-local density approximation.展开更多
Cu-Zn-Al alloy of one dimensional nano-structure was prepared and thestructure of obtained nano-material was characterized by transmission electron microscope (TEM). Itwas shown that there are non-linear oscillations ...Cu-Zn-Al alloy of one dimensional nano-structure was prepared and thestructure of obtained nano-material was characterized by transmission electron microscope (TEM). Itwas shown that there are non-linear oscillations on the surface of Cu-Zn-Al alloy and theconsanguineous connection exists between non-linear oscillation and the growth process of onedimensional nano-structure. The diameter of one dimensional nano-structure is about 40 nm, and theratio of length to diameter is over 40. Finally, the growth mechanism of one dimensionalnano-structure was also studied.展开更多
First-principles energetics analyses were performed to investigate the nucleation of(Y-Si-O)nano-clusters(NCs)in nanostructured ferritic alloys(NFAs).It was predicted that the nucleation of(Y-Si-O)NCs follows the same...First-principles energetics analyses were performed to investigate the nucleation of(Y-Si-O)nano-clusters(NCs)in nanostructured ferritic alloys(NFAs).It was predicted that the nucleation of(Y-Si-O)NCs follows the same general pathway as previously found for(Y-Ti/Al/Zr-O)NCs in NFAs:they all tend to begin with the(O-O)pairs and grow to(O-Y)-cores and further to larger NCs by attracting Y and other solute elements nearby.Nucleation of a hexa-atomic-[2Y-Si-3O]-cluster can reduce the total energy by 4.71 eV.Among various microalloying-induced NCs,the nucleation preference ordering was predicted as(Y-Zr-O)>(Y-Ti-O)>(Y-Al-O)>(Y-Si-O).The number densities and chemical compositions of NCs in multi-microalloyed NFAs would largely depend on the number availability of(O,Y)-cores,as well as the relative abundance and atomic diffusivities of microalloying solute elements nearby.展开更多
Cobalt supported on carbon nanotubes （CNTs）-covered alumina has been recently developed and successfully utilized as a catalyst in Fischer-Tropsch synthesis （FTS）. Problems associated with shaping of Co/CNTs into ...Cobalt supported on carbon nanotubes （CNTs）-covered alumina has been recently developed and successfully utilized as a catalyst in Fischer-Tropsch synthesis （FTS）. Problems associated with shaping of Co/CNTs into extrudates or pellets as well as catalyst attrition rendered these materials unfavorable for industrial applications. In this investigation regular γ- and nano-structured （N-S） alumina as well as CNTs-covered regular γ- and N-S-alumina supports were impregnated by cobalt nitrate solution to make new cobalt-based catalysts which were also promoted by Ru. The catalysts were characterized and tested in a micro reactor to evaluate their applicability in FTS. γ-Al2O3 was prepared by calcination of bohemite and N-S-Al2O3 was prepared by sol-gel method using aluminum chloride as starting material. Catalyst evaluations indicated that N-S-Al2O3 was superior to regular γ-Al2O3 and that CNTs-covered alumina supports were favored over non-covered ones in terms of activity and heavy hydrocarbon selectivity. These were justified by porosimetric characteristics of the catalysts and existence of CNTs points of view. CNTs-covered catalysts also showed higher wax selectivity and better resistance to deactivation. Furthermore, TPR analysis indicated that the cobalt aluminate phase, which is responsible for the permanent deactivation of alumina supported Co-based catalysts, did not form on alumina supported Co-based catalysts covered with CNTs due to weaker interactions between cobalt and alumina.展开更多
It was reported that due to the non-linear electrical phenomena,the super-saturated arsenic in silicon single crystalline precipitates during post processing at low temperatures to form different structures.The struct...It was reported that due to the non-linear electrical phenomena,the super-saturated arsenic in silicon single crystalline precipitates during post processing at low temperatures to form different structures.The structure with spatial period of 1.7 to 2.3 nm was observed firstly by TEM on the sample.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51771233,52071346 and 51604104)China Postdoctoral Science Foundation(Grant No.2018M633164)+1 种基金Innovation-oriented Advanced Technology and Industrial Technology Program Project of Hunan Province(Grant No.2020SK2017)Guangdong Basic and Applied Basic Research Foundation(Grant No.2019A1515110736)。
文摘Modulating the activation state and degree of macrophages still remains as a challenge for the topographical design of Ti-based implants.In this work,micro/nano-structured coatings were prepared on Ti substrates by micro-arc oxidation(MAO)and subsequent hydrothermal(HT)treatment.By varying the HT conditions,plate-like nano-structures with an average length of 80,440 or 780 nm were obtained on MAO-prepared micro-topographical surfaces.Depending on the dimensional features of nano-plates,the specimens were noted as Micro,Micro/Nano-180,Micro/Nano-440 and Micro/Nano-780,respectively.The in vitro results showed that the activation state and degree of macrophages could be effectively modulated by the micro/nano-structured surfaces with various dimensional features.Compared to the Micro surface,the Micro/Nano-180 surface activated both M1 and M2 phenotype in macrophages,while the Micro/Nano-440 and Micro/Nano-780 surfaces polarized macrophages to their M1 phenotype.The activation degree of M1 macrophages followed the trend:Micro<Micro/Nano-180<Micro/Nano-440<Micro/Nano-780.However,the osteogenic potential of the activated macrophages in response to various surfaces were in the order:Micro≈Micro/Nano-780<Micro/Nano-180<Micro/Nano-440.Together,the findings presented in this work indicate that engineering nano-structures with controllable dimensional features is a promising strategy to modulate macrophage activation state and degree.In addition,it is essential to determine the appropriate activation degree of M1 macrophages for enhanced osteogenesis.
基金financially supported by the National Natural Science Foundation of China (No.21925405)。
文摘Changes in trace substances in human metabolites, which are related to disease processes and health status, can serve as chemical markers for disease diagnosis and symptom monitoring. Real-time online detection is an inevitable trend for the future of health monitoring, and the construction of chips for detection faces major challenges. The response of sensors often fails to meet the requirements for chipbased detection of trace substances due to the low efficiency of interfacial heterogeneous reactions, necessitating a rational design approach for micro-and nano-structures to improve sensor performance with respect to sensitivity and detection limits. This review focuses on the influence of micro-and nanostructures that used in chip on sensing. Firstly, this review categorizes sensors into chemiresistors, electrochemical sensors, fluorescence sensors, and surface enhanced Raman scattering(SERS) sensors based on their sensing principle, which have significant applications in disease diagnosis. Subsequently, commencing from the application requirements in the field of sensing, this review focuses on the different structures of nanoparticle(NP) assemblies, including wire, layered, core-shell, hollow, concave and deformable structures. These structures change in the size, shape, and morphology of conventional structures to achieve characteristics such as ordered alignment, high specific surface area, space limitation,vertical diffusion, and swaying behavior with fluid, thereby addressing issues such as poor signal transmission efficiency, inadequate adsorption and capture capacity, and slow mass transfer speed during sensing. Finally, the design direction of micro-and nano-structures, and possible obstacles and solutions to promote chip-based detection have been discussed. It is hope that this article will inspire the exploration of interface micro-and nano-structures modulated sensing methods.
基金National Natural Science Foundation of China (No.50377030)
文摘Graphite electrodes were used for the direct current （DC） arc discharge in water. And high-resolution transmission electron microscopy （HRTEM） was used to investigate the products. Based on the experimental phenomena and nano-structure products, arc plasma characteristics in water were analyzed theoretically. Two growth regions and relevant growth modes were proposed to interpret the formation mechanisms of nano-structures by arc discharge in water. Furthermore, liquid nitrogen and cross magnetic field was applied to change the arcing state respectively, and new carbon nano-structures were obtained. Their formation mechanisms were also analyzed correspondingly.
基金Project supported by the Natural Science Foundation of Guizhou Province, China （Grant No 3067（2004））.
文摘The investigation on the oxidation behaviour of Si1-xGex alloys （x=0.05, 0.15, and 0.25） is carried out. It is found for the first time that on the oxide film a germanium nano-cap with a thickness of 1.8-2.8nm and a few Ge nanoparticles with diameters ranging from 5.5 nm to 10 nm are formed by the low-temperatu.re laser-assisted dry oxidation of Si1-xGex substrate. A new scanning method on the decline cross-section of the multiple-layer sample is adopted to measure the layer thickness and the composition. Some new peaks in photoluminescence （PL） spectra are discovered, which could be related to the nano-cap and the nano-particles of germanium. A suitable model and several new calculating formulae with the unrestricted Hartree-Fock-Roothaan （UHFR） method and quantum confinement analysis are proposed to interpret the PL spectra and the nano-structure mechanism in the oxide.
基金This work was supported by the National Natural Science Foundation of China （No. 51231003） and MOE （Nos. B12015 and IRT13R30）.
文摘We report the synthesis and electrochemical sodium storage of cobalt disulfide （COS2） with various micro/nano-structures. CoS2 with microscale sizes are either assembled by nanoparticles （P-CoS2） via a facile solvothermal route or nano- octahedrons constructed solid （O-COS2） and hollow microstructures （H-CoS2） fabricated by hydrothermal methods. Among three morphologies, H-CoS2 exhibits the largest discharge capacities and best rate performance as anode of sodium-ion batteries （SIBs）. Furthermore, H-CoS2 delivers a capacity of 690 mA.h.g 1 at 1 A·g 1 after 100 cycles in a potential range of 0.1-3.0 V, and N240 mA.h.g-1 over 800 cycles in the potential window of 1.0-3.0 V. This cycling difference mainly lies in the two discharge plateaus observed in 0.1-3.0 V and one discharge plateau in 1.0-3.0 V. To interpret the reactions, X-ray diffraction （XRD） and transmission electron microscopy （TEM） are applied. The results show that at the first plateau around 1.4 V, the insertion reaction （COS2 ＋ xNa＊ ＋ xe NaxCoS2） Occurs; while at the second plateau around 0.6 V, the conversion reaction （NaxCoS2 ＋ （4 - x） Na＋ ＋ （4 - x）e -~ Co ＋ 2Na2S） takes place. This provides insights for electrochemical sodium storage of CoS2 as the anode of SIBs.
文摘Electrohydrodynamicjet （E-Jet） is an approach to the fabrication of micro/nano-structures by the use of electrical forces. In this process, the liquid is subjected to electrical and mechanical forces to form a liquid jet, which is further disintegrated into droplets. The major advantage of the E-Jet technique is that the sizes of the jet formed can be at the nanoscale far smaller than the nozzle size, which can realize high printing resolution with less risk of nozzle blockage. The E-Jet technique, which mainly includes E-Jet deposition and E-Jet printing, has a wide range of applications in the fabrication ofmicro/nano-structures for micro/nano-electromechanical system devices. This tech- nique is also considered a micro/nano-fabrication method with a great potential for commercial use. This study mainly reviews the E-Jet deposition/printing fundamentals, fabrication process, and applications.
基金supported by the National Natural Science Foundation (21574004, 21421061, 21434009, 21301036)the National Research Fund for Fundamental Key Projects (2012CB933800)+4 种基金the Fundamental Research Funds for the Central Universitiesthe National “Young Thousand Talents Program”Xiamen Southern Oceanographic Center (14GQT61HJ31)the Key Research Program of the Chinese Academy of Sciences (KJZD-EW-M01, KJZD-EW-M03)the Program of Introducing Talents of Discipline to Universities of China (B14009)
文摘Hydrogels, composed mainly of water trapped in three dimensional cross-linked polymer networks, have been widely utilized to construct underwater superoleophobic surfaces. However, the swelling nature and instability of hydrogels under complex marine environment will weaken their underwater superoleophobicity. Herein, we synthesize structured poly （2-hydroxyethylmethacrylate） （PHEMA） hydrogels by using sandpaper as templates. The robust non-swelling of PHEMA hydrogel ensures that micro/nano-structures on the surface of PHEMA hydrogels can be well maintained. Moreover, when roughness Ra of about 3-4 bun, the surface has superior oil-repellency. Additionally, even after immersing in seawater for one-month, their breaking strength and toughness can be well kept. The non-swellable hydrogels with long-term stable under seawater superoleophobicity will promote the development of robust superoleophobic materials in marine antifouling coatings, biomedical devices and oil/water separation.
基金support from the National MCF Energy R&D Program of China(No.2018YFE0306100).
文摘A novel oxide-dispersion-strengthened(ODS)die steel was fabricated by mechanical alloying and hot consolidation.Annealing and quench-tempering treatments both obtained an ultra-fine grain structure(mean size:310-330 nm)with an ultra-high density of ultra-fine Y-Al-O nano-oxides(number density:~(1-1.5)×10^(23)m^(−3),mean size:5.1-7.2 nm).Prolonged thermal exposure further induced the new,highly dense precipitation of ultra-fine Y-Zr-O nano-oxides.Both nano-oxides tended to be wrapped up with a B2-NiAl nano-shells.Although the quench-tempered sample showed much higher room-temperature strength(yield strength=1393±40 MPa and ultimate tensile strength=1774±11 MPa)and slightly lower elongation(elongation=13.6%±0.6%)than the annealed sample(YS=988±7 MPa,UTS=1490±12 MPa,and EL=15.2%±1.1%),both samples exhibited better strength-ductility synergy at room temperature and much higher thermal stabilities at high temperatures(600-700℃)than all those conventional hot-work die steels,which makes the new ODS steel highly promising for advanced hot-work mold and die applications at high temperatures above 600℃.
文摘In the present work, osteoblast behavior on a hierarchical micro-/nano-structured titanium surface was investigated. A hi- erarchical hybrid micro-/nano-structured titanium surface topography was produced via Electrolytic Etching （EE）. MG-63 cells were cultured on disks for 2 h to 7 days. The osteoblast response to the hierarchical hybrid micro-/nano-structured titanium surface was evaluated through the osteoblast cell morphology, attachment and proliferation. For comparison, MG-63 cells were also cultured on Sandblasted and Acid-etched （SEA） as well as Machined （M） surfaces respectively. The results show signifi- cant differences in the adhesion rates and proliferation levels of MG-63 cells on EE, SLA, and M surfaces. Both adhesion rate and proliferation level on EE surface are higher than those on SLA and M surfaces. Therefore, we may expect that, comparing with SLA and M surfaces, bone growth on EE surface could be accelerated and bone formation could be promoted at an early stage, which could be applied in the clinical practices for immediate and early-stage loadings.
文摘The nano-structural Al-doped ZnO thin films of different morphologies deposited on glass substrate were successfully fabricated at substrate temperature of 350 ℃ by an inexpensive spray pyrolysis method. The structural, electrical, optical and photoluminescence properties were investigated. X-ray diffraction study revealed the crystalline wurtzite （hexagonal） structure of the films with nano-grains. Scanning electron microscopy （SEM） micrographs indicated the formation of a large variety of nano-structures during film growth. The spectral absorption of the films occurred at the absorption edge of -410 nm. In the present study, the optical band gap energy 3.28 eV of ZnO decreased gradually to 3.05 eV for 4 mol% of AI doping. The deep level activation energy decreased and carrier concentrations increased substantially with increasing doping. Exciting with the energy 3.543 eV （A=350 nm）, a narrow and a broad characteristic photoluminescence peaks that correspond to the near band edge （NBE） and deep level emissions （DLE）, respectively emerged.
基金Project supported by the Zhejiang Provincial Natural Science Foundation of China(No.LY14H160016)。
文摘To reduce the problems of poor solubility,high in vivo dosage requirement,and weak targeting ability of paclitaxel(PTX),a hyaluronic acid-octadecylamine(HA-ODA)-modified nano-structured lipid carrier(HA-NLC)was constructed.HA-ODA conjugates were synthesized by an amide reaction between HA and ODA.The hydrophobic chain of HA-ODA can be embedded in the lipid core of the NLC to obtain HA-NLC.The HA-NLC displayed strong internalization in cluster determinant 44(CD44)highly expressed MCF-7 cells,and endocytosis mediated by the CD44 receptor was involved.The HA-NLC had an encapsulation efficiency of PTX of 72.0%.The cytotoxicity of the PTXloaded nanoparticle HA-NLC/PTX in MCF-7 cells was much stronger than that of the commercial preparation Taxol.In vivo,the HA-NLC exhibited strong tumor targeting ability.The distribution of the NLCs to the liver and spleen was reduced after HA modification,while more nanoparticles were aggregated to the tumor site.Our results suggest that HA-NLC has excellent properties as a nano drug carrier and potential for in vivo targeting.
文摘Nano-structured SiO2 thin films were prepared on the surface of carbon steel for the first time by LPD. The compositions of the films were analyzed by XPS, and the surface morphology of the thin films were observed by AFM. The thin films were constituted by compact particles of SiO2, and there was no Fe in the films. In the process of film forming, the SiO2 colloid particles were deposited or absorbed directly onto the surface of carbon steel substrates that were activated by acid solution containing inhibitor, and corrosion of the substrates was avoided. The nano-structured SiO2 thin films that were prepared had excellent protective efficiency to the carbon steel.
基金financially supported by the Jiangxi Provincial Science and Technology Department(No.20151BDH80082)the China National Major Science and Technology Project(No.2014ZX07214-002)the financial support from China Postdoctoral Science Foundation(No.2015M581608)
文摘A bulk nanostructured twinning-induced plasticity （TWIP） steel with high ductility and high strength was fabricated by cryogenic asymmetry-rolling （cryo-ASR） and subsequent recovery treatment. It was found that the cryo-ASRed TWIP steels exhibit simultaneous improvements in the ductility, strength and work hardening. Typical microstructures of the cryo-ASR TWIP steel were characterized by shear bands and intensive mechanical nano-sized twins induced by cryogenic deformation. These mechanical nano-scale twins remain thermally stable during the subsequent recovery treatment. It is believed that the ductility enhancement and high work-hardening ability for the cryo-ASR TWIP steels should be mainly attributed to the high-densitv pre-existing nano-scale twins.
文摘There exist strong interests of developing nano-grained steels because of the outstanding properties including high strength/weight ratio, wear resistance, excellent toughness, and favorable cellular activity. This article reviews the main fabrication process and microstructural control of nano-structured steels over the last decades. Severe plastic deformation is considered as an effective route of obtaining the nano-grained microstructures. The process of cold-rolling and annealing of martensitic steel is a viable method to obtain bulk nano-structured low carbon steel, while the final thickness of the cold-rolling plate is limited. According to the theoretical results of the thermal simulation studies, a novel alloy design combined with the rapid transformation and rolling process is proposed to successfully fabricate nano-grained high strength bulk steel. The refinement mechanisms are expected to be taking advantage of increase in the transformation nucleation sites and inhibiting the grain coarsening. Moreover, corresponding mechanical properties are summarized.
基金Project(10804101) supported by the National Natural Science Foundation of ChinaProject(2007CB815102) supported by the National Basic Research Program of ChinaProject(2007B08007) supported by the Science and Technology Development Foundation of Chinese Academy of Engineering Physics
文摘Silver nano-particles with average diameter of about 60 nm were compacted in a high-strength mold under different pressures at 523 K to produce nano-structured Ag solid materials. The structure and characteristic of the nano-structured Ag solid materials (NSS-Ag) were studied using X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman spectrometer. The NSS-Ag could be used as highly efficient surface-enhanced Raman scattering (SERS) active substrates. The common probe molecules Rhodamine 6G (R6G, 1×10-10 mol/L) were used to test the SERS activity on these substrates at very low concentrations. It is found that the SERS enhancement ability is dependent on the density of NSS-Ag. When the relative density of NSS-Ag is 83.87%, the materials reveal great SERS signal.
文摘The initial field electron emission degradation behaviour of original nano-structured sp^2-bonded amorphous carbon films has been observed, which can be attributed to the increase of the work function of the film in the field emission process analysed using a Fowler-Nordheim plot. The possible reason for the change of work function is suggested to be the desorption of hydrogen from the original hydrogen termination film surface due to field emission current-induced local heating. For the explanation of the emission degradation behaviour of the nano-structured sp2-bonded amorphous carbon film, a cluster model with a series of graphite （0001） basal surfaces has been presented, and the theoretical calculations have been performed to investigate work functions of graphite （0001） surfaces with different hydrogen atom and ion chemisorption sites by using first principles method based on density functional theory-local density approximation.
基金This work was financially supported by the National Climbing Programme of China (No. 1999-444)the Natural Science Foundation of Tianjin (No.003805611 and 033610611) the Center of Liuhui Application Mathematics of Nankai University and Tianjin Univers
文摘Cu-Zn-Al alloy of one dimensional nano-structure was prepared and thestructure of obtained nano-material was characterized by transmission electron microscope (TEM). Itwas shown that there are non-linear oscillations on the surface of Cu-Zn-Al alloy and theconsanguineous connection exists between non-linear oscillation and the growth process of onedimensional nano-structure. The diameter of one dimensional nano-structure is about 40 nm, and theratio of length to diameter is over 40. Finally, the growth mechanism of one dimensionalnano-structure was also studied.
基金financially suppor ted by the National MCF Energy R&D Program of China(Project No.2018YFE0306100)the National Natural Science Foundation of China(No.51971249)。
文摘First-principles energetics analyses were performed to investigate the nucleation of(Y-Si-O)nano-clusters(NCs)in nanostructured ferritic alloys(NFAs).It was predicted that the nucleation of(Y-Si-O)NCs follows the same general pathway as previously found for(Y-Ti/Al/Zr-O)NCs in NFAs:they all tend to begin with the(O-O)pairs and grow to(O-Y)-cores and further to larger NCs by attracting Y and other solute elements nearby.Nucleation of a hexa-atomic-[2Y-Si-3O]-cluster can reduce the total energy by 4.71 eV.Among various microalloying-induced NCs,the nucleation preference ordering was predicted as(Y-Zr-O)>(Y-Ti-O)>(Y-Al-O)>(Y-Si-O).The number densities and chemical compositions of NCs in multi-microalloyed NFAs would largely depend on the number availability of(O,Y)-cores,as well as the relative abundance and atomic diffusivities of microalloying solute elements nearby.
基金supported by the Research and Technology Directorate of National Iranian Oil Company
文摘Cobalt supported on carbon nanotubes （CNTs）-covered alumina has been recently developed and successfully utilized as a catalyst in Fischer-Tropsch synthesis （FTS）. Problems associated with shaping of Co/CNTs into extrudates or pellets as well as catalyst attrition rendered these materials unfavorable for industrial applications. In this investigation regular γ- and nano-structured （N-S） alumina as well as CNTs-covered regular γ- and N-S-alumina supports were impregnated by cobalt nitrate solution to make new cobalt-based catalysts which were also promoted by Ru. The catalysts were characterized and tested in a micro reactor to evaluate their applicability in FTS. γ-Al2O3 was prepared by calcination of bohemite and N-S-Al2O3 was prepared by sol-gel method using aluminum chloride as starting material. Catalyst evaluations indicated that N-S-Al2O3 was superior to regular γ-Al2O3 and that CNTs-covered alumina supports were favored over non-covered ones in terms of activity and heavy hydrocarbon selectivity. These were justified by porosimetric characteristics of the catalysts and existence of CNTs points of view. CNTs-covered catalysts also showed higher wax selectivity and better resistance to deactivation. Furthermore, TPR analysis indicated that the cobalt aluminate phase, which is responsible for the permanent deactivation of alumina supported Co-based catalysts, did not form on alumina supported Co-based catalysts covered with CNTs due to weaker interactions between cobalt and alumina.
文摘It was reported that due to the non-linear electrical phenomena,the super-saturated arsenic in silicon single crystalline precipitates during post processing at low temperatures to form different structures.The structure with spatial period of 1.7 to 2.3 nm was observed firstly by TEM on the sample.
