Nanostructural γ-Ni-28Fe alloy(nano γ-Ni-28Fe)was successfully prepared by mechanochemical alloying(MCA).The relationship between the microstructure and the synthesis conditions was investigated by using XRD,TEM,SEM...Nanostructural γ-Ni-28Fe alloy(nano γ-Ni-28Fe)was successfully prepared by mechanochemical alloying(MCA).The relationship between the microstructure and the synthesis conditions was investigated by using XRD,TEM,SEM as well as BET analyzer.The results show that nano γ-Ni-28Fe alloy is composed of a gamma phase(FCC structure).Its grain size is about 20 nm at reduction temperature below 600 ℃.The magnetic measurements indicate that the saturation magnetization of nano γ-Ni-28Fe alloy is 102.4 A·m2/kg,and the coercivity is much higher than that of conventional coarse-grained counterpart.The result may be attributed to its decrease of the grain size and chemical composition in nano γ-Ni-28Fe alloy.展开更多
Extremely valuable mechanical properties in combination with acceptable wear resistance can make nanostructural bainitic steels to be used extensively in different engineering and tribological applications. However, i...Extremely valuable mechanical properties in combination with acceptable wear resistance can make nanostructural bainitic steels to be used extensively in different engineering and tribological applications. However, it is critical to characterize the contributed factors to investigate the wear response of these high-strength materials. This work aims to study the wear behavior of two nanostructural bainitic steels with different amount of austenite stabilizer elements Mn and Ni. For this purpose, wear resistances of the materials were evaluated using the pin-on-disk method. The results indicated that the hardness of the sample is a critical factor affecting the tribological behavior, and the volume fraction and morphology of high-carbon retained austenite are also of considerable importance. It has also been demonstrated that transformation-induced plasticity effect during the wear test and oxide formation at worn surfaces are critical factors.展开更多
Layered double hydroxides(LDHs), as a class of typical two-dimensional materials, have sparked increasing interest in the field of energy storage and conversion. In the last few years, the research about LDHs as elect...Layered double hydroxides(LDHs), as a class of typical two-dimensional materials, have sparked increasing interest in the field of energy storage and conversion. In the last few years, the research about LDHs as electrode active materials has seen much progress in terms of structure designing, material synthesis, properties tailoring, and applications. In this review, we focus on the integrated nanostructural electrodes(INEs) construction using LDH materials, including pristine LDH-INEs, hybrid LDH-INEs, and LDH derivativeINEs, as well as the performance advantages and applications of LDH-INEs.Moreover, in the final section, the insights about challenges and prospective in this promising research field were concluded, especially in regulation of intrinsic activity and uncovering of structure–activity relationship, which would push forward the development of this fast-growing field.展开更多
Oxygenated fuel represents an attractive alternative as an additive for reducing soot emissions.Dimethyl carbonate（DMC） is an oxygenated compound which is a good option to reduce soot,but the detailed characteristic...Oxygenated fuel represents an attractive alternative as an additive for reducing soot emissions.Dimethyl carbonate（DMC） is an oxygenated compound which is a good option to reduce soot,but the detailed characteristics of soot produced from combustion of hydrocarbon fuels blended with DMC are still lacking. The present research studied the nanostructure and reactivity of soot particles in ethylene/DMC normal and inverse diffusion flames. High resolution transmission electron microscopy（HRTEM）, X-ray diffraction（XRD）, and thermogravimetric analysis（TGA）were used to analyze the nanostructure and reactivity of soot. It was found that DMC addition was effective in decreasing the average weights of soot formed in flames. The results of HRTEM images showed that soot particles obtained with DMC addition showed liquid-like material and tight bonding, and exhibited more highly disorganized layers, which give it higher reactivity than soot obtained without DMC addition. Furthermore, HRTEM was used to analyze soot fringe characteristics consisting of fringe tortuosity, fringe length, and fringe separation. XRD was used to crosscheck the results for fringe separation, and was consistent with HRTEM results. In addition, the mass loss curve of TGA experiments showed that DMC addition could enhance the reactivity of soot particles.展开更多
Nanostructural monophase LaxBi2-xSeyTe3-y alloy was synthesized with a hydrothermal route using BiCl3, LaCl3, selenium and tellurium powders as the precursors, NaOH and disodium ethylenediaminetetraacetiate （EDTA） ...Nanostructural monophase LaxBi2-xSeyTe3-y alloy was synthesized with a hydrothermal route using BiCl3, LaCl3, selenium and tellurium powders as the precursors, NaOH and disodium ethylenediaminetetraacetiate （EDTA） as the additives. The hydrothermally synthesized powders have a petal-like morphology self-structured by the parallel side-by-side arrangement of the nano-scales. It is found that an alkaline additive is necessary for the synthesis of a monophase Bi2Te3 based alloy.展开更多
Size and morphology are critical factors in determining the electrochemical performance of the supercapacitor materials,due to the manifestation of the nanosize effect.Herein,different nanostructures of the CrN materi...Size and morphology are critical factors in determining the electrochemical performance of the supercapacitor materials,due to the manifestation of the nanosize effect.Herein,different nanostructures of the CrN material are prepared by the combination of a thermal-nitridation process and a template technique.High-temperature nitridation could not only transform the hexagonal Cr_(2)O_(3)into cubic CrN,but also keep the template morphology barely unchanged.The obtained CrN nanostructures,including(i)hierarchical microspheres assembled by nanoparticles,(ii)microlayers,and(iii)nanoparticles,are studied for the electrochemical supercapacitor.The CrN microspheres show the best specific capacitance(213.2 F/g),cyclic stability(capacitance retention rate of 96%after 5000 cycles in 1-mol/L KOH solution),high energy density(28.9 Wh/kg),and power density(443.4 W/kg),comparing with the other two nanostructures.Based on the impedance spectroscopy and nitrogen adsorption analysis,it is revealed that the enhancement arised mainly from a high-conductance and specific surface area of CrN microspheres.This work presents a general strategy of fabricating controllable CrN nanostructures to achieve the enhanced supercapacitor performance.展开更多
Titanium nitride （TIN） films with nanostructure were prepared at ambient temperature on a （111） silicon substrate by the filtered cathodic arc plasma （FCAP） technology with an in-plane ＂S＂ filter. The effects ...Titanium nitride （TIN） films with nanostructure were prepared at ambient temperature on a （111） silicon substrate by the filtered cathodic arc plasma （FCAP） technology with an in-plane ＂S＂ filter. The effects of deposition parameters on the grain size, texture and nano-hardness of the films were systematically investigated. The grain size was obtained through calculation using the Scherrer formula and observed by TEM. The results of X-ray diffraction and electron diffraction indicated that increasing either negative substrate bias or argon flow promoted the formation of （111） preferred orientation. High argon flow leads to biaxial texture. The micro-hardness of the TIN films as a function of grain size showed a behavior according to the Hall-Petch relation under high argon flow.展开更多
CdSe/CTAB composite nanostructural materials were successfully synthesized at 160-200℃ for 2 days through a facile surfactant （cetyl trimethyl ammonium bromide-CTAB） assisted hydrothermal method us- ing cadmium ace...CdSe/CTAB composite nanostructural materials were successfully synthesized at 160-200℃ for 2 days through a facile surfactant （cetyl trimethyl ammonium bromide-CTAB） assisted hydrothermal method us- ing cadmium acetate and sodium selenate as precursor. The obtained products were characterized by X-ray diffraction, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy and thermo gravimetric analysis. Optical properties were studied by photoluminescence and UV-visible spectroscopy and morphology was investigated by scanning electron microscopy.展开更多
By heating pure zinc powder at low tenlperature, two kinds of ZnO nanostructures with different mor phology and diameter were grown on silicon （100） substrates. Scanning electron microscopy images show that ZnO nano...By heating pure zinc powder at low tenlperature, two kinds of ZnO nanostructures with different mor phology and diameter were grown on silicon （100） substrates. Scanning electron microscopy images show that ZnO nanorods and ZnO nanowires have been obtained. XRD dem onstrates that the grown ZnO nanostructures are hexagonal wurtzite crystalline. The electron field emission properties were studied for both kinds of samples. The ZnO nanorods sample has a low turn-on field at 3.6 V/μm owing to better alignment, while the field to obtain a current density of 1mA·cm^-2 is higher （at 11. 2 V/μm） than that of the nanowires sample due to bigger diameter. For nanowires sampie, an emission current of 1 mA·cm^-2 is achieved at 8.2 V/μm which is Lower than that of ZnO nanorods owing to belier high aspect ratio.展开更多
The poor surface conditions and osseointegration capacity of 3D printed Ti6Al4V implants(3DPT)significantly influence their performance as orthopedic and dental implants.In this work,we creatively introduce a one-step...The poor surface conditions and osseointegration capacity of 3D printed Ti6Al4V implants(3DPT)significantly influence their performance as orthopedic and dental implants.In this work,we creatively introduce a one-step femtosecond laser treatment to improve the surface conditions and osteointegration.The surface characterization,mechanical properties,corrosion resistance,and biological responses were investigated.These results found that femtosecond laser eliminated defects like embedded powders and superficial cracks while forming the nano cones-like structures surface on 3DPT,leading to enhanced osseointegration,anti-corrosion,and anti-fatigue performance.Molecular dynamics simulations revealed the ablation removal mechanism and the formation of nano cone-like structures.These findings were further supported by the in vivo studies,showing that the FS-treated implants had superior bone-implant contact and osseointegration.Hence,the one-step femtosecond laser method is regarded as a promising surface modification method for improving the functional performance of Ti-based orthopedic implants.展开更多
For the development of high-performance metallic glasses,enhancing their stability against viscous flow and crystallization is a primary objective.Vapor deposition or prolonged annealing is an effective method to impr...For the development of high-performance metallic glasses,enhancing their stability against viscous flow and crystallization is a primary objective.Vapor deposition or prolonged annealing is an effective method to improve glass stability,shown by increased glass transition temperature(Tg)and crystallization temperature(Tx).This contributes to the development of ultra-stable metallic glasses.Herein,we demonstrate that modulating the quenching temperature can also produce ultra-stable metallic glasses,as evidenced by an increase in Tx of 17-30 K in Cu-based metallic glasses.By modulating the quenching temperature,separated primary phases,secondary phases,and even nano-oxides can be obtained in the metallic glasses.Notably,metastable phases such as Cu-rich precipitates arising from secondary phase separation play a crucial role in enhancing glass stability.However,the enhancement of the stability of the glass has only a negligible effect on its mechanical properties.This study implies that different melt thermodynamic states generated by liquid-liquid separation and transition collectively determine the frozen-in glass structure.The results of this study will be helpful for the development of ultra-stable bulk glasses.展开更多
Constructing a framework carrier to stabilize protein conformation,induce high embedding efficiency,and acquire low mass-transfer resistance is an urgent issue in the development of immobilized enzymes.Hydrogen-bonded...Constructing a framework carrier to stabilize protein conformation,induce high embedding efficiency,and acquire low mass-transfer resistance is an urgent issue in the development of immobilized enzymes.Hydrogen-bonded organic frameworks(HOFs)have promising application potential for embedding enzymes.In fact,no metal involvement is required,and HOFs exhibit superior biocompatibility,and free access to substrates in mesoporous channels.Herein,a facile in situ growth approach was proposed for the self-assembly of alcohol dehydrogenase encapsulated in HOF.The micron-scale bio-catalytic composite was rapidly synthesized under mild conditions(aqueous phase and ambient temperature)with a controllable embedding rate.The high crystallinity and periodic arrangement channels of HOF were preserved at a high enzyme encapsulation efficiency of 59%.This bio-composite improved the tolerance of the enzyme to the acid-base environment and retained 81%of its initial activity after five cycles of batch hydrogenation involving NADH coenzyme.Based on this controllably synthesized bio-catalytic material and a common lipase,we further developed a two-stage cascade microchemical system and achieved the continuous production of chiral hydroxybutyric acid(R-3-HBA).展开更多
The intermetallic compounds based on the tetragonal ThMn_(12) prototype crystal structure have exhibited great potential as advanced rare-earth-lean permanent magnets due to their excellent intrinsic magnetic properti...The intermetallic compounds based on the tetragonal ThMn_(12) prototype crystal structure have exhibited great potential as advanced rare-earth-lean permanent magnets due to their excellent intrinsic magnetic properties.However,the trade-off between the phase stability and the magnetic performance is often encountered in the ThMn_(12)-type magnets.This work was focused on the effects of V doping and nanos-tructuring on the phase stability and magnetic properties of ThMn_(12)-type Sm-Co-based magnets.Novel SmCo_(12)-based nanocrystalline alloys with the SmCo_(12) main phase were prepared for the first time.The prepared alloys from the optimal design achieved obviously higher coercivity than the isotropic SmFe_(12)-based alloys,together with comparable performance of other magnetic features.The enhancement in the coercivity was ascribed to the pinning of domain walls by the nanocrystalline grain boundaries and stacking faults.First-principles calculations and magnetic structure analysis disclosed that V substitution can stabilize the SmCo_(12) lattice and elevate its magnetocrystalline anisotropy.This study provides a new approach to developing stabilized metastable structured rare-earth-lean alloys with high magnetic per-formance.展开更多
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 Results Molecular self-assembly of one-/two-dimensional (1D/2D) nanostructures has recently received great interest because the specific structures of crystals determine their unique physical and chemical properties...1 Results Molecular self-assembly of one-/two-dimensional (1D/2D) nanostructures has recently received great interest because the specific structures of crystals determine their unique physical and chemical properties. Coordination polymers contain two central components, connectors and linkers. Transition metal ions are often used as versatile connectors, with coordination numbers ranging from 2 to 7 dependant on the oxidation states of the metal ions. Multidentate ligands are often used as linkers, wh...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
Text mining has emerged as a powerful strategy for extracting domain knowledge structure from large amounts of text data.To date,most text mining methods are restricted to specific literature information,resulting in ...Text mining has emerged as a powerful strategy for extracting domain knowledge structure from large amounts of text data.To date,most text mining methods are restricted to specific literature information,resulting in incomplete knowledge graphs.Here,we report a method that combines citation analysis with topic modeling to describe the hidden development patterns in the history of science.Leveraging this method,we construct a knowledge graph in the field of Raman spectroscopy.The traditional Latent DirichletAllocation model is chosen as the baseline model for comparison to validate the performance of our model.Our method improves the topic coherence with a minimum growth rate of 100%compared to the traditional text mining method.It outperforms the traditional text mining method on the diversity,and its growth rate ranges from 0 to 126%.The results show the effectiveness of rule-based tokenizer we designed in solving the word tokenizer problem caused by entity naming rules in the field of chemistry.It is versatile in revealing the distribution of topics,establishing the similarity and inheritance relationships,and identifying the important moments in the history of Raman spectroscopy.Our work provides a comprehensive tool for the science of science research and promises to offer new insights into the historical survey and development forecast of a research field.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
Precise tumor targeting and therapy is a major trend in cancer treatment.Herein,we designed a tumor acidic microenvironment activatable drug loaded DNA nanostructure,in which,we made a clever use of the sequences of A...Precise tumor targeting and therapy is a major trend in cancer treatment.Herein,we designed a tumor acidic microenvironment activatable drug loaded DNA nanostructure,in which,we made a clever use of the sequences of AS1411 and i-motif,which can partially hybridize,and designed a simple while robust DNA D-strand nanostructure,in which,i-motif sequence was designed to regulate the binding ability of the AS1411 aptamer to target tumor.In the normal physiological environment,i-motif inhibits the targeting ability of AS1411.In the acidic tumor microenvironment,i-motif forms a quadruplex conformation and dissociates from AS1411,restoring the targeting ability of AS1411.Only when acidic condition and tumor cell receptor are present,this nanostructure can be internalized by the tumor cells.Moreover,the structure change of this nanostructure can realize the release of loaded drug.This drug loaded A-I-Duplex DNA structure showed cancer cell and spheroid targeting and inhibition ability,which is promising in the clinical cancer therapy.展开更多
Osteogenic ability impairment and myelosuppression are common complications of chemotherapy and many chemotherapeutics can affect the skeletal system.Skeletal system protection is necessary for cancer chemotherapy.In ...Osteogenic ability impairment and myelosuppression are common complications of chemotherapy and many chemotherapeutics can affect the skeletal system.Skeletal system protection is necessary for cancer chemotherapy.In this study,osteogenic growth peptide(OGP)and tetrahedral framework nucleic-acid nanostructures(tFNAs)are combined to form a peptide-DNA complex OGP-tFNAs,which aims to combine the positive biological effect on tissue protection and regeneration.The bone marrow protection and bone formation effect of OGP-tFNAs are investigated in chemotherapy-induced myelosuppressive mice.The results show that OGP-tFNAs could reduce the cell damage degree from 5-fluorouracil(5-FU)in vitro and maintained the osteogenic differentiation potential.Furthermore,OGP-tFNAs accelerate bone defect regeneration in myelosuppressive mice.In conclusion,OGP-tFNAs could protect the osteogenic differentiation potential of bone marrow stromal cells(BMSCs)from 5-FU injury and maintain the bone formation ability of myelosuppressive mice suffering from chemotherapy.展开更多
基金Project(2003jq158) supported by the Hundred Person Program of Chinese Academy of ScienceProject(2006jq1071) supported by the Younger Teacher Foundation of High Education School of Anhui Province,China
文摘Nanostructural γ-Ni-28Fe alloy(nano γ-Ni-28Fe)was successfully prepared by mechanochemical alloying(MCA).The relationship between the microstructure and the synthesis conditions was investigated by using XRD,TEM,SEM as well as BET analyzer.The results show that nano γ-Ni-28Fe alloy is composed of a gamma phase(FCC structure).Its grain size is about 20 nm at reduction temperature below 600 ℃.The magnetic measurements indicate that the saturation magnetization of nano γ-Ni-28Fe alloy is 102.4 A·m2/kg,and the coercivity is much higher than that of conventional coarse-grained counterpart.The result may be attributed to its decrease of the grain size and chemical composition in nano γ-Ni-28Fe alloy.
基金Sahand University of Technology, Tabriz, Iran, for supporting and providing the research facilities
文摘Extremely valuable mechanical properties in combination with acceptable wear resistance can make nanostructural bainitic steels to be used extensively in different engineering and tribological applications. However, it is critical to characterize the contributed factors to investigate the wear response of these high-strength materials. This work aims to study the wear behavior of two nanostructural bainitic steels with different amount of austenite stabilizer elements Mn and Ni. For this purpose, wear resistances of the materials were evaluated using the pin-on-disk method. The results indicated that the hardness of the sample is a critical factor affecting the tribological behavior, and the volume fraction and morphology of high-carbon retained austenite are also of considerable importance. It has also been demonstrated that transformation-induced plasticity effect during the wear test and oxide formation at worn surfaces are critical factors.
基金supported by the National Natural Science Foundation of China(21601011 and 21521005)the National Key Research and Development Programme(2017YFA0206804)+1 种基金the Fundamental Research Funds for the Central Universities(buctrc201506 and buctylkxj01)the Higher Education and HighQuality and World-Class Universities(PY201610)
文摘Layered double hydroxides(LDHs), as a class of typical two-dimensional materials, have sparked increasing interest in the field of energy storage and conversion. In the last few years, the research about LDHs as electrode active materials has seen much progress in terms of structure designing, material synthesis, properties tailoring, and applications. In this review, we focus on the integrated nanostructural electrodes(INEs) construction using LDH materials, including pristine LDH-INEs, hybrid LDH-INEs, and LDH derivativeINEs, as well as the performance advantages and applications of LDH-INEs.Moreover, in the final section, the insights about challenges and prospective in this promising research field were concluded, especially in regulation of intrinsic activity and uncovering of structure–activity relationship, which would push forward the development of this fast-growing field.
基金supported by the National Natural Science Foundation of China(No.51576100)the Jiangsu Provincial Innovative Project of Graduate Education(No.KYZZ16_0184)the Jiangsu Provincial Project of "Six Talent Summit"(No.2014-XNY-002)
文摘Oxygenated fuel represents an attractive alternative as an additive for reducing soot emissions.Dimethyl carbonate（DMC） is an oxygenated compound which is a good option to reduce soot,but the detailed characteristics of soot produced from combustion of hydrocarbon fuels blended with DMC are still lacking. The present research studied the nanostructure and reactivity of soot particles in ethylene/DMC normal and inverse diffusion flames. High resolution transmission electron microscopy（HRTEM）, X-ray diffraction（XRD）, and thermogravimetric analysis（TGA）were used to analyze the nanostructure and reactivity of soot. It was found that DMC addition was effective in decreasing the average weights of soot formed in flames. The results of HRTEM images showed that soot particles obtained with DMC addition showed liquid-like material and tight bonding, and exhibited more highly disorganized layers, which give it higher reactivity than soot obtained without DMC addition. Furthermore, HRTEM was used to analyze soot fringe characteristics consisting of fringe tortuosity, fringe length, and fringe separation. XRD was used to crosscheck the results for fringe separation, and was consistent with HRTEM results. In addition, the mass loss curve of TGA experiments showed that DMC addition could enhance the reactivity of soot particles.
文摘Nanostructural monophase LaxBi2-xSeyTe3-y alloy was synthesized with a hydrothermal route using BiCl3, LaCl3, selenium and tellurium powders as the precursors, NaOH and disodium ethylenediaminetetraacetiate （EDTA） as the additives. The hydrothermally synthesized powders have a petal-like morphology self-structured by the parallel side-by-side arrangement of the nano-scales. It is found that an alkaline additive is necessary for the synthesis of a monophase Bi2Te3 based alloy.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11904299,U1930124,and 11804312)China Academy of Engineering Physics(CAEP)Foundation(Grant No.2018AB02)。
文摘Size and morphology are critical factors in determining the electrochemical performance of the supercapacitor materials,due to the manifestation of the nanosize effect.Herein,different nanostructures of the CrN material are prepared by the combination of a thermal-nitridation process and a template technique.High-temperature nitridation could not only transform the hexagonal Cr_(2)O_(3)into cubic CrN,but also keep the template morphology barely unchanged.The obtained CrN nanostructures,including(i)hierarchical microspheres assembled by nanoparticles,(ii)microlayers,and(iii)nanoparticles,are studied for the electrochemical supercapacitor.The CrN microspheres show the best specific capacitance(213.2 F/g),cyclic stability(capacitance retention rate of 96%after 5000 cycles in 1-mol/L KOH solution),high energy density(28.9 Wh/kg),and power density(443.4 W/kg),comparing with the other two nanostructures.Based on the impedance spectroscopy and nitrogen adsorption analysis,it is revealed that the enhancement arised mainly from a high-conductance and specific surface area of CrN microspheres.This work presents a general strategy of fabricating controllable CrN nanostructures to achieve the enhanced supercapacitor performance.
基金[This work was supported by the National Natural Science Foundation of China (No. 20571042) and the Natural Science Foundation of Henan University (No. 04YBRW056).]
文摘Titanium nitride （TIN） films with nanostructure were prepared at ambient temperature on a （111） silicon substrate by the filtered cathodic arc plasma （FCAP） technology with an in-plane ＂S＂ filter. The effects of deposition parameters on the grain size, texture and nano-hardness of the films were systematically investigated. The grain size was obtained through calculation using the Scherrer formula and observed by TEM. The results of X-ray diffraction and electron diffraction indicated that increasing either negative substrate bias or argon flow promoted the formation of （111） preferred orientation. High argon flow leads to biaxial texture. The micro-hardness of the TIN films as a function of grain size showed a behavior according to the Hall-Petch relation under high argon flow.
文摘CdSe/CTAB composite nanostructural materials were successfully synthesized at 160-200℃ for 2 days through a facile surfactant （cetyl trimethyl ammonium bromide-CTAB） assisted hydrothermal method us- ing cadmium acetate and sodium selenate as precursor. The obtained products were characterized by X-ray diffraction, energy dispersive X-ray analysis, Fourier transform infrared spectroscopy and thermo gravimetric analysis. Optical properties were studied by photoluminescence and UV-visible spectroscopy and morphology was investigated by scanning electron microscopy.
基金Supported by the National Natural Science Founda-tion of China (19975035)
文摘By heating pure zinc powder at low tenlperature, two kinds of ZnO nanostructures with different mor phology and diameter were grown on silicon （100） substrates. Scanning electron microscopy images show that ZnO nanorods and ZnO nanowires have been obtained. XRD dem onstrates that the grown ZnO nanostructures are hexagonal wurtzite crystalline. The electron field emission properties were studied for both kinds of samples. The ZnO nanorods sample has a low turn-on field at 3.6 V/μm owing to better alignment, while the field to obtain a current density of 1mA·cm^-2 is higher （at 11. 2 V/μm） than that of the nanowires sample due to bigger diameter. For nanowires sampie, an emission current of 1 mA·cm^-2 is achieved at 8.2 V/μm which is Lower than that of ZnO nanorods owing to belier high aspect ratio.
基金supported by the National Natural Science Foundation of China(No.U21A2055),Natural Science Foundation of Tianjin of China(No.21JCQNJC01280)Tianjin Key R&D Program Beijing-Tianjin-Hebei Collaborative Innovation Project(No.22YFXTHZ00120).
文摘The poor surface conditions and osseointegration capacity of 3D printed Ti6Al4V implants(3DPT)significantly influence their performance as orthopedic and dental implants.In this work,we creatively introduce a one-step femtosecond laser treatment to improve the surface conditions and osteointegration.The surface characterization,mechanical properties,corrosion resistance,and biological responses were investigated.These results found that femtosecond laser eliminated defects like embedded powders and superficial cracks while forming the nano cones-like structures surface on 3DPT,leading to enhanced osseointegration,anti-corrosion,and anti-fatigue performance.Molecular dynamics simulations revealed the ablation removal mechanism and the formation of nano cone-like structures.These findings were further supported by the in vivo studies,showing that the FS-treated implants had superior bone-implant contact and osseointegration.Hence,the one-step femtosecond laser method is regarded as a promising surface modification method for improving the functional performance of Ti-based orthopedic implants.
基金supported by the National Natural Science Foundation of China(Nos.51827801,52371152,and 51971120).
文摘For the development of high-performance metallic glasses,enhancing their stability against viscous flow and crystallization is a primary objective.Vapor deposition or prolonged annealing is an effective method to improve glass stability,shown by increased glass transition temperature(Tg)and crystallization temperature(Tx).This contributes to the development of ultra-stable metallic glasses.Herein,we demonstrate that modulating the quenching temperature can also produce ultra-stable metallic glasses,as evidenced by an increase in Tx of 17-30 K in Cu-based metallic glasses.By modulating the quenching temperature,separated primary phases,secondary phases,and even nano-oxides can be obtained in the metallic glasses.Notably,metastable phases such as Cu-rich precipitates arising from secondary phase separation play a crucial role in enhancing glass stability.However,the enhancement of the stability of the glass has only a negligible effect on its mechanical properties.This study implies that different melt thermodynamic states generated by liquid-liquid separation and transition collectively determine the frozen-in glass structure.The results of this study will be helpful for the development of ultra-stable bulk glasses.
基金supported by the National Key Research and Development Program of China(2019YFA0905100)the National Natural Science Foundation of China(21991102,22378227).
文摘Constructing a framework carrier to stabilize protein conformation,induce high embedding efficiency,and acquire low mass-transfer resistance is an urgent issue in the development of immobilized enzymes.Hydrogen-bonded organic frameworks(HOFs)have promising application potential for embedding enzymes.In fact,no metal involvement is required,and HOFs exhibit superior biocompatibility,and free access to substrates in mesoporous channels.Herein,a facile in situ growth approach was proposed for the self-assembly of alcohol dehydrogenase encapsulated in HOF.The micron-scale bio-catalytic composite was rapidly synthesized under mild conditions(aqueous phase and ambient temperature)with a controllable embedding rate.The high crystallinity and periodic arrangement channels of HOF were preserved at a high enzyme encapsulation efficiency of 59%.This bio-composite improved the tolerance of the enzyme to the acid-base environment and retained 81%of its initial activity after five cycles of batch hydrogenation involving NADH coenzyme.Based on this controllably synthesized bio-catalytic material and a common lipase,we further developed a two-stage cascade microchemical system and achieved the continuous production of chiral hydroxybutyric acid(R-3-HBA).
基金supported by the National Key R&D Program of China(Nos.2021YFB3501502 and 2021YFB3501504).
文摘The intermetallic compounds based on the tetragonal ThMn_(12) prototype crystal structure have exhibited great potential as advanced rare-earth-lean permanent magnets due to their excellent intrinsic magnetic properties.However,the trade-off between the phase stability and the magnetic performance is often encountered in the ThMn_(12)-type magnets.This work was focused on the effects of V doping and nanos-tructuring on the phase stability and magnetic properties of ThMn_(12)-type Sm-Co-based magnets.Novel SmCo_(12)-based nanocrystalline alloys with the SmCo_(12) main phase were prepared for the first time.The prepared alloys from the optimal design achieved obviously higher coercivity than the isotropic SmFe_(12)-based alloys,together with comparable performance of other magnetic features.The enhancement in the coercivity was ascribed to the pinning of domain walls by the nanocrystalline grain boundaries and stacking faults.First-principles calculations and magnetic structure analysis disclosed that V substitution can stabilize the SmCo_(12) lattice and elevate its magnetocrystalline anisotropy.This study provides a new approach to developing stabilized metastable structured rare-earth-lean alloys with high magnetic per-formance.
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.
文摘1 Results Molecular self-assembly of one-/two-dimensional (1D/2D) nanostructures has recently received great interest because the specific structures of crystals determine their unique physical and chemical properties. Coordination polymers contain two central components, connectors and linkers. Transition metal ions are often used as versatile connectors, with coordination numbers ranging from 2 to 7 dependant on the oxidation states of the metal ions. Multidentate ligands are often used as linkers, wh...
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supported by the National Natural Science Foundation of China(T2222002,22032004)the Fundamental Research Funds for the Central Universities(Xiamen University:No.20720240053)State Key Laboratory of Vaccines for Infectious Diseases,Xiang An Biomedicine Laboratory(2023XAKJ0103074).
文摘Text mining has emerged as a powerful strategy for extracting domain knowledge structure from large amounts of text data.To date,most text mining methods are restricted to specific literature information,resulting in incomplete knowledge graphs.Here,we report a method that combines citation analysis with topic modeling to describe the hidden development patterns in the history of science.Leveraging this method,we construct a knowledge graph in the field of Raman spectroscopy.The traditional Latent DirichletAllocation model is chosen as the baseline model for comparison to validate the performance of our model.Our method improves the topic coherence with a minimum growth rate of 100%compared to the traditional text mining method.It outperforms the traditional text mining method on the diversity,and its growth rate ranges from 0 to 126%.The results show the effectiveness of rule-based tokenizer we designed in solving the word tokenizer problem caused by entity naming rules in the field of chemistry.It is versatile in revealing the distribution of topics,establishing the similarity and inheritance relationships,and identifying the important moments in the history of Raman spectroscopy.Our work provides a comprehensive tool for the science of science research and promises to offer new insights into the historical survey and development forecast of a research field.
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funded by the National Natural Science Foundation of China(No.32271464)the Hunan Provincial Natural Science Foundation for Distinguished Young Scholars(No.2022JJ10086)+2 种基金the Innovation-Driven Project of Central South University(No.2020CX048)Hunan Provincial High-Level Health Talents(No.20240304088)Fund of the Hunan Provincial Natural Science Foundation and the Hunan Medical Products Administration(No.2023JJ60501)。
文摘Precise tumor targeting and therapy is a major trend in cancer treatment.Herein,we designed a tumor acidic microenvironment activatable drug loaded DNA nanostructure,in which,we made a clever use of the sequences of AS1411 and i-motif,which can partially hybridize,and designed a simple while robust DNA D-strand nanostructure,in which,i-motif sequence was designed to regulate the binding ability of the AS1411 aptamer to target tumor.In the normal physiological environment,i-motif inhibits the targeting ability of AS1411.In the acidic tumor microenvironment,i-motif forms a quadruplex conformation and dissociates from AS1411,restoring the targeting ability of AS1411.Only when acidic condition and tumor cell receptor are present,this nanostructure can be internalized by the tumor cells.Moreover,the structure change of this nanostructure can realize the release of loaded drug.This drug loaded A-I-Duplex DNA structure showed cancer cell and spheroid targeting and inhibition ability,which is promising in the clinical cancer therapy.
基金supported by National Natural Science Foundation of China(Nos.82322015,82171006)Sichuan Province Youth Science and Technology Innovation Team(No.2022JDTD0021)+3 种基金Sichuan Science and Technology Program(No.2022NSFSC0002)West China Hospital of Stomatology Sichuan University(No.RCDWJS2024-3)Sichuan Science and Technology Program(Nos.2023NSFSC1706,2024NSFSC1589)Postdoctoral Science Foundation of China(No.BX20220220)。
文摘Osteogenic ability impairment and myelosuppression are common complications of chemotherapy and many chemotherapeutics can affect the skeletal system.Skeletal system protection is necessary for cancer chemotherapy.In this study,osteogenic growth peptide(OGP)and tetrahedral framework nucleic-acid nanostructures(tFNAs)are combined to form a peptide-DNA complex OGP-tFNAs,which aims to combine the positive biological effect on tissue protection and regeneration.The bone marrow protection and bone formation effect of OGP-tFNAs are investigated in chemotherapy-induced myelosuppressive mice.The results show that OGP-tFNAs could reduce the cell damage degree from 5-fluorouracil(5-FU)in vitro and maintained the osteogenic differentiation potential.Furthermore,OGP-tFNAs accelerate bone defect regeneration in myelosuppressive mice.In conclusion,OGP-tFNAs could protect the osteogenic differentiation potential of bone marrow stromal cells(BMSCs)from 5-FU injury and maintain the bone formation ability of myelosuppressive mice suffering from chemotherapy.
