A gold catalyst of Au/pyrenyl‑graphdiyne(Pyr‑GDY)was prepared by anchoring small size of gold nanoparticles(Au NPs)on the surface of Pyr‑GDY for electrocatalytic nitrogen reduction reaction(eNRR),in which Au NPs with ...A gold catalyst of Au/pyrenyl‑graphdiyne(Pyr‑GDY)was prepared by anchoring small size of gold nanoparticles(Au NPs)on the surface of Pyr‑GDY for electrocatalytic nitrogen reduction reaction(eNRR),in which Au NPs with a size of approximately 3.69 nm was evenly distributed on spongy‑like porous Pyr‑GDY.The catalyst exhibited a good electrocatalytic activity for N_(2)reduction in a nitrogen‑saturated electrolyte,with an ammonia yield of 32.1μg·h^(-1)·mg_(cat)^(-1)at-0.3 V(vs RHE),3.5 times higher than that of Au/C(Au NPs anchored on carbon black).In addition,Au/Pyr‑GDY showed a Faraday efficiency(FE)of 26.9%for eNRR,and a good catalysis durability for over 22 h.展开更多
OBJECTIVE To review the application of nanoparticles modified with angiopep-2,providing theoretical guidance for the diagnosis and treatment of glioma. METHODS According to domestic and foreign research reports of nan...OBJECTIVE To review the application of nanoparticles modified with angiopep-2,providing theoretical guidance for the diagnosis and treatment of glioma. METHODS According to domestic and foreign research reports of nanoparticles modified with angiopep-2 in recent years,the application in the diagnosis and treatment of glioma was summarized and analyzed. RESULTS Angiopep-2 can be modified to the surface of nanoparticles loaded with imaging agents or chemotherapeutic agents,which can significantly improve the imaging effect of glioma and achieve targeted drug delivery. CONCLUSION Angiopep-2 exhibits a high brain penetration capability in blood brain barrier and in glioma cells. The nanoparticles modified with angiopep-2 can delivery various imaging agents and chemotherapeutic agents to glioma cells,the dual-targeting delivery systems can provide theoretical guidance for the diagnosis and treatment of glioma.展开更多
Cotton production substantiated a crucial part in the escalating economic development of many countries.To realize the increasing global demand for cotton,the emphasis should be laid on to improve cotton fiber growth ...Cotton production substantiated a crucial part in the escalating economic development of many countries.To realize the increasing global demand for cotton,the emphasis should be laid on to improve cotton fiber growth and production.The bioengineered transgenic cotton proved expedient in resolving inadequacies of conventional cotton,but still required improvements to encounter heightened demand of textile industries.One possible solution pertaining to this has been provided by nanoscience in the form of metal or metal oxide nanoparticles.These metal oxide nanoparticles have easy access to the various parts of cotton plants through its transportation system,and thus significantly influence several parameters relative to the growth and production of cotton fiber.This review summarizes the distribution and accumulation of metal oxide nanoparticles in cotton plant and its impact on different plant growth-promoting factors,which resulted in the improved cotton yields.展开更多
The catalytic proficiency of three MONs for AP thermal decomposition was studied in this work.A chemical co-precipitation method was used for synthesis of MONs(CuZnO,CoZnO,and NiZnO)and their characterization carried ...The catalytic proficiency of three MONs for AP thermal decomposition was studied in this work.A chemical co-precipitation method was used for synthesis of MONs(CuZnO,CoZnO,and NiZnO)and their characterization carried out by utilizing XRD,FTIR,and SEM.The TGA/DSC technique was employed for the investigation of the catalytic proficiency of MONs on the AP.The DSC data were used for measuring activation energy of catalyzed AP by using Ozawa,Kissinger,and Starink method.The MONs were much sensitive for AP decomposition,and the performance of AP decomposition was further improved.Among all the MONs,the CuZnO exhibits higher catalytic action than others and decomposition temperature of AP is descending around 117℃ by CuZnO.The reduction in the activation energy was noticed after the incorporation of MONs in AP.展开更多
A novel molecularly imprinted polymer (MIP) based on upconversion nanoparticles (UCNPs) was successfully synthesized for determination of Ochratoxin A (OTA). The MIP was developed on the silica-coated UCNPs using N-(1...A novel molecularly imprinted polymer (MIP) based on upconversion nanoparticles (UCNPs) was successfully synthesized for determination of Ochratoxin A (OTA). The MIP was developed on the silica-coated UCNPs using N-(1-hydroxy-2-naphthoyl amido)-(L)-phenylalanine (HNA-Phe) as the alternative template. The final composite combined the advantages of the high selectivity of MIP with the high fluorescence intensity of UCNPs which was selective and sensitive to OTA. Under the optimal condition, the fluorescence intensity of UCNPs@SiO2@MIP decreases linearly when the concentration of OTA increases from 0.05 to 1.0 mg/L. The detection limit of OTA with the method was 0.031 mg/L. At three spiked concentration levels (50, 100 and 200 μg/kg), the recovery ranges of OTA in corn, rice and feed are 88.0%–91.6%, 80.2%–91.6% and 89.2%–90.4%, respectively.展开更多
Superalloys are grouped as hard-to-cut materials with relatively poor machinability.Tool wear is considered one of the main machinability attributes in machining superalloys.Although numerous works have been reported ...Superalloys are grouped as hard-to-cut materials with relatively poor machinability.Tool wear is considered one of the main machinability attributes in machining superalloys.Although numerous works have been reported on factors governing tool life in machining superalloys,no study was found on the effect of nanoparticles stability on nanofluid performance and consequently resulted tool wear morphologies.In the present work,the nanoparticles were reinforced by means of improving the stability of the base fluid.To that accomplished,the surface active agent (surfactant) was added to the base cutting fluid as a reinforcing element.The effects of new lubricant on the tool wear morphology of A286 works parts were assessed.展开更多
Folic acid conjugated chitosan was prepared by cross-linking reaction with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride(EDC), and then used as a template to prepare folic acid-chitosan(FA-CS) conjugate...Folic acid conjugated chitosan was prepared by cross-linking reaction with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride(EDC), and then used as a template to prepare folic acid-chitosan(FA-CS) conjugated nanoparticles and load mitoxantrone nanoparticles(FA-CSNP/MTX). Drug dissolution testing, CCK-8 method, and confocal microscopy were used to detect their controlled-release capability in different situations and the specific uptake by HONE1 cells. The experimental results show that the nanoparticles have uniform size distribution of 48-58 nm. The highest encapsulation rate of the particles on mitoxantrone hydrochloride(MTX) is(77.5±1.9)%, and the drug loading efficiency is(18.4±0.4)%. The sustained release effect, cell growth inhibition activity and targeting effect of the FA-CS/MTX nanoparticles are good in artificial gastric fluid and intestinal fluid. It is demonstrated that the FA-CSNP system is a potentially useful system for the targeted delivery of anticancer drug MTX.展开更多
Properties of hydroxyapatite （HA, Ca10（PO4）6（OH）2）, including bioactivity, biocompatibility, solubility and adsorption could be tailored over wide ranges by the control of particle composition, particle size and...Properties of hydroxyapatite （HA, Ca10（PO4）6（OH）2）, including bioactivity, biocompatibility, solubility and adsorption could be tailored over wide ranges by the control of particle composition, particle size and morphology. In order to satisfy various applications, well-crystallized pure HA nanoparticles were synthesized at moderate temperatures by hydrotherrnal synthesis, and HA nanoparticles with different lengths were obtained by adding organic additives. X-ray diffractometry （XRD） and Fourier transform infrared （FTIR） spectrometry were used to characterize these nanoparticles, and the morphologies of the HA particles were observed by transmission electron microscopy （TEM）. The results demonstrate that shorter rod-like HA particles can be prepared by adding cetyltrimethylammonium bromide （CTAB）, as the additive of CTAB can block the HA crystal growth along with c-axis. And whisker HA particles are obtained by adding ethylenediamine tetraacetic acid （EDTA）, since EDTA may have effect on the dissolution-repreeipitation process of HA.展开更多
Rational design and synthesis of non-precious-metal catalyst plays an important role in improving the activity and stability for oxygen reduction reaction(ORR)but remains a major challenge.In this work,we used a facil...Rational design and synthesis of non-precious-metal catalyst plays an important role in improving the activity and stability for oxygen reduction reaction(ORR)but remains a major challenge.In this work,we used a facile approach to synthesize iron nanoparticles encapsulated in nitrogen-doped porous carbon materials(Fe@N-C)from functionalized metal-organic frameworks(MOFs,MET-6).Embedding Fe nanoparticles into the carbon skeleton increases the graphitization degree and the proportion of graphitic N as well as promotes the formation of mesopores in the catalyst.The Fe@N-C-30 catalyst showed the excellent ORR activity in alkaline solutions(E^(0)=0.97 V vs.RHE,E1/2=0.89 V vs.RHE).Moreover,the Fe@N-C-30 catalyst exhibited better methanol resistance and long-term stability when compared to commercial Pt/C.The superior ORR performance could be attributed to the combination of high electrochemical surface area,relative high portion of graphitic-N,unique porous structures and the synergistic effect between the encapsulated Fe particles and the N-doped carbon layer.This work provides a promising method to construct efficient non-precious-metal ORR catalyst through MOFs.展开更多
Lithium-sulfur(Li-S)batteries have been considered as the next generation high energy storage devices.However,its commercialization has been hindered by several issues,especially the dissolution and shuttle of the sol...Lithium-sulfur(Li-S)batteries have been considered as the next generation high energy storage devices.However,its commercialization has been hindered by several issues,especially the dissolution and shuttle of the soluble lithium polysulfides(LiPSs)as well as the slow reaction kinetics of LiPSs which may make shuttling effect even worse.Herein,we report a strategy to address this issue by in-situ transformation of Co−N_(x) coordinations in cobalt polyphthalocyanine(CoPPc)into Co nanoparticles(Co NPs)embedded in carbon matrix and mono-dispersed on graphene flakes.The Co NPs can provide rich binding and catalytic sites,while graphene flakes act as ideally LiPSs transportation and electron conducting platform.With a remarkable enhanced reaction kinetics of LiPSs via these merits,the sulfur host with a sulfur content up to 70 wt%shows a high initial capacity of 1048 mA∙h/g at 0.2C,good rate capability up to 399 mA·h/g at 2C.展开更多
The main goal of this work is to explore the possibility of using Au-modified hydroxyapatite(HA) as a potential sensor material. Tube-like HA structure was fabricated with the aid of a Nafion N-117 cation exchange mem...The main goal of this work is to explore the possibility of using Au-modified hydroxyapatite(HA) as a potential sensor material. Tube-like HA structure was fabricated with the aid of a Nafion N-117 cation exchange membrane and gold(Au) nanoparticles were added by a hydrothermal method. The morphology, structure and composition were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), and X-ray photoelectron spectroscopy(XPS). The gas sensing properties were also investigated. Results show that Au nanoparticles are dispersed into the HA powder, which is tube-like, with rough inner and outer surfaces. Compared with pure HA, Au-modified HA exhibits improved sensing properties for NH_3. 5%(mass fraction) Au-modified HA shows the highest response with relatively short response/recovery time. The response is up to 79.2% when the corresponding sensor is exposed to 200×10^(-6) NH_3 at room temperature, and the response time and recovery time are 20 s and 25 s, respectively. For lower concentration, like 50×10^(-6), the response is still up to 70.8%. Good selectivity and repeatability are also observed. The sensing mechanism of high response and selectivity for NH_3 gas was also discussed. These results suggest that Au-HA composite is a promising material for NH_3 sensors operating at room temperature.展开更多
The fluidization behavior of SiO2, ZnO and TiO2 non-magnetic nanoparticles was investigated in a magnetically fluidized bed （MFB） by adding coarse magnets. The effects of both the amount of coarse magnets and the ma...The fluidization behavior of SiO2, ZnO and TiO2 non-magnetic nanoparticles was investigated in a magnetically fluidized bed （MFB） by adding coarse magnets. The effects of both the amount of coarse magnets and the magnetic field intensity on the fluidization quality of these nanoparticles were investigated. The results show that the coarse magnets added to the bed lead to a reduction in the size of the aggregates formed naturally by the primary nanopartieles. As the macroscopic performances of improved fluidization quality, the bed expansion ratio increases whilst the minimum fluidization velocity decreases with increasing the magnetic field intensity, but for TiO2 nanoparticles there exists a suitable magnetic field intensity of 0.059 6 T. The optimal amounts of coarse magnets for SiO2, ZnO and TiO2 non-magnetic nanoparticles are 40%, 50% and 60% （mass fraction）, respectively. The bed expansion results analyzed by the Richardson-Zaki scaling law show that the exponents depend on both the amount of coarse magnets and the magnetic field intensity.展开更多
Ni nanoparticles plating was prepared in reverse microemulsion. The deposition was carried out through the Brownian motion of water pools in the reverse microemulsion and the adsorption of water pools on the electrode...Ni nanoparticles plating was prepared in reverse microemulsion. The deposition was carried out through the Brownian motion of water pools in the reverse microemulsion and the adsorption of water pools on the electrode surface. Effects of electrolytic parameters on the size of Ni particles were studied. The performances of hydrogen evolution and hydrogen storage of the Ni nanoparticles plating electrode were also investigated. The results indicate that the size of Ni nanoparticles decreases with the increase of Ni2+ concentration and the decrease of current density. The electrochemical activity of Ni nanoparticles plating electrode is much higher than that of bulk Ni electrode.展开更多
Stable and monodispersed silver nanoparticles were produced through a mild,convenient,one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer.The surface plasma...Stable and monodispersed silver nanoparticles were produced through a mild,convenient,one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer.The surface plasma band transition was monitored along with time in the reaction mixture for three sets of experiments by ultraviolet-visible spectroscopy.Analysis of the data with the Avrami equation yielded n exponent with values between 0.5 and 1.5,demonstrating three-dimensional heterogeneous nucleation and diffusion-controlled growth,accompanied by soft impingement effect.XRD and TEM analyses show a softly agglomerated polycrystalline state and a nearly spherical morphology (<50 nm) of nanoparticles.The FT-IR result indicates that the PAA molecular structure could be hardly influenced by the formation of nanoparticles.展开更多
The synthesis of high purity intermetallic FeAI nanoparticles using the flow-levitation （FL） method was reported. Iron and aluminium droplets were levitated stably at about 2 230℃. The morphology, clystal structure...The synthesis of high purity intermetallic FeAI nanoparticles using the flow-levitation （FL） method was reported. Iron and aluminium droplets were levitated stably at about 2 230℃. The morphology, clystal structure and chemical composition of FeAI nanoparticles were investigated by transmission electron microscopy （TEM）, high-resolution TEM, X-ray diffraction and energy dispersive spectrometry. The results show that the average particle size of these nanoparticles is about 34.5 nm. Measurements of the d-spacing from X-ray diffraction and electron diffraction studies confirm that the intermetallic nanoparticles have the same crystal structure （B2） as the bulk FeA1. A thin oxidation coating is formed around the particles when being exposed to air. Based on the XPS measurements, the surface coating of the FeAI nanoparticles is composed of Fe2O3 and FeAl2O4. Besides, hysteresis curve reveals that saturation magnetization （Ms） of FeA1 is 1.66 A/m2, and the coercivity is about 1.214×10^3 A/re.展开更多
Highly pure active γ-Al2O3 nanoparticles were synthesized from aluminum nitrate and ammonium carbonate with a little surfactant by chemical precipitation method. The factors affecting the synthesis process were studi...Highly pure active γ-Al2O3 nanoparticles were synthesized from aluminum nitrate and ammonium carbonate with a little surfactant by chemical precipitation method. The factors affecting the synthesis process were studied. The properties of γ-Al2O3 nanoparticles were characterized by DTA, XRD, BET, TEM, laser granularity analysis and impurity content analysis. The results show that the amorphous precursor AI（OH）3 sols are produced by using 0.1 mol/L Al（NO3）3·9H2O and 0.16 mol/L （NH4）2CO3·H2O reaction solutions, according to the volume ratio 1.33, adding 0.024%（volume fraction） surfactant PEG600, and reacting at 40℃, 1000 r/min stirring rate for 15min. Then, after stabilizing for 24 h, the precursors were extracted and filtrated by vacuum, washed thoroughly with deionized water and dehydrated ethanol, dried in vacuum at 80℃ for 8h, final calcined at 800℃ for 1h in the air, and high purity active γ-Al2O3 nanoparticles can be prepared with cubic in crystal system, OH^7-FD3M in space group, about 9 nm in crystal grain size, about 20 nm in particle size and uniform size distribution, 131.35 m^2/g in BET specific surface area, 7 - 11 nm in pore diameter, and not lower than 99.93% in purity.展开更多
OBJECTIVE Many drug candidates identified from natural products are poorly water-soluble.The surfactants used to disperse the hydrophobic anticancer drugs in water may cause a serious of acute hypersensitivity reactio...OBJECTIVE Many drug candidates identified from natural products are poorly water-soluble.The surfactants used to disperse the hydrophobic anticancer drugs in water may cause a serious of acute hypersensitivity reactions.Nanotechnology provides an alternative strategy for delivery of anticancer drugs.In the present study,different inorganic nanoparticles are utilized as hydrophobic anticancer drug carriers.METHODS Different inorganic superparamagnetic iron oxide,platinum and gold nanoparticles were synthesized.The hydrophobic anticancer drugs such as curcumin,gambogic acid and doxorubicin(DOX)base were loaded into the porous area or onto the surface of the nanoparticles.Cellular uptake and biocompatibility of nanoparticles were studied in human glioblastoma U-87 MG cells.The anticancer effect of drug loaded nanoparticles was compared with that of free drugs.Photothermal conversion of platinum and gold nanoparticles was studied by irradiation of nanoparticles with a near-infrared laser.RESULTS The synthesized nanoparticles are readily internalized by U-87 MG cells,and the internalized nanoparticles are mainly localized in endosomes/lysosomes in cells.The nanoparticle-based drug carrier provides the aqueous dispersions of the hydrophobic drugs.In endosomes/lysosomes mimicking buffers with a pH of 4.5-5.5,pH-dependent drug release was observed from drug loaded nanoparticles.The intracellular drug content and cytotoxicity are significantly higher for drug loaded nanoparticles than free drug.Photothermal treatment has a synergistic effect on drug′s anticancer activity.CONCLUSION These results suggested inorganic nanoparticles is a promising intracellular carrier for hydrophobic anticancer drugs.展开更多
A light and temperature dual responsive copolymer,poly(7-(4-vinylbenzy-loxyl)-4-methylcoumarin-co-N vinyl caprolactam-co-tri(ethylene glycol)methyl ether methacrylate)(PVNM),was grafted on the surface of dopamine base...A light and temperature dual responsive copolymer,poly(7-(4-vinylbenzy-loxyl)-4-methylcoumarin-co-N vinyl caprolactam-co-tri(ethylene glycol)methyl ether methacrylate)(PVNM),was grafted on the surface of dopamine based mesoporous silica nanoparticles(MSNs).The resulting polymer brush,MSNs-g-PVNM,was characterized by FT-IR,TEM,TGA and XPS.The dual responsive behaviors of MSNs-g-PVNM were systematically studied.With imidacloprid as the model guest pesticide,the loading percentage and loading efficiency of the polymer brush were determined as 9.2%and 40.6%,respectively.The release efficiency of imidacloprid in MSNs-g-PVNM was the lowest value of 5.4%at 20℃ and 365 nm,and it reached the highest value of 52.4%at 50℃ and 254 nm.The loss percentage of imidacloprid on the leaves contained imidacloprid-loaded MSNs-g-PVNM(8.4%)was much less than that contained only imidacloprid(25.2%)after three rinses.It was confirmed that the release process of imidacloprid was well regulated through changing external conditions such as light and temperature.展开更多
Gold nanoparticles(GNPs)have been extensively used in nanomedicine and neuroscience owing to their biological inertness,peculiar opto-electronic and physico-chemical features.However,the effect of GNPs shape on the ne...Gold nanoparticles(GNPs)have been extensively used in nanomedicine and neuroscience owing to their biological inertness,peculiar opto-electronic and physico-chemical features.However,the effect of GNPs shape on the neurophysiological properties of single neuron is still unclear.To tackle this issue,different shape GNPs(nanosphere,nanotriakisoctahedron and nanoflower)were synthesized to investigate the effect of GNPs on the voltage-dependent sodium channel and the action potential(AP)of hippocampal CA1 neurons in mice.The results indicated that GNPs inhibited the amplitudes of voltage-gated sodium current(I_(Na))and led to a hyperpolarizing shift in the voltage-dependence curve of both activation and inactivation of I_(Na).GNPs also increased neuronal excitability and altered some properties of AP.Moreover,most alterations in AP properties were observed in nanoflower GNPs treated CA1 neurons,suggesting that the neurotoxicity of gold nanoparticles is surface roughness-dependent.These results may provide a valuable direction in the clinical application of GNPs.展开更多
A silver nanoparticle(Ag NP) with good monodispersity was produced by a convenient method for reducing of Ag NO3 with N, N-dimethylacetamide in the presence of polyvinyl pyrrolidone(PVP) as the surface modification ag...A silver nanoparticle(Ag NP) with good monodispersity was produced by a convenient method for reducing of Ag NO3 with N, N-dimethylacetamide in the presence of polyvinyl pyrrolidone(PVP) as the surface modification agent. The shape and size of the Ag NP with reaction time were taken as variables. The surface plasmon band transition was monitored with reaction mixture time at different temperatures. The Ag NP crystallinity increases with the reaction time, and the reduction efficiency is very low when Ag NP solution is dealt at room temperature even after two days, while it is greatly improved at 160 °C only for 25 min. Ag NP modified by the as-synthesized PVP has a face-centered cubic crystalline structure, in which Ag NP could develop into a spherical morphology with a very narrow size distribution of 2-11 nm. The preparation provides a new reducing agent to form Ag NP with simpler operation and shorter time.展开更多
文摘A gold catalyst of Au/pyrenyl‑graphdiyne(Pyr‑GDY)was prepared by anchoring small size of gold nanoparticles(Au NPs)on the surface of Pyr‑GDY for electrocatalytic nitrogen reduction reaction(eNRR),in which Au NPs with a size of approximately 3.69 nm was evenly distributed on spongy‑like porous Pyr‑GDY.The catalyst exhibited a good electrocatalytic activity for N_(2)reduction in a nitrogen‑saturated electrolyte,with an ammonia yield of 32.1μg·h^(-1)·mg_(cat)^(-1)at-0.3 V(vs RHE),3.5 times higher than that of Au/C(Au NPs anchored on carbon black).In addition,Au/Pyr‑GDY showed a Faraday efficiency(FE)of 26.9%for eNRR,and a good catalysis durability for over 22 h.
文摘OBJECTIVE To review the application of nanoparticles modified with angiopep-2,providing theoretical guidance for the diagnosis and treatment of glioma. METHODS According to domestic and foreign research reports of nanoparticles modified with angiopep-2 in recent years,the application in the diagnosis and treatment of glioma was summarized and analyzed. RESULTS Angiopep-2 can be modified to the surface of nanoparticles loaded with imaging agents or chemotherapeutic agents,which can significantly improve the imaging effect of glioma and achieve targeted drug delivery. CONCLUSION Angiopep-2 exhibits a high brain penetration capability in blood brain barrier and in glioma cells. The nanoparticles modified with angiopep-2 can delivery various imaging agents and chemotherapeutic agents to glioma cells,the dual-targeting delivery systems can provide theoretical guidance for the diagnosis and treatment of glioma.
文摘Cotton production substantiated a crucial part in the escalating economic development of many countries.To realize the increasing global demand for cotton,the emphasis should be laid on to improve cotton fiber growth and production.The bioengineered transgenic cotton proved expedient in resolving inadequacies of conventional cotton,but still required improvements to encounter heightened demand of textile industries.One possible solution pertaining to this has been provided by nanoscience in the form of metal or metal oxide nanoparticles.These metal oxide nanoparticles have easy access to the various parts of cotton plants through its transportation system,and thus significantly influence several parameters relative to the growth and production of cotton fiber.This review summarizes the distribution and accumulation of metal oxide nanoparticles in cotton plant and its impact on different plant growth-promoting factors,which resulted in the improved cotton yields.
文摘The catalytic proficiency of three MONs for AP thermal decomposition was studied in this work.A chemical co-precipitation method was used for synthesis of MONs(CuZnO,CoZnO,and NiZnO)and their characterization carried out by utilizing XRD,FTIR,and SEM.The TGA/DSC technique was employed for the investigation of the catalytic proficiency of MONs on the AP.The DSC data were used for measuring activation energy of catalyzed AP by using Ozawa,Kissinger,and Starink method.The MONs were much sensitive for AP decomposition,and the performance of AP decomposition was further improved.Among all the MONs,the CuZnO exhibits higher catalytic action than others and decomposition temperature of AP is descending around 117℃ by CuZnO.The reduction in the activation energy was noticed after the incorporation of MONs in AP.
基金Project(17ZYPTJC00050)supported by Science and Technology Committee of Tianjin,ChinaProject(2017YFC1600803)supported by the Ministry of Science and Technology of China
文摘A novel molecularly imprinted polymer (MIP) based on upconversion nanoparticles (UCNPs) was successfully synthesized for determination of Ochratoxin A (OTA). The MIP was developed on the silica-coated UCNPs using N-(1-hydroxy-2-naphthoyl amido)-(L)-phenylalanine (HNA-Phe) as the alternative template. The final composite combined the advantages of the high selectivity of MIP with the high fluorescence intensity of UCNPs which was selective and sensitive to OTA. Under the optimal condition, the fluorescence intensity of UCNPs@SiO2@MIP decreases linearly when the concentration of OTA increases from 0.05 to 1.0 mg/L. The detection limit of OTA with the method was 0.031 mg/L. At three spiked concentration levels (50, 100 and 200 μg/kg), the recovery ranges of OTA in corn, rice and feed are 88.0%–91.6%, 80.2%–91.6% and 89.2%–90.4%, respectively.
文摘Superalloys are grouped as hard-to-cut materials with relatively poor machinability.Tool wear is considered one of the main machinability attributes in machining superalloys.Although numerous works have been reported on factors governing tool life in machining superalloys,no study was found on the effect of nanoparticles stability on nanofluid performance and consequently resulted tool wear morphologies.In the present work,the nanoparticles were reinforced by means of improving the stability of the base fluid.To that accomplished,the surface active agent (surfactant) was added to the base cutting fluid as a reinforcing element.The effects of new lubricant on the tool wear morphology of A286 works parts were assessed.
基金Projects(31201074,81371013) supported by the National Natural Science Foundation of ChinaProject(2011105102016) supported by the Key Program of Medical Health of Dongguan City,Guangdong Province,ChinaProject(2011108102026) supported by Dongguan Universities Program,China
文摘Folic acid conjugated chitosan was prepared by cross-linking reaction with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride(EDC), and then used as a template to prepare folic acid-chitosan(FA-CS) conjugated nanoparticles and load mitoxantrone nanoparticles(FA-CSNP/MTX). Drug dissolution testing, CCK-8 method, and confocal microscopy were used to detect their controlled-release capability in different situations and the specific uptake by HONE1 cells. The experimental results show that the nanoparticles have uniform size distribution of 48-58 nm. The highest encapsulation rate of the particles on mitoxantrone hydrochloride(MTX) is(77.5±1.9)%, and the drug loading efficiency is(18.4±0.4)%. The sustained release effect, cell growth inhibition activity and targeting effect of the FA-CS/MTX nanoparticles are good in artificial gastric fluid and intestinal fluid. It is demonstrated that the FA-CSNP system is a potentially useful system for the targeted delivery of anticancer drug MTX.
基金Project(20070410304) supported by Postdoctoral Foundation of ChinaProject(07JJ3105) supported by Hunan Provincial Natural Science Foundation of China
文摘Properties of hydroxyapatite （HA, Ca10（PO4）6（OH）2）, including bioactivity, biocompatibility, solubility and adsorption could be tailored over wide ranges by the control of particle composition, particle size and morphology. In order to satisfy various applications, well-crystallized pure HA nanoparticles were synthesized at moderate temperatures by hydrotherrnal synthesis, and HA nanoparticles with different lengths were obtained by adding organic additives. X-ray diffractometry （XRD） and Fourier transform infrared （FTIR） spectrometry were used to characterize these nanoparticles, and the morphologies of the HA particles were observed by transmission electron microscopy （TEM）. The results demonstrate that shorter rod-like HA particles can be prepared by adding cetyltrimethylammonium bromide （CTAB）, as the additive of CTAB can block the HA crystal growth along with c-axis. And whisker HA particles are obtained by adding ethylenediamine tetraacetic acid （EDTA）, since EDTA may have effect on the dissolution-repreeipitation process of HA.
基金supported by the National Natural Science Foundation of China(Grants 22002121,22172121)the National Undergraduate Training Program for Innovation and Entrepreneurship(Grant S202210656087).
文摘Rational design and synthesis of non-precious-metal catalyst plays an important role in improving the activity and stability for oxygen reduction reaction(ORR)but remains a major challenge.In this work,we used a facile approach to synthesize iron nanoparticles encapsulated in nitrogen-doped porous carbon materials(Fe@N-C)from functionalized metal-organic frameworks(MOFs,MET-6).Embedding Fe nanoparticles into the carbon skeleton increases the graphitization degree and the proportion of graphitic N as well as promotes the formation of mesopores in the catalyst.The Fe@N-C-30 catalyst showed the excellent ORR activity in alkaline solutions(E^(0)=0.97 V vs.RHE,E1/2=0.89 V vs.RHE).Moreover,the Fe@N-C-30 catalyst exhibited better methanol resistance and long-term stability when compared to commercial Pt/C.The superior ORR performance could be attributed to the combination of high electrochemical surface area,relative high portion of graphitic-N,unique porous structures and the synergistic effect between the encapsulated Fe particles and the N-doped carbon layer.This work provides a promising method to construct efficient non-precious-metal ORR catalyst through MOFs.
基金Project(21905220) supported by the National Natural Science Foundation of ChinaProject(BK20201190) supported by the Jiangsu Provincial Department of Science and Technology,China+2 种基金Projects(2018ZDXM-GY-135,2021JLM-36) supported by the Key Research and Development Plan of Shaanxi Province,ChinaProject(HG6J003) supported by the Fundamental Research Funds for “Young Talent Support Plan” of Xi’ an Jiaotong University,ChinaProject supported by the “1000-Plan program” of Shaanxi Province,China。
文摘Lithium-sulfur(Li-S)batteries have been considered as the next generation high energy storage devices.However,its commercialization has been hindered by several issues,especially the dissolution and shuttle of the soluble lithium polysulfides(LiPSs)as well as the slow reaction kinetics of LiPSs which may make shuttling effect even worse.Herein,we report a strategy to address this issue by in-situ transformation of Co−N_(x) coordinations in cobalt polyphthalocyanine(CoPPc)into Co nanoparticles(Co NPs)embedded in carbon matrix and mono-dispersed on graphene flakes.The Co NPs can provide rich binding and catalytic sites,while graphene flakes act as ideally LiPSs transportation and electron conducting platform.With a remarkable enhanced reaction kinetics of LiPSs via these merits,the sulfur host with a sulfur content up to 70 wt%shows a high initial capacity of 1048 mA∙h/g at 0.2C,good rate capability up to 399 mA·h/g at 2C.
基金Project(51272289) supported by the National Natural Science Foundation of China
文摘The main goal of this work is to explore the possibility of using Au-modified hydroxyapatite(HA) as a potential sensor material. Tube-like HA structure was fabricated with the aid of a Nafion N-117 cation exchange membrane and gold(Au) nanoparticles were added by a hydrothermal method. The morphology, structure and composition were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), and X-ray photoelectron spectroscopy(XPS). The gas sensing properties were also investigated. Results show that Au nanoparticles are dispersed into the HA powder, which is tube-like, with rough inner and outer surfaces. Compared with pure HA, Au-modified HA exhibits improved sensing properties for NH_3. 5%(mass fraction) Au-modified HA shows the highest response with relatively short response/recovery time. The response is up to 79.2% when the corresponding sensor is exposed to 200×10^(-6) NH_3 at room temperature, and the response time and recovery time are 20 s and 25 s, respectively. For lower concentration, like 50×10^(-6), the response is still up to 70.8%. Good selectivity and repeatability are also observed. The sensing mechanism of high response and selectivity for NH_3 gas was also discussed. These results suggest that Au-HA composite is a promising material for NH_3 sensors operating at room temperature.
基金Project(20776163) supported by the National Natural Science Foundation of ChinaProject(20070533121) supported by the PhD Programs Foundation of Ministry of Education of ChinaProject supported by the NSFC-JSPS Cooperation Program
文摘The fluidization behavior of SiO2, ZnO and TiO2 non-magnetic nanoparticles was investigated in a magnetically fluidized bed （MFB） by adding coarse magnets. The effects of both the amount of coarse magnets and the magnetic field intensity on the fluidization quality of these nanoparticles were investigated. The results show that the coarse magnets added to the bed lead to a reduction in the size of the aggregates formed naturally by the primary nanopartieles. As the macroscopic performances of improved fluidization quality, the bed expansion ratio increases whilst the minimum fluidization velocity decreases with increasing the magnetic field intensity, but for TiO2 nanoparticles there exists a suitable magnetic field intensity of 0.059 6 T. The optimal amounts of coarse magnets for SiO2, ZnO and TiO2 non-magnetic nanoparticles are 40%, 50% and 60% （mass fraction）, respectively. The bed expansion results analyzed by the Richardson-Zaki scaling law show that the exponents depend on both the amount of coarse magnets and the magnetic field intensity.
基金Projects(20673036,J0830415) supported by the National Natural Science Foundation of ChinaProject(09JJ3025) supported by Hunan Provincial Natural Science Foundation of ChinaProject(09GK3173) supported by the Planned Science and Technology Project of Hunan Province,China
文摘Ni nanoparticles plating was prepared in reverse microemulsion. The deposition was carried out through the Brownian motion of water pools in the reverse microemulsion and the adsorption of water pools on the electrode surface. Effects of electrolytic parameters on the size of Ni particles were studied. The performances of hydrogen evolution and hydrogen storage of the Ni nanoparticles plating electrode were also investigated. The results indicate that the size of Ni nanoparticles decreases with the increase of Ni2+ concentration and the decrease of current density. The electrochemical activity of Ni nanoparticles plating electrode is much higher than that of bulk Ni electrode.
基金Project(10JJ5057)supported by the Hunan Provincial Natural Science Foundation of China
文摘Stable and monodispersed silver nanoparticles were produced through a mild,convenient,one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer.The surface plasma band transition was monitored along with time in the reaction mixture for three sets of experiments by ultraviolet-visible spectroscopy.Analysis of the data with the Avrami equation yielded n exponent with values between 0.5 and 1.5,demonstrating three-dimensional heterogeneous nucleation and diffusion-controlled growth,accompanied by soft impingement effect.XRD and TEM analyses show a softly agglomerated polycrystalline state and a nearly spherical morphology (<50 nm) of nanoparticles.The FT-IR result indicates that the PAA molecular structure could be hardly influenced by the formation of nanoparticles.
基金Project(10804101) supported by the National Natural Science Foundation of China
文摘The synthesis of high purity intermetallic FeAI nanoparticles using the flow-levitation （FL） method was reported. Iron and aluminium droplets were levitated stably at about 2 230℃. The morphology, clystal structure and chemical composition of FeAI nanoparticles were investigated by transmission electron microscopy （TEM）, high-resolution TEM, X-ray diffraction and energy dispersive spectrometry. The results show that the average particle size of these nanoparticles is about 34.5 nm. Measurements of the d-spacing from X-ray diffraction and electron diffraction studies confirm that the intermetallic nanoparticles have the same crystal structure （B2） as the bulk FeA1. A thin oxidation coating is formed around the particles when being exposed to air. Based on the XPS measurements, the surface coating of the FeAI nanoparticles is composed of Fe2O3 and FeAl2O4. Besides, hysteresis curve reveals that saturation magnetization （Ms） of FeA1 is 1.66 A/m2, and the coercivity is about 1.214×10^3 A/re.
文摘Highly pure active γ-Al2O3 nanoparticles were synthesized from aluminum nitrate and ammonium carbonate with a little surfactant by chemical precipitation method. The factors affecting the synthesis process were studied. The properties of γ-Al2O3 nanoparticles were characterized by DTA, XRD, BET, TEM, laser granularity analysis and impurity content analysis. The results show that the amorphous precursor AI（OH）3 sols are produced by using 0.1 mol/L Al（NO3）3·9H2O and 0.16 mol/L （NH4）2CO3·H2O reaction solutions, according to the volume ratio 1.33, adding 0.024%（volume fraction） surfactant PEG600, and reacting at 40℃, 1000 r/min stirring rate for 15min. Then, after stabilizing for 24 h, the precursors were extracted and filtrated by vacuum, washed thoroughly with deionized water and dehydrated ethanol, dried in vacuum at 80℃ for 8h, final calcined at 800℃ for 1h in the air, and high purity active γ-Al2O3 nanoparticles can be prepared with cubic in crystal system, OH^7-FD3M in space group, about 9 nm in crystal grain size, about 20 nm in particle size and uniform size distribution, 131.35 m^2/g in BET specific surface area, 7 - 11 nm in pore diameter, and not lower than 99.93% in purity.
基金The project supported by Macao Science and Technology Development Fund(014/2014/A1)
文摘OBJECTIVE Many drug candidates identified from natural products are poorly water-soluble.The surfactants used to disperse the hydrophobic anticancer drugs in water may cause a serious of acute hypersensitivity reactions.Nanotechnology provides an alternative strategy for delivery of anticancer drugs.In the present study,different inorganic nanoparticles are utilized as hydrophobic anticancer drug carriers.METHODS Different inorganic superparamagnetic iron oxide,platinum and gold nanoparticles were synthesized.The hydrophobic anticancer drugs such as curcumin,gambogic acid and doxorubicin(DOX)base were loaded into the porous area or onto the surface of the nanoparticles.Cellular uptake and biocompatibility of nanoparticles were studied in human glioblastoma U-87 MG cells.The anticancer effect of drug loaded nanoparticles was compared with that of free drugs.Photothermal conversion of platinum and gold nanoparticles was studied by irradiation of nanoparticles with a near-infrared laser.RESULTS The synthesized nanoparticles are readily internalized by U-87 MG cells,and the internalized nanoparticles are mainly localized in endosomes/lysosomes in cells.The nanoparticle-based drug carrier provides the aqueous dispersions of the hydrophobic drugs.In endosomes/lysosomes mimicking buffers with a pH of 4.5-5.5,pH-dependent drug release was observed from drug loaded nanoparticles.The intracellular drug content and cytotoxicity are significantly higher for drug loaded nanoparticles than free drug.Photothermal treatment has a synergistic effect on drug′s anticancer activity.CONCLUSION These results suggested inorganic nanoparticles is a promising intracellular carrier for hydrophobic anticancer drugs.
基金Project(21376271)supported by the National Natural Science Foundation of ChinaProject(2016TP1007)supported by the Hunan Provincial Science and Technology Plan Project,ChinaProjects(201810533078,S2020105330395)supported by the Undergraduates Innovative Training Foundation of Central South University,China。
文摘A light and temperature dual responsive copolymer,poly(7-(4-vinylbenzy-loxyl)-4-methylcoumarin-co-N vinyl caprolactam-co-tri(ethylene glycol)methyl ether methacrylate)(PVNM),was grafted on the surface of dopamine based mesoporous silica nanoparticles(MSNs).The resulting polymer brush,MSNs-g-PVNM,was characterized by FT-IR,TEM,TGA and XPS.The dual responsive behaviors of MSNs-g-PVNM were systematically studied.With imidacloprid as the model guest pesticide,the loading percentage and loading efficiency of the polymer brush were determined as 9.2%and 40.6%,respectively.The release efficiency of imidacloprid in MSNs-g-PVNM was the lowest value of 5.4%at 20℃ and 365 nm,and it reached the highest value of 52.4%at 50℃ and 254 nm.The loss percentage of imidacloprid on the leaves contained imidacloprid-loaded MSNs-g-PVNM(8.4%)was much less than that contained only imidacloprid(25.2%)after three rinses.It was confirmed that the release process of imidacloprid was well regulated through changing external conditions such as light and temperature.
基金Project(LY19C090004)supported by the Natural Science Foundation of Zhejiang Province,ChinaProjects(BK20200710,BK2018077)supported by the Natural Science Foundation of Jiangsu Province,China+1 种基金Project(NHKY-2019-19)supported by the Nanjing Polytechnic Institute Start Fund,ChinaProject(202012920026Y)supported by the Innovation and Entrepreneurship Training Program of Jiangsu Province College Students,China。
文摘Gold nanoparticles(GNPs)have been extensively used in nanomedicine and neuroscience owing to their biological inertness,peculiar opto-electronic and physico-chemical features.However,the effect of GNPs shape on the neurophysiological properties of single neuron is still unclear.To tackle this issue,different shape GNPs(nanosphere,nanotriakisoctahedron and nanoflower)were synthesized to investigate the effect of GNPs on the voltage-dependent sodium channel and the action potential(AP)of hippocampal CA1 neurons in mice.The results indicated that GNPs inhibited the amplitudes of voltage-gated sodium current(I_(Na))and led to a hyperpolarizing shift in the voltage-dependence curve of both activation and inactivation of I_(Na).GNPs also increased neuronal excitability and altered some properties of AP.Moreover,most alterations in AP properties were observed in nanoflower GNPs treated CA1 neurons,suggesting that the neurotoxicity of gold nanoparticles is surface roughness-dependent.These results may provide a valuable direction in the clinical application of GNPs.
基金Project(126223)supported by Postdoctoral Fund of Central South University,ChinaProject(13JJ4102)supported by the Natural Science Foundation of Hunan Province,ChinaProject(14A025)supported by the Research Foundation of Education Bureau of Hunan Province,China
文摘A silver nanoparticle(Ag NP) with good monodispersity was produced by a convenient method for reducing of Ag NO3 with N, N-dimethylacetamide in the presence of polyvinyl pyrrolidone(PVP) as the surface modification agent. The shape and size of the Ag NP with reaction time were taken as variables. The surface plasmon band transition was monitored with reaction mixture time at different temperatures. The Ag NP crystallinity increases with the reaction time, and the reduction efficiency is very low when Ag NP solution is dealt at room temperature even after two days, while it is greatly improved at 160 °C only for 25 min. Ag NP modified by the as-synthesized PVP has a face-centered cubic crystalline structure, in which Ag NP could develop into a spherical morphology with a very narrow size distribution of 2-11 nm. The preparation provides a new reducing agent to form Ag NP with simpler operation and shorter time.
