The nano-MoS2 particles were adopted to substitute for the extreme-pressure and anti-wear additives to the rolling fluid for steel strips.An optimal formulation and technical process for adding nano-MoS2 particles to ...The nano-MoS2 particles were adopted to substitute for the extreme-pressure and anti-wear additives to the rolling fluid for steel strips.An optimal formulation and technical process for adding nano-MoS2 particles to the rolling fluid were obtained through orthogonal experiments with three factors at three levels.The tests have led to the following conclusions:(a) the nanoparticles should be added to a base oil with high saponification value;(b) the concentration of nanoparticles in rolling fluid should be equal to 0.6%;and (c) when the reaction time needed for surfactants (oleic acid,for example) to modify the nanoparticles was 40 min,the rolling fluid could have the best tribological properties.The lubricity of rolling fluid was verified by using a 4-high cold rolling test mill which showed that the rolling fluid with nano-MoS2 particles had the excellent lubricant performance to improve the surface quality of the steel strip remarkably.The mechanism of nano-MoS2 particles in the rolling process has been investigated by a series of characterization instruments,which have showed that,with its fullerene-like structure,the nano-MoS2 particles have self-lubricating properties and extra-low friction coefficient,and can easily form a protective film with low shear strength on the surface of friction pairs.展开更多
To better understand the nature of carbon nanotubes supported Co-Mo catalysts （Co-Mo/CNTs） for selective hydrodesulfurization （HDS） of fluid catalytic cracking （FCC） gasoline, studies are carried out using in si...To better understand the nature of carbon nanotubes supported Co-Mo catalysts （Co-Mo/CNTs） for selective hydrodesulfurization （HDS） of fluid catalytic cracking （FCC） gasoline, studies are carried out using in situ Fourier transform infrared spectroscopy （FT-IR）. The catalytic performances of Co-Mo/CNTs catalysts were evaluated with a mixture of cyclohexane, diisobutylene, cyclohexene, 1-octene （60 ： 30 ： 5 ： 5, volume ratio） and thiophene （0.5%, ratio of total weight） as model compounds to simulate FCC gasoline. The HDS experimental results suggested that the HDS activity and selectivity of Co-Mo/CNTs catalysts were affected by Co/Mo ratio; the optimal Co/Mo atomic ratio is about 0.4, and the optimum reaction temperature is 260 ℃. The in situ FT-IR studies revealed that 1-octene can be completely saturated at 200 ℃. In the FT-IR spectra of diisobutylene, the characteristic absorption peak around 3081 cm^-1 for the stretching vibration peak of =C-H bond was still clear at 320 ℃ indicating that diisobutylene is difficult to be hydrogenated. As for the thiophene, no characteristic absorption peak could be found around 3092 cm^-1 and 835 cm^-1 when the reaction temperature was raised to 280 ℃, indicating that thiophene had been completely hydrodesulfurized. On the basis of FT-IR results, it can be deduced that thiophene HDS reaction occurred mainly through direct hydrogenolysis route, whereas thiophene HDS and diisobutylene hydrogenation reaction over Co-Mo/CNTs catalysts might occur on two different kinds of active sites.展开更多
Dopamine(DA)is a vital neurotransmitter,and accurate detection of its concentration is critical for both clinical diagnos-tics and neuroscience research.Due to its electrochemical activity,DA is commonly detected usin...Dopamine(DA)is a vital neurotransmitter,and accurate detection of its concentration is critical for both clinical diagnos-tics and neuroscience research.Due to its electrochemical activity,DA is commonly detected using electrochemical methods,which are favored for their simplicity,fast response time,and suitability for in vivo analysis.In this work,a highly sensitive DA electrochemical sensor was developed using an Au@MoS_(2)composite,created by modifying molybdenum disulfide(MoS_(2))nanosheets with gold nanoparticles through HAuCl_(4) reduction,and it was aimed at enhancing DA adsorption and improving detection performance.Scanning Electron Microscopy(SEM),transmission electron microscopy(TEM),Energy Dispersive Spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS)and X-ray Diffraction(XRD)confirmed the suc-cessful synthesis of Au@MoS_(2)and the uniform distribution of gold nanoparticles across the MoS_(2)nanosheets.Then,the electrochemical characterization demonstrated that the Au@MoS_(2)/GCE exhibited distinct oxidation peaks in a 10μmol·L^(-1)DA solution,with significantly enhanced electrochemical activity compared to both unmodified GCE and pristine MoS_(2).Furthermore,differential pulse voltammetry(DPV)further revealed a strong linear relationship between DA concentration and the current response in the range of 800 nmol·L^(-1)to 10μmol·L^(-1),with a low detection limit(LOD)of 78.9 nmol·L^(-1)(S/N=3).Additionally,the sensor showed excellent selectivity against other interfering substances.Moreover,the laser-induced Au@MoS_(2)(LIAu@MoS_(2)),with its abundance of negatively charged surface defects,enabled the ultra-sensitive detection of the ultra-low concentrations of DA.In conclusion,the successfully fabricated Au@MoS_(2)based sensor offers advantages such as low cost,ease of operation,and scalability,making it a promising candidate for biosensing applications due to its enhanced DA detection capabilities.展开更多
基金supported by the "863" Program-the National High Technology Research and Development Program of China (2009AA03Z339)
文摘The nano-MoS2 particles were adopted to substitute for the extreme-pressure and anti-wear additives to the rolling fluid for steel strips.An optimal formulation and technical process for adding nano-MoS2 particles to the rolling fluid were obtained through orthogonal experiments with three factors at three levels.The tests have led to the following conclusions:(a) the nanoparticles should be added to a base oil with high saponification value;(b) the concentration of nanoparticles in rolling fluid should be equal to 0.6%;and (c) when the reaction time needed for surfactants (oleic acid,for example) to modify the nanoparticles was 40 min,the rolling fluid could have the best tribological properties.The lubricity of rolling fluid was verified by using a 4-high cold rolling test mill which showed that the rolling fluid with nano-MoS2 particles had the excellent lubricant performance to improve the surface quality of the steel strip remarkably.The mechanism of nano-MoS2 particles in the rolling process has been investigated by a series of characterization instruments,which have showed that,with its fullerene-like structure,the nano-MoS2 particles have self-lubricating properties and extra-low friction coefficient,and can easily form a protective film with low shear strength on the surface of friction pairs.
基金National Basic Research Program of China ("973"Program,No.2004CB217807)
文摘To better understand the nature of carbon nanotubes supported Co-Mo catalysts （Co-Mo/CNTs） for selective hydrodesulfurization （HDS） of fluid catalytic cracking （FCC） gasoline, studies are carried out using in situ Fourier transform infrared spectroscopy （FT-IR）. The catalytic performances of Co-Mo/CNTs catalysts were evaluated with a mixture of cyclohexane, diisobutylene, cyclohexene, 1-octene （60 ： 30 ： 5 ： 5, volume ratio） and thiophene （0.5%, ratio of total weight） as model compounds to simulate FCC gasoline. The HDS experimental results suggested that the HDS activity and selectivity of Co-Mo/CNTs catalysts were affected by Co/Mo ratio; the optimal Co/Mo atomic ratio is about 0.4, and the optimum reaction temperature is 260 ℃. The in situ FT-IR studies revealed that 1-octene can be completely saturated at 200 ℃. In the FT-IR spectra of diisobutylene, the characteristic absorption peak around 3081 cm^-1 for the stretching vibration peak of =C-H bond was still clear at 320 ℃ indicating that diisobutylene is difficult to be hydrogenated. As for the thiophene, no characteristic absorption peak could be found around 3092 cm^-1 and 835 cm^-1 when the reaction temperature was raised to 280 ℃, indicating that thiophene had been completely hydrodesulfurized. On the basis of FT-IR results, it can be deduced that thiophene HDS reaction occurred mainly through direct hydrogenolysis route, whereas thiophene HDS and diisobutylene hydrogenation reaction over Co-Mo/CNTs catalysts might occur on two different kinds of active sites.
基金supported by the Young Talent Innovation Team Support Project from Zhengzhou University(No.32213280)the scientific research program of innovation platform in State Tobacco Monopoly Administrationthe State Key Program of National Natural Science Foundation of China(Grant No.32130083).
文摘Dopamine(DA)is a vital neurotransmitter,and accurate detection of its concentration is critical for both clinical diagnos-tics and neuroscience research.Due to its electrochemical activity,DA is commonly detected using electrochemical methods,which are favored for their simplicity,fast response time,and suitability for in vivo analysis.In this work,a highly sensitive DA electrochemical sensor was developed using an Au@MoS_(2)composite,created by modifying molybdenum disulfide(MoS_(2))nanosheets with gold nanoparticles through HAuCl_(4) reduction,and it was aimed at enhancing DA adsorption and improving detection performance.Scanning Electron Microscopy(SEM),transmission electron microscopy(TEM),Energy Dispersive Spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS)and X-ray Diffraction(XRD)confirmed the suc-cessful synthesis of Au@MoS_(2)and the uniform distribution of gold nanoparticles across the MoS_(2)nanosheets.Then,the electrochemical characterization demonstrated that the Au@MoS_(2)/GCE exhibited distinct oxidation peaks in a 10μmol·L^(-1)DA solution,with significantly enhanced electrochemical activity compared to both unmodified GCE and pristine MoS_(2).Furthermore,differential pulse voltammetry(DPV)further revealed a strong linear relationship between DA concentration and the current response in the range of 800 nmol·L^(-1)to 10μmol·L^(-1),with a low detection limit(LOD)of 78.9 nmol·L^(-1)(S/N=3).Additionally,the sensor showed excellent selectivity against other interfering substances.Moreover,the laser-induced Au@MoS_(2)(LIAu@MoS_(2)),with its abundance of negatively charged surface defects,enabled the ultra-sensitive detection of the ultra-low concentrations of DA.In conclusion,the successfully fabricated Au@MoS_(2)based sensor offers advantages such as low cost,ease of operation,and scalability,making it a promising candidate for biosensing applications due to its enhanced DA detection capabilities.
