Gd202S：Eu3＋ nanoparticles were synthesized using two step process consisting of sulfuration of basic carbonates obtained by homogenous precipitation. Annealing of lanthanide nitrates at total concentration of 5x 10^...Gd202S：Eu3＋ nanoparticles were synthesized using two step process consisting of sulfuration of basic carbonates obtained by homogenous precipitation. Annealing of lanthanide nitrates at total concentration of 5x 10^-3 mol/L in a water solution containing relatively high, three molar concentration of urea ensured the optimal conditions for the reproducible preparation of uniform and small spherical particles. During sulfuration step elemental sulfur was mixed with precursor which eliminated necessity of using an auxiliary furnace and provided sulfur-reach reaction atmosphere. Such optimized protocol afforded synthesis of spherical and non-agglomerated nanoparticles with diameter smaller than 100 nm. The precursors morphology was maintained, but particles size was reduced by 15%-20% during sulfuration. The results indicated that higher emission intensity was observed for Gd202S：Eu3＋（8%） oxysulfide sample synthesized using crystalline Gd（CO3）OH precursor, than for that obtained from amorphous Gd2（OH）2（CO3）2.H20 precursor, although some further efforts to improve morphology of the former are still required.展开更多
A novel 1064 tun laser stealth absorbent of SmzO2S was prepared by flux method. The effects of different calcining temperatures and fluxes on the reflective property of Sm2O2S were investigated. The phase composition,...A novel 1064 tun laser stealth absorbent of SmzO2S was prepared by flux method. The effects of different calcining temperatures and fluxes on the reflective property of Sm2O2S were investigated. The phase composition, morphology, and reflectivity of the powders were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and ultraviolet-visible spectrophotometer （UVPC）. The results showed that pure phase of Sm202S could be obtained with Na2CO3 as flux above 950~C, and the reflectivity decreased with the calcination temperature increasing. Compared with other samarium compounds, the reflectivity at 1064 nm of Sm2O2S was the lowest. Different fluxes had great impact on the phase composition, particle morphology, and reflectivity of the products. In short, Sm2O2S was suitable as a kind of absorbent against 1064 nm laser.展开更多
Zn（O,S）（zinc oxysulfide） is an important chalcogenide material recently reported to be potentially applied as electrode buffers in thin film solar cells. Both vacuum and solution approaches have enabled the fabric...Zn（O,S）（zinc oxysulfide） is an important chalcogenide material recently reported to be potentially applied as electrode buffers in thin film solar cells. Both vacuum and solution approaches have enabled the fabrication of Zn（O,S） films. However they either require extreme conditions and high energy consumption for synthesis, or suffer from lack of controllability mainly due to the thermodynamic and kinetic distinction between Zn O and Zn S during film growth. Here we demonstrated an effective electrodeposition route to obtain high-quality Zn（O,S） thin films in a controllable manner. Importantly, tartaric acid was employed as a secondary complexing agent in the electrolyte to improve the film morphology, as well as to adjust other key properties such as composition and absorption. To elucidate the vital role that tartaric acid played, thermodynamic and kinetic processes of electrodeposition was investigated and discussed in detail. The accumulative contribution has shed light on further exploit of Zn（O,S） with tunable properties and optimization of the corresponding electrodeposition process, for the application in thin film solar cells.展开更多
Efficient and durable oxygen evolution reaction(OER)requires the electrocatalyst to bear abundant active sites,optimized electronic structure as well as robust component and mechanical stability.Herein,a bimetallic la...Efficient and durable oxygen evolution reaction(OER)requires the electrocatalyst to bear abundant active sites,optimized electronic structure as well as robust component and mechanical stability.Herein,a bimetallic lanthanum-nickel oxysulfide with rich oxygen vacancies based on the La_(2)O_(2)S prototype is fabricated as a binder-free precatalyst for alkaline OER.The combination of advanced in situ and ex situ characterizations with theoretical calculation uncovers the synergistic effect among La,Ni,O,and S species during OER,which assures the adsorption and stabilization of the oxyanion SO_(4)^(2-)onto the surface of the deeply reconstructed porous heterostructure composed of confining Ni OOH nanodomains by La(OH)_3 barrier.Such coupling,confinement,porosity and immobilization enable notable improvement in active site accessibility,phase stability,mass diffusion capability and the intrinsic Gibbs free energy of oxygen-containing intermediates.The optimized electrocatalyst delivers exceptional alkaline OER activity and durability,outperforming most of the Ni-based benchmark OER electrocatalysts.展开更多
In order to better solve the problem of electromagnetic pollution in the civil building cement,to improve the absorption capacity of magnesium oxysulfide cement based materials,and to better use sulfur oxide magnesium...In order to better solve the problem of electromagnetic pollution in the civil building cement,to improve the absorption capacity of magnesium oxysulfide cement based materials,and to better use sulfur oxide magnesium cement foamed sheet for improvement of electromagnetic industry,this paper uses the excellent microwave absorbing properties of ferrite and the modified sulfur oxide magnesium cement foam board,and discusses the microwave absorbing performance,aiming at improving the electromagnetic pollution in daily life.The effects of ferrite and silicon carbide doping on microwave absorption properties of modified magnesium oxysulfate cement were studied.At the same time,the wave absorbing properties of the corresponding samples were detected by bow method,and the causes of the corresponding phenomena were analyzed by scanning electron microscopy (SEM).The results show that the lowest reflectance of the material is-17.9 dB at 34.1 GHz and the average reflectance of the whole band is-15.9 dB under the target frequency band of 26.5-40 GHz.Under the action of external magnetic field,the absorbing particles are affected by magnetization force,magnetic dipole and resistance coupling,and play the absorbing effect in the cement base solidified completely in the electromagnetic field environment.The lowest reflectance is-17.3dB at 36.4GHz and the average reflectance is-14.3dB for the whole band.展开更多
The results of the photoelectron spectra for the oxysulfide glasses in the Li2S-B2O3 (-LiBr) spotems are discussed. The peak resolved S2p spectra show the existences of bridging and non-bridging S. The values of the b...The results of the photoelectron spectra for the oxysulfide glasses in the Li2S-B2O3 (-LiBr) spotems are discussed. The peak resolved S2p spectra show the existences of bridging and non-bridging S. The values of the binding energy of Lits indicate the chemical environmemts of Li+ ions.展开更多
Sodium dihydrogen phosphate (NaH_(2)PO_(4)) and potassium dihydrogen phosphate (KH_(2)PO_(4)) were selected as additives for magnesium oxysulfate (MOS) cement.The phase composition and the microstructure of MOS cement...Sodium dihydrogen phosphate (NaH_(2)PO_(4)) and potassium dihydrogen phosphate (KH_(2)PO_(4)) were selected as additives for magnesium oxysulfate (MOS) cement.The phase composition and the microstructure of MOS cement were characterized using X-ray diffraction (XRD),thermogravimetric analysis (TG-DSC),Flourier transform infrared spectroscopy (FT-IR),mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM).It is found that both NaH_(2)PO_(4) and KH_(2)PO_(4) lead to an increase in the compressive strength and an improvement in the volume stability of MOS cement.The XRD,MIP and SEM results show that the addition of NaH_(2)PO_(4) or KH_(2)PO_(4) does not change the phase composition of MOS cement but promotes the formation of strength phase of 5Mg(OH)_(2)·MgSO_(4)·7H_(2)O (5·1·7 phase).This phase brings a considerable improvement in the microstructure of MOS cement,which has a positive effect on the properties of MOS cement.展开更多
Magnesium oxysulfate whisker（MOSW） was produced using magnesite and sulfuric acid as raw materials by hydrothermal method and further modified by taking zinc stearate as modifier via wet chemical method.The infiuenc...Magnesium oxysulfate whisker（MOSW） was produced using magnesite and sulfuric acid as raw materials by hydrothermal method and further modified by taking zinc stearate as modifier via wet chemical method.The infiuences of the amount of modifier, slurry concentration, modification duration, modification temperature and the stirring rate on the surface modification were investigated. The effects of surface modification in functional groups, morphology and electron binding energies of surface elements of MOSW were characterized by Fourier transform infrared spectroscopy（FT-IR）, scanning electron microscopy（SEM） and X-ray photoelectron spectroscopy（XPS）. The mechanism of modification was analyzed by studying the microstructure model of the surface of MOSW, which was modified by zinc stearate. The results show that the coordination is generated by the Mg element and O in carboxylic ion of modifier, and the chemical bond could be obtained by modification. Moreover, the surface of MOSW bonds the molecules of zinc stearate, and it becomes rough. Then, the hydrophobicity of MOSW is also improved significantly. In addition, the 1s electron binding energies of Mg and O on the surface of MOSW decrease by1.2 and 0.2 eV, respectively.展开更多
Loss of drilling fluids in large porous and fractured zones inevitably up-regulates the overall cost of drilling.As a type of acid-soluble cement,magnesium oxysulfate(MOS)cement is arousing huge attention for the less...Loss of drilling fluids in large porous and fractured zones inevitably up-regulates the overall cost of drilling.As a type of acid-soluble cement,magnesium oxysulfate(MOS)cement is arousing huge attention for the less hygroscopic nature and less damaging to steel casings compared with magnesium oxychloride(MOC)cement.The present study developed MOS cement as a fast setting,high strength and acid-soluble lost circulation material to reduce the problem of losses.As suggested in this study,a higher strength of MOS cement at 70℃could be achieved by elevating M_(g)O/MgSO_(4)·7 H_(2)O molar ratio or downregulating H_(2)O/MgSO_(4)·7 H_(2)O molar ratio.Boric acid and borax could act as effective retarders.Plugging slurry based on MOS cement could effectively block the simulated porous loss zones exhibiting a diameter from 1.24 mm to 1.55 mm,as well as the fractured loss zones with a width from 2 mm to 5 mm and bearing a pressure difference up to 8 MPa.Permeability recovery test demonstrated that it facilitated future oil and gas production.The successful field application in the Junggar Basin,Xinjiang,China verified the significant plugging effect of MOS cement for severe loss problems.展开更多
The growth habit of the basic magnesium oxysulfate whisker was investigated based on the theoreticalmodelof anion coordination polyhedron growth units.It is found that typicalbasic magnesium oxysulfate whisker growth ...The growth habit of the basic magnesium oxysulfate whisker was investigated based on the theoreticalmodelof anion coordination polyhedron growth units.It is found that typicalbasic magnesium oxysulfate whisker growth is consistent with anion tetrahedralcoordination incorporation rules.The growth units of basic magnesium oxysulfate whiskers are [Mg-（OH）_4]^（2-） and HSO_4^-.[Mg-（OH）_4]^（2-） is the favorable growth unit and whisker growth is in the direction of the [Mg-（OH）_4]^（2-） combination.A plurality of [Mg-（OH）_4]^（2-） s combine and become a larger dimensionalgrowth unit in a one-dimensionaldirection.Then HSO_4^- and larger dimensionalgrowth units connect as basic magnesium sulfate whiskers,according to the structuralcharacteristics of the basic magnesium sulfate whisker,which can guide the synthesis of magnesium hydroxide whisker.展开更多
The cold isostatic press pretreatment process was adopted to prepare fine rare earth oxysulfide up-conversion phosphors with spherical shape, narrow size distribution and high luminescence efficiency. The upconversion...The cold isostatic press pretreatment process was adopted to prepare fine rare earth oxysulfide up-conversion phosphors with spherical shape, narrow size distribution and high luminescence efficiency. The upconversion optical characteristics and brightness of the blue (Y2O2SYb,Tm), green (Y2O2S: Yb,Er), red (Y2O3Yb,Er) emitter were also investigated, and a novel method was successfully developed for the brightness measurement of upconversion luminescence (UPL). It is shown that a white color can be obtained by the appropriate mixture of these primary blue, green and red emissions components. The Er3+ ions exhibit different upconversion mechanism in Y2O2S and Y2O3 host materials. The rare earth oxysulfide is an efficient upconversion matrix. The UPL brightness of Y2O2S: Yb,Er is 6.5 times higher than that of Y2O3: Yb,Er, and Y2O2S: Yb,Er shows UPL brightness of 1100 cd/m2 under 5.56 W/cm2 power density using a 980 nm laser diode.展开更多
基金Project supported by Wroclaw Research Centre EIT+within the project"The Application of Nanotechnology in Advanced Materials”-Nano Mat(POIG.01.01.02-02-002/08) co-financed by the European Regional Development Fund(Operational Programme Innovative Economy,1.1.2)
文摘Gd202S：Eu3＋ nanoparticles were synthesized using two step process consisting of sulfuration of basic carbonates obtained by homogenous precipitation. Annealing of lanthanide nitrates at total concentration of 5x 10^-3 mol/L in a water solution containing relatively high, three molar concentration of urea ensured the optimal conditions for the reproducible preparation of uniform and small spherical particles. During sulfuration step elemental sulfur was mixed with precursor which eliminated necessity of using an auxiliary furnace and provided sulfur-reach reaction atmosphere. Such optimized protocol afforded synthesis of spherical and non-agglomerated nanoparticles with diameter smaller than 100 nm. The precursors morphology was maintained, but particles size was reduced by 15%-20% during sulfuration. The results indicated that higher emission intensity was observed for Gd202S：Eu3＋（8%） oxysulfide sample synthesized using crystalline Gd（CO3）OH precursor, than for that obtained from amorphous Gd2（OH）2（CO3）2.H20 precursor, although some further efforts to improve morphology of the former are still required.
基金financially supported by the Natural Science Foundation of Jiangsu Province (No.BK2007724)Military Coordination Scientific Research Projects (No.JPPT-1486)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions (No.CXZZ110333)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘A novel 1064 tun laser stealth absorbent of SmzO2S was prepared by flux method. The effects of different calcining temperatures and fluxes on the reflective property of Sm2O2S were investigated. The phase composition, morphology, and reflectivity of the powders were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and ultraviolet-visible spectrophotometer （UVPC）. The results showed that pure phase of Sm202S could be obtained with Na2CO3 as flux above 950~C, and the reflectivity decreased with the calcination temperature increasing. Compared with other samarium compounds, the reflectivity at 1064 nm of Sm2O2S was the lowest. Different fluxes had great impact on the phase composition, particle morphology, and reflectivity of the products. In short, Sm2O2S was suitable as a kind of absorbent against 1064 nm laser.
基金funding support from the National Natural Science Foundation of China(21371016)funding support from Young Talent Thousand Program
文摘Zn（O,S）（zinc oxysulfide） is an important chalcogenide material recently reported to be potentially applied as electrode buffers in thin film solar cells. Both vacuum and solution approaches have enabled the fabrication of Zn（O,S） films. However they either require extreme conditions and high energy consumption for synthesis, or suffer from lack of controllability mainly due to the thermodynamic and kinetic distinction between Zn O and Zn S during film growth. Here we demonstrated an effective electrodeposition route to obtain high-quality Zn（O,S） thin films in a controllable manner. Importantly, tartaric acid was employed as a secondary complexing agent in the electrolyte to improve the film morphology, as well as to adjust other key properties such as composition and absorption. To elucidate the vital role that tartaric acid played, thermodynamic and kinetic processes of electrodeposition was investigated and discussed in detail. The accumulative contribution has shed light on further exploit of Zn（O,S） with tunable properties and optimization of the corresponding electrodeposition process, for the application in thin film solar cells.
基金supported by National MCF Energy R&D Program of China(2018YFE0306105)National Key R&D Program of China(2020YFA0406104,2020YFA0406101)+10 种基金Innovative Research Group Project of the National Natural Science Foundation of China(51821002)National Natural Science Foundation of China(52201269,51725204,21771132,51972216,52041202)Natural Science Foundation of Jiangsu Province(BK20210735)Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(21KJB430043)Collaborative Innovation Center of Suzhou Nano Science&Technologythe 111 ProjectSuzhou Key Laboratory of Functional Nano&Soft MaterialsJiangsu Key Laboratory for Advanced Negative Carbon Technologiesthe funding from Alexander von Humboldt(AvH)FoundationGusu leading talent plan for scientific and technological innovation and entrepreneurship(ZXL2022487)support from the German Federal Ministry of Education and Research in the framework of the project Catlab(03EW0015A/B)。
文摘Efficient and durable oxygen evolution reaction(OER)requires the electrocatalyst to bear abundant active sites,optimized electronic structure as well as robust component and mechanical stability.Herein,a bimetallic lanthanum-nickel oxysulfide with rich oxygen vacancies based on the La_(2)O_(2)S prototype is fabricated as a binder-free precatalyst for alkaline OER.The combination of advanced in situ and ex situ characterizations with theoretical calculation uncovers the synergistic effect among La,Ni,O,and S species during OER,which assures the adsorption and stabilization of the oxyanion SO_(4)^(2-)onto the surface of the deeply reconstructed porous heterostructure composed of confining Ni OOH nanodomains by La(OH)_3 barrier.Such coupling,confinement,porosity and immobilization enable notable improvement in active site accessibility,phase stability,mass diffusion capability and the intrinsic Gibbs free energy of oxygen-containing intermediates.The optimized electrocatalyst delivers exceptional alkaline OER activity and durability,outperforming most of the Ni-based benchmark OER electrocatalysts.
基金Funded by National Defense Basic Research Program Project。
文摘In order to better solve the problem of electromagnetic pollution in the civil building cement,to improve the absorption capacity of magnesium oxysulfide cement based materials,and to better use sulfur oxide magnesium cement foamed sheet for improvement of electromagnetic industry,this paper uses the excellent microwave absorbing properties of ferrite and the modified sulfur oxide magnesium cement foam board,and discusses the microwave absorbing performance,aiming at improving the electromagnetic pollution in daily life.The effects of ferrite and silicon carbide doping on microwave absorption properties of modified magnesium oxysulfate cement were studied.At the same time,the wave absorbing properties of the corresponding samples were detected by bow method,and the causes of the corresponding phenomena were analyzed by scanning electron microscopy (SEM).The results show that the lowest reflectance of the material is-17.9 dB at 34.1 GHz and the average reflectance of the whole band is-15.9 dB under the target frequency band of 26.5-40 GHz.Under the action of external magnetic field,the absorbing particles are affected by magnetization force,magnetic dipole and resistance coupling,and play the absorbing effect in the cement base solidified completely in the electromagnetic field environment.The lowest reflectance is-17.3dB at 36.4GHz and the average reflectance is-14.3dB for the whole band.
文摘The results of the photoelectron spectra for the oxysulfide glasses in the Li2S-B2O3 (-LiBr) spotems are discussed. The peak resolved S2p spectra show the existences of bridging and non-bridging S. The values of the binding energy of Lits indicate the chemical environmemts of Li+ ions.
基金Supported by the Key Research and Development and Transformation Plan of Qinghai Province-Special Project for Transforming Scientific and Technological Achievements(No.2019-NN-159)。
文摘Sodium dihydrogen phosphate (NaH_(2)PO_(4)) and potassium dihydrogen phosphate (KH_(2)PO_(4)) were selected as additives for magnesium oxysulfate (MOS) cement.The phase composition and the microstructure of MOS cement were characterized using X-ray diffraction (XRD),thermogravimetric analysis (TG-DSC),Flourier transform infrared spectroscopy (FT-IR),mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM).It is found that both NaH_(2)PO_(4) and KH_(2)PO_(4) lead to an increase in the compressive strength and an improvement in the volume stability of MOS cement.The XRD,MIP and SEM results show that the addition of NaH_(2)PO_(4) or KH_(2)PO_(4) does not change the phase composition of MOS cement but promotes the formation of strength phase of 5Mg(OH)_(2)·MgSO_(4)·7H_(2)O (5·1·7 phase).This phase brings a considerable improvement in the microstructure of MOS cement,which has a positive effect on the properties of MOS cement.
基金financially supported by the National Natural Science Foundation of China (No. 51272163)
文摘Magnesium oxysulfate whisker（MOSW） was produced using magnesite and sulfuric acid as raw materials by hydrothermal method and further modified by taking zinc stearate as modifier via wet chemical method.The infiuences of the amount of modifier, slurry concentration, modification duration, modification temperature and the stirring rate on the surface modification were investigated. The effects of surface modification in functional groups, morphology and electron binding energies of surface elements of MOSW were characterized by Fourier transform infrared spectroscopy（FT-IR）, scanning electron microscopy（SEM） and X-ray photoelectron spectroscopy（XPS）. The mechanism of modification was analyzed by studying the microstructure model of the surface of MOSW, which was modified by zinc stearate. The results show that the coordination is generated by the Mg element and O in carboxylic ion of modifier, and the chemical bond could be obtained by modification. Moreover, the surface of MOSW bonds the molecules of zinc stearate, and it becomes rough. Then, the hydrophobicity of MOSW is also improved significantly. In addition, the 1s electron binding energies of Mg and O on the surface of MOSW decrease by1.2 and 0.2 eV, respectively.
基金supported by the National Natural Science Foundation(Grant No.51874329 and Grant No.52004297 and Grant No.51991361)the National Natural Science Innovation Population of China(Grant No.51821092)+1 种基金the Strategic Cooperation Technology Projects of CNPC and CUPB(Grant No.ZLZX2020-01)Cooperation projects of CCDC and CUPB(CQ2021B-33-Z2-3)。
文摘Loss of drilling fluids in large porous and fractured zones inevitably up-regulates the overall cost of drilling.As a type of acid-soluble cement,magnesium oxysulfate(MOS)cement is arousing huge attention for the less hygroscopic nature and less damaging to steel casings compared with magnesium oxychloride(MOC)cement.The present study developed MOS cement as a fast setting,high strength and acid-soluble lost circulation material to reduce the problem of losses.As suggested in this study,a higher strength of MOS cement at 70℃could be achieved by elevating M_(g)O/MgSO_(4)·7 H_(2)O molar ratio or downregulating H_(2)O/MgSO_(4)·7 H_(2)O molar ratio.Boric acid and borax could act as effective retarders.Plugging slurry based on MOS cement could effectively block the simulated porous loss zones exhibiting a diameter from 1.24 mm to 1.55 mm,as well as the fractured loss zones with a width from 2 mm to 5 mm and bearing a pressure difference up to 8 MPa.Permeability recovery test demonstrated that it facilitated future oil and gas production.The successful field application in the Junggar Basin,Xinjiang,China verified the significant plugging effect of MOS cement for severe loss problems.
基金Funded by the National Natural Science Foundation of China(No.51272207)
文摘The growth habit of the basic magnesium oxysulfate whisker was investigated based on the theoreticalmodelof anion coordination polyhedron growth units.It is found that typicalbasic magnesium oxysulfate whisker growth is consistent with anion tetrahedralcoordination incorporation rules.The growth units of basic magnesium oxysulfate whiskers are [Mg-（OH）_4]^（2-） and HSO_4^-.[Mg-（OH）_4]^（2-） is the favorable growth unit and whisker growth is in the direction of the [Mg-（OH）_4]^（2-） combination.A plurality of [Mg-（OH）_4]^（2-） s combine and become a larger dimensionalgrowth unit in a one-dimensionaldirection.Then HSO_4^- and larger dimensionalgrowth units connect as basic magnesium sulfate whiskers,according to the structuralcharacteristics of the basic magnesium sulfate whisker,which can guide the synthesis of magnesium hydroxide whisker.
基金Supported by the National Natural Science Foundation of China (Grant No.10374011)
文摘The cold isostatic press pretreatment process was adopted to prepare fine rare earth oxysulfide up-conversion phosphors with spherical shape, narrow size distribution and high luminescence efficiency. The upconversion optical characteristics and brightness of the blue (Y2O2SYb,Tm), green (Y2O2S: Yb,Er), red (Y2O3Yb,Er) emitter were also investigated, and a novel method was successfully developed for the brightness measurement of upconversion luminescence (UPL). It is shown that a white color can be obtained by the appropriate mixture of these primary blue, green and red emissions components. The Er3+ ions exhibit different upconversion mechanism in Y2O2S and Y2O3 host materials. The rare earth oxysulfide is an efficient upconversion matrix. The UPL brightness of Y2O2S: Yb,Er is 6.5 times higher than that of Y2O3: Yb,Er, and Y2O2S: Yb,Er shows UPL brightness of 1100 cd/m2 under 5.56 W/cm2 power density using a 980 nm laser diode.
