以硝酸铈和尿素为原料,1,3,5苯三甲酸为配体,采用简单的静电自组装法合成了铈金属有机框架(Ce-BTC)和石墨相氮化碳(g-C_(3)N_(4))的复合材料(Ce-BTC/g-C_(3)N_(4)),用于二氧化碳还原制一氧化碳的研究,并探索Ce-BTC的复合对g-C_(3)N_(4)...以硝酸铈和尿素为原料,1,3,5苯三甲酸为配体,采用简单的静电自组装法合成了铈金属有机框架(Ce-BTC)和石墨相氮化碳(g-C_(3)N_(4))的复合材料(Ce-BTC/g-C_(3)N_(4)),用于二氧化碳还原制一氧化碳的研究,并探索Ce-BTC的复合对g-C_(3)N_(4)性能的影响机制。利用X射线衍射、红外光谱、扫描电子显微镜、紫外-可见光吸收光谱、荧光光谱、阻抗、光电流测试和CO_(2)还原性能测试对复合材料的结构、形貌、光电学性能及催化性能进行研究。结果表明Ce-BTC与g-C_(3)N_(4)的复合可能使得g-C_(3)N_(4)层间距发生改变,在细化晶体颗粒的同时提高样品比表面积,使复合样品获得更高的可见光捕获能力且载流子的分离效率更高;在仅加入1 mL H2O作为质子提供源的前提下,Ce-BTC/g-C_(3)N_(4)-3拥有最优光催化性能。CO产率为19.02μmol/(h·g),是g-C_(3)N_(4)的2.25倍,循环测试后催化性能基本保持稳定。展开更多
Sinter is the core raw material for blast furnaces.Flue pressure,which is an important state parameter,affects sinter quality.In this paper,flue pressure prediction and optimization were studied based on the shapley a...Sinter is the core raw material for blast furnaces.Flue pressure,which is an important state parameter,affects sinter quality.In this paper,flue pressure prediction and optimization were studied based on the shapley additive explanation(SHAP)to predict the flue pressure and take targeted adjustment measures.First,the sintering process data were collected and processed.A flue pressure prediction model was then constructed after comparing different feature selection methods and model algorithms using SHAP+extremely random-ized trees(ET).The prediction accuracy of the model within the error range of±0.25 kPa was 92.63%.SHAP analysis was employed to improve the interpretability of the prediction model.The effects of various sintering operation parameters on flue pressure,the relation-ship between the numerical range of key operation parameters and flue pressure,the effect of operation parameter combinations on flue pressure,and the prediction process of the flue pressure prediction model on a single sample were analyzed.A flue pressure optimization module was also constructed and analyzed when the prediction satisfied the judgment conditions.The operating parameter combination was then pushed.The flue pressure was increased by 5.87%during the verification process,achieving a good optimization effect.展开更多
We adopted the solution impregnation route with aluminum dihydrogen phosphate solution as liquid medium for effective surface modification on graphite substrate.The mass ratio of graphite to Al(H_(2)PO_(4))_(3) change...We adopted the solution impregnation route with aluminum dihydrogen phosphate solution as liquid medium for effective surface modification on graphite substrate.The mass ratio of graphite to Al(H_(2)PO_(4))_(3) changed from 0.5:1 to 4:1,and the impregnation time changed from 1 to 7 h.The typical composite phase change thermal storage materials doped with the as-treated graphite were fabricated using form-stable technique.To investigate the oxidation and anti-oxidation behavior of the impregnated graphite at high temperatures,the samples were put into a muffle furnace for a cyclic heat test.Based on SEM,EDS,DSC techniques,analyses on the impregnated technique suggested an optimized processing conditions of a 3 h impregnation time with the ratio of graphite:Al(H_(2)PO_(4))_(3) as 1:3 for graphite impregnation treatment.Further investigations on high-temperature phase change heat storage materials doped by the treated graphite suggested excellent oxidation resistance and thermal cycling performance.展开更多
Ceramic dielectric materials with high dielectric strength and mechanisms of their internal factors affecting dielectric strength are significantly valuable for industrial application,especially for selection of suita...Ceramic dielectric materials with high dielectric strength and mechanisms of their internal factors affecting dielectric strength are significantly valuable for industrial application,especially for selection of suitable dielectric materials for high-power microwave transmission devices and reliable power transmission.Pure magnesium oxide(MgO),a kind of ceramic dielectric material,possesses great application potential in high-power microwave transmission devices due to its high theoretical dielectric strength,low dielectric constant,and low dielectric loss properties,but its application is limited by high sintering temperature during preparation.This work presented the preparation of a new type of multiphase ceramics based on MgO,which was MgO-1%ZrO_(2)-1%CaCO_(3-x)%MnCO_(3)(MZCM_(x),x=0,0.25,0.50,1.00,1.50,in molar),and their phase structures,morphological features,and dielectric properties were investigated.It was found that inclusion of ZrO_(2) and CaCO_(3) effectively inhibited excessive growth of MgO grains by formation of second phase,while addition of MnCO_(3) promoted the grain boundary diffusion process during the sintering process and reduced activation energy for the grain growth,resulting in a lower ceramic sintering temperature.Excellent performance,including high dielectric strength(Eb=92.3 kV/mm)and quality factor(Q×f=216642 GHz),simultaneously accompanying low dielectric loss(<0.03%),low temperature coefficient of dielectric constant(20.3×10^(–6)℃^(–1),85℃)and resonance frequency(–12.54×10^(–6)℃^(–1)),was achieved in MZCM1.00 ceramics under a relatively low sintering temperature of 1350℃.This work offers an effective solution for selecting dielectric materials for high-power microwave transmission devices.展开更多
采用高温固相法制备了SrZrSi_(2)O_(7):Ce^(3+),Mn^(2+)荧光粉。通过X射线衍射(X-ray Power Diffractometer,XRD)、激发和发射光谱及电子显微分析对材料的分子结构、显微形貌、发光特性和能量传递机理进行了研究。结果表明,荧光粉的主...采用高温固相法制备了SrZrSi_(2)O_(7):Ce^(3+),Mn^(2+)荧光粉。通过X射线衍射(X-ray Power Diffractometer,XRD)、激发和发射光谱及电子显微分析对材料的分子结构、显微形貌、发光特性和能量传递机理进行了研究。结果表明,荧光粉的主晶相是单斜晶系的SrZrSi_(2)O_(7),Ce^(3+)离子和Mn^(2+)离子占据一部分Sr^(2+)离子的晶体学格位。在296 nm激发下,可以观察到来自Ce^(3+)离子的蓝光发射峰,归属于Ce^(3+)离子的5d→4f能级跃迁。在544 nm处,有来自Mn^(2+)离子的绿光发射峰,归因于Mn^(2+)离子的^(4)T_(1)(4G)-^(6)A_(1)(6S)自旋禁止跃迁,表明发生了从Ce^(3+)离子到Mn^(2+)离子的能量传递过程,为设计蓝光到绿光之间可控制备的新型荧光粉提供了理论和实验的信息。展开更多
A procedure of low temperature solid-phase sintering（LTSS） was carried out to fabricate sintered metal fibrous media（SMFM） with high specific surface area.Stainless steel fibers which were produced by cutting proc...A procedure of low temperature solid-phase sintering（LTSS） was carried out to fabricate sintered metal fibrous media（SMFM） with high specific surface area.Stainless steel fibers which were produced by cutting process were first plated with a coarse copper coating layer by electroless plating process.A low-temperature sintering process was then completed at about 800 °C for 1 h under the protection of hydrogen atmosphere.The results show that a novel SMFM with complex surface morphology and high specific surface area（0.2 m2/g） can be obtained in this way.The effect of sintering temperature on the surface morphology and specific surface area of SMFM was studied by means of scanning electron microscopy and Brunauer-Emmett-Teller.The damage of micro-structure during the sintering process mainly contributed to the loss of specific surface area of SMFM and the optimal sintering temperature was 800 °C.展开更多
Fabrication, characterization and performance of a porous metal-fiber sintered felt （PMFSF） based on multi-tooth cutting and solid-phase sintering were studied. The PMFSF was used as the anodic methanol barrier in a...Fabrication, characterization and performance of a porous metal-fiber sintered felt （PMFSF） based on multi-tooth cutting and solid-phase sintering were studied. The PMFSF was used as the anodic methanol barrier in a passive air-breathing direct methanol fuel cell to mitigate the effects of methanol crossover. Compared with the commercial SUS316L felt made of bundle-drawn fibers, this self-made PMFSF has larger pore diameter, polarized pore distribution, irregular fiber shape, rougher surface, lower mass flow resistance and evident hydrophobicity. The results reveal that the use of a PMFSF significantly enhances the cell performance since it helps to maintain a balance between the reactant and product management while depressing methanol crossover. The PMFSF with a porosity of 70% yields the highest cell performance at a methanol concentration of 4 mol/L.展开更多
文摘以硝酸铈和尿素为原料,1,3,5苯三甲酸为配体,采用简单的静电自组装法合成了铈金属有机框架(Ce-BTC)和石墨相氮化碳(g-C_(3)N_(4))的复合材料(Ce-BTC/g-C_(3)N_(4)),用于二氧化碳还原制一氧化碳的研究,并探索Ce-BTC的复合对g-C_(3)N_(4)性能的影响机制。利用X射线衍射、红外光谱、扫描电子显微镜、紫外-可见光吸收光谱、荧光光谱、阻抗、光电流测试和CO_(2)还原性能测试对复合材料的结构、形貌、光电学性能及催化性能进行研究。结果表明Ce-BTC与g-C_(3)N_(4)的复合可能使得g-C_(3)N_(4)层间距发生改变,在细化晶体颗粒的同时提高样品比表面积,使复合样品获得更高的可见光捕获能力且载流子的分离效率更高;在仅加入1 mL H2O作为质子提供源的前提下,Ce-BTC/g-C_(3)N_(4)-3拥有最优光催化性能。CO产率为19.02μmol/(h·g),是g-C_(3)N_(4)的2.25倍,循环测试后催化性能基本保持稳定。
基金supported by the General Program of the National Natural Science Foundation of China(No.52274326)the China Baowu Low Carbon Metallurgy Innovation Foundation(No.BWLCF202109)the Seventh Batch of Ten Thousand Talents Plan of China(No.ZX20220553).
文摘Sinter is the core raw material for blast furnaces.Flue pressure,which is an important state parameter,affects sinter quality.In this paper,flue pressure prediction and optimization were studied based on the shapley additive explanation(SHAP)to predict the flue pressure and take targeted adjustment measures.First,the sintering process data were collected and processed.A flue pressure prediction model was then constructed after comparing different feature selection methods and model algorithms using SHAP+extremely random-ized trees(ET).The prediction accuracy of the model within the error range of±0.25 kPa was 92.63%.SHAP analysis was employed to improve the interpretability of the prediction model.The effects of various sintering operation parameters on flue pressure,the relation-ship between the numerical range of key operation parameters and flue pressure,the effect of operation parameter combinations on flue pressure,and the prediction process of the flue pressure prediction model on a single sample were analyzed.A flue pressure optimization module was also constructed and analyzed when the prediction satisfied the judgment conditions.The operating parameter combination was then pushed.The flue pressure was increased by 5.87%during the verification process,achieving a good optimization effect.
基金Funded by Scientific and Technological Innovation Project of Carbon Emission Peak and Carbon Neutrality of Jiangsu Province(No.BE2022028-4)。
文摘We adopted the solution impregnation route with aluminum dihydrogen phosphate solution as liquid medium for effective surface modification on graphite substrate.The mass ratio of graphite to Al(H_(2)PO_(4))_(3) changed from 0.5:1 to 4:1,and the impregnation time changed from 1 to 7 h.The typical composite phase change thermal storage materials doped with the as-treated graphite were fabricated using form-stable technique.To investigate the oxidation and anti-oxidation behavior of the impregnated graphite at high temperatures,the samples were put into a muffle furnace for a cyclic heat test.Based on SEM,EDS,DSC techniques,analyses on the impregnated technique suggested an optimized processing conditions of a 3 h impregnation time with the ratio of graphite:Al(H_(2)PO_(4))_(3) as 1:3 for graphite impregnation treatment.Further investigations on high-temperature phase change heat storage materials doped by the treated graphite suggested excellent oxidation resistance and thermal cycling performance.
基金Student Training Program for Innovation and Entrepreneurship of Hangzhou Institute for Advanced Study,UCAS(CXCY20230305)Chinese Academy of Sciences Key Project(ZDRW-CN-2021-3-1-18)。
文摘Ceramic dielectric materials with high dielectric strength and mechanisms of their internal factors affecting dielectric strength are significantly valuable for industrial application,especially for selection of suitable dielectric materials for high-power microwave transmission devices and reliable power transmission.Pure magnesium oxide(MgO),a kind of ceramic dielectric material,possesses great application potential in high-power microwave transmission devices due to its high theoretical dielectric strength,low dielectric constant,and low dielectric loss properties,but its application is limited by high sintering temperature during preparation.This work presented the preparation of a new type of multiphase ceramics based on MgO,which was MgO-1%ZrO_(2)-1%CaCO_(3-x)%MnCO_(3)(MZCM_(x),x=0,0.25,0.50,1.00,1.50,in molar),and their phase structures,morphological features,and dielectric properties were investigated.It was found that inclusion of ZrO_(2) and CaCO_(3) effectively inhibited excessive growth of MgO grains by formation of second phase,while addition of MnCO_(3) promoted the grain boundary diffusion process during the sintering process and reduced activation energy for the grain growth,resulting in a lower ceramic sintering temperature.Excellent performance,including high dielectric strength(Eb=92.3 kV/mm)and quality factor(Q×f=216642 GHz),simultaneously accompanying low dielectric loss(<0.03%),low temperature coefficient of dielectric constant(20.3×10^(–6)℃^(–1),85℃)and resonance frequency(–12.54×10^(–6)℃^(–1)),was achieved in MZCM1.00 ceramics under a relatively low sintering temperature of 1350℃.This work offers an effective solution for selecting dielectric materials for high-power microwave transmission devices.
文摘采用高温固相法制备了SrZrSi_(2)O_(7):Ce^(3+),Mn^(2+)荧光粉。通过X射线衍射(X-ray Power Diffractometer,XRD)、激发和发射光谱及电子显微分析对材料的分子结构、显微形貌、发光特性和能量传递机理进行了研究。结果表明,荧光粉的主晶相是单斜晶系的SrZrSi_(2)O_(7),Ce^(3+)离子和Mn^(2+)离子占据一部分Sr^(2+)离子的晶体学格位。在296 nm激发下,可以观察到来自Ce^(3+)离子的蓝光发射峰,归属于Ce^(3+)离子的5d→4f能级跃迁。在544 nm处,有来自Mn^(2+)离子的绿光发射峰,归因于Mn^(2+)离子的^(4)T_(1)(4G)-^(6)A_(1)(6S)自旋禁止跃迁,表明发生了从Ce^(3+)离子到Mn^(2+)离子的能量传递过程,为设计蓝光到绿光之间可控制备的新型荧光粉提供了理论和实验的信息。
基金Project (50930005) supported by the National Natural Science Foundation of ChinaProject (U0834002) supported by the Key Programof NSFC-Guangdong Joint Funds of China+1 种基金Project (LYM09024) supported by Training Program for Excellent Young Teachers withInnovation of Guangdong University, ChinaProject (2009ZM0121) supported by the Fundamental Research Funds for the CentralUniversities of South China University of Technology,China
文摘A procedure of low temperature solid-phase sintering（LTSS） was carried out to fabricate sintered metal fibrous media（SMFM） with high specific surface area.Stainless steel fibers which were produced by cutting process were first plated with a coarse copper coating layer by electroless plating process.A low-temperature sintering process was then completed at about 800 °C for 1 h under the protection of hydrogen atmosphere.The results show that a novel SMFM with complex surface morphology and high specific surface area（0.2 m2/g） can be obtained in this way.The effect of sintering temperature on the surface morphology and specific surface area of SMFM was studied by means of scanning electron microscopy and Brunauer-Emmett-Teller.The damage of micro-structure during the sintering process mainly contributed to the loss of specific surface area of SMFM and the optimal sintering temperature was 800 °C.
基金Projects(50930005,51075155)supported by the National Natural Science Foundation of ChinaProject(20100172110001)supported by PhD Programs Foundation of Ministry of Education of China
文摘Fabrication, characterization and performance of a porous metal-fiber sintered felt （PMFSF） based on multi-tooth cutting and solid-phase sintering were studied. The PMFSF was used as the anodic methanol barrier in a passive air-breathing direct methanol fuel cell to mitigate the effects of methanol crossover. Compared with the commercial SUS316L felt made of bundle-drawn fibers, this self-made PMFSF has larger pore diameter, polarized pore distribution, irregular fiber shape, rougher surface, lower mass flow resistance and evident hydrophobicity. The results reveal that the use of a PMFSF significantly enhances the cell performance since it helps to maintain a balance between the reactant and product management while depressing methanol crossover. The PMFSF with a porosity of 70% yields the highest cell performance at a methanol concentration of 4 mol/L.
