This paper reports a type of highly sensitive temperature sensor utilizing AlN-on-Si resonators with coupled-beam structures of double-and triple-ended-tuning-fork(D/TETF).For both resonators,the out-of-plane flexural...This paper reports a type of highly sensitive temperature sensor utilizing AlN-on-Si resonators with coupled-beam structures of double-and triple-ended-tuning-fork(D/TETF).For both resonators,the out-of-plane flexural mode is adopted as it favors the effect of thermal mismatch between the composite layers inherent to the AlN-on-Si structure and thus helps attain a large temperature coeficient of resonant frequency(TCF).The analytical model to calculate TCF values of D/TETF AIN-on-Si resonators is provided,which agrees well with the finite-element simulation and experimental results.The resonant temperature sensor is built by closing the loop of the AlN-on-Si resonator,a transimpedance amplifer,a low-pass flter,and a phase shifter to form an oscillator,the output frequency of which shifts proportionally to the ambient temperature.The measured sensitivities of the temperature sensors using D/TETF resonators are better than-1000 ppm/℃in the temperature range of 25℃~60℃,showing great potential to fulfll the on-chip temperature compensation scheme for cofabricated sensors.展开更多
This work presents a single-structure 3-axis Lorentz force magnetometer(LFM)based on an AlN-on-Si MEMS resonator.The operation of the proposed LFM relies on the flexible manipulation of applied excitation currents in ...This work presents a single-structure 3-axis Lorentz force magnetometer(LFM)based on an AlN-on-Si MEMS resonator.The operation of the proposed LFM relies on the flexible manipulation of applied excitation currents in different directions and frequencies,enabling the effective actuation of two mechanical vibration modes in a single device for magnetic field measurements in three axes.Specifically,the excited out-of-plane drum-like mode at 277 kHz is used for measuring the x-and y-axis magnetic fields,while the in-plane square-extensional mode at 5.4 MHz is used for measuring the z-axis magnetic field.The different configurations of applied excitation currents ensure good crossinterference immunity among the three axes.Compared to conventional capacitive LFMs,the proposed piezoelectric LFM utilizes strong electromechanical coupling from the AlN layer,which allows it to operate at ambient pressure with a high sensitivity.To understand and analyze the measured results,a novel equivalent circuit model for the proposed LFM is also reported in this work,which serves to separate the effect of Lorentz force from the unwanted capacitive feedthrough.The demonstrated 3-axis LFM exhibits measured magnetic responsivities of 1.74 ppm/mT,1.83 ppm/mT and 6.75 ppm/mT in the x-,y-and z-axes,respectively,which are comparable to their capacitive counterparts.展开更多
Iron and steel slags are smelting wastes, mainly including blast furnace slag(BFS) and steel slag(SS) produced in the iron and steel industry. Utilization of iron and steel slags as resources for solving the problem o...Iron and steel slags are smelting wastes, mainly including blast furnace slag(BFS) and steel slag(SS) produced in the iron and steel industry. Utilization of iron and steel slags as resources for solving the problem of slag disposals has attracted much attention with increasing iron and steel smelting slags in China. Because the iron and steel slags contain calcium(Ca), magnesium(Mg), phosphorus(P), and silicon(Si), some have tried to use them as Si-and P-fertilizers, for producing Ca-Mg-P fertilizers, or as soil amendments in agriculture. However, in the iron metallurgical process, several pollutants in iron ores can inevitably transfer into iron and steel slags, resulting in the enrichment of pollutants both in BFS(mainly nickel(Ni), copper(Cu), mercury, zinc(Zn),cadmium(Cd), chromium(Cr), arsenic, lead, selenium, fluorine(F), and chlorine(Cl)) and in SS(mainly Ni, Cr, Cd, Zn, Cu, F, and Cl), in which some of pollutants(especially Cr, Ni, F, and Cl) exceed the limits of environmental quality standards for soils and groundwater. The elements of manganese, barium,and vanadium in iron and steel slags are higher than the background values of soil environment. In order to ensure soil health, food safety, and environmental quality, it is suggested that those industrial solid wastes, such as iron and steel slags, without any pretreatment for reducing harmful pollutants and with environmental safety risk, should not be allowed to use for soil remediation or conditioning directly in farmlands by solid waste disposal methods, to prevent pollutants from entering food chain and harming human health.展开更多
The wettability of molten Al_(x)CoCrCuFeNi(x is from 0 to 1.5,mol.%)high-entropy alloys(HEA)on a WC substrate was measured using a modified sessile drop method at 1823 K in an argon atmosphere.The wetting behaviors an...The wettability of molten Al_(x)CoCrCuFeNi(x is from 0 to 1.5,mol.%)high-entropy alloys(HEA)on a WC substrate was measured using a modified sessile drop method at 1823 K in an argon atmosphere.The wetting behaviors and interfacial characteristics between HEAs and WC were studied.Good wettability with final equilibrium contact angles of 0.5°-4.6°is obtained,and addition of Al deteriorates the wettability of the HEAs.The wetting of Al_(x)CoCrCuFeNi/WC system can be roughly divided into an initially sharp spreading stage and a subsequent steady-state phase.In the first stage,the adsorption of Cr atoms at the solid-liquid interface primarily contributes to the wetting,and the contact angle drastically reduces.However,both the wetting behavior and interfacial microstructure are determined by the Al content of the HEA in the next stage.For x≤0.5,the wetting is mainly driven by the dissolution of WC,although a few reaction products of(W,Cr)_(2)C are observed.Moreover,an obvious dissolution pit appears at the surface of the substrate.When the Al content of x≥1,the interfacial reaction is dominant in competition with the dissolution of WC,and massive reaction products precipitate at the HEA/WC interface,which leads to the formation of a continuous reaction layer.展开更多
基金supported in part by the National Natural Science Foundation of China(No.62004029,No.62074029,No.61804023,and No.61971108)the Key Research and Development Program of Sichuan Province(No.2020ZHCG0038)+1 种基金the Sichuan Science and Technology Program(No.2019YJ0198 and No.2020YJ0015)the Fundamental Research Funds for the Central Universities(No.ZYGX2019Z002)。
文摘This paper reports a type of highly sensitive temperature sensor utilizing AlN-on-Si resonators with coupled-beam structures of double-and triple-ended-tuning-fork(D/TETF).For both resonators,the out-of-plane flexural mode is adopted as it favors the effect of thermal mismatch between the composite layers inherent to the AlN-on-Si structure and thus helps attain a large temperature coeficient of resonant frequency(TCF).The analytical model to calculate TCF values of D/TETF AIN-on-Si resonators is provided,which agrees well with the finite-element simulation and experimental results.The resonant temperature sensor is built by closing the loop of the AlN-on-Si resonator,a transimpedance amplifer,a low-pass flter,and a phase shifter to form an oscillator,the output frequency of which shifts proportionally to the ambient temperature.The measured sensitivities of the temperature sensors using D/TETF resonators are better than-1000 ppm/℃in the temperature range of 25℃~60℃,showing great potential to fulfll the on-chip temperature compensation scheme for cofabricated sensors.
基金supported by the National Natural Science Foundation of China(No.62004029,No.62074029,No.61804023,No.61971108)the National Key Research and Development Program of China(No.2022YFB3206100,2022YFB3203602)+1 种基金the Key Research and Development Program of Sichuan Province(No.2022JDTD0020,No.2020ZHCG0038)the Sichuan Science and Technology Program(No.2020YJ0015).
文摘This work presents a single-structure 3-axis Lorentz force magnetometer(LFM)based on an AlN-on-Si MEMS resonator.The operation of the proposed LFM relies on the flexible manipulation of applied excitation currents in different directions and frequencies,enabling the effective actuation of two mechanical vibration modes in a single device for magnetic field measurements in three axes.Specifically,the excited out-of-plane drum-like mode at 277 kHz is used for measuring the x-and y-axis magnetic fields,while the in-plane square-extensional mode at 5.4 MHz is used for measuring the z-axis magnetic field.The different configurations of applied excitation currents ensure good crossinterference immunity among the three axes.Compared to conventional capacitive LFMs,the proposed piezoelectric LFM utilizes strong electromechanical coupling from the AlN layer,which allows it to operate at ambient pressure with a high sensitivity.To understand and analyze the measured results,a novel equivalent circuit model for the proposed LFM is also reported in this work,which serves to separate the effect of Lorentz force from the unwanted capacitive feedthrough.The demonstrated 3-axis LFM exhibits measured magnetic responsivities of 1.74 ppm/mT,1.83 ppm/mT and 6.75 ppm/mT in the x-,y-and z-axes,respectively,which are comparable to their capacitive counterparts.
基金supported by the Special Program for Fertilizer Registration of Ministry of Agriculture and Rural Affairs of China (No. 2130109)。
文摘Iron and steel slags are smelting wastes, mainly including blast furnace slag(BFS) and steel slag(SS) produced in the iron and steel industry. Utilization of iron and steel slags as resources for solving the problem of slag disposals has attracted much attention with increasing iron and steel smelting slags in China. Because the iron and steel slags contain calcium(Ca), magnesium(Mg), phosphorus(P), and silicon(Si), some have tried to use them as Si-and P-fertilizers, for producing Ca-Mg-P fertilizers, or as soil amendments in agriculture. However, in the iron metallurgical process, several pollutants in iron ores can inevitably transfer into iron and steel slags, resulting in the enrichment of pollutants both in BFS(mainly nickel(Ni), copper(Cu), mercury, zinc(Zn),cadmium(Cd), chromium(Cr), arsenic, lead, selenium, fluorine(F), and chlorine(Cl)) and in SS(mainly Ni, Cr, Cd, Zn, Cu, F, and Cl), in which some of pollutants(especially Cr, Ni, F, and Cl) exceed the limits of environmental quality standards for soils and groundwater. The elements of manganese, barium,and vanadium in iron and steel slags are higher than the background values of soil environment. In order to ensure soil health, food safety, and environmental quality, it is suggested that those industrial solid wastes, such as iron and steel slags, without any pretreatment for reducing harmful pollutants and with environmental safety risk, should not be allowed to use for soil remediation or conditioning directly in farmlands by solid waste disposal methods, to prevent pollutants from entering food chain and harming human health.
基金the National Key R&D Program of China(No.2017YFB0305702)the Major Special Project for Industry-university-research Collaborative Innovation of Guangzhou City(No.201604020139)+1 种基金the Project for Science and Technology Program of Guangdong Province(No.2016A020220005)the Major Special Projects for Science and Technology Program of Guangdong Province(Nos.2014B010129002 and 2019B090907001),China。
文摘The wettability of molten Al_(x)CoCrCuFeNi(x is from 0 to 1.5,mol.%)high-entropy alloys(HEA)on a WC substrate was measured using a modified sessile drop method at 1823 K in an argon atmosphere.The wetting behaviors and interfacial characteristics between HEAs and WC were studied.Good wettability with final equilibrium contact angles of 0.5°-4.6°is obtained,and addition of Al deteriorates the wettability of the HEAs.The wetting of Al_(x)CoCrCuFeNi/WC system can be roughly divided into an initially sharp spreading stage and a subsequent steady-state phase.In the first stage,the adsorption of Cr atoms at the solid-liquid interface primarily contributes to the wetting,and the contact angle drastically reduces.However,both the wetting behavior and interfacial microstructure are determined by the Al content of the HEA in the next stage.For x≤0.5,the wetting is mainly driven by the dissolution of WC,although a few reaction products of(W,Cr)_(2)C are observed.Moreover,an obvious dissolution pit appears at the surface of the substrate.When the Al content of x≥1,the interfacial reaction is dominant in competition with the dissolution of WC,and massive reaction products precipitate at the HEA/WC interface,which leads to the formation of a continuous reaction layer.