Based on the Landau-Dovenshire theory,the thermodynamic potential of(111) oriented films is constructed to investigate the pyroelectric properties of Pb(Zr_(1-x)Ti_x)O_3 thin films.Due to the presence of nonlinear cou...Based on the Landau-Dovenshire theory,the thermodynamic potential of(111) oriented films is constructed to investigate the pyroelectric properties of Pb(Zr_(1-x)Ti_x)O_3 thin films.Due to the presence of nonlinear coupling terms resulted from the(111) epitaxy with substrates,the effects of misfit strain and electric field on the phase transitions at room temperature are more complex than that of(001) and(110) oriented films.Pb(Zr_(1-x)Ti_x)O_3 thin films with the Ti composition around the morphotropic phase boundary(MPB) have the giant dielectric and pyroelectric properties.Moreover,Pb(Zr_(1-x)Ti_x)O_3 thin films grown on the tensile substrates which induce the triclinic γ phase have the larger dielectric and pyroelectric properties than that on the compressive substrates.Therefore,the physical properties of(111)oriented Pb(Zr_(1-x)Ti_x)O_3 thin films can be adjusted by choosing the suitable substrates.展开更多
In this paper, the effective pyroelectric coefficient and polarization offset of the compositionally step-like graded multilayer ferroelectric structures have been studied by use of the first-principles approach. It i...In this paper, the effective pyroelectric coefficient and polarization offset of the compositionally step-like graded multilayer ferroelectric structures have been studied by use of the first-principles approach. It is exhibited that the dielectric gradient has a nontrivial influence on the effective pyroelectric coefficient, but has a little influence on the polarization offset; and the polarization gradient plays an important role in the abnormal hysteresis loop phenomenon of the co.mpositionally step-like graded ferroelectric structures. Moreover, the origin of the polarization offset is explored,which can be attributed to the polarization gradient in the compositionally step-like graded structure.展开更多
A finite element approach based on the micromechanics was performed to estimate the multi-field properties of electro-magneto-thermoelastic composites. The thermal field and the involved pyroelectric and pyromagnetic ...A finite element approach based on the micromechanics was performed to estimate the multi-field properties of electro-magneto-thermoelastic composites. The thermal field and the involved pyroelectric and pyromagnetic effect of the multi-phase composite materials were taken into account in the investigation and implemented in the finite element modeling. The multi- fields related to the electric field, magnetic field, deformation and temperature field, as well as their coupling effects of the smart composites under periodic boundary conditions were obtained numerically. Especially, by means of the homogenization approximation, the effective thermal ex- pansion coefficients, pyroelectric coefficients, pyromagnetic coefficients and other elastic, electric, and magnetic properties for the piezoelectric material, piezomagnetic material and magnetoelec- tric material were calculated, respectively. Some results are compared to the theoretical predictions by the well-known Mori-Tanaka method to show good agreements.展开更多
The typical wastewater treatment is focused on the photocatalytic efficiency in the degradation of organic pollutants,with little attention to the involved selectivity which may correlate with toxicant residues.Herein...The typical wastewater treatment is focused on the photocatalytic efficiency in the degradation of organic pollutants,with little attention to the involved selectivity which may correlate with toxicant residues.Herein,an electron localization strategy for specific O2 adsorption/activation enabled by photothermal/pyroelectric effect and in situ constructed active centers of single-atom Co and oxygen vacancy(Co-O_(V))on the Co/BiOCl-O_(V)photocatalyst was developed for photocatalytic degradation of glyphosate(GLP)wastewater of high performance/selectivity.Under full-spectrum-light irradiation,a high GLP degradation rate of 99.8%with over 90%C-P bond-breaking selectivity was achieved within 2 h,while effectively circumventing toxicant residues such as aminomethylphosphonic acid(AMPA).X-ray absorption spectroscopy and relevant characterizations expounded the tailored anchoring of Co single atoms onto the BiOCl-O_(V)carrier and photothermal/pyroelectric effect.The oriented formation of more•O_(2)^(−)on Co/BiOCl-O_(V)could be achieved with the Co-O_(V)coupled center that had excellent O2 adsorption/activation capacity,as demonstrated by quantum calculations.The formed unique Co-O_(V)active sites could largely decrease the C-P bond-breaking energy barrier,thus greatly improving the selectivity toward the initial C-P bond scission and the activity in subsequent conversion steps in the directional photocatalytic degradation of GLP.The electron localization strategy by in situ constructing the coupled active centers provides an efficient scheme and new insights for the low-toxic photodegradation of organic pollutants containing C-X bonds.展开更多
Photocatalytic transformation of biomass into biofuels and value-added chemicals is of great significance for carbon neutrality.Metal-free carbon nitride has extensive applications but with almost no absorption and ut...Photocatalytic transformation of biomass into biofuels and value-added chemicals is of great significance for carbon neutrality.Metal-free carbon nitride has extensive applications but with almost no absorption and utilization of near-infrared light,accounting for 50%of sunlight.Here,a molten salt-assisted in-plane“stitching”and interlayer“cutting”protocol is developed for constructing a highly crystalline carbon nitride catalyst containing structural oxygen(HC-CN).HC-CN is highly efficient for the photothermal cascade transformation of biomass-derived glucose into lactic acid(LA)with an unprecedented yield(94.3%)at 25°C under full-spectrum light irradiation within 50 min,which is also applicable to quantitatively photo-upgrading various saccharides.Theoretical calculations expound that the light-induced glucose-to-catalyst charge transfer can activate the Cβ-H bond to promote the rate-determining step of intramolecular hydrogen shift in glucose-to-fructose isomerization.Meanwhile,the introduced structural oxygen in HC-CN can not only facilitate the local electric field formation to achieve rapid charge transport/separation and regulate selective·O^(-)_(2)generation for oriented C3-C4 bond cleavage of fructose but also narrow the energy band gap to broaden the light absorption range of HC-CN,contributing to enhanced LA production without exogenous heating.Moreover,HC-CN is highly recyclable and exhibits negligible environmental burden and low energy consumption,as disclosed by the life cycle assessment.Tailored construction of full-spectrum light adsorption and versatile reaction sites provides a reference for implementing multi-step biomass and organic conversion processes under mild conditions.展开更多
Thermocatalytic biofuel production via(trans)esterification can be highly enabled by solid alkali catalysts,while often suffering from serious saponification and unsatisfactory catalyst reusability when the bases are ...Thermocatalytic biofuel production via(trans)esterification can be highly enabled by solid alkali catalysts,while often suffering from serious saponification and unsatisfactory catalyst reusability when the bases are directly used for high-acid-value oils.Herein,room temperature single-step upgrading of various non-edible oils(acid values:66-21.5 mgKOHg^(-1))to biodiesel(>97%yields)after 37 min with satisfactory fuel properties was achieved under solar irradiation over a renewable heterogeneous Lewis base catalyst(Cs/GL-4),which was composed of adjacent Cs single atoms(ACs SA)anchored on graphene-like(GL)biomaterial.Infrared thermal imaging showed that Cs/GL-4 had good photothermal performance,while quantum calculations and COMSOL multiphysics disclosed that ACs S A exhibited the prominent pyroelectric effect which was closely correlated with super-alkalinity and good acid resistance,both contributing to rapidly producing biodiesel of high efficiency under ambient conditions(25℃).Moreover,the pronounced activity and reusability of Cs/GL-4 were verified by reaction kinetics and recycling studies.The life cycle assessment indicated significant advantages in terms of energy savings(68.86 MJ kg^(-1))and negative carbon emission(-2.42 kg_(CO_(2eq))kg^(-1))associated with the photothermaldriven protocol for renewable diesel production,suggesting its relatively positive overall environmental impact.The electronic structure of adjacent atomic sites further enhanced by the photothermal effect provides an alternative reference for the one-step and mild upgrading of raw biomass.展开更多
In order to improVe the pyroelectric properties of TGS crystals,the different dopants were selected according to crystal chemistry principle and pyroelectric effect of molecules and ionic group to grow new modified TG...In order to improVe the pyroelectric properties of TGS crystals,the different dopants were selected according to crystal chemistry principle and pyroelectric effect of molecules and ionic group to grow new modified TGS crystals. The experimental results show that some dopants can improve the pyroelectric proPerties of TGS crystals.展开更多
Tactile sensors are a potential solution for material identification.However,current potential tactile sensors for material identification are pressed,expensive,and applications-confined.Here we report a clamped-on py...Tactile sensors are a potential solution for material identification.However,current potential tactile sensors for material identification are pressed,expensive,and applications-confined.Here we report a clamped-on pyroelectric tactile sensor on the basis of a ferroelectric Bi_(0.5)Na_(0.5)TiO_(3) material to identify different film materials.The fabricated device exhibits different heat absorption capacities while in contact with different materials,leading to a different temperature change in the ferroelectric material under the same illumination.As a result,the device can recognize different materials by comparing the pyroelectric charge via integrating the obtained current under the same irradiation of 365nmlight-emitting diode.The clamped-on pyroelectric tactile sensor can identify six individual materials with a high accuracy of 98.8%and a fast response of 40 ms.All of the above processes can be accomplished with an intelligent material identification system.The device provides a new solution for material identification and lays a foundation for smart factories and laboratories.展开更多
It is desirable but always challenging to develop a cutting-edge tumor treatment strategy with high therapeutic efficacy,lesiontargeted precision and mild accessibility.Compared to traditional treatment modalities,pho...It is desirable but always challenging to develop a cutting-edge tumor treatment strategy with high therapeutic efficacy,lesiontargeted precision and mild accessibility.Compared to traditional treatment modalities,photodynamic therapy has been widely studied since the generation of reactive oxygen species(ROS)at cancerous lesions unprecedentedly offers a convenient approach for localized tumor eliminations.Nevertheless,the consumption of oxygen for ROS production in a hypoxic tumor microenvironment has dramatically limited its feasibility and efficacy.Herein,the engineered nanocomposites of BTO@PDA-ICGHA with photodynamic and pyroelectric performances have been fabricated and applied to the photodynamic-pyroelectric dynamic treatments.The continuing ROS production derived from intracellular oxygen(O_(2))and water(H_(2)O)by laser irradiation contributed to the superb tumor cell apoptosis and significant tumor growth inhibition.Thus,this study has validated a new concept by depositing the engineered nanocomposites at the tumor just like Trojan horses,facilitating ROS release as killers and exerting the NIR-induced cell apoptosis and tumor growth inhibition with high therapeutic efficiency and expectable translational perspectives.展开更多
A comprehensive study and detailed analysis of pyroelectric and electrocaloric effects in relaxor ferroelectrics based on lead magnesium niobate as a promising object for such investigations have been carried out.It w...A comprehensive study and detailed analysis of pyroelectric and electrocaloric effects in relaxor ferroelectrics based on lead magnesium niobate as a promising object for such investigations have been carried out.It was found that even at the maximum values of pyroelectric coefficients the electrocaloric response inextricably linked with the pyroelectric effect does not exceed 1°C in the temperature range from 10 to 60°C under DC electric field up to 60 kV/cm.These conditions are the most demanded for the operation of electrocaloric cooling devices.Vision for the future as to increasing the efficiency of the main elements for such devices is discussed.展开更多
Macroscopic polarization switching achieved through directional electron transfer or spin crossover(SCO)has attracted considerable attention because of its potential applications in data storage devices,sensors,and en...Macroscopic polarization switching achieved through directional electron transfer or spin crossover(SCO)has attracted considerable attention because of its potential applications in data storage devices,sensors,and energy converters.Here,by substituting the central metal and anion of a reported compound,[Fe(RR-cth)Co(SS-cth)(μ-dhbq)](AsF_(6))_(3),we obtained two dinuclear compounds that crystallize in the polar space group,P2_(1),[Fe(RR-cth)Ga(SS-cth)(μ-dhbq)](X)_(3)(X=AsF_(6)and ClO_(4)).Among them,complex 1(AsF_(6))_(3)exhibited a two-step magnetic transition,including SCO behavior near 50 K and a gradual valence tautomerism(VT)behavior that occurred over a wide temperature range up to at least 250 K.The SCO behavior of complex 1(AsF_(6))_(3)can be triggered by changes in temperature or the application of magnetic fields,leading to a polarization change of approximately 0.5μC cm^(−2).The transition entropy of 55.9 J K^(−1)mol^(−1)during the SCO process was obtained using the Clausius-Clapeyron equation.Contrarily,complex 1(ClO_(4))_(3)only exhibited gradual VT behavior from a low temperature to room temperature.Single-crystal X-ray diffraction,variable-temperature infrared spectroscopy,and pyroelectric measurements confirmed the gradual VT process that occurs over a wide temperature range in both complexes.This study broadens the range of polarization switching molecular systems by replacing the central metal and anion,thereby facilitating the development of multifunctional molecular materials.展开更多
A flexible,multi-site tactile and thermal sensor(MTTS)based on polyvinylidene fluoride(resolution 50×50)is reported.It can be used to implement spatial mapping caused by tactile and thermal events and record the ...A flexible,multi-site tactile and thermal sensor(MTTS)based on polyvinylidene fluoride(resolution 50×50)is reported.It can be used to implement spatial mapping caused by tactile and thermal events and record the two-dimensional motion trajectory of a tracked target object.The output voltage and current signal are recorded as amapping by sensing the external pressure and thermal radiation stimulus,and the response distribution is dynamically observed on the three-dimensional interface.Through the mapping relationship between the established piezoelectric and pyroelectric signals,the piezoelectric component and the pyroelectric component are effectively extracted from the composite signals.The MTTS has a good sensitivity for tactile and thermal detection,and the electrodes have good synchronism.In addition,the signal interference is less than 9.5%and decreases as the pressure decreases after the distance between adjacent sites exceeds 200μm.The integration of MTTS and signal processing units has potential applications in human-machine interaction systems,health status detection and smart assistive devices.展开更多
2-hydroxynaphthylidene-1′-naphthylamine(HNAN) and –NO_(2) modified HNAN(HNAN-NO_(2)) Schiff base compounds were synthesized and exhibited strong visible light absorption(<650 nm). These compounds were added to po...2-hydroxynaphthylidene-1′-naphthylamine(HNAN) and –NO_(2) modified HNAN(HNAN-NO_(2)) Schiff base compounds were synthesized and exhibited strong visible light absorption(<650 nm). These compounds were added to poly(vinylidene fluoride-trifluoroethylene)(P(VDF-Tr FE))ferroelectric polymer, obtaining composites with high photoelectric response under visible and infrared light. It was found that the modification of HNAN by the nitro group and the poling of the composites under a high electric field can greatly enhance the photoelectric response of the composites. The composites can generate high photovoltages of 1386 and352.7 mV under irradiation with near-infrared light(915 nm)and green light(532 nm). The mechanism of the photoelectric response of the composites under green light was explored and it was found that the response originates mainly from the coupling effect of the photothermal effect of the Schiff base and the pyroelectric effect of the ferroelectric polymer. The composites, which can be utilized as photodetector materials,are promising for next-generation artificial retina applications and the sensing capability of retina can be extended in a wide wavelength range from visible to infrared light.展开更多
Here,we present a study of the effective piezoelectric constant(e_(14_(e)))temperature dependence in strained[111]-oriented zinc-blende quantum wells(QWs)embedded within a semiconductor optical amplifier(SOA).We deter...Here,we present a study of the effective piezoelectric constant(e_(14_(e)))temperature dependence in strained[111]-oriented zinc-blende quantum wells(QWs)embedded within a semiconductor optical amplifier(SOA).We determined e_(14_(e)) using a method that was insensitive to the segregation phenomenon and to the temperature dependence of the bandgap energy,which required neither fitting parameters nor temperature-dependent expressions for energy and out-of-plane effective masses of electrons and heavy holes.An e_(14_(e))=−0.0534±0.0040 C·m^(−2) at 23°C was obtained for an SOA with 1.2 nm[111]-oriented strained In0.687Ga0.313As/In0.807Ga0.193As0.304P0.696 QWs.Unlike previously published research,where e_(14_(e)) magnitude increased as temperature rised,we extracted an e_(14_(e)) magnitude that decreased as temperature increased.展开更多
It has been established that in plates made of hot-pressed ferroelectric ceramics PZT-19(Tc=300℃),after metal electrodes from Ag are burned into opposite surfaces with different depths of mechanical damage,counter-di...It has been established that in plates made of hot-pressed ferroelectric ceramics PZT-19(Tc=300℃),after metal electrodes from Ag are burned into opposite surfaces with different depths of mechanical damage,counter-directional stationary deformation gradients and,accordingly,internal electric displacement fields create a stationary flexoelectric effect.As a result,unpolarized ceramics below the Curie temperature become a pyroelectric,and above it become a pyroelectric bolometer.After polishing the less damaged surface and replacing the Ag(valency v=3)electrode with Cr(v=6)by thermal evaporation in vacuum from the intact surface,a new thermally stable polarization is created,directed from the damaged surface in the interelectrode volume.Such plates have an asymmetric dielectric hysteresis loop,retain the values of the pyroelectric effect and piezoelectric effect in the ferroelectric phase,as well as the bolometric effect in the paraelectric phase after repeated heating cycles to 400℃ and cooling to T_(norm).展开更多
基金Supported by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe research fund of Jiangsu Province Cultivation base for State Key Laboratory of Photovoltaic Science and Technology+1 种基金Major Projects of Natural Science Research in Jiangsu Province under Grant Nos.15KJA43002,16KJD430006sponsored by Qing Lan Project of Education Department of Jiangsu Province
文摘Based on the Landau-Dovenshire theory,the thermodynamic potential of(111) oriented films is constructed to investigate the pyroelectric properties of Pb(Zr_(1-x)Ti_x)O_3 thin films.Due to the presence of nonlinear coupling terms resulted from the(111) epitaxy with substrates,the effects of misfit strain and electric field on the phase transitions at room temperature are more complex than that of(001) and(110) oriented films.Pb(Zr_(1-x)Ti_x)O_3 thin films with the Ti composition around the morphotropic phase boundary(MPB) have the giant dielectric and pyroelectric properties.Moreover,Pb(Zr_(1-x)Ti_x)O_3 thin films grown on the tensile substrates which induce the triclinic γ phase have the larger dielectric and pyroelectric properties than that on the compressive substrates.Therefore,the physical properties of(111)oriented Pb(Zr_(1-x)Ti_x)O_3 thin films can be adjusted by choosing the suitable substrates.
文摘In this paper, the effective pyroelectric coefficient and polarization offset of the compositionally step-like graded multilayer ferroelectric structures have been studied by use of the first-principles approach. It is exhibited that the dielectric gradient has a nontrivial influence on the effective pyroelectric coefficient, but has a little influence on the polarization offset; and the polarization gradient plays an important role in the abnormal hysteresis loop phenomenon of the co.mpositionally step-like graded ferroelectric structures. Moreover, the origin of the polarization offset is explored,which can be attributed to the polarization gradient in the compositionally step-like graded structure.
基金supported by the National Natural Science Foundation of China(No.11172117)Doctoral Fund of Ministry of Education of China(No.20120211110005)the Foundation for Innovative Research Groups of the NNSFC(No.11121202)
文摘A finite element approach based on the micromechanics was performed to estimate the multi-field properties of electro-magneto-thermoelastic composites. The thermal field and the involved pyroelectric and pyromagnetic effect of the multi-phase composite materials were taken into account in the investigation and implemented in the finite element modeling. The multi- fields related to the electric field, magnetic field, deformation and temperature field, as well as their coupling effects of the smart composites under periodic boundary conditions were obtained numerically. Especially, by means of the homogenization approximation, the effective thermal ex- pansion coefficients, pyroelectric coefficients, pyromagnetic coefficients and other elastic, electric, and magnetic properties for the piezoelectric material, piezomagnetic material and magnetoelec- tric material were calculated, respectively. Some results are compared to the theoretical predictions by the well-known Mori-Tanaka method to show good agreements.
基金supported by the National Natural Science Foundation of China(No.22368014)Guizhou Provincial S&T Project(Nos.GCC[2023]011,ZK[2022]011)Guizhou Provincial Higher Education Institution Program(No.Qianjiaoji[2023]082).
文摘The typical wastewater treatment is focused on the photocatalytic efficiency in the degradation of organic pollutants,with little attention to the involved selectivity which may correlate with toxicant residues.Herein,an electron localization strategy for specific O2 adsorption/activation enabled by photothermal/pyroelectric effect and in situ constructed active centers of single-atom Co and oxygen vacancy(Co-O_(V))on the Co/BiOCl-O_(V)photocatalyst was developed for photocatalytic degradation of glyphosate(GLP)wastewater of high performance/selectivity.Under full-spectrum-light irradiation,a high GLP degradation rate of 99.8%with over 90%C-P bond-breaking selectivity was achieved within 2 h,while effectively circumventing toxicant residues such as aminomethylphosphonic acid(AMPA).X-ray absorption spectroscopy and relevant characterizations expounded the tailored anchoring of Co single atoms onto the BiOCl-O_(V)carrier and photothermal/pyroelectric effect.The oriented formation of more•O_(2)^(−)on Co/BiOCl-O_(V)could be achieved with the Co-O_(V)coupled center that had excellent O2 adsorption/activation capacity,as demonstrated by quantum calculations.The formed unique Co-O_(V)active sites could largely decrease the C-P bond-breaking energy barrier,thus greatly improving the selectivity toward the initial C-P bond scission and the activity in subsequent conversion steps in the directional photocatalytic degradation of GLP.The electron localization strategy by in situ constructing the coupled active centers provides an efficient scheme and new insights for the low-toxic photodegradation of organic pollutants containing C-X bonds.
基金the Natural Science Foundation of China(22368014,22478087)the Guizhou Provincial S&T Project(GCC[2023]011,ZK[2022]011).
文摘Photocatalytic transformation of biomass into biofuels and value-added chemicals is of great significance for carbon neutrality.Metal-free carbon nitride has extensive applications but with almost no absorption and utilization of near-infrared light,accounting for 50%of sunlight.Here,a molten salt-assisted in-plane“stitching”and interlayer“cutting”protocol is developed for constructing a highly crystalline carbon nitride catalyst containing structural oxygen(HC-CN).HC-CN is highly efficient for the photothermal cascade transformation of biomass-derived glucose into lactic acid(LA)with an unprecedented yield(94.3%)at 25°C under full-spectrum light irradiation within 50 min,which is also applicable to quantitatively photo-upgrading various saccharides.Theoretical calculations expound that the light-induced glucose-to-catalyst charge transfer can activate the Cβ-H bond to promote the rate-determining step of intramolecular hydrogen shift in glucose-to-fructose isomerization.Meanwhile,the introduced structural oxygen in HC-CN can not only facilitate the local electric field formation to achieve rapid charge transport/separation and regulate selective·O^(-)_(2)generation for oriented C3-C4 bond cleavage of fructose but also narrow the energy band gap to broaden the light absorption range of HC-CN,contributing to enhanced LA production without exogenous heating.Moreover,HC-CN is highly recyclable and exhibits negligible environmental burden and low energy consumption,as disclosed by the life cycle assessment.Tailored construction of full-spectrum light adsorption and versatile reaction sites provides a reference for implementing multi-step biomass and organic conversion processes under mild conditions.
基金financially supported by the National Natural Science Foundation of China(Nos.22368014,and 22478087)Guizhou Provincial S&T Project(Nos.GCC[2023]011,and ZK[2022]011)+1 种基金Graduate Research Foundation of Guizhou Province(No.YJSKYJJ[2024]058)Guizhou Provincial Higher Education Institution Program(No.Qianjiaoji[2023]082)
文摘Thermocatalytic biofuel production via(trans)esterification can be highly enabled by solid alkali catalysts,while often suffering from serious saponification and unsatisfactory catalyst reusability when the bases are directly used for high-acid-value oils.Herein,room temperature single-step upgrading of various non-edible oils(acid values:66-21.5 mgKOHg^(-1))to biodiesel(>97%yields)after 37 min with satisfactory fuel properties was achieved under solar irradiation over a renewable heterogeneous Lewis base catalyst(Cs/GL-4),which was composed of adjacent Cs single atoms(ACs SA)anchored on graphene-like(GL)biomaterial.Infrared thermal imaging showed that Cs/GL-4 had good photothermal performance,while quantum calculations and COMSOL multiphysics disclosed that ACs S A exhibited the prominent pyroelectric effect which was closely correlated with super-alkalinity and good acid resistance,both contributing to rapidly producing biodiesel of high efficiency under ambient conditions(25℃).Moreover,the pronounced activity and reusability of Cs/GL-4 were verified by reaction kinetics and recycling studies.The life cycle assessment indicated significant advantages in terms of energy savings(68.86 MJ kg^(-1))and negative carbon emission(-2.42 kg_(CO_(2eq))kg^(-1))associated with the photothermaldriven protocol for renewable diesel production,suggesting its relatively positive overall environmental impact.The electronic structure of adjacent atomic sites further enhanced by the photothermal effect provides an alternative reference for the one-step and mild upgrading of raw biomass.
文摘In order to improVe the pyroelectric properties of TGS crystals,the different dopants were selected according to crystal chemistry principle and pyroelectric effect of molecules and ionic group to grow new modified TGS crystals. The experimental results show that some dopants can improve the pyroelectric proPerties of TGS crystals.
基金supported by the National Natural Science Foundation of China(Grant 52072041)the Beijing Natural Science Foundation(Grant JQ21007)the University of Chinese Academy of Sciences(Grant Y8540XX2D2).
文摘Tactile sensors are a potential solution for material identification.However,current potential tactile sensors for material identification are pressed,expensive,and applications-confined.Here we report a clamped-on pyroelectric tactile sensor on the basis of a ferroelectric Bi_(0.5)Na_(0.5)TiO_(3) material to identify different film materials.The fabricated device exhibits different heat absorption capacities while in contact with different materials,leading to a different temperature change in the ferroelectric material under the same illumination.As a result,the device can recognize different materials by comparing the pyroelectric charge via integrating the obtained current under the same irradiation of 365nmlight-emitting diode.The clamped-on pyroelectric tactile sensor can identify six individual materials with a high accuracy of 98.8%and a fast response of 40 ms.All of the above processes can be accomplished with an intelligent material identification system.The device provides a new solution for material identification and lays a foundation for smart factories and laboratories.
基金supported by the National Natural Science Foundation of China(82072057,82311540023)。
文摘It is desirable but always challenging to develop a cutting-edge tumor treatment strategy with high therapeutic efficacy,lesiontargeted precision and mild accessibility.Compared to traditional treatment modalities,photodynamic therapy has been widely studied since the generation of reactive oxygen species(ROS)at cancerous lesions unprecedentedly offers a convenient approach for localized tumor eliminations.Nevertheless,the consumption of oxygen for ROS production in a hypoxic tumor microenvironment has dramatically limited its feasibility and efficacy.Herein,the engineered nanocomposites of BTO@PDA-ICGHA with photodynamic and pyroelectric performances have been fabricated and applied to the photodynamic-pyroelectric dynamic treatments.The continuing ROS production derived from intracellular oxygen(O_(2))and water(H_(2)O)by laser irradiation contributed to the superb tumor cell apoptosis and significant tumor growth inhibition.Thus,this study has validated a new concept by depositing the engineered nanocomposites at the tumor just like Trojan horses,facilitating ROS release as killers and exerting the NIR-induced cell apoptosis and tumor growth inhibition with high therapeutic efficiency and expectable translational perspectives.
基金This work was financially supported by the Russian Federal Government,state assignments#0040-2019-0019 and#0040-2019-0031。
文摘A comprehensive study and detailed analysis of pyroelectric and electrocaloric effects in relaxor ferroelectrics based on lead magnesium niobate as a promising object for such investigations have been carried out.It was found that even at the maximum values of pyroelectric coefficients the electrocaloric response inextricably linked with the pyroelectric effect does not exceed 1°C in the temperature range from 10 to 60°C under DC electric field up to 60 kV/cm.These conditions are the most demanded for the operation of electrocaloric cooling devices.Vision for the future as to increasing the efficiency of the main elements for such devices is discussed.
基金supported by JSPS KAKENHI(grant nos.23H04862,24K21783,24K17698 and 23K04681)support from the Murata Science and Education Foundation(grant no.M24AN117)The synchrotron radiation experiments were performed at the BL01B1 of SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute(proposal no.2021B1342)。
文摘Macroscopic polarization switching achieved through directional electron transfer or spin crossover(SCO)has attracted considerable attention because of its potential applications in data storage devices,sensors,and energy converters.Here,by substituting the central metal and anion of a reported compound,[Fe(RR-cth)Co(SS-cth)(μ-dhbq)](AsF_(6))_(3),we obtained two dinuclear compounds that crystallize in the polar space group,P2_(1),[Fe(RR-cth)Ga(SS-cth)(μ-dhbq)](X)_(3)(X=AsF_(6)and ClO_(4)).Among them,complex 1(AsF_(6))_(3)exhibited a two-step magnetic transition,including SCO behavior near 50 K and a gradual valence tautomerism(VT)behavior that occurred over a wide temperature range up to at least 250 K.The SCO behavior of complex 1(AsF_(6))_(3)can be triggered by changes in temperature or the application of magnetic fields,leading to a polarization change of approximately 0.5μC cm^(−2).The transition entropy of 55.9 J K^(−1)mol^(−1)during the SCO process was obtained using the Clausius-Clapeyron equation.Contrarily,complex 1(ClO_(4))_(3)only exhibited gradual VT behavior from a low temperature to room temperature.Single-crystal X-ray diffraction,variable-temperature infrared spectroscopy,and pyroelectric measurements confirmed the gradual VT process that occurs over a wide temperature range in both complexes.This study broadens the range of polarization switching molecular systems by replacing the central metal and anion,thereby facilitating the development of multifunctional molecular materials.
基金supported by the Shandong Science and Technology Development Plan(No.GG201809230040)the National Natural Science Foundation of China(Grant Nos.61573202 and 11847135).
文摘A flexible,multi-site tactile and thermal sensor(MTTS)based on polyvinylidene fluoride(resolution 50×50)is reported.It can be used to implement spatial mapping caused by tactile and thermal events and record the two-dimensional motion trajectory of a tracked target object.The output voltage and current signal are recorded as amapping by sensing the external pressure and thermal radiation stimulus,and the response distribution is dynamically observed on the three-dimensional interface.Through the mapping relationship between the established piezoelectric and pyroelectric signals,the piezoelectric component and the pyroelectric component are effectively extracted from the composite signals.The MTTS has a good sensitivity for tactile and thermal detection,and the electrodes have good synchronism.In addition,the signal interference is less than 9.5%and decreases as the pressure decreases after the distance between adjacent sites exceeds 200μm.The integration of MTTS and signal processing units has potential applications in human-machine interaction systems,health status detection and smart assistive devices.
基金supported by the National Key Research and Development Program of China (2017YFA0701301)the National Natural Science Foundation of China (51373161 and51672261)。
文摘2-hydroxynaphthylidene-1′-naphthylamine(HNAN) and –NO_(2) modified HNAN(HNAN-NO_(2)) Schiff base compounds were synthesized and exhibited strong visible light absorption(<650 nm). These compounds were added to poly(vinylidene fluoride-trifluoroethylene)(P(VDF-Tr FE))ferroelectric polymer, obtaining composites with high photoelectric response under visible and infrared light. It was found that the modification of HNAN by the nitro group and the poling of the composites under a high electric field can greatly enhance the photoelectric response of the composites. The composites can generate high photovoltages of 1386 and352.7 mV under irradiation with near-infrared light(915 nm)and green light(532 nm). The mechanism of the photoelectric response of the composites under green light was explored and it was found that the response originates mainly from the coupling effect of the photothermal effect of the Schiff base and the pyroelectric effect of the ferroelectric polymer. The composites, which can be utilized as photodetector materials,are promising for next-generation artificial retina applications and the sensing capability of retina can be extended in a wide wavelength range from visible to infrared light.
基金supported by the Mexican Council of Science and Technology (CONACYT) (Nos.SEPCONACYTCB-2016-01-285030 and 804835)。
文摘Here,we present a study of the effective piezoelectric constant(e_(14_(e)))temperature dependence in strained[111]-oriented zinc-blende quantum wells(QWs)embedded within a semiconductor optical amplifier(SOA).We determined e_(14_(e)) using a method that was insensitive to the segregation phenomenon and to the temperature dependence of the bandgap energy,which required neither fitting parameters nor temperature-dependent expressions for energy and out-of-plane effective masses of electrons and heavy holes.An e_(14_(e))=−0.0534±0.0040 C·m^(−2) at 23°C was obtained for an SOA with 1.2 nm[111]-oriented strained In0.687Ga0.313As/In0.807Ga0.193As0.304P0.696 QWs.Unlike previously published research,where e_(14_(e)) magnitude increased as temperature rised,we extracted an e_(14_(e)) magnitude that decreased as temperature increased.
基金This research was performed into framework of financing RFBR grant number 19-08-00365A.
文摘It has been established that in plates made of hot-pressed ferroelectric ceramics PZT-19(Tc=300℃),after metal electrodes from Ag are burned into opposite surfaces with different depths of mechanical damage,counter-directional stationary deformation gradients and,accordingly,internal electric displacement fields create a stationary flexoelectric effect.As a result,unpolarized ceramics below the Curie temperature become a pyroelectric,and above it become a pyroelectric bolometer.After polishing the less damaged surface and replacing the Ag(valency v=3)electrode with Cr(v=6)by thermal evaporation in vacuum from the intact surface,a new thermally stable polarization is created,directed from the damaged surface in the interelectrode volume.Such plates have an asymmetric dielectric hysteresis loop,retain the values of the pyroelectric effect and piezoelectric effect in the ferroelectric phase,as well as the bolometric effect in the paraelectric phase after repeated heating cycles to 400℃ and cooling to T_(norm).
