A simple layer-by-layer deposition technique was used to fabricate the multilayer thin films of unmodified silver triangular nanoplates （AgTNPs）. The multilayer of AgTNPs thin films were fabricated by alternate depo...A simple layer-by-layer deposition technique was used to fabricate the multilayer thin films of unmodified silver triangular nanoplates （AgTNPs）. The multilayer of AgTNPs thin films were fabricated by alternate deposition of each anionic sodium citrate stabilized AgTNPs and cationic poly（diallyldimethylammonium chloride）. All prepared AgTNPs multilayer thin films were exhibited a strong plasmon band at the wavelength of 667 rim, which confirmed the formation of AgTNPs onto the substrate. The characteristics of the multilayer thin films were investigated using contact angle measurement, UV-visible spectroscopy, X-ray diffraction analysis （XRD）, atomic force microscope （AFM） and field emission scanning electron microscope （FESEM）. As these films are to be used as a mercury （Ⅱ） colorimetric sensor, the changes in optical properties of the films were evaluated for various mercury （Ⅱ） concentrations. AgTNPs assembled into thin films showed a strong color shift from blue to mauve and colorless when exposed to mercury （Ⅱ）. The constructed multilayer thin films exhibited excellent color changes of mercury （Ⅱ） with a linear range between 0.5 and 20 ppm. The limit of detection （LOD） and limit of quantitation （LOQ） were 0.45 ± 0.002 and 1.52 - 0.002 ppm, respectively. The recovery values of AgTNPs multilayer thin films are satisfactory in the range of 100.1%-106.4% when applied to determining mercury （Ⅱ） in water samt）les.展开更多
In the present study, multiwalled carbon nanotubes（MWCNTs）, gold nanoparticles（AuN Ps）, and glutathione（GSH） were used to fabricate multilayer nanoscale thin films. The composite thin films were fabricated by la...In the present study, multiwalled carbon nanotubes（MWCNTs）, gold nanoparticles（AuN Ps）, and glutathione（GSH） were used to fabricate multilayer nanoscale thin films. The composite thin films were fabricated by layer-by-layer technique as the films were constructed by the alternate deposition of cationic and anionic polyelectrolytes. The MWCNTs were modified via a noncovalent surface modification method using poly（diallydimethylammonium chloride） to form a cationic polyelectrolyte. An anionic polyelectrolyte was prepared by the chemical reduction of HAuCl_4 using sodium citrate as both the stabilizing and reducing agent to form anionic AuN Ps. GSH was used as an electrocatalyst toward the electro-oxidation of dopamine. The constructed composite electrode exhibits excellent electrocatalytic activity toward dopamine with a short response time and a wide linear range from 1 to 100 mmol/L. The limits of detection and quantitation of dopamine are（0.316 ± 0.081） mmol/L and（1.054 ± 0.081） mmol/L, respectively. The method is satisfactorily applied for the determination of dopamine in plasma and urine samples to obtain the recovery in the range from 97.90% to 105.00%.展开更多
The tribovoltaic nanogenerator(TVNG)has evolved in recent years as a novel type of nanogenerator designed to address the limitations of the standard triboelectric nanogenerator in terms of output signal and charge gen...The tribovoltaic nanogenerator(TVNG)has evolved in recent years as a novel type of nanogenerator designed to address the limitations of the standard triboelectric nanogenerator in terms of output signal and charge generation.Besides the outstanding characteristics,the tribovoltaic effect can also well be coupled with another effect to further boost the output performance.In this work,we proposed firstly a frictional heat-assisted performance enhancement in dynamic Schottky contact from the rubbing between n-type silver selenide(Ag_(2)Se)and aluminum.The chemical composition and physical characteristics of the Ag_(2)Se ceramic were analyzed using X-ray diffraction,scanning electron microscopy,and Synchrotron X-ray tomography techniques.UVeVis spectroscopy and UPS were also utilized in order to validate the semiconducting property of the n-type Ag_(2)Se ceramic.Moreover,the presence of the Schottky junction was demonstrated through the analysis of the current-bias voltage characteristic curve of the Ag_(2)Se/aluminum(Al)contact under varying stress and temperature conditions.The built-in electric field plays a crucial part in the tribovoltaic effect by efficiently transferring the excited carriers to an external load through sliding contact between Ag_(2)Se and Al.Demonstrating the synergy between tribovoltaic and thermoelectric effects becomes achievable through the excellent thermoelectric property of Ag_(2)Se.Herein,the proposed TVNG generated a peak output voltage and current of around 0.7 V and 24.8 nA,respectively,achieving a maximum output power of 12.6 nW at a load resistance of 10 kU.The influence of frictional heat on the output performance of the proposed TVNG was well demonstrated by the thermal-induced voltage and enhanced electrical output from continuous sliding.The concepts given in this study establish the basis for the progress of effective energy collection employing semiconducting materials and the advancement of flexible harvesting and sensing device development in the future.展开更多
Dielectric materials,such as barium titanate(BT)-based materials,have excellent dielectric properties but require high temperatures(above 1300℃)for ceramic fabrication,leading to high costs and energy loss.The cold s...Dielectric materials,such as barium titanate(BT)-based materials,have excellent dielectric properties but require high temperatures(above 1300℃)for ceramic fabrication,leading to high costs and energy loss.The cold sintering process(CSP)offers a solution to these issues and is gaining worldwide attention as an innovative fabrication route.In this work,we proposed an alternative organic ferroelectric phase,gamma-glycine(γ-GC),which acts as a transient liquid phase to fabricate high-density composites with barium titanate(BT)at low temperatures through CSP.Our findings show that the density of 15γ-GC/85BT reached 96.7%±1.6%when it was sintered at 120℃for 6 h under 10 MPa uniaxial pressure.Scanning electron microscopy‒energy dispersive X-ray spectroscopy(SEM‒EDS)mappings of the composite suggested thatγ-GC completely underwent the precipitation-dissolution process and,therefore,filled between BT particles.Moreover,X-ray diffraction(XRD)and Fourier-transform infrared spectroscopy(FTIR)confirmed the preservation ofγ-GC without undesired phase transformation.In addition,the ferroelectric and dielectric properties ofγ-GC/BT composites have been reported.The high dielectric constant(ε_(r))was 3600,and the low dielectric loss(tanδ)was 1.20 at 200℃and 100 kHz for the 15γ-GC/85BT composite.The hysteresis loop showed a remanent polarization(P_(r))of 0.55µC·cm^(−2)and a coercive field(E_(c))of 7.25 kV·cm^(−1).Our findings reaffirmed that an organic ferroelectric material(γ-GC)can act as a transient liquid phase in a CSP that can successfully and sustainably fabricateγ-GC/BT composites at low temperatures while delivering outstandingly high performance.展开更多
Using combined cooling,heat and power systems can be an appropriate substitute for preventing emissions of pollutants and excessive consumption of fossil fuels.Utilizing renewable energy in these systems as a source o...Using combined cooling,heat and power systems can be an appropriate substitute for preventing emissions of pollutants and excessive consumption of fossil fuels.Utilizing renewable energy in these systems as a source of power generation can be an appropriate substitute for fossil-fuel-based systems.Therefore,in this paper,cogeneration cooling,heat and power systems based on gas-fired internal combustion engines with a solar-thermal system with evacuated tube collectors have been modelled and thermo-economic analysis has been done to compare fossil-fuel-based systems.The required rate of heat to supply the hot water is 50 kW.In the studied system,the internal combustion engine produces electrical energy.Then,the solar-thermal system with evacuated tube collectors and the gas-burning generator provide the thermal energy required by the studied building and the primary stimulus of the absorption chiller for cooling.In this study,two different scenarios are conducted in states considering simultaneous production systems and regardless of this environmental and thermo-economic analysis system.The results showed that the efficiency of the studied system was 60% in summer and 56% in winter.展开更多
To use energy systems based on renewable sources,it is very important to consider backup and hybrid sources because renewable energies are not available all the time;therefore,in this system,a geothermal pump is used ...To use energy systems based on renewable sources,it is very important to consider backup and hybrid sources because renewable energies are not available all the time;therefore,in this system,a geothermal pump is used to preheat the fluid,then the heated fluid is sent to the vacuum tube collector to reach a higher temperature by absorbing solar-thermal energy,and after absorbing solar energy,it goes to the evaporator to produce superheated steam and finally the superheated fluid moves to the steam turbine to produce energy.After the simulation,thermodynamic analysis along with economic analysis has been done.In the base state,the energy efficiency and exergy of cogeneration were 0.566 and 0.156,respectively;the energy efficiency and electrical exergy were better than 0.057 and 0.065;and the overall output and immutable work values were 50 and 671.1 kW,respectively.展开更多
In this study,based on the energy balance for different components of a double-layered vacuum-tube solar collector with a U-tube,the thermal performance of the collector unit is investigated separately using an analyt...In this study,based on the energy balance for different components of a double-layered vacuum-tube solar collector with a U-tube,the thermal performance of the collector unit is investigated separately using an analytical and quasi-dynamic method.The model used in this study determines the temperature distribution in longitudinal and radial directions.In this research,the effects of physical parameters and heat transfer including the size of the collector,thermal-loss coefficient,absorption coefficient,mass flow and thermal resistance of the air layer under different climate conditions have been evaluated on the performance of the vacuum-tube collector.The results showed that by increasing the diameter of the tube with constant length,the annual thermal efficiency of the collector increased.Also,in a fixed-diameter tube,with increasing tube length,the annual efficiency increases,but this increase is meagre for lengths of>1.5 m.The optimal mass flow rate for maximum efficiency has been obtained for cities with different climates.According to the results,the optimal flow for different climates has different values that can be optimized as a relationship between the average solar radiation annually as a symbol of temperature and flow.展开更多
Due to the short distance between the sources of production and consumption,microgrids(MGs)have received considerable attention because these systems involve fewer losses and waste less energy.And another advantage of...Due to the short distance between the sources of production and consumption,microgrids(MGs)have received considerable attention because these systems involve fewer losses and waste less energy.And another advantage of MGs is that renewable energy sources can be widely used because these resources are not fully available and can provide a part of the required power.The purpose of this research is to model the MG considering the production sources of microturbines,gas turbines and internal combustion engines.Renewable energies such as wind turbines(WTs)and photovoltaic(PV)cells have been used to provide part of the required power and,because of the lack of access to renewable energy sources at all times,energy reserves such as batteries and fuel cells(FCs)have been considered.The power of the microturbine,gas turbine,internal combustion engine,FC and battery in this system is 162,150,90,100 and 225 kW,respectively.After modelling the studied system,optimization was done using the imperialist competitive algorithm to minimize production costs and provide maximum thermal and electrical loads.The maximum production power for PVs is equal to 0.6860 MWh and at this time this value for WTs is equal to 0.3812 MWh,in which case the excess electricity produced will be sold to the grid.展开更多
Transparent,flexible,and high-performance triboelectric nanogenerator(TENG)from nature-derived materials are required for sustainable society development.However,low triboelectricity from natural material is generally...Transparent,flexible,and high-performance triboelectric nanogenerator(TENG)from nature-derived materials are required for sustainable society development.However,low triboelectricity from natural material is generally observed.Tunable electronic band diagram(EBD)through facile manipulation is one of the efficient methods to promote the TENG output,requiring fundamental,in depth understanding.Herein,we employed the high quality,single crystal-like Ti_(2)NbO_(7)nanosheets(NSs)with dual dielectric and semiconducting properties as filler for bacterial cellulose(BC)-based TENG.Several techniques including X-ray diffraction(XRD),scanning electron microscopy(SEM),atomic force microscopy(AFM),ultraviolet–visible(UV–vis)absorption,energy dispersive X-ray spectroscopy(EDS),and synchrotron radiation X-ray tomographic microscopy(SRXTM)were applied to characterize the long-range structure,microstructure,optical properties,elemental composition,and three-dimensional(3D)distribution of components in the composites.The semi-transparent and flexible 5 vol.%Ti_(2)NbO_(7)NSs/BC preserved the integrity of cellulose,contained well-dispersed nanosheets,reduced optical band gap(4.20 vs.5.75 eV for BC),and increased surface roughness.The dielectric permittivity and conductivity increased with nanosheets content.Adding negatively-charged Ti_(2)NbO_(7)NSs could regulate the charge affinity of BC composite via shifting of Fermi energy over that of Al.It is found that adding 5 vol.%NSs into the BC film improved electrical outputs(~36 V and~8.8μA),which are 2–4 times higher than that of pure BC,even when paired with Al which lies adjacent in triboelectric series.Our work demonstrated the method to enhance BC-based TENG performance through EBD regulation using multifunctional Ti_(2)NbO_(7)NSs.展开更多
The use of solar energy is highly welcomed due to its availability everywhere.Among the types of solar energy technologies,the use of this type of energy to produce heat from different aspects is much more common,so i...The use of solar energy is highly welcomed due to its availability everywhere.Among the types of solar energy technologies,the use of this type of energy to produce heat from different aspects is much more common,so in this research we have tried to examine different aspects of producing thermal energy from solar energy to supply the heat required by the pool.For this purpose,numerical modelling of the solar pool has been done by considering the heat-transfer characteristics and validation has been done to ensure the obtained results.In this paper,according to the physical realities facing solar systems in two scenarios,an analysis with shadow and without shadow has been done.One of the important results is that as the surface of the pool increases,the amount of heat absorption by the pool fluid will increase,but the effect of the shadow will decrease.展开更多
基金supported by Faculty of Science,King Mongkut's Institute of Technology Ladkrabang,Bangkok,Thailand(No.2559-01-05-033)
文摘A simple layer-by-layer deposition technique was used to fabricate the multilayer thin films of unmodified silver triangular nanoplates （AgTNPs）. The multilayer of AgTNPs thin films were fabricated by alternate deposition of each anionic sodium citrate stabilized AgTNPs and cationic poly（diallyldimethylammonium chloride）. All prepared AgTNPs multilayer thin films were exhibited a strong plasmon band at the wavelength of 667 rim, which confirmed the formation of AgTNPs onto the substrate. The characteristics of the multilayer thin films were investigated using contact angle measurement, UV-visible spectroscopy, X-ray diffraction analysis （XRD）, atomic force microscope （AFM） and field emission scanning electron microscope （FESEM）. As these films are to be used as a mercury （Ⅱ） colorimetric sensor, the changes in optical properties of the films were evaluated for various mercury （Ⅱ） concentrations. AgTNPs assembled into thin films showed a strong color shift from blue to mauve and colorless when exposed to mercury （Ⅱ）. The constructed multilayer thin films exhibited excellent color changes of mercury （Ⅱ） with a linear range between 0.5 and 20 ppm. The limit of detection （LOD） and limit of quantitation （LOQ） were 0.45 ± 0.002 and 1.52 - 0.002 ppm, respectively. The recovery values of AgTNPs multilayer thin films are satisfactory in the range of 100.1%-106.4% when applied to determining mercury （Ⅱ） in water samt）les.
基金financially supported by the Faculty of Science,King Mongkut’s Institute of Technology Ladkrabang,Bangkok,Thailand(No.2558-02050067)
文摘In the present study, multiwalled carbon nanotubes（MWCNTs）, gold nanoparticles（AuN Ps）, and glutathione（GSH） were used to fabricate multilayer nanoscale thin films. The composite thin films were fabricated by layer-by-layer technique as the films were constructed by the alternate deposition of cationic and anionic polyelectrolytes. The MWCNTs were modified via a noncovalent surface modification method using poly（diallydimethylammonium chloride） to form a cationic polyelectrolyte. An anionic polyelectrolyte was prepared by the chemical reduction of HAuCl_4 using sodium citrate as both the stabilizing and reducing agent to form anionic AuN Ps. GSH was used as an electrocatalyst toward the electro-oxidation of dopamine. The constructed composite electrode exhibits excellent electrocatalytic activity toward dopamine with a short response time and a wide linear range from 1 to 100 mmol/L. The limits of detection and quantitation of dopamine are（0.316 ± 0.081） mmol/L and（1.054 ± 0.081） mmol/L, respectively. The method is satisfactorily applied for the determination of dopamine in plasma and urine samples to obtain the recovery in the range from 97.90% to 105.00%.
基金funded by King Mongkut’s University of Technology North Bangkok,Contract no.KMUTNB-67-KNOW-02by National Science,Research and Innovation Fund(NSRF)+1 种基金King Mongkut’s University of Technology North Bangkok(Project no.KMUTNBeFFe67-B-35)supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)(2021R1C1C1011588).
文摘The tribovoltaic nanogenerator(TVNG)has evolved in recent years as a novel type of nanogenerator designed to address the limitations of the standard triboelectric nanogenerator in terms of output signal and charge generation.Besides the outstanding characteristics,the tribovoltaic effect can also well be coupled with another effect to further boost the output performance.In this work,we proposed firstly a frictional heat-assisted performance enhancement in dynamic Schottky contact from the rubbing between n-type silver selenide(Ag_(2)Se)and aluminum.The chemical composition and physical characteristics of the Ag_(2)Se ceramic were analyzed using X-ray diffraction,scanning electron microscopy,and Synchrotron X-ray tomography techniques.UVeVis spectroscopy and UPS were also utilized in order to validate the semiconducting property of the n-type Ag_(2)Se ceramic.Moreover,the presence of the Schottky junction was demonstrated through the analysis of the current-bias voltage characteristic curve of the Ag_(2)Se/aluminum(Al)contact under varying stress and temperature conditions.The built-in electric field plays a crucial part in the tribovoltaic effect by efficiently transferring the excited carriers to an external load through sliding contact between Ag_(2)Se and Al.Demonstrating the synergy between tribovoltaic and thermoelectric effects becomes achievable through the excellent thermoelectric property of Ag_(2)Se.Herein,the proposed TVNG generated a peak output voltage and current of around 0.7 V and 24.8 nA,respectively,achieving a maximum output power of 12.6 nW at a load resistance of 10 kU.The influence of frictional heat on the output performance of the proposed TVNG was well demonstrated by the thermal-induced voltage and enhanced electrical output from continuous sliding.The concepts given in this study establish the basis for the progress of effective energy collection employing semiconducting materials and the advancement of flexible harvesting and sensing device development in the future.
基金supported by King Mongkut’s Institute of Technology Ladkrabang(KMITL)under Grant Nos.KREF116501 and 2567-02-05-020funded by Grant No.KREF016412+2 种基金supported by the National Research Council of Thailand(NRCT)through Grant No.N42A650220support from the School of Science at KMITL.T.Bongkarn acknowledges financial assistance from Naresuan University,the National Science,Research,and Innovation Fund(NSRF)under Grant No.R2567B001the Global and Frontier Research University Fund at Naresuan University(NU)under Grant No.R2567C001.
文摘Dielectric materials,such as barium titanate(BT)-based materials,have excellent dielectric properties but require high temperatures(above 1300℃)for ceramic fabrication,leading to high costs and energy loss.The cold sintering process(CSP)offers a solution to these issues and is gaining worldwide attention as an innovative fabrication route.In this work,we proposed an alternative organic ferroelectric phase,gamma-glycine(γ-GC),which acts as a transient liquid phase to fabricate high-density composites with barium titanate(BT)at low temperatures through CSP.Our findings show that the density of 15γ-GC/85BT reached 96.7%±1.6%when it was sintered at 120℃for 6 h under 10 MPa uniaxial pressure.Scanning electron microscopy‒energy dispersive X-ray spectroscopy(SEM‒EDS)mappings of the composite suggested thatγ-GC completely underwent the precipitation-dissolution process and,therefore,filled between BT particles.Moreover,X-ray diffraction(XRD)and Fourier-transform infrared spectroscopy(FTIR)confirmed the preservation ofγ-GC without undesired phase transformation.In addition,the ferroelectric and dielectric properties ofγ-GC/BT composites have been reported.The high dielectric constant(ε_(r))was 3600,and the low dielectric loss(tanδ)was 1.20 at 200℃and 100 kHz for the 15γ-GC/85BT composite.The hysteresis loop showed a remanent polarization(P_(r))of 0.55µC·cm^(−2)and a coercive field(E_(c))of 7.25 kV·cm^(−1).Our findings reaffirmed that an organic ferroelectric material(γ-GC)can act as a transient liquid phase in a CSP that can successfully and sustainably fabricateγ-GC/BT composites at low temperatures while delivering outstandingly high performance.
文摘Using combined cooling,heat and power systems can be an appropriate substitute for preventing emissions of pollutants and excessive consumption of fossil fuels.Utilizing renewable energy in these systems as a source of power generation can be an appropriate substitute for fossil-fuel-based systems.Therefore,in this paper,cogeneration cooling,heat and power systems based on gas-fired internal combustion engines with a solar-thermal system with evacuated tube collectors have been modelled and thermo-economic analysis has been done to compare fossil-fuel-based systems.The required rate of heat to supply the hot water is 50 kW.In the studied system,the internal combustion engine produces electrical energy.Then,the solar-thermal system with evacuated tube collectors and the gas-burning generator provide the thermal energy required by the studied building and the primary stimulus of the absorption chiller for cooling.In this study,two different scenarios are conducted in states considering simultaneous production systems and regardless of this environmental and thermo-economic analysis system.The results showed that the efficiency of the studied system was 60% in summer and 56% in winter.
基金The authors would like to express their gratitude to the Al-Mustaqbal University college for the support of the project.
文摘To use energy systems based on renewable sources,it is very important to consider backup and hybrid sources because renewable energies are not available all the time;therefore,in this system,a geothermal pump is used to preheat the fluid,then the heated fluid is sent to the vacuum tube collector to reach a higher temperature by absorbing solar-thermal energy,and after absorbing solar energy,it goes to the evaporator to produce superheated steam and finally the superheated fluid moves to the steam turbine to produce energy.After the simulation,thermodynamic analysis along with economic analysis has been done.In the base state,the energy efficiency and exergy of cogeneration were 0.566 and 0.156,respectively;the energy efficiency and electrical exergy were better than 0.057 and 0.065;and the overall output and immutable work values were 50 and 671.1 kW,respectively.
文摘In this study,based on the energy balance for different components of a double-layered vacuum-tube solar collector with a U-tube,the thermal performance of the collector unit is investigated separately using an analytical and quasi-dynamic method.The model used in this study determines the temperature distribution in longitudinal and radial directions.In this research,the effects of physical parameters and heat transfer including the size of the collector,thermal-loss coefficient,absorption coefficient,mass flow and thermal resistance of the air layer under different climate conditions have been evaluated on the performance of the vacuum-tube collector.The results showed that by increasing the diameter of the tube with constant length,the annual thermal efficiency of the collector increased.Also,in a fixed-diameter tube,with increasing tube length,the annual efficiency increases,but this increase is meagre for lengths of>1.5 m.The optimal mass flow rate for maximum efficiency has been obtained for cities with different climates.According to the results,the optimal flow for different climates has different values that can be optimized as a relationship between the average solar radiation annually as a symbol of temperature and flow.
文摘Due to the short distance between the sources of production and consumption,microgrids(MGs)have received considerable attention because these systems involve fewer losses and waste less energy.And another advantage of MGs is that renewable energy sources can be widely used because these resources are not fully available and can provide a part of the required power.The purpose of this research is to model the MG considering the production sources of microturbines,gas turbines and internal combustion engines.Renewable energies such as wind turbines(WTs)and photovoltaic(PV)cells have been used to provide part of the required power and,because of the lack of access to renewable energy sources at all times,energy reserves such as batteries and fuel cells(FCs)have been considered.The power of the microturbine,gas turbine,internal combustion engine,FC and battery in this system is 162,150,90,100 and 225 kW,respectively.After modelling the studied system,optimization was done using the imperialist competitive algorithm to minimize production costs and provide maximum thermal and electrical loads.The maximum production power for PVs is equal to 0.6860 MWh and at this time this value for WTs is equal to 0.3812 MWh,in which case the excess electricity produced will be sold to the grid.
基金funded by the Office of the Permanent Secretary,Ministry of Higher Education,Science,Research and Innovation(OPS MHESI),Thailand Science Research and Innovation(TSRI)and King Mongkut’s University of Technology North Bangkok(No.RGNS 63-233),and the Faculty of Science,Energy and Environment,King Mongkut’s University of Technology North Bangkok(No.SCIEE-KMUTNB-64-002)funded by the King Mongkut’s Institute of Technology Ladkrabang(KMITL)(No.KREF116501)supported by the OPS MHESI,TSRI and Srinakharinwirot University(No.RGNS 64-211).
文摘Transparent,flexible,and high-performance triboelectric nanogenerator(TENG)from nature-derived materials are required for sustainable society development.However,low triboelectricity from natural material is generally observed.Tunable electronic band diagram(EBD)through facile manipulation is one of the efficient methods to promote the TENG output,requiring fundamental,in depth understanding.Herein,we employed the high quality,single crystal-like Ti_(2)NbO_(7)nanosheets(NSs)with dual dielectric and semiconducting properties as filler for bacterial cellulose(BC)-based TENG.Several techniques including X-ray diffraction(XRD),scanning electron microscopy(SEM),atomic force microscopy(AFM),ultraviolet–visible(UV–vis)absorption,energy dispersive X-ray spectroscopy(EDS),and synchrotron radiation X-ray tomographic microscopy(SRXTM)were applied to characterize the long-range structure,microstructure,optical properties,elemental composition,and three-dimensional(3D)distribution of components in the composites.The semi-transparent and flexible 5 vol.%Ti_(2)NbO_(7)NSs/BC preserved the integrity of cellulose,contained well-dispersed nanosheets,reduced optical band gap(4.20 vs.5.75 eV for BC),and increased surface roughness.The dielectric permittivity and conductivity increased with nanosheets content.Adding negatively-charged Ti_(2)NbO_(7)NSs could regulate the charge affinity of BC composite via shifting of Fermi energy over that of Al.It is found that adding 5 vol.%NSs into the BC film improved electrical outputs(~36 V and~8.8μA),which are 2–4 times higher than that of pure BC,even when paired with Al which lies adjacent in triboelectric series.Our work demonstrated the method to enhance BC-based TENG performance through EBD regulation using multifunctional Ti_(2)NbO_(7)NSs.
文摘The use of solar energy is highly welcomed due to its availability everywhere.Among the types of solar energy technologies,the use of this type of energy to produce heat from different aspects is much more common,so in this research we have tried to examine different aspects of producing thermal energy from solar energy to supply the heat required by the pool.For this purpose,numerical modelling of the solar pool has been done by considering the heat-transfer characteristics and validation has been done to ensure the obtained results.In this paper,according to the physical realities facing solar systems in two scenarios,an analysis with shadow and without shadow has been done.One of the important results is that as the surface of the pool increases,the amount of heat absorption by the pool fluid will increase,but the effect of the shadow will decrease.
