As one of the most appealing and attractive technologies, photocatalysis is widely used as a promising method to circumvent the environmental and energy problems. Due to its chemical stability and unique physicochemic...As one of the most appealing and attractive technologies, photocatalysis is widely used as a promising method to circumvent the environmental and energy problems. Due to its chemical stability and unique physicochemical, graphitic carbon nitride (g-C3N4) has become research hotspots in the community. However, g-C3N4 photocatalyst still suffers from many problems, resulting in unsatisfactory photocatalytic activity such as low specific surface area, high charge recombination and insufficient visible light utilization. Since 2009, g-C3N4-based heterostructures have attracted the attention of scientists worldwide for their greatly enhanced photocatalytic performance. Overall, this review summarizes the recent advances of g-C3N4-based nanocomposites modified with transition metal sulfide (TMS), including (1) preparation of pristine g-C3N4,(2) modification strategies of g-C3N4,(3) design principles of TMS-modified g-C3N4 heterostructured photocatalysts, and (4) applications in energy conversion. What is more, the characteristics and transfer mechanisms of each classification of the metal sulfide heterojunction system will be critically reviewed, spanning from the following categories:(1) Type I heterojunction,(2) Type II heterojunction,(3) p-n heterojunction,(4) Schottky junction and (5) Z-scheme heterojunction. Apart from that, the application of g-C3N4-based heterostructured photocatalysts in H2 evolution, CO2 reduction, N2 fixation and pollutant degradation will also be systematically presented. Last but not least, this review will conclude with invigorating perspectives, limitations and prospects for further advancing g-C3N4-based heterostructured photocatalysts toward practical benefits for a sustainable future.展开更多
The microstructure and electrical properties of ZnO-Bi2O3-Yb2O3 based varistor ceramics were investigated with various temperature effects from 900°C to 1050°C.From the results,it was observed that the incre...The microstructure and electrical properties of ZnO-Bi2O3-Yb2O3 based varistor ceramics were investigated with various temperature effects from 900°C to 1050°C.From the results,it was observed that the increase of sintering temperature offers a reduced capacitive effect from 0.460 nF to 0.321 nF.Furthermore,the grain sizes of varistors were varied from 6.8μm to 9.8μm.The consequence of such smaller grain sizes provided a better voltage gradient of about 895 V/mm for the disc sintered at 900°C and fallen drastically to 410 V/mm for the sample sintered at 1050°C.In addition,there was an increase of non-linearity index to a maximum value of 36.0 and reduced leakage current of 0.026 mA/cm2.However,the density of the varistor decreased with an increase of temperature from 5.41 g/cm3 to 5.24 g/cm3.With this base,the influence of varistor capacitance and high voltage gradient were scrutinized and it led an improved transition speed of the varistor assembly from non-conduction to conduction mode during intruding nanosecond transients.展开更多
A new configuration integrated ion exchange effect with both electro-migration and electrochemical reaction in a single cell was developed to effectively retrieve metal ions from simulated wastewater using ion exchang...A new configuration integrated ion exchange effect with both electro-migration and electrochemical reaction in a single cell was developed to effectively retrieve metal ions from simulated wastewater using ion exchange resins without additive chemicals. By simply assembling cation exchange resins and anion exchange resins separated by homogeneous membranes, we found that the system will always be acidic in the concentrate compartment so that ion exchange resins could be in-situ regenerated without hydroxide precipitation. Such a realizable design will be really suitable for wastewater purification.展开更多
Solar‐to‐chemical energy conversion is perceived as one of the most potential solutions to the current energy and environmental crisis,yet requires major scientific endeavors on the development of efficient and sust...Solar‐to‐chemical energy conversion is perceived as one of the most potential solutions to the current energy and environmental crisis,yet requires major scientific endeavors on the development of efficient and sustainable photocatalysts.Remolding the composition and morphology of a semiconductor jointly for the purpose of improving photocatalysis efficiency remains challenging.Herein,we rationally fabricated Cu‐doped ZnS nanoframes via a simple conjunct strategy of substitutional doping,chemical acidic etching,and sulfidation,aiming at enhancing the light utilization and charge separation/transfer efficiency for solar‐light‐driven hydrogen generation.Cu‐doped zeolitic imidazolate framework‐8(ZIF‐8)rhombic dodecahedrons are transformed to hollow Cu‐ZIF‐8 nanoframes converted to Cu‐ZnS nanoframes with three‐dimensional photocatalytic active surfaces via anisotropic chemical etching,which is further converted to Cu‐ZnS nanoframes.By combining the merits of optimal heteroatom doping and frame‐like open architecture,the obtained 1%Cu‐doped ZnS nanoframe exhibits high photocatalytic activity under solar light irradiation with improved hydrogen production rate up to 8.30 mmol h^(–1) g^(–1) and excellent stability in the absence of cocatalysts,which is significantly improved in comparison with those of the bare ZnS and Cu‐ZnS with different morphologies.This work inspired by merging the merits of metal doping and anisotropic chemical etching may shed light on the rational design and fabrication of advanced photocatalysts.展开更多
The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen e...The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen electrolytic cell equipped with an electrostatic-induction potential-superposed water electrolytic cell that provides a stoichiometric H2-O2 fuel mixture during operation of the vehicle. This generator functions with zero power input, zero matter input and zero emission due to the so-called "zero power input" electrostatic-to-chemical energy conversion occurring in the electrolytic cell. Here, theoretical simulations were performed to verify the target performance of such generators, assuming a pair of FC (fuel cell) and electrolytic cell stacks, both of which are commercially available.展开更多
Transparent oxyfluoride silicate precursor glasses and glass ceramics with the novel composition (1) SiO2-PbO-PbFE-Er2O3, (2) SiO2-GeOE-PbO-PbFE-Er2O3 (3) SiO2-Al2O3-Y2O3-Na2O-NaF-LiF-Er2O3-YbF3 doped with Er^3...Transparent oxyfluoride silicate precursor glasses and glass ceramics with the novel composition (1) SiO2-PbO-PbFE-Er2O3, (2) SiO2-GeOE-PbO-PbFE-Er2O3 (3) SiO2-Al2O3-Y2O3-Na2O-NaF-LiF-Er2O3-YbF3 doped with Er^3+ and co-doped with Er^3+/Yb^3+ ions were synthesized. X-ray diffraction analysis (XRD) and Er3+ absorption spectra revealed precipitation of PbF2 nanocrystals dispersed in the glassy matrix. Under 980 nm laser excitation, intense green, red and near IR bands of upconversion luminescence (UCL) were recorded both before and after heat treatment. In the glass ceramics the upconversion intensity increased significantly. To our knowledge, for the first time the composition of the glass ceramics characterized by the small-angle neutron scattering (SANS) showed the cluster organization of PbF2 nanocrystals.展开更多
A novel level-shift LDMOS (lateral double-diffused metal oxide semiconductor) structure with the HV (high voltage) -interconnection for a 600 V-HVIC (high voltage integrated circuit) on thick SOI (silicon on in...A novel level-shift LDMOS (lateral double-diffused metal oxide semiconductor) structure with the HV (high voltage) -interconnection for a 600 V-HVIC (high voltage integrated circuit) on thick SOI (silicon on insulator) is proposed. There are two original points in the proposed structure. One is the formation of the double floating p-layers under the HV-interconnection to prevent potential distribution in the drift from disturbing due to the HV-interconnection, and the other is a good combination between the LDMOS structure and multiple trench isolation to obtain the isolation performance over 600 V. From the proposed structure, the high blocking capability of the LDMOS, including both off- and on-breakdown voltages over 600 V and high hot carrier instability, and the isolation performance over 1,200 V can be obtained successfully. This paper will show numerical and experimental results in detail.展开更多
The use of CO2-free energy sources for running SOEC (solid-oxide electrolysis cell) technologies has a great potential to reduce the carbon dioxide emissions compared to fossil fuel based technologies for hydrogen p...The use of CO2-free energy sources for running SOEC (solid-oxide electrolysis cell) technologies has a great potential to reduce the carbon dioxide emissions compared to fossil fuel based technologies for hydrogen production. The operation of the electrolysis cell at higher temperature offers the benefit of increasing the efficiency of the process. The range of the operating temperature of the SOEC is typically between 800 ~C and 1,000 ~C. Main sources of degradation that affect the SOEC stack lifetime is related to the high operating temperature. To increase the electrolyser durability, one possible solution is to decrease the operating temperature down to 650 ~C, which represents the typical operating range of the ITSE (intermediate temperature steam electrolysis). This paper is related to the work of the JU-FCH project ADEL, which investigates different carbon-free energy sources with respect to potential coupling schemes to ITSE. A predominant focus of the analysis is put on solar concentrating energy systems (solar tower) and nuclear energy as energy sources to provide the required electricity and heat for the ITSE. This study will present an overview of the main considerations, the boundary conditions and the results concerning the development of coupling schemes of the energy conversion technologies to the electrolyser.展开更多
Efficiency and power loss in the microelectronic devices is a major issue in power electronics applications. The engineers are challenged every year to increase power density and at the same time reduce the amount of ...Efficiency and power loss in the microelectronic devices is a major issue in power electronics applications. The engineers are challenged every year to increase power density and at the same time reduce the amount of power dissipated in the applications to keep the maximum temperatures under specifications. This situation drives a constant demand for better efficiencies in smaller packages. Traditional approaches to improve efficiency in DC/DC synchronous buck converters include reducing conduction losses in the MOSFETs (metal oxide semiconductor field effect transistors) through lower RDS (ON) (resistance drain to source in the ON state) devices and lowering switching losses through low-frequency operation. However, the incremental improvements in RDS (ON) are at a point of diminishing returns and low RDS (ON) devices have large parasitic capacitances that do not facilitate the high-frequency operation required to improve power density. The drive for higher efficiency and increased power in smaller packages is being addressed by advancements in both silicon and packaging technologies. The NexFET power block combines these two technologies to achieve higher levels of performance, and in half the space versus discrete MOSFETs. This article explains these new technologies and highlights their performance advantage.展开更多
The effects of chenodeoxycholic acid (CDCA) in a dye solution as a co-adsorbent on the photovoltaic performance of dye-sensitized solar cells (DSSCs) based on two organic dyes containing phenothiazine and triarylamine...The effects of chenodeoxycholic acid (CDCA) in a dye solution as a co-adsorbent on the photovoltaic performance of dye-sensitized solar cells (DSSCs) based on two organic dyes containing phenothiazine and triarylamine segments (P1 and P2) were investigated.It was found that the coadsorption of CDCA can hinder the formation of dye aggregates and improve electron injection yield and thus Jsc.This has also led to a rise in photovoltage,which is attributed to the decrease of charge recombination.The DSSC based on dye P2 showed better photovoltaic performance than P1:a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 89.5%,a short-circuit photocurrent density (Jsc) of 9.57 mA/cm2,an open-circuit photovoltage (Voc) of 697 mV,and a fill factor (FF) of 0.66,corresponding to an overall conversion efficiency of 4.42% under the standard global AM 1.5 solar light condition.The overall conversion efficiency was further improved to 5.31% (Jsc=10.36 mA/cm2,Voc=0.730 V,FF=0.70) upon addition of 10 mM CDCA to the dye solution for TiO2 sensitization.Electrochemical impedance data indicate that the electron lifetime was improved by coadsorption of CDCA,accounting for the significant improvement of Voc.These results suggest that interfacial engineering of the organic dye-sensitized TiO2 electrodes is important for highly efficient photovoltaic performance of the solar cell.展开更多
The catalytic effect of electrode materials is one of the most crucial factors for achieving efficient electrochemical energy conversion and storage.Carbon-based metal composites were widely synthesized and employed a...The catalytic effect of electrode materials is one of the most crucial factors for achieving efficient electrochemical energy conversion and storage.Carbon-based metal composites were widely synthesized and employed as electrode materials because of their inherited outstanding properties.Usually,electrode materials can provide a higher capacity than the anticipated values,even beyond the theoretical limit.The origin of the extra capacity has not yet been explained accurately,and its formation mechanism is still ambiguous.Herein,we first summarized the current research progress and drawbacks in energy storage devices(ESDs),and elaborated the role of catalytic effect in enhancing the performance of ESDs as follows:promoting the evolution of the solid electrolyte interphase(SEI),accelerating the reversible conversion of discharge/charge products,and improving the conversion speed of the intermediate and the utilization rate of the active materials,thereby avoiding the shuttling effect.Additionally,a particular focus was placed on the interaction between the catalytic effect and energy storage performance in order to highlight the efficacy and role of the catalytic effect.We hope that this review could provide innovative ideas for designing the electrode materials with an efficient catalytic effect for ESDs to promote the development of this research field.展开更多
Realizing personalized medicine requires integrating diverse data types with bioinformatics.The most vital data are genomic information for individuals that are from advanced next-generation sequencing(NGS) technologi...Realizing personalized medicine requires integrating diverse data types with bioinformatics.The most vital data are genomic information for individuals that are from advanced next-generation sequencing(NGS) technologies at present.The technologies continue to advance in terms of both decreasing cost and sequencing speed with concomitant increase in the amount and complexity of the data.The prodigious data together with the requisite computational pipelines for data analysis and interpretation are stressors to IT infrastructure and the scientists conducting the work alike.Bioinformatics is increasingly becoming the rate-limiting step with numerous challenges to be overcome for translating NGS data for personalized medicine.We review some key bioinformatics tasks,issues,and challenges in contexts of IT requirements,data quality,analysis tools and pipelines,and validation of biomarkers.展开更多
Simultaneous multi-element extraction has been increasing worldwide to improve soil laboratory testing quality and efficiency. This study sought to investigate the applicability of the Mehlich-1, Mehlich-3, and resin ...Simultaneous multi-element extraction has been increasing worldwide to improve soil laboratory testing quality and efficiency. This study sought to investigate the applicability of the Mehlich-1, Mehlich-3, and resin methods for simultaneous extraction of soil available P, K, Ca, and Mg as well as the effect of using conversion equations on nutrient recommendations for crops. Topsoil (0-20 cm) samples were taken from the most representative soil types used for crop production in southern Brazil with a wide range of chemical, physical, and mineralogical properties. Soil P, K, Ca, and Mg were simultaneously extracted using 1.0 mol L-1 KCl, Mehlich-1 and Mehlich-3 solutions, and membrane resin. The amounts of P extracted with the Mehlich-1 method were, on average, 50% lower than those extracted with the resin and Mehlich-3 methods. However, the resin method extracted the lowest amounts of K, Ca, and Mg. The use of conversion equations was suitable and it did not affect negatively the K recommendations for crops grown on soils of southern Brazil.展开更多
The COVID-19 pandemic encouraged the use of plastic-based personal protective equipment (PPE), which aidedgreatly in its management. However, the increased production and usage of these PPEs put a strain on the enviro...The COVID-19 pandemic encouraged the use of plastic-based personal protective equipment (PPE), which aidedgreatly in its management. However, the increased production and usage of these PPEs put a strain on the environment,especially in developing and underdeveloped countries. This has led various researchers to study low-costand effective technologies for the recycling of these materials. One such material is disposable facemasks. However,previous studies have only been able to engage electrically powered reactors for their thermochemical conversion,which is a challenge as these reactors cannot be used in regions with an insufficient supply of electricity. In thisstudy, the authors utilized a biomass-powered reactor for the conversion of waste disposable facemasks and almondleaves into hybrid biochar. The reactor, which is relatively cheap, simple to use, environmentally friendly, and modifiedfor biochar production, is biomass-powered. The co-carbonization process, which lasted 100 min, produced a 46%biochar yield, which is higher than previously obtained biochar yields by other researchers. The biochar thus obtainedwas characterized to determine its properties. FTIR analysis showed that the biochar contained functional groupssuch as alkenes, alkynes, hydroxyls, amines, and carbonyls. The EDX analysis revealed that the biochar was primarilymade of carbon, tellurium, oxygen, and calcium in the ratios of 57%, 19%, 9%, and 7%, respectively. The inclusion ofthe facemask decreased the surface area and porosity of the biochar material, as evidenced by its surface area andpore characteristics.展开更多
Plastic thermo-electrochemical ceils (thermocells) involving aqueous potassium ferricyanide/ferrocyanide electrolyte have been investigated as an alternative to conventional thermoelectrics for thermal energy harves...Plastic thermo-electrochemical ceils (thermocells) involving aqueous potassium ferricyanide/ferrocyanide electrolyte have been investigated as an alternative to conventional thermoelectrics for thermal energy harvesting. Plastic thermocells that consist of all pliable materials such as polyethylene terephthalate (PET), fabrics, and wires are flexible enough to be wearable on the human body and to be wrapped around cylindrical shapes. The performance of the thermocells is enhanced by incorporating carbon nanotubes into activated carbon textiles, due to improved charge transfer at the interface. In cold weather conditions (a surrounding temperature of 5 ℃), the thermocell generates a short-circuit current density of 0.39 A/m2 and maximum power density of 0.46 mW/m2 from body heat (temperature of 36℃). For practical use, we have shown that the thermocell charges up a capacitor when worn on a T-shirt by a person. We also have demonstrated that the electrical energy generated from waste pipe heat using a serial array of the thermocells and voltage converters can power a typical commercial light emitting diode (LED).展开更多
Small molecule organic solar cells (OSCs) with the structure of indium tin oxide (1TO)/molybdenum trioxide (MOO3) (5 nm)/rubrene (x nm)/fullerene (C70) (y nm)/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthro...Small molecule organic solar cells (OSCs) with the structure of indium tin oxide (1TO)/molybdenum trioxide (MOO3) (5 nm)/rubrene (x nm)/fullerene (C70) (y nm)/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP) (6 nm)/aluminum (A1) (150 nm) are fabricated. The thickness of active layer for the devices is investigated in details. The results show that the optimum thicknesses of rubrene layer and C70 layer are 30 nm and 25 nm, respectively. The degradation of the device is also investigated. The result indicates that the open-circuit voltage (Voo) does not change, while the short-circuit current density (Jsc), fill factor (FF) and power conversion efficiency (PCE) decrease continuously with time. The degradation can be attributed to the oxygen in ambient diffusing and infiltrating into the active materials and reacting with C70 in cells, which can result in the increase of interfacial series resistance.展开更多
To study the ferroelectric photovoltaic effect based on polycrystalline films, preparation of high-quality polycrystalline films with low leakage and high remnant polarization is essential. Polycrystalline BiFeO3 (BF...To study the ferroelectric photovoltaic effect based on polycrystalline films, preparation of high-quality polycrystalline films with low leakage and high remnant polarization is essential. Polycrystalline BiFeO3 (BFO) thin films with extremely large remnant polarization (2Pr = 180 ~aC/cm2) were successfully deposited on glass substrates coated with indium tin oxide using a modified radio frequency magnetron sputtering method. Symmetric and asymmetric cells were constructed to investigate the ferroelectric photovoltaic effect in order to understand the relationship between polarization and photovoltaic response. All examined cells showed polarization-induced photovoltaic effect. Our findings also showed that the ferroelectric photovoltaic effect is highly dependent on the material used for the top electrode and the thickness of the polycrystalline film.展开更多
Nonradiative recombination losses at defects in metal halide perovskite films are responsible for hindering the improvement of the photovoltaic performance and stability of perovskite solar cells(PSCs).Here,we report ...Nonradiative recombination losses at defects in metal halide perovskite films are responsible for hindering the improvement of the photovoltaic performance and stability of perovskite solar cells(PSCs).Here,we report a feasible multifunctional additive strategy that uses cesium stearate to passivate defects in perovskite films and simultaneously enhances the tolerance to light and moisture stress.Nonradiative recombination losses are effectively suppressed in target films that exhibit improved crystallinity,low trap-state density,and enhanced carrier separation and transportation.The present strategy hence boosts the power conversion efficiency of the pi-n structured PSC to 23.41%.Our device also shows good stability in ambient air without encapsulation,maintaining 91.6%of the initial efficiency after 720 h.展开更多
基金supported by Xiamen University Malaysia Research Fund (XMUMRF/2019-C3/IENG/0013)financial assistance and faculty start-up grants/supports from Xiamen University~~
文摘As one of the most appealing and attractive technologies, photocatalysis is widely used as a promising method to circumvent the environmental and energy problems. Due to its chemical stability and unique physicochemical, graphitic carbon nitride (g-C3N4) has become research hotspots in the community. However, g-C3N4 photocatalyst still suffers from many problems, resulting in unsatisfactory photocatalytic activity such as low specific surface area, high charge recombination and insufficient visible light utilization. Since 2009, g-C3N4-based heterostructures have attracted the attention of scientists worldwide for their greatly enhanced photocatalytic performance. Overall, this review summarizes the recent advances of g-C3N4-based nanocomposites modified with transition metal sulfide (TMS), including (1) preparation of pristine g-C3N4,(2) modification strategies of g-C3N4,(3) design principles of TMS-modified g-C3N4 heterostructured photocatalysts, and (4) applications in energy conversion. What is more, the characteristics and transfer mechanisms of each classification of the metal sulfide heterojunction system will be critically reviewed, spanning from the following categories:(1) Type I heterojunction,(2) Type II heterojunction,(3) p-n heterojunction,(4) Schottky junction and (5) Z-scheme heterojunction. Apart from that, the application of g-C3N4-based heterostructured photocatalysts in H2 evolution, CO2 reduction, N2 fixation and pollutant degradation will also be systematically presented. Last but not least, this review will conclude with invigorating perspectives, limitations and prospects for further advancing g-C3N4-based heterostructured photocatalysts toward practical benefits for a sustainable future.
文摘The microstructure and electrical properties of ZnO-Bi2O3-Yb2O3 based varistor ceramics were investigated with various temperature effects from 900°C to 1050°C.From the results,it was observed that the increase of sintering temperature offers a reduced capacitive effect from 0.460 nF to 0.321 nF.Furthermore,the grain sizes of varistors were varied from 6.8μm to 9.8μm.The consequence of such smaller grain sizes provided a better voltage gradient of about 895 V/mm for the disc sintered at 900°C and fallen drastically to 410 V/mm for the sample sintered at 1050°C.In addition,there was an increase of non-linearity index to a maximum value of 36.0 and reduced leakage current of 0.026 mA/cm2.However,the density of the varistor decreased with an increase of temperature from 5.41 g/cm3 to 5.24 g/cm3.With this base,the influence of varistor capacitance and high voltage gradient were scrutinized and it led an improved transition speed of the varistor assembly from non-conduction to conduction mode during intruding nanosecond transients.
基金Project supported by the Scientific Research Foundation for theReturned Overseas Chinese Scholars, State Education Ministry andZhejiang Provincial National Science Foundation of China
文摘A new configuration integrated ion exchange effect with both electro-migration and electrochemical reaction in a single cell was developed to effectively retrieve metal ions from simulated wastewater using ion exchange resins without additive chemicals. By simply assembling cation exchange resins and anion exchange resins separated by homogeneous membranes, we found that the system will always be acidic in the concentrate compartment so that ion exchange resins could be in-situ regenerated without hydroxide precipitation. Such a realizable design will be really suitable for wastewater purification.
文摘Solar‐to‐chemical energy conversion is perceived as one of the most potential solutions to the current energy and environmental crisis,yet requires major scientific endeavors on the development of efficient and sustainable photocatalysts.Remolding the composition and morphology of a semiconductor jointly for the purpose of improving photocatalysis efficiency remains challenging.Herein,we rationally fabricated Cu‐doped ZnS nanoframes via a simple conjunct strategy of substitutional doping,chemical acidic etching,and sulfidation,aiming at enhancing the light utilization and charge separation/transfer efficiency for solar‐light‐driven hydrogen generation.Cu‐doped zeolitic imidazolate framework‐8(ZIF‐8)rhombic dodecahedrons are transformed to hollow Cu‐ZIF‐8 nanoframes converted to Cu‐ZnS nanoframes with three‐dimensional photocatalytic active surfaces via anisotropic chemical etching,which is further converted to Cu‐ZnS nanoframes.By combining the merits of optimal heteroatom doping and frame‐like open architecture,the obtained 1%Cu‐doped ZnS nanoframe exhibits high photocatalytic activity under solar light irradiation with improved hydrogen production rate up to 8.30 mmol h^(–1) g^(–1) and excellent stability in the absence of cocatalysts,which is significantly improved in comparison with those of the bare ZnS and Cu‐ZnS with different morphologies.This work inspired by merging the merits of metal doping and anisotropic chemical etching may shed light on the rational design and fabrication of advanced photocatalysts.
文摘The development of hydrogen redox electric power generators for infinite cruising range electric vehicles represents a true technological breakthrough. Such systems consist of a polymer electrolyte membrane hydrogen electrolytic cell equipped with an electrostatic-induction potential-superposed water electrolytic cell that provides a stoichiometric H2-O2 fuel mixture during operation of the vehicle. This generator functions with zero power input, zero matter input and zero emission due to the so-called "zero power input" electrostatic-to-chemical energy conversion occurring in the electrolytic cell. Here, theoretical simulations were performed to verify the target performance of such generators, assuming a pair of FC (fuel cell) and electrolytic cell stacks, both of which are commercially available.
文摘Transparent oxyfluoride silicate precursor glasses and glass ceramics with the novel composition (1) SiO2-PbO-PbFE-Er2O3, (2) SiO2-GeOE-PbO-PbFE-Er2O3 (3) SiO2-Al2O3-Y2O3-Na2O-NaF-LiF-Er2O3-YbF3 doped with Er^3+ and co-doped with Er^3+/Yb^3+ ions were synthesized. X-ray diffraction analysis (XRD) and Er3+ absorption spectra revealed precipitation of PbF2 nanocrystals dispersed in the glassy matrix. Under 980 nm laser excitation, intense green, red and near IR bands of upconversion luminescence (UCL) were recorded both before and after heat treatment. In the glass ceramics the upconversion intensity increased significantly. To our knowledge, for the first time the composition of the glass ceramics characterized by the small-angle neutron scattering (SANS) showed the cluster organization of PbF2 nanocrystals.
文摘A novel level-shift LDMOS (lateral double-diffused metal oxide semiconductor) structure with the HV (high voltage) -interconnection for a 600 V-HVIC (high voltage integrated circuit) on thick SOI (silicon on insulator) is proposed. There are two original points in the proposed structure. One is the formation of the double floating p-layers under the HV-interconnection to prevent potential distribution in the drift from disturbing due to the HV-interconnection, and the other is a good combination between the LDMOS structure and multiple trench isolation to obtain the isolation performance over 600 V. From the proposed structure, the high blocking capability of the LDMOS, including both off- and on-breakdown voltages over 600 V and high hot carrier instability, and the isolation performance over 1,200 V can be obtained successfully. This paper will show numerical and experimental results in detail.
文摘The use of CO2-free energy sources for running SOEC (solid-oxide electrolysis cell) technologies has a great potential to reduce the carbon dioxide emissions compared to fossil fuel based technologies for hydrogen production. The operation of the electrolysis cell at higher temperature offers the benefit of increasing the efficiency of the process. The range of the operating temperature of the SOEC is typically between 800 ~C and 1,000 ~C. Main sources of degradation that affect the SOEC stack lifetime is related to the high operating temperature. To increase the electrolyser durability, one possible solution is to decrease the operating temperature down to 650 ~C, which represents the typical operating range of the ITSE (intermediate temperature steam electrolysis). This paper is related to the work of the JU-FCH project ADEL, which investigates different carbon-free energy sources with respect to potential coupling schemes to ITSE. A predominant focus of the analysis is put on solar concentrating energy systems (solar tower) and nuclear energy as energy sources to provide the required electricity and heat for the ITSE. This study will present an overview of the main considerations, the boundary conditions and the results concerning the development of coupling schemes of the energy conversion technologies to the electrolyser.
文摘Efficiency and power loss in the microelectronic devices is a major issue in power electronics applications. The engineers are challenged every year to increase power density and at the same time reduce the amount of power dissipated in the applications to keep the maximum temperatures under specifications. This situation drives a constant demand for better efficiencies in smaller packages. Traditional approaches to improve efficiency in DC/DC synchronous buck converters include reducing conduction losses in the MOSFETs (metal oxide semiconductor field effect transistors) through lower RDS (ON) (resistance drain to source in the ON state) devices and lowering switching losses through low-frequency operation. However, the incremental improvements in RDS (ON) are at a point of diminishing returns and low RDS (ON) devices have large parasitic capacitances that do not facilitate the high-frequency operation required to improve power density. The drive for higher efficiency and increased power in smaller packages is being addressed by advancements in both silicon and packaging technologies. The NexFET power block combines these two technologies to achieve higher levels of performance, and in half the space versus discrete MOSFETs. This article explains these new technologies and highlights their performance advantage.
基金supported by the National Natural Science Foundation of China (20772031 & 61006048)National Basic Research Program of China (973 Program) (2006CB806200)+1 种基金the Fundamental Research Funds for the Central Universities (WJ0913001)Scientific Committee of Shanghai (10520709700)
文摘The effects of chenodeoxycholic acid (CDCA) in a dye solution as a co-adsorbent on the photovoltaic performance of dye-sensitized solar cells (DSSCs) based on two organic dyes containing phenothiazine and triarylamine segments (P1 and P2) were investigated.It was found that the coadsorption of CDCA can hinder the formation of dye aggregates and improve electron injection yield and thus Jsc.This has also led to a rise in photovoltage,which is attributed to the decrease of charge recombination.The DSSC based on dye P2 showed better photovoltaic performance than P1:a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 89.5%,a short-circuit photocurrent density (Jsc) of 9.57 mA/cm2,an open-circuit photovoltage (Voc) of 697 mV,and a fill factor (FF) of 0.66,corresponding to an overall conversion efficiency of 4.42% under the standard global AM 1.5 solar light condition.The overall conversion efficiency was further improved to 5.31% (Jsc=10.36 mA/cm2,Voc=0.730 V,FF=0.70) upon addition of 10 mM CDCA to the dye solution for TiO2 sensitization.Electrochemical impedance data indicate that the electron lifetime was improved by coadsorption of CDCA,accounting for the significant improvement of Voc.These results suggest that interfacial engineering of the organic dye-sensitized TiO2 electrodes is important for highly efficient photovoltaic performance of the solar cell.
基金the National Natural Science Foundation of China(21875221,21890753,22162026,22225204,and U1967215)the National Key Research and Development Program of China(2016YFB0101202)+2 种基金the Youth Talent Support Program of High-Level Talents Special Support Plan in Henan Province(ZYQR201810148)Qiushi Scientific Research Initiation Plan of Zhengzhou University(32213243)the Distinguished Young Scholars Innovation Team of Zhengzhou University(32320275).
文摘The catalytic effect of electrode materials is one of the most crucial factors for achieving efficient electrochemical energy conversion and storage.Carbon-based metal composites were widely synthesized and employed as electrode materials because of their inherited outstanding properties.Usually,electrode materials can provide a higher capacity than the anticipated values,even beyond the theoretical limit.The origin of the extra capacity has not yet been explained accurately,and its formation mechanism is still ambiguous.Herein,we first summarized the current research progress and drawbacks in energy storage devices(ESDs),and elaborated the role of catalytic effect in enhancing the performance of ESDs as follows:promoting the evolution of the solid electrolyte interphase(SEI),accelerating the reversible conversion of discharge/charge products,and improving the conversion speed of the intermediate and the utilization rate of the active materials,thereby avoiding the shuttling effect.Additionally,a particular focus was placed on the interaction between the catalytic effect and energy storage performance in order to highlight the efficacy and role of the catalytic effect.We hope that this review could provide innovative ideas for designing the electrode materials with an efficient catalytic effect for ESDs to promote the development of this research field.
文摘Realizing personalized medicine requires integrating diverse data types with bioinformatics.The most vital data are genomic information for individuals that are from advanced next-generation sequencing(NGS) technologies at present.The technologies continue to advance in terms of both decreasing cost and sequencing speed with concomitant increase in the amount and complexity of the data.The prodigious data together with the requisite computational pipelines for data analysis and interpretation are stressors to IT infrastructure and the scientists conducting the work alike.Bioinformatics is increasingly becoming the rate-limiting step with numerous challenges to be overcome for translating NGS data for personalized medicine.We review some key bioinformatics tasks,issues,and challenges in contexts of IT requirements,data quality,analysis tools and pipelines,and validation of biomarkers.
基金Supported by the Soil Testing Laboratory at Federal University of Rio Grande do Sul (LAS-UFRGS), Brazil
文摘Simultaneous multi-element extraction has been increasing worldwide to improve soil laboratory testing quality and efficiency. This study sought to investigate the applicability of the Mehlich-1, Mehlich-3, and resin methods for simultaneous extraction of soil available P, K, Ca, and Mg as well as the effect of using conversion equations on nutrient recommendations for crops. Topsoil (0-20 cm) samples were taken from the most representative soil types used for crop production in southern Brazil with a wide range of chemical, physical, and mineralogical properties. Soil P, K, Ca, and Mg were simultaneously extracted using 1.0 mol L-1 KCl, Mehlich-1 and Mehlich-3 solutions, and membrane resin. The amounts of P extracted with the Mehlich-1 method were, on average, 50% lower than those extracted with the resin and Mehlich-3 methods. However, the resin method extracted the lowest amounts of K, Ca, and Mg. The use of conversion equations was suitable and it did not affect negatively the K recommendations for crops grown on soils of southern Brazil.
文摘The COVID-19 pandemic encouraged the use of plastic-based personal protective equipment (PPE), which aidedgreatly in its management. However, the increased production and usage of these PPEs put a strain on the environment,especially in developing and underdeveloped countries. This has led various researchers to study low-costand effective technologies for the recycling of these materials. One such material is disposable facemasks. However,previous studies have only been able to engage electrically powered reactors for their thermochemical conversion,which is a challenge as these reactors cannot be used in regions with an insufficient supply of electricity. In thisstudy, the authors utilized a biomass-powered reactor for the conversion of waste disposable facemasks and almondleaves into hybrid biochar. The reactor, which is relatively cheap, simple to use, environmentally friendly, and modifiedfor biochar production, is biomass-powered. The co-carbonization process, which lasted 100 min, produced a 46%biochar yield, which is higher than previously obtained biochar yields by other researchers. The biochar thus obtainedwas characterized to determine its properties. FTIR analysis showed that the biochar contained functional groupssuch as alkenes, alkynes, hydroxyls, amines, and carbonyls. The EDX analysis revealed that the biochar was primarilymade of carbon, tellurium, oxygen, and calcium in the ratios of 57%, 19%, 9%, and 7%, respectively. The inclusion ofthe facemask decreased the surface area and porosity of the biochar material, as evidenced by its surface area andpore characteristics.
文摘Plastic thermo-electrochemical ceils (thermocells) involving aqueous potassium ferricyanide/ferrocyanide electrolyte have been investigated as an alternative to conventional thermoelectrics for thermal energy harvesting. Plastic thermocells that consist of all pliable materials such as polyethylene terephthalate (PET), fabrics, and wires are flexible enough to be wearable on the human body and to be wrapped around cylindrical shapes. The performance of the thermocells is enhanced by incorporating carbon nanotubes into activated carbon textiles, due to improved charge transfer at the interface. In cold weather conditions (a surrounding temperature of 5 ℃), the thermocell generates a short-circuit current density of 0.39 A/m2 and maximum power density of 0.46 mW/m2 from body heat (temperature of 36℃). For practical use, we have shown that the thermocell charges up a capacitor when worn on a T-shirt by a person. We also have demonstrated that the electrical energy generated from waste pipe heat using a serial array of the thermocells and voltage converters can power a typical commercial light emitting diode (LED).
基金supported by the Natural Science Foundation of Guangdong Province of China (No.06025173)
文摘Small molecule organic solar cells (OSCs) with the structure of indium tin oxide (1TO)/molybdenum trioxide (MOO3) (5 nm)/rubrene (x nm)/fullerene (C70) (y nm)/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP) (6 nm)/aluminum (A1) (150 nm) are fabricated. The thickness of active layer for the devices is investigated in details. The results show that the optimum thicknesses of rubrene layer and C70 layer are 30 nm and 25 nm, respectively. The degradation of the device is also investigated. The result indicates that the open-circuit voltage (Voo) does not change, while the short-circuit current density (Jsc), fill factor (FF) and power conversion efficiency (PCE) decrease continuously with time. The degradation can be attributed to the oxygen in ambient diffusing and infiltrating into the active materials and reacting with C70 in cells, which can result in the increase of interfacial series resistance.
基金supported by the National High Technology Research and Development Program(Grant No.2011AA050511)Jiangsu"333"Project,the Priority Academic Program Development of Jiangsu Higher Education Institutions and Research and Innovation Project for College Graduates of Jiangsu Province(Grant No.CXLX13_722)
文摘To study the ferroelectric photovoltaic effect based on polycrystalline films, preparation of high-quality polycrystalline films with low leakage and high remnant polarization is essential. Polycrystalline BiFeO3 (BFO) thin films with extremely large remnant polarization (2Pr = 180 ~aC/cm2) were successfully deposited on glass substrates coated with indium tin oxide using a modified radio frequency magnetron sputtering method. Symmetric and asymmetric cells were constructed to investigate the ferroelectric photovoltaic effect in order to understand the relationship between polarization and photovoltaic response. All examined cells showed polarization-induced photovoltaic effect. Our findings also showed that the ferroelectric photovoltaic effect is highly dependent on the material used for the top electrode and the thickness of the polycrystalline film.
基金supported by the National Key Research and Development Program of China (2018YFB1500104)the National Natural Science Foundation of China (11574199 and 11911530142)+1 种基金Shanghai Pilot Program for Basic Research-Shanghai Jiao Tong Universitythe Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning
文摘Nonradiative recombination losses at defects in metal halide perovskite films are responsible for hindering the improvement of the photovoltaic performance and stability of perovskite solar cells(PSCs).Here,we report a feasible multifunctional additive strategy that uses cesium stearate to passivate defects in perovskite films and simultaneously enhances the tolerance to light and moisture stress.Nonradiative recombination losses are effectively suppressed in target films that exhibit improved crystallinity,low trap-state density,and enhanced carrier separation and transportation.The present strategy hence boosts the power conversion efficiency of the pi-n structured PSC to 23.41%.Our device also shows good stability in ambient air without encapsulation,maintaining 91.6%of the initial efficiency after 720 h.