Tree-ring width(RW),density,elemental com-position,and stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)are widely used as proxies to assess climate change,ecology,and environmental pollution;however,a specific pret...Tree-ring width(RW),density,elemental com-position,and stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)are widely used as proxies to assess climate change,ecology,and environmental pollution;however,a specific pretreat-ment has been needed for each proxy.Here,we developed a method by which each proxy can be measured in the same sample.First,the sample is polished for ring width meas-urement.After obtaining the ring width data,the sample is cut to form a 1-mm-thick wood plate.The sample is then mounted in a vertical sample holder,and gradually scanned by an X-ray beam.Simultaneously,the count rates of the fluorescent photons of elements(for chemical characteriza-tion)and a radiographic grayscale image(for wood density)are obtained,i.e.the density and the element content are obtained.Then,cellulose is isolated from the 1-mm wood plate by removal of lignin,and hemicellulose.After producing this cellulose plate,cellulose subsamples are separated by knife under the microscope for inter-annual and intra-annual stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)analysis.Based on this method,RW,density,elemental composition,δ^(13)C,and δ^(18)O can be measured from the same sample,which reduces sample amount and treatment time,and is helpful for multi-proxy comparison and combination research.展开更多
In this paper, a combined viscoelasticity-viscoplasticity model, coupled with anisotropic damage and moisture effects, is developed for short fiber reinforced polymers (SFRPs) with different fiber contents and subject...In this paper, a combined viscoelasticity-viscoplasticity model, coupled with anisotropic damage and moisture effects, is developed for short fiber reinforced polymers (SFRPs) with different fiber contents and subjected to a variety of strain rates. In our model, a rate-dependent yield surface for the matrix phase is employed to identify initial yielding of the material. When an SFRP is loaded at small deformation before yielding, its viscoelastic behavior can be described using the generalized Maxwell model, while when plasticity occurs, a scalar internal state variable (ISV) is used to capture the hardening behavior caused by the polymeric constituent of the composite. The material degradation due to the moisture absorption of the composite is modeled by employing another type of ISV with different evolution equations. The complicated damage state of the SFRPs is captured by a second rank tensor, which is further decomposed to model the subscale damage mechanisms of micro-voids/cracks nucleation, growth and coalescence. It is concluded that the proposed constitutive model can be used to accurately describe complicated behaviors of SFRPs because the results predicted from the model are in good agreement with the experimental data.展开更多
Two dimensional halide perovskites are emerging as attractive electroluminescent materials for developing high-performance light-emitting devices owing to their unique structures and/or superior optoelectronic propert...Two dimensional halide perovskites are emerging as attractive electroluminescent materials for developing high-performance light-emitting devices owing to their unique structures and/or superior optoelectronic properties.This review begins with an introduction to the working principles of and the key figures for evaluating the performance of LEDs.Secondly,the structure and optoelectronic properties of two dimensional perovskites are summarized and discussed. Their advantages in LED application over their 3D counterparts are systematically analyzed.Following the theoretically discussion,the progresses on the preparation of two dimensional perovskite materials as well as their performances in LEDs have been summarized. At last,several challenges and prospects are presented for achieving high performance 2D perovskite-based LEDs.展开更多
Improving the quality of the perovskite active layer is crucial to obtaining high performance perovskite solar cells(PSCs). In this work, by introducing formic acid into the formamidinium lead iodide(FAPbI3)precursor ...Improving the quality of the perovskite active layer is crucial to obtaining high performance perovskite solar cells(PSCs). In this work, by introducing formic acid into the formamidinium lead iodide(FAPbI3)precursor solution, we managed to achieve reduced colloidal size in the solution, leading to more uniform deposition of FAPbI3 film with lower trap state density and higher carrier mobility. The solar cells based on the FAPbI3 absorber layer modified with formic acid show significantly better photovoltaic performance than that on the reference FAPbI3 film without formic acid. The device performance shows a close correlation with the colloidal size. Within the range studied from 6.7 to 1.0 nm, the smaller the colloidal size is, the higher the solar cell efficiency. More specifically, the cell efficiency is improved from17.82% for the control cell without formic acid to 19.81% when 0.764 M formic acid was used. Formic acid has also been added into a CH3NH3PbI3(MAPbI3) precursor solution, which exhibits a similar effect on the resulting MAPb I3 films and solar cells, with efficiency improved from 16.07% to 17.00%.展开更多
Interface engineering is an effective way to improve efficiency and long-term stability of perovskite solar cells(PSCs).Herein,an ionic compound tetrabutylammonium hexafluorophosphate(TP6)is adopted to passivate surfa...Interface engineering is an effective way to improve efficiency and long-term stability of perovskite solar cells(PSCs).Herein,an ionic compound tetrabutylammonium hexafluorophosphate(TP6)is adopted to passivate surface defects of the perovskite film.It is found that TP6 effectively reduced the surface defects,especially at the grain boundaries where the defects are abundant.Meanwhile,the exposed long alkyl chains and fluorine atoms in the TP6 enhanced the moisture stability of the perovskite film due to its strong hydrophobicity.In addition,the driving force of charge carrier separation and transport is increased by enlarged built-in potential.Consequently,the power conversion efficiency(PCE)of PSCs is significantly improved from 20.59% to 22.41%by increased open-circuit voltage(V_(oc))and fill factor(FF).The unencapsulated device with TP6 treatment exhibits better stability than the control device,and the PCE retains-80%of its initial PCE after 30 days under 15%-25%relative humidity in storage,while the PCE of the control device declines by more than 50%.展开更多
Organic–inorganic single-crystalline perovskites have attracted significant attentions due to their exceptional progress in intrinsic properties' investigation and applications in photovoltaics and optoelectronics. ...Organic–inorganic single-crystalline perovskites have attracted significant attentions due to their exceptional progress in intrinsic properties' investigation and applications in photovoltaics and optoelectronics. In this study, the large perovskite CH3NH3PbI3 single crystal with the largest length of 80 mm was prepared through the method of inverse-temperature crystallization. Meanwhile, the mass production of integrate photodetectors have been fabricated on the single-crystalline wafer and the photoresponse performances were investigated. The results show that the single-crystalline photodetectors have broad spectrum response to 900 nm, rapid response speed(〈40 μs) and excellent stability. These findings are of great importance for future promising perovskite single crystalline for integrated photoelectronic application.展开更多
This paper presents a similitude and computational analysis of the performance of a scaled-down model of a paddle wheel style hydrokinetic generator device used for generating power from the flow of a river. The paddl...This paper presents a similitude and computational analysis of the performance of a scaled-down model of a paddle wheel style hydrokinetic generator device used for generating power from the flow of a river. The paddle wheel dimensions used in this work are one-thirtieth scale of the full-size paddle wheel. The reason for simulating the scaled-down model was to prepare for the testing of a scaled-down physical prototype. Computational Fluid Dynamics using ANSYS Fluent 14.0 software was used for the computational analysis. The scaled-down dimensions were used in the simulations to predict the power that can be generated from the scaled size model of the paddle wheel, having carried out similitude analysis between the scaled down size and its full-size. The dimensionless parameters employed in achieving similitude are the Strouhal number, power coefficient, and pressure coefficient. The power estimation of the full-size was predicted from the scaled size of the paddle wheel based on the similitude analysis.展开更多
In this paper,CaO/bio-char was synthesized by directly co-pyrolysis of Ca(OH)_(2) and rice straw,and used as catalyst to catalytic pyrolysis of soybean oil to produce high quality biofuel.In this co-pyrolysis process,...In this paper,CaO/bio-char was synthesized by directly co-pyrolysis of Ca(OH)_(2) and rice straw,and used as catalyst to catalytic pyrolysis of soybean oil to produce high quality biofuel.In this co-pyrolysis process,CaO particles has been successfully embedded on the bio-char surface.During the catalytic pyrolysis process,CaO/biochar showed a good catalytic performance on the deoxygenation of soybean oil.Pyrolysis temperature affected the pyrolysis reactions and pyrolytic products distributions dramatically,higher pyrolysis temperature lead to seriously cracking reactions,lower bio-oil yield and higher gases yield,and lower pyrolysis temperature lead to higher bio-oil yield with higher oxygenated compounds content and lower hydrocarbons contents,the suitable pyrolysis temperature was around 650℃.Under the optimal conditions(650℃ with WHSV at 6.4 h^(−1) and carrier gas flow rate at 100 ml/min),the selectivity(%)of hydrocarbons in the bio-oil was more than 90%.CaO/bio-char catalyst still shows good catalytic deoxygenation activity after 4 cycles.1 g of CaO/bio-char catalyst can catalyze pyrolysis of 32 g of soybean oil to produce high-quality liquid fuel.Bio-char based catalyst has been proved to be a promising catalyst for catalytic conversion of triglyceride-based lipids into high quality liquid biofuel.展开更多
This paper proposes the continuous-time singular value decomposition (SVD) for the impulse response function, a special kind of Green’s functions, in order to find a set of singular functions and singular values so t...This paper proposes the continuous-time singular value decomposition (SVD) for the impulse response function, a special kind of Green’s functions, in order to find a set of singular functions and singular values so that the convolutions of such function with the set of singular functions on a specified domain are the solutions to the inhomogeneous differential equations for those singular functions. A numerical example was illustrated to verify the proposed method. Besides the continuous-time SVD, a discrete-time SVD is also presented for the impulse response function, which is modeled using a Toeplitz matrix in the discrete system. The proposed method has broad applications in signal processing, dynamic system analysis, acoustic analysis, thermal analysis, as well as macroeconomic modeling.展开更多
Taking Meipi Village and Zhuqiao Village as the research objects,the external space,internal space and architecture form of the ancient villages were compared,and the law and essence of village pattern under different...Taking Meipi Village and Zhuqiao Village as the research objects,the external space,internal space and architecture form of the ancient villages were compared,and the law and essence of village pattern under different cultures were summarized in this article,so as to provide ideas for the preservation and continuation of Jiangxi's history and culture and innovative rural development.展开更多
Perovskite solar cells have aroused a worldwide research upsurge in recent years due to their soaring photovoltaic performance,ease of solution processing,and low cost.The power conversion efficiency record is constan...Perovskite solar cells have aroused a worldwide research upsurge in recent years due to their soaring photovoltaic performance,ease of solution processing,and low cost.The power conversion efficiency record is constantly being broken and has recently reached 26.1%in the lab,which is comparable to the established photovoltaic technologies such as crystalline silicon,copper indium gallium selenide and cadmium telluride(CdTe)solar cells.Currently,perovskite solar cells are standing at the entrance of industrialization,where huge opportunities and risks coexist.However,towards commercialization,challenges of up-scaling,stability and lead toxicity still remain,the proper handling of which could potentially lead to the widespread adoption of perovskite solar cells as a low-cost and efficient source of renewable energy.This review gives a holistic analysis of the path towards commercialization for perovskite solar cells.A comprehensive overview of the current state-of-the-art level for perovskite solar cells and modules will be introduced first,with respect to the module efficiency,stability and current status of industrialization.We will then discuss the challenges that get in the way of commercialization and the corresponding strategies to address them,involving the upscaling,the stability and the lead toxicity issue.Insights into the future direction of commercialization of perovskite photovoltaics was also provided,including the flexible perovskite cells and modules and perovskite indoor photovoltaics.Finally,the future perspectives towards commercialization are put forward.展开更多
Graphene oxide(GO)with one-atom-thick exhibit remarkable molecule sieving properties,but its low permeance flux renders it difficult to be applied in practice as a high-permeance separation membrane.In this study,we d...Graphene oxide(GO)with one-atom-thick exhibit remarkable molecule sieving properties,but its low permeance flux renders it difficult to be applied in practice as a high-permeance separation membrane.In this study,we design complex membrane from covalently crosslinked GO,polydopamine(PDA),and 3-aminopropytriethoxysilane(APTES)as building blocks to fabricate the high-permeance GO-based membrane via the vacuum filtration method.A branched crosslinking product(PDA/APTES)working as a clamp grasped the hydrophilic functional groups(hydroxyl,epoxy,carboxyl)on GO for improving the GO membrane flux.The interlayer structure of the GO membrane was optimized according to the crosslinker concentration,reaction time,initial p H,and temperature for RGO/PDA/APTES(RGPA)in this study.At the optimized reaction conditions including the crosslinker concentration of 1.4 m L/L,the temperature of 80°C,the time of 16 h,and the initial p H of 8.5 for RGPA mixture,the interlayer gallery of RGPA membrane was effectively tunes,endowing high flux ranging from 11.98 L m^(-2)h^(-1)to 1823.97 L m^(-2)h^(-1).Besides,the RGPA membrane ensured the high rejections to dye solutions such as methylene blue(MB)(>99%)and congo red(CR)(>90%).Meanwhile,the superior reusable performance of the RGPA membrane was achieved,together with the rejections for MB and CR to 96.32%and 93.1%after 4 cycles,respectively.Also,the RGPA membrane possessed superior anti-fouling performances for bovine serum albumin(BSA)aqueous solution and excellent stabilities in harsh conditions(p H 3,7 and 11).Grafting the crosslinker onto GO nanosheets exhibits the distinct advantages of achieving the high flux,high rejections to dyes,and superior reusable performance of membranes,posing a great application potential for membrane separation technology in wastewater treatment.展开更多
Dear Editor,As one of the most important crops to supply the majority of plant oil and protein for the whole world,soybean is facing an increasing global demand.The reference genome of accession"Williams82"o...Dear Editor,As one of the most important crops to supply the majority of plant oil and protein for the whole world,soybean is facing an increasing global demand.The reference genome of accession"Williams82"opened the gate of genomics research in soybean(Schmutz et al.,2010).After that,vast multi-omics data were generated,thereby providing valuable resources for functional study and molecular breeding.Parts of these data have been collected in different soybean databases(see details in Supplemental Table 1),such as Soybase(Grant et al.,2010)and SoyKB(Joshi et al.,2012),which made valuable efforts to facilitate the wide utility of these data.Nevertheless,these existing databases poorly tackled multi-omics data integration and interactivity for soybean,provoking tremendous challenges for researchers to deal with these big omics data,particularly considering the unprecedented rate of data growth(Yang et al.,2021).Thus,constructing an integrated multi-omics database for soybean that provides a one-stop solution for big data mining with friendly interactivity is highly desired.展开更多
Defect passivation is one of the important strategies to improve the efficiency and stability of perovskite solar cells.In this work,2,6-di-tert-butyl-4-methylphenol(BHT)as antioxidant was introduced into the perovski...Defect passivation is one of the important strategies to improve the efficiency and stability of perovskite solar cells.In this work,2,6-di-tert-butyl-4-methylphenol(BHT)as antioxidant was introduced into the perovskite precursor solution to improve the quality of the prepared perovskite films,so that these films performed a larger and uniform grain size.Moreover,the-OH functional group in BHT interacts with I-,thus reducing the density of defect states and inhibiting the non-radiative recombination.The presence of hydrophobic groups in BHT protects the film from moisture erosion and improves the long-term stability of PSCs devices.The maximum photoelectric conversion efficiency of the constructed ITO/SnO_(2)/BHTMAPbI_(3)/Carbon device is 16.88%,and the unpackaged cell maintains the initial efficiency of 99.3%after698 h of storage under the environmental condition of 30%humidity.This work provides an efficient approach to improve the performance of printable hole transport layer-free carbon electrode perovskite solar cells.展开更多
Defect-rich,highly porous two-dimensional carbon nanosheets(CNS) have attracted tremendous research interests in catalysis and environmental purification and other fields,because of their unique micromorphology,chemic...Defect-rich,highly porous two-dimensional carbon nanosheets(CNS) have attracted tremendous research interests in catalysis and environmental purification and other fields,because of their unique micromorphology,chemical stability and high specific surface area.Herein,in this work,we report a new solution to synthesize an ultrathin two-dimensional CNS with rich defects and abundant pores via two-step etching the Ti_(3)AlC_(2)with the help of I2and NaOH.The CNS thickness,specific surface area and pore volume could be all tunable by adding the amount of I2.And the highest specific surface area and pore volume of the synthesized 2D CNS can be achieved 1134.4 m^(2)/g and 0.80 cm^(3)/g,with a thickness of only 0.64 nm and a yield of 35.9%.When employed as the anodes for lithium-ion batteries,the synthesized CNS anodes exhibit good cycling and rate capabilities.This work provides a novel and facile strategy for synthesizing highly porous and defective 2D carbon materials with good lithium storage properties.展开更多
The defects within perovskite films are the fatal roadblock limiting the performance of perovskite solar cells(PSCs).Herein,we develop a patching strategy to obtain high quality perovskite film using bifunctional trif...The defects within perovskite films are the fatal roadblock limiting the performance of perovskite solar cells(PSCs).Herein,we develop a patching strategy to obtain high quality perovskite film using bifunctional trifuorophenylacetic acid(TFPA).Theoretical calculation and experiments reveal that the-COOH groups in TFPA effectively passivate the deep-energy-level defects of perovskite by combining with Pb clusters on the perovskite grain surfaces to enhance the efficiency of PSCs,and hydrophobic benzene groups containing fluorine in TFPA are exposed to improve the stability of PSCs.The power conversion effi-ciency(PCE)of PSCs with TFPA is enhanced from 22.95%to 24.56%.Most importantly,we successfully fabricated flexible PSCs using TFPA with the high PCE of 22.65%.The devices with TFPA maintain 93.22%of the initial efficiency MPP under continuous irradiation for 10.5 h,while the devices without TFPA only retain 82.22%of the initial efficiency under the same conditions for just 5 h.Meanwhile,the unsealed devices with TFPA hold 93.59%of the initial efficiency when stored in air for 3912 h.展开更多
Dormancy or germination is an essential question that seed plants have to face.Under natural circumstances,seeds of plants usually maintain the status of dormancy until they meet the optimal condition to trigger the g...Dormancy or germination is an essential question that seed plants have to face.Under natural circumstances,seeds of plants usually maintain the status of dormancy until they meet the optimal condition to trigger the germination process(Finkelstein et al.,2008;Shu et al.,2015).However,things are different in agriculture,i.e.展开更多
基金supported the National Natural Science Foundation of China (42022059,41888101)the Strategic Priority Research Program of the Chinese Academy of Sciences,China (Grant No.XDB26020000)+1 种基金the Key Research Program of the Institute of Geology and Geophysics (CAS Grant IGGCAS-201905)the CAS Youth Interdisciplinary Team (JCTD-2021-05).
文摘Tree-ring width(RW),density,elemental com-position,and stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)are widely used as proxies to assess climate change,ecology,and environmental pollution;however,a specific pretreat-ment has been needed for each proxy.Here,we developed a method by which each proxy can be measured in the same sample.First,the sample is polished for ring width meas-urement.After obtaining the ring width data,the sample is cut to form a 1-mm-thick wood plate.The sample is then mounted in a vertical sample holder,and gradually scanned by an X-ray beam.Simultaneously,the count rates of the fluorescent photons of elements(for chemical characteriza-tion)and a radiographic grayscale image(for wood density)are obtained,i.e.the density and the element content are obtained.Then,cellulose is isolated from the 1-mm wood plate by removal of lignin,and hemicellulose.After producing this cellulose plate,cellulose subsamples are separated by knife under the microscope for inter-annual and intra-annual stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)analysis.Based on this method,RW,density,elemental composition,δ^(13)C,and δ^(18)O can be measured from the same sample,which reduces sample amount and treatment time,and is helpful for multi-proxy comparison and combination research.
文摘In this paper, a combined viscoelasticity-viscoplasticity model, coupled with anisotropic damage and moisture effects, is developed for short fiber reinforced polymers (SFRPs) with different fiber contents and subjected to a variety of strain rates. In our model, a rate-dependent yield surface for the matrix phase is employed to identify initial yielding of the material. When an SFRP is loaded at small deformation before yielding, its viscoelastic behavior can be described using the generalized Maxwell model, while when plasticity occurs, a scalar internal state variable (ISV) is used to capture the hardening behavior caused by the polymeric constituent of the composite. The material degradation due to the moisture absorption of the composite is modeled by employing another type of ISV with different evolution equations. The complicated damage state of the SFRPs is captured by a second rank tensor, which is further decomposed to model the subscale damage mechanisms of micro-voids/cracks nucleation, growth and coalescence. It is concluded that the proposed constitutive model can be used to accurately describe complicated behaviors of SFRPs because the results predicted from the model are in good agreement with the experimental data.
基金funded by the National Key Research and Development Program of China (2017YFA0204800/2016YFA0202403)the Fundamental Research Funds for the Central Universities (2018CBLZ006)+3 种基金National Natural Science Foundation of China (61604091 and 61674098)the 111 Project (B14041)the Changjiang Scholar and Innovative Research Team (IRT_14R33)the Chinese National 1000-talent-plan program (1110010341)
文摘Two dimensional halide perovskites are emerging as attractive electroluminescent materials for developing high-performance light-emitting devices owing to their unique structures and/or superior optoelectronic properties.This review begins with an introduction to the working principles of and the key figures for evaluating the performance of LEDs.Secondly,the structure and optoelectronic properties of two dimensional perovskites are summarized and discussed. Their advantages in LED application over their 3D counterparts are systematically analyzed.Following the theoretically discussion,the progresses on the preparation of two dimensional perovskite materials as well as their performances in LEDs have been summarized. At last,several challenges and prospects are presented for achieving high performance 2D perovskite-based LEDs.
基金supported by the National Key Research and Development Program of China(NO.2016YFA0202403/2017YFA0204800)the National Natural Science Foundation of China(61604091 and 61674098)+3 种基金the 111 Project(B14041)the National University Research Fund(Grant Nos.GK261001009,GK201603107)the Changjiang Scholar and Innovative Research Team(IRT_14R33)the Chinese National 1000-talent-plan program(1110010341)。
文摘Improving the quality of the perovskite active layer is crucial to obtaining high performance perovskite solar cells(PSCs). In this work, by introducing formic acid into the formamidinium lead iodide(FAPbI3)precursor solution, we managed to achieve reduced colloidal size in the solution, leading to more uniform deposition of FAPbI3 film with lower trap state density and higher carrier mobility. The solar cells based on the FAPbI3 absorber layer modified with formic acid show significantly better photovoltaic performance than that on the reference FAPbI3 film without formic acid. The device performance shows a close correlation with the colloidal size. Within the range studied from 6.7 to 1.0 nm, the smaller the colloidal size is, the higher the solar cell efficiency. More specifically, the cell efficiency is improved from17.82% for the control cell without formic acid to 19.81% when 0.764 M formic acid was used. Formic acid has also been added into a CH3NH3PbI3(MAPbI3) precursor solution, which exhibits a similar effect on the resulting MAPb I3 films and solar cells, with efficiency improved from 16.07% to 17.00%.
基金funded by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA17040506)the National Key Research and Development Program of China (2017YFA0204800/2016YFA0202403)+6 种基金the Key Program project of the National Natural Science Foundation of China (51933010)the National Natural Science Foundation of China (61974085)the 111 Project (B21005)the Changjiang Scholars and Innovative Research Team (IRT_14R33)the National University Research Fund (GK201903051)the Research Start-up Fund from Shaanxi Normal University (1110020142)the Shanxi Science and Technology Department (20201101012).
文摘Interface engineering is an effective way to improve efficiency and long-term stability of perovskite solar cells(PSCs).Herein,an ionic compound tetrabutylammonium hexafluorophosphate(TP6)is adopted to passivate surface defects of the perovskite film.It is found that TP6 effectively reduced the surface defects,especially at the grain boundaries where the defects are abundant.Meanwhile,the exposed long alkyl chains and fluorine atoms in the TP6 enhanced the moisture stability of the perovskite film due to its strong hydrophobicity.In addition,the driving force of charge carrier separation and transport is increased by enlarged built-in potential.Consequently,the power conversion efficiency(PCE)of PSCs is significantly improved from 20.59% to 22.41%by increased open-circuit voltage(V_(oc))and fill factor(FF).The unencapsulated device with TP6 treatment exhibits better stability than the control device,and the PCE retains-80%of its initial PCE after 30 days under 15%-25%relative humidity in storage,while the PCE of the control device declines by more than 50%.
基金support from the National Key Research and Development Program of China(no.2016YFA0202403)National Natural Science Foundation of China(nos.61604091/61674098)+3 种基金the 111 Project(B14041)the National University Research Fund(grant nos.GK261001009,GK201603107)Changjiang Scholar and Innovative Research Team(IRT_14R33)the Chinese National 1000-talent-plan program(1110010341)
文摘Organic–inorganic single-crystalline perovskites have attracted significant attentions due to their exceptional progress in intrinsic properties' investigation and applications in photovoltaics and optoelectronics. In this study, the large perovskite CH3NH3PbI3 single crystal with the largest length of 80 mm was prepared through the method of inverse-temperature crystallization. Meanwhile, the mass production of integrate photodetectors have been fabricated on the single-crystalline wafer and the photoresponse performances were investigated. The results show that the single-crystalline photodetectors have broad spectrum response to 900 nm, rapid response speed(〈40 μs) and excellent stability. These findings are of great importance for future promising perovskite single crystalline for integrated photoelectronic application.
文摘This paper presents a similitude and computational analysis of the performance of a scaled-down model of a paddle wheel style hydrokinetic generator device used for generating power from the flow of a river. The paddle wheel dimensions used in this work are one-thirtieth scale of the full-size paddle wheel. The reason for simulating the scaled-down model was to prepare for the testing of a scaled-down physical prototype. Computational Fluid Dynamics using ANSYS Fluent 14.0 software was used for the computational analysis. The scaled-down dimensions were used in the simulations to predict the power that can be generated from the scaled size model of the paddle wheel, having carried out similitude analysis between the scaled down size and its full-size. The dimensionless parameters employed in achieving similitude are the Strouhal number, power coefficient, and pressure coefficient. The power estimation of the full-size was predicted from the scaled size of the paddle wheel based on the similitude analysis.
基金The paper was supported by the Natural Science Foundation of China(No.51906112)Natural Science Foundation of Jiangsu Province(No.BK20180548)+1 种基金China Postdoctoral Science Foundation(2019M651852)“Innovation&Entrepreneurship Talents”Introduction Plan of Jiangsu Province.
文摘In this paper,CaO/bio-char was synthesized by directly co-pyrolysis of Ca(OH)_(2) and rice straw,and used as catalyst to catalytic pyrolysis of soybean oil to produce high quality biofuel.In this co-pyrolysis process,CaO particles has been successfully embedded on the bio-char surface.During the catalytic pyrolysis process,CaO/biochar showed a good catalytic performance on the deoxygenation of soybean oil.Pyrolysis temperature affected the pyrolysis reactions and pyrolytic products distributions dramatically,higher pyrolysis temperature lead to seriously cracking reactions,lower bio-oil yield and higher gases yield,and lower pyrolysis temperature lead to higher bio-oil yield with higher oxygenated compounds content and lower hydrocarbons contents,the suitable pyrolysis temperature was around 650℃.Under the optimal conditions(650℃ with WHSV at 6.4 h^(−1) and carrier gas flow rate at 100 ml/min),the selectivity(%)of hydrocarbons in the bio-oil was more than 90%.CaO/bio-char catalyst still shows good catalytic deoxygenation activity after 4 cycles.1 g of CaO/bio-char catalyst can catalyze pyrolysis of 32 g of soybean oil to produce high-quality liquid fuel.Bio-char based catalyst has been proved to be a promising catalyst for catalytic conversion of triglyceride-based lipids into high quality liquid biofuel.
文摘This paper proposes the continuous-time singular value decomposition (SVD) for the impulse response function, a special kind of Green’s functions, in order to find a set of singular functions and singular values so that the convolutions of such function with the set of singular functions on a specified domain are the solutions to the inhomogeneous differential equations for those singular functions. A numerical example was illustrated to verify the proposed method. Besides the continuous-time SVD, a discrete-time SVD is also presented for the impulse response function, which is modeled using a Toeplitz matrix in the discrete system. The proposed method has broad applications in signal processing, dynamic system analysis, acoustic analysis, thermal analysis, as well as macroeconomic modeling.
文摘Taking Meipi Village and Zhuqiao Village as the research objects,the external space,internal space and architecture form of the ancient villages were compared,and the law and essence of village pattern under different cultures were summarized in this article,so as to provide ideas for the preservation and continuation of Jiangxi's history and culture and innovative rural development.
基金the National Key Research and Development Program of China(2022YFB3803300 and 2023YFE0116800)Beijing Natural Science Foundation(IS23037).
文摘Perovskite solar cells have aroused a worldwide research upsurge in recent years due to their soaring photovoltaic performance,ease of solution processing,and low cost.The power conversion efficiency record is constantly being broken and has recently reached 26.1%in the lab,which is comparable to the established photovoltaic technologies such as crystalline silicon,copper indium gallium selenide and cadmium telluride(CdTe)solar cells.Currently,perovskite solar cells are standing at the entrance of industrialization,where huge opportunities and risks coexist.However,towards commercialization,challenges of up-scaling,stability and lead toxicity still remain,the proper handling of which could potentially lead to the widespread adoption of perovskite solar cells as a low-cost and efficient source of renewable energy.This review gives a holistic analysis of the path towards commercialization for perovskite solar cells.A comprehensive overview of the current state-of-the-art level for perovskite solar cells and modules will be introduced first,with respect to the module efficiency,stability and current status of industrialization.We will then discuss the challenges that get in the way of commercialization and the corresponding strategies to address them,involving the upscaling,the stability and the lead toxicity issue.Insights into the future direction of commercialization of perovskite photovoltaics was also provided,including the flexible perovskite cells and modules and perovskite indoor photovoltaics.Finally,the future perspectives towards commercialization are put forward.
基金financial support from the Sichuan Youth Science and Technology Innovation Research Team(No.2020JDTD0018)the Regional Innovation Cooperation project of Sichuan Province(No.2021YFQ0046)+2 种基金the Science and Technology Plan Project of Sichuan Province(No.2019YJ0302)the National Natural Science Foundation of China(No.21707111)The Opening Project of Oil&Gas Field Chemistry Key Laboratory of Sichuan Province(No.YQKF202106)。
文摘Graphene oxide(GO)with one-atom-thick exhibit remarkable molecule sieving properties,but its low permeance flux renders it difficult to be applied in practice as a high-permeance separation membrane.In this study,we design complex membrane from covalently crosslinked GO,polydopamine(PDA),and 3-aminopropytriethoxysilane(APTES)as building blocks to fabricate the high-permeance GO-based membrane via the vacuum filtration method.A branched crosslinking product(PDA/APTES)working as a clamp grasped the hydrophilic functional groups(hydroxyl,epoxy,carboxyl)on GO for improving the GO membrane flux.The interlayer structure of the GO membrane was optimized according to the crosslinker concentration,reaction time,initial p H,and temperature for RGO/PDA/APTES(RGPA)in this study.At the optimized reaction conditions including the crosslinker concentration of 1.4 m L/L,the temperature of 80°C,the time of 16 h,and the initial p H of 8.5 for RGPA mixture,the interlayer gallery of RGPA membrane was effectively tunes,endowing high flux ranging from 11.98 L m^(-2)h^(-1)to 1823.97 L m^(-2)h^(-1).Besides,the RGPA membrane ensured the high rejections to dye solutions such as methylene blue(MB)(>99%)and congo red(CR)(>90%).Meanwhile,the superior reusable performance of the RGPA membrane was achieved,together with the rejections for MB and CR to 96.32%and 93.1%after 4 cycles,respectively.Also,the RGPA membrane possessed superior anti-fouling performances for bovine serum albumin(BSA)aqueous solution and excellent stabilities in harsh conditions(p H 3,7 and 11).Grafting the crosslinker onto GO nanosheets exhibits the distinct advantages of achieving the high flux,high rejections to dyes,and superior reusable performance of membranes,posing a great application potential for membrane separation technology in wastewater treatment.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA24000000,XDA19050302,and XDA24040201)the Science and Technology Innovation 2030-Major Project(2022ZD04017)+5 种基金the National Natural Science Foundation of China(32030021,32000475,and 32201775)the National Key Research and Development Program of China(2021YFF1001201)the Taishan Scholars Programthe Xplorer Prize Awardthe Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y2021038)the China National Postdoctoral Program for innovative Talents(BX2021354).
文摘Dear Editor,As one of the most important crops to supply the majority of plant oil and protein for the whole world,soybean is facing an increasing global demand.The reference genome of accession"Williams82"opened the gate of genomics research in soybean(Schmutz et al.,2010).After that,vast multi-omics data were generated,thereby providing valuable resources for functional study and molecular breeding.Parts of these data have been collected in different soybean databases(see details in Supplemental Table 1),such as Soybase(Grant et al.,2010)and SoyKB(Joshi et al.,2012),which made valuable efforts to facilitate the wide utility of these data.Nevertheless,these existing databases poorly tackled multi-omics data integration and interactivity for soybean,provoking tremendous challenges for researchers to deal with these big omics data,particularly considering the unprecedented rate of data growth(Yang et al.,2021).Thus,constructing an integrated multi-omics database for soybean that provides a one-stop solution for big data mining with friendly interactivity is highly desired.
基金the financial support from the National Natural Science Foundation of China(Nos.22169022,22162026 and 62104137)the Shaanxi Technical Innovation Guidance Project of China(No.2018HJCG-17)+1 种基金the China National Postdoctoral Program for Innovative Talents(No.BX2021173)the China Postdoctoral Science Foundation(No.2021M702058)。
文摘Defect passivation is one of the important strategies to improve the efficiency and stability of perovskite solar cells.In this work,2,6-di-tert-butyl-4-methylphenol(BHT)as antioxidant was introduced into the perovskite precursor solution to improve the quality of the prepared perovskite films,so that these films performed a larger and uniform grain size.Moreover,the-OH functional group in BHT interacts with I-,thus reducing the density of defect states and inhibiting the non-radiative recombination.The presence of hydrophobic groups in BHT protects the film from moisture erosion and improves the long-term stability of PSCs devices.The maximum photoelectric conversion efficiency of the constructed ITO/SnO_(2)/BHTMAPbI_(3)/Carbon device is 16.88%,and the unpackaged cell maintains the initial efficiency of 99.3%after698 h of storage under the environmental condition of 30%humidity.This work provides an efficient approach to improve the performance of printable hole transport layer-free carbon electrode perovskite solar cells.
基金financially supported by the National Natural Science Foundation of China (No. 51902036)Natural Science Foundation of Chongqing Science & Technology Commission (No. cstc2019jcyj-msxm1407)+4 种基金Natural Science Foundation of Jiangsu Province (No. BK20200047)Natural Science Foundation of Chongqing Technology and Business University (No. 1952009)the Science and Technology Research Program of Chongqing Education Commission (Nos. KJQN201900826 and KJQN201800808)the Venture & Innovation Support Program for Chongqing Overseas Returnees (Nos. CX2021046 and CX2018129)the Innovation Group of New Technologies for Industrial Pollution Control of Chongqing Education Commission (No. CXQT19023)。
文摘Defect-rich,highly porous two-dimensional carbon nanosheets(CNS) have attracted tremendous research interests in catalysis and environmental purification and other fields,because of their unique micromorphology,chemical stability and high specific surface area.Herein,in this work,we report a new solution to synthesize an ultrathin two-dimensional CNS with rich defects and abundant pores via two-step etching the Ti_(3)AlC_(2)with the help of I2and NaOH.The CNS thickness,specific surface area and pore volume could be all tunable by adding the amount of I2.And the highest specific surface area and pore volume of the synthesized 2D CNS can be achieved 1134.4 m^(2)/g and 0.80 cm^(3)/g,with a thickness of only 0.64 nm and a yield of 35.9%.When employed as the anodes for lithium-ion batteries,the synthesized CNS anodes exhibit good cycling and rate capabilities.This work provides a novel and facile strategy for synthesizing highly porous and defective 2D carbon materials with good lithium storage properties.
基金111 Project,Grant/Award Number:B14041Fundamental Research Funds for the Central Universities,Grant/Award Num bers:GK202103106,GK202103113+6 种基金Innovative Research Team,Grant/Award Number:IRT_14R33National Natural Science Foundation of China,Grant/Award Number:61975106National Universi ty Research Fund,Grant/Award Number:GK 261001009ShanXi Science and Technology Department,Grant/Award Number:20201101012Strategic Prionity Research Program of Chinese Academy of Sciences,Grant/Award Number:XDA17040506Key project of N ational Natural Science Foundation of China,Grant/Award Number:U21A20102National Natural Science Foundation of China,Grant/.Award Num ber.62174103。
文摘The defects within perovskite films are the fatal roadblock limiting the performance of perovskite solar cells(PSCs).Herein,we develop a patching strategy to obtain high quality perovskite film using bifunctional trifuorophenylacetic acid(TFPA).Theoretical calculation and experiments reveal that the-COOH groups in TFPA effectively passivate the deep-energy-level defects of perovskite by combining with Pb clusters on the perovskite grain surfaces to enhance the efficiency of PSCs,and hydrophobic benzene groups containing fluorine in TFPA are exposed to improve the stability of PSCs.The power conversion effi-ciency(PCE)of PSCs with TFPA is enhanced from 22.95%to 24.56%.Most importantly,we successfully fabricated flexible PSCs using TFPA with the high PCE of 22.65%.The devices with TFPA maintain 93.22%of the initial efficiency MPP under continuous irradiation for 10.5 h,while the devices without TFPA only retain 82.22%of the initial efficiency under the same conditions for just 5 h.Meanwhile,the unsealed devices with TFPA hold 93.59%of the initial efficiency when stored in air for 3912 h.
文摘Dormancy or germination is an essential question that seed plants have to face.Under natural circumstances,seeds of plants usually maintain the status of dormancy until they meet the optimal condition to trigger the germination process(Finkelstein et al.,2008;Shu et al.,2015).However,things are different in agriculture,i.e.