INTRODUCTIONLeft ventricular aneurysm and ischemic mitral regurgitation are two of most common complications of acute myocardial infarction （AMI）. Combination of both these two fatal complications is not rare and th...INTRODUCTIONLeft ventricular aneurysm and ischemic mitral regurgitation are two of most common complications of acute myocardial infarction （AMI）. Combination of both these two fatal complications is not rare and the management of these complicated cases is always a challenge to cardiac surgeon because of its relatively high mortality. We reported a rare case of AMI in which a singlestage correction of mitral valve replacement with preservation of mitral apparatus, sequential left internal thoracic artery （ITA） grafting and Cooley＇s technique.展开更多
The petrochemical industry,one of the fastest-growing sectors,is projected to continue expanding in the coming years.As environmental regulations tighten and demand for cleaner production increases,the petrochemical i...The petrochemical industry,one of the fastest-growing sectors,is projected to continue expanding in the coming years.As environmental regulations tighten and demand for cleaner production increases,the petrochemical industry is compelled to adopt environmentally sustainable technologies and advanced wastewater treatment solutions.Petrochemical wastewater contains a range of pollutants,including petroleum hydrocarbons,emulsified oils,phenols,ammonia,sulfides,and other organic compounds.These contaminants often occur in complex physicochemical forms at discharge,posing significant environmental risks.Conventional biological and physicochemical treatments frequently fail to meet stringent discharge standards because of limited resilience to load fluctuations,restricted biodegradability,and secondary sludge generation.Advanced treatment has therefore become essential for petrochemical wastewater management.Among available options,adsorption,membrane separations,and advanced oxidation processes stand out for their performance.Adsorption excels at removing heavy metals and recalcitrant organics owing to diverse sorbent chemistries and operational simplicity.Membrane technologies achieve molecular-level selectivity with high water recovery potential.Catalytic ozonation effectively mineralizes refractory pollutants and enhances subsequent biodegradability.Current research highlights innovations in graphene-based adsorbents,ceramic nanofiltration membranes,and multifunctional catalysts that improve treatment efficiency,stability,and reusability.This review synthesizes recent advances in the deep treatment of petrochemical wastewater,outlines research priorities for evaluating the effectiveness of these technologies in oil-based wastewater management,and provides reference for research and application in this field.展开更多
A new combined soft switching technique and a novel topology of aeronautical static inverter with high frequency pulse dc link are proposed in this paper, namely an electrical isolated converter can realize soft swi...A new combined soft switching technique and a novel topology of aeronautical static inverter with high frequency pulse dc link are proposed in this paper, namely an electrical isolated converter can realize soft switching of two stage cascade converters. It lays technical foundation for high power density, high efficiency and low cost aeronautical static inverter. The operation and design approach of this topology are carefully analyzed and studied. The validity of this topology is verified by simulation and test.展开更多
The global use of pesticides has steadily increased in recent years to enhance food production and protection and prolonge its shelf life.Nevertheless,pesticide residues and their association with various human diseas...The global use of pesticides has steadily increased in recent years to enhance food production and protection and prolonge its shelf life.Nevertheless,pesticide residues and their association with various human diseases have raised concerns among the population,as the primary route of human exposure to pesticides is through food consumption.Consequently,removing pesticide residues from agricultural products and food is crucial for mitigating associated risks.Various treatments are employed to eliminate and degrade pesticide residues,with commonly used conventional techniques such as washing,peeling,and cooking being used.Additionally,emerging techniques such as ultrasound,ozone,electric current,plasma,and ultraviolet light have been applied to remove these residues.In this study,we systematically reviewed 38 articles to assess the efficacy of combined techniques for pesticide residue removal in food.The findings revealed that using combined techniques resulted in significantly higher levels of residue removal.Furthermore,combining emerging techniques with other treatments has demonstrated increased removal efficiency,significantly reducing the variability in the percentage range of residue removal.The synergistic use of ultrasound,ozone,and ultraviolet light techniques demonstrated a notably enhanced efficacy in removing pesticides,resulting in a higher elimination percentage.Among the 38 studies,12 exhibited substantially lower variability.Moreover,ultrasound emerged as the technique with the most significant synergistic effect when combined with other techniques,enhancing the overall efficiency of pesticide residue removal.Among the 12 studies with lower variability,9 incorporated ultrasound,4 ozone,and 3 ultraviolet light as part of the combined treatment.However,it is essential to note that conventional techniques also achieved considerable residue removal,even with more significant variability.This information can serve as valuable guidance for managers,decision-makers,and the public in effectively selecting appropriate techniques to eliminate pesticide residues from food before consumption or sale.展开更多
A series of nanosized Co/Zn/Mn/K composite catalysts for Fischer-Tropsch synthesis （FTS） were prepared by supercritical fluid drying （SCFD） method and common drying （CD） method. The nanosized cobalt-based cataly...A series of nanosized Co/Zn/Mn/K composite catalysts for Fischer-Tropsch synthesis （FTS） were prepared by supercritical fluid drying （SCFD） method and common drying （CD） method. The nanosized cobalt-based catalysts were characterized by XRD, TEM and BET techniques. Their catalytic performances were tested in a slurry-bed reactor under FTS reaction conditions. The drying and crystallization were carried out simultaneously during SCFD, therefore, the catalysts prepared by SCFD method have ideal structure and show the FTS performance superior to the others prepared by CD method. The FTS activity and selectivity were improved via adding Zn, Mn and K promoters, and less CH4 and CO2 as well as higher yield of C5＋ products were achieved. The optimal performance of a 92% CO conversion and a 65% C5＋ product yield was obtained over a catalyst with the component of Co/Zn/Mn/K = 100/50/10/7. Furthermore, the catalytic performance was studied under the conditions of liquid-phase and supercritical phase slurry-bed, and C5＋ product yield were 57.4% and 65.4%, respectively. In summary, better catalytic performance was obtained using the nanosized catalyst prepared by SCFD method under supercritical reaction conditions, resulting in higher conversion of CO, less CO2 byproduct, and higher yield of C5＋ products.展开更多
This paper develops a quadratic function convex approximation approach to deal with the negative definite problem of the quadratic function induced by stability analysis of linear systems with time-varying delays.By i...This paper develops a quadratic function convex approximation approach to deal with the negative definite problem of the quadratic function induced by stability analysis of linear systems with time-varying delays.By introducing two adjustable parameters and two free variables,a novel convex function greater than or equal to the quadratic function is constructed,regardless of the sign of the coefficient in the quadratic term.The developed lemma can also be degenerated into the existing quadratic function negative-determination(QFND)lemma and relaxed QFND lemma respectively,by setting two adjustable parameters and two free variables as some particular values.Moreover,for a linear system with time-varying delays,a relaxed stability criterion is established via our developed lemma,together with the quivalent reciprocal combination technique and the Bessel-Legendre inequality.As a result,the conservatism can be reduced via the proposed approach in the context of constructing Lyapunov-Krasovskii functionals for the stability analysis of linear time-varying delay systems.Finally,the superiority of our results is illustrated through three numerical examples.展开更多
The Domain Decomposition Method(DDM) is a powerful approach to solving maily types of PDE's. DDM is especially suitable for massively Parallel computers. In the past, most research on DDM has focused on the domain...The Domain Decomposition Method(DDM) is a powerful approach to solving maily types of PDE's. DDM is especially suitable for massively Parallel computers. In the past, most research on DDM has focused on the domain splitting technique. In this paper. we focus our attention on use of a combination of techniques to solve each subproblem. The central question with DDM is that of how to doal with the pseodoboundary conditions. Here, we introduce a set of operators which act on the pseudo-boundaries in the solution process, referring to this new. procedure as the 'Generalized Domain Decomposition A.Jlethod(GDDM).' We have already obtained convergence factors for GDDM with certain classes of PDE's. These ctonvergence factors show that we can derive exact solutions of the whole problem for certain types of PDE's, and can get superior speed of convergence for other types.展开更多
Great Animation not just drawing sequence of images or just combining images into frame by frame whatever motion will be, but Great Animation actually based on Physics, Biology and Lip sync. 2D Animation Hybrid Techni...Great Animation not just drawing sequence of images or just combining images into frame by frame whatever motion will be, but Great Animation actually based on Physics, Biology and Lip sync. 2D Animation Hybrid Technique is combination of Traditional Technique and Digital Technique, but the motion also based on analytical motion and physics. Traditional technique using mostly stop motion technique and experiment in any material animated objects, such as celluloid, sand, pebble, clay, doll, flour, or any objects that can be animated. This day digital technique is widely used mostly using computer hardware and software, and a lot of 2D animation software out there that can be used to create 2D animation. 2D Animation Hybrid Technique is a new technique that combining the traditional 2D animation technique but not using stop motion technique and with digital technique using computer and software, this technique become possible using image scanning technology that can digitizing any image from photo to hand drawn image. Then the sequence hand drawn animation edited in frame by frame also layer by layer using certain software in computer to create illusion of motion. The motion itself not just using any sense of art but also using physics, biology especially anatomy when needed to create such realism motion or perhaps funny motion in cartoon style animation.展开更多
[Objectives]The extraction conditions of formula oolong tea were investigated by an orthogonal experiment.[Methods]The technical conditions were optimized by the 4C method,and the application of formula oolong tea ext...[Objectives]The extraction conditions of formula oolong tea were investigated by an orthogonal experiment.[Methods]The technical conditions were optimized by the 4C method,and the application of formula oolong tea extract in cigarettes was studied.[Results]①In the experimental range,the best sensory evaluation effect of formula oolong tea extract was obtained with extraction conditions of 70%ethanol as extraction solvent,extraction time h,extraction temperature 25℃,and ultrasonic frequency 80 kHz,and follow-up low-temperature concentration,low-temperature sedimentation and low-temperature centrifugation.②The effects of different centrifugal speeds on the quality of formula oolong tea extract were explored.The formula oolong tea extract obtained under the conditions of 3000 r/min and centrifugal time of 10 min showed the best evaluation effect with soft and delicate smoke,rich smoke fragrance,good comfort and refreshing mouthfeel.③The effective aroma components in the formula oolong tea extract were qualitatively analyzed by GC-MS.[Conclusions]This study provides high-quality raw materials and a theoretical basis for the research of independent flavor blending in cigarette industry enterprises.展开更多
Constructing surface-enhanced Raman scattering(SERS)substrates is a recognized and effective approach for amplifying Raman signals.However,the simultaneous acquisition of nanostructured substrates with high enhancemen...Constructing surface-enhanced Raman scattering(SERS)substrates is a recognized and effective approach for amplifying Raman signals.However,the simultaneous acquisition of nanostructured substrates with high enhancement factors and repeatability poses challenges due to cost and technological limitations.Here,we developed nanometer-spaced metal gratings(NSMGs)with high sensitivity and uniformity for SERS applications by combining nanoimprint techniques with a flexible polydimethylsiloxane(PDMS)substrate.The grating spacing of NSMGs could be adjusted by capitalizing on the stretchability of PDMS,resulting in the acquisition of SERS gratings with different nano-sized gaps(minimum~22 nm)under a single imprinting mold with wide spacing.Importantly,the hotspots on the substrate can be flexibly tailored by the spacing adjustment,leading to the further enhancement of SERS signal,maximum up to nine-fold.Besides,the target molecule could be easily squeezed into the metal gaps with a strong localized electromagnetic field through active stretching and releasing of the substrate,which can further amplify the SERS signal.The high sensitivity and versatility of NSMGs were further proved by the label-free detection of rhodamine 6G(R6G)and adenine at nanomolar level.The proposed NSMG substrate is cost-effective and can be mass-produced,which has great potential for SERS applications.展开更多
Synchrotron radiation based combined technique can provide multiple structural information simultaneously,which is an important development direction of structural detection.In this study,a novel small-angle X-ray sca...Synchrotron radiation based combined technique can provide multiple structural information simultaneously,which is an important development direction of structural detection.In this study,a novel small-angle X-ray scattering/X-ray diffraction/X-ray absorption fine structure(SAXS/XRD/XAFS)combined setup was constructed,where an area detector,a curved detector,and a point detector are,respectively,used for the measurements of SAXS,XRD,and XAFS signals.A detailed description about the combined setup was given.A minitype diamond detector coupled to a SAXS beamstop was used to record the transmitted X-ray intensity,making the scattering(SAXS and XRD)signal measurement compatible with the absorption(XAFS)signal measurement,avoiding mechanical switching.The two-way sampling strategy was used to acquire XAFS signals,shortening the non-counting time.The two-way and one-way sampling strategies were discussed.High-frequency sampling scheme was used to collect experimental signals,improving the measurement efficiency and signal-to-noise ratio.A detailed description and discussion about the high-frequency scheme were also given in this paper.Except the rotation of monochromator,there is no mechanical movement in measurements,time resolution may reach the level of seconds.Using this SAXS/XRD/XAFS combined setup,SAXS,XRD,and XAFS signals can be acquired simultaneously.With some in-situ sample environment system,the newlydeveloped combined technique can be used to track the structure evolution in complex fluids.During the formation processes of(BiO)2CO3 and ZnAPO-34 particles,the changes of in-situ experimental data with reaction time demonstrate that SAXS/XRD/XAFS combined technique is feasible to track the dynamic process.展开更多
The synthetic path of a catalyst determines its morphology,species,and performance,and in-situ monitoring the catalyst formation process is fascinating and challenging.Herein,a newly developed synchrotron radiation sm...The synthetic path of a catalyst determines its morphology,species,and performance,and in-situ monitoring the catalyst formation process is fascinating and challenging.Herein,a newly developed synchrotron radiation smallangle X-ray scattering/X-ray diffraction/X-ray absorption fine structure(SAXS/XRD/XAFS)combined technique was used to in-situ monitor the isothermal-isobaric synthesis process of CO_(2)-assisted(BiO)_(2)CO_(3)(BOC)photocatalyst,and the atomic near-neighbor structure,crystalline structure and nanoscale particle size evolution with reaction time were simultaneously captured.The results show that both polyvinyl pyrrolidone and CO_(2)formed uniformly-distributed nano-sized scatterers in the Bi-based precursor solution,presenting short-range ordered structures to a certain extent.The as-prepared BOC catalytic particles underwent the evolution process of initial Bi(OH)3 precipitate,early-stage formed KBiO_(2)molecules,intermediate amorphous(BiO)4CO3(OH)2 nanoparticles,and finally crystallized flower-like BOC particles self-assembled by nanosheets.The flower-like BOC particles,Bi/BOC composite,and Bi nanospheres were further prepared with different synthesis paths.Flower-like BOC particles showed the best photocatalytic degradation performance of RhB.Scavenger experiment and theoretical calculation revealed the photocatalytic mechanisms of BOC.This work has implications for path-dependent synthesis of other catalysts.展开更多
One goal of financial research is to determine fair prices on the financial market.As financial models and the data sets on which they are based are becoming ever larger and thus more complex,financial instruments mus...One goal of financial research is to determine fair prices on the financial market.As financial models and the data sets on which they are based are becoming ever larger and thus more complex,financial instruments must be further developed to adapt to the new complexity,with short runtimes and efficient use of memory space.Here we show the effects of combining known strategies and incorporating new ideas to further improve numerical techniques in computational finance.In this paper we combine an ADI(alternating direction implicit)scheme for the temporal discretization with a sparse grid approach and the combination technique.The later approach considerably reduces the number of“spatial”grid points.The presented standard financial problem for the valuation of American options using the Heston model is chosen to illustrate the advantages of our approach,since it can easily be adapted to other more complex models.展开更多
基金supported by grants National Dis-tinguished Youth Science Fund (No.30525020)
文摘INTRODUCTIONLeft ventricular aneurysm and ischemic mitral regurgitation are two of most common complications of acute myocardial infarction （AMI）. Combination of both these two fatal complications is not rare and the management of these complicated cases is always a challenge to cardiac surgeon because of its relatively high mortality. We reported a rare case of AMI in which a singlestage correction of mitral valve replacement with preservation of mitral apparatus, sequential left internal thoracic artery （ITA） grafting and Cooley＇s technique.
基金supported by the National Natural Science Foundation of China(22172068)the International Industrial Technology Research and Development Project of Liaoning Province(2025JH2/101900006)the Science and Technology Innovation Teams of the Talent Revi-talization Program of Liaoning Province(XLYC2404022).
文摘The petrochemical industry,one of the fastest-growing sectors,is projected to continue expanding in the coming years.As environmental regulations tighten and demand for cleaner production increases,the petrochemical industry is compelled to adopt environmentally sustainable technologies and advanced wastewater treatment solutions.Petrochemical wastewater contains a range of pollutants,including petroleum hydrocarbons,emulsified oils,phenols,ammonia,sulfides,and other organic compounds.These contaminants often occur in complex physicochemical forms at discharge,posing significant environmental risks.Conventional biological and physicochemical treatments frequently fail to meet stringent discharge standards because of limited resilience to load fluctuations,restricted biodegradability,and secondary sludge generation.Advanced treatment has therefore become essential for petrochemical wastewater management.Among available options,adsorption,membrane separations,and advanced oxidation processes stand out for their performance.Adsorption excels at removing heavy metals and recalcitrant organics owing to diverse sorbent chemistries and operational simplicity.Membrane technologies achieve molecular-level selectivity with high water recovery potential.Catalytic ozonation effectively mineralizes refractory pollutants and enhances subsequent biodegradability.Current research highlights innovations in graphene-based adsorbents,ceramic nanofiltration membranes,and multifunctional catalysts that improve treatment efficiency,stability,and reusability.This review synthesizes recent advances in the deep treatment of petrochemical wastewater,outlines research priorities for evaluating the effectiveness of these technologies in oil-based wastewater management,and provides reference for research and application in this field.
文摘A new combined soft switching technique and a novel topology of aeronautical static inverter with high frequency pulse dc link are proposed in this paper, namely an electrical isolated converter can realize soft switching of two stage cascade converters. It lays technical foundation for high power density, high efficiency and low cost aeronautical static inverter. The operation and design approach of this topology are carefully analyzed and studied. The validity of this topology is verified by simulation and test.
基金Authors thank to the funding of Inter Transdisciplinary Research Support Fund 2024,DIPOG no 37175004-301-81.
文摘The global use of pesticides has steadily increased in recent years to enhance food production and protection and prolonge its shelf life.Nevertheless,pesticide residues and their association with various human diseases have raised concerns among the population,as the primary route of human exposure to pesticides is through food consumption.Consequently,removing pesticide residues from agricultural products and food is crucial for mitigating associated risks.Various treatments are employed to eliminate and degrade pesticide residues,with commonly used conventional techniques such as washing,peeling,and cooking being used.Additionally,emerging techniques such as ultrasound,ozone,electric current,plasma,and ultraviolet light have been applied to remove these residues.In this study,we systematically reviewed 38 articles to assess the efficacy of combined techniques for pesticide residue removal in food.The findings revealed that using combined techniques resulted in significantly higher levels of residue removal.Furthermore,combining emerging techniques with other treatments has demonstrated increased removal efficiency,significantly reducing the variability in the percentage range of residue removal.The synergistic use of ultrasound,ozone,and ultraviolet light techniques demonstrated a notably enhanced efficacy in removing pesticides,resulting in a higher elimination percentage.Among the 38 studies,12 exhibited substantially lower variability.Moreover,ultrasound emerged as the technique with the most significant synergistic effect when combined with other techniques,enhancing the overall efficiency of pesticide residue removal.Among the 12 studies with lower variability,9 incorporated ultrasound,4 ozone,and 3 ultraviolet light as part of the combined treatment.However,it is essential to note that conventional techniques also achieved considerable residue removal,even with more significant variability.This information can serve as valuable guidance for managers,decision-makers,and the public in effectively selecting appropriate techniques to eliminate pesticide residues from food before consumption or sale.
基金supported by Research Fund for the Doctoral Program of Higher Education (China,No.20050010014)
文摘A series of nanosized Co/Zn/Mn/K composite catalysts for Fischer-Tropsch synthesis （FTS） were prepared by supercritical fluid drying （SCFD） method and common drying （CD） method. The nanosized cobalt-based catalysts were characterized by XRD, TEM and BET techniques. Their catalytic performances were tested in a slurry-bed reactor under FTS reaction conditions. The drying and crystallization were carried out simultaneously during SCFD, therefore, the catalysts prepared by SCFD method have ideal structure and show the FTS performance superior to the others prepared by CD method. The FTS activity and selectivity were improved via adding Zn, Mn and K promoters, and less CH4 and CO2 as well as higher yield of C5＋ products were achieved. The optimal performance of a 92% CO conversion and a 65% C5＋ product yield was obtained over a catalyst with the component of Co/Zn/Mn/K = 100/50/10/7. Furthermore, the catalytic performance was studied under the conditions of liquid-phase and supercritical phase slurry-bed, and C5＋ product yield were 57.4% and 65.4%, respectively. In summary, better catalytic performance was obtained using the nanosized catalyst prepared by SCFD method under supercritical reaction conditions, resulting in higher conversion of CO, less CO2 byproduct, and higher yield of C5＋ products.
基金the National Natural Science Foundation of China(62273058,U22A2045)the Key Science and Technology Projects of Jilin Province(20200401075GX)the Youth Science and Technology Innovation and Entrepreneurship Outstanding Talents Project of Jilin Province(20230508043RC)。
文摘This paper develops a quadratic function convex approximation approach to deal with the negative definite problem of the quadratic function induced by stability analysis of linear systems with time-varying delays.By introducing two adjustable parameters and two free variables,a novel convex function greater than or equal to the quadratic function is constructed,regardless of the sign of the coefficient in the quadratic term.The developed lemma can also be degenerated into the existing quadratic function negative-determination(QFND)lemma and relaxed QFND lemma respectively,by setting two adjustable parameters and two free variables as some particular values.Moreover,for a linear system with time-varying delays,a relaxed stability criterion is established via our developed lemma,together with the quivalent reciprocal combination technique and the Bessel-Legendre inequality.As a result,the conservatism can be reduced via the proposed approach in the context of constructing Lyapunov-Krasovskii functionals for the stability analysis of linear time-varying delay systems.Finally,the superiority of our results is illustrated through three numerical examples.
文摘The Domain Decomposition Method(DDM) is a powerful approach to solving maily types of PDE's. DDM is especially suitable for massively Parallel computers. In the past, most research on DDM has focused on the domain splitting technique. In this paper. we focus our attention on use of a combination of techniques to solve each subproblem. The central question with DDM is that of how to doal with the pseodoboundary conditions. Here, we introduce a set of operators which act on the pseudo-boundaries in the solution process, referring to this new. procedure as the 'Generalized Domain Decomposition A.Jlethod(GDDM).' We have already obtained convergence factors for GDDM with certain classes of PDE's. These ctonvergence factors show that we can derive exact solutions of the whole problem for certain types of PDE's, and can get superior speed of convergence for other types.
文摘Great Animation not just drawing sequence of images or just combining images into frame by frame whatever motion will be, but Great Animation actually based on Physics, Biology and Lip sync. 2D Animation Hybrid Technique is combination of Traditional Technique and Digital Technique, but the motion also based on analytical motion and physics. Traditional technique using mostly stop motion technique and experiment in any material animated objects, such as celluloid, sand, pebble, clay, doll, flour, or any objects that can be animated. This day digital technique is widely used mostly using computer hardware and software, and a lot of 2D animation software out there that can be used to create 2D animation. 2D Animation Hybrid Technique is a new technique that combining the traditional 2D animation technique but not using stop motion technique and with digital technique using computer and software, this technique become possible using image scanning technology that can digitizing any image from photo to hand drawn image. Then the sequence hand drawn animation edited in frame by frame also layer by layer using certain software in computer to create illusion of motion. The motion itself not just using any sense of art but also using physics, biology especially anatomy when needed to create such realism motion or perhaps funny motion in cartoon style animation.
文摘[Objectives]The extraction conditions of formula oolong tea were investigated by an orthogonal experiment.[Methods]The technical conditions were optimized by the 4C method,and the application of formula oolong tea extract in cigarettes was studied.[Results]①In the experimental range,the best sensory evaluation effect of formula oolong tea extract was obtained with extraction conditions of 70%ethanol as extraction solvent,extraction time h,extraction temperature 25℃,and ultrasonic frequency 80 kHz,and follow-up low-temperature concentration,low-temperature sedimentation and low-temperature centrifugation.②The effects of different centrifugal speeds on the quality of formula oolong tea extract were explored.The formula oolong tea extract obtained under the conditions of 3000 r/min and centrifugal time of 10 min showed the best evaluation effect with soft and delicate smoke,rich smoke fragrance,good comfort and refreshing mouthfeel.③The effective aroma components in the formula oolong tea extract were qualitatively analyzed by GC-MS.[Conclusions]This study provides high-quality raw materials and a theoretical basis for the research of independent flavor blending in cigarette industry enterprises.
基金Guangdong Introducing Innovative and Enterpreneurial Teams of“The Pearl River Talent Recruitment Program”(2019ZT08X340)Guangzhou Basic and Applied Basic Research Foundation(2023A04J2043)+1 种基金Basic and Applied Basic Research Foundation of Guangdong Province(2024A1515011728)National Natural Science Foundation of China(62275054,62175039)。
文摘Constructing surface-enhanced Raman scattering(SERS)substrates is a recognized and effective approach for amplifying Raman signals.However,the simultaneous acquisition of nanostructured substrates with high enhancement factors and repeatability poses challenges due to cost and technological limitations.Here,we developed nanometer-spaced metal gratings(NSMGs)with high sensitivity and uniformity for SERS applications by combining nanoimprint techniques with a flexible polydimethylsiloxane(PDMS)substrate.The grating spacing of NSMGs could be adjusted by capitalizing on the stretchability of PDMS,resulting in the acquisition of SERS gratings with different nano-sized gaps(minimum~22 nm)under a single imprinting mold with wide spacing.Importantly,the hotspots on the substrate can be flexibly tailored by the spacing adjustment,leading to the further enhancement of SERS signal,maximum up to nine-fold.Besides,the target molecule could be easily squeezed into the metal gaps with a strong localized electromagnetic field through active stretching and releasing of the substrate,which can further amplify the SERS signal.The high sensitivity and versatility of NSMGs were further proved by the label-free detection of rhodamine 6G(R6G)and adenine at nanomolar level.The proposed NSMG substrate is cost-effective and can be mass-produced,which has great potential for SERS applications.
基金This work was supported by the National Key Research and Development Program of China(Nos.2017YFA0403000 and 2017YFA0403100).
文摘Synchrotron radiation based combined technique can provide multiple structural information simultaneously,which is an important development direction of structural detection.In this study,a novel small-angle X-ray scattering/X-ray diffraction/X-ray absorption fine structure(SAXS/XRD/XAFS)combined setup was constructed,where an area detector,a curved detector,and a point detector are,respectively,used for the measurements of SAXS,XRD,and XAFS signals.A detailed description about the combined setup was given.A minitype diamond detector coupled to a SAXS beamstop was used to record the transmitted X-ray intensity,making the scattering(SAXS and XRD)signal measurement compatible with the absorption(XAFS)signal measurement,avoiding mechanical switching.The two-way sampling strategy was used to acquire XAFS signals,shortening the non-counting time.The two-way and one-way sampling strategies were discussed.High-frequency sampling scheme was used to collect experimental signals,improving the measurement efficiency and signal-to-noise ratio.A detailed description and discussion about the high-frequency scheme were also given in this paper.Except the rotation of monochromator,there is no mechanical movement in measurements,time resolution may reach the level of seconds.Using this SAXS/XRD/XAFS combined setup,SAXS,XRD,and XAFS signals can be acquired simultaneously.With some in-situ sample environment system,the newlydeveloped combined technique can be used to track the structure evolution in complex fluids.During the formation processes of(BiO)2CO3 and ZnAPO-34 particles,the changes of in-situ experimental data with reaction time demonstrate that SAXS/XRD/XAFS combined technique is feasible to track the dynamic process.
基金supported by the National Natural Science Foundation of China(12305372)the National Key R&D Program(2017YFA0403001 and 2022YFA1603802)of China。
文摘The synthetic path of a catalyst determines its morphology,species,and performance,and in-situ monitoring the catalyst formation process is fascinating and challenging.Herein,a newly developed synchrotron radiation smallangle X-ray scattering/X-ray diffraction/X-ray absorption fine structure(SAXS/XRD/XAFS)combined technique was used to in-situ monitor the isothermal-isobaric synthesis process of CO_(2)-assisted(BiO)_(2)CO_(3)(BOC)photocatalyst,and the atomic near-neighbor structure,crystalline structure and nanoscale particle size evolution with reaction time were simultaneously captured.The results show that both polyvinyl pyrrolidone and CO_(2)formed uniformly-distributed nano-sized scatterers in the Bi-based precursor solution,presenting short-range ordered structures to a certain extent.The as-prepared BOC catalytic particles underwent the evolution process of initial Bi(OH)3 precipitate,early-stage formed KBiO_(2)molecules,intermediate amorphous(BiO)4CO3(OH)2 nanoparticles,and finally crystallized flower-like BOC particles self-assembled by nanosheets.The flower-like BOC particles,Bi/BOC composite,and Bi nanospheres were further prepared with different synthesis paths.Flower-like BOC particles showed the best photocatalytic degradation performance of RhB.Scavenger experiment and theoretical calculation revealed the photocatalytic mechanisms of BOC.This work has implications for path-dependent synthesis of other catalysts.
基金supported by the bilateral German-Slovakian Project MATTHIAS–Modelling and Approximation Tools and Techniques for Hamilton-Jacobi-Bellman equations in finance and Innovative Approach to their Solution,financed by DAAD and the Slovakian Ministry of Education.Further the authors acknowledge partial support from the bilateral German-Portuguese Project FRACTAL–FRActional models and CompuTationAL Finance financed by DAAD and the CRUP–Conselho de Reitores das Universidades Portuguesas.
文摘One goal of financial research is to determine fair prices on the financial market.As financial models and the data sets on which they are based are becoming ever larger and thus more complex,financial instruments must be further developed to adapt to the new complexity,with short runtimes and efficient use of memory space.Here we show the effects of combining known strategies and incorporating new ideas to further improve numerical techniques in computational finance.In this paper we combine an ADI(alternating direction implicit)scheme for the temporal discretization with a sparse grid approach and the combination technique.The later approach considerably reduces the number of“spatial”grid points.The presented standard financial problem for the valuation of American options using the Heston model is chosen to illustrate the advantages of our approach,since it can easily be adapted to other more complex models.
