We investigated erosion-corrosion(E-C) and its mitigation on the internal surface of the expansion segment of N80 steel tube in a loop system using array electrode technique, weight-loss measurement, computational-flu...We investigated erosion-corrosion(E-C) and its mitigation on the internal surface of the expansion segment of N80 steel tube in a loop system using array electrode technique, weight-loss measurement, computational-fluid-dynamics simulation, and surface characterization techniques.The results show that high E-C rates can occur at locations where there is a high flow velocity and/or a strong impact from sand particles, which results in different E-C rates at various locations.Consequently, it can be expected that localized corrosion often occurs in such segments.The E-C rate at each location in the expansion segment can be significantly mitigated with an imidazoline derivative inhibitor, as the resulting inhibitor layer significantly impedes the electrochemical reaction rate.However, we found that this inhibitor layer could not effectively reduce the difference in the erosion rates at different locations on the internal surface of the expansion segment.This means that localized corrosion can still occur at the expansion segment despite the presence of the inhibitor.展开更多
This paper presents a probabilistic model of cumulative damage based on Markov chains theory to model propagation of internal corrosion depth localized in a hydrocarbons transport pipeline. The damage accumulation mec...This paper presents a probabilistic model of cumulative damage based on Markov chains theory to model propagation of internal corrosion depth localized in a hydrocarbons transport pipeline. The damage accumulation mechanism is unit jump type, depending on the state. It uses a shock model based on Bernoulli trials and probabilities to remain in the same state or the next one. Data are adjusted to Lognormal distribution and proven with a Kolmogórov-Smirnov test. The vector obtained from multiplying the initial state vector with the transition matrix was developed and the system of equations to find each transition probability with a single inspection report was solved. In order to calculate propagation of internal corrosion after inspection, an exponential equation was proposed and a parameter was adjusted to the data. Time to expected failure was obtained by adding the time expected in each damage state. Each time step was adjusted to real time.展开更多
Based on a special transformation that we introduce,the N-soliton solution of the(2+1)-dimensional Boiti–Leon–Manna–Pempinelli equation is constructed.By applying the long wave limit and restricting certain conjuga...Based on a special transformation that we introduce,the N-soliton solution of the(2+1)-dimensional Boiti–Leon–Manna–Pempinelli equation is constructed.By applying the long wave limit and restricting certain conjugation conditions to the related solitons,some novel localized wave solutions are obtained,which contain higher-order breathers and lumps as well as their interactions.In particular,by choosing appropriate parameters involved in the N-solitons,two interaction solutions mixed by a bell-shaped soliton and one breather or by a bell-shaped soliton and one lump are constructed from the 3-soliton solution.Five solutions including two breathers,two lumps,and interaction solutions between one breather and two bell-shaped solitons,one breather and one lump,or one lump and two bell-shaped solitons are constructed from the4-soliton solution.Five interaction solutions mixed by one breather/lump and three bell-shaped solitons,two breathers/lumps and a bell-shaped soliton,as well as mixing with one lump,one breather and a bell-shaped soliton are constructed from the 5-soliton solution.To study the behaviors that the obtained interaction solutions may have,we present some illustrative numerical simulations,which demonstrate that the choice of the parameters has a great impacts on the types of the solutions and their propagation properties.The method proposed can be effectively used to construct localized interaction solutions of many nonlinear evolution equations.The results obtained may help related experts to understand and study the interaction phenomena of nonlinear localized waves during propagations.展开更多
The cluster-shaped plasmonic nanostructures are used to manage the incident light inside an ultra-thin silicon solar cell.Here we simulate spherical,conical,pyramidal,and cylindrical nanoparticles in a form of a clust...The cluster-shaped plasmonic nanostructures are used to manage the incident light inside an ultra-thin silicon solar cell.Here we simulate spherical,conical,pyramidal,and cylindrical nanoparticles in a form of a cluster at the rear side of a thin silicon cell,using the finite difference time domain(FDTD)method.By calculating the optical absorption and hence the photocurrent,it is shown that the clustering of nanoparticles significantly improves them.The photocurrent enhancement is the result of the plasmonic effects of clustering the nanoparticles.For comparison,first a cell with a single nanoparticle at the rear side is evaluated.Then four smaller nanoparticles are put around it to make a cluster.The photocurrents of 20.478 mA/cm2,23.186 mA/cm2,21.427 mA/cm2,and 21.243 mA/cm2 are obtained for the cells using clustering conical,spherical,pyramidal,cylindrical NPs at the backside,respectively.These values are 13.987 mA/cm2,16.901 mA/cm2,16.507 mA/cm2,17.926 mA/cm2 for the cell with one conical,spherical,pyramidal,cylindrical NPs at the backside,respectively.Therefore,clustering can significantly improve the photocurrents.Finally,the distribution of the electric field and the generation rate for the proposed structures are calculated.展开更多
The formation of shear bands in metallic glasses(MGs)was examined by tailoring localized complex stress fields(LCSFs).The findings have shown that the LCSFs in MGs can increase the localization of strained atoms and a...The formation of shear bands in metallic glasses(MGs)was examined by tailoring localized complex stress fields(LCSFs).The findings have shown that the LCSFs in MGs can increase the localization of strained atoms and accelerate the release of accumulated deformation energy for initiating a shear band in confined and thin-layered regions.The findings not only add more knowledge to the formation mechanisms of shear bands in MGs,but also provide possible rationale for the discrepancies in the mechanical properties of different-sized MGs.As compared with the bulk samples,the higher strength and larger elastic limits in nanoscaled MGs could be attributed to the elimination of stress-concentrators,which can serve as LCSFs.展开更多
A localized space-time method of fundamental solutions(LSTMFS)is extended for solving three-dimensional transient diffusion problems in this paper.The interval segmentation in temporal direction is developed for the a...A localized space-time method of fundamental solutions(LSTMFS)is extended for solving three-dimensional transient diffusion problems in this paper.The interval segmentation in temporal direction is developed for the accurate simulation of long-time-dependent diffusion problems.In the LSTMFS,the whole space-time domain with nodes arranged i divided into a series of overlapping subdomains with a simple geometry.In each subdomain,the conventional method of fundamental solutions is utilized and the coefficients associated with the considered domain can be explicitly determined.By calculating a combined sparse matrix system,the value at any node inside the space-time domain can be obtained.Numerical experi-ments demonstrate that high accuracy and efficiency can be simultaneously achieved via the LSTMFS,even for the problems defined on a long-time and quite complex computational domain.展开更多
Scanning electrochemical microscopy(SECM)and scanning vibrating electrode technique(SVET)were used to investigate the electrochemical behaviour of the top surface of the 2098-T351 alloy welded by friction stir welding...Scanning electrochemical microscopy(SECM)and scanning vibrating electrode technique(SVET)were used to investigate the electrochemical behaviour of the top surface of the 2098-T351 alloy welded by friction stir welding(FSW).The SVET technique was efficient in identifying the cathodic and anodic weld regions.The welding joint(WJ),which comprises the thermomechanically affected zone(TMAZ)and the stir zone(SZ),was cathodic relative to the heated affected zone(HAZ)and the base metal(BM).The reactivities of the welding joint at the advancing side(AS)and the retreating side(RS)were analyzed and compared using SECM technique in the competition mode by monitoring the dissolved oxygen as a redox mediator in 0.005 mol L^-1 NaCl solution.The RS was more electrochemically active than the AS,and these results were correlated with the microstructural features of the welded alloy.展开更多
The microstructure,localized corrosion (LC) and stress corrosion cracking (SCC) behavior of 7003 aluminum alloy (AA7003) under various aging treatments (peak aging (PA),double peak aging (DPA),regression and re-aging ...The microstructure,localized corrosion (LC) and stress corrosion cracking (SCC) behavior of 7003 aluminum alloy (AA7003) under various aging treatments (peak aging (PA),double peak aging (DPA),regression and re-aging (RRA)) were investigated by means of transmission electron microscope (TEM),scanning electron microscopy (SEM),electrochemical impendence spectroscopy (EIS) and slow strain rate tensile test.The results of TEM showed a discontinuous distribution of grain boundary precipitates of AA7003 under DPA and RRA treatments,which is beneficial for increasing the resistance of LC and SCC.Meanwhile,LC was found initiating firstly on intermetallics which caused the dissolution of surrounding matrix,then pitting holes were formed and developed into matrix.In addition,the SCC process of AA7003 could be divided into two stages,i e,initial pre-cracking and breeding cracking.The EIS analysis,cross-section morphologies and fracture surfaces of specimens indicated that DPA and RRA treatments significantly decreased the crack growth rate during breeding cracking stage,especially for RRA treatment.展开更多
NaBaPO4:Eu^2+,Er^3+phosphors and Ag nano-particles(NPs)were prepared by the solid-state reaction and chemical reduction method,respectively.The fluorescence spectra and decay curves demonstrate the effective energy tr...NaBaPO4:Eu^2+,Er^3+phosphors and Ag nano-particles(NPs)were prepared by the solid-state reaction and chemical reduction method,respectively.The fluorescence spectra and decay curves demonstrate the effective energy transfer from Eu^2+to Er^3+and the existence of three-photon quantum-cutting through two-step cross-relaxation of Er^3+.The quantum-cutting emission is peaked at 1534 nm with a broad excitation band centered at 352 nm,Plasmon-enhanced quantum-cutting of NaBaPO4:Eu^2+,Er^3+phosphors was realized by decorating Ag NPs.The largest enhancement factor is 1.395.It is hopeful to improve the photovoltaic conversion efficiency of Ge solar cells by using this phosphor.展开更多
Localized surface plasmonic resonance has attracted extensive attention since it allows for great enhancement of local field intensity on the nanoparticle surface.In this paper,we make a systematic study on the excita...Localized surface plasmonic resonance has attracted extensive attention since it allows for great enhancement of local field intensity on the nanoparticle surface.In this paper,we make a systematic study on the excitation of localized surface plasmons of a graphene coated dielectric particle.Theoretical results show that both the intensity and frequency of the plasmonic resonant peak can be tuned effectively through modifying the graphene layer.Furthermore,high order localized surface plasmons could be excited and tuned selectively by the Laguerre Gaussian beam,which is induced by the optical angular orbital momentum transfer through the mutual interaction between the particle and the helical wavefront.Moreover,the profiles of the multipolar localized surface plasmons are illustrated in detail.The study provides rich potential applications in the plasmonic devices and the wavefront engineering nano-optics.展开更多
Plasmonic photocatalysis represents the synergetic union of two active fields of research:plasmonic effects in illuminated metallic nanoparticles and catalytic effects in tailored metallic nanoparticles.Traditionally,...Plasmonic photocatalysis represents the synergetic union of two active fields of research:plasmonic effects in illuminated metallic nanoparticles and catalytic effects in tailored metallic nanoparticles.Traditionally,metallic nanoparticles that excel for one application are limited for the other,but recent developments have shown that desirable catalytic behaviors,such as reduced activation barriers and improved product selectivity,derive from nonthermal behaviors uniquely produced by this synergy.After examining such findings,this review will address a specific debate that has recently surfaced:what is the relative degree of contributions of thermal and nonthermal effects in plasmonic photocatalysis?We demonstrate the importance of correctly accounting for thermal effects before characterizing nonthermal contributions.We show that another synergy occurs:these desirable nonthermal behaviors have a temperature dependence,and the resulting temperature-dependent reaction rates far exceed what can be explained from purely thermal effects alone.Thus,the synergy of plasmonic photocatalysis offers an exciting new contribution to the quest for efficient,selective,sustainable methods for chemical synthesis and energy conversion.展开更多
The corrosion behaviour of mill-scaled X65 pipeline steel with and without a primer layer was studied in a simulated near-neutral pH soil solution.Results revealed a three-stage corrosion process of the mill-scaled pi...The corrosion behaviour of mill-scaled X65 pipeline steel with and without a primer layer was studied in a simulated near-neutral pH soil solution.Results revealed a three-stage corrosion process of the mill-scaled pipeline steel surface.The first stage included an initial preferential dissolution of goethite(γ-FeOOH)and lepidocrocite(?-FeOOH)in mill scale.The second stage was marked by enhanced localized corrosion and pit-formation because of either galvanic corrosion or acidic dissolution in areas enclosed by mill scale.The final stage was general corrosion after the mill scale flaked off the steel surface.When the primer layer was applied,localized corrosion was significantly enhanced on the steel surface and persisted for an extended period as compared to the mill-scaled condition.The precipitation of siderite(FeCO3)was observed at flawed locations of mill scale,although the bulk chemistry is not favorable for its formation on the steel surface free of mill scale.The local precipitation of siderite formed a capped mill scale enclosure where localized corrosion can be further enhanced.展开更多
Background Juvenile localized scleroderma(JLS)is a rare pediatric disease characterized by inflammation and skin thick ening.JLS is associated with deep tissue and extracutaneous involvement that often results in func...Background Juvenile localized scleroderma(JLS)is a rare pediatric disease characterized by inflammation and skin thick ening.JLS is associated with deep tissue and extracutaneous involvement that often results in functional impairment and growth disturbances.This article provides an overview of the disease with a focus on active features and treatment.Data sources We searched databases including PubMed,Elsevier and MedLine and Wanfang,reviewing publications from 2013 to 2019.Selected earlier publications were also reviewed.Results Linear scleroderma is the most common JLS subtype.Several lines of evidence suggest that JLS is an autoimmune disease.Extracutaneous involvement is common and can present before the onset of skin disease.Multiple skin features are associated with disease activity,and activity can also manifest as arthritis,myositis,uveitis,seizures,and growth impairment.Systemic immunosuppressive treatment,commonly methotrexate with or without glucocorticoids,greatly improves outcome and is recommended for treating JLS patients with active disease and moderate or higher severity.Long term monitoring is needed because of the disease's chronicity and the high frequency of relapses off of treatment.Conclusions JLS is associated with a risk for disabling and disfiguring morbidity for the growing child.Identifying active disease is important for guiding treatment,but often difficult because of the paucity of markers and lack of a universal skin activity feature.More studies of JLS pathophysiology are needed to allow the identification of biomarkers and therapeutic targets.Comparative effectiveness treatment studies are also needed to work towards optimizing care and outcome.展开更多
基金financially supported by the 111 Project (No.D18016)the Application and Fundamental Research of Sichuan Province, China (No.2017JY0171)the Scientific and Technological Innovation Team for the Safety of Petroleum Tubular Goods in Southwest Petroleum University (No.2018CXTD01)。
文摘We investigated erosion-corrosion(E-C) and its mitigation on the internal surface of the expansion segment of N80 steel tube in a loop system using array electrode technique, weight-loss measurement, computational-fluid-dynamics simulation, and surface characterization techniques.The results show that high E-C rates can occur at locations where there is a high flow velocity and/or a strong impact from sand particles, which results in different E-C rates at various locations.Consequently, it can be expected that localized corrosion often occurs in such segments.The E-C rate at each location in the expansion segment can be significantly mitigated with an imidazoline derivative inhibitor, as the resulting inhibitor layer significantly impedes the electrochemical reaction rate.However, we found that this inhibitor layer could not effectively reduce the difference in the erosion rates at different locations on the internal surface of the expansion segment.This means that localized corrosion can still occur at the expansion segment despite the presence of the inhibitor.
文摘This paper presents a probabilistic model of cumulative damage based on Markov chains theory to model propagation of internal corrosion depth localized in a hydrocarbons transport pipeline. The damage accumulation mechanism is unit jump type, depending on the state. It uses a shock model based on Bernoulli trials and probabilities to remain in the same state or the next one. Data are adjusted to Lognormal distribution and proven with a Kolmogórov-Smirnov test. The vector obtained from multiplying the initial state vector with the transition matrix was developed and the system of equations to find each transition probability with a single inspection report was solved. In order to calculate propagation of internal corrosion after inspection, an exponential equation was proposed and a parameter was adjusted to the data. Time to expected failure was obtained by adding the time expected in each damage state. Each time step was adjusted to real time.
基金supported by the National Natural Science Foundation of China under grant No.11775116Jiangsu Qinglan highlevel talent Project。
文摘Based on a special transformation that we introduce,the N-soliton solution of the(2+1)-dimensional Boiti–Leon–Manna–Pempinelli equation is constructed.By applying the long wave limit and restricting certain conjugation conditions to the related solitons,some novel localized wave solutions are obtained,which contain higher-order breathers and lumps as well as their interactions.In particular,by choosing appropriate parameters involved in the N-solitons,two interaction solutions mixed by a bell-shaped soliton and one breather or by a bell-shaped soliton and one lump are constructed from the 3-soliton solution.Five solutions including two breathers,two lumps,and interaction solutions between one breather and two bell-shaped solitons,one breather and one lump,or one lump and two bell-shaped solitons are constructed from the4-soliton solution.Five interaction solutions mixed by one breather/lump and three bell-shaped solitons,two breathers/lumps and a bell-shaped soliton,as well as mixing with one lump,one breather and a bell-shaped soliton are constructed from the 5-soliton solution.To study the behaviors that the obtained interaction solutions may have,we present some illustrative numerical simulations,which demonstrate that the choice of the parameters has a great impacts on the types of the solutions and their propagation properties.The method proposed can be effectively used to construct localized interaction solutions of many nonlinear evolution equations.The results obtained may help related experts to understand and study the interaction phenomena of nonlinear localized waves during propagations.
文摘The cluster-shaped plasmonic nanostructures are used to manage the incident light inside an ultra-thin silicon solar cell.Here we simulate spherical,conical,pyramidal,and cylindrical nanoparticles in a form of a cluster at the rear side of a thin silicon cell,using the finite difference time domain(FDTD)method.By calculating the optical absorption and hence the photocurrent,it is shown that the clustering of nanoparticles significantly improves them.The photocurrent enhancement is the result of the plasmonic effects of clustering the nanoparticles.For comparison,first a cell with a single nanoparticle at the rear side is evaluated.Then four smaller nanoparticles are put around it to make a cluster.The photocurrents of 20.478 mA/cm2,23.186 mA/cm2,21.427 mA/cm2,and 21.243 mA/cm2 are obtained for the cells using clustering conical,spherical,pyramidal,cylindrical NPs at the backside,respectively.These values are 13.987 mA/cm2,16.901 mA/cm2,16.507 mA/cm2,17.926 mA/cm2 for the cell with one conical,spherical,pyramidal,cylindrical NPs at the backside,respectively.Therefore,clustering can significantly improve the photocurrents.Finally,the distribution of the electric field and the generation rate for the proposed structures are calculated.
基金financially supported by the National Natural Science Foundation of China(Nos.51801049 and 51801174)the State Key Laboratory of Metastable Materials Science and Technology,Yanshan University(No.201809)the Fundamental Research Funds for the Central Universities of China(Nos.PA2019GDZC0096 and JD2019JGPY0015)。
文摘The formation of shear bands in metallic glasses(MGs)was examined by tailoring localized complex stress fields(LCSFs).The findings have shown that the LCSFs in MGs can increase the localization of strained atoms and accelerate the release of accumulated deformation energy for initiating a shear band in confined and thin-layered regions.The findings not only add more knowledge to the formation mechanisms of shear bands in MGs,but also provide possible rationale for the discrepancies in the mechanical properties of different-sized MGs.As compared with the bulk samples,the higher strength and larger elastic limits in nanoscaled MGs could be attributed to the elimination of stress-concentrators,which can serve as LCSFs.
基金the Fundamental Research Funds for the Central Universities(Grants B200203009 and B200202126)the Natural Science Foundation of Jiangsu Province(Grant BK20190073)+2 种基金the State Key Laboratory of Acoustics,Chinese Academy of Sciences(Grant SKLA202001)the State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,Shijiazhuang Tiedao University(Grant KF2020-22)the China Postdoctoral Science Foundation(Grants 2017M611669 and 2018T110430).
文摘A localized space-time method of fundamental solutions(LSTMFS)is extended for solving three-dimensional transient diffusion problems in this paper.The interval segmentation in temporal direction is developed for the accurate simulation of long-time-dependent diffusion problems.In the LSTMFS,the whole space-time domain with nodes arranged i divided into a series of overlapping subdomains with a simple geometry.In each subdomain,the conventional method of fundamental solutions is utilized and the coefficients associated with the considered domain can be explicitly determined.By calculating a combined sparse matrix system,the value at any node inside the space-time domain can be obtained.Numerical experi-ments demonstrate that high accuracy and efficiency can be simultaneously achieved via the LSTMFS,even for the problems defined on a long-time and quite complex computational domain.
基金CAPES(Capes/Cofecub N°80614)FAPESP(2013/13235-6)for financial support for this work+1 种基金CAPES PROEX for the grants of M.X.Milagre(88882.333479/2019-01),C.S.C.Machado(88882.333459/201901)FAPESP for the grants of U.Donatus(Proc.2017/03095-3)and R.Silva(Proc.2018/06880-6)。
文摘Scanning electrochemical microscopy(SECM)and scanning vibrating electrode technique(SVET)were used to investigate the electrochemical behaviour of the top surface of the 2098-T351 alloy welded by friction stir welding(FSW).The SVET technique was efficient in identifying the cathodic and anodic weld regions.The welding joint(WJ),which comprises the thermomechanically affected zone(TMAZ)and the stir zone(SZ),was cathodic relative to the heated affected zone(HAZ)and the base metal(BM).The reactivities of the welding joint at the advancing side(AS)and the retreating side(RS)were analyzed and compared using SECM technique in the competition mode by monitoring the dissolved oxygen as a redox mediator in 0.005 mol L^-1 NaCl solution.The RS was more electrochemically active than the AS,and these results were correlated with the microstructural features of the welded alloy.
基金Funded by National Natural Science Foundation of China(Nos.51371039 and 51871031)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘The microstructure,localized corrosion (LC) and stress corrosion cracking (SCC) behavior of 7003 aluminum alloy (AA7003) under various aging treatments (peak aging (PA),double peak aging (DPA),regression and re-aging (RRA)) were investigated by means of transmission electron microscope (TEM),scanning electron microscopy (SEM),electrochemical impendence spectroscopy (EIS) and slow strain rate tensile test.The results of TEM showed a discontinuous distribution of grain boundary precipitates of AA7003 under DPA and RRA treatments,which is beneficial for increasing the resistance of LC and SCC.Meanwhile,LC was found initiating firstly on intermetallics which caused the dissolution of surrounding matrix,then pitting holes were formed and developed into matrix.In addition,the SCC process of AA7003 could be divided into two stages,i e,initial pre-cracking and breeding cracking.The EIS analysis,cross-section morphologies and fracture surfaces of specimens indicated that DPA and RRA treatments significantly decreased the crack growth rate during breeding cracking stage,especially for RRA treatment.
基金Project supported by the National Natural Science Foundation of China(11204039,51202033)the Natural Science Foundation of Fujian Province of China(2017I01399,2017I01677,2019I01283)。
文摘NaBaPO4:Eu^2+,Er^3+phosphors and Ag nano-particles(NPs)were prepared by the solid-state reaction and chemical reduction method,respectively.The fluorescence spectra and decay curves demonstrate the effective energy transfer from Eu^2+to Er^3+and the existence of three-photon quantum-cutting through two-step cross-relaxation of Er^3+.The quantum-cutting emission is peaked at 1534 nm with a broad excitation band centered at 352 nm,Plasmon-enhanced quantum-cutting of NaBaPO4:Eu^2+,Er^3+phosphors was realized by decorating Ag NPs.The largest enhancement factor is 1.395.It is hopeful to improve the photovoltaic conversion efficiency of Ge solar cells by using this phosphor.
文摘Localized surface plasmonic resonance has attracted extensive attention since it allows for great enhancement of local field intensity on the nanoparticle surface.In this paper,we make a systematic study on the excitation of localized surface plasmons of a graphene coated dielectric particle.Theoretical results show that both the intensity and frequency of the plasmonic resonant peak can be tuned effectively through modifying the graphene layer.Furthermore,high order localized surface plasmons could be excited and tuned selectively by the Laguerre Gaussian beam,which is induced by the optical angular orbital momentum transfer through the mutual interaction between the particle and the helical wavefront.Moreover,the profiles of the multipolar localized surface plasmons are illustrated in detail.The study provides rich potential applications in the plasmonic devices and the wavefront engineering nano-optics.
基金The authors thank Dr.Xiao Zhang,Dr Matthew E.Reish,and Professor Weitao Yang for their valuable contributions to this work.Work at Duke was supported in part by the National Science Foundation(CHE-1565657)and the Army Research Office(Award W911NF-15-1-0320).X.L.was supported by the Department of Defense(DoD)through the National Defense Science&Engineering Graduate Fellowship(NDSEG)Program.
文摘Plasmonic photocatalysis represents the synergetic union of two active fields of research:plasmonic effects in illuminated metallic nanoparticles and catalytic effects in tailored metallic nanoparticles.Traditionally,metallic nanoparticles that excel for one application are limited for the other,but recent developments have shown that desirable catalytic behaviors,such as reduced activation barriers and improved product selectivity,derive from nonthermal behaviors uniquely produced by this synergy.After examining such findings,this review will address a specific debate that has recently surfaced:what is the relative degree of contributions of thermal and nonthermal effects in plasmonic photocatalysis?We demonstrate the importance of correctly accounting for thermal effects before characterizing nonthermal contributions.We show that another synergy occurs:these desirable nonthermal behaviors have a temperature dependence,and the resulting temperature-dependent reaction rates far exceed what can be explained from purely thermal effects alone.Thus,the synergy of plasmonic photocatalysis offers an exciting new contribution to the quest for efficient,selective,sustainable methods for chemical synthesis and energy conversion.
基金TransCanada Pipelines LimitedEnbridge Pipelines Inc.+1 种基金Natural Science and Engineering Research Council of CanadaPipeline Research Council International for the financial support。
文摘The corrosion behaviour of mill-scaled X65 pipeline steel with and without a primer layer was studied in a simulated near-neutral pH soil solution.Results revealed a three-stage corrosion process of the mill-scaled pipeline steel surface.The first stage included an initial preferential dissolution of goethite(γ-FeOOH)and lepidocrocite(?-FeOOH)in mill scale.The second stage was marked by enhanced localized corrosion and pit-formation because of either galvanic corrosion or acidic dissolution in areas enclosed by mill scale.The final stage was general corrosion after the mill scale flaked off the steel surface.When the primer layer was applied,localized corrosion was significantly enhanced on the steel surface and persisted for an extended period as compared to the mill-scaled condition.The precipitation of siderite(FeCO3)was observed at flawed locations of mill scale,although the bulk chemistry is not favorable for its formation on the steel surface free of mill scale.The local precipitation of siderite formed a capped mill scale enclosure where localized corrosion can be further enhanced.
文摘Background Juvenile localized scleroderma(JLS)is a rare pediatric disease characterized by inflammation and skin thick ening.JLS is associated with deep tissue and extracutaneous involvement that often results in functional impairment and growth disturbances.This article provides an overview of the disease with a focus on active features and treatment.Data sources We searched databases including PubMed,Elsevier and MedLine and Wanfang,reviewing publications from 2013 to 2019.Selected earlier publications were also reviewed.Results Linear scleroderma is the most common JLS subtype.Several lines of evidence suggest that JLS is an autoimmune disease.Extracutaneous involvement is common and can present before the onset of skin disease.Multiple skin features are associated with disease activity,and activity can also manifest as arthritis,myositis,uveitis,seizures,and growth impairment.Systemic immunosuppressive treatment,commonly methotrexate with or without glucocorticoids,greatly improves outcome and is recommended for treating JLS patients with active disease and moderate or higher severity.Long term monitoring is needed because of the disease's chronicity and the high frequency of relapses off of treatment.Conclusions JLS is associated with a risk for disabling and disfiguring morbidity for the growing child.Identifying active disease is important for guiding treatment,but often difficult because of the paucity of markers and lack of a universal skin activity feature.More studies of JLS pathophysiology are needed to allow the identification of biomarkers and therapeutic targets.Comparative effectiveness treatment studies are also needed to work towards optimizing care and outcome.