沙尘是中国北方典型的灾害天气。构建长时间尺度东亚地区高分辨率沙尘气溶胶质量浓度再分析数据集,是深化理解中国沙尘天气发生机理和提升多尺度预报水平的数据基础。受到风蚀起沙过程参数化方案、长距离输送误差等限制,当前沙尘模拟结...沙尘是中国北方典型的灾害天气。构建长时间尺度东亚地区高分辨率沙尘气溶胶质量浓度再分析数据集,是深化理解中国沙尘天气发生机理和提升多尺度预报水平的数据基础。受到风蚀起沙过程参数化方案、长距离输送误差等限制,当前沙尘模拟结果存在较大不确定性。鉴于此,本研究在前期开发的沙尘同化系统基础上,集成地面PM_(10)质量浓度、卫星气溶胶光学厚度(aerosol optical depth,AOD)观测非沙尘组分偏差校正技术,以及适用于沙尘气溶胶强度、位置误差协同校正的有效时刻偏移卡尔曼滤波同化算法(valid time shift ensemble Kalman filter,VTS-EnKF),建立了10 a(2014—2023年)东亚地区春季(3—5月)逐3 h的沙尘气溶胶三维质量浓度再分析数据集,分辨率为0.25°×0.25°。在此基础上,分析了所建立的再分析数据集相较于MERRA-2(modern-era retrospective analysis for research and applications version 2)沙尘再分析产品的优势,同时讨论了过去10 a东亚地区春季沙尘天气的月、年际变化趋势。展开更多
Heavy metal contamination is a global issue caused by anthropogenic activities leading to severe negative effects on the environment and human health.To address this problem,bioremediation strategies utilizing plants ...Heavy metal contamination is a global issue caused by anthropogenic activities leading to severe negative effects on the environment and human health.To address this problem,bioremediation strategies utilizing plants such as Typha latifolia and their symbiotic fungi have been adopted to remediate contaminated areas and mitigate the harmful effects of these pollutants.In this study,the endophytic fungus Neosartorya fischeri was isolated from the roots of T.latifolia plants growing in heavy metal-contaminated sites.N.fischeri colonized the epidermis and root cortex and showed high tolerance to toxic concentrations of silver(Ag)(1 mg/kg),copper(Cu)(60 mg/kg)and cadmium(Cd)(8 mg/kg).N.fischeri removed 8.7%±0.5%Cd from the medium,biosorbed 15.24±0.2 mg/kg into its biomass,and enhanced the tolerance and bioaccumulation of Cd(184.18±1.14 mg/kg)in plant roots.Moreover,N.fischeri produces siderophores,volatile compounds and solubilizes phosphates,which improve plant fitness.This was evidenced by a 28%increase in photosynthetic pigments in T.latifolia plants colonized with N.fischeri.Additionally,N.fischeri inhibits the growth of important phytopathogens from the Fusarium genus.These findings highlight the important role of N.fischeri in enhancing the fitness and resilience of T.latifolia in hostile environments,demonstrating the potential of N.fischeri-T.latifolia association for the bioremediation of contaminated sites.展开更多
The cultivation of Soledad pepper(Capsicum annuum L.)is essential in Oaxaca and Veracruz,but it faces issues with pests and diseases,which affect yield and cause economic losses.To mitigate these impacts,farmers have ...The cultivation of Soledad pepper(Capsicum annuum L.)is essential in Oaxaca and Veracruz,but it faces issues with pests and diseases,which affect yield and cause economic losses.To mitigate these impacts,farmers have started using biostimulants such as chitosan and plant growth promoting bacteria instead of agrochemicals due to their environmental and health benefits.This study evaluated the effect of Bacillus subtilis and chitosan,both individually and combined,on the growth,yield,and fruit quality of Soledad pepper under greenhouse conditions.Four treatments were applied at different stages of the crop cycle:Q(Chitosan),BS(Bacillus subtilis),Q+BS(Chitosan+Bacillus subtilis),and T(Control).The results showed that the combination of chitosan and Bacillus subtilis significantly improved plant growth,especially in height and stem diameter.The chitosan treatment produced the highest number of fruits and plant weight,while the combination of chitosan and Bacillus subtilis enhanced fruit quality,increasing characteristics such as size,weight,pericarp thickness,and physicochemical parameters,notably in brix degrees,citric acid percentage,and pH,outperforming the individual treatments and the control.展开更多
Utility-scale PV plants increasingly operate under partial shading,soiling,temperature swings,and rapid irradiance ramps that depress yield and challenge stability on weak grids.This critical review addresses those co...Utility-scale PV plants increasingly operate under partial shading,soiling,temperature swings,and rapid irradiance ramps that depress yield and challenge stability on weak grids.This critical review addresses those conditions by(i)unifying a stressor-to-method taxonomy that links field stressors to global intelligent MPPT(metaheuristics and learning-based trackers)and to advanced inverter controls(adaptive/MPC and grid-forming),(ii)standardizing metrics and reporting aligned with IEC 61724-1 and IEEE 1547/1547.1 to enable fair,reproducible comparisons,and(iii)framing MPPT and grid support as a co-design problem with a DT→HIL→Field validation pathway and seedable scenarios.We identify persistent gaps—fragmented partial-shading benchmarks,limited low-SCR testing,and scarce field-grade validation—and compile a quantitative synthesis:global soiling typically reduces annual production by≈3%–5%,and hybrid/learning MPPT frequently report≈99%tracking efficiency under PSC in simulation/HIL studies.To demonstrate practical relevance,we validate the framework on a seeded scenario library:DRL trackers achieve medianηMPPT≈0.996 with t95≈0.19 s and Hybrid trackers≈0.992/0.26 s,outperforming Metaheuristics(≈0.984/0.42 s);at SCR=2.5,grid-forming control raises VRI from~0.78(tuned GFL)to~0.95 while keeping THD within 2.5%–3.2%,with all stacks meeting IEEE-1547.1 Category-II ride-through.The resulting taxonomy,standards-aligned reporting,and open seeds provide a replicable basis for comparable,grid-relevant benchmarking and clear guidance for real-world design and operations.展开更多
Photovoltaic(PV)systems in the field operate under complex,uncertain conditions rapid irradiance ramps,partial shading,temperature swings,surface soiling,and weak-grid disturbances including off-nominal frequency and ...Photovoltaic(PV)systems in the field operate under complex,uncertain conditions rapid irradiance ramps,partial shading,temperature swings,surface soiling,and weak-grid disturbances including off-nominal frequency and voltage distortion that degrade energy yield and power quality.We propose a drift-aware,power-quality-constrained MPPT framework that co-optimizes MPPT,PLL,and current-loop gains under stochastic frequency drift,while enforcing IEEE-519 limits(per-order Ih/IL and TDD)during optimization.Unlike energy-only or THD-only methods,the design target integrates PQ constraints into the objective and is validated across calibrated drift scenarios with explicit per-order and TDD reporting.Operating scenarios are calibrated to Cameroon’s Southern Interconnected Grid and city-specific profiles(Douala/Yaoundé),combining measured-style irradiance/temperature traces,partial-shading patterns,and stochastic frequency drift up to±0.8 Hz with synthetic contingencies.Across a 30-scenario campaign,the proposed controller achievesηMPPT=99.3%–99.6%(vs.98.6%Incremental Conductance and 97.8%Perturb-and-Observe),lowers DC-link ripple by 35%–48%,reduces oscillatory PCC power by≈41%,maintains THD≤2.5%(5%limit)and PF≥0.99,and shortens irradiance-step settling from 85–110 ms to 50–65 ms.Sensitivity to PLL bandwidth shows a broad optimum(≈60–90 Hz)with minimum THD/ripple,and ablations confirm that explicit drift weighting is pivotal to ripple and THD suppression without sacrificing yield.The approach is controller-agnostic,firmware-deployable,and generalizes to other converter-interfaced renewables;we outline a short hardware-/HIL-validation path for adoption in Sub-Saharan grids.展开更多
I.INTRODUCTION Since the 1970s, the study of stimulated emission of CdS and other Ⅱ--Ⅵ compound semiconductors has speeded up the development of the study of highly excited semiconductors. It was shown that the ex-e...I.INTRODUCTION Since the 1970s, the study of stimulated emission of CdS and other Ⅱ--Ⅵ compound semiconductors has speeded up the development of the study of highly excited semiconductors. It was shown that the ex-el scattering induces the main recombination process that yields high gain above 100 K both experimentally and theoretically. The results obtained so far concern mainly the stimulated emission, and most of the efforts are devoted to the temperature dependence of emission spectra. Only a few works are concerning the dynamics of the luminescence due to scattering.展开更多
Hydrogen generation and related energy applications heavily rely on the hydrogen evolution reaction(HER),which faces challenges of slow kinetics and high overpotential.Efficient electrocatalysts,particularly single-at...Hydrogen generation and related energy applications heavily rely on the hydrogen evolution reaction(HER),which faces challenges of slow kinetics and high overpotential.Efficient electrocatalysts,particularly single-atom catalysts (SACs) on two-dimensional (2D) materials,are essential.This study presents a few-shot machine learning (ML) assisted high-throughput screening of 2D septuple-atomic-layer Ga_(2)CoS_(4-x)supported SACs to predict HER catalytic activity.Initially,density functional theory (DFT)calculations showed that 2D Ga_(2)CoS4is inactive for HER.However,defective Ga_(2)CoS_(4-x)(x=0–0.25)monolayers exhibit excellent HER activity due to surface sulfur vacancies (SVs),with predicted overpotentials (0–60 mV) comparable to or lower than commercial Pt/C,which typically exhibits an overpotential of around 50 m V in the acidic electrolyte,when the concentration of surface SV is lower than 8.3%.SVs generate spin-polarized states near the Fermi level,making them effective HER sites.We demonstrate ML-accelerated HER overpotential predictions for all transition metal SACs on 2D Ga_(2)CoS_(4-x).Using DFT data from 18 SACs,an ML model with high prediction accuracy and reduced computation time was developed.An intrinsic descriptor linking SAC atomic properties to HER overpotential was identified.This study thus provides a framework for screening SACs on 2D materials,enhancing catalyst design.展开更多
Despite extensive research on computational geomechanics and fluid dynamics,accurately simulating convection-diffusion(CD)processes in complex fractured systems remains a significant challenge.This study develops a 3D...Despite extensive research on computational geomechanics and fluid dynamics,accurately simulating convection-diffusion(CD)processes in complex fractured systems remains a significant challenge.This study develops a 3D numerical framework for modelling CD processes in fractured geological media.The framework integrates Darcy's law and Fick's law,considering flux interactions between the matrix and fractures.The meshing strategy generates high-quality grids even in scenarios involving intersecting fractures.Then,a unified numerical scheme for solving the CD system is proposed.The novelties of this work include:(1)The proposed framework enables effective simulation of 3D fractured media,including more complex fractured vuggy media;(2)The numerical method precisely discretizes the CD terms in governing equations;(3)A Non-Orthogonal Correction(NOC)method,combined with an adaptive time integration scheme,is proposed for eliminating errors induced by skewed grids;and(4)The effects of fracture patterns and heterogeneity on flow are thoroughly analysed.The proposed method is validated through benchmark tests,demonstrating the superiority of the NOC method compared to classical methods.Further analysis reveals the evolution characteristics of pressure and concentration,offering insights into the effects of fracture patterns and heterogeneity on flow and diffusion processes.展开更多
Dissolution kinetics of CaO·2Al_(2)O_(3)(CA_(2))particles in a synthetic CaO-Al_(2)O_(3)-SiO_(2)steelmaking slag system have been investigated using the high-temperature confocal laser scanning microscope.Effects...Dissolution kinetics of CaO·2Al_(2)O_(3)(CA_(2))particles in a synthetic CaO-Al_(2)O_(3)-SiO_(2)steelmaking slag system have been investigated using the high-temperature confocal laser scanning microscope.Effects of temperature(i.e.,1500,1550,and 1600℃)and slag composition on the dissolution time of CA_(2)particles are investigated,along with the time dependency of the projection area of the particle during the dissolution process.It is found that the dissolution rate was enhanced by either an increase in temperature or a decrease in slag viscosity.Moreover,a higher ratio of CaO/Al_(2)O_(3)(C/A)leads to an increased dissolution rate of CA_(2)particle at 1600℃.Thermodynamic calculations suggested the dissolution product,i.e.,melilite,formed on the surface of the CA_(2)particle during dissolution in slag with a C/A ratio of 3.8 at 1550℃.Scanning electron microscopy equipped with energy dispersive X-ray spectrometry analysis of as-quenched samples confirmed the dissolution path of CA_(2)particles in slags with C/A ratios of 1.8 and 3.8 as well as the melilite formed on the surface of CA_(2)particle.The formation of this layer during the dissolution process was identified as a hindrance,impeding the dissolution of CA_(2)particle.A valuable reference for designing or/and choosing the composition of top slag for clean steel production is provided,especially using calcium treatment during the secondary refining process.展开更多
目的获得噪声下声调识别测试（t o n e identification in noise test,TINT）材料的听力正常人识别成绩-强度（performance-intensity,PI）函数。方法利用已确立的TINT测试材料对16名年龄在21~28岁、以普通话作为日常交流语言的听力正...目的获得噪声下声调识别测试（t o n e identification in noise test,TINT）材料的听力正常人识别成绩-强度（performance-intensity,PI）函数。方法利用已确立的TINT测试材料对16名年龄在21~28岁、以普通话作为日常交流语言的听力正常人进行声调识别测试,使用SPSS17.0统计软件对结果进行分析。结果听力正常成人PI斜率分别为8.6%/d B（男声）、7.3%/d B（女声）（P=0.11）;听力正常成人PI函数信噪比50阈值分别为男声（-12.9±0.8）d B、女声（-13.6±1）d B（t=2.7,P=0.016）;声调类型和播音者性别对PI曲线阈值的影响即存在交互作用（F=11.7,P〈0.001）、亦存在独立作用（声调类型：F=83.7,P〈0.001;播音员性别：F=31.0,P〈0.05）,其中听力正常人一声和四声识别阈值明显低于二声和三声识别阈值。结论本研究初步建立基于TINT测试材料的听力正常人噪声下声调识别PI函数,以期为临床工作和科学研究提供一个可选择的测量工具。展开更多
文摘沙尘是中国北方典型的灾害天气。构建长时间尺度东亚地区高分辨率沙尘气溶胶质量浓度再分析数据集,是深化理解中国沙尘天气发生机理和提升多尺度预报水平的数据基础。受到风蚀起沙过程参数化方案、长距离输送误差等限制,当前沙尘模拟结果存在较大不确定性。鉴于此,本研究在前期开发的沙尘同化系统基础上,集成地面PM_(10)质量浓度、卫星气溶胶光学厚度(aerosol optical depth,AOD)观测非沙尘组分偏差校正技术,以及适用于沙尘气溶胶强度、位置误差协同校正的有效时刻偏移卡尔曼滤波同化算法(valid time shift ensemble Kalman filter,VTS-EnKF),建立了10 a(2014—2023年)东亚地区春季(3—5月)逐3 h的沙尘气溶胶三维质量浓度再分析数据集,分辨率为0.25°×0.25°。在此基础上,分析了所建立的再分析数据集相较于MERRA-2(modern-era retrospective analysis for research and applications version 2)沙尘再分析产品的优势,同时讨论了过去10 a东亚地区春季沙尘天气的月、年际变化趋势。
文摘Heavy metal contamination is a global issue caused by anthropogenic activities leading to severe negative effects on the environment and human health.To address this problem,bioremediation strategies utilizing plants such as Typha latifolia and their symbiotic fungi have been adopted to remediate contaminated areas and mitigate the harmful effects of these pollutants.In this study,the endophytic fungus Neosartorya fischeri was isolated from the roots of T.latifolia plants growing in heavy metal-contaminated sites.N.fischeri colonized the epidermis and root cortex and showed high tolerance to toxic concentrations of silver(Ag)(1 mg/kg),copper(Cu)(60 mg/kg)and cadmium(Cd)(8 mg/kg).N.fischeri removed 8.7%±0.5%Cd from the medium,biosorbed 15.24±0.2 mg/kg into its biomass,and enhanced the tolerance and bioaccumulation of Cd(184.18±1.14 mg/kg)in plant roots.Moreover,N.fischeri produces siderophores,volatile compounds and solubilizes phosphates,which improve plant fitness.This was evidenced by a 28%increase in photosynthetic pigments in T.latifolia plants colonized with N.fischeri.Additionally,N.fischeri inhibits the growth of important phytopathogens from the Fusarium genus.These findings highlight the important role of N.fischeri in enhancing the fitness and resilience of T.latifolia in hostile environments,demonstrating the potential of N.fischeri-T.latifolia association for the bioremediation of contaminated sites.
文摘The cultivation of Soledad pepper(Capsicum annuum L.)is essential in Oaxaca and Veracruz,but it faces issues with pests and diseases,which affect yield and cause economic losses.To mitigate these impacts,farmers have started using biostimulants such as chitosan and plant growth promoting bacteria instead of agrochemicals due to their environmental and health benefits.This study evaluated the effect of Bacillus subtilis and chitosan,both individually and combined,on the growth,yield,and fruit quality of Soledad pepper under greenhouse conditions.Four treatments were applied at different stages of the crop cycle:Q(Chitosan),BS(Bacillus subtilis),Q+BS(Chitosan+Bacillus subtilis),and T(Control).The results showed that the combination of chitosan and Bacillus subtilis significantly improved plant growth,especially in height and stem diameter.The chitosan treatment produced the highest number of fruits and plant weight,while the combination of chitosan and Bacillus subtilis enhanced fruit quality,increasing characteristics such as size,weight,pericarp thickness,and physicochemical parameters,notably in brix degrees,citric acid percentage,and pH,outperforming the individual treatments and the control.
文摘Utility-scale PV plants increasingly operate under partial shading,soiling,temperature swings,and rapid irradiance ramps that depress yield and challenge stability on weak grids.This critical review addresses those conditions by(i)unifying a stressor-to-method taxonomy that links field stressors to global intelligent MPPT(metaheuristics and learning-based trackers)and to advanced inverter controls(adaptive/MPC and grid-forming),(ii)standardizing metrics and reporting aligned with IEC 61724-1 and IEEE 1547/1547.1 to enable fair,reproducible comparisons,and(iii)framing MPPT and grid support as a co-design problem with a DT→HIL→Field validation pathway and seedable scenarios.We identify persistent gaps—fragmented partial-shading benchmarks,limited low-SCR testing,and scarce field-grade validation—and compile a quantitative synthesis:global soiling typically reduces annual production by≈3%–5%,and hybrid/learning MPPT frequently report≈99%tracking efficiency under PSC in simulation/HIL studies.To demonstrate practical relevance,we validate the framework on a seeded scenario library:DRL trackers achieve medianηMPPT≈0.996 with t95≈0.19 s and Hybrid trackers≈0.992/0.26 s,outperforming Metaheuristics(≈0.984/0.42 s);at SCR=2.5,grid-forming control raises VRI from~0.78(tuned GFL)to~0.95 while keeping THD within 2.5%–3.2%,with all stacks meeting IEEE-1547.1 Category-II ride-through.The resulting taxonomy,standards-aligned reporting,and open seeds provide a replicable basis for comparable,grid-relevant benchmarking and clear guidance for real-world design and operations.
基金Deanship of Research and Graduate Studies at King Khalid University for funding this work through the Large Research Project(Grant No.RGP2/587/46).
文摘Photovoltaic(PV)systems in the field operate under complex,uncertain conditions rapid irradiance ramps,partial shading,temperature swings,surface soiling,and weak-grid disturbances including off-nominal frequency and voltage distortion that degrade energy yield and power quality.We propose a drift-aware,power-quality-constrained MPPT framework that co-optimizes MPPT,PLL,and current-loop gains under stochastic frequency drift,while enforcing IEEE-519 limits(per-order Ih/IL and TDD)during optimization.Unlike energy-only or THD-only methods,the design target integrates PQ constraints into the objective and is validated across calibrated drift scenarios with explicit per-order and TDD reporting.Operating scenarios are calibrated to Cameroon’s Southern Interconnected Grid and city-specific profiles(Douala/Yaoundé),combining measured-style irradiance/temperature traces,partial-shading patterns,and stochastic frequency drift up to±0.8 Hz with synthetic contingencies.Across a 30-scenario campaign,the proposed controller achievesηMPPT=99.3%–99.6%(vs.98.6%Incremental Conductance and 97.8%Perturb-and-Observe),lowers DC-link ripple by 35%–48%,reduces oscillatory PCC power by≈41%,maintains THD≤2.5%(5%limit)and PF≥0.99,and shortens irradiance-step settling from 85–110 ms to 50–65 ms.Sensitivity to PLL bandwidth shows a broad optimum(≈60–90 Hz)with minimum THD/ripple,and ablations confirm that explicit drift weighting is pivotal to ripple and THD suppression without sacrificing yield.The approach is controller-agnostic,firmware-deployable,and generalizes to other converter-interfaced renewables;we outline a short hardware-/HIL-validation path for adoption in Sub-Saharan grids.
基金Project supported by the National Natural Science Foundation of China
文摘I.INTRODUCTION Since the 1970s, the study of stimulated emission of CdS and other Ⅱ--Ⅵ compound semiconductors has speeded up the development of the study of highly excited semiconductors. It was shown that the ex-el scattering induces the main recombination process that yields high gain above 100 K both experimentally and theoretically. The results obtained so far concern mainly the stimulated emission, and most of the efforts are devoted to the temperature dependence of emission spectra. Only a few works are concerning the dynamics of the luminescence due to scattering.
文摘Hydrogen generation and related energy applications heavily rely on the hydrogen evolution reaction(HER),which faces challenges of slow kinetics and high overpotential.Efficient electrocatalysts,particularly single-atom catalysts (SACs) on two-dimensional (2D) materials,are essential.This study presents a few-shot machine learning (ML) assisted high-throughput screening of 2D septuple-atomic-layer Ga_(2)CoS_(4-x)supported SACs to predict HER catalytic activity.Initially,density functional theory (DFT)calculations showed that 2D Ga_(2)CoS4is inactive for HER.However,defective Ga_(2)CoS_(4-x)(x=0–0.25)monolayers exhibit excellent HER activity due to surface sulfur vacancies (SVs),with predicted overpotentials (0–60 mV) comparable to or lower than commercial Pt/C,which typically exhibits an overpotential of around 50 m V in the acidic electrolyte,when the concentration of surface SV is lower than 8.3%.SVs generate spin-polarized states near the Fermi level,making them effective HER sites.We demonstrate ML-accelerated HER overpotential predictions for all transition metal SACs on 2D Ga_(2)CoS_(4-x).Using DFT data from 18 SACs,an ML model with high prediction accuracy and reduced computation time was developed.An intrinsic descriptor linking SAC atomic properties to HER overpotential was identified.This study thus provides a framework for screening SACs on 2D materials,enhancing catalyst design.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51991392 and 42293355).
文摘Despite extensive research on computational geomechanics and fluid dynamics,accurately simulating convection-diffusion(CD)processes in complex fractured systems remains a significant challenge.This study develops a 3D numerical framework for modelling CD processes in fractured geological media.The framework integrates Darcy's law and Fick's law,considering flux interactions between the matrix and fractures.The meshing strategy generates high-quality grids even in scenarios involving intersecting fractures.Then,a unified numerical scheme for solving the CD system is proposed.The novelties of this work include:(1)The proposed framework enables effective simulation of 3D fractured media,including more complex fractured vuggy media;(2)The numerical method precisely discretizes the CD terms in governing equations;(3)A Non-Orthogonal Correction(NOC)method,combined with an adaptive time integration scheme,is proposed for eliminating errors induced by skewed grids;and(4)The effects of fracture patterns and heterogeneity on flow are thoroughly analysed.The proposed method is validated through benchmark tests,demonstrating the superiority of the NOC method compared to classical methods.Further analysis reveals the evolution characteristics of pressure and concentration,offering insights into the effects of fracture patterns and heterogeneity on flow and diffusion processes.
基金the Natural Sciences and Engineering Research Council of Canada(NSERC)for funding this researchThis research used a high temperature confocal laser scanning microscope-VL2000DX-SVF17SP funded by Canada Foundation for Innovation John Evans Leaders Fund(CFI JELF,Project Number:32826),a PANalytical X’Pert diffraction instrument located at the Centre for crystal growth,Brockhouse Institute for Materials Research,and a scanning electron microscope-JEOL 6610 located at the Canadian Centre for Electron Microscopy at McMaster University.W.Mu would like to acknowledge Swedish Iron and Steel Research Office(Jernkonteret),STINT and SSF for supporting the time for international collaboration research regarding clean steel.
文摘Dissolution kinetics of CaO·2Al_(2)O_(3)(CA_(2))particles in a synthetic CaO-Al_(2)O_(3)-SiO_(2)steelmaking slag system have been investigated using the high-temperature confocal laser scanning microscope.Effects of temperature(i.e.,1500,1550,and 1600℃)and slag composition on the dissolution time of CA_(2)particles are investigated,along with the time dependency of the projection area of the particle during the dissolution process.It is found that the dissolution rate was enhanced by either an increase in temperature or a decrease in slag viscosity.Moreover,a higher ratio of CaO/Al_(2)O_(3)(C/A)leads to an increased dissolution rate of CA_(2)particle at 1600℃.Thermodynamic calculations suggested the dissolution product,i.e.,melilite,formed on the surface of the CA_(2)particle during dissolution in slag with a C/A ratio of 3.8 at 1550℃.Scanning electron microscopy equipped with energy dispersive X-ray spectrometry analysis of as-quenched samples confirmed the dissolution path of CA_(2)particles in slags with C/A ratios of 1.8 and 3.8 as well as the melilite formed on the surface of CA_(2)particle.The formation of this layer during the dissolution process was identified as a hindrance,impeding the dissolution of CA_(2)particle.A valuable reference for designing or/and choosing the composition of top slag for clean steel production is provided,especially using calcium treatment during the secondary refining process.
文摘目的获得噪声下声调识别测试（t o n e identification in noise test,TINT）材料的听力正常人识别成绩-强度（performance-intensity,PI）函数。方法利用已确立的TINT测试材料对16名年龄在21~28岁、以普通话作为日常交流语言的听力正常人进行声调识别测试,使用SPSS17.0统计软件对结果进行分析。结果听力正常成人PI斜率分别为8.6%/d B（男声）、7.3%/d B（女声）（P=0.11）;听力正常成人PI函数信噪比50阈值分别为男声（-12.9±0.8）d B、女声（-13.6±1）d B（t=2.7,P=0.016）;声调类型和播音者性别对PI曲线阈值的影响即存在交互作用（F=11.7,P〈0.001）、亦存在独立作用（声调类型：F=83.7,P〈0.001;播音员性别：F=31.0,P〈0.05）,其中听力正常人一声和四声识别阈值明显低于二声和三声识别阈值。结论本研究初步建立基于TINT测试材料的听力正常人噪声下声调识别PI函数,以期为临床工作和科学研究提供一个可选择的测量工具。
