The stress corrosion cracking (SCC) behaviour of X-70 pipeline steel in near-neutral pH solutions was studied via slow strain rate testing (SSRT). The results showed that the cracking mode of X-70 pipeline steel in ne...The stress corrosion cracking (SCC) behaviour of X-70 pipeline steel in near-neutral pH solutions was studied via slow strain rate testing (SSRT). The results showed that the cracking mode of X-70 pipeline steel in near-neutral pH solutions was transgranular at different temperatures and applied potentials with the feature of quasi-cleavage. The pH value of the solution decreased with increasing the addition of CO2, which increased the susceptibility to SCC. SCC susceptibility increased as the applied potential moved towards the cathodic direction, suggesting that hydrogen induced cracking (HIC) dominated the cracking process at cathodic potentials. The slight decrease of pH values with decreasing temperature of the solution increased the susceptibility to SCC, which attributed to the change of solubility of CO2 in the solution at different temperatures. The propagating directions of SCC cracks were different at different potentials. At rather negative cathodic potentials, the cracks were almost perpendicular to the tensile axis, while at free corrosion potential and near anodic potentials, cracks were nearly at 45 degree, and in the range of moderate cathodic potentials both propagating directions could be observed.展开更多
Cobalt-based phosphate/phosphonates are a class of promising water oxidation catalysts at neutralpH.Herein,we reported a facile hydrothermal synthesis of various nanostructured cobalt phe-nylphosphonates.It is found t...Cobalt-based phosphate/phosphonates are a class of promising water oxidation catalysts at neutralpH.Herein,we reported a facile hydrothermal synthesis of various nanostructured cobalt phe-nylphosphonates.It is found that the number of hydroxyl group of structure-directing reagent iscrucial for the construction of 3D hierarchical structures including hierarchical nanosheet flow-er-like assemblies and nanothorn microsphere.These samples were characterized by scanningelectron microscopy,transmission electron microscopy,X-ray diffraction,infrared,and X-ray pho-toelectron spectroscopy techniques.They can act as highly efficient electrocatalysts for the oxygenevolution reaction at neutral pH.Among these,hierarchical cobalt phenylphosphonate nanothornflowers present excellent performance,affording a current density of 1 mA cm^-2 required a smalloverpotential of 393 mV.This work offers a new clue to develop high-performance metal phospho-nate/phosphate catalysts toward electrochemical water oxidation.展开更多
The cracking behaviour of X-70 pipeline steel in near-neutral pH solutions was studied under different modes of cyclic loading. The crack propagation process of X-70 pipeline steel under low frequency cyclic loading c...The cracking behaviour of X-70 pipeline steel in near-neutral pH solutions was studied under different modes of cyclic loading. The crack propagation process of X-70 pipeline steel under low frequency cyclic loading condition was controlled mainly by stress corrosion cracking （SCC） mechanism. Under mixed-mode cyclic loading, both higher tensile stress and shear stress made cracks easier to propagate. Applied cathodic potentials and high content of carbon dioxide in solutions also promoted the propagation of cracks. The propagation directions of cracks were different under different cyclic loading conditions. Under mode I （pure tensile stress） cyclic loading condition, cracks were straight and perpendicular to the tensile stress axis, while under mixed-mode 1/111 （tensile/shear stress） cyclic loading,cracks were sinuous and did not propagate in the direction perpendicular to the main tensile stress axis. Under the mixed-mode cyclic loading, cracks were much easier to propagate, suggesting that shear stress intensified the role of tensile stress. In addition, shear stress promoted the interaction between cracks, resulting in easier coalescence of cracks.展开更多
The development of neutral pH polymer electrolytes has enabled high-performance solid-state,thin,and flexible electrochemical capacitors(ECs)to provide power for future consumer electronics and Internet-of-Thing devic...The development of neutral pH polymer electrolytes has enabled high-performance solid-state,thin,and flexible electrochemical capacitors(ECs)to provide power for future consumer electronics and Internet-of-Thing devices.Notwithstanding their promising prospect,there is still some lack of understandings or disconnections from fundamental science to practical applications of these electrolytes.In this review,we provide an overview of stateof-the-art studies on ECs with neutral pH electrolytes in both liquid and solid configurations.Starting from the fundamental studies on the voltage window and ion conduction of salt species in liquid solution to polymer electrolytes,key considerations in developing neutral pH polymer electrolytes are discussed.The performance of the polymer electrolytes along with their enabled solid symmetric and asymmetric EC devices,as well as some enhanced functionalities are presented.The future directions for research on neutral pH polymer electrolytes are proposed,expected to provide reference for further enriching the fundamental knowledge and improving the device performances.展开更多
Development of earth-abundant electrocatalysts, particularly for high-efficiency hydrogen evolution reaction （HER） under benign conditions, is highly desired, but still remains a serious challenge. Herein, we report...Development of earth-abundant electrocatalysts, particularly for high-efficiency hydrogen evolution reaction （HER） under benign conditions, is highly desired, but still remains a serious challenge. Herein, we report a high-performance amorphous CoMoS4 nanosheet array on carbon cloth （CoMoS4 NS/CC）, prepared by hydrothermal treatment of a Co（OH）F nanosheet array on a carbon cloth （Co（OH）F NS/CC） in （NH4）2MoS4 solution. As a three-dimensional HER electrode, CoMoS4 NS/CC exhibits remarkable activity in 1.0 M phosphate buffer saline （pH 7）, only requiring an overpotential of 183 mV to drive a geometrical current density of 10 mA·cm-2. This overpotential is 140 mV lower than that for Co（OH）F NS/CC. Notably, this electrode also shows outstanding electrochemical durability and nearly 100% Faradaic efficiency. Density functional theory calculations suggest that CoMoS4 has a more favorable hydrogen adsorption free energy than Co（OH）F.展开更多
Constant load tests in NS4 solution purged with N2-5%CO2 gas mixture were conducted on American Petroleum Institute （API） X80 pipeline steel applied in the 2nd West-East （;as Pipeline project with and without prelo...Constant load tests in NS4 solution purged with N2-5%CO2 gas mixture were conducted on American Petroleum Institute （API） X80 pipeline steel applied in the 2nd West-East （;as Pipeline project with and without preload. The results show that cracks could initiate and propagate in X80 pipeline steel in near-neutral pH environment under a constant load condition. The life of crack initiation and propagation increased with decreasing applied stress. Preload did not change its corrosion behavior obviously. However, preload reduced the time for crack initiation.展开更多
Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinea...Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinear processes using Hammerstein model that consists of a static nonlinear polynomial function followed in series by a linear impulse response dynamic element. A new nonlinear Hammerstein MAC algorithm (named NLH-MAC) is presented in detail. The simulation control results of a pH neutralization process show that NLH-MAC gives better control performance than linear MAC and the commonly used industrial nonlinear propotional plus integral plus derivative (PID) controller. Further simulation experiment demonstrates that NLH-MAC not only gives good control response, but also possesses good stability and robustness even with large modeling errors.展开更多
目的研究X80管线钢在近中性p H溶液中的腐蚀与应力腐蚀裂纹萌生行为。方法采用电化学实验和浸泡实验研究X80管线钢在近中性p H溶液中的腐蚀行为,采用慢应变速率拉伸实验研究X80管线钢在近中性p H溶液中,在自腐蚀电位和外加电位下的应力...目的研究X80管线钢在近中性p H溶液中的腐蚀与应力腐蚀裂纹萌生行为。方法采用电化学实验和浸泡实验研究X80管线钢在近中性p H溶液中的腐蚀行为,采用慢应变速率拉伸实验研究X80管线钢在近中性p H溶液中,在自腐蚀电位和外加电位下的应力腐蚀裂纹萌生行为。结果 X80管线钢在近中性p H溶液中的极化曲线只有活化区,没有钝化区,其自腐蚀电位约为-750 m V,浸泡195天后,试样表面没有氧化膜出现,但是观察到点蚀坑。在自腐蚀电位下,X80管线钢试验表面有大量的应力腐蚀裂纹;在-500 m V阳极外加电位下,X80管线钢试验表面几乎没有观察到应力腐蚀裂纹;在-850 m V阴极外加电位下,X80管线钢试验表面的应力腐蚀裂纹很少,但是随着外加阴极电位负移到-1300 m V时,X80管线钢试验表面的应力腐蚀裂纹增多。结论 X80管线钢在近中性p H溶液中发生均匀腐蚀,但是夹杂物剥落能在X80管线钢表面形成点蚀坑。在近中性p H溶液中,在自腐蚀电位下,X80管线钢应力腐蚀裂纹萌生敏感性最强;外加阴极电位抑制应力腐蚀裂纹萌生,但是随着外加阴极电位的负移,应力腐蚀裂纹萌生敏感性增强;外加阳极电位下,由于均匀腐蚀的作用,应力腐蚀裂纹萌生敏感性较弱。展开更多
基金This work was supported by the Special Funds for the Major State Basic Research Projects G19990650 in China,also supported by the Science and Technology Commission of Shanghai Municipality via projects 025258036 and 02ZE14031.
文摘The stress corrosion cracking (SCC) behaviour of X-70 pipeline steel in near-neutral pH solutions was studied via slow strain rate testing (SSRT). The results showed that the cracking mode of X-70 pipeline steel in near-neutral pH solutions was transgranular at different temperatures and applied potentials with the feature of quasi-cleavage. The pH value of the solution decreased with increasing the addition of CO2, which increased the susceptibility to SCC. SCC susceptibility increased as the applied potential moved towards the cathodic direction, suggesting that hydrogen induced cracking (HIC) dominated the cracking process at cathodic potentials. The slight decrease of pH values with decreasing temperature of the solution increased the susceptibility to SCC, which attributed to the change of solubility of CO2 in the solution at different temperatures. The propagating directions of SCC cracks were different at different potentials. At rather negative cathodic potentials, the cracks were almost perpendicular to the tensile axis, while at free corrosion potential and near anodic potentials, cracks were nearly at 45 degree, and in the range of moderate cathodic potentials both propagating directions could be observed.
文摘Cobalt-based phosphate/phosphonates are a class of promising water oxidation catalysts at neutralpH.Herein,we reported a facile hydrothermal synthesis of various nanostructured cobalt phe-nylphosphonates.It is found that the number of hydroxyl group of structure-directing reagent iscrucial for the construction of 3D hierarchical structures including hierarchical nanosheet flow-er-like assemblies and nanothorn microsphere.These samples were characterized by scanningelectron microscopy,transmission electron microscopy,X-ray diffraction,infrared,and X-ray pho-toelectron spectroscopy techniques.They can act as highly efficient electrocatalysts for the oxygenevolution reaction at neutral pH.Among these,hierarchical cobalt phenylphosphonate nanothornflowers present excellent performance,affording a current density of 1 mA cm^-2 required a smalloverpotential of 393 mV.This work offers a new clue to develop high-performance metal phospho-nate/phosphate catalysts toward electrochemical water oxidation.
基金This work was supported by the Special Funds for the Major State Basic Research Projects in China(No.G19990650)also supported by the Science and Technology Comm is—sion of Shanghai Municipality(Projects Nos.025258036 and 02ZE14031
文摘The cracking behaviour of X-70 pipeline steel in near-neutral pH solutions was studied under different modes of cyclic loading. The crack propagation process of X-70 pipeline steel under low frequency cyclic loading condition was controlled mainly by stress corrosion cracking （SCC） mechanism. Under mixed-mode cyclic loading, both higher tensile stress and shear stress made cracks easier to propagate. Applied cathodic potentials and high content of carbon dioxide in solutions also promoted the propagation of cracks. The propagation directions of cracks were different under different cyclic loading conditions. Under mode I （pure tensile stress） cyclic loading condition, cracks were straight and perpendicular to the tensile stress axis, while under mixed-mode 1/111 （tensile/shear stress） cyclic loading,cracks were sinuous and did not propagate in the direction perpendicular to the main tensile stress axis. Under the mixed-mode cyclic loading, cracks were much easier to propagate, suggesting that shear stress intensified the role of tensile stress. In addition, shear stress promoted the interaction between cracks, resulting in easier coalescence of cracks.
文摘The development of neutral pH polymer electrolytes has enabled high-performance solid-state,thin,and flexible electrochemical capacitors(ECs)to provide power for future consumer electronics and Internet-of-Thing devices.Notwithstanding their promising prospect,there is still some lack of understandings or disconnections from fundamental science to practical applications of these electrolytes.In this review,we provide an overview of stateof-the-art studies on ECs with neutral pH electrolytes in both liquid and solid configurations.Starting from the fundamental studies on the voltage window and ion conduction of salt species in liquid solution to polymer electrolytes,key considerations in developing neutral pH polymer electrolytes are discussed.The performance of the polymer electrolytes along with their enabled solid symmetric and asymmetric EC devices,as well as some enhanced functionalities are presented.The future directions for research on neutral pH polymer electrolytes are proposed,expected to provide reference for further enriching the fundamental knowledge and improving the device performances.
基金This work was supported by the National Key Sdentific Instrument and Equipment Development Project of China （No. 21627809）, the National Natural Science Foundation of China （Nos. 21375047, 21377046, 21405059, 21575137, 21575050, and 21601064）, Natural Science Foundation of Shandong Province （Nos. ZR2016JL013 and ZR2016BQ10）, Graduate Innovation Foundation of University of Jinan （No. YCXB15004）, and the Special Foundation for Taishan Scholar Professorship of Shandong Province （No. ts20130937）.
文摘Development of earth-abundant electrocatalysts, particularly for high-efficiency hydrogen evolution reaction （HER） under benign conditions, is highly desired, but still remains a serious challenge. Herein, we report a high-performance amorphous CoMoS4 nanosheet array on carbon cloth （CoMoS4 NS/CC）, prepared by hydrothermal treatment of a Co（OH）F nanosheet array on a carbon cloth （Co（OH）F NS/CC） in （NH4）2MoS4 solution. As a three-dimensional HER electrode, CoMoS4 NS/CC exhibits remarkable activity in 1.0 M phosphate buffer saline （pH 7）, only requiring an overpotential of 183 mV to drive a geometrical current density of 10 mA·cm-2. This overpotential is 140 mV lower than that for Co（OH）F NS/CC. Notably, this electrode also shows outstanding electrochemical durability and nearly 100% Faradaic efficiency. Density functional theory calculations suggest that CoMoS4 has a more favorable hydrogen adsorption free energy than Co（OH）F.
基金supported by the National Natural Science Foundation of China (Grant No. 51025104)
文摘Constant load tests in NS4 solution purged with N2-5%CO2 gas mixture were conducted on American Petroleum Institute （API） X80 pipeline steel applied in the 2nd West-East （;as Pipeline project with and without preload. The results show that cracks could initiate and propagate in X80 pipeline steel in near-neutral pH environment under a constant load condition. The life of crack initiation and propagation increased with decreasing applied stress. Preload did not change its corrosion behavior obviously. However, preload reduced the time for crack initiation.
文摘Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinear processes using Hammerstein model that consists of a static nonlinear polynomial function followed in series by a linear impulse response dynamic element. A new nonlinear Hammerstein MAC algorithm (named NLH-MAC) is presented in detail. The simulation control results of a pH neutralization process show that NLH-MAC gives better control performance than linear MAC and the commonly used industrial nonlinear propotional plus integral plus derivative (PID) controller. Further simulation experiment demonstrates that NLH-MAC not only gives good control response, but also possesses good stability and robustness even with large modeling errors.
文摘目的研究X80管线钢在近中性p H溶液中的腐蚀与应力腐蚀裂纹萌生行为。方法采用电化学实验和浸泡实验研究X80管线钢在近中性p H溶液中的腐蚀行为,采用慢应变速率拉伸实验研究X80管线钢在近中性p H溶液中,在自腐蚀电位和外加电位下的应力腐蚀裂纹萌生行为。结果 X80管线钢在近中性p H溶液中的极化曲线只有活化区,没有钝化区,其自腐蚀电位约为-750 m V,浸泡195天后,试样表面没有氧化膜出现,但是观察到点蚀坑。在自腐蚀电位下,X80管线钢试验表面有大量的应力腐蚀裂纹;在-500 m V阳极外加电位下,X80管线钢试验表面几乎没有观察到应力腐蚀裂纹;在-850 m V阴极外加电位下,X80管线钢试验表面的应力腐蚀裂纹很少,但是随着外加阴极电位负移到-1300 m V时,X80管线钢试验表面的应力腐蚀裂纹增多。结论 X80管线钢在近中性p H溶液中发生均匀腐蚀,但是夹杂物剥落能在X80管线钢表面形成点蚀坑。在近中性p H溶液中,在自腐蚀电位下,X80管线钢应力腐蚀裂纹萌生敏感性最强;外加阴极电位抑制应力腐蚀裂纹萌生,但是随着外加阴极电位的负移,应力腐蚀裂纹萌生敏感性增强;外加阳极电位下,由于均匀腐蚀的作用,应力腐蚀裂纹萌生敏感性较弱。
