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Field corrosion characterization of soil corrosion of X70 pipeline steel in a red clay soil

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Progress in Natural Science:Materials International 2015年第3期25卷 242-250页

作者： Shengrong Wang Cuiwei Du xiaogang li Zhiyong liu Min Zhu Dawei Zhang Corrosion and Protection Center Key Lab of Minstry of Education University of Science and Technology Beijing

The corrosion behavior of X70 pipeline steel buried in red soil environment has been studied. The surface morphology and elemental distribution were determined by scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS), and X-ray diffraction(XRD).The corrosion kinetics was evaluated by weight loss measurement. The results show that in red soil, the corrosion rate of X70 steel decreases with time, and follows the exponential decay law. General corrosion with non-uniform and localized pitting occurred on the steel surface. α-Fe OOH was the dominate products during corrosion in whole buried periods, and the corrosion products exhibited well protective properties. The potentiodynamic polarization tests revealed that icorrdecreased with time, indicating the improvement of corrosion resistance. The results of Electrochemical impendence spectroscopy(EIS) are consistent with potentiodynamic polarization tests.

关键词： X70 steel Soil corrosion Corrosion kinetics Non-uniform corrosion Pitting corrosion

Corrosion Performance of Carbon Steel in CO_(2) Aqueous Environment Containing Silty Sand with Different Sizes

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Acta Metallurgica Sinica(English Letters) 2017年第11期30卷 1055-1066页

作者： Songle Lu Wei liu Shian Zhang Xiaolong Qi xiaogang li Xuemin Wang Corrosion and Protection Center Institute for Advanced Materials and Technology University of Science and Technology Beijing Beijing 100083 China Department of Materials Physics and Chemistry School of Materials Science and Engineering University of Scienceand Technology Beijing Beijing 100083 China

Corrosion performance of carbon steel in CO2 aqueous environment containing silty sand with different sizes was investigated by immersion tests and electrochemical measurements. Silty sand could form an adsorption layer on steel surface in initial period, and the sand adsorption layer was turned into a mixture film of silty sand with corrosion product in last period. The adsorption layer in 325 mesh condition （large size） had the fewest pores for H2CO3 transport, exhibiting the highest cathodic current inhibition. In spite of little corrosion product, the sand adsorption film formed in 325 mesh condition induced the lowest corrosion rate. For 1000 and 5000 mesh silty sand, the sand adsorption layer had some pores for H2CO3 transport, leading to low cathodic current inhibition and much matrix dissolution. But the adsorption layer for 5000 mesh silty sand （small size） had the largest special surface area to accelerate heterogeneous precipitation of corrosion product FeCO3. Therefore, the mixture film in 5000 mesh condition was more compact, exhibiting stronger anodic inhibition and lower corrosion rate than those in 1000 mesh condition.

关键词： Silty sand Sand adsorption layer Corrosion product film Corrosion inhibition Carbon steel

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电力交易机构数字化系统建设合规性评价研究

技术与市场 2024年第6期31卷 180-185页

作者：李晓刚承林吴敏洪元瑞国家电网有限公司华东分部上海200120 上海科驭信息科技有限公司上海201721

随着电力体制改革进程的逐步推进,外部监管环境日益严格。市场主体对电力市场技术支持系统的准确性、公正性和保密性的要求越来越高,迫切需要建立电力市场技术支持系统合规评价体系。基于电力交易机构的数字化系统建设的流程和规范,设... 详细信息

随着电力体制改革进程的逐步推进,外部监管环境日益严格。市场主体对电力市场技术支持系统的准确性、公正性和保密性的要求越来越高,迫切需要建立电力市场技术支持系统合规评价体系。基于电力交易机构的数字化系统建设的流程和规范,设计了电力市场技术支持系统建设合规性的核心评价指标体系,探索性地规划了电力交易机构数字化系统建设的合规性评价的标准作业规范流程,从而帮助电力交易机构对电力市场技术支持系统建设各环节进行更科学、准确的评估与监管。

关键词：电力市场技术支持系统合规性评价数字化

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腐蚀大数据技术背景下Mn含量对新型高强度免涂装3Ni结构钢腐蚀性能影响研究

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鞍钢技术 2024年第1期 1-14页

作者：李晓刚贾静焕李众刘超程学群北京科技大学新材料技术研究院腐蚀与防护中心北京100083 国家材料腐蚀与防护科学数据中心北京100083

针对目前3Ni钢强度不高、在滨海环境中耐蚀性不足的问题,通过提高3Ni钢中Mn含量,研究Mn元素对3Ni钢强韧性及其在高温、高湿、高盐海洋大气环境耐蚀性的影响和机制。通过力学性能测试和室内周浸试验,使用慢应变速率拉伸实验评价了Mn元素... 详细信息

针对目前3Ni钢强度不高、在滨海环境中耐蚀性不足的问题,通过提高3Ni钢中Mn含量,研究Mn元素对3Ni钢强韧性及其在高温、高湿、高盐海洋大气环境耐蚀性的影响和机制。通过力学性能测试和室内周浸试验,使用慢应变速率拉伸实验评价了Mn元素对新型免涂装3Ni结构钢力学性能及腐蚀性能的影响。利用腐蚀大数据技术,并结合机器学习方法快速评价了新型免涂装3Ni结构钢在有无应力状态下的腐蚀规律及其差异。结果表明,提高Mn含量,能在一定程度上提高3Ni钢的强度,但会使钢的低温冲击韧性变差。同时Mn元素升高不利于3Ni钢耐均匀腐蚀性能,腐蚀速率随着Mn含量的升高而增大,但Mn含量的升高并不改变新型免涂装3Ni结构钢的腐蚀形式,不同Mn含量的3Ni钢在滨海大气模拟液中均表现为不全面的均匀腐蚀特征。与此同时,腐蚀大数据技术能快速有效甄别在模拟滨海区域大气环境有无应力以及Mn元素含量对新型免涂装3Ni钢腐蚀造成的影响。无应力的新型免涂装3Ni结构钢在模拟环境的平均瞬时电流值随Mn元素含量的增高而增高,而有应力的新型免涂装3Ni结构钢平均瞬时电流值随着Mn元素含量的增高而降低。

关键词：滨海环境免涂装3Ni结构钢 Mn元素应力腐蚀腐蚀大数据技术

BARRIER LAYER IN THE NORTHEASTERN SOUTH CHINA SEA AND ITS FORMATION MECHANISM

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Chinese Science Bulletin 2006年第4期51卷 472-479页

作者： PAN Aijun WAN Xiaofang XU Jindian GUO xiaogang li li Environment and Dynamics Laboratory Third Institute of OceanographyState Oceanic Administration Xiamen 361005 China

Robust evidence for the barrier layer (BL) in the northeastern South China Sea (SCS) (16°-25°N, 112°-124°E) is presented. The occurrence rate of the BL peaks in the autumn (45.7%) and then the summer (31.1%) and the spring (23.3%), se-quently. It is estimated that the annual occurrence rate of the BL reaches about 40.0% in the central northeastern SCS (18°-22°N, 112°-120°E) and the Luzon Strait. Stratification-formed (Rain-formed) mechanism is the major factor responsible for the occurrence of the BL in the northeastern SCS in the spring (the summer and autumn), respectively. The rainfall observation from TRMM provides reliable evidence for the latter.

关键词：南海东北部阻挡层海洋层次降雨量吕宋岛海峡

A novel evasion guidance for hypersonic morphing vehicle via intelligent maneuver strategy

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Chinese Journal of Aeronautics 2024年第5期37卷 441-461页

作者： Xun li xiaogang WANG Hongyu ZHOU Yu li Department of Aerodynamics Harbin Institute of TechnologyHarbin 150001China Beijing Aerospace Technology Institute Beijing 100074China

This paper presents a novel evasion guidance law for hypersonic morphing vehicles,focusing on determining the optimized wing's unfolded angle to promote maneuverability based on an intelligent ***,the pursuit-evasion problem is modeled as a Markov decision *** the agent's action consists of maneuver overload and the unfolded angle of wings,which is different from the conventional evasion guidance designed for fixed-shape *** reward function is formulated to ensure that the miss distances satisfy the prescribed bounds while minimizing energy ***,to maximize the expected cumulative reward,a residual learning method is proposed based on proximal policy optimization,which integrates the optimal evasion for linear cases as the baseline and trains to optimize the performance for nonlinear engagement with multiple ***,offline training guarantees improvement of the constructed evasion guidance law over conventional ***,the guidance law for online implementation includes only analytical *** maps from the confrontation state to the expected angle of attack and the unfolded angle while retaining high computational *** show that the proposed evasion guidance law can utilize the change of unfolded angle to extend the maximum overload *** it surpasses conventional maneuver strategies by ensuring better evasion efficacy and higher energy efficiency.

关键词： Hypersonic vehicles Variable-sweep wings Evasion guidance Reinforcement learning Pursuit-evasion problem

Effects of laser powder bed fusion process parameters on microstructure and hydrogen embrittlement of high-entropy alloy

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Journal of Materials Science & Technology 2023年第24期155卷 211-226页

作者： Hongxu Cheng Hong Luo Zhimin Pan Xuefei Wang Qiancheng Zhao Yu Fu xiaogang li National Materials Corrosion and Protection Data Center Institute for Advanced Materials and Technology University of Science and Technology Beijing Beijing 100083 China Key Laboratory for Corrosion and Protection of The Ministry of Education (MOE) Beijing 100083 China

Hydrogen embrittlement behavior, micro-deformation, and crack propagation mechanism of CoCrFeNiMn high-entropy alloy (HEA) fabricated by laser powder bed fusion (LPBF) under different parameters were investigated by slow strain rate tensile tests (at room temperature) with/without electrochemical hydrogen pre-charging. The LPBF CoCrFeNiMn HEA shows excellent resistance to hydrogen embrittlement. Unsuitable LPBF parameters are accompanied by many microcracks and holes, resulting in a slight decrease in the hydrogen embrittlement resistance of the material. The electron backscatter diffraction (EBSD), electron channeling contrast image (ECCI) techniques, and transmission electron microscope (TEM) were carried out to research the main influencing factors of hydrogen on the deformation mechanism and crack propagation. Compared with un-charged samples, a larger number of deformation twins (DTs) appear in the deformation process of hydrogen-charged LPBF CoCrFeNiMn, attributing to the reduction of stacking fault energy (SFE) due to the ingress of hydrogen. The nano DTs and crossing twin system contribute to the extra work hardening, and a strain hardening platform is observed for all hydrogen-charged samples, resulting in the increase of strain hardening rate or the mitigation of the loss of strain hardening. Although unsuitable process parameters will trigger fabrication defects and reduce mechanical properties, the cellular structure can bring a hydrogen-induced strain hardening platform for LPBF CoCrFeNiMn to reduce the damage caused by hydrogen embrittlement.

关键词： Laser powder bed fusion High-entropy alloy Hydrogen embrittlement Deformation mechanism

Distribution and degradation kinetics of cyhalodiamide in Chinese rice field environment

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Chinese Journal of Chemical Engineering 2018年第10期26卷 2185-2191页

作者： Yiping liu Ya Zhang Shuangqing liu Yuntao Lü Ronghua lin Min li Xiaolan liao xiaogang li College of Plant Protection Hunan Agricultural University Institute for the Control of Agrochemicals Hunan Province Institute for the Control of Agrochemicals Ministry of Agriculture and Rural Affairs

Cyhalodiamide is a novel agrochemical which is effective against Lepidoptera pests,including Cnaphalocrocis medinalis,Chilo suppressalis,Pieris rapae,Plutella xylostella,Helicoverpa armigera,*** the study,a fast and accurate analytical method was developed to detect cyhalodiamide in Chinese typical rice field environment by a modified Qu ECh ERS(Quick,Easy,Cheap,Effective,Rugged,Safe)method with UPLC-MS/MS(ultra-high performance chromatography-tandem mass spectrometry).The mean recoveries of cyhalodiamide varied from 73.5% to 107.5%,with the RSDs from 1.2% to 10.7%.The limits of determination(LODs)were 0.0005 mg·kg^(-1),and the limits of quantitation(LOQs)were from 0.002 to 0.01 mg·kg^(-1)in all five *** method was used to determine cyhalodiamide residues for studies of the distribution and degradation kinetics in rice field *** field trials results showed that cyhalodiamide was easily degradable and the half-lives were4.2–13.6 d in rice straw,8.77 d in paddy soil and 5.37–8.45 d in paddy water,*** final residues of cyhalodiamide in brown rice were below 0.35 mg·kg^(-1).The used dosage of 33.75 g·hm^(-2)with pre-harvest interval(PHI)of 21 d and the maximum residue limit(MRL)of cyhalodiamide in rice at 0.1 mg·kg^(-1)were recommended,which would be safe to human health and *** developed analytical method will be useful to monitor cyhalodiamide residues and safety evaluation in rice environment.

关键词： Cyhalodiamide QuEChERS Rice Residue Degradation kinetics

Thin Film Assembly of Gold Nanoparticles for Vapor Sensing via Droplet Interfacial Reaction

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Journal of Materials Science & Technology 2013年第5期29卷 401-405页

作者： Kun Luo Tao Huang Yujia Luo Haiming Wang Chao Sang xiaogang li Key Laboratory of New Processing Technology for Nonferrous Metals & Materials Ministry of EducationCollege of Materials Science and EngineeringGuilin University of Technology China Medical University Shenbei New District

A facile approach to prepare a thin film vapor sensor is demonstrated through droplet interracial reaction on an IDA microelectrode. Scanning electron microscopy, atomic force microscopy and transmission electron microscopy analyses show that the film of the vapor sensor is composed of self-assembled gold nanocrystals in an average diameter of about 4.3 nm. The as-prepared sensor was examined by potential step method and impedance measurement, which exhibited significant △R/Ri responses and excellent cycle performance to the volatile organic compound （VOC） vapors of acetone, methanol, styrene, benzene, toluene and ethanol. The selectivity to the VOCs with benzene ring or organic solvents suggests that the sensor is probably in line with the swelling and dielectric sensing mechanisms.

关键词： Gold nanoparticle Thin film Self-assembly Droplet interfacial reaction Vapor sensor