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Effects of chloride on electrochemical and stress corrosion cracking behavior of 9Cr ferritic-martensitic steel

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Journal of Iron and Steel Research International 2020年第6期27卷 719-731页

作者： Zhen Zhang Zheng-fei Hu Liang He Xiao-bo Zhang xin-xian Fang bao-sen Zhang zhi-xin ba Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology Nanjing 211167JiangsuChina School of Materials Science and Engineering Nanjing Institute of TechnologyNanjing 211167JiangsuChina School of Materials Science and Engineering Tongji UniversityShanghai 201804China School of Materials Science and Engineering Georgia Institute of TechnologyAtlanta 30332-0620USA

The electrochemical and stress corrosion cracking behavior of 9Cr ferritic-martensitic steel is investigated in the chloride environment by using the traditional electrochemical method, the scanning vibrating electrode technique and the slow strain rate test (SSRT). Results of the static corrosion tests and corrosion morphology show that the prior austenite grain boundaries and martensite lath boundaries are the preferred sites for pit nucleation and growth in chloride environment. Results of SSRT coupled with insitu electrochemical test show that the transition from pitting corrosion to uniform corrosion, as well as the nucleation of stress corrosion crack, is the synergistic effects of the chloride and applied load. Stress corrosion cracking of the steel in the chloride environment can be divided into three different regions as follows: fast and uniform corrosion activ-ity, microcrack nucleation and propagation, and active crack growth regions.

关键词： 9Cr ferritic-martensitic steel Chloride In situ electrochemical test Scanning vibrating electrode technique Stress corrosion cracking

Cerium-based Sealing Treatment of Mg–Al Hydrotalcite Film on AZ91D Magnesium Alloy

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Acta Metallurgica Sinica(English Letters) 2016年第11期29卷 993-1000页

作者： Qiang-Sheng Dong zhi-xin ba Zhang-Zhong Wang Juan Kuang Zheng-Yang Cai Chen Yuan School of Materials Science and Engineering Nanjing　Institute of Technology Nanjing 211167 China Jiangsu Key Laboratory of Advanced Structural Materialsand Application Technology Nanjing 211167 China

An environment-friendly cerium-based sealing treatment was developed to improve the surface integrity and corrosion resistance of Mg–Al hydrotalcite film on AZ91D magnesium alloy. The cerium dioxide was generated through three stages namely nucleation, growth and dissolution, modifying the surface of AZ91D Mg alloy, and the hydrotalcite film became integral after being treated for 30 min. The results of polarization curves showed that the anti-corrosive performance of the hydrotalcite film was enhanced by the sealing treatment. Moreover, the immersion tests and electrochemical impedance spectrum measurements also demonstrated that the sealed hydrotalcite film provided a longer-term protection of magnesium alloy from corrosion as compared to the unsealed one.

关键词： AZ91D magnesium alloy Mg-Al hydrotalcite film Sealing treatment Ce-containing solution Corrosion resistance

Electric field assisted chemical conversion process of AZ91D magnesium alloy in HCO_3^-/CO_3^(2-) solution

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Transactions of Nonferrous Metals Society of China 2014年第12期24卷 3818-3824页

作者：巴志新章晓波王章忠方信贤董强胜王强南京工程学院材料工程学院南京211167 江苏省先进结构材料与应用技术重点实验室南京211167 江苏康尚医疗器械有限公司丹阳212300

A new method for synthesizing Mg-Al hydrotalcite conversion coating on AZ91D Mg alloy was developed by the application of electric field （EF）. By using EF technique, the formation time of the coating can be significantly reduced. The SEM results indicate that a continuous and compact Mg-Al hydrotalcite coating is formed on the surface of Mg alloy after short time EF treatment. However, a long time treatment would make the coating partially exfoliate. The corrosion current density （Jcor ） of the coated sample （EF1＋1 h） is approximately two orders of magnitude lower than that of Mg alloy substrate. The test of electrochemical impedance spectroscopy （EIS） and immersion corrosion also suggest that the coating can effectively protect Mg alloy against corrosion.

关键词： magnesium alloy Mg-Al hydrotalcite conversion coating corrosion resistance electric field

Microstructure and biocorrosion behaviors of solution treated and as-extruded Mg-2.2Nd-x Sr-0.3Zr alloys

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Transactions of Nonferrous Metals Society of China 2014年第12期24卷 3797-3803页

作者：章晓波巴志新王章忠薛亚军王强南京工程学院材料工程学院南京211167 江苏省先进结构材料与应用技术重点实验室南京211167 江苏康尚医疗器械有限公司丹阳212300

Mg-2.2Nd-xSr-0.3Zr alloys （x=0, 0.4 and 0.7, mass fraction, %） were prepared by gravity casting. Solution treatment was conducted on the as-cast alloys to homogenize microstructure, and hot extrusion was subsequently conducted. Microstructure was observed using an optical microscope and a scanning electron microscope. Biocorrosion behaviors of the alloy in simulated body fluid were analyzed by mass loss, hydrogen evolution and Tafel polarization experiments. The results show that the amount of residual eutectic phase of the solution treated alloys increases with increasing Sr addition, and the grains are significantly refined after hot extrusion. The corrosion resistance of the solution treated alloys deteriorates apparently with increasing Sr addition, while the corrosion resistance of the as-extruded alloys is improved with Sr addition. Nevertheless, the biocorrosion behavior of the as-extruded alloys obtained by Tafel polarization shows different trends from those obtained by the other two methods.

关键词： magnesium alloy strontium microstructure biocorrosion behaviors

Multi-Step Clustering of Smart Meters Time Series:Application to Demand Flexibility Characterization of SME Customers

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 869-907页

作者： Santiago bañales Raquel Dormido Natividad Duro Department of Computer Sciences and Automatic Control Universidad Nacional de Educación a Distancia(UNED)Madrid28040Spain Iberdrola Innovation Middle East Doha210177Qatar

Customer segmentation according to load-shape profiles using smart meter data is an increasingly important application to vital the planning and operation of energy systems and to enable citizens’participation in the energy *** study proposes an innovative multi-step clustering procedure to segment customers based on load-shape patterns at the daily and intra-daily time *** meter data is split between daily and hourly normalized time series to assess monthly,weekly,daily,and hourly seasonality patterns *** dimensionality reduction implicit in the splitting allows a direct approach to clustering raw daily energy time series *** intraday clustering procedure sequentially identifies representative hourly day-unit profiles for each customer and the entire *** the first time,a step function approach is applied to reduce time series *** attributes embedded in surveys are employed to build external clustering validation metrics using Cramer’s V correlation factors and to identify statistically significant determinants of load-shape in energy *** addition,a time series features engineering approach is used to extract 16 relevant demand flexibility indicators that characterize customers and corresponding clusters along four different axes:available Energy(E),Temporal patterns(T),Consistency(C),and Variability(V).The methodology is implemented on a real-world electricity consumption dataset of 325 Small and Medium-sized Enterprise(SME)customers,identifying 4 daily and 6 hourly easy-to-interpret,well-defined *** application of the methodology includes selecting key parameters via grid search and a thorough comparison of clustering distances and methods to ensure the robustness of the *** research can test the scalability of the methodology to larger datasets from various customer segments(households and large commercial)and locations with different weather and socioeconomic conditio

关键词： Electric load clustering load profiling smart meters machine learning data mining demand flexibility demand response

High-gain and low-distortion Brillouin amplification based on pump multi-frequency intensity modulation

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Chinese Physics B 2019年第2期28卷 277-282页

作者： Li-Wen Sheng De-xin ba zhi-Wei Lv National Key Laboratory of Science and Technology on Tunable Laser Harbin Institute of Technology

Using a pump with a multi-line spectrum to broaden the Brillouin gain bandwidth is an effective way to achieve lowdistortion amplification with high gain. Here, we theoretically and experimentally investigate the generation of a broadband Brillouin gain spectrum based on multi-frequency intensity modulation in an optical fiber. The arbitrary bandwidth of the Brillouin gain spectrum of stimulated Brillouin scattering(SBS) can be obtained as expected. In our experiment, a broadband Brillouin gain spectrum with a bandwidth of about 200 MHz is demonstrated. We also achieve a low-distortion amplification of a weak signal, whose maximum magnification is 65 d B for a-68-dBm input power signal.

关键词： Brillouin gain spectrum bandwidth intensity modulation low distortion amplification

Novel ba_(0.5)Sr_(0.5)Fe_(0.8)Zn_(0.2)O_(3-δ) membranes for POM

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Chinese Chemical Letters 2009年第2期20卷 250-252,F0003页

作者： Hui Xia Luo Ling Hui Yu xin zhi Chen Hai Hui Wang Jtirgen Caro The Key Lab of Enhanced Heat Transfer and Energy Conservation of Chinese Ministry of Education School of Chemistry & Chemical Engineering South China University of Technology Guangztwu 510640 China Institute of Physical Chemistry and Electrochemistry Leibniz University Hannover Callinstr. 3-34 D-30179 Hannover Germany

A novel cobalt-free perovskite based on ba0.5Sr0.5Fe0.8Zn0.2O3-δ （BSFZ） were prepared by EDTA-citric acid method. The lattice constants of the BSFZ perovskite were characterized by in situ high-temperature X-ray diffraction （HTXRD）. The thermal expansion coefficient of BSFZ is 10.5×10^-6 K^-1, which is lower than that of cobalt-based perovskite materials. The BSFZ membrane was also used to construct reactors for the partial oxidation of methane （POM） to syngas. Results show that the BSFZ membrane can be operated for the POM reaction for more than 100 h without any fractures. The CO selectivity of 97% is obtained. The steady oxygen permeation flux reaches around 2.5 mL/min cm^2 during POM reaction.

关键词： Membrane Oxygen separation Mixed conductor Perovskite POM

RO-heparin Inhibits L-Selectin-mediated Neutrophils Adhesion to Vascular Endothelium Under Flow Conditions

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Chemical Research in Chinese Universities 2006年第3期22卷 302-307页

作者： CHEN zhi-hong XU Li ba Xue-qing ZENG Xian-lu Institute of Genetics and Cytology Northeast Normal University Changchun 130024 P. R. China School of Life Science Mudanjiang Medical University Mudanjiang 157011 P. R. China Biology Section College of Changchun Traditional Chinese Medicine Changchun 130017 P. R. China

Selectins are carbohydrate-binding cell adhesion molecules that play a major role in the initiation of inflammatory responses. Accumulaed evidence has suggested that heparin＇s anti-inflammatory effects are mainly mediated by blocking L-or P-selectin-initiated cell adhesion. Recently, we have reported that periodate-oxidized, borohydridereduced heparin （RO-heparln） can inhibit P-selectin-mediated acute inflammation. Here we further examined the effect of RO-heparin on the adhesion of L-selectin-mediated leukocytes to vascular endothelium under flow conditions in vivo and in vitro. The results show that RO-heparin with a low anticoagulant activity can effectively reduce leucocyte roiling on thioglycoUate-induced rat mesenterlc venules and L-selectin-metadiated neutrophil roiling on TNF-α-induced human umbilical vein endothelial cells（HUVECs） under flow conditions. Our findings suggest that the effect of RO-heparin on inflammatory responses is mainly a result of its inhibiting the interaction between P- or L-selectin and its ligands. The findings also suggest that RO-heparin may be useful in preventing inflammation diseases.

关键词： RO-heparin Neutrophils adhesion L-selectin Human umbilical vein endothelial cells (HUVECs)

Sharkskin-Inspired Magnetoactive Reconfigurable Acoustic Metamaterials

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Research 2020年第1期2020卷 799-811页

作者： Kyung Hoon Lee Kunhao Yu Hasan Al ba’ba’a An xin Zhangzhengrong Feng Qiming Wang Sonny Astani Department of Civil and Environmental Engineering University of Southern CaliforniaLos AngelesCA 90089USA

Most of the existing acoustic metamaterials rely on architected structures with fixed configurations,and thus,their properties cannot be modulated once the structures are *** active acoustic metamaterials highlight a promising opportunity to on-demand switch property states;however,they typically require tethered loads,such as mechanical compression or pneumatic *** untethered physical stimuli to actively switch property states of acoustic metamaterials remains largely ***,inspired by the sharkskin denticles,we present a class of active acoustic metamaterials whose configurations can be on-demand switched via untethered magnetic fields,thus enabling active switching of acoustic transmission,wave guiding,logic operation,and *** key mechanism relies on magnetically deformable Mie resonator pillar(MRP)arrays that can be tuned between vertical and bent states corresponding to the acoustic forbidding and conducting,*** MRPs are made of a magnetoactive elastomer and feature wavy air channels to enable an artificial Mie resonance within a designed frequency *** Mie resonance induces an acoustic bandgap,which is closed when pillars are selectively bent by a sufficiently large magnetic *** magnetoactive MRPs are further harnessed to design stimuli-controlled reconfigurable acoustic switches,logic gates,and *** of creating the first generation of untethered-stimuli-induced active acoustic metadevices,the present paradigm may find broad engineering applications,ranging from noise control and audio modulation to sonic camouflage.

关键词： typically conducting artificial