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Evolution of mechanical properties,localized corrosion resistance and microstructure of a high purity Al-Zn-Mg-Cu alloy during non-isothermal aging

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Journal of Central South University 2024年第6期31卷 1790-1807页

作者： DAI Xuan-xuan li yu-zhang liU Sheng-dan YE ling-ying BAO Chong-jun School of Materials Science and Engineering Central South UniversityChangsha 410083China Key Laboratory of lightweight and High-strength Structural Materials Changsha 410083China Key Laboratory of Non-ferrous Metals Science and Engineering(Ministry of Education) Changsha 410083China Kunming Metallurgical Research Institute Co. Ltd.Kunming 650031China

The evolution of mechanical properties,localized corrosion resistance of a high purity Al-Zn-Mg-Cu alloy during non-isothermal aging(NIA)was investigated by hardness test,electrical conductivity test,tensile test,intergranular corrosion test,exfoliation corrosion test,slow strain rate tensile test and electrochemical test,and the mechanism has been discussed based on microstructure examination by optical microscopy,electron back scattered diffraction,scanning electron microscopy and scanning transmission electron *** NIA treatment includes a heating stage from 40℃to 180℃with a rate of 20℃/h and a cooling stage from 180℃to 40℃with a rate of 10℃/*** results show that the hardness and strength increase rapidly during the heating stage of NIA since the increasing temperature favors the nucleation and the growth of strengthening precipitates and promotes the transformation of Guinier-Preston(GPI)zones toη'*** the cooling stage,the sizes ofη'phase increase with a little change in the number density,leading to a further slight increase of the hardness and *** NIA proceeds,the corroded morphology in the alloy changes from a layering feature to a wavy feature,the maximum corrosion depth decreases,and the reason has been analyzed based on the microstructural and microchemical feature of precipitates at grain boundaries and subgrain boundaries.

关键词： Al-Zn-Mg-Cu alloy non-isothermal aging mechanical properties localized corrosion resistance microstructure

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A novel TOA estimation method with effective NLOS error reduction

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The Journal of China Universities of Posts and Telecommunications 2008年第1期15卷 32-37页

作者： zhang Yi-heng CUI Qi-mei li yu-xiang zhang Ping Key Laboratory of Universal Wireless Communications Beijing University of Posts and Telecommunications Ministry of Education Wireless Technology Innovation Institute (WTI) Beijing 100876 China

It is well known that non-line-of-sight （NLOS） error has been the major factor impeding the enhancement of accuracy for time of arrival （TOA） estimation and wireless positioning. This article proposes a novel method of TOA estimation effectively reducing the NLOS error by 60%, comparing with the traditional timing and synchronization method. By constructing the orthogonal training sequences, this method converts the traditional TOA estimation to the detection of the first arrival path （FAP） in the NLOS multipath environment, and then estimates the TOA by the round-trip transmission （RTT） technology. Both theoretical analysis and numerical simulations prove that the method proposed in this article achieves better performance than the traditional methods.

关键词： TOA estimation NLOS error B3G

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Partial linear Model Averaging Prediction for Longitudinal Data

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Journal of Systems Science & Complexity 2024年第2期37卷 863-885页

作者： li Na FEI yu zhang Xinyu Faculty of Science Kunming University of Science and TechnologyKunming 650500China School of Statistics and Mathematics Yunnan University of Finance and EconomicsKunming 650221China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China

Prediction plays an important role in data *** averaging method generally provides better prediction than using any of its *** though model averaging has been extensively investigated under independent errors,few authors have considered model averaging for semiparametric models with correlated *** this paper,the authors offer an optimal model averaging method to improve the prediction in partially linear model for longitudinal *** model averaging weights are obtained by minimizing criterion,which is an unbiased estimator of the expected in-sample squared error loss plus a *** properties,including asymptotic optimality and consistency of averaging weights,are established under two scenarios:(i)All candidate models are misspecified;(ii)Correct models are available in the candidate *** studies and an empirical example show that the promise of the proposed procedure over other competitive methods.

关键词： Asymptotic optimality longitudinal data model averaging estimator partially linear model prediction

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U-Pb zircon geochronology of basaltic pyroclastic rocks from the basement beneath the Xisha Islands in the northwestern South China Sea and its geological significance

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Acta Oceanologica Sinica 2024年第2期43卷 83-93页

作者： yu zhang Kefu yu Shiying li Guangxi Laboratory on the Study of Coral Reefs in the South China Sea Guangxi UniversityNanning 530004China Coral Reef Research Center of China Guangxi UniversityNanning 530004China School of Marine Sciences Guangxi UniversityNanning 530004China Key Laboratory of Ocean and Marginal Sea Geology South China Sea Institute of OceanologyChinese Academy of ScienceGuangzhou 510301China

As one of the micro-blocks dispersed in the South China Sea(SCS), the basement of the Xisha Islands has rarely been drilled because of the thick overlying Cenozoic sediments, which has led to a confused understanding of the pre-Cenozoic basement of the Xisha Islands. Well CK-1, a kilometer-scale major scientific drill in the Xisha Islands in the northwestern SCS, penetrated thick reefal limestone(0–888.4 m) and the underlying basement rocks(888.4–901.4 m). In this study, we present the zircon U-Pb ages of basement basaltic pyroclastic rocks from Well CK-1 in the Xisha Islands of the northwestern SCS to investigate the basement nature of the Xisha microblock. The basement of Well CK-1 consists of basaltic pyroclastic rocks on the seamount. The zircon grains yielded apparent ages ranging from ca. 2 138.9 Ma to ca. 36 Ma. The old group of zircon grains from Well CK-1 was considered to be inherited zircons. Two Cenozoic zircons gave a weighted mean 206Pb/238U age of(36.3 ± 1.1) Ma,Mean Squared Weighted Deviations(MSWD) = 1.2, which may represent the maximum age of the volcano eruption. The Yanshanian inherited zircons(116.9–105.7 Ma and 146.1–130.2 Ma) from Well CK-1 are consistent with the zircons from Well XK-1, indicating that the basement of Chenhang Island may be similar to that of Well XK-1. We propose that the Xisha micro-block may have developed on a uniform Late Jurassic metamorphic crystalline basement, intruded by Cretaceous granitic magma.

关键词： South China Sea Xisha Islands basaltic pyroclastic rocks zircon

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Preparation of Magnetic TS-1 and Its Catalytic Activity

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Chemical Research in Chinese Universities 2015年第3期31卷 430-433页

作者： li yu XUE Zehui zhang Qi SUN Cuitao li Junping liU Laishuan School of Chemical Engineering and Environment North University of China Taiyuan 030051 P.R.China

Magnetic TS-1 was synthesized thesis and solvent vaporation method. The with nanosized nickelferrite particles prepared samples were characterized as nuclei via the hydrothermal syn- with N2 adsorption-desorption iso- therms, FTIR spectrometry, Raman spectrometry, X-ray diffraction, Ultraviolet-visible spectroscopy and Vibrating sample magnetometry. The results show that the composite obtained was composed of TS-1 with MFI structure and NiFe204 with spinel structure, its specific surface area was about 316 m2/g, pore volume was 0.12 cm3/g and pore size distribution was in the range of 0.5-0.7 nm. The catalytic activity of the composite was also investigated by its catalyzing the decomposition of rhodamine B oxidized by H2O2 in aqueous solution. In this case Rhodamine B pollutant could be completely degraded within 150 min. Magnetic TS-1 exhibited high photocatalytic efficiency and super paramagnetic nature for cleaning polluted water with the help of magnetic separation.

关键词： Magnetic catalyst Titanium silicalite-1 Catalytic decomposition

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Coupled simulation of fluid-particle interaction for large complex granules:A resolved CFD-DEM method for modelling the airflow in a vertical fixed bed of irregular sinter particles

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Particuology 2024年第7期90卷 292-306页

作者： Chengzhi li yu zhang Jiahe Shen Wei zhang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081China Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081China School of Transportation and Logistics Engineering Wuhan University of TechnologyWuhan 430063China Centre for Bulk Solids and Particulate Technologies The University of NewcastleCallaghan NSW 2308Australia

A resolved CFD-DEM method is proposed to simulate the fluid-particle interaction for large complex *** airflow in a vertical sinter fixed bed is numerically studied using this *** multi-sphere clumped method is used to create irregular sinter particles in *** immersed boundary method and dynamic cell refinement are applied to describe the fluid flow around particles with higher resolution,by which the fluid-particle interaction can be simulated more *** simulation results presented the packing voidage distributions and the airflow fields in the sinter beds of different single and mixed particle size *** bed pressure drops were simulated and the results were compared with the corresponding experimental *** good agreement indicated that the proposed resolved CFD-DEM method is an effective tool to model the fluid-particle interaction for irregular large granules in the gas-solid multi-phase systems.

关键词： Resolved CFD-DEM method Irregular sinter particles Multi-sphere clumped method Immersed boundary method Dynamic cell refinement

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Incorporation of perigastric tumor deposits into the TNM staging system for primary gastric cancer

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World Journal of Gastrointestinal Oncology 2023年第9期15卷 1605-1615页

作者： Yang li Shuo li Lu liu li-yu zhang Di Wu Tian-yu Xie Xin-Xin Wang Medical School of Chinese People's liberation Army The First Medical CenterChinese People's Liberation Army General HospitalBeijing 100853China Department of General Surgery The First Medical CenterChinese People's Liberation Army General HospitalBeijing 100853China

BACKGROUND The current prognostic significance of perigastric tumor deposits(TDs)in gastric cancer(GC)remains *** To assess the prognostic value of perigastric TDs and put forward a new TNM staging framework involving TDs for primary *** This study retrospectively analyzed the pathological data of 6672 patients with GC who underwent gastrectomy or surgery for GC with other diseases from January 1,2012 to December 31,2017 at the Chinese PLA General *** to the presence of perigastric TDs or not,the patients were divided into TD-positive and TD-negative groups by using the method of propensity score *** differences between TD-positive and TD-negative patients were analyzed using binary logistic regression *** Kaplan-Meier method was used to plot survival *** Cox regression modeling and the log-rank test were used to analyze the *** Perigastric TDs were found to be positive in 339(5.09%)of the 6672 patients with GC,among whom 237 were men(69.91%)and 102 were women(30.09%)(2.32:1).The median age was 59 years(range,27 to 78 years).Univariate and multivariate survival analyses indicated that TD-positive GC patients had a poorer prognosis than TD-negative patients(P<0.05).The 1-,3-,and 5-year overall survival rates of GC patients with TDs were 68.3%,19.6%,and 11.2%,respectively,and these were significantly poorer than those without TDs of the same *** was significant variation in survival according to TD locations among the GC patients(P<0.05).A new TNM staging framework for GC was formulated according to TD *** TDs appear in the gastric body,the original stages T1,T2,and T3 are classified as T4a with the new framework,and the original stages T4a and T4b both are classified as *** TDs appear in the lesser curvature,the previous stages N0,N1,N2,and N3 now both are classified as *** TDs appear in the greater curvature or the distant tissue,the patient should be categorized as

关键词： Tumor deposits Gastric cancer Prognosis Stage Overall survival

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Simulation of a torrential rainstorm in Xinjiang and gravity wave analysis

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Chinese Physics B 2018年第5期27卷 573-580页

作者： Rui Yang Yi liu ling-Kun Ran yu-li zhang Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

We used a weather research and forecasting model to simulate a torrential rainstorm that occurred in Xinjiang,China during June 16–17,*** model successfully simulated the rainfall area,precipitation intensity,and changes in *** identified a clear wave signal using the two-dimensional fast Fourier transform method;the waves propagated westwards,with wavelengths of 45–20 km,periods of 50–120 min,and phase velocities mainly concentrated in the-25 m/s to-10 m/s *** results of wavelet cross-spectral analysis further confirmed that the waves were gravity waves,peaking at 11:00 UTC,June 17,*** gravity wave signal was identified along 79.17–79.93°E,81.35–81.45°E and 81.5–81.83°*** gravity waves detected along 81.5–81.83°E corresponded well with precipitation that accumulated in 1 h,indicating that gravity waves could be considered a rainstorm precursor in future precipitation forecasts.

关键词： gravity wave rainstorm spectral analysis methods weather research and forecasting model

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Several Rules for Treating Phenol Wastewater via Oxidation by O_3/UV-formed Radicals

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Chemical Research in Chinese Universities 2006年第1期22卷 25-28页

作者： liU Miao JIAO Xin-qian WU Di DIAO Wei-li zhang yu College of Environment and Resources Jilin University Changchun 130012 P. R China

The treatment of phenol wastewater with an ultraviolet source and an oxone generator by introducing salicylic acid as the capturer is described. The presence of HO during the phenol degradation has been proved. The impacts of factors such as acidity and reaction time on the HO formation are also discussed. The results demonstrate that HO ＇ generated from ozone/UV oxidation under a basic condition is the immediate cause of phenol degradation. At room temperature and a pH value of 9. 93, the degradation of phenol occurs rapidly within 0. 5 rain and the removal of phe- nol（ 100 mg/L） is above 98. 5% within 15 min; in the meantime, the pH value declines gradually with the degradation of phenol. A discussion about the formation and the transformation of the intermediate products during phenol degradation is included.

关键词： Ozone UV oxidation Radical Phenol wastewater Degradation

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Hard carbon for sodium storage:Mechanism and performance optimization

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Nano Research 2024年第7期17卷 6038-6057页

作者： Yongxin Wang Meng li yu zhang Naiqing zhang State Key Laboratory of Urban Water Resource and Environment School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001China School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Due to the shortage of lithium resource reserves and the pressure of rising prices,sodium-ion batteries have regained the attention of the public,and shown great potential for application in the fields of grid energy storage and low-speed vehicles to achieve the purpose of complementing lithium-ion batteries,so it is imperative to promote the commercial application of sodiumion *** sodium-ion battery anode materials,hard carbon is the material most likely to be used ***,there is still much work to be done before its *** review provides a comprehensive overview of the current research status from the following three ***,the microstructure and sodium storage active sites of hard carbon are ***,the mechanism of sodium storage in hard carbon is investigated,which can be broadly categorized into four model,“insertion–filling”,“adsorption–insertion”,“adsorption–filling”,and“multistage”.Finally,from the perspective of improving the electrochemical performance of hard carbon,the performance improvement strategies proposed in recent years are *** with the performance of hard carbon commercial products of some enterprises,the future development goal of hard carbon is prospected,hoping that all sectors of society can work hard for this common goal.

关键词： sodium-ion battery hard carbon mechanism performance optimization

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