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Extreme drought triggers parallel shifts in wood anatomical and physiological traits in upper treeline of the Mediterranean Andes

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Ecological Processes 2024年第1期13卷 132-143页

作者： Luiz Santini Jr. Dylan Craven Daigard Ricardo Ortega Rodriguez Manolo Trindade Quintilhan Stephanie Gibson-Carpintero Cristina Aravena Torres Fidel A.Roig Ariel A.Mu?oz Alejandro Venegas-Gonzalez Hémera Centro de Observación de la Tierra Universidad Mayor GEMA Center for Genomics Ecology and Environment Universidad Mayor Data Observatory Foundation ANID Technology Center depart-ment of Forest Sciences ESALQ-University of Sao Paulo department of Plant Biology Institute of Biology University of Campinas Instituto de Geografía Universidad Nacional Autónoma de México (UNAM) Argentine Institute of Nivology Glaciology and Environmental Sciences(IANIGLA CONICET ) Institute of Geography Pontificia Universidad Católica de Valparaíso Instituto de Ciencias Agroalimentarias Animales y Ambientales (ICA3) Universidad de O'Higgins

Background Treeline ecotones of Mediterranean ecoregions have been affected by the increasing intensity and severity of droughts. Even though the effect of droughts on forest dynamics has been widely documented, knowledge is relatively scarce of how extreme climate episodes affect the hydraulic structure and, therefore, the phys-iology of woody plants. The Mediterranean Andes have experienced an uninterrupted period of drought since 2010, including an extremely dry year in 2019 with approximately 80% rainfall deficit. Here, we investigated shifts in wood anatomical and physiological traits of Kageneckia angustifolia, an endemic treeline species, in response to this drought *** We evaluated the xylem plasticity of three K. angustifolia populations across their natural distribution(31–35° SL) based on anatomical(vessel structure and distribution) and physiological(intrinsic water-use efficiency) variables in the tree rings. We focused on the period 2000–2020 that corresponds to before the megadrought(2000–2007),(ii) megadrought(2008–2018) and(iii) hyperdrought(2019–2020). The variables were annualized and analyzed by linear mixed-effects *** Our results provide insights to the anatomical and physiological mechanisms underlying the resilience of treeline forests to persistent droughts in central Chile. We found that the extreme drought in 2019–2020 triggered shifts in vessel size and frequency that increased hydraulic safety. These significant shifts in vessel traits occurred in parallel with a decrease in pit aperture area and an increase in water-use efficiency, further increasing the resilience of K. angustifolia to extreme drought *** Our results revealed coordinated shifts in vessel size and frequency and water-use efficiency in response to the megadrought, thereby reducing vulnerability to hydraulic failure. The apparent resilience of K. angustifolia to extreme droughts suggests that this adaptation to drought stress may incre

关键词： Dendro-anatomy Kageneckia angustifolia Xylem vulnerability Drought Climate change

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Effects of surface modification on electrochemical performance of MnO_2

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中国有色金属学会会刊：英文版 2005年第4期15卷 944-948页

作者：刘立清王建明范玉凯王国光张鉴清 depart ment of Chemistry Zhejiang University

The MnO2 samples coated with Ca（OH）2 were prepared by a liquid-phase surface treatment method. The physical properties of the samples were examined by SEM, EDAX and chemical analysis, and their electrochemical performances were investigated by means of galvanostatic charge-discharge, cyclic voltammetry and electrochemical impedance spectroscopy （EIS）. The SEM results show that the samples coated with Ca（OH）2 display a porous surface structure. The electrochemical experiments indicate that the surface modification decreases the polarization of MnO2 electrodes and improves their discharge potentials and discharge capacities.

关键词： MnO2 SEM 电化学光谱学化学电源

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Electrocrystallization nucleation and growth of NiFe alloys on brass substrate

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中国有色金属学会会刊：英文版 2005年第4期15卷 897-901页

作者：张昭 depart ment of Chemistry Zhejiang University

The electrocrystalliztion nucleation and growth process of Ni-Fe alloy was studied using cyclic voltammetry and chronoamperometry. The results show that, in the case of high deposition overpotential, the nucleation/growth process of Ni-Fe binary alloy is 3-D instantaneous, and the growth rate of the previously formed nuclei increases with overpotential. However, at low overpotential, no distinguished nucleation current can be ***, the discrepancy between the experimental non-dimensional variables(I/Im)2 and those calculated from the theoretical model was elucidated in the light of the molecular orbital theorem.

关键词： NiFe合金电镀工艺黄铜伏安法沉积作用

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ZrB_2/Al_2O_3 composite powders prepared by self-propagating high-temperature synthesis

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中国有色金属学会会刊：英文版 2005年第4期15卷 851-854页

作者：于志强杨振国 depart ment of Material Science Fudan University

Self-propagating high-temperature synthesis（SHS） method was used to synthesize ZrB2/Al2O3 composite powders from B2O3-ZrO2-Al system. X-ray diffractometry（XRD） and scanning electron microscopy（SEM） analyses show the presence of ZrB2 and Al2O3 as the primary phases in the composite powders, while the presence of a very small amount of ZrO2 is thought to be unreacted zirconium oxide. Transmission electron microscopy（TEM） and high resolution electron microscopy（HREM） observations of microstructure of the composite powders indicate that the interfaces of ZrB2/Al2O3 bond well without any interfacial reaction products. It is proposed that the good interfacial bonding of composite powders results from the ZrB2 particles crystallizing and growing on the Al2O3 particles surface with surface defects acting as nucleation centers.

关键词： ZrB2/Al2O3 复合材料高温条件合成方法微结构

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Synthesis and high-temperature performance of Ti substituted α-Ni(OH)_2

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中国有色金属学会会刊：英文版 2005年第4期15卷 823-827页

作者：刘宏兵向兰金涌 depart ment of Chemical Engineering Tsinghua University

Ti substituted α-Ni（OH）2（c=2.121nm, a =0.307nm） with perfect high-temperature performance was prepared by the co-precipitation method. The effects of Ti addition on the structure and the electrochemical properties were investigated. The results indicate that the substitution of Ti for Ni leads to the conversion of β-Ni（OH）2 to α-Ni（OH）2 and the increase of the inter layer distance along c-axis from 0.464nm to 0.707nm. Infrared study reveals that more anions（SO2-4 and CO2-3 ions） and H2O exist in the Ti substituted α-Ni（OH）2. The discharge capacity of the Ti substituted α-Ni（OH）2 is 210mA·h/g at 20℃ and reaches up to 270mA·h/g at 80℃ owing to the inhibition of the oxygen evolution at high temperature.

关键词： α-Ni(OH)2 钛合成工艺高温条件蓄电池

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Efficacy of recombinant human epidermal growth factor plus sodium hyaluronate eye drops in diabetic dry eye post-cataract surgery

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World Journal of Diabetes 2024年第6期15卷 1234-1241页

作者： Jun-Ling Li Jin Zhao Zhen-Feng Guo Chang Xiao Xuan Liu department of ophthalmology Tianjin Beichen HospitalThe Affiliated Hospital of Nankai UniversityTianjin 300400China department of ophthalmology Xianyang First People’s HospitalXianyang 712000Shaanxi ProvinceChina

BACKGROUND Dry eye syndrome(DES)after diabetic cataract surgery can seriously affect the patient’s quality of ***,effective alleviation of symptoms in patients with this disease has important clinical *** To explore the clinical effect of recombinant human epidermal growth factor(rhEGF)plus sodium hyaluronate(SH)eye drops on DES after cataract surgery in patients with *** We retrospectively evaluated 82 patients with diabetes who experienced DES after cataract surgery at Tianjin Beichen Hospital,Affiliated Hospital of Nankai University between April 2021 and April *** were classified into an observation group(42 cases,rhEGF+SH eye drops)and a control group(40 cases,SH eye drops alone),depending on the different treatment *** therapeutic efficacy,dry eye symptom score,tear film breakup time(TFBUT),basic tear secretion score[assessed using Schirmer I test(SIt)],corneal fluorescein staining(FL)score,tear inflammatory markers,adverse reactions during treat-ment,and treatment satisfaction were compared between the two *** Therapeutic efficacy was higher in the observation group compared with the control *** groups showed improved TFBUT and dry eye,as well as improved SIt and FL scores after treatment,with a more pronounced improvement in the observation *** no marked differences in adverse reactions were observed between the two groups,treatment satisfaction was higher in the observation *** rhEGF+SH eye drops rendered clinical benefits to patients by effectively ameliorating dry eye and visual impairment with favorable efficacy,fewer adverse reactions,and high safety ***,this treatment should be promoted in clinical practice.

关键词： Recombinant human epidermal growth factor Sodium hyaluronate eye drops Diabetic patients Dry eye syndrome after cataract surgery Therapeutic efficacy

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Identification and analysis based on genetic algorithm for proton exchange membrane fuel cell stack

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Journal of Central South University of Technology 2006年第4期13卷 428-431页

作者：李曦曹广益朱新坚卫东 depart ment of Control Science and Engineering Huazhong University of Science and Technolgy depart ment of Automation Shanghai Jiaotong University

The temperature of proton exchange membrane fuel cell stack and the stoichiometric oxygen in cathode have relationship with the performance and life span of fuel cells closely. The thermal coefficients were taken as important factors affecting the temperature distribution of fuel cells and components. According to the experimental analysis, when the stoichiometric oxygen in cathode is greater than or equal to 1.8, the stack voltage loss is the least. A novel genetic algorithm was developed to identify and optimize the variables in dynamic thermal model of proton exchange membrane fuel cell stack, making the outputs of temperature model approximate to the actual temperature, and ensuring that the maximal error is less than 1 ℃. At the same time, the optimum region of stoichiometric oxygen is obtained, which is in the range of 1.8-2.2 and accords with the experimental analysis results. The simulation and experimental results show the effectiveness of the proposed algorithm.

关键词： proton exchange membrane fuel cell genetic algorithm temperature thermal coefficient stoichiometric oxygen

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Insitu for mation of titania film on NiTi alloy treated with hydrogen peroxide solution at low temperature

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中国有色金属学会会刊：英文版 2005年第4期15卷 834-838页

作者：储成林周俊钟志源浦跃朴林萍华 depart ment of Materials Science and Engineering Southeast University depart ment of Physics and Materials Science City University of Hong Kong School of Public Health Southeast University

Chemically polished NiTi shape memory alloy（SMA） substrate was treated with a boiling aqueous solution containing hydrogen peroxide to form titania film in situ at low temperature. The surface characterizations of titania film on NiTi substrate were investigated by scanning electron microscopy, X-ray diffractometry and X-ray photoelectron spectroscopy. The results show that titania film is successfully fabricated in situ on NiTi SMA by this surface oxidation method. It is mainly composed of rutile and anatase, whose surface compositions and morphologies are sensitive to H2O2 content. In situ formation mechanism of titania film on NiTi substrate was discussed based on the experimental results.

关键词：二氧化钛 NiTi合金过氧化氢温度薄膜

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Temperature dependence of deformation mechanism in single crystal Ni-base superalloy

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中国有色金属学会会刊：英文版 2005年第4期15卷 759-763页

作者：张炫金涛赵乃仁王志辉孙晓峰管恒荣胡壮麒 depart ment of Superalloys Institute of Metal ResearchChinese Academy of Sciences

The tensile behavior of a new single crystal Ni-base superalloy was studied at various temperatures. Specimens were strained to fracture in the temperature range from 20℃ to 1000℃. σ0.2 is essentially unaffected by temperatures between 20℃ and 400℃. At higher temperatures it increases until it reaches a maximum at about 800℃. Beyond 800℃ a sharp decrease of strength is observed. There is a slight fluctuation in ductility between 20℃ and 800℃. The elongation to fracture increases from 10% to 36% as the temperature increases from 800℃ to 1000℃. The deformation is dominated by γ′ shearing and the high-density dislocations are observed in matrix channels at low temperatures. The dislocation microstructure is inhomogeneous due to the formation of dislocation concentrations with high-density tangling at intermediate temperatures. The networks deposited at the γ/γ′ interfaces prevent dislocations from entering the γ′ precipitates at high temperatures.

关键词：镍超耐热合金金属变形装置微结构

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Preparation and H^+ response mechanism of W/WO_3 pH electrode by sol-gel method

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中国有色金属学会会刊：英文版 2005年第4期15卷 855-862页

作者：陈东初付朝阳郑家燊王哲 School of Science Foshan University depart ment of Chemistry Huazhong University of Science and Technology

A method of sol-gel for preparing a W/WO3 pH electrode was presented. H+ response characteristics, such as response range, response sensitivity, response time were investigated. The effect of heat-treatment on response linear relation was discussed. The influences of interfered ions and solution temperatures were also taken into consideration. Many kinds of determination technology, such as TG, DSC, IR, SEM, AFM,XPS, XRD were used to characterize the film. The results show that the film appears in crack dried-mud, and the film is composed of WO3, WO3·H2O or WO3·0.33H2O; the hydrate water decreases with the increase of the heat-treatment temperature; the W+6 in the electrode film transfers to W+5 in the course of H+ response; the H+ response course is controlled by the H+ diffusion from the solution to the WO3 crystalline, which is indicated in the EIS spectra; the best heat-treatment temperature is 200℃, and at this temperature, the electrode has an H+ response sensitivity of 52mV/pH.

关键词： W/WO3 pH值电极溶胶凝胶体传感器

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