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An early evaluation of translocation actions for endangered plant species on Mediterranean islands
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作者 Giuseppe Fenu Gianluigi Bacchetta +8 位作者 S. Christodoulou Charalambos Christini Fournaraki Gian Pietro Giusso del Galdo Panagiota Gotsiou Angelos Kyratzis Carole Piazza Magdalena Vicens Maria Silvia Pinna Bertrand de Montmollin 《植物多样性:英文版》 CAS CSCD 2019年第2期94-104,共11页
In situ conservation is widely considered a primary conservation strategy. Plant translocation, specifically, represents an important tool for reducing the extinction risk of threatened species. However, thus far, few... In situ conservation is widely considered a primary conservation strategy. Plant translocation, specifically, represents an important tool for reducing the extinction risk of threatened species. However, thus far, few documented translocations have been carried out in the Mediterranean islands. The CareMediflora project, carried out on six Mediterranean islands, tackles both short-and long-term needs for the insular endangered plants through in situ and ex situ conservation actions. The project approach is based on using ex situ activities as a tool to improve in situ conservation of threatened plant species.Fifty island plants(representing 45 taxa) were selected for translocations using common criteria.During the translocations, several approaches were used, which differed in site selection method, origin of genetic material, type of propagative material, planting method, and more. Although only preliminary data are available, some general lessons can be learned from the experience of the CareMediflora project. Among the factors restricting the implementation of translocations, limited financial resources appear to be the most important. Specific preliminary management actions, sometimes to be reiterated after translocation, increase the overall cost, but often are necessary for translocation success. Translocation using juvenile/reproductive plants produces better results over the short term,although seeds may provide good results over the long run(to be assessed in the future). Regardless,plant translocation success can only be detected over long periods;therefore, proper evaluation of plant translocations requires a long-term monitoring protocol. Care-Mediflora project represents the first attempt to combine the existing approaches in a common plant conservation strategy specifically focusing on the Mediterranean islands. 展开更多
关键词 Care-Mediflora project ex SITU CONSERVATION in SITU CONSERVATION Insular FLORA THREATENED plant populations
Illumining phase transformation dynamics of vanadium oxide cathode by multimodal techniques under operando conditions
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作者 Guobin Zhang Tengfei Xiong +6 位作者 Xuelei Pan Yunlong Zhao Mengyu Yan Haining Zhang Buke Wu Kangning Zhao Liqiang Mai 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第4期905-910,共6页
Subtle structural changes during electrochemical processes often relate to the degradation of electrode materials.Characterizing the minute-variations in complementary aspects such as crystal structure,chemical bonds,... Subtle structural changes during electrochemical processes often relate to the degradation of electrode materials.Characterizing the minute-variations in complementary aspects such as crystal structure,chemical bonds,and electron/ion conductivity will give an in-depth understanding on the reaction mechanism of electrode materials,as well as revealing pathways for optimization.Here,vanadium pentoxide (V2O5),a typical cathode material suffering from severe capacity decay during cycling,is characterized by in-situ X-ray diffraction (XRD) and in-situ Raman spectroscopy combined with electrochemical tests.The phase transitions of V2O5 within the 0-1 LiN ratio are characterized in detail.The V--O and V-V distances became more extended and shrank compared to the original ones after charge/discharge process,respectively.Combined with electrochemical tests,these variations are vital to the crystal structure cracking,which is linked with capacity fading.This work demonstrates that chemical bond changes between the transition metal and oxygen upon cycling serve as the origin of the capacity fading. 展开更多
关键词 IN-SITU X-ray DIFFRACTION (XRD) IN-SITU Raman electrochemical process phase transformation
Effect of age on visual and refractive results after LASIK: mechanical microkeratome versus femtosecond laser
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作者 Montserrat Garcia-Gonzalez Juan Gros-Otero +2 位作者 Isabel Rodriguez-Perez Alberto Rodero Miguel A.Teus 《国际眼科杂志:英文版》 SCIE CAS 2019年第3期488-495,共8页
AIM: To evaluate the effect of age on visual and refractive results after laser in situ keratomileusis(LASIK) obtained with a mechanical microkeratome or a femtosecond laser.METHODS: Retrospective, nonrandomized, coho... AIM: To evaluate the effect of age on visual and refractive results after laser in situ keratomileusis(LASIK) obtained with a mechanical microkeratome or a femtosecond laser.METHODS: Retrospective, nonrandomized, cohort study. A total of 3826 eyes were included in the study(1725 eyes treated with mechanical LASIK and 2101 eyes treated with femtosecond LASIK). The relationship between patient age and the 3-month postoperative visual and refractive results of both procedures were analyzed by linear regression analysis.RESULTS: Three months postoperatively, we found a significant correlation between age and the postoperative spherical equivalent(SE;r2=0.004, P=0.006), efficacy(r2=0.006, P=0.001), and safety indexes(r2=0.05, P=0.0001) in the mechanical LASIK group. On the other hand, we found a significant correlation between age and the postoperative SE(r2=0.02, P=0.0001) and the efficacy index(r2=0.01, P=0.0001) but not the safety index in the femtosecond laser group. Mechanical LASIK provided slightly but significantly better efficacy and predictability in patients 18 to 40 years of age and femtosecond LASIK did so in patients older than 40 years of age. The femtosecond laser provided better safety results than the mechanical microkeratome in both age groups. CONCLUSION: A tendency toward undercorrection and less predictability is found with aging after myopic LASIK regardless of whether the flap was created with a mechanical microkeratome or a femtosecond laser. However, femtosecond laser provides significantly betteroutcomes in terms of efficacy, safety and predictability compared to mechanical microkeratome for the correction of myopia in patients over 40 y. 展开更多
关键词 LASER in SITU KERATOMILEUSIS FEMTOSECOND FEMTOSECOND LASER in SITU KERATOMILEUSIS age
Surface Modification of (001) Facets Dominated TiO2 with Ozone for Adsorption and Photocatalytic Degradation of Gaseous Toluene 预览
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作者 Yue Yang Zhi-yu Wang +5 位作者 Fan Zhang Yi Fan Jing-jing Dong Song Sun Chen Gao Jun Bao 《化学物理学报》 SCIE CAS CSCD 2019年第5期611-619,共9页
This study investigated the positive effect of surface modification with ozone on the photocatalytic performance of anatase TiO2 with dominated (001) facets for toluene degradation. The performance of photocatalyst wa... This study investigated the positive effect of surface modification with ozone on the photocatalytic performance of anatase TiO2 with dominated (001) facets for toluene degradation. The performance of photocatalyst was tested on a home-made volatile organic compounds degradation system. The ozone modification, toluene adsorption and degradation mecha-nism were established by a combination of various characterization methods, in situ diuse reectance infrared fourier transform spectroscopy, and density functional theory calculation. The surface modtication with ozone can signiticantly enhance the photocatalytic degradation performance for toluene. The abundant unsaturated coordinated 5c-Ti sites on (001) facets act as the adsorption sites for ozone. The formed Ti-O bonds reacted with H2O to generate a large amount of isolated Ti5c-OH which act as the adsorption sites for toluene, and thus signi- cantly increase the adsorption capacity for toluene. The outstanding photo- catalytic performance of ozone-modified TiO2 is due to its high adsorption ability for toluene and the abundant surface hydroxyl groups, which produce very reactive OH· radicals under irradiation. Furthermore, the O2 generated via ozone dissociation could combine with the photogenerated electrons to form superoxide radicals which are also conductive to the toluene degradation. 展开更多
关键词 OZONE modification (001) FACETS TOLUENE degradation TIO2 In situ DIFFUSE reectance infrared fourier transform spectroscopy
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In Situ Coupling Strategy for Anchoring Monodisperse Co9S8 Nanoparticles on S and N Dual?Doped Graphene as a Bifunctional Electrocatalyst for Rechargeable Zn–Air Battery
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作者 Qi Shao Jiaqi Liu +4 位作者 Qiong Wu Qiang Li Heng-guo Wang Yanhui Li Qian Duan 《纳微快报:英文版》 CAS CSCD 2019年第1期64-77,共14页
An in situ coupling strategy to prepare Co9S8/S and N dual?doped graphene composite(Co9S8/NSG) has been proposed. The key point of this strategy is the function?oriented design of organic compounds. Herein, cobalt por... An in situ coupling strategy to prepare Co9S8/S and N dual?doped graphene composite(Co9S8/NSG) has been proposed. The key point of this strategy is the function?oriented design of organic compounds. Herein, cobalt porphyrin derivatives with sulfo groups are employed as not only the coupling agents to form and anchor Co9S8 on the graphene in situ, but also the heteroatom?doped agent to generate S and N dual?doped graphene. The tight coupling of multiple active sites endows the composite materials with fast electrochemical kinetics and excellent stability for both oxygen reduction reaction(ORR) and oxygen evolution reaction(OER). The obtained electrocatalyst exhibits better activity parameter(ΔE = 0.82 V) and smaller Tafel slope(47.7 mV dec-1 for ORR and 69.2 mV dec-1 for OER) than commercially available Pt/C and RuO2. Most importantly, as electrocatalyst for rechargeable Zn–air battery, Co9S8/NSG displays low charge–discharge voltage gap and outstanding long?term cycle stability over 138 h compared to Pt/C–RuO2. To further broaden its application scope, a homemade all?solid?state Zn–air battery is also prepared, which displays good charge–discharge performance and cycle performance. The function?oriented design of N4?metallomacrocycle derivatives might open new avenues to strategic construction of high?performance and long?life multifunctional electrocatalysts for wider electro?chemical energy applications. 展开更多
关键词 In situ COUPLING strategy Porphyrin derivate DOPED GRAPHENE Metal sulfide BIFUNCTIONAL ELECTROCATALYST RECHARGEABLE Zn–air battery
In situ generated pyroglutamate bridged polyoxotitaniums with strong circular dichroism signal
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作者 Guo-Liang Dong Wei-Hui Fang +1 位作者 Lei Zhang Jian Zhang 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第5期1005-1008,共4页
In this text,we use inexpensive and natural amino acid,successfully obtained the asymmetric crystallization of three PTCs,[Ti6(OiPr)14(μ2-O)(μ3-O)2(D/L-pGlu)2](D-PTC-53;L-PTC-53;H2 pGlu=pyroglutamic acid)and[Ti6(OiP... In this text,we use inexpensive and natural amino acid,successfully obtained the asymmetric crystallization of three PTCs,[Ti6(OiPr)14(μ2-O)(μ3-O)2(D/L-pGlu)2](D-PTC-53;L-PTC-53;H2 pGlu=pyroglutamic acid)and[Ti6(OiPr)14(μ2-O)(μ3-O)2(D-pGlu)2][Ti6(OiPr)14((μ2-O)(μ3-O)2(L-pGlu)2](D,L-PTC-53).Interestingly,in situ lactamide reaction starting from glutamic acid to pyroglutamic acid was observed.In addition,the chirality features of these PTCs have been thoroughly discussed.The two enantiomers crys tallize in chiral P21 space group.The optically pure pGlu ligands transform its chirality to the inorganic titanium oxo clusters.As a result,the stack of these inorganic clusters generates homochiral helical chains along the characteristic axial direction.Apart from the microscopic structural analysis,the macroscopic solid-state samples exhibit unusual strong circular dichroism(CD)signals,further verified the homochiral feature of the enantiomers. 展开更多
关键词 In SITU Gyroglutamate Polyoxotitaniums Circular DICHROISM CHIRALITY
基于SCPTU原位状态参数确定方法及液化应用试验研究
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作者 段伟 蔡国军 +2 位作者 刘松玉 邹海峰 袁俊 《岩石力学与工程学报》 EI CAS CSCD 北大核心 2019年第A01期3151-3162,共12页
状态参数可以有效地评价无黏性土的相对密实度和液化势。然而,目前状态参数的确定主要依赖于室内试验,难以反映现场土层的真实状态。地震波孔压静力触探(SCPTU)测试可以获取土层的原位锥尖阻力、侧壁摩阻力、孔隙水压力与剪切波速等原... 状态参数可以有效地评价无黏性土的相对密实度和液化势。然而,目前状态参数的确定主要依赖于室内试验,难以反映现场土层的真实状态。地震波孔压静力触探(SCPTU)测试可以获取土层的原位锥尖阻力、侧壁摩阻力、孔隙水压力与剪切波速等原位参数。本文基于SCPTU测试确定状态参数的研究成果,根据3个工程场地的SCPTU原位测试资料,首先对不同状态参数评估方法进行了比较,其次建立归一化剪切波速Vs1与原位状态参数的相关关系,绘制剪切波速与有效应力(Vs-σ′v0)平面中状态参数剖面等值线图;提出归一化小应变刚度(G0/qc)与状态参数的修正模型。最后应用于无黏性土密实度与液化势的评估中。结果表明:本文提出的2种计算方法能够有效地评估无黏性土的状态参数,并且预测的状态参数可有效地用于评价土体密实状态与液化势的可靠判别。 展开更多
关键词 土力学 地震波孔压静力触探(SCPTU) 原位 状态参数 相对密实度 液化
In Situ Electron Backscatter Diff raction Analysis for Microstructure Evolution and Deformation Models of Mg–Ce Alloy During Uniaxial Loading
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作者 Fang-Wei Jiao Li Jin +1 位作者 Jie Dong Feng-Hua Wang 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第2期263-268,共6页
Previous studies showed that signifi cant increases in elongation in Mg–Ce alloys due to the Ce addition and the solute drag eff ect by Ce addition were ascribed to the non-basal dislocation slip activating and the t... Previous studies showed that signifi cant increases in elongation in Mg–Ce alloys due to the Ce addition and the solute drag eff ect by Ce addition were ascribed to the non-basal dislocation slip activating and the texture altering. The microstructure evolution and deformation models of extruded Mg-0.5 wt%Ce alloy rods under uniaxial tension have been studied using in situ electron backscatter diff raction. The basal and non-basal slips were characterized by using slip line trace analysis. The results provide evidence for that pyramidal slip activated during deformation, besides basal slip and extension twinning, which contributes to the texture weakening and ductility increasing in Mg-0.5 wt%Ce alloy. 展开更多
关键词 Texture Non-basal SLIP TWINNING In SITU ELECTRON backscattered diff raction(EBSD) Trace ANALYSIS
A comparative study of stress influence on fracture apertures in fragmented rocks 预览
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作者 Hossein Agheshlui Mohammad H.Sedaghat Siroos Azizmohammadi 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第1期38-45,共8页
This study compares the calculated fracture apertures in a fragmented rock layer under different stress scenarios using two different approaches.Approach 1 is a simplified method using a two-dimensional(2D)mapping of ... This study compares the calculated fracture apertures in a fragmented rock layer under different stress scenarios using two different approaches.Approach 1 is a simplified method using a two-dimensional(2D)mapping of the fracture network and projects the far-field stresses to individual fractures,and calculates the dilation,normal and shear displacements using experimental stiffnesses available in the literature.Approach 2 employs a three-dimensional(3D)finite element method(FEM)for the mechanical analysis of the fragmented rock layer considering the interaction with the neighbouring rock layers,frictional interfaces between the rock blocks,stress variations within the fragmented rock layer,and displacements,rotations and deformations of rock blocks.After calculating the fracture apertures using either of the approaches,the permeability of the fragmented rock layer is calculated by running flow simulations using the updated fracture apertures.The comparison between the results demonstrates an example of the inaccuracies that may exist in methods that use simplified assumptions such as 2D modelling,ignoring the block rotations and displacements,projected far-field stresses on fractures,and the stress variations within the rock layer.It is found that for the cases considered here,the permeability results based on apertures obtained from the simplified approach could be 40 times different from the results from apertures calculated using a full mechanical approach.Hence,3D mechanical modelling implementing realistic boundary conditions,while considering the displacements and rotations of rock blocks,is suggested for the calculation of apertures in fragmented rocks. 展开更多
关键词 FRACTURE APERTURE change In SITU stresses Frictional interfaces ENSEMBLE PERMEABILITY
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Electrospun and in situ self-polymerization of polyacrylonitrile containing gadolinium nanofibers for thermal neutron protection
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作者 Chun-Hong Wang Li-Min Hu +1 位作者 Zhi-Feng Wang Ming Zhang 《稀有金属:英文版》 SCIE EI CAS CSCD 2019年第3期252-258,共7页
In this work, the polyacrylonitrile containing gadolinium nanofibers for thermal neutron protection were successfully fabricated by electrospunning and followed by in situ self-polymerization. Scanning electron micros... In this work, the polyacrylonitrile containing gadolinium nanofibers for thermal neutron protection were successfully fabricated by electrospunning and followed by in situ self-polymerization. Scanning electron microscopy(SEM) and energy-dispersive spectroscopy(EDS) results show that there are no beads on the smooth surface of the nanofibers and gadolinium elements are uniformly dispersed in the matrix. The thermal analysis and FTIR results prove that gadolinium methacrylate is induced in situ selfpolymerization during the heat treatment. The leaching rate of Gd3+ decreases from 79.97% to 10.74% tested by lowfield nuclear magnetic resonance(LF-NMR) method after the self-polymerization of gadolinium methacrylate in the matrix when the nanofibers were immersed in water for7 days. The thermal neutron shielding analysis calculated by MCNP program shows that above 99% thermal neutrons are absorbed when traveling through the 2-mm-thick polyacrylonitrile containing gadolinium nanofibers. 展开更多
关键词 GADOLINIUM POLYACRYLONITRILE Electrospinning In situ SELF-POLYMERIZATION Thermal neutron SHIELDING
In situ observation of iron ore particle reduction above 1373K by confocal microscopy
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作者 Lei Guo Jin-tao Gao +2 位作者 Sheng-ping Zhong Qi-peng Bao Zhan-cheng Guo 《钢铁研究学报:英文版》 SCIE EI CAS CSCD 2019年第1期32-41,共10页
The reduction behavior of single iron ore particle was investigated at high temperatures(above 1373 K)with CO/CO2 mixture.A high-temperature laser scanning confocal microscope for in situ observation and a vertical qu... The reduction behavior of single iron ore particle was investigated at high temperatures(above 1373 K)with CO/CO2 mixture.A high-temperature laser scanning confocal microscope for in situ observation and a vertical quenching furnace for offline characterization were designed.The reduction process of ore particles at different temperatures and in different atmospheres was videoed using the confocal microscope.In the temperature range studied,the transformation of Fe2O3-FeO firstly occurred in the ore particles,and there was no metallic iron until the ore particles completely converted to FeG phase.During the formation of FeO phase,its crystal lattice transforms along the most close-packed direction of its close-packed plane(111).The gangue-rich area firstly melts during reduction around 1573 K.Above 1673 K,the iron ore particles melt and form spherical liquid drops with metallic iron in the center.The gas-based reduction behavior of iron ore particles above 1373K is deduced and graphically presented. 展开更多
关键词 In SITU observation Iron ORE PARTICLE REDUCTION Transformation Non-blast FURNACE
In situ preparation of well-dispersed CuO nanocatalysts in heavy oil for catalytic aquathermolysis
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作者 Ming Chen Chen Li +2 位作者 Guo-Rui Li Yan-Ling Chen Cheng-Gang Zhou 《石油科学:英文版》 SCIE CAS CSCD 2019年第2期439-446,共8页
We developed an in situ synthesis strategy for preparing well-dispersed CuO nanoparticles as aquathermolysis catalyst for viscosity reduction in Shengli heavy oil(China). A Cu(OH)2-contained microemulsion was employed... We developed an in situ synthesis strategy for preparing well-dispersed CuO nanoparticles as aquathermolysis catalyst for viscosity reduction in Shengli heavy oil(China). A Cu(OH)2-contained microemulsion was employed as a carrier to disperse the precursor Cu(OH)2 to the heavy oil phase. Under aquathermolysis condition(240 ℃, 2.5 MPa of N2), the Cu(OH)2 precursors would first be converted in situ to well-crystallized and size-homogeneous CuO nanoparticles naturally, catalyzed by which the viscosity of Shengli heavy oil could be reduced as much as 94.6%;simultaneously, 22.4% of asphaltenes were converted to light components. The agglomeration of the in situ prepared monoclinic CuO nanoparticles could be negligible throughout the catalytic reaction. Based on the characterization results of 1 H NMR, elemental analysis and GC-MS of oil samples before and after catalytic aquathermolysis, the mechanism for viscosity reduction of heavy oil in the catalytic system was investigated. 展开更多
关键词 Cu(OH)2-contained microemulsion In situ preparation CUO NANOCATALYST CATALYTIC viscosity reduction Heavy oil
Corneal re-innervation following refractive surgery treatments 预览
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作者 Francisco Bandeira Nur Zahira Yusoff +1 位作者 Gary Hin-Fai Yam Jodhbir Singh Mehta 《中国神经再生研究:英文版》 SCIE CAS CSCD 2019年第4期557-565,共9页
Laser refractive surgery is one of the most performed surgical procedures in the world.Although regarded safe and efficient,it has side effects.All of the laser based refractive surgical procedures invoke corneal nerv... Laser refractive surgery is one of the most performed surgical procedures in the world.Although regarded safe and efficient,it has side effects.All of the laser based refractive surgical procedures invoke corneal nerve injury to some degree.The impact of this denervation can range from mild discomfort to neurotrophic corneas.Currently,three techniques are widely used for laser vision correction:small incision lenticule extraction,laser-assisted keratomileusis in situ and photorefractive keratotomy.Each of these techniques affects corneal innervation differently and has a different pattern of nerve regeneration.The purpose of this review is to summarize the different underlying mechanisms for corneal nerve injury and compare the different patterns of corneal reinnervation. 展开更多
关键词 PHOTOREFRACTIVE KERATOTOMY small INCISION manual lenticule extraction laser-assisted KERATOMILEUSIS in situ refractive surgery in vivo confocal microscopy CORNEAL sensation CORNEAL nerve
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Genesis of the Bianjiadayuan PbeZn polymetallic deposit,Inner Mongolia,China: Constraints from in-situ sulfur isotope and trace element geochemistry of pyrite 预览
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作者 Kai-Rui Song Li Tang +7 位作者 Shou-Ting Zhang M. Santosh Christopher J. Spencer Yu Zhao Hao-Xing Li Liang Wang An-Li Zhang Yin-Qiang Sun 《地学前缘:英文版》 CAS CSCD 2019年第5期1863-1877,共15页
The Southern Great Xing’an Range (SGXR) which forms part of the eastern segment of the Central Asian Orogenic Belt (CAOB) is known as one of the most important Cu-Mo-Pb-Zn-Ag-Au metallogenic belts in China,hosting a ... The Southern Great Xing’an Range (SGXR) which forms part of the eastern segment of the Central Asian Orogenic Belt (CAOB) is known as one of the most important Cu-Mo-Pb-Zn-Ag-Au metallogenic belts in China,hosting a number of porphyry Mo (Cu),skarn Fe (Sn),epithermal Au-Ag,and hydrothermal veintype Ag-Pb-Zn ore deposits.Here we investigate the Bianjiadayuan hydrothermal vein-type Ag-Pb-Zn ore deposit in the southern part of the SGXR.Porphyry Sn ±Cu ± Mo mineralization is also developed to the west of the Ag-Pb-Zn veins in the ore field.We identify a five-stage mineralization process based on field and petrologic studies including (i) the early porphyry mineralization stage,(ii) main porphyry mineralization stage,(iii) transition mineralization stage,(iv) vein-type mineralization stage and (v) late mineralization stage.Pyrite is the predominant sulfide mineral in all stages except in the late mineralization stage,and we identify corresponding four types of pyrites: Py1 is medium-grained subhedral to euhedral occurring in the early barren quartz vein;Py2 is medium- to fine-grained euhedral pyrite mainly coexisting with molybdenite,chalcopyrite,minor sphalerite and galena;Py3 is fine-grained,subhedral to irregular pyrite and displays cataclastic textures with micro-fractures;Py4 occurs as euhedral microcrystals and forms irregularly shaped aggregate with sphalerite and galena.LA-ICP-MS trace element analyses of pyrite show that Cu,Pb,Zn,Ag,Sn,Cd and Sb are partitioned into pyrite as structurally bound metals or mineral micro/nano-inclusions,whereas Co,Ni,As and Se enter the lattice via isomorphism in all types of pyrite.The Cu,Zn,Ag,Cd concentrations gradually increase from Py1 to Py4,which we correlate with cooling and mixing of ore-forming fluid with meteoric water.Py2 contains the highest contents of Co,Ni,Se,Te and Bi,suggesting high temperature conditions for the porphyry mineralization stage.Ratios of Co/Ni (0.03-10.79,average 2.13) and sulphur isotope composition of sulfide indicate typical hydrothermal o 展开更多
关键词 Trace elements IN-SITU sulfur ISOTOPE PYRITE Bianjiadayuan deposit SOUTHERN Great Xing'an range
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Influence of Reaction Time on Growth Behaviours of Mg-Al LDH Films 预览
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作者 WU Liang CHEN Jing +5 位作者 ZHANG Sheng TANG Ai-tao YANG Dan-ni ZHANG Gen LIU Lei PAN Fu-sheng 《表面技术》 EI CAS CSCD 北大核心 2019年第3期19-26,共8页
Mg-Al LDH film was fabricated on anodized magnesium alloy AZ31 by in-situ growth method.The characteristics of the film were investigated by X-ray diffraction(XRD),Fourier transform infrared(FT-IR),scanning electron m... Mg-Al LDH film was fabricated on anodized magnesium alloy AZ31 by in-situ growth method.The characteristics of the film were investigated by X-ray diffraction(XRD),Fourier transform infrared(FT-IR),scanning electron microscopy(SEM)observation and electrochemical tests.The results showed that the crystallinity of LDH film was increased with reaction time.When the reaction time was more than 12 h,the LDH film had complete crystal layered structure.The anodic oxide film was sealed basically by the growth of LDH nanosheets after 6 h reaction.The corrosion resistance of the films became better with the increasing of reaction time.However,after 12 h reaction,the corrosion resistance of the film decreased.The formation behavior of the Mg-Al LDH film was proposed.That the competitive growth of LDH grains,which contains dissolution and recrystallization,was proposed to explain the change of the growth and corrosion resistance of the Mg-Al LDH film. 展开更多
关键词 magnesium alloy corrosion resistance in-situ GROWTH LAYERED double hydroxide(LDH) reaction time
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High-temperature investigation of mould slag crystallization by single and double hot thermocouple techniques
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作者 Nathalie Kolbl Irmtraud Marschall Harald Harmuth 《钢铁研究学报:英文版》 SCIE EI CAS CSCD 2019年第4期345-354,共10页
Methods for the characterization of mould slag crystallization with special emphasis on the single/double hot thermocouple technique(SHTT/DHTT)are reviewed.In the continuous casting process of steels,horizontal heat t... Methods for the characterization of mould slag crystallization with special emphasis on the single/double hot thermocouple technique(SHTT/DHTT)are reviewed.In the continuous casting process of steels,horizontal heat transfer is mainly influenced by the crystallization behaviour of the mould flux film.Here,both precipitation of crystals out of a liquid phase and devitrification of the glassy film in contact with the mould are of main interest.Therefore,various investigation methods are implemented to characterize different slag properties related to crystallization:a viscometer for determining the break temperature,differential thermal analysis(DTA),confocal scanning laser microscopy,and the water-cooled copper finger test.For near-service conditions,DHTT reveals the most detailed information,including not only the crystallization or devitrification temperature but also the morphology as well as the crystallization velocity.Due to improvements in the device and the representation of the results,a comparison of different samples is possible.Nevertheless,the application field of SHTT/DHTT is restricted to slag systems with low contents of evaporating components.Furthermore,the time required for data analysis is significantly longer than that required for other methods,e.g.DTA.Therefore,the application of DHTT is mainly advisable for mould slag research and development,whereas DTA can also be used for incoming inspections. 展开更多
关键词 SINGLE HOT THERMOCOUPLE TECHNIQUE DOUBLE HOT THERMOCOUPLE TECHNIQUE Mould slag Near-service condition In situ investigation CRYSTALLIZATION
Enhancing the observing capacity for the surface ocean by the use of Volunteer Observing Ship 预览
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作者 Zong-Pei Jiang Jiajun Yuan +1 位作者 Susan E.Hartman Wei Fan 《海洋学报:英文版》 SCIE CAS CSCD 2019年第7期114-120,共7页
Knowledge of the surface ocean dynamics and the underlying controlling mechanisms is critical to understand the natural variability of the ocean and to predict its future response to climate change.In this paper,we hi... Knowledge of the surface ocean dynamics and the underlying controlling mechanisms is critical to understand the natural variability of the ocean and to predict its future response to climate change.In this paper,we highlight the potential use of Volunteer Observing Ship(VOS),as carrier for automatic underway measuring system and as platform for sample collection,to enhance the observing capacity for the surface ocean.We review the concept,history,present status and future development of the VOS-based in situ surface ocean observation.The successes of various VOS projects demonstrate that,along with the rapid advancing sensor techniques,VOS is able to improve the temporal resolution and spatial coverage of the surface ocean observation in a highly cost-effective manner.A sustained and efficient marine monitoring system in the future should integrate the advantages of various observing platforms including VOS. 展开更多
关键词 VOLUNTEER observing SHIP SHIP of OPPORTUNITY SURFACE OCEAN in SITU observation sensor
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Revealing the crystallization process and realizing uniform 1.8 eV MA-based wide-bandgap mixed-halide perovskites via solution engineering
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作者 Yue-Min Xie Chunqing Ma +6 位作者 Xiuwen Xu Menglin Li Yuhui Ma Jing Wang Hrisheekesh Thachoth Chandran Chun-Sing Lee Sai-Wing Tsang 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第5期1033-1039,共7页
Wide-bandgap perovskites are recently drawing tremendous attention in the community for high-efficiency all-perovskite tandem solar cells.However,the formamidinium (FA^+) and methylammonium (MA^+) based wide-bandgap m... Wide-bandgap perovskites are recently drawing tremendous attention in the community for high-efficiency all-perovskite tandem solar cells.However,the formamidinium (FA^+) and methylammonium (MA^+) based wide-bandgap mixed halide perovskites suffered from high density of traps and pin-holes,respectively.Fundamental understanding on the crystallization and film formation processes are keys to overcome those challenges but not yet clearly understood.In this study,an in-situ photoluminescence technique was used to investigate the perovskite crystallization during the thermal annealing process.It is found that the crystallization of a mixed halide perovskite with bromide (Br^-) and iodine (I^-) ions following the Ostward ripening crystal growth.Interestingly,it is found that the initial nucleation reaction is quickly completed in the first few seconds,however,leaving the small crystals with inhomogeneous composition.The different aggregation affinities of such inhomogeneous small crystals provoke the formation of pin-holes during the thermal annealing process.By engineering the precursor solution to control the nucleation rate,the chemical composition of the small crystals has become homogenous.Uniform pin-hole free high Br-composited wide-bandgap MA0.9Cs0.1Pb(I0.6Br0.4)3 perovskite films with bandgap energy of 1.8 eV have been realized.The corresponding photovoltaic devices have achieved an encouraging device efficiency of 15.1% with superb photostability. 展开更多
关键词 in-situ photoluminance wide-bandgap perovskite pin-holes SOLUTION ENGINEERING
Evaluation of the SMOS and SMAP soil moisture products under different vegetation types against two sparse in situ networks over arid mountainous watersheds, Northwest China
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作者 Lanhui ZHANG Chansheng HE +1 位作者 Mingmin ZHANG Yi ZHU 《中国科学:地球科学英文版》 SCIE EI CAS CSCD 2019年第4期703-718,共16页
Assessment of the suitability of satellite soil moisture products at large scales is urgently needed for numerous climatic and hydrological researches, particularly in arid mountainous watersheds where soil moisture p... Assessment of the suitability of satellite soil moisture products at large scales is urgently needed for numerous climatic and hydrological researches, particularly in arid mountainous watersheds where soil moisture plays a key role in landatmosphere exchanges. This study presents evaluation of the SMOS(L2) and SMAP(L2_P_E and L2_P) products against ground-based observations from the Upstream of the Heihe River Watershed in situ Soil Moisture Network(UHRWSMN) and the Ecological and Hydrological Wireless Sensor Network(EHWSN) over arid high mountainous watersheds, Northwest China.Results show that all the three products are reliable in catching the temporal trend of the in situ observations at both point and watershed scales in the study area. Due to the uncertainty in brightness temperature and the underestimation of effective temperature, the SMOS L2 product and both the SMAP L2 products show "dry bias" in the high, cold mountainous area. Because of the more accurate brightness temperature observations viewing at a constant angle and more suitable estimations of single scattering albedo and optical depth, both the SMAP L2 products performed significantly better than the SMOS product.Moreover, comparing with station density of in situ network, station representation is much more important in the evaluation of the satellite soil moisture products. Based on our analysis, we propose the following suggestions for improvement of the SMOS and SMAP product suitability in the mountainous areas: further optimization of effective temperature;revision of the retrieval algorithm of the SMOS mission to reduce the topographic impacts;and, careful selection of in situ observation stations for better representation of in situ network in future evaluations. All these improvements would lead to better applicability of the SMOS and SMAP products for soil moisture estimation to the high elevation and topographically complex mountainous areas in arid regions. 展开更多
关键词 SMOS SMAP EVALUATION Different vegetation types SPARSE in situ NETWORKS ARID mountainous watershed
SiC/Al-Mg合金复合粉体制备及表征 预览
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作者 石春杰 焦宇鸿 《湖北工程学院学报》 2019年第3期15-20,共6页
以Si粉、酚醛树脂和Al-Mg为原料,采用原位自生工艺制备了SiC/Al-Mg复合粉体。用X射线衍射(XRD)、激光粒度分析、扫描电子显微镜(SEM)等手段,分析了粉体的组成、粒度分布和显微结构,结果表明:合金含量为30%,制备温度在800℃,球磨时间2h时... 以Si粉、酚醛树脂和Al-Mg为原料,采用原位自生工艺制备了SiC/Al-Mg复合粉体。用X射线衍射(XRD)、激光粒度分析、扫描电子显微镜(SEM)等手段,分析了粉体的组成、粒度分布和显微结构,结果表明:合金含量为30%,制备温度在800℃,球磨时间2h时,能够得到颗粒尺寸小于10μm,SiC为主相的复合粉体。影响粉体颗粒尺寸的主要原因是合金的含量,其次是球磨工艺和制备温度等工艺因素。所生成的SiC尺寸在200~400nm,与基体具有较好的润湿性,经过研磨后,很少有颗粒从基体中脱落。该工艺为解决SiC与基体合金之间的润湿性和界面反应的问题提供了新方法。 展开更多
关键词 SIC 复合粉体 原位自生 制备 表征
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