期刊文献+
共找到1,183篇文章
< 1 2 60 >
每页显示 20 50 100
Influence of Calcium Sulfate State and Fineness of Cement on Hydration of Portland Cements Using Electrical Measurement 被引量:2
1
作者 魏小胜 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2006年第4期141-145,共5页
The influence of calcium sulfate state and fineness of cement on hydration of Portland cement was studied using electrical resistivity measurement. The bulk resistivity curve of the paste from the abnormal cement main... The influence of calcium sulfate state and fineness of cement on hydration of Portland cement was studied using electrical resistivity measurement. The bulk resistivity curve of the paste from the abnormal cement mainly with hemihydrate had a characteristic abnormal peak and rapid increase in early period. The resistivity measurement technique can be used to discriminate abnormal setting. For normal cement with gypsum, the increase in fineness of the Portland cement decreases the minimum resistivhy due to a higher ionic concentration and increases the 24 hour resistivity due to a reduction in macroscopic pore size. The setting time, compressive strength, pore structure of pastes made from different cements were carried out to compare the influence of water to cement ratio, calcium sulfate state and fineness. It is found that the electrical and mechanical properties are strongly affected by the initial porosity, the presence of hemihydrate or gypsum, and the fineness of cement. 展开更多
关键词 false setting electrical resistivity fineness HYDRATION
下载PDF
Improvements of Fiber Yield and Fiber Fineness by Expressing the iaaM Gene in Cotton Seed Coat 被引量:3
2
作者 PEI Yan,ZHENG Xue-lian,ZHANG Mi,ZENG Qi-wei,HOU Lei(Key Laboratory of Biotechnology and Crop Quality Improvement of Ministry of Agriculture of China,Biotechnology Research Center,Southwest University,Chongqing 400716,P.R.China) 《棉花学报》 CSCD 北大核心 2008年第S1期44-,共1页
Cotton,the most important natural fiber crop in the world,is a mainstay in China's economy.However,for over two decades,cotton yields both in China and U.S.have been at a plateau.
关键词 FBP Improvements of Fiber Yield and Fiber fineness by Expressing the iaaM Gene in Cotton Seed Coat
下载PDF
Effects of slag fineness on durability of mortars 被引量:1
3
作者 TOPU lker Bekir BLR Turhan 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第11期1725-1730,共6页
In recent years, the usages of by-products and wastes in industry have become more important. The importance of the sustainable development is also of increasing. The utilizations of wastes, as mineral admixture or fi... In recent years, the usages of by-products and wastes in industry have become more important. The importance of the sustainable development is also of increasing. The utilizations of wastes, as mineral admixture or fine aggregate, reduce the consumption of the natural resources and improve the durability of concrete. In this study, the effect of the fineness on the high temperature and sulphate resistances of concrete mortar specimens, produced with ground granulated blast-furnace slag (GBFS) replacing cement, is investigated. The compressive and flexural strength test results for all series related to durability effects, exposing temperature and solutions, exposure times for these durability effects, slag content and fineness are discussed. Conse- quently, the optimum slag contents are determined for producing the sulphate and high temperature resistant mortars. 展开更多
关键词 CEMENT fineness Ground slag High temperature effect Sulphate attack Sustainable development
下载PDF
Effect of trace Ti and Y on mechanical properties of Au-based alloys with 990 fineness
4
作者 YANGQingqing XIONGWeihao ZHANGJie 《Rare Metals》 SCIE EI CAS CSCD 2005年第2期178-184,共7页
The effect of trace Ti and Y on Au-based alloys with 990 fineness has beeninvestigated systematically by means of tensile test, hardness test, scanning and transmissionelectron microscopic analyses. These experimental... The effect of trace Ti and Y on Au-based alloys with 990 fineness has beeninvestigated systematically by means of tensile test, hardness test, scanning and transmissionelectron microscopic analyses. These experimental results show that trace Ti and Y can significantlyimprove the mechanical properties of Au-based alloys with 990 fineness because Ti and Y cansignificantly refine matrix grains, and solid solution strengthening, work strengthening andprecipitation strengthening occur during mechanical heat treatment. 展开更多
关键词 Au-based aloys with 990 fineness mechanical properties TI Y
下载PDF
Effect of Content and Fineness of GGBS on Pore Structure of Cement Paste
5
作者 DAI Jinpeng WANG Qicai +2 位作者 ZHANG Xin BI Ruixiao DU Wentao 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2022年第5期933-947,共15页
The effect of the content and specific surface area of the ground granulated blast furnace slag (GGBS) on the pore structure of the cement paste was determined through the low-field nuclear magnetic resonance (NMR).Th... The effect of the content and specific surface area of the ground granulated blast furnace slag (GGBS) on the pore structure of the cement paste was determined through the low-field nuclear magnetic resonance (NMR).The Pearson correlation analysis method was used to calculate the correlation coefficient between the porosity and age of cement paste,the specific surface area of GGBS and the content of GGBS.The test results exhibited that the porosity of the cement paste with different ageing durations gradually decreased on increasing the content and specific surface area of GGBS.The content and specific surface area of GGBS had a negligible effect on the 1-10 nm size gel pores in the cement paste,whereas,had a significant effect on the 10-100 nm size capillary pores.In addition,these parameters did not affect the final most probable pore size of the cement paste.The correlation between age and porosity was the largest,and the correlation between GGBS content and porosity was greater than that between GGBS specific surface area and porosity.Moreover,a modified pore structure model was successfully developed to effectively predict the pore structure of the GGBS based cement paste. 展开更多
关键词 ground granulated blast furnace slag pore structure fineness cement paste low-field nuclear magnetic resonance
下载PDF
Blending Fineness Ratio of Fibers for Spinning Fine Denier Fibers
6
作者 程隆棣 《Journal of China Textile University(English Edition)》 EI CAS 2000年第1期47-50,共4页
The paper deals with the theoretic relationship betweenfineness of man-made fibers blended with natural fibersand regularities of the yarns made from them.Throughestablishment of the theory model and digitally analysi... The paper deals with the theoretic relationship betweenfineness of man-made fibers blended with natural fibersand regularities of the yarns made from them.Throughestablishment of the theory model and digitally analysisusing Matlab software,the optimum fineness of the fi-bers could be figured out. 展开更多
关键词 BLENDED spining RATIO of the fineness of the fi-bers irregularity.
下载PDF
A Survey of Sediment Fineness and Moisture Content in the Soyang Lake Floodplain Using GPS Data
7
作者 Mutiara Syifa Prima Riza Kadavi +1 位作者 Sung Jae Park Chang-Wook Lee 《Engineering》 SCIE EI 2021年第2期252-259,共8页
Soyang Lake is the largest lake in Republic of Korea bordering Chuncheon,Yanggu,and Inje in Gangwon Province.It is widely used as an environmental resource for hydropower,flood control,and water supply.Therefore,we co... Soyang Lake is the largest lake in Republic of Korea bordering Chuncheon,Yanggu,and Inje in Gangwon Province.It is widely used as an environmental resource for hydropower,flood control,and water supply.Therefore,we conducted a survey of the floodplain of Soyang Lake to analyze the sediments in the area.We used global positioning system(GPS)data and aerial photography to monitor sediment deposits in the Soyang Lake floodplain.Data from three GPS units were compared to determine the accuracy of sampling location measurement.Sediment samples were collected at three sites:two in the eastern region of the floodplain and one in the western region.A total of eight samples were collected:Three samples were collected at 10 cm intervals to a depth of 30 cm from each site of the eastern sampling point,and two samples were collected at depths of 10 and 30 cm at the western sampling point.Samples were collected and analyzed for vertical and horizontal trends in particle size and moisture content.The sizes of the sediment samples ranged from coarse to very coarse sediments with a negative slope,which indicate eastward movement from the breach.The probability of a breach was indicated by the high water content at the eastern side of the floodplain,with the eastern sites showing a higher probability than the western sites.The results of this study indicate that analyses of grain fineness,moisture content,sediment deposits,and sediment removal rates can be used to understand and predict the direction of breach movement and sediment distribution in Soyang Lake. 展开更多
关键词 Soyang Lake Grain fineness number Moisture content GPS data Digital surface model
下载PDF
Photoelectric Measurement of the Fineness of Raw Silk
8
作者 费万春 《Journal of Measurement Science and Instrumentation》 CAS 2010年第3期205-207,共3页
In order to precisely measure the diameters for obtaining the fineness of rolling raw silk, the physical features of raw silk are analyzed. By means of Fresnel principle, diffractions caused by different transparent r... In order to precisely measure the diameters for obtaining the fineness of rolling raw silk, the physical features of raw silk are analyzed. By means of Fresnel principle, diffractions caused by different transparent raw silk filaments are analyzed and simulated. Image data of raw silk filament measured by digital CMOS camera are analyzed and processed for obtaining the precise diameters of the filamerit with the relative error of less than 1%. On the assumption of appropriate elliptic cross-section of the filament, the cross-section area is calculated as the fineness of the filament. Measurement experiments are carded out. Finally, some suggestions are proposed for photoelectric measuring the fineness of raw silk. 展开更多
关键词 fineness of raw silk photoelectric measurement SIMULATION image processing
下载PDF
Effects of feeding rate and formula fineness degree of ring die pellet mill on mechanical property, physical quality, energy requirements, and production cost of poultry diets
9
作者 Khaled A.Metwally Reda I.Zaki +5 位作者 Sally S.Fouda Reem S.Alruhaimi Haifa A.Alqhtani Nouf Aldawood Ayman M.Mahmoud Mohammed A.E.Naiel 《International Journal of Agricultural and Biological Engineering》 SCIE 2023年第3期30-36,共7页
The effect of a machine feeding rate(FR;1,1.5 and 2 Mg/h)and/or three levels of selected fineness degree(FD;3,5 and 7 mm)on machine performance,pellet physical parameters,required energy and production cost of three m... The effect of a machine feeding rate(FR;1,1.5 and 2 Mg/h)and/or three levels of selected fineness degree(FD;3,5 and 7 mm)on machine performance,pellet physical parameters,required energy and production cost of three main types of broilers diets were examined in this experiment.The examined broiler diets were formulated to meet the Ross 308 strain requirements.A complete factorial design(3×3×3)was used to identify the effects of studied factors on the pellet mill machine and pellet production.The obtained results indicated that the pellet mill productivity significantly(p˂0.001)improved through increased pellet mill feeding rate level.In addition,the machine pelleting efficiency was found to be significantly affected by all studied variables and their interactions.While the total power consumption of the machine showed no variations under the impact of the tested factors or with any of their combinations.Regarding the pellet physical quality indices,all broiler diets with all selected FD and lower FR had the maximum durability and bulk density levels.Furthermore,lower feeding rates were associated with higher hardness degrees.The lowest production costs were substantially correlated with high FR and intermediate FD(5 mm).Furthermore,production costs were determined to be reduced in finisher broiler diets under different feeding rates.Moreover,manufacturing costs of finisher broiler meals were observed to decrease in several feeding rates.Overall,these findings indicate the capabilities of producing high-quality pellets and reducing the needed production costs by optimizing feeding rates to 2 Mg/h and 2 mm fineness in broiler diets. 展开更多
关键词 feeding rate fineness degree broiler diets pellet quality production cost
原文传递
Structural properties of residual carbon in coal gasification fine slag and their influence on flotation separation and resource utilization:A review 被引量:4
10
作者 Rui Han Anning Zhou +4 位作者 Ningning Zhang Kaiqiang Guo Mengyan Cheng Heng Chen Cuicui Li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第2期217-230,共14页
Coal gasification fine slag(FS)is a typical solid waste generated in coal gasification.Its current disposal methods of stockpil-ing and landfilling have caused serious soil and ecological hazards.Separation recovery a... Coal gasification fine slag(FS)is a typical solid waste generated in coal gasification.Its current disposal methods of stockpil-ing and landfilling have caused serious soil and ecological hazards.Separation recovery and the high-value utilization of residual carbon(RC)in FS are the keys to realizing the win-win situation of the coal chemical industry in terms of economic and environmental benefits.The structural properties,such as pore,surface functional group,and microcrystalline structures,of RC in FS(FS-RC)not only affect the flotation recovery efficiency of FS-RC but also form the basis for the high-value utilization of FS-RC.In this paper,the characteristics of FS-RC in terms of pore structure,surface functional groups,and microcrystalline structure are sorted out in accordance with gasification type and FS particle size.The reasons for the formation of the special structural properties of FS-RC are analyzed,and their influence on the flotation separation and high-value utilization of FS-RC is summarized.Separation methods based on the pore structural characterist-ics of FS-RC,such as ultrasonic pretreatment-pore-blocking flotation and pore breaking-flocculation flotation,are proposed to be the key development technologies for improving FS-RC recovery in the future.The design of low-cost,low-dose collectors containing polar bonds based on the surface and microcrystalline structures of FS-RC is proposed to be an important breakthrough point for strengthening the flotation efficiency of FS-RC in the future.The high-value utilization of FS should be based on the physicochemical structural proper-ties of FS-RC and should focus on the environmental impact of hazardous elements and the recyclability of chemical waste liquid to es-tablish an environmentally friendly utilization method.This review is of great theoretical importance for the comprehensive understand-ing of the unique structural properties of FS-RC,the breakthrough of the technological bottleneck in the efficient flotation separation of FS,and the expansion of the field of the high value-added utilization of FS-RC. 展开更多
关键词 coal gasification fine slag residual carbon pore structure surface functional groups microcrystalline structure flotation sep-aration resource utilization
下载PDF
Diagnostic and therapeutic role of endoscopic ultrasound in liver diseases:A systematic review and meta-analysis 被引量:4
11
作者 Eyad Gadour Abeer Awad +3 位作者 Zeinab Hassan Khalid Jebril Shrwani Bogdan Miutescu Hussein Hassan Okasha 《World Journal of Gastroenterology》 SCIE CAS 2024年第7期742-758,共17页
BACKGROUND In hepatology,the clinical use of endoscopic ultrasound(EUS)has experienced a notable increase in recent times.These applications range from the diagnosis to the treatment of various liver diseases.Therefor... BACKGROUND In hepatology,the clinical use of endoscopic ultrasound(EUS)has experienced a notable increase in recent times.These applications range from the diagnosis to the treatment of various liver diseases.Therefore,this systematic review summarizes the evidence for the diagnostic and therapeutic roles of EUS in liver diseases.AIM To examine and summarize the current available evidence of the possible roles of the EUS in making a suitable diagnosis in liver diseases as well as the therapeutic accuracy and efficacy.METHODS PubMed,Medline,Cochrane Library,Web of Science,and Google Scholar databases were extensively searched until October 2023.The methodological quality of the eligible articles was assessed using the Newcastle-Ottawa scale or Cochrane Risk of Bias tool.In addition,statistical analyses were performed using the Comprehensive Meta-Analysis software.RESULTS Overall,45 articles on EUS were included(28 on diagnostic role and 17 on therapeutic role).Pooled analysis demonstrated that EUS diagnostic tests had an accuracy of 92.4%for focal liver lesions(FLL)and 96.6%for parenchymal liver diseases.EUS-guided liver biopsies with either fine needle aspiration or fine needle biopsy had low complication rates when sampling FLL and parenchymal liver diseases(3.1%and 8.7%,respectively).Analysis of data from four studies showed that EUS-guided liver abscess had high clinical(90.7%)and technical success(90.7%)without significant complications.Similarly,EUS-guided interventions for the treatment of gastric varices(GV)have high technical success(98%)and GV obliteration rate(84%)with few complications(15%)and rebleeding events(17%).CONCLUSION EUS in liver diseases is a promising technique with the potential to be considered a first-line therapeutic and diagnostic option in selected cases. 展开更多
关键词 Focal liver lesion Liver abscess drainage Fine needle aspiration Gastric varices Endoscopic ultrasound
下载PDF
Contrast-enhanced guided endoscopic ultrasound procedures 被引量:1
12
作者 Marcel Ioan Gheorghiu Andrada Seicean +3 位作者 Cristina Pojoga Claudia Hagiu Radu Seicean Zeno Sparchez 《World Journal of Gastroenterology》 SCIE CAS 2024年第17期2311-2320,共10页
Contrast-enhanced endoscopic ultrasound(CH-EUS)can overcome the limi-tations of endoscopic ultrasound-guided acquisition by identifying microvessels inside inhomogeneous tumours and improving the characterization of t... Contrast-enhanced endoscopic ultrasound(CH-EUS)can overcome the limi-tations of endoscopic ultrasound-guided acquisition by identifying microvessels inside inhomogeneous tumours and improving the characterization of these tumours.Despite the initial enthusiasm that oriented needle sampling under CH-EUS guidance could provide better diagnostic yield in pancreatic solid lesions,further studies did not confirm the supplementary values in cases of tissue acquisition guided by CH-EUS.This review details the knowledge based on the available data on contrast-guided procedures.The indications for CH-EUS tissue acquisition include isoechoic EUS lesions with poor visible delineation where CH-EUS can differentiate the lesion vascularisation from the surrounding parenchyma and also the mural nodules within biliopancreatic cystic lesions,which occur in select cases.Additionally,the roles of CH-EUS-guided therapy in patients whose pancreatic fluid collections or bile ducts that have an echogenic content have indications for drainage,and patients who have nonvisualized vessels that need to be highlighted via Doppler EUS are presented.Another indication is represented if there is a need for an immediate assessment of the post-radiofrequency ablation of pancreatic neuroendocrine tumours,in which case CH-EUS can be used to reveal the incomplete tumour destruction. 展开更多
关键词 ENDOSONOGRAPHY Contrast-enhanced endoscopic ultrasound Tissue acquisition Fine needle aspiration Fine needle biopsy Drainage Pancreatic fluid collections BIOPSY PANCREAS
下载PDF
Influence of topography on the fine structures of stratospheric gravity waves:An analysis using COSMIC-2 temperature data 被引量:1
13
作者 JiaRui Wei Xiao Liu +2 位作者 JiYao Xu QinZeng Li Hong Gao 《Earth and Planetary Physics》 EI CAS CSCD 2024年第3期497-513,共17页
We derive the potential energy of gravity waves(GWs)in the upper troposphere and stratosphere at 45°S-45°N from December 2019 to November 2022 by using temperature profiles retrieved from the Constellation O... We derive the potential energy of gravity waves(GWs)in the upper troposphere and stratosphere at 45°S-45°N from December 2019 to November 2022 by using temperature profiles retrieved from the Constellation Observing System for Meteorology,Ionosphere,and Climate-2(COSMIC-2)satellite.Owing to the dense sampling of COSMIC-2,in addition to the strong peaks of gravity wave potential energy(GWPE)above the Andes and Tibetan Plateau,we found weak peaks above the Rocky,Atlas,Caucasus,and Tianshan Mountains.The land-sea contrast is responsible for the longitudinal variations of the GWPE in the lower and upper stratosphere.At 40°N/S,the peaks were mainly above the topographic regions during the winter.At 20°N/S,the peaks were a slight distance away from the topographic regions and might be the combined effect of nontopographic GWs and mountain waves.Near the Equator,the peaks were mainly above the regions with the lowest sea level altitude and may have resulted from convection.Our results indicate that even above the local regions with lower sea level altitudes compared with the Andes and Tibetan Plateau,the GWPE also exhibits fine structures in geographic distributions.We found that dissipation layers above the tropopause jet provide the body force to generate secondary waves in the upper stratosphere,especially during the winter months of each hemisphere and at latitudes of greater than 20°N/S. 展开更多
关键词 TOPOGRAPHY fine structures stratospheric gravity waves Constellation Observing System for Meteorology Ionosphere and Climate-2(COSMIC-2) dissipation layers
下载PDF
The ITZ microstructure,thickness,porosity and its relation with compressive and flexural strength of cement mortar;influence of cement fineness and water/cement ratio 被引量:1
14
作者 Tahereh KOROUZHDEH Hamid ESKANDARI-NADDAF Ramin KAZEMI 《Frontiers of Structural and Civil Engineering》 SCIE EI CSCD 2022年第2期191-201,共11页
A new insight into the interfacial transition zone(ITZ)in cement mortar specimens(CMSs)that is influenced by cement fineness is reported.The importance of cement fineness in ITZ characterizations such as morphology an... A new insight into the interfacial transition zone(ITZ)in cement mortar specimens(CMSs)that is influenced by cement fineness is reported.The importance of cement fineness in ITZ characterizations such as morphology and thickness is elucidated by backscattered electron images and by consequences to the compressive(Fc)and flexural strength(Ff),and porosity at various water/cement ratios.The findings indicate that by increasing the cement fineness the calcium silicate hydrate formation in the ITZ is favored and that this can refine the pore structures and create a denser and more homogeneous microstructure.By increasing cement fineness by about 25%of,the ITZ thickness of CMSs was reduced by about 30%and Fc was increased by 7%–52%and Ff by 19%–40%.These findings illustrate that the influence of ITZ features on the mechanical strength of CMSs is mostly related to the cement fineness and ITZ microstructure. 展开更多
关键词 cement fineness interfacial transition zone compressive and flexural strength
原文传递
Multiscale analysis of fine slag from pulverized coal gasification in entrained-flow bed
15
作者 Lirui Mao Mingdong Zheng +5 位作者 Baoliang Xia Facun Jiao Tao Liu Yuanchun Zhang Shengtao Gao Hanxu Li 《International Journal of Coal Science & Technology》 EI CAS CSCD 2024年第1期119-132,共14页
Fine slag(FS)is an unavoidable by-product of coal gasification.FS,which is a simple heap of solid waste left in the open air,easily causes environmental pollution and has a low resource utilization rate,thereby restri... Fine slag(FS)is an unavoidable by-product of coal gasification.FS,which is a simple heap of solid waste left in the open air,easily causes environmental pollution and has a low resource utilization rate,thereby restricting the development of energy-saving coal gasification technologies.The multiscale analysis of FS performed in this study indicates typical grain size distribution,composition,crystalline structure,and chemical bonding characteristics.The FS primarily contained inorganic and carbon components(dry bases)and exhibited a"three-peak distribution"of the grain size and regular spheroidal as well as irregular shapes.The irregular particles were mainly adsorbed onto the structure and had a dense distribution and multiple pores and folds.The carbon constituents were primarily amorphous in structure,with a certain degree of order and active sites.C 1s XPS spectrum indicated the presence of C–C and C–H bonds and numerous aromatic structures.The inorganic components,constituting 90%of the total sample,were primarily silicon,aluminum,iron,and calcium.The inorganic components contained Si–O-Si,Si–O–Al,Si–O,SO_(4)^(2−),and Fe–O bonds.Fe 2p XPS spectrum could be deconvoluted into Fe 2p_(1/2) and Fe 2p_(3/2) peaks and satellite peaks,while Fe existed mainly in the form of Fe(III).The findings of this study will be beneficial in resource utilization and formation mechanism of fine slag in future. 展开更多
关键词 Coal gasification Fine slag Multiscale analysis Carbon components Inorganic components
下载PDF
Evolution history dominantly regulates fine root lifespan in tree species across the world
16
作者 Xingzhao Huang Zhouying Lu +6 位作者 Fangbing Li Yang Deng Fangfang Wan Quancheng Wang Fousseni Folega Jinsong Wang Zijian Guo 《Forest Ecosystems》 SCIE CSCD 2024年第4期516-525,共10页
Understanding the drivers of variations in fine root lifespan is key to informing nutrient cycling and productivity in terrestrial ecosystems.However,the general patterns and determinants of forest fine root lifespan ... Understanding the drivers of variations in fine root lifespan is key to informing nutrient cycling and productivity in terrestrial ecosystems.However,the general patterns and determinants of forest fine root lifespan at the global scale are still limited.We compiled a dataset of 421 fine root lifespan observations from 76 tree species globally to assess phylogenetic signals among species,explored relationships between fine root lifespan and biotic and abiotic factors,and quantified the relative importance of phylogeny,root system structure and functions,climatic and edaphic factors in driving global fine root lifespan variations.Overall,fine root lifespan showed a clear phylogenetic signal,with gymnosperms having a longer fine root lifespan than angiosperms.Fine root lifespan was longer for evergreens than deciduous trees.Ectomycorrhizal(ECM)plants had an extended fine root lifespan than arbuscular mycorrhizal(AM)plants.Among different climatic zones,fine root lifespan was the longest in the boreal zone,while it did not vary between the temperate and tropical zone.Fine root lifespan increased with soil depth and root order.Furthermore,the analysis of relative importance indicated that phylogeny was the strongest driver influencing the variation in forest fine root lifespan,followed by soil clay content,root order,mean annual temperature,and soil depth,while other environmental factors and root traits exerted weaker effects.Our results suggest that the global pattern of fine root lifespan in forests is shaped by the interplay of phylogeny,root traits and environmental factors.These findings necessitate accurate representations of tree evolutionary history in earth system models to predict fine root longevity and its responses to global changes. 展开更多
关键词 Fine root lifespan Trees PHYLOGENY Root order Soil property Climatic factors
下载PDF
Mechanical Behavior Based on Aggregates Microstructure of Ultra-high Performance Concrete
17
作者 丁庆军 ZHOU Changsheng +4 位作者 张高展 GUO Hong LI Yang ZHANG Yongyuan GUO Kaizheng 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第3期673-681,共9页
We developed ultra-high performance concrete(UHPC)incorporating mullite sand and brown corundum sand(BCS),and the quartz sand UHPC was utilized to prepare for comparison.The properties of compressive strength,elastic ... We developed ultra-high performance concrete(UHPC)incorporating mullite sand and brown corundum sand(BCS),and the quartz sand UHPC was utilized to prepare for comparison.The properties of compressive strength,elastic modulus,ultrasonic pulse velocity,flexural strength,and toughness were investigated.Scanning electron microscopy and nanoindentation were also conducted to reveal the underlying mechanisms affecting macroscopic performance.Due to the superior interface bonding properties between mullite sand and matrix,the compressive strength and flexural toughness of UHPC have been significantly improved.Mullite sand and BCS aggregates have higher stiffness than quartz sand,contributing to the excellent elastic modulus exhibited by UHPC.The stiffness and volume of aggregates have a more significant impact on the elastic modulus of UHPC than interface performance,and the latter contributes more to the strength of UHPC.This study will provide a reference for developing UHPC with superior elastic modulus for structural engineering. 展开更多
关键词 ultra-high performance concrete mechanical properties fine aggregates MICROSTRUCTURE NANOINDENTATION
下载PDF
Fine mapping of two recessive genes TaFLA1 and TaSPL8 controlling flag leaf angle in bread wheat
18
作者 Qiushi Wang Jiaxing Bai +11 位作者 Hongchun Xiong Yongdun Xie Chaojie Wang Jiayu Gu Linshu Zhao Huiyuan Li Jinfeng Zhang Shirong Zhao Yuping Ding Zhengwu Fang Huijun Guo Luxiang Liu 《The Crop Journal》 SCIE CSCD 2024年第4期1159-1167,共9页
Flag leaf angle is one of the key target traits in high yield wheat breeding.A smaller flag leaf angle reduces shading and enables plants to grow at a higher density,which increases yield.Here we identified a mutant,j... Flag leaf angle is one of the key target traits in high yield wheat breeding.A smaller flag leaf angle reduces shading and enables plants to grow at a higher density,which increases yield.Here we identified a mutant,je0407,with an 84.34%-89.35%smaller flag leaf angle compared with the wild type.The mutant also had an abnormal lamina joint and no ligule or auricle.Genetic analysis indicated that the ligule was controlled by two recessive genes,which were mapped to chromosomes 2AS and 2DL.The mutant allele on chromosome 2AS was named Tafla1b,and it was fine mapped to a 1 Mb physical interval.The mutant allele on chr.2DL was identified as Taspl8b,a novel allele of TaSPL8 with a missense mutation in the second exon,which was used to develop a cleaved amplified polymorphic sequence marker.F3 and F4 lines derived from crosses between Jing411 and je0407 were genotyped to investigate interactions between the Tafla1b and Taspl8b alleles.Plants with the Tafla1b/Taspl8a genotype had 58.41%-82.76%smaller flag leaf angles,6.4%-24.9%shorter spikes,and a greater spikelet density(0.382 more spikelets per cm)compared with the wild type.Plants with the Tafla1a/Taspl8b genotype had 52.62%-82.24%smaller flag leaf angles and no differences in plant height or spikelet density compared with the wild type.Tafla1b/Taspl8b plants produced erect leaves with an abnormal lamina joint.The two alleles had dosage effects on ligule formation and flag leaf angle,but no significant effect on thousand-grain weight.The mutant alleles provide novel resources for improvement of wheat plant architecture. 展开更多
关键词 WHEAT Ligule Flag leaf angle Fine mapping Tafla1 Taspl8
下载PDF
Fine mapping of the powdery mildew resistance gene PmXQ-0508 in bread wheat
19
作者 Zejun Qian Guohao Han +11 位作者 Ningning Yu Cheng Liu Ran Han Paula E.Jameson Jiaojiao Wang Ya Zhao Bei Xiao Ruishan Liu Jiadong Zhang Yuli Jin Hongjie Li Pengtao Ma 《The Crop Journal》 SCIE CSCD 2024年第4期1176-1184,共9页
In a wheat breeding line XQ-0508 showing consistent resistance to powdery mildew disease,a recessive gene,designated PmXQ-0508,was identified and mapped to a distal region on chromosome arm 2BS.Of three resistance-ass... In a wheat breeding line XQ-0508 showing consistent resistance to powdery mildew disease,a recessive gene,designated PmXQ-0508,was identified and mapped to a distal region on chromosome arm 2BS.Of three resistance-associated genes in this region,one encoding a protein kinase was selected as the primary candidate for PmXQ-0508.Ten closely linked DNA markers developed in the study could be used for marker-assisted selection for powdery-mildew resistance in breeding programs. 展开更多
关键词 Wheat powdery mildew PmXQ-0508 BSR-Seq Fine mapping Marker-assisted selection
下载PDF
Effects of dry-wet cycles on the mechanical properties of sandstone with unloading-induced damage
20
作者 NAN Gan ZHANG Jiaming +2 位作者 LUO Yi WANG Xinlong HU Zhongyi 《Journal of Mountain Science》 SCIE CSCD 2024年第10期3474-3486,共13页
Sandstone is the fundamental material in various engineering and construction projects.However,the mechanical integrity of sandstone can be compromised by initial unloading damage resulting from activities such as eng... Sandstone is the fundamental material in various engineering and construction projects.However,the mechanical integrity of sandstone can be compromised by initial unloading damage resulting from activities such as engineering excavations.Furthermore,this degradation is further exacerbated under periodic dry-wet environmental conditions.This study investigated the effects of dry-wet cycles and unloading on the mechanical properties of jointed fine sandstone using uniaxial and triaxial compression tests.These tests were performed on rock samples subjected to varying unloading degrees and different numbers of dry-wet cycles.The results demonstrate that with an increase in the unloading degree from 0%to 70%,there is a corresponding decrease in peak stress ranging from 10%to 33%.Additionally,the cohesion exhibits a reduction of approximately 20%to 25%,while the internal friction angle experiences a decline of about 3.5%to 6%.These findings emphasize a significant unloading effect.Moreover,the degree of peak stress degradation in unloading jointed fine sandstone diminishes with an increase in confining pressure,suggesting that confining pressure mitigates the deterioration caused by dry-wet cycles.Additionally,as the number of dry-wet cycles increases,there is a notable decline in the mechanical properties of the sandstone,evidencing significant dry-wet degradation.Utilizing the Drucker Prager criterion,this study establishes a strength criterion and fracture criterion,denoted as σ_(1)(m,n) and K_(T)^(Ⅱ)(m, n), to quantify the combined impacts of dry-wet cycles and unloading on jointed fine sandstone,which provides a comprehensive understanding of its mechanical behavior under such conditions. 展开更多
关键词 UNLOADING Dry-wet cycle Jointed fine sandstone Strength criterion fracture criterion Mechanical properties
下载PDF
上一页 1 2 60 下一页 到第
使用帮助 返回顶部