期刊文献+
共找到158,253篇文章
< 1 2 250 >
每页显示 20 50 100
Influence of secondary lining thickness on mechanical behaviours of double-layer lining in large-diameter shield tunnels
1
作者 Shimin Wang Xuhu He +3 位作者 Xiaoyu Peng Ya Wang Zhengxin Li Zihan 《Underground Space》 SCIE EI CSCD 2024年第5期130-150,共21页
In large-diameter shield tunnels,applying the double-layer lining structure can improve the load-bearing properties and maintain the stability of segmental lining.The secondary lining thickness is a key parameter in t... In large-diameter shield tunnels,applying the double-layer lining structure can improve the load-bearing properties and maintain the stability of segmental lining.The secondary lining thickness is a key parameter in the design of a double lining structure,which is worth being explored.Based on an actual large-diameter shield tunnel,loading model tests are carried out to investigate the effect of the secondary lining thickness on the mechanical behaviours of the double lining structure.The test results show that within the range of secondary lining thicknesses discussed,the load-bearing limit of the double-layer lining increases with growing secondary lining thickness.As a passive support,the secondary lining acts as an auxiliary load-bearing structure by contacting the segment.And changes in secondary lining thickness have a significant effect on the contact state between the segment and secondary lining,with both the contact pressure level and the contact area between the two varying.For double-layer lining structures in large-diameter shield tunnels,it is proposed that the stiffness of the secondary lining needs to be matched to the stiffness of the segment,as this allows them to have a coordinated deformation and a good joint load-bearing effect. 展开更多
关键词 Large-diameter shield tunnels double-layer lining structure Secondary lining thickness Stiffness matching Similar model test
原文传递
Jet formation and penetration performance of a double-layer charge liner with chemically-deposited tungsten as the inner liner 被引量:2
2
作者 Bihui Hong Wenbin Li +2 位作者 Yiming Li Zhiwei Guo Binyou Yan 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期374-385,共12页
This paper proposes a type of double-layer charge liner fabricated using chemical vapor deposition(CVD)that has tungsten as its inner liner.The feasibility of this design was evaluated through penetration tests.Double... This paper proposes a type of double-layer charge liner fabricated using chemical vapor deposition(CVD)that has tungsten as its inner liner.The feasibility of this design was evaluated through penetration tests.Double-layer charge liners were fabricated by using CVD to deposit tungsten layers on the inner surfaces of pure T2 copper liners.The microstructures of the tungsten layers were analyzed using a scanning electron microscope(SEM).The feasibility analysis was carried out by pulsed X-rays,slug-retrieval test and static penetration tests.The shaped charge jet forming and penetration law of inner tungsten-coated double-layer liner were studied by numerical simulation method.The results showed that the double-layer liners could form well-shaped jets.The errors between the X-ray test results and the numerical results were within 11.07%.A slug-retrieval test was found that the retrieved slug was similar to a numerically simulated slug.Compared with the traditional pure copper shaped charge jet,the penetration depth of the double-layer shaped charge liner increased by 11.4% and>10.8% respectively.In summary,the test results are good,and the numerical simulation is in good agreement with the test,which verified the feasibility of using the CVD method to fabricate double-layer charge liners with a high-density and high-strength refractory metal as the inner liner. 展开更多
关键词 Shaped charge Chemical vapor deposition TUNGSTEN double-layer charge liner X-ray PENETRATION
下载PDF
Discovery and Significance of the Triassic–Late Paleozoic Double-layered Basement in the Songliao Basin:Based on the Complete Coring Data from ICDP Borehole SK2
3
作者 YANG Zhuolong WANG Pujun +2 位作者 GAO Youfeng GAO Chuancheng TANG Xin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第S01期75-76,共2页
The Songliao Basin(SLB)covers an area of approximately 260,000 km2in northeastern Asia and preserves a continuous and complete Cretaceous terrestrial record(Wang et al.,2021).The region is the most important petrolife... The Songliao Basin(SLB)covers an area of approximately 260,000 km2in northeastern Asia and preserves a continuous and complete Cretaceous terrestrial record(Wang et al.,2021).The region is the most important petroliferous sedimentary basin in China because of its continual annual oil and gas equivalent production of tens of millions of tons(ca.220–440 million barrels per year)since 1959.The SLB was previously thought to have developed on Hercynian basement and accumulated continuous sedimentary deposits during the Late Jurassic and Cretaceous(Wan et al.,2013;Wang et al.,2016). 展开更多
关键词 double-layered basement ICDP Triassic and Paleozoic Songliao Basin
下载PDF
Performance and Application of Double-layered Microcapsule Corrosion Inhibitors
4
作者 余海燕 WANG Yingxiang +2 位作者 WANG Ruizhi HU Lintong WANG Tianlei 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第4期845-853,共9页
Double-layered microcapsule corrosion inhibitors were developed by sodium monofluorophosphate as the core material,polymethyl methacrylate as the inner wall material,and polyvinyl alcohol as the outer wall material co... Double-layered microcapsule corrosion inhibitors were developed by sodium monofluorophosphate as the core material,polymethyl methacrylate as the inner wall material,and polyvinyl alcohol as the outer wall material combining the solvent evaporation method and spray drying method.The protection by the outer capsule wall was used to prolong the service life of the corrosion inhibitor.The dispersion,encapsulation,thermal stability of microcapsules,and the degradation rate of capsule wall in concrete pore solution were analyzed by ultra-deep field microscopy,scanning electron microscopy,thermal analyzer,and sodium ion release rate analysis.The microcapsules were incorporated into mortar samples containing steel reinforcement,and the effects of double-layered microcapsule corrosion inhibitors on the performance of the cement matrix and the actual corrosion-inhibiting effect were analyzed.The experimental results show that the double-layered microcapsules have a moderate particle size and uniform distribution,and the capsules were completely wrapped.The microcapsules as a whole have good thermal stability below 230 ℃.The monolayer membrane structure microcapsules completely broke within 1 day in the simulated concrete pore solution,and the double-layer membrane structure prolonged the service life of the microcapsules to 80 days in the simulated concrete pore solution before the core material was completely released.The mortar samples containing steel reinforcement incorporated with the double-layered microcapsule corrosion inhibitors still maintained a higher corrosion potential than the monolayer microcapsule corrosion inhibitors control group at 60 days.The incorporation of double-layered microcapsules into the cement matrix has no significant adverse effect on the setting time and early strength. 展开更多
关键词 corrosion inhibitors MICROCAPSULE double-layer structure potentiodynamic polarization curve
下载PDF
Time-sequenced damage behavior of reactive projectile impacting double-layer plates
5
作者 Ying Yuan Yi-qiang Cai +3 位作者 Huan-guo Guo Peng-wan Chen Rui Liu Hai-fu Wang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第9期263-272,共10页
The time-sequenced damage behavior of the reactive projectile impacting double-layer plates is discussed.The analytical model considering the combined effect of kinetic and chemical energy is developed to reveal the d... The time-sequenced damage behavior of the reactive projectile impacting double-layer plates is discussed.The analytical model considering the combined effect of kinetic and chemical energy is developed to reveal the damage mechanism.The influences of impact velocity and reactive projectile chemical characteristics on the damage effect are decoupled analyzed based on this model.These analyses indicate that the high energy releasing efficiency and fast reaction propagation velocity of the reactive projectile are conducive to enhancing the damage effect.The experiments with various reactive projectiles impact velocity increasing from 702 to 1385 m/s were conducted to verify this model.The experimental results presented that,the damage hole radius of the rear-plate increases with the increase of impact velocity.At the impact velocity of 1350 m/s,the radius of damage hole formed by PTFE/Al/Bi_(2)O_(3),PTFE/Al/MoO_(3),PTFE/Al/Fe_(2)O_(3)projectile on the rear-plate become smaller in sequence.These results are consistent with the analytical model prediction,demonstrating that this model can predict the damage effect quantitatively.This work is of constructive significance to the application of reactive projectiles. 展开更多
关键词 Reactive projectile Damage behaviors Impact double-layer plates
下载PDF
Gas-and plasma-driven hydrogen permeation behavior of stagnant eutectic-solid GaInSn/Fe double-layer structure
6
作者 荆文娜 刘建星 +8 位作者 郭恒鑫 王思蜀 毕海林 陈波 陈建军 王宏彬 韦建军 叶宗标 芶富均 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第4期482-492,共11页
Gas-driven permeation(GDP)and plasma-driven permeation(PDP)of hydrogen gas through Ga In Sn/Fe are systematically investigated in this work.The permeation parameters of hydrogen through Ga In Sn/Fe,including diffusivi... Gas-driven permeation(GDP)and plasma-driven permeation(PDP)of hydrogen gas through Ga In Sn/Fe are systematically investigated in this work.The permeation parameters of hydrogen through Ga In Sn/Fe,including diffusivity,Sieverts'constant,permeability,and surface recombination coefficient are obtained.The permeation flux of hydrogen through Ga In Sn/Fe shows great dependence on external conditions such as temperature,hydrogen pressure,and thickness of liquid Ga In Sn.Furthermore,the hydrogen permeation behavior through Ga In Sn/Fe is well consistent with the multilayer permeation theory.In PDP and GDP experiments,hydrogen through Ga In Sn/Fe satisfies the diffusion-limited regime.In addition,the permeation flux of PDP is greater than that of GDP.The increase of hydrogen plasma density hardly causes the hydrogen PDP flux to change within the test scope of this work,which is due to the dissolution saturation.These findings provide guidance for a comprehensive and systematic understanding of hydrogen isotope recycling,permeation,and retention in plasma-facing components under actual conditions. 展开更多
关键词 liquid metals double-layer gas-driven permeation plasma-driven permeation
下载PDF
Preparation and Microwave Absorbing Properties of Double-layer Fine Iron Tailings Cementitious Materials
7
作者 LI Huawei WANG Rong +3 位作者 WANG Yulin LIU Feiyu WANG Qian WEI Muwang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第5期1126-1135,共10页
To develop the microwave absorbing(MA)properties of cementitious material mixed with mine solid waste,the iron tailings cementitious microwave absorbing materials were prepared.The iron tailings was treated into diffe... To develop the microwave absorbing(MA)properties of cementitious material mixed with mine solid waste,the iron tailings cementitious microwave absorbing materials were prepared.The iron tailings was treated into different particle sizes by planetary ball mill,and the physicochemical properties of iron tailings were tested by laser particle size analyzer and scanning electron microscope(SEM).The electromagnetic parameters of iron tailings cementitious materials were characterized by a vector network analyzer and simulated MA properties,and the MA properties of iron tailings-cement composite system with steel fiber as absorber was studied.Based on the design of the single-layer structure,optimum mix ratio and thickness configuration method of double-layer structure were further studied,meanwhile,the mechanical properties and engineering application were analyzed and discussed.The results show that the particle size of iron tailings can afiect its electromagnetic behavior in cementitious materials,and the smaller particles lead the increase of demagnetisation efiect induced by domain wall motion and achieve better microwave absorbing properties in cementitious materials.When the thickness of matching layer and absorbing layer is 5 mm,the optimized microwave absorbing properties of C1/C3 double-layer cementitious material can obtain optimal RL value of-27.61 dB and efiective absorbing bandwidth of 0.97 GHz,which attributes to the synergistic efiect of impedance matching and attenuation characteristics.The double-layer microwave absorbing materials obtain excellent absorbing properties and show great design flexibility and diversity,which can be used as a suitable candidate for the preparation of favorable microwave absorbing cementitious materials. 展开更多
关键词 microwave absorbing properties iron tailings electromagnetic parameters single-layer structure double-layer structure impedance matching
下载PDF
Empirical formulae for electric double-layer repulsion between two arbitrarily inclined clay particles 被引量:3
8
作者 Xiangyu Shang Juming Lu +2 位作者 Lianfei Kuang Chen Yang Guoqing Zhou 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2018年第6期1183-1189,共7页
To understand the mesoscopic mechanism of clayey soil in view of macroscopic behavior, it is essential to quantitatively calculate the electric double-layer repulsion between arbitrarily inclined clay particles.Howeve... To understand the mesoscopic mechanism of clayey soil in view of macroscopic behavior, it is essential to quantitatively calculate the electric double-layer repulsion between arbitrarily inclined clay particles.However, suitable calculation methods with high efficiency and accuracy are still rare at present in literature. Based on a great number of numerical calculations of the repulsion between two inclined platy clay particles, explicit empirical formulae for estimating electric double-layer repulsion between clay particles are put forward. Comparison between the empirical solutions and corresponding numerical results shows that the proposed formulae have a reasonable accuracy, and application of the presented formula is easy and efficient. 展开更多
关键词 Clay particles Electric double-layer repulsion Numerical analysis Empirical formula
下载PDF
Double-Layer-Optimizing Method of Hybrid Energy Storage Microgrid Based on Improved Grey Wolf Optimization
9
作者 Xianjing Zhong Xianbo Sun Yuhan Wu 《Computers, Materials & Continua》 SCIE EI 2023年第8期1599-1619,共21页
To reduce the comprehensive costs of the construction and operation of microgrids and to minimize the power fluctuations caused by randomness and intermittency in distributed generation,a double-layer optimizing confi... To reduce the comprehensive costs of the construction and operation of microgrids and to minimize the power fluctuations caused by randomness and intermittency in distributed generation,a double-layer optimizing configuration method of hybrid energy storage microgrid based on improved grey wolf optimization(IGWO)is proposed.Firstly,building a microgrid system containing a wind-solar power station and electric-hydrogen coupling hybrid energy storage system.Secondly,the minimum comprehensive cost of the construction and operation of the microgrid is taken as the outer objective function,and the minimum peak-to-valley of the microgrid’s daily output is taken as the inner objective function.By iterating through the outer and inner layers,the system improves operational stability while achieving economic configuration.Then,using the energy-self-smoothness of the microgrid as the evaluation index,a double-layer optimizing configuration method of the microgrid is constructed.Finally,to improve the disadvantages of grey wolf optimization(GWO),such as slow convergence in the later period and easy falling into local optima,by introducing the convergence factor nonlinear adjustment strategy and Cauchy mutation operator,an IGWO with excellent global performance is proposed.After testing with the typical test functions,the superiority of IGWO is verified.Next,using IGWO to solve the double-layer model.The case analysis shows that compared to GWO and particle swarm optimization(PSO),the IGWO reduced the comprehensive cost by 15.6%and 18.8%,respectively.Therefore,the proposed double-layer optimizationmethod of capacity configuration ofmicrogrid with wind-solar-hybrid energy storage based on IGWO could effectively improve the independence and stability of the microgrid and significantly reduce the comprehensive cost. 展开更多
关键词 Wind-solar microgrid hybrid energy storage optimization configuration double-layer optimization model IGWO
下载PDF
Experimental,Numerical,and Analytical Studies on the Bending of Mechanically Lined Pipe 被引量:1
10
作者 WEI Wen-bin YUAN Lin +1 位作者 ZHOU Jia-sheng LIU Zheng 《China Ocean Engineering》 SCIE EI CSCD 2024年第2期221-232,共12页
Mechanically lined pipe(MLP)is often used for offshore oil and gas transport because of its low cost and corrosion resistance.During installation and operation,the pipe may undergo severe bending deformation,which cau... Mechanically lined pipe(MLP)is often used for offshore oil and gas transport because of its low cost and corrosion resistance.During installation and operation,the pipe may undergo severe bending deformation,which causes the liner to separate from the outer pipe and buckles,affecting the stability of the whole line.In this paper,the buckling response of MLP subjected to bending is investigated to clarify its bending characteristics by employing both experiments,numerical simulation,as theoretical methods.Two types of MLPs were manufactured with GB 45 carbon steel(SLP)and Al 6061(ALP)used as the outer pipe material,respectively.The hydraulic expansion and bending experiments of small-scale MLPs are conducted.In addition to the ovalized shape of the cross-section for the SLP specimens,the copper liner was found to wrinkle on the compressive side.In contrast,the liner of ALP remains intact without developing any wrinkling and collapse mode.In addition,a dedicated numerical framework and theoretical models were also established.It was found both the manufacturing and bending responses of the MLP can be well reproduced,and the predicted maximum moment and critical curvatures are in good agreement with the experimental results. 展开更多
关键词 lined pipe BENDING nonlinear ring theory BUCKLING PLASTICITY
下载PDF
Microwave absorption properties of a double-layer absorber based on nanocomposite BaFe_(12)O_(19)/α-Fe and nanocrystalline α-Fe microfibers 被引量:1
11
作者 沈湘黔 刘洪波 +3 位作者 王舟 钱昕晔 景茂祥 杨新春 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第7期738-743,共6页
The nanocomposite BaFe12O19/α-Fe and nanocrystalline α-Fe microfibers with diameters of 1-5 μm, high aspect ratios and large specific areas are prepared by the citrate gel transformation and reduction process. The ... The nanocomposite BaFe12O19/α-Fe and nanocrystalline α-Fe microfibers with diameters of 1-5 μm, high aspect ratios and large specific areas are prepared by the citrate gel transformation and reduction process. The nanocomposite BaFe12O19/α-Fe microfibers show some exchange-coupling interactions largely arising from the magnetization hard (BaFe12019) and soft (a-Fe) nanoparticles. For the microwave absorptions, the double-layer structures consisting of the nanocomposite BaFe12O19/α-Fe and α-Fe microfibers each exhibit a wide band and strong absorption behavior. When the nanocomposite BaFel2O19/α-Fe microfibers are used as a matching layer of 2.3 mm in thickness and a-Fe microfibers as an absorbing layer of 1.2 mm in thickness, the optimal reflection loss (RL) achieves -47 dB at 15.6 GHz, the absorption bandwidth is about 12.7 GHz ranging from 5.3 to 18 GHz, exceeding -20 dB, which covers 72.5% C-band (4.2-8.2 GHz) and whole X-band (8.2-12.4 GHz) and Ku-band (12.4-18 GHz). The enhanced absorption properties of these double-layer absorbers are mainly ascribed to the improvement in impedance matching ability and microwave multi-reflection largely resulting from the dipolar polarization, interfacial polarization, exchange-coupling interaction, and small size effect. 展开更多
关键词 BAFE12O19 Α-FE MICROFIBER double-layer absorber
下载PDF
Double-layer microwave absorber of nanocrystalline strontium ferrite and iron microfibers 被引量:1
12
作者 Wei Chun-Yu Shen Xiang-Qian Song Fu-Zhan 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第2期541-547,共7页
Microwave absorption properties of the nanocrystalline strontium ferrite (SrFe12O19) and iron (α-Fe) microfibers for single-layer and double-layer structures are investigated in a frequency range of 2 GHz 18 GHz.... Microwave absorption properties of the nanocrystalline strontium ferrite (SrFe12O19) and iron (α-Fe) microfibers for single-layer and double-layer structures are investigated in a frequency range of 2 GHz 18 GHz. For the singlelayer absorbers, the nanocrystalline SrFe12O19 microfibers show some microwave absorptions at 6 GHz 18 GHz, with a minimum reflection loss (RL) value of -11.9 dB at 14.1 GHz for a specimen thickness of 3.0 mm, while for the nanocrystalline α-Fe microfibers, their absorptions largely take place at 15 GHz-18 GHz with the RL value exceeding -10 dB, with a minimum .RL value of about -24 dB at 17.5 GHz for a specimen thickness of 0.7 mm. For the doublelayer absorber with an absorbing layer of α-Fe microfibers with a thickness of 0.7 mm and matching layer of SrFe12O19 microfibers with a thickness of 1.3 ram, the minimum RL value is about -63 dB at 16.4 GHz and the absorption band width is about 6.7 GHz ranging from 11.3 GHz to 18 GHz with the RL value exceeding -10 dB which covers the whole Ku-band (12.4 GHz 18 GHz) and 27% of X-band (8.2 GHz 12.4 GHz). 展开更多
关键词 nanocrystalline microfibers microwave absorber double-layer structure
下载PDF
Canine Myofascial Kinetic Lines: A Descriptive Dissection Study Including Related Function and Locomotion and Comparison of the Human and Equine Myofascial Kinetic Lines
13
作者 Vibeke S. Elbrønd 《Open Journal of Veterinary Medicine》 CAS 2024年第9期229-256,共28页
Aim: This dissection study was conducted to verify if the Myofascial kinetic lines, outlined in detail in humans and recently documented in horses, were present in dogs. These dynamic lines present rows of interconnec... Aim: This dissection study was conducted to verify if the Myofascial kinetic lines, outlined in detail in humans and recently documented in horses, were present in dogs. These dynamic lines present rows of interconnected muscles, myofascia and other fascia structures, which influence the biomechanics of the spine and limbs. Methods: Forty-two dogs of different breeds and genders were dissected, imaged, and videoed. Results: Similar kinetic lines were verified in the dog, as described in humans and horses, and additionally, three new branches of the lines were discovered. The kinetic lines described were three superficial lines: Dorsal, Ventral, and Lateral, which all started in the hindlimb and ended in the temporal and occipital regions. These lines act respectively in spinal extension, flexion, and lateral flexion. Three profound lines, which started in the tail and ended in the head. The Deep Dorsal Line followed the transversospinal myofascia. The Deep Ventral Line showed an additional start deep in the medial hind limb, continued in the hypaxial myofascia, and enveloped all the viscera. Also, the Deep Lateral Line started in the hindlimb but parted along the trunk in the deep lateral myofascial structures. Two helical lines crossed the midline two or three times and served to rotate the spine. The Functional Line established a sling from the axilla to the contralateral stifle and presented a new ipsilateral branch. The Spiral Line connected the head and the ipsilateral tarsus and additionally presented a new straight branch. The four front limb lines describe their motion: the Front Limb Protraction and Retraction, Adduction, and Abduction Lines. Conclusion: The canine lines mirrored the equine and human lines with exceptions due to differences in anatomy, foot posture, lumbosacral flexibility, and their biomechanical constitution as predator versus prey animals. Additionally, three new canine branches were verified and described. 展开更多
关键词 Myofascial Kinetic Lines Canis Familiaris Superficial Lines Deep Lines Locomotive Connections Viscero-Somatic Connections
下载PDF
Flood Risk Mapping of the Benin Municipalities at the Intersection of the Coastal Sedimentary Zone and the Crystalline Surface
14
作者 Éric Alain Mahugnon Tchibozo Apollinaire Cyriaque Agbon +1 位作者 Azize Ognondoun Bidossessi Roméo David Houessinon 《Journal of Geographic Information System》 2024年第5期321-342,共22页
Climate change and population growth have led to the increase and/or intensification of flooding becoming a major issue. The objective of this study is to visualize flooding risk of municipalities at the intersection ... Climate change and population growth have led to the increase and/or intensification of flooding becoming a major issue. The objective of this study is to visualize flooding risk of municipalities at the intersection of the coastal sedimentary zone and the crystalline surface. The methodology adopted is based on geomatic approach, which involves documentary research, processing and assisted classification using remote sensing images and multi-criteria analysis of the Geographic Information System (GIS). Flooding risk is very high at 8.85% in Djidja, Toffo, Zè and Bonou municipalities. In other municipalities such as Agbangnizoun, Abomey, Bohicon, Za-Kpota and Cove, it is high of 46.85%. To the Southeast of the study area, it is located on the eastern and western banks of Oueme Valley. The medium risk represents 26.35% and is located in the municipalities of Ouinhi and Adjohoun. The other municipalities have a low rate of 17.95%. Risk modeling has made it possible to access the various levels of rising water that can cause flooding. Land-use planning decisions can be influenced by the results of this study. 展开更多
关键词 Geomatic Flood Risk Contact Line Municipalities BENIN
下载PDF
Toward a Direct Measurement of the Cosmic Acceleration:The Pilot Observation of HI 21 cm Absorption Line at FAST
15
作者 Jiangang Kang Chang-Zhi Lu +1 位作者 Tong-Jie Zhang Ming Zhu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第7期47-55,共9页
This study presents results on detecting neutral atomic hydrogen(H I)21 cm absorption in the spectrum of PKS PKS1413+13 at redshift z=0.24670041.The observation was conducted by FAST,with a spectral resolution of10 Hz... This study presents results on detecting neutral atomic hydrogen(H I)21 cm absorption in the spectrum of PKS PKS1413+13 at redshift z=0.24670041.The observation was conducted by FAST,with a spectral resolution of10 Hz,using 10 minutes of observing time.The global spectral profile is examined by modeling the absorption line using a single Gaussian function with a resolution of 10 kHz within a 2 MHz bandwidth.The goal is to determine the rate of the latest cosmic acceleration by directly measuring the redshift evolution of the H I 21 cm absorption line with Hubble flow toward a common background quasar over a decade or longer time span.This will serve as a detectable signal generated by the accelerated expansion of the Universe at redshift z<1,referred to as redshift drift z(5)or the SL effect.The measured H I gas column density in this DLA system is approximately equivalent to the initial observation value,considering uncertainties of the spin temperature of a spiral host galaxy.The high signal-to-noise ratio of 57,obtained at a 10 kHz resolution,strongly supports the feasibility of using the H I 21 cm absorption line in DLA systems to accurately measure the redshift drift rate at a precision level of around 10~(-10)per decade. 展开更多
关键词 (cosmology)cosmological parameters-cosmology observations-cosmology theory-(cosmology)dark energy-radio lines ISM-radio lines galaxies-ISM clouds
下载PDF
Derivative Spectroscopy and its Application at Detecting the Weak Emission/Absorption Lines
16
作者 Lihuan Yu Jiangdan Li +4 位作者 Jinliang Wang Jiajia Li Jiao Li Qiang Xi Zhanwen Han 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第3期205-223,共19页
The development of spectroscopic survey telescopes like Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST),Apache Point Observatory Galactic Evolution Experiment and Sloan Digital Sky Survey has opened ... The development of spectroscopic survey telescopes like Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST),Apache Point Observatory Galactic Evolution Experiment and Sloan Digital Sky Survey has opened up unprecedented opportunities for stellar classification.Specific types of stars,such as early-type emission-line stars and those with stellar winds,can be distinguished by the profiles of their spectral lines.In this paper,we introduce a method based on derivative spectroscopy(DS)designed to detect signals within complex backgrounds and provide a preliminary estimation of curve profiles.This method exhibits a unique advantage in identifying weak signals and unusual spectral line profiles when compared to other popular line detection methods.We validated our approach using synthesis spectra,demonstrating that DS can detect emission signals three times fainter than Gaussian fitting.Furthermore,we applied our method to 579,680 co-added spectra from LAMOST Medium-Resolution Spectroscopic Survey,identifying 16,629 spectra with emission peaks around the Hαline from 10,963 stars.These spectra were classified into three distinct morphological groups,resulting in nine subclasses as follows.(1)Emission peak above the pseudo-continuum line(single peak,double peaks,emission peak situated within an absorption line,P Cygni profile,Inverse P Cygni profile);(2)Emission peak below the pseudo-continuum line(sharp emission peak,double absorption peaks,emission peak shifted to one side of the absorption line);(3)Emission peak between the pseudo-continuum line. 展开更多
关键词 LINE identification-line profiles-methods data analysis-techniques spectroscopic-techniques radial velocities
下载PDF
Petrology of Spinel-Lherzolite Xenoliths from Mazéléand Others Northen Xenoliths Localities of Cameroon Volcanic Line: Exchange Reactions and Equilibrium State
17
作者 Nguihdama Dagwai Kamgang Pierre +2 位作者 Mbowou Gbambié Isaac Bertrand Chazot Gilles Ngounouno Ismaïla 《Open Journal of Geology》 CAS 2024年第5期629-653,共25页
The alkaline volcanism of the Cameroon Volcanic Line in its northern domain has raised many fresh enclaves of peridotites. The samples selected come from five (05) different localities (Liri, in the plateau of Kapsiki... The alkaline volcanism of the Cameroon Volcanic Line in its northern domain has raised many fresh enclaves of peridotites. The samples selected come from five (05) different localities (Liri, in the plateau of Kapsiki, Mazélé in the NE of Ngaoundéré, Tello and Ganguiré in the SE of Ngaoundéré and Likok, locality located in the west of Ngaoundé). The peridotite enclaves of the above localities show restricted mineralogical variation. Most are four-phase spinel-lherzolites, indicating that this is the main lithology that forms the lithospheric mantle below the shallow zone. No traces of garnet or primary plagioclase were detected, which strongly limits the depth range from which the rock fragments were sampled. The textures and the wide equilibrium temperatures (884˚C - 1115˚C) indicate also entrainment of lherzolite xenoliths from shallow depths within the lithosphere and the presence of mantle diapirism. The exchange reactions and equilibrium state established in this work make it possible to characterize the chemical composition of the upper mantle of each region and test the equilibrium state of the phases between them. Variations of major oxides and incompatible elemental concentrations in clinopyroxene indicate a primary control by partial melting. The absence of typical “metasomatic” minerals, low equilibration temperatures and enriched LREE patterns indicate that the upper mantle below septentrional crust of Cameroun underwent an event of cryptic metasomatic enrichment prior to partial melting. The distinctive chemical features, LREE enrichment, strong U, Ce and Pr, depletion relative to Ba, Nb, La, Pb, and T, fractionation of Zr and Hf and therefore ligh high Zr/Hf ratio, low La/Yb, Nb/La and Ti/Eu are all results of interaction of refractory peridotite residues with carbonatite melts. 展开更多
关键词 XENOLITHS Upper Mantle Northern Region Adamawa Cameroon Volcanic Line Exchange Reaction
下载PDF
Evaluation of red soil-bentonite mixtures for compacted clay liners
18
作者 A.S.Devapriya T.Thyagaraj 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第2期697-710,共14页
Compacted clay liners are an integral part of the waste landfills,which are provided to contain the leachate within the landfills and protect the surrounding environment.Generally,locally available natural soils are u... Compacted clay liners are an integral part of the waste landfills,which are provided to contain the leachate within the landfills and protect the surrounding environment.Generally,locally available natural soils are used for the construction of compacted clay liners if they satisfy the design criteria.However,not all soils in their natural state satisfy all the design criteria for the liner materials.Thus,there is a definite need to modify the locally available natural soils by blending with bentonite to meet the required design criteria for the liners.In view of this,the present study evaluates the suitability of an Indian red soil enhanced with bentonite as a liner material.To achieve this,a series of experiments were carried out using locally available red soil and bentonite.First,the suitability of the red soil was evaluated as a liner material.The experimental results showed that the red soil met all the selection criteria stipulated by the Environmental Protection Agencies(EPAs)for the liners except the hydraulic conductivity criterion.Therefore,the red soil was mixed with bentonite contents of 10%,20%and 30%,and the red soil-bentonite mixtures were evaluated for their suitability for liners in their compacted state.Further,as the liners in the arid and semi-arid regions are subjected to moisture variations due to seasonal moisture fluctuations and other factors,the red soil-bentonite mixtures were subjected to wetdry cycles,and their suitability was evaluated after wet-dry cycles.The experimental results revealed that all the red soil-bentonite mixtures met the stipulated EPA criteria for the liners in the as-compacted state.However,the red soil-bentonite mixtures with 20%and 30%bentonite contents only satisfied the hydraulic conductivity requirement even after wet-dry cycles.The experimental findings were supplemented with the microstructural insights captured through digital camera images,scanning electron microscopy(SEM),and mercury intrusion porosimetry(MIP)studies. 展开更多
关键词 Compacted clay lines Hydraulic conductivity Wet-dry cycles Microstructure
下载PDF
Establishment and characterization of a canine chondrosarcoma cell line:Mango
19
作者 Meilin Wang Xiao Wang +8 位作者 Lixin He Hongbo Gao Wenxuan Li Huili Feng Qingyuan Zhao Wenwen Zhang Chengzong Li Bohan Zhang Changwei Qiu 《Animal Diseases》 CAS 2024年第3期186-197,共12页
In the global progress of bone tumor research,established stable and long-lasting transgenic chondrosarcoma(CSA)cell lines are rare,mainly of murine and human origin,while the establishment of canine CSA cell lines ha... In the global progress of bone tumor research,established stable and long-lasting transgenic chondrosarcoma(CSA)cell lines are rare,mainly of murine and human origin,while the establishment of canine CSA cell lines has yet to be reported.This study established a canine CSA cell line to facilitate the basic clinical study of canine CSA.Fifty fve cases of canine osteolytic disease were collected,and more than 10 bone tumor samples from dogs with typical clinical signs were used for primary cell culture.A cell line with stable passaging for more than 100 generations and mouse tumorigenic ability was successfully cultured.According to the clinical characteristics of the dog and the histopathological results of the primary tumor,CSA was diagnosed,and the CSA cell line was designated Mango.Immunohistochemical(IHC)results showed that the immunoreactivity of bone gamma-carboxyglutamate protein(BGLAP),secreted protein acidic and rich in cysteine(SPARC),alkaline phosphatase(ALPL),vimentin(VIM)and S100 were positive.However,the immunoreactivity of pan-cytokeratin(PCK),chromogranin A(CGA),and platelet endothelial cell adhesion molecule-1(CD31)was negative.Immunofuorescence(IF)results showed that the protein expressions in the Mango cell line were consistent with the IHC identifcation of the primary tumor.The Mango cell line’s doubling time was 43.92 h,and the cell formation rate exceeded 20%.There were abnormal chromosome numbers,hetero staining with toluidine blue,and certain calcifcation abilities.It could be passaged stably and continuously without changing the cell morphology and characteristics.In vivo,the cells were successfully injected into the nude mice model with a tumorigenic rate of 100%.The immunophenotype of the xenograft tumor was consistent with that of the primary tumor.Therefore,we efectively established a canine CSA cell line.As a promising cell material,this cell line can be used to construct a tumor-bearing model conducive to the subsequent basic research of canine CSA.Moreover,because of its similarity to human CSA,the animal model of CSA is also indispensable for investigating human CSA. 展开更多
关键词 Canine chondrosarcoma Cell line ESTABLISHMENT CHARACTERIZATION Tumorigenicity
下载PDF
Characterization of the infectivity of an Indonesian Zika virus strain in mammalian cell lines
20
作者 Justus Thomas Obiajulu Sievers Anom Bowolaksono R.Tedjo Sasmono 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2024年第5期215-224,共10页
Objective:To characterize the infection patterns and growth characteristics of the Zika virus(ZIKV)strain JMB-185 from Indonesia in various mammalian cell lines.Methods:ZIKV was grown in human(A549,HEK293,HepG2,Huh7,J... Objective:To characterize the infection patterns and growth characteristics of the Zika virus(ZIKV)strain JMB-185 from Indonesia in various mammalian cell lines.Methods:ZIKV was grown in human(A549,HEK293,HepG2,Huh7,Jurkat,and THP-1)and non-human mammalian(RAW264.7,Vero,and Vero76)cell lines.Viral replication kinetics were measured using plaque assay,while intra-and extracellular viral RNA concentrations were assessed using RT-PCR.Flow cytometry was used to quantify the infected cells and cell viability was measured using an MTT assay.The ability of ZIKV to infect cell lines was visualized using a fluorescence immunostaining assay.Results:This ZIKV strain preferentially infected the lung,kidney,and liver cell lines A549,HEK293,Huh7,Vero,and Vero76,but not the immune cells Jurkat,RAW264.7,and THP-1.By contrast,the ZIKV showed no sign of infection in HepG2 cells,while maintaining viral titer over 3 days post-infection,with no infection recorded in immunostaining,no increase in viral RNA,and no indication of cell deterioration.Conclusions:The Indonesian ZIKV strain has a similar infection profile as other strains,except for its poor infectivity on HepG2 cells.Information on the growth characteristics of Indonesia ZIKV will help expand our understanding of the biology of ZIKV which will be useful for various applications including antiviral discovery. 展开更多
关键词 Zika virus Infectivity REPLICATION Cell lines In vitro
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部