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Study on Coaxiality Measurement System of Compound Gear Shaft Based on Non⁃contact Optic 被引量:3
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作者 YE Zhibin LU Yonghua +2 位作者 TAN Jie LI Yanlong CHAI Zhong 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2021年第3期393-403,共11页
Aiming at the shortcomings of traditional contact measurement methods such as low measurement efficiency,high cost and low accuracy,a non-contact optical measurement method based on the laser displacement sensor is pr... Aiming at the shortcomings of traditional contact measurement methods such as low measurement efficiency,high cost and low accuracy,a non-contact optical measurement method based on the laser displacement sensor is proposed.According to the relevant regulations of the coaxiality error evaluation standard and the structural characteristics of the compound gear shaft,we have designed and built a set of supporting software system as well as a hardware test platform.In this paper,the distance difference threshold and scale threshold methods are used to eliminate outlier data.The least squares circle is selected to calculate the center of the circle and the minimum containment cylinder axis method is used as the reference axis of the composite gear shaft.Compensated by the standard step shaft calibration,the coaxiality error of the composite gear shaft can be measured to be within 0.01 mm in less than two minutes.The range value of the multi-section measurement test is 0.065 mm.The average coaxiality error is∅0.476 mm. 展开更多
关键词 compound gear shaft non-contact measurement laser displacement sensor coaxiality measuring system
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Experimental and numerical study of physics field and energy transfer in laser enhanced plasma arc
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作者 Fan Jiang Hanbin Ren +5 位作者 Bin Xu Wenlong Li Guokai Zhang Yongquan Han Guowei Li Zhenbang Sun 《China Welding》 2026年第1期92-107,共16页
To improve the penetration of thick plates,a laser-enhanced plasma arc welding process was developed.However,the current understanding of laser absorption and energy transfer mechanisms is still unclear,limiting its o... To improve the penetration of thick plates,a laser-enhanced plasma arc welding process was developed.However,the current understanding of laser absorption and energy transfer mechanisms is still unclear,limiting its optimization and application.This work establishes mathematical model of this novel heat source including electron density based on the gas state equation,Saha equation,and charge conservation equation.This model reveals the laser transmission characteristics in the plasma controlled by temperature and electron density,as well as the electrical and thermal transfer from the composite arc to the base material.The simulated temperature fields,arc pressure distributions,and arc voltages showed good agreement with experimental measurements,with peak pressure errors within 50 Pa and voltage differences within 0.3 V,validating the accuracy of the model.The results showed that the laser increased the arc temperature inside the keyhole,extending the high-temperature zone downwards.The laser has altered the current density distribution at the keyhole edge,decreasing the upper part but increasing the lower part.The trend of heat flux density change is consistent with the current density.There is a high laser absorption zone in the arc between the tungsten electrode and base metal,whose position changes with laser power,thereby improving the position and axial energy distribution of the plasma arc. 展开更多
关键词 Coaxial composite High electron density High absorption area Heat flux difference Keyhole boundary
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Determining the Energy Potential of Deep Borehole Heat Exchangers in Croatia and Economic Analysis of Oil&Gas Well Revitalization
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作者 Marija Macenic Tomislav Kurevija Tin Herbst 《Energy Engineering》 2026年第1期1-26,共26页
The increased interest in geothermal energy is evident,along with the exploitation of traditional hydrothermal systems,in the growing research and projects developing around the reuse of already-drilled oil,gas,and ex... The increased interest in geothermal energy is evident,along with the exploitation of traditional hydrothermal systems,in the growing research and projects developing around the reuse of already-drilled oil,gas,and exploration wells.The Republic of Croatia has around 4000 wells,however,due to a long period since most of these wells were drilled and completed,there is uncertainty about how many are available for retrofitting as deep-borehole heat exchangers.Nevertheless,as hydrocarbon production decreases,it is expected that the number of wells available for the revitalization and exploitation of geothermal energy will increase.The revitalization of wells via deep-borehole heat exchangers involves installing a coaxial heat exchanger and circulating the working fluid in a closed system,during which heat is transferred from the surrounding rock medium to the circulating fluid.Since drilled wells are not of uniformdepth and are located in areas with different thermal rock properties and geothermal gradients,an analysis was conducted to determine available thermal energy as a function of well depth,geothermal gradient,and circulating fluid flow rate.Additionally,an economic analysis was performed to determine the benefits of retrofitting existing assets,such as drilled wells,compared to drilling new wells to obtain the same amount of thermal energy. 展开更多
关键词 Geothermal energy deep coaxial borehole heat exchangers deep BHE heat extraction abandoned wells retrofitted wells
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Longitudinal combustion instability in a hypergolic liquid bipropellant combustor with single dual-swirl coaxial injector 被引量:1
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作者 Wei CHU Kangkang GUO +3 位作者 Yiheng TONG Yongjie REN Boqi XU Wansheng NIE 《Chinese Journal of Aeronautics》 2025年第3期280-291,共12页
Self-excited longitudinal combustion instabilities were investigated in a hypergolic liquid bipropellant combustor, which applied single dual-swirl coaxial injector. Hot-fire tests were conducted for four different in... Self-excited longitudinal combustion instabilities were investigated in a hypergolic liquid bipropellant combustor, which applied single dual-swirl coaxial injector. Hot-fire tests were conducted for four different injector geometries, while extensive tests on injection conditions were carried out for each injector geometry. The synchronous measurement of the pressure and heat release rate was applied, successfully capturing the process of the pressure and heat release rate enhanced coupling and developing into in-phase oscillation. By calculating Rayleigh index at the head and middle section of the chamber, it is shown that Rayleigh index of the middle section is even higher than that of the head, indicating a long heat release zone. When the combustion instability occurs, the pressure in propellant manifolds also oscillates with the same frequency and lags behind the oscillation in the combustor. Compared to the oscillation in the outer injector manifold, the oscillation in the inner injector manifold shows a higher correlation with that in the chamber in amplitude and phase. Based on numerical simulations of the multiphase cold flow inside the injector and combustion process in the chamber, it is found that injector geometries affect longitudinal combustion instability by changing spray cone angle. The spray with small cone angle is more sensitive to the modulation of longitudinal pressure wave in combustion simulations, which is more likely to excite the longitudinal combustion instability. Meanwhile, the combustion instability may be related to the pulsating coherent structure generated by the spray fluctuation, which is determined by injection conditions. Besides, a positive feedback closed-loop system associated with the active fluctuation and passive oscillation of the spray is believed to excite and sustain the longitudinal combustion instability. 展开更多
关键词 Longitudinal combustion instability Dual-swirl coaxial injector Unsymmetrical Dimethylhydrazine/Nitrogen Tetroxide(UDMH/NTO) Photomultiplier Tubes(PMT) Spray fluctuation Pressure wave Modulation
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Alignment-optimised coaxial visible-NIR-II dual-channel surgical navigation system and its clinical application in blood-supply assessment
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作者 ZHANG Yu-Huang LIU Xiao-Long +3 位作者 SUN Si-Ying FAN Xiao-Xiao LIN Hui QIAN Jun 《红外与毫米波学报》 北大核心 2025年第5期663-670,共8页
Fluorescence imaging in the second near-infrared window(NIR-II,900-1880 nm)offers high signalto-background ratio(SBR),enhanced definition,and superior tissue penetration,making it ideal for real-time surgical navigati... Fluorescence imaging in the second near-infrared window(NIR-II,900-1880 nm)offers high signalto-background ratio(SBR),enhanced definition,and superior tissue penetration,making it ideal for real-time surgical navigation.However,with single-channel imaging,surgeons must frequently switch between the surgi⁃cal field and the NIR-II images on the monitor.To address this,a coaxial dual-channel imaging system that com⁃bines visible light and 1100 nm longpass(1100LP)fluorescence was developed.The system features a custom⁃ized coaxial dual-channel lens with optimized distortion,achieving precise alignment with an error of less than±0.15 mm.Additionally,the shared focusing mechanism simplifies operation.Using FDA-approved indocya⁃nine green(ICG),the system was successfully applied in dual-channel guided rat lymph node excision,and blood supply assessment of reconstructed human flap.This approach enhances surgical precision,improves opera⁃tional efficiency,and provides a valuable reference for further clinical translation of NIR-II fluorescence imaging. 展开更多
关键词 NIR-II DUAL-CHANNEL fluorescence imaging surgical navigation COAXIAL
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Vibration evaluation and optimization of coaxial high-speed helicopter main transmission system and its experimental verification
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作者 Xiangying HOU Linyue QIU +6 位作者 Zhen QIN Yankun YANG Chenfei MA Sungki LYU Zhengminqing LI Guanghu JIN Rupeng ZHU 《Chinese Journal of Aeronautics》 2025年第9期208-224,共17页
To reduce the vibration of the Coaxial Helicopter Main Transmission System(CHMTS)considering both level and vertical flight conditions,a vibration evaluation and optimization model for the CHMTS was built.The vibratio... To reduce the vibration of the Coaxial Helicopter Main Transmission System(CHMTS)considering both level and vertical flight conditions,a vibration evaluation and optimization model for the CHMTS was built.The vibration simulation model of the CHMTS was set up by gear dynamics theory and loaded contact analysis.For better evaluation of the system vibration,a vibration evaluation method for the CHMTS was established by the G1 method-variation coefficient method.A hybrid Gravitational Search Algorithm-Simulated Annealing(GSA-SA)algorithm was combined to balance convergence speed and searching accuracy.The principle test was conducted to prove the accuracy of theoretical method,in which the maximum relative error is16.26%.The optional results show that the vibration of the optimized transmission system decreases significantly,in which the maximum reduction of key vibration indicators reaches more than 20%.The theoretical results have been compared to the experiment to verify the effectiveness of the vibration optimization method.The proposed method could be extended to other fields. 展开更多
关键词 Coaxial helicopter Gear dynamics Hybrid algorithm Transmission system Vibration optimization
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Scalable topological-entanglement conductive coaxial fibers with superior durability for wearable strain sensing and triboelectric fabric
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作者 Yulong Wang Xia Liu +7 位作者 Chengyu Li Wei Wang Di Guo Mengmeng Jia Shidai Tian Lingyu Wan Aifang Yu Junyi Zhai 《Journal of Materials Science & Technology》 2025年第30期154-165,共12页
Although flexible,stretchable,and conductive core-sheath structured smart fibers have propelled to the forefront research in wearable strain sensors and self-powered electronics,challenges related to scalability,compl... Although flexible,stretchable,and conductive core-sheath structured smart fibers have propelled to the forefront research in wearable strain sensors and self-powered electronics,challenges related to scalability,complexity,and mechanical durability remain.In this study,we propose a strategy for the scalable production of conductive coaxial fiber(CCF)with superior durability through one-step direct wet spinning coherent solutions.By introducing the polystyrene-block-polyisoprene-block-polystyrene phase in both inner and outer layers,CCFs feature an interleaved topology and share a similar modulus,successfully resolving the issue of layer separation over time.They can endure up to 15,000 cycles with no damage at a strain of 100%.In addition,the topological entanglement CCF as a strain sensor exhibits a broad operational range of up to 398.3%strain,outstanding sensitivity(i.e.,gauge factor=6713 at 398.3%strain)and swift response time(248 ms).Enhanced by machine learning,the system achieves a high accuracy rate of 95%in gait recognition and 100%in American Sign Language identification.Furthermore,the CCF can function as a wearable triboelectric nanogenerator(TENG)for self-powered sensing and mechanical energy harvesting.This study represents a significant step toward the development of multifunctional micro-wearable electronic devices,which hold immense promise for medical sensing and energy harvesting in smart wearable electronics,human-computer interaction,and artificial intelligence. 展开更多
关键词 Conductive coaxial fiber Topological-entanglement Strain sensor Triboelectric nanogenerator Self-powered sensor
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Coaxial method to investigate broadband dielectric properties of rocks over the 5 Hz to 3 GHz frequency range
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作者 Thierry Bore Yu-Jen Shen +5 位作者 Mehdi Serati Yoann Pascal Muhannad Al Kalbani Alexander Scheuermann Norman Wagner Markus Loewer 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第11期6837-6852,共16页
In this paper,we present a novel approach to study the electrical properties of intact rock by combining impedance and vector network analyzer measurements in the frequency range from 5 Hz to 3 GHz.For the firsttime,t... In this paper,we present a novel approach to study the electrical properties of intact rock by combining impedance and vector network analyzer measurements in the frequency range from 5 Hz to 3 GHz.For the firsttime,this study enables electrical characterization of the exact same rock sample over nine orders of magnitude in frequency range,utilizing a coaxial cell apparatus with specificallyprepared rock samples.Three types of rocks(basalt,sandstone and granite)with low to intermediate porosity(12.24%,16.9%and 7.49%,respectively)were characterized at varying saturation levels.The relaxation behavior of the samples was quantifiedusing an advanced phenomenological model incorporating both the dielectric constant and electrical conductivity in the form of Debye and Cole-Cole representations.Across the frequency range,three distinct relaxation processes were identified:a high-frequency water process and two interfacial processes related to interactions between the aqueous pore solution and mineral particles(membrane relaxation and Maxwell-Wagner effects).Additionally,an apparent direct current conductivity was observed.This comprehensive broadband analysis represents a further step toward the in situ characterization of rocks using electromagnetic fieldmeasurement methods and demonstrates advancements in both methodology and understanding of rock properties compared to existing studies. 展开更多
关键词 Dielectric spectroscopy ROCKS Coaxial transmission line Complex permittivity Complex conductivity
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Physics-Informed Gaussian Process Regression with Bayesian Optimization for Laser Welding Quality Control in Coaxial Laser Diodes
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作者 Ziyang Wang Lian Duan +2 位作者 Lei Kuang Haibo Zhou Ji’an Duan 《Computers, Materials & Continua》 2025年第8期2587-2604,共18页
The packaging quality of coaxial laser diodes(CLDs)plays a pivotal role in determining their optical performance and long-term reliability.As the core packaging process,high-precision laser welding requires precise co... The packaging quality of coaxial laser diodes(CLDs)plays a pivotal role in determining their optical performance and long-term reliability.As the core packaging process,high-precision laser welding requires precise control of process parameters to suppress optical power loss.However,the complex nonlinear relationship between welding parameters and optical power loss renders traditional trial-and-error methods inefficient and imprecise.To address this challenge,a physics-informed(PI)and data-driven collaboration approach for welding parameter optimization is proposed.First,thermal-fluid-solid coupling finite element method(FEM)was employed to quantify the sensitivity of welding parameters to physical characteristics,including residual stress.This analysis facilitated the identification of critical factors contributing to optical power loss.Subsequently,a Gaussian process regression(GPR)model incorporating finite element simulation prior knowledge was constructed based on the selected features.By introducing physics-informed kernel(PIK)functions,stress distribution patterns were embedded into the prediction model,achieving high-precision optical power loss prediction.Finally,a Bayesian optimization(BO)algorithm with an adaptive sampling strategy was implemented for efficient parameter space exploration.Experimental results demonstrate that the proposedmethod effectively establishes explicit physical correlations between welding parameters and optical power loss.The optimized welding parameters reduced optical power loss by 34.1%,providing theoretical guidance and technical support for reliable CLD packaging. 展开更多
关键词 Coaxial laser diodes laser welding physics-informed Gaussian process regression Bayesian optimization
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Application of a high-speed imaging system for characterization of a hypersonic plasma jet
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作者 Changjun LI Qingqing SHU +2 位作者 Zhiqiang CUI Guangyu LI Yong Chia Francis THIO 《Plasma Science and Technology》 2025年第5期94-102,共9页
Plasma-jet-driven magneto-inertial fusion(PJMIF),achieving uniform high-Z plasma liners via hypersonic plasma jets(Ma>10),requires precise control of jet reproducibility,synchronization,and mass/velocity uniformity... Plasma-jet-driven magneto-inertial fusion(PJMIF),achieving uniform high-Z plasma liners via hypersonic plasma jets(Ma>10),requires precise control of jet reproducibility,synchronization,and mass/velocity uniformity.To address jet nonuniformities in the coaxial plasma gun of the ShanghaiTech Gun1(STG1)facility,a high-speed imaging system utilizing intensified complementary metal oxide semiconductor(ICMOS)cameras(5120×5120 pixels,3 ns exposure)with synchronized triggering(<1μs delay,<50 ps jitter)was developed.The system's 45°×45°field of view(42×42 cm^(2)midplane coverage)and~1 mm spatial resolution enabled nonperturbative monitoring of hypersonic argon plasma jets(v_(jet)~100 km/s).Triaxial imaging(top/side/end-on views)quantified axial deviations and jet structures,while densitometric profiling derived Mach numbers through boundary spread angles.This diagnostic approach resolves critical challenges in PJMIF gun optimization,with future extensions to multi-channel imaging,narrowband spectral filtering,and 3D reconstruction. 展开更多
关键词 PJMIF coaxial plasma gun hypersonic plasma jet high-speed imaging
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Study of true coincidence summing effects on FEP efficiency of HPGe detectors during decay measurements at HIRFL
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作者 Peng-Song Zheng Fu-Rong Shi +14 位作者 Sunil Dutt Ya-Ling Zhang Yan-Shi Zhang Wei Wang Guang-Shun Li Si-Cheng Wang Hao-Ran Yang Jin-Qi He Peng-Cong Ma Jilehu Gada Xin Ma Fan-Fei Zeng Hao Huang Chen-Sheng Gao Jian-Guo Wang 《Nuclear Science and Techniques》 2025年第5期70-78,共9页
The measurement of low-level radioactivity using high-purity germanium(HPGe)detectors is important in applications such as environmental background radiation,material screening,and rare decays.The dead layers,dead zon... The measurement of low-level radioactivity using high-purity germanium(HPGe)detectors is important in applications such as environmental background radiation,material screening,and rare decays.The dead layers,dead zones,aluminum shell thickness,and diameter of Ge crystals are the most influential factors affecting the performance of HPGe detectors;hence,precise modeling of the physical conditions of the detectors is highly desirable.In this study,the GEANT4 simulation framework with an optimized detector geometry adequately replicated the experimentally recorded spectrum.These detector simulations explored the idea of realizing a dead zone(an inactive volume)at the backend of an n-type coaxial Gecrystal.Using multigamma sources,the effect of true coincidence summing(TCS)on the full energy peak(FEP)efficiency calibration of an HPGe detector was investigated as a function of sample-to-detector distance.Good agreements between the simulated and experimental efficiencies as well as the simulated and analytically calculated summing coincidence correction coefficients were achieved.At a short distance between the source and detector,calculating the correction factors for a strong source posed challenges owing to significant deadtime and pile-up effects of the detection system.The described methodology can efficiently determine summing peak probabilities at short sample-to-detector distances. 展开更多
关键词 Coaxial HPGe detector Detector characterization GEANT4 simulation Sum-peak Analytical approach Transfer reaction cross-section
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Comparative analysis on pulverized coal combustion preheated by self-sustained purifying burner with coaxial and centrosymmetric air nozzle structures:Purification,combustion and NO_(x)emission characteristics
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作者 Kun Su Ziqu Ouyang +4 位作者 Hongshuai Wang Hongliang Ding Wenyu Wang Qisi Chen Shuyun Li 《Chinese Journal of Chemical Engineering》 2025年第1期102-113,共12页
To optimize secondary air nozzle structure in purifying burner,this study focused on the comparison of purification,combustion and NO_(x)emission characteristics of pulverized coal preheated by a 30 kW purifying burne... To optimize secondary air nozzle structure in purifying burner,this study focused on the comparison of purification,combustion and NO_(x)emission characteristics of pulverized coal preheated by a 30 kW purifying burner with coaxial and centrosymmetric structures.Centrosymmetric structure shifted the position of main burning region down in high-temperature reduction unit(HTRU),and the number of branches differently influenced the temperature in different regions with this structure.For reductive gas components,CO concentration with centrosymmetric structure was higher compared to coaxial structure,while the differences in H_(2)and CH_(4)concentrations were smaller.Centrosymmetric structure was more disadvantageous to improve physicochemical properties of pulverized coal compared to coaxial structure,and this structure with four branches further deteriorated its properties compared to two branches.In mild combustion unit(MCU),the temperature at top was lower with centrosymmetric structure,while was higher in the rest.Centrosymmetric structure more effectively reduced NO_(x)emission compared to coaxial structure,but with slight sacrifice of combustion efficiency(η).Moreover,both two-branch and four-branch centrosymmetric structures realized ultra-low NO_(x)emission(<50 mg·m^(-3))with high η of over 98.50%,and the former was more advantageous.With this optimal structure,η and NO_(x)emission were 99.25%and 40.42 mg·m^(-3). 展开更多
关键词 Purifying-burning NO_(x)emission Coaxial structure Centrosymmetric structure
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Comparative investigation of the heat extraction performance of an enhanced geothermal system using H_(2),CO_(2),and H_(2)O as working fluids
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作者 Dandan Wang Xiong Wu +4 位作者 Pu Zhao Huiming Fang Zhiwei Dang Zhewei Shi Chao Huo 《Energy Geoscience》 2025年第3期75-84,共10页
The optimization of working fluids in single-well coaxial geothermal systems presents a critical pathway for advancing the use of enhanced geothermal systems(EGS)in renewable energy applications.This study evaluates t... The optimization of working fluids in single-well coaxial geothermal systems presents a critical pathway for advancing the use of enhanced geothermal systems(EGS)in renewable energy applications.This study evaluates the thermo-hydraulic performance of three working fluids(H_(2)O,CO_(2),and H_(2))in a single-well coaxial geothermal system,focusing on the effects of their injection temperatures.Using a 3D finite element model in COMSOL Multiphysics,simulations were conducted at three injection temperatures(17℃,27℃,40℃)under constant mass flow rates.The results reveal that hydrogen significantly outperforms water and carbon dioxide,achieving a 297.77% and 5453.76% higher thermal output,respectively.Notably,the heat transfer efficiency is significantly improved when the injected working fluids are at 40℃,compared to 27℃;this demonstrates a positive correlation between injection temperature and thermal recovery.Though water systems exhibit better geological compatibility,the superior thermal properties of hydrogen position it as a promising alternative-despite potential subsurface challenges.This study provides critical insights for advancing the application of high-efficiency geothermal systems as well as the development of non-aqueous working fluids,thus contributing to the sustainable utilization of geothermal energy. 展开更多
关键词 Heat extraction performance Working fluid COMSOL multiphysics Single-well coaxial tube Enhanced geothermal system
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Coaxial nano-multilayered C/SnO_(2)/TiO_(2) composites as anode materials for lithium-ion batteries
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作者 Jiao Li Haoran Liang +5 位作者 Shichao Li Jie Sun Yifan Zhang Shuxing Mei Shasha Wang Yong Zheng 《Rare Metals》 2025年第10期7118-7135,共18页
Tin dioxide(SnO_(2))with a high theoretical specific capacity of 1494 mAh g^(-1)is a promising candidate anode material for lithium storage.However,the shortcomings of serious volume expansion and low conductivity lim... Tin dioxide(SnO_(2))with a high theoretical specific capacity of 1494 mAh g^(-1)is a promising candidate anode material for lithium storage.However,the shortcomings of serious volume expansion and low conductivity limit its wide application.Herein,coaxial nano-multilayered C/SnO_(2)/TiO_(2)composites were fabricated via layerby-layer self-assembly of TiO_(2)and SnO_(2)-gel layers on the natural cellulose filter paper,followed by thermal treatment under a nitrogen atmosphere.Through engineering design of the assembly process,the optimal C/SinO_(2)/TiO_(2)composite features five alternating SnO_(2)and TiO_(2)nanolayers,with TiO_(2)as the outside shell(denoted as C/TSTST).This unique structure endows the C/TSTST with excellent structural stability and electrochemical kinetics,making it a high-performance anode for lithium-ion batteries(LIBs).The C/TSTST composite delivers a high reversible capacity of 676 mAh g^(-1)at 0.1 A g^(-1)after 200 cycles and retains a capacity of 504 mAh g^(-1)at 1.0 A g^(-1),which can be recovered to 781 mAh g^(-1)at 0.1 A g^(-1)The significantly enhanced electrochemical performance is attributed to the hierarchical hybrid structure,where the carbon core combined with coaxial TiO_(2)nanolayers serves as a structural scaffold,ameliorating volume change of SnO_(2)while creating abundant interfacial defects for enhanced lithium storage and rapid charge transport.These findings are further demonstrated by the density functional theory(DFT)calculations.This work provides an efficient strategy for designing coaxial nano-multilayered transition metal oxide-related electrode materials,offering new insights into high-performance LIBs anodes. 展开更多
关键词 C/SnO_(2)/TiO_(2) Coaxial multilayered structure Layer-by-layer self-assembly Anode materials Lithium storage
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Comparison between the SAPIEN S3 and the SAPIEN XT transcatheter heart valves:A single-center experience 被引量:2
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作者 Fadi J Sawaya Marco Spaziano +9 位作者 Thierry Lefèvre Andrew Roy Phillippe Garot Thomas Hovasse Antoinette Neylon Hakim Benamer Mauro Romano Thierry Unterseeh Marie-Claude Morice Bernard Chevalier 《World Journal of Cardiology》 2016年第12期735-745,共11页
AIM To investigate the clinical outcomes of transcatheter aortic valve implantation(TAVI) with the SAPIEN 3 transcatheter heart valve(S3-THV) vs the SAPIEN XT valve(XT-THV).METHODS We retrospectively analyzed 507 pati... AIM To investigate the clinical outcomes of transcatheter aortic valve implantation(TAVI) with the SAPIEN 3 transcatheter heart valve(S3-THV) vs the SAPIEN XT valve(XT-THV).METHODS We retrospectively analyzed 507 patients that underwent TAVI with the XT-THV and 283 patients that received the S3-THV at our institution between March 2010 and December 2015.RESULTS Thirty-day mortality(3.5% vs 8.7%:OR=0.44,P=0.21) and 1-year mortality(25.7% vs 20.1%,P=0.55) were similar in the S3-THV and the XT-THV groups.The rates of both major vascular complication and paravalvular regurgitation(PVR)>1 were almost 4 times lower in the S3-THV group than the XT-THV group(major vascular complication: 2.8% vs 9.9%,P<0.0001:PVR>1: 2.4% vs 9.7%,P<0.0001).However,the rate of new pacemaker implantation was almost twice as high in the S3-THV group(17.3% vs 9.8%,P=0.03).In the S3 group,independent predictors of new permanent pacemaker were pre-procedural RBBB(OR=4.9:P=0.001),pre-procedural PR duration(OR=1.14,P=0.05) and device lack of coaxiality(OR=1.13:P=0.05) during deployment.CONCLUSION The S3-THV is associated to lower rates of major vascular complications and PVR but higher rates of new pacemaker compared to the XT-THV.Sub-optimal visualization of the S3-THV in relation to the aortic valvular complex during deployment is a predictor of new permanent pacemaker. 展开更多
关键词 SAPIEN-3 valve Vascular complications Permanent pacemaker Lack of coaxiality Paravalvular regurgitation
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Development and Application of a Surface High-pressure Injection Device Using a Submersible Electric Pump
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作者 Li Baoyan Tian Xin +1 位作者 Wang Yong Han Shaoming 《Petroleum Science》 SCIE CAS CSCD 2005年第3期24-27,共4页
Injection recovery is an important measure for increasing the oil recovery rate of an oil field. One way is that centrifugal pumps or plunger pumps are used in an injection station to responsible for injection over a ... Injection recovery is an important measure for increasing the oil recovery rate of an oil field. One way is that centrifugal pumps or plunger pumps are used in an injection station to responsible for injection over a large area under the same pressure. This method is ineffective for low-permeability layers. For the oilfields in dispersed distribution in the marginal areas of Daqing, the low water-absorbing section needs an injection with a high delivery pressure and a low discharge capacity; another way is to install the submersible electric pump upside down, but because the submersible electric pump and the motor are underground, it is difficult for installation and maintenance. Introduced in this paper is the development and application of a surface high-pressure injection device with a submersible electric pump. Bysuccessful resolving some problems, such as the axial force of the submersible electric pump, sealing, level regulation of the pump, coaxiality and vibration, the device has the good points of running smoothly, moving easily, installation and maintains quickly and long period of running. This device can effectively solve the injection of the low water-absorbing section and of oilfields in dispersed locations. The recovery rate of oilfields is also enhanced. 展开更多
关键词 Submersible electric pump surface high-pressure injection axial force SEALING coaxiality
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Aerodynamic characteristics of rigid coaxial rotor by wind tunnel test and numerical calculation 被引量:17
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作者 Jinghui DENG Feng FAN +2 位作者 Ping'an LIU Shuilin HUANG Yongfeng LIN 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2019年第3期568-576,共9页
Focusing on aerodynamic characteristics of rigid coaxial rotor of a high-speed helicopter in hover and forward flight, a wind tunnel test is conducted in the 8 m ? 6 m low-speed straightflow wind tunnel of China Aerod... Focusing on aerodynamic characteristics of rigid coaxial rotor of a high-speed helicopter in hover and forward flight, a wind tunnel test is conducted in the 8 m ? 6 m low-speed straightflow wind tunnel of China Aerodynamics Research and Development Center. In the experiment,a 4 m diameter composite model rigid coaxial rotor is designed and manufactured, and firstorder flapping frequency ratio of the blade is 1.796 to ensure sufficient stiffness at the blade root.Rotor aerodynamic performance is measured under hovering and high advance ratio conditions.Also, the numerical method is used to calculate aerodynamic characteristics in typical states of the rigid coaxial rotor for analysis purpose. The rotor lift-drag ratio and lateral lift offset in the experiment are emphatically analyzed for the rigid coaxial rotor. The results indicate that in forward flight condition, the rotor lift-drag ratio first increases and then decreases with the increment of advance ratio and lift offset. When advance ratio remains constant, with the increment of lift offset, the lift-drag ratio of rigid coaxial rotor first increases and then decreases. 展开更多
关键词 Aerodynamic characteristics High-speed HELICOPTER Lateral LIFT OFFSET RIGID COAXIAL ROTOR Wind tunnel test
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Numerical Simulation of Unsteady Flow Around Forward Flight Helicopter with Coaxial Rotors 被引量:18
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作者 XU Heyong YE Zhengyin 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2011年第1期1-7,共7页
Three-dimensional unsteady Euler equations are numerically solved to simulate the unsteady flows around forward flight helicopter with coaxial rotors based on unstructured dynamic overset grids. The performances of th... Three-dimensional unsteady Euler equations are numerically solved to simulate the unsteady flows around forward flight helicopter with coaxial rotors based on unstructured dynamic overset grids. The performances of the two coaxial rotors both become worse because of the aerodynamic interaction between them, and the influence of the top rotor on the bottom rotor is greater than that of the bottom rotor on the top rotor. The downwash velocity at the bottom rotor plane is much larger than that at the top rotor plane, and the downwash velocity at the top rotor plane is a little larger than that at an individual rotor plane. The downwash velocity and thrust coefficient both become larger when the collective angle of blades is added. When the spacing between the two coaxial rotors increases, the thrust coefficient of the top rotor increases, but the total thrust coefficient reduces a little, because the decrease of the bottom rotor thrust coefficient is larger than the increase of the top rotor thrust coefficient. 展开更多
关键词 coaxial rotors unstructured grid overset grids thrust coefficient interaction flow helicopters numerical simulation
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Outcomes of 1.8-3.0 mm incision phacoemulsification combined with trabeculectomy for primary angle-closure glaucoma with cataract 被引量:17
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作者 Qing Wang Zheng-Xuan Jiang Rong-Feng Liao 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2020年第2期246-251,共6页
●AIM:To compare efficacy of coaxial microincisions(1.8 mm,2.2 mm)and small incisions(3.0 mm)on phacoemulsification combined with trabeculectomy for primary angle-closure glaucoma(PACG)with cataract.●METHODS:Ninety-s... ●AIM:To compare efficacy of coaxial microincisions(1.8 mm,2.2 mm)and small incisions(3.0 mm)on phacoemulsification combined with trabeculectomy for primary angle-closure glaucoma(PACG)with cataract.●METHODS:Ninety-six patients(96 eyes)with PACG and cataract were recruited and randomly divided into three groups between January 2015 and June 2017.Group A(3.0 mm incision),B(2.2 mm incision),and C(1.8 mm incision)comprised 30,34 and 32 eyes respectively.All cases were treated with clear corneal incision phacoemulsification combined with trabeculectomy.Data including best corrected visual acuity(BCVA),corneal astigmatism,corneal endothelial cell counts(CECC),intraocular pressure(IOP),and complications were collected before the operation,and at postoperative 1 d,1 and 3 mo.●RESULTS:All the patients were successfully treated with surgery.The BCVA of groups B and C were significantly improved as compared to group A at postoperative 1 d,1 and 3 mo(all P<0.05),but there was no difference between groups B and C at each time interval(all P>0.05).The corneal astigmatism of group A was statistically higher than that of group B(P=0.026);corneal astigmatism of group B was statistically higher than that of group C at postoperative 1 d(P=0.006).The corneal astigmatism of group A at postoperative 3 mo was significantly higher than that before operation(P=0.003).At postoperative 1 and 3 mo,corneal astigmatism of groups B and C were significantly lower than that of group A(all P<0.05).The CECC in group B was significantly higher than that of group A(P=0.020),and CECC in group C was significantly higher than that of group B(P=0.034)at postoperative 1 d.At postoperative 1 and 3 mo,CECC of groups B and C were significantly higher than that of group A(all P<0.05).In each group,postoperative mean IOP at each time interval was significantly lower than preoperative IOP(all P<0.05).●CONCLUSION:Coaxial microincision phacoemulsification combined with trabeculectomy for PACG with cataract has better curative efficacy in reducing postoperative corneal astigmatism and corneal endothelial cell injury than traditional small incision combined surgery,and the 1.8 mm microincision has better curative efficacy than 2.2 mm microincision in the early postoperative period. 展开更多
关键词 coaxial MICROINCISION GLAUCOMA CATARACT PHACOEMULSIFICATION TRABECULECTOMY
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Electrospun nanofibers as a wound dressing for treating diabetic foot ulcer 被引量:15
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作者 Yan Liu Shiya Zhou +1 位作者 Yanlin Gao Yinglei Zhai 《Asian Journal of Pharmaceutical Sciences》 SCIE CAS 2019年第2期130-143,共14页
Diabetes is one of the most prevalent diseases in the world with high-mortality and complex complications including diabetic foot ulcer(DFU). It has been reported that the difficulties in repairing the wound related t... Diabetes is one of the most prevalent diseases in the world with high-mortality and complex complications including diabetic foot ulcer(DFU). It has been reported that the difficulties in repairing the wound related to DFU has much relationship with the wound infection,change of inflammatory responses, lack of extracellular matrix(ECM), and the failure of angiogenesis. Following the development of medical materials and pharmaceutical technology, nanofibers has been developed by electrospinning with huge porosity, excellent humidity absorption, a better oxygen exchange rate, and some antibacterial activities. That is to say, as a potential material, nanofibers must be a wonderful candidate for the DFU treatment with so many benefits. Careful selection of polymers from natural resource and synthetic resource can widen the nanofibrous application. Popular methods applied for the nanofibrous fabrication consist of uniaxial electrospinning and coaxial electrospinning. Furthermore, nanofibers loading chemical, biochemical active pharmaceutical ingredient(API)or even stem cells can be wonderful dosage forms for the treatment of DFU. This review summarizes the present techniques applied in the fabrication of nanofibrous dressing(ND)that utilizes a variety of materials and active agents to offer a better health care for the patients suffering from DFU. 展开更多
关键词 NANOFIBERS Nanofibrous DRESSING DIABETIC foot ULCER UNIAXIAL ELECTROSPINNING Coaxial ELECTROSPINNING
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