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Reversible solid-liquid conversion enabled by self-capture effect for stable non-flow zinc-bromine batteries 被引量:1
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作者 Xixi Zhang Xiaoke Wang +7 位作者 Guangmeng Qu Tairan Wang Xiliang Zhao Jun Fan Cuiping Han Xijin Xu Chunyi Zhi Hongfei Li 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第6期1035-1044,共10页
Non-flow aqueous zinc-bromine batteries without auxiliary components(e.g.,pumps,pipes,storage tanks)and ion-selective membranes represent a cost-effective and promising technology for large-scale energy storage.Unfort... Non-flow aqueous zinc-bromine batteries without auxiliary components(e.g.,pumps,pipes,storage tanks)and ion-selective membranes represent a cost-effective and promising technology for large-scale energy storage.Unfortunately,they generally suffer from serious diffusion and shuttle of polybromide(Br^(-),Br^(3-))due to the weak physical adsorption between soluble polybromide and host carbon materials,which results in low energy efficiency and poor cycling stability.Here,we develop a novel self-capture organic bromine material(1,10-bis[3-(trimethylammonio)propyl]-4,4'-bipyridinium bromine,NVBr4)to successfully realize reversible solid complexation of bromide components for stable non-flow zinc-bromine battery applications.The quaternary ammonium groups(NV^(4+)ions)can effectively capture the soluble polybromide species based on strong chemical interaction and realize reversible solid complexation confined within the porous electrodes,which transforms the conventional“liquid-liquid”conversion of soluble bromide components into“liquid-solid”model and effectively suppresses the shuttle effect.Thereby,the developed non-flow zinc-bromide battery provides an outstanding voltage platform at 1.7 V with a notable specific capacity of 325 mAh g^(-1)NVBr4(1 A g^(-1)),excellent rate capability(200 mAh g^(-1)NVBr4 at 20 A g^(-1)),outstanding energy density of 469.6 Wh kg^(-1)and super-stable cycle life(20,000 cycles with 100%Coulombic efficiency),which outperforms most of reported zinc-halogen batteries.Further mechanism analysis and DFT calculations demonstrate that the chemical interaction of quaternary ammonium groups and bromide species is the main reason for suppressing the shuttle effect.The developed strategy can be extended to other halogen batteries to obtain stable charge storage. 展开更多
关键词 Solid-liquid conversion Self-capture Non-flow zinc-bromine batteries Quaternary ammonium
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Flow Regimes in Bubble Columns with and without Internals: A Review 被引量:1
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作者 Ayat N.Mahmood Amer A.Abdulrahman +3 位作者 Laith S.Sabri Abbas J.Sultan Hasan Shakir Majdi Muthanna H.Al-Dahhan 《Fluid Dynamics & Materials Processing》 EI 2024年第2期239-256,共18页
Hydrodynamics characterization in terms offlow regime behavior is a crucial task to enhance the design of bubble column reactors and scaling up related methodologies.This review presents recent studies on the typicalflo... Hydrodynamics characterization in terms offlow regime behavior is a crucial task to enhance the design of bubble column reactors and scaling up related methodologies.This review presents recent studies on the typicalflow regimes established in bubble columns.Some effort is also provided to introduce relevant definitions pertaining to thisfield,namely,that of“void fraction”and related(local,chordal,cross-sectional and volumetric)variants.Experimental studies involving different parameters that affect design and operating conditions are also discussed in detail.In the second part of the review,the attention is shifted to cases with internals of various types(perfo-rated plates,baffles,vibrating helical springs,mixers,and heat exchanger tubes)immersed in the bubble columns.It is shown that the presence of these elements has a limited influence on the global column hydrodynamics.However,they can make the homogeneousflow regime more stable in terms of transition gas velocity and transi-tion holdup value.The last section is used to highlight gaps which have not beenfilled yet and future directions of investigation. 展开更多
关键词 HYDRODYNAMICS ow regime bubble column heat-exchanging internals
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A dual-RPA based lateral flow strip for sensitive,on-site detection of CP4-EPSPS and Cry1Ab/Ac genes in genetically modified crops 被引量:1
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作者 Jinbin Wang Yu Wang +7 位作者 Xiuwen Hu Yifan Chen Wei Jiang Xiaofeng Liu Juan Liu Lemei Zhu Haijuan Zeng Hua Liu 《Food Science and Human Wellness》 SCIE CSCD 2024年第1期183-190,共8页
Traditional transgenic detection methods require high test conditions and struggle to be both sensitive and efficient.In this study,a one-tube dual recombinase polymerase amplification(RPA)reaction system for CP4-EPSP... Traditional transgenic detection methods require high test conditions and struggle to be both sensitive and efficient.In this study,a one-tube dual recombinase polymerase amplification(RPA)reaction system for CP4-EPSPS and Cry1Ab/Ac was proposed and combined with a lateral flow immunochromatographic assay,named“Dual-RPA-LFD”,to visualize the dual detection of genetically modified(GM)crops.In which,the herbicide tolerance gene CP4-EPSPS and the insect resistance gene Cry1Ab/Ac were selected as targets taking into account the current status of the most widespread application of insect resistance and herbicide tolerance traits and their stacked traits.Gradient diluted plasmids,transgenic standards,and actual samples were used as templates to conduct sensitivity,specificity,and practicality assays,respectively.The constructed method achieved the visual detection of plasmid at levels as low as 100 copies,demonstrating its high sensitivity.In addition,good applicability to transgenic samples was observed,with no cross-interference between two test lines and no influence from other genes.In conclusion,this strategy achieved the expected purpose of simultaneous detection of the two popular targets in GM crops within 20 min at 37°C in a rapid,equipmentfree field manner,providing a new alternative for rapid screening for transgenic assays in the field. 展开更多
关键词 Genetically modifi ed crops On-site detection Lateral fl ow test strips Dual recombinase polymerase amplification (RPA)
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Analysis of Snow Distribution and Displacement in the Bogie Region of a High-Speed Train 被引量:1
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作者 Zhihui Du Mengge Yu +1 位作者 Jiali Liu Xiulong Yao 《Fluid Dynamics & Materials Processing》 EI 2024年第7期1687-1701,共15页
Snow interacting with a high-speed train can cause the formation of ice in the train bogie region and affect its safety.In this study,a wind-snow multiphase numerical approach is introduced for high-speed train bogies... Snow interacting with a high-speed train can cause the formation of ice in the train bogie region and affect its safety.In this study,a wind-snow multiphase numerical approach is introduced for high-speed train bogies on the basis of the Euler-Lagrange discrete phase model.A particle-wall impact criterion is implemented to account for the presence of snow particles on the surface.Subsequently,numerical simulations are conducted,considering various snow particle diameter distributions and densities.The research results indicate that when the particle diameter is relatively small,the distribution of snow particles in the bogie cavity is relatively uniform.However,as the particle diameter increases,the snow particles in the bogie cavity are mainly located in the rear wheel pairs of the bogie.When the more realistic Rosin-Rammler diameter distribution is applied to snow particles,the positions of snow particles with different diameters vary in the bogie cavity.More precisely,smaller diameter particles are primarily located in the front and upper parts of the bogie cavity,while larger diameter snow particles accumulate at the rear and in the lower parts of the bogie cavity. 展开更多
关键词 BOGIE the wind-snow multiphaseflow model particle diameter distribution
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直播信息特性和产品感知对冲动购买的影响研究——基于Howard-Sheth模型 被引量:1
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作者 刘人铭 《中国商论》 2024年第3期29-32,共4页
基于Howard-Sheth模型,本文从外部信息和感知刺激角度实证探索社交电商直播信息特征和产品感知价值对冲动购买意愿的影响机制,采取便利性抽样收集245份有效问卷,运用AMOS-结构方程模型对效应路径进行实证检验。结果表明:社交电商直播信... 基于Howard-Sheth模型,本文从外部信息和感知刺激角度实证探索社交电商直播信息特征和产品感知价值对冲动购买意愿的影响机制,采取便利性抽样收集245份有效问卷,运用AMOS-结构方程模型对效应路径进行实证检验。结果表明:社交电商直播信息交互性、产品感知享乐价值和感知实用价值对心流体验有显著的促进作用,心流体验进一步影响消费者冲动购买意愿;信息时效性对心流体验的影响不显著。基于此,文章通过将Howard-Sheth模型拓展到社交电商直播场景中,并为社交电商提出几点营销思考进而为电子商务行业理解社交电商消费者行为提供了新视角。 展开更多
关键词 冲动购买 Howard-Sheth模型 信息质量 感知价值 心流体验
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Double-Doped Carbon-Based Electrodes with Nitrogen and Oxygen to Boost the Areal Capacity of Zinc-Bromine Flow Batteries
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作者 Xiaoyun Sun Deren Wang +4 位作者 Haochen Hu Xin Wei Lin Meng Zhongshan Ren Sensen Li 《Transactions of Tianjin University》 EI CAS 2024年第1期74-89,共16页
Ensuring a stable power output from renewable energy sources,such as wind and solar energy,depends on the development of large-scale and long-duration energy storage devices.Zinc–bromine fl ow batteries(ZBFBs)have em... Ensuring a stable power output from renewable energy sources,such as wind and solar energy,depends on the development of large-scale and long-duration energy storage devices.Zinc–bromine fl ow batteries(ZBFBs)have emerged as cost-eff ective and high-energy-density solutions,replacing expensive all-vanadium fl ow batteries.However,uneven Zn deposition during charging results in the formation of problematic Zn dendrites,leading to mass transport polarization and self-discharge.Stable Zn plating and stripping are essential for the successful operation of high-areal-capacity ZBFBs.In this study,we successfully synthesized nitrogen and oxygen co-doped functional carbon felt(NOCF4)electrode through the oxidative polymerization of dopamine,followed by calcination under ambient conditions.The NOCF4 electrode eff ectively facilitates effi cient“shuttle deposition”of Zn during charging,signifi cantly enhancing the areal capacity of the electrode.Remarkably,ZBFBs utilizing NOCF4 as the anode material exhibited stable cycling performance for 40 cycles(approximately 240 h)at an areal capacity of 60 mA h/cm^(2).Even at a high areal capacity of 130 mA h/cm^(2),an impressive energy effi ciency of 76.98%was achieved.These fi ndings provide a promising pathway for the development of high-areal-capacity ZBFBs for advanced energy storage systems. 展开更多
关键词 Zinc-bromine fl ow batteries N O co-doping Areal capacity Shuttle deposition Zinc dendrite
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Pairing nitroxyl radical and phenazine with electron-withdrawing/-donating substituents in “water-in-ionic liquid” for high-voltage aqueous redox flow batteries
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作者 Zhifeng Huang Rolf Hempelmann +2 位作者 Yiqiong Zhang Li Tao Ruiyong Chen 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第4期713-722,共10页
Aqueous redox-active organic materials-base electrolytes are sustainable alternatives to vanadium-based electrolyte for redoxflow batteries(RFBs)due to the advantages of high ionic conductivity,environmentally benign,s... Aqueous redox-active organic materials-base electrolytes are sustainable alternatives to vanadium-based electrolyte for redoxflow batteries(RFBs)due to the advantages of high ionic conductivity,environmentally benign,safety and low cost.However,the underexplored redox properties of organic materials and the narrow thermodynamic electrolysis window of water(1.23 V)hinder their wide applications.Therefore,seeking suitable organic redox couples and aqueous electrolytes with a high output voltage is highly suggested for advancing the aqueous organic RFBs.In this work,the functionalized phenazine and nitroxyl radical with electron-donating and electron-withdrawing group exhibit redox potential of-0.88 V and 0.78 V vs.Ag,respectively,in“water-in-ionic liquid”supporting electrolytes.Raman spectra reveal that the activity of water is largely suppressed in“water-in-ionic liquid”due to the enhanced hydrogen bond interactions between ionic liquid and water,enabling an electrochemical stability window above 3 V.“Water-in-ionic liquid”supporting electrolytes help to shift redox potential of nitroxyl radical and enable the redox activity of functionalized phenazine.The assembled aqueous RFB allows a theoretical cell voltage of 1.66 V and shows a practical discharge voltage of 1.5 V in the“water-in-ionic liquid”electrolytes.Meanwhile,capacity retention of 99.91%per cycle is achieved over 500 charge/discharge cycles.A power density of 112 mW cm^(-2) is obtained at a current density of 30 mA cm^(-2).This work highlights the importance of rationally combining supporting electrolytes and organic molecules to achieve high-voltage aqueous RFBs. 展开更多
关键词 Aqueous redoxflow batteries Water-in-ionic liquid electrolytes High-voltage aqueous batteries Organic redox-active materials
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Simulation of Two-Phase Flowback Phenomena in Shale Gas Wells
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作者 Yongwei Duan Zhaopeng Zhu +2 位作者 Hui He Gaoliang Xuan Xuemeng Yu 《Fluid Dynamics & Materials Processing》 EI 2024年第2期349-364,共16页
The gas-water two-phaseflow occurring as a result of fracturingfluidflowback phenomena is known to impact significantly the productivity of shale gas well.In this work,this two-phaseflow has been simulated in the framework... The gas-water two-phaseflow occurring as a result of fracturingfluidflowback phenomena is known to impact significantly the productivity of shale gas well.In this work,this two-phaseflow has been simulated in the framework of a hybrid approach partially relying on the embedded discrete fracture model(EDFM).This model assumes the region outside the stimulated reservoir volume(SRV)as a single-medium while the SRV region itself is described using a double-medium strategy which can account for thefluid exchange between the matrix and the micro-fractures.The shale gas adsorption,desorption,diffusion,gas slippage effect,fracture stress sensitivity,and capillary imbibition have been considered.The shale gas production,pore pressure distribution and water saturation distribution in the reservoir have been simulated.The influences of hydraulic fracture geometry and nonorthogonal hydraulic fractures on gas production have been determined and discussed accordingly.The simulation results show that the daily gas production has an upward and downward trend due to the presence of a large amount of fracturingfluid in the reservoir around the hydraulic fracture.The smaller the angle between the hydraulic fracture and the wellbore,the faster the daily production of shale gas wells decreases,and the lower the cumulative production.Nonplanar fractures can increase the control volume of hydraulic fractures and improve the production of shale gas wells. 展开更多
关键词 Shale gas fracturingfluid backflow the stimulated reservoir volume gas-water two-phase production
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基于VRB/OW-GFRP混合结构的CTB电池包上盖总成轻量化设计研究 被引量:5
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作者 段利斌 张雨 +5 位作者 杜展鹏 刘冶钢 孟祥新 田冠男 郑海洋 吴闯 《汽车工程》 EI CSCD 北大核心 2024年第2期290-299,共10页
电池车身一体化(CTB)是提升电动汽车续航里程的关键技术。利用胶接工艺将变厚度(VRB)结构与正交编织玻璃纤维增强复合材料(OW-GFRP)粘接形成的VRB/OW-GFRP混合结构,是降低CTB电池包质量的创新结构,有助于进一步提升电动汽车的续航里程... 电池车身一体化(CTB)是提升电动汽车续航里程的关键技术。利用胶接工艺将变厚度(VRB)结构与正交编织玻璃纤维增强复合材料(OW-GFRP)粘接形成的VRB/OW-GFRP混合结构,是降低CTB电池包质量的创新结构,有助于进一步提升电动汽车的续航里程。以某款电动汽车为研究对象,设计了一种CTB电池车身一体化结构,实现了电池包上盖与车身地板的集成融合。分别采用VRB结构、UT/OW-GFRP及VRB/OW-GFRP混合结构替代等厚度(UT)CTB电池包上盖总成,并基于多阶段优化方法开展了3种类型CTB电池包上盖总成的轻量化设计。结果表明,在满足CTB电池包刚度性能前提下,VRB结构相比UT结构实现减质量6.4%;基于VRB/OW-GFRP混合结构的CTB电池包上盖总成轻量化效果约为金属结构的3倍,VRB/OW-GFRP相比UT/OW-GFRP混合电池包上盖总成进一步减质量4.2%。由此可见,VRB/OW-GFRP混合结构是未来汽车轻量化技术发展的重要趋势,在CTB电池包上盖总成中具有巨大的应用前景。 展开更多
关键词 变厚度/正交编织玻璃纤维增强复合材料 混合结构 电池车身一体化 电池包 轻量化
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Prevention and Cure of Acute Alcohol Intoxication in Mice by Administration of Compound of Japanese Raisintree Fruit, Lobed Kudzuvine Flower Bud and Lightyellow Sophora Root 被引量:2
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作者 孔玲 李杰 张秀珍 《Agricultural Science & Technology》 CAS 2014年第5期874-876,881,共4页
[Objective] We aimed to investigate the preventive and therapeutical effect of compound of traditional Chinese drugs (Japanese raisintree fruit, lobed kudzuvine flower bud and lightyel ow sophora root) on acute alc... [Objective] We aimed to investigate the preventive and therapeutical effect of compound of traditional Chinese drugs (Japanese raisintree fruit, lobed kudzuvine flower bud and lightyel ow sophora root) on acute alcohol intoxication in mice. [Method] Acute alcohol intoxication was induced by administering alcohol to mice. Three different doses (low, middle and high) of compound of traditional Chinese drugs were administered to mice before and after administering alcohol respectively to investigate the preventive and therapeutical effect of drugs on acute alcohol intox-ication through doing statistical analysis about drunk mice and their sleeping time. The concentration of malondialdehyde (MDA), reduced glutathione (GSH) and triglyc-erides (TG) in liver was also determined to investigate the protective effect of drugs on liver. [Result] The efficacy of compound of traditional Chinese drugs on acute al-cohol intoxication was dose-dependent. High-dose administration decreased the number of drunk mice significantly compared with control group; middle- and high-dose administration reduced the sleeping time of drunk mice and the concentration of MDA and TG in liver tissue; three doses al increased the concentration of GSH. [Conclusion] The compound of Japanese raisintree fruit, lobed kudzuvine flower bud and lightyel ow sophora root had preventive and therapeutical effect on hangover, and it also had certain preventive and therapeutical effect on liver damage caused by alcohol. 展开更多
关键词 Japanese raisintree fruit Lobed kudzuvine flower bud Lightyel ow sophora root Acute alcohol intoxication Anti-drunk Sobering effect
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Comparison of 2D and 4D Flow MRI Measurements for Hemodynamic Evaluation of the Fontan Palliation
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作者 Elisa Listo Nicola Martini +8 位作者 Stefano Salvadori Elisa Valenti Nicola Stagnaro Gianluca Trocchio Chiara Marrone Alberto Clemente Francesca Raimondi Pierluigi Festa Lamia Ait Ali 《Congenital Heart Disease》 SCIE 2023年第6期627-638,共12页
Background:The assessment of Fontan circuit’sflow is traditionally evaluated by multiple through-plane phase-contrast MRI acquisitions(2Dflow),while recently,a single volumetric 4D-flow MRI acquisition is emerging as a ... Background:The assessment of Fontan circuit’sflow is traditionally evaluated by multiple through-plane phase-contrast MRI acquisitions(2Dflow),while recently,a single volumetric 4D-flow MRI acquisition is emerging as a comprehensive tool for the hemodynamic evaluation in congenital heart diseases.Purpose:To compare 2D and 4D-flow MRI measurements in patients after Fontan palliation and to evaluate parameters affecting potential dis-agreement.Methods:39 patients after Fontan palliation(23 males,age 22±11 years)who underwent cardiac MRI with 2D and 4D-flow MRI acquisition were included in the study.In all patients,bloodflow quantification in the Fontan circuit and aorta by 2Dflow and by 4Dflow MRI acquisition blinding to the 2D results was per-formed.The agreement between 2D and 4D-flow MRI was calculated as the intraclass correlation coefficient(ICC).The mean absolute differences between 4D and 2Dflows were analyzed using linear regression models.Results:4D-flow MRI acquisition time was slightly lower than 2D(7.6±1.8 min vs.9.4±3.3 min,p=0.03).Flow was slightly predominant in the right pulmonary artery(58%of total pulmonaryflow).Conduit/tunnel-pul-monary arteriesflow accounted for 60%of the Fontan circuit.Agreement between 2D and 4D was overall good-to-excellent from ICC:0.81795%CI:0.637–0.907 to 0.93295%CI:0.866–0.965.There was no significant influ-ence of evaluated parameters on the agreement on 4D and 2Dflow.Conclusions:4D-flow MRI represents a valid tool in Fontan’sflow quantification.Further larger studies are needed to confirm our results and to evaluate the impact of advanced 4D-flow MRI parameters on the prognostic stratification in patients after Fontan palliation. 展开更多
关键词 Fontan palliation fontanflows 4Dflow MRI 2Dflow MRI cardiac magnetic resonance
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OWE-SOJ技术及核迁移试验在香菇交配型因子鉴定中的应用 被引量:21
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作者 林芳灿 汪中文 +2 位作者 熊再明 代江红 闵家顺 《华中农业大学学报》 CAS CSCD 北大核心 2000年第6期573-576,共4页
由于没有明确的形态差异 ,香菇的 3种不亲和交配反应即A =B =,A =B≠和A≠B =难以互相区别。本研究将OWE SOJ技术及核迁移试验用于香菇的交配型分析。结果表明 ,应用OWE SOJ技术 ,可以观察到 3种不同的菌落形态 :由A≠B≠配对形成的具... 由于没有明确的形态差异 ,香菇的 3种不亲和交配反应即A =B =,A =B≠和A≠B =难以互相区别。本研究将OWE SOJ技术及核迁移试验用于香菇的交配型分析。结果表明 ,应用OWE SOJ技术 ,可以观察到 3种不同的菌落形态 :由A≠B≠配对形成的具锁状联合的绒毛状菌落 ,由A≠B =配对形成的无锁状联合的栅栏型菌落及由A =B =或A =B≠配对形成的无锁状联合的绒毛状菌落。通过一个附加的常规交配试验 ,A =B =和A=B≠反应易于互相区别开来。核迁移试验表明 ,核迁移出现于A =B≠反应中而不出现于A≠B =反应中。这一结果与OWE SOJ试验的结果是一致的。因此 ,在常规交配型分析的基础上 ,应用OWE SOJ技术及核迁移试验以准确地鉴定样本中所有单核体的交配型因子是可行的。 展开更多
关键词 香菇 交配型 owE-SOJ技术 核迁移试验
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欧前胡素衍生物OW1对血管舒张作用及机制研究 被引量:1
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作者 周楠 张丹 +3 位作者 李黎 张鹏 左燕 朱亚宁 《中国药学杂志》 CAS CSCD 北大核心 2018年第22期1921-1926,共6页
目的考察欧前胡素衍生物OW1对大鼠不同动脉的舒张作用,并探讨其可能的舒张作用机制。方法采用多通道微血管张力测定方法,以高钾预收缩的大鼠主动脉、肾动脉、大脑中动脉、冠状动脉、肺动脉以及肠系膜动脉,评价OW1对这6种动脉的舒张效应... 目的考察欧前胡素衍生物OW1对大鼠不同动脉的舒张作用,并探讨其可能的舒张作用机制。方法采用多通道微血管张力测定方法,以高钾预收缩的大鼠主动脉、肾动脉、大脑中动脉、冠状动脉、肺动脉以及肠系膜动脉,评价OW1对这6种动脉的舒张效应;分别考察内皮、β-肾上腺素受体、3种钾离子通道考察其对OW1舒张曲线的影响;干预细胞内钙及外钙的浓度,检测其对OW1抑制收缩曲线的影响。结果 OW1可以完全舒张上述6种动脉,E_(max)均在90%以上,p EC_(50)分别为(6. 11±0. 09),(5. 76±0. 01),(6. 22±0. 08),(5. 78±0. 05),(5. 65±0. 01)和(6. 59±0. 07)。阻断内皮、β-肾上腺素受体、ATP敏感性钾通道和内向整流钾通道后均对OW1的舒张曲线无影响,阻断钙离子激活钾离子通道可使OW1的舒张曲线明显地非平行性右移,E_(max)降低,并且OW1可以抑制外钙的内流以及内钙的释放,降低细胞内的钙离子浓度,从而抑制血管收缩。结论 OW1可以舒张上述6种血管,其涉及的血管舒张机制主要包括抑制电压依赖性钙通道和受体介导的Ca^(2+)的内流和释放。 展开更多
关键词 欧前胡素衍生物ow1 血管舒张 钙离子通道 降压药物
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基于Web搜索搭建OWS索引服务中心 被引量:1
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作者 刘钊 吴泳锋 +1 位作者 朱小冬 王宏亮 《测绘通报》 CSCD 北大核心 2008年第4期55-57,共3页
OWS(OGC Web Service)为空间数据共享提供了可行的方法,但如何在浩瀚的互联网上快速、准确地查询到符合用户需要的OWS是一件比较困难的事情。在对Web搜索方法进行深入理解的基础上,提出一种基于全文检索搜索引擎搭建OWS索引服务的思路,... OWS(OGC Web Service)为空间数据共享提供了可行的方法,但如何在浩瀚的互联网上快速、准确地查询到符合用户需要的OWS是一件比较困难的事情。在对Web搜索方法进行深入理解的基础上,提出一种基于全文检索搜索引擎搭建OWS索引服务的思路,并采用Google实现了OWS索引服务中心的原型系统,该系统可以为互联网用户提供OWS搜索服务。 展开更多
关键词 owS索引服务 OGC WEB SERVICE 全文检索搜索
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OW式永磁直驱风电系统不连续脉宽调制 被引量:3
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作者 殷杰 向铁元 杨瑶 《电机与控制应用》 北大核心 2015年第7期62-66,74,共6页
针对中压永磁直驱风电系统(PMSG)运行中存在的电流脉动问题,提出一种OW式永磁直驱风电系统不连续PWM调制方法。建立了OW双逆变器PMSG驱动系统等效开关模型,阐明了解耦PWM调制电流脉动问题的本质原因,引入"有效时间"概念,通过... 针对中压永磁直驱风电系统(PMSG)运行中存在的电流脉动问题,提出一种OW式永磁直驱风电系统不连续PWM调制方法。建立了OW双逆变器PMSG驱动系统等效开关模型,阐明了解耦PWM调制电流脉动问题的本质原因,引入"有效时间"概念,通过合理地偏移有效电压矢量作用时间,解决了PMSG机侧定子电流脉动问题,实现了PMSG变流器发电品质的优化提高。最后,基于110 kW风力发电对拖试验平台对所提OW PMSG不连续PWM调制方法进行性能验证,验证了该方法对优化PMSG并网电能品质的有效性。 展开更多
关键词 风力发电 永磁直驱发电 定子ow 不连续PWM
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OWE-SOJ技术在鉴定香菇交配反应中的应用(英文) 被引量:3
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作者 林芳灿 汪中文 代江红 《食用菌学报》 2000年第4期8-10,共3页
在香菇中 ,由于没有明确的形态差别 ,3种不亲和交配反应 ,即A =B =,A =B≠andA≠B =无法彼此区别。本研究将一种称为OWE -SOJ的新技术应用于香菇单孢分离物的对峙培养。结果表明 ,A≠B≠形成具有锁状联合的绒毛状菌落 ,A≠B =形成没有... 在香菇中 ,由于没有明确的形态差别 ,3种不亲和交配反应 ,即A =B =,A =B≠andA≠B =无法彼此区别。本研究将一种称为OWE -SOJ的新技术应用于香菇单孢分离物的对峙培养。结果表明 ,A≠B≠形成具有锁状联合的绒毛状菌落 ,A≠B =形成没有锁状联合的栅栏型菌落。A =B =和A =B≠都形成无锁状联合的绒毛状菌落 ,但通过一个附加的常规交配试验 ,二者易于相互区别。因此 ,在通常的交配试验基础上 ,应用OWE -SOJ技术准确鉴定 4种不同的交配反应是可行的。 展开更多
关键词 香菇 owE-SOJ技术 交配反应 鉴定方法
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Numerical simulation and disaster prevention for catastrophic fire airflow of main air-intake belt roadway in coal mine—A case study 被引量:9
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作者 周刚 程卫民 +4 位作者 张睿 沈宝堂 聂文 张磊 王昊 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第6期2359-2368,共10页
Coal mine belt fire develops very rapidly and is difficult to control. If not suppressed quickly, a belt fire could easily lead to airflow disorder and undermine the ventilation system. However, belt fire can be preve... Coal mine belt fire develops very rapidly and is difficult to control. If not suppressed quickly, a belt fire could easily lead to airflow disorder and undermine the ventilation system. However, belt fire can be prevented effectively by establishing fire airflow control system. In this work, the 5th belt roadway of Kongzhuang coal mine was taken as the object of investigation, where geometrical models of this roadway were established firstly. Then, based on mathematical model of fire smoke flow, the CO volume fraction, smoke density distribution, air temperature and pollutant velocity vector in the roadway before and after taking airflow control measures were simulated by using Fluent software. It can be known from the simulation that with the normal ventilation status in 5th belt roadway, the countercurrent of smoke does not happen when a fire occurs; the roadway's section is almost filled with CO at 10 m downstream from the fire source, and with air velocity getting stable gradually, the CO concentration reaches about 15 %. After taking airflow control measures, the effect range of temperature field which are harmful to the miners decreases from 69 m to 30 m; and the distance of the roadway fully filled with CO is 5 m farther than that before taking measures. Finally, according to the numerical simulation results and the actual condition of the belt roadway, the warning and automatic remote airflow control system with short-circuit method for the 5th belt roadway was designed to guarantee the safety production. 展开更多
关键词 belt roadway fire catastrophic airf ow numerical simulation flow pattern early warning and control
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TCP Slow Start阶段流量稳定现象的研究
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作者 时培昕 孙有越 雷振明 《计算机工程与应用》 CSCD 北大核心 2003年第15期23-26,共4页
该文提出了在TCPSlowStart阶段出现的一种流量稳定的现象,并对这种现象产生的原因进行了详尽的分析,然后通过仿真试验,验证了自己的观点,并说明了这种现象对Internet流量研究的重要性。
关键词 TCP S1ow START 流量稳定 自相似
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一个AR模型降阶函数OWE(n)
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作者 赵剡 俞文伯 杨博 《火炮发射与控制学报》 北大核心 2002年第3期13-15,18,共4页
提出了一个欠拟合模型定阶函数 OWE(n),仿真结果表明把 OWE(n)作为用低阶模型代替高阶模型的适用性判断准则,可以得到有效的模型简化。将 OWE(n)应用于 GPS 系统的选择可用性(SA)信号的建模研究,获得了很好的结果。
关键词 AR模型 降阶函数 owE(n) 建模 GPS 全球定位系统
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