期刊文献+
共找到5,402篇文章
< 1 2 250 >
每页显示 20 50 100
The characteristics of negative corona discharge and radio interference at different altitudes based on coaxial wire-cylinder gap
1
作者 何旺龄 魏宏宇 +6 位作者 张胤禄 刘永聪 刘云鹏 万保权 周阳 王延召 干喆渊 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第2期77-85,共9页
The corona discharge from transmission lines in high-altitude areas is more severe than at lower altitudes. The radio interference caused thereby is a key factor to be considered when designing transmission lines. To ... The corona discharge from transmission lines in high-altitude areas is more severe than at lower altitudes. The radio interference caused thereby is a key factor to be considered when designing transmission lines. To study the influence of altitude on negative corona characteristics, an experimental platform comprising a movable small corona cage was established: experiments were conducted at four altitudes in the range of 1120-4320 m, and data on the corona current pulse and radio interference level of 0.8-mm diameter fine copper wire under different negative voltages were collected. The experimental results show that the average amplitude, repetition frequency and average current of the corona current pulse increase with increasing altitude. The dispersion of pulse amplitude increases with increase in altitude, while the randomness of the pulse interval decreases continuously. Taking the average current as an intermediate variable,the relationship between radio interference level and altitude is obtained. The result of this research has some significance for understanding the corona discharge characteristics of ultra-highvoltage lines. 展开更多
关键词 ALTITUDE negative corona corona current pulse radio interference level
下载PDF
Observation of Standing Slow Magneto-acoustic Waves in a Flaring Active Region Corona Loop
2
作者 A.Abedini 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第10期170-179,共10页
Intensity fluctuations are frequently observed in different regions and structures of the solar corona.These fluctuations may be caused by magneto-hydrodynamic(MHD)waves in coronal plasma.MHD waves are prime candidate... Intensity fluctuations are frequently observed in different regions and structures of the solar corona.These fluctuations may be caused by magneto-hydrodynamic(MHD)waves in coronal plasma.MHD waves are prime candidates for the dynamics,energy transfer,and anomalous temperature of the solar corona.In this paper,analysis is conducted on intensity and temperature fluctuations along the active region coronal loop(NOAA AR 13599)near solar flares.The intensity and temperature as functions of time and distance along the loop are extracted using images captured by the Atmospheric Imaging Assembly(AIA)instrument onboard the Solar Dynamics Observatory(SDO)space telescope.To observe and comprehend the causes of intensity and temperature fluctuations,after conducting initial processing,and applying spatial and temporal frequency filters to data,enhanced distance-time maps of these variables are drawn.The space-time maps of intensities show standing oscillations at wavelengths of 171,193,and 211A with greater precision and clarity than earlier findings.The amplitude of these standing oscillations(waves)decreases and increases over time.The average values of the oscillation period,damping time,damping quality,projected wavelength,and projected phase speed of standing intensity oscillations are in the range of 15-18 minutes,24-31 minutes,1.46″-2″,132″-134″,and 81-100 km s^(-1),respectively.Also,the differential emission measure peak temperature values along the loop are found in the range of 0.51-3.98 MK,using six AIA passbands,including 94,131,171,193,211,and 335?.Based on the values of oscillation periods,phase speeds,damping time,and damping quality,it is inferred that the fluctuations in intensity are related to standing slow magneto-acoustic waves with weak damping. 展开更多
关键词 magnetohydrodynamics(MHD) waves Sun:corona Sun:atmosphere Sun:flares
下载PDF
Non-thermal atmospheric-pressure positive pulsating corona discharge in degradation of textile dye Reactive Blue 19 enhanced by Bi_(2)O_(3) catalyst
3
作者 Milica PETROVIC Dragan RADIVOJEVIC +4 位作者 Sasa RANCEV Nena VELINOV Milos KOSTIC Danijela BOJIC Aleksandar BOJIC 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第2期104-113,共10页
In this work,monoclinic Bi_(2)O_(3) was applied for the first time,to the best of our knowledge,as a catalyst in the process of dye degradation by a non-thermal atmospheric-pressure positive pulsating corona discharge... In this work,monoclinic Bi_(2)O_(3) was applied for the first time,to the best of our knowledge,as a catalyst in the process of dye degradation by a non-thermal atmospheric-pressure positive pulsating corona discharge.The research focused on the interaction of the plasma-generated species and the catalyst,as well as the role of the catalyst in the degradation process.Plasma decomposition of the anthraquinone reactive dye Reactive Blue 19(RB 19) was performed in a selfmade reactor system.Bi_(2)O_(3) was prepared by electrodeposition followed by thermal treatment,and characterized by x-ray diffraction,scanning electron microscopy and energy-dispersive xray techniques.It was observed that the catalyst promoted decomposition of plasma-generated H_(2)O_(2) into ·OH radicals,the principal dye-degrading reagent,which further attacked the dye molecules.The catalyst improved the decolorization rate by 2.5 times,the energy yield by 93.4%and total organic carbon removal by 7.1%.Excitation of the catalyst mostly occurred through strikes by plasma-generated reactive ions and radical species from the air,accelerated by the electric field,as well as by fast electrons with an energy of up to 15 eV generated by the streamers reaching the liquid surface.These strikes transferred the energy to the catalyst and created the electrons and holes,which further reacted with H_(2)O_(2) and water,producing ·OH radicals.This was indentified as the primary role of the catalyst in this process.Decolorization reactions followed pseudo first-order kinetics.Production of H_(2)O_(2) and the dye degradation rate increased with increase in the input voltage.The optimal catalyst dose was 500 mg·dm^(-3).The decolorization rate was a little lower in river water compared with that in deionized water due to the side reactions of ·OH radicals with organic matter and inorganic ions dissolved in the river water. 展开更多
关键词 corona RB 19 Bi_(2)O_(3) CATALYST DEGRADATION
下载PDF
Electromagnetic Ion Beam Instability in the Solar Corona
4
作者 Wen Liu Jin-Song Zhao +2 位作者 De-Jin Wu Huan-Yu Jia Si-Ming Liu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第2期171-179,共9页
Remote-sensing measurements indicate that heavy ions in the corona undergo an anisotropic and mass-charge dependent energization.A popular explanation to this phenomenon is the damping of the Alfven/ion cyclotron wave... Remote-sensing measurements indicate that heavy ions in the corona undergo an anisotropic and mass-charge dependent energization.A popular explanation to this phenomenon is the damping of the Alfven/ion cyclotron waves.In this paper,we propose that the ion beam instability can be an important source of the Alfven/ion cyclotron waves,and we study the excitation of the ion beam instability in the corona at the heliocentric distance~3R_(⊙)and the corresponding energy transfer process therein ba sed on plasma kinetic theory.The results indicate that the existence of the motionless heavy ions inhibits the ion beam instability.However,the anisotropic beams of heavy ions promote the excitation of the ion beam instability.Besides,the existence ofαbeams can provide a second energy source for exciting beam instability.However,when both the proton beam and the a beam reach the instability excitation threshold,the proton beam driven instability excites preferentially.Moreover,the excitation threshold of the Alfven/ion cyclotron instability driven by ion beam is of the local Alfven speed or even less in the corona. 展开更多
关键词 plasmas-instabilities-waves-Sun corona
下载PDF
End-to-end computational design for an EUV solar corona multispectral imager with stray light suppression
5
作者 Jinming Gao Yue Sun +6 位作者 Yinxu Bian Jilong Peng Qian Yu Cuifang Kuang Xiangzhao Wang Xu Liu Xiangqun Cui 《Astronomical Techniques and Instruments》 CSCD 2024年第1期31-41,共11页
An extreme ultraviolet solar corona multispectral imager can allow direct observation of high temperature coronal plasma,which is related to solar flares,coronal mass ejections and other significant coronal activities... An extreme ultraviolet solar corona multispectral imager can allow direct observation of high temperature coronal plasma,which is related to solar flares,coronal mass ejections and other significant coronal activities.This manuscript proposes a novel end-to-end computational design method for an extreme ultraviolet(EUV)solar corona multispectral imager operating at wavelengths near 100 nm,including a stray light suppression design and computational image recovery.To suppress the strong stray light from the solar disk,an outer opto-mechanical structure is designed to protect the imaging component of the system.Considering the low reflectivity(less than 70%)and strong-scattering(roughness)of existing extreme ultraviolet optical elements,the imaging component comprises only a primary mirror and a curved grating.A Lyot aperture is used to further suppress any residual stray light.Finally,a deep learning computational imaging method is used to correct the individual multi-wavelength images from the original recorded multi-slit data.In results and data,this can achieve a far-field angular resolution below 7",and spectral resolution below 0.05 nm.The field of view is±3 R_(☉)along the multi-slit moving direction,where R☉represents the radius of the solar disk.The ratio of the corona's stray light intensity to the solar center's irradiation intensity is less than 10-6 at the circle of 1.3 R_(☉). 展开更多
关键词 EUV solar corona imager Curved grating Stray light suppression Computational multispectral imaging
下载PDF
Corona渲染技术在室内效果图仿真制作中的应用教学——以“教研室办公空间”效果图制作为例
6
作者 冯韬 周肖 《广西教育》 2024年第3期164-168,共5页
Corona是一款建筑可视化渲染器,可作为插件集成在3ds Max中,它渲染设置简单,可在浮动视口开启交互式渲染并实时观察渲染结果,可以渲染出照片级写实的室内效果图。以“教研室办公空间”Corona渲染为例,基于3ds Max通过硬装材质赋予、硬... Corona是一款建筑可视化渲染器,可作为插件集成在3ds Max中,它渲染设置简单,可在浮动视口开启交互式渲染并实时观察渲染结果,可以渲染出照片级写实的室内效果图。以“教研室办公空间”Corona渲染为例,基于3ds Max通过硬装材质赋予、硬装场景灯光设置、硬装场景摄影机创建及视口设置,完成软装和渲染输出,从而阐明Corona渲染器在室内设计项目、室内设计专业教学中的应用,为其他室内效果图仿真提供技术参考。 展开更多
关键词 效果图 仿真 corona渲染
下载PDF
Comprehensive and deep profiling of the plasma proteome with protein corona on zeolite NaY
7
作者 Congcong Ma Yanwei Li +10 位作者 Jie Li Lei Song Liangyu Chen Na Zhao Xueping Li Ning Chen Lixia Long Jin Zhao Xin Hou Li Ren Xubo Yuan 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2023年第5期503-513,共11页
Proteomic characterization of plasma is critical for the development of novel pharmacodynamic biomarkers.However,the vast dynamic range renders the profiling of proteomes extremely challenging.Here,we synthesized zeol... Proteomic characterization of plasma is critical for the development of novel pharmacodynamic biomarkers.However,the vast dynamic range renders the profiling of proteomes extremely challenging.Here,we synthesized zeolite NaY and developed a simple and rapid method to achieve comprehensive and deep profiling of the plasma proteome using the plasma protein corona formed on zeolite NaY.Specifically,zeolite NaY and plasma were co-incubated to form plasma protein corona on zeolite NaY(NaY-PPC),followed by conventional protein identification using liquid chromatography-tandem mass spectrometry.NaY was able to significantly enhance the detection of low-abundance plasma proteins,minimizing the“masking”effect caused by high-abundance proteins.The relative abundance of middleand low-abundance proteins increased substantially from 2.54%to 54.41%,and the top 20 highabundance proteins decreased from 83.63%to 25.77%.Notably,our method can quantify approximately 4000 plasma proteins with sensitivity up to pg/mL,compared to only about 600 proteins identified from untreated plasma samples.A pilot study based on plasma samples from 30 lung adenocarcinoma patients and 15 healthy subjects demonstrated that our method could successfully distinguish between healthy and disease states.In summary,this work provides an advantageous tool for the exploration of plasma proteomics and its translational applications. 展开更多
关键词 NAY Plasma proteomics Protein corona Low-abundance proteins
下载PDF
Study on the interaction mechanism of double-blade corona discharge with a large discharge gap
8
作者 李丁晨 李传 +4 位作者 李家玮 杨文迪 肖梦涵 张明 于克训 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第4期101-110,共10页
Multi-source corona discharge is a commonly used method to generate more charged particles,but the interaction mechanism between multiple discharge sources,which largely determines the overall discharge effect,has sti... Multi-source corona discharge is a commonly used method to generate more charged particles,but the interaction mechanism between multiple discharge sources,which largely determines the overall discharge effect,has still not been studied much.In this work,a large-space hybrid model based on a hydrodynamic model and ion-transport model is adopted to study the interaction mechanism between discharge sources.Specifically,the effects of the number of electrodes,voltage level,and electrode spacing on the discharge characteristics are studied by taking a double-blade electrode as an example.The calculation results show that,when multiple discharge electrodes operate simultaneously,the superimposed electric field includes multiple components from the electrodes,making the ion distribution and current different from that under a single-blade electrode.The larger the distance between discharge electrodes,the weaker the interaction.When the electrode spacing d is larger than 4 cm,the interaction can be ignored.The results can guide the design of large discharge gap array electrodes to achieve efficient discharge. 展开更多
关键词 non-equilibrium plasma corona discharge double-blade electrode interaction numerical simulation
下载PDF
Improving plasma sterilization by constructing a plasma photocatalytic system with a needle array corona discharge and Au plasmonic nanocatalyst
9
作者 朱斌 李其玮 +3 位作者 高亚楠 闫妍 朱益民 徐力 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第1期111-119,共9页
Efficient sterilization by a plasma photocatalytic system(PPS)requires strong synergy between plasma and photocatalyst to inactivate microorganisms while suppressing the formation of secondary pollutants.Here,we repor... Efficient sterilization by a plasma photocatalytic system(PPS)requires strong synergy between plasma and photocatalyst to inactivate microorganisms while suppressing the formation of secondary pollutants.Here,we report that a PPS constructed from a needle array corona discharge and Au/TiO2plasmonic nanocatalyst could remarkably improve the sterilization of Escherichia coli(E.coli)and alleviate formation of the discharge pollutant O3.At 6 kV,the combination of corona discharge and Au/TiO2achieves sterilization efficiency of 100%within an exposure time of 5 min.At 5 kV and an exposure time of 8 min,the presence of Au/TiO2improves sterilization efficiency of the corona discharge from 73%to 91%and reduces the O3concentration from 0.38 to 0.04 ppm,whereas the presence of TiO2reduces the sterilization efficiency and O3concentration to 66%and 0.17 ppm,respectively.The Au/TiO2in the PPS enables a uniform corona discharge,enhances the interaction between plasma,E.coli and nanocatalysts,and suppresses the formation of O3.Further,the Au/TiO2can be excited by ultraviolet-visible light emitted from the plasma to generate electron-hole pairs,and thus contributes to the formation of reactive radicals and the oxidative inactivation of E.coli.The PPS constructed from a needle array corona discharge and Au-based plasmonic nanocatalyst provides a promising approach for developing high-efficiency sterilization techniques. 展开更多
关键词 plasma photocatalysis STERILIZATION corona discharge Au/TiO2 nanocatalyst synergetic effect
下载PDF
Multi-point discharge model: study on corona discharge of double-ended needle in large space
10
作者 李丁晨 李家玮 +5 位作者 李传 张明 王鹏宇 刘志 杨勇 于克训 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第3期62-69,共8页
Corona discharge, as a common means to obtain non-equilibrium plasma, can generally obtain high-concentration plasma by increasing discharge points to meet production needs. However,the existing numerical simulation m... Corona discharge, as a common means to obtain non-equilibrium plasma, can generally obtain high-concentration plasma by increasing discharge points to meet production needs. However,the existing numerical simulation models used to study multi-point corona discharge are all calculations of small-scale space models, which cannot obtain the distribution characteristics of plasma in large space. Based on our previous research, this paper proposes a hybrid model for studying the distribution of multi-point discharge plasma in large-scale spaces, which divides the computational domain and computes separately with the hydrodynamic model and the ion mobility model. The simulation results are verified by a needle–ball electrode device. Firstly, the electric field distribution and plasma distribution of the needle electrodes with single tip and double tips are compared and discussed. Secondly, the plasma distribution of the needle electrode with the double tip at different voltages is investigated. Both computational and experimental results indicate that the charged particle concentration and current of the needle electrode with double tips are both twice as high as those of the needle electrode with a single tip. This model can extend the computational area of the multi-point corona discharge finite element model to the sub-meter(25 cm) or meter level, which provides an effective means to study the plasma distribution generated by multiple discharge points in large-scale space. 展开更多
关键词 corona discharge numerical simulation multi-point discharge large space double needle tip electrode
下载PDF
Simulation analysis on microscopic discharge characteristics of the bipolar corona of a floating conductor
11
作者 杨冬阳 陈坚 +2 位作者 段泽民 肖登明 金之俭 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第8期54-73,共20页
A floating conductor exhibits a bipolar corona phenomenon with microscopic discharge characteristics that are still unclear.In this study,a plasma simulation model of the bipolar corona with 108 chemical reaction equa... A floating conductor exhibits a bipolar corona phenomenon with microscopic discharge characteristics that are still unclear.In this study,a plasma simulation model of the bipolar corona with 108 chemical reaction equations is established by combining hydrodynamics and plasma chemical reactions.The evolution characteristics of electrons,positive ions,negative ions and neutral particles,as well as the distribution characteristics of space charges are analyzed,and the evolutionary flow of microscopic particles is summarized.The results indicate that the positive end of the bipolar corona initiates discharge before the negative end,but the plasma chemistry at the negative end is more vigorous.The electron generation rate can reach 1240 mol(m^(3) s)^(-1),and the dissipation rate can reach 34 mol(m^(3) s)^(-1).The positive ion swarm is dominated by O_(4)^(+),and the maximum generation rate can reach 440 mol((m^(3) s)^(-1).The negative ion swarm is mainly O_(2) and O_(4).The O_(2) content is approximately 1.5-3 times that of O_(4),and the maximum reaction rate can reach 51 mol(m^(3) s)^(-1).The final destination of neutral particles is an accumulation in the form of O_(3) and NO,and the amount of O3 produced is approximately 4-6 times that of NO.The positive end of the bipolar corona is dominated by positive space charges,which continue to develop and spread outwards in the form of a pulse wave.The negative end exhibits a space charge distribution structure of concentrated positive charges and diffused negative charges.The validity of the microscopic simulation analysis is verified by the macroscopic discharge phenomenon. 展开更多
关键词 bipolar corona evolution process floating conductor microscopic discharge characteristics space charge distribution
下载PDF
Extraction and Analysis of Coronal High-temperature Components Based on Outlier Detection
12
作者 Li-Yan Sun Kai-Fan Ji +1 位作者 Jun-Chao Hong Hui Liu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第6期143-152,共10页
The extraction of high-temperature regions in active regions(ARs)is an important means to help understand the mechanism of coronal heating.The important observational means of high-temperature radiation in ARs is the ... The extraction of high-temperature regions in active regions(ARs)is an important means to help understand the mechanism of coronal heating.The important observational means of high-temperature radiation in ARs is the main emission line of Fe XVⅢin the 94?of the Atmospheric Imaging Assembly.However,the diagnostic algorithms for Fe XVⅢ,including the differential emission measure(DEM)and linear diagnostics proposed by Del based on the DEM,have been greatly limited for a long time,and the results obtained are different from the predictions.In this paper,we use the outlier detection method to establish the nonlinear correlation between 94?and 171,193,211?based on the former researches by others.A neural network based on 171,193,211?is constructed to replace the low-temperature emission lines in the ARs of 94?.The predicted results are regarded as the low-temperature components of 94?,and then the predicted results are subtracted from 94?to obtain the outlier component of 94?,or Fe XVⅢ.Then,the outlier components obtained by neural network are compared with the Fe XVⅢobtained by DEM and Del's method,and a high similarity is found,which proves the reliability of neural network to obtain the high-temperature components of ARs,but there are still many differences.In order to analyze the differences between the Fe XVⅢobtained by the three methods,we subtract the Fe XVⅢobtained by the DEM and Del's method from the Fe XVⅢobtained by the neural network to obtain the residual value,and compare it with the results of Fe XIV in the temperature range of 6.1-6.45 MK.It is found that there is a great similarity,which also shows that the Fe XVⅢobtained by DEM and Del's method still has a large low-temperature component dominated by Fe XIV,and the Fe XVⅢobtained by neural network is relatively pure. 展开更多
关键词 Sun:corona Sun:activity methods:statistical methods:data analysis techniques:image processing
下载PDF
A network pharmacology approach to explore the mechanism of action of Yiqi Fumai lyophilized injection in the treatment of novel coronavirus disease
13
作者 Yan Zhou Lei Fan +11 位作者 Du-Hong Xie Xiao-Ying Han Bo-Xuan Zhao Yi Zhang De-Kun Li Ai-Chun Ju Hai-Xia Ji Ou Qiao Xin-Yu Zhang Wen-Zhe Wang Chang-Xiao Liu Wen-Yuan Gao 《Traditional Medicine Research》 2023年第3期1-9,共9页
Background:Shengmai decoction,which has been included in the diagnosis and treatment of coronavirus disease 2019(COVID-19),is effective in the early treatment of patients with severe COVID-19.Yiqi Fumai lyophilized in... Background:Shengmai decoction,which has been included in the diagnosis and treatment of coronavirus disease 2019(COVID-19),is effective in the early treatment of patients with severe COVID-19.Yiqi Fumai lyophilized injection(YQFM)is a modern Chinese medicine preparation of the Shengmai decoction.The mechanism of its intervention at the molecular level in the severe stage of COVID-19 remains unclear.Therefore,it is necessary to investigate the mechanism of YQFM in the treatment of patients with severe COVID-19.Methods:The corresponding target genes of the main active ingredients in YQFM and COVID-19 were obtained by using multiple databases and literature retrieval.A protein-protein interaction network was constructed,and enrichment analysis of the target was performed using Cytoscape 3.8.1.Lastly,the docking of all the identified compounds with angiotensin-converting enzyme II was confirmed by applying molecular docking technology.Results:YQFM has anti-inflammatory effects on RAW267.4 macrophages.The main active compounds of YQFM are all effective anti-inflammatory agents,and these active compounds also show beneficial physiological functions,such as anti-oxidation,anti-bacterial,and anticancer activities.Gene Ontology analysis showed enrichment in the following pathways:lipopolysaccharides,interleukins,NF-kappa B,interleukin-2 and others,revealing that YQFM may play a role in the treatment of patients with severe COVID-19 through these pathways.Conclusion:YQFM has multicomponent and multitarget characteristics,and it could reduce lung injury by inhibiting inflammatory reactions,promoting antiviral activities,and regulating immunity,among other functions,to treat patients with severe COVID-19. 展开更多
关键词 network pharmacology novel corona virus traditional Chinese medicine natural compounds INFLAMMATION
下载PDF
The current pulses characteristics of the negative corona discharge in SF_(6)/CF_(4)mixtures
14
作者 高青青 王小华 +4 位作者 Kazimierz ADAMIAK 杨爱军 刘定新 纽春萍 张嘉伟 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第2期119-130,共12页
This paper presents the results of numerical investigation of the current pulses characteristics in SF_(6)/CF_(4)mixtures for the negative point-plane corona discharge.The pressure and the temperature of gas mixtures ... This paper presents the results of numerical investigation of the current pulses characteristics in SF_(6)/CF_(4)mixtures for the negative point-plane corona discharge.The pressure and the temperature of gas mixtures are 0.4 MPa and 300 K,respectively.The CF_(4)content varies from20%to 80%.The 2D axisymmetric geometry with point-plane electrodes is investigated,and the three drift-diffusion equations are solved to predict the characteristics of the negative corona discharge.In addition,Poisson’s equation is coupled with the above three continuity equations to calculate the electric field.In order to calculate the electron impact coefficients,including the Townsend ionization and attachment coefficients,as well as the mobilities and diffusion coefficients for electrons,the two-term Boltzmann equation is solved.The characteristics of three ionic species at five stages of the first current pulse in 60%SF_(6)-40%CF_(4)and20%SF_(6)-80%CF_(4)mixtures are selected to discuss the development mechanism of current pulses.Moreover,the reduced electric field strengths at the corresponding time instants are presented to help understand the discharge process.The current waveform and the total number of three species are compared in all the cases to analyze the effects of the CF_(4)content on the discharge.The reduced electric field strength is also helpful in understanding the effects of CF_(4)content.When the CF_(4)content increases to 80%,the discharge is more intensive and the pulse frequency also increases. 展开更多
关键词 SF_(6)/CF_(4)mixtures negative corona discharge current pulses
下载PDF
Long-term corona behaviour and performance enhancing mechanism of SiC/epoxy nanocomposite in SF6 gas environment
15
作者 王靖瑞 李庆民 +4 位作者 公衍峰 侯启鑫 刘衡 王健 任瀚文 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第3期104-116,共13页
Surface coating technology is an effective way to solve the interface insulation problem of DC GIS/GIL basin insulators, but the performance of the coating will change greatly, and the insulation strength will be comp... Surface coating technology is an effective way to solve the interface insulation problem of DC GIS/GIL basin insulators, but the performance of the coating will change greatly, and the insulation strength will be completely lost, after long-term use in the extreme conditions of corona erosion. In this research, the multi-needle-plate electrode platform was constructed to explore the long-term use performance of Si C-doped nanocomposite exposed to corona discharge in SF6gas. Samples with a high Si C content have advantages in maintaining physical and chemical properties such as elemental composition, erosion depth, surface roughness and mass loss. The nanocomposite doped with 6 wt.% Si C has prominent surface insulation strength after long term exposure to corona, and the others are close to losing, or have completely lost,their insulating properties. Furthermore, the degradation mechanism of physicochemical properties of composite exposed to corona discharge was investigated with the proposed Reax FF MD model of energetic particles from SF6decomposition bombarding the epoxy surface. The reaction process of SF particles and F particles with the cross-linked epoxy resin, and the Si C nanoparticles providing shelter to the surrounding polymer and mitigating their suffering direct bombardment, have been established. The damage propagation depth, mass loss and surface roughness change of nanocomposite material bombarded by SF6decomposition products is reproduced in this simulation. Finally, the deterioration mechanism of insulation properties for the Si C-doped composite was elucidated with DFT analysis. The band gap of the molecule containing S drops directly from the initial 7.785 e V to 1.875 e V, which causes the deterioration of surface electric properties. 展开更多
关键词 corona discharge in SF6 SiC doped nanocomposite epoxy resin ReaxFF MD DFT(Some figures may appear in colour only in the online journal)
下载PDF
On the Relation Between Coronal Green Line Brightness and Magnetic Fields Intensity 被引量:2
16
作者 Xue-Fei Zhang Yu Liu +4 位作者 Ming-Yu Zhao Teng-Fei Song Jing-Xing Wang Xiao-Bo Li Zi-Han Li 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2022年第7期128-138,共11页
Two-dimensional(2 D) solar coronal magnetogram is difficult to be measured directly until now.From the previous knowledge,a general relation has been noticed that the brighter green-line brightness for corona,the high... Two-dimensional(2 D) solar coronal magnetogram is difficult to be measured directly until now.From the previous knowledge,a general relation has been noticed that the brighter green-line brightness for corona,the higher coronal magnetic field intensity may correspond to.To try to further reveal the relationship between coronal green line brightness and magnetic field intensity,we use the 2 D coronal images observed by Yunnan Observatories Greenline Imaging System(YOGIS) of the 10 cm Lijiang coronagraph and the coronal magnetic field maps calculated from the current-free extrapolations with the photospheric magnetograms taken by Helioseismic and Magnetic Imager(HMI) on board the Solar Dynamics Observatory(SDO) spacecraft.In our analysis,we identified the coronal loop structures and construct two-dimensional maps of the corresponding magnetic field intensity in the plane of the sky(POS) above the limb.We derive the correlation coefficients between the coronal brightness and the magnetic field intensity for different heights of coronal layers.We further use a linear combination of a Gaussian and a quadratic profile to fit the correlation coefficients distribution,finding a largest correlation coefficient of 0.82 near 1.1 R(solar radii) where is almost the top of the closed loop system.For the small closed loop system identified,the correlation coefficient distributions crossing and covering the loop are calculated.We also investigate the correlation with extended heliocentric latitude zones and long period of one whole Carrington Rotation,finding again that the maximum correlation coefficient occurs at the same height.It is the first time for us to find that the correlation coefficients are high(all are larger than 0.8) at the loop-tops and showing poor correlation coefficients with some fluctuations near the feet of the coronal loops.Our findings indicate that,for the heating of the low-latitude closed loops,both DC(dissipation of currents) and AC(dissipation of Alfvén and magnetosonic waves) mechanisms should act simultaneously on the whole closed loop system while the DC mechanisms dominate in the loop-top regions.Therefore,in the distributions of the correlation coefficients with different heights of coronal layers,for both large-and small-scale latitude ranges,the coefficients can reach their maximum values at the same coronal height of 1.1 R,which may indicate the particular importance of the height of closed loops for studying the coupling of the local emission mechanism and the coronal magnetic fields,which maybe helpful for studying the origin of the low-speed solar wind. 展开更多
关键词 Sun:magnetic fields Sun:corona Stars:coronae Sun:activity Sun:atmosphere Sun:coronal mass ejections(CMEs) Sun:fundamental parameters Sun:heliosphere Sun:UV radiation
下载PDF
基于Corona和Spot-5影像的图们江下游敬信湿地变化研究 被引量:13
17
作者 刘志锋 朱卫红 +3 位作者 南颖 森本幸裕 王琪 赵洋 《湿地科学》 CSCD 2009年第3期237-242,共6页
采用1964年的Corona影像和2004年的Spot-5影像作为数据源,结合"3S"技术与实地考查资料,对图们江下游敬信湿地信息进行了提取与分类,分别得到了研究区1964年和2004年的湿地分类图;通过建立研究区的湿地动态变化特征模型,从各... 采用1964年的Corona影像和2004年的Spot-5影像作为数据源,结合"3S"技术与实地考查资料,对图们江下游敬信湿地信息进行了提取与分类,分别得到了研究区1964年和2004年的湿地分类图;通过建立研究区的湿地动态变化特征模型,从各类型湿地的面积变化和斑块变化两个角度,研究敬信湿地的变化特征及其成因。结果表明,研究区各类型湿地在气候变化、人类活动等因素的影响下发生了不同程度的变化,与1964年相比,2004年研究区人工湿地面积增加了16.923km2,这主要是修建龙山水库以及水田、养鱼池和孵化池面积大量增加所致;而自然湿地受到严重破坏,面积减少了17.33km2,河流和沼泽面积都减少了50%以上。研究区河流的斑块数急剧减少,沼泽湿地的斑块破碎化程度加剧,河流和沼泽湿地的斑块分维值明显下降,大面积沼泽被开发成水田,这两种湿地的空间自我相似性逐渐变差。研究区部分湖泊被开发利用,人为束水使得水面面积扩大,当地居民为了发展经济,在湖泊中从事鱼类养殖以及用湖泊水进行农业灌溉等活动,研究区人类活动干扰日趋严重。 展开更多
关键词 敬信湿地 变化 图们江下游 corona影像 Spot-5影像
下载PDF
基于Corona和Spot影像的近40年黑土典型区侵蚀沟动态变化 被引量:35
18
作者 闫业超 张树文 岳书平 《资源科学》 CSSCI CSCD 北大核心 2006年第6期154-160,共7页
沟状侵蚀是我国东北黑土区一种比较常见的土壤侵蚀类型。当前国内外学者对侵蚀沟动态变化的研究多采用GPS或摄影测量的方法监测某些侵蚀沟的短期变化,由于缺少早期高分辨率的卫星影像,对于较大时空尺度上侵蚀沟分布格局变化的研究很少... 沟状侵蚀是我国东北黑土区一种比较常见的土壤侵蚀类型。当前国内外学者对侵蚀沟动态变化的研究多采用GPS或摄影测量的方法监测某些侵蚀沟的短期变化,由于缺少早期高分辨率的卫星影像,对于较大时空尺度上侵蚀沟分布格局变化的研究很少报道。本文选择克拜东部地区作为典型区,以1965年的美国高分辨率侦察卫星Corona影像和2005年的Spot-5卫星影像为主要数据源,结合野外实地调查,建立了黑土区侵蚀沟的遥感解译标志,阐述了不同类型侵蚀沟的遥感影像特征,通过对遥感影像的人机交互解译,获取了克拜东部地区1965年和2005年两个时期的侵蚀沟分布图,在此基础上,探讨了1965年以来克拜东部黑土区侵蚀沟分布的格局变化和区域差异。研究结果表明:近40年来克拜东部侵蚀沟密度高值区范围不断扩大,且呈集中连片分布趋势;沿通垦河分水岭两侧受地貌发育自然过程的影响,侵蚀沟密度变化存在明显的东西差异;土地利用方式的转变是促成侵蚀沟形成的重要因素,特别是林地向耕地和草地的转化过程中,侵蚀沟密度迅速增加。 展开更多
关键词 黑土 侵蚀沟 克拜地区 corona影像 动态变化
下载PDF
Corona Mortis血管解剖学研究及其临床意义 被引量:7
19
作者 洪华兴 陈海啸 +2 位作者 洪正华 潘志军 林列 《中国骨伤》 CAS 2006年第6期355-357,共3页
目的:探讨闭孔血管和髂外血管在腹股沟区的分支,为减少髂腹股沟入路术中出血提供解剖学基础。方法:对25具新鲜中国成人尸体标本共50侧半骨盆进行解剖学研究,观测闭孔血管和髂外血管在腹股沟区的分支及其吻合支(CoronaMortis血管)的大小... 目的:探讨闭孔血管和髂外血管在腹股沟区的分支,为减少髂腹股沟入路术中出血提供解剖学基础。方法:对25具新鲜中国成人尸体标本共50侧半骨盆进行解剖学研究,观测闭孔血管和髂外血管在腹股沟区的分支及其吻合支(CoronaMortis血管)的大小、出现率、吻合血管行径和吻合血管至耻骨联合的距离。结果:72%(36侧)耻骨上支表面至少存在1条血管吻合支,其中28%(14侧)存在2条或3条血管吻合支,24%(12侧)同时存在动脉吻合支和静脉吻合支。耻骨上支表面的血管吻合支平均直径2.6mm(2.0~4.2mm)。血管吻合支紧贴耻骨上支或髂耻隆起,几乎垂直地下行于髋臼窝壁或耻骨支后方,经闭膜管出盆腔,血管吻合支与耻骨联合的平均距离52mm(38~68mm)。在此区域手术以及髋臼或骨盆前环骨折极易损伤CoronaMortis血管。结论:闭孔血管和髂外血管的吻合支较粗,出现率高,位于耻骨上支表面。髂腹股沟手术入路应特别注意CoronaMortis血管的存在。 展开更多
关键词 解剖学 corona Mortis血管 髂骨 血管
下载PDF
一些与圈图构成的Corona图的b-染色 被引量:5
20
作者 吕闯 王科伦 +1 位作者 张若东 潘淑霞 《兰州理工大学学报》 CAS 北大核心 2016年第6期151-155,共5页
图G的一个(k)b-染色是一个正常k染色,且满足在每一个色类中至少存在一个顶点,使得该顶点与其他每个色类中至少一个顶点是邻接的.图G的b-染色数用b(G)来表示,b(G)为最大的正整数k,且用k种颜色能够对G进行b-染色.对于任意的k:χ(G)≤k≤b(... 图G的一个(k)b-染色是一个正常k染色,且满足在每一个色类中至少存在一个顶点,使得该顶点与其他每个色类中至少一个顶点是邻接的.图G的b-染色数用b(G)来表示,b(G)为最大的正整数k,且用k种颜色能够对G进行b-染色.对于任意的k:χ(G)≤k≤b(G),若用k种颜色能对图G进行b-染色,称图G是b-连续.通过设计具体b-染色方案,研究了Corona图CnoPm、CnoK1,m以及CnoWm+1的m-度与b-染色数,且证明这些图都是b-连续的. 展开更多
关键词 b-染色 b-染色数 b-连续 m-度 corona
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部