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
Electromagnetic Ion Beam Instability in the Solar Corona
2
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
Observation of Standing Slow Magneto-acoustic Waves in a Flaring Active Region Corona Loop
3
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
4
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
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
A network pharmacology approach to explore the mechanism of action of Yiqi Fumai lyophilized injection in the treatment of novel coronavirus disease
12
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
13
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
Extraction and Analysis of Coronal High-temperature Components Based on Outlier Detection
14
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
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
体质贴联合八段锦功法治疗气虚血瘀质新型冠状病毒感染恢复期患者的临床研究 被引量:1
16
作者 周胜元 王凯 +5 位作者 付鲲 张硕 倪道艳 孙小茁 刘欢 雒明池 《天津中医药》 CAS 2024年第4期427-431,共5页
[目的]观察气虚血瘀体质贴(简称体质贴)联合八段锦功法对气虚血瘀体质的新型冠状病毒感染恢复期患者的临床疗效。[方法]符合入选标准的43例新型冠状病毒感染恢复期患者分为试验组(21例)和对照组(22例)两组均在八段锦功法的基础上予体质... [目的]观察气虚血瘀体质贴(简称体质贴)联合八段锦功法对气虚血瘀体质的新型冠状病毒感染恢复期患者的临床疗效。[方法]符合入选标准的43例新型冠状病毒感染恢复期患者分为试验组(21例)和对照组(22例)两组均在八段锦功法的基础上予体质贴辅助治疗,治疗12周后,观察两组患者治疗前后在中医症状积分量表、改良英国医学研究委员会呼吸困难量表(mMRC)、Borg自觉疲劳量表和匹兹堡睡眠问卷(PSQI)的评分改善情况。[结果]治疗12周后,与治疗前相比,试验组中医症状总积分明显降低(P<0.05);组间比较显示试验组总积分明显低于对照组(P<0.05)。在改善单项症状积分方面,两组与各自治疗前相比,试验组在改善肌肉疲劳、气短、胸闷、干咳的方面积分明显降低(P<0.05),对照组在改善肌肉疲劳、自汗盗汗方面的积分明显降低(P<0.05)。组间比较显示,试验组在改善肌肉疲劳、气短、心悸、胸闷、干咳上的积分较对照组积分明显降低(P<0.05)。mMRC量表评分结果显示,两组患者与治疗前相比,呼吸症状评分无明显变化(P>0.05)。Borg量表和PSQI量表结果显示,与治疗前相比,两组患者症状积分均明显下降(P<0.05),但组间比较差异无统计学意义(P>0.05)。[结论]体质贴联合八段锦康复治疗对气虚血瘀质新型冠状病毒感染恢复期患者的中医症状有改善作用,尤对肌肉疲劳、气短、心悸、胸闷、干咳改善明显,同时可以减轻患者疲劳,改善患者睡眠质量。 展开更多
关键词 新型冠状病毒感染 康复 气虚血瘀 体质 量表
下载PDF
SiC改性提升聚酰亚胺薄膜直流耐电晕性能的机理
17
作者 王健 熊沛琪 +3 位作者 侯程志 张淑敏 刘继奎 李庆民 《高电压技术》 EI CAS CSCD 北大核心 2024年第4期1655-1663,共9页
传统聚酰亚胺(PI)薄膜应用到更高电压等级设备中,易产生电晕放电甚至绝缘失效。为提升聚酰亚胺薄膜耐电晕能力,实验采取碳化硅(SiC)作为增强相对PI基体相进行改性,探究SiC改性对复合薄膜耐电晕特性的影响机理。实验结果表明,随着SiC含... 传统聚酰亚胺(PI)薄膜应用到更高电压等级设备中,易产生电晕放电甚至绝缘失效。为提升聚酰亚胺薄膜耐电晕能力,实验采取碳化硅(SiC)作为增强相对PI基体相进行改性,探究SiC改性对复合薄膜耐电晕特性的影响机理。实验结果表明,随着SiC含量增加,SiC/PI复合薄膜出现非线性电导特性并逐渐增强,其同步提升的浅深陷阱密度比与载流子迁移率促进了表面电荷消散速率的增加。同时,SiC提升了15 kV直流电压下薄膜的沿面闪络和击穿时间,其中质量分数25%SiC/PI复合薄膜较纯PI膜分别提升了416.28%和298.39%。这是因为增强的非线性电导率和表面电荷消散速率,有利于空间和表面电荷运输,减少电场畸变,从而提升复合薄膜的耐电晕能力。对电晕损伤薄膜的无损区、圆状白斑区和白色堆积区进行形貌观测,发现SiC颗粒会在等离子体碰撞下形成放电阻挡层,有效减少电晕对基体相的侵蚀,延长了复合薄膜的耐电晕时间。最后发现质量分数15%SiC/PI复合薄膜为综合耐电晕与力学特性下的最优选择。 展开更多
关键词 聚酰亚胺薄膜 耐电晕 碳化硅 电荷 电晕损伤 力学特性
下载PDF
新冠病毒疫苗接种对肺功能的保护作用及早期新冠肺炎的影响
18
作者 许诺 沈志文 +2 位作者 杨燕平 陈智鸿 李丽 《复旦学报(医学版)》 CAS CSCD 北大核心 2024年第4期574-579,593,共7页
目的探讨新冠病毒疫苗接种对新冠病毒感染患者肺功能的影响以及新冠病毒疫苗接种对感染患者的保护作用。方法选取2023年1月7日至2023年2月7日期间在复旦大学附属中山医院完成肺功能检查的1178例门诊及住院新冠感染患者,按照是否患有新... 目的探讨新冠病毒疫苗接种对新冠病毒感染患者肺功能的影响以及新冠病毒疫苗接种对感染患者的保护作用。方法选取2023年1月7日至2023年2月7日期间在复旦大学附属中山医院完成肺功能检查的1178例门诊及住院新冠感染患者,按照是否患有新冠肺炎分为两组,完成“新冠感染症状及肺功能相关调查表”,同时采集患者疫苗接种情况、临床症状、肺通气功能、弥散功能和呼出气一氧化氮结果(fractional exhaled nitric oxide,FeNO)等临床资料,通过χ^(2)检验、Pearson相关性分析、单因素及多因素Logistic回归模型等方法分析接种和未接种新冠病毒疫苗患者肺功能的差异,并验证新冠病毒疫苗对新冠肺炎、新冠感染相关症状的保护作用。结果未接种新冠病毒疫苗的新冠感染患者通气及弥散肺功能较接种患者下降明显(P<0.05)。未接种过新冠病毒疫苗、有既往慢性病史的患者更容易发生新冠肺炎,二针/三针疫苗接种可以减少新冠肺炎的发生率(P<0.05),而接种一针无明显保护作用;既往慢性病病史患者,如发生新冠感染,容易出现严重症状,而接种新冠病毒疫苗可以减轻包括慢性病患者在内的新冠相关严重症状。结论新冠病毒感染可以造成患者肺通气及弥散功能下降,二针/三针新冠病毒疫苗的接种可能减轻新冠病毒感染对肺功能的损伤,减少新冠肺炎及严重症状的发生,完整的新冠病毒疫苗接种可能具有保护作用。 展开更多
关键词 新型冠状病毒肺炎(COVID-19) 疫苗接种 肺功能
下载PDF
重型新型冠状病毒肺炎患者发生急性肾损伤的危险因素及其预测价值
19
作者 牛丹 张怡 董道然 《临床肾脏病杂志》 2024年第9期720-727,共8页
目的筛选重型新型冠状病毒肺炎(coronavirus disease 2019,COVID-19)患者发生急性肾损伤(acute kidney injury,AKI)的危险因素,构建预测模型,并探讨其预测价值。方法回顾性分析2022年12月1日至2023年7月1日在陕西省人民医院重症医学科... 目的筛选重型新型冠状病毒肺炎(coronavirus disease 2019,COVID-19)患者发生急性肾损伤(acute kidney injury,AKI)的危险因素,构建预测模型,并探讨其预测价值。方法回顾性分析2022年12月1日至2023年7月1日在陕西省人民医院重症医学科确诊为重型COVID-19的150例患者的临床资料,根据是否发生AKI分为AKI组(54例)和非AKI组(96例),比较两组患者的临床资料,采用多因素Logistic回归分析筛选重型COVID-19患者发生AKI的危险因素,构建预测模型,并采用受试者工作特征(receiver operating chatacteristic,ROC)曲线分析该模型的预测价值。结果AKI组患者的年龄为74.50(63.00,81.50)岁,明显低于非AKI组75.00(70.00,83.00)岁;AKI组合并慢性阻塞性肺疾病比例(1.85%)和接受经鼻高流量氧疗治疗比例(38.89%),均明显低于非AKI组(13.54%和58.33%)(均P<0.05)。AKI组急性生理与慢性健康评分Ⅱ[20.50(15.00,25.00)]和序贯器官衰竭评分(sequential organ failure assessment,SOFA)[8.00(6.00,10.00)]均明显高于非AKI组[16.00(13.00,18.25)和5.00(4.00,6.00)];AKI组患者合并细菌感染比例(61.11%)和接受有创通气治疗比例(57.41%)均显著高于非AKI组(40.62%和25.00%)(均P<0.05)。AKI组患者氧合指数[109.55(75.99,149.50)mmHg,1 mm Hg=0.133 kPa]和血红蛋白[(109.61±24.46)g/L]均显著低于非AKI组[134.50(105.36,156.57)mmHg和(121.24±21.77)g/L];AKI组的N端脑利钠肽[3148.28(446.42,13572.58)ng/L]、降钙素原[1480(560,8420)ng/L]、部分活化凝血活酶时间[39.80(34.42,45.32)s]和天冬氨酸氨基转移酶[38.00(21.00,66.50)U/L]均显著高于非AKI组[502.41(171.50,1703.00)ng/L、0.37(110,1040)ng/L、36.95(32.70,42.20)s、34.00(20.50,53.00)U/L],并且其血尿素氮[13.86(8.68,18.70)mmol/L]、血肌酐[177.00(90.30,375.00)μmol/L]和胱抑素C[2.67(1.77,4.08)mg/L]均显著高于非AKI组[7.31(5.51,9.67)mmol/L、62.95(51.75,78.10)μmol/L、1.34(1.10,1.61)mg/L](均P<0.05)。多因素Logistic回归分析结果显示,SOFA评分高、合并细菌感染和血肌酐高均是重型COVID-19患者发生AKI的独立危险因素(均P<0.05)。以上述危险因素构建预测模型,并进行ROC曲线分析,结果显示该模型预测AKI发生的ROC曲线下面积为0.916(95%CI:0.8687~0.9633),敏感度为77.36%,特异度为92.63%。结论血肌酐高、SOFA评分高、合并细菌感染是重型COVID-19发生AKI的独立危险因素。由上述危险因素构建的预测模型对重型COVID-19发生AKI有一定的预测价值。 展开更多
关键词 新型冠状病毒肺炎 急性肾损伤 危险因素
下载PDF
针刺结合热敏灸治疗新冠后失眠临床观察 被引量:1
20
作者 尚艳杰 黄佳凝 《山西中医》 2024年第2期35-37,共3页
目的:观察针刺结合热敏灸治疗新冠后遗症失眠患者的临床疗效。方法:选择新冠后遗症失眠患者54例,随机分为两组各27例。对照组予头针结合常规针刺治疗,治疗组在对照组基础上予热敏灸治疗,观察两组睡眠质量及焦虑程度变化。结果:治疗组总... 目的:观察针刺结合热敏灸治疗新冠后遗症失眠患者的临床疗效。方法:选择新冠后遗症失眠患者54例,随机分为两组各27例。对照组予头针结合常规针刺治疗,治疗组在对照组基础上予热敏灸治疗,观察两组睡眠质量及焦虑程度变化。结果:治疗组总有效率为88.89%,对照组总有效率为62.96%,两组比较有统计学差异(P<0.05)。治疗后,两组匹兹堡睡眠质量指数量表(PSQI)总分及各项评分均低于治疗前,且治疗组较对照组低,差异有统计学意义(P<0.05);两组焦虑自评量表(SAS)各项评分均低于治疗前,且治疗组较对照组低(P<0.05)。结论:采用针刺结合热敏灸治疗新冠后遗症失眠患者可显著缓解临床症状,改善患者睡眠质量,减轻患者焦虑程度。 展开更多
关键词 失眠 新冠肺炎 针刺 热敏灸
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部