Stage Of Discharge Research Articles

A Defect Spinel Cathode Material for Long-Life and High-Energy-Density Magnesium Rechargeable Batteries

Magnesium rechargeable batteries (MRBs) have been a promising candidate for next-generation batteries due to the following reasons: (i) Mg can deposit without dendritic formation, enabling us to safely use Mg metal itself as a high-capacity (2205 mAh/g) anode. (ii) The electrode potential of Mg (-2.4 V vs. SHE) is relatively low among metal anodes for multivalent batteries, which is attractive for achieving high cell voltage. (iii) Mg is an abundant and non-toxic element. The development of MRBs, however, has been hindered by the lack of high-performance cathode materials. The difficulty in the development of cathode materials is derived from the high charge density of divalent Mg2+ ion, which is almost twice that of monovalent Li+ ion since their ionic radii are similar. This leads to the high activation energies for Mg2+ diffusion in cathode materials by the strong electrostatic interaction with anions. High-temperature operation is a way to prevent the problem of the sluggish Mg2+ diffusion; thus, we have been developing high-potential spinel oxide cathode materials that can work at 150℃. We have found several promising cathode materials (e.g., MgCo2O4, ZnCo2O4) [1,2], but they show rapid capacity fading during battery cycling. Such stoichiometric spinel oxides coherently transform to the rocksalt structure accompanied by Mg insertion in the two-phase reaction [1]. Therefore, the cycle degradation can be attributed to the formation of the rocksalt phase on the surface of active material particles, which would impede the diffusion of Mg2+ ions and degrade the reversibility of structural change in discharge/charge.Very recently, we have proposed a strategy of utilizing defect spinel oxides, which contain cation deficiencies at the octahedral sites in the spinel structure, to suppress the structure transition into the densely packed rocksalt phase in the early stage of discharge (i.e., Mg insertion) [3]. We have chosen ZnMnO3 as a promising candidate for defect spinel-type cathode material in that Zn stabilizes the spinel structure [2] and Mn allows the valence change from tetravalent to divalent [1]. By the theoretical and experimental approach, we have confirmed that ZnMnO3 with cation deficiencies at the octahedral sites is stable, and Mg2+ ions are preferentially inserted into the cation-deficient sites at the potential of 2–3 V vs. Mg2+/Mg with keeping spinel-based structures. As a consequence, it has been demonstrated that ZnMnO3 cathode exhibits a long-term cyclability exceeding 100 cycles (see Figure 1), which is in strong contrast to the previous stoichiometric spinel oxides. In this presentation, we will show a general guideline for designing spinel cathode materials suitable for MRBs, and discuss the origin of the high performances of defect spinel ZnMnO3 in terms of element selection, structure modification, and phase-change behavior.

Simulations of the Formation of Nitrogen Oxides at the Cooling Stage of a Subthreshold Microwave Discharge in Air with Admixtures of Methane

Simulations of the Formation of Nitrogen Oxides at the Cooling Stage of a Subthreshold Microwave Discharge in Air with Admixtures of Methane

Influences on Discharge Partitioning on a Large River Delta: Case Study of the Mississippi‐Atchafalaya Diversion, 1926–1950

AbstractThe modern Mississippi River (M.R.) Delta is plumbed by the Mississippi and Atchafalaya rivers, setting water and sediment dispersal pathways for Earth’s fifth‐largest river system. The Atchafalaya River’s (A.R.) partial annexation of discharge from the M.R., particularly between 1926 and 1950, prompted warnings of a rapid river avulsion and the construction of the Old River Control Structure to regulate flow. Natural and anthropogenic causes of this discharge annexation are difficult to disentangle. Here, we develop and validate a hydrodynamic model of flow partitioning through the historic channel network. We then isolate how several key changes to the system affected discharge partitioning and stage at the A.R.‐M.R. diversion. Simulations show that erosion of the upper A.R. can account for 73% of the water discharge increase. Dredging in the lower A.R. between 1932 and 1950 can account for 35% of the water discharge increase, and was also an important control on shear stress distribution. The lower M.R. was slightly erosional during this period, and therefore hindered the A.R. discharge increase. Significant lacustrine delta deposition in A.R. had little effect on partitioning. These findings highlight the importance of A.R. enlargement processes on avulsion dynamics at this site. Given the essential nature of this river junction to the society, transportation, and commerce of the United States, improved attribution of discharge increases may lead to future management strategies that are broadly impactful.

AI in patient flow: applications of artificial intelligence to improve patient flow in NHS acute mental health inpatient units

IntroductionGrowing demand for mental health services, coupled with funding and resource limitations, creates an opportunity for novel technological solutions including artificial intelligence (AI). This study aims to identify issues in patient flow on mental health units and align them with potential AI solutions, ultimately devising a model for their integration at service level. MethodFollowing a narrative literature review and pilot interview, 20 semi-structured interviews were conducted with AI and mental health experts. Thematic analysis was then used to analyse and synthesise gathered data and construct an enhanced model. ResultsPredictive variables for length-of-stay and readmission rate are not consistent in the literature. There are, however, common themes in patient flow issues. An analysis identified several potential areas for AI-enhanced patient flow. Firstly, AI could improve patient flow by streamlining administrative tasks and optimising allocation of resources. Secondly, real-time data analytics systems could support clinician decision-making in triage, discharge, diagnosis and treatment stages. Finally, longer-term, development of solutions such as digital phenotyping could help transform mental health care to a more preventative, personalised model. ConclusionsRecommendations were formulated for NHS trusts open to adopting AI patient flow enhancements. Although AI offers many promising use-cases, greater collaborative investment and infrastructure are needed to deliver clinically validated improvements. Concerns around data-use, regulation and transparency remain, and hospitals must continue to balance guidelines with stakeholder priorities. Further research is needed to connect existing case studies and develop a framework for their evaluation.

Investigation on the products distribution, reaction pathway, and discharge mechanism of low‐pressure CO2 discharge by employing a 1D simulation model

AbstractMars has a special carbon dioxide environment. The surface and atmosphere of Mars contain a large amount of solid and gaseous carbon dioxide, which makes the in‐situ resource utilization of Martian carbon dioxide attract widespread attention. The conversion of carbon dioxide into fuel or high value‐added products through electrical discharge has become a research focus, in which numerical simulation is one of the important means to explain the experimental phenomenon and the mechanism. Therefore, a one‐dimensional fluid model was established in this paper to simulate the discharge and conversion of carbon dioxide under simulated Martian atmospheric pressure. The discharge mode, particle distribution, and discharge mechanism were studied by considering CO2 vibrational states and vibration relaxation reaction in the model. The results show that the discharge mode is glow discharge with an obvious cathode fall region, negative glow space, and positive column. The density of the four discharge products, C, O2, CO, and O, shows a step‐up trend, showing a significant cumulative effect, and the peak values appear near both electrodes. The density of vibrational states of CO2 molecule, which is highest in the neutral products, increases during the discharge stage and decreases after the discharge is extinguished. The temporal and spatial distribution of reaction rates shows that vibrational excitation, electronic excitation, and vibrational relaxation reactions dominate the loss and formation of CO2. The density of ground‐state CO2 decreases obviously in the discharge stage, and the minimum density appears near the instantaneous cathode. After the discharge is extinguished, the CO2 near the instantaneous cathode increases gradually.

Study on the polarity effect in an atmospheric pressure glow discharge driven by resonant power supply

In recent years, atmospheric pressure glow discharge has become an active research area for many scholars because of its broad industrial application prospects. However, much of the research is focused more on how to acquire this type of discharge or how to use it in some fields; there is a lack of clear and universally accepted theories. In this paper, we described the polarity effect in the process of atmospheric pressure glow discharge driven by a resonant power supply, from the standpoint of the differences in electric field direction in the pin-to-plate gap. We also discussed the characteristics of the discharge waveform, the characteristics of discharge images and the light-intensity distribution on the centerline of the discharge channel. Also studied were the polarity effect of unipolar discharge and the influence of different output-voltage amplitudes on the polarity effect. We found that both positive and negative discharges looked like a typical glow discharge. The voltage and current waveforms of unipolar discharge have a rapidly rising slope, and there is strong ionization near the anode. In the process of a unipolar discharge, there is an obvious γ discharge stage, and the α mode discharge has an obvious high-slope stage, whereas the slope of this process of a negative discharge is more gradual, and the polarity effects of positive and negative unipolar discharges become less and less obvious with the increase in the output-voltage amplitude of power supply.

Electron–neutral bremsstrahlung radiation fingerprints the initial stage of nanosecond discharge in liquid water

We postulate that basic radiative signatures observed during the initial phases of nanosecond discharge in liquid water can be attributed to the electron–neutral bremsstrahlung process. Principal characteristics of the radiation collected from developing luminous filaments consist of a sharp decrease in the emission intensity at the short-wavelength side of the spectra, followed by a maximum and subsequent decrease in intensity towards near-infrared wavelengths. All these radiative features can be attributed to the electron–neutral bremsstrahlung produced by a bell-like energy distribution of the electrons. Such an electron energy distribution function is coherent with the concept of electric field emission into electrostriction-induced nanovoids. The findings of this work help in elucidating the hitherto unclear mechanism(s) of plasma generation in liquid water.

Electrochemical Generation of Hydrated Zinc Vanadium Oxide with Boosted Intercalation Pseudocapacitive Storage for a High-Rate Flexible Zinc-Ion Battery.

With the surging development of flexible wearable and stretchable electronic devices, flexible energy-storage devices with excellent electrochemical properties are in great demand. Herein, a flexible Zn-ion battery comprised by hydrated zinc vanadium oxide/carbon cloth (ZnVOH/CC) as the cathode is developed, and it shows a high energy density, superior lifespan, and good safety. ZnVOH/CC is obtained by the in situ transformation of hydrated vanadium oxide/carbon cloth (VOH/CC) by an electrochemical method, and the intercalation pseudocapacitive reaction mechanism is discovered for ZnVOH/CC. The co-insertion/deinsertion of H+/Zn2+ is observed; the H+ insertion dominates in the initial discharge stage and the high-rate electrochemical process, while Zn2+ insertion dominates the following discharge stage and the low-rate electrochemical procedure. An ultrastable reversible capacity of 135 mAh g-1 at 20 A g-1 is obtained after 5000 cycles without capacity fading. Moreover, the as-assembled flexible zinc-ion battery can operate normally under rolled, folded, and punched conditions with superior safety. It is capable to deliver a high discharge capacity of 184 mAh g-1 at 10 A g-1 after 170 cycles. This work paves a new way for designing low-cost, safe, and quick-charging energy-storage devices for flexible electronics.

Study of the influence of discharge loop parameters on anode side on generation characteristics of metal plasma jet in a pulsed vacuum discharge

In a pulsed vacuum discharge, the ejection performance of a metal plasma jet can be effectively improved by preventing charged particles from moving to the anode. In this paper, the effects of resistance and capacitance on the anode side on the discharge characteristics and the generation characteristics of plasma jet are investigated. Results show that the existence of a resistor on the anode side can increase the anode potential, thereby preventing charged particles from entering the anode and promoting the ejection of charged particles along the axis of the insulating sleeve nozzle. The application of a capacitor on the anode side can not only absorb electrons at the initial stage of discharge, increasing the peak value of the cathode hump potential, but also prevent charged particles from moving to the anode, thereby improving the ejection performance of the plasma jet. In addition, the use of a larger resistance and a smaller capacitance can improve the blocking effect on charged particles and further improve the ejection performance of the plasma jet. Results of this study will provide a reference for the improvement of the ejection performance of plasma jets and their applications.

Understanding the Role of HDL during COVID-19 Infection

Background: Recently emerged COVID-19 pandemic has caused a large number of deaths with lacs of confirmed cases worldwide posturing a grim situation and severe threat to public health. There is an imperative necessity of analyzing emerging clinical and laboratory data of COVID-19 patients, which may contribute to elucidate the pathogenic mechanism and development of effective prevention and treatment countermeasures. Methods: Under this article, the emerging role of High-Density Lipoprotein (HDL) was analyzed by collecting recently published articles related to this field having clinical data of COVID-19 patients. Results: Based on the recently published reports of laboratory-confirmed COVID-19 infected hospitalized patients it was consistently observed that levels of HDL were low at the time of admission to hospital and remained relatively low during the disease course i.e., treatment, recovery, and discharge stage. It was also reported critically that levels of HDL in the patients, those did not survive, decreased continuously until death. Conclusion: These clinical reports of patients have risen the concern about probable infection and worsen the clinical outcome of a healthy person having a compromised level of HDL for COVID-19 infection. Eventually, these findings stated that there is a strong association of low HDL levels with a higher risk of COVID-19 infection and further severity of the illness. Proper attention is needed to understand the significance of altered quantity and quality of HDL in COVID-19 patients compared to healthy controls, so that appropriate therapies could be given at the right time to combat severity and mortality due to this infection.

Characterization of the Effect of Cell Design on Li−S Battery Resistance Using Electrochemical Impedance Spectroscopy

AbstractThe effect of two critical cathode design parameters, electrolyte‐to‐sulfur (E/S) and carbon‐to‐sulfur (C/S) ratios, on the kinetic and transport resistances in a Li−S cell is determined as a function of discharge depth by using electrochemical impedance spectroscopy. Electrolyte, charge transfer, and Li2S film resistances are identified as the major contributors to cell resistance. Both E/S and C/S ratios have a significant impact on cell resistance, predominantly at the early and final stages of discharge. The E/S ratio controls the cathode kinetics in the first plateau together with Li2S precipitation near the end of discharge. Consequently, the highest cell resistances are obtained for the cell with the lowest E/S ratio of 6 mL g−1. Increasing the E/S ratio up to 19 mL g−1 decreases the resistances considerably, no notable change is achieved after this point. On the other hand, the C/S ratio reflects a tradeoff between high electrochemically active surface area vs. sufficient and homogeneous S loading in the cathode. The minimum cell resistance is attained for the cell with C/S=1; any increase or decrease in the C/S ratio leads to higher resistances. The results suggest a mechanistic interpretation of the connection between cathode design and cell performance in Li−S batteries.

An investigation on electrical and thermal characteristics of cylindrical lithium-ion batteries at low temperatures

Lithium-ion batteries suffer severe performance degradation and exhibit highly nonlinear characteristics under low-temperature environments. Determining the electrical and thermal characteristics is of significant in battery thermal management optimization and electrochemical energy utilization. In this study, the effects of various ambient temperatures and different discharge currents on electro-thermal behaviors are experimentally investigated, and various parameters, as functions of the depth of discharge, are comprehensively analyzed. The results indicate that decreasing the lithium-ion activity and the amount of useable active material and increasing the resistance lead to performance deterioration at low temperatures. The ohmic resistance shows slight deviations in the middle stage of discharge, and the polarization resistance gradually increases and provides the largest contribution to the total resistance as the battery discharge progresses. The irreversible heat generation caused by the internal resistance can be regarded as the sole heat source, to simplify the battery thermal model in certain cases. However, as the temperature increases and discharge current decreases, the reversible heat increases and can no longer be ignored. Finally, a lumped-parameter method is employed to derive the battery temperature. The calculated temperature variation agrees well with the experimental results, thus proving the effectiveness of the measurement.

Flow and heat transfer characteristics in a microchannel with a circular synthetic jet

The combination of a microchannel and a circular synthetic jet has been proven as a promising cooling technology for microelectronic devices. However, the flow control and heat transfer characteristics of a circular synthetic jet in a microchannel are still not clear. This work numerically investigates the interaction between a circular synthetic jet and a cross flow in a microchannel using an in-house solver based on the finite volume method and analyzes its impact on the heat transfer process to further understand the heat transfer enhancement induced by a circular synthetic jet in a microchannel. The effects of the synthetic jet Reynolds number (Resj = 0 to 324), dimensionless stroke length (L/H = 1.8432 to 92.16), and cross-flow Reynolds number (Rec = 188 to 470) are studied herein. The results show that the main body of the vortex structure generated by the circular impinging synthetic jet during the discharge stage is a hairpin vortex. During the downstream motion of the hairpin vortex, the vortex legs gradually stretch and evolve into a pair of large-scale longitudinal vortex. The heat transfer enhancement induced by a circular synthetic jet can be divided into two parts according to the difference in acting mechanism: an impinging region with severe heat transfer fluctuation and an entraining region with a relatively stable heat transfer performance. The parametric study demonstrates that the enhancements of the time-area-averaged Nusselt number and the total pressure drop are mainly affected by Resj, while the transient heat transfer performance is determined by L/H. Furthermore, the growth rates of the time-area-averaged Nusselt number and the total pressure drop are almost independent of Rec.

Implications of Electron Detachment in Associative Collisions of Atomic Oxygen Anion with Molecular Nitrogen for Modeling of Transient Luminous Events

AbstractElectron detachment from O− is important for understanding of lightning‐induced upper atmospheric discharges. Contrary to previous studies, Rayment and Moruzzi (1978) (RM78) argue that the associative detachment reaction of O− with N2 proceeds with N2 in its ground state. Here, we analyze the experimental setup in RM78 and demonstrate that vibrationally excited N2 may have in fact contaminated the results, the theoretical approach in RM78 requires corrections, and the rate calculations provided in RM78 are inconsistent. As the vibrational temperature of N2 remains relatively low in the initial stages of gas discharges in air, i.e., streamer formation, we conclude that if in fact vibrationally excited N2 is required for the O− + N2 → N2O + e reaction to proceed, the process will happen only in later stages of the discharge, e.g., during streamer to leader transition. Controlled experiments are required to reconcile the literature on the reaction of O− with ground state N2.

Diagnosis associated with COVID-19 (U07.1), Pneumonia- Unspecified (J18.9) and other types of admissions: A restricted medical scheme case study- South Africa

The primary objective of this study was to assess the characteristics of patients admitted for COVID-19, ‘J18.9 Pneumonia, unspecified organism’ and other types of diagnoses. The aim was to assess as to what extent do COVID-19 related admissions changed to pneumonia, and as to what extent do ‘J18.9 Pneumonia, unspecified organism’ related admissions that changed to COVID-19 diagnosis at discharge stage. The secondary objective of the study was to assess’ predictors of readmissions in private hospitals. The review period was private hospital claims received by the scheme between January and August 2020. The inclusion criteria for COVID-19 admissions were patients that had a laboratory-confirmed (RT – PCR assay) COVID-19. Predictors of readmissions were modelled using logistic regression. The study found that restricted scheme patients admitted for a COVID-19 diagnosis changed to a ‘J18.9 Pneumonia, unspecified organism’ diagnosis. The converse was found to be true in that some patients that were admitted as J18.9 Pneumonia, unspecified organism’ diagnosis changed to a COVID-19 diagnosis. This study showed underlying factors associated with hospital admissions and predictors of readmissions in private hospitals. Keywords: COVID-19, Diagnosis, Hospitalisation, ICD-10, Pneumonia, Risk factors

Pattern Recognition of Development Stage of Creepage Discharge of Oil–Paper Insulation under AC–DC Combined Voltage Based on OS-ELM

The recognition of the creepage discharge development process of oil–paper insulation under AC–DC combined voltage is the basis for fault monitoring and diagnosis of converter transformers; however, only a few related studies are available. In this study, the AC–DC combined voltage with a ratio of 1:1 was used to develop a recognition method for the creepage discharge development process of an oil–paper insulation under a cylinder–plate electrode structure. First, the pulse current method was used to collect the discharge signals in the creepage discharge development process. Then, 24 characteristic parameters were extracted from four types of creepage discharge characteristic spectra after dimensionality reduction. Finally, based on the online sequential extreme learning machine (OS-ELM) algorithm, these characteristic parameters were used to recognize the development stage of the creepage discharge of the oil–paper insulation. The results showed that when the size of the sample training set used in the OS-ELM algorithm is close to the number of hidden layer neurons, a high recognition accuracy can be obtained, and the type of activation function has little influence on the recognition accuracy. Four stages of the creepage discharge development process were recognized using the OS-ELM algorithm; the trend was the same as that of the characteristic parameters of the entire creepage discharge development process. The recognition accuracy was 91.4%. The algorithm has a high computing speed and high accuracy and can train data in batches. Therefore, it can be widely used in the field of online monitoring and evaluation of electrical equipment status.

Energy cost and efficiency analysis of greenhouse heating system enhancement using phase change material: An experimental study

The growing production of greenhouse gases and fossil fuels price obligated decision-makers in communications to implement energy sources more efficiently. The greenhouses have been developed through the years for the safe production of food sources. Thermal energy devotes a large portion of energy need in greenhouses. In developing countries, the rate of fuel consumption in the greenhouse is high, and there is an urgent need for improving heating systems. Here the possibility of reusing and storing the waste heat by phase change material (PCM) in a sample greenhouse studied experimentally. The PCM heat recovery system (PCM HRS) is a20cm×50cm×140cm plate type heat exchanger where the plates are replaced with PCM plate containers. The charge and discharge of the system are performed in two separate sections. The discharge stage organized in two separate schemes: delivering the stored heat directly inside the greenhouse space and using stored heat to preheat the combustion air of the burner. The heating system analyzed from the viewpoint of energy and the results show that the effect of preheating the heater air gives rise to a 23.7% reduction of gas consumption and the effect is much more pronounced compared to the direct using of the stored heat. Also, the resulted energy saving obtained by using the PCM HRS returns the initial investment within four months.

Initiation of nanosecond-pulsed discharge in water: Electrostriction effect

Underwater nanosecond-pulsed discharges have been widely utilized in numerous industrial applications. The initial stage of nanosecond-pulsed discharge in water contains extremely abundant physical processes, however, it is still difficult to reveal the details of charge transportation and multiplicative process in liquid within several nanoseconds by currently existing experimental diagnostic techniques. Up to now, the initiation mechanism of underwater nanosecond discharge has been still a puzzle. In this paper, we develop a two-dimensional axially symmetric underwater discharge model of pin-to-plane, and numerically investigate the electrostriction process, cavitation process, and ionization process in water, induced by nanosecond-pulsed voltage. The negative pressure in water caused by tensile ponderomotive force is calculated. The creation of nanoscale cavities (so-called nanopores) in liquid due to negative pressure is modeled by classical nucleation theory with modified nucleation energy barrier. When estimating the temporal development of nanopore radius, a varying hydrostatic pressure is considered to restrain the unlimited expansion of nanopores. We estimate the electron generation rate by the product of the generation rate of incident electrons and the number density of nanopores. The simulation results show that cavitation occurs in liquid within several microns from pin electrode due to the electrostriction, which results in the formation of a large number of nanopores. The expansion of nanopore, caused by electrostrictive pressure on nanopore surface, provides a sufficient acceleration distance for electrons. The impact ionization of water molecules can be triggered by energetic electrons, leading the local liquid to be ionized rapidly. The effects of nanopores on rapid electron generation in water are discussed. Once nanopores are formed, the electrons can be generated in the following ways: 1) Field ionization of water molecules on the nanopore wall continuously provides seed electrons; 2) the seed electrons accelerated in nanopores enter into the liquid and collide with water molecules, resulting in the rapid increase of electrons. It can be inferred that the randomly scattered nanopores act as micro-sources of charges that contribute to the continuing ionization of liquid water in cavitation region near pin electrode. Electrostriction mechanism provides a new perspective for understanding the initiation of nanosecond-pulsed discharge in water.

Influence of Aging on Creepage Discharge Characteristics of Oil-Paper Insulation Under AC-DC Combined Voltage

There is a relative lack of research on the development of creepage discharge in aged oil-paper insulation subjected to AC-DC combined voltage in converter transformers. In this study, based on the physical and chemical properties of oil-paper, we propose a sphere-plate electrode model to study the creepage discharge parameters and characteristic spectra of aged oil-paper subjected to AC-DC combined voltage. The results show that the creepage discharge inception voltage of aged oil-paper is related to the AC voltage component of the AC-DC combined voltage. However, when the DC voltage component is 60 kV, the flashover phenomenon was found to occur in one of the severely aged samples before the AC voltage was applied. Despite being subjected to the same DC voltage, the flashover phenomenon did not occur in three other samples aged to different degrees. Large-amplitude discharges were found to appear earlier in the severely aged samples. At the same creepage discharge stage, as the aging time of the oil-paper increased, the number of large-amplitude discharges was found to rapidly increase, and the time interval between adjacent discharges was found to gradually decrease. At each stage of the creepage discharge, the small-amplitude discharge has a “hump” shaped distribution. The larger the DC voltage component, the shorter the endurance time of aged oil-paper, and the more severe the damage to the oil-paper. The DC voltage component was found to have an accelerating effect on the development of creepage discharge in aged oil-paper insulation.

The Research on the Microscopic Mechanism and Dynamical Characteristics of DC Positive Corona Discharge in Pure O₂

We systemetically research the microscopic physical mechanism of positive corona discharge and comprehensively analyse the regular and irregular pulsed oscillations of discharge outputs. Especially, we discover the formation mechanism of irregular pusled discharge phenomenon for the positive corona and give a profound explanation. Accorinding to the physical process of discharge, we propsoe a new dynamical model which can describe the Trichel pulsed discahrge outputs and the characteristics of waveforms. Based on nonlinear dynamics method, we predict and analyse differernt stages of discharge. In particular, the experimentally observed irregularly pusled discharge on positive corona is reproduced by the presented theory. Our study reveals that the positive ions as current carriers predominate in the total current and the photons occurring can be treated as the feedback signal in the nonlinear process of discharge system. We find that the photo-ionization is an indispensable role as the source forming electron avalanches for sustaining the positive corona discharge. Moreover, according to quantum mechanics we demonstrate the high frequency photons with energy higher than the ionization energy may photo-ionize oxygen molecules in pure oxygen. We point out that the recombination radiation is competent to photo-ionize neutral molecules producing the seed electrons. Besides, we analyze the characteristics of diversely pulsed outputs and further explain the microscopic menchnism generating the symmetric and asymmetric sharp jagged pulses. Furthermore, we discover the intrinsic physical relations between positive ion and surface electric field, and the significant influnces of the attributes of different particles on the discharge behaviors.