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Optimization of reluctance accelerator efficiency by an improved discharging circuit

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Defence Technology（防务技术） 2020年第3期16卷 662-667页

作者： Hui-min Deng Yu Wang fa-long Lu Zhong-ming Yan School of Electrical Engineering Southwest Jiaotong UniversityChengdu610031China

In this paper,an improved discharging circuit was proposed to quicken the decay of the current in the drive coil in a reluctance accelerator when the armature reaches the center of the *** aim of this is to prevent the suck-back effect caused by the residual current in drive *** method is adding a reverse charging branch with a small capacitor in the traditional pulsed discharging *** results under the traditional circuit and the improved circuit were compared in a *** experiment then verified the simulations and they had good *** and experiment both demonstrated the improved circuit can effectively prevent the suck-back effect and increase the *** the voltage of 800 V,an efficiency increase of 36.34% was obtained.

关键词： Reluctance accelerator Suck-back effect Discharging circuit Current decay Efficiency optimization

Review on monitoring and prevention technologies of splashing induced by inappropriate slag foaming in BOF

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journal of Iron and Steel Research International 2023年第9期30卷 1661-1674页

作者： Rui-fang Wang Bo Zhang Cheng-jun Liu Mao-fa jiang Key Laboratory for Ecological Metallurgy of Multimetallic Ores(Ministry of Education) Northeastern UniversityShenyang 110819LiaoningChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization Baotou Research Institute of Rare EarthsBaotou 014030Inner MongoliaChina

Basic oxygen steelmaking(BOS)is the most frequently used method to produce molten steel,which is being developed to meet the requirements of being safe,efficient,clean,and *** the BOS process,splashing events cause undesirable consequences,such as casualties,low efficiency,environmental pollution,and uncontrollable *** causes of three types of splashing(eruptive,foaming,and metallic splashing)were unraveled and it is concluded that inappropriate foaming is the root cause of splashing.A variety of monitoring techniques for splashing have been developed to measure real-time slag foaming in a basic oxygen furnace(BOF).The audiometry technique with flexible operation and high accuracy was comprehensively introduced with a practical *** on the formation mechanisms,the countermeasures for the three types of splashing were proposed to regulate slag foaming in a BOF by integrating diverse measures in terms of raw materials,slag forming,blowing pattern,and the use of splashing regulating *** work should emphasise an automatic action for these prevention measures in response to the splashing risk from the monitoring technology,promoting the progress of intelligent steelmaking.

关键词： Steelmaking Splashing Slag foaming Monitoring Prevention

Effect of Magnesium on Evolution of Oxide and Sulphide in Liquid Iron at 1873K

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journal of Iron and Steel Research International 2014年第12期21卷 1073-1080页

作者： Tong-sheng ZHANG De-yong WANG Mao-fa jIANG Institute of Ferrous Metallurgy Northeastern University

To reveal the effects of magnesium on the evolution of oxide and sulphide inclusions in liquid iron, both thermodynamic calculations and deoxidization experiments were carried out. The samples extracted from the liquid iron were polished and analyzed by optical microscopy and scanning electron microscopy. The results showed that magne sium could modify oxide and sulphide inclusions simultaneously. Spherical MgO and irregular spinel inclusions were observed in the samples. The elongated MnS inclusions were replaced by small MgO · MgS or MgO · MgS · MnS complex inclusions, and the sulphides were distributed dispersively. The evolution mechanisms of inclusions were discussed comprehensively, and a proposed model for the formation of oxysulphide was set up.

关键词： magnesium inclusion oxysulphide thermodynamics liquid iron

Context-dependency in medicine:how neuronal excitability influences the impact of dopamine on cognition

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Neural Regeneration Research 2025年第11期20卷 3225-3226页

作者： Mahboubeh Ahmadi Nahid Rouhi javad Mirnajafi-Zadeh Bechara j.Saab Department of Physiology Faculty of Medical SciencesTarbiat Modares UniversityTehranIran Mobio Interactive Pte.Ltd. SingaporeRepublic of Singapore

Dopamine,often termed the"feel-good"neurotransmitter,plays a crucial role in myriad physiological and psychological brain *** dopamine is primarily associated with pleasure,reward,and motivation,its effects can be quite complex;and this complexity is further compounded when examining how dopamine functions in typical versus disease-affected neural *** pa rticula r,epilepsy,characte rized by heightened brain excitability,is linked to cognitive dysfunction,and dopamine is implicated in elements of both its pathology and *** has been successful in describing the synaptic abnormalities believed to contribute to memory issues in epilepsy,aiding in the search for effective therapies for what persists as a major medical issue.

关键词： dopamine epilepsy primarily

Preparation and Dielectric Properties of Nonstoichiometric β-SiC Powder by Combustion Synthesis

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journal of Materials Science & Technology 2009年第3期25卷 401-404页

作者： Xiaolei Su Wancheng Zhou Zhimin Li fa Luo Dongmei Zhu State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi＇an 710072 China College of Mechanical ＆ Electronic Engineering Xi＇an Polytechnic University Xi＇an 710048 China School of Technical Physics Xidian University Xi＇an 710071 China

The nonstoichiometric β-SIC powders were synthesized via combustion reaction of Si and C system in a 0.1 MPa nitrogen atmosphere, using Teflon as the chemical activator. The prepared powders were invistigated by XRD and Raman spectra. The results indicates that the cell parameters of all the prepared β-SIC powder are smaller than the standard value of β-SIC because of generation of CSi defects. The complex permittivity of prepared products was carried out in the frequency range of 8.2-12.4 GHz. It shows that the dielectric property of prepared β-SiC powder decrease with increasing PTFE content. The effect of CSi defects on dielectric property of β-SiC powder has been discussed.

关键词： Silicon carbide Carbon antisite Dielectric property

Effects and Mechanisms of RE on Impact Toughness and Fracture Toughness of Clean Heavy Rail Steel

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journal of Iron and Steel Research International 2011年第3期18卷 52-58页

作者： LIU Cheng-jun HUANG Ya-he jIANG Mao-fa School of Materials and Metallurgy Northeastern UniversityShenyang 110004LiaoningChina

Clean high carbon heavy rail steel was prepared by the process of vacuum induction furnace smelting,forging and *** of RE on the impact toughness and fracture toughness for clean high carbon steel were *** addition,the appropriate range of RE content for clean high carbon steel was *** the austenite grain size and pearlite lamellar spacing decreased due to small amount of RE,consequently the impact toughness and fracture toughness were improved *** the RE content exceeded a critical value,the pearlite lamellar spacing was increased,because RE was segregated on the austenite grain boundaries,damaged the orientation relationship of pearlite transformation,caused the disorder growth and morphology degenerating of *** the increasing of RE content,both the impact toughness and fracture toughness of clean high carbon steel were gradually increased at first and then *** was found that when the RE content was between 0.0081% and 0.0088%,both the impact toughness and fracture toughness of clean high carbon heavy rail steel were the *** maximum ballistic work was 21.2 j（20 ℃） and 12.2 j（-20 ℃）,*** maximum plane-strain fracture toughness was 45.67 MPa·m1/2（20 ℃） and 37.04 MPa·m1/2（-20 ℃）,respectively.

关键词： rare earth high carbon steel heavy rail steel clean steel impact toughness fracture toughness

Anisotropic diffusion of volatile pollutants at air-water interface

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Water Science and Engineering 2013年第2期6卷 153-163页

作者： Li-ping CHEN jing-tao CHENG Guang-fa DENG College of Urban Construction and Safety Engineering Nanjing University of Technology jiangsu Frontier Electric Technology Co. Ltd.

The volatile pollutants that spill into natural waters cause water pollution. Air pollution arises from the water pollution because of volatilization. Mass exchange caused by turbulent fluctuation is stronger in the direction normal to the air-water interface than in other directions due to the large density difference between water and air. In order to explore the characteristics of anisotropic diffusion of the volatile pollutants at the air-water interface, the relationship between velocity gradient and mass transfer rate was established to calculate the turbulent mass diffusivity. A second-order accurate smooth transition differencing scheme （STDS） was proposed to guarantee the boundedness for the flow and mass transfer at the air-water interface. Simulations and experiments were performed to study the trichloroethylene （C2HC13） release. By comparing the anisotropic coupling diffusion model, isotropic coupling diffusion model, and non-coupling diffusion model, the features of the transport of volatile pollutants at the air-water interface were determined. The results show that the anisotropic coupling diffusion model is more accurate than the isotropic coupling diffusion model and non-coupling diffusion model. Mass transfer significantly increases with the increase of the air-water relative velocity at a low relative velocity. However, at a higher relative velocity, an increase in the relative velocity has no effect on mass transfer.

关键词： volatile pollutant," interfacial mass transfer anisotropic diffusion STDS anisotropic coupling diffusion model

Growth behavior of spinel in stainless steel slag during cooling process

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journal of Iron and Steel Research International 2018年第11期25卷 1131-1139页

作者： Long-hu Cao Cheng-jun Liu Qing Zhao Mao-fa jiang Key Laboratory for Ecological Metallurgy of Multimetallic Ores (Ministry of Education) Northeastern University Shenyang 110819LiaoningChina School of Metallurgy Northeastern University Shenyang 110819LiaoningChina

Spinel is an appropriate phase for sequestrating chromium in stainless steel slag to prevent chromium from polluting,and the crystal size of spinel has a significant effect on the stability of chromium and the extraction efficiency of *** enrichment behavior of chromium in spinel during cooling process was investigated,and the growth process of spinel was studied based on the crystal size distribution *** results showed that the enrichment degree of chromium in spinel increased from 88.5% to nearly 100% during the cooling process from 1773 to 1573 K at a rate of 5 K/*** mean diameter of spinel in stainless steel slag had an obvious growth in the cooling process,and a rapid growth of spinel occurred during the cooling process from 1623 to 1523 *** results indicated that the leaching amount of chro- mium could reduce to less than 0.01 mg/L by controlling the cooling *** growth mechanism of spinel was investigated and proposed to consist of two stages:in the first stage,the spinel was in the surface-controlled growth with a decaying nucleation rate from 1773 to 1573 K,and in the second stage,the growth mechanism was transformed to supply- controlled Ostwald ripening-below 1573 K.

关键词： Stainless steel slag Spinel Chromium Growth mechanism Crystal size distribution

Numerical Simulation for Effect of Inlet Cooling Rate on Fluid Flow and Temperature Distribution in Tundish

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journal of Iron and Steel Research International 2012年第7期19卷 12-19页

作者： QU Tian-peng LIU Cheng-jun jIANG Mao-fa CISDI Chongqing Iron and Steelmaking Plant Integration Co Ltd Chongqing 401122China School of Materials and Metallurgy Northeastern UniversityShenyang 110004LiaoningChina

The fluid flow in tundish is a non-isothermal process and the temperature variation of stream from teeming ladle dominates the fluid flow and thermal distribution in tundish. A numerical model was established to investigate the effect of inlet cooling rate on fluid flow and temperature distribution in tundish based on a FTSC （Flexible Thin Slab Casting） tundish. The inlet cooling rate varies from 0. 5 to 0. 25 ~C/rain. Under the present calculation conditions, the following conclusions were made. When the stream temperature from teeming ladle drops seriously （for inlet cooling rate of 0.5℃/min）, there is a ＂backward flow＂ at the coming end of casting. The horizontal flow along the free surface turns to flow along the bottom of tundish. The bottom flow shortens the fluid flow route in tundish and deteriorates the removal effect of nonmetallic inclusions from molten steel. Nevertheless, when the inlet cooling rate decreases to 0.25℃/min, the horizontal flow is sustained during the whole casting period. The present research provides theoretical directions for temperature control in teeming ladle and continuous casting tundish during production of advanced steels.

关键词： tundish thermal distribution unsteady numerical simulation