Jin Lin, Fucheng Zhang, Yongzhen Bai, Xiaobiao Shang, Ruogu Kang
{"title":"Dielectric properties and electromagnetic wave absorbing performance of granular polysilicon during 2450 MHz microwave smelting","authors":"Jin Lin, Fucheng Zhang, Yongzhen Bai, Xiaobiao Shang, Ruogu Kang","doi":"10.1080/08327823.2021.1877242","DOIUrl":"https://doi.org/10.1080/08327823.2021.1877242","url":null,"abstract":"Abstract The dielectric properties and electromagnetic wave absorbing performance of granular polysilicon have important influences on microwave smelting efficiency. In this study, the dielectric parameters (dielectric constant, dielectric loss factor and loss tangent) of granular polysilicon were measured from room temperature (25 °C) to 800 °C at 2450 MHz by using the cylindrical cavity perturbation method, and the reflection loss of granular polysilicon was calculated according to the theory of electromagnetic wave transmission line, and then the effects of temperature on microwave absorbing performance was analyzed. The results indicated that the dielectric constant and dielectric factor loss of granular polysilicon change little before 300 °C, but when the temperature is higher than 300 °C, the dielectric constant and dielectric loss factor increase gradually. The microwave absorbing performance of granular polysilicon fluctuates with the increase of granules thickness, there are multiple absorption peaks, and the position and intensity of absorption peaks change with the increasing temperature. This study provides theoretical guidance for the optimization of smelting process parameters of granular polysilicon and the design of microwave smelting equipment.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"1 1","pages":"66 - 79"},"PeriodicalIF":1.5,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73825267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Study on microwave-assisted grinding and liberation characteristics for Ludwigite","authors":"Wei-jun Huang, Yajing Liu","doi":"10.1080/08327823.2021.1877245","DOIUrl":"https://doi.org/10.1080/08327823.2021.1877245","url":null,"abstract":"Abstract To effectively separate the valuable minerals in ludwigite, this study investigated the grinding fineness behaviour and liberation characteristics. The results indicated that the particle yield of −75 μm with a microwave power of 4 kW for 40 s was increased by 18.22% in comparison to that of raw ore. The D(50) and D(90) raw-ore grinding products reached 53.52 and 215.16 μm, both of which were larger than microwave-treated samples. The particle-size distribution of the grinding products for treated ore was more uniform, and the amount of coarse and over-ground particles decreased significantly. The specific surface area, pore volume and pore diameter of the large particles were effectively increased after microwave heating, which improved the crushing and grinding characteristics of the grinding products by lowering the relevant mechanical properties. The monomer liberations of magnetite, ascharite and serpentine of microwave-treated ore samples were 55.33%, 35.48% and 74.98%, respectively, which represented an increase of 12.06%, 9.37% and 6.22% in comparison to untreated ore samples. The bonding characteristics among different minerals were altered through microwave treatment to weaken the bonding force and reduce the proportion of interlocked minerals, which allows these complex minerals to easily liberate after secondary grinding.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"82 1","pages":"28 - 44"},"PeriodicalIF":1.5,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89342840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Modeling the very broad band dielectric properties of water","authors":"G. Brodie","doi":"10.1080/08327823.2021.1877243","DOIUrl":"https://doi.org/10.1080/08327823.2021.1877243","url":null,"abstract":"Abstract Developing a mathematical model for the dielectric properties of water over a wide range of frequencies helps design, develop, model and optimize processes involving the interaction of electromagnetic waves with water containing materials. Based on large data sets (1744 published dielectric measurements) from literature and significant extensions to mathematical models, which have also been presented in literature, a comprehensive mathematical model for the most important dipolar responses and molecular resonances of water, from radio wave to the ultraviolet frequencies has been developed. This model provides a good approximation to published dielectric properties of pure water. Where possible, it also accounts for the influence of salinity and temperature.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"2 1","pages":"80 - 89"},"PeriodicalIF":1.5,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73198306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Lai, Jingxin Qiao, Nouman Rasool, Kang Li, Huacheng Zhu, Yang Yang
{"title":"A dynamic impedance matching algorithm of three-stub tuners based on equivalent circuit analysis","authors":"S. Lai, Jingxin Qiao, Nouman Rasool, Kang Li, Huacheng Zhu, Yang Yang","doi":"10.1080/08327823.2020.1838051","DOIUrl":"https://doi.org/10.1080/08327823.2020.1838051","url":null,"abstract":"Abstract Three-stub waveguides are common impedance matching devices which are essential for a wide range of high-power microwave applications. Based on equivalent circuit analysis method, this article presents a novel matching algorithm which can be applied for three-stub tuners to implement continuous, automatic and real-time impedance matching. Equivalent model of a stub waveguide is firstly established by using transmission lines in series and capacitors in parallel. Then, according to the proposed model, the mathematical expression of reflection coefficient at different stub depth is derived by using currently detected reflection coefficient and stub depth. Later, based on the derived expression, an algorithm is developed to determine the optimum insertion depths of the stubs when VSWR is minimum. The S 11 parameters of the stub waveguide which are calculated by the method agree well with those measured by vector network analyser. Meanwhile, the algorithm is able to limit reflection coefficient under –10 dB and can easily be redesigned for waveguides of different sizes. Thus, it shows a promising future in industrial impedance matching applications.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"1 1","pages":"330 - 347"},"PeriodicalIF":1.5,"publicationDate":"2020-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89919643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhengkai Yi, Weiqiang Qiu, Yang Jiao, K. Row, Yudong Cheng, Yinzhe Jin
{"title":"Calculation of electric field and temperature distribution within a microwave oven with realistic geometric features geometric features using numeric simulations","authors":"Zhengkai Yi, Weiqiang Qiu, Yang Jiao, K. Row, Yudong Cheng, Yinzhe Jin","doi":"10.1080/08327823.2020.1838048","DOIUrl":"https://doi.org/10.1080/08327823.2020.1838048","url":null,"abstract":"Abstract Many simulations employed in microwave heating simplify the geometric model of the microwave cavity to reduce the complexity of the model. Some detailed design features of the cavity, such as magnetron and cavity depression, are usually ignored. This study built detailed geometric models (DGM) and simplified geometric models (SGM) to investigate the changes in the electric field in a microwave cavity. A three-dimensional finite element model was developed to simulate rotating and stationary food (mashed potatoes) during microwave heating, and the simulation parameters and strategy during rotation were optimized. The simulations using DGM and SGM were compared by comparing the simulated transient temperature profiles and spatial temperature patterns with physical experiments. The results indicate that the temperature patterns of the DGM differed significantly from the SGM, and the simulation results of the DGM were closer to the experimental results. The presence of the magnetron, plastic bearing and detailed glass turntable had little influence on the electric field, but the dents had the great influence. The influence of dents on the heating uniformity was discussed in detail.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"184 ","pages":"3 - 27"},"PeriodicalIF":1.5,"publicationDate":"2020-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72552658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Hernández-Gómez, J. Olvera-Cervantes, A. Corona‐Chavez, B. Corona-Vasquez, T. Kataria, M. Sosa‐Morales
{"title":"Detection of an emerging contaminant in water by dielectric properties in microwave range","authors":"E. Hernández-Gómez, J. Olvera-Cervantes, A. Corona‐Chavez, B. Corona-Vasquez, T. Kataria, M. Sosa‐Morales","doi":"10.1080/08327823.2020.1838047","DOIUrl":"https://doi.org/10.1080/08327823.2020.1838047","url":null,"abstract":"Abstract The complex relative permittivity study of samples of liberdux® syrup dissolved in distilled–deionized water is presented. It should be mentioned that excess of this syrup as pharmaceutical residual in water is considered an emerging contaminant. The study covers liberdux® concentrations from 0% v/v to 100% v/v, which were measured from 500 MHz to 20 GHz. For each sample, the parameters of the Havriliak–Negami model are presented in the range of measurement. Also, the uncertainty study was carried out to determine the sensitivity of the open coaxial probe and it was established that, for concentrations between 8% v/v and 100% v/v, it is possible to determine the concentration of liberdux® in water by the dielectric constant and the loss factor. In addition, a linear relationship was found between the concentration of liberdux® and the α parameter of the Havriliak–Negami model. The study of liberdux® concentrations was also performed with a spectrophotometer and the Beer–Lambert equation. It was established that the spectrophotometer and the open coaxial probe can be used as complements to measure concentrations, the spectrophotometer being the instrument for measuring low concentrations by absorbance, and the open coaxial probe for high concentrations by microwave permittivity.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"1 1","pages":"273 - 290"},"PeriodicalIF":1.5,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79726849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of input microwave power and insulation on microstructure and tensile properties of cast Al 7039 alloy produced at 2.45 GHz","authors":"R. Mishra, A. Sharma","doi":"10.1080/08327823.2020.1838049","DOIUrl":"https://doi.org/10.1080/08327823.2020.1838049","url":null,"abstract":"Abstract In the present work, microwave energy was used for casting Al 7039 alloy at 2.45 GHz in the ambient cavity environment. Effects of input power and insulation of the mould assembly during irradiation on charge melting and mould preheating were studied. Five different casts were produced at 1000 W, 1200 W, 1400 W, 1400 W with an insulated pouring basin and 1400 W with insulated mould assembly. Melting time of the charge was the least while using 1400 W with insulated mould assembly, whereas preheating of the mould was observed minimum during casting at 1400 W inside an insulated pouring basin. Cast microstructures revealed that less preheating of the mould resulted in finer grains and intermetallics, which improve tensile properties of the cast. Fractographic analyses showed the presence of coarse intermetallics in the casts produced with insulated mould assembly, which resulted in significant reduction of tensile properties.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"79 1","pages":"312 - 329"},"PeriodicalIF":1.5,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84082188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Editor’s message: the challenge of virus sanitizing with microwaves","authors":"J. Aguilar-Garib","doi":"10.1080/08327823.2020.1843986","DOIUrl":"https://doi.org/10.1080/08327823.2020.1843986","url":null,"abstract":"Both microorganisms and viruses are germs; the difference is that the first ones are alive while the viruses are a sort of capsules with genetic material that reproduce themselves by replication in...","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"33 1","pages":"271 - 272"},"PeriodicalIF":1.5,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89458963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dielectric properties, polarizability and molar refractive index of some VSrFeZnO glasses","authors":"E. Ahmed, Bushra Al-Hasni","doi":"10.1080/08327823.2020.1838050","DOIUrl":"https://doi.org/10.1080/08327823.2020.1838050","url":null,"abstract":"Abstract Dielectric properties of a set of glasses having the composition (70-x)%V2O5 - x%ZnO − 10%SrO − 20%FeO is studied in terms of their permittivity and electric modulus. The dielectric data are collected at the frequencies 120, 103, 104 and 105 Hz and in the temperature range 300 − 523 K. The electric moduli are treated with different theoretical models. Good fitting to the experimental data are obtained with Cole–Cole and Davidson–Cole equations. The static relaxation time τ0 values are found to vary between 7.6x10−9 sec and 22.7x10−9 sec, and the parameters α and γ are found to be (α = 0.056 − 0.065) and (γ = 0.94 − 0.95). The calculated optical basicity values are found to decrease with increasing the %ZnO. The molar refractive index is found to be between 2.6 and 3.2. The calculated single bond strength values suggest the transfer of bond nature from the covalent to the ionic form. The obtained third-order nonlinear optical susceptibility χ(3) results and electronic polarizability calculations suggests these glasses to be good nominees for nonlinear optical applications.","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"81 1","pages":"291 - 311"},"PeriodicalIF":1.5,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82855260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Editor’s message: a glance to virtual conferences","authors":"Juan Antonio Aguilar Garib","doi":"10.1080/08327823.2020.1800336","DOIUrl":"https://doi.org/10.1080/08327823.2020.1800336","url":null,"abstract":"Coronavirus is a family of viruses, which are the cause of respiratory illnesses, and circulate among humans and animals. One of them, SARS-COV2, produces an illness known as COVID-19, which is ext...","PeriodicalId":16556,"journal":{"name":"Journal of Microwave Power and Electromagnetic Energy","volume":"1 1","pages":"183-185"},"PeriodicalIF":1.5,"publicationDate":"2020-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84725643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}