Pub Date : 2017-02-07DOI: 10.4236/JEMAA.2017.92004
K. Saka
Asymmetric Electrostatic Force is a very interesting phenomenon. The intensity of the electrostatic force that acts on a charged asymmetric shaped conductor changes when the direction of the electric field is reversed. The theory of this phenomenon is not clear until today. Therefore this paper will clearly explain the theory of this phenomenon with Gauss’s law. Total ΣES on a closed Gaussian surface around a disk-cylinder shaped charged conductor is the same before and after when the direction of the electric field is reversed. However the distribution of ΣES changes. Many part of total ΣES gather on the front surface of the disk when the electric field is generated. But they transfer to the peripheral side of the cylinder when the direction of the electric field is reversed. This result means that many charges transferred from the surface to the peripheral side. As a result the intensity of the field direction electrostatic force becomes weak.
{"title":"Theory of Asymmetric Electrostatic Force","authors":"K. Saka","doi":"10.4236/JEMAA.2017.92004","DOIUrl":"https://doi.org/10.4236/JEMAA.2017.92004","url":null,"abstract":"Asymmetric Electrostatic Force is a very interesting phenomenon. The intensity of the electrostatic force that acts on a charged asymmetric shaped conductor changes when the direction of the electric field is reversed. The theory of this phenomenon is not clear until today. Therefore this paper will clearly explain the theory of this phenomenon with Gauss’s law. Total ΣES on a closed Gaussian surface around a disk-cylinder shaped charged conductor is the same before and after when the direction of the electric field is reversed. However the distribution of ΣES changes. Many part of total ΣES gather on the front surface of the disk when the electric field is generated. But they transfer to the peripheral side of the cylinder when the direction of the electric field is reversed. This result means that many charges transferred from the surface to the peripheral side. As a result the intensity of the field direction electrostatic force becomes weak.","PeriodicalId":58231,"journal":{"name":"电磁分析与应用期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41927177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-02-07DOI: 10.4236/JEMAA.2017.92002
O. Dardeer, T. Abouelnaga, A. Mohra, H. El-Hennawy
In this paper, two ultra-wide band power dividers are introduced. Compact equal power divider is considered firstly where an extended transmission lines and double open stubs are used in order to increase the bandwidth. Secondly, an unequal UWB power divider is introduced where multi-stage impedance is used. The proposed power dividers are fabricated and measured. The overall sizes of the proposed power dividers are 11.37 × 17.87 mm2 for the equal one and 12.13 × 29.03 mm2 for the unequal power divider. The simulated results are compared with the measured results and good agreement is obtained.
{"title":"Compact UWB Power Divider, Analysis and Design","authors":"O. Dardeer, T. Abouelnaga, A. Mohra, H. El-Hennawy","doi":"10.4236/JEMAA.2017.92002","DOIUrl":"https://doi.org/10.4236/JEMAA.2017.92002","url":null,"abstract":"In this paper, two ultra-wide band power dividers are introduced. Compact equal power divider is considered firstly where an extended transmission lines and double open stubs are used in order to increase the bandwidth. Secondly, an unequal UWB power divider is introduced where multi-stage impedance is used. The proposed power dividers are fabricated and measured. The overall sizes of the proposed power dividers are 11.37 × 17.87 mm2 for the equal one and 12.13 × 29.03 mm2 for the unequal power divider. The simulated results are compared with the measured results and good agreement is obtained.","PeriodicalId":58231,"journal":{"name":"电磁分析与应用期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42121977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-02-07DOI: 10.4236/JEMAA.2017.92003
D. N. Katole, M. Daigavane, S. P. Gawande, P. Daigavane
This paper mainly concentrates on design of improved controller and its implementation based on single phase synchronous reference frame theory (SRFT) for Dynamic Voltage Restorer (DVR) compensating voltage sag particularly for nonlinear load. In case of single phase distribution line with nonlinear load, the complexity of controller’s design becomes more serious issue. The present single phase and/or three phase theories applicable to DVR shows poor response to restore voltage sag in case of nonlinear load due to presence of harmonics. Hence restoration of voltage sag in single phase nonlinear load connected system has been a serious concern. Therefore, new controller for DVR has been proposed incorporating effective design concept for fundamental component extraction in case of nonlinear load. The single phase SRFT based main controller for DVR works on two separate closed path viz. feed forward path for quick transient response and feedback path for reducing the steady state error. Moreover, pre-sag mitigation strategy of DVR has been adapted through these two aforementioned paths. Complete design of proposed controller is based on phasor analysis. It also consist of proportional integral (PI) controller to reduce the error in the DC-link voltage during compensation time. The controller performance has been verified in MATLAB Simulink for both types (linear and nonlinear) of load. The results obtained indicates that the proposed controller is effective in its performance.
{"title":"Modified Single Phase SRF d-q Theory Based Controller for DVR Mitigating Voltage Sag in Case of Nonlinear Load","authors":"D. N. Katole, M. Daigavane, S. P. Gawande, P. Daigavane","doi":"10.4236/JEMAA.2017.92003","DOIUrl":"https://doi.org/10.4236/JEMAA.2017.92003","url":null,"abstract":"This paper mainly concentrates on design of improved controller and its implementation based on single phase synchronous reference frame theory (SRFT) for Dynamic Voltage Restorer (DVR) compensating voltage sag particularly for nonlinear load. In case of single phase distribution line with nonlinear load, the complexity of controller’s design becomes more serious issue. The present single phase and/or three phase theories applicable to DVR shows poor response to restore voltage sag in case of nonlinear load due to presence of harmonics. Hence restoration of voltage sag in single phase nonlinear load connected system has been a serious concern. Therefore, new controller for DVR has been proposed incorporating effective design concept for fundamental component extraction in case of nonlinear load. The single phase SRFT based main controller for DVR works on two separate closed path viz. feed forward path for quick transient response and feedback path for reducing the steady state error. Moreover, pre-sag mitigation strategy of DVR has been adapted through these two aforementioned paths. Complete design of proposed controller is based on phasor analysis. It also consist of proportional integral (PI) controller to reduce the error in the DC-link voltage during compensation time. The controller performance has been verified in MATLAB Simulink for both types (linear and nonlinear) of load. The results obtained indicates that the proposed controller is effective in its performance.","PeriodicalId":58231,"journal":{"name":"电磁分析与应用期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48199805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-16DOI: 10.4236/JEMAA.2016.812025
A. Chaibo, A. Ngom, M. Y. Khayal, K. Talla, A. Beye
This paper presents the design of a compact bow-tie antenna with triple band notched characteristics for UWB applications. The proposed antenna can operate from 3.1 to 10.6 GHz with VSWR - 8.4 GHz) centered at 8.1 GHz, the CSRR2 rejects the WLAN band (5.15 - 5.85 GHz) centered at 5.6 GHz, and the CSRR3 rejects the band (4.10 - 4.47 GHz) centered at 4.32 GHz. Compared with recent design, this antenna is more compact, and presents better simulation results of its characteristics. Our newly designed antenna is a potential candidate for application in UWB communication systems.
{"title":"A Novel Bow-Tie Antenna with Triple Band-Notched Characteristics for UWB Applications","authors":"A. Chaibo, A. Ngom, M. Y. Khayal, K. Talla, A. Beye","doi":"10.4236/JEMAA.2016.812025","DOIUrl":"https://doi.org/10.4236/JEMAA.2016.812025","url":null,"abstract":"This paper presents the design of a compact bow-tie antenna with triple band notched characteristics for UWB applications. The proposed antenna can operate from 3.1 to 10.6 GHz with VSWR - 8.4 GHz) centered at 8.1 GHz, the CSRR2 rejects the WLAN band (5.15 - 5.85 GHz) centered at 5.6 GHz, and the CSRR3 rejects the band (4.10 - 4.47 GHz) centered at 4.32 GHz. Compared with recent design, this antenna is more compact, and presents better simulation results of its characteristics. Our newly designed antenna is a potential candidate for application in UWB communication systems.","PeriodicalId":58231,"journal":{"name":"电磁分析与应用期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70292339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-16DOI: 10.4236/JEMAA.2016.812024
C. Hung, S. M. Yang
The performance of a microstrip antenna has been known sensitive to substrate’s dielectric properties, which is dependent on the angle of laminate layers inside a composite laminated substrate. Modal analysis in spectral domain is applied to investigate the resonant frequency and radiation pattern of rectangular microstrip antenna on composite substrates. It is shown that the substrate’s dielectric properties are dependent upon the laminate angles, i.e., upon the orientation of the antenna relative to the substrate’s fiber direction. For the same operating frequency, the antenna size on composite substrates is larger than that on isotropic substrates, and the far field pattern is also more directional.
{"title":"The Effect of Laminate Angles in Composite Substrates on the Performance of Rectangular Microstrip Antenna","authors":"C. Hung, S. M. Yang","doi":"10.4236/JEMAA.2016.812024","DOIUrl":"https://doi.org/10.4236/JEMAA.2016.812024","url":null,"abstract":"The performance of a microstrip antenna has been known sensitive to substrate’s dielectric properties, which is dependent on the angle of laminate layers inside a composite laminated substrate. Modal analysis in spectral domain is applied to investigate the resonant frequency and radiation pattern of rectangular microstrip antenna on composite substrates. It is shown that the substrate’s dielectric properties are dependent upon the laminate angles, i.e., upon the orientation of the antenna relative to the substrate’s fiber direction. For the same operating frequency, the antenna size on composite substrates is larger than that on isotropic substrates, and the far field pattern is also more directional.","PeriodicalId":58231,"journal":{"name":"电磁分析与应用期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70292277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-12-01DOI: 10.4236/JEMAA.2017.91001
E. Deyo
This paper gives a method that maps the static magnetic field due to a system of parallel current-carrying wires to a complex function. Using this function simplifies the calculation of the magnetic field energy density and inductance per length in the wires, and we reproduce well-known results for this case.
{"title":"A Method to Calculate Inductance in Systems of Parallel Wires","authors":"E. Deyo","doi":"10.4236/JEMAA.2017.91001","DOIUrl":"https://doi.org/10.4236/JEMAA.2017.91001","url":null,"abstract":"This paper gives a method that maps the static magnetic field due to a system of parallel current-carrying wires to a complex function. Using this function simplifies the calculation of the magnetic field energy density and inductance per length in the wires, and we reproduce well-known results for this case.","PeriodicalId":58231,"journal":{"name":"电磁分析与应用期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70293031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-11-16DOI: 10.4236/JEMAA.2016.811023
J. Kappatou, Georgios D. Zalokostas, Dimitrios A. Spyratos
This paper deals with the investigation of the behavior of a low speed, dual rotor-single coreless stator, axial flux permanent magnet synchronous machine for small power applications. Firstly, with the use of nonlinear 3D FEM electromagnetic analysis, four models with different magnet topologies are designed, simulated and compared. With criteria such as output power, power factor and torque ripple, the best performing model is selected and a further investigation, regarding the effect of the disk rotor material on the behavior of the machine, is conducted. The simulation results show how the different types of commercially available steel types affect the magnetic field and the performance of the machine.
{"title":"Design Optimization of Axial Flux Permanent Magnet (AFPM) Synchronous Machine Using 3D FEM Analysis","authors":"J. Kappatou, Georgios D. Zalokostas, Dimitrios A. Spyratos","doi":"10.4236/JEMAA.2016.811023","DOIUrl":"https://doi.org/10.4236/JEMAA.2016.811023","url":null,"abstract":"This paper deals with the investigation of the behavior of a low speed, dual rotor-single coreless stator, axial flux permanent magnet synchronous machine for small power applications. Firstly, with the use of nonlinear 3D FEM electromagnetic analysis, four models with different magnet topologies are designed, simulated and compared. With criteria such as output power, power factor and torque ripple, the best performing model is selected and a further investigation, regarding the effect of the disk rotor material on the behavior of the machine, is conducted. The simulation results show how the different types of commercially available steel types affect the magnetic field and the performance of the machine.","PeriodicalId":58231,"journal":{"name":"电磁分析与应用期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70292266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-09-30DOI: 10.4236/JEMAA.2016.810020
P. O. Leye, A. Khenchaf, P. Pouliguen
This paper is mainly devoted to application of the Gaussian beam summation technique in electromagnetic simulations problem. Gaussian beams are asymptotic solutions of the Helmholtz equation within the paraxial approximation. Since they are insensitive to ray transition region, several techniques based on Gaussian beam are used to evaluate high frequency EM wave equation, which overcome partially or fully the difficulties of singular regions (caustics, zero field in shadow zones). This paper concentrates on the explicit formulation of the electromagnetic field scattered from radar target. In this approach, when the incident field illuminates the target, the scattering is accounted in a complex weighing function. The wave field at a receiver is evaluated as superposition of Gaussian beams concentrated close to rays emerging from the target, passing through the neighbor of the receiver.
{"title":"The Gaussian Beam Summation and the Gaussian Launching Methods in Scattering Problem","authors":"P. O. Leye, A. Khenchaf, P. Pouliguen","doi":"10.4236/JEMAA.2016.810020","DOIUrl":"https://doi.org/10.4236/JEMAA.2016.810020","url":null,"abstract":"This paper is mainly devoted to application of the Gaussian beam summation technique in electromagnetic simulations problem. Gaussian beams are asymptotic solutions of the Helmholtz equation within the paraxial approximation. Since they are insensitive to ray transition region, several techniques based on Gaussian beam are used to evaluate high frequency EM wave equation, which overcome partially or fully the difficulties of singular regions (caustics, zero field in shadow zones). This paper concentrates on the explicit formulation of the electromagnetic field scattered from radar target. In this approach, when the incident field illuminates the target, the scattering is accounted in a complex weighing function. The wave field at a receiver is evaluated as superposition of Gaussian beams concentrated close to rays emerging from the target, passing through the neighbor of the receiver.","PeriodicalId":58231,"journal":{"name":"电磁分析与应用期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70292134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-09-30DOI: 10.4236/JEMAA.2016.810022
Hao-Tao Hu, Zhigang Lu
A novel compact multiple-input-multiple-output (MIMO) antenna for portable ul-trawideband (UWB) applications is presented. This antenna consists of two modified planar-monopole antenna elements with coplanar waveguides-fed printed on one side of the substrate. To enhance isolation and increase impedance bandwidth, a tree like stubs is placed on the ground plane at the 45° axis. The measured results show that the MIMO antenna operates from 2.3 GHz to 13 GHz, covering WLAN, WiMAX, and UWB. The low mutual coupling and low envelope correlation coefficient of less than 0.2 across the whole frequency band proved that this antenna was suitable for MIMO/diversity systems. Also, good performance of radiation patterns and the antenna’s compact size make it a good candidate for portable devices.
{"title":"A Compact UWB MIMO Antenna for Portable Applications","authors":"Hao-Tao Hu, Zhigang Lu","doi":"10.4236/JEMAA.2016.810022","DOIUrl":"https://doi.org/10.4236/JEMAA.2016.810022","url":null,"abstract":"A novel compact multiple-input-multiple-output (MIMO) antenna for portable ul-trawideband (UWB) applications is presented. This antenna consists of two modified planar-monopole antenna elements with coplanar waveguides-fed printed on one side of the substrate. To enhance isolation and increase impedance bandwidth, a tree like stubs is placed on the ground plane at the 45° axis. The measured results show that the MIMO antenna operates from 2.3 GHz to 13 GHz, covering WLAN, WiMAX, and UWB. The low mutual coupling and low envelope correlation coefficient of less than 0.2 across the whole frequency band proved that this antenna was suitable for MIMO/diversity systems. Also, good performance of radiation patterns and the antenna’s compact size make it a good candidate for portable devices.","PeriodicalId":58231,"journal":{"name":"电磁分析与应用期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70292208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-09-30DOI: 10.4236/JEMAA.2016.810021
V. Grimalsky, S. Koshevaya, J. Escobedo-Alatorre, M. Tecpoyotl-Torres
The nonlinear waves of terahertz (THz) range are investigated in the paraelectric crystals SrTiO3 at the temperatures ~77 K. The frequency dispersion is important there. In the absence of a bias electric field the dominating nonlinearity is cubic. The frequency dispersion and nonlinearity correspond to existence of envelope solitons and the modulation instability (MI) of long input pulses, whereas in the transverse direction MI is absent. There exists a possibility to generate the regular sequences of short THz pulses due to MI in bounded SrTiO3 crystals. The focusing of input long pulses reduces the threshold of MI, increases the output amplitudes of the short pulses, and provides more stable generation of the short pulses. It is investigated the frequency multiplication of THz electromagnetic radiation in bounded paraelectric SrTiO3 when a bias electric field is applied. The dominating nonlinearity is quadratic there. The frequency dispersion and the transverse width of the input wave beams affect the generation of higher harmonics. It is possible to select the certain numbers of higher harmonics by means of the optimum length of the crystal, by the width of the beam of the input first harmonic, and by the focusing of the input first harmonic.
{"title":"Nonlinear Terahertz Electromagnetic Waves in SrTiO3 Crystals under Focusing","authors":"V. Grimalsky, S. Koshevaya, J. Escobedo-Alatorre, M. Tecpoyotl-Torres","doi":"10.4236/JEMAA.2016.810021","DOIUrl":"https://doi.org/10.4236/JEMAA.2016.810021","url":null,"abstract":"The nonlinear waves of terahertz (THz) range are investigated in the paraelectric crystals SrTiO3 at the temperatures ~77 K. The frequency dispersion is important there. In the absence of a bias electric field the dominating nonlinearity is cubic. The frequency dispersion and nonlinearity correspond to existence of envelope solitons and the modulation instability (MI) of long input pulses, whereas in the transverse direction MI is absent. There exists a possibility to generate the regular sequences of short THz pulses due to MI in bounded SrTiO3 crystals. The focusing of input long pulses reduces the threshold of MI, increases the output amplitudes of the short pulses, and provides more stable generation of the short pulses. It is investigated the frequency multiplication of THz electromagnetic radiation in bounded paraelectric SrTiO3 when a bias electric field is applied. The dominating nonlinearity is quadratic there. The frequency dispersion and the transverse width of the input wave beams affect the generation of higher harmonics. It is possible to select the certain numbers of higher harmonics by means of the optimum length of the crystal, by the width of the beam of the input first harmonic, and by the focusing of the input first harmonic.","PeriodicalId":58231,"journal":{"name":"电磁分析与应用期刊(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70292148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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