Papers by Keyword: Electric Field Strength

Abstract: Recently, the composited nanofiber attraction has been growing from researchers across the world due to its exciting opportunities for use in biomedical applications. In this study, we fabricated electrospun fibers from poly (vinyl alcohol) (PVA) composited with Zinc Oxide (ZnO) nanoparticle for potential use in biomedical applications. From the experimental results, there was not any chemical bonding between the ZnO nanoparticles and the PVA molecules. The effect of concentration of ZnO nanoparticles in PVA solution on the diameter of electrospun fibers was found that the diameter of electrospun fibers increased with raising the concentration of suspended ZnO nanoparticles in solution. This is probably because the effect of nanoparticles on the diameter of electrospun fibers was through their effect on the viscosity of solution. In addition, we found that the diameter of electrospun fibers depended on the solution and processing parameters.

Abstract: Graphene film on silicon carbide is considered to be promising material for high-frequency vacuum nanoelectronics. However, the possibility of graphene application in this area is still poorly understood. We have carried out the simulation of the electric field distribution in interelectrode gap of the anode-cathode system pointed field emission cathode based on silicon carbide with graphene film on its surface subject to the rounding-off radius of the top, interelectrode gap, height and cathode forming half-angle of the cone opening by the finite element method. The influence of constructional parameters on the electric field strength in the test structure was analyzed. It is shown that the values of rounding-off radius of the cone point and interelectrode distance has the biggest influence on the electric field in the investigated structure. Changing of the height and cathode forming half-angle of the cone opening does not lead to a significant increase or decrease of the electric field value.

Abstract: With the increase of urban electromagnetic radiation source, electromagnetic environment pollution which poses a threat to the health of the residents is increasingly worse, there exists a controversy to the safety limit. In order to master the basic information about urban electromagnetic radiation source of major cities in Jilin, the statistical analysis of environmental comprehensive field monitoring data is conducted in Jilin province’s major cities, Changchun, Yanji and Siping ,the result shows that the electric field intensity of the environmental electromagnetic radiation in three cities is below China electromagnetic radiation safety standard. Then according to the research situation at home and abroad , combining the practical situation of Jilin province, this article discusses the protection standard of environmental electromagnetic radiation and provides the suggested values of the safety threshold limit of electromagnetic radiation .

Abstract: Corona cage six bundle conductors corona loss were measured, and corona onset electric field was obtained. The IEC 61284 standard was adopted as altitude correction. And add to this, exponential form and linear form altitude correction formulae were adduced. The results show that, exponential form altitude correction formulae calibration error and dispersion are less, and the adjustment effect is better; for convenient engineering application, linear correction formulae can be adopted; for estimation in the rough, sea level as base, as altitude increases every 1000m, conductor corona onset electric field decreases about 7%.

Abstract: In order to analyze the partial discharge of void defect discharge in solid insulator, for the PD problems that at home and abroad simulation model can’t objectively reflect the physical process of partial discharge. Based on classical three capacitor equivalent-circuit model, the change of the electric field intensity and the voltage as size of the air void differs is studied. The influence of the air void geometry properties of partial discharge is analyzed. By comparing the results of the simulation model and its results and existing research results, the correctness of the circuit simulation model is verified.

Abstract: The problem of a piezoelectric screw dislocation emitted from a blunt crack is dealt with in this paper. For an arbitrary distribution of the residual dislocation, the series-form solutions are derived. The results show that the force acting on the dislocation decreases with the value of the dielectric constant within the crack increasing. And the increase of the dielectric constant within the crack helps dislocation emission effectively.

Abstract: Since in their tenders for subway fire alarm system contracts some fire detector manufacturers recently claimed that the RF electromagnetic field strength to which their products can resist is much higher than the requirements of the relevant national technical standards on fire, we have conducted tests on the RF electromagnetic field strength around the fire detectors installed on the platform of a number of selected subway stations in Guangzhou, and the performances of the electromagnetic radiation analyzer used for the tests are strictly in compliance with the specified use conditions for fire detectors installed on the platform in subway stations. The test results show that the RF electromagnetic field strength applied in the RF radiated immunity test as specified in relevant national standards conforms to the current application conditions.

Abstract: Global System for Mobile Communications (GSM) and other telecommunication technologies are now ubiquitous worldwide. There has been considerable increase in the radiofrequency (RF) radiation exposure of the public from GSM and telecommunication transmitting and receiving antennas. If the RF radiation emanating from these devices exceeds internationally recommended limits it may pose health risk to the public. There is, therefore, the need for database of RF distribution levels in Nigeria for safety assessment. In this study, the power density of mobile phone base station masts in Benin City, Edo State, Nigeria was measured and analyzed to check if it is within the public standard recommended by International Commission on Non-Ionizing Radiation Protection (ICNIRP). A total of forty (40) mobile phone base station masts were studied and their power density (mW/m²), magnetic field strength (A/m) and electric field strength (V/m) were determined by means of a digital Electrosmog meter, model MECO 9810 RF covering the frequency range 10 MHz 8 GHz. The measurements were made at the base of the masts and at distances 25, 50, 75 and 100 m respectively from the base of the masts. The results obtained show that the mean power density, magnetic field strength and electric field strength range from 0.589 ± 0.198 to 127.718 ± 11.301 mW/m², 0.318 ± 0.056 to 4.166 ± 2.041 A/m and 0.934 ± 0.139 to 11.745 ± 3.427 V/m. The measured and calculated power density values were compared and found to indicate high positive correlation. Also the values of the power density obtained in this study at the different distances and locations were found to be far below the ICNIRP public exposure limits ranging from 2000 10000 mW/m² in the frequency range of 10 MHz 300 GHz.

Abstract: Electrorheological fluid (ERF) is a new kind of smart materials, which has a great deal of market value and broad application prospects. To meet the needs of the ERFs performance testing, design and produce of the ERF's performance test system are based on the relationship of the apparent viscosity, shear stress and electric field strength. Select the NDJ-8S digital viscometer, high voltage DC power supply, liquid container, and other parts to constitute the ERFs performance test system after considering the relationship of the apparent viscosity, shear stress, shear rate and electric field strength. The system has potentials to control voltage, change velocity, change the distance between the parallel panels, and test the yield stress of the ERF, shear stress, viscosity and other parameters. The study introduces the hardware and software device, the related experiments, and obtains the relationship of the viscosity, rotational speed, voltage, and plate gap.

Abstract: On the copper substrate the DLC films is preparated by plasma elcctrodeposition in methanol aqueous solution. The plating solution composition: alcohol water proportion is 4:1, the additive KCl content is 3g/L and the AlCl3 is trace amounts. The influence of the current density and the electrode spacing to the electrode surface bubble zone thickness, uniformity and stability are discussed in the article. The film surface morphology is observed by scanning electron microscopy (SEM). The thickness of the film D=30, 350, 410 and 380 nm. The deposition rate K=150, 175, 205 and 190 nm/h. The polycrystalline structure of the film can be observed through the X-ray diffraction (XRD) pattern., the characteristic peak of the (111),(200) and (220) crystal plane are observed at 2θ= 43.9°,50.9°and75.3°. The high carbon content is observed by EDX analysis.