1,720,967 research outputs found
Effects of a radiated emission test site on a receiving antenna scattering parameters
No full textThe effects of a radiated emission test site on the
scattering parameters of a measurement antenna are here
investigated. To the purpose, experiments are conducted
measuring the input impedance of a reference loop antenna in
different test sites and varying the antenna position from the
ground floor. The purpose is to investigate how the site
characteristics may influence the antenna scattering parameters and consequently the accuracy in electric field measurements.
The analysis is finally extended to the case of a standard 30-200 MHz biconical antenna
Prove di emissione irradiata EMC: misure di campo magnetico nel range 30 a 100 MHz
No full textIn uqesto lavoro sono raccolti dei risultati sperimentali finalizzati ad evidenziare
alcune criticità non trascurabili nella misurazione e
nell’esito dei test di emissione irradiata della compatibilità elettromagnetica nella
banda di frequenze 30-100 MHz
A New Proposal for the Uncertainty Evaluation and Reduction in Air Electrostatic Discharge Tests
No full textThe technique used in air electrostatic discharge (ESD) immunity tests to approach the generator tip to the equipment under test is here dealt with. Specifically, the uncertainty contribution associated to the measurement technique is analyzed in depth. To this aim, a number of simulations and experiments are carried out by means of a proper test bed, which includes a purposely-developed slide system. Through this system, the effects of different "type A" uncertainty contributions are compared and the ESD repeatability is assessed. Taking into account the "type B" uncertainty contribution too, the purpose of the work is to provide an original and efficient proposal for improving the uncertainty evaluation in air ESD tests
Transformation of Streptococcus sanguis Challis with a plasmid of Streptococcus pneumoniae
No full textThe present work is concerned with plasmid transformation of Streptococcus sanguis strain Challis with derivatives of pDP1/pSMB1, the only plasmid found to occur naturally in Streptococcus pneumoniae. Two recombinant plasmids derived from the cryptic pSMB1 were used: pDP27 (4.5 kb) conferring resistance to chloramphenicol (Cm), and pDP28 (7.8 kb), a shuttle plasmid, conferring resistance to Cm in Escherichia coli, and resistance to erythromycin (Em) in pneumococcus. It could be shown that pSMB1 can replicate in S. sanguis; in fact, Challis strain V288 was transformed to Cm-resistance and to Em-resistance by pDP27 and pDP28 respectively.
Shuttle plasmid pDP28 can transform S. sanguis both when isolated from pneumococcus and from E. coli, albeit with a different efficiency. The low frequency of transformation observed when pDP28 was isolated from E. coli DH1 (recA) was shown to be due to lack of multimeric forms of the plasmid in the DNA preparations obtained from this strain. When pDP28 was isolated from E. coli C600 (RecA+), multimeric forms were present, and transformations of S. sanguis was more efficiency Using pDP28 as vector in cloning experiments, where S. sanguis was the host of the recombinant DNA molecules, treatment of the vector with alkaline phosphatase inhibited the recovery of recombinant clones
Transformation as a tool for studying the epidemiology of tet determinants in Streptococcus pneumoniae
No full textTransformation of pneumococcus was used to detect homology among tetracycline resistance determinants of clinical isolates of Streptococcus pneumoniae. A strain of pneumococcus containing a mutated tet determinant (tet-3), of class M, integrated into the chromosome was used as a recipient in transformation experiments, where donor DNA was from the tetracycline resistant isolates. 34/34 strains appeared to have tet determinants homologous to tet-3 (i.e. tet M). Still using transformation it was possible to determine that the tet-3 transforming activity of DNA from Tn916 and S. pneumoniae BM6001 was contained in a 5 kb HincII fragment. For this purpose a transformation technique where donor DNA was directly taken from low melting point agarose gels was standardized and used
Time-Domain Characterization of the Surge, EFT/Burst, and ESD Measurement Systems
No full textA simple, well-established (although in applications different from electromagnetic compatibility), amenable to direct interpretation, and inexpensive method for the time-domain characterization of the measurement systems used for the calibration of the standard impulse generators for immunity tests is presented. The validity and general applicability of the method is demonstrated through an extensive experimental investigation
Cloning of an erm gene from the chromosome of a clinical isolate of Streptococcus pneumoniae
No full text
Improved adapters for the accurate calibration of LISN input impedance
No full textThe paper deals with the accurate calibration of LISN impedance at the EUT port, focusing on the effects of parasitic parameters at the EUT side and their effects on calibration. The goal is to improve the calibration accuracy and repeatability by adopting a standardized external adapter, used to connect the measurement system to the LISN. Different models are analysed, both theoretically and experimentally, through meaningful experimental examples
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