Polish Tele and Radio Research Institute

Warsaw, Poland
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Koscielski M.,Polish Tele and Radio Research Institute | Sitek J.,Polish Tele and Radio Research Institute
2016 6th Electronic System-Integration Technology Conference, ESTC 2016 | Year: 2016

As the miniaturization of the devices is progressing the chips have to have more functions and cover less space. One of the methods to achieve this goal is usage of Package-on-Package (PoP) technique. In this paper the influence of used soldering profiles on joints reliability will be presented. The boards had ENIG as final coating. The reliability was checked by the monitoring of resistance as the boards were tested in climatic chamber at-40°C to 105°C for 20 minutes at each chamber. IMC at the beginning of the test and after is presented. © 2016 IEEE.

Lesniewska E.,University of Lodz | Lisowiec A.,Polish Tele and Radio Research Institute
IEEE Transactions on Power Delivery | Year: 2016

High accuracy is required from devices operating in the measuring and protection systems of transmission lines during the transformation of signals. Their immunity to external fields is very important because it has a direct influence on the proper functioning of the protection system. In this paper, the electromagnetic current-to-voltage transducers, with coils designed and manufactured using a multilayer high-density interconnect printed-circuit board technology, are presented. The analysis of the influence of the external magnetic field caused by other devices on the proper functioning of the current-to-voltage transducer has been presented. The analysis of the electromagnetic-field distributions has been carried out using the 3-D field-circuit method based on the finite-element numerical method. The magnetic-field distributions and the induced secondary voltages for several different applications have been presented. The results have been compared with tests of real-life models. © 2015 IEEE.

Slusarek B.,Polish Tele and Radio Research Institute | Jankowski B.,Polish Tele and Radio Research Institute | Sokalski K.,Czestochowa University of Technology | Szczyglowski J.,Czestochowa University of Technology
Journal of Alloys and Compounds | Year: 2013

In this paper, we consider a new way to choice values of technological parameters, such as compaction pressure and hardening temperature which are required during preparation of soft magnetic composites. The novel approach based on an optimization of power loss in soft magnetic composites. The power losses have been measured in Somaloy 500 samples for a wide range of frequency and magnetic induction. These samples have been prepared under a wide range of compaction pressures and hardening temperatures. The power loss characteristics have been derived by assuming that investigated samples obeyed the scaling law. Agreement obtained between the experimental data and the scaling theory has confirmed this assumption. Moreover, the experimental data of the given sample have been collapsed to a single curve which represented measurements for all values of frequency and magnetic induction. The scaling transforms the loss characteristics from the two dimensional surfaces to the one dimensional curves. The samples were produced according to two methods: for different pressures with constant temperature and at different temperatures with constant pressure. In both cases the power losses decrease with increasing pressure and with increasing temperature. The reduction of power losses with increasing compaction pressure and hardening temperature respectively, stops for their certain critical values. Above these values, the power losses increase suddenly. The aforementioned, the critical pressure and the critical temperature are sought after solutions for optimal values. In order to reduce the parameters values set, the limit curve has been derived in the pressure-temperature plane. This curve constitutes a separation curve between the parameters values corresponding to high and low losses. © 2013 Elsevier B.V. All rights reserved.

Niemczewski B.,Polish Tele and Radio Research Institute
Ultrasonics Sonochemistry | Year: 2014

When measuring cavitation during cooling of thermally degassed water cavitation maxima are frequently observed at various temperatures. Relations between this phenomenon and frequency and power of ultrasounds as well as air content in water have been examined. It was found out that the secondary water regassing with air is the reason. © 2013 Elsevier B.V. All rights reserved.

Kardys W.,Polish Tele and Radio Research Institute | Milewski A.,Polish Tele and Radio Research Institute
Acta Physica Polonica A | Year: 2015

The paper presents results of theoretical analysis as well as practical measurements of effciency in ultrasonic welding system with main focus on ultrasonic generator. Through analysis and tests were performed using 3 kW 20 kHz Sonic Blaster ultrasonic generator manufactured by ITR. Special equipment was used to perform accurate measurements of input and output power of such generator since an output signal of the ultrasonic generator has high voltage amplitude up to 3 kV and frequency of 20 kHz. Artificial load able to dissipate up to 6 kW of continuous power was designed to simulate ultrasonic transducer. Power measurements were performed on the mains supply of the generator using accurate true RMS power meter and load side measurements were performed using specially built power metering system able to measure high voltage 20 kHz signals based on calibrated high voltage resistive divider and high frequency current transducer.

Niemczewski B.,Polish Tele and Radio Research Institute
Transactions of the Institute of Metal Finishing | Year: 2011

The purpose of the work was to compare cavitation intensities of solutions of various salts with cavitation of water in order to identify that some solutions cavitate more intensely than water and this might be applied in practice. Cavitation intensities at an ultrasonic frequency of 26 kHz in tap water and in thirty-five 3% aqueous solutions of selected inorganic salts were compared, as well as in tap water and in twenty-four 3% solutions of inorganic salts at 38 kHz and at 50°C. It was found that at 38 kHz many salt solutions cavitate more intensely than water and some of them cavitate considerably more intensely. At 26 kHz only one such salt was found. At both frequencies and 50°C, some of salt solutions cavitate much less intensely than water. © 2011 Institute of Metal Finishing.

Niemczewski B.,Polish Tele and Radio Research Institute
Transactions of the Institute of Metal Finishing | Year: 2010

Maximum cavitation intensities at 60°C of 3% aqueous solutions of chemical substances used as components of media for ultrasonic cleaning in aqueous alkaline solutions have been measured. The maximum cavitation intensities for these substances reached in 25 and 40 kHz cleaners have been compared. © 2010 Institute of Metal Finishing.

Czopik A.,Polish Tele and Radio Research Institute
Welding International | Year: 2013

This paper presents the application of an electron beam as a tool for welding metals, and discusses new opportunities for its use based on the use of a computer control system. © 2013 Copyright Taylor and Francis Group, LLC.

Sitek J.,Polish Tele and Radio Research Institute | Koscielski M.,Polish Tele and Radio Research Institute
Circuit World | Year: 2014

Purpose - The purpose of this paper is to investigate the influence of different micro additives to new compositions of electrically conductive adhesives (ECA) on their printing properties as well as electric parameters expressed in resistivity of joints cured in low temperatures and obtain recommendations for elaboration of ECA appropriate for printing electronic applications. Design/methodology/approach - The three different types of silver flakes and two types of micro powders were added to basic matrix of ECA to create ECA composition for investigation. The ECA were printed via stencil on elastic substrate creating the special designed samples which next were cured in 25°C, 50°C or 80°C. The SEM with EDS analysis was utilized for assessment of shapes and sizes of the input materials for ECA. The microscopic observation and resistivity measurements of samples by four-probe method were used for assessment of the influence of ECA compositions on prints quality as well as on electric parameters of adhesives joints. Findings - The results show that the quality of the prints made with the use of elaborated adhesive compositions is related mainly with the amount and type of filler used in ECA. The electrical properties of joints were dependent from type of silver flakes and amount of micro-additives as well as curing temperature. Research limitations/implications - It is suggested that further studies are necessary for the confirmation of the practical application, especially of the mechanical and reliability properties of the joints obtained with the use of final composition of the elaborated ECA. Originality/value - The presented results of analyses provide information regarding the correlation between the composition of ECA, properties of elements creating them and the results of printing and electric parameters of joints produced of them. It showed positive impact of small carbon micro powder addition both on printing results and resistivity of joints. It pointed out also that the purity of silver components of ECA influences significantly on resistivity of ECA's joints. It is valuable information for ECA's designers as well as end-users, from the practical point of view. © Emerald Group Publishing Limited.

Niemczewski B.,Polish Tele and Radio Research Institute
Transactions of the Institute of Metal Finishing | Year: 2012

It is known from the practice of ultrasonic cleaning that in most cases the increase in concentration of an alkaline solution used for ultrasonic cleaning leads to lower cavitation intensity, a primary causative agent of efficient ultrasonic cleaning. On the other hand, there is no information as regards cavitation intensity trends with increasing concentration of acid solutions. In order to check the influence of concentration (from 1 to 7% w/w) on cavitation intensity, the maximum cavitation of three acids (orthophosphoric, tartaric and citric) was measured under the same conditions at 50 and 60uC in ultrasonic cleaners operating at 34, 35?5, 36?7, 40 and 44 kHz. The resulting data did not confirm, unlike most alkaline cleaning solutions, that increasing the concentration of acid solutions above 3% w/w, the concentration most frequently used, reduced cavitation intensity. An exception was the operation of tartaric acid at 40 kHz. © 2012 Institute of Metal Finishing.

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