Papers by Keyword: PCB

Abstract: The paper described selection principle of the device, carried out a detailed analysis and the design of the diagram of the high-frequency transformer. At the same time, the PCB layout design was put forward. Experimental results show that the power supply would still be able to output stable DC in the case of grid voltage fluctuation and larger load disturbance, had the characteristic of good stability and high precision, all parameters can meet the system requirements.

Abstract: Three types of copper traces for PCBs were investigated: 1) 2.5 μm thin film lines (Ti;Cu;Ni) on aluminium and ceramic (Al₂O₃) substrates; 2) 2.5 μm thin film lines (Ti;Cu;Ni;Au) on ceramic (Al₂O₃) substrates; 3) 15 μm traces (Cu;Ni) on polyimide substrate for high density interconnection PCBs. The width of all types of traces was varying in the range of 100-500 μm. The set of temperature-current diagrams for different PCB scenarios are presented and analyzed. The temperature caused by Joule heating was measured using IR camera Flir A40 with macrolens. For different cases the current was set in the range of 0.1-3 A; the measured temperature was in the range of 20-140 °C. The close agreement between the results measured and simulated with ELCUT software tool was achieved.

Abstract: Polychlorinated biphenyls (PCBs) are Persistent Organic Pollutants (POPs). This experiment screened a halophilic bacterium from the deep sea sediments, which could grow at the salinity of 15%, and designated as B2.6. The cells of this strain were rod shaped, Gram negative, motile, could grow in pH range of 5.0-9.0, and temperature range 10-37°C. Growth of this bacterium in the presence of PCBs, as the sole source of carbon and energy. The ions of IA, such as Na⁺ and K⁺ could enhance the activity of PCBs-degrading enzyme, while the transitional metal ions, such as Co²⁺, Mn²⁺, Cu²⁺, Fe²⁺ and Fe³⁺ may inhibit it in a certain degree. The optimal temperature, pH value and concentration of NaCl for the PCBs-degrading enzyme were 25-35°C, pH 6-8 and 50 g·L^-1, respectively.

Abstract: This paper reports an 8-bit 1.72-Gsample/s TimeInterleaved analog-to-digital converter (TIADC) based on PCB with Field Programmable Gate Array (FPGA) technique. The system integrates two independent designed 8-bit 0.9-Gsample/s ADC chips in parallel, commercial FPGA and multi phase clock distributor circuit. In order to increase the systems performance, online calibration method is proposed to calibrate the mismatching errors in TIADC. The utilization of the FPGA is proven to be effective in removing the offset & gain mismatch; the clock distributor circuit is used as the time delay for each Sub-ADC chip to eliminate the sampling-time error. The hardware design features are also described in details. The ADC chip is fabricated in 0.35 um SiGe BiCMOS. Finally, experimental results reveal that the proposed system is capable to be operated up to 1.72GSps.Under this sampling frequency (1.72GHz), the system can achieve spurious free dynamic range (SFDR) which is larger than 40dBc. The effective code (ENOB) is lager than 5.5 bit from DC to Nyquist frequency and the power dissipation is 2.28 W.

Abstract: Sludge-coal water slurry (SCWS) can be produced by mixing coal water slurry (CWS) with sewage sludge according to differenct ratio. This paper focuses on the combustive feasibility of SCWS in a commercial circulating fluidized bed, and on the emission characteristics of polychlorinated biphenyls (PCBs) in flue gas fly ash and bottom ash during combustion of SCWS. The results indicated that incineration can do very well with the temperature 1000 degree, sludge coal water slurry (SCWS) can be effective in improving sludge incineration rate, if the proportion of sludge is 20%~30%,amounts of PCBs is relatively small in flue gas fly ash and bottom ash. So the best burning rate is 20%-30%. Although incineration flue gas fly ash and bottom ash emission standard don't have PCBs regulations, but since PCBs are toxic organic pollutants, it should be strictly regulated.

Abstract: The short-circuit phenomenon is one common error in the operation of electronic circuit. Short-circuit will cause the electrical components damage and the incorrect function in PCB. In general, the detection of short-circuit is performed by using the electrode probe to contact each pad in single PCB or the probe card in mass production of PCD. Due to the fast development of circuit layout, the size of IC with pads is getting smaller; therefore, it is much difficult to detect short-circuit in PCB by the pads-contact inspection. This paper presents a method to detect short-circuit area in PCB without the use of electrode probe, which employs the electromagnetic signals to sense and identify the change of electromagnetic induced by short-circuit. We design an electromagnetic sensing probe which comprises of an equivalent circuit to detect the change of electromagnetism in PCB, and employ an X-Y table for automatic positioning. Instead of tiny electrode probe manufacturing, the electromagnetic sensing method (ESM) is able to detect the short-circuit area inside the multi-layer PCB. In addition, the inspective module with ESM can be designed to be a portable instrument without the space limitation. The article shows the verification of proposed system with the scanning pitch is from 5 to 20 mil line width, the working distance of sensing probe is from 1 to 20 mm, and 4 layers PCB measurement. We also experiment the real case detection by using the ESM in PCB and display ESM can successful indicate the probable area of short-circuit.

Abstract: The purpose of this study is to propose an ultra compact 1×11 power splitter using a Polydiacetylene multimode interference coupler to improve its performance and decrease the dimension based on a contribution of Kerr nonlinear effect on modes propagation and interference. The power splitting is done with 11 outputs and small dimension. In fact, this is the first time that a power splitter is demonstrated at the length of less than 100µm with a large number of outputs. The device efficiency is studied in terms of insertion loss and uniformity. The simulation result shows extremely low uniformity and insertion loss due to the great small length.

Abstract: Various failures in electronic systems, particularly in the connections between the printed circuit board (PCB) and components, are due to mechanical shock and vibration. The vibration characteristic of a plug-in PCB in an airborne electronic case (AEC) was studied first by finite element modeling (FEM) and experimental techniques. The coupling method and torsional spring elements were used in FEM to better simulate the PCB’s realistic boundary condition. A reasonable correlation between simulation and test results was obtained. Since the fundamental frequency is one of the most important dynamic characteristics of PCB, the orthogonal design and variance analysis, as well as FEM method, were discussed subsequently to investigate the effects of different factors. Analysis results demonstrate a good correlation with current studies. Finally, a general design guideline was presented to maximize the PCB’s fundamental frequency.

Abstract: This paper analyses the actual applications demand of the real-time PCB production quality management information system for the electronic product manufacturing enterprises, has established functional model for the real-time PCB production and quality management information system, and has used of mathematical statistics and mathematical logic principles, methods to analyzed of PCB production quality information, which was collected in real-time, finally, has established a Quality Information System PCB, this system achieves the various production processes and product quality tracking and retroactively for PCB.

Abstract: This study aims to deal with the preparation of membrane-electrolyte assembly (MEA) of Pt/Ru/C nanocomposite as well as connecting to a direct methanol fuel cell and using PCB process packaging to test the efficiency of the DMFC. The components assembled in DMFC are including anode flow field plates, MEA and current collector.Using PCB boards for the anode flow field plates as well as the electicity collector plates and the type of flow field plate adopts serpentine flow field. For the efficiency of DMFC, liquid motors are used to press methanol mixed solution at specific temperature into DMFC. Besides, the cathode of DMFC adopts natural-breath method with air and uses DC electronic load to activate DMFC to investigate operating voltage and further to set constant voltage to measure current to calculate the efficiency of DMFC. Initial results of I-V curve show that self-developed MEA of Pt/Ru/C nanocomposite can enhance around 0.2% current density of DMFC after being assembled like commercial MEA