The top-down methodology and CAD tools are important in development of electronic circuits. Mainly when design is in high level of abstraction and many levels of representation can be used to modeling the electron ic circuits. Th is way is necessary to use a tool to execute the synthesis of models, i.e ., changing a representation in high level of abstraction in another in lower level. This pap...

Background: Jaw bone quality plays an essential role in treatment planning and prognosis of dental implants. Regarding several available methods for bone density measurements, they are not routinely used before implant surgery due to hard accessibility.Objective: An in vitro investigation of correlation between average gray scale in direct digital radiographs and Hounsfield units in CT-Scan pro...

three high-silica mordenite zeolites differing in sio440, ratio were prepared by direct synthesis without using any template. the products si02/a120, ratio is influenced by the starting gel composition. this ratio is increased upon ion-exchange with nh,cl and subsequent calcination to prepare protonic mordenite. the protonic mordenites with si02/a1203ra tios of 14.6,29.2 and 34.6 were character...

Recent research in Phase-Sensitive Optical Time Doman Reflectometry (ϕ-OTDR) has been focused, among others, on performing spatially resolved measurements with various methods including the use of frequency modulated probes. However, conventional schemes either rely phase-coded sequences, involve inflexible generation probe modulation or mostly employ simple linear (LFM) pulses which suffer fro...

DDFS (Direct Digital Frequency Synthesizer) is a new technique of frequency synthesizes which introduces the advanced digital processing theory into frequency synthesis. A direct digital frequency synthesizer is composed of a phase accumulator, an adder, an ROM for wave pattern saving, a D/A converter and a LPF (low pass filter). With the rapid development of VLSI, the speed of algorithm is req...