Versatile Active Biquad Based on Dual-Output Second-Generation Current Conveyors

A universal active biquad based on the dual-output second-generation current-conveyor (CCII±) is presented. The circuit uses only six CCII± and can, simultaneously, support three mixed-mode transfer functions and five current-mode transfer functions. The circuit uses grounded resistors and capacitors and enjoys independent grounded-element control of the filter parameters

Chemo-Mechanical Approach to Improve Repair Bond Strength of Denture Teeth

Background. Detachment of acrylic teeth from denture base material is a common complication in dentistry which accounts for 26–30% of repair cases. This study aimed to evaluate the effect of alumina-blasting, silane coupling agent, and thermal cycling on the shear bond strength of repaired teeth to denture base. Materials and Methods. Specimens (140) of repaired teeth to denture bases were fabricated and divided into 14 groups: 7 groups before thermal cycling and 7 groups after thermal cycling (n = 10). The groups were divided according to surface treatment into no treatment (control), treatment of the base (B), the tooth (T), or both (BT). Each group was further subdivided according to the surface treatment method into alumina-blasting or alumina-blasting and silane coupling agent. After treatment, acrylic discs and teeth were fixed in a jig, and the repair procedure was done. Half the specimens were thermally cycled. Shear bond strength was measured using a universal testing machine. ANOVA and Tukey HSD tests were performed at α = 0.05. Results. Surface treatment significantly improved the bond strength compared to the control group P<0.001. Comparing surface treatments, alumina-blasting with silane coupling agent treatment resulted in significantly higher strength compared to alumina-blasting alone P<0.001. The BT group treated with alumina-blasting and silane coupling agent showed the highest significant shear bond strength (23.91 ± 0.96 MPa) P<0.001. Significant drop in strength value was observed in all groups after thermal cycling P<0.004 except the BT group treated with alumina-blasting P=0.096. Conclusion. Surface treatment using alumina-blasting with silane coupling agent for denture base and tooth increased repair strength

Damage in crystalline silicon by swift heavy ion irradiation

We have studied damage of crystalline Si surfaces induced by electronic energy loss of swift heavy ions with an electronic stopping power of up to S e = 12 keV/nm. Scanning tunneling microscope images of the surface after irradiation under perpendicular as well as glancing angles of incidence showed no surface damage. We have performed theoretical calculations for the damage threshold within the two temperature model, resulting in View the MathML sourceSeth=8 keV/nm as the minimum stopping power to create a molten zone. We investigate the respective influence of the electron–phonon coupling, of the criterion at which the damage occurs and a possible effect of ballistic electrons. We show that the latter has the strongest effect on the calculated damage threshol

Electronic sputtering: angular distributions of (LiF)

A combination of imaging techniques (XY) and time-of-flight (TOF) spectroscopy was used to measure the complete velocity vector of sputtered positive secondary ions in collisions of Kr33+ (10.1 MeV/u) with well prepared LiF single crystals in the electronic stopping regime. The angular distributions of (LiF)nLi+ clusters become broader with increasing cluster size n. This could be an indication of contributions from different ejection mechanisms. The experimental secondary ion angular distributions can be fitted by a simple cosine function of the type N(θ) = A cosm(θ), but it does not reproduce the shape of the jet-like structure observed for the emission of neutral LiF particles perpendicular to the ion beam. Therefore, the cluster emission hypothesis does not explain in a simple way the observed narrow jet

Electronic sputtering of LiF by Krypton (10 MeV/u): size dependent energy distributions of Li+(LiF)n clusters

International audienc

Electronic sputtering: angular distributions of (LiF)nLi+ clusters emitted in collisions of Kr (10.1 MeV/u) with LiF single crystals

International audienc