Synchrotron radiation-based x-ray photoemission spectroscopy was used to study the surface Fermi level position within the band gap for thin metal overlayers of Au, Al, Ni, Ti, Pt, and Pd on n–GaN and p–GaN. Nonequilibrium effects were taken into account by measuring the Fermi edge of the metal overlayer. There are two different behaviors observed for the six metals studied. For Au, Ti, and Pt,...

Di ver sos ti pos de po li es ti re no mo di fi ca dos fo ram ob ti dos atra vés da po li me ri za ção por en xer tia (graft poly me ri za ti on) de es ti re no na pre sen ça dos se guin tes mo di fi ca do res: co po lí me ro de eti le no-acetato de vi ni la (EVA); po li e ti le no de ba i xa den si da de (PE) e po li bu ta di e no (PB). Os mo di fi ca do res fo ram uti li za dos em se pa ra do...

A sample having stoichiometry Li[Ti(1.5)Ni(0.5)]O(4) has been synthesized to obtain a spinel structure. The resulting crystalline powder revealed a multiphase nature with spinel as the minor phase. The main phase is a new trigonal phase having a = 5.05910 (1), c = 32.5371 (1) A. The structure has been solved by direct methods working on a three-dimensional set of intensities obtained from a pre...

Resumen Actual men te se acep ta que la ad ven ti cia tie ne: un im por tan te rol fi sio ló gi co al de ter mi nar el ni vel de nu tri ción, oxi ge na ción, re pa ra ción ar te rial, re gu la ción de la va so mo tri ci dad, con trol de la pos car ga ven tri cu lar, con trol de la fun ción ar te rial, et cé te ra, a la vez que tie ne una im por tan te par ti ci pa ción en pro ce sos pa to ló gi...

Rela ti vis ti c line s tre ngth s have been co mllU ted fo r a la rge num be r of tra ns iti ons us ing Dirac wave fun c t io ns for the u ne-e lec tro n, h ydruge n-lik e io ns . As ex pec te d . th e results ind ica te th a t re la t ivi s ti c effect s a re qUlt es ma ll fo r l.ow s tages of io ni zatio n . Howeve r , in ge ne ral , th ey a lso re ma in s maJi thro ughout ,~ la rge p orti o...

In this article, the authors show that geometric asymmetry in the layout of tunnel diodes yields asymmetry in the current-voltage I-V relationships associated with these diodes. Asymmetry improves diode performance. This effect is demonstrated for polysilicon–SiO2–Ti /Au and for Ni–NiO–Ni tunneling structures. For a polysilicon–SiO2–Ti /Au asymmetric tunneling diode ATD , sensitivity and I-V cu...

INTRODUCTION The purpose of this study was to compare the frictional force (FF) generated by various combinations of self-ligating bracket (SLB) types, archwire sizes, and alloy types, and the amount of displacement during the initial leveling phase of orthodontic treatment, by using a custom-designed typodont system. METHODS Two passive SLBs (Damon 2 [D2] and Damon 3 [D3]), and 3 active SLBs...

AIM To compare ex vivo various parameters of root canal preparation using a manual technique and six different rotary nickel-titanium (Ni-Ti) instruments (FlexMaster, System GT, HERO 642, K3, ProTaper, and RaCe). METHODOLOGY A total of 147 extracted mandibular molars were divided into seven groups (n = 21) with equal mean mesio-buccal root canal curvatures (up to 70 degrees), and embedded in ...

The purpose of this study was to compare and evaluate the shaping ability of the three different Ni-Ti file systems used by undergraduate students. Fifty undergraduate students prepared 150 simulated curved root canals in resin blocks with three Ni-Ti file systems ProFile (PF), Manual ProTaper (MPT), Rotary ProTaper (RPT). Every student prepared 3 simulated root canals with each system respecti...