Dental enamel is the structure which is first exposed to the attack of dental caries, and the success or failure of this attack depends on many factors, among them the chemical nature and structure of the enamel. Some authors (Pincus, 1939; Gottlieb, 1947) go so far as to postulate that the caries process is initially a proteolytic one. In this connexion the nitrogenous material of enamel is of...

We report photoluminescence (PL) studies of high-quality Zn 1~x Be x Se "lms grown by molecular beam epitaxy (MBE) on GaAs substrates by use of a novel growth method of Be}Zn co-irradiation before the growth of a thin ZnSe bu!er layer. Samples show double-crystal X-ray linewidth as narrow as 23 arcsec. Low-temperature (13K) PL of undoped samples showed free exciton emission, which de"ned the ba...

In this paper, the effect of pressure, temperature and impurity on the energylevels, binding energy, linear and nonlinear optical properties of a modified Gaussianquantum dot are studied. In this regard, the finite element method is employed to solvethe single electron Schrodinger equation in the effective mass approximation with andwithout impurity at the center of the dot. In addition, the en...

Abstract This paper presents the first result using nitrogen-seeded exhaust feedback control of NII impurity emission front in TCV. The position is consistently located below its commonly used CIII counterpart, indicating representative a colder plasma region. We demonstrate for two cases: (a) nitrogen seeding as sole actuator, and (b) deuterium fueling an actuator while injecting small amount ...

We report measurements of the inelastic neutron scattering spectrum for the anisotropic intermediate valence system Yb2Rh3Ga9. Calculations for the Anderson impurity model with crystal field terms within an approach based on the non-crossing approximation have been performed for the inelastic neutron scattering spectrum as well as other thermodynamic quantities. These results corroborate the im...

The polymerization by radiofrquency (RF) plasma of different monomers (methyl methacrylate (MMA), tetraglyme and 2-hydroxyethyl methacrylate (HEMA)) has been carried out. The plasma gas was investigated by optical emission spectroscopy (OES) in the UV-vis wavelength rang. The excited species formed in the plasma were identified for the different monomers. From computer simulations of the ro-vib...

To analyze the local structure and/or chemical states of boron atoms in boron-doped diamond, which can be synthesized by the microwave plasma-assisted chemical vapor deposition method (CVD-B-diamond) and the temperature gradient method at high pressure and high temperature (HPT-B-diamond), we measured the soft X-ray emission spectra in the CK and BK regions of B-diamonds using synchrotron radia...

We present measurements of spin relaxation times (T1, T1ρ, T2) on very shallow (≲5  nm) nitrogen-vacancy centers in high-purity diamond single crystals. We find a reduction of spin relaxation times up to 30 times compared to bulk values, indicating the presence of ubiquitous magnetic impurities associated with the surface. Our measurements yield a density of 0.01-0.1μB/nm2 and a characteristic ...

Natural gas consumption has grown from 5.0 trillion cubic feet (TCF) in 1949 to 27.0 TCF in 2014 and is expected to be ;31.6 TCF in 2040. This large demand requires an effective technology to purify natural gas. Nitrogen is a significant impurity in natural gas and has to be removed since it decreases the natural gas energy content. The benchmark technology to remove nitrogen from natural gas i...