Constant Lg Research Articles

The thermal decomposition of silver dinitramide AgN(NO2)2

Silver dinitramide AgN(NO2)2 was prepared, and its structure was characterized by UV–Visible absorption spectra, Fourier transform infrared (FT-IR) spectra and Fourier transform Raman spectra. Its thermal decomposition process was investigated by differential scanning calorimetry and thermogravimetric analysis coupled with the gas analysis by FT-IR (EGA-FT-IR). The intermediate and final products of thermal decomposition were analyzed by FT-IR, Raman spectra and X-ray diffraction. Kissinger method and Ozawa methods were used to calculate apparent activation energy Ea, the pre-exponential constant lg A and linear correlation coefficient r. The results showed that the degradation process of AgN(NO2)2 could be divided into two stages. The first one with a mass loss of 21.86 % took place in 408–483 K, in which N2O was released and the intermediate product of thermal decomposition was AgNO3. The second stage with a mass loss of 28.24 % occurred in 483–800 K. In this process, gases NO2 and O2 were evolved and Ag was the final product of thermal decomposition. Kissinger method results: Ea = 66.59 kJ mol−1, lg A = 7.21 min−1 and r = 0.9913. Ozawa method results: Ea = 70.53 kJ mol−1, r = 0.9987.

Formation of the intensively fluorescent mixed-ligand complex of Zr(OH)3+ with 3,5,7,2′,4′-pentahydroxyflavone in the presence of fluoride

The interaction between Zr(IV) and morin in the presence of fluoride has been found to be accompanied by the formation of the mixed-ligand complex Zr(OH)3(H4R)(F)−. The stability of the complex can be characterized by the concentration affinity constant lg Кα = 20.67 ± 0.04.

Spectroscopic speciation and structural characterisation of uranyl(VI) interaction with pyridine carboxylic acid N-oxide derivatives

Spectroscopic speciation of U(VI) solutions holding pyridine carboxylic acid N-oxides in a range pH 2.3–4.5 results in the single component spectrum of the U(VI) isonicotinic acid N-oxide complex. The molar absorption is 14 ± 2 L mol −1 cm −1 at 415.4 nm. The formation constant lg K UL = 2.1 ± 0.2 ( k = 2) is derived from solution modelling and by multivariate chemometric analysis. The first crystal structure analysis of a U(VI) pyridine carboxylic acid N-oxide revealed a sheet-like structure where the isonicotinic acid N-oxide binds to the uranyl(VI) both bidentately by the carboxylate group and monodentately by the N–O group. The single component spectrum of the [UO 2L] + (where L − is isonicotinate N-oxide) is compared to the small number of other U(VI) single ligand species. The comparison revealed the possible pitfalls of U(VI) spectroscopic speciation close to the pH region where U(VI) hydrolysis starts to interfere. On basis of the results for U(VI)–L coordination and physicochemical properties of the pyridine carboxylic acid N-oxides some conclusions could be drawn on the likely behaviour of nicotinic acid N-oxide and picolinic acid N-oxide. For the former, complex formation in a narrow range of pH and U(VI) concentrations close to the hydrolysis range of U(VI) might reveal thermodynamic data. In the case of picolinic acid N-oxide, additional experimental evidence is required to characterize suitable conditions.

Analysis of Subthreshold Behavior of FinFET using Taurus

This paper investigates the subthreshold behavior of Fin Field Effect Transistor (FinFET). The FinFET is considered to be an alternate MOSFET structure for the deep sub-micron regime, having excellent device characteristics. As the channel length decreases, the study of subthreshold behavior of the device becomes critically important for successful design and implementation of digital circuits. An accurate analysis of subthreshold behavior of FinFET was done by simulating the device in a 3D process and device simulator, Taurus. The subthreshold behavior of FinFET, was measured using a parameter called S-factor which was obtained from the ln(IDS) - VGS characteristics. The value of Sfactor of devices of various fin dimensions with channel length Lg in the range of 20 ㎚ - 50 ㎚ and with the fin width Tfin in the range of 10 ㎚ - 40 ㎚ was calculated. It was observed that for devices with longer channel lengths, the value of S-factor was close to the ideal value of 60 ㎷/dec. The S-factor increases exponentially for channel lengths, Lg < 1.5 Tfin. Further, for a constant Lg, the S factor was observed to increase with Tfin. An empirical relationship between S, Lg and Tfin was developed based on the simulation results, which could be used as a rule of thumb for determining the S-factor of devices.

The geopotential value W 0 for specifying the relativistic atomic time scale and a global vertical reference system

The TOPEX/Poseidon (T/P) satellite alti- meter mission marked a new era in determining the geopotential constant W0. On the basis of T/P data during 1993–2003 (cycles 11–414), long-term variations in W0 have been investigated. The rounded value W0 = 62636856.0 ± 0.5) m2s−2 has already been adopted by the International Astronomical Union for the definition of the constant LG = W0/c2 = 6.969290134 × 10−10 (where c is the speed of light), which is required for the realization of the relativistic atomic time scale. The constant LG, based on the above value of W0, is also included in the 2003 International Earth Rotation and Reference Frames Service conventions. It has also been suggested that W0 is used to specify a global vertical reference system (GVRS). W0 ensures the consistency with the International Terrestrial Reference System, i.e. after adopting W0, along with the geocentric gravitational constant (GM), the Earth’s rotational velocity (ω) and the second zonal geopotential coefficient (J2) as primary constants (parameters), then the ellipsoidal parameters (a,α) can be computed and adopted as derived parameters. The scale of the International Terrestrial Reference Frame 2000 (ITRF2000) has also been specified with the use of W0 to be consistent with the geocentric coordinate time. As an example of using W0 for a GVRS realization, the geopotential difference between the adopted W0 and the geopotential at the Rimouski tide-gauge point, specifying the North American Vertical Datum 1988 (NAVD88), has been estimated.

RegionalLgattenuation for the continental United States

AbstractMeasurements of the Fourier amplitude spectra of Lg phases recorded at high frequency (0.5 to 14.0 Hz) by broadband seismic stations are used to determine regional attenuation relationships for southern California, the Basin and Range Province, the central United States, and the northeastern United States and southeastern Canada. Fourier spectral amplitudes were measured every quarter octave from Lg phases windowed between 3.0 and 3.7 km sec−1 and recorded in the distance range of 150 to 1000 km. Attenuation at each frequency is determined by assuming a geometrical spreading exponent of 0.5 and inverting for Q and source and receiver terms. Both southern California and the Basin and Range Province are well described by low Lg Q and frequency-dependent attenuation. Lg spectral amplitudes in southern California are fit at low frequencies (0.625 to 0.875 Hz) by a constant Lg Q of 224 and by a frequency-dependent Lg Q function Q = 187−7+7f0.55(±0.03) in the frequency band 1.0 to 7.0 Hz. The Basin and Range Province is characterized by a constant Lg Q of 192 for frequencies of 0.5 to 0.875 Hz and by the frequency-dependent Lg Q function Q = 235−11+11f0.56(±0.04) in the frequency band 1.0 to 5.0 Hz. A change in frequency dependence above 5.0 Hz is possible due to contamination of the Lg window by Pn and Sn phases. Lg spectral amplitudes in the central United States are fit by a mean frequency-independent Lg Q of 1291 for frequencies of 1.5 to 7.0 Hz, while a frequency-dependent Lg Q of Q = 1052−83+91(f/1.5)0.22(±0.06) fits the Lg spectral amplitudes for the northeastern United States and southeastern Canada over the passband 1.5 to 14.0 Hz. Attenuation measurements for these areas were restricted to frequencies &amp;gt;1.5 Hz due to larger microseismic noise levels at the lower frequencies.

New Time Scales: Removing Ambiguities

The new (1991) IAU recommendations on reference systems and time scales are based completely on general relativity. But the metric forms determining the corresponding reference systems are specified in these recommendations not sufficiently definitive to take into account non-geodesic accelerations in the motion of the geocentre or topocentre, to distinguish between relativistic dynamically or kinematically non-rotating systems and to exclude a possible ambiguity in the time scales due to the relativistic coordinate gauge. There is a hidden ambiguity in the relativistic definition of the geocentre due to the difference bewteen Newtonian-type and Blanchet-Damour multipole moments used, respectively, in Brumberg-Kopejkin (Brumberg and Kopejkin, 1989; Kopejkin, 1991a; Brumberg et al., 1993; Klioner, 1993; Klioner and Voinov, 1993) and Damour-Soffel-Xu (1991-1994) approach to construct relativistic hierarchy of reference systems. In using TAI as physical realization of TT one should specify the constant LG(Fukushima, 1994) once for ever not introducing the relativistic ill-defined notion of the geoid (Kopejkin, 1991b). It might be reasonable not to separate this constant at all (as having no sense for moving clocks on the surface of the Earth or in the circumterrestrial space) and to use TAIM as physical realization of TCG itself relating TCG directly with the observer’s proper time avoiding the intermediate scale TT (Brumberg, 1992).