Static spread

The zero-volatility spread, also referred to as the Z-spread or static spread, is a measure of the spread that the investor would realize over the entire benchmark spot rate curve if the bond were held to maturity. Unlike the nominal spread, it is not a spread at one point on the yield curve. The Z-spread is the spread that will make the present value of the cash flows from the nongovernment bond, when discounted at the benchmark rate plus the spread, equal to the nongovernment bond s market price plus accrued interest. A trial-and-error procedure is used to compute the Z-spread. 

The zero-volatility or static spread is the spread that when added to the government spot rate curve will make the present value of the cash flows equal to the bond s price plus accrued interest. When spread is defined in this way, spread dnration is the approximate percentage change in price for a 100 basis point change in the zero-volatility spread holding the government spot rate curve constant. 

Initial Thickness Minimum Thickness Maximum Thickness Whole Wall Static Spreading... 

Therefore, the absorjDtion line is massively inlromogeneously broadened at low temperature. An inliomogeneous lineshape can be used to detennine the static or quasistatic frequency spread of oscillators due to a distribution of environments, but it provides no dynamical infonnation whatsoever [94, 95]. As T is increased to 300 K, the absorjDtion linewidth decreases and increases. At 300 K, the lineshape is nearly homogeneously broadened and dominated by vibrational dephasing, because fast dephasing wipes out effects of inliomogeneous environments, a well known phenomenon tenned motional narrowing [951. 

FIGURE 4 14 Electro static potential maps of methyl cation and ethyl cation The region of high est positive charge is more concentrated in CH3 and more spread out in CH3CH2 (The electrostatic potentials were mapped on the same scale in order to allow direct comparison )... 

Dussan EBV (1979) On the spreading of liquids on solid surfaces static and dynamic contact lines. Ann Rev Fluid Mech 11 371 00... 

An actual molecule is d Tiamic, not static. Electrons move continuously and can be thought of as being spread over the entire molecule. In a covalent bond, nevertheless, the distribution of electrons has the general characteristics shown by the static view in the figure. The most probable electron locations are between the nuclei, where they are best viewed as being shared between the bonded atoms. 

While the above refers mainly to the static limit, new effects come into play when a moving contact line, i.e. spreading, is considered. It has been observed experimentally that the contact angle of a moving contact line 0, the dynamic contact angle, deviates from the corresponding static value 0. As an example, for a completely wettable surface (i.e. 6(, = 0), a relationship of the form... 

The dynamic surface tension of a monolayer may be defined as the response of a film in an initial state of static quasi-equilibrium to a sudden change in surface area. If the area of the film-covered interface is altered at a rapid rate, the monolayer may not readjust to its original conformation quickly enough to maintain the quasi-equilibrium surface pressure. It is for this reason that properly reported II/A isotherms for most monolayers are repeated at several compression/expansion rates. The reasons for this lag in equilibration time are complex combinations of shear and dilational viscosities, elasticity, and isothermal compressibility (Manheimer and Schechter, 1970 Margoni, 1871 Lucassen-Reynders et al., 1974). Furthermore, consideration of dynamic surface tension in insoluble monolayers assumes that the monolayer is indeed insoluble and stable throughout the perturbation if not, a myriad of contributions from monolayer collapse to monomer dissolution may complicate the situation further. Although theoretical models of dynamic surface tension effects have been presented, there have been very few attempts at experimental investigation of these time-dependent phenomena in spread monolayer films. 

Fig. 37 Surface potential versus molecular area plot for monolayers of meso- and (+ )-azobis[6-(6-cyanododecanoic acid)] spread statically on a pH 3 subphase.

Static 2H NMR spectra suffer from low sensitivity, as resonances are spread continuously over the 200 kHz range. In samples with multiple sites, they also lack resolution. However, both shortcomings can be remedied by using MAS. As was shown in Sect. 2.3.3, in a rigid sample MAS averages out the inhomogeneous first-order quadrupolar broadening in the same way as it eliminates the CSA in... 

Figure 33 is particularly instructive because it shows the drastically different responses to compression of the racemic monolayer and the enantiomeric ones. Consistent with static surface tension results (Fig. 32), the enantiomeric amide does not even spread as a mono-layer on 3Af H2SO4. On all three acid subphases, the racemic material... 

Equilibrium spreading pressures, like static surface tension measurements, provide a means to determine surface energies under equilibrium conditions. On lOA H2SO4, racemic crystals (Fig. 10) spread within 5 min to an equilibrium pressure of 8.6 dynes/cm, whereas about 8 hr was required by either (i )-(+)- or (5)-(-)- crystals to spread to a final pressure of 5.5 dynes/cm. 

Pollutants emitted by various sources entered an air parcel moving with the wind in the model proposed by Eschenroeder and Martinez. Finite-difference solutions to the species-mass-balance equations described the pollutant chemical kinetics and the upward spread through a series of vertical cells. The initial chemical mechanism consisted of 7 species participating in 13 reactions based on sm< -chamber observations. Atmospheric dispersion data from the literature were introduced to provide vertical-diffusion coefficients. Initial validity tests were conducted for a static air mass over central Los Angeles on October 23, 1968, and during an episode late in 1%8 while a special mobile laboratory was set up by Scott Research Laboratories. Curves were plotted to illustrate sensitivity to rate and emission values, and the feasibility of this prediction technique was demonstrated. Some problems of the future were ultimately identified by this work, and the method developed has been applied to several environmental impact studies (see, for example, Wayne et al. ). 

Previously, hver shces were incubated in static organ cultures [1]. Hart et cd. [49] cultured rat hver slices for 24 h spread out on wet filter paper, floating on top of the incubation medium. Several slice-containing vessels were placed in a box with saturated 95% O2 and 5% CO2 at 37°C. However, the shces employed were rather thick (approximately 0.3 mm) and only the upper cell layers (0.2 mm) in the slice contained viable ceUs. Together with the introduction of the Krumdieck sheer [5,46], a new incubation technique for shces, the dynamic organ culture system (DOC), was introduced [35]. The main characteristic of this system is the intermittent exposure of the shce to incubation medium and the gas phase. The DOC is in fact a modified version of the Trowell incubation system [1]. 

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