Influence Of Volume Change Research Articles

Study on the influence of volume change of tumor bed on radiotherapy dose volume distribution after breast conserving surgery for early breast cancer

Objective To study the influence of volume change of tumor bed on radiotherapy dose volume distribution after breast conserving surgery for early breast cancer. Methods 13 early breast cancer patients received breast-conserving surgery were selected. For all 3 CT scanning in patients with tumors, row delineation of tumor and normal tissue target positioning, the tumor bed after volume as well as the planned radiation dose volume were compared in three times of scans. Results 13 cases of three CT scans of patients with tumor bed volume point to (32.85±9.30)cm3, (24.50±4.71)cm3, (16.48±4.46)cm3, there were statistically significant differences before and after(t=2.888, 5.723, 4.458, all P<0.05); 3 planned radiation dose in patients with volume was stepped down, and the differences were statistically significant (F=20.28, 96.32, 14.21, 16.75, 26.29, all P<0.001). Conclusion Earlier the tumor bed following breast surgery volume decreased rapidly, tumor volume change will affect the target area of the bed covers and the exposure of normal tissue dose-volume. Key words: Breast neoplasms; Radiotherapy

Pressure effect on the resistivity in GMR La0.60Y0.07Ca0.33MnO3 compound (abstract)

The substitution of La+3 by smaller Y+3 ions in mixed valence Mn+3–Mn+4 perovskites La0.67−xYxCa0.33MnO3 gives rise to a decrease of the order temperature (Tc=160±5 K for x=0.07 and Tc=240 K for x=0). One of the most relevant features found in this compound was the extremely large magnetoresistance observed in bulk polycrystals (≊−10 000%) near Tc. This huge effect was associated with the reduction of the lattice parameter. In order to have an insight into the influence of volume change on transport properties in this compound, we have performed measurement of the thermal dependence of the resistivity under hydrostatic pressure up to 8 kbar. At ambient pressure a peaklike anomaly in the resistivity is observed at Tc. Under the former assumptions, one would expect an increase of the resistivity value at the maximum as well as a decrease of Tc. However, we have found a shift toward higher temperatures and a drastic decreasing of the maximum in the resistivity for increasing pressures. At a pressure of 7.5 kbar the anomaly in the resistivity almost disappears and consequently the GMR effect. As a consequence, the effect of pressure seems to be identical to the effect of the applied magnetic field. Ibarra et al. recently observed a large spontaneous magnetovolume effect at Tc with an extra contribution to the lattice thermal expansion. This extra contribution was found to be suppressed by an applied magnetic field. From these preliminary results it seems that the interplay between magnetostrictive deformations and the shrinkage of the lattice by external pressure could be in the origin of the observed behavior.

Analysis of volume change effects in a fluidized bed catalytic reactor

AbstractA mathematical model based on the concept of an improved bubble assemblage model is developed for calculating the conversion of a reaction system involving a volume change in fluidized beds. The influence of volume change on the hydrodynamic behavior of gas in the bed, such as bubble size variation, superficial gas velocity change, and volume fraction occupied by each phase, is also investigated. It is found that increasing stoichiometric coefficient values results in larger bubble size, higher superficial gas velocities, higher crossflow rate between emulsion phase and bubble phase, and greater volume fraction of bubble phase, but smaller volume fraction occupied by the emulsion phase as well as lower conversions.

On the Dynamics of an Isothermal Radial‐Flow Plasma Etcher

Analytical expressions have been derived to describe the dynamics of one‐dimensional and two‐dimensional (with plug‐type flow) (PF2D) representations of an isothermal radial flow reactor etching silicon in a nitrogen trifluoride plasma. These predictions are compared with the numerical solution of a more realistic two‐dimensional model, i.e., one that features laminar flow (LF2D). Further, the one‐dimensional model has been compared at steady state with the LF2D model over a range of parameters in an effort to determine the range of validity of the one‐dimensional model. The influence of volume change has been shown to be significant for the steady state as well as the transient behavior of the system.

LXXV. The influence of volume change on the fluidity of mixtures of miscible liquids

LXXV. <i>The influence of volume change on the fluidity of mixtures of miscible liquids</i>