CHEMICAL STRUCTURE DEPENDENCE OF THE INTERNAL ENERGY CONTRIBUTION IN RUBBER ELASTICITY

Conformational elasticity theory recently developed has been used to explore the internal energy contribution to the elastic force f(e)/f as a function of strain for poly(cis-1,4-isoprene) and poly(trans-1,4-isoprene). Calculated f(e)/f values are in good agreement with those obtained experimentally. Results show that behavior of f(e)/f is mainly contributed by chemical structure, or intramolecular interaction, supporting the experimental observations, and that the internal energy contribution is strain dependent.

Two Typical Examples of Scaling Ionic Partition Scheme for Estimating Correlation Energy of A_2 Type Molecules

Based on the calculation results of pair correlation energy contributions of the various electron pairs in Na2 and H2NNH2 systems and the application of the scaling ionic partition scheme for symmetrical A2 type systems, the to-tal correlation energies of Na2 and H2NNH2 have been reproduced by using this simple scheme. The two results show that the absolute deviations are within an acceptable range of error, however, in this way, more than 90% of computational work can be saved. The most attractive result in present paper is that, in these two molecules the co-efficients c1 and c2 in the estimation equation can be obtained by the proportion of correlation energy of A- to that of A+ singlet system. Therefore, it is believed that the proposed ionic partition scheme for symmetrical A2 mole-cules would be very useful to estimate the correlation energies of large symmetrical molecules.

Effects of Additional Rifle-Carriage Training on Physiological Markers and Roller-Skiing Performance in Well-Trained Biathletes

Purpose The purpose was to investigate whether an increased amount of training while carrying the rifle affects skiing in well-trained biathletes at submaximal and maximal workloads during a pre-season period lasting a minimum of 12 weeks.Methods Seventeen well-trained biathletes(9 females,8 males)were assigned to an intervention(IG,n=10)or control(CG,n=7)group.Before(T1)and after(T2)the training intervention all participants performed,using treadmill roller-skiing,a submaximal test without the rifle on one day and two submaximal workloads and a maximal time trial(TT)with the rifle on a subsequent day.Between T1 and T2 all participants performed a minimum of 12 weeks of normal training,the only difference between groups being that IG performed more of their training sessions carrying the rifle.Results IG performed more training compared to CG(15.4±1.1 vs.11.2±2.6 h/week,P<0.05),including a higher amount of training with the rifle(3.1±0.6 vs.1.1±0.3 h/week,P<0.001).Speed at 4 mmol/L of blood lactate increased significantly for CG from T1 to T2(P=0.028),while only tended to increase for IG(P=0.058).Performance during the TT,VO2max and the aerobic metabolic rate increased significantly from T1 to T2,although the differences disappeared when including the speed at baseline as a covariate.Conclusion According to the present results,increasing training while carrying the rifle by 2 h/week does not appear to improve skiing performance in well-trained biathletes.In addition,physiological markers at submaximal and maximal intensities while carrying the rifle were not affected after the training intervention.