For the sake of computation cost, prestack depth migration by nonstationary phase shift is implemented using a piecewise constant approximation, the migrated Marmousi result shows that the nonstationary phase shift migration for heterogenous media is feasible.

A generalized high order screen extrapolator of double square root (DSR) equation is derived from the non-stationary phase shift formula of wavefield continuation, thus a new prestack depth migration method in the cmp-offset domain is proposed.

Based on non station ary phase shift formula for wave field extrapolation and through introducing re ference velocity,the paper deduced a new high order screen approximate formula conducted wave field continuation in CMP offset domain,using Taylor's series ex tension for two square roots in DSR and suitable mathematical process.

Conventional phase shift operator requires that the velocity be laterally constant, while nonstaionary phase shift operators such as PSPI, NSPS SNPS overcome the shortcoming. The symmetric SNPS operator, a combination of NSPS and PSPI, has better accuracy and stability than NSPS or PSPI.

Nonstationary phase flow and rectification acceleration in industrial plant

Nonstationary phase processes are defined and a surrogate distribution approximation (SDA) method for analyzing transient and nonstationary queueing systems with nonstationary phase arrival processes is presented.

Applying the split-step technique to the solutions of nonstationary phase-shift leads to the three split-step Fourier schemes.

It speeds up the original nonstationary phase-shift but retains accuracy.

The windowed nonstationary phase-shift method presented in this paper can handle wavefield extrapolation in strong laterally variant velocity media.

A kinetic approach to phase transition of liquid crystalline polymers was deduced. On the basis of physical chemistry, a kinetic equation concerned the phase transition of liquid crystalline polymers was established, and a new kinetic parameter of transition order was proposed. Hence the quantitative determination of the order of phase transition was obtained. In addition, the kinetic approach was applied to a new series of polymer systems, and the kinetic order of phase transition of the polymers was decided.It...

A kinetic approach to phase transition of liquid crystalline polymers was deduced. On the basis of physical chemistry, a kinetic equation concerned the phase transition of liquid crystalline polymers was established, and a new kinetic parameter of transition order was proposed. Hence the quantitative determination of the order of phase transition was obtained. In addition, the kinetic approach was applied to a new series of polymer systems, and the kinetic order of phase transition of the polymers was decided.It is concluded that the clearing transition is of first order, and the smectic-smectic transition second order, while the order of melting and solid-solid transition varies with the polymer structure.

In this paper,4 methacryloyl 2,2,6,6 tetramethyl piperidine(MTMP)was synthesized.By using Photo DSC technique,the reactivity and the reaction kinetics of photo induced polymerization of MTMP were systematically studied.Results obtained have showed that the photo induced polymerization of MTMP is significantly influenced by such reaction conditions as the type and concentration of photoinitiator,polymerization temperature,ambient environment as well as irradiancy,and that the rate of photopolymerization...

In this paper,4 methacryloyl 2,2,6,6 tetramethyl piperidine(MTMP)was synthesized.By using Photo DSC technique,the reactivity and the reaction kinetics of photo induced polymerization of MTMP were systematically studied.Results obtained have showed that the photo induced polymerization of MTMP is significantly influenced by such reaction conditions as the type and concentration of photoinitiator,polymerization temperature,ambient environment as well as irradiancy,and that the rate of photopolymerization of MTMP is directly proportional to the square root of photoinitiator concentration([PI] 0 5 ) and incident light intensity(I 0 0 5 ),which is in accordance with the theoretical expectation.The kinetic parameters( k p and k t )of the bulk photopolymerization of MTMP have been determined by Photo DSC.The rate of propagation constant k p and the rate of termination constant k t have been found to be increased with the increase of MTMP conversion,but is much larger than k p .

4-acrylamido-2,2,6,6-tetramethyl-piperidine(AATP),a water soluble r-HALS,is synthesized and the structure and composition of AATP is characterized by FT-IR,~1H-NMR and elemental analysis.The reaction kinetics of photoinduced bulk polymerization of AATP in melting state is studied by using photo-DSC (DPC) technique.The results show that the conversion and the rate of AATP photopolymerization are obviously affected by the reaction condition such as temperature,incident light intensity and concentration of photoinitiator...

4-acrylamido-2,2,6,6-tetramethyl-piperidine(AATP),a water soluble r-HALS,is synthesized and the structure and composition of AATP is characterized by FT-IR,~1H-NMR and elemental analysis.The reaction kinetics of photoinduced bulk polymerization of AATP in melting state is studied by using photo-DSC (DPC) technique.The results show that the conversion and the rate of AATP photopolymerization are obviously affected by the reaction condition such as temperature,incident light intensity and concentration of photoinitiator etc.Darocur 1173 is the available initiator and the optimum mass fraction of Darocur 1173 is 0.5—1.0 %.The rate of AATP photopolymerization is proportional to the square root of photoinitiator concentration c~(0.5)_(PI) and incident light intensity I~(0.5)_0 respectively under given condition.The kinetic parameters of photoinduced bulk polymerization for AATP were measured at the steady and non-steady state.The rate constants for termination k_t is much larger than that for propagation k_p(k_p/k_t=3.43—33.57).k_t and k_t is increased with the conversion increasing in the reaction system.k_p and k_t is 2.22—7.96×10~2 and 0.08—2.67×10~4(L/mol·s) corresponding to a conversion from 4.00% to 15.68%,respectively.These values are within the range of corresponding parameters typical for a free radical polymerization.The induction period of the reaction system is decreased with the increment of photoinitiator concentration and incident light intensity respectively.Because of apparent activation energy of the reaction system is negative [E_p-E_t/2 is from -7.70 to -13.36 kJ/mol] and A_p/A_t~(0.5) is from 0.076 to 0.333(L/mol·s)~(0.5),the rate of AATP photopolymerization is decreased with increment of the temperature from 110 ℃ to 150 ℃ and the irradiating time of that is prolonged.