Terminal Effect of Drop Coalescence on Single Drop Mass Transfer Measurements and Its Minimization

For the mass transfer to single drops during the stage of steady buoyancy-driven motion, experimental measurement is complicated with the terminal effect of additional mass transfer during drop formation and coalescence at the drop collector. Analysis reveals that consistent operating conditions and experimental procedure are of critical significance for minimizing the terminal effect of drop coalescence on the accuracy of mass transfer measurements. The novel design of a totally-closed extraction column is proposed for this purpose, which guarantees that the volumetric rate of drop phase injection is exactly equal to that of withdrawal of drops. Tests in two extraction systems demonstrate that the experimental repeatability is improved greatly and the terminal effect of mass transfer during drop coalescence is brought well under control.

Influence of structure parameters on terminal effect of small caliber PELE impacting metal target

By changing the length-diameter ratios and inner-to-outer diameter ratios, some numerical simulations were made on PELE normal penetrating metal target using AUTODYN-3D code. The influence rules of length-diameter ratio and inner-to-outer diameter ratio to the terminal effect of PELE are obtained. When the length-diameter ratio is in the range of 4-7, inner-to-outer diameter ratio is in the range of 0.54-0.72, the PELE can perform satisfactory double terminal effects embodied in armor-piercing and fragment killing. Based on simulation results, a test projectile is designed and an impact experiment of PELE is carried out, which demonstrate the efficiency of the simulation method.

A New and Effective Synthesis of Terminal Alkylselenylacetylenes

The terminal alkylselenylacetylenes (RSe-C = C-H) 3a-h were prepared by the reaction of ethynylmagnesium bromide at -20 degrees C in THF with alkylselenyl bromides derived from dialkyl diselenides and bromide.

Studies on the effect of opposite terminal groups in phenylpolyenic conjugative systems

Seven homologous series p-A=B-C_6H_4(CH=CH)_nX=Y (A=B: NO_2, X=Y: CHO, COMe, CN, NO_2; A=B: CN, X=Y: CHO, CN; A=B: H, X=Y: NO_2) were synthesized, the effect of opposite terminal groups in phenylpolyenic conjugative systems has been studied by means of UV, XPS, ^(13) C NMR and quantum chemical calculation. The results show that: 1. There exists the effect of opposite terminal groups exists in phenylpolyenic and other aromatic conjugative systems. 2. When A=B and X=Y are the same, the group (-X=Y) connected at polyenic chain is a terminal group, while the other is an opposite terminal group. When the two groups are different, the one with weaker conjugative power plays the role of the opposite terminal group. 3. The effect of opposite terminal groups increases successively in the order of CN, COMe, CHO, NO_2 and can be quantita- tively described with substitute equivalent △N_s. Theλ_(max) of compound containing an opposite terminal group can be calculated by the homologous equation 10^(-4) =a+b/(1/2)^(2/N＇^(-S)_a), most of the calculated values are in agreement with experiment results.

Time-varying latent model for longitudinal data with informative observation and terminal event times

Longitudinal data often occur in follow-up studies, and in many situations, there may exist informative observation times and a dependent terminal event such as death that stops the follow-up. We propose a semiparametric mixed effect model with time-varying latent effects in the analysis of longitudinal data with informative observation times and a dependent terminal event. Estimating equation approaches are developed for parameter estimation, and asymptotic properties of the resulting estimators are established. The finite sample behavior of the proposed estimators is evaluated through simulation studies, and an application to a bladder cancer study is provided.