Particle velocity measurements in induction plasma spraying

Laser Dopple anemometry (LDA) measurements of the particle velocity are carried out during an induction plasma spraying operation. The velocity of nickel alloy particles, or molten droplets, at the exit of an induction plasma torch prior to impact on the substrate is shown to vary with the plasma and powder injection conditions. Plasma spraying under soft vacuum (150–450 Torr) gives rise to substantially higher particle velocities (40–60 m/sec) compared to those attained at atmospheric pressure (10–20 m/sec).     

Solventless injecction for packed column supercritical fluid chromatography

The adverse effects of injection solvent strength on microbore packed column SFC band broadening are demonstrated and a solventless injection system that eliminates these effects is introduced. The injection system removes solvent in a GC-like manner using a retention gap and an on-column capillary GC syringe. The analyte is delivered to the analytical column in a solvent-free plug of supercritical fluid mobile phase.     

Theoretical study on the structure and property relationship of the cationic conjugated polyelectrolytes

A theoretical study using density functional theory was performed to understand the structure/property relationship of the cationic conjugated polyelectrolytes, poly[9,9-bis-(6′-N,N,N-trimethylammonium) hexyl] fluorene-alt-4,7-(2,1,3-benzothiadiazole)] (PFBT-X, where X = Br). The torsion angle between the fluorene and benzothiadiazole units in the PFBT monomer was found to substantially affect the structural and electronic properties of the cationic PFBT monomer. The changes of geometrical parameter, HOMO and LUMO energy levels, and band gap, as well as the absorption maximum are discussed in terms of the torsion in the PFBT monomer structure. For comparison, its neutral analogue, the monomer of poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) (F8BT) was also studied. The length of conjugation backbone was also examined.     

Remote substituent effect favoring the formation of syn-adducts in the chelation controlled radical reactions of γ-benzyloxy-α-methylenecarboxylic acid esters

The chelation controlled radical reactions of ethyl γ-benzyloxy-α-methylenecarboxylates bearing a bulky γ-substituent, such as CHMe₂, CHPh₂, c-C₆H₁₁ and CH(Ph)OTBDMS, with alkyl iodides gave the syn-adducts with high diastereoselectivities. However, the diastereoselectivity for the substrates bearing a γ-substituent CH(i-Pr)OTBDMS depended critically on the configuration of the substituent; the substrate bearing the OTBDMS group anti to the γ-benzyloxy group showed poor diastereoselectivity, but its diastereomer gave syn-adduct exclusively. The high syn-selectivitiy is referred to the H-atom transfer to the outside face of radical center in the sharply folded seven-membered chelate intermediate bearing the ethoxy group with Z-geometry. The corner flapping of the radical center atom of the global minimum energy conformer generates a local minimum conformer and the H-atom transfer to the outside face of the radical center of the newly formed structure gives the anti-adduct. The poor diastereoselectivity is due to the very small energy difference between the two conformers and consequently both the syn- and anti-adducts are yielded in nearly equal amounts.     

SPECIFIC PROTEIN OCCURRENCE RELATED WITH PHOTOPERIODIC FLOWER INDUCTION IN THE COTYLEDONS OF Pharbitis nil CV. VIOLET

In our experiment, three groups of seedlings of SDP Pharbitis nil cv. violet were sepa-rately treated with three different photoperiods (1,16 h dark period--SD; 2, continuous illumi-nation--CL; 3, 16 h dark treatment with 10 min white light in the middle of the dark period--NB). By analysing proteins in the cotyledons from three groups with 2-D PAGE, we found nodifference in protein pattern between the three groups at 0 or 8 h after photoperiodic treatments.At 24 h after the treatments, a specific protein(MW:19 kD; pI: 4.5)appeared only in the cotyledonsof the seedlings which endured SD. This protein disappeared at 72 h after SD. ActinomycinD could inhibit flowering and the specific protein occurrence when applied to cotyledonsprior to SD, but it had no inhibition effect on flowering as well as the specific proteinoccurrence when applied to cotyledons after SD. Chloroamphenicol, a protein synthesisinhibitor, inhibited flowering when applied to cotyledons prior to or immediately after SD,but it did not i     

Study of Structures and Electronic Properties of Pdn–1Pb and Pdn （n≤8） Clusters

Geometric and electronic properties of Pdn–1Pb and Pdn (n≤8) clusters have been studied by using density functional theory with effective core potentials, focusing on the differences between mono- and bimetallic clusters. The average bond length of Pdn–1Pb (n≤8) bimetallic clusters is longer than that of pure palladium clusters except for n = 2 and 3. The most stable structure of Pdn–1Pb (n≤7) is the singlet where there is at least a Pd or Pb atom on its excited state. The energy gaps of Pd–Pb binary clusters are narrower than those of Pdn clusters, and then the chemical activity is strengthened when Pdn clusters are doped with Pb.     

内含式化合物X@Al12P12的结构与稳定性研究

采用B3LYP/6-31G*方法, 对内含式化合物X@Al₁₂P₁₂ (X＝Li^0/＋, Na^0/＋, K^0/＋, Be^0/2＋, Mg^0/2＋, Ca^0/2＋, H和He)的不同对称性构型进行计算, 讨论其最稳定构型的几何参数、布居分析、偶极矩、电离势、包含能、频率、HOMO-LUMO能隙和自旋密度．发现X@Al₁₂P₁₂化合物中, 客体X＝Na^0/＋, K^0/＋, Mg和He几乎处在笼的中心, Be和Ca^0/2＋处在中心附近0.033 nm的半径内, Li^0/＋, Be^2＋, Mg^2＋和H很大程度上偏离笼的中心位置. 大部分金属内含式化合物的C₃对称性构型稳定．Li^0/＋, Be^0/2＋, Mg^2＋, Ca^2＋和H与其它离子相比更易嵌入笼内形成稳定的内含式化合物.     

Estimates of logarithmic Sobolev constat for finite-volume continuous spin systems

LetM be a compact, connected Riemannian manifold (with or without boundary); we study the logarithmic Sobolev constant for stochastic Ising models on . Let {} be a sequence of cubes inZ ^d ; we show that the logarithmic Sobolev constant for the finite systems onM ^A shrinks at most exponentially fast in ||^(d-1)/d (d2), which is sharp in order for the classical Ising models withM=[–1, 1]. Moreover, a geometrical lemma proved by L. E. Thomas is also improved.     

On the two-dimensional stochastic Ising model in the phase coexistence region near the critical point

We consider the two-dimensional stochastic Ising model in finite square with free boundary conditions, at inverse temperature >₀ and zero external field. Using duality and recent results of Ioffe on the Wulff construction close to the critical temperature, we extend some of the results obtained by Martinelli in the low-temperature regime to any temperature below the critical one. In particular we show that the gap in the spectrum of the generator of the dynamics goes to zero in the thermodynamic limit as an exponential of the side length of , with a rate constant determined by the surface tension along one of the coordinate axes. We also extend to the same range of temperatures the result due to Shlosman on the equilibrium large deviations of the magnetization with free boundary conditions.