The electron capture of H+ ions in solid foils

The negative ion yields φ (H-)and the neutral atom yields φ (H) of 0.6, 0.9, 1.2, 1.6 and1.8 MeV H+ projectiles traversing various carbon foils have been measured. The experimental re-sults showed that neither φ (H-) nor φ (H) varies with the dwell time td at the same energy. φ (H) islarger than φ (H-) by about 3-4 orders of magnitude. The charge exchanging between H+ ionsand carbon foils was analyzed. It can be seen that the charge exchange is the most basic proc-ess.The experience formula of σc/σ/has been gotten.     

Correction of the Gurson yield criterion

The correction in the derivation of the Gurson yield criterion is reported. A prerequisite kinematical condition ignored in Gurson's paper is imposed, and a parameter (C₁), which was unreasonably set to zero, is restored.     

二氧四胺大环配合物光谱特性与其催化活性关系的研究

测量并研究了二氧四胺大环配体 1,4,7,10 四氮杂环十三烷 11,13 二酮及其Cu(Ⅱ )、Co(Ⅱ )、Ni(Ⅱ )配合物在不同 pH值下的常规荧光谱和激光诱导荧光谱 ,发现配合物的荧光量子产率满足 ΦCuL5<ΦCoL5<ΦNiL5的关系 ,并对其作了解释。与此同时 ,分析了其作为模拟超氧歧化酶的催化活性和荧光光谱特性的关系 ,由三种配合物的荧光量子产率 ,推测出其催化活性的关系可能是CuL5>CoL5>NiL5。     

What is the maximum yield in the solid state cinnamic acid dimerisation? A combinatorial mathematical approach

Recurrence relations have been employed to obtain the maximum possible theoretical conversion in a topochemically controlled organic solid state reaction. Experimental deviations from this analytical value of ≈82% reflect the importance of defects, molecular relaxation and surface phenomena in real crystals.     

A study on effect of sonochemistry in a reverberation field

In this paper,an ultrasound with frequency of 815 kHz was used to re-search the sonochemical yield in a small-size reverberation field by the methodof fluorescent spectrum analysis.There are two characteristics on the effect ofsonochemistry in the reverberation field:First,the cavitation threshold wasabout 0.3W/cm~2(it was 0.7W/cm~2 in travelling field);Second,when thesound intensity was larger than the threshold,the sonochemical yield increasedas the intensity increased and increased rapidly after the intensity was at1.69-2.13W/cm~2,so that there was a upturned point in the curve of the result(which would tend to saturation in the travelling field).The theoretical analysisshows that the reason of the threshold decrease is that the sound energy densitybecomes high in the reverberation field,and the upturned point results from thedisturbance of the radiation pressure on the liquid surface.Therefore,by exper-iment and theory this paper shows that a reverberation field has to be built forthe higher sonoche     

In vitro sonodynamic cytotoxicity in regulated cavitation conditions

Sonodynamic toxicity has always been linked to the cavitation phenomenon. In this work, sonodynamic effect with Photofrin^® was evaluated with a new ultrasound device: a regulated cavitation generator. In this way, acoustic intensity was substituted with cavitation level as ultrasound parameter. Photofrin^® potentiated significantly the cavitation cytotoxicity even for low setpoints where no inertial cavitation appeared. Therefore sonodynamic mechanism was principally mechanical, facilitated by the Photofrin^® insertion in cellular cytoplasmic membranes. This assertion was also supported by the fact that sonodynamic cytotoxicity was independent from the Photofrin^® presence or absence in the extracellular medium. Reproducible sonodynamic efficiency was perfectly obtained with this new regulated cavitation generator.     

Sonochemical method for producing titanium metal powder

We demonstrate a sonochemical method for producing titanium metal powder. The method uses low intensity ultrasound in a hydrocarbon solvent at near-ambient temperatures to first create a colloidal suspension of liquid sodium–potassium alloy in the solvent and then to reduce liquid titanium tetrachloride to titanium metal under cavitation conditions. XRD data collected for the reaction products after the solvent removal show only NaCl and KCl, with no diffraction peaks attributable to titanium metal or other titanium compounds, indicating either the formation of amorphous metal or extremely small crystallite size. TEM micrographs show that hollow spheres formed of halide salts and titanium metal, with diameters with diameters ranging from 100 to 500 nm and a shell thickness of 20 to 40 nm form during the synthesis, suggesting that the sonochemical reaction occurs inside the liquid shell surrounding the cavitation bubbles. Metal particle sizes are estimated to be significantly smaller than 40 nm from TEM data. XRD data of the powder after annealing and prior to removal of the alkali chloride salts provides direct evidence that titanium metal was formed during the sonochemical synthesis.     

Numerical modelling of foam Couette flows

A numerical computation based on a tensorial visco-elasto-plastic model based on continuous mechanics is compared to experimental measurements on liquid foams for a bidimensional Couette flow between two glass plates, both in stationary and transient cases. The main features of the model are elasticity up to a plastic yield stress, and viscoelasticity above it. The effect of the friction of the plates is taken into account. The numerical modelling is based on a small set of standard material parameters that are fully characterised. Shear localisation as well as acute transient observations are reproduced and agree with experimental measurements. The plasticity appears to be the fundamental mechanism of the localisation of the flow. Finally, the present approach could be extended from liquid foams to similar materials such as emulsions, colloids or wet granular materials, that exhibit localisation.     

石油期货价格距到期日效应波动实证研究

世界石油期货价格是否存在价格的波动性随到期日的临近而上升的趋势,对于投机商和市场监管都至关重要.研究根据中外石油期货合约的收盘价格得到较为平稳的日收益率,以37个合约的收益率为样本,分别建立时间序列ARM A主模型,并进一步建立带"到期时间"哑变量的GARCH模型.实证分析了世界石油期货收益率的到期日效应.在分析产生到期日效应原因的时,建立了带"成交量"与"国际价格"变量的GARCH模型,对成交量与国际石油期货价格对中国期货价格到期日的影响进行研究.     

Experimental research into the cavitation noise spectrum in water solutions of high molecular weight polymers

The paper presents cavitation noise spectrum measurements results for water and a water solution of polyacryloamide with the 1.5 × 10⁷ g mol⁻¹ particle mass. Cavitation noise spectrum characteristics were shown for different ultrasound intensity, with different sonification times (at a constant ultrasound intensity) as well as characteristics which enable comparing particular sonification parameters.