Propeller wake flowfield analysis by means of LDV phase sampling techniques

 Two phase sampling techniques are developed for the analysis of the propellers wake by means of LDV. The first one (TTT) uses the detection of Doppler signal as trigger condition; each LDV sample, tagged with the blade angular position at the measurement time, is arranged inside angular slots. The other technique (ATT) follows an angular triggering method, with some enhancements to reduce measurement time. The implemented techniques are complementary from the accuracy and efficiency point of view. The TTT enables to quickly analyze the propellers wake, in view of the minimization of data acquisition time, particularly in poor flow seeding conditions. The ATT is instead suitable for accurate investigations of space-limited and highly turbulent flow regions. Received: 29 July 1998/Accepted: 18 February 1999     

An expansion for the number of partitions of an integer

The Ramanujan Journal - We consider p(n) the number of partitions of a natural number n, starting from an expression derived by Báez-Duarte in (Adv Math 125(1):114–120, 1997) by relating...     

The influence of captodative effect on the dienophilicity of olefins. The easy diels-alder reaction of α-methylthioacrylonitrile with cyclohexadiene

We show that the cycloaddition of α-methylthioacrylonitrile to cyclohexadiene is faster than that of acrylonitrile. This indicates that the captodative substitution exerts an accelerating effect on the Diels-Alder reaction despite the larger steric bulk of the methylthio group compared to hydrogen.     

Targeted destruction of murine macrophage cells with bioconjugated gold nanorods

Gold nanorods manifest a readily tunable longitudinal plasmon resonance with light and consequently have potential for use in photothermal therapeutics. Recent work by others has shown how gold nanoshells and rods can be used to target cancer cells, which can then be destroyed using relatively high power laser radiation (∼1×10⁵ to 1×10¹⁰ W/m²). Here we extend this concept to demonstrate how gold nanorods can be modified to bind to target macrophage cells, and show that high intensity laser radiation is not necessary, with even 5×10² W/m² being sufficient, provided that a total fluence of ∼30 J/cm² is delivered. We used the murine cell line RAW 264.7 and the monoclonal antibody CD11b, raised against murine macrophages, as our model system and a 5 mW solid state diode laser as our energy source. Exposure of the cells labeled with gold nanorods to a laser fluence of 30 J/cm² resulted in 81% cell death compared to only 0.9% in the control, non-labeled cells.     

α—NiSO4.6H2O晶体磁园二色谱和吸收谱的研究

用磁园二色谱和光吸收谱对α－ＮｉＳＯ４．６Ｈ２Ｏ晶体进行了测量和研究，实验结果表明在λ＝１８５～３３００ｎｍ范围内存在一系列吸收结构，其中三个主要主要吸收带结构分别对应于晶体中Ｎｉ离子基态到有关激发态的ｄ－ｄ跃迁，对它们进行了初步指认，实验中观测到红带的λ＝６５４ｎｍ和λ＝７１３ｎｍ两结构间存在一系列弱的结构峰，它们主要与自旋轨道耦合相互作用结果有关，在磁园二色谱中还观测到λ＝５８５ｎｍ的强吸收峰     

Optical properties of Ti1−x Hf x Se2 layered compounds from 1 to 9 eV

Summary The main structures of interband spectra of Ti_1−x Hf _x Se₂ crystals (0≤x≤0.3 andx=1) have been investigated by means of thermoreflectance from 1 to 9 eV. New indications about the correspondence of the interband spectra of TiSe₂ and HfSe₂ are given. Detailed data at intermediate stoichiometries, which give also evidence of possible bowing effects, are reported and discussed. No relevant effect of the 200 K phase transition in TiSe₂ is observable above 2 eV.

---

Riassunto Sono state studiate, mediante la tecnica della termoriflettanza, le principali strutture dello spettro interbanda dei cristalli Ti_1−x Hf _x Se₂ (0≤x≤0.3 ex=1), fra 1 e 9 eV. Si sono così ottenute nuove indicazioni circa la corrispondenza fra gli spettri interbanda del TiSe₂ e dell'HfSe₂. Si riportano in dettaglio e discutono i dati di termoriflettanza a valori intermedi dix con evidenza di possibili effetti di ?bowing?. Non sono stati osservati apprezzabili effetti della transizione di fase a 200 K ad energie superiori a 2 eV.

---

Резюме Исследуются главные особенности междузонных спектров кристаллов Ti_1−xHf _x Se₂ (0≤x≤0.3 иx=1) с помощью техники термоотражения в области от 1 до 9 эВ. Приводятся новые данные о соответствии между междузонными спектрами TiSe₂ и HfSe₂. Подробно обсуждаются данные при промежуточных значенияхx. Не наблюдаются заметные эффекты фазового перехода при 200 К в TiSe₂ при энергиях выше 2 эВ.

     

Velocity of the fourth sound in liquid helium II via extended thermodynamics

This work continues a study begun in previous works, where, using Extended Thermodynamics, a monofluid model of liquid helium II is formulated. The wave propagation in bulk liquid helium II is studied in the hypothesis that the thermal dilatation is not zero. The propagation of fourth sound, studied previously neglecting both the thermal dilatation and finite volume of the powder, is studied without these simplified hypotheses: a scattering correction n is introduced to take into account the porosity. The model is more general than the standard two-fluid model because it allows that a small amount of entropy is associated with helium when it flows through a very thin capillary or a porous medium. A comparison with experimental data is performed. From experimental values for velocities and attenuations of the two sounds in bulk liquid helium, the model provides the velocity of fourth sound in a porous medium. These values are determined at various temperatures and pressures and compared with fourth sound measurements in a packed powder.     

Douglas–Rachford splitting and ADMM for nonconvex optimization: accelerated and Newton-type linesearch algorithms

Computational Optimization and Applications - Although the performance of popular optimization algorithms such as the Douglas–Rachford splitting (DRS) and the ADMM is satisfactory in convex...     

Influence of ultrasound on the kinetic parameters of electrochemical redox reactions

The aim of this work is to determine the Tafel parameters with and without ultrasound. The total overvoltage has been corrected for diffusion by using rotating disk technique and potentiostatic extrapolation to infinite rotating speed. Three well known redox systems have been selected regardless to their different electrochemical behaviour: the quinone-hydroquinone, the Fe(II)Fe(III) chlorides and Fe(II)-Fe(III) cyanide systems. This work shows that the reversibility is higher with ultrasound only in the case of the quinone-hydroquinone system.     

Simultaneous determination of tetrathiomolybdates and molybdates in spiked blood plasma by differential pulse voltammetry and their speciation

A selective, sensitive and reliable voltam- metric method for the simultaneous determination of MoS^2-₄ and MoO^2-₄ has been developed. The reduction of HgMoS₄ at –0.43 V and the reduction of Mo as complex of MoO₂-oxine₂ at –0.63 V in acetate buffer at pH 4.9 are utilized for the simultaneous determination by differential pulse cathodic stripping voltametry (DPCSV). Cadmium and lead form complexes with MoS^2-₄, but do not interfere with the determination. The limit of detection is 0.59 g/l Mo for MoS^2-₄ and 1.8 g/l Mo for MoO^2-₄. The R.S.D at a concentration level of 20 g/l is 4.7% for MoO^2-₄ and 3.6% for MoS^2-₄. The method is applied to spiked blood plasma samples for the determination of free tetrathiomolybdates and molybdates. Additionally, labile tetrathiomolybdates and molybdates can be determined in spiked blood plasma after treatment of the sample with 0.15 mol/lKCN and ultrafiltration.