Electrochemical study and electrodeposition of copper in the hydrophobic tri-n-octylmethylammonium chloride ionic liquid media

The electrodeposition of metallic Copper in binary mixture ionic liquid/organic solvent (tri-n-octylmethylammonium chloride (TOMAC))/chloroform (CHCl₃) was investigated. The electrochemical behavior of Cu(II) in TOMAC/CHCl₃ at glassy carbon working electrode at room temperature was studied by cyclic voltammetry and spectroscopy impedance. The results from the cyclic voltammetry showed that the electrodeposition of metallic Cu in the binary mixture ionic liquid/organic solvent was an irreversible process and was controlled by the diffusion of Cu(II) on a glassy carbon working electrode. The average value of αn_α was found to be 0.23 at 25 °C and the diffusion coefficient (D₀) of Cu(II) was calculated to be 7.12 10^− 9 cm²/s at room temperature. The performance of TOMAC ionic liquid such as internal resistance has been investigated with electrochemical impedance spectroscopy (EIS). The scanning electron microscopy (SEM) micrographs was used to observe that the copper plating was moderately dense and contains fine crystallites with average sizes of about 1 μm at room temperature. Energy dispersive X-ray analysis (EDAX) profile showed that the obtained film was copper.     

N2+分子离子A2∏u-X2∑+g 系(2,0)带光外差速度调制光谱

采用光外差速度调制光谱技术研究了N2+分子离子A2∏u-X2∑+g 系(2,0)带转动光谱．由于所用技术的高灵敏度特性，精确地确定了该带310条谱线的频率，其中，那些重叠谱线的频率也通过解谱精确地确定了．利用标准Hamilton量，采用非线性最小二乘方法对该带进行了分析，获得了最精确的分子常数．     

可见区分光光度法测量水体色度

针对目前水质色度测量方法的局限性,采用分光光度法测量相关色度学参数,通过色度学参数与国家标准方法的色度值建立数值关系,从而测定水体的色度值.该方法不仅保证测量结果与现行国家标准测量结果一致,而且客观性强,稳定可靠,灵敏度更高,也更准确.克服了目视比色法需要水体与标准溶液色调一致的局限性,可以推广到其他色调的废水色度测量...     

强化对流传热场协同唯象机制及其控制

根据对流传热强度与流体中存在的各种内场及其外场的关系,从唯象上阐明了降低温度边界层厚度、增加流体扰动和增加近壁面速度梯度的强化对流传热方法的物理机制,其本质是控制流体中内场及其外场之间的相互协同。给出了当流体中存在内场和外场时强化对流传热场协同控制方法,以此可指导发展强化对流传热单元的新方法。     

Exact solutions of the generalized Lane–Emden equations of the first and second kind

In this paper we discuss the integrability of the generalized Lane–Emden equations of the first and second kinds. We carry out their Noether symmetry classification. Various cases for the arbitrary functions in the equations are obtained for which the equations have Noether point symmetries. First integrals of such cases are obtained and also reduction to quadrature of the corresponding Lane–Emden equations are presented. New cases are found.     

A moving zone of quiet for narrowband noise in a one-dimensional duct using virtual sensing

A frequent problem in active noise control is that the zone of quiet created at the error sensor tends to be very small. This means that the error sensor generally needs to be located close to an observer's ear, which might not always be a convenient or feasible solution. Virtual sensing is a method that can move the zone of quiet away from the error sensor to a desired location that is spatially fixed. This method has been investigated previously, and has shown potential to improve the performance of an active noise control system. However, it is very likely that the desired location of the zone of quiet is not spatially fixed. An active noise control system incorporating a virtual sensing method thus has to be able to create a moving zone of quiet that tracks the observer's ears. This paper presents a method for creating a moving zone of quiet based on the LMS virtual microphone technique. To illustrate the proposed method, it is implemented in an acoustic duct and narrowband control results are presented. These results show that a moving zone of quiet was effectively created inside the duct for narrowband noise.     

Observation of B(s)0-->K+ K- and measurements of branching fractions of charmless two-body decays of B0 and B(s)0 mesons in pp collisions at square root of s = 1.96 TeV

We search for decays of the type B(s)0-->h+ h'- (where h,h' = K or pi) in 180 pb(-1) of pp collisions collected at the Tevatron by the upgraded Collider Detector at Fermilab. We report the first observation of the new mode B(s)0-->K+ K- with a yield of 236+/-32 events, corresponding to (fs/fd) x B(B(s)0-->K+ K-)/B(B0-->K+ pi-) = 0.46+/-0.08stat+/-0.07syst, where fs/fd is the ratio of production fractions of B(s)0 and B0. We find results in agreement with world averages for the B0 modes, and set the following new limits at 90% C.L.: B(B(s)0-->K- pi+) < 5.6 x 10(-6) and B(B(s)0-->pi+ pi-) < 1.7 x 10(-6).     

The effect of increasing the excitation level of the sodium atom on the structure of the NaArn polyatomic exciplexes

In this work, the geometrical structures, the formation energies, and electronic states of the Na(ms)Ar_n polyatomic exciplexes with m = 3-6 and n = 2-5 are studied by using a quantum-classical method. The interaction potential between an electronically excited sodium atom and argon atoms are calculated by using a one-electron model involving electron-Ar and electron-Na⁺ pseudopotentials, in which the Hamiltonian is diagonalized at every optimization step in the Basin Hopping algorithm. The relationship between the position of the electronically excited levels and the cluster geometry is investigated as a function of the excitation level and of the spatial extension of the excited electron orbital. We show that the equilibrium structures of the ground state Na(3s)Ar_n and those of the electronically excited states Na(4s)Ar_n, Na(5s)Ar_n, and Na(6s)Ar_n are significantly different. As a result of the detailed examination of the relationships between the geometrical structure and density distribution of the Na valence electron of the Na^∗Ar_n with n = 2-5 polyatomic exciplexes, we can see that for the Na(4s)Ar_n polyatomic exciplexes, the two extreme geometries, neutral Na(3s)Ar_n and ionic Na⁺Ar_n compete. It appears that none of them is the actual one. For Na(5s)Ar_n and Na(6s)Ar_n the valence electron is very weakly bound to the ionic core and described by a more diffused orbital so that the geometry and the formation energies of this excited state called Rydberg states converge towards those of the ionic cores.     

Experimental and numerical study of the effect of conjugate heat transfer on film cooling

Combined convection heat transfer and thermal conduction for film cooling of a flat plate with 45° ribs on one wall was investigated experimentally and numerically. The flat plate surface temperature was measured using thermochromic liquid crystals. The results show that the film cooling is the main mechanism for the local cooling with a very low thermal conductivity while the convection heat transfer of the coolant in the coolant channel is the dominant heat transfer mechanism for the high thermal conductivity plate, with both film cooling and convection heat transfer by the coolant being important with medium thermal conductivity walls.     

Crystallinity and dielectric relaxations in semi-crystalline poly(ether ether ketone)

The Maxwell-Wagner-Sillars (MWS) relaxation is studied for semi-crystalline polymers poly (ether ether ketone) (PEEK), in the range 20 Hz-1 MHz and temperature varying from 80 to 330 °C. The parameter is the crystallization condition in the case of PEEK, which is a semi-crystalline polymer considered as a particulate composite. The relaxation found in the semi-crystalline polymers above the α relaxation of the PEEK is ascribed to the trapping of conductive carriers at the interface between crystalline lamellae and the amorphous matrix. The study of PEEK microstructure is based on differential calorimetry and X-rays diffraction. Two lamellae populations have been detected, that depends on the crystallization temperature and its duration. The crystallinity rate is increasing with crystallization temperature and duration. In dielectric studies, the use of the electric modulus instead of permittivity allows us to minimize the ionic conduction and then leads to the appearance of the interfacial relaxation. According to our measurements, the crystallinity rate is not the main factor of the interfacial relaxation intensity, which also depends on the nature and degree of perfection of the lamellae.