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81.
A reaction of dithiocarbamic acid salts with carbonyl compounds was investigated for the first time in the presence of BF(3)·OEt(2). The reaction is temperature dependent and gives gem-bis(dithiocarbamates) at 35-45 °C as a molecule with high equivalents of dithiocarbamate groups. At lower temperatures (15-20 °C), the 2-iminium-1,3-dithietane is obtained as the only product. The structure of a 2-iminium-1,3-dithietane was accomplished by X-ray crystallographic analysis.  相似文献   
82.
In this paper we used the Stokes shift phenomena to determine the difference in the dipole moments of the excited state micro(e) and ground state micro(g) to be (micro(e)-micro(g)), and the polarizability alpha. In this paper, we studied six different laser dyes belonging to four different classes of laser dyes which are diolefin 2,5-Distyryl pyrazine (DSB); 1,4-Bis (-pyridyl-2-vinyl) benzene (P2VB) and p-Bis-(o-methylstyryl)-benzene (Bis-MSB) with (micro(e)-micro(g)) equal to 6.40, 6.70 and 2.98 Debye, respectively; anthracene class includes 10(4-acetoxyphenyl)-2-methyl-9-acetoxy anthracene (APMAA) with (micro(e)-micro(g)) value of 7.25 Debye; Rhodamine B (RB) with (micro(e)-micro(g)) value of 5.33 Debye; and Coumarin 120 (C120) with the value 3.97 Debye for (micro(e)-micro(g)). In addition the value of both polarizability alpha and the radius r of each investigated laser dye molecule are determined. Therefore, the ratio alpha/r(3) for each dye is calculated to be 0.93, 0.79, 0.39, 0.37, 0.67 and 0.76 for DSP, P2VB, Bis-MSB, APMAA, RB and C120, respectively. The values of r are 4.83, 4.83, 4.90, 5.34, 5.75 and 4.11 A for the above consequence laser dyes. These dyes are studied in a large number of different solvents. The values obtained of (micro(e)-micro(g)) for these selected dyes are positive, which means that the excited state is more polar than the ground state.  相似文献   
83.
A new method for the estimation of lead, based on its oxidation from the bivalent to the quadrivalent state by alkaline permanganate has been devised. The reaction takes place so rapidly in the presence of a mixture of ZnO and HgO that it can be followed potentiometrically. Oxidation of sodium plumbite with KMn04 leads to the formation of PbO and MnO. Reduction of KMnO4 with Pb+2 ions or with sodium plumbite proceeds almost quantitatively in 2.5N NaOH in the absence of Ba+2 ions and in 1–1.5N NaOH in the presence of these ions. Under these conditions Pb+2 Pb+1 and Mn04 MnO4-2, provided that the lead solution is not added too rapidly.  相似文献   
84.
This study aims to understand the influence of relational benefits of Facebook brand/fan page towards relationship commitment among Generation Y. Additionally, this study also investigates the mediating effect of customer satisfaction on the relationship between relational benefits and relationship commitment. A total of 195 sets of online questionnaire were collected using snowball sampling method for the statistical data requirement of SmartPLS. The analysis found significant positive relationships between relational benefits and relationship commitment, however, only on social, functional, and special treatment benefits. Surprisingly, the findings also showed an insignificant mediation effect of customer satisfaction on the relationship between relational benefits and relationship commitment. The research findings are valuable to both the theoretical and businesses adopting social media as a marketing strategy. Marketers employing the Facebook or other social media in catering and reacting to the Generation Y needs will benefit the most; securing their confidence and loyalty towards purchasing a certain brand.  相似文献   
85.
Summary A spectrophotometric method for determination of beryllium ing quantities is described which is based on color reaction between beryllium and rufigallol having maximum absorption at 530 nm. Comparing various solvents, the suitable medium found is DMSO-H2O (3 2). Interference of Al, Zr, Th, Hf and many other cations have been removed by solvent extraction of their oxinates with chloroform.
Zusammenfassung Eine spektrophotometrische Bestimmungsmethode für Mikrogrammmengen Be wurde beschrieben, die auf der Farbreaktion mit Rufigallol mit einem Absorptionsmaximum bei 530 nm beruht. Als geeignetes Medium erwies sich Dimethylsulfoxid in Wasser (3 2). Störende Kationen wie Al, Zr, Th, Hf und viele andere werden in Form ihrer Oxinate mit Chloroform extrahiert.
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86.
Phenol‐based acyclic ligand 1,6‐bis(2‐chlorobenzyl)‐2,5‐bis(2‐hydroxy‐3‐formyl‐5‐methylbenzyl)‐2,5‐diazahexane, LH2 and its dilithium form Li2L possessing two dissimilar compartments having multifunctional groups were prepared through a Mannich reaction. To synthesize this ligand first, diamine compound 1,6‐bis(2‐chlorobenzyl)‐2,5‐diazahexane was prepared and then in a one‐step procedure an equivalent of diamine and two equivalents of 4‐methyl‐2‐formylphenol in the presence of an excess amount para‐formaldehyde were reacted. All characterization data for the new compounds including diimine, diamine, LH2 and Li2L are reported.  相似文献   
87.
The structural and magnetic properties of amorphous ferromagnetic microwires can undergo significant measurements under the action of external mechanical stresses and heat treatment. The study of transformations occurring in this case is important for designing various sensors of mechanical stresses, loading, and temperature and also for inducing in the wires a certain type of magnetic anisotropy that plays a significant role in the realization of various effects in them. In this work, the influence of external stresses and annealing on the processes of the magnetization and the magnetic impedance of Co71Fe5B11Si10Cr3 microwires having a low positive magnetostriction (~10-8) in amorphous state has been studied. The influence of external stresses leads to a sharp change in the character of the magnetization reversal curve, which was due to the change in the sign of the magnetostriction and the type of magnetic anisotropy. The amplitude of higher harmonics and the value of the magnetic impedance, respectively, are sensitive to mechanical stresses. Elastic stresses in the wires with a partial crystallization do not lead to a marked change in the magnetic properties; however, annealing can lead to a substantial increase in the axial magnetic anisotropy of the wires existing in the stressed state. The experimental results are analyzed in the framework of a magnetostriction model of induced magnetic anisotropy.  相似文献   
88.
We developed a plasmonic refractive index (RI) with a metal-dielectric-metal (MDM) structure that utilizes two Persian Orsi windows-like separated cavities with a high figure of merit (FoM) and ultrasensitivity. The simulated and optimized Ag-air-Ag MDM sensor for surface plasmon resonance (SPR) offers high RI sensitivity (SRI) and the ability to detect blood plasma concentration (BPC). The results verified that structural parameters have an effect on SRI, full width at half maximum (FWHM), FoM, sensitivity of blood plasma (Sp) for right and left peaks, whose values are 1 345.45 nm.RIU−1, 32 nm, 42.04 RIU−1, 0.26 and 0.19 nm.L.g-1, respectively. The proposed design opens a new horizon in sensor development.  相似文献   
89.

Improving heat transfer is a critical subject for energy conservation systems which directly affects economic efficiency of these systems. There are active and passive methods which can be employed to enhance the rate of heat transfer without reducing the general efficiency of the energy conservation systems. Among these methods, passive techniques are more cost-effective and reliable in comparison with active ones as they have no moving parts. To achieve further improvements in heat transfer performances, some researchers combined passive techniques. This article performs a review of the literature on the area of heat transfer improvement employing a combination of nanofluid and inserts. Inserts are baffles, twisted tape, vortex generators, and wire coil inserts. The progress made and the current challenges for each combined system are discussed, and some conclusions and suggestions are made for future research.

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90.
A semi-circular patch antenna (SCPA) is designed for WiMAX and WiFi-5/6 communications. The footprint of the proposed SCPA is only 30 × 40 × 1.575 mm3, which is composed of a semi-circular patch and a partial ground plane. The main strength of this work is that the estimated wide dual-frequency span of 2.39–3.75 GHz and 5.39–7.18 GHz are contributed with two sharp resonances at 2.77 and 6.46 GHz, respectively. The proposed SCPA has been practically tested after fabrication. The measured results confirm that the designed antenna achieved the bandwidth necessity for WiMAX 1.5 (2.5–2.69 GHz), WiMAX 2 (3.4–3.6 GHz), WiFi-5 (5.15–5.85 GHz) and WiFi-6 (5.925–7.125 GHz). In the two resonance frequencies of 2.77 and 6.46 GHz, the designed antenna achieved a gain of 2.558 and 4.109 dB, respectively. In addition, the SCPA also manifests good radiation properties and achieves an average efficiency of more than 90%. A professional version of the 3D electromagnetic simulator is utilized to examine the effect of diffident parameters and model the tested antenna.  相似文献   
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