The hexa-coordinated chelate complexes of the type [Ru(CO)2Cl2(P-P)](1a,b) [where P-P = 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene(a) and [bis(2-diphenylphosphinophenyl)ether(b)] have been synthesized by reacting the polymeric precursor [Ru(CO)2Cl2]n with the ligands in 1:1 molar ratio. The complexes 1a,b are characterized by elemental analyses, Mass, IR and NMR spectroscopy together with the single crystal X-ray structure determination of 1a. The compound 1a crystallizes in a monoclinic system with space group C2/c showing a slightly distorted octahedral geometry around the Ru centre. The complexes 1a and 1b are thermally stable up to 300 °C and exhibit high catalytic activity in transfer hydrogenation of aldehyde and ketones to corresponding alcohols. The complexes 1a and 1b show much higher catalytic activity for the hydrogenation of aldehyde than ketones. In general, the catalytic efficiency of 1b is higher compared with 1a. 相似文献
The development and photoluminescence analysis of Eu3+or Dy3+ ions in the matrix of lithium titanate (Li2TiO3) ceramics by using a solid state reaction method are reported. Emission spectra of Eu3+:Li2TiO3 ceramics have shown strong red emission at 611 nm (5D0 → 7F2) with λexci = 392 nm (7F0 → 5L6) and from the Dy3+:Li2TiO3, a blue emission at 493 nm (4F9/2 → 6H15/2) and also an yellow emission at 582 nm (4F9/2 → 6H13/2) have been observed with λexci = 366 nm (6H15/2 → 6P5/2). Both the rare-earth ions containing ceramics have displayed their brighter emission performance from their measured spectral results. In addition, X-ray diffraction (XRD), Fourier transform infra red (FTIR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) have been used to characterize the structural properties of (Eu3+ or Dy3+):Li2TiO3 ceramics. 相似文献
The aquatic environment around the textile industries in India was severely affected due to continuous discharge of effluents. In order to avoid further deterioration, the pollution control board of Tamil Nadu, India has enforced zero discharge concepts throughout the state. Consequently, most of the industries have opted membrane technology to recover water. The present study was aimed to find out the efficacy of electrochemical techniques as pretreatment methods to reverse osmosis (RO). The textile wastewater was initially treated by electrocoagulation to remove the suspended solids. After the electrocoagulation, the wastewater was further treated by electrooxidation for COD removal. Mild steel as anode was found to be effective for coagulation of suspended solids. For electrooxidation, graphite and RuO2/IrO2/TaO2 coated titanium were used as electrodes. The efficiency of these electrode materials was evaluated in terms of chemical oxygen demand (COD) removal, instantaneous current efficiency (ICE) and electrooxidation index (EOI). The COD was removed to the extent of 90-93% using graphite and 54% with RuO2/IrO2/TaO2 coated titanium electrodes. The current efficiency of 40% and 11% was achieved with graphite and RuO2/IrO2/TaO2 coated titanium respectively. The degradation of organics was followed using GC-MS and the reason for incomplete degradation of organics in the presence of RuO2/IrO2/TaO2 coated titanium was discussed. 相似文献
In this paper, a closed-form expression for the probability of error in a coherent BPSK system over Generalized Rayleigh fading
channels is derived. An L-branch equal gain combining diversity scheme is used. Theoretical results for the probability of error are plotted for various
values of the number of degrees of freedom (n) and diversity order (L). A simulation is performed and the simulated results are found to match very well with the theoretical results.
The Journal of Supercomputing - Recent advancements in edge computing devices motivate us to develop a sustainable and reliable technique for multiple gait activities recognition using wearable... 相似文献
Wireless Personal Communications - Complementary coded code-division multiple access (CC-CDMA) has been originated as one of the extremely robust multiuser access technique in designing high data... 相似文献
This research work aims to investigate the inter-correlation between microstructure, thermal (thermal conductivity, thermo-gravimetric analysis), thermo-mechanical (dynamic mechanical analysis) and fracture characteristics of hybrid AA2024-SiC alloy composites fabricated via semi-automatic stir-casting process, as per standard industrial practice. Silicon Carbide (SiC) particulates of varying amount (0–6 wt%; @ step of 2%) were used to reinforce master batch of AA2024 wrought alloy, Silicon Nitride (Si3N4) and graphite particulates. The thermal conductivity and storage-modulus magnitudes of alloy composites have shown diminishing trend with hard SiC reinforcing phase, while material stability, viscous modulus, damping factor and fracture toughness have shown significant improvement. Uniform dispersion and better interfacial adhesion between matrix–reinforcement were observed from metallographic examination. The XRD analysis identified the different phases of the hybrid alloy composites. The trends in variations of physical, mechanical and tribological properties were supported by microstructure analysis, thermal analysis, thermo-mechanical analysis and fracture analysis. 相似文献
Triboelectric nanogenerators (TENGs) are gaining much research interest recently owing to their facile and cost‐effective device structure. However, the effect of relative humidity (in moisture atmosphere) on the output performance still needs to be resolved. Herein, a pouch‐type TENG is proposed to significantly reduce the effect of relative humidity on its electrical output and a stable performance is also attained in a humid environment. In this regard, a dielectric and dielectric materials‐based TENG (DD‐TENG) is first developed using nanoarchitecture polydimethylsiloxane (NA‐PDMS) and multiwalled carbon nanotube/nylon composite layers as a triboelectric material with the negative and positive tendencies, respectively. The NA‐PDMS and nylon composite layers play a key role in increasing the surface contact area and surface charge density between the dielectric/triboelectric materials as well as the output performance of DD‐TENG. However, the DD‐TENG device exhibits a stable and high output performance with the effective output power density of ≈25.35 W m?2. Additionally, the performance of the pouch‐type DD‐TENG device is not almost affected even though the relative humidity is increased from 35 to 81%, while it is dramatically decreased for the nonpouch‐type device. Finally, the pouch‐type DD‐TENG is employed as a wearable device to effectively harvest the mechanical energy from daily human activities. 相似文献
In this article, a circularly polarized antenna for ultra‐high frequency radio frequency identification (RFID) tag is presented. The circular polarization is realized by two orthogonal, unequal length linearly tapered meander line cross dipoles. The meander structure with capacitive tip loading is used for size miniaturization of the antenna. A modified T‐match network is employed to feed the cross dipole structure. The measured 10‐dB return loss bandwidth of the cross dipole antenna is 17 MHz (908‐923 MHz) and the corresponding 3‐dB axial ratio bandwidth is 6 MHz (912‐918 MHz). The overall size of the proposed antenna is 0.17λ0 × 0.17λ0 at 915 MHz. The maximum read range between the reader and the tag with the proposed antenna is 4.7 m larger than the analogous linearly polarized tag antenna due to the reduction in polarization loss between the tag and reader antennas. Thus, a maximum read range of 15.66 m with the gain of 1.28 dBic is achieved at 915 MHz. 相似文献
In cloud computing, more often times cloud assets are underutilized because of poor allocation of task in virtual machine (VM). There exist inconsistent factors affecting the scheduling tasks to VMs. In this paper, an effective scheduling with multi-objective VM selection in cloud data centers is proposed. The proposed multi-objective VM selection and optimized scheduling is described as follows. Initially the input tasks are gathered in a task queue and tasks computational time and trust parameters are measured in the task manager. Then the tasks are prioritized based on the computed measures. Finally, the tasks are scheduled to the VMs in host manager. Here, multi-objectives are considered for VM selection. The objectives such as power usage, load volume, and resource wastage are evaluated for the VMs and the entropy is calculated for the measured objectives and based on the entropy value krill herd optimization algorithm prioritized tasks are scheduled to the VMs. The experimental results prove that the proposed entropy based krill herd optimization scheduling outperforms the existing general krill herd optimization, cuckoo search optimization, cloud list scheduling, minimum completion cloud, cloud task partitioning scheduling and round robin techniques.