In conventional quantum-well lasers, carriers are injected into the quantum wells with quite high energies. We have investigated lasers in which electrons ground state through tunneling. The tunneling injection shown to negligible gain compression, superior high-temperature performance, lower Auger recombination and wavelength chirp, better modulation characteristics when compared lasers. underlying physical principles behind performance also explored, calculations measurements of relaxation...

This paper demonstrates signal-to-noise ratio (SNR) improvement of an optical time-domain reflectometer (OTDR) using simplex codes (scs) for the first time. By developing a generalized procedure analysis noise transfer in coded OTDR employing L-bit scs, SNR dependence on receiver bandwidth is also investigated. Experimental results obtained from constructed sc-OTDR showed excellent agreement with theoretical over entire code lengths. Improvement up to 9.2 dB has been demonstrated 255-bit scs.

The pretreatment processes consisting of grinding followed by roasting were investigated to improve the selective leaching Nd and Dy from neodymium-iron-boron (NdFeB) magnet scraps. peaks Nd(OH)3 Fe observed in XRD results after with NaOH as amount water addition increased 5 cm3. These indicate that components NdFeB could be changed successfully into Fe, respectively. In tests using ground product, increasing temperature 500 °C, disappeared while those Nd2O3 Fe2O3 shown. NdFeO3 sample...

Ion exchange separation of rhenium using Purolite A-170 and A-172 was carried out from the dust leach solution molybdenite concentrate. Different parameters such as effect contact time, equilibrium pH, solid liquid ratio were investigated. The optimum absorption condition for resin determined, efficiency Re Mo obtained to be about 90 0%, respectively. From results, it evident that, performance more effective than resin, towards selective recovery solution.

As technology keeps developing, India has become an emerging market in the world consuming lithium-ion battery (LIB) numerous applications such as portable electronics, energy storage system (ESS) and latest into electric vehicles. The high-end consumption of batteries would generate a significant quantity end-of-life coming seven to eight years. Currently, there is no dedicated legislation or infrastructure handle waste stream, which could be beneficial economically, environmentally...

In this study, deep eutectic solvents (DESs) were employed as environmentally friendly alternatives of inorganic acid to selectively leach REEs from waste NdFeB magnets. Three DESs tested, effective for light REE leaching, and preliminary experiments conducted study the selective leaching REEs, using synthetic materials, Nd2O3, Fe, Fe3O4, Fe2O3. The findings suggest that neodymium iron should exist Nd2O3 Fe2O3, respectively, leaching. To enhance magnet, three pretreatment methods applied:...

A1200N vacuum-thrust-class staged-bipropellant engine that uses decomposed hydrogen peroxide as an oxidizer and kerosene a fuel was developed tested with the aim of investigating axial injector integrated distributor. This geometry, where is injected into turbulent flow peroxide, to evaluate influence designed on performance respect equivalence ratio, pattern injection orifices, characteristic length L . For characteristics such autoignition stable combustion, firing tests over awide range...

The current study deals with the recovery process development for rare earths (REs), i.e., dysprosium (Dy) and neodymium (Nd), metals from permanent magnet scraps leach liquors.Its main objective is of (Dy Nd) (PMSs).Introdutory experiments were carried out to get liquor solution: oxidation/roasting, acid leaching, precipitation methods implemented PMSs dissolution.The obtained was diluted ten times used present study.Di-2-ethylhexyl phosphoric (D2EHPA) as an extractant REs kerosene diluent...

We propose a novel structure for C plus L-band silica based wide-band erbium-doped fiber amplifiers (W-EDFA's), which use backward amplified spontaneous emission from the C-band EDFA as pump-mediating injection source amplifier unit. Experimental results show gain and noise figure improvements of over 2.6 dB 0.6 dB, respectively, at -3.5 dBm input signal power. Spatially resolved numerical analysis confirms effect ASE in improvement, also provides better understanding on dynamics seed methods.

In a short time, IEEE EPON has progressed from initial trials to market-leading optical access technology that supports business and residential services, including IPTV, VoIP, commercial- grade data cellular backhaul. Due EPON's simplicity flexibility, various standards development organizations have embarked on standardization projects aimed at integrating with existing network architectures. Also, several operators developed solutions address their specific deployment environments or...

In this study, amine based extractants (Alamine 336, Alamine 308, 304 and Aliquat 336) diluted in kerosene were used as promising for uranium extraction separation from other associated elements. 336 was the best extractant process sulfate solutions when compared with extractants, 336. Synergistic behavior studied amines well synergists organophosphorus reagents synergist mixed amines. studies not suitable each better efficiency. However, gave positive synergetic highest synergistic...

The main objective of the present study is to separate rhenium and molybdenum as well recovery targeted metal ion. behavior extraction, stripping separation possibilities from molybdenite roasting dust leaching solutions using tri-otyl-amine (TOA) an extractant has been investigated. From results, 5 vol% TOA dissolved in kerosene found be selective for extraction compared with molybdenum. It extracted, efficiency less than 30%, whereas more ∼99%. optimum conditions have determined as: TOA,...

The aim of the present study is to investigate extraction, separation and recovery indivisible metals dysprosium neodymium from permanent magnets scrap (PMS) leach liquor solutions. Organo-phosphorous extractant namely 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC 88A) was employed optimised various experimental parameters recover dysprosium. development focused on Dy Nd by suitable mineral acids. Fundamental studies effect time, pH concentration metal were conducted followed...

We have analyzed the effectiveness of two different polarization-mode dispersion (PMD) compensators in high-speed transmission systems suffering from polarization-dependent loss (PDL). When link PDL value increases, system performance improvement decreases. Numerical analysis a 10-Gb/s shows that even small average 0.5 dB could seriously limit PMD compensations.

We examine the performance of optical 8-ary differential phase-shift keying transmission systems according to type receiver structure and modulation format. Compared with approach based on a multilevel decision, we found that bilevel provides 3-dB gain in signal-to-noise ratio sensitivity is more robust against chromatic dispersion for either nonreturn-to-zero or return-to-zero modulation.