Current Issue : October - December Volume : 2018 Issue Number : 4 Articles : 5 Articles
This paper presents a new current conveyor (CCII+) full-wave rectifier for\nlow frequency/small signal medical applications. The proposed rectifier is\nbased on the current conveyor full-wave rectifier proposed previously, but the\nproposed rectifier is better in view of no need diodes to rectify, and no need\nbias sources to overcome the zero crossing error. It needs only two CCII+s,\ntwo resistors, and three simple current mirrors, which is easy for IC implementation\nand for building in many countries. The PSPICE simulation with\nthe current conveyor CCII+ in the current feedback opamp AD844 IC and the\n2N2222 bipolar current mirror shows the good low frequency/small signal\nrectification, the operation voltage of down to 6 V ....
Fishermen generally use light as a common way to attract fish in the fishing\nindustry. This study aimed to design a model of an underwater fishing using\nLight Emitting Diode (LED) lamp which is less costful and suitable for fishermen\nof Tanzania. Most fishermen currently use kerosene based lamps like\ncandela which consumes lots of energy leading to high cost in terms of money\nused to regenerate the energy. This running cost automatically rises up the\nprice of fish in the market. Thus with the use of LED lamp the cost will be reduced.\nThe findings from this study showed that the LED lamp consumes little\namount of energy (energy saving) compared to candela lamp which consumes\n6 liters of kerosene per 36 hours which is equivalent to three nights,\nwhile the LED lamp takes 7 batteries at once for 36 hours. The 6 liters of kerosene\ncost around 7 USD and that of 7 batteries cost is near 2 USD. The LED\nlamp can be accessed by only 15 USD the price which is nearly half the price\nof the candela lamp. The candela lamp in the market is sold around 31 USD.\nThis shows that LED lamp is more efficient in terms of conserving energy and\ncost effective than candela lamp. It is recommended that fishermen in the\nfishing industry in Tanzania should employ the usage of underwater LED\nfishing lamps as they are energy efficient. This will help the fishermen of\nTanzania to undertake the fishing activity at low cost which will result to the\ndecrease of price of fish in the market. This shows that this LED lamp has\nhigh efficiency and effectiveness to be used by fishermen compared to traditional\nmethod used by majority of them....
We investigate the cause of the optoelectronic performance variations in InGaN/GaN\nmultiple-quantum-well blue light-emitting diodes, using three different samples from an identical\nwafer grown on a c-plane sapphire substrate. Various macroscopic measurements have been\nconducted, revealing that with increasing strain in the quantum wells (QWs), the crystal quality\nimproves with an increasing peak internal quantum efficiency while the droop becomes more severe.\nWe propose to explain these variations using a model where the in-plane local potential fluctuation\nin QWs is considered. Our work is contrasted with prior works in that macroscopic measurements\nare utilized to find clues on the microscopic changes and their impacts on the device performances,\nwhich has been rarely attempted....
In this study, a series of bipolar fluorescence emitters named 2DPAc-OXD, DPAc-OXD,\n2PTZ-OXD and PTZ-OXD were designed and synthesized with excellent yields. The characterization\nof materials was investigated by using nuclear magnetic resonance (NMR) (1H, 13C), mass\nspectrometry and thermogravimetric analysis (TGA). To investigate device efficiencies, two different\nOLED devices (Device 1, Device 2) were fabricated with two different host materials (Bepp2, DPEPO).\nThe Device 2 with 2PTZ-OXD as fluorescent emitter exhibited excellent power and current efficiencies\nof 6.88 Lm/W and 10.10 cd/A, respectively. The external quantum efficiency of 2PTZ-OXD was\naround 3.99% for Device 2. The overall device properties of phenothiazine donor were better than\nacridine derivatives....
The sodium cobaltate system NaxCoO2 is a prominent representant of strongly correlated materials with promising thermoelectric response. In a combined theoretical and experimental study we show that, by doping the Co site of the compound at x =0.7 with iron, a further increase of the Seebeck coefficient is achieved. The Fe defects give rise to effective hole doping in the highthermopower region of larger sodium content x. Originally filled hole pockets in the angular-resolved spectral function of the material shift to low energy when introducing Fe, leading to a multisheet interacting Fermi surface. Because of the higher sensitivity of correlated materials to doping, introducing adequate substitutional defects is thus a promising route to manipulate their thermopower....
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