Lead Method Research Articles

Nature of Beryllium, Magnesium, and Zinc Bonds in Carbene⋯MX2 (M = Be, Mg, Zn; X = H, Br) Dimers Revealed by the IQA, ETS-NOCV and LED Methods.

The nature of beryllium−, magnesium− and zinc−carbene bonds in the cyclopropenylidene⋯MX2 (M = Be, Mg, Zn; X = H, Br) and imidazol-2-ylidene⋯MBr2 dimers is investigated by the joint use of the topological QTAIM-based IQA decomposition scheme, the molecular orbital-based ETS-NOCV charge and energy decomposition method, and the LED energy decomposition approach based on the state-of-the-art DLPNO-CCSD(T) method. All these methods show that the C⋯M bond strengthens according to the following order: Zn < Mg << Be. Electrostatics is proved to be the dominant bond component, whereas the orbital component is far less important. It is shown that QTAIM/IQA underestimates electrostatic contribution for zinc bonds with respect to both ETS-NOCV and LED schemes. The σ carbene→MX2 donation appears to be much more important than the MX2→ carbene back-donation of π symmetry. The substitution of hydrogen atoms by bromine (X in MX2) strengthens the metal−carbene bond in all cases. The physical origin of rotational barriers has been unveiled by the ETS-NOCV approach.

Electrodeposition of Lead from Simulated Wastewater Using Stainless Steel Tubes Bundle as Cathode

Background: Lead ions form a dangerous pollutant to both human and aqua lives when discharged to the environment with wastewater due to the diseases and the damage of the live cells caused by these ions, so, it is very important to find an effective method for lead ions removel. Methodology: Lead ions were successfully recovered from simulated wastewater by a flowthrough batch recycle electrochemical reactor with stainless steel tubes bundle as a cathode operating under mass transfer control conditions in 0.5 M NaCl electrolyte solution. Effects of initial lead ions concentration, electrolyte flow rate, and PH were studied and the mass transfer coefficient was determined under these conditions. Performance of this reactor was analyzed by the construction of some figures of merit like fractional conversion, specific energy consumption, space-time yield, and space velocity. Results: Experimental results were correlated in the general form of a dimensionless mass transfer correlation as SH = 1.024Re0.00699Sc1/3.

Bulk Etch Rate Measurement of Cr-39 Detector at Constant Normality Using The Diameters and The Lengths of The Tracks of Α-Particles

The aim of this paper is to determine the bulk etch rate of Nuclear Track Detector (type CR-39) using the track’s diameter-length (Le-D) measurement method by irradiating the detector with different energies of alpha particles from 241Am source. Constant normality (6.25) N of the chemical solution NaoH at a temperature of (70±1) oC is used in etching the detectors to measure the track’s lengths and it’s diameter at different etching times corresponding to the energy of the incident’s particles. The bulk etch rate VB values of CR-39 detector have been found by using Le-D method are (1.4228, 1.2563, 1.5098, 1.438) µm.hr-1 and they showed good agreement with the values measured by the removed layer method which were (0.944-1.831) µm.hr-1.

Current mode LED Driving Circuit using Asymptotic Method

In this paper, it was supposed to current mode design included to required current of ideal LED, through asymptotic method for LED driving. LEDs current characteristic has exponential function, and implementation of driving circuit exists problems. However, it can be designed to linear current source through asymptotic method for ideal required current Proposed LED driving circuits was confirmed the linearity to switched input constant current sources, and driving circuits was designed to satisfy the LED current requirement. Proposed circuit has LSB corresponding to 800μA in 9.6um width and confirmed by Dong- Bu 0.35um CMOS process.

A New Method of Real-Time Detecting the Chlorophyll Based on Hover Wing UAV

A fluorescent real-time detection technology parameters of the chlorophyll radiation LED method using with fluorescent MINIPAM based on impulse, modulation, is introduced. The using of programming power to provide a constant flow of the list of output, LED by a matrix as chlorophyll are fluorescent light. The using of apparatus in plant MINIPAM fluorescent light system II of the steady state Fs, a fluorescent light to the next largest fluorescent Fm',a combination of the environment, and tracking control system of measurement and comprehensive analysis of environmental factors to the real quantum efficiency, actual electronic transmission rate for parameters. MINIPAM fluorescent apparatus with the upper machine, and can be real time monitoring.

Epitaxial growth of III–V compound semiconductor thin films and their device applications

Recent adances in crystal growth and thin-film growth of SiC; scaling up the size of ingots; comparison of CVD, MBE and LED methods.