Efficiency shift in very high efficiency GaP (Zn–O) diodes

1972 ◽  
Vol 21 (6) ◽  
pp. 257-260 ◽  
Author(s):  
R. Solomon ◽  
D. DeFevere
Keyword(s):  
High Efficiency ◽  
Efficiency Gap ◽  
Very High

Very High Efficiency GaP Green Light Emitting Diodes

1975 ◽  
Vol 122 (3) ◽  
pp. 407-412 ◽  
Author(s):  
O. G. Lorimor ◽  
P. D. Dapkus ◽  
W. H. Hackett
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Green Light ◽  
Light Emitting ◽  
Efficiency Gap ◽  
Very High

ChemInform Abstract: VERY HIGH EFFICIENCY GAP GREEN LIGHT EMITTING DIODES

1975 ◽  
Vol 6 (26) ◽  
pp. no-no
Author(s):  
O. G. LORIMOR ◽  
P. D. DAPKUS ◽  
W. H. JUN. HACKETT
Keyword(s):  
High Efficiency ◽  
Light Emitting Diodes ◽  
Green Light ◽  
Light Emitting ◽  
Efficiency Gap ◽  
Very High

scholarly journals Near quantitative synthesis of urea macrocycles enabled by bulky N-substituent

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yingfeng Yang ◽  
Hanze Ying ◽  
Zhixia Li ◽  
Jiang Wang ◽  
Yingying Chen ◽  
...  
Keyword(s):  
High Efficiency ◽  
Molecular Structures ◽  
High Yield ◽  
Kinetic Control ◽  
High Concentration ◽  
Weak Association ◽  
Quantitative Synthesis ◽  
Thermodynamic Stabilization ◽  
Discrete Structures ◽  
Very High

AbstractMacrocycles are unique molecular structures extensively used in the design of catalysts, therapeutics and supramolecular assemblies. Among all reactions reported to date, systems that can produce macrocycles in high yield under high reaction concentrations are rare. Here we report the use of dynamic hindered urea bond (HUB) for the construction of urea macrocycles with very high efficiency. Mixing of equal molar diisocyanate and hindered diamine leads to formation of macrocycles with discrete structures in nearly quantitative yields under high concentration of reactants. The bulky N-tert-butyl plays key roles to facilitate the formation of macrocycles, providing not only the kinetic control due to the formation of the cyclization-promoting cis C = O/tert-butyl conformation, but also possibly the thermodynamic stabilization of macrocycles with weak association interactions. The bulky N-tert-butyl can be readily removed by acid to eliminate the dynamicity of HUB and stabilize the macrocycle structures.

Design and Analysis of a High Pitch to Chord Ratio Cascade Representative of Ducted Propfans

1991 ◽  
Author(s):  
A. Weber ◽  
W. Steinert ◽  
H. Starken
Keyword(s):  
Boundary Layer ◽  
Mach Number ◽  
High Efficiency ◽  
Pressure Ratio ◽  
Flow Analysis ◽  
High Pitch ◽  
Integral Boundary ◽  
Pressure Loss Coefficient ◽  
Distribution Boundary ◽  
Very High

Efforts to reduce the specific fuel consumption of a modern aero engine focus in particular on increasing the by-pass ratio beyond the current level of around 5. One concept is the counterrotating shrouded propfan operating at low overall pressure ratio and having only very few fan blades of extremely high pitch/chord ratios. The relative inlet Mach numbers cover a range from 0.7 at the hub to 1.1 at the tip section of the first rotor. A propfan cascade was designed by taking into account two characteristic features of a propfan blade-blade section: • a very high pitch/chord ratio of s/c = 2.25 • an inlet Mach number of M1 = 0.90 which leads to transonic flow conditions inside the blade passage In the design process a profile generator and a quasi-3D Euler solver were used iteratively to optimize the profile Mach number distribution. Boundary layer behavior was checked with an integral boundary layer code. The cascade design was verified experimentally in the transonic cascade wind tunnel of DLR at Cologne. The extensive experimental results confirm the design goal of roughly 5 degree flow turning. A total pressure loss coefficient of less than 1.5% was measured at design conditions. This validates the very high efficiency level the propfan concept is calling for. A 2D Navier-Stokes flow analysis code yields good results in comparison to the experimental ones.

scholarly journals Instantaneous Electromagnetic Torque Components in Synchronous Motors Fed by Load-Commutated Inverters

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3223
Author(s):  
Gabriel Ekemb ◽  
Fouad Slaoui-Hasnaoui ◽  
Joseph Song-Manguelle ◽  
P. M. Lingom ◽  
Issouf Fofana
Keyword(s):  
High Efficiency ◽  
Air Gap ◽  
International Standards ◽  
Synchronous Motors ◽  
Gas Compression ◽  
Variable Frequency Drives ◽  
Torsional Analysis ◽  
Analytical Expressions ◽  
Very High ◽  
Excitation Circuit

This paper proposes time-domain analytical expressions of the instantaneous pulsating torque components in a synchronous machine air gap when supplied by a load-commutated-inverter (LCI) system. The LCI technology is one of the most used variable frequency drives when very high power and low speed are required in applications such as pipeline recompression and decompression, as well as liquefied natural gas compression. In such applications, synchronous motors are used because of their high efficiency resulting from a separated supply of the current to their rotor through the excitation circuit. These applications usually have long and flexible shafts, which are very sensitive to torsional vibration excitation when their natural frequencies interact with any external torque applied to the shaft. A torsional analysis is required by international standards to assess the survivability of the shaft through the overall speed range of the motor. Therefore, the magnitude and frequencies of the motor air-gap torque are needed for such evaluation. The proposed developments are supported by numerical simulations of LCI systems in a large range of operation range. From the simulation results, torque harmonic families are derived and expressed in a parametric form, which confirm the accuracy of the proposed relationships.

scholarly journals The use of the method of controlling the electrochemical parameters of aqueous solutions to combat complications in the operation of oil field pipelines

2021 ◽  
Vol 225 ◽  
pp. 01008
Author(s):  
Oleg Latypov ◽  
Sergey Cherepashkin ◽  
Dina Latypova
Keyword(s):  
Aqueous Solutions ◽  
Oil And Gas ◽  
High Efficiency ◽  
Oil Field ◽  
Oil Fields ◽  
Control Methods ◽  
Test Results ◽  
Chemical Reagents ◽  
Electrochemical Parameters ◽  
Very High

Corrosion of equipment in the oil and gas complex is a global problem, as it contributes to huge material costs and global disasters that violate the environment. Corrosion control methods used to protect equipment do not always ensure the absolute safety of the operation of oil and gas facilities. Moreover, they are quite expensive. The developed method for controlling the electrochemical parameters of aqueous solutions to combat complications during the operation of oil-field pipelines provides the necessary protection against corrosion. The method is economical and environmentally friendly, since it does not require the use of chemical reagents. The test results have shown a very high efficiency in dealing with complications in oil fields.

scholarly journals The Use of Hyaluronic Acid Combined with Teosyal Redensity II for the Treatment of Dark Circles Under the Eyes

2017 ◽  
Vol 54 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Valeriu Ardeleanu ◽  
Sorin Ioan Berbece ◽  
Ioan Petre Florescu ◽  
Radu Cristian Jecan
Keyword(s):  
Hyaluronic Acid ◽  
High Efficiency ◽  
Cumulative Effects ◽  
Major Improvement ◽  
Safe Product ◽  
Very High

This study intends to highlight the results of the product Teosyal Redensity II through the cumulative effects of its constituents, that have an antioxidant, hydrating, filling and facial restructuring role. The study was performed in the Arestetic Clinic, Galai, between 07.12.2015 and 07.12.2016 on a group of 49 patients, of which 43 women and 6 men. Teosyal Redensity 2 proved to be a safe product - as long as it is injected correctly, it does not cause complications. It�s easy to inject and has a very high efficiency. It�s a periorbital rejuvenation and restructuring product, with a filling, antioxidant, hydration and dermal redensification effect. In the case of persons that needed a second injection after 1 month, one could observe a major improvement in elasticity and firmness felt by the person performing the injection. The injection requires small quantities of the substance and is accompanied by only mild discomfort. The result is visible right away.

scholarly journals Production of Sm-153 With Very High Specific Activity for Targeted Radionuclide Therapy

2021 ◽  
Vol 8 ◽  
Author(s):  
Michiel Van de Voorde ◽  
Charlotte Duchemin ◽  
Reinhard Heinke ◽  
Laura Lambert ◽  
Eric Chevallay ◽  
...  
Keyword(s):  
Neutron Irradiation ◽  
Radionuclide Therapy ◽  
High Efficiency ◽  
Separation Efficiency ◽  
Specific Activity ◽  
High Specific Activity ◽  
Mass Separation ◽  
Full Potential ◽  
Targeted Radionuclide Therapy ◽  
Very High

Samarium-153 (153Sm) is a highly interesting radionuclide within the field of targeted radionuclide therapy because of its favorable decay characteristics. 153Sm has a half-life of 1.93 d and decays into a stable daughter nuclide (153Eu) whereupon β− particles [E = 705 keV (30%), 635 keV (50%)] are emitted which are suitable for therapy. 153Sm also emits γ photons [103 keV (28%)] allowing for SPECT imaging, which is of value in theranostics. However, the full potential of 153Sm in nuclear medicine is currently not being exploited because of the radionuclide's limited specific activity due to its carrier added production route. In this work a new production method was developed to produce 153Sm with higher specific activity, allowing for its potential use in targeted radionuclide therapy. 153Sm was efficiently produced via neutron irradiation of a highly enriched 152Sm target (98.7% enriched, σth = 206 b) in the BR2 reactor at SCK CEN. Irradiated target materials were shipped to CERN-MEDICIS, where 153Sm was isolated from the 152Sm target via mass separation (MS) in combination with laser resonance enhanced ionization to drastically increase the specific activity. The specific activity obtained was 1.87 TBq/mg (≈ 265 times higher after the end of irradiation in BR2 + cooling). An overall mass separation efficiency of 4.5% was reached on average for all mass separations. Further radiochemical purification steps were developed at SCK CEN to recover the 153Sm from the MS target to yield a solution ready for radiolabeling. Each step of the radiochemical process was fully analyzed and characterized for further optimization resulting in a high efficiency (overall recovery: 84%). The obtained high specific activity (HSA) 153Sm was then used in radiolabeling experiments with different concentrations of 4-isothiocyanatobenzyl-1,4,7,10-tetraazacyclododecane tetraacetic acid (p-SCN-Bn-DOTA). Even at low concentrations of p-SCN-Bn-DOTA, radiolabeling of 0.5 MBq of HSA 153Sm was found to be efficient. In this proof-of-concept study, we demonstrated the potential to combine neutron irradiation with mass separation to supply high specific activity 153Sm. Using this process, 153SmCl3 suitable for radiolabeling, was produced with a very high specific activity allowing application of 153Sm in targeted radionuclide therapy. Further studies to incorporate 153Sm in radiopharmaceuticals for targeted radionuclide therapy are ongoing.

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