A High-performance 65 W Universal ac-dc Converter Using a Variable-Inverter-Rectifier-Transformer with Improved Step-down Capability

2019 ◽  
Author(s):  
Intae Moon ◽  
Mike K. Ranjram ◽  
Sombuddha Chakraborty ◽  
David J. Perreault
Keyword(s):  
High Performance ◽  
Step Down

scholarly journals The Role of Alteration of Glutamic Acid and Gaba in Learning and Memory Impairment of Rats Induced by Aluminum

2005 ◽  
Vol 3 (2) ◽  
pp. 97-101
Author(s):  
Q. Niu ◽  
P. Niu ◽  
Q. Zhang ◽  
L. Wang ◽  
S. He ◽  
...  
Keyword(s):  
Amino Acids ◽  
Cerebral Cortex ◽  
Glutamic Acid ◽  
Learning And Memory ◽  
Memory Impairment ◽  
High Performance ◽  
Gamma Aminobutyric Acid ◽  
Aluminum Exposure ◽  
Step Down

Aluminum exposure has been reported to be related to learning and memory impairment. This study examines the role of aluminum in alterating amino acids of the cerebral cortex of rats. The Step-down type tests were performed to investigate the alteration of learning and memory of rats induced by aluminum. The amino acids in the cerebral cortex were detected by high performance liquid chromatography (HLPC). Results show that the amounts of aluminum in the cerebral cortex increased by 5.0mgAl3+/(Kg·BW) group and 10.0mg Al3+/(Kg·BW) group. In the Step-down type test, the EN1 increased significantly in the Al3+ 10.0mg/(Kg·BW) group. The latency shortened obviously and the EN2 increased significantly in the 10.0mg Al3+/(Kg·BW) group. The content of Glu (Glutamic acid) increased but the content of GABA (gamma-aminobutyric acid) decreased significantly in the 10.0mg Al3+/(Kg·BW) group. This present study shows evidence that the disorder of amino acid neurotransmitters system plays an important role in the impairment of learning and memory of rats induced by aluminum.

A power step-down approach to extended high performance of ELM-free H modes in JET

1997 ◽  
Vol 37 (8) ◽  
pp. 1067-1082 ◽  
Author(s):  
F.B Marcus ◽  
B Balet ◽  
N Deliyanakis ◽  
R Giannella ◽  
C.W Gowers ◽  
...  
Keyword(s):  
High Performance ◽  
Step Down

NONISOLATED MULTIPHASE HALF-BRIDGE-BUCK TOPOLOGY WITH INHERENT CURRENT SHARING CAPABILITY AND SOFT-SWITCHING AND COUPLED-INDUCTORS CURRENT-DOUBLER

2004 ◽  
Vol 13 (03) ◽  
pp. 443-466
Author(s):  
JABER A. ABU-QAHOUQ ◽  
HONG MAO ◽  
ISSA BATARSEH
Keyword(s):  
Duty Cycle ◽  
High Performance ◽  
Dynamic Performance ◽  
Soft Switching ◽  
Coupled Inductors ◽  
Current Sharing ◽  
Highly Sensitive ◽  
High Dynamic ◽  
Step Down ◽  
Current Ripple

Point-of-load DC–DC converter requirements and design are increasingly becoming stricter than ever. This is due to the required tight dynamic tolerances allowed for supply voltages and high dynamic performance demand coupled with very high power density. Moreover, as the required converter output voltage becomes smaller, higher voltage step-down ratio is required, which results in smaller switching duty cycle in the nonisolated topologies. Step-down transformer with large turns ratio is used in the isolated topologies to step-down the voltage and keep larger duty cycle. Most of the nonisolated DC–DC topologies are buck-derived and unfortunately work at hard-switching which degrades the efficiency. DC–DC interleaved buck topologies were proposed but are highly sensitive to interleaved phases asymmetry and require high performance current sharing loop. In this paper, a nonisolated multiphase nonisolated half-bridge-buck topology is presented. This topology makes it possible to achieve soft-switching, works at larger switching duty cycle with lower output voltages, and does not require current sharing loop because of the inherent current sharing capability. Moreover, a coupled-inductor current doubler topology is also presented in this paper allowing higher step-down ratio and lower output current ripple. Theoretical analysis and experimental results are presented.

A High Performance Energy Analyzer for Use in Electron Scanning Microscopy

1969 ◽  
Vol 27 ◽  
pp. 14-15
Author(s):  
A. V. Crewe ◽  
M. Isaacson ◽  
D. Johnson
Keyword(s):  
High Performance ◽  
Vertical Plane ◽  
Median Plane ◽  
Electron Gun ◽  
Uniform Field ◽  
Loss Mechanism ◽  
Electron Scanning Microscopy ◽  
Sector Type ◽  
Double Focusing ◽  
Electron Energy Loss

A double focusing magnetic spectrometer has been constructed for use with a field emission electron gun scanning microscope in order to study the electron energy loss mechanism in thin specimens. It is of the uniform field sector type with curved pole pieces. The shape of the pole pieces is determined by requiring that all particles be focused to a point at the image slit (point 1). The resultant shape gives perfect focusing in the median plane (Fig. 1) and first order focusing in the vertical plane (Fig. 2).

Vacuum System to Minimize the Specimen Contamination of High-Performance EM

1977 ◽  
Vol 35 ◽  
pp. 68-69
Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh
Keyword(s):  
Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
High Vacuum ◽  
Vacuum System ◽  
Pump System ◽  
Pumping System ◽  
Diffusion Pump ◽  
Almost All ◽  
Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

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