In frared singula rities of ferion green’s function and the wilson loop

Authors:	Nguyen, Suan Huan
Keywords:	frared singula;ferion green’s function;wilson loop
Issue Date:	2002
Publisher:	H. : ĐHQGHN
Series/Report no.:	Vol. 18;No. 1 (2002)
Abstract:	Gauge-invariant, and path-dependent objects being infrared asymptotic* of a gauge-invariant ÿpinor Green fu n ctio n in the Q E D have studied. It is proved that the infrared singularities o f fe rm io n Green's function can be factorized as the Wilson loop that contains the prim a ry Path and the straight'line contour and accumulâtes all the dependence on the fo rm o f the path o f the in itial Green function.
Description:	p. 6-9
URI:	http://repository.vnu.edu.vn/handle/VNU_123/58444
ISSN:	2588-1124
Appears in Collections:	Mathematics and Physics

On the radical characteristic of regularities

Authors:	Tran, Trong Hue
Keywords:	radical characteristic;regularities
Issue Date:	2002
Publisher:	H. : ĐHQGHN
Series/Report no.:	Vol. 18;No. 1 (2002)
Description:	p. 10-15
URI:	http://repository.vnu.edu.vn/handle/VNU_123/58445
ISSN:	2588-1124
Appears in Collections:	Mathematics and Physics

Influence of intradot Coulomb interaction on transport properties of an Aharonov-Bohm interferometer

Authors:	Do, Ngoc Son Bach, Thanh Cong
Keywords:	intradot Coulomb interaction;transport properties;Aharonov-Bohm interferometer
Issue Date:	2007
Publisher:	H. : ĐHQGHN
Series/Report no.:	Vol. 23;No. 1 (2007)
Abstract:	Using Greens function method and the equation of motion approach, we have investigated the electronic transport properties of an Aharonov-Bohm (AB) ring in the presence of a magnetic field with a quantum dot inserted in one arm of the ring. In particular, we consider the electron-electron Coulomb interaction within the quantum dot. We find that the current through the system is dependent on the magnetic flux via the AB phase and the Coulomb interaction within the quantum dot, in agreement with experiments. Furthermore, the intradot Coulomb interaction induces dephasing.
Description:	p. 47-54
URI:	http://repository.vnu.edu.vn/handle/VNU_123/57487
ISSN:	2588-1124
Appears in Collections:	Mathematics and Physics

Congestion control of Wavelet image compression over wireless networks

Authors:	Ho, Anh Tuy Nguyen, Vinh An
Issue Date:	2007
Publisher:	H. : ĐHQGHN
Series/Report no.:	Vol. 23;No. 1 (2007)
Abstract:	The demand of transmission of images and video is increasing quickly recently and researchers arc trying to invest good solutions to improve the quality of these over wireless networks. There are still challenges due to the different characteristics and quality of images between wired and wireless channels. An important issue is congestion control to ensure network siability and achieve a reasonably fair distribution of the network resources among the users. The paper will present a model of congestion control by combining Wavelet image compression at the source vvith applying Fuzzy logic technique to control traffics. The simulation shows a good result, the transmission rate can be adjusted to adapt the changes of wireless channel, the buffer of intermediate devices will not be swung from idle to overflow or vice versa so that the cell loss rate is small.
Description:	p. 55-62
URI:	http://repository.vnu.edu.vn/handle/VNU_123/57489
ISSN:	2588-1124
Appears in Collections:	Mathematics and Physics

The establishment of the Vietnam atomic time scale

Authors:	Le, Van Ninh Nguyen, Bang Nguyen, Thi Hang Trieu, Viet Phuong Nguyen, Duc Trung
Keywords:	Vietnam atomic time scale;Atomic clocks;time scale algorithm
Issue Date:	2009
Publisher:	H. : ĐHQGHN
Series/Report no.:	Vol. 25;No. 2 (2009)
Abstract:	The national metrology institutes always establish their time scale UTC(k) (UTC of k laboratory) based on the atomic clocks. Atomic clocks and a time scale algorithm provides an ensemble time which is better than any component clock in the system. This paper introduces establishing of Vietnam time scale UTC(VMI) (UTC of Vietnam Metrology Institute) using the comparison data of commercial ceasium atomic clocks. We applied the time scale algorithm named AT1 and an own our method and present instrument at the time and frequency laboratory – VMI. UTC(VMI) data has appeared on the BIPM website since 2008.
Description:	p. 107-116
URI:	http://repository.vnu.edu.vn/handle/VNU_123/56794
ISSN:	2588-1124
Appears in Collections:	Mathematics and Physics