DSpace Collection:http://tainguyenso.vnu.edu.vn/jspui/handle/123456789/1012026-05-19T10:09:28Z2026-05-19T10:09:28ZSome problem on the shadow of segments infinite boolean ringsTran, HuyenLe, Cao Tuhttp://tainguyenso.vnu.edu.vn/jspui/handle/123456789/10942011-04-20T08:17:45Z2007-01-01T00:00:00ZTitle: Some problem on the shadow of segments infinite boolean rings
Authors: Tran, Huyen; Le, Cao Tu
Abstract: In this paper , we consider finite Boolean rings in which were defined two orders:
natural order and antilexicographic order. The main result is concerned to the notion of shadow
of a segment. We shall prove some necessary and sufficient conditions for the shadow of a
segment to be a segment.
Description: VNU Journal of Science, Mathematics - Physics. Vol. 23 (2007), No 4, P. 221-2242007-01-01T00:00:00ZLand-vehicle mems INS/GPS positioning during GPS signal blockage periodsT., D. TanL., M.HaN., T. LongN., D. DucN., P. Thuyhttp://tainguyenso.vnu.edu.vn/jspui/handle/123456789/10902011-04-20T08:13:35Z2007-01-01T00:00:00ZTitle: Land-vehicle mems INS/GPS positioning during GPS signal blockage periods
Authors: T., D. Tan; L., M.Ha; N., T. Long; N., D. Duc; N., P. Thuy
Abstract: The demand of vehicle navigation and guidance has been urgent for many years. The
idea of integrating multisensor navigation systems was implemented. The most efficient
multisensor configuration is the system integrating an inertial navigation system (INS) consisting
of MEMS based micro sensors and a global positioning system (GPS). In such system, the GPS is
used for providing position and velocity whereas the INS for providing orientation. The estimation
of the system errors is performed by a Kalman filter (KF). A serious problem occurs in the
INS/GPS system application that is caused by the accidental GPS signal blockages. In this paper,
the main objective is to improve the accuracy of the obtained navigation parameters during periods
of GPS signal outages using different methods. The overall performance of the system have been
analyzed by experimentation data; and results show that these methods indeed improve the quality
of the navigation and guidance systems.
Description: VNU Journal of Science, Mathematics - Physics. Vol. 23 (2007), No 4, P. 243-2512007-01-01T00:00:00ZInvestigation of the embedded fiber bragg grating temperature sensorTran, Thi TamDang, Quoc TrungTran, Anh VuLe, Huu MinhDo, Ngoc Chunghttp://tainguyenso.vnu.edu.vn/jspui/handle/123456789/10862011-04-20T08:09:17Z2007-01-01T00:00:00ZTitle: Investigation of the embedded fiber bragg grating temperature sensor
Authors: Tran, Thi Tam; Dang, Quoc Trung; Tran, Anh Vu; Le, Huu Minh; Do, Ngoc Chung
Abstract: An embedded fiber Bragg grating (FBG) sensor, which fabricated in IMS, for
temperature sensing was proposed. The temperature responses of the in-fiber Bragg gratings
(FBGs) have been investigated. It was found that these responses ranged from 10.6 pm/°C to 12.0
pm/°C. The temperature sensitivity of the FBGs was 0.2°C. The strain responses remained
temperature independent over a temperature range of 20 – 180 C. The results obtained are in
agreement, within the experimental error, with predictions based on material parameters. Although
the temperature response is nonlinear over the temperature range 20 °C to 180 °C, in practical
systems the temperature response of the sensor may be assumed to be linear within the
temperature range 20 °C to 80 °C.
Description: VNU Journal of Science, Mathematics - Physics. Vol. 23 (2007), No 4, P. 237-2422007-01-01T00:00:00ZPreparation and characteristics of LiF:Mg,Cu,Na,Si thermoluminescent materialVu, Thi Thai HaNguyen, Thi Quy HaiNguyen, Ngoc LongLe, Van Vuhttp://tainguyenso.vnu.edu.vn/jspui/handle/123456789/10672011-04-20T07:42:40Z2007-01-01T00:00:00ZTitle: Preparation and characteristics of LiF:Mg,Cu,Na,Si thermoluminescent material
Authors: Vu, Thi Thai Ha; Nguyen, Thi Quy Hai; Nguyen, Ngoc Long; Le, Van Vu
Abstract: Lithium fluoride (LiF) thermoluminescent powder doped with Mg, Cu, Na, and Si
as activators was prepared. X-ray diffraction analysis indicated that doping LiF with different
activators makes crystal lattice somewhat expand. The dosimetric properties of the powder were
studied. The main dosimetric peak of LiF:Mg,Cu,Na,Si appeared in the range of 227−247oC and
the ratio of the height of the main peak to that of the other small peaks in the LiF:Mg,Cu,Na,Si
is much greater than that in the LiF:Mg,Ti and LiF:Mg,Cu,P. The preparation conditions such
as annealing temperature and duration, annealing atmosphere, doping with different activators
etc. were investigated.
Description: VNU Journal of Science, Mathematics - Physics. Vol. 23 (2007), No 4, P. 225-2312007-01-01T00:00:00Z