http://dspace.daffodilvarsity.edu.bd:8080/handle/123456789/1477 2026-04-17T12:04:45Z 2026-04-17T12:04:45Z Taher, Md. Abu http://dspace.daffodilvarsity.edu.bd:8080/handle/20.500.11948/453 2019-05-28T09:33:02Z 2007-01-01T00:00:00Z

EFFECT OF SUBSTRATE TEMPERATURE ON THE PROPERTIES OF VACUUM EVAPORATED THIN InSb FILMS Taher, Md. Abu Indium Antimonide (InSb) thin films were deposited onto well cleaned glass substrate at different substrate temperatures (323K, 373K and 473K) by vacuum evaporation technique using InSb compound as a source material. The characteristics of the films such as composition, microstructure and electrical properties were investigated in terms of substrate temperature. Xray diffraction studies confirmed the polycrystallinity of the films and the films show preferential orientation along the (111) plane. The particle size, dislocation density and strain were evaluated. The particle size increases with the increase of substrate temperature, which was found to be in the range 14.32 to 33.35 nm. Hall measurements indicate that the films were p-type, having carrier concentration W73; 1017cm-3 and Hall mobility (0.42 - 7.10) × 103 cm2/Vs for the film thickness of 300 nm. It is observed that the carrier concentration decreases and Hall mobility increases with the increase of substrate temperature. The sheet resistance is found to decrease with the increase of substrate temperature. The Hall mobility decreased with the increase of the film thickness and the maximum Hall mobility of 1.34 × 104 cm2/Vs was obtained for the films the thickness of 1000 nm and the substrate temperature of 473K.

2007-01-01T00:00:00Z Moqsud, M. Azizul Hayashi, Shigenori Du, Yan Jun Suetsugu, Daisuke http://dspace.daffodilvarsity.edu.bd:8080/handle/20.500.11948/452 2019-05-28T09:33:02Z 2007-02-01T00:00:00Z

ASSESSMENT OF THERMAL PROPERTIES OF MUD OF THE ARIAKE SEA, JAPAN Moqsud, M. Azizul; Hayashi, Shigenori; Du, Yan Jun; Suetsugu, Daisuke Thermal environment of the mud is one of the major parts of the acid-contaminated geo-environment of the Ariake Sea. The activities of marine ecosystem both in tidal flats and inside the deep sea mud depend strongly on the thermal environment. In order to investigate the thermal properties of the Ariake sea mud, a portable thermal properties sensor and probe (KD2, Decagon Devices, Inc.) was used. Thermal conductivity, thermal resistivity, thermal diffusivity and volumetric heat capacity of the mud samples collected from both the tidal flat and inside the deep sea were measured. The thermal properties of mud collected from tidal flat showed a different trend from the mud collected from inside the sea due to the enough exposure to the sunlight and vigorous exchange of sea water in the tidal flat in different depths. Thermal conductivity of the Ariake mud was reduced 85-90% after it was oven dried and was increased up to 30% after the ignition loss test. Thermal resistivity of the Ariake mud increased dramatically after oven dried and it was less affected by the organic matter content. Thermal diffusivity was decreased 10-30% after oven dry however it was increased up to 40% after the ignition loss test. The volumetric heat capacity of the Ariake mud was reduced up to 90% and 40% after the oven dry and ignition loss, respectively.

2007-02-01T00:00:00Z Kibria, Refat Chowdhury, Md. Aminul Haque Razib, Md. Ali Ahsan http://dspace.daffodilvarsity.edu.bd:8080/handle/20.500.11948/451 2019-05-28T09:33:01Z 2007-01-01T00:00:00Z

MULTILAYER PROTECTION AND SURVIVABILITY IN WDM OPTICAL NETWORK Kibria, Refat; Chowdhury, Md. Aminul Haque; Razib, Md. Ali Ahsan Optical networks require a number of security and survivability methods as any other network does. These methods are more important for a WDM network since it carries far greater amount of data than any other network. In the multilayer networking approach, protection mechanism is more technical compared to the nonlayered network. To attain high performance and quick recovery, a well-considered coordination between different layers is mandatory. This paper provides an overview of multilayer recovery issues for WDM optical network and also focuses on how these techniques can be applied to make the next generation WDM networks more fault tolerant and survivable.

2007-01-01T00:00:00Z Saber, A. Y. Newaz, Wahed Sattar, A. K. M. Zaidi http://dspace.daffodilvarsity.edu.bd:8080/handle/20.500.11948/450 2019-05-28T09:33:01Z 2007-01-01T00:00:00Z

GENERATOR SCHEDULING (A COMBINATORIAL OPTIMIZATION PROBLEM) BY ANNEALING METHOD Saber, A. Y.; Newaz, Wahed; Sattar, A. K. M. Zaidi Generator scheduling is a combinatorial optimization problem and this paper presents a new version of annealing (SA) method to model and solve the scheduling problem. Firstly, solution is decomposed into hourly schedules and each hourly schedule is modified by decomposed-SA using bits flipping. If the generated new hourly schedule is better, by convention it is accepted deterministically. A worse hourly schedule is accepted with temperature dependent SA probability. A new solution consists of these hourly schedules of entire scheduling period after repair as unit-wise constraints may not be fulfilled at the time of individual hourly schedule modification. This helps to direct and modify schedules of appropriate hours. Secondly, this new solution is accepted for the next iteration if its cost is less than that of current solution. A higher cost new solution is accepted with temperature dependent SA probability again. Besides, problem dependent other features are incorporated to save the execution time. The proposed method is tested using the reported problem data sets. Simulation results are compared to previous reported results. Numerical results show an improvement in solution cost and time compared to the results obtained from powerful algorithms.

2007-01-01T00:00:00Z