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Biswa Ranjan Nag
Biswa Ranjan Nag (1 October 1932 – 6 April 2004) was an Indian physicist and the Sisir Kumar Mitra chair professor at Rajabazar Science College, University of Calcutta. Known for his research in semiconductor physics, Nag was an elected fellow of Indian National Science Academy and Indian Academy of Sciences. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards for his contributions to Physical Sciences in 1974. Biography Born on 1 October 1932 to Sailabala and Satyaranjan Nag at Comilla, a city along the Dhaka-Chittagong Highway in the undivided Bengal of the British India (presently in Bangladesh), B. R. Nag did his graduate studies at Presidency College, Calcutta during 1949–51 and earned a master's degree in technology (M.Tech.) from the Institute of Radiophysics and Electronics (IRE) at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comilla
Comilla (; bn, কুমিল্লা, Kumillā, ), officially spelled Cumilla, is the fifth largest city of Bangladesh and second largest in Chittagong division. It is the administrative centre of the Comilla District. The name Comilla was derived from ''Komolangko'' (কমলাঙ্ক), meaning the pond of lotus. History Ancient era The Comilla region was once under ancient Samatata and was joined with Tripura State. This district came under the reign of the kings of the Harikela in the ninth century AD. Lalmai Mainamati was ruled by the Deva dynasty (eighth century AD), and (during the 10th and mid-11th century AD). In 1732, it became the centre of the Bengal-backed domain of Jagat Manikya. The Peasants' Movement against the king of Tripura in 1764, which originally formed under the leadership of Shamsher Gazi is a notable historical event in Comilla. It came under the rule of East India Company in 1765. This district was established as the Tripura district in 179 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indian Academy Of Sciences
The Indian Academy of Sciences, Bangalore was founded by Indian Physicist and Nobel Laureate C. V. Raman, and was registered as a society on 24 April 1934. Inaugurated on 31 July 1934, it began with 65 founding fellows. The first general meeting of Fellows, held on the same day, elected Raman as president, and adopted the constitution of the Academy. Objectives The aims of the Academy are to: * Promote progress in pure and applied branches of science. * Encourage important research in various branches of science. * Represent the scientific work of India internationally. * Publish work relating to scientific research initiated by the Academy, Provincial Academies, Universities and Government Scientific Institutions. * Organise meetings of Committees and Conferences to discuss papers submitted to the Academy. * Advise Government and other bodies on scientific and other matters referred to the Academy. Publications The first issue of the Academy Proceedings appeared in two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-dimensional Electron Gas
A two-dimensional electron gas (2DEG) is a scientific model in solid-state physics. It is an electron gas that is free to move in two dimensions, but tightly confined in the third. This tight confinement leads to quantized energy levels for motion in the third direction, which can then be ignored for most problems. Thus the electrons appear to be a 2D sheet embedded in a 3D world. The analogous construct of holes is called a two-dimensional hole gas (2DHG), and such systems have many useful and interesting properties. Realizations Most 2DEGs are found in transistor-like structures made from semiconductors. The most commonly encountered 2DEG is the layer of electrons found in MOSFETs (metal-oxide-semiconductor field-effect transistors). When the transistor is in inversion mode, the electrons underneath the gate oxide are confined to the semiconductor-oxide interface, and thus occupy well defined energy levels. For thin-enough potential wells and temperatures not too high, only ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microwave Radiation
Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ranges as microwaves; the above broad definition includes both UHF and EHF ( millimeter wave) bands. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz (wavelengths between 0.3 m and 3 mm). In all cases, microwaves include the entire SHF band (3 to 30 GHz, or 10 to 1 cm) at minimum. Frequencies in the microwave range are often referred to by their IEEE radar band designations: S, C, X, Ku, K, or Ka band, or by similar NATO or EU designations. The prefix ' in ''microwave'' is not meant to suggest a wavelength in the micrometer range. Rather, it indicates that microwaves are "small" (having shorter wavelengths), compared to the radio waves used prior to microwave tech ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gunn Effect
A Gunn diode, also known as a transferred electron device (TED), is a form of diode, a two-terminal semiconductor electronic component, with negative resistance, used in high-frequency electronics. It is based on the "Gunn effect" discovered in 1962 by physicist J. B. Gunn. Its largest use is in electronic oscillators to generate microwaves, in applications such as radar speed guns, microwave relay data link transmitters, and automatic door openers. Its internal construction is unlike other diodes in that it consists only of N-doped semiconductor material, whereas most diodes consist of both P and N-doped regions. It therefore conducts in both directions and cannot rectify alternating current like other diodes, which is why some sources do not use the term ''diode'' but prefer TED. In the Gunn diode, three regions exist: two of those are heavily N-doped on each terminal, with a thin layer of lightly n-doped material between. When a voltage is applied to the device, the electrical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Resistance
The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallels with mechanical friction. The SI unit of electrical resistance is the ohm (), while electrical conductance is measured in siemens (S) (formerly called the 'mho' and then represented by ). The resistance of an object depends in large part on the material it is made of. Objects made of electrical insulators like rubber tend to have very high resistance and low conductance, while objects made of electrical conductors like metals tend to have very low resistance and high conductance. This relationship is quantified by resistivity or conductivity. The nature of a material is not the only factor in resistance and conductance, however; it also depends on the size and shape of an object because these properties are extensive rather than intens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transport Phenomena
In engineering, physics, and chemistry, the study of transport phenomena concerns the exchange of mass, energy, charge, momentum and angular momentum between observed and studied systems. While it draws from fields as diverse as continuum mechanics and thermodynamics, it places a heavy emphasis on the commonalities between the topics covered. Mass, momentum, and heat transport all share a very similar mathematical framework, and the parallels between them are exploited in the study of transport phenomena to draw deep mathematical connections that often provide very useful tools in the analysis of one field that are directly derived from the others. The fundamental analysis in all three subfields of mass, heat, and momentum transfer are often grounded in the simple principle that the total sum of the quantities being studied must be conserved by the system and its environment. Thus, the different phenomena that lead to transport are each considered individually with the knowledge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it. It is relatively unreactive. Because of its high chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was first able to prepare it and characterize it in pure form. Its oxides form a family of anions known as silicates. Its melting and boiling points of 1414 °C and 3265 °C, respectively, are the second highest among all the metalloids and nonmetals, being surpassed only by boron. Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's crust. It is widely distributed in space in cosmic dusts, planetoids, and planets as various forms of silicon dioxide ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bangor, Gwynedd
Bangor (; ) is a cathedral city and community A community is a social unit (a group of living things) with commonality such as place, norms, religion, values, customs, or identity. Communities may share a sense of place situated in a given geographical area (e.g. a country, village, ... in Gwynedd, North Wales. It is the oldest city in Wales. Historic counties of Wales, Historically part of Caernarfonshire, it had a population of 18,322 in 2019, according to the Office for National Statistics. Landmarks include Bangor Cathedral, Bangor University, Garth Pier, and the Menai Suspension Bridge and Britannia Bridge which connect the city to the Anglesey, Isle of Anglesey. History The origins of the city date back to the founding of a monastic establishment on the site of Bangor Cathedral by the Celtic saint Deiniol in the early 6th century AD. itself is an old Welsh word for a wattled enclosure, such as the one that originally surrounded the cathedral site. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doctor Of Science
Doctor of Science ( la, links=no, Scientiae Doctor), usually abbreviated Sc.D., D.Sc., S.D., or D.S., is an academic research degree awarded in a number of countries throughout the world. In some countries, "Doctor of Science" is the degree used for the standard doctorate in the sciences; elsewhere the Sc.D. is a "higher doctorate" awarded in recognition of a substantial and sustained contribution to scientific knowledge beyond that required for a Doctor of Philosophy (PhD). Africa Algeria and Morocco In Algeria, Morocco, Libya and Tunisia, all universities accredited by the state award a "Doctorate" in all fields of science and humanities, equivalent to a PhD in the United Kingdom or United States. Some universities in these four Arab countries award a "Doctorate of the State" in some fields of study and science. A "Doctorate of the State" is slightly higher in esteem than a regular doctorate, and is awarded after performing additional in-depth post-doctorate research or ach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bengal
Bengal ( ; bn, বাংলা/বঙ্গ, translit=Bānglā/Bôngô, ) is a geopolitical, cultural and historical region in South Asia, specifically in the eastern part of the Indian subcontinent at the apex of the Bay of Bengal, predominantly covering present-day Bangladesh and the Indian state of West Bengal. Geographically, it consists of the Ganges-Brahmaputra delta system, the largest river delta in the world and a section of the Himalayas up to Nepal and Bhutan. Dense woodlands, including hilly rainforests, cover Bengal's northern and eastern areas, while an elevated forested plateau covers its central area; the highest point is at Sandakphu. In the littoral southwest are the Sundarbans, the world's largest mangrove forest. The region has a monsoon climate, which the Bengali calendar divides into six seasons. Bengal, then known as Gangaridai, was a leading power in ancient South Asia, with extensive trade networks forming connections to as far away as Roman Egypt. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dhaka-Chittagong Highway
The N1 or Dhaka–Chittagong Highway is a main transportation artery in Bangladesh, between Dhaka and Chittagong. Approximately in length, the road links the country's two largest cities, Dhaka and Chittagong. The highway is known along various stretches as the Chittagong–Cox's Bazar Highway and the Cox's Bazar–Teknaf Highway. Currently four lanes with a eight-lane expansion underway, the N1 is the busiest road in the country and a top development priority. Construction of a larger Dhaka-Chittagong expressway has been proposed to decrease traffic on the highway. Background When constructed, the highway was limited to two lanes of traffic for most of its length. Traffic jams or tailbacks of have been reported. In 2009, it was estimated that daily usage of the highway was 20,000–25,000 motorised vehicles, up 40% of which were trucks. The Roads and Highways Department (RHD) of the Ministry of Communication is expanding the Dhaka–Chittagong stretch to four lanes. The tar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
