A WRITEUP ON SUPERCONDUCTIVITY

Superconductivity is a phenomenon occurring in certain materials at very low temperatures, characterized by exactly zero electrical resistance and the exclusion of the interior magnetic field (this is known as Meissner effect).
The electrical resistivity of a metallic conductor decreases gradually as the temperature is lowered. However, in ordinary conductors such as copper and silver, impurities and other defects impose a lower limit. Even near absolute zero a real sample of copper shows a non-zero resistance. The resistance of a superconductor, on the other hand, drops abruptly to zero when the material is cooled below its "critical temperature". An electric current flowing in a loop of superconducting wire can persist indefinitely with no power source. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon. It cannot be understood simply as the idealization of "perfect conductivity" in classical physics.
Superconductivity occurs in a wide variety of materials, including simple elements like tin and aluminium, various metallic alloys and some heavily-doped semiconductors. Superconductivity does not occur in noble metals like gold and silver, nor in most ferromagnetic metals.
In 1986 the discovery of a family of cuprate-perovskite ceramic materials known as high-temperature superconductors, with critical temperatures in excess of 90 Kelvin, spurred renewed interest and research in superconductivity for several reasons. As a topic of pure research, these materials represented a new phenomenon not explained by the current theory. And, because the superconducting state persists up to more manageable temperatures, past the economically-important boiling point of liquid nitrogen (77 Kelvin), more commercial applications are feasible, especially if materials with even higher critical temperatures could be discovered.
Elementary properties of superconductors
Most of the physical properties of superconductors vary from material to material, such as the heat capacity and the critical temperature, critical field, and critical current density at which superconductivity is destroyed.
On the other hand, there is a class of properties that are independent of the underlying material. For instance, all superconductors have exactly zero resistivity to low applied currents when there is no magnetic field present. The existence of these "universal" properties implies that superconductivity is a thermodynamic phase, and thus possess certain distinguishing properties which are largely independent of microscopic details.
Theories of superconductivity
Since the discovery of superconductivity, great efforts have been devoted to finding out how and why it works. During the 1950s, theoretical condensed matter physicists arrived at a solid understanding of "conventional" superconductivity, through a pair of remarkable and important theories: the phenomenological Ginzburg-Landau theory (1950) and the microscopic BCS theory (1957). Generalizations of these theories form the basis for understanding the closely related phenomenon of superfluidity, because they fall into the Lambda transition universality class, but the extent to which similar generalizations can be applied to unconventional superconductors as well is still controversial. The four-dimensional extension of the Ginzburg-Landau theory, the Coleman-Weinberg model, is important in quantum field theory and cosmology.

Classification
There is not just one criterion to classify superconductors. The most common are:
By their physical properties: they can be Type I (if their phase transition is of first order) or Type II (if their phase transition is of second order).
By the theory to explain them: they can be conventional (if they are explained by the BCS theory or its derivates) or unconventional (if not).
By their critical temperature: they can be high temperature (generally considered if they reach the superconducting state just cooling them with liquid nitrogen, that is, if Tc > 77K), or low temperature (generally if they need other techniques to be cooled under their critical temperature).
By material: they can be chemical elements (as mercury or lead), alloys (as niobium-titanium or germanium-niobium), ceramics (as YBCO or the magnesium diboride), or organic superconductors (as fullerens or carbon nanotubes, which technically might be included between the chemical elements as they are made of carbon).

Applications
[1] Superconducting magnets are some of the most powerful electromagnets known. They are used in maglev trains, MRI and NMR machines and the beam-steering magnets used in particle accelerators.
[2] They can also be used for magnetic separation, where weakly magnetic particles are extracted from a background of less or non-magnetic particles, as in the pigment industries.
[3]Superconductors have also been used to make digital circuits (e.g. based on the Rapid Single Flux Quantum technology) and RF and microwave filters for mobile phone base stations.
[4] Superconductors are used to build Josephson junctions which are the building blocks of SQUIDs (superconducting quantum interference devices), the most sensitive magnetometers known. Series of Josephson devices are used to define the SI volt. Depending on the particular mode of operation, a Josephson junction can be used as photon detector or as mixer. The large resistance change at the transition from the normal- to the superconducting state is used to build thermometers in cryogenic micro-calorimeter photon detectors.
[5] Other early markets are arising where the relative efficiency, size and weight advantages of devices based on HTS outweigh the additional costs involved.
[6] Promising future applications include high-performance transformers, power storage devices, electric power transmission, electric motors (e.g. for vehicle propulsion, as in vactrains or maglev trains), magnetic levitation devices, and Fault Current Limiters.
However superconductivity is sensitive to moving magnetic fields so applications that use alternating current (e.g. transformers) will be more difficult to develop than those that rely upon direct current.

MORE REQUESTS HAVE BEEN PROCESSED

As per the further requests from dear visitors on the blog, We are publishing marksheets as follows:
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Roll No. : 116969
Name : RAMAN GARG
RANK -375
Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 103
General Studies (Paper-IV) 300 168
General Studies(Paper-V) 300 155
Optional I,Zoology Paper-VI 300 157
Paper-VII 300 176
Optional II, Medical Science Paper-VIII 300 160
Paper-IX 300 154
Penalty Marks 0
Written Total 2000 1073
Interview Marks 300 165
Final Total 2300 1238
Remarks : Recommended.

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Roll No. : 6433
Name : E VISHNU VARDHAN REDDY
RANK-87
Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 116
General Studies (Paper-IV) 300 208
General Studies(Paper-V) 300 164
Optional I,Public Administration Paper-VI 300 158
Paper-VII 300 147
Optional II, Medical Science Paper-VIII 300 163
Paper-IX 300 182
Penalty Marks 0
Written Total 2000 1138
Interview Marks 300 165
Final Total 2300 1303
Remarks : Recommended.

MARK SHEETS AS REQUESTED BY ONE READER

As per the message sent by Mr Sahil Khurana...I am posting the mark sheets of the following persons.
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Roll No. : 4727--------------
Name : AMANJEET KAUR
RANK-365

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 121
General Studies (Paper-IV) 300 172
General Studies(Paper-V) 300 167
Optional I,Economics Paper-VI 300 193
Paper-VII 300 181
Optional II, Sociology Paper-VIII 300 144
Paper-IX 300 108
Penalty Marks 0
Written Total 2000 1086
Interview Marks 300 155
Final Total 2300 1241
Remarks : Recommended.
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Roll No. : 5618--------------
Name : A ANTO ALPHONSE
RANK 42

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 150
General Studies (Paper-IV) 300 164
General Studies(Paper-V) 300 110
Optional I,Geography Paper-VI 300 178
Paper-VII 300 184
Optional II, History Paper-VIII 300 169
Paper-IX 300 173
Penalty Marks 0
Written Total 2000 1128
Interview Marks 300 204
Final Total 2300 1332
Remarks : Recommended.

UPSC 2007 MARKS ARE OUT

UPSC has finally declared marks for civil services exam 2007. For some people it is a big surprise and for few it is a moment of heart broken.Luckily I got satisfactory marks except for one optional where I got a bit less than 300 marks. otherwise in general studies i got more then 300 and in other optional i got very high i.e. more than 350 marks.In interview my marks are not satisfactory. Any way this time merit list is very high.Last general candidate is at 1221. I wish a very good luck for those who have not done well this time.Don't loose hope..keep trying....We are going to upload marks of few of the finally selected aspirants selected randomly on this blog.You can have an idea about the overall marks afterwords.
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Roll No. : 14954--------------------------
Name : TAFSEER IQUBAL

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 119
General Studies (Paper-IV) 300 212
General Studies(Paper-V) 300 108
Optional I,History Paper-VI 300 142
Paper-VII 300 124
Optional II, Public Administration Paper-VIII 300 169
Paper-IX 300 192
Penalty Marks 0
Written Total 2000 1066
Interview Marks 300 210
Final Total 2300 1276
Remarks : Recommended.
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Roll No. : 1434--------------------------
Name : ASHIMA JAIN

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 090
General Studies (Paper-IV) 300 174
General Studies(Paper-V) 300 203
Optional I,Economics Paper-VI 300 172
Paper-VII 300 187
Optional II, Psychology Paper-VIII 300 181
Paper-IX 300 175
Penalty Marks 0
Written Total 2000 1182
Interview Marks 300 204
Final Total 2300 1386
Remarks : Recommended.
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Roll No. : 40546--------------------------
Name : ASHISH SINGH

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 116
General Studies (Paper-IV) 300 177
General Studies(Paper-V) 300 128
Optional I,Psychology Paper-VI 300 152
Paper-VII 300 161
Optional II, Public Administration Paper-VIII 300 166
Paper-IX 300 157
Penalty Marks 0
Written Total 2000 1057
Interview Marks 300 132
Final Total 2300 1189
Remarks : Not Recommended.

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Roll No. : 7778--------------------------
Name : CHHAVI BHARDWAJ

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 140
General Studies (Paper-IV) 300 211
General Studies(Paper-V) 300 175
Optional I,Psychology Paper-VI 300 148
Paper-VII 300 158
Optional II, Public Administration Paper-VIII 300 163
Paper-IX 300 169
Penalty Marks 0
Written Total 2000 1164
Interview Marks 300 216
Final Total 2300 1380
Remarks : Recommended.

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Roll No. : 7451--------------------------
Name : DEVESH GUPTA

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 105
General Studies (Paper-IV) 300 182
General Studies(Paper-V) 300 153
Optional I,Geography Paper-VI 300 140
Paper-VII 300 177
Optional II, Public Administration Paper-VIII 300 175
Paper-IX 300 186
Penalty Marks 0
Written Total 2000 1118
Interview Marks 300 120
Final Total 2300 1238
Remarks : Recommended.
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Roll No. : 96359--------------------------
Name : KHUSHBOO GOEL

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 130
General Studies (Paper-IV) 300 192
General Studies(Paper-V) 300 163
Optional I,Commerce & Accountancy Paper-VI 300 162
Paper-VII 300 169
Optional II, Public Administration Paper-VIII 300 172
Paper-IX 300 168
Penalty Marks 0
Written Total 2000 1156
Interview Marks 300 225
Final Total 2300 1381
Remarks : Recommended.
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Roll No. : 126165--------------------------
Name : KINJAL SINGH

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 125
General Studies (Paper-IV) 300 184
General Studies(Paper-V) 300 156
Optional I,Law Paper-VI 300 177
Paper-VII 300 185
Optional II, Philosophy Paper-VIII 300 167
Paper-IX 300 161
Penalty Marks 0
Written Total 2000 1155
Interview Marks 300 195
Final Total 2300 1350
Remarks : Recommended.

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Roll No. : 3846--------------------------
Name : NAND KUMARUM

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 120
General Studies (Paper-IV) 300 182
General Studies(Paper-V) 300 208
Optional I,Geography Paper-VI 300 166
Paper-VII 300 177
Optional II, Psychology Paper-VIII 300 195
Paper-IX 300 157
Penalty Marks 0
Written Total 2000 1205
Interview Marks 300 180
Final Total 2300 1385
Remarks : Recommended.
*********************************************88
Roll No. : 6431--------------------------
Name : NIRAJ KUMAR

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 119
General Studies (Paper-IV) 300 170
General Studies(Paper-V) 300 136
Optional I,Geography Paper-VI 300 137
Paper-VII 300 157
Optional II, Psychology Paper-VIII 300 186
Paper-IX 300 172
Penalty Marks 0
Written Total 2000 1077
Interview Marks 300 120
Final Total 2300 1197
Remarks : Recommended.

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Roll No. : 7524--------------------------
Name : RAJIV SHANKAR

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 130
General Studies (Paper-IV) 300 206
General Studies(Paper-V) 300 156
Optional I,Psychology Paper-VI 300 140
Paper-VII 300 138
Optional II, Public Administration Paper-VIII 300 140
Paper-IX 300 161
Penalty Marks 0
Written Total 2000 1071
Interview Marks 300 160
Final Total 2300 1231
Remarks : Recommended.

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Roll No. : 29222--------------------------
Name : RAM SINGH

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 124
General Studies (Paper-IV) 300 204
General Studies(Paper-V) 300 155
Optional I,Geography Paper-VI 300 145
Paper-VII 300 165
Optional II, Public Administration Paper-VIII 300 151
Paper-IX 300 173
Penalty Marks 0
Written Total 2000 1117
Interview Marks 300 195
Final Total 2300 1312
Remarks : Recommended.

****************************************88
Roll No. : 154897--------------------------
Name : ADAPA KARTHIK

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 103
General Studies (Paper-IV) 300 194
General Studies(Paper-V) 300 185
Optional I,Psychology Paper-VI 300 193
Paper-VII 300 155
Optional II, Zoology Paper-VIII 300 203
Paper-IX 300 203
Penalty Marks 0
Written Total 2000 1236
Interview Marks 300 222
Final Total 2300 1458
Remarks : Recommended.

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Roll No. : 18905--------------------------
Name : SUPREET SINGH GULATI

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 104
General Studies (Paper-IV) 300 203
General Studies(Paper-V) 300 160
Optional I,Electrical Engineering Paper-VI 300 186
Paper-VII 300 166
Optional II, Physics Paper-VIII 300 208
Paper-IX 300 170
Penalty Marks 0
Written Total 2000 1197
Interview Marks 300 216
Final Total 2300 1413
Remarks : Recommended.

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Roll No. : 5999--------------------------
Name : SATYANJAL PANDEY

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 148
General Studies (Paper-IV) 300 173
General Studies(Paper-V) 300 136
Optional I,Public Administration Paper-VI 300 147
Paper-VII 300 133
Optional II, Medical Science Paper-VIII 300 149
Paper-IX 300 125
Penalty Marks 0
Written Total 2000 1011
Interview Marks 300 210
Final Total 2300 1221
Remarks : Recommended.
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Roll No. : 15860--------------------------
Name : RASHMI MISHRA

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 116
General Studies (Paper-IV) 300 201
General Studies(Paper-V) 300 164
Optional I,Geography Paper-VI 300 178
Paper-VII 300 168
Optional II, History Paper-VIII 300 175
Paper-IX 300 175
Penalty Marks 0
Written Total 2000 1177
Interview Marks 300 069
Final Total 2300 1246
Remarks : Recommended.

******************************Roll No. : 84559--------------------------
Name : SMITA SINGH

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 136
General Studies (Paper-IV) 300 167
General Studies(Paper-V) 300 176
Optional I,Anthropology Paper-VI 300 147
Paper-VII 300 164
Optional II, Public Administration Paper-VIII 300 154
Paper-IX 300 167
Penalty Marks 0
Written Total 2000 1111
Interview Marks 300 165
Final Total 2300 1276
Remarks : Recommended.
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Roll No. : 28420--------------------------
Name : SONAL GOEL

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 116
General Studies (Paper-IV) 300 210
General Studies(Paper-V) 300 195
Optional I,Commerce & Accountancy Paper-VI 300 147
Paper-VII 300 165
Optional II, Public Administration Paper-VIII 300 166
Paper-IX 300 190
Penalty Marks 0
Written Total 2000 1189
Interview Marks 300 183
Final Total 2300 1372
Remarks : Recommended.
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Roll No. : 2608
Name : RAGHAVENDRA PAL SINGH

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 103
General Studies (Paper-IV) 300 176
General Studies(Paper-V) 300 180
Optional I,Geography Paper-VI 300 119
Paper-VII 300 172
Optional II, Public Administration Paper-VIII 300 167
Paper-IX 300 193
Penalty Marks 0
Written Total 2000 1110
Interview Marks 300 135
Final Total 2300 1245
Remarks : Recommended.
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Roll No. : 168908--------------------------
Name : BEER SINGH

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 111
General Studies (Paper-IV) 300 159
General Studies(Paper-V) 300 161
Optional I,Geography Paper-VI 300 161
Paper-VII 300 186
Optional II, Sociology Paper-VIII 300 135
Paper-IX 300 168
Penalty Marks 0
Written Total 2000 1081
Interview Marks 300 135
Final Total 2300 1216
Remarks : Recommended.

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Roll No. : 3211--------------------------
Name : VIVEK YADAV

Civil Services(Main) Examination 2007
Subject Maximum
Marks Marks
Obtained
Essay(Paper III) 200 128
General Studies (Paper-IV) 300 157
General Studies(Paper-V) 300 192
Optional I,Geography Paper-VI 300 153
Paper-VII 300 180
Optional II, Psychology Paper-VIII 300 155
Paper-IX 300 200
Penalty Marks 0
Written Total 2000 1165
Interview Marks 300 180
Final Total 2300 1345
Remarks : Recommended