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Sunday, May 8, 2011

New Material Derived From Graphene May Have Many Applications In Future Electronics

Sulekha Rani.R, P.G.T Chemistry,KV NTPC Kayamkulam

(Graphane crystal. This novel two-dimensional material is obtained from graphene (a monolayer of carbon atoms) by attaching hydrogen atoms (red) to each carbon atoms (blue) in the crystal. (Credit: Image courtesy of University of Manchester)

— Researchers at The University of Manchester have produced a ground-breaking new material, graphane, which has been derived from graphene.


Graphene, which was discovered at the University in 2004, is a one-atom-thick crystal with unusual highly conductive properties, which has quickly become one of the hottest topics in physics and materials science. It is also tipped for a number of future applications in electronics and photonics.

But research published January, 30, 2009 by Professor Andre Geim and Dr Kostya Novoselov, who led the group that discovered graphene in 2004, suggests its uses could be far greater.

That's because the scientists, from the University’s School of Physics and Astronomy, have found that graphene will react with other substances to form new compounds with different properties - opening up further opportunities for development in the field of electronics.

As part of the research, published in the journal Science, Professor Geim and Dr Novoselov have used hydrogen to modify highly conductive graphene into a new two-dimensional crystal - graphane.

The addition of a hydrogen atom on each of the carbon atoms in the graphene achieved the new material without altering or damaging the distinctive one-atom-thick ‘chicken wire’ construction itself.

But instead of being highly conductive, like graphene, the new substance graphane has insulating properties.

The researchers say the findings demonstrate that the material can be modified using chemistry - clearing the way for the discovery of further graphene-based chemical derivatives.

“Graphene is an excellent conductor and is tipped for many electronic applications,” said Dr Novoselov. “However it was tempting to look at ways to gain additional control of its electronic properties through the use of chemistry.

“Our work proves that this is a viable route and hopefully will open the floodgates for other graphene-based chemical derivatives. This should widen the possible applications dramatically.”

The unique electronic properties of graphene have already led researchers to look at ways the material could be used in the development of increasingly small and fast transistors. However, the absence of the energy gap in the electronic spectra forced scientists to use rather complex graphene-based structures like quantum point contacts and quantum dots for this purpose.

The discovery that graphene can be modified into new materials, fine tuning its electronic properties, has opened up the increasingly rich possibilities in the development of future electronic devices from this truly versatile material.

Professor Geim said: “The modern semiconductor industry makes use of the whole period table: from insulators to semiconductors to metals.

“But what if a single material is modified so that it covers the entire spectrum needed for electronic applications?

“Imagine a graphene wafer with all interconnects made from highly conductive, pristine graphene whereas other parts are modified chemically to become semiconductors and work as transistors.”

The Manchester researchers produced high-quality crystals of graphane by exposing pristine graphene to atomic hydrogen. The approach shows a way of making many other ultra-thin crystalline materials based on graphene



Scientists Strive to Replace Silicon With Graphene on Nanocircuitry


Sulekha Rani.R , P.G T Chemistry, K V NTPC kayamkulam

(In a technique known as thermochemical nanolithography, the tip of an atomic force microscope uses heat to turn graphene oxide into reduced graphene oxide, a substance that can be used to produce nanocircuits and nanowires with controllable conductivity. (Credit: University of Illinois at Urbana-Champaign)


Scientists have made a breakthrough toward creating nanocircuitry on graphene, widely regarded as the most promising candidate to replace silicon as the building block of transistors. They have devised a simple and quick one-step process based on thermochemical nanolithography (TCNL) for creating nanowires, tuning the electronic properties of reduced graphene oxide on the nanoscale and thereby allowing it to switch from being an insulating material to a conducting material.


The technique works with multiple forms of graphene and is poised to become an important finding for the development of graphene electronics. The research appears in the June 11, 2010, issue of the journal Science.


Scientists who work with nanocircuits are enthusiastic about graphene because electrons meet with less resistance when they travel along graphene compared to silicon and because today's silicon transistors are nearly as small as allowed by the laws of physics. Graphene also has the edge due to its thickness -- it's a carbon sheet that is a single atom thick. While graphene nanoelectronics could be faster and consume less power than silicon, no one knew how to produce graphene nanostructures on such a reproducible or scalable method. That is until now.


"We've shown that by locally heating insulating graphene oxide, both the flakes and epitaxial varieties, with an atomic force microscope tip, we can write nanowires with dimensions down to 12 nanometers. And we can tune their electronic properties to be up to four orders of magnitude more conductive. We've seen no sign of tip wear or sample tearing," said Elisa Riedo, associate professor in the School of Physics at the Georgia Institute of Technology.

On the macroscale, the conductivity of graphene oxide can be changed from an insulating material to a more conductive graphene-like material using large furnaces.

Now, the research team used TCNL to increase the temperature of reduced graphene oxide at the nanoscale, so they can draw graphene-like nanocircuits. They found that when it reached 130 degrees Celsius, the reduced graphene oxide began to become more conductive.


"So the beauty of this is that we've devised a simple, robust and reproducible technique that enables us to change an insulating sample into a conducting nanowire. These properties are the hallmark of a productive technology," said Paul Sheehan, head of the Surface Nanoscience and Sensor Technology Section at the Naval Research Laboratory in Washington, D.C.

The research team tested two types of graphene oxide -- one made from silicon carbide, the other with graphite powder.


"I think there are three things about this study that make it stand out," said William P. King, associate professor in the Mechanical Science and Engineering department at the University of Illinois at Urbana-Champaign. "First, is that the entire process happens in one step. You go from insulating graphene oxide to a functional electronic material by simply applying a nano-heater. Second, we think that any type of graphene will behave this way. Third, the writing is an extremely fast technique. These nanostructures can be synthesized at such a high rate that the approach could be very useful for engineers who want to make nanocircuits."


"This project is an excellent example of the new technologies that epitaxial graphene electronics enables," said Walt de Heer, Regent's Professor in Georgia Tech's School of Physics and the original proponent of epitaxial graphene in electronics. His study led to the establishment of the Materials Research Science and Engineering Center two years ago. "The simple conversion from graphene oxide to graphene is an important and fast method to produce conducting wires. This method can be used not only for flexible electronics, but it is possible, sometime in the future, that the bio-compatible graphene wires can be used to measure electrical signals from single biological cells."










Friday, May 6, 2011

An inspirational speech BY APJ

Why are we
in India
so embarrassed to recognize our own strengths, our achievements?

We are such a great nation. We have so many amazing success stories but we
refuse to acknowledge them. Why?

We are the first in milk production.

We are number one in Remote sensing satellites.

We are the second largest producer of wheat.

We are the second largest producer of rice.

Look at Dr. Sudarshan , he has transferred the tribal village into a
self-sustaining, self-driving unit. There are millions of such achievements but
our media is only obsessed in the bad news and failures and disasters.

I was in Tel Aviv once and I was reading the Israeli newspaper. It was the day
after a lot of attacks and bombardments and deaths had taken place. The Hamas
had struck. But the front page of the newspaper had the picture of a Jewish
gentleman who in five years had transformed his desert into an orchid and a
granary. It was this inspiring picture that everyone woke up to. The gory
details of killings, bombardments, deaths, were inside in the newspaper, buried
among other news.

In India we only read about death,
sickness, terrorism, crime.. Why are we so NEGATIVE? Another question: Why are
we, as a nation so obsessed with foreign things? We want foreign T.Vs, we want
foreign shirts. We want foreign technology.


Why this obsession with
everything imported. Do we not realize that self-respect comes with
self-reliance? I was in
Hyderabad
giving this lecture, when a 14 year old girl asked me for my autograph. I asked
her what her goal in life is. She replied: I want to live in a developed
India
. For her, you and I will have to build this developed
India . You must proclaim. India
is not an under-developed nation; it is a highly developed nation.


YOU say that
our government is inefficient.

YOU say that our laws are too old.

YOU say that the municipality does not pick up the garbage.

YOU say that the phones don't work, the railways are a joke. The airline is the
worst in the world, mails never reach their destination.

YOU say that our country has been fed to the dogs and is the absolute pits.


YOU say, say and say. What do
YOU do about it?


Take a person on his way to Singapore.
Give him a name - 'YOURS'. Give him a face - 'YOURS'. YOU walk out of the
airport and you are at your International best. In
Singapore you don't throw cigarette
butts on the roads or eat in the stores. YOU are as proud of their Underground
links as they are. You pay $5 (approx. Rs. 60) to drive through Orchard Road
(equivalent of Mahim Causeway or Pedder Road) between 5 PM and 8 PM. YOU come
back to the parking lot to punch your parking ticket if you have over stayed in
a restaurant or a shopping mall irrespective of your status identity In
Singapore
you don't say anything, DO YOU? YOU wouldn't dare to eat in public during
Ramadan, in
Dubai
. YOU would not dare to go out without your head covered in Jeddah.

YOU would not dare to buy an employee of the telephone exchange in London at 10
pounds (Rs.650) a month to, 'see to it that my STD and ISD calls are billed to
someone else.'YOU would not dare to speed beyond 55 mph (88 km/h) in Washington
and then tell the traffic cop, 'Jaanta hai main kaun hoon (Do you know who I
am?). I am so and so's son. Take your two bucks and get lost.' YOU wouldn't
chuck an empty coconut shell anywhere other than the garbage pail on the beaches
in
Australia and New Zealand
.

Why don't YOU spit Paan on the streets of
Tokyo?
Why don't YOU use examination jockeys or buy fake certificates in
Boston??? We are still
talking of the same YOU. YOU who can respect and conform to a foreign system in
other countries but cannot in your own. You who will throw papers and
cigarettes on the road the moment you touch Indian ground. If you can be an
involved and appreciative citizen in an alien country, why cannot you be the
same here in
India?

In an interview, the famous
Ex-municipal commissioner of
Bombay,
Mr. Tinaikar, had a point to make. 'Rich people's dogs are walked on the
streets to leave their affluent droppings all over the place,' he said. 'And
then the same people turn around to criticize and blame the authorities for
inefficiency and dirty pavements. What do they expect the officers to do? Go
down with a broom every time their dog feels the pressure in his bowels?

In
America
every dog owner has to clean up after his pet has done the job. Same in
Japan.

Will the Indian citizen do that here?' He's right. We go to the polls to choose
a government and after that forfeit all responsibility.

We sit back wanting to be pampered and expect the government to do everything
for us whilst our contribution is totally negative. We expect the government to
clean up but we are not going to stop chucking garbage all over the place nor
are we going to stop to pick a up a stray piece of paper and throw it in the
bin. We expect the railways to provide clean bathrooms but we are not going to
learn the proper use of bathrooms.

We want Indian Airlines and Air
India
to provide the best of food and toiletries but we are not going to stop
pilfering at the least opportunity.

This applies even to the staff who is known not to pass on the service to the
public.



When it comes to burning social
issues like those related to women, dowry, girl child! and others, we make loud
drawing room protestations and continue to do the reverse at home. Our excuse?
'It's the whole system which has to change, how will it matter if I alone
forego my sons' rights to a dowry.' So who's going to change the system?

What does a system consist of? Very conveniently for us it consists of our
neighbours, other households, other cities, other communities and the
government. But definitely not me and YOU. When it comes to us actually making
a positive contribution to the system we lock ourselves along with our families
into a safe cocoon and look into the distance at countries far away and wait
for a Mr.Clean to come along & work miracles for us with a majestic sweep
of his hand or we leave the country and run away.

Like lazy cowards hounded by our fears we run to
America to bask in their glory and
praise their system. When
New York becomes
insecure we run to
England
. When
England
experiences unemployment, we take the next flight out to the Gulf. When the
Gulf is war struck, we demand to be rescued and brought home by the Indian
government. Everybody is out to abuse and rape the country. Nobody thinks of
feeding the system. Our conscience is mortgaged to money.



Dear Indians, The article is
highly thought inductive, calls for a great deal of introspection and pricks
one's conscience too . I am echoing J. F. Kennedy's words to his fellow
Americans to relate to Indians ..


'ASK WHAT WE CAN DO FOR INDIA AND DO WHAT HAS TO BE DONE TO MAKE INDIA WHAT AMERICA AND OTHER WESTERN COUNTRIES
ARE TODAY'


Lets do what India
needs from us.


Jai Hind




Tuesday, May 3, 2011

DYNAMIC INSTITUTION


1. An educational Institution that radiates greatness by teaching capacity of the teachers.

2. An educational Institution is great because creativity is bubbling everywhere.

3. An educational Institution is great, because it cherishes the learning environment with library, internet, e-learning and creative laboratories.

4. An educational Institution is great, because it creates and generate students with confidence that “I can do it” that in-turn will generate the team spirit that “We will do it” and “India will do it”.

5. An educational Institution is great because it has teachers who lead a unique way of life with purity and become role models for the students and develop them as enlightened citizens.

6. An educational Institution is great because it has the capacity to teach all students to succeed.

7. An educational Institution that generates creativity among all students irrespective of whether they belong to arts or science stream.

8. An educational Institution is great, that generates alumni who cherish that they belong to this Institution.

Some Great thoughts

1 I will bring a change in the life of 100 women in education, employment or healthcare.
2 I will promote among women courage and self reliance in every walk of their life.
3 I will work continuously to remove dowry, girl child feticide and crime against women and children.
4 I will promote among citizens, righteousness in the heart that will blossom into beauty in the character.
5 I will light the lamp of knowledge in the nation and ensure that it remains lit for ever.
6 I will work with integrity and succeed with integrity.

Teachers









When I see the future teachers in this audience, I look at you dear friends, as one integrated system of education, system of learning and system of knowledge. You have to provide the guidance and build capacity among the youth to participate in the realization of distinctive profile I have mentioned above.
The seeds of peace in the world have their origin in the righteousness in the heart of every individual. Such righteous citizens lead to the evolution of enlightened society. Education with value system has to be so designed that the righteousness in the heart is developed in young minds. That should be the mission of education. The prime learning environment is five to seventeen years of age for over 25,000 hours. This reminds me of an ancient Greek teacher's saying, "Give me a child for seven years; afterwards, let God or devil take the child. They cannot change the child". This indicates the power of great teachers and teacher of teachers. True education is the acquisition of enlightened feelings and enlightened powers to understand daily events and to understand the permanent truth by linking citizen, to his environment, human and planetary. I would like to quote from the great philosopher Dr. S. Radhakrishnan particularly for the benefit of students and teachers - “The sense of human need is there and the teacher can satisfy it by giving to the youth an idea of the fundamental power and worth of man, his spiritual dignity as man, a supra-national culture and an all embracing humanity.” This can be achieved only by a teacher who loves teaching.

Wednesday, April 20, 2011

Saluting ISRO scientists for the successful launch of PSLV C16






ISRO has today successfully launched PSLV C 16. They have also placed three satellites, including Resourcesat-2 in the orbit. This is the 18th launch of PSLV with 16 uninterrupted success.

Those who had watched live the launch of PSLV today morning, would not have missed the tense and delightful 18 minutes, till the launch was declared successful, after placing the three satellites in the respective orbits. I could see the tension on the face of the scientists. I saw few of them praying with folded hands. It may be recalled that in 2010, ISRO's launch of GSLV satellite was not successful and the satellite went into bay of Bengal. Probably, the entire Nation joined them with prayers for the success.

In this Mission, they have also sent three high resolution cameras for taking pictures. First set of pictures will be received by the control authorities from the satellite from 28th April.

Today's event is a historical event in Indian Space Mission. India has positioned herself as the leader in 'Remote Sensing'. India will be supplying important data to various countries in future.

It was quite heartening to see Dr Radhakrishnan, Chairman of ISRO introducing all his team leaders and asking them to speak for few minutes to the Nation through live telecast. That proved the good leadership and team spirit of ISRO.

Dr Radhakrishnan assured the Nation today that they will be launching PSLV C-17 and C-18 shortly.

ISRO scientists have made India and all the citizens proud. Let us pray for their future success too. It is a much bigger a victory for India than the Word Cup. At least in future, let us hope such scientific achievements and global positioning of India will receive deserved media attention.

The PSLV-C16 rocket launched by Indian Space Research Organisation (ISRO) from Sriharikota on Wednesday successfully injected India’s latest remote sensing spacecraft Resourcesat-2 and two smaller satellites into the Earth’s orbit.

Within minutes of its launch at around 10.30 am, the PSLV-C16 on its 18th mission put India’s latest remote sensing spacecraft along with two other satellites into the orbit.

The launch drew more attention because it happened after two failed starts last year.

ISRO chairman Dr K Radhakrishnan said the launch was successful and congratulated the scientists for the achievement.

The 1,206 kg Resoursesat-2 is an advanced remote sensing satellite and is fitted with three high resolution cameras. It will facilitate the study and management of natural resources.

With a five-year space life, Resourcesat-2 will replace Resourcesat-1 that was launched in 2003. It is also carrying an additional payload from Canadian COMDEV.

The second satellite, the YOUTHSAT will be used for stellar and atmospheric studies. The satellite with a two-year life is carrying two Indian and one Russian payload.

PSLV-C16 also launched Singapore’s X-SAT, a mini satellite that will be used for satellite-based remote sensing and onboard image processing.

Saturday, March 26, 2011

Life value.....

Sulekha Rani.R ,P.G.T chemistry,K V NTPC kayamkulam

The following is the philosophy of Charles Schultz, the creator of the "Peanuts" comic strip. You don't have to actually answer the questions. Just read the following straight through, and you'll get the point.
1. Name the five wealthiest people in the world.
2. Name the last five Heisman trophy winners.
3. Name the last five winners of the Miss America Contest.
4. Name ten people who have won the Nobel or Pulitzer Prize.
5. Name the last half dozen Academy Award winners for best actor and actress.
6. Name the last decade's worth of World Series winners.
How did you do?

The point is, none of us remember the headliners of yesterday. These are no second-rate achievers. They are the best in their fields. But the applause dies. Awards tarnish. Achievements are forgotten. Accolades and certificates are buried with their owners.



Here's another quiz. See how you do on this one:


1. List a few teachers who aided your journey through school.
2. Name three friends who have helped you through a difficult time.

3. Name five people who have taught you something worthwhile.
4. Think of a few people who have made you feel appreciated and special.
5. Think of five people you enjoy spending time with


Easier?


The lesson: The people who make a difference in your life are not the ones with the most credentials, the most money, or the most awards. They are the ones that care.