Transcript Document

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An initiative on the NATIONAL SCIENCE DAY
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For a write up on the context or else
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An Example for Classroom
Demonstration
An Introductory Illustration for the
Nuclear Magnetic Resonance
LARMOR Precession
Total 7 slides:: About 10 minutes SHOW_TIME ::Times set for Automatic slide transition ::
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nuclear precession in magnetic field
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Quantization of
Nuclear Spin Components
An Animated Illustration
Spin Axis
A visualisation as to
what could happen
No well defined
when
thereforisthe
NOspin
direction
chosen
direction
axis specified
outside
relevant
and relatable
the spinning
nucleus?
to the SPIN AXIS
Spinning
nucleus
Spin Axis
may be
along the
chosen
axis also
When an axis
is defined
But no Quantization requirements
for the Components of Spin
When an Axis
is defined
& Components of
Spin Vector can be
quantized
Spin Vector Component in the presence of a
chosen axis is quantized and has fixed orientation
Nucleus
has mass ‘M’
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What is the Interaction by which a
direction can be specified as relatable
to the quantization that manifests?
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Consider the questions carefully. It would require
a revision of College Physics----Chapters on
Magnetism
Till now only the MASS of the nucleus has been spelt out. If
necessary get back to the slide#1 and view for a revision.
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display of next line below
Can you consider and explain the Nuclear Spin
Quantization Without taking into consideration the
associated Charge of the nucleus.
Slide #4 is an animated illustration of the Spin Precession
which is to be descriptively summarized in words
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Spin Precession Animation “DEMO”
The Nucleus would
continue to precess; only
as long as the Magnetic
Field is on - - - - - - - -
- ->
Precession Starts
on application of
Magnetic Field
Animation in this
slide only one cycle
of the Larmor
precession
MAGNETIC
FIELD
μXH
SPIN
Iħ
MAGNETIC
MOMENT
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Return to(#1) first
slide
Nuclear Spin
nuclear precession in magnetic field
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North Eastern Hill University Shillong 793022 Meghalaya
NEHU Campus
Centre For Bioinformatics (BIC)
National Science Day at BIC on 28th February 2003
Jottings ……….!!! Over The Happenings::
S.Aravamudhan, Department of Chemistry,
NEHU
It was a fine morning on the 28th February 2003 when I was seated in front of
a P.C. at the Centre for Bioinformatics. I had just-few days before- returned
after attending two National symposia and the attention was not to have too
much backlash in returning and resuming the activity here. I was simply trying to
set at rest a question, which arose one of these days as to how simple it would
be to provide an animated illustration of the principles of Physics at work, when
the nuclei precess under the duress of Magnetic Field Strength. It was mostly
trying to reproduce a simple drawing several times; place all these copies close
enough with such displacements which can enable them to flash once in succession
in such a sequence that it appears as if a single and same object is moving
around!
Continues in next slde………
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With such an obsession to enable pseudo dynamism, the reality sounded like a
dream when a voice could be heard over my shoulders pronouncing, “excuse me”.
My glance over my shoulders could vindicate that it was none other than
Prof.P.Tandon who wished that I should take part in the National Science Day
proceedings scheduled to begin at that moment in the centre.
In fact, I was reminded emphatically by the incident, more than my mere routine
awareness of the date 28th Feb. 2003, that the 28the February is National
Science Day.
On this occasion I had the opportunity to tell the gathering about the 28th
February during 1979-’80, when I was called upon to be one of the speakers at
the National Chemical Laboratory, PUNE when there was a function to
commemorate the ( anniversary of ) Discovery of Raman Effect. I had the
pleasant assignment of having to talk on Fourier transform Nuclear magnetic
Resonance Spectroscopy as an Introductory Note for half-an-hour which was to
be followed by people who were applying this technique and were to speak on the
examples of applications.
I could also share with the audience on this occasion on 28th Feb. 2003 at NEHU,
the thrill I experienced while I happened to hear Sir C.V. Raman speak on
“Diamonds” and the way he could pronounce and reverberatingly utter the word
BRILLIANT (in his own characteristic brilliance at diction) while explaining why
the diamonds appear to be source of light rays and have the brilliance for optical
descriptions. He could mention in a few pulsating moments all about the reflection
of light, the consequences of refraction of light rays and effectively clarify the
phenomenon of Total Internal Refection.continues in next slide….
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The discovery of the unusual light scattering, by the inquisitive and observant
individual C.V.Raman has contributed to the molecular spectroscopic technique so
immensely that the front line applications seem only to further widen the ripple
set out by the discovery of Raman Effect, and, infringe upon the states of
matter not only at molecular level. The vibrational modes which are forbidden by
selection rules in the conventional infrared spectroscopy became manifest in the
Raman Spectra. Hence this discovery seems to have made it a wholesome
spectroscopic technique by tying the lose ends necessarily to infer the molecular
vibrational (structures) features which are covered by the infrared region of the
electromagnetic radiation spectrum.
The concerned, indulgent and witty speeches by the students/staff/teachers on
this occasion would have engrossed those present much longer but for the mouthwatering refreshments made available. This provided the necessary grease to
continue the grinding to impressively flash objects to be apparently a moving
object!
End of
narration.
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