Transcript Nanotechnology Ralph C. Merkle Principal Fellow, Zyvex Health, wealth and atoms Arranging atoms • Diversity • Precision • Cost.

Nanotechnology
Ralph C. Merkle
Principal Fellow, Zyvex
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Health, wealth and atoms
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Arranging atoms
• Diversity
• Precision
• Cost
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Richard Feynman,1959
There’s plenty of room
at the bottom
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Eric Drexler, 1992
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President Clinton, 2000
The National Nanotechnology Initiative
“Imagine the possibilities: materials with ten
times the strength of steel and only a small
fraction of the weight -- shrinking all the
information housed at the Library of
Congress into a device the size of a sugar
cube -- detecting cancerous tumors when
they are only a few cells in size.”
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Today
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Arrangements of atoms
.
Today
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The goal
.
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Bearing
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Planetary gear
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Fine motion controller
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Robotic arm
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kbT
 
k
2
σ:
k:
kb:
T:
mean positional error
restoring force
Boltzmann’s constant
temperature
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kbT
 
k
2
σ:
k:
kb:
T:
0.02 nm (0.2 Å)
10 N/m
1.38 x 10-23 J/K
300 K
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Making diamond today
• Carbon
• Hydrogen
• Add energy
• Grow diamond film.
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Hydrogen abstraction tool
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Some other molecular tools
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Experimental work
H. J. Lee and W. Ho, SCIENCE 286, p. 1719, NOVEMBER 1999
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Self replication
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The Von Neumann architecture
Computer
Constructor
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Drexler’s architecure
for an assembler
Molecular
computer
Molecular
constructor
Positional device
Tip chemistry
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A C program that prints out
an exact copy of itself
main(){char q=34, n=10,*a="main() {char
q=34,n=10,*a=%c%s%c;printf(a,q,a,q,n
);}%c";printf(a,q,a,q,n);}
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English translation:
Print the following statement twice, the
second time in quotes:
“Print the following statement twice, the
second time in quotes:”
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An overview of self replicating systems
for manufacturing
• Advanced Automation for Space Missions,
edited by Robert Freitas and William Gilbreath
NASA Conference Publication 2255, 1982
• A web page with an overview of replication:
http://www.zyvex.com/nanotech/selfRep.html
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Complexity of
self replicating systems (bits)
•Von Neumann's
constructor
•Mycoplasma genitalia
•Drexler's assembler
•Human
500,000
1,160,140
100,000,000
6,400,000,000
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Exponential assembly
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The impact
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Powerful Computers
• We’ll have more computing power in the
volume of a sugar cube than the sum total
of all the computer power that exists in the
world today
• More than 1021 bits in the same volume
• Almost a billion Pentiums in parallel
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Nanomedicine
• Disease and ill health are caused largely
by damage at the molecular and cellular
level
• Today’s surgical tools are huge and
imprecise in comparison
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Nanomedicine
• In the future, we will have fleets of surgical
tools that are molecular both in size and
precision.
• We will also have computers much smaller
than a single cell to guide those tools.
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Human impact on the
environment depends on
• Population
• Living standards
• Technology
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Restoring the environment
with nanotechnology
• Low cost hydroponics
• Low cost solar power
• Pollution free manufacturing
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Lighter, stronger,
smarter, less expensive
• New, inexpensive materials with a strengthto-weight ratio over 50 times that of steel
• Critical for aerospace: airplanes, rockets,
satellites…
• Useful in cars, trucks, ships, ...
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Military applications of molecular
manufacturing have even greater
potential than nuclear weapons to
radically change the balance of
power.
Admiral David E. Jeremiah, USN (Ret)
Former Vice Chairman, Joint Chiefs of Staff
November 9, 1995
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Space
• Launch vehicle structural mass could be
reduced by a factor of 50
• Cost per kilogram for that structural mass
could be under a dollar
• Which will reduce the cost to low earth
orbit by a factor 1,000 or more
http://science.nas.nasa.gov/Groups/Nanotechnology/
publications/1997/applications/
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Nanotechnology offers ...
possibilities for health, wealth,
and capabilities beyond most
past imaginings.
K. Eric Drexler
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Quantum uncertainty
Born-Oppenheimer approximation
• A carbon nucleus is more than 20,000 times as
massive as an electron
• Assume the atoms (nuclei) are fixed and
unmoving, and then compute the electronic
wave function
• If the positions of the atoms are given by r1, r2,
.... rN then the energy of the system is:
E(r1, r2, .... rN)
• This is fundamental to molecular mechanics
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Quantum uncertainty
Ground state quantum uncertainty

 
2 km
2
σ2:
k:
m:
ħ:
positional variance
restoring force
mass of particle
Planck’s constant divided by 2π
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Quantum uncertainty
A numerical example
•
•
•
•
C-C spring constant:
Typical C-C bond length:
σ for C in single C-C bond:
σ for electron (same k):
k~440 N/m
0.154 nm
0.004 nm
0.051 nm
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Molecular mechanics
Basic assumptions
• Nuclei are point masses
• Electrons are in the ground state
• The energy of the system is fully
determined by the nuclear positions
• Directly approximate the energy from the
nuclear positions, and we don’t even
have to compute the electronic structure
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Molecular mechanics
Energy
Example: H2
Internuclear distance
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Molecular mechanics
Parameters
•
•
•
•
•
•
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Internuclear distance for bonds
Angle (as in H2O)
Torsion (rotation about a bond, C2H6
Internuclear distance for van der Waals
Spring constants for all of the above
More terms used in many models
Quite accurate in domain of
parameterization
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Pump
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Positional devices
I
I
Manipulation and bond formation by STM
Saw-Wai Hla et al., Physical Review Letters 85, 2777-2780, September
25 2000
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A hydrocarbon bearing
http://www.zyvex.com/nanotech/bearingProof.html
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Nanomedicine
•
•
•
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Killing cancer cells, bacteria
Removing circulatory obstructions
Providing oxygen (artificial red blood cells)
Adjusting other metabolites
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Nanomedicine
• By Robert Freitas, Zyvex Research
Scientist
• Surveys medical applications of
nanotechnology
• Volume I (of three) published in 1999
http://www.foresight.org/Nanomedicine
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• Today, loss of cell function results in
cellular deterioration:
function must be preserved
• With medical nanodevices, passive
structures can be repaired. Cell
function can be restored provided cell
structure can be inferred:
structure must be preserved
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Cryonics
Temperature
37º C
37º C
Restore
to health
Freeze
-196º C (77 Kelvins)
Time
(some decades)
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Clinical trials
•
•
•
•
Select N subjects
Freeze them
Wait 100 years
See if the medical technology of 2100 can
indeed revive them
But what do we tell those who don’t expect to
live long enough to see the results?
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What to do?
Join
the control group
or
the experimental group?
(www.alcor.org)
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