Spin-polarized electron energy loss spectroscopy or SPEELS is a technique that is mainly used to measure the dispersion relation of the collective excitations, over the whole Brillouin zone.
Spin waves are collective perturbations in a magnetic solid. Their properties depend on their wavelength (or wave vector). For long wavelength (short wave vector) spin wave the resulting spin precession has a very low frequency and the spin waves can be treated classically. Ferromagnetic resonance (FMR) and Brillouin light scattering (BLS) experiments provide information about the long wavelength spin waves in ultrathin magnetic films and nanostructures. If the wavelength is comparable to the lattice constant, the spin waves are governed by the microscopic exchange coupling and a quantum mechanical description is needed. Therefore, experimental information on these short wavelength (large wave vector) spin waves in ultrathin films is highly desired and may lead to fundamentally new insights into the spin dynamics in reduced dimensions in the future.
SPEELS is the one of the few techniques that can be used to measure the dispersion of such short wavelength spin waves in ultrathin films and nanostructures.
Today, I discussed my friend about two rigid beams impact and assuming no energy loss in the impaction.
As in the above figure, the upper beam move down with a uniform velocity ##v_c##, and hit a beam with ##0## velocity. After that the above beam will rotate and move away, which can be...
Homework Statement
Homework Equations
GPE=mgh
The Attempt at a Solution
I don't understand why the answer is B. My approach is assigning h a random value, say 10m. When the depths of water in both vessels are equal, the height is 5m. Therefore, since the mass of water in both vessels are...
Homework Statement
If 39.4 kW of power is to be transmitted from a generating station over two 0.141-Ω lines, estimate how much power is saved if the voltage is stepped up from 120 V(rms) to 1200 V(rms) and then down again, rather than simply transmitting at 120 V. Assume the transformers are...
EDIT: I accidentally put this thread into Engineering instead of Mechanical Engineering section, please move!
Hello all,
I am designing a system which will basically just stand in two different positions all the time by a compressed spring. The spring is pushing the system while the forces on...
Hey guys,
Im currently looking for a way to calculate the energy loss of a particle in a gas. This will help me to understand deposition processes better. The particles I am looking at are heavy, uncharged ones (e.g. metal atoms). Stopping power is not a viable concept without charge, and Bethe...
Homework Statement
After a lot of searching I can't seem to find a way to solve this. Basically, for a bouncing ball, if I know the dropped height and rebound height in a vacuum. How do I calculate the elasticity between the ball and the floor?
Homework Equations
K = 1/2 mv2
The Attempt at a...
Dear all,
I have inquiries about the Bohr's calculation for energy loss of charged particles. These inquires are from the "Techniques for Nuclear and Particle Physics Experiments" (W.Leo).
On page 23 of this book, it is written that:
the the interaction time is t = b/(γv), with b is the...
Homework Statement
what is the energy loss of the damped oscillator.
Homework Equations
x(t) = A*e^(-Bt)*cos(w1*t)
T = 1/2 mv^2
The Attempt at a Solution
To solve for an undamped oscillator, I took the derivative of the equation of motion x(t) and plugged the amplitude into 1/2 mv^2 equation...
Homework Statement
Two particles are in a perfectly inelastic collision with no external force acting on them. Particle 1 has m1 and v1>0. Particle 2 has mass m2 and v2<0. Find the loss in kinetic energy after the collision. Express your answer in
reduced mass as well as relative velocity...
Homework Statement
How would I go about finding the energy loss of a Pendulum from top (Ep) to Bot (Ek)
Mass= 2.0kg
Length= 0.38m
height= 0.05091m
theta= 30°
2. The attempt at a solution
I know that we could find Ep by going mgh (2.0kg)(9.81m/s)(0.05091m)=1.0J of Ep
But how...
I am aware that when charged particles accelerate or decelerate, the particle will emit a certain amount of radiation. But since a charged particle will accelerate any time it goes around a bend in a circuit, wouldn't it radiate some energy when it goes around the bend?
I thought that giving...
So I was thinking what are the differences between ionization and radiation energy loss for particles through a material?
Its weird cause I see the similarities but not seeing the differences...A friend brought it up in class today lol
Homework Statement
A (smooth) rope of length L and mass m is placed above a hole in a table. One end of the rope falls through the hole, pulling steadily on the remainder of the rope. Find the velocity of the rope as a function of the distance to the end of the rope, x. Ignore friction of the...
Homework Statement
I was asked to compare the energy loss of a system of two boxes moving towards each other, colliding elastically and in-elastically in two different situations that are not influenced by friction. There are no springs attached to either massThe Attempt at a Solution
I...
Homework Statement
The pendulum of a grandfather clock activates an escapement mechanism every time it passes
through the vertical. The escapement is under tension (provided by a hanging weight) and gives the
pendulum a small impulse a distance l from the pivot. The energy transferred by...
When following solutions like this link: http://physics.about.com/od/physicsmtop/g/PerfectlyInelasticCollision.htm
I understand that energy is lost, but it doesn't necessarily show that this is MAXIMUM energy loss, just that there is energy lost. How would you go about proving that more energy...
If I throw a ball vertically upwards from the surface of the earth, the upward motion slows due to gravity. At the ball's highest point, I have placed a repositioned platform for the ball to rest on; so it sits motionless, perched above the surface of the earth. When the ball began it's...
Hello,
In a MOS capacitor or MIS after applying a voltage on the metal, the valence band and the conduction band bend downwards
(in the usual band diagram) when a positive voltage is applied. (p-type semiconductor).
When the voltage is large enough, electrons forms an inverse layer(green)...
Homework Statement
A trolley is of mass 20kg is pushed 35 metres up an inclined plane (to a height of 10m above ground level). The inclined plane is at arcsin(2/7) to the horizontal. A 100N force pushes the trolley to the top of the plane, the force being parallel to the inclined plane. The...
http://www1.gantep.edu.tr/~physics/media/kunena/attachments/382/chapter2.pdf
On page 9 and 10 of the above PDF the method for deriving the fractional energy loss per cycle in a lightly damped oscillator is described.
I understand and follow this derivation.
What would the derivation...
Homework Statement
Hey everyone, trying to finish up a report and having a problem with getting to the final answer. It is a final report on hydro kinetic energy. We are planning to install a hydro kinetic turbine under a bridge and calculate what the energy output would be in KW. I am...
Firstly my knowledge of science is armchair tv level so any overly complicated explanations will be lost on me.
What is going on it terms energy conservation with the casimir effect.
As I understand it virtual particles created outside the plates have a greater range of wavelengths than...
Hello,
I am studying transformers now for the exam and I came across this question. It made a confusion in my mind. I took the photo of the question and put it into attachment.
The answers B and C looks very similar to each other and in my humble opinion both of them are true. I would be...
Considering the vibrational damping of bubble wrap. My basic premise is that there are three main contributors to the damping effect:
1) Surface tension of the sheet structure and the bubbles themselves when subject to applied force causes dissipation of force away from applied direction
2) The...
I have a lab in which a moving marble collides with a still one. What changes could I make to reduce the amount of kinetic energy loss in the collision? The track for the marbles is a piece of card stock paper.
I was thinking:
-Use two tubes as a track which will reduce the amount of...
I'm carrying on a research project in my school about roller coasters and I'm wondering if the following question is right.
I have a drag force which equation is \frac{1}{2}\rho·v^{2}·C_{D}·A where \rho is air density; v^{2} is squared velocity, C_{D} is drag coeficient and A is effective area...
I know air conditioners use a significant amount of energy, but turning the fan on high uses a fairly negligible amount. This started me thinking about the engine of the car.
Where do most of the losses occur? I know any time you have an energy conversion or transfer, you will be losing some...
Hi everyone!
I recently read a problem in a university textbook that read about an inelastic collision. There are two pucks (hockey?) on the ice, one at rest. Both the same mass, one approaches the other at a velocity and when they collide they stick together and both move off with a velocity...
Homework Statement
A ball of mass m = 1.9 kg moving with a speed of v0 = 20.1 m/s strikes an identical ball which was initially at rest. After the collision, the incoming ball (ball 1) goes off at q1 = 26° relative to its original direction and the struck ball (ball 2) moves off at q2 = 36° as...
hello,
i keep getting conflicting information on these and it confuses me
1) First my book says "In series circuit the voltage supplied by the cell is "shared" between all the components, so the more bulbs you add to a series circuit the dimmer they all become."
If you have a circuit...
Griffith's Problem 2.40 (a) and (b)
Suppose the plates of a parallel-plate capacitor move closer together by an infinitesimal distance ε, as a result of their mutual attraction.
a) Use
P= \frac{\epsilon_0}{2}E^2
to express the amount of work done by the electrostatic forces, in terms of...
Heat or deformation cannot contribute to velocity here, as per the view of conservation on momentum. So how is it that momentum is conserved but kinetic energy is not given a perfectly inelastic collision?
The two masses stick together.
There is no intrinsic means of expressing lost due to...
Homework Statement
(a) Consider a 10-Mev proton in a cyclotron of radius .5m. Use the formula (F1) to calculate the rate of energy loss in eV/s due to radiation.
(b) Suppose that we tried to produce electrons with the same kinetic energy in a circular machine of the same radius. In this case...
Homework Statement
A 500 MeV beam is scattered by a carbon target at 60 degrees. What is the energy loss (\omega or \nu) of the quasi-elastic peak? Ignore binding effects.
The Attempt at a Solution
This assignment is due tomorrow but we have yet to cover this material in my nuclear...
Homework Statement
I am working on a simulated lab in which we have a single particle projectile launched at a target particle (located at the center of the circular chamber) of similar weight. Once the collision takes place, I record the time it takes for the scattered projectile to travel...
Homework Statement
A particle of mass m_{1} and speed v_{1} collides with a second particle of mass m_{2} at rest. If the collision is perfectly inelastic what fraction of the kinetic energy is lost in the collision? Comment on your answer for the casses that m1 is much much smaller than m2...
Homework Statement
I need to estimate the energy loss of electrons before they reach a detector, but I am unsure how to do it. I think I am supposed to integrate the stopping power function over the total distance but I can't solve the equation...
Homework Equations
Stopping...
Googling for information on the topic leads me to graphs such as this, which suggest that if Beta and advance are optimal efficiency tops out at 85% or so. Some questions:
1) Is the ~15% lost energy converted to heat, or is there some stray kinetic energy in airflow that is somehow unusable as...
I know static friction can cause an object to accelerate, but also decelerate.
And i also know that static friction never cause energy loss, but I wonder when it causes an object to decelerate, its kinetic energy should decrease, so where is the mechanical energy gone? Has static friction done...
Here's a question I posted about 10 years ago as a member of the forum. No one seemed to provide a satisfactory answer then so maybe someone might have some ideas on the subject:
When a permanent magnet attracts an object it does work and loses energy.
When the object is pulled away is the...
Homework Statement
I am working on a energy analysis in a supermarket. There is some open top display coolers, which is using a lot of energy - I don't have the opportunity to check excatly how much energy they use, so I have to calculate it. I don't have problems in calculating it when it is...
kinetic energy loss??
A 2850 kg car moving east at 8.0 m/s collides with a 3200 kg car moving east. The cars stick together and move east as a unit after the collision at a velocity of 4.86 m/s.
(a) Find the velocity of the 3200 kg car before the collision.
2.06 m/s to the east
(b) What...
Homework Statement
A tube is bent into the form of a semicircle with centre O and radius r. It is fixed in a vertical plane with its diameter horizontal, as shown in the diagram. A steel ball is held at one end A, and released into the tube. Throughout its motion the ball experiences a...
Homework Statement
How was energy lost while using the ballistic pendulum?
Homework Equations
Initial KE= 1/2mb*Vb^2 = 0.929J
Final Potential graviational = (m+M)gh= 0.198J
Energy loss = 0.929J - 0.198J= 0.731J
The Attempt at a Solution
I think the answer is:
energy lost dues to...
Homework Statement
Two railroad cars, each with a mass of 7,000kg and traveling at 90 km/h collide head on and come to rest. How much mechanical energy is lost in this collision?
Homework Equations
KE=\frac{1}{2}mv^2
The Attempt at a Solution...
Homework Statement
I am writing my Extended Essay for IB, where I look at the possibility of obtaining accurate results in open system of a school, by accounting for all energy losses that occur during the investigation.
Before conducting my experiments (which included an air track with two...
Hi everyone!
Im having a project and i need to estimate the return hight of a falling yoyo
The yoyo is built of two 120cm radius and 2cm long cylinders connected by another one with a radius of 2.5cm and 30cm long. It is droped from the height of 30m with a rope that's 20m long.
How can i...
Hi, I'm new, so this may be on the wrong board, but I thought it was more particle-energy-stuff than astro.
So to the point - dark matter is non interacting with EM fields, and can't emit photons. Yes?
OK, given this, how could dark matter lose energy. For example, when normal matter is...
http://hyperphysics.phy-astr.gsu.edu/hbase/inecol.html
When a block in motion(M1) collides with a a stationary object (M2) in a perfectly inelastic collision, the fraction of KE final/KE initial can be modeled as M2/M1+M2.
My question is if M2 has to be stationary for this equation to...