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1. The Dipole
- www.scs.uiuc.edu
- The Dipole.
- The Dipole is a web-based newsletter that was started at the Zeta chapter by Robin Fishbein. The Dipole is now a fraternity based newsletter that can be accessed at Robin's Corner.
2. Magnetic Dipole Radiation From a Dipole That Turns Off
- web.mit.edu
- Magnetic Dipole Radiation From a Dipole That Turns Off.
- The field lines of a magnetic dipole for the case where the dipole moment falls to zero over a time scale T. The specific time dependence of the dipole moment is proportional to (Pi/2-arctan(t/T))/Pi, which is a function which is 1 at t = -infinity and zero at t = + infinity, and falls to zero in a characteristic time T. ...
3. Magnetic Dipole Radiation From A Sinusoidally Varying Dipole--The Transition/Far Zone
- web.mit.edu
- Magnetic Dipole Radiation From A Sinusoidally Varying Dipole--The Transition/Far Zone.
- The field lines of a magnetic dipole for the case where the dipole varies sinusoidally in time by 10% in amplitude (20% peak to peak). That is, the dipole is always oriented along the vertical axis, and its dipole moment varies in time in a manner proportional to (1. ...
4. Definition: dipole antenna
- www.its.bldrdoc.gov
- dipole antenna.
- dipole antenna: Usually a straight, center-fed, one-half wavelength antenna. ...
5. The Subwoofer DIY Page v1.1 - Dipole Bass Systems
- www.diysubwoofers.org
- Dipole Bass Systems.
- Dipole Bass Design .
- dipole. ...
- Dipole subwoofers are quite different to the other subwoofer systems described on this site because of the way they treat the the driver's output. ... However, for dipole bass systems, the rear radiation is left untreated, and instead the overall response of the system is adjusted by varying the size of the baffle and the "Q" of the system to achieve the best overall response characteristics.
- The drivers used in dipole systems tend to be quite different to those in "monopole" bass systems. ... Alternatively, a "normal" driver can be used in a dipole bass system, but a considerable amount of equalization may have to be used to make up for the loss in low frequency performance.
- A dipole bass system has a "figure of eight" response pattern, which is entirely different to the "spherical" response pattern of your typical "monopole" subwoofer. ... This response characteristic is said to be one of the major advantages of a dipole bass system, as the restricted dispersion results in fewer boundary reflections, which in turn is supposed to result in a smoother in-room response. ...
- Dipole bass systems tend to be rather large, employing multiple drivers, primarily to make up for the output reduction due to the 6dB/oct baffle loss. ...
- The tradeoff here is efficiency; the smaller the baffle, the lower the final efficiency of the dipole system. ...
- Almost all dipole bass designs incorporate some means of boosting the response at low frequencies to compensate for the baffle loss. ...
- Linkwitz Lab Phoenix - Dipole Woofer .
- John Forasiepi's Dipole Bass subwoofers .
- J Newman, "Dipole Radiator Systems", JAES Jan/Feb 1980 .
- Linkwitz Lab - Models for a dipole loudspeaker design .
6. Rigging up a dipole arial
- www.zoo.co.uk
- Rigging up a dipole arial .
- He fitted an external dipole aerial, and now listens in glorious stereo again. Here's the basic facts on how to fit a dipole aerial. ...
- The simplest FM antenna is a dipole: two wire sticks poking out in opposite directions from a central connection. ...
- A 75ohm impedance socket takes a simple half wave dipole arial connected to your set via TV type coaxial cable. ...
- A 300ohm impedance socket takes a folded half wave dipole arial connected to your set via a flat ribbon cable - the sort often supplied for indoor use, sellotaped behind the curtains. The folded dipole aerial has the ends of its dipoles looped back and joined to each other to create the extra impedance required to balance the aerial circuitry. ...
- If you have the 75ohm type, consider buying a manufactured dipole from your local supplier (try Potts in Derby) - but you can make one from bits of wire and wood! .
- This is a dipole aerial with one or more extra poles in an 'H' shape. The extra poles channel and reflect the signal onto the central dipole. ...
- Radio Derby's signal is of the 'mixed polarization' type, which means you can mount the dipole vertically or horizontally (or even diagonally): vertically will usually be more convenient. ...
- The looped element is the dipole; behind it is a reflector; in front are two directing elements facing towards the radio transmitter.
- Making your own 75ohm dipole.
- Nails for fixing the dipole to the wood. ...
- Fix the two 70cm lengths of wire (the dipole) to the wood in line so they nearly touch in the middle. ...
- Connect the coax cable to the dipole where they nearly touch - the centre conductor to one, the outer sheilding conductor to the other, it doesn't matter which. ...
7. Dipole With Boom - Simulating Thick Wire - ASAP Examples
- home.att.net
- A Dipole with a Boom Simulating Thick Wire .
- Simulating a conductive Boom near a Dipole element. ...
- In the case of the near field of the dipole we can try just a rectangular grid as shown below. ...
- Since the near field of the dipole is dominant parallel to the dipole, the "ladder" cross-bars are also turned parallel to the dipole. ...
- Below is a figure of a dipole (thin rod shown vertical) that is near a conductive boom (thicker rod shown horizontal). ...
- The figure below shows conceptually the dipole and the boom after they have been segmented for analysis. The dipole, represented in the color red, is modeled as a single thin-wire structure. ...
- In the problem being considered, the dipole is described with 51 points joined to make 50 segments. The dipole is fed at the center point. The dipole is 0. ... These wires are at right angles to the dipole wire element and spaced 4 cm away. Therefore, the dipole is insulated from the boom for this problem. ...
- The dipole by itself and the dipole with the ladder boom simulation were run for multiple frequency points to gauge the effect on feedpoint impedance of the dipole. ...
- A half-wave dipole in free space resonates at a frequency that is lower than the free-space half-wavelength. ... 5 meter dipole will be above the resonance frequency at 300 MHz as is confirmed by the model showing positive reactance number. Even though the dipole is not "at resonance" in this example, the shift in effective response can still be noted from the curves. ... In one sense, this means that the dipole appears to be effectively shorter with the boom than it would be in free space. The dipole would have to be lengthened slightly in order for it to act "the same" as it would in free space. ...
8. Figure 1
- www.biomedical-engineering-online.com
- Only 5 of the 23 temporal and 7 of the 23 parietal dipole locations are shown. Each location is used to simulate the potentials of a tangential and radial dipole.
9. The electric dipole approximation
- farside.ph.utexas.edu
- The electric dipole approximation .
- This approximation is known as the electric dipole approximation. ...
- These are termed the selection rules for electric dipole transitions. It is clear, for instance, that the electric dipole approximation allows a transition from a state to a state, but disallows a transition from a to a state. ...
- Instead, they take place at a far lower rate than transitions which are allowed according to the electric dipole approximation. After electric dipole transitions the next most likely type of transition is a magnetic dipole transition, which is due to the interaction between the electron spin and the oscillating magnetic field of the incident electromagnetic radiation. Magnetic dipole transitions are typically about times more unlikely than similar electric dipole transitions. ... These are typically about times more unlikely than electric dipole transitions. Magnetic dipole and electric quadrupole transitions satisfy different selection rules than electric dipole transitions; for instance, the selection rules for electric quadrupole transitions are. Thus, transitions which are forbidden as electric dipole transitions may well be allowed as magnetic dipole or electric quadrupole transitions. ...
10. Dipole Transitions
- newton.ex.ac.uk
- Dipole transitions.
- An optical (electric dipole) transition can be forbidden by symmetry. ... If the product contains the irreducible representation that corresponds to the dipole (x, y, and/or z), then the transition is allowed in principle. ...
- Equivalently, if the product irreducible representations of the ground, excited and dipole-operator contains the totally symmetric irreducible representation, then the transition is allowed. ...
- is the irreducible representation of the dipole operator.
- In a similar way, vibrational replicas of dipole transitions follow the selection rule: GS p XS LVM Sym.
- Note, dipole forbidden transitions follow the same selection rule, and consequently totally symmetric modes cannot be phonon replicas of forbidden transitions. ...
11. Onset of collective low-energy dipole resonances
- www1.physik.tu-muenchen.de
- Next: Conclusions Up: Collectivity of the low-lying Previous: Low-lying dipole strength in .
- Onset of collective low-energy dipole resonances .
- Results of the isovector dipole strength distributions are shown in the Fig. ... Apart from the increase of the dipole strength, large relative contribution in low-energy region E 10 MeV is also observed; the ratio of energy weighted moments, varies from 0. ... 3% EWSR), with many particle-hole pairs contributing to the corresponding dipole strength. ... Low-lying dipole strength in Ni has the similar structure of fragmented RRPA amplitudes among several possibilities of excitation. ... The Steinwedel and Jensen hydrodynamic two-fluid model of the core and excess fluid describes the onset of pygmy dipole resonance in which the neutron excess move against the core 12 . ...
- where refers to the number of neutrons that form the core together with protons, and is energy of the giant dipole resonance. Comparison of RRPA centroid energies of the low-lying dipole strength and pygmy resonances in hydrodynamical model 12 in the case of nickel isotopes is presented in the lower part of Fig. ... 9), the RRPA GDR-energies are compared with the approximate relation describing mass dependence of the isovector giant dipole resonance (the best in nuclei), obtained by fitting to the experimental results 1 . ... In contrast to the RRPA results, the Steinwedel and Jensen hydrodynamical model 12 predicted that the Pygmy dipole resonance (PDR) energy increase with increasing number of excess neutrons. ...
- Isovector dipole response to the RRPA states for the Sn,Sn, Sn and Sn nuclei is displayed in the Fig. ... Therefore, the corresponding dipole strength is mostly determined by several p-h excitations from the orbitals of excess neutrons. ...
- 8 MeV, proton and neutron transition densities display a usual radial dependence of isovector giant dipole resonance, with proton and neutron densities oscillating in opposite phases. ... In the case of many p-h configurations contributing to the low-lying state, this behavior of transition densities can be interpreted as a collective oscillation associated with the pygmy dipole resonance. ...
- Finally, let us investigate the isovector dipole response of medium heavy nuclei with extremely large number of neutrons. ...
12. Molecules test electron dipole (February 2002) - News - PhysicsWeb
- physicsweb.org
- Molecules test electron dipole.
- Physicists are closer to finding out if the electron is a point charge or whether it has an internal distribution of charge known as an electric dipole moment. For the first time, Ed Hinds and colleagues at Sussex University have measured the electron’s electric dipole moment using molecules rather than atoms. ...
- The electron’s electric dipole moment is a measure of the average distance of charge from the electron’s centre of mass. The dipole moment is parallel to the direction in which the electron spins because any other component of charge distribution would be averaged to zero by the motion of the spin. This implies that the product of an electron’s spin and electric dipole moment is an intrinsic property of the electron. Since the spin reverses if time runs backwards, the dipole moment must be zero if the electron is not to violate ‘time-reversal symmetry’ – a postulate of the Standard Model. ...
- Measurements of the electric dipole moment exploit the tendency of the dipole moment to align itself with an applied electric field and cause the spin of the electron to precess like a gyroscope. Physicists then compare the energy imparted by the field when the dipole moment is parallel and anti-parallel to the field. ...
- The virtue of measuring the dipole moment of electrons in molecules rather than heavy atoms – which are currently used – is that they can generate far higher electric fields and therefore mask the unwanted magnetic effects. ...
- Hinds and co-workers have developed an interferometer that measures the dipole moment in a beam of ytterbium fluoride molecules. ... Any electric dipole would impart different energies to the two states, changing their relative phase. ...
- The researchers have established an upper limit to the dipole moment of around 3 x 10-26 ecm, which is less accurate than the measurement carried out last year - 10-27 ecm – made by Chris Regan and Eugene Commins of the University of California at Berkeley. ...
- However, Hinds estimates that molecular measurements will improve on this accuracy within a few years and allow physicists to discriminate between rival advanced theories of particle physics, which predict different values of the dipole moment. ...
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