Equations & Units Flashcards

1
Q

Frequency:

  • Equation?
  • Units?
A
  • f = 1/T
  • Hz, cycles/sec, per second
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2
Q

Period:

  • Equation?
  • Units?
A
  • T = 1/f
  • seconds
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3
Q

Pressure:

  • Equation?
  • Units?
A
  • pressure = force/area
  • Pascals (Pa)
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4
Q

Wavelength:

  • Equation?
  • Units?
A
  • wavelength = c/f
  • mm
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5
Q

Pulse Repetition Period (PRP):

  • Equation?
  • Units?
A
  • PRP = 1/PRF
  • seconds
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6
Q

Pulse Repetition Frequency (PRF):

  • Equation?
  • Units?
A
  • PRF = 1/PRP
  • Hz
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7
Q

Intensity:

  • Equation?
  • Units?
A
  • Intensity = power/beam area
  • mW/cm^2
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8
Q

Beam Uniformity Factor (BUF):

  • Equation?
  • Units?
A
  • BUF = SP/SA
  • No units
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9
Q

10 dB:

  • Equation?
  • Units?
A
  • dB = 10 log (I/I original); dB = 10 log (P/P original); dB = 20 log (A/A original)
  • No units
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10
Q

3 dB:

  • Equation?
  • Units?
A
  • Use step method (either half (negative) or double (positive))
  • mW/cm^2
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11
Q

Half Value Layer Thickness (HVLT):

  • Equation?
  • Units?
A
  • HVLT = 3 dB/f x AC
  • cm
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12
Q

Impedance:

  • Equation?
  • Units?
A
  • Impedance = density x velocity
  • Rayls (Z) or rayls (z)
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13
Q

Intensity Reflection Coefficient (IRC):

  • Equation?
  • Units?
A
  • IRC = Ir/Ii
  • %
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14
Q

Intensity Transmission Coefficient (ITC):

  • Equation?
  • Units?
A
  • ITC = It/Ii
  • %
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15
Q

Total Attenuation (TA):

  • Equation?
  • Units?
A
  • TA = AC x f x PL
  • dB
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16
Q

Density:

  • Equation?
  • Units?
A
  • Density = kg/m^3
  • kg/m^3
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17
Q

Incident Intensity:

  • Equation?
  • Units?
A
  • Ii = Ir + It;
    100% = %R + %T
  • %
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18
Q

%R:

  • Equation?
  • Units?
A
  • %R = [ z2 - z1/z2 + z1]^2
  • No units
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19
Q

Round Trip:

  • Equation?
  • Units?
A
  • RT = (%T)^2
  • %
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20
Q

Duty Factor (DF):

  • Equation?
  • Units?
A
  • DF = PD/PRP
  • No units
21
Q

Spatial Pulse Length (SPL):

  • Equation?
  • Units?
A
  • SPL = wavelength x # cycles in pulse
  • mm
22
Q

Axial Resolution:

  • Equation?
  • Units?
A
  • Axial Resolution = SPL/2
  • mm
23
Q

Frame Time:

  • Equation?
  • Units?
A
  • Frame Time = (13 us/cm) x (image depth (cm)/line) x (# line/frame)
  • us/frame
24
Q

Frame Rate (or Frame Frequency):

  • Equation?
  • Units?
A
  • Frame Rate = # of frames/frame time
  • MHz
25
Q

Q Factor (QF):

  • Equation?
  • Units?
A
  • QF = main frequency/bandwidth
  • No units
26
Q

Bandwidth (BW):

  • Equation?
  • Units?
A
  • BW = max - min
  • MHz
27
Q

Near Zone Length (NZL):

  • Equation?
  • Units?
A
  • NZL = (diameter ^2 x frequency)/(6 mm/us); NZL = (diameter^2)/(4 x wavelength)
  • mm
28
Q

Divergence of an angle:

  • Equation?
  • Units?
A
  • sin = (1.2 x wavelength)/diameter
  • ???
29
Q

Bernoulli’s equation:

  • Equation?
  • Units?
A
  • Constant = P + 1/2pv^2 + pgh
  • ???
30
Q

Pulsatility Index (PI):

  • Equation?
  • Units?
A
  • PI = (max - min)/average
  • No units
31
Q

Resistivity Index (RI):

  • Equation?
  • Units?
A
  • RI = (max - min)/max
  • No units
32
Q

Doppler Shift:

  • Equation?
  • Units?
A
  • Doppler Shift = reflected frequency - transmitted frequency
  • Hz
33
Q

Doppler Equation:

  • Equation?
  • Units?
A
  • fD = (2 x f original x v x cos)/c
  • ???
34
Q

Nyquist Limit:

  • Equation?
  • Units?
A
  • Nyquist Limit = PRF/2
  • MHz
35
Q

Equation of Continuity:

  • Equation?
  • Units?
A
  • Q = v x area;
    A1 x v1 = A2 x v2
  • ???
36
Q

Parallel:

  • Equation?
  • Units?
A
  • 1/ReQ = (1/R1) + (1/R2)
  • No units
37
Q

Law of Hemodynamics:

  • Equation?
  • Units?
A
  • change of P = Q x R
  • ???
38
Q

Capacitance:

  • Equation?
  • Units?
A
  • Capacitance = change in volume/change in time
  • ???
39
Q

Compliance:

  • Equation?
  • Units?
A
  • Compliance = change in volume/change in pressure
  • ???
40
Q

Poiseuille’s Law:

  • Equation?
  • Units?
A
  • Q = (pi x change in P x r^4)/8 x viscosity x L
  • ???
41
Q

Reynold’s Number (RN):

  • Equation?
  • Units?
A
  • RN = (P x v x diameter)/viscosity
  • No units
42
Q

Resistance:

  • Equation?
  • Units?
A
  • R = (8 x viscosity x L)/(pi x r^4)
  • ???
43
Q

Thermal Index (TI):

  • Equation?
  • Units?
A
  • TI = W original/W deg
  • No units
44
Q

Mechanical Index (MI):

  • Equation?
  • Units?
A
  • MI = (peak rare fractional pressure)/(f original)^1/2
  • ???
45
Q

Sensitivity:

  • Equation?
  • Units?
A
  • Sensitivity = TP/(TP + FN)
  • Fraction or %
46
Q

Specificity:

  • Equation?
  • Units?
A
  • Specificity = TN/(TN + FP)
  • Fraction or %
47
Q

Overall Accuracy (OA):

  • Equation?
  • Units?
A
  • OA = (TP + TN)/ (TP + TN + FP + FN)
  • Fraction or %
48
Q

Positive Predictive Value (PPV):

  • Equation?
  • Units?
A
  • PPV = [TP/(TP + FP)] x 100
  • Fraction or %