315,658 research outputs found
Remotely-actuated biomedical switch
Remotely-actuated biomedical switching circuit using transistors consumes no power in the off position and can be actuated by a single-frequency telemetry pulse to control implanted instrumentation. Silicon controlled rectifiers permit the circuit design which imposes zero drain on supply batteries when not in use
Improved ultrasonic biomedical measuring apparatus
Device for making measurements of organs in living specimens and recording movements of organs is described. System uses series of ultrasonic pulses beamed into body of animal and reflected echo pulses are picked up by transducers and recorded. Diagram of equipment required and method of application is included
Metal detector system
Signal voltage resulting from the disturbance of an electromagnetic field within the volume of a sensitive area is compared with a reference ac voltage for polarity information, which identifies the material. System output amplitude and polarity indicate approximate size and type of metal, respectively
Miniature implantable instrument measures and transmits heart function data
Heart diameter is derived from measured transit time of 2.25 MHz ultrasonic pulse between two piezoelectric crystals attached to diametrically opposite heart surfaces. Miniature instrument implanted in chest telemeters information to external receiver-converter. System permits continual dimensional data recording taken from awake animals during long-term experiments
Biomedical ultrasonoscope
An instrument with a single ultrasonic transducer probe and a linear array of transducer probes permitting three operator modes is described. An 'A' and an 'M' mode scanner were combined with a 'C' mode scanner and a single receiver is used. The 'C' scanner mode enables two-dimensional cross sections of the viewed organ. Video-produced markers enable measurement of the dimensions of the heart. COS/MOS integrated logic circuit components are used to minimize power consumption and permit battery operation
Deviations of the Lepton Mapping Matrix from the Harrison-Perkins-Scott Form
We propose a simple set of hypotheses governing the deviations of the
leptonic mapping matrix from the Harrison-Perkins-Scott (HPS) form. These
deviations are supposed to arise entirely from a perturbation of the mass
matrix in the charged lepton sector. The perturbing matrix is assumed to be
purely imaginary (thus maximally -violating) and to have a strength in
energy scale no greater (but perhaps smaller) than the muon mass. As we shall
show, it then follows that the absolute value of the mapping matrix elements
pertaining to the tau lepton deviate by no more than from their HPS values.
Assuming that can be neglected, we derive two simple
constraints on the four parameters , , ,
and of the mapping matrix. These constraints are independent of the
details of the imaginary -violating perturbation of the charged lepton mass
matrix. We also show that the and parts of the mapping matrix have a
definite form governed by two parameters and ; any deviation of
order can be accommodated by adjusting these two parameters.Comment: 31 pages, 2 figure
Jarlskog Invariant of the Neutrino Mapping Matrix
The Jarlskog Invariant of the neutrino mapping matrix is
calculated based on a phenomenological model which relates the smallness of
light lepton masses and (of ) with the smallness of
violation. For small violating phase in the lepton sector,
is proportional to , but and are proportional
to . This leads to . Assuming
, we find
, consistent with the present experimental
data.Comment: 19 page
Scanning seismic intrusion detection method and apparatus
An intrusion monitoring system includes an array of seismic sensors, such as geophones, arranged along a perimeter to be monitored for unauthorized intrusion as by surface movement or tunneling. Two wires lead from each sensor to a central monitoring station. The central monitoring station has three modes of operation. In a first mode of operation, the output of all of the seismic sensors is summed into a receiver for amplification and detection. When the amplitude of the summed signals exceeds a certain predetermined threshold value an alarm is sounded. In a second mode of operation, the individual output signals from the sensors are multiplexed into the receiver for sequentially interrogating each of the sensors
Ultrasonic biomedical measuring and recording apparatus
A train of ultrasonic pulses is beamed into the body of an animal. Organs intercepted by the beam reflect echo pulses following each transmitted pulse. An electronic gate with a variable width and a variable time delay relative to the transmitted pulse is utilized for selecting echoes derived from other organs or portions of organs. The integral of the echo signals received within the first half of the gate period is subtracted from a corresponding integral of the echo signal received during the second half of the gate to derive an error signal for controlling the time delay of the gate. In this manner, the selected echo signal is always maintained in the center of the gate
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