Abstract: An analytical instrument includes an optical system having a source of incoming radiation (11) which in a transmission test is focused by a primary focusing element (15) onto a sample (16). The radiation transmitted through the sample is collimate by a focusing-collimating element (20) and directed across the beam of incoming radiation (14) before focused on a detector (12). To perform a test of the reflectance of the sample, an intercept element (28) is moved into position in the incoming beam (14) to deflect a portion (36) of the beam which is directed to the focusing-collimating element (20) and focused on the sample. The reflected radiation from the sample is collected by the focusing-collimating element (20) into a collimated beam (38) that is parallel and adjacent to the incoming beam, and which is directed in a path which passes by the intercept element (28) to be focused onto the detector (12).

Abstract: A sample changer for powder X-ray diffractometry includes a cylindrical dispensing container for holding a stack of pre-test sample holders, a cylindrical receiving container for holding a stack of post-test sample holders and a changer arm which automatically picks up the topmost sample disk in the dispensing container and rotatably positions the sample disk on the sample holder stage of an X-ray diffractometer for analysis. After analysis, the changer arm removes the sample holder and releases it into the receving container. The sample holders have a circumferential groove which coacts with semi-circular rotatable cams positioned on the distal end of the changer arm to enable the changer arm to lift and place the sample holders.

Abstract: A non-invasive, external ear canal electrode useful for transmitting sound stimulus to an ear canal and for conducting electrical signals picked up from the ear canal epidermal surface including a tube comprising electroconductive metal and having a resilient plastic foam element impregnated with an electrolytically conductive medium attached to the end to be placed in the ear.

Abstract: A radiation detection apparatus, such as for the detection of infrared radiation, is formed of inner and outer cylindrical stainless steel vessels with the inner vessels supported from the top wall of the outer vessel by a thin, relatively long stainless steel tube. A heat transfer mounting member is attached to the bottom of the inner vessel and extends outwardly and then upwardly between and out of contact with the vessels to the position of a window opening within the outer vessel. A detector device is affixed in good thermal contact with the mounting member at the position of the window and thus is maintained substantially at the temperature of the bottom surface of the inner vessel. The surfaces of the inner and outer vessels may be highly polished to prevent heat transfer to the inner vessel by infrared radiation. The use of stainless steel for the outer vessel also allows utilization of a vacuum port window structure having a metal gasket to minimize potential gas infiltration.

Abstract: A remote ion source within an ICR mass spectrometer which provides an enhanced trapping (within an analyzer cell) of ions formed within that remote ion source. In a preferred embodiment, trapping enhancement is accomplished by means of magnetic perturbations of the magnetic field within the analyzer cell. The perturbations may be established by ferromagnetic means or electromagnetic means or by the use of permanent magnets to form a magnetic bottle. Ions formed within the remote ion source are extracted from that source by an electrostatic lens and directed toward the analyzer cell along the Z axis of the spectrometer magnetic field. Deceleration lenses, external to the analyzer cell, may be employed to further enhance the trapping capability of the analyzer cell. In some modes of operation, a ramped deceleration potential may be applied to the declaration lens for "grouping" of ions of different masses for analysis. Provision for mass selection is also made within the spectrometer disclosed herein.

Abstract: A disk drive testing apparatus (20) is disclosed which provides substantially automatic cycling through various tests of disk drive units. A graphical display is provided on a screen (25) to the operator to allow the operator to determine whether the disk drive is performing in or out of specifications which may be read into the apparatus from an EEPROM memory module (26). By pressing a single TEST switch (22) on the tester, the operator can cycle through a preselected series of tests on the drive unit. The tester 20 is controlled by a microcomputer central processing unit (42) to cycle through the tests and to provide a display on the screen (25) for selected tests which includes a graphics field defining a performance reference frame including a geometric target specification position, a geometric pass range, and a geometric fail range.

Abstract: A method and apparatus for stimulating evoked potentials in a human subject maintains the common mode voltage at the stimulation electrodes substantially constant both before and during application of a stimulus pulse of constant current. A pair of resistors are connected between the stimulation electrodes and are joined at a reference node. One stimulation electrode (e.g., the anode) is connected through a field effect transistor to the power supply voltage and the other electrode (e.g., the cathode) is connected to the supply common return through a transistor which, when turned on, is controlled to conduct a constant current. The voltage at the reference node is supplied to the gate of a second field effect transistor which has its source clamped to a reference voltage. The voltage at the drain of the second field effect transistor is suppled back to the gate of the first field effect transistor.

Abstract: A mechanical pencil for automatic drawing machines is disclosed which feeds lead segments to the writing surface as the pencil is alternately pressed against and lifted from the writing surface. The pencil includes a housing having a reserve lead containment chamber and a main internal cavity. A collet split into two portions is mounted within the internal cavity beneath an opening between the main cavity and the containment chamber and has outer cone-shaped camming surfaces and first and second axially spaced, cylindrical inner clamping surfaces. A friction tube with an inner bore adapted to frictionally engage a lead segment is mounted beneath the collet and holds a lead segment to support it against the writing surface.

Abstract: A method for measuring channel-to-channel skew or phase difference in an electronic system of the type having a plurality of input channels which are sampled by sampling pulses having a frequency f.sub.o and a period P.sub.o. The sampling pulses at each input channel are first mixed with a reference signal having a frequency f.sub.r and a period P.sub.r that differ from the frequency and period of the sampling pulses. The mixing produces a beat signal at each input channel. A quantity termed "effective measurement interval" which is equal to the difference of the periods of the sampling pulses, P.sub.o, and the reference signal, P.sub.r, is computed. A quantity termed "apparent skew" which is equal to the number of periods P.sub.o of the sampling pulses which represents the skew or phase difference between the beat signals is also determined. Finally, skew or phase difference of the sampling pulses is computed by multiplying the "effective measurement interval" by the "apparent skew".

Abstract: An infrared spectroscopy instrument includes a housing having a sample chamber which is sized and shaped to accommodate the body of an automatic feeding slide projector of the type commonly utilized with standard photographic slide transparencies. The infrared beam is reflected by a system of mirrors into a beam path which extends through a portion of the slide projector mechanism ordinarily occupied by the projector lamp and optics, which have been removed. Samples are held in special sample holders adapted in size and shape to fit the compartments utilized in the slide magazine of the projector. These sample holders are indexed one at a time under the control of the instrument into a viewing position in the path of the infrared beam, and the beam passed through the sample is then collected and focused onto a detector.

Abstract: Apparatus and method for converting a conventional Michelson interferometer into a high resolution double-pass interferometer. The Michelson interferometer includes means for dividing an incident beam of radiation into first and second beams, means for propagating the first and second beams through first and second optical paths, respectively, means for recombining the first and second beams to form an output beam of radiation, and means for detecting an interference pattern in the output beam of radiation. The improvement comprises a beam splitter which is positioned to return a portion of the output beam of radiation to the interferometer as an incident beam of radiation, and a bandpass filter which is positioned between the beam splitter and the detector to filter from the output beam of radiation a portion which has been twice passed through the interferometer.

Abstract: A sample holder to influence the texture and size of particles of a sample and/or to induce crystallization process in cooled liquids or gases. The vibrational energy of an ultrasonic radiator is transferred to the sample. In this manner, identification of samples by powder diffractometry are easier, quantitative determinations are more precise, and diffractometry of samples with a melting point below room temperature are possible.

Abstract: A mass spectrometer of the type wherein a solenoidal magnet produces a magnetic field that includes a region along its geometric central axis. That region is a region of high field intensity and high homogeneity with magnetic flux lines in the region being generally parallel to the magnet central axis. A high vacuum is established in the region and a sample cell is positioned at or within the region in which sample ions are formed, trapped, excited and detected. An ionizing device is positioned outside of the region and off the central axis while an additional ionizing device may be positioned on the central axis. In a preferred embodiment, the off axis ionizing device may be supported for movement relative to the central axis. A preferred ionizing device for the off axis device is an electron gun.

Abstract: An interferometer spectrometer having a source of infrared analytical radiation, a fixed reflector, a moving reflector and a beam splitter for directing the analytical radiation to the reflectors. The beam splitter is formed of a semiconductor material which, in a preferred embodiment, is silicon. In a preferred physical embodiment, the beam splitter is configured as a wedge.

Abstract: A gas chromatograph/mass spectrometer interface for obtaining a mass spectrometer sample from the effluent of a gas chromatograph. The sample obtained in accordance with the present invention is essentially devoid of any carrier gas. A recording medium is located within a housing into which the effluent from the gas chromatograph is introduced. The temperature of the recording medium is below the freezing point of the sample portion of the effluent, such that the sample portion will freeze on the recording medium. A pressure regulator maintains a positive pressure within the housing to facilitate removal of the carrier gas portion of the effluent. The recording medium is transported within the housing during the freezing process such that different components of the sample are deposited on different portions of the recording medium. The sample is released from the recording medium for introduction into the mass spectrometer by heating the recording medium.

Abstract: A mass spectrometer of the type wherein the sample is ionized, excited into resonance and detected within a generally homogeneous magnetic field. During detection, the magnetic field is perturbed to form magnetic mirror regions to contain the ions. Prior to detection, the ions may be contained by conventional trapping techniques or by magnetic reflection.

Abstract: The flow of ink in a marking pen is metered by an internal flow restriction. The pen is of the type having a housing, including an ink reservoir, and a marking tip which draws ink from the ink reservoir by capillary action. The reservoir is vented to allow air to be drawn into the reservoir by the pressure drop created when ink is drawn out of the reservoir to the marking tip. A foam flow restrictor is positioned in the housing between the air vent and the ink reservoir to create a desired air flow rate into the reservoir and, in turn, a desired capillary action flow rate of the ink from the reservoir to the marking tip.

Abstract: A light-pipe flow cell (10) for high pressure fluids is disclosed which has a main support body (15) with a gold light-pipe element (22) mounted therein. Infrared transmissive windows (26, 27) are mounted to the main support body against sealing rings (31, 32) to seal off the polished central bore (23) of the light-pipe element from ambient atmosphere while allowing an infrared beam to be passed therethrough. Pressure plates (14, 18) are mounted to the main support body (15) to apply pressure to the windows over the sealing rings to tightly seal the windows without exerting undue stress thereon. Flow of liquid or supercritical fluid from a chromatography column is directed through inlet channels (35, 38) in the support body and light-pipe element to one end of the light-pipe bore (23) and out of the opposite end of the bore through a channel (41) in the light-pipe element and a communicating channel (36) in the main support body.

Abstract: A mass spectrometer including a vacuum chamber wherein molecular flow conditions are maintained. A sample introduced into the chamber is ionized while a magnetic field through the chamber induces ion cyclotron resonance. Trapping plates are provided for restricting ion movement along the magnetic field while a conductance limit plate divides the chamber into first and second compartments. The conductance limit plate has an orifice configured to allow ion equilibration between the compartments while maintaining a pressure differential between them. The conductance limit plate includes an electrode that is selectively connected to a means for applying trapping potential to selectively trap ions in one of said compartments.

Abstract: A graphic recording system wherein a plurality of recording elements are carried by a carriage, the carriage being movable in two directions along a path relative to a recording medium. An actuator selectively actuates the recording elements by mechanical engagement for recording on the medium. A rod having a longitudinal axis that is generally parallel to the path is supported, independently of the carriage, for rotation about its axis. An actuator arm is carried by the rod for rotation with the rod while being movable along the rod axis. Detents selectively interlock the actuator and carriage in predetermined relative positions. In a preferred embodiment, the detents are formed of slots within the carriage in predetermined relationships with the recording elements and a key rotatable with the actuator arm into and out of the slots.