Abstract: A sealing arrangement has two bodies with two end faces which extend along a longitudinal axis, adjoin one another while forming a gap, the width of which can vary between zero and a maximum width. The gap is covered by a sealing strip which lies transversely to the gap, extends along the longitudinal axis and is mounted with clearance in two opposite grooves of a predetermined depth. In such a sealing arrangement, an increased maximum width of the gap is made possible by the sealing strip having a basic width transversely to the longitudinal axis, this basic width being less than or equal to twice the depth of the grooves, and by the sealing strip is constructed to prevent the sealing strip from slipping out of the grooves if the sum of the maximum width of the gap and the depth of the grooves is greater than or equal to the basic width of the sealing strip.

Abstract: A system for x-ray imaging of a small sample comprising positioning a tamper so that it is operatively connected to the sample, directing short intense x-ray pulses onto the tamper and the sample, and detecting an image from the sample. The tamper delays the explosive motion of the sample during irradiation by the short intense x-ray pulses, thereby extending the time to obtain an x-ray image of the original structure of the sample.

Abstract: In a sealing arrangement, in particular for the blade segments of gas turbines, two bodies, with two end faces which extend along a longitudinal axis, adjoin one another while forming a gap, the width of which can vary between zero and a maximum width. The gap is covered by a sealing strip which lies transversely to the gap, extends along the longitudinal axis and is mounted with clearance in two opposite grooves of a predetermined depth. In such a sealing arrangement, an increased maximum width of the gap is made possible by the sealing strip having a basic width transversely to the longitudinal axis, this basic width being less than or equal to twice the depth of the grooves, and by the sealing strip having additional means which prevent the sealing strip from slipping out of the grooves if the sum of the maximum width of the gap and the depth of the grooves is greater than or equal to the basic width of the sealing strip.

Abstract: In a sealing arrangement, in particular for the blade segments of gas turbines, two bodies, with two end faces which extend along a longitudinal axis, adjoin one another while forming a gap, the width of which can vary between zero and a maximum width. The gap is covered by a sealing strip which lies transversely to the gap, extends along the longitudinal axis and is mounted with clearance in two opposite grooves of a predetermined depth. In such a sealing arrangement, an increased maximum width of the gap is made possible by the sealing strip having a basic width transversely to the longitudinal axis, this basic width being less than or equal to twice the depth of the grooves, and by the sealing strip having additional means which prevent the sealing strip from slipping out of the grooves if the sum of the maximum width of the gap and the depth of the grooves is greater than or equal to the basic width of the sealing strip.

Abstract: A system for x-ray imaging of a small sample comprising positioning a tamper so that it is operatively connected to the sample, directing short intense x-ray pulses onto the tamper and the sample, and detecting an image from the sample. The tamper delays the explosive motion of the sample during irradiation by the short intense x-ray pulses, thereby extending the time to obtain an x-ray image of the original structure of the sample.

Abstract: Partial or total occlusions of fluid passages within the human body are removed by positioning an array of optical fibers in the passage and directing treatment radiation pulses along the fibers, one at a time, to generate a shock wave and hydrodynamic flows that strike and emulsify the occlusions. A preferred application is the removal of blood clots (thrombi and emboli) from small cerebral vessels to reverse the effects of an ischemic stroke. The operating parameters and techniques are chosen to minimize the amount of heating of the fragile cerebral vessel walls occurring during this photoacoustic treatment. One such technique is the optical monitoring of the existence of hydrodynamic flow generating vapor bubbles when they are expected to occur and stopping the heat generating pulses propagated along an optical fiber that is not generating such bubbles.

Abstract: A method of fitting an impingement plate to a platform of a guide blade of a gas turbine. The impingement plate is first fastened at individual spots by spot welds to at least one supporting surface of the platform and is then brazed at the supporting surface to the platform. The impingement plate is prefabricated with recesses and the spot welds are executed at the recesses.

Abstract: A method of fitting an impingement plate (5) is disclosed, the impingement plate (5) being brazed to a platform (2) of a guide blade (1) of a gas turbine. The impingement plate (5) is first fastened at individual spots by spot welds (7) to at least one supporting surface (10) of the platform (2) and is then brazed at the supporting surface (10) to the platform (2). The impingement plate (5) is prefabricated with recesses (8) and the spot welds (7) are executed at the recesses (8).

Abstract: An acoustic focusing device whose acoustic waves are generated by laser radiation through an optical fiber. The acoustic energy is capable of efficient destruction of renal and biliary calculi and deliverable to the site of the calculi via an endoscopic procedure. The device includes a transducer tip attached to the distal end of an optical fiber through which laser energy is directed. The transducer tip encapsulates an exogenous absorbing dye. Under proper irradiation conditions (high absorbed energy density, short pulse duration) a stress wave is produced via thermoelastic expansion of the absorber for the destruction of the calculi. The transducer tip can be configured into an acoustic lens such that the transmitted acoustic wave is shaped or focused.

Abstract: Partial or total occlusions of fluid passages within the human body are removed by positioning an array of optical fibers in the passage and directing treatment radiation pulses along the fibers, one at a time, to generate a shock wave and hydrodynamics flows that strike and emulsify the occlusions. A preferred application is the removal of blood clots (thrombin and embolic) from small cerebral vessels to reverse the effects of an ischemic stroke. The operating parameters and techniques are chosen to minimize the amount of heating of the fragile cerebral vessel walls occurring during this photo acoustic treatment. One such technique is the optical monitoring of the existence of hydrodynamics flow generating vapor bubbles when they are expected to occur and stopping the heat generating pulses propagated along an optical fiber that is not generating such bubbles.

Abstract: An acoustic focusing device whose acoustic waves are generated by laser radiation through an optical fiber. The acoustic energy is capable of efficient destruction of renal and biliary calculi and deliverable to the site of the calculi via an endoscopic procedure. The device includes a transducer tip attached to the distal end of an optical fiber through which laser energy is directed. The transducer tip encapsulates an exogenous absorbing dye. Under proper irradiation conditions (high absorbed energy density, short pulse duration) a stress wave is produced via thermoelastic expansion of the absorber for the destruction of the calculi. The transducer tip can be configured into an acoustic lens such that the transmitted acoustic wave is shaped or focused.

Abstract: This invention is an optically activated transducer for generating acoustic vibrations in a biological medium. The transducer is located at the end of a fiber optic which may be located within a catheter. Energy for operating the transducer is provided optically by laser light transmitted through the fiber optic to the transducer. Pulsed laser light is absorbed in the working fluid of the transducer to generate a thermal pressure and consequent adiabatic expansion of the transducer head such that it does work against the ambient medium. The transducer returns to its original state by a process of thermal cooling. The motion of the transducer within the ambient medium couples acoustic energy into the medium. By pulsing the laser at a high repetition rate (which may vary from CW to 100 kHz) an ultrasonic radiation field can be established locally in the medium.

Abstract: This invention is a catheter-based device for generating an ultrasound excitation in biological tissue. Pulsed laser light is guided through an optical fiber to provide the energy for producing the acoustic vibrations. The optical energy is deposited in a water-based absorbing fluid, e.g. saline, thrombolytic agent, blood or thrombus, and generates an acoustic impulse in the fluid through thermoelastic and/or thermodynamic mechanisms. By pulsing the laser at a repetition rate (which may vary from 10 Hz to 100 kHz) an ultrasonic radiation field can be established locally in the medium. This method of producing ultrasonic vibrations can be used in vivo for the treatment of stroke-related conditions in humans, particularly for dissolving thrombus or treating vasospasm.

Abstract: Fiber delivered laser pulses emulsify thrombus by mechanical stresses that include a combination of pressure, tension and shear stress. Laser radiation is delivered to the locality of a thrombus and the radiation is absorbed by blood, blood dot, or other present materials. The combination of a leading pressure wave and subsequent vapor bubble cause efficient, emulsification of thrombus. Operating the laser in a low average power mode alleviates potential thermal complications. The laser is operated in a high repetition rate mode to take advantage of ultrasound frequency effects of thrombus dissolution as well as to decrease the total procedure time. Specific parameter ranges for operation are described. The device includes optical fibers surrounding a lumen intended for flow of a cooling agent. The fibers may be arranged concentrically around the lumen to deliver radiation and heat over as large an area as possible.

Abstract: This invention is a catheter-based device for generating an ultrasound excitation in biological tissue. Pulsed laser light is guided through an optical fiber to provide the energy for producing the acoustic vibrations. The optical energy is deposited in a water-based absorbing fluid, e.g. saline, thrombolytic agent, blood or thrombus, and generates an acoustic impulse in the fluid through thermoelastic and/or thermodynamic mechanisms. By pulsing the laser at a repetition rate (which may vary from 10 Hz to 100 kHz) an ultrasonic radiation field can be established locally in the medium. This method of producing ultrasonic vibrations can be used in vivo for the treatment of stroke-related conditions in humans, particularly for dissolving thrombus or treating vasospasm.

Abstract: This invention is an optically activated transducer for generating acoustic vibrations in a biological medium. The transducer is located at the end of a fiber optic which may be located within a catheter. Energy for operating the transducer is provided optically by laser light transmitted through the fiber optic to the transducer. Pulsed laser light is absorbed in the working fluid of the transducer to generate a thermal pressure and consequent adiabatic expansion of the transducer head such that it does work against the ambient medium. The transducer returns to its original state by a process of thermal cooling. The motion of the transducer within the ambient medium couples acoustic energy into the medium. By pulsing the laser at a high repetition rate (which may vary from CW to 100 kHz) an ultrasonic radiation field can be established locally in the medium.

Abstract: A method and device are provided for performing intraluminal tissue welding for anastomosis of a hollow organ. A retractable catheter assembly is delivered through the hollow organ and consists of a catheter connected to an optical fiber, an inflatable balloon, and a biocompatible patch mounted on the balloon. The disconnected ends of the hollow organ are brought together on the catheter assembly, and upon inflation of the balloon, the free ends are held together on the balloon to form a continuous channel while the patch is deployed against the inner wall of the hollow organ. The ends are joined or "welded" using laser radiation transmitted through the optical fiber to the patch. A thin layer of a light-absorbing dye on the patch can provide a target for welding. The patch may also contain a bonding agent to strengthen the bond. The laser radiation delivered has a pulse profile to minimize tissue damage.

Abstract: A broadband diffractive lens or imaging element produces a sharp focus and/or a high resolution image with broad bandwidth illuminating radiation. The diffractive lens is sectored or segmented into regions, each of which focuses or images a distinct narrowband of radiation but all of which have a common focal length. Alternatively, a serial stack of minus filters, each with a diffraction pattern which focuses or images a distinct narrowband of radiation but all of which have a common focal length, is used. The two approaches can be combined. Multifocal broadband diffractive elements can also be formed. Thin film embodiments are described.

Abstract: Disclosed is an x-ray laser system comprising a laser containing generating means for emitting short wave length radiation, and means external to said laser for energizing said generating means, wherein when the laser is in an operative mode emitting radiation, the radiation has a transverse coherence length to width ratio of from about 0.05 to 1. Also disclosed is a method of adjusting the parameters of the laser to achieve the desired coherence length to laser width ratio.

Abstract: A broadband diffractive lens or imaging element produces a sharp focus and/or a high resolution image with broad bandwidth illuminating radiation. The diffractive lens is sectored or segmented into regions, each of which focuses or images a distinct narrowband of radiation but all of which have a common focal length. Alternatively, a serial stack of minus filters, each with a diffraction pattern which focuses or images a distinct narrowband of radiation but all of which have a common focal length, is used. The two approaches can be combined. Multifocal broadband diffractive elements can also be formed.