Supersonic Jet Screech: Half-century from Powell to the Present

A method of manufacturing a semiconductor device is provided which uses a laser crystallization method capable of increasing substrate processing efficiency. An island-like semiconductor film including one or more islands is formed by patterning (sub-island). The sub-island is then irradiated with laser light to improve its crystallinity, and thereafter patterned to form an island. From pattern information of a sub-island, a laser light scanning path on a substrate is determined such that at least the sub-island is irradiated with laser light. In other words, the present invention runs laser light so as to obtain at least the minimum degree of crystallization of a portion that has to be crystallized, instead of irradiating the entire substrate with laser light.

Laser irradiation method and method of manufacturing a semiconductor device

Providing a semiconductor fabricating apparatus using a laser crystallization technique for enhancing the processing efficiency for substrate and for increasing the mobility of a semiconductor film. The semiconductor fabricating apparatus of multi-chamber system includes a film formation equipment for forming a semiconductor film, and a laser irradiation equipment. The laser irradiation equipment includes first means for controlling a laser irradiation position relative to an irradiation object, second means (laser oscillator) for emitting laser light, third means (optical system) for processing or converging the laser light, and fourth means for controlling the oscillation of the second means and for controlling the first means in a manner that a beam spot of the laser light processed by the third means may cover a place determined based on data on a mask configuration (pattern information).

Semiconductor fabricating apparatus

In manufacturing a semiconductor device, static electricity is generated while contact holes are formed in an interlayer insulating film by dry etching. Damage to a pixel region or a driving circuit region due to travel of the static electricity generated is prevented. Gate signal lines are spaced apart from each other above a crystalline semiconductor film. Therefore a first protective circuit is not electrically connected when contact holes are opened in an interlayer insulating film. The static electricity generated during dry etching for opening the contact holes moves from the gate signal line, damages a gate insulating film, passes the crystalline semiconductor film, and again damages the gate insulating film before it reaches the gate signal line. As the static electricity generated during the dry etching damages the first protective circuit, the energy of the static electricity is reduced until it loses the capacity of damaging a driving circuit TFT. The driving circuit TFT is thus prevented from suffering electrostatic discharge damage.

Semiconductor Device and Method of Manufacturing the Same

A method for using a miniscale ballistic test motor for determining burn es over an operating pressure range allows the testing of a small propellant sample. The small propellant sample allows performance of an abbreviated procedure for each test of the propellant sample involving loading of a small scale test motor with the sample, conditioning the test motor and sample therein, firing the propellant sample and recording data.

Miniscale ballistic motor testing method for rocket propellants

A method for determining the burning rate of a propellant. The method involves the single firing of a subscale, propellant motor that has been modified so that the propellant motor has a tapered cylindrical port that produces a non-neutral pressure-time trace when burned. The pressure-time trace is initially progressive (pressure increases with time), and then regressive (pressure decreases with time). Unlike conventional motors, this motor operates over a range of burning rates; therefore, the burning rate behavior of the propellant can be characterized with a single motor firing. The burning rate of the propellant is extracted from the motor pressure-time history by a computer analysis package. The analysis package employs an optimization program which uses an internal ballistics model of the motor. The ballistics model is used to generate a theoretical pressure-time trace which can be compared with the digitized output signal from the actual motor. The optimization routine of the computer determines the propellant burning rate behavior by selecting the burning rate law which, when employed in the internal ballistics model of the motor, produces the best match between the computer generated and the actual motor pressure-time traces. Thus by using the tapered port motor and by reducing the data, the burning rate of a propellant can be characterized with a single motor firing.

Method for burning rate characterization of solid propellants

An analysis for predicting the performance of side-exhausting scarfed propulsive nozzles is presented. Nozzles of this type consist of a conventional axisymmetric nozzle followed by a scarfed conical extension. They are employed in situations where the exhaust jet must exit through the side of a missile. The flowfield model assumes that the flow within the nozzle is axisymmetric, and that the overall nozzle pressure ratio is high enough to preclude shock waves or flow separation at the nozzle exit. The flowfield is calculated by the method of characteristics. The oblique shock wave that emanates from the junction of the nozzle and the nozzle extension is fitted discretely and tracked through the flowfield. The forces and moments acting on the scarfed nozzle and the missile are determined. The results of an extensive parametric study are presented. Comparisons with experimental measurements are presented to verify the analysis.

Performance analysis of scarfed nozzles

A propulsion system is disclosed comprising a glycidyl azide polymer (GAP)olid fuel generator (SFGG) that produces fuel-rich hot gases which are combusted in a combustion zone of a combustion chamber of a solid fuel ducted rocket. A basic embodiment comprises an airbreathing engine wherein a ducted member scoops air in from the atmosphere for hypergolic reaction with the fuel-rich hot gases for propulsion during a sustain stage of a flight. An augmentation of the basic embodiment is achieved by combusting the fuel-rich GAP SFGG effluent with inhibited red fuming nitric acid (IRFNA) gel oxidizer to produce higher thrust during the boost and dash stages of a flight. During the high thrust stages, the air ducts of the ducted member are closed and IRFNA gel is injected into the combustion chamber to react with the fuel-rich hot gases from the GAP SFGG. The resulting higher pressure in the combustion chamber gives the missile a correspondingly greater thrust than during the lower pressure airbreathing sustain stage of flight.

Solid fuel ducted rocket with gel-oxidizer augmentation propulsion

A methodology for the design and optimization of tactical solid propellant propulsion systems employing scarfed nozzles is presented. A performance prediction computer code based on an axisymmetric flowfield model and utilizing the method-of-characteristics solution technique is employed as the primary analysis tool. This performance code is used through a series of parametric studies to obtain a performance map for lengthconstrained scarfed nozzles. The results of these parametric studies are curve-fitted to relationships that express scarf-nozzle performance as a function of nozzle geometric parameters. The relationships are differentiated to obtain the set of geometric parameters for a given nozzle projected length, which maximizes the motor axial performance. The set of optimum geometric parameters for each given nozzle projected length is employed in additional curve fits. These curve fits are used to express the optimum values of the geometric parameters and the corresponding optimum performance as a function of nozzle projected length. The curve fits for the optimum quantities are used to develop a series of relationships that expresses the length of a tactical propulsion system as a function of projected nozzle length. These system relationships are employed to obtain the nozzle geometry, which minimizes the propulsion system length for a specific delivered impulse requirement. The results of this study provide the propulsion system designer with a methodology for selecting the optimum nozzle design for length-constrained applications.

Design and optimization of propulsion systems employing scarfed nozzles

The results of an experimental investigation into the performance of scarfed nozzles are presented. This investigation was conducted to establish the range of applicability of a performance prediction model. Factors that influence the applicability of the model are the presence of three-dimensional flow and/or boundary-layer separation. The influence of these factors on the performance of scarfed nozzles was experimentally investigated by statically firing specially designed solid rocket motors that employed various scarfed nozzle configurations. The data from these firings were used to determine applicability limits for the performance model. The results of the test program and the applicability limits obtained are presented.

Jay S. Lilley

Papers

Method for burning rate characterization of solid propellants

Performance analysis of scarfed nozzles

Solid fuel ducted rocket with gel-oxidizer augmentation propulsion

Design and optimization of propulsion systems employing scarfed nozzles

Experimental validation of a performance model for scarfed nozzles