Abstract: The present invention is directed to a process or method for preparing a metal fluoride pre-melt material of a quality suitable for the preparation and growth of metal fluoride optical monocrystals. The pre-melt material of the invention is prepared using permeable graphite crucibles having a permeability (porosity) greater than 4 cm2/s. Exemplary monocrystals prepared from pre-melts of the invention exhibited improved transmissivity and laser durability relative to monocrystals prepared from convention pre-melt materials. Impurities in the pre-melt arising from the use of scavenger/fluorinating agent in the pre-melt have been shown to be generally less than 10 ppb and be less than 1 ppb.

Abstract: The invention is directed to method of preparing metal fluoride single crystals and particularly to crystals where the metal is calcium, barium, magnesium or strontium, or a mixture thereof. The invention uses a decreasing fast cooling profile and an increasing slow cooling profile for the hot zone and the cold zone, respectively, after crystal formation during cooling from melt temperatures to a first temperature. A substantially constant cooling rate is then applied to the both zones during cooling from the first temperature to a final temperature, usually room temperature. It has been found that the substantially constant cooling rate during the annealing process results in crystals having improved homogeneity and birefringence.

Abstract: A method of making an oriented calcium fluoride single crystal includes loading calcium fluoride feedstock on top of a seed crystal having a specific crystallographic orientation, heating the calcium fluoride feedstock to a temperature sufficient to form a melt, and growing a calcium fluoride crystal on the seed crystal by progressively moving the melt and the seed crystal through a temperature gradient zone having an axial temperature gradient in a range from approximately 2° C./cm to approximately 8° C./cm, wherein a growth direction of the calcium fluoride crystal substantially conforms to the crystallographic orientation of the seed crystal.

Abstract: The present invention is directed to a process or method for preparing a metal fluoride pre-melt material of a quality suitable for the preparation and growth of metal fluoride optical monocrystals. The pre-melt material of the invention is prepared using permeable graphite crucibles having a permeability (porosity) greater than 4 cm2/s. Exemplary monocrystals prepared from pre-melts of the invention exhibited improved transmissivity and laser durability relative to monocrystals prepared from convention pre-melt materials. Impurities in the pre-melt arising from the use of scavenger/fluorinating agent in the pre-melt have been shown to be generally less than 10 ppb and be less than 1 ppb.

Abstract: A Hamming neural network circuit is provided with N binary inputs and M exemplar template outputs, and has a template matching calculation subnet and a winner-take-all subnet. The template matching calculation subnet includes M first neurons in which M exemplar templates are stored respectively. Each first neuron includes N pull-up and pull-down transistor pairs connected in parallel with each other, and connected to and controlled by the N binary inputs, respectively, so that the M first neurons generate M template matching signals depending on the matching degrees between the N binary inputs and the M exemplar templates. The winner-take-all subnet includes M second neurons, each having a template competition node, a load element connected between a power source and the template competition node, and a competition circuit connected between the template competition node and ground.

Abstract: A fuzzy logic recognition device has a plurality of sets of feature extraction windows, each set storing the predetermined features for one feature class therein, and comparing the stored features with the corresponding features of an unknown recognition mode to output a logic "1" via one corresponding feature extraction window where an identicalness condition occurs, and logic "0" via the other feature extraction windows where no identicalness condition occurs. A plurality of sets of membership function generators are coupled to the feature extraction window sets respectively. Each membership function generator which receives the logic "1" generates the memberships of the corresponding feature with respect to the target modes, and the membership function generators which receive the logic "0" do not generate the memberships.