A method for producing a semiconductor substrate includes the steps of: forming a first patterned mask containing a material having a growth suppressing effect on a substrate; growing a first nitride semiconductor on a portion of the substrate corresponding to an opening portion of the first patterned mask; forming a second patterned mask containing a material having a growth suppressing effect only on a main surface of the first nitride semiconductor which is positioned above the opening portion of the first patterned mask; and growing a semiconductor crystal substantially from the side surface of the first nitride semiconductor so as to form a second nitride semiconductor which integrally includes the first patterned mask and the second patterned mask.

1. Field of the Invention
The present invention relates to a method for growing, on a lower substrate, a crystal of high quality having a lattice constant different from that of a lower substrate, and a semiconductor substrate obtained by such a method. The present invention further relates to a method for growing a crystal to obtain a highly reliable device with high performance by producing a light-emitting element and an electronic element on a semiconductor substrate, and a device obtained by such a method. In particular, the present invention relates to a method for growing a crystal preferably used for producing a gallium nitride (GaN) type blue light emitting element having a high efficiency and high reliability and a light-emitting element obtained by such a method.
2. Description of the Related Art
An optoelectronic integrated circuit (OEIC) is a device which is capable of processing a large amount of information at a high speed by integrating an optical element and an Si-type LSI on the same substrate. The OEIC is expected as an indispensable device in an advanced information society and has been studied for such a reason.
In the field of an Si-type LSI, SOI, SIMOX, and the like are suggested as an ultra-fast next generation integrated circuits with low power consumption, and there is an increasing demand for technical development of SOI, SIMOX, and the like.
The main purpose in the field of an optical element is to develop a technique of producing an AlGaAs laser structure on an Si substrate. However, a difference in a lattice constant and a difference in a coefficient of thermal expansion between an AlGaAs crystal and an Si crystal of a substrate is large, thereby making it very. difficult to grow an AlGaAs crystal having good crystallinity on an Si substrate. In realizing such a semiconductor device, characteristics of an underlying crystal layer for producing a device and a substrate are important.
In particular, a gallium nitride (GaN) type semiconductor is applied to a short-wavelength light-emitting element (blue light emitting element) and an electronic element which operates at a high temperature and a high speed. In production of such a GaN type semiconductor device, a substrate made of a material (e.g., sapphire and SiC) which is different from a GaN type semiconductor is used as a substitute substrate. Basically, it is desirable to use a substrate made of GaN for a substrate on which a GaN type semiconductor crystal is grown. However, a GaN type semiconductor has a large decompression pressure, so that a large-scale bulk crystal made of a GaN type semiconductor cannot be produced; thus, such a substitute substrate is used.
In the case of using a substitute substrate as described above, a difference in a lattice constant or a difference in a coefficient of thermal expansion between a crystal of a substrate material and a GaN type semiconductor crystal is large, so that it is difficult to epitaxially grow a crystal having good crystallinity and having a small crystal defect or a crystal dislocation density on the substitute substrate. For example, in the case of using a sapphire substrate as a substitute substrate for growing a GaN semiconductor crystal, it is known that there will be a threading dislocation of about 109 to 1010/cm2 in the GaN semiconductor crystal layer grown on the sapphire substrate. Furthermore, in the case where the thickness of the GaN semiconductor crystal layer exceeds about 10 xcexcm, crystal cracks and lattice strains in the GaN semiconductor crystal layer become large.
In order to overcome the above-mentioned problems, for example, the following two methods for growing a crystal are suggested. As the first conventional example, a method for growing a crystal in Extended Abstracts 2p-Q-14, No. 1 (1997), p. 265 (The 58th Meeting, 1997); The Japan Society of Applied Physics will be described. Referring to FIG. 14, according to this method, an SiO2 pattern 901, with openings 902, is formed on a sapphire substrate 900, and then, a GaN single crystal film 903 is grown by a metal organic chemical vapor deposition (MOCVD) method, using the SiO2 pattern 901 as a mask. In the first conventional example, the growth of the GaN single crystal starts from the opening 902, not from a portion covered with the SiO2 pattern 901 of the sapphire substrate 900. Thus, strains, which are caused by a difference in a lattice constant and/or a difference in a coefficient of thermal expansion and which may cause threading dislocation, can be prevented from being generated in the vicinity of an interface between the sapphire substrate 900 and the GaN single crystal film 903. According to this method, the SiO2 pattern is effective for allowing a GaN crystal to be selectively grown (i.e., an effect of suppressing the growth of a crystal defect), so that a defect density is measured (about 105 to about 106/cm2) only in a GaN single crystal 904 above the SiO2 pattern 901 in the GaN single crystal film 903. According to this method, a value of a defect density is decreased by 4 orders of magnitude, compared with a GaN single crystal in the case where a GaN signal crystal film is directly grown on a sapphire substrate.
Furthermore, a method for growing a crystal in Extended Abstracts 2p-Q-14, No. 1 (1997), p. 266 (The 58th Meeting, 1997); The Japan Society of Applied Physics will be described. Referring to FIG. 15, according to this method, a GaN single crystal film 911 is grown on a sapphire substrate 910 by an MOCVD method, an SiO2 pattern 912 with openings 913 is formed on the GaN single crystal film 911, and a GaN single crystal film 914 is grown by an HVPE (hydride vapor phase epitaxy) method, using the SiO2 pattern 912 as a mask. According to this method, a value of a defect density of the GaN single crystal film 914 can be decreased for the same reason as that of the first conventional example. A defect density in the vicinity of the surface of the GaN single crystal film 914 is measured to be about 6xc3x97107/cm2. According to this method, a value of a defect density is decreased by three orders of magnitude, compared with a GaN single crystal in the case where a GaN single crystal film is grown directly on a sapphire substrate without using an SiO2 pattern.
A semiconductor substrate having as its surface a GaN single crystal film produced by one of the above-mentioned first and second conventional methods is used as a substrate for growing a GaN type semiconductor device, whereby it is expected to realize an electronic device with higher performance.
However, a semiconductor substrate having as its surface a GaN single crystal film obtained by using one of the above-mentioned first and second conventional methods is not sufficient for obtaining a highly reliable semiconductor laser or an LED, or electronic elements such as an FET. For example, in order to enhance a life-span of a product in a semiconductor laser device, a defect density in the vicinity of a light-emitting region is required to be about 105/cm2 or less, and a defect density is desired to be equal to or lower than the order of 104/cm2 of another III-V group (e.g., GaAs, etc.) semiconductor substrate.
A GaN single crystal layer produced by the first and second conventional methods has a defect density of about 105 to about 107/cm2, and therefore, does not satisfy the above-mentioned condition. A light-emitting element produced on a GaN single crystal layer having lattice strains and a number of crystal defects has lower reliability. For example, a semiconductor laser device produced on such a GaN single crystal layer is confirmed to have a life-span of only about 900 hours at a continuous oscillation under the condition of room temperature and an output of 3 mW.
According to the first conventional method, a high quality GaN crystal having a reduced defect density is limited to that grown in a region above an SiO2 pattern. A crystal grown in the other region has quality equal to that of a crystal according to the conventional method without using an SiO2 pattern. To use a semiconductor substrate including a GaN crystal layer having a locally reduced defect density as a substrate for growing a crystal is not practical for the reason of a limited degree of freedom of a device design.
According to the second conventional method, since an HVPE method is used, a crystal layer which is relatively thick (about several 10 xcexcm) for an epitaxial growth film can be obtained. The effect of the SiO2 pattern is relaxed in the vicinity of the surface of the GaN crystal layer by increasing the thickness of the crystal layer, so that defects will be uniformly distributed in the entire surface. Accordingly, the problem that crystal quality of the GaN crystal layer is locally improved as in the first conventional example can be solved. However, in terms of the defect density, the second conventional example is inferior to the first conventional example.
In addition, according to the first and second conventional methods, a GaN single crystal layer is produced by using an SiO2 pattern in the shape of a stripe. Thus, lattice strains are decreased in a direction vertical to the stripe of the SiO2 pattern; however, lattice strains in a plane parallel to the stripe remain substantially equal to that of a crystal according to the conventional method without using an SiO2 pattern. When a GaN type semiconductor layer is grown on a GaN crystal layer in which lattice strains having a particular directivity are introduced, lattice strains having anisotropy are propagated to the GaN type semiconductor layer.
Alternatively, it is also possible to grow a thicker GaN crystal layer (about 50 xcexcm) on a sapphire substrate, and remove the sapphire substrate from the reverse surface of the GaN crystal layer, thereby obtaining a GaN substrate. However, crystal defects (more than on the order of 105/cm2) remain even in the GaN substrate thus obtained, and lattice strains having anisotropy cannot be relaxed.
A method for producing a semiconductor substrate of the present invention, includes the steps: forming a first patterned mask containing a material having a growth suppressing effect on a lower substrate; growing a semiconductor crystal on the lower substrate via the first patterned mask to form a first semiconductor crystal layer; forming a second patterned mask containing a material having a growth suppressing effect on or above the lower substrate, the second patterned mask at least having a surface which is positioned at a level different from a level of a surface of the first patterned mask, with respect to a surface of the lower substrate; and growing a semiconductor crystal on or above the lower substrate via the second patterned mask to form a second semiconductor crystal layer.
In one embodiment of the present invention, the second patterned mask is positioned on the first semiconductor crystal layer.
In another embodiment of the present invention, the first and second patterned masks are patterned in such a manner that a combination of the first and second patterned masks covers the entire surface of the lower substrate, and an area of the lower substrate covered with the second patterned mask is larger than an area of the lower substrate covered with the first patterned mask.
In another embodiment of the present invention, the second patterned mask includes a first portion and a second portion, the first and second portions have different widths in a direction vertical to the surface of the lower substrate, and the step of forming the first semiconductor crystal layer and the step of forming the second semiconductor crystal layer are conducted during the same crystal growth step.
In another embodiment of the present invention, the first portion of the second patterned mask is at least partially positioned on the first patterned mask, and the second patterned mask has an L-shape.
In another embodiment of the present invention, the first portion of the second patterned mask is at least partially positioned on the lower substrate, and the second patterned mask has a T-shape.
In another embodiment of the present invention, a growth direction of the second semiconductor crystal layer is at least partially different from a growth direction of the first semiconductor crystal layer.
In another embodiment of the present invention, the first semiconductor crystal layer is formed in the vicinity of openings in the first patterned mask, whereby the first semiconductor crystal layer has openings on the lower substrate and the first patterned mask.
In another embodiment of the present invention, the lower substrate includes a sapphire substrate and a lower semiconductor crystal layer provided on an upper side of the sapphire substrate in a crystal growth direction.
In another embodiment of the present invention, the material having a growth suppressing effect is selected from the group consisting of SiO2 and SiNx, and the first and second patterned masks are independently selected from the group consisting of SiO2 and SiNx.
In another embodiment of the present invention, the first and second semiconductor crystal layers are selected from the group consisting of GaN, InGaN, and AlGaN.
A semiconductor substrate of the present invention, includes: a first patterned mask containing a material having a growth suppressing effect, provided on a lower substrate; a first semiconductor crystal layer grown on the lower substrate via the first patterned mask; a second patterned mask containing a material having a growth suppressing effect, provided on or above the lower substrate, at least having a surface which is positioned at a level different from a level of a surface of the first patterned mask, with respect to a surface of the lower substrate; and a second semiconductor crystal layer grown on or above the lower substrate via the second patterned mask.
A method for producing a semiconductor substrate of the present invention, includes the steps of: forming an n-th patterned mask containing a material having a growth suppressing effect on or above a lower substrate, wherein n is an integer of 1 or more: growing a nitride semiconductor crystal on or above the lower substrate via the n-th patterned mask to form an n-th nitride semiconductor crystal layer; forming an (n+1)-th patterned mask containing a material having a growth suppressing effect on or above the lower substrate, the (n+1)-th patterned mask at least having a surface which is positioned at a level different from a level of a surface of the n-th patterned mask, with respect to a surface of the lower substrate; and growing a nitride semiconductor crystal on or above the lower substrate via the (n+1)-th patterned mask to form an (n+1)-th nitride semiconductor crystal layer.
In one embodiment of the present invention, the first to (n+1)-th patterned masks are patterned in such a manner that a combination of the first to (n+1)-th patterned masks covers the entire surface of the lower substrate.
In another embodiment of the present invention, the n-th patterned mask and the (n+1)-th patterned mask are respectively patterned in a stripe shape, and a direction of the stripe of the n-th patterned mask is twisted from a direction of the stripe of the (n+1)-th patterned mask.
In another embodiment of the present invention, the direction of the stripe of the n-th patterned mask and the direction of the stripe of the (n+1)-th patterned mask have an angle difference of about 120xc2x0.
In another embodiment of the present invention, the direction of the stripe of the n-th patterned mask and the direction of the stripe of the (n+1)-th patterned mask have an angle difference of about 90xc2x0.
In another embodiment of the present invention, a width of the stripe of the (n+1)-th patterned mask is equal to or larger than a width of the stripe of the n-th patterned mask.
In another embodiment of the present invention, the material having a growth suppressing effect is made of SiO2 or SiNx, and the first to (n+1)-th patterned masks are independently made of SiO2 or SiNx.
In another embodiment of the present invention, the lower substrate includes at least a lower nitride semiconductor crystal layer provided on an upper surface of the lower substrate, and a direction of the stripe of the n-th patterned mask is equal to a  less than 1-100 greater than  direction or a  less than 11-20 greater than  direction of a crystal of the nitride semiconductor crystal layer.
In another embodiment of the present invention, the lower substrate includes at least a lower nitride semiconductor crystal layer provided on an upper side of the lower substrate in a crystal growth direction, the semiconductor substrate includes the first, second and third nitride semiconductor crystal layers, and a combination of directions of the first, second and third patterned masks consists of a combination of [1-100], [10xe2x80x9410], and [01-10] directions of a crystal of the nitride semiconductor crystal.
In another embodiment of the present invention, the n-th nitride semiconductor crystal layer is made of AlxInyGazN (where x+y+z=1, 0xe2x89xa6Xxe2x89xa61, 0xe2x89xa6yxe2x89xa61, and 0xe2x89xa6zxe2x89xa61).
In another embodiment of the present invention, the n-th nitride semiconductor crystal layer or the (n+1)-th nitride semiconductor crystal layer has a thickness of about 5 xcexcm or more.
In another embodiment of the present invention, the lower substrate includes a substrate body and a lower nitride semiconductor crystal layer provided on an upper side of the substrate body in a crystal growth direction, the method further including the step of removing at least the substrate body from a crystal structure including the (n+1)-th nitride semiconductor crystal layer after the step of forming the (n+1)-th nitride semiconductor crystal layer.
A semiconductor substrate of the present invention, includes: an n-th patterned mask containing a material having a growth suppressing effect provided on or above a lower substrate, wherein n is an integer of 1 or more; an n-th nitride semiconductor crystal layer grown on or above the lower substrate via the n-th mask; an (n+1)-th patterned mask containing a material having a growth suppressing material provided on or above the lower substrate, the (n+1)-th mask at least having a surface which is positioned at a level different from a level of a surface of the n-th mask, with respect to a surface of the lower substrate; and an (n+1)-th nitride semiconductor crystal layer grown on or above the lower substrate via the (n+1)-th patterned mask.
A light-emitting device produced by using the above-mentioned semiconductor substrate is provided.
Thus, the invention described herein makes possible the advantages of (1) providing a semiconductor substrate including a nitride semiconductor crystal layer with a crystal defect density and a threading dislocation surface density sufficiently reduced, and a method for producing the same; (2) providing a semiconductor substrate including a nitride semiconductor crystal layer with no lattice strains having anisotropy introduced thereto, and a method for producing the same; and (3) providing a highly reliable semiconductor device with high performance, using a semiconductor substrate including a nitride semiconductor crystal layer with improved crystallinity as a substrate for growth, and a method for producing the same.
These and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures.

Method for producing a semiconductor substrate


A photo-ionization detector having an adjustable drive power for a UV lamp implements a calibration operation that determines measurement signals for a series of drive power levels and based on the resulting measurement signals selects one or more drive power levels for normal operation of the PID. The calibration operation permits use of UV lamps having a wider range of performance levels and thereby improves manufacturing yields and extends the useful life of the PID. During normal operation, the PID further fine-tunes the drive power level to compensate for expected or measured degradation in lamp performance. Accordingly, between calibrations, the PID maintains a more uniform UV intensity for more accurate measurements. To expand the measurement range of the PID, the calibration process can select two or more power levels for use when measuring different gas concentrations.

Photo-ionization detectors (PIDs) can detect and measure the concentrations of volatile gases in a gas sample by ionizing the volatile gases and measuring a resulting ionization current. FIG. 1 illustrates a conventional PID 100 including an ultraviolet (UV) lamp 110, which typically produces high-energy photons having energy above about 8.4 electron volts (eV). The high-energy photons from UV lamp 110 are directed into an ionization chamber 120 through an optical window 116, which may be an integral part of UV lamp 110. When a UV photon collides with a volatile gas molecule having an ionization potential below the energy of the UV photon, the collision ionizes the volatile gas molecule freeing an electron and creating a detectable ion.
An ion detector 130 in PID 100 has a pair of electrodes 132 and 134 that are typically made of a metal. A high voltage (e.g., greater than 150 V) applied between electrodes 132 and 134 generates an electrical field that attracts positively-charged particles (e.g., ions) to electrode 132 and attracts negatively-charged particles (e.g., electrons) to electrode 134. Electrode 134 repels ions towards electrode 132 that is simultaneously collecting the volatile gas ions. As a result, a measurement current produced at electrode 132 indicates the number of ions collected. The magnitude of the measurement current (or a measurement signal generated from the measurement current) therefore depends on the concentration of ionizable gas molecules, the intensity of the UV light in ionization chamber 120, and the efficiency of ion detector 130. If the detector efficiency and the UV light intensity are constant, a one-to-one mapping can be used to convert the measurement signal to a concentration, e.g., in parts per million (ppm) of the volatile/organic compounds.
A conventional PID 100 has a drive circuit 112 that drives UV lamp 110 with a constant amplitude driver signal. However, with a constant driver signal, a variety of factors, including degradation of UV lamp 10, contamination of optical window 116, and the presence of interfering substances such as methane in ionization chamber 120 typically diminish the UV light intensity of UV lamp 110 during normal operation of PID 100.
U.S. Pat. No. 6,225,633 issued to Hong T. Sun and Peter C. Hsi describes a process for self-cleaning a PID and particularly the optical window in the ionization chamber. The self-cleaning process traps air or another gas containing oxygen in the ionization chamber and transmits UV light into the ionization chamber to create ozone. Circulation through the PID is restricted so that the ozone accumulates in the ionization chamber, and ozone, being a strong oxidant, etches and removes the contamination from the optical window and other surfaces in the ionization chamber. Although the cleaning of the window eliminates or reduces one cause of UV intensity reductions, the degradation of the UV lamp still causes the gradual loss of UV light intensity. As a result, the measurement current that a conventional PID detects for a specific gas concentration decreases over time.
FIG. 2 illustrates plots 210, 220, 230, 240, and 250 of the typical dependence of the measurement signal on the volatile gas concentration for several different UV intensities. A calibration operation for a conventional PI) feeds a span gas having a known concentration of volatile gases into the PID, activates the UV lamp, and selects the mapping 210, 220, 230, 240, or 250 that maps the resulting measurement signal to the known concentration of the span gas. The mapping selected during calibration is then used for measurements during normal operation. However, as a PID ages, the UV intensity from the lamp drops, and the selected mapping of the measurement signal to the gas concentration becomes inaccurate. To prevent drift in the concentration measurements, a conventional PID thus requires frequent calibration to reselect the correct mapping for the conversion of measurement signals to volatile gas concentrations.

Automatic drive adjustment of ultraviolet lamps in photo-ionization detectors


Disclosed is a vaccine for the prevention of disease caused by canine distemper virus (CDV). The vaccine is prepared from CDV immunogens derived from CDV persistently-infected cells cultured in vitro. CCL-64 mink lung cells are the preferred cell line. CDV persistently-infected cells are cultured in serum-containing growth medium, the cells transferred and maintained in serum-free medium under conditions and for a time adequate to accumulate in said serum-free medium said CDV immunogens, and the cells separated from said CDV immunogen-containing supernatant. The CDV vaccine is made by diluting said supernatent and blending with a pharmaceutically-acceptable adjuvant.

Canine distemper virus (CDV) belongs to the family Paramyxoviridae within the genus Morbillivirus. CDV is an enveloped single-stranded RNA virus of about 100-300 nm in diameter. The CDV virion core contains a nucleoprotein (NP) peptide that closely associated with viral RNA. A second core peptide is a phenophorylase (P). The CDV envelope contains three peptides, M protein (matrix protein) and two glycoproteins. The glycoproteins are the hemagglutinin glycoproteins (H) and a fusion (F) glycoprotein. The fusion glycoprotein is degraded into smaller sub-units designated F.sub.1 and F.sub.2. The H protein is responsible for viral adsorption to target cells and the fusion glycoprotein is responsible for the cell-to-cell fusion. As far as is known, all distemper virus isolates contain these common viral polypeptides. The route of infection to the dog is by infective aerosol droplets. Transmission of the virus is facilitated by coughing and sneezing and close confinement in a warm, humid, closed environment. Studies suggest that viral infection occurs first in the respiratory epithelium of the upper oronasal tract with subsequent spread to the deep pulmonary parenchyma. Gorham "Canine Distemper", Advance Veterinary Science, Brandley and Jungher Editors, 6:288- 315 (1960).
Tissue macrophages and monocytes located in or along respiratory epithelium in tonsils appear to be the first cell type to pick up and replicate CDV. The virus then is spread by lymphatics in blood to distant lymphoreticular tissues. This is accomplished by viremia and occurs anywhere from two to four days after initial infection. Between eight and nine days after infection, the virus spreads beyond lymphoreticular tissues to involve epithelial and mesenchymal tissues. Appel, "Pathogenesis of Canine Distemper", The Am. J. Vet. Res., 30:1167-1182 (1969). This probably occurs in every animal regardless of the outcome of the disease process. It is at this stage of the virus infection that specific host immune responses to viral antigens influence the outcome of disease. The acute fatal form of the disease is characterized by unrestricted viral spread to virtually every tissue in the body. Virus is found in every excretion and secretion and, by using immunofluorescence methods or antigen tracing techniques, antigen can be demonstrated in virtually every cell type within the dog. For most of these animals, the most likely cause of death is fulminant fatal neurologic involvement.
Some CDV infected dogs exhibit clinically delayed progression of disease and modest convalescent immune responses. Clinical signs, if present, are subtle early in the disease and are a reflection of viral persistence within the central nervous system (CNS). Subsequent development over CNS disease is variable. Most CDV infected dogs exhibit essentially no overt clinical signs of disease and are recognized as convalescent, clinically normal dogs. Actively infected dogs destined to recover from CDV infection will demonstrate free circulating anti-viral antibodies on or about post infection day six or seven. Krakowka, et al., "Serologic Response to Canine Distemper Viral Antigens in Gnotobiotic Dogs Infected with R-252 Canine Distemper Virus", J. Infect. Dis., 132:384-392 (1975). Titers rise rapidly to high levels in early convalescence.
Dogs affected acutely with CDV show variable degrees of depression, anorexia, and fever. The skin may be variably dehydrated, dry-roughened, and inelastic. A proportion of these animals will show photophobia and some will have evidence of mucopurulent ocular-nasal discharge. Intermittent diarrhea is a common clinical sign. During this acute viremic phase of the disease, virus is shed in every secretion and excretion. As the disease progresses, pneumonia, frequently due to secondary bacterial invaders, may develop. Dogs in this stage of disease are moderately to severely lymphopenic. They frequently exhibit a coincidental leukocytosis and left shift, depending on the degree or amount of secondary infection.
Although acutely affected dogs can show virtually every combination of neurological signs, in its most common presentation a dog presents petit mal or grand mal siezures. These convulsive episodes occur over time and with increasing frequency.
The second neurologic form of canine distemper is that which occurs with old dog encephalitis (ODE), or occurs after sub-clinical infection and apparent recovery. The CNS signs can be extremely varied in presentation and can be mistaken for brain tumor, head trauma, bacterial menengitis, hydrocephalus, and spinal cord disk disease. A major non-neural manifestation of CDV infection in dogs is CDV-associated immunodepression. Krakowka, et al., "Canine Distemper Virus: A Review of Structural and Functional Modulations in Lymphoid Tissues", Am. J. Vet. Res., 41:284-292 (1980). Many of the signs of canine distemper virus infection are attributable to coincidental secondary infectious processes occurring in this debilitated animal.
The chief and most important bacterial pathogens associated with disease in dogs are the pneumonic bacterial species including: Bordetella bronchiseptica, Pasteurella spp., and of course, Staphylococcus and Streptococcus spp. These agents are responsible for the purulent conjuctivitus, rhinitis, and bronchopneumonia noted clinically in CDV-infected dogs. Mixed viral infections, chiefly of the respiratory type, also are common. In addition to canine adenovirus II infection, reovirus, canine parainfluenza virus, and presumably other viruses such as canine herpes virus, are all involved in this dual or multiple mixed infection problem.
As a consequence of direct CDV infection either in lymphoid cells and/or macrophages, lymphocytes from CDV-infected dogs are rendered incapable of generating effective in vitro and in vivo immune responses. The early virolytic effects of CDV upon the lymphoid system and macrophages also has the effect of suppressing established immune responses and/or normal host defenses.
There exists a number of safe and efficacious, modified-live viral vaccine products. The virus, consisting chiefly of laboratory adapted and attenuated Rockborn or Lederle strains of CDV, is propagated in canine origin continuous cell lines. One innoculation into the CDV-susceptible clinically healthy, normal dog, will provide effective and probably lifelong immunity. Thus, under typical clinical circumstances, immunity can be assured by delivering the product according to manufacturer's instructions to the animal or animals in question. There are, however, a number of different exceptions to this generality that should be mentioned. For example, the use of modified-live CDV vaccine in exotic animal species should be avoided. Montali, et al., "Clinical Trials with Canine Distemper Vaccines in Exotic Carnivores", J. Am. Vet. Med. Assoc., 183:1163-1167 (1983). Some exotics such as the lesser panda and black-footed ferret are highly susceptible to CDV and have been killed with modified-live (MLV) CDV vaccine. Even species within the Canidae family may show heightened susceptibility to CDV. For example, MLV-CDV was recently shown to be dangerous for use in grey foxes but not in red foxes. Halbrooks, et al, "Response of Grey Foxes to Modified-live Virus Canine Distemper Vaccines", J. Am. Vet. Med. Assoc., 179:1170-1174 (1981).
The final precaution relates to the clinical interaction of canine parvovirus infection with canine distemper virus infection. On a clinical basis, it has been noticed that canine parvovirus infection potentiates the lethal effects of either concurrent CDV infection or CDV fatalities associated with vaccination with an ordinarily safe modified-live product. Though this is a clinical association, it is known that dogs actively infected with virulent canine parvovirus are at risk for developing fatal CDV-vaccine associated neurologic disease. Krakowka, et al, "Canine Parvovirus Infection Potentiates Canine Distemper Encephalitis due to Modified-live Virus Vaccine", J. Am. Vet. Res. Assoc., 180:137-139 (1982).
Thus, there is a current need for an efficacious non-infective CDV vaccine product that can be used in combination with the ML-CPV vaccine. It is to such a vaccine that the present invention is directed.

Canine distemper virus vaccine and method of preparation


A software-based syndication and filtering platform for a first Web server hosted by a first enterprise has a rules-based filter for interacting with communications from customers of the first enterprise, the communications coming from a second Web-site of a second enterprise, and a discrimination layer for providing specific services to said customers according to one or more characteristics of the Web site of the second enterprise. In some cases there is also a layer for interacting with a third Web server hosted by a third enterprise. In preferred embodiments the services include a broad range of transaction capabilities.

Through a number of techniques and computer architecture, much of which is subject matter of other patent applications, Yodlee.com, Inc., the 100% owner of the present patent application, currently aggregates end user account data for normalization and presentation to end users through a growing syndicate of destination sites as described in greater detail below. As of this writing, on behalf of end users, Yodlee.com maintains a large number of aggregated accounts from many service providers in the bank, brokerage, credit card, reward program, bills and email verticals. FIGS. 12 through 16 in this application illustrate a novel improvement to current account aggregation technology—an e-Finance Transactions Network (ETN). FIGS. 12-16 in conjunction with detailed description herein provide a detailed description of this invention.
Currently account aggregation is often effected through a procedure known colloquially as "screen scraping." Internet Protocol and XML, among other procedures, enables Yodlee.com to harvest information of relevance to the end user. The Yodlee.com service is designed in part to keep the information provider engaged with its customer (for example, the service takes customers back to the information provider's site to allow the customer to transact in his account). the present inventors, however, have invented a solution that will improve upon the screen scraping-only model of aggregation by affording an even greater amount of engagement for the information provider with its customer and for the other reasons set forth below.
e-FINANCE TRANSACTION Network
Yodlee.com, according to embodiments of the present invention described in enabling detail below, has devised a novel improvement to existing account aggregation and Internet transactions that will (i) allow financial institutions to syndicate more effectively their Web strategies and transactional capabilities and (ii) place control over the customer relationship completely in the hands of the financial institutions or other information provider.
The Internet technology paradigm of almost every financial institution today is three-tiered architecture through which the institution provides financial services to its customers. The first tier is a series of back-end host or legacy systems containing customer data. The second tier is a "business logic," "rules" or "applications" layer that contains the rules that allow certain kinds of transactions to occur. For example, if a customer seeks to obtain a mortgage, the institution's business logic, using the repository of data contained in the host system, evaluates the creditworthiness of the applicant and renders a credit decision to issue or deny the loan. The third tier is represented by a Web server that permits the institution to publish the results of this process on the Web through Web servers provided by a number of hardware suppliers. The common denominator in virtually all of these implementations is the last link in the chain, the Web server connecting the institution to its customer on the Internet (whether the customer is accessing the system through a personal computer, set-top box, wireless device or some other means).
A financial institution's second tier, its business logic, may be the most valuable unexploited asset in terms of this architecture. The essence of the institution's business (issuing loans or credit cards, opening checking, savings or brokerage accounts, managing the transfer of money or the purchase of a security) is achieved through this layer of the institution's infrastructure. Due to the institutions' concern about diluting the power of their brands, many institutions have sought to "protect" this asset by exposing it to its customers on the Internet only through the institution's own Web site. Thus, the institution makes its core products available only at its own URL—a "geography-based" availability that limits the institution's ability to leverage its core technology and the customer's ability to engage in meaningful transactions with the institution from a site other than the institution's own. Today's environment is such that customers may not even consider seeking to access their checking account from a popular Internet site (such as Yahoo! or AOL) that the customer would otherwise consider his or her "home base" on the Internet.
Notwithstanding the geography-based environment imposed by the institutions due to branding concerns, the technological reality underlying the institutions' business logic layer is identity-based. That is, the institution's logic associates the customer with his or her accounts. Given customers' desire to access these identity-based accounts to from media channels such as Yahoo! and AOL, a number of businesses have emerged that seek to emulate or replicate the customer experience by technologies such as screen scraping so that a user can gain access to his or her identity-based data in the institution's host system from a site other than that of the institution. But these emulation experiences are "stateless" in terms of their interaction with the institution's business logic layer, which means they have limited utility to the customer and to the institution. From the institution's perspective, the absence of a "stateful" session with the institution's business logic means that the institution knows nothing about what the customer has done with the data and has no audit trail with respect to what action (if any) the customer experience may have produced on the customer's underlying accounts.
The present inventors have invented a provider-side syndication and filtering platform that will be delivered to providers as a software development kit ("SDK") or other suitable implementation format made available to any provider desiring to control its customers' remote interactions online. This SDK will be identity- and geography-based, rather than being only geography-based, thereby enabling a user to access his or her bank account from a site other than the bank's, but still interact in a stateful session with the business logic of the bank. This unique platform consists of a rules-based filter developed preferably as a servlet, but other embodiments may utilize other commonly known server extension technologies, allowing customers varying levels of access and transactional capability depending on a number of variables, such as who the user is, and from where the user accesses the account from the Web. The platform will accomplish the task of enabling customers to view their information and transact with the provider by defining a normalized set of services, or API's that are common to providers of a category. For example in the financial services industry, a list of services could include "1. Create new account," "2. Authenticate customer," "3. Retrieve summary balance information," "4. Retrieve detailed transactions," "5. Initiate funds transfer from Account A to destination B." The SDK will allow providers to tell the servlet how to fulfill those services in their own environment and the servlet will communicate with ETN the results or confirmations of fulfilled services. Other industries, such as travel, will have their own subset of normalized services. Mileage programs for example could include services such as, "1. Create new account," "2. Authenticate customer," "3. Retrieve summary balance information," "4. Retrieve detailed transactions," "5. Get list of eligible rewards," "6. Redeem mileage points from Account A for reward B." Other industries may have analogous schemas.
The platform in some embodiments will utilize powerful internal and external directory services developed by leading computer networking vendors. It is expected that the filtering layer would ship with each Web server distributed by such a supplier supplier or downloadable via the Internet. Combined with Yodlee.com's unique positioning in the financial institution marketplace, this approach would allow the company to rapidly seed the market for this technology. The solution is referred to herein as an "e-Finance Transaction Network" or (ETN).
The ETN has several important effects from the perspective of the financial services provider. First, as noted above, since the platform will be identity-based as well as geography-based, it allows the provider institution to give users different degrees of data and transacting capability depending upon the site from which the user accesses the institution. Through the rules embedded in the filtering platform, the institution is able, for example, to give the user (i) full access to the user's account (including full transactional capability) if the user accesses the account through the institution's own site, (ii) somewhat less data and transactional capability if the user accesses the institution from, for example, a non-affiliated Web portal, (iii) less data and less transactional capability still if the user accesses the institution from a competitive money management site and (iv) very limited and/or no data and access if the user accesses the account from a competitive banking property. The ETN effectively allows the provider institution to gain significant control of the customer's remote Web experience.
Second, the ETN will give the financial institutions a far more effective vehicle for syndicating (i) their online strategies and (ii) their significant investment in the all-important business logic layer of their technology infrastructure. Financial Institutions are increasingly aware that online banking or brokerage services alone are not sufficient to maintain a meaningful share of attention from a large percentage of their customers. Such institutions need an effective transaction syndication vehicle to touch a high percentage of their customers who are not presently engaging with the institution at its own Web site.
Third, the ETN will promote a level of financial standardization and customer convenience that is as yet unrecognized among Web properties. The ETN, because it will be embedded in a substantial number of Web servers or readily accessible via the Web, will permit fully integrated "drag and drop" transactions to be conducted through a friendly graphical user interface on a client computer. For example, it will be possible to purchase merchandise or pay a bill online by dragging currency from an online accessible checking account to an online retailer or bill presenter. The communication between the bank and either the retailer or bill presenter will be transparent to the user.
Fourth, unlike the situation now existing with account aggregation, the platform will permit the provider institution to maintain a direct marketing relationship with its customer, knowing, for example, what types of activities the customer is conducting at the institution when the institution is accessed from a destination site other than the institution itself. This arrangement will be both more reliable (in terms of data integrity) and more auditable than any known current forms of account aggregation. Rather than losing control of the customer information path when information is taken away from the institution, through the existence of a stateful session with the business logic layer, the ETN will allow the institution to remain in the information flow, which is valuable in and of itself to the institution.
It is important to note that application of the ETN extends beyond interactions with personal computers alone. The types of information and transactions that the ETN will permit will be accessible from cellular phones, personal digital assistants and other wireless devices, through integrated voice response systems, on set-top boxes or any other kind of digitally-enabled device. It is also important to note that the application of the ETN may be extended beyond the financial vertical alone. For example, the technology resulting from the development of the ETN could be applied to enable the buyer of an automobile from Ford Motor Company to check the status of delivery of the automobile or purchase a 100,000-mile warranty package from Ford Motor Credit Company by interacting with Ford's legacy technology system through an Internet site such as Yahoo!.
Given the somewhat stateless nature of screen scraping, the inventors believe that financial institutions will be very receptive to this proposition, and will desire to regain control of the customer experience through access to the ETN. From a technology partner's perspective, this mechanism will give the technology partner an opportunity to participate in the recurring revenue stream available from financial transactions, rather than simply publishing data from financial institutions on the Web through its server network.
The concept for the ETN is born of both real and perceived shortcomings of screen scraping. The ETN may eventually obviate the need for any sort of widespread screen scraping of information providers, because information will be provided directly to the ETN (subject to the permission levels described above) by the information providers. For information providers that choose not to subscribe to the ETN, Yodlee.com will continue to offer aggregated information collected through its proprietary screen scraping technology, also described below.
Information on Scraping Technology
Looking back, it is apparent that as the Internet has gained momentum, consumers have demanded applications or services that make their online experience simpler, easier to use, and more satisfying. The development of successful Internet sites has typically corresponded with a number of themes which have developed over the last few years. When carefully analyzed, this evolution is a logical development of the emerging digital economy.
Prior to 1994 the Internet was not a mass media, in part because the existing technologies (such as FTP, Archie, Usenet, and Gopher) were not user friendly and required the end user to do all of the work (e.g., the end user had to learn of an existing data source, find the address, navigate to the destination, and download the information). As more consumers began accessing the Internet, Search Engines were created to solve this usability issue. With the advent of the commercial Search Engine, additional content could be easily added to the Internet and the end user had a means of finding and accessing this information. But consumers required better tools than Search Engines for organizing and accessing this wealth of generic content. Push technologies were explored, and eventually, the portal strategy was successfully adopted as an efficient way for consumers to easily access a variety of content sources in a single, easy to use format. As the volume of available online content continues to grow exponentially, portals are now confronted with the need to make different types of content available to different consumers based upon their particular preferences and tastes.
The phenomenal success of Internet portals and destination sites has demonstrated the importance of creatively and intelligently aggregating, organizing and presenting the mass of information available on the Web. Search engines, portals and destination sites have Internet strategies based on the frequency, duration and quality of end user visits to their sites. For this reason, destination sites and portals are constantly seeking content and/or technologies which drive quality traffic to their sites and keep it there. Recent trends indicate that Internet users are up to 25 times more likely to come back to a site when this information is organized according to personal preferences.
FIG. 1 displays the current process of acquiring online PI 100. The end user first selects an information provider site in step 110. The end user proceeds to step 120 by locating and entering the Internet address of the selected information provider. This step may be accomplished in several manners with varying levels of complexity. A simple means for accomplishing this step is the utilization of a bookmark or favorite whereas locating an information provider for the first time might involve significant time and effort performing online searches. In step 130, the end users logs into the selected information provider's Web site utilizing the site's specific logon protocol. This protocol usually involves verifying the identity of the end user using a user name and password or other means of verification, acquiring the verification data from cookies residing on the end user's system or a combination of requested data and cookie data. The end user continues in step 140 by navigating through Web pages on the information provider's Web site until the desired information is located. During this process, the end user is often required to visit Web pages of little or no use to the end user whose goals is to simply acquire the particular PI residing on the Web site. Ultimately in step 150, the end user is presented with the desired PI. The entire process 100 is repeated for each individual piece of PI desired by the end user. Under this PI access model, the end user must visit each separate information provider, track potentially different identity verification data for each, utilize a different user interface at each site and possibly wade through a significant number of filler Web pages.
FIG. 4 pictorial illustrates the architecture of this current access process. The end user 210 utilizes the client computer 220 to access each PI Web site 250 across the Internet 230. This current model suffers from several significant deficiencies. The end user must login to each site separately. Each separate site has its own graphical user interface. Each site wants the end user to stay and return; each visited site wants to retain end user focus for as long as possible. No true aggregation of PI exists; multiple accesses simply allow sequential access to particular pieces of PI.
One partial solution to these problems has recently evolved in the form of portal sites. Generic portal sites aggregate resources into categories and provide links to sites covering topics within those categories. Yahoo and Excite are examples of generic portal sites. These sites facilitate horizontal aggregation of generic content; horizontal aggregation refers to aggregation of PI access within a particular information provider category such as banks or utility companies. Some portal sites allow individual end users a limited capability to select and configure disparate generic PI. Generic PI refers to PI of interest to the particular end user that does not require specific identity verification to obtain. For example, an end user might be interested in the weather forecast for his local area. This information could be integrated into a portal page without requiring identity verification of the particular end user receiving this PI. The individualized portal page provides a significant benefit to users seeking to aggregate generic PI. However, current portal pages do not generally provide PI requiring identity verification such as an end user's stock portfolio or bank balance. Further, these pages do not facilitate transactions utilizing PI.
Under current technology, aggregating PI available over the Internet requires a significant burden in terms of time, effort and learning curve. An end user wishing to access his PI needs to individually visit a variety of information provider sites each with its own requirements, graphical user interface and login protocol.

System and method for syndicated transactions


A handheld oscillation applicator (40) for use in a magnetic resonance rheology imaging system (10), for applying mechanical oscillations to at least a portion of a subject of interest (20), the handheld oscillation applicator (40) comprising a housing (54), at least one transducer unit (48) configured to output mechanical energy, a piston (68) that is mechanically linked to the at least one transducer unit (48), the piston (68) including a first end (70), a second end (72), and an opening (74) that extends between the first end (70) and the second end (72), wherein the housing (54) comprises at least one opening (60), and the at least one opening (60) of the housing (54) and the opening (74) of the piston (68) at least partially overlap with regard to a housing opening direction (66) defined by an opening center (62) of the opening (60) of the housing (54) at a first surface (56) and an opening center (64) of the opening (60) of the housing (54) at a second surface (58); and an oscillation applicator system (38), including: a handheld oscillation applicator (40), a transducer driving unit (42) for energizing the at least one transducer unit (48), a sensing unit (50) configured to determine a physical quantity that is representative of an amplitude of mechanical oscillations being applied to at least the portion of the subject of interest (20), and to provide an output signal representing the determined physical quantity, at least one closed-loop control circuit for maintaining a mechanical displacement amplitude of the transducer unit (48) at a selected level, wherein the closed-loop control circuit is configured to provide an output signal for controlling the transducer driving unit (42), based on the output signal received from the sensing unit (50).

In the art of magnetic resonance imaging, it is known to characterize mechanical properties of human or animal tissue by magnetic resonance rheology (cf. for instance to Muthipillai R. et al., Magnetic resonance imaging of acoustic strain waves, Proc. Soc. Magn. Reson. Nice, 1:189, 1995). In magnetic resonance rheology, the tissue is driven to mechanically oscillate during magnetic resonance imaging, which leads to effects causing an imaging contrast due to differences in tissue viscosity or elasticity. Low-frequency mechanical waves are coupled into the tissue and are visualized via a magnetic resonance sequence. The obtained additional information can be used, for instance, to distinguish healthy from malign tissue.
A number of different mechanical transducers for applying the mechanical oscillations to the tissue have been proposed, such as electromagnetic designs, which make use of the main magnetic field B0 inside the magnetic resonance scanner. Further, piezo-driven transducers or pneumatic designs were proposed for clinical application. In general, any mechanical transducer that appears to be suitable to the one skilled in the art may be employed.
Conventionally, magnetic resonance rheology examinations are carried out with a mechanical transducer that is statically attached to a subject of interest, for instance by strapping it around the subject of interest, or such that the subject of interest is lying on the mechanical transducer. An example of a conventional oscillation applicator for use in magnetic resonance rheology is shown in FIG. 5. The conventional oscillation applicator comprises a housing 96, which encompasses a mechanical transducer, and a piston 98 that is provided for transferring mechanical oscillations to the subject of interest. Dimensions of conventional oscillation applicators are about 50 millimeters in height with a footprint of about 100×100 mm2.
Further, the paper 'MR elastography of the head and neck: Driver design and initial results' by D. K. W. Yeung in Magn.Res.Imag. 31(2013)624-629 discloses a driver for MR elastography. This known driver comprises a tranducer embedded in a foam slab. The transducer has a protruding piston and a coil mounted at one of the piston. A headrest mould is positioned over the transducer and an opening opposing the centre of the piston is cut from the mould.

Handheld oscillation applicator for use in a magnetic resonance rheology imaging system


The addition of copper phthalocyanine to composite solid propellant compositions has been found to substantially reduce the tendency toward combustion instability of the propellant. The invention is particularly useful in connection with smokeless composite propellants employing hydroxy-terminated polybutadiene as a binder.

Combustion instability in a composite solid propellant rocket motor is a phenomenon which can be considered to be occurring when the actual chamber pressure observed in the rocket motor exceeds, while operating in the manner intended, the chamber pressure for which the motor was designed, based on propellant burn-rate data obtained from small motor or strand-burning tests. Combustion instability can be characterized either by (a) acoustic oscillations in the chamber pressure which may continue for a portion or all of the burn time of the motor and ususally at a mean pressure higher than that predicted for normal operations or (b) a sudden rapid rise in the chamber pressure which can cause catastrophic failure of the motor. In those cases in which a catastrophic failure of the rocket motor does not occur as a result of the instability, it is still an undesirable phenomenon since most solid propellants are targeted, or their operation predicted, on a knowledge of the pressure-time trace of the rocket motor which directly affects the thrust produced. If the actual chamber pressure is higher than that for which the motor is designed, the motor cannot be used to provide the desired performance with acceptable reliability since predictable ballistic performance depends on a predictable thrust vs. time curve which, in turn, depends on a predictable pressure vs. time program.
Various factors affect combustion instability, and, in general, combustion instability is more likely to occur when rocket motors (a) are operated at higher chamber pressures (b) have greater lengths or length to diameter ratios (c) employ propellants having high solid loadings of oxidizers or (d) are operated at elevated grain temperatures. Various approaches have been taken in the past to solve the problems of combustion instability. These approaches have included the use of resonance rods, the use of exotic grain designs, the use of mass addition techniques to upset the circulation pattern within the combustion chamber, the use of additives such as those disclosed in U.S. Pat. No. 3,336,751, Rifkin et al, Solid Propellant Composition Containing Liquid Organometallic Compound and Method of Use, the use of noncombustible particulate additives, and the addition of a material such as aluminum which produces a fine particulate oxide in the combustion chamber, thereby in some way decreasing the tendency toward combustion stability. The latter technique has been so widely used that state-of-the-art propellants now normally include aluminum as a fuel material, workers in the art sometimes forgetting that the original function of the aluminum was as a stability enhancer.
Unfortunately in many applications, the smoke produced by an aluminum containing propellant cannot be tolerated. For example, in manned spacecraft in which the viewports or cameras are in a position to be exposed to the exhaust fumes, the fogging created upon the firing of such motors can cause complete obscuration of vision. In spin stabilized rocket motors the centrifugal action of the motor causes erratic burning as a result of the centrifuging of the aluminum oxide particles to the wall of the combustion chamber. In tactical weapons systems, the smoke produced by the firing of the motor enables effective countermeasures to be taken against both the missile and the launch site. Recent developments in polymer chemistry have produced hydroxy-terminated polybutadiene (HTPB) binders with which extremely high solids loading of ammonium perchlorate (AP) can be obtained. By obtaining 88 to 90% solid loadings of AP, high specific impulses can be obtained which are very useful in those applications in which smokeless propellants are required. Unfortunately, the high solids loading of AP with HTPB binder result in a propellant which is very susceptible to combustion instability and tends to aggravate the problem already existing as a result of the deletion of the aluminum fuel material. Accordingly, combustion instability is a major problem in advanced smokeless propellants. As has been pointed out above, combustion instability can be caused to occur in the more conventional state-of-the-art propellants merely by choosing to operate them at higher chamber pressures. Thus, while this invention is particularly useful in smokeless propellants, its utility should not be construed as being limited thereto. According to this invention, an additive in relatively small amounts has been found to extend the range of stable burning of composite propellant into regions which, for a particular composition, could not heretofore be obtained.

Additive for reducing combustion instability in composite solid propellants


An optical data distribution system, for densely packed transmitter/receiver modules, of a phased-array antenna which includes an optical source and a plurality of light bars for distributing the optical energy to the photoconductor of each respective transmitter/receiver module. Each bifurcated light bar has an entrance aperture coupled to the optical source through a star coupling and branched light distributing elements branching from the entrance aperture air gap bridging optics to direct the light from each output aperture of fiber bundles to the photodetector.

1. Field of the Invention
The present invention relates to control signal distribution for T/R (transmitter/receiver) modules of a phased-array antenna, and more particularly to a control-signal distribution system for densely packaged T/R modules of a phased-array antenna.
2. Discussion of the Background
Phased-array antennas for use in smaller aircraft must of necessity be small. In order to achieve the required antenna performance with a small antenna, it is necessary to operate at a high radio frequency (e.g., X-band) and to employ a large number of radiating elements and associated T/R modules. The small antenna size and the large number of T/R modules are reflected in the packaging density. Under these conditions, it is difficult to effectively distribute control signals in such dense phased-array antennas with existing hardware. For example, hardwired signal interfaces to the modules are impractical because it is difficult to make reliable connections to a large number of T/R modules without causing excessive crosstalk between power and data conductors.
Optical data distribution technology is known to have a potential to solve these problems. For example, the optical data transmission path which carries the control-signal lends itself to being reliably connected to the input of the phased-array antennas. Although optical data distribution technology has been applied successfully to large size, low frequency, phased-array antennas (e.g., AST surveillance antennas), it has not been successfully applied to small-size, high-frequency, phased-array antennas having a large number of miniaturized T/R modules because the small-size, high-frequency antennas require high packaging density. Thus, the space available for accommodating signal distribution is extremely limited. This large number of miniaturized T/R modules typically requires closer spacing between the modules than does the large-size, low-frequency, phased-array antennas.
In dense/packed phased-array antennas, it is further required that control-signal highways which terminate within each T/R module should be efficient in terms of optical energy transfer ratio for signal delivery to the T/R module. For example, the BER (Bit Error Rate) for the control-signal at each T/R module should be better than 10.sup.-9. This in turn demands uniform optical energy distribution to each T/R module and efficient coupling of the optical energy across air gaps with low sensitivity to positional tolerances. At present, this type of optical energy distribution is not achievable in small-size, high-frequency, phased-array antennas.

Optical data distribution system for phased-array antenna


An improved hydraulic system for a twin propeller marine propulsion unit. A vertical drive shaft is operably connected to the engine of the propulsion unit and carries a pinion that drives a pair of coaxial bevel gears. An inner propeller shaft and an outer propeller shaft are mounted concentrically in the lower torpedo section of the gear case and each propeller shaft carries a propeller. To provide forward movement for the watercraft, a sliding clutch is moved in one direction to operably connect the first of the bevel gears with the inner propeller shaft to drive the rear propeller. A hydraulically operated multi-disc clutch is actuated when engine speed reaches a pre-selected elevated value to operably connect the second of the bevel gears to the outer propeller shaft, to thereby drive the second propeller in the opposite direction. The hydraulic system for actuating the multi-disc clutch includes a pump connected to the inner propeller shaft, and the pump has an inlet communicating with a fluid reservoir in the gear case and has an outlet which is connected through a hydraulic line to the multi-disc clutch. A strainer, a pressure regulator and a valve mechanism are disposed in the lower gear case and are located in series in the hydraulic line. At idle and slow operating speeds the valve is held by a solenoid in a position where the fluid is dumped to the reservoir, so that the pressure of the fluid being directed to the multi-disc clutch is insufficient to engage the clutch. At engine speeds above a preselected value, the solenoid is deenergized and the valve is then biased to a position where the fluid is delivered to the multi-disc clutch to engage the clutch and cause operation of the second propeller.

Certain marine propulsion units, such as outboard drives and inboard/outboard stern drives, utilize a forward-neutral-reverse transmission along with twin propellers. The typical twin propeller system includes a vertical drive shaft which is operably connected to the engine and is journaled for rotation in the lower gearcase. The lower end of the drive shaft carries a pinion which drives a pair of coaxial bevel gears that are located in the lower torpedo-shaped section of the gearcase. Inner and outer propeller shafts are mounted concentrically in the lower section and each propeller shaft carries a propeller, with the propeller of the outer shaft being located forwardly of the propeller of the inner shaft.
U.S. Pat. No. 4,793,773 is directed to a twin propeller propulsion system in which both propellers are rotated at the same speed, but in opposite directions, during forward movement of the watercraft. With this system, a mechanism is provided to disconnect the outer propeller shaft when the watercraft is moved in the reverse direction. Thus, with the system shown in the aforementioned patent, both propellers are operated during forward movement of the watercraft, but only the inner propeller shaft and the rear propeller are operated during reverse movement.
Co-pending U.S. Pat. application Ser. No. 08/719,633, filed Sep. 25, 1996, now U.S. Pat. No. 5,766,047 is directed to a twin propeller marine propulsion system in which, during forward movement of the watercraft, only one of the propellers is driven at low engine speed and the second propeller is driven when the engine speed reaches a pre-selected elevated value.
In accordance with the construction of the aforementioned patent application, a sliding clutch mechanism having forward neutral and reverse positions is employed to selectively engage the inner propeller shaft with the bevel gears to thereby rotate the inner propeller shaft and the rear propeller in both the forward and reverse directions. In addition, a hydraulically operated multiple disc clutch located in the lower torpedo section is employed to selectively cause engagement of one of the bevel gears with the outer propeller shaft when the engine speed reaches a pre-selected elevated value, normally in the range of 3,500 rpm to 7,000 rpm, to thereby cause the second or forward propeller to rotate in the opposite direction from the rear propeller. With this construction, only the rear propeller is driven at low forward speeds, while at high forward speeds both propellers are driven.
As described in the aforementioned patent application, the multiple disc clutch is moved to the engaged position at the pre-selected elevated engine speed by supplying pressurized fluid to a piston which engages the multiple clutch discs and moves the discs to a contacting or driving position. With this construction, only a single propeller is operable at low speeds, and once the pre-selected elevated engine speed has been achieved, the second propeller is then driven, resulting in a significant improvement in acceleration of the watercraft when getting on plane.

Marine propulsion unit with hydraulic pump


A high-performance superconducting digital-to-analog (D/A) converter providing asynchronous high-speed, low-power D/A conversion. The high-performance superconducting D/A converter includes a double-junction superconducting quantum interference device (SQUID) voltage divider circuit, which generates a series of discrete binary voltages, and a double-junction SQUID voltage selector circuit, which selects the binary voltages in accordance with a digital input signal. The currents generated by the selected binary voltages are added together to produce an analog output current that represents the digital input.

This invention relates generally to digital-to-analog converters and, more particularly, to high-performance superconducting digital-to-analog converters.
High-performance superconducting digital-to-analog (D/A) converters are required in a variety of applications for high-speed, low-power D/A conversion. One such application is digital superconducting flux-locked magnetometers, which provide highly sensitive detection of very small magnetic fields. Digital superconducting magnetometers have been proposed for use in such diverse areas as oil and mineral exploration, submarine and mine detection, and noninvasive medical diagnostic procedures.
A superconducting magnetometer typically employs one or more superconducting quantum interference devices (SQUID's) for measuring the strength of a magnetic field. A SQUID is a superconducting loop having a Josephson tunnel junction as a weak link in the loop. The weak link functions as a flux gate to allow the amount of magnetic flux in the loop to change. The amount of magnetic flux in the superconducting loop is quantized, which means that the loop supports only integer multiples of a flux quantum. When a SQUID is placed in a magnetic field, a superconducting current flows around the loop to oppose any change in the magnetic flux. However, when the opposing current exceeds the critical current of the superconducting loop, the Josephson junction opens the loop and allows one or more flux quantum to enter.
A superconducting magnetometer is constructed by adding a feedback path to a SQUID, thus allowing a current to be applied to the superconducting loop that cancels the current induced by the magnetic field. This maintains the magnetic flux in the loop constant, while the amount of current applied to the loop to balance out the induced current is a measure of the magnetic field. In a digital superconducting magnetometer, a superconducting D/A converter is required in the feedback path to convert the digital feedback signal to an analog current.
Conventional superconducting D/A converters typically employ a binary network of latching Josephson junctions and resistors which generates a set of reference voltages based on the current-voltage characteristics of the junctions. The voltage of a Josephson junction is zero in the superconducting or zero voltage state and equal to the energy gap voltage of the superconducting material in the nonsuperconducting or voltage state. However, using the energy gap voltage as the reference voltage requires uniform Josephson junctions having steep conductances at the gap voltage. The uniformity in the energy gap voltage must be 1/2 bit greater than 2.sup.N, which for 10 bits of resolution (N), requires less than a 5.times.10.sup.-4 variation in the gap voltages of the Josephson junctions, or about one microvolt. The latching nature of conventional superconducting D/A converters also requires synchronous clocking to reset the junctions during each clock cycle, resulting in high power dissipation. Accordingly, there has been a need for a superconducting D/A converter that does not have these drawbacks. The present invention clearly fulfills this need.

High-performance superconducting digital-to-analog converter employing double-junction squid flip-flops


A purge system includes an airflow source to provide an airflow, and a fuel tank, including: a tank volume including a tank ullage, at least one inlet, wherein the at least one inlet is in fluid communication with the tank ullage and the airflow source to provide the airflow as an inbound airflow to the tank ullage, and at least one outlet, wherein the at least one outlet is in fluid communication with the tank ullage and an overboard location outside the aircraft to direct the inbound airflow as an outbound airflow from the tank ullage to the overboard location.

The subject matter disclosed herein relates to passivation systems, and more particularly, to passivation systems for use with aircraft fuel systems.
Fuel systems utilized within an aircraft may employ inerting systems to reduce the flammability of fuel vapors within the tank ullage of the fuel tank. Inerting systems within fuel systems may be utilized to provide a nitrogen-enriched environment, an oxygen-depleted environment, etc., to prevent ignition of fuel vapors. Inerting systems add additional weight, complexity, and expense.


A method for assisting the laser drilling of a hole in a part comprises the steps of providing a camera mounted to the laser, providing a target hole at a first position, capturing a first image of the target hole at the first position with the camera, moving the target hole to a second position and capturing a second image of the target hole, and computing a drilling location of the target hole from the first image and the second image, said computed drilling location used to laser drill the target hole.

(1) Field of the Invention
The present invention relates to an apparatus, and method for so using, for locating and finish drilling cooling holes using a stereovision guided laser drilling process.
(2) Description of the Related Art
In the turbine blades/vanes manufacturing process, the parts are first precision-cast and then the cooling holes are installed either by laser drilling or by electrical discharge machining (EDM). A method that casts the cooling holes at the time of casting the part, offers the advantage of process simplification with enhanced quality and precision. In addition, complex cooling hole schemes, such as shaped non-cylindrical holes with complex diffuser and metering section geometries, can be cast in by this process that are difficult to directly laser drill or EDM. However, even a high-precision casting process cannot fully cast the complete hole geometry due to the limitations of the casting process (cold shut, core mismatch, slag formation, etc.). These limitations result in partially cast holes—with most of the top portion of the hole geometry completely cast and the bottom portion of the hole geometry shut or plugged by debris or slag.
A CATSCAN system using Computer-aided Tomography, can give scanned slices of the part and by taking the scans very closely one can build up the inside and outside profiles of a part but this takes an inordinately long time to scan at the precision needed and also requires a separate radiation chamber. The evolving QMP (Quartz Micro Probing) system can locate the holes precisely but the rough locations must be known before hand. Also QMP takes a long time and cannot be mounted on the laser machine bed. 3D machine vision alternatives including structured light techniques, have proven difficult due to the depth or shallow angle of the cooling holes. What is therefore needed is an apparatus, and method for using the apparatus, which overcomes the shortcomings of the related art—capable of being mounted on the laser machine alongside the laser drill and with the necessary precision needed.

Stereovision guided laser drilling system


A valve device (D) of the type used for a breathing apparatus (A) includes a mask section (10) that is adapted for mating with a desired subject (U), such as about a mouth and nose. An inlet tube (12) communicates a desired fluid, such as oxygen, into an interior chamber (16) of the mask (10). At least one plate assembly (18) has a thin, pliable outer section (20) to act as a flapper. A plate mount (22) retains the plate assembly (18), and has at least one pair of passages (24a and 24b) formed therethrough for communicating the fluid (14) out of the interior chamber (16) and an external fluid into the interior chamber (16) of the mask (10). Compatible portions (26a and 26b) of the pliable outer section (20) movably cover the passages (24a and 24b) in the plate mount (22) forming at least one inlet valve (28) that permits the flow of the external fluid into the interior chamber (16) and a second outlet valve (30) that permits the exhaust of combined fluid out of the interior chamber (16).

1. Technical Field
The invention relates to the field of valved devises and, more particularly, to a valved structure adapted for use as a breathing apparatus.
2. Background Art
Air masks used in conjunction with a breathing apparatus are well known in the art. Exemplary of such types of breathing apparatus include oxygen masks used for high altitude flying, emergency oxygen masks used for loss of pressure in aircraft, and medical oxygen therapy treatment units, both emergency and for hospital usage.
Oxygen masks are used with the breathing apparatus as an interface between the user and the source of gas or other desired fluid. The mask is fitted to the general contour of one's face about their mouth and nose, typically; Characteristic examples of such known oxygen masks used in oxygen therapy uses are those manufactured or sold by Hudson Oxygen-Therapy Sales Co. of Temecula, Calif., Life Support, Inc. of Melbourne, Fla., and Baxter Healthcare Corporation of Valencia, Calif.
As is generally the case with the above cited medical oxygen masks, such masks either do not include a valve regulating or controlling the passage of the gas or include a single valve that permits fluid flow in a single direction.
In U.S. Pat. No. 2,936,779 (Kindred) a mask having a flapper valve is disclosed. The flapper valve as taunt in Kindred permits the flow of the gas or other desired fluid in a single direction and forms a seal against the flow of the fluid in a reverse direction or when the flow ceases.
While the above cited references introduce and disclose a number of noteworthy advances and technological improvements within the art, none completely fulfills the specific objectives achieved by this invention.


Squarylium compounds of the formula: ##STR1## in which: Q.sup.1 and Q.sup.2 are each a Chromophoric group having an unsaturated system conjugated with the squarylium ring and such that in the compounds of formulae Q.sup.1 CH.sub.2 R.sup.1 and Q.sup.2 CH.sub.2 R.sup.2 the methylene hydrogens are active hydrogens;. R.sup.1 and R.sup.2 are each independently a hydrogen atom or an aliphatic or cycloaliphatic group; and PA0 R.sup.3, R.sup.4 and R.sup.5 are each independently a hydrogen atom, or an aliphatic, cycloaliphatic, aromatic or heterocyclic group, or an electron-withdrawing group able to lower the electron density at the carbon atom to which it is attached, subject to the provisoes that:. two of R.sup.3, R.sup.4 and R.sup.5 may form a divalent group of which a single atom is double bonded to the carbon atom to which the two groups are attached, or all three of R.sup.3, R.sup.4 and R.sup.5 may form a trivalent group of which a single atom is triple bonded to the carbon atom to which the three groups are attached, or PA1 two of R.sup.3, R.sup.4 and R.sup.5 may, together with the carbon atom to which they are attached, form a ring, or all three of R.sup.3, R.sup.4 and R.sup.5 may, together with the carbon atom to which they are attached, form an unsaturated ring,. are useful as near infra-red absorbers. The presence of the --CR.sup.3 R.sup.4 R.sup.5 group on the squarylium ring enables changes in absorption wavelength to be achieved by modifications of this group, and also allows functional groups to be incorporated into the dye without changing the chromophoric groups.

1. Field of the Invention
This invention relates to squarylium dyes, and processes and intermediates for the preparation thereof. More specifically, it relates to such dyes and intermediates in which two chromophoric groups occupy the 1- and 3-positions of the squarylium ring, while the 2-position bears a substituent in which a carbon atom is bonded directly to the squarylium ring.
2. References to Related Applications
Copending patent application U.S. Ser. No. 07/616,639, filed Nov. 21, 1990, and its continuation in part, application U.S. Ser. No. 07/795,038, of even date herewith, both assigned to the same assignee as the present application describe dyes comprising an inner salt of a compound of the formula: EQU Q.sup.1 .dbd.Z--Q.sup.2
wherein:
Q.sup.1 is a 4-(benz[b]-4H-pyrylium)methylidene, 4-(benz[b]-4H-thiopyrylium)methylidene or 4-(benz[b]-4H-selenopyrylium)methylidene grouping;
Z is a 1,3-(2-hydroxy-4-oxo-2-cyclobutylidene) or 1,3-(2-hydroxy-4,5-dioxo-2-cyclopentylidene) ring; and
Q.sup.2 is a 4-(benz[b]-4H-pyran-4-ylidene)methyl, 4-(benz[b]-4H-thiopyran-4-ylidene)methyl or 4-(benz[b]-4H-selenopyran-4-ylidene)methyl grouping;
wherein at least one of the groupings Q.sup.1 and Q.sup.2 carries at its 2-position a substituent in which a non-aromatic carbon atom is bonded directly to the benzpyrylium, benzthiopyrylium or benzselenopyrylium nucleus, subject to the proviso that if this 2-substituent contains an aromatic nucleus, this aromatic nucleus is not conjugated with the benzpyrylium, benzthiopyrylium or benzselenopyrylium nucleus to which it is attached. These dyes have high absorptions in the near infra-red, and improved solubility in semi-polar solvents and plastics. The dyes disclosed in these applications include certain infra-red dyes used in the thermal imaging medium described below with reference to FIG. 4.
Copending application U.S. Ser. No. 07/696,222, filed May 6, 1991 and assigned to the same assignee as the present application, describes and claims the squarylium compounds of formulae D, E, J and K described below with reference to FIG. 1, together with similar compounds containing different heterocyclic nuclei, and squarylium compounds of the formula: ##STR2## wherein Q.sup.1 and Q.sup.2 are each independently a heterocyclic nucleus such that in the compounds of formulae Q.sup.1 CH.sub.2 R.sup.1 and Q.sup.2 CH.sub.2 R.sup.2 the methylene hydrogens are active hydrogens, the atoms of Q.sup.1 and Q.sup.2 which are bonded directly to the CR.sup.1 and CR.sup.2 groupings respectively each being part of an aromatic ring, and Q.sup.1 and Q.sup.2 are different, and R.sup.1 and R.sup.2 are each independently a hydrogen atom or an aliphatic or cycloaliphatic group. The disclosure of this copending application is discussed below in more detail with reference to FIG. 1.
Copending applications U.S. Ser. Nos. 07/695,641; 07/696,196 and 07/695,932, all filed May 6, 1991 and all assigned to the same assignee as the present application, describe and claim imaging media comprising a color-forming layer comprising a thermal color-forming composition adapted to undergo a change of color upon increase in the temperature of the color-forming layer above a color-forming temperature for a color-forming time. Preferred imaging media described in these three applications comprise three separate color-forming layers containing yellow, cyan and magenta thermal color-forming compositions; each of these color-forming compositions comprises a color-forming compound which undergoes a change of color upon heating above the color-forming temperature for the color-forming time, and an infra-red absorber (which may be referred to hereinafter as an infra-red dye) capable of absorbing infra-red radiation and thereby generating heat in the color-forming layer. The three color-forming layers use infra-red absorbers absorbing at differing wavelengths so that each color-forming layer can be imaged independently; for example, specific imaging media disclosed in these three applications use infra-red absorbers having peak absorptions at approximately 792, 822 and 869 nm.
Copending application U.S. Ser. No. 07/795,034, of even date herewith and assigned to the same assignee as the present application, describes infra-red dyes generally similar to those of the present invention, but in which the 2-substituent on the squarylium ring is an amino or substituted amino group. The dyes described in this Application include the 2-aminosquarylium dye used in the thermal imaging medium described below with reference to FIG. 4.
Copending application U.S. Ser. No. 07/795,101, of even date herewith, by Rita S. Shon Baker et al. and assigned to the same assignee as the present application, describes and claims thermal imaging media generally similar to those described in the aforementioned applications U.S. Ser. Nos. 07/695,641; 07/696,196 and 07/695,932 but in which at least one imaging layer contains a metal cation. Preferred imaging media described in this application have imaging layers containing zinc acetate, as described below with reference to FIG. 4.
The disclosures of all the aforementioned copending applications are herein incorporated by reference.

Substituted squarylium dyes, and processes and intermediates for the preparation thereof


A method of packaging a semiconductor die includes the use of an embedded ground plane or drop-in embedded unit. The embedded unit is a single, stand-alone unit with at least one cavity. The embedded unit is placed on and within an encapsulation area of a process mounting surface. The embedded unit may have different sizes and shapes and a number of different cavities that can be placed in a predetermined position on a substrate, panel or tape during processing of semiconductor dies that are embedded into redistributed chip package (RCP) or wafer level package (WFL) panels. The embedded unit provides the functionality and design flexibility to run a number of embedded units and semiconductor dies or components having different sizes and dimensions in a single processing panel or batch and reduces die drift, movement or skew during encapsulation and post-encapsulation cure.

The present invention relates to packaging of integrated circuits and, more particularly, to encapsulating semiconductor dies with an encapsulation material.
Semiconductor packages are containers for integrated circuits formed on a semiconductor die. Typically, the die is encapsulated with an encapsulant material such as a plastic resin that forms a protective exterior surface of the semiconductor package. The package has electrical interconnects between contact pads of the integrated circuit on the die and exposed input/output (I/O) pins for interconnecting the integrated circuit with external circuitry.
In the process of encapsulating the die, during curing of the encapsulant, the properties of the encapsulant material can cause the die to drift and move position. This post-encapsulation cure, die drift, or skew results in the die having a different actual post-encapsulation position than when it was initially placed on a panel before the encapsulation process. Die drift complicates later high precision processing steps, such as interconnecting die bonding pads or connection points of the die with interconnects, feature and trace positioning on photo masks, and aperture positioning on printing or ball drop screens for connection between die bonding pads to metal layers and bumps or balls. Any misalignment or miscoupling between the interconnects and the die pads may result in device and package failure, lowering manufacturing yield.
In an attempt to compensate for die drift, a pick and place position of the die on the surface support panel or frame is determined before encapsulation using empirical data. However, relying on die pitch compensation still results in misalignments between connection points and interconnects. In particular, the error associated with die pitch compensation has been increasing due to the industry trend for a smaller chip footprint yet with an increased density of connection points and interconnects.
In an attempt to overcome the limitations of die pitch compensation, a sheet of perforated single plane metal known as an embedded ground plane plate or frame has been implemented in the die encapsulation process. The embedded ground plane plate is positioned on top of and extends across the entire area or breadth of the mold or encapsulating area of the panel or substrate surface. A die is placed on the substrate surface in each perforated area of the embedded ground plane plate. Although in the advent of embedded ground plane plates some improvements have been achieved in reducing die drift or skew, there are limitations with the use of conventional embedded ground planes. During assembly, a single embedded ground plane plate or sheet is used. Often, however, it is desirable to have different thicknesses and materials of the embedded ground plane plate around different sized semiconductor dies with different sizes and dimensions and electrical, thermal and mechanical requirements in a single batch.
Another limitation with conventional embedded ground plane plates is panel warpage caused by an imbalance of panel expansion after encapsulation cure between the embedded components of the panel in the encapsulant. As the embedded ground plane plate extends across the entire area of the surface of the panel, when the panel warps, the panel is not able to be adequately held to a wafer chuck table by a vacuum without additional assistance such as a mechanical stiffener. However, mounting a mechanical stiffener to the panel introduces additional cost and processing time.
Additionally, with traditional embedded ground plane plates there can be package reliability failure due to delamination propagation that arises at the embedded ground plane plate to the encapsulant interface and embedded ground plane plate to dielectric interface during package sawing at singulation, which contributes to lower processing yield. Accordingly, there is a need for addressing or at least alleviating the above limitations and problems.