Processes are provided for preparing compounds with a fused ring structure of formula (XIV). Such products include ecteinascidins and have a spiroamine-1,4-bridge. The process involving forming a 1,4 bridge using a 1-labile, 10-hydroxy, 18-protected hydroxyl, di-6,8-en-5-one fused ring compound. After formation of the 1,4 brige, C-18 protection is removed before spiroamine introduction.

European Patent 309,477 relates to ecteinascidins 729, 743, 745, 759A, 759B and 770. The ecteinascidin compounds are disclosed to have antibacterial and other useful properties. Ecteinascidin 743 is now undergoing clinical trials as an antitumour agent.
Ecteinascidin 743 has a complex tris(tetrahydroisoquinolinephenol) structure of the following formula (I):

It is currently prepared by isolation from extracts of the marine tunicate Ecteinascidin turbinata. The yield is low, and alternative preparative processes have been sought.
A synthetic process for producing ecteinascidin compounds is described in U.S. Pat. No. 5,721,362, see also WO 9812198 which is incorporated herein by reference in full. The claimed method is long and complicated, there being 38 Examples each describing one or more steps in the synthetic sequence to arrive at ecteinascidin 743.
In the known synthetic process, a 1,4 bridge is formed using a 1-labile, 10-hydroxy, 18-protected hydroxy, di-6,8-en-5-one fused ring compound. As shown in Example 33, a compound (13) is converted to compound (14):

According to the known synthetic process, a spiroquinoline is then formed in the 1,4 bridge by the steps of Examples 34 to 36, and the 18-MOM protecting group is removed to give ecteinascidin 770 which can then be converted to ecteinascidin 743.
Claim 25 of U.S. Pat. No. 5,721,362 is directed at an intermediate phenol compound of a given formula (11), which we refer to also as Intermediate 11 or Int-11. It has the following bis(tetrahydroisoquinolinephenol) structure (II):
where MOM is a methoxymethyl substituent and TBDPS is a tert-butyldiphenylsilyl substituent.
From Intermediate 11 it is possible to synthesise another interesting antitumour agent, phthalascidin, see Proc. Natl. Acad. Sci. USA, 96, 3496-3501, 1999. Phthalascidin is a bis(tetrahydroisoquinolinephenol) derivative of formula (III):

In ecteinascidins 743 and 770, the 1,4 bridge has the structure of formula (IV):

Other known ecteinascidins include compounds with a different bridged cyclic ring system, such as occurs in ecteinascidin 722 and 736, where the bridge has the structure of formula (V):
ecteinascidins 583 and 597, where the bridge has the structure of formula (VI):
and ecteinascidin 594 and 596, where the bridge has the structure of formula (VII):

The complete structure for these and related compounds is given in J. Am. Chem. Soc. (1996) 118, 9017-9023. This article is incorporated by reference.
Other literature on the ecteinasdin compounds includes: Corey, E. J., J. Am. Chem. Soc., 1996, 118 pp. 9202-9203; Rinehart, et al., Journal of Natural Products, 1990, "Bioactive Compounds from Aquatic and Terrestrial Sources", vol. 53, pp. 771-792; Rinehart et al., Pure and Appl. Chem., 1990, "Biologically active natural products", vol 62, pp. 1277-1280; Rinehart, et al., J. Org. Chem., 1990, "Ecteinascidins 729, 743, 745, 759A, 759B, and 770: potent Antitumour Agents from the Caribbean Tunicate Ecteinascidia turninata", vol. 55, pp. 4512-4515; Wright et al., J. Org. Chem., 1990, "Antitumour Tetrahydroisoquinoline Alkaloids from the Colonial ascidian Ecteinascidia turbinata", vol. 55, pp. 4508-4512; Sakai et al., Proc. Natl. Acad. Sci. USA 1992, "Additional anitumor ecteinascidins from a Caribbean tunicate: Crystal structures and activities in vivo", vol. 89, 11456-11460; Science 1994, "Chemical Prospectors Scour the Seas for Promising Drugs", vol. 266, pp. 1324; Koenig, K. E., "Asymmetric Synthesis", ed. Morrison, Academic Press, Inc., Orlando, Fla., vol. 5, 1985, p. 71; Barton, et al., J. Chem Soc. Perkin Trans., 1, 1982, "Synthesis and Properties of a Series of Sterically Hindered Guanidine bases", pp. 2085; Fukuyama et al., J. Am. Chem. Soc., 1982, "Stereocontrolled Total Synthesis of (+)-Saframycin B", vol. 104, pp. 4957; Fukuyama et al., J. Am. Chem. Soc., 1990, "Total Synthesis of (+)-Saframycin A", vol. 112, p. 3712; Saito, et al., J. Org. Chem., 1989, "Synthesis of Saframycins. Preparation of a Key tricyclic Lactam Intermediate to Saframycin A", vol. 54, 5391; Still, et al., J. Org. Chem., 1978, "Rapid Chromatographic Technique for Preparative Separations with Moderate Resolution", vol. 43, p. 2923; Kofron, W. G.; Baclawski, L. M., J. Org. Chem., 1976, vol. 41, 1879; Guan et al., J. Biomolec. Struc. & Dynam., vol. 10, pp. 793-817 (1993); Shamma et al., "Carbon-13 NMR Shift Assignments of Amines and Alkaloids", p. 206 (1979); Lown et al., Biochemistry, 21, 419-428 (1982); Zmijewski et al., Chem. Biol. Interactions, 52, 361-375 (1985); Ito, CRC Crit. Rev. Anal. Chem., 17, 65-143 (1986); Rinehart et al., "Topics in Pharmaceutical Sciences 1989", pp. 613-626, D. D. Breimer, D. J. A. Cromwelin, K. K. Midha, Eds., Amsterdam Medical Press B. V., Noordwijk, The Netherlands (1989); Rinehart et al., "Biological Mass Spectrometry", 233-258 eds. Burlingame et al., Elsevier Amsterdam (1990); Guan et al., Jour. Biomolec. Struct. & Dynam., vol. 10 pp. 793-817 (1993); Nakagawa et al., J. Am. Chem. Soc, 111: 2721-2722 (1989); Lichter et al., "Food and Drugs from the Sea Proceedings" (1972), Marine Technology Society, Washington, D.C. 1973, 117-127; Sakai et al., J. Am. Chem. Soc., 1996, 118, 9017; Garcia-Rocha et al., Brit. J. Cancer, 1996, 73: 875-883; and Pommier et al., Biochemistry, 1996, 35: 13303-13309.
Further compounds are known which lack a bridged cyclic ring system. They include the bis(tetrahydroisoquinolinequinone) antitumor-antimicrobial antibiotics safracins and saframycins, and the marine natural products renieramicins and xestomycin isolated from cultured microbes or sponges. They all have a common dimeric tetrahydroisoquinoline carbon framework. These compounds can be classified into four types, types I to IV, with respect to the oxidation pattern of the aromatic rings.
Type I, dimeric isoquinolinequinones, is a system of formula (VIII) most commonly occurring in this class of compounds, see the following table I.
TABLE IStructure of Type I Saframycin Antibiotics. SubstituentsCompoundR14aR14bR21R25aR25bR25csaframycin AHHCNOOCH3saframycin BHHHOOCH3saframycin CHOCH3HOOCH3saframycin GHOHCNOOCH3saframycin HHHCNOHCH2COCH3CH3saframycin SHHOHOOCH3saframycin Y3HHCNNH2HCH3saframycin Yd1HHCNNH2HC2H5saframycin Ad1HHCNOOC2H5saframycin Yd2HHCNNH2HHsaframycin Y2bHQbCNNH2HCH3saframycin Y2b-dHQbCNNH2HC2H5saframycin AH2HHCNHaOHaCH3saframycin AH2AcHHCNHOAcCH3saframycin AH1HHCNOHaHaCH3saframycin AH1AcHHCNOAcHCH3saframycin AR3HHHHOHCH3aassignments are interchangeable.bwhere the group Q is of formula (IX):
Type I aromatic rings are seen in saframycins A, B and C; G and H; and S isolated from Streptomyces lavendulae as minor components. A cyano derivative of saframycin A, called cyanoquinonamine, is known from Japanese Kokai JP-A2 59/225189 and 60/084,288. Saframycins Y3, Yd1, Ad1, and Yd2 were produced by S. lavendulae by directed biosynthesis, with appropriate supplementation of the culture medium. Saframycins Y2b and Y2b-d dimers formed by linking the nitrogen on the C-25 of one unit to the C-14 of the other, have also been produced in supplemented culture media of S. lavendulae. Saframycins AR1 (=AH2,), a microbial reduction product of saframycin A at C-25 produced by Rhodococcus amidophilus, is also prepared by nonstereoselective chemical reduction of saframycin A by sodium borohydride as a 1:1 mixture of epimers followed by chromatographic separation [the other isomer AH1 is less polar]. The further reduction product saframycin AR3, 21-decyano-25-dihydro-saframycin A, (=25-dihydrosaframycin B) was produced by the same microbial conversion. Another type of microbial conversion of saframycin A using a Nocardia species produced saframycin B and further reduction by a Mycobacterium species produced saframycin AH1Ac. The 25-O-acetates of saframycin AH2 and AH1 have also been prepared chemically for biological studies.
Type I compounds of formula (X) have also been isolated from marines sponges, see Table II.
TABLE IIStructures of Type I Compounds from Marine Sponges. SubstituentsR14aR14bR21Rrenieramycin AOHHH—C(CH3)═CH—CH3renieramycin BOC2H5HH—C(CH3)═CH—CH3renieramycin COHOO—C(CH3)═CH—CH3renieramycin DOC2H5OO—C(CH3)═CH—CH3renieramycin EHHOH—C(CH3)═CH—CH3renieramycin FOCH3HOH—C(CH3)═CH—CH3xestomycinOCH3HH—CH3
Renieramycins A-D were isolated from the antimicrobial extract of a sponge, a Reniera species collected in Mexico, along with the biogenetically related monomeric isoquinolines renierone and related compounds. The structure of renieramycin A was initially assigned with inverted stereochemistry at C-3, C-11, and C-13. However, careful examination of the 1H NMR data for new, related compounds renieramycins E and F, isolated from the same sponge collected in Palau, revealed that the ring junction of renieramycins was identical to that of saframycins. This result led to the conclusion that the formerly assigned stereochemistry of renieramycins A to D must be the same as that of saframycins.
Xestomycin was found in a sponge, a Xestospongia species collected from Sri Lancan waters.
Type II compounds of formula (XI) with a reduced hydroquinone ring include saframycins D and F, isolated from S. lavendulae, and saframycins Mx-1 and Mx-2, isolated from Myxococcus xanthus. See table III.
TABLE IIIType II Compounds SubstituentsCompoundR14aR14bR21R25aR25bR25csaframycin DOOHOOCH3saframycin FOOCNOOCH3saframycin Mx-1HOCH3OHHCH3NH2saframycin Mx-2HOCH3HHCH3NH2
The type III skeleton is found in the antibiotics safracins A and B, isolated from cultured Pseudomonas fluorescens. These antibiotics of formula (XII) consist of a tetrahydroisoquinoline-quinone subunit and a tetrahydroisoquninolinephenol subunit.
where R21 is —H in safracin A and is —OH in safracin B.
Saframycin R, the only compound classified as the Type IV skeleton, was also isolated from S. lavendulae. This compound of formula (XIII), consisting of a hydroquinone ring with a glycolic ester sidechain on one of the phenolic oxygens, is conceivably a pro-drug of saframycin A because of its moderate toxicity.

All these known compounds have a fused system of five rings (A) to (E) as shown in the following structure of formula (XIV):

The rings A and E are phenolic in the ecteinascidins and some other compounds, while in other compounds, notably the saframycins, the rings A and E are quinolic. In the known compounds, the rings B and D are tetrahydro, while ring C is perhydro.

Synthetic process for the manufacture of an ecteinaschidin compound


Radon is removed from a gas in an apparatus comprising: (a) a liquid-contacting apparatus having a shielded reservoir containing a fresh working liquid in which radon is soluble; and (b) a means for causing a stream of gas containing radon to pass through the liquid-contacting apparatus. When the radon level in the working liquid reaches a certain level, the working liquid is either taken out of service and stored until the radon level is reduced or the working liquid is diluted with additional working liquid having no radon.

Radon is a gaseous element having the atomic number 86, i.e., an atom of radon has 86 protons in its nucleus and 86 electrons. Radon is a member of a group of elements known as the noble gases because they are relatively unreactive. Radon exists in the form of eighteen different isotopes. Isotopes are atoms of an element that contain different numbers of neutrons in their nuclei. Particular isotopes are commonly identified by their total number of protons and neutrons. For example, radon-222 is an isotope containing 86 protons and 136 neutrons.
All isotopes of radon are radioactive. Radioactivity is a process in which atoms undergo spontaneous nuclear transformations or decay by emitting atomic particles and/or electromagnetic energy. The most common types of radioactive decay are alpha decay (which produces an alpha particle consisting of two protons and two neutrons) and beta decay (which produces an electron). Electromagnetic radiation in the form of a gamma ray is also emitted as part of each alpha and beta decay. Each gamma ray is emitted in a random direction and travels in a straight line until absorbed.
The rate of radioactivity is measured by its half-life. A half-life is the time for one-half of the atoms to undergo radioactive transformation. Seventeen of the eighteen radon isotopes have half-lives of a minute or less. Radon-222 is the most stable of the radon isotopes and has a half-life of 3.8 days. Radon-222 decays through several intermediates (also known as decay progeny) into lead-210, an isotope of lead (atomic number 82) having a half life of 22 years. Lead-210 decays through intermediates into the stable, nonradioactive lead-206.
Radon is constantly being formed by the radioactive decay of subterranean uranium (atomic number 92). Uranium is present primarily in the form of the uranium-238 isotope. Uranium-238 is radioactive with a half life of 4.5 billion years. Uranium-238 decays through several intermediates into radon-222. The slow decay of uranium-238 has been occurring since the earth was formed. The decay chain from uranium-238 via radon-222 to lead-206 produces multiple alpha, beta, and gamma emissions. The highest energy gamma ray emission in this decay chain is about 7.7 MeV (mega electron volts).
Radon is also being formed by the radioactive decay of subterranean thorium (atomic number 90). Thorium is present primarily in the form of the thorium-232 isotope. Thorium-232 is radioactive with a half life of 14 billion years. Thorium-232 decays through several intermediates into radon-220. Radon-220 has a half-life of about one minute. Radon-220 decays through several intermediates into stable, nonradioactive lead-208. The decay chain from thorium-232 via radon-220 to lead-208 also produces multiple alpha, beta, and gamma emissions. For brevity, the term "radon" is used hereinafter to refer to all the isotopes of radon.
As a result of the ongoing formation of radon from radioactive decay, radon gas is constantly seeping upward through rock and soil toward the surface of the earth. The radon poses no risk if it decays before reaching the surface because its decay progeny are solids that remain wherever formed. Similarly, the radon poses no risk if it reaches the atmosphere because its concentration is so small. However, radon can enter buildings and concentrate to dangerous levels in the air, particularly in basements and first floors of buildings without basements. Radon levels vary considerably at different sites, and over time at any given site. Many factors cause these variations. For example, low pressure atmospheric conditions which often occur during storms are believed to draw higher levels of radon from the ground.
Radon is the leading environmental cause of cancer in the United States and the second-leading cause of lung cancer. The harmful effects are due primarily to alpha, beta, and gamma ray emissions inside the body resulting from radon breathed into the lungs. The health risks posed by radon have become more widely recognized in the past decade. The United States Environmental Protection Agency has recommended that homeowners take corrective action if the level of radon in their homes exceeds 4 picocuries per liter (about 0.04 decays per second per liter of air). There are two basic ways to lower radon levels in a building. The first is to suppress the flow of radon into a the building. The second is to remove the radon that is already there.
One common technique for suppressing the flow of radon into a building is to seal cracks and other openings in the building foundation, often in conjunction with sub-slab decompression. However, it is difficult to identify and permanently seal every opening. Furthermore, normal settling of buildings creates new openings and reopens old ones. The flow of radon into buildings is also suppressed by placing a barrier film on or under the lowest floor. An example of such a method is disclosed in Shahar, U.S. Pat. No. 6,676,780, Jan. 13, 2004.
The most common technique for removing existing radon from the air in a building is to increase ventilation. Simply opening doors and windows can lower radon levels. However, ventilation is difficult in basements with few, if any, windows or doors. Ventilation also results in the loss of conditioned air, discomfort, security problems, and increased costs of conditioning outside air.
Another technique for removing existing radon from the air in a building is to operate a liquid-gas contacting apparatus, commonly known as a wet scrubber. A wet scrubber is an apparatus in a which a gas stream is brought into contact with a working (scrubbing) liquid by forcing the gas through the liquid, by spraying the gas with the liquid, or by some other contact method. As the gas and liquid make contact, one or more components of the gas are absorbed, captured by the clathrate mechanism, or otherwise transferred from the gas to the liquid. The terms "absorb" and "dissolve" are used herein to refer to any mechanism by which a component of a gas becomes a component of a liquid. The removal of radon from air with a wet scrubber having an oil as the working liquid is disclosed in Gross et al., U.S. Pat. No. 5,743,944, Apr. 28, 1998. Gross et al. disclose that suitable oils include vegetable oils, animal oils, and petroleum oils.
While a wet scrubber removes radon from the air, the radon absorbed into the liquid remains a health risk. If the level of radon or its decay progeny reach a level to generate 2000 picocuries per gram (pCi/g), the liquid becomes a "low-level radioactive waste" as defined by the U.S. Environmental Protection Agency and requires special handling. Gross et al. address this problem by removing the working liquid from the wet scrubber, agitating and heating the liquid to release the radon from the liquid, and then venting the released radon to the atmosphere. The immediate removal of radon from the working liquid is an expensive step that adds greatly to the complexity and cost of the wet scrubber system.
Accordingly, a demand exists for an improved wet scrubber apparatus and method for removing radon from a gas, such as the air in the interior of a building, that does not require the immediate removal of radon from the working fluid.


Polarized sunglasses and lenses, and methods related thereto, are provided that include multifocal segments and which have a total thickness of less than about 5 millimeters.

A wide range of sunglasses are available, including prescription sunglasses, polarized sunglasses, and multifocal sunglasses (such as those with bifocal segments).
Prescription lenses are generally made by grinding relatively thick lens blanks down to the shape needed for the prescriptions. Such lens blanks are often about 9 millimeters thick before grinding. Of course, because of this thickness, the lens cost is higher than that for thinner lens blanks.
Besides prescription uses, thick lens blanks have been used with polarizing films to create polarized lenses, they have been tinted for filtering, they have been made with bifocal segments for multifocal applications, and they have been used in applications that combine each of these. In each of these applications, significant costs and processing time are involved in grinding the lens blanks so that their thickness is suitable for wearing.
Thinner lens blanks, often referred to as "plano" lenses, are less expensive, and have a thickness of about less than 5 millimeters. Such plano lenses have been used with polarizing films to create polarized lenses, they have been tinted for filtering, and they have been made with bifocal segments for multifocal applications. However, to the inventor's knowledge, no plano lenses have been made with a multifocal segment (such as a bifocal) and polarization. Thus, a need has arisen for polarized sunglasses and lenses that include multifocal segments and which are made from thin lens blanks.

Multifocal polarized sunglasses and lenses


LED systems and circuits for generating a driver output for powering one or more LED devices are provided. A dimmable driver circuit can include a controller configured to reduce output ripple current to reduce flicker over the dimming range of the LED system. The dimmable driver circuit can receive a dimming control signal (e.g. a 0V to 10V dimming control signal) over an isolated dimming interface to reduce leakage current at the dimming interface. In addition, a dual-switch flyback converter circuit can be employed to increase efficiency of the driver circuit as well as to reduce electromagnetic interference (EMI) with the LED devices, such as EMI resulting from differential mode noise.

LED lighting systems can include one or more LED devices that become illuminated as a result of the movement of electrons through a semiconductor material. LED devices are becoming increasingly used in many lighting applications and have been integrated into a variety of products, such as light fixtures, indicator lights, flashlights, and other products. LED lighting systems can provide increased energy efficiency, life and durability, can produce less heat, and can provide other advantages relative to traditional incandescent and fluorescent lighting systems. Moreover, the efficiency of LED lighting systems has increased such that higher power can be provided at lower cost to the consumer.
LED lighting systems typically include a driver circuit that can be configured to convert an input AC or DC power into a suitable driver output (e.g. driver current) for powering one or more LED devices. Driver circuits can include one or more control devices that control switching elements (e.g. transistors) to provide a desired driver output. Driver circuits can provide for dimming control of the LED devices, as well as for other functions, such as flicker reduction, power factor correction, and reduced electromagnetic interference.

Reduced flicker driver circuit for LED systems


A track and hold circuit is disclosed, including: a source follower coupled to a voltage supply; a MOS transistor with well structure, the MOS transistor having a gate terminal coupled to a gate terminal of the source follower, a drain terminal coupled to its body terminal and a source terminal of the source follower, and a source terminal coupled to a current source and an output terminal; a capacitive device having a terminal coupled to the gate terminal of the MOS transistor and another terminal coupled to a fixed voltage level; and a switch device coupled and disposed between an input signal and the gate terminal of the MOS transistor, wherein the switch device is controlled by a control signal.

1. Field of the Invention
The present invention relates to a track and hold circuit scheme, and more particularly, to a high-speed open-loop track and hold circuit with high linearity.
2. Description of the Prior Art
In an analog-to-digital converter (ADC), a high-speed track and hold circuit is one of the essential elements. The high-speed track and hold circuit in the prior art is realized by an open-loop scheme. Please refer to FIG. 1. FIG. 1 shows a diagram of a track and hold circuit 100 of a conventional open-loop scheme. As shown in FIG. 1, the track and hold circuit 100 is composed of a sampling network (which comprises a switch 110 and a capacitor 120), a source follower 130, and a current source 140. When the switch device 110 is turned on, the output voltage Vo will track the input voltage Vi, and when the switch device 110 is turned off, the input voltage Vi at that instance will be stored in the capacitor 120. After a settling time period, the output voltage Vo will catch up with the voltage value stored in the capacitor 120, and then remain unchanged. Although this scheme exhibits high-speed properties, the linearity of the transfer function of the source follower 130 will be adversely affected by the body effect and the channel length modulation effect, and consequently performance will decline significantly.
Please refer to FIG. 2. FIG. 2 shows a diagram of a track and hold circuit 200 of another conventional open-loop scheme. In the track and hold circuit 200, the source follower 230 is implemented using a MOS transistor with a well structure, such as an NMOS transistor with a deep N well structure, or a PMOS transistor with an N well structure. As shown in FIG. 2, the source follower 230 has a body terminal coupled to its source terminal and a current source 240, so as to eliminate the above-mentioned body effect. However, there will be parasitic capacitance generated at the PN junction, and the tracking speed of the track and hold circuit 200 will be reduced due to the existence of the parasitic capacitance loading. In addition, the linearity of the source follower 230 in the track and hold circuit 200 will also be affected by the channel length modulation effect and performance will decline greatly.


A method and a graphical user interface for processing of an object in light field data is provided. The method and graphical user interface may be used to remove an object or obstruction blocking another object or background of a captured scene. The method and graphical user interface may also be used for high precision edge detection in a light field image.

Light field imaging relates to images created using light field photography, wherein the light field data, i.e. angular information, position, and radiance of light rays from the photographed object or scene are accessible from the resulting light field image.
A standard 2D camera captures the light rays in two dimensions at plane f. The radiance and the position are recorded as pixel values and pixel position (coordinates x and y). However, the angles of the light rays are not recorded.
However, a light field camera records angular information as well as radiance and position. Having data describing light rays as vectors the rendering of the image may be processed in a way that is not possible with a standard 2D camera.
In essence a light field image comprises at least two subset images, wherein each subset image corresponds to a different viewpoint or direction of the imaged object or scene. Each subset image is captured by a separate lens. Hence, angular information is recorded in relations or differences among the subset images.
Various solutions to the problem of capturing lightfield data have been presented. A 3D camera having two lenses can be considered a simple lightfield camera as some angular data is preserved. Arrays of multiple cameras have been used. The plenoptic camera uses a single main lens and an array of micro lenses located in proximity to the image sensor. The plenoptic cameras can be divided into two categories; the focused and the unfocused type.
FIG. 1 schematically illustrates a known focused plenoptic camera, which utilizes uses an array of microlenses, Lm, to capture the light field image from an object r, wherein the object r if captured at the focal plane f would result in a sharp image (as for a standard 2D camera). The image sensor (not shown) is placed in the focal plane f2 of the microlens array Lm. The light paths for two micro lenses are shown. Both microlenses picture the same point of the object by using just a portion of the total cone of light representing that particular point. A typical focused plenoptic camera uses about 20-50 lenses to capture the light bundles from a single point. A typical design has several thousand microlenses. The depth of field of the individual subset images formed by the microlenses is very large as the focal length of the microlenses is very short compared with the main lens L.
An object that is moved closer or farther away from the camera will be imaged at a different focal plane f as can be seen in FIGS. 2a and 2b. Hence, the different angles of the light rays translate to a difference in position in the microlens images.
FIG. 3a illustrates a portion of a light field image, captured by a plenoptic camera, of the two objects "C" and "F" with "C" positioned closer to the camera than "F". Each hexagonal represents a subset image from a single microlens.
FIG. 3b shows two adjacent microlens subset images from the light field image of FIG. 3a. In FIG. 3c the two subset images has been superimposed in such a way that the letters C coincide. Note that the letter F is shifted sideways. This represents an image rendering with focus set at the distance of the letter C. In FIG. 3d the distance between the two images has been shifted to make the letter F sharp while the letter C is blurred. It can be seen from this example that a larger shift between the images (d) represents focus at closer distance from the camera. The out of focus portions in this example shows up as double strike letters. Normally when an image is rendered all microlens subset images are superimposed making out of focus objects appear smoothly blurred.
Another approach to rendering is to maintain the position of the individual microlens images but enlarging them until details in the desired focal plane coincide.
With current light field imaging techniques it is possible to focus, refocus, and change perspective. However an improved method, graphical user interface, and computer program product for processing of light field images allowing for new functionalities would be advantageous.

Method, graphical user interface, and computer program product for processing of a light field image


A memory apparatus is provided that includes a storage element configured to store and retain information based on the state of an electric resistance, and a circuit element connected in series to the storage element as a load. In the memory apparatus, a resistance value is set to one of a plurality of different levels by controlling a voltage or a current applied to the circuit element or the storage element upon the writing. The storage element includes levels having low resistance values and levels having high resistance values obtained after erasing, to each of which different information is allocated. One storage element may store information having a ternary value or more. When erasing the information from the levels excluding the level having the lowest resistance value, a level is initially changed to the level having the lowest resistance value, and subsequently changed to that having a higher resistance value.

The present disclosure relates to a memory apparatus in which a memory cell including a storage element capable of storing and retaining information based on a state of electric resistance.
Semiconductor non-volatile memories such as a flash memory are small in size and capable of retaining recorded data even when the power of the apparatus is turned off, and accordingly, the semiconductor non-volatile memories are widely used as recording mediums for recording moving images and sounds.
It is desired to increase recording capacity and increase recording density in non-volatile.
The non-volatile memories having larger recording capacity and higher recording density may include a non-volatile memory capable of multi-valued recording. That is, capable of storing data of 2 bits or more in one memory cell. The non-volatile memory capable of recording 2-bit data indicates a storage element forming a memory cell that can hold information in four recording states or levels.
Examples of a memory having such multi-valued technology include a flash memory or a resistance change type memory capable of recording information based on the change of a resistance value of a storage element.
The resistance change type memory that is capable of recording information by applying a voltage pulse to a storage element is disclosed in "Novel Colossal Magnetoresistive Thin Film Nonvolatile Resistance Random Access Memory (RRAM)", written by W. W. Zhuang et al., Technical Digest "International Electron Devices Meeting", 2002, page 193, for example. The resistance value of the storage element may be changed by changing the number of times to apply the voltage pulse to the storage element to realize multi-valued recording.
However, writing operation of a flash memory is performed by injecting electric charges stepwise into a terminal floating gate. If the flash memory is configured such that the flash memory may carry out multi-valued recording, longer time to realize multi-valued recording may be required as than when perfuming 1-bit recording (single value recording).
Further, when multi-valued recording is carried out using the resistance change type memory, there may also require longer time, because stepwise resistance change to realize multi-valued recording is controlled by varying the number of times to apply the voltage pulse to the terminal. Thus, increase an operation speed may also be difficult.
When recording information in the storage element capable of performing the multi-valued recording, a plurality of bits may be input and electric charges may be injected corresponding to a plurality of input bits or the voltage pulse may be applied the number of times. Thus, recording operations (electric charge injection or the number of times in applying the voltage pulse to the storage element) may preferably be performed corresponding to a relationship between a plurality of input bits and multi-valued information to be recorded may be performed using a simple circuit having excellent area efficiency.
Accordingly, a memory apparatus capable of carrying out multi-valued recording at high speed and including a driving circuit having a simple circuit with high area efficiency is desired.
Japanese Unexamined Patent Publication No. 2005-235360 discloses that a memory apparatus including a memory cell having a storage element and a circuit element such as a MIS (metal-insulator-semiconductor) transistor, and in which a resistance value of the storage element is controlled by controlling a voltage or current applied to the storage element or the circuit element so that multi-valued recording can be performed.
In the memory apparatus having this configuration, when "writing" is defined as an operation to change the resistance value of the storage element from high to low and "erasing" is defined as an operation to change the resistance value of the storage element from low to high, a resistance value obtained after writing (i.e., a state in which the resistance value is low) includes a plurality of levels so that multi-valued recording; that is, three or more values including a resistance value obtained after erasing (i.e., a state in which the resistance value is high) may be recorded.
However, in the memory apparatus having the above-mentioned configuration, when an erasing operation is carried out, the memory apparatus may provide routes for respective levels in order to shift the resistance value stored in the storage element from a plurality of levels of the resistance value obtained after erasing (e.g., three routes for three levels) to a high level so that erase characteristics in the respective routes may be different. Here, "erase characteristics" include a resistance value obtained after erasing, variability of the resistance value obtained after erasing, retention characteristics of recorded information (retention characteristics of resistance value) and the like.
If the resistance value obtained after erasing has large variability, when recorded information is read from the memory apparatus, recorded information cannot accurately be retrieved from the memory apparatus, thereby resulting in a read error.
If a voltage applied to the storage element to erase recorded information is not applied to all the corresponding routes, recorded information will fail to be erased.
Accordingly, it is desired that incompatibility of erase characteristics can be eliminated.


A system for making densified glass fiber pellets from chopped segments of multi-filament glass strand is described. The densified pellets may be advantageously produced by hydrating chopped glass strands and then pelletizing them by tumbling in a rotary drum, and densifying the resulting pellets by tumbling in a rotating zig-zag or undulating tube for a period of time sufficient to increase their density but insufficient to degrade the fibers to a point where composite articles formed from such pellets have lower tensile or impact strengths than comparable composite articles formed from unpelletized strand segments.

Chopped glass fibers are commonly used as reinforcement materials in thermoplastic articles. Typically, such fibers are formed by drawing molten glass into filaments through a bushing or orifice plate, applying a sizing composition containing lubricants, coupling agents, and film-forming binder resins to the filaments, gathering the filaments into strands, chopping the fiber strands into segments of the desired length, and drying the sizing composition. These chopped strand segments are thereafter mixed with a polymerized resin, and the mixture supplied to a compression- or injection-molding machine to be formed into glass fiber reinforced plastic articles. Typically, the chopped strands are mixed with pellets of a thermoplastic polymer, and the mixture supplied to an extruder wherein the resin is melted, the integrity of the glass fiber strands is destroyed and the fibers are dispersed throughout the molten resin, and the fiber/resin dispersion is formed into pellets. These pellets are then fed to the molding machine and formed into molded articles having a substantially homogeneous dispersion of the glass fibers throughout.
Unfortunately, however, chopped glass fibers made via such processes are typically bulky and do not flow well. Consequently, such fibers are difficult to handle and have been problematic in automated processing equipment.
One attempt at solving this problem has been to compact the chopped strands into denser rod-shaped bundles or pellets to improve the flowability of the chopped strands and enable the use of automated equipment to weigh and transport the glass fibers for mixing with the thermoplastic resins. Such a process is disclosed in U.S. Pat. No. 4,840,755, wherein wet chopped strands are rolled, preferably on a vibrating carrier, to round the strands and compact them into denser, cylindrically shaped pellets. While such methods and apparatus tend to provide denser, more cylindrically shaped pellets exhibiting better flowability, they are undesirably limited in certain respects.
For example, the pellet size and fiber content are generally limited by the size and number of fibers in the chopped strand, in that the process is designed to avoid multiple chopped strand segments from adhering together to form pellets containing more fibers than are present in a single chopped strand. Consequently, to obtain pellets having a suitable bulk density and a sufficient ratio of diameter to length to exhibit good flowability, the strand from which the segments are chopped usually must be formed of a large number of filaments. However, increasing the number of filaments required to be formed and combined into a single strand undesirably complicates the forming operation.
In an attempt to overcome these shortcomings, U.S. Pat. No. 5,578,535 discloses glass fiber pellets that are from about 20 to 30 percent denser than the individual glass strands from which they are made, and from about 5 to 15 times larger in diameter. These pellets are prepared by hydrating cut strand segments to a level sufficient to prevent filamentization but insufficient to cause the strand segments to agglomerate into a clump, and mixing the hydrated strand segments for a time sufficient to form pellets. Suitable mixing includes a process that will keep the fibers moving over and around one another, such as tumbling, agitating, blending, commingling, stirring, or intermingling.
Although the disclosed pellets can be made by such diverse mixing processes, it has been discovered that many of such processes are either too inefficient to be used commercially, or cannot be adequately controlled to produce a uniform pellet product that provides the resulting composite article with strength characteristics comparable to those made from nonpelleted chopped strand fibers. For example, the use of a modified disk pelletizer frequently results in excessive residence time of the formed pellets within the mixer, which results in degradation of the pellets due to the abrasive nature of glass fiber pellets rubbing against one another. Such pellet degradation ultimately reduces the strength characteristics of the molded articles made therewith.
Accordingly, a need exists for an efficient pellet-forming process that controllably yields a uniform glass fiber pellet product that provides strength characteristics equal to nonpelleted chopped strand fibers in composite molded articles. Such a need is fulfilled by the present invention, which is summarized and described in detail below.

System for preparing glass fiber pellets

Owens-Corning Fiberglas Technology, Inc.


In a method of analyzing a wafer sample, a first defect of a photoresist pattern on the wafer sample having shot regions exposed with related exposure conditions is detected. A first portion of the pattern includes the shot regions exposed with an exposure condition corresponding to a reference exposure condition and a tolerance error range of the reference exposure condition. The first defect repeatedly existing in at least two of the shot regions in a second portion of the pattern is set up as a second defect of the pattern. A first reference image displaying the second defect is obtained. The first defect of the shot regions in the first portion corresponding to the second defect is set up as a third defect corresponding to weak points of the pattern. The exposure conditions of the shot region having no weak points are set up as an exposure margin of an exposure process.

1. Technical Field
Example embodiments of the present invention relate to a method of analyzing a wafer sample. More particularly, example embodiments of the present invention relate to a method of analyzing a wafer sample for detecting a weak point of a pattern in an exposure process to set up a desired margin of the exposure process.
2. Discussion of Related Art
Semiconductor devices are generally manufactured through repeatedly performing separate processes that include a deposition process for forming a layer on a substrate, a chemical mechanical polishing (CMP) process for planarizing the layer, a photo process for forming a photoresist pattern on the layer, an etching process for patterning the layer into a pattern having electrical characteristics using the photoresist pattern, an ion implantation process for implanting ions into predetermined portions of the substrate, a cleaning process for removing particles from the substrate, an inspection process for inspecting defects of the layer and the pattern, and the like.
As a design rule of the semiconductor device decreases, a margin of an exposure process in the photo process also decreases and a step of detecting a weak point of a photoresist pattern becomes more important. In the conventional method of analyzing a wafer sample, the photoresist pattern is prepared on the wafer sample having a plurality of shot regions where patterns are repeatedly transcribed, and then the wafer sample is inspected with a high precision to detect defects of the photoresist pattern. The defects of the photoresist pattern repeatedly detected relative to each shot region are considered as the weak points of the photoresist pattern, and then the margin of the exposure process is adjusted in accordance with the number of the detected weak points of the photoresist pattern.
With a determination reference obtained from the repeatedly detected defects of the photoresist pattern, the number of weak points and the margin of the exposure process are changed. The determination reference, however, may unfortunately vary in accordance with the users. Although the weak points of the photoresist pattern and the margin of the exposure process are analyzed by one user, a consistent determination reference of analysis may not be ensured because the user subjectively determines the determination reference. Furthermore, the step of detecting the weak points of the photoresist pattern and a step of ensuring the margin of the exposure process may not be automatically carried out because of the subjective determination of the user.


Methods for hydrolyzing solid ungranulated lysophosphatidylcholine with phospholipase A2 are provided. Also disclosed are methods for making a lipid matrix of lysophosphatidylcholine, monoglyceride and fatty acid, and lipid matrices of particular structure.

Enzymatic conversion of phosphatidylcholine to lysophosphatidylcholine has been known since the early 1900's. Early investigations of the degradation of lecithin (phosphatidylcholine) by snake venom extracts demonstrated that the action of snake venom hemolysis is upon the lecithin portion of the cell membrane. In 1935, Hughes demonstrated that the hydrolysis of a unimolecular film of lecithin to lysolecithin (lysophosphatidylcholine) is dependent on factors such as pH, temperature and the surface concentration of the lecithin molecules. Packing of the lecithin molecules in the unimolecular layer greatly decreased the rate of hydrolysis. Hanahan demonstrated that an ether-soluble complex between egg phosphatidylcholine and phospholipase A2 resulted in the release of unsaturated fatty acid and lysophosphatidylcholine. Hydrolysis of phosphatidylcholine by phospholipase A2 could not be detected when 95% ethyl alcohol, chloroform or petroleum ether were used as solvents. Experiments performed by Dawson, reported in 1963, also found that phospholipase A2 hydrolyzed phosphatidylcholine to lysophosphatidylcholine and a single fatty acid molecule. Dawson determined that the enzymatic activity was dependent on the presence of calcium ions, and that the addition of ether or butanol stimulated the phospholipase A2 activity. British patent 1,215,868 to Unilever Ltd. described a further modification of the hydrolysis of phospholipid by phospholipase A2, conducting the reaction in the presence of fat (oils).
The processes of phosphatidylcholine hydrolysis disclosed in the prior art suffer from several shortcomings, including incomplete hydrolysis and production of unwanted side products in the hydrolysis reaction. The deficiencies of the prior art methods are severe because the presence of unreacted starting materials or unwanted side products represent an unacceptable level of contaminants in the final reaction product. These unwanted constituents must be removed from the reaction product in order to obtain the desired product, lysophosphatidylcholine, thus necessitating additional purification steps.
The prior art methods described above produce a maximal yield of lysophosphatidylcholine of approximately 70% of the starting phosphatidylcholine. Dawson showed that the addition of ether was required to stimulate the phospholipase A2 activity in the hydrolysis of phosphatidylcholine to the maximum yield of about 60-70%. The maximum yield of lysophosphatidylcholine was obtained when 8% diethyl ether (vol./vol.) in aqueous buffer was the reaction medium; using this reaction medium a two-phase system was observed. Dawson also found that 6% butanol (vol./vol.) could substitute for diethyl ether in the reaction medium to enhance yield of lysophosphatidylcholine, but ethanol and methylisobutylhexane were ineffective for increasing hydrolysis of phosphatidylcholine. Dawson concluded that the stimulatory effect of ether (or butanol) on hydrolysis of phosphatidylcholine was probably due to surface dilution of the closely packed phosphatidylcholine molecules oriented at the lipid interface and a removal of inhibitory fatty acid carbonyl groups from the interface. This conclusion was supported by evidence that addition of fatty acids inhibited the enzymatic hydrolysis of phosphatidylcholine (Dawson). Inhibition of the reaction by added fatty acid resulted either from inhibiting the removal of the fatty acid from the interface, or from formation of a calcium ion—fatty acid chelate, i.e., removal of Ca2+ ions required for phospholipase A2 activity. Dawson believed that the removal of calcium ions was the more likely explanation because the further addition of ether to form two phases and solubilize the additional fatty acid did not promote hydrolysis of phosphatidylcholine, whereas increasing the calcium concentration ten fold did partially relieve the inhibition. It was also shown that the phospholipase A2 enzyme purified from cobra venom was dependent on the presence of calcium ions for hydrolysis activity. The requirement for calcium ions in the hydrolysis reaction by phospholipase A2 and the association of calcium ions with fatty acids released by the hydrolysis of phosphatidylcholine is well known in the art (Novo Nordisk).
Yesair described methods for the preparation of mixed lipid particles useful in the delivery of drugs and for providing readily absorbable calories to an individual (U.S. Pat. Nos. 4,874,795 and 5,314,921). These methods involve the mixing of lysophosphatidylcholine, monoglyceride and fatty acid in specific molar ratios. Although easily performed, these previous methods use costly, isolated, highly purified lysophosphatidylcholine, thus adding to the expense of the final mixed lipid particle product.
Yesair subsequently described methods by which phosphatidylcholine is more efficiently converted to lysophosphatidylcholine (U.S. Pat. No. 5,716,814). The described methods result in more efficient use of phosphatidylcholine and yield fewer unwanted side products (such as glycerophosphatidylcholine) and contaminants (such as unhydrolyzed phosphatidylcholine) in the final reaction product. The use of the described methods in which the end products are in a more pure form results in substantial cost savings and time savings due to a reduced need for the purification of the end products. These methods require, however, the use of partially purified phosphatidylcholine in granulated form. While ability to use of this form of phosphatidylcholine represents an improvement over prior methods, there remains a need to reduce the cost of production of lysophosphatidylcholine. A method which utilizes less highly processed phosphatidylcholine as a starting material would reduce the need for the use of a relatively more expensive granulated preparation of phosphatidylcholine as a starting material, thus reducing the overall costs for the final lysophosphatidylcholine product and for mixed lipid particle products prepared using lysophosphatidylcholine.

Modification of solid 3-sn-phosphoglycerides


An active matrix substrate includes an insulative plate; a plurality of switching elements arranged in a matrix on the insulative plate; a plurality of gate signal lines for controlling the switching elements; a plurality of source signal lines for providing data signals to the switching elements, the source signal lines being perpendicular to the gate signal lines; and a plurality of pixel electrodes respectively provided above and in electric connection with drain electrodes of the switching elements. At least one of the source signal lines and the drain electrodes include at least a transparent conductive layer, a first metal layer and a second metal layer.

1. Field of the Invention
The present invention relates to an active matrix substrate usable in, for example, a liquid crystal display device.
2. Description of the Related Art
FIG. 9 is a partial equivalent circuit diagram of a conventional active matrix substrate 500.
The active matrix substrate 500 shown in FIG. 9 includes a transparent insulative plate 101 formed of glass or the like, a plurality of gate signal lines 102 formed of tantalum or the like, a plurality of storage capacitance common lines 103 for forming a storage capacitance Cs, and a plurality of source signal lines 104. The gate signal lines 102, the storage capacitance common lines 103 and the source signal lines 104 are provided on the transparent insulative plate 101. The source signal lines 104 are arranged perpendicular to the gate signal lines 102 and the storage capacitance common lines 103. The source signal lines 104 have a two-layer structure including a metal layer and an ITO (indium tin oxide) layer. The active matrix substrate 500 further includes a plurality of pixel electrodes 105 arranged in a matrix and a plurality of thin film transistors (hereinafter, referred to as a "TFT") 106 acting as switching elements. The pixel electrodes 105 are connected to the gate signal lines 102 and the source signal lines 104 through the TFTs 106. In the case where the active matrix substrate 500 is included in a transmissive device, the pixel electrodes 105 are formed of a transparent conductive material such as, for example, ITO. In the case where the active matrix substrate 500 is included in a reflective device, the pixel electrodes 105 are formed of aluminum or the like.
The active matrix substrate 500 further includes, in a peripheral area thereof, gate signal line terminals 107 for inputting synchronization signals, storage capacitance common line terminals 108, and source signal line terminals 109 for inputting video signals. Although not shown in FIG. 9, the terminals 107, 108 and 109 include a transparent conductive layer for covering an underlying metal layer for the purpose of preventing the underlying metal layer from being oxidized. The transparent conductive layer is formed of, for example, ITO, which is used for forming the pixel electrodes 105 and the source signal lines 104.
FIG. 10 is a plan view of one pixel area of the active matrix substrate 500 shown in FIG. 9, from which an interlayer insulative layer and the pixel electrode 105 are omitted for clarity. FIG. 11 is a plan view of one pixel area of the active matrix substrate 500 shown in FIG. 9. FIG. 12 is a cross-sectional view of the one pixel area shown in FIG. 11 taken along line XII--XII in FIG. 11. FIG. 13 is a cross-sectional view of a part of the one pixel area shown in FIG. 11 taken along line XIII--XIII in FIG. 11. As shown in FIG. 11, a peripheral area of the pixel electrode 105 overlaps the gate signal lines 102 and the source signal lines 104. In FIG. 13, an interlayer insulative layer and the pixel electrode 105 are omitted for clarity. The following description will be provided regarding one pixel area for simplicity.
Referring to FIGS. 12 and 13, the gate signal line 102 including a gate electrode 116 and a storage capacitance common line 103 are provided on the transparent insulative plate 101. A gate insulating layer 112 is provided on the transparent insulative plate 101 so as to cover the gate signal line 102 including the gate electrode 116 and the storage capacitance common line 103.
As shown in FIG. 13, a semiconductor layer 113 is provided on the gate insulating layer 112 so as to overlap the gate electrode 116. An n.sup.+ silicon layer 114 and an n.sup.+ silicon layer 115 are provided on the semiconductor layer 113 with a gap interposed therebetween. A source electrode 117 and a drain electrode 110, each formed of an ITO layer 126 and a metal layer 125, are provided on the n.sup.+ silicon layers 115 and 114, respectively. The TFT 106 includes the gate electrode 116, the semiconductor layer 113, the n.sup.+ silicon layers 114 and 115, the source electrode 117 and the drain electrode 110. The gap between the n.sup.+ silicon layers 114 and 115 corresponds to a channel region of the TFT 106.
As best shown in FIG. 11, the ITO layer which is a part of the drain electrode 110 is extended in a direction perpendicular to the gate signal line 102 and the storage capacitance common line 103 and then further extended in a direction overlapping the storage capacitance common line 103. The extended part of the ITO layer acts as a connecting electrode 127. The part of the connecting electrode 127 which overlaps the storage capacitance common line 103 acts as a storage capacitor electrode 127a.
As shown in FIG. 12, the interlayer insulative layer 118 is provided on the gate insulative layer 112 so as to cover the elements provided on the gate insulative layer 112. The pixel electrode 105 is provided on the interlayer insulative layer 118. The interlayer insulative layer 118 has a contact hole 111 provided therethrough. The connecting electrode 127 is electrically connected to the pixel electrode 105 through the contact hole 111. The drain electrode 110 (FIG. 13) is electrically connected to the pixel electrode 105 through the connecting electrode 127. A portion where the storage capacitor electrode 127a, the gate insulative layer 112 and the storage capacitance common line 103 overlap one another acts as a storage capacitor.
In the above-described structure, the pixel electrode 105 overlaps the source signal line 104 due to the interlayer insulative layer 118 provided therebetween. Accordingly, the aperture ratio is raised, and the leak between the source signal line 104 and the pixel electrode 105 is reduced.
A method for producing the conventional active matrix substrate 500 will be described with reference to FIGS. 14A through 14E and 15A through 15E.
FIGS. 14A through 14E are cross-sectional views illustrating a process for producing the TFT 106. FIGS. 15A through 15E are cross-sectional views illustrating a process for producing the gate signal line terminal 107 and the storage capacitance common line terminal 108. Since the terminals 107 and 108 have a substantially identical structure, the gate signal line terminal 107 will be described as an example.
First, as shown in FIGS. 14A and 15A, a metal layer is formed on the transparent insulative plate 101 and patterned into the gate signal lines 102 including the gate electrode 116.
As shown in FIGS. 14B and 15B, the gate insulative layer 112 is formed on the transparent insulative plate 101 so as to cover the gate electrode 116 and the gate signal line 102. Then, as shown in FIG. 14B, the semiconductor layer 113 and an n.sup.+ silicon layer 124 are formed sequentially on the gate insulative layer 112.
As shown in FIG. 15C, a contact hole 112a for forming a connecting portion (represented by reference numeral 130 in FIG. 15D) of the gate signal line terminal 7 is formed in the gate insulative layer 112.
As shown in FIG. 14C, the ITO layer 126 and the metal layer 125 are formed on the n.sup.+ silicon layer 124. The ITO metal layer 125 and the ITO layer 126 are separately patterned by photolithography or the like in this order. As a result, the source electrode 117 and the drain electrode 110 are formed as shown in FIG. 14D, and the connecting portion 130 is formed of the ITO layer 126 which is formed as shown in FIG. 15D as a result of the removal of the metal layer 125. As best shown in FIG. 13, the ITO layer 126 is patterned to extend on the gate insulative layer 112 from the drain electrode 110 in a direction perpendicular to the gate signal line 102 (FIG. 11) and then in a direction overlapping the storage capacitance common line 103 so as to act as the connecting electrode 127.
For the TFT 106, the ITO layer 126 is provided for preventing line disconnections and for protecting the underlying layers against etching which is performed on the metal layer 125. The connecting electrode 127 is formed only of the ITO layer 126 in order to raise the aperture ratio and also obtain ohmic contact with the pixel electrode 105.
Then, as shown in FIG. 14E, an area of the n.sup.+ silicon layer 124 corresponding to a channel region in the semiconductor layer 113 is removed, thereby forming the n.sup.+ silicon layers 114 and 115. The interlayer insulative layer 118 is formed on the gate insulative layer 112 so as to cover the elements which are formed on the gate insulative layer 112 except for the area where the terminals 107, 108 and 109 are formed. A transparent conductive layer, for example, an ITO layer is formed on the interlayer insulative layer 118 (FIG. 14E) and on the gate insulative layer 112 so as to cover the connecting portion 130 (FIG. 15E). The ITO layer on the interlayer insulative layer 118 is patterned to form the pixel electrode 105 (FIG. 14E) and also a transparent conductive layer 105a (FIG. 15E).
An alignment layer is formed when necessary. Thus, the active matrix substrate 500 is completed. A liquid crystal display device, for example, is produced by combining the active matrix substrate 500 with a counter substrate (not shown) and injecting a liquid crystal material into the gap between the two substrates and sealing the gap.
According to the active matrix substrate 500 having the above-described structure, the drain electrode 110 which is connected to the pixel electrode 105, the connecting electrode 127 extended from the drain electrode 110, and the connecting portion 130 of the terminals 107 and 108 are formed in the same step as the source signal line 104 including the source electrode 117. However, the connecting electrode 127 and the connecting portion 130 are formed of only the ITO layer 126. Accordingly, the metal layer 125 and the ITO layer 126 need to be separately patterned by photolithography or the like. Thus, the number of production steps is increased, and defective photo-patterning may disadvantageously occur. Consequently, there is an undesirable possibility of source-drain leak. As a result, the production yield is reduced.
In order to reduce the number of steps of performing photolithography so as to raise the production yield even though the aperture ratio is slightly lowered, it is conceivable that the connecting electrode 127, the source signal line 104, and the connecting portion 130 of each of the terminals 107 and 108 are formed of the metal layer 125 and the ITO layer 126.
In such a structure, however, a contact deficiency occurs between the pixel electrode 105 and the connecting electrode 127 and between the transparent conductive layer 105a and the connecting portion 130. Such a contact deficiency occurs because a surface of the metal surface 125 is oxidized by ashing which is performed before the pixel electrode 105 and the transparent conductive layer 105a are formed or by formation of the pixel electrode 105 and the transparent conductive layer 105a.
As a result, the display quality of a display device including the active matrix substrate 500 is significantly reduced. In addition, a signal voltage needs to be raised in order to compensate for the voltage drop which is caused by an increase in the contact resistance. The rise in the signal voltage increases the power consumption.

Active matrix substrate with multi-layer signal lines and/or electrodes


A method of recording information in a card and reading the information therefrom and recording an image in the card by using a card reader and writer, which card has a rewritable information recording portion, and a rewritable image recording portion employing a reversible thermosensitive recording material.

The card comprising a rewritable information recording portion which utilizes the magnetic memory, IC chip, or optical memory has recently spread. Information is written in such a card and read therefrom using a card reader and writer equipped with a recording mechanism of recording the information in the card and a reading mechanism of reading the information recorded in the card. As this kind of card, in particular, a telephone card, a prepaid card, a cash card and the like have widely spread. In the case of any cards, however, the information recorded in the information recording portion can be recognized only through a display portion of a reading apparatus (on the side of the card reader and writer).
Recently attention has been paid to a reversible thermosensitive recording material capable of temporarily carrying out the image formation (recording) thereon and erasing the image therefrom when the image becomes unnecessary, and repeating such recording and erasure. As a representative example, there is known a reversible thermosensitive recording material in which an organic low-molecular-weight material such as a higher fatty acid is dispersed in a matrix resin such as a vinyl chloride resin (Japanese Laid-Open Patent Application 55-154198 and the like).
However, such a conventional reversible thermosensitive recording material (which will hereinafter also be referred to as "a recording material" simply) has the drawback that the surface is rubbed with the application of heat thereto and then scratched while images are formed and erased repeatedly by the application of heat, especially by use of a thermal head. When the occurrence of the scratch becomes serious, images cannot be formed uniformly.
The inventors of the present invention have proposed to provide a protective layer on the surface of the above-mentioned recording material in order to decrease the scratches on the surface caused by the use of the thermal head (Japanese Laid-Open Patent Application 63-221087, Japanese Laid-Open Patent Application 63-317385, Japanese Laid-Open Patent Application 2-566 and so on). However, it is hard to assert that the provision of the protective layer on the surface of the conventional recording material is quite enough when the recording and erasure are repeated many times.
In addition, the previously mentioned recording material in which the organic low-molecular-weight material is dispersed in the matrix resin has the drawback that when there is employed a heating system of simultaneously applying heat and pressure, such as the thermal head, the particles of the organic low-molecular-weight material tend to aggregate, thereby decreasing the contrast (the degree of milky whiteness) as the number of recording times is increasing.
In fact, such a recording material is put to practical use as a point card (with no information recording portion such as the magnetic memory) on the assumption that it is not repeatedly used so many times. Such a card is used in the following manner so far as the inventors of the present invention know:
Every time a card holder makes a purchase, a mark of .asterisk-pseud. is overwritten successively depending on the point corresponding to a predetermined amount of money. When the predetermined points are saved, the exchange of a commodity equivalent to the predetermined sum of money becomes possible. The card will be subjected to entire erasure when the predetermined points are awarded, and the card can be used again in the above-mentioned manner. However, according to such a manner, the card holder cannot know instantly how many points he has been awarded at present, and in addition, the card cannot be used for other purposes such as transmission of various information because the mark of .asterisk-pseud. is merely overwritten, so that the card is lacking in convenience.
It is therefore an object of the present invention to provide an information and image recording method, with the life of a card which comprises a rewritable information recording portion and an image recording portion comprising a reversible thermosensitive recording material being drastically increased.
Another object of the present invention is to provide an information and image recording method, capable of readily recognizing the information recorded in the image recording portion comprising the reversible thermosensitive recording material.

Method of recording information and images in card having information recording portion and image recording portion


A wood material board hot-pressing system with a primary circuit includes a supply pipe for discharging of hot heat transfer fluid from a heat generator and a return pipe for supplying cooled heat transfer fluid to the heat generator. A secondary circuit features a pressing device for pressing wood material boards. A supply channel supplies heat transfer fluid to the pressing device and a return channel returns cooled heat transfer fluid to the primary circuit. A controlling device contains a control valve and is configured to control a flow of heat transfer fluid from the primary circuit to the secondary circuit. A secondary circulation pump with variable output is set up to circulate the heat transfer fluid in the secondary circuit. The controlling device features a heat output recording device and is configured to automatically control a level of heat output (P) supplied to the pressing device.

1. Field of the Invention
The invention refers to a wood material board hot-pressing device with (a) a primary circuit, which features a supply pipe for the discharging of hot heat transfer fluid from a heat generator and a return pipe for the supplying of cooled heat transfer fluid to the heat generator, (b) a secondary circuit, which features a pressing device for the compression of wood material boards, a supply channel for the supplying of heat transfer fluid to the pressing device and a return channel for the returning of cooled hear transfer fluid to the primary circuit, and (c) a controlling device which contains a control valve and is configured to control a flow of heat transfer fluid from the primary circuit to the secondary circuit, specifically from the supply pipe to the supply channel.
According to a second aspect, the invention refers to the operation process for such a wood material board hot-pressing device.
2. Discussion of Background Information
Such wood material board hot-pressing devices are used in order to produce by means of compression a wood material board from dried wood particles mixed with a glue. Such hot-pressing devices are set up to run continuously, i.e. they are continuously loaded with wood particles mixed with glue and produce a continuous flow of wood material boards.
Usually, wood material board hot-pressing devices are stopped only if a defect is present or if the device is to be readjusted to facilitate the production of wood material boards with different dimensions. With each restart there is a warm-up period in which no usable product is produced, only waste. If the pressing device is frequently restarted, this can thus lead to a substantial amount of waste.

This patent is subject to a terminal disclaimer.

Wood material board hot-pressing device and operation process for such a device


A vacuum transport system suited to moving FOG-laden water. The system includes a first reservoir and at least one vacuum pump in fluid communication with the first reservoir and operable to produce a vacuum within the first reservoir. A first accumulator is positioned to collect FOG-laden water from a first FOG-laden water source. A first valve is operable to selectively provide fluid communication between the first accumulator and the first reservoir. FOG-laden water can be drained from the first reservoir into a grease interceptor disposed in the building exterior.

The present invention relates to a system and method for draining waste in a plumbing system. More particularly, the present invention relates to a system and method for draining gray water waste and FOG-laden waste in a plumbing system using a vacuum system.
Wastewater is generally grouped into one of several classifications based on the contaminant contained within the water. Gray water generally includes water that drains through floor drains, food preparation sinks, and the like. FOG-laden water generally includes contaminates that are often referred to as FOG (fats, oil, and grease). Generally, gray water can be directed to a sewer or septic system without additional treatment. FOG-laden water is generally treated to remove some or all of the FOG before it is directed to the sewer or septic system.
Various types of drainage systems are used to direct waste from a source, or a plurality of sources, to a common collection point. For example, gravity feed systems are commonly used in residential and commercial buildings to direct waste to the desired collection point. In gravity drain systems, gravity provides the motive force to move the waste from the source(s) to the collection point. Because gravity is the main motive force, the pipes between the source(s) and the collection point must slope down toward the collection point to maintain the desired flow. However, as the pipes of a gravity system become worn, corroded, roughened, or clogged, gravity alone is sometimes insufficient to move the waste. The requirement that the pipes slope also requires careful planing prior to, and during the construction of a building to assure that the pipes are properly located. This extensive pre-planning makes the addition of pipes or new sources to a completed building difficult. For example, if a store owner wished to move a source of waste water (e.g., clear waste, condensate, gray waste, and the like) from a first location to a second location, drain pipes would have to be positioned in the floor beneath the second location. This may require demolition of the floor, closure of the store, and other activities that are inconvenient and perhaps unsafe.
Vacuum drainage systems offer an alternative to gravity systems. Vacuum systems use a combination of gravity and vacuum to draw waste from the source, or sources, to a collection point. Because the main motive force is vacuum (pressure) rather than gravity, the orientation of the pipes is less significant to the operation of the unit. As such, pipes can be positioned above the source of waste if desired.


A television multiplexing and transmission system and method, which is using certain portions of the standard television channel-bandwidth to superimpose additional information by phase-modulating said information using precisely-derived frequency carriers combined with reference frequencies and injecting said phase modulated electronic signals at amplitudes below the standard minimum detectable signal without affecting the simultaneous orderly operation of the same standard television channels into which the additional information is multiplexed, which system may be used to simultaneously transmit to a plurality of users various data in response to their corresponding queries, with particular applications to CATV systems, comprising a user data unit, a multiplexing and transmission unit and a alternate frequency unit.

This invention relates generally to television systems and networks and more particularly to those cable-television networks and/or wireless television networks in which digital data as well as other information is transmitted through the network, combined with or superimposed on standard television signals so as to make more efficient and economical utilization of available communication channels.
The development and utilization of communication networks such as the Internet has been constrained by the bandwidth limitations of telephone networks. Consequently, the utilization of cable TV networks known as CATV as a means of carrying Internet information has been introduced so as to enable to transmit data as well as video signals of high quality. For example, EP-A-0 742 658, JP-A-04 196792, JP-A-11 041213 and EP-A-0 577 351 disclose various methods for utilizing cable TV for the transmission of additional data. JP-A-04 196792 discloses a CATV subscriber system transmission method utilizing frequency multiplexing between an incoming and an outgoing signal to and from an off premise device. JP-A-11 041213 discloses a conversion circuit converting Internet based data requests to suitable CATV transmission. EP-A-0 577 351 discloses a television signal processing system, the system assigns plural data to the amplitude or phase information in the frequency domain at the transmission side. However, present products enabling Internet users to utilize the advantage of higher-bandwidth CATV are constrained due to the various design limitations of present TV equipment. One of the principal limitations is due to the fact that TV channels were designed to transmit information from a single source to many users. Such a ubiquitous system can hardly allow for the transmission of specific messages intended for review or processing by individuals. The relative bandwidth allowed for applications, other than standard TV transmission, is small compared to the bandwidth reserved for said standard channels, i.e. 30 to 40 Mhz out of 500 to 750 Mhz. One way to overcome this bandwidth limitation and the unilateral nature of TV channels is to combine CATV and additional telephone lines so as to enable the user to send information via the telephone line while receiving information on the cable TV. One example is disclosed in EP-A-0742 658 disclosing a system which considers the multiple channels as one unit and managing such unit via a bandwidth management unit. Another example may be the so-called WebTV system. However, this hybrid solution is forcing the user to connect his terminal both to the TV line as well as to the telephone line, while the "downstream" constraints still exists.
Other ways to use CATV networks for internet applications have been suggested according to which certain channels are dedicated to Internet traffic thereby preventing their simultaneous use for conventional or other television programs, which may reduce the economic effectiveness of the given CATV network.
Furthermore, it is anticipated that in the future, the requirement for bandwidth within interactive networks, enabling users to feed back various queries or data while receiving individual responses through the TV network will increase.
In an effort to overcome constraints inherent to other techniques that have been used for interactive utilization of communication networks such as the Internet in the TV or CATV environments, this invention is proposing methods to send data within the standard TV channels so that facilities already existing for transmission of "downstream" composite TV signals may simultaneously be utilized for carrying additional individual information by superimposing corresponding additional signals on the standard existing TV composite signals without deteriorating the appearance of the video or audio components of said standard TV signals.

Television multiplexing and transmission system and method


An external air baffle nozzle has a top surface, a bottom surface, and a pair of sidewalls separating the top surface from the bottom surface. An end of the pair of sidewalls, an end of the top surface and an end of the bottom surface define an inlet. An opposite end of the pair of sidewalls, an opposite end of the top surface, and an opposite end of the bottom surface define an outlet. The outlet has a smaller cross section than a cross section of the inlet.

Distributed network systems have been widely adopted with the emergence of the cloud for computing applications. Network systems encompass numerous connected devices including servers, switches, and other devices that exchange data. Faster and denser electronic components have been used in network devices to address the need for increased data capability and speed.
Network devices such as servers generate an enormous amount of heat due to the operation of the internal electronic devices such as transceivers, controllers, processors, and memory. Overheating from the inefficient removal of such heat has the potential to shut down or impede the operation of such devices. Thus, network system devices, such as servers, are designed to rely on air flow through the interior of the system device to carry away heat generated from electronic components. Air flow is often generated by a fan system that accelerates air flow through the system device. The generated air flow thus carries collected heat away from the network system devices and out of the device. The generated air flow is most efficiently utilized if it is largely focused toward the network system devices and not dissipated throughout the rest of the system device.
Thus, there is a great need for providing a device and method that solves the above and other problems, including, for example, an air baffle nozzle that improves air flow for an electronic component.


A method for determining an accurate phase difference between a phase of a light beam in each of two light paths, the two light paths being in a rotating interferometric fiber optic gyro, by measuring a first phase difference due to angular velocity of the rotating interferometric fiber optic gyro, flipping axes of rotation of photons in the light loops of the rotating interferometric fiber optic gyro, and measuring a second phase difference due to angular velocity of the rotating interferometric fiber optic gyro.

A planar rotating interferometric fiber optic gyro is designed to produce an accurate phase difference, DeltaPhi(t), between a counter clock-wise light loop and a clock-wise light loop, for a gyro rotation rate OMEGA. However, a planar rotating interferometric fiber optic gyro can produce an erroneous phase difference, DeltaPhi′(t), due to temperature, mechanical effects or other environmental influences. DeltaPhi′(t) is a measured phase difference that is not the accurate phase difference, DeltaPhi(t).
DeltaPhi′(t) is a measured phase difference over time between two light loops in the rotating interferometric fiber optic gyro. DeltaPhi′(t) occurs when a fiber optic gyro is experiencing an applied rotational velocity OMEGA.
A variation between a measured phase difference, DeltaPhi′(t), and an accurate phase difference, DeltaPhi(t), is gyro phase drift. Such gyro phase drift can be due to a temperature variation in the rotating interferometric fiber optic gyro, or due to a mechanical variation in the rotating interferometric fiber optic gyro. The amount of gyro phase drift can slowly change with time.
Gyro phase drift is evidenced as a difference value DeltaPhi(t)−DeltaPhi′(t) or DeltaPhi′(t)−DeltaPhi(t) for an applied planar rotational velocity, OMEGA, of an interferometric fiber optic gyro.
An erroneous phase difference, DeltaPhi′(t), will cause a planar rotational velocity measurement, OMEGA', to be made by the interferometric fiber optic gyro.
Laser light, in each of the two light beams, has the same phase Phi(t) as the laser light enters the single optical fiber cable. The phase difference between the two exiting counterrotating light beams is detected in the interference pattern. Ideally, an accurate phase difference, DeltaPhi(t)=(Phi1(t)−Phi2(t)), or Delta Phi(t)=(Phi2(t)−Phi1(t)), should be produced due to a counterclockwise or clockwise planar angular rotational velocity of the fiber optic gyro.
Gyro phase drift changes with time, and tends to be slowly continuous, in a mathematical sense. The present invention uses the continuity of slow gyro phase drift changes to eliminate the overall effect of gyro phase drift.

Method and assembly for an interferometric fiber optic gyro

The United States of America as represented by the Secretary of the Navy


A communication system is designed to exchange messages between a plurality of paging receivers each having a transmission section. One of the paging receivers transmits a question message and a plurality of answer contents to the question message to a paging receiver group constituted by the remaining paging receivers. When answer messages are returned from the paging receiver group which has received the question message and the answer contents, the paging receiver totalizes the answer messages, and displays them on a liquid crystal display panel, together with the question message.

1. Field of the Invention
The present invention relates to a data communication system applied to a data communication terminal such as a paging receiver, and a data communication terminal using the system.
2. Description of the Related Art
In a paging system based on the POCSAG scheme, a common address data is stored in the ID-ROMs of a plurality of paging receivers so that a caller can perform simultaneous paging to a plurality of subscribers who are carrying paging receivers having the common address data by transmitting this address data from a telephone terminal through a switching center. This simultaneous paging method is called a group call method among those skilled in the art and is used as a paging service.
If, therefore, a caller transmits a question message requesting an answer, as message data, following the common address data by the group call method using a computer terminal connected to a telephone line, a plurality of subscribers who are carrying paging receivers which have simultaneously received this question message can prepare answers to the received question message, and can return the answers to the computer terminal which has sent the question message.
In transmitting a question message by using the group call and obtaining a plurality of answers in this manner, it is difficult for the user of the computer terminal, which has sent the question message, to specify a paging receiver (subscriber) in the group every time an answer is obtained. In addition, when a plurality of question messages are transmitted to the same group, it is difficult to discriminate a specific question message to which a given answer corresponds.
The exchange of a question message and answers in a group by the group call method in such a system is effective for only very limited purposes. That is, this method is not very convenient.
As a new paging service which replaces the conventional POCSAG scheme, a paging service based on an advanced radio paging system called RCRSTD-43 will be put into practice in Japan.
This paging system will be briefly described with reference to FIGS. 1A to 1C.
FIG. 1 shows a scheme of signal transmission which is employed in the above advanced radio paging system. The format (A) in FIG. 1 shows a data configuration. The format (B) in FIG. 1 shows a cycle configuration. The format (C) in FIG. 1 shows a frame configuration.
The data configuration (A) in FIG. 1 consists of 15 cycles which are numbered "#0" to "#14". The 15 cycles are transmitted at one-hour intervals. The cycle configuration (B) in FIG. 1 consists of 128 frames which are numbered "#0" to "#127". The 128 frames are transmitted at four-minute intervals. The frame configuration (C) in FIG. 1 consists of eight pieces of information, i.e., a first synchronous portion S1, frame information FI, a second synchronous portion S2, block information BI, an address field AF, a vector field VF, a message field MF, and an idle block IB.
In this frame configuration, the eight pieces of information define the following contents.
More specifically, the first synchronous portion S1 defines the frame type (the modulation scheme and transmission rate) of this frame. The frame information FI defines the frame number of the frame, a cycle number at which the frame is present, and the like. The second synchronous portion S2 defines timing information which is used to establish a reception timing in a called paging receiver in transmitting data in accordance with the frame type defined by the first synchronous portion S1. The block information BI defines word numbers at which the address field AF and the vector field VF respectively start, and the necessary numbers of words. The address field AF defines ID data, specifically address data, stored in each called receiver. The vector field VF is defined in a one-to-one correspondence with the address field AF. The vector field VF defines a word number at which the message field MF is started, the necessary number of words, a vector type (tone only, a numerical message, and the like) specifying a message to be transmitted. The message field MF is used to store message data to be actually transmitted. The idle block IB is an unused block, in which a pattern of "1"s or "0"s is set.
According to paging services using the above advanced radio paging system, therefore, various services which cannot be provided by the conventional POCSAG scheme can be realized.
As one of the services, a service based on a group call method using temporary address data can be realized, in addition to a service based on the conventional group call method using group address data.
In this method, a plurality of paging receivers which do not share group address data are simultaneously paged. The method will be described below.
1. A caller designates the group call mode using temporary address data and transmits the call numbers of a plurality of paging receivers to be called and a common message to a center (paging control center).
2. When the group call mode is designated by the caller using the temporary address data, the center transmits address field AF contents address data for calling the designated paging receivers thereto, together with vector field VF contents vector data of a simplified instruction vector type which defines the temporary address data and a frame number at which the temporary address data is stored.
3. Upon terminating this vector data, each of the called paging receivers writes the temporary address data in an address register in a decoder, and also writes the frame number data at which the temporary address data is stored in a frame register, thereby controlling the reception frame timing. At the designated frame number, each paging receiver detects the temporary address data in accordance with the address field AF.
4. When each paging receiver detects the temporary address data at the designated frame number in accordance with the address field AF, the receiver receives the common message stored in the successive message field MF, notifies that the message is terminated, and displays it.
According to the above method, therefore, a plurality of paging receivers to be subjected to simultaneous paging need not have common address data. That is, a more convenient group call method can be realized.
In the above method, however, the following problem is posed.
When a caller designates the group call mode using temporary address data, he/she must input all the call numbers of a plurality of paging receivers to be called through a telephone terminal connected to the center. If the caller is to use a push-phone through a public telephone network, a cumbersome input operation is required. The caller is therefore liable to make a mistake.
The present invention has been made in consideration of the above problem, and has as its object to provide a data communication system in which a caller can selectively perform batch transmission of a question message to a plurality of callees and totalize a plurality of answers to this question in a readable form, and a data communication terminal using the system.

Data communication system and data communication terminal applied thereto


A Z-fold convertible top has a frame supporting a textile cover. The frame includes support in the form of at least one of a pair of pivoted rails rigidly mounted to a bow, stabilizing other pivoted rails. The stability may be employed to displace a quarter window with the rail in a manner that provides a compact top stack packaged in the vehicle body. The stability is also employed to coordinate sealing engagement of the quarter window with a cloth control link pivoted to the vehicle body ground, but displacing the cloth away from the window during retraction. A worm link may enhance interaction between the cloth control link and the rail supporting a quarter window.

Convertible tops for vehicles include a frame having articulated links on lateral sides of the vehicle. A plurality of bows are covered by a flexible fabric covering and supported by the articulated links that generally pivot about pivot pins or joints that have a transverse pivot axis. The convertible top is displaced to and between an extended position covering the vehicle passenger compartment, and a retracted position. The textile covering is folded with the frame when released from taut engagement with the frame in a closed position in which a front bow may be releasably attached to a windshield header, and a rear bow retains the top against the vehicle body.
A storage area rearward of the passenger seating receives the convertible top frame including bows and articulating links when the top is retracted. During displacement, the numerous connections in the frame may require tolerances to accommodate the stacking, and the frame does not rigidly support structures such as windows that may also serve to enclose the passenger compartment.
Typically, the displacement of windows that serves to complete the enclosure are separately supported and displaced by mechanisms carried in the vehicle body. The combinations of structures further reduce interior space. Moreover, separate mechanisms render the sealing of the top more difficult in the closed position, and may interfere with climate control in the interior and the overall aesthetic appearance of the vehicle's exterior.

Z-fold convertible top supporting retractable quarter window


In one embodiment, a method is contemplated. The method includes creating a copy of a volume, wherein the copy corresponds to a first point in time. Write operations to the volume are logged separate from the volume. The method also includes recovering a state of the volume to a second point in time subsequent to the first point in time using the copy of the volume from the first point in time and at least a subset of the write operations from the log. The subset of write operations occurs subsequent to the first point in time and prior to the second point in time. In some embodiments, an end marker may be included in the log, and recovery to a write operation that is indicated as the end of a transaction (by the end marker) may be performed.

1. Field of the Invention
This invention is related to the field of volume management on storage devices and, more particularly, to recovering a previous state of a volume.
2. Description of the Related Art
Computer systems have been responsible for large productivity increases, as well as providing new and exciting functionality for users to experience in both work and leisure capacities. Crucial to the usefulness and functionality of computer systems is the computer data that is stored on various storage devices within, or accessible to, the systems. Computer data (or simply "data") is being used to refer generically to data manipulated by the computer systems and instructions (e.g. software) executed by the computer systems.
Computer data can be corrupted or otherwise lost in a variety of fashions. For example, user error is frequently a source of corruption/data loss. Computer systems are particularly sensitive to errors made by users having administrative privileges (often referred to as "administrators") because such users can change important computer system configuration, including operating system configuration, that the computer system relies on for operation. Other sources of data corruption/loss may include hardware or software failures in one or more computer systems; malicious operation such as viruses, worms, "hacker" intrusions, etc.; environmental events such as power failures, accident, natural disaster, intentionally-caused disaster, etc.
To protect against data corruption/loss, various data protection mechanisms have been employed. For example, data backup, replication, and snapshot mechanisms are often used (either at the filesystem level or the logical volume level) to make a copy of the data that corresponds to a given point in time. However, the data protection mechanisms are costly, both in terms of physical resources consumed and the elapsed time to implement the copying. A given copy becomes out of date almost immediately (because original data continues being changed by the computer system). Due to the cost and time constraints, immediately making another copy using the above mechanisms is not feasible.
The VERITAS Volume Manager™ (VxVM) available from VERITAS Software Corporation (Mountain View, Calif.) implements a flexible snapshotting feature called FlashSnap. If a mirrored volume is created (that is, a volume that spans at least two physical storage devices and a copy of each datum in the volume is stored on each of the physical storage devices), a physical storage device may be "broken off" (disconnected from the volume) to permit a backup copy to be made (e.g. a snapshot). The break off can also happen involuntarily due to a software or hardware failure that makes said storage device inaccessible for a period of time. While the physical storage device is broken off, FlashSnap keeps a scoreboard of write operations to the mirrored volume at a selectable level of granularity (some multiple of the block size). Granularities may be, e.g., 64 kilobytes or 1 Megabyte. After the physical storage device is reattached, the write operations are applied to the physical storage device to sync its state to the state of the volume.