A jack assembly includes a jack element, an elastic element, and at least one latching portion. The jack element defines a jack opening configured for receiving an electronic element therein. The elastic element is mounted in a side of the jack element. The at least one latching portion protrudes on the elastic element and extends towards the jack opening. The at least one latching portion detachably latches the electronic element to the jack opening so as to secure the electronic element within the jack opening.

Portable electronic device, such as a mobile phone or a personal digital assistant (PDA), commonly has a jack for receiving an electronic element, for example, an earphone plug. When the electronic element is used, an unexpected pull on a line of the electronic element may pull the electronic element out of the jack.

Jack assembly and portable electronic device with same


Purified DNA encoding .alpha.(1,3)fucosyltransferase and the recombinant proteins expressed from such DNA are disclosed. The recombinant fucosyltransferase polypeptides are used to fucosylate proteins to produce therapeutics useful for the treatment of disease, e.g., an adverse immune reaction such as septiciemia or septic shock.

This invention relates to recombinant fucosyltransferases, DNA, and uses thereof.
The structurally related endothelial cell receptors E-selectin (Bevilacqua et al., Proc. Natl. Acad. Sci. USA 84:9238, 1987; Bevilacqua et al., Science 243:1160, 1989) and P-selectin (Hsu-Lin et al., J. Biol. Chem. 259:9121, 1984; Stenberg et al., J. Cell Biol. 101:880, 1985; Johnston et al., Blood 69:1401, 1987) mediate myeloid cell attachment to the vascular wall following activation of the endothelial cell by inflammatory cytokines (in the case of E-selectin; see, e.g., Bevilacqua et al. (1987), supra) or thrombin (in the case of P-selectin; see, e.g., Geng et al., Nature 343:757, 1990). Expressed both by Weibel-Palade bodies of endothelium (McEver et al., J. Clin. Invest. 84:920, 1989; Bonfanti et al., Blood 73:1109,.1989) and platelet alpha granules (Hsu-Lin et al., supra; Stenberg et al., supra), P-selectin also mediates monocyte and neutrophil binding to activated platelets (Larsen et al., Cell 59:305, 1989; Hamburger et al., Blood 75:550, 1990). The leading candidate ligands for the two receptors are the sialyl-Le.sup.x structure for E-selectin (Lowe et al., Cell 63:475, 1990; Phillips et al., Science 250:1130, 1990); Walz et al., Science 250:1132, 1990) and the same glycan in the context of a specific mucin, PSGL-1, (P-selectin glycoprotein ligand 1) for P-selectin (Sako et al., Cell 75:1179, 1993).
Genetic and biochemical data have demonstrated the existence of at least four distinct types of fucosyltransferases capable of forming the .alpha.(1,4) linkage: the Lewis enzyme (Fuc-TIII), which can transfer fucose either .alpha.(1,3) or .alpha.(1,4) to Gal.beta.4GlcNAc or Gal.beta.3GlcNAc respectively (Kukowska-Latallo et al., Genes Dev. 4:1288, 1990); at least one enzyme, Fuc-TIV, solely forming .alpha.(1,3) linkages, which cannot utilize sialylated substrates (Goelz et al., Cell 63:1349, 1989; Lowe et al., J. Biol. Chem. 266:17467, 1991); at least two enzymes, Fuc-TV (Weston et al., J. Biol. Chem. 267:4152, 1992a) and Fuc-TVI (Weston et al., J. Biol. Chem. 267:24575, 1992b) solely forming .alpha.(1,3) linkages, which can fucosylate either sialylated or nonsialylated precursors, and a recently described enzyme, Fuc-TVII, (Sasaki et al., J. Biol. Chem. 269:14730, 1994); Natsuka et al., J. Biol. Chem. 269:16789, 1994) which can fucosylate only sialylated precursors.

Fucosyltransferase genes and uses thereof


A console for an enterprise suite is disclosed. The enterprise suite addresses the increasingly complex problem of keeping critical systems updated, compatible, and free of security holes. It uses Fixlet® technology to identify vulnerable computers on the network and then allows authorized personnel to correct problems across any subset of the network with a few simple mouse-clicks. The enterprise suite helps keep the networked computers updated and properly patched, all from a central console which, along with supporting architectural enhancements, is the subject matter of this document. The invention allows rolling out a security patch in minutes instead of months, thus allowing an administrator to stay ahead of potential hacker attacks. The invention also makes it possible to track the progress of each computer as updates are applied, thus making it simple to gauge the level of compliance across the entire enterprise.

1. Technical Field
The invention relates to the network management technology. More particularly, the invention relates to an enterprise console for management of large-scale the networks of computational devices.
2. Description of the Prior Art
Information technology (IT) administrators in enterprises everywhere face a daunting task of managing the software and hardware on tens, hundreds, or thousands of machines in their domains. With so many incompatibilities, patches, and policy advisories announced daily, the task is much more than just acquisition and installation. Even simply keeping aware of all potentially problematic situations on hardware and software products used in an enterprise requires more than a full-time job. Dealing with those situations in response to user complaints adds still further taxing demands. Thus, it is required that IT managers must anticipate the situations which may soon arise in a specific enterprise and make plans to deal with those before they cause major problems. This creates an urgent need of a technique which enables the IT managers to understand the configuration of the hardware and software in a given intranet, to keep track of the policy advisories, updates, incompatibilities and patches relevant to the specific enterprise, and to match those policy advisories, updates, and patches with the specific equipment in the enterprise.
Donoho et al disclose in U.S. Pat. No. 6,256,664 a technique which enables a collection of computers and associated communications infrastructure to offer a new communications process. This process allows information providers to broadcast information to a population of information consumers. The information may be targeted to those consumers who have a precisely formulated need for the information. This targeting may be based on information which is inaccessible to other communications protocols because, for example, under other protocols the targeting requires each potential recipient to reveal sensitive information, or under other protocols the targeting requires each potential recipient to reveal information obtainable after extensive calculations using data available only upon intimate knowledge of the consumer computer, its contents, and local environment.
This process enables efficient solutions to a variety of problems in modern life, including the automated technical support of modern computers. In the technical support application, the disclosed invention allows a provider to reach precisely those specific computers in a large consumer population which exhibit a specific combination of hardware, software, system settings, data, and local environment, and to offer the users of those computers appropriate remedies to correct problems known to affect computers in such situations.
FIG. 1 is a schematic block diagram illustrating a communications system for computed relevant messaging according to the prior art. A user directs an advice reader running on his computer 101 to subscribe to three advice provider sites 103-105. The corresponding advice is brought into his computer in the form of digital documents, where the advice reader inspects the advisories for relevance. These digital documents are called advisories. The transfer from Internet 102 to computer is entirely one-way. No information about the user's machine goes back to the advice provider. An advice typically comprises three parts: (1) a relevance clause written in relevance language which is evaluated by the advice reader to determine the relevance of the advice; (2) a message body for providing explanatory material explaining to an advice consumer as to what condition is relevant, why the advice consumer is concerned, and what action is recommended; and (3) an action button for providing the advice consumer with the ability to invoke an automatic execution of a recommended action.
Whereas in the consumer setting it is acceptable for the computer user to be in control of the process, learning which problems exist and applying the fixes, in the enterprise setting it is often the case that end user administration of computers is frowned upon. Instead, computers are often managed centrally, and a system administrator is in charge of keeping configurations workable and avoiding enterprise-wide problems.
What is desired is a technique that provides centralized advice management in a large-scale the network of computers.
What is further desired is that such technique provides a management interface that can display relevant advisories of all computers in the network and deploy suggested actions to all relevant computers.
What is still further desired is that such management interface allows a system administrator to manage subscription of advice provider sites, monitor status of deployed actions and monitor status of computers in the network.
What is still further desired is that such technique can automatically apply the required management tasks to fix problems on susceptible machines before they occur.
Commonly assigned PCT application no. PCT/US02/36644, which application is incorporated herein in its entirety by this reference thereto, discloses a system and method for centralized advice management of large-scale the networks, wherein a number of distributed clients run on registered computers, gathering advisories and report relevance to a central server. A system administrator may view the relevant messages through a management interface and deploy suggested actions to distributed clients where the actions are executed to apply the solutions of the advisories.
In a preferred embodiment, a centralized advice management system includes a plurality of distributed clients, a central server, a central database, and a management interface. The distributed clients gather advisories from a plurality of advice provider sites and report relevance of advisories to the central server. A system administrator may view the details of relevant advisories and deploy the suggested actions to distributed clients of relevant computers, where the actions are executed to apply solutions provided by the advisories.
In another equally preferred embodiment, a centralized advice management system includes a plurality of distributed clients, a mirror server, a central server, a central database, and a management interface.
In another equally preferred embodiment, a centralized advice management system having a distributed client is provided, in which the distributed client comprises various components performing functions such as gathering advisories, authenticating advisories, evaluating relevance of advisories, registering a computer to a central server, reporting relevance to the central server, listening messages from the central server, gathering deployed actions from the central server, and executing deployed actions.
In another equally preferred embodiment, a method for providing centralized advice management for large-scale computer the networks is disclosed that comprises the steps of:                The distributed clients on the computers register to a central server;        A system administrator subscribes registered computers to advice provider sites;        The distributed clients gather advisories from subscribed advice provider sites;        The distributed clients report relevance to the central server;        The system administrator views relevant advisories using a management interface;        The system administrator deploys actions suggested by the advisories to the distributed clients; and        The distributed clients execute the deployed actions to apply the solutions of the advisories.
The method may further comprise a step to manage subscription of advice provider sites to the distributed clients. It may further comprise a step to monitor the status of deployed actions. Alternatively, it may further comprise a step to monitor the status of registered computers.
It would be advantageous to provide an enterprise console by which such system is used to identify vulnerable computers on the network, and that then allows authorized personnel to correct problems across any subset of the network with a few simple mouse-clicks.


An earth boring drill bit design for alleviating balling varies the junk slot depth in junk slots subject to balling from the other junk slots. Using variable depth bit bodies enhances the hydraulic characteristics of the bit as well as assists in the placement of the nozzles for machining purposes. This flexibility optimizes the area changes along the ducts required by the bit's operation.

1. Technical Field
The present invention relates in general to drill bit junk slots and, in particular, to an improved system, method, and apparatus for alleviating balling with variable junk slot depths in PDC drill bits.
2. Description of the Related Art
Polycrystalline diamond compact (PDC) drill bits have a common bit body and a plurality of fixed blades. Each pair of adjacent blades is separated by an elongated gap that is commonly referred to as a junk slot. Traditionally, PDC bits use the same junk slot depth for all junk slots. This design practice was acceptable when drill bits were created on a drafting table or with a two-dimensional computer aided (CAD) design system. However, with current three-dimensional CAD and computer aided manufacturing (CAM) systems, and numerically controlled machine tools the design of the bit body can be very flexible.
Drill bit "balling" occurs when the cuttings generated by a drill bit clog the junk slots such that removal of additional formation is impeded. Balling adversely affects the overall performance of drill bits and is generally recognized to be responsible for a significant reduction in the rate of penetration (ROP) of drill bits. Three factors that contribute to balling include: hydraulics (e.g., flow patterns, mud properties, etc.), operations (e.g., weight on bit, bit rotational speed, formation, etc.), and mechanical factors (e.g., a bit's physical design, cutter selection, etc.). Eliminating or controlling these factors directly affects the balling characteristics of any specific PDC bit.
Historically, the analysis of PDC drill bits with regard to balling has been focused on the operational parameters drilling mud rheology, flow rate and HSI. Although these two parameters have been shown to affect maximum penetration rates, other controllable variables have been identified that also contribute to bit balling. In addition, current models developed to predict ROP based on flow rate and/or HSI are not accurate, and no known model can establish the theoretical ROP limit for a given PDC drill bit. Thus, an improved drill bit design for reducing or eliminating balling would be desirable.

System, method, and apparatus for variable junk slot depth in drill bit body to alleviate balling


A composition for removing mildew is provided in composition comprising an aqueous solution of, by weight, about 2.75-4% sodium hypochlorite, about 0.5-1% sodium bicarbonate and about 0.5-5% d-limonene. The composition is particularly effective in removing mildew, mold and algae from variety of household surfaces, such as wood, metal, ceramic and plastic without damaging the surfaces. The composition is applied to the surface, usually by spraying, and allowed to react with the mildew. After a few seconds, the mildew is easily removed by rinsing with water. Furthermore, this particular combination has additional advantages in that it can also act simultaneously as a de-greaser, while giving off a pleasant citrus-like aroma.

This invention relates to a composition which is effective in removing microorganisms from surfaces. More particularly, this invention relates to a composition comprising an aqueous solution of sodium hypochlorite, sodium bicarbonate and d-limonene which is effective in removing mildew, mold and algae from various types of surfaces without harming the surfaces. The term mildew will be used hereinafter to refer generally to undesirable microorganisms which grow on surfaces, including mold and algae.
Numerous compositions containing hypochlorite and bicarbonate are known for treating a surface so as to prevent or remove unwanted biological material.
U.S. Pat. No. 4,664,836 to Taylor, Jr. et al. discloses a crystallized drain cleaner which contains 40-90% of a coated alkali metal hydroxide, 5-20% of a mixture containing a peroxide generator and a hypochlorite generator, 5-20% of a blend of 60% sodium bicarbonate and 40% citric acid. The dry product is added to water before use.
U.S. Pat. No. 4,889,654 to Mason et al. discloses an aqueous foam disinfectant which generates chlorine dioxide. An aqueous solution containing a foam generating agent and a metal chlorite (1-20%) is reacted with an acid solution which may contain sodium bicarbonate (1-50%), and a solution which may contain sodium hypochlorite (1-40%). The resulting solution is then diluted in water.
U.S. Pat. No. 4,507,424 to Webster discloses a composition for restoring grout having sodium carbonate and/or sodium bicarbonate (5-35%), sodium hypochlorite (1-15%), and a de-greasing surfactant (0.5-10%), as well as a resin, thickener, pigment and zinc oxide. The preferred composition is equal parts of carbonate, bicarbonate and hypochlorite, i.e. total of carbonate and bicarbonate at twice the amount of hypochlorite.
The above compositions all involve a long list of additional ingredients, resulting in a costly, complex, and possibly hazardous product which may not be suitable for use on a variety of surfaces found within and on a household.
It is therefore an object of the present invention to provide a composition for removing mildew which is suitable for household use.
It is a further object of the present invention to provide a composition which is characterized by economy and simplicity of manufacture and ease of use.
It is a still further object of the present invention to provide a composition which works immediately on contact to remove mildew from a variety of surfaces without damaging the surfaces, while also giving off a pleasant odor.

Composition for removing mildew containing hypochlorite, bicarbonate and d-limonene


The invention relates to a method and apparatus for of controlling the flow of a fluid. The fluid comprises a liquid phase and a dissolved gas phase. The fluid passes through a valve, the valve comprising a fluid inlet and a movable body located in a flow path through the valve, the movable body being arranged to move freely relative to the opening of the inlet to vary the flow-through area through which the fluid flows by means of the Bernoulli effect. The dimensions of the valve are such that flow of the fluid past the movable body causes a drop in pressure to below the bubble point of the gas phase in the liquid phase, thereby increasing flow of the fluid through the valve.

Devices for recovering of oil and gas from long, horizontal and vertical wells are known from U.S. Pat. Nos. 4,821,801, 4,858,691, 4,577,691 and GB patent publication No. 2169018. These known devices comprise a perforated drainage pipe with, for example, a filter for control of sand around the pipe. A considerable disadvantage with the known devices for oil/and or gas production in highly permeable geological formations is that the pressure in the drainage pipe increases exponentially in the upstream direction as a result of the flow friction in the pipe. Because the differential pressure between the reservoir and the drainage pipe will decrease upstream as a result, the quantity of oil and/or gas flowing from the reservoir into the drainage pipe will decrease correspondingly. The total oil and/or gas produced by this means will therefore be low. With thin oil zones and highly permeable geological formations, there is also a high risk of coning, i.e. flow of unwanted water or gas into the drainage pipe downstream, where the velocity of the oil flow from the reservoir to the pipe is the greatest.
From World Oil, vol. 212, N. 11 (11/91), pages 73-80, it is known to divide a drainage pipe into sections with one or more inflow restriction devices such as sliding sleeves or throttling devices. However, this reference mainly deals with the use of inflow control to limit the inflow rate for up hole zones and thereby avoid or reduce coning of water and or gas.
WO-A-9208875 describes a horizontal production pipe comprising a plurality of production sections connected by mixing chambers having a larger internal diameter than the production sections. The production sections comprise an external slotted liner which can be considered as performing a filtering action. However, the sequence of sections of different diameter creates flow turbulence and prevents the running of work-over tools operated along the outer surface of the production pipe.
When extracting oil and or gas from geological production formations, fluids of different qualities, i.e. oil, gas, water (and sand) is produced in different amounts and mixtures depending on the property or quality of the formation. None of the above-mentioned known devices are able to distinguish between and control the inflow of oil, gas or water on the basis of their relative composition and/or quality.
Devices as disclosed in WO2009/088292 and WO 2008/004875 are robust, can withstand large forces and high temperatures, can prevent draw downs (differential pressure), need no energy supply, can withstand sand production, yet are reliable, simple and very cheap. However, several improvements might nevertheless be made to increase the performance and longevity of the above device in which many of the different embodiments of WO2009/088292 and WO 2008/004875 describe a disc or plate as a movable body of the valve.
One potential problem with a disc or plate as the movable body is erosion on the movable body. This is due to a very large fluid velocity between an inner seat and the movable body of the valve. The fluid is subjected to abrupt changes in its flow direction at this location. As there will always be particles in the fluid flow, even if sand screens are installed, such particles will cause erosion. The erosion problem exists both with and without the use of a stagnation chamber in the valve.


Apparatus and methods for simultaneously cone cutting of crown portions and pavilions of gemstones are provided by the present invention. Each of the gemstones to be simultaneously cut are individually mounted in a motor rotating collet which is mounted on a base plate. One of the base plates is provided with additional motor-driven apparatus to move the plate at an angle of approximately 45.degree. to the axial center line of the gemstone. The second gemstone is rotated by a motor attached to the collet by a support plate. The support plate moves in a direction toward the first gemstone at an angle approximately 45.degree. to the axial center line of the second gemstone and, such that, it is perpendicular to the back and forth motion provided by the motor apparatus of the first gemstone. In this manner, each of the gemstones are simultaneously coned shaped at first its crown portion and then at its pavilion portion or visa versa.

1. Field of the Invention
This invention pertains in general to the field of gemstone cutting and in particular to an apparatus and method for cone shaping the crown and pavilion portion of gemstones, especially diamonds, prior to facet polishing for use in jewelry.
2. Description of the Prior Art
Gemstones are minerals or petrified substances, such as diamonds or turquoise, that can be cut and polished for placement in jewelry. The most famous and precious gemstone is the diamond, which is a colorless mineral composed entirely of carbon crystallized in the isometric system as octahedrons, dodecahedrons, and cubes. Although this invention encompasses gemstones in general, for purposes of discussion hereinafter, reference is made primarily to the diamond as the diamond is the hardest substance and often most valued by modern society. The diamond epitomizes the cost saving inventive method of this invention, because the transition from a rough stone to brilliant cut requires time consuming, costly, highly skilled laborers. A second factor is the costly wear and maintenance of expensive faceting equipment and diamond impregnated grinding wheels. The reason why diamond cutting is an extremely laborious task and expensive process compared to other gemstones is that other than the diamond being the hardest substance, it also has grain and knots similar to wood with regard to the grain or knots, so must the diamond cutter orient the diamond before it comes in contact with the grinding wheel, and if he does encounter a twisted grain or knot ( which is almost always invisible, even to the trained eye), he can occasionally take days to grind one facet (face).
The majority of rough carbon stones used to produce brilliant cut diamonds have an irregular octahedron configuration which approximates the shape of an irregular four-sided pyramid joined at its base to another irregular four-sided pyramid. The rough stones are individually studied by the skilled laborer to determine whether one or two finished gem quality diamonds (for jewelry) are to be made from the stone. The main determination of cutting a rough stone depends upon whether the cut will result in maximum weight retention. Generally, the conversion of a rough stone diamond to a finished diamond results in the loss of approximately fifty percent of the original stone weight. Thus, two major disadvantages to the prior art is the costly need for skilled laborers to spend an excessive amount of time grinding away the unwanted bulk together with the fact that approximately 90% of the weight loss during conversion is not salvageable.
The first step in diamond cutting consists of sawing the rough stone essentially parallel to the major axis of the octahedron by a very thin phosphorous bronze disk blade having a thickness of approximately two to three one-thousandths of an inch. The edge of a blade is coated with a paste of olive oil and diamond powder.
If two diamonds are to be made from a single rough stone, each of the sawed halves are thereafter individually processed by first girdling,(brutting) or creating a cylindrical surface around the outer circumference of the stone. The girdling (brutting) is accomplished by cementing one sawed diamond half to a dop and then fixing the dop within a lathe type machine such that it rotates about an axial center line of the girdled diameter. During rotation, a technician hand machines the girdle around the stone by using an industrial diamond attached to the head of a relatively long stick. Another method to girdle (brutt) the rough diamond and other gemstones is to move a rotating dop having the rough stone centered therein into contact with a rotating grinding wheel.
Once the rough diamond has been girdled, the main reference configuration has been prepared from which all other operations comprising cutting and polishing of the stone are referenced with regard thereto. Namely, the crown (top) and pavilion (bottom) portions of the diamonds are cut and polished into a conical shape. It should be noted that the shaping/coning of the top/crown is shaped at 34.degree. and the bottom pavilion at 41 for diamonds. These angles are the same used in the faceting process. These angles are unique to diamonds providing the completed diamond with optimum brilliance. These angles will vary from one gemstone material to another. Each facet on the finished diamond is individually cut and polished by hand. Facets are placed on the crown and pavilion by use of a large rotating cast iron wheel impregnated with diamond powder. The diamond is held in the dop attached to a tang. The dop is held in a fixed position and pressed against the wheel as it rotates. A new position is set for each facet to be grounded. The skilled technician proceeds to grind and polish each of the facets onto the surface of the stone to a predetermined depth. It should be noted that the diamond can only be ground in accordance with its crystalline structure. Further, throughout the above mentioned steps, diamond or diamond powder is required. Course Diamond powder is used for the rough cutting of the facets, and fine diamond powder for the polishing of the facets.
U.S. Pat. No. 3,202,147 issued to Roos discloses a method for making the girdle using a first axially aligned motor and dop having a diamond attached thereto angled at 90.degree. to another axially aligned motor and dop having a second diamond attached thereto. Roos allows for bringing the rotating rough diamonds into contact with each other such that the axis of rotation of each crosses each other and whereby each of the rotating rough diamond chips the other and forms a hollow girdle on each. By moving the rotating dops backward and forward in an axial direction, girdles having purely straight profiles are obtained. When the operator sees that one stone has the correct sized girdle, it is replaced by a new rough stone and the process is continued until the other stone has assumed the correct size and shape and so on. Roos fails to disclose or teach a method to cone the crown or the pavilion portions of the stone.
Accordingly, the instant invention overcomes the above mentioned shortcoming by providing a method and apparatus which reduces the overall cutting time from rough stone to a facet-ready stone and teaches reducing the need for a skilled technician or diamond cutter by precisely shaping the crown and pavilion portions of the rough stone into a preform shape ready for placement of facets. The preformed diamond is now within ten percent of its final polished weight. Time saving is further realized with the invention through a process and a machine that permits diamond coning of at least two diamonds simultaneously without the need of grinding wheels thus permitting capture of nearly 100% of produced diamond dust.
The difficulty overcome by my invention is that in prior art the removal of unwanted bulk from gemstones was accomplished using costly highly skilled craftsman with expensive high maintenance machines whereas my invention efficiently and accurately removes the unwanted bulk and retains it using a relatively low cost machine with low cost maintenance and very low skilled workers and at least twice the speed of removal by prior art.
Precision cone making as described herein by any means is a novel unique process that has not been done before in precious gemstone cutting. The invention may also be used to shape synthetic and industrial diamonds for industrial gem purposes.

Apparatus and method for cone shaping the crown and pavilion of gemstones


A sheet bundle conveying device includes a tray device on which sheets are placed and held in a bundle, a sheet bundle conveying path along which a sheet bundle from the tray device is guided to a predetermined processing position, a grip transferring device located on the sheet bundle conveying path for gripping and transferring the sheet bundle from the tray device to a processing position, and a grip controlling device for controlling the grip transferring device. When an apparatus error occurs, the grip transferring device moves the conveyed sheet bundle backward to the collection stage. A grip on the sheet bundle is released on the collection stage after the sheet bundle is returned.

The present invention relates to a sheet bundle conveying apparatus wherein grip means are used to grip and convey bundled sheets to a predetermined position in a bookbinding apparatus that aligns sequentially supplied print sheets into a bundle and then binding them to a cover sheet with a paste or any other adhesive.
Sheet bundle conveying devices that collect and, for example, align sheets into a bundle and transfer the sheet bundle to a processing position are widely used for various bookbinding apparatus and postprocess apparatus for image forming apparatus. These sheet bundle conveying devices use a grip conveying mechanism that uses gripper means to grip and convey the sheet bundle to the processing position.
A conventional book binding apparatus comprising a grip conveying mechanism is disclosed in Japanese Patent Laid-Open No. 2004-209869. This document proposes an apparatus that stacks and aligns sheets printed by an image forming apparatus, such as a printer or a printing machine, on a stacking tray in order of pages, conveys the bundled sheets to a predetermined paste applying position, and places the sheet bundle with a paste applied thereto, in the cover sheet. The mechanism conveying the sheet bundle from the stacking tray to the predetermined paste applying position uses a pair of grippers, comprising an upper gripper and a lower gripper, to clamp the sheet bundle. The mechanism then moves the grippers along a path to convey the sheet bundle. Moreover, the apparatus disclosed in the document collects bundled sheets on the stacking tray in a horizontal posture, uses the grippers to change the posture of sheet bundle to a vertical one, applies a paste to the sheet bundle in the vertical posture, and conveys a cover sheet to a downstream position where the cover sheet is bound to the sheet bundle.
Consequently, the sheets from the image forming apparatus are collected in a horizontal posture and then moved along the path while being supported in the vertical posture. During this process, the sheets are subjected to sequential bookbinding steps. Thus, in the apparatus disclosed in Japanese Patent Laid-Open No. 2004-206369, when an apparatus error, for example, jamming or power interruption, occurs during the bookbinding process, a sheet bundle that has not been completely processed is left in the apparatus. Then, when the apparatus is restarted, the remaining sheets are removed from the apparatus and a normal bookbinding process is then continued.
As described above, when the grip conveying mechanism conveys the sheet bundle from the stacking tray means to the downstream processing position, if the apparatus is stopped for any reason with the sheet bundle gripped by the grip conveying mechanism, the conventional technique requires the operator to perform a recovery operation, such as removing the sheet bundle gripped by the grip conveying mechanism in order to return the apparatus to its initial state and then restarting the apparatus. However, to remove the bundled sheets from the grip conveying mechanism, the grip force of the grip conveying mechanism must be released. In this case, loosened sheets may fall and scatter in the apparatus. In particular, with the path configuration in which the sheet bundle is conveyed in the vertical posture, if the timing for releasing the grip force of the grip conveying mechanism does not coincide with the timing when the operator receives the sheet bundle, the sheets may fall and scatter. Removal of the fallen sheets is dangerous and cumbersome.
In view of the above problems, an object of the present invention is to provide a method and device for transferring a sheet bundle which, if a bookbinding apparatus is irregularly stopped during a bookbinding process, allows a sheet bundle remaining in the device to be easily removed, preventing the sheets from scattering.
Another object of the present invention is to provide a bookbinding apparatus wherein, when sheets from an image forming apparatus are subjected to an automatic bookbinding process and if the bookbinding apparatus is irregularly stopped, a sheet bundle remaining in the bookbinding apparatus is automatically conveyed to a predetermined takeout position to enable an effective operation without the need to remove the remaining sheets.
The other objects and features of the present invention will be apparent from the description below of embodiments taken in conjunction with the accompanying drawings.

Sheet bundle conveying apparatus, and bookbinding apparatus


An apparatus and method of supporting lead fingers during a wire bonding process and of preventing the bonding apparatus and clamping assembly from applying force against the die are available. The present invention includes the use of a movable arm with a portion that is positionable under a portion of the lead fingers of a lead frame during the wire bonding process to provide increased stability of the lead fingers and prevent the bonding apparatus and clamping assembly from applying force against the die. The present invention also provides for the transfer of heat from the heat block directly to the lead fingers during the wire bonding process. The present invention includes the use of a clamp for stabilizing lead fingers during the wire bonding process.

1. Field of the Invention
The present invention is related to forming wire bonds between the contact pads on semiconductor devices and individual lead frame fingers of a lead frame.
More specifically, the present invention is related to the apparatus and method of supporting the lead fingers of a lead frame during a wire bonding process using a support arm with a lead support portion that is positionable between the lead fingers and the die prior to the bonding process to help substantially stabilize the lead fingers during the bonding process.
2. State of the Art
Well known types of semiconductor devices are connected to lead frames and subsequently encapsulated in plastic for use in a wide variety of applications. Typically, the lead frame is formed from a single continuous sheet of metal by metal stamping operations. In a conventional lead frame, the lead frame includes an outer supporting frame, a central semiconductor chip supporting pad and a plurality of lead fingers, each lead finger having, in turn, a bonding portion thereof near the central chip supporting pad. Ultimately, the outer supporting frame of the lead frame is removed after the wire bonds between the contact pads of the semiconductor chip device and the lead fingers are made and the semiconductor device and a portion of the lead frame have been encapsulated.
In the assembly of semiconductor devices utilizing such conventional lead frames, a semiconductor die is secured to the central supporting pad (such as by a solder or epoxy die-attach, although a double-sided adhesive tape-type attach has also been suggested in the art) and then the entire lead frame, with the semiconductor die thereon, is placed into a wire bonding apparatus including a clamp assembly for holding the lead frame and die assembly, and clamping the lead fingers for bonding.
In contrast to a conventional lead frame, U.S. Pat. No. 4,862,245 issued Aug. 29, 1989 to Pashby et al. illustrates a so-called "leads over chip" arrangement ("LOC") on the semiconductor die. A plurality of lead fingers of the lead frame extend over the active surface of a semiconductor die toward a line of bond pads thereon wherein bond wires make the electrical connection between the lead fingers and the bond pads. An alpha barrier such as a polyamide tape (for example, Kapton.TM. tape) is adhered between the semiconductor die and the lead fingers. This configuration, which eliminates the use of the previously-referenced central die attach pad, may assist in limiting the ingress of corrosive environment contaminants after encapsulation of the semiconductor device, achieve a larger portion of the lead finger path length encapsulated in the packaging material, and reduce electrical resistance caused by the length of the bond wires (i.e. the longer the bond wire, the higher the resistance) and potential wire sweep problems in the encapsulation of the semiconductor device aggravated by long wire loops.
In a standard wire bonding process, the bond wires are attached, one at a time, from each bond pad on the semiconductor device and to a corresponding lead finger. The bond wires are generally attached through one of three industry-standard wire bonding techniques: ultrasonic bonding--using a combination of pressure and ultrasonic vibration bursts to form a metallurgical cold weld; thermocompression bonding--using a combination of pressure and elevated temperature to form a weld; and thermosonic bonding--using a combination of pressure, elevated temperature, and ultrasonic vibration bursts.
To form a good bond during the wire bonding processing, it is preferable to perform the bonding at an elevated and somewhat stable temperature. Therefore, as noted above, the lead frame assembly including the attached semiconductor die is generally placed on a heater block. The semiconductor die is then clamped (via the lead frame) to the heater block by a clamping assembly. With a conventional lead frame, the lead fingers are clamped directly against the underlying heater block. Whereas, in an LOC lead frame, the lead fingers are biased between the clamp and the active surface of the semiconductor die heater block. Thus, in an LOC lead frame arrangement, the clamping assembly and bonding apparatus apply pressure against the die thereby causing possible damage. In addition, heating of the lead fingers in an LOC lead frame for wire bonding must be done through heating the die as apposed to directly heating the lead fingers by the heater block in a conventional lead frame.
Therefore, in an LOC lead frame configuration it would be advantageous to develop an apparatus to prevent the clamping assembly and bonding apparatus from applying force against the die. In addition, it would be advantageous to develop an apparatus for transferring heat directly from the heat block to the lead fingers.
In an LOC structure, the Kapton.TM. tape comprising the alpha barrier or dielectric between the semiconductor and the lead fingers becomes soft at the elevated temperature. The softening of the tapes allows the lead fingers and/or semiconductor die to move in response to ultrasonic energy or pressure (force) exerted by the wire bonding head (capillary). As a result, the mechanical integrity of the wire bond to the lead fingers is diminished. Furthermore, a "bouncing" motion is imparted to the lead fingers by the wire bonding head movement, which motion may be exacerbated by the heat softened tape. This bouncing motion can also result in poor wire bonds which subsequently fail.
Thus, die fabricators are somewhat compelled to select the die attach compound (or other means) and alpha barrier tape based on the thermal stability of the materials rather than on the basis of the most effective material for a given application.
Therefore, it would be advantageous to develop an apparatus that would replace the alpha barrier tape while stabilizing the semiconductor die and the lead fingers during the wire bonding process.
Typical apparatus and methods for clamping the lead frame during the wire bonding process or for clamping and advancing the lead frame are illustrated in U.S. Pat. Nos. 4,765,531, 5,082,165, 5,238,174, 5,264,002, 5,307,978, 5,322,207, and 5,372,972. However, such apparatus and methods do not address the problem of supporting the lead fingers during the wire bonding process or preventing the application of force on the die.
Such prior art apparatus and methods have been directed at advancing and orienting the lead frame but have not attempted to solve the problems of forming reliable wire bonds between the contact pads of semiconductor devices and lead fingers of lead frames.
There have been other attempts to overcome the problem of the bouncing motion imparted to the lead fingers by the wire bonding head movement. For example, for bonding LOC structures, rigid clamping plates having bond site windows therein have been reconfigured so that the bond site window is reduced in size and the downwardly-extending lip or periphery contacts the lead fingers extending over the die and clamps the lead fingers directly thereto. However, the rigid clamp has been found to be too rigid and unyielding for use with an LOC configuration, and may possibly damage the die. Moreover, the use of a rigid clamp adds to the force exerted against the die and does nothing to prevent the application of force by the bonding apparatus.
The present invention is directed to an improved wire bonding apparatus and method for forming such wire bonds.

Apparatus and method of clamping semiconductor devices using sliding finger supports


By removing a portion of a halo region or by avoiding the formation of the halo region within the extension region, which may be subsequently formed on the basis of a re-grown semiconductor material, the threshold roll off behavior may be significantly improved, wherein an enhanced current drive capability may simultaneously be achieved.

1. Field of the Invention
Generally, the present invention relates to the formation of integrated circuits, and, more particularly, to the formation of semiconductor regions including enhanced dopant profiles formed by means of halo regions.
2. Description of the Related Art
The fabrication of integrated circuits requires the formation of a large number of circuit elements on a given chip area according to a specified circuit layout. For this purpose, substantially crystalline semiconductor regions with or without additional dopant materials are defined at specified substrate locations to act as "active" regions, that is, to act, at least temporarily, as conductive areas. Generally, a plurality of process technologies are currently practiced, wherein, for complex circuitry, such as microprocessors, storage chips and the like, MOS technology is currently one of the most promising approaches, due to the superior characteristics in view of operating speed and/or power consumption and/or cost efficiency. During the fabrication of complex integrated circuits using, for instance, MOS technology, millions of transistors, e.g., N-channel transistors and/or P-channel transistors, are formed on a substrate including a crystalline semiconductor layer. A transistor, irrespective of whether an N-channel transistor or a P-channel transistor or any other transistor architecture is considered, comprises so-called PN junctions that are formed by an interface of highly doped regions, such as drain and source regions, with a slightly doped or non-doped region, such as a channel region, disposed adjacent to the highly doped regions.
In the case of a field effect transistor, the conductivity of the channel region, i.e., the drive current capability of the conductive channel, is controlled by a gate electrode formed adjacent to the channel region and separated therefrom by a thin insulating layer. The conductivity of the channel region, upon formation of a conductive channel, due to the application of an appropriate control voltage to the gate electrode, depends on the dopant concentration, the mobility of the charge carriers, and, for a given extension of the channel region in the transistor width direction, on the distance between the source and drain regions, which is also referred to as channel length. Hence, in combination with the capability of rapidly creating a conductive channel below the insulating layer upon application of the control voltage to the gate electrode, the conductivity of the channel region substantially affects the performance of MOS transistors. Thus, as the speed of creating the channel, which depends on the conductivity of the gate electrode, and the channel resistivity substantially determine the transistor characteristics, the scaling of the channel length, and associated therewith the reduction of channel resistivity and the increase of gate resistivity, renders the channel length a dominant design criterion for accomplishing an increase in the operating speed of the integrated circuits.
The continuing shrinkage of the transistor dimensions, however, entails a plurality of issues associated therewith that have to be addressed so as to not unduly offset the advantages obtained by steadily decreasing the dimensions of transistors. One major problem in this respect is the development of enhanced photolithography and etch strategies to reliably and reproducibly create circuit elements of critical dimensions, such as the gate electrode of the transistors, for a new device generation. Moreover, highly sophisticated dopant profiles, in the vertical direction as well as in the lateral direction, are required in the drain and source regions to provide low sheet and contact resistivity in combination with a desired channel controllability.
However, the reduction of the gate length is associated with a reduced controllability of the respective channel, thereby requiring pronounced lateral dopant profiles and dopant gradients, at least in the vicinity of the PN junctions. Therefore, so-called halo regions are usually formed by ion implantation in order to introduce a dopant species whose conductivity type corresponds to the conductivity type of the remaining channel and semiconductor region so as to "reinforce" the resulting PN junction dopant gradient after the formation of respective extension and deep drain and source regions. In this way, the threshold voltage of the transistor, which represents the voltage at which a conductive channel forms in the channel region, significantly determines the controllability of the channel, wherein a significant variance of the threshold voltage may be observed for reduced gate lengths. Hence, by providing an appropriate halo implantation region, the controllability of the channel may be enhanced, thereby also reducing the variance of the threshold voltage, which is also referred to as threshold roll off, and also reducing significant variations of transistor performance with a variation in gate length. With the ongoing shrinkage of the gate length, however, an efficient compensation for threshold variance by a halo implantation may result in a significant degree of counter-doping of the respective extension regions, in particular when very shallow and thus highly doped halo implantations are required, which may more efficiently reduce the threshold variance compared to deeper halo implantations, which may be provided with a reduced dopant concentration yet provide a less efficient compensation mechanism. Consequently, the channel controllability may be enhanced by reducing the thickness of the gate insulation layer, which may however be restricted by increased static leakage currents and the physical limits of well-approved insulating materials, such as silicon dioxide.
With reference to FIGS. 1a-1c, the problems involved in the formation of conventional transistor devices will be described in more detail. FIG. 1a schematically illustrates in a cross-sectional view a first transistor element 100S, which may receive a shallow halo implantation, and a second transistor element 100D for receiving a moderately deep implantation. The first and second transistors 100S, 100D may comprise respective gate electrodes 104 that are formed above a channel region 103 provided in a semiconductor material 102, such as a silicon layer, which in turn is formed above a substrate 101. The gate electrode 104, which may have formed on sidewalls thereof a spacer element 107, is separated from the channel region 103 by a gate insulation layer 105. It may be assumed that the transistors 100S, 100D may have substantially the same configuration with respect to the components described so far. Moreover, the transistor 100S may be subjected to an ion implantation process 108S for forming in the semiconductor layer 102 respective halo regions 106S, which may be considered as shallow halo regions, which may be highly efficient in enhancing the controllability of the channel forming in the channel region 103 during operation of a device 100S. Thus, the implantation process 108S is performed with appropriate process parameters, such as implantation dose, energy and, as shown, tilt angle with respect to a direction substantially perpendicular to the layer 102, so as to obtain the implantation region 106S extending to a certain degree below the structure defined by the gate electrode 104 and the spacer 107, which acts as an implantation mask. It is to be noted that, however, a moderately high implantation dose and thus dopant concentration in the shallow region 106S is required in order to provide the efficient compensating mechanism for reducing short channel effects, such as reduced threshold roll off, to obtain enhanced channel controllability. On the other hand, the second transistor 100D is subjected to a halo implantation 108D, which is designed to provide a lower dopant concentration, thereby requiring a significantly greater depth so as to provide a moderately high compensation effect with respect to the threshold variance. It should be appreciated that a thickness of the gate insulation layer 105 may typically range from 1-3 nm and thus may not be significantly reduced on the basis of frequently used materials, such as silicon dioxide, silicon nitride and the like. The transistors 100S, 100D may be formed on the basis of well-established techniques, which include substantially the same processes for both transistors except for the halo implantations 108S, 108D.
FIG. 1b schematically shows the transistors 100S and 100D in a final manufacturing stage. Both transistors 100S, 100D may comprise an appropriate sidewall spacer structure 111, which may comprise a plurality of individual spacer elements and appropriate liner materials, depending on process and device requirements. Moreover, drain and source regions 110 connected to respective extension regions 109 may be formed within the semiconductor layer 102 adjacent to the channel region 103, wherein the extension regions 109 may form with the respective halo region 106S or 106D a PN junction, as is previously explained. Moreover, metal silicide regions 112 may be formed within the drain and source regions 110 and the gate electrode 104 in order to reduce the series resistance for connecting to the gate electrode 104 and the drain and source regions 110.
Typically, the transistors 100S, 100D may be formed by performing an appropriate implantation process for forming extension regions 109, possibly by providing an appropriate spacer element (not shown) or on the basis of the spacer 107, depending on the process and device requirements. Thereafter, the spacer structure 111 may be formed on the basis of well-approved techniques including the deposition of an appropriate material, such as silicon nitride, and a subsequent anisotropic etch process. Thereafter, a further implantation process may be performed in order to introduce dopant material for forming the deep drain and source regions 110. It should be noted that other implantation processes, as well as any intermediate anneal processes for activating respective dopant material, may also have been performed prior to the formation of the extension regions 109 and the drain and source regions 110 or may have been performed intermittently. After the completion of the respective implantation and anneal processes, thereby forming the PN junction between the extension region 109 and the halo regions 106S or 106D, the metal silicide regions 112 may be formed on the basis of any appropriate process technique, for instance involving the deposition of any appropriate refractory metal, such as cobalt, titanium, nickel, platinum or combinations thereof, with a subsequent heat treatment for forming a respective metal silicide.
FIG. 1c schematically illustrates the behavior of the transistors 100S, 100D with respect to a variation of threshold voltage with gate length, i.e., in FIGS. 1a and 1b the horizontal dimension of the gate electrodes 104, for otherwise identical configuration, wherein, as previously explained, a shallow halo implantation region, such as the region 106S, may provide a reduced variance of the threshold voltage for a decreasing gate length, as is indicated by the curve A in FIG. 1c. On the other hand, a moderately deep halo implantation region, such as the region 106D, may, for an otherwise identical transistor configuration, result in a significantly pronounced threshold roll off, thereby rendering this type of transistor less appropriate for sophisticated applications. Although the transistor 100S may be advantageous in view of its behavior with respect to the threshold roll off, the moderately high dopant concentration in the region 106S may, however, have a significant impact on the overall series resistance of the transistor 100S, thereby significantly reducing its current drive capability. That is, due to the moderately high dopant concentration in the halo implantation region 106S, a high degree of counter-doping is provided in the extension region 109, thereby reducing the conductivity thereof. Hence, a portion 109A between the metal silicide 112 and the channel region 103 may have an increased resistance compared to the respective region 109A of the transistor 100D, which has a significantly lower dopant concentration in the respective halo region 106D. Consequently, typical transistor configurations for advanced applications may represent a compromise between enhanced threshold roll off behavior with respect to drive current capability.
In view of the situation described above, there exists a need for an enhanced technique for forming transistor elements while avoiding one or more of the problems identified above or at least reducing the effects thereof.

Transistor device having an increased threshold stability without drive current degradation


A semiconductor device employing a PD-SOI substrate and a method of manufacturing the same are capable of minimizing a floating body effect. The semiconductor device employs a silicon layer over a buried insulating layer on a silicon wafer, isolating layers in the silicon layer in contact with the buried insulating layer, a body layer of a first conductivity type in the silicon layer between the isolating layers and having a trench, a gate insulating layer and a gate electrode in the trench of the body layer, a spacer on the sidewall of the gate electrode, LDD regions of a second conductivity type in the body layer on both sides of the gate electrode in contact with the buried insulating layer under the trench, and source and drain regions of the second conductivity type the body layer on both sides of the spacer in contact with the buried insulating layer.

(a) Field of the Invention
The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly to a semiconductor device employing partially depleted-silicon on insulator (PD-SOI) substrate and a method of manufacturing the same.
(b) Description of the Related Art
Generally, an SOI substrate employs a silicon layer formed over an insulating layer on a silicon wafer, to have a structure in which the insulating layer is buried within the silicon layers.
Therefore, in the case of manufacturing a metal oxide silicon (MOS) transistor in this SOI substrate, body layers of the MOS transistor are isolated by the buried insulating layer and an isolating layer, and as a result, the speed and the integration density of the MOS transistor are improved.
This SOI substrate is classified into a fully depleted type (FD) and a partially depleted type (PD) based on the thickness of the silicon layer.
First, a MOS transistor employing the FD-SOI substratewill be described with reference to a FIG. 1.
As shown in FIG. 1, isolating layers 11 are formed in a silicon layer 10c of a FD-SOI substrate 10 employing the silicon layer 10c that is formed relatively thinly over a buried insulating layer 10b on a silicon wafer 10a to be in vertical contact with the buried insulating layer 10b, and a body layer 12 of a P well is formed in the silicon layer 11c between the isolating layers 11. A gate insulating layer 13 and a gate electrode 14 are sequentially formed on the body layer 12. LDD (Lightly Doped Drain) regions 15 in which low concentration impurities, for example N− are ion-implanted, are formed within the body layer 12 of both sides of the gate electrode 14 to be in contact with the buried insulating layer 10b. A spacer 16 of an insulating material is formed on the side wall of the gate electrode 14. Source and drain regions 17 in which high concentration impurities, for example N+ are ion-implanted, are formed within the body layer 12 of both sides of the spacer 16 to be in contact with the buried insulating layer 10b.
Thus, in the MOS transistor employing the FD-SOI substrate, as the LDD regions 15 and the source and drain regions 17 are formed within the body layer 12 to be in contact with the buried insulating layer 10b by the thin silicon layer 10c, a depletion layer is fully formed in the body layer 12 when a back bias voltage is not applied to the body layer 12.
Next, a MOS transistor employing the PD-SOI substratewill be described with reference to a FIG. 2.
As shown in FIG. 2, isolating layers 21 are formed in a silicon layer 20c of a PD-SOI substrate 20 employing the silicon layer 20c that is formed relatively thickly over a buried insulating layer 20b to be in vertical contact with the buried insulating layer 20c, and a body layer 22 of a P well is formed in the silicon layer 20c between the isolating layers 21. A gate insulating layer 23 and a gate electrode 24 are sequentially formed on the body layer 22. LDD regions 25 in which low concentration impurities, for example N− impurities are ion-implanted, are formed within the body layer 22 of both sides of the gate electrode 24 to be separated from the buried insulating layer 20b. A spacer 26 of an insulating material is formed on the side wall of the gate electrode 24. Source and drain regions 27 in which high concentration impurities, for example N+ impurities are ion-implanted, are formed within the body layer 22 of both sides of the spacer 26 to be separated from the buried insulating layer 20b.
Thus, in the MOS transistor employing the PD-SOI substrate, as the LDD regions 25 and the source and drain regions 27 are formed within the body layer 22 to be separated from the buried insulating layer 20 by the thick silicon layer 20c, a depletion layer is partially formed in the body layer 22 when a back bias voltage is not applied to the body layer 22.
Therefore, a floating body region exists under a channel region, so that a floating body effect occurs.
This floating body effect accumulates holes generated by impact ionization of electrons around a drain region in the floating body region, to increase the potential of the body layer and to lower a potential barrier between the source region and the body layer, thereby decreasing a threshold voltage and increasing a drain current.
Furthermore, if the potential of the body layer will be increased above 0.6V, a parasitic bipolar transistor formed by the source region/the body layer/the drain region is turned on, to break down the transistor.
In addition, if the accumulated holes are combined with a portion of electrons consisting of a driving current of the transistor when a specific driving current flows, leakage current and operation errors occur.
To preventing the floating body effect, the following three methods are proposed.
A first method prevents the body floating effect by forming a body contact on the MOS transistor and connecting it to ground. However, since a potential of the body layer is maintained at 0V and a voltage of the source region increases in the case of employing the body contact to the MOS transistor, a reverse bias is applied to the source region and the body region respectively, to increase a threshold voltage and to decrease a drain current, thereby deteriorating the performance of the MOS transistor. Furthermore, since the MOS transistor requires an additional region to form the body contact, there is a problem that its size increases
A second method prevents the body floating effect by forming point defects as a life time killer in the source and drain regions. However, as Ar or Ge ions are implanted into the silicon layer by ion-implantation to form the point defects, there is problem in that the surface of the silicon layer is damaged by the ions.
A third method prevents the body floating effect by forming a narrow band gap source in the source and drain regions using a SiGe epitaxial process. However, there is problem in that it is difficult to perform the epitaxial process.

Semiconductor device employing SOI substrate and method of manufacturing the same


A terminal of a plurality of terminals that is located at the farthest position from a host has a return signal generator section, the return signal generator section transmits a return signal at a timing when data transmitted from the host to the terminals arrives at the terminal located at the farthest position, the return signal is returned to the host successively passing through interfaces of the terminals connected to a data bus, and each terminal originates data to be transmitted from the terminal to the host or from the terminal to a particular another terminal in synchronization with the return signal and delivers the data from the terminals to the host or the terminal in synchronization with the return signal.

FIG. 11 is a schematic diagram showing a data transmission path of an IC testing apparatus conventionally used. In this drawing, reference numeral 1 denotes a host computer, reference numeral 1A denotes a data transmitter section in the host computer 1, and reference numeral 1B denotes a data receiver section. Reference numerals 2-1, 2-2, 2-n each denote a terminal that operates under instructions from the host computer 1. In this example of the IC testing apparatus, the terminal 2-1 may serve as a pattern generator section, the terminal 2-2 may serve as a timing generator section, and the terminal 2-n may serve as a test head, for example.
Each terminal 2-1, 2-2, . . . , 2-n has an input/output interface 3, and the interfaces 3 are connected in series to an outgoing data bus line 4. Data addressed to each terminal 2-1, 2-2, . . . , 2-n transmitted over the outgoing data bus line 4 is taken in by the terminal through the interface 3.
Data to be delivered from each terminal 2-1, 2-2, . . . , 2-n to the host computer 1 is output to the outgoing data bus line 4 from the interface 3. The data is transmitted through an incoming data bus line 5 and received by the data receiver section 1B of the host computer 1 and thus taken in by the host computer 1.

Serial transmission system with a return signal generator from the farthest terminal to synchronize return signals/data from the farthest terminal with any specified intervening terminals


Three dimensional silicon structures are fabricated from (100) silicon wafers by a single side, two-step anisotropic etching process using different etchants. The two etch masks are formed one on top of the other on a single side of the wafer prior to the initiation of the two-step etching process, with the mask for the largest and deepest etched recesses formed last and used first. The last formed mask is removed to expose the first formed mask. The anisotropic etchant for the smaller, closer toleranced recesses is chosen to minimize mask etching and improve dimensional control of etched recesses requiring close tolerances and uniform sizes.

This invention relates to a single side, two-step anisotropic etching process for the fabrication of three dimensional devices from silicon, and more particularly, to the use of the this process for fabricating silicon devices having both large recesses and high-tolerance, small recesses, such as for example, the ink flow directing part of a thermal ink jet printhead. A fundamental physical advantage of anisotropic etching in silicon is that the (111) crystal planes etch very slowly while all other crystal planes etch rapidly. Consequently, only rectangles and squares can be generated in (100) silicon material with a high degree of precision. Even with etch masks having only rectangles and squares, the dimensional precision of the etched recesses require that the edges of the mask vias defining the rectangles and squares be aligned with the intersection of the (111) and (100) crystal planes. In the semi-conductor industry, it is common to have silicon devices containing large recesses or through holes in a silicon wafer and relatively shallow high tolerance recess associated with them. For example, an ink jet printhead may be made of a silicon channel plate and a heater plate. Each channel plate has a relatively large ink reservoir etched through the silicon plate so that the open bottom defines an ink inlet and has a set of parallel shallow elongated channel recesses communicating with the reservoir at one end and opened at the other end to form nozzles. The channel recesses require precision geometries with very high tolerances. When the channel plate is aligned and bonded to the heater plate, the large recess becomes the ink reservoir and the shallow elongated channels become the capillary ink conduits between the nozzles and the reservoir, as described more thoroughly in U.S. Pat. No. RE 32,572.
In such printheads, it is frequently desirable to generate a large reservoir which is often etched completely through a 15 to 25 mil thick wafer with small perpendicularly adjacent channels which may be only 1 or 2 mils deep on the same silicon substrate surface. A major difficulty associated with fabrication of such a structure is that the channels and reservoir must be separately etched and then subsequently joined by a variety of methods, such as, for example, the use of a thick film layer on the heater plate that is patterned and etched to form ink flow bypasses. Generally, channel plates are formed by etching a plurality of reservoirs in a (100) silicon wafer first and then accurately aligning the channels to the edge of the reservoir in a second lithographic step followed by etch mask delineation and a second, short anisotropic etch step sufficient to etch the depth of the plurality of sets of associated channels. An advantage of such a process is that control of channel dimension would be very high because the mask defining the channels will be undercut about 1/10th as much as would be the case when the channel and reservoir are delineated simultaneously. This is because the (111) planes have a definite etch rate and the etch time for channels for the two cases is about a factor of 10 different. The problem with such a two-step process is that it is difficult to do a second lithography step on an anisotropically etched wafer due to the large steps and/or etched through holes.
U.S. Pat. No. 4,863,560 to Hawkins, discloses another two-step process for forming three dimensional structures from a silicon substrate by anisotropic etching. In this process, the reservoir and any necessary through holes are formed through a coarse silicon nitride mask as the wafer undergoes a relatively long etching process. Then the nitride mask is stripped to expose a previously patterned high temperature silicon oxide masking layer that is used in a subsequent shorter duration channel etching step. This process avoids the channel width variation problems associated with the previously described single-step process, as the channels are formed during a very short etch duration step. Two problems arise with this process. First, the oxide layer is subject to considerable erosion in some anisotropic etchants, for example, potassium hydroxide. Second, the oxide masking layer is a high temperature thermal oxide process usually carried out at a temperature of about 1,100.degree. C. which can generate high concentration of oxygen precipitant defects in the wafer and disruption of the crystal lattice. Such defects can cause loss of dimensional control, especially of the channels, and result in out of tolerance silicon devices.
Application Ser. No. 07/534,467, entitled "Low Temperature Single Side Multiple Step Etching Process for Fabrication of Small and Large Structure", filed Jun. 7, 1990 to O'Neill, discloses a fabrication process for silicon wafer derived elements, such as channel plates or thermal ink jet printers that include the formation of a final etch pattern in first and second masking layers. The second masking layer is a protective layer to prevent removal of the first layer upon removal of a subsequent third masking layer. Preferably, the second masking layer is an oxide applied under low temperature conditions to lessen the possibility of inducing formation of oxygen precipitates in the wafer. A third masking layer is formed over the final etchant pattern formed by the first and second masking layers. The third masking layer is patterned to form a precursor structure of a large structure contained in the final etchant pattern. After formation of the precursor structure, the third masking layer is removed and the wafer is subjected to a final etching to form the final etched three dimensional structure. The process is useful for forming three dimensional silicon structures, such as channel plates for thermal ink jet printheads.
U.S. Pat. No. 4,875,968 to O'Neill et al., discloses a method of fabricating a thermal ink jet printhead of the type produced by the mating of an anisotropically etched silicon substrate containing ink flow directing recesses with a substrate having heating elements and addressing electrodes thereon. An etch resistant material on the surface of a (100) silicon substrate is patterned to form at least two sets of vias therein having predetermined sizes, shapes and spacing therebetween. The predetermined spacing permits selected complete undercutting by anisotropic etchant within a predetermined etching time period. The patterned silicon substrate is anisotropically etched for the predetermined time period to form at least two sets of separate recesses, each recess being separated from each other by a wall, the surfaces of the walls being (111) crystal planes of the silicon substrate, whereby certain predetermined separately etched recesses are selectively placed into communication with each other by the selective undercutting while the remainder of the undercut walls provides strengthening reinforcement to the printhead, so that larger printheads may be fabricated which are more robust without relinquishing resolution or reducing tolerances. Thus, this patent teaches that certain anisotropic etchants, such as potassium hydroxide, undercuts and etches the etch resistant mask by about 7 micrometers for a full through etch time for a 20 mil thick wafer.
At present, thermal ink jet channel plates are fabricated by two separate potassium hydroxide orientation dependent etching processes or are fabricated by a two-step potassium hydroxide orientation dependent etching process, as disclosed in U.S. Pat. No. 4,863,560. In the latter process, the channel plate reservoir is first etched followed by the etching of the channels. During the second etching step, the masking layer is a thermally grown oxide layer having the disadvantage of being readily etched in the potassium hydroxide etch bath. Thus, the high tolerance, small channel recess must be designed to accommodate not only the undercut of the oxide mask, but the etch removal of the edges of the vias in the mask as well.

Fabrication of three dimensional silicon devices by single side, two-step etching process


Disclosed are a quantum key distribution terminal and system. An optical transceiving device and an electronics media board in a quantum key distribution system are organically integrated into a whole through an electronics back panel. A quantum key distribution terminal with a compact structure and a high integration level is provided, so that uniform testing, maintenance and management for various components in the quantum key distribution system can be realized, thereby realizing the integration and terminalization of the key distribution system. The same quantum key distribution terminal can also be used to conduct flexible networking, thereby setting up a quantum key distribution system on a point to point, local area network or metropolitan area network scale.

With the rapid development of quantum communications technology, quantum key distribution (Quantum Key Distribution, QKD) is becoming a mature applied technology. The technology is based on the no-clone theory and the uncertainty principle in quantum mechanics, and a generated key has a theoretically absolute security and is mainly applied to a scenario requiring a high security level. A conventional quantum key distribution hardware apparatus mainly includes an optical transceiver and an electronics board. The optical transceiver includes a light source board, an light path component and a detector, and the electronics board is mainly used for data processing, key generation and key management.
When the quantum key distribution hardware apparatus is being used, since components of the electronics board and the optical transceiver are independent and separate, multiple signal input/output interfaces of the electronics board are connected to corresponding interfaces of the light source board, the light path component and the detector of the optical transceiver, to form a quantum key distribution system, and the formed quantum key distribution system is applied to practical applications.
Those skilled in the art find the following disadvantages when using the quantum key distribution hardware apparatus:
The electronics board, the light source board, the light path component and the detector included in the quantum key distribution system are placed separately, thus testing, maintenance and management of the whole system are decentralized, and integrated management is hard to realize; and when a quantum key distribution network formed by multiple quantum key distribution systems is being used, networking of the quantum key distribution systems is complicated, and the management and the maintenance are more difficult.

Quantum key distribution terminal and system

SHANGDONG INSTITUTE OF QUANTUM SCIENCE AND TECHNOLOGY CO., LTD.


Biofertilizers have been identified as an alternative to chemical fertilization to increase soil fertility and crop production using sustainable farming. Treatment is with at least a proprietary formulation of a nitrogen-fixing consortium and Azospirillum brasilense. The application of biofertilizers resulted in higher biomass compared to chemical fertilizer treatment. Chlorophyll and nitrogen levels in these grass plants are also likely to be improved.

1. Field of the Invention
The present invention relates to the field of biofertilization and chemical fertilization to increase soil fertility and crop production as an adjunct to sustainable farming technology.
2. Background of the Art
There is a long history of soil fertilization. The term 'fertilization' includes the addition of elements or other materials to the soil to increase or maintain plant yields. Fertilizers may be organic or inorganic. Organic fertilizers are usually manures and waste materials which in addition to providing small amounts of growth elements also serve as conditioners for the soil. Commercial fertilizers are most often inorganic.
Methods of applying fertilizers vary widely and depend on such factors as crop type, stage of growth, application rates, physical and chemical properties of the fertilizer, and soil type. Two basic application methods are used, bulk spreading and precision placement. Time and labor are saved by the practice of bulk spreading, in which the fertilizer is broadcast over the entire area by using large machines which cover many acres in a short time. Precision placement, in which the fertilizer is applied in one or more bands in a definite relationship to the seed or plants, requires different equipment and time, but usually smaller amounts of fertilizer are needed to produce a given yield increase.
For some deep-rooted plants, subsoil fertilization to depths of 12-20 in. (30-50 cm) is advantageous. This is usually a separate operation from planting, and uses a modified subsoil plow followed by equipment to bed soil over the plow furrow, thereby eliminating rough soil conditions unfavorable for good seed germination. Top-dressings are usually applied by broadcasting over the soil surface for closely spaced crops such as small grains.
Nonvolatile fertilizer solutions are often pumped into the supply lines of irrigation systems to allow simultaneous fertilization and irrigation. With the exception of bulk spreaders and other broadcasters, most fertilizer application devices are built as attachments which can be mounted in conjunction with planters, cultivators, and herbicide applicators. Often the tanks, pumps, and controls used for liquid fertilizers are also used for applying other chemicals such as insecticides.
One of the major problems with these types of chemical fertilization is the fact that there are harmful effects of chemical fertilizers and their impact on the environment through nitrate contamination of ground and run-off waters. The sheer volume of fertilizers added to the soil each year is itself a major contamination problem, even if the fertilizing effects are immediately beneficial in some perspectives. It is reported that, in the United States, generally, 50% of chemical fertilizer applied to soil bypasses utilization in the soil, runs off, usually untreated, in ground water, and end up in aquifers where it represents, among other problems, a public health hazard. Alternatives to mass application chemical fertilization are therefore extremely desirable.
Biofertilizers (fertilization compositions comprising microbes) have been identified as an alternative to chemical fertilization to increase soil fertility and crop production using sustainable farming. The use of nitrogen-fixing bacteria provides plants with nitrogen compounds needed for growth and there is increasing evidence that other bacteria provide plant hormones to enhance growth.
Turf grass uses large amounts of nitrogen in the production of needed organic compounds. Most atmospheric, nitrogen is metabolically unavailable to plants and animals. The only exceptions occur when certain species of bacteria are capable of fixing atmospheric nitrogen creating organic, nitrogen-containing compounds. Bacteria with this capability are called diazotrophs. Associative nitrogen-fixing bacteria reside in close proximity to plant roots where they make a contribution of biologically available nitrogen to plants and plants to provide nutrients to the nitrogen-fixing bacteria. In addition to nitrogen fixation, Azospirillum brasilense produces plant growth hormones which have been shown to increase the number of lateral roots and root hairs (Tien, et al., 1979). These two additions could explain the increased total plant weight in the UNLV Biofertilizer treatment groups.
For the Biofertilizer, there is possibly a critical, minimum population size of diazotrophic bacteria needed for significant rates of nitrogen fixation (Wright, et al., 1981). Nitrogen fixation rates are linked to microbial growth and dependent on plant cell proliferation (National Research Council, 1994). It is known that certain strains of diazotrophs, known to be efficient fixers of nitrogen, when inoculated into the soil do not compete well against the diazotrophs already present in the soil, reducing the inoculation benefit.
U.S. Pat. No. 6,495,362 (Nautiyal) describes a biologically pure culture of bacteria that suppresses diseases caused by pathogens in chickpea crops and a culture of bacteria comprising a strain of Pseudomonas fluorescens. The patent discloses a simple live-sand or soil assay method for large scale screening of the rhizosphere-competent bacteria effective in suppressing plant pathogens. Screening for chickpea rhizosphere competitive bacteria having biological control properties were conducted at three different stages: (1) development of a screening method for large scale initial selection of bacterial isolates from chickpea rhizosphere, (2) testing of biocontrol activity under in vitro conditions, and (3) screening of antibiotic resistant mutants for rhizosphere competence in nonsterile field soil, which assay is used to disclose one Pseudomonas fluorescens NBRI 1303 (ATCC 55939) which is effective in suppressing plant pathogens, including Fusarium oxysporum f. sp. ciceri, Rhizoctonia bataticola and Phthium sp. in chickpeas, and the purified bacterial strain can be used as active agent for biocontrol compositions and can also be used for enhancement of chickpea plant growth and yield, as well as for the production of antibiotics directed towards phytopathogenic fungal diseases. The reference discloses that P. fluorescens NBRI 1303 (ATCC 55939) is an aggressive chickpea rhizosphere colonizer and can survive in the field at temperatures in the range of 0° C. to 55° C. In addition, this bacterial strain appears to produce one or more antifungal metabolites which inhibit the growth of pathogenic fungi F. oxysporum f. sp. ciceri, R. bataticola and Pythium sp. or other fungal pathogens of chickpeas since the culture supernatant exhibits growth inhibitory effects for pathogenic fungi F. oxysporum f. sp. ciceri, R. bataticola and Pythium sp. A greenhouse test and field trial of P. fluorescens demonstrated the usefulness of the strain as an inoculum for improved plant performance and therefore P. fluorescens may be used as a biocontrol agent.
Various strains of saprophytic soil bacteria are known to influence plant growth in different types of plants. For example, the inoculation of nonleguminous crops with selected strains of free-living, nitrogen-fixing species of Azotobacter and Azospirillum can cause significant increases in crop yield under field conditions. Kapulnik et al. (1981); Brown (1974). But bacteria of these genera are generally unable to compete adequately with native flora to assure multiplication. When used in seed inoculants, moreover, they are not "root colonizers," i.e., they are incapable of transferring in large numbers from seed to roots and, consequently, cannot keep pace with developing roots. See, e.g., Reynlers & Vlassak (1982). As a consequence, impractically large amounts of inoculum are required to obtain a meaningful effect on plant growth.
Y. Kapulnik et al. inoculation of Azospirillium brasilense in Spring wheat, Biology an Fertility of Soils© Springer-Verlag 1987 Biol Fertil Soils (1987) 4:27-35 shows very limited utility for Azosprillium brasilense in treatment of Spring Wheat and especially Miriam Spring Wheat, while finding inconclusive or neutral results for other wheats.
The mechanism(s) by which soil bacteria may influence plant growth has been the subject of extensive investigation. Research into the role of microbial iron transport agents (siderophores) in the root zones of plants (the "rhizosphere") is one mechanism by which some fluorescent pseudomonad species promote plant growth, namely, by antagonism (antibiosis, competition or exploitation) to deleterious indigenous microorganisms, resulting in their exclusion from roots.
Canadian patent No. 1,172,585 discloses the use of particular strains of naturally-occurring pseudomonads to benefit plant growth in root crops by reducing the population of other indigenous root-zone microbiota that adversely influence plant growth. Similarly, the results of one study indicated that growth-promotion in radish and potato by rhizobacteria did not occur under gnotobiotic conditions, when competition between other strains was not a factor, and hence, that rhizobacteria promote plant growth indirectly, by interaction of the rhizobacteria with native root microflora, rather than directly by microbial production of growth-promoting substances.
Another proposed mechanism for plant growth promotion by soil bacteria involves a direct stimulation of growth by bacterial elaboration of substances like nitrogen, plant hormones such as auxins and giberellins, and compounds that promote the mineralization of phosphates. But the hypothesis that elaboration of bacterial products is related to enhanced growth in plants has lacked definitive supporting data.
For example, investigations of root-elongation promotion in grasses by an auxin-overproducer mutant of Azospirillum prompted the conclusion that observed levels of the bacterially-produced auxin bore no direct relation to the root elongation. Using a petri plate bioassay for root elongation in wheat, Kapulnik et al (1985) found that seed inoculation with an A. brasilense strain resulted in root elongation in one bacterial concentration range but inhibition of root development in another, higher range. Kapulnik et al also reported that A. brasilense supernatants did not affect root length, a result arguing against a substantial role for a bacterial product in promoting root elongation. A screening of rhizosphere bacterial metabolites for in situ effects on seedling root development likewise yielded mixed results, with the observed effects ranging from complete inhibition to unaffected development; notably, no growth stimulation per se was reported.
The term "root-colonizing" is used to denote bacteria, including rhizospheric and non-rhizospheric strains, that can transfer from seed (as an inoculum component) to roots developing from the seed, and are able to maintain a stable association with the root system of the plant as it grows.
U.S. Pat. No. 6,878,179 (Porubcan) discloses fertilizer compositions for plant production comprised of decontaminated manure and Bacillus spores, preferably a humic acid derived from lignite and, optionally, one or more N-containing compounds, P-containing compounds, K-containing compounds, and combinations of two or more of these compounds. Preferred compositions are those wherein the ingredients are blended into an admixture resulting in a granular product. Other preferred compositions are those blended into an admixture resulting in a powdered product. Preferably, the ingredients are formed into hardened prills or pellets. Processes for production and use are also presented.
U.S. Pat. No. 6,228,806 (Mehta) describes a biochemical fertilizer. A broad list of microorganisms, listed by genera, is provided, including Bacillus. The need for microbial nutrients is mentioned as part of the microorganism ingredient, not the bulk organic ingredient
U.S. Pat. No. 6,312,492 (Wilson) discloses improved fertilizer effect of poultry manure by adding sulfuric acid followed by drying. Wilson teaches specifically the co-addition of cellulose containing materials.
U.S. Pat. No. 6,232,270 (Branly et al.) focuses on using Bacillus bacteria to enhance the effectiveness of chemical herbicides and lists every imaginable Bacillus ever discovered, and claims they will all benefit this purpose.
U.S. Pat. No. 5,702,701 (O'Donnell) describes the use of a unique strain of Bacillus laterosporus (BOD strain) to benefit plants.
U.S. Pat. No. 6,174,472 describes a process of forming a pellet comprised of at least sixty percent (60%) composted sewer sludge, up to forty percent (40%) cellulosic plant material and up to fifteen percent (15%) nutrient materials and chemicals for soil enhancement and plant nutrition that provides a combination of both long and short term beneficiation of soil and herbage and has no pathogenic microbes above regulatory ranges. The composted sewer sludge comprises primary sewer sludge admixed with cellulosic plant material that is thermally treated at temperatures between 140 and 180° F. during composting to destroy mesophyllic pathogenic microbes and the viability of reproducible botanicals including seeds, but leave most thermophilic soil enhancing microbes in a viable state. Additional fibrous cellulosic material and chemicals are admixed with the composted sewer sludge and the mixture pelletized in a thermal process that raises pellet temperature to between 140 to 180° F. The nutrient and chemical materials selectively comprise nitrogenous fertilizers, phosphate, potash, trace elements, herbicides, insecticides and botanical chemicals.
U.S. Pat. No. 6,025,187 describes bacterial complexes comprising at least one non-pathogenic Bacillus and at least one non-pathogenic Lactobacillus which essentially allow the conversion of inorganic nitrogen into organic nitrogen in the form of bacterial proteins, which allow the conversion of excrement into nitrogenous compounds (stable nitrogenous compounds and/or compost) and, particularly for waste having a sufficient C/N ratio (in relation to the level of solids content), into non-polluting compounds rich in fulvic acid and humic acid, by digestion and conversion of excrements, while at the same time removing the associated pathogenic germs, in particular Clostridium, Bacteroides, colibacilli, Listeria, salmonellae and staphylococci.

Biofertilizer for treatment to improve growth of turf grass and method of developing the biofertilizer

The Board of Regents of the Nevada System of Higher Education on Behalf of the University of Las Vegas, Nevada


A bulldozer blade (10) is automatically reset to a predetermined excavating pitch while the bulldozer (20) is traveling backwardly after it has completed an operation of excavating, carrying, or dumping earth. The bulldozer blade (10) can be set to an excavating pitch, a carrying pitch, or a dumping pitch when excavating, carrying, or dumping earth while the bulldozer is traveling forwardly, the bulldozer blade being attached to the leading ends of frame members (15A, 15B) which are pivotally mounted on opposite sides of the vehicle body (20a) in such a manner that the bulldozer blade can swing longitudinally. The rotational angles of left and right lifting cylinders (21A, 21B), which are attached to the bulldozer blade, are detected by first detectors (23a, 23b) while the bulldozer is traveling backwardly after it has completed an operation of excavating, carrying, or dumping earth, and the bulldozer blade is automatically reset to a predetermined excavating pitch from the carrying pitch or the dumping pitch in response to a command issued by a controller (50) which receives detection signals from the first detectors.

1. Field of the Invention
The present invention relates to a bulldozer blade pitch control method and a controller for the same, for automatically resetting a bulldozer blade to a predetermined excavating pitch while the bulldozer is traveling backwardly after the bulldozer has completed an operation of excavating, carrying, or dumping earth.
2. Description of Related Art
As shown in FIG. 3, a bulldozer 20, which is equipped with a bulldozer blade 10, has a left frame member 15A and a right frame member 15B which are pivotally attached to the right and left sides of the vehicle body 20a of the bulldozer 20 such that they can swing, the bulldozer blade 10 being pivotally installed on the leading ends of the frame members 15A and 15B so that the bulldozer blade 10 can swing longitudinally. The left end portion of the bulldozer blade 10 is pivotally connected to one end of the left pitching cylinder 20A, while the other end of the left pitching cylinder 20A is connected to an intermediate portion of the left frame member 15A. Similarly, the right end portion of the bulldozer blade 10 is pivotally connected to one end of the right pitching cylinder 20B, while the other end of the right pitching cylinder 20B is connected to an intermediate portion of the right frame member 15B.
The left portion of the bulldozer blade 10 is also pivotally connected to the left front portion of the vehicle body 20a by the left lifting cylinder 21A, while the right portion of the bulldozer blade 10 is also pivotally connected to the right front portion of the vehicle body 20b by the right lifting cylinder 21B. The lifting cylinders 21A and 21B can be extended or retracted simultaneously so as to raise or lower the bulldozer blade 10 as indicated by the arrow A in FIG. 3. The pitching cylinders 20A and 20B can be extended or retracted simultaneously to pitch the bulldozer blade 10 forwardly for dumping or backwardly as indicated by the arrow B in FIG. 3.
In a conventional bulldozer, for example, as proposed in Japanese Unexamined Utility Model Publication No. 3-50646, the bulldozer blade is raised, lowered, and pitched by a single control lever and a single tilting or pitching selector switch.
When the bulldozer excavates while traveling forwardly, the bulldozer blade is pitched at an excavation angle. When the bulldozer carries earth while traveling forwardly, the bulldozer blade is pitched backwardly from the excavating angle to a carrying pitch, also known as a back pitch. The term "earth" is considered to be generic to dirt, sand, rocks, debris, etc., which can be excavated and carried by a bulldozer. When the bulldozer dumps earth while traveling forwardly, the bulldozer blade is forwardly from the excavating angle to a dumping pitch. However, when an operator of the bulldozer returns to an original excavating point by traveling the bulldozer backwardly after completing such carrying or dumping work, the operator is required to simultaneously operate both the control lever for steering the bulldozer and a working machine lever for resetting the bulldozer blade to the original excavating pitch. This makes the operation complicated, which is undesirable from a safety standpoint.

Bulldozer blade pitch control method and controller for the same