Providing visual feedback of balancing of programming structure hierarchy in a program entered on a programmable device having a processor, an instruction memory, an input device, and a display screen having a left edge. In an arrangement, at least two control structure opening statements are received, each having an associated control structure. A unique representation is assigned to each of the at least two control structures. The control structure opening statements are displayed in the unique representation assigned to the corresponding control structure beginning at a same location with respect to the left edge of the display. At least two control structure closing sequences are received, and each control structure closing sequence is associated with one of the control structures, respectively.

Structured programming is a programming methodology in which programs are written using control structures and basic blocks. The control structures, which include conditional branches and loops, determine the flow of control through a program during execution of the program.
Correct programming requires adherence to grammatical rules of a selected programming language. Control structures are opened and closed according to the syntactic rules of the programming language.
Failing to balance a control structure opening statement with a corresponding closing statement can also cause a program not to execute as expected.
To facilitate understanding of a program, indentation is usually used to illustrate statements that fall within a conditional statement of a loop.
Modern programming environments, often referred to as integrated development environments (IDE) or integrated programming environments (IPE) (herein, the abbreviation "IDE" is used to include both IDE and IPE), provide program entry and editing tools that automate many tasks of a programmer. One example is the automatic indentation of program code as the code is entered by a programmer or read from program memory.
On large screens, such as found on computer workstations as well as modern notebook computers and tablets, windows displaying program code can usually be expanded to sufficient width to accommodate code that has a high level of nesting of control structures and that has the associated deep indentation. However, on smaller screens, for example, hand-held devices such as on programmable calculators, the indentation presents a problem. If a program contains lines that extend beyond the right edge of the device screen, the line is typically either wrapped to the next line, or the display screen can be scrolled horizontally to allow a reader to read the entire line. Both solutions cause a loss of readability of the program and defeat the purpose of indenting the code for readability.

Programmable device providing visual feedback of balancing of opening and closing statements of programming structures and nesting level


Described is a composite polymeric system to provide enhanced stimuli-responsiveness. The first aspect provides particles where the particles are made of stimuli-responsive polymer which responds to various stimuli such as temperature and pH change. Incorporated with this particle is a second polymer which in turn is relatively insensitive to stimuli. The invention can be potentially applied to other systems comprising a swellable hydrogel and a nonswellable hydrophobic polymer.

The present invention relates to a polymeric system, and more particularly to a system which releases drugs in response to environmental stimuli or separates solutes.
The human body has its own homeostatic mechanisms to regulate a variety of physiologic parameters within a certain range. These parameters include temperature, pH and salt content. In instances of disease, however, these parameters may be affected due to various mechanisms. It is essential that the body maintain homeostasis for proper conditions for enzyme reactions and metabolism to be carried.
In infection, the interactions between polymorphonuclear cells and bacteria may result in the production of pyrogens. These pyrogens may disrupt the thermo-regulatory system located in the hypothalamus of the mid-ventricle in the brain resulting in an elevation of the temperature threshold and the normal body temperature. (1) Also, in localized inflammation, the immune system of the body responds with an increase in vasodilation and release of many inflammatory mediators. Histamine, for example, results in an increase in vasodilation and consequently, the permeability of capillaries increases (2) with resulting edema. Sites of inflammation also manifest with an increase in temperature. Products of reactions resulting from inflammation are usually acidic. Therefore, the pH of the local area is reduced.(3)
In tumors, research has demonstrated that the intracellular region is of a lower pH than the extracellular region.(4) Hyperthermia has also been studied as an adjunct in cancer chemotherapy. It was found that tumor cells were more sensitized to chemotherapeutic agents when heat was applied locally to the tumor site.(5)
Regulated drug delivery, or more appropriately called, stimuli-responsive drug delivery, is a concept in which a drug or drugs is/are delivered at an appropriate rate in response to stimuli. As aforementioned, disease states may cause a change in some parameters of the body and this can be used as a stimuli or a xe2x80x9ctriggerxe2x80x9d for the onset and offset of the delivery of drugs. Certain polymers exhibit property changes in response to variations in temperature, and pH. A number of these polymers have been investigated extensively and some success in drug delivery with them has been achieved. For example, polymers loaded with glucose oxidase have been used for regulated delivery of insulin according to the amount of glucose in the body. The glucose reacts with glucose oxidase producing an acid which induce the swelling of the polymer thus increasing the release of insulin.(6) Thermosensitive polymers such as poly(N-isopropylacrylamide) (PNIPAm) have also been used for regulated drug delivery. Such polymers experience a dramatic change in hydration when the temperature is increased or decreased through the phase transition temperature (Ttr). At T less than Ttr, the polymers swell and release more drug; at T greater than Ttr, the polymers collapse resulting in a decrease in release rate due to the formation of dense skin following a pulsatile release at the initial stage.(7) However, in light of this, type of delivery system suffers from negative thermosensitivity, i.e., which is in the opposite direction of the slow of therapeutic agents associated with hyperthermia. In addition the system has the disadvantages of slow response and low mechanical strength.
To overcome these problems, several new designs of thermosensitive delivery systems have been developed.(8-13) These include a hydrogel-valve cylindrical device (14) and various membrane systems. Positive thermoresponse (i.e., higher release rate at higher temperature) has been obtained and mechanical strength has been improved in these systems. However, their application is limited by the methods of fabrication. For example, one is a cylindrical device with a hard plastic shell in which a drug solution is enclosed. The release of the drug solution is controlled by a piece of hydrogel which changes volume with temperature. Unfortunately, the volume change of the hydrogel is rather slow because of its size. Moreover, the device, with a rigid shape, requires surgery for introduction and removal from the body.
Existing membrane systems that exhibit positive thermosensitivity are prepared by chemical reactions such as cross-linking, grafting or radical polymerization.(8-13) Therefore, purification is required after the fabrication of the membrane. More importantly, and a clear disadvantage of such systems is that the reaction conditions are hazardous for therapeutic agents, especially those biological products such as proteins and peptides.
The human body is known to exhibit certain circadian rhythms according to different times of day. It has been found that for some anti-cancer agents, their toxicity can be minimized if the drug is administered at a certain time of the biological clock. Tumor cells are found to multiply at different rates during different time of the day. They are also known to follow a circadian rhythm. Clinical trials have demonstrated that therapeutic agents administered according to circadian rhythms are more effective and less toxic than the standard schedule of therapy.(15) Therefore, pulsatile delivery of drugs may be advantageous over the constant delivery.
With the development of recombinant DNA technology in the production of proteins and peptides, more and more new protein and peptide drugs are synthesized. In biotechnological processes such as fermentation, a number of peptides may be produced in one batch. These processes require further purification of the products.(16) Therefore, it is necessary to design a membrane that can separate a series of compounds of various molecular weights.
In vivo instability especially enzymatic degradation, hinders application of proteins and polypeptides as therapeutic agents. As such it is desirable to have a delivery system that can allow therapeutic agents to diffuse out while preventing the enzymes from entering.
This invention involves the development of a composite polymeric system containing stimuli-responsive particles and at least one other polymer. As used herein, the term xe2x80x9cparticlesxe2x80x9d includes nano- or microspheres, or any other particles having dimensions within the range from nanometeres to millimeteres. The system and particles can be of any shape. This new system can be made to be biocompatable and can be biodegradable. The system can change pore size quickly in response to external stimuli such as pH, temperature, ionic strength, multivalent ions, and other chemicals, i.e., it is stimuli-responsive and consequently it can provide stimuli-responsive drug release. Further, pore size of the system can be tailored for release and/or separation of solutes of different sizes. It can also protect protein and polypeptide drugs from enzymatic degradation.
Broadly stated, the present invention relates to a composite polymer system comprising stimuli-responsive particles, preferrably nano- or microspheres, and at least one other polymer. The xe2x80x9cat least one other polymerxe2x80x9d is referred to herein as a second polymer. Second polymer can be one or more other polymers, i.e., one, two three or more xe2x80x9csecond polymersxe2x80x9d. The invention provides a polymeric system which strengthens the mechanical strength of a responsive component using at least one other polymer, i.e., second polymer which acts as a matrix and to increase the response rate of the system. A responsive component such as PNIPAm/MAA nanoparticles act as responsive nanovalves which can form channels in response to changes in external stimuli like temperature and pH. This invention can potentially be applied to other systems comprising a swellable hydrogel and nonswellable hydrophobic polymer.
Accordingly, the present invention provides a composition for a composite polymer system comprising a stimuli-responsive polymer, preferrably swellable, and at least one second polymer, preferrably non-swellable and hydrophobic.
According to a preferred embodiment the stimuli-responsive polymer is selected from the group consisting of R-acrylamide, R1-acrylate, R2-acrylic acid, and polyethylene glycol where R, R1, and R2 may each be H or alkyl.
According to another preferred embodiment the second polymer is selected from the group consisting of polysaccharides, polysaccharide derivatives, cellulose, cellulose derivatives, polyesters; anhydrides; poly(orthoesters); and polyurethane. Most preferably a composition according to this invention is biocompatable and biodegradable. A preferred embodiment is a composite polymer system comprising poly(N-isopropylacrylamide-co-methacrylic acid) and ethylcellulose.
The invention also broadly contemplates methods for preparing composite polymeric systems of the present invention containing stimuli-responsive particles, preferrably nano- or microspheres, and at least one second polymer as follows:
(a) obtaining particles with suitable responsive properties and sizes;
(b) mixing the particles with at least one second polymer solution;
(c) casting the composite polymer system. The system can be case in any shape which is desired or appropriate depending upon the application.
Accordingly, the present invention provides a method of preparing composite polymer system, preferrably with particles that are nano or microspheres comprising: (a) preparing particles with a stimuli-responsive polymer; (b) adding and mixing at least one second polymer, preferrably non-swellable and hydrophobic, under conditions which permit dispersion of the particles in the second polymer; and (c) casting the resulting composite polymer system.
According to a preferred method the stimuli-responsive polymer is selected from the group consisting of R-acrylamide, R1-acrylate, R2-acrylic acid, and polyethylene glycol where R, R1, and R2 may each be H or alkyl.
According to a further preferred method the second polymer is selected from the group consisting of polysaccharides, polysaccharide derivatives, cellulose, cellulose derivatives, polyesters; anhydrides; poly(orthoesters); and polyurethane.
According to preferred embodiments the step of mixing is carried out by melting the polymers or mixing them in solution.
The composite polymeric systems of the present invention may also be used in any one or more of the following applications: solute separation and filtration; temperature, pH and ionic strength and biochemical ionsxe2x80x94responsive drug delivery; diagnostic and monitoring tools; protein and peptide drug delivery; and coating and microencapsulation of solid dosage forms such as tablets, or microencapsulation of live cells.
According to further embodiments of the present invention the particles may also be used for treating inflammation, infection, diabetes, arthritis, and cancer, as well as a method for stimuli-responsive separation of solutes of different sizes in an aqueous medium.
Other features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples while indicating preferred embodiments of the invention are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Polymeric system for drug delivery and solute separation


Methods and apparatuses for planarizing a microelectronic substrate. In one aspect of the invention, a first portion of an energy-sensitive, non-sacrificial planarizing pad material is exposed to a selected energy without exposing a second portion of the material to the selected energy source. The planarizing pad material is exposed to a solvent to remove material from one of the first or second portions of the planarizing pad material at a faster rate than removing material from the other of the first and second portions. The process forms a plurality of recesses directly in the surface of the planarizing pad which are configured to support a planarizing liquid proximate to the surface of the planarizing pad material during planarization of the microelectronic substrate. Alternatively, the process can form a mold having protrusions that are pressed into the planarizing pad to define the recesses in the pad.

This invention relates to planarizing pads and to methods and apparatuses for forming and using planarizing pads, such as disposable and/or conditionless planarizing pads for mechanical and chemical-mechanical planarization of microelectronic substrates.
Mechanical and chemical-mechanical planarization processes (xe2x80x9cCMPxe2x80x9d) are used in the manufacturing of electronic devices for forming a flat surface on semiconductor wafers, field emission displays and many other microelectronic-device substrate assemblies. CMP processes generally remove material from a substrate assembly to create a highly planar surface at a precise elevation in the layers of material on the substrate assembly. FIG. 1 schematically illustrates an existing web-format planarizing machine 10 for planarizing a substrate 12. The planarizing machine 10 has a support table 14 with a top-panel 16 at a workstation where an operative portion (A) of a planarizing pad 40 is positioned. The top-panel 16 is generally a rigid plate to provide a flat, solid surface to which a particular section of the planarizing pad 40 may be secured during planarization.
The planarizing machine 10 also has a plurality of rollers to guide, position and hold the planarizing pad 40 over the top-panel 16. The rollers include a supply roller 20, first and second idler rollers 21a and 21b, first and second guide rollers 22a and 22b, and take-up roller 23. The supply roller 20 carries an unused or pre-operative portion of the planarizing pad 40, and the take-up roller 23 carries a used or post-operative portion of the planarizing pad 40. Additionally, the first idler roller 21a and the first guide roller 22a stretch the planarizing pad 40 over the top-panel 16 to hold the planarizing pad 40 stationary during operation. A motor (not shown) drives at least one of the supply roller 20 and the take-up roller 23 to sequentially advance the planarizing pad 40 across the top-panel 16. Accordingly, clean pre-operative sections of the planarizing pad 40 may be quickly substituted for used sections to provide a consistent surface for planarizing and/or cleaning the substrate 12.
The web-format planarizing machine 10 also has a carrier assembly 30 that controls and protects the substrate 12 during planarization. The carrier assembly 30 generally has a substrate holder 32 to pick up, hold and release the substrate 12 at appropriate stages of the planarizing process. Several nozzles 33 attached to the substrate holder 32 dispense a planarizing solution 44 onto a planarizing surface 42 of the planarizing pad 40. The carrier assembly 30 also generally has a support gantry 34 carrying a drive assembly 35 that translates along the gantry 34. The drive assembly 35 generally has an actuator 36, a drive shaft 37 coupled to the actuator 36, and an arm 38 projecting from the drive shaft 37. The arm 38 carries the substrate holder 32 via a terminal shaft 39 such that the drive assembly 35 orbits the substrate holder 32 about an axis Bxe2x80x94B (as indicated by arrow R1). The terminal shaft 39 may also rotate the substrate holder 32 about its central axis Cxe2x80x94C (as indicated by arrow R2).
The planarizing pad 40 and the planarizing solution 44 define a planarizing medium that mechanically and/or chemically-mechanically removes material from the surface of the substrate 12. The planarizing pad 40 used in the web-format planarizing machine 10 is typically a fixed-abrasive planarizing pad in which abrasive particles are fixedly bonded to a suspension material. In fixed-abrasive applications, the planarizing solution is a xe2x80x9cclean solutionxe2x80x9d without abrasive particles because the abrasive particles are fixedly distributed across the planarizing.surface 42 of the planarizing pad 40. In other applications, the planarizing pad 40 may be a non-abrasive pad without abrasive particles, composed of a polymeric material (e.g., polyurethane) or other suitable materials. The planarizing solutions 44 used with the non-abrasive planarizing pads are typically CMP slurries with abrasive particles and chemicals to remove material from a substrate.
To planarize the substrate 12 with the planarizing machine 10, the carrier assembly 30 presses the substrate 12 against the planarizing surface 42 of the planarizing pad 40 in the presence of the planarizing solution 44. The drive assembly 35 then orbits the substrate holder 32 about the axis Bxe2x80x94B and optionally rotates the substrate holder 32 about the axis Cxe2x80x94C to translate the substrate 12 across the planarizing surface 42. As a result, the abrasive particles and/or the chemicals in the planarizing medium remove material from the surface of the substrate 12.
The CMP processes should consistently and accurately produce a uniformly planar surface on the substrate assembly to enable precise fabrication of circuits and photo-patterns. During the fabrication of transistors, contacts, interconnects and other features, many substrate assemblies develop large xe2x80x9cstep heightsxe2x80x9d that create a highly topographic surface across the substrate assembly. Yet, as the density of integrated circuits increases, it is necessary to have a planar substrate surface at several intermediate stages during substrate assembly processing because non-uniform substrate surfaces significantly increase the difficulty of forming sub-micron features. For example, it is difficult to accurately focus photo patterns to within tolerances approaching 0.1 micron on non-uniform substrate surfaces because sub-micron photolithographic equipment generally has a very limited depth of field. Thus, CMP processes are often used to transform a topographical substrate surface into a highly uniform, planar substrate surface.
One problem with conventional CMP methods is that the planarizing surface 42 of the planarizing pad 40 can become glazed with accumulations of slurry and/or material removed from the substrate 12 or the planarizing pad 40. One conventional approach to addressing this problem is to remove the accumulations by conditioning the planarizing pad 40, for example, by abrading the planarizing pad 40 with an abrasive disk (not shown). A drawback with this approach is that the equipment required for conditioning the planarizing pad 40 adds complexity to the planarizing machine 10 and, if the conditioning operation is performed separately from the planarizing operation, it reduces the time that the planarizing pad 40 is available for planarizing. Conventional conditioning processes can thus limit the overall efficiency of the apparatus.
One approach to address this drawback is to eliminate the need to condition the pad by making the planarizing surface or the entire planarizing pad disposable. For example, U.S. application Ser. No. 09/001,333 discloses a disposable planarizing pad film made from materials such as Mylar or polycarbonate. The pads disclosed in Application Ser. No. 09/001,333 can have microfeatures of different heights that entrap small volumes of an abrasive slurry and maintain the slurry in contact with the substrate. The microfeatures can be formed using a variety of techniques, such as embossing or photo-patterning.
One conventional method for photo-patterning is shown schematically in FIGS. 2A-2E. As shown in FIG. 2A, a photopolymer composite 50 is formed by disposing a photopolymer resist material 53 on a substrate polymer 52 which is supported by support layer 51. The photopolymer resist material 53 is then exposed to a radiation source 63. A mask 60 having opaque portions 61 and transmissive portions 62 blocks the radiation emitted from the radiation source 63 from striking unexposed portions 55 of the photopolymer resist material 53, while allowing the radiation to strike exposed portions 54.
As shown schematically in FIG. 2B, the exposed portions 54 change chemical characteristics as a result of being exposed to the radiation source 63. For example, when the photopolymer resist material 53 is initially soluble in a selected solvent, exposure to the selected radiation can change the exposed portions 54 to become insoluble in the selected solvent. Alternatively, when the photopolymer resist material is initially insoluble in the selected solvent, exposure to the selected radiation can make the exposed portions 54 soluble. In either case, the solubility of the unexposed portions 55 remains unchanged.
When the exposed portions 54 are rendered insoluble by exposure to the selected radiation, FIG. 2C schematically illustrates the photopolymer composite 50 after being rinsed with the selected solvent. The exposed portions 54 of the photopolymer resist material 53 remain intact and the unexposed portions have been removed by the solvent to expose the substrate polymer 52 below. The substrate polymer 52 is then etched to remove the portions of the substrate polymer material from between the exposed portions 54 of the photopolymer resist material 53 and form recesses 70, as is shown in FIG. 2D. The exposed portions 54 of the photopolymer resist material 53 are then removed, leaving the finished article (shown in FIG. 2E) having protrusions 76 separated by the recesses 70.
One drawback with the method discussed above with reference to FIGS. 2A-2E is that separate steps are required to place the photopolymer resist material 53 on the substrate polymer 52 and remove the photopolymer resist material 53 from the substrate polymer 52 after the recesses 70 are formed. Furthermore, the solvent that removes the photopolymer resist material 53 may be different than the solvent that removes the underlying substrate polymer 52, requiring the manufacturer to keep multiple solvents on hand.
One method for reducing the number of manufacturing steps and solvents associated with photoresistive techniques used in the printing industry is to etch the recesses 70 directly in a photosensitive material. For example, Cyrel(copyright), available from E.I. du Pont de Nemours and Co. of Wilmington, Del., is used to make printing plates by forming surface features directly in a photosensitive material without separately etching the material below. However, such printing plates are generally unsuitable for application to planarizing pads because the surfaces of the plates have deep recesses that separate inked regions from non-inked regions of the plates to prevent blurring of the resulting image. These deep recesses will not adequately support the planarizing liquid adjacent to the surface of a microelectronic substrate, reducing the effectiveness of the planarizing pad.
The present invention is directed toward planarizing pads for planarizing microelectronic substrates, methods for forming planarizing pads, and methods for planarizing the microelectronic substrates. In one aspect of the invention, the planarizing pad is formed by exposing a first portion of a surface of an energy-sensitive, non-sacrificial planarizing pad material to a selected energy source without exposing a second portion of the surface (adjacent to the first portion) to the selected radiation energy source. The method can further include exposing the planarizing pad material to a solvent to remove material from one of the first and second portions of the planarizing pad material at a greater rate than removing material from the other of the first and second portions. The process forms a plurality of recesses directly in the surface of the planarizing pad material, with the recesses configured to support a planarizing liquid proximate to the surface of the planarizing pad material during planarization of the microelectronic substrate.
The planarizing pad can have a variety of shapes and features. For example, the planarizing pad can be elongated and can extend between a supply roller and a take-up roller for use with a web-format planarizing machine. Alternatively, the planarizing pad can have a circular planform shape for use with a conventional rotary format planarizing machine. In either of these embodiments, the planarizing pad can have abrasive elements fixedly disbursed therein and/or can be used with a planarizing liquid having a suspension of abrasive particles.
In another aspect of the invention, the steps discussed above with respect to the radiation-sensitive planarizing pad material can be used to process a radiation-sensitive mold material into a mold. The mold can be wrapped around a roller which rotates to engage the planarizing pad material and emboss the planarizing pad material with recesses and texture elements, or the mold can have a flat shape which presses against the planarizing pad material to form recesses and texture elements in the planarizing pad material.

Method and apparatus for forming and using planarizing pads for mechanical and chemical-mechanical planarization of microelectronic substrates


A highly compact and lightweight 82 channel all band VHF-UHF television antenna having three antenna elements wherein each element is the identical physical length and each element includes two half sections. Each antenna element is separated a predetermined distance from each other element wherein the predetermined distance is substantially less than one-tenth of the shortest wave length in the VHF band. A first set of coils are utilized to electrically lengthen the halves of the two elements for reception in the VHF band and a second set of coils are utilized to provide proper delays between the signals received by each antenna element so that when the signals are combined the signals are substantially additive and in phase. The antenna system includes a weatherproof housing containing a rotor, a preamplifier, and electronic circuitry. A deloading mechanism is arranged around the housing to engage the circumference of each antenna element to provide stability under the driving forces that may occur in the atmosphere.

1. Field of Invention
This invention relates to a highly compact all-channel television antenna. More particularly, it relates to an all-channel television antenna having the antenna elements the same physical length.
2. Discussion of the Prior Art
Over the past several decades, the art of television antenna design has become quite sophisticated. Two general consumer categories of antennas have evolved. The first category contains the "multi-element" UHF-VHF large antennas which typically comprise numerous elements in each antenna in order to improve the gain and directivity of the television signal across the 82 channel VHF-UHF bands. Examples of such prior art approaches are:
______________________________________ U.S. Pat. No. Inventor Date ______________________________________ 3,531,805 Winegard et al Sept. 29, 1970 3,475,759 Winegard Oct. 28, 1969 3,329,960 Winegard July 4, 1967 3,007,167 Winegard Oct. 31, 1961 2,992,430 Winegard July 11, 1961 3,321,764 Winegard et al May 23, 1967 ______________________________________
One such prior art approach is conventionally available from the WINEGARD COMPANY known as the CHROMSTAR VHF-UHF line of antennas. The largest of this series is the Model CH-8200 (U.S. Pat. No. 2,992,430) comprising a total of 43 elements (29 UHF elements and 22 VHF elements) having a boom length of 173 inches, a turning radius of 98 inches, and a maximum width of 108 inches. The smallest UHF-VHF antenna in the CHROMSTAR series is the Model CH-7074 having a total of seven elements (4 VHF and 3 UHF) with a boom length of 341/2 inches, a turning radius of 56 inches, and a maximum width of 108 inches.
In the conventionally available GOLD STAR line from the WINEGARD COMPANY, the VHF portion of the antennas are substantially "V" types and the smallest UHF-VHF antenna in this series has a total of ten elements (3 VHF and 7 UHF) with a boom length of 263/4 inches, a turning radius of 481/2 inches, and a maximum width of 89 inches.
Another series of conventionally available "multi-element" large antennas available from the WINEGARD COMPANY are called PREMIER "X" and these antennas intermix both VHF and UHF signals on the same linear plane. The smallest UHF-VHF antenna in this series has five elements (Model X-15).
The second general category of consumer VHF-UHF television antennas may properly be termed "rabbit-ears." The WINEGARD COMPANY also manufactures a conventional series of VHF-UHF indoor antennas known as the COLOR CEPTOR line and the POWERBEAM line. All of these prior art approaches are designed to have a base member which preferably sets on the top of a television set with at least two upstanding adjustable antenna elements affixed thereto. In addition, a UHF upstanding circular element may also be provided. Rabbit ear antennas, however, are not known for significant response.
A consumer antenna nearing (or approaching) the performance of the large multi-element antennas, yet combining the size and lightweight of the small rabbit-ears antennas would form a third classification of consumer VHF-UHF television antennas. The SENSAR line conventionally available from WINEGARD COMPANY (Models Sr-20A, SR-30M, and RVH-2K) properly falls in this category.
The Radio Corporation of America (RCA) also manufactures an antenna in this third consumer category which is identified as Model 5MS550 and termed the AC-DC MINISTATE ANTENNA SYSTEM. The RCA system contains a miniaturized uni-directional antenna, a solid state amplifier and an electrical rotating mechanism all housed inside a weather-proof housing. The diameter of the housing of the RCA system is 201/2 inches. The VHF section of the RCA system is a circular shaped, slot tune, broad band, uni-directional traveling wave antenna. The UHF section, on the other hand, is a broad band multi-element array. The VHF signal must be amplified and then is combined with an unamplified UHF signal by means of an adder circuit.
The present invention more properly falls in the third category of consumer antennas. The antenna system of the present invention performs like a large multi-element antenna twice its size yet maintains the compactness and lightweightness of the rabbit-ear consumer category. Like the RCA antenna system, the antenna system of the present invention utilizes a unique weather-tight housing and can optionally contain a rotor for rotating the antenna, and a preamplifier circuit. Unlike the RCA system, the preamplifier is not necessary for operation of the antenna. The rotor is protected against dirt and weather for long life and enables the antenna to rotate substantially 360.degree.. More importantly, and in contrast to the RCA system, the antenna system of the present invention utilizes outwardly extending antenna elements for the entire VHF-UHF band. Unlike the large television antennas of the first category, the antenna system of the present invention utilizes no horizontal cross-arms or booms, as conventionally termed, and hence does not require conventional saddle supports of insulating materials or the like. However, since the antenna of the present invention does utilize outwardly extending antenna elements, these elements are positively locked to substantially minimize sagging, and/or misaligning due to windloading, icing, and the like.
Most fundamentally, the antenna system of the present invention contains six outwardly extending antenna halves forming three elements, each having the same physical length. No prior art all band VHF-UHF television antenna utilizes such an element configuration. From a manufacturing and cost viewpoint, the antenna system of the present invention represents a major breakthrough. Only one size of element need be manufactured and stocked.
The six element halves are combined into three elements wherein the first and second elements are utilized primarily to receive a VHF signal in the low band and wherein the second and third elements are utilized primarily to receive signals in the high VHF band. The physical spacing between each element is substantially the same and is substantially less than one-tenth of a wave length of the shortest VHF wave length.
The VHF frequency range includes a low VHF band of 54 mHz to 88 mHz (channels 2-6) and a high VHF band of 174 mHz to 216 mHz (channels 7-13). Hence the shortest wavelength in the VHF range occurs at 216 mHz with 54.3"--the one-tenth wavelength being 5.43". Conventionally the spacings between the VHF antenna elements may be a quarter wavelength (i.e., 13.6") and the element halves are interconnected in a crossover fashion (front fed) so that the combined signals are in phase to be additive. As set forth in U.S. Pat. No. 3,392,399 (issued to WINEGARD on July 9, 1968) the spacings between the driven VHF dipoles can be reduced to minimum spacing of approximately one-tenth of a wavelength with reference to the high end of the high VHF band. Hence, spacings of 5.75 inches were achieved by using a transmission line having a series of serpentine or sinusoidal convolutions formed in a plane parallel to the plane of the dipole elements. The antenna of the present invention achieves a spacing between the driven elements substantially less than one-tenth of a wavelength with respect to the same reference. Again, the high degree of compactness of the antenna system of the present invention is due in part to the close physical spacing between the elements as taught in the present invention. This contributes significantly to the overall compactness of the antenna and the lightweightness of the antenna. Significant breakthroughs in manufacturing costs are also obtained.
As a result, the all band UHF-VHF antenna system of the present invention, in a preferable embodiment, has a turning radius of just under 30 inches, a housing longitudinal length of approximately 8 inches, utilization of six identical silver anodized antenna element halves (three elements), a physical weight in the shipping carton of less than two pounds, and a weatherproof housing which may optionally contain a rotor and preamplifier.


A micro-optics assembly and a method for assembling the micro-optics assembly are provided. The micro-optics assembly may include an optical bench having an opening, a cylindrical body disposed in the opening and having a solder well, a heating element thermally coupled to the solder well, and an optical element. The optical element may include a frame having a post and a micro-optic mounted in the frame. The post may be secured in a solid solder material disposed within the solder well in the cylindrical body. The solder may be reflowable such that the micro-optics assembly is reconfigurable without the need for optical realignment components permanently mounted to the optical bench.

The description provided in the background section, including without limitation, any problems, features, solutions or information, should not be assumed to be prior art merely because it is mentioned in or associated with the background section. The background section may include information that describes one or more aspects of the subject technology.
Photonic integrated circuits formed in semiconductor substrates are sometimes used to modify or process optical signals. However, in various applications, such as applications in which mixed materials are used or high optical power is desired, photonic integrated circuits cannot be used and micro-optic systems with micro-optics mounted to an optical bench are sometimes used.
However, conventional micro-optic systems with micro-optics mounted to an optical bench are limited in that fine-pitch tip/tilt optic adjusters and associated fine-pitch adjustment screws must be included in the assembly to align each micro-optic and then must remain on the optical bench to constrain the desired position of the optics for the life of the assembly. The fine-pitch tip/tilt optic adjusters and associated fine-pitch adjustment screws can be bulky, particularly in comparison to the size of the micro-optic, and therefore limit the fill factor of the micro-optic system, add undesirable weight and size to the micro-optic system, and typically limit the size of the micro-optics to greater than twelve millimeters in diameter.

Systems and methods for reconfigurable micro-optic assemblies

Lockheed Martin Coherent Technologies, Inc.


Methods and systems to reduce or eliminate numerical oscillations in solutions that occur when using conventional MPFA when modeling flow in a reservoir are provided. The technique may be referred to as enriched multi-point flux approximation (EMPFA) and may be used to improve the consistency and accuracy in constructing pressure interpolations in cells for the purpose of determining flux equations used in predicting flow in a reservoir.

1. Field of the Invention
The present invention generally relates to the modeling of hydrocarbon reservoirs and particularly to providing a more consistent and accurate representation of fluid flows and pressure gradients.
2. Description of the Related Art
Locating petroleum deposits, drilling wells and managing the extraction of petroleum from a deposit is done at great expense. Due to the complicated and critical nature of locating and managing hydrocarbon deposits, new professions have evolved and special technologies have been developed in order to reduce uncertainty, lower costs, and optimize production. Petroleum engineers, production engineers, geophysicists and geologists now use computerized models of the earth's crust to plan exploration and manage production of petroleum reservoirs.
Reservoir conditions are not static and gas and liquids in a reservoir can move rapidly. Engineers use numerical simulations in modeling the movements of gas and liquid in hydrocarbon reservoirs. These simulations aid engineers in gaining a better understanding of a reservoir's structure and flow properties, as well as aiding in developing an optimal production strategy which maximizes recovery and achieves the best economic result. Modern reservoir modeling has rapidly grown in complexity and can involve the integration of numerous software packages and computational engines. However, a modeling task can generally be broken down into five major steps: geological modeling, gridding and property generation, initialization, history matching and prediction.
Geological modeling concerns establishing reservoir geometry, reservoir boundaries and faults, as well as establishing basic rock properties such as porosity and permeability distributions. In order to provide an accurate representation of a reservoir, data can be incorporated from a very large number of sources including physical surveys, seismographic surveys, and data from wells. Engineers often have very detailed data about the characteristics and properties of specific and discrete locations within the reservoir. During initialization, this data may be used to determine the total amount of fluids as well as fluid compositions and phase saturations in discrete cells. History matching may be performed after running a simulation by comparing numerical results (e.g., for well production rate, gas oil ratio, water-cut, etc.) against actual field data and adjustments may be made to the reservoir model to reduce discrepancies. Once a model is refined, it may be used to predict future well production rates and a well management strategy based on the simulated reservoir flow conditions may be designed that aims to optimize overall recovery or economic results.
Gridding is typically performed to discretize a reservoir into a finite number of cells in order to simulate the behavior of the reservoir. It is often the case that grid orientation, grid size and grid geometry has a large impact on the accuracy of a simulation. In general, to resolve pressure, saturation, or permeability variation across the reservoir, smaller grid cells need to be used where such variation is large. For example, cell sizes in the surroundings of a well may need to be small because of the usually large pressure drawdown at those locations.
Besides grid sizes, grid orientation and grid geometry may also have a strong impact on simulation results. To reduce grid orientation effect, for example, grids may be aligned along major reservoir geological features, such as facies or faults, as well as streamlines for fluid flows. With commonly used Cartesian grid using local refinements, it may be possible to generate grids with cells of varying sizes, but it may be difficult to align cells along geological features or flow streamlines. For isotropic permeability distributions and features that are horizontal or vertical, this grid orientation problem with Cartesian grid may be partially solved with the advent of a K-orthogonal grids where gridnodes can be distributed more or less freely in space to conform to reservoir geometry. For anisotropic and highly heterogeneous permeability fields, it is almost impossible to create K-orthogonal grids. Therefore, conventional two point flux approximation (TPFA), which computes the flux of a face between two adjacent gridblocks by piecewise linearly interpolating the grid cell pressures, may no longer be accurate or valid and multi-point flux approximation (MPFA) should be used. MPFA involves a larger stencil to calculate the flux and is recognized by researchers as a way to improve numerical accuracy.
With MPFA, formulas for calculating fluxes are first derived for single phase flows, and then generalized to multiphase phase flows by accounting for saturation effects on relative permeability. The goal in the derivation is to solve for a pressure gradient field in the reservoir which yields fluxes that are consistent across interfaces between grid cells. To compute the pressure gradient in 2D, interaction regions are constructed around each vertex of the grid by joining the center of each grid cell sharing the vertex with centers of the cell edges that meet at the vertex. In 3D, interaction regions are created by constructing surfaces that are bounded by lines connecting block centers and face centers and lines connecting face centers and edge centers of cells around the vertex.
Computing a pressure gradient using MPFA may be described with reference to FIG. 1, which shows an exemplary set of adjacent grid cells 1101-1104 sharing a common vertex O. An interaction region 120 is constructed by joining cell centers C1-C4 with centers M1-M4 of cell edges that meet at the vertex O. To facilitate discussion, each portion of an interaction region that is contained in one of the cells is referred to as a subvolume. For example, in FIG. 1, quadrilaterals C2M1OM2, C3M2OM3, C4M3OM4 and C1M4OM1 are the four subvolumes of the interaction region 120.
With conventional MPFA, the pressure gradient is assumed constant in each subvolume and is obtained by using first order Taylor expansion or linear interpolation based on the pressure value at the cell center (Ci, i=1 to 4) and those at the edge centers (Mi, i=1 to 4) of the same subvolume. Using the pressure gradient and Darcy's law,F=nTλK∇p  (1)fluxes may then be written in terms of the pci and pek, where F is flux in feet per day, n is the normal vector, λ is the fluid mobility in 1/cp, K is a permeability tensor in millidarcys, ∇ is the gradient operator in 1/ft and p is pressure in pounds per square inch. Though not written explicitly, a unit conversion factor of 0.00633 may be used on the right hand side to convert md-psi/ft-cp to ft/day. By balancing fluxes across each half-edge inside the interaction region (M1M2, M2M3, M3M4, and M4M1), a formula for pressure at any point pek may be derived as linear functions of pci. Upon substitution, these equations may yield expressions for fluxes as linear functions of all pressure values at grid cell centers. The exact forms of these linear relationships may depend on the selected cell geometry and permeability tensors on grid cells surrounding the subvolume. In reservoir simulation, pressures at block centers may then be solved to determine the flows and state of the system.
In general, with MPFA the increase in computational cost when compared to TPFA is relatively small but results are shown to be more accurate, as expected. However, it has been observed that MPFA could result in severe unphysical oscillations in numerical solutions for single phase pressure equation−∇·K∇p=g  (2)if the permeability field is strongly anisotropic, where g is a source/sink term and a constant mobility of 1 is assumed to simplify the notations. These numerical oscillations may be linked to the lack of monotonicity in the solution matrix for the discretization problem and efforts have been made to improve MPFA so that matrix monotonicity can be restored. In any case, the possible occurrence of these oscillations may pose a severe limitation to the use of MPFA in many applications.
Accordingly, what is needed is an improved method for approximating flux gradients.


To achieve a reduction in the size of the print head and a reduction in the cost, LED array chips 1 achieved by matrix-connecting M.times.N LED elements 2 with M pad electrodes to be scanned 4 and N pad electrodes to be driven 3 and LED array drive ICs 10 are mounted at a mounting substrate 41. The pad electrodes to be driven 3 are connected with drive pad electrodes 16 and the pad electrodes to be scanned 4 are connected with scan pad electrodes 17 through wires 42a and 42b respectively. The pad electrodes to be driven 3 and the pad electrodes to be scanned 4 are provided in a single row along one side or edge of the lengthwise side of the chip. The LED array drive ICs 10 are provided with a scan control unit that sequentially validates the M pad electrodes to be scanned 4 one at a time based upon a scan signal and a data control unit that supplies drive currents to the N pad electrodes to be driven 3 in conformance to individual sets of data to cause N LED elements 2 connected with a valid pad electrode to be scanned 4 to emit light, each time the valid pad electrode to be scanned 4 is switched.

The present invention relates to a print head that is employed as a exposure light source for forming an electrostatic latent image on a photosensitive body in a printing apparatuses such as printers and facsimile machines adopting the electrophotographic printing system, and the present invention also relates to a matrix-type light emitting element array chip to constitute the print head and a light emitting element array drive IC that drives the matrix-type light emitting element array chip.
Print heads that are employed as an exposure light source for a photosensitive body in a printing apparatus adopting the electrophotographic printing system in the prior art include those that use as a light source, a light emitting element array constituted by providing a number of light emitting elements such as semiconductor laser elements, LED elements and the like in a single row, and those that use a fluorescent light, a cold-cathode tube or the like as a light source and use a liquid crystal element as a shutter. Those different types of print heads all selectively expose the photosensitive body that has been uniformly charged by a charger with the light source to form an electrostatic latent image on the photosensitive body.
In this document, a light emitting element array achieved by providing a great number of LED elements is referred to as an LED array, and a print head constituted with an LED array is referred to as an LED print head. An LED print head may be constituted by mounting on a mounting substrate LED array chips each achieved by providing a great number of LED elements on a single semiconductor chip and light emitting element array drive ICs each provided for controlling light emission of the individual LED elements in each of the LED array chips, in quantities that correspond to the printing width.
FIG. 8 is a top view illustrating the structure of an LED array chip in the prior art. The LED array chip 51 illustrated in FIG. 8 is provided with LED elements 52 provided in a single row, individual pad electrodes to be driven 53 that are individually connected to the anodes of the LED elements 52 and a common electrode 54 that is connected to the cathodes of all the LED elements 52. The common electrode 54 is provided at the rear surface of the LED array chip 51. In addition, FIG. 9 is a partial enlargement of an LED print head in the prior art mounted with the LED array chip illustrated in FIG. 8. The LED print pad illustrated in FIG. 9 is constituted by mounting the LED array chip 51 and an LED array drive IC 55 for driving the LED array chip 51 at a mounting substrate 59. The individual pad electrodes to be driven 53 of the LED array chip 51 and drive pad electrodes 60 of the LED array drive IC 55 are connected with each other through metal wires 56, and I/O pad electrodes 61 of the LED array drive IC 55 are connected with wiring patterns (conductive patterns) 62 for control signals and the source formed at the mounting substrate 59. The common electrode 54 formed at the rear surface of the LED array chip 51 is connected to a cathode wiring pattern (conductive pattern) 58 formed at the mounting substrate 59.
Individual sets of data corresponding to the LED elements 52 at the LED array chip 51, a strobe signal for controlling the light emission time for the LED elements and the like are input through the LED array drive IC 55. The LED array drive IC 55 is provided with a shift register that stores individual sets of data that have been input, drive current source circuits each of which outputs a drive current corresponding to one of the individual sets of data and switching circuits that turn ON/OFF between the output terminals of the drive source circuit and the drive pad electrodes 60 in conformance with the strobe signal that has been input. The number of shift register stages, the number of drive current source circuits, the number of switching circuits and the number of drive pad electrodes 60 all correspond to the number of LED elements 52 at the LED array chip 51. In the LED array drive IC 55, a drive current is output by, for instance, the drive current source circuit corresponding to the printing data that indicate light emission, and with the switching circuits set to ON while the strobe signal is at "H" level, the drive current is supplied to the LED elements 52 that correspond to the printing data at "L" level via the individual pad electrodes 53 to be driven to achieve selective light emission. Thus, in the LED print head of the prior art, the anodes of the LED elements 52 at the LED array chip 51 are connected to the individual pad electrodes 53 to be driven (the drive pad electrodes 60 at the drive IC 55) on a one-to-one basis.
However, as the high density of the LED elements at an LED array chip increases (achieving a dot density of 600 DPI and an LED element pitch of 42.3 micrometer, for instance), it becomes increasingly difficult to individually connect the individual pad electrodes to be driven 53 and the drive pad electrodes 60 that are provided in correspondence to LED elements 52 on a one-to-one basis through wire bonding. A matrix-type LED array chip, such as that disclosed in Japanese Unexamined Patent Publication No. 1987-152873 provides a solution to this problem.
In a matrix-type LED array chip, matrix-connections are achieved between M.times.N light emitting elements and M pad electrodes to be scanned connected to the cathodes of the light emitting elements and between the light emitting elements and N pad electrodes to be driven connected to the anodes of the light emitting elements, in order to reduce the number of pad electrodes in the LED array chip. A matrix-type LED array chip may assume a structure, for instance, in which, a semiconductor chip is divided into M semiconductor blocks, a pad electrode to be scanned and N light emitting elements are formed on each semiconductor block and N pad electrodes to be driven are formed on the M semiconductor blocks, with the cathodes of the N LED elements within each block connected with the pad electrode to be scanned within the block and the anodes of the N LED elements within the block individually connected with different pad electrodes to be driven.
However, in a print head employing the matrix-type light emitting element array chip in the prior art described above, it is necessary to mount two types of drive circuits (drive ICs), i.e., a data control circuit (data control IC) that controls the pad electrodes to be driven in correspondence to individual sets of data and a scan control circuit (scan control IC) for scanning the pad electrodes to be scanned at a mounting substrate and to bond between the pad electrodes to be driven and the data control circuit and between the pad electrodes to be scanned and the data control circuit with metal wires, and this poses an obstacle in achieving a reduction in the size of the print head. It also presents a stumbling block in achieving a reduction in the number of manufacturing steps for manufacturing the print head and a reduction in the manufacturing cost. Since, for instance, a structure in which a light emitting element array chip constituted by providing the pad electrodes to be driven and the pad electrodes to be scanned on either side of the row of light emitting elements is used, a data control circuit and a scan control circuit are mounted at the sides of the light emitting element array chip and the metal wires are drawn out from the two sides of the light emitting element array chip, must be adopted, the size of the print head cannot be reduced and the number of wire bonding steps cannot be reduced either.

Light emitting element array chip, light emitting element array drive IC and print head


The invention is directed to a composite nonwoven fabric comprising a nonwoven web of spunbonded substantially continuous thermoplastic filaments, a nonwoven web of thermoplastic strands, and a nonwoven web of thermoplastic meltblown microfibers sandwiched between the nonwoven web of spunbonded substantially continuous filaments and the nonwoven web of thermoplastic strands. An adhesive agent is disposed between the nonwoven web of spunbonded filaments and the nonwoven web of meltblown microfibers and between the nonwoven web of thermoplastic strands and the nonwoven web of meltblown microfibers, adhering the respective nonwoven webs together to form a unitary composite nonwoven fabric. In a preferred embodiment, the composite nonwoven fabric of the invention comprises a nonwoven web of spunbonded substantially continuous polyamide filaments, a nonwoven web of polyamide strands, and a nonwoven web of polyethylene meltblown microfibers sandwiched between the nonwoven web of spunbonded substantially continuous filaments and the nonwoven web of strands.

Nonwoven barrier fabrics have been developed which impede the passage of bacteria and other contaminants and which are used for disposable medical fabrics, such as surgical drapes, disposable gowns and the like. For example, such barrier fabrics can be formed by sandwiching an inner fibrous web of thermoplastic meltblown microfibers between two outer nonwoven webs of substantially continuous thermoplastic spunbonded filaments. The fibrous meltblown web provides a barrier impervious to bacteria or other contaminants in the composite nonwoven fabric. Such composite fabric structures are known generally in the art as spunbond-meltblown-spunbond, or "SMS," fabrics. Examples of such fabrics are described in U.S. Pat. No. 4,041,203 and U.S. Pat. No. 4,863,785.
In the manufacture of this type of fabric, the respective nonwoven layers are thermally bonded together to form a unitary composite fabric. Typically, the thermal bonding involves passing the nonwoven layers through a heated patterned calender and partially melting the inner meltblown layer in discrete areas to form fusion bonds which hold the nonwoven layers of the composite together. Without sufficient melting and fusion of the meltblown layer, the composite fabric will have poor inter-ply adhesion. However, unless the thermal bonding conditions are accurately controlled, the possibility exists that the thermal bond areas may be heating excessively, causing "pinholes" which can compromise or destroy the barrier properties of the inner meltblown layer. Thus in practice, the thermal bonding conditions which are used represent a compromise between the required inter-ply adhesion strength on the one hand, and the required barrier properties which must be provided by the meltblown layer on the other.
The conventional SMS type barrier fabrics also have limitations in the types of sterilization procedures which can be used. For some applications, it is desired that the fabric or garment be sterilized in the final stages of manufacture by exposure to gamma radiation. For example, the fabric or garment may first be sealed in a protective package, and then exposed to gamma radiation to sterilize the package and its contents. However, sterilization by gamma irradiation has been found to be unsuitable for many of the known medical barrier fabrics. Some of the polymers conventionally used in such medical barrier fabrics, such as conventional grades of polypropylene for example, are especially sensitive to degradation by gamma irradiation. Fabrics produced from such polymers tend to lose strength over time, becoming brittle as a result of the gamma irradiation. Also, the instability of the polymers to the irradiation results in the generation of distasteful odors in the product which are unacceptable to the consumer.
Various attempts have been made to overcome these limitations. For example, efforts have been made to render the polypropylene polymers more stable to gamma irradiation, such as by incorporating certain additives in the polymer to reduce the amount of degradation. For example, U.S. Pat. No. 4,822,666 describes a radiation stabilized polypropylene fabric in which a long-chain aliphatic ester is added to the polymer. U.S. Pat. No. 5,041,483 discloses incorporating a rosin ester into the polypropylene to stabilize the polymer and reduce the tendency toward odor generation after gamma irradiation. However, the use of such additives adds expense to the manufacturing process. Further, polypropylene is difficult to render gamma-stable even with the use of additives or stabilizers.
It would therefore be advantageous to provide a fabric that provides a barrier to the transmission of contaminants and which retains its strength and does not create an unpleasant odor when sterilized in the presence of gamma radiation.

Gamma structure composite nonwoven fabric comprising at least two nonwoven webs adhesively bonded by a lightweight adhesive web


A system for sending and responding to information requests in a wireless communications network includes a display device, a central processing unit, memory means including random access memory and read-only memory, an input device, and a transmitter/receiver. The random access memory further comprises routines for processing, sending and receiving messages over the wireless network.. The present invention also comprises a method for requesting information and a method for responding to requests for information. The preferred method for handling information requests comprises the steps of: monitoring the communications channel for availability; sending an information request over the channel; receiving the information request at each node within the network; preparing responses to the information request at each node; and sending the response to the information request over the channel if it is available. The method for responding to a request for information advantageously uses the minimum number of request to solicit the minimum number of replies to the information request.

1. Field of the Invention
The present invention relates generally to communication systems for computer networks. In particular, the present invention relates to a system and method for sending and responding to information requests in a wireless communications network. Still more particularly, the present invention relates to a non-persistent method of transmitting and receiving data.
2. Description of the Related Art
During the recent past, the use of computer communication networks has become widespread. Included in the development of computer communication networks is the advent of the wireless communication network. Referring now to FIG. 1, a block diagram of a prior art wireless communications system 20 is shown. The wireless communications system 20 comprises a plurality of node computer systems 22 that are positioned within a predetermined distance of each other for sending and receiving messages via radio signals. A particular node, A, can receive signals from any one of the plurality of nodes 22 within a predetermined bounding zone or range as delineated by the circular area 24. Each of the other nodes 22 is also able to receive signals within a range, where each respective node is at the center of the range. The nodes 22 are effectively linked together for communication with each other using a particular channel or frequency for transmitting and receiving signals.
One problem with such wireless networks is that they have only very limited bandwidth. Unlike traditional wire networks, there is no dedicated line coupling the nodes to each other. Because of Federal regulations pertaining to certain frequency bands, the network can only operate a small predetermined amount of time (typically 400 ms) on any one channel, and the signals must be within a narrow frequency band thereby limiting the number of channels available. Thus, the bandwidth for wireless networks to transfer information is severely limited. This significantly impacts the amount of information that can be carried over the network.
Another problem is network flooding. Many network systems provide a class of general broadcast messages or information requests that are sent over the network, and to which any node on the system can respond. Such information requests are sent over the network, and one or more nodes will prepare response messages to provide the information requested. The response messages are then sent over the network back to the requesting node. However, the process of sending a request message often has the effect of flooding the network with multiple redundant response messages responding to the initial request. Unfortunately, these response messages can degrade performance of the network until all the response messages have been delivered to the requesting node. In distributed network systems where multiple nodes may respond, no solution to this network flooding problem has been found. Moreover, the problem of network flooding is even more severe on wireless networks because of their limited bandwidth.
The prior art has attempted to reduce the effects of network flooding using a variety of techniques. One such technique has been to designate a single node as a master node, and to have the master node respond to all messages in the general broadcast class. However, the problem with this method is that the node designated to be master undergoes serious performance degradation because of the added responsibility of having to respond to all the general information requests. The added responsibility creates further problems because it interferes with the normal operation of the master node. Moreover, the nodes in wireless networks are often mobile computers designed for portability. The nodes will continuously move in and out of the range of the wireless network, therefore, it is very difficult to choose a master node and be sure that the master node will always be connected to the network as required for master nodes.
A second technique used to reduce the effects of network flooding has been to designate a group or subset of nodes as masters in an attempt to distribute the costs and burden of responding to the information requests. However, this technique creates other problems. The major shortcoming of the second technique is the difficulty in selecting the appropriate subset of nodes. The appropriate subset of nodes depends on the number of nodes coupled to the network. Since the number of nodes in a wireless network can fluctuate greatly, it is difficult to select the appropriate number of nodes to designate as masters. If the network is small (has very few nodes) and the set of master nodes is large, many duplicate responses will be generated and the reduction of network flooding is minimal. On the other hand, if the network is large (has many nodes) and the set of master nodes is small, any request for information must be generated and sent many times before a response is received. This second technique also requires additional overhead for monitoring the number of master nodes and maintaining the number of master nodes at an appropriate level since a node that is designated a master node may lose contact with the network as it moves outside the range of the network.
Therefore, there is a need for a system and method that effectively eliminate the flooding problems exacerbated by the limited bandwidth of wireless networks. Moreover, there is a need for a system and method that can reduce the effects of flooding even in truly distributed systems on wired networks.

System and method for sending and responding to information requests in a communications network


The present invention relates to a leave-on antimicrobial composition comprising from about 0.001% to about 5.0%, by weight of the leave-on antimicrobial composition, of an antimicrobial active; from about 0.05% to about 10%, by weight of the leave-on antimicrobial composition, of an anionic surfactant; from about 0.1% to about 10%, by weight of the leave-on antimicrobial composition, of a proton donating agent; and from about 0% to about 99.85%, by weight of the leave-on antimicrobial composition, water; wherein the composition is adjusted to a pH of from about 3.0 to about 6.0. The invention also encompasses methods for moisturizing, reducing the number of germs on the skin, and decreasing the spread of transient Gram negative and Gram positive bacteria using the leave-on antimicrobial compositions described herein.

Human health is impacted by many microbial entities. Inoculation by viruses and bacteria cause a wide variety of sicknesses and ailments. Media attention to cases of food poisoning, strep infections, and the like is increasing public awareness of microbial issues.
It is well known that the washing of hard surfaces, food (e.g. fruit or vegetables) and skin, especially the hands, with antimicrobial or non-medicated soap, can remove many viruses and bacteria from the washed surfaces. Removal of the viruses and bacteria is due to the surfactancy of the soap and the mechanical action of the wash procedure. Therefore, it is known and recommended that the people wash frequently to reduce the spread of viruses and bacteria.
Bacteria found on the skin can be divided into two groups: resident and transient bacteria. Resident bacteria are Gram positive bacteria which are established as permanent microcolonies on the surface and outermost layers of the skin and play an important, helpful role in preventing the colonization of other, more harmful bacteria and fungi.
Transient bacteria are bacteria which are not part of the normal resident flora of the skin, but can be deposited when airborne contaminated material lands on the skin or when contaminated material is brought into physical contact with it. Transient bacteria are typically divided into two subclasses: Gram positive and Gram negative. Gram positive bacteria include pathogens such as Staphylococcus aureus, Streptococcus pyogenes and Clostridium botulinum. Gram negative bacteria include pathogens such as Salmonella, Escherichia coli, Klebsiella, Haemophilus, Pseudomonas aeruginosa, Proteus and Shigella dysenteriae. Gram negative bacteria are generally distinguished from Gram positive by an additional protective cell membrane which generally results in the Gram negative bacteria being less susceptible to topical antibacterial actives.
Antimicrobial cleansing products have been marketed in a variety of forms for some time. Forms include deodorant soaps, hard surface cleaners, and surgical disinfectants. These traditional rinse-off antimicrobial products have been formulated to provide bacteria removal during washing. The antimicrobial soaps have also been shown to provide a residual effectiveness against Gram positive bacteria, but limited residual effectiveness versus Gram negative bacteria. By residual effectiveness it is meant that bacteria growth on a surface is controlled for some period of time following the washing/rinsing process. Antimicrobial liquid cleansers are disclosed in U.S. Pat. Nos. 4,847,072, Bissett et al., issued Jul. 11, 1989, 4,939,284, Degenhardt, issued Jul. 3, 1990 and 4,820,698, Degenhardt, issued Apr. 11, 1989, all patents being incorporate herein by reference.
Some of these traditional products, especially the hard surface cleaners and surgical disinfectants, utilize high levels of alcohol and/or harsh surfactants which have been shown to dry out and irritate skin tissues. Ideal personal cleansers should gently cleanse the skin, cause little or no irritation, and not leave the skin overly dry after frequent use and preferably should provide a moisturizing benefit to the skin.
Finally, these traditional antimicrobial compositions have been developed for use in a washing process with water. This limits their use to locations with available water.
Leave-on, topical lotions have been used in the past to moisturize skin. However, these leave-on compositions have not provided antimicrobial protection against transient Gram positive or Gram negative organisms.
PCT application WO 92/18100, Keegan et al., published Oct. 29, 1992 and PCT application WO 95/32705, Fujiwara et al., published Dec. 7, 1995 teach non-wipe liquid skin cleansers comprising mild surfactants, antibacterial agents and acidic compounds to buffer the pH, which provide improved germ hostility. However, the use of the acid compounds for only pH adjustment therein, results in compositions which do not deliver the undissociated acid required to provide improved antimicrobial benefits. This situation is compounded in Keegan and Fujiwara by the preference of mild surfactants, including nonionic surfactants. Neither Keegan nor Fujiwara teach the use of their compositions in a form which can be used without available water, e.g. a leave-on composition. U.S. Pat. No. 3,141,821, issued to Compeau, Jul. 21, 1964 and Irgasan DP 300 (Triclosan.RTM.) technical literature from Ciba-Giegy, Inc., "Basic Formulation for Hand Disinfection 89/42/01" set forth antibacterial skin cleanser compositions which could provide improved antibacterial effectiveness using certain anionic surfactants, antimicrobial actives and acids. However, the selection of highly active surfactants results in personal cleansing compositions which are drying and harsh to the skin. Again, neither reference teaches the use of antimicrobial compositions in a form which can be used without available water, e.g. a leave-on.
Given the severe health impacts of bacteria like Salmonella, Escherichia coli and Shigella, it would be highly desirable to formulate antimicrobial cleansing products which provides improved reduction of these germs on the skin and improved residual effectiveness versus these transient bacteria, which are mild to the skin and which can be used without water. Existing products have been unable to deliver all of these benefits.
Applicants have found that leave-on antimicrobial compositions which provide such mildness and antimicrobial benefits can be formulated by using known antibacterial actives in combination with specific organic and/or inorganic acids as proton donating agents, and specific anionic surfactants, all of which are deposited on the skin. The deposited proton donating agent and anionic surfactant enhance the selected active, to provide a new level of hostility to bacteria contacting the skin.


An improved printing magnet drive device for use in a printing apparatus, such as line printer, is disclosed. The improvement comprises a constant voltage control means in which an output terminal voltage of a transistor is compared with a reference voltage and the comparison result is fed back to the transistor so as to control the output terminal voltage of the transistor to a predetermined value, whereby the voltage applied to the printing magnets is substantially maintained unchanged.

This invention relates to a driving device for printing magnets employed in printing apparatus such as line printers.
In some of such printing magnet drive devices, in order to reduce the number of drive circuits, the printing magnets are divided into a plurality of groups, and the magnets in each group are driven by one drive circuit. Hereinafter, a description will be made with reference to a case where the printing magnets are divided into two groups, that is, a group for odd columns, and a group for even columns, for convenience in description.
Shown in FIG. 1 is one example of a printing magnet drive device in which the printing magnets are divided into a group for odd columns and a group for even columns, and the printing magnets in each group are driven by one drive circuit.
Printing magnets 1 and 2 provided respectively for the odd columns and even columns and adapted to energize printing hammers (not shown) are connected to the terminals of a power source (not shown) through control transistors 3 and 4 reverse-current preventing diodes 5 and switching transistors 6. Furthermore, a series circuit of a diode 7 and a zener diode 8 which form a flyback absorption circuit is connected in parallel to each of the printing magnets 1 and 2. The aforementioned control transistors 3 and 4 are alternately rendered conductive by means of a shuttle switching control circuit 9 with the aid of an inverter 10. In other words, in the odd column printing, the transistor 3 is rendered conductive, while in the even column printing the transistor 4 is rendered conductive.
In the circuit thus organized, the saturation voltages across the collectors and emitters of the control transistors 3 and 4 are varied with the variations of currents flowing therebetween, and therefore the voltages applied to the printing magnets 1 and 2 cannot be maintained unchanged. This is one of the drawbacks accompanying the conventional printing magnet drive device. In other words, when the number of printing magnets 1 and 2 to be driven is changed, the saturation voltages of the transistors 3 and 4 are changed. When the voltages applied to the printing magnets 1 and 2 are changed, the flight time of the printing hammer, that is, the time interval which elapses from the beginning of energization till the hammer strikes a printing type is changed, as a result of which printing quality is lowered.
Furthermore, the number of zener diodes 8 forming flyback absorption circuits connected across the printing magnets 1 and 2 is relatively large, and therefore the conventional printing magnet drive device has problems to be solved with respect to the number of components and in manufacturing cost.


Improved roof cable bolts with reduced protrusion from a mine roof. Particularly, a roof cable bolt head can preferably be dimensioned such that most of its length fits inside a drilled hole in the mine roof.

In the mining arts, roof cable bolts are often employed to strengthen and stabilize a mine roof. Typically, after a cable bolt is installed in a drilled hole, a plate and head protrude from the hole. The top of a protruding head is normally configured for being engaged with a tool that can rotate the cable into the hole and mix resin cartridges, thereby setting the cable fast in the drilled hole.
A problem is commonly encountered in the context of coal seams that are sufficiently small as to result in low heights for mines or tunnels in the seam. Particularly, a problem of low clearances, e.g., for equipment and workers, becomes even worse. Since the head and wedges from a conventional cable bolt can protrude, e.g., 2 or 3 inches (or more) downwardly from the mine roof, a significant hazard is presented to people and equipment in the mine.
Jennmar Corporation, based in Pittsburgh, Pa., has developed a system with the following characteristics:                the use of a collared crater hole;        the use of a dust boot when drilling a collared crater hole using a special tool (see FIG. 4b) to collect dust from the cratering action; and        the use of an inverted dome crater plate with a conventional head.
However, this arrangement involves a level of complexity that adds time and cost to the installation process (as will be more fully appreciated herebelow), including the need for a dedicated process step to form the crater hole.
A need has thus been recognized in connection with realizing bolt installation arrangements and processes that avert such complexity.


There is provided a pressure actuated light comprising a housing means having an open end into which a human digit can be inserted, and a closed end adapted to transmit light; and an illuminating system located proximally to said closed end, comprising a light source, e.g., LED, adjacent said closed end; a battery, e.g., alkaline or NiCd, to provide electrical power to said light source; means for making a permanent electrical connection between said light source and a terminal of said battery; and actuating means comprising a conductor means with one end thereof having a permanent electrical connection to the opposite terminal of said light source, and with the opposite end or intervening portion thereof located proximally to the corresponding opposite terminal of said battery, whereby said conductor means, in cooperation with said inserted human digit and said housing means, is capable of making an intermittent and interruptible electrical connection between said opposite terminal of said light source and said corresponding opposite terminal of said battery. The pressure actuated light is especially useful in the presentation of performances by magicians, where the housing means is preferably a substantially hollow single piece molded from a material so as to closely resemble a human thumb, wherein by applying a slight pressure with the index and second fingers to the tip of the thumb, the illuminating system is activated and the LED emits light, e.g., red, through the thumb. By releasing this slight pressure, the light goes off. Thus, the magician, by simulating a plucking action with his or her hand, will appear to be plucking a light out of thin air, or from any place which the magician desires.

Lighting devices which are actuated by pressure from or contact with some part of the human body have long been used for a variety of purposes. Such applications have included in particular illuminating means for various theatrical displays and performances.
U.S. Pat. No. 993,251 to Howard discloses a support adapted for a human theatrical performance, such as a tight-rope, having sections of electrical contacts so arranged that the movements of the performer will make and break connections between lights placed on the performer's clothing, person or performance apparatus. The sections of electrical contacts comprise wires arranged in alternating sections and extend from opposite sides of a source of electricity. The electrical circuit is completed when the performer, wearing heal and toe contacts mounted on a non-conducting overshoe, bridges the space between any of the alternating sections. The circuit is completed through the source of electricity, and the lights connected to the tips on that particular foot become illuminated.
Another application has been to provide a source of illumination which may be readily attached to and held upon a digit of the human hand in a position to throw light upon any object or objects which it may be desired to see without interfering with the use of the hands and of the thumb and fingers of each hand.
U.S. Pat. No. 914,975 to Radley discloses a portable electric lamp attached to the thumb of the left hand and connected by a flexible conductor cord with a battery slung from the shoulder. Completion of the electrical circuit is by means of a lapped metal ring placed around the user's thumb and secured to the light housing means, and a contact spring attached to and insulated from the light housing means, which extends partially around and underneath the metal ring, terminating in a contact point. When the lapped ring is placed on the user's thumb and the contact spring is pressed against anything held in the hand or against the opposing finger, it is forced into contact with the ring and the circuit is closed between the lamp and battery.
U.S. Pat. No. 5,124,892 to Lambert discloses a night vision illuminating device, especially for use in the cockpit of an aircraft utilizing a night vision imaging system, comprising a self-contained electrical power source located within a small housing means arranged to be releasably secured onto a finger of the pilot. Manually actuatable means comprise switches provided on both sides of the device so that it can be worn on either the right or left hand, with the other hand having access to the switch of the side closest to the other hand. The device is secured onto the finger by means of an elongated fastening tape adhesively secured to the housing means, the outer surface of said fastening tape having a plurality of hook fasteners and the inner surface having a plurality of loop fasteners.
U.S. Pat. No. 4,422,131 to Clanton and Simmons discloses a lighting device in the configuration of a human finger and adapted to be worn as an extension of the human finger. It is activated by forcing the finger into contact with a light source that is supported within the tip of the housing means structure. Particularly, the finger is inserted into the open end of the housing means and is forced into contact with a battery; continued movement of the finger overcomes the force of a spring, causing the battery terminal to come into contact with a bulb contact, completing an electrical circuit, and thereby providing power to the bulb, causing it to glow. Alternatively, the finger is inserted only far enough to contact the battery, and activation of the light is accomplished by placing the closed end of the housing means into contact with a firm surface, against which the finger is then pressed, causing the bulb contact to come into contact with the battery terminal, as in the first alternative.
Still further applications have involved different parts of the human body, with different activating mechanisms and different lighting objectives.
U.S. Pat. No. 5,226,712 to Lucas discloses a hands-free flashlight adapted to be held in a user's mouth, particularly between the upper and lower teeth, so as to direct a beam of light in a desired direction while enabling the use of both hands to perform a particular task. The switch means are structured to be operated between an open and closed position by a biting force exerted by the user's teeth.
U.S. Pat. No. 5,188,447 to Chiang and Ratcliffe discloses an illuminating system comprising an insert attached to the heel of a shoe to provide an illumination every time that the heel of the shoe contacts the ground when the wearer of the shoe is walking, jogging or running, in order that these activities may take place safely under all possible combinations of adverse conditions. A piezoelectric member disposed in the insert produces a signal when the insert is impacted against an object, and this signal is amplified by an amplifier powered by a battery.
U.S. Pat. No. 5,381,615 to MacMillan discloses footwear incorporating a lighting circuit including a pair of pressure responsive switches for controlling the supply of power to the lighting element through a condition responsive logic circuit, whereby the battery life is improved without the necessity for a timing circuit.

Pressure actuated light with digit accommodating housing means


The device is for use with an ammunition storage drum for a modern multi-barrel high rate-of-fire machine gun (i.e., "Gatling" type gun) system, in which unfired ammunition rounds are transported from the drum to the gun, and the cases of the spent ammunition are returned from the gun to the drum. When two generally, oppositely positioned spent ammunition sensors within the drum simultaneously detect spent ammunition in the drum, a signal is sent to the gun control unit in time to cut off power. The device prevents spent ammunition from being chambered in the gun, and as a result also permits higher rates-of-fire by the gun.

This invention relates to a last round detection (i.e., sensing) device and, more particularly, to such a device that is for use with an ammunition storage drum for a modern multi-barrel high rate-of-fire machine gun, such as the 30 mm, Model GAU-8 ("Gatling" type) manufactured and sold by the General Electric Company, Burlington, Vt. 05401.
In ammunition storage devices or reservoirs of the drum type for modern multi-barrel high rate-of-fire machine guns, rounds of ammunition are stored within the ammunition storage drum in abutting positions and around a helical-like core member. As the core member is rotated, the rounds are individually transported to an outlet in the drum. Flexible ammunition chuting is interposed between, and is connected to, the outlet of the ammunition storage drum and the receiver of the gun; and, the chuting is used for handling and transporting the rounds of unfired ammunition from the drum to the gun, and the cases of spent ammunition from the gun back to the drum.
Since the gun fires at a high rate-of-fire, there is the possibility that spent cases which have been returned to the drum will be transported again to the gun and chambered. Obviously, this is undesirable, and to prevent it, prior art "last round" sensing devices, which cut off power to the gun after sensing the last round, have been positioned in the outlet (hereinafter referred to as the "exit" or "exit unit"), FIG. 3, to prevent this occurrence. Although these prior art sensing devices are satisfactory at the present high rates-of-fire, they would not be at higher rates-of-fire, where the length of the flexible ammunition chuting (and the time involved in moving ammunition through this length of chuting) from the exit unit to the gun is very short.
What is needed at contemplated higher rates-of-fire to prevent the chambering of cases of spent ammunition, and is not presently available, is a last round detecting (i.e., sensing) device which will sense the last round a sufficiently long lead time before it reaches the exit unit during the overrun after power cut off.
With our inventive last round detection device we have fulfilled that need; and, thereby, we have significantly advanced the state-of-the-art.

The United States of America as represented by the Secretary of the Air Force


A process for preparing a seam area for a paper machine clothing (PMC) base fabric includes the steps of: forming the PMC base fabric by flat-weaving, the PMC base fabric including warp yarns extending in machine direction and weft yarns extending in cross machine direction and interwoven with the warp yarns, the weft yarns including first weft yarns and a second weft yarn, the second weft yarn being a multifilament yarn, the warp yarns, the first weft yarns, and the multifilament yarn being woven together on a loom in an original weaving process, the multifilament yarn being positioned in an anticipated seam area; and folding over the PMC base fabric, after weaving the multifilament yarn with the warp yarns, to form a seam loop of the PMC base fabric such that the multifilament yarn is a first one of the weft yarns on a sheet side of the seam loop.

1. Field of the Invention
The present invention relates to paper machine clothing, and, more particularly, to a method for preparing a seam area for the clothing in an endless manner.
2. Description of the Related Art
A paper machine clothing (PMC) base fabric is typically manufactured with a specific set of design and quality specifications for a particular paper machine's performance requirements. These specifications include surface characteristics, open area, void volume, permeability and smoothness, among others.
A woven PMC base fabric can be woven "endless". The fabric produced by this method can be referred to as a circular (or round) woven endless fabric. Alternatively, a woven PMC base fabric can be woven "flat", and the free ends can then be joined. The fabric produced by this method can be referred to as a flat-woven fabric.
It is known to manufacture a woven press fabric having a flat-woven base fabric with a plurality of warp yarns forming seam loops along the ends of the fabric extending in a cross machine direction (CD), transverse to the machine direction (MD). The ends are then placed in end-to-end disposition in order to interdigitate the loops and a pintle wire is then inserted in the interdigitated loops to lock the ends together to bring the fabric into an endless form. For installation in a paper machine of the like, the two ends are separated such that the fabric can be pulled in its direction of movement into the machine, after which the two belt longitudinal ends can then be joined together again. The region of the seam in this case has a larger void area than the rest of the fabric, resulting in a differential dewatering in this area which may lead to marking of the fibrous web. In addition, the formation of seam loops on the base fabric results in increased production time and expense.
PCT Intl. App. No. PCT/GB89/00681 discloses a seam for a PMC base fabric in which a number of weft yarns are removed from the fabric at a fold location. The fabric is folded over at the fold location, sewed adjacent the fold location, interdigitated with loops from an adjacent fabric end, and a pintle wire is inserted through the interdigitated loops.
Further, experience has shown that the addition of a multifilament yarn in a seam zone (before the first CD yarn on the sheet side as disclosed in U.S. Pat. No. 5,476,123 (Rydin)) reduces sheet marking and improves seam durability. This method and more recent modifications work on circular woven endless base fabrics. It is thus known to add a multifilament yarn during an original circular weaving process on a loom.
Further, it is known to add a multifilament yarn to the seam after weaving by various methods for flat-woven base fabrics which are then converted into a laminate seam fabric. However, adding the multifilament yarn after weaving is time-consuming.
What is needed in the art is an improved process for preparing a seam area for a PMC base fabric.

Method for preparing a seam area for a PMC base fabric


An auxiliary locking device to be employed in a door knob includes a lock body that has at least two parallel through-bores extending through the body. A first retaining bolt is slidably received in one of the through-bores and includes two ends extending out from the lock body. A second retaining bolt is slidably received in the other one of the through bore and has an end portion extending from the lock body. The end portion of the second bolt has a plate member with an opening around the periphery of which a wall body is mounted. The wall body confines a through-hole that generally has a cross-section equal to and in communication with the opening.

1. Field of Invention
This invention relates to an auxiliary locking device, more particularly to ones which provides additional security and which is to be employed together with a door knob so that the door is double locked and an intruder cannot enter the room even if the door is not locked by the main door knob.
2. Description of the Related Art
Sometimes, people staying in a hotel away from home feel unsafe and uneasy. The reason is simple, we all know that the hotel management possesses an extra key to the hotel room's door by which the door knob can be opened anytime. It might be purely psychological, but some people have difficulty to fall asleep with the knowledge that the room is not wholly secured from intrusion. Certainly, there is usually a chain lock provided at every room's door that includes a chain connected to a clasp and engaged by a link. Unfortunately, the chain lock can be removed once the door is unlocked and opened.

Auxiliary locking device for a door knob


A carrier for small animals includes a removable front wall which serves as a door, as well as a removable bottom wall which serves as a sliding floor. An animal is captured by removing the sliding floor, enclosing the animal from above, and replacing the sliding floor. The sliding floor and door are provided with an interlock to regulate removal and replacement of floor and door.

The present invention relates to carriers for small animals and particularly to a locking system for a carrier having removable front and bottom enclosing panels.
My U.S. Pat. No 5,791,292 discloses a pet carrier in the form of a box-like structure with upstanding side and rear walls, a removable front wall which serves as a sliding door, as well as a removable bottom wall which serves as a sliding floor.
When capturing a small animal, the carrier is first prepared by placing the sliding front door in position on the carrier and removing the sliding floor. The carrier is placed bottom end first over the animal from above and when the animal is within the carrier, the sliding floor is put back into its place. The front door and sliding bottom are preferably latched to each other to secure the animal within the carrier.
The animal may be released by removing either or both the front door and the sliding bottom.
This invention is directed to a locking system for the sliding front wall and sliding floor.