The present invention teaches a real-time hybrid ray tracing method for non-planar specular reflections. The non-planar surface is handled by multiple small planar surfaces. Advantage is taken of the planar nature of triangles that comprise building blocks of a non-planar surface. All secondary rays bouncing from a given surface triangle toward object triangles keep a close direction to each other. A collective control of secondary rays is enabled by this closeness and by decoupling secondary rays from primary rays. The result is high coherence of secondary rays.

Ray tracing is a technique for computing visibility between points. Light transport algorithms simulate the way light-rays propagate through space (while interacting with objects), attaining the resulting colors for the screen pixels. Primary rays are shot from the screen to the scene intersecting with scene objects and generating secondary rays that bounce all over the scene according to the physical laws of optics. (Note: unless specifically stated otherwise, the general term secondary rays used herein throughout the specification discussions, refers to secondary, ternary, and higher degree rays).
Ray tracing is capable of producing a very high degree of visual realism, higher than that of typical raster methods, but at a greater computational cost. Ray tracing is superior to raster graphics by its capability to simulate a wide variety of optical effects, such as glossiness, specularity, radiosity, reflection and refraction, scattering, soft shadows and more. The prior art ray tracing is one of the most computationally complex applications. As such, it is best suited for applications where the image can be rendered slowly ahead of time, such as in still images and film and television visual effects, and is poorly suited for real-time animated application of augmented reality where the real time animation is critical.
Path Tracing.
The traditional ray tracing is not necessarily photorealistic. True photorealism occurs when the rendering equation is closely approximated or fully implemented. Implementing the rendering equation gives true photorealism, as the equation describes every physical effect of light flow. However, this depends on the available computing resources. Path tracing, referred to as a Monte Carlo ray tracing gives far more accurate simulation of real-world lighting. Traditional path tracers [Kajiya, J. T. 1986. The rendering equation. In Proc. SIGGRAPH] shoot rays through each pixel, stochastically scattering according to the profile of the intersected object's reflectance and continuing recursively until striking a light source. Repeated sampling for any given pixel in the image space will eventually cause the average of the samples to converge to the correct solution of a rendering equation, making it one of the most physically accurate 3D graphic rendering methods in existence. Path tracing can generate images that are indistinguishable from photographs. Its visual quality is higher than that of a simple ray tracing, but at a much greater computational cost. (Note: unless specifically stated otherwise, the general term ray tracing, used herein throughout the specification discussions, refers to path tracing.)
A path tracer continuously samples pixels of the screen space. Rays are distributed randomly within each pixel in screen space and at each intersection with an object in the scene a new reflection ray, pointing in a random direction, is generated. After some number of bounces each ray eventually exits the scene or is absorbed.
Path tracing is a global illumination technique. Global illumination takes into account not only the light that comes directly from a light source, but also light reflected by surfaces in the scene, whether specular, diffuse, or semi-reflective. FIG. 1 depicts the sampling of diffuse inter-reflection from the surrounding environment, at a given surface point. In order to achieve global illumination on a diffuse surface, sampling rays must be shot from a hit point (HIP) 10. HIP is a result of a previous encounter between a ray (primary or secondary) and a triangle. The sampling at the HIP is done by shooting many rays, each in a random direction, within the boundaries of a hemisphere 11. The hemisphere is oriented such that its north pole is aligned with the surface normal N.
The relation between the deviation of a sampling ray from the normal N in the hemisphere, and its contribution to the aggregated light energy, is shown in FIG. 2. It is strongly connected with the BRDF (bidirectional reflectance distribution function) of the surface material. BRDF is a function of four real variables that defines how light is reflected at an opaque surface. According to the Monte Carlo technique each of the hemisphere rays is shot from the same HIP but at random direction, bounded by the hemisphere of FIG. 1. As a result, ray's sampled data contributes to the aggregated light energy at the HIP, according to the BRDF function.
Hybrid ray tracing (ray tracing interlaced with raster rendering) is a deferred rendering process based on raster rendering to calculate the primary rays collision, while the secondary rays use a ray tracing approach to obtain shadow, reflection and refraction effects. This approach vastly improves ray tracing performance, not only because many unnecessary traditional ray tracing tasks are avoided, but also because a complete image is available in a demanded time, even if there is not enough time to finish calculations of all the visual effects.
The concept of a hybrid Real-Time Raster and Ray Tracer renderer is not new. Beck et al [Beck et al [Beck, S., c. Bernstein, A., Danch, D., Frohlich, B.: CPU-GPU hybrid real time ray tracing framework (2005)] proposes a CPU-GPU Real-Time Ray-Tracing Framework. Beck proposal spread the traditional stages of ray tracing in independent tasks for the GPU and CPU. These render tasks can be summarized into three GPU render passes: a shadow map generation pass, a geometry identification pass and a blur pass.
Bikker [Bikker, J.: Real-time ray tracing through the eyes of a game developer. In: Proceedings of the 2007 IEEE Symposium on Interactive Ray Tracing, Washington, D.C., USA, IEEE Computer Society (2007)] developed a Real-Time Path Tracer called Brigade, which divides the rendering task seamlessly over both GPU and CPU available cores. Brigade aims the production of proof-of-concept games that use path tracing as the primary rendering algorithm.
Pawel Bak [Bak, P.: Real time ray tracing. Master's thesis, IMM, DTU (2010)] implements a Real-Time Ray Tracer using DirectX 11 and HLSL. Similar to Beck's work, his approach also uses rasterization in order to achieve the best possible performance for primary hits.
Chen [Chen, C. C., Liu, D. S. M.: Use of hardware z-buffered rasterization to accelerate ray tracing. In: Proceedings of the 2007 ACM symposium on Applied computing. SAC '07, New York, N.Y., USA, ACM (2007) 1046-1050] presented a hybrid GPU/CPU ray tracer renderer, where a Zbuffered rasterization is performed to determine the visible triangles at the same time that primary ray intersections are determined. The CPU reads the data back in order to trace secondary rays.
Sabino et al. [Thaler Sabino, Paulo Andrade, Esteban Gonzales Clua, Anselmo Montenegro, Paulo Pagliosa, A Hybrid GPU Rasterized and Ray Traced Rendering Pipeline for Real Time Rendering of Per Pixel Effects, Univ. Federal Fluminense, Rio de Janeiro, Brazil, 2013] present a heuristic approach that select a subset of relevant objects to be ray traced, avoiding traversing rays for objects that might not have a significant contribution to the real time experience.
An important strategy in real-time hybrid ray tracing, is the use of GPU for raster techniques to improve the performance and a smart strategy for prioritizing regions and objects that will receive the ray tracing light effects. NVIDIA's OptiX [Parker, S. G., Bigler, J., Dietrich, A., Friedrich, H., Hoberock, J., Luebke, D., McAllister, D., McGuire, M., Morley, K., Robison, A., Stich, M.: Optix: A general purpose ray tracing engine. ACM Transactions on Graphics (August 2010)] is a general-purpose ray tracing engine targeting both NVIDIA's GPUs and general-purpose hardware in the current version. OptiX architecture offers a low-level ray tracing engine, a programmable ray tracing pipeline with a shader language based on CUDA C/C++, a domain-specific compiler and a scene-graph based representation. OptiX is a GPU only solution with remarkably good results for interactive ray tracing. Recently Nvidia OptiX has got a support by Nvidia RTX, which is a development platform for hybrid ray tracing, for a special purpose hardware. It runs on Nvidia Volta- and Turing-based GPUs, specifically utilizing an architecture for ray tracing acceleration.
Despite all the hybrid ray tracing developments, hybrid real-time ray tracers on low-power devices do not exist in prior art. Their applicability on low-power devices, such as laptops, tablets, hand-held mobiles, becomes more and more relevant. The likelihood of running ray tracing on low power devices is forecasted only to the thirties: "By Moore's law alone by 2032 we could be running real time ray tracing on mobile phones." Jon Peddie, "Peddie predicts we could have real time ray tracing on our PCs in less than 6 years", TechWatch, 27 Mar. 2018.
The hurdles of path tracing that prevent a real-time performance in prior art, either of a full-blown ray tracing or of a hybrid ray tracing are: traversal and frequent reconstruction of accelerating structures, lack of coherence of secondary rays, and a noise causing a "film-grain" appearance of images.
Real-Time Ray Tracing (RTRT).
Historically, ray tracing had been reserved to off-line applications, such as computer-generated photo-realistic animated films. Real-time applications of video games, virtual and augmented reality had have to rely on rasterization for their rendering. RTRT is a hard-computational task, not only because each pixel in the image must be calculated separately, but also because the final color of a single pixel can be affected by more than one recursive ray. Another consideration is that ray tracing algorithms waste from 75% to 95% of its execution time calculating intersection points between rays and objects. RTRT has been enabled by Nvidia's RTX in 2018 (Alwani, Rishi. "Microsoft and Nvidia Tech to Bring Photorealistic Games With Ray Tracing". Gadgets 360. Retrieved Mar. 21, 2018), facilitating a new development in computer graphics of generating interactive images that react to lighting, shadows, reflections by special purpose hardware. Nvidia's RTX is based on traditional ray tracing algorithm accelerated by an on-chip supercomputing hardware of closely 5000 cores. It comprises of a GPU having 4352 cores, AI denoiser utilizing 544 cores, and intersection tests accelerator of 68 cores. The power requirement of a single RTX2080 GPU is 250 W, and the price starts at €418. Due to the high cost and high power of RTX it is targeted at the high-end video games. However, there is a great need to enable real-time ray tracing on consumer class devices (smartphones, tablets, laptops and PC), for video games, VR and AR, democratizing ray tracing to the massive audience which includes limited powered devices. For this end a new and novel method, based on radical algorithmic improvements is needed.
Reflections.
In prior art's hybrid ray tracing the reflections are generated based on G-buffer (Luis Sabino et al., A Hybrid GPU Rasterized and Ray Traced Rendering Pipeline for Real Time Rendering of Per Pixel Effects, 2013). The G-Buffer is generated during the first stage by raster rendering, a "differed shading" stage. The basic idea behind deferred shading is to perform all visibility tests before performing any lighting computations. Therefore, at first, visibility tests are done by raster rendering, while shading is differed to a later stage, combined with ray tracing. The G-buffer produced by the deferred shading stage contains information about optical properties of the underlying material of each pixel. Its contents are used to determine the need for tracing reflection/refraction rays. It is composed by reflectivity, index of refraction, specular exponent and opacity, respectively. The rays need to be traced from the surfaces only through the scene. This way enables to avoid trace of unnecessary rays in places where the material is neither refractive nor reflective. After differed shading is done, the ray tracing algorithm starts with secondary rays and can follow its own path. Any secondary ray generated will be traced against scene in order to produce global illumination effects, such as reflections and refractions. The result of this stage can be understood as the generation of a ray trace effects layer. This effects layer will be blended to the image already generated, in order to improve its visual quality with global illumination effects.
According to the G-buffer method the secondary rays are a natural extension of primary rays. Ray tracing that is carried-on by the chosen secondary rays suffer from the same difficulties of conventional ray tracing: lack of coherence of secondary rays and images with stochastic noise.
Lack of Ray Coherence of Secondary Rays.
Coherence of rays is the key to efficient parallelization of ray tracing. In prior art ray tracing the primary and shadow rays are coherent. This coherence is exploited for efficient parallel processing: traversing, intersecting, and shading by packets of coherent rays. They work well for nearby primary rays, since these rays often traverse similar parts of the accelerating data structure. Using this approach, we can reduce the compute time by using SIMD instructions on multiple rays in parallel, reduce memory bandwidth by requesting data only once per packet, and increase cache utilization at the same time. This works fine for primary rays that originate from the camera. Unfortunately, it is not possible to use ray packets effectively with rays of an advanced order (secondary, ternary, etc.). The primary reason is that advanced order rays bounce in different direction losing coherence. Moreover, in path tracing there is an intentional randomization of rays for diffuse reflections. Reorganizing secondary rays to form bundles with higher coherence ratios, are practiced by the prior art. But this kind of regrouping is a quite expensive operation since it involves a scatter/gather step, which may result in only a slight frame rate improvement when reordering is applied.
Sadegi et al. [Iman Sadeghi, Bin Chen, and Henrik Wann, Coherent Path Tracing, Jensen University of California, San Diego, 2009], developed a technique for improving the coherency of secondary rays. This technique uses the same sequence of random numbers for generating secondary rays for all the pixels in each sample. This improves the efficiency of the packet tracing algorithm but creates structured noise patterns in the image.
Noisy Images.
A path tracer continuously samples pixels of the screen space. The image starts to become recognizable after only a multiple samples per pixel. Rays are distributed randomly within each pixel in screen space and at each intersection with an object in the scene a new reflection ray, pointing in a random direction, is generated. After some number of bounces each ray eventually exits the scene or is absorbed. When a ray has finished bouncing about in the scene a sample value is calculated based on the objects the ray bounced against. The sample value is added to the average for the source pixel. The random components in ray tracing cause the rendered image to appear noisy. The noise decreases over time as more and more samples are calculated. The defining factor for render quality is the number of samples per pixel (SPP). The higher SPP you have in a rendered image the less noise will be noticeable. However, the added quality per sample decreases the more samples you have already (since each sample is just contributing to an average over all samples). The difference in image quality between, for example, 20,000 SSP and 21,000 SSP will not be as noticeable as between 1,000 SSP and 2,000 SSP.
The initial high screen resolution transforms to a low spatial resolution that decreases quickly as the rays are progressing deeper into the space. Due to the low spatial resolution each one of the produced frames is noisy. Only converge of many subsequent frames reduces the final image noise. The image to converge and reduce noise to acceptable levels usually takes around 5000 samples for most path traced images, and many more for pathological cases. Noise is particularly a problem for animations, giving them a normally unwanted "film-grain" quality of random speckling.
Accelerating Structures.
The most time-consuming tasks in ray tracing are intersection tests between millions of rays and millions of polygons. They are partly relieved by use of acceleration structures (AS) which are huge binary trees. Every single ray is traversed across an accelerating structure (e.g. K-trees or BVH trees), seeking polygons for intersection. These traversals become a major time-consuming task—they typically take over 70% of the image generation time. The polygons near to the path of the traversing ray are subject to intersection test.
The AS based on binary trees are basically static. They are constructed in a preprocessing step. Such a step takes typically much more time than rendering an image. The construction time depends on the scene size. Every major modification of the scene necessitates a reconstruction of the static acceleration structures. Moreover, the memory size is typically doubled by these structures.
There are two major drawbacks associated with the use of static acceleration structures; (i) traversals of these structures are time-consuming, challenging the real-time requirements, and (ii) they must be repeatedly reconstructed upon scene changes, which contradicts with real time animation. Reconstructing static acceleration structure is a computationally intensive task, preventing real-time animation.

Specular reflections in hybrid ray tracing


New tumor rejection antigen precursors, and the nucleic acid molecules which code for them, are disclosed. These tumor rejection antigen precursors are referred to as NAG tumor rejection antigen precursors, and the nucleic acid molecules which code for them are referred to as NAG coding molecules. Various diagnostic and therapeutic uses of the coding sequences and the tumor rejection antigen precursor molecules are described.

The process by which the mammalian immune system recognizes and reacts to foreign or alien materials is a complex one. An important facet of the system is the T cell response. This response requires that T cells recognize and interact with complexes of cell surface molecules, referred to as human leukocyte antigens ("HLA"), or major histocompatibility complexes ("MHCs"), and peptides. The peptides are derived from larger molecules which are processed by the cells which also present the HLA/MHC molecule. See Male et al., Advanced Immunology (J.P. Lipincott Company, 1987), especially chapters 6-10. The interaction of T cells and complexes of HLA/peptide is restricted, requiring a T cell specific for a particular combination of an HLA molecule and a peptide. If a specific T cell is not present, there is no T cell response even if its partner complex is present. Similarly, there is no response if the specific complex is absent, but the T cell is present. This mechanism is involved in the immune system's response to foreign materials, in autoimmune pathologies, and in responses to cellular abnormalities. Much work has focused on the mechanisms by which proteins are processed into the HLA binding peptides. See Barinaga, Science, 257: 880 (1992); Fremont et al., Science, 257: 919 (1992); Matsumura et al., Science, 257: 927 (1992); and Latron et al., Science, 257: 964 (1992).
The mechanism by which T cells recognize cellular abnormalities has also been implicated in cancer. For example, in PCT application PCT/US92/04354, filed May 22, 1992, published on Nov. 26, 1992, and incorporated herein by reference, a family of genes is disclosed, which are processed into peptides which, in turn, are expressed on cell surfaces, which can lead to lysis of the tumor cells by specific CTLs. The genes are said to code for "tumor rejection antigen precursors" or "TRAP" molecules, and the peptides derived therefrom are referred to as "tumor rejection antigens" or "TRAs". See Traversari et al., Immunogenetics, 35: 145 (1992); van der Bruggen et al., Science, 254: 1643 (1991), for further information on this family of genes. Also, see U.S. Pat. No. 5,342,774.
In U.S. patent application Ser. No. 938,334, now U.S. Pat. No. 5,405,990 the disclosure of which is incorporated herein by reference, nonapeptides are taught which are presented by the HLA-A1 molecule. The reference teaches that given the known specificity of particular peptides for particular HLA molecules, a particular peptide is expected to bind one HLA molecule, but not others. This is important, because different individuals possess different HLA phenotypes. As a result, while identification of a particular peptide as being a partner for a specific HLA molecule has diagnostic and therapeutic ramifications, these are only relevant for individuals with that particular HLA phenotype. There is a need for further work in the area, because cellular abnormalities are not restricted to one particular HLA phenotype, and targeted therapy requires some knowledge of the phenotype of the abnormal cells at issue.
As described hereinbelow, the present application is directed to new intron-expressed tumor rejection antigens which are presented by MHC molecule HLA-A2, and to nucleic acid molecules encoding said antigens. The present application is further directed to therapeutic and diagnostic methods utilizing the new tumor rejection antigens. The invention is elaborated upon further in the disclosure which follows.

Isolated nucleic acid molecules, peptides which form complexes with MHC molecule HLA-A2 and uses thereof

INSERM (Institute National de la Sante et de la Rechereche Medicale)


Dental post to be fitted, particularly, within a dental cavity (3) comprises axial and longitudinal stiffening elements (7). At least a portion of the stiffening elements which is to be fixed within the cavity (3) comprises, at least at its periphery, a curable product (9) capable of yielding under an applied force so as to conform to the walls of the cavity in which it is located. The product is curable after being introduced into the cavity.

In odontology posts are known to be used in metal or a composite material to reconstruct a root treated tooth.
These posts, of whatever material they are made, have a circular cross-section which means that when they are placed in dental root canals whose cross-section is of a different shape, only a small part of their outer surface comes into contact with the inner wall of the tooth. Mechanical locking of the post is therefore not fully effective, and it is sometimes necessary to improve the lock by inserting various reconstruction or cementing products into the free spaces between the tooth and the post.
If the practitioner wishes to achieve a perfect fit of the post inside an ovoid root canal, a very precise root canal impression has to be made for example in silicon which is forwarded to a prosthesis laboratory to have a so-called anatoform post made of cast metal, which has the disadvantage of being costly and requires three successive procedures which can be a source of imprecision, these being taking an impression of high accuracy, making a wax post in this impression and finally casting the metal post with the risk of over-sizing at the time of casting.
Patent FR-A-2 669 211 proposed filling the spaces between the post and the root canal with an injection of setting resin which also bonds the post to the canal. One disadvantage of this technique is that the extent of shrinkage which takes place in the resin during setting increases with the mass of resin. Under these conditions the shrinkage which occurs in different places within the root canal can be extensive and creates areas in which bonding is not satisfactory.
Document DE-A-3 825 601 also describes a dental post whose upper end is provided with a part of truncated cone shape forming a core of greater diameter intended to reconstruct a deteriorated tooth. This dental post is positioned in the root canal of the tooth and is made up of a synthetic product containing fibres which may be carbon or glass fibres. This type of post is fixed in the root canal of the tooth by bonding or cementing means. Such device has drawbacks similar to those described in the document mentioned previously.
The purpose of the present invention is to remedy such drawbacks. This invention therefore sets out to improve both the ease and quality of applying reinforcements to a dental cavity. One particular purpose of the present invention is to propose a dental reinforcement which is able to fit the contour of the cavity, or root canal, in which it is to be positioned.

Societe de Recherches Techniques Dentaires R.T.D.


To further reduce contact resistance when a current or a voltage is taken out from a metal layer.

In recent years, a two-dimensional material having a two-dimensional crystal structure has attracted attention as a next-generation material. The two-dimensional material has a layered crystal structure in which unit layers each having a two-dimensional structure are laminated, and exhibits a high carrier mobility and the like due to the crystal structure, and thus is expected to be applied to a semiconductor device.
For example, Patent Document 1 below exemplifies, as a two-dimensional material, a carbon-based two-dimensional material such as graphene, or a transition metal dichalcogenide that is a compound of a transition metal and a chalcogenide element.

Conductive structure, method of forming conductive structure, and semiconductor device

Abstract: A conductive structure including: an insulating layer; a metal layer provided on one surface of the insulating layer to protrude in a thickness direction of the insulating layer; and a two-dimensional material layer provided along outer shapes of the metal layer and the insulating layer from a side surface of the metal layer to the one surface of the insulating layer.

SONY SEMICONDUCTOR SOLUTIONS CORPORATION


A truck trailer that can be loaded from the sides or from overhead and which allows cargo to be transported within an enclosure includes a trailer bed, and an enclosure that is linearly movable with respect to the trailer bed from a position in which the enclosure extends over the entire length of the trailer bed to a position in which substantially the entire trailer is uncovered. In certain embodiments, a roller and track mechanism is used for facilitating linear movement of the enclosure as a unit from an enclosing position to an open position.

Truck trailers used for transporting freight include both open and closed bed trailers. Open bed trailers, commonly referred to as flatbed vehicles, offer the advantage of accommodating a variety of loads and are generally less expensive to produce. Further, the load on the trailer can be accessed from the sides and above as well as from the rear of the vehicle. However, these trailers have disadvantages in that the load is open to the environment and can be damaged in transit or readily pilfered. Further, it is not particle to transport certain types of cargo on an open bed trailer, especially during inclement weather.
Closed trailers have the advantage of providing superior protection and security for the load. However, the presence of a conventional enclosure with a fixed height roof limits access to the load, makes loading of the trailer more difficult, and results in less useable space for the same size trailer bed width and limits the use of forklifts to load the trailer as the trailer roof interferes with the ability of the forklift operator to adequately lift the load. Further, the mere presence of the walls and roof of the enclosure limits the ability to utilize the full internal width and height of the enclosed trailer without hand stacking.
In addition, in order to accommodate all types of freight, a carrier must maintain an inventory of both open and closed trailers. Inventory requirements could be reduced by a truck trailer that can be easily loaded from the sides or from overhead, as with a conventional flatbed trailer, yet have an enclosure that provides added protection and security for the load.
Open trailers are typically utilized for transporting crushed vehicle bodies, since there is not any practical method for quickly and easily loading a crushed vehicle body onto a covered trailer. However, new Federal laws require that crushed autobodies transported on a trailer are covered to prevent any loose debris from falling from the trailer onto the roadway. Conventional methods of covering crushed automobiles (or other cargo) involve placing a tarp over the cargo. This is often very difficult and may subject operators to injury due to falls while placing the tarp.
U.S. Pat. No. 6,017,082 describes a truck trailer body system with movable enclosure sections, which are preferably slidingly nestable canopies. The canopies are positionable for completely enclosing and protecting cargo from environmental damage during transportation or storage, and also for selectively providing unfettered access to areas of the trailer bed for loading and unloading.
U.S. Pat. No. 6,196,604 describes a removable enclosure for a flatbed vehicle. The enclosure comprises a panel roof supported by four upright supports for removably mounting on an open bed trailer. Two upright supports are located on the left and right corners (the driver side and passenger side) of the forward edge of the trailer, and the other two uprights are located at the rear corners of the trailer. Two movable and removable side supports typically are used with the disclosed enclosure. Elevating means within the upright supports allow the front and/or rear portions of the roof to be raised and lowered separately. Using external attachable fixtures and ground mounted supports, each of the roof supports can be lifted from their mounted position on the trailer bed and the trailer can be driven out from under the supports and roof assembly, converting a covered van to a fully open van. A tarpaulin, or other readily removable wall materials, can be suspended from the roof and attached to the trailer bed.
U.S. Pat. No. 6,196,786 discloses a cargo transporting vehicle having a flap unit mounted as a cargo containing unit on a flatbed trailer so that it can be freely moved along the longitudinal direction of the truck. The flap unit comprises pillars that form the framework for the cargo containing unit. Each of the pillars includes an upper wheel and a lower wheel that sandwich a flange of an I-beam member. This arrangement allows the pillars to be moved along the length of the trailer to cover or uncover the trailer bed. Side panels which form the sidewalls of the trailer cover, and roof panels are hinged to the pillars so that they can be folded or swung into a position that allows the pillars to be rolled forward toward the front of the trailer to uncover the flatbed.
Other patent publications that address similar issues include U.S. Pat. Nos. 5,282,663; 3,266,837; 3,252,730; 3,155,419; 2,974,996 and 2,866,663.


An x-ray source of the type used in medical or inspection devices having a first and second housing part which are detachably secured together to define an interior chamber for the housing. A plurality of power feeds is secured to the first housing part wherein each power feed has an elongated conductor extending into the chamber such that the conductors are parallel to each other. A removable cathode assembly includes a mounting plate having a plurality of tubular standoffs constructed of an electrically insulating material. These standoffs, furthermore, are secured to the mounting plate and protrude outwardly therefrom so that one standoff is associated with and registers with the conductor for each power feed. With the cathode assembly mounted in the housing chamber, the cathode assembly is secured to the housing by a threaded member extending through a cap secured to each standoff such that one end of the threaded member frictionally engages the conductor in its associated standoff thus securing the cathode assembly to the housing.

I. Field of the Invention
The present invention relates generally to x-ray sources and, more particularly, to such an x-ray source with a removable cathode assembly.
II. Description of the Prior Art
There are many different types of x-ray sources utilized in medical and inspection devices. These x-ray sources all comprise a housing having an interior chamber which is maintained in a near absolute vacuum.
A cathode assembly is fixedly mounted within the chamber which, upon activation, generates free electrons. These free electrons are then accelerated toward an anode contained in the housing so that, once the electrons strike the anode, x-rays are generated. The generated x-rays then pass out through a window substantially transparent to x-rays and exteriorly of the housing.
One disadvantage of these previously known x-ray sources is that the cathodes, by their very nature, become depleted after extended use. Once the cathode has been depleted, the entire x-ray source is discarded and replaced with a new x-ray source.
A still further disadvantage of these prior art devices is that different cathode designs are required for different applications. This has previously required the use of entire different x-ray sources for different applications.
This previously known practice of discarding the x-ray source after depletion of the cathode as well as the use of different x-ray sources for different types of applications, however, is extremely wasteful. In particular, many components of the x-ray source, e.g. the housing, anode and associated components, all exhibit useful lives greatly in excess of the cathode assembly. These other components are also costly.

X-ray source having removable cathode assembly


The present invention relates to a novel polypeptide that binds selectively to mouse or rabbit immunoglobulin G. More specifically, the present invention relates to a polypeptide that binds to mouse or rabbit immunoglobulin G, a polynucleotide encoding the polypeptide, an expression vector comprising the polynucleotide, a transformant introduced with the expression vector, a method of producing the polypeptide using the transformant, and a composition for immunoassay comprising the polypeptide. The novel peptide according to the present invention binds specifically to mouse or rabbit immunoglobulin G, can replace conventional expensive secondary immunoglobulin G, and can be used in various biological immunoassays. In addition, a conjugate of the polypeptide of the present invention and immunoglobulin G is useful for fabrication of various immunosensors/immunochips and for drug screening.

Immunoglobulin is a glycoprotein that functions as an antibody that neutralizes external antigens such as viruses and bacteria. It is found in blood or tissue fluids. Immunoglobulin G is the most abundant immunoglobulin, and is an important substance that protects the body by invoking an immune response by binding with exogenous substances.
Binding between immunoglobulin G and an exogenous substance is called an immune response. Using this characteristic, primary immunoglobulin G that recognizes a specific antigen is produced, and secondary immunoglobulin G that binds to primary immunoglobulin G is produced by an immunological reaction of mice or rabbits which are most frequently used as animal species. The produced immunoglobulins G are used in biological immunoassays.
However, in the production of secondary immunoglobulin G that binds to primary immunoglobulin G, there are problems in terms of the use of experimental animals and the time and costs necessary for hybridoma production and culture. In addition, a post-treatment process is required to link the enzyme and fluorescent marker for signal detection by a chemical reaction. In this process, a problem arises in that the efficiency of the final product is reduced due to the structural instability of secondary immunoglobulin G. In addition, the limit of detection appears due to the non-specific reactivity and cross-reactivity of secondary immunoglobulin G.
Under this background, the present inventors have designed a novel polypeptide capable of substituting for conventional secondary immunoglobulin G by use of the protein repebody. The repebody means a polypeptide prepared by fusion of the N-terminus of internalin B having a leucine-rich repeat (LRR) structure and VLR based on the structural similarity therebetween so as to have an optimal consensus design. The repebody has a size equal ⅕ of that of antibody, and can be produced in Escherichia coli in large amounts at low costs, and has very high thermal and pH stabilities. Thus, it is highly advantageous for industrial applications. In addition, it was demonstrated that the binding affinity of the repebody for a target substance could be easily increased to picomole levels and had very high specificity for a target substance.
The present inventors previously developed a repebody that binds specifically to human immunoglobulin G (Korean Patent Application No. 10-2013-0081009). However, the developed repebody has a disadvantage in that it has specificity only for human immunoglobulin G and does not bind to mouse or rabbit immunoglobulin G which is generally used in biological immunoassays.
Accordingly, the present inventors have made extensive efforts to solve the above-described problems and to develop a protein that binds specifically to mouse or rabbit immunoglobulin G (specific protein binder), and as a result, have found that when a mutation library is constructed using repebodies and a novel polypeptide having a specific binding affinity for mouse or rabbit immunoglobulin G is screened by module-based affinity amplification, the screened repebody exhibits better effects than conventional immunoglobulin G in various immunoassays, thereby completing the present invention.

Polypeptide selectively binding to immunoglobulin G of mouse or rabbit and use thereof

KOREA ADVANCED INSTITUTE OF SCIENCE AND TECHNOLOGY


A nanoparticle coated with a semiconducting material and a method for making the same. In one embodiment, the method comprises making a semiconductor coated nanoparticle comprising a layer of at least one semiconducting material covering at least a portion of at least one surface of a nanoparticle, comprising: (A) dispersing the nanoparticle under suitable conditions to provide a dispersed nanoparticle; and (B) depositing at least one semiconducting material under suitable conditions onto at least one surface of the dispersed nanoparticle to produce the semiconductor coated nanoparticle. In other embodiments, the nanoparticle comprises a fullerene. Further embodiments include the semiconducting material comprising CdS or CdSe.

1. Field of the Invention
This invention relates to the field of fullerenes and more specifically to the field of coating fullerenes with coatings capable of emitting and/or absorbing light.
2. Background of the Invention
Nanoparticles have been increasingly studied due to their physical and chemical properties. One such property is the ability of some nanoparticles to emit light. For instance, CdS nanoparticles have been used on photoconducting materials to increase photoconductivity and also to produce light emitters. Typically, photoluminescence of quantum dots of nanoparticles is accomplished by irradiating the quantum dot with light of a frequency that results in emission of light at a different, lower frequency. The nanoparticle quantum dots are typically incorporated into structures such as diodes to enhance the photoluminescence of the structures. Such structures are typically much larger than nanoparticle size. The nanoparticles are usually coated on the structures by a sol-gel type reaction.
A drawback to photoluminescence of semiconductor dots is that the emitted light is typically not polarized. For instance, the aspect ratio of light emitted from the quantum dot is typically too low for polarization. Further drawbacks include the size of the coated structures. For instance, the size of the coated structures may be too large for applications on the nano-scale such as the in-vivo environment. Other drawbacks include the long reaction times typically involved with the sol-gel type reactions
Consequently, there is a need for a more efficient process for coating light emitting and/or absorbing semiconductor materials on structures. Other needs include an improved process for illuminating the semiconductor materials. Additional needs include a process for coating light emitting and/or absorbing semiconductor materials on structures that can be used for applications on the nano-scale.

Fabrication of light emitting film coated fullerenes and their application for in-vivo light emission


An apparatus includes: a first clamping mechanism having a first hollow portion that includes a first gripping die portion disposed therein and a second hollow portion that includes a second gripping die portion disposed therein such that a first well drilling component is positioned therebetween; a wedge-shaped plate positioned above the first clamping mechanism and including a first end having a notch formed therein and a second arcuate end having gear teeth formed therein; a second clamping mechanism supported by the wedge-shaped plate and including a first hollow portion having a first gripping die portion disposed therein and a second hollow portion having a second gripping die portion disposed therein such that a second well drilling component is positioned therebetween; and a drive mechanism. Operation of the drive mechanism rotates the wedge-shaped plate and the second clamping mechanism through about a 90° range of motion.

1. Field of the Invention
The present disclosure is generally directed to an apparatus for connecting and disconnecting tubular members and, more particularly, to an apparatus for connecting and disconnecting well drilling components.
2. Description of Related Art
In the oil and gas industry, a drill string is used by a drilling rig to drill a well bore. The drill string is typically composed of drill pipe and a bottom hole assembly. The bottom hole assembly typically includes a drill bit, drill collars, and other drilling related tools. An automated apparatus, commonly known as an "Iron Roughneck", may be utilized to makeup (i.e., connect) and breakout (i.e., disconnect) threaded joints of drill pipe in a drill string. Iron Roughnecks have been used in the drilling industry for several years and are commercially available from a number of suppliers.
An Iron Roughneck generally comprises a two-piece wrench unit that provides the torque necessary to makeup or breakout the connection between two well drilling components. The bottom wrench, which serves as a backup wrench, grasps the tool joint of the drill pipe suspended in the rotary table or mousehole. The upper wrench grasps the tool joint of the pipe suspended from the derrick and applies either the final makeup or the initial breakout torque to the connection.
Various deficiencies exist in these prior art Iron Roughneck devices. First, the upper wrench of current Iron Roughneck designs can only rotate approximately 30°. This limitation in swing on the conventional Iron Roughnecks often necessitates two or more "bites" on the portions of the well drilling component to break the connection. In addition, the upper wrench and the bottom wrench each include a pair of faces having dies positioned thereon for gripping the well drilling component. During use of the Iron Roughneck, these dies wear and eventually need to be replaced. Current Iron Roughneck designs involve removing bolts that secure the dies or driving the dies out of dovetail slots in the clamp with a hammer in order to remove and replace the dies. Such removal processes run the risk of dropping the dies downhole.
Accordingly, a need exists for an apparatus for connecting and disconnecting well drilling components that includes an upper clamping mechanism capable of rotating 90° around the axis of the well drilling component. In addition, a need exists for an apparatus for connecting and disconnecting well drilling components that includes dies for gripping the well drilling component that can be easily and quickly removed and replaced.


A method for error detection and correction of a memory, preferably a flash memory that utilizes existing on-chip circuitry to implement the error correction and detection process is disclosed. The present invention is able to detect and correct single bit errors, while detecting multi-bit errors in data storage circuitry. The method is embodied in a software routine, which when actively operative, uses a multiply accumulate circuit (MAC) and on chip cache located on memory controller circuitry for error correction of errors incurred through the storage of data to a storage device.

Over the years, multitudes of memory testing methods have been developed. One such method makes use of a microprocessor coupled to a flash memory. The flash memory is programmed on a word-by-word basis. After each programming operation, the word just programmed is verified by the microprocessor. The verification operation is initiated by the microprocessor writing a program verify command into a command register of the flash memory. The program verify operation stages the flash memory for verification of the word last programmed. The flash memory applies an internally-generated margin voltage to the word. The microprocessor then performs a read cycle to output the word from the flash memory to the microprocessor. The microprocessor then compares the data word read from the flash memory to the data word that the microprocessor intended to program into the flash memory. A successful comparison between the programmed word and the time data means that the word was successfully programmed. If the data was not successfully programmed, then the program and verify steps are repeated with a limit of, for example, 25 attempts to program the word.
A secondary method of flash memory verification includes placing a flash memory system into a special programming mode. The special programming mode includes programming a plurality of words, by means of hashing, into the memory without the memory performing internal program verification. Hashing is a scheme for providing rapid access to data items which are distinguished by some key. A key is a value used to identify a record in a database, derived by applying some fixed function to the record, and is often simply one of the fields. The key may also be obtained by applying some function, e.g. a hash function, to one or more of the fields, and each data item to be stored is associated with a key.
The special programming mode allows the host processor to program a series of words by means of hashing and then store the words with their keys in the memory. Copies of the hash values are stored in the processor. A comparison is made between the memory stored hash values and the processor stored hash values to see whether the hash values are the same or different. The special programming mode is then exited and internal program verification by the memory is enabled. The comparison of the hash values allows the system to detect if the words were stored properly.
These and other methods of prior art memory verification tend to have the drawback that, while storage errors can be recognized (through the use of special circuits not typically found in processors), they can not be corrected. Furthermore, prior art memory correction systems and methods require separate error detection circuitry to be implemented, which can often be costly and take up valuable circuit area.


A removable magnetic dental appliance is provided. The magnetic dental appliance can be used in the treatment of various conditions, including but not limited to, snoring, sleep apnea, some forms of temporomandibular joint pain or inflammation, myofascial pain or bruxism. The appliance includes an upper arch attachment member and a lower arch attachment member, each for removably engaging at least a portion of the dentition. A magnetic component is positioned anteriorly on one of the upper arch attachment member or the lower arch attachment member and a non-magnet magnet-attracted element is provided on the other arch attachment member for magnetic engagement with the magnetic component when the upper and lower arch attachment members are substantially vertically aligned. The appliance uses magnetic force to selectively position the mandible while still permitting movement of the mandible relative to the maxilla for improved comfort.

Various fixed and removable dental appliances have been employed in dentistry and orthodontics over the years.
Removable dental appliances have been used to treat conditions such as snoring, sleep apnea, bruxism, myofascial pain, and pain and inflammation associated with temporomandibular joint (TMJ) dysfunction. While several prior art appliances have been shown to be effective, they typically lack comfort thereby negatively impacting patient compliance. Patient compliance is key in any patient-driven treatment, since lack of compliance renders the treatment ineffective.
The act of positioning an acrylic splint, or biteguard, over the teeth of the upper or lower dentition has been shown to relax tense musculature. This is accomplished by the splint preventing the existing occlusion (bite) from controlling the jaw-to-jaw relationship at maximum intercuspation (Dawson (1989). Evaluation, Diagnosis, and Treatment of Occlusal Problems (2nd Ed). Saint Louis, Mo.: Mosby, pg. 184-190). Because all corrective tooth inclines are separated, permissive splints, or de-programmers, allow the muscles to function according to their own coordinated interactions, thus eliminating the cause and the effects of muscle incoordination. Any splint design is permissive if it unlocks occlusal incline contacts and provides a smooth gliding surface that permits uninhibited muscle positioning of the mandible. Separation of the posterior teeth substantially reduces the contractile strength and activity of the elevator muscles. Thus, the loading pressure against the joints is lessened.
Advancing the mandible can relieve pain associated with some types of TMJ dysfunction, including extracapsular TMJ pain. It is very common for patients with TMJ pain and discomfort to hold their lower jaw forward during the day and, in doing so, the mandibular condyles do not impinge on the tender retrodiscal tissues (as in retrodiscitis) or the inflamed capsular ligament (as in capsulitis). However, this conscious positioning of the jaw is lost during sleep. A removable dental appliance for opening the bite and/or advancing the mandible slightly, worn during sleep, can be quite effective in relieving extracapsular TMJ pain.
Bruxism is a condition characterized by parafunctional clenching and grinding of the teeth which can occur during wake or sleep. Bruxism causes wear and breakdown of the teeth (dentition) and the subject is generally unaware of their destructive behavior. For patients who suffer from bruxism, providing a splint over the upper and/or lower teeth protects the occlusal surfaces of the teeth from destructive forces generated during bruxing. Advancing the mandible slightly, as well as providing occlusal (bite) contact on the anterior segment of the appliance lessens the amount of force that can be generated by the bruxing patient, since forces are reduced when the posterior teeth are not engaged. Advancing the mandible slightly after opening the bite can further reduce clenching forces. Reduction in grinding and clenching can also relieve muscle pain and reduce the frequency and severity of headaches associated with bruxism.
Headache sufferers diagnosed with TMJ syndrome are typically treated with a jaw-repositioning appliance, designed to relieve pressure on the distressed temporomandibular joint and to allow a proper jaw-to-skull relationship. Typical of these are the orthotics or splints described in U.S. Pat. Nos. 4,671,766 and 4,519,386. The appliance covers the upper and/or lower posterior teeth and dictates jaw position by guiding the opposing jaw into the "normal" position. Unfortunately, the posterior teeth of the upper and lower jaws are approximated by way of the appliance, thus allowing the full force of the clenching to persist.
U.S. Pat. No. 5,085,584 discloses an intraoral discluding device for the prevention of tension, migraine headaches and TMJ syndrome caused by chronic clenching of the posterior mandibular and maxillary teeth by the temporalis muscle. The discluder is a small intraoral device having a dome-shaped tab supported by a conventional palatal arch attachment member which is retained by bent orthodontic wire. The device is inserted in the mouth and retained against the upper anterior teeth with the tab extending such that, as the mouth is closed, the tab comes into contact with the lower anterior incisal edges before the posterior teeth can touch each other. This renders the temporalis muscles ineffective, preventing high pressure clenching of the posterior teeth. This device does not provide a means of advancing the mandible.
Although it is well known that advancing the mandible can relieve TMJ pain and reduce bruxing, the concept of advancing the mandible to open the airway, such as to treat apnea or snoring, is relatively new to the field of dentistry.
Apnea is generally defined as a cessation of breathing, or airflow, lasting 10 seconds or more. Hypopnea generally refers to a 50% reduction in airflow for 10 seconds or more. Sleep apnea is classified as central, obstructive, or mixed apnea. In central sleep apnea, the respiratory, or chest, muscles make no attempt to breathe as a result of a CNS disorder, resulting in a loss of oxygen to the lungs. In obstructive sleep apnea (OSA), the respiratory muscles attempt to inspire but a blockage in the upper airway prevents air from reaching the lungs. In mixed apnea, the patient presents with a combination of these problems. It should be noted that oral appliance therapy typically cannot address central or mixed sleep apnea.
Upper airway resistance syndrome (UARS) is characterized by loud snoring that causes frequent awakening. An UARS patient has all the symptoms of OSA but without the apneic or hypopneic events. Snoring is generally caused by a relaxing of the pharyngeal musculature leading to restriction of the airway, causing vibration of the surrounding tissue upon the passage of air. The tongue as well as the soft palate are believed to be major causative factors in both snoring and obstructive sleep apnea.
When a subject is positioned in the supine position, the tongue falls to the back of the throat and blocks the airway. Moving the mandible forward widens the airway, thereby preventing or reducing snoring.
Sleep apnea is associated with an increased risk of hypertension and other cardiovascular and cerebrovascular diseases. Advancing the mandible has been shown to draw the tongue out of the airway, thereby opening the airway, to reduce episodes of snoring and obstructive sleep apnea. A recent epidemiological study of the general population reported that sleep breathing disorders, especially obstructive sleep apnea syndrome, are more prevalent in populations with tooth grinding (3.4 to 4.8%) than in those without (1.4%) (Kato et al. Bruxism and Orofacial Movements During Sleep. In, Attanasio and Bailey (eds.). Sleep Disorders: Dentistry's Role. Dental Clinics of North America, 45(4), 2001, p. 658). Severe occlusal wear (more than 20% of the clinical crowns) may indicate severe bruxism and complicate oral appliance therapy (Lowe. Oral Appliances for Sleep Breathing Disorders. In, Kryger, Roth and Dement (eds). Principles and Practice of Sleep Medicine (3rd Ed.). Philadelphia, Pa.: Saunders, 2001, pp. 930).
Various appliances for advancing the mandible have been developed over the years. Most of the two-piece appliances on the market today, i.e. appliances having both an upper and lower arch attachment member, serve to fix a patients jaw in the forward position during sleep. However, pain and discomfort result when the jaw is restricted from movement for extended periods of time. Many known two-piece appliances do not allow sufficient translational or sagittal jaw movement while the appliance is in place. Many also restrict vertical jaw movement. Discomfort reduces patient compliance, thereby reducing the overall effectiveness of the patient-driven treatment. Since patient compliance increases with the comfort and ease of using a dental appliance, there is a need to develop more comfortable dental appliances.
U.S. Pat. No. 5,427,117 discloses a dental device for preventing snoring and improving breathing, which includes an upper and lower arch attachment member of a deformable material in which a mold of the subject's upper and lower teeth is formed. A post extends from the upper arch attachment member and contacts the lower arch attachment member so that the lower jaw is extended forward, thereby reducing snoring. The device is designed to permit some movement of the lower jaw for improved comfort. In a particular embodiment, the forward location of the post, with respect to the user, is adjustable to allow titration of the degree of mandibular advancement. In a preferred embodiment, the upper and lower jaws are "locked" such that they cannot be opened more than a predetermined amount. Translational or lateral jaw movements are restricted as well. U.S. Pat. Nos. 5,365,945, 5,566,683, 6,305,376 and 6,845,774 describe similar devices.
In an attempt to offer improved comfort to the patient, a device called the SILENSOR™ snoreguard was developed, which creates tension between upper and lower arches to advance the mandible. The device consists of two transparent arch attachment members, or splints, one each for the upper and lower jaw. The lower jaw is held in a predetermined position by two connectors that are fixed laterally to the arch attachment members. The connector members are oriented in such a manner as to draw the jaw forward. The device permits limited movement of the lower jaw since the connector members offer a somewhat elastic property.
The above-mentioned appliances all require rigid mechanical components (i.e. hooks, wires, plastic fasteners, etc.) in order to produce advancement of the mandible. Mechanical components are subject to wear and destruction and can render an appliance bulky and cumbersome for a patient to wear. Furthermore, locking fasteners can snag the soft tissue in the oral cavity, including the tongue, causing discomfort and even lesions.
A magnetic dental appliance for treatment of snoring and sleep apnea was recently developed and studied in Sweden (Bernhold et al., Am J Orthod Dentofacial Orthop 1998; 113, 144-55). This device incorporates 8 magnets (2 in each posterior quadrant) in an "open field" configuration to advance the mandible. The magnets are embedded in an upper and lower acrylic arch attachment member in the posterior segment of each member. The magnets are positioned in both members such that the north poles of the magnets in one member attract the south poles of the magnets in the opposing member to urge the mandible forward. Strong magnetic attraction between the upper and lower sets of magnets essentially prevents jaw movement, which causes significant discomfort to the patient since the jaw muscles and TMJ are held in the same position for extended periods. The appliance is not titratable so no adjustability is permitted once the appliance is cast.
The use of magnets in the oral cavity is not an entirely new concept. Magnets have been used to fasten dentures to implant fixtures for a number of years now. The original systems employed the attractive forces between coated Alnico V magnets, implanted in the mandible, and magnets embedded in the dentures. These original systems met with little success due to insufficient holding power. Since the introduction of rare earth magnets in the 1970's to 1980's, such as samarium-cobalt and neodymium-iron-boron magnets, it has become possible to produce magnets with small enough dimensions for dental applications and yet still provide the necessary forces.
The first magnetic denture attachment devices were of the "open field" type, wherein two unshielded magnets are placed in the oral cavity in force-coupled relationship. Due to concerns about the possible harmful effects of "open field" magnetic forces on the local tissues, most magnetic denture systems are now of the "closed field" type. In this type of system, a soft magnetic or ferromagnetic material, such as ferritic or martensitic stainless steel or Pd—Co—Ni alloy, is implanted into the jaw, rather than a magnet, to provide attractive force to hold the denture in place. This implant is known as a "keeper". In this configuration, the magnetic field lines are shunted through the keeper as it is the path of minimum energy and there is no magnetic field experienced in the oral cavity.
U.S. Pat. Nos. 6,659,771, 5,678,998, 5,013,243 and 6,299,450 describe small yet powerful magnets for cooperating with a non-magnet implanted "keeper" for denture attachment. The non-magnet keeper is made of a magnet-attracted material, such as a soft magnetic or ferromagnetic material, but is not a permanent magnet.
Magnets have been employed in aspects of orthodontics and dentistry other than denture attachments. U.S. Pat. No. 4,396,373 describes a removable orthodontic appliance for intruding one or more teeth. The appliance includes two rigid caps having internal shapes conforming to the crown portions of juxtaposed molars in the maxilla and mandible, respectively. The caps are adapted to be removably secured to said teeth. Two permanent magnets carried by the two caps, respectively, having facing poles which are in registry when the mouth is normally closed, exert a magnetic force in a direction substantially normal to the occlusal plane. The opposing magnets have confronting poles with like-polarity such that the magnets repel and develop intrusive forces upon the respective teeth.
U.S. Pat. No. 4,671,767 discloses both fixed and removable orthodontic devices that use magnets to correct Class II malocclusions. The magnets are secured to removable or fixed orthodontic devices and are positioned bilaterally in the posterior molar regions. The faces of the magnets are oriented such that they repel each other, thereby creating magnetic forces parallel to the occlusal plane for urging the mandible forward. Correction of Class II malocclusions involves, among other things, acting upon the mandible to urge it anteriorly until the jaw muscles adapt and, if possible, until regrowth of the condyle into the glenoid fossa occurs. Alignment of the teeth may be corrected in the process.
The magnetic orthodontic devices described above employ "open field" magnetic configurations, which are potentially harmful to the local tissues in the oral cavity, especially since the devices are designed for long-term use. Furthermore, the appliances are uncomfortable to wear.
Biological safety testing of magnets containing rare earth elements has evaluated both the effects of the static magnetic field and possible toxic effects of the materials or their corrosion products. These studies have demonstrated negligible cytotoxic effects of the magnetic field. However, it is of paramount importance to prevent corrosion from occurring. A clinical, histological, and immunohistochemical study, found no adverse long term effects on human buccal mucosa which had been in contact with acrylic-coated neodymium iron boron magnets and subject to the static magnetic field (Bondmark et al. Long-term effects of orthodontic magnets on human buccal mucosa: a clinical, histological and immunohistochemical study. European Journal of Orthodontics 1998; 20, 211-218). The evidence currently available from biological safety testing would suggest that the risk of harmful biological effects are negligible (Noar and Evans. Rare Earth Magnets in Orthodontics: An Overview. British Journal of Orthodontics 1999; 26(1), 29-37).
A subgroup of patients using oral appliance therapy, particularly those who suffer from sleep bruxism, experience considerable jaw discomfort the morning after wearing a rigid, single jaw position, oral appliance. A need to develop oral appliances that could allow for lateral jaw movement, as well as some degree of vertical jaw opening, was identified (Lowe. Oral Appliances for Sleep Breathing Disorders. Kryger, Roth and Dement (eds). Principles and Practice of Sleep Medicine (3rd Ed.). Philadelphia, Pa.: W B Saunders, 2001, pp 931).
It is desirable to provide an improved removable dental appliance for treatment of conditions such as snoring, obstructive sleep apnea, bruxism, myofascial pain and TMJ syndrome, that is simple and durable in construction and, most importantly, comfortable and safe for the patient. Comfort is an important factor in any patient-directed treatment where compliance is key.


Inline methods for forming a photovoltaic cell electrode structure, wherein the photovoltaic cell includes a semiconductor substrate having a passivation layer thereon, includes providing a plurality of contact openings through the passivation layer to the semiconductor substrate, selectively plating a contact metal into the plurality of contact openings by printing electroless plating solution into the plurality of contact openings to deposit the contact metal, depositing a metal containing material on the deposited contact metal, and firing the deposited contact metal and the deposited metal containing material. The metal containing material may include a paste containing a silver or silver alloy along with a glass frit and is substantially free to completely free of lead. The methods may also use light activation of the passivation layer or use seed layers to assist in the plating.

Described herein are methods for forming multiple-layer electrode structures for silicon photovoltaic cells, that is, for silicon solar cells. The methods provide an inline process which reduces manufacturing costs. The methods also provide silicon solar cells having low contact resistance with a small contact area, and thus an improved contact resistivity over electrode structures formed with the use of glass frit. The methods also are able to provide reduced environmental concerns compared to the use of lead-based glass frit, a significant advancement as solar energy is a so-called "clean" energy.
Solar cells are typically photovoltaic devices that convert sunlight directly into electricity. Solar cells typically include a silicon semiconductor that absorbs light irradiation, such as sunlight, in a way that creates free electrons, which in turn are caused to flow in the presence of a built-in field to create direct current (hereinafter "DC") power. The DC power generated by several photovoltaic (PV) cells may be collected on a grid associated with the cells. Current from multiple PV cells is then combined by series and parallel combinations into higher currents and voltages. The DC power thus collected may then be sent over wires, often many dozens or even hundreds of wires. The DC power may also be converted to AC power using well-known inverters.
To form metal contacts able to gather and convey the generated power, the solar cell material is metallized. For silicon solar cells, metallization typically comprises forming a grid-like metal contact, for example including fine fingers and larger busbars, on a front surface of the cell and forming a full area metal contact on the back surface of the cell. Conventionally, metallizing silicon solar cells is done by screen printing. Screen printing has been used for decades, and is a robust, simple, rapid, and cost-effective metallization method and can be easily automated for large-scale solar cell manufacturing. In a conventional screen printing approach to the metallization of solar cells, a squeegee presses a paste through a mesh with a pattern that is held over the wafer. A typical paste for solar cell metallization consists of a mixture of silver particles, a lead-based glass frit and an organic vehicle. When the wafer is fired (annealed), the organic vehicle decomposes and the lead-based glass frit softens and then dissolves the surface passivation layer, creating a pathway for the silver to reach the silicon base by forming a multitude of random points under a silver pattern formed by the paste. The surface passivation layer, which may also serve as an anti-reflection coating, is a dielectric layer, such as a silicon nitride layer, and is an essential part of the cell covering the cell except for electrical contact areas. Upper portions of the silver paste densify into one or more films that carries current from the cell. These films form gridlines on the front-side of the wafer. The silver of the paste is also a surface to which tabs connecting adjacent cells may be soldered.
While the use of a lead-based glass frit combined with screen printing has advantages, it also has several drawbacks. First, contact resistivity, or specific contact resistance, is very large, for example, specific contact resistance between the semiconductor emitter layer (sun-exposed surface) and the silver gridline is on the order of about 10−3 Ω·cm2. This specific contact resistance between the silicon semiconductor emitter layer and the silver gridline is several orders of magnitude higher than the specific contact resistance that may be reached in semiconductor integrated circuit devices, which is on the order of about 10−7 Ω·cm2. The large contact resistivity is the result of a low effective contact area between the silicon semiconductor emitter layer and the silver electrode gridline due to the non-conductive glass frit occupying a considerable portion of the interface. Due to the large specific contact resistance, the emitter layer in a solar cell must be heavily doped and large contact area between the emitter and silver gridline must be used, otherwise the silver of the paste cannot make good electrical contact to the silicon. The heavy doping kills the minority carrier (holes) lifetime in the top portion of the cell and limits the blue response of the cell, and the large contact area generates higher surface recombination rate. As a result, the overall efficiency of the solar cell is reduced.
Another problem with the glass frit approach is a narrow process window. The narrow process window may be a problem because a thermal cycle, that fires the gridline, must burn through the silicon nitride to provide electrical contact between the silicon and the silver without allowing the silver to shunt or otherwise damage the junction. This narrow process window severely limits the process time to the order of about 30 seconds and temperature band to about 10° C. around the peak firing temperature.
Still further, the use of lead-based glass frit, required to dissolve portions of the passivation layer, raises environmental concerns.
Ideally, a metallization technology for silicon solar cells should form the gridline electrodes with low specific contact resistance and thus low contact area, high conductivity, good solderability, and long time stability. Because it is very difficult for a single layer electrode to meet all these requirements, several methods for forming multiple-layer electrode structures have been proposed for silicon solar cells.
U.S. Patent Application Publication No. 2007/0169806, incorporated herein by reference in its entirety, discloses forming multiple-layer gridline front surface electrodes by forming contact openings through the passivation layer using a non-contact patterning apparatus such as a laser-based patterning system. The contact openings may be filled by inkjet printed nanophase metallic inks and covered with silver gridlines. However, several problems associated with using printed nanophase metallic inks for filling the contact openings include quality and availability of the nanophase metallic inks, the wetting behavior and contact characteristic between the nanophase metallic ink and the silicon surface in the contact openings, and the process compatibility of nanophase metallic ink with firing silver gridlines.
U.S. Patent Application Publication No. 2004/0200520 discloses a multiple-layer backside electrode structure that is formed by making contact openings through chemically etching the passivation or anti-reflection coating layer, followed by sputtering or evaporating a three layer-seed metal stack to form the contact with emitter and plating copper and a thin metal capping layer to form gridlines. However, chemically etching the passivation layer involves several extra process steps including applying an etch resist layer, patterning the etching resist layer, and striping off the etching resist layer after patterning the passivation layer.
U.S. Patent Application Publication No. 2005/0022862 discloses screen printing a liquid ink pattern layer devoid of particles onto the silicon oxide passivation layer to form a particle-devoid ink pattern layer as an etching protection mask.
U.S. Pat. No. 6,194,032 discloses a selective substrate metallization method using a plating gel. However the plating gel contains a polymeric thickening agent, rather than a conventional liquid-type electroless plating solution.
There are several disadvantages to using traditional bath electroless plating to metallize solar cells. Traditional electroless plating is a batch process, where articles are removed from the manufacturing line, plated, then returned to the manufacturing line. Solar cell manufacturing, however, prefers to utilize an inline manufacturing process. As such, after loading the articles onto a conveyor belt, it is expected that all the processing steps can be finished by keeping the articles on the conveyor. Therefore, batch processing has been difficult to implement into solar cell manufacturing. Additionally, because electroless plating typically occurs at elevated temperatures, such as about 90° to 100° Celsius, and the plating solution may contain some aggressive compositions of acids and bases, it may destroy the nitride antireflection coating layer, especially on multicrystalline silicon solar cells.
It is still deemed desirable to develop more rapid, cost efficient and/or less complex methods of forming metallization contact structures for solar cells that provide low contact resistance, low contact area, high conductivity, high solderability, and high stability from solar exposure.

This patent is subject to a terminal disclaimer.

Solar cell metallization using inline electroless plating