A method and device for vaporizing a liquid reactant. A vaporizing plate having a top surface defines a liquid flow channel, the channel being laterally delimited by edges having a height greater than a minimum thickness of liquid reactant required to generate vapor under film or nucleate boiling regime. A heating system is associated to the vaporizing plate for heating the liquid reactant over a minimum temperature required to generate vapor under nucleate or, preferably, film boiling regime. A cap covers the vaporizing plate to collect the vapor at a predetermined pressure and provided with a vapor exit and a liquid feeder feeds the liquid reactant onto the vaporizing plate.

Optical fibres for telecommunication typically are high-purity, silica-based glass fibres drawn from glass preforms, which preforms can be produced according to various glass deposition techniques.
Some of these deposition techniques, including vapor axial deposition (VAD) and outside vapor deposition (OVD), require the use of a combustion burner for generating glass soot particles to be deposited. This burner is usually fed with a silica precursor, such as SiCl4, together with combusting gases, so that a high temperature flow of forming fine glass (i.e. SiO2) particles is generated. This flow is directed onto a rotating target for growing a glass soot preform, which is subsequently consolidated for obtaining a glass preform. Optionally, the burner may be fed also with a doping material, such as GeCl4, for suitably modifying the refractive index of the glass.
The different gases are provided to the burner by means of a gas delivery system, comprising gas sources and pipe connections. It is important to have a glass precursor material source able to generate the precursor material at a controlled rate, without undesired fluctuations in time.
Several types of gas delivery systems and gas sources are known in the art for such a use.
U.S. Pat. No. 4,314,837 relates to a method for delivering vaporous source materials to an oxidizing reaction flame or the like. Each constituent (for example SiO2, GeO2 and B2O3) is maintained in liquefied form in an enclosed container that is provided with a heater for raising the temperature of the liquid to a value sufficient to provide a predetermined vapor pressure within the reservoir. The resultant vapours are transferred by means of individually controlled metering means and appropriate conduits to the reaction device. Oxygen may be added to the vapour-conveying conduit or directly to the vapor utilization device. The reservoirs may be commercially-available pressurized tanks. The reservoir pressure is monitored, and the information thus derived is used to control the operation of heaters. Mass flow controllers are provided in the different lines, so that the mass flow rates of the vapours can be controlled.
The Applicant has verified that such a vaporizer has the drawback of being subject to undesired pressure fluctuations. The Applicant also observes that the presence of these reservoirs inside the laboratories wherein researchers and technicians have to operate may be dangerous, because of leakage risk. Moreover, the Applicant notices that the described system requires the use of mass flow controllers, which are expensive and fragile devices, along the vapor flow lines, i.e. in hot points of the system, where they are subjected to errors or failures. The Applicant also observes that these tanks have to contain a relatively large amount of liquid and are therefore cumbersome.
U.S. Pat. No. 5,707,415 discloses a vaporizer (film evaporator) for halide-free, silicon-containing liquid reactants used in producing preforms. The vaporizer includes a plurality of packed-bed columns surrounding a central tube. A mixture of liquid reactant, e.g., octamethylcyclotetrasiloxane, and gas, e.g., oxygen, is sprayed onto the top surfaces of the columns by a set of spray nozzles. The liquid reactant and the gas flow downward together through the columns and are heated by hot oil that flows around the columns' walls. The liquid reactant evaporates into the gas until the dew point temperature is reached, at which point all of the liquid reactant will have been converted into vapour. The vapour/gas mixture exits the bottom surfaces of columns, where its direction of flow changes from downward to upward. This change in flow direction separates higher molecular weight species from the vapour/gas mixture. The vapour/gas mixture leaves the vaporizer through central tube and is supplied to soot-producing burners where it is used to produce preforms.
U.S. Pat. No. 5,078,092 relates to a system for delivering a liquid reactant at high flow rates to an oxidation/flame hydrolysis glass soot deposition site. A first liquid reactant (TiCl4) is delivered onto an inner surface of a flash vaporization chamber to form a thin film and is mixed with oxygen after vaporization. Additional vaporized reactants (SiCl4) are thereafter mixed with the vaporized first liquid prior to delivery to an oxidation/flame hydrolysis burner to form a glass soot outer cladding layer on a soot preform. Said inner surface of the flash vaporization chamber is defined by a heating element, whose temperature is maintained below the temperature at which nucleate or film boiling of the liquid occurs.
U.S. Pat. No. 5,356,451 relates to a method and apparatus for providing reactant vapours to a utilization site. The apparatus includes a vaporization chamber enclosed by top and bottom walls, side walls and first and second end walls. The first end wall is elevated with respect to the second end wall. The reactant is supplied in liquid form to a flow distributor that delivers the liquid to that portion of the bottom wall near the first end wall. The angle with which the bottom wall is inclined with respect to horizontal is sufficient to cause the liquid to flow down the bottom wall at a rate sufficient to form a film, the thickness of which is smaller than that thickness which would support a bubble during heating of the film (i.e. no boiling occurs). The surface is heated to a temperature greater than the boiling point of the liquid, thereby converting the liquid reactant to a vapor that is delivered to the vapor utilization site.
An object of the present invention is to provide an alternative type of vaporizer, which guarantees high vaporization rates, which is safe and which has reduced dimensions.

Method for vaporizing a liquid reactant in manufacturing a glass preform


A method is described for growing at least one silicon carbide (SiC) single crystal by sublimation of a SiC source material. Silicon, carbon and a SiC seed crystal are introduced into a growing chamber. Then, the SiC source material is produced from the silicon and the carbon in a synthesis step that takes place before the actual growing. The growing of the SiC single crystal is then carried out immediately after the synthesis step. The carbon used is a C powder with a mean grain diameter of greater than 10 xcexcm.

The invention relates to a method for growing at least one silicon carbide (SiC) single crystal by sublimation of a SiC source material.
The sublimation of industrial-grade SiC in powder form and growing the SiC in a gas phase on a monocrystalline SiC seed crystal is a method for the production of a SiC single crystal known from German Patent DE 32 30 727 C2. The gas mixture that is formed during the sublimation primarily contains the components Si, Si2C, SiC2 and SiC. The gas mixture is also referred to below as xe2x80x9cSiC in the gas phasexe2x80x9d. The source material used is usually industrial-grade silicon carbide in granular form and of high purity, the silicon carbide preferably having a grain size of approximately 200 to 300 xcexcm. The SiC source material is produced prior to the growing process of the SiC single crystal and is introduced as a prepared source material into a growing chamber.
The article titled xe2x80x9cSiC-Bulk Growth By Physical-Vapor Transport And Its Global Modelingxe2x80x9d, by D. Hofmann et al., Journal of Crystal Growth, Vol. 174, 1979, pages 669 to 674 describes a method for the synthesis of a SiC powder which is used as a source material from elemental silicon (Si) granules and carbon (C) powder.
Another method for producing the source material in the form of SiC powder is known from the article titled xe2x80x9cImprovement In The Growth Rate Of Cubic Silicon Carbide Bulk Single Crystals Grown By The Sublimation Methodxe2x80x9d, by H. N. Jayatirtha et al., Journal of Crystal Growth, Vol. 174, 1997, pages 662 to 668. In this case, high-purity silicon and high-purity carbon react with one another for a total of three hours at 1800xc2x0 C. Then, the powder is removed from the reaction furnace and is subjected to further treatment steps. In particular, a three hour oxidation is carried out at 1200xc2x0 C., in order to remove excess carbon. Then, an etching step is carried out, in order to eliminate traces of SiO2 that have formed as a result of the oxidation.
A common feature of all the above-mentioned methods for the production of the source material in the form of the SiC powder is that the production of the SiC powder and the actual growing of the SiC single crystal represent individual processes that are carried out independently of one another.
By contrast, Published Japanese Patent Application JP 6-316 499 A describes a method for the production of an SiC single crystal which in one first process step also includes the formation of the SiC source material from silicon and carbon as an integral part of the growing process. The growing operation in the narrower sense takes place as a result of the sublimation of the SiC source material produced in the previous process step and as a result of deposition of the SiC in the gas phase on an SiC seed crystal. The starting materials used for the production of the SiC source material are carbon in the form of a graphite block or carbon (C) powder with a grain diameter of below 10 xcexcm and granular silicon with a grain diameter of between 2 and 5 mm. The grain diameter of the silicon is given as a parameter that is not critical and, if appropriate, may also assume values outside the diameter range stated. However, for the C powder employed it is expressly stated that if the grain size is over 10 xcexcm only the surface of the C powder reacts with silicon, and therefore the SiC source material formed is not suitable.
In a second embodiment, in which a graphite block of porous graphite with a relative density of 0.5 g/cm3 is used instead of the C powder, the production process of the SiC source material and the growing process of the SiC single crystal do not take place within a single process sequence. The growing chamber is opened again after the SiC source material has been produced, in order for the SiC seed crystal to be introduced. Only then is the actual growing commenced. The relative density of the porous graphite used may also adopt values other than 0.5 g/cm3. The upper limit specified is a relative density of 1.0 g/cm3, since at higher levels SiC source material is no longer formed in sufficient quantities.
The process conditions during the production of the SiC source material involve a temperature in the range between 1150xc2x0 C. and 1800xc2x0 C. and a pressure of less than 200 Torr, corresponding to approximately 266 mbar.
When using C powder with a grain diameter of less than 10 xcexcm, the reaction taking place during the production of the SiC source material can very easily lead to fluidization of particles, in particular of the C powder. As a result, deposits are formed on the SiC seed crystal, which has an adverse effect on the quality of the growing which is then to be carried out.
It is accordingly an object of the invention to provide a method for growing SiC single crystals that overcomes the above-mentioned disadvantages of the prior art methods of this general type, which avoids the fluidization of the C powder which occurs in the prior art and therefore leads overall to an improved quality of the SiC single crystal which is grown.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method for growing at least one silicon carbide (SiC) single crystal by sublimation of an SiC source material. The method includes introducing silicon (Si), carbon (C) and an SiC seed crystal into a growing chamber, the carbon being a C powder with a mean diameter of powder grains of greater than 10 xcexcm. Producing the SiC source material from the silicon and the carbon in a synthesis step carried out before a growing step; and carrying out the growing step by growing the SiC single crystal immediately after the synthesis step.
The invention is based on the recognition that, unlike in the customary procedure used in the specialist field, which is defined by the technical teaching disclosed by Published Japanese Patent Application JP 6-316 499 A, the use of C powder with a mean grain diameter of greater than 10 xcexcm is still possible and even advantageous. On account of the larger geometry and the consequently higher weight, this measure avoids the undesirable fluidization of the C powder during the production of the SiC source material. Therefore, during this process step there is no undesirable deposition on the SiC seed crystal, which is already in the growing chamber while the SiC source material is being produced. The recognition that C powder even with a mean grain diameter of greater than 10 xcexcm reacts with the silicon so well that the result is a SiC source material of high quality which is eminently suitable for the subsequent growing of the SiC single crystal is particularly surprising.
The carbon used may be both synthetic and natural carbon.
In a first preferred configuration, the C powder has a mean grain diameter of greater than 20 xcexcm, and in particular of greater than 30 xcexcm. The larger the mean grain diameter, the more successfully the undesirable fluidization of the C powder is suppressed.
An embodiment in which the C powder is selected to have a grain size which is less than 200 xcexcm and preferably less than 80 xcexcm is also advantageous. If the grain size is below the upper limits given above, all the carbon inside the powder grain still reacts with the silicon. By contrast, if a C powder with a larger mean grain diameter is provided, the carbon actually only reacts with the silicon at the surface of the powder grain. As a result, there is an undesirable excess quantity of unbonded carbon and silicon atoms in the SiC source material.
Another advantageous embodiment of the method involves a type of carbon in which the reaction with the silicon to form the SiC source material takes place endothermally or at least without significant amounts of energy being released being used for the carbon in the C powder. This is because undesirable fluidization of particles, in this case of both carbon and silicon particles, may also be caused by an exothermic reaction between the silicon and the carbon. The chemical energy released in this case leads to the undesirable fluidization with the adverse effects described above. With the preferred types of carbon mentioned, the reaction with the silicon takes place in particular without volumetric expansion. Thermoanalytical investigation of the reaction reveals that energy is absorbed or energy is released only to such a slight extent that it is too low to fluidize particles.
With a view to achieving a reaction between the C powder and the silicon which proceeds as far as possible without any energy being released, a variant in which a type of carbon whose powder grains are composed of a multiplicity of individual crystallites is particularly advantageously used. In this case, one powder grain preferably contains at least 10 to 20 crystallites. The polycrystalline structure of the individual grains then makes a decisive contribution to an overall reaction that proceeds substantially without energy being released. During heating, the silicon melts first. Prior to this, there is virtually no reaction between the two elements. The melting is endothermic. When melting commences, the reaction of the SiC synthesis, which in itself is exothermic, also starts. On account of the polycrystalline structure of the C powder grains, the synthesis reaction proceeds not only at the grain surface but also in the interior of the grains. Since the endothermic melting and the exothermic synthesis reaction take place substantially in parallel, the energy balance is practically neutral. In the case of a type of carbon whose powder grains contain only a few crystallites, by contrast, the two subreactions proceed successively. The advantageous energy compensation then cannot occur, and the energy that is released during the synthesis leads to undesirable fluidization of particles.
An embodiment in which the silicon is selected to be in the form of a silicon (Si) powder is also preferred. In this case, the maximum mean grain diameter of the Si powder is one millimeter. The mean grain diameter is preferably in a range between 100 xcexcm and 400 xcexcm. Compared to the grain size of the C powder, the mean grain diameter of the Si powder is a much less critical parameter. The reaction between silicon and carbon to form the SiC source material preferably takes place at temperatures of over 1400xc2x0 C. Since at these temperatures silicon is no longer in the powder form which was originally introduced, but rather is already in molten form, it is possible to select a significantly larger mean grain diameter for the Si powder than for the C powder.
The silicon, which has become liquid as a result of the melting operation, impregnates the carbon, so that the mixing between the silicon and carbon is determined almost exclusively by the mean grain diameter of the C powder. The upper limit for the mean grain diameter of the Si powder is determined by the fact that if the mean grain diameters are too large, the melting operation takes too long and therefore the carbon cannot optimally be impregnated by molten silicon.
To achieve mixing which is as homogeneous as possible for the reaction between the silicon and carbon, according to an advantageous configuration the Si powder and the C powder are intensively mixed together and then introduced into the growing chamber as a mixture which is as homogeneous as possible. As a result of the intensive mixing, the reaction yield during the production of the SiC source material is improved.
In a preferred variant embodiment, the growing chamber, in preparation for the production process of the SiC source material, is evacuated for several hours at a temperature of between 1000xc2x0 C. and 1300xc2x0 C., in particular 1200xc2x0 C., until a pressure of less than or equal to 10xe2x88x924 mbar is reached. After the evacuation, the growing chamber is filled with an inert gas, in particular with argon (Ar), helium (He) or hydrogen (H2). An inert gas pressure in a range between 100 and 1000 mbar is set.
A variant embodiment in which the silicon and the carbon are heated to a synthesis temperature of at least 1200xc2x0 C. and at most 1900xc2x0 C. is also advantageous. A synthesis temperature in the range between 1400 and 1600xc2x0 C. is particularly advantageous, since in this temperature range on the one hand the silicon has already melted and impregnated the carbon and on the other hand the reaction to form the SiC source material takes place with a good yield. The synthesis temperature is maintained for a period of at most three hours, in particular of only at most one hour, so that the silicon which is introduced into the growing chamber and the carbon which is also introduced react with one another as completely as possible and form the desired Sic source material.
A particular advantage of the method resides in no further cooling of the growing chamber and, if appropriate, removal of the SiC source material from the growing chamber after the SiC source material has been produced, since these steps could introduce undesirable impurities into the SiC source material. Therefore, an advantageous variant embodiment involves the growing chamber, starting from the conditions for the production of the SiC source material, being brought to the growing conditions for the SiC single crystal. This results in a rise in the temperature of the SiC source material from the synthesis temperature to a temperature of between 2100xc2x0 C. and 2500xc2x0 C. Moreover, at the same time the overall pressure that prevails during the production of the SiC source material is also reduced to at most 30 mbar. Under these conditions, SiC is sublimed out of the SiC source material and then precipitates out of the gas phase on the SiC seed crystal. To ensure corresponding material transport of the SiC in the gas phase, a temperature gradient is established between the SiC source material and the SiC seed crystal or the SiC single crystal that is being formed.
By suitably selected orientations of the SiC seed crystal, it is possible to grow a SiC single crystal of a specific polytype. Therefore, in advantageous embodiments there is provision for the SiC seed crystal to be disposed in the growing chamber in such a way that the SiC single crystal grows on a C side or an Si side of the SiC seed crystal in the direction of a polar axis. The growth on the C side provides a 4H-SiC single crystal, whereas the growth on an Si side provides a 6H-SiC single crystal.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method for growing SIC single crystals, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.


A class of diphenylmethylaminoacetamide derivatives is described having use in treatment of CNS dysfunctions such as epilepsy and convulsive disorders. Compounds of most interest are those of the formula ##STR1## wherein each of X and Y is independently selected from hydrido and halo; and wherein each of R.sup.1, R.sup.2 and R.sup.3 is hydrido; or a pharmaceutically-acceptable salt thereof.

Convulsive disturbances are typically observed in humans as rapidly alternating contractions and relaxations of muscles which are manifested by irregular movements of the limbs or body and typically accompanied by unconsciousness. The most common cause of convulsions in human adults is epilepsy. Convulsive seizures occur in children from a variety of causes. Convulsions in children may be due to brain damage from birth injuries, or due to dietary deficiencies such as a lack of vitamin D, or due to metabolic disorders such as hypoglycemia or hypokalemia, or due to a sudden body temperature elevation caused by infections such as pneumonia. Convulsions may also be initiated by brain diseases such as meningitis, encephalitis or tumors, and also by conditions brought on by asphyxia or skull fracture.
Acetamide derivatives have been investigated for various CNS uses. For example, Belgian Patent No. 706,262 describes a class of tricyclic compounds, namely, diphenylenemethane amine and amide derivatives, mentioned for use as anti-convulsants, as well as for anti-depressive, anti-inflammatory and analgesic uses. U.S. Pat. No. 3,821,249 describes another series of tricyclic-type dibenzothiazepin derivatives asserted to possess psychostimulant, anti-depressive, analgesic, anti-tussive, anti-histaminic and gastric anti-secretory properties. U. S. Pat. No. 4,639,468 describes a class of 2-amino-acetamide derivatives, having use in treatment of epilepsy, dyskinesia such as Parkinsonism, memory troubles and psychic disorders such as depression, with mention in particular of the compound diphenylpropylacetamide.
Various acetamide derivative compounds have been investigated for other pharmaceutical uses. For example, U.K. Patent No. 1,181,673 describes a series of tricyclic xanthen and thiaxanthen urea derivatives having utility in treatment of peptic ulceration. Carcinogenicity studies have been carried out involving a family of N-(9-acridinyl)glycylglycylglycine compounds [R.M. Peck et al, J. Med. Chem., 19 (12), 1422-1423 (1976)]. A family of acridinylglycine derivatives has been reported to have tumor-inhibiting properties [B. Wysocka-Skrzela, Pol. J. Chem., 56 (10-12), 1573-1576 (1982)]. Belgian Patent No. 636,245 describes a family of 2-(.omega.-alkoxycarbonylalkylideneamino)acetamides having pharmaceutical properties.
Diphenylmethylaminoacetic acid derivatives have been described as intermediates or end products of various laboratory-scale synthetic methods, without mention of pharmaceutical utility. For example, a series of N-benzhydrylaminoacetic acid compounds have been synthesized as intermediates for preparation of N-benzhydrylaminoacetic acid esters or derivatives, two such intermediates being 2-(diphenylmethylamino)acetamide and 2-[di-(para-methoxyphenyl)methylamino]acetamide [A. G. de Vazquez et al, Anales Asoc. Quim. Argentina, 60, 501-507 (1972)]. The compound .alpha.-diphenylmethylaminoacetamide was incidentally sythesized as a by-product in a multi-step preparation of a series of 3-oxo-1,2-diazetidinium ylides [E. C. Taylor et al, J. Am. Chem. Soc., 103, 7743-7752 (1981)].
Other types of acetamide derivatives, such as glycinamide compounds, have been described for various purposes. For example, German Patent No. 2,511,311 describes a family of glycinamides for use as fungicides.

Diphenylmethylaminoacetamide derivatives as anti-convulsants


A gas discharge display unit having a partition wall structure which is useful for forming discharge cells suitable for the color image display with high precision is provided. A plurality of cathode electrodes are formed on a front panel. A plurality of anode buses, anode electrodes, auxiliary electrodes and resistors are formed on a back plate. A layer insulating film is formed on the back plate where the anode buses, the anode electrodes and the resistors are provided except for a display electrode portion. A display electrode is formed on the upper face of the anode electrode. Then, a three-layered insulating layer having differing quantities of a resin binder is formed on the layer insulating film. Unnecessary portions are removed by a sand blasting step to form partition walls comprised of partition layers. A phosphor is applied onto the layer insulating film in a discharge cell except for the display electrode portion. The front plate is joined to the back plate with the partition walls held therebetween in such a manner that the cathode ray tube is orthogonal to the anode bus.

Recently, a gas discharge display unit (plasma display panel) has been utilized as a plane-type display unit for an information terminal such as a portable computer. The gas discharge display unit has been applied widely because the display is clear and the angle of visibility is greater than that of a liquid crystal panel.
Furthermore, the size of a television picture receiver has been increased so that a projection-type television using a projection cathode ray tube or a liquid crystal panel has been marketed. However, the brightness of the screen and the size of the device have caused problems.
On the other hand, the coloring technology of the gas discharge display unit has recently been developed remarkably. The depth of the unit can be reduced more than that of the cathode ray tube. Consequently, attention has been paid to the gas discharge display unit as the best wall-type television for high visibility. In addition, it is expected that colors will be accurately reproduced and that brightness and lifetime will be enhanced.
An example of a memory driving type DC gas discharge display unit according to the prior art will be described below with reference to FIG. 8. As shown in FIG. 8, a plurality of stripe-shaped cathode electrodes 22 are formed on a front plate 21, which is made of a transparent glass or the like. A plurality of stripe-shaped anode buses 24a are formed on a back plate 23, which is made of a transparent glass or the like. The front plate 21 is opposed to the back plate 23 with a plurality of partition walls 25 held therebetween in such a manner that the cathode electrodes 22 are orthogonal to the anode buses 24a. Thus, a lot of discharge cells 26, which are surrounded by the partition walls 25, are formed like a matrix. The peripheral portions of the front plate 21 and the back plate 23, which are combined, are sealed by a low melting point glass or the like. Discharge gases whose main component is an inert gas are filled in the discharge cell 26.
Anode electrodes 24b are individually formed corresponding to respective discharge cells 26 on the back plate 23. A display electrode 27 is formed on each anode electrode 24b in the discharge cell 26. The display electrode 27 is connected to the anode bus 24a by a resistor 28. Thus, a pair of discharge electrodes are formed in the discharge cell 26 by the cathode electrodes 22 and the display electrode (anode) 27. In FIG. 8, the reference numeral 31 designates an auxiliary electrode for generating auxiliary discharge so as to easily start discharge in the discharge cell 26.
A layer insulating film 30 is formed on the back plate 23, except for the display electrode 27 portion, on which the anode bus 24a, the anode electrode 24b and the resistor 28 are formed. Consequently, discharge can be prevented from occurring between a plasma in the discharge cell 26 and the anode bus 24a or resistor 28. A phosphor 29 is applied onto the layer insulating film 30 in the discharge cell 26 except for the display electrode 27 portion.
The front plate 21 is transparent except for the cathode electrode 22 portion. The surface of the phosphor 29 can be directly observed through the discharge cell 26.
The cathode electrode 22, the anode bus 24a, the anode electrode 24b, the display electrode 27, the resistor 28, the layer insulating film 30, the phosphor 29, the partition wall 25 and the like are formed, by thick film printing technology, on the front plate 21 or the back plate 23 which is made of the glass plate or the like.
In order to increase the pixel density and reproduce the finer images in the above structure similarly to the high visibility television, it is necessary to form partition walls forming discharge cells hyperfinely. More specifically, the partition wall having a height of 160 to 200 .mu.m and a width of 50 to 60 .mu.m should be formed. In particular, 1 dot should be formed by three discharge cells R, G and B in order to display color images. Hence, if fine images are to be displayed, it is necessary to form partition walls having a very small size and highly precise dimensions.
A method for forming the partition walls of a gas discharge display unit according to the prior art will be described with reference to the drawings. FIGS. 9(a) to 9(c) are views showing the steps of forming partition walls in the gas discharge display unit according to the prior art. FIG. 10 is a view schematically showing the sand blasting step. In FIGS. 9(a) to 9(b) and 10, the components that are not related to the formation of partition walls are omitted.
As shown in FIG. 9(a), a rib paste 32 for forming a partition wall 25 is applied, by the knife coating method, onto a back plate 23 made of a transparent glass or the like on which an anode electrode 24b is formed. Then, the rib paste 32 is dried and solidified. Then, a photosensitive film 33 is fixed onto the rib paste 32 as shown in FIG. 9(b). Thereafter, ultraviolet rays are irradiated on the photosensitive film 33 through an exposure mask on which partition patterns are formed, and the sensitized portion is developed and removed to form a mask pattern 34 as shown in FIG. 9(c). As shown in FIG. 9(d), abrasive particles such as glass beads are jetted on the rib paste 32 by means of a sand blasting device having a jet gun 35. Consequently, the rib paste 32 is cut except for the portion on which the mask pattern 34 is formed. Finally, the mask pattern 34 is removed by using a peeling agent as shown in FIG. 9(e). Thus, the partition walls (25) are formed on the back plate 23.
As shown in FIG. 10, the back plate 23 is moved in one direction and the sand blasting device (jet gun 35) reciprocates in the direction perpendicular to the direction of movement of the back plate 23 above the mask pattern 34 on the back plate 23. In this state, the abrasive sand such as glass beads are jetted through the nozzle of the jet gun 35. Consequently, the rib paste 32 on the portion where the mask pattern 34 is not formed is cut and removed.
In order to fabricate the gas discharge display unit according to the prior art, a material for the partition wall is applied over the whole glass substrate by the thick film printing technology, and unnecessary portions are removed at the sand blasting step so that the partition wall is formed. In other words, the material for the partition wall should have the following characteristics: (1) adhesion to the glass substrate, (2) cutting properties for the sand blasting step, (3) adhesion to a resist for a mask during sand blasting, (4) durability against a peeling agent used for peeling and removing the resist after the rib paste is cut, and the like. However, it is very hard for the material for the partition wall material according to the prior art to satisfy all these characteristics.
According to the partition wall having the above structure and the method for manufacturing the same, the shape and dimension of the partition wall have limitations, that is, a width of (100.+-.10) .mu.m and a height of (200.+-.5) .mu.m. In addition, the pitch of the discharge cells is at best (650.+-.10) .mu.m. Accordingly, it is very hard to form fine partition walls and discharge cells having high densities for forming pixels that can reproduce images with high precision.
According to the method for manufacturing the gas discharge display unit according to the prior art, the rib paste is generally cut and removed by sand blasting by means of a sand blasting device having a jet gun. FIG. 11 shows the influence on the cutting rate of the rib paste and the amount of side etching of the partition wall by the jet pressure of the abrasive sand which is applied during sand blasting by means of the jet gun. FIG. 12 shows the influence on the cutting rate of the rib paste and the amount of side etching of the partition wall exerted by the distance between the rib paste and the jet gun (jet distance). As shown in FIG. 11, when a jet pressure P is raised, a cutting rate Rs of the rib paste is increased and the amount Es of side etching of the partition wall is increased at a greater ratio than the cutting rate Rs. If the jet pressure P is set to a relative value having a smaller amount Es of side etching, i.e., 3 or less so that the injection distance must be reduced so as to raise the cutting rate Rs, the amount of side etching is increased again as shown in FIG. 12. As shown in FIG. 13(a), the partition wall 25 should have a rectangular shape in section. However, the partition wall 25 has a concave curved face so that the width of the section on the central portion thereof is reduced. For this reason, the precision and strength of the partition wall are reduced.

Gas discharge display panel and its fabrication method


The invention relates to biologically active dibenzodiazepinone analogs represented by Formula I, to methods of producing them, to pharmaceutical compositions comprising them and to methods of treating neoplastic conditions.

The euactinomycetes are a subset of a large and complex group of Gram-positive bacteria known as actinomycetes. Over the past few decades these organisms, which are abundant in soil, have generated significant commercial and scientific interest as a result of the large number of therapeutically useful compounds, particularly antibiotics, produced as secondary metabolites. The intensive search for strains able to produce new antibiotics has led to the identification of hundreds of new species.
Many of the euactinomycetes, particularly Streptomyces and the closely related Saccharopolyspora genera, have been extensively studied. Both of these genera produce a notable diversity of biologically active metabolites. Because of the commercial significance of these compounds, much is known about the genetics and physiology of these organisms. Another representative genus of euactinomycetes, Micromonospora, has also generated commercial interest. For example, U.S. Pat. No. 5,541,181 (Ohkuma et al.) discloses a dibenzodiazepinone compound, specifically 5-farnesyl-4,7,9-trihydroxy-dibenzodiazepin-11-one (named "BU-4664L"), produced by a known euactinomycetes strain, Micromonospora sp. M990-6 (ATCC 55378). ECO-4601 (Compound 1) and Micromonospora sp. strains 046-ECO11 and [S01]046 are disclosed in U.S. Ser. No. 10/762,107, incorporated by reference in its entirety. ECO-4601 was also disclosed in Charan et al. (2004), J. Nat. Prod., vol 67, 1431-1433, and Igarashi et al. (2005), J. Antibiot., vol 58, no 5, 350-352. Its use for the treatment of cancer is disclosed in U.S. Ser. No. 10/951,436 and 11/130,295, both incorporated herein by reference in their entirety.

Synthetic dibenzodiazepinone analogs were disclosed in the published Canadian patent application 2,248,820 as having anti-histamine properties.
Although many biologically active compounds have been identified from bacteria, there remains the need to obtain novel compounds with enhanced properties. Thus, there exists a considerable need to obtain pharmaceutically active compounds in a cost-effective manner and with high yield. The present invention solves these problems by providing new therapeutic compounds and methods to generate these novel compounds by post-biosynthetic chemical modifications.

This patent is subject to a terminal disclaimer.

Dibenzodiazepinone analogues, processes for their production and their use as pharmaceuticals


The invention provides for torrefaction apparatus which includes a drum (14) having a biomass inlet (18) and a torrefied material outlet (20), furnace means (16) external of the drum (14) for heating the drum (14) so that torrefaction temperature is achieved in the drum, and a gas inlet conduit (42) leading to the drum (14) from a source of inert gas, thereby to create an torrefaction atmosphere in the drum (14).

Global warming, the emerging energy crisis, and the depletion of fossil fuel resources such as oil have created a need for more environmentally friendly solutions to provide energy. Several ideas and technologies are known to produce energy, and to confront the challenges associated therewith, although many of these technologies are not yet available on a commercial scale.
One solution to the energy crisis is to use biomass or bio fuel to address our energy shortages. Biomass or bio fuel is material derived from recently living organisms, which includes plants, animals and their by-products. It is a renewable energy source, unlike other natural resources such as petroleum, coal, and nuclear fuels.
The use of biomass fuels can contribute to waste management. One method of making biomass more efficient as an energy source is torrefaction.
Torrefaction is a thermo-chemical treatment method of biomass at temperatures between 200 to 500° C. at low oxygen conditions (Pyrolisis). The result of this process on the untreated biomass is to produce a product that is dry, hydrophobic and easily millable with an increased energy density that burns cleanly.
The torrefied biomass is hydrophobic, has lower moisture content, produces less smoke when burnt, has higher calorific values compared to untreated biomass, and is suitable for various applications as a fuel.
Known methods of producing torrefied biomass have an overall processing inefficiency and are expensive to implement, and harm the environment by emitting smoke. Furthermore, in some known torrefaction methods such as that disclosed in United States patent application 2003/0221363, the oxygen level has to be controlled, to prevent the torrefaction product being subjected to burning.
This invention seeks to provide an apparatus and a process for creating torrefied biomass that has a high output of torrefied biomass, a relatively low initial investment cost, and minimizes damage caused to the environment during the process.


A rail rolling apparatus and method of use, the apparatus having a back end portion with one or more apertures, a middle portion, and one or more hooks which are capable of substantially receiving the base of a railroad rail. The apertures are sized to receive one or more backhoe bucket teeth. When positioned with the railroad rail and the backhoe bucket, the method of use allows the backhoe bucket to repair or fix rolled over rail and bent rail, and further allows for positioning or lining of track via various movements of the bucket or backhoe arm.

The art of the present invention relates to the railroad construction and maintenance fields in general and more specifically to apparatuses and devices within those fields that assist an employee or contractor with new track construction, track maintenance, track rehabilitation, and track salvage operations.
Modern railroad track typically uses rails made of hot rolled steel with a profile of an asymmetrical rounded I-beam. Known as flat bottom rail or T-section rail, it is the dominant rail in worldwide use today. The rail has a top or head portion, a middle or web portion, and a foot or base portion which can rest directly on the railroad tie or the corresponding plate. When the rail is installed, the base portion is generally angled in relation to a horizontal plane and this angle is known as the base angle. Most typical rail sections or 'sticks' are approximately 39 feet long unless its continuous welded rail (CWR), in which case, each rail or 'stick' can be 500-600 feet long and welded to another rail or 'stick'.
For numerous reasons, track rail sections must be routinely moved and positioned or repositioned in relation to other rail sections or in relation to the cross-ties such that the rail profile is maintained thereby considerably enhancing rail service life. Also, one of the most common causes of railroad accidents or derailments is rail roll-over. The forces generated between the moving train wheel and the rail can be resolved into two components, a lateral force (L) and a vertical force (V). If the moment generated by the lateral force (L) is greater than the moment generated by the vertical force (V), the rail can rotate about its corner or roll-over.
When a rail has rolled-over, especially in a derailment scenario, the traditional repair procedure is for a group of workers, commonly known as a "rail gang" to slide a chain under the foot or base portion of the rail and hook one end of the chain onto the high side of the rolled rail at the foot or base portion of the rail. The other end of the chain is then wrapped around a cribbing bucket attached to a backhoe and rolled or pulled by the cribbing bucket back away from the rail and towards the backhoe. This tightens the chain and rolls the rail back down into or onto one or more steel plates in order that the rail may be re-attached to the cross-tie using one or more railroad spikes. The one or more steel plates in conjunction with the spikes hold the rail to the cross-ties. This traditional repair procedure, utilizing a chain, cannot be used to reposition or set bent rail back into the one or more plates where it could be re-attached using one or more spikes. Additionally, the chain used in this traditional repair procedure can and does periodically break creating a dangerous safety concern.
The present art rail rolling apparatus and method of use allows rolling, repositioning, and setting of rails without the deleterious effects of the prior art. The apparatus generally comprises a back-end portion, a middle portion, and one or more hooks. The back-end portion is capable of receiving a removable attachment, such as a cribbing or other type of bucket or implement of a typical piece of mechanized earth moving equipment such as a backhoe. The one or more hooks are capable of receiving a base portion of a railroad track rail. The present art rail rolling apparatus improves upon and replaces the prior art chain for rail roll-over and repair and eliminates the safety concerns related to breaking chains. The present art also allows for productivity increases since using the present art rail rolling apparatus is much faster than using chains to roll or reposition a rail. Additionally, the present art rail rolling apparatus and its method of use is capable of setting bent rail back in position into the one or more plates. As discussed, the prior art repair procedures which utilize chains does not allow the bent rail to be precisely rolled back into the one or more plates. Also, the present art rail rolling apparatus and method of use is capable of lining track without the requirement of touching the rail with the cribbing bucket. That is, contacting the rail with the cribbing bucket, as is typical with the prior art track lining method, can cause chips and cracks in the rail which could cause track failure and/or train derailment.
Accordingly, it is an object of the present invention to provide a rail rolling apparatus and method of use which allows for the safe repair of a rolled-over rail, the safe repair of a bent rolled over rail, and the safe movement of a rail section, such as when lining track.
Another object of the present invention is to provide a rail rolling apparatus and method of use which is capable of repairing rolled-over rail more quickly than with traditional apparatuses and techniques and therefore significantly increasing productivity and reducing costs for railroad service crews.
A further object of the present invention is to provide a rail rolling apparatus and method of use which is capable of repairing bent rolled-over rail without the replacement of the bent rail sections as is typically required with the traditional means.
A yet further object of the present invention is to provide a rail rolling apparatus and method of use capable of also lining track without having to touch the top or head of the rail with the bucket of the backhoe thereby eliminating any potential damage to the rail.

Rail rolling apparatus and method of use


Included are: a radar main unit for emitting a radar wave and receiving a reflection wave of the radar wave reflected by an object; and a dielectric substrate in which multiple matching layers each having a protruded shape are regularly arranged on one surface of the dielectric substrate, and the radar wave emitted from the radar main unit enters the multiple matching layers in a state where the other-surface side of the dielectric substrate is attached to a windshield.

In late years, various sensors are attached to vehicles. For example, millimeter-wave band radar devices (hereinafter referred to as radars) are used for measurement of distance from an object. Since such radars perform measurement using an electromagnetic wave in the millimeter wave band, they are effective at night when using sensors of optical bands entails difficulty. Meanwhile, the radars are often attached to the bottom of the vehicle or in the back of the emblem from the viewpoint of design. However, there is a possibility that the performance of radars is greatly deteriorated at these attachment positions as described below.
A radar attached to the bottom of a vehicle is greatly affected by multipath formed by the reflection wave of a radar wave reflected by the ground. For example, a null direction in which the radar reception sensitivity is greatly reduced is formed in the detection area due to the multipath wave.
Alternatively, in a radar attached to the back of an emblem, there are cases where the radar wave is scattered by the emblem and thus an appropriate beam pattern is not formed. This is a major factor that degrades the detection performance of the radar.
Meanwhile, Patent Literature 1 describes a radar installed in a vehicle compartment. This radar is attached inside the vehicle compartment at an upper part of the windshield. As a result, the influence of the multipath wave on the radar is reduced, and the design is not impaired since the radar is not exposed to the outside of the vehicle. However, if the scattering and loss of the radar wave in the windshield are large, the gain of the radar is greatly reduced, and thus the detection range shrinks.
Meanwhile, the radar described in Patent Literature 1 includes a dielectric layer provided on the windshield. It is difficult to reduce the loss of electromagnetic waves propagated by the windshield since it largely depends on the physical properties of the material of the windshield. However, the reflection of electromagnetic waves by the surface of the windshield is reduced by providing the dielectric layer.


The present invention relates to a cryoablation catheter, comprising an outer tubular body with a closed distal end to form a fluid cooling chamber and an inner tubular member having a proximal end adapted to receive fluid suitable for cryoablation and a distal end coupled to a fluid expansion nozzle wherein the inner tubular member is movable in an axial direction to thereby change the position of the nozzle within the fluid cooling chamber.

1. Field of the Invention
The present invention relates to a cryoablation catheter, and more particularly to a cryoablation catheter for creating long lesions.
2. Description of the Prior Art
Many medical procedures are performed using minimally invasive surgical techniques wherein one or more slender implements are inserted through one or more small incisions into a patient""s body. With respect to ablation, the surgical implement may include a rigid or flexible structure having an ablation device at or near its distal end that is placed adjacent to the tissue to be ablated. Radio frequency energy, microwave energy, laser energy, extreme heat, and extreme cold may be provided by the ablation device to destroy the tissue.
With respect to cardiac procedures, a cardiac arrhythmia may be treated through selective ablation of cardiac tissue to eliminate the source of the arrhythmia. A popular minimally invasive procedure, radio frequency (RF) catheter ablation, includes a preliminary step of conventional electrophysiology mapping followed by the creation of one or more ablated regions (lesions) in the cardiac tissue using RF energy. Multiple lesions are frequently required because the effectiveness of each of the lesion sites can not be predetermined with exactness due to limitations of conventional mapping. Often, five lesions, and sometimes as many as twenty lesions may be required before a successful result is attained. Usually only one of the lesions is actually effective.
Deficiencies of radio frequency ablation devices and techniques have been overcome by ice mapping prior to creating lesions, as taught by U.S. Pat. Nos. 5,423,807; 5,281,213 and 5,281,215. However, even though combined cryogenic mapping and ablation devices permit greater certainty and less tissue damage than RF devices and techniques, both the cryogenic and the RF devices are configured for spot or roughly circular tissue ablation.
Spot tissue ablation is acceptable for certain procedures. However, other procedures can be more therapeutically effective if multiple spot lesions are made along a predetermined line, or a single elongate or linear lesion is created in a single ablative step. Radio frequency ablation devices are known to be able to create linear lesions by dragging the ablation tip along a line while the ablation electrode is energized.
The present invention provides a cryogenic ablation system including a cryoablation catheter which is particularly well suited for creating elongated lesions.
In accordance with one aspect of the present invention, there is provided a cryoablation catheter which includes an outer tubular member capable of insertion into the vessels of the body, a sealing cap disposed at the distal end of the outer tubular member for forming a cooling chamber at the distal end of the catheter, and an inner tubular member which is slidably disposed within the outer tubular member. A fluid expansion nozzle is disposed on the distal end of the inner tubular member. The cryoablation catheter also includes a control means coupled to the proximal end of the inner tubular member for moving the inner tubular member longitudinally within the outer tubular member to thereby change the position of the fluid expansion nozzle within the cooling chamber. Preferably the fluid expansion nozzle takes the form of a Joule-Thompson nozzle. By moving the nozzle longitudinally within the cooling chamber it is possible to create a continuous long lesion along the entire length of the movement of the nozzle.
In accordance with another aspect of the present invention, the inner tubular member is disposed coaxially within the outer tubular member so as to define a passageway between the tubular members. A cylindrical support member is disposed between the inner tubular member and the outer tubular member and includes at least one aperture which extends through the support member to permit expanded fluid to return through the passageway to the proximal end of the catheter for removal from the system, or in a closed system for reprocessing for further use.
In accordance with still another aspect of the present invention, the control means takes the form of a control knob which is connected to the proximal end of the inner tubular member for controlling movement of the inner tubular member longitudinally within the outer tubular member to thereby change the position of the fluid expansion nozzle relative to the distal end of the cooling chamber.
These and other objects of the present invention will become more apparent when considered in view of the following description of a preferred embodiment of the present invention.

Cryoablation catheter for long lesion ablations


A strip seal and method of configuration thereof for sealing portions of components of a gas turbine exposed to pressure pulsations. The strip seal has a sealing face that is configured to follow the contours of first portions of the components. The strip seal further has a pressure face that has a sinusoidal curvilinear shape with respect to the sealing face. The pressure face is configured to prevent localized movement of strip seal by configuring pressure face on its first side to contact sealing face at a plurality of points, on its second side to contact second portions of the components at a plurality of points.

Strip seals, also known as feather seals, can be used to eliminate leakage flow between two components arranged adjacently to one another. This is achieved by the two components having groove recesses in edge faces that lie substantially opposite and adjacent one another. The strip seal seals the gap between the two components by being at least partially received into the groove recesses of the adjacently fitted components so as to span the gap between the components. U.S. Pat. No. 5,531,457 discloses an example of such a strip seal used to reduce leakage flow through the gap between two platforms of a blade.
The grooved recesses of fitted components often do not perfectly align due to, for example, manufacturing tolerances or as a result of thermal expansion. If the strip seal is manufactured so as to tightly fit into the groove recesses, less than perfect groove recess align would result in high stress loading of the strip seal, which can result in premature failure.
To overcome this problem strip seals can be made thinner than the height of the grooved recesses and flexible orthogonal to the strip seal length. In operation the pressure differential across the seal, due to the flexibility of the strip seal, forces the strip seal against one surface of the grooved recess so by effecting the seal. When the pressure differential is low strip seals are made thinner so as to increase their flexibility strip. To hold thin seals in place, for example during installation, the strip seal may be provided with biasing means, dispersed along the strip seal length. An example of biasing means in described in U.S. Pat. No. 3,836,279.
During operation the strip seals are exposed to periodic pressure pulsations caused by various rotating components within the gas turbine such as blades as they pass through rotating and non-rotating regions where the strip seals are contained within. These strip seals are generally placed in components like rotor blades, rotor heat shields or vane platforms and stators. The strip seals fit into the grooved recesses of components, providing a sealing between two portions of the components. A first portion faces low pressure from the hot gases, while second portion faces high pressure circulating in the gas turbine.
Depending on the strength and frequencies of the pressure pulsations, parts of the strip seal that are not biased against faces of the grooved recess or otherwise retained can be induced into periodic resonance leading to premature fatigue failure of the strip seal. This problem is particularly relevant in the sealing of components where rotating blades of the gas turbine induce pressure pulsation at sealing faces.
To overcome this problem, some strip seals designs have an arrangement of clamping projections along the length of the strip seal to suppress the damages caused due to pressure pulsations. However, these clamping projections are often worn out, as a relatively small surface area of these clamping projections makes contact with the grooved recesses of the components that are subjected to high oscillations and vibrations. There is therefore a need for a strip seal design that is resilient to fatigue failure and resonance induced by pressure pulsations caused by rotating and non-rotating components of a gas turbine.

Strip seal and method for designing a strip seal


The invention relates to a method for calibrating a smart-antenna array of a wireless access system using TDD, which antenna array comprises antenna elements with a transmit and a receive branch each. In order to enable a time stable calibration, it is proposed that at least some of the antenna elements are selected in turns to be employed for transmitting broadcast messages. This provides time periods in which only one of said elements is transmitting. Each transmit branch is connected to at least one of the receive branches of another element, signals transmitted via these connections being evaluated for calibration. If receive branches are connected to transmit branches of several elements, it is ensured with the proposed selection that during the broadcast periods these receive branches receive at the most a signal from one element, thus avoiding the need for switches. The invention equally relates to a corresponding radio transceiver unit and a corresponding calibration system.

1. Field of the Invention
The invention relates to a method for calibrating a smart-antenna array of a time division duplex (TDD) system, which smart antenna comprises an array of at least two antenna elements, each with a transmit (TX) and a receive (RX) radio frequency branch. The invention equally relates to a radio transceiver unit with a smart antenna array for a wireless access system using time division duplex, and to a calibrating system for calibrating a smart antenna array of a wireless access system using time division duplex.
2. Description of the Related Art
Smart antennas are known to be employed as transmit and receive antennas in wireless access systems, in particular in base stations of such systems. Smart antennas, which generally use an array of antenna elements, enable the output of fully steerable beams patterns. They can be employed for example for a user specific digital beamforming, in which a beamformer of the smart antenna array is able to weight phase angle and/or amplitude of the signals transmitted by different antenna elements of the array in a way that the direction of the beam is adapted to move along with a mobile terminal through the whole sector of coverage of the antenna array.
Smart, or adaptive, antennas offer several benefits for wireless communications systems. The directivity of smart antennas can be used for example to reduce the delay spread of a radio channel. Moreover, the diversity of the antenna guards against fading. When employed in a base station, the output power of mobile terminals served by the base station can be decreased due to the spatial gain, which results in a longer battery lifetime. Array antennas also serve to increase the range of base stations, and the interference power to and from neighboring cells can be lowered considerably, thus improving the signal-to-interference ratio and the overall network capacity. Finally, mobile terminals served by the same base station can be identified according to their spatial signatures. This enables to further increase capacity of the base station by serving several terminals in the same time slot in space division multiple access (SDMA) operation.
Since the smart-antenna algorithms are frequently implemented at the baseband, most smart antenna systems provide for each antenna element separate radio frequency (RF) components for transmission and for reception of signals in dedicated transmit and receive branches. The RF components of the different receive and transmit branches of the different antenna elements usually have different properties. If the differences between the antenna elements and between the different branches of each antenna element are not compensated by an array calibration, the gain of the smart antenna is degraded. Furthermore, these properties evolve differently in time, which makes a real-time calibration necessary.
Smart antennas can be employed e.g. in a time division duplex system, in which adaptive antennas are particularly effective, since the optimum pattern formed in reception mode can be used for determining an optimum transmission pattern. The properties of such a TDD system can be made use of for calibration. In a TDD system, the employed frequency channels are divided into time slots, which are alternatingly reserved for transmission in uplink and downlink direction. Therefore, there is always only one direction of transmission possible at a time. The TDD is realized by connecting alternatingly a transmit and a receive branch in each antenna element.
Kentaro Nishimori, Keizo Cho, Yasushi Takatori, and Toshikazu Hori propose in xe2x80x9cA new calibration method of adaptive array for TDD systems,xe2x80x9d in Proc. Antennas and Propagation Society, IEEE International Symbosium, 1999, vol. 2, pp. 1444-1447, a method for calibrating a smart antenna array with a plurality of antenna element for TDD systems.
In this method, first a signal transmitted via the transmit branch of a first antenna element is divided by a directional coupler in the transmit branch. The signal is received via a switchable connection by the receive branches of each of the other antenna elements in turn. Then, signals transmitted via the transmit branches of each of the other antenna elements are divided by directional couplers in the respective transmit branch. Signals divided from one of these transmit branches after the other are received by the receive branch of the first antenna element by switching between corresponding connections. For the respective transmitted and received signals, the phase differences and gains are determined, which are then used for calculating for each antenna element a calibration value that can be used for correcting at the same time phase and gain in relation to a selected reference antenna element. Phase calibration and amplitude calibration are therefore combined. Due to the fact that the method is based on a TDD system, no signals from outside of the unit comprising the smart antenna array are received during the transmissions by the antenna elements. Therefor, the evaluated received signals result exclusively from the respectively evaluated transmitted signal of the antenna array.
It is an advantage of this method that in contrast to other known calibration methods, the calibration can be carried out during normal transmissions, using the signals transmitted during these normal transmissions as calibration signals. Therefore, no additional signal generator is needed and no transmission capacity is lost.
A disadvantage of the described calibration system, however, results from the switching used for selecting different antenna elements of the antenna array. The performance of active or semi active components like switches is varying in time, the consequence of which are unstable calibration results. Furthermore, an implementation using switches can be rather expensive.
It is an object of the invention to provide a method, a radio transceiver unit comprising a smart antenna array and a calibration system that enable a time stable calibration of a smart antenna array.
This object is reached on the one hand with a method for calibrating a smart-antenna array of a wireless access system using time division duplex, which smart antenna array comprises at least two antenna elements, each with a transmit and a receive radio frequency branch. The calibrating is based on the evaluation of signals transmitted via the transmit branch of one of the antenna elements and received via the receive branch of another one of the antenna elements respectively. The transmit and receive branches used for the respective transmission are physically interconnected. At least those transmit branches of antenna elements connected to a receive branch of an antenna element that is connected at the same time to a transmit branch of at least one other antenna element are employed in a predetermined order for transmitting broadcast messages in predetermined broadcast periods during which the respective other antenna elements are prevented from transmitting signals.
On the other hand, the object is reached with a radio transceiver unit for a wireless access system using time division duplex comprising a smart antenna array with at least two antenna elements, each including a transmit and a receive branch. In the transmit and the receive branch of each antenna element a directional coupler is provided for coupling signals out of the transmit branches and for coupling signals into the receive branches. Each coupler in the transmit branch of an antenna element is connected by a physical connection to the coupler in the receive branch of at least one other antenna element. Selection means are provided for selecting in a predetermined order at least each of those transmit branches of antenna elements connected to a receive branch of an antenna element that is connected at the same time to a transmit branch of at least one other antenna element to be employed for transmitting broadcast messages in predetermined broadcast periods during which the respective other antenna elements are prevented from transmitting signals. Finally, processing means are employed for evaluating signals transmitted via said connections for obtaining calibration information to be used for calibrating the smart antenna array.
Finally, the object is reached with a calibrating system for calibrating a smart antenna array with at least two antenna elements of a wireless access system using time division duplex, each antenna element including a transmit and a receive branch. The proposed calibration system comprises directional couplers, connections, selection means and processing means corresponding to those of the proposed radio transceiver unit.
The invention proceeds from the idea that in wireless access systems, usually broadcast periods are provided, in which periods the same information is transmitted to several recipients, and in which the regular point-to-point smart-antenna operation cannot be used. In situations where the element radiation patterns of the array cover the same angular space as the radiation pattern of the whole array, it is known to use only a single one of the antenna elements of the smart antenna array for transmitting broadcast messages during the predetermined broadcast periods. If in contrast and in accordance with the invention, the antenna element employed for transmitting the broadcast messages is varied, a receive branch of an antenna element can be connected in a fixed way to the transmit branches of up to all other antenna elements taking their turn in transmitting the broadcast message. During each broadcast period, the receive branches of the antenna elements of a smart antenna array in a TDD system then receive at the most a signal from the transmit branch of the antenna element currently used for transmitting the broadcast message. Thus, switches in the calibration system are not necessary. Avoiding switches results in an improved calibration since only passive components are required, the properties of which practically do not change in time. Moreover, an expensive implementation of switches is avoided.
At the same time, there is no need for a dedicated generation of calibration signals and for the provision of a time period that can be used exclusively for calibration, since the signals transmitted anyhow as broadcast messages can be used as basis for calibration measurements, and, depending on the configuration, possibly partly as well signals transmitted during smart antenna operation.
Preferred embodiments of the invention become apparent from the subclaims.
In a first preferred embodiment, transmitted and received signals are evaluated by determining only the phase difference between them. These phase differences are then used for determining a value for a phase calibration of each antenna element. Phase calibration alone can be sufficient, if only the power received by or from some other radio transceiver unit is to be maximized. From the implementation point of view, doing phase calibration only might in some situations be easier.
In an advantageous implementation of the invention, a value for a phase calibration for each antenna element is determined by fixing a calibration phase for one of the N antenna elements to a value {circumflex over (B)}1 and by adjusting the phases of the Nxe2x88x921 further antenna elements with calibration phases {circumflex over (B)}2 to {circumflex over (B)}N determined relative to the fixed value. For the transmitted and received signals, the respective phase difference xcex94ij is then determined. The first index identifies the respective transmitting and the second index the respective receiving antenna element. Both indices i,j lie between 1 and N. For a particularly simple determination of calibration phases, pairs of phase differences xcex94ij, xcex94ji are determined, each antenna element being represented in at least one of these pairs. For example, it would be sufficient to determine the phase differences xcex941j, with j=2 to N, of signals transmitted by the first element and received by each of the other elements, and the phase differences xcex94i1, with i=2 to N, of signals received by the first elements after having been transmitted by each of the other elements.
In a next step of this implementation, calibration phases {circumflex over (B)}2 to {circumflex over (B)}N are determined based on the one hand on suitable equations {circumflex over (B)}jxe2x88x92{circumflex over (B)}i={circumflex over (x)}ixe2x88x92{circumflex over (x)}jxe2x88x92(ŷixe2x88x92ŷj), the hat {circumflex over ( )} denoting the phase of the respective variable, wherein xi is the transfer function of the transmit branch of the ith antenna element and wherein yj is the transfer function of the receive branch of the jth antenna element, and based on the other hand on suitably determined phase differences xcex94ij, the phase differences xcex94ij corresponding to {circumflex over (x)}i+ŷj and the indices i,j lying between 1 and N. In case pairs of phase differences xcex94ij, xcex94ji and were determined as proposed above, for example, the solving of equations {circumflex over (B)}jxe2x88x92{circumflex over (B)}i=xcex94ijxe2x88x92xcex94ji immediately results in the desired values for the phase calibrations of the different antenna elements.
In another preferred embodiment, transmitted and received signals are evaluated by determining alternatively or in addition to the phase differences the gains of the signals on the respective transmission path. These gains can be used for determining a value for an amplitude correction for each of the antenna elements.
An amplitude calibration is needed in particular, if the smart antenna array is to be calibrated for nulling, i.e. for placing nulls in the radiation pattern of the array for some directions.
In a preferred embodiment of the invention in which an amplitude calibration is to be carried out, first, transmitted and received signals are evaluated by determining the gain xcex94ija of the respective received signal compared to the respective transmitted signal. The first index identifies the respective transmitting antenna element and the second index identifies the respective receiving antenna element, both indices i,j lying between 1 and N, wherein N is the number of the at least two antenna elements of the array. Then, factors |Bn|, with n=1 to N, are determined for an amplitude correction for each of the N antenna elements based on the determined gains xcex94ija and on the equations:             "LeftBracketingBar"              B        n            "RightBracketingBar"        =                            "LeftBracketingBar"                      x            1                    "RightBracketingBar"                                  xe2x80x83                                  "LeftBracketingBar"                      y            n                    "RightBracketingBar"                                      "LeftBracketingBar"                      x            n                    "RightBracketingBar"                                  xe2x80x83                                  "LeftBracketingBar"                      y            1                    "RightBracketingBar"                      ,      xe2x80x83          n    =          1                    xe2x80x83                  to                    xe2x80x83                          N        .
Corresponding to the proposed equations for determining values for the phase calibration, xn is the transfer function of the transmit branch of the nth antenna element, and yn the transfer function of the receive branch of the nth antenna element. Since each determined gain xcex94ija corresponds to |xi∥yj|, the equations can be solved easily, if suitable and sufficient gains xcex94ija are determined. More specifically, the gains xcex94ija are equal to |xi∥yj| except for some multiplicative values resulting from the amplitude of the transfer functions of components on the transmit path between a respective transmit branch and a respective receive branch. These transfer functions can be supposed to be known.
The employment of the invention can be seen in particular, though not exclusively, in wireless local area networks (WLAN), like IEEE 802.11a and HIPERLAN/2 (high-performance local-area network) networks, and in wireless rooftop routers (WRR).
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.

Method for calibrating a smart-antenna array radio transceiver unit and calibrating system


A system for aggregating data descriptive of a plurality of projects and servers includes a host catalog; a host catalog server; a plurality of project servers; a plurality of project databases; a cluster including a master server and a plurality of project servers; a project database associated with each project server; an entry in the host catalog for each project server and each project database. The place catalog server executes simple aggregation on behalf of a project server which is a master non-virtual server selectively by immediate updating and scheduled updating of an entry in the host catalog for the project server; and executes complex aggregation on behalf of a cluster of servers by executing immediate updates to a master entry in the host catalog database and by executing non-immediate updates to an entry in the host catalog database for a non-virtual, non-master project server.

1. Technical Field of the Invention
This invention relates to a system and method for aggregating information descriptive of servers and projects in a multi-server environment.
2. Background Art
In computer systems, users typically have access to several or many different sites, such as URLs, applications and databases. In such systems, a user may have difficulty remembering and tracking all of these applications and databases. One approach to facilitating such is through the use of a "favorites" facility, which allows a user to add to a drop down list an entry identifying such sites. Another approach is to provide access to a database which stores project and membership information on a local system.
Such approaches have been limited to listing places, projects and databases on a single server or individual machine, and have not accounted for multi server deployments, nor for groups of servers configured in a cluster and addressed as one server.

System and method for the aggregation of place information in a multi-server system

International Business Machines Corporation


A digital camera is provided with a vertically long camera body having an approximately rectangular solid shape. An LCD panel provided in a rear surface of the camera body is arranged such that longitudinal directions of the display screen and the camera body correspond to each other. The digital camera is operated through a touch panel provided in a lower portion of the display screen. In a taking mode, an image is displayed in a small size on an upper portion of the display screen. In reproducing, the camera body is rotated sideways by 90 degree. In a reproducing mode, display posture of the image is also rotated by 90 degree, and the image is displayed in a large size on the entire display screen.

1. Field of the Invention
The present invention relates to an imaging apparatus with display and an image display apparatus, and more particularly to an imaging apparatus with display and an image display apparatus in which a horizontally long display is provided in a main body.
2. Description of the Related Arts
There has been known a digital camera in which an image taken by an image sensor such as a CCD is converted into digital data to be stored in a memory. A display such as an LCD is provided in a rear surface of a camera body of the digital camera. The display functions as an electronic viewfinder for through-displaying a live image of a subject in a taking mode, while it reproduces and displays the recorded images read out from the memory in a reproducing mode.
The camera body is downsized and becomes thinner with the spread of the digital camera; meanwhile, a display screen is getting larger in order to enhance the visibility and to display a powerful image. When the display screen is larger, it occupies more area on a rear surface of the camera body inevitably, so that a grip space for holding the camera body must get smaller relatively. When the camera body is held tightly, the display screen is partially covered by the hand holding the camera body. Accordingly, despite the large display screen, apart of the image is not watched.
In order to solve the above problem, in the camera disclosed in Japanese Patent Laid-Open Publication No. 11-289484, the recorded image is displayed on the entire display screen in the reproducing mode, while the image to be taken in the taking mode is displayed slightly smaller than the image in the reproducing mode, so that a part of the display screen used as a grip will become a blank area on which the image is not displayed.
This type of cameras have a camera body of approximately rectangular solid shape are usually a horizontal type. In the horizontal type of camera, horizontally long posture in which the camera body is laid down so as to approximately correspond the longitudinal direction of the camera body to the horizontal direction is normal posture. The normal posture of the camera body is posture in which the image having normal aspect ratio (horizontal to vertical ratio) of 4:3 for example, can be taken in the horizontally long posture (a so-called horizontal position). In such a horizontal type camera, in the taking mode one end in the horizontal direction of the camera body is grasped so as to be wrapped by one hand, and then held. Additionally, since the camera body is horizontally long, the other end is easily held by another hand, and the camera body can be held stably by both hands.
In the horizontal type camera, since a left side end portion of the camera body viewed from the front side is a grip position, a grip space is positioned in the right side as viewed from the rear surface. Accordingly, the blank area is set in the right side of the display screen, and the display size of the image becomes smaller than the size of the entire display screen. The image is displayed on the upper left side of the display screen. In the reproducing mode, the image can be reproduced in a state that the camera body is put on a table or on the hand, so that it is unnecessary to ensure the grip space as in the taking mode, and the recorded image is displayed on the entire display screen. Thereby, it is possible to watch the powerful images on the large-sized screen.
According to the market research conducted recently by the present assignee, the camera body is more often held with one hand as it is getting smaller and thinner, and the research shows that a vertical type of camera in which the normal posture is a vertically long (the longitudinal direction of the camera body approximately corresponds to the vertical direction) can be held more stably than the horizontal type which is conventionally used. The reason for that is considered as follows. When the camera body is held with one hand, a side end portion in the horizontal direction of the camera body is gripped to hold the horizontal type camera; meanwhile, a lower portion of the camera body is gripped to hold the vertical type camera. Thereby, the camera body is easily held at a position near the barycentric position of the camera body, so that fluctuation of the camera body is prevented.
Although the vertical type is easier to hold than the horizontal type in the taking mode, the camera body of the vertical type is narrower than the horizontal type, and makes it difficult to increase the width of the display. The display size is not a serious problem in the taking mode in which the display is used for framing; however, it should be as large as possible in order to show visually appealing images in the reproducing mode.
When the image having the horizontally long aspect ratio is displayed on the display screen of the camera or the image display apparatus having the horizontally long display, and if the display direction is fixed in these camera and apparatus, it is impossible to correspond to the change of the posture of the apparatus body, it is inconvenient in many cases.

Imaging apparatus with display and image display apparatus


A unique cell structure for use in flash memory cell and a method of fabricating the memory cell. More particularly, a vertically integrated transistor having a pair of floating gates is fabricated within a trench in a substrate. The floating gates are fabricated using sidewall spacers within the trench. A doped region is buried at the bottom of the trench. The structure can be fabricated such that the buried doped region provides a connecting layer in a multi-bit flash memory cell. Alternatively, the buried doped region may be used as a buried bitline in a single bit flash memory cell.

1. Field of the Invention
The present invention relates generally to a unique cell structure for use in flash memory and, more particularly, to a vertically integrated flash memory cell which implements a pair of floating gates fabricated as sidewall spacers within a trench and to a method for fabricating the memory cell.
2. Description of the Related Art
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Electronic memory comes in a variety of forms and may be used for a variety of applications. One type of commonly used memory is flash memory. Flash memory is a solid state storage device which provides easy and fast information storage. Flash memory is a type of electrically erasable programmable read-only memory (EEPROM) that can be erased and programmed through exposure to an electrical charge. Flash memory allows data to be written or erased in blocks rather than one byte at a time as with typical EEPROM devices, thereby making flash memory considerably faster.
Flash memory generally includes a grid of columns and rows forming an array of flash memory cells. Each cell generally comprises two transistors separated by a thin oxide layer. One of the transistors serves as the floating gate while the other serves as the control gate. The floating gate is coupled to the row or wordline through the control gate. Single data bits or multiple data bits can be stored in the memory cells by placing various levels of charge on the floating gate of the cell transistor. By storing differing levels of charge and thus obtaining different levels of threshold voltage Vt, a cell can store more than one bit of information therein. For example, to facilitate the storage of two binary bits, four levels of charge and corresponding levels of Vt may be used. During a read operation, a decoder senses the transition threshold Vt to determine the corresponding binary value of the multi-bit information (e.g. 00, 01, 10, 11). Disadvantageously, storing higher densities of binary bits in each cell to increase the number of voltage levels Vt used to store the higher bit densities introduces problems in the memory array including a higher operating voltage, more power dissipation, and increased circuit complexity for reading, erasing, and decoding the binary information. Further, if the number of charge levels increases without increasing the supply voltage, it becomes increasingly difficult to detect and distinguish the correct stored charge levels.
One technique for alleviating some of the problems associated with the storage of the multi-bit binary information in a memory cell is to provide two separate floating gates for each transistor within the memory cell. The control gate of the transistor is connected to a wordline provided over both floating gates while each of the source and drain regions of the transistor are connected to respective digit lines. Dual floating gate transistors distribute or partition the total charge in the transistor over each of the two floating gates, rather than a single floating gate. One advantage of dual floating gate transistors is that the dual floating gates allow for better control of the total charge in the transistor, as can be appreciated by those skilled in the art.
The processing of such structures is often costly and complex, especially with ever-increasing demands for smaller structures. Providing multi-bit flash cells and single bit flash cells incorporating dual floating gate patterns with less cumbersome and less costly processing techniques would be advantageous.

Method of fabricating a vertically integrated memory cell


Systems and methods for noise cancellation are provided. In particular, information regarding events associated with a computer providing a telephony function or associated with a hardware telephone providing a telephony function is provided to a noise cancellation process. The provided information can be used to identify specific noises associated with events, so that filters specifically adapted for removing an identified noise can be applied. Alternatively or in addition, information regarding the existence and timing of an event can be provided in order to facilitate the application of a noise cancellation filter. Noise cancellation as described can also be applied in connection with recording speech or other audio signals.

Voice telephony continues to be a primary means of communication. In order to facilitate effective voice communications, it is desirable to filter noise from the voice signal.
In order to perform noise cancellation, various noise cancellation algorithms are available. However, conventional noise processing algorithms have difficulty filtering out noises created in connection of the use of a computer, such as computer generated dings or tones, keyboard clicks, mouse clicks or output from a computer soundcard. Accordingly, conventional techniques for noise cancellation have not been particularly effective in filtering common office environment noises, such as noises generated by or associated with the operation of a computer from voice streams.
Common noise cancellation algorithms operate by estimating noise in the environment. The voice stream including noise is analyzed and the noise component is estimated and then subtracted from the outgoing voice stream. In order to improve the accuracy of such noise cancellation processes, pattern recognition may be used to estimate noise in a signal. The pattern recognition model may be trained in order to increase the amount of available pattern recognition data.
Techniques for reducing noise introduced to audio signals by computers have been proposed. For example, systems that provide a number of microphones to detect noise associated with a personal computer, in addition to a microphone external to the computer for capturing sound from the user, have been discussed. Any sound generated by the personal computer that is captured by the external microphone is subtracted from the users voice signal, by subtracting sound captured by microphones internal to the personal computer (or closely associate with the personal computer) from the signal comprising the voice information. Accordingly, such systems rely on a number of microphones.


A flooring product is provided comprising at least one layer including a polymeric binder comprising at least one thermoplastic polyester resin, wherein the polyester resin comprises at least one renewable component. A flooring product is also provided that includes at least one layer comprising filler and at least one thermoplastic, high molecular weight polyester resin. The flooring product may also qualify for at least one point under the LEED System. A composition is also provided that can be melt mixed in low intensity mixers and processed into flooring layers.

The development of resilient flooring products (i.e. non-textile) based on polymers besides polyvinyl chloride (PVC) has been an objective for a long time. For example, acrylic polymers have been disclosed as a binder for flooring products. U.S. Pat. No. 3,575,785 discloses a flooring product comprising poly alkyl methacrylate binder. World Patent Application WO 1994/9415014A1 discloses a floor tile having a binder comprising ethylene butylacrylate copolymer. WO 94/21721 discloses flooring having a wear layer comprised of plasticized acrylic polymers.
Ethylene vinyl acetate (EVA) co-polymers have also been disclosed as a binder for flooring products. For example, U.S. Pat. No. 5,244,942 discloses flooring having an EVA binder and filler. The composition may also contain polypropylene or ethylene-propylene diene monomer (EPDM) polymers as additives. U.S. Pat. Nos. 5,928,754; 6,380,296; 5,407,617; 4,614,556; and EP 0,721,829B1 disclose the use of EVA as a binder in flooring products. U.S. Pat. No. 5,276,082 discloses the use of silane-grafted EVA as a flooring binder.
Functionalized polyolefins such as ethylene acrylic acid co-polymers and their partially neutralized counterparts (ionomers) have also been disclosed as a binder for flooring products. For example, U.S. Pat. No. 4,083,824 discloses a non-vinyl flooring composition comprising (1) a copoly block acrylate comprising at least two C.sub.1 to C.sub.8 linear or branched alkyl acrylates of Mw from about 100,000 to about 300,000 and further characterized by at least two glass transition temperatures, one being above 25.degree. C., the other being below 25.degree. C.; and (2) a random ionic copolymer comprising ethylene and 2.5% to 25% by weight acrylic acid or methacrylic acid partially neutralized by a monovalent or polyvalent metal ion, said ionic copolymer having a melt index of 0.1 to 1000 grams per minute.
U.S. Pat. No. 5,391,612 discloses a flooring product comprising ethylene acrylic acid (EAA) or ethylene methacrylic acid (EMA) copolymers as binders for flooring products.
US Patent Application No. 2005/0048277 discloses a non-vinyl flooring including a binder having a terpolymer comprising ethylene, methyl acrylate and acrylic acid and a copolymer comprising ethylene and methacrylic acid. The non-vinyl flooring may be either a resilient non-vinyl floor tile or a resilient non-vinyl sheet flooring comprising the non-vinyl terpolymer and a copolymer.
U.S. Pat. Nos. 5,728,476; 5,753,767; 5,798,413; 6,921,791; and EP 0,848,037; and WO Application 2004/069920A1 also disclose the use of acid functionalized or ionomer polymers as hinders in flooring, product.
Polyolefin materials have also been disclosed as binders for flooring products. Recent advances in metallocene catalysts have provided new polyolefin materials of interest. Polyolefin binders are disclosed in the following patents: U.S. Pat. Nos. 6,103,803; 6,254,956; 6,356,658; 6,224,804; 5,763,501; 6,287,706; 6,017,586; 5,945,472; 6,187,424; 6,214,924; 5,700,865; 6,617,008; 5,997,782; 5,928,754; 5,824,727; and EP 0,861,951B1.
Aromatic esters and some low molecular weight polyesters have been traditionally used as plasticizers for PVC. U.S. Pat. No. 4,595,626 discloses unsaturated, cross-linkable unsaturated polyesters resins as flooring binders. The end group analysis molecular weight of the polyester is between 600 and 3600. The composition also comprises reactive monomer diluent.
PCT Application WO 95/17568 discloses a wear surface for flooring comprising a thermoset polyester resin and an epoxy or carboxyl-functional acrylic resin and a cross-linking agent. Additionally. U.S. Pat. No. 6,911,263 discloses a wear surface for flooring comprising a composite of PET (polyethylene terephthalate) clear film and a sol gel type surface coating.
Most recently, interest in polylactic acid based polyesters (PLA) has increased since the polymer can be obtained from natural resources and bio-processes. This has given rise to a large number of patents based upon these materials and other alpha-hydroxy acid based polyesters. Due to the polymer structure, these PLA polyesters require the use of plasticizers or other polymer additives for processing and to produce products having acceptable properties. For example, see U.S. Pat. Nos. 6,869,985 and 7,029,750, and US Patent Application No. 2005/0136259 which disclose compositions comprising PLA as a binder component for flooring.
Although there is a still controversy over the manufacture, use, and disposal of polyvinyl chloride, only recently have commercial efforts been made to develop materials and polymers from renewable resources. For example, DuPont's new Sorona fiber comprises a polyester made from terephthalic acid and Bio-produced 1,3-propanediol.
Recently, the US Green Building Council has established the LEED (Leadership in Energy and Environmental Design) system for scoring points for new commercial construction (Table 1). Under the LEED system, flooring can be used to obtain points if it contains 10% by weight or more of post-industrial recycle material.
TABLE 1LEED System for New Commercial ConstructionRatingLEED-NCLEED-EBSystemVersion 2.1Rating SystemVersion 2.0MR Credit5% wt =MR Credit 2.110%4.1(post-consumer +1 point(Post-consumer1 point½ post-industrial)materials), orMR Credit10% wt =20%4.2(post-consumer +(Post-industrial1 point½ post-industrial)materials)MR Credit 65% wt =MR Credit 2.550%1 Point(rapidly renewable1 point(Rapidly renewablebuilding materialsmaterials)and products)NC: New Construction;EB: Existing Building; Minimum % wt for each point. The % for both NC and EB is weight percent. For NC 1 point is granted for at least 5% wt of the total of post-consumer and ½ post-industrial. A second point is granted for at least 10% wt of the total of post-consumer and ½ post-industrial. An additional point is granted for at least 5% wt of rapidly renewable building materials and products.For EB 1 point is granted for at least 10% wt post-consumer materials. A second point is granted for at least 20% wt of post-industrial materials. An additional point is granted for at least 50% wt of rapidly renewable materials.
There has been renewed market interest in giving preference to "greener" flooring, products based upon this LEED System. The use of renewable materials is of high interest.
There continues to be a need for flooring products having a polymeric binder that comprises components obtained from renewable resources. Additionally, there is a need for such a new binder system to be compatible with existing processes and equipment currently utilized for vinyl flooring manufacturing.