Abstract: The present invention provides for the production of a single frit, dental porcelain, glass-ceramic containing small, uniformly dispersed, single leucite crystals of ellipsoidal habit and very uniform size.

Abstract: An indium phosphide substrate for semiconductor devices is obtained as follows. In order to have the direction of growth of the crystal in the <100> orientation, a seed crystal having a specified cross-sectional area ratio with the crystal body is placed at the lower end of a growth container. The growth container housing the seed crystal, indium phosphide raw material, dopant, and boron oxide is placed in a crystal growth chamber. The temperature is raised to at or above the melting point of indium phosphide. After melting the boron oxide, indium phosphide raw material, and dopant, the temperature of the growth container is lowered in order to obtain an indium phosphide monocrystal having a low dislocation density and a uniform dopant concentration on the wafer as well as in the depth direction.

Abstract: The present invention relates to new crystalline molecular sieve SSZ-74 prepared using a hexamethylene-1,6-bis-(N-methyl-N-pyrrolidinium)dication as a structure-directing agent, and its use in catalysts for synthesizing amines.

Abstract: The invention is directed to a process and method for forming synthetic hydroxysodalite from nepheline and feldspar and/or nepheline syenite. A caustic material such as a solution of sodium hydroxide is combined with the nepheline and feldspar and/or nepheline syenite to form the synthetic hydroxysodalite.

Abstract: A nitride semiconductor substrate having properties preferable for the manufacture of various nitride semiconductor devices is made available, by specifying or controlling the local variation in the off-axis angle of the principal surface of the nitride semiconductor substrate. In a nitride semiconductor single-crystal wafer having a flat principal surface, the crystallographic plane orientation of the principal surface of the nitride semiconductor single-crystal wafer varies locally within a predetermined angular range.

Abstract: The present invention relates to silicon feedstock for producing directionally solidified silicon ingots, thin sheets and ribbons for the production of silicon wafers for PV solar cells where the silicon feedstock contains between 0.2 and 10 ppma boron and between 0.1 and 10 ppma phosphorus distributed in the material. The invention further relates to directionally solidified silicon ingot or thin silicon sheet or ribbon for making wafers for solar cells containing between 0.2 ppma and 10 ppma boron and between 0.1 ppma and 10 ppma phosphorus distributed in the ingot, said silicon ingot having a type change from p-type to n-type or from n-type to p-type at a position between 40 and 99% of the ingot height or sheet or ribbon thickness and having a resistivity profile described by an exponential curve having a starting value between 0.4 and 10 ohm cm and where the resistivity value increases towards the type change point.

Abstract: A method for growing a silicon single crystal ingot by a Czochralski method, which is capable of providing silicon wafers having very uniform in-plane quality and which results in improvement of semiconductor device yield. A method is provided for producing a silicon single crystal ingot by a Czochralski method, wherein when convection of a silicon melt is divided into a core cell and an outer cell, the silicon single crystal ingot is grown under the condition that the maximal horizontal direction width of the core cell is 30 to 60% of a surface radius of the silicon melt. In one embodiment the silicon single crystal ingot is grown under the condition that the maximal vertical direction depth of the core cell is equal to or more than 50% of the maximal depth of the silicon melt.

Abstract: The invention involves a process for production of macrostructures of a microporous material. The process is characterized by the fact that seeds formed in or introduced by ion exchange or adsorption to a porous organic ion exchanger with the desired size, shape and porosity are made to grow and form a continuous structure by further deposition of inorganic material from a synthesis solution under hydrothermal conditions. The organic ion exchanger can be eliminated by chemical destruction or dissolution and, in so doing, leaves behind an inorganic microporous structure with the size and shape of the employed organic ion exchanger.

Abstract: Disclosed is a transition-metal chalcogenide crystal having a topological configuration/structure. A micro-droplet of a chalcogen element, such as S, Se or Te, is condensed and circulated in suspended form in an atmosphere containing a Group IVb, Vb or VI transition metal element, such as Nb, Ta, Zr, Ti, Hf or W, together with the chalcogen element. Then, micro-whiskers of a transition metal chalcogenide formed in the atmosphere are attached onto a surface of the chalcogen-element micro-droplet by the action of a surface tension of the micro-droplet, and grown as a loop-shaped crystal wound around the surface of the micro-droplet to obtain a loop-shaped crystal having a twist of 0, ? or 2?. The crystal has a ribbon-like open or closed loop configuration. The transition-metal chalcogenide crystal with the topological loop-shaped microstructure can exhibit original properties peculiar to each transition-metal chalcogenide, and has applicability, for example, to a quantum device, such as SQUID.

Abstract: In this method for growing a silicon single crystal, an ambient gas where a single crystal is grown contains a gas hydrogen-containing substance, and a silicon single crystal is grown at a pull rate to form a dislocation cluster defect occurrence region at least in a portion of a radial cross section of said silicon single crystal and at a pull rate which is slower than that to form an laser scattering tomography defect occurrence region, according to the Czochralski method. This silicon wafer is sampled from a straight body of the silicon single crystal grown using said method for growing a silicon single crystal, and the LPD density of LPD of 0.09 ?m or greater in the surface after 10 times of repetitions of the SC-1 cleaning is 0.1/cm2 or less.

Abstract: This silicon wafer is obtained from a silicon single crystal grown by the CZ method in a hydrogen-containing inert gas atmosphere, and is a completely grown-in defect-free wafer containing no COPs or dislocation clusters throughout the wafer in the thickness and radial directions thereof, and all the portions consist essentially of an interstitial rich region. This method for growing silicon single crystals includes pulling a silicon single crystal in a hydrogen-containing inert gas atmosphere so as to expand the range of the pull rate for the PI region, wherein the pulling of the silicon single crystal is conducted at a pull rate within this expanded range of the pull rate for the PI region so as to grow a body portion that is an interstitial rich region.

Abstract: A silicon wafer for an IGBT is produced by forming an ingot having an interstitial oxygen concentration [Oi] of not more than 7.0×1017 atoms/cm3 by the Czochralski method; doping phosphorus in the ingot by neutron beam irradiation to the ingot; slicing a wafer from the ingot; performing annealing of the wafer in an oxidizing atmosphere containing at least oxygen at a temperature satisfying a predetermined formula; and forming a polysilicon layer or a strained layer on one side of the wafer.

Abstract: A mesoporous material is described. It includes a network of interconnected pores within an L3 phase structure. The pores include pore walls of a silicate material functionalized with at least one metal cation—usually a transition metal. Articles which include the mesoporous material are also disclosed, along with methods for making the mesoporous material.

Abstract: The present invention is a method for producing a single crystal in accordance with Czochralski method by flowing an inert gas downward in a chamber 1 of a single crystal-pulling apparatus 11 and surrounding a single crystal 3 pulled from a raw material melt 2 with a gas flow-guide cylinder 4, wherein when a single crystal within N region outside OSF region generated in a ring shape in the radial direction of the single crystal is pulled, the single crystal within N region is pulled in a condition that flow amount of the inert gas between the single crystal and the gas flow-guide cylinder is 0.6 D(L/min) or more and pressure in the chamber is 0.6 D(hPa) or less, in which D (mm) is a diameter of the single crystal to be pulled. It is preferable that there is used the gas flow-guide cylinder that Fe concentration is 0.05 ppm or less, at least, in a surface thereof.

Abstract: A useable particulate nepheline syenite having a grain size to provide an Einlehner Abrasive Value of less than about 100 is described. The particulate nepheline syenite is generally free from agglomeration and moisture free. At least 99% of the nepheline syenite particles have a size less than 10 microns. In practice, the nepheline syenite grain size is less than about 5 microns and the distribution profile of the particulate system is generally 4-5 microns.

Abstract: A semiconductive GaAs wafer has a diameter of 4 inches or more, and an in-wafer plane dislocation density of 30,000/cm2 or more and 100,000/cm2 or less. A semiconductive GaAs wafer is made by growing a GaAs single crystal under a temperature gradient of 20° C./cm or more and 150° C./cm or less formed in the crystal so that the semiconductive GaAs wafer has an in-wafer plane dislocation density of 30,000/cm2 or more and 100,000/cm2 or less.

Abstract: The present invention provides an annealed wafer which has a wafer surface layer serving as a device fabricating region and having an excellent oxide film dielectric breakdown characteristic, and a wafer bulk layer in which oxide precipitates are present at a high density at the stage before the wafer is loaded into the device fabrication processes to give an excellent IG capability, and a method for manufacturing the annealed wafer. The present invention is directed to an annealed wafer obtained by performing heat treatment on a silicon wafer manufactured from a silicon single crystal grown by the Czochralski method, wherein a good chip yield of an oxide film dielectric breakdown characteristic in a region having at least a depth of up to 5 ?m from a wafer surface is 95% or more, and a density of oxide precipitates detectable in the wafer bulk and each having a size not smaller than a size showing a gettering capability is not less than 1×109/cm3.

Abstract: Methods for the removal of lead from a metal silicate during the process of manufacturing of such a material are provided. With the reliance upon lower cost starting silicon dioxide starting materials that are known to exhibit elevated amounts of heavy metal therein for the purpose of producing metal silicates (such as sodium silicate, as one example), it has been realized that removal of significant amounts of such heavy metals is necessary to comply with certain regulatory requirements in order to provide a finished material that exhibits the same low level of heavy metal contamination as compared with finished materials that are made from more expensive, purer starting silicon dioxides. Two general methods may be followed for such decontamination purposes. One entails the introduction of a calcium phosphate material, such as dicalcium phosphate, tricalcium phosphate, and/or hydroxyapatite, to a formed metal silicate solution but prior to filtering.

Abstract: A metalloaluminosilicate composition includes an aluminosilicate composition having an aluminosilicate framework and containing at least one metal, wherein a substantial portion of the metal is incorporated into the aluminosilicate framework. A higher concentration of the metal is incorporated into the framework of the catalyst than is present at the surface of the catalyst.

Abstract: A high quality single crystal wafer of SiC is disclosed. The wafer has a diameter of at least about 3 inches (75 mm) and at least one continuous square inch (6.25 cm2) of surface area that has a basal plane dislocation volume density of less than about 500 cm?2 for a 4 degree off-axis wafer.

Abstract: A solar cell is produced by dipping a multicrystalline silicon substrate 28 in a solution 24 containing silicon, growing a silicon layer on the substrate 28 while decreasing with time the temperature drop rate of the solution during the dipping of the substrate in the solution, and forming a pn junction in the silicon layer. Thereby, there is provided a silicon layer production method that can form a thick layer while restraining the degree of roughness, whereby a low-cost, multicrystalline-silicon solar cell production method is provided that realizes both a large current and a high FF.

Abstract: The present invention is directed to a method of making large diameter metal fluoride sungle crystals that can be used in optical lithograpby systems, for example, excimer laser that operate below 200 nm. In addition, the invention is directed to metal fluoride single crystals suitable for use in such lithographic ststems, such fluoride crystals having a internal transmission of ?99.9% at 193 nm and ?99.0% at 157 nm.

Abstract: AlGaInN single-crystal wafer with alleviated cracking and improved utilization rate and cost effectiveness. A hexagonal AlxGayIn1?(x+y)N(0<x?1, 0?y<1, x+y?1) single-crystal wafer, characterized in that the wafer has a thickness T(cm) and a principal face with a surface area S(cm2), the area S and thickness T satisfying the conditions S?10 cm2 and 0.006S?T?0.002S.

Abstract: A method to produce an anti-swelling mica having following steps: mixing powdery mica with an alkaline compound to form a mixture; heating the mixture at a temperature between 150° C.˜230° C. for lasting 30 minutes to make metal ions out of the alkaline compound to diffuse into the mica homogeneously; using water to reduce temperature of the mixture so as to form an alkaline solution; separating the powdery mica from the alkaline solution to obtain a solid mica; neutralizing excessive alkaline compound adhering to the solid mica by an acid solution that is diluted by cold water and the mica anti-swells after adjusting pH of the solid mica to less than 7.0; and diluting the acid solution again by adding water and separating the solid mica from diluted acid solution to obtain a production—anti-swelling mica.

Abstract: A high resistivity p type silicon wafer with a resistivity of 100 ?cm or more, in the vicinity of the surface being formed denuded zone, wherein when a heat treatment in the device fabrication process is performed, a p/n type conversion layer due to thermal donor generation is located at a depth to be brought into contact with neither any device active region nor depletion layer region formed in contact therewith or at a depth more than 8 ?m from the surface, and a method for fabricating the same. The high resistivity silicon wafer can cause the influence of thermal donors to disappear without reducing the soluble oxygen concentration in the wafer, whereby even if various heat treatments are performed in the device fabrication process, devices such as CMOS that offer superior characteristics can be fabricated. The wafer has wide application as a substrate for a high-frequency integrated circuit device.

Abstract: Methods for the removal of lead from a metal silicate during the process of manufacturing of such a material are provided. With the reliance upon lower cost starting silicon dioxide starting materials that are known to exhibit elevated amounts of heavy metal therein for the purpose of producing metal silicates (such as sodium silicate, as one example), it has been realized that removal of significant amounts of such heavy metals is necessary to comply with certain regulatory requirements in order to provide a finished material that exhibits the same low level of heavy metal contamination as compared with finished materials that are made from more expensive, purer starting silicon dioxides. Two general methods may be followed for such decontamination purposes. One entails the introduction of a calcium phosphate material, such as dicalcium phosphate, tricalcium phosphate, and/or hydroxyapatite, to a formed metal silicate solution but prior to filtering.

Abstract: A process for the preparation of mesostructured organofunctional silica and silica-alumina compositions using a hydrolyzable organosilane compound is described. The process uses a water soluble silicate to form the compositions, which have hexagonal, wormhole or foam mesostructures. The compositions are useful for catalytic and sorption applications.

Abstract: A method of method of making a formed ceramic body, comprising casting or jiggering a composition comprising a mullite-rich calcined kaolin obtained from a hydrous kaolin. Also provided is a method of modifying/increasing the casting rate of a formed body formulation comprising hydrous kaolin, the method comprising substituting at least 10% of the hydrous kaolin in the formulation with a mullite-rich calcined kaolin. Also provided is a ceramic body filter cake comprising a mullite-rich calcined kaolin, wherein the mullite-rich calcined kaolin is obtained from a hydrous kaolin and a method of modifying/increasing the filtration rate of a ceramic body filter cake comprising hydrous kaolin, the method comprising substituting at least 10% of the hydrous kaolin in the ceramic body filter cake with a mullite-rich partially calcined kaolin.

Abstract: Mesoporous hexagonal, cubic, lamellar, wormhole, or cellular foam aluminosilicates, gallosilicates and titanosilicates derived from protozeolitic seeds using an ionic structure directing agent are described. The silicon and aluminum, gallium or titanium centers in the structures are stable so that the framework of the structure does not collapse when heated in the presence of water or water vapor (steam). The steam stable compositions can be used as catalysts for hydrocarbon conversions, including the fluidized bed catalytic cracking and the hydrocracking of petroleum oils, and other reactions of organic compounds.

Abstract: Process for the manufacture of high-purity alumino-silicates which are dispersible in aqueous and/or aqueous-acidic media by hydrolysis of aluminum compounds and organosilicon compounds.

Abstract: Precipitated silica or silicates, obtainable by acid precipitation of aqueous silicate solutions while maintaining a constant alkali number of at least 1.

Abstract: There is provided macrostructures of porous inorganic material which can have controlled size, shape, and/or porosity and a process for preparing the macrostructures. The macrostructures comprise a three-dimension network of particles of porous inorganic materials. The process for preparing the macrostructures involves forming an admixture containing a porous organic ion exchanger and a synthesis mixture capable of forming the porous inorganic material and then converting the synthesis mixture to the porous inorganic material. After formation of the composite material, the porous organic ion exchanger can be removed from the composite material to obtain the macrostructures.

Abstract: The present invention relates to an icosahedral, quasicrystalline compound or compound present in the form of an approximant having the nominal composition: TivCrwAlxSiyOz, in which v=60-65; w=25-30; x=0-6; Y=8-15; z=8-20; and in which the atom percent of oxygen is in the range of between 8 and 15%, and that of aluminum in the range of between 2 to 5%. Due to their layered structure and ceramic intermediate layers, compounds of this type exhibit excellent properties, in particular for use as coatings for gas turbine components, such as for example, rotor blades or guide vanes.

Abstract: Highly ordered mesoporous silica molecular materials are prepared using sodium silicate as a silica source, sulfuric acid and nonionic poly(alkylene oxide) surfactants or nonionic amphiphilic bloc copolymers as structure-directing agents. The mesoporous silica materials obtained have hexagonal and cubic structures, uniform pore size and high surface areas.

Abstract: A metalloaluminosilicate composition includes an aluminosilicate composition having an aluminosilicate framework and containing at least one metal, wherein a substantial portion of the metal is incorporated into the aluminosilicate framework. A higher concentration of the metal is incorporated into the framework of the catalyst than is present at the surface of the catalyst.

Abstract: The invention concerns a novel crystalline solid UVL-1 which has an X ray diffraction diagram containing at least the following characteristic peaks: dhkl (A) 2theta (°) I/I0 11.69 7.55 mw to vs 7.50 11.79 vw to w 5.76 15.36 w to mw 3.70 24.00 m to s 3.57 24.91 s 3.36 26.49 vs 3.14 28.48 w to mw 2.50 35.88 vw 2.41 37.30 vw and with a chemical composition, expressed as the anhydrous compound, in terms of moles of oxide: (XO2):(Y2O3)m:(Z2/nO)p in which: X represents at least one tetravalent element selected from the group formed by Si, Ge; Y represents at least one trivalent element selected from Al, B, Cr, Ga; Z represents at least one cation with valency n; and in which: n is in the range 2 to 4, m is in the range 0 to 0.2, preferably in the range 0 to 0.05, and p is in the range 0 to 0.2, preferably in the range 0 to 0.05.

Abstract: The invention concerns a crystalline solid, designated ITQ-31, which has the X ray diffraction diagram given below. Said solid has a chemical composition, expressed as the anhydrous base in terms of moles of oxide, defined by the general formula XO2: mYO2:pZ2O3:qR:sF, in which R represents an organic nitrogen-containing template, X represents one or more tetravalent elements other than germanium, Y represents germanium, Z represents at least one trivalent element and F is fluorine.

Abstract: Disclosed is a method for the manufacture of silicoaluminophosphate (SAPO) and/or aluminophosphate (ALPO) molecular sieves. The method includes maintaining the slurry of the as crystallized molecular sieve under substantially static conditions when stored after substantially complete crystallization and prior to recovery of the product.

Abstract: This invention relates to a new composition of high surface area materials suitable for adsorption of both organic and inorganic species and as a component of catalysts useful for the transformation of hydrocarbons into a variety of products. These materials are composed by mesoporous spherical particles that have large sorption capacity, as demonstrated by the uptake of nitrogen at 78 K having a diameter of 0.1 to 1.0 microns, a mean pore diameter of 2.0 nm to 4.0 nm, a surface area of 750 to 1050 m2/g and a mean pore volume of 0.75 to 1.0 ml/g. The typical inner structure is composed of nanotubes having diameters around 3.5 nm aligned along the radius of the spherical particles, with surface areas around 1,000 m2/g, depending on the surfactant (C16H33N(CH3)3Br) to co-solvent (CnH2n+1OH, where n=2,3, or CH3COCH3) molar ratio.

Abstract: Colloidal crystalline molecular sieve seeds are used in phosphorus-containing crystalline molecular sieve manufacture. Certain of the products have enhanced utility in oxygenate conversions.

Abstract: In the method for growing large-volume monocrystals crystal raw material is heated in a melting vessel with heating elements to a temperature above its melting point until a melt is formed. A monocrystal is then formed on the bottom of the melting vessel by lowering the temperature at least to the crystallization point. A solid/liquid phase boundary is formed between the monocrystal and the melt. The monocrystal grows towards the melt surface in a direction that is perpendicular to the phase boundary. A vertical axial temperature gradient is produced and maintained between the bottom of the melting vessel and its upper opening and heat inflow and/or heat outflow through side walls of the melting vessel is prevented, so that the solid/liquid phase boundary has a curvature radius of at least one meter. A crystal-growing device for performing this process is also described.

Abstract: The present invention relates to a silicoaluminophosphate molecular sieve comprising at least one intergrown phase of molecular sieves having AEI and CHA framework types, wherein said intergrown phase has an AEI/CHA ratio of from about 5/95 to 40/60 as determined by DIFFaX analysis, using the powder X-ray diffraction pattern of a calcined sample of said silicoaluminophosphate molecular sieve. It also relates to methods for its preparation and to its use in the catalytic conversion of methanol to olefins.

Abstract: There is provided macrostructures of porous inorganic material which can have controlled size, shape, and/or porosity and a process for preparing the macrostructures. The macrostructures comprise a three-dimension network of particles of porous inorganic materials. The process for preparing the macrostructures involves forming an admixture containing a porous organic ion exchanger and a synthesis mixture capable of forming a porous inorganic material and then converting the synthesis mixture to a solid porous inorganic material. After formation of the composite material, the porous organic ion exchanger can be removed from the composite material to obtain the macrostructures, either before or after the porous inorganic material is hydrothermally treated with a structure directing agent to convert at least a portion of such porous inorganic material to a crystalline molecular sieve composition. The resulting macrostructure is composed of particles of the crystalline molecular sieve composition.

Abstract: There is provided macrostructures of porous inorganic material which can have controlled size, shape, and/or porosity and a process for preparing the macrostructures. The macrostructures comprise a three-dimension network of particles of porous inorganic materials. The process for preparing the macrostructures involves forming an admixture containing a porous organic ion exchanger and a synthesis mixture capable of forming the porous inorganic material and then converting the synthesis mixture to the porous inorganic material. After formation of the composite material, the porous organic ion exchanger can be removed from the composite material to obtain the macrostructures.

Abstract: The present invention provides a silicon single crystal wafer having a diameter of 300 mm or more and having a defect-free layer containing no COP for a depth of 3 ?m or more from a surface and a method for producing a silicon single crystal, wherein, when a silicon single crystal having a diameter of 300 mm or more is pulled with nitrogen doping by the CZ method, the crystal is grown with a value of V/G [mm2/K·min] of 0.17 or less, where V [mm/min] is a pulling rate, and G [K/mm] is an average of temperature gradient in the crystal along a pulling axis from the melting point of silicon to 1400° C. Thus, there are established conditions for pulling a silicon single crystal and conditions for heat treatment of wafer for obtaining a silicon single crystal wafer having a defect-free layer free from COP for a sufficient depth of the surface layer by pulling a silicon single crystal having a diameter of 300 mm or more, processing the crystal into wafers and subjecting the wafers to the heat treatment.

Abstract: Selected smectites may be synthesized from a wide variety of components. Morphology, purity, size, and/or shape of the selected smectite may be controlled by mixing the clay smectite formatives, and selectively controlling the pH during mixing. The selected smectites may be used in any applications in which naturally occurring smectite may be used. The selected smectite may also be formulated into an organoclay.

Abstract: A refined SiC single crystal that includes a small number of defects is provided as follows. At a first growth step, a first seed crystal is formed from a crude SiC single crystal, and a first grown crystal is formed on a first growth surface, which is a plane having an inclination of 20 degrees or smaller from a {1-100} plane or an inclination of 20 degrees or smaller from a {11-20} plane. At an intermediate growth step, an n growth crystal is formed on an n growth surface, which is a plane having an inclination of 45 to 90 degrees from an (n?1) growth surface and an inclination of 60 to 90 degrees from a {0001} plane. At a final growth step, a final SiC single crystal is formed on a final growth surface, which has an inclination of 20 degrees or smaller from a {0001} plane.

Abstract: Mesoporous hexagonal, cubic, lamellar, wormhole, or cellular foam aluminosilicates, gallosilicates and titanosilicates derived from protozeolitic seeds using an ionic structure directing agent are described. The silicon and aluminum, gallium or titanium centers in the structures are stable so that the framework of the structure does not collapse when heated in the presence of water or water vapor (steam). The steam stable compositions can be used as catalysts for hydrocarbon conversions, including the fluidized bed catalytic cracking and the hydrocracking of petroleum oils, and other reactions of organic compounds.

Abstract: The invention concerns a heat-stable ordered mesoporous or mesostructured material comprising a mineral phase wherein are dispersed particles of nanometric dimension at least partly crystaline, the global crystallinity index of said mesostructured or ordered mesoporous material being less than 10% in volume. The invention also concern a method for obtaining such a material.

Abstract: The invention relates to a device and method for depositing one or more layers onto at least one substrate placed inside a reaction chamber. The layers are deposited while using a liquid or solid starting material for one of the reaction gases utilized, which are fed via a gas admission unit to the reaction chamber where they condense or epitaxially grow on the substrate. The gas admission unit comprises a multitude of buffer volumes in which the reaction gasses enter separate of one another, and exit through closely arranged outlet openings while also being spatially separate of one another. The temperature of reaction gases is moderated while passing through the gas admission unit.