Abstract: In the treatment of semiconductor slices, in particular silicon slices, w aqueous solutions containing hydrofluoric acid, a contamination of the slice surface with particles which interfere with the subsequent processes has been observed. This increase in particles can be markedly decreased by additionally adding to the solutions, organic ring molecules capable of forming inclusion compounds, such as, for instance, cyclodextrins, and/or acids with pKa below 3.14 which are incapable of oxidizing the semiconductor material. The actual treatment can be carried out in the usual way, for example, in immersion baths.

Abstract: A high-intensity magnetic separator for separating paramagnetic particles from non-magnetic particles comprises a rotor including a shaft and a stack of alternating ring-shaped pole pieces and permanent magnets arranged on the shaft, the pole pieces and the permanent magnets having substantially equal diameters. To increase the service life of the rotor without noticeably reducing its performance, the permanent magnet is peripherally covered by a layer of ceramic material having a thickness of less than 50 .mu.m.

Abstract: A process for removing contaminants, particularly dopant, from halosilane-containing carrier gases, such as those which are produced in the production of high-purity silicon. The process of the invention is perferably carried out with aid of zeolites which has a low proportion of aluminum and are used in the anhydrous state by bringing the zeolites into contact with the carrier gases. Zeolites, after use, can be regenerated and re-used by increasing the temperature and/or decreasing the pressure of the procedure.

Abstract: A powdery coating glass material essentially consists of V.sub.2 O.sub.5 5-35 wt. %, ZnO 33-60 wt. %, B.sub.2 O.sub.3 3-25 wt. %, SiO.sub.2 1-15 wt. %, Al.sub.2 O.sub.3 0-5 wt. %, and at least one element 2-20 wt. % selected from the group consisting of MgO, CaO, SrO, and BaO, which coating glass material has a softening point of 600.degree. C. or less. A coating glass composition is prepared by the above powdery coating glass material or a coating glass paste for use in a thick-film technique which contains the above powdery coating glass material. The prepared coating glass composition has a thermal expansion coefficient ranging from 55.times.10.sup.-7 /.degree.C. to 75.times.10.sup.-7 /.degree.C.

Abstract: Silicon wafers can be provided with a hydrophilic surface and/or freed of hering cement residues originating from the polishing operation with the aid of solutions adjusted to a pH of 8 to 14 with the aid of alkali-metal or alkaline-earth-metal compounds and containing hydrogen peroxide. These processes can even be carried out at room temperature and are remarkable for their low chemical consumption and easy manageability.

Abstract: A ballast tamping unit for tamping ballast under two successive ties comprises a vertically adjustable tamping tool carrier and a set of two pairs of opposed vibratory and reciprocable tamping tools mounted on the tamping tool carrier, the pairs of tamping tools being so spaced from each other that two adjacent tamping tools of the pairs may be immersed in the crib between two successive ties and two remote tamping tools of the pairs may be immersed in respective cribs adjacent the successive ties.

Abstract: A baking or roasting oven is provided with a transfer apparatus by which the pieces of edible material which is to be roasted, such as slices of white bread, soft wafers, etc., are fed into the oven and the roasted toasts are removed from the oven. The oven comprises an endless chain of hinged tongs, which can be opened and closed and are adapted to hold the pieces of edible material which are to be roasted. The chain of tongs moves in the oven in two superimposed planes. A transfer station is provided adjacent to the upper plane in which the upper course of the chain of tongs extends. The tongs move in an open position through that transfer station, which contains two sets of drums, which are closely spaced one behind the other in the direction of travel of the upper course of the chain of tongs and are disposed above the bottom plates of the open tongs of said upper course.

Abstract: The technical problem is to reduce the operating noise of such a piston. It is solved by means of a piston having the following dimensions: a) A=(0.45-0.65) D; b) H=(0.25-0.4) D; c) A=(0.3-0.4) D; d) A greater than or equal to B; e) T=(0.45-0.8) D; f) the piston ribs between the annular grooves (2, 3, 4) and the rod region with a very narrow operating clearance have, in the case of a hot operating piston, approximately the same clearance in relation to the cylinder operating path. An additional improvement consists in inserting an annular jacket in the piston head in the radial region behind the annular grooves, said jacket consisting of a material having a thermal expension factor less than that of the basic piston material. In a hot operating internal combustion engine, the piston has, in the region of the ribs, a clearance which, in the direction pressure/counter-pressure reaches approximately only 3-5 times the clearance in the very narrow clearance region of the piston rod.

Abstract: A self-propelled machine for continuously laying an overhead line extending above a track and attached to pylons spaced alongside the track, which comprises machine frame movable along the track in an operating direction, a power-driven, vertically and laterally adjustable work platform mounted on the machine frame for an operator assigned to attaching the overhead line to the pylons, a storage drum mounted on the machine frame, a length of the catenary and/or the contact wire of the overhead line being reeled on the storage drum and the drum being rotatable at a pay-out speed for unreeling the catenary and/or the contact wire, and a drive control for adjusting the moving speed of the machine frame in response to the pay-out speed of the catenary and/or the contact wire.

Abstract: A device for forming a leno edge has two reciprocally operated weaving shafts. There is a thread guiding element mounted on one weaving shaft. A needle holder has two parallel substantially U-shaped plastic frame rails arranged on the other weaving shaft, and each needle holder supports a thread guiding element. Each of the frame rails has a replaceable magnetic metal rail insert on its side facing the thread guiding element.

Abstract: A water treatment module (14) has a sedimentation compartment (20), into which water is introduced under high pressure. A filter or microsieve (1) can be provided upstream of the sedimentation compartment (20). Above the sedimentation compartment (20) there is located a flooded first fixed bed reactor (22) for microbiological denitrification, which is flowed through from below. The water travels by way of an overflow device (34) and a sprinkler system (36) through which dissolved nitrogen is stripped and oxygen enrichment from the air occurs, into a second fixed bed reactor (38) for microbiological denitrification. This is constructed as a drip device, and is flowed through by air in a chimney-like fashion. Below the second fixed bed reactor (38) is located a catch basin (44) with a drain (54).

Abstract: A folding apparatus for zigzag folding a paper web with a cylinder driven in rotation alternately in one direction and the other. Two folding rollers are biased against the cylinder. A return stop is provided in the end region of the paper web feed. Two jointly pivotal guide members having guide rails arranged in the manner of a rake with free ends being directed towards one another are located upstream of the cylinder. In the lower end position, the guide rails of the upper guide member project into the built-up space defined between the folding rollers and the rotatable cylinder. The upper guide member, together with the lower folding roller, delimit a guide passage for the paper web. In the upper end position, the guide passage for the paper web is formed by the upper folding roller and the guide rails of the lower guide member.

Abstract: A mobile machine for clearing and planing ballast comprises a machine frame, undercarriages supporting the machine frame for mobility on the railroad track, at least one vertically and transversely adjustable ballast clearing tool connected to the machine frame for clearing ballast laterally outwardly of a respective rail and for planing the ballast upon vertical and transverse adjustment of the tool, the tool being longitudinally adjustably mounted on the machine frame for adjustment in the direction of the railroad track supported by the ballast, and drives connected to the tool for vertically, transversely and longitudinally adjusting the tool.

Abstract: A connecting arrangement for fixing a ski boot to a ski comprises a supporting element having thereon coupling devices in the form of joins, for gripping the ski boot. The supporting element is coupled to the ski by means of a mounting device. The mounting device may comprise two mounting parts which are mutually adjustable in a longitudinal plane extending perpendicularly to the upper part of the ski and substantially parallel to the longitudinal direction of the ski, or the mounting device may be deformable in the longitudinal plane mentioned above. Deformations of the ski, when in use, relative to the boot are thereby taken up.

Abstract: A foot loop for a windsurfing board comprises a loop strip, which arches between two holders, which are adapted to be secured to the top surface of the board at spaced apart locations. The strip is adjustable to change the length of its arched portion and is preferably provided with upholstery. To provide a foot loop which can easily be manipulated and can exactly be adapted to the foot, at least one of the holders comprises an eyelet and the strip and disposed adjacent to said one holder is constituted by a freely terminating strap, which is threaded through said eyelet and is folded about said one holder and is detachably fixed in any of different positions to the top surface of the loop strip or of its upholstery in the arched portion of the loop.

Abstract: A method for the automatic operation of a centrifugal drier comprising a rotary screening basket having a cylindrical wall and which is operated cyclically in successive cycles, each cycle comprising the steps of rotating the basket to generate a centrifugal force, charging a product to be dried into the rotating basket through an open valve, the centrifugal force causing the product to form a layer of increasing thickness along the cylindrical wall, closing the valve to discontinue charging the product when the layer thickness has attained a first control value lower than that of the layer thickness corresponding to an imposed value of the charge in the basket, then measuring the maximum thickness of the layer, comparing said measured maximum layer thickness with a second control value corresponding to said imposed value of the charge in the basket, and generating a new value for the first control value as a function of the difference between the measured maximum layer thickness and the second control value.

Abstract: An elastic body apparatus includes a pneumatic pressure sealing member formed of a hollow flexible material and sealing therein a high pressure pneumatic gas, a movable member driven by an external force against the pressure of the pneumatic pressure sealing member, a fixed shell enveloping a fixed portion of the pneumatic pressure sealing member, and an elastic shell having plate spring portions for applying a spring force in the same direction as the pressing direction of the pneumatic pressure sealing member to the movable member, and disposed at a position enveloping a displacing portion of the pneumatic pressure sealing member. The elastic shell serves as a shell and a spring body, and even if the pressure of the pneumatic pressure sealing member is increased, the pneumatic pressure sealing member is prevented from being deformed in excess of a normal level, and the pressure is transmitted to the movable member through the pneumatic pressure sealing member.

Abstract: The invention relates to a process for the preparation of a high-purity, thermally stable catalyst carrier based on aluminosilicate with 0.5 to 50% by weight SiO.sub.2 by mixing an aluminum compound with a silicic acid compound in an aqueous medium, and subsequently drying or calcining the product obtained. The aluminum component used is a C.sub.2 to C.sub.20+ aluminum alkoxide hydrolyzed with water and purified by means of ion exchangers. Simultaneously or subsequently orthosilicic acid purified by means of ion exchangers is added to the aluminum compound.

Abstract: A caster with an installation base comprises a shaft to be secured to a leg or bottom of a machine or instrument, a frame rotatably mounted on the shaft, movement wheels supported on the frame, an installation base arranged unrotatably and vertically movable on the frame, and a handle member for vertically moving the installation base. The frame comprises a connecting portion rotatably mounted on the shaft and an axle supporting portion for supporting an axle of the movement wheels. The installation base comprises a first portion arranged in the periphery of the connecting portion of the frame and formed in the outer peripheral surface with an external thread and a second portion positioned below the shaft to come into contact with an installation surface.