Abstract: A process and system for recovery of gold from an ore having the steps of i) providing the ore containing the gold to be recovered, ii) leaching the ore in an oxidative chloride medium, including a nitrogen species to produce a solution comprising gold; and iii) recovering the gold from the solution. The gold in a preferred embodiment is recovered from refractory and carbonaceous ores.

Abstract: A nail positioning device comprising a main body with specific elasticity and thickness; an insert penetration hole formed on the main body and penetrating vertically from top to bottom of the main body, and parallelly interconnected to an exit through slot, and the exit through slot being interconnected to the periphery of the main body, such that the exit through slot and the insert penetration hole form an open slot; and a low adhesive glue coated on a bottom surface of the main body or the main body being made of a low adhesive material, so that a nail can be positioned appropriately without requiring users to hold the nail by hand before the nail is hammered, so as to provide excellent positioning effect and operation safety, while using the low adhesive glue to be attached onto a construction surface for repeated uses.

Abstract: A convertible driving tool includes a tool handle having a carrier, a tool head having a shank for engaging into a compartment of the carrier, and a latch device includes a shaft engageable through the shank and the carrier, and the shaft includes a catch member for being engaged between the shank and the carrier for selectively latching the shank to the carrier, the catch member of the latch device is disengageble from the shank for allowing the tool head to be easily and quickly and readily attached or coupled to the tool handle and to be disengaged from the tool handle, and for allowing the driving tool head to be easily and quickly and readily changed or replaced with the new ones.

Abstract: A ratchet wrench includes a wrench body having a circular space defined at a head portion of the wrench body, a ratchet with a hollow center placed into the circular space. The ratchet is symmetric to the wrench body. The inner wall of the ratchet has a plurality of first ridges formed thereon. A first recess is formed between each of two adjacent first ridges. Each of the first recesses selectively has a second ridge formed thereon. A second recess is defined on the second ridge. The shape of the second recess is as same as the first recess. In this way, a user can directly alternate the big and small bolts in the ratchet wrench, rather than turn over the wrench to fit the big or small bolt.

Abstract: A tool adapted to install and remove strainer basket assemblies. The tool has a tubular main body that incorporates a means for gripping the upper strainer nut on a strainer basket assembly. The tool also has a moveable shaft that incorporates a means for gripping a strainer basket assembly. The tool is used to assemble a strainer basket assembly by attaching the tool's upper strainer nut gripping means to a upper strainer nut, attaching the tool's strainer basket gripping means to a strainer basket assembly, and applying a force to the tubular main body and an opposing force to the moveable shaft to tighten the upper strainer nut. The tool is used to disassemble and remove a previously installed strainer basket assembly by attaching the tool's upper strainer nut gripping means to an upper strainer nut, attaching the strainer basket gripping means to a strainer basket assembly, and applying a force to the tubular main body and an opposing force to the moveable shaft to loosen the upper strainer nut.

Abstract: A wrench including a handle, an open drive portion, and a closed drive portion is provided. The open drive portion and the closed drive portion are located at two ends of the handle, respectively. The handle includes a first side, a second side, and two recessed structures. The second side is opposite to the first side. The recessed structures are formed on the first side and the second side, respectively. The recessed structures are near the ends of the handle, respectively. Both the open drive portion and the closed drive portion have an abutting plane. Each abutting plane forms an angle with an extending axis of the handle.

Abstract: A clamping structure for a tool is provided. The clamping structure includes a plurality of grooves and an inner surface. The inner surface includes two inclined planes. Two convex arcs are connected to the inclined planes. Two concave arcs are connected to the inclined planes, and a middle salient connects one of the concave arcs to the other of the concave arcs. Wherein, an angle between a hypothesized extension line of one of the inclined planes and a hypothesized central line of one of the grooves is 40 degrees-50 degrees. Whereby, the clamping structure is easy to grip a damaged bolt or a damaged nut.

Abstract: A bit holder assembly for a rotary hand or powered tool, includes a body having a hex shank at its rearward end and a retraction collar slidably disposed on the body. The body has a coaxial hex socket formed therein to allow a tool bit to be inserted thereinto. A coil spring biases the retraction collar forwardly and biases a retaining clip toward the bottom of an angular slot formed in the body. The bit is removed by sliding the retraction collar rearwardly, to compress the coil spring and allow the retaining clip to retract back up the slot. A ring magnet is disposed at the forward end of the retraction collar to magnetize a fastener to retain the fastener to the bit.

Abstract: A method of manufacturing a handle for a personal grooming device includes forming a substrate portion of a first material. The substrate portion has first and second walls forming a channel extending along a long axis of the substrate portion. An insert member is formed separate from the substrate portion and disposed within the channel. A grip portion of a second material is formed on the substrate portion. The second material substantially encases the insert member.

Abstract: For precise alignment of the punch stamps relative to the cutting plates, the respective punch stamp 23 is supported in a floating manner, i.e., in a transversely movable manner, on the head plate 8 associated with the punch stamp. The alignment of the cutting edges of the punch stamp with respect to the cutting edges 49, 50, 51 of the cutting plate 18 is accomplished by at least one stamp guide arrangement 42 that is directly active between the punch stamp 23 and the cutting plate 18 and effects precise relative positioning in a direction transverse to the active cutting edges. The centering elements may extend from the punch stamp 23 through the matrix or cutting plate 18. Alternatively, the centering elements may extend from the cutting plate 18 through the openings of the punch stamp 23 or extend along sliding or positioning surfaces of the punch stamp.

Abstract: A cutting tool has an internal cutting tool fluid delivery system. The cutting tool has a tool body and a fluid delivery head coupled thereto by a solid coupling member with a continuous male thread. The tool body includes a body coupling bore and the head includes a head coupling bore which communicates with the body coupling bore. At least one of the body and head coupling bores includes a circumferentially interrupted female thread which has a longitudinal thread axis and a radial outer thread boundary. The or each coupling bore having the female thread includes a thread passage which extends along the thread axis. In an axial cross section of the female thread, the thread passage extends both inside and outside the radial outer thread boundary.

Abstract: A wafer edge trim blade includes a round blade body and at least one slot formed inward from an outside edge of the round blade body. The at least one slot is configured to remove debris generated during wafer edge trimming using the wafer edge trim blade.

Abstract: A sheet processing apparatus includes a punch portion punching a hole at an end part of a sheet, and a push-out member discharging the sheet by pushing the end part of the sheet where the punch process is performed by the punch portion. The push-out member discharges the sheet at a sheet discharging speed lower than a predetermined speed from the intermediate process tray in accordance with punch process information (i.e., combination of a size and a type of the sheet and number, a shape and a size of holes) that strength of a sheet end part is decreased by the punch process, and is lower than predetermined sheet strength capable of being discharged at the predetermined speed.

Abstract: A saw (100) includes a sawdust collection assembly (2) having a chute (10) made of a material having a stretchability to be shaped responsive to movement of a blade housing (102) into a moveable sawdust path. An upper end (40) of a top portion (6) of the chute (10) is removably and reattachably engaged with a top attachment member (36) mounted to the blade housing (102). A bottom portion (8) of the chute (10) is removably and reattachably engaged with a bottom attachment member (26) mounted to a rear side (106C) of a fence (106) of the saw (100). Two side edges (44, 46) of the top portion (6) are respectively attached by two side tension cords (18) to left and right sides (106B, 106A) of the fence (106). One of the side tension cords (18) can be used with a tension block (20, 28) to form a tensioning system.

Abstract: The invention relates to a guide device (1000) for a blade (322) having a slide (320) for receiving the blade (322) and a slide guide (330) and a glide element 300 between the slide guide (330) and the slide (320). A cooling device (205) is arranged for cooling the glide element (300). According to the invention, the cooling device (205) is designed as at least a closed cooling channel (210) or as an open cooling channel (209) having at least one inlet (215, 216) and one outlet (215, 216) for a cooling medium.

Abstract: An apparatus for cutting fiberglass insulation batting with a rotary blade where an elongate section of fiberglass insulation batting is manually pushed into an inlet of the apparatus whereupon the blade bites into the fiberglass insulation batting and whereupon the elongate now split section of fiberglass insulation batting begins to protrude from the outlet of the apparatus, whereupon the protruding sections of fiberglass insulation batting are manually grabbed and pulled through the apparatus further driving the rotary blade and further cutting the fiberglass insulation batting.

Abstract: A release space (100) is formed in a holding member (47) so as to be disconnected from a back pressure chamber (49) before a blade member (30) cuts a current-carrying member (12), and communicate with the back pressure chamber (49) after the blade member (30) has cut the current-carrying member (12).

Abstract: Equipment for stabilizing rotation of a blade in a circle saw and for staying at the wanted sawing line which equipment comprises the formation devices (1,2); (7,8); (10,11) of a magnetic field in connection with a ferrous metallic circle saw blade (3) and equipment for adjusting the intensity of the mentioned magnetic field, such as a sensor (14) that measures the sideway position of a control center (13) and a circular blade (3). Of the formation devices of the magnetic field metallic parts (1); (7) or (10) that direct at least magnetic flux in the last resort to the circle saw blade (3) or part of them are located in relation to the circle saw blade (3) outside its toothing (4), at the location of the teeth essentially to the level of the circle saw blade (3).

Abstract: A tool for preparing a cable for connectorization. The tool has a portion for stripping a cable jacket and another portion for cutting fibrous strength elements, such as aramid strength elements, relative to the exposed fiber. The strength element cutting portion includes a blade enclosed in a cover that also serves as a handle for the tool. The cover also has a stop edge to ensure that a desired excess length of the strength element remains after cutting the strength element. The excess strength element length can then be used to connectorize the cable.

Abstract: A guitar neck joint routing system. The system includes a probe and router assembly comprising a gantry, a probe, and a plurality of routers, and a guitar neck and body nest comprising clamps and vacuum grips for holding a guitar neck and guitar body in place for taking measurements and routing a dovetail joint.

Abstract: A tensioner for a string on a stringed musical instrument is provided. The tensioner can include an elongated body, at least two spring modulation members, a spring modulation support, and at least one spring. Each of the spring modulation members have a first portion pivotably attached to a portion of the elongated body. The spring modulation support is pivotably attached to a second portion of each of the spring modulation members. The spring is interposed between the elongated body and the spring modulation support.

Abstract: A guitar slide holder for supporting a guitar slide so that the guitar slide may be secured when not in use and then easily removed and positioned on a guitarist's finger. The guitar slide holder can be releasably attached to a guitar strap so as to be easily accessed by the guitarist. Alternatively, the guitar slide holder can be coupled to a microphone stand or similar object so as to assist in locating the guitar slide holder in a convenient position near the guitarist. The guitar slide holder improves the storage, access, and finger positioning of the guitar slide so as to provide the guitarist with the ability to easily transition between using a guitar slide and not.

Abstract: The present disclosure relates to a system and method for visualization of music and other sounds. In one embodiment, the twelve notes of an octave are labeled. When notes are played, the intervals between the notes are visualized by displaying a line between the labels corresponding to the note labels. In some embodiments, the lines representing the intervals are color coded with a different color for each of the six intervals.

Abstract: An apparatus for creating a musical composition comprising an audio interface, and audio converter module, and a multi-track compositor module is disclosed. The audio interface operably receives audio from an audio input device and outputting audio to an audio output device. The audio converter module is operably connected to the audio interface to convert audio received via the audio interface into an audio track having one or more partitions. The multi-track compositor module is configured to receive a first audio track and a second audio track and automatically score each partition of the first and second audio tracks based on one or more criteria. The multi-track compositor module is then configured to construct a third audio track from the partitions of the first and second audio tracks based on the scores for each partition. A method is also provided.

Abstract: A user designates any one of a plurality of types of key ranges via a key range designating switch and designates, for example via a keyboard, a desired key position to be set as a boundary of the designated key range. In response to such user's operations, an actual key range of the designated key range is determined in accordance with the designated boundary key position, and the keyboard is set in a divided usage state, where the keyboard is usable divided in a plurality of key ranges, on the basis of the determined actual key range. For example, once a left (low-pitch-side) key range is designated, the designated boundary key position defines the upper limit of the left key range, while, once a right (high-pitch-side) key range is designated, the designated boundary key position defines the lower limit of the right key range.

Abstract: The protection tube comprises a plurality of threads braided together or interwoven, and is characterised in that at least part of said threads comprises hot melt material. At least part of said threads is impregnated in said hot melt material or is made of hot melt material. It allows the protection tube to be joined, totally or partially, to the element to be protected without requiring the use of any additional element.

Abstract: At least one cam lock and an opposing structure form a compression channel for receiving and engaging a pistol slide. When the pistol is moved in a certain direction through the compression channel, the one or more cam locks and opposing structure engage the pistol's slide and translate some of the forward motion force into a compressive force on the sides of the slide. At a point where the compressive force overcomes the force of the main spring of the pistol, the pistol frame driven by the user moves forward relative to the slide, thereby racking the slide of the pistol.

Abstract: The invention relates to an armor comprising in front to back order at least one rigid first panel comprising inorganic fibers and at least one second panel comprising polymeric fibers, characterized in that the at least one rigid first panel has a flexural strength of at least 300 MPa and the at least one second panel has a flexural strength of at most 250 MPa.

Abstract: An armor assembly for providing resistance to penetration by projectiles includes an impact surface or strike face layer featuring an organic resin composite into which multitudinous ceramic shapes are distributed, a secondary or transition layer to provide mechanical support to the strike face and distribute the imposed load over a wider bearing area, a spacer layer that facilitates reflection of stress waves in the assembly layers between the space and incident projectile, and a back surface that defines the space as well as intercepts any projectile or projectile fragments transiting the space so defined. To this basic assembly can be added components that increase deformation and deflection of incident projectiles, reduce transmitted stresses, or strengthen at least one of the layers.

Abstract: An auto-reset belly for a military vehicle capable of controlled deformation upon receiving a explosive force and automatic reformation upon dissipation of the force is disclosed. The device includes a top panel, first and second side panels, and first and second lower panels, all sequentially connected to form a hexagonal barrier. Along the connected panel edges in some embodiments, the panels are crenellated, interlocking to form hinged joints which are held together by a plurality of hinge rods. The hexagonal configuration has an initial apex and defines an interior volume with a biasing support within the interior volume. In some embodiments, the initial apex is adjustable and the biasing support automatically returns the hexagonal configuration to the initial apex.

Abstract: A turret assembly without deck penetration for minimizing exposure of combatants to enemy forces when accessing above deck equipment comprises a base plate on top of which is mounted at least one finable and remotely operable combatant interfaceable implement, the base plate being rotatable about a substantially vertical axis and supported for rotation by bearing means mounted within a deck of a military facility; a hatch displaceably connected to the base plate, for normally covering a hatchway formed in said base plate and for exposing said hatchway when displaced; and a rotatable disc of a slip ring unit carried by the hatch, by which electricity for operating equipment mounted on top of the deck and for initiating control signals is transmitted to the equipment.

Abstract: A vehicle body inclination angle regulating unit (17) includes a balancing oil cylinder (10). One chamber of the balancing oil cylinder (10) is connected with an oil tank (5) and an oil source for leveling operation via a first one-way damper valve (8) and an electric controlled switch valve (7), and the other chamber of the balancing oil cylinder (10) is connected with a non-rod chamber of a suspension oil cylinder via an electric controlled shutoff valve (14) and a second one-way damper valve (9). In addition, an automatically-leveling hydropneumatic suspension mechanism includes at least two pairs of suspension oil cylinders (12), vehicle body inclination angle regulating units (17), a vehicle body transverse inclination angle sensor (1) and a control unit (3). Each suspension oil cylinder (12) is correspondingly provided with the vehicle body inclination angle regulating unit (17) including the balancing oil cylinder (10).

Abstract: A disclosed cryogenic refrigerator includes a cylinder, a displacer reciprocally moving inside the cylinder, and an elastic unit which is provided in at least one of a pair of end regions respectively including a pair of end portions within a range of a reciprocal motion of the displacer, accumulates an elastic force when the displacer approaches the end portion, and releases the elastic force when the displacer departs from the end portion.

Abstract: A cryogenic refrigerator includes a cylinder; a displacer configured to reciprocate in the cylinder; a driving unit configured to drive a rotational shaft having an axial direction oriented in a direction of reciprocating movement of the displacer; and a movement conversion unit configured to convert rotational movement of the rotational shaft into the reciprocating movement of the displacer. The movement conversion unit is a screw unit including a male thread and a female thread one of which is a part of the displacer.

Abstract: The present disclosure relates to a cylinder having an inner wall formed with fine uneven patterns to improve durability. The fine uneven patterns according to the present disclosure increases oil film pressure between a piston ring and an inner wall of the cylinder, and smoothly supplies engine oil to where the engine oil is insufficient, thereby reducing abrasion between the piston ring and the inner wall of the cylinder.

Abstract: An apparatus and method for coupling a piston to a rod to form a cylinder assembly are provided. The piston has a tapped bore extending therethrough for coupling to a first threaded region of the rod. The rod end extends beyond the piston member and includes a second threaded region for coupling to a tapped bore of a retaining member. The piston member is coupled to the rod member at a low torque, e.g., up to about 1000 Nm. An external thread of each of the threaded segment of the piston bore and the first threaded region of the first portion of the rod member may be formed with a root radius of greater than 0.125 pitch or with MJ class thread. The retaining member may include setscrews offset from one another for frictional engagement with the rod end. The thread pitch between the rod and the piston may be coarser than between the rod and the retaining member.

Abstract: A piston assembly comprises a piston body, a connecting rod, and a wrist pin. The piston body includes a pair of first cross bores presenting a piston sliding surface. The connecting rod includes a second cross bore presenting a rod sliding surface which is axially aligned with the first cross bores of the piston body. A wrist pin is disposed in the aligned cross bores and couples the piston body to the connecting rod. The wrist pin also presents a pin sliding surface facing the rod sliding surface and the piston sliding surfaces. A coating is applied to at least one of the sliding surfaces, such as by dipping, brushing, atomizing, spraying, printing, or screen printing. The coating includes a polymer matrix, such as polyamide imide (PAI), and hard particles, such as Fe2O3, disposed throughout the polymer matrix. The hard particles have a hardness of at least 600 HV/0.5.

Abstract: Various systems and methods are provided for supplying heat to a passenger compartment during a filter regeneration event. In one example, a first phase of a filter regeneration event is initiated for a filter in an internal combustion engine based on one or more parameters, with heat produced by the engine then supplied to a heater core during the first phase, and the first phase extended if heating is requested. The engine may be operated at reduced efficiency during the filter regeneration event, and in some embodiments, the method may further include injecting an additional amount of fuel during a second phase of the filter regeneration event after the first phase ends to cause soot combustion in the filter.

Abstract: A flushable device for capturing gas included within a produced-water stream is described. Gas and water pressure coordination is not required. Controls prevent liquid entry to the gas system and prevent gas entry into the water system. A gas/liquid separator receives an inner vessel lower end. A separator inlet receives a combined fluid stream. A liquid line passes into the inner vessel and down into the separator below the inlet so that liquid separated from the combined stream will flow up the liquid line. The gas line extends from the inner vessel upper end. The gas line conveys gas from the inner vessel upper end to a gas collection system. A top float in the inner vessel activates a gas line motor valve. A bottom float in the inner vessel activates the liquid line motor valve and a second gas vent for rapid expulsion of slugs of gas.

Abstract: A non-cryogenic system for gas separation includes an absorbent system for removing condensable hydrocarbons from a feed gas. The feed gas is then directed into a gas-separation membrane. The absorbent system includes a liquid absorbent having an affinity for hydrocarbons. The liquid absorbent can be, for example, compressor oil or mineral oil. A chiller and a carbon bed may optionally be positioned between the absorbent system and the membrane. The absorbent is periodically regenerated by reducing the pressure or increasing the temperature of the liquid.

Abstract: A composition of and a method of making high performance crosslinked membranes are described. The membranes have a high resistance to plasticization by use of crosslinking. The preferred polymer material for the membrane is a polyimide polymer comprising covalently bonded ester crosslinks. The resultant membrane exhibits a high permeability of CO2 in combination with a high CO2/CH4 selectivity. Another embodiment provides a method of making the membrane from a monesterified polymer followed by final crosslinking after the membrane is formed.

Abstract: This invention provides methods for reducing emissions of mercury from a cement plant comprising at least a kiln (6), a particulate collection device (10), collected particulates, an exhaust gas stream (8b), a heater, and a mercury scrubber, wherein the heater and mercury scrubber are upstream from the kiln. The methods comprise directing the collected particulates through the heater, to form volatilized mercury species from the collected particulates; directing the collected particulates from the heater downstream toward the kiln; and directing the volatilized mercury species to the mercury scrubber. The exhaust gas stream (8c) exits the particulate collection device and is not directed into the heater. Optional steps include injecting a mercury sorbent at one or more points between the kiln and the particulate collection device.

Abstract: The present invention relates to an adsorbent of volatile organic compounds (VOCs) comprising a novel mesoporous polymer, that shows improved adsorption property, and adsorption method of VOCs using thereof. The adsorbent comprises an acrylamide-based polymer.

Abstract: In one embodiment, a carbon dioxide separating and collecting system includes an absorbing tower to cause an absorbing liquid to absorb carbon dioxide, and discharge a rich liquid. The system includes a regenerating tower to cause the absorbing liquid to release the carbon dioxide, and discharge a lean liquid. The system includes a heat exchanger to heat the rich liquid by using the lean liquid. A discharge port of the rich liquid of the exchanger is at a higher position than a supply port of the rich liquid of the regenerating tower so that the rich liquid discharged from the exchanger contains a descending flow by which liquid head pressure loss in a path from the discharge port to the supply port becomes negative, and an absolute value of the liquid head pressure loss becomes larger than an absolute value of flow friction pressure loss in the path.

Abstract: Apparatus and method for removing particles from an air source. The air source is passed through multiple rows (R65) of cyclone separators (65), removing particles from the air to create cleaned air and passing the particles through openings (112) in the separators 65 so that the particles fall to a surface (42) below the openings. The cleaned air is directed into a first chamber region (73) above the cyclone separators (65) and moved along a second chamber region (76) positioned between two of the rows (R65) toward a duct (85) for passage out to a compressor (22).

Abstract: The invention provides a filter for a pipe, the filter comprising an attachment portion for attaching to the pipe, and a filter surface for presentation to and filtering of an oncoming flow of the pipe, wherein the filter surface has at least one pointed apex for protruding into the oncoming flow. The invention also provides a pipe for transporting an oncoming flow, wherein the pipe is provided with a filter surface across the cross-sectional area of the pipe and wherein the filter surface has at least one pointed apex protruding along the longitudinal axis of the pipe. The invention also provides an aircraft with such a filter or pipe and a method of filtering an oncoming flow of a pipe.

Abstract: The present invention relates to a hot gas filtration system and a process for regenerating such a hot gas filtration system, said filtration system comprising a filter vessel, a tubesheet separating the interior of said filter vessel into a raw gas section and a clean gas section, and a plurality of filter elements. Said filter elements, arranged in two or more groups, are connected to the tubesheet with a clean end and extend with a raw gas portion into the raw gas section. Two or more plenum chambers are accommodated in the clean gas section and groupwise accommodate the clean gas ends of the filter elements, each of said plenum chambers comprising a gas exchange opening providing a direct fluid communication with the clean gas section.

Abstract: A plasma spray method for the manufacture of an ion conducting membrane, in particular of a hydrogen ion conducting membrane or of an oxygen ion conducting membrane is suggested. In which method the membrane is deposited as a layer (11) on a substrate (10) in a process chamber, wherein a starting material (P) is sprayed onto a surface of the substrate (10) by means of a process gas (G) in the form of a process beam (2). The starting material is injected into a plasma at a low process pressure which is at most 10000 Pa and is partially or completely melted there. In accordance with the invention the substrate (10) has pores (30) which are connected amongst one another so that the substrate (10) is gas permeable and a portion of an overall pore area of an overall area of the coating surface (31, 131) amounts to at least 30%, in particular to at least 40%.

Abstract: A module and an apparatus incorporating such module utilizing a plurality of tubular membrane elements, each configured to separate oxygen from an oxygen containing feed stream when an electric potential difference is applied to induce oxygen ion transport in an electrolyte thereof. The tubular membrane elements can be arranged in a bundle that is held in place by end insulating members. The insulating members can be positioned within opposed openings of end walls of a heated enclosure and can incorporate bores to allow an oxygen containing feed stream to flow past exposed ends of the tubular membrane elements for cooling the end seals of such elements. Further, first and second manifolds can be provided in a module in accordance with the present invention to collect separated oxygen from two separate portions of the tubular membrane elements.

Abstract: A single-region-board type high temperature electrostatic dust collector comprising anode boards (1), a cathode board (2), emitting electrodes (3) and a high voltage power supply is provided. Two parallel corrosion resistant plates are grounded to form the anode boards (1). One corrosion resistant plate with the same shape and size as the anode boards (1) connects to the cathode of the high voltage power supply, so as to form the cathode board (2), which are suspended between the two anode boards (1) and parallel with the anode boards (1). The disk-shaped emitting electrodes (3) are uniformly embedded at two sides of the cathode board (2).