The invention relates to a dental material which comprises a polymerizable bisphosphonic acid of Formula I: The invention also relates to the use of a polymerizable bisphosphonic acid of Formula I for the preparation of a dental material and in particular for the preparation of an adhesive, cement or composite.

A centrifuge concentrator bowl has feed deposited onto a base of the bowl and includes a plurality of recesses at axially spaced positions along a peripheral wall of the bowl. The peripheral wall is formed of a rigid metal skeleton frame of rings and upstanding support members on which is molded a urethane liner material to form an integral structure with the rings located at ribs between the recesses. A fluidization water injection system includes an outer container on the bowl, which also acts as a clamping assembly and a plurality of liquid entry openings through the peripheral wall at the base of the recesses allowing flexing of the peripheral wall in response to changes in pressure in the fluidizing liquid. The bowl is formed of separate sections defined by a bottom concave base section and the cast skeleton wall all clamped together to allow replacement of the separate parts.

An apparatus for filtering a material from a medium includes a first housing having a wall with a plurality of openings formed therein, a conveyor disposed in the housing for moving the material therealong, and a conduit line communicating with the interior of the housing for supplying the medium to the apparatus. At least one of the first housing and the conveyor rotate relative to a central axis to direct the medium toward the wall so as to separate the material from the medium. A method for filtering a material from a medium includes supplying the medium to a first housing, spinning the medium within the housing, passing the medium through a wall of the housing to separate the material from the medium, moving the material along the housing, introducing a fluid into the material within the housing, and washing the material using the fluid.

A centrifuge includes a vacuum pump machine configured of an auxiliary vacuum pump and an oil diffusion pump for exhausting gas inside a rotary chamber to outside, in which a rotor rotates at high speed. In the centrifuge, a thermistor for detecting a temperature of oil and an oil surface inside a boiler of the oil diffusion pump is provided inside the boiler, and power of a heater is adjusted with the temperature detected by the thermistor, so that a degree of vacuum inside the rotary chamber is stably reduced from atmospheric pressure to a high vacuum state. Besides, when the heater does not heat, a current is carried through the thermistor for self-heating, and it is determined from variation in a resistance value whether the oil exists or not at a position at which the thermistor 8 is placed.

A locking system for axially securing a rotor onto a rotatably mounted shaft. The arrangement includes a plurality of locking levers which are each pivotably mounted about axes extending perpendicularly to the shaft between a locking position and an unlocking position in planes containing the axes. The locking levers can each be automatically transferred between an unlocking position and a locking position depending on rotational speed. The locking levers are mounted on the rotor and an annular groove is provided on the shaft and engages with the locking levers in the locking position, wherein the locking levers are prestressed in the unlocking position. Advantageously, the rotor can be both installed and removed without tools by merely placing the rotor onto or removing the rotor from the shaft, in each case depending on rotational speed.

A gripper unit for handling a vessel for receiving biological material is proposed, inter alia. The vessel has a lid which can assume an open position and a closed position. The gripper unit comprises a gripper for gripping and releasing the vessel, and a lid holder, for holding a lid in a defined position in relation to the vessel. The defined position is an open position of the lid.

Methods and apparatuses for activating colorant in selected regions of an article in which the colorant is incorporated are described. The colorant activation can create various desired visual aspects.

A heat-sensitive recording material includes at least a paper substrate, a heat-sensitive recording layer arranged on the front side of the substrate and which has at least one dye precursor and at least one color acceptor, wherein dye precursor and color acceptor react with one another under the action of heat to form color, and an authenticating security feature. The authenticating security feature is a mark which is applied to the back side of the paper substrate and which is made of a tincture having at least one organic solvent. A barrier coating is arranged between the substrate and heat-sensitive recording layer and is suitable to protect the heat-sensitive recording layer against penetration of the tincture into the heat-sensitive recording layer from the back side.

The present invention provides heat-sensitive coating compositions, which comprise a color developer of formula (1) or mixtures thereof wherein R1 can be hydrogen, C1-20-alkyl, C3-8-cycloalkyl, C2-10-alkenyl, aryl or SO3H, and R2 and R3 can be the same or different and can be hydrogen, halogen, C1-20-alkyl, C3-8-cyclo-alkyl, C2-10-alkenyl, aryl, OR6, NR7R8, SR9, SO3H or COOR10 and R4 and R5 can be the same or different, and can be hydrogen, halogen, C1-20-alkyl, C3-8-cyclo-alkyl, C2-10-alkenyl, aryl, OR6, NR7R8 or SR9, R6, R7, R8, R9 and R10 can be the same or different and can be hydrogen, C1-30-alkyl, C3-8-cycloalkyl, C2-10-alkenyl or aryl, wherein C1-20-alkyl can be unsubstituted or substituted with one or more C3-8-cycloalkyl, C2-10-alkenyl, phenyl, halogen, OR11, NR12R13, SR14, SO3H or COOR15, and aryl can be unsubstituted or substituted with one or more halogen, C1-10-alkyl, halogenated C1-10-alkyl, C3-8-cycloalkyl C2-10-alkenyl, phenyl, OR11, NR12R13, SR14, SO3H or COOR15, wherein R11, R12, R13, R14 and R15 can be the same or different and can be hydrogen, C1-10-alkyl, C3-8-cycloalkyl or C2-10-alkenyl, a process for the preparation of these compositions, a process of coating substrates with these compositions, substrates coated with these compositions, a process for preparing marked substrates using these compositions, marked substrates obtainable by the latter process, and certain color developers.

Provided is a direct thermal media containing a regular repeating pattern of color-forming thermally-imageable stripes printed parallel to the print head element line and a system for using such direct thermal media in color direct thermal printers including an optical registration system optimized for use with this media and an image processing unit that monitors the position of the stripe pattern relative to the print head and synchronizes the start of the printing process. This direct thermal media together with the optical registration system and image processing unit comprise an operative system in that the design of the thermal media, the optical registration system and image processing unit used to control printing are optimized for use with each other. This system may be utilized, for example, in color thermal printers for documents, receipts, tags, tickets or labels.

A heat-sensitive color-developing composition containing a hydroxyquinoline compound having a methyl group and an acid anhydride compound represented by general formula (1): wherein ring A represents a substituted or unsubstituted aromatic hydrocarbon ring, and n represents an integer of 1 to 3, and a heat-sensitive recording material containing the composition in a recording layer.

The invention describes an improved thermally-responsive record material substantially free of aromatic isocyanate yielding an image of high intensity and useful for bar codes. The record material comprises a support having provided thereon a heat-sensitive composition comprising a substantially colorless color former comprising a fluoran; and a developer material selected from the group consisting of 4,4'-diaminodiphenylsulfone and 3,3'-diaminodiphenylsulfone, and an organic acid which upon being heated reacts with said color former to develop color, and including a binder material. Optionally, a modifier compound is included in the heat-sensitive composition. The compound can be selected from the group consisting of a fatty acid amide, such as stearmide. Optionally, magnesium state is included.

The invention describes a thermally-responsive record material substantially free of aromatic isocyanate. The record material comprises a support having provided thereon a heat-sensitive composition comprising a substantially colorless dye precursor comprising a fluoran; and a developer material selected from the group consisting of 4,4'-diaminodiphenylsulfone and 3,3'-diaminodiphenylsulfone in combination with N-[(butylamino)carbonyl]-4-methylbenzene sulfonamide, which upon being heated react with said dye precursor to develop color, and including a binder material.

Disclosed are a polysiloxane-modified polyhydroxy polyurethane resin characterized by being derived from a reaction between a 5-membered cyclic carbonate polysiloxane compound represented by the below-described formula (1) and an amine compound, and its production process; and a resin composition, thermal recording medium, imitation leather, thermoplastic polyolefin resin skin material, weather strip material, and weather strip, all of which make use of the resin. wherein A means

In an intermediate transfer medium, a substrate, protective layers having a layered structure of two or more layers, and a receiving layer are layered in this order. One layer in the protective layers having the layered structure contains, as a main component, one material or a mixture of two or more materials selected from the group consisting of polyesters having a high polymerization degree, a number-average molecular weight (Mn) of not less than 12,000 and a Tg of not less than 60° C., polycarbonates and polyester urethanes. Another layer in the protective layers having the layered structure contains one or more materials selected from the group consisting of polyvinyl alcohols, polyvinyl butyrals, polyvinyl acetals and polyvinyl pyrrolidones or includes a cationic resin, and the receiving layer contains a side chain-type aralkyl-modified silicone in an amount of 0.5-5% by weight on a base of the total weight of the receiving layer.

The invention provides a phenolsulfonic acid aryl ester represented by formula (1) wherein each symbol is as defined in the description. The phenolsulfonic acid aryl ester is useful as a developer to provide a thermal recording material with good color-developing sensitivity, image density when printed at a low application energy (i.e., high start-up sensitivity), and heat and plasticizer resistance. The invention also provides a thermal recording material using the developer.

Provided is a thermal recording material that is excellent in water resistance and prevention of print head wear, less prone to discoloration in the non-printing area, and stably producible. The thermal recording material comprises a protective layer formed by applying a coating liquid for forming the protective layer, the coating liquid being prepared by mixing an acetoacetyl-modified polyvinyl alcohol and calcium glyoxylate particles with a maximum diameter less than 500 μm and an average diameter of 125 μm or less.

To provide a thermosensitive recording material, which contains: a support; a thermosensitive recording layer provided on one surface of the support; and a back layer provided on the other surface of the support, wherein the support has a surface formed of a resin, and wherein the back layer contains a combination of a core-shell acrylic resin and an oxazoline resin, or a reaction product thereof, or both thereof.

The invention describes a thermally-responsive record material substantially free of aromatic isocyanate. The record material comprises a support having provided thereon a heat-sensitive composition comprising a substantially colorless dye precursor comprising a fluoran; and a developer material selected from the group consisting of 4,4'-diaminodiphenylsulfone and 3,3'-diaminodiphenylsulfone, which upon being heated react with said dye precursor to develop color, and including a binder material. Optionally, a modifier compound is included in the heat-sensitive composition. The modifier compound can be selected from the group consisting of a fatty acid amide, preferably a saturated fatty acid amide such as an alkyl amide, a bis methylene alkyl amide, or a bis ethylene alkyl amide, or any of 1,2-diphenoxy ethane, dimethyl diphenoxy ethane, and dimethyl phthalate.

The invention relates to a so-called zero emission ‘AST-CNR/ITM system’ modular plant for removal of pollutants from flue gases produced by industrial processes. The plant comprises prefabricated modular elements with programmed and automatic operation, easy to mount and assemble on site without undergoing expensive plant stoppage. Each module or ‘reaction tower’ comprises a plurality of sections vertically arranged on top of one another, which carry out the following functions: Removal of particulate matter with treatment and removal of chemical pollutants, such as heavy metals, chlorides, fluorides Treatment and removal of SOx Treatment and removal of NOx Capture of CO2 Production of hydrogen Production of methanol. The various sections may be combined according to the requirements of the plant and of the flue gases to be treated.

A method is described for optimizing the operation of a reaction section for the synthesis of hydrocarbons from a feed comprising synthesis gas, operated in the presence of a catalyst comprising cobalt, said method comprising the following steps: a) determining the theoretical partial pressure of CO in the reaction section;b) optionally, adjusting the partial pressure of CO determined in step a) to a value of 4 bar or higher;c) determining a new value for the theoretical partial pressure of CO in the reaction section.

A method for producing synthetic hydrocarbons from at least one carbonaceous material is provided. The method includes evaluating the resources of the carbonaceous material available on a determined territory; determining from the resources a total production capacity of synthetic hydrocarbons; determining from the total production capacity, a number of elementary production units required for obtaining the total production capacity, each elementary production unit having an elementary production capacity between a 100 and a 1,000 barrels a day of synthetic hydrocarbons; building the number of elementary production units on the territory; transporting the carbonaceous material from the territory as far as the elementary production units; producing the synthetic hydrocarbons in the elementary production units from the transported carbonaceous material.

A computer method of material modeling for crash test dummy finite element models includes the steps of making a material card for the material, applying the material card to validate a finite element model of a crash test dummy component, determining whether the finite element model is acceptable, ending the method if the finite element model is acceptable, and adjusting a relative volume (J) range for the material to make the material soft or stiff if the finite element model is not acceptable.

Methods, systems, and computer readable media for simulating realistic movement of user equipment in an LTE network are disclosed. According to one method, a logical topology of a long term evolution (LTE) access network is defined that includes defining connections between one or more eNodeBs (eNBs). A physical topology of the LTE access network is defined that includes defining locations of the eNBs and sectors, where the physical network topology is mapped to the logical network topology. One or more problem areas are defined within the physical network topology, where the one or more problem areas include locations where signal quality is degraded. One or more paths are defined through the physical network topology. A traffic profile for a user equipment (UE) device is defined. A plurality of messages is generated for simulating the movement of a UE device along a path through the physical network topology.

An ink set includes a first ink composition, and a second ink composition, in which the first ink composition contains a first pigment, and an alkyl diol having carbon atoms of 6 or less and a normal boiling point of 240° C. or more, the second ink composition contains a second pigment, and the alkyl diol, in the first ink composition, a content of the first pigment is 2.5% by weight or more, and a content of the alkyl diol is 3% by weight to 15% by weight, in the second ink composition, a content of the second pigment is less than 2.5% by weight, and the content of the alkyl diol is 8% by weight to 30% by weight, and the content of the alkyl diol in the second ink composition is greater than the content of the alkyl diol in the first ink composition.

Systems and methods for controlling the damping of magnetic media for heat assisted magnetic recording are provided. One such system includes a heat sink layer, a growth layer on the heat sink layer, a magnetic recording layer on the growth layer, where the growth layer is configured to facilitate a growth of a preselected crystalline structure of the magnetic recording layer, and a capping magnetic recording layer on the magnetic recording layer, the capping recording layer including a first material configured to increase a damping constant of the capping recording layer to a first preselected level.

Disclosed are polysulfone-based materials that can be used as active and/or passive components in various electronic, optical, and optoelectronic devices, particularly, metal-oxide-semiconductor field-effect transistors. For example, various metal-oxide-semiconductor field-effect transistors can include a dielectric layer and/or a passivation layer prepared from such polysulfone-based materials and exhibit good device performance.

A method for perfusing a biocompatible material graft with a perfusion liquid includes the steps of: introducing the graft (100) in a perfusion chamber (2), arranging a transfer chamber (3) partly filled with the perfusion liquid (101), coupling in a tight manner the perfusion chamber (2) and the transfer chamber (3) for establishing a fluid communication between them, lowering the pressure in the transfer chamber (3) for transferring therein part of the air existing in the perfusion chamber (2), increasing the pressure within the transfer chamber (3) for injecting in the perfusion chamber (2) the perfusion liquid (101) existing in the transfer chamber (3). A perfusion kit includes a perfusion chamber (2) apt to contain a graft (100) to be perfused with a liquid (101) and a transfer chamber (3) apt to contain a liquid (101) to be perfused, the perfusion chamber (2) being connectable in a tight manner with the transfer chamber (3) for allowing a fluid exchange between the two chambers (2, 3) and inhibiting a fluid exchange between the two chambers (2, 3) and the external environment.

An intracorporeal autonomous active medical device having a capsule body and a base. The capsule body includes a body portion and a lid portion, and the capsule body contains therein electronic circuitry containing the active elements of the autonomous medical device, and a power supply. The capsule body also includes a fastening system on an exterior surface of the capsule body that is configured to correspond with a fastening mechanism on the base configured to be anchored to a tissue wall. The fastening mechanism provides selective engagement between the capsule body and the base.

A retractable screw-type stimulation or defibrillation intracardiac lead is disclosed. According to one embodiment, the lead comprises a flexible hollow sheath (12) having at its distal end a lead head (10) and a connector (66) at its proximal end. The connector comprises a pin (62) connected to a lead head electrode (18). The lead head comprises a tubular body (28), at least one electrode (18, 20) for stimulation or defibrillation, a moving element translationally and rotationally moving within the tubular body in a helical motion, an anchoring screw (24) axially moving with respect to the tubular body, and a deployment mechanism (22) to deploy the anchoring screw out of the tubular body (28). The lead is a co-radial type, and the moving element (26) secured to the anchoring screw is connected to the tubular body (28) by a helical guide (46) and a coupling finger (56) protruding between two successive turns of the helical guide (46) for transforming a rotary movement imparted to the lead body in a deployment or retraction movement of the moving element (26). The helical guide (46) is resiliently compressible, with a free end (52) with a flat area (54) facing a flange (38) in vis-à-vis, so as to pinch the coupling finger (56) and to perform the function of a clutch limiting the torque transmitted to the anchoring screw by the rotation of the lead body, even in case of continuation of this rotation.

The portable, wearable, proximal Alzheimer's disease treatment invention is based upon creating an RF field of particular frequencies and intensities that are applied to the patient's head. To accomplish the aforementioned disease treatment functionality, a system was invented comprising a network of antennas connected to an RF generator via a feedline connector. The invention also provides methods for using measurements to monitor and manage the effectiveness of an ongoing disease treatment regimen, and databases which contain information about measurements, variables, and their relationships to clinical outcome.

Cells that are in the process division are vulnerable to damage by AC electric fields that have specific frequency and field strength characteristics. The selective destruction of rapidly dividing cells can therefore be accomplished by imposing an AC electric field in a target region for extended periods of time at particular frequencies with particular filed strengths. Some of the cells that divide while the field is applied will be damaged, but the cells that do not divide will not be harmed. This selectively damages rapidly dividing cells like bacteria, but does not harm normal cells that are not dividing. Since the vulnerability of the dividing cells is strongly related to the alignment between the long axis of the dividing cells and the lines of force of the electric field, improved results can be obtained when the field is sequentially imposed in different directions.

A component for a laser tool, the component comprising: a tubular body defining an internal channel and an aperture; and a window disposed across the aperture and bonded to the tubular body around the aperture, wherein the window is diamond, and wherein the tubular body comprises a material having a coefficient of linear thermal expansion α of 14×10−6 K−1 or less at 20° C. and a thermal conductivity of 60 Wm−1K−1 or more at 20° C.

Methods and devices for cardiac signal analysis in implantable cardiac therapy systems. Several signal processing and/or conditioning methods are shown including R-wave detection embodiments including the use of thresholds related to previous peak amplitudes. Also, some embodiments include sample thresholding to remove extraneous data from sampled signals. Some embodiments include weighting certain samples more heavily than other samples within a sampled cardiac signal for analysis.

Cardiac pacing methods for an implantable single chamber pacing system, establish an offset rate for pacing at a predetermined decrement from either a baseline rate (i.e. dictated by a rate response sensor), or an intrinsic rate. Pacing maintains the offset rate until x of y successive events are paced events, at which time the offset rate is switched to the baseline rate for pacing over a predetermined period of time. Following the period, if an intrinsic event is not immediately detected, within the interval of the offset rate, the rate is switched back to baseline for pacing over an increased period of time. Some methods establish a preference rate, between the offset and baseline rates, wherein an additional criterion, for switching from the offset rate to the baseline rate, is established with respect to the preference rate.

A leadless pacemaker for pacing a heart of a human includes a hermetic housing and at least two electrodes on or near the hermetic housing. The at least two electrodes are configured to deliver energy to stimulate the heart and to transfer information to or from at least one external device.

Embodiments of the present concept are directed to medical devices having features that prevent contaminants from infiltrating the housing of the device while providing a mechanism to provide clear auditory sounds to aid a rescuer in providing care to a patient. In one example, a medical device includes a housing having a transmission area associated with an enclosed voice coil. An exterior diaphragm formed integrally with the housing surrounds the transmission area and provides a watertight seal of the transmission area. In addition, the diaphragm is structured to generate a sound that can be heard by the rescuer from the voice coil.

An apparatus for forming pressed food products can utilize up to 98% chicken breast meat in high profit margin products. Breast meat is marinated and then extruded into a slab which is then frozen and shaped into a plank. The plank is sliced into unit portions which are then pressed into shaped portions with a preferred, or other, press. One preferred press linearly reciprocates unit portions into the press. This or another preferred press imparts three dimension exterior shape to the pressed food products.

An apparatus and method for the shaping of plastics material pre-forms into plastics material containers with at least one blow moulding station which is arranged on a conveying device rotatable about a pre-set axis of rotation (D). The blow moulding station has a blow mould and this blow mould forms a cavity in the interior of which the plastics material pre-forms are capable of being expanded by being acted upon with a gaseous medium to form the plastics material containers, with a stressing device, which acts upon the plastics material pre-forms with the gaseous medium in order to expand them, and with a clean room, which surrounds the blow moulding station at least in part. The clean room is bounded off from an environment by at least two walls which are movable relative to one another.

An apparatus for extruding a polymeric material, having an extrusion head which includes a male die, a female die coaxially arranged with respect to the male die, a conveying channel, and at least one portion of which is defined between the male die and the female die. The apparatus further includes a device for adjusting a cross-sectional area of the at least one portion of the conveying channel by reciprocally displacing the female die with respect to the male die in response to an extrusion speed variation of the polymeric material.

A combustor apparatus is provided, comprising a mixing arrangement for mixing a carbonaceous fuel with enriched oxygen and a working fluid to form a fuel mixture. A combustion chamber is at least partially defined by a porous perimetric transpiration member, at least partially surrounded by a pressure containment member. The combustion chamber has longitudinally spaced apart inlet and outlet portions. The fuel mixture is received by the inlet portion for combustion within the combustion chamber at a combustion temperature to form a combustion product. The combustion chamber directs the combustion product longitudinally toward the outlet portion. The transpiration member is configured to substantially uniformly direct a transpiration substance therethrough toward the combustion chamber, such that the transpiration substance is directed to flow helically about the perimeter and longitudinally between the inlet and outlet portions, for buffering interaction between the combustion product and the transpiration member. Associated systems are also provided.

The invention relates to a gas burner for a gas cooking appliance with at least one gas hob and/or one gas oven, wherein the gas burner (10) comprises a heat source (18) and an electric ignition system (24), and wherein an electric or electronic control circuit (38) is provided for controlling the electric ignition system (24). According to the invention the gas burner (10) includes a photovoltaic generator (20) for generating the electric power for the electric ignition system (24).

A service method of gas appliances includes: Detecting the gas appliances at the client ends to generate detecting signals. Transmitting the detecting signals to a service end. Identifying which client end the detecting signals come from. Examining the detecting signals to find whether the gas appliance has an abnormal condition; and informing the client end when the abnormal condition is found. After all, the service end may monitor the gas appliances at the client end, and inform the client for repair when the gas appliance has detected an abnormal signal or has damaged parts.

Provided is an actinic-ray- or radiation-sensitive resin composition including (A) a compound that when exposed to actinic rays or radiation, generates an acid, (B) a resin that when acted on by an acid, increases its rate of dissolution in an alkali developer, and (C) a hydrophobic resin, wherein the hydrophobic resin (C) contains a repeating unit derived from any of monomers of general formula (1) below.

A radiation-sensitive resin composition that provides a resist coating film in a liquid immersion lithography process is provided, the radiation-sensitive resin composition being capable of exhibiting a great dynamic contact angle during exposure, whereby the surface of the resist coating film can exhibit a superior water draining property, and the radiation-sensitive resin composition being capable of leading to a significant decrease in the dynamic contact angle during development, whereby generation of development defects can be inhibited, and further shortening of a time period required for change in a dynamic contact angle is enabled. A radiation-sensitive resin composition including (A) a fluorine-containing polymer having a structural unit (I) that includes a group represented by the following formula (1), and (B) a radiation-sensitive acid generator.

The present invention provides a polymerizable tertiary ester compound represented by the following general formula (1a) or (1b). There is provided a polymerizable ester compound useful as a monomer for a base resin of a resist composition having a high resolution and a reduced pattern edge roughness in photolithography using a high-energy beam such as an ArF excimer laser light as a light source, especially in immersion lithography, a polymer containing a polymer of the ester compound, a resist composition containing the polymer as a base resin, and a patterning process using the resist composition.

In production of a casein-type artificial key material for keyboard musical instruments, fine grains of an elastomer such as polyurethane elastomer are added to a mixture to be kneaded together so that, in the structure of the product, islanded elastomer is uniformly dispersed in the matrix of casein. Inbred brittleness of casein is much improved by inclusion of the elastomer and strong bond between casein and the elastomer well removes the danger of interface separation.

The present invention discloses a method for displaying individually on a plurality of keys of a keyboard or keypad two or more indicia representing two or more functions performed by each key. The keys are characterized in that each of the two or more indicia is provided on the key in a plurality of separated portions. The portions being positioned in a spaced positioned relationship with one another, so as not to be physically closely juxtaposed. When viewed at a predetermined angle all parts of the indicia are optically juxtaposed to create the entire indicia.

Described is a bass drum foot pedal having a variable drive lever linkage with variable arc ratios connecting the foot pedal to a beater bracket. The beater bracket is formed with a mounting surface that tips a beater shaft forward to create a forward beater angle that maximizes the beater impact against a bass drum.

A dual rotor axial-flow rotor valve structure includes a rotor valve seat for rotatably receiving rotatable first and second rotor valves. The rotor valve seat has a first and a second extension sections connected to end sections of a second and a first tuning slide assembly s. The first rotor valve communicates with end sections of first and second flow passages with a mouthpiece and the other end of the second tuning slide assembly and communicate the other end of the second flow passage with the first or second extension section. The second rotor valve communicates ends of the first and second flow passages with the other end of the first tuning slide assembly and a main tuning slide assembly and communicate the other end of the second flow passage with the first or second extension section.