A floor washing mop has a rigid base carrying fixed scrubbing members on the bottom surface. The scrubbing members may be stiff flexible bristles or rigid elastomeric rails. A rabbet is formed at each side of the base stepped down from the upper surface of the base and a groove is stepped down from the upper surface and extends between the rabbets adjacent the front of the base. A U-shape clamp is pivoted to the base and receivable within the rabbets and the groove. A fabric covering is positionable about the entire base including the scrubbing members and foldable so as to rest on the top of the base and is held securely in position by the clamp. A locking member mounted on the upper surface of the base locks the clamp on the covering.

This invention relates to cleaning implements and more particularly to a mop having scrubbing elements over which a replaceable web of covering material is folded and clamped, the covering receiving the dirt and grime as the mop is used to wash and scrub a floor.
Mops of various designs have been developed over the years for washing floors. For example, the conventional string or rope type mops absorb a substantial amount of water or a cleaning solution and are useful when a floor surface is to be washed, but they are inefficient when a scrubbing action is required. Additionally, after a number of uses the string or rope elements become excessively soiled and worn and require replacement. These elements are generally affixed to a base which must also be replaced as a unit. The same deficiencies are presented by mops of this design wherein fabric or other material comprise string-like elements. The development of sponge or artificial sponge mops, that is, mops having a sponge or artificial sponge as the cleaning solution absorption element, provide a more efficient scrubbing action than the string type mops, but the useful life of the sponge portion of such mops is very limited, not only because the sponge wears rapidly, but because it quickly takes on a sour smelling odor. Such mops cannot be washed in a washing machine or the like. Moreover, even though the scrubbing ability of the sponge or artificial sponge is substantially greater than that of the string or rope mops, many people when washing a floor prefer to use a hand-held hard bristle brush because of the greater scrubbing or scouring abilities it provides to the floor surface.


A method of securing a holster to the shoulder of a person wearing a neck encircling garment, such as a tie, by encircling the shoulder of the person with a loop and connecting this loop to the neck encircling garment. The loop can be connected to the neck encircling garment with a second smaller loop which engages around the neck encircling garment and which engages in slots formed in the first loop.

Shoulder holsters are known which are provided with loops or straps which are connected thereto by means of rings or like mechanisms. These loops are generally so positioned as to encircle the shoulder portion of a wearer. Usually, these loops are not adequate to hold the holster in position so that a supplemental structure has to be provided to hold the loop and thereby the holster on the shoulder of the wearer. Such supplemental structures usually are provided in the form of elastic straps or the like which extend across the back of the wearer and are looped around the opposite shoulder of the same.
Structures of the above-indicated type are frequently deemed uncomfortable and function to constrict the movement of the wearer. In fact, the elastic bands which extend across the back of the wearer are capable of impairing circulation and causing various types of discomforture as well as adding to an unsightly appearance by being visible through the outer garments of the wearer.
In researching the prior art to determine whether my invention is new, I have not actually found any prior art which might be considered anticipatory. However, for the sake of making complete disclosure, I note the existence of U.S. Pat. No. 723,545 which issued to R. Phillips on Mar. 24, 1903. This patent proposes means whereby a firearm at the convenience of a wearer is held at the belt and when desired can be instantly adjusted to hand immediately under the armpit so that when the user desires to discharge the firearm from the shoulder he can bring it into proper position at the shoulder. A shoulder strap serves as a guide and adjusting device to bring the shoulder piece or stock of the firearm into position in front of the shoulder for aiming and firing. In one embodiment thereof a loop connected to the firearm passes through a loop arranged on the shoulder of the wearer. This second loop while bearing some minimal structural resemblance to the preferred embodiment of my invention is nevertheless remote therefrom as will be seen in the description which follows hereinafter.

Shoulder holster with means to secure the same to wearer's garment


An apparatus and method for displaying a portion of plurality of background applications are provided, wherein an open application is in the foreground and one or more other open applications are in the background. The method includes receiving a user input to display an application currently in the background, in response to the user input, removing a portion of the application in the foreground, at a location on the display screen where the portion of the foreground application is removed, displaying at least a portion of an application currently in the background, and maintaining, at remaining locations, display of the application in the foreground.

Mobile terminals are developed to provide wireless communication between users. As technology has advanced, mobile terminals now provide many additional features beyond simple telephone conversation. For example, mobile terminals are now able to provide additional functions such as an alarm, a Short Messaging Service (SMS), a Multimedia Message Service (MMS), E-mail, games, remote control of short range communication, an image capturing function using a mounted digital camera, a multimedia function for providing audio and video content, a scheduling function, and many more. With the plurality of features now provided, a mobile terminal has effectively become a necessity of daily life.
On a desktop/laptop or comparable computer that offers a larger screen than a mobile device, switching between applications or displaying multiple windows is not difficult. However, on a small screen device such as a mobile terminal, displayed information is generally limited to only a single application at a time. When a user needs to refer to a different application, the user much change applications. Another solution is "Multi Window" but this is limited to particular apps; further, Multi Window in a mobile terminal occupies at least third of an entire screen, even if the user would see only a small portion of another page.
Rytivaara (US Pat. App. Pub. 2008/0163082, "Transparent layer application") describes displaying two applications simultaneously, where the second application is transparently presented over the first application. Also, the first application is operated through a keypad and the second application is operated through touch screen.
Some distinctions from Rytivaara's invention are that the present disclosure provides capabilities that a user can see a background application through the foreground application, the portion of view can be moved around, and the user can choose at which level of background an application will be displayed so that the portion of view is not interfering with the user seeing a foreground application. The main disadvantage of Rytivaara's invention is that different input operations will tend to make the user confused, and the view of the top application will interfere with the user seeing a second application.
Diefendorff (U.S. Pat. No. 4,868,765, "Porthole window system for computer displays") describes that a porthole window system for computer displays allows a user to look at a portion of a window which could otherwise not be seen. A porthole window acts as an opening in a window of the usual type through which underlying windows may be seen. A porthole window can have different features as desired, including links to selected source and target windows, real time movement on the display screen, and the ability to be updated when a target window is updated. The porthole system runs concurrently with the normal window handling system of the computer. The porthole system is related art in terms of seeing an underneath application through a porthole on top of the foreground application. However, the porthole system does not include a control to change the level of the underneath application that will be seen through porthole. Further, the view size is fixed, and cannot swap the view level by selecting a currently visible underneath application.
Gedye (U.S. Pat. No. 5,425,141, "Managing display windows of inter-related applications using hollowed windows") describes that at least one background display window is generated and displayed behind a hollowable portion of the foreground display window, rendering the visibility and accessibility of the at least one background display window to be dependent on the foreground display window. Gedye's invention is similar to a pop-up window related to the foreground application. Gedye's invention has the ability to show only inter-related applications, such as right click on a mouse or menu pop-up.
Weber, et al. (US Pat. App. Pub. 2013/0152010, "Multiple tab stack user interface") describes displaying multiple web pages in a stack like tab Graphical User Interface (GUI) to switch tab in Chrome. Weber's invention is related in that that multiple tabs are stacked, but does not feature switching tabs and manipulating the level of the tabs.
Clausen, et al. (US Pat App. Pub. 2014/0201660, "Apparatus and method for application peel") describes peeling an application view to manage a plurality of applications concurrently running. Only a predefined portion of a foreground application can be peeled, and only a predefined area of a background application can be present.
Accordingly, there is a need for an apparatus and method for providing an improved user interface displaying a plurality of background applications in a mobile terminal.

Apparatus and method for displaying a portion of a plurality of background applications


The invention provides compositions comprising BCB-functionalized materials for use in OLEDs applications. The inventive compositions can be used to form hole-transporting materials for use in electroluminescent devices. In particular, the invention provides for compositions, charge transport film layers, and light emitting devices, comprising, or formed from, a polymer, which comprises one or more polymerized units derived from Structure (A).

Organic light emitting diodes (OLEDs) are display devices that employ stacks of films containing organic aromatic compounds as electron transport layers (ETLs) and hole transport layers (HTLs). New material discovery for electron transport layer (ETL) and hole transport layers (HTL) in organic light emitting diodes (OLEDs) have been targeted to improve device performance and lifetimes. In the case of the HTL layer, the process, by which the layer is deposited, is critical for its end-use application. Methods for depositing the HTL layer, in small display applications, involve evaporation of a small organic compound, with a fine metal mask, to direct the deposition. In the case of large displays, this approach is not practical from a material usage and high throughput perspective. With these findings in mind, new processes are needed to deposit HTLs that satisfy these challenges, and which can be directly applied to large display applications.
One approach that appears promising is a solution process which involves the deposition of a small molecule, followed by crosslinking or polymerization chemistry. There have been extensive efforts in this area, along these lines; however these approaches have their own shortcomings. In particular, the mobility of the charges in the HTL layer becomes reduced, as a result of crosslinking or polymerization chemistry. This reduced hole mobility leads to poor device lifetime and difficulty in maintaining a charge balanced device. This imbalance can also lead to device efficiency issues. Also, the current technology can hardly produce an insoluble HTL film, with few to no reactive end groups, at desirable process conditions.
Benzocyclobutene (BCB) chemistries and their use in OLEDs are described in the following: US20040004433, US20080315757, US20080309229, US20100133566, US20110095278, US20110065222, US20110198573, US20110042661, JP2010062120, U.S. Pat. No. 7,893,160, US20110089411, US20070181874, US20070096082, CN102329411, US20120003790, WO2012052704, WO2012175975, WO2013007966, International Application No. PCT/CN14/084915 (filed Aug. 21, 2014) and International Application No. PCT/CN14/084918 (filed Aug. 21, 2014).
However, there remains a need for new compositions for improved hole-transporting materials, and for improved processing of the same. These needs have been met by the following invention.

Oxygen substituted benzoclobutenes derived compositions for electronic devices


A device and process for mass transfer between liquid and gaseous media. Obstacles in the form of orifice plates or discs are installed in a flow channel bearing a gaseous medium, of the device. The obstacles define between them cavities which act as resonance cavities which result in flow forms and pulsations which lead to improved mass transfer with the liquid medium sprayed in through a high-pressure nozzle.

1. Field of the Invention
The present invention relates to a process for mass transfer between liquid and gaseous media by spraying the liquid medium into a flow of the gaseous medium generated by forced delivery, and to a device for carrying out the process.
2. Description of the Related Art
For air humidification or flue gas purification, for example, it is known to spray a liquid through spray nozzles into a flow channel of relatively large cross-section, in order to achieve vaporization of the greatest possible proportion of the liquid into the gas stream. At the end of the flow channel, impingement plates are provided for precipitating unvaporized liquid droplets and to return them to a collecting tank.
GB-A 364,239 discloses a gas-washing device which at the same time can be used for humidifying or dehumidifying gases. The device has a spray chamber in which the liquid to be washed is sprayed into a gas flow. Downstream of the spray chamber, a scrubber is provided in which a multiplicity of plates provided with small holes are located. Forcing of the gas through the perforations effects strong turbulence and more complete washing of the gas.
EP-A2 0,352,902 describes a device for mass transfer and heat exchange between a fluid stream and a boundary layer, for example on a membrane. The device has a flow channel for the fluid and a pump for pulsed feeding of the fluid. To obtain improved exchange, obstacles for creating turbulence of the fluid are provided in the flow channel.

Process and apparatus for mass transfer between liquid and gaseous media


Method and apparatus for the thermal treatment of pulverulent material in which the material is preheated and finely calcined in a calcination zone, the improvement involving pre-calcining the pulverulent material in a highly turbulent gaseous stream containing combustible fuel in a pre-calcination zone prior to final calcination.

1. Field of the Invention
This invention is in the field of thermal treatment of pulverulent material involving both a pre-calcining and a calcining zone, the pre-calcining being carried out in a highly turbulent gaseous atmosphere derived from the calcining zone, and including combustible fuel and preferably added oxygen containing gas, the gaseous atmosphere thus created passing through the pre-calcining zone at a very substantial linear velocity.
2. Description of the Prior Art
In the production of cement, argillaceous earth, lime, dolomite or the like, the heat treatment of the finely granular pulverized raw material is required. Typically, the prepared pulverized material is first delivered to a preheater section where it is suspended in a heat exchanger consisting of several cyclone separators connected in series and superimposed. Particles of the raw material are thereby preheated by the hot exhaust gases of a rotary kiln, the gases acting in countercurrent relationship to the pulverized material in the cyclone separators. Such thermal treatment provides deacidification of the pulverized material to a predetermined degree, before the particles are charged into the rotary kiln where they are calcined to completion. In this conventional method, almost the entire thermal energy is supplied to the rotary kiln, and a non-uniform distribution of heat occurs in the rotary kiln. The thermal degree of effectiveness and the output capacity of the furnace are limited and the life of the refractory bricks in the combustion zone is substantially reduced. In order to provide rotary kilns with a smaller cross-section and/or a furnace length, it has been attempted to undertake a low temperature calcination process of the pulverized raw material in a pre-combustion zone between the preheater and the furnace. For such a system to be effective, there must be an intimate mixture of fuel and raw material in the pre-combustion zone so that for the calcination of the pulverized raw material, the heat of the fuel may be imparted to the individual particles of the pulverized raw material.
In German Laid Open Specification No. 2,361,427 there is described a pre-combustion zone which is constructed in the nature of a shaft and contains a mixing zone laterally on the shaft for the separate feed of fuel and pulverized raw material used in the manufacture of cement. This mixture of fuel and raw material is then brought into contact with an upwardly directed stream of oxygen-containing gas received from a rotary kiln. In this type of arrangement, it is difficult to achieve a uniform mixture in the feed pipe and such a mixture can only take place with the aid of mechanical mixers. A further disadvantage of the mixing of fuel and pulverized raw material before they are directed into the stream of gas is that undesirable chemical reactions result between the fuel and the alkali-containing or sulfer-containing raw material which are detrimental to the entire calcining process.
In German Laid Open Specification No. 2,324,519 there is described another type of preheating arrangment utilizing a combustion zone between the preheater and the rotary kiln together with a fuel feed conduit in such a way that the fuel feed conduit is covered by the stream of material being introduced. In this arrangement, it is not possible to adjust the distribution of the quantities of material being introduced so that at predetermined points in the combustion zone, the concentration of raw material is so great that poor combustion or calcining conditions prevail. At other points, the concentration of raw material is relatively low so that at these points the particles reach especially high temperature peaks, with the consequence of over-calcination of the particles of material. The resulting coarsening of the grain and incipient melting appreciably impairs the flow capacity of the raw material and leads to disturbances in the entire installation.
German Laid Open Specification No. 2,365,653 describes an apparatus for the heat treatment of finely grained material with a preheating shaft in which exhaust gases from a rotary kiln flow. An additional combustion zone is provided through which the material is passed twice, once in a downward direction and upwards in the other. In order to achieve this result, the gas velocity must not be too great. Normally, the velocity of the combustion zone is not in excess of about 7 meters per second. This is typical for hot gas velocities currently used, in which the velocity is on the order of 7 to 20 meters per second. A uniform mixture of fuel and material in the preheating shaft and, therefore, a uniform heat treatment of the material is, however, not achieved as in the combustion zone the gases rising up cannot break up the clusters of material and the fuel gives off heat to the outer particles of the materials in the clusters, so that individual particles may be heated too high and others may be heated too little. In addition, such an installation provides undesirably high exhaust gas temperatures as the quantity of fuel theoretically adjusted to the quantity of the raw material cannot give off heat efficiently to the particles of pulverized raw material and the stream of hot gas is heated undesirably high.

Method and apparatus for the thermal treatment of pulverulent material particularly for the calcining of cement


An apparatus including a complimentary metal oxide semiconductor (CMOS) inverter including an n-channel metal oxide semiconductor field effect transistor (MOSFET); and a p-channel MOSFET, wherein a material of a channel in the n-channel MOSFET and a material of a channel in the p-channel MOSFET is subject to a bi-axial tensile strain. A method including forming an n-channel metal oxide semiconductor field effect transistor (MOSFET); forming a p-channel MOSFET; and connecting the gate electrodes and the drain regions of the n-channel MOSFET and the p-channel MOSFET, wherein a material of the channel in the n-channel MOSFET and a material of the channel in the p-channel MOSFET is subject to a bi-axial tensile strain.

For the past several decades, the scaling of features in integrated circuits has been a driving force behind an ever-growing semiconductor industry. Scaling to smaller and smaller features enables increased densities of functional units on the limited real estate of semiconductor chips. For example, shrinking transistor size allows for the incorporation of an increased number of memory devices on a chip, lending to the fabrication of products with increased capacity. The drive for ever-more capacity, however, is not without issue. The necessity to optimize the performance of each device becomes increasingly significant.
Increase carrier mobility (beyond a carrier mobility of silicon) is desired to continue scaling transistor devices, including complementary metal oxide semiconductor (CMOS) inverters and to deliver increased performance and lower power. Promising materials such as group III-V compound semiconductor materials offer high electron mobility for n-channel metal oxide semiconductor field effect transistors (MOSFETs) and germanium based materials offer high hole mobility for p-channel MOSFETs. Because of differences between group III-V compound semiconductor materials and germanium materials, there are significant challenges integrating the two separate systems on silicon in a highly scaled CMOS inverters for sub-10 nanometers (nm) node geometries. Additionally, thin film stacks including buffer layers, gate stacks, contacts, etc. are expected to be different for group III-V compound semiconductors and germanium which further increases a complexity of integrating these different channel materials for scaled CMOS.

Bi-axial tensile strained GE channel for CMOS


A method for determining the nucleotide sequence of a chromosome. The chromosome is hydrolyzed to form a mixture of oligonucleotides having unknown nucleotide sequences. The mixture is exposed to a library of oligonucleotide probe pairs having known sequences. The probe pairs are located so that they hybridize to outer opposed sections of the chromosomal oligonucleotides. The use of oligonucleotide probe pairs provides for sequencing of relatively long unknown DNA sequences using relatively short oligonucleotide probes.

This invention relates generally to the field of gene sequencing. More particularly, this invention relates to a gene sequencer, a high density bio-compact disk useful therewith and a method of sample preparation therefor. The high-density bio-compact disk and the sample preparation methodology find application in the field of oligonucleotide sequencing and DNA sequencing and detection generally.
In one aspect, the present invention features a sample preparation method for obtaining n-mer oligonucleotides from a sample containing oligonucleotide fragments comprising: (a) forming a solid support having all possible n-mer oligonucleotides attached to the surface of the support; (b) contacting the solid support resulting from step (a) with the sample under conditions causing the sample oligonucleotides to hybridize with the complementary n-mer oligonucleotides on the solid support; (c) contacting the solid support resulting from step (b) with a hydrolyzing agent; (d) separating the unbound oligonucleotides from the hybridized oligonucleotides; and (e) denaturing the hybridized n-mer oligonucleotides to obtain the n-mer oligonucleotides of the sample; wherein n is an integer selected from the integers 4-10,000, most advantageously 6-28.
In another aspect, the invention features a method of obtaining n-mer oligonucleotides from a sample containing oligonucleotide fragments comprising: (a) contacting a solid support adapted to couple with oligonucleotides in the sample with at least a portion of the sample; (b) contacting the solid support resulting from step (a) with a mixture of n-mer oligonucleotides for a time sufficient for the n-mer oligonucleotides to hybridize with the complementary n-mer oligonucleotides on the solid support; (c) separating the hybridized n-mer oligonucleotides from the unhybridized oligonucleotides; (d) denaturing the hybridized n-mer oligonucleotides to obtain the n-mer oligonucleotides complementary to those present in the sample; wherein n is an integer selected from the integers 4-10,000, most advantageously 6-28.
In still another aspect, the sample preparation method includes a method of obtaining n-mer oligonucleotides from a sample containing oligonucleotide fragments comprising: (a) contacting a solid support having bound thereon oligonucleotides from a sample with a mixture of a plurality of oligonucleotides having (k+m)-mers, wherein k+m=n, with a mixture of a plurality of first oligonucleotides, each being a k-mer and being without a free hydroxyl group at the 3xe2x80x2-end thereof, and a plurality of second oligonucleotides, each being a m-mer and being without a free phosphate group at the 5xe2x80x2-end thereof; (b) ligating the oligonucleotides on the solid support resulting from step (a); (c) removing the unligated oligonucleotides from the solid support; and (d) denaturing the hybridized n-mer oligonucleotides remaining on the solid support to obtain the n-mer oligonucleotides complementary with those present in the sample; wherein m, k and n are each an integer selected from the integers from 6-10,000, most advantageously 12-40, with the proviso that k+m=n.
In yet another aspect, the sample preparation method includes a method of obtaining n-mer oligonucleotides from a sample containing oligonucleotide fragments comprising: (a) contacting a solid support having bound thereon a plurality of oligonucleotides from a sample with a mixture of a plurality of h-mer oligonucleotides each having a phosphate group at both the 3xe2x80x2- and 5xe2x80x2-end, a plurality of i-mer oligonucleotides each having a hydroxyl, amino or thiol group at the 3xe2x80x2-end and no terminal phosphate group, and a plurality of j-mer oligonucleotides having a hydroxyl, amino or thiol group at the 5xe2x80x2-end and no terminal phosphate group; (b) chemically or enzymatically ligating the oligonucleotides on the solid support resulting from step (a); (c) removing the unligated oligonucleotides from the solid support resulting from step (b); and (d) denaturing the hybridized n-mer oligonucleotides remaining on the solid support to obtain the n-mer nucleotides complementary with those present in the sample; wherein h, i and j are each an integer selected from the integers from 6-10,000, most advantageously 18-60, with the proviso that h+i+j=n.
In yet another aspect of this invention, an assay element is described comprising a substrate having a surface including a plurality of discrete areas on the surface adapted to attach to a spacer molecule; a plurality of spacer molecules attached at a first end to said surface in each of the discrete areas, each of said spacer molecules adapted to being attached at its second end to a metallic surface or a label, each of said spacer molecules having a site between its first end and its second end capable of being cleaved; a first n-mer oligonucleotide having a first sequence attached to substantially all of the spacer molecules between the cleavage site and the first end of the spacer molecule, and a second n-mer oligonucleotide having a second sequence attached to substantially all of the spacer molecules; wherein substantially no other discrete areas on the surface of the substrate contain spacer molecules having n-mer oligonucleotides having the first sequence attached thereto and n is an integer selected from the integers 4-10,000, most advantageously 6-28.
The present invention also encompasses a method for determining the sequence of a (p+q+r)-mer segment of a gene suspected of being present in a sample comprising: (a) forming a solution of the sample and a mixture of q-mer oligonucleotides having all possible sequences of a q-mer oligonucleotide, or, optionally, a subset of all such possible sequences; (b) contacting an assay element with at least a portion of the solution of step (a), the assay element having a surface and plurality of spacer molecules bound to the surface, the spacer molecules having a first end bound to the surface and a second end bound to a metallic surface or a label and a cleavage site intermediate between the first and second ends, the spacer molecules further having a first p-mer oligonucleotide attached thereto between the cleavage site and the first end and a second r-mer oligonucleotide attached thereto between the cleavage site and the second end, the combination of p-mers and r-mers including all combinations of oligonucleotide sequences of p-mer and r-mer oligonucleotides, or, optionally, a subset of all such combinations, each particular combination of sequences of the p-mer and r-mer oligonucleotides being at a predetermined location on the surface; (c) ligating the resultant hybridized oligonucleotides attached to the spacer molecules resulting from step (b) above; (d) detecting the presence or absence of a particular sequence combination of the hybridized oligonucleotides at each predetermined location on the surface; and (e) processing the sequence information obtained from step (d) to deduce the sequence of the (p+q+r)-mer oligonucleotide present in the sample, wherein p, q and r are integers selected from the integers 4-10,000, most advantageously 6-26, and (p+q+r) does not exceed 30,000, and most advantageously 60. Steps (a)-(e) can be performed in parallel for different, multiple segments of a gene.

Gene sequencer and method for determining the nucleotide sequence of a chromosome


An electronic metronome includes an adjustable oscillator driving a first frequency divider, a crystal time base driving a second frequency divider for generating a pair of audible frequencies, a standard pitch frequency and reference (time base) frequencies, a frequency counter coupled to the output of the adjustable oscillator for counting the output of the adjustable oscillator, a digital display and display stabilizer circuitry for displaying the count of the frequency counter, a gate driven by the first frequency divider for programmably serially selecting one of the pair of audible frequencies at a rate determined by the output of the frequency divider, a selector switch, three visual indicators, and a programmable counter coupled to the selector switch and visual indicators for providing various sequential time signature displays and an audio amplifier and speaker for providing an audible beat patterns. The metronome may be adjusted to provide a wide range of beats per minute which is displayed on the digital display. Various beats per measure patterns such as single meter, duple meter, and up to and including sextuple meter are displayed in various distinct patterns by the three visual indicators with accompanying distinct audible rhythms.

The present invention relates to metronomes and more specifically to electronic metronomes which provides a digital readout of beats per minute, an audible tick-tock rhythm and various visual pattern displays corresponding to certain available beats per measure time signatures.
Metronomes are constant companions to the music student and musician. The maintenance of constant tempi through practice and inculcation is known to the youngest student and most accomplished professional.
Conventional metronomes are mechanical devices having timing mechanisms which resemble that of an inverted pendulum clock. That is, an escapement mechanism is controlled by a pendulum arm pivoted at its lower extremity which includes a weight longitudinally movable therealong. The selected position of the metronome weight determines the oscillatory frequency of the pendulum and thus the tempo of the metronome. Such a device is generally disclosed in U.S. Pat. No. 3,724,203.
The advent and application of electronic circuitry to the metronome has brought not only significant change to the basic device but also expansion of its capabilities. Metronomes incorporating digital displays of tempo and which produce audible as well as visually perceptible beats are known in the art. For example, U.S. Pat. No. 4,018,131 discloses an electronic metronome capable of providing audibly distinct subdivisions and cross rhythms. No visual indication is provided by the device therein disclosed, however.
Visual outputs are, however, provided in the devices disclosed in U.S. Pat. Nos. 4,014,167 and 4,193,257. In the former patent, a metronome is capable of providing audible and visual display of downbeat and medial beat sound or combinations thereof. In the latter patent, upbeat and downbeat visual indications as well as an audible output which provides emphasis of downbeat are provided. A digital readout of the selected tempo is also displayed.
U.S. Pat. Nos. 4,090,355 and 4,204,400 disclose additional electronic metronomes having distinct downbeat and upbeat displays which vary, for example, by color or duration.
U.S. Pat. No. 3,818,693 discloses a metronome wherein the beat pattern is intended to duplicate that pattern described by a band or orchestra leader's hand. Thus, the face of the metronome includes four spaced-apart displays arranged in a pattern of the quarter hours of a clock face.
Whereas these metronomes individually provide various features such as digital tempo display and various beat pattern outputs, none teach a device which provides the most desirable characteristics, namely, an authentic tick-tock audible output, a digital display and selectable visual beat patterns coupled with a high accuracy time base. Thus, improvements in the art of electronic metronomes are not only possible but desirable.


A magnet primarily for use in MRI applications comprises a pair of poles oriented about a plane of symmetry parallel to each therebetween defining an air gap region, magnetic field sources secured on the surfaces of the poles opposite the air gap that have yokes disposed on them, the yokes connected to each other by returns so that the entire magnet assembly can form a closed magnetic flux circuit to substantially confine the magnetic fields generated by the apparatus in the air gap where an imaging region is formed to place subjects for the purposes of examination. The main assembly being cylindrical in geometry has permanent magnets for magnetic field sources that are composed of two regions, a central disk-like portion magnetized substantially along the axial direction and an outer ring-like region magnetized substantially along the radial direction extending axially to form part of the pole together producing a very efficient and even flux distribution throughout the entire magnet assembly with minimal flux leakage. A further means of reducing flux leakage is incorporated in the yokes which have two sections, a disk-like region and an ring-like section to enclose the permanent magnets. The poles are made of multiple sections with a central disk-like region and an outer ring-like region that is a combination of permanent magnets and high permeability materials. This magnet assembly can achieve 1.0 Tesla or greater magnetic fields for whole-body scanning without saturating the magnet pole and other structures.

1. Field of the Invention
The invention relates to a new class of permanent magnet designs that can generate very strong and highly homogeneous fields for NMR, MRI and MRT use. In particular, the magnet is capable of generating field strengths of 1.0 Tesla or greater and still accommodate whole-body imaging without saturating the pole piece and surrounding magnet structures.
2. Description of the Related Art
In MRI the strength of the NMR signal is proportional to the magnetic field and so the greater the magnetic field the stronger the NMR signal which translates into improved image quality and faster acquisition of image data. For whole-body imaging field strengths greater than 0.5 Tesla were only achieved using superconducting coils typically in cylindrical configurations although recently there have been 1.0 Tesla open configurations as well. However, magnets based on superconducting coil technology require dual cryogen systems and periodic refilling making them expensive to buy and maintain. Consequently, a cheaper alternative is desirable.
As the overall MRI technology progresses demand for permanent magnet based MRI scanners has grown. Most whole-body permanent magnet based scanners are still below 0.5 Tesla and are limited in certain important applications that require greater field strengths. The limitations become severe when the required magnetic field is greater than 0.5 Tesla. First the available permanent magnets of which the strongest today is a Neodymium-Iron-Boron (NdFeB) compound can only produce a limited amount of magnetization—NdFeB compounds are capable of producing magnetic energy densities of up to 50 MGOe. Thus, there is a fundamental limit to how much magnetization these materials can produce and the magnets made from them if they are to be compact in size and weight. Second, the ferromagnetic structures and in particular the poles will saturate rendering the magnet inoperative.
A conventional magnet typically consists of permanent magnet blocks magnetized along the main magnet assembly axis which is cylindrical in configuration and are arranged to create a dipolar field with one section of the permanent magnets forming a North Pole and the other a South Pole. Each permanent magnet group has a yoke which are connected by returns and poles on the opposite sides that together concentrate the magnetic field in an air gap between the two poles where subjects are placed for the purposes of examination. In conjunction with actively shielded gradient coils and very high energy density permanent magnets such as NdFeB, with energy densities of 45 MGOe or greater, these systems can be optimized for energy efficiency to yield designs that can generate magnetic fields up to 0.55 T before becoming unwieldy in aspect ratio or size, weight and saturating the very important poles rendering the design inefficient, the field inhomogeneous, creating eddy current and residual magnetization problems and thermal drift issues.
The main source of the problem in conventional magnets is the poles. By design, these structures are used to create a constant potential surface across the pole-air gap interface whereby magnetic field lines emanating at this interface are perpendicular to the pole surface and create a highly homogeneous and energy efficient magnetic circuit. However, for typical whole-body systems, as the magnetic field strength in the air gap is required to be greater than about 0.4 T, the poles start to saturate making them ineffective or leading to designs that become impractical because they have to be made very thick. Physically, the poles introduce a boundary discontinuity and the magnetic field lines crossing this interface are forced to follow a path that is substantially curved away from the axial direction. At field strengths greater than 0.4 T, a significant part of the magnetic field energy gets concentrated in the poles saturating them and leading to an inefficient design. Moreover, the abrupt change of direction of magnetic field lines at the pole-air gap interface causes more magnetic energy leakage making the field in the air gap inhomogeneous along with many of the other problems already mentioned.
To overcome some of the problems posed by the poles more permanent magnets can be added to increase the magnetic field in the air gap. However, this solution leads to increased inefficiency because the yokes and returns have to be proportionally bigger in order to carry the additional fluxes generated that would otherwise lead to substantial leakage of energy through these structures as well.
In addition to the problems caused by the poles, the yoke and returns are further sources of magnetic energy leakage. In typical designs, there is a substantial flux path connecting the permanent magnets to the yoke and return. To minimize this leakage the returns can be placed further away from the air gap region. However, this increases the overall size, weight and footprint of the magnet.
Consequently, new methodologies are required to make stronger permanent magnet based designs. The canonical permanent magnet system to create a uniform dipolar field most efficiently is the spherical magnet with a vertically oriented uniform magnetization distribution on the surface of the sphere. However, this is a closed system and doesn't easily lend itself for MRI purposes because the subject under examination needs to be able to go in and out of the sphere. The next best solution is a cylindrical system that is infinite in length and has a vertically oriented uniform magnetization distribution on the surface of the cylinder. In practical implementations, the axial length and radial thickness of the cylinder is finite and instead of a continuous magnetization distribution an even and discrete distribution such as a Halbach array or a Magic cylinder is used.
Based on these efficient configurations, an open system can be formed by simply knocking out the middle portions of the magnetization blocks of the Halbach systems. Similar to conventional systems, rotating this system about the vertical axis will sweep out a circular geometry and make it very efficient. However, this system is obtained by breaking the original symmetry of the cylindrical and spherical systems. Therefore, one has to restore as much of the original symmetry to retain the full benefit of the canonical systems. In this invention, many features and variations on this theme have been used to compensate for the loss of symmetry of the Halbach type magnets and to design a system that is as efficient as possible.
Designs based on this approach far exceed current limits of conventional permanent magnet utility and have several novel features not found in previous MRI permanent magnet designs that simultaneously solve many of the drawbacks inherent in conventional designs.