An OFDM receiver generates an initial channel impulse response in response to a received OFDM signal. The receiver determines the time span within the initial channel impulse response in which significant paths are present. An intermediate channel impulse response estimator identifies paths within the initial channel impulse response and generates an improved intermediate channel impulse response. A channel impulse response estimator performs a second non-linear process to generate a channel impulse response. An equalizer responds to the channel impulse response and the OFDM symbol to equalize the OFDM symbol. Metrics are generated that can be used for effectively stopping the second iterative non-linear process.

1. Field of the Invention
The present invention relates to a system and a method for processing communication signals to more efficiently achieve channel estimation, particularly in providing channel estimation in an orthogonal frequency division multiplexing (OFDM) receiver.
2. Description of the Related Art
To increase data rates and mitigate multipath, advanced networks including so-called 4G wireless networks such as WiMAX and LTE (long-term evolution) have adopted variations of the orthogonal frequency division multiplexing (OFDM) waveform for their PHY layer. The PHY layer is the physical, electromagnetic means by which bits of information are transmitted and received over the air or wire. OFDM offers much sought-after bandwidth efficiency, with a built-in mitigation for the multipath of the wireless channels in urban environments. The sensitivities of OFDM transmission are well-understood. The "bit-pump" scheme for the PHY layer has proven successful in digital subscriber line (DSL, wired) OFDM applications. On the other hand, mobile wireless OFDM applications still face challenges to achieve OFDM's designed capacity.
At the core of the practical and theoretical advantages of OFDM is the use of a fast Fourier transform (FFT). The FFT implemented in OFDM can be viewed as analogous to a bank of tuners for Nc-simultaneous radio stations because each of the tones generated by the FFT can be independently assigned to users. The OFDM PHY provides or receives a simultaneous blast, over a short period of time, of bits on each carrier frequency (tone) with a complete, or partial, allocation of carriers to a given user. Making a partial allocation of carriers among different users and aggregating many users within one period is one multiple-access scheme for OFDM. In the case of 10 MHz bandwidth channels, a user can be receiving up to Nc=840 (WiMAX) or 600 (LTE) simultaneous tones, over a very short duration, such as 0.1 milliseconds. These Nc tones per period of time make up an OFDM symbol. The allocation of many users in one symbol is called OFDMA.
Wireless standards usually consist of three important time segments, defined by the bandwidth available and the information's time sensitivity. Symbols are concatenated to define a frame, which is the longest relevant unit of time and for example might be one millisecond. If the standards assign ten symbols to a frame, then the symbol duration is 0.1 milliseconds. Finally, the FFT size and cyclic prefix (CP) duration define the time spacing between samples, so a 1024 point FFT and 128 point CP define a sampling interval of 11 microseconds. Although FFT computations can be comparatively efficient, the FFT size for an exemplary OFDM system is sufficiently large (e.g., 1024 samples in the 10 MHz bandwidth case) that computational demands remain rather high and power consumption remains an important constraint in designing receivers for user handsets.
OFDM systems are more sensitive and have less robust signal acquisition than 3G systems based on code division multiple access (CDMA). The sensitivity of OFDM systems comes from their use of the fast Fourier transform (FFT) to transform incoming signals from the time to frequency domain. The FFT in OFDM systems can deviate from ideal assumptions under very common real-world conditions and receiver implementations. If the assumptions underlying the FFT algorithm fail, cross talk develops between all of the Nc-channels (on Nc carriers) being transmitted. Crosstalk between carriers degrades performance, which in turn causes bit error rates (BER) to increase.
A wireless OFDM handset may receive multiple paths (copies with different delays) of the same signal from a transmission tower ("base station") due to reflections from structures or large water surfaces. This non-line-of-sight reception or multipath causes the signal to be distorted from the flat frequency domain "shape" output by the transmitter. A receiver must compute a filter to restore the signal to its original flat spectral shape; that filter is said to equalize the signal. OFDM receivers perform a critical equalization computation for each OFDM symbol transmitted.
OFDM, unlike most other modulation strategies commonly used in communication systems, can include two equalizers to improve signal quality: a time equalizer (TEQ) and a frequency equalizer (FEQ). Some OFDM applications such as DSL include a time equalizer while others, such as systems that implement current wireless standards, do not demand a time equalizer. All practical OFDM receivers have a frequency equalizer. Whether a receiver includes a time equalizer or only a frequency equalizer, the receiver needs to perform channel estimation to at least initially determine values of the equalizer coefficients before the equalizer can be used to improve the signal quality. Determining the coefficients for frequency equalizers typically is performed in the frequency domain.
An OFDM communication system typically includes an OFDM transmitter that generates radio signals modulated with information such as data generated by a computer network or voice data. The radio signal travels to a receiver over a channel that distorts the radio signal in various ways, including by transmission over multiple paths of different lengths, introducing multiple copies of the radio signal with different offsets and amplitudes in the mechanism known as multipath. Receiver circuitry down converts the received signal to baseband and then analog-to-digital converts that signal to produce the information signal that is subject to OFDM processing. The radio signal is aligned temporally. Following alignment, the signal is processed to remove the cyclic prefix (CP) from the signal. The cyclic prefix is present because OFDM transmitters add a CP of length NCP, which consists of the last NCP samples, to an information signal waveform of length N so that the digital signal that the transmitter converts to analog and transmits is of length N+NCP. An initial step of the receiver's reverse conversion process then is to remove and discard the added NCP cycle prefix samples. Following that step, a serial to parallel conversion element organizes and converts the serial signal into a parallel signal for further processing. The cycle prefix can be removed either before or after the serial to parallel conversion.
After CP removal the parallel data is provided to a fast Fourier transform (FFT) processor that converts the time domain samples s(n) to a set of frequency domain samples Ri(k) for processing. The received OFDM symbol is assumed to be corrupted by the channel, which is assumed for OFDM to introduce amplitude and phase distortion to the samples from each of the carrier frequencies used in the OFDM system. A frequency equalizer (FEQ) applies an amplitude and phase correction specific to each of the frequencies used in the OFDM system to the various samples transmitted on the different frequencies. The FEQ needs an estimate of the channel's amplitude and phase deviations from ideal at each frequency to determine what corrections to apply.
A typical OFDM channel estimator receives and estimates in the frequency domain a channel based on a set of pilot tone locations and received pilot signals. This is termed frequency domain channel estimation or FDCE. The pilot tones (or just pilots) are typically one or two bit symbols dictated by the relevant standards so that the receiver knows the expected pilot locations and values a priori. All FDCE implementations react to the OFDM symbol output by the FFT to extract the received pilot signals. The channel estimate at each pilot may be determined as the amplitude and phase rotation from the ideally expected post-demodulation value of "+1" for each pilot. Any deviation from this "+1" value constitutes the distortion from the channel at that frequency's bandwidth. The value of the channel at the data carrier frequencies can be estimated by interpolating the values obtained at the pilot carrier frequencies. Various improvements on simple channel estimation schemes are known and are conventionally implemented in the frequency domain. The frequency equalizer receives the signals from the fast Fourier transform processor and the channel estimates from the estimator and equalizes the signal. The output of the equalizer typically is provided to a parallel to serial element that converts the parallel outputs of the equalizer to a serial output user signal.
An OFDM symbol is constructed by setting active data carrier values to non-zero values from a prescribed set of values according to the number of bits to be "loaded" into that OFDM symbol. These values are then subjected to an inverse fast Fourier transform (IFFT) to obtain the time-domain samples. The cyclic prefix is appended to the beginning of the symbol by taking a defined number of samples from the end of a symbol's sequence of time-domain samples. The IFFT might, for example, produce 1024 samples. Certain standards select the CP to have length 128. That means the transmitter selects the last 128 samples from the sequence of 1024 samples and pre-pends those samples so that they become the first 128 samples in the transmitted OFDM symbol, which has a total of 1152 samples. Because of this construction, selecting any 1024 samples out of the 1152 samples of the OFDM symbol produces a circular shift on the original 1024 OFDM time domain samples.
In the case of the WiMAX standard, the OFDM symbol can be transmitted on 60 subchannels with 14 active carriers per subchannel, for a total of 840 active carriers, with 4 pilots per subchannel. The locations of the pilots in any given symbol, and therefore subchannel, are prescribed by the standard. OFDM schemes for high-throughput networks seek to minimize the overhead, and this includes the number of training carriers within a symbol. Reducing the number or density of pilots can limit the ability of receivers to efficiently recover information from a signal.
One theoretical advantage of OFDM is that equalization can be performed after the FFT for each received tone individually through a rather simple algorithm. Another advantage that enables OFDM receivers is that equalizer coefficients need only be estimated for each subcarrier that is relevant to the user, a quantity smaller than the FFT size. The values for each equalizer coefficient corresponding to each tone will depend on the estimation of the channel coefficient—termed channel estimation. Like many operations in OFDM receivers, typical OFDM receivers perform channel estimation after the FFT because the channel estimation at that point is performed simply and efficiently based on a user's tone allocation. Because channel estimation is performed after the FFT, the tones will be impacted by FFT and post-FFT distortions, known as inter-carrier interference (ICI). ICI generally manifest through three conditions: 1) errors in frequency tuning; 2) Doppler from mobility; and 3) interference from other cell-sites. OFDM systems accommodate inter-symbol interference by providing a time gap between symbols, so that inter-symbol interference generally is of less concern for OFDM as compared to other wireless schemes.
Any given channel has a well-known limit to its capacity. In current OFDM implementations, there are additional losses in capacity below the expected rates. Channel estimation errors are a principal culprit. Since ICI affects the channel estimation algorithms post-FFT in typical implementations, poor channel estimation leads to inaccurate equalizer coefficients. Increased bit error rate (BER), due to myriad conditions such as demanding channels and poor channel estimation, can be accommodated by reducing the transmitted bit rate offered to a user. In effect, reducing the transmitted bit rate allows for robustness against interference. However, this is a non-linear correction, since the OFDM scheme allows for transmission of two, four or six bits per tone and consequently, under some circumstances, mitigating distortion requires fewer than 2 bits per tone be transmitted, which means the system makes no data available to the user at all.

Non-linear time domain channel estimation in OFDM systems


This invention relates to polyurethane prepolymer containing adhesives that are liquid at room temperature and that do not phase separate under typical storage and use conditions and that can be cured by exposure to moisture or active hydrogen-containing curing agents. The polyurethane prepolymer adhesives exhibit surprisingly good adhesion to plastics such as fiberglass reinforced plastics (“FRP”).

Field of the Invention
This invention relates to polyurethane prepolymer containing adhesives that are liquid at room temperature and that do not phase separate under typical storage and use conditions and that can be cured by exposure to moisture or active hydrogen-containing curing agents. The polyurethane prepolymer adhesives exhibit surprisingly good adhesion to plastics such as fiberglass reinforced plastics ("FRP").
Brief Description of Related Technology
Liquid moisture curable polyurethane adhesives are known. Indeed, Henkel Corporation presently sells and offers for sale liquid moisture curable polyurethane adhesive products under the tradenames Macroplast® UR and Macroplast® SIA, each of which has been met with considerable market success.
Liquid moisture curable polyurethane adhesive can be modified by some additives. For example, plasticizer oils have been used in the past to improve the rheology of such polyurethane adhesive. Adhesion promoters have also been used in the past to improve the adhesion to substrates of such polyurethane adhesive. However, in some instances, use of the plasticizer oil leads to phase separation, which is undesirable.
In the context of hot melt adhesives, which change phase depending on the temperature to which they are exposured, moisture curable polyurethane based materials are known. For instance, Henkel Corporation has been responsible for advances in such technology as defined and claimed for instance in U.S. Pat. Nos. 6,136,136 (Heidler), 6,221,978 (Li), and 6,635,722 (Li).
U.S. Pat. No. 5,786,085 (Tzeng) is directed to and claims a ridge cap formed from an asphaltic foam material comprising (1) a layer of said asphaltic foam material having an upper surface and a lower surface; (2) a layer of granules embedded in said upper surface of said layer of asphaltic foam material, said granules forming a decorative and/or protective layer of said ridge cap; and (3) an elastomeric strip connected to said layer of asphaltic foam material along a central axis of said layer and covered with said granules, where said ridge cap is bendable along said central axis. In the '085 patent, the asphaltic foam is a polyurethane material, and additives such as plasticizers and viscosity reducers are noted as possible reactants
U.S. Pat. No. 5,932,646 (Roberts) is directed to and claims a composition of matter for waterproofing a surface of a wall comprising from about 30 to about 55 parts by weight of a polymeric base, the polymer base including from about 20 to about 45 parts by weight of a hydrocarbon resin, and from about 55 to about 80 parts by weight of an elastomeric copolymer having units selected from styrene, isoprene, butadiene, ethylene, butylene and mixtures thereof where the hydrocarbon resin and the elastomeric copolymer total about 100 parts by weight; and from about 45 to about 70 parts by weight of a solvent system, where the solvent system includes a blend of petroleum distillates and heptane, where the heptane comprises n-heptane, and where the polymer base and the solvent system total about 100 parts by weight.
Although liquid moisture curable polyurethane adhesives have been in industrial usage for several decades, there stands room for improvement. For example, adhesion to plastics such as FRP can be sometimes difficult. Production of such an adhesive also requires high processing temperature, which translates into higher than desired energy costs. The stability of such an adhesive can also stand improvement. It would be desirable to have liquid moisture curable polyurethane adhesives, which can be produced at lower processing temperatures, have improved stability, and have improved adhesion to plastics such as FRP.

Liquid moisture curable polyurethane adhesives for lamination and assembly


The present invention relates to an apparatus and method for polishing semiconductor substrates with improved throughput and reduced foot print. One embodiment of the present invention provides an apparatus for polishing a substrate. The apparatus comprises a base, four polishing stations disposed on the base, two load cups disposed on the base, a first wash station disposed on the base adjacent to the first of the four polishing station, and a carousel rotatable about a carousel axis and supported by the base, wherein the carousel comprises six substrate heads alignable to any of the four polishing stations, the two load cups and the first wash station.

1. Field of the Invention
Embodiments of the invention generally relate to an apparatus and method for polishing or planarization of semiconductor substrates.
2. Description of the Related Art
Sub-micron multi-level metallization is one of the key technologies for the next generation of ultra large-scale integration (ULSI). The multilevel interconnects that lie at the heart of this technology require planarization of interconnect features formed in high aspect ratio apertures, including contacts, vias, trenches and other features. Reliable formation of these interconnect features is very important to the success of ULSI and to the continued effort to increase circuit density and quality on individual substrates and die.
In the fabrication of integrated circuits and other electronic devices, multiple layers of conductive, semiconductive, and dielectric materials are deposited on or removed from a surface of a substrate. Thin layers of conductive, semiconductive, and dielectric materials may be deposited by a number of deposition techniques. Common deposition techniques in modern processing include physical vapor deposition (PVD), also known as sputtering, chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), and electro-chemical plating (ECP).
As layers of materials are sequentially deposited and removed, the uppermost surface of the substrate may become non-planar across its surface and require planarization. An example of non-planar process is the deposition of copper films with the ECP process in which the copper topography simply follows the already existing non-planar topography of the wafer surface, especially for lines wider than 10 microns. Planarizing a surface, or "polishing" a surface, is a process where material is removed from the surface of the substrate to form a generally even, planar surface. Planarization is useful in removing undesired surface topography and surface defects, such as rough surfaces, agglomerated materials, crystal lattice damage, scratches, and contaminated layers or materials. Planarization is also useful in forming features on a substrate by removing excess deposited material used to fill the features and to provide an even surface for subsequent levels of metallization and processing.
Planarization is generally performed using Chemical Mechanical Polishing (CMP) and/or Electro-Chemical Mechanical Deposition (ECMP). A planarization method typically requires that the substrate be mounted in a wafer head, with the surface of the substrate to be polished exposed. The substrate supported by the head is then placed against a rotating polishing pad. The head holding the substrate may also rotate, to provide additional motion between the substrate and the polishing pad surface. Further, a polishing slurry (typically including an abrasive and at least one chemically reactive agent therein, which are selected to enhance the polishing of the topmost film layer of the substrate) is supplied to the pad to provide an abrasive chemical solution at the interface between the pad and the substrate.
The combination of polishing pad characteristics, the specific slurry mixture, and other polishing parameters can provide specific polishing characteristics. Thus, for any material being polished, the pad and slurry combination is theoretically capable of providing a specified finish and flatness on the polished surface. It must be understood that additional polishing parameters, including the relative speed between the substrate and the pad and the force pressing the substrate against the pad, affect the polishing rate, finish, and flatness. Therefore, for a given material whose desired finish is known, an optimal pad and slurry combination may be selected. Typically, the actual polishing pad and slurry combination selected for a given material is based on a trade off between the polishing rate, which determines in large part the throughput of wafers through the apparatus, and the need to provide a particular desired finish and flatness on the surface of the substrate.
Because the flatness and surface finish of the polished layer is dictated by other processing conditions in subsequent fabrication steps, throughput insofar as it involves polishing rate must often be sacrificed in this trade off. Nonetheless, high throughput is essential in the commercial market since the cost of the polishing equipment must be amortized over the number of wafers being produced. Of course, high throughput must be balanced against the cost and complexity of the machinery being used. Similarly, floor space and operator time required for the operation and maintenance of the polishing equipment incur costs that must be included in the sale price. For all these reasons, a polishing apparatus is needed which has high throughput, is relatively simple and inexpensive, occupies little-floor space, and requires minimal operator control and maintenance.
Multiple polishing steps have been used for polishing the substrate to thereby allow improved polishing rate and finish with multiple pad or slurry combinations, hence increasing throughput.
One method provides a main polishing surface and a fine polishing surface in a polishing apparatus. A single polishing head, controlled by a single positioning apparatus, moves a single substrate between the different polishing stations on the apparatus. However, at least one polishing surface is idle at any given time.
Another method provides multiple polishing pads, each pad corresponding to a polishing head, and a substrate handling device moving the substrate being processed among the polishing pads and heads. However, multiple loading and unloading of substrates limits the throughput and also increases the possibility of particle contamination.
Another method of increasing throughput uses a wafer head having a plurality of substrate loading stations therein to simultaneously load a plurality of substrates against a single polishing pad to enable simultaneous polishing of the substrates on the single polishing pad. Although this method would appear to provide substantial throughput increases over the single substrate style of wafer head, several factors militate against the use of such carrier arrangements for planarizing substrates, particularly after deposition layers have been formed thereon. First, the wafer head holding the wafer being polished is complex. To attempt to control the force loading each substrate against the pad, one approach floats the portion of the head holding the wafer. A floating wafer holder necessitates a substantial number of moving parts and pressure lines must be included in the rotating and moving geometry. Additionally, the ability to control the forces pressing each individual substrate against the pad is limited by the floating nature of such a wafer head assembly, and therefore is a compromise between individual control and ease of controlling the general polishing attributes of the multiple substrates. Finally, if any one substrate develops a problem, such as if a substrate cracks, a broken piece of the substrate may come loose and destroy all of the other substrates being polished on the same pad.
Polishing throughput is yet further limited by the requirement that wafers be washed at the end of polishing and between stages of polishing especially when non-compatible polishing solutions are used in different polishing stages. Although washing time has been limited in the past by simultaneously washing multiple wafer head, insofar as the washing requires additional machine time over that required for polishing, system throughput is adversely affected.
Therefore, there is a need for a polishing apparatus which enables optimization of polishing throughput.

This patent is subject to a terminal disclaimer.


An attachable printer for use with a electronic camera having an image sensor which captures an image of a subject onto the image sensor is disclosed. The camera includes electronics coupled to the image sensor for storing a digital image of the subject; a display; and circuitry coupled to the display and responsive to the stored digital image and effective in a first condition for producing a correctly oriented image on the display and in a second condition for producing a mirror image on the display. The printer is effective when connected in operative relationship to the display and having a moveable carriage, and a scanner and an ink jet printhead mounted on the carriage, and being arranged so that as the carriage moves, the scanner scans the mirror image on the display and produces image signals; and the ink jet printhead being responsive to the signals produced by the scanner for producing a correctly oriented image onto the receiver sheet.

It is known in the prior art to provide an electronic camera which uses an area image sensor. Digital images produced from the image sensor are stored in memory and these images can be shown on a display so that the user can determine which image should be stored for use in producing hard copy images. Typically, these images can be stored in a magnetic disk or a compact memory card.
A shortcoming with prior electronic cameras is that the printer is spaced from the camera and must be electrically coupled to digital storage structure within the camera. Such printers are expensive in that the image must be transmitted and stored within a printer. The printer and the camera must contain transmission means and a transmission protocol. Transmission means within the camera increase camera size and cost.
Document scanners that print simultaneously with scanning have been disclosed in prior art. One difficulty in such systems is that an image must be mirrored in the copying process. U.S. Pat. No. 4,839,741 discloses a belt that translates to move a scanning device simultaneous with motion of an ink jet cartridge in an opposite direction using a common belt. The image is mirrored by the counter directional motion of the printhead and scanhead. This process requires incrementally advances of the document on each print/scan cycle.
A portion of U.S. Pat. No. 5,047,870 discloses a photocopy machine that translates a scan/print head in two dimensions to copy a stationary document. As the head moves, a thermal paper is moved with the motion of the scanning head across the source document to create a mirror image. U.S. Pat. No. 5,049,999 does not translate the scanning head in two directions, instead, a source and copy sheet moves in opposite directions to form a non-mirrored image.
U.S. Pat. No. 5,070,410 discloses a common substrate supporting both scanning and ink jet printhead. U.S. Pat. No. 5,070,410 also discloses the use of a plurality of elements sensitive to different wavelengths of light and associated inks that permit for color imaging using such scan means. Furthermore, U.S. Pat. No. 5,070,410 also disclose the use of the apparatus to provide hard copy for unmirrored illuminated slides.

Scanning ink jet printer for electronic displays


An electronic-fuse (e-fuse) circuit includes: an e-fuse array; a control switch, coupled to the e-fuse array, for controlling whether a voltage supply is applied to the e-fuse array in programming; and a close loop feedback circuit, coupled to the control switch and the e-fuse array, for clamping at lease one node voltage of the e-fuse array to a reference voltage, and for controlling the control switch to control a blowing current in programming the e-fuse array.

1. Technical Field
The disclosure relates to an e-fuse (electronic fuse) circuit, and a method for programming the same.
2. Description of the Related Art
Integrated circuits typically include an e-fuse circuit which is capable of being programmed to change an internal setting without changing a design. The e-fuse circuit is used to address a problem that the integrated circuit may not normally operate due to the deviation or defect of the process. By the e-fuse circuit, the deviation of the process is repaired or a defective circuit is replaced, thereby improving the yield of the integrated circuit.
Electrical connection characteristics of the e-fuse used in the e-fuse circuit are changed when a laser beam or an electrical stress is applied to the fuse. E-fuses programmed using electrical stress (an electrical way) are divided into an anti-type fuse in which electrical connection state is changed from an open state to a short state, and a blowing type fuse in which an electrical connection state is changed from a short state to an open state.
There needs an e-fuse circuit which enhances yield, avoids device (for example, a core device used in the e-fuse circuit) reliability issue, and provides wide voltage supply operating range.

E-fuse circuit and method for programming the same


A sled device for permitting transportation of a person and cargo over a variety of surfaces includes a sled including a bottom wall and a perimeter wall that extends upwardly from the bottom wall to define a receiving space of the sled to receive the person and cargo. The bottom wall is slidable along a soft support surface. A front wheel assembly is rotatably coupled to the sled and is rotatable between a deployed position and a stowed position. The front wheel assembly engages and rolls along a hard support surface when the front wheel assembly is in the deployed position. A plurality of rear wheel assemblies is pivotally coupled to the sled and each is pivotable between a lowered position and a raised position. The rear wheel assemblies engage and roll along the hard support surface when the rear wheel assemblies are in the lowered position.

1. Field of the Invention
The present invention relates to convertible sleds and more particularly pertains to a new convertible sled for permitting transportation of a person and cargo over a variety of surfaces.
2. Description of the Prior Art
The use of convertible sleds is known in the prior art. While these devices fulfill their respective, particular objectives and requirements, the need remains for a device that has certain improved features that allow the device to be transported over water and land. Additionally, the device should have wheel assemblies that are stowed away from a bottom wall of the device to inhibit damage to the wheel assemblies when the device is transported across soft support surfaces.


The invention relates to an adsorptive filtering material with biological and chemical protective function, in particular with protective function with regard to both chemical and biological poisons and noxiants, such as chemical and biological warfare agents, the adsorptive filtering material having a multilayered construction comprising a first outer supporting layer and a second outer supporting layer and an adsorptive layer disposed between the two supporting layers, the adsorptive filtering material further comprising at least one catalytically active component, the first outer supporting layer and/or the second outer supporting layer being provided with the catalytically active component. The adsorptive filtering material is particularly useful in NBC protective materials (for example NBC protective apparel) and also for production of filters.

The present invention relates to an adsorptive filtering material with biological and chemical protective function and to its use, in particular for production of protective materials of any kind and also of filters and filtering materials of any kind. The present invention further relates to the protective materials and also filters and filtering materials themselves, produced using the adsorptive filtering material of the present invention.
There are a whole series of materials which are taken up by the skin and lead to serious physical harm (noxae). Examples include the vesicatory Hd (also known as Yellow Cross and mustard gas) and the nerve agent sarin. People likely to come into contact with such poisons must wear suitable protective apparel or be protected against these poisons by suitable protective materials.
There are in principle three types of protective suits: air and water vapor impervious protective suits which are equipped with a layer of rubber which is impervious to biological and chemical poisons and very rapidly leads to a heat build-up for the wearer; air and water vapor pervious protective suits, which offer the highest wear comfort; and finally protective suits equipped with a membrane which allows water vapor to pass through it but not biological and chemical poisons. NBC protective apparel is thus traditionally produced either from impermeable systems (for example suits composed of butyl rubber or suits comprising a membrane) or permeable, air-pervious adsorptive filtering systems based in particular on activated carbon (for example pulverized coal carbon, activated carbon fiber materials or spherocarbon etc).
While air-impervious membrane-equipped suits lead to relatively good protection not only against chemical and biological poisons but also against warfare agents, permeable, air-pervious adsorptive protective suits possess a very good protective effect with regard to chemical poisons, but which often is only inadequate with regard to biological noxiants.
Permeable, adsorptive filtering systems, in particular those based on activated carbon, are therefore often endowed with a catalytically active component by impregnating the activated carbon with a biocidal or biostatic catalyst, in particular on the basis of metals or metal compounds.
Such a protective material is described for example in DE 195 19 869 A1, which contains a multiply, textile, gas-pervious filtering material comprising an adsorptive layer based on activated carbon, in particular in the form of carbonized fibers, the activated carbon being impregnated with a catalyst selected from the group consisting of copper, cadmium, platinum, palladium, mercury and zinc, in amounts of 0.05% to 12% by weight, based on the activated carbon material. The disadvantage with this protective material or filtering system is the fact that impregnation with the catalyst destroys a portion of the adsorptive capacity needed for adsorbing and thus disarming chemical noxiants. The impregnating operation thus has an adverse impact on the performance capability of the activated carbon used. Furthermore, impregnating the activated carbon material is relatively costly and often compromises the manufacturing operation for the activated carbon, in particular the activating step. Moreover, impregnation with the catalyst does not always provide the desired efficacy against biological noxiants or microorganisms. Finally, the impregnating operation requires relatively large amounts of the catalytic metal.
The present invention therefore has for its object to provide an adsorptive filtering material or protective material whereby the above-described disadvantages of the prior art are at least substantially obviated or at least ameliorated. More particularly, such an adsorptive filtering or protective material should be suitable in particular for the production of NBC protective materials of any kind, for example NBC protective apparel and the like, and also of filters and filtering materials.
The present invention further has for its object to provide a permeable, in particular gas- or air-pervious adsorptive filtering or protective material which is effective not only with regard to chemical poisons or noxiants, in particular chemical warfare agents, but also with regard to biological noxiants (for example microorganisms, such as bacteria, viruses and fungi), in particular biological warfare agents.
The problem described above is solved in the realm of the present invention by an adsorptive filtering material. Further, advantageous embodiments of the described adsorptive filtering material are also disclosed.
The present invention further provides for the use of the present invention's adsorptive filtering material for production of protective materials of any kind, in particular of protective apparel, in particular for the civil or military sector, such as protective suits, protective gloves, protective shoewear, protective socks, protective headgear and the like, and of protective covers of any kind, preferably for NBC deployment, and also the thus produced protective materials of the aforementioned kind themselves.
The present invention finally also provides for the use of the present invention's adsorptive filtering material for production of filters and filtering materials of any kind, in particular for removing noxiant, odorant and toxicant materials of any kind, in particular from air and/or gas streams, such as NBC protective mask filters, odor filters, sheet filters, air filters, in particular filters for indoor air cleaning, adsorption-capable supporting structures and filters for the medical sector, and also the thus produced filters and filtering materials of the aforementioned kind themselves.
The present invention accordingly provides in a first aspect of the present invention an adsorptive filtering material with biological and chemical protective function, in particular with protective function with regard to both chemical and biological poisons and noxiants, such as chemical and biological warfare agents, the adsorptive filtering material having a multilayered construction comprising a first outer supporting layer and a second outer supporting layer and an adsorptive layer disposed between the two supporting layers, the adsorptive filtering material further comprising at least one catalytically active component, wherein the first outer supporting layer and/or the second outer supporting layer, preferably the first outer supporting layer or the second outer supporting layer, is/are invested or provided with the catalytically active component. According to the present invention it is accordingly the case that at least one of the two outer supporting layers and preferably only one of the two outer supporting layers is invested or provided with the catalytically active component.
The fundamental idea of the present invention thus consists in endowing adsorptive filtering materials of multilayered construction with an increased or improved protective function with regard to biological noxiants, in particular biological warfare agents, by providing a catalytically active component which—in contradistinction to the prior art—is part of the supporting layer or layers.
The fact that the catalytically active component is part of the supporting layer as opposed to the adsorptive layer provides a multiplicity of advantages. First, costly and inconvenient impregnation of the adsorptive layer, in particular the activated carbon, is obviated. Consequently, the adsorptive capacity of the adsorptive layer, in particular of the activated carbon, is not impaired or reduced by the catalytically active component. Secondly, the manufacturing operation for the adsorptive layer, in particular the activated carbon manufacture, is not impaired by the presence of the catalytically active component. Thirdly, it is simpler in production engineering terms to fit the investment of the supporting layer or layers with the catalytically active component into the production line of the entire manufacturing operation for the adsorptive filtering material, since the coating with the catalytically active component takes place independently of the manufacture of the adsorptive layer, more particularly independently of the activated carbon manufacture.
Moreover, Applicants' studies have shown that, surprisingly, the protective function of the present invention's adsorptive filtering material wherein the catalytically active component is disposed not in the adsorptive layer, but in some other layer (namely  according to the present invention, in the supporting layer), the protective performance is distinctly improved compared with conventional adsorptive filtering materials of the prior art wherein the adsorptive layer itself is impregnated with the catalytically active component. Applicants' tests, carried out according to the relevant prescriptions and standards, have shown that the permeated amount of chemical and biological poisons and noxiants is distinctly reduced in the case of the adsorptive filtering material according to the present invention—compared with conventional protective materials wherein the adsorptive layer is impregnated with the catalytically active component (the comparison being undertaken with comparable systems of catalyst and comparable amounts of catalyst). This is because, in the realm of the adsorptive filtering material of the present invention, the poisons and noxiants to be rendered harmless have to pass through a double barrier in the form of two distinct layers, namely, on the one hand, a layer comprising a catalytically active component which acts in particular against biological noxiants (for example microorganisms, such as bacteria, viruses or fungi and the like), but in certain circumstances also renders harmless, or alternatively may destroy, a portion of the chemical noxiants and poisons, and, on the other, an adsorptive layer for adsorption, or rendering harmless, predominantly of chemical poisons and noxiants, but if appropriate also a portion of the biological toxicants. By virtue of the fact that, in accordance with the present invention, the catalytically active component on the one hand and the adsorptive component on the other are disposed in separate layers, moreover, the residence or contact time with the poisons or noxiants to be rendered harmless is considerably increased compared with conventional adsorptive filtering materials wherein the catalytically active component is disposed in the adsorptive layer itself, so that the protective performance is increased and the number of breakthroughs is reduced. In addition, smaller amounts of catalytically active component are needed.
The protective material of the present invention thus offers effective protection not only with regard to chemical poisons and noxiants, in particular chemical warfare agents ("C weapons" such as sarin, Hd, soman etc.) but also with regard to biological poisons and noxiants ("B weapons", such as viruses, bacteria, fungi, microorganisms, etc, examples being anthrax, smallpox, Ebola, plague, Marburg virus, etc.).
The biological protective function of the adsorptive filtering material of the present invention is comparable to membrane systems, but the gas, in particular air, perviousness or permeability of the adsorptive filtering material of the present invention means that wear comfort is distinctly enhanced over membrane suits on processing into NBC protective suits. But the decisive advantage of the present invention's adsorptive filtering material over membrane systems is that biological noxiants are rendered harmless or decomposed by the adsorptive filtering material of the present invention, so that, after use of the adsorptive filtering material of the present invention, no harmful noxiants remain on the material, whereas in the case of membrane systems of the prior art—which have only one barrier function—the noxiants remain on the surface and still constitute a risk of contamination or endangerment, for example when the protective apparel is being taken off). Moreover, the adsorptive filtering material of the present invention is consequently repeatedly usable without further ado without it having to be decontaminated, since it is constructed to be self-decontaminating so to speak.
Compared with adsorptive filtering materials of the prior art wherein the activated carbon itself is impregnated with the catalytically active component, the protective function offered by the adsorptive filtering material of the present invention is distinctly enhanced—as has shown itself in particular in the lower number of breakthrough rates in the course of Applicant' measurements, and that even in the case of major quantities of challenging chemical and biological poisons and noxiants and even over a prolonged period.
Altogether, the conception of the adsorptive filtering material of the present invention is associated with a multiplicity of advantages, of which the aforementioned advantages may only be mentioned by way of example.
As previously described, the adsorptive filtering material of the present invention has a sandwich-like construction in which the adsorptive layer is so to speak disposed as a core layer between two outer supporting layers or plies.
As previously described, in principle not only the first outer supporting layer but also the second outer supporting layer may be invested/provided with the catalytically active component (i.e. at least one of the two outer layers may be invested/provided with the catalytically active component. However, it is preferable according to the present invention for only one of the two outer supporting layers to be invested/provided with the catalytically active component, and it is preferably the supporting layer which, in the use state, faces the noxiant side that is invested/provided with the catalytically active component. This ensures that, in the use state, the noxiant-containing air stream first passes through the supporting layer comprising the catalytically active component, only then the adsorptive layer and finally the second supporting layer. In the less preferred embodiment, whereby both the supporting layers are invested or provided with a catalytically active component, different catalytically active components may be provided for example for the first outer and the second outer supporting layers. However, all elucidations hereinbelow relate to both the embodiments, i.e. not only to the less preferred embodiment, whereby both the supporting layers are invested or provided with the catalytically active component, but also to the embodiment whereby only one of the two supporting layers is invested or provided with the catalytically active embodiment.
The adsorptive layer provided according to the present invention may be secured, in particular adhered (for example by discontinuous, in particular dot matrix shaped adhesive bonding), to the first outer supporting layer and/or to the second outer supporting layer. As a result, the adsorptive layer is advantageously conjoined, in particular adhered, with the first outer supporting layer and/or with the second outer supporting layer, preferably with the first outer supporting layer and with the second outer supporting layer. However, in principle it is also possible for the individual layers to be all or in part only to be arranged above each other loosely or at least essentially unconjoined.
In an embodiment preferred according to the present invention, the adsorptive layer is based on activated carbon, i.e. the adsorption-capable layer comprises or consists of activated carbon. The activated carbon may be present in the form of activated carbon particles and/or activated carbon fibers.
For example, the adsorptive layer may comprise or consist of discrete particles of activated carbon, preferably in granule form ("granulocarbon") or spherical form ("spherocarbon"). More particularly, in this case the average diameter of the activated carbon particles is <1.0 mm, preferably <0.8 mm, more preferably <0.6 mm. The average diameter of the activated carbon particles is at least 0.1 mm in particular. In this embodiment, the activated carbon particles can be used in an amount of 10 to 500 g/m2, in particular 25 to 400 g/m2, preferably 50 to 300 g/m2, more preferably 25 to 275 g/m2, even more preferably 100 to 250 g/m2, most preferably 125 to 200 g/m2. In particular, activated carbon particles are used that have a bursting pressure of 5 newtons, in particular at least 10 newtons and/or up to 20 newtons per individual particle of activated carbon, in particular activated carbon granule or spherule.
Alternatively, however, the adsorptive layer may also be formed of activated carbon fibers, in particular in the form of an activated carbon fabric, or comprise activated carbon fibers. This embodiment utilizes in particular activated carbon fabrics having basis weights in the range from 10 to 300 g/m2, in particular in the range from 20 to 200 g/m2 and preferably in the range from 30 to 150 g/m2. Useful activated carbon fiber fabrics for the present invention include for example activated carbon fiber wovens, formed-loop knits, laids or composites, in particular based on carbonized and activated cellulose and/or based on carbonized and activated acrylonitrile.
It is similarly possible to combine activated carbon particles on the one hand with activated carbon fibers on the other to form the adsorptive layer.
It is preferable according to the present invention when the activated carbon (i.e. activated carbon particles or activated carbon fibers) used to form the adsorptive layer has an internal surface area (BET) of at least 800 m2/g, in particular of at least 900 m/2g, preferably of at least 1000 m2/g and more preferably in the range from 800 to 2500 m2/g.
It may further be provided that the adsorptive filtering material of the present invention may further comprise at least one top layer, which may typically be disposed on, preferably conjoined with, that side of the first or second outer supporting layer which is remote from the adsorptive layer. Typically, the materials used for the top layer are textile fabrics, in particular wovens, knits, laids, bondeds (batts for example) or nonwovens. Typically, the top layer is disposed such that, in the use state of the adsorptive filtering material of the present invention, it faces the side of the challenging toxicant or noxiant materials, i.e. on that supporting layer which, in the use state, faces the noxiant side. Typically, the top layer is oleo- and/or hydrophobicized, preferably oleo- and hydrophobicized, in particular to achieve a certain aerosol protection and when sizable droplets of noxiant and toxicant materials land on the surface to disperse them on the surface of the absorptive filtering material of the present invention; suitable oleo- and hydrophobicizing agents for this purpose are well known to a person skilled in the art (for example fluoropolymers, such as fluorocarbon resins). The top layer may further be endowed with flame protection (a phosphoric ester for example). The top layer may also be rendered antistatic. The top layer may also be endowed with infrared (IR) reflective properties. Finally, the top layer may also be provided on its noxiant side (i.e. on the outside surface in the use state) with a camouflage print, in particular in the manufacture of NBC protective suits.
In a particularly preferred embodiment, the adsorptive filtering material of the present invention has the following construction: top layer/first outer supporting layer comprising catalytically active component/adsorptive layer/second outer supporting layer. The top layer generally faces the noxiant side in the use state of the adsorptive filtering material of the present invention. It is further possible in this embodiment for the second outer supporting layer to be likewise impregnated with a catalytically active component.
As well as the aforementioned layers, the adsorptive filtering material of the present invention may contain yet other layers, in particular textile plies. These can be disposed above, below or between the aforementioned layers.
The catalytically active component used according to the present invention comprises in particular a catalytically active component having a biostatic and/or biocidal effect, in particular a bacteriostatic or bactericidal and/or virustatic or virucidal and/or fungistatic or fungicidal effect. Typically, the catalytically active component is based on a metal or a metal compound, in particular from the group consisting of copper, silver, cadmium, platinum, palladium, rhodium, zinc, mercury, titanium, zirconium and/or aluminium and also their ions and/or salts, preferably copper and silver and also their ions and/or salts.
Preferably, according to the present invention, the catalytically active component is based on a metal or metal compound, preferably an inorganic metal compound, more preferably a metal oxide. It is similarly possible to combine various metals or metal compounds with each or one another, either in the same supporting layer or alternatively in distinct supporting layers. In an embodiment particularly preferred according to the present invention, the catalytically active component is selected from silver and/or copper, in particular in metallic form and/or in ionic, preferably oxidic form. It is very particularly preferred according to the present invention for the catalytically active component to be selected from the group consisting of Ag, Ag2O, Cu, Cu2O and CuO and also mixtures thereof.
The catalytically active component used according to the present invention is selected such that it retains its catalytic activity for at least five years and preferably for at least ten years when stored under customary conditions. Furthermore, the catalytically active component should also be stable, i.e. storage stable, above 80° C. for a defined period. This prerequisite is fulfilled by the aforementioned compounds, in particular those based on silver and/or copper.
The amount used of catalytically active component can vary within wide limits. In general, the amount used of catalytically active component, based on the first and/or second outer supporting layer, is in the range from 0.001% to 20% by weight, in particular in the range from 0.005% to 10% by weight and preferably in the range from 0.01% to 5% by weight. Based on the adsorptive filtering material as a whole, the amounts of catalytically active component used are of course less. In general, the catalytically active component is used in amounts based on the adsorptive filtering material as a whole ranging from 0.0001 to 10% by weight, in particular from 0.001% to 5% by weight and preferably from 0.002% to 2% by weight. It can none the less be envisaged according to the present invention to depart from the aforementioned amounts, for a particular application or on a one-off basis, without going outside the realm of the present invention.
The first outer supporting layer may be at least essentially sheetlike or at least essentially two-dimensional. In particular, the first outer supporting layer is a textile fabric, e.g. a woven fabric, a knitted fabric, a laid fabric, a bonded fabric (a batt for example) or a nonwoven. In general, the textile fabric of the first outer supporting layer has a basis weight in the range from 10 to 150 g/m2, in particular in the range from 10 to 100 g/m2, preferably in the range from 15 to 75 g/m2, more preferably in the range from 20 to 60 g/m2 and most preferably in the range from 25 to 50 g/m2. The second outer supporting layer is also generally at least essentially sheetlike or at least essentially two-dimensional. In particular, the second outer supporting layer is a textile fabric, in particular a woven fabric, a knitted fabric, a laid fabric, a bonded fabric (a batt for example) or a nonwoven, wherein the textile fabric of the second outer supporting layer generally has a basis weight in the range from 10 to 150 g/m2, in particular in the range from 40 to 120 g/m2 and preferably in the range from 60 to 120 g/m2.
In principle, identical materials can be used to form the first and second outer supporting layers. However, it is generally preferable to use different materials, in particular textile fabrics having different basis weights and/or different fibers and/or different properties.
For example, the first and/or second outer supporting layers may be a textile fabric consisting of natural and/or manufactured fibers, preferably manufactured fibers.
It is preferable according to the present invention- for the first and/or second outer supporting layers to be a textile fabric comprising or composed of natural and/or manufactured fibers, preferably manufactured fibers, preferably from the group consisting of polyamides, polyesters, polyolefins, polyurethanes, polyvinyl (for example polyvinyl alcohols) and/or polyacrylic.
As previously described, the first and/or second outer supporting layers are constructed as a textile fabric. The catalytically active component is generally incorporated in or permanently conjoined with the supporting layer or the textile fabric of the supporting layer in question, in particular the fibers, threads, yarns, filaments or the like forming the fabric. Depending on the chemical nature of the fibers, threads, yarns, filaments or the like, the incorporation of the catalytically active component can be effected by different processes, for example by spinning, extrusion, impregnation, chemical treatment processes (for example by impregnation with subsequent oxidation/reduction), plasma-chemical treatment processes (for example sputtering) or the like. A person skilled in the art is sufficiently familiar with this from the prior art.
In principle, the first and/or second outer supporting layers, in particular the supporting layer which faces the noxiant source in the use state, may also be provided with a hydrophilic or hydrophobic finish. In general, the first and/or second outer supporting layers have a cross-sectional thickness in the range from 0.05 to 5 mm, preferably in the range from 0.1 to 1 mm and in particular in the range from 0.2 to 0.5 mm. Furthermore, the first and/or second outer supporting layers generally have a good gas or air transmission rate, in particular of at least 1000 l·m−2·s−1, in particular at least 2000 l·m−2·s−1, preferably at least 3000 l·m−2·s−1 and more preferably at least 3500 l·m−2·s−1 at a flow resistance of 127 pascals.
With regard to the durable finishing or endowment of textile fabrics with biocidal or biostatic catalytically active components and the corresponding manufacturing operation reference may be made by way of example, purely illustratively, to the following printed publications, whose disclosure in this respect is hereby incorporated herein by reference: WO 01/74166 A1 or the resulting European patent EP 1 272 037 B1 as well as WO 98/06508 A1, WO 98/06509 A1, US 2005/0049370 A1, US 2003/0198945 A1, US 2005/0048131 A1, WO 00/75415 A1, WO 01/81671 A2 and WO 03/086478 A1.
Textile fabrics useful for the purposes of the present invention and being invested or provided with a biostatic or biocidal catalytically active component and useful as outer supporting layers in the realm of the present invention are also commercially available, for example from Cupron Corporation, New York (USA), Foss Manufacturing Company Inc., Hampton, N.H. (USA) or Noble Fiber Technologies, Clarks Summit, Pa. (USA).
As previously described, the adsorptive filtering material of the present invention is gas pervious, in particular air pervious, and/or water pervious and/or water vapor pervious. This provides excellent wear comfort on processing into NBC protective suits.
In general, the adsorptive filtering material of the present invention has, at a flow resistance of 127 pascals, a gas or air transmission rate of at least 50 l·m−2·s−1, in particular at least 100 l·m−2·s−1, preferably at least 200 l·m−2·s−1, more preferably at least 500 l·m−2·s−1 and most preferably at least 600 l·m−2·s−1, and/or up to 10 000 l·m−2·s−1.
In general, the adsorptive filtering material of the present invention has an overall basis weight in the range from 150 to 1000 g/m2, in particular in the range from 200 to 800 g/m2, preferably in the range from 250 to 600 g/m2 and more preferably in the range from 300 to 500 g/m2, in particular when the overall cross-sectional thickness of the adsorptive filtering material of the present invention ranges from 0.1 to 10 mm, in particular from 0.2 to 5 mm and preferably from 0.5 to 1.0 mm.
To increase wear comfort on processing into NBC protective apparel, the adsorptive filtering material of the present invention should have a water vapor transmission rate of at least 5 l/m2 per 24 h, in particular at least 10 l/m2 per 24 h, preferably at least 15 l/m2 per 24 h, more preferably at least 20 l/m2 per 24 h and most preferably at least 25 l/m2 per 24 h.
To ensure a good protective effect, the adsorptive filtering material of the present invention generally has a barrier effect with regard to chemical warfare agents, in particular bis[2-chloroethyl] sulphide (mustard gas, Hd, Yellow Cross), determined by method 2.2 of CRDEC-SP-84010, permitting permeation of not more than 4 μg/cm2 per 24 h, in particular not more than 3.5 μg/cm2 per 24 h, preferably not more than 3.0 μg/cm2 per 24 h and more preferably not more than 2.5 μg/cm2 per 24 h.
Further advantages, properties, aspects and features of the present invention will become apparent from the following description of an operative example depicted in the drawings.

Adsorptive filtering material having biological and chemical protective function and use thereof


The invention provides an environmentally friendly renewable energy harvesting system for harvesting wind energy on a frozen surface, as in cold weather climatic regions associated with higher latitudes or higher altitudes, with snow or ice surfaces. A plurality of ski, skate or runner supported wings or sails are connected together to form a wind energy harvesting system, and capture wind energy by appropriate setting of wing or sail angles of attack so as to drive a cyclic motion that in turn can drive energy capture means such as electric generator means. The invention thus provides a wind energy harvesting system which is supported by a frozen surface, which includes fluid-foil means for interfacing with an air current such as a wind and which includes energy harvesting means utilizing periodic motion of the fluid-foil means for capturing wind energy and converting it into usable energy in a desired form such as electricity. The present invention is intended to provide devices, methods and systems for harvesting renewable energy which can be efficient and cost-effective for small-scale, medium-scale and large-scale applications, to provide real and substantial benefits to meet local energy needs while also more broadly serving humanity and our global environment.

As the World's human population grows and as the economic prosperity of that population grows, the energy demand of that population also grows. With limited availability of oil reserves, there is a growing need for the conception, development and deployment of cost-effective and large-scale renewable energy alternatives. The continued use of fossil fuels to meet current and emerging energy needs also has very negative environmental consequences, including massive emissions of pollutants and exacerbation of global warming and climate change. This provides further strong motivation for cost-effective, large-scale renewable energy alternatives.
The Sun provides enormous quantities of energy to the World every second, and that unlimited and clean renewable energy can be found in harvestable form both directly as solar energy and indirectly as wind energy.
In some cold weather climes such as Alaska, Northern Canada, Kalaallit Nunaat, Northern Russia, Scandinavia, Antarctica and Sub-Antarctic regions, local habitations require substantial energy for heat and light during very cold and dark winter seasons. It would be highly beneficial to use wind energy to meet these energy needs with a renewable local source, since direct solar energy is not a viable alternative in high latitude winter seasons. The use of efficient wind power in such climes will not only meet energy hunger in these locales, but do so without any greenhouse gas emissions and without any local thermal powerplants dumping heat and greenhouse gases into what may be amongst the most vulnerable locales for the adverse effects of global warming—with these locales being most susceptible to greenhouse gas and global warming induced ice and snow melting, and the consequent long term adverse effect of increasing ocean water levels on a global scale.

Wind energy harvesting system on a frozen surface


According to some aspects, a system configured to facilitate imaging an infant using a magnetic resonance imaging (MRI) device is provided herein. The system comprises an infant-carrying apparatus comprising an infant support configured to support the infant and an isolette for positioning the infant relative to the MRI device, the isolette comprising: a base for supporting the infant-carrying apparatus; and a bottom surface configured to be coupled to the MRI device. In some embodiments, the infant-carrying apparatus further comprises at least one radio frequency (RF) coil coupled to the infant support and configured to be coupled to the MRI device to detect MR signals during imaging performed by the MRI device. A method for positioning an infant relative to an MRI device using an infant-carrying apparatus and isolette is further provided herein.

Magnetic resonance imaging provides an important imaging modality for numerous applications and is widely utilized in clinical and research settings to produce images of the inside of the human body. MRI is based on detecting magnetic resonance (MR) signals, which are electromagnetic waves emitted by atoms in response to state changes resulting from applied electromagnetic fields. For example, nuclear magnetic resonance (NMR) techniques involve detecting MR signals emitted from the nuclei of excited atoms upon the re-alignment or relaxation of the nuclear spin of atoms in an object being imaged (e.g., atoms in the tissue of the human body). Detected MR signals may be processed to produce images, which in the context of medical applications, allows for the investigation of internal structures and/or biological processes within the body for diagnostic, therapeutic and/or research purposes.
MRI provides an attractive imaging modality for biological imaging due to the ability to produce non-invasive images having relatively high resolution and contrast without the safety concerns of other modalities (e.g., without needing to expose the subject to ionizing radiation, e.g., x-rays, or introducing radioactive material to the body). Additionally, MRI is particularly well suited to provide soft tissue contrast, which can be exploited to image subject matter that other imaging modalities are incapable of satisfactorily imaging. Moreover, MR techniques are capable of capturing information about structures and/or biological processes that other modalities are incapable of acquiring. However, there are a number of drawbacks to MRI that, for a given imaging application, may involve the relatively high cost of the equipment, limited availability and/or difficulty in gaining access to clinical MRI scanners and/or the length of the image acquisition process.

Systems and methods for magnetic resonance imaging of infants


A musical notation system is provided wherein the twelve pitches of the 12-TET tuning system are represented by horizontal lines placed at the top, center and bottom of four different reference heads. Pitches, intervals chords and scales degrees are named by the positions of these lines at the reference heads and by the relationship between them. Assistant is provided to performers by representing the correlation between these reference heads and positions or keys in the musical instruments as well as a method to aid identify intervals, scale degrees and pitches. Relative note-on is represented in a timing row with demarcation of beats and measures; note-off is represented by the end of the lines as a proportional indication of the duration of sound.

Computers are great tools for music, when properly commanded they are extraordinary performers of musical instruments, they can also help us in the creation, production and analysis of music.
The Standard Music Notation (SMN) is one of the means used as an interface to communicate with them because it is the universally known and widely accepted notation system, however it is limited and laborious for this task since it evolved long before this technological era and was not intended at all for those purposes, on the other hand the languages such as CAL, encoding systems or files formats such as MIDI that have been created for computers and music are very powerful but unsuitable for human performance or the traditional musical practice.
The piano roll notation is widely used by computer sequencers to display and edit as-performed timing information in a graphical way but it is also unsuitable for human performance and lacks of theoretical support.
The Standard Music Notation is the result of several centuries of evolution, then intended to represent music based on exact-integer-ratio tuning concepts and diatonic scales; it has been an indissoluble part of the theory of music, together they followed and supported the then tuning standard as it struggled to develop, alone the way tuning system, notation and theory formed a perfect and solid braid that could not be broken or significantly modified by the time the battle for temperament ended.
As a result of that battle we have a theoretically simpler and ingeniously well-calculated tuning system, which was slowly assimilated, and treated as a modification of the fading system. This made possible that we could merge the new tuning system with the existing notation and theoretical support, and continue using them even when that harmony or concord with notation and theory do not exist with the twelve-tone equal temperament system (12-TET).
Consequentially we were forced to go on thinking of music through the theory and concepts created to support another tuning system, not with a proprietary one, we could go on this way for ever but the huge musical illiteracy and semi-literacy disproportion that we have today will also remain the same.
Or we could take advantage of the much simple concept of the current standard that would represent to music theory, music perception and in general to the musical practice the equivalent of what equal temperament did to performance in the fixed tone musical instruments many years ago.
We gave a solid forward step adopting the 12-TET as a standard, sacrificing a little bit of beauty to get a lot of functionality and thanks to technology we are ready for the next necessary step in the same direction and consolidate a complete proprietary system for the current tuning standard and the musical practice and music literacy could be for the masses.
There have been many proposals to modify the SMN focusing on the representation of music alone to make easier reading and playing by eliminating the so called unnecessary complications of the SMN; however there are also unnecessary complicated theoretical concepts related to those of representation when some notes are considered accidentals of another and they are not anymore.
It has almost been exhausted variants of the lines and spaces idea, using a variety of resources to represent sharps and flats but keeping the concept alive or do not provide a proprietary theoretical support.
Besides simplification for reading and playing, a modern notation system should also form a solid braid with a proprietary theoretical support for the 12-TET, so that we could have the possibility of completely get rid of unwanted and complicated legacy, it should exceed the possibilities of the SMN and be oriented to technology.
As language music belongs to everybody, so should be the possibility of literacy which is the right way to the musical practice, not necessarily as a profession, to achieve this, a complete alternative solution is not an option, it is the only way.

Proprietary music rotation supporting the equal temperament tuning system


A heater assembly for a heat engine designed to utilize solar energy and heat produced by combustion of a fuel such as natural gas. A receiver housing allows concentrated solar energy to be directed through a receiver aperture into a receiver chamber. Inner and outer arrays of heater tubes within the receiver chamber absorb the solar energy and transfer heat to working fluid in the heater tubes. A burner within the housing produces combustion gases which circulate past the heater tubes and transfer heat to the working fluid. The heater tubes form an opaque surface to solar energy and have uniform gaps which allow heated fluid to be passed between adjacent heater tubes. A precise three-dimensional mathematical description for the centerlines of the heater tubes which maintains uniform gaps between adjacent heater tubes is disclosed.

This invention is related to a heater assembly for a heat engine designed to utilize heat from two distinctly different energy sources and particularly to a heater assembly for a heat engine designed to utilize both solar energy and heat produced by combustion of a fuel such as natural gas.
Heat engines, such as Stirling cycle engines, are capable of converting heat in a working fluid to mechanical output energy. Heat engines are typically coupled to an electrical generator, which converts the mechanical output energy into electricity, or to a device that utilizes the mechanical output energy, such as an irrigation pump or manufacturing equipment. Heater assemblies are the components of heat engines used to transfer heat from an external heat source, such as the sun or a fuel combustor, to an internal working fluid circulating within the heat engine, such as helium or hydrogen. The working fluid undergoes a thermodynamic cycle within the heat engine that converts a portion of the heat energy in the working fluid into mechanical output energy.
One primary application for heat engines is the conversion of solar energy into electricity. In these applications, the heat engine is typically coupled with a solar concentrator and an electrical generator. The solar concentrator is generally a parabolic dish covered with a reflective material, such as glass mirrors, which reflect incident solar radiation and focus this energy toward an energy receptor, which is typically located inside a receiver chamber of a heater assembly attached to the heat engine. The heater assembly typically includes a receiver housing, which forms the receiver chamber and has a receiver aperture or opening which allows the inside of the receiver chamber to be insolated, i.e. exposed to the solar radiation reflected by the solar concentrator. An array of heater tubes attached to the heat engine are located within the receiver chamber and the working fluid circulates through them. The heater tubes absorb the solar radiation and increase the temperature of the working fluid, which is then circulated into the other components of the heat engine where this heat energy is converted into mechanical energy.
A great deal of commercial interest has been expressed in developing large fields of solar powered electrical generators to supply additional quantities of electricity needed during peak electrical demand periods. Peak demand periods for electrical service typically occur during daylight hours during the summer, due in large part to the electrical demands of air conditioning equipment. Because it is during these periods when solar powered electrical generators are typically able to generate maximum quantities of electricity, solar powered electrical generators offer a unique source of electricity for utility companies trying to plan for these fluctuations in electrical service demand.
Utility companies are interested in being environmentally sensitive by using sources of renewable energy, such as solar energy, and reducing the generation of pollutants associated with typical fossil fuel and nuclear power electrical generation systems. They are also interested in reducing the costs associated with constructing, operating and eventually dismantling additional nuclear or fossil fuel powered electricity generating facilities. Fuel costs, particularly the costs of petroleum-based fossil fuels such as fuel oil, have widely fluctuated in the past and utility companies are interested in developing sources of energy that are less subject to these price fluctuations. Fields of solar concentrators combined with Stirling cycle engines connected to electrical generators are currently being evaluated for these types of electricity generation applications.
A significant problem with the vast majority of solar powered electrical generation systems, however, is that they are powered solely by solar energy and solar energy is inherently intermittent. Solar collectors incorporating photovoltaic cell technology, for instance, are unable to utilize any source of energy other than solar energy to produce electricity. Solar energy is inherently intermittent because it is both periodic, because of the diurnal day/night cycle, and random, because of sporadic and often protracted cloudiness that is found virtually everywhere on earth. Even the sunniest areas of the southwest U.S., such as Death Valley, Calif., have an average cloudiness of approximately twenty percent, and this cloudiness can persist for several days in a row. Solar powered electrical generation systems are generally inoperable during these persistently cloudy, overcast periods. Because the total solar energy reaching the ground on a cloudy, overcast day may be one tenth or less of the solar energy reaching the ground on an clear day with no haze or smog, the electricity produced by any type of electricity generating solar collector will depend, in significant part, on the cloudiness of the region the solar collector is installed in. Utility companies and other entities utilizing solar collectors to collect solar energy must therefore constantly factor in a large degree of uncertainty regarding the availability of the power from these systems as well as prepare for the possibility of receiving no power at all from these systems for periods of up to several days in a row.
In addition, extreme weather conditions and maintenance requirements reduce the operating efficiency of typical solar energy collection systems. Thunderstorms, hail, wind blown debris, and high winds can seriously damage solar collection systems. To prevent this type of damage, solar collectors may be inactivated during extreme weather conditions, such as by covering the solar concentrator or rotating the concentrator into a downward facing stowed position. When cleaning or repairing the reflecting surface of a solar concentrator during daylight hours, the concentrator will typically be pointed away from the sun to reduce the possibility of injuring a maintenance worker or damaging the equipment.
To compensate for these fluctuations in power output, many operators of solar powered electrical generation equipment have installed separate fossil-fuel fired backup generation systems or costly, complex and inefficient heat storage systems. The cost and complexity of installing and operating these types of alternative power generation or heat storage systems have significantly reduced the commercial viability of many types of solar powered electrical generation systems.
The inventive heat engine heater assembly has been designed to utilize concentrated solar energy when this energy is available, and to utilize heat produced by combustion of a fuel, such as natural gas, when solar energy is not available. In this way, the hybrid powered electrical generation system is available to produce electricity during cloudy periods, at night, during periods of extreme weather and while maintenance is being performed on the solar concentrator. The inventive heater assembly has been designed to allow the heat engine to be rapidly changed from being solar powered to being combustion powered, and vice versa.
Stirling cycle engines are the primary type of heat engine being evaluated for commercial solar powered electrical generation systems. Stirling cycle engines offer very high thermal efficiency as well as long service free lives. The heat engine used in connection with the inventive heater assembly could include Stirling cycle engine designs and components previously developed by the Assignee of the present invention, Stirling Thermal Motors, Inc., including those described in U.S. Pat. Nos. 4,707,990; 4,715,183; 4,785,633; and 4,911,144, which are hereby incorporated herein by reference.
In contrast to most internal combustion engines, heat engines are typically able to utilize heat from a variety of sources and are not particularly sensitive to the quality of the heat provided. In many cases, the only change required to change heat sources for a heat engine is to install a heater assembly that has been optimized for that particular type of heat source. The internal components of the heat engine may be identical or extremely similar for a wide spectrum of alternative heat sources.
The inventive heater assembly, however, eliminates the need to replace the heater assembly when changing heat sources from solar energy to fuel combustion and vice versa because the heater assembly has been designed to utilize both sources of heat.
The heater assembly incorporates inner and outer heater tube arrays, a receiver housing having a receiver cavity and forming a receiver aperture which allows the receiver cavity to be insolated, a cover for sealing off the receiver aperture, a fuel combustor and a preheater which warms the intake air with heat from the exhaust gases.
The heater tubes arrays are positioned in nested pair of inner and outer arrays that have modified inverted conical frustrum shapes. The individual heater tubes are twisted or swirled in such a manner that identical gaps are maintained between adjacent heater tubes throughout their runs. The inner array of heater tubes connects a number of cylinder extension manifolds to a number of heater tube heads. The outer array of heater tubes connect the heater tube heads to a number of regenerator housing manifolds. Separate heater tubes extend between a cylinder extension manifold and a heater tube head and between a heater tube head and a regenerator housing manifold. Passageways in the heater tube head allow working fluid to flow from the cylinder extension manifold, through the inner array of heater tubes, through the heater tube head, through the outer array of heater tubes and enter the regenerator housing manifold, and vice versa. In the double acting Stirling cycle engine embodiment of the heat engine described herein, the working fluid is constantly shuttled back and forth between the cylinder extension manifolds and the regenerator housing manifolds as the engine operates.
A common design problem associated with the design of a heater assembly for a Stirling cycle engine or other heat engine is how to arrange a plurality of heater tubes emanating from a smaller inner circle of a given radius, r.sub.o, and going to a circle of larger radius, r.sub.f, so that the gap between adjacent tubes is uniform throughout their run. In a direct flame heater head, the uniformity of the gap is important for to obtain desirable external heat transfer characteristics. It is desirable to heat the heater tubes and associated components as evenly as possible to reduce the formation of expansion stresses on the components that can lead to component failures. For a direct-illumination solar receiver, it is advantageous to maintain line contact between adjacent tubes over their entire effective length. This line contact relationship allows a maximum amount of energy to be received for any given set of heater tubes.
When the base circle and the final circle are on the same plane, a constant gap can be obtained by tubes whose centerlines form involutes. Involutes are plane curves formed by the paths of equally spaced points on a line tangent to the root circle as the line is rolled without slip on the circle. A problem arises, however, when there is an axial separation between the base circle and the final circle. When the plane involutes are projected onto an axially symmetric surface between the two circles, say a conical frustrum, the projections are space-curves with gaps between adjacent curves which are, in general, not uniform.
A one-parameter family of axially symmetric surfaces is disclosed herein upon which the space-curves which are projections of plane involutes maintain a uniform gap. These space-curves are particular projections of plane involutes onto a conical frustrum which maintain a uniform gap between adjacent curves.
The inventive heater assembly incorporates a pair of these novel heater tube arrays that are nested closely together to provide an opaque surface to solar radiation. Each member of the outer array of heater tubes is centered within the gap between adjacent members of the inner array of heater tubes when viewed from the central axis of the heater tube arrays. In this way, uniform gaps are also obtained between each member of the outer array and the two closest members of the inner array, thereby further enhancing the heat transfer characteristics of the array when operating in the combustion mode. In addition, the members of the outer array have apparent areas which are the same or larger than the apparent areas of the gaps between adjacent members of the inner array when viewed from the central axis of the heater tube arrays. In this way, the receiver tube arrays present an opaque surface to solar radiation, thereby enhancing the heat transfer characteristics of the array when operating in the solar energy mode and reducing the "dead" area caused when a member of the inner heater tube array shades a member of the outer heater tube array.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings.


Integrated circuits and fabrication methods are provided. The integrated circuit includes: a varying gate structure disposed over a substrate structure, the varying gate structure including a first gate stack in a first region of the substrate structure, and a second gate stack in a second region of the substrate structure; a first field-effect transistor in the first region, the first field-effect transistor including the first gate stack and having a first threshold voltage; and a second field-effect transistor in the second region, the second field-effect transistor including the second gate stack and having a second threshold voltage, where the first threshold voltage is different from the second threshold voltage. The methods include providing the varying gate structure, the providing including: sizing layer(s) of the varying gate structure with different thickness(es) in different region(s).

Different semiconductor devices may be fabricated to have one or more different device characteristics, such as threshold voltage, switching speed, leakage power consumption, etc. Multiple different designs may each provide optimization of one or more of these characteristics for devices intended to perform specific functions. For instance, one design may have reduced threshold voltage to increase switching speed for devices providing computational logic functions, and another design may have increased threshold voltage to decrease power consumption for devices providing memory storage functions. A system using multiple discrete devices, each optimized for different functions, will result in greater system complexity, increased system footprint, and added system cost.

Integrated circuits with varying gate structures and fabrication methods


This invention relates to pyrrolocarbazole derivatives according formula I wherein R1, R2, R7, R8, R9, X and Y are as defined in the specification wherein said derivatives specifically inhibit one or both of the checkpoint kinases Wee1 and Chk1

The proper orchestration of the steps required for orderly progression of the cell through the cell cycle requires a number of signaling pathways within cells. Many of these pathways utilize protein kinases to effect the transmission of crucial signals at the appropriate time and intracellular location. Cell cycle kinases are naturally occurring enzymes involved in regulation of the cell cycle which is generally divided into four segments: G1 (gap1), S (DNA systhesis), G2 (gap 2) and M (mitosis). Some of these kinases are responsible for inhibiting the cell's normal progression through cell division, while others are normally active in promoting the progression of cells through the cell cycle leading to cell division. Increased activity or temporally abnormal activation of these kinases has been shown to result in development of tumors and other proliferative disorders.
One of the protein kinases involved is a tyrosine specific kinase, Wee1, that has as its substrate another kinase complex called Cdc2/cyclinB. Wee1 kinase is a regulatory kinase that has Cdc2/cyclinB as its substrate and when Wee1 is active, it phosphorylates a specific tyrosine (Tyr15) on Cdc2 that causes an inactivation of the Cdc2/cyclinB complex which in turn results in a pause or checkpoint in the cell cycle at the G2 and M transition. The kinase activity of Cdc2/cyclinB is absolutely required for cells to progress through the G2 stage of the cell division cycle to the M (or mitotic) phase where two daughter cells are formed from the division of the parent cell. Under normal circumstances, as cells are progressing through the cell cycle, the Cdc2/cyclinB complex is assembled in late S phase and through G2. Normally, Wee1 is active and thus phosphorylates the Cdc2/cyclinB complex until the end of G2 when all of the necessary components have been synthesized for the entry of cells into M phase. Wee1 activity then diminishes, a phosphatase removes the inhibitory phosphorylation from Tyr15 of Cdc2/cyclinB, the complex becomes activated and cells move into M phase where the replicated DNA is divided and the daughter cells are formed. Inhibition of Wee1 results in no inhibitory phosphorylation of Tyr15 on Cdc2/cyclinB and the potentially inappropriate and premature entry of the cell into mitosis.
In addition to regulation of the transition of cells between the different phases of the cell cycle under normal conditions, the cell cycle transitions are regulated in response to damage to DNA presumably giving cells opportunities either to repair potentially genotoxic DNA damage before replication using a damaged DNA template or to permanently exit the cell cycle and die.
Another kinase of interest named Chk1 participates in this DNA damage dependent signaling pathway by phosphorylating a phosphatase called Cdc25C which when itself is active and co-localized with Cdc2/cyclinB in the nucleus, dephosphorylates Tyr15 and causes the activation of the Cdc2/cyclinB complex. The Chk1 mediated phosphorylation of Cdc25C causes Cdc25C to be exported from the nucleus at which point it is no longer able to dephosphorylate and thus activate Cdc2/cyclinB. Therefore, if Chk1 is active (in response to DNA damage) it will indirectly contribute to the inactivation of Cdc2/cyclinB (whose activity is required for progression into M phase) through the preservation of the inactivating phosphorylation of Tyr15 on Cdc2/cyclinB. Conversely, inhibition of Chk1 would result in the dephosphorylation of Cdc2/cyclinB by the phosphatase Cdc25C in the nucleus (not exported to the cytoplasm since it is not phosphorylated by Chk1) and the consequent activation of Cdc2/cyclinB with the accompanying entry of the cells in mitosis.
Inhibition of Wee1 or Chk1 or both kinases in the presence of DNA damaged by conventional DNA-directed chemotherapeutic agents or by radiation presents an opportunity to utilize cellular regulatory pathways to inappropriately and prematurely cause cells to progress into M phase. Such cells may be less likely to survive and further divide since the commitment to M phase was made in the presence of potentially catastrophically damaged DNA (Alan J. Kraker and Robert N. Booher, "New Cell Cycle Targets,", Ann. Rep. Med. Chem., 1999; 34:247–256).
Small molecule inhibitors of Wee1 kinase have been reported, WO 0119825 and Cancer Res. (2001), 61(22), 8211–8217. Small molecule inhibitors of Chk1 kinase have also been reported W00016781, Cancer Res. (2000), 60(3), 566–572.
Pyrrolocarbazole derivatives are known to have inhibitory activity against Protein kinase c and anti tumor activity (U.S. Pat. No. 4,912,107) but compared to the compounds of the present invention, the compounds disclosed in U.S. Pat. No. 4,912,107 have very low checkpoint kinase abrogator activity. Pyrrolocarbazole derivatives are also known to stimulate platelet production (WO96/28447) and to promote thrombopoiesis (WO9809967). EP 0695755 discloses another pyrrolocarbazole derivative having Protein kinase c activity. U.S. Pat. No. 5,166,204 discloses antitumor isoindole derivatives having a linkage or lower alkylene group bonded to the 2 and 3 or 3 and 4 of a carbazole skeleton. U.S. Pat. No. 5,728,709 discloses pyrrolocarbazole derivatives that stimulate platelet production. WO01/85686 also discloses pyrrolocarbazole derivatives.
However, there are no reports that any type of pyrrolocarbazole inhibits either Wee1 kinase or Chk1 kinase. Nor have there been any reports that any type of pyrrolocarbazole inhibits both Wee1 kinase and Chk1 kinase.

Inhibitors of checkpoint kinases (Wee1 and Chk1)


In a separate linear encoder, a scale is further provided with an ABS track that is arranged in parallel with an INC track and a detection head includes an ABS detection portion that reads the ABS track. The separate linear encoder includes a calculation portion that obtains a yaw angle of the detection head with respect to a scale based on a gap between an INC detection portion and an ABS detection portion and a difference amount between a position value of the INC track, which is detected by the INC detection portion, and a position of the ABS track, which is detected by the ABS detection portion. The calculation portion also obtains a signal strength based on two-phase sine wave signals that are output from the INC detection portion. The separate linear encoder further includes a display device that displays a plurality of yaw angles and the signal strengths corresponding to the respective yaw angles.

In prior art, a separate linear encoder is known. The separate linear encoder has a scale that is provided with an incremental (INC) track (or an absolute (ABS) track), which constitutes a main track, and a detection head that includes an INC detection portion (or an ABS detecting portion), the detection head being relatively movable with respect to the scale and reads the INC track (or the ABS track). In this type of separate linear encoder, the scale and the detection head are separately provided, and both the scale and the detection head are assembled to chosen machinery or equipment such that they maintain a predetermined mutual positional relationship to each other. A signal strength from the scale is measured by an oscilloscope, and an inclination (yaw angle) of the detection head with respect to the scale (measurement axis direction) that is generated at the time of assembly is adjusted such that the amplitude is at a maximum value (Background Art described in Japanese Patent Application Laid-Open No. 2010-48786).