A semiconductor device has a first nitride semiconductor layer, a second nitride semiconductor layer formed on the first nitride semiconductor layer and having such a composition as to generate a 2-dimensional electron gas layer in the upper portion of the first nitride semiconductor layer, and an electrode having an ohmic property and formed selectively on the second nitride semiconductor layer. The second nitride semiconductor layer includes a contact area having at least one inclined portion with a bottom or wall surface thereof being inclined toward the upper surface of the first nitride semiconductor layer and defining a depressed cross-sectional configuration. The electrode is formed on the contact area.

The present invention relates to a semiconductor device composed of a group III-V nitride semiconductor and, more particularly, to a semiconductor device having an ohmic electrode formed on a group III-V nitride semiconductor layer and to a method for fabricating the same.
Studies have been made on the application of a group III-V nitride semiconductor, i.e., a mixed crystal compound semiconductor represented by the general formula AlxInyGa1-x-y (where x and y satisfy 0≦x≦1, 0≦y≦1, and 0≦x+y≦1) not only to an optical device using a wide band gap and a direct transition band structure, which physically characterize the mixed crystal compound semiconductor, but also to an electronic device using a high breakdown electric field and a high saturation electron velocity, which also characterize the mixed crystal compound semiconductor. In particular, a hetero-junction field effect transistor (hereinafter referred to as HFET) using a 2-dimensional electron gas (hereinafter referred to as 2DEG) appearing at the interface between an AlxGa1-xN layer (where 0<x≦1 is satisfied) and a GaN layer, each epitaxially grown on a semi-insulating substrate, as well as a hetero-junction bipolar transistor (hereinafter referred to as HBT) have been developed progressively as high-output RF devices.
In the HFET, an electron density is over 1013 cm−2 due to electrons supplied from a carrier supply layer made of, e.g., AlGaN and serving also as an n-type barrier layer and to charges resulting from a polarization effect (spontaneous polarization, i.e., piezo polarization). The electron density is higher than that in a HFET made of an AlGaAs-based compound semiconductor by about one order of magnitude.
In addition, a group III-V nitride semiconductor such as gallium nitride (GaN) features a high breakdown voltage characteristic due to its relatively large band gap energy of 3.4 eV. Because such electric characteristics as a high breakdown voltage and a high current density can be expected, studies have been made on the application of electronic devices using group III-V nitride semiconductors typically represented by the HFET and HBT as ultra-high-speed and large-output devices in smaller sizes.
Although the electronic devices using group III-V nitride semiconductors are thus promising as ultra-high-speed devices and large-output devices, various improvements and modification should be made to realize ultra-high-speed and large-output devices by using such nitride semiconductors.
As a first problem to be solved to realize an ultra-high-speed and large-output device using a group III-V nitride semiconductor, a reduction in contact resistance can be listed.
A description will be given herein below to a conventional GaN semiconductor device (HFET) using a group III-V nitride semiconductor with reference to FIG. 16 (see, e.g., Japanese Laid-Open Patent Publication No. 2003-59946).
As shown in FIG. 16, a GaN semiconductor device A has a first semiconductor layer 3 made of undoped GaN and formed on a substrate 1 with a buffer layer 2 interposed therebetween and a second semiconductor layer 4 made of undoped AlGaN which is larger in band gap energy than the first semiconductor layer 3 and formed on the first semiconductor layer 3. Consequently, a 2DEG layer 6 is formed in the region of the first semiconductor layer 3 located in the vicinity of the interface with the second semiconductor layer 4.
A Schottky gate electrode G is formed on the second semiconductor layer 4. The upper portions of the regions of the second semiconductor layer 4 located on both sides of the gate electrode G are partly removed such that two contact areas 4A are formed. A source electrode S and a drain electrode D, each of which is an ohmic electrode, are formed on the respective contact areas 4A. The exposed surface of the second semiconductor layer 4 is covered with an insulating film 7.
Thus, the conventional GaN semiconductor device A forms the contact areas 4A as regions to be formed with the ohmic electrodes by partly removing the upper portions of the second semiconductor layer 4 for generating the 2DEG layer 6 in the first semiconductor layer 3 and thereby reduces the distance between the 2DEG layer 6 and each of the ohmic electrodes S and D such that the contact resistance between the first semiconductor layer 3 and each of the ohmic electrodes S and D is reduced.
However, the conventional GaN semiconductor device mentioned above has the problems of a damage to the second semiconductor layer 4 caused by etching during the formation of the contact areas 4A and a reduction in the concentration of an electron gas in the 2DEG layer 6 caused by the etching damage to the second semiconductor layer 4.
Although the surface of the second semiconductor layer 4, especially the surface portions thereof located on both sides of the gate electrode G are covered with the insulating film 7, a leakage current (gate leakage) easily flows between the gate electrode G and the second semiconductor layer 4 under the influence of a surface level resulting from the exposure of the end faces. As a result, the electric characteristics (operating characteristics) of the device deteriorate even though the contact resistance is reduced.
There is also the problem that it is difficult to determine the end point of etching for forming the contact areas 4A having a depressed configuration.

Semiconductor device and method for fabricating the same

Matsushita Electric Industrial Co., Ltd.


A distributed database management system maintains logical collections of data. The collections may grow at varying rates, and may place storage and workload processing demands on the system that change over time. A value representative of the current maximum of capacity utilization for computing nodes in the system may be calculated. An estimate of the number of days for each computing node to reach the current maximum may be calculated, and compared to an average number of days. Computing nodes whose number of days is above the average may be selected to receive new logical collections of data.

A distributed database management system ("distributed database") may be provided by a hosting company to store and retrieve data maintained on behalf of the hosting provider's customers. Large quantities of data may be involved. Furthermore, each customer may add additional data to the system on an ongoing basis, following unpredictable patterns that may vary for each customer and change over time.
To handle large volumes of data, the distributed database may divide tables of data into logical collections of data sometimes known as partitions, which may each be hosted on different computing nodes in order to distribute the consumption of storage and workload capacity related to the table. Each partition may, in turn, contain various collections of logically related data. Partitions and the collections of data they contain may exhibit different characteristics regarding their usage patterns and growth characteristics. Some partitions and collections of data may grow rapidly, while others may grow slowly or remain more or less the same size.
To evenly distribute consumption of storage and workload capacity, a distributed database may use various techniques to determine which computing node, among the computing nodes that comprise the distributed database, should receive a new partition or collection of data. Random distribution or other similar techniques may be employed so that data may be evenly distributed. However, in some cases the resulting distribution of data may be skewed regarding the growth rates of data housed on each computing node. Some computing nodes may experience rapid growth that the node does not have the capacity to accommodate, while other computing nodes in the system experience little growth and remain under-utilized.


Method and apparatus in which a biomass is carried on a substrate that is fluidised. The fluidised substrate has a layer of distributor particles below it, through which the fluidizing medium passes prior to contact with the fluidised substrate and biomass associated therewith. The effect of the distributor layer is that the particles damp out excessive turbulence in the fluidizing medium, thus preventing undue turbulence of the medium within the fluidised layer. The particles may be recycled through the distributor layer to strip excess biofilm from the substrate particles prior to returning the substrate particles to the fluidised bed.

This invention relates to improvements in the design and operation of expanded or fluidised beds in which a fluid, particularly a liquid, is used to transmit the energy for bed expansion. An expanded or fluidised bed is one in which the particles are suspended in a fluid flow but do not substantially move with the bulk flow of that fluid. The classical chemical engineering definition of an expanded bed is one that is increased in volume up to 50% or 100% over that of the bed when static, i.e., with no fluid flow; whilst a fluidised bed is defined as having a volume more than 50% or 100% greater than that of the static bed with no fluid flow. In particular, the present invention relates to biological processes such as water and wastewater treatment, fermentation, and bio-catalysis. For such processes, areas in need of improvement include distribution of the liquid flow; energy costs for pumping and aeration; control of biomass overgrowth; and biomass support materials
Recent publications in the scientific literature have highlighted aspects of fluidised bed design and operation, which are in need of improvement. For example, P. M. Sutton and P. N. Mishra ("Activated carbon based biological fluidised beds for contaminated water and wastewater treatment: a state of the art review", Water Science and Technology Vol. 29 10-11: 309-317, 1994) point out that "The mechanical components and sub-systems critical to the design of BFB (biological fluidised bed) commercial system embodiments are the following" and went on to cite the distributor, oxygen transfer, and control of biofilm growth. Their paper was based on a review of "Over 80 commercial, media-based BFB reactors (that) have been installed in North America and Europe."
In a more recent review, C. Nicolella, M. C. M. van Loosdrecht and J. J. Heijnen ("Wastewater treatment with particulate biofilm reactors", Journal of Biotechnology 80: 1-33, 2000) identified four key disadvantages of fluidised bed operation:
1. Biofilm formation on carriers, which poses problems leading to long start-up times.
2. Difficulty in control of biofilm thickness.
3. Overgrowth of biofilm leading to elutriation of particles.
4. High cost of liquid distributors for fluidised systems for large-scale reactors and associated problems with respect to clogging and uniform fluidization.
Since the introduction of liquid fluidised bed technology, a number of patents have been granted for devices to ensure the uniform distribution of liquid flow at the base of the bed. These include downward flow through expansion nozzles (e.g., U.S. Pat. No. 4,202,774, U.S. Pat. No. 4,464,262, U.S. Pat. No. 4,618,418, U.S. Pat. No. 5,584,996); nozzles with a perforated grid or plate above (U.S. Pat. No. 4,702,891, U.S. Pat. No. 4,933,149); perforated distributor plates, similar to those used in conventional gas-fluidised systems (U.S. Pat. No. 4,322,296) or with a static bed of coarse sand and fine grades of sand above (U.S. Pat. No. 5,965,016); or simply a static bed of granular material (U.S. Pat. No. 5,895,576), sand (GB780406) or both (GB2149683).
If the fluid flow at the base of the bed is turbulent, this results in increased impacts between fluidised particles producing abrasion, or in the case of particles carrying a reactant layer, premature stripping of the reactant layer from the fluidised carrier particles.
GB780406 discloses a particulate distributor comprising a static bed of sand lying on a perforated screen with flow rates of the order of 1 gallon per square foot per minute (49 L per m2 per mm) or an upward velocity of about 0.08 cm per cm per sec. This low rate of flow through the distributor is insufficient to cause movement of its particles, and the teaching here is that the granular material is being used in effect as a "3-dimensional" perforated plate. In an attempt to improve the fluid flow characteristic in a fluidised bed, Bernard Suchowski, Joseph E. Gargas, Robert H. Hyde and Joseph Pluchino (U.S. Pat. No. 5,965,016) proposed the use of larger and heavier particles of sand collected just above a perforated distributor plate, where they help distribute the flow more evenly.
In spite of this, the presence of the perforated plate itself poses physical constraints to fluid flow.


A digital player interface device with exchangeable adapter is provided to comprise an adapter providing with a through hole for load-on/off of a digital player and a first and a second engaging parts on its both end; an adapter-fixing element having a guiding rib and a concavity with a fixing spring; and a chassis having a guiding groove, a restriction groove and a adapter snapper. When the adapter is sliding on the chassis, the adapter pushes the adapter-fixing element moving along the guiding groove, and the fixing spring is released from the restriction groove to engage the first engaging part of the adapter. When the adapter is removed from the chassis, the adapter-fixing element moves back to a home position.

1. Field of the Invention
The present invention relates generally to a digital player interface device with exchangeable adapter, and more particularly to a digital player interface device with exchangeable adapter suitable for various size digital player.
2. Description of Related Art
With the development of growing mature digital video technology, a variety of digital video formats have been developed, such as: MP3 (ISO-MPEG Audio Player-3), MP4 (MPEG-4), RMVB (Real Media Variable Bitrate), which features compactness and exhibits excellent images/voice quality; so digital players are specifically developed along with the widespread permanent flash memory.
Unlike a traditional digital player, the aforementioned digital player mainly uses the flash memory or micro HD as the storage medium other than cassette or CD; thus digital player has been designed and developed with thin-profile and innovative design, among the digital player, iPod player developed by APPLE, is a representative and most popular product in this field.
Each year a new iPod-generation from APPLE comes to the market and these devices get more and more popular. These digital players with music playing and recording function allow people to watch TV and video channels by connecting to computer, amplifier, television and car audio-infotainment-system through a connection interface.
Despite of the functional modification of the aforementioned digital players, there is a big room for improving the interfacing between the digital player and computer, e.g. the digital player is generally interfaced with the computer via an exposed socket, namely, the digital player lacks of a safe storage space, leading possibly to the interference by surroundings or even damage of the thin-profile player; in addition, the terminal adaptor for the player is susceptible to dust against the interfacing performance and appearance.
Thus, to provide a safe and dust-free storage space, it would be advanced if the art could develop an improved structure which is suitable for various kinds of digital player having different size and is capable of data exchanging with the computer and also electric charging.
Accordingly, the present inventor has investigated on the digital player and interface on electronic devices such as computers and thus completed the present invention.

Digital player interface device with exchangeable adapter

Philips & Lite-On Digital Solutions Corporation


An organic EL device including an anode, a cathode, and an organic electroluminescent element between the anode and the cathode; the organic electroluminescent element includes an organic material or a mixture thereof of 9,10-bis(3'5'-diaryl)phenyl anthracene derivatives.

Organic EL devices are known to be highly efficient and are capable of producing a wide range of colors. Useful applications such as flat-panel displays have been contemplated. The work on the improvement in organic EL devices such as color, stability, efficiency and fabrication methods have been disclosed in U.S. Pat. Nos: 4,356,429; 4,539,507; 4,720,432; 4,885,211; 5,151,629; 5,150,006; 5,141,671; 5,073,446; 5,061,569; 5,059,862; 5,059,861; 5,047,687; 4,950,950; 4,769,292, 5,104,740; 5,227,252; 5,256,945; 5,069,975; 5,122,711; 5,366,811; 5,126,214; 5,142,343; 5,389,444; 5,458,977; 5,536,949; and 5,683,823.
The organic EL device includes an organic EL element consisting of extremely thin layers (<1.0 micrometer in combined thickness) between the anode and the cathode. Herein, the organic EL element is defined as the organic composition between the anode and cathode electrodes. In a basic two-layer EL device structure, one organic layer of the EL element adjacent to the anode is specifically chosen to inject and transport holes, therefore, it is referred to as the hole transport layer, and the other organic layer is specifically chosen to inject and transport electrons, referred to as the electron transport layer. The interface between the two layers provides an efficient site for the recombination of the injected hole-electron pair and the resultant electroluminescence. There is also a three layer organic EL device which contains a light-emitting layer between the hole transport layer and electron transport layer that has been disclosed by Tang et al [J. Applied Physics, Vol. 65, Pages 3610-3616, 1989]. The light-emitting layer commonly consists of a host material doped with a guest material. The host materials in light-emitting layer can be electron transport materials, such as 8-hydroxyquinoline aluminum complex [U.S. Pat. No. 4,769,292], the hole transport materials, such as aryl amines [Y. Hamada, T. Sano, K. Shibata and K. Kuroki, Jpn. J. Appl. Phys. 34, 824,1995], or the charge injection auxiliary materials, such as stilbene derivatives [C. Hosokawa et al., Appl. Phys. Lett., 67(25) 3853, 1995]. The doped guest materials, also known as the dopant, is usually chosen from highly fluorescent dyes. In the three layer organic EL device, the light-emitting layer provides an efficient site for the recombination of the injected hole-electron pair followed by the energy transfer to the guest material and produces the highly efficient electroluminescence.
In general, the host material in the light emitting layer should be as fluorescent as possible and the fluorescence wavelength should be in the blue or near the UV region. The latter attribute is important for down-shifting of the EL emission wavelength in a host-guest emitter layer. Among the blue fluorescent materials, 9,10-(diphenyl)anthracene has a near unity fluorescence quantum efficiency in solution. This compound is also highly fluorescent in the solid state. However, as a host material for the EL emitter layer, the film-forming property of 9,10-(diphenyl)anthracene is very poor, resulting in highly polycrystalline film which tends to produce electrical shorts in the EL device. Several improvements in 9,10-(diphenyl)anthracene have been disclosed. EP 0681019 disclosed the use of a dimeric structure of 9,10-(diphenyl)anthracene in improving the film-forming property and the solid fluorescence efficiency. EP 0786926 disclosed that the amino derivatives of 9,10-(diphenyl)anthracene are useful as emitters in organic EL device.

Organic electroluminescent elements for stable blue electroluminescent devices


An article such as a hollow gas turbine blade has an internal cavity therein with an inlet and outlet. The outlet has an outlet minimum transverse dimension of from about 0.009 inch to about 0.012 inch. An aluminiding source powder has a minimum particle size of greater than about 0.0015 inch and not greater than about 0.005 inch. The aluminiding source powder is a mixture of from about 5 to about 15 percent by weight of a metallic aluminum-containing powder and from about 85 to about 95 percent by weight of a ceramic powder. The aluminiding source powder is flowed into the internal cavity through the inlet, and the article is heated with the aluminiding source powder in the internal cavity to a temperature of from about 1750° F. to about 2000° F., and for a time of from about 2 hours to about 12 hours, to deposit an aluminum-containing coating on the internal surface of the internal cavity. The aluminiding source powder is thereafter removed from the internal cavity through the inlet.

In an aircraft gas turbine (jet) engine, air is drawn into the front of the engine, compressed by a shaft-mounted compressor, and mixed with fuel. The mixture is burned, and the hot combustion gases are passed through a turbine mounted on the same shaft. The flow of combustion gas turns the turbine by impingement against an airfoil section of the turbine blades and vanes, which turns the shaft and provides power to the compressor. The hot exhaust gases flow from the back of the engine, driving it and the aircraft forward.
The hotter the combustion and exhaust gases, the more efficient is the operation of the jet engine. There is thus an incentive to raise the combustion and exhaust gas temperatures. The maximum temperature of the combustion gases is normally limited by the materials used to fabricate the hot-section components of the engine. These components include the turbine vanes and turbine blades of the gas turbine, upon which the hot combustion gases directly impinge, and other hot-section components as well. In current engines, the turbine vanes and blades are made of nickel-based superalloys, and can operate at temperatures of up to about 2150° F. These components are also subject to damage by oxidation and corrosive agents, as well as impact damage and erosion by particles entrained in the combustion gas stream.
Many approaches have been used to increase the operating temperature limits and service lives of the hot-section components such as the turbine blades and vanes to their current levels, while achieving acceptable oxidation, corrosion, erosion, and impact resistance. The composition and processing of the base materials themselves have been improved. Portions of the external surfaces of the turbine blades and vanes are coated with a protective aluminide environmental coating and, in some cases, an insulating thermal barrier coating is applied overlying the aluminide coating.
Physical cooling techniques are also used. In one practice, the component is provided with an internal cooling cavity. Compressor bleed air flows into the internal cooling cavity through an inlet in the root of the component, and out of the internal cooling cavity through small-diameter outlets, such as found at the leading edge, trailing edge, and faces of the turbine blade. The air flow carries heat away from the cooled component and also provides film cooling. This physical cooling technique has allowed the hot-section components to run even hotter than possible for uncooled components.
As the operating temperatures have been pushed even further upwardly, it has been found that the internal surfaces of the internal cooling cavities experience oxidation and other degradation during service, particularly near the tip of the turbine blade. Therefore, more recently internal coatings have been applied to protect the internal surfaces of the hollow components.
However, the application of coatings to the internal surfaces poses some problems not found for external coatings, particularly because of the presence of the small-diameter outlets. Existing external coating techniques, when applied to internal coating, and candidate internal coating techniques are not sufficient to achieve the necessary internal coatings.
There is a need for an improved approach to coating internal surfaces of hollow articles having small-diameter outlets. The present invention fulfills this need, and further provides related advantages.

Dimensionally controlled pack aluminiding of internal surfaces of a hollow article


A battery powered, low voltage faucet flow timer, water usage calculator, and energy consumption awareness meter is simple to install and calibrate and may enable a user to understand the water usage associated with showering, bathing or other open faucet water use activity. The device may provide a simple method for calculating the flow characteristics for a shower, bath or other faucet and entering this flow rate into the timing device so that the timer provides an accurate calculation of water usage indicating both the time spent with the water running and approximate total water usage.

1. Field
The present invention relates to an energy consumption awareness and flow meter.
2. Description of the Related Art
As the world human population grows and our global civilization becomes ever more industrialized, the fresh water supply of planet Earth is coming under increasing pressures. In some areas, such as California and the South West of the United States, the needs of the burgeoning population require importing water from great distances to meet the demand. As these pressures on the water supply continue to grow, the cost of water is destined to increase dramatically. Many people already feel the pinch. It is generally understood that basic conservation measures constitute the best first step to improving the pressures on the water supply and to alleviating the increasing personal costs associated with water usage. As with many conservation efforts, education and information are the foundation to a successful implementation. The invention provides a device and methods of improving awareness, such as within a household or a business, of water consumed through, for instance, bathing and showering, and encourages conservation by providing information related to the duration of water use and the total water consumed.

Faucet flow timing system that monitors volume of water usage


The present invention allows a back-up site used for disaster recovery to be constructed in a shorter period of time.

1. Field of the Invention
The present invention relates to a method for operating a storage system comprising a main site and a back-up site.
2. Description of the Related Art
A storage system provides large-capacity and high-performance storage services to a host computer (business server, and the like). In a storage system, for example, a storage region is constituted on the basis of a RAID (Redundant Array of Independent Inexpensive Disks), formed by providing a plurality of disk drives in an array configuration. Logical volumes (LU: Logical Units), which are logical storage regions, are formed in the physical storage regions provided by the respective disk drives. A host computer is able to read and write data from and to these logical volumes.
The storage system stores and manages a large volume of data groups of various types which are used in a variety of organizations, such as businesses, autonomous bodies, universities, and the like, for example. In many cases, these data groups are absolutely indispensable to the activities of the organization. Therefore, various countermeasures are adopted in a multi-layered fashion in the storage system, in order to prevent the loss of important data groups, or situations where data groups become unusable.
For example, redundancy is created in the physical configuration and logical configuration of the storage system, by adopting an alternative path structure or a RAID structure, or the like, in order to prepare for the occurrence of faults, or the like. Furthermore, in a storage system, it is possible to back up the storage contents of the logical volumes, to a back-up device, such as a tape device, or the like, at regular or irregular intervals.
Furthermore, in a storage system, in order to prepare against large-scale disasters, such as earthquakes, or the like, for example, a back-up site can be situated in a location that is distant from the main site, in what is known as a "disaster recovery" system. Disk array devices for backing up data are located in this back-up site, and the storage contents thereof are synchronized with those of the disk array devices in the main site.
Remote copy technology is used in order to synchronize the storage contents in the main site and the back-up site. In a remote copy system, the respective disk array devices are mutually connected by means of a dedicated communications circuit or a public circuit, and the data is copied directly between the respective disk array devices, without passing via a host computer (see Japanese Patent Laid-open No. 2002-7304).
Furthermore, for example, a method is also known whereby the storage contents of the disk array device in the main site are backed up to magnetic tape, which is taken to the back-up site, and then restored onto the disk array device of the back-up site.
Moreover, technology is also known whereby disk drives are replaced in a frame, or moved to a different frame (Japanese Patent Laid-open No. 2001-337792).
When the storage contents of the main site are to be copied to a back-up site, firstly, an initial copy is made (establish copy), and the storage contents of the main site at a particular point in time are copied exactly to the back-up site. Thereupon, the data updated in the main site is transferred to the back-up site, as differential data, and is copied to a storage region of the back-up site.
In a method wherein the initial copy is carried out via a communications circuit, although the situation may vary depending on the bandwidth and speed of the communications circuit, and the volume of the data to be copied, and the like, in general, a long time is required in order to make the initial copy. Therefore, it takes time for the back-up site to start up. Furthermore, if the communications circuit is occupied for the purposes of making the initial copy, then this may affect other types of data communications using the same communications circuit.
In a method whereby the data at the main site is backed up onto magnetic tape and then taken to the back-up site, no communications circuit is required. However, in general, the data write speed and data read out speed of a tape device is slower than that of other storage devices, and hence a long time is required in order to start up the back-up site. Since magnetic tape, which has a slow access speed, is used for both writing the data from the main site and reading out data into the back-up site, then it takes time to construct the back-up site. Furthermore, the magnetic tape device used for back-up is a control device that is completely independent from the disk array device. Consequently, if data back up based on the use of magnetic tape is to be adopted, then a magnetic tape device must be purchased.
In the reference patents described above, a method is disclosed wherein disk drives are moved to different frames. However, this reference patent simply discloses a method for moving an original disk drive to another frame, and it does not consider the construction of a back-up site for the purpose of disaster recovery.

Method for operating storage system including a main site and a backup

Abstract: In a disk array device 1 at a main site, a copy 4 of a RAID group 3 is generated. In-frame mirroring is used to generate this copy. The RAID group 4 is removed from the disk array device 1 by an operator and transported to a back-up site. The operator then installs each of the disks of the RAID group 4, respectively, in the disk array device 2, in such a manner that they adopt the same positions as in the RAID group 3. The configuration information 5 used in order to manage the RAID group 3 is downloaded to the disk array device 2 in the back-up site, by means of a portable storage medium 8, or via a communications network 7. Thereupon, the differential data between the disk array devices 1, 2 is reflected in the disk array device 2, whereupon construction of the back-up site is complete.


A SAW device includes two surface-acoustic-wave filter elements arranged so as to have a balanced-to-unbalanced conversion function. The surface-acoustic-wave filter elements include two first reflectors and two second reflectors. In each surface-acoustic-wave filter element, three IDTs are arranged on a piezoelectric substrate in a direction in which surface acoustic waves are transmitted so as to be positioned between one first reflector and one second reflector. The first reflectors differ in structure from the second reflectors.

1. Field of the Invention
The present invention relates to a surface acoustic wave (SAW) device having a balanced-to-unbalanced conversion function, and a communication apparatus including such a SAW device.
2. Description of the Related Art
There has been remarkable technological progress in the reduction in the size and weight of communication apparatuses in recent years. In order to achieve such reduction, not only are components reduced in number and size, but also combined components formed by combining functions have been developed.
With these circumstances as background, a SAW device for use in a radio frequency stage of a cellular phone having a balanced-to-unbalanced conversion function, or a so-called "balun" function, has been actively studied in recent years. Mainly, global systems for mobile communications (GSM) have come into use. Some patent applications concerning SAW devices provided with balanced-to-unbalanced conversion functions as described above have been filed.
In addition, recently developed cellular phone systems have close transmitting and receiving frequencies which have increased. With such increase, an attenuation in a receiving frequency band must be increased in a transmitting filter, and an attenuation in a transmitting frequency band must be increased in a receiving filter. Accordingly, in a SAW device, the need to increase an attenuation in the vicinity of a passband has become strong.
In a communication apparatus, it is common to use a characteristic impedance of 50 Ω in a portion from an antenna to a filter for an unbalanced signal. In many cases, in an amplifier or other component which is used after the stage of the filter, an impedance of 150 Ω to 200 Ω is used for a balanced signal.
Regarding a SAW filter device (SAW device) which also has a function of converting a 50-Ω unbalanced signal into a balanced signal having 150 Ω to 200 Ω, for example, a device in which four SAW filter elements are used to realize an unbalanced input and a balanced output is known (see, for example, Japanese Unexamined Patent Application Publication No. 10-117123). The configuration of the SAW filter device disclosed in this publication is shown in FIG. 24.
In the configuration, which is known, a spurious component in the vicinity of the passband outside of the passband is caused by excitation of surface acoustic waves. In a range in which the spurious component is generated, the phase characteristics of balanced terminals 506 and 507 are inverted as in the passband. Accordingly, a signal canceling effect in a differential state is not obtained, thus causing a problem in that the attenuation in the vicinity of the passband outside the passband is insufficient.
SAW device configurations of the related art are described below with reference to FIGS. 19 to 24.
FIG. 19 shows a SAW device 100 in which, in a configuration having the impedances of balanced signal terminals 114 and 115 which differ by approximately four times the impedance of an unbalanced signal terminal 113, an attenuation in the lower range of a passband can be increased.
As shown in FIG. 19, the SAW device 100 includes two longitudinally-coupled-resonator SAW filters (SAW filter elements) 101 and 102 on a piezoelectric substrate (not shown). The longitudinally-coupled-resonator SAW filter 101 includes three interdigital transducers (IDTs) 103, 104, and 105, and reflectors 106 and 107 on the sides of the IDTs 103 and 105. Similarly, the longitudinally-coupled-resonator SAW filter 102 includes three IDTs 108, 109, and 110, and reflectors 111 and 112 on the sides of the IDTs 108 and 110. The IDTs 103 to 105, and the IDTs 108 to 110 are arranged in a row along a propagation direction of surface acoustic waves. In the SAW device 100, the IDTs 108 and 111 of the longitudinally-coupled-resonator SAW filter 102 are inverted along an interdigital length compared with the IDTs 103 and 105 of the longitudinally-coupled-resonator SAW filter 101. In this arrangement, in the longitudinally-coupled-resonator SAW filter 102, the phase of an output signal to an input signal differs by approximately 180 degrees compared with the longitudinally-coupled-resonator SAW filter 101.
The IDTs 104 and 109 are connected to a signal terminal 113. The IDTs 103 and 105 are connected to a signal terminal 114. The IDTs 108 and 110 are connected to a signal terminal 115. In the SAW device 100, the signal terminal 113 is an unbalanced signal terminal, and the signal terminals 114 and 115 are balanced signal terminals.
Each IDT includes two electrode-finger units each including a bar base-end portion (bus bar) and a plurality of mutually-parallel bar electrode fingers which extend in a perpendicular direction from one side of the base-end portion. Both electrode-finger units are arranged so that the side portions of the electrode fingers of one unit face the side portions of the electrode fingers of the other unit. Also, each reflector is used to reflect transmitted surface acoustic waves. The reflector includes a pair of bar base-end portions (bus bars), and a plurality of mutually-parallel bar electrode fingers which extend in a perpendicular direction from one side of one base-end portion and which electrically connect the base-end portions.
As described above, the SAW device 100 which has a balanced-to-unbalanced conversion function and in which the impedance of balanced signal terminals differs by approximately four times that of an unbalanced signal terminal is realized.
A feature of the SAW device 100 is that the number of electrode fingers in each of the reflectors 111 and 112 is less than that in each of the reflectors 106 and 107. In other words, the longitudinally-coupled-resonator SAW filters 101 and 102 have different numbers of electrode fingers.
As a comparison with the SAW device 100, a SAW device 120 (comparative example 1) which includes two longitudinally-coupled-resonator SAW filters 101′ and 102 on a piezoelectric substrate (not shown) is shown in FIG. 20. The SAW device 120 has a configuration in which, in the SAW device 100, instead of the reflectors 106 and 107, reflectors 106′ and 107′ which are identical in number of electrode fingers to the reflectors 111 and 112 are provided. In other words, in the SAW device 120, the longitudinally-coupled-resonator SAW filters 101′ and 102 have the same number of electrode fingers of reflector. The other points in configuration are identical to those in the SAW device 100.
FIG. 21 shows frequency-to-insertion-loss characteristics of the SAW device 100 shown in FIG. 19 and the SAW device 120 shown in FIG. 20. From FIG. 21, it is seen that the configuration of the SAW device 100 has an improvement of approximately 5 dB around 1780 MHz in the passband compared with the SAW device 120. This is an effect of the difference in reflection characteristics of reflector between the longitudinally-coupled-resonator SAW filters 101 and 102.
The configuration of the SAW device 100 in FIG. 19 has a problem in that an attenuation in identical components (common mode) in the lower range of the passband deteriorates. FIG. 22 shows frequency-to-common-mode-attenuation characteristics of the SAW device 100 and SAW device 120. A common mode attenuation around 1640 MHz to 1780 MHz is 30 dB in the SAW device 120, while it deteriorates to 23 dB in the SAW device 100.
This is caused by deterioration in amplitude balance and phase balance in the lower range of the passband due to the difference in reflection characteristics of reflector between the longitudinally-coupled-resonator SAW filters 101 and 102. For recent SAW devices having a balanced-to-unbalanced conversion function, it is required that an attenuation be increased not only in the passband, but also in the common mode outside the passband. The configuration of the SAW device 100 has a technical problem in that the request cannot be satisfied.

Surface acoustic wave device and communication apparatus including the same


A comprehensive time determining system includes a list of geographical locations located on a periphery thereof. The base section further includes a plurality of time zones associated with the geographical locations. The time zones are presented on a time strip on the base section. The list of geographical locations on the base section includes locations using standard time only. A first movable section includes a northern hemisphere portion and a southern hemisphere portion. The northern hemisphere portion and the southern hemisphere portion are each independently movable relative to the base section. The northern hemisphere portion includes a list of northern hemisphere geographical locations. The southern hemisphere portion includes a list of southern hemisphere geographical locations. The lists on the first movable sections contains locations using dual time, the northern hemisphere portion and the southern hemisphere portion being movable to select a desired position depending on the season. The first movable section is so arranged and constructed to allow the user to be able to view the time strip located on the base section. A second movable section includes a rotatable dial, the dial being rotatable relative to the base section and to the first movable section. The dial includes evenly spaced markers positioned about a periphery thereof representing the hours in a day. During use, an operator selects a location on either the base section or the first movable section and adjusts the first movable section depending on the season, and sets the dial so that a reference time on the dial element is set to a reference time on the time strip. The user can then use the evenly spaced markers on the dial to determine time at any selected geographical location on the base section or first movable section.

1. Field of the Invention
The present invention relates generally to portable time conversion devices and more particularly to devices that provide the capability of calculating local time, both standard and adjusted, at various places in the world.
2. Description of the Related Art
Although many time calculating or displaying inventions have been introduced over the years, there are still some problems that need to be solved in order to satisfy the needs of users such as frequent travelers, businessmen, international disaster relief workers, and many others. Various inventions have their own strengths, yet it seems that some important problems have not been satisfactorily dealt with.
The following problems have been considered, as the present invention has been developed.
1. Some inventions do not have much space for a list of geographical locations.
2. There are countries such as the U.S.A. that use adjusted (daylight saving) time during part of a year. Unless this problem is properly dealt with, time calculation between these places and other countries that do not change time would be inaccurate or difficult, if not impossible. Moreover, some states or cities within these countries such as Arizona do not adjust time at all while other states adjust time. This can be confusing or may cause serious problems.
3. For places that are not mentioned or addressed on a time calculating device, one has to rely on other methods. Otherwise, one simply cannot calculate the time.
4. When there is ambiguity, how does a user make decisions? For example, when a location is situated between two different 15 degree longitudes, how does the user know the correct choice? When a big country such as the People's Republic of China stretches East to West covering many "time zones" or multiples of 15 degree longitude, how does the user know which time they use or how many time zones they have in the country? Interestingly, China, as large as the contiguous 48 states of the United States, has only one time, which is centered on the capital city, Beijing.
5. For many people living in a country where they have only one time zone or use only one time, it is mind boggling that a country has more than one time. Many Asians seem to be puzzled when they hear that the U.S. has multiple time zones, while many Americans seem to be surprised when they hear that China, a big country as large as the U.S. is using only one time and that they do not have daylight saving time, that is, they use only one time throughout a year.
6. Use of a one half (½) hour time zone also can cause confusion. Not many people living outside of India may know that this country with more than one billion population is five and half (5½) hours ahead of the Greenwich Mean Time (GMT). This one half (½) hour time may limit the use of many time calculating devices. It is noted that Greenwich Mean Time (GMT) is the same as UTC (Coordinated Universal Time) or UT (Universal Time).
7. What about a general question such as "What time is it now in Australia?" Not many people in Asia or the U.S. may know that Australia has three time zones, not to mention that one of these three time zones uses one half hour time. Interestingly, they have three time zones, GMT+8, +9.5, and +10.
8. The use of 15 degree longitude for one hour time zone does not necessarily match with each time zone. For example, in South America, some parts of western Brazil are further East than most of Argentina but Argentina time is one hour ahead of these parts in Brazil.
9. It is necessary to show the bird's eye view of time zones of the world. For example, if one wants to see how many time zones are in the U.S., Australia, India, or China, it is not easy to learn quickly from an ordinary dial type or other slide rule type world time calculators. Also, determining time difference between a particular location and the Greenwich Mean Time should not be too difficult or cumbersome.
10. In order to deal with detailed information, it is necessary to have sufficient space. However, if it takes too much space, it is not easy to carry this calculator or displayer. One needs a system that can be effective and informative, yet, it has to be small enough to be carried around relatively easily.
11. In order to deal with people living in various countries and cultures, more than one language or script should be considered.
Thus, in order to deal with all the aforementioned issues, it is necessary to show the bird's eye view of the world as well as the detail list of locations using a particular time. Furthermore, for those who are not familiar with world time, it would be good to provide some types of explanation of important concepts or background information (such as the definition and history of daylight saving time). Index of many countries and cities of the world is also needed for quick references.
U.S. Pat. No. 7,050,357, issued to Garcia, entitled "Global Time Indicator" discloses a global time indicating calculator that has a clock member with a rotating dial for calculating global standard time and advanced time in various international time zones. Indicia printed on the face of the dial and corresponding boxes on oppositely opposed faces of the calculator can be easily referenced to determine time of day at selected locations throughout the world. The faces have recesses therein to interchangeably accommodate the clock member whereby the calculator can be modified to calculate the time of day during either standard time or advanced time periods. But it may be difficult for non-Americans who do not know the definition of some concepts and abbreviations used on the device. For example, someone in Asia who is not familiar with American time system may wonder "What are the PT, MT, CT, ET?" or "When do they use the advanced time?" This invention also seems to have problem with space. If a location is not listed on the device, how can a user find the correct time? Since names are not arranged alphabetically and no index seems to be provided, one has to struggle to find the desired location. If one wants to know the time of a country instead of a city, it is not easy unless he or she is quite familiar with world geography.
U.S. Pat. No. 6,330,970, issued to Whalen, entitled, "Global Time Calculator" discloses a global time calculator that includes an insert and a sleeve. The insert is marked on both its sides (or on a single page slide insert on one side) with vertical columns of incremental time designations, and may or may not contain a stop mechanism. The insert is slidable and connected with the sleeve so as to be shiftable in a vertical direction. Both sides of the sleeve (or in some embodiments a single side of the sleeve) have areas for obscuring vertically aligned time designations that are in excess of unobscured time designations. But this device does not handle daylight saving time and time zones that use one half hour time.
U.S. Pat. No. 5,303,956, issued to Zoland, entitled, "Time Zone Conversion Chart for Card, Luggage Tag or Key Chain" discloses a travel document folder, card case or luggage tag that features a time zone conversion chart. But this device does not provide many locations due to limited space and size of the dial.
U.S. Pat. No. 5,007,033, issued to Kubota et al., entitled, "World Timepiece" discloses a world timepiece for normally displaying the time of a home city and for selectively displaying the time of another city situated in another time zone. The world timepiece includes a plurality of selector switches corresponding to main cities located in different time-lag zones into which the world is divided. A display unit normally displays the time of the user's home city and, upon actuation of one of the selector switches, the display unit displays the time of the selected city designated by the actuated selector switch. A city of an arbitrary time-lag zone can be stored in an assigned city storage circuit, and the time of the assigned city can be displayed by the display unit by actuating an optional switch. This invention does not list many cities that belong to the same time zone. A foreigner who does not have extensive knowledge of the regional geography such as various time zones of the U.S. may have difficulty using it. Another problem is that use of daylight saving time is not clearly addressed. For example, most of the U.S. uses daylight saving time part of a year, but there are exceptions for some areas and cities.
U.S. Pat. No. 4,681,460, issued to Nishimura, entitled, "World Time Watch" discloses a world time watch that has a liquid crystal display device including a time zone display and a time display. The time zone display is provided to display the time difference between a selected place and the Greenwich Mean Time, and the time display is provided to display the time of the place corresponding to the time difference displayed in the time zone display. A printed place name list is provided around the liquid crystal display device. The place name list includes a plurality of numbers each of which represents the corresponding time difference of a particular place. The Nishimura device does not deal with half hour time zone and adjusted time (daylight saving time). Also, space allocated for each time zone is not enough.
U.S. Pat. No. 4,032,754, issued to Ageton, entitled, "Global Time System" discloses a global time system having a first disc divided into twenty-four equal sections, each section being formed by lines extending radially from the center of the first disc. Each line forming the sections represents a line of longitude. Circles are concentrically disposed about the center of the disc and extend outward to the edge of the disc. The circles, representing lines of latitude, cross over each of the twenty-four lines of longitude to form geographic spaces between the lines of longitude and latitude. A time disc is rotatably mounted to the center of the first disc and has twenty-four lines equally spaced from each other on the outside edge. Reference symbols are positioned on the first disc and adjacent to the outside edge of the time disc, with the reference symbol in each of the twenty-four sections. Identification symbols representing a specific geographic location are disposed within the respective geographic space having the proper longitude and latitude of the location. However, just knowing reference point, longitude and latitude, cannot provide local time accurately. For example, China stretches out multiple time zones but it uses only one time.


Vibration damper comprising a cylinder in which a piston rod is guided with freedom of axial movement, where the piston rod cooperates with a piston arrangement comprising a first, stationary piston and at least one additional piston, which is supported on the piston rod with freedom of axial movement against the elastic force of at least one restoring spring, where the cylinder is divided by the stationary piston and by the minimum of one axially movable piston into a working space on the side of the piston facing the piston rod, a working space on the side of the piston facing away from the piston rod, and a working space between the two pistons, where valve-equipped through-openings control a connection between the working spaces, and where the axial movement of the minimum of one axially movable piston is limited by a hydraulic pressure stop.

1. Field of the Invention
The invention pertains to a vibration damper of the type having a piston rod guided with freedom of axial movement in a cylinder; a first piston fixed to the piston rod so that the first piston is stationary with respect to the piston rod, the first piston bounding a first working space facing away from the piston rod; and a second piston mounted on the piston rod with freedom to move axially with respect to the first piston against the force of at least one restoring spring, the second piston bounding a second working space facing the piston rod and an intermediate working space between the pistons; and at least two openings in each piston connecting the working spaces, the openings being equipped with non-return valves.
2. Description of the Related Art
A vibration damper with a cylinder in which a piston rod is guided with freedom of axial movement, where a first piston is mounted in a stationary manner on the piston rod and a second piston is mounted with freedom to move axially on the piston rod against an elastic force, is known from the U.S. Pat. No. 6,651,787, which represents the state of the art. The two pistons divide the cylinder into a working space on the side of the second piston facing the piston rod, a working space on the side of the first piston facing away from the piston rod, and a working space between the two pistons. Valve-equipped through-openings control a connection between the working spaces. The second piston has at least one restoring spring on each side and is supported so that it can move in either of the two axial directions against the force of the restoring springs.
This vibration damper design offers very comfortable driving behavior in many types of vehicles. There are applications, however, in which the forces generated by the restoring springs are too weak, as a result of which each of the restoring springs is formed by two springs arranged one inside the other to form a set. These sets of springs, however, are difficult to install and occupy a relatively large amount of radial space. Springs with a progressive spring characteristic are very expensive.


It is an object of the present invention to provide a method for manufacturing a high-quality foam that can be produced stably on an industrial scale and that affords excellent thermal insulation as a foam with thin cell membranes, which method ensures uniform molten mixture fluidity, which is an essential condition for achieving consistent foam quality, in the manufacture of a foam by mixing starch as one molten polymer compound with another polymer compound having a different melt viscosity, and to provide a foam manufactured by this method. Water is added to and mixed with a plant-derived fibrous material and starch to manufacture a foam of a plastic resin containing as compositional components starch and a plant-derived fibrous material such as pulverized paper, pulverized wood, or the like. A foam is manufactured by a method comprising a step of producing pellets in which starch molecular spheres are agglomerated to each other or to the plant-derived fibrous material without the starch undergoing agglutination, and the step of foaming the pellets by mixing them with a plastic resin, and included in between these two steps is a step of drying the pellets at a temperature not higher than the starch agglutination temperature.

There have been countless attempts at manufacturing a foam by mixing starch with another plant-derived material or with a plastic resin that would pose no danger of emitting dioxins if incinerated after use, for example, and at utilizing such foams as thermal insulation materials or as cushioning materials or other such shipping and packaging materials, and a number of methods for manufacturing foams have been disclosed. Nevertheless, based on an examination of this disclosed information, it appears that no known technique has been established relating to the problem the present invention is intended to solve. To clarify the problem the present invention is intended to solve, general concepts, beliefs, related examples, and so forth were examined in the technological field to which the present invention is related.
It is commonly held that when steam or the like is used as a foaming gas, the material is discharged under pressure from an extrusion molding machine, and reduced-pressure foaming is performed, for instance, a polymer raw material that becomes fluid when the temperature is raised will flow as shown in FIG. 6A, with symmetrical flow lines around the center line in the drawing, when the pressure is relatively low, and as the pressure is gradually raised, slip is observed between the material and the walls. At even higher pressures the flow lines begin to be disarrayed, the material is extruded in a spiral shape, and this results in a lack of uniformity in the material. What happens here is called stick and flow, in which the flow of the material comes to a halt (sticking), after which the material starts sliding again (slipping). When this occurs, complete and intermittent slipping over the entire surface of the slip cone shown in FIG. 6B has been reported for high density polyethylene and other such polymer materials, and a similar phenomenon is seen not just with polymer compounds but also in the extrusion of bismuth-tellurium and other such metal materials that are thermoelectric semiconductors, for example. This is manifested as cracks in the extruded semiconductor. Various apparatus improvements have been attempted from a mechanical aspect in an effort to eliminate this problem, but the fact is that the fluid properties of polymer compounds are still not fully understood by researchers.
The materials that are the subject of the present invention are polymer compounds, and it is necessary to understand this phenomenon. Since the present invention involves a plurality of polymer compounds, however, it is uncertain whether the phenomenon witnessed with a single compound such as polyethylene would be the same, and the problem is even more complicated because we are dealing with a mixture in which the temperature dependency of viscosity and the thermal deformation temperature characteristics vary with the different raw material polymer compounds, which probably makes it even more difficult to understand the situation in terms of fluid dynamics or tribology.
The present invention relates to a field of technology in which such scientific understanding is not necessarily perfect, but at the very least, of course, we must know something about the material characteristics of the raw material polymer compounds being used. Let us now give a brief summary of the characteristics of a polypropylene resin, as an example of a plastic resin, and starch, which are believed to be the main contributors to fluidity out of the polymer compound materials used in the present invention.
Starch is usually in the form of macromolecular spherulites of a mixture of two homologues with different structures, amylose and amylopectin. The size thereof can vary greatly with the type of starch, but the diameter is said to range from 1 to 20 microns, and the molecular weight up to a few thousand. Amylose is a linear polymer to which D-glucose units are connected by α-1,4 linkages, whereas amylopectin is a branched polymer that includes α-1,6 linkages in addition to α-1,4 linkages, with branching occurring at these sites and the branches connected again with α-1,4 linkages.
When starch granules are suspended in water and heated to a certain temperature or higher, the starch granules undergo irreversible swelling and amylose is eluted. This process is called agglutination, and this temperature is referred to as the agglutination temperature. FIG. 7 shows published heating and viscosity curves for various kinds of starch (amylograms). The agglutination temperature ranges from 60 to 90° C., and cornstarch is what is cited in the embodiments and so forth of the present invention. FIG. 8 also gives published information, and is a comparison of the viscosity behavior of ordinary wheat resulting from agglutination, by variety of glutinous wheat (which has a relatively high amylopectin content), versus that of cornstarch.
For this comparison, the temperature of each starch was raised from 34° C. to 94° C. at a rate of 5° C. per minute, after which the starch was cooled at the same rate of 5° C. per minute and its viscosity was measured. Of these varieties, Norin No. 61 had the same amylose content of 31.8% as ordinary wheat, and its agglutination temperature was close to that of wheat as shown in FIG. 8. The waxy cornstarch used as a control also has a relatively low agglutination temperature, similar to what is shown in FIG. 7. The purpose of providing FIGS. 7 and 8 here is to show the agglutination temperature of the starch that is one of the polymer compound materials used in the present invention in relation to the fluidity of these materials, and demonstrate that there is a rapid increase in viscosity as soon as the agglutination temperature is attained.
The polypropylene resin will now be discussed. Polypropylene is a crystalline thermoplastic resin made by the polymerization of propylene (C3H6), and is hard and tough, with good resistance to moisture, oils, and solvents. Its heat resistance temperature is said to be 170° C. or lower. Also, there is almost no possibility that a linear polymer compound will undergo cyclization during combustion, and these resins, along with polyethylene and the like, are called polyolefin resins and said to be resins that do not produce dioxins or other harmful substances.
According to disclosed reference materials from polypropylene manufacturers and so forth, the thermal deformation temperature of polypropylene varies somewhat with the structure of the compound, but is said to be roughly 100 to 120° C. FIG. 9 shows an example of the elongation viscosity of the linear (without branches) polypropylene resin used in the examples and so forth of the present invention, and it can be seen that the elongation viscosity at 180° C. quickly disappears in just a few seconds. The reason a foam of a high expansion ratio cannot be produced from a linear polypropylene resin is said to be that the elongation viscosity drops off so quickly and the melt tension is low, and most polypropylene manufacturers produce polypropylene resins having a branched structure by subjecting a linear polypropylene to a special process, and then make a foam with a relatively high expansion ratio from this polypropylene resin with improved elongation viscosity and melt tension. Higher cost is at the present time inevitable with a branched polypropylene because a linear polypropylene must be subjected to a post-treatment step such as electron beam irradiation.
When an attempt is made to produce a foam by mixing and melting a starch and a plastic resin such as polypropylene, the difference between the temperature dependence of the viscosity behavior and the melt temperature of the polymer compounds results in complex fluidity of the mixed materials in the mixing, melting, and extrusion steps during manufacture, and it is not hard to imagine the effect that this has on discharge uniformity. Japanese Laid-Open Patent Application H9-111029 discusses a method for manufacturing a loose polypropylene foam by mixing a polypropylene resin and a starch-based additive into a plant-derived foaming agent such as nonfat powdered milk or bean-curd lees, putting this raw material mixture into an extruder comprising a high-temperature heated cylinder, and feeding in water. This publication also discusses a method in which a plastic component, plant-derived foaming agent, and starch-based additive are simply mixed.
The inventors of the present invention conducted manufacturing tests in which they used an actual foam manufacturing apparatus similar to that in the disclosed information, used as their raw materials a plastic resin, starch, and pulverized waste paper (as the plant-derived fibrous material), and varied the amount of feed water (the foaming agent), the mixing time and temperature in the manufacturing process, the conditions of the material discharge orifice, and so forth. As a result, with a simple mixture of raw materials as in the disclosed information, perhaps because variance in fluidity could not be suppressed, there was considerably fluctuation in the discharge amount per hour, and there was also variance in the foaming state, so it was found that a foam of stable quality could not be manufactured. The specific manufacturing method and steps here are illustrated in FIG. 10.
Pulverized paper (such as waste paper) was used as the plant-derived fibrous material, but first the material was finely pulverized in a mixer/cutter type of pulverizer and then in a ball mill type of pulverizer, this pulverized material was sifted through an industrial sieve to obtain a waste paper powder with particles averaging 20 to 30 microns in size, and this powder was used as the waste paper raw material. This waste paper raw material was then mixed with a polypropylene resin to obtain a raw material mixture, to which cornstarch was further added and mixed, and these components were put in a mixing machine and mixed. The sequence of this mixing was also varied so that the waste paper raw material was first mixed with the cornstarch to obtain a raw material mixture, to which the polypropylene resin was added and mixed in a mixing machine. The mixing was also performed at various blend ratios, including those given in the disclosed information. This kneaded raw material was put into,a biaxial extruder and foamed. Specifically, the biaxial extruder shown in FIG. 11 comprises a raw material inlet 1, a water inlet 2, cylinders C1 to C5, heaters 3 attached to the various cylinders, a raw material extrusion die (spinneret) 4, and an extrusion opening 5. In manufacturing tests, the settings of the cylinder and extrusion die temperatures was suitably varied. The test was conducted with the water supply varied between 10 and 30 liters per hour.
To evaluate the foam state and foam variance, a string-like piece of foam extruded and foamed from an extrusion die with a diameter of 2 mm was cut up by an automatic cutter set to a specific rotating speed, 50 pieces were randomly sampled from among the total of 4200 pieces of cut foam produced in one minute, whose combined length was 120 m, the length and diameter of the cut foam pieces were measured, and the extent of foaming was visually evaluated on a ten-point scale.
The mixing ratios of the materials for which the results are shown in FIG. 14 were 25% (weight ratio) pulverized waste paper, 30% starch, and 45% polypropylene resin.
As indicated by these results, the foam manufactured by the mixing process described above exhibited considerable variance in all measurement categories. The length of cushioning material cut at regular time intervals varied from a minimum of 1.9 cm to a maximum of 8.5 cm. The most serious problem was variance in the extent of foaming. The ten-point scale assumes 10 to be the ideal foaming state, but because there was variance in the foaming, the cushioning material varied from thin to thick. This indicates nothing other than a change over time in the fluidity of the raw material mixture during mixing and melting inside the cylinders. This is similar to the stick and flow phenomenon described above, but it is unclear whether it occurred because a slip cone was formed, or just because of local variance in the fluidity of the molten mixture.
Admixed in this molten mixture was pulverized waste paper, whose characteristics remained almost unchanged over the temperature range in this process. This pulverized paper consists of a fibrous material with a microscopic length of anywhere from a few microns to about 100 microns, which is stirred and mixed in the biaxial extruder, and it seems that nuclear cells that will serve as the nuclei for cells are produced here and there in an agitated fluid in which polymer compounds of different viscosity are admixed. In this situation it is doubtful whether a nice slip cone is being formed as in the above-mentioned reports on polyethylene resins. On the contrary, it seems likely that this nucleus formation is occurring as a result of local variance in the fluidity of the molten mixture.
At this point we will briefly discuss the correlation between the viscosity of the above-mentioned starch and polypropylene resin and the fluidity of the mixture of polymer compounds, since such a discussion will probably further clarify the points involved in the problems which the present invention is intended to solve and the means used to solve the problems. A capillary type of viscosity measurement apparatus is the most commonly used in the measurement of the viscosity of polymers. A sample is extruded from a capillary tube by applying pressure, and the viscosity is measured by measuring the difference in the applied pressure at a constant flow rate per unit of time. We will let L be the length of the capillary tube, and r be its radius. The change over time in the amount of sample flowing out of the capillary tube is found for when pressure is applied such that the sample contained in the reservoir flows at a specific rate, and this is termed Q (cm3/sec). A relationship ofγ=4Q/πr3
exists between the shear rate γ (sec−1) and the sample flowing through the capillary tube, and the shear stress τ (N/cm2) on the inner walls of the capillary tube is expressed as τ=rP/2L. The viscosity μ (N·sec/cm2) is defined from the shear rate γ and the shear stress τ as:μ=τ/γ.
If we assume that a starch and a polypropylene resin are mixed and the thermal characteristics of each are independently manifested, the intrinsic viscosity should be exhibited in the starch at the agglutination temperature and in the polypropylene resin at the thermal deformation temperature, with the viscosity subsequently varying according to temperature changes. For instance, if the agglutination temperature of the starch is reached before the thermal deformation temperature is reached, the viscosity of the starch increases suddenly, and the entire system is governed by the viscosity of the starch. If the thermal deformation temperature of the polypropylene resin is never reached, the polypropylene might have some kind of effect as an admixture, but the viscosity μ of the system will be relatively stable. In other words, this is a state in which the fluidity of the system is governed by the viscosity of the starch, even though the system is a mixture.
However, this never happens for the purposes of manufacturing a foam. Still, if the temperature continued to rise, it would eventually reach the thermal deformation temperature of the polypropylene resin, resulting in a fluid having both the viscosity of polypropylene and the viscosity of the starch, which varies with time and temperature. It is very difficult to know what the mixing state is in a mixed fluid such as this. Measurement was made at a certain specific temperature with the above-mentioned viscosity measurement method, but since the mixing is not completely uniform in a mixing state of different viscosities, the local shear rate γ should vary. Furthermore, the shear stress τ on the inner walls of the capillary tube also varies according to the local mixing state. In other words, the viscosity μ of a mixture of polymer compounds changes with how uniform the mixing is, and if we look at the viscosity definition of the above formula, we can see that there is extreme instability in which both the denominator and the numerator vary. Put another way, there is no viscosity that governs the mixture as a system, and instead the system is in a state of constant change.
Japanese Laid-Open Patent Application 2000-143869, which is another source of disclosed information, discloses a technique of manufacturing a foam by pulverizing a plastic laminate and mixing with polypropylene, cornstarch, and calcium carbonate. With this technique, the foaming expansion ratio is about 10 times with just the resin that is admixed in the laminate paper, and the admixture of another plastic is proposed in order to increase the foaming expansion ratio. Close examination of this technique reveals that, as seen in the embodiments and examples of the invention, a foamable composition is made up of plastic from pulverized laminate paper and added calcium carbonate. Cornstarch and the paper component of plastic laminate paper are added as fillers, the components are stirred and mixed, put into the hopper of an extrusion molding machine, kneaded, heated, melted, and pressurized while water is supplied, and then discharged into the air and expanded to obtain a continuous foam. One way to increase the foaming expansion ratio is to add a plastic material that is miscible with the plastic component of the plastic laminate paper. After the plastic material, organic plant component, and inorganic component are kneaded, water is added as a foaming agent, and it is considered important that the various components be uniformly dispersed if a uniform foam is to be obtained. To this end, it is preferable if discarded plastic laminate paper is pulverized and made into pellets in a pelletizer, to which are added the required amounts of plastic, organic plant component, and inorganic component, the components are stirred and kneaded in a mixer, and the resulting composition is supplied to an extrusion molding machine. With this technique, the manufacturing process is characterized in that the method for mixing the materials involves merely mixing the plastic component, plant component (such as cornstarch or paper), and inorganic component.
Even with this disclosed technique, there is no special technical description of the above mixing step other than to say that the goal is to obtain a uniform form by merely subjecting raw materials of different melting temperatures and viscosities to a kneading step, and achieving the uniform dispersion of the various components. It is obvious that this disclosed information does not solve the problem related to viscosity and fluidity encountered by the inventors of the present invention.
A foam is basically a resource-conserving material in that the amount of materials consumed is extremely small. Foams have excellent adiabatic properties and impact resistance, and are lightweight, which means that they can be used in a wide variety of situations, including applications as packaging materials, and for this reason resin manufacturers and others have conducted intensive research into foams. The flip-side of being lightweight is that foams also have a large volume, so their development requires adequate consideration of their material characteristics as related to recyclability and disposal. As already touched upon in prior art, if a foam could be made from pulverized waste paper or another plant-derived fibrous component or a starch or the like and, if needed, a plastic resin or the like that has been confirmed to be safe to humans and the environment, this would have considerable social significance as well, in view of the high cost of developing new resins and so forth. The present invention solves the problems with viscosity and fluidity inevitably encountered with mixtures of a plurality of different types of polymer compound in the manufacture of a foam by mixing a plastic resin with the above-mentioned natural materials, and establishes a method for manufacturing a foam of uniform quality, with which stable manufacture on an industrial scale is possible.

Process for producing foarmed articles and the foamed article


An AUC-maximized high-accuracy classification method and system for imbalanced datasets integrates an under-sampling-and-ensemble strategy, a true-outliers-removing strategy and a fake-outliers-concealing strategy, with the hope to effectively and robustly enhance both the AUC and the accuracy metrics in imbalanced classification. Applying under-sampling to construct multiple sub-datasets and assembling classification results of multiple classifiers greatly decline the risk of misclassification and lead to highly accurate and robust results in imbalanced classification task. Moreover, this invention pays attention to detect and identify extremely hidden outliers in a sub-dataset which includes a sub-majority dataset and the entire minority dataset. In this way, more hidden outliers can be located and thus exert less influence on the decision boundary, which contributes to both high AUC and accuracy. Furthermore, this invention proposes to conceal fake outliers when building decision boundary, which can achieve a higher classification accuracy of the majority class without changing that of the minority class.

It is widely known that developing a machine learning based system using imbalance data samples is not straightforward. Based on the literature of machine learning research, imbalanced data can be handled by: techniques dealing at the data level (over-sampling or under-sampling) and techniques dealing at the classifier level by modifying the algorithms to suit the imbalanced scenario.
Random under-sampling of the majority-class samples, and over-sampling by duplication of the minority-class samples are two of the simplest ways of dealing with the classification of imbalanced datasets. However, they also produce unwanted effects such as over-fitting or information loss by duplicating or deleting examples respectively, as described by Han et al. [1]. A hybrid technique combines both oversampling and under-sampling. Synthetic Minority Oversampling Technique (SMOTE), as described by Chawla et al. [2], is another frequently used technique where instances of the minority class are synthetically created between samples of the class and their neighbors. Borderline-SMOTE [1] is a modification of the SMOTE technique, where oversampling of the minority-class is performed only for the samples which are close to the decision boundary. This method considers a minority-class instance to be qualified for oversampling with the SMOTE technique if more than a half of its m nearest neighbors come from the majority class.
Costa and Nascimento [3] use weighted data classifiers to deal with class imbalance. Class-specific weights were incorporated in Logistic Regression (Log R) and Support Vector Machine (SVM) classifiers. The weights assigned to the classes were inversely proportional to the number of samples in a class. In the case of random forest and K-Nearest Neighbors (KNN) classifiers, the authors shifted the threshold for predicting a sample. The threshold was shifted according to the proportion of samples in each class. For example, using KNN, if a minority-class sample was among the 60 nearest neighbors, it was classified as positive. In order to deal with missing data, soft-impute, a form of Expectation Maximization based imputation, was employed. Results are reported in terms of miss-classification cost, false positive percentage, and false negative percentage.
Peruffo [4] investigated the use of different entropy measures as indicators of node impurity, in order to decide splitting in a decision tree classifier. The author argued that for imbalanced data, alternative definitions of entropy (instead of traditional Shannon's definition) lead to better measures for splitting. This can lead to improvement in minority-class precision at the expense of majority-class precision. The author tested the entropy measures on the public Air Pressure System dataset. Accuracy, false negatives, and false positives were used as the performance measures.
Rafsunjani et al. [5] investigated five different imputation techniques (Expectation Maximization, Mean Imputation, Soft Impute, Multiple Imputation by Chained Equation, and Iterative Singular Value Decomposition) in conjunction with five different classifiers: KNN, Naive Bayes, Gradient Boosted Tree, Random Forest, and SVM. Their results indicated that Multiple Imputation by Chained Equation was the most effective imputation technique, and random under-sampling was the most effective technique to deal with imbalanced data. In addition to the accuracy, true negatives, false positives, false negatives, and true positives were used as the performance measures.
Ranasinghe and Parlikad [6] investigated the use of Conditional Generative Adversarial Network (CGAN) for generating artificial samples of the minority class. They used the CGAN by sampling from joint distributions of auxiliary information related to failures and noise. APS failure dataset for Scania trucks were used for the experimentation. The authors generated 2000 extra samples for the minority class to be used during training. True positives, true negatives, false positives, and false negatives were used as the performance measures apart from the misclassification cost.
Akarte and Hemachandra [7] employ weighted samples by assigning more weight to the samples of the minority class. The weight was set based on the ratio of the samples of the positive and the negatives classes in the training set. The hyper-parameters were optimized using cross-validation results. Samples with over 70% missing values were removed. Other missing values in a feature were replaced with feature median. True positives, true negatives, false positives, false negatives, precision, recall, F1-scores were used as measures apart from the misclassification cost.
Ertekin et al. [8] considered active learning with online SVM to deal with imbalanced data. Online SVM learns incrementally by adding samples one at a time to the training set. The sample to be added to the training set at a given iteration is selected using the active learning strategy. 59 data points are randomly sampled, and the closest sample to the current boundary is added to the training set. An early stopping criterion is used to stop the training. It is based on the idea that if the number of support vectors stabilizes implying that all the possible support vectors have been selected, then the training can stop.
Nguyen et al. [9] presented the idea of oversampling the minority class only at the borderline between the class samples in order to deal with classification for imbalanced data. Their justification was that the samples that lie close to the border are more important for the classification problem. Hence oversampling should be at the borderline instead of using all the minority-class samples. The presented method was found to be effective when the overlap between the classes is low. Ensemble of under-sampled classifiers is another technique to deal with the imbalanced data (e.g., [10]). As different batches of under-sampled datasets are created, an ensemble seems to perform more robustly as compared to a single classifier. Oh et al. [10] presented an incremental technique based on randomly selecting a balanced subset from the complete data, and then iteratively adding 'useful' samples to the training set. The usefulness of a sample is determined by improvement in the information gain of the classifier by adding that sample to the existing subset of training examples. Diez-Pastor [11] created an ensemble of classifiers termed as RB-Boost. The idea was to combine AdaBoost with random sampling. Here, random sampling refers to the idea that proportion of classes in a training set for an AdaBoost instance is selected randomly. Then, SMOTE is used for augmenting data for a class having fewer samples, and random under-sampling is used for reducing the number of samples for a class having more data. Through these methods, the goal is to achieve the desired ratio between the class samples.
Shao et al. [12] presented Weighted Lagrangian Twin Support Vector Machine (WLTSVM) for dealing with binary classification of imbalanced data. A graph based under-sampling of the majority-class was presented to deal with imbalanced data. Furthermore, weighted bias was introduced to improve the performance of the class that has fewer samples. Maldonado and Lopez [13] presented a new second-order cone programming formulation for SVM to deal with classification of imbalanced data. The approach is based on cost sensitive learning, where cost of misclassifying samples of a minority class are higher than that of the majority class samples, and is performed separately for each class. Linear programming SVM formulation was adapted based on second-order cones and the problem was split into two margin variables.
Kang et al. [14] illustrated a Weighted Under-sampling SVM (WU-SVM) method based on space geometry distance. The key idea in WU-SVM, is to generate Sub-Regions (SRs) by grouping majority samples and assign weights to the majority samples within the SR based to their Euclidean distance to the SVM's decision plane. This is done in-order to retain the data distribution of the original data while under-sampling.
From the literature review, it can be seen that the presence of imbalanced data makes the classification problem a challenging task. Moreover, hidden outliers greatly deteriorate the performance of a classifier. There are many abnormal data in the practical industrial scenarios, most of which come from the sensor reading error or transmission error. Abnormal data that deviates significantly from normal values can be easily removed during data preprocessing. In Kang et al. [15], noise filters are combined with under-sampling technique in-order to handle noise in the minority class. But there is a kind of outliers hidden among normal data: they have normal values from the perspective of the overall data. However, in the view of one cluster, it locates far away from most of the data in the same cluster, which indicates that they are likely to be outliers. As shown in FIG. 1, take an imbalanced binary classification task as the example. The blue circles represent the 10 positive samples and the red plus signs represent the 100 negative ones. It is possible that two positive samples A and B and in the figure are outliers, because almost all of their neighbors are negative samples. Also, the negative sample C is likely to be an outlier since it is surrounded by positive samples. The existence of such outliers greatly affects the decision boundary in imbalanced classification because they can pull the decision boundary to a closer region such that maximum overall accuracy can be achieved. However, under this circumstance, more samples will be misclassified. The invention provides a method and system to improve the accuracy of unbalanced classification by detecting hidden anomalies and then remove true outliers and conceal fake outliers.

AUC-maximized high-accuracy classifier for imbalanced datasets


An apparatus for cryostorage and manipulation of a plurality of container units includes a cryochamber having a cryo-access port. The cryochamber is electrically cooled at cryogenic temperatures. A unit holder is located inside the cryochamber and is configured to hold a plurality of container units. A user access area is provided for selectively permitting access to a chosen container unit by an authenticated user who has been authenticated by the apparatus. A motive grasper is provided for selectively removing the chosen container unit from the cryochamber through the cryo-access port, and selectively placing the chosen container unit into the user access area.

In a medical setting, it is sometimes desirable to securely and cryogenically store substances (e.g., medications or other therapeutics) at extremely low temperatures. For laboratory purposes, liquid nitrogen is often used to achieve appropriate cryogenic temperatures. However, if the cryo-stored substance is a dispensed material for provision, e.g., outside a laboratory setting, it may need to be stored in a pharmacy or storeroom that does not have available liquid nitrogen or cryo-trained personnel. In this case, individual containers of the substance may be provided for single-use dispensing, but access to one container should avoid undesirably warming other stored containers.
In addition, depending upon the nature of the substance, there may be access control and security issues related to the storage and dispensing. For example, the temperature, lot number, expiration date, or other information of a particular container or other unit of the substance may be important to monitor or track. As another example, the substance may need to be dispensed by special permission (e.g., prescription-only), and/or to be tracked for billing purposes. The storage temperature may be monitored and fluctuations detected and addressed.
Finally, it may be desirable, in some use environments, for the substance to be warmed from the cryogenic temperatures before being provided to a user in a controlled manner. For example, for some stored substances, facilitating the transition from frozen to liquid form may be important in maintaining useful value of the substance, which may be rare, fragile, and/or expensive to replace if damaged during thawing. Particularly when the user is not a trained cryo-technician, it may be helpful for the access control procedures to prevent the user from contacting the substance (or a storage structure) which is held at cryogenic temperatures.

Apparatus and method for cryostorage and manipulation of a plurality of container units


Process measurement may be achieved by systems and techniques generating output signals based on the measured process. In certain implementations, process measurement systems and techniques may include the ability to generate a magnetic field and successively change the orientation of the magnetic field. The systems and techniques may also include the ability to sense the presence of at least a first orientation of the magnetic field with a magnetic field sensor including a conductor and at least two Wiegand-effect conductors as the magnetic field orientation is changed and to generate an electrical pulse in the conductor with each Wiegand-effect conductor when the first orientation of the magnetic field is sensed.

Process measurement devices and techniques are used in a wide variety of environments for commercial and industrial applications. For example, process measurement devices and techniques may be used for monitoring pressure, temperature, and/or flow rate in pipelines or storage facilities. In many of these environments and applications, it is not uncommon for a process measurement device or technique to have difficulty in accessing an external power supply. Also, for environments and applications that require intrinsically safe devices or techniques, external power supplies are commonly disfavored. Thus, process measurement devices and techniques that do not require an external power supply are often quite beneficial.
Process measurement devices and techniques may generate their own power by any of a variety of methods. For example, a process measurement device may have an internal power supply (e.g., a battery). As another example, a process measurement device may generate power from the measured process, by using a small amount of momentum, for instance.

This patent is subject to a terminal disclaimer.

System and method for process measurement