A fuel cell power supply system includes a fuel cell and a converter which converts the DC output power of the fuel cell into the corresponding AC output power. A reduced-size converter or invertor may be employed by following the sequence consisting of checking to see whether there is an open-circuit voltage at the start-up of the fuel cell, followed by reducing the voltage across the fuel cell by using a discharging resistor and then rendering the converter or inverter operational. A switch is included, which is normally closed and selectively connects the discharging resistor and the fuel cell in parallel. This allows the fuel cell to continue to discharge when the fuel cell or system has been terminated normally or in case the appropriate control power supply should fail. The fuel cell is thus protected against any degradation that may occur due to any residual FC gas that may remain in the fuel cell and conduit passages, by allowing any voltage caused by the residual FC gas to discharge rapidly.

1. Field of the Invention
The present invention relates to a fuel cell power generator system, more particularly to a method of and an apparatus for controlling the output voltage of the fuel cell in that type of power generator system.
2. Description of the Prior Art
The output voltage of a fuel cell may typically have its value varying greatly, depending upon whether the fuel cell is actually supplying its power to any particular load or not.
It is also known that the fuel cell will degrade if it is left in its high voltage level (such as above 0.8 Volts per cell), and it will also degrade due to the reversed polarity effect that may occur if the fuel cell is at its low voltage level.
The power generator system that employs the fuel cell converts a DC electrical power supplied by the fuel cell into a DC power or AC power by using any appropriate DC-to-DC converter or DC-to-AC converter, so that either of the converted currents can be supplied to its attached load. As the output voltage of the fuel cell may vary greatly as described above, the DC-to-DC converted or DC-to-AC converter includes a power element which usually have a high withstand voltage property.
When the fuel cell is left in its high voltage state, an electrochemical reaction may be caused by any residual gases that remain in the fuel cell if the power generator system is stopped (therefore the converter is also stopped). This reaction produces a high voltage when the system is placed under no load condition. In the prior art, a discharging circuit is incorporated in the power generator system to remove the high voltage as soon as it is produced by the reaction.
When the discharging circuit is used to remove the high voltage, it must be controlled by its own power supply, and this control power supply is typically provided from any external power source. It should be noted, however, that for a mobile fuel-cell power generator system, it would be practically difficult to use the external power source as such control power supply.
The power generator system that employs the fuel cell (which will be referred to hereinafter as "FC") may typically be started up or stopped in the manner as shown in FIG. 1. The curves 401, 402, and 403 shown in FIG. 1 represent the respective changes over a given time in the FC voltage, the FC current, and the amount of the FC introduced gas. The FC rising temperature period (t1) corresponds to the period from the moment that the FC1 is started up until the moment that any FC gas, such as fuel gas and oxygen gas is to be fed into FC1. Once any FC gas is fed into the FC1, the FC voltage is increasing rapidly. The FC open-circuit voltage checking period (t.sub.2) corresponds to the period from the moment that the gas has been fed into the FC1 until the moment that the FC1 generates electricity and is beginning to supply the generated electricity.
The generated power increasing period (t.sub.3) corresponds to the transitional period from the start of the power supply until the moment that the power supply can become constant. During the following period (t.sub.4) when the particular power requirements may be supplied, the power will be provided from the FC1 in the constant manner. The final-stage period (t.sub.5) corresponds to the time that may be required from the moment that the FC gas has ceased to be fed, causing the FC1 to stop its power supply until the moment that the FC voltage is falling to approximately zero (0).
Those segments designated by A, C, and b, respectively, in FIG. 1 will be described later by referring to FIGS. 4 and 5.
The sequence of starting up and stopping the known fuel-cell power generator system as described above and shown in FIG. 1 may be used in the plant facilities, regardless of their running capacities. Specifically, the sequence of starting up may be found in the publication "FUJI JIHOU Vol. 61, No. 2, 1988, 156 (40) page, Japan". The following describes some of the prior art sequences of producing a DC power in the fuel cell and converting the DC power into the required power to be supplied to any particular load.
The sequence that is implemented by the circuit shown in FIG. 2 consists of allowing FC1 to provide a DC power output and then allowing an invertor (INV) 2 to convert the DC power output to the corresponding AC power which is to be supplied to a particular AC load 3 or other operational systems 4.
The AC power output of the invertor 2 is delivered to a filter (FL) 5 and then to a transformer (TR) 6, from which the AC power will be supplied to the AC load 3 or other operating systems 4 when an output switch (SW.sub.AC) 7 is placed in its "ON" position. In FIG. 2, reference numeral 8 refers to a main switch (SW.sub.M), 9 refers to a discharging resistance switch (SW.sub.R), and 10 refers to a discharging resistor (RD).
The circuit shown in FIGS. 3A and 3B includes a step-up chopper 11 that provides the DC-to-DC conversions in response to the DC power output from the FC1. Those parts or elements which are similar to those shown in FIG. 2 are given the same reference numerals in FIGS. 3A and 3B. Specifically, the circuit arrangement shown in FIG. 3A includes a backup battery (B) 15 which permits the fuel cell power generator system to be operational in the hybrid manner and to provide a DC power to any particular DC load 3A.
FIG. 3B illustrates a circuit arrangement that includes the step-up chopper 11 of FIG. 3A that provides the DC-to-DC conversions and an invertor 2A that provides an AC power in response to the DC power output of the step-up chopper 11 of FIG. 3A and a filter 5A that provides an AC output to the AC load 3.
FIG. 4 shows the characteristic curves for the fuel cell shown in FIG. 2. In FIG. 4, a curve 701 represents the relationships between the FC current I.sub.F and the FC voltage V.sub.P. A curve 702 represents a 100% load resistance line, which may be obtained by connecting the origin and the rated point N at the time when an FC rated current value b is given along the curve 701. The value of the FC voltage that may then be developed is represented by C.
A line 703 represents changes in the discharging resistance, which may be drawn by connection the origin and the point N' at the time when the FC1, the SW.sub.R 9, and the RD10 forms a closed circuit. At point N', an FC current value a is provided, A line 704 represents a resistance line when the FC current value a' is given along the curve 701. At the point N', FC voltage B' may be developed.
As it may be seen from FIG. 1, the invertor 2 must be able to start at the moment when the power is to be supplied, and must have the ability to provide a current flow equal to the current value b during the period (t.sub.4) from the start-up time to stop time. In other words, the invertor 2 must meet the requirements for the capacity, which may be represented by the area delimited by the original and the points A, O, and b in FIG. 4.
FIG. 5 shows the characteristic curves for the fuel cell shown in FIGS. 3A and 3B. Those lines or curves which are similar to those shown in FIG. 4 are given the same reference numbers in FIG. 5. In FIG. 5, reference numbers 801, 802, 803, and 804 correspond to the lines or curves 701, 702, 703, and 704, respectively. The curve 805 explains the relationships between the battery current I.sub.B and the battery voltage V.sub.B.
As it may be seen from FIG. 1, the FC voltage is gradually increasing during the period t.sub.2 until it has become higher than the battery voltage F as shown in FIG. 5 when the step-up chopper 11 has stopped. Although the step-up chopper 11 is inoperational during that period, a current can still flow through the FC1, a coil L, and a diode D into the battery 15, or the load 3A or 3. The step-up chopper 11 should start at the time when power is to be supplied as shown in FIG. 1, and must meet the requirements for the capacity, which may be represented by the area either delimited by the origin and the points A, O and b, or the origin and the points F, O" and b in FIG. 5.
At the start-up of the fuel cell, the open-circuit voltage checking period (t.sub.2) in FIG. 1 corresponds to the period during which checking is made to see whether any problem has occurred within the FC gas supply system by determining that the FC generated voltage has increased above the prescribed voltage value. During this stage, any means should be provided to allow such checking to occur under no load condition in order to determine whether there is any problem with the FC gas supply system.
If a problem has occurred within the FC gas supply system, the FC generated voltage will fall. In this case, if power is supplied to the load 3 or 3A, the FC generated voltage will fall. In this situation, it would disadvantageously be impossible to check to see accurately if there is any problem with the FC1.
As it may be understood from FIG. 1, when the system is stopped, the FC gas supply will also be shut down. In this case, some of the FC gas may possibly remain within the FC1 and its associated conduit passages, causing some voltage to be developed. Therefore, means such as the open-circuit capacity converter should be provided in the FC1.
Another disadvantage of the prior art is the use of the power element that has a high withstand voltage property as one of the component parts of the converter. Using such power element increases the physical dimensions of the converter, and reduces its efficiency of conversion.

Method and apparatus for controlling a fuel cell


An apparatus and method shares predictive failure information between computer system in a computer network. The shared predictive failure information allows dynamically rerouting a network request to avoid a computer system that may fail according to its predictive failure information. According to a first embodiment, if the requested resource on the network has predictive failure information that indicates the resource may soon fail, a message is returned to the requesting computer with information that includes possible alternative sites from which the information may be obtained. If there is an alternative site, the requesting computer system may access the alternative site, thereby avoiding the computer system that may soon fail. If there is no alternative site, the requesting computer system may return an error message, or may simply access the original resource on the chance that is has not yet failed. According to a second embodiment, a router in the network may indicate one or more alternative paths to a resource if the predictive failure information for the router indicates it may soon fail. The requesting computer system may then access the requested resource via the alternative path. In this manner, predictive failure information can be used in rerouting network traffic between computer systems on a network to minimize the effect of a failing computer system.

1. Technical Field
This invention generally relates to data processing, and more specifically relates to apparatus and methods for predicting failures in networked computer systems and acting on the predicted failures.
2. Background Art
Electronics and computers have greatly enhanced worker productivity in our modern information age. Much attention and many resources have been directed to making electronic and computer systems more reliable. When an electronic component or system fails, it can lead to system-wide failures that can cost companies millions of dollars. In such a context, it became necessary to prevent system failures.
Early attempts at preventative maintenance simply replaced certain components after a specified period of time in use. While this approach is effective if the time periods are selected with care, it is also very expensive, and leads to replacing components that do not need to be replaced. Some individual components can perform without problems for much longer than the mean time of operation without failures. By replacing components that do not need to be replaced, the cost of maintenance becomes excessive.
Another approach to preventative maintenance is to monitor components and replace a component when its operating parameters indicate that it may fail soon. This approach was pioneered by IBM in the early 1990s, and led to a concept referred to as Predictive Failure Analysis (PFA). Predictive failure analysis was first applied to hard disk drives. PFA status is in a normal state when the disk drive is operating correctly, and is in a "tripped" state when the PFA in the drive indicates that a failure will occur soon. A hard drive that has PFA capability monitors its internal functions, and indicates when the functions are outside of predefined limits by "tripping" a signal that indicates that the disk drive is about to fail. For example, a PFA status may be tripped if the fly height of a head is outside of specified limits, or if the error rate in the hard disk drive exceeds a specified limit. By indicating via the PFA status on a disk drive that a failure will likely happen soon, the system administrator has enough time to copy the contents of the disk drive to a backup source, replace the drive, and write the data from the backup to the new drive. PFA is thus an important tool that allows replacing a disk drive that may fail soon without loss of data.
Recognizing the value of predicting failures in disk drives, some competitors of IBM have implemented disk drives that have a S.M.A.R.T. interface, which stands for Self Monitoring And Reporting Technology. The S.M.A.R.T. interface is a specification of a set of registers in a device that contains information relating to the device's operation. No details are provided regarding the specific types of measurements that should be made or the values that indicate an impending failure. For this reason S.M.A.R.T. compatible disk drives are much less sophisticated that IBM disk drives that include Predictive Failure Analysis.
Predictive Failure Analysis has been implemented into components such as disk drives and printers. Communication of information relating to predicted failures has been limited so far to the box-level of a computer system, which means that a component inside a computer reports predictive failure information within its own box, but this information has typically not been used or communicated outside of a particular computer system. With the popularity of computer networks, it would be useful to share predictive failure analysis information between computer systems on a network. Furthermore, by detecting when certain computer systems may fail, it may be possible to re-route a network request to avoid a computer system or network path that may fail according to its predictive failure information. Without an apparatus and method for communicating predictive failure information between computer systems on a network and for dynamically rerouting a network request to avoid computer systems and network paths that may fail, the computer industry will continue to suffer from predictive failure information that is isolated within a system, with the result that failures that were predicted in individual computer systems may cause errors in inter-system communications over the network.

This patent is subject to a terminal disclaimer.

Apparatus and method for dynamically rerouting a network request based on shared predictive failure information

International Business Machines Corporation


A substrate-supporting apparatus, wherein a substrate is not warped or distorted and a film with uniform thickness is formed, is a semiconductor substrate-supporting apparatus which supports and heats semiconductor substrates inside a vacuum-pumped reaction chamber. On the substrate-supporting surface of the semiconductor substrate-supporting apparatus, a concave portion which includes a depression slanting from the peripheral portion to the center is provided, the semiconductor substrate is supported in a position where the peripheral portion of the back surface of the substrate contacts the slanting surface of the concave portion, and the concave portion is formed so that an interval between the center of the concave portion and the semiconductor substrate becomes the designated distance. The slanting surface of the concave portion may include a portion of a spherical surface or a conical surface.

1. Field of the Invention
The present invention relates to a semiconductor substrate-supporting apparatus which supports and heats semiconductor substrates inside a vacuum-pumped reaction chamber, and particularly relates to a semiconductor substrate-supporting apparatus which is characterized by the shape of the surface supporting the semiconductor substrate.
2. Description of the Related Art
Conventionally, using CVD equipment, silicon oxide, silicon nitride, insulation films such as polymers containing amorphous carbon or benzene nucleus, conductor films such as tungsten silicide, titanium nitride or aluminum alloy and highly-dielectric films including PZT(PbZr1xe2x88x92xTixO3) or BST(BaxSr1xe2x88x92xTiO3) have been formed on silicon substrates or glass substrates.
To form these films, the low-pressure thermal CVD method and the plasma CVD method are generally used. In the low-pressure thermal CVD method, however, there is a problem that the electrical property of a semiconductor element changes by heat load and does not function as designed, because the semiconductor substrate is exposed to a high temperature above 700xc2x0 C. As semiconductor apparatuses become more highly integrated in recent years, this heat load problem becomes increasingly serious. For this reason, the plasma CVD method, which reduces heat load to the substrate by processing the substrate at a low temperature, has become the mainstream method.
Generally in plasma CVD equipment, a substrate is heated and held at approximately 250xc2x0 C. to 600xc2x0 C. by a ceramic heater heated at 300xc2x0 C. to 650xc2x0 C. The ceramic heater also functions as a susceptor which directly supports the substrate. The ceramic heater is made by burying a resistance heating element and a radio-frequency electrode in the base substance comprising aluminum nitride (AlN). The radio-frequency electrode is embedded at a position which is approximately hundreds to thousands of xcexcm deep from the heater top surface, which directly contacts the semiconductor substrate.
Conventionally, the following have been reported regarding the shapes of the surface of a ceramic heater: U.S. Pat. No. 5,231,690, U.S. Pat. No. 5,968,379 and Japanese Patent Laid-open No.2000-114354 disclose a ceramic heater whose surface is smoothly finished so that the surface of the ceramic heater and the back surface of the substrate perfectly contact. According to this, heat is efficiently conducted from the ceramic heater to the substrate. U.S. Pat. No. 5,306,895, Japan Patent No.2049039 and Japanese Patent Laid-open No.1995-238380 disclose a ceramic heater on whose surface a concave portion with a bore size smaller than the diameter of the substrate is formed and which contacts the back surface of the substrate only at the peripheral portion of the back surface of the substrate. According to this, because thermal conduction from the ceramic heater to the substrate is achieved only at the peripheral portion of the substrate, lowering the temperature at the peripheral portion of the substrate is prevented.
In the case of a ceramic heater whose surface is smoothly finished, because heat rapidly flows into the back surface of a substrate from the ceramic heater immediately after the substrate is placed onto the ceramic heater surface, only the back surface of the substrate expands, causing the substrate to warp. Due to this warping, thermal conduction from the ceramic heater rapidly decreases. It requires several minutes until the warping subsides and the substrate becomes flat. Additionally, it requires more time for the substrate to reach a desired temperature. As a result, it takes time until deposition starts after the substrate is placed onto the ceramic heater, and in the case of single-wafer-processing type semiconductor-manufacturing equipment, productivity is remarkably lowered. If the time for heating the substrate is shortened, because a film is formed in the state where the substrate has not reached the stated temperature, the film with the properties as designed is not obtained. If plasma is discharged while the substrate is warped and deposition is performed, plasma energy converges only on the peripheral portion of the substrate, which projects in the discharge space, and the film thickness becomes uneven across the entire substrate.
In the case of a ceramic heater on whose surface a concave portion with a bore size smaller than the diameter of the substrate is formed, because a rate of heat flowing in the substrate can be reduced due to thermal conduction to the substrate taking place only from the back surface of the peripheral portion of the substrate, warping of the substrate is prevented. If the bore of a concave potion is small, however, an area in which the ceramic heater surface and the back surface of the substrate contact becomes large and the contacting portion is rapidly heated locally and thermally expands. As a result, the entire substrate is deformed and warped. Conversely, if the bore of a concave potion is large and approaches the diameter of the substrate, the back surface of the substrate is not rapidly heated, but there is a risk that the end portion of the substrate may fall into the concave portion of the ceramic heater. If the substrate is placed off-center of the ceramic heater due to a position shift, etc., one end of the substrate falls into the concave portion and the substrate tilts with the opposite end projecting upward. If plasma processing is started in this position, abnormal convergence of the plasma energy (arc) occurs, normal plasma discharge cannot be maintained and a film with uneven thickness and abnormal properties is formed.
Consequently, the object of the present invention is to provide a substrate-supporting apparatus with which no warp or distortion of the substrate occurs and a film with even thickness is formed.
The second object of the present invention is to provide a substrate-supporting apparatus which heats a semiconductor substrate rapidly to a desired temperature and increases the productivity of semiconductor-manufacturing equipment.
The third object of the present invention is to provide a substrate-supporting apparatus which prevents abnormal plasma discharge and which provides stable deposition from a process point of view.
To achieve the above-mentioned objects, the semiconductor-supporting apparatus according to the present invention comprises the following structures in an embodiment:
A semiconductor substrate-supporting apparatus which supports and heats semiconductor substrates inside a vacuum-pumped reaction chamber, wherein on a substrate-supporting surface, a concave portion which comprises a depression slanting from the peripheral portion to the center is provided, the semiconductor substrate is held in a position where the peripheral portion of its back surface contacts the slanting surface of the concave portion, and the concave portion is formed so that an interval between the center of the concave portion and the semiconductor substrate becomes the designated distance.
Preferably, the slanting surface of the concave potion may be a portion of a spherical surface, but can be a conical surface as well.
Specifically, the designated interval between the center of the concave portion and the semiconductor substrate may be 0.05 mm to 0.3 mm.
Preferably, the semiconductor-processing equipment may possess a lip portion which protrudes in a ring-shape at its peripheral surface portion.
For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described above. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiments which follow.


A valve sealant fitting includes a spring coupling unit having an internal screw thread for coupling unit assembly below the ball installation groove of the sealant body, the internal screw thread having a hexagonal groove for preventing a downward separation of the coil spring, allowing a fluid to flow and facilitating fastening and releasing of the screw, and having an external screw thread at an outer circumference of the spring coupling unit, and outer sealing O-rings disposed in O-ring installation grooves formed on respective upper and lower positions of the valve coupling taper screw part formed on the outer lower side of the sealant body.

When a leakage typically occurs on a high pressure value or a low temperature valve mounted in a pipe line for gas or fluid (e.g., petrochemical material or the like) due to abrasion or scratch of a sealing portion within the valve, emergency measures are taken by mounting three or four sealant fittings in one valve to allow not only a sealant for fluid interception to be rapidly injected but also a lubricant for keeping smooth operations and functions of the valve to be filled/injected if necessary.
In the meantime, according to the conventional sealant fitting, a sealant injection groove having a small diameter is disposed on an inner upper side of the body of the sealant fitting and a ball installation groove having a relatively large diameter is disposed below the body. A metal ball is closely adhered between the sealant injection groove and the ball installation groove and then a ball seat and a coil spring are disposed below the metal ball to allow the sealant to be injected and to facilitate performing a function of preventing a fluid back-flow. The body at the bottom surface of the spring is press-bent to form a sustaining part for preventing the spring from being deviated downward. A protrusion is formed at an upper portion of the body, which is unfastened when the sealant needs to be injected and is fastened (by cap nuts) to block the injection port when the sealant injection is completed. In addition, a punched vent cap is coupled to a vent groove by screws for smoothly discharging an internal air at the time of fastening operation, and a screw coupling part capable of being coupled to a large-sized valve by screws is formed at an outer lower side of the body.
However, according to the conventional sealant fitting as described above, the press-bent sustaining part for mounting the spring in the fitting, preventing the spring from being deviated and sustaining the bottom surface is disposed on the body at the bottom surface of the spring, so that the sustaining part is structurally weak. Such a sustaining part does not cause a significant problem when it is applied for a low pressure valve. However, the reliability of the sustaining part as a component of a high pressure valve or an ultra-low temperature valve is degraded when it is applied for the high pressure valve due to a high possibility of having cracks or damages in use.
In addition, the conventional sealant fitting is focused on the injection of sealant or lubricant that passes through the internal sealant injection groove and the installation groove, so that a possibility of allowing the fluid to be leaked or flown out of the outer screw part disposed at the lower position of the body still exists.
That is, even when an external screw thread of the lower screw coupling part disposed for easy coupling of the sealant fitting at a predetermined position of the valve is coupled with an internal screw thread of the valve by a strong coupling force, fine gaps and corrosion may occur when a high valve pressure is applied thereto or when the valve is used for a long time, resulting in a leakage of sealant, lubricant, fluid or gas.
In the meantime, many times, processes and costs are required for processing and manufacturing the vent cap and the ball seat among the components of the conventional sealant fitting, thereby decreasing the productivity, economical efficiency, quality and safety thereof.
That is, according to the vent cap among the components of the sealant fitting, its outer shape is of a hexagon nut as shown in the drawing, its each edge is chamfered, it has a coupling groove with a constant diameter therein, an internal screw thread formed on an inner wall of the coupling groove, a protrusion formed on its inner upper central end, and one or more vent grooves formed on its upper end.
To process this, an annular rod (including a hexagon rod) formed of a stainless or cast steel is first cut by a constant length, and twelve processes including a process for hexagon nut head of an outer surface of the vent cap, a process for upper edge, a process for lower edge, a chamfering process for hexagon nut head, a primary groove process for forming an inner coupling groove, a secondary groove process for forming a protrusion, a fine process for protrusion, a process for internal screw, a process for vent groove, a face milling process for upper surface, a face milling process for lower surface, and so on are carried out using a metal cutting tool such as shelf, milling or the like, so that many times and costs are unnecessarily consumed for the processing and manufacturing.
A process for internal groove, a process for lower spring sustaining part, a process for forming a groove for closely adhering the ball and the fluid communication, a chamfering process and so on are also required for processing the internal groove formed in the ball seat, the lower spring sustaining part, and the groove for closely adhering the ball and the fluid communication of the ball seat among the components of the sealant fitting, so that many processes and costs are consumed to decrease the economical efficiency and the price competition.
In addition, when the vent cap and the ball seat are manufactured using the conventional tools, the process quality is finely changed per each product when the process environment, an operator, an abrasion state of the tool or the like is changed, so that the quality safety and the uniformity are also degraded.
Further, the metal ball as an essential component for blocking or adjusting the fluid communication among the components of the sealant fitting is formed of a metallic material, so that it is very difficult to meet an accurate criteria such as the deviation from sphere, thereby not only limiting the function of blocking the fluid but also causing a high possibility of having scratches when the metal ball is in contact with other metal components.

Manufacturing method of valve sealant fitting


An information handling system includes a backplane, a storage drive, and a board management controller. The board management controller is configured to discover a physical drive status of the drive from a storage enclosure processor, to receive a logical drive status of the drive, to read a backplane bay identification for the drive from a peripheral connector interface express extender or serial attached small computer system interface chipset logical drive number, and to construct a routing table for the drive to map the logical drive status with the physical drive status of the drive.

As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option is an information handling system. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes. Because technology and information handling needs and requirements can vary between different applications, information handling systems can also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information can be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems can include a variety of hardware and software components that can be configured to process, store, and communicate information and can include one or more computer systems, data storage systems, and networking systems.
An information handling system, such as a server, can include modular hot-plug storage backplanes so that multiple storage drives with different storage technologies can be connected to the information handling system. The drives connected to the backplanes can be serial advanced technology attachment (SATA) drives, serial attached small computer system interface (SAS) drives, peripheral connector interface express (PCIe) solid state drives, or the like. The backplanes can be managed by an SAS/SATA chipset, software redundant array of independent disks (RAID) controllers, or the like. A board management controller of the information handling system can be a proxy between the managing device and the backplane processors to enable the routing of traffic between a host of the information handling system and the storage drive.
The use of the same reference symbols in different drawings indicates similar or identical items.

System and method for mapping a logical drive status to a physical drive status for multiple storage drives having different storage technologies within a server


A process for producing compound 1,4,7,10,13,16,21,24-octaazabicyclo[8.8.8]hexacosa, 4,6,13,15,21,23-hexaene (2) and then compound 1,4,7,10,13,16,21,24-octaazabicyclo[8.8.8]hexacosane (1) from compound (2) is described. The process uses a reaction between triaminoethylamine and glyoxal in the presence of water, alcohol and tertiary amine at low temperature to produce compound 2. Then compound 1 is produced from compound 2 by reduction with an alkali metal containing ammonia as the reductant. The compounds are aza cryptands which are used to bind metals and the like for electrides, and in alkalides, medicine and water treatment, for instance.

(1) Field of the Invention
The present invention relates to processes for the preparation of 1,4,7,10,13,16,21,24-OCTAAZABICYCLO[8.8.8]HEXACOSANE (H6Aza222) (1) and 1,4,7,10,13,16,21,24-OCTAAZABICYCLO[8.8.8]HEXACOSA, 4,6,13,15,21,23-HEXAENE (2). In a preferred process, the present invention relates to the preparation of compound (2) by reacting tris(2-aminoethyl) amine (tren), isopropyl alcohol (i-PrOH), and triethylamine (Et3N) with cooling at a temperature below −30° C. Further, the present invention relates to the preparation of compound 1 from compound 2 by reacting an alkali metal and ammonia with compound 2 with cooling to a temperature below −30° C.
(2) Description of Related Art
Aza containing cryptands are known in the art and have a variety of uses as noted in U.S. Pat. No. 4,888,032 for instance. Such uses include, for instance, medical uses, water purification removing toxic heavy metals, binding metals as catalysts, electrides and alkalides. They are analogous to the non-aza cryptands of U.S. Pat. No. 4,257,955 to Gansow et al and U.S. Pat. No. 5,492,879 to Dye.
There is interest in nitrogen-donor cryptands for the preparation of room-temperature stable alkalides and electrides (Kim, J., et al., J. Am. Chem. Soc., 121 10666-10667 (1999)) which led to reinvestigation of the synthesis of 1,4,7,10,13,16,21,24-octaazabicyclo[8.8.8]hexacosane (1), the aza analog of cryptand [2.2.2] (Xie, Q., et al., J. Am. Chem. Soc. 122 6971-6978 (2000)). Compound 1 was used for the preparation of the first barium sodide (Redko, M. Y., et al., JACS 125 2259-2263 (2003)). A reaction sequence in which tren is condensed with glyoxal to form the intermediate 1,4,7,10,13,16,21,24-octaazabicyclo [8.8.8]hexacosa-4,6,13,15,21,23-hexaene (2) has been described by Smith et al (Smith, P. H., et al., J. Org. Chem. 58 7939-7941 (1993)), who also obtained the crystal structures of both compounds 1 and 2. While this method is satisfactory, it leads to gelatinous byproducts which lowered the yield and required the separation of compound 2 from the gelatinous byproducts via a 3-day Soxhlet extraction followed by filtration. The gels are polymers formed from the reactants and are very difficult to separate from the compound 2. The purified compound 2 was then reduced with LiAlH4 in THF or NaBH4 in MeOH to give a low overall purified yield of 45% of compound 1. A large excess of moderately expensive reducing agent(s) is required.

Board of Trustees of Michigan State University


Apparatus, methods, and computer program products are disclosed that enable a first computer and a second computer to mutually authenticate each other over a network. A first computer sends first authentication evidence to a second computer. The first authentication evidence is used to prove to the second computer that the first computer has access to a first plurality of authentication secrets without exposing the first plurality of authentication secrets. In addition, the second computer sends second authentication evidence to the first computer. The second authentication evidence is used to prove to the first computer that the second computer has access to a second plurality of authentication secrets without exposing the second plurality of authentication secrets. The first plurality of authentication secrets is related to the second plurality of authentication secrets. Thus, the first computer is authenticated to the second computer and the second computer is authenticated to the first computer.

1. Technical Field
The disclosed technology relates to the field of computer authentication technology.
2. Related Art
Two major security problems on the Internet are phishing and spyware. Phishing, or server impersonation, occurs when a malicious server convinces a user to reveal sensitive personal information, such as a username and password or other secrets, to a malicious server instead of the server to which the user intended to connect; the malicious server can then use the user's secrets to impersonate the user to the intended server. Additionally, many users' computers are compromised with spyware, which can record users' keystrokes (and thus passwords or other secrets) and again provide this information to a malicious party.
While wide-spread use of certificates obtained through a public key infrastructure (PKI) would obviate these problems the public has not embraced PKI technology. Thus, it is difficult to create a secure channel between a user's client computer and a server system using PKI technology. Several techniques are currently used that are intended to address phishing attacks. For example, physical devices that generate one-time passwords can be used to secure corporate virtual private networks (VPNs) and online banking sessions; server-side multi-layer techniques using additional attributes, such as HTTP cookies, IP address, and browser user agent string, can also be used. These techniques can offer greater assurance as to the identity of the user but, even when deployed over today's web security protocol HTTPS/TLS, remain susceptible to sophisticated impersonation attacks, because the protocols underlying these techniques do not protect authentication secrets or provide strong protocols for client-to-server and server-to-client authentication. In addition, many server systems require a login ID that is difficult to guess, such as a fixed-length string of digits or a combination of alphanumeric characters. But, these login IDs are not easily human-memorable and are difficult to use.
Password-authenticated key exchange is a strong technique to defend against impersonation (phishing) attacks and provide server-to-client authentication, but current protocols depend solely on a long-term password, which can be risky when used on a spyware-infested computer, as the long-term password can be captured and misused by others.
Authentication secrets can be classified as being within an authentication factor. Commonly used authentication factors include: something that a user has, something that a user knows, and something that a user is or does. Multi-factor authentication requires that information from two or more of these authentication factors be used to authenticate the user and server system (that is, the use of multiple information that is classified under the same authentication factor is not multi-factor authentication). Multi-factor authentication adds a further degree of assurance to the authentication procedure. Long-term passwords are easily memorized, infrequently changed, and are used repeatedly. One-time responses are used once, change frequently and, though not easily memorized, can be provided by a small electronic token or a sheet of paper. These factors offer different but complementary resistance to different types of compromise. Together, they offer more assurance in authentication because stealing the long-term password alone (for example, by installing spyware) or losing the one-time password card alone is insufficient to compromise the authentication procedure.
FIG. 1 illustrates an existing security vulnerability 100 when current computer authentication technology is used. Here, a user of a client computer system 101 desires to make a connection to an intended host system 103. However, an adversary system 105 exists that can intercept and forward communication between the client computer system 101 and the intended host system 103 using a man-in-the-middle (MITM) attack. Thus, instead of the client computer system 101 and the intended host system 103 establishing an intended network connection 107, they have established a first adversary network connection 109 between the client computer system 101 and the adversary system 105, and a second adversary network connection 111 between the adversary system 105 and the intended host system 103. Once the adversary system 105 is in the communication path between the user's client computer system 101 and the intended host system 103, the adversary system 105 can capture and misuse the user's secrets.
This vulnerability results from the adversary system 105 being able to fool the user into thinking that the adversary system 105 is the intended host system 103 so that the user establishes the first adversary network connection 109 and makes it secure (thus mimicking the intended host system 103). Once the user has established the first adversary network connection 109 (thinking that he/she has established the intended network connection 107), the adversary system 105 then captures authentication secrets from the user and uses the captured authentication secrets to establish the second adversary network connection 111 and impersonate the user to the intended host system 103. Information sent by the user is captured by the adversary system 105 and forwarded to the intended host system 103, and responses from the intended host system 103 are likewise captured by the adversary system 105 and forwarded to the user. Thus, the user's authentication secrets and other private information are exposed to the adversary system 105. In addition, the adversary system 105 has gathered significant authentication data (account, long-term password, challenge/response information, etc.). Other vulnerabilities exist if the intended host system 103 maintains a readable, guessable, or otherwise cryptographically easy password database.
Password-authenticated key exchange was first introduced by in 1992 (Steven M. Bellovin and Michael Merritt. Encrypted key exchange: Password-based protocols secure against dictionary attacks, In Proceedings of the 1992 IEEE Computer Society Conference on Research in Security and Privacy, May 1992) in the form of encrypted key exchange (EKE), a protocol in which the client computer and server system shared the plaintext password and exchanged encrypted information to allow them to derive a shared session key.
Bellovin and Merritt introduced an Augmented encrypted key exchange: a password-based protocol secure against dictionary attacks and password file compromise, Technical report, AT&T Bell Laboratories, c. 1994. The augmented EKE removed the requirement that the server have the plaintext password, instead having a one-way function of the password. The former is called a symmetric password-based protocol, because both the client computer and the server system share the same plaintext password, whereas the latter is called asymmetric.
The lack of an easy-to-use secure authentication mechanism has been a long-standing problem, because users like to use passwords that they can remember and because current single-factor password authentication technology offers little protection when weak and easily-guessed passwords are used (such passwords are considered to be low-entropy passwords). For example, such passwords can be discovered when messages captured during a protocol run are used in a "dictionary attack."
The following United States patents represent password-authenticated key exchange technology: U.S. Pat. No. 5,241,599; U.S. Pat. No. 5,440,635; U.S. Pat. No. 6,226,383; U.S. Pat. No. 6,539,479; and U.S. Pat. App. No. 20050157874. None of these teach or suggest the use of multiple authentication factors in a password-authenticated key exchange protocol where the authentication secrets are not exposed to either party or to the network. They do teach aspects of the technology assumed to be known to one skilled in the art and so U.S. Pat. No. 5,241,599, is hereby incorporated by reference; U.S. Pat. No. 5,440,635 is hereby incorporated by reference; U.S. Pat. No. 6,226,383 is hereby incorporated by reference; U.S. Pat. No. 6,539,479 is hereby incorporated by reference; and U.S. Pat. App. No. 20050157874 is hereby incorporated by reference.
There exist two-factor authentication schemes that do not provide cryptographic protection for the two factors. In a multi-channel system, the short-term password (an authentication factor that the user now has) can be delivered over a separate second channel (for example, via an SMS text message on a mobile phone). Once received, the user can then input the short-term password into their web browser along with their long-term password (an authentication factor that the user knows). In a multi-layer system, the server system evaluates additional attributes such as an HTTP cookie, IP address, and browser user agent string to heuristically analyze whether the user is likely to be authentic.
Some multi-layer systems try to offer additional reassurance to the user of the server's identity by presenting the user with a customized image or string. While these multi-channel and multi-layer approaches can offer some increased assurance, they can be defeated by non-cryptographic means such as sophisticated MITM attacks and spyware, and have been shown to be easily ignored by users.
It would be advantageous to design a multi-factor protocol that can leverage multiple authentication secrets, and that can enable each system to verify that the other system has access to authentication secrets securely in a multi-factor key exchange cryptographic protocol, without exposing the authentication secrets to the network or to the other system.

Multi-factor password-authenticated key exchange


Described herein are fire hoses incorporating new combinations of materials to increase the hose's resilience. Resilient hoses include those made with silicone-coated fabrics or with thermally-resistant fabrics or both.

Firefighters and their equipment are exposed to extreme conditions in the operating environment. These conditions have changed over time due to changes in construction methods and materials. These changes have resulted in increased thermal exposures within a reduced operational timeline, as shown in FIG. 1. As response times have not significantly changed, the available safe operational time for firefighters has been reduced and their equipment is potentially subject to greater thermal exposure. (Ahrens M (2010) Home structure fires. National Fire Protection Association, Quincy; Fahy R F (2010) US fire service fatalities in structure fires, 1977-2009. National Fire Protection Research Foundation, Quincy)
Fire hoses in particular play a critical role in the response and in keeping firefighters safe. In the event that they are damaged or fail firefighter safety is severely threatened. The ability of firehose to withstand thermal exposure from fires has been a subject of study since the March 2014 fire incident in Boston, Mass. that resulted in the death of firefighters Michael R. Kennedy and Edward J. Walsh. A NIOSH study stated:                "Current hoseline standards do not address the thermal performance of attack hoselines, and technical information published by manufacturers does not include thermal performance data . . . Fire service research organizations, standards making organizations, equipment manufacturers, and fire departments should consider the effects of thermal degradation on fire attack hose."            (NIOSH, Death in the Line of Duty Report #F2014-09 (2016). Lieutenant and Fire Fighter Die and 13 Fire Fighters injured in a Wind-driven Fire in a Brownstone—Massachusetts). Recent research by Worchester Polytechnic Institute (WPI) identified 172 burn-through incidents of fire hose as of October 2015. The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) has reported at least one additional incident occurred in February of 2018 during a fire in Missouri. (Thermal Impact of Radiant Heat on Interior Fire Attack Hose, Bureau of Alcohol Tobacco and Firearms Presentation, August 2014).
ATF conducted an experimental study using full-scale and bench-scale experiments to study the response of hoselines to thermal insults. The full-scale tests in the ATF study appeared to emphasize the performance of the hoseline itself, with little attention given to hoseline-coupling interaction, other than what might have been included in the full-scale tests. The full-scale experiments involved routing hoselines through two-story structures and measuring the approximate heat flux and temperature at the time of rupture. Hoselines that were dry and unpressurized, pressurized with water, and pressurized with water flowing through the nozzle were tested. Results indicate that when radiation levels at the floor reached between 14 and 35 kW/m2, the hoselines ruptured. All of the hoselines had failed when the radiant exposure exceeded 40 kW/m2 (Thermal Impact of Radiant Heat on Interior Fire Attack Hose, Bureau of Alcohol Tobacco and Firearms Presentation, August 2014). These exposures were used as the benchmark exposures for the subsequent small-scale tests in which air-charged and water-charged hoselines were tested in the cone calorimeter.
The following table provides a summary of exposure conditions and their consequences, incorporating the test conditions from the ATF study.
TABLE 1Effect of Radiant Heat Flux Exposure (from NFPA 921) with ATFHoseline Thermal Exposure Analysis Values Incorporated. (ThermalImpact of Radiant Heat on Interior Fire Attack Hose, Bureau ofAlcohol Tobacco and Firearms Presentation, August 2014;Guide for Fire and Explosion Investigations (2014) NFPA921, National Fire Protection Association, Quincy)ApproximateRadiant Heat Flux(kW/m2)Comment or Observed Effect1.0Nominal solar constant on a clear summer day.5.0Human skin experiences pain with a 13-secondexposure and blisters in 29 seconds with second-degree burn injury.10.0[Exposed] Human skin experiences pain with a 5-second exposure and blisters in 10 seconds withsecond-degree burn injury.20.0Heat flux on a residential family room floor at thebeginning of flashover.29.0Wood ignites spontaneously after prolongedexposure.30.0"Low" Heat Flux Value used for ATF thermalanalysis of hoselines (based on full scale scopingtest data).40.0"High" Heat Flux Value used for ATF thermalanalysis of hoselines (based on full scale scopingtest data).52.0Fiberboard ignites spontaneously after 5 seconds.~80.0Heat flux for protective clothing Thermal ProtectivePerformance (TPP) test.170.0Maximum heat flux as currently measured in a postflashover fire compartment.
The testing of commercial fire hoses demonstrated the need for fire hose construction that can withstand conditions realistic to a real-world fire scenario. These tests also demonstrated that fire hoses of different compositions fail in different manners. Fire hoses tested were observed to fail in range of different severities from large orifice ruptures to small jetting and pinhole leakage. A weeping type failure was also observed for several tests conducted in which water saturated the exposed section of hose from the inside out while still maintaining the flow path of water. Weeping is believed to occur when the inner liner of the hose begins to fail prior to the outer jacket of the hose jacket, releasing water in a form other than jets or streams.
These studies highlight the need for firehoses with higher thermal resistance that will be more resistant to failure, improving firefighting efficiency, increasing firefighter safety and saving lives.


A similarity memory stores a syllable recognition candidate and its similarity (j) supplied from a syllable recognition section at a specific storage position defined by reference syllable data and its syllable position (i), stores a subsidiary similarity (j-10) at an (i+1)th syllable position of the same syllable name, and stores a subsidiary similarity (j-20) at an (i+2)th syllable position of the same syllable name. The subsidiary similarity (j-10) is also stored at the (i+1)th syllable position of the same syllable name. A coincidence computing section computes a sum of similarities of a series of n syllables from the similarity memory and computes a coincidence.

1. Field of the Invention
The present invention relates to a speech recognition apparatus which can recognize a speech input with high accuracy.
2. Description of the Related Art
A word recognition apparatus which recognizes a word consisting of n syllables or a word consisting of n characters is known, as disclosed in, e.g., Japanese Patent Disclosure (Kokai) No. 59-197974.
The recognition apparatus performs recognition processing of syllables Ai (i=1, 2, . . . , n) of a speech input consisting of n syllables, and obtains similarities (or differences) Sk,i (k and i respectively indicate a syllable name and number) between syllables Ai (i indicates the syllable number) and syllables Bk to be recognized (k=1, 2, . . . , m; k indicates a syllable name). (The syllables to be recognized are all the syllables to be compared with syllables Ai; for example, in Japanese, there are 101 categories as single syllables). The apparatus then stores similarities Sk,i at specific storage positions on a similarity memory defined by syllables Bk to be recognized and their syllable positions i. The similarities stored at positions on the similarity memory defined by syllable codes Ci (i=1, 2, . . . , n) of dictionary words registered in a dictionary memory and syllable positions i of syllable codes Ci in the dictionary words are obtained for syllables of the dictionary words. Thereafter, coincidences between syllables Ai of the speech input and syllables Ci of the dictionary words are computed based on the similarities obtained from the similarity memory, and dictionary words having high coincidences are obtained as recognition candidates of the speech input.
With this speech input recognition method, a speech input can be easily and appropriately recognized at high speed, and can be input as data.
However, as a voiced speech input becomes natural, some of syllables Ai (i=1, 2, . . . , n) of the speech input may be omitted, or one syllable is extracted as a plurality of syllables. For example, if syllable A3 of the speech input is omitted, a recognition series is: EQU A1, A2, A4, A5, . . . , An
If syllable A2 of the speech input is extracted as two syllables A2' and A2", the recognition series is: EQU A1, A2', A2", A4, A5, . . . , An
If such cases occur, an error due to shift in syllable positions after C3 is generated in computations of coincidences for syllable code strings Ci (i=1, 2, 3, . . . , n) of dictionary words, and correct coincidences cannot be obtained. As a result, a speech input cannot be accurately recognized.


A method for producing nano-carbon materials, having a step wherein a starting material comprising one or more kinds of compounds selected from the group consisting saturated hydrocarbons, unsaturated hydrocarbons, saturated cyclic hydrocarbons, and alcohols whose atomic ratio of the component carbon to the component oxygen is more than 2.0 and a catalyst are together treated at a temperature in a range of from 100 to 800° C. while being compressed at a pressure in a range of from 0.2 to 60 MPa.

1. Field of the Invention
The present invention relates to a method for producing nano-carbon materials. More particularly, the present invention relates to a method, which enables one to quantitatively produce nano-carbon materials from a relatively inexpensive starting material in a simple manner using a relatively inexpensive reaction apparatus. The nano-carbon materials produced according to the present invention include carbon nanotubes, carbon nanofibers, and the like.
2. Related Background Art
A fullerene C60 having a soccer ball-like polyhedral molecular structure comprising 60 carbon atoms was discovered by H. W. Kroto, R. E. Smallry and R. F. Curl in 1985. Following the discovery of the fullerene C60, a carbon nanotube (CNT) corresponding to a cylindrical molecule of a fullerene, specifically having a molecular structure in which a graphene sheet (a single atomic layer of crystalline graphite) rolled up into a cylinder, was discovered by lijima in 1991. Since then, other carbon nanotubes have been discovered, and various studies on their industrial application have been carried out.
It has also been reported that these carbon nanotubes have an excellent field emission performance, a function to take up and store lithium therein and release said lithium in the electrochemical reaction, a large specific surface area and a good conductivity. In view of this, researches have been conducted regarding the use of these carbon nanotubes as electrode materials in FEDs (field emission displays), as electrode materials in rechargeable lithium batteries, as catalyst-retaining materials in fuel cells in which polymer solid electrolytes are used, and as hydrogen storage materials in hydrogen storage systems.
As the method for producing such carbon nanotubes, there are known a method wherein arc-discharge is generated in an gas atmosphere containing a carbon material such as hydrocarbon, a method wherein a target comprising graphite is evaporated by irradiating a laser thereto, and a method wherein a gaseous carbon material comprising acetylene or the like is subjected to thermal decomposition on a substrate having a catalyst of cobalt metal or nickel metal arranged thereon.
Particularly, Japanese Laid-open Patent Publication 6(1994) -157016 (hereinafter referred to as "Patent Document 1") discloses a method for producing carbon nanotubes, wherein arc-discharge is generated between a pair of carbon rods respectively as a positive electrode and a negative electrode in an inert gas atmosphere to deposit a carbon nanotubes-containing solid material on the negative electrode.
Japanese Laid-open Patent Publication P2000-95509A (hereinafter referred to as "Patent Document 2") discloses a method for producing carbon nanotubes, wherein a rod-shaped positive electrode containing carbon and non-magnetic transition metal and a rod-shaped negative electrode comprising graphite are arranged such that their tips are opposed to each other and arc-discharge is generated between the tip of the positive electrode and that of the negative electrode in an inert gas atmosphere to deposit carbon nanotubes on the tip portion of the negative electrode.
Japanese Laid-open Patent Publication 9(1997) -188509 (hereinafter referred to as "Patent Document 3") discloses a method for producing carbon nanotubes, wherein a carbon material and a metal catalyst are supplied into a high frequency plasma generated to deposit carbon nanotubes on a substrate.
Japanese Laid-open Patent Publication 10(1998) -273308 (hereinafter referred to as "Patent Document 4") discloses a method for producing carbon nanotubes, wherein a graphite-containing carbon rod is positioned in a quartz tube arranged in an electric furnace and laser light is irradiated onto the carbon rod in an inert gas atmosphere to deposit carbon nanotubes on the inner wall face of the quartz tube.
Japanese Laid-open Patent Publication P2000-86217A (hereinafter referred to as "Patent Document 5") discloses a method for producing carbon nanotubes, wherein gaseous hydrocarbon is thermally decomposed on a catalyst comprising a molybdenum metal or a molybdenum metal-containing material to deposit carbon nanotubes on said catalyst.
Separately, Carbon Vol. 36, No. 7-8, pp. 937-942, 1998 (Yury G. Gogotsi et al.) [hereinafter referred to as "Non-patent Document 1"] describes a method wherein filamentous carbons are formed from paraformaldehyde by way of hydrothermal reaction at a temperature of 700 to 750° C. under 100 MPa pressure for 150 hours.
Journal of Materials Research Society, Vol. 15, No. 12, pp. 2591-2594, 2000 (Yury Gogotsi et al.) [hereinafter referred to as "Non-patent Document 2"] describes a method wherein multi-wall carbon nanotubes are formed from polyethylene by way of pyrolysis of said polyethylene in the presence of nickel at a temperature of 700 to 800° C. under 100 MPa.
Journal of American Chemical Society Vol. 123, No. 4, pp. 741-742, 2001 (Jose Maria Calderon et al.) [hereinafter referred to as "Non-patent Document 3"] describes a method wherein multi-wall carbon nanotubes are formed from amorphous carbon through a hydrothermal treatment of the amorphous carbon in the absence of a metal catalyst at a temperature of 800° C. under 100 MPa pressure for 48 hours.
However, the methods disclosed in patent Documents 1 to 5 have disadvantages such that the starting material and the apparatus used for practicing the method are costly and therefore a product obtained becomes unavoidably costly and it is difficult to quantitatively produce nano-carbon materials.
Similarly, the methods described in Non-patent Documents 1 to 3 have disadvantages in that because high pressure of 100 MPa is used, a specific high pressure capsule made of Au (which is costly) and which can withstand such high pressure is employed as the reaction vessel, and the starting material and water are introduced into the capsule, wherein the starting material is subjected to a hydrothermal reaction at a high temperature (700 to 800° C.) under a high 100 MPa pressure. Therefore, a product obtained by any of these methods unavoidably becomes costly. Non-patent Documents 1 to 3 do not even suggest a method in which nano-carbon materials (including carbon nanotubes or filamentous carbons) can be formed under low pressure condition of less than 60 MPa, using a relatively inexpensive pressure reaction vessel without the necessity of using an expensive pressure reaction vessel.
There is a demand for providing a method capable of quantitatively producing nano-carbon materials (including carbon nanotubes and carbon nanofibers) at a reasonable production cost from relatively inexpensive raw material in a simple manner under low pressure, which does not require the use of a specific and costly pressure reaction vessel as described above.
Separately, Carbon Vol. 40, pp. 2961-2973, 2002 (Mingwang Shao et al.) [hereinafter referred to as "Non-patent Document 4"] describes a method wherein carbon nanotubes having a multi-layered structure are formed by reacting benzene as a starting material with a nickel-iron powder as a catalyst at a temperature of 480° C. under a reaction pressure of about 15 Pa pressure for 12 hours in a stainless steel autoclave. Although this method is advantageous in that the reaction pressure upon forming a nano-carbon material (a carbon nanotube having a multi-layered structure) is low (about 15 Pa), the method has a disadvantage in that the amount of a nano-carbon material produced in the reaction after a relatively long time (12 hours) is small. In particular, a ratio of the weight of the nano-carbon material produced to the weight of the catalyst used is 4.2, which is small. In addition, according to the results of the measured Raman spectrum of the obtained nano-carbon material, which results are described in Non-patent Document 4, it is understood that for the relative intensity between the so-called G-band peak near 1590 cm−1 due to a lattice vibration in the hexagonal lattice network of the carbon atoms and the so-called D-band peak near 1350 cm−1 due to a lattice defect of the carbon atoms, the intensity of the peak near 1350 cm−1 is stronger. This means that the nano-carbon material obtained by the method described in Non-patent Document 4 is accompanied by a number of lattice defects. Thus, although the method described in Non-patent Document 4 has an advantage in that the reaction pressure upon forming a nano-carbon material is low, it is difficult to stably produce a nano-carbon material with only a slight lattice defect. It is desirable to improve the method described in Non-patent Document 4 so that it can stably produce a high-quality nano-carbon material with few lattice defects in a shortened reaction time.
In addition, such nano-carbon materials as described above are expected to be widely used in various technical fields, for instance, as electrode materials in FEDs (field emission displays), as electrode materials in rechargeable lithium batteries, and as catalyst-retaining materials in fuel cells. In view of this, there is a demand for a technique, which can enable one to efficiently produce high-quality nano-carbon materials at a reasonable production cost.

Method for producing nano-carbon materials


A ski tow fixture for removably securing a ski tow rope to a boat hull includes a generally elongate base unit supporting two bent portions having a generally common axis of bending and being generally sidewardly spaced along the common axis and generally sidewardly aligned. The bent portions are spaced from an end of the elongate base unit. Each bent portion extends from the base unit to a free end near the above-mentioned end of the base unit.

Many conventional quick release ski tow fixtures include some form of a planar loop structure and a cross bar member. The cross bar member is usually disposed to extend generally across the planar loop, one end of the cross bar member being fixed to the loop or closely adjacent thereto so as to be substantially in the plane of the loop. The cross bar member extends from this fixed end in a direction generally inclined relative to the plane of the loop to a free end spaced from the plane of the loop. U.S. Pat. No. 2,962,998 granted to Long on Dec. 6, 1960, and U.S. Pat. No. 3,890,918 granted to Sell on June 24, 1975, disclose examples. Because of the cross bar structure, the ski tow fixture disclosed in these patents cannot be conveniently produced from a unitary piece of metal stock. Welding or other fastening arrangements are generally required for the cross bar member. Thus, unwanted manufacturing expenses and potential failure of the fastening arrangement are disadvantages of such ski tow fixtures.
Moreover, ski tow fixtures of that kind, which are mounted on a boat so that the cross bar is generally upstanding, are potential safety hazards. More specifically, a person who slips on a wet deck or the like and falls on the ski tow fixture could incur a puncture wound from the free end of the upstanding cross bar member.
U.S. Pat. No. 4,738,216 granted to Camarota et al. on Apr. 19, 1988 and assigned to the assignee of the present invention discloses a planar loop and cross bar structure wherein the cross bar member extends generally in the plane of the loop, and bends out of the plane of the loop only near its free end, with the free end located to avoid the safety hazard above stated (FIGS. 2 and 5-6). However, like the loop and angled cross bar structure above mentioned, this prior Camarota ski tow fixture also cannot be conveniently formed from a unitary piece of metal stock.
Accordingly, it is an object of the present invention to provide a tow apparatus for removably securing a tow rope to a boat hull and which can be formed from a unitary piece of metal stock.
It is a further object of the present invention to provide a ski tow apparatus, as aforesaid, which is simple and inexpensive to manufacture, assemble and attach to a boat hull.
It is a further object of the present invention to provide a ski tow apparatus, as aforesaid, which is adapted for quick, easy and secure attachment of a ski rope loop thereto.
It is a further object of the present invention to provide a ski tow apparatus, as aforesaid, having a generally safe construction.


A system and method for electromagnetically arresting an aircraft landing on an undersized runway, as on an aircraft carrier. The system preferably comprises a cross-deck pendant cable coupled to two purchase cables that are wound around low inertia purchase cable spools on opposite ends. The shafts of the purchase cable spools are mechanically coupled to one or more low inertia induction machines used to arrest the landing aircraft. As the aircraft contacts the cross-deck pendant cable and extends the purchase cables down the runway, power electronics in the system apply a torque based on closed-loop feedback to the induction machine acting as a generator, and the mechanical energy of the aircraft is converted to electrical energy at the generator and is dissipated as heat in an attached resistor. The one or more induction machines are preferably cup-type generators, and the generators may be briefly run as motors to initially reduce the tension on the purchase cables.

1. Field of the Invention
The present invention relates generally to an electromagnetic-based arresting system for use onboard an aircraft carrier to catch and stop an incoming aircraft, and, more particularly, the present invention utilizes a low inertia induction motor/generator which allows the rapid acceleration of the spool, generator and arresting cable to match the landing speed of the aircraft before applying braking torque to ultimately stop the aircraft.
2. Description of the Background
For various remote and local applications, it is desired to land aircraft on a runway that is too short for a conventional landing, such as on an aircraft carrier or other naval vessel. Traditionally, in order to catch and stop (collectively xe2x80x9carrestxe2x80x9d) aircraft on a moving ship or other short runway, a cross-deck pendant cable is placed horizontally across the landing path of the incoming aircraft. A hook or other xe2x80x9ccatchingxe2x80x9d implement hanging below the belly of the aircraft engages the horizontal cable, and the resistance of the cable is then increased as the cable is run-out down the runway until the forward movement of the aircraft is halted. Because the aircraft is typically moving at a high rate of speed, there is a high level of stress on both the aircraft and the arrestor system cable upon impact. Therefore, the cable must be allowed to run-out to approach the speed of the landing plane or utilize some other tension reduction technique in order to reduce this stress on both the aircraft and the arrestor system.
Conventional aircraft arrestor systems, such as the Mark 7 (MK7) arresting gear presently used on the CVN 68 class of aircraft carriers, utilize a hydraulic ram/fluid system to partially compensate for the speed of the landing aircraft. Specifically, the cross-deck pendant cable is connected to two purchase cables that are ultimately wound around two wire spools with enough cable to run-out the length of the landing surface. Each length of purchase cable is run through a series of sheaves and sheave dampers in order to progressively impart a resistance on the purchase cable as it is run-out down the runway. Basically, as the landing aircraft imparts tension on the purchase cables, a ram is pulled through a viscous fluid to impart this progressive resistance to both absorb the initial shock of the aircraft and to eventually stop the aircraft""s forward momentum. As the incoming aircraft xe2x80x9chooksxe2x80x9d the cross-deck pendant and runs out the purchase cables, the sheaves and sheave dampers work to slow the aircraft.
This particular prior art system is manpower intensive for both day-to-day operation as well as in terms of maintenance. Specifically, a typical arresting gear system (there are four sets of cables on an average aircraft carrier) requires approximately 18 operators per ship. Further, key components of the system have limited service life, requiring frequent replacement, because of the large stresses imparted on the system during each landing. The amount of required maintenance is intensified because of the open-loop feedback structure of the MK7. In essence, after pre-setting certain valves based on the type and speed of the landing aircraft, there is no additional feedback or adjustment made to the purchase cable tension. Especially in off-center arrests (i.e., the plane does not impact the cross-deck pendant in the center thereby causing an unequal load distribution on each purchase cable), the actual amount of tension imparted on each purchase cable is not accurately controlled.
Moreover, the hydraulic fluid itself used in the sheave-damper system is not preferred. Specifically, this fluid is often classified as a hazardous fluid. Such fluids may leak, especially through wear, and could cause a loss of operation time for maintenance or even injury.
A second, and much more complicated prior system utilizes a mechanical means to couple the purchase cable spool to a motor/generator that is already spinning. By coupling the cable to the spinning motor/generator, the tension on the cable may be increased, and the aircraft will eventually be brought to a stop. Because of the highly complicated forces at work when coupling a running motor/generator to a running cable system, this system is expensive, less reliable, and frequently prone to error or mechanical failure.
Neither of the existing prior art systems provides a reliable aircraft arrestor system with the ability to be operated with a minimal number of personnel. Further, each of these systems are limited in the size and speed of landing aircraft that can be arrested. The present invention preferably provides better reliability through redundant control systems, reduced manning (e.g., 4-9 operators/ship) through automation, and reduced maintenance. As such, the present invention, in at least one preferred embodiment, addresses one or more of the above-described and other limitations to prior art systems.
In accordance with at least one preferred embodiment, the present invention provides an electromagnetic aircraft arrestor system utilizing a low inertia, low torque induction machine (i.e., motor/generator) to apply a progressive and controlled tension to the purchase cables during cable run-out. The basic elements of the present arrestor system may be designed to interface directly with existing sheave-damper systems currently employed with prior art hydraulic arrestor systems. One of two purchase cables are connected to each end of a cross-deck pendant which is engaged by a landing aircraft. The opposite ends of these purchase cables are preferably wound on spools coupled to the shaft of a low inertia induction machine which provides braking torque to the spool that is translated into braking tension in the cables.
As the landing aircraft moves down the runway, its mechanical energy is translated through the running purchase cables to impart rotational energy on the one or more induction machines (now running as generators) connected to the purchase cable spools. The generated electrical energy is then dissipated through the use of a braking resistor. By monitoring the rotational movement of the induction machines during cable run-out in a closed-loop feedback orientation, the proper amount of torque can be applied to the induction machine to properly slow the landing aircraft without imparting a tension in the purchase cable that exceeds the mechanical limits of the cable.
The present arrestor system may utilize a single or dual induction machine orientation to stop a landing aircraft. In a single induction machine system, both purchase cable spools are connected to the shaft of the induction machine. In the preferred system utilizing two separate induction machines, each purchase cable spool is connected to a separate machine. With this orientation, off-center aircraft arrests may be more properly controlled, as unequal torque profiles may be used on the two induction machines to account for the difference in the stresses imparted on the two purchase cables by the aircraft landing off-center.
The induction machines of the present invention may be passive and allow for the run-out of the spooled purchase cables through low torque and low inertia. However, to aid in the initial purchase cable run-out, the one or more induction machines may also optionally be capable of operating as a motor for brief periods of times. Therefore, upon initial contact between the landing aircraft and the cross-deck pendant, the induction machine(s) may unwind a specified amount of spooled cable to reduce the initial tension in the purchase cables. After a short period of time, the induction machine will return to generator mode and, through the conversion of mechanical energy to heat in a resistor, will stop the landing aircraft according to a predefined profile and closed-loop feedback.

Electromagnetic aircraft arrestor system


A DC-DC converter includes a bridge circuit, a resonant tank circuit coupled to an output of the bridge circuit; a rectifier circuit having an input coupled to the resonant tank circuit and an output, and an output filter coupled to the output of the rectifier circuit. A controller is coupled to the bridge circuit, the resonant tank circuit and the output of the DC-DC converter. The controller is configured to control a switching frequency of the bridge circuit to operate the DC-DC converter as a boost converter and a buck converter. When the DC-DC converter is operating as a buck converter, the controller controls the rectifier circuit to selectively block energy transfer from the rectifier circuit to the converter output based upon an output current of the DC-DC converter being greater than current demand thereof, thereby reducing output current of the DC-DC converter and extending an operating range thereof.

DC-DC converters, which convert an input DC voltage to an output DC voltage, have application in, for example, electric vehicles as part of battery charging system in which the converter is powered by large high voltage batteries that require recharge from the grid. For personal safety from electric shock hazards, galvanic isolation from the grid to the high voltage battery is required. This galvanic isolation requirement is fulfilled by magnetically coupled coils. To transfer energy in this magnetic circuit, a DC source is excited by a transistor bridge circuit. The DC source is provided by a power factor correction (PFC) circuit that converts the AC grid voltage to a 400 V DC source. Grid voltage limits this DC source to a worst case voltage of 375 V.
The electric battery voltage range can be anywhere from 200 V to 500 V depending on the series and parallel combination of the individual battery cells. The battery charging system is typically required to provide a constant DC current to the battery stack. A separate battery controller monitors the battery voltage and the individual cell temperatures and commands a charging current that is appropriate for a specific battery state of charge.
One limitation for some resonant converter topologies is voltage range, especially at low load conditions. For some battery charging systems, this limitation is mitigated by the turns ratio and inductance ratio design parameters. Broadly speaking, the transformer turns ratio sets the approximate minimum voltage capability while the ratio between the magnetizing inductance and series resonant inductance determines the gain of the tank circuit for maximum battery voltage charging. For a primary to secondary coil turns ratio of 2:1, the 400 V DC link source may operate down to the certain battery state of charge and maintain zero voltage switching (ZVS) in the bridge transistors even for a relatively low current. This is because the primary side current at this operating point is dominated by the magnetizing current. Magnetizing current is intentionally high from the low magnetizing inductance used to set the tank gain. However, as the switching frequency increases above the resonant frequency of the tank circuit, the peak magnetizing current is reduced and ZVS is lost. This is the buck region of operation, and the resonant tank transfer function also becomes flat requiring switching frequencies higher than bridge transistor capability. FIG. 1 illustrates a normalized transfer function of the resonant tank circuit as a function of switching frequency, showing both the boost and buck regions of operation. Below the resonant frequency, the DC-DC converter operates in the boost region or mode where the resonant tank circuit operates in a discontinuous conduction mode (DCM) and ZVS is maintained so long as the energy in the resonant tank is not depleted. It is desirable to reduce this boost range because the energy lost in the power transfer increases as switching frequency decreases. Furthermore, the hold-up time on the capacitor of the resonant tank circuit eventually becomes a limitation because ZVS is lost and also the transfer function becomes nonmonotonic. This low switching frequency point of operation sets the maximum charge voltage capability. If a decision is made to reduce the minimum battery voltage or current required by the battery charging system beyond the operating range of the resonant tank circuit, the resonant tank circuit may need to be redesigned. And this range increase may only be needed to support the rare condition that the battery is in a deeply depleted state of charge.

DC-DC converter with extended light load operating range, and method of using same


A detection substrate and a manufacturing method thereof, and a detector are provided. The detection substrate comprises a base substrate, a thin film transistor, a PIN photodiode and a scintillation layer. The thin film transistor and the PIN photodiode are provided above a first face of the base substrate and the scintillation layer is provided above a second face of the base substrate. The visible light obtained after the X-ray passes through the scintillation layer is directly irradiated on the PIN photodiode after passing through the base substrate with relative high transmittance, thus preventing intensity of the light irradiated on the PIN photodiode from being weakened, and improving light utilization efficiency of the detection substrate.

FIG. 1 is a structural diagram of a detection substrate in the prior art. As shown in FIG. 1, the detection substrate comprises a base substrate 101 onto which a thin film transistor is provided, and the thin film transistor comprises a gate 104, a gate insulation layer 105, an active layer 106, a source 107 and a drain 108. A PIN photodiode 102 is provided above the source 107 and the drain 108. A passivation layer 109 is provided above the source 107, the drain 108 and the PIN photodiode 102. A metal layer 201 is provided above the active layer 106. The metal layer 201 is arranged to shield light irradiated towards the active layer 106. A resin encapsulation layer 202 is provided above the passivation layer 109 and the metal layer 201. A scintillation layer 103 is provided above the resin encapsulation layer 202.
Absorption efficiency of the detection substrate to visible light is decided by the PIN photodiode 102, therefore, the PIN photodiode 102 can influence a plurality of critical indexes of the detection substrate, e.g. dose of X-ray, resolution of X-ray imaging, response speed of an image. However, in an existing detection substrate, the scintillation layer 103 is provided above the thin film transistor and the PIN photodiode 102, the visible light obtained after the X-ray passes through the scintillation layer 103 is irradiated on the PIN photodiode 102 after passing through the resin encapsulation layer 202 with low transmittance, thus making intensity of the light irradiated on the PIN photodiode 102 being weakened, and reducing light utilization efficiency of the detection substrate.

Detection substrate and manufacturing method thereof, and detector


Methods are provided herein for identifying whether a cancer patient, for example a colorectal cancer patient, will be responsive to treatment with a therapeutic strategy comprising administration of the FOLFOX regimen (5-fluorouracil, leucovorin, and oxaliplatin). Specified TYMP and UCK2 fragment peptides are precisely detected and quantitated by SRM-mass spectrometry directly in tumor cells, for example colorectal cancer tumor cells, that are collected from tumor tissue obtained from a cancer patient and compared to reference levels in order to determine if the cancer patients will positively respond to treatment with the combination treatment of FOLFOX (5-fluorouracil, leucovorin, and oxaliplatin).

Fluorouracil (5-FU), also known as adrucil, is a chemotherapy agent that functions by blocking the production of DNA, which inhibits cell division and thereby prevents tumor cells from dividing and growing. 5-FU acts in several ways, but principally as a thymidylate synthase (TS) inhibitor. Interrupting the action of this enzyme blocks synthesis of the pyrimidine thymidine, which is a nucleoside required for DNA replication. TS methylates deoxyuridine monophosphate (dUMP) to form thymidine monophosphate (dTMP). Administration of 5-FU causes a scarcity in dTM. Thus, rapidly dividing cancerous cells undergo cell death due to lack of thymine. High levels of TS can overcome the effects of 5-FU while high levels of the TYMP protein promotes the activity of 5-FU.
Leucovorin calcium (LV), also known as folinic acid, potentiates the growth inhibitory effects of 5-FU. LV is a precursor for 5,10-methylene-tetrahydrofolate (CH2-THF) and CH2-THF enhances the inhibition of TS by the 5-FU metabolite FdUMP.
Oxaliplatin, also known as eloxatin, is a cancer chemotherapy agent that interferes with DNA replication, thus preventing cells from dividing and leading to tumor cell death via apoptosis. Oxaliplatin is thought to form platinum-DNA adducts in tumor cell DNA, that appear to be more effective at blocking DNA replication and are more cytotoxic than adducts formed from cisplatin. The damaged DNA elicits DNA repair mechanisms, which in turn activate apoptosis when repair proves impossible thus killing the tumor cells.


A method for use in a terminal device is provided. The method includes: detecting a trigger signal generated from a multilevel progress bar, wherein the multilevel progress bar includes a first progress bar with a first progress slider and a second progress bar with a second progress slider; when the trigger signal is detected from the first progress bar, calculating a first sliding distance of the first progress slider according to a sliding trajectory indicated in the trigger signal; calculating a progress-adjusting value according to the first sliding distance and a first progress-adjusting function of the first progress bar; calculating a second sliding distance of the second progress slider of the second progress bar according to the calculated progress-adjusting value and a second progress-adjusting function of the second progress bar; and controlling sliding of the progress slider of the second progress bar according to the second sliding distance.

With the development of portable terminal devices, such as smart phones, users often use portable terminal devices to browse webpages or watch videos. When a user is browsing a webpage or watching a video, the user may play fast-forward or play backward the webpage or the video as desired.
Conventionally, in many applications, in order to allow a user to control a play progress, a horizontal or vertical progress bar may be provided on a user interface page. The progress bar indicates, e.g., the play progress of a webpage or a video. There may be a button on the progress bar, and a position of the button on the progress bar may indicate the progress of the program. By pressing and dragging the button, or by tapping a position of the progress bar to move the button to that position, the user may control the play progress of the webpage or the video.


An uncured composite product having a middle fibrous reinforcement, a thermosetting-resin based layer and a hardening-agent based layer for the thermosetting resin. The thermosetting-resin based layer is placed on one side of the fibrous reinforcement and the hardening-agent based layer is placed on the other side so that the fibrous reinforcement forms a physical barrier between the thermosetting resin and the hardener. When heated, the thermosetting resin and/or hardener flows across the physical barrier to provide mixing and resultant curing.

1. Field of the Invention
The present invention concerns the technical area of composite products, more particularly, products used for the fabrication of molded articles or parts.
2. Description of Related Art
Composite molded articles are light and at the same time strong. They are used in a wide variety of applications, including: aeronautical construction, for example for the design of airplane wings; aerospace and naval construction, for example for the fabrication of ship masts or hulls; automobile manufacturing; the mechanical electrical industries; and the fabrication of sports articles such as skis, tennis rackets and sail boards.
One of the fabrication techniques for molded articles involves using prepregs formed of an impregnated fibrous reinforcement, generally a resin that associates a thermosetting polymer and a cross-linking agent, also called a hardening agent, and possibly additives that serve to improve the performance of the molded article obtained.
The prepregs are laid up in a mold so as to obtain the desired shape and linked to each other by cross-linking the thermosetting polymer.
However, the prepregs are difficult to store at room temperature. Indeed, the fact that fibrous reinforcement is impregnated with a homogenous mixture of thermosetting polymer and its cross-linking agent at room temperature leads to a cross-linking reaction, slow, to be sure, of the thermosetting resin.
Thus, a major inconvenience associated with the use of such prepregs is that they require cold storage to minimize the change in the resin during storage. In addition, cross-link reaction control processes are often necessary when prepregs are used in designing molded parts. The consequence of the change in the resin is that the prepregs must be used rather quickly or they become unusable. Solutions that provide composite products in which the resin matrix has good storage qualities at room temperature have therefore been sought.
U.S. Pat. No. 3,666,615 describes the combination of a layer of thermosetting resin and a layer of hardener in which the two layers are separated by a film that prevents any contact between the resin and the hardener. The film is made of a material that melts when heated. Thus, raising the temperature eliminates the physical barrier made by the film and establishes contact between the thermosetting resin layer and the hardener layer which can then react. A fibrous base is included in the thermosetting resin layer or in the hardener layer and fills the function of a strengthener. Nevertheless, this technique requires using a film of a different type from the thermosetting resin, which complicates the system.
The application for a European patent published under number EP 1 072 634 uses adjacent layers of reactive materials, but in this case, there is no physical barrier separating the resin and the cross-linking agent. Therefore, the cross-linking reaction may take place at the interface of the layers during storage.
It appears then that the preceding techniques are not entirely satisfactory. In that context, there is a need for composite products comprising first, a reinforcement structure and second, a system combining a thermosetting resin that can undergo a cross-linking reaction. This product should provide satisfactory stability at room temperature, thus facilitating storage.

Composite products and molded articles obtained from said products


This invention relates to a dust indicator in a vacuum cleaner, which dust indicator (200) is arranged in a wall (102) at least partly defining a space of the vacuum cleaner that is set under negative pressure with respect to the outside of the wall during operation of the vacuum cleaner. The dust indicator comprises an air channel (211) having an air inlet (212) arranged at an outer side of the wall, and an air outlet (213) arranged at an inner side of the wall, such that an airflow is directed into the space during operation of the vacuum cleaner due to the negative pressure. The dust indicator further comprises a sensor (220) arranged for detecting dust by means of sending and/or receiving an electromagnetic signal which is transmitted through the space. The air channel is arranged such that the airflow prevents dust from sticking in an area of the path of the electromagnetic signal of the sensor. The sensor is arranged behind a transparent window (232) such that it is shielded from dust and debris within said space.

Recently, the use of bag less vacuum cleaners, that is vacuum cleaners which do not make use of disposable dust bags, has increased. Dust from the dust laden airstream which is sucked into the vacuum cleaner is separated in a dust separation chamber and collected in a dustbin, which must be frequently emptied by the user. As long as the dust level in the dustbin is below a critical level, normal functionality of the dust separation in the vacuum cleaner is provided. However, a common problem for bag less vacuum cleaners is that the user forgets to empty the dustbin before the critical level is reached, which results in unnecessary clogging of filters and other parts of the vacuum cleaner. The consequences of this are loss of cleaning performance and increased amount of maintenance of e.g. the main filter and filter screen. Thus, there is a need for indicating to the user when it is time to empty the dustbin before the critical level is reached.
It is known to arrange optical dust indicators in vacuum cleaners for the purpose of detecting dust. The optical dust indicators are typically based on optical sensors providing a detections system, such as a light emitter in combination with a light receiver, which are arranged such that when dust is present in the optical path of the optical signal provided by the light emitter, the light detector detects a decreased or blocked light signal. The optical dust indicators are sensitive to dust getting stuck somewhere in the optical path of the detection system, as this blocks the light signal.
A dust detector utilized in a vacuum cleaner to indicate the amount of dust in a dust laden air stream is disclosed in U.S. Pat. No. 5,163,202. The dust detector is arranged in a suction passage in fluid contact with e.g. a floor nozzle of the vacuum cleaner. A light-emitting element and a light-detecting element, are arranged in a respective opening. The openings are diametrically oppositely arranged in the suction passage wall. The light-emitting element and the light-detecting element are arranged in optical communication and dust is detected when being present in the optical path of the detection system. Further, air passages guarded by pressure responsive valves are defined in the suction passage wall. These are arranged for introducing ambient air into the suction passage via the openings during operation of the vacuum cleaner. The pressure difference created between the ambient space and the suction passage during operation of the vacuum cleaner activates the valves and ambient air flushes over the light-emitting element and the light-detecting element, thereby keeping them free from dust-particles which may otherwise contaminate them. The known dust detector is quite complicated as it comprises a plurality of mechanically complex, moving constituents.
Thus, there is a need within the art for an optical dust indicator for indicating the dust level in a dustbin. In particular, it would be advantageous to have an optical dust indicator which constitutes only fixed parts and which prevents from contamination caused by dust-particles in areas overlapping its optical path.