Semiconductor integrated test structures are designed for electron beam inspection of semiconductor wafers. The test structures include pattern features that are formed in designated test regions of the wafer concurrently with pattern features of integrated circuits formed on the wafer. The test structures include conductive structures that are designed to enable differential charging between defective and non-defective features (or defective and non-defection portions of a given feature) to facilitate voltage contrast defect detection of CMOS devices, for example, using a single, low energy electron beam scan, notwithstanding the existence of p/n junctions in the wafer substrate or other elements/features.

Due to continuing technological innovations in the field of semiconductor fabrication, integrated circuit chips are being developed with larger scale of integration and higher device density, as well as lower power consumption and higher operating speeds. In general, integrated circuits are manufactured using FEOL (front-end-of-line) processing technologies to form discrete semiconductor devices within the surface of a silicon wafer followed by BEOL (back-end-of-line) processing techniques to form a multi-level metallurgical interconnection network over the semiconductor devices to provide the wiring and contacts between the semiconductor devices to create the desired circuits. When semiconductor integrated circuits are designed based on sub-micron dimensions and beyond, it is very important that tight dimensional control is achieved since slight variations in processing conditions can generate significant dimensional deviations of the patterned features or other electrical defects. In this regard, semiconductor wafers are typically inspected at various stages/levels of development to ensure quality control and detect and eliminate critical, yield-limiting defects.
For example, electron beam inspection is a common technique that is employed using an SEM (scanning electron microscope) to detect electrical and physical defects on a semiconductor wafer through voltage contrast inspection of a secondary electron image. In general, electron beam voltage contrast inspection involves scanning a target region of the wafer with a focused electron beam emitted by an SEM. The electron beam irradiates the target region causing the emission of secondary electrons and a secondary electron detector measures the intensity of the secondary electron emission along the scan path of the electron beam. As a region is scanned, electrons from the electron beam induce surface voltages that vary over the scanned region due to differential charge accumulation of the irradiated features. Voltage contrast inspection operates on the principle that differences in the induced surface voltages over a scanned region will cause differences in secondary electron emission intensities.
In general, for a given feature, the intensity of secondary electron emission will vary depending on, e.g., the landing energy of the beam electrons (primary electrons) and material composition of the feature. For a given material, a secondary electron yield δ is a measure of a ratio of secondary electron emission to impinging primary electrons as a function of landing energy (eV), i.e.,
  δ  =                    Secondary                                                  Electrons                                                  Emitted                    Electrons                                                  In              .  Different materials irradiated by an electron beams tuned to a specific landing energy will emit different intensities of secondary electrons. The different features within the scanned target region will be displayed in an SEM image with different grayscale shades depending on the intensity of secondary electron emission. The irradiated features having a higher intensity of secondary electron emission may be displayed brighter in an SEM image than those irradiated features having a lower intensity of secondary electron emission.
One common application of e-beam inspection is to perform in-line voltage contrast inspection of conductive features such as interconnects and through-vias to detect electrical defects such as electrical shorts, electrical opens, or resistive shorts/opens, etc. For conductive features, electrical defects can be detected as voltage contrast defects due to charging differences between defective structures and non-defective structures. For instance, FIG. 1 schematically illustrates a conventional electron beam inspection process for voltage contrast inspection of metallic contacts/vias features of a CMOS integrated circuit. In particular, FIG. 1 schematically illustrates a conventional voltage contrast inspection process to detect electrical defects for through-via contacts in a target region (10) of a semiconductor wafer substrate having a first active region (11) and a second active region (12) of a CMOS integrated circuit. The first active region (11) may be a PMOS region comprising an n-well region (11a) and a p+ diffusion region (11b), and the second active region (12) may be an NMOS region comprising a p-well region (12a) and an n+ diffusion region (12b).
A plurality of contacts (13) and (14) are formed on the p+ diffusion region (11b) in the first region (11) and a plurality of contacts (15) and (16) are formed on the n+ diffusion region (12b) in the second region (12). The contacts (13˜16) are formed in an insulating layer (not shown). The contacts (13) and (14) may be metal contacts (e.g., tungsten plugs) that are formed as part of a CMOS integrated circuit to connect the p+ diffusion region (11b) (source/drain) of a PMOS transistor to first level metallization. Similarly, the contacts (15) and (16) may be metal contacts (e.g., tungsten plugs) that are formed to connect the n+ diffusion region (12b) (source/drain) of an NMOS transistor to first level metallization. In the illustrative embodiment of FIG. 1, the contacts (14) and (16) are depicted as defective structures having electrical open defects (14a) and (16a), respectively, while the contacts (13) and (15) are depicted as non-defective structures. The electrical open defects can be readily detected using e-beam inspection due to the sharp voltage contrast differences that would result from differential charging between the defective and non-defective contacts.
In particular, during an electron beam inspection, the semiconductor wafer would be electrically connected to SEM ground (G) or some reference voltage source to control charge build up on the scanned region due to electron beam irradiation. When irradiated by the electron beam, charge accumulation on non-defective contacts (13), (15) would be discharged to SEM ground G through the wafer substrate while charge accumulation on the defective contacts (14), (16) would not foe discharged to SEM ground G due to the open defects (14a), (16a), resulting in differential charge accumulation and thus, different intensities of secondary electron emission. When examined with an SEM in secondary electron emission mode, the differentially charged non-defective contacts (13), (15) and defective contacts (14), (16) would appear in the SEM image with different intensities.
In the conventional embodiment of FIG. 1, two electron beam scans are required to adequately detect voltage contrast defects of contacts in the first and second regions (11) and (12) due to the presence of semiconductor p/n junctions (11b/11a) and (12a/12b) of the respective first and second active regions (11) and (12). For a given scan, the charge accumulation on the contacts (13˜16) may be either positive or negative, depending on the secondary electron yield  of the material forming the contacts (13˜16). In this regard, for a given scan, the p/n junction of one of the first or second regions (11) and (12) can be reversed biased, thereby preventing charge build up on contacts within the given region (11) or (12) from being discharged to SEM ground G. Consequently, there would be very little or no charge differential between defective and non-defective contacts and, thus, no discernable contrast differences in an SEM image between defective and non-defective contacts in the given region.
By way of specific example, assume for illustrative purposes that the contacts (13-16) are formed of tungsten. FIG. 8 illustrates an electron yield curve for tungsten. FIG. 8 generally illustrates that the secondary electron yield δ for tungsten is greater than 1 for a range R_1 of low landing energies and less than 1 for a range R_2 of high landing energies. In this regard, electrically isolated tungsten contacts would be positively charged when irradiated with a low landing energy electron beam, while electrically isolated tungsten contacts would be negatively charged when irradiated with a high landing energy electron beam. FIG. 1 illustrates a voltage contrast inspection process to inspect the contacts (13) and (14) in the first region (11) using a low landing energy electron beam to irradiate the target region (10). The beam electrons (indicated by solid arrows) impinging on the top surface of the contacts (13, 14, 15, 16) would cause a positive charge to accumulate in the contacts (13, 14, 15, and 16).
In the first region (11), positive charge accumulation in the non-defective contact (13) causes the p/n junction (11b/11a) to be forward biased, which allows the positive charge to be discharged to the substrate ground G through the first substrate region (11). On the other hand, the positive charge that accumulates in the defective contact (14) is not discharged to substrate ground G due to the open defect (14a). The induced surface voltage on the defective contact (14) from positive charge accumulation operates to modulate the intensity of secondary electron emission by creating potential barriers reducing secondary electron emission. In particular, the positive charge build up on the defective contact (14) decreases the intensity of the secondary electron emission as compared to the non-defective contact (13). Therefore, when the potential state of the scanned region (11) is acquired as a voltage contrast image, the lower potential non-defective contact (13) in the first region (11) might be displayed as bright (i.e., the intensity of the secondary electron emission is high) whereas the higher potential defective contact (14) is displayed as dart (i.e., lower intensity secondary electron emission).
However, in the second region (12), the positive charge that accumulates in the non-defective contact (15) causes the p/n junction (12a/12b) to be reversed biased, which prevents the accumulated charge on the contact (15) from being discharged to substrate ground G. Consequently, for low landing energies, positive charge accumulates on both the non-defective contact (15) and defective contact (16) in the second region (12), which causes the voltage contrast between such contacts to be dramatically reduced (e.g., contacts (15) and (16) are positively charged and will appear as dark regions in the SEM image). In this regard, although the contact (15) is not defective, the contact (15) can appear in the SEM image as a dark region providing a false indication of being defective.
Therefore, in the conventional process of FIG. 1, a second scan at a high landing energy would be needed to adequately detect voltage contrast defects in the second region (12). As shown in FIG. 8, the electron yield δ for tungsten at high landing energies is less than 1 such that negative charge would accumulate in the contacts (13, 14, 15 and 16). In the second region (12), the negative charge that accumulates in the non-defective contact (15) would cause the p/n junction (12a/12b) to be forward biased, which allows the negative charge to be discharged to substrate ground G. On the other hand, the negative charge that accumulates in the defective contact (16) would not be discharged to substrate ground G due to the open defect (16a). In this regard, the charge differential between the contacts (15) and (16) would result in differences in secondary electron emission and thereby resulting in voltage contrast differences suitable for voltage contrast defect detection.
However, in the first region (11), the negative charge that accumulates on the non-defective contact (13) would cause the p/n junction (11b/11a) to be reversed biased, which prevents the negative charge from being discharged to the substrate ground G. Thus, negative charge build up on both contacts (13) and (14) in the first region (11) would dramatically reduce the voltage contrast differences between such contacts and make the non-defective contact (13) to appear defective (as compared to the non-defective contact (15) in the second region (12)).
Therefore, in the conventional embodiment of FIG. 1, two separate electron beams scans at different landing energies are required (low and high) to enable voltage contrast inspection of electrical open defects of the contacts in the first and second regions (11) and (12). This is undesirable for several reasons. For instance, the need to perform two e-beam scans at different landing energies increases the inspection time and analysis and cost. Moreover, performing a second scan using a high landing energy beam is problematic in that the high energy electron beam can lead to significant charge accumulation of inspected features, which can cause distortions in an SEM image in way that decreases the efficacy of voltage contrast inspection. Moreover, the high-levels of accumulated charges that results from high energy electron beam scans can cause damage to certain semiconductor integrated circuit elements, thus lowering yield.

Semiconductor integrated test structures for electron beam inspection of semiconductor wafers

International Business Machines Corporation


A laundry room machine and a drying method thereof are provided. The laundry room machine may includes a payment device for collecting a payment for operation of the laundry room machine. The laundry room machine performs drying of laundry items for a preset dry time corresponding to a selected drying course. The drying method includes determining a condition of the laundry items by measuring a humidity level, and either sustaining the preset dry time or resetting a hot air supplying time and cooling time based on the determined condition of the laundry items.

In general, a laundry room includes machine for washing and drying the laundry. Such a machine performs only one of a washing operation and a drying operation, or both of the washing operating and the drying operation.
FIG. 1 is a flowchart illustrating a drying method of a laundry room machine according to the related art.
Referring to FIG. 1, the conventional drying method includes a payment insertion step S1 for inserting a card or a coin, a course selection step S2 for selecting one of drying courses according to characteristics of the laundry by a user, a drying step S3 for heating and drying the laundry for a time set according to the course selected at the step S2, and a cooling step S4 for cooling the heated laundry down.
However, the conventional drying method has following shortcomings.
Since a user selects one of drying courses regardless of the moisture content of the laundry, the laundry may be over heated and damaged.
Since the drying operation is continuously performed for a drying time of a selected drying course regardless of the condition of the laundry, the laundry is continuously heated although the laundry does not need to be dried any longer. Therefore, energy is wasted.
Since a user cannot extend a drying time while the drying operation is performing, a user must control a laundry room machine to perform a drying operation again after the current drying operation ends.

Drying method of laundry room machine and dryer therefor


An infrared detector capable of detecting an infrared spectrum having a wide bandwidth using a broadband light absorber. The infrared detector including a substrate, a light absorber disposed apart from the substrate at a distance, and a pair of thermal legs configured to support the light absorber such that the light absorber is spaced apart from the substrate by the distance. The light absorber includes at least one thermistor layer having a resistance value that varies according to temperature and at least two resonator layers disposed on at least one of upper and lower surfaces of the at least one thermistor layer.

1. Field
Example Embodiments relate to an infrared detector, and more particularly, to an infrared detector that is capable of detecting a wide bandwidth infrared spectrum.
2. Description of the Related Art
According to a principle of black body radiation, an object radiates a broadband electromagnetic wave that peaks at a specific wavelength according to a temperature. For example, an object radiates an infrared ray having a peak in a wavelength band at about 10 μm at room temperature. Bolometers are tools that absorb electromagnetic waves having an infrared (or terahertz) wavelength band radiated according to the black body radiation principle. The bolometer is configured to convert the absorbed electromagnetic waves into heat and then detect a temperature change due to the heat to measure radiation energy therearound.
Recently, in the development of micro electro mechanical system (MEMS) technologies, thermal imaging cameras in which a plurality of microbolometers are arranged in a two-dimensional array to acquire thermo images are being designed. To realize a high-resolution thermal camera having high temperature accuracy, a small-size pixel may be required. However, in a case where Salisbury screen type bolometers are used, in which a ground plate and a heat absorber are disposed at an interval of about λ/4 (where, λ is a centroid wavelength of an infrared wavelength band to be detected), when the pixel decreases in size, an energy amount incident into the pixel may be reduced. This reduction in incident energy may result in decreased absorption of heat resulting in a decrease in a temperature variation and a signal-to-noise ratio.
Lately, the use of bolometers using localized surface plasmon resonance (LSPR) is being proposed instead of using Salisbury screen type bolometers. Surface plasmon refers to a type of electromagnetic wave generated due to charge density oscillation of electrons that occurs on a surface of a metal. Bolometers using a plasmonic absorber may overcome limitations with respect to low absorption and low signal-to-noise ratio due to the LSPR.
However, since the plasmonic absorber may have relatively narrow bandwidth, it is difficult to effectively absorb heat in an entirety of the infrared region from about 8 μm to about 14 μm which is typically used for acquiring thermo images. Thus, various methods for increasing the resonance bandwidth of the plasmonic absorber are being proposed. For example, materials constituting the absorber may be substituted, or a plurality of resonators having different sizes may be disposed within one unit pixel.

Infrared detector including broadband light absorber


Methods, systems, and methods of manufacture for soft robotic actuators are described herein. In one aspect, a soft robotic actuator can include an elastomeric material defining a cavity; a volume of liquid metal (LM) positioned within the cavity; and an energy source coupled to the LM, where the energy source is adapted or configured to alter a temperature of the volume of LM, whereby altering the temperature of the volume of LM initiates an actuation of the elastomeric material.

Liquid Crystal Elastomers (LCEs) exhibit similar actuation behavior to natural muscle due to their dramatic contraction, reversible deformation, response to multiple stimuli, and great potential for micro-scale robotics. Combining liquid crystal orientation and cross-linked polymer networks, LCEs have attracted much attention towards creating artificial muscles. Mechanical alignment is the most widely used actuation option due to its convenience and ease of operation, offering the most potential for LCE actuators to mimic the large, linear actuation of natural muscle tissues. However, mechanical actuation includes significant drawbacks. For example, mechanical actuation can be heavy, particularly in relation to the material that is being actuated. Further, mechanical actuation is limited in its range of motion and degrades over time.
There is thus a need in the art for novel actuation systems that mimic natural muscle. The present invention addresses and meets this need.

Systems and methods of soft robotic actuation with a liquid metal actuator

The Regents of the University of Colorado, a body corporate


A method for fabricating a plurality of turbine components is provided. The method includes removably coupling at least one tab to a plate, wherein the at least one tab and the plate each include a plurality of apertures extending therein. The at least one tab is removably coupled to a first turbine component, and a tool is removably coupled to the plate such that the plate and the at least one tab substantially align the tool with respect to the first turbine component. The method further includes performing a fabrication operation on the first turbine component. The at least one tab is re-oriented with respect to the plate, and the at least one tab is removably coupled to a second turbine component. The tool is removably coupled to the plate such that the plate and the at least one tab substantially align the tool with respect to the second turbine component, and a fabrication operation is performed on the second turbine component.

This invention relates generally to mounting fixtures, and more specifically to a mounting fixture used to fabricate a plurality of different turbine engine components.
In known turbine engines, sometimes it is necessary to form openings that extend through a portion of the turbine. For example, sometimes is it necessary to drill openings through vertical flanges extending from a turbine casing. To drill horizontally, the drilling assembly must first be secured into position relative to the flange. To prevent movement of the turbine during the drilling, dowels are inserted through pre-formed apertures defined in the flanges. However, it may be difficult to secure the same drilling assembly to different engines, as the turbine engines may be sized differently, i.e. with different arc lengths, bolt spacings, and bolt radii, for example. Moreover, even within the same turbine such dimensions may vary from one portion of the engine to another portion of the turbine.
To align the drilling assembly with a portion of the turbine, at least some drilling assemblies use a mounting fixture. At least some known mounting fixtures are unitarily fabricated and are sized to enable the fixture to be coupled to the casing. As such, generally, a different fixture is needed for each different size of turbine or for each area of the engine. For example, a first fixture may be used on a portion of the casing formed with a first bolt spacing and a second fixture may be required on those portions of the casing formed with a second bolt spacing. In another example, one fixture is sized for use with a turbine rated for a first operation, while another fixture must be configured for use with a turbine rated for a second operation.
In one known fabrication method used to form apertures in a casing flange, several mounting fixtures with varying dimensions and configurations must be used to complete one drilling job. As such, several mounting fixtures unique to that turbine must be fabricated. Such requirements increase the costs and time of the aperture fabrication process. Furthermore, known fixtures are typically fabricated from solid steel, and, as such, may be awkward to move around and may be a hazard to those working with the fixtures.

Method and apparatus for fabricating a plurality of turbine components


Techniques are disclosed for a lighting fixture having spatial distribution control capabilities. In some cases, the lighting fixture may include an array of light modules that each contain one or more light sources (e.g., LED light sources) and multiple plates that can be used to control the spatial distribution (e.g., aim and focus) of the light modules. In such multi-plate lighting fixtures, the fixture may include a fixed base plate that includes multiple sockets for pivotally retaining a ball portion of each light module. The fixture may also include an XY plate that is movably coupled to the base plate and a focus plate that is rotationally coupled to the base plate, both plates including multiple slots that overlap to constrain a control arm of each light module. The multi-plate lighting fixture may be manually controlled or automated.

Lighting and lighting fixtures are becoming more dynamic, including the ability to control various aspects of the lighting, such as brightness/dimming, color, and spatial distribution. Spatial distribution of lighting may include the aim (target) and/or focus (spread) of the light provided by a fixture or system. One example of a lighting fixture that allows for spatial distribution control is a moving head lighting fixture, which is typically used in theater and stage lighting. In these fixtures, a lighting head unit is mounted on a motorized setup (e.g., double gantry or gimbal setup) that allows for directional aiming of a high intensity point light source. In addition, the moving head light may use optics for focusing/spot size adjustment. Moving head lighting fixtures, as well as other lighting fixtures that allow control of lighting spatial distribution, are controlled in many ways. Typically the fixtures are connected to a lighting control console, which sends signals to the motors or actuators of the fixture.
These and other features of the present embodiments will be understood better by reading the following detailed description, taken together with the figures herein described. The accompanying drawings are not intended to be drawn to scale.

Lighting fixture having spatial distribution control capabilities


A golf club holder includes an elongate body having a first end and a second end. A ground engaging member is positioned at the first end, whereby the elongate body is supported in a ground surface in a substantially vertical orientation. A socket is provided for detachably securing a first end of at least one golf club spaced from the first end of the elongate body. A clamp is provided for detachably securing a second end of the at least one golf club spaced from the second end of the elongate body.

There are very few golfers who are sufficiently skilled to consistently place a golf ball onto a golf green from a distance. Usually a golfer's fairway shoot will land in the vicinity of the green. The golfer will then use a pitching wedge to pitch the golf ball onto the green and then a putter to putt the golf ball into the hole. This requires a golfer to withdraw both his pitching wedge and his putter from his golf bag as he approaches the green. The golfer must place his putter onto the ground when making a shot with his pitching wedge, and then must place his pitching wedge on the ground when using his putter. There are a number of problems inherent in placing clubs onto the ground. One problem is the danger that the club will be inadvertently left behind. Another problem is sorting out, as between the golfers in a foursome, which club is whose. Yet another problem is the danger that the club will be accidentally stepped on resulting to injury to the golfer or damage to the club.
In order to address some of these problems, golf club holders have been developed. One example of such a golf club holder is sold under the Trade Name "GOLF BUTLER." This golf club holder is in the form of a shaft with a handle at one end and a ground engaging spike at the other. Extending transversely in relation to shaft is a member with a plurality of notches. A golfer rests a head of his golf club on the ground and then places a handle of the golf club into one of the notches with the golf club leaning up against the transverse member.


A programmable logic cell array (PLCA) architecture that provides efficient support for demultiplexers or multi-ported register files without sacrificing PLCA functionality or flexibility is disclosed. The architecture of conventional PLCs is modified so that demultiplexers can be implemented in a single PLC operated backwards. Furthermore, read ports and write ports for multi-ported register files can be implemented on a PLCA with individual PLCs serving as either a read port or a write port for a bit slice. In particular, a PLC memory of a PLC is modified such that it can function to pass signals to its inputs from a PLC multiplexer (selector) when the PLC multiplexer (built from a tree of pass transistors) is operated backwards so as to function as a demultiplexer (decoder). Moreover, a multi-ported register file be efficiently implemented by placing a register file on the PLCA and either modifying the PLC memory so that it operates in various modes (normal, forwards and backwards) or providing OR circuits for the write ports. In the normal mode the PLCs operate as conventional PLCs, in the forward mode the PLCs operate as read ports, and in the backwards mode the PLCs operate as write ports. The architectural modifications require very little additional circuitry beyond what is normally required by PLCAs. Moreover, the invention achieves a substantial compression in the number of PLCs needed to implement demultiplexers or multi-ported register files.

1. Field of the Invention
The present invention relates to a programmable logic cell array and, more particularly, to a programmable logic cell array architecture that efficiently supports demultiplexers and multiported register files.
2. Description of the Related Art
Programmable Logic Cell Arrays (PLCAs) are integrated circuits that contain configurable digital logic functions and routing resources. See e.g., Brandenburg et al., Poor Man's Gate Arrays: Logic Cell Arrays, IEEE Transactions on Nuclear Science, Vol. 35, No. 1, February 1988, pp. 213-216; Freeman, User-programmable Gate Arrays, IEEE Spectrum, December 1988, pp. 32-35. Through suitable programming, a PLCA can emulate a variety of different logic circuits. The ability to program and re-program PLCAs has proven to provide a great deal of flexibility to circuit designers.
The flexibility offered by PLCAs makes it possible to quickly prototype new logic designs without the expense of building the design from discrete components or fabricating the design in a custom integrated circuit. The trade-off, of course, is that since PLCAs are intended to support a wide variety of logic designs, the architecture of PLCAs must include routing and logic functionality that is unlikely to be used in all applications. Therefore, the efficiency or effective utilization of PLCA resources for a given application tends to be low compared to that which can be achieved in a custom integrated circuit implementation. This loss of efficiency is mitigated by the flexibility of the device, but there are some digital circuits which, when mapped onto a conventional PLCA, exhibit such extremely poor efficiency that implementing them in a PLCA (or a system of PLCAs) is impractical.
Because of their flexibility, PLCAs are important components in the construction of very high speed logic simulators or, more generally, configurable hardware systems (also called "virtual hardware"). See e.g., Kean et al., Implementation of Configurable Hardware using Wafer Scale Integration, 1990 International Conference on Wafer Scale Integration, pp. 68-73; Kean et al., Configurable Hardware: A new Paradigm for Computation, 1989 Decennial Caltech Conference on VLSI. In such applications, hundreds or thousands of PLCAs are connected electrically to form a prototype testbed for designing and experimenting with new digital system designs. A new design is "mapped" onto the simulator by programming the component PLCAs so that the simulator as a whole functionally emulates the behavior of the system being designed. This makes it possible to design, debug and test large, complex logic systems (such as computer processors, graphics engines, digital signal processing systems, etc.) much faster than is possible using conventional tools, such as software simulation and hardware prototyping.
An important component of many new high speed digital circuit designs (e.g., computer processor designs) is a multiported register file (an array of registers that can be read and written on many different ports simultaneously). Hence, in order for a logic simulator constructed from PLCAs to support the development of such digital circuit designs, it is desirable to map such register files onto PLCAs. Unfortunately, a serious problem exists which makes it impossible to map demultiplexers or register files into known PLCA architectures with sufficient efficiency to be practical.
When multi-ported register files are implemented with pure Boolean logic, they require a large number of gates. For example, an 80-bit wide file of 96 registers with four write ports and eight read ports requires more than 250,000 2-input gates or logic functions. It is estimated that such a multiported register file would require over 400 conventional PLCAs to be represented, if it can be done at all.
One might hope that expressing such a circuit in terms of 6-input, 2-output logic cells might lead to a significant reduction in the number of logic functions needed, since this has been observed to occur for many other circuits. For example, Xilinx Corporation of San Jose, Calif. has PLCA software that can take a circuit consisting of 2-input, 1-output gates and transform it to a logically equivalent circuit of 5-input, 2-output gates (logic functions), often achieving a reduction in the number of needed gates by a factor of 10 or more. However, this does not happen for demultiplexers (decoders) or multi-ported register files. For example, the register file mentioned above compresses to approximately 90,000 6-input, 2-output gates (logic functions), which is a very low amount of compression compared to many other circuits. Using PLCAs containing 256 6-input, 2-output logic cells (which is a fairly typical number of existing PLCAs) to implement the register file, would require a minimum of 350 of them, assuming infinite routing resources and no I/O pin limitations. Many more PLCAs that this are likely to be required in practice.
Another approach might be to handle a multi-ported register file as a special case by building it out of discrete components and interfacing it to the simulator. However, this approach is not practical for a number of reasons. One reason is that the special case approach requires a large number of discrete, off the shelf components (e.g., more than 100). Another reason is that the special case approach requires a large number of signals to be interfaced to the simulator (e.g., more than 1000). Yet another reason why the special case approach is impractical is because it is inflexible with respect to the register file parameters (e.g., bit width, number of registers, number of ports).
Thus, there is a need for a PLCA architecture that can efficiently support demultiplexers and multiported register files without sacrificing PLCA functionality or flexibility.

IC which can be used as a programmable logic cell array or as a register file


A phase change memory is provided, which includes a semiconductor substrate having a first conductive type, buried word lines having a second conductive type, doped semiconductor layers having the first conductive type, memory cells, metal silicide layers, and bit lines. The buried word lines are disposed in the semiconductor substrate. Each buried word line includes a line-shaped main portion extended along a first direction and protrusion portions. Each protrusion portion is connected to one long side of the line-shaped main portion. Each doped semiconductor layer is disposed on one protrusion portion. Each memory cell includes a phase change material layer and is disposed on and electrically connected to one of the doped semiconductor layers. Each metal silicide layer is disposed on one of the line-shaped main portions. Each bit line is connected to memory cells disposed on the word lines in a second direction substantially perpendicular to the first direction.

1. Field of the Invention
The present invention generally relates to a memory, in particular, to a phase change memory.
2. Description of Related Art
With the continuous progressing and evolution of the semiconductor technology, the manufacturing process of memory devices also strides forward towards physical limits. Thanks to the advantages of small volume, low power consumption, high read/write speed, high capacity density, and the like, a phase change memory (PCM) is considered as one of non-volatile memory devices that are developed with great efforts currently.
Generally speaking, the PCM takes a chalcogenide (Ge—Sb—Te) as storage media. The chalcogenide changes between two phases of amorphous and crystalline phases under different annealing temperature conditions, and the two phases have different resistances. Therefore, the high-resistance amorphous phase and the low-resistance crystalline phase may be used for the memory to store digital data of "0" and "1". Particularly, the two phases of the chalcogenide is reversible, so that the PCM can be repeatedly used for performing the operations such as programming, reading, and erasing.
In a conventional diode type PCM, a plurality of memory cells is disposed on a buried word line, and metal silicide layer is formed on the buried word line between memory cells. In other words, the metal silicide layer disposed on the word line is discontinuous. Therefore, when a current flows from a memory cell to a signal contact, a transmission path thereof not only includes the metal silicide layer, but also includes a substrate below the plurality of memory cells where the current flows. The resistance of the metal silicide layer is much smaller than that of the substrate, thus an impedance difference of the transmission paths between each of the memory cells on the same word line and the signal contact is rather large, which results in a large current difference and a large voltage difference between the memory cells when the data is read from or written into the memory cells on the same word line. And, the large current difference and the large voltage difference between the memory cells result in data misjudgment when a data is written in each of the memory cells or data reading error when a data is read from each of the memory cells.


In a half-bridge self-exciting switching power supply, an over-voltage detector receives the power supply output and generates an over-voltage signal when the power supply output exceeds a preset limit. An over-voltage cut-off circuit is connected to a pulse-width-modulated controller and a driving unit of the switching power supply. The over-voltage cut-off circuit applies a pull-down voltage to the driving unit so as to inhibit self-exciting operation of first and second self-excited switching circuits of a half-bridge self-excited circuit, and disables the pulse-width-modulated controller upon reception of the over-voltage signal from the over-voltage detector. Therefore, when the pulse-width-modulated controller or the driving unit becomes defective, the switching power supply can be cut-off automatically in order to prevent damage to a load and to the other components of the switching power supply.

1. Field of the Invention
The invention relates to power supplies, more particularly to a half-bridge self-exciting switching power supply with an over-voltage cut-off capability.
2. Description of the Related Art
Referring to FIG. 1, a conventional half-bridge self-exciting switching power supply is shown to comprise a rectifier circuit 1, a pulse-width-modulated inverter 2 and a power transformer unit 3. The rectifier circuit 1 includes a bridge rectifier (BD1) and capacitor filters (C1, C2). The pulse-width-modulated inverter 2 includes a half-bridge self-excited circuit 20, a pulse-width-modulated (PWM) controller 21 and a driving unit 22. The half-bridge self-excited circuit 20 is connected to the rectifier circuit 1 and includes a first self-excited switching circuit with a first transistor (Q1), and a second self-excited switching circuit with a second transistor (Q2). The driving unit 22 includes a driving transformer (T2) coupled to the first and second self-excited switching circuits of the half-bridge self-excited circuit 20, and first and second driving transistors (Q3, Q4). The power transformer unit 3 includes an isolation transformer (T1) coupled to the driving unit 22 and connected to the rectifier circuit 1. The isolation transformer (T1) provides two output voltages which are rectified and filtered by rectifier and filter circuits (not shown) to obtain two dc power supply outputs, namely +5V and +12V. The PWM controller 21 includes a voltage feedback circuit 210 which receives the dc power supply outputs, and a pulse-width-modulating unit (IC1), such as the 7500 or TL494 integrated circuit by Samsung. The pulse-width-modulating unit (IC1) is connected to the voltage feedback circuit 210 and the driving unit 22.
In operation, a 230V/110V ac line voltage input is processed by the bridge rectifier (BD1) of the rectifier circuit 1 before being filtered by the capacitor filters (C1, C2) in order to generate a higher voltage rectified dc signal, e.g. 300 volts, which is supplied to the half-bridge self-excited circuit 20 of the pulse-width-modulated inverter 2. Upon biasing, the first transistor (Q1) of the first self-excited switching circuit of the half-bridge self-excited circuit 20 conducts, thereby generating a current (I1) in the first self-excited switching circuit for energizing the driving transformer (T2) of the driving unit 22. Upon saturation of the first transistor (Q1), the first self-excited switching circuit is cut-off, and the second transistor (Q2) of the second self-excited switching circuit of the half-bridge self-excited circuit 20 is biased into conduction, thereby generating a current (I2) in the second self-excited switching circuit for continued energizing of the driving transformer (T2). The second self-excited switching circuit is cut-off when the second transistor (Q2) becomes saturated. The alternating conduction of the first and second self-excited switching circuits is referred to as a half-bridge self-exciting operation. Energizing of the driving transformer (T2) by the currents (I1, I2) of the first and second self-excited switching circuits enables the power transformer unit 3 to provide the +5V and +12V dc power supply outputs.
The voltage feedback circuit 210 of the PWM controller 21 provides the dc power supply outputs to the pulse-width-modulating unit (IC1). Upon comparing the dc power supply outputs with reference voltage values, the pulse-width-modulating unit (IC1) generates pulse drive signals for the first and second driving transistors (Q3, Q4) of the driving unit 22, thereby controlling the on-off ratios of the first and second self-excited switching circuits of the half-bridge self-excited circuit 20.
It can be understood from the foregoing that the conventional half-bridge self-exciting switching power supply relies primarily on the PWM controller 21 and the driving unit 22 to prevent over-voltage of the power supply outputs. However, if the PWM controller 21 or the driving unit 22 becomes defective, the self-exciting operation of the first and second self-excited switching circuits will go on uninterrupted. This is possible when the pulse-width-modulating unit (IC1) is unable to compare the dc power supply outputs with the reference voltage values, or when one of the first and second driving transistors (Q3, Q4) or the driving transformer (T2) is damaged. Uninterrupted self-exciting operation of the first and second self-excited switching circuits will result in the dc power supply outputs exceeding the required +5V and +12V values, thereby damaging the load (not shown) that is connected to the switching power supply. This is best illustrated in FIG. 2. After the power supply output peaks at (A), the power supply output then decreases due to internal damage of the switching power supply, as shown at (B) in FIG. 2.

Half-bridge self-exciting switching power supply with over-voltage cut-off capability


Rotatable circular plates are stacked apart to form thin air layers therebetween. Rotation of the circular plates moves air over an air treatment material: catalyst or adsorbent. In one embodiment, the air treatment material is affixed to the surface of the circular plates. In another embodiment, the circular plates are formed from the air treatment material. The increased velocity of air relative to the circular plates causes separation of laminar flow, promotes boundary-layer turbulence near the plate surfaces, and promotes propagating stall in the air layers. These phenomena enhance the contact between the flowing air and the air treatment material.

Hitherto, there have been practiced a number of air treatments by various means, for example, removal of ozone from ozone-containing air by ozone-decomposing means using an ozone decomposition catalyst, deodorizing of odoriferous air by odor-eliminating means using a deodorant, dehumidification of moist air by hygroscopic means using a drying agent, removal of dust from air containing tobacco smoke or the like by adsorptive removal means using an adsorbent, and addition of fragrance to air by fragrance-releasing means using a fragrant agent.
In some cases, the catalyst, deodorant, drying agent, fragrant agent, adsorbent or the like having the function of treating air as above is formed in a honeycomb shape and disposed in a stream of air to achieve the desired treatment. In other cases, surfaces of a sirocco fan or axial fan used for blowing air are coated with the deodorant or the like having the air-treating function, or, alternatively, the sirocco fan or axial fan itself is formed of a material having a drying function.
The conventional air treatment processes, however, had the following problems.
First, where a deodorant or the like having an air-treating function and formed in a honeycomb shape is placed in a stream of air so as to treat the air, in general, an improvement in the air-treating function per unit volume of the honeycomb-shaped deodorant or the like requires either a marked narrowing of the passage space in the honeycomb (so-called honeycomb pitch) to increase the surface area of the deodorant or the like, or an increase in the length of the passage formed by the honeycomb-shaped deodorant or the like to prolong the dwell time of air in contact with the deodorant or the like. The narrowing of the passage space involves an increase in the passage resistance in the honeycomb-shaped deodorant or the like, leading to the need for a higher fan capacity. An increase in fan capacity requires either a higher rotational frequency, which results in greater noise, or a larger fan size. On the other hand, an increase in the passage length requires the honeycomb-shaped deodorant or the like to be formed in a larger size.
Besides, these air treatment systems have been large and complicated in construction because they are composed of two members, namely, a fan member and the honeycomb-shaped deodorant o the like.
Secondly, where the impeller itself of a sirocco fan or axial fan is formed of a deodorant or the like having an air-treating function, an improvement in the air-treating function per unit volume of the impeller can be accomplished by various methods, for instance, by increasing the number of vanes or the length of vanes so as to prolong the dwell time of air. In this case, the passage resistance between the vanes is increased, with the attendant great reduction in the air flow rate across the fan. It is therefore necessary to contrive a higher fan capacity by an increased rotational frequency, an increased fan size or the like.
As a result, these air treatment systems have been accompanied by the problem of noise due to an increased rotational frequency or the problem of a large fan size.
It is accordingly an object of this invention to provide a process for air treatment by a multi-stacked rotatable plate assembly which is capable of solving the above-mentioned problems associated with the conventional types of air treatment systems.

Air treatment by multi-stacked plate asembly


Systems, methods, and computer readable storage mediums for generating an alert on a failure of a storage subsystem to phone home to the cloud in a replication environment. A dataset is replicated from a first storage subsystem to a second storage subsystem. The first and second storage subsystems also phone home log data to the cloud on a periodic basis. In response to detecting a failure of the first storage subsystem to phone home, the cloud generates and sends an alert to the second storage subsystem. In response to receiving this alert, the second storage subsystem starts disaster recovery operations for the dataset.

Technical Field
Embodiments described herein relate to storage systems, and more particularly, to techniques for monitoring storage subsystems in a replication environment.
Description of the Related Art
Business continuity and remote data protection are of paramount concern for enterprises. Unfortunately, most data protection and disaster recovery (DR) solutions require complex planning and significant investment to achieve the desired recovery point objective (RPO). More importantly, even if desired low RPO is achieved, the recovery times are much higher without making significant investments in DR solutions. Also, many DR solutions require DR site infrastructure to be identical to the production site, making the DR configurations restrictive. As a result of complexity, inflexibility, and economics, DR solutions are applied to only select few mission-critical applications or forgone completely.


The present invention provides a content locating method and a content delivery network node. In this case, the content locating method provided by the present invention comprises: receiving by a first content delivery network CDN node a service request sent by a service control function entity or an IPTV service control function entity, wherein this service request carries a content identifier which is used to indicate requesting content corresponding to this content identifier; if the first CDN node cannot provide the content service requested by the service request, then the first CDN node sends an inquiry request to a CDN global controller so as to acquire the information about a second CDN node which can provide the content service requested by the service request and request the second CDN node to provide the content service. By way of the present invention, the pressure of the CDN global controller can be reduced and the processing delay of CDN can be shortened.

The interactive network television, which is also called as Internet Protocol Television (abbreviated as IPTV), refers to a general term of the devices which provide users with, via an IP bearer network, services such as the live broadcast, video on demand, time shift playing and so on of the television programs which can support interaction capability. With the development of IPTV, the number of IPTV users increases continuously, which proposes higher requirements on the systems in terms of performance and reliability and so on. In this case, as to the content delivery function of interactive network, in order to reduce the interaction between the parts of the system, it requires that the internal modules of the content interaction network have definite functions and responsibility and requires that the content delivery and service procedure are brief and reliable.
Currently, the IPTV standards are mainly based on two kinds of architectures of Next Generation Network (abbreviated as NGN) IP multimedia subsystem (abbreviated as IMS) and NGN non-IMS, which can provide video on demand, live broadcast, video recording and some new services for the users.
The content delivery network (abbreviated as CDN) in the IPTV architecture plays an important role in aspects such as quality of experience (abbreviated as QoE) guarantee and system stability in the IPTV system. Each important function entity inside the CDN is mainly used for achieving content locating technology, scheduling and storage functions.
Currently, as to the content locating technology, both the content locating and playing require to be performed by a CDN master controller, and in the situation of a large scale of users concurring, the CDN master controller may cause processing delay, thus affecting system performance and becoming a bottleneck of system performance. Although processing delay can be reduced by the manner of increasing CDN master controllers to form distributed CDN master controllers to share loads, this manner increases the complexity and building costs of the CDN master controllers.

Content locating method and content delivery network node


The present invention relates to functionalized polymers including a poly(phenylene) structure. In some embodiments, the polymers and copolymers of the invention include a highly localized concentration of acidic moieties, which facilitate proton transport and conduction through networks formed from these polymers. In addition, the polymers can include functional moieties, such as electron-withdrawing moieties, to protect the polymeric backbone, thereby extending its durability. Such enhanced proton transport and durability can be beneficial for any high performance platform that employs proton exchange polymeric membranes, such as in fuel cells or flow batteries.

Membrane separators are key components in batteries and fuel cells. Currently, Nafion®, a perfluorinated polymer, is the current state of the art. However, Nafion® is costly. Non-fluorinated, hydrocarbons are more cost-efficient, yet exhibit poor oxidative stability, which in turn negatively impacts its durability. Thus, additional compositions are needed to provide improved polymers having enhanced oxidative stability without sacrificing performance. In particular, such improvements should allow the user to control or tune the amount or extent of the fluorinated or hydrophobic components of the polymer.

High performance, durable polymers including poly(phenylene)


The invention comprises a device for attracting and collecting flying insects. The device has an elongated clear plastic sleeve with a plurality of spaced passageways into the sleeve circumferentially around the sleeve to allow flying insects to travel therethrough into the interior of the sleeve. A fluorescent light is mounted centrally within the sleeve which can be illuminated to attract the flying insects toward the sleeve with the passageways in the sleeve allowing them to enter into the sleeve. A cone is mounted at the bottom of the sleeve having an enlarged upper end and a reduced lower end with downward converging tapered sides. A collection jar is detachably mounted to the lower end of the sleeve and surrounds the lower reduced end of the cone, whereby flying insects attracted into the sleeve, in circulating about in the sleeve, will be directed by the tapered sides of the cone through the reduced opening at the lower end of the cone into the jar where they will tend to remain captured within the jar. The jar is removable from the sleeve for emptying the jar of collected insects.

This invention relates to device for attracting and collecting flying insects and flying bugs and the like.
It is an object of the invention to provide a novel flying insect and flying bug attraction and collection device which has a novel clear, transparent sleeve with a series of passageways therethrough and a flourescent light within the sleeve to attract the insects and bugs toward the sleeve with the passageways allowing them to travel therethrough into the interior of the sleeve wiht a cone and collection jar at the bottom of the sleeve with the cone acting to direct the insects and bugs into the jar.
It is a further object of the invention to provide a novel transparent sleeve with illuminating means within the sleeve and with the sleeve having openings with tapered side to direct flying insects into the interior of the sleeve and with the illuminating means acting to attract flying insects toward the sleeve.
It is a further object of the invention to provide a novel attractive clear plastic sleeve illuminating means to attract and collect flying insects and the like.


A guide apparatus for guiding and arresting an elevator running on column-like guides automatically prevents a transmission of guide alignment errors to the car and an unintended engagement of the arresting device. A roller carrier for engaging the guide running surfaces is rotationally movably mounted on the car with a center of rotation at the longitudinal axis of the guide so that the roller carrier can follow a twist of the guide about its axis. The roller carrier also mounts an arresting device which is vertically displaceable in a mounting bracket by contact with a buffer on an abutment attached to the elevator car. In the case of an arresting braking of the car, no force is transmitted to the guide apparatus.

The present invention relates generally to an apparatus for guiding elevator cars and, in particular, to an apparatus for preventing transmission of guide alignment errors and an unintended engagement of the car arresting device.
Guide alignment errors usually are horizontal deviations from a vertical line generally parallel to the path of travel of an elevator car. In the case of column-like guides formed by extruded profiles, another type of alignment error can arise. Due to the manufacturing method, in particular for guide lengths of, for example, 5 to 6 meters, slight twists of a few degrees of angle about the guide axis are difficult to avoid. In consequence of the high stiffness and under consideration of the mode of installation used for this type of guide, it is not possible to reverse such a twist. It follows that elevator car guide devices for this type of guide must have a certain mobility in order to be able to accurately follow the guide path.
The Swiss Patent No. 386 651 shows a slide guide shoe which is carried in a ball socket and, due to this manner of mounting, has additional degrees of freedom for adaptation movements along a twisted guide path.
However, the principle of mounting by means of ball socket is not usable for guide rollers which encompass a column-like guide because the center of rotation of the car mounted guide equipment lies outside the guide cross-section and because this form of mounting has too many degrees of freedom for tracking movements for per se absolutely straight guides.
For the engagement of a conventional arresting device mounted on an elevator car, column-like guides include a projecting vertically extending brake leg. In the case of twist errors of the guide about its longitudinal axis, the leg could contact the arresting device and thus cause an unintended engagement of the same. To provide a greater air gap between an arresting device brake wedge and a brake surface on the guide as a countermeasure to unintended engagement is only conditionally possible due to the limited brake wedge travel and thus only partially solves the problem.
The U.S. Pat. No. 5,159,995 shows an elevator car wedge arresting device with two guide rollers. The two sprung guide rollers are firmly connected with the arresting device and have a limited spring travel which is less than the air gap between the brake wedge and the brake surface on the guide.
With this equipment, the air gap between the brake wedge and the brake surface must be dimensioned to be relatively large, because the spring travel of the guide rollers must be accommodated therein. An undesired reaction delay upon the triggering of the arresting device always results from this configuration. Moreover, a new arresting device must be constructed or an existing one rebuilt expensively.


A power tool that includes a motor sub-assembly, one or more batteries, and a cooling fan. The motor sub-assembly includes a motor and a motor fan. The one or more batteries are configured to provide power to the motor. The cooling fan is disposed vertically above the motor sub-assembly and the one or more batteries during operation of the power tool, where the cooling fan is configured to draw air in an upwards direction through the cooling fan, thereby dissipating heat from the motor and/or the one or more batteries, and where the upwards direction is the same a free convection direction associated with a density difference between hot air radiating from the motor and/or one or more batteries and surrounding cooler air.

This disclosure relates to cooling hand-held power tools and, in particular, to cooling a drum pump motor and battery assembly.
Removal of liquid contents from within drums has been effected in a variety of ways, such as by siphoning and/or providing a spigot on an end wall of a drum so as to permit the drum to be positioned in a horizontal manner for gravitational flow discharge of the liquid contents. Liquid dispensing procedures involving the pouring or discharge of the liquid contents through a spigot or the like require that the drum normally be positioned in a horizontal manner so that the drum occupies additional horizontal space with such positioning requiring substantial manual labor. Moreover, movement of drums from a vertical to a horizontal position frequently results in accidental spillage, dropping of the drums and/or physical injury to those in the vicinity and also can create a fire hazard when the contents of the drum are flammable.
Pumps have also been provided on drums for enabling the removal of the liquid drum contents. In some systems, the pump is coupled to a battery-driven motor configured to drive the pump and extract the liquid from the drum into smaller containers. One problem often encountered with such drum pumps is that the motor and/or batteries included in the drum pump generate heat that needs to be dissipated. Currently techniques for dissipating the heat include placing a separate fan near the motor and/or batteries such that the fan blows cool air over the motor and/or batteries to dissipate heat from the motor and/or batteries. Such a cooling system is typically referred to as "forced convection" since the cool air is forced over the heat source. However, such systems have proven to be ineffective at efficiently removing the heat from the drum pump motor and/or batteries.
Accordingly, there remains a need in the art for a system for cooling a drum pump motor and/or batteries that overcomes the limitations of prior approaches.

Cooling a drum pump motor and/or battery


Electrophoretically homogeneous human Antineoplastic Urinary Protein (ANUP) contains a blocked N-terminal amino acid that has been identified as pyroglutamic acid. Removal of the pyroglutamy residue by the use of pyroglutamyl aminopeptidose results in the formation of the deblocked protein which is also an antineoplastic molecule. The amino acid sequence of the deblocked ANUP 16 KD monomer showed the following sequence:. Cycle No.. 1. Leu L PA1 2. Lys K PA1 3. Cys C PA1 4. Tyr Y PA1 5. Thr T PA1 6. Cys C PA1 7. Lys K PA1 8. Glu E PA1 9. Pro P PA1 10. Met M PA1 11. Thr T PA1 12. Thr (T)? or Ser (S)? PA1 13. Ala A PA1 14. Ala A PA1 15. X?. Cycle No.. A data base search using the above sequence showed that 100% homology with another protein was not found regardless of unassigned positions.. The blocked N-terminal amino acid of ANUP is pyroglutamic acid.

Field of the Invention
The present invention relates to the partial primary amino acid sequence of the N-terminal amino acids of ANUP after removal of the N-terminal pyroglutamyl residue. This antitumor cytokine is present in human granulocytes and is excreted from the serum into the urine, since the protein is also present in the serum.
Generally in accordance with the present invention, the electrophoretically homogeneous ANUP (monomer 16 KD) is treated with pyroglutamyl aminopeptidase to liberate the free N-terminal amino group. The deblocked protein is transblotted and the amino acid sequence of the electrophoretically homogeneous deblocked protein is determined.

Parital primary amino acid sequence of the antineoplastic protein (ANUP); a cytokine present in granulocytes


A proximity detector including a sensor unit that produces an analog signal and a processor circuit digitizing this signal. The processor circuit includes logic that determines a switching value from an initial value and an extreme value obtained during a learning mode.

1. Field of the Invention
The present invention concerns a proximity detector of the inductive, photoelectric or any other type, comprising a sensor unit adapted to deliver an analogue detection signal according to the range of a target and an electronic processor circuit connected to an output stage that delivers a signal indicating the presence or the absence of a target according to whether the range of the target is less than or greater than a switching distance.
2. Discussion of the Background
The switching distance specific to a detector of this kind varies from one equipment to another and, for the same equipment, with its installation or environmental conditions, in particular in the case of an inductive detector embedded in a mass of metal or a photoelectric cell operating with a bright background.
It would therefore be useful to be able to calibrate the proximity detector in situ.
It has previously been proposed (see document DE-43 31 555) to calibrate a proximity detector in the factory or on the user's premises using control logic to which a non-volatile memory and a counter are connected. An object is placed at a predetermined fixed distance from the detector and counting is started when the logic is activated by a calibration signal; the count value is passed through a digital-to-analogue converter and then compared with the value of the detected signal; as soon as it reaches this value, the count is stopped and the corresponding value is placed in memory. However, a device of this kind cannot be used with a target that moves during the calibration phase.


A system and method for intelligent management of an array of fans. The system uses mean-time-between-failure, fan usage and other data in add ventilation, subtract ventilation and recycle array routines to maximize the life of the fans and the array. The system comprises a primary embodiment making use of smart fans in the array, each smart fan including a fan and appropriate control electronics capable of processing commands received from a smart fan array controller. Fan control signals are multiplexed over a local operating network power line using carrier communication protocols, command messages and data values, all to accomplish a goal of the system to maximize fan life. In an alternate embodiment, fan and array control electronics are integrated onto the fan array controller itself and power is provided to conventional fans using a conventional wiring harness.

Mean-Time-Between-Failure (MTBF) and Duty Cycle for Fans
Fans, or blowers, are used to move air in a desired direction. Such fans can be used in a variety of applications, including but not limited to ventilating and cooling an area such as attic space, protecting components from overheating such as in a desktop, or larger, computer housing, evacuating humid or moist air such as in a bathroom after a shower, or evacuating hazardous gases or smoke from an area in a fire protection or other environmental control system.
Such fans are rated by a manufacturer specification of mean-time-between-failure (MTBF) designating the number of hours that the fan, on average, will run before it risks end of life types of failure. Thus, the MTBF of a particular type of fan is referred to as a predicted elapsed time between failures of the fan during operation, and it is calculated by the manufacturer as the arithmetic mean (average) time between failures for that type of fan.
MTBF is often expressed in connection with a duty cycle requirement for a fan. Duty cycle for a fan is defined as the ratio of the on-time fan operating duration to a total period (both on and off combined). Thus, a fan may be rated by its manufacturer with a particular MTBF assuming a duty cycle of no more than 75% on and 25% off for each hundred-hour period of fan life. If a particular system design requires fan usage in excess of the specified duty cycle for the fan, full useful life of the fan would not be achieved on average.
After a fan has run for the rated time according to its MTBF, failure may be anticipated and the fan may be replaced prior to failure during scheduled maintenance of the system. Thus, an understanding and application of MTBF, duty cycle and system maintenance are important since critical failure of a fan may lead to a variety of failures including but not limited to overheating damage, mold and mildew damage, and enhanced damage or injury from hazardous gases and smoke, depending upon the purpose for which the fan or fans have been deployed.
The replacement and repair of individual fans may in some cases be inconvenient, and especially so where the fans are not readily accessible, such as on a highly pitched rooftop or inside of a computer system that must be turned off in order to access the fans. One means of addressing the cost and inconvenience of fan failures has been to purchase higher-quality, typically more expensive, fans in order to increase MTBF. A downside to this approach is the higher up-front expense of installing and replacing such a system.
Fan Arrays
Another means of addressing the inconvenience and cost of replacing and repairing individual fans, as well as providing a higher-efficiency system for meeting system demands, has involved the development of redundant fan systems, or an array of fans, used in an effort to provide a longer-life system. Consideration of MTBF and duty cycle ideally applies to fan arrays, as well as single fans, and these concepts are an important part of scheduling repair, renewal and maintenance of fan arrays. However, prior art fan array systems have paid little or no heed to MTBF and duty cycle considerations in fan arrays.
Fully Redundant Fan Arrays
An array of fans may be fully redundant, partially redundant or not redundant at all. In a fully redundant system using switched identical fans, the overall MTBF of the system is increased by a multiple of the amount of redundancy employed. In the simplest of such systems using a plurality of identical fans, a first fan would simply run, or be available, until it fails, and then successive fans would be employed, and so on in a series-switched system, until the last fan in the system has been used up. In such a case, the overall MTBF of the array would have been the product of the number of fans and the MTBF of an individual fan: system MTBF=n×MTBF, where n=the number of fans. Where multiple types of fans with different MTBF characteristics have been employed in a single such system, the system MTBF would have been expressed as a sum of the MTBF for each fan in the array. Cost savings in a fully redundant fan array has been primarily associated with enhanced avoidance of failure associated damages and any economies of scale of volume purchasing, volume installations and volume repairs. More importantly, increase of lifespan of such fully redundant switched arrays beyond that normally expected by increasing the redundancy of fans in the array, has not occurred with and has not been a stated goal of such prior art fan arrays.
A suitable example of a fully redundant array system would comprise three identical fans, where one fan alone has provided sufficient capacity to meet demand, and two of the fans have been considered as backup fans. Absent volume purchasing and installation cost savings, such a system would have cost three times as much in terms of fan costs and installation as a single fan system, and the life of the array may have been expected to have lasted approximately three times as long as a single fan. Thus, though using such an array has been more convenient than a single fan from a maintenance and repair perspective, there has been no appreciable additional cost savings or enhancement of the life of the array beyond the sum of the MTBFs of each fan in the array.
The foregoing arrays are representative of fully redundant arrays, and the same basic MTBF and duty cycle considerations would hold true regardless of whether a single fan is used at a time or multiple fans are used at capacity at a time, assuming complete redundancy. Thus, for example, where two full duty cycle fans at capacity are needed to meet demands, and serial switching is employed, 3× redundancy would assume a system with six fans, and so on, and the same limitations on cost savings and enhanced system MTBF would apply.
Non-Redundant Fan Arrays
Non-redundant fan arrays involve a system where all fans in the array are used essentially at or near maximum duty cycle. While in such a case greater performance effectiveness and perhaps efficiencies have been accomplished by implementing an array, such a prior art array has not been employed so as to have enhanced the overall MTBF of the system beyond the rated MTBF of one of the fans of the system.
Partially Redundant Fan Arrays
Partially redundant arrays of fans have typically involved the use of control systems for determining the number of fans to be used in parallel, depending upon need, to meet requirements. Partially redundant arrays of fans have been developed primarily for HVAC systems where variable demands for cooling and ventilation have been required by an external device such as a thermostat, an emergency fire or hazardous air abatement and control system, a remote control device or a user-operated or automated switch. Accordingly, such systems have involved simultaneous use of multiple fans in a parallel array to meet varying system demands, for example for use during higher-temperature or higher-humidity periods.
Thus, for example, a partially redundant array of fans has comprised three fans that are all available in parallel to maintain thermostat readings in a cooling system at below a predetermined maximum. As the object of the cooling system, for example a building or a main frame computer system, has generated more heat than is able to be cooled with a single fan, additional fan power has been automatically added with control means responsive to data received from the thermostat. Further, such partially redundant fan arrays have incorporated application of remaining fan power upon encountering a failed fan in the system, similar to the serially-switched, completely redundant systems described above.
An example of such a system is found in U.S. Pat. No. 6,826,456 to Irving, et al., for System and Method For Controlling Server Chassis Cooling Fans, which teaches temperature sensing for controlling prior art fans that has included either an on-board, or an external, temperature sensor that has controlled the turning on and running of fans based upon increased temperature readings from the temperature sensor.
In conjunction with prior art fan array systems, whether they be fully redundant, partially redundant, or not redundant, there have been developed minimal signaling and reporting capability by failed fans. For example a system has been described in US Patent Application Serial No. 2006/0176186 to Larson et al., for Fan Monitoring for Failure Prediction, that has automatically notified an information technology professional when a fan of a fan array in a computer system is predicted to fail. This has allowed the IT professional to replace the fan or fan array, for example in a hot swappable fan system wherein the overall computer system has continued to operate while the fan, or fan array, has been removed and replaced.
Also, as demonstrated by U.S. Pat. No. 6,824,362 to Dodson III, for Fan Control System, other prior art fan array systems have employed an on-board tachometer that has been capable of actuating an alarm for under-speed fan conditions, thus signaling a potential critical fan failure or needed repair.
As may be appreciated from the foregoing description, partially redundant systems have presented a more complicated scenario for considering system MTBF and duty cycle, since each such partially redundant fan array system has presented widely diverging and unique capabilities to meet widely varying demands.
While there have been developed simple fan array controllers for determining the number of fans deployed responsive to an external device, such as a thermostat or a fire control system, and while there have been deployed fan array systems incorporating minimal fan data transfer and consideration by such a controller to accomplish simple management tasks, such as replacing a hot-swappable fan, a system for enhancing fan array life based upon static and dynamic fan data received from fans in the array has not been found in the prior art.
Thus, there has been lacking in the prior art a fan array system that has the intelligence for making determinations about which fans to use based upon demand, static fan data, such as rated MTBF, duty cycle and rated power consumption, rated temperature and rated speed, and dynamic fan data, such as hours in use, actual power consumption, revolutions per minute, and calculated remaining life, to enhance the MTBF of a fan system. Further, prior art systems have not allowed for inclusion of fans having differing MTBFs or other characteristics in a single array in a way that determines use based upon fan capability in order to enhance overall MTBF.


A detector with quantum structure comprising a small-gap semiconductor material inserted between two large-gap semiconductor materials, the structure comprising a coupling grating between the wave to be detected and the detector zone constituted by the small-gap material. Under these conditions, the detector zone may have a very small thickness (typically of the order of 1,000 .ANG.) and lead to a detectivity, limited by the dark current, that is high.

The field of the invention is that of detectors with quantum well structure working in the infrared range, both in band II (between 3 and 5 .mu.m) and in band III (between 8 and 12 .mu.m).
At present, there are three types of detectors used in the infrared domain.
A first type relates to the detectors with Schottky junction formed between silicon and platinum silicon (Si/PtSi). These detectors perform well (as measured by a minimum temperature detectable commonly called NETD or noise equivalent temperature detectable of about 80 mK in band II for reading frequencies of 50 Hz, surface areas of 50 .mu.m.times.50 .mu.m and an optical aperture of f/2), but have very low working temperatures (of about 77 K).
A second type relates to bolometrical or pyrometrical thermal detectors based on the changing of electrical properties such as the dielectric index or the resistance under the effect of heating due to the radiation absorbed. These detectors lead to more modest performances (with NETD values of about 120 mK under the conditions of measurement described here above and for band III). Nevertheless, their great value is that they work at ambient temperature without needing to be cooled.
A third type of detector relates to quantum structure detectors using p-n junctions based on semiconductors such as InSb, HgCdTe or PbSnSe or intersubband transitions in quantum wells of materials such as GaAs/AlGaAs.
These detectors have very high performance characteristics (with NETD values in the neighborhood of 20 mK) but work at temperatures in the range of 200 K in the best cases.
These last-mentioned detectors which perform very well therefore require cyrogenic cooling. This represents an extra cost for the equipment.
Indeed, as described in R. J. Keyes, "Optical and Infrared Detectors", Springer-Verlag, the detectability of a component of this type is proportional to I/.sqroot.I.sub.dark where I.sub.dark is the dark current of the detector. In semiconductor-based quantum structure detectors, the current I.sub.dark is thermally active, namely it varies as a function of the temperature in the form I.sub.dark .alpha.e.sup.-Eg/jkT
where Eg is the width of the gap of the semiconductor, close to the energy of the photon to be detected.
More specifically, the dark current in a photovoltaic detector is given by the following equation:
I.sub.dark =I.sub.diff +E.sub.ZCE
with I.sub.diff =q L.sub.diff .multidot.n.sub.i.sup.2 /.tau..sub.min .multidot.N.sub.dop
and I.sub.ZCE =q n.sub.i d/.tau..sub.min
where:
I.sub.diff is the diffusion current
I.sub.ZCE is the space charge zone current
L.sub.diff is the diffusion length (typically some tens to some hundreds of microns)
.tau..sub.min is the lifetime of the minority carriers
n.sub.i is the intrinsic carrier density
d is the thickness of the space charge zone.
FIG. 1 illustrates a standard photovoltaic detector having a p-n junction in which the lengths L.sub.diff and d are shown.
In these detectors, it is particularly n.sub.1.sup.2 that gives the thermally activated term. Conventionally, by cooling these infrared detectors, the dark current and therefore the associated noise are reduced. Furthermore, since the dark current is proportional to the thickness d of the detector zone, it is judicious to have a very thin detector zone. More specifically, the detectivity limited by the dark current is given by the formula:
D*=.eta..lambda./[u.sup.1/2 hc. (I.sub.dark /qG.sup.2 A).sup.1/2 ]
where
q is the charge of the electron
h is Planck's constant
c is the velocity of light
k is the Boltzmann constant
T is the temperature
G is the gain in photoconduction (G=1 if the component is photovoltaic)
u=2 if the component is photovoltaic
u=4 if the component is photoconductive, and
.eta.=the quantum yield given by the absorption of light in the layer with a thickness d giving: EQU .alpha.=1-e.sup.-.alpha.d
where .alpha. is the coefficient of absorption of the material.
The detectivity D* is therefore proportional to: EQU D*.alpha. .eta.(d)/.sqroot.d
and in the standard case .eta.(d)=1-e.sup.-.alpha.d
FIG. 2 illustrates the development of the detectivity D* as a function of the thickness d. The curve 2a relates to standard quantum detectors in which .eta.(d)=1-e.sup.-.alpha.d, these detectors typically using thicknesses in the range of one micron. The curve 2b pertains to a quantum detector in which .eta.(d) is constant. With this type of detector, it becomes particularly useful to work with a very low thickness d which may be in the range of 0.1 .mu.m and a constant quantum yield .eta., the very low thickness d leading to low dark currents that no longer require any device for the cooling of the detector.

Infrared detector with non-cooled quantum well structure


A digitally programmable Bessel filter includes a plurality of serially connected stages or biquads with each biquad including a plurality of programmable operational transconductance amplifiers. The first stage of the filter provides an all pass equal amplitude response. Two stages provide pulse slimming (first and second derivatives of an input pulse), and three stages provides a sixth order Bessel low pass function. The operational transconductance amplifiers are controlled by a fine tuning control signal, and an array of integrating capacitors are selectively controlled by a coarse tuning signal. The fine tuning and coarse tuning signals are generated in a phase locked loop from a reference clock and a reference biquad which receives the reference clock. The phase locked loop includes a phase detector responsive to the reference clock and the reference biquad, whose output is integrated.

This invention relates generally to electrical filters and more particularly the invention relates to a linear phase filter using programmable operational transconductance amplifiers.
In recovering signals stored optically or magnetically on a tape or disk, pulse shaping and filtering circuitry is required. The conventional filter for reading magnetically stored data, such as stored on tape or disk, is built with passive discrete components in a circuit which is designed for implementing only one particular phase/amplitude response and therefore for only one type of pick up head. The performance of the read channel is measured to the bit error rate and since the conventional read channel filter has a fixed response, any given filter contributes to lower the bit error rate for a particular head type only. Passive components typically used in such filters are analog devices which cannot be readily altered. However, an analog programmable seven pole Bessel type low pass filter is currently available from Silicon Systems, Tustin, Calif.

Digitally programmable linear phase filter having phase equalization


A system and method for corrosion problems in magnetic media resulting from moisture penetrating through the carbon layer into the magnetic layer by diffusion or other methods are overcome by processing the carbon overcoat to stop and/or inhibit the moisture penetration. The process involves removing moisture channels from protective overcoats of thin film magnetic media by irradiating the protective overcoat with ultraviolet (UV) radiation in an inert hydrophobic chemical environment. Afterwards, the thin film magnetic media can be removed into ambient atmosphere where it is coated with a lubricant.

1. Field of the Invention
The present invention relates generally to the field of disc drive storage, and more particularly to improved corrosion resistant magnetic media used in disc drives.
2. Description of the Related Art
Computer disc drives commonly use components made out of thin films to store information. Both the read-write element and the magnetic storage media of disc drives are typically made from thin films.
FIG. 1A is an illustration showing the layers of a conventional magnetic media structure including a substrate 105, a seed layer 109, a magnetic layer 113, a diamond like carbon (DLC) protective layer 117, and a lube layer 121. The initial layer of the media structure is the substrate 105, which is typically made of nickel-phosphorous plated aluminum or glass that has been textured. The seed layer 109, typically made of chromium, is a thin film that is deposited onto the substrate 105 creating an interface of intermixed substrate 105 layer molecules and seed layer 109 molecules between the two. The magnetic layer 113, typically made of a magnetic alloy containing cobalt (Co), platinum (Pt) and chromium (Cr), is a thin film deposited on top of the seed layer 109 creating a second interface of intermixed seed layer 109 molecules and magnetic layer 113 molecules between the two. The DLC protective layer 117, typically made of carbon and hydrogen, is a thin film that is deposited on top of the magnetic layer 113 creating a third interface of intermixed magnetic layer 113 molecules and DLC protective layer 117 molecules between the two. Finally the lube layer 121, which is a lubricant typically made of a polymer containing carbon (C) and fluorine (F) and oxygen (O), is deposited on top of the DLC protective layer 117 creating a fourth interface of intermixed DLC protective layer 117 molecules and lube layer 121 molecules.
The durability and reliability of recording media is achieved primarily by the application of the DLC protective layer 117 and the lube layer 121. The DLC protective layer 117 is typically an amorphous film called diamond like carbon (DLC), which contains carbon and hydrogen and exhibits properties between those of graphite and diamond. Thin layers of DLC are deposited on disks using conventional thin film deposition techniques such as ion beam deposition (IBD), plasma enhanced chemical vapor deposition (PECVD), magnetron sputtering, radio frequency sputtering or chemical vapor deposition (CVD). During the deposition process, adjusting sputtering gas mixtures of argon and hydrogen varies the concentrations of hydrogen found in the DLC. Since typical thicknesses of DLC protective layer 117, are less than 100 Angstroms, lube layer 121 is deposited on top of the DLC protective layer 117, for added protection, lubrication and enhanced disk drive reliability. Lube layer 121 further reduces wear of the disc due to contact with the magnetic head assembly.
FIG. 1B is an illustration showing an enlarged view of the DLC protective layer 117 with pinholes that allow moisture to penetrate through the DLC protective layer 117 and cause corrosion. DLC protective layer 117 includes first pinhole 130, second pinhole 132, third pinhole 134, fourth pinhole 136, and fifth pinhole 138. Water molecules 140 condense on the surface of DLC protective layer 117 and migrate down into the pinholes. Some of the pinholes are deeper than others. Water molecules can migrate down the deeper holes and corrode the magnetic layer 115. Although, the deeper pinholes have a higher chance of causing corrosion in the magnetic layer, corrosion can still occur when water molecules are trapped in the more shallow pinholes.
One way water molecules 140 condense on the surface of the DLC protective layer and migrate down the pinholes is when the magnetic media structure is taken out of the vacuum chamber and transported to the lubrication station where the lube layer 121 is deposited over the DLC protective layer 117. This transfer process usually involves moving the magnetic media structure without the lube layer 121 in an ambient atmosphere that contains moisture. Once the water molecules 140 have condensed on the surface of the DLC protective layer 117 they will be trapped there by the subsequently lube layer 121 if they are not removed before applying the lube layer 121. It is important to note that even if the water molecules 140 are removed, the lube layer 121 must be applied before the water molecules re-condense on the surface DLC protective layer 117. This can be a difficult task considering that the lubrication process is usually done by dipping the media in a tank of lubricant material, as is further discussed with reference to FIG. 1C below.
FIG. 1C is a flow chart showing the typical steps used to deposit a carbon overcoat and lubrication layer of the magnetic media structure shown in FIG. 1A. The process begins with step 150 by transferring a partially complete media with substrate 105 and seed layer 109, into a vacuum chamber. The transferring process typically involves moving a disk, after depositing the seed layer 109 on it, into a deposition chamber used to deposit metals that make up the magnetic layer 113 without taking it out of vacuum. Next in step 155, the magnetic layer 113 is deposited onto the seed layer 109 using conventional thin film deposition techniques such as sputtering, CVD, PVD etc. The magnetic layer 113 can be a single layer or can comprise multiple layers of both magnetic and non-magnetic materials. For example a typical magnetic layer can consist of 20 bi-layers consecutively stacked on top of each other with each bi-layer consisting of a magnetic layer and a non-magnetic layer. These materials are all deposited in step 155 to make up the magnetic layer.
Next in step 160, the substrate with the magnetic layer 113 is moved to the protective layer deposition chamber where a protective overcoat layer 117 is deposited on the magnetic layer 113. In step 160, the protective layer 117 consisting of an amorphous carbon is deposited over the partially complete media. Typically the amorphous carbon layer is diamond like carbon (DLC) that has been deposited by conventional sputter deposition techniques. Next in step 165, the amorphous carbon is removed from the deposition chamber and moved into a lubrication station. Typically, this involves removing the magnetic media with a carbon containing overcoat from the vacuum chamber and moving it in atmosphere to the lubrication station. Next in step 170 the protective overcoat 117 is coated with a lube layer 121 using a dipping process wherein the magnetic media having a protective overcoat is dipped into a bath of lubricant and the lubricant is consequently drained from the bath leaving a layer of lubricant on the protective overcoat 117. The lubricant can contain Moresco lubricant or PFPE. Finally, in step 175 the lubed magnetic media is transferred to the next manufacturing operation.
In step 160, the lube layer 121 can be applied using several processes including dipping the magnetic media, which has a protective layer 117, into a tank of lubricant fluid or vapor lubing the disk. If the lube layer 121 is applied with a dipping process, the magnetic media with protective layer 117 is first taken out of vacuum and dipped into a tank of lubricant fluid.
In the dipping process, lube layer 121 is typically applied evenly over the disc, as a thin film, by dipping the discs in a bath containing a mixture of a few percent of the lubricant in a solvent and gradually draining the mixture from the bath at a controlled rate. The solvent remaining on the disc evaporates and leaves behind a layer of lubricant less than 100 Angstroms.
When the magnetic media containing amorphous carbon is removed from the deposition chamber and moved into a lubrication station, in step 165, the exposed carbon layer is subjected to moisture, which causes corrosion. Moisture is one of the indispensable ingredients for media corrosion at typical drive operation environments. Moreover, moisture that penetrates the carbon layer and reaches the magnetic layer is one of the most likely causes of corrosion in hard disk drives. As carbon layer become thinner this problem becomes more serious because it is easier for moisture to penetrate through the thinner carbon layer and corrode the magnetic layer. Performance of hard disk drives is heavily dependent on the corrosion resistance of the media.
Therefore what is needed is a system and method that overcomes corrosion problems by stopping and/or inhibiting moisture from penetrating through the carbon layer into the magnetic layer by diffusion or other methods. Additionally, a system and method that reduces corrosion problems of a magnetic disk is needed that prevents moisture from diffusing through both the carbon protective layer and the lubricant overcoat.

System and method for improving corrosion resistance of magnetic media