A secure system and method is provided for remotely waking a computer from a power down state. In one embodiment, a network interface card receives incoming data packets via a network connector. A control module is coupled to the network connector and is configured to search the incoming packets for a wake-up pattern. The control module also verifies that the packet""s destination address matches the destination address of the network interface card. If the destination addresses match and a wake-up pattern is found, the control module decrypts an encrypted value from the incoming packet and compares the result to an expected value. A successful comparison causes the control module to assert a signal to wake up the host computer. Preferably, a standard public/private key pair encryption scheme is used, and the source of the data packet encrypts the expected value with a private key. All computers which may receive wake-up packets are provided with a public key with which to decrypt values contained in a security field of any wake-up packets. A successful decryption serves to certify that the wake-up packet was transmitted from an authorized source. For added security, the expected value and public/private keys may be changed on a regular basis, or even every time a valid wake-up packet is received. The new value may be provided in the wake-up packet, to be stored by the network card for the next use.

1. Field of the Invention
The present invention relates generally to network computing systems, and more particularly, to a secure method for remotely waking up a computer on a network.
2. Background of the Invention
Computer networks are commonly used in offices or corporate environments to interconnect personal computers. Well-known local area networks (LANs), such as Ethernet, Token Ring, and ARCnet, are widely used to interconnect a group of computers and other devices that are dispersed over a relatively limited area, such as an office or building, and new LANs continue to be developed. These local area networks provide an efficient and economical way for personal computers to share information and peripherals.
Of course, computer networks are not limited to the confines of an office or building. Smaller networks are commonly interconnected into wide area networks (WANs), such as the Internet, to provide a communications link over a larger area. The Internet is actually a collection of networks that share the same namespace (a set of names in which all names are unique) and use the well-known transmission control protocol/internet protocol (TCP/IP). The Internet currently connects over four hundred networks and tens of thousands of nodes in over forty-two countries. It is estimated that the Internet is now accessed by more than 10 million people every day.
As is well known in the art, the transmission of data packets across networks is governed by a set of rules called xe2x80x9ctransport protocolsxe2x80x9d. In order for two computers in a local area network to communicate with one another, each computer must use the proper transport protocol for the particular network. During the last decade, many different transport protocols have evolved for use in different networks. For example, TCP/IP is the transport protocol widely used in UNIX based networks and with Ethernet 802.3 LANs; IPX/SPX is the transport protocol used by Novell Corporation""s NetWare developed by IBM to operate underneath Microsoft""s NetBIOS network interface; DECnet is the transport protocol used by Digital Equipment Corporation for linking computer systems to DECnet-based networks; AppleTalk is the transport protocol developed by Apple Computer, Inc. for linking systems to Apple Macintosh network systems; and XNS is the transport protocol developed by Xerox Corporation that was used in early Ethernet networks. The transport protocols, which are all well known in the art, are often implemented as software drivers which can be loaded into and out of a computer system.
In order to connect to a network, a computer is usually provided with one or more network interface cards (NICs) that provide a data link to the network. Each network interface card has a unique address, referred to herein as its xe2x80x9cdestination addressxe2x80x9d, which enables each computer to be individually addressed by any other computer in the network. The destination address is typically, but not always, a 12 digit hexadecimal number (e.g., 00AA00123456) that is programmed into memory located on the network interface card and is generally hidden from the user""s view. Users are not expected to know and remember the destination address of every computer in the network. Instead, every computer generally has a computer name (commonly corresponding to the user""s name and/or machine location) that is more widely known. When a user desires to send a message to another computer, the transport protocol in the network is responsible for converting the name of the other computer into the corresponding destination address to establish a communications link between the two computers.
Because wide area networks often include a collection of a wide variety of machines, organizations and individuals, these networks must provide the means to exchange data between dissimilar machines and across many different transport protocols. Each transport protocol has its own version of addressing information that enables it to exchange electronic mail, data files, programs, etc. between one LAN and another LAN. As a data packet is transmitted across different networks, the addressing information for one transport protocol is replaced by the addressing information for the next transport protocol. Over the Internet, this LAN addressing information is abstracted from the Internet address.
The address of an individual, computer, or organization on the Internet has several layers or components including the domain name or user name, the underlying identifiers used by the transport protocol(s) that govern the data exchange, and the actual destination address. Each transport protocol is designed to extract the appropriate destination address to ensure that each message packet is routed to its intended recipient.
To illustrate the distinctions between the various layers of addressing information, consider an individual computer user in Atlanta that wishes to send an e-mail message to a destination computer in Seattle where the computer in Atlanta is connected to an Internet service provider and the computer in Seattle is connected to a corporate local area network. Generally, the user in Atlanta will know, or can readily obtain, the recipient""s computer (e.g., www.recipient.com), but will not know the recipient""s Internet address or actual destination address. Nonetheless, the transport protocols will abstract the destination address from the message packet as it is transmitted across the network.
Therefore, the user in Atlanta will simply type the recipient""s computer name, www.recipient.com, as the address of the destination computer. The message packet will be sent via the Internet, where the TCP/IP transport protocol will convert the computer name into a more primitive Internet address, which is a 32-bit value that identifies the host""s network ID and host ID within the network, e.g., 188.8.131.52. The message packet is then routed to the corporate LAN in Seattle, where a component in the LAN, typically a network router, switch, or server, converts the Internet address into the destination address of the recipient""s network interface card, e.g., 00AA00123456.
Meanwhile, the network interface card of the destination computer is designed to continually monitor incoming packets over the network. When the network interface card detects an incoming packet containing its destination address, the network interface card will determine that it is the intended recipient of the packet, and will forward information content of the packet to the destination computer""s core, thereby completing the communications link.
In normal operations, in which both the source computer and the destination computer are operating in full power mode, all of these address conversions occur automatically and completely invisible to the user, and the communications link is readily established between the two computers. However, efforts are now being made to extend the use of network computing to power management applications, in which one or more of the computers may be operating in a low power mode. In particular, there is increasing demand for power management systems that minimize the energy consumption of computer systems, yet still allow the possibility for receiving remote communications from other computers via a network. These power management systems must provide a mechanism for remotely xe2x80x9cwakingxe2x80x9d a computer system from a low power mode to permit the computer system to receive network communications.
Generally stated, xe2x80x9cpower managementxe2x80x9d refers to a computer system""s ability to conserve or otherwise manage the power that it consumes. Although power management concerns were originally focused on battery-powered portable computers, these concerns now extend to AC-powered xe2x80x9cdesktopxe2x80x9d computer systems as well. In particular, government initiatives encourage computer manufacturers to develop energy-efficient computers.
Power management techniques include the ability to dynamically power down a computer or certain components within a computer when they are not in use, thereby conserving energy. A computer in this condition is referred to herein as being in a xe2x80x9cpower downxe2x80x9d state. Power is then restored to the computer or components when they are required for use. This process is often referred to as xe2x80x9cwakingxe2x80x9d the computer.
There are many ways in which a computer may exist in the power down state. Examples include hard off (power is disconnected), soft off (power is supplied only to components which monitor activity external to the system), hibernated power state (contents of memory are stored on disk and current state of computer is preserved while power consumption is reduced to a minimum level), suspend mode (all central processor activities are halted, but power to memory is maintained and dynamic RAM is refreshed), and sleep mode (the clock signal is reduced or halted to some or all of the system components during periods of inactivity). The sleep and suspend modes may each be invoked at various levels, depending on the particular implementation of these modes, and recovery from these modes is implementation specific.
In an effort to standardize power management using a computer""s operating system, Intel, Microsoft, and Toshiba have collaborated to produce the Advanced Configuration and Power Interface (ACPI) specification. Under ACPI, a computer system can be placed in one of five graduated reduced-power system states, which do not necessarily correspond (in functionality or in name) to the power down modes recited above. Nevertheless, these states also represent power down states of a computer.
When a computer is in a power down state, it may be configured to awaken if activity is detected, e.g. movement of a mouse or actuation of a power switch. The source of the triggering activity may come from a local mechanism (i.e. a switch or sensor of any kind such as a power switch, a reset switch, a pressable key, a pressure sensor, a mouse, a joystick, a touch pad, a microphone, or a motion sensor), or the trigger source may be remote. The ability to remotely awaken a computer increases its usability and maintainability. For example, a user can remotely retrieve files even when the computer was powered down, and a system administrator can perform system maintenance after hours without needing to physically visit each computer.
There are several existing power management systems which are designed to operate in a network environment. In one system for waking a computer from a local area network, a remote wake frame known as a xe2x80x9cmagic packetxe2x80x9d is defined that includes the destination address repeated 16 times consecutively anywhere within the packet. While the computer is in the power down state, its network interface card continually monitors all incoming message packets for one that has its destination address repeated 16 times. When the network interface card detects an incoming packet with this address sequence, the network interface card asserts a signal to wake the rest of the computer and then start the operating system. The operating system may optionally be started up in an xe2x80x9cadministration modexe2x80x9d with restricted access (e.g. the user may be locked out for the duration of a maintenance task).
In another prior system for waking a computer from a local area network, the computer""s network interface card is provided with a list of packets stored in memory. When an incoming packet of information is transmitted to a computer in the power down state, the network interface card compares the incoming packet to the list of packets that it has stored in memory. If the incoming packet matches one of the packets in the list of packets, then a signal is issued to wake the computer. Otherwise, the incoming packet is discarded and the sleeping computer is not awakened.
Typically, upon receiving a xe2x80x9cwake-upxe2x80x9d packet, the network interface card asserts an interrupt or reset signal to awaken the computer. Depending on the power down state and the specific power management implementation, the computer responds by restarting a clock signal, restoring a memory state, performing an initialization process, or otherwise returning the system to a full power mode.
Security is an important consideration in computer networks, and the prior network-aware power management systems do not include any provisions for security. Computers in a power down state may prove to be vulnerable links in certain computer networks. For example, some proposed computer systems will respond to wake-up packets by retrieving their initial executable programs via the network. Skilled saboteurs may be able to use this system feature to gain access to a network or to simply cause mischief. Indeed, simply broadcasting wake-up packets in many existing networks can frustrate a company""s attempts to reduce power consumption.
Consequently, it is desirable for a computer system in a power down state to be able to discriminate between authorized wake-up packets and unauthorized wake-up packets.
Accordingly, there is provided herein a secure system and method for remotely waking a host computer from a power down state. In one embodiment, a network interface card receives incoming data packets via a network connector. A control module is coupled to the network connector and is configured to search the incoming packets for a wake-up pattern. The control module also verifies that the packet""s destination address matches the destination address of the network interface card. If the destination addresses match and a wake-up pattern is found, the control module decrypts an encrypted value from the incoming packet and compares the result to an expected value. A successful comparison causes the control module to assert a signal to wake up the host computer. Preferably, a standard public/private key pair encryption scheme is used, and the source of the data packet encrypts the expected value with a private key, All computers which may receive wake-up packets are provided with a public key with which to decrypt values contained in a security field of any wake-up packets. A successful decryption serves to certify that the wake-up packet was transmitted from an authorized source. For added security, the expected value and public/private keys may be changed on a regular basis, or even every time a valid wake-up packet is received. The new value may be provided in the wake-up packet, to be stored by the network card for the next use.
The present invention also contemplates a method which comprises: (i) receiving a data packet from a network; (ii) comparing a destination address of the data packet to a destination address of a network interface card; (iii) determining if a wake-up pattern is present in the data packet; (iv) decrypting an encrypted value from the data packet to obtain a decrypted value; and (v) asserting a wake-up signal if the destination addresses match, a wake-up pattern is present, and the decrypted value matches an expected value. Preferably, the encrypted value is produced according to a standard public key/private key encryption scheme.

Secure system for remotely waking a computer in a power-down state

Compaq Information Technologies Group, L.P.


A process task management system is provided to be used within an operating system environment. The system comprises an executing processes module containing a list of processes currently executing in the operating system environment. A status attribute is included for each process in the list, which represents an execution state of the process and is viewable by a user. A process state checking module is configured to check the execution state of each process when the process is busy, and to set the status attribute for each process to inform the user whether the execution state of the process is busy and performing processing activity.

When a user runs an application or program on a computer, the user is actually requesting the operating system to load and run one or more processes associated with that application. For example, an application can have a primary process that is loaded initially and additional auxiliary processes which may be loaded as needed.
From the point that applications load, the user expects to be able to constantly and quickly interact with each application whenever they desire. This constant interaction is frequently possible when just a small amount of processing is performed between user events, such as a button click or a menu item request in the application. For example, a word processor performs most of its processing in small chunks and the user is able to access the user interface seemingly instantaneously.
Other applications may not be available to the user for a certain period after the user has requested a complex or time-consuming operation. The period may be a few seconds or sometimes longer. Some applications and processes are able to present the user with a screen that notifies a user of the status of their request. Unfortunately, many processes cannot provide this status. This is especially true where the process running on the user's side has requested information from a process running on a remote server or database. In these situations, the process will make its request and then appear to freeze as the request is performed remotely from the local machine.
Even when an application presents a screen to the user and tells the user that the application or process is busy performing operations, the user may not know whether the service request is being processed or whether the application has crashed. This is especially true for an application that is not able to present a user with a progress screen. The user interface in such a situation will appear to be frozen but the application will actually be performing normal processing behind the scenes. Either the user must be patient in this situation or the user can decide to try to terminate the application or process. To terminate an application's processes, the user opens the operating system's task manager and requests that the specific processes terminate immediately.
If the user decides to terminate a process, this can be a problem in many situations because the process is not allowed to terminate normally when a user shutdown is initiated. This means that the normal cleanup and shutdown functions cannot be activated. Of course, there are legitimate situations where processes should be shutdown. A process should be shutdown when it has crashed or there has been a process or system malfunction. In these cases, the process should be stopped and restarted.
If the process is still working, then the user generally does not want to shut down the process because at some point the process will complete the task that the user has requested. Shutting down a process prematurely can cause serious problems for the process or the entire system. Shutting down the process prematurely can cause corruption in the process itself and cause corruption to other processes or a service from which the original process has requested information. One situation where this might happen is a process that is requesting information from or trying to write to a database. If the process is writing the information to the database and then the process is prematurely terminated, the database may be corrupted and/or left in a partially completed state.

System and method for process management

Hewlett-Packard Development Company, L.P.


Bandwidth allocation management includes determining current available bandwidth of a network within which a computer system is operating. The bandwidth allocation management also includes using the current available bandwidth and applied feature delivery settings to determine an adjustment in feature delivery to the computer system. At least a portion of the feature delivery settings is specified by an end user of the computer system.

The present invention relates to computer networking, and more specifically, to adaptive, configurable feature delivery in a computer network environment.
Social networking sites such as Facebook® and LinkedIn®, goal-oriented sites such as Match.com® and eDiets.com®, as well as internal business networks (e.g., Intranet portals), provide the ability for individuals to associate and/or collaborate with other individuals over a network. These, and other, networking sites typically involve a community of users who share some common purpose (e.g., business/professional, social, and/or goal-oriented).
As technology advances, e.g., with respect to rich multi-media applications, competition among available resources (e.g., bandwidth and memory) often results. Consequently, there is becoming a greater need to manage and (when possible) conserve these finite resources. As consumers demand more and more content, higher definition services, interactive services, and data services, existing network infrastructures have become concerned with the increasing burden of providing adequate bandwidth to meet these demands.
During an active Internet browsing session, packets associated with various content sources are transmitted/streamed to an end user device. These packets are assigned some priority value which, in turn, determines the amount of bandwidth to be allocated to these packets. Video/audio packets consume substantial amounts of bandwidth when a user requests a page/resource that has video effects embedded therein. In order to provide maximum performance, these types of packets are typically assigned a greater priority.
Oftentimes, a computer system runs multiple applications that share available system resources, such as memory and bandwidth. When a number of full-featured applications are simultaneously running, the overall system performance may be hampered as a result of the finite amount of available resources. In such cases, even basic operations make take more time than desired to complete, thereby wasting the system user's valuable time.
Many applications provide much of their functionality as small plug-ins, which get loaded at runtime or which may be activated only when some action is taken. Even if the plug-in is activated upon the occurrence of some action, a corresponding user interface and underlying framework supporting the plug-in still consumes a considerable amount of resources and which makes the application 'heavy.'
An always-on widget (e.g., instant messenger) is one example of wasted bandwidth. For example, an always-on chat widget with video chat feature receives content even if the user will be not be watching it. When the widget remains fully equipped with all features despite its lack of use, it unnecessarily consumes bandwidth. While some sites offer a light version for users with low bandwidth Internet access, this solution offers no user discretion over what features will go into the light version. In addition, this solution does not provide for the enablement or disablement of features based upon the current needs of the system user.

International Business Machines Corporation


An electric drive (1) with a motor housing (16), a bearing plate (4), an electrically insulating brush holder plate (3) with formed-on plug housing (11), a printed circuit board (13) with plug lugs 14 which project through plug recesses of the brush holder plate (3) into the plug housing (11), where the brush holder plate (3) serves as a carrier for the printed circuit board (13). The objective of the invention is to present an electric drive which can be securely mounted and handled in an economical manner in which many electric and electronic components are accommodated in a space-saving manner and which has good interference suppression characteristics. This objective is realized according to the invention by the fact that a sensor (23) is mechanically and electrically connected to the printed circuit board (13), the bearing plate (4) is electrically conductive, the printed circuit board (13) comprises tracks on both sides, the sensor (23) is held in a recess (25) of the printed circuit board (13), and a ground track (27) of the printed circuit board (13) faces the bearing plate (4) and is in direct electrical contact with it and mechanically fastened to it.

1. Field of the Invention
The invention relates to an electric drive for a motor, in general, and to an electric drive with a motor housing, a bearing plate, an electrically insulating brush holder plate with formed-on plug housing a printed circuit board with plug lugs which project through plug recesses of the brush holder plate into the plug housing, where the brush holder plate serves as a carrier for the printed circuit board, in particular.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
German Patent Application No. DE 43 15 404 A1 shows a generic electric drive in which a bearing plate cannot make contact with a printed circuit board found in the generic electric drive.

Electric drive with sensor mounted on printed circuit board


A process for removal of dissolved H.sub.2 S from condensed geothermal steam that includes the steps of cooling and oxygenating the sour steam condensate by contacting the sour condensate with air in a cooling tower; collecting the oxygenated condensate in a cooling tower collection basin and initially adding a polyvalent metal chelate catalyst, e.g., iron chelate catalyst solution, to the sour condensate at a very low concentration, e.g., about 0.1 ppm to about 10 ppm, preferably about 0.5 ppm to about 1 ppm by weight, and periodically or continuously adding, to the solution, a chelating agent for the polyvalent metal to account for chelon degradation to maintain active polyvalent metal chelate solution at a concentration of about 0.1 ppm to about 10 ppm, preferably about 0.5 ppm to about 1 ppm by weight. The dissolved H.sub.2 S is removed, by oxidation to sulfur, without the addition of polyvalent metal, e.g., iron, to the solution, and without blowdown of the condensate circulated through the cooling tower.

Industrial waste water containing dissolved hydrogen sulfide presents a significant pollution problem because of its high toxicity and unpleasant odor, even at low concentrations. The treatment of such waste water is necessary before discharging it to the environment to reduce the hydrogen sulfide content to acceptable levels. The present invention provides a simple and effective method of removing hydrogen sulfide from such waste water streams by the initial addition of a chelated heavy metal catalyst, e.g., iron chelate solution, and, thereafter, adding mostly chelate solution, to replace degraded chelon, while retaining nearly all of the heavy metal in solution (about 90% to about 100%, preferably 95% to 100% by weight).
Typical sour water streams are those produced in oil refineries by water washing of sour liquid hydrocarbons and various cooler and condenser surfaces. Condensation of geothermal steam also produces sour water which requires treatment. Although the present invention may be used for the treatment of any sour water stream regardless of its source, the invention is of particular significance for treating geothermal condensates.
In a geothermal power plant, geothermal steam is used to power a steam turbine which is connected to an electric power generator. The exhaust steam from the turbine is supplied to a condenser, and the resultant steam condensate is removed for reuse or discard. In prior art processes about 1/3 of the condensate is discarded, usually after cooling tower treatment. Geothermal steam contains dissolved hydrogen sulfide in amounts which may range, for example, from as low as about 5 ppm to as high as about 1600 ppm and typically may average about 150 ppm to 250 ppm. Dependent upon the type of condenser and its efficiency, a significant percentage, e.g., as much as 80%, of the hydrogen sulfide in the geothermal steam will end up as dissolved hydrogen sulfide in the condensate. This sour water stream must be treated to remove hydrogen sulfide in order to avoid environmental pollution.
U.S. Pat. No. 4,076,621 discloses a process for removing hydrogen sulfide from sour water by air stripping the dissolved hydrogen sulfide from the sour water and then scrubbing the air stream with an aqueous solution of chelated iron. U.S. Pat. Nos. 4,414,817; 4,451,442; and 4,468,929 disclose processes for removing hydrogen sulfide from geothermal steam or condensate using an aqueous solution containing at least the stoichiometric amount of a chelated polyvalent metal. U.S. Pat. No. 4,363,215 discloses a process for removing hydrogen sulfide from geothermal steam condensate using hydrogen peroxide and an iron chelate catalyst. U.S. Pat. Nos. 4,614,644 and 4,629,608 disclose processes for removing hydrogen sulfide from geothermal steam using a chelated iron solution and a cationic polymeric catalyst. U.S. Pat. Nos. 4,451,442; 4,468,929; and 5,057,292 disclose processes for removing hydrogen sulfide from geothermal steam condensate including loss of iron chelate catalyst that is replaced at the same rate of loss.
The known sour water treatment processes that rely on the use of chelated polyvalent metal solutions, e.g. chelated iron, are complex and have disadvantages, such as excessive consumption or discard of expensive polyvalent metal and chelating agent.
One method of treating geothermal steam condensate, currently being practiced, is shown in FIG. 1. In accordance with the prior art method shown in FIG. 1, sour condensate is processed by directing about 2/3 of the condensate to the top of a cooling tower, where most of the condensate is cooled and evaporated, and the remaining about 1/3 of the sour condensate is directed to deep well disposal, reinjecting the 1/3 of the condensate into the geological formation near its origin. Sufficient sour condensate is directed into the cooling tower to provide a slight excess of condensate that is received in a cooling tower collection tray or basin to ensure that sufficient condensate is available for recycle to the steam condenser. The excess condensate received in the cooling tower collection basin is directed to deep well disposal together with the portion of the condensate that is not directed to the cooling tower.
Polyvalent metal chelate catalyst solution, e.g., iron chelate solution, is required for removal of dissolved hydrogen sulfide contained in the sour steam condensate and the polyvalent metal chelate solution lost to deep well disposal can be added to the sour condensate either prior to the condensate entering the cooling tower, or in the cooling tower collection basin, as shown in FIG. 1.
In accordance with the present invention, at least 90% by weight of the polyvalent metal is retained for continuous recirculation, without more than 10%, and preferably less than 5% by weight loss of sour condensate and polyvalent metal to disposal, requiring only the addition of chelon to the process due to chelon degradation, without substantial losses of polyvalent metal. Some blowdown or removal of water and polyvalent metal from the cooling tower basin may be required, up to about 10% by weight, and preferably 0-5% discard of condensate, to limit the concentration of salts in the water recirculated to the condenser. It is understood that this blowdown (0-10%, preferably 0-5% of the condensate) will contain a small amount of fully chelated iron, which must be replaced by the addition of a small amount of fully chelated iron to the system. However, because the water lost by evaporation is replaced by condensation of steam, there should be little or no salts entering the system and it should be possible to operate with very little (0-10%, preferably 0-5%, and ideally 1-3%, e.g. 2%) blowdown.

Removal of hydrogen sulfide from sour water without loss of heavy metal


There is provided a circuit arrangement for switching a current on and off without overcurrent. The circuit arrangement includes a current source, a load associated with the current source, a switching transistor for switching the current source on and off, where the switching transistor has a parasitic capacitance between a control electrode and a first output electrode, and a shorting device between the control electrode and the first output electrode of the switching transistor for switching off the current source. The current can be used, for example, to drive a laser diode.

Circuit arrangements for switching a current driving a load on and off are known.
FIG. 1 shows such a circuit arrangement, which uses a transistor 20′ as a current source or current sink. The control electrode of the transistor 20′ is connected to a DC voltage source 80′. The current source 20′ is connected in series with a load 40′, for example with a laser diode. A switching transistor 50′, which is likewise connected in series with the current source 20′, is used as a switch for the current source. The switching transistor 50′, which is in the form of a field-effect transistor, for example, is connected by means of its gate electrode 51′ to a driving device which comprises the transistors 75′ and 70′, for example. The input 1 of the driving device 70′, 75′ has a switch-on/switch-off signal P applied to it, as illustrated in FIG. 2, for example. Between the gate 51′ and the drain electrode 52′ of the switching transistor 50′ there is a manufacture-dependent parasitic capacitance 60′, which is also known as the Miller capacitance. As will be explained later, this parasitic capacitance is the cause of overcurrents that are brought about when the current source 20′ is switched off. The gate/source voltage GS of the switching transistor 50′ controls the state of the switching transistor. If this gate/source voltage GS is lower than the threshold voltage of the switching transistor 50′, the current IL is interrupted by the switching transistor 50′. The gate/source voltage GS is S controlled by means of the driving device 70′, 75′. However, when the switching transistor 50′ and hence the current source 20′ are disconnected, an overcurrent, also called a current spike, is produced which has its origins in the parasitic capacitance 60′ of the switching transistor 50′. This is because a falling edge of the gate/source voltage GS on the switching transistor 50′ (the profile of said gate/source voltage being shown in FIG. 4) causes the parasitic capacitance 60′ to transfer the sudden voltage change on the control electrode 51′ to the output electrode 52′ of the switching transistor 50′ and to drive the transistor 20′ at a higher level. This causes an overcurrent through the load 40′, as shown in FIG. 3 at the time ta. The overcurrent flows until the parasitic capacitance's charge has been reversed. The time ta characterizes the time at which the switch-off signal is applied to the input 1 of the driving device 70′, 75′. In the case of certain applications, such current spikes can result in the load 40′ being destroyed, as can be the case with a laser diode, for example.

Circuit arrangement for switching a current of and off without the occurrence of overcurrent


An interface for mass spectrometers. The interface uses non coaxial sampling pathways of the analyte ion beam prior to entering the entrance of a mass spectrometer for decreasing chemical background, and can be done in such a way as to permit multiple sprayers, increasing sample throughput and sensitivity for LC/MS (liquid chromatography/MS). The interface includes an ion source having an exit from which a beam of analyte ions are emitted, a curtain plate and an aperture in the curtain plate member, an orifice plate having an orifice therein. The orifice plate is being spaced from the curtain plate member defining a flow passageway therebetween, and the aperture in the orifice plate is aligned with a sample entrance to a first vacuum stage of a mass spectrometer maintained substantially lower than atmospheric pressure. The aperture in the curtain plate member is non coaxially aligned with the orifice in the orifice plate and the interface includes a gas flow mechanism for directing a counter flow gas into the flow passageway.

Mass spectrometry (MS) is a well-known technique for obtaining a molecular weight and structural information on chemical compounds. According to mass spectrometry, molecules may be "weighed" by ionizing the molecules and measuring the response of their trajectories in a vacuum to electric and magnetic fields. Ions are "weighed" according to their mass-to-charge (m/z) values.
Atmospheric pressure ion sources (API) have become increasingly important as a means for generating ions used in mass spectrometers. Some common atmospheric pressure ion sources include Electrospray or nebulization assisted Electrospray (ES), Atmospheric Pressure Chemical Ionization (APCI), and Matrix Assisted Laser Desorption Ionization (MALDI). These ion sources produce charged particles, such as protonated molecular ions or adduct, from analyte species in solution or solid form, in a region which is approximately at atmospheric pressure.
Conventionally a single type source is used one at a time. However, it is sometimes preferable to use multiple ion sources simultaneously, for example to increase the number of samples analyzed per unit time, also know as throughput. Also, some analyte samples respond well to one approach, such as ESI, and others to another approach such as APCI, and it is desirable to provide a simultaneous approach that is optimal for the formation of charged species.
Mass spectrometers generally operate in a vacuum maintained between 10−4 to 10−10 torr depending on the mass analyzer type. Thus once created, the charged particles must be transported into vacuum for mass analysis. A portion of the ions created in the API sources are entrained in the bath gas within the API source chamber and are swept into vacuum along with a carrier gas through an orifice into vacuum. One challenging aspect for high sensitivity lies in efficient transportation of the desired charged ions from atmosphere to the vacuum.
The API sources are advantageous because they provide a gentle means for charging molecules without inducing fragmentation. They also provide ease of use because the sample can be introduced at atmosphere.
API sources have a disadvantage of producing high chemical background and relatively low sensitivity. This is believed to be caused by sampling of impurites attached to the analyte ion (for example, cluster molecules, atoms or ions, or other undesired adduct ions), caused by incomplete desolvation during the API process. In this way, along with desolvated ions, many such droplets of varying diameters can enter into the mass spectrometer and consequently produce a large level of chemical noise across the entire mass range. Additionally incompletely vaporized droplets linger near the sampling orifice.
These problems can be most severe for high liquid sample flow rates, that typically range from 0.2 to 2.0 mL/min. Efficient Electrospray Ionization (ESI) at high flow rate requires sufficient heat for desolvation and a method to deter large clusters from entering the vacuum chamber while enhancing the ion capture. High flow rate analyses are important to industries that have large throughput requirements (such as drug development today, and in the future, protein analysis) because such flow rates are presently necessary for the High pressure Liquid Chromotography (HPLC) techniques performed prior to mass spectrometric analyisis. For most modern applications of ESI and APCI, liquid samples are passed through the source at high flow rates.
To reduce the problem of incomplete desolvation, heated gases are commonly employed to vaporize with a flow direction opposite, or counter, to sprayed droplets in order to desolvate ions at atmospheric pressure. Since the heated gases remove much of the solvent vapor from the stream of gas before being drawn into the vacuum chamber, this technique increases the concentration of ions of interest in the vacuum chamber.
For example, U.S. Pat. No. 4,023,398 teaches a technique whereby ions pass through an orifice into a vacuum chamber, while a gas curtain upstream from the orifice reduces transmission of solvent vapor into the vacuum chamber. The gas is heated to hasten evaporation of the solvent from the droplets, thereby producing desolvated ions at substantially atmospheric pressure. U.S. Pat. No. 4,531,056 teaches a similar technique, whereby an inert gas is introduced into the electrospray chamber in a direction opposite to a flow from the capillary. The electrospray chamber remains at or slightly greater than atmospheric pressure. Ions of interest are produced within the electrospray chamber, and the inert gas flow substantially reduces the concentration of solvent vapor that enters the analyzer. U.S. Pat. Nos. 4,842,701and 4,885,076 disclose a system that combines capillary zone electrophoresis with electrospray for gas analysis of an analyte mixture. Again, the electrospray occurs at atmospheric pressure, and a heated countercurrent gas flow technique is used to desolvate the spray droplets.
While the counter flowing gas concept described above results in reasonable sensitivity, it is typically incorporated using a largely coaxial geometry between the sprayer and the mass spectrometer. This substantially decreases the ruggedness of the interface between the electrospray and the mass spectrometer, since a portion of the spray can still enter the mass spectrometer. It also reduces the sensitivity since the desolvation time spent in the flow is small.
Now, importantly, it is often useful and desirable to operate with multiple ion sources substantially simultaneously, for example using two or more ESI sources, or an APCI and ESI source, while also reducing the chemical noise and maintaining the simplicity of the atmospheric pressure source. This permits higher throughput or sensitivity (improved signal-to-noise) of sample than is possible with a single ion source, as well as other useful functions such as providing the possibility of on-the-fly calibration. Thus signal-to-noise (sensitivity) and functionality are enhanced,
Prior art interfaces exist that contain multiple sprayers. However they are complex devices, requiring moving parts such as rotating cylinders and blocking apertures to select the appropriate sprayer, or utilizing multiple apertures to a vacuum system, thereby increasing vacuum load, increasing cost or reducing sensitivity. For example, U.S. Pat. No. 6,784,422 teaches approaches for multiple sprayers using multiple sampling apertures directed into the low pressure of the mass spectrometer. It also teaches various approaches to blocking these apertures, and switching the ion beams near these apertures. This approach disadvantageously increases vacuum load, increasing cost or reducing sensitivity.
It is therefore desirable to provide an improved mass spectrometer interface for atmospheric pressure ionization sources suitable for multiple sources having improved sensitivity, enhanced stability and ruggedness and more functionality than prior interfaces, with substantially reduced complexity and cost, and reduced or eliminated source-to-source interference.

High sensitivity mass spectrometer interface for multiple ion sources


A hydrogen gas separator fixing structure includes a gas separator having a support and a membrane provided on at least one surface of the support, which membrane contains a first metal capable of separating hydrogen gas from a hydrogen-containing gas, a metal flange connected to at least one open end of the gas separator, a bonding layer containing a second metal, provided at the portion at which the gas separator and the metal flange are connected to each other and on the surface of the gas separation membrane side of the portion, a packing provided on the bonding layer, and a ring-shaped metal member capable of fixing the packing by pressing, provided so that at least part thereof is in contact with the bonding layer, wherein the bonding layer is provided by a heat treatment conducted at a temperature lower than the melting point of the second metal.

The present invention relates to a hydrogen gas separator fixing structure and a hydrogen gas separating device using the same.
Hydrogen gas is used in a large amount as a basic raw material gas in petrochemical industry and also is expected highly as a clean energy source. In order to separate only a particular gas component from a mixed gas of multiple components, there has been known a separation method using an organic or inorganic, gas separation membrane, i.e. a membrane separation method. As the membrane used for hydrogen separation, there are known an organic polymer membrane such as polyimide, polysulfone or the like, a ceramic membrane such as silica or the like, and an inorganic compound membrane such as palladium, palladium alloy or the like. A palladium membrane or a palladium alloy membrane, in particular, is heat-resistant and further makes it possible to obtain hydrogen of extremely high purity.
Palladium or palladium alloy can absorb hydrogen alone, making possible selective separation of hydrogen. Palladium or palladium alloy is ordinarily used in the form of a thin membrane of about 1 to 20 μm in thickness, coated on a porous support of ceramic or the like, in order to achieve a high hydrogen permeation rate.
As to related conventional techniques, there are disclosed gas separators comprising a porous substrate and a gas separation membrane composed of palladium or palladium alloy, formed on one surface of the porous substrate (see, for example, Patent Documents 1 and 2). The porous substrate used therein is composed of glass, or a ceramic of aluminum oxide or the like. The gas separation membrane is formed on the porous substrate because no sufficient mechanical strength is obtained only with the gas separation membrane.
A gas separating device incorporating therein a gas separator such as mentioned above has such a structure that a gas separator is placed in a metal-made vessel, wherein a gas to be separated is introduced from one side of the gas separator, only a particular gas (hydrogen) permeates the gas separator, and purified gas (hydrogen) is taken out from the other side of the gas separator. Therefore, it is necessary that the gas to be treated side and the purified gas side are separated gas-tightly and the gas separator is gas-tightly connected to the purified gas outlet of metal-made vessel. Hence, it is important that the gas to be separated causes no leakage from the connection portion between the gas separator and the metal flange connecting to the purified gas outlet, to the purified gas side. Meanwhile, in order to efficiently separate hydrogen gas using the gas separator, the permeation rate of hydrogen atoms in gas separation membrane needs to be high; therefore, separation at a high temperature (300° or higher, preferably 500° or higher) and a high pressure (5 to 20 atm.) is advantageous. In this case, the gas tightness and durability of the connection part between the gas separator and the metal flange are important. That is, there is required such durability as to be able to sufficiently maintain the gas tightness under which the gas to be separated causes no leakage from the connection part between the gas separator and the metal flange to the purified gas side even under conditions of high temperature and high pressure.
In order to inhibit leakage of gas under the above conditions, it is generally conducted to braze the gas separator and the metal flange with a brazing material or the like (see, for example, Patent Document 3). It is also conducted to use an O-ring to secure the gas tightness between the gas separator and the metal flange therefor when the gas-treating temperature is 250° C. or lower.
In the above-mentioned brazing of the gas separator and the metal flange, however, there occur in some cases problems that the high temperature of brazing and resultant thermal stress causes the breakage of the porous substrate constituting the gas separator, or the load of heat cycle invites a reduction in gas tightness between the gas separator and the metal flange. Further, it is necessary to control the clearance between the gas separator and the metal flange therefor strictly and connect them in such a controlled state. Furthermore, the high brazing temperature incur in some cases, problems such as the breakage due to melting and the strain generation due to heat stress, of the gas separation membrane constituting the gas separator. In using the O-ring, it has been substantially difficult to maintain sufficient gas tightness when the temperature of gas treatment is higher than 250° C., and the there has been a limitation in applicable temperature range.
In order to solve the above-mentioned problems, there are disclosed a gas separator fixing structure wherein a gas separator and a metal flange are sealed with a gland packing (see, for example, Patent Document 4). Since this gas separator fixing structure employs no brazing, there hardly occurs a problem of breakage of substrate due to thermal stress; however, gas-tight brazing completely free from leakage is difficult to achieve and a countermeasure for leakage from connection portion is necessary. In applications where separation of higher-purity gas is required, there has been necessary even higher gas tightness between gas separator and metal flange therefor.                Patent Document 1: JP-A-1987-273030        Patent Document 2: JP-A-1988-171617        Patent Document 3: JP No. 3305484        Patent Document 4: JP-A-2003-126662

Hydrogen gas separator fixing structure and hydrogen gas separating device using the same


The present invention relates to the field of oligonucleotide conjugates and to methods of synthesis thereof. In the present method a low-water content solvent environment allows a more efficient conjugation, reducing the amount of conjugate moiety needed and increasing the conjugation reaction speed.

Recently there has been considerable focus in the conjugation of oligonucleotides with non-nucleotide moieties which add additional functionality to the oligonucleotide, for example, enabling targeting of therapeutic oligonucleotides to specific organs and tissues in vivo. For targeting to liver hepatocytes trivalent GalNAc conjugation moieties capable of binding to asialoglycoprotein receptors have been found to allow for vastly reduced dosages whilst delivering effective therapeutic action, see for example WO2014/118267. WO 2013/033230 also describes a variety of oligonucleotide conjugates including antibodies, carbohydrates, cholesterol, insulin, PEG, transferrin and vitamins. The manufacture of oligonucleotide conjugates is therefore of major importance, particularly when considering the increased costs of manufacture of the conjugate group and the additional process steps in conjugation.
Milesi et al., Methods in Enzymology (1999) 313, pp 164-173, reports on the synthesis of oligonucleotide conjugates in anhydrous dimethyl sulfoxide. The procedure used by Milesi at al. uses triethylammonium salt to solublise an 10 bp DNA oligonucleotide in DMSO, prior to conjugation to a lipophilic 5′minor groove binding conjugate, and is recommended for use with lipophilic and hydrostatically unstable groups. According to Milesi et al., 2.5 molar equivalents of conjugate group were used as compared to the oligonucleotide, and typically up to 20 molar equivalents of the conjugate group are used.

This patent is subject to a terminal disclaimer.


A guidance system of an industrial process captures process parameter data that is correlated with a human-machine interface (HMI) in order to learn how an experienced operator selects visualizations of key performance indicators (KPI) in order to take a corrective action to address an abnormal or non-optimal performance condition. Such solution learning can be invoked to recognize onset of another similar occurrence and responding by suggesting visualizations utilized by the experienced operator to diagnose the problem. Analytics can further determine which visualizations provided useful information relative to the problem. In addition, the corrective action can be suggested or automatically implemented.

Industrial controllers are special-purpose computers utilized for controlling industrial processes, manufacturing equipment, and other factory automation, such as data collection or networked systems. One type of industrial controller at the core of an industrial control system is a logic processor such as a programmable logic controller (PLC) or personal computer (PC) based controller. Programmable logic controllers for instance, are programmed by systems designers to operate manufacturing processes via user-designed logic programs or user programs. The user programs are stored in memory and generally executed by the PLC in a sequential manner although instruction jumping, looping and interrupt routines, for example, are also common. Associated with the user program are a plurality of memory elements or variables that provide dynamics to PLC operations and programs.
Connected to the PLC are input/output (I/O) devices. I/O devices provide connection to the PLC for both automated data collection devices such as limit switches, photoeyes, load cells, thermocouples, etc. and manual data collection devices such as keypads, keyboards, pushbuttons, etc. Differences in PLCs are typically dependent on number of I/O they can process, amount of memory, number and type instructions and speed of the PLC central processing unit (CPU).
Another type of industrial controller at the core of an industrial control system is the process controller of a distributed control system (DCS). The process controller is typically programmed by a control engineer for continuous process control such as an oil refinery or a bulk chemical manufacturing plant. A control engineer typically configures control elements such as proportional-integral-derivative (PID) control loops to continuously sample the I/O data, known as the process variable, from the process, compare the process variable to a configured set point and output an error signal, proportional to the difference between the set point and the process variable, to the control device. The control device then adjusts the element controlling the process property, such as a valve in a pipe for flow control or a heating element in a distillation column for temperature control, in an attempt to minimize the error signal. As the DCS name implies, many process controllers are distributed around the process and are communicatively coupled to each other forming the overall control system.
Connected to the process controller are similar types of I/O devices as connected to the PLC and additionally, intelligent I/O devices more common to the process control industry. These intelligent devices have embedded processors capable of performing further calculations or linearization of the I/O data before transmission to the process controller.
A visualization system is generally connected to the industrial controller to provide a human-friendly view into the process instrumented for monitoring or control. The user of a visualization system configures one or more graphical displays representing some aspect of the process the industrial controller is controlling or monitoring. The graphical displays each contain a user configured number of data values collected from the I/O connected to the industrial controller and considered by the user as relevant to the particular graphical display or process area of interest. Other data points may be configured strictly for archival purposes or to generate reports related to interests such as production, downtime, operator efficiency, raw material usage, etc.
Automating control and human-machine interface (HMI) to achieve efficiency, quality, safety, performance, etc. generally requires expertise to be embodied in a model. Relationships between certain data parameters are determined in order to prompt an operator or to facilitate automatic control events. Often such models benefit from tendencies for setting up identical processing lines (e.g., batch, continuous, or discrete). Thus, the investment in such models can be realized across sites of an enterprise.
However, generally such models, if in existence at all, tend to be an incomplete solution. Production lines can be customized for particular applications. Substituted hardware can perform similarly, but not identically, to that which was modeled. Ambient parameters (e.g., humidity, temperature, etc.) can vary from location to location and from time to time within a facility. Materials input into a process can vary from batch to batch or from different suppliers. Further, relationships between certain parameters can go unappreciated during the development of a process model. Although increasingly data is available from ubiquitous integrated devices and sensors, the large amount of data does not necessarily enhance understanding of why an industrial process is departing from a desired optimum condition.
Compensating to an extent for the limitations in automated sensing and control, operators can become exceedingly skilled in detecting aberrations in an industrial process, perhaps accessing data from the HMI in an unexpected way in order to locate indications of where the problem originates. Other operators, though, such as with less experience and on another shift, can lack the intuition in order to identify such solutions.

Analytical generator of key performance indicators for pivoting on metrics for comprehensive visualizations


In one embodiment, the present invention includes a method for receiving data corresponding to a portion of an incoming radio frequency (RF) spectrum, determining a set of estimates including one or more pairs of a channel frequency estimate and a symbol rate estimate from the data via a linear spectrum analysis, and determining a refined set of estimates from the set of estimates via at least one non-linear spectrum analysis.

Receivers are used in many applications to receive incoming radio frequency (RF) signals and convert them to baseband signals for desired processing. Various such receivers exist including cellular receivers, radio receivers, satellite receivers such as television satellite receivers, among many others.
A receiver is typically coupled to receive incoming RF signals from an antenna and process the signals in various stages, including amplification stages, filtering stages, downconversion stages and the like. In a satellite system, such as a direct video broadcasting (DVB) system, an RF spectrum of a very wide band, e.g., approximately 1.3 gigahertz (GHz), includes many individual channels carrying programming. Typically, these channels are separated by some predetermined spacing, and the bandwidth of given channels can vary. A receiver will include a list of available channels within the RF spectrum, their center or carrier frequencies, and corresponding symbol rates, among other such information.
While in many countries this information remains fixed, in other countries, center frequencies and baud rates can change over time. Accordingly, a receiver can include functionality to search for and locate available channels. Such operation is typically referred to as a blind scan. A blind scan is used to establish a list of valid channels with sufficiently estimated carrier frequencies and baud rates for a given frequency band and symbol rate range. However, existing blind scan functionality is relatively inefficient and requires significant time to perform analysis of an RF spectrum, such as a satellite spectrum. This excessive time is incurred as typical blind scans exhaustively scan all possible combinations of frequency shifts and symbol rates to find every possible channel within a given frequency band and baud rate range. Such blind scans generally use a non-linear transform analysis, meaning that the original data has undergone some sort of non-linear transform, the results of which are then analyzed in the frequency domain. However, because of the presence of adjacent channels, inter-modulation products confuse the analysis, as do the effects of filtering and aliasing.
Still further, in known satellite systems when acquiring a desired channel, a dish antenna, e.g., a low noise block (LNB) antenna, is often off by a large frequency from the proper frequency for a selected channel. Such frequency errors can lead to poor performance, or even the inability to properly tune a desired channel.
Thus a need exists for improved blind scan processing, as well as a manner to improve frequency acquisition of a desired channel.


Techniques for low temperature ion implantation are disclosed. After a wafer is cooled to a temperature lower than a temperature of an environment outside of a chamber where the wafer is implanted, the cooled wafer is implanted by projecting an ion beam on the cooled wafer with a temperature adjusting apparatus being operated to cool the wafer simultaneously. Hence, heat produced by the ion beam on the implanted wafer is essentially removed by the temperature adjusting apparatus. Then, after the majority of the implanting process is performed, the temperature adjusting apparatus is turned down or off. Hence, during the residual implanting process, heat produced by the ion beam on the implanted wafer at least partially increases the temperature of the implanted wafer so that, after the ion implantation process is finished, the wafer can be moved into the environment with no, or at least less, water condensation.

1. Field of the Invention
The present invention generally relates to low temperature ion implantation, and more particularly to water condensation problems associated with low temperature ion implantation.
2. Description of the Prior Art
Low temperature ion implantation is a new branch of ion implantation. It has been discovered that a relatively low wafer temperature during ion implantation is advantageous for formation of shallow junctions, especially ultra-shallow junctions, which are becoming more and more important for continued miniaturization of semiconductor devices. Besides, the technique also has proven useful for enhancing the yield of ion implantation.
In the beginning of the current low temperature ion implantation process, a wafer is moved from an environment, such as an atmosphere or ambient environment, into an implanter, and is cooled to a temperature lower than a temperature of the environment, such as a temperature lower than the freezing point of water. Herein, the wafer can be cooled at least in a cassette outside of the implanter, in a loadlock of the implanter, in a chamber of the implanter, and so on. After the wafer is cooled, an implanting process is performed in the chamber to implant the cooled wafer. The wafer can be cooled and implanted in the same position or different positions. Moreover, during the implanting process, a temperature adjusting apparatus may be used to keep the temperature of the implanted wafer low enough, such as below the freezing point of water. In general, both the operation of the temperature adjusting apparatus and the practical implantation parameters used by the implanting process are kept constant, such that the implanted result is uniformly distributed over the implanted wafer. After that, the implanted and cooled wafer is moved out of the implanter to the environment for further semiconductor fabrication processing.
However, a serious disadvantage referred to as "water condensation" is associated with the mentioned cooling technique, due to a significant temperature difference between the low temperature ion implantation, usually performed below room temperature, such as at about −15˜−25° C. or even lower, and the temperature of the ambient environment, usually at room temperature, i.e., about 15˜25° C. Therefore, if the implanted and cooled wafer is directly moved from the chamber to the environment after the implanting process is finished, "water condensation" on the surface of the wafer induced by the temperature difference is almost unavoidable. Then, the surface of the wafer must be treated to remove the condensed water before additional semiconductor fabrication processes are performed.
One common solution is to treat the surface of the wafer after the wafer is moved out of the ion implanter and before any following semiconductor fabrication processing, such that the condensed moisture is removed prior to such processing. While this common solution addresses the damage of condensed moisture by removing it after formation, it does not prevent the formation of the condensed moisture from occurring in the first place. Hence, the cost is high, and unpredictable damage to micro-structures of wafers may be unavoidable.
Another common solution is to temporarily locate the implanted wafer inside of the ion implanter, such that the wafer is moved out of the ion implanter only after the wafer temperature has naturally been raised in a vacuum environment. As usual, a long temperature recovery time is required to allow the wafer temperature to be raised from the temperature of the implanting process to the temperature of the external environment. Clearly, this common solution solves the problem of condensed moisture by simply using the vacuum environment to prevent formation of moisture during the period of raising the wafer temperature. Unavoidably, a long temperature recovery time for naturally raising the wafer temperature inside the ion implanter reduces throughput.
Accordingly, there is a need to propose a novel and effective approach to resolve the "water condensation" problem associated with low temperature ion implantation.

Method and apparatus for low temperature ion implantation


A printing apparatus is provided and includes: a platen that supports a medium; an inkjet head provided to face the medium, the inkjet head ejecting an ink containing a charge controlling agent toward the medium by driving a drive element to land the charged ink droplet, which becomes a polarity of one of the positive polarity and the negative polarity, on the medium; and a voltage applying part that applies to at least one of the platen and the medium to have the other polarity of the positive polarity and the negative polarity.

As a printing apparatus that performs printing on a medium to be printed, for example, an inkjet type printing apparatus that ejects droplets from a head to the medium is known (see, e.g., Japanese Unexamined Patent Publication No. 2015-13455 (Patent Literature 1)). Such a printing apparatus includes, for example, a mounting stand on which the medium can be mounted, and a head that ejects droplets toward the surface of the medium while reciprocating the mounting stand in a main scanning direction.
Patent Literature 1: Japanese Unexamined Patent Publication No. 2015-13455.


A keyboard or keyboard key that has a force sensor that measures the force imparted to the key when a user presses the key or rests a finger on a key. Key embodiments may also include an actuator that excites the in order to provide feedback to the user in accordance with various feedback methods disclosed herein.

Electronic devices, such as laptops and desktop computers, may be equipped with a keyboard that provides a mechanism for entering user input. For example, a user strikes a key on the keyboard and, in response, the keyboard sends a signal to the larger system to which the keyboard is attached. Conventional keyboards typically include mechanical switches or other types of contacts that close when the key is pressed. When a key of a conventional keyboard is pressed, the key travels a substantial distance in order to close the switch or otherwise make a contact that registers a key press. Additionally, a key of a conventional keyboard typically is limited to one response that occurs when the switch or other contact is closed.
Because a conventional keyboard key typically travels a substantial distance, the space required to accommodate this travel may prevent thinner keyboards from being manufactured with conventional technology. Accordingly, in one respect, it may be desirable to have a keyboard key that does not travel a substantial distance so as to be able to produce thinner keyboards. In another respect, it may be desirable to have a keyboard key that can accommodate more than one response in a single key. These and other considerations are addressed by the following disclosure.


An assembly method and fixture for assembling a supporting disk of a motor rotor according to the invention is based on an “adjusting, and fixing” concept. A functional axis fixture and an adjusting axis fixture, which can match with each other for holding the supporting disk and the rotor, are first prepared. The functional axis of the supporting disk is aligned with the geometric axis of the functional axis fixture, and the geometric axis of the rotor is aligned with the geometric axis of the adjusting axis fixture. By engaging the functional axis fixture and the adjusting axis fixture, the functional axis of the supporting disk is aligned with the geometric axis of the rotor. Therefore, the bias and concentricity can be precisely controlled and improved.

1. Field of the Invention
The invention generally relates to a method and fixture for assembling supporting disk to a motor rotor, which is applicable to spindle motor for optical disk; and particularly relates to a method and fixture for assembling supporting disk to a motor rotor, through which the bias and concentricity are improved at one time.
2. Related Art
Accompanying with technical developments of mass data storage with optical disks, the precision requirements of spin motor for optical disk driver are getting higher and higher. In recent developments of HD-DVD, DVD-RAM and DVD-RW devices, for example, the axial bias and radial concentricity of the spin motor that carries optical disk have to be less than 0.015 mm and 0.03 mm respectively. An excellent performance and reliable data tracking of the disk driver relies on such a strict precision.
However, such precision requirements are very difficult for the current manufacturing process. FIGS. 1A and 1B illustrate a conventional spin motor and the method of measuring axial bias and radial concentricity. The spin motor 10 includes a stator 13, a rotor 12 and a supporting disk 111 mounted on the rotor 12. A plurality of jaws 111 are mounted in the central potion of the supporting disk 11 for grasping the center hole of an optical disk (not shown in the drawing) and driving the optical disk rotating along. In order to firmly grasp the optical disk, an anti-glide ring is usually formed concentrically around the jaws 111. The bias and concentricity of the spin motor 10 is checked as follows. Fixing the spin motor 10 on a base 14. Loading a measuring jig 15 on the supporting disk. The measuring jig 15 has a center hole 151 to be grasped by the jaws 111. Then, using micrometers 16a, 16b at top and circumference surfaces of the measuring jig 15 to measure the bias and eccentricity of the spin motor 10 by rotating the measuring jig 15.
The prior arts for improving the precision problems are usually by ways of improving component precision and adding supplementary processes during or after assembly. However, they still have difficulties and limitations as described below.
1) By Improving the Precision of Supporting Disk and Anti-glide Ring
Improving the precision of supporting disk is a straight and useful solution for improving the precision of spin motor. However, it is rather difficult to achieve the required bias and concentricity specifications by common process. Because the supporting disk has a complicated configuration that is usually made by plastic injection molding in order to lower the cost. The parameters of injection molding process, such as temperature, flow passage, thermal shrinkage and precision of mold, are complicated to control. Therefore, in order to meet the 0.03 mm concentricity requirement, the mold and the process have to be delicately modified and carefully controlled. The 0.015 mm bias requirement that depends on excellent molding and manufacturing techniques is further difficult to obtain.
Also, the 0.015 mm axial bias of the supporting plate requires thickness parallelity tolerance of the anti-glide ring being within 0.015 mm. It is not easy to achieve for rubber or silicone moldings that require specific molding and manufacturing attendance.
The aforesaid reasons make the component precision control difficult and expensive.
2) By Adding Supplementary Process During or After Assembly
It is possible to re-machine the assembly of rotor and supporting disk by lathing or grinding, or furnishing anti-glide material on surface of the supporting disk so as to improve the precision of the assembly. However, the post machining only improves the bias but does not help the concentricity. Further, the machining generates dusts that may cause trouble to the assembly. The furnishing of anti-glide material is less reliable because it cannot produce surface patterns that are preferred for a higher reliability.
Some manufacturers apply multiple anti-glide rings on the supporting disk. By using rings of different thickness, the bias can be reduced. However, the process is complicated and time-consuming. The process is also helpless to the concentricity.
In different applications of the supporting disks, there are also functional axis problems of columnar variance, vibration, angular shift, angular velocity, tangent velocity, acceleration and so on. However, these parameters, similar to aforesaid bias and concentricity, are caused by fixing and adjustment of the rotor and supporting disk and have bothered the manufactures for a long time.

Method for assembling supporting disk of motor rotor


A method to improve TCP throughput by separating TCP acknowledgment flow from TCP normal data flow in a wireless communications environment. This method creates dedicated signaling air interface link and signaling A10 link for TCP acknowledgment flow and assigns a higher priority value to TOS field of IP packets encapsulating TCP acknowledgments than those encapsulating TCP normal data.

1. Field of the Invention
The present application relates to improving TCP throughput in a wireless communications network, and more particularly to reducing TCP acknowledgment delays by separation of TCP acknowledgment transmissions in wireless networks.
2. Description of Related Art
Supporting TCP/IP based applications is mandatory in today's networking world. Users' demands for mobile services are increasing with greater diversity and complexity for the mobile communications market. Diverse and complex services are presenting unique challenges in supporting TCP/IP based applications in wireless environment.
IP applications over mobile systems are supported by existing standards that use IP to send data. However, to support enhanced IP applications such as FTP, HTTP and multimedia data services, mobile system applications rely on TCP (Transmission Control Protocol) to provide connection-oriented reliable byte-stream services.
The Transmission Control Protocol (TCP), documented in IETF RFC 793, makes up for IP's deficiencies by providing reliable, stream-oriented connections that hide most of IP's shortcomings. Transmission of a data packet is not regarded as complete until a corresponding acknowledgement packet ("ACK") is received. TCP adds a great deal of functionality to the IP service it is layered over.
FIG. 5(e) schematically shows how a segmented application message is encapsulated into a TCP segment, which is itself encapsulated in an IP packet.
FIG. 5(a) gives a large-scale view of a TCP/IP protocol architecture. IP applications over mobile systems are supported by existing standards that use IP 510 to send data. However, enhanced IP applications such as FTP 540, HTTP 530 and multimedia data services, which are desirable for use in mobile systems, rely on TCP 520 (Transmission Control Protocol) to provide connection-oriented reliable byte-stream services.
TCP algorithms operate in both directions, in an almost completely independent manner. A TCP session can be thought of as two independent byte streams, traveling in opposite directions. No TCP mechanism exists to associate data in the forward and reverse byte streams. Only during connection start and close sequences can TCP exhibit really asymmetric behavior (i.e. data transfer in the forward direction but not in the reverse, or vice versa).
Thus TCP is inherently duplex. (Duplex communications are the type of communications that transmissions can simultaneously happen at both directions.) However, if TCP data flow and TCP ACK flow are examined separately, TCP for some applications can be half duplex, or even simplex. Applications like FTP download are simplex: data is sent in only one direction (though control messages like request and ACK are sent in another direction at the same time). Applications like Database query are half duplex: data is sent in one direction in one time, then sent in another direction in other times. (Again, TCP control messages including TCP ACK can be sent in both directions simultaneously).
For duplex communications (where data is sent in both directions simultaneously), TCP employs a technique called piggybacking. Basically, TCP ACK info is carried on a TCP data segment. (ACK field in TCP header indicates whether the data segment contains ACK info or pure data). In that case the data and acknowledgement flows cannot be strictly separated.
Sequence Numbers
TCP uses a 32-bit sequence number that counts bytes in the data stream. Each segment (TPDU) contains the starting sequence number of the data in that segment, and the sequence number (called the acknowledgment number) of the last byte received from the remote peer. With this information, a sliding window protocol is implemented. Forward and reverse sequence numbers are completely independent, and each TCP peer must track both its own sequence numbering and the numbering being used by the remote peer.
TCP uses a number of control flags to manage the connection. Some of these flags pertain to a single packet, such as the URG flag indicating valid data in the Urgent Pointer field, but two flags (SYN and FIN) require reliable delivery as they mark the beginning and end of the data stream. In order to insure reliable delivery of these two flags, they are assigned spots in the sequence number space. Each flag occupies a single byte.
Window Size and Buffering
Each endpoint of a TCP connection will have a buffer for storing data that is transmitted over the network before the application is ready to read the data. This lets network transfers take place while applications are busy with other processing, improving overall performance.
FIG. 6 shows the relationship of TCP window size and delay. To avoid overflowing the buffer, TCP sets a Window Size field in each packet it transmits. In this example, it is set to w (reference number 610). This field contains the amount of data that may be transmitted into the buffer. If this number falls to zero, the remote TCP can send no more data. It must wait until it receives a packet announcing a non-zero window size.
Round-Trip Time Estimation
When a host transmits a TCP packet to its peer, it must wait a period of time for an acknowledgment 620. If the reply does not come within the expected period, the packet is assumed to have been lost and the data is retransmitted. The best value for the maximum wait depends on many factors. Over an Ethernet connection, no more than a few microseconds should be needed for a reply. If the traffic must flow over the wide-area Internet, a second or two might be reasonable during peak utilization times.
All modern TCP implementations seek to answer this question by monitoring the normal exchange of data packets and developing an estimate of how long is "too long". This process is called estimation of Round-Trip Time (RTT) 630. RTT estimates are one of the most important performance parameters in a TCP exchange. This is especially clear if we consider that, on a sufficiently large transfer, all TCP implementations eventually drop packets and retransmit them, no matter how good the quality of the link. If the RTT estimate is too low, packets are retransmitted unnecessarily; if too high, the connection can sit idle while the host waits to timeout.
Thus TCP throughput performance is greatly affected by the delay characteristics of the network which is carrying the IP packets. In a wireless environment the delay characteristics of the network can be more unpredictable, due e.g. to multipath characteristics, delays due to ARQ (automatic repeat request), and other factors discussed below.
The TCP sender bases its retransmission timeout (RTO) on measurements of the round trip delay experienced by previous packets. This allows TCP to adapt automatically to the very wide range of delays found on the Internet. If the path delay variance is high, TCP sets an RTO that is much larger than the mean of the measured delays. If the packet loss rate is low, the large RTO is of little consequence, as timeouts occur only rarely. Conversely, if the path delay variance is low, then TCP recovers quickly from lost packets; again, the algorithm works well. However, when delay variance and the packet loss rate are both high, these algorithms perform poorly, especially when the mean delay is also high.
Because TCP uses returning acknowledgments as a "clock" to time the transmission of additional data, excessively high delays (even if the delay variance is low) also affect TCP's ability to fully utilize a high-speed transmission pipe. It also slows the recovery of lost packets, even when delay variance is small.
Mobile systems should therefore minimize all three parameters (delay, delay variance, and packet loss) as much as possible. Often these parameters are inherently in conflict. For example, on a mobile radio channel, retransmission (ARQ) and/or forward error correction (PEC) can be used to trade off delay, delay variance, and packet loss in an effort to improve TCP performance. While ARQ increases delay variance, FEC does not. However, FEC (especially when combined with interleaving) often increases mean delay, even on good channels where ARQ retransmissions are not needed and ARQ would not increase either the delay or the delay variance.
The tradeoffs among these error control mechanisms and their interactions with TCP can be quite complex, and are the subject of much ongoing research. The common solution today is to adjust buffer sizes based on RTT estimate. For instance, when RTT increases, throughput is guaranteed by increasing the buffer size because Buffer_size=RTT* Bandwidth.
However, increasing buffer size will increase the cost of equipment. Further, it might worsen the delay since allowing more outstanding unacknowledged TCP segments will further congest the network or its communication peer.
Multi-Flow Packet Application
The Multi-Flow Packet Application provides multiple octet streams that can be used to carry octets between the access terminal and the access network.
CDMA2000 1x EV-DO
CDMA2000 1x EV-DO cell phone system is a standard that has evolved from the CDMA2000 mobile phone system and is now firmly established in many areas of the world. The letters EV-DO stand for Evolution Data Only or Data Optimized. It is a data only mobile telecommunications standard that can be run on CDMA2000 networks.
The forward channel forms a dedicated variable-rate, packet data channel with signaling and control time multiplexed into it. The channel is itself time-divided and allocated to each user on a demand and opportunity driven basis. A data only format was adopted to enable the standard to be optimized for data applications. If voice is required then a dual mode phone using separate 1X channel for the voice call is needed. In feet the "phones" used for data only applications are referred to as Access Terminals or ATs.
The forward link possesses many features that are specific to EV-DO, having been optimized for data transmission, particularly in the downlink direction. Average continuous rates of 600 kbps per sector are possible. This is a sixfold increase over CDMA2000 1X and is provided largely by the ability of 1xEV-DO to negotiate increased data rates for individual ATs because only one user is served at a time.
The forward link is always transmitted at full power and uses a data rate control scheme rather than the power control scheme used with 1X, and the data is time division multiplexed so that only one AT is served at a time.
In order to be able to receive data, each EV-DO AT measures signal-to-noise ratio (S/N) on the forward link pilot every slot, i.e. 1.667 ms. Based on the information this provides the AT sends a data rate request to the base station. The AN receives requests from a variety of ATs, and decisions have to be made regarding which ATs are to be served next. The AN endeavors to achieve the best data transfer, and this is done by serving those ATs offering a good signal-to-noise ratio. This is achieved at the expense of users at some distance from the AN's antenna.
Protocol Layering
Many telecommunications standards are defined in a layered structure. FIG. 4 shows an example of this (the HRPD air interface for the CDMA2000). The layered structure of the protocol will be helpful in understanding the operation of the implementations described below. Each layer consists of one or more protocols that perform the layer's functionality.                The Application Layer 410: provides multiple applications, including the Default Signaling Application for transporting air interface protocol messages. It also provides the Default Packet Application for transporting user data.        Stream Layer 420: The Stream Layer provides multiplexing of distinct application streams.        Session Layer 430: The Session Layer provides address management, protocol negotiation, protocol configuration and state maintenance services.        Connection Layer 440: The Connection Layer provides air link connection establishment and maintenance services.        Security Layer 450: The Security Layer provides authentication and encryption services.        MAC Layer 460: The Medium Access Control (MAC) Layer defines the procedures used to receive and to transmit over the Physical Layer.        Physical Layer 470: The Physical Layer provides the channel structure, frequency, power output, modulation, and encoding specifications for the Forward and Reverse Channels.Each layer may itself contain one or more protocols. Protocols use signaling messages or headers to convey information to their peer protocols at the other side of the air-link.

Systems and methods for wireless communications


A ground guide system for a trimming head of a powered vegetation trimmer, which may be of the type having a rotatable drum enclosing a spooled trimming cord and a bump feed mechanism on the bottom of the drum, comprises a housing above the drum, a hollow hub mounted within the housing and coupled to the drum for driven rotation therewith, an elongated mounting shaft slidably received within an axially extending sleeve fixed within the housing for upward and downward axially-directed motion, a spring for resiliently biasing the mounting shaft in a downward axial direction, and a ground guide threadably attached to the mounting shaft below the bump feed mechanism for adjusting trimming height. The mounting shaft includes an actuating ring arranged to operatively engage the bump feed mechanism incident to bumping the ground guide against a rigid environmental surface to restore a free end of the trimming cord.

A. Field of the Invention
The present invention relates generally to automatically powered vegetation trimmers, and more particularly to a novel ground guide system for the head of a powered trimmer which allows height adjustment and, in the case of cord- or filament-type trimmers, enables use of a bump feed mechanism common to such trimmers with or without the ground guide in place.
B. Description of the Prior Art
Automated trimmers of the prior art generally comprise a trimmer head at a distal end of a user handle, and are intended for free multi-directional movement of the trimmer head just above the ground to trim vegetation near obstacles such as trees, fences, and the like. Such automated trimmers commonly include a brush blade or a spool of filament cord mounted in the trimmer head for rotation at high r.p.m., whereby a free end of the cord extends tangentially outward from the spool to serve as a trimming means. The cord-type trimmers very often include a manual bump feed mechanism, for example as taught by U.S. Pat. No. 5,222,301, for advancing additional cord to restore the free end during use. The bump feed mechanism typically extends from the bottom of the trimming head and is actuated by momentarily bumping or impacting same against an environmental surface such as the ground.
A recognized drawback of automated trimmers of the type described above is that the height of the trimming means above the ground is constantly changing, resulting in an uneven cut. This is particularly true where the weight of the trimmer head overburdens the user's physical strength, as often happens with heavy-duty automated trimmers. A related problem is that of gouging, as may occur when the rotating trimming means is inadvertently allowed to contact the ground or other environmental surface.
In order to overcome the problems mentioned above, ground guide systems for powered trimmers have been proposed. U.S. Pat. No. 4,483,069, at FIG. 3 thereof, discloses a trimmer head including a "glide ball" having a smooth, downwardly facing convex surface. The glide ball is threadably mounted on the trimmer head beneath a rotating spool carrying trimming cord by an axially extending stud. The distance between the glide ball and the rotating spool is predetermined by the tightened threaded mating of the glide ball onto the stud, and there is no means provided to secure the glide ball at different threaded positions along the stud to adjust cutting height. Moreover, the structure shown is incompatible with conventional bump feed mechanisms.
U.S. Pat. No. 5,367,862 describes a ground guide attachment for a trimmer head in the form of a saucer-like disk having an upturned circumferential lip and a centrally located mounting post extending upward from the disk for attachment to an existing trimmer head. The mounting post, which is threaded at its remote end, is intended to be inserted through an axial bore in the cord spool and through a receiving hole in an upper support panel of the trimmer head housing, and secured with a nut apparently fixed to an upper support panel of the housing. This construction suffers the same drawbacks mentioned above with respect to U.S. Pat. No. 4,483,069, namely lack of height adjustability and lack of compatibility with conventional bump feed mechanisms.
A different style of ground guide system for automated trimmers is disclosed in U.S. Pat. No. 5,402,627. This patent teaches an elongated support ski having an upwardly extending slotted wall member at one end thereof. The wall member is adjustably fastened to an L-shaped upper member which in turn is fixed to an outer surface of a trimmer head housing. While the disclosed ground guide system is designed for cutting height adjustment, it prevents use of a conventional bump feed mechanism. In addition, the disclosed configuration is susceptible to clogging as cut vegetation accumulates on the wall member.
Another ground guide system offered for sale by Hoffco, Inc. of Richmond, Ind. under the trademark Ground Guard includes a wire surrounding the trimmer head in a generally vertical transverse plane to form side and bottom barriers around the trimmer head. A sliding handle must be operated by the user to raise and lower the wire guard to permit use of a bump feed mechanism. The configuration presents the opportunity for vegetation to accumulate on the wire and plug the trimmer head, and is not height-adjustable.

Height adjustable anti-gouging ground guide system for vegetation trimmer


A spectrographic type multiplexer and/or demultiplexer optical component having an array of waveguides, the component comprising a star inlet coupler and a star outlet coupler with said array extending therebetween, and also comprising an inlet light guide and an outlet light guide for said inlet and outlet couplers, respectively, wherein the spectrum response of the component is the sum of two substantially Gaussian spectrum responses of peaks that are offset in wavelength.

Spectrographic multiplexers having an array of waveguides conventionally comprise a dispersive array of light guides connected to inlet and outlet waveguides via two star couplers. The field in an inlet waveguide is reproduced in the plane of the outlet waveguides when the optical path length difference between two adjacent waveguides in the array is equal to an integer number of incoming wavelengths. Varying wavelength causes the distribution of the field over the outlet waveguides to be moved in translation. Such a configuration thus serves to separate different wavelengths in space.
By way of example, such components are used as a 1 to N demultiplexer, as an N to 1 multiplexer, or as an N to N multiplexer with switching.
A particularly advantageous application for such components lies in the field of optical fiber telecommunications, for example with high rate transmission (e.g. in a receiver circuit), or in optical distribution networks (wavelength separator), or in optical switching devices (highly integrated high speed electronic "chips" or between computers or within a computer).
As a general rule, the spectrum response obtained in an outlet waveguide from such a component corresponds to coupling a Gaussian beam into a Gaussian waveguide, and is thus itself Gaussian.
However, a Gaussian spectrum response requires accurate control over emitted wavelengths, thus making it difficult to use in a system. Unfortunately, the existence of small fluctuations in the wavelength at which a laser emits (fluctuations due to temperature) makes it necessary to be able to use channels having broader spectrum responses (or to servo-control the laser, which is difficult to do and expensive).
Broadening the spectrum response also makes polarization independence easier to achieve. The shape of waveguides is highly critical in obtaining polarization independence (whatever method is used). Thus, by having a flat spectrum response, the power received over a channel is independent of polarization, even if its TE and TM peaks are slightly offset (offset due to shape being slightly inaccurate).
Several techniques have already been proposed for making a spectrograph having an array of waveguides that presents a square type spectrum response.
In particular proposals have been made in: "Phased-array wavelength demultiplexer with a flattened wavelength response", University of Delft, M. R. Amersfoort, et al., IEEE Electronic Letters, February 1995, Vol. 30, No. 4; and "Polarization-independent InP-based phased-array wavelength demultiplexer with a flattened wavelength response", University of Delft, L. H. Spiekman et al., ECOC 94; to enlarge the outlet waveguides so as to obtain truly multimode outlet waveguides. Such multimode waveguides can couple with the incident beam over a broader range of wavelengths.
However, such multimode waveguides do not enable the outlet of such a spectrograph having an array of waveguides to be coupled to other elements such as another phasar, an optical amplifier, etc.
The very poor coupling between a multimode waveguide and a monomode fiber makes such a component unusable in monomode fiber networks.
Such spectrographs can be used only with photodiodes disposed at the outlet from the multimode waveguides in order to detect output powers.
Proposals have also been made in "Arrayed-waveguide grating multiplexer with a flat spectral response" NTT, K. Okamoto and H. Yamada, Optics Letters, January 1995, Vol. 20, No. 1, to achieve a "(sinx)/x" type power distribution in the array by modifying both the power distribution at the inlet to the waveguide array and the phase shifts of the waveguides in the array.
No practical embodiments have yet been achieved using that structure, for the following reasons: secondary power lobes are obtained in the array, making it necessary firstly to modify the mode shape in the inlet guide, which shape must be square, and secondly to provide additional phase shifting on the waveguides which correspond to the secondary lobes.
It will be understood that such a technique which involves modifying the inlet power shape and the phase shifting in the array of waveguides is difficult to implement, with poor control over manufacturing parameters giving rise very quickly to degraded component performance.
In particular, the phase shifting corresponding to the secondary lobes must be accurately controlled, since a positioning error on a waveguide concerning the additional phase shifting degrades the spectrum response very greatly and makes the phasar unusable.

Spectrographic multiplexer component having an array of waveguides