A reduced-frequency, 50% duty cycle corrector (DCC) circuit may be used in an electronic device (e.g., a memory chip) to generate output clocks with 50% duty cycle irrespective of the duty cycle of the clock input to the DCC circuit. A DCC initialization scheme selectively activates the frequency division and edge detection operations in the DCC based on the lock status of the DCC during initialization. Upon initialization, the frequency division and edge detection operations are turned off or disabled. After the DCC is properly locked, these operations are enabled to obtain the 50% duty cycle output clock. This approach initializes the reduced-frequency DCC without output glitches, which can affect locking of a DLL with which the DCC may be used. The prevention of instability in locking of the DCC and DLL upon system initialization results in swift establishment of DCC and DLL locks without significant power consumption or loss of clock cycles. Once the DCC is locked during its initialization, the reduced-frequency operation of DCC further saves current consumption. Because of the rules governing abstracts, this abstract should not be used to construe the claims.

1. Field of the Disclosure
The present disclosure generally relates to duty cycle corrector (DCC) circuits and, more particularly, to a DCC initialization scheme for a reduced-frequency, 50% DCC.
2. Brief Description of Related Art
Most digital logic implemented on integrated circuits is clocked synchronous sequential logic. In electronic devices such as synchronous dynamic random access memory circuits (SDRAMs), microprocessors, digital signal processors, etc., the processing, storage, and retrieval of information is coordinated or synchronized with a clock signal. The speed and stability of the clock signal determines to a large extent the data rate at which a circuit can function. Many high speed integrated circuit devices, such as SDRAMs, microprocessors, etc., rely upon clock signals to control the flow of commands, data, addresses, etc., into, through and out of the devices.
In SDRAMs or other semiconductor memory devices, it is desirable to have the data output from the memory synchronized with the system clock that also serves the microprocessor. Delay-locked loops (DLLs) are synchronous circuits used in SDRAMs to synchronize an external clock (e.g., the system clock serving a microprocessor) and an internal clock (e.g., the clock used internally within the SDRAM to perform data read/write operations on various memory cells) with each other. Typically, a DLL is a feedback circuit that operates to feed back a phase difference-related signal to control a delay line, until the timing of one clock signal (e.g., the system clock) is advanced or delayed until its rising edge is coincident (or "locked") with the rising edge of a second clock signal (e.g., the memory internal clock). The second clock signal may be supplied directly or through a duty cycle corrector (DCC) to various circuit components in the electronic device. In a memory device, for example, a 50% DCC circuit may be employed so as to more proportionately spread out data transfer windows, especially when data transfer takes place on both the rising and falling edges of the memory's clock. In case when the memory's clock (e.g., clock output from a DLL (not shown)) has 25% duty cycle, the data transfer window at the rising edge of the clock may be shorter than the window at the falling edge of the clock because of a disproportionate gap between the successive rising and falling edges of the clock. In the event that data transfers are performed with a 50% duty cycle clock, such imbalance may be avoided by having one data transfer window occurring at the rising edge of the 50% duty cycle clock and the second data transfer window occurring at the second rising edge in the same clock cycle of the 50% duty cycle clock.
FIG. 1 depicts a simplified block diagram of a prior art duty cycle corrector (DCC) circuit 10 that may be used in an electronic device (e.g., a memory device) to provide clocks of various phases (signals 19, 20, and 22 in FIG. 1) from an input clock signal 18. More specifically, the DCC circuit 10 may be used to obtain a clock that is exactly 180° out of phase with the input clock 18. A 50% duty cycle clock may then be obtained using such 180° out of phase clock (e.g., the output clock 22 in FIG. 1) as is known in the art. The DCC circuit 10 may be a phase generator configured to generate clocks of various phases. The phase generator 10 may include a pair of series-connected delay lines 12, 14, and a phase detector 16 forming a feedback loop. The input clock (Clock In) signal 18 may be received from a DLL (not shown in FIG. 1, but shown in FIG. 2 and discussed later hereinbelow) and supplied as an input to the first delay line 12 and also as an input to the phase detector 16. One of the outputs of the circuit 10 may be obtained directly from the Clock In signal 18 as a first output clock or Clock Out 0° signal 19. It is evident from FIG. 1 that there is no phase difference (0° of phase difference) between the input clock 18 and the first output clock 19. The second output of the phase generator 10 may be obtained from the output of the first delay line 12 as indicated by the Clock Out 180° signal 22 in FIG. 1. As the name for this second output suggests, the phase difference between the input clock 18 and the Clock Out 180° signal 22 is 180°. Whereas a third output of the phase generator 10 may be obtained at the output of the second delay line 14. This third output, the Clock Out 360° signal 20 in FIG. 1, has a 360° phase difference (i.e., delayed by one full clock cycle) from the input clock 18.
It is seen from FIG. 1 that the output 20 of the second delay line 14 is fed back as the second input to the phase detector 16, which, as is known in the art, compares the phase difference between its two inputs—the Clock In signal 18, and the Clock Out 360° signal 20—and generates a control signal 24 (which is supplied to both the delay lines 12, 14) to control the delays imparted by the delay lines 12, 14 so as to ensure that the loop delay (i.e., the delay between the input signal (Clock In 18) and the feedback signal (Clock Out 360° signal 20)) is exactly one clock cycle (1*tCK, where tCK is the input clock period). The two delay lines 12, 14 have the same control bits and, therefore, they impart same delay to their respective input clocks in response to the control signal 24. Because these two, matched delay lines divide the input clock 18 exactly into two portions, the "midpoint" clock (i.e., the output of the first delay line 12) is always 180° out of phase with the input clock 18 regardless of the input clock period or PVT (process, voltage, and temperature) variations. Thus, a 180° phase clock (the output signal 22 in FIG. 1) may be created using the topology of the phase generator 10. This topology may be expanded, as is known in the art, to arbitrary, multiphase clock generators (e.g., quadrature phase clock, etc.).
FIG. 2 shows a prior art circuit configuration 25 illustrating how a 50% DCC unit 26 is used in an electronic device. As noted hereinabove, a 50% duty cycle correction may be accomplished using the phase generator 10 along with appropriate logic circuits (not shown). However, a dedicated DCC that generates 50% duty cycle output(s) may be preferable in certain circuit configurations. The 50% DCC circuit 26 in FIG. 2 is one such dedicated DCC. As shown in FIG. 2, the 50% DCC 26 may be used in conjunction with a DLL 28. The DLL 28 provides synchronization between an external reference clock 30 and a device's internal clock (e.g., a clock that is used to perform various signal processing tasks within an electronic device or a memory chip). The external clock 30 may be typically the external system clock serving the microprocessor (and other system components present in the system along with the electronic device containing the DLL 28) or a delayed/buffered version of it. The system clock 30 may be supplied to the DLL 28 via one or more clock buffers (not shown). The other input to the DLL 28 may be supplied through the feedback loop that includes an I/O delay model 34, which receives the Clock Out 0° signal 19 at one of the outputs of the 50% DCC 26 and provides an appropriately delayed version of the output signal 19 (here, the feedback clock 36) to a phase detector (not shown) in the DLL 28 for phase comparison and clock synchronization. The I/O delay model 34 may function as a buffer or dummy delay circuit so that the output 36 ("the feedback clock") of the delay model 34 may effectively represent the internal clock that is provided to various circuit elements in the electronic device (e.g., a memory device) (not shown) containing the circuit configuration 25. Thus, the I/O delay model 34 attempts to maintain the phase relationship between the external clock 30 and the signal 36 as close as possible to the phase relationship that exists between the external clock 30 and the electronic device's (e.g., a memory's) internal clock, which, in FIG. 2, is one of the Clock Out 0° 19 or Clock Out 180° 22 signals.
It is noted here that for the sake of simplicity and ease of discussion, signals or circuit elements having similar functionality are referred to herein using identical reference numerals even though these signals or circuit elements may not be physically identical from one configuration to another. Thus, for example, the DLL Clock Out signal is given the same reference numeral "18′" as that given to the Clock In signal in FIG. 1 (and FIG. 3) because both of these signals function as inputs to a DCC (e.g., the phase generator 10 in FIG. 1, and the DCC 26 in FIGS. 2-3). Thus, a clock signal input to a DCC is referenced using the reference numeral "18" irrespective of the shape or duty cycle of the input clock. That is, the Clock In signal 18 in FIG. 1 and the DLL Clock Out signal 18 in FIG. 2 may not have identical shape or duty cycle, even though they have the same reference numeral. Similarly, for ease of discussion, all output clocks (e.g., Clock Out 0° signal 19, Clock Out 180° signal 22, etc.) from a DCC (whether a simple phase generator as in FIG. 1 or a dedicated 50% DCC as in FIGS. 2-3) are referred to herein using the same reference numerals despite the fact that these clocks may not be physically identical. Various common circuit elements (e.g., delay lines, phase detector, etc.) having similar functionality in different embodiments discussed herein are also referred to using identical reference numerals. As noted, the usage of same reference numerals for various DCC circuit elements and input/output clocks is preferred for ease of discussion only. It is further observed here that the additional mention of "50%" may be absent from the usage of the term "DCC" hereinbelow, but, it should be apparent from the context of discussion whether the term "DCC" refers to a "50% DCC" or any other form of DCC (e.g., the phase generator 10).
The DLL 28 may generate two output signals—the DLL Clock Out signal 18 and the DLL Lock Signal 32—both of which may be supplied as inputs to the 50% DCC 26. The DLL Clock Out signal 18 may be a phase synchronized version of the external clock 30, whereas the DLL Lock signal 32 may provide an indication to the DCC 26 when the DLL 28 is "locked" (e.g., when the rising edge of the system clock 30 is coincident with the rising edge of the feedback clock 36). The DLL Lock signal 32 may thus allow the DCC 26 to establish its own "lock" (discussed later hereinbelow). The DCC 26 corrects for any static duty-cycle problem in its input reference clock (i.e., the DLL output clock 18) and generates two output clocks—the Clock Out 0° signal 19, and the Clock Out 180° signal 22 having 0° and 180° phase differences, respectively, from the DCC input clock (i.e., the DLL Clock Out signal 18). Each of these two output clocks 19, 22, has a 50% duty cycle as the name "50% DCC" suggests.
FIG. 3 illustrates a detailed block diagram layout for the 50% DCC unit 26 of FIG. 2. As shown, the configuration of the DCC unit 26 is significantly similar to the phase generator 10 in FIG. 1, except for two changes that result in generation of output clocks with 50% duty cycles from an input clock of any other duty cycle. First, the Clock In signal 18 (input clock to DCC 26 from DLL 28 in FIG. 2) is not directly supplied to the first delay line 12 as in FIG. 1, but through a clock frequency divider unit 38. Thus, the input clock is supplied to the divide-by-2 frequency divider 38 that divides the input clock frequency by two. The output 40 (also designated by circled letter "A") of this frequency divider 38 is then supplied as an input to the phase detector 16, an input to the first delay line 12, and also as an input to a clock edge detector unit 42. Second, the output clocks 19, 22 are generated through the clock edge detector 42 instead of directly from the input clock 18 and the output from the first delay line 12 as was the case in FIG. 1. Thus, the output 44 (also designated by circled letter "C") of the first delay line 12 is supplied as a second input of the edge detector unit 42, which performs clock edge detection (here, a logic XOR or "exclusive OR" function) on the two input clocks 40, 44 to generate the 50% duty cycle output clocks 19, 22. The rest of the circuit elements and signals in FIG. 3 are identical to those shown in FIG. 1 and, hence, additional discussion thereof is not provided herein for the sake of brevity. It is, however, noted here that the Clock Out 360° signal 20 at the output of the second delay line 14 is conveniently referenced using a circled letter "B." Furthermore, only one of the DLL outputs from FIG. 2—the DLL Clock Out signal 18—is shown in FIG. 3 (as the Clock In signal 18), because of lack of relevance of the second output (i.e., the DLL Lock signal 32) with the present discussion. It is evident, however, that such DLL Lock signal 32 may be present as an input to the DCC unit 26 in a real life implementation.
Thus, in the configuration of FIG. 3, the incoming clock frequency is divided by two before the clock enters the delay loop of the DCC 26. Therefore, instead of attempting to lock rising edges of two phase detector input clocks as was the case in the configuration 10 of FIG. 1, the phase detector 16 in FIG. 3 is modified to lock the rising edge of the feedback clock 20 (circled letter "B") to the falling edge of its reference clock input (i.e., the clock signal 40 or circled letter "A" signal input to the phase detector 16) and vice versa. The intermediate output clocks 40, 44 are multiplied back up to the original frequency using edge detection through the edge detector unit 42 which performs XOR operation on its input clocks 40, 44 to obtain the final 50% duty cycle outputs 19, 22. In FIG. 3, both the rising and falling edges of the clock 40 are used (in phase detector 16, in delay line 12, and in XOR unit 42) to generate the final outputs 19, 22. Therefore, it is assumed that the delay lines 12, 14 preserve proper duty cycle of their respective input clocks so as to allow such dual-edge operation.
FIG. 4 illustrates the operation of the 50% DCC unit 26 in FIG. 3 through a set of waveforms of various clock signals in the 50% DCC unit 26. The signals in FIG. 4 are identified by corresponding reference numerals of various input, intermediate, and output clock signals in FIG. 3. It is shown in FIG. 4 that the phase detector 16 is modified to lock the rising edge of its first input clock 20 to the falling edge of its second input clock 40, and vice versa (i.e., locking the falling edge of clock 20 to the rising edge of clock 40) because of the input clock frequency division at block 38 (which aligns rising edge of one clock to the falling edge of the another of the two clocks 20, 40 as shown in FIG. 4). The Clock Out 360° signal 20 (represented by circled letter "B") is still 360° out of phase with the input clock 18, but with half the frequency of the input clock 18. The "midpoint" delayed signal—i.e., the intermediate clock 44 (circled letter "C")—at the output of the first 12 of the two matched delay lines 12, 14 is a delayed version (wherein the delay is determined by the control input 24 from the phase detector 16 as discussed hereinbefore) of the clock 40, but is not exactly 180° out of phase with the input clock 18 as can be seen from FIG. 4. However, the final output signal Clock Out 180° signal 22 is exactly 180° out of phase with the input clock 18, but with 50% duty cycle. Similarly, the other final output signal 19 is exactly in phase (0° phase difference) with the input clock 18, but with its duty cycle corrected to 50%.
It is seen from the waveforms in FIG. 4 that because of frequency division at block 38 (FIG. 3), all internal clock frequencies (of clocks 40, 20, and 44) have been reduced in half, therefore also reducing DCC current consumption by half (resulting in power savings). This frequency reduction, however, allows the DCC 26 to operate at still faster frequencies (of the input clock 18 and, hence, of the external system clock 30 (FIG. 2)) because of the same-speed limitations of the internal circuitry in an electronic device (i.e., all internal circuits within an electronic device should be capable of operating at the same clock speed). As noted before, the output signals 19, 22 are not only in the correct phase (in phase or 180° out of phase, whichever is applicable), but the duty cycle of each output clock 19, 22 is nearly equal to 50%, which is not the case for the output clocks 19, 22 in a non-frequency-divided version of DCC (i.e., the phase generator 10 in FIG. 1). In the non-divided version 10, the phases of output clocks 19, 22 are correct (in phase or 180° out of phase, whichever is applicable) with reference to the input clock 18, but the duty cycle of each output clock 19-20, 22 is the same as the duty cycle of the input clock 18. On the other hand, the duty cycles of the input 18 and output clocks 19, 22 may be different in the DCC circuit 26 in FIG. 3 as can be seen from the relevant waveforms in FIG. 4. The DCC unit 26 is a dedicated 50% DCC because it achieves the desired 50% duty cycle correction in its output clocks 19, 22 without any further processing.
The waveforms in FIG. 4 show the reduced-frequency 50% DCC 26 operating properly after the DCC feedback loop (formed by the clocks 40 and 20) is "locked" (i.e., the rising edge of the feedback clock 20 is locked or synchronized to the falling edge of the reference clock 40, or vice versa). However, at the time of initialization of the DCC 26, the output clocks 19 and 22 are very close in phase (which is determined by the minimum, intrinsic delay for each forward delay line 12 and 14). During this initialization, the XOR or edge detection function in the unit 42 will produce narrow glitches or pulses, or may not produce any output clock signal at all. FIG. 5 shows a set of waveforms of various clock signals in the 50% DCC unit 26 of FIG. 3 at the time of initialization of DCC 26 and before the DCC is "locked" (i.e., before the DCC feedback loop signals 20 and 40 are phase synchronized as noted hereinbefore). The narrow glitches or pulses in the output clocks 19, 22 are evident in their corresponding waveforms in FIG. 5. It is observed here that this problem of narrow glitches only affects the multiplied output (i.e., outputs 19, 22 from the XOR unit 42), but does not affect the fed-back clock signal (i.e., the Clock Out 360° signal 20). Therefore, the DCC 26 will eventually begin to lock (because the phase detector inputs 20, 40 are not affected by the multiplication operation in the XOR unit 42), and the pulses in the final outputs 19, 22 will start getting wider until they are at 50% duty cycle and the DCC loop is locked.
It is seen from FIG. 2 that the DCC 26 is placed after the DLL 28 in the signal propagation path (i.e., DCC 26 is in the forward-path delay of the system). In that situation, to ensure proper/careful initialization of DLL 28 and DCC 26, the following initialization sequence is used: (1) First, the DLL 28 is initialized and locked, and (2) once the DLL is locked and enters the quiescent state (as indicated by the assertion of the DLL Lock Signal 32 in FIG. 2), the DCC 26 is then allowed to lock (based on the status of the DLL Lock signal 32). In this sequential locking mechanism and because DCC 26 is in the forward-path delay of the system, if the clocks are lost because of the narrow pulse width upon DCC initialization (as shown by the narrow pulses in the waveforms for output clocks 19, 22 in FIG. 5), there may be no clock fed back to the DLL 28 because the glitches in the DCC output clock 19, which is fed back to DLL 28 as shown in FIG. 2, may collapse in the DLL feedback path (through the I/O delay model 34 shown in FIG. 2). In that case, the DLL 28 may lose its initial lock or cannot maintain it and, hence, may itself never initialize and may not allow DCC 26 to lock either. Such instability in establishing DLL and DCC locks may consume significant system time (in terms of many, wasted clock cycles of the system clock 30) and power before both of these components are locked, if at all.
It is therefore desirable to devise an initialization scheme for reduced frequency (obtained using input clock frequency division as discussed hereinbefore), 50% DCC that prevents the instability (noted above) in locking the DCC and DLL upon system initialization. It is also desirable that this initialization scheme for the 50% DCC be able to initialize swiftly, and properly lock the DCC (and DLL) without significant power consumption.

Initialization scheme for a reduced-frequency, fifty percent duty cycle corrector


A wireless access point software application, adapted to be run within a wireless access point, classifies network data packets with classification identifiers provided by RTC/RTE devices without scanning the content of them. The wireless access point software application receives inbound and outbound packet classification identifiers from the RTC/RTE applications running on the RTC/RTE devices. The identifiers are provided to a hardware data packet classifier. The hardware data packet classifier applies the identifiers against ingress packets and egress packets respectively. Data packets of the same class are assigned with a same priority. The prioritized network data packets are scheduled for transmission based on their respective priorities. The scheduled network data packets are forwarded to respective network interfaces for transmission.

Wi-Fi is a family of wireless networking technologies that are based on the IEEE 802.11 family of technical standards. Wi-Fi (also referred to herein as WiFi) technologies are commonly used for local area networking of electronic devices and Internet access. The electronic devices can be smartphones, tablet computers, laptop computers, desktop computers, and other types of devices. A Wi-Fi access point creates a local wireless network, and is operatively coupled to the Internet via, for example, a broadband modem. The broadband modem bridges the communication between the Wi-Fi access point and the Internet. Electronic devices access the Wi-Fi access point to access the Internet and communicate with each other. The Wi-Fi access point could also be a Wi-Fi hotspot. In such a case, the Wi-Fi hotspot can be created from, for example, a wireless access point, or a smartphone that accesses a public cellular network for accessing the Internet. The Wi-Fi hotspot can be provided by, for example, a public cellular network. As used herein, Wi-Fi access points and Wi-Fi hotspots are collectively referred to as Wi-Fi access points.
Electronic devices access the Wi-Fi network for many purposes. For instance, a mobile device (such as a smartphone, a tablet computer or a laptop computer) or a desktop computer runs a real-time communication application or real-time engagement application for text, audio, voice, video or both voice and video communication, such as instant messaging, voice over IP ("VoIP"), video teleconferencing, and online virtual meeting. Real-time communication ("RTC") and real-time engagement ("RTE") are the near simultaneous exchange of information over any type of telecommunications service with negligible latency. The immediacy of RTC/RTE is critically important for users. RTC/RTE software applications can be built in compliance with, for example, the Web Real-Time Communication ("WebRTC") framework.
An RTC/RTE software application running on a wirelessly networked device sends data (such as voice data, video data, text data, etc.) from the electronic device on which it is running to other electronic devices or servers. The data is sent from the electronic device to the Wi-Fi access point in the form of wireless signals, and referred to herein as upstream. The RTC/RTE software application also receives data (such as voice data, video data, text data, etc.) from other electronic devices or servers. The data is sent from the Wi-Fi access point to the electronic device in the form of wireless signals as well, and referred to herein as downstream. Downstream is received by the electronic device from the Wi-Fi access point while upstream is transmitted by the electronic device to the Wi-Fi access point.
The quality of the Wi-Fi access point's Wi-Fi signal can vary depending on the relative location, interference from other devices, the number of electronic devices on a particular wireless channel, conditions under which a mobile device accesses the Wi-Fi access point, and other factors. When the quality of the Wi-Fi signal is lower, the quality of users' experience ("QoE") of the RTC/RTE application becomes lower. QoE can be described and measured by a number of parameters, such as video resolution, choppy video time, video sharpness (also known as video clarity) and choppy audio time, latency, etc.
To maintain the immediacy of real-time communication or real-time engagement and a high level QoE, one conventional solution is to have a software application scan received network packets for the purpose of identifying the categories of them, and assign different priorities to the packets. Time critical packets, such as those for real-time communication or real-time engagement, are assigned with a higher priority. Packets with higher priorities are forwarded to the target network interface for transmission before packets with lower priorities. However, the classification process is time consuming. Accordingly, it is desirable for an improved Wi-Fi access point and method to perform the classification with classifier identifiers provided by the RTC/RTE devices to avoid the scanning of the packets and thus achieve better performance. Furthermore, it is desirable for the improved Wi-Fi access point to classify the network packets at the hardware layer to achieve better performance by providing the classification identifiers to the hardware classifier.

This patent is subject to a terminal disclaimer.

Wireless access point software application for classifying network data packets to improve packet forwarding performance


A handheld apparatus for adjusting orthodontic wire includes first and second handle portions and a jaw portion. The first handle portion pivotably couples to the second handle portion such that the first and second handle portions are capable of pivoting with respect to each other at a pivot axis. The jaw portion extends from the first and second handle portions. The jaw portion includes: a first prong extending from the first handle portion; and second and third prongs extending from the second handle portion. The second and third prongs each include: a respective inner surface that partially defines a slot between the second and third prongs; and first and second outer surfaces joined together by a transition region.

Arch wires are frequently used in orthodontic techniques to transmit correctional forces used to align the teeth. The forces applied by arch wires may be capable of moving a tooth in a particular direction over time. A resulting stress is created within the periodontal ligament. The modification of the periodontal blood supply determines a biological response which leads to bone remodeling, where bone is created on one side by osteoblast cells and resorbed on the other side by osteoclast cells. Arch wires may be adjusted at various locations to create particular moments of force.

Apparatus and method for adjusting orthodontic wire


A process for preparing a high purity (meth)acryloyloxyalkyl isocyanate having a very small hydrolyzable chlorine content is provided. The high purity (meth)acryloyloxyalkyl isocyanate is prepared by subjecting a hydrolyzable chlorine containing (meth)acryloyloxyalkyl isocyanate to mixing treatment with an epoxy compound and an amine at a temperature of from 110 to 160° C. to prepare a mixture; and preparing a high purity (meth)acryloyloxyalkyl isocyanate from the resulting mixture with distillation. In particular, it is possible to effectively prevent (meth)acryloyloxyalkyl isocyanate from polymerization during the distillation by adding a polymerization inhibitor such as phenothiazine and the like.

(Meth)acryloyloxyalkyl isocyanates typified by methacryloyloxyethyl isocyanate are industrially very useful compounds containing, per molecule, an isocyanate group having high reactivity with a compound having an active hydrogen, such as compounds having a substituent e.g. a hydroxyl group, or primary or secondary amino group, and a carbon-carbon double bond capable of vinyl polymerization. They are used in various purposes, for example, paints and coating materials, adhesives, photo-resists, dental materials and magnetic recording materials.
As described in U.S. Pat. No. 2,821,544 and JP-A-S54(1979)-5921, these compounds are prepared by using phosgene and generally contain impurities called as hydrolyzable chlorine.
When urethane acrylate and the like are prepared using a (meth)acryloyloxyalkyl isocyanate containing hydrolyzable chlorine, the hydrolyzable chlorine works as a catalyst poison and also a chlorine compound contaminated in a product affects the weathering resistance and corrosion resistance of the resulting product. Particularly, when the (meth)acryloyloxyalkyl isocyanate containing hydrolyzable chlorine is used to photo-resist materials for electronic apparatus parts, the presence of hydrolyzable chlorine may induce a serious problem.
Conventionally, various methods of decreasing the amount of hydrolyzable chlorine in an isocyanate compound are proposed.
There are known methods, for example, a method of mixing a hydrolyzable chlorine containing isocyanate compound with a minute alkali metal carbonate at a high temperature for a long period of time, a method of adding a zinc carboxylate and a hindered phenol oxidizing agent to a hydrolyzable chlorine containing isocyanate compound, subjecting to heat treatment, followed by distillation, a method of synthesizing an isocyanate in a solvent insoluble in water, and washing with a sodium hydrogen carbonate aqueous solution, and a method of treating a hydrolyzable chlorine containing polymethylene polyphenyl isocyanate with an epoxy compound. Furthermore, as a method without using a drug such as alkali metal carbonate and the like, there is a method of vaporizing a hydrolyzable chlorine containing isocyanate compound and condensing at a temperature of not lower than 70° C.
These methods, however, cannot decrease the amount of hydrolyzable chlorine sufficiently, or have various problems for solving in order to carry out them industrially. For example, in the method of mixing a hydrolyzable chlorine containing isocyanate compound with a minute alkali metal carbonate at a high temperature, it is difficult to separate the isocyanate compound and the carbonate after the treatment so that the occurrence of loss cannot be avoided. In the method of washing with a sodium hydrogen carbonate aqueous solution, white insoluble matters are deposited on the boundaries between an organic phase and a water phase and the matters cause obstacles in the subsequent separation procedure, or apparatus pollution. In the method of using the sodium salt, the isocyanate compound is liable to be contaminated by sodium ion, and even if the sodium ion content is in the level of ppm, it causes a serious problem in the case of using the isocyanate compound to electronic materials.
In particular, when an isocyanate compound having a carbon-carbon double bond is purified, it is desired to prevent the isocyanate compounds from polymerization reaction and simultaneously to decrease the content of hydrolyzable chlorine effectively. However, the above method cannot lead to the satisfactory results.
U.S. Pat. No. 4,310,688 discloses that a methylene chloride solution of methacryloyloxyethyl isocyanate containing 0.21% of hydrolyzable chlorine is treated with a compound containing a vicinal epoxy group (example: 1,2-butylene oxide) to decrease the hydrolyzable chlorine content to 0.05% by mass. However, this method can decrease the hydrolyzable chlorine content to several hundred ppm at the most, and the purified isocyanate compound prepared by this method is insufficient for the use including electronic materials and the like.
In order to solve the above problems associated with the prior arts, a method of treating with an epoxy compound in the presence of an amine is disclosed as a method of decreasing the hydrolyzable chlorine content in the isocyanate compound (JP-A-H9(1997)-323968. This method is an excellent method, but it cannot remove hydrolyzable chlorine completely. Therefore, the advent of a method of further decreasing the hydrolyzable chlorine content has been desired.
JP-A-H11(1999)-228523 discloses a method of preparing a (meth)acryloyloxyalkyl isocyanate substantially free from hydrolyzable chlorine by adding an amine and an epoxy group containing compound, heating and then purifying with distillation to prepare a purified acryoyloxyalkyl isocyanate substantially free from 2-chloro propionic acid isocyanate alkyl ester, or to prepare a purified methacryloyloxyalkyl isocyanate substantially free from 2-methyl-2-chloropropionic acid isocyanate alkyl ester. This method, however, has many problems in industrialization thereof such that in the case of carrying out distillation once after the addition of an amine and an epoxy group-containing compound, one having a hydrolyzable chlorine content of only 29 ppm is prepared and further, in order to further decrease the hydrolyzable chlorine content, it is necessary to conduct precision distillation.
Meanwhile, a method of preparing an isocyanate compound without using phosgene has been studied. With regard to (meth)acryloyloxyalkyl isocyanates, a method of pyrolysis of an urethane compound is proposed. The process comprises the step of pyrolysis at a high temperature, but the yield is not satisfactory economically because the (meth)acryloyloxyalkyl isocyanate is very easily polymerizable. Furthermore, a method of preparing an isocyanate compound at a relatively lower temperature by making an urethane compound into a dealkoxy silane with silanization is proposed, but in this method, an expensive compound is necessary and unnecessary wastes are produced. Further, this method has no description on the yield, so that it has many economic problems in industrialization.

Process for preparing high purity (meth) acryloyloxyalkyl isocyanate


The invention relates to a device for cleaning a horizontal drain (10) adapted for being disposed at the end of two concentric pipe columns (14, 16). This device includes a body (20) provided with at least one cleaning fluid outlet port (38) and with at least one return port (30) for the fluid loaded with particles.. The outlet ports are directed towards the wall of the drain and located at a predetermined distance from the return ports.. The invention further relates to an installation for the cleaning of horizontal drains and to a method for implementing the installation.

It is known that the placing of wells in production in sandy deposits, with the aid of horizontal or slightly sloping drains, results in the sand being carried by the fluid flowing from the deposit and results in large deposits of sand or other sediments, mainly in the horizontal part of the drains. This causes a considerable decrease in the production of the well and sometimes makes it impossible to introduce measuring or intervention tools down into the drain.
U.S. Pat. No. 4,744,420 describes a known device for cleaning such horizontal drains which includes, at the end of two concentric pipe columns, a body fitted with nozzles for projecting a cleaning fluid, this body delimiting a cleaning fluid feeding passage connected to said nozzles, as well as a passage for the return of this fluid loaded with solid particles of sand or other sediments, these two passages being respectively connected to one of the two pipes delimited by the two concentric pipe columns.
In this known device, the nozzles for projecting cleaning fluid are disposed at the end of the body and are orientated substantially parallel to the axis of the drain. Such a lay-out tends to expel in front of the device the sand and other sediments accumulated in the drain.
It is this particular problem which the invention proposes to resolve so as to carry out a more effective cleaning of such horizontal drains.
European Patent No. 417,009 mentions a known device including deflecting means adapted for directing the cleaning fluid jet coming out of a nozzle in the direction of the wall of the drain.
The deflector may however be a mechanically fragile part with certain dimensions of the device. Besides, the equipment does not allow the distance between the turbulence zone of the cleaning fluid at the outlet of the nozzle and the suction zone to be adjusted.
It has been established that adjusting this distance is important because it conditions the proper return circulation towards the sucking device of the fluid loaded with sediments. In fact, the purpose of the fluid spurting out of the outlet ports is to stir and to carry along the sediments towards the sucking device. To this effect, the outlet ports are disposed, with respect to the suction ports, in such a way that the stirring turbulences are sufficiently distant from the suction ports in order not to impede the direction of circulation of the fluid intended to carry along the sediments, and at the same time close enough for the suction effect to act effectively on the fluid loaded with sediments suspended by said turbulences.
The parameters acting upon this distance may be notably the available rate of circulation of the fluid, the mean viscosity of the fluid loaded with sediments, the diameter of the drain, the density of the sediments or the rheology of the cleaning fluid.

Device and installation for the cleaning of drains, particularly in a petroleum production well


A trim adjusting device for a surface boat is provided that includes a nozzle for projecting jet water rearward arranged rearwardly of a jet propeller arranged in a boat body; a nozzle drive mechanism connected to the nozzle for operating the nozzle upward or downward; and an operating means arranged on a handle being connected to the nozzle drive mechanism. The nozzle drive mechanism includes a lever member connected to a trim operation lever of the operating means, a cam member provided with an engaging portion that engages the lever member arranged so as to be capable of rotating freely, a reverse rotation preventing claw member that engages the engaging portion, a link member that comes into abutment with the cam member at one end thereof, and the nozzle connected to the other end of the link member.

Trim adjusting devices for small surface boats have been known, in which the direction of a nozzle is changed by an electric power by operating an operating unit arranged on a handle.
For example, Japanese Patent No. 3397856 discloses a technique in which the direction of a nozzle is changed by operating an operating unit provided on a handle and pulling a cable connected to the operating unit. In this reference, a trim adjusting device for a jet-propelled boat is configured in such a manner that by squeezing and rotating an outer pipe 22 arranged on an operating handle 2 by hand and pulling one of operating cables 60, 60, a rotary plate 32 of a converter 3 rotates, pulls and pushes an operating cable 30, whereby a water injection port 5 can be directed obliquely upward or obliquely downward.
However, one problem associated with this type of trim adjusting device is that when the operator grips and rotates the outer pipe 22 disposed on the operating handle 2 by hand, the operator's hand may slip unless the operator grips with a strong grip, and hence the operator has to grip with a strong force. In particular, when it is operated during travel, the operator has to operate the water injection port 5 to be directed obliquely upward or obliquely downward against a pressure of jet water being injected. Therefore, the operator has to rotate the outer pipe 22 with a strong force and with a strong grip, which is difficult to operate.
According to the trim adjusting device disclosed Japanese Patent No. 3397856, the water injection port 5 is directed obliquely upward or obliquely downward by an angle corresponding to notches 71, 73 formed on a housing 7 of the operating handle 2. However, the water injection port 5 cannot be directed to other angles, for example, further downward than in the related art.

Trim adjusting device for small surface boat


A platform system for self-leveling a stage is provided and includes one or more module assemblies and one or more supports. Each module assembly includes one or more receiving members for engaging and removably securing the one or more supports. Each support includes an elongate portion, an extendible portion extendible from and lockingly engageable with the elongate portion, a base member removably attached to the extendible portion, and an actuator assembly secured to the elongate portion and in communication with the extendible portion. The actuator assembly is configured to rapidly extend and lockingly engage the extendible portion and the base member to provide self-leveling of each of the one or more module assemblies of the stage as the base member engages an underlying surface.

Stages and platforms can require use of tools, such as wrenches or screwdrivers, and/or hammers for assembly and/or disassembly. Locking mechanisms for supports have been used; however, they are difficult to assemble and disassemble, subject to misalignment, require a plurality of pieces, require tools for certain adjustments, do not offer adequate stability, do not have easily replaceable parts, and do not work well in conjunction with other parts of the stage or platform structures. Further, known stages and platforms require the design and insertion of various shims under the support legs to account for uneven surfaces, and do not self-level quickly during assembly.
What is needed is a self-leveling platform system, self-leveling support, and a method of assembling a self-leveling platform system that do not suffer from one or more of the above drawbacks in the art.

Self-leveling platform system, self-leveling supports, and method of assembling a self-leveling platform system


An organic light emitting diode (“OLED) display comprises a plurality of pixels which receives a first data signal, which is a data signal of a frame, through a plurality of data lines connected thereto, and stores the first data signal during a frame period of the frame, where the pixels simultaneously emit light based on a driving current corresponding to a second data signal, which is a data signal of a previous frame, where the frame period includes a scan period, during which the first data signal is stored, and a light emission period, during which the light is emitted based on the second data signal, the scan period and the light emission period overlap each other in the frame period.

1. Field
Exemplary embodiments of the invention relate generally to an organic light emitting diode ("OLED") display and a driving method thereof.
2. Description of the Related Art
A display device has been used for a personal computer, a portable phone, a portable information terminal such as a personal digital assistants ("PDA"), and the like, or monitors of various information devices. The display device typically includes a liquid crystal display ("LCD") using a liquid crystal panel, an organic light emitting diode display ("OLED") using an organic light emitting element, a plasma display panel ("PDP") using a plasma panel. Particularly, the OLED display has high luminance efficiency and wide viewing angle and quick response speed.
The OLED display typically includes a display area formed by arranging a plurality of pixels substantially in a matrix form on a substrate, and a data signal is selectively applied to a pixel by connecting a scan line and a data line to each pixel for displaying an image.
Such an OLED display is typically classified into a passive matrix type OLED display and an active matrix type OLED display. The passive matrix OLED display typically includes a positive electrode and a negative electrode disposed to cross each other and is driven on a line-by-line basis.
The active matrix type OLED display is driven by controlling a current flowing to an organic light emitting diode by maintaining data signal switched by a switching transistor with a capacitor and applying the data signal to a driving transistor. Such an OLED display may be used in a stereoscopic display device that displays a stereoscopic image.
FIG. 1 is a conceptual diagram showing a conventional driving method of an active matrix type of OLED display.
Referring to FIG. 1, a frame period for displaying a stereoscopic image is divided into sub-frames of a left-eye image section LI and a right-eye image section RI. The left-eye image section LI includes a scan section LN1 for writing left-eye image data and a light emission section LE1 for light emission based on the left-eye image data, and the right-eye image section RI includes a scan section RN1 for writing right-eye image data and a light emission section RE1 for light emission based on the right-eye image data.
As described above, a left-eye image and a right-eye image are sequentially displayed during a frame period corresponding to a driving frequency (e.g., 60 Hz), and shutter glass ("SG") type spectacles are selectively opened and closed to realize a stereoscopic image at a time when the left-eye image is displayed and at a time when the right-eye image is displayed.

Organic emitting display device and driving method thereof


The present invention provides new drum lift indicators and inventory control devices for use with drum handling equipment. The drum lift indicators and inventory control devices provide signals indicative of whether drums are properly clamped in the drum lifting equipment. The devices may also provide various other information, for example a count of the number of drums lifted and the amount of time the drum lift indicator and inventory control device is in service. One drum lift indicator and inventory control device according to the present invention has a clamp sensor positioned on a drum lifting clamp, in which the clamp sensor has a sensor signal indicative of whether the drum lifting clamp is clamped onto the drum. A drum clamp indicator is connected to the drum clamp sensor and receives the sensor signal from the clamp sensor. An operator receivable indicator signal is produced by the clamp indicator in response to the sensor signal when the drum lift clamp is clamped onto the drum.

Drums are widely used containers for holding, storing and transporting various types of materials. Materials contained within drums may include, for example, liquids, chemicals, solids, pellets and a wide variety of other types of materials. Due to the size and weight of drums and the need to safely and efficiently manipulate drums various types of drum handling equipment have been designed. Existing drum handling equipment includes forklift attachments, handmovable lifting trucks, and overhead crane and hoist operated attachments. Drum handling equipment has also been designed to handle single drums or multiple drums, for example, forklift, crane and hoist operated attachments are particularly useful for handling multiple drums.
Drum lifting equipment typically includes a drum lift clamp or mechanism which holds the drum for lifting and transporting of the drum. Existing drum lifting equipment has not included an indicator that the drum is clamped by the drum lifting equipment. Such an indication that the drum is clamped by the drum lifting equipment would be useful for an operator of the device. For example, an operator of a forklift attachment for lifting drums would be informed that the forklift attachment is clamped onto the drum and the forks can then be lifted and the drum transported. Generally, operators who operate drum lifting equipment, such as forklift operators, are unable to see whether the drum lift clamp is properly clamped onto a drum. Accordingly, an advantage would be to provide drum lift equipment operators with a signal indicating whether the drums are properly clamped and ready for lifting and transporting. Providing the drum lift equipment operator with signals indicating whether drums are properly clamped in the drum lift equipment would also improve the safety of lifting and transporting drums.
Existing drum handling equipment has also not provided inventory control and management features. Cost effective management and control of inventory is an objective of many businesses. A variety of information regarding handling of drums may be desirable, for example, counting the number of drums lifted, measuring the weight of drums lifted, and tracking elapsed time of operation of the drum lifting equipment. In addition to inventory management and control of drums and drum contents, information about handling drums may be useful for other purposes, such as maintenance purposes. Drum lifting equipment may be periodically serviced, and tracking the time the drum lifting equipment is in service can assist in proper maintenance of the equipment.
Previously, such information was manually accumulated or in some cases not even acquired at all. For example, the number of drums lifted and transported has been manually counted and drums have been weighed by taking the extra steps of placing the drums on a scale. Accordingly, it would advantageous to automatically track various information pertaining to drum lifting and transporting.
Therefore, there would be advantages to having new drum lifting equipment, particularly drum lifting indicators and inventor control devices. One specific advantage would be to have a drum lift indicator which indicates to the equipment operator that the drum is properly clamped in the lifting equipment. Another advantage would be to have a drum lift inventory control device which counts the number of drums lifted. Another advantage would be to have drum lift equipment which measures the weight of the drums when the drums are lifted. Yet another advantage would be to have drum lift equipment which assists in maintaining the equipment by providing information on use of the equipment. Other advantages of having new drum lift equipment will become apparent in view of the present invention.

Drum lift indicators and inventory control devices


The present invention is a thermal processing unit that includes: a tubular processing container; an object-to-be-processed holding unit that holds a plurality of objects to be processed in a tier-like manner and that can be inserted into and taken out from the processing container; a process-gas introducing unit that introduces a predetermined process gas into the processing container; a heating unit provided in the processing container, the heating unit heating the plurality of objects to be processed held by the object-to-be-processed holding unit when the object-to-be-processed holding unit is inserted into the processing container; and a container cooling unit that cools an outside wall surface of the processing container.

In general, in order to manufacture a desired semiconductor integrated circuit, various thermal processes including a film-forming process, an etching process, an oxidation process, a diffusion process, a modifying process or the like are carried out to a semiconductor wafer, which consists of a silicon substrate or the like. These thermal processes may be conducted by a longitudinal batch-type of thermal processing unit. In the case, at first, from a cassette that can contain a plurality of, for example 25 semiconductor wafers, semiconductor wafers are conveyed onto a longitudinal wafer boat. For example, 30 to 150 wafers (depending on the wafer size) are placed on the wafer boat in a tier-like manner. The wafer boat is conveyed (loaded) into a processing container that can be exhausted, through a lower portion thereof. After that, the inside of the processing container is maintained at an airtight state. Then, various process conditions including a flow rate of a process gas, a process pressure, a process temperature or the like are controlled to conduct a predetermined thermal process.
Herein, with reference to FIG. 10, an example of a conventional thermal processing unit is explained. The thermal processing unit 2 has a longitudinal processing container 8 with a predetermined length, which has a double-tube structure of an inner tube 4 and an outer tube 6 and is made of quartz. In a processing space S in the inner tube 4, a wafer boat 10 made of quartz is contained as a holder for holding the object to be processed. Semiconductor wafers W as objects to be processed are held on the wafer boat 10 in a tier-like manner at a predetermined interval (pitch).
A cap 12 is provided for opening and closing a lower portion of the processing container 8. A rotation shaft 16, which can rotate via a magnetic-fluid seal 14, is provided at the cap 12. A rotation table 18 is provided on an upper end of the rotation shaft 16. A heat-insulating cylinder 20 is provided on the table 18. The wafer boat 10 is placed on the heat-insulating cylinder 20. The cap 12 is attached to an arm 24 of a boat elevator 22 that can be moved up and down, so that the cap 12 can be moved up and down together with the rotation shaft 16 and the wafer boat 10 and the like. Because of the up-and-down movement by the boat elevator 22, the wafer boat 10 can be inserted into or taken out from the processing container 8 through a bottom portion of the processing container 8.
A manifold 26 made of for example stainless steel is joined to a lower-end opening of the processing container 8. A plurality of (two in the shown example) gas nozzles 28A, 28B penetrates the manifold 26 for introducing various process gases necessary for a thermal process, for example a film-forming process, into the processing container 8. The respective gas nozzles 28A, 28B are connected to respective gas supplying systems 30A, 30B. In the respective gas supplying systems 30A, 30B, flow-rate controllers 32A, 32B such as mass-flow controllers that can control gas flow rates are respectively provided.
Then, the respective process gases supplied from the respective gas nozzles 28A, 28B ascend in the processing space S (wafer containing region) in the inner tube 4, turn down at a ceiling portion and descend in a gap between the inner tube 4 and the outer tube 6.
A gas-discharging port 34 communicating with the gap between the inner tube 4 and the outer tube 6 is provided at a side wall of the manifold 26. A vacuum pump not shown and the like are connected to the gas-discharging port 34. Thus, a vacuum can be created in the processing container 8.
A heat-insulating barrier 36 consisting of a heat-insulating material is provided outside the processing container 8. A heater 38 as a heating means is provided inside the heat-insulating barrier 36. Thus, the wafers W in the processing container 8 are adapted to be heated to a predetermined temperature.
The conventional thermal processing unit 2 is designed to conduct a thermal process, such as a film-forming process or an oxidation-diffusion process, at a relatively high temperature zone of for example 900 to 1200° C. In view of thermal stability at the relatively high temperature zone and so on, the heat-insulating barrier 36 is designed to be relatively thick so as to have large thermal capacity. In addition, in order to rapidly lower the temperature of the processed wafers, a thermal processing unit has been proposed wherein a cool wind is blown to an outside surface of the processing container (for example, JP laid-Open Publication No. 2000-100812).
Recently, it is possible that the semiconductor wafers have to be thermally processed at a relatively low temperature zone of for example 50 to 600° C., instead of the relatively high temperature zone of for example 900 to 1200° C. For example, in order to grant a request of high-speed operation of a semiconductor device, if copper wiring that has been recently paid attention to is formed to reduce wiring resistance, it may be necessary to conduct an annealing process to copper films coated on the wafers at a relatively low temperature of about 50 to 150° C. In addition, in order to reduce wiring capacity, if an organic film whose dielectric constant is small, such as a resin, is used as an interlayer dielectric film, it may be necessary to vitrify the organic film at a relatively low temperature of about 400 to 600° C.
When a thermal process is conducted at the above low temperature zone, if the thermal processing unit 2 as shown in FIG. 6, which is designed for the high temperature zone of for example 900 to 1200° C. and which has the large thermal capacity, is used, it may take a very long time to lower the wafer temperature to a handling temperature that is around a room temperature, even if the thermal process is conducted at the low temperature. For example, as described above, since the heat-insulating barrier 36 is thick and has the large thermal capacity, a rate of temperature fall in the high-temperature zone of about 900 to 1200° C. is 5 to 6° C./min, which is large, but a rate of temperature fall in the low temperature zone of around 100° C. is 1 to 2° C./min, which is very small. The phenomenon in the low temperature zone may be also found in another unit wherein a cooling wind is blown to a side wall of a processing container 8.
If it takes a long time to lower the temperature of the processed wafers to the handling temperature, throughput is remarkably deteriorated.


An apparatus for attachment to a commercially available cleaning wand for maneuvering the wand inside a storage tank. Two arms each have an end pivotally connected to a handle and another end pivotally connected to the wand to form a four bar linkage. A gimbal arrangement is supported above a base, which is placed over an opening in the tank, and one of the arms is coupled to the gimbal arrangement to allow movement about three mutually perpendicular axes for directing the wand to various orientations within the tank.

Various storage tanks, including rail car tanks and other vessels require periodic inspection and internal cleaning to remove fluid or debris built up on the interior tank wall. For example, the tank is cleaned through a manway, or opening, with a lancing, or cleaning wand which is supplied with high-pressure fluid. To clean or inspect the interior an operator generally holds the inspection equipment or cleaning wand through the opening while laying on a personnel platform. If such a platform is not part of the tank structure, a portable staging platform is erected for this purpose.
This method of cleaning the tank is cumbersome and uncomfortable for the operator. Further, it is difficult for the operator to hold and direct the cleaning wand while in the prone position. The present invention eases the cleaning operation, allowing it to be done with less effort and in a shorter period of time. Further, for inspection purposes, the present invention allows for easy, controlled inspection of the tank interior.

Apparatus for maneuvering a device within the interior of storage tanks

The United States of America as represented by the Secretary of the Navy


A blender apparatus specifically adaptable for intermixing solid and liquid materials is made up of a housing for an impeller assembly having upper and lower impeller portions and wherein liquid directed into the lower impeller portion is redirected axially into the upper impeller portion for intermixing with solid materials directed into the upper impeller portion and undergo outward radial movement through the upper impeller portion into an outer peripheral area surrounding the impeller portions for subsequent discharge therefrom.

The invention relates to a method and apparatus for mixing together liquid and solid constituents, and more particularly to a novel and improved method and apparatus for high-capacity blending of solid particles and liquids, and specifically relates to a centrifugal pump blender for optimizing continuous, high-volume mixing of a granular or particulate solid with a liquid.
The invention is directed to certain improvements in a mechanical blender, and is particularly useful in oil and gas well field activities where thorough intermixing and rapid discharge of high volumes of solid and liquid components often is necessary, such as, in subsurface fracturing and down-hole cementing operations. Large volume blenders are generally of two basic types, "batch" mixers and "continuous" mixers. Batch mixers, in which large volumes of admixtures are agitated together, have generally passed from the scene owing to their need for a large mixing reservoir, which severely impacts portability, and also because they do not readily permit rapid changes in the characteristics of the mixture produced.
Presently more common are continuous mixing devices. One type of continuous mixer known in the art has two impellers coupled upon a single vertical drive shaft and within a generally cylindrical casing or housing. The upper impeller, commonly called a "slinger" or "thrower," receives granular, particulate or pulverous solids material at its center by a simple gravity feed straight down through a centrally located hole in the upper casing. The upper thrower, when spinning upon the shaft, projects the solid material toward a peripheral zone beyond the circumference of the impeller. Liquid is pumped or otherwise introduced through an opening in the lower housing and is pushed by centrifugal force generated by the lower rotor or impeller to the peripheral zone. Mixing of the solids and liquid occurs primarily in the peripheral zone between the two impellers and beyond their peripheries after which the mixture is forced through a discharge outlet in the housing.
An aspect common to most prior art devices is the creation of a gradient of increasing pressure from the central axis of rotor rotation outwardly toward the peripheral zone, the peripheral zone manifesting the highest pressures within the housing. Consequently, once liquid or solid materials are forced into the peripheral zone, intimate mixing occurs rapidly therein; however, the same high pressures which promote thorough mixing of materials in the peripheral zone also impede the introduction therein of additional materials, particularly liquids, to be mixed.
U.S. Pat. No. 3,256,181 to Zingg et al shows a mixer incorporating a centrifugal pump with a double-faced, shaft-mounted impeller whereby solid particulate and liquid components are initially commingled, as well as mixed, in the peripheral zone. U.S. Pat. Nos. 4,614,435 and 4,671,665 to McIntire teaches a machine for mixing solids and liquids including a solids slinger element mounted directly above a liquid impeller element, the slinger and impeller being mounted upon a vertical rotatable shaft. Solids dropped onto the central portion of the slinger are moved by centrifugal force to a peripheral zone and there mixed with a liquid pumped into the housing by the impeller. Initial commingling of solids with liquids occurs in the peripheral zone. U.S. Pat. No. 4,808,004 to McIntire et al shows a shaft-mounted rotating slinger for introducing solid particles into a blender, while a separate centrifugal pump is used to inject liquids into the blender housing and into the peripheral zone.
U.S. Pat. No. 4,834,542 to Sherwood discloses an apparatus similar to the devices taught by McIntire, with a liquid impeller and a solids slinger mounted upon a common shaft, and including a hopper for introducing particulates non-centrally to the slinger and a disturber element for creating a low-pressure mixing zone where the particulates are introduced.
Despite the efforts represented by the foregoing patents, the entire disclosures of which are incorporated herein by reference, a need remains for a double-faced impeller mixer which permits initial commingling of solids and liquids in a zone of reduced pressure, and yet exploits the beneficial mixing effects of a high pressure peripheral zone. There also remains a need for a centrifugal type blender with a slinger or thrower portion which utilizes gravity in part to promote movement of solid particles to a mixing zone, rather than relying exclusively upon centrifugal force to move solid particles. Against this background, and to meet the described need and to proffer other advantages over the known art, the following invention was developed.


A fault-tolerant actuator module, in a single containment shell, containing two actuator subsystems that are either asymmetrically or symmetrically laid out is provided. Fault tolerance in the actuators of the present invention is achieved by the employment of dual sets of equal resources. Dual resources are integrated into single modules, with each having the external appearance and functionality of a single set of resources.

The present invention relates generally to rotary actuators and more specifically to rotary actuators having improved fault-tolerance.
Rotary actuators are the most common drivers of our machines. The partial or complete failure of an actuator can cause a life threatening accident, result in costly downtime, or prevent the continuation of a critical long-duration process, such as micro-surgery. In certain applications, it is crucial that the actuator continue to function even in the event of a fault or failure in the system. Such a fault might occur, for example, in the electronics, wiring, sensors, prime mover, or gear train of the system.
Continued operation under a fault is especially desirable where long-duration missions are involved, where human life is at stake, or where a large economic loss would occur. Fault-tolerant designs have been developed incorporating excess actuators into the system in order to create an excess of inputs, thereby creating a redundant system. In such systems, this redundancy then necessitates that a huge number of decisions must be made in real time at the system level in order to get the whole system to reliably produce a desired output motion or force. Owing to inherent resulting output uncertainty, this approach is still largely a laboratory approach that is rarely used in industrial production systems.


A current mode power conversion system and method operates in cycles. Each cycle includes an on time and an off time. The system includes an inductor connected to store energy during the on time of each cycle and use the energy during the off time of each cycle. The system provides a stable output voltage and a maximum-limited output current to a load during constant load conditions. The system comprises a feedback control linearly operable so as to control the output voltage across the load during constant load conditions, and non-linearly operable so as to control the output voltage across the load during certain detected changes in load conditions as a function of the derivative of the current in the inductor so as to speed up the transient response of the power conversion system when a fault condition exists.

DC/DC converters have been popular in industry for many years. Current mode DC/DC power converters include various designs which have been used. Such designs include peak and valley current mode devices. These devices are turned on and off during each cycle at the frequency of operation. There are devices that operate so that either the "on" time (of each cycle) remains constant (on time control), or the off time (of each cycle) remains constant (off time control), i.e., control the duty cycle by controlling the on time or off time of each cycle of control.
These conventional systems normally include an energy storage device, usually in the form of an inductor, so that energy can be stored during the on time of each cycle and used during the off time of each cycle. The converter system is regulated usually by sensing the current through the inductor, not the current through the load. If there is a transient in the load, i.e., it is drawing either more or less current than it was, the converter wants to keep the load voltage constant, and must respond to the transient as quickly as possible. Because the converter senses the current information, it can provide accurate protection against over-current conditions. Converters can be peak or valley current architectures. Further, current mode converters are easy to compensate to insure a stable output when load conditions are stable, and therefore they are easy to use. Current mode controlled architectures provide a natural current limit and are stable over a wide range of input and output conditions. They are ideally suited for multiphase applications where current sharing and transient response is of greater importance. Increasing current limit beyond maximum load current allows headroom for improved response during transients at heavy load. This headroom however increases the size and rating requirement of the converter power components and leads to a reduced signal to noise ratio under nominal conditions.
Since current mode controlled DC/DC converters limit the output current, they thus act as a current source. During an output load change, initially the current is provided by output capacitors because no converter is fast enough for a sudden and rapid load change. The output will rise/fall depending on the difference between load and inductor current. The controller will sense this change in voltage and turn on the appropriate switch. In the case of the peak current mode controlled converter, the worse case happens when the output load increases right after the control switch has just turned off. The converter has to wait for the next clock pulse to turn on the control switch. For a sufficiently high bandwidth converter, this clock latency is the main reason for voltage droop during the transient response for this architecture. Similar latency issues exist in the other current mode architectures for different load transient conditions.

DC/DC power converter with feedback control operable in linear and non-linear modes


The present invention provides a method for preparing an ultra high molecular weight polyethylene (UHMWPE) composite material including the following steps: providing a substrate material having medical grade ultra high molecular weight polyethylene powders, drying the substrate material to obtain fully dried UHMWPE powders, and pressing the fully dried UHMWPE powders to form a UHMWPE board; immersing the UHMWPE board into a graphene oxide solution and performing an ultrasonic induction by an ultrasonic processor such that the graphene oxide solution infiltrates into the UHMWPE substrate to obtain an ultra high molecular weight polyethylene composite material with excellent biocompatibility and tribological properties. The graphene oxide can be adsorbed and evenly spread on the surface of UHMWPE substrate by ultrasonic induction to form a lubricating film which can effectively reduce wear.

With the rapid aging of the population, patients with bone and joint problems are increasing year by year. At the present, damage joint replacement is the common clinical treatment for patients with joint problem. Therefore, materials for joint replacement play the crucial role for the successful treatment. Ultra high molecular weight polyethylene (UHMWPE) is an ideal medical polymer material, which has been widely used in the field of artificial joint replacement due to its low friction coefficient, biocompatibility, excellent wear resistance and corrosion resistance. However, UHMWPE will be worn and oxidized seriously in the long-term usage, which will produce wear debris and lead to osteolysis, aseptic loosening and invalid in the end. Then, it is necessary to reimplant the joint, which will cause secondary injury to the patient. Therefore, in order to alleviate the pain of patients and improve the life cycle of UHMWPE, it is of great importance to further improve the bio-tribological properties of UHMWPE.
Graphene oxide (GO) has excellent mechanical properties and self-lubricating properties, which can effectively improve the wear resistance of the composite materials. It is an important material to enhance the bio-tribological properties of UHMWPE composite materials.
However, the conventional GO/UHMWPE composite materials are mostly prepared by mixing GO into UHMWPE substrate materials. Although the properties of the substrate materials are improved in some aspects, such as hydrophilic properties and wear properties, the improvement is not significant, and the mixed GO will reduce the bonding between the substrate materials, resulting in a serious decrease in the shear strength. Therefore, it is of great significance to improve the bio-tribological properties of UHMWPE composite materials by further increasing the penetration levels of GO into UHMWPE substrate without affecting the bonding strength between the substrate materials.

Method for preparing ultra high molecular weight polyethylene composite materials


Targeting agents such as transferrin and transcobalamin can be conjugated with anti-protozoan drugs for the treatment of protozoan infections. Any suitable anti-protozoan drug can be used, preferably the drug is selected from the group consisting of apoptosis inducing compounds, cytotoxic antibiotics, alkalating agents, plant toxins, and bacterial mutant toxins. The targeting agent is preferably coupled to the antiprotozoan drug by means of glutaraldehyde.

Protozoa are unicellular eukaryotic organisms that can infect and multiply in mammalian hosts. They may utilize more than one type of host, including insect hosts, during their life cycle. Parasitic protozoa account for a significant portion of all infectious diseases worldwide. Although the majority of protozoan infections occur in developing countries, these infections are seen increasingly in industrialized countries among immigrants and immunosuppressed or immunodeficient individuals. Commonly seen parasitic diseases include malaria, trypanosorriasis, and Chagas disease. The treatment of protozoan infections is problematic due to lack of effective chemotherapeutic agents which traverse the blood brain barrier, excessive toxicity of the therapeutic agents and increasingly widespread resistance to the therapeutic agents. Well known and presently used drugs for treating parasitic infections, caused by protozoa include the drugs melarsopral, eflornithine, chloroquine, quinine, mefloquine, amodiaquine, primaquine, pyrimethamine, sulfadoxine, sulfadiazine, trimethoprim, pentavalent antimony, pentamidine, amphotericin-B, rifampin, metronidazole, ketoconazole, benznidazole, nifurtimox, and halofantrinc.
Two common problems in treatments which involve drugs are drug-toxicity, which debilitates patients, and drug-resistance, which requires more drugs and thus amplifies the problem of drug-toxicity, often resulting in death. One way to solve the problem of drug-toxicity is to deliver drugs so they are targeted only to the infected cells or tissues. Many researchers are working to develop antibodies to deliver drugs, and this approach holds promise, but antibodies are not without problems. For example, they often cross-react with normal tissues, and they can damage blood vessels (e.g., vascular leak syndrome) and cause dangerous allergic reactions (e.g. anaphylaxis).
The treatment of specific cells by the delivery of drugs, including drugs that are toxic to such cells, is not new. U.S. Pat. Nos. 4,886,780; 4,895,714; 5,000,935; and 5,108,987 to Faulk and U.S. Pat. No. 4,590,001 to Stjernholm et. al., describe cytotoxic. or radioimaging materials conjugated to proteins, mainly to transferrin, as treatments for cancerous cells or for imaging cancerous cells.
It is known that stressed cells, such as, for example, human cells hosting a parasitic infection, call for an increased delivery of nutrients, such as iron, by presenting an increased number of receptors for nutrient carriers, such as transferrin in the case of iron. The increase in receptors for nutrient carriers in stressed cells is known to be relatively constant and orders of magnitude greater in number than in unstressed cells, which are known to show receptors intermittently and in relatively smaller numbers. The publications listed above, and others, disclose taking advantage of the increased number of receptors, especially for transferrin, presented by cancer containing cells to deliver imaging materials or drugs or both to the stressed cell.
No single study has asked if all stressed cells have up regulated transferrin receptors, or if all normal cells have down regulated transferrin receptors, but data from many quarters suggest that all normal cells have down regulated transferrin receptors. For example, immature erythrocytes (i.e., normoblasts and reticulocytes) have transferrin receptors on their surfaces, but mature erythrocytes do not (Lesley J, Hyman R, Schulte R and Trotter J. Expression of transferrin receptor on murine hematopoietic progenitors. Cell Immunol 1984; 83: 14–25). Circulating monocytes also do not have up regulated transferrin receptors (Testa U, Pelosi E and Peschle C. The transferrin receptor. Crit Rev Oncogen 1993; 4: 241–276), and macrophages, including Kupffer cells, acquire most of their iron by a transferrin-independent method of erythrophagocytosis (Bothwell T A, Charlton R W, Cook J D and Finch C A. Iron Metabolism in Man, Blackwell Scientific, Oxford, 1979). In fact, in vivo studies indicate that virtually no iron enters the reticuloendothelial system from plasma transferrin (for review, see Ponka P and Lok C N. The transferrin receptor: role in health and disease. Int J Biochem Cell Biol 1999; 31: 1111–1137.). Macrophage transferrin receptors are down regulated by cytokines such as gamma interferon (Hamilton T A, Gray P W and Adams D O. Expression of the transferrin receptor on murine peritoneal macrophages is modulated by in vitro treatment with interferon gamma Cell Immunol 1984; 89: 478–488.), presumably as a mechanism of iron-restriction to kill intracellular parasites (Byrd T F and Horowitz M A. Interferon gamma-activated human monocytes downregulate transferrin receptors and inhibit the intracellular multiplication of Legionella. pneumophila by limiting the availability of iron J Clin Invest 1989; 83: 1457–1465.).
In resting lymphocytes, not only are transferrin receptors down regulated, but the gene for transferrin receptor is not measurable (Kronke M, Leonard W, Depper. J M and Greene W C. Sequential expression of genes involved in human T lymphocyte growth and differentiation. J Exp Med 1985; 161: 1593–1598). In contrast, stimulated lymphocytes up-regulate transferrin receptors in late G1 (Galbraith R M and Galbraith G M. Expression of transferrin receptors on mitogen-stimulated human peripheral blood lymphocytes: relation to cellular activation and related metabolic events. Immunology 1983; 133: 703–710). Receptor expression occurs subsequent to expression of the c-myc proto-oncogene and following up-regulation of IL-2 receptor (Neckers L M and Cossman J. Transferrin receptor induction in mitogen-stimulated human T lymphocytes is required for DNA synthesis and cell division and is regulated by interleukin 2. Proc Nat Acad Sci USA 1983; 80: 3494–3498.), and is accompanied by a measurable increase in iron-regulatory protein binding activity (Testa U, Kuhn L, Petrini M, Quaranta M T, Pelosi E and Peschle C. Differential regulation of iron regulatory element-binding protein(s) in cell extracts of activated lymphocytes versus monocytes-macrophages. J Biol Chem 1991; 266: 3925–3930), which stabilizes transferrin receptor mRNA (Seiser C, Texieira S and Kuhn L C. Interleukin-2-dependent transcriptional and post-transcriptional regulation of transferrin receptor-mRNA. J Biol Chem 1993; 268: 13,074–13,080.). This is true for both T and B lymphocytes (Neckers L M, Yenokida G and James S P. The role of the transferrin receptor in human B lymphocyte activation. J Immunol 1984; 133: 2437–2441), and is an IL-2-dependent response (Neckers L M and Trepel J B. Transferrin-receptor expression and the control of cell growth Cancer Invest 1986; 4: 461–470).
Malaria
Approximately 40% of the world's population are at risk for malaria. That is, in excess of 2000 million people in about 100 countries are at risk (Gilles, 1991, World Health Organization, Geneva). Particularly affected are children in developing countries (Greenwood et al., Trans Soc Trop Med Hyg 1987; 81:478). For example, a million children die of malaria every year in sub-Saharan Africa (World Health Organization, 1974, Technical Report Series No. 537). The rise of travel, trade and tourism also has extended malaria into developed countries (Greenberg & Lobel, Ann Intern Med 1990; 113:326). These social and economic problems are compounded by the complexities of vector control and the problematic development of an effective malaria vaccine (Graves & Gelband, Cochrane Database of Systematic Reviews CD000129, 2000). Thus, anti-malarial drugs remain the bulwark of defense against malaria, but this is being eroded by the spreading emergence of drug resistant strains of Plasmodiurn falciparurn, causing safe, widely available and inexpensive drugs like chloroquine to be increasingly less effective (Clyde, Epidemiol Rev 1987; 9:219). Taken together, these observations-indicate a pressing need for new drug strategies in the war on malaria The present invention provides a new strategy for the design of anti-malarial drugs.
The Plasmodium falciparum parasite reproduces rapidly within red blood cells of its host. Red cells are invaded by the merozoite stage of the parasite, which matures into the trophozoite stage and sufficiently replicates its DNA to produce 32 daughter cells within 48 hours. Like all developing cells (Richardson & Ponka, Biochim Biophys Acta 1997; 1331:1), developing plasmodia require iron to promote the function of key enzymes, such as ribonucleotide reductase for DNA synthesis (Chitambar et al., Biochem J 2000; 345:681), and iron-dependent enzymes for pyrimidine synthesis, CO2 fixation and mitochondrial electron transport (Mabeza et al., Acta Haematol 1996; 95:78). The importance of iron in plasmodial development has been demonstrated in both in vitro Cabantchik et al., Acta Haematol 1996; 95:70) and in vivo (Pollack et al., Proc Soc Exp Biol Med 1987; 184:162) models in which growth of parasites is inhibited by iron chelation. The most widely studied iron chelator is deferoximine, which is a siderophore or chelator that tightly (i.e., affinity of 1031/M) binds iron (Peto & Thompson, Br J Haematol 1986; 63:273). Clinical studies of Zambian children with advanced cerebral malaria (e.g., comatose) have revealed that patients treated with a standard program of anti-malarial therapy plus deferoxamine (100 mg/kg/day) recovered more rapidly than patients who received the same program of anti-malarial therapy without deferoxarine (Gordeuk et al., N Engl J Med 1992; 327:1473).
In light of the key role played by iron in the growth and development of plasmodia, much research has focused on how plasmodia obtain iron, and whether the parasites can be killed by drugs that interfere with the metabolic pathways that are used to acquire iron. Conceptually, plasmodia can obtain iron either from within the red blood cells in which they reside, or from the patient's transferrin, which is the normal protein in blood that carries iron (Ponka & Lok, Int J Biochem Cell Biol 1999; 31:1111). There is little doubt that plasmodia are capable of obtaining iron from red blood cells (Hershko & Peto, J Exp Med 1988; 168:375). In order to obtain iron from the patient's transferrin, there must be transferrin receptors on red blood cells, but normal adult red blood cells do not manifest transferrin receptors (Richardson & Ponka, Biochim Biophys Acta 1997; 1331:1). However, malaria infected red blood cells bind transferrin (Pollack & Fleming, Br J Haematol 1984; 58:289), and data have been produced that have identified 102 kD (Haldar et al., Proc Natl Acad Sci USA 1986; 83:8565) and 93 kD (Rodriguez & Jungery, Nature 1986; 324:388) transferrin receptors in the plasma membranes of red blood cells infected with Plasmodium falciparum. Although these observations have been challenged (Pollack & Schnelle, Br J Haematol 1988; 68: 125), subsequent experiments have shown that the receptors are functional, inasmuch as they have been used to deliver an anti-plasmodial toxin to infected red cells, and such delivery was inhibited by antibody to transferrin (Surolia & Misquith, FEBS Letters 1996; 396:57).
Trypanosomiasis
Trypanosomiasis is a parasitic infection caused by trypanosomes, which are protozoans that are passed to human beings by the bite of an infected tsetse fly (Smith et al., Brit Med Bull 1998; 54:341). When introduced into patients, trypanosomes proliferate in blood and lymphatics, which is the first stage of disease; the second stage of disease develops when parasites traverse the blood-brain-barrier and cause neurological damage and lethargy, commonly known as sleeping sickness (Beutivoglio et al., Trends Neurosci 1994; 17:325). If untreated, trypanosomiasis in both humans and animals is a fatal disease (New York Times, May 21, 2000).
There are two clinical forms of infection that are caused by different trypanosome subspecies. First, Trypanosoma brucei gambiense causes a chronic disease that takes several years to reach advanced stage; second, Trypanosoma brucei rhodesiense causes an acute disease that is fatal within weeks; Both diseases are endemic in Africa, and infections with Trypanosoma brucei gambiense currently are epidemic, placing at risk 60 million people inhabiting 36 sub-Saharan countries (Barrett, Lancet 1999; 353:1113). In addition, trypanosomiasis is limited neither to Africa (Dissanaike, Celyon Med J 2000; 45:40) nor to humans (Karnau et al., Prevent Vet Med 2000; 44:231), and the economic impact of these diseases profoundly impact national economies (Bauer et al., Trop. Animal Hlth & Prod 1999; 31:89).
Diagnostic approaches to trypanosomiasis have been designed to identify the stage of disease in patients, for early infections limited to blood and lymphatics can be treated with less toxic drugs than later infections involving the central nervous system (Dumas & Buiteille, Med Trop 1997; 57:65). There are currently two drugs for treatment of central nervous system infections (i.e., sleeping sickness). The least expensive, most available and most toxic is melarsopral, which is an arsenical drug that induces a fatal encepholopathy in 5–7% of recipients (Harrison et al., Am J Trop Med Hyg 1997; 56:632). These problems are compounded by drug resistance, low response rates and relapse rates as high as 10% (Pepin & Milard, Adv Parasitol 1994; 33:1). A less toxic, more expensive and difficult to acquire alternative to melarsopral is eflornithine, which is an ornithine decarboxylase inhibitor that impedes polyamine synthesis (Sjoerdsma & Schechter, Lancet 1999; 354:254), but this molecule presently is being marketed as an expensive anti-cancer drug.
There also currently are two drugs available for treatment of early stage infections. One of these, pentamidine, was developed in 1941, and the other, suramin, was developed in 1920. Pentamidine also is effective in Pneumocystis carinii infections common in AIDS patients, and it is about 4-fold more expensive than suramin, which for the moment is used only in trypanosomiasis. There are other compounds with trypanocidal activity (Enanga et al., Trop Med Int Health 1998; 3:736), but most of these do not cross the blood-brain-barrier and thus are of limited usefulness in infections of the central nervous system.
The targeted delivery of drugs has the advantage of increasing efficacy while using less drug, thereby decreasing toxicity and causing less damage to normal cells, all of which effectively decrease costs and increase the quality of patient care. Targeted delivery also avoids drug-resistance, which is activated by the non-specific entrance of drugs into cells (Marbeuf-Gueye C, Ettori D, Priebe W, Kozlowski H and Gamier-Suillerot A. Correlation between the kinetics of anthracycline uptake and the resistance factor,in cancer cells expressing the multidrug resistance protein or the P-glycoprotein. Biochem Biophy Acta 1999; 1450: 374–384). Because transferrin-drug conjugates enter cells specifically by employing a receptor-specific pathway (Klausner R D, vanReuswoude J, Ashwell G, Kempf C, Schechter A N, Dean A and Bridges K. Receptor-mediated endocytosis of transferrin in K562 cells. J Biol Chem, 1983; 258: 4715–4724.; Berczi A,.Ruthner M, Szuts V, Fritzer M, Schweinzer E and Goldenberg H. Influence of conjugation of doxorubicin to transferrin on the iron uptake by K562 cells via receptor-mediated endocytosis. Euro J Biochem 1993; 213: 427–436.), they are trafficked around drug-resistance mechanisms, such as efflux pumps in resistant cells.
There exists an unfulfilled need for an inexpensive and effective agent for selectively targeting and eliminating cells diseased by protozoan parasitic invasion

Targeted delivery of drugs for the treatment of parasitic infections


According to one general aspect, an apparatus may include a latch circuit configured to, depending in part upon a state of an enable signal, substantially pass the first clock signal to an output signal. The latch circuit may include at least two transistors configured to essentially perform a NAND function and controlled by a second clock signal, wherein the at least two transistors are configured to alter the timing of the substantial passing of the first clock signal to the output signal.

Clock gating is a popular technique used in many synchronous circuits for reducing dynamic power dissipation. Clock gating saves power by adding more logic to a circuit to prune the clock tree. Pruning the clock disables portions of the circuitry so that the flip-flops in them do not have to switch states. Switching states consumes power. When not being switched, the switching power consumption goes to zero, and only leakage currents are incurred.
In electronics, a flip-flop is a circuit that has two stable states and can be used to store state information. A flip-flop is a bi-stable multi-vibrator. The circuit can be made to change state by signals applied to one or more control inputs and will have one or two outputs. It is the basic storage element in sequential logic. Flip-flops and latches are fundamental building blocks of digital electronics systems used in computers, communications, and many other types of systems.

Integrated clock gater latch structures with adjustable output reset


An on-spot selectively activated hydrophobic slide/microarray. The preparation method relates to a hydrophobic copolymer prepared by blending, grafting or co-polymerization of a hydrophobic material and a compound bearing a functional group protected by a protecting group, wherein the functional group is imide or cyclic amide, and the protecting group is a photo acid group such as a tosyloxy group. The hydrophobic copolymer coated on a substrate is then subjected to selective photolithographical activation so that the slide will have functional active copolymer spots separated by inactive copolymers. The resulting slide is suitable for the preparation of high-density and high-efficiency bio-chip/microarray.

1. Field of the Invention
The present invention relates to an on-spot selectively activated hydrophobic slide/microarray and the preparation method thereof. More particularly, it relates to a hydrophobic copolymer prepared by blending, grafting or co-polymerization of a hydrophobic material and a compound bearing functional groups protected by a protecting group. The hydrophobic copolymer is coated on a substrate and subjected to selective photolithographical activation to form an on-spot selectively activated hydrophobic slide. The slide can then be used to produce an on-spot selectively activated hydrophobic microarray.
2. Description of the Related Arts
In current biochip and bio-microarray technology, most preparation methods involve the treatment of a matrix surface with silanization, followed by crosslinking reaction with biomaterials. In the silanization treatment, the surface of the substrate is activated based on its material, and then treated by a hydrophilic silane such as APTES (amino-propyl-tetraethoxy-silane). Afterwards, the crosslinking reaction is performed via a crosslinker such as glutaraldehyde to immobilize biomaterials on the substrate. The shortcomings of this method include substrate dependence, long reaction time, poor homogeneity, low reaction efficiency, and the resulting low activity for the immobilized biomaterials. Moreover, the prepared covalent bonding surface is hydrophilic, which facilitates crossover and contamination among spots when the hydrophilic surface is used for a high-density microarray.
U.S. Pat. No. 5,837,860 and WO 98/39481 disclose the treatment of glass or silicon wafer with hydrophobic silane such as mercapto-silane, and the immobilization of nucleic acid probes thereon. The method involves treating a substrate surface so that mercapto-groups (HS-) with hydrophobicity are covalently bonded thereon. The hydrophobic property is suitable for the immobilization of nucleic acids/nucleotides in high density. The method, however, requires the modification of the biomaterials to bear mercapto-groups, thereby forming disulfide bonds between the modified biomaterials and matrix surface. Blanchar, A. P. et al. (Biosensors and Bioelectronics, 1996, 11(6/7): 687–690) discloses coating photoresists onto a substrate and then development using the micro-electromechanical mask to form on-spot hydrophilic spots, wherein the region outside of the spots is hydrophobic. The preparation of high-density nucleic acid probe microarrays and in situ synthesis is carried out on this treated surface.
In this prior art, blending, grafting or co-polymerization of a hydrophobic material and a compound bearing functional groups such as imide, cyclic amide, and to prepare a hydrophobic copolymer is not disclosed. Further, the application of the prepared hydrophobic copolymer onto an organic or inorganic substrate to form an on-spot hydrophilic enhanced slide is also not disclosed.

On-spot selectively activated hydrophobic slide and preparation thereof