A non-volatile transistor memory array has individual cells with a current injector and a non-volatile memory transistor. Injector current gives rise to charged particles that can be stored in the memory transistor by tunneling. When a row of the array is activated by a word line, the active row has current injectors ready to operate if program line voltages are appropriate to cause charge storage in a memory cell, while a cell in an adjacent row be erased by charge being driven from a memory transistor. A series of conductive plates are arranged over the word line, with each plate having a pair of oppositely extending tangs, one causing programming of a cell in a first row and another causing erasing of a cell in another row.

Impact ionization has been known for several years. U.S. Pat. No. 4,432,075 to B. Eitan and U.S. Pat. No. 4,821,236 to Hayashi et al. describe an EEPROM transistor adjacent to a charge generator, creating a substrate current near the EEPROM, creating excess charge or holes, resembling space charge, near subsurface electrodes of the EEPROM. Assume that the holes are generated and accelerated toward one of the electrodes of the EEPROM. Resulting secondary electrons are sufficiently energetic to penetrate gate oxide over the substrate and become injected into a conductive floating gate. For very small EEPROMs, the floating gate becomes charged by band-to-band tunneling, a situation which eliminates the need for a control gate over the floating gate.
U.S. Pat. No. 5,126,967 and U.S. Pat. No. 4,890,259 to R. Sinks describe a memory array made of non-volatile transistors that can store analog waveforms.
The ability of EEPROM transistors to directly record analog waveforms, without A-to-D conversion, gives rise to new applications, such as use in neural networks. This has been pointed out in U.S. Pat. No. 6,125,053 where C. Dioris and C. Mead describe use of EEPROMs storing variable amounts of charge generated by impact ionization to represent an analog value. This is in contrast to a conventional EEPROM where a floating gate either stores charge or does not store charge, thereby indicating a digital value. In the '053 patent, an EEPROM is described that permits simultaneous writing and reading.
An analogous problem is simultaneous programming and erasing operations in an array. An object of the invention was to devise a memory array that has simultaneous programming of one memory region and erasing of another memory region.

Non-volatile memory array with simultaneous write and erase feature


A microphone assembly includes a substrate defining a port, a MEMS transducer, a guard ring, and a can. The MEMS transducer is coupled to the substrate such that the MEMS transducer is positioned over the port. The guard ring is coupled to the substrate and surrounds the MEMS transducer. The guard ring includes a plurality of edges that further includes a first edge and an opposing second edge. A portion of the first edge and a portion of the second edge have a reduced thickness relative to adjacent ones of the plurality of edges. The can is coupled to the guard ring such that the substrate and the can cooperatively define an interior cavity.

Compact components are desirable when building high-performance, high-density devices such as mobile communication devices, portable music players, and other portable electronic devices. One solution for providing high quality, compact devices is to use microelectromechanical systems (MEMS).
For example, microphone assemblies for many portable electronic devices include MEMS acoustic transducers, which convert acoustic energy into an electrical signal. The MEMS acoustic transducer includes a silicon die that is mounted onto a printed circuit board (PCB) to form the microphone assembly. Although the silicon die is small, existing manufacturing processes for these microphone assemblies are limited in terms of the overall size of the silicon die that can be accommodated within a given microphone package.

Single line axis solder dispense process for a MEMS device


A method and apparatus for increasing the capacity of wireless broadcast communications system from a central studio to a plurality of users in a service area is disclosed. Given a source signal whose high information rate exceeds the practical information carrying capacity of the available broadcast channel bandwidth, the invention increases the effective capacity of the broadcast system to effectively communicate such a source signal. The high-rate signal is split into several low-rate signals such that each can be accommodated within the allocated bandwidth. These low-rate signals are transmitted from spatially separated transmitters, all radiating into the service area in the same frequency channel. Each receiver uses a plurality of antennas to receive these multiple cochannel signals that arrive from different directions-of-arrival. The receiver exploits the directions-of-arrival differences of these cochannel signals to separate them into the individually transmitted signals. The separated signals are then demodulated to extract the information signals which are then combined to obtain the original high-rate source signal. Thus, the broadcast information capacity can be increased several-fold.

1. Field of the Invention
This invention relates to the field of wireless broadcast of information to a multiplicity of receivers, and in particular to a method and apparatus for increasing the effective information transmission bandwidth or equivalently channel capacity by means of source signal splitting, spatially distributed cochannel transmission, directionally selective reception, and source signal recombination.
1. Prior Art
In wireless broadcast systems, information generated by a source is transmitted by wireless means to a plurality of receivers within a particular service area. The transmission of such information over a fixed time interval requires a finite amount of (frequency) bandwidth, and in current state-of-the-art, transmission of information from different sources must occur in different frequency bands (channels). Since there are quite a few services (e.g., television (TV), FM radio, private and public mobile communications, etc.) competing for a finite amount of available spectrum, the amount of spectrum which can be allocated to each channel is severely limited. Innovative means for using the available spectrum more efficiently are of great value. In current state-of-the-art systems such as broadcast television, a suitably modulated signal is transmitted from a single tower centrally located in the service area and propagate to receiving stations in the service area surrounding the transmitter. The information transmission rate achievable by such broadcast transmission is constrained by the allocated bandwidth (C. P. Sandbank, "Digital Television", John Wiley, 1990 and W. F. Schreiber, "Fundamentals of Electronic Imaging: Some Aspects of Image Processing", Springer Verlag, 1991).
Due to attenuation suffered by signals in wireless propagation, the same frequency channel can be reused in a different geographical service area. Allowable interference levels determine the maximum transmit power at each location, as a well as the minimum separation between service areas using the same channels. Currently, within a service area, the rate at which information can be transferred to the receivers is limited by the fact that use of any channel is on a one-at-a-time basis. Simultaneous transmission of independent signals requires the use of separate channels. The current invention is a new method for increasing the capacity of a broadcast channel several fold by employing directional channels. Directional channels are realized by spatially distributing signals to be transmitted, and employing directionally sensitive receivers, a concept unique to this invention.
In prior art, increasing the capacity of point-to-point communication links has been proposed by S. Anderson, et al. "An Adaptive Array for Mobile Communications Systems", IEEE Trans. Veh. Technology, Vol.40. February 1991, pp. 230-236, and S. C. Swales, et al. "The Realization of a Multi-beam Antenna for Cellular Mobile Land Radio System", Mobile Radio and Personal Communications Conf., U.K., December, 1989, pp. 341-348. These papers addressed means for increasing the number of simultaneous users of a wireless communication system by allowing more than one user to use the same frequency, and exploiting the differences in directions-of-arrival at the receive antenna array to separate the different signals. However, they do not address the problem of increasing capacity in a broadcast channel.
Also in prior art, increasing capacity of point-to-point communication links using directional channels was claimed in R. Roy, et al., "Methods for Estimating Signal Source Locations and Signal Parameters Using an Array of Signal Sensor Pairs," U.S. Pat. No. 4,750,147, March 1985, U.S. Cl. 364-800, and R. Roy, et al., "Methods and Arrangements for Signal Reception and Parameter Estimation," U.S. Pat. No. 4,968,732, July 1987, U.S. Cl. 364-460, and in a recent patent filing, R. Roy, et al., "Spatial Division Multiple Access Wireless Communication Systems", U.S. patent application Ser. No. 806,695, filed Dec. 12, 1991. Therein, no reference is made to the broadcast problem, and increasing broadcast channel capacity is not claimed in these patents. Moreover, in the first two referenced patents, arrays used therein are required to possess a special structure, i.e., sensors occur in pairs of identical elements.
Spatial processing has also been used in the context of spatial diversity techniques wherein multiple antennas that are employed for reception of broadcast signals are scanned for the strongest signal and its output chosen for further processing, or some method for combining the such outputs is applied. Though this leads to a improvement in the quality of the received signal, there is no increase in system capacity.
In prior art, increasing capacity of TV broadcast systems and in particular for HDTV where a severe bandwidth constraint exists, several patents have proposed use of plural/multiple channels to increase information transmission: M. A. Isnardi, et al., "Extended Definition Widescreen Television System Using Plural Signal Transmission" U.S. Pat. No. 4,888,641, October 1988, US Cl. 358-141; T. Okano, "Multichannel Video Signal Transmission/Reproduction System" Japan Patent 5,041,909, December 1987, US Cl. 358-146; E. L. J. Fonsalves, "System of Transmitting High-Definition Television Pictures via a Relatively Narrow Passband Channel, and Also a Transmitter and Receiver Suitable for the System", U.S. Pat. No. 4,935,813, March 1988, U.S. CL. 358-138, W. F. Schreiber. "Definition Television Systems" U.S. Pat. No. 5,021,882, April. 1989, US Cl. 358-141. In W. F. Schreiber, "Reliable Television Transmission Through Analog Channels", U.S. Pat. No. 5,040,211 October 1988, US Cl. 380-14, a system for spatially processing the acquired TV image, dividing it into spatiotemporal frequency components, followed by coding of the information prior to transmission is disclosed. However, none of this prior art mentions the use of spatial processing or directional channels to increase capacity. The word channel in all the above cases refers to frequency channels, and multiple channels require additional spectrum. Reuse of the same frequency channel by transmitters at different spatial locations is unique to this invention.

Increasing capacity in wireless broadcast systems using distributed transmission/directional reception (DTDR)

The Board of Trustees of the Leland Stanford Junior University


This application provides a maximum power point tracking method and a device, to improve conversion efficiency of a control device in a photovoltaic power generation system, and reduce a loss of a power generation capacity. The method includes: adjusting, by the control device, an input voltage of the control device, where the input voltage is generated by one or more of the photovoltaic module and is transmitted to the control device; determining whether a difference between a first input power and a second input power of the control device is less than or equal to a setpoint, adjusting the input voltage of the control device according to the first input power and the second input power.

Solar energy is a massive renewable resource, and radiant energy that reaches the surface of the earth every day is equivalent to energy generated when hundreds of millions of barrels of oil are burnt, and development and use of solar energy cause little pollution to the environment, and even does not pollute the environment. Photovoltaic (PV) power generation is a most common manner of using solar energy, can directly convert photon energy into electric energy, and has advantages such as high reliability, a long service life, and being environment-friendly.
A photovoltaic array in a photovoltaic power generation system is installed outdoors, and is affected by external factors such as light intensity and environment. For example, a photovoltaic module in the photovoltaic array is blocked, and an output power of the photovoltaic module varies. In an existing technology, a converter is added to the photovoltaic module in the photovoltaic array, and a maximum power point tracking (MPPT) method is used in an inverter connected to the photovoltaic module. To be specific, an output voltage of the photovoltaic module is perturbed, output powers of the photovoltaic module that are obtained before and after the perturbation are compared, and when the output powers of the photovoltaic module that are obtained before and after the perturbation are the same, the output power of the photovoltaic module is a maximum power point of the photovoltaic module, and the photovoltaic module is kept working at the maximum power point, to improve efficiency of the photovoltaic power generation system to the greatest extent.
However, for a scenario in which a converter is configured in each photovoltaic module in a photovoltaic array, introduction of the converter changes an output characteristic of the original photovoltaic module. An output characteristic of the converter includes a constant power interval. Although the converter can be controlled to work in the constant power interval when an inverter uses the MPPT method, and in this case, the photovoltaic module connected to the converter works at a maximum power point, an output voltage of the converter is unstable, that is, an input voltage of the inverter is unstable. When the inverter works at a low voltage and high current input, conversion efficiency of both the converter and the inverter decreases, leading to a loss of a power generation capacity.

Maximum power point tracking method and device


A method for operating a TSN-enabled network coupling element, in particular, a TSN bridge, which is designed to receive redundant data packets. The method includes ascertaining at least one number of expected, non-received data packets via the TSN-enabled network coupling element, and transmitting the ascertained number of expected, non-received data packets from the TSN-enabled network coupling element to a control instance.

The present invention relates to a TSN-enabled network coupling element, in particular, to a TSN bridge, and to a method for operating a TSN-enabled network coupling element, in particular, a TSN bridge, which is designed to receive redundant data packets.
The present invention further relates to a control system and to a method for operating a control instance in a TSN communication system.

Method for operating TSN-enabled network coupling elements


A control device for a lockup clutch is provided in which when control region determination device determines that a vehicle speed and an opening degree of an accelerator pedal are in the tight region of the lockup clutch, even if the water temperature of cooling water of the or the oil temperature of hydraulic oil of the transmission is less than a predetermined temperature, engagement permission device permits engagement of the lockup clutch. It is therefore possible to improve the fuel economy of the vehicle by increasing the frequency of engagement of the lockup clutch without affecting the function of the lockup clutch. The control device even functions when the lockup clutch is engaged at low temperatures, when the engagement responsiveness is low, because the oil temperature of the hydraulic oil is low and the viscosity is high.

Engagement of a lockup clutch is normally permitted when the water temperature of cooling water of an engine is at least 80° C. since, if the lockup clutch is engaged when the oil temperature of hydraulic oil of a transmission is low and the viscosity is high, there are problems such as vibration being generated due to engagement shock; an arrangement in which engagement of a lockup clutch is permitted when the water temperature is less than 80° C. but at least 60° C. and the oil temperature is at least 50° C. to thus increase the frequency of engagement of the lockup clutch and improve the fuel economy is known from Patent Document 1 below.


A visible laser beam scanned by a galvano-scanner system is aligned at each of positioning points on the top surface of a master work by manual operation to record sensor position signals of position sensors on galvano-scanners. The sensor position signals on each positioning point are recorded to create a drive pattern in accordance with recorded sensor position signals. The drive pattern no longer has optics system error sources including focus error and attachment error as well as errors caused by scale, offset and the like, also eliminating the need for entering a distance as far as the top surface of the work. Therefore, the drive pattern with error components removed can be created with ease.

A galvano-scanner system is used to scan a laser beam according to a predetermined drive pattern in a laser processing device or a similar device. For example, in a laser marking device, there is provided a galvano-scanner system comprising an x-axis galvano-scanner and a y-axis galvano-scanner, a laser beam emitted from a laser beam source is two-dimensionally scanned by the scanners along a surface of a work according to a predetermined drive pattern, and a predetermined marking is applied to the work surface.
A drive pattern input command for a conventional galvano-scanner system is created by entering, in a manner similar to that for a timing chart, coordinates data representing a plurality of positioning points for defining the drive pattern, a sequence of each of the positioning points, and the speed of scan between each of the positioning points, using an higher-level device provided with a PC for controlling the galvano-scanner system; then adding a large amount of information that has been designed in advance, including the distance to a work surface, data for correcting distortion by an optics system, and response characteristics of the galvano-scanner. Therefore, in order to create a drive pattern input command, it is necessary to enter a large amount of information, and to set the information in advance. Therefore, creation of a drive pattern input command is time-consuming and requires a certain amount of preparation time and relevant expertise.
There is disclosed, in patent reference 1, a laser marking device provided with a function of projecting, using a guide laser beam, a guide image onto a work via a galvano-mirror, the guide image following a required pattern of printing. In the laser marking device, the galvano-mirror is caused to turn according to the same coordinates data as that used during a printing operation, a point of irradiation of the guide laser beam is thereby scanned on the work, and the print pattern guide image is projected on a surface of the work. An error between a position of guide image projection and a desired position on the work is thereby identified, making it possible to perform print position correction before printing commences. Therefore, in contrast to an instance in which actual printing is performed on a sample work and print position correction is performed, there is no need to make a sample work available, and print position correction can be performed with relative ease.    [Patent reference 1] JP-A 2003-220485

Method for creating drive pattern for galvano-scanner system


Novel phosphorus element-containing epoxy resin compositions and novel phosphorus-element containing epoxy resin compositions based on an isomeric mixture of tris(2-hydroxyphenyl)-phosphine oxide compounds including non-halogenated, ignition resistant epoxy resin formulations. The ignition resistant epoxy resin formulations are advantageously used for making laminates for printed wiring boards and composite materials.

This invention relates to new crosslinking agents for epoxy resin compositions, more particularly to phosphorus element-containing compounds useful as crosslinking agents for epoxy resin compositions to yield non-halogenated, ignition resistant phosphorus element-containing epoxy resin formulations. Even more particularly, the new phosphorus element-containing crosslinking agents of the present invention are based on isomeric mixtures of tris(2-hydroxyphenyl)phosphine oxides having the following general chemical structure of Formula I:
wherein R may be independently a hydrogen or a C1-C10 alkyl group such as methyl, ethyl, propyl, butyl, etc. The flame retardant epoxy resin formulations of this invention are advantageously used for making laminates for printed wiring boards and composite materials.
It is known to make electrical laminates and other composites from a fibrous reinforcement and an epoxy-containing matrix resin. Examples of suitable processes usually contain the following steps:
(1) an epoxy-containing formulation is applied to or impregnated into a substrate by rolling, dipping, spraying, other known techniques and/or combinations thereof. The substrate is typically a woven or nonwoven fiber mat containing, for instance, glass fibers or paper.
(2) The impregnated substrate is xe2x80x9cB-stagedxe2x80x9d by heating at a temperature sufficient to draw off solvent in the epoxy formulation and optionally to partially cure the epoxy formulation, so that the impregnated substrate can be handled easily. The xe2x80x9cB-stagingxe2x80x9d step is usually carried out at a temperature of from 90xc2x0 C. to 210xc2x0 C. and for a time of from 1 minute to 15 minutes. The impregnated substrate that results from B-staging is called a xe2x80x9cprepregxe2x80x9d. The temperature is most commonly 100xc2x0 C. for composites and 130xc2x0 C. to 200xc2x0 C. for electrical laminates.
(3) One or more sheets of prepreg are stacked or laid up in alternating layers with one or more sheets of a conductive material, such as copper foil, if an electrical laminate is desired.
(4) The laid-up sheets are pressed at high temperature and pressure for a time sufficient to cure the resin and form a laminate. The temperature of this lamination step is usually between 100xc2x0 C. and 230xc2x0 C., and is most often between 165xc2x0 C. and 190xc2x0 C. The lamination step may also be carried out in two or more stages, such as a first stage between 100xc2x0 C. and 150xc2x0 C. and a second stage at between 165xc2x0 C. and 190xc2x0 C. The pressure is usually between 50 N/cm2 and 500 N/cm2. The lamination step is usually carried out for a time of from 1 to 200 minutes, and most often for 45 to 90 minutes. The lamination step may optionally be carried out at higher temperatures for shorter times (such as in continuous lamination processes) or for longer times at lower temperatures (such as in low energy press processes).
(5) Optionally, the resulting laminate, for example a copper-clad laminate, may be post-treated by heating for a time at high temperature and ambient pressure. The temperature of post-treatment is usually between 120xc2x0 C. and 250xc2x0 C. The post-treatment time usually is between 30 minutes and 12 hours.
It is conventional in the preparation of epoxy-containing laminates to incorporate into the epoxy resin composition various additives to improve the flame-retardancy of the resulting laminate. Many types of flame retardant additives have been suggested, but the additives which are most widely used commercially are halogen-containing additives, such as tetrabromo-diphenylolpropane, or epoxy resins prepared by reacting diglycidyl ether of bisphenol-A with tetrabromodiphenylolpropane. Typically, in order to reach the desired fire retardancy level (V-0 in the standard xe2x80x9cUnderwriters Laboratoryxe2x80x9d test method UL 94), levels of such bromine-containing flame retardant additives are required which provide a bromine content of from 10 wt % to 25 wt % based on the total polymer weight in the product.
Although halogen-containing fire-retardant additives such as tetrabromodiphenylolpropane are effective, they are considered by some to be undesirable from an environmental standpoint, and in recent years there has been increasing interest in the formulation of halogen-free epoxy resins, which are able to meet the fire retardancy requirements.
Proposals have been made to use phosphorus-based flame retardants instead of halogenated fire retardants in epoxy resin formulations as described in, for example, EP A 0384939, EP A 0384940, EP A 0408990, DE A 4308184, DE A 4308185, DE A 4308187, WO A 96/07685, and WO A 96/07686. In these formulations a phosphorus flame retardant is pre-reacted with an epoxy resin to form a di- or multifunctional epoxy resin which is then cured with an amino cross-linker such as dicyandiamide, sulfanilamide, or some other nitrogen element-containing cross-linker to form the network.
There are some commercially available phosphorus-based fire retardant additives which may be useful for replacing halogen-containing fire-retardant additives. For example, Amgard(trademark) V19 and Antiblaze(trademark) 1045 (previously Amgard(trademark) P45) supplied by Albright and Wilson Ltd, United Kingdom, are commercially available phosphonic acid ester fire retardant materials. These phosphonic acid esters, may be solids or liquids.
Alkyl and aryl substituted phosphonic acid esters are compatible with epoxy resins. In particular lower (i.e., C1-C4) alkyl esters of phosphonic acid are of value because they contain a high proportion of phosphorus, and are thus able to impart good fire retardant properties upon resins in which they are incorporated. However, the phosphonic acid esters are not satisfactory as a substitute for halogenated flame retardants in epoxy resins for the production of electrical laminates, because the use of phosphonic acid esters in amounts sufficient to provide the necessary flame retardancy increases the tendency of the resulting cured epoxy resin to absorb moisture. The moisture absorbency of the cured laminate board is very significant, because laminates containing high levels of moisture tend to blister and fail, when introduced to a bath of liquid solder at temperatures around 260xc2x0 C., a typical step in the manufacture of printed wiring boards.
Another system, which utilizes a phosphorus-based flame retardant, is described in EP A 0754728. EP A 0754728 describes the production of a flame retardant epoxy resin system by blending an epoxy resin with a cyclic phosphonate as a flame retardant and incorporating the cyclic phosphonate into the cured resin. The epoxide resin and phosphonate mixture is crosslinked with a polyamine such as triethylamine, tetra amine, polyamido amines, multi basic acids or their anhydrides for example phthalic anhydride or hexahydrophthalic anhydride. EP A 0,754,728 indicates that large quantities, such as in excess of 18 wt %, of the phosphorus additive are needed in order for the resin system to meet UL 94 V-0.
WO 99/00451 discloses flame retardant epoxy resin compositions utilizing phosphonic acid esters. WO 99/00451 discloses the reaction of a phosphonic acid ester with an epoxy resin in the presence of a catalyst and a nitrogen-containing crosslinking agent. The crosslinking agent has an amine functionality of at least 2 and is preferably dicyandiamide. The epoxy resins described in WO 99/00451 have improved flame retardant properties at low levels of phosphonic acid ester flame retardant. However, there is still a need in the industry for a flame retardant epoxy resin with improved Tg and flame retardant properties.
As aforementioned, halogen-containing phenol compounds such as tetrabromobisphenol-A (TBBA) are well known materials used in epoxy resins, specifically for use in the manufacture of FR-4 laminates for printed circuit boards. Halogen-containing compounds, specifically bromine-containing materials have the disadvantages of corrosive acidic components, e.g. HBr, released at high temperatures. It would be desirous to provide a non-halogenated material as a fire retardant additive to replace halogen-contaning phenol compounds such as TBBA.
The prior art describes the use of certain phosphorus element-containing compounds as crosslinking or curing agents for use with epoxy resins as a way to introduce a phosphorus element into epoxy resin systems. For example, U.S. Pat. Nos. 4,973,631 and 5,086,156 describe the use of difunctional phosphine oxide crosslinkers such as a triphenyl phosphine oxide epoxy curing agent and a trihydrocarbyl phosphine oxide epoxy curing agent having the following chemical structural formula:
wherein Ar is an phenyl ring and the X moieties have an active hydrogen and include an amine, hydroxy, carboxy, anhydride and thiol moieties.
JP 61,134,395 [86,134,395] teaches the use of tris(3-hydroxyphenyl)phosphine oxide having the following chemical structural formula:
as a crosslinking agent for epoxy resins.
The above-mentioned prior art compositions are not easily prepared and require exotic preparation procedures. It would be advantageous to provide a compound that can be derived from practical, industrial scale raw materials; and thus, would offer an economic advantage over the prior art processes.
The prior art describes the use of phosphates [OP(OR)3] and other compounds with Pxe2x80x94Oxe2x80x94C units in epoxy resin formulations. Such resins do not provide a satisfactory resistance to water uptake. It would be desirous to provide compounds such as triarylphosphine oxides which do not contain Pxe2x80x94Oxe2x80x94C bonds, and therefore, do not suffer the disadvantages of the prior art compounds having Pxe2x80x94Oxe2x80x94C units. It would be desirous to provide phosphorus compounds with Pxe2x80x94C linkages having superior resistance to water uptake when compared to phosphorus compounds with Pxe2x80x94Oxe2x80x94C units.
Phosphorus-containing compounds have been used heretofore in a variety of epoxy-based polymer systems including for example FR-4 laminates for printed circuit boards, container coatings, as well as high-molecular weight epoxy-based thermoplastics. A driving force for this work has been the search for non-halogenated alternatives to brominated epoxy resins. For a variety of reasons, brominated flame retardants have been deemed environmentally unsound and the use of brominated flame retardants in flame retardant epoxy resins applications has been continually threatened by legislation. Thus, there is a need to address this issue.
Commercially available non-brominated flame retardants have been used as replacements for terabromobisphenol-A (TBBA) in FR-4 laminates for printed circuit boards. Although most of these materials are found to meet the requirements for ignition and heat resistance, excessive moisture uptake in the board is found to be the main problem with their use. The presence of excess moisture cause the laminate boards to fail blister resistance testing. Phosphorus-containing species (phosphates, phosphonates, and phosphoramides) that contained Pxe2x80x94O and Pxe2x80x94N bonds, are believed to be the cause of excessive moisture uptake due to their polarity. Thus, it is desired to provide materials that contain Pxe2x80x94C bonds instead of Pxe2x80x94O or Pxe2x80x94N bonds in FR-4 laminate applications. It would be advantageous if such materials would reduce the amount of water absorbed by the finished laminate board. It is desired to provide compounds, which improve resistance to moisture uptake in the laminate boards, while maintaining the requirements of excellent Tg and ignition resistance.
The present invention is directed to epoxy resins which meet the desirable standards of fire retardancy without the need for halogen-containing flame retardants, or at least employing significantly lower levels of such halogen-containing flame retardants than is conventional in the art.
One aspect of the present invention is directed to new phosphorus element-containing crosslinking agents for epoxy resin compositions, more particularly crosslinking agents based on an isomeric mixture of two or more isomers of tris(2-hydroxyphenyl)phosphine oxides having the general chemical structure of Formula I as follows:
wherein R is independently a hydrogen or a C1-C10 alkyl group such as methyl, ethyl, propyl, butyl, etc.
Another aspect of the present invention is directed to curable epoxy resin compositions containing a curable epoxy resin and, as a phosphorus element-containing crosslinking agent, an effective curing amount of a tris(2-hydroxyphenyl)phosphine oxide having the general chemical structure of Formula I as follows:
wherein R is independently a hydrogen or a C1-C10 alkyl group such as methyl, ethyl, propyl, butyl, etc.
Yet another aspect of the present invention is directed to preparing a non-halogenated, ignition resistant epoxy resin formulation useful for making laminates for printed wiring boards and composite materials using the above phosphorus element-containing crosslinking agent of Formula I.
Hydroxyphenylphosphine oxides, such as those having the above general Formula I, which contain less hydrophilic phosphorus-phenyl units, are advantageously used for the synthesis of epoxy-based thermosets. Compounds of Formula I can be incorporated into epoxy-based polymers via covalent linkages. Improvements in glass transition temperatures and ignition resistance are realized when the resultant phosphorus-containing polymers are compared to conventional bisphenol-A based epoxy thermophaucs. The pbenol-functionalized phosphine oxide species of the present invention may be useful as replacements for tetrabromobisphenol-A in FR-4 laminates applications.
It is an objective of the present invention to provide a cross-linking agent which yields superior performance when compared to the previously known commercially available non-halogenated materials.
Still another aspect of the present invention is directed to a compound which ncludes the glycidyl ether derivatives of Formula I, shown as the following chemical tructural Formula V:
wherein R is as defined above.
Yet another aspect of the present invention is directed to epoxy vinyl ester resins produced by reacting the compound of Formula V above with carboxylic acids which contain an unsaturated functionality to produce the compounds as shown in the following chemical structure of Formula VIII:
wherein R is defined above and R1 is a moiety containing an unsaturated functionality such as a moiety having the following formula:
where Rxe2x80x3 is a hydrogen or an alkyl group from C1-C20 and Rxe2x80x2xe2x80x3 may be a hydrogen, an alkyl group from C1-C20, or a carboxylic acid group or ester derivatives thereof. For example Rxe2x80x2 may be a methacrylate, acrylate, maleate, fumarate and the like.
In its broadest scope, the present invention is directed to a new phosphorus element-containing crosslinking agent advantageously used in epoxy-based formulations for preparing a flame retardant epoxy resin composition substantially free of halogen. The cross linkers of the present invention are preferably used as curing agents for epoxy formulations used in FR-4 laminates for printed circuit boards. Generally, the flame retardant composition includes (I) a non-halogenated epoxy resin material and (II) a phosphorus element-containing crosslinking agent.
A resin which is xe2x80x9csubstantially free of halogenxe2x80x9d means that the resin is completely free of halogen, i.e. 0% halogen, or that the resin contains some minor amount of halogen that does not affect the properties or performance of the resin, and is not detrimental to the resin. Usually resins which have not been halogenated with a halogen-containing compound are xe2x80x9csubstantially free of halogenxe2x80x9d.
xe2x80x9cSubstantially free of halogenxe2x80x9d, therefore, herein generally means that the resin contains less than 10 weight percent, preferably less than about 5 weight percent, more preferably less than about 1 weight percent, even more preferably less than 0.5 weight percent and most preferably zero weight percent of a halogen in the resin composition.
In order to obtain satisfactory ignition resistance, i.e. flame retardancy, and still obtain the benefit of resistance to water absorption, it is important that the amount of the phosphorus element in the epoxy resin composition is from about 0.2 wt % to about 5 wt %, preferably from about 0.5 wt % to about 3.5 wt %, even more preferably from about 1 wt % to about 3 wt %, and most preferably from about 1.5 wt % to about 2.8 wt %, based on the total of the solid resin composition.
The phosphorus element-containing crosslinking agent (II) of the present invention is preferably one or more compounds, or an isomeric mixture of two or more isomer compounds, having the following general chemical structural Formula I:
wherein R is independently a hydrogen or a C1-C10 alkyl group including for example, methyl, ethyl, propyl, butyl, etc.
Specific examples of the crosslinkers (II) of the present invention may include those having the following chemical structural Formulas II-IV:
The compounds of Formulas III and IV above are specific compounds wherein a CH3 group is in the 5 position of the phenyl ring as shown in Formula III or wherein a hydrogen is in the 3, 4, 5, and 6 positions of the phenyl ring as shown in Formula IV; and such compounds are described in Synthetic Communications, 1987, 17(4), 465-468. Heretofore, the compounds of Formulas III and IV have not been used as crosslinkers for epoxy resins, particularly for making flame retardant compositions.
The crosslinkers of the above Formula II are preferably used in the present invention. Formula II represents an isomeric mixture of two or more different triaryl phosphine oxide isomer compounds wherein the R group is a methyl and the methyl can be in the 3, 4, 5 or 6 position in each of the phenyl rings. The isomeric mixture of Formula II is new. A more preferred embodiment of the isomeric mixture of Formula II used in the present invention is when the mixture contains at least one of the isomers having at least one 2-hydroxy-4-methyl phenyl moiety and/or at least one of the isomers having at least one 2-hydroxy-5-methylphenyl moiety.
The ratio of 2-hydroxy-4-methylphenyl moiety to the 2-hydroxy-5-methyl phenyl moiety is generally dependent on the moiety ratios of the starting precursor; and the ratio can range from 99:1 to 1:99 and preferably, the ratio is from about 70:30 to about 30:70.
The cross-linker (II) of the present invention is preferably used in the epoxy resin composition in an amount of from about 50% to about 150% of the stoichionietric amount needed to cure the epoxy resin and more preferably from about 75% to about 125% of the stoichiometric amount needed to cure the epoxy resin, even more preferably from about 85% to about 110% of the stoichiometric amount needed to cure the epoxy resin.
Formulations that use the crosslinking agent of Formula II yield laminates with excellent glass transition temperatures (Tg) of from about 50xc2x0 C. to about 180xc2x0 C. and an ignition resistance of V-0/N-1.
Formulations made using the crosslinker of Formula II yield laminates have a Tg of preferably greater than 120xc2x0 C., more preferably greater than 135xc2x0 C., and most preferably greater than 150xc2x0 C. The crosslinker of Formula II also provides good resistance to water uptake for a phosphorus-containing additive/comonomer, with a moisture pickup of preferably less than about 1%, more preferably less than about 0.5%, and most preferably less than about 0.3% after about 40 minutes exposure time in a steam autoclave (known in the industry as the xe2x80x9cpressure cooker testxe2x80x9d). Thus, compounds of the general chemical structural Formula I, specifically the compound of Formula II, are superior to other known phosphorus-containing compounds used to prepare non-halogenated FR-4 laminates for printed circuit boards.
The compounds of Formulas I-IV may be prepared by a method described in Synthetic Communications, 1987, 17(4), pp. 465-468, incorporated herein by reference. Generally, the method of preparation of the compounds of the present invention involves the reaction of a corresponding precursor such as a triarylphosphate, with lithium diisopropyl amide in tetraydrofuran (THF) solvent at xe2x88x9278xc2x0 C. For example, commercially available triarylphosphate precursors such as tris(p,m-cresyl)phosphate and triphenylphosphate can be used as starting materials to prepare, on an industrial scale, the compounds of Formula II and Formula IV, respectively.
The crosslinker of Formula II is preferably soluble in aprotic and/or protic solvents commonly used for making epoxy resin formulations, particularly for use in laminate applications. The solvents include for example acetone, methylethyl ketone, methanol, ethanol, Dowanol PM*, N-methylpyrrolidone, dimethylforamide and the like. The solubility of the crosslinker is preferably greater than 30% solids content, more preferably greater than 40% solids contents and most preferably greater than 50% solids contents. The compounds of Formulas III and IV are high melting crystalline solids which are useful as crosslinking agents in other applications such as coatings, adhesives and composites.
An additional embodiment of the present invention is a compound which includes the glycidyl ether derivatives of Formula I, shown as the following chemical structural Formula V:
wherein R is as defined above.
The compounds of Formula V can be produced by epoxidizing the compounds of Formula I using well known techniques in the art such as reacting the compounds of Formula I with an epihalohydrin such as epichlorohydrin to prepare the epoxy resin.
The resulting epoxy resin of Formula V can be advantageously used per se as an epoxy resin base material, such as those described herein as the non-halogenated epoxy resin materials of component (I), for making a flame retardant composition which is curable with any curing agent. More particularly, the curing agent used can also be the phosphorus element-containing crosslinking agent (II) disclosed herein as Formula I. In another embodiment, the compound of Formula V may also be used in combination with other phosphorus element-containing compounds. The combination of the compounds of Formula V and Formula I produce curable compositions which can be used in applications such as flame retardant coatings, laminates, composites and adhesives.
More beneficially, the compounds of Formula V can be used in laminate applications to produce laminates which have a reduced water up-take because of the Pxe2x80x94C bonds as opposed to those compounds having a Pxe2x80x94Oxe2x80x94C bonds.
In still another embodiment of the present invention, the previously described epoxy resin compound of Formula V can be further reacted with a carboxylic acid material which contains an unsaturated functionality to make a vinyl ester resin as shown in the following chemical structure of Formula VIII:
wherein R is defined above and R1 is a moiety containing an unsaturated functionality such as a moiety having the following formula:
where Rxe2x80x3 is a hydrogen or an alkyl group from C1-C20 and Rxe2x80x2xe2x80x3 may be a hydrogen, an alkyl group from C1-C20, or a carboxylic acid group or ester derivatives thereof. For example R may be a methacrylate, acrylate, maleate, fumarate and the like.
Preferably, the epoxy vinyl ester resins of Formula VIII is produced by reacting a carboxylic acid material having an unsaturated functionality such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, and the like.
The amount of carboxylic acid material used is sufficient to completely react the acid functionality with all of the epoxy groups, i.e., stoichiometric amounts using techniques well known in the art. The epoxy vinyl ester resins may also be used with commonly reactive diluents such as styrene, divinyl benzene, and p-methyl styrene and other reactive diluents known in the art. The diluents are used for ease of fabricating, for example, composites; and for improving the properties of the final composites produced.
The compounds of Formula VIII are advantageously used to produce compositions which can be used in applications such as flame retardant coatings, laminates, composites and adhesives.
The crosslinking agent (also referred to as a xe2x80x9chardenerxe2x80x9d or xe2x80x9ccuring agentxe2x80x9d herein) of the present invention may be used alone, or in combination with one or more second different crosslinking agents, i.e., a co-crosslinking agent (VII). For example, the co-crosslinking agent used in the present invention may be selected from a multifunctional phenolic crosslinker, a nitrogen-containig crosslinker, styrenic maleic anhydride (SMA) or other phosphorus element-containing compounds.
In one optional embodiment, the composition of the present invention may include, as an additional crosslinking agent or co-crosslinker (VII), a multi-functional phenolic cross-linker which contains at least two or more functionalities. Examples of such phenolic crosslinking agents are described in co-pending U.S. Patent Application entitled, xe2x80x9cFlame Retardant Phosphorus Element-Containing Epoxy Resin Compositionsxe2x80x9d U.S. Pat. No. 6,645,631, filed of even date herewith, and incorporated by reference. For example, the multi-functional phenolic cross-links are preferably novolacs or cresol novolacs obtained by the condensation of phenols, cresols, xylenols or other alkyl phenols with formaldehyde. In the present invention, the resoles may also be used as the multi-functional phenolic cross-linker.
Preferably, if a multi-functional phenolic cross-linker is used in the present invention, the cross-linker has the following chemical structural Formula VI:
wherein xe2x80x9cRxe2x80x9d is hydrogen or a C1-C3 alkyl, e.g., methyl and xe2x80x9cnxe2x80x9d or an integer from 1 to 10. xe2x80x9cnxe2x80x9d preferably has an average value of from 0 to 5.
In another embodiment, the composition of the present invention may include as an additional crosslinking agent, a nitrogen-containing cross-linker (VII), used as a subsidiary cross-linker in addition to the phosphorus element-containing cross-linker (II), and with or without the multi-functional phenolic cross-linker. The nitrogen-containing co-crosslinking agent preferably has an amine functionality of at least 2. Suitable multi-functional cross-linkers are described in numerous references such as Vol. 6 Encyclopedia of Poly. Sci. and Eng., xe2x80x9cEpoxy resinsxe2x80x9d at 348-56 (J. Wiley and Sons 1986). Examples of suitable nitrogen-containing co-crosslinkers useful in the present invention may be found in WO 99/00451, incorporated herein by reference; and include for example, include polyamines, polyamides, sulpfhanilamide, diaminodiphenylsulfone and diaminodiphenyl methane and dicyandiamide, substituted dicyandiamide, 2,4-diamino-6-phenyl-1,3,5-triazin. When a nitrogen-containing crosslinker is used in the present formulation, the preferred nitrogen-containing co-crosslinkers are dicyandiamide, sulfanilamide and, 2,4-diamino-6-phenyl-1,3,5-triazine, more preferable sulfanilamide issued.
Another preferred embodiment of co-crosslinkers (VII) useful in the present invention are described in U.S. Pat. No. 6,613,839, entitled Latent Catalysts for Epoxy Curing Systems, issued Sep. 2, 2003, to Gan et al; incorporated herein by reference; and which include, for example, copolymers of styrene and maleic anhydride having a molecular weight (Mw), in the range of from 1500 to 50,000 and an anhydride content of more than 15 percent. Commercial examples of these materials include SMA 1000, SMA 2000, and SMA 3000 having styrene-maleic anhydride ratios of 1:1, 2:1, and 3:1, respectively, and having molecular weights ranging from 6,000 to 15,000; and which are available from Elf Atochem S.A.
When one or more co-crosslinkers are used in the present invention, the co-crosslinkers are present in an amount to cross-link less than 40% of stoichiometric amount needed to cure the epoxy resin. Preferably, the amount of the co-crosslinking agent in the epoxy resin is from 0 to 40% of the stoichiometric quantity needed to cure the epoxy content of the epoxy resin in the formulation.
The non-halogenated epoxy resin material (I) of the present invention may be selected from: (A) a non-halogenated epoxy resin; (B) a non-halogenated, phosphorus element-containing epoxy resin; (C) a mixture of:(1) a non-halogenated, non-phosphorus element-containing epoxy resin, and (2) a phosphorus element-containing compound; (D) the reaction product of: (1) a non-halogenated epoxy resin; and (2) a phosphorus element-containing compound; or (E) a combination of two or more of components (A) to (D).
Generally, the non-halogenated epoxy resin material (I) used in the present invention is a material which possesses on average more than 1 and preferably at least 1.8, more preferably at least 2 epoxy groups per molecule. In the broadest aspect of the present invention, the epoxy resin material may be any saturated or unsaturated aliphatic, cycloaliphatic, aromatic or heterocyclic compound which possesses more than one 1,2-epoxy group.
The non-halogenated epoxy resins (A) useful in the present invention include polyepoxides. The polyepoxide compound useful in the present invention is suitably a compound which possesses an average of from 1.9 to 2.1 1,2-epoxy groups per molecule. In general, the polyepoxide compound is saturated or unsaturated aliphatic, cycloaliphatic, aromatic or heterocyclic compound which possesses more than one 1,2-epoxy group. The polyepoxide compound can be substituted with one or more substituents which are non reactive with the isocyanate groups such as lower alkyls and halogens. Such polyepoxide compounds are well known in the art.
Illustrative polyepoxide compounds useful in the practice of the present invention are described in the Handbook of Epoxy Resins by H. E. Lee and K. Neville published in 1967 by. McGraw Hill, New York and U.S. Pat. No. 4,066,628. Examples of suitable aromatic polyepoxides are bisphenol-A, bisphenol-F, bisphenol-AD, bisphenol-S, tetramethyl bisphenol-A, tetramethyl bisphenol-F, tetramethyl bisphenol-AD, tetramethyl bisphenol-S, tetrabromobisphenol-A, tetrachlorobisphenol-A, biphenols such as 4,4-biphenol or 3,3xe2x80x2,5,5xe2x80x2-tetramethyl-4,4xe2x80x2-biphenol, and dihydroxynaphthalene. Examples of suitable aliphatic polyepoxides are diglycidyl esters of hexahydrophthalic acid and diglycidyl esters of dicarboxylic acids, epoxidized polybutadien epoxidized soyabean oil, and epoxidized diols. Cycloaliphatic epoxides include, for example, 3,4-epoxy-6-methylcyclohexyl carboxylate and 3,4-epoxycyclohexyl carboxylate. Examples of heterocyclic epoxy compounds are diglycidylhydantoin or triglycidyl isocyanurate (TGIC).
Preferred polyepoxides are glycidyl compounds of bisphenol-A, of bisphenol-F, of tetrabromobisphenol-A and of 3,3xe2x80x2,5,5xe2x80x2-tetramethyl-4,4-biphenol. Mixtures of any two or more polyepoxides can also be used in the practice of the present invention
Examples of a non-halogenated, phosphorus element-containing epoxy resin (B) useful in the composition of the present invention include:
1. Bisglycidylphenylphosphate as illustrated by the following chemical formula:
2. The epoxy phosphine oxides described in S. V. Levchik, G. F. Levchik, A. V. Antonov, M.Yu. Yablokova, O. I. Tuzhikov, O. O. Tuzhikov and L. Costa, 1999 including for example the following compounds:
wherein R is as previously defined; and
3. Aryl phosphinate epoxy ether 10-(2xe2x80x2,5xe2x80x2-bis(glycidyloxy)phenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DHQEP) as illustrated by the following chemical formula:
The synthesis of DHQEP as an effective flame retardant and thermal stabilizer for epoxy resins is described in Cho, Ching-sheng/Chen, Leo-wang/Chiu, Yie-shun; Polymer Bulletin 41, 45-52 (1998),
In another preferred embodiment the epoxy resin material (I) used in the present invention may (C) a mixture of (1) an epoxy compound containing at least two epoxy groups, and (2) a phosphorus-containing compound. It is possible to add the phosphorus containing compound (C) and the epoxy resin compound (C) to the overall composition of the present invention in order to form the epoxy resin material (I) in-situ.
In another preferred embodiment, the epoxy resin material (I) which is added to the overall composition of the present invention, may be (D) the reaction product of (1) an epoxy resin and (2) a phosphorus-containing D1 compound capable of reacting with the epoxy resin.
The aforementioned epoxy resin (C1) or (D1) is preferably one which has no lower alkyl aliphatic substituents, for example the glycidyl ether of a phenol novolac, or the glycidyl ether of bisphenol-F.
The most preferred epoxy resins (C1) or (D1) are epoxy novolac resins (sometimes referred to as epoxidised novolac resins, a term which is intended to embrace both epoxy phenol novolac resins and epoxy cresol novolac resins). Such epoxy compounds have the following general chemical structural Formula VII:
wherein xe2x80x9cRxe2x80x9d a is hydrogen or a C1-C3 alkyl, e.g., methyl and xe2x80x9cnxe2x80x9d is 0 or an integer from 1 to 10. xe2x80x9cnxe2x80x9d preferably has an average value of from 0 to 5.
Epoxy novolac resins (including epoxy cresol novolac resins) are readily commercially available, for example under the trade names D.E.N.(trademark) (Trademark of The Dow Chemical Company), Quatrex(trademark), Tactix(trademark). The materials of commerce generally comprise mixtures of various species of the above formula and a convenient way of characterizing such mixtures is by reference to the average, nxe2x80x2, of the values of n for the various species. Preferred epoxy novolac resins for use in accordance with the present invention are those in which nxe2x80x2 has a value of from about 2.05 to about 10, more preferably from about 2.5 to about 5.
The phosphorus-containing compound or monomer (C2) or (D2) contains some reactive groups such as a phenolic group, an acid group, an amino group, an acid anhydride group, or a phosphinate group (Pxe2x80x94H) which can react with the epoxy groups of the epoxy resin compound (C1) or (D1).
In a most preferred embodiment of the present invention the phosphorus-containing monomer (C2) or (D2) used in the present invention is for example, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide such as xe2x80x9cSanko-HCAxe2x80x9d commercially available from SANKO of Japan or xe2x80x9cStruktol Polydis PD 3710xe2x80x9d commercially available from Schill-Seilacher of Germany; 10-(2xe2x80x2,5xe2x80x2-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (HCA-HQ); bis(4-hydroxyphenyl)phosphine oxide; tris(2-hydroxyphenyl)phosphine oxide; dimethyl-1-bis(4-hydroxyphenyl)-1-phenylmethylphonate; an isomeric mixture of tris(2-hydroxymethylphenyl)phosphine oxides; or tris(2-hydroxy-5-methylphenyl) phosphine oxide; and mixtures thereof.
The phosphorus-containing compound (C2) or (D2) of the present invention may contain on average one or more than one functionality capable of reacting with the epoxy groups. Such phosphorus-containing compound preferably contains on average 0.9 to 3 functional groups capable of reacting with epoxy resin.
The compositions of the present invention preferably contain a catalyst (III) capable of promoting the reaction of the cross-linker of the present invention, and/or the phosphorus-containing compounds with the epoxy resin and promoting the curing of the epoxy resin.
Examples of suitable catalyst materials useful in the present invention include for example compounds containing or amine, phosphine, ammonium, phosphonium, arsonium or sulfonium moieties. Particularly preferred catalysts are heterocyclic nitrogen-containing compounds.
The catalysts (III) (as distinguished from cross-linkers) preferably contain on average no more than about 1 active hydrogen moiety per molecule. Active hydrogen moieties include hydrogen atoms bonded to an amine group, a phenolic hydroxyl group, or a carboxylic acid group. For instance, the amine and phosphine moieties in catalysts are preferably tertiary amine or phosphine moieties; and the ammonium and phosphonium moieties are preferably quaternary ammonium and phosphonium moieties. Among preferred tertiary amines that may be used as catalysts are those mono- or polyamines having an open-chain or cyclic structure which have all of the amine hydrogen replaced by suitable substituents, such as hydrocarbyl radicals, and preferably aliphatic, cycloaliphatic or aromatic radicals. Examples of these amines include, among others, 1,8-diazabicyclo (5.4.0)undec-7-en (DBU), methyl diethanol amine, triethylamine, tributylamine, dimethyl benzylamine, triphenylamine, tricyclohexyl amine, pyridine and quinoline. Preferred amines are the trialkyl, tricycloalkyl and triaryl amines, such as triethylamine, triphenylamine, tri-2,3-dimethylcyclohexyl)amine, and the alkyl dialkanol amines, such as methyl diethanol amines and the trialkanolamines such as triethanolamine. Weak tertiary amines, for example, amines that in aqueous solutions give a pH less than 10 in aqueous solutions of 1 M concentration, are particularly preferred. Especially preferred tertiary amine catalysts are benzyldimethylamine and tris-dimethylaminomethyl) phenol.
Examples of suitable heterocyclic nitrogen-containing catalysts (III) include those described in U.S. Pat. No. 4,925,901. Preferable heterocyclic secondary and tertiary amines or nitrogen-containing catalysts which can be employed herein include, for example, imidazoles, benzimidazoles, imidazolidines, imidazolines, oxazoles, pyrroles, thiazoles, pyridines, pyrazines, morphoimes pyridazines, pyrimidines, pyrrolidines, pyrazoles, quinoxalines, quinazolines, phthalozines, quinolines, purines, indazoles, indoles, indolazines, phenazines, phenarsazines, phenothiazines, pyrrolines, indolines, piperidines, piperazines and combinations thereof. Especially preferred are the alkyl-substituted imidazoles; 2,5-chloro-4-ethyl imidazole; and phenyl-substituted irnidazoles, and mixtures thereof. Even more preferred are N-methylimidazole; 2-methylimidazole; 2-ethyl4-methylimidazole; 1,2-dimethylimidazole; and 2-methylimidazole. Especially preferred is 2-phenylimidazole.
Preferably a Lewis acid (IV) is also employed in the composition of the present invention, especially when the catalyst (III) is, particularly a heterocyclic nitrogen-containing compound.
Examples of heterocyclic nitrogen-containing catalysts(III) which are preferably used in combination with Lewis acids (IV) are those described in EP-A-526488, EP A 0458502 and GB A 9421405.3. Examples of suitable Lewis acids useful in the present invention include halides, oxides, hydroxides and alkoxides of zinc, tin, titanium, cobalt, manganese, iron, silicon, aluminium, and boron, for example Lewis acids of boron, and anhydrides of Lewis acids of boron, for example boric acid, metaboric acid, optionally substituted boroxines (such as trimethoxyboroxine), optionally substituted oxides of boron, alkyl borates, boron halides, zinc halides (such as zinc chloride) and other Lewis acids that tend to have a relatively weak conjugate base. Preferably the Lewis acid is a Lewis acid of boron, or an anhydride of a Lewis acid of boron, for example boric acid, metaboric acid, an optionally substituted boroxine (such as trimethoxy boroxine, trimethyl boroxine or triethyl boroxine), an optionally substituted oxide of boron, or an alkyl borate. The most preferred Lewis acid is boric acid. These Lewis acids are very effective in curing epoxy resins when combined with the heterocyclic nitrogen-containing compounds, referred to above.
The Lewis acids and amines can be combined before mixing into the formulation or by mixing with the catalyst in-situ, to make a curing catalyst combination. The amount of the Lewis acid employed is preferably at least 0.1 moles of Lewis acid per mole of heterocyclic nitrogen compound, more preferably at least 0.3 moles of Lewis acid per mole of heterocyclic nitrogen-containing compound.
The formulation preferably contains no more than 3 moles of Lewis acid per mole of catalyst and more preferably contains no more that 2 moles of Lewis acid per mole of catalyst The total amount of the catalyst is from about 0.1 wt % to about 3 wt %, based on the total weight of the Composition, preferably from about 0.1 wt % to about 2%.
The compositions of the present invention may also optionally contain one or more additional flame retardant additives (V), including for example, red phosphorous or liquid or solid phosphorus-containing compounds, for example, ammonium polyphosphate, a phosphite, or phosphazenes, nitrogen-containing fire retardants and/or synergists, for example melamines, urea, cynamide, guanidine, cyanuric acid, isocyanuric acid and derivatives of those nitrogen-containing compounds, halogenated flame retardants, halogenated epoxy resins (especially brominated epoxy resins) synergistic phosphorus-halogen containing chemicals or compounds containing salts of organic acids, inorganic metal hydrates, boron or antimony. Examples of suitable additional flame retardant additives are given in a paper presented at xe2x80x9cFlame retardantsxe2x80x94101 Basic Dynamicsxe2x80x94Past efforts create future opportunitiesxe2x80x9d, Fire Retardants Chemicals Association, Baltimore Marriot inner harbour hotel, Baltimore Md., Mar. 24-27 1996.
When additional fire retardants which contain a phosphorus element are present in the composition of the present invention, the phosphorus element-containing fire retardants are generally present in amounts such that the total phosphorous content of the epoxy resin composition is from about 0.2 wt % to about 5 wt %.
Other non-epoxy, phosphorus additives which can be used in the present invention may include for example phosphorus-guanamine having the following chemical structure:
where X is CR3R4-(CR1R2)nxe2x80x94CR5R6 or o-phenylidene, n is 0 or 1 R1-R8 may be the same or different and represent H, CH3, C2H5.
The phosphorus-quanamine above is found to be a highly suitable alternative to brominated epoxy resins for printed circuit board (PCB) applications as described in Buser, Antonius Johannes Wilhelmus/Schutyser, Jan Andre Jozef, Akzo Nobel N.V. European Pat. 0825217 A1 (25.02.1998) and Buser, Antonius Johannes Wilhelmus/Schutyser, Jan Andre Jozef, Akzo Nobel N.V. European Pat. WO 98/07731 (26.02.98).
Another phosphorus additive useful in the present invention is xe2x80x9cAntiblaze #1045xe2x80x9d available from Albright and Wilson. Antiblaze #1045 is a cyclic phosphonate dimer containing 20.8% phosphorous and has the following structure:
The following amino triazine phosphates are also phosphorus additives which may be used in the present invention:
where R1, R2 and R3 is independently H or a C1-C40 alkyl group such as methyl.
The composition of the present invention may also include other inorganic fillers (VI), for example fillers such as aluminum trihydroxide e.g. xe2x80x9cMartinal OL-104xe2x80x9d from Martinswerke GmbH; magnesium hydroxide, e.g. xe2x80x9cZerogen 30xe2x80x9d available from Martinswerke GmbH; and ammonium polyphosphate, e.g. xe2x80x9cExolit 700xe2x80x9d available from Clariant GmbH. The aforementioned inorganic fillers can be added to the composition of the present invention to improve the flame retardant properties of the composition.
Solvents (VIII) may also optionally be used in the composition of the present invention. When a solvent is used it may include for example, propylene glycolmethylether (Dowanol PM(trademark)), methoxypropylacetate (Dowanol PMA(trademark)), methylethylketone (MEK), acetone, methanol, and combinations thereof When a solvent is used in the present invention, the amount of solvent present in the epoxy resin composition of the present invention is generally form 0 wt % to about 50 wt %; preferably from about 10 wt % to about 40wt % and more preferably from about 10 wt % to about 35 wt %, depending on the end use application of the epoxy resin composition.
Optionally, in some applications it may be desirable to add a small amount of a halogenated epoxy resin (IX, provided the halogenated epoxy resin is added in an amount such that the halogen content of the overall epoxy resin composition of the present invention is less than 10 weight percent.
The compositions of the present invention can be produced by mixing all the components together in any order. Preferably, the compositions of the present invention can be produced by preparing a first composition comprising the epoxy resin, and the second composition comprising the crosslinking agent. Either the first or the second composition may also comprise a phosphorus-containing compound a curing catalysts a multi-functional phenolic co-crosslinking agent and/or a nitrogen-containing co-crosslinking agents. All other components may be present in the same composition, or some may be present in the first, and some in the second. The first composition is then mixed with the second composition, and cured to produce a fire retardant epoxy resin.
The compositions of the present invention can be used to make composite materials by techniques well known in the industry much as by pultrusion, moulding, encapsulation, or coating.
The present invention is particularly useful for making B-staged prepregs and laminates by well known techniques in the industry.
A number of preferred embodiments of the present invention are illustrated, in the following specific Examples.

Phosphorus element-containing crosslinking agents and flame retardant phosphorus element-containing epoxy resin compositions prepared therewith


A surgical instrument (10), comprising: a surgical execution component (100), a linkage part (200), and a manipulation component (300), the distal end of the linkage part (200) being connected to the surgical execution component (100) and the proximal end of the linkage part (200) being connected to the manipulation component (300). The surgical instrument (10) uses the linkage part (200) having two rotational degrees of freedom, such that when the manipulation component (300) drives, by means of the linkage part (200), the surgical execution component (100) to rotate at a fifth rotational degree of freedom (R5) and/or a sixth rotational degree of freedom (R6), the swing directions of the surgical execution component (100) and the manipulation component (300) at a first rotational degree of freedom (R1) and a second rotational degree of freedom (R2) are consistent. Therefore, the surgical instruction (10) implements technical effects of improving the moving direction accuracy of the surgical execution component (100), improving the accuracy of the action of the surgical instruction (10), and facilitating surgical operations.

In minimally invasive surgery, especially laparoscopic or endoscopic surgery, a tiny cut is made, which usually requires the use of minimally invasive surgical instruments for achieving a better treatment result with reduced damages to other tissues. During the operation, unnecessary movements of an existing minimally invasive surgical instrument are easily transmitted to an end effector of the surgical instrument, thus affecting the surgical instrument's movements.
Chinese Patent Application No. CN107072684A proposes an attachment apparatus for a remote access tool, which includes a cuff configured to attach to the user's forearm and a coupling joint configured to connect the cuff to a frame so that the cuff has 1 to 4 moving degrees of freedom relative to the frame.
Chinese Patent Application No. CN105592801A proposes a control unit for a medical device, which includes: a palm interface engageable by a palm of a hand; a restraint capable of elastically deforming to apply a restraining force to the back of the hand; and a finger interface engageable by one or more fingers of said hand.
Chinese Patent Applications No. CN107080588A and No. CN107260307A propose a cable-driven control device of the minimally invasive surgery robot and a cable-driven clamping device of the minimally invasive surgery robot.

SHANGHAI MICROPORT MEDBOT (GROUP) CO., LTD.


A pair of rigid metallic clips is inserted over containment numbers in a fiberoptic connector coupling. Rigid leg members mounted on the clips extend along latching members of the containment members, thereby limiting displacement of the latching members owing to spring pressure in connector sleeves joined by the connector coupling.

The field of the invention is couplers for fiber optic connector sleeves.
The prior art has provided connector couplings for joining fiber optic connector sleeves useful for widely used connectors, such as SC connectors. Spring forces internal to the fiber optic connector sleeves urge two opposing optical fiber holding ferrules to be connected against each other. Under the basic principle of action-reaction, however, an opposing spring force is created which is taken up by latches mounted on containment members into which the ferrules are inserted. Applicant has found that, over time, the constant reactive spring force causes strain on the external plastic housing that is welded or glued around the latch fingers. Such strain can cause failure of the entire connector coupling assembly. Therefore, it is believed that a need exists to improve the prior art connector couplings to decrease or eliminate the risk of such connector coupling failures.

Metal internal holding clips for fiber optic connector coupling


A programmable logic controller (PLC) assembly includes a bottom housing with a base, a first plurality of elongate alignment features extending from the bottom housing transverse to the base, and a first connection feature. The PLC assembly includes a central processing unit with a circuit board and at least two receptacles therethrough configured to engage and slide along at least two of the first plurality of alignment features. The at least two of the first plurality of alignment features are positioned asymmetrically with respect to the base. The PLC assembly includes an upper housing with a second connection feature configured to slidably couple with the first connection feature and a second plurality of elongate alignment features configured to slidably engage at least two of the first plurality of alignment features, which are positioned asymmetrically with respect to the base.

The invention relates generally to industrial automation and control systems, such as those used in industrial and commercial settings. More particularly, embodiments of the present invention relate to techniques for providing a programmable controller assembly with features that facilitate alignment of components of the programmable controller during assembly.
Industrial automation and control systems are known and are in use for controlling factory automation and the like. Such systems typically include various components that cooperate to monitor and control a process and/or system (e.g., a manufacturing process or a machine). A programmable controller is typically a central feature of a control system. For example, a typical control system includes one or more programmable logic controllers that coordinate with sensors, semiconductor power electronic circuits, power supplies, motor starters, relays, and so forth to control features and actions throughout an associated system or process. In operation, a typical programmable logic controller examines a series of inputs reflecting the status of a controlled process and changes outputs affecting control of the controlled process. For example, a programmable logic controller may receive an analog signal from a sensor and adjust an output to an actuator based on a value of the signal and associated logic programmed in a memory of the controller.
A typical programmable controller includes several major components that are separately manufactured and then assembled together. For example, a typical programmable controller includes housing components and at least one circuit board. These components are typically manually aligned during assembly so that screws can be passed through openings in one or more of the components to hold the assembly together.

Programmable controller component with assembly alignment features


An embroidery data generating device is disclosed. The embroidery data generating device generates embroidery data that is used for sewing an embroidery pattern including multiple color-wise pattern sections with a sewing machine and that includes thread color data specifying a color of each of the color-wise pattern sections. The embroidery data generating device includes a first storage device that stores multiple entries of preset color information; an extractor that randomly extracts color data used as the thread color data from each entry of the color information stored in the first storage device; and an allocator that randomly allocates the color data extracted by the extractor to each of the thread color data associated with each of the color-wise pattern sections.

Sewing machines have been available that sew embroidery patterns based on embroidery data. Such sewing machines store data of embroidery patterns in its internal storage or external storage such as ROM cards and flexible disks. The user is allowed to choose the desired pattern from the selection of such embroidery patterns. The sewing machine reads the embroidery data of the selected embroidery pattern and forms embroidery patterns on the workpiece by transferring the embroidery frame holding the workpiece by way of the transfer mechanism.
The embroidery data of embroidery patterns configured by multiple patterns contains thread color data which is associated with a color-wise pattern section and thus, the color-wise pattern section is sewn in the color of the preset thread color. When a color of a given color-wise pattern section is similar to the color of the workpiece, it may be difficult to distinguish the color-wise pattern section from the workpiece. Taking the example of an embroidery pattern of a "flower" in which the color-wise pattern corresponding to the petals of the flower are identical or similar in color as the workpiece, it may be difficult to distinguish the petals from the workpiece. Thus, the finished pattern may unwantedly appear as a strange embroidery pattern without any pedals.
To address such concerns, embroidery data generating devices have been proposed which pre-store coloring data containing preferable combinations of color. The embroidery data generating device is configured to specify the color of the thread color data associated with the color-wise patterns section based on such coloring data and workpiece data containing information such as the color of the workpiece.
According to such embroidery data generating device, coloring data that defines preferable combinations of colors is pie-stored and the color of the color-wise pattern section of the embroidery pattern is primarily determined based on the workpiece color and the coloring data. However, the user may not want the color of the color-wise pattern section to be confined by the workpiece color or a predetermined color but rather sew the pattern by specifying a preferred color or in an unusual coloring. However, allowing such user specification requires every data entry of the color-wise patterns to be parsed to determine the availability of the specified color and thus, is cumbersome.

Embroidery data generating device, computer readable medium storing embroidery data processing program, and sewing machine


The present invention is directed to a method for expression of at least one heterologous gene in a host cell comprising transforming a host cell with at least one nucleic acid construct comprising a complete xcex1 subunit of an RNA polymerase or a portion thereof of a hybrid nucleic acid containing a portion of the xcex1 subunit of an RNA polymerase obtained from the same genus as the heterologous gene, and transforming the host cell, with at least one heterologous gene; and culturing the transformed host cell. The present invention further is directed to nucleic acid molecules used in the present method, vectors containing these nucleic acid molecules, and host cells containing the nucleic acid molecules. The nucleic acid encoding the xcex1 subunit of an Agrobacterium RNA polymerase and the corresponding amino acid sequence and portions thereof is disclosed.

The present invention relates to nucleic acid molecules and constructs containing these nucleic acid molecules and methods of using these constructs to express heterologous genes in hosts. In particular, the nucleic acid molecules of the present invention comprise a DNA sequence encoding at least a portion of the xcex1 subunit of the RNA polymerase (referred to herein as RNAP) obtained from the same genus source from which the heterologous genes were originally isolated. The nucleic acid constructs also can optionally comprise, if required for expression of the heterologous genes, at least one gene encoding a transcriptional regulator, also obtained from the same genus as the source of the heterologous genes.
Although many host cell systems are well characterized and utilized to express a number of heterologous genes, there are still many genes that cannot be expressed in such host cell systems, as for example, Escherichia coli (E. coli). It is believed that the lack of expression in these host cell systems is a result of the promoter sequences of the heterologous genes not being recognized by the host RNAP. The present invention has solved this problem by showing that this block in expression can be overcome by co-expression of at least a portion of the rpoA gene product, the gene that encodes the xcex1 subunit of the RNAP, obtained from the same genus as the source of the heterologous gene that is desired to be expressed in the new host cell. The co-expressed xcex1 subunit of the RNAP from the same genus as the source of the heterologous gene combines with the other subunits of the RNAP, xcex2, xcex2xe2x80x2, and "sgr", to form a functional RNAP. Additionally, if transciptional regulators, such as transcriptional activators or transcriptional repressors, or additional other subunits of the RNAP, such as xcex2, xcex2xe2x80x2 or "sgr", are required to obtain expression of the heterologous gene, then these additional components also are obtained from the same genus as the source of the heterologous gene. Since two different rpoA genes are present in a single host cell, there will be various combinations of RNAPs present in the host cell (1) RNAP containing two xcex1 subunits of the same genus as the host (2) RNAP containing two xcex1 subunits from the same genus source as the heterologous gene, and (3) RNAP containing one xcex1 subunit from the same genus as the host and one xcex1 subunit from the same genus source as the heterologous gene. A heterologous gene is intended to mean a gene that is not from the same source as the host cell.
Agrobacterium tumefaciens is a Gram-negative soil bacterium which is the causative agent of Crown Gall disease, affecting primarily dicotyledonous plant species (reviewed in 18, 62). The pathogen incites production of the characteristic tumor through the transfer of a piece of DNA (T-DNA) from the Ti (Tumor inducing) plasmid into susceptible plant cells, with subsequent integration into the host genome. The T-DNA contains genes that direct the biosynthesis of auxin and cytokinin in infected cells (1, 57), resulting in uncontrolled cell division leading to production of the characteristic tumor. The T-DNA also contains genes for the biosynthesis of unique compounds called opines which the bacterium can utilize as a carbon and nitrogen source (39).
Successful transfer of the T-DNA is dependent on the coordinated expression of virulence (vir) genes located on the Ti plasmid but separate from the T-DNA. Expression of vir genes occurs in response to certain phenolic compounds released from wounded plants (54). This expression is augmented by monosaccharides (5, 52), and an acidic pH (38) which are characteristics of plant wound sites. Expression of vir genes requires virA and virG, which are members of the family of two component regulatory systems (60). VirA is an inner membrane associated histidine protein kinase which autophosphorylates in response to the environmental signals (19, 28). The phosphate moiety is subsequently transferred to the aspartate residue of VirG, which in turn activates transcription from promoters containing a specific 12 base pair sequence called the vir box, present in the promoters of all vir genes (29, 44). In addition to virA and virG, other chromosomally encoded genes have been identified in A. tumefaciens that have been shown to modulate virulence gene expression either directly or indirectly (12, 15, 20, 61).
The use of E. coil as a heterologous host in which to study the regulation of A. tumefaciens virulence genes and the mechanism of T-DNA transfer constitutes an ideal model system given the degree of characterization at both the biochemical and genetic level. However, all previous attempts to reconstitute vir gene expression in E. coil have not been successful. Possible explanations for the lack of vir gene expression include the presence of unidentified regulatory genes in A. tumefaciens required for vir induction, and/or that E. coli may contain specific repressor(s) of vir gene induction.
A characteristic of vir gene promoters is the absence of a strong xe2x88x9235 sequence (10). Dnase I footprinting studies have shown that VirG protects a region extending into where the xe2x88x9235 consensus sequence should be (29, 44). It has been suggested that binding of VirG may functionally replace the xe2x88x9235 consensus sequence allowing transcription to occur. This situation is similar to Class II CAP-dependent promoters, in which the CAP binding site overlaps with the xe2x88x9235 sequence. Studies have demonstrated that transcription at Class II CAP-dependent promoters requires interaction between CAP and the xcex1 subunit (rpoA) of RNAP (42, 49, 64). Many transcriptional factors from E. coli are known to require interaction with the xcex1 subunit of RNAP, including FNR (59), GaiR (9), MarA (24), Mer R (7), MetR (23) OxyR (56), OmpR (21), Rob (26), SoxS (25), and TyrR (34). Analysis of the xcex1 subunit from E. coli indicates the presence of two independent domains, the N-terminal domain and the C-terminal domain (21, 27, 63). The N-terminal domain (NTD) is involved in the assembly of the core polymerase, while the C-terminal domain (CTD) is involved in interaction with certain transcriptional regulators (7, 9, 21, 23, 24, 25, 26, 32, 34, 47, 56, 59). Recently, interaction between the NTD and CAP at Class II CAP-dependent promoters has been demonstrated (42,49).
The present methods of expressing heterologous genes are particularly useful to express multiple genes or operons in a metabolic pathway by co-expressing the rpoA gene product obtained from the same natural hosts from which the genes or operons were originally isolated with the multiple genes. The present method provides an advantage over existing multiple gene expression systems by eliminating the need to separately isolate each gene in the metabolic pathyway and link each gene to a promoter that is functional in the host. Expression of heterologous genes for an entire metabolic pathway in hosts is particularly useful to produce particular metabolites, such as pharmaceuticals, food supplements, chemical products or fine chemical products.
The present invention further provides nucleic acid molecules and methods whereby heterologous genes encoding metabolites in an entire metabolic pathway can be introduced into hosts so that these hosts possess specific catabolic and/or metabolic characteristics that allow the hosts to grow or express gene products under specific environmental conditions. These hosts are useful in bioremediation, bioassays and biocontrol studies where manipulation of natural or symbiotic bacterial flora is desired, such as in the control of parasites or insects where bacterial symbiants are involved.
The present invention broadly relates to the expression of heterologous genes in a host using nucleic acid molecules comprising a gene encoding the complete xcex1 subunit of the RNAP obtained from the same genus as the source of the heterologous genes or at least a portion of the xcex1 subunit of the RNAP. The host and the heterologous genes to be expressed may be prokaryotic or eukaryotic in origin, however, prokaryotic hosts are preferred. The present invention also relates to a hybrid nucleic acid molecule encoding a hybrid xcex1 subunit of RNAP, where a first nucleic acid comprises at least a portion of the rpoA gene encoding the xcex1 subunit of an RNAP obtained from the same genus as the source of the host cell and a second nucleic acid comprises at least a portion of the xcex1 subunit of an RNAP obtained from the same genus as the heterologous gene.
The present invention specifically discloses the rpoA gene from Agrobacterium encoding the xcex1 subunit of the RNAP and the corresponding amino acid sequence. Portions of both the rpoA gene and the xcex1 subunit of RNAP of Agrobacterium also are encompassed by the present invention, particularly the sequences disclosed in FIGS. 2A (SEQ ID NO:1) and 2B (SEQ ID NO:2). The rpoA gene is useful in methods of expressing Agrobacterium genes in hosts, particularly prokaryotic host cells. Prior to the present invention, it was not possible to express Agrobacterium genes, particularly Agrobacterium virulence genes, in E. coli. Therefore, the present invention provides a method for studying Agrobacterium genes and their regulation.
The invention also relates to genes encoding hybrid rpoA genes that comprise at least a portion of an rpoA gene from the same genus as a heterologous gene which is expressed, such as the Agrobacterium rpoA gene, with the remainder of the rpoA gene obtained from the same genus as the host cell in which the heterologous gene is expressed.
The present invention is directed to an isolated nucleic acid molecule encoding the complete xcex1 subunit of an RNAP of Agrobacterium or at least a portion thereof. Specifically, the present invention is directed to an isolated nucleic acid molecule encoding the complete xcex1 subunit of an RNAP of Agrobacterium, in which the amino acid sequence of the xcex1 subunit is depicted in. FIG. 2A (SEQ ID NO:1) or at least a portion of this sequence. More specifically, the present invention is directed to an isolated nucleic acid molecule comprising the complete nucleic acid sequence as depicted in FIG. 2B (SEQ ID NO:2) or at least a portion thereof. These isolated nucleic acid molecules encoding at least a portion of the xcex1 subunit of an RNAP of Agrobacterium also are optionally linked to a promoter that is functional in the host in which these molecules are expressed. Further, the present invention is directed to vectors containing these nucleic acid sequences or molecules. The vectors are useful in transforming host cells for the expression of heterologous gene(s). The invention is also directed to host cells that are transformed with the nucleic acid molecules described herein. The nucleic acid molecules useful to transform the host cells are operably linked to a promoter and encode an xcex1 subunit of an RNAP or at least one heterologous protein.
The present invention is also directed to a hybrid nucleic acid molecule for the expression of at least one heterologous gene in a host cell comprising a first nucleic acid sequence encoding at least a portion of the xcex1 subunit of an RNAP obtained from the same genus as the host cell and a second nucleic acid sequence encoding at least a portion of the xcex1 subunit of an RNAP obtained from the same genus as the source of the heterologous gene; and vectors containing the hybrid nucleic acid molecule.
The present invention is further directed to a method of expressing at least one heterologous gene in a host cell comprising transforming a host cell with a vector comprising a nucleic acid molecule encoding a complete xcex1 subunit of RNAP from the same genus as the source of the heterologous gene or at least a portion thereof, and also transforming the host cell with a vector comprising at least one heterolgous gene. The nucleic acid molecule and the heterologous gene(s) also may be contained in one vector but preferably these sequences are contained within two or more vectors. In a further embodiment, the present invention is also directed to a method of expressing at least one heterologous gene in a host cell comprising transforming a host cell with a vector comprising a hybrid nucleic acid molecule comprising a first nucleic acid sequence encoding at least a portion of the xcex1 subunit of an RNAP obtained from the same genus as the host cell and a second nucleic acid sequence encoding at least a portion of the xcex1 subunit of an RNAP obtained from the same genus as the source of the heterologous gene, and transforming the host cell with a vector comprising at least one heterologous gene; and culturing the transformed host cell under conditions where the heterologous gene is expressed in the host cell. The host cell also may be transformed with a single vector containing the nucleic acid molecule encoding the complete xcex1 subunit of the RNAP, a portion thereof or a hybrid molecule comprising a portion of the xcex1 subunit of the RNAP, and with the heterolgous gene(s) or xcex1 subunit of the RNAP peferably, two or more vectors may be used. The nucleic acid molecules encoding the xcex1 subunit and the heterologous gene(s) may be in separate vectors for transformation of the host cell. The host cell can optionally be transformed with at least one gene encoding a heterologous transcriptional regulator obtained from the same genus as the source of the heterologous gene. The heterologous gene may comprise multiple genes or operons in the same metabolic pathway.

Board of Trustees of the University of Arkansas

Rutgers the State University of New Jersey


Disclosed herein is a battery pack including: a plurality of cylindrical battery cells; and an electrode tab for electrically connecting terminals of the battery cells arranged in a pattern; wherein the electrode tab is formed with a position matching hole for position matching to the terminal of the battery cell, at a fixation part for fixation to the terminal of the battery cell.

1. Field of the Invention
The present invention relates to a battery pack with which it is possible to enhance productivity of a welding work.
2. Description of the Related Art
A battery pack includes a plurality of cylindrical battery cells, electrode tabs for electrically connecting terminals of the battery cells arranged in a certain pattern, a lower case for containing the battery cells electrically connected through the electrode tabs, and an upper cover for covering the lower case containing the battery cells therein, and is detachably attached to a body of an electronic apparatus, to be used as a power source for the electronic apparatus (refer to Japanese Patent Laid-Open No. 2003-257388).
In the battery packs according to the related art, in the case of spot welding a nickel electrode tab to the battery cell, the non-effective shunt current which flows directly from a welding electrode on one side to a welding electrode on the other side through the electrode tab without flowing through the welding spot and which therefore does not contribute to the welding intended has been suppressed by providing a welding slit such as to elongate the non-effective shunt current path. Besides, the welding slit has functioned also as a register mark for position matching between the electrode tab and a battery cell terminal and for applying the welding electrodes at the time of spot welding.
In such a battery pack, however, in the case of spot welding a copper material electrode tab, the electrical resistivity of copper is very low so that the magnitude of the non-effective shunt current would not materially be changed even when the non-effective shunt current path is elongated by providing a welding slit. Besides, in the case of a copper material electrode tab, a comparison between the mean value of weld strength in the presence of a welding slit and that in the absence of the welding slit has revealed that a higher weld strength is obtained when the welding slit is absent.
However, in the battery pack in which the welding slit is absent, there is no register mark to be used for position matching between the electrode tab and the battery cell terminal and for applying the welding electrodes at the time of spot welding. Therefore, it is difficult to perform welding accurately at the desired position, and the productivity of the welding operation may be worsened.

Battery pack having enhanced manufacturing efficiency