A process for catalytic conversion of low value hydrocarbon streams to light olefins in comparatively higher yields is disclosed. Propylene is obtained in amounts higher than 20 wt. % and ethylene higher than 6 wt. %. The process is carried out in a preheated cracking reactor having a single riser and circulating an FCC catalyst. The riser is divided into three temperature zones in which different hydrocarbon feeds are introduced. An oxygenate feed is introduced in the operative top zone in the riser. Heat for the endothermic cracking is obtained by the exothermic reaction of converting the oxygenate feed into gas and/or from a regenerator in which the spent FCC catalyst is burnt.

Extensive efforts are being made to maximize the production of light olefin such as ethylene and propylene in order to meet the growing demand of light olefins. As used in this specification the term light olefin is deemed to mean ethylene, propylene but not butylene. Generally, propylene and ethylene are produced as by-products (4-6 wt. % propylene and 2-3 wt. % ethylene) while manufacturing fuels such as gasoline, diesel and the like by employing the Fluid catalytic cracking (FCC) process. Propylene is separated from FCC reactor product vapors for getting petrochemical feedstock. However, the separation of ethylene from other FCC products is not very economically attractive due to the lower quantity of the same; therefore, it is used as a refinery fuel gas. Since late nineties, some FCC units have been operating at higher severity to get propylene of 10-12 wt % of the fresh feed. To further increase the propylene yield, different processes have been developed around FCC configuration. Some of them are still operational.
Existing Knowledge
U.S. Pat. No. 4,980,053 discloses a process called Deep Catalytic Cracking (DCC) wherein a preheated hydrocarbon feedstock is cracked over heated catalyst in a reactor to produce light olefins. The obtained gaseous products are separated into ethylene, propylene, butylenes and other components.
As, this process requires 5-10 seconds of contact time, it produces relatively substantial quantity of undesirable products like dry gas.
U.S. Pat. No. 5,846,402 discloses a catalytic conversion of heavy hydrocarbon feedstock to produce high yield of liquefied petroleum gas and light olefins having 3 to 4 carbons. The cracking of feedstock is carried out in a high velocity riser reactor under catalytic cracking conditions that include high catalyst to oil ratio and high riser temperature. The cracking catalyst as disclosed in aforementioned US patent is a solid acid catalyst comprising ultra stable-Y (USY) zeolite, shape selective pentasil zeolite and active matrix. The U.S. Pat. No. 5,846,402 teaches the art of cracking heavy hydrocarbon in a single riser configuration at very high severity.
Further, U.S. Pat. No. 7,491,315 discloses a process of cracking the hydrocarbon in a dual riser configuration. The heavy hydrocarbon like vacuum gas oil cracks in a first riser at relative lower severity to produce products; the products obtained from the first riser i.e. light crack naphtha and C4 stream are then allowed to crack in a second riser at very high reaction severity. The cracking catalyst is a combination catalyst having a conventional FCC catalyst in combination with ZSM-5 catalyst. The process as disclosed in U.S. Pat. No. 7,491,315 is a heat balanced process in which the heat generated by burning the coke deposited on catalyst is utilized further. However, the additional coke precursors are introduced in the riser to obtain heat-balanced condition. The major drawback of two-riser configuration is that it requires an additional catalyst circulation loop including new riser reactor which adds to increased capital expenditure and space.
Mehlberg et. al. in their United States Patent Application 2010/0168488 disclose a process of cracking multiple feedstock in a dual riser reactor vessel. The reason for opting two reactor vessels is argued to be an artifact of equilibrium composition governing the C3-C5 range olefins. While two separate reactors, two separate main columns and gas connection are good to achieve close to equilibrium yield of light olefin and avoid recycling of lower crack-able C4-C6 hydrocarbons, such scheme add to duplication of many equipment/vessel thereby leading to high capital expenditure. There are some "On-purpose" propylene production processes which convert low value naphtha feedstock to light olefins by employing ZSM-5 zeolite based catalyst at very high reaction severity. The light feed stocks make very less catalytic coke on ZSM-5 zeolite based catalyst; therefore, these processes require external heat supply to satisfy heat demand for the endothermic cracking in the riser. In general, fuel oil in combination with heavy oil product, produced in the process, is injected in the regenerator as a source of heat. But, the continuous burning of fuel in regenerator accelerates hydrothermal deactivation of catalyst. Further, some part of feed material is being continuously burned for supplying additional heat which leads to some bearing on process economics. U.S. Pat. No. 7,601,663 discloses a cracking of straight run naphtha to light olefins in a riser at very high riser temperature using ZSM-5 zeolite based catalyst. The heat balance is satisfied by preheating the feedstock in a separate furnace and by burning the fuel oil in a regenerator which further leads to higher hydrothermal catalyst deactivation resulting requirement of higher catalyst make up rate.
U.S. Pat. No. 5,171,921 discloses a new process for converting C3 to C20 hydrocarbons to light olefins using ZSM-5 zeolite catalyst having phosphorous. In this process, the production of catalyst coke is very less, therefore, the heat required for endothermal cracking is supplied partially by preheating the feedstock and continuous burning the fuel oil in a regenerator.
Further, U.S. Pat. No. 7,867,378 discloses sequential cracking of ethanol and hydrocarbon wherein ethanol converts to ethylene in a first reaction zone and hydrocarbons to light olefins in a reaction zone in a single riser. Usually, the riser bottom temperature and pressure are very high, ethanol over cracks to lighter gas. In case severity at riser bottom is less, conversion of hydrocarbon to lighters will also be less.
Further, U.S. Pat. No. 5,981,819 discloses a process (Propylur process) that employs adiabatic fixed bed type, similar to that employed in a claus unit, to convert olefin streams of C4 hydrocarbon to light olefin using ZSM-5 type of catalyst.
Other than aforementioned described prior-art processes, methanol conversion processes are also employed to produce light olefins e.g. propylene and ethylene. These conversion processes are characterized by a high exothermicity, depending especially on the methanol conversion rate. These processes employ mostly fixed bed reactor configuration and reactor design is determined by heat control and removal of heat from the process. As it is fix bed process, it needs regeneration in regular frequency.
U.S. Pat. No. 4,627,911 discloses a heat neutral cracking process where exothermic methanol cracking and endothermic gas oil cracking are combined to achieve heat neutrality. The process as disclosed in aforementioned patent is executed without regenerating the catalyst. However, this process requires methanol to be injected preferably upfront of the gas oil to increase the catalyst temperature before gas oil cracking. Also the residence time required in the riser is much higher >6-15 sec with corresponding low WHSV of ˜25 hr−1. However, to maximize light olefin, it is necessary to minimize riser residence time to minimize H-transfer reactions. Further, the higher temperature (>550° C.) overcracks the methanol leading to unwanted dry gas formation.
Bernhard Lucke et al. (Microporous and Mesoporous Materials 29 (1999) 145-157) disclose a method for simultaneous conversion of C4/N-hexane/naphtha and methanol over ZSM-5 zeolite based catalyst in a fix bed configuration. The combination of endothermic cracking of hydrocarbons and exothermic cracking of methanol having suitable weight ratio produces light olefins under thermally sustained conditions. However, the co-feeding of hydrocarbons and methanol results in 100% conversion of methanol, but less conversion of hydrocarbon. Bernhard further discloses that higher reaction severity increases hydrocarbon conversion, but over cracks olefin to methane. Perhaps, higher temperature and higher residence time over cracks methanol to lighter like methane. However, the co-feeding of hydrocarbons and methanol does not give optimum conversion of both methanol and hydrocarbon and optimum selectivity towards olefins.
Therefore, a process of catalytic conversion of hydrocarbon feedstock having wide range of hydrocarbon feeds in the single riser to produce high yield of lower olefins is provided in the present disclosure wherein the drawbacks of related prior-art processes such as use of a dual reactor system, ill production of desired light olefins and deactivation of catalyst are obviated successfully.

Process for catalytic conversion of low value hydrocarbon streams to light olefins


A trocar for use in surgical procedures including a cannula for maintaining a sealed working channel in a body wall and an obturator which creates the working channel through the body wall while protecting patients and medical personnel from harm is disclosed. A cannula converter which can be employed with the trocar to enable a surgeon to use surgical instruments having a smaller outer diameter than the inner diameter of the cannula without deflating a body cavity is further disclosed. A site stabilizer which can be used with the trocar to prevent the cannula from being inadvertently withdrawn from the body cavity during a surgical procedure is also disclosed.

Medical science has long sought ways to minimize the dangers and trauma inherent in invasive surgical procedures. To this end, surgical techniques and instruments have been developed which, among other things, reduce the size of the incisions required to perform various surgical procedures. These techniques and instruments have been remarkably successful. Indeed, surgical procedures which only a few years ago would require an incision six or seven inches in length are today being performed through incisions which are less than one inch in length.
Trocars are one type of surgical instrument which have significantly contributed to these advances. In general, trocars are sharp, pointed surgical instruments which can be used to create and maintain small, hole-like incisions in a body cavity. Surgical instruments, including miniaturized optical devices, can be inserted through these small incisions and manipulated to perform surgical procedures within the body cavity without ever exposing the patient's internal organs or structures to the outside environment. Thus, by enabling the creation and maintenance of small working holes within a patient's body wall, conventional trocars have greatly contributed to the reduction in size of the incisions required to perform surgical procedures and reduced the related complications.
Conventional trocars generally include an obturator and a cannula. An obturator is a sharp, nail-like structure for penetrating a body wall to create a working channel into the body cavity. A cannula is a tube-like structure which can be inserted into the incision made by the obturator to maintain the working channel even after the obturator is removed. In the typical scenario, the obturator and cannula are assembled into a single unit (i.e., by inserting the obturator into the cannula) and then used to puncture the body wall. The obturator can then be carefully withdrawn from the cannula without removing the cannula from the body wall. Surgical instruments can be inserted through this cannula to perform an entire surgical procedure within the body cavity as mentioned above.
While conventional trocars plainly have many benefits, they also present significant hazards to both patients and medical personnel. For example, a patient is placed at risk of serious injury by the manner in which the trocar is employed. Specifically, in order to insert a trocar into a patient, a physician must overcome the resistance of the patient's body wall by exerting a significant amount of pressure on the trocar. When the obturator tip passes beyond the body wall the resistance suddenly reduces significantly. Thus, unless the physician immediately stops applying force, the trocar can move rapidly forward and possibly puncture or tear delicate internal organs. Since, the drop in resistance often occurs very suddenly, it can be very difficult to remove the force before injury occurs.
Medical personnel and patients are also placed at risk by the sharp tips of conventional trocars. Specifically, the sharp trocars make it very easy for medical personnel to inadvertently cut themselves or otherwise puncture their skin or gloves when using a conventional trocar. Not only are such accidental wounds painful, but they can also transfer the blood of the patient to the injured medical personnel or vice versa. With the increasingly widespread threat of HIV, the well-publicized AIDs virus, and other communicable diseases, the danger of accidental blood exchanges provides a clear danger to anyone involved with a conventional trocar. This is especially true when medical personnel are injured in a surgical setting since the patient's blood will likely be present when the accidental wound occurs. An accidental wound to a medical worker could, therefore, easily result in accidental blood exchanges between the injured party and the patient.
In addition to the serious risks detailed above, conventional trocars cause medical personnel many other problems. For instance, in many surgical procedures involving trocars, the body cavity is inflated with a nontoxic gas before the trocar is employed to create a working "pocket" or volume within the patient and to prevent the trocar from penetrating internal organs during insertion. For example, in an appendectomy, a patient's abdomen is first inflated with gas through a veress needle. The obturator is then used to place cannulas in various locations about the inflated abdomen for performing the procedure. One such cannula would typically be used to pass a small camera and light into the body cavity so a surgeon could view the operating area within the patient. Other cannulas would be used to pass surgical instruments into the cavity and remove tissue such as the appendix from the patient.
It is very important to maintain the abdomen of the patient in an inflated state throughout the procedure. To this end, conventional cannulas are often provided with sealing flap valves or the like which prevent gas from escaping from the patient's abdomen after the obturator is withdrawn. However, these sealing flap valves do not prevent gas leakage when a surgical instrument having a diameter which is smaller than the diameter of the cannula is employed. Instead, gas can easily pass through the gap between the inner wall of the cannula and the outer surface of the surgical instrument and deflate the work area. To prevent deflation of this type from occurring, physicians have often been required to utilize only those instruments whose dimensions closely match those of the cannula. This requirement inherently limits the surgeon's freedom of choice in selecting instruments for a procedure. Thus, while a certain instrument might be preferred by a physician, the physician might nonetheless be forced to use a less preferred (and possibly less effective) tool to perform a procedure to avoid deflating a body cavity.
Another problem conventional trocars present lies in the ease with which conventional cannulas can be inadvertently withdrawn from the working channel. Conventional cannulas typically include a smooth outer wall designed to facilitate insertion of the device through a body wall. The smooth surface of the cannula insures that the tissue surrounding the incision does not suffer excessive trauma when the cannula is passed through the body wall. Unfortunately, it also insures that the cannula can be withdrawn from the incision as smoothly and easily as it was inserted. This lack of resistance to withdrawal can easily result in the inadvertent withdrawal or removal of the cannula when an obturator or other surgical instrument is withdrawn. Inadvertent removals can create multiple problems, including deflation of the body cavity, splattering of body fluids, loss of time, and unnecessary trauma to the body tissue surrounding the working channel from the resulting multiple removals and insertions of the cannula.


A semiconductor memory device according to the invention includes a memory cell array (8) connected to a data bus through a first selector circuit (6), a second selector circuit (7) responsive to a first control signal (.phi. 0, .phi. X), a third selector circuit (8) responsive to a second control signal (.phi. 1 to .phi. 8), a row address buffer (17) responsive to activation of a row address strobe signal, an address fetching circuit (21) for instructing fetching of a column address every time of a specified number of toggled CAS signals, a column address buffer (19) responsive to a third control signal from the address fetching circuit (21), a nibble decoder (38) for generating the first and the second control signals, and a gate control circuit (39). A column address used to access a next memory cell is fetched during an activating period of the row address strobe signal after the column address is fetched.

Dynamic RAMs (hereinafter referred to as DRAMs) have been recently required to be usable in a flexible manner in a variety of modes. There are nibble mode type of DRAMs that are available which are designed to simultaneously read data consisting of a plurality of bits of data to a plurality of pairs of bus lines, and to output the data read out to the respective pairs of bus lines one by one in order to increase a data reading speed. There are proposed a variety of extended nibble modes in the nibble mode type of DRAMs.
A DRAM of the conventional nibble mode type is shown in FIG. 14. A memory cell array 11 includes a plurality of memory cells. To the array 11 are connected a row decoder 12, a sense amplifier and input/output (I/O) gate 13, and a column decoder 14. To the sense amplifier and I/O gate 13 is connected a gate circuit 15, to which is connected a data output buffer 16.
To the row decoder 12 is connected a row address buffer 17, which feeds to a row decoder 12 an external address signal AD including a plurality of bits input from an unillustrated controller unit.
A row controller 18 controls the row decoder 12 and the row address buffer 17 based on the levels of a row address strobe signal RAS and a column address strobe signal CAS, both serving as address activating signals.
To the column decoder 14 is connected a column address buffer 19, which feeds to the column decoder 14 an external address signal AD including a plurality of bits input from the controller.
A column controller 20 controls the sense amplifier and I/O gate 13, the column decoder 14, and the column address buffer 19 based on the level of an output signal of an AND circuit 21 to which a control signal RASZ from the row controller 18 and the column address strobe signal CAS are input.
A clock generating circuit 22 including an odd number of inverter circuits receives the column address strobe signal CAS, and outputs to a nibble counter 23 a clock signal CLK having a negative phase to the signal CAS as shown in FIG. 17. The nibble counter 23 counts the clock signal CLK input from the clock generating circuit 22, and outputs its counted result to a nibble decoder 24. The nibble decoder 24 decodes a counted value of the nibble counter 23, and outputs to a gate control circuit 25 control signals .phi. A to .phi. D shown in FIG. 17.
The gate control circuit 25 takes an AND (logical product) of the control signals .phi. A to .phi. D from the nibble decoder 24 and the clock signal CLK from the clock generating circuit 22, and outputs control signals .phi. 11 to .phi. 14 shown in FIG. 17 to the gate circuit 15 so as to control the gate circuit 15.
A data input buffer 26 is connected to the sense amplifier and I/O gate 13, and receives a write data Din based on a control signal from an unillustrated write clock generator.
FIGS. 15 and 16 show in detail the memory cell array 11, the sense amplifier and I/O gate 13, the gate circuit 15, and the data output buffer 16. As shown in FIG. 15, a data bus 30 includes four pairs of data bus lines DB0, DB0 to DB3, DB3, to which pairs of bit lines BL0, BL0 to BL3, BL3 are connected, respectively. The pairs of bit lines BL0, BL0 to BL3, BL3 are connected to memory cells 32 each having one end thereof connected to a word line WL through gate transistors T1 and a sense amplifier 31.
On the respective pairs of data bus lines DB0, DB0 to DB3, DB3 are arranged amplifiers 33. Gate circuits 15 each including nMOS transistors T2, T3 are provided at the output sides of each amplifier 33 as shown in FIG. 16. The control signal .phi. 11 is input to gates of the nMOS transistors T2, T3 arranged on the pair of bus lines DB0, DB0. The control signal .phi. 12 is input to gates of the nMOS transistors T2, T3 arranged on the pair of bus lines DB1, DB1. The control signal .phi. 13 is input to gates of the nMOS transistors T2, T3 arranged on the pair of bus lines DB2, DB2. The control signal .phi. 14 is input to gates of the nMOS transistors T2, T3 arranged on the pair of bus lines DB3, DB3.
Each of the data bus lines DB0 to DB3 are connected to a common inverter circuit 34 after the transistors T2, while the data bus lines DB0 to DB3 are connected to a common inverter circuit 35 after the transistors T3. The data output buffer 16 includes nMOS transistors T4, T5 connected in series between a power supply VCC and a ground GND. The inverter circuit 34 is connected to a gate terminal of the transistor T4 while the inverter circuit 35 is connected to a gate terminal of the transistor T5. The data output buffer 16 outputs an output signal Dout in the form of a logic value "1" or "0" in accordance with output signals of the inverter circuits 34, 35.
In the DRAM thus constructed, a read cycle is started if the column address strobe signal CAS is in the high level (H-level) when the row address strobe signal RAS is switched to a low level (L-level) as shown in FIG. 17. After either one of the word lines WL is selected in accordance with a row address ADR of the address signal AD, a column address ADC is fed and a column selection signal CL0 turns to H-level. Thereupon, data written in the specified memory cells 32 on the respective pairs of bit lines BL0, BL0 to BL3, BL3 are, via each gate transistor T1 output to the corresponding pairs of data bus lines DB0, DB0 to DB3, DB3, and each data is amplified by the amplifiers 33 respectively.
Then, the control signals .phi. 11 to .phi. 14 are generated by the gate control circuit 23 based on the clock signal CLK from the clock generating circuit 22 and the control signals .phi. A to .phi. D from the nibble decoder 24. Upon receipt of the control signals .phi. 11 to .phi. 14, the transistors T2, T3 arranged on the pairs of data bus lines DB0, DB0 to DB3 are turned on, and thereby the data read out through the data bus lines DB0, BD0 to DB3, DB3 are output through the data output buffer 16 sequentially.
However, in the prior art DRAM, as shown in FIG. 17, the column address ADC of the address signal latched at leading edges of the row address strobe signal RAS and the column address strobe signal CAS is set as an initial address of the nibble counter 23 in the same cycle defined between a fall of the row address strobe signal RAS and a rise thereof. Further, the column selection signal CL0 is maintained in the H-level so as to read out the data to the pairs of data bus lines DB0, DB0 to DB3, DB3. Accordingly, when the addresses corresponding to the number of bits constituting the nibble counter 23 (normally, four bits) are changed from an initial address, the address returns to the initial address, with the result that the output signal Dout outputs again the same data repeatedly.
In order to prevent the same data from being repeatedly output, the read cycle is started by changing the row address strobe signal RAS to the L-level immediately after changing the same to the H-level at the time when the addresses corresponding to the number of bits constituting the nibble counter 23 (normally, four bits) are changed. However, according to this method, it takes time until the first data is output as shown in FIG. 17, thereby suffering the problem of being incapable of increasing a data reading speed.


Molten aluminum and a ceramic substrate are held in direct contact with each other and thereafter cooled to have the aluminum joined directly to the ceramic substrate. This method is capable of consistent and easy production of aluminum-ceramics composite substrates having satisfactory joint strength, thermal conductivity and heat resistance characteristics. A ceramic member is fed successively into and through molten metal to directly bond the metal on the ceramic to produce a metal-bonded-ceramic (MBC) material at a low cost. An electronic circuit substrate made of an aluminum ceramic composite material wherein an electronic circuit is formed on an aluminum surface of the aluminum-ceramic composite material. The aluminum-ceramic composite material is made by directly solidifying molten aluminum or an aluminum alloy on at least a portion of a ceramic substrate.

1. Field of the Invention
This invention relates to a process for producing ceramic substrates having metals joined thereto. More particularly, the invention relates to a process for producing aluminum or aluminum alloy-ceramics composite electronic circuit boards suitable for mounting highpower electronic devices such as power modules.
This invention further concerns a process for producing rugged metal-bonded-ceramic (MBC) material or components. Particularly the present invention is directed to an industrial process for producing MBC material or components of metals with oxide, nitride or carbide ceramics that are suitable for use in automotive parts, electronic parts, etc. The invention also is directed to MBC plates produced by such process, as well as electronic circuit substrates fabricated from such MBC plates.
2. Background Information
Metal-ceramics composite electronic circuit boards which have metals joined to the surface of ceramic substrates are commonly used for mounting high-power devices such as power modules. To make such composite circuit boards, copper, which has high electrical and thermal conductivities, is joined to alumina or aluminum nitride ceramics.
MBC components are extensively used in automobiles, electronic equipment and other applications by taking advantage of the chemical stability, high melting points, insulating property and high hardness of ceramics in combination with the high strength, high toughness, free workability and conducting property of metals. Typical applications of the components include rotors for automotive turbochargers, as well as substrates and packages for mounting large-power electronic elements.
MBC material and MBC components are known to be produced by various methods including adhesion, plating, metallizing, thermal spraying, brazing, direct bonding or "DBC", shrink fitting and casting.
Adhesion is a process in which a metal member is joined to a ceramic member with an organic or inorganic adhesive.
Plating is a process that comprises activating the surface of a ceramic member and dipping it in a plating bath to apply a metal plate.
Metallizing is a process that comprises applying a paste containing metal particles to the surface or a ceramic member and sintering it to form a metal layer.
Thermal spraying is a process in which molten metal (or ceramic) drops are sprayed onto the surface of a ceramic (or metal) member so that a metal (or ceramic) layer is formed on that surface.
The direct bonding process (DBC) has been developed for the particular purpose of joining copper to oxide ceramics. In the DBC method, an oxygen-containing copper member sheet is heated in an inert gas atmosphere while it is joined to a ceramic member or, alternatively, oxygen-free copper is heated in an oxidizing atmosphere, to join copper to a ceramic member, i.e., the surface of an oxygen-free copper member is first oxidized to form a copper layer then joined to a ceramic member. Thus in order to join copper to non-oxide ceramics by the DBC method, an oxide layer must first be formed on the surface of a non-oxide ceramic substrate. As disclosed in Unexamined Published Japanese Patent Application (Kokai) No. 3077/1984, an aluminum nitride substrate is first treated in air at a temperature of about 1000.degree. C. to form an oxide on the face of the substrate and the direct bonding method is then applied to join copper to the aluminum nitride.
In brazing, copper is joined to ceramics with the use of an intermediary brazing material containing an active metal. The most common brazing material used in this method is based on a Ag--Cu--Ti system.
Brazing is a process in which metal and a ceramic member are joined with the aid of a low-melting point filler metal or alloy. To insure that the filler metal or alloy is securely joined to the ceramic member, a metal component highly reactive with ceramics is added or a metal layer is preliminarily formed on the joining surface of the ceramic member by a suitable method such as metallizing or thermal spraying.
In shrink fitting, the ceramic and metal members to be joined are provided with a projection and a cavity, respectively, in such a way that the outside diameter of the projection is equal to the inside diameter of the cavity and the metal member is heated to expand the cavity, into which the projection of the ceramic member is inserted; thereafter, the two members are cooled so that they form an integral assembly in which the projection on the ceramic member is nested in the cavity in the metal member.
Casting is similar to shrink fitting, except that a metal is cast around a ceramic member and cooled so that it shrinks to have the ceramic member nested as an integral part.
These prior art methods, however, have problems. Adhesion produces composites that are low in adhesion strength and heat resistance. The applicability of plating, metallizing and thermal spraying is usually limited to the case of forming thin metal (or ceramic) layers whose thickness ranges from a few microns to several tens of microns.
Shrink fitting and casting are applicable only to a special case in which at least part of a ceramic member is to be nested in a metal.
In DBC, copper is the only metal that can be joined and the temperature for joining must be within a narrow range close to the eutectic point of Cu--O and, hence, there is a high likelihood for the development of joining defects such as swelling and incomplete joining.
Brazing uses expensive filler metals or alloys and requires the joining operation to be performed in a vacuum and, hence, the operational cost is high enough to prevent the use of the method in a broad range of applications.
In spite of their widespread use, the copper-ceramics composite substrates have several problems associated with production and practical use. The most serious problem is that cracks can develop in the ceramic substrates during mounting electronic components and during their subsequent use, whereupon dielectric breakdown may occur across the thickness of the substrate.
In order to join copper to ceramic substrates, they are heated to almost 1,000.degree. C. and, in addition, the copper-ceramics composite substrate is heated to almost 400.degree. C. when mounting electronic components such as power modules. The thermal expansion coefficient of copper is higher than that of ceramics by a factor of about 10, so when the composite substrate is cooled to room temperature, the thermal expansion mismatch will cause a substantial thermal stress within the substrate.
Furthermore, on account of the environment in which the electronic components are used, as well as the heat generated during their use, the temperature of the composite substrate is subject to constant changes, which cause corresponding changes in the thermal stress on the substrate. Such thermal stresses contribute to cracking in the ceramic substrate. One of the important parameters for evaluation of ceramic electronic circuit boards is resistance to heat cycles, or the number of thermal swings between -40.degree. C. and 125.degree. C. that can be applied to the circuit board until cracking occurs. Copper-alumina composite substrates fabricated by the direct bonding method can withstand 20 such heat cycles but, on the other hand, similar substrates fabricated by brazing can withstand only 10 heat cycles or less.
Aluminum has comparable electrical and thermal conductivities to copper and the idea of using aluminum as a conductive circuit material has been known for many years (see, for example, Unexamined Published Japanese Patent Application (kokai) No. 121890/1984, which discusses such idea). Aluminum is softer than copper and its yield strength is about a quarter of the value for copper. Therefore, it is anticipated that the residual stress in the composite substrates could be markedly reduced by using aluminum as a circuit material. However, Unexamined Publication Japanese Patent Application (kokai) No. 121890/1984, supra, do not disclose a specific method of joining aluminum to ceramics.
Unexamined Published Japanese Patent Application (kokai) Nos. 125463/1991, 12554/1992 and 18746/1992 disclose methods of fabricating aluminum-ceramics composite substrates by brazing. According to these published Japanese patent documents, the fabricated aluminum-ceramics composite substrates can withstand at least 200 heat cycles, which is about 10 times as great as the value for the copper-ceramics composite substrate.
However, the aluminum-ceramics composite substrates that are produced by the methods disclosed in the published Japanese patent documents listed above have the following problems associated with their manufacture or subsequent use:
(1) Aluminum is highly prone to be oxidized, so the methods at issue have to be carried out in either in vacuo or in an atmosphere filled with an inert gas of high purity.
(2) The melting point of aluminum is as low as 660.degree. C., so if the brazing temperature approaches this level, aluminum will either totally melt to lose its shape or partly melt to induce a brazing defect called "nibbling". On the other hand, if the brazing temperature is unduly low, the brazing material will not completely react with the ceramics and the resulting composite will have only a small strength. As will be described hereinabove in the Examples, the use of a brazing alloy of an Al--Si system requires that brazing be carried out within a temperature range even narrower than the range from 590.degree. C. to 640.degree. C. According to the experience of the present inventors, controlling the temperature in a heating furnace to reach uniformity is very difficult to accomplish in large-scale production, particularly in the case where composite substrates are to be produced in vacuo (because the heat from a heating element is transmitted solely by radiation and conduction in the absence of convection).
(3) When composite substrates are to be fabricated by brazing, the brazing temperature must not be higher than the melting point of aluminum (660.degree. C.). However, the aluminum-based brazing material wets the ceramics only poorly at such low temperatures. Thus, failures in joining often occur if composite substrates are produced by brazing.
(4) An alumina substrate is amenable to direct brazing. However, an aluminum nitride ceramic substrate requires that its surface be oxidized as in the case of direct joining of copper. However, this is not desirable for the following two reasons: first, the overall process becomes complicated; second, the aluminum nitride substrate has been developed in order to meet the requirement for better thermal conductivity, but an oxide formed on the surface is, of course, detrimental to the thermal conduction characteristics.
(5) As in the case of copper-ceramics composite substrates, the aluminum-ceramics composite substrates fabricated by brazing would have a lower resistance to heat cycles than those fabricated by direct bonding. This is because the brazing alloys used in the fabrication of the substrates are harder than pure metals and will not readily undergo plastic deformation, thus causing untoward effects on stress relaxation.
As described above, the process of fabricating aluminum-ceramics composite substrates by brazing has several problems including instability. If the ceramic substrate is based on a non-oxide, the manufacturing process is complicated. Furthermore, the composite substrates fabricated by the prior art processes are not always considered to be optimal with respect of joint strength and heat resistance characteristics.
As already hereinabove, MBC components can be used as substrates for mounting large-power electronic elements. Currently used MBC substrates comprise ceramic substrates having copper circuit patterns formed on the surface. Depending on the kind of the ceramic substrate used and the process for producing the MBC substrates, commercial composite substrates are classified as copper/alumina directly joined substrates, copper/aluminum nitride directly joined substrates, copper/alumina brazed substrates and copper/aluminum nitride brazed substrates.
A method for producing copper/alumina directly joined substrates is described in Unexamined Published Japanese Patent Application (kokai) Sho-52-37914. In Sho-52-37914, an oxygen-containing copper plate is superimposed on an alumina substrate or, alternatively, an oxygen-free copper plate is heated in an oxidizing atmosphere to generate copper oxide on the surface of the oxygen-free copper plate, before the copper plate is joined to the alumina substrate with a composite oxide of copper and aluminum being formed at the interface.
To produce copper/aluminum nitride directly joined substrates, an oxide must first be formed on the surface of an aluminum nitride substrate. A method of production is described in Unexamined Published Japanese Patent Application (kokai) Hei 3-93687. In Hei 3-93687 the aluminum nitride substrate is first treated in air at a temperature of about 1,000.degree. C. to form an oxide layer on the surface and, then, a copper plate is joined to the aluminum nitride substrate with an intermediate oxide layer, by the method described in the preceding paragraph.
To produce copper/alumina or aluminum nitride brazed substrates, a copper plate is joined to a ceramic substrate with the aid of a low-melting point filler metal. A commonly used filler metal is made from an alloy comprising Ag, Cu and Ti. In this case the purpose or adding Ag is to lower the melting point and the purpose of adding Ti is to enhance the wettability of the filler metal to ceramics.
In spite of their common use, copper/ceramic composite substrates have several problems that are encountered during fabrication and actual use. The most serious problem is that cracks develop in the ceramic substrate during the mounting of electronic element and during the use of thus assembled electronic devices. This defect is attributable to the thermal expansion coefficient of copper, which is higher than that of ceramics by about one order of magnitude.
During the joining operation, both the ceramic substrate and copper are heated to about 1,000.degree. C. and as they are cooled from the joining temperature to room temperature, considerable thermal stress therefore develops within the MBC substrate due to the thermal expansion difference. When mounting electronic elements on MBC substrates, the latter are heated to about 400.degree. C. and also the temperature of the MBC substrate constantly change due to the temperature change in the operating environment or due to the generation of heat during the use of the assembled electronic devices, whereby the MBC substrates are subjected to varying thermal stresses. On account of these thermal stresses, cracks develop in the ceramic substrate.
An important factor regarding the evaluation of the MBC substrates is resistance to heat cycles. This factor is expressed by the number of times a substrate can be subjected to repeated heating and cooling cycles between -40.degree. C. and 125.degree. C. without developing cracks due to thermal stresses. The copper-bonded-ceramic substrates can withstand only several tens of heat cycles under the indicated conditions. Moreover, in order to acquire resistance to the heat cycles, the thickness of the ceramic substrate has to be greater than the sum of the thicknesses of copper plates joined to both principal surfaces of the ceramic substrate. This means that the thickness of the ceramic substrate must be increased beyond the value necessary to maintain its inherent electrical insulating property. As a result, heat conduction, which is another important characteristic of the MBC substrates, is sacrificed.
In recent years, the development of power modules for installation on electric cars has increased the demand for MBC substrates having improved resistance to heat cycles. Under severe use conditions as in electric cars where temperatures changes are violent and great vibrations occur, resistance to 3,000 heat cycles and more is said to be necessary. However, this requirement cannot be met by the copper-bonded-ceramic substrates in current use.
Aluminum is as good an electric and heat conductor as copper and the idea of using it as a conductive circuit material is described in Unexamined Published Japanese Patent Application (kokai) Sho 59-121890. Generally brazing is used to join aluminum and ceramics and Unexamined Published Japanese Patent Applications (kokai) Hei 3-125463, Hei 4-12554 and Hei 4-18746 teach aluminum-ceramic substrates produced by brazing. These substrates can withstand about 200 heat cycles, but they are still unsuitable for use in electric cars and in other applications where very high resistance to heat cycles is required. As a further problem, brazing must be conducted in a vacuum and nonoxide ceramics must be subjected to a preliminary treatment for forming an oxide on the surface and this makes the brazing process unsatisfactory in terms of not only production cost, but also heat conduction.
Thus, the prior techniques for joining metal and ceramic members have had one or more of the following problems:
(1) the metal and ceramic members to be joined are limited to those having certain shapes;
(2) the joining step is costly and limited in the scope of applications; and
(3) the joined members do not meet the performance requirements for joint strength, heat resistance and resistance to heat cycles.

Process for preparing a ceramic electronic circuit board and process for preparing aluminum or aluminum alloy bonded ceramic material


A wiring substrate includes a wiring layer, an outermost insulating layer laminated to the wiring layer, and a pad electrically connected to the wiring layer and exposed from a surface of the outermost insulating layer. The pad consists essentially of a first metal layer and a second metal layer. The first metal layer includes a first surface, which is exposed from the surface of the outermost insulating layer, and a second surface, which is located opposite to the first surface. The second metal layer includes is formed between the second surface of the first metal layer and the wiring layer. The first metal layer is formed from a metal selected from gold or silver or from an alloy including at least one of gold and silver. The second metal layer is formed from palladium or a palladium alloy.

The present invention relates to a wiring substrate and a method for manufacturing a wiring substrate.
In the prior art, in order to achieve a high density wiring pattern for a wiring substrate used in a semiconductor package or the like, a build-up wiring substrate is known in which a build-up wiring layer and an insulating layer are laminated on upper and lower surfaces of a core substrate.
The density of semiconductor chips mounted on build-up wiring substrates have become high. Thus, there is a demand for build-up wiring substrates that further increase the wiring pattern density and reduce the substrate thickness. In a build-up wiring substrate, the layered portion of a wiring layer and insulating layer can be formed thinly through a build-up process. However, the portion of a core substrate is required to have a suitable thickness in order to provide the wiring substrate with rigidity. Consequently, there have been limits on the extent to which the thickness of the entire wiring substrate can be reduced. Thus, a so-called careless substrate has been proposed, which is a wiring substrate that excludes the core substrate (support member) to further reduce the thickness of the wiring substrate (refer to, for example, Japanese Patent Application Publication No. 2000-323613).
The basic processing for a coreless substrate prepares a provisional substrate as a support body, forms a pad on the provisional substrate, laminates a desired number of build-up wiring layers and insulating layers, and finally removes the provisional substrate. In such a coreless substrate, unlike a conventional build-up wiring substrate, there is no core substrate. Thus, the thickness of the wiring substrate can be reduced.
A pad formed on the support body generally has a laminated structure including a plurality of metal layers. Such a typical laminated structure may be a two-layer structure, which includes a gold (Au) layer and a nickel (Ni) layer, or a three-layer structure, which includes an Au layer, a Pd layer, and an Ni layer. A pad having such a structure has superior wire bonding properties. However, when the pad is connected to lead (Pb)-free solder, the Ni forms a trialloy with tin (Sn) and copper (Cu). This decreases the drop impact resistance.
Another typical laminated structure is a two-layer structure formed by an Organic Solderability Preservative (OSP) process including a film (OSP film) of water-soluble preflux and a Cu layer. In a pad having such a structure, the drop impact resistance does not decrease. However, since no Ni is present, the OSP film is prone to oxidization and discoloration.

Wiring substrate and method for manufacturing wiring substrates


Methods of controlling insects include applying at least one spinosyn compound to a locus of a neonicotinoid-resistant insect, such as a strain of Drosophila melanogaster resistant to a neonicotinoid compound. The spinosyn compound may be a mixture of spinosyn A and spinosyn D. The spinosyn compound may cause up to approximately ten times increased mortality in the neonicotinoid-resistant insect compared to an insect susceptible to a neonicotinoid compound.

Spinosyn compounds are broad spectrum insecticides known to have insecticidal activity toward insects that are pests and cause damage to crops. Spinosyn compounds are manufactured using a fermentation process in which Saccharopolyspora spinosa colonies are grown using natural products, such as soybean and cottonseed meal. Neonicotinoid compounds are compounds that have been used as insecticides for over twenty years. Neonicotinoid compounds, such as imidacloprid, are one of the top selling classes of insecticides. However, over the years, insects have begun to develop resistance to neonicotinoid compounds. The development of resistance to insecticides is well known. There are estimated to be at least 400 species of arthropods that are resistant to one or more insecticides.
Insecticides affect a specific target site of the insect, such as a protein. Many insecticides acting at identified target sites are losing effectiveness due to increased resistance in field populations of the insects. Spinosyn compounds and neonicotinoid compounds are believed to act at different subtypes of nicotinic receptors. While spinosyn compounds are allosteric modulators at the nicotinic acetylcholine receptor (nAChR), neonicotinoid compounds are agonists at the nAChR. Spinosyn compounds act at a distinct site from the target site of the neonicotinoid compounds.

This patent is subject to a terminal disclaimer.


The invention is a portable power supply having a built in battery, switch matrix, external voltage and impedance sensing means, inverter, and charging circuitry. The device uses a power plug for receiving AC from a wall electric receptacle; a transformer for transforming high voltage input to a low voltage output; a rectifier, for rectifying the low alternating voltage to direct voltage; at least one battery rechargeable by said direct voltage; an inverter, for inverting direct voltage supplied by the rechargeable battery to relatively low alternating voltage, which is supplied to the secondary winding of the transformer; and an alternating current (AC) socket, for receiving high voltage from the primary winding of the transformer. Both AC and DC of various voltages may be supplied by this device in a portable manner, which uses a single transformer both for recharging batteries and for supplying AC power produced via the batteries. A switching assembly allows for connecting the batteries (which may be rechargeable) in a variety of topologies.

Technical Field
The present invention relates to the field of power supplies. More particularly, the invention relates to a method and apparatus for a multi-functional power supply.
Description of Related Art
Electronic devices generally require a certain specific input voltage at a given polarity and maximum current draw. Generally each device will therefore require a separate power supply
There is thus a long felt need to provide a general power supply, capable of supplying power to various devices by one single apparatus.
It is an object of the present invention to provide a solution to the above-mentioned and other problems of the prior art. Other objects and advantages of the invention will become apparent as the description proceeds.

System, method and apparatus for portable power supply


The present invention relates to recombinant blood coagulation factor IX (rFIX) mutants having factor VIII (FVIII) independent factor X (FX) activation potential. Five full length FIX proteins with combinations of mutations of amino acids important for functional activity of FIX and FIX wild type were cloned and expressed in HEK 293 cells. The proteins were tested by an activated partial thromboplastin time (aPTT) assay in FVIII-depleted plasma as well as in FVIII-inhibited patient plasma. In FVIII-depleted plasma functional activity of the FIX mutants was calculated as increased FVIII equivalent activity. The mutant proteins had increased FVIII equivalent activity. In FVIII-inhibited patient plasma the FEIBA equivalent activity was calculated for analysis of FVIII independent FX activation potential. The proteins had also increased FEIBA equivalent activity. Furthermore, the pre-activated FIX proteins had an increased activity in FIX-depleted plasma containing FVIII inhibitors. Therefore these FIX mutants are alternatives as bypassing agents for treatment of FVIII inhibitor patients.

The blood coagulation cascade involves a series of serine protease enzymes (zymogens) and protein cofactors. When required, an inactive zymogen precursor is converted into the active form, which consequently converts the next enzyme in the cascade.
The cascade is divided into three distinct segments: the intrinsic, extrinsic, and common pathways (Schenone et al., Curr Opin Hematol. 2004; 11:272-7). The activation of factor X (FX) is the common point of the intrinsic and extrinsic pathways. The activation occurs either by the extrinsic complex formed by activated factor VII (FVIIa) and tissue factor, or by the intrinsic tenase complex composed of activated Factor IXa (FIXa) and activated Factor VIIIa (FVIIIa) (Mann, Thromb. Haemostasis 1999; 82:165-74).
Activated FX along with phospholipids, calcium, and factor Va (FVa) then converts prothrombin to thrombin (prothrombinase complex), which in turn cleaves fibrinogen to fibrin monomers. The monomers polymerize to form fibrin strands. Factor XIIIa (FXIIIa) covalently bonds these strands to one another to form a rigid mesh.
Deficiencies of the components of the intrinsic tenase complex, FVIIIa and FIXa, lead to severe bleeding disorders, hemophilia A and B, respectively. Hemophilia A is considered the classic form of hemophilia, whereas hemophilia B is also known as Christmas disease. Hemophilia A and B are the consequence of congenital deficiencies of FVIII and FIX, respectively. The worldwide incidence of hemophilia A is approximately 1 case per 5,000 male individuals and of hemophilia B 1 case per 30,000.
Originally patients with severe hemophilia had a shortened lifespan and diminished quality of life that was greatly affected by hemophilic arthropathy. But life expectancy has increased from 11 years before the 1960s for patients who were severely affected to more than 50-60 years by the early 1980s. This has been accomplished through the widespread use of replacement therapy.
Nowadays the treatment of choice for the management of hemophilia A is replacement therapy with various plasma derived or recombinant FVIII concentrates. Although progress in the production of FVIII to ensure purity, efficacy and viral safety has been made over the past decades, some limitations remain. First of all, severe hemophilia A patients are frequently affected by anti-FVIII inhibitor antibody formation, thus rendering the therapy ineffective. Approximately 30% of patients with severe hemophilia A develop alloantibody inhibitors that can neutralize FVIII (Hay, Haemophilia 2006; 12 Suppl 6:23-9, Peerlinck and Hermans, Haemophilia 2006; 12:579-90). Furthermore, acquired hemophilia may occur which is the development of FVIII antibody inhibitors in persons without a history of FVIII deficiency.
Attempts to overwhelm the inhibitors with large doses of human FVIII have been tried. Also porcine FVIII which has low cross-reactivity with human FVIII antibody has been administered. More frequently, FVIII-bypassing agents, including FEIBA (factor eight inhibitor bypassing activity), FIX complex and FVIIa have also been used.
Modification of the functional activity of the tenase complex would also be an elegant approach to address several of the above discussed issues in hemophilia treatment, i.e., deficiency of FVIII or FIX and inhibitor development.
In the tenase complex FIXa has critical importance (Rawala-Sheikh et al., Biochemistry 1990; 29:2606-11). FIXa is a two-chain vitamin K-dependent serine protease capable of hydrolysing the Arg194-Ile195 peptide bond in the FX molecule which leads to its activation (Venkateswarlu et al., Biophys. J. 2002; 82:1190-206). Although this reaction can proceed slowly in solution, it is significantly accelerated in the presence of negatively charged phospholipid surfaces. In vivo, these surfaces are mainly provided by activated platelets and plasma lipoproteins. The rate of the reaction is increased further by the presence of FVIIIa.
FIXa exhibits very low catalytic activity in an in vitro system lacking either the co-factor FVIIIa or the physiologic substrate FX. This is in contrast to the closest related homologue, FXa, which shows significant activity towards peptide substrates (in addition to its physiologic substrate prothrombin), independent of its co-factor protein FVa. Thus the drawback of the sophisticated regulation of this enzymatic system is that failure of a single component such as FVIIIa or the development of inhibitors suffices to interrupt the functional activity of the tenase apparatus.
An improved FIX protein, which has improved FVIII-independent FX activation potential could avoid this issue. Several amino acid residues of FIXa are already known to be important for regulation of enzymatic activity and interaction with both FVIIIa and FX.
The surface loop 99 of FIXa is important for regulation of FIXa activity (Hopfner et al., Structure Fold Des. 1999; 7:989-96). In the non-complexed FIXa this loop is stabilized in an inactive conformation and limits access of substrate to the catalytic machinery.
The mutations Y94F and K98T are located on the 99-loop, known to contribute to FX substrate binding by forming of the recognition site of the S2 and S4 pockets of FX. Y177F mimics the effect of activation by FVIIIa. Tyrosin 177 locks the 99-loop in an inactive conformation, which is released by binding of FVIIIa to FIXa (Sichler et al., J Biol Chem. 2003; 278:4121-26).
Val 213 and Gly 219 are conserved amino acids in most other trypsin-like proteases, and a double mutant of truncated FIX (I213V-E219G) expressed in E. coli showed increased amidolytic activity of FIXa (Hopfner et al., EMBO J. 1997; 16:6626-35).
However, in none of these publications full length FIX mutants expressed in mammalian cells showed an improved functional activity in a meaningful activated partial thromboplastin time (aPTT) assay in FVIII-depleted plasma or FVIII-inhibitor-patient plasma.
Thus, there remains a great need in the art for compositions and methods that provide an improved FIX molecule that can be used for treatment of patients with hemophilia A.
It was the inventive task of the present invention to develop novel FIX proteins by introduction of amino acid exchanges, which have improved FVIII-independent FX activation potential with coagulation FVIII activity useful for the treatment of bleeding disorders.

FVIII-independent FIX-mutant proteins for hemophilia A treatment


A retardation plate characterized by being obtained by laminating a homeotropic liquid-crystal film formed from a homeotropic liquid-crystal polymer of the side chain type or from a homeotropic liquid-crystalline composition comprising the side chain type liquid-crystal polymer and a photopolymerizable liquid-crystal compound to a stretched film having a retardation function. In the retardation plate, the retardation in the thickness direction can be regulated to a value in a wide range.

In image viewing displays, such as a liquid-crystal display, birefringence by a liquid crystal etc. varies contrast etc. in accordance with variation of viewing angles. In order to prevent such contrast variation etc., there are proposed in liquid-crystal displays such a technique that disposes a retardation plate in a liquid-crystal cell, compensates optical characteristics based on birefringence, and thereby improves viewing angle characteristics. Although uniaxially or biaxially stretched films etc. are usually used as retardation plates for compensation, they fail to provide a viewing angle characteristic that is satisfactory for all liquid-crystal cells.
Japanese Patent Laid-Open No.2000-304924 official report discloses a continuous method for producing a retardation plate in which one or more heat-shrinkable films are adhered on one side or both sides of a long film composed of a thermoplastic resin, the long film is shrunk, in a state of gripped by a tenter, by function of shrinking force of the heat-shrinkable film in a width direction at a ratio (A) of no less than 0.7 to less than 1.0 times, and subsequently the obtained film is stretched and widened in the width direction concerned at a stretching ratio (%) that satisfies an equation or less (100−ratio (A)×100)×0.15, when a width of the film excluding the gripped section after the shrinking process is defined as 100.
Since the method gives stretching also in a thickness direction, it may provide a retardation plate having retardation also in the thickness direction. However, in the producing method, when in-plane main refractive indexes of the retardation plate obtained are defined as nx and ny, and a refractive index in a thickness direction is defined as nz, and nx>ny, Nz defined by Nz=(nx−nz)/(nx−ny) is −1.0<Nz<0.1, and stretching in the thickness direction has limitations, which cannot control the retardation in the thickness direction over a wide range. A long heat-shrinkable film is used in the method, is stretched by heat contraction in a thickness direction, and therefore, a resulting retardation plate obtained has an increased thickness as compared with the original long film. A thickness of the retardation plate obtained by the method is about 50 to 100 micrometers, and is not enough, as thinness required of a liquid-crystal display etc.
The present invention aims at providing a retardation plate that enables control of retardation over a wide range in a thickness direction, and providing a method for producing the same. This invention also aims at providing an optical film using the retardation plate, and furthermore providing an image viewing display using the retardation plate and the optical film.

Retardation plate, process for producing the same, and optical film


A circuit module of a memory card is selectively used with card readers/writers compliant with different access protocols. The circuit module includes a shared non-volatile memory; a first transmission control unit communicable with a first card reader/writer for controlling data transmission from/to the first card reader/writer; a second transmission control unit communicable with a second card reader/writer for controlling data transmission from/to the second card reader/writer; and a data buffer and memory access controller coupled to the non-volatile memory and the first and second transmission control units for conducting a data transmission path between a designated transmission control unit and the non-volatile memory, thereby allowing data transmission between the designated card reader/writer and the non-volatile memory. The circuit module can be grouped with different carrier housings to produce a memory card kit.

With the increase in bit size of digital files processed by electronic apparatus such as a computer system or digital camera, storage problems raised. Small-capacity storage media like floppy discs have been not practical enough to store digital files likely of several million bytes. Hence, flash memory modules with compact size and large capacity up to a couple of gigabytes (GB) are taking the place of conventional storage media. For example, the high-capacity flash memory modules are widely used in computer systems and portable digital peripheral equipments such as digital cameras.
Nowadays, there have been many kinds of memory cards in use, e.g. compact flash (CF) card, memory stick (MS) card, smart media card (SMC), secure digital (SD) card, multimedia card (MMC), microdrive card, etc. Different kinds of memory cards are compliant with different access protocols established by different manufacturers. The interface specification, control chip, and package mechanism of different memory cards are unique and incompatible mutually. Thus various memory cards are required for different electronic apparatus or different uses. Furthermore, the data accessible by an electronic apparatus compliant with a first access protocol is possibly unable to be transferred to another electronic apparatus compliant with a second access protocol. For example, a digital camera designed for a compact flash card cannot communicate with a secure digital card, and a card reader supporting a secure digital card cannot access the data stored in a compact flash card. Therefore, 6-in-1, 7-in-1, or 8-in-1 card readers are developed to cover as many uses as possible. Some slots in the multi-card reader, however, are never used. Hence, it seems to be an inefficient and uneconomic solution.
Please refer to FIG. 1, which is a functional block diagram illustrating a conventional memory card. The memory card 1 mainly includes a flash memory 10 and a controller 11 enclosed with a housing 12. Generally, the basic configuration of the flash memory 10 of the memory card 1 is identical to any other kinds of memory card currently used. But the controller 11 is different from that adapted to different access protocol. The dimension and size of the housing 12 also varies according to the memory card specification. Hence, production lines would be complicated for producing various controllers. Further, the stocks of parts for various controllers may cause a problem in cost control.

Circuit module and memory card kit compliant with various access protocols


An optical filter is disclosed which adjusts the contours of blurred images and maintains the size of blurred images. The optical filter includes a substrate being substantially transparent and a first layer whose optical density changes continuously, formed on the substrate. A transmission rate of the first layer decreases substantially linearly from a center toward a periphery of the optical filter, and the transmission rate distribution is symmetric with respect to the center.

1. Field of the Invention
The present invention relates to an optical filter for obtaining a favorably out-of-focused image when taking photographs, as well as to a light amount adjusting apparatus and an image-taking apparatus to which such an optical filter is mounted.
2. Description of Related Art
In the past, technology has been disclosed related to optical filters for improving out-of-focused image, so-called blurred images which are not in focus and to cameras incorporating such optical filters. An example of such filters are apodization filters. Apodization filters are devised so that their transmission rate decreases with increasing distance from a center of the optical axis in directions perpendicular to the optical axis, and when such a filter is used, then the contours in a blurred image become smooth, and cross-eyed bokeh and ring bokeh are eased. Accordingly, in scenes in which the focus depth is small, such as when taking portraits or in macro photography, the background becomes a naturally blurred image with softened contours, attaining a high-quality image in which the focused main object looks attractive.
Regarding manufacturing methods and structures for filters attaining this effect, the following technology is known.
U.S. Pat. No. 3,843,235 discloses a structure of an apodization filter, in which a planar-concave lens made of light-absorbing glass and a convex-planar lens made of transparent glass are cemented together, and the optical power is set to substantially zero. Also disclosed are the optical characteristics when incorporating this apodization filter in an optical system. U.S. Pat. No. 3,843,235 also discloses a method for obtaining an apodization filter by applying a photosensitive resin on a transparent base and causing a coloring reaction in the light-sensitive resin through an optical mask, as well as a method for fabricating an apodization filter by a vacuum evaporation method on a transparent base. It is also mentioned that it is possible to provide a plurality of apodization filters having different transmission rate distributions, and to perform a light amount adjustment control that is optimal for each filter.
Japanese Patent Application Laid-Open No. H10 (1998)-268382 discloses a lens barrel to which an apodization filter can be mounted removably, and a camera in which aperture control is performed based on stored information corresponding to the type of the mounted filter.
Moreover, pages 74–77 of the April 1999 issue of "SHASHIN KOGYO" (Photo Industry), a monthly journal published by KK. SHASHIN KOGYO SHUPPANSHA, discloses a product application example of an apodization filter according to the technology disclosed in U.S. Pat. No. 3,843,235 and made by cementing together a planar-concave lens made of light-absorbing glass and a convex-planar lens made of transparent glass, and also discloses the transmission rate distribution characteristics of the apodization filter.
However, the following problems occur when the optical characteristics of the apodization filter are inappropriate:    (A) When a transmission rate at an outer periphery of a filter is too large, then an effect of smoothening the contours of blurred images is decreased.    (B) When a transmission rate at an outer periphery of a filter is too small, then a diameter of blurred images becomes small, and a three-dimensional impression and an impression of depth of an image are lost.    (C) When a shape of a transmission rate distribution is inappropriate, then the contours of blurred images become unnatural.    (D) When the average transmission rate of an overall effective filter portion is too small, then a transmitted light quantity is reduced, extending an exposure time and increasing an effect of camera shake.
Consequently, for the optical characteristics of an apodization filter, a shape of a transmission rate distribution is desired, at which an avoiding of the above-noted problems is well-balanced, but the conventional technology has the following problems:    (1) With a cemented glass filter as disclosed in U.S. Pat. No. 3,843,235 and on pages 74–77 of the April 1999 issue of "SHASHIN KOGYO," that is, with the apodization filter made by cementing together the planar-concave lens made of light-absorbing glass and the convex-planar lens made of transparent glass, a shape of the transmission rate distribution is limited substantially to the Gauss distribution (also referred to as a "normal distribution" in stochastic theory), and it is difficult to obtain characteristics that provide a well-balanced solution of the problems (A) to (D) described above.    (2) There is no specific numeric limitation to the transmission rate distribution disclosed in U.S. Pat. No. 3,843,235, and there is also no explicit disclosure relating optical characteristics that should be provided in order to solve the problems (A) to (D).    (3) Japanese Patent Application Laid-Open No. H10 (1998)-268382 discloses a mechanism by which different filters can be mounted selectively in accordance with the image-taking objectives, but there is no disclosure with regard to a method for optimizing the effect of smoothening the contours of blurred images, or the filter characteristics for this.
However, the above-mentioned related technologies have the following disadvantages:
(1) U.S. Pat. No. 3,843,235 does not disclose anything about driving of the apodization filter with respect to an aperture through which a light flux is transmitted. It is mentioned that a plurality of apodization filters with different effective diameters and transmission rate distributions may be provided and used as appropriate, but there are no specific explanations at all regarding a changing mechanism or a method for exposure control. On the other hand, in the related technology disclosed in Japanese Patent Application Laid-Open No. H10 (1998)-268382, the camera operator must change the apodization filters manually, so that its handling properties are poor and there is the risk of missing out on good photo opportunities.
(2) With the apodization filter disclosed in U.S. Pat. No. 3,843,235, which is made by cementing together the planar-concave lens made of light-absorbing glass and the convex-planar lens made of transparent glass, the degree of freedom for the design of the transmission rate distribution is low, and moreover there is the problem that the image-forming optical system tends to become large, because a thickness of the filter has to be made large. Moreover, an advancing/retracting mechanism for on-off switching of the apodization filter (meaning the control of the advancing and retracting with respect to the aperture) is necessary, so that there was a need for a structure with which the image-taking apparatus into which the filter is incorporated does not become large. It should be noted that U.S. Pat. No. 3,843,235 contains statements which seem to indicate that it is possible to make the apodization filter thinner and lighter, that is, to manufacture the apodization filter by forming the photosensitive resin or the vapor-deposited film on the transparent base, but there is no description of any specific manufacturing method.
(3) Not only the above-described apodization filter made by cementing together the planar-concave lens made of light-absorbing glass and the convex-planar lens made of transparent glass, but also apodization filters made by forming the photosensitive resin or the vapor-deposited film on the transparent base, which can be expected to be made thinner and lighter in the future, are expensive in view of their workability and the facilities that are required to manufacture them.
On the other hand, in image-taking apparatuses for capturing still pictures or moving images by using an image-pickup system such as a silver-halide film or an image-pickup means such as a CCD, there are deficiencies with regard to not only the light amount adjusting function but also the focus adjustment function when trying to obtain high-quality images. However, in the related technologies, there is no disclosure regarding a method for focus adjustment when using an apodization filter.
Moreover, the Minolta STF 135 mm F2.8 [T4.5] (trademark) is a product incorporating an apodization filter. This product is an exchangeable lens for a single lens reflex camera using 35 mm film. In a single lens reflex camera with exchangeable lens, the focus detection is ordinarily performed by using an autofocus (AF) mechanism of a phase difference detection method (more specifically a focus detection device). However, in focus defection devices employing phase difference detection method, when a transmission rate is changed continuously at the pupil position of the image-taking lens due to an apodization filter, then an illumination distribution of an object for focus detection which is projected onto an AF sensor is not uniform, so that focus detection discrepancies occur. Consequently, this produce was a lens for manual focusing only. (The foregoing has been summarized from "SHASHIN KOUGYOU", publ. by KK. SHASHIN KOUGYOU SHUPPANNSHA, April 1999 issue, p. 77.

Light amount adjusting apparatus, optical equipment, optical filter and image-taking apparatus


A wrench tool which has a head and connected handle formed as a lever. The head has a ratcheting mechanism and a distinctive shape different than the connected handle. The ratchet type wrench also has a gripping means with dimensions of length greater than width, and width greater than thickness. The gripping means encompasses a substantial portion, if not all of the handle, and at least a small portion of the ratchet head. In some preferred embodiments, the gripping means is formed with a "V" shaped or semi-circle shaped cut-out adapted to accommodate the shape of the ratchet head so that the gripping means does not obstruct the upper or lower surfaces of the ratchet head.

1. Field of the Invention
The present invention relates to tools, particularly hand tools and most particularly ratchet type wrenches. Ratchet wrenches are wrenches which have a head with a ratcheting mechanism to expedite the removal and installation of various fasteners. The present invention involves a compact, ergonomic ratchet wrench with a head at one end and a connected handle and lever at the other end. The present invention further involves a gripping means formed to encompass a substantial portion of the ratchet wrench handle and at least a small portion of the ratchet wrench head to improve user comfort and control.


An optical member is bonded to one surface of a holder. At least a pair of grooves are formed on the surface of the holder to leave an elevated portion which is smaller than the optical element in width. The optical member is bonded to the surface of the holder only at the elevated portion.

1. Field of the Invention
This invention relates to a structure for fixing an optical member to a holder, and more particularly to a structure for fixing an optical member to a holder by adhesive.
2. Description of the Related Art
As disclosed, for instance, in Japanese Unexamined Patent Publication No. 62(1987)-189783, there has been known a solid state laser in which a Nd-doped laser crystal is pumped with a semiconductor laser.
In such a solid state laser, an optical member such as an etalon is often provided in a resonator in order to make the oscillation mode a single longitudinal mode or to control polarizing direction.
A relatively small optical member such as an etalon is generally fixed to a holder which is larger than the optical member in size and is held in a predetermined position. FIG. 4 shows a conventional structure for fixing an optical member 2 to a holder 1. As shown in FIG. 4, in the conventional structure, the optical element 2 is bonded to the holder 1 substantially along the entire surface 2a facing the holder 1 except the portion opposed to an aperture 1a of the holder 1. The hatched portion in FIG. 4 represents the bonding area.
Though being simple, the conventional structure is disadvantageous in that the optical member can be deformed (warped) or broken when subjected to a temperature change due to difference in the linear expansion coefficient between the holder and the optical member. This problem is especially serious when the optical member is relatively small in thickness like the etalon or the optical member is apt to generate cleavage.


A method for fabricating porous UO2 sintered pellets to be fed into the electrolytic reduction process for the purpose of metallic nuclear fuel recovery is provided, which includes forming a powder containing U3O8 by oxidizing spent nuclear fuel containing uranium dioxide (UO2) (step 1), fabricating green pellets by compacting the powder formed in step 1 (step 2), fabricating UO2+x sintered pellets by sintering the porous U3O8 green pellets fabricated in step 2 at 1200 to 1600° C., in an atmospheric gas (step 3), and forming UO2 sintered pellets by cooling the UO2+x sintered pellets to room temperature, and reduction the same at 1000 to 1400° C., in a reducing atmosphere (step 4).

1. Field of the Invention
The present invention relates to a method for fabricating porous UO2 sintered pellets for an electrolytic reduction process for recovering metallic nuclear fuel, and porous UO2 sintered pellets fabricated in the same way, and more particularly, to a method for fabricating porous UO2 sintered pellets for an electrolytic reduction process by discontinuously performing atmospheric sintering and reduction to recover the metallic nuclear fuel.
2. Description of the Related Art
Spent nuclear fuel (UO2) from a light water reactor (LWR) generally includes fissile material (U) that is not consumed, and transuranic elements (TRU) that are generated from the burning. Along with this, UO2 also includes fission products. The pyroprocess is a recycle technology implemented to produce metallic nuclear fuel for use in a fast reactor, through pyrometallurgical and electrochemical processing from irradiated UO2 fuel in the LWR, thus providing advantages including good nuclear proliferation resistance. To recover the fissile material, the pyroprocessing mainly includes a pretreatment process to fabricate UO2 sintered pellets from U3O8 powder, and a follow-up process to convert the fabricated UO2 sintered pellets (i.e., ceramic nuclear fuel) into metallic nuclear fuel. The presence of fission products is desirably removed in the pretreatment process in consideration of the considerable influence on the follow-up process where the ceramic fuel is converted into metallic fuel. To be specific, the pretreatment process generally involves disassembly/cutting of a fuel rod, decladding, compacting, and sintering, and the follow-up process mainly involves electrolytic reduction, electro-refining, and electro-winning (see FIG. 1). The decladding in the pretreatment process relates to extracting spent UO2 sintered pellets from the disassembly/cut fuel rod, in which the UO2 sintered pellets within the fuel rod are generally converted into U3O8 in an air atmosphere at temperatures ranging between 350 and 700° C. The UO2 pellets are powdered owing to a volume expansion in accordance with the decreased density, and thus escapes from the fuel rod. As the phase changes from UO2 pellets to U3O8 powder from oxidation, gaseous volatile fission products including iodine (I) and bromine (Br) existing in the pellet are vaporized.
After the decladding, the U3O8 powder is compacted into the desired shapes and dimensions using a compacting machine such as a press. Then, by sintering at the appropriate temperature under desired atmospheric gas (e.g., oxidizing, inactive, nitrogen, and reducing gas), porous sintered pellets are fabricated, and are suitable for a volatilization of the fission products and are suitable for handling. Porous UO2 sintered pellets are advantageous, considering the fact that fission products are easily volatilized, and when the following electrolytic reduction is processed with UO2 rather than U3O8, the O/U ratio is decreased from 2.67 to 2.00, and owing to the decrease in the existing oxygen, the processing efficiency is increased greatly. Further, the process yield is increased, such that there is an advantage of increased productivity.
In a conventional technology, the U3O8 powder is compacted, and sintered for a predetermined time under an oxidizing, inactive, or nitrogen (N2) gas atmosphere, and thus UO2, sintered pellets (not porous UO2) are fabricated. If U3O8 green pellets are sintered for a predetermined time under a reducing atmosphere, it would be possible to fabricate porous UO2 sintered pellets. However, considering the fact that a low sintering temperature even under a reducing atmosphere will result in the fabrication of UO2+x (x=0.01-0.13) sintered pellets having a O/U ratio (i.e., ratio between oxygen elements to uranium elements) other than 2.00, it is necessary that the temperature be at least 1400° C. or greater to ensure that the porous UO2 sintered pellets are fabricated (see FIG. 1). Further, upon observation of the fracture surface of the sintered pellet fabricated under a reducing atmosphere, if the sintering temperature was relatively lower (i.e., lower than or equal to 1200° C.), there were relatively more inter-particle bonded aggregates of the powder, while at relatively higher sintering temperature (i.e., higher than or equal to 1400° C.), there were independently-existing powder particles, and inter-particle bonding was not observed (see FIG. 2). This indicates the fact that, above or equal to 1400° C., U3O8 is completely reduced into UO2, thereby removing inter-particle bonding.
Meanwhile, after U3O8 powder extracted from the fuel rod are compacted into a desired shape (cylindrical or cubical shape) and dimensions using a press, pores suitable for the volatilization of the fission products in the pellet are massively generated during sintering under an atmospheric gas (oxidizing, inactive, reducing, and nitrogen). Owing to the presence of the pores generated as explained above, the semi-volatile fission products existing in the pellet matrix are allowed to be more easily volatilized, and as the atmospheric gas facilitates the volatilization of the fission products, the fission products are basically not remained in the pellet matrix.
Korean Patent No. 10-0293482, incorporated herein by reference in its entirety, teaches a method for fabricating UO2 sintered pellets, which includes steps of fabricating green pellets by adding various kinds of sintering aids into oxidized U3O8 powder transformed from UO2 spent nuclear fuel, and fabricating UO2 sintered pellets by sintering the green pellets at temperatures above or equal to 1500° C. under a reducing atmosphere, thereby providing the advantage of providing UO2 sintered pellets with high sintered density. However, when the sintering under a high-temperature reducing atmosphere above or equal to 1400° is performed, the powder particles are not linked, but exist independently from each other in the fabricated sintered pellets. If this happens, the sintered pellets do not maintain their shape and collapse into fragments in the follow-up process, i.e., the electrolytic reduction. The fragments will then cause additional shortcomings such as inconvenient handling in the follow-up process. Further, the additives, which are added to enhance the sintered density of the sintered pellet, unnecessarily remain to affect the process when the metallic fuel is recovered by electrolytic reduction. Further, since such fuels including additives will also produce undesirable fission products in large amounts when recycled at a later stage, recycling can be inefficient.
In awareness of the above, the present inventors have been investigating a method for fabricating porous UO2 sintered pellets for an electrolytic reduction for the purpose of recovering metallic fuel from the spent nuclear fuel (UO2), and were able to develop a method for fabricating porous UO2 sintered pellets, which involves the steps of oxidizing the spent nuclear fuel (UO2) into U3O8, compacting the result into green pellets, sintering the green pellets to remove volatile and semi-volatile fission products, cooling the result at room temperature, and re-heating the cooled UO2+x sintered pellets for a reduction under a reducing atmosphere, and thus completed the present invention.


A moving image coding apparatus is provided. The moving image coding apparatus includes a processing unit having an information amount control processor determining a quantization parameter in such a manner that while a lead-in of the set of the pictures is set as a reference, upon a position of the inter-coded picture being after a predetermined position corresponds to a first position at a predetermined cycle shorter than the number of pictures included in the set of the pictures, the number of coding bits allocated to the inter-coded picture is a value obtained by adding a first predetermined amount to a predetermined reference value, and upon the position of the inter-coded picture being after the predetermined position and also at a second position different from the first position, the number of coding bits is a value obtained by subtracting a second predetermined amount from the reference value.

1. Field
The embodiments discussed herein are directed to a moving image coding apparatus and a moving image coding method for intra-coding particular images and inter-coding the other images.
2. Description of the Related Art
Moving image data generally has an extremely large data amount. In upon an apparatus dealing with the moving image data attempts to send the moving image data to another apparatus or store the moving image data in a storage apparatus, the apparatus compresses the moving image data. Coding methods employed for compressing the moving image data include an intra-coding method and an inter-coding method. The intra-coding method is a method of using only information included in one picture of a coding target and coding the relevant picture. This method is also referred to as intra-frame coding method or intra-picture coding method. On the other hand, the inter-coding method is a method of using information on a picture of a coding target and information of previous and subsequent pictures and coding the picture of the coding target According to the inter-coding method, the picture of the coding target is divided into a plurality of blocks. With respect to the respective blocks, from pictures obtained by decoding already coded previous and subsequent pictures, a most similar area is selected, and difference information between the respective blocks and the selected similar area is obtained. The difference information and motion vector information representing amounts at which the respective blocks are moved from the similar area are coded. For that reason, according to the inter-coding method, as redundant information can be removed, it is possible to achieve a compression efficiency higher than a compression efficiency based on the intra-coding method.
In contrast to this, according to the intra-coding method, in general, it is possible to reduce an error between the decoded picture obtained by decoding the coded data and the original picture. For that reason, an apparatus for reproducing the compressed coded moving image data can decode a picture with a high sharpness from the coded data according to the intra-coding method. On the other hand, according to the inter-coding method, as described above, only the difference information between the previous and subsequent pictures and the motion vector information are coded. If an error is included when any one of pictures is coded, the error propagates in other pictures after the relevant picture. In view of the above, in order to suppress the propagation of the coding error, a coding method of carrying out the intra-coding at a constant frequency is proposed. Such a coding method is, for example, adopted in standards such as ISO (International Organization for Standardization) Moving Picture Experts Group phase 2 (MPEG-2), MPEG-4, or ITU-T (International Telecommunication Union Telecommunication Standardization Sector) H.264/MPEG-4 Advanced Video Coding (H.264/MPEG-4 AVC). It should be noted that with regard to a plurality of continuous pictures repeated at this constant frequency, a coding method for the respective pictures is defined as Group Of Pictures (GOP). Also, hereinafter, among the pictures included in the GOP, a picture to be intra-coded is referred to as I-picture. Furthermore, a picture to be inter-coded by using the information on the temporally previous picture is referred to as P-picture. Furthermore, a picture to be inter-coded by using both the information on the temporally previous picture and the information on the temporally subsequent picture is referred to as B-picture. It should be noted that the picture is a frame or a field. The frame is one still image in the moving image data, and on the other hand, the field is a still image obtained by taking out only data in an odd-numbered row or data in an even-numbered row from the frame. A field having only the data in an odd-numbered row and a field having only the data in an even-numbered row are respectively referred to as top field and bottom field in the present specification.
A Constant Bit Rate (CBR) coding method is adopted in a system such as a digital broadcasting system having a high demand with respect to a real-time feature with regard to a moving image data distribution. This CBR coding method is a coding method of allocating a constant bit length to the coded moving image data for every unit of time. At this time, the I-picture located at the lead-in of the GOP functions as a reference for inter-coding other P-picture or B-picture. However, the compression efficiently of the intra-coding method is lower than the compression efficiently of the inter-coding method. In order to reduce the coding error of the I-picture as much as possible, it is necessary to allocate the I-picture with a larger information amount, that is, a larger number of coding bits. If the I-picture is allocated with many coding bits, as the number of bits per unit of time is decided in the CBR coding method, the number of coding bits which can be allocated to the P-picture and the B-picture in the GOP is smaller.
The system having the high demand with respect to the real-time feature suppresses a delay due to the coding of the moving image data, and the B-picture requiring the information on the previous and subsequent picture for the coding is not used in many cases. If the B-picture having the highest compression efficiency is not included in the GOP, the number of coding bits allocated to the P-picture is inevitably insufficient. As a result, the sharpness of the P-picture decoded from the moving image data which is coded through this CBR coding method is decreased. On the other hand, as described above, the I-picture is allocated with the sufficient number of coding bits, and thus the decoded I-picture has a high sharpness. Due to this difference in the sharpness between the P-picture and the I-picture, a subjective image quality of a viewer with respect to the decoded moving image data is decreased.
With respect to such a problem, it is reported in the following paper that if a high image quality picture and a low image quality picture are alternately arranged in the moving image data, the subjective image quality of the viewer with respect to the moving image data is satisfactory.
FUKINUKI, "Sharp/Blurred Sampled Motion Pictures and Its Application to Picture Coding"
—Extension of the Signal Processing of Motion Visual Perception—
PCSJ2007/IMPS2007, No. P 3-03 (October 2007)
However, in the GOP dealing with a scene with a motion, a picture temporally closer to the picture of interest has more similarity. Therefore, according to the inter-coding method, as a reference picture functioning as a reference for the inter-coding, by using the temporally closest picture, the coding error can be reduced. However, as described above, upon the moving image data is inter-coded so that the high quality pictures and the low quality pictures are alternately arranged from the lead-in of the GOP, the picture temporally closest to the picture of interest may have a substantially degraded image quality due to the coding. That is, it is conceivable that as the coding is carried out Based on the degraded image, the coding errors may be accumulated. The P-picture included in a second half of the GOP has the prominent image degradation due to the accumulation of the coding errors, and therefore a difference in image quality between the P-picture included in the second half of the GOP and the image quality of the I-picture immediately after the P-picture is extremely large. In the decoded moving image data, flicker noise generated per unit of GOP is conspicuous.

Moving image coding apparatus and moving image coding method


An electrical connector assembly (100) mounted on a printed circuit board (PCB) includes an insulative housing (1) defining a pair of stacked receiving cavities (15, 16) for receiving a first and a second connector components (2, 3) therein, a holder (4) attached to the insulative housing and a metal shield enclosing the insulative housing. The holder (4) is fixed to a rear wall (14) of the insulative housing (1) and includes a vertical mating portion (41) and a pair of top and bottom portions (42, 43) extending backwardly from the mating portion. The top and bottom portions (42, 43) are parallel to each other wherein the top portion (42) is shorter than the bottom portion (43). An area of the top portion is smaller than that of the bottom portion.

1. Field of the Invention
This invention generally relates to a stacked electrical connector assembly, and more particularly to a stacked electrical connector assembly mounted on a printed circuit board (PCB) to mate with corresponding plugs.
2. Description of the Prior Art
A computer is required to provide connectors mounted on a PCB at input/output ports to mate with corresponding connectors of peripheral devices for signal transmission therebetween. In order to sufficiently utilize limited area of the PCB, the electrical connectors are usually arranged in a stacked manner. U.S. Pat. No. 6,540,563 B1 discloses such an electrical connector assembly comprising an insulative housing, a pair of upper and lower connectors vertically stacked in the insulative housing, a spacer connected to the insulative housing, and a board mounting surface on a lower portion thereof. The spacer is attached to a rear face of the insulative housing to form a combination in cubic-shaped configuration. A top and a bottom faces of the combination are of the same length and the same area so that the bottom face lacks of necessary retaining force. Besides, the upper connector is so high relative to the mounting surface that the electrical connector assembly is easy to incline when the corresponding connectors are inserted into or pulled out therefrom. As a result, the electrical connection between the electrical connector assembly and the PCB is unreliable, and the quality of signal transmission therebetween may be adversely affected.
Hence, it is desired to have an electrical connector assembly solving the problem above.

Stacked electrical connector assembly with stable mating characteristic