Republic Pictures Corporation was an American motion picture production-distribution corporation in operation from 1935 to 1967, based in Los Angeles, California. It had studio facilities in a movie ranch in Encino, it was best known for specializing in serials and B films emphasizing mystery and action. Republic was notable for developing the careers of John Wayne, Gene Autry and Roy Rogers, it was responsible for the financing and distribution of several films directed by John Ford during the 1940s and early 1950s and one Shakespeare film, directed by Orson Welles. Under Herbert J. Yates, Republic was considered a mini-major film studio. Created in 1935 by Herbert J. Yates, a longtime investor in film and owner of the film processing laboratory Consolidated Film Industries, Republic was formed by Yates' acquisition of six smaller independent Poverty Row studios. In the depths of the Great Depression, Yates' laboratory was no longer serving the major studios, which had developed their own in-house laboratories for purposes of both economy and control, while the small, independent producers were going under in the face of increased competition from the majors combined with the general impact of the depressed economy.
In 1935 he thus decided to create a studio of his own to insure Consolidated's stability. Six surviving small companies were all in debt to Yates' lab, he prevailed upon these studios to merge under his leadership or else face foreclosure on their outstanding lab bills. Yates' new company, Republic Pictures Corporation, was presented to their producer-owners as a collaborative enterprise focused on low-budget product; the largest of Republic's components was Monogram Pictures, run by producers Trem Carr and W. Ray Johnston, which specialized in "B" films and operated a nationwide distribution system; the most technologically advanced of the studios that now comprised Republic was Nat Levine's Mascot Pictures Corporation, making serials exclusively since the mid-'20s and had a first-class production facility, the former Mack Sennett lot in Studio City. Mascot had just discovered Gene Autry and signed him to a contract as a singing cowboy star. Larry Darmour's Majestic Pictures had developed an exhibitor following with big-name stars and rented sets giving his humble productions a polished look.
Republic took its original "Liberty Bell" logo from M. H. Hoffman's Liberty Pictures as well as Hoffman's talents as a low-budet film producer. Chesterfield Pictures and Invincible Pictures, two sister companies under the same ownership, were skilled in producing low-budget melodramas and mysteries. Acquiring and integrating these six companies enabled Republic to begin life with an experienced production staff, a company of veteran B-film supporting players and at least one promising star, a complete distribution system and a functioning and modern studio. In exchange for merging, the principals were promised independence in their productions under the Republic aegis, higher budgets with which to improve the quality of the films. After he had learned the basics of film production and distribution from his partners, Yates began asserting more and more authority over their film departments, dissension arose in the ranks. Carr and Johnston left and reactivated Monogram Pictures in 1937. Meanwhile, Yates installed a staff of new, "associate" producers.
Freed of partners, Yates presided over what was now his film studio and acquiring senior production and management staff who served him as employees, not experienced peers with independent ideas and agendas. Republic acquired Brunswick Records to record its singing cowboys Gene Autry and Roy Rogers and hired Cy Feuer as head of its music department. At the 1958 annual meeting, Yates announced the end of motion picture production. In its early years Republic was itself sometimes labelled a "Poverty Row" company, as its primary products were B movies and serials. Republic, showed more interest in — and provided larger budgets to — these films than many of the larger studios were doing, more than other independents were able to; the heart of the company was its westerns, its many western-film leads — among them John Wayne, Gene Autry, Rex Allen and Roy Rogers — became recognizable stars at Republic. However, by the mid-'40s Yates was producing better-quality pictures, mounting big-budget fare like The Quiet Man, Sands of Iwo Jima, Johnny Guitar and The Maverick Queen.
Another distinguishing aspect of Republic Pictures was Yates' avoidance of any controversial subject matter, adhering to the Breen Office, in contrast to the other "Poverty Row" studios, which dodged the Production Code. In 1946 Republic incorporated animation into its Gene Autry feature film Sioux City Sue, it turned out well enough for the studio to dabble in animated cartoons. After leaving Warner Bros. in 1946, Bob Clampett approached Republic and wound up directing a single cartoon, It's a Grand Old Nag, featuring the equine character Charlie Horse. Republic management, had second thoughts owing to dwindling profits, and
Pliomera is a genus of trilobites that lived during the Middle Ordovician on the paleocontinent Baltica, now Norway, Sweden and the Russian Federation, in Argentina. It can be recognized for its pentagonal glabella widest between the frontal corners, with an inverted V-shaped occipital ring. In front of the occipital furrow that crosses the entire glabella, two pairs of dead-ending furrows create three side lobes left and right; the front of the glabella has three dead-ending furrows, a short one on the midline and left and right a longer one, directed inward and backward. The eyes are not connected to the glabella by an eye ridge; the thorax and pygidium are regularly divided into up to 23 rather narrow segments, without a furrow within each of the pleurae. The pleurae are wider than the axis; the pygidium ends in downward pointing toothlike spines. Species assigned to Pliomera are: P. insangensis = Encrinurella insangensis P. insolita = Kanoshia insolita P. linnarssoni = Pliomerops linnarssoni P. martelli = Pliomerina martelli P. sulcifrons = Pliomerina sulcifrons P. brevicapitata occurs in the Middle Ordovician of the Russian Federation.
P. fischeri is known from the Middle Ordovician of the Russian Federation. Pliomera has a pentagonal glabella, widest between the frontal corners, has an inverted V-shaped occipital ring. In front of the occipital furrow that crosses the entire glabella, two pairs of dead-ending furrows, create three side lobes left and right; the front of the glabella has three dead-ending furrows, a short one on the midline and left and right a longer one, directed inward and backward. A efficient fastening device is unique in Pliomera, it consists of a row of 7 to 9 downward directed denticles along the front of the glabella, which interlocked with corresponding teeth on the pygidium, when the animal protected itself by enrolling. The eyes are small and raised above the cheeks but not connected to the glabella by an eye ridge; the facial sutures in genus Pliomera itself are gonatoparian, while in the genus Placoparia these are opisthoparian, this is unlike all other pliomerids where facial sutures are proparian.
The thorax may have between 18 segments. The pygidium has small termination; the corresponding pleural segments are well defined and end in tooth-like points, the last pair of, embracing the small terminal axial segment
An insulated-gate bipolar transistor is a three-terminal power semiconductor device used as an electronic switch which, as it was developed, came to combine high efficiency and fast switching. It consists of four alternating layers that are controlled by a metal–oxide–semiconductor gate structure without regenerative action. Although the structure of the IGBT is topologically the same as a thyristor with a'MOS' gate, the thyristor action is suppressed and only the transistor action is permitted in the entire device operation range, it is used in switching power supplies in high power applications: variable-frequency drives, electric cars, variable speed refrigerators, lamp ballasts, air-conditioners. Since it is designed to turn on and off the IGBT can synthesize complex waveforms with pulse-width modulation and low-pass filters, so it is used in switching amplifiers in sound systems and industrial control systems. In switching applications modern devices feature pulse repetition rates well into the ultrasonic range—frequencies which are at least ten times the highest audio frequency handled by the device when used as an analog audio amplifier.
As of 2010, the IGBT is the second most used power transistor, after the power MOSFET. An IGBT cell is constructed to a n-channel vertical-construction power MOSFET, except the n+ drain is replaced with a p+ collector layer, thus forming a vertical PNP bipolar junction transistor; this additional p+ region creates a cascade connection of a PNP bipolar junction transistor with the surface n-channel MOSFET. The metal–oxide–semiconductor field-effect transistor was invented by Mohamed M. Atalla and Dawon Kahng at Bell Labs in 1959; the basic IGBT mode of operation, where a pnp transistor is driven by a MOSFET, was first proposed by K. Yamagami and Y. Akagiri of Mitsubishi Electric in the Japanese patent S47-21739, filed in 1968. Following the commercialization of power MOSFETs in the 1970s, B. Jayant Baliga submitted a patent disclosure at General Electric in 1977 describing a power semiconductor device with the IGBT mode of operation, including the MOS gating of thyristors, a four-layer VMOS structure, the use of MOS-gated structures to control a four-layer semiconductor device.
He began fabricating the IGBT device with the assistance of Margaret Lazeri at GE in 1978 and completed the project in 1979. The results of the experiments were reported in 1979; the device structure was referred to as a "V-groove MOSFET device with the drain region replaced by a p-type anode region" in this paper and subsequently as "the insulated-gate rectifier", the insulated-gate transistor, the conductivity-modulated field-effect transistor and "bipolar-mode MOSFET". An MOS-controlled triac device was reported by B. W. Scharf and J. D. Plummer with their lateral four-layer device in 1978. Plummer filed a patent application for this mode of operation in the four-layer device in 1978. USP No. 4199774 was issued in 1980, B1 Re33209 was reissued in 1996. The IGBT mode of operation in the four-layer device switched to thyristor operation if the collector current exceeded the latch-up current, known as "holding current" in the well known theory of the thyristor; the development of IGBT was characterized by the efforts to suppress the thyristor operation or the latch-up in the four-layer device because the latch-up caused the fatal device failure.
The technology of IGBT had, been established when the complete suppression of the latch-up of the parasitic thyristor was achieved as described in the following. Hans W. Becke and Carl F. Wheatley developed a similar device, for which they filed a patent application in 1980, which they referred to as "power MOSFET with an anode region"; the patent claimed that "no thyristor action occurs under any device operating conditions". The device had an overall similar structure to Baliga's earlier IGBT device reported in 1979, as well as a similar title. A. Nakagawa et. al. invented the device design concept of non-latch-up IGBTs in 1984. The invention is characterized by the device design setting the device saturation current below the latch-up current, which triggers the parasitic thyristor; this invention realized complete suppression of the parasitic thyristor action, for the first time, because the maximal collector current was limited by the saturation current and never exceeded the latch-up current.
After the invention of the device design concept of non-latch-up IGBTs, IGBTs evolved and the design of non-latch-up IGBTs became a de facto standard and the patent of non-latch-up IGBTs became the basic IGBT patent of actual devices. In the early development stage of IGBT, all the researchers tried to increase the latch-up current itself in order to suppress the latch-up of the parasitic thyristor. However, all these efforts failed. Successful suppression of the latch-up was made possible by limiting the maximal collector current, which IGBT could conduct, below the latch-up current by controlling/reducing the saturation current of the inherent MOSFET; this was the concept of non-latch-up IGBT. “Becke’s device” was made possible by the non-latch-up IGBT. The IGBT is characterized by its ability to handle a high voltage and a large current; the product of the voltage and the current density that the IGBT can handle reached more than 5×105 W/cm2, which far exceeded the value, 2×105 W/cm2, of existing power devices such as bipolar transistors and power MOSFETs.
This is a consequence of the large safe operating area of the IGBT. The IGBT is the most rugged and the strongest power device that developed, providing u