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4000 Series
The 4000 series is a CMOS logic family of integrated circuits (ICs) first introduced in 1968 by RCA. It had a supply voltage range of 5V to 20V, which is much wider than any contemporary logic family. Almost all IC manufacturers active during this initial era fabricated models for this series. Its naming convention is still in use today. History The 4000 series was introduced as the ''CD4000 COS/MOS'' series in 1968 by RCA as a lower power and more versatile alternative to the 7400 series of transistor-transistor logic (TTL) chips. The logic functions were implemented with the newly introduced Complementary Metal–Oxide–Semiconductor (CMOS) technology. While initially marketed with "COS/MOS" labeling by RCA (which stood for Complementary Symmetry Metal-Oxide Semiconductor), the shorter ''CMOS'' terminology emerged as the industry preference to refer to the technology. The first chips in the series were designed by a group led by Albert Medwin. Wide adoption was initially hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cd4007
In molecular biology, CD4 (cluster of differentiation 4) is a glycoprotein that serves as a co-receptor for the T-cell receptor (TCR). CD4 is found on the surface of immune cells such as T helper cells, monocytes, macrophages, and dendritic cells. It was discovered in the late 1970s and was originally known as leu-3 and T4 (after the OKT4 Monoclonal antibodies, monoclonal antibody that reacted with it) before being named CD4 in 1984. In humans, the CD4 protein is encoded by the ''CD4'' gene. T helper cell, CD4+ T helper cells are leukocytes, white blood cells that are an essential part of the human immune system. They are often referred to as CD4 cells, T-helper cells or T4 cells. They are called helper cells because one of their main roles is to send signals to other types of immune cells, including CD8 cytotoxic t cell, killer cells, which then destroy the infectious particle. If CD4 cells become depleted, for example in untreated HIV infection, or following immune suppressio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
