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The two rows of holes (labelled #3) are test points used during the manufacture of this USB memory key. Testpoints on a printed circuit board (labelled E34, E35, E36, …) next to teardrop vias. A test point is a location within an electronic circuit that is used to either monitor the state of the circuitry or to inject test signals. [1]
Natural tantalum (73 Ta) consists of two stable isotopes: 181 Ta (99.988%) and 180m Ta (0.012%). There are also 35 known artificial radioisotopes, the longest-lived of which are 179 Ta with a half-life of 1.82 years, 182 Ta with a half-life of 114.43 days, 183 Ta with a half-life of 5.1 days, and 177 Ta with a half-life of 56.56 hours.
One of the key features of the TAs is the autoregulation. The antitoxin and toxin protein complex bind to the operator that is present upstream of the TA genes. This results in repression of the TA operon. The key to the regulation are (i) the differential translation of the TA proteins and (ii) differential proteolysis of the TA proteins.
Tantalum is a chemical element; it has symbol Ta and atomic number 73. Previously known as tantalium , [ citation needed ] it is named after Tantalus , a figure in Greek mythology. [ 11 ] Tantalum is a very hard, ductile , lustrous , blue-gray transition metal that is highly corrosion-resistant.
The melting points of tantalum carbides was previously estimated to be about 3,880 °C (4,150 K; 7,020 °F) depending on the purity and measurement conditions; this value is among the highest for binary compounds. [6] [7] And only tantalum hafnium carbide was estimated to have a higher melting point of 3,942 °C (4,215 K; 7,128 °F). [8]
Tantalum pentachloride, Ta 2 Cl 10, provides a convenient starting point. To avoid the generation of mixed chloride-ethoxide species, a base such as ammonia is usually added to trap liberated HCl: [8] 10 EtOH + Ta 2 Cl 10 + 10 NH 3 → Ta 2 (OEt) 10 + 10 NH 4 Cl. Salt metathesis using an alkali metal alkoxide can be used as well: [8]
The tantalum–tungsten alloys are characterized by their high melting point and the tension resistance. The properties of the final alloy are a combination of properties from the two elements: tungsten, the element with the highest melting point in the periodic table, and tantalum which has high corrosion resistance. [1] [2]
Tantalum nitride (TaN) is a chemical compound, a nitride of tantalum.There are multiple phases of compounds, stoichimetrically from Ta 2 N to Ta 3 N 5, including TaN.. As a thin film TaN find use as a diffusion barrier and insulating layer between copper interconnects in the back end of line of computer chips.