摘要:
Catalyst systems for the copolymerization of carbon monoxide and α-olefinically unsaturated compounds contain, as essential components, a) a metal complex of the formula (I) where R1 to R4 are each linear or branched C2- to C28-alkyl, C3- to C14-cycloalkyl or alkylaryl where the alkyl moiety is of 1 to 28 carbon atoms and the aryl moiety is of 6 to 15 carbon atoms, each of which is substituted by at least one polar protic or ionic functional group based on elements of groups IVA to VIA of the Periodic Table of Elements, and b) if required, one or more Lewis or protic acids or a mixture of Lewis and protic acids.
摘要:
Water-soluble transition metal complexes of the formula (I) where R1 to R4 are linear or branched C2- to C28-alkyl, C3- to C14-cycloalkyl or alkylaryl where the alkyl moiety is of 1 to 28 carbon atoms and the aryl moiety is of 6 to 15 carbon atoms, each of which is substituted by at least one polar protic or ionic functional group based on nonmetallic elements of groups IVA to VIA of the Periodic Table of Elements.
摘要:
Transition metal complexes having bulky ligand systems and the formula (I) where R2, R4 are C4-C16-heteroaryl or C6-C16-aryl bearing C4-C16-heteroaryl or C6-C16-aryl substituents in the two vicinal positions relative to the point of linkage to Na or Nb and M is a metal of group VIIIB of the Periodic Table of the Elements, are described.
摘要:
Process for preparing an aqueous polymer dispersion by polymerization of at least one olefinically unsaturated compound in an aqueous medium in the presence of at least one dispersant and a solid polymerization catalyst.
摘要:
Process for preparing an aqueous polymer dispersion by polymerization of at least one olefinically unsaturated compound in an aqueous medium in the presence of at least one dispersant and a solid polymerization catalyst.
摘要:
Disclosed is a method for producing an aqueous polymer dispersion, according to which unsaturated monomers are first polymerized by means of suitable catalysts, whereupon the obtained polymers that are swelled with all or some of the remaining unreacted monomers are added to surface-active substances and water in a last step in which the obtained polymers are not entirely separated from the remaining monomers.
摘要:
Linear, alternating .alpha.-olefin-CO copolymers are obtainable by polymerization of a monomer mixture comprisinga) carbon monoxide,b) 1-alkenes which are functionalized by a covalently bonded crown ether unit or cryptand unit A containing at least 5 heteroatoms selected from the group consisting of nitrogen, oxygen, sulfur and/or selenium in the polyheteroatom framework, and, if desired,c) C.sub.2 -C.sub.24 -1-alkenes.
摘要:
A method is disclosed of controlling a switched mode converter comprising a switch and for providing power to device having a load, comprising: in response to the load exceeding a first threshold, operating in a first mode, being a CCM; in response to the load exceeding a second threshold and not exceeding the first threshold, operating in second mode, being a BCM without valley skipping wherein the switching frequency increases with decreasing load; in response to the load exceeding a third threshold and not exceeding the second threshold, operating in a third mode, being a BCM with valley skipping, wherein the switching frequency depends on the load and the number of valleys skipped and is between a fixed upper and a lower switching frequency limit; and in response to the load not exceeding the third threshold, operating in a fourth mode, being a BCM with valley skipping, wherein the switching frequency depends on at least the load, and is between an upper and a lower switching frequency limit wherein the upper switching frequency limit decreases with decreasing load. A switched mode converter controlled by such a method is also disclosed.
摘要:
A power conversion controller for controlling the operation of a switch in a power conversion circuit, wherein the power conversion controller is configured to operate the switch according to: a variable frequency mode of operation for switching frequencies greater than a minimum threshold value; and a fixed frequency mode of operation at a switching frequency equal to the minimum threshold value.
摘要:
Consistent with an example embodiment, a circuit comprises a power factor correction stage having a DC input, a ground input, a DC output and a ground output. The circuit further includes a capacitor; a diode; and a discharge circuit. A first terminal of the diode is connected to an input of the power factor correction stage, a second terminal of the diode is connected to the first plate of the capacitor; and the second plate of the capacitor is connected to the other input of the PFC stage. The discharge circuit is connected to the capacitor and is configured to discharge the capacitor such that it contributes to the output of the PFC stage when the level of a signal at the input of the PFC stage falls below a threshold value.