Abstract: Disclosed herein are related to systems and methods for a successive approximation analog to digital converter (SAR ADC). In one aspect, the SAR ADC includes a calibration circuit configured to receive some or all of the plurality of bits corresponding to the input voltage and accumulates or averages at least some of the bits corresponding to the input voltage. The calibration circuit is configured to provide a first offset signal to control a first offset associated with a first comparator, a second offset signal to control a second offset associated with a second comparator, or reduce an offset difference associated with the first offset and the second offset.

Abstract: An apparatus may include a first clock generator configured to receive an input clock signal, and generate two or more first-level clock signals of a track-and-hold circuit, a phase interpolator configured to generate an interpolated clock signals, wherein the interpolated clock signal is based on the two or more first-level clock signals, and a second clock generator configured to generate two or more second-level clock signals based on the interpolated clock signal, wherein the phase of the two or more second-level clock signals relative to the phase of a respective first-level clock signal is determined, at least in part, by the phase of the interpolated clock signal.

Abstract: The invention relates to an asymmetric hydrogenation method for ketone compounds, comprising the step of: under hydrogen atmosphere, in the presence of an in situ catalyst derived from a chiral ligand and a ruthenium salt, adding a ketone compound and a base into a second solvent to carry out an asymmetric hydrogenation for the ketone compound. The invention can obtain a conversion of 100% and a highest asymmetric inducement effect of 99.7% for the ketone compound. The invention has the advantages including simple procedure, high conversion and selectivity, good atom economy and good prospect of industrial application.

Abstract: The invention affords C2-symmetrical ruthenocene diphosphine ligands with surface chirality and their manufacture. The present invention uses (S)-(S)-1,1?-2(diphenylphosphino)-2,2?-2[(S)-4-isopropyloxazolinyl] ruthenocene as raw material and the product is prepared through two or three steps of reaction. At the action of trifluoroacetic acid, (S)-(S)-1,1?-2(diphenylphosphino)-2,2?-2[(S)-4-isopropyloxazolinyl] ruthenocene first removes oxazoline and gets ester amides compound which then carries out ester exchange or reduction alkylation and gets the product of ruthenocene diphosphine ligand with surface chirality. The ligands prepared with the structure as follows from the invention can be used in all kinds of metallic catalysis asymmetric reaction and has good reaction activity and stereoselectivity, wherein R is methyl or ethyl, R1 is linear or branched alkyl, cycloalkyl, alkoxy, aryl, aralkyl and alkyl amino.

Abstract: The invention relates to an asymmetric hydrogenation method for ketone compounds, comprising the step of: under hydrogen atmosphere, in the presence of an in situ catalyst derived from a chiral ligand and a ruthenium salt, adding a ketone compound and a base into a second solvent to carry out an asymmetric hydrogenation for the ketone compound. The invention can obtain a conversion of 100% and a highest asymmetric inducement effect of 99.7% for the ketone compound. The invention has the advantages including simple procedure, high conversion and selectivity, good atom economy and good prospect of industrial application.

Abstract: The invention affords C2-symmetrical ruthenocene diphosphine ligands with surface chirality and their manufacture. The present invention uses (S)—(S)-1,1?-2(diphenylphosphino)-2,2?-2[(S)-4-isopropyloxazolinyl]ruthenocene as raw material and the product is prepared through two or three steps of reaction. At the action of trifluoroacetic acid, (S)—(S)-1,1?-2(diphenylphosphino)-2,2?-2[(S)-4-isopropyloxazolinyl]ruthenocene first removes oxazoline and gets ester amides compound which then carries out ester exchange or reduction alkylation and gets the product of ruthenocene diphosphine ligand with surface chirality. The ligands prepared with the structure as follows from the invention can be used in all kinds of metallic catalysis asymmetric reaction and has good reaction activity and stereoselectivity, wherein R is methyl or ethyl, R1 is linear or branched alkyl, cycloalkyl, alkoxy, aryl, aralkyl and alkyl amino.