Abstract: Provided are a structure and fabricating method of a new inverter for controlling a threshold voltage of each location when an inverter circuit is manufactured using an organic semiconductor on a plastic substrate. In general, p-type organic semiconductor is stable. Accordingly, when the inverter is formed of only the p-type semiconductor, a D-inverter composed of a depletion load and an enhancement driver has large gains, wide swing width and low power consumption, which is more preferable than an E-inverter composed of an enhancement load and an enhancement driver. However, it is impossible to form a depletion transistor and an enhancement transistor on the same substrate while controlling them by locations.

Abstract: Provided is an inverter having a new structure capable of easily controlling a threshold voltage according to position in fabricating an inverter circuit on a plastic substrate using an organic semiconductor. A driver transistor is formed with a dual-gate structure and a positive bias voltage is applied to the top gate of the driver transistor so that a body effect appears in the organic semiconductor. Accordingly, the threshold voltage is shifted to a negative zone due to positive potential applied to the top gate of the driver transistor so that the driver transistor acts as an enhancement type transistor. A dual-gate organic structure may be applied to a load transistor rather than the driver transistor, or a p-type dual-gate organic transistor structure may be applied to both the driver transistor and the load transistor.

Abstract: Disclosed is a method for optically resolving a racemic &agr;-substituted heterocyclic carboxylic acid (&agr;-HCCA) by taking advantage of enantioselectivity of enzymes. &agr;-HCCA is reacted with alcohol to give a racemic &agr;-HCCA ester, which is then reacted with an enzyme with enantioselectivity, whereby either R-form or S-form of the racemate is hydrolyzed. Extraction with an organic solvent can obtain enantiomers of the &agr;-HCCA ester. The extracted enantiomeric &agr;-HCCA ester is converted to enantiomeric &agr;-HCCA by catalytic hydrogenation in an organic solution or by enzymatic hydrolysis in an aqueous solution. Thus, a racemic mixture of &agr;-HCCA can be optically resolved with high optical purity at high yields as well as at low cost.

Abstract: Disclosed is a method for preparing an R- or S-forms of &agr;-substituted heterocyclic carboxylic acid (&agr;-HCCA) and a counter enantiomeric form of &agr;-substituted heterocyclic carboxylic acid ester thereto by use of an enzyme. A racemic &agr;-HCCA is reacted with alcohol to give a racemic &agr;-HCCA ester, which is then brought into contact with an enzyme with enantioselectivity, whereby either R-form or S-form of the racemate is hydrolyzed. Extraction with an organic solvent can obtain enantiomers of the &agr;-HCCA ester. Thus, a certain enantiomeric form of &agr;-HCCA and a counter enantiomeric form of &agr;-HCCA ester thereto, respectively can be prepared with high optical purity at high yields as well as at low cost.

Abstract: Disclosed is a method for optically resolving a racemic &agr;-substituted heterocyclic carboxylic acid (&agr;-HCCA) by taking advantage of enantioselectivity of enzymes. &agr;-HCCA is reacted with alcohol to give a racemic &agr;-HCCA ester, which is then reacted with an enzyme with enantioselectivity, whereby either R-form or S-form of the racemate is hydrolyzed. Extraction with an organic solvent can obtain enantiomers of the &agr;-HCCA ester. The extracted enantiomeric &agr;-HCCA ester is converted to enantiomeric &agr;-HCCA by catalytic hydrogenation in an organic solution or by enzymatic hydrolysis in an aqueous solution. Thus, a racemic mixture of &agr;-HCCA can be optically resolved with high optical purity at high yields as well as at low cost.

Abstract: Disclosed is a method for preparing an R- or S-forms of &agr;-substituted heterocyclic carboxylic acid (&agr;-HCCA) and a counter enantiomeric form of &agr;-substituted heterocyclic carboxylic acid ester thereto by use of an enzyme. A racemic &agr;-HCCA is reacted with alcohol to give a racemic &agr;-HCCA ester, which is then brought into contact with an enzyme with enantioselectivity, whereby either R-form or S-form of the racemate is hydrolyzed. Extraction with an organic solvent can obtain enantiomers of the &agr;-HCCA ester. Thus, a certain enantiomeric form of &agr;-HCCA and a counter enantiomeric form of &agr;-HCCA ester thereto, respectively can be prepared with high optical purity at high yields as well as at low cost.

Abstract: The present invention relates to polyether amino acid ester compounds, preparation method and their use as hydrocarbon fuel additives.