Abstract: Provided are a biodegradable aliphatic-aromatic polyester copolymer having excellent hydrolysis resistance and high viscosity which has a carboxyl end group (CEG) content of 15 mg KOH/g or less, a ratio (Mz/Mn) of a z-average molecular weight (Mz) to a number average molecular weight (Mn) of 3 to 15, and a melt index (MI) of 5 g/10 min or less as measured under conditions of a temperature of 190° C. and a load of 2.16 kg in accordance with ASTM D 1238. A method of preparing a biodegradable aliphatic-aromatic polyester copolymer is provided, including adding a chain extender and an anti-hydrolysis agent to an aliphatic-aromatic polyester pre-copolymer over time, whereby a significant viscosity rise and improvement of hydrolysis resistance may be implemented simultaneously.

Abstract: Provided are a biodegradable aliphatic-aromatic polyester copolymer having excellent hydrolysis resistance and high viscosity which has a carboxyl end group (CEG) content of 15 mg KOH/g or less, a ratio (Mz/Mn) of a z-average molecular weight (Mz) to a number average molecular weight (Mn) of 3 to 15, and a melt index (MI) of 5 g/10 min or less as measured under conditions of a temperature of 190° C. and a load of 2.16 kg in accordance with ASTM D 1238. A method of preparing a biodegradable aliphatic-aromatic polyester copolymer is provided, including adding a chain extender and an anti-hydrolysis agent to an aliphatic-aromatic polyester pre-copolymer over time, whereby a significant viscosity rise and improvement of hydrolysis resistance may be implemented simultaneously.

Abstract: A display device includes a first substrate. A transistor is disposed on the first substrate. A light-emitting element is connected to the transistor. An insulating layer is disposed between the transistor and the light-emitting element. A second substrate at least partially overlaps the first substrate. A color conversion layer is disposed on the second substrate. The insulating layer includes a first insulating layer and a second insulating layer. A distance between the first insulating layer and the first substrate is less than a distance between the second insulating layer and the first substrate. The first insulating layer includes a light blocking material.

Abstract: A method of preparing a positive electrode active material having a high ratio of charge and discharge capacity at a charge end voltage of 4.1 V to 4.175 V to charge and discharge capacity at a charge end voltage of 4.2 V to 4.275 V and having an excellent initial charge and discharge capacity is provided.

Abstract: Disclosed is a method for pre-detecting a defective porous polymer substrate for a separator, including selecting a porous polymer substrate having a plurality of pores; observing the selected porous polymer substrate with a scanning electron microscope (SEM) to obtain an image of the porous polymer substrate; quantifying the average value of pore distribution index (PDI); correcting the quantified average value of pore distribution index to obtain the corrected average value of pore distribution index; determining whether or not the corrected average value of pore distribution index is 60 a.u. (arbitrary unit) or less; and classifying the porous polymer substrate as a good product, when the corrected average value of pore distribution index is determined to be 60 a.u. or less, and classifying the porous polymer substrate as a defective product, when the corrected average value of pore distribution index is determined to be larger than 60 a.u.

Abstract: A high power waveguide valve capable of selectively transmitting or sealing the high power without causing its breakdown during a high power operation is disclosed. The inventive high power waveguide valve includes a vacuum chamber, a U-shaped waveguide being provided in the vacuum chamber, a first linear motion driver for vertically sliding the U-shaped waveguide, a dual H-corners assembly connected with the U-shaped waveguide, a sealing plate for selectively sealing the radio frequency between the U-shaped waveguide and the dual H-corners assembly, and a second linear motion driver for horizontally sliding the sealing plate.