Abstract: The present disclosure provides a method for preparing a vinyl chloride-based polymer, the method including a step of injecting an ionizable normal salt and polymerizing a vinyl chloride monomer in the presence of one or more emulsifiers and a polymerization initiator, wherein the ionizable normal salt includes a carbonate metal salt or a sulfite metal salt, and the ionizable normal salt is continuously injected in an amount of 70 to 1200 ppm based on the total weight of the vinyl chloride monomer when a polymerization conversion rate is in a range of 0% to 20%. The method capable of preparing a vinyl chloride-based polymer suitable as an eco-friendly material, while not affecting the rate of polymerization reaction and decreasing the generation amount of total volatile organic compounds by controlling the injection time, injection amount and kind of the ionizable normal salt, is provided.

Abstract: The present disclosure relates to a composition for preparing a vinyl chloride-based polymer and a method of preparing a vinyl chloride-based polymer using the same, and provides the composition giving excellent productivity for preparing a vinyl chloride-based polymer includes while maintaining excellent foaming and viscosity properties of a plastisol including the prepared vinyl chloride-based polymer, by including a pH regulator composed of a carbonate-based metal salt, and a transition metal catalyst in the composition, and controlling an amount of the transition metal catalyst, and controlling an amount of a reducing agent such that a trace amount or none of the reducing agent is included, and the method of preparing a vinyl chloride-based polymer using the same.

Abstract: Disclosed herein is an untact DC electric-field sensor having improved sensitivity. The untact DC electric-field sensor has a circuit composed of a variable capacitor and an RF generator and improves sensitivity through resonance of the circuit by connecting an inductor to the sensor.

Abstract: A rotor and a turbo machine including the same are provided. The rotor includes a disk including a disk slot, a blade including a root member inserted into the disk slot and an airfoil disposed outside the root member in a radial direction of the disk, a locking sheet disposed inside the root member in the radial direction, and a fixing portion disposed inside the root member in the radial direction and configured to fix the locking sheet to the root member.

Abstract: A rotor and a turbo machine including the same are provided. The rotor includes a disk including a disk slot, a blade including a root member inserted into the disk slot and an airfoil disposed outside the root member in a radial direction of the disk, a locking sheet disposed inside the root member in the radial direction, and a fixing portion disposed inside the root member in the radial direction and configured to fix the locking sheet to the root member.

Abstract: Disclosed herein are a bucket vibration damping structure and a bucket and turbomachine having the same. The bucket vibration damping structure comprises a plurality of blades disposed on a plurality of buckets mounted on an outer peripheral surface of a rotor disk and a variable contact-type vibration damping means disposed on the plurality of blades and performing variable contact according to rotational speed of a rotor for damping vibration. The variable contact-type vibration damping means may comprise a first damping member disposed on one of the blades, and a second damping member disposed at a position corresponding to the first damping member on the other blade. According to the disclosure, it is possible to effectively damp vibration while performing variable contact according to the rotational speed of a turbine.

Abstract: A rotatable body includes a rotor and n buckets, each bucket being coupled to the rotor in a tangential entry manner. The rotor supports each of the n buckets coupled to the rotor, so the buckets may be stably coupled to the rotor, using a unified annular dovetail tenon that protrudes axially from the rotor. Each bucket includes a bucket dovetail mortise for engaging with the unified annular dovetail tenon in order to couple the bucket to the rotor. A method of manufacturing the rotatable body includes assembling first to (n?1)th buckets with the rotor wheel by successively inserting the first to (n?1)th buckets through the tangential entry; assembling the nth bucket with the adapter; assembling the adapter with the rotor wheel, by inserting the adapter assembled with the nth bucket into the tangential entry; and collectively moving all the buckets by one half pitch in the circumferential direction.

Abstract: A rotatable body includes a rotor and n buckets, each bucket being coupled to the rotor in a tangential entry manner. The rotor supports each of the n buckets coupled to the rotor, so the buckets may be stably coupled to the rotor, using a unified annular dovetail tenon that protrudes axially from the rotor. Each bucket includes a bucket dovetail mortise for engaging with the unified annular dovetail tenon in order to couple the bucket to the rotor. A method of manufacturing the rotatable body includes assembling first to (n?1)th buckets with the rotor wheel by successively inserting the first to (n?1)th buckets through the tangential entry; assembling the nth bucket with the adapter; assembling the adapter with the rotor wheel, by inserting the adapter assembled with the nth bucket into the tangential entry; and collectively moving all the buckets by one half pitch in the circumferential direction.

Abstract: A rotatable body includes a rotor and n buckets, each bucket being coupled to the rotor in a tangential entry manner. The rotor supports each of the n buckets coupled to the rotor, so the buckets may be stably coupled to the rotor, using a unified annular dovetail tenon that protrudes axially from the rotor. Each bucket includes a bucket dovetail mortise for engaging with the unified annular dovetail tenon in order to couple the bucket to the rotor. A method of manufacturing the rotatable body includes assembling first to (n?1)th buckets with the rotor wheel by successively inserting the first to (n?1)th buckets through the tangential entry; assembling the nth bucket with the adapter; assembling the adapter with the rotor wheel, by inserting the adapter assembled with the nth bucket into the tangential entry; and collectively moving all the buckets by one half pitch in the circumferential direction.

Abstract: A rotatable body includes a rotor and n buckets, each bucket being coupled to the rotor in a tangential entry manner. The rotor supports each of the n buckets coupled to the rotor, so the buckets may be stably coupled to the rotor, using a unified annular dovetail tenon that protrudes axially from the rotor. Each bucket includes a bucket dovetail mortise for engaging with the unified annular dovetail tenon in order to couple the bucket to the rotor. A method of manufacturing the rotatable body includes assembling first to (n?1)th buckets with the rotor wheel by successively inserting the first to (n?1)th buckets through the tangential entry; assembling the nth bucket with the adapter; assembling the adapter with the rotor wheel, by inserting the adapter assembled with the nth bucket into the tangential entry; and collectively moving all the buckets by one half pitch in the circumferential direction.

Abstract: Disclosed herein are a bucket vibration damping structure and a bucket and turbomachine having the same. The bucket vibration damping structure comprises a plurality of blades disposed on a plurality of buckets mounted on an outer peripheral surface of a rotor disk and a variable contact-type vibration damping means disposed on the plurality of blades and performing variable contact according to rotational speed of a rotor for damping vibration. The variable contact-type vibration damping means may comprise a first damping member disposed on one of the blades, and a second damping member disposed at a position corresponding to the first damping member on the other blade. According to the disclosure, it is possible to effectively damp vibration while performing variable contact according to the rotational speed of a turbine.