How to resolve the trade-off between performance and long-term stability of magnetorheological fluids

Choi Junsok,Lim Junyoung,Han Sangsok,Kim Hoyeon,Choi Hyoung Jin,Seo Yongsok 한국유변학회 2022 Korea-Australia rheology journal Vol.34 No.4

A suspension of micro- or nano-magnetic particles dispersed in a nonmagnetic carrier medium is called a magnetorheological (MR) fluid. MR fluids are smart materials that undergo rapid and reversible changes in rheological properties under an external magnetic fi eld. The rheological properties of MR fluids can be easily controlled through manipulation of the magnetic fi eld strength. Because of their unique and fast reversible changes in rheological properties, MR fluids are widely used in various devices and structures. However, they suffer long-term stability (particle sedimentation) problems because of the density mismatch between the suspended magnetic particle and the liquid medium. In previous studies, researchers have expended great eff orts to simultaneously improve the stability and performance of MR fluids. Nevertheless, a trade-off relationship exists between the stability and the performance of MR fluids, that is, as MR performance increases, stability decreases, and vice versa. In this review, we recapitulate the findings of our group's recent achievements and address the conflicting issues. Reviewing the various routes will provide clues to solving the trade-off problem and suggest a guideline for developing high-performance and highly stable MR fluids.

Evaluation of computed tomographic and radiographic myelography in normal miniature pigs

Choi, Mihyun,Lee, Hyeyeon,Kim, Mieun,Kim, Junyoung,Lee, Namsoon,Chang, Jinhwa,Jung, Joohyun,Choi, Mincheol The Korean Society of Veterinary Science 2010 大韓獸醫學會誌 Vol.50 No.1

Evaluation of the myelography was studied in miniature pigs. Radiographs and computed tomographic (CT) images of the whole spine were obtained at clinically healthy twelve miniature pigs of 4 (8.7-10 kg) and 12 (26-31 kg) months. The assessments of the spinal cord were made in accordance with the Pavlov's method and compared area ratio [at spinal cord (SC), vertebral canal (VC) and vertebral body (VB)]. The Pavlov's ratio in the cervical spine was significant larger than that of thoracolumbar in radiographic myelography. On CT myelography, the area of the spinal cord had a significant difference between the cervical and thoracolumbar spine. Among the cervical spine, the ratios of spinal cord and vertebral body (SC : VB), vertebral canal and vertebral body (VC : VB) were minimum at the level of 4th cervical spine in both ages, while maximum at the level of 6th cervical spine in both months. In case of lumbar spine, the ratios of spinal cord and vertebral body (SC : VB) were the largest at the level of 4th lumbar spine in 4 months and at the level of 3rd lumbar spine in 12 months. In addition, the ratio of spinal cord and vertebral body (SC : VB) of the cervical spinal cord was significant lower at 4 months but the lumbar spinal cord showed lower pattern at 12 months old miniature pigs.

Evaluation of the lateral ventricle using MRI in normal micropigs

Choi, Mihyun,Lee, Namsoon,Yi, Kangjae,Kim, Junyoung,Choi, Mincheol The Korean Society of Veterinary Science 2011 大韓獸醫學會誌 Vol.51 No.3

This study was undertaken to assess the lateral ventricle, which was some portion of brain and related to congenital anomalies, from 1, 2, 4, and 8 months of age in healthy micropigs. They were induced general anesthesia and performed magnetic resonance imaging (MRI) with a 0.3 Tesla magnet. Each age group was evaluated by three subjects such as lateral ventricular volume, ventricular volume ratio and asymmetry. T1 weighted transverse images were acquired for calculation of lateral ventricular and corresponding brain parenchyma areas. The ratio of bilateral ventricle areas used to analyze the asymmetry. The mean ventricular volumes of each month were $676.74{\pm}25.58mm^3$ (1 month-old), $630.64{\pm}143.84mm^3$ (2 month-old), $992.12{\pm}106.03mm^3$ (4 month-old) and $1172.62{\pm}237.57mm^3$ (8 month-old), respectively. The ventricular volume ratio was the smallest at 2 month-old and re-increased from that age. The ratio was significantly different between 2 month-old and other age groups (p < 0.05). The value of bilateral area ratio showed within 1.5 in all experimental animals. Consequently the lateral ventricle showed a positive correlation with aging and symmetric shapes in both sides. The developmental pattern of the lateral ventricle provides basic data in micropigs as an experimental animal model for physiological and neurosurgical approach.

원형 직류전극의 위치에 따른 프로판 예혼합 화염의 거동

최준영(Junyoung Choi),김민석(Minsuk Kim),김혜민(Hyemin Kim) 한국연소학회 2021 KOSCOSYMPOSIUM논문집 Vol.2021 No.5

수냉식 응축기를 활용한 자동차용 에어컨 시스템 효율 향상에 관한 실험적 연구

최준영(Junyoung Choi),원승식(Seungsik Won),안용남(Yongnam Ahn),신현근(Hyunkeun Shin),왕윤호(Yoonho Wang),김재연(Jaeyeon Kim) 한국자동차공학회 2014 한국자동차공학회 부문종합 학술대회 Vol.2014 No.5

Recently regulations regarding C0₂ emission and fuel economy of automobile are being increased. Accordingly power consumption reduction of Mobile Air-Conditioning system(MAC) has been continuously requested. There have been numerous attempts to use a water-cooled condenser instead of conventional air-cooled condenser in an airconditioning system. This paper describes an experimental results of using water-cooled condenser in air-conditioning system. Using additional water-cooled condenser was the most effective way among numerous water-cooled condenser systems. The water-cooled condenser cools refrigerant from superheated state to a two-phase state and the air-cooled condenser cools from two-phase state to sub cool state. This was named combined cooling condenser system which had both a water cooled condenser and an air cooled condenser. Bench and vehicle test were conducted to verify the effects to reduce power consumption due to decreased discharge pressure of air-conditioning system. By using combined cooling condenser system, A/C efficiency improved about 9.4% over the conventional A/C system.

클라우드 컴퓨팅의 보안에 관한 연구

최준영(Junyoung Choi),조성래(Sungrae Cho) 한국통신학회 2017 한국통신학회 학술대회논문집 Vol.2017 No.11

The Preparation of NiFe2O4 Thin Film Prepared by E-Beam Evaporation Method for Simulated Specimen in PWR System

Mansoo Choi,Junyoung Jung,Jungsoon Park,Wangkyu Choi,Sangyoon Park,Hui-Jun Won,Seon-Byeong Kim 한국방사성폐기물학회 2017 한국방사성폐기물학회 학술논문요약집 Vol.2017 No.10

초과배당에 따른 이익의 증여에 관한 연구

최준영(Choi Junyoung),박종수(Park Jongsu) 한국세법학회 2018 조세법연구 Vol.24 No.2

우리나라 상법에서는 주주평등원칙을 엄격하게 적용하여 차등배당을 허용하고 있지 않으므로 현재 유가증권시장(KOSPI)과 코스닥시장(KOSDAQ)에 상장된 상장회사나 비상장회사에서 이루어지고 있는 차등배당은 상법에서 규정하고있는 차등배당이 아닌 형식적으로 회사가 지급하는 배당의 형식을 취하고 있을 뿐 실질적으로는 주주총회에서 배당을 결의한 후 최대주주 등이 배당받을 권리인 구체적 이익배당청구권의 전부 또는 일부를 포기하여 소액주주 등에게 나누어 준 것으로 무상 양도 또는 증여에 해당한다. 현행 소득세법 및 상속증여세법에서는 배당을 포기한 최대주주 등은 배당에 따른 세금을 부담하지 않도록 하고 있고 초과배당을 받은 최대주주와 특수관계에 있는 주주 등에 대해서는 소득세를 부담하도록 하여 별도로 증여세를 부담하지 않도록 하고 있다. 주주총회의 배당결의에 따라 확정된 구체적 이익배당청구권의 전부 또는 일부의 포기 또는 양도의 측면에서 보면 구체적 이익배당청구권은 비록 실질적으로 배당금을 받지는 않았으나 배당금을 받은 것과 동일한 법률적 효력을 가지고 있는 실현이익임에도 불구하고 현행 과세제도에 따르면 최대주주 등의 자본이익에 대해 영구히 과세할 수 없을 뿐만 아니라 자본이익이 과세된 후 재산을 증여한 경우와 비교하여 조세 부담의 차이가 발생하여 조세평등주의에 반하는 문제점을 가지고 있다. 따라서 배당을 포기한 최대주주등은 배당소득에 대한 소득세를 부담하도록 하고 무상으로 증여 또는 양도받은 최대주주와 특수관계에 있는 주주 등은 증여세를 부담하도록 하는 것이 조세평등주의에 부합된다고 할 수 있다. 다만, 소액주주 등에 대해서만 배당을 하는 경우 소액주주 보호와 최대주주 등의 배당포기로 인한 기업재무구조의 충실 및 안정이라는 정책적 측면을 고려하여 최대주주 등이 포기한 배당에 대해서는 소득세를 부담하지 않도록 하고 초과배당금을 받은 소액주주 등이 소득세를 부담하도록 하는 것이 바람직하다. 그러나 차등배당을 통해 최대주주등이 조세의 부담을 회피하고 자신이 포기한 배당을 특수관계에 있는 주주에게 초과배당하는 경우 정책적 측면에 부합되지 않을 뿐만 아니라 조세평등주의에도 반하므로 최대주주 등과 특수관계에 있는 주주가 받는 초과배당금에 대해 배당을 포기한 최대주주등은 소득세를 부담하도록 하고 최대주주와 특수관계에 있는 주주는 증여세를 부담하도록 하는 것이 정책적 측면과 초과배당에 따른 이익의 증여 과세제도의 도입 목적과 조세평등주의에도 부합한다고 할 수 있다. 따라서 현행 상속증여세법 제41조의 2를 폐지하고 현행 문제점을 보완하여 상속증여세법 제3장 제2절 증여추정 및 증여의제에 ‘제45조의 6(초과배당에 따른 이익의 증여의제)’ 조문을 신설하여 규정하는 것이 과세제도의 도입 목적과 조세평등주의에도 부합될 뿐만 아니라 상법에서 주주평등원칙을 엄격하게 적용하여 차등배당을 허용하지 않는 것과도 일맥상통하여 관련 법률과의 조화를 이루는 효과 또한 달성할 수 있을 것이다. In the commercial law, difference dividend is not allowed due to strict stockholders’ equality principle, accordingly, difference dividend conducted in the KOSPI and KOSDAQ listed companies or unlisted companies a mere dividend form, offered by the company formally, not the difference dividend defined by the commercial law, and the actuality is a civil assignment, given to minority shareholders as the major shareholders give up the whole or some of right for concrete profit assignment, a right to dividend after resolution of dividend at the general meeting of shareholders. In the current Income Tax Law and Inheritance and Gift Tax Law, the major shareholders are not assigned with the tax along with dividend, who give up dividend, also, the shareholders in a special relationship with the major shareholders with the excess dividend are assigned with income tax, and gift tax is not separately assigned. To see the aspect of abandonment or transfer of the whole or some of confirmed right for concrete profit assignment according to dividend resolution at the general meeting of shareholder, nevertheless the right for concrete profit dividend has the equal legal effect just like receipt of dividend, though the actual dividend is a realized profit, not received, according to current tax system, it has a problem against tax equality principle due to difference in tax burden compared to transfer of property after taxation of capital gain, since the capital gain of the major shareholders could not permanently taxed. Therefore, in case of untrue difference dividend, to assign the dividend abandoned by the major shareholders to the shareholders excessively through difference dividend, in a special relationship, in order to evade tax, it does not correspond to the policy aspect, nor to tax equality principle, accordingly, it is desirable to assign income tax to the major shareholders who abandon dividend on the excessive dividend assigned to the shareholders in a special relationship with the major shareholders and assign gift tax to the shareholders in a special relationship with the major shareholders, according to the policy aspect, profit transfer taxation, and tax equality principle. Therefore, it is necessary to change the transfer date determined by current inheritance and gift tax law article 41(2) paragraph 1 to “the date decided at the general meeting of shareholders”, paragraph 2 and 3 should be deleted, also, a relevant paragraph 4 “Calculation method of income amount”, should also be deleted and revised, which is unnecessary, to correspond to taxation system.

계층적 3차원 컨볼루셔널 희소코딩을 이용한 확률적 볼륨렌더링

최준영(JunYoung Choi),Tran Minh Quan,정해진(Haejin Jeong),정원기(Won-Ki Jeong) 한국컴퓨터그래픽스학회 2017 한국컴퓨터그래픽스학회 학술대회 Vol.2017 No.7

유니티 기반 시뮬레이터를 활용한 자율주행 배송로봇을 위한 도시 설계

최준영(Junyoung Choi),김헤진(Hyejin Kim),권민지(Minji Kwon),윤성범(Sungbeom Yoon) 대한공간정보학회 2022 한국공간정보학회 학술대회 Vol.2022 No.5