Antioxidant and antidiabetic activities of extracts from Cirsium japonicum roots

Jie Yin,Seong-Il Heo,Myeong-Hyeon Wang 한국영양학회 2008 Nutrition Research and Practice Vol.2 No.4

This study investigated the antioxidant activity of methanol (MeOH) and water extracts from roots of Cirsium japonicum in vitro. MeOH extract showed a stronger free radical scavenging activity than water extract. However, both of extracts showed a concentration dependent hydroxyl radical scavenging activity, reducing power and metal chelating ability. MeOH extract had greater phenolic and flavonoid contents than water extract. The antidiabetic activity of these two extracts was evaluated by the α-glucosidase inhibition assay. The water extract showed a considerable α-glucosidase inhibitory activity. To our knowledge, this may be the first time to report the antioxidant and antidiabetic activities in Cirsium japonicum roots.

The antioxidant and cytotoxic activities of Sonchus oleraceus L. extracts

Jie Yin,Gu-Joong Kwon,Myeong-Hyeon Wang 한국영양학회 2007 Nutrition Research and Practice Vol.1 No.3

This study investigated in vitro antioxidant activity of Sonchus oleraceus L. by extraction solvent, which were examined by reducing power, hydroxyl radical-scavenging activity(HRSA) and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assays. 70% MeOH extract had the greatest reducing power while EtOH extract had the greatest HRSA. The antioxidant activity of S. oleraceus extracts was concentration dependent and its IC50 values ranged from 47.1 to 210.5 ㎍/㎖ and IC?? of 70% MeOH, boiling water and 70% EtOH extracts were 47.1, 52.7 and 56.5 ㎍/㎖, respectively. 70% MeOH extract of S. oleraceus contained the greatest amount of both phenolic and flavonoid contents. The extracts tested had greater nitrite scavenging effects at lower pH conditions. The cytotoxic activity showed that EtOH extract had the best activity against the growth of stomach cancer cell. These results suggest that S. oleraceus extract could be used as a potential source of natural antioxidants.

Antioxidant Activity of Fractions from 70% Methanolic Extract of Sonchus oleraceus L.

Jie Yin,Seong-Il Heo,Mee Jung Jung,Myeong-Hyeon Wang 한국식품과학회 2008 Food Science and Biotechnology Vol.17 No.6

The potential antioxidant activities of different fractions from a 70% methanolic (MeOH) extract of Sonchus oleraceus were assayed in vitro. All of the fractions exception of n-hexane showed a strong antioxidant activity, especially the ethyl acetate (EtOAc) fraction, which showed the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity (IC??=19.25 ㎍/㎖). The results of hydroxyl radical scavenging activity and a reducing power assay showed concentration dependence, the EtOAc fraction demonstrating a better result than the other fractions at the same concentration in the studies. Additionally, the fractions’ total phenolic (TP) contents was measured, phenolic compounds such as tannic acid, p-coumatric acid, quercetin, epicathchin, and kaempferol being detected by high performance liquid chromatography (HPLC). Meanwhile, a regression analysis revealed a moderate-to-high correlation coefficient between the antiradical activity and the TP contents, suggesting that fractions obtained from the 70% MeOH extract of S. oleraceus are of potential use as sources of antioxidant material.

Effect of Salinity on Strength Behavior of Cement-treated Dredged Clay at High Initial Water Contents

Jie Yin,Wen-xia Han,Gui-zhong Xu,Ming-ming Hu,Yong-hong Miao 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.10

This paper presents the experimental investigation into the effect of salinity on the strength behavior of cement-stabilized dredged clays as fills at high initial water contents. One source of dredged clay was dredged from Baima Lake of China. Specimens were prepared having different porewater salinities by blending the air-dried clays with NaCl solution at different salt concentrations. The prepared saline dredged clay specimens were thereafter adjusted to different initial water contents and blended with cement with different amounts. Unconfined compression tests were performed on cement-stabilized dredged clay specimens after 28-day curing. All tested specimens show strain softening behavior where the axial strain corresponding to the peak stress varies with amount of cement. Stress-strain curve for the specimen with lower salinity lies above on that of higher one. Initial water content has a negative effect on the strength of cement-treated clays while cement has a positive effect on the development of strength for cement-treated dredged clays due to the pozzolanic reactions. The presence of salt has an adverse influence on the obtaining of strength for cement-treated dredged clays because salt can inhibit cement from generating C-S-H and C-A-H. Unconfined compressive strength almost linearly decreases with the increasing salinity. A quantitative expression was presented to calculate the unconfined compressive strength for cement-treated saline dredged clays concerning the effects for initial water content, porewater salinity and amount of cement.

Antioxidant Activity of Flavonoids and Their Glucosides from Sonchus oleraceus L

( Jie Yin ),( Chuan Ling Si ),( Myeong Hyeon Wang ) 한국응용생명화학회 2008 Journal of Applied Biological Chemistry (J. Appl. Vol.51 No.2

중국 민법전(계약편)상 이행정지권의 문제점과 개선방안 - CISG와의 비교를 중심으로 -

윤걸(Jie Yin),허재창(Jae-chang Huh) 한국무역상무학회 2020 貿易商務硏究 Vol.88 No.-

이행기전 계약위반은 ‘예견되는 계약위반"이라고도 하는데 19세기 중반 영국에서 최초로 확립되었으며, 계약의 효력이 발생하여 당사자 일방이 그 계약의 이행이 완료되기 전에 계약 불이행 또는 불이행에 대한 분명한 의사 표시를 하는 것을 말한다. CISG는 1980년에 이 제도를 도입하였고, 이행기전 계약위반 정도의 차이에 따라 이행정지와 계약해제의 구제조치가 마련되었다. 중국은 영미법과 CISG의 경험을 바탕으로 1999년 중국계약법에 이 제도를 처음 도입하였고, 2020년 중국 민법전을 공포하였다. 그러나 관련 조항이 너무 간략하고 불안항변권과 교차 및 중첩돼 논란이 많았다. 본 연구는 문헌연구의 방식을 통해 이행기전 계약위반에 대한 구제수단 중 이행정지권에 관한 CISG 및 중국 민법전상의 관련 규정의 비교 분석을 통해 관련 규정에 대한 이해를 높이고 나아가 중국 민법전의 이행정지권의 문제점과 개선방안을 제시하고자 함에 그 목적이 있다. Anticipatory breach of contract, was first established in the UK in the mid-19th century and it means that after the contract takes effect, one of the parties clearly expresses or indicates by its own actions that he will not perform or cannot perform the contract before performance is due. Remedies against anticipatory breach of contract cannot only effectively reduce losses caused by actual breach but also resolve contract disputes in time. CISG was introduced to this scheme in 1980, and remedial measures were established in response to differences in the degree of breach of contract prior to implementation (Article 71 'Right to suspend performance' and Article 72 'Right to avoid the contract'). Based on the experience of the Anglo-American Law and the CISG, China first introduced the system in the Chinese Contracts Act in 1999, and promulgated the Civil Code of China in 2020. However, there was a lot of controversy because the relevant clauses were too brief and crossed and overlapped with the right to protest unrest. The purpose of this study is to enhance understanding of the relevant regulations and further to present the problems and improvements of the right to suspend performance under Chinese Civil Code by comparing and analyzing the relevant regulations in CISG and Chinese Civil Code on the right to suspend performance against anticipated breach of contract.

PICC에서 사정변경의 원칙에 관한 사례 연구

윤걸 ( Yin Jie ),허재창 ( Huh Jae-chang ) 경남대학교 산업경영연구소 2023 지역산업연구 Vol.46 No.2

본 연구는 국제무역계약의 사정변경원칙의 실무적용에서 유의점을 분석하는 것을 목적으로 한다. 사정변경이란 계약체결 당시 계약의 기초가 되었던 제반 사정이 계약이 성립된 이후 크게 변경되는 것을 말한다. 국제무역계약을 이행하는 과정에서 당사자의 책임이 아닌 우발적인 사태가 발생하여 당사자의 이익이 심각하게 훼손되는 경우 가장 일반적으로 선호되는 것은 사정변경원칙을 행사하는 구제조치이다. 이러한 경우 신의성실 및 당사자 간의 권리의무의 균형을 실현하기 위해 당사자는 면책상태에서 원래 계약의 변경 또는 해제를 허용한다. 그러나 관련한 사례를 분석해 본 결과 사정변경의 원칙을 실무적으로 적용할 때 분쟁이 자주 발생하는 것으로 나타났다. 따라서 본 연구에서는 PICC를 주요 연구대상으로 하여 주로 제6.2.1조, 제6.2.2조, 제6.2.3조를 고찰하며, PICC상 사정변경원칙에 관한 이론적 내용을 해석하여 적용범위, 구성요건 및 법적효력 등에 관한 규정을 살펴보았다. 그리고 PICC의 사정변경 관련 사례를 시장환경의 변화, 불가항력의 발생, 계약의 성실한 이행, 기타의 4가지 범주로 분류하고, 각 측면에 대한 실무적 차원에서 당사자의 유의점을 제시하였다. This study aims to analyze the points of consideration in the practical application of the principle of change of circumstances in international trade contracts. The change of circumstances refers to the fact that the various circumstances that were the basis of the contract when the contract was signed changed dramatically after the contract was established. In this case, in order to achieve the good faith of the contract and the balance of rights and obligations between the parties, the parties are allowed to change or cancel the original contract under the exemption status. However, the results of the analysis of relevant cases showed that disputes often occur when the principle of change of circumstances was applied in practice. Therefore, this study takes PICC as the main research object, mainly examines Articles 6.2.1, 6.2.2, and 6.2.3, analyzes the theoretical content of the principle of change of circumstances in PICC and examines its application scope, constituent elements, legal effect, and other relevant provisions. At the same time, the relevant cases involving PICC changes are divided into four categories: changes in the market environment, the occurrence of force majeure, the honest performance of contracts, and others, and put forward the points of consideration from various practical perspectives.

Equivalent Magnetic Circuit Model for Consequent Pole Hybrid Excitation Synchronous Machine with AC Field Control

Jie Wu,Jing Yin,Baixing Zhuang,Mingjie Wang,Jitao Zhang 한국자기학회 2019 Journal of Magnetics Vol.24 No.4

At present, almost all hybrid excitation machines (HEMs) apply DC field current to control the air-gap flux. However, the DC field control mode results in a problem that the capability of field-weakening is not equal to that of field-strengthening. This paper briefly explains the mechanism of asymmetric bidirectional field control capability in present HEMs, proposes a consequent pole hybrid excitation synchronous (CPHES) machine with AC field control mode to solve the asymmetric problem. The structure and principles of CPHES machine are presented. Additionally, the equivalent magnetic circuit model of CPHES machine is derived to reduce the computational complexity of analyzing CPHES structure by using three-dimensional finite element analysis (3DFEA). The proposed equivalent model and 3D-FEA are compared, the results verify the proposed model is basically consistent with the 3D-FEA, and the proposed model is able to reduce the computational complexity greatly.

Oxidation behavior of YAG-ZrB2 ceramics prepared by spark plasma sintering

Jie-Guang Song,Da-Ming Du,Yin-Yan Ju,Yang-Liang Li,Shi-Bin Li,Gang-Chang Ji 한양대학교 세라믹연구소 2010 Journal of Ceramic Processing Research Vol.11 No.4

ZrB2 and YAG are widely applied because of some excellent properties, but ZrB2 is easily oxidized in high-temperature air. To make ZrB2 ceramics have better oxidation resistance, high-density YAG-ZrB2 ceramics were prepared. The oxidation behavior of YAG-ZrB2 ceramics is investigated at different temperatures. The results indicate that the enhanced weight change differs according to the temperature range, slightly in the temperature 900-1000oC, sharply from 1100-1300 and smoothly above 1300oC. The weight change rate of YAG-ZrB2 ceramics is increased by prolonging the oxidation time, but the weight change rate of YAG-ZrB2 ceramics is gradually reduced. The oxidation layer is porous as compared to the YAG-ZrB2 ceramics layer.

Numerical simulation investigation on centrifugal compressor performance of turbocharger

Jie Li,Yuting Yin,Shuqi Li,Jizhong Zhang 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.6

In this paper, the mathematical model of the flow filed in centrifugal compressor of turbocharger was studied. Based on the theory of computational fluid dynamics (CFD), performance curves and parameter distributions of the compressor were obtained from the 3-D numerical simulation by using CFX. Meanwhile, the influences of grid number and distribution on compressor performance were investigated,and numerical calculation method was analyzed and validated, through combining with test data. The results obtained show the increase of the grid number has little influence on compressor performance while the grid number of single-passage is above 300,000. The results also show that the numerical calculation mass flow rate of compressor choke situation has a good consistent with test results,and the maximum difference of the diffuser exit pressure between simulation and experiment decrease to 3.5% with the assumption of 6kPa additional total pressure loss at compressor inlet. The numerical simulation method in this paper can be used to predict compressor performance, and the difference of total pressure ratio between calculation and test is less than 7%, and the total-to-total efficiency also have a good consistent with test.