Dynamic Recrystallization Mechanism and Precipitation Behavior of Mg-6Gd-3Y-3Sm-0.5Zr Alloy During Hot Compression

Miaomiao Li,Miaomiao Li,Dening Zou,Yunong Li,Libo Tong1 대한금속ᆞ재료학회 2023 METALS AND MATERIALS International Vol.29 No.2

904L super austenitic stainless steel is prone to harmful secondary phase precipitation, which reduces corrosion resistance. The cooling rate during the solidification of steel is one of the critical factors affecting the precipitation of brittle phases instainless steel metals. In this paper, the effect of the cooling rates (6, 50, 100, 500, and 1000 °C min−1) on the initial corrosionbehavior of 904L steel in a simulated flue gas desulfurization (FGD) solution was studied by electrochemical measurementsand microscopic morphology observation. The results show that as the cooling rates increases, the primary solidification temperatureand the secondary dendrite arm spacing decrease. The precipitated phase in the steel is a σ-phase mainly distributedinterdendrites and forms zones of chromium and molybdenum depletion, reducing pitting resistance. With the increase in thecooling rate, the corrosion resistance increases first and then decreases, and reaches the maximum at 100 °C min−1. At thesame time, different cooling rates result in different contents of Cr and Mo in σ phase. At 100 °C min−1, the concentrationgradient of Cr and Mo near the interdendrites is the lowest compared with other cooling rates, which inhibits the growthrate of the σ phase nuclei and produces a more uniform microstructure. Corrosion test results show that pitting corrosion issensitive to the increase in the contents of Cr and Mo in the σ phase. The higher the content of Cr and Mo in the σ phase, themore serious the depletion of Cr and Mo near the interdendrites, and the worse the corrosion resistance.

A biodegradable drug‐controlled delivery system based on mesoporous manganese dioxide and poly(dopamine)

Li Miaomiao,Cai Wenrong,Jiang Lihua,Li Junyao,Li Shan,Tang Tongtong,Kong Yong 대한화학회 2023 Bulletin of the Korean Chemical Society Vol.44 No.12

Mesoporous manganese dioxide (mMnO 2 ) was first synthesized for the loading of methotrexate (MTX), and then dopamine was in situ polymerized on the surface of the MTX‐loaded mMnO 2 (mMnO 2 ‐MTX) in an alkaline solution to encapsulate the drug in the mesopores of mMnO 2 . Both low pH and glutathione (GSH) can result in the degradation of mMnO 2 and poly(dopamine) (PDA), and thus the delivery of MTX from the mMnO 2 ‐MTX‐PDA can be triggered by low pH and GSH. Near‐infrared (NIR) light‐responsive delivery of MTX can be achieved owing to the outstanding photothermal conversion capability of PDA; on the other hand, the mMnO 2 ‐MTX‐PDA can be utilized for photothermal therapy under the irradiation of NIR light due to the elevated temperature. The results of cytotoxicity test demonstrate that the pH, GSH, and NIR light tri‐responsive drug‐controlled delivery system has excellent biocompatibility, while exhibits pronounced growth inhibition against murine breast tumor cell line 4T1. Mesoporous manganese dioxide (mMnO2) was first synthesized for the loading of methotrexate (MTX), and then dopamine was in situ polymerized on the surface of the MTX-loaded mMnO2 (mMnO2-MTX) in an alkaline solution to encapsulate the drug in the mesopores of mMnO2. Both low pH and glutathione (GSH) can result in the degradation of mMnO2 and poly(dopamine) (PDA), and thus the delivery of MTX from the mMnO2-MTX-PDA can be triggered by low pH and GSH. Near-infrared (NIR) light-responsive delivery of MTX can be achieved owing to the outstanding photothermal conversion capability of PDA; on the other hand, the mMnO2-MTX-PDA can be utilized for photothermal therapy under the irradiation of NIR light due to the elevated temperature. The results of cytotoxicity test demonstrate that the pH, GSH, and NIR light triresponsive drug-controlled delivery system has excellent biocompatibility, while exhibits pronounced growth inhibition against murine breast tumor cell line 4T1.

Effect of Cooling Rate on Pitting Corrosion Behavior of 904L Austenitic Stainless Steel in a Simulated Flue Gas Desulfurization Solution

Miaomiao Li,Dening Zou,Yunong Li,Libo Tong 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.3

904L super austenitic stainless steel is prone to harmful secondary phase precipitation, which reduces corrosion resistance. The cooling rate during the solidification of steel is one of the critical factors affecting the precipitation of brittle phases instainless steel metals. In this paper, the effect of the cooling rates (6, 50, 100, 500, and 1000 °C min−1) on the initial corrosionbehavior of 904L steel in a simulated flue gas desulfurization (FGD) solution was studied by electrochemical measurementsand microscopic morphology observation. The results show that as the cooling rates increases, the primary solidification temperatureand the secondary dendrite arm spacing decrease. The precipitated phase in the steel is a σ-phase mainly distributedinterdendrites and forms zones of chromium and molybdenum depletion, reducing pitting resistance. With the increase in thecooling rate, the corrosion resistance increases first and then decreases, and reaches the maximum at 100 °C min−1. At thesame time, different cooling rates result in different contents of Cr and Mo in σ phase. At 100 °C min−1, the concentrationgradient of Cr and Mo near the interdendrites is the lowest compared with other cooling rates, which inhibits the growthrate of the σ phase nuclei and produces a more uniform microstructure. Corrosion test results show that pitting corrosion issensitive to the increase in the contents of Cr and Mo in the σ phase. The higher the content of Cr and Mo in the σ phase, themore serious the depletion of Cr and Mo near the interdendrites, and the worse the corrosion resistance.

Causal relationship among quality factors, emotional responses, and satisfaction of school food service in Henan province, China

Miaomiao Li,Lee Young Eun 한국영양학회 2023 Nutrition Research and Practice Vol.17 No.2

BACKGROUND/OBJECTIVES: School food service has played an important role in promoting the health and physical condition of students by providing students with a balanced and nutritious diet. Therefore, boosting the quality of school food service and improving the students’ satisfaction is critical. For this purpose, this study examined the structural causal relationship among the quality of school food service factors, emotional responses, and satisfaction in China. SUBJECTS/METHODS: This study was conducted with 4th–6th-grade students from 6 junior high schools in Henan province of China, with 590 questionnaire responses (87.3%) collected and statistically analyzed. RESULTS: The school food service quality factors (including menu management, dietary education, facilities management, price and food distribution management, and personal hygiene during meals) must be enhanced to boost the students’ satisfaction. In addition, the study used questionnaire survey data to validate the full mediation of students’ emotional responses between school food service quality factors and student satisfaction. CONCLUSIONS: Students’ emotions also play an important role in influencing the quality of school food service, all of which affect the emotional responses of students. Therefore, students’ positive emotions are an important indicator for improving the quality of school food service. A national support policy is necessary for the ongoing maintenance and development of various programs that drive students' satisfaction and promote the adoption of education guidelines for school food service in China.

Emulsifying properties of different soy hull pectin polysaccharides and application in mayonnaise

Jun Li,Huaitian Cui,Xinyue Xu,Jiayi Li,Miaomiao Lu,Xijie Guan,Danshi Zhu,He Liu 한국식품과학회 2022 Food Science and Biotechnology Vol.31 No.6

Soy hull pectic polysaccharide (SHPP) is a kindof biological macromolecule prepared from soy hull, whichhas certain thickening and gel properties. In present study,SHPP was extracted with citric acid and sodium citratefrom soybean hulls under the assistance of microwave,respectively. SHPPs were then compared with commercialpectin polysaccharide to test their emulsification ability. The emulsion prepared from SHPP extracted with sodiumcitrate has the best emulsifying effect, small particle sizeand uniform distribution. The rheological properties andparticle size distribution of mayonnaise did not changesignificantly after the addition of different SHPPs andcommercial pectin polysaccharides. However, microscopicobservations revealed that the droplets were more uniformlydistributed in the mayonnaise after the addition ofSHPP extracted with sodium citrate under the assistance ofmicrowave and commercial pectin APC141. SHPPextracted with sodium citrate may play an important role inmaintaining emulsion stability in the future.

Study of a Three-Dimensional and Multi-Functional Urban High-Rise Complex in the High-Density Environment: Design Practice of Yiwu World Trade Center

Li, Linxue,Hou, Miaomiao,Zhang, Qi Council on Tall Building and Urban Habitat Korea 2019 International journal of high-rise buildings Vol.8 No.1

Facing the challenges of urban form and space quality in a high-density environment, the paper puts forward the development trend of three-dimensional and multi-functional design for an urban high-rise complex, and analyzes the design methods of establishing an urban landmark, including multi-functional composition, three-dimensional space integration, three-dimensional traffic organization and energy flow programming. Meanwhile, combined with the specific design case of Yiwu World Trade Center, the practical experience of designing a high-rise complex in China's medium-sized cities is analyzed.

PATH TRACKING FOR AUTONOMOUS RACE CAR BASED ON G-G DIAGRAM

Miaomiao Fu,Jun Ni,Xueyuan Li,Jibin Hu 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.4

Currently, the autonomous driving technique is attracting increasing research focus from all over the world. Generally, the control systems of an autonomous vehicle include environment perception, path planning and path tracking control systems. In this paper, the path tracking control issue of the autonomous vehicle will be focused on. Few of the previous proposed path tracking controllers consider the vehicle driving and handling limit, which degenerates the potential of the autonomous vehicle to finish the desired path as quick as possible. To this end, this paper proposes a path tracking controller for autonomous vehicle, which aims at pushing it to the driving and handling limit. The limit dynamic performance of the autonomous vehicle is represented by the G-G diagram, which indicates the acceleration capability of the autonomous vehicle. The G-G diagram is obtained by phase portrait method and it is validated by a modified FSAE racing car. Finally, a path tracking controller based on the G-G diagram is proposed. The simulation validation results demonstrate the effectiveness of the proposed controller.

Molecular Characterization of Burkholderia cepacia Complex Isolates Causing Bacterial Fruit Rot of Apricot

Li, Bin,Fang, Yuan,Zhang, Guoqing,Yu, Rongrong,Lou, Miaomiao,Xie, Guanlin,Wang, Yanli,Sun, Guochang The Korean Society of Plant Pathology 2010 Plant Pathology Journal Vol.26 No.3

The Burkholderia cepacia complex isolates causing bacterial fruit rot of apricot were characterized by speciesspecific PCR tests, recA-HaeIII restriction fragment length polymorphism (RFLP) assays, rep-PCR genomic fingerprinting, recA gene sequencing, and multilocus sequence typing (MLST) analysis. Results indicated that the isolates Bca 0901 and Bca 0902 gave positive amplifications with primers specific for B. vietnamiensis while the two bacterial isolates showed different recA-RFLP and rep-PCR profiles from those of B. vietnamiensis strains. In addition, the two bacterial isolates had a higher proteolytic activity compared with that of the non-pathogenic B. vietnamiensis strains while no cblA and esmR marker genes were detected for the two bacterial isolates and B. vietnamiensis strains. The two bacterial isolates were identified as Burkholderia seminalis based on recA gene sequence analysis and MLST analysis. Overall, this is the first characterization of B. seminalis that cause bacterial fruit rot of apricot.

Identification of AMPK activator from twelve pure compounds isolated from Aralia Taibaiensis: implication in antihyperglycemic and hypolipidemic activities

Li, Yuwen,Park, Jongsun,Wu, Yin,Cui, Jia,Jia, Na,Xi, Miaomiao,Wen, Aidong The Korean Society of Pharmacology 2017 The Korean Journal of Physiology & Pharmacology Vol.21 No.3

The root bark extract of Aralia taibaiensis is used traditionally for the treatment of diabetes mellitus in China. The total saponin extracted from Aralia Taibaiensis (sAT) has effective combined antihyperglycemic and hypolipidemic activities in experimental type 2 diabetic rats. However, the active compounds have not yet been fully investigated. In the present study, we examined effects of twelve triterpenoid saponins on AMP-activated protein kinase (AMPK) activation, and found that compound 28-O-${\beta}$-D-glucopyranosyl ester (AT12) significantly increased phosphorylation of AMPK and Acetyl-CoA carboxylase (ACC). AT12 effectively decreased blood glucose, triglyceride (TG), free fatty acid (FFA) and low density lipoprotein-cholesterol (LDL-C) levels in the rat model of type 2 diabetes mellitus (T2DM). The mechanism by which AT12 activated AMPK was subsequently investigated. Intracellular ATP level and oxygen consumption were significantly reduced by AT12 treatment. The findings suggested AT12 was a novel AMPK activator, and could be useful for the treatment of metabolic diseases.

Molecular Characterization of Burkholderia cepacia Complex Isolates Causing Bacterial Fruit Rot of Apricot

Bin Li,Yuan Fang,Guoqing Zhang,Rongrong Yu,Miaomiao Lou,Guanlin Xie,Yanli Wang,Guochang Sun 한국식물병리학회 2010 Plant Pathology Journal Vol.26 No.3

The Burkholderia cepacia complex isolates causing bacterial fruit rot of apricot were characterized by speciesspecific PCR tests, recA-HaeIII restriction fragment length polymorphism (RFLP) assays, rep-PCR genomic fingerprinting, recA gene sequencing, and multilocus sequence typing (MLST) analysis. Results indicated that the isolates Bca 0901 and Bca 0902 gave positive amplifications with primers specific for B. vietnamiensis while the two bacterial isolates showed different recARFLP and rep-PCR profiles from those of B. vietnamiensis strains. In addition, the two bacterial isolates had a higher proteolytic activity compared with that of the non-pathogenic B. vietnamiensis strains while no cblA and esmR marker genes were detected for the two bacterial isolates and B. vietnamiensis strains. The two bacterial isolates were identified as Burkholderia seminalis based on recA gene sequence analysis and MLST analysis. Overall, this is the first characterization of B. seminalis that cause bacterial fruit rot of apricot.