Fabrication and Interface Structural Behavior of Mg/Al Thickness-Oriented Bonding Sheet via Direct Extrusion

Lei Gao,Feng Li,Ye Wang,Xing Mao Xiao,Peng Da Huo 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

Solid-state bonding of heterogeneous materials is one of the effective ways to achieve light weight. An extrusion formingprocess for Mg/Al thickness-oriented bonding sheet was carried out. Due to triaxial compressive stress in the extrusion container,the AZ31 and AA6061 billets were deformed and the bonding and forming of Mg/Al thickness-oriented sheet can berealized by this method. The observation results of the bonding position by using XRD, SEM and EDS showed that: at theforming temperature with 360–420 °C, it had a good bonding interface, and the width of the transition layer increased withthe increase of the forming temperature. The presence of brittle intermetallic compounds in the transition layer indicated thatmetallurgical bonding had occurred at the interface. Considering all factors comprehensively, when the forming temperaturewas 390 °C, the bonding quality was appropriate. Its tensile-shear strength was 42 MPa, the width of the interface transitionlayer was about 10 μm, and the microhardness was about 164.3 HV. This method provided scientific guidance and technicalreserves for green forming of Mg/Al sheets.

국내 에이즈환자에서 발견된 새로운 인간면역부전 바이러스 아형

김남중,이선희,박상원,최희정,김도마,최정윤,김진욱,김의석,Feng Gao,오명돈,최강원 대한감염학회 2001 감염 Vol.33 No.2

Backgroud : In the previous study, we determined subtypes of Human Immunodeficiency Virus type 1 (HIV-1) in Korean patients by partial sequence analysis. We showed that eighteen of the nineteen sequences of HIV-1 from Korean fell into subtype B and one fell into subtype A. At that study, HIV-1 identified as subtype A showed 40% diversity from reference sequences and presumed to be a variant of subtype A. The aim of present study is to determine the molecuar biological characteristics of HIV-1 previously identified as subtype A. Methods : Growth curve was determined. SI/NSI phenotype was determined using a cocultivation assay using MT-2 cells. A complete genome sequence was obtained by amplifying overlapping PCR fragments. Cowork was done to identify the subtype of HIV-1 previously identified as variant A from Korea (97-KRO04), Cyprus (94CY017), Democratic Republic of Congo (97CDKTB48, 97CDKFE4, 97CDKS10, 97-CDKP58). Phylogenetic analysis, distance analysis, diversity plot analysis, bootstrap anlysis were done to identify the subtype of these newly characterized strains. Results : We found that 97KR004 was SI pheno-type. Complete sequence of 97KR004 was determined (AF286239). Phylogenetic analysis showed that the four newly characterized strains (94CY017, 97CDKTB-48, 97CDKFE4, 97CDKS10) were closely related to subtype A. Subtype distance tool showed that these four strains fell to sub-subtype A2. Diversity plot an-alysis and bootstrap analysis were done to identify subtype of 97KR004. Nine subtype reference strains and 94CY017 strain were used as reference sequences. These analyses confirmed that 97KR004 represented sub-subtype A2/subtype D recombinant. Conclusion : We showed that 97KR004 fell into newly identified sub-subtype A2. (Korean J Infect Dis 33:71∼77, 2001)

NONLINEAR IMPULSIVE SYSTEM OF MICROBIAL PRODUCTION IN FED-BATCH CULTURE AND ITS OPTIMAL CONTROL

GAO, CAIXIA,LANG, YANHUAI,FENG, ENMIN,XIU, ZHILONG 한국전산응용수학회 2005 Journal of applied mathematics & informatics Vol.19 No.1

In this study the optimal control of fed-batch glycerol fermentation is investigated based on an impulsive dynamical system. Considering the sudden increase of the glycerol and alkali in fed-batch culture of biodissimilation of glycerol to 1,3-propanediol, this paper proposes a non-linear impulsive system of fed-batch culture. The existence, uniqueness and regularity properties of piecewise solution for the system are proved. In view of the controllability of volumes of glycerol added to the reactor instantaneously, the paper constructs an optimal control model based on the nonlinear impulsive system and the existence of the optimal control is obtained. The control variables here are the moments and the sizes of jumps in the states at the discrete instants and the objective is to maximize the productivity of 1,3-propanediol over one cycle.

Punicic Acid from Trichosanthes kirilowii Seed Oil Is Rapidly Metabolized to Conjugated Linoleic Acid in Rats

Gao-Feng Yuan,Jing-Qun Yuan,Duo Li 한국식품영양과학회 2009 Journal of medicinal food Vol.12 No.2

The incorporation and metabolism of orally administered punicic acid (PA), one isomer of conjugated linolenic acid (CLNA), in rat tissues and plasma were studied over a 24-hour period. The punic acid was derived from Trichosanthes kirilowii Maxim seed oil, a unique PA-containing material, and identified and analyzed by high-performance liquid chromatography and gas chromatography-mass spectrometry. The results show that PA was incorporated and metabolized to 9c,11t-conjugated linoleic acid (CLA) in rat plasma, liver, kidney, heart, brain, and adipose tissue. The level of PA and CLA in liver and plasma was higher than in brain, heart, kidney, and adipose tissue, and the lowest accumulation occurred in the brain. The observation that PA can be converted into 9c,11t-CLA has gained increased importance since it has been demonstrated that 9c,11t-CLA exerts many biological activities. Therefore natural resources containing CLNA, especially edible T. kirilowii seed, could be a potential dietary source of CLA, following PA metabolism. PA is expected to be used as a functional food and nutraceutical.

A 3D Nitrate-bridging Heterometal-azido Inorganic Polymer Containing Cd_8 Cube: Synthesis, Structure, Topology and Fluorescence

Feng Luan,Yuan Gao,Ling Xu,Bing Liu 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.5

no abstract

Control of Large Model Mismatch Systems using Multiple Models

Feng Gao,Dongfang Dang,Shengbo Eben Li,맹추 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.4

H∞ control is an effective approach to handle model uncertainties. However, when modeling mismatchis large, it tends to be challenging to meet the desired requirements of both stability and performance by only usinga single H∞ controller. This study presents a switching method to enhance the robust stability and performanceof H∞ control by dividing the range of dynamics into multiple uncertain models. The candidate robust controllersare designed by solving a set of linear matrix inequalities for each uncertain model. A structural scheduling logicthat selects the most proper controller into closed-loop is proposed. The selected controller can ensure boundedexponentially weighted H∞ norm of the closed-loop switching systems. This work analyses their robust stabilityand disturbance attenuation performance via a linear fractional transformation by using the small gain theorem. Theeffectiveness of this method is validated with a fist-order inertial system with pure time delay.

Effect of Different Tumbling Marination Treatments on the Quality Characteristics of Prepared Pork Chops

Gao, Tian,Li, Jiaolong,Zhang, Lin,Jiang, Yun,Ma, Ruixue,Song, Lei,Gao, Feng,Zhou, Guanghong Asian Australasian Association of Animal Productio 2015 Animal Bioscience Vol.28 No.2

The effect of different tumbling marination treatments (control group, CG; conventional static marination, SM; vacuum continuous tumbling marination, CT; vacuum intermittent tumbling marination, IT) on the quality characteristics of prepared pork chops was investigated under simulated commercial conditions. The CT treatment increased (p<0.05) the pH value, $b^*$ value, product yield, tenderness, overall flavor, sensory juiciness and overall acceptability in comparison to other treatments for prepared boneless pork chops. The CT treatment decreased (p<0.05) cooking loss, shear force value, hardness, gumminess and chewiness compared with other treatments. In addition, CT treatment effectively improved springiness and sensory color more than other treatments. However, IT treatment achieved the numerically highest (p<0.05) $L^*$ and $a^*$ values. These results suggested that CT treatment obtained the best quality characteristics of prepared pork chops and should be adopted as the optimal commercial processing method for this prepared boneless pork chops.

STUDY OF INTELLIGENT ENGINEERING DRAWING PROCESSING SYSTEM

Gao Guoan,Gong Mao Kai,Zhang Wei,Shen Yun Feng 대한전자공학회 1992 대한전자공학회 Conference Vol.1992 No.2

Analysis of coupled vibration characteristics of PMS grinding motorized spindle

Feng Gao,Mingke Cheng,Yan Li 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.9

Field-path-kinetic coupling and the multi-body dynamics models were established and the finite element method (FEM) was used to study the coupled vibrations of motorized spindle. The results show that the frequency is mainly 1f r at low speeds, fractional-octave and 1f r at high-speed only the bearing force. The orbit of bearing transitions is from a more pronounced circle to an approximately circular shape, while the rotor changes from a rule to a random pattern. The front bearing is more obvious than the rear and the orbits are always round; the radius of the orbit at the front bearing gradually increases as the speed increases. The result is the vibration displacement changes more significantly close to the spindle end and the amplitude increases accordingly. The experimental results show that operating conditions are closer to the normal, the influence of unbalanced magnetic pull can be neglected, the bearing selection and assembly are reasonable.

Performance and Spatial Succession of a Full-Scale Anaerobic Plant Treating High-Concentration Cassava Bioethanol Wastewater

( Gao Rui Fang ),( Xu Feng Yuan ),( Jia Jia Li ),( Xiao Fen Wang ),( Xu Cheng ),( Wan Bin Zhu ),( Zong Jun Cui ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.8

A novel two-phase anaerobic treatment technology was developed to treat high-concentration organic cassava bioethanol wastewater. The start-up process and contribution of organics (COD, total nitrogen, and NH4+-N) removal in spatial succession of the whole process and spatial microbial diversity changing when sampling were analyzed. The results of the start-up phase showed that the organic loading rate could reach up to 10 kg COD/m3d, with the COD removal rate remaining over 90% after 25 days. The sample results indicated that the contribution of COD removal in the pre-anaerobic and anaerobic phases was 40% and 60%, respectively, with the highest efficiency of 98.5%; TN and NH4+-N had decreased to 0.05 g/l and 0.90 g/l, respectively, and the mineralization rate of total nitrogen was 94.8%, 76.56% of which was attributed to the anaerobic part. The microbial diversity changed remarkably among different sample points depending on the physiological characteristics of identified strains. Moraxellaceae, Planococcaceae, and Prevotellaceae were dominant in the pre-anaerobic phase and Bacteroidetes, Campylobacterales, Acinetobacter, Lactobacillus, Clostridium, and Bacillus for the anaerobic phase. Methanosarcinaceae and Methanosaeta were the two main phylotypes in the anaerobic reactor.