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Lang Huang,Xu Yang,Bin Zhang,Liang Qiao,Hongchang Li,Mofan Tian 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6
The modular multilevel matrix converter (M3C) applied to a low frequency alternating current (LFAC) transmission system is investigated. Due to the complexity and tight coupling of the converter, a novel hierarchical model predictive control (MPC) scheme with a cascaded structure of power control, capacitor voltage averaging and balancing control for M3C is proposed. The terminal behavioral model of M3C is derived out and the fast separated space-vectors approximation method is realized. The proposed scheme clearly achieves the system-level multi-objective control without the empirical procedure of the weighting factor design and significantly reduces the computational cost. This is the first time to apply the MPC to a converter in a hierarchical structure. Simulation results of a 7-level M3C are provided to illustrate the system’s performance.
Lang He,Sheng Li,Chengzhi Xu,Benmei Wei,Juntao Zhang,Yuling Xu,Beirong Zhu,Yang Cao,Xilin Wu,Zhijin Xiong,Rongrui Huang,Jian Yang,Haibo Wang 한국고분자학회 2020 Macromolecular Research Vol.28 No.9
Pure collagen materials are expensive with poor mechanical properties, which need modifications in most cases. As the degradation product of collagen, gelatin is cheap, degradable and biocompatible, but few literatures have reported the research about gelatin-collagen composite materials. This is because gelatin and collagen have different soluble temperatures—gelatin is soluble in hot water (≥30 oC) and swells in cold water. However, a low temperature (2-10 oC) is required to prepare and store collagen solution, and neutral collagen solution denatures quickly above the room temperature. In this study, gelatin was ground into powders and swelled in neutral bovine tendon pepsin-soluble collagen solution (BPSC) to form a homogeneous gelatin-collagen mixture, in light of the swelling characteristics of gelatin in cold water. The assembly properties and gel properties of this composite material were further studied. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) test results showed that the bovine tendon collagen had typical type-I collagen structural characterizations with two α chains of about 100 kDa and one β chain of about 200 kDa; while the SDS-PAGE pattern of gelatin displayed bands continuously distributed from 30 to 200 kDa. Amino acid composition analysis test indicated that the content of polar amino acids and the sum of acidic and base amino acids for gelatin were higher than that of BPSC. Studies on gel properties demonstrated that gelatin-collagen mixed solution had collagenlike assembly characteristics and assembly kinetics. The moduli of the assembled gel at 35 oC were equivalent to that of pure bovine tendon collagen system; moreover, the system moduli didn’t change with time with elastic moduli (G') of about 40 Pa. However, at 25 oC, the moduli of gelatin-collagen composite hydrogel increased with the extension of time, its G' increased about 18 times within 8 h, and the ratio of elastic modulus to viscous modulus (G'') increased 4.6 times, showing a significant aging effect of structural strength. Meanwhile, the mechanical strength of the composite hydrogel was also regulated by temperature—the gel was highly elastic (G'≈3,000 Pa, G'>>G'') at a low temperature (5 oC); as the temperature rose, the system moduli gradually decreased and the elastic gel transformed into waterlike fluid at 50 oC little by little. What’s more, gelatin-collagen composite hydrogel also had reversible sol-gel performances and self-healing capability similar to the gelatin hydrogel. This novel preparation method for preparing composite materials and the resultant composite hydrogel are expected to be used in the fields of natural food gels, injectable hydrogels, cell scaffolds, drug sustained-release materials and so on, and improve and promote the processing performances, price and large-scale production of collagen-based materials.
Huang, Zhen,Zhang, Neng,Zha, Lang,Mao, Hong-Chao,Chen, Xuan,Xiang, Ji-Feng,Zhang, Hua,Wang, Zi-Wei Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.2
AMFR, autocrine motility factor receptor, also called gp78, is a cell surface cytokine receptor which has a dual role as an E3 ubiquitin ligase in endoplasmic reticulum-associated degradation. AMFR expression is associated with tumor malignancy. We here investigated the clinical significance of AMFR and its role in metastasis and prognosis in gastric cancer. Expression of AMFR, E-cadherin and N-cadherin in cancer tissues and matched adjacent normal tissues from 122 gastric cancer (GC) patients undergoing surgical resection was assessed by immunohistochemistry. Levels of these molecules in 17 cases selected randomly were also analysed by Western blotting. AMFR expression was significantly increased in gastric cancer tissues, and associated with invasion depth and lymph node metastasis. Kaplan-Meier analysis showed AMFR expression correlated with poor overall survival and an increased risk of recurrence in the GC cases. Cox regression analysis suggested AMFR to be an independent predictor for overall and recurrence-free survival. E-cadherin expression was decreased in gastric cancer tissues; conversely, N-cadherin was increased. Expression of AMFR negatively correlated with E-cadherin expression, whereas N-cadherin expression showed a significant positive correlation with AMFR expression. AMFR might be involved in the regulation of epithelial-mesenchymal transition, with aberrant expression correlating with a poor prognosis and promoting invasion and metastasis in GCs.
Xiujuan Huang,Yan Xiao,Meidong Lang 한국고분자학회 2011 Macromolecular Research Vol.19 No.2
A series of amphiphilic six-armed copolymers, containing poly(ε-caprolactone) (PCL) and poly(2-(diethylamino)ethyl methacrylate) (PDEAEMA or PDEA) as the arm and cyclotriphosphazene as the core, were obtained by a combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). The star block S(PCL-b-PDEAEMA) copolymers were characterized by ^1H NMR spectroscopy and size exclusive chromatography (SEC). These copolymers could self-assembly into micelles in an aqueous solution at low pH with a low critical aggregation concentration (CAC) in the range of 2 to 10 mg/L, which depend on the composition of the copolymers. The original aggregates could further form larger micelles and/or vesicles by adjusting the external stimulus, which was examined by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The lower critical solution temperature (LCST) of the star copolymers were determined to be 49.7 and 26.3 ℃ at pH 6.5and 7.4, respectively, demonstrating a pH-dependent thermo-response.
Xiujuan Huang,Meidong Lang,Yan Xiao 한국고분자학회 2012 Macromolecular Research Vol.20 No.6
A series of star-shaped poly(ε-caprolactone) (PCL)-based diblock and triblock copolymers containing 2-(dimethylamino)ethyl methacrylate (DMAEMA or DMA) and oligo(ethylene glycol)monomethyl ether methacrylate (OEGMA or OEG) were synthesized by one-pot atom transfer radical polymerization (ATRP) using a sixarm PCL-based macroinitiator. The precursor and the resultant copolymers were analyzed via proton nuclear magnetic resonance spectra (1H NMR) and size exclusion chromatography (SEC). The monomer reactivity ratios for DMAEMA (r1) and OEGMA (r2) were estimated to be near unity and r1×r2=1, which indicates the random distribution of the monomers in the final copolymers. Self-assembly behavior of these copolymers was investigated by fluorimetry,1H NMR, dynamic light scattering (DLS), transmission electronic microscopy (TEM), potentiometric titrations, and zeta potential measurements. The results suggested that the star copolymers were responsive to salinity depending on their composition and structure.
Jie Huang,Huajie Hong,Nan Wang,Hongxu Ma,Honglei An,Lin Lang 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.4
The development of hydraulically driven heavy legs that can withstand external interference for realizing the high-velocity dynamic walking of bipedal robots with eight degrees-of-freedom is challenging. Therefore, in this study, a cascade antidisturbance algorithm was proposed for highly dynamic trajectory tracking based on model prediction and task hierarchical optimization. First, in the upper layer, the time-sharing control framework of underactuated robots based on the single rigid body model ignoring the legs was designed. Linear model predictive control (MPC) was designed to calculate the contact force spin to control the posture and height of floating base in the stand phase. The desired foot location principle was used to control the forward and lateral velocity in the swing phase. Next, in the lower layer, task hierarchical optimization control (THOC) was designed to track the contact force spin predicted by MPC. The relaxation variable of the force spin was designed in the optimized variable and subsequently used to compensate for the contact force between single rigid body and whole-body dynamic models. Thus, the tie relationship was developed between the upper MPC and lower THOC. The control robustness of the proposed model under high-velocity locomotion and disturbance was verified by performing simulation experiments investigating high-velocity walking and external impact, and the fast walking velocity was increased from 2.15 m/s of nonlinear MPC to 2.5 m/s with accurate velocity tracking.