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Fabrication of shish-kebab-structured carbon nanotube/poly(ε-caprolactone) composite nanofibers for potential tissue engineering applications

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Rare Metals 2019年第1期38卷 64-72页

作者： Tong Wu Xin Chen Jin Sha yi-yan peng Yu-Lu Ma Lin-Sheng Xie Lih-Sheng Turng Engineering Center of Efficient Green Process Equipment and Energy Conservation Ministry of Education East China University of Science and Technology School of Mechanical and Power Engineering East China University of Science and Technology Wisconsin Institute for Discovery University of Wisconsin-Madison

The electrospinning process was applied to fabricate the nanofibers of biodegradable poly(ε-caprolactone)(PCL) in which different contents of multiwalled carbon nanotubes(MWCNTs) were embedded. Afterward,the electrospun nanofibers were successfully decorated with shish-kebab structure via a self-induced crystallization technique. The topographical features and the mechanical properties of the composite scaffolds were characterized,and the biocompatibility of the material was assessed by using human osteogenic sarcoma osteoblasts(MG-63 cells). The carbon nanotube(CNT) concentration is found to affect the fiber diameter and mechanical properties of electrospun nanofibers and the periodic distance of the shish-kebab architecture. Cellular attachment and proliferation assays reveal that 0.5 wt% CNT-embedded PCL scaffold shows enhanced biocompatibility with MG-63 cells than their counterparts made of neat PCL, and the collagen-like nanotopology provided by the shish-kebab structure further facilitates the cell adhesion and proliferation. The superior interactions between cells and scaffolds demonstrate that the shish-kebab-structured CNTs/PCL nanofibers may be promising candidate for tissue engineering scaffold application.

关键词： Carbon nanotubes Poly(ε-caprolactone) Electrospinning Shish-kebab structure Tissue engineering

Kinetic studies of the decomposition reaction of adducts of dinuclear Fe(Ⅱ)/O_2

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Chinese Science Bulletin 2002年第6期47卷 461-463页

作者： peng yi, yan Shiping, CHENG peng,LIAO Daizheng, JIANG Zonghui & WANG GenglinDepartment of Chemistry, Nankai University, Tianjin 300071, China Department of Chemistry Nankai University Tianjin China

Kinetic studies of the decomposition reaction of dinuclear Fe(Ⅱ) adducts [Fe2(N-Et-HPTB){O2P(OPh)2}](Cl-O4)2(1) and [Fe2(N-Et-HPTB) {O2P(Ph)2}] (C1O4)2 (2) with O2 have been carried out at low temperature using UV-vis spectra. The decomposition reaction of Fe(Ⅱ)/O2 adducts was first-order in the experimental conditions, and the activation parameters were obtained. △H≠ = 85.62kJ·mol-1, △S≠ =19.43 J·mol-1·K-1 for compound (1) and △H≠=97.97 kJ·mol-1, △S≠ = 55.68 J·mol-1·K-1 for compound (2). These results are similar to those of dioxygen adducts of other metals complexes and natural enzymes such as methane mono-oxygenase (MMOH).

关键词： dinuclear iron complex activation of O2 kinetics mo-deling system.

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退火对注射成型PC制品力学性能的影响

化工学报 2010年第6期61卷 1555-1559页

作者：王鑫 yi-yan peng 李海梅申长雨郑州大学橡塑模具国家工程研究中心河南郑州450002 Engineering Polymer Center University of Wisconsin-Madison WI 53706 USA

注射成型的塑料光学制品应用日益广泛,但注射成型加工的聚碳酸酯制品通常有较大的残余应力,会对制品的光学性能、力学性能有负面的影响,而退火可减少/消除制品的残余应力。本文考察了退火对不同工艺条件下注射制品残余应力和力学性能的... 详细信息

注射成型的塑料光学制品应用日益广泛,但注射成型加工的聚碳酸酯制品通常有较大的残余应力,会对制品的光学性能、力学性能有负面的影响,而退火可减少/消除制品的残余应力。本文考察了退火对不同工艺条件下注射制品残余应力和力学性能的影响。研究的工艺条件包括三水平的变化的模具温度、熔体温度、保压压力、冷却时间等;残余应力的变化通过光弹实验的应力干涉条纹表示,力学性能的变化以拉伸强度、延伸率的变化表示。实验发现,退火前后,不同工艺条件下注塑PC制品拉伸强度平均提高4.5%,最大达9.0%;同时,断裂延伸率平均降低3%,最多减少14%。

关键词：退火注射成型拉伸强度延伸率

Thermal and mechanical behavior of casting copper alloy wheel during wheel and belt continuous casting process

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China Foundry 2024年第1期21卷 82-90页

作者： Kun Gao yan peng School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004HebeiChina

To investigate the thermal and mechanical behavior of casting wheel,a two-dimensional thermoelastic-plastic finite element model was used to predict the temperature,stress and distortion distribution of the casting wheel during the wheel and belt continuous casting *** effects of grinding thickness and casting speed on the thermal and mechanical behaviors of the center of the hot face of the casting wheel were discussed in *** each rotation,the casting wheel passes through four different spray *** results show that the temperature distribution of the casting wheel in different spray zones is similar,the temperature of the hot face is the highest and the temperature reaches the peak in the spray zoneⅢ.The stress and distortion depend on the temperature distribution,and the maximum stress and distortion of the hot face are 358.2 MPa and 1.82 mm,*** temperature at the center of the hot face decreases with increasing grinding thickness and increases with increasing casting speed.

关键词： casting wheel finite element model grinding thickness casting speed hot face spray zones

Numerical simulation of fluid flow and free surface fluctuations during wheel and belt casting process

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Journal of Iron and Steel Research International 2024年第5期31卷 1117-1126页

作者： Kun Gao yan peng National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao066004HebeiChina

The unstable fluid flow and severe free surface fluctuations in the wheel and belt caster can affect the quality of the cast *** lower level height tends to entrap inclusions in the molten *** the other hand,the higher level height makes the production process more dangerous due to the overflow of high temperature fluid from the mold.A computational model of the molten metal pouring process was *** transient fluid flow and free surface fluctuations behavior were calculated using the three-dimensional large eddy simulation model and the volume of fluid *** results show that the flow velocity of the main jet gradually decreases under the influence of the low kinetic energy fluid in the *** is an obvious oscillation in the tail of the jet,while the flow field is asymmetric in *** jet is closer to the inside radius side due to the Coanda effect,and there is a recirculation zone on the inside radius and the outside radius respectively,according to the 10 s time-averaged *** with the industrial observation and simulation results,the shape of the free surface is a wave that varies with *** addition,the free surface height is lowest and the flow velocity is highest in the region near the jet.

关键词： Fluid flow Free surface Wheel and belt caster Large eddy simulation Volume of fluid method

Effects of pre-moxibustion at Zusanli (ST36) on heat shock protein 70 expression in rats with gastric mucosal lesions after neurotomy

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Neural Regeneration Research 2012年第30期7卷 2370-2376页

作者： Liang peng Mi Liu Xiaorong Chang Zhou yang Shouxiang yi Jie yan yan peng College of Acupuncture and Tuina Hunan University of Chinese Medicine Changsha 410007 Hunan Province China

Studies have shown that pre-moxibustion protects the gastric mucosa by up-regulating the expression of heat shock protein 70. However, the signaling pathway underlying this effect remains unclear. Rats were intragastrically administered absolute alcohol, causing obvious lesion of the gastric mucosa. Following pre-moxibustion at Zusanfi （ST36） for 8 days, the ulcer index decreased to different degrees. The results of an enzyme linked immunosorbent assay and western blotting showed significant upregulation of heat shock protein 70 expression in the gastric mucosa and serum. None out of transection of the spinal cord, damage to the nucleus of the solitary tract, neurotomy of the vagal nerve and neurotomy of the common peroneal nerve affected the decrease in ulcer index or the increase in heat shock protein 70 expression in serum after pre-moxibustion at Zusanfi, and heat shock protein 70 expression was obviously decreased in the gastric mucosa. These findings suggest that pre-moxibustion at Zusanfi can protect the gastric mucosa against lesioning, and that the mechanism underlying this effect involves its induction of heat shock protein 70 expression. Neural pathways participate in the regulatory effects of moxibustion on heat shock protein 70 expression in the gastric mucosa.

关键词： pre-moxibustion transection of neural pathway Zusanli (ST36) gastric mucosal lesion heat shockproteins-70 ulcer index traditional Chinese medicine neural regeneration

Effect of pre-moxibustion on apoptosis and proliferation of gastric mucosa cells

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World Journal of Gastroenterology 2007年第15期13卷 2174-2178页

作者： Shou-Xiang yi yan peng Xiao-Rong Chang Na peng Jie yan Yap-Ping Lin The Institute of Acupuncture Moxibustion and Massage Hunan University of Traditional Chinese Medicine Changsha 410007 Hunan Province China

AIM： TO observe the effects of pre-moxibustion on apoptosis and proliferation of gastric mucosal cell in rats with stress-induced ulcer, and to analyze the relationship between those effects and the expression of heat-shock protein 70 （HSP70）. METHODS： Sixty healthy Sprague Dawley rats were randomly assigned into four groups, namely group A, B, C and D. The animal model of stress ulcer was established by water immersion and restraint stress. The rats in group A, B, and D served as the restraint, model, and non-acupoint controls, respectively, while those in group C received moxibustion at Zusanli and Uangmen points. Immunohistochemical methodology was used to detect the expression of HSP70, apoptosis index （AI, × 10^-6/μm^2） and proliferation index （PCNA-LI, × 10^-6/μm^2）. The mucosal expression of transforming growth factor α （TGF-α） was detected by radioimmunoassay. RESULTS： IVloxibustion at Zusanli and Liangmen points significantly decreased the gastric injury and the apoptosis of gastric mucosal cells, while markedly increased the mucosal expression of TGF-α and HSP70 as well as the proliferation of gastric mucosal cells. Compared with group A, ulcer index （UI）（26.8 ± 9.8 vs 12.0 ± 5.9, P 〈 0.01）, AI （9.6 ± 4.2 vs 4.4 ± 2.6, P 〈 0.05） and expression of HSP70 （9.6 ± 4.2 vs 4.4 ± 2.6, P 〈 0.05） were significantly increased, but the content of TGF-α （104.7 ± 51.2 pg/mL vs 254.0 ± 86.9 pg/mL, P 〈 0.01） and PCNA-LI （6.9 ± 4.7 vs 14.9 ± 4.6, P 〈 0.05） were significantly decreased in group B. However, ulcer index values （UI） and AI were obviously lower in group C compared to groups B and D （14.1 ± 5.4 vs 26.8 ± 9.8 and 26.2 ± 7.7, P 〈 0.01, 3.0 ± 1.6 vs 9.6 ± 4.2 and 8.2 ± 5.2, P 〈0.05, respectively）, but content of TGF-α （237.0 ± 72.6 pg/mL vs 104.7 ± 51.2 pg/mL and 154.1 ± 61.3 pg/mL, P 〈0.01） and expression of HSP70 （0.13 ± 0.03 vs 0.08 ± 0.06 and 0.06 ± 0.04, P 〈 0.05） were higher in group C. Furthermore, the PCNA-LI was significantly higher in group C than in

关键词： Moxibustion Stress ulcer HSP70 Proliferating cell nuclear antigen Apoptosis

Optimal Cooperative Secondary Control for Islanded DC Microgrids via a Fully Actuated Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 405-417页

作者： yi Yu Guo-Ping Liu yi Huang peng Shi IEEE Shenzhen Key Laboratory of Control Theory and Intelligent Systems Southern University of Science and TechnologyShenzhen 518055China School of Electrical Engineering and Automation Wuhan UniversityWuhan 430072China School of Electrical and Mechanical Engineering the University of AdelaideSA 5005Australia Research and Innovation Centre Obuda University1034 BudapestHungary

DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately portray the electrical characteristics of actual MGs while is controller design-friendly has kept the issue active. To this end, this paper establishes a large-signal model containing the comprehensive dynamical behavior of the DC MGs based on the theory of high-order fully actuated systems, and proposes distributed optimal control based on this. The proposed secondary control method can achieve the two goals of voltage recovery and current sharing for multi-bus DC MGs. Additionally, the simple structure of the proposed approach is similar to one based on droop control, which allows this control technique to be easily implemented in a variety of modern microgrids with different configurations. In contrast to existing studies, the process of controller design in this paper is closely tied to the actual dynamics of the MGs. It is a prominent feature that enables engineers to customize the performance metrics of the system. In addition, the analysis of the stability of the closed-loop DC microgrid system, as well as the optimality and consensus of current sharing are given. Finally, a scaled-down solar and battery-based microgrid prototype with maximum power point tracking controller is developed in the laboratory to experimentally test the efficacy of the proposed control method.

关键词： DC microgrids distributed control high-order fully actuated system approach linear quadratic regulator microgrid modeling secondary control

Simple preparation of C(CS)/g-C_(3)N_(4)/Co carbon aerogel and its catalytic performance for ammonium perchlorate

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Defence Technology（防务技术） 2024年第3期33卷 186-196页

作者： Yujie yan Bo Jin Rufang peng State Key Laboratory of Environment-friendly Energy Materials School of Materials Science and EngineeringSouthwest University of Science and TechnologyMianyang621010China

Biomass chitosan(CS)was used as a template,graphitic phase carbon nitride(g-C_(3)N_(4))with high nitrogen content and certain catalytic activity was used as a dopant,and nano-transition metal cobalt(Co)was used as a catalytic center *** carbon aerogel(C(CS)/g-C_(3)N_(4)/Co)with a three-dimensional network-like structure was prepared by assembling the three materials through experimental operations such as freeze-drying and high-temperature *** was demonstrated by scanning and transmission characterization that the CS in the carbon aerogel could provide more active sites for the cobalt nanoparticles,and the doping of graphite-phase carbon nitride as a template dispersed the cobalt nanoparticles and changed the conductivity of the *** investigate the catalytic effect of carbon aerogel on ammonium perchlorate(AP),it was investigated by differential thermal analyzer and TG thermal *** carbon aerogel was very effective in catalyzing AP,and the 10 wt% content of the catalyst reduced the AP pyrolysis peak from 703.9 to 595.5 *** to further investigate the synergistic effect of the three materials,further carbon aerogels such as C(CS)/Co,g-C_(3)N_(4)/Co were prepared and applied to catalyze AP,and the same ratio reduced the AP pyrolysis peak by 98.1℃ and 97.7℃.This result indicates a synergistic effect of the assembly of the three materials.

关键词： g-C_(3)N_(4) Chitosan Co Ammonium perchlorate Pyrolysis kinetics