Mir Ghasem HOSSEINI*, Mehdi ABDOLMALEKI, Sajjad ASHRAFPOOR
催化学报
doi:10.1016/S1872-2067(11)60464-6
A Ni-Zn binary metal coating was electrochemically deposited on a copper electrode that was coated with nickel (bottom layer). This was then etched in concentrated alkaline solution (30 wt%NaOH) to produce a nanoporous Ni electrocatalytic surface for borohydride electro-oxidation in alkaline solution. The bulk and surface compositions of the coating before and after alkaline leaching were determined by atomic absorption spectroscopy and energy dispersive X-ray analysis. The surface morphology was investigated by scanning electron microscopy. The characterization showed that the leached Ni/Zn-Ni coating has a nanoporous structure. Electrocatalytic activity for boro-hydride electro-oxidation was assessed by cyclic voltammetry and electrochemical impedance spectroscopy. The improved activity of the electrode was related to the removal of corrosion products and the formation of nanopores and cracks during alkaline leaching. Cyclic volt-ammetry studies confirmed that the alkaline leaching process improved the activity of the Ni/Zn-Ni coating in comparison to that of a smooth Ni deposit, and it gave an anodic peak current density that was 21 times higher.
关键词:
Chen Shaoming
,
Gao Manman
,
Zhou Zhiyu
,
Liang Jiabi
,
Gong Ming
,
Dai Xuejun
,
Liang Tangzhao
,
Ye Jiacheng
,
Wu Gang
,
Zou Lijin
,
Wang Yingjun
,
Zou Xuenong
材料科学技术（英文）
doi:10.1016/j.jmst.2016.08.001
Although cartilage tissue engineering has been developed for decades, it is still unclear whether angiogenesis was the accompaniment of chondrogenesis in cartilage regeneration. This study aimed to explore the process of anti-angiogenesis during cartilage regenerative progress in cartilage repair extracellular matrix (ECM) materials under Hypoxia. C3H10T1/2 cell line, seeded as pellet or in ECM materials, was added with chondrogenic medium or DMEM medium for 21 days under hypoxia or normoxia environment. Genes and miRNAs related with chondrogenesis and angiogenesis were detected by RT-qPCR technique on Days 7, 14, and 21. Dual-luciferase report system was used to explore the regulating roles of miRNAs on angiogenesis. Results showed that the chondrogenic medium promotes chondrogenesis both in pellet and ECM materials culture. HIF1α was up-regulated under hypoxia compared with normoxia (P?<?0.05). Meanwhile, hypoxia enhanced chondrogenesis. miR-140-5p exhibited higher expression while miR-146b exhibited lower expression. The chondrogenic phenotype was more stabilized in the ECM materials in chondrogenic medium than DMEM medium, with lower VEGFα expression even under hypoxia. Dual-luciferase report assays demonstrated that miR-140-5p directly targets VEGFα by binding its 3′-UTR. Taken together, chondrogenic cytokines, ECM materials and hypoxia synergistically promoted chondrogenesis and inhibited angiogenesis. miR-140-5p played an important role in this process.
关键词:
Biomaterials
,
Bio-adaptation
,
Hypoxia
,
Chondrogenesis
,
Angiogenesis
,
miRNAs
张鹏鸣
,
孙清
,
SergeiP.Maydanyuk
原子核物理评论
doi:10.11804/NuclPhysRev.34.02.148
讨论了量子多重内部反射方法(MIR方法),这是一种研究核反应的更准确的量子力学方法.对于一个原子核俘获α粒子的过程,MIR方法能够给出(1)α-核势的新参数;(2)新的熔合几率.基于MIR方法我们给出了这类过程的完整量子力学描述,考虑熔合几率后MIR方法能够显著地提高实验与理论的吻合度.具体研究了α+40 Ca和α+44Ca两类反应,给出了新的核势参数核和熔合几率.对于第一个反应理论计算值与实验的偏离比其他计算结果减少了41.72倍,对于第二个反应减少了34.06倍.进一步,基于本工作熔合几率公式,给出了两类反应截面不同的原因,这是与中子幻数N=20附近的原子核基态的球形构型和形变构型共存导致的.为了更好地理解幻数N=26附近原子核的性质,预言了α+46 Ca的反应截面.
关键词:
α粒子俘获
,
隧穿效应
,
多重内部反射方法
,
熔合几率
,
透射系数与反射系数
,
角动量截断
,
α衰变
丁春玲
,
曾国荪
稀有金属
doi:10.3969/j.issn.0258-7076.2005.05.029
研究了不同退火条件下, 新型屏蔽材料钴基非晶态合金Co66Fe4Ni1Si15B14的磁阻抗比(MIR)和磁导率比(PR).采用了两步冷却法(F&W), 通过协同降低内热应力和磁有序, 提高了样品的初始磁导率.研究结果表明, F&W法试样的初始磁导率((i)比单独用熔炉冷却法(FC)和水淬火法(WQ)分别提高了50%和100%.通过测量试样的MIR和PR, 研究了试样软磁性的退火效应, 3.1 MHz下FC法试样和WQ法试样在420 ℃退火温度下具有比F&W法更优越的软磁性.
关键词:
非晶态
,
软磁性
,
磁导率
Bin Tang Yi Yang Youyu Fan Long Zhang
材料科学技术（英文）
The germanate glass ceramics is a potential candidate material for infrared (IR) dome and window applications. The crystallization mechanism of 20BaO-10Ga2O3-70GeO2 glass was investigated by differential thermal analysis (DTA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Two different types of phase evolution were found in the early stage of crystallization: (1) the further growth of the microcrystal formed during the slow cooling of glass melt and (2) the glass-in-glass phase separation. The controlled crystallization was obtained by two-step heat treatment. The middle infrared (MIR)-transparent glass ceramics were obtained, with expected thermal and mechanical improvements.
关键词:
Germanate glass
李守海
,
庄晓伟
,
王春鹏
,
莫亚莉
,
储富祥
材料导报
采用熔融挤出法制备了热塑性橡实淀粉(TPAS)/聚己内酯(PCL)二元复合材料.通过复合材料的拉伸测试、接触角、吸水性、吸湿性、FTIR、SEM、MIR、DMA和土埋实验,研究了PCL含量对复合材料力学性能、疏水性能、热性能和降解性能的影响,结果表明复合材料不仅具有较强的吸水性,还具有优异的力学性能、熔融流动性能和降解性能.
关键词:
橡实淀粉
,
聚己内酯
,
双螺杆挤出机
,
复合材料
,
相容性
