Electrochemical and spectroscopic characterization of a Benzo[c]cinnoline electrografted platinum surface

In this work, a platinum surface was modified with benzo[c]cinnoline (BCC) to get new insight into the metal modification area. By potential scanning from + 0.4 V to - 0.8 V, the diazotized BCC was reduced electrochemically and grafted onto the platinum electrode surface to form benzo[c]cinnoline modified platinum electrode (Pt-BCC). Electrochemical reduction of benzo[c]cinnoline diazonium salt on the electrode surface yielded a relatively stable organic film. The introduction of BCC molecules onto the platinum surface was verified by cyclic voltammetry, electrochemical impedance spectroscopy, Raman spectroscopy and ellipsometry. The stability and the potential range of the Pt-BCC electrode were also studied.     

改性木素磺酸盐泵送剂GCL1-3的制备及性能研究

通过研究缓凝高效减水剂GCL1与保水剂、引气剂的配伍性能 ,研制了混凝土泵送剂GCL1- 3。GCL1与保水剂HEC、引气剂复配时 ,改善了水泥净浆的保水性能 ,提高了硬化水泥的早期及后期抗压强度。实验测试了GCL1- 3的水泥净浆流动度、减水率、流动度损失和抗压强度等性能。结果表明 ,当w (水 )∶w(水泥 ) =0 4∶1 0 ,w (GCL1- 3) =0 .5 %时 ,水泥净浆流动度可达2 30mm ,减水率达 18% ,且无离析现象 ;2h内流动度损失仅为 2 4% ,而掺FDN的净浆已经失去流动性 ;w(GCL1- 3) =0 .5 %时 ,水泥净浆硬化 3d、7d、2 8d的抗压强度比分别达 146 %、15 8%与148% ,均高于使用FDN     

Statistical characterization of acceleration levels of random vibrations during transport

Random vibration tests are an efficient way to simulate the mechanical vibratory effects caused by transportation. The usual method is only concerned with the frequency distribution pattern of the signal using the average power spectral density. This work offers an additional method based on detailed analysis of instantaneous acceleration levels of a real road transport, which enables modelling of the statistical distribution of these levels. Continuous recording of acceleration signal all along the journey permits confirmation that this statistical distribution is not a Gaussian distribution but a modified Gaussian distribution, for which parameters are estimated and discussed. Therefore, it is possible to evaluate the transport severity by working out the appearance probability of acceleration levels greater than a fixed threshold and also the statistical moments, i.e. second order moment which gives the root mean square value together with fourth order moment (kurtosis) which evaluates the difference between the experimental distribution and the Gaussian distribution. Copyright © 2011 John Wiley & Sons, Ltd.     

Optimization of PEMFC model parameters with a modified particle swarm optimization

In this paper, an electrochemical‐based proton exchange membrane fuel cell (PEMFC) model suitable for engineering applications is presented. In order to improve the accuracy of this model so that it can reflect the actual PEMFC performance better, its parameters are optimized by means of a modified particle swarm optimization (MPSO). The MPSO is a modified method for the PSO's inertia weight. The proposed inertia weight is calculated according to the distance of the particle's current position from the best solution of the entire swarm. The obtained results of the PEMFC model with optimized parameters agree with experimental data well. Therefore, the MPSO is a helpful and reliable technique for optimizing the model parameters and can be used to solve other complex parameter optimization problems of fuel cell models. Copyright © 2010 John Wiley & Sons, Ltd.     

精锻齿坯在辊底式保护气氛连续炉中的球化退火

精锻齿坯的球化退火是精锻齿轮的关键工序之一。齿坯在创新的辊底式保护气氛连续退火炉中球化退火时,无氧化无脱碳,退火组织理想,取得了满意的质量效果,而且节电、省材、环保,生产成本低,具有显著的社会和经济效益。     

一种改性石油磺酸钠的合成与表征

以大庆炼化公司的渣油-糠醛抽出油为原料，通过付-克反应、knoevenagcl反应和磺化反应，合成了一种改性石油磺酸钠（PCS）。对产物进行了表征及性能测试，并与普通石油磺酸钠性能进行比较。     

Cellular Response of Limbal Stem Cells on Poly (Hydroxybuthyrate-co-Hydroxyvalerate) Porous Scaffolds for Ocular Surface Bioengineering

The aim of this study was to develop a modified-porous poly (3-hydroxybutyrate-co-3- hydroxyvalerate) (PHBV) scaffold for limbal stem cell (LSC) expansion that can serve as a potential alternative substrate to replace human amniotic membrane. The human limbal stem cell was used to evaluate the biocompatibility of substrates (porous scaffold, human amniotic membrane and thermoresponsive substrate) based on their viability, proliferation, and attachment ability. Biocompatibility results indicated that the all substrates were highly biocompatible, as LSCs could favorably attach and proliferate on the scaffold surface. Microscopic figures showed that the human limbal stem cell was firmly anchored to the substrates and were able to retain a normal corneal stem cell phenotype. Microscopic analyses illustrated that cells infiltrated the porous scaffold and successfully formed a three-dimensional corneal epithelium, which was viable for two weeks. Gene expression results revealed no change in the expression profile of LECs grown on scaffold when compared to those grown on human amniotic membrane or thermo responsive substrate. In addition, porous PHBV substrate provides not only a milieu supporting LSCs expansion, but also serve as a useful alternative carrier for ocular surface tissue engineering and could be used as an alternative substrate to amniotic membrane.     

Controlled and modified atmospheres influence chilling injury,fruit quality and antioxidative system of Japanese plums (Prunus salicina Lindell)

Our objective was to compare the effects of controlled atmosphere (CA) and modified atmosphere packaging (MAP) on fruit quality, chilling injury (CI) and pro‐ and antioxidative systems in ‘Blackamber’ Japanese plums. Matured fruit were stored for 5 and 8 weeks at 0–1 °C in normal air, CA‐1 (1% O₂ + 3% CO₂), CA‐2 (2.5% O₂ + 3% CO₂) and MAP (~10% O₂ and 3.8% CO₂). CA was more effective than MAP in retention of flesh firmness and titratable acidity during cold storage. Fruit stored in CA‐1 showed reduced CI and membrane lipid peroxidation after 5 and 8 weeks of cold storage. Low O₂ atmospheres appeared to limit the generation of reactive oxygen species (ROS) and their efficient scavenging through the concerted action of superoxide dismutase and peroxidase. The role of ascorbate–glutathione (AsA–GSH) cycle in the regulation of oxidative stress was also studied during and after storage in different atmospheres. In conclusion, optimum CA conditions delayed fruit ripening and CI through augmentation of antioxidative metabolism and suppression of oxidative processes.