Evaluation of peach quality indices using an electronic nose by MLR, QPST and BP network

In this paper, responses of a gas sensor array were employed to establish a quality indices model evaluating the peach quality indices. The relationship between sensor signals and the firmness, the content of sugar (CS) and acidity of “Dabai” peach were developed using multiple linear regressions with stepwise procedure, quadratic polynomial step regression (QPST) and back-propagation network. The results showed that the multiple linear regression model represented good ability in predicting of quality indices, with high correlation coefficients (R² = 0.87 for penetrating force CF; R² = 0.79 for content of sugar CS; R² = 0.81 for pH) and relatively low average percent errors (ERR) (9.66%, 7.68% and 3.6% for CF, CS and pH, respectively). The quadratic polynomial step regression provides an accurate quality indices model, with high correlation (R² = 0.92, 0.87, 0.83 for CF, CS and pH, respectively) between predicted and measured values and a relatively low error (5.47%, 3.45%, 2.57% for CF, CS and pH, respectively) for prediction. The feed-forward neural network also provides an accurate quality indices model with a high correlation (R² = 0.90, 0.81, 0.87 for CF, CS and pH, respectively) between predicted and measured values and a relatively low average percent error (6.39%, 6.21%, 3.13% for CF, CS and pH, respectively) for prediction. These results prove that the electronic nose has the potential of becoming a reliable instrument to assess the peach quality indices.     

基于多目标满意优化的交通信号控制

随着城市道路交通供需矛盾的不断突出,交通信号控制策略、控制方法的科学合理性成为影响城市交通性能的关键因素。分析了传统最优交通控制理论的不足,揭示了交通控制中的满意性准则;建立了道路交叉口的满意交通控制模型,并结合某示范工程项目进行了试用。应用结果表明,模型科学、合理、有效,采用该模型的区域道路交通状况明显改善,对于缓解城市交通拥挤有一定帮助。     

电厂煤粉炉联产水泥熟料技术试验研究

以低硫兖州煤和高硫长广煤为试验煤种,在两段多相试验台开展了煤粉炉联产水泥熟料技术试验研究.试验结果表明:低硫兖州煤和高硫长广煤联产水泥熟料试验样品的固硫率均在50%左右,高于煤粉炉仅为30%的炉内喷钙脱硫效率,样品熟料矿物与普通水泥熟料矿物组成相似、性能相近.通过对样品熟料矿物的特征分析,提出了开展电厂煤粉炉联产水泥熟料技术研究的重点.     

基于小波包分解和支持向量机的石油套管缺陷智能识别

 针对石油套管缺陷超声无损检测(NDT)中缺陷回波的特点,提出了一种基于小波包分解和支持向量机(SVM)的缺陷智能识别新方法。分析了Gabor、小波和小波包3种信号时频变换分解方法的特点,并进行了基于3种方法生成的特征数据可分性比较,确定了小波包分解方法效果最好。根据SVM解决分类问题的原理,采用SVM法对3种时频分解提取的缺陷信号特征数据进行识别。试验表明,基于小波包分解局部熵的特征提取结合SVM模式智能识别的组合方法,可应用于石油套管上的4种典型缺陷的识别。     

电子鼻/舌融合技术的信阳毛尖茶品质检测

为实现茶叶品质和化学成分快速鉴别和预测,采用电子鼻与电子舌联用技术对信阳毛尖茶茶叶挥发性气味和茶汤滋味成分进行检测分析。对电子鼻与电子舌联用的响应值进行主成分分析,结果显示电子鼻与电子舌数据融合可提高对茶叶样品区分度。通过电子鼻与电子舌响应的融合数据,对茶叶样品中茶多酚、咖啡碱含量建立预测模型。结果表明,多元线性回归、多元线性逐步回归、二次多项式逐步回归模型中回归系数效果显著（P＜0.01）,其中二次多项式逐步回归模型效果最佳,茶多酚建模集和验证集的决定系数分别为0.999、0.975,均方根误差分别为0.083、0.174;咖啡碱建模集和验证集的决定系数分别为0.985、0.978,均方根误差分别为0.015、0.048。电子鼻/舌联用可对茶叶品质和理化成分进行很好地分析和预测。     

光合细菌制氢试验装置及其技术研究进展

综述了太阳能光合细菌制氢试验装置及其技术研究现状,通过分析太阳能光合细菌制氢试验装置的内置光源、多点分散布光、自然光源为主光源并辅以人工冷光源、改造反应装置内部结构、反应装置光源部分可拆装等技术途径,提出了太阳能光合细菌制氢试验装置的发展方向,为太阳能光合细菌连续制氢装置优化设计提供科学参考。     

Design of novel pentagonal 2D transitional-metal sulphide monolayers for hydrogen evolution reaction

Due to the unique properties and diverse applications, two-dimensional (2D) nanomaterials have been widely investigated in these years. In this work, a group of new pentagonal 2D transitional-metal sulphide monolayers (MS, M = Fe, Mn, and V) are designed based on density-functional-theory (DFT) calculations. We show that all three monolayer structures are thermally, dynamically and mechanically stable. We find that FeS, MnS and VS are metallic, and FeS and MnS are also magnetic, in which the magnetic moments are contributed by the Fe and Mn atoms, respectively. We further find that these MS monolayers show high activities for hydrogen evolution reactions (HER) as the calculated Gibbs free energies are close to zero electron volt (eV), especially for FeS and VS. Our findings broaden the family of noble-metal-free two-dimensional materials, and also help to develop low cost commercial HER catalysts.     

MxOy (M = Mg,Zr, La,Ce) modified Ni/CaO dual functional materials for combined CO2 capture and hydrogenation

The integrated CO₂ capture and utilization has recently attracted attention as a promising approach to reduce CO₂ emissions as well as produce value-added chemicals and fuels. Herein, metal oxides (M_xO_y, M = Mg, Zr, La, and Ce) modified Ni/CaO dual functional materials (M-Ni/Ca DFMs) were synthesized and applied to the combined CO₂ capture and hydrogenation using a single reactor at one temperature. The La–Ni/Ca showed the highest CO₂ adsorption capacity (13.8 mmol/g), CO₂ conversion (64.3%) and CO yield (8.7 mmol/g). Results indicated that the addition of metal oxides increased the number of basic sites which played important role in efficient CO₂ capture. The high activities of M-Ni/Ca were attributed to the formation of highly dispersed small-sized Ni particles. Furthermore, the La–Ni/Ca exhibited excellent cyclic stability after 20 cycles due to the La₂O₃ as a physical barrier and a support for inhibiting the growth and sintering of CaO and Ni particles.     

Numerical simulation of the interaction and coalescence of inline hydrogen bubbles in biohydrogen production by photofermentation with corncob

The escape rate of hydrogen in photobiological hydrogen production plays an important role in the biochemical reaction process, and the interaction of hydrogen bubbles in bio-hydrogen production material liquid affects the escape rate of hydrogen. In this paper, the Eulerian-Eulerian-Multifluid VOF method is used to simulate the interactions of three types of hydrogen bubbles: coalescence of equal-sized inline hydrogen bubbles, a small leading hydrogen bubble is chased by a large trailing hydrogen bubble and a large leading hydrogen bubble is chased by a small trailing hydrogen bubble. The results show that the interaction strength between hydrogen bubbles is influenced by the initial interval and initial diameter of the hydrogen bubbles and the flow index of the hydrogen-producing material liquid. The hydrogen bubbles exhibit three types of aggregation. In the pre-merger period, the velocity of the trailing hydrogen bubble also shows four stage changes, which are acceleration to the maximum velocity - deceleration - small increase in velocity - deceleration to the merging velocity. There is also a brief acceleration of the leading hydrogen bubble. For the interaction between Type II and Type III hydrogen bubbles of the same size, there is no significant difference in the rise rate of large hydrogen bubbles after the coalescence.