黄土丘陵沟壑区退化生态系统恢复的研究

在对黄土丘陵沟壑区现有主要退化生态系统类型进行科学分类的基础上,以时间序列和空间序列相结合,进行植物群落动态变化及其演替规律的观察和研究,结果表明:退耕地植物群落演替趋势是退耕地→草本入侵→灌木入侵→乔木入侵→乔木群落.     

利用废旧泡沫塑料制备涂料

将废旧泡沫塑料加工改性后，使其由非极性物质转变为半极性物质，以其为原料来制备附着力较好，抗水、抗冻、抗酸、抗碱、抗盐等性能的不同颜色的涂料．对当今社会上越来越多的“白色污染”进行了综合利用，为净化环境起到了不可低估的作用．     

基于强化学习的HP模型优化方法研究

蛋白质结构预测问题一直是生物信息学中的重要问题。基于疏水极性模型的蛋白质二维结构预测问题是一个典型的NP难问题。目前疏水极性模型优化的方法有贪心算法、粒子群算法、遗传算法、蚁群算法和蒙特卡罗模拟方法等，但这些方法成功收敛的鲁棒性不高，容易陷入局部最优。由此提出一种基于强化学习的HP模型优化方法，利用其连续马尔可夫最优决策与最大化全局累计回报的特点，在全状态空间中，构建基于能量函数的奖赏函数，引入刚性重叠检测规则，充分挖掘生物序列中的全局进化关系，从而进行有效与稳定的预测。以3条经典论文序列和5条Uniref50序列为实验对象，与贪心算法和粒子群算法分别进行了鲁棒性、收敛性与运行时间的比较。贪心算法只能在62.5%的序列上进行收敛，该文方法能在5万次训练后稳定的在所有序列上达到了收敛。与粒子群算法相比，两者都能找到最低能量结构，但该文的运行时间较粒子群算法降低了63.9%。     

Pedestrian detection and tracking in infrared imagery using shape and appearance

In this paper, we present an approach toward pedestrian detection and tracking from infrared imagery using joint shape and appearance cues. A layered representation is first introduced and a generalized expectation-maximization (EM) algorithm is developed to separate infrared images into background (still) and foreground (moving) layers regardless of camera panning. In the two-pass scheme of detecting pedestrians from the foreground layer: shape cue is first used to eliminate non-pedestrian moving objects and then appearance cue helps to locate the exact position of pedestrians. Templates with varying sizes are sequentially applied to detect pedestrians at multiple scales to accommodate different camera distances. To facilitate the task of pedestrian tracking, we formulate the problem of shot segmentation and present a graph matching-based tracking algorithm that jointly exploits the shape, appearance and distance information. Experimental results with both OSU Infrared Image Database and WVU Infrared Video Database are reported to demonstrate the accuracy and robustness of our algorithm.     

Pessimists and optimists: Improving collaborative filtering through sentiment analysis

This work presents a novel application of Sentiment Analysis in Recommender Systems by categorizing users according to the average polarity of their comments. These categories are used as attributes in Collaborative Filtering algorithms. To test this solution a new corpus of opinions on movies obtained from the Internet Movie Database (IMDb) has been generated, so both ratings and comments are available. The experiments stress the informative value of comments. By applying Sentiment Analysis approaches some Collaborative Filtering algorithms can be improved in rating prediction tasks. The results indicate that we obtain a more reliable prediction considering only the opinion text (RMSE of 1.868), than when apply similarities over the entire user community (RMSE of 2.134) and sentiment analysis can be advantageous to recommender systems.     

Determination of partition coefficient of migrants in food simulants by the PRV method

Partition coefficients of six migrants between four simulated foods (water, 10% ethanol, 3% acetic acid, 95% ethanol) and air were determined by the phase ratio variation (PRV) method using headspace analyses by gas chromatography. The migrants were ethyl acetate, methyl ethyl ketone, propyl alcohol, butyraldehyde, acetaldehyde and acetonitrile. The results showed that migrant absorption by the four food simulants was highly dependent on the physicochemical properties of migrants and foods, such as polarity, solubility and hydrogen-bonding.     

部分糊化淀粉浆料特性及上浆性能研究

探讨部分糊化淀粉浆液的特性及上浆性能。以示差扫描量热法测定了浆液的糊化程度,用数显黏度计测量了浆液黏度随温度的变化情况,并用莱卡偏光显微镜观察了不同制浆条件下浆液中淀粉颗粒的形貌和偏光性,通过制作浆纱切片观察了浆液在纱线中的分布情况。结果表明:部分糊化淀粉浆液糊化程度对温度很敏感,蒸汽加热至65℃制得的浆液黏度稳定性较高;原淀粉颗粒多呈圆形和多角形,表面光滑,具有明显的偏光十字;发生部分糊化后,淀粉颗粒吸水膨胀,体积变大,颗粒破裂,偏光十字消失;经过部分糊化淀粉室温上浆,棉纱毛羽降低,强力提高,耐磨增加。认为部分糊化淀粉上浆技术利于节能,值得推广。     

Enhanced electricity generation for biocathode microbial fuel cell by in situ microbial-induced reduction of graphene oxide and polarity reversion

A simple effective and environmentally friendly pathway to form graphene modified biocathode was induced by polarity reversion of graphene modified bioanode, which was made by in situ microbial-induced reduction of graphene oxide (GO). Graphene assembled by microbes showed that D/G intensity increased from 0.84 to 0.91 and C/O atomic ratio added from 2.13 to 4.45, indicating GO was reduced largely. The graphene modified biocathode exhibited crumples that grown on the lamellar and glossy surface and was capable of improving catalytic reduction of oxygen. Microbial fuel cell (MFC) fabricated with graphene modified biocathode obtained 1.22 times in maximum power density, 0.21 times in interfacial charge transfer resistance, and recorded an obvious redox peaks at ?0.50 V (vs. SCE) than control biocathode MFC. Geobacter, Clostridium, Pseudomonas, Geothrix and Hydrogenophaga belonged to exoelectrogens occupied 17.53% in graphene modified biocathode, 2.07% in control biocathode in genus level. This study provided a new insight into the feasibility to make microbes self-assembled graphene to improve electrochemical performance of biocathode MFC.     

On the photovoltaic response of the J-domain and the JA-assembly

Photovoltaic devices based on poly-2′,5′-dioctyl-4,4′′-terphenylenecyanovinylene (J-domain) and 4-aza-4-(4′-(poly-2′,5′-dioctyl-4,4′′-terphenylene-1-cyanovinylene-2-yl)biphen-4-yl)-8,12-dioxa-4,8,12,12c-tetrahydrodibenzo[cd,mn]pyrenium tetrafluoroborate (JA-assembly) were prepared using indiumtinoxide (ITO) as the transparent electrode and aluminium as the second electrode. While the photovoltaic response of the J-domain exhibited low short circuit currents of −0.1 nA cm⁻², the corresponding short circuit current of the JA-assembly was observed to be +10 nA cm⁻². The 100-fold increase in magnitude was related to the known energy transfer from the J-domain to the A-domain in the JA-assembly, and the inversion of the sign of the photovoltaic response that implies that the electrodes have a reversed polarity was explained on the basis of the positions of the energy levels and involves the action of the A-domain as a blocking layer and a light operated charge pump that efficiently transfers electrons to the ITO electrode.