基于纳米酶技术检测柑桔果实中葡萄糖

目的 建立纳米酶检测体系快速检测葡萄糖含量的技术.方法 采用甲烷氧化细菌的发酵代谢产物甲烷氧化菌素(methanobactin,MB)与Cu2+、纳米金(AuNPs)、葡萄糖氧化酶(glucose oxidase,Gox)进行配位结合形成具有过氧化物酶和葡萄糖氧化酶性质的纳米酶检测体系,并对柑桔果实中葡萄糖含量进行测定...     

成年和幼龄雪多牦牛肉品质特性研究

目的 研究成年和幼龄雪多牦牛肉品质差异。方法 选择健康的成年和幼龄阉割雪多牦牛, 对其背最长肌常规营养成分、食用肉品质、氨基酸、脂肪酸、维生素和矿物质构成与含量进行分析。结果 成年雪多牦牛肉水分含量为72.89%, 低于幼龄雪多牦牛肉; 成年雪多牦牛肉粗蛋白质、粗脂肪和粗灰分含量分别比幼龄雪多牦牛肉高4.99%、86.67%、38.54%, 因此成年雪多牦牛肉具有更高的营养价值。幼龄雪多牦牛肉食用肉品质极佳, 色泽、口感、嫩度等都优于成年雪多牦牛肉。成年和幼龄雪多牦牛肉都是优质蛋白质来源, 幼龄雪多牦牛肉中必需氨基酸和总氨基酸含量为5.95%和14.00%, 均显著高于成年雪多牦牛肉, 但成年雪多牦牛肉味更鲜美。幼龄雪多牦牛肉的脂肪酸构成略优于成年雪多牦牛肉。在维生素和矿物质组成和含量上, 幼龄雪多牦牛肉的维生素A显著高于成年雪多牦牛肉。成年雪多牦牛肉的碘含量显著高于幼龄雪多牦牛肉。结论 幼龄雪多牦牛肉的脂肪酸和氨基酸构成更加合理健康, 色泽、口感和嫩度更好, 因此幼龄雪多牦牛肉品质比成年雪多牦牛肉好。幼龄雪多牦牛生长周期短, 能够在有限的牧草资源下创造更高的经济价值, 同时可以提高牦牛肉的市场竞争力, 对牧区的牦牛养殖提供科学有效的指导。     

酶提法在元素提取前处理中的应用进展

近年来, 随着对健康的重视及环境保护意识的日益增强, 人们逐渐深入探索食品、药品中元素的总量与形态, 并提出了更为严苛且全面的要求。传统的提取方法虽然在一定程度上能够满足分析的需求, 但往往伴随着各种问题。因此, 探索更为绿色、高效、环保的元素提取技术成为了重中之重。然而, 酶作为一种生物催化剂, 凭借其特异性高、反应条件温和、环境友好等独特优势, 在元素提取领域的应用日益受到重视。酶提法是利用酶的生化作用破坏样品结构, 将其中的大分子断裂为氨基酸, 从而提取出金属元素的一种方法。文章综述了酶在谷类食品、蔬菜、中药、海产品和饲料中元素提取的应用, 并对不同基质适用的酶及酶提法的优缺点进行论述, 以更好地了解酶与不同样品的适配性, 为今后酶提法在不同物质中提取元素总量及形态的应用提供参考。     

In-situ measurement of ethanol tolerance in an operating fuel cell

Ethanol is seen as an attractive option as a fuel for direct ethanol fuel cells and as a source for on-demand production of hydrogen in portable applications. While the effect of ethanol on in-situ electrode behavior has been studied previously, these efforts have mostly been limited to qualitative analysis. In alkaline fuel cells, several cathode catalysts, including Pt, Cu triazole, and Ag can be used. Here, we apply a methodology using a microfluidic fuel cell to analyze in-situ the performance of these cathodes as well as Pt anodes in the presence of ethanol and acetic acid, a common side product from ethanol oxidation. For a given concentration of ethanol (or acetic acid), the best cathode catalyst can be determined and the kinetic losses due to the presence of ethanol (or acetic acid) can be quantified. These experiments also yield information about power density losses from the presence of contaminants such as ethanol or acetic acid in an alkaline fuel cell. The methodology demonstrated in these experiments will enable in-situ screening of new cathodes with respect to contaminant tolerance and determining optimal operational conditions for alkaline ethanol fuel cells.     

Amorphous silicon nanocone array solar cell

ABSTRACT: In the hydrogenated amorphous silicon [a-Si:H]-thin film solar cell, large amounts of traps reduce the carrier's lifetime that limit the photovoltaic performance, especially the power conversion efficiency. The nanowire structure is proposed to solve the low efficiency problem. In this work, we propose an amorphous silicon [a-Si]-solar cell with a nanocone array structure were implemented by reactive-ion etching through a polystyrene nanosphere template. The amorphous-Si nanocone exhibits absorption coefficient around 5 × 105/cm which is similar to the planar a-Si:H layer in our study. The nanostructure could provide the efficient carrier collection. Owing to the better carrier collection efficiency, efficiency of a-Si solar cell was increased from 1.43% to 1.77% by adding the nanocone structure which has 24% enhancement. Further passivation of the a-Si:H surface by hydrogen plasma treatment and an additional 10-nm intrinsic-a-Si:H layer, the efficiency could further increase to 2.2%, which is 54% enhanced as compared to the planar solar cell. The input-photon-to-current conversion efficiency spectrum indicates the efficient carrier collection from 300 to 800 nm of incident light.     

Improving the Long Lead-Time Inundation Forecasts Using Effective Typhoon Characteristics

In this paper, a new type of inundation forecasting model with the effective typhoon characteristics is proposed by integrating support vector machine (SVM) with multi-objective genetic algorithm (MOGA). Firstly, a comparison of the proposed model and an existing model based on back-propagation network (BPN) is made to highlight the improvement in forecasting performance. Next, the proposed model is compared with the SVM-based model without typhoon characteristics to investigate the influence of typhoon characteristics on inundation forecasting. Effective typhoon characteristics for improving forecasting performance are identified as well. An application to Chiayi City, Taiwan, is conducted to demonstrate the superiority of the proposed model. The results confirm that the proposed model with the effective typhoon characteristics does improve the forecasting performance and the improvement increases with increasing lead-time, especially for long lead-time forecasting. The proposed model is capable of optimizing the input to decrease the negative impact when increasing forecast lead time. In conclusion, effective typhoon characteristics are recommended as key inputs for inundation forecasting during typhoons.     

E-auction web assessment model in China

Electronic auction (e-auction), a major e-commerce model, has enjoyed rapid growth in many countries. This study develops a web assessment model (EAWAM) from a consumer perspective that suggests that user intention to continue using an e-auction website is based on users’ satisfaction with the e-auction website, which is determined by perceived e-auction user friendliness, functionality and interactivity. Web trustworthiness serves as an important antecedent to perceived e-auction user friendliness and functionality. To validate this model, a survey was conducted using 191 users of Taobao.com from 15 cities in China. Partial Least Square analysis results provided strong support for this model and also yielded important implications and suggestions for further research.     

Assessment of Effective Monitoring Sites in a Reservoir Watershed by Support Vector Machine Coupled with Multi-Objective Genetic Algorithm for Sediment Flux Prediction during Typhoons

Water Resources Management - Effectively assessing crucial monitoring sites with suspended sediment concentration (SSC) is a vital challenge for achieving accurate prediction of sediment flux on...     

一种复杂背景图像文字分割算法

根据图像中文字与背景区域的形态特征,提出了一种基于形态运算和连通元分析的复杂背景图像文字分割算法.实验结果表明,即使在图像分辨率不高以及文字布局较复杂的情况下,该算法仍然较快较准确地定位和分割出复杂背景图像中的文字.     

融合关节旋转特征和指尖距离特征的手势识别

作为人机交互的重要方式,手势交互和识别由于其具有的高自由度而成为计算机图形学、虚拟现实与人机交互等领域的研究热点.传统直接提取手势轮廓或手部关节点位置信息的手势识别方法,其提取的特征通常难以准确表示手势之间的区别.针对手势识别中不同手势具有的高自由度以及由于手势图像分辨率低、背景杂乱、手被遮挡、手指形状尺寸不同、个体差异性导致手势特征表示不准确等问题,本文提出了一种新的融合关节旋转特征和指尖距离特征的手势特征表示与手势识别方法.首先从手势深度图中利用手部模板并将手部看成链段结构提取手部20个关节点的3D位置信息;然后利用手部关节点位置信息提取四元数关节旋转特征和指尖距离特征,该表示构成了手势特征的内在表示;最后利用一对一支持向量机对手势进行有效识别分类.本文不仅提出了一种新的手势特征表示与提取方法,该表示融合了关节旋转信息和指尖距离特征;而且从理论上证明了该特征表示能唯一地表征手势关节点的位置信息;同时提出了基于一对一SVM多分类策略进行手势分类与识别.对ASTAR静态手势深度图数据集中8类中国数字手势和21类美国字母手势数据集分别进行了实验验证,其分类识别准确率分别为99.71%和85.24%.实验结果表明,本文提出的基于关节旋转特征和指尖距离特征的融合特征能很好地表示不同手势的几何特征,能准确地表征静态手势并进行手势识别.