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食用蔬菜能吸收和积累微塑料 期刊论文 OAI收割
科学通报, 2019, 卷号: 64, 期号: 9, 页码: 928-934
作者: 李连祯; 周倩; 尹娜; 涂晨; 骆永明

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收藏 | 浏览/下载：146/0 | 提交时间：2020/06/17

微塑料生菜聚苯乙烯微球吸收积累健康风险 microplastics lettuce polystyrene microbeads uptake accumulation human health risk Microplastic (MP, 100 nm-5 mm) may present an attributable risk to ecosystem and human health, and its pollution has become a global environmental concern. Despite a wealth of information on the accumulation of MPs in aquatic species, there is no information on the uptake and accumulation of MPs by higher plants. Terrestrial edible plants are directly exposed to MPs when agricultural soil was applied with organic manure, sewage sludge as fertilizer or plastic mulching. In this paper, the uptake of two sizes of polystyrene (PS) microbeads (0.2 and 1.0 mum) and then their distribution and migration in an edible plant lettuce were firstly investigated based on laboratory experiments. We used fluorescent markers to track PS microbeads in plant tissues and found fluorescence to be a sensitive and reliable detection method. Sections from untreated control lettuce showed no autofluorescence. When roots were treated with fluorescently labeled PS microbeads, the microbeads could be identified by its fluorescence. Our main study investigated the uptake of 0.2 mum beads, as few luminescence signals were observed in lettuce roots for 1.0 mum beads in our experiment. We observed that 0.2 mum fluorescent microbeads were extracellularly trapped in the root cap mucilage (which is a highly hydrated polysaccharide) and a dark green tip (which was typical of lettuce roots exposed to label PS beads) was usually visible to the naked eye. Confocal images revealed that the PS luminescence signals were mainly located in the vascular system and on the cell walls of the cortex tissue of the roots, indicated that the beads passed through the intercellular space via the apoplastic transport system. Once inside the central cylinder, the 0.2 mum PS beads were transferred from the roots to the stems and leaves via the vascular system following the transpiration stream. We also observed that the PS beads adhered to one another and self-assembled systematically into grape-like and (chain) string-like clusters in the intercellular space of the root and stem vascular tissue of lettuce plant. In contrast to the root and stem, PS beads were dispersed in the leaf tissue. Here, for the first time we provide evidence of the adherence, uptake, accumulation, and translocation of submicrometer MPs within an edible plant. Our findings highlight the previously underappreciated human exposure pathway to MPs through the consumption of contaminated crops and emphasize the need for new management strategies to control the release of MPs waste products into the terrestrial environment. Ultimately, the potential impacts of low range sized MPs on food safety of crop plants and human health need to be urgently considered.

Rapid Micro-Patterning of a Conductive PANI/MWNTs-Polymer Composite Using an Optically-induced Electrokinetics Chip 会议论文 OAI收割
IEEE Nanotechnology Materials and Devices Conference (IEEE NMDC), Honolulu, HI, OCT 16-19, 2012
作者: Liu N(刘娜); Liang WF(梁文峰); Mai, John D.; Dong ZL(董再励); Li WJ(李文荣)

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A flexible, dynamically programmable and low-cost method applicable to micro-patterning of a conductive polymer/carbon nanotube composite solution is significant due to the potential applications in many areas. This paper demonstrates a new micro-patterning method for fabricating electrodes from a conductive polyaniline (PANI)/MWNT composite using an optically-induced electrokinetics (OEK) chip. This method quickly patterns flexible polymeric electrodes with different geometries when a square waveform signal with amplitudes from 16-20 Volts and frequencies from 20-30 kHz are applied. The geometric dimensions of the electrodes can be varied dynamically by controlling the size and exposure time of the light pattern. The surface morphology of electrodes patterned by this method is scanned by an atomic force microscope (AFM) and a scanning electron microscope (SEM) which show that the electrodes are uniform and continuous. Furthermore, the geometric dimensions and resistances of the electrodes are measured and analyzed. Experimental results reveal that the relationship between the resistance and geometries of the electrodes obey Ohm's law and the resistivity of the electrodes is about 0.03 Omega.m.

The approximate calculation of atmospheric path radiance in close range and horizontal direction (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Sensors, Measurement and Intelligent Materials, ICSMIM 2012, December 26, 2012 - December 27, 2012, Guilin, China
作者: Sun Z.; Chen Y.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

Atmospheric path radiance is the key factor in the accuracy of objective radiation measurement. In the traditional radiation character measurements it is compared with the results of MODTRAN and measurement in experiment. It is revealed that the accuracy of software is 7.8% under the help of the atmospheric observation equipment and the formula is 4.9% MODTRAN and other software likewise which could demonstrate the validity of the pproximate calculation formula in close range and horizontal direction. In this article the indeterminacy rate could be around 10~20% in the process of deducing and experiment it is highly restricts the measurement accuracy of objective radiation. For this reason the validity of the approximate calculation formula in close range and horizontal direction is fully proved it is quite significant to develop the study of measure and calculation in path radiance. The approximate calculation formula for path radiance in close range and horizontal direction is expressed in this article which supply a new method in approximate calculation of path radiance for objective radiation measurement. (2013) Trans Tech Publications Switzerland.

A new algorithm for solving the best-fit sphere of optical aspherical surface (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Advances in Materials and Manufacturing, ICAMMP 2011, December 16, 2011 - December 18, 2011, Guilin, China
作者: Lin J.; Lu M.

收藏 | 浏览/下载：40/0 | 提交时间：2013/03/25

To solve the best-fit sphere (BFS) accurately is one of the technological keys for the generating and testing of optical aspherical surfaces. This paper presents a new algorithm for solving the BFS of aspherical surfaces to suppress some deficiencies in the existing BFS algorithms. In the proposed approach it is not only suitable for the conic surface a BFS is constructed but also for higher order aspheres. The obtained asphericity and material removal function is more suitable for the machining and test. (2012) Trans Tech Publications which passes through both sides of endpoints in the section o -?xy of the aspherical surfaces Switzerland. the center of the BFS is shifted along the x-axis and its radius of curvature is automatically computed. The variable step size method is proposed to speed up the convergence of the iteration. Through numerically solving the BFS of conic and cubic surface the advantages of the proposed approach are verified. The results show that the proposed approach is of rapid convergence and high accuracy

A fast target recognition algorithm based on MSA and MSR (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Industrial Control and Electronics Engineering, ICICEE 2012, August 23, 2012 - August 25, 2012, Xi'an, China
作者: Wang Y.; Liu G.; Wang Y.; Wang Y.; Wang Y.

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This paper presents a new fast target recognition algorithm the proposed method is based on Multi-scale Auto convolution(MSA) and Multi-scale Retinex(MSR). As shown by the comparison with original MSA it appears that this new technique solves the problem that MSA algorithm is sensitive to illumination and the computational load is significantly reduced to 1/8th of that of the original MSA algorithm it is also robust to affine transform light projective transform noise thin fog occlusion and illumination change. the performed experiments show that it has fast searching speed and can accurately recognize and locate target in real scenes. 2012 IEEE.

Application of adaptive enhancement means in head and neck CR image (EI CONFERENCE) 会议论文 OAI收割
2012 3rd International Conference on Information Technology for Manufacturing Systems, ITMS 2012, September 8, 2012 - September 9, 2012, Qingdao, China
Zhang M.-H.; Zhang Y.-Y.

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Digital CR of head and neck overcomes the disadvantage of regular X-ray radiography which can not reveal bone and soft tissue position deficiency in one exposing and reduces the Xray radiation dose. Meanwhile various factors cause the decline of image quality and images must be enhanced in order to meet demands of doctor's clinical diagnosis. The general enhancement algorithms don't consider body's structure differences and density characteristics. A new adaptive CR enhancement algorithm was proposed in this article and head and neck CR images were processed with this method and compared with linear unsharp masking method. The experiment proves that the details of CR image enhanced were abundant and enhanced CR image had good visual effect SNR was high as well as detail variance /background variance (DV/BV) indicating that this algorithm is suitable for head and neck CR medical images. (2012) Trans Tech Publications Switzerland.

On hyperspectral remotely sensed image classification based on MNF and AdaBoosting (EI CONFERENCE) 会议论文 OAI收割
2012 3rd IEEE/IET International Conference on Audio, Language and Image Processing, ICALIP 2012, July 16, 2012 - July 18, 2012, Shanghai, China
作者: Yu P.; Yu P.; Gao X.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

As an effective statistical learning tool AdaBoosting has been widely used in the field of pattern recognition. In this paper a new method is proposed to improve the classification performance of hyperspectral images by combining the minimum noise fraction (MNF) and AdaBoosting. Because the hyperspectral imagery has many bands which have strong correlation and high redundancy the hyperspectral data are pre-processed by the minimum noise fraction to reduce the data's dimensionality whilst to remove noise bands simultaneously. Then we use an AdaBoost algorithm to conduct the classification of hyperspectral remotely sensed image. Experimental results show that the classification accuracy is improved and the time of calculation is reduced as well. 2012 IEEE.

An improved hyperspectral classification algorithm based on back-propagation neural networks (EI CONFERENCE) 会议论文 OAI收割
2012 2nd International Conference on Remote Sensing, Environment and Transportation Engineering, RSETE 2012, June 1, 2012 - June 3, 2012, Nanjing, China
作者: Yu P.; Yu P.

收藏 | 浏览/下载：34/0 | 提交时间：2013/03/25

In this paper a new method is proposed to improve the classification performance of hyperspectral images by combining the principal component analysis (PCA) genetic algorithm (GA) and artificial neural networks (ANNs). First some characteristics of the hyperspectral remotely sensed data such as high correlation high redundancy etc. are investigated. Based on the above analysis we propose to use the principal component analysis to capture the main information existing in the hyperspectral images and reduce its dimensionality consequently. Next we use neural networks to classify the reduced hyperspectral data. Since the back-propagation neural network we used is easy to suffer from the local minimum problem we adopt a genetic algorithm to optimize the BP network's weights and the threshold. Experimental results show that the classification accuracy is improved and the time of calculation is reduced as well. 2012 IEEE.

A sub-pixel extraction method for the center of the circular structure from spot array calibration target (EI CONFERENCE) 会议论文 OAI收割
2012 3rd International Conference on Information Technology for Manufacturing Systems, ITMS 2012, September 8, 2012 - September 9, 2012, Qingdao, China
作者: Liu Y.; Zhang T.; Yang H.; Gao X.; Liu Y.

收藏 | 浏览/下载：75/0 | 提交时间：2013/03/25

The imaging measurement system must be calibrated before application. In calibration procedure sub-pixel center extraction is the crucial step for the final accuracy. In this paper a new sub-pixel extraction method is proposed. Edge detection at pixel level is obtained using LOG operator then sub-pixel edge detection is realized using the Facet model. Finally the least squares ellipse fitting is operated on the sub-pixel edge to determine the sub-pixel center. Experiment on a series of simulated images indicates that this algorithm is able to realize the center location accuracy of 0.01-0.02 pixel and meets the requirement of sub-pixel level. (2012) Trans Tech Publications Switzerland.

Improved TOPS about direction of arrival estimation for wideband signals (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Vibration, Structural Engineering and Measurement, ICVSEM2011, October 21, 2011 - October 23, 2011, Shanghai, China
作者: He B.

收藏 | 浏览/下载：17/0 | 提交时间：2013/03/25

The study about the direction-of-arrival (DOA) estimation for wideband signals is a basic topic of Signal Processing. The method called test of orthogonality of projected subspaces (TOPS) does not require initial values to form focusing matrix compared with the coherent signal subspace method (CSSM) but it has poor performance for coherent wideband signals at low signal-to-noise ratio (SNR). Based on the lack of the conventional TOPS this paper reconstructs a set of new matrices with the narrowband correlated matrices coming from the DFT decomposition of the array output and modifies the method frame of the conventional TOPS. So we get a set of reconstructed matrices with full rank corresponding to each frequency bin and which have no array aperture loss. The improved TOPS can estimate the DOA for coherent wideband sources at low SNR and enhances the performance of the conventional TOPS. Simulation results show that the improved TOPS is effective and the total performance of which is similar to the rotational signal-subspace (RSS) method. (2012) Trans Tech Publications.