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食用蔬菜能吸收和积累微塑料 期刊论文
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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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.

An analysis of first-time and repeat visitors to Korean national parks from 2007 and 2013 期刊论文
Journal of Mountain Science, 2017, 卷号: 14, 期号: 12, 页码: 2527-2539
作者: Yunseon CHOE; Michael A. SCHUETT; Kyu-Won SIM

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ThIs Paper ExamIned VIsiTors To Bukhansan NatiOnal Park In Korea Based On First-time And Repeat vIsitatiOn. Bukhansan NatiOnal Park Is Korea's Most Heavily vIsited NatiOnal Park With Annual vIsitatiOn Of Six milliOn VIsiTors In 2015. Data Used In ThIs Article Were Collected On-site In The Park In 2007 And 2013 By The Korea NatiOnal Park Service (Knps). The Study Variables Included Socio-demographics Travel Behavior Motivation And Satisfaction With Park Attributes Services And Facilities. Data Were Analyzed By Each Study Year For First-time And Repeat Visitors. Results Showed Significant Differences For Both First-time And Repeat Visitors.On Several Socio-demographic Travel Behavior And Motivation Variables Within Each Study Year. For Satisfaction With Park Attributes Facilities And Services First-time VisiTors Were Significantly Different From Repeat VisiTors On Seven Variables For Both Years. implicatiOns Are Given Regarding Programs And Services To Improve visiTor satisfactiOn And Sustain The Natural Cultural And HisTorical Resources At Bukhansan nAtional Park And Other nAtional Parks In Korea. Future Research Suggestions Are Provided To Learn More About visiTor Characteristics StAndards Of Quality And Preferences In The National Parks.

Quantitative analysis of COLREG rules and seamanship for autonomous collision avoidance at open sea 期刊论文
Ocean Engineering, 2017, 卷号: 140, 页码: 281-291
作者: He, Yixiong; Jin, Yi; Huang, Liwen; Xiong, Yong; Chen, Pengfei

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ACA automatic collision avoidance CA collision avoidance COLREG International Regulations for Preventing Collisions at Sea 1972 CPA closest point of approach CR risk of collision CS close-quarters situation DCPA distance to the closest point of approach FTCS first time-in-point of close-quarters situation FTID first time-in-point of immediate danger ID immediate danger MMG mathematical modeling group OS own ship PCR potential risk of collision RPM Revolutions Per Minute SD ship domain TCPA time to the closest point of approach TCS time to close-quarters situation TID time to immediate danger TS target ship Quantitative analysis COLREG rules and Seamanship Modeling Navigation Autonomous collision avoidance

Structural time-dependent reliability assessment of the vibration active control system with unknown-but-bounded uncertainties 期刊论文
STRUCTURAL CONTROL & HEALTH MONITORING, 2017, 卷号: 24
作者: Wang, Lei; Wang, Xiaojun; Li, Yunlong; Lin, Guiping; Qiu, Zhiping

收藏 | 浏览/下载：4/0 | 提交时间：2019/12/30

active control system for structural vibration interval process model the first-passage theory time-dependent reliability unknown-but-bounded uncertainties

Image mosaic technique based on the information of edge (EI CONFERENCE) 会议论文
2012 3rd International Conference on Digital Manufacturing and Automation, ICDMA 2012, July 31, 2012 - August 2, 2012, Guilin, Guangxi, China
Wu Z.-G.; Wang M.-J.; Wang Y.-Q.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

Image mosaic is an important branch in the field of image processing. This paper designs and realizes an image mosaic technique based on the information of edge. The technology is suitable for engineering application. First of all two images of the adjoining frames are processed by convolution operation get the edge images. And then we cut edge image into pieces and compute their spatial frequency. According to the value of the spatial frequency select reasonable registration model group. We compute correlation strength and the value of movement offset which are the model group and the current frame edge image. We can complete image mosaic by them. We use video sequence which of the resolution is 1024 * 768 do the experiment. The results show that the method has good effect and strong adaptability. Algorithm is high efficiency which running time is 24 ms. It is suitable for real-time processing requirements of the application. This method is an effective mosaic technique which is suitable for engineering application. 2012 IEEE.

早产儿视网膜病变的筛查策略探讨 期刊论文
2012
熊永强; 刘生荣; 陈立宇; 廖宝兰; 吕月娥; 陈美玲; 林新祝

收藏 | 浏览/下载：5/0 | 提交时间：2016/05/17

早产儿视网膜病变筛查标准初次筛查时间 Retinopathy of prematurity Screening criterion Screening time for the first time

Performance test of steel tube enclosed thermistors in air temperature measurements (EI CONFERENCE) 会议论文
3rd International Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2011, January 6, 2011 - January 7, 2011, Shanghai, China
Chen H.; Peng J.; Yan F.; Sui Y.; Yang H.

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The performances of two steel tube enclosed precision thermistors are tested in a well controlled air environment to determine if the thermistors have enough accuracy for 0.01C levels of air temperature gradient measurement. Three Fluke's 5641 and three 5610 thermistors were tested for 24 hours in Fluke's 7008 calibration bath in the first step. In the second step the performances of these two thermistors in steady state and transient state air temperature environments were tested for 8 hours separately. The results illustrate that two of the 5641s were airproofed in a temperature well controlled tube when steel tube enclosed precision thermistors are used in air temperature measurement there are unstable departures from each other with a maximum 8.8 mC in constant air medium and 27 mC in temperature changing air medium. The transient-time errors are too large to show the true amounts of temperature changes for air temperature measurement. 2011 IEEE.

SGCMG design and time accumulation error analysis (EI CONFERENCE) 会议论文
2011 International Conference on Mechatronic Science, Electric Engineering and Computer, MEC 2011, August 19, 2011 - August 22, 2011, Jilin, China
Xu W.

收藏 | 浏览/下载：15/0 | 提交时间：2013/03/25

SGCMG receives much concern due to the performance of its excellent torque output on spacecraft control it has been applied to large foreign spacecraft already but late start and only limited to configurations and steering law study in China. Based on the needs of agility small satellites this article explained the method of SGCMG principle prototype design and proposed the influence on SGCMG output torque precision generated by time accumulation error first time. This article provided a new idea for future SGCMG project development and had good reference value for SGCMG research. 2011 IEEE.

Design of motion compensation mechanism of satellite remote sensing camera (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Space Exploration Technologies and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Gu S.; Yan Y.; Xu K.; Jin G.

收藏 | 浏览/下载：37/0 | 提交时间：2013/03/25

Multi-focus image fusion algorithm based on adaptive PCNN and wavelet transform (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Imaging Detectors and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Wu Z.-G.; Wang M.-J.; Han G.-L.

收藏 | 浏览/下载：34/0 | 提交时间：2013/03/25

Being an efficient method of information fusion image fusion has been used in many fields such as machine vision medical diagnosis military applications and remote sensing.In this paper Pulse Coupled Neural Network (PCNN) is introduced in this research field for its interesting properties in image processing including segmentation target recognition et al. and a novel algorithm based on PCNN and Wavelet Transform for Multi-focus image fusion is proposed. First the two original images are decomposed by wavelet transform. Then based on the PCNN a fusion rule in the Wavelet domain is given. This algorithm uses the wavelet coefficient in each frequency domain as the linking strength so that its value can be chosen adaptively. Wavelet coefficients map to the range of image gray-scale. The output threshold function attenuates to minimum gray over time. Then all pixels of image get the ignition. So the output of PCNN in each iteration time is ignition wavelet coefficients of threshold strength in different time. At this moment the sequences of ignition of wavelet coefficients represent ignition timing of each neuron. The ignition timing of PCNN in each neuron is mapped to corresponding image gray-scale range which is a picture of ignition timing mapping. Then it can judge the targets in the neuron are obvious features or not obvious. The fusion coefficients are decided by the compare-selection operator with the firing time gradient maps and the fusion image is reconstructed by wavelet inverse transform. Furthermore by this algorithm the threshold adjusting constant is estimated by appointed iteration number. Furthermore In order to sufficient reflect order of the firing time the threshold adjusting constant is estimated by appointed iteration number. So after the iteration achieved each of the wavelet coefficient is activated. In order to verify the effectiveness of proposed rules the experiments upon Multi-focus image are done. Moreover comparative results of evaluating fusion quality are listed. The experimental results show that the method can effectively enhance the edge details and improve the spatial resolution of the image. 2011 SPIE.

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