13 research outputs found
Landmark Images Collecting and Labeling Based on Web Implicit Supervision
网络的发展为我们带来了丰富的视觉信息,利用图像搜索引擎可以搜集到成千上万的图像,这其中包含有大量的各地风景名胜图像,它们从各种视角、各种季节、各种时段展现着旅游名胜的美。如何对这些风景图像进行结构化组织是网络视觉研究的一个热点问题。本文针对地标风景图像进行了深入的研究,按视觉一致性对地标图像进行聚类,进行地标图像的摘要,并对地标进行定位。该研究对地标的三维重建、地标图像的浏览具有重要的作用。本文的研究工作和学术贡献如下: 1. 提出一种按空间分布结合语义的地标图像组织和过滤方法。针对网络引擎搜集的噪声图像集,利用GIST描述子对图像进行全局特征描述,然后设计分层聚类方法对图像进行聚类。对得到...Network development has brought us a wealth of visual information. We can get thousands of landmark images, through the network image search engines. These images embody the beauty of tourist attractions by different perspectives, different seasons, different weather, and different times. How to structure and organize these images is a hot issue in network vision research. In this paper, we study ...学位:工学硕士院系专业:信息科学与技术学院计算机科学系_计算机应用技术学号:2302008115323
Liquid and solids charging : charge excess and surface properties effect
Orientador: Fernando GalembeckTese (doutorado) - Universidade Estadual de Campinas, Instituto de QuímicaResumo: Nesta tese, investigou-se a eletrização e os mecanismos de acúmulo de carga em gotas de água e filmes de polietileno, bem como, avaliou-se o efeito das cargas elétricas em algumas propriedades desses materiais. A eletrização de água foi realizada de duas formas: pelo contato com uma superfície metálica polarizada ou expondo as gotas de água a um potencial eletrostático criado através do ar por um eletrodo sem contato. Em ambos os casos, observou-se que a água adquire excesso de cargas e que o valor detectado excede o limite de Rayleigh em algumas dezenas. Verificou-se que a presença de cargas em gotas de água leva à diminuição de sua tensão superficial e ao aumento espontâneo de sua área, por outro lado, não foi observada mudança na sua densidade. O reconhecimento desses fatos deve contribuir para uma maior compreensão de vários fenômenos eletrostáticos que ocorrem na presença de água em estado líquido ou adsorvida. A superfície superior e inferior de filmes de polietileno expostos à descarga corona adquire potencias elevados e opostos formando um filme dipolar. No entanto, a molhabilidade, a composição química e a rugosidade das duas superfícies são bastante diferentes. Enquanto a superfície superior é modificada pelo tratamento corona, a superfície inferior, apesar de se tornar eletrizada, permanece inalterada após o tratamento. Estes resultados mostram que a eletrização da superfície voltada para o eletrodo corona ocorre por um processo diferente da superfície oposta. A eletrização da superfície inferior durante o processo corona abre possibilidades para aplicações onde seja desejável ter um filme eletrizado, porém sem modificar as características originais da superfícieAbstract: In this thesis, we investigated charging process and the mechanism of charge build-up in water droplets and polyethylene films as well. We evaluated the effect of electrical charges on some properties of these materials. Charging of water drops was done using two different methods by: contacting an electrified metal or exposing water to the electrostatic potential created through air by a noncontacting biased electrode. In both cases, water drops acquire net electric charge and its value exceeds the Rayleigh limit in a few tens. It was verified that the presence of charges in water droplets leads to reduced surface tension and increased spontaneous its area, but there was no change in density. Recognition of these facts should contribute to further understanding of various electrostatic phenomena taking place in the presence of liquid or adsorbed water. Top and bottom surfaces of polyethylene (PE) films exposed to corona discharge display large and opposite electrostatic potentials, forming an electric bilayer. However, water wetting, chemical composition and roughness of the two surfaces are quite different. While the top surface is modified by corona treatment, the bottom surface is charged but remains unchanged after treatment. These results show that poling the surface closer to the corona electrode triggers another but different charge build-up process at the opposite surface. Charging of the bottom surface during corona opens possibilities for applications where it is desirable to have a polymer film charged, but without modifying the original characteristics of the surfaceDoutoradoFísico-QuímicaDoutora em Ciência
浮游植物中一氧化氮的生理作用研究进展
一氧化氮(NO)作为一种具有生物活性的气体自由基分子,它的功能代表了生物学系统中信号传递的新途径。大量证据表明, NO在浮游植物细胞中的功能和在高等动植物中类似,具有调节生长和参与抗逆性的作用, NO和ROS可能作为信号分子参与介导浮游植物程序性死亡(PCD)过程。文章较全面地介绍了NO在浮游植物中的产生途径、测定方法、生理功能和PCD的关系及作为信号分子的作用,并对该领域今后的研究进行了展望
半导体激光器在氧气探测中的应用及关键技术
氧气探测在工业、医疗等诸行业都有重要意义。本文简述了近几年发展起来的TD-LAS技术之特点及优势,评述了各种半导体激光器作为激发光源用于TDLAS技术进行氧气探测的性能,着重讨论了在氧气探测方面具有发展前景和竞争优势的DFB和VCSEL结构激光器光源的应用和进展
高效液相色谱法定量测定美氟尼酮(吡非尼酮的新衍生物)的浓度及其在肝微粒体中的初始药代动力学研究(英文)
本研究开发了一种简单可靠的HPLC-UV方法用于美氟尼酮的测定。生物分析步骤包括从500μL肝微粒体系统中通过甲醇沉淀蛋白质提取美氟尼酮。色谱条件:色谱柱为Agilent TC-C18柱(4.6 mm×250 mm,5μm),流动相为10 mM甲酸铵(用10%的甲酸调PH至2.9)–乙腈(70:30,v/v),流速为1.0 mL/min,UV检测波长设定在245 nm。美氟尼酮和吡非尼酮(内标物)分别在6.0和9.7分钟洗脱,总运行时间为12分钟。根据美国食品和药物管理局生物分析指南,进行了方法验证,结果符合验收标准。美氟尼酮在肝微粒体中的标准曲线在0.5–16μg/mL范围内呈线性关系。美氟尼酮内和外间精确度低于9.0%,偏差在±10.0%以内。美氟尼酮在肝微粒体中孵育后,该方法成功应用于药代动力学研究。The National Natural Science Foundation of China(Grant No.81302819),the National Natural Science Foundation of China(Grant No.C0709-31201056);;the Fundamental Research Funds for the Central Universities of China(Grant No.7601110179);;the Fundamental Research Funds for the Central south Universit..
A metal-semiconductor-metal detector based on ZnO nanowires grown on a graphene layer
National Natural Science Foundation of China [61176049, 61307047]; Program for New Century Excellent Talents in Fujian Province University (NCETFJ); China Scholarship Council (CSC)High quality ZnO nanowires (NWs) were grown on a graphene layer by a hydrothermal method. The ZnO NWs revealed higher uniform surface morphology and better structural properties than ZnO NWs grown on SiO2/Si substrate. A low dark current metal-semiconductor-metal photodetector based on ZnO NWs with Au Schottky contact has also been fabricated. The photodetector displays a low dark current of 1.53 nA at 1 V bias and a large UV-to-visible rejection ratio (up to four orders), which are significantly improved compared to conventional ZnO NW photodetectors. The improvement in UV detection performance is attributed to the existence of a surface plasmon at the interface of the ZnO and the graphene
GaN light-emitting diodes with an Al-coated graphene layer as a transparent electrode
We fabricated GaN light-emitting diodes with a layer of graphene as a transparent electrode. A 3-nm-thick Al layer was deposited on the graphene layer by electron-beam evaporation. This Al layer plays an important role in protecting the graphene layer during the device fabrication process. Moreover, this Al layer can also enhance the light emission of GaN light-emitting diodes through the investigation of electroluminescence spectra. The significantly improved light emission is attributed to the current expansion, the enhanced plasmonic density of states, and the decreased nonradiative recombination rate. ? 2014 The Japan Society of Applied Physics
Synthesis of ZnO nanostructures by spontaneous oxidation of Zn films on p-type silicon substrates
ZnO nanostructures have been synthesized on p-type silicon substrates using a two-step, spontaneous oxidation of Zn films method at room temperature. The samples both with and without a thin layer of gold in different positions have been spontaneously oxidized in a humid atmosphere for seven days to form nanosheets and ball-cactus like nanostructures. Diverse morphologies of hierarchical ZnO nanostructures have been obtained by annealing the samples at 700 C in a nitrogen atmosphere for 1 h. A growth mechanism has been proposed for the formation of different ZnO nanostructures. It was found that the band-gap emission can be greatly improved and that the defect emission is suppressed to a noise level when a thin layer of Au was deposited between the Zn and the Si substrate. Moreover, our results show that the ZnO/p-Si heterojunction exhibits good performance for visible spectrum detection
绿色农业新技术集成研究与示范
一、该项目针对农业生产中食品安全和环境污染问题,开展了S-诱抗素、新奥霉素、壳寡糖、棉铃虫病毒杀虫剂与昆虫病原线虫生物制剂、功能性堆肥及其浸提液工业化生产等的试验和示范,立项准确,针对性强,意义重大。 二、项目研究出S-诱抗素等生物制剂及其生产工艺、工厂化技术;研究开发出昆虫病原线虫活体繁殖技术,实现了工厂化生产;研究开发了两种功能性堆肥及浸提液,提出了“功能性堆肥+秸秆生物反应堆+堆肥浸提液+S-诱抗素等生物制剂”健康、安全设施蔬菜生产模式;在宁夏实现了地上、地下,土壤、作物生物制剂联防技术体系,为低耗、高效、安全、健康农产品生产开辟了新途径。 三、在S-诱抗素、新奥霉素高产菌株的生产工艺,昆虫病原线虫活体繁殖工厂化生产方面取得了新突破;在S-诱抗素、新奥霉素、壳寡糖、棉铃虫病毒杀虫剂、功能性堆肥及其浸提液集成应用控制作物病虫害等方面有创新。研究成果达到了国内先进水平,S-诱抗素、新奥霉素高产菌株的生产工艺研究达到国际领先。 四、项目执行期间,在宁夏15个市县建立核心试验基地14个,示范推广点40个,累计推广面积17万亩,新增效益9600万元。获得发明专利4项,实用新型专利1项,制定地方标准5项,专著1部,发表论文19篇(其中SCI收录6篇)。培训农技人员300人次,农民4700多人次