期刊文献+
共找到274篇文章
< 1 2 14 >
每页显示 20 50 100
数码相机可量测化的研制 被引量:27
1
作者 杨朝辉 李浩 杨林 《测绘工程》 CSCD 2003年第2期34-37,共4页
普通数码相机在图像获取方面有着很多优势,但它是非量测化相机,不能用普通数字摄影测量方法对其数字图像进行处理。针对这一情况,本文进行了数码相机的可量测化研制,并将其投入实际应用。实际应用的结果证明研制工作是成功的。
关键词 数码相机 图像获取 数字摄影方法 数字图像 量测化
下载PDF
数码相机量测化检校的二维分步检校方法研究
2
作者 苏博 《长江大学学报(自科版)(上旬)》 2014年第8期17-20,共4页
为了提高数码相机量测化检校水平,针对目前数码相机量测化检校方法中存在的对物方控制条件要求高、未知参数间相关性强等缺陷,提出了一种新的数码相机检校方法二维分步检校(MSC)方法,即利用微型平面控制场,避开在一个平差过程中同时解... 为了提高数码相机量测化检校水平,针对目前数码相机量测化检校方法中存在的对物方控制条件要求高、未知参数间相关性强等缺陷,提出了一种新的数码相机检校方法二维分步检校(MSC)方法,即利用微型平面控制场,避开在一个平差过程中同时解算内外方位元素,分步骤独立检校相机的方位元素,避免因同时解算内外方位而产生的未知数之间的相关问题,并减弱像片方位元素对畸变系数解算的影响。实际应用表明,使用该方法能够获得较高的检测精度,因而具有可行性。 展开更多
关键词 数码相机 量测化检校 透视投影变换
下载PDF
基于改进YOLOv8的轻量化小麦病害检测方法 被引量:6
3
作者 马超伟 张浩 +3 位作者 马新明 王键霖 张永爽 张小艾 《农业工程学报》 EI CAS CSCD 北大核心 2024年第5期187-195,共9页
为提高小麦病害检测精度,实现将模型方便快速部署到移动端,该研究提出了一种基于改进YOLOv8的轻量化小麦病害检测方法。首先,使用PP-LCNet模型替换YOLOv8网络结构的骨干网络,并在骨干网络层引入深度可分离卷积(depthwise separable conv... 为提高小麦病害检测精度,实现将模型方便快速部署到移动端,该研究提出了一种基于改进YOLOv8的轻量化小麦病害检测方法。首先,使用PP-LCNet模型替换YOLOv8网络结构的骨干网络,并在骨干网络层引入深度可分离卷积(depthwise separable convolution, DepthSepConv)结构,减少模型参数量,提升模型检测性能;其次,在颈部网络部分添加全局注意力机制(global attention mechanism, GAM)模块,强化特征中语义信息和位置信息,提高模型特征融合能力;然后,引入轻量级通用上采样内容感知重组(content-aware reassembly of features,CARAFE)模块,提高模型对重要特征的提取能力;最后,使用Wise-IoU(weighted interpolation of sequential evidence for intersection over union)边界损失函数代替原损失函数,提升网络边界框回归性能和对小目标病害的检测效果。试验结果表明,对于大田环境下所采集的小麦病害数据集,改进后模型的参数量及模型大小相比原YOLOv8n基线模型分别降低了12.5%和11.3%,同时精确度(precision)及平均精度均值(mean average precision,m AP)相较于原模型分别提高了4.5和1.9个百分点,优于其他对比目标检测算法,可为小麦病害检测无人机等移动端检测装备的部署和应用提供参考。 展开更多
关键词 图像识别 深度学习 目标检 小麦病害 YOLOv8 PP-LCNet
下载PDF
量测化普通数码影像的随点生成核线匹配方法
4
作者 陈新玺 李浩 +1 位作者 顾君晖 杨立君 《测绘科学》 CSCD 北大核心 2011年第3期114-115,138,共3页
基于普通数码影像的近景摄影测量算法成为目前摄影测量研究的热点,本文针对量测化普通数码影像的核线相关匹配特性,提出了一种随点生成核线匹配算法。实验数据表明该算法可在量测化普通数码影像上进行一维匹配,很好地提高了匹配精度和... 基于普通数码影像的近景摄影测量算法成为目前摄影测量研究的热点,本文针对量测化普通数码影像的核线相关匹配特性,提出了一种随点生成核线匹配算法。实验数据表明该算法可在量测化普通数码影像上进行一维匹配,很好地提高了匹配精度和效率。 展开更多
关键词 普通数码影像 量测化 随点生成核线 匹配
原文传递
基于摄影地质编录的数码相机可量测化改造技术
5
作者 刘新中 杨彪 +1 位作者 王永玲 陈新玺 《中南水力发电》 2006年第2期1-5,共5页
一种适用于数码相机可量测化的精密物理检测场及其技术改造方法。在现有技术条件下,数码相机属于非量测相机,其影像不具有量测性。不能直接利用未经技术检测的数码相机采样达到数码摄影地质编录的目的。否则不可能有效地控制影像的几... 一种适用于数码相机可量测化的精密物理检测场及其技术改造方法。在现有技术条件下,数码相机属于非量测相机,其影像不具有量测性。不能直接利用未经技术检测的数码相机采样达到数码摄影地质编录的目的。否则不可能有效地控制影像的几何精度。本文提供一种从精密物理检测场构建入手,实现数码相机可量测化改造的技术解决方案。精密物理检测场由平面网格控制场和三维检测场组成。平面网格控制场是一个高精度的平而标识网格,既可用于数码相机的构像畸变差改正,亦可用于数码摄影地质编录仪及摄影编录经纬仪装置的外方位元素改正。三维检测场则是一个标识三层控制测点的三维合金结构,用于数码相机内方位元素的测定。经龙滩水电站现场摄影地质编录证明:方案设计合理,精度完全满足要求。 展开更多
关键词 数码相机 地质摄影编录 量测化
原文传递
基于全景量测的聚合电网概念、调控方法及其应用 被引量:6
6
作者 郝广涛 韩学山 +3 位作者 林振衡 郭晓君 张友泉 张学清 《电力自动化设备》 EI CSCD 北大核心 2019年第10期187-193,共7页
随着可再生能源发电大规模并入电网发输配用各个部分,为使源网荷在频率限定范围内最大限度地消纳可再生能源有功发电,需对其运行调控实施全局统筹。为此,在电网全景过程化量测条件下给出聚合电网调控方法。提出聚合电网、可观测点、可... 随着可再生能源发电大规模并入电网发输配用各个部分,为使源网荷在频率限定范围内最大限度地消纳可再生能源有功发电,需对其运行调控实施全局统筹。为此,在电网全景过程化量测条件下给出聚合电网调控方法。提出聚合电网、可观测点、可观测点的观测函数和调控函数的概念,在此基础上,给出聚合电网性能指标,提出可观测点、可观测点的观测函数和调控函数之间的互动关系,实现聚合电网渐进调控机制。在线调控算例对所提方法进行了验证。 展开更多
关键词 全景过程 聚合电网 可观 函数 调控函数
下载PDF
微小型粘性泵的内部流场PIV试验研究 被引量:2
7
作者 李金伟 刘树红 +1 位作者 杨帆 吴玉林 《工程热物理学报》 EI CAS CSCD 北大核心 2007年第1期61-63,共3页
根据偏置于两平板间转子两端剪切力小平衡的原理,本文设计加工了偏置式垂直转子微小型粘性泵,并利用PIV技术对其内部的流动进行了可视化量测。通过对试验数据进行进一步的分析,得到了其内部流场的流线分布及相关性能曲线。
关键词 粘性泵 PIV技术 可视 流场
下载PDF
Corrosion behavior of T2 copper in 3.5% sodium chloride solution treated by rotating electromagnetic field 被引量:5
8
作者 张鹏 朱强 +2 位作者 苏倩 郭斌 程树康 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第5期1439-1446,共8页
Copper is susceptible to producing corrosion problems in corrosive environments, which leads to serious safety problems. Thus, investigating the corrosion behavior of copper is of great significance. The effects of ro... Copper is susceptible to producing corrosion problems in corrosive environments, which leads to serious safety problems. Thus, investigating the corrosion behavior of copper is of great significance. The effects of rotating electromagnetic field on corrosion behavior of T2 copper in 3.5% sodium chloride solution with electrochemical measurements were investigated. The results showed that rotating electromagnetic field changed properties of 3.5% sodium chloride solution by increasing the values of temperature and pH and decreasing the values of conductivity and dissolved oxygen. The rotating electromagnetic field improved the corrosion resistance of T2 copper. The corrosion products of T2 copper in treated 3.5% sodium chloride solution were composed of Cu20 and CuCl. The low corrosion rate of T2 copper was resulted from the decrease of dissolved oxygen in 3.5% sodium chloride solution treated by rotating electromagnetic field. 展开更多
关键词 corrosion behavior rotating electromagnetic field electrochemical measurement COPPER
下载PDF
Electrochemical behavior of mesh and plate oxide coated anodes during zinc electrowinning 被引量:2
9
作者 张伟 Michael ROBICHAUD +1 位作者 Edward GHALI Georges HOULACHI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第2期589-598,共10页
The catalytic performance of two oxides coated anodes (OCSs) meshes and one OCA plate was investigated in a zinc electrowinning electrolyte at 38 ℃. Their electrochemical behaviors were compared with that of a conv... The catalytic performance of two oxides coated anodes (OCSs) meshes and one OCA plate was investigated in a zinc electrowinning electrolyte at 38 ℃. Their electrochemical behaviors were compared with that of a conventional Pb-0.7%Ag alloy anode. Electrochemical measurements such as cyclic voltammetric, galvanostatic, potentiodynamic, open-circuit potential (OCP) and in situ electrochemical noise measurements were considered. After 2 h of OCP test, the linear polarization shows that the corrosion current density of the Ti/(IrO2-Ta2O5) mesh electrode is the lowest (3.37μA/cm^2) among the three OCAs and shows excellent performance. Additionally, after 24 h of galvanostatic polarization at 50 mA/cm^2and 38 ℃, the Ti/MnO2mesh anode has the highest potential (1.799 V), followed by the Ti/(IrO2-Ta2O5) plate (1.775 V) and Ti/(IrO2-Ta2O5) mesh (1.705 V) anodes. After 24 h of galvanostatic polarization followed by 16 h of decay, the linear polarization method confirms the sequence obtained after 2 h of OCP test, and the Ti/(IrO2-Ta2O5) mesh attains the lowest corrosion current density. The Ti/(IrO2-Ta2O5) mesh anode also shows better performance after 24 h of galvanostatic polarization with the overpotential lower than that of the conventional Pb-Ag anode by about 245 mV. 展开更多
关键词 oxides coated anode MESH PLATE electrochemical measurement electrochemical behavior
下载PDF
Determination of the Trace Element Contents in Plants Using Atomic Absorption Spectrophotometer 被引量:37
10
作者 高淑云 《Agricultural Science & Technology》 CAS 2008年第2期6-9,共4页
The aim of the study is to investigate the contents of trace element Se, Cd, Pb in three plants including burdock, ginkgol and garlic via graphite furnace atomic absorption and standard addition method. The results sh... The aim of the study is to investigate the contents of trace element Se, Cd, Pb in three plants including burdock, ginkgol and garlic via graphite furnace atomic absorption and standard addition method. The results show that Se in burdock stem, skin and leaf are 32.40, 48.63, 38.10 μg/g, respectively; Cd in burdock stem, skin and leaf are 0. 160 0, 0. 300 0, 0. 140 0 μg/g, respectively; Cd in burdock stem, skin and leaf are 2. 020, 3. 960, 2. 410 μg/g, respectively. In the ginkgo and ginko leaf, Se contents are 17.63 and 16.91 μg/g, respectively ; for Cd are 0. 181 0 and 0.2020μg/g, respectively ; for Pb are 3. 572 and 4. 021 μg/g, respectively. In garlic, Se, Cd and Pb are 73. 900 0, 6. 900 0 and 0. 390 0, respectively. All the standard deviations of measured results are below 2.3%, recovery rate are from 99% to 101%. 展开更多
关键词 Trace elements GFT AAS BURDOCK GINKGO GARLIC
下载PDF
超小型粘性泵内部流场的基础研究
11
作者 李金伟 刘树红 +2 位作者 杨帆 李永 吴玉林 《工程热物理学报》 EI CAS CSCD 北大核心 2005年第4期602-604,共3页
根据偏置于两平板间转子两端剪切力不平衡的原理,本文设计加工了偏置式垂直转子超小型粘性泵,并利用PIV 技术对其内部的流动进行了可视化量测。通过对试验数据进行进一步地分析,得到了其内部流场的流线分布及相关性能曲线。为了更好地... 根据偏置于两平板间转子两端剪切力不平衡的原理,本文设计加工了偏置式垂直转子超小型粘性泵,并利用PIV 技术对其内部的流动进行了可视化量测。通过对试验数据进行进一步地分析,得到了其内部流场的流线分布及相关性能曲线。为了更好地研究其内部流动特性,本文还通过N—S方程对其内部的流动进行了数值模拟计算,并分析比较了计算和试验结果。 展开更多
关键词 粘性泵 可视 流场 性能
下载PDF
Three methods for generating monotonic OWA operator weights with given orness level 被引量:1
12
作者 刘新旺 《Journal of Southeast University(English Edition)》 EI CAS 2004年第3期369-373,共5页
Based on the properties of ordered weighted averaging (OWA) operator and regular increasing monotone (RIM) quantifier, three methods for generating monotonic OWA operator weights are proposed. They are geometric OWA o... Based on the properties of ordered weighted averaging (OWA) operator and regular increasing monotone (RIM) quantifier, three methods for generating monotonic OWA operator weights are proposed. They are geometric OWA operator weights, equidifferent OWA operator weights and the modified RIM quantifier OWA weights. Compared with most of the common OWA methods for generating weights, the methods proposed in this paper are more intuitive and efficient in computation. And as there are more than one solution in most cases, the decision maker can set some initial condition and chooses the appropriate solution in the real decision process, which increases the flexibility of decision making to some extent. All these three OWA methods for generating weights are illustrated by numerical examples. 展开更多
关键词 ordered weighted averaging operator orness measure fuzzy quantifier
下载PDF
STUDY ON OPTIMAL CONTROL OF MUNICIPAL WATER DISTRIBUTION NETWORK 被引量:1
13
作者 张宏伟 杨芳 庄健 《Transactions of Tianjin University》 EI CAS 2001年第3期167-171,共5页
A systematic investigation is made on the problems which are related to the optimal control of the municipal water distribution network.A mathematical model of forecasting the water short term demand is proposed using... A systematic investigation is made on the problems which are related to the optimal control of the municipal water distribution network.A mathematical model of forecasting the water short term demand is proposed using the time series trigonometric function analysis method;the service discharge based macroscopic model of network performance is established using the network structuring method;a relatively satisfactory mathematical model for the optimal control of water distribution network is put forward in view of security and economy,and solved by the constrained mixed discrete variable complex arithmetic.The model is applied in many examples and the results are satisfactory. 展开更多
关键词 water distribution network water demand forecast macroscopic model optimal control
下载PDF
Research into Uncertainty in Measurement of Seawater Chemical Oxygen Demand by Potassium Iodide-Alkaline Potassium Permanganate Determination Method 被引量:1
14
作者 张世强 郭长松 《Marine Science Bulletin》 CAS 2007年第2期18-24,共7页
Using the glucose and L-glutamic-acid to prepare the standard substance according to the ratio of 1:1, and the artificial seawater and the standard substance to prepare a series of standard solutions, the distributio... Using the glucose and L-glutamic-acid to prepare the standard substance according to the ratio of 1:1, and the artificial seawater and the standard substance to prepare a series of standard solutions, the distribution pattern of uncertainty in measurement of seawater COD is obtained based on the measured results of the series of standard solutions by the potassium iodide-alkaline potassium permanganate determination method. The distribution pattern is as follows: Uncertainty in measurement is big and not constant at the high end, but small and constant at the low end. 展开更多
关键词 potassium iodide-alkaline potassium permanganate determination COD uncertainty in measurement
下载PDF
Determination of Ciprofloxacin Lactate by Sodium Tetraphenylboron Method
15
作者 赵彦生 李彦威 +1 位作者 魏文珑 王晋辉 《Journal of Chinese Pharmaceutical Sciences》 CAS 2002年第1期24-27,共4页
This paper describes an effective method for determining ciprofloxacin lactate. An excess of sodium tetraphenylboron was added to precipitate ciprofloxacin lactate in HAc-NaAc buffer solution (pH=4.0). After filtering... This paper describes an effective method for determining ciprofloxacin lactate. An excess of sodium tetraphenylboron was added to precipitate ciprofloxacin lactate in HAc-NaAc buffer solution (pH=4.0). After filtering off the precipitate, the excessive sodium tetraphenylboron in the filtrate was titrated with cetyltrimethylammonium bromide standard solution, with bromophenol blue as indicator. The method is simple and rapid, it has been applied to the determination of ciprofloxacin lactate raw material with satisfactory results. The recovery was between 99.66% and 100.2%, the relative error was less than ±0.40%. Experiments showed that the method gave the same results as the approach using nonaqueous titration (ChP). 展开更多
关键词 Ciprofloxacin lactate Sodium tetraphenylboron Bromophenol blue Cetyltrimethylammonium bromide
下载PDF
Impacts of Agricultural Non-point Pollution on Water-source Area in Songhua Dam 被引量:2
16
作者 钟萍 段宗亮 《Agricultural Science & Technology》 CAS 2012年第11期2375-2378,共4页
[Objective] The aim was to research impacts of agricultural non-point pol- lution on water-source region in Songhua Dam, laying foundation for control of water pollution and scientific protection of water-source regio... [Objective] The aim was to research impacts of agricultural non-point pol- lution on water-source region in Songhua Dam, laying foundation for control of water pollution and scientific protection of water-source region. [Method] Water in Muyang River, lengshui River and Zizania aquatica region were sampled to measure content of pollutants in water and conclude relation between water contamination and agri- cultural non-point pollution to find the major cause of pollution. [Result] Organic pollu- tant in Muyang River was higher; N and P contents in Lengshui River were higher; the measured indices in Zizania aquatica region excessively exceeded related stan- dard. [Conclusion] The chemical fertilizers and pesticides are the toxic materials lead- ing to water contamination and constitute a major cause of pollution in Songhua Dam water-source region. Agricultural non-point pollution should be controlled in a scientific way. 展开更多
关键词 Songhua Dam Reservoir Water-source region Agricultural non-pointpollution
下载PDF
Morphometrics analysis on the hind wing of Tetrigides(Orthoptera) and its application in taxonomy 被引量:1
17
作者 张荣娇 周善义 邓维安 《Entomotaxonomia》 CSCD 2016年第3期175-183,共9页
The morphological characteristics of the hind wing venation of tetrigids were analyzed on the basis of morphometric measurement, with 20 species and 18 different variables selected for this study. Results show that th... The morphological characteristics of the hind wing venation of tetrigids were analyzed on the basis of morphometric measurement, with 20 species and 18 different variables selected for this study. Results show that three principal components have a higher load at the length between the starting point of the costal vein and the tip of the fourth anal vein, between the tip of the costal vein and the tip of the third anal vein, and between the tip of the costal vein and the tip of the eleventh anal vein. There exists a contrast between wing length and width. 展开更多
关键词 morphometric measurement insect morphology evolutionary development
下载PDF
Measurement of Concentration of Sorbent Particles and Water Droplets in Hydration Desulfurization Reactor with PIV
18
作者 赵长遂 吴树志 +3 位作者 刘现卓 肖军 陆勇 王式民 《Journal of Southeast University(English Edition)》 EI CAS 2002年第1期88-91,共4页
Vortexing limestone injection into furnace combined with calcium lime hydration in the downstream is the most promising technology for controlling SO 2 emission. Particle imaging velocimetry (PIV) is used to measure ... Vortexing limestone injection into furnace combined with calcium lime hydration in the downstream is the most promising technology for controlling SO 2 emission. Particle imaging velocimetry (PIV) is used to measure the gas liquid solid three phase flow field in a reactor. By image processing based on newly developed software, the number concentrations of sorbent particles and water droplets are presented. The measuring results are very helpful for better understanding the desulfurization mechanism and optimizing configurational and operational parameters in the hydration reactor. 展开更多
关键词 particle image velocimetry DESULFURIZATION particle water droplet CONCENTRATION
下载PDF
Effects of trace element and purification on properties of AZ80 magnesium allo 被引量:2
19
作者 李应举 罗天骄 杨院生 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第B07期407-410,共4页
The effects of trace element Fe on the corrosion behavior of AZ80 magnesium alloy were investigated by salt spray test and electrochemical measurements.The results show that the corrosion rate decreases with decreasin... The effects of trace element Fe on the corrosion behavior of AZ80 magnesium alloy were investigated by salt spray test and electrochemical measurements.The results show that the corrosion rate decreases with decreasing the trace element Fe content in an approximately linear relation even though the amount of trace element Fe reduces to 0.000 2%(mass fraction).The electrochemical measurements show that the corrosion potential(φcorr)of the alloy with lower trace element Fe content shifts to less negative value.It is suggested that the control trace element by purification is an effective way to enhance the corrosion resistance of AZ80 magnesium alloy. 展开更多
关键词 magnesium alloy PURIFICATION corrosion rate trace element
下载PDF
Digital characterization and mathematic model of sodium penetration into cathode material for aluminum electrolysis 被引量:5
20
作者 吕晓军 李庆余 +1 位作者 赖延清 李劼 《Journal of Central South University》 SCIE EI CAS 2009年第1期96-100,共5页
The sodium expansion curves of semi-graphitic cathode measured with the improved Rapoport-Samoilenko apparatus. The and TiB2/C composite cathode with different TiB2 contents were mathematic model of the sodium expansi... The sodium expansion curves of semi-graphitic cathode measured with the improved Rapoport-Samoilenko apparatus. The and TiB2/C composite cathode with different TiB2 contents were mathematic model of the sodium expansion was deduced on the basis of the experimental results. The sodium expansion parameter (a) and penetration rate factor (Q), were introduced into the model The model was validated with the experimental sodium expansion curves self-measured and reported. The results show that the variation tendency of the sodium expansion parameter (a) and penetration rate factor (Q) is consistent with that of the experimental curves. The model is capable of not only conveniently judging the cathode quality, but also favorably establishing a unified standard of the resistance to sodium penetration of cathode. 展开更多
关键词 aluminum electrolysis CATHODE sodium expansion modeling CHARACTERIZATION
下载PDF
上一页 1 2 14 下一页 到第
使用帮助 返回顶部