期刊文献+
共找到6篇文章
< 1 >
每页显示 20 50 100
BFEL束团长度测量系统的离线实验研究
1
作者 朱俊彪 李智慧 +1 位作者 白莎 谢家麟 《高能物理与核物理》 CSCD 北大核心 2006年第z1期78-80,共3页
短和超短束团长度测量技术是发展短波长FEL和高级加速器的关键技术之一.为测试研制的短和超短束团长度测量系统雏形装置,利用黑体辐射仪的连续远红外-毫米波辐射替代BFEL的4ps微束团产生的亚毫米波-毫米波CTR,进行了离线模拟实验,获得... 短和超短束团长度测量技术是发展短波长FEL和高级加速器的关键技术之一.为测试研制的短和超短束团长度测量系统雏形装置,利用黑体辐射仪的连续远红外-毫米波辐射替代BFEL的4ps微束团产生的亚毫米波-毫米波CTR,进行了离线模拟实验,获得良好调制的干涉图.实验表明,该雏形装置软硬件系统的运行满足初期的设计构想;干涉仪经细致的光学调节,可获得较为调制充分的干涉图; LabVIEW编制的测控软件满足控制和采集的基本需要.提出了进一步改善的措施. 展开更多
关键词 束团长度测量装置 黑体辐射 相干渡越辐射 离线实验
原文传递
180 nm CMOS微处理器辐照损伤剂量的实验研究 被引量:1
2
作者 陈法国 郭荣 +3 位作者 李国栋 梁润成 韩毅 杨明明 《核技术》 CAS CSCD 北大核心 2019年第11期57-62,共6页
以180 nm互补金属氧化物半导体(Complementary Metal Oxide Semiconductor, CMOS)工艺制造的STM32微处理器为实验对象,设计了由被测最小系统电路、剂量计、通讯电路和上位机组成的总剂量效应实验条件。利用60Co源分别在63.3 Gy(Si)·... 以180 nm互补金属氧化物半导体(Complementary Metal Oxide Semiconductor, CMOS)工艺制造的STM32微处理器为实验对象,设计了由被测最小系统电路、剂量计、通讯电路和上位机组成的总剂量效应实验条件。利用60Co源分别在63.3 Gy(Si)·h^-1和101.2 Gy(Si)·h^-1剂量率下,对14个实验样品进行了在线辐照,通过数据校验实时判断受照样品的功能运行状态;在227.2~855.0 Gy(Si)累积剂量范围内,对75个实验样品进行了离线辐照,对比样品受照前后的功能运行状态。实验结果表明:片内FLASH存储器是STM32微处理器中最先损伤的硬件单元;受照前后,STM32微处理器各引脚的对地阻抗以及片内模拟数字转换器输出值基本无变化,功耗电流略有增加。63.3 Gy(Si)·h^-1和101.2 Gy(Si)·h^-1在线照射条件下辐照损伤剂量分别为(235.4±16.4)Gy(Si)和(197.4±13.0)Gy(Si);离线照射条件下的辐照损伤剂量介于391.5~497.6 Gy(Si)之间。 展开更多
关键词 总剂量效应 辐照损伤剂量 STM32 微处理器 在线实验 离线实验
下载PDF
一个资讯推荐系统评测方案的设计 被引量:1
3
作者 袁宜霞 《电脑知识与技术》 2023年第9期101-104,共4页
为了提高资讯推荐系统的质量和效果,实现对用户资讯的精准推荐,文章分析资讯推荐系统架构后,制定了一套推荐系统评测方案。该套方案采用众测、用户调研、竞争产品分析对比测试和手工测试等手段对用户画像Profile、UI交互、内容质量、日... 为了提高资讯推荐系统的质量和效果,实现对用户资讯的精准推荐,文章分析资讯推荐系统架构后,制定了一套推荐系统评测方案。该套方案采用众测、用户调研、竞争产品分析对比测试和手工测试等手段对用户画像Profile、UI交互、内容质量、日志统计上报等基础数据进行评测,采用模型离线实验和A/B Test在线实验对推荐系统效果进行评测,在评测过程中通过日志自动化过滤来完善缺陷追查系统,进一步提升推荐系统的研发效率。 展开更多
关键词 推荐系统 模型离线实验 A/B Test在线实验
下载PDF
Equilibrium and kinetics of adsorption of Ca(Ⅱ) ions onto KCTS and HKCTS
4
作者 丁萍 黄可龙 +2 位作者 杨桦 李桂银 刘艳飞 《Journal of Central South University》 SCIE EI CAS 2010年第2期277-284,共8页
The adsorption of Ca( II ) ions from aqueous solution by ehitosan a-ketoglutaric acid (KCTS) and hydroxamated chitosan a-ketoglutaric acid (HKCTS) was studied in a batch adsorption system. The Langmuir and Freun... The adsorption of Ca( II ) ions from aqueous solution by ehitosan a-ketoglutaric acid (KCTS) and hydroxamated chitosan a-ketoglutaric acid (HKCTS) was studied in a batch adsorption system. The Langmuir and Freundlich adsorption models were applied to describing the equilibrium isotherms, and isotherm constants were determined. The kinetics of the adsorption with respect to the initial Ca(II) ions concentration, temperature and pH was investigated. The pseudo-first-order and second-order kinetic models were used to describe the kinetic data and the rate constants were evaluated. The results show that the experimental data fit well to the Langmuir isotherms with a high correlation coefficient (R2). The pseudo-second-order rate expression provides the best fitting kinetic model. The pseudo second-order kinetic model is indicated with the activation energy of 26.22 kJ/mol and 6.16 kJ/mol for KCTS and HKCTS, respectively. It is suggested that the overall rate of adsorption of Ca( II ) ions is likely to be controlled by the chemical process. 展开更多
关键词 chitosan α-ketoglutaric acid hydroxamated chitosan a-ketoglutaric acid Ca(II) ions adsorption kinetics
下载PDF
Experimental study on dispersive soil in western Jilin 被引量:2
5
作者 ZHANG Jing WANG Qing +2 位作者 WANG Wenhua CHEN Hui'e WANG Ying 《Global Geology》 2010年第1期50-55,共6页
In order to research engineering geological properties of the soil in Zhenlai of western Jilin, especially the dispersivity of soil, the authors carried out the basic physicocbemical test and dispersivity identificati... In order to research engineering geological properties of the soil in Zhenlai of western Jilin, especially the dispersivity of soil, the authors carried out the basic physicocbemical test and dispersivity identification test. The results show that the dispersivity of the soil increases with the increase of depth within 0-30 cm (surface soil) ; it decreases as the depth increases within in 30-100 cm. Furthermore, the statistical analysis of the dispersivity indexes and physicochemical propertity indexes show that the DP is positively linear correlated with total soluble salt content, sodium ion content, ESP, pH and organic matter content. Meanwhile, it is negatively linear correlated with clay content, and the linear relationship is better. Through the study of the dispersion mechanism of soil samples, it can be concluded that sodium montmorillonite, higher percentage of exchangeable sodium and high pH are the main reasons for the dispersion of soils in western Jilin. 展开更多
关键词 dispersive soil western Jilin carbonate-saline soil linear relationship
下载PDF
Offline Handwritten Characters Recognition Using Moments Features and Neural Networks
6
作者 Mohamed Abaynarh Lahbib Zenkouar 《Computer Technology and Application》 2015年第1期19-29,共11页
In this paper we revise the moment theory for pattern recognition designed, to extract patterns from the noisy character datas, and develop unconstrained handwritten. Amazigh character recognition method based upon or... In this paper we revise the moment theory for pattern recognition designed, to extract patterns from the noisy character datas, and develop unconstrained handwritten. Amazigh character recognition method based upon orthogonal moments and neural networks classifier. We argue that, given the natural flexibility of neural network models and the extent of parallel processing that they allow, our algorithm is a step forward in character recognition. More importantly, following the approach proposed, we apply our system to two different databases, to examine the ability to recognize patterns under noise. We discover overwhelming support for different style of writing. Moreover, this basic conclusion appears to remain valid across different levels of smoothing and insensitive to the nuances of character patterns. Experiments tested the effect of set size on recognition accuracy which can reach 97.46%. The novelty of the proposed method is independence of size, slant, orientation, and translation. The performance of the proposed method is experimentally evaluated and the promising results and findings are presented. Our method is compared to K-NN (k-nearest neighbors) classifier algorithm; results show performances of our method. 展开更多
关键词 Neural network character recognition orthogonal moments pattern recognition.
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部