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基于W2ID准则的RichModel隐写检测特征选取方法 被引量:3
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作者 马媛媛 徐久成 +2 位作者 张祎 杨春芳 罗向阳 《计算机学报》 EI CAS CSCD 北大核心 2021年第4期724-740,共17页
数字隐写是信息安全领域一个重要分支,其通过将秘密信息嵌入到数字图像、声音、视频等文件中并通过公开信道(如:Email邮箱、微博推文和即时通信等)进行传递,从而实现信息的隐蔽通信.图像自适应隐写是近年来数字隐写技术的研究热点,而Ric... 数字隐写是信息安全领域一个重要分支,其通过将秘密信息嵌入到数字图像、声音、视频等文件中并通过公开信道(如:Email邮箱、微博推文和即时通信等)进行传递,从而实现信息的隐蔽通信.图像自适应隐写是近年来数字隐写技术的研究热点,而Rich Model特征是检测图像自适应隐写的一大类主流高维特征,这类高维特征在实现对图像自适应隐写较高检测正确率的同时,带来了高额的计算开销和和存储开销,并使得隐写检测中的分类器训练变得极为困难.为此,本文提出了一种基于加权类间距离和类内距离差异准则(W2ID准则)的图像Rich Model隐写检测特征选取方法(记为W2ID-α方法).首先,在对Fisher-based方法这一隐写检测特征经典选取方法进行原理分析的基础上,指出该方法可能存在误删有用特征分量、保留冗余和冲突特征分量的不足;然后,通过将"类内距离差异"原则引入到隐写检测特征分量的可分性度量,提出了基于类间距离和类内距离差异的特征可分性度量准则(简记为2ID准则),给出了类内距离差异的一个相关性质;同时,为了合理体现"类间距离"的重要性,本文提出了基于频数统计加权法的权重分配算法,为该准则分配合理权重,使得对特征分量可分性的度量结果相比传统的Fisher准则更为准确;最后,依据W2ID准则的度量结果,基于决策粗糙集α-正域约简方法约简隐写检测特征分量,并在约简特征分量过程中,将每次处理一个特征分量改进为每次处理一组特征分量,以提升决策粗糙集α-正域约简的效率.提出的W2ID-α方法因无需设置可分性下限,避免了阈值设置不准确可能造成去除有用特征分量的问题,从而消除了现有Steganalysis-α隐写检测特征选取方法依赖经验参数的问题.基于数字隐写领域通用的BOSSbase-1.01图像库10 000幅原始图像和基于经典SI-UNIWARD隐写方法生成的多组隐写图像,针对从这些图像组每幅图像中提取的35263维J+SRM特征和17000维GFR特征(两类典型的图像Rich Model隐写检测特征),进行了一系列特征选取实验,结果表明:本文提出的W2ID-α方法能够在大幅降低Rich Model隐写检测特征维数的同时,基于选取后特征的隐写检测提高了对隐写图像的检测正确率,与Fisher-based、Steganalysis-α和PCA-based等现有典型特征选取方法相比具有显著优势,如对嵌入率=0.1的SI-UNIWARD隐写图像,基于提出的W2ID-α方法将J+SRM特征从35 263维降到2723维的同时,还提高了 3.63%的检测正确率. 展开更多
关键词 隐写检测 richmodel 特征选取 W2ID准则 α-正域约简 Fisher-based方法
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An Isotopic(Sr,Nd and Pb) Tracer Study on the Xiaoxinancha Gold-rich Copper Deposit in Yanbian,China:Implication for the Geodynamic Model of Diagenesis and Metallogenesis 被引量:7
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作者 MEN Lanjing SUN Jinggui +3 位作者 ZHANG Zengjie LI Yixin XING Shuwen CUI Peilong 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2011年第1期175-188,共14页
An isotopic study was systemically carried out on the granitic complex,diorite-porphyrite, ores and ore minerals of the 103 Ma Xiaoxinancha gold-rich copper deposit in Jilin province to determine the geodynamic model ... An isotopic study was systemically carried out on the granitic complex,diorite-porphyrite, ores and ore minerals of the 103 Ma Xiaoxinancha gold-rich copper deposit in Jilin province to determine the geodynamic model of diagenesis and metallogenesis.Results show that the initial Nd and Sr isotopic compositions of the granitic complex are in the range of 0.70425-0.70505 for(87Sr/86Sr)i, 0.51243-0.51264 for INd,and -1.31 to +2.64 forεNd(t);those of the diorite-porphyrite are in the range from 0.70438-0.70448 for(87Sr/86Sr),,0.51259-0.51261 for INd,and +1.56 to +2.09 forεNd(t).For ores and sulfides,the(87Sr/86Sr)i,7Nd,andεNd(t) values are in the range from 0.70440-0.70805,0.51259- 0.51279 and +1.72 to +5.56,respectively.The Pb isotopic ratios of the granitic complex range from 18.2992-18.6636 for 206Pb/204Pb,from 15.5343-15.5660 for 207Pb/204Pb,and from 38.1640-38.5657 for 208Pb/204Pb For diorite-porphyrite,the isotopic ratios of 206Pb/204Pb,207Pb/204Pb and 208Pb/204Pb are 18.3919,15.5794 and 38.3566,respectively,whereas those of the ores and ore sulfides vary from 18.2275-18.3770 for 206Pb/204Pb,from 15.5555-15.5934 for 207Pb/204Pb and from 38.1318-38.3131 for 208Pb/204Pb.The results indicate that the mineralization was correlated to the formation and evolution of the granitic complex and the diorite-porphyrite.Combining with the reported data in petrologic characteristics,elemental geochemistry and chronology,conclusions can be drawn that the geodynamic settings of diagenesis and metallogenesis of this deposit were consistent with the subduction of the Izanagi oceanic plate during the Early Cretaceous.The diorite-porphyrite was formed by the emplacement of the adakitic magma triggered by partial melting of the enriched mantle,which originated from the derivative continental lithospheric mantle metasomatized by dehydration fluids from the subducting oceanic crust.The granitic complex was produced by fractional crystallization of the mixture between the adakitic magma and the high-K calc-alkaline acidic magma,which were generated by the remelting of the lower crust in the course of intraplate upwelling of the adakitic magma.The ore-bearing fluid reservoir convened in a late stage of the evolution of the mixed magma chamber. 展开更多
关键词 Sr-Nd-Pb isotope endogenic mineralization theory geodynamic model gold-rich copperdeposit Xiaoxinancha
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Modeling Bat Species Richness and Spatial Distribution in Burkina Faso
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作者 Napoko Malika Kangoyé Adama Oueda +3 位作者 Rimwaodo Pierre Silga Idrissa Ouedraogo Wendengoudi Guenda Boureima Gustave Kabre 《Open Journal of Ecology》 2021年第11期790-806,共17页
The spatial distribution of bats in Burkina Faso is little-known. Previous studies have only described the bat species’ richness in Burkina Faso. This study was conducted to highlight bat species’ richness distribut... The spatial distribution of bats in Burkina Faso is little-known. Previous studies have only described the bat species’ richness in Burkina Faso. This study was conducted to highlight bat species’ richness distribution within Burkina Faso and environmental variables that influence this distribution with the aim to give support for protection and further sampling for biodiversity. The Species Distribution Models (SDMs) were used to perform this study. To do that, species occurrences were collected throughout literature and field sampling and correlated to environmental variables through the Maxent software (Maximum Entropy). Our modeling variables included climate, vegetation cover, topography and hydrography data. The Jackknife test was performed to determine the importance of environmental variables that influence the species distribution model. The results showed that bats are present in all areas of vegetation in Burkina Faso. Species richness varies across the country. The species richness for major families increases from North to South. The total annual precipitation and topography are the main variables that positively influence bats distribution in Burkina Faso but the bare ground cover and standard deviation of the maximum temperature negatively influence this distribution. This modeling approach of bat species richness is important for policies makers and represents an invaluable tool in ecological management, particularly in the current context of climate change. 展开更多
关键词 Bats Distribution Species model richness MAXENT Burkina Faso
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Crystal Structure Evolution of the Cu-rich Nano Precipitates from bcc to 9R in Reactor Pressure Vessel Model Steel 被引量:7
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作者 Liu FENG Bangxin ZHOU +1 位作者 Jianchao PENG Junan WANG 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2013年第6期707-712,共6页
The crystal structure evolution of the Cu-rich nano precipitates from bcc to 9R during thermal aging was studied in nuclear reactor pressure vessel (RPV) model steels. The specimens, contained higher copper and nick... The crystal structure evolution of the Cu-rich nano precipitates from bcc to 9R during thermal aging was studied in nuclear reactor pressure vessel (RPV) model steels. The specimens, contained higher copper and nickel contents than commercially available one, were heated at 890 ~C for 0.5 h and then water quenched followed by tempering at 0(50 ~C for I0 h and aging at 400 ~C for 1000 h. It was observed that bcc and 9R orthogonal structure, as well as 9R orthogonal and 9R monoclinic structure, coexist in a single Cu-rich nano precipitate. Further analyses pointed out that Cu-rich nano precipitates of bcc structure were not stable, it may preferentially transform to 9R orthogonal structure and then to 9R monoclinic structure. This results showed that the crystal structure evolution of the Cu-rich nano precipitates was complex. 展开更多
关键词 Reactor pressure vessel model steel Thermal aging Cu-rich nano precip-itates Structure evolution HRTEM
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Response Surface Modeling of Fuel Rich and Fuel Lean Catalytic Combustion of the Stabilized Confined Turbulent Gaseous Diffusion Flames 被引量:2
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作者 Tahani S. Gendy Salwa A. Ghoneim Amal S. Zakhary 《World Journal of Engineering and Technology》 2019年第1期1-17,共17页
The Response Surface Methodology (RSM) has been applied to explore the thermal structure of the experimentally studied catalytic combustion of stabilized confined turbulent gaseous diffusion flames. The Pt/γAl2O3 and... The Response Surface Methodology (RSM) has been applied to explore the thermal structure of the experimentally studied catalytic combustion of stabilized confined turbulent gaseous diffusion flames. The Pt/γAl2O3 and Pd/γAl2O3 disc burners were situated in the combustion domain and the experiments were performed under both fuel-rich and fuel-lean conditions at a modified equivalence (fuel/air) ratio (&oslash;) of 0.75 and 0.25 respectively. The thermal structure of these catalytic flames developed over the Pt and Pd disc burners were inspected via measuring the mean temperature profiles in the radial direction at different discrete axial locations along the flames. The RSM considers the effect of the two operating parameters explicitly (r), the radial distance from the center line of the flame, and (x), axial distance along the flame over the disc, on the measured temperature of the flames and finds the predicted maximum temperature and the corresponding process variables. Also the RSM has been employed to elucidate such effects in the three and two dimensions and displays the location of the predicted maximum temperature. 展开更多
关键词 Catalytic Combustion FUEL Lean/Fuel rich NOBLE Metals Burners Thermal Structure modeling Response Surface Method
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Forecast of the Luminescent Phenomena of Silicon Rich Oxide Films off Stoichiometry by Means of the Global Reaction Model
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作者 Néstor David Espinosa-Torres José álvaro David Hernández de la Luz +3 位作者 José Francisco Javier Flores-Gracia José Alberto Luna-López Javier Martínez-Juárez Gregorio Flores-Carrasco 《Journal of Modern Physics》 2015年第11期1679-1694,共16页
The Global Reaction Model describes a set of chemical reactions that can potentially occur during the process of obtaining silicon rich oxide (SRO) films, regardless of the technique used to grow such films which are ... The Global Reaction Model describes a set of chemical reactions that can potentially occur during the process of obtaining silicon rich oxide (SRO) films, regardless of the technique used to grow such films which are an outside stoichiometry material. Particularly, chemical reactions that occur during the process of growing of SRO films by LPCVD technique are highlighted in this model. We suggest and evaluate either some types of molecules or resulting nanostructures and we predict theoretically, by applying the density functional theory, the contribution that they may have to the phenomenon of luminescence which is measured in SRO films. Also, we have calculated the opto-electronic properties of SRO films. The suggested model provides enough information required to identify the molecular structures resulting from the presence of defects in SRO films and also those corresponding to charged structures. It is also possible to detect the molecular structures which are modified due to the effect of heat treatment, and identify the presence of different oxidation states inclusive the formation of siloxanes. 展开更多
关键词 GLOBAL Reactions model SILICON rich-Oxide Defects LPCVD Luminescence
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基于RICH模型的护理硕士研究生专门用途英语课程教学的研究 被引量:4
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作者 张姮 金胜姬 杜世正 《护理学杂志》 CSCD 北大核心 2018年第17期71-73,共3页
目的改革护理硕士研究生专门用途英语(ESP)课程教学方法,提高教学质量。方法对2016、2017级共57名护理硕士研究生,实施基于RICH模型构建的ESP课程教学,包括设置7个研究性学习主题(R)、设计整合性课程内容(I),采用合作性学习方法(C),综... 目的改革护理硕士研究生专门用途英语(ESP)课程教学方法,提高教学质量。方法对2016、2017级共57名护理硕士研究生,实施基于RICH模型构建的ESP课程教学,包括设置7个研究性学习主题(R)、设计整合性课程内容(I),采用合作性学习方法(C),综合评价学习效果(H)及课程反思。结果学生ESP课程成绩及格率均为100%,96.5%的学生对ESP课程及学习方式非常满意。结论基于RICH模型的ESP课程教学可提高教学效果,且学生反馈积极。 展开更多
关键词 护理硕士研究生 专门用途英语 课程改革 rich模型 护理教学
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RICH教学学生学习档案评估模式研究 被引量:21
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作者 黄爱凤 《浙江师范大学学报(社会科学版)》 2004年第1期79-83,共5页
本文对浙江师范大学外国语学院综合英语课RICH教学学生学习档案评估模式进行了探讨。简述了该模式产生的背景、理论及其内涵;解释了RICH学生学习档案评价模式的建构内容;分析了RICH学生自我评价的文本样例及RICH教师对该评价模式的反思... 本文对浙江师范大学外国语学院综合英语课RICH教学学生学习档案评估模式进行了探讨。简述了该模式产生的背景、理论及其内涵;解释了RICH学生学习档案评价模式的建构内容;分析了RICH学生自我评价的文本样例及RICH教师对该评价模式的反思。认为运用学习档案的评价方式实际上就把区分好坏的评价机制转变为一种促进学生自主反思的学习机制。 展开更多
关键词 学生学习档案 评估机制 rich 评估标准 课程目标
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RICH理念在高职ESP课程设计中的应用研究——以眼镜行业英语为例 被引量:1
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作者 蔡景界 《浙江工贸职业技术学院学报》 2015年第1期15-18,共4页
在ESP课程设计需求分析理论的指导下,通过调查数据分析,说明了高职院校眼镜设计与贸易专业学生学习眼镜行业英语课程的必要性。同时提出了融合RICH教学实践的眼镜行业英语课程设计模型。该模型适合在行业英语教学中应用来提高学生学习... 在ESP课程设计需求分析理论的指导下,通过调查数据分析,说明了高职院校眼镜设计与贸易专业学生学习眼镜行业英语课程的必要性。同时提出了融合RICH教学实践的眼镜行业英语课程设计模型。该模型适合在行业英语教学中应用来提高学生学习的主动性,推动高职英语教学改革。 展开更多
关键词 rich ESP 课程设计 高职 眼镜行业
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一种遵循RichClub现象的网络拓扑模型 被引量:2
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作者 李莹 张大方 《计算机工程与科学》 CSCD 2005年第4期73-75,共3页
基于现有的AS网络拓扑生成模型,本文提出了一个遵循 Rich Club现象的新网络拓扑模型。该模型不仅保正反映AS网络的基本性质,还能满足AS网络所有的特性Rich Club现象。仿真结果表明,本文的模型和算法是有效的。
关键词 因特网 网络拓扑模型 rich-Club现象 网络生成器 消息交换机制
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RICH教学模式在非英语专业的可行性初探 被引量:2
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作者 高翠英 毛永泉 《山西警官高等专科学校学报》 2013年第1期87-89,共3页
RICH教学模式是以人文主义为指导思想,以小型学生课题研究为基础,以合作式为主要学习方式,以达到提高学生运用英语的综合能力和人文素质为主要目标。此模式在非英语专业综合英语实施,可以取得明显成效。
关键词 rich教学模式 综合英语 语言环境 学习策略
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Production of heavy neutron-rich nuclei with radioactive beams in multinucleon transfer reactions 被引量:9
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作者 Cheng Li Peiwei Wen +3 位作者 Jingjing Li Gen Zhang Bing Li Feng-Shou Zhang 《Nuclear Science and Techniques》 SCIE CAS CSCD 2017年第8期97-102,共6页
The production mechanism of heavy neutronrich nuclei is investigated by using the multinucleon transfer reactions of ^(136;148)Xe+^(208)Pb and ^(238)U+^(208)Pb in the framework of a dinuclear system model. The evapora... The production mechanism of heavy neutronrich nuclei is investigated by using the multinucleon transfer reactions of ^(136;148)Xe+^(208)Pb and ^(238)U+^(208)Pb in the framework of a dinuclear system model. The evaporation residual cross sections of target-like fragments are studied with the reaction system ^(148)Xe+^(208)Pb at near barrier energies. The results show that the final isotopic production cross sections in the neutron-deficient side are very sensitive to incident energy while it is not sensitive in the neutron-rich side. Comparing the isotopic production cross sections for the reactions of ^(208)Pb bombarded with stable and radioactive projectiles, we find that neutron-rich radioactive beams can significantly increase the production cross sections of heavy neutron-rich nuclei. 展开更多
关键词 多核子转移反应 重丰中子核 生产机制 放射性 蒸发剩余截面 同位素生产 入射能量 模型框架
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Salt-Gathering and Potassium Formation of Potassium-Rich Brine during the Triassic in the Sichuan Basin, China 被引量:5
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作者 ZHANG Bing YANG Kai +6 位作者 WANG Xuben XU Zhengqi YANG Hongyu ZHANG Saimin CHEN Jinchao ZHANG Mingming LIU Wei 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2018年第6期2233-2250,共18页
Potassium-rich brine in the Sichuan Basin has been much studied in recent years, but few studies have focused on the distribution and migration of salt basin and the differences of potassium formation mechanisms. This... Potassium-rich brine in the Sichuan Basin has been much studied in recent years, but few studies have focused on the distribution and migration of salt basin and the differences of potassium formation mechanisms. This work examined the salt-gathering and potassium formation of potassiumrich brine during the Triassic in the Sichuan Basin using lithofacies palaeogeographic depiction and geochemical analyses.(1) The favorable sedimentary facies controlling the formation of potassium-rich brine during the Triassic in the Sichuan Basin are evaporation platform and restricted platform, whereas the salt basin is one of the main factors controlling the poly-salt center.(2) The distribution and migration of this salt basin were affected by certain factors. The salt basin of the Jialingjiang Formation was mainly distributed in the east and central Sichuan Basin, whereas that of the Leikoupo Formation was mainly distributed in the central and west Sichuan Basin. The sedimentary centers have gradually moved westward and become smaller.(3) Three main formation mechanisms were identified for the potassium-rich brine during the Triassic in the Sichuan Basin, i.e., evaporation and concentration of seawater, surface fresh water leaching, and deep water-rock reaction. Fresh water leaching was characterized by low anomaly δ18 O and δ13 C values. Water-rock reaction was mainly related to temperature, and high temperature environment(caused by burial depth, overthrust and deep hydrothermal fluids) was beneficial to water-rock reaction. The characteristics of water-rock reaction do not correspond to the increase ratio of K·103/Cl and Br·103/Cl in brine, and the Rb+ content of the brine was high.(4) The formation mechanisms of potassium-rich brine differed between different areas of the Sichuan Basin. In east Sichuan, the evaporation and concentration of seawater, together with meteoric fresh water leaching, was the main formation factor, whereas the evaporation and concentration of seawater and water–rock reaction predominated in west Sichuan. This study of the sedimentary environment and formation mechanisms is of significance to the exploration and exploitation of potassium-rich brine in the Sichuan Basin. 展开更多
关键词 potassium-rich brine sedimentary environment formation mechanism evolution model Sichuan Basin
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Density fluctuations in baryon-rich quark matter
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作者 Che Ming Ko Feng Li 《Nuclear Science and Techniques》 SCIE CAS CSCD 2016年第6期17-24,共8页
At finite baryon chemical potential,the density of a quark matter develops large fluctuations when it undergoes a first-order phase transition.Based on the transport equation derived from the Nambu–Jona-Lasinio(NJL) ... At finite baryon chemical potential,the density of a quark matter develops large fluctuations when it undergoes a first-order phase transition.Based on the transport equation derived from the Nambu–Jona-Lasinio(NJL) model,we have studied the density fluctuations in a baryon-rich quark matter that is confined in a finite volume.Allowing the expansion of the quark matter using initial conditions from either a blast wave model or a multiphase transport(AMPT) model,we have further studied the survivability of the density fluctuations as the density and temperature of the quark matter decrease.Possible experimental signatures of the density fluctuations are suggested. 展开更多
关键词 密度涨落 夸克物质 重子 输运方程 一级相变 体积密度 AMPT 可生存性
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基于预测农作物Se含量构建富硒土地质量评价体系——以湖南龙山县为例 被引量:2
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作者 张俊 戴亮亮 +7 位作者 巩浩 彭志刚 许青阳 胡向荣 贺灿 吴文彬 陈伟 曾剑 《中国地质》 北大核心 2025年第1期362-371,共10页
【研究目的】硒(Se)是人体必需的微量元素之一。富硒土地和富硒农产品的开发利用成为了乡村振兴的重要实践,但仅根据土壤Se含量难以准确地指导地方政府进行富硒土地资源开发。【研究方法】本文以湖南省龙山县西北部作为研究区,基于1∶50... 【研究目的】硒(Se)是人体必需的微量元素之一。富硒土地和富硒农产品的开发利用成为了乡村振兴的重要实践,但仅根据土壤Se含量难以准确地指导地方政府进行富硒土地资源开发。【研究方法】本文以湖南省龙山县西北部作为研究区,基于1∶50000土地质量地球化学调查数据和全国土地调查成果数据探讨了水稻Se生物富集系数的影响因素,并据此建立了水稻籽实Se含量多元线性回归预测模型,结合耕地地力和环境质量提出了富硒土地质量评价体系。【研究结果】(1)研究区土壤Se含量为0.19~0.84 mg/kg,平均值0.48 mg/kg,水稻籽实Se含量为0.02~0.23 mg/kg,平均值0.10 mg/kg,水稻籽实富硒率为83%。(2)水稻籽实Se生物富集系数与土壤Cd、S和TC呈极显著负相关关系,相关系数分别−0.617、−0.452和−0.574。(3)区划结果显示,研究区以无公害富硒中高产耕地为主,面积占比78%,无公害中高产耕地和无公害低产耕地面积相对较小,面积分别占13%和4%;安全利用富Se耕地和谨慎利用耕地面积分别占4%和1%。【结论】在科学预测农作物籽实Se元素含量的基础上,本文构建了一种基于农作物富Se水平、耕地地力和环境质量的地块尺度富Se土地质量评价体系,对地方政府进行富Se土地资源开发利用具有重要参考示范意义。 展开更多
关键词 富Se水稻 预测模型 富硒土地 区划方法 土壤地球化学调查工程 龙山县 湖南省
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Hydrocarbon-Generating Characteristics of Barkinite-Rich Coals from Late Permian Longtan Formation, South China 被引量:1
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作者 孙旭光 《Chinese Journal Of Geochemistry》 EI CAS 2000年第3期227-232,共6页
Leping coal (including barkinite\|rich coal) is a unique kind of coal, which is widely distributed in the Late Permian Longtan Formation, South China. In this paper, Rock\|Eval, Py\|GC and simulation experiment via an... Leping coal (including barkinite\|rich coal) is a unique kind of coal, which is widely distributed in the Late Permian Longtan Formation, South China. In this paper, Rock\|Eval, Py\|GC and simulation experiment via an open\|system were used to study the hydrocarbon\|generating potential, hydrocarbon composition, and hydrocarbon\|generating model of barkinite\|rich coals from the Shuicheng coal field of Guizhou Province, Southwest China. The results show that barkinite\|rich coals have high hydrocarbon\|generating potential, with S\-1+S\-2 being 211-311mg/g, and can produce large amounts of hydrocarbon at the high\|maturity stage, mostly within the temperature range of 420-450℃ (corresponding to VR\-0 1.1-1.5%); barkinite\|rich coal is one of the better oil sources and light hydrocarbon and wet gas are the major hydrocarbon components, which account for 45% and 33% of the total hydrocarbons, respectively. These characteristics are of importance for exploring oil and gas resources in the Late Permian Longtan Formation coals, Southwest China.\; 展开更多
关键词 西南地区 中国 碳氢化合物 势能 成困 煤矿床
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Response Surface Methodology and Artificial Neural Network Methods Comparative Assessment for Fuel Rich and Fuel Lean Catalytic Combustion 被引量:1
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作者 Tahani S. Gendy Amal S. Zakhary Salwa A. Ghoneim 《World Journal of Engineering and Technology》 2021年第4期816-847,共32页
Modeling, predictive and generalization capabilities of response surface methodology (RSM) and artificial neural network (ANN) have been performed to assess the thermal structure of the experimentally studied cat... Modeling, predictive and generalization capabilities of response surface methodology (RSM) and artificial neural network (ANN) have been performed to assess the thermal structure of the experimentally studied catalytic combustion of stabilized confined turbulent gaseous diffusion flames. The Pt/<i>γ</i>Al<sub>2</sub>O<sub>3</sub> and Pd/<i>γ</i>Al<sub>2</sub>O<sub>3</sub> disc burners were located in the combustion domain and the experiments were accomplished under both fuel-rich and fuel-lean conditions at a modified equivalence (fuel/air) ratio (<i><span style="white-space:nowrap;"><span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">&oslash;</span></span></i>) of 0.75 and 0.25, respectively. The thermal structure of these catalytic flames developed over the Pt and Pd disc burners w<span style="white-space:normal;font-family:;" "="">as</span><span style="white-space:normal;font-family:;" "=""> scrutinized via measuring the mean temperature profiles in the radial direction at different discrete axial locations along with the flames. The RSM and ANN methods investigated the effect of the two operating parameters namely (<i>r</i>), the radial distance from the center line of the flame, and (<i>x</i>), axial distance along with the flame over the disc, on the measured temperature of the flames and predicted the corresponding temperatures beside predicting the maximum temperature and the corresponding input process variables. A three</span><span style="white-space:normal;font-family:;" "="">-</span><span style="white-space:normal;font-family:;" "="">layered Feed Forward Neural Network was developed in conjugation with the hyperbolic tangent sigmoid (tansig) transfer function and an optimized topology of 2:10:1 (input neurons:hidden neurons:output neurons). Also the ANN method has been exploited to illustrate </span><span style="white-space:normal;font-family:;" "="">the </span><span style="white-space:normal;font-family:;" "="">effects of coded <i>R</i> and <i>X</i> input variables on the response in the three and two dimensions and to locate the predicted maximum temperature. The results indicated the superiority of ANN in the prediction capability as the ranges of  & F_Ratio are 0.9181</span><span style="white-space:normal;font-family:;" "=""> </span><span style="white-space:normal;font-family:;" "="">- 0.9809 & 634.5</span><span style="white-space:normal;font-family:;" "=""> </span><span style="white-space:normal;font-family:;" "="">- 3528.8 for RSM method compared to 0.9857</span><span style="white-space:normal;font-family:;" "=""> </span><span style="white-space:normal;font-family:;" "="">- 0.9951 & 7636.4</span><span style="white-space:normal;font-family:;" "=""> </span><span style="white-space:normal;font-family:;" "="">- 24</span><span style="white-space:normal;font-family:;" "="">,</span><span style="white-space:normal;font-family:;" "="">028.4 for ANN method beside lower values </span><span style="white-space:normal;font-family:;" "="">for error analysis terms.</span> 展开更多
关键词 Catalytic Combustion Fuel Lean/Fuel rich Noble Metals Burners Thermal structure modelING Artificial Neural Network Response Surface Methodology Feed Forward Neural Network
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基于富语义词元的大模型生成策略优化
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作者 程齐凯 石湘 +1 位作者 于丰畅 黄圣智 《情报学报》 北大核心 2025年第6期761-782,共22页
近年来,通用大模型技术取得了显著进展,但在科技情报领域的应用中,仍面临推理效率低下和领域任务适配性不足的问题。为此,本文系统地分析了大模型的生成机制,并提出了“富语义词元”概念,旨在描述大模型在生成过程中倾向产生的、具有语... 近年来,通用大模型技术取得了显著进展,但在科技情报领域的应用中,仍面临推理效率低下和领域任务适配性不足的问题。为此,本文系统地分析了大模型的生成机制,并提出了“富语义词元”概念,旨在描述大模型在生成过程中倾向产生的、具有语义聚合性、上下文依赖性或任务相关性的词元或词元序列。基于该概念,本文设计了一种基于生成偏好的大小模型协同生成策略。通过富语义词元的挖掘、复制机制及动态验证策略,实现在小模型与大模型之间的协同作用,推动大模型由逐词元生成向多个词元同步生成的转变,从而提升生成效率与任务适配性。本文从生成性能、泛用性和生成效率三个维度对该生成优化策略进行了评估。研究结果表明,该策略在法律、医学和新闻百科等多个领域任务中的评估指标均优于传统生成优化方法。本文为大模型生成优化、任务适配性提升以及可信可靠大模型构建提供了新的理论基础和实践路径。 展开更多
关键词 富语义词元 大小模型协同 生成优化 动态投机采样
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青藏高原富水冰碛隧道施工安全韧性评价方法
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作者 樊燕燕 马茗 刘轩谷 《铁道科学与工程学报》 北大核心 2025年第8期3715-3728,共14页
为提高隧道施工安全水平,解决当前青藏高原富水冰碛隧道施工中安全隐患大、事故频发的问题,引入韧性理论,提出一种施工安全韧性评价方法。首先对青藏高原富水冰碛隧道施工安全韧性的概念进行分析,结合PSR(pressure-state-response)模型... 为提高隧道施工安全水平,解决当前青藏高原富水冰碛隧道施工中安全隐患大、事故频发的问题,引入韧性理论,提出一种施工安全韧性评价方法。首先对青藏高原富水冰碛隧道施工安全韧性的概念进行分析,结合PSR(pressure-state-response)模型,建立青藏高原富水冰碛隧道施工安全韧性PSR模型,在此基础上,通过系统性文献综述法和专家调查法识别并筛选指标,建立了包含3个1级指标和26个2级指标的青藏高原富水冰碛隧道施工安全韧性评价指标体系;其次,基于博弈论原理,运用区间层次分析法和反熵权法,求得指标最优组合权重,并运用可拓云综合评价模型,将定量与定性分析相结合,对青藏高原富水冰碛隧道施工安全韧性进行评价;最后,对青藏高原地区某富水冰碛隧道的施工安全韧性进行了实例分析,并从压力指标、状态指标、响应指标3方面提出韧性提升建议。研究结果表明:该隧道施工安全韧性等级为3级(中等韧性),其中压力指标的韧性等级为2级(较低韧性),状态指标的韧性等级为4级(较高韧性),响应指标的韧性等级为3级(中等韧性),说明该隧道施工过程中受到压力因素的影响较为严重,但依靠施工系统自身完善有效的措施方案,能在很大程度上吸收冲击扰动,并恢复正常施工。研究成果可为当前青藏高原富水冰碛隧道施工安全韧性评价提供一种有效的量化方法,为此类项目施工韧性的提升提供参考。 展开更多
关键词 富水冰碛隧道 PSR 可拓云模型 韧性评价 施工安全
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