期刊文献+
共找到4,081篇文章
< 1 2 205 >
每页显示 20 50 100
Whole Perfect Vectors and Fermat’s Last Theorem
1
作者 Ramon Carbó-Dorca 《Journal of Applied Mathematics and Physics》 2024年第1期34-42,共9页
A naïve discussion of Fermat’s last theorem conundrum is described. The present theorem’s proof is grounded on the well-known properties of sums of powers of the sine and cosine functions, the Minkowski norm de... A naïve discussion of Fermat’s last theorem conundrum is described. The present theorem’s proof is grounded on the well-known properties of sums of powers of the sine and cosine functions, the Minkowski norm definition, and some vector-specific structures. 展开更多
关键词 Fermat’s last Theorem Whole Perfect Vectors Sine and Cosine Functions Natural and Rational Vectors Fermat Vectors
下载PDF
Situational Analysis of Malaria Control Following the 2021 Distribution of Long Lasting Insecticide-Treated Bed Nets in the Tiko Health District, South West Region, Cameroon
2
作者 Jini Victor Bongajum Nyasa Raymond Babila Esum Mathias Eyong 《Journal of Biosciences and Medicines》 2023年第4期153-172,共20页
Malaria is still a major public health concern in Cameroon as more than 20 million people are at risk of the disease. Despite the government’s effort to scale up the distribution of long lasting insecticide-treated b... Malaria is still a major public health concern in Cameroon as more than 20 million people are at risk of the disease. Despite the government’s effort to scale up the distribution of long lasting insecticide-treated bed nets (LLINs), full ownership and optimal use is still limited. In 2021, over a million LLINs were made available for distribution in the South West Region. However, the current situation of malaria has not yet been ascertained following the 2021 mass distribution campaign (MDC). Therefore, the aim of this study was to determine LLIN ownership, coverage, usage and the prevalence of malaria following the 2021 MDC in the Tiko Health District (THD), South West Region of Cameroon. A cross-sectional study was carried from May 1 to 27, 2022 in which a multi-stage sampling technique was used to enroll eligible participants. Data were collected from household heads using questionnaires and capillary blood samples collected from consented household members were used to test for malaria. Data were analyzed using SPSS version 25 at 0.05 significance level. From the 150 households surveyed, 96 (64.0%) owned a mosquito net before the recent MDC. There was an overall significant increase (p p = 0.644) in LLINs ownership between areas where door-to-door (79.5%) and fixed “Hit and Run” (75.8%) strategies were used in the distribution of LLINs in THD. The prevalence of malaria was 10.2%. The regular use of LLINs was significantly associated (p = 0.007) with low malaria prevalence. The 2021 MDC had an impact on malaria prevalence in those who properly used them. 展开更多
关键词 Long lasting Insecticide Treated-Bed Nets OWNERSHIP COVERAGE Use Malaria Prevalence
下载PDF
Products of Odd Numbers or Prime Number Can Generate the Three Members’ Families of Fermat Last Theorem and the Theorem Is Valid for Summation of Squares of More Than Two Natural Numbers
3
作者 Susmita Pramanik Deepak Kumar Das Panchanan Pramanik 《Advances in Pure Mathematics》 2023年第10期635-641,共7页
Fermat’s last theorem, had the statement that there are no natural numbers A, B, and C such that A<sup>n</sup> + B<sup>n</sup> = C<sup>n</sup>, in which n is a natural number great... Fermat’s last theorem, had the statement that there are no natural numbers A, B, and C such that A<sup>n</sup> + B<sup>n</sup> = C<sup>n</sup>, in which n is a natural number greater than 2. We have shown that any product of two odd numbers can generate Fermat or Pythagoras triple (A, B, C) following n = 2 and also it is applicable A<sup>2</sup> + B<sup>2</sup> + C<sup>2</sup> + D<sup>2</sup> + so on =A<sub>n</sub><sup>2 </sup>where all are natural numbers. 展开更多
关键词 Fermat last Theorem Generation of Fermat’s Numbers Extension of Fermat’s Expression Fermat’s Expression from Products of Odd Numbers
下载PDF
On Fermat Last Theorem: The New Efficient Expression of a Hypothetical Solution as a Function of Its Fermat Divisors
4
作者 Prosper Kouadio Kimou 《American Journal of Computational Mathematics》 2023年第1期82-90,共9页
Denote by a non-trivial primitive solution of Fermat’s equation (p prime).We introduce, for the first time, what we call Fermat principal divisors of the triple defined as follows. , and . We show that it is possible... Denote by a non-trivial primitive solution of Fermat’s equation (p prime).We introduce, for the first time, what we call Fermat principal divisors of the triple defined as follows. , and . We show that it is possible to express a,b and c as function of the Fermat principal divisors. Denote by the set of possible non-trivial solutions of the Diophantine equation . And, let<sub></sub><sub></sub> (p prime). We prove that, in the first case of Fermat’s theorem, one has . In the second case of Fermat’s theorem, we show that , ,. Furthermore, we have implemented a python program to calculate the Fermat divisors of Pythagoreans triples. The results of this program, confirm the model used. We now have an effective tool to directly process Diophantine equations and that of Fermat. . 展开更多
关键词 Fermat’s last Theorem Fermat Divisors Barlow’s Relations Greatest Common Divisor
下载PDF
Unfavorable environmental conditions for tropical cyclone genesis over the western North Pacific during the Last Interglacial based on PMIP4 simulations
5
作者 Dubin Huan Qing Yan Ting Wei 《Atmospheric and Oceanic Science Letters》 CSCD 2023年第5期68-74,共7页
研究过去暖期西北太平洋热带气旋的变化有助于理解未来气候变暖情景下热带气旋的可能变化.本研究基于PMIP4多模式输出结果,分析了末次间冰期西北太平洋热带气旋大尺度生成因子的变化及相关机制.结果表明,末次间冰期西北太平洋风暴季潜... 研究过去暖期西北太平洋热带气旋的变化有助于理解未来气候变暖情景下热带气旋的可能变化.本研究基于PMIP4多模式输出结果,分析了末次间冰期西北太平洋热带气旋大尺度生成因子的变化及相关机制.结果表明,末次间冰期西北太平洋风暴季潜在强度降低,湿熵亏损升高,绝对涡度减弱,中部垂直风切变增强,西南部减弱.进一步,基于生成潜势指数,指出末次间冰期西北太平洋生成潜势降低,这表明环境条件不利于热带气旋生成。 展开更多
关键词 热带气旋 末次间冰期 PMIP4
下载PDF
Strength of the North African monsoon in the Last Interglacial and under future warming
6
作者 Jiazhi He Weiyi Sun +2 位作者 Jing Wang Bin Wang Jian Liu 《Atmospheric and Oceanic Science Letters》 CSCD 2023年第3期20-26,共7页
与人为强迫引起的全球变暖相比,末次间冰期是轨道强迫引起的过去80万年来最暖的一个间冰期,但鲜有人研究末次间冰期中北非季风的响应.因此,本文基于CMIP6多模式模拟结果对比研究了末次间冰期和SSP5-8.5情景下北非季风的响应,发现末次间... 与人为强迫引起的全球变暖相比,末次间冰期是轨道强迫引起的过去80万年来最暖的一个间冰期,但鲜有人研究末次间冰期中北非季风的响应.因此,本文基于CMIP6多模式模拟结果对比研究了末次间冰期和SSP5-8.5情景下北非季风的响应,发现末次间冰期下北非季风平均降水及其降水变率均远大于SSP5-8.5情景下的结果.轨道强迫导致的北大西洋暖于南大西洋增加了北非季风环流和平均降水,同时,南北大西洋海温梯度变化通过增强热带北大西洋的海气相互作用增大了海温梯度和撒哈拉低压的变率,从而增强了北非季风降水变率. 展开更多
关键词 北非季风 降水变率 末次间冰期 全球变暖
下载PDF
Can a global mean sea-level rise reduce the Last Interglacial model-data mismatch in East Asia?
7
作者 Zhiqi Qian Tianao Xu +1 位作者 Zhongshi Zhang Chunju Huang 《Atmospheric and Oceanic Science Letters》 CSCD 2023年第5期121-128,共8页
末次间冰期有着丰富的重建和模拟资料,为研究未来温暖气候提供了一个理想的参考.然而,关于末次间冰期的东亚气候,模拟与重建的结果间长期存在着不匹配的情况,模拟结果普遍较重建结果更为冷干。本研究利用挪威地球系统模式(NorESM1-F),... 末次间冰期有着丰富的重建和模拟资料,为研究未来温暖气候提供了一个理想的参考.然而,关于末次间冰期的东亚气候,模拟与重建的结果间长期存在着不匹配的情况,模拟结果普遍较重建结果更为冷干。本研究利用挪威地球系统模式(NorESM1-F),探讨了在末次间冰期模拟试验中纳入全球平均海平面上升能否减少模式-数据的不匹配.该试验结果表明,海平面上升情况下东亚地区会产生一定的增温增湿效应,但不足以消除模式-数据不匹配.基于这些结果,作者探讨了其它可能造成不匹配的因素以供进一步研究. 展开更多
关键词 末次间冰期 海平面上升 模式-数据不匹配
下载PDF
ACE、CICARE及LAST护理服务理念在脑梗死患者康复护理中的应用效果 被引量:10
8
作者 张燕琴 李晓萍 +1 位作者 孔维维 范东英 《西部中医药》 2019年第11期122-124,共3页
目的:观察ACE、CICARE及LAST护理服务在脑梗死患者康复护理中的应用效果。方法:将脑梗死恢复期患者60例随机分为观察组和对照组各30例。对照组行常规护理,观察组在对照组基础上行ACE、CICARE及LAST护理服务,比较2组患者护理满意度、Bart... 目的:观察ACE、CICARE及LAST护理服务在脑梗死患者康复护理中的应用效果。方法:将脑梗死恢复期患者60例随机分为观察组和对照组各30例。对照组行常规护理,观察组在对照组基础上行ACE、CICARE及LAST护理服务,比较2组患者护理满意度、Barthel指数、护理依从性、回归社会生活信心等心理状况。结果:观察组护理满意度、Barthel指数、护理治疗依从性、对回归社会生活的信心及心理状况优于对照组,差异具有统计学意义(P<0.05)。结论:ACE、CICARE及LAST护理服务有利于提高脑梗死患者临床康复护理满意度,提高患者慢病自我管理能力,增加护理治疗依从性及患者回归社会生活的信心,减少焦虑及抑郁情绪等心理状况的发生。 展开更多
关键词 脑梗死 ACE CICARE last 护理服务理念 临床护理
下载PDF
LAST理论与外语教学 被引量:4
9
作者 刘振前 张秀丽 《西安外国语学院学报》 2003年第4期4-9,共6页
本文简要介绍了最新的语言加工模式后句法指派理论 ,并探讨了这一理论对外语教学的启示。L AST认为 ,语言理解是联想与符号计算两种过程的组合 ,人在理解过程中首先根据输入的表层线索形成意义 /形式假设 ,即假句法 ,然后根据句法规则... 本文简要介绍了最新的语言加工模式后句法指派理论 ,并探讨了这一理论对外语教学的启示。L AST认为 ,语言理解是联想与符号计算两种过程的组合 ,人在理解过程中首先根据输入的表层线索形成意义 /形式假设 ,即假句法 ,然后根据句法规则生成完整的结构 ,并与输入序列进行对比 ,如果相符 ,则将结果存储到概念记忆中 ,进入下一句的理解。反之 ,则重复上述过程。句子是理解过程中联想信息和符号信息融合的自然层次。大量的研究证据无疑都支持上述理论 ,而且用这种理论可以更好地解释以前难以解释的一些心理语言学现象。同时 ,该理论对我们重新审视语言习得理论有重要意义 :人不同于其他动物 ,具有语言学习的能力 ,但外部刺激对语言发展起重要的作用 ,出现频率高的SVO结构先得到发展。这就为外语教学中传统教学法的应用提供了理论依据。 展开更多
关键词 last理论 英语教学 语言习得 语言理解 后句法指派理论 语法翻译法
下载PDF
基于Hadoop Streaming的Last比对软件并行化的研究与实现
10
作者 董本志 李文浩 景维鹏 《计算机工程与应用》 CSCD 2014年第2期226-230,共5页
随着下一代测序技术的到来,单机版Last比对软件已经不能满足海量数据的处理需求。使用Hadoop Streaming技术将Last比对软件快速部署到云计算环境中,解决当前单机版Last比对软件处理大数据能力差的问题。通过自定义的基于NFS文件系统的... 随着下一代测序技术的到来,单机版Last比对软件已经不能满足海量数据的处理需求。使用Hadoop Streaming技术将Last比对软件快速部署到云计算环境中,解决当前单机版Last比对软件处理大数据能力差的问题。通过自定义的基于NFS文件系统的数据集切分方法和基于Partitioner的任务分配方式能够实现均衡高效的数据切分,并保证并行化粒度可控。实验结果表明,在保证与单机运行结果一致的情况下,这种方法能有效缩减软件运行时间,具有较高的加速比。 展开更多
关键词 HADOOP STREAMING 软件并行化 last比对软件
下载PDF
书信中语篇人际意义的实现——从对“A Soldier’s Last Letter”语言的分析谈起 被引量:1
11
作者 赵青 郭英杰 《陕西教育学院学报》 2008年第4期88-92,共5页
结合功能语言学理论,以"A Soldier’s Last Letter"中的部分段落为例进行分析,可以展示如何通过语气系统和情态系统来进行选择形成语篇,从而突显语言选择对语篇人际意义实现的重要性以及功能语言学在分析文学作品时的可行性。
关键词 A Soldier’s last LETTER 人际功能 语气 情态
下载PDF
Very Original Proofs of Two Famous Problems: “Are There Any Odd Perfect Numbers?” (Unsolved until to Date) and “Fermat’s Last Theorem: A New Proof of Theorem (Less than One and a Half Pages) and Its Generalization” 被引量:2
12
作者 Demetrius Chr. Poulkas 《Advances in Pure Mathematics》 2021年第11期891-928,共38页
This article presents very original and relatively brief or very brief proofs about of two famous problems: 1) Are there any odd perfect numbers? and 2) “Fermat’s last theorem: A new proof of theorem and its general... This article presents very original and relatively brief or very brief proofs about of two famous problems: 1) Are there any odd perfect numbers? and 2) “Fermat’s last theorem: A new proof of theorem and its generalization”. They are achieved with elementary mathematics. This is why these proofs can be easily understood by any mathematician or anyone who knows basic mathematics. Note that, in both problems, proof by contradiction was used as a method of proof. The first of the two problems to date has not been resolved. Its proof is completely original and was not based on the work of other researchers. On the contrary, it was based on a simple observation that all natural divisors of a positive integer appear in pairs. The aim of the first work is to solve one of the unsolved, for many years, problems of the mathematics which belong to the field of number theory. I believe that if the present proof is recognized by the mathematical community, it may signal a different way of solving unsolved problems. For the second problem, it is very important the fact that it is generalized to an arbitrarily large number of variables. This generalization is essentially a new theorem in the field of the number theory. To the classical problem, two solutions are given, which are presented in the chronological order in which they were achieved. <em>Note that the second solution is very short and does not exceed one and a half pages</em>. This leads me to believe that Fermat, as a great mathematician was not lying and that he had probably solved the problem, as he stated in his historic its letter, with a correspondingly brief solution. <em>To win the bet on the question of whether Fermat was telling truth or lying, go immediately to the end of this article before the General Conclusions.</em> 展开更多
关键词 Perfect Numbers Odd Perfect Numbers Fermat’s last Theorem Generalization of the Fermat’s last Theorem Prime Number Problems Millennium Problems
下载PDF
China's English Learners' Verbal Phrase Acquisition Research Based on the Corpus——“at last”and“in the end”as an Example
13
作者 张俊梅 柴晶 《海外英语》 2013年第24期262-263,287,共3页
This study is a comparative research based on corpus. This article compares China's English learners with English na?tive speakers about the use of "at last" and "in the end" from three aspects... This study is a comparative research based on corpus. This article compares China's English learners with English na?tive speakers about the use of "at last" and "in the end" from three aspects: frequency of use, location, semantic prosody. The study shows that the use of the two words are greatly different between China's English learners and English native speakers. In addition, this study discusses about causes of obvious differences and teaching enlightenments. 展开更多
关键词 at last in the end" China’s English LEARNERS
下载PDF
A Post-colonial Approach to The Last of the Mohicans
14
作者 谭秀敏 《海外英语》 2013年第23期232-234,共3页
The Last of the Mohicans is one of the five frontier novels written by famous American novelist James Fenimore Cooper in the early 19thcentury.Although it has been criticized for its narrative flaws,its length and for... The Last of the Mohicans is one of the five frontier novels written by famous American novelist James Fenimore Cooper in the early 19thcentury.Although it has been criticized for its narrative flaws,its length and formal prose style,it was one of the most popular in its time and is of a high literary value nowadays.With the coming of the white European colonialists,the Indians underwent various changes.Some Indians submitted themselves to the white while some Indians rebelled against the invaders and sought their revenge.With a post-colonial approach,the changes of the Indians will be better understood,and people nowadays will also have a better understanding of the Indian history and culture in early American history. 展开更多
关键词 The last of Mohicans POST-COLONIAL THEORY COLONIAL
下载PDF
Glacier Relics of the Last Glacial and Holocene Periods Discovered in the Middle-low Mountains of Eastern China: Sedimentary Sequences and Environmental Evolution of Mengshan Mountain in Shandong Province since 80 ka 被引量:8
15
作者 WANG Zhaobo WANG Jiangyue +1 位作者 HE Lelong ZHANG Jian 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2020年第1期141-151,共11页
The goal of this research study is to describe academic issues which have been debated in the field of Chinese geosciences for a century. In 1922, Jonquei S. Lee(Li Siguang) discovered Quaternary glacial relics at Tai... The goal of this research study is to describe academic issues which have been debated in the field of Chinese geosciences for a century. In 1922, Jonquei S. Lee(Li Siguang) discovered Quaternary glacial relics at Taihang Mountainin eastern China. In 1947, he published his research findings in the magazine Mount Lushan in Glacial Age. The research results had established three Ice Ages: Poyang(Gonzi), Dagu(Minde), and Lushan(Lisi). However, at that time, no Wurm glacial relics of the last Ice Age had been found in Lushan Mountain. Since then, the research team represented by Shi Yafeng, who is considered to be "the father of glaciers in China", questioned Jonquei S. Lee’s research results and concluded that "Professor Jonquei S. Lee’s Quaternary glacier research in Lushan Mountain having misread the debris flow". In 2005, the "middle-low mountains" in eastern China were finally defined as follows: "We clearly and unambiguously believe that there were no glacial activities in the middle-low mountainous areas of eastern China(east of 102° to 104°E;below 3,000 and 2,500 m) during the Quaternary Period". Currently, the long-standing academic debate appears to have come to a conclusion. As of 2015, the author and others began to investigate and study the Quaternary glacial relics in Mengshan Mountain(1,156 m above sea level), Shandong Province, one of the "middle-low mountains" of eastern China. The relics have been observed to posses the systematic features of glacial erosion, trough and valley striations, and moraine deposits. The applied dating method shave confirmed that there were not only glacial relics of the last Ice Age(Wurm), but also Holocene glacial relics in the Mengshan Mountain area. Therefore, in order to further establish the corresponding relationship between the glacier, loess, stream sediment series, and MIS in the Mengshan Mountain area, a large number of chronological studies have been carried out regarding the various types of sediments in the area, and 24 dating datahave been obtained using OSL, CRN, and 14 Cmethods.On this basis, the corresponding relationship between the sedimentary sequences and the MIS was established for the first time in eastern China, which in dicates the environmental changes which had occurred in eastern China since 80 ka. These discoveries s and chronological study results confirm the existence of the Last Ice Age, as well as Holocene glacial relics at Mengshan Mountain, there by confirming that Quaternary glaciation had occurred in the middle-low mountain areas of eastern China. 展开更多
关键词 OSL CRN MIS GLACIAL RELICS last Ice Age HOLOCENE Eastern China
下载PDF
Climate change during the last glacial period on the southeast margin of Badain Jaran Desert, Northwest China 被引量:3
16
作者 FAN Xiao-lu ZHANG Xin-yi TIAN Ming-zhong 《Journal of Mountain Science》 SCIE CSCD 2019年第10期2379-2388,共10页
Reconstruction of the desert paleoclimate is important to understand the mechanisms that triggered and/or enhanced climate change.Through optically stimulated luminescence(OSL)dating,grain size,magnetic susceptibility... Reconstruction of the desert paleoclimate is important to understand the mechanisms that triggered and/or enhanced climate change.Through optically stimulated luminescence(OSL)dating,grain size,magnetic susceptibility,X-ray powder diffraction(XRD)and geochemical indicators,we provide a welldated record of a sedimentary outcrop on the southeast margin of the Bardain Jaran Desert,Northwest China,during the last glacial period.Four Qz-OSL ages are obtained,41.0±3.4 ka,54.7±4.4 ka,59.5±5.0 ka and 66.8±5.8 ka,corresponding to the depths of 35 cm,70 cm,150 cm and 200 cm respectively.Indicators like grain size,clay content,magnetic susceptibility,XRD and geochemical index(e.g.Sr,Ba,Sr/Ca)jointly indicate abrupt climate changes at the depth of 35 cm(age,ca.41.0 ka)and200 cm(age,ca.67 ka).Namely,the 280 cm sedimentary outcrop perfectly records a warm wet climate stage,corresponding to the late Marine Isotope Stages(MIS)4 to the early MIS 3.Besides,there is a trend of grain size increase after around 40ka BP,which is most likely a signal of wind strength change.Our research supports that enhancing Siberian High pressure system during the late MIS 3played a key role in NW East Asia climate evolution. 展开更多
关键词 last GLACIAL period Bardain Jaran DESERT Climate change Siberian High pressure system XRD
原文传递
An Analysis of Subtitling through Andre Lefevere's Rewriting Theory:A Case Study on English and Two Chinese Translations of The Last Emperor 被引量:1
17
作者 陈子婧 《疯狂英语(理论版)》 2016年第3期169-171,共3页
This paper will try to apply Andre Lefevere's rewriting theory to study subtitling.Through the analysis of The Last Emperor and its two Chinese translations,we will explore how ideology manipulates subtitle transl... This paper will try to apply Andre Lefevere's rewriting theory to study subtitling.Through the analysis of The Last Emperor and its two Chinese translations,we will explore how ideology manipulates subtitle translation. 展开更多
关键词 last Emperor Rewriting Theory SUBTITLING
下载PDF
Comparison of Climate and Environment Change of the Last Interglacial Period and Holocene in Beijing Area, China 被引量:3
18
作者 Yonggang Ge Mingjian Wei 《International Journal of Geosciences》 2014年第8期852-862,共11页
Research on climate changes between the last interglacial period and Holocene renders a speculation on the tendency of present climate. Fully understanding the nature of the changes will play a significant role in a b... Research on climate changes between the last interglacial period and Holocene renders a speculation on the tendency of present climate. Fully understanding the nature of the changes will play a significant role in a better understanding of global climate change. This work discussed the climate change of the last interglacial period and Holocene in Beijing area to discover the mechanism of local palaeo-climate change. The palaeo-vegetation of the last interglacial period in Xishan Mountain of Beijing was reconstructed by pollen analysis and thermo-luminescence dating to represent the change of palaeo-climate and palaeo-environment. Palaeo-vegetation indicators demonstrated that the climate change of the last interglacial period included 6 stages and was homologous to that reflected by the records from deep sea depositions and polar ice cores, respectively corresponding to Marine Isotope Stage (MIS) 5e, 5d, 5c, 5b, 5a and the interim from MIS5 to MIS4 from the early to the late. Millennial climate abrupt events occurred in MIS 5e, which had an agreement with the records of GRIP. In addition, a climate warming event appeared in the interim from MIS5 to MIS4 and it also was found in other regions of the world. Compared with the vegetation and environment indicators of Holocene in Beijing area, it was found that the vegetation, climate and environment of the last glacial period were better than those of Holocene. The climate abrupt events not only appeared in the last interglacial period and MIS 5e, but also occurred in Holocene, whose mechanism and pattern were analogical. After analyzing the records of millennial climate abrupt change events from this work, Ice Cores and others, it was concluded that climate was instability in the interglacial period. 展开更多
关键词 VEGETATION CLIMATE Environment last INTERGLACIAL PERIOD MIS5 HOLOCENE
下载PDF
The First Loess-Based Paleoclimatic Reconstruction over the Last Interglacial-Glacial Cycle in the Hunshandake Sandy Land 被引量:1
19
作者 JIANG Kai WANG Xisheng SHENG Mei 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2018年第3期1285-1287,共3页
Although extensive lakes and eolian sands within andsurrounding the Hunshandake Sandy Land (HSL) aresensitive to paleoenvironmental variations in arid andsemi-arid eastern Inner Mongolia (e.g., Yang et al., 2013),... Although extensive lakes and eolian sands within andsurrounding the Hunshandake Sandy Land (HSL) aresensitive to paleoenvironmental variations in arid andsemi-arid eastern Inner Mongolia (e.g., Yang et al., 2013),these records are commonly confined to the lastdeglaciation, hampering a complete understanding ofclimatic fluctuations on glacial-interglacial time scales. 展开更多
关键词 The First Loess-Based PALEOCLIMATIC Reconstruction the last Interglacial-Glacial Cycle
下载PDF
Long Lasting Phosphorescence in Eu^(2+) and Ce^(3+) Co-Doped Strontium Borate Glasses 被引量:1
20
作者 张岚 李成宇 苏锵 《Journal of Rare Earths》 SCIE EI CAS CSCD 2006年第z2期196-198,共3页
Long lasting phosphorescence (LLP) was observed in Eu2+, Ce3+ co-doped strontium borate glasses prepared under the reducing atmosphere due to the emission of both Eu2+ and Ce3+. The methods of photoluminescence, therm... Long lasting phosphorescence (LLP) was observed in Eu2+, Ce3+ co-doped strontium borate glasses prepared under the reducing atmosphere due to the emission of both Eu2+ and Ce3+. The methods of photoluminescence, thermoluminescence and phosphorescence were used to study the samples, and possible mechanism was suggested. The co-doping of Ce3+ ions poisoned the phosphorescence emission of Eu2+ because of the competition to obtain the trapped electron. The phosphorescence of Ce3+ in the sample decays more quickly than that of Eu2+, which is suggested for the reason that the emission energy of Ce3+ is higher or the distance between Ce3+ and electron traps of the glasses is longer. 展开更多
关键词 LONG lasting PHOSPHORESCENCE STRONTIUM BORATE glasses Eu2+ Ce3+ rare earths
下载PDF
上一页 1 2 205 下一页 到第
使用帮助 返回顶部