期刊文献+
共找到14篇文章
< 1 >
每页显示 20 50 100
Systematics of the avian family Alaudidae using multilocus and genomic data
1
作者 Per Alstrom Zeinolabedin Mohammadi +9 位作者 Erik D.Enbody Martin Irestedt Derek Engelbrecht Pierre-Andre Crochet Alban Guillaumet Loïs Rancilhac B.Irene Tieleman Urban Olsson Paul F.Donald Martin Stervander 《Avian Research》 SCIE CSCD 2023年第2期137-152,共16页
The family Alaudidae,larks,comprises 93-100 species(depending on taxonomy)that are widely distributed across Africa and Eurasia,with single species extending their ranges to North and northernmost South America and Au... The family Alaudidae,larks,comprises 93-100 species(depending on taxonomy)that are widely distributed across Africa and Eurasia,with single species extending their ranges to North and northernmost South America and Australia.A decade-old molecular phylogeny,comprising~80%of the species,revealed multiple cases of parallel evolution and large variation in rates of morphological evolution,which had misled taxonomists into creating many non-monophyletic genera.Here,we reconstruct the phylogeny of the larks,using a dataset covering one mitochondrial and 16 nuclear loci and comprising all except one of the currently recognised species as well as several recently proposed new species(in total 133 taxa;not all loci available for all species).We provide additional support using genome-wide markers to infer a genus-level phylogeny based on near-complete generic sampling(in total 51 samples of 44 taxa across 40 species).Our results confirm the previous findings of rampant morphological convergence and divergence,and reveal new cases of paraphyletic genera.We propose a new subfamily classification,and also that the genus Mirafra is divided into four genera to produce a more balanced generic classification of the Alaudidae.Our study supports recently proposed species splits as well as some recent lumps,while also questioning some of the latter.This comprehensive phylogeny will form an important basis for future studies,such as comparative studies of lark natural history,ecology,evolution and conservation. 展开更多
关键词 Phylogeny PHYLOGENOMICS Multispecies coalescent Lark PARAPHYLY Taxonomy Subfamily description
下载PDF
瞬态非傅里叶导热效应判据的探讨 被引量:13
2
作者 余宁 潘健生 +1 位作者 顾剑锋 胡明娟 《激光技术》 CAS CSCD 北大核心 2002年第2期156-158,143,共4页
讨论了通用傅里叶导热定律的数学模型 ,推导了半无限大物体在第一类边界条件下的基于非傅里叶导热定律的双曲线型偏微分方程的解析解。通过分析非傅里叶导热定律在瞬态条件下温度分布的变化过程 ,提出了非傅里叶导热效应的瞬态判据以及... 讨论了通用傅里叶导热定律的数学模型 ,推导了半无限大物体在第一类边界条件下的基于非傅里叶导热定律的双曲线型偏微分方程的解析解。通过分析非傅里叶导热定律在瞬态条件下温度分布的变化过程 ,提出了非傅里叶导热效应的瞬态判据以及非傅里叶导热的作用范围 ,对研究工程中瞬态导热问题 (如激光处理 ,电子束处理等 ) 展开更多
关键词 非傅里叶导热效应 瞬态判据 数学模型 瞬态导热
下载PDF
强瞬态非傅立叶导热效应判据与激光冲击硬化应用的探讨 被引量:4
3
作者 余宁 胡明娟 +1 位作者 潘健生 顾剑锋 《材料热处理学报》 EI CAS CSCD 北大核心 2001年第3期28-32,共5页
为了更好地反映激光冲击硬化的强瞬态特征及建立非傅立叶导热效应作用范围的判据 ,本文讨论了通用傅立叶导热定律的数学模型 ,推导了半无限大物体在第一类边界条件下基于非傅立叶导热定律的双曲线型偏微分方程的解析解。通过分析非傅立... 为了更好地反映激光冲击硬化的强瞬态特征及建立非傅立叶导热效应作用范围的判据 ,本文讨论了通用傅立叶导热定律的数学模型 ,推导了半无限大物体在第一类边界条件下基于非傅立叶导热定律的双曲线型偏微分方程的解析解。通过分析非傅立叶导热定律在瞬态条件下温度分布的变化过程 ,提出了非傅立叶导热效应的强瞬态判据。并就强瞬态导热现象对激光热处理的影响进行了讨论。指出按照非傅立叶导热定律计算能更好反映激光作用的热冲击特征。 展开更多
关键词 非傅立叶导热效应 强瞬态判据 激光冲击硬化
下载PDF
A Physical Layer Network Coding Based Tag Anti-Collision Algorithm for RFID System 被引量:3
4
作者 Cuixiang Wang Xing Shao +1 位作者 Yifan Meng Jun Gao 《Computers, Materials & Continua》 SCIE EI 2021年第1期931-945,共15页
In RFID(Radio Frequency IDentification)system,when multiple tags are in the operating range of one reader and send their information to the reader simultaneously,the signals of these tags are superimposed in the air,w... In RFID(Radio Frequency IDentification)system,when multiple tags are in the operating range of one reader and send their information to the reader simultaneously,the signals of these tags are superimposed in the air,which results in a collision and leads to the degrading of tags identifying efficiency.To improve the multiple tags’identifying efficiency due to collision,a physical layer network coding based binary search tree algorithm(PNBA)is proposed in this paper.PNBA pushes the conflicting signal information of multiple tags into a stack,which is discarded by the traditional anti-collision algorithm.In addition,physical layer network coding is exploited by PNBA to obtain unread tag information through the decoding operation of physical layer network coding using the conflicting information in the stack.Therefore,PNBA reduces the number of interactions between reader and tags,and improves the tags identification efficiency.Theoretical analysis and simulation results using MATLAB demonstrate that PNBA reduces the number of readings,and improve RFID identification efficiency.Especially,when the number of tags to be identified is 100,the average needed reading number of PNBA is 83%lower than the basic binary search tree algorithm,43%lower than reverse binary search tree algorithm,and its reading efficiency reaches 0.93. 展开更多
关键词 Radio frequency identification(RFID) tag anti-collision algorithm physical layer network coding binary search tree algorithm
下载PDF
Characterization on the Microstructures of Brominated Natural Rubber from Latex
5
作者 XUE Xinghua LIU Yafei +2 位作者 HAN Xiuping LI Guang WANG Zhiyong 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2019年第1期201-206,共6页
To elucidate the mechanism of brominated natural rubber(BNR), eight BNR samples with different bromine content were prepared from latex in different bromination time, and the microstructures were characterized by Four... To elucidate the mechanism of brominated natural rubber(BNR), eight BNR samples with different bromine content were prepared from latex in different bromination time, and the microstructures were characterized by Fourier transform infrared spectroscopy(FTIR) and ~1H-NMR spectroscopy, respectively. The hardness of BNR increased and its nature transformed from elastomer to resin with the increase of bromine content. Unlike chlorinated natural rubber(CNR), FTIR showed that there were no carbonyl groups on the molecular chains of BNR. ~1H-NMR spectroscopy revealed that the reaction activity of bromine and the secondary hydrogen atom of BNR were much higher than those of the primary one. The brominated substitution took place in the hydrogen atom of CH_3 and CH_2 groups firstly, then in the late period of bromination the bond of C=C was transferred to the saturated bond of C-C due to the Markovnikov addition of hydrogen bromide. Based on these findings, the mechanism of BNR from latex could be deduced as a free radical reaction and the detailed bromination process was presented. 展开更多
关键词 NATURAL RUBBER BROMINATION microstructure mechanism RADICAL reaction
下载PDF
Characterization of FeCo Nanoparticles Reinforced Natural Rubber using Nanomechanical Mapping
6
作者 XUE Xinghua WANG Zhiyong 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2018年第5期1223-1227,共5页
The morphology, nanomechanical properties and interfacial regions of natural rubber(NR) and FeCo nanoparticles composite were determined by AFM nanomechanical mapping. The results showed that the size of FeCo partic... The morphology, nanomechanical properties and interfacial regions of natural rubber(NR) and FeCo nanoparticles composite were determined by AFM nanomechanical mapping. The results showed that the size of FeCo particles was mostly from 40 to 100 nm and the FeCo nanoparticles were homogeneously dispersed in the NR bulk. The strength of NR composite increased with the FeCo nanoparticles loading. Young's modulus of NR region, FeCo region and interfacial region was measured by AFM nanomechanical tapping as 1.6 ± 0.6, 16.7 ±4.2 and 5.8 ± 1.5 MPa, respectively. The width of the interface for NR5, NR10 and NR15 was determined to be 15±8.1, 26±14.3 and 32±16.4 nm, respectively. 展开更多
关键词 FeCo nanoparticles natural rubber AFM nanomechanical mapping Young's modulus
下载PDF
Generational Gap: Intrinsic (Non-monetary) Versus Extrinsic (Monetary) Rewards in the Workforce
7
作者 Charles Chekwa Mmutakaego Chukwuanu Daisey Richardson 《Chinese Business Review》 2013年第6期414-424,共11页
Traditionally, organizations assume that compensation/pay and monetary benefits are what all employees need to work harder, be productive, or remain with the company. According to Abraham Maslow, within every person i... Traditionally, organizations assume that compensation/pay and monetary benefits are what all employees need to work harder, be productive, or remain with the company. According to Abraham Maslow, within every person is a hierarchy of five needs: physiological needs, safety needs, social needs, esteem needs, and self-actualization needs Organizations must be able to identify what employees desire to secure optimum performance and to meet the needs of both employees and employers. This research focuses on the generational gap and the significance of intrinsic and extrinsic rewards in the workforce. The purpose and objective of this research are to test the significance of monetary versus non-monetary rewards among the different generations in the organization. A self-designed questionnaire distributed to a multi-generational group of employees of selected organizations was used to collect the analyzed data. Sixty-five (65%) responses were obtained. Secondary data were used to elucidate the needs in this area of study. Because the workforce is predicted to become more diverse in terms of age, organizations will be unlikely to implement one set of rewards for the multiple generations. This is due to the differing expectations and requirements among the generations. However, the results indicate no significant difference in monetary versus non-monetary rewards among the different generations in the workforce. 展开更多
关键词 monetary benefits intrinsic reward extrinsic reward MOTIVATION multi-generational workforce monetary and non-monetary rewards
下载PDF
Development in a Time of War: South Sudan's Renewed Conflict and Its Toll Upon Development Prospects for the Region
8
作者 Justin Leach 《International Relations and Diplomacy》 2015年第8期547-554,共8页
This paper is an adaptation of a presentation given on March 20, 2015, at the Conference on International Development hosted by Virginia International University. The paper reviews the December 2013 outbreak of civil ... This paper is an adaptation of a presentation given on March 20, 2015, at the Conference on International Development hosted by Virginia International University. The paper reviews the December 2013 outbreak of civil war in South Sudan, and attempts to untangle the country's pre-existing development problems from those more directly related to the war. Finally, the paper discusses international involvement both in South Sudan's development and conflict resolution. It focuses in particular on the international debate over methods to end the conflict, the importance of state capacity, and the international understanding of development's relationship with the conflict. 展开更多
关键词 South Sudan civil war DEVELOPMENT China in Africa USA in Africa
下载PDF
Fault Detection and Test Response Compaction with Array of Two-Input Linear Logic
9
作者 Sunil R. Das Satyendra N. Biswas +2 位作者 Alexander R. Applegate Voicu Groza Mansour H. Assaf 《Journal of Electrical Engineering》 2014年第1期1-11,共11页
The design of space-efficient support hardware for built-in self-testing is of great significance in very large scale integration circuits and systems, particularly in view of the paradigm shift in recent times from s... The design of space-efficient support hardware for built-in self-testing is of great significance in very large scale integration circuits and systems, particularly in view of the paradigm shift in recent times from system-on-board to system-on-chip technology. The subject paper proposes a new approach to designing aliasing-free or zero-aliasing space compaction hardware targeting specifically embedded cores-based system-on-chips for single stuck-line faults extending well-known concept from conventional switching theory, viz. that of compatibility relation as used in the minimization of incomplete sequential machines. For a pair of response outputs of the circuit under test, the method introduces the notion of fault detection compatibility and conditional fault detection compatibility (conditional upon some other response output pair being simultaneously fault detection compatible) with respect to two-input XOR/XNOR logic. The process is illustrated with design details of space compressors for the International Symposium on Circuits and Systems or ISCAS 85 combinational and ISCAS 89 full-scan sequential benchmark circuits using simulation programs ATALANTA and FSIM, attesting to the usefulness of the technique for its relative simplicity, resultant low area overhead and full fault coverage for single stuck-line faults, thus making it suitable in commercial design environments. 展开更多
关键词 Aliasing-free space compaction built-in self-testing in very large scale integration circuits fault detection and conditionalfault detection compatibility system-on-chip.
下载PDF
A molecular-templating strategy to polyamine-incorporated porous organic polymers for unprecedented CO_2 capture and separation 被引量:4
10
作者 Dechuan Zhao Chunlong Kong +4 位作者 Hongbin Du Yonggang Yan Zhiyong U.Wang Hai-Long Jiang Liang Chen 《Science China Materials》 SCIE EI CSCD 2019年第3期448-454,共7页
Carbon capture and storage(CCS)is a feasible strategy to mitigate the increasing carbon dioxide(CO2)emission,which is believed to be responsible for ocean acidification and global warming.Simultaneously,the separation... Carbon capture and storage(CCS)is a feasible strategy to mitigate the increasing carbon dioxide(CO2)emission,which is believed to be responsible for ocean acidification and global warming.Simultaneously,the separation of CO2 from natural gas is also of critical importance in industry,because CO2 as the major impurity significantly reduces the conversion rate and energy content of natural gas[1].Currently,the main-stream technology for largescale capture and sorption of CO2 from industrial streams is amine-based wet scrubbing because the amine-based solutions have large CO2 capacity and high selectivity for acidic gases.However,a major drawback of their high heat capacity makes the regeneration very energy intensive and costly.To address the issue,solid porous adsorbents have emerged as the promising alternative owing to their much lower heat capacity. 展开更多
关键词 PEI PPN CCS
原文传递
“互联网+”背景下电商企业会计核算方法初探 被引量:3
11
作者 刘宇 《会计师》 2018年第10期65-66,共2页
目前,互联网技术在我国得到了全面的发展与应用,也给我国电商企业的发展带来了一定的影响,带动了我国传统企业会计核算方法的不断变革与创新。互联网技术的应用使传统的线下交易模式发展成为网络的线上交易形式,但由于我国的许多会计制... 目前,互联网技术在我国得到了全面的发展与应用,也给我国电商企业的发展带来了一定的影响,带动了我国传统企业会计核算方法的不断变革与创新。互联网技术的应用使传统的线下交易模式发展成为网络的线上交易形式,但由于我国的许多会计制度依然采用传统的模式,所以,网络电商会计核算与传统的会计核算之间存在一定的差异。本文主要阐述"互联网+"背景下电商企业会计核算的主要内容,通过分析"互联网+"背景下电商企业会计核算的影响与存在的主要问题,进而探究"互联网+"背景下电商企业会计核算的对策。这对提高企业的生产经营效率、增加会计核算的精准性具有重要的应用价值。 展开更多
关键词 “互联网+” 电商企业 会计核算方法
原文传递
网银的使用中的安全防护技术 被引量:1
12
作者 赵天勤 《网络安全技术与应用》 2014年第4期57-58,共2页
随着信息技术的高速发展,人们的生活节奏也越来越快,对快捷支付的需求越来越多,故而网络银行更多的受到百姓的关注。互联网的发展一方面满足人们的需求,但是另一方在安全问题上同样存在隐患。如何做好安全防护成为银行部门必须面对的问... 随着信息技术的高速发展,人们的生活节奏也越来越快,对快捷支付的需求越来越多,故而网络银行更多的受到百姓的关注。互联网的发展一方面满足人们的需求,但是另一方在安全问题上同样存在隐患。如何做好安全防护成为银行部门必须面对的问题,因为只有做好安全防护问题,才能让百姓的财产安全不受威胁。本文从多方面阐述银行在安全防护方面需要做的工作,以及其中存在的问题及解决办法,从而完善网银安全问题。 展开更多
关键词 网银 安全 防护技术 措施
原文传递
Area Query Processing Based on Gray Code in Wireless Sensor Networks
13
作者 Chunyu Ai Yueming Duan +1 位作者 Mingyuan Yan Jing He 《Tsinghua Science and Technology》 SCIE EI CAS 2012年第5期499-511,共13页
Area query processing is significant for various applications of wireless sensor networks since it can request information of particular areas in the monitored environment. Existing query processing techniques cannot ... Area query processing is significant for various applications of wireless sensor networks since it can request information of particular areas in the monitored environment. Existing query processing techniques cannot solve area queries. Intuitively, centralized processing on Base Station can accomplish area queries via collecting information from all sensor nodes. However, this method is not suitable for wireless sensor networks with limited energy since a large amount of energy is wasted for reporting useless data. This motivates us to propose an energy-efficient in-network area query processing scheme. In our scheme, the monitored area is partitioned into grids, and a unique gray code number is used to represent a Grid ID (GID), which is also an effective way to describe an area. Furthermore, a reporting tree is constructed to process area merging and data aggregations. Based on the properties of GIDs, subareas can be merged easily and useless data can be discarded as early as possible to reduce energy consumption. For energy-efficiently answering continuous queries, we also design an incremental update method to continuously generate query results. In essence, all of these strategies are pivots to conserve energy consumption. With a thorough simulation study, it is shown that our scheme is effective and energy-efficient 展开更多
关键词 area query area query processing gray code wireless sensor networks
原文传递
翻译及语言学习:这是个大问题(英文)
14
作者 冯睿 徐弘 《亚太跨学科翻译研究》 2015年第1期170-179,共10页
一般来说,笔译或口译被看作是在母语之外另学任何一门语言的结果,也可看作是至少掌握两门语言后的应用。不过,笔译与口译会带来两种副产品。一个是笔译及口译势必包含重复学习,从而造成语言学习的效率不足百分之五十。另一个就是笔译及... 一般来说,笔译或口译被看作是在母语之外另学任何一门语言的结果,也可看作是至少掌握两门语言后的应用。不过,笔译与口译会带来两种副产品。一个是笔译及口译势必包含重复学习,从而造成语言学习的效率不足百分之五十。另一个就是笔译及口译中产生的(中)介语是一种语言错误,綦难消除。通过分析这两种副产品的起因,本文试图说明笔译及口译对多语使用者在交流与语言学习中起到的作用。 展开更多
关键词 笔译 口译 重复学习 (中)介语 效率
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部