Systematics of the avian family Alaudidae using multilocus and genomic data

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.

瞬态非傅里叶导热效应判据的探讨

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 )

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

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。

A Physical Layer Network Coding Based Tag Anti-Collision Algorithm for RFID System

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.

Characterization on the Microstructures of Brominated Natural Rubber from Latex

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.

Characterization of FeCo Nanoparticles Reinforced Natural Rubber using Nanomechanical Mapping

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.

分子模板法策略制备多胺注入的多孔有机聚合物实现高效CO_2捕获与分离（英文）

本论文用简单、通用的分子模板策略制备了具有极高CO_2吸附与分离效率的多胺注入多孔有机聚合物(POPs).在该策略中, CO_2分子存在下,多胺能均匀分散在母体多孔材料中. CO_2模板分子能够产生有效的均匀分布孔,能允许CO_2分子进入但不允许其他较大分子如N_2和CH_4进入.在0.15 bar和323 K下,制备的PPN-6/PEI-165展现出超高的4.52 mmol g^(-1)CO_2吸附量且没有检测到N_2和CH_4吸附.此外,该材料对水汽稳定且温和条件(343K下真空)下易再生.据我们所知,该结果在迄今为止所报道的固体多孔吸附剂中有最好的CO_2选择性捕获性能.

“互联网+”背景下电商企业会计核算方法初探

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。

网银的使用中的安全防护技术

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。

Area Query Processing Based on Gray Code in Wireless Sensor Networks

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

翻译及语言学习:这是个大问题(英文)

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。