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爱默生nature第一章译文

爱默生的《自然》一书是一部非常经典的哲学作品，其深度和广度都能引起人们的深思和反思。

在本文中，我将根据你提供的要求和主题，以深度和广度的方式来评估和探讨爱默生的《自然》第一章，并撰写一篇有价值的文章。

《自然》第一章是爱默生的经典之作，其主要讨论了关于自然的主题，探讨了自然对于人类的影响和意义。

在这一章中，爱默生提出了许多关于自然的观点和理念，展现了他对自然的理解和热爱。

他认为，自然是我们周围最重要的资源，它是我们心灵的营养，也是我们灵魂的滋养。

我们应当尊重自然，与自然和谐相处。

我们可以从爱默生对自然的定义开始。

在《自然》第一章中，爱默生将自然定义为“创造力的行为”。

他认为，自然是指神秘的造物者所创造的一切，包括天空、大地、山川、河流、动植物等等。

他将自然视作巨大的有机体，每一样事物都是相互联系和互相影响的。

这种对自然的定义，展现了爱默生对于自然的宏大和严谨的理解。

我们可以探讨爱默生对于自然与人的关系的见解。

在《自然》第一章中，爱默生提出了自然对于人类的影响和教导。

他认为，自然是人类的良师，她默默地教导我们如何与自然相处、如何与自然和谐相处、以及如何对待自然。

我们应当尊敬自然，学习自然，与自然和谐共生。

爱默生还展现了对于自然美的独特见解。

在《自然》第一章中，他对于自然美的解读深入浅出，从每一样微小的事物中发现了美。

他认为，自然之美不仅仅存在于壮丽的大自然中，更存在于日常生活的细微之处。

这种对于自然美的理解，启发了我们重新审视并欣赏身边的一草一木。

在总结回顾性内容方面，我们可以看到，《自然》第一章内容丰富，涉及面广。

爱默生以简洁的语言展现了对自然的敬畏和热爱，他以自己独特的视角来解读自然，启发了无数读者对自然的理解和感悟。

我想共享一下我个人对于《自然》第一章的理解和观点。

在我看来，爱默生以他独特的视角和深刻的思考，对自然进行了深入的解读和探讨，展现了他对自然的敬畏和热爱。

他对于自然美的理解也给了我很深的启发，让我重新审视和欣赏身边的一切美好事物。

爱默生nature第一章译文

爱默生nature第一章译文
（原创版）
目录
1.爱默生的《论自然》第一章概述
2.第一章的主要内容：自然的神圣与静止不变的崇高境界
3.爱默生对自然的认识：自然只是智慧的影子或模仿物，是灵魂中次要的东西
4.爱默生对离群索居的看法：一个人要想离群索居，就需要像远离社会那样，远远地避开他的卧室
5.爱默生对独处的看法：当你在独处时，可以去看天上的星星，从天国传来的光线会将你和你触摸的东西分离开来
6.爱默生对静止不变的崇高境界的认识：在凝视那美妙的星体时，人们可以领悟到静止不变的崇高境界
7.爱默生的哲学思想：我们应该有自己的诗篇，有自己体会到的哲学，而不仅仅是历史上留下的
正文
爱默生的《论自然》第一章主要阐述了自然的神圣与静止不变的崇高境界。

他认为，自然只是智慧的影子或模仿物，是灵魂中次要的东西。

在他看来，一个人要想离群索居，就需要像远离社会那样，远远地避开他的卧室。

爱默生提倡在独处时，可以去看天上的星星，从天国传来的光线会将你和你触摸的东西分离开来。

在凝视那美妙的星体时，人们可以领悟到静止不变的崇高境界。

这种境界使人们在纷繁复杂的世界中找到了片刻的宁静与安宁，体会到了自然的神圣与伟大。

此外，爱默生强调我们应该有自己的诗篇，有自己体会到的哲学，而
不仅仅是历史上留下的。

他的哲学思想鼓励人们去探索自己与宇宙之间本来的关系，去发现和创造属于自己的诗篇和哲学。

总之，在《论自然》第一章中，爱默生以自然为切入点，探讨了人与自然的关系，强调了独处和静止不变的崇高境界的重要性，并倡导人们去发掘和创造属于自己的诗歌和哲学。

拉尔夫沃尔多艾默生nature文章的译文to get to

拉尔夫沃尔多艾默生nature文章的译文to get toMine are the night and morning，我拥有黑夜与清晨，The pits of air， the gulf of space，大气的沟壑，空间的深渊，The sportive sun， the gibbous moon，太阳嬉闹，月华盈盈，The innumerable days.数不清的一天天。

I hid in the solar glory，我躲进阳光的辉煌，I am dumb in the pealing song，在隆隆的歌里沉默，I rest on the pitch of the torrent，停在洪流的波面，In slumber I am strong.我在酣眠中强壮。

No numbers have counted my tallies，没有数字将我计数，No tribes my house can fill，没有部落充满我的房屋，I sit by the shining Fount of Life，坐在波光潋滟的生命泉边，And pour the deluge still；我默默将洪流倾注；And ever by delicate powers曾经倚靠精妙的力Gathering along the centuries沿着诸多的世纪采集From race on race the rarest flowers，一种接一种珍稀的花朵，My wreath shall nothing miss.我的花冠上什么都不会逃过。

And many a thousand summers经过成千上万个夏季My apples ripened well，我的苹果都成熟得健康，And light from meliorating stars 变化着的星星闪烁With firmer glory fell.撒下坚实的光芒。

I wrote the past in characters 我用岩石的质地书写往昔Of rock and fire the scroll.并焚烧那些纸制卷轴。

nature审稿邮件原文

nature审稿邮件原文Nature审稿邮件原文尊敬的作者：感谢您选择将您的研究成果提交给我们的期刊。

我们已经完成了对您提交的论文进行的审稿工作，并针对您的研究提供了一些建议和意见。

在这封邮件中，我们将详细介绍审稿结果，并希望这些意见对您进一步完善您的研究工作有所帮助。

让我们对您的研究表示赞赏。

您的研究题目《自然界的美与奇观》非常吸引人，并且在方法和数据采集方面有着一定的创新。

您的研究结果表明，自然界中存在着丰富多样的美丽景观和令人惊叹的奇观，这对我们深入了解和保护自然资源具有重要意义。

在审稿过程中，我们的审稿人提出了一些对您的研究进一步改进的建议。

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您可以进一步解释您采用的数据收集方法、样本选择标准以及数据处理的具体步骤。

这样可以使读者更好地理解您的研究过程，并验证您的研究结论的可靠性。

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他们建议您对研究结果进行更深入的分析和解释，以进一步探讨美与奇观背后的原因和机制。

您可以参考相关文献，加入对比分析和理论解释，从而提升论文的学术价值。

审稿人还对您的论文的结构和语言进行了一些修改建议。

他们建议您在文章中使用恰当的段落和标题，使文章结构清晰，易于阅读。

同时，他们还指出了一些语法和拼写错误，建议您仔细检查并进行修正。

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我们希望您能认真考虑这些意见，并对您的研究进行进一步的修订和完善。

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[2009][Nature][N...

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It is also crucial for developing sustainable industrial processes for manufacturing fuels. In large-scale chemi-cal processes, such ‘bond control’ is typically exerted by the surfaces of catalysts that consist of porous solids, or of nanoparticles supported on other materials. Writing in Angewandte Chemie, Loffreda et al.1 report an essential step towards understanding the order in which chemical bonds form in molecules bound to a catalyst’s surface. They consider a prototype reaction in which unsaturated aldehydes react with hydrogen on a platinum surface (Fig. 1), and show that quantum chemical calculations can provide a simple set of rules to determine which bond is hydrogenated first. Quantum chemical methods for describing surface reactions have developed extensively during the past decade, and have now reached the point at which complete catalytic reac-tions can be described in some detail. Indeed, the first examples in which such insight has been used to design new catalysts have been reported2–5. Currently, however, only the sim-plest reactions can be modelled in full using quantum calculations. For complex reaction networks, a more promising approach is to develop an understanding of which factors within a network determine the overall rates. For questions relating to reaction selectivity — that is, which bond reacts first — the challenge is to identify the descriptors that determine the relative rates of all of the possible pathways in which different bonds react. These descrip-tors can then be calculated or measured in the search for new catalysts.The overall reactivity of a given catalyst is traditionally understood in terms of the Sabatier principle6, which states that the rate of a reaction is maximized when the inter a ctions between the intermediates and the catalyst are neither too weak nor too strong. Weakbonding makes the catalyst too inert to allowthe reaction to take place, whereas over l ystrong bonding may cause the catalyst to holdon to intermediates, hampering the formationof products. The energies of bonds formedbetween the main reaction intermediates andcatalytic surfaces therefore determine the overallcatalytic rate, and can be used as descriptorsof that rate2. Only a few bond energies areusually needed to determine a catalyst’s reacti-vity, because the various parameters associatedwith reactivity tend to scale with each other,effectively limiting the number of independentvariables2,7. Specifically, the activation energiesof reactions (the energies required to initiatereactions) generally scale with the energydifference between reaction inter m ediates,and surface-bond energies for different inter-mediates in a reaction pathway often scale witheach other.Loffreda et al.1 report that specific surface-bond energies also work as descriptors for reac-tion selectivity. They first show that the orderin which the different double bonds of acrolein(a simple unsaturated aldehyde, C3H4O) arehydrogenated on the surface of a metal suchas platinum can be understood by dividing allof the possible reactions that could occur intofour groups. Each group is defined by its reac-tion centre — one of the three carbon atoms,or the oxygen atom. The authors find that,for each group and at any given point along areaction pathway, the transition-state energy(the energy at which the complex of reactantsbecomes more product-like than reactant-like)scales linearly with the surface-bond energy ofthe preceding intermediate–metal complex. Infact, there is an almost one-to-one correlationbetween the energies. This means that the acti-vation energies for all of the different reactionsthat can take place at each centre are about thesame, something that has also been found instudies of smaller molecules reacting on avariety of transition metals8.Intriguingly, Loffreda et al.1 go on to showthat the same scaling relationship also appliesto another unsaturated aldehyde, prenal. Thismeans that the transition-state energies for pre-nal hydrogenation could have been predictedby calculating the surface-bond energies forthe relevant reaction centres of that molecule.For any given reaction that has several possiblereaction pathways, the one that has the lowesttransition-state energy typically has the fast-est rate — it will occur before the others. Theauthors have therefore shown that surface-bond energy is a descriptor of reaction selec-tivity. If this is a general result, then it will allowthe reaction selectivities for hydrogenations ofmany aldehydes on many different catalysts tobe screened rapidly using quantum chemicalcalculations. Hydrogenations are exception-ally useful reactions in industry, so this is anexciting prospect.Loffreda and colleagues’ work exemplifiesthe great progress that has been made in ourunderstanding of solid-state catalysts in recentyears as a direct result of quantum chemical cal-culations. Extending the use of computationaltechniques to complex reaction networks is thenext great challenge — but there are already Figure 1 | Selective hydrogenation of theunsaturated aldehyde acrolein. Acrolein can, inprinciple, react with hydrogen in the presence ofa metal catalyst to yield four possible products:propanal, a saturated aldehyde; propenol, anunsaturated alcohol; (E)-1-propenol, an enol;and the fully hydrogenated compound propanol,a saturated alcohol. Loffreda et al.1 find that therates of each reaction are governed entirely by thestrength with which the respective intermediatesbind to the surface of the catalyst. This parametercan thus be used to predict which bonds ofunsaturated aldehydes will react in catalytichydrogenations. Carbon atoms, grey; oxygenatoms, red; hydrogen atoms, white.CatalystAcroleinPropanalPropenolPropanol(E)-1-Propenol686, L57–L60 (2008).10. Greiner, J. et al.Astrophys. J.693, 1610–1620 (2009).11. Bromm, V. & Loeb, A. Astrophys. J.642, 382–388 (2006).12. Chandra, P. et al. Preprint at /abs/0910.4367 (2009).13. Zhang, B. et al.Astrophys. J.703, 1696–1724 (2009).14. Gehrels, N., Ramirez-Ruiz, E. & Fox, D. B. Annu. Rev. Astron.Astrophys.47, 567–617 (2009).15. Bennett, J. et al.Essential Cosmic Perspective 3rd edn, 432(Pearson Education, 2005).promising signs that this can be done, and that these techniques will become an essential tool for catalyst design. To fulfil this promise, improvements to the accuracy of quantum chemical calculations are needed, as well as faster computers and algorithms to enable calculations for systems of greater complexity. But perhaps more critically, as Loffreda et al.1 show, we need the insight provided by compu-tational techniques to distinguish between the important and the less important parameters of catalysis. ■Jens K. Nørskov and Frank Abild-Pedersen are in the Department of Physics, Center for Atomic-scale Materials Design, T echnical University of Denmark, 2800 Kongens Lyngby, Denmark.e-mails:*****************.dk;***************.dk1. Loffreda, D., Delbecq, F., Vigné, F. & Sautet, P. Angew. Chem.Int. Edn doi: 10.1002/anie.200902800 (2009).2. Nørskov, J. K., Bligaard, T., Rossmeisl, J. & Christensen, C. H.Nature Chem.1, 37–46 (2009).3. Linic, S., Jankowiak, J. & Barteau, M. A. J. Catal.224,489–493 (2004).4. T oulhoat, H. & Raybaud, P. J. Catal.216, 63–72 (2003).5. Greeley, J. & Mavrikakis, M. 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How a protein finds the correct spot to bind to among all the possi-ble sites (3 billion base pairs in the human genome, for example) has been the preoccu-pation of molecular and structural biologists for decades.Watson and Crick taught us that DNA adopts the form of a double helix, and much of DNA’s biological function is evident from the com-plementary strands that make up this iconic helix. These days, we tend to think of DNA as a string of letters (A, G, C and T), which stand for the bases of the four nucleotides that make up the DNA polymer. The familiar genetic code consists of sets of three DNA nucleotides that specify one of the 20 amino acids that make up proteins; the deciphering of this code was one of the triumphs of the early days of molecular biology.One might imagine that a protein could recognize its binding site in the genome by somehow ‘reading’ these letters, and in fact this has been found to be the case from study-ing structures of protein–DNA complexes. The DNA double helix has two grooves, a major and a minor one, that wind around the central axis of the molecule, and reading is achieved using hydrogen bonds that form between protein side chains and the edges of the DNA nucleo-tides that are exposed in the major groove. But unlike the genetic code, a simple code for protein recognition of DNA has not emerged despite years of effort.Perhaps we lose something in the simpli-fication of DNA to a one-dimensional string of letters. We may forget that DNA is a mol-ecule with a three-dimensional shape that isnot perfectly uniform. Rohs et al.1 (page 1248of this issue) now find that one structuralfeature of DNA, the shape of its minor groove,can be exploited by proteins for specificrecognition.A particular sequence of nucleotide letterspresents a unique array of hydrogen-bonddonors and acceptors in the major groove,providing a clear mechanism for reading thatsequence2. The minor groove, though, has beeninscrutable, as a simple code of hydrogen-bonddonors and acceptors that specify a nucleotidesequence is not present in this groove.The minor groove has another trick up itssleeve— its width varies depending on whichnucleotides are present in a segment of DNA.And the width of the minor groove has a physi-cal consequence that goes beyond the merelystructural, stemming from the charged groups(phosphates) that are arrayed along the outeredge of the DNA backbone, one per nucleotide(Fig. 1a). Where the minor groove is narrow, theelectric-field lines due to the negatively chargedphosphates are focused into the groove, leadingto an enhanced negative electrostatic potentialin that segment of the double helix.Rohs and colleagues1 exhaustively searchedthe databases of three-dimensional structuresof protein–DNA complexes and found manyexamples of proteins that use amino acidscontaining positively charged side chains,principally arginines, to read the electrostaticpotential of the minor groove. Where the groovewidth and electrostatic potential are optimal,an arginine side chain of a DNA-binding pro-tein is often seen to sit snugly in the minorgroove (Fig. 1b). It is important to appreciatethat this mechanism of DNA recognition isdistinct from the direct readout of hydrogen-bond donors and acceptors in the majorgroove, because different strings of nucleotidescan adopt similar minor-groove shapes.For this to be a means of recognizing infor-mation encoded in the DNA sequence, theremust be particular nucleotide sequences thatresult in a narrow minor groove. Again, bysearching the structural databases, Rohs et al.1found that short runs of adenine nucleotides(called A-tracts) have a strong tendency toinduce a narrow minor groove. The specialstructural properties of A-tracts have beenknown for three decades, and have been princi-pally associated with DNA-sequence-directedcurvature3. Curvature of DNA requires a seriesof short A-tracts, spaced at the DNA helixrepeat of 10 base pairs. What is new in Rohs andcolleagues’ analysis1 is their demonstration thatan isolated A-tract can influence DNA shape insuch a way that it can serve as a site for specificrecognition by DNA-binding proteins.abMajor grooveDNA-bindingproteinMinor grooveFigure 1 | Getting into the groove. Rohs et al.1report that the shape of the minor groove ofDNA can direct the binding of proteins tospecific sites. a, Negatively charged phosphategroups (magenta) are arrayed along the outeredge of the DNA major and minor grooves thatspiral around the axis of the double helix. Thewidth of the minor groove varies dependingon the sequence of nucleotides. This variationleads to differences in the distance betweenphosphates across the groove, which in turn leadto variation in the negative electrostatic potentialalong the minor groove. b, A representationof a DNA-binding protein (green) that has apositively charged side chain on its surface,for example arginine (purple), is shown. Theprotein may recognize a binding site on DNAby its electrostatic potential. The protein isabout to bind to the segment of the DNA minorgroove that has the optimum groove widthand electrostatic potential for binding (red).The DNA structure in a and b is derived froma structure in the RCSB Protein Data Bank,accession number 2O61. The illustration of aDNA-binding protein in b is hypothetical.。

爱默生NATURE英文

N A T U R EThe rounded world is fair to see,Nine times folded in mystery:Though baffled seers cannot impartThe secret of its laboring heart,Throb thine with Nature's throbbing breast,And all is clear from east to west.Spirit that lurks each form withinBeckons to spirit of its kin;Self-kindled every atom glows,And hints the future which it owes.Essay VI _Nature_There are days which occur in this climate, at almost any season of the year, wherein the world reaches its perfection, when the air, the heavenly bodies, and the earth, make a harmony, as if nature would indulge her offspring; when, in these bleak upper sides of the planet, nothing is to desire that we have heard of the happiest latitudes, and we bask in the shining hours of Florida and Cuba; when everything that has life gives sign of satisfaction, and the cattle that lie on the ground seem to have great and tranquil thoughts. These halcyons may be looked for with a little more assurance in that pure October weather, which we distinguish by the name of the Indian Summer. The day, immeasurably long, sleeps over the broad hills and warm wide fields. To have lived through all its sunny hours, seems longevity enough. The solitary places do not seem quite lonely. At the gates of the forest, the surprised man of the world is forced to leave his city estimates of great and small, wise and foolish. The knapsack of custom falls off his back with the first step he makes into these precincts. Here is sanctity which shames our religions, and reality which discredits our heroes. Here we find nature to be the circumstance which dwarfs every other circumstance, and judges like a god all men that come to her. We have crept out of our close and crowded houses into the night and morning, and we see what majestic beauties daily wrap us in their bosom. How willingly we would escape the barriers which render them comparatively impotent, escape the sophistication and second thought, and suffer nature to intrance us. The tempered light of the woods is like a perpetual morning, and is stimulating and heroic. The anciently reported spells of these places creep on us. The stems of pines, hemlocks, and oaks, almost gleam like iron on the excited eye. The incommunicable trees begin to persuade us to live with them, and quit our life of solemn trifles. Here no history, or church, or state, is interpolated on the divine sky and the immortal year. How easily we might walk onward into the opening landscape, absorbed by new pictures, and by thoughts fast succeeding each other, until by degrees the recollection of home was crowded out of the mind, all memory obliterated by the tyranny of the present, and we were led in triumph by nature.These enchantments are medicinal, they sober and heal us. These are plain pleasures, kindly and native to us. We come to our own, and make friends with matter, which the ambitious chatter of the schools would persuade us to despise. We never can part with it; the mind loves its old home: as water to our thirst, so is the rock, the ground, to our eyes, and hands, and feet. It is firm water: it is cold flame: what health, what affinity! Ever an old friend, ever like a dear friend and brother, when we chat affectedly with strangers, comes in this honest face, and takes a grave liberty with us, and shames us out of our nonsense. Cities give not the human senses room enough. We go out daily and nightly to feed the eyes on the horizon, and require so much scope, just as we need water for our bath. There are all degrees of natural influence, from these quarantine powers of nature, up to her dearest and gravest ministrations to the imagination and the soul. There is the bucket of cold water from the spring, the wood-fire to which the chilled traveller rushes for safety, -- and there is the sublime moral of autumn and of noon. We nestle in nature, and draw our living as parasites from her roots and grains, and we receive glances from the heavenly bodies, which call us to solitude, and foretell the remotest future. The blue zenith is the point in which romance and reality meet. I think, if we should be rapt away into all that we dream of heaven, and should converse with Gabriel and Uriel, the upper sky would be all that would remain of our furniture.It seems as if the day was not wholly profane, in which we have given heed to some natural object. The fall of snowflakes in a still air, preserving to each crystal its perfect form; the blowing of sleet over a wide sheet of water, and over plains, the waving rye-field, the mimic waving of acres of houstonia, whose innumerable florets whiten and ripple before the eye; the reflections of trees and flowers in glassy lakes; the musical steaming odorous south wind, which converts all trees to windharps; the crackling and spurting of hemlock in the flames; or of pine logs, which yield glory to the walls and faces in the sittingroom, -- these are the music and pictures of the most ancient religion. My house stands in low land, with limited outlook, and on the skirt of the village. But I go with my friend to the shore of our little river, and with one stroke of the paddle, I leave the village politics and personalities, yes, and the world of villages and personalities behind, and pass into a delicate realm of sunset and moonlight, too bright almost for spotted man to enter without noviciate and probation. We penetrate bodily this incredible beauty; we dip our hands in this painted element: our eyes are bathed in these lights and forms. A holiday, a villeggiatura, a royal revel, the proudest, most heart-rejoicing festival that valor and beauty, power and taste, ever decked and enjoyed, establishes itself on the instant. These sunset clouds, these delicately emerging stars, with their private and ineffable glances, signify it and proffer it. I am taught the poorness of our invention, the ugliness of towns and palaces. Art and luxury have early learned that they must work as enhancement and sequel to this original beauty. I am over-instructed for my return. Henceforth I shall be hard to please. I cannot go back to toys. I am grown expensive and sophisticated. I can no longer live without elegance: but a countryman shall be my master of revels. He who knows the most, he who knows what sweets and virtues are in the ground, the waters, the plants, the heavens, and how to come at these enchantments, is the rich and royal man. Only as far as the masters of the world havecalled in nature to their aid, can they reach the height of magnificence. This is the meaning of their hanging-gardens, villas, garden-houses, islands, parks, and preserves, to back their faulty personality with these strong accessories. I do not wonder that the landed interest should be invincible in the state with these dangerous auxiliaries. These bribe and invite; not kings, not palaces, not men, not women, but these tender and poetic stars, eloquent of secret promises. We heard what the rich man said, we knew of his villa, his grove, his wine, and his company, but the provocation and point of the invitation came out of these beguiling stars. In their soft glances, I see what men strove to realize in some Versailles, or Paphos, or Ctesiphon. Indeed, it is the magical lights of the horizon, and the blue sky for the background, which save all our works of art, which were otherwise bawbles. When the rich tax the poor with servility and obsequiousness, they should consider the effect of men reputed to be the possessors of nature, on imaginative minds. Ah! if the rich were rich as the poor fancy riches! A boy hears a military band play on the field at night, and he has kings and queens, and famous chivalry palpably before him. He hears the echoes of a horn in a hill country, in the Notch Mountains, for example, which converts the mountains into an Aeolian harp, and this supernatural tiralira restores to him the Dorian mythology, Apollo, Diana, and all divine hunters and huntresses. Can a musical note be so lofty, so haughtily beautiful! To the poor young poet, thus fabulous is his picture of society; he is loyal; he respects the rich; they are rich for the sake of his imagination; how poor his fancy would be, if they were not rich! That they have some high-fenced grove, which they call a park; that they live in larger and better-garnished saloons than he has visited, and go in coaches, keeping only the society of the elegant, to watering-places, and to distant cities, are the groundwork from which he has delineated estates of romance, compared with which their actual possessions are shanties and paddocks. The muse herself betrays her son, and enhances the gifts of wealth and well-born beauty, by a radiation out of the air, and clouds, and forests that skirt the road, -- a certain haughty favor, as if from patrician genii to patricians, a kind of aristocracy in nature, a prince of the power of the air.The moral sensibility which makes Edens and Tempes so easily, may not be always found, but the material landscape is never far off. We can find these enchantments without visiting the Como Lake, or the Madeira Islands. We exaggerate the praises of local scenery. In every landscape, the point of astonishment is the meeting of the sky and the earth, and that is seen from the first hillock as well as from the top of the Alleghanies. The stars at night stoop down over the brownest, homeliest common, with all the spiritual magnificence which they shed on the Campagna, or on the marble deserts of Egypt. The uprolled clouds and the colors of morning and evening, will transfigure maples and alders. The difference between landscape and landscape is small, but there is great difference in the beholders. There is nothing so wonderful in any particular landscape, as the necessity of being beautiful under which every landscape lies. Nature cannot be surprised in undress. Beauty breaks in everywhere.But it is very easy to outrun the sympathy of readers on this topic, which schoolmen called _natura naturata_, or nature passive. One can hardly speak directly of it withoutexcess. It is as easy to broach in mixed companies what is called "the subject of religion."A susceptible person does not like to indulge his tastes in this kind, without the apology of some trivial necessity: he goes to see a wood-lot, or to look at the crops, or to fetch a plant or a mineral from a remote locality, or he carries a fowling piece, or a fishing-rod.I suppose this shame must have a good reason. A dilettantism in nature is barren and unworthy. The fop of fields is no better than his brother of Broadway. Men are naturally hunters and inquisitive of wood-craft, and I suppose that such a gazetteer as wood-cutters and Indians should furnish facts for, would take place in the most sumptuous drawingrooms of all the "Wreaths" and "Flora's chaplets" of the bookshops; yet ordinarily, whether we are too clumsy for so subtle a topic, or from whatever cause, as soon as men begin to write on nature, they fall into euphuism. Frivolity is a most unfit tribute to Pan, who ought to be represented in the mythology as the most continent of gods. I would not be frivolous before the admirable reserve and prudence of time, yet I cannot renounce the right of returning often to this old topic. The multitude of false churches accredits the true religion. Literature, poetry, science, are the homage of man to this unfathomed secret, concerning which no sane man can affect an indifference or incuriosity. Nature is loved by what is best in us. It is loved as the city of God, although, or rather because there is no citizen. The sunset is unlike anything that is underneath it: it wants men. And the beauty of nature must always seem unreal and mocking, until the landscape has human figures, that are as good as itself. If there were good men, there would never be this rapture in nature. If the king is in the palace, nobody looks at the walls. It is when he is gone, and the house is filled with grooms and gazers, that we turn from the people, to find relief in the majestic men that are suggested by the pictures and the architecture. The critics who complain of the sickly separation of the beauty of nature from the thing to be done, must consider that our hunting of the picturesque is inseparable from our protest against false society. Man is fallen; nature is erect, and serves as a differential thermometer, detecting the presence or absence of the divine sentiment in man. By fault of our dulness and selfishness, we are looking up to nature, but when we are convalescent, nature will look up to us. We see the foaming brook with compunction: if our own life flowed with the right energy, we should shame the brook. The stream of zeal sparkles with real fire, and not with reflex rays of sun and moon. Nature may be as selfishly studied as trade. Astronomy to the selfish becomes astrology; psychology, mesmerism (with intent to show where our spoons are gone); and anatomy and physiology, become phrenology and palmistry.But taking timely warning, and leaving many things unsaid on this topic, let us not longer omit our homage to the Efficient Nature, _natura naturans_, the quick cause, before which all forms flee as the driven snows, itself secret, its works driven before it in flocks and multitudes, (as the ancient represented nature by Proteus, a shepherd,) and in undescribable variety. It publishes itself in creatures, reaching from particles and spicula, through transformation on transformation to the highest symmetries, arriving at consummate results without a shock or a leap. A little heat, that is, a little motion, is all that differences the bald, dazzling white, and deadly cold poles of the earth from the prolific tropical climates. All changes pass without violence, by reason of the twocardinal conditions of boundless space and boundless time. Geology has initiated us into the secularity of nature, and taught us to disuse our dame-school measures, and exchange our Mosaic and Ptolemaic schemes for her large style. We knew nothing rightly, forwant of perspective. Now we learn what patient periods must round themselves before the rock is formed, then before the rock is broken, and the first lichen race has disintegrated the thinnest external plate into soil, and opened the door for the remote Flora, Fauna, Ceres, and Pomona, to come in. How far off yet is the trilobite! How far the quadruped! how inconceivably remote is man! All duly arrive, and then race after race of men. It is a long way from granite to the oyster; farther yet to Plato, and the preaching of the immortality of the soul. Yet all must come, as surely as the first atom has two sides.Motion or change, and identity or rest, are the first and second secrets of nature: Motion and Rest. The whole code of her laws may be written on the thumbnail, or the signet of a ring. The whirling bubble on the surface of a brook, admits us to the secret of the mechanics of the sky. Every shell on the beach is a key to it. A little water made to rotate in a cup explains the formation of the simpler shells; the addition of matter from year to year, arrives at last at the most complex forms; and yet so poor is nature with all her craft, that, from the beginning to the end of the universe, she has but one stuff, -- but one stuff with its two ends, to serve up all her dream-like variety. Compound it how she will, star, sand, fire, water, tree, man, it is still one stuff, and betrays the same properties.Nature is always consistent, though she feigns to contravene her own laws. She keeps her laws, and seems to transcend them. She arms and equips an animal to find its place and living in the earth, and, at the same time, she arms and equips another animal to destroy it. Space exists to divide creatures; but by clothing the sides of a bird with a few feathers, she gives him a petty omnipresence. The direction is forever onward, but the artist still goes back for materials, and begins again with the first elements on the most advanced stage: otherwise, all goes to ruin. If we look at her work, we seem to catch a glance of a system in transition. Plants are the young of the world, vessels of health and vigor; but they grope ever upward towards consciousness; the trees are imperfect men, and seem to bemoan their imprisonment, rooted in the ground. The animal is the novice and probationer of a more advanced order. The men, though young, having tasted the first drop from the cup of thought, are already dissipated: the maples and ferns are still uncorrupt; yet no doubt, when they come to consciousness, they too will curse and swear. Flowers so strictly belong to youth, that we adult men soon come to feel, that their beautiful generations concern not us: we have had our day; now let the children have theirs. The flowers jilt us, and we are old bachelors with our ridiculous tenderness.Things are so strictly related, that according to the skill of the eye, from any one object the parts and properties of any other may be predicted. If we had eyes to see it, a bit of stone from the city wall would certify us of the necessity that man must exist, as readily as the city. That identity makes us all one, and reduces to nothing great intervals on our customary scale. We talk of deviations from natural life, as if artificial life were not also natural. The smoothest curled courtier in the boudoirs of a palace has an animalnature, rude and aboriginal as a white bear, omnipotent to its own ends, and is directly related, there amid essences and billetsdoux, to Himmaleh mountain-chains, and the axis of the globe. If we consider how much we are nature's, we need not be superstitious about towns, as if that terrific or benefic force did not find us there also, and fashion cities. Nature who made the mason, made the house. We may easily hear too much of rural influences. The cool disengaged air of natural objects, makes them enviable to us, chafed and irritable creatures with red faces, and we think we shall be as grand as they, if we camp out and eat roots; but let us be men instead of woodchucks, and the oak and the elm shall gladly serve us, though we sit in chairs of ivory on carpets of silk.This guiding identity runs through all the surprises and contrasts of the piece, and characterizes every law. Man carries the world in his head, the whole astronomy and chemistry suspended in a thought. Because the history of nature is charactered in his brain, therefore is he the prophet and discoverer of her secrets. Every known fact in natural science was divined by the presentiment of somebody, before it was actually verified. A man does not tie his shoe without recognising laws which bind the farthest regions of nature: moon, plant, gas, crystal, are concrete geometry and numbers. Common sense knows its own, and recognises the fact at first sight in chemical experiment. The common sense of Franklin, Dalton, Davy, and Black, is the same common sense which made the arrangements which now it discovers.If the identity expresses organized rest, the counter action runs also into organization. The astronomers said, `Give us matter, and a little motion, and we will construct the universe. It is not enough that we should have matter, we must also have a single impulse, one shove to launch the mass, and generate the harmony of the centrifugal and centripetal forces. Once heave the ball from the hand, and we can show how all this mighty order grew.' -- `A very unreasonable postulate,' said the metaphysicians, `and a plain begging of the question. Could you not prevail to know the genesis of projection, as well as the continuation of it?' Nature, meanwhile, had not waited for the discussion, but, right or wrong, bestowed the impulse, and the balls rolled. It was no great affair, a mere push, but the astronomers were right in making much of it, for there is no end to the consequences of the act. That famous aboriginal push propagates itself through all the balls of the system, and through every atom of every ball, through all the races of creatures, and through the history and performances of every individual. Exaggeration is in the course of things. Nature sends no creature, no man into the world, without adding a small excess of his proper quality. Given the planet, it is still necessary to add the impulse; so, to every creature nature added a little violence of direction in its proper path, a shove to put it on its way; in every instance, a slight generosity, a drop too much. Without electricity the air would rot, and without this violence of direction, which men and women have, without a spice of bigot and fanatic, no excitement, no efficiency. We aim above the mark, to hit the mark. Every act hath some falsehood of exaggeration in it. And when now and then comes along some sad, sharp-eyed man, who sees how paltry a game is played, and refuses to play, but blabs the secret; -- how then? is the bird flown? O no, the wary Nature sends a new troop of fairer forms, of lordlier youths, with a little more excess ofdirection to hold themfast to their several aim; makes them a little wrongheaded in that direction in which they are rightest, and on goes the game again with new whirl, for a generation or two more. The child with his sweet pranks, the fool of his senses, commanded by every sight and sound, without any power to compare and rank his sensations, abandoned to a whistle or a painted chip, to a lead dragoon, or a gingerbread-dog, individualizing everything, generalizing nothing, delighted with every new thing, lies down at night overpowered by the fatigue, which this day of continual pretty madness has incurred. But Nature has answered her purpose with the curly, dimpled lunatic. She has tasked every faculty, and has secured the symmetrical growth of the bodily frame, by all these attitudes and exertions, -- an end of the first importance, which could not be trusted to any care less perfect than her own. This glitter, this opaline lustre plays round the top of every toy to his eye, to ensure his fidelity, and he is deceived to his good. We are made alive and kept alive by the same arts. Let the stoics say what they please, we do not eat for the good of living, but because the meat is savory and the appetite is keen. The vegetable life does not content itself with casting from the flower or the tree a single seed, but it fills the air and earth with a prodigality of seeds, that, if thousands perish, thousands may plant themselves, that hundreds may come up, that tens may live to maturity, that, at least, one may replace the parent. All things betray the same calculated profusion. The excess of fear with which the animal frame is hedged round, shrinking from cold, starting at sight of a snake, or at a sudden noise, protects us, through a multitude of groundless alarms, from some one real danger at last. The lover seeks in marriage his private felicity and perfection, with no prospective end; and nature hides in his happiness her own end, namely, progeny, or the perpetuity of the race.But the craft with which the world is made, runs also into the mind and character of men. No man is quite sane; each has a vein of folly in his composition, a slight determination of blood to the head, to make sure of holding him hard to some one point which nature had taken to heart. Great causes are never tried on their merits; but the cause is reduced to particulars to suit the size of the partizans, and the contention is ever hottest on minor matters. Not less remarkable is the overfaith of each man in the importance of what he has to do or say. The poet, the prophet, has a higher value for what he utters than any hearer, and therefore it gets spoken. The strong, self-complacent Luther declares with an emphasis, not to be mistaken, that "God himself cannot do without wise men." Jacob Behmen and George Fox betray their egotism in the pertinacity of their controversial tracts, and James Naylor once suffered himself to be worshipped as the Christ. Each prophet comes presently to identify himself with his thought, and to esteem his hat and shoes sacred. However this may discredit such persons with the judicious, it helps them with the people, as it gives heat, pungency, and publicity to their words. A similar experience is not infrequent in private life. Each young and ardent person writes a diary, in which, when the hours of prayer and penitence arrive, he inscribes his soul. The pages thus written are, to him, burning and fragrant: he reads them on his knees by midnight and by the morning star; he wets them with his tears: they are sacred; too good for the world, and hardly yet to be shown to the dearest friend. This is the man-child that is born to the soul, and her life still circulates in the babe. The umbilical cord has not yetbeen cut. After some time has elapsed, he begins to wish to admit his friend to this hallowed experience, and with hesitation, yet with firmness, exposes the pages to his eye. Will they not burn his eyes? The friend coldly turns them over, and passes from the writing to conversation, with easy transition, which strikes the other party with astonishment and vexation. He cannot suspect the writing itself. Days and nights of fervid life, of communion with angels of darkness and of light, have engraved their shadowy characters on that tear-stained book. He suspects the intelligence or the heart of his friend. Is there then no friend? He cannot yet credit that one may have impressive experience, and yet may not know how to put his private fact into literature; and perhaps the discovery that wisdom has other tongues and ministers than we, that though we should hold our peace, the truth would not the less be spoken, might check injuriously the flames of our zeal. A man can only speak, so long as he does not feel his speech to be partial and inadequate. It is partial, but he does not see it to be so, whilst he utters it. As soon as he is released from the instinctive and particular, and sees its partiality, he shuts his mouth in disgust. For, no man can write anything, who does not think that what he writes is for the time the history of the world; or do anything well, who does not esteem his work to be of importance. My work may be of none, but I must not think it of none, or I shall not do it with impunity.In like manner, there is throughout nature something mocking, something that leads us on and on, but arrives nowhere, keeps no faith with us. All promise outruns the performance. We live in a system of approximations. Every end is prospective of some other end, which is also temporary; a round and final success nowhere. We are encamped in nature, not domesticated. Hunger and thirst lead us on to eat and to drink; but bread and wine, mix and cook them how you will, leave us hungry and thirsty, after the stomach is full. It is the same with all our arts and performances. Our music, our poetry, our language itself are not satisfactions, but suggestions. The hunger for wealth, which reduces the planet to a garden, fools the eager pursuer. What is the end sought? Plainly to secure the ends of good sense and beauty, from the intrusion of deformity or vulgarity of any kind. But what an operose method! What a train of means to secure a little conversation! This palace of brick and stone, these servants, this kitchen, these stables, horses and equipage, this bank-stock, and file of mortgages; trade to all the world, country-house and cottage by the waterside, all for a little conversation, high, clear, and spiritual! Could it not be had as well by beggars on the highway? No, all these things came from successive efforts of these beggars to remove friction from the wheels of life, and give opportunity. Conversation, character, were the avowed ends; wealth was good as it appeased the animal cravings, cured the smoky chimney, silenced the creaking door, brought friends together in a warm and quiet room, and kept the children and the dinner-table in a different apartment. Thought, virtue, beauty, were the ends; but it was known that men of thought and virtue sometimes had the headache, or wet feet, or could lose good time whilst the room was getting warm in winter days. Unluckily, in the exertions necessary to remove these inconveniences, the main attention has been diverted to this object; the old aims have been lost sight of, and to remove friction has come to be the end. That is the ridicule of rich men, and Boston, London, Vienna, and now the。

Ralph Waldo Emerson--Nature

Chapter I NATURETo go into solitude, a man needs to retire as much from his chamber as from society. I am not solitary whilst I read and write, though nobody is with me. Note But if a man would be alone, let him look at the stars. The rays that come from those heavenly worlds, will separate between him and what he touches. One might think the atmosphere was made transparent with this design, to give man, in the heavenly bodies, the perpetual presence of the sublime. Note Seen in the streets of cities, how great they are! If the stars should appear one night in a thousand years, how would men believe and adore; Note and preserve for many generations the remembrance of the city of God which had been shown! But every night come out these envoys of beauty, and light the universe with their admonishing smile. NoteThe stars awaken a certain reverence, because though always present, they are inaccessible; but all natural objects make a kindred impression, when the mind is open to their influence. Note Nature never wears a mean appearance. Note Neither does the wisest man extort her secret, and lose his curiosity Note by finding out all her perfection. Nature never became a toy to a wise spirit. The flowers, the animals, the mountains, reflected the wisdom of his best hour, Note as much as they had delighted the simplicity of his childhood.When we speak of nature in this manner, we have a distinct but most poetical sense in the mind. We mean the integrity of impression made by manifold natural objects. Note It is this which distinguishes the stick of timber of the wood-cutter, from the tree of the poet. The charming landscape which I saw this morning, is indubitably made up of some twenty or thirty farms. Miller owns this field, Locke that, and Manning the woodland beyond. But none of them owns the landscape. There is a property in the horizon which no man has but he whose eye can integrate all the parts, that is, the poet. Note This is the best part of these men's farms, yet to this their warranty-deeds give no title.To speak truly, few adult persons can see nature. Note Most persons do not see the sun. At least they have a very superficial seeing. The sun illuminates only the eye of the man, but shines into the eye and the heart of the child. The lover of nature is he whose inward and outward senses are still truly adjusted to each other; who has retained the spirit of infancy even into the era of manhood. His intercourse with heaven and earth, becomes part of his daily food. In the presence of nature, a wild delight runs through the man, in spite of real sorrows. Nature says, -- he is my creature, and maugre Definition all his impertinent griefs, he shall be glad with me. Not the sun or the summer alone, but every hour and season yields its tribute of delight; for every hour and change corresponds to and authorizes a different state of the mind, Note from breathless noon to grimmest midnight. Nature is a setting that fits equally well a comic or a mourning piece. In good health, the air is a cordial of incredible virtue. Crossing a bare common, in snow puddles, at twilight, under a clouded sky, without having in my thoughts any occurrence of special good fortune, Note I have enjoyed a perfect exhilaration.I am glad to the brink of fear. Note Inthe woods too, a man casts off his years, as the snake his slough Definition, and at what period soever of life, is always a child. Note In the woods, is perpetual youth. Within these plantations of God, a decorum and sanctity reign, a perennial festival is dressed, and the guest sees not how he should tire of them in a thousand years. In the woods, we return to reason and faith. There I feel that nothing can befall me in life, -- no disgrace, no calamity, (leaving me my eyes,) Note which nature cannot repair. Standing on the bare ground, Note -- my head bathed by the blithe air, and uplifted into infinite space, -- all mean egotism vanishes. I become a transparent eye-ball; I am nothing; I see all; the currents of the Universal Being circulate through me; I am part or particle of God. Note The name of the nearest friend sounds then foreign and accidental: to be brothers, to be acquaintances, -- master or servant, is then a trifle and a disturbance. I am the lover of uncontained and immortal beauty.In the wilderness, I find something more dear and connate Note than in streets or villages. In the tranquil landscape, and especially in the distant line of the horizon, man beholds somewhat as beautiful as his own nature. NoteThe greatest delight which the fields and woods minister, is the suggestion of an occult relation between man and the vegetable. Note I am not alone and unacknowledged. They nod to me, and I to them. The waving of the boughs in the storm, is new to me and old. It takes me by surprise, and yet is not unknown. Its effect is like that of a higher thought or a better emotion coming over me, when I deemed I was thinking justly or doing right.Yet it is certain that the power to produce this delight, does not reside in nature, but in man, or in a harmony of both. It is necessary to use these pleasures with great temperance. For, nature is not always tricked in holiday attire, but the same scene which yesterday breathed perfume and glittered as for the frolic of the nymphs, is overspread with melancholy today. Nature always wears the colors of the spirit Note. To a man laboring under calamity, the heat of his own fire hath sadness in it. Then, there is a kind of contempt of the landscape felt by him who has just lost by death a dear friend. Note The sky is less grand as it shuts down over less worth in the population.。

英语专业4级经典美文-95.Nature【声音字幕同步PPT】

His intercourse with heaven and earth, becomes part of his daily food. In the presence of nature,
a wild delight runs through the man, in spite of real sorrows.
but he whose eye can integrate all the parts, that is, the poet.
This is the best part of these men's farms, yet to this their warranty-deeds give no title.
It is this which distinguishes the stick of timber of the wood-cutter, from
the tree of the poet. The charming landscape which I saw this
morning,
is indubitably made up of some twenty or thirty farms.
any occurrence of special good fortune, I have enjoyed a perfect exhilaration. I am glad to the brink of fear.
In the woods too, a man casts off his years, as the snake his slough,
英语专业4级经典美文-95.Nature
: Nature When we speak of nature in this manner, we have a distinct but most poetical sense in the mind.

爱默生《论自然》

The third part(5-6)
• Different environment and mood makes different relationship between people and the nature.
Nature
To go into solitude, a man needs to retire as much from his chamber as from society. I am not solitary whilst I read and write, though nobody is with me. But if a man would be alone, let him look at the stars. The rays that come from those heavenly worlds will separate between him and what he touches.
Nature
In his book, we can feel that he regarded nature as the purest, and the most sanctifying moral influence on man, and advocated a direct intuition of a spiritual and immanent God in nature. Philosophically considered, Emerson thought that the universe is composed of Nature and the Soul. In addition, he paid much attention to the status and role of human beings as well.

nature铝离子电池英文原文An ultrafast rechargeable aluminium-ion battery

An ultrafast rechargeable aluminium-ion batteryMeng-Chang Lin 1,2*,Ming Gong 1*,Bingan Lu 1,3*,Yingpeng Wu 1*,Di-Yan W ang 1,4,5,Mingyun Guan 1,Michael Angell 1,Changxin Chen 1,Jiang Yang 1,Bing-Joe Hwang 6&Hongjie Dai 1The development of new rechargeable battery systems could fuel var-ious energy applications,from personal electronics to grid storage 1,2.Rechargeable aluminium-based batteries offer the possibilities of low cost and low flammability,together with three-electron-redox properties leading to high capacity 3.However,research efforts over the past 30years have encountered numerous problems,such as cathode material disintegration 4,low cell discharge voltage (about 0.55volts;ref.5),capacitive behaviour without discharge voltage plateaus (1.1–0.2volts 6or 1.8–0.8volts 7)and insufficient cycle life (less than 100cycles)with rapid capacity decay (by 26–85per cent over 100cycles)4–7.Here we present a rechargeable aluminium bat-tery with high-rate capability that uses an aluminium metal anode and a three-dimensional graphitic-foam cathode.The battery oper-ates through the electrochemical deposition and dissolution of alu-minium at the anode,and intercalation/de-intercalation of chloroaluminate anions in the graphite,using a non-flammable ionic liquid electrolyte.The cell exhibits well-defined discharge voltage plateaus near 2volts,a specific capacity of about 70mA h g –1and a Coulombic efficiency of approximately 98per cent.The cathode was found to enable fast anion diffusion and intercalation,affording charging times of around one minute with a current densityof 4,000mA g –1(equivalent to 3,000W kg –1),and to withstand more than 7,500cycles without capacity decay.Owing to the low-cost,low-flammability and three-electron redox properties of aluminium (Al),rechargeable Al-based batteries could in principle offer cost-effectiveness,high capacity and safety,which wouldlead to a substantial advance in energy storage technology 3,8.However,research into rechargeable Al batteries over the past 30years has failed to compete with research in other battery systems.This has been due to problems such as cathode material disintegration 4,low cell discharge voltage (,0.55V;ref.5),capacitive behaviour without discharge voltage plateaus (1.1–0.2V,or 1.8–0.8V;refs 6and 7,respectively),and insuf-ficient cycle life (,100cycles)with rapid capacity decay (by 26–85%over 100cycles)4–7.Here we report novel graphitic cathode materials that afford unprecedented discharge voltage profiles,cycling stabilities and rate capabilities for Al batteries.We constructed Al/graphite cells (see diagram in Fig.1a)in Swagelok or pouch cells,using an aluminium foil (thickness ,15–250m m)anode,a graphitic cathode,and an ionic liquid electrolyte made from vacuum dried AlCl 3/1-ethyl-3-methylimidazolium chloride ([EMIm]Cl;see Methods,residual water ,500p.p.m.).The cathode was made from either pyrolytic graphite (PG)foil (,17m m)or a three-dimensional graphitic foam 9,10.Both the PG foil and the graphitic-foam materials exhibited typical graphite structure,with a sharp (002)X-ray diffraction (XRD)graphite peak at 2h <26.55u (d spacing,3.35A˚;Extended Data Fig.1).The cell was first optimized in a Swagelok cell operating at 25u C with a PG foil cathode.The optimal ratio of AlCl 3/[EMIm]Cl was found to be ,1.3–1.5(Extended Data Fig.2a),affording a specific discharging capacity of 60–66mA h g 21(based on graphitic cathode mass)with a Coulombic efficiency of 95–98%.Raman spectroscopy revealed that with an AlCl 3/[EMIm]Cl ratio of ,1.3,both AlCl 42and Al 2Cl 72anions were present (Extended Data Fig.2b)at a ratio [AlCl 42]/[Al 2Cl 72]<2.33*These authors contributed equally to this work.1Department of Chemistry,Stanford University,Stanford,California 94305,USA.2Green Energy and Environment Research Laboratories,Industrial Technology Research Institute,Hsinchu 31040,Taiwan.3School of Physics and Electronics,Hunan University,Changsha 410082,China.4Department of Chemistry,National Taiwan Normal University,Taipei 11677,Taiwan.5Institute of Atomic and Molecular Sciences,Academia Sinica,Taipei 10617,Taiwan.6Department of Chemical Engineering,National Taiwan University of Science and Technology,Taipei 10607,Taiwan.V o l t a g e(V)Time (h)Cycle numberSpecific capacity (mA h g –1)e –4Battery discharging ab c(aluminium)(graphite)C n [AlCl 4] + eC n + AlCl 4EMI +Al 2Cl 74Al 2Cl 7 + 3eAlCl 3/[EMIm]Cl Ionic liquidAl + 7AlCl 43060901201500.00.51.01.52.02.5Charging DischargingV o l t a g e (V )S p e c i fi c c a p a c i t y (m A h g –1)Coulombic efficiency (%)–––––––Figure 1|Rechargeable Al/graphite cell.a ,Schematic drawing of the Al/graphite cell during discharge,using the optimal composition of the AlCl 3/[EMIm]Cl ionic liquid electrolyte.On the anode side,metallic Al and AlCl 4–were transformed into Al 2Cl 7–during discharging,and the reverse reaction took place during charging.On the cathode side,predominantly AlCl 4–wasintercalated and de-intercalated between graphite layers during charge and discharge reactions,respectively.b ,Galvanostatic charge and discharge curves of an Al/pyrolytic graphite (PG)Swagelok cell at a current density of66mA g 21.Inset,charge and discharge cycles.c ,Long-term stability test of an Al/PG cell at 66mA g 21.00M O N T H 2015|V O L 000|N A T U R E |1Macmillan Publishers Limited. All rights reserved©2015(ref.11).The cathode specific discharging capacity was found to be independent of graphite mass (Extended Data Fig.3),suggesting that the entirety of the graphite foil participated in the cathode reaction.The Al/PG cell exhibited clear discharge voltage plateaus in the ranges 2.25–2.0V and 1.9–1.5V (Fig.1b).The relatively high discharge voltage plateaus are unprecedented among all past Al-ion charge-storage sys-tems 4–7.Similar cell operation was observed with the amount of elec-trolyte lowered to ,0.02ml per mg of cathode material (Extended Data Fig.4).Charge–discharge cycling at a current density of 66mA g 21(1C charging rate)demonstrated the high stability of the Al/PG cell,which nearly perfectly maintained its specific capacity over .200cycles with a 98.160.4%Coulombic efficiency (Fig.1c).This was consistent with the high reversibility of Al dissolution/deposition,with Coulombic efficiencies of 98.6–99.8%in ionic liquid electrolytes 12–15.No dendrite formation was observed on the Al electrode after cycling (Extended Data Fig.5).To maintain a Coulombic efficiency .96%,the cut-off voltage of the Al/PG cell (that is,the voltage at which charging was stopped)was set at 2.45V,above which reduced efficiencies were observed (see Extended Data Fig.6a),probably due to side reactions (especially above ,2.6V)involving the electrolyte,as probed by cyclic voltamme-try with a glassy carbon electrode against Al (Extended Data Fig.6b).We observed lowered Coulombic efficiency and cycling stability of the Al/graphite cell when using electrolytes with higher water contents,up to ,7,500p.p.m.(Extended data Fig.6c,d),accompanied by obvious H 2gas evolution measured by gas chromatography (Extended Data Fig.6e).This suggested side reactions triggered by the presence of resi-dual water in the electrolyte,with H 2evolution under reducing poten-tial on the Al side during charging.Further lowering the water contentof the ionic liquid electrolyte could be important when maximizing the Coulombic efficiency of the Al/graphite cells.The Al/PG cell showed limited rate capability with much lower specific capacity when charged and discharged at a rate higher than 1C (Extended Data Fig.7).It was determined that cathode reactions in the Al/PG cell involve intercalation and de-intercalation of relatively large chloroa-luminate (Al x Cl y 2)anions in the graphite (see below for XRD evidence of intercalation),and the rate capability is limited by slow diffusion of anions through the graphitic layers 16.When PG was replaced by nat-ural graphite,intercalation was evident during charging owing to dra-matic expansion (,50-fold)of the cathode into loosely stacked flakes visible to the naked eye (Extended Data Fig.8a).In contrast,expansion of PG foil upon charging the Al/PG cell was not observable by eye (Extended Data Fig.8b),despite the similar specific charging capacity of the two materials (Extended Data Fig.8c).This superior structural integrity of PG over natural graphite during charging was attributed to the existence of covalent bonding between adjacent graphene sheets in PG 17,which was not present in natural ing PG,which has an open,three-dimensionally-bound graphitic structure,we prevented excessive electrode expansion that would lead to electrode disinteg-ration,while maintaining the efficient anion intercalation necessary for high performance.Because high-rate and high-power batteries are highly desirable for applications such as electrical grid storage,the next step in the investi-gation was to develop a cathode material that would have reduced ener-getic barriers to intercalation during charging 16.We investigated a flexible graphitic foam (Fig.2a),which was made on a nickel foam template by chemical vapour deposition 9,10(see Methods),as a possible material fordcbCycle numberSpecific capacity (mA h g –1)a3060901201500.00.51.01.52.02.5Charging DischargingV o l t a g e (V )223.5223.6223.7223.80.00.51.01.52.02.5V o l t a g e (V )Time (h)Cycle numberCoulombic efficiency (%)Coulombic efficiency (%)S p e c i fi c c a p a c i t y (m A h g –1)S p e c i fi c c a p a c i t y (m A h g –1)Figure 2|An ultrafast and stable rechargeable Al/graphite cell.a ,Ascanning electron microscopy image showing a graphitic foam with an open frame structure;scale bar,300m m.Inset,photograph of graphitic foam;scale bar,1cm.b ,Galvanostatic charge and discharge curves of an Al/graphitic-foam pouch cell ata current density of 4,000mA g 21.c ,Long-term stability test of an Al/graphitic-foam pouch cell over 7,500charging and discharging cycles at a current density of 4,000mA g 21.d ,An Al/graphitic-foam pouch cell charging at 5,000mA g 21and discharging at current densities ranging from 100to 5,000mA g 21.LETTER2|N A T U R E |V O L 000|00M O N T H 2015Macmillan Publishers Limited. All rights reserved©2015ultrafast Al batteries.The graphite whiskers in the foam were 100m m in width (Fig.2a),with large spaces in between,which greatly decreased the diffusion length for the intercalating electrolyte anions and facili-tated more rapid battery operation.Remarkably,the Al/graphitic-foam cell (in a pouch cell configuration)could be charged and discharged at a current density up to 5,000mA g 21,about 75times higher (that is,at a 75C rate,,1min charge/discharge time)than the Al/PG cell while maintaining a similar voltage profile and discharge capacity (,60mA h g 21)(Figs 1b and 2b).An impres-sive cycling stability with ,100%capacity retention was observed over 7,500cycles with a Coulombic efficiency of 9762.3%(Fig.2c).This is the first time an ultrafast Al-ion battery has been constructed with stability over thousands of cycles.The Al/graphitic-foam cell retained similar capacity and excellent cycling stability over a range of charge–discharge rates (1,000–6,000mA g 21)with 85299%Coulombic effi-ciency (Extended Data Fig.9a).It was also found that this cell could be rapidly charged (at 5,000mA g 21,in ,1min)and gradually discharged (down to 100mA g 21,Fig.2d and Extended Data Fig.9b)over ,34min while maintaining a high capacity (,60mA h g 21).Such a rapid char-ging/variable discharging rate could be appealing in many real-world applications.We propose that simplified Al/graphite cell redox reactions during charging and discharging can be written as:4Al 2Cl {7z 3e {'Al z 7AlCl {4ð1ÞC n z AlCl {4'C n AlCl 4½ z e{ð2Þwhere n is the molar ratio of carbon atoms to intercalated anions in thegraphite.The balanced AlCl 4–and Al 2Cl 7–concentrations in the electro-lyte allowed for an optimal charging capacity at the cathode,with abun-dant AlCl 4–for charging/intercalation in graphite (equation (2)),and sufficient Al 2Cl 7–concentration for charging/electrodeposition at the anode (equation (1).Ex situ XRD measurement of graphite foil (Fig.3a)confirmed graphite intercalation/de-intercalation by chloroaluminate anions during charging/discharging.The sharp pristine graphite foil (002)peak at2h 526.55u (d spacing 53.35A˚)(Fig.3a)vanished on charging to a specific capacity of ,30mA h g –1,while two new peaks appeared at,28.25u (d <3.15A˚)and ,23.56u (d <3.77A ˚)(Fig.3a),with peak intensities further increasing on fully charging to ,62mA h g –1.The doublet XRD peak suggested highly strained graphene stacks formed on anion intercalation 18.Analysis of the peak separation (see Methods)suggested a stage 4graphite intercalation compound with an interca-lant gallery height (spacing between adjacent graphitic host layers)of,5.7A˚,indicating that the AlCl 4–anions (size ,5.28A ˚;ref.19)were intercalated between graphene layers in a distorted state.Full dischar-ging led to the recovery of the graphite peak but with a broad shoulder (Fig.3a),probably caused by irreversible changes in the stacking between the graphene layers or a small amount of trapped species.In situ Raman spectroscopy was also performed to probe chloroalu-minate anion intercalation/de-intercalation from graphite during cell charge/discharge (Fig.3b).The graphite G band (,1,584cm –1)diminished and split into a doublet (1,587cm –1for the E 2g2(i)mode and ,1,608cm –1for the E 2g2(b)mode)upon anion intercalation (Fig.3b)20,and then evolved into a sharp new peak (,1,636cm –1,the G2band of the E 2g2(b)mode,spectrum 2.41V,Fig.3b)once fully charged.The spectral changes were then reversed upon discharging (Fig.3b),as the typical graphite Raman G band (1584cm –1)was recovered when fully discharged (spectrum 0.03V,Fig.3b).Similar Raman spectra and XRD data were obtained with a graphitic-foam cathode (Extended Data Fig.10a,b).Interestingly,calcination of a fully charged PG foil at 850u C in air (Fig.3c)yielded a white aluminium oxide foam (Extended Data Fig.10c),confirming the intercalation of chloroaluminate anions into the carbon network,which had been evi-dently removed oxidatively.Lastly,X-ray photoelectron spectra (XPS)and Auger electron spec-troscopy (AES)were performed to probe the chemical nature of the intercalated species in our graphitic cathodes (see Methods for details).To minimize the amount of trapped electrolyte,graphitic foam was used and the electrode was thoroughly washed with anhydrous methanol.XPS revealed that upon charging pristine graphite,the 284.8eV C 1s peak developed a shoulder at higher energy (,285.9eV,Fig.4a),con-firming electrochemical oxidation of graphitic carbon by intercalation of AlCl 4–anions (equation (2)).Chloroaluminate intercalation was evi-dent from the appearance of Al 2p and Cl 2p peaks (Fig.4b,c).UponFully charged PG850°C in aircba20253035discharged chargedcharged 30 mA h g 24 mA h g I n t e n s i t y (a .u .)62 mA h g Pristinedischarged 60 mA h g 3.77 Å3.35 Å3.15 ÅSecond cycleI n t e n s i t y (a .u .)Raman shift (cm –1)2q (degrees)Figure 3|Al/graphite cell reaction mechanisms.a ,Ex situ X-ray diffraction patterns of PG in various charging and discharging states through the second cycle.b ,In situ Raman spectra recorded for the PG cathode through a charge–discharge cycle,showing chloroaluminate anion intercalation/de-intercalation into graphite.c ,After calcination of a fully charged(62mA h g 21)PG electrode at 850u C in air,the sample completely transformed into a white foam made of aluminium oxide.Scale bar,1cm.I n t e n s i t y (a .u .)Binding energy (eV)4008001,2001,6002,000–2.0–1.00.01.02.0C l OC d N (E )/d E (×104)d N (E )/d E (×104)Kinetic energy (eV)AlDischarged cathodeCharged cathodeC+Al+Clf edgcKinetic energy (eV)Figure 4|Chemical probing of a graphitic cathode by XPS and AES.a ,XPS data of the C 1s peak of a graphitic-foam electrode:pristine,fully charged and fully discharged.b ,c ,XPS data of Al 2p and Cl 2p peaks observed with a graphitic-foam electrode:pristine,fully charged and fully discharged.d–g ,AES mapping images for C,Al and Cl (d ,f ),and the AES spectrum of the boxed regions (e ,g )obtained with a fully charged graphitic-foam sample (d ,e )and a fully discharged graphitic-foam sample (f ,g ).Scale bars:d ,25m m;f ,10m m.LETTER 00M O N T H 2015|V O L 000|N A T U R E |3Macmillan Publishers Limited. All rights reserved©2015discharging,the C1s XPS spectrum of the cathode reverted to that of the pristine graphite due to anion de-intercalation and carbon reduc-tion(Fig.4a).Also,a substantial reduction in the Al2p and Cl2p signals was recorded over the graphite sample(see Fig.4b,c).The remaining Al and Cl signals observed were attributed to trapped/adsorbed species in the graphite sample,which was probed by XPS over a large area.Fur-thermore,high spatial resolution AES elemental mapping of a single graphite whisker in the fully charged graphitic foam clearly revealed Al and Cl Auger signals uniformly distributed over the whisker(Fig.4d,e), again confirming chloroaluminate anion intercalation.When fully dis-charged,AES mapping revealed anion de-intercalation from graphite with much lower Al and Cl Auger signals observed(Fig.4f,g).These spectroscopic results clearly revealed chloroaluminate ion intercala-tion/de-intercalation in the graphite redox reactions involved in our rechargeable Al cell.The Al battery pouch cell is mechanically bendable and foldable(Sup-plementary Video1)owing to the flexibility of the electrode and sepa-rator materials.Further,we drilled through Al battery pouch cells during battery operation and observed no safety hazard,owing to the lack of flammability of the ionic liquid electrolyte in air(see Supplementary Video2).We have developed a new Al-ion battery using novel graphitic cath-ode materials with a stable cycling life up to7,500charge/discharge cycles without decay at ultrahigh current densities.The present Al/graphite battery can afford an energy density of,40W h kg–1(comparable to lead–acid and Ni–MH batteries,with room for improvement by opti-mizing the graphitic electrodes and by developing other novel cathode materials)and a high power density,up to3,000W kg–1(similar to super-capacitors).We note that the energy/power densities were calculated on the basis of the measured,65mA h g–1cathode capacity and the mass of active materials in electrodes and electrolyte.Such recharge-able Al ion batteries have the potential to be cost effective and safe,and to have high power density.Online Content Methods,along with any additional Extended Data display items and Source Data,are available in the online version of the paper;references unique to these sections appear only in the online paper.Received12March2014;accepted6February2015.Published online6April2015.1.Yang,Z.et al.Electrochemical energy storage for green grid.Chem.Rev.111,3577–3613(2011).2.Huskinson,B.et al.A metal-free organic-inorganic aqueous flow battery.Nature505,195–198(2014).3.Li,Q.&Bjerrum,N.J.Aluminum as anode for energy storage and conversion:areview.J.Power Sources110,1–10(2002).4.Gifford,P.R.&Palmisano,J.B.An aluminum/chlorine rechargeable cellemploying a room temperature molten salt electrolyte.J.Electrochem.Soc.135, 650–654(1988).5.Jayaprakash,N.,Das,S.K.&Archer,L.A.The rechargeable aluminum-ion 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and its cycling efficiencies.J.Electrochem.Soc.132, 598–601(1985).13.Wilkes,J.S.,Levisky,J.A.,Wilson,R.A.&Hussey,C.L.Dialkylimidazoliumchloroaluminate melts:a new class of room-temperature ionic liquids forelectrochemistry,spectroscopy and synthesis.Inorg.Chem.21,1263–1264(1982).i,P.K.&Skyllas-Kazacos,M.Electrodeposition of aluminium in aluminiumchloride/1-methyl-3-ethylimidazolium chloride.J.Electroanal.Chem.Interfacial Electrochem.248,431–440(1988).15.Jiang,T.,Chollier Brym,M.J.,Dube´,G.,Lasia,A.&Brisard,G.M.Electrodeposition ofaluminium from ionic liquids:Part I—electrodeposition and surface morphology of aluminium from aluminium chloride(AlCl3)–1-ethyl-3-methylimidazolium chloride([EMIm]Cl)ionic liquids.Surf.Coat.Tech.201,1–9(2006).16.Borg,R.J.&Dienes,G.J.An Introduction to Solid State Diffusion(Academic,1988).17.Zhu,Y.-J.,Hansen,T.A.,Ammermann,S.,McBride,J.D.&Beebe,T.P.Nanometer-size monolayer and multilayer molecule corrals on HOPG:a depth-resolvedmechanistic study by 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Acknowledgements We thank M.D.Fayer for discussions.We also thank Y.Cui’s group for use of an argon-filled glove box and a vacuum oven.M.-C.L thanks the Bureau of Energy,Ministry of Economic Affairs,Taiwan,for supporting international cooperation between Stanford University and ITRI.B.L.acknowledges support from the National Natural Science Foundation of China(grant no.21303046),the China Scholarship Council(no.201308430178),and the Hunan University Fund for Multidisciplinary Developing(no.531107040762).We also acknowledge support from the US Department of Energy for novel carbon materials development and electrical characterization work(DOE DE-SC0008684),Stanford GCEP,the Precourt Institute of Energy,and the Global Networking Talent3.0plan(NTUST104DI005)from the Ministry of Education of Taiwan.Author Contributions M.-C.L.,M.G.,B.L.and Y.W.contributed equally to this work. M.-C.L.and H.D.conceived the idea for the project.B.L.prepared the graphitic foam. M.-C.L.,M.G.,B.L.,Y.W.,D.-Y.W.,M.A.and M.Guan performed electrochemical experiments.M.-C.L.,C.C.and J.Y conducted in situ Raman spectroscopy measurements.M.-C.L.,M.G.,B.L.and Y.W.performed ex situ X-ray diffraction measurements.M.G.,M.-C.L.,B.L.and Y.W.performed X-ray photoelectron spectroscopy and Auger electron spectroscopy measurements.M.-C.L.,M.G.,B.L.,Y.W., D.-Y.W.,M.A.,B.-J.H.and H.D.discussed the results,analysed the data and drafted the manuscript.Author Information Reprints and permissions information is available at/reprints.The authors declare no competing financial interests. Readers are welcome to comment on the online version of the paper.Correspondence and requests for materials should be addressed to H.D.(hdai@).LETTER4|N A T U R E|V O L000|00M O N T H2015Macmillan Publishers Limited. All rights reserved©2015METHODSPreparation of ionic liquid electrolytes.A room temperature ionic liquid electro-lyte was made by mixing1-ethyl-3-methylimidazolium chloride([EMIm]Cl,97%, Acros Chemicals)and anhydrous aluminium chloride(AlCl3,99.999%,Sigma Aldrich).[EMIm]Cl was baked at130u C under vacuum for16–32h to remove residual water.([EMIm]Al x Cl y)ionic liquid electrolytes were prepared in an argon-atmosphere glove box(both[EMIm]Cl and AlCl3are highly hygroscopic)by mix-ing anhydrous AlCl3with[EMIm]Cl,and the resulting light-yellow,transparent liquid was stirred at room temperature for10min.The mole ratio of AlCl3to[EMIm]Cl was varied from1.1to1.8.The water content of the ionic liquid was determined (500–700p.p.m.)using a coulometric Karl Fischer titrator,DL39(Mettler Toledo). The predominant anions in basic melts(AlCl3/[EMIm]Cl mole ratio,1)are Cl2 and AlCl42,while in acidic melts(AlCl3/[EMIm]Cl mole ratio.1)chloroalumi-nate anions such as Al2Cl72,Al3Cl102,and Al4Cl132are formed11.The ratio of anions to cations in the AlCl3/[EMIm]Cl electrolyte was determined using a glass fibre filter paper(Whatman GF/D)loaded with a4–8m m Au-coated SiO2beads21in a cuvette cell(0.35ml,Starna Cells)with random orientation quartz windows.Then,in the glove box,the cuvette cell was filled with AlCl3/[EMIm]Cl51.3(by mole).Raman spectra(200–650cm-1)were obtained using a785-nm laser with2cm–1resolution. Raman data were collected from the surface of the Au-coated SiO2bead so as to benefit from surface enhanced Raman21,22(Extended Data Fig.2b). Preparation of graphitic foam.Nickel(Ni)foams(Alantum Advanced Technology Materials,Shenyang,China),were used as3D scaffold templates for the CVD growth of graphitic foam,following the process reported previously9,10. The Ni foams were heated to1,000u C in a horizontal tube furnace(Lindberg Blue M,TF55030C)under Ar(500standard cubic centimetres per minute or s.c.c.m.)and H2(200s.c.c.m.)and annealed for10min to clean their surfaces and to eliminate a thin surface oxide layer.Then,methane(CH4)was introduced into the reaction tube at ambient pressure at a flow rate of10s.c.c.m.,corresponding to a concen-tration of1.4vol.%in the total gas flow.After10min of reaction gas mixture flow, the samples were rapidly cooled to room temperature at a rate of300u C min21 under Ar(500s.c.c.m.)and H2(200s.c.c.m.).The Ni foams covered with graphite were drop-coated with a poly(methyl methacrylate)(PMMA)solution(4.5%in ethyl acetate),and then baked at110u C for0.5h.The PMMA/graphene/Ni foam structure was obtained after solidification.Afterwards,these samples were put into a3M HCl solution for3h to completely dissolve the Ni foam to obtain the PMMA/graphite at80u C.Finally,the pure graphitic foam was obtained by removing PMMA in hot acetone at55u C and annealing in NH3(80s.c.c.m.)at 600u C for2h,and then annealing in air at450u C for2h.The microstructure of the graphitic foam was examined by SEM analysis using a FEI XL30Sirion scanning electron microscope(Fig.2a in the main text).Preparation of glassy carbon.Glassy carbon(GC)was used as the current collector in the Swagelok-type cell.72g phenol(Sigma-Aldrich)and4.5ml ammonium hydroxide(30%,Fisher Scientific)were dissolved in100ml formaldehyde solution (37%,Fisher Scientific)under reflux while stirring rapidly.The solution was stirred at90u C until the solution turned a milk-white colour.Rotary evaporation was used to remove the water and get the phenolic resin.The phenolic resin was solidified at 100u C in a mould(1/2-inch glass tube),and then carbonized at850u C under an Ar atmosphere for four hours to obtain the GC rod.The resulting GC rod contributed negligible capacity to the cathode(Extended Data Fig.6b).Electrochemical measurements.Prior to assembling the Al/graphite cell in the glove box,all components were heated under vacuum at60u C for more than12h to remove residual water.All electrochemical tests were performed at2561u C.A Swagelok-type cell(1/2inch diameter)was constructed using a,4mg PG foil(0.017mm,Suzhou Dasen Electronics Materials)cathode and a90mg Al foil (0.25mm,Alfa Aesar)anode.A1/2inch GC rod(10mm)was used as the current collector for the PG cathode,and a1/2inch graphite rod(10mm)was used for the Al anode.Six layers of1/2inch glass fibre filter paper(Whatman934-AH)were placed between the anode and cathode.Then,,1.0ml of ionic liquid electrolyte (prepared with AlCl3/[EMIm]Cl mole ratios of1.1,1.3,1.5and1.8)was injected and the cell sealed.The Al/PG cell was then charged(to2.45V)and discharged(to 0.01V)at a current density of66mA g–1with a MTI battery analyser(BST8-WA) to identify the ideal AlCl3/[EMIm]Cl mole ratio(Extended Data Fig.2a).To investigate the Coulombic efficiency of the Al/PG cell in AlCl3/[EMIm]Cl<1.3 (by mole)electrolyte,the cell was charged to2.45,2.50,2.55and2.60V,respectively, and discharged to0.4V at a current density of66mA g–1(Extended Data Fig.6a). For long-term cycling stability tests,an Al/PG cell using electrolyte AlCl3/ [EMIm]Cl<1.3by mole was charged/discharged at a current density of 66mA g21(Fig.1b,c in the main text).To study the rate capability of the Al/ PG cell,the current densities were varied from66to264mA g21(Extended Data Fig.7).Note that we lowered the electrolyte amount to,0.02ml per mg of cathode material and observed similar cell operation(Extended Data Fig.4). Further decrease in the electrolyte ratio is possible through battery engineering.PG foil was synthesized by pyrolysis of polyimide at high temperature,in which some covalent bonding is inevitably generated due to imperfections.Natural graphite foil was produced by compressing expanded graphite flakes,leading to stacking of natural graphite flakes by Van der Waals bonding between them.Similar battery characteristics were observed with PG and graphite foil electrodes,indicating that the battery behaviour was derived from the graphitic property of the electrodes (Extended Data Fig.8c).However,since the natural graphite foils are synthesized by compressing expanded natural graphite powders without the covalent linkage between them,these foils suffered from drastic electrode expansion obvious to the naked eye,whereas pyrolytic graphite foils showed no obvious electrode expan-sion due to covalency(Extended Data Fig.8a,b).Pouch cells were assembled in the glove box using a graphitic-foam(,3mg) cathode and an Al foil(,70mg)anode,which were separated by two layers of glass fibre filter paper to prevent shorting.Polymer(0.1mm34mm35mm)coated Ni foils(0.09mm33mm360mm in size;MTI corporation)were used as current collectors for both anode and cathode.The electrolyte(,2ml prepared using AlCl3/[EMIm]Cl51.3by mole)was injected and the cell was closed using a heat sealer.The cell was removed from the glove box for long-term cycling stability tests,in which the cell was charged/discharged at a current density of4,000mA g21 (Fig.2b,c).To determine the rate capability and fast-charge/slow-discharge beha-viours of the Al/graphitic-foam cell,various current densities from100to 5,000mA g21were used(Extended Data Fig.9and Fig.2d).The pouch cell was charged to2.42V and discharged to a cut-off voltage of0.5V to prevent the dissolution reaction of Ni foil in the ionic liquid electrolyte.Cyclic voltammetry measurements were performed using a potentiostat/galva-nostat model CHI760D(CH Instruments)in either three-electrode or two-electrode mode.The working electrode was an Al foil or a PG foil,the auxiliary electrode consisted of an Al foil,and an Al foil was used as the reference electrode.Copper tape(3M)was attached to these electrodes as the current collector.The copper tape was covered by poly-tetrafluoroethylene(PTFE)tape to prevent contact with the ionic liquid electrolyte and the part of the copper tape covered by PTFE was not immersed in the ionic liquid electrolyte.This prevented corrosion of the copper tape during cyclic voltammetry measurements.All three electrodes were placed in a plastic(1.5ml)cuvette cell(containing electrolyte AlCl3/ [EMIm]Cl51.3by mole)in the glove box,and then sealed with a rubber cap using a clamp.The scanning voltage range was set from–1.0to1.0V(versus Al) for Al foil and0to2.5V(versus Al)for graphitic material,and the scan rate was 10mV s–1(Extended Data Fig.10d).To investigate the working voltage range of the electrolyte without involving cathode intercalation,two-electrode measurement was performed by using a GC rod cathode against an Al anode in a Swagelok cell in AlCl3/[EMIm]Cl(,1.3by mole)electrolyte.The scanning voltage range was set from0to2.9V at a scan rate of10mV s–1(Extended Data Fig.6b).We investigated the Al ion cell operation mechanism and electrode reactions in the ionic liquid electrolyte,using the optimal mole ratio of AlCl3/[EMIm]Cl51.3. Using CV(Extended Data Fig.10d),a reduction wave from–1.0to–0.08V(versus Al)and an oxidation wave from20.08to0.80V(versus Al)for the anode were observed(Extended Data Fig.10d,left plot),corresponding to Al reduction/elec-trodeposition and oxidation/dissolution13,15,23–25during charging and discharging, respectively.This was consistent with Al redox electrochemistry in chloroalumi-nate ionic liquids13,15,23–25via equation(1)in the main text,and consistent with our Raman measurements,which showed both AlCl42and Al2Cl72in the electrolyte (Extended Data Fig.2b).On the graphitic cathode side,an oxidation wave of1.83 to2.50V(versus Al)and a reduction wave of1.16to2.36V(versus Al)were observed (Extended Data Fig.10d,right plot)and attributed to graphite oxidation and reduc-tion through intercalation and de-intercalation of anions(predominantly AlCl42 due to its smaller size),respectively.The oxidation voltage range of1.83to2.50V (versus Al,Extended Data Fig.10d,right plot)was close to the anodic voltage range (1.8to2.2V versus Al)of a previously reported dual-graphite cell26attributed to AlCl42intercalation in graphite.The reduction wave range of1.16to2.36V(versus Al)was assigned to the AlCl42de-intercalation26.The nature of the shoulder in the reduction curve of graphite ranging from2.36to1.9V(Extended Data Fig.10d, right plot)and a higher discharge plateau(2.25to2.0V)of an Al/PG cell upon charging(Fig.1b in the main text)remained unclear,but could be due to different stages of anion–graphite intercalation27.XRD and Raman studies of graphite cathodes during charge and discharge. For ex situ X-ray diffraction(XRD)study,an Al/PG cell(in a Swagelok configu-ration)was charged and discharged at a constant current density of66mA g–1.The reactions were stopped after30mA h g–1charged,fully charged(62mA h g–1)and 40mA h g–1discharged after charge/discharge capacities were in a stable state.Fully charged(62mA h g–1)graphitic foam was also prepared.After either the charge or the discharge reaction,the graphitic cathode was removed from the cell in the glove box.To avoid reaction between the cathode and air/moisture in the ambient atmo-sphere,the cathode was placed onto a glass slide and then wrapped in a Scotch tape.LETTERMacmillan Publishers Limited. All rights reserved ©2015。

dqn算法nature原文

dqn算法nature原文英文回答：Deep Q-Network (DQN) is a reinforcement learning algorithm that combines deep neural networks with Q-learning. It was introduced by Mnih et al. (2015) and has since become one of the most popular RL algorithms.DQN works by approximating the action-value function (Q-function) using a deep neural network. The Q-function is a function that estimates the expected long-term reward for taking a particular action in a given state.To train the DQN, a replay buffer is used to store past experiences. The network is then trained on batches of experiences from the replay buffer. The loss function used to train the network is the mean squared error between the predicted Q-values and the target Q-values.The target Q-values are calculated using the Bellmanequation:Q(s, a) = r + γ max_a' Q(s', a')。

nature文章中英文本

nature文章中英文本NatureNature is a magnificent gift bestowed upon us by the universe. It is a source of inspiration, beauty, and tranquility. From the towering mountains to the vast oceans, nature encompasses a wide array of landscapes that captivate our senses and ignite our imagination.In the hustle and bustle of modern life, it is easy to forget the importance of connecting with nature. We are often consumed by our daily routines and responsibilities, leaving little time to appreciate the wonders that surround us. However, taking the time to immerse ourselves in nature can have profound effects on our well-being.When we venture into the great outdoors, we are greeted by a symphony of sights, sounds, and smells. The vibrant colors of blooming flowers, the gentle rustling of leaves in the wind, and the sweet fragrance of fresh air all work together to create a sensory experience like no other. These natural stimuli have a calming effect on our minds, allowing us to escape the stresses of everyday life and find solace in the beauty of the world around us.Moreover, nature has the power to heal. Numerous studies have shown that spending time in nature can reduce stress, anxiety, and depression. The tranquility and serenity of natural environments have a soothing effect on our minds, helping us to find inner peace and balance. Whether it is a leisurely walk in the park or a hike through the wilderness, immersing ourselves in nature allows us to recharge and rejuvenate our spirits.In addition to its therapeutic benefits, nature also serves as a source of inspiration for artists, writers, and scientists alike. The intricate patterns found in a seashell, the graceful flight of a bird, or the delicate petals of a flower all provide endless inspiration for creative minds. Nature's beauty and complexity have sparked countless scientific discoveries and artistic masterpieces throughout history.However, as our world becomes increasingly urbanized, we are losing touch with nature at an alarming rate. Concrete jungles are replacing lush green forests, and pollution is choking our rivers and oceans. It is crucial that we recognize the importance of preserving and protecting our natural environment for future generations.Fortunately, there is a growing movement towards environmental conservation and sustainability. People are becoming more aware of the impact of their actions on the planet and are taking steps to reduce their carbon footprint. From recycling and using renewable energy sources to supporting conservation efforts, individuals and communities are coming together to protect our precious natural resources.In conclusion, nature is a priceless treasure that we must cherish and protect. It provides us with solace, inspiration, and a sense of wonder. By reconnecting with nature and taking steps to preserve it, we can ensure that future generations will be able to enjoy its beauty and benefits. Let us embrace the power of nature and work together to create a sustainable and harmonious relationship with the natural world.。

Unit 17 Nature

Unit 17 NatureNature, the vast and wonderful world that surrounds us, is a source of endless mystery and beauty It is the home of countless species, the provider of essential resources, and the stage upon which the drama of life unfoldsThe beauty of nature is breathtaking Think about the mountains, standing tall and majestic, their peaks touching the clouds Their slopes are covered with lush forests, where the trees stand like silent guardians The rivers that flow down the mountains, carrying clear water that sparkles in the sunlight, are like ribbons of life The sound of the rushing water, the chirping of the birds, and the rustling of the leaves in the wind create a symphony that soothes our soulsThe diversity of nature is truly astonishing From the tiniest microorganisms to the largest mammals, every living being has its unique role and place in the ecosystem Take the coral reefs, for example They are home to a myriad of colorful fish, delicate sea anemones, and complex marine organisms Each one of them has adapted to the specific conditions of the reef, creating a delicate balance that is both fragile and resilientNature also has a profound impact on our wellbeing Spending time in nature can reduce stress, improve our mood, and enhance our physical health Just a walk in the park, breathing in the fresh air, and feeling the grass under our feet can do wonders for our mental state The natural light and the connection with the outdoors can boost our immune system and increase our energy levelsHowever, despite its importance and beauty, nature is facing numerous threats Human activities such as deforestation, pollution, and overfishing are taking a toll on the natural world Forests are being cleared at an alarming rate to make way for agriculture and urban development This not only leads to the loss of habitat for countless species but also contributes to climate change as trees, which act as carbon sinks, are being removedPollution is another major concern The air we breathe, the water we drink, and the soil that grows our food are all contaminated to varying degrees Chemicals from factories, pesticides from agriculture, and plastic waste from our daily lives are poisoning the environment and harming wildlifeOverfishing is depleting our oceans' fish populations, disrupting the marine food chain and threatening the livelihoods of communities that depend on fishing The use of unsustainable fishing methods such as bottom trawling and longline fishing is causing significant damage to the ocean floor and marine ecosystemsIt is our responsibility to protect and preserve nature for future generations We need to adopt sustainable practices in our daily lives This can include reducing our consumption of singleuse plastics, conserving energy, and choosing products that are environmentally friendly We should also support policies and initiatives that aim to protect natural habitats and wildlifeEducation plays a crucial role in raising awareness about the importance of nature By teaching children and adults about the wonders of the naturalworld and the consequences of our actions, we can inspire them to become stewards of the environmentIn conclusion, nature is not just a backdrop to our lives; it is an integral part of our existence We must recognize its value and take action to protect it Only by doing so can we ensure that the beauty and diversity of nature continue to thrive for generations to come Let us all do our part to safeguard this precious gift that nature has bestowed upon us。

nature 短文

nature 短文Nature is a magnificent creation that encompasses all forms of life and the environment that surrounds it. It is a constantly changing canvas, with each season bringing a new set of colors and textures. From the smallest blade of grass to the mightiest mountain, nature is a masterpiece that never ceases to inspire.The beauty of nature is not just in its visual splendor, but also in its ability to evoke emotions and memories. It is the place where we seek solitude, find peace, and rejuvenate our spirits. It is the backdrop for our most cherished moments and the setting for our fondest memories.The serene landscape of a meadow, with its rolling hills and vibrant flowers, offers a sense of tranquility. The roar of a waterfall, as it plunges over a precipice, stirs the soul. The rustling of leaves in the wind and the melody of birdsong create a symphony that soothes the mind.Nature also teaches us valuable lessons about life and the world around us. It demonstrates the power of adaption, the resilience of the natural world, and the importance of balanceand harmony. It is a testament to the wonders of creation and a reminder of our place within the vast interconnected web of life.In conclusion, nature is not just a beautiful backdrop for our lives, it is an essential part of our existence. It provides us with both physical and emotional sustenance and has the unique ability to bring us closer to our inner selves. It is a constant reminder to appreciate the world around us and to cherish the gift of life.。

中国第一篇《Nature》！

中国第⼀篇《Nature》！图⽚来源：⽹络来源：学术志、材料基、SME科技故事、姚远科学⽹博客能够在CNS（Cell+Nature+Science）等国际⼀流核⼼期刊上发表论⽂，作为科研⼈员，简直孜孜以求，其实，早在138年前的清朝末期，中国⼈就在《Nature》上发表了第⼀篇论⽂《考证律吕说》。

Nature杂志由英国Nature Publishing Group创刊于1869年，是世界上最早的国际性、综合性科学技术期刊。

《考证律吕说》登载于《格致汇编》1878年第7卷，后由《格致汇编》的主编傅兰雅（John Fryer,1839—1928）译为英⽂在Nature发表，这也是中国科学家在Nature发表的第⼀篇论⽂。

⽂章纠正了著名的伯努利定律，引起了国际巨⼤的反响，nature编辑评价道:'这⾮常出奇'，也是这篇⽂章，使得Nature创办以来，第⼀次出现了中国⼈的名字。

其作者就是被称为晚清科技总设计师，启蒙了整个中国近代科学的徐寿。

徐寿（1818—1884），号雪村，1818年出⽣于江苏⽆锡⼀个没落的地主家，5岁丧⽗。

除了是第⼀个发《Nature》的中国⼈，徐寿还有许多与清朝格格不⼊的“第⼀”。

中国第⼀台蒸汽机、第⼀艘轮船、第⼀艘军舰、第⼀所教授科技知识的学校、第⼀场科学讲座、第⼀本科技期刊、第⼀批化学翻译本...徐寿，号雪村，1818年出⽣于江苏⽆锡⼀个没落的地主家。

虽5岁丧⽗，但他的母亲仍对他要求⼗分严格，望他⽇后⾼中状元，讨个官做。

徐寿所以⾃幼聪颖的徐寿，不但饱读诗书，还对这些古⽂有许多⾃⼰独特见解。

⽆论是母亲，还是外⼈，都对他赞不绝⼝。

然⽽，在旧式的“童⼦举”中，他竟连个秀才都没考上。

不久后，母亲的去世，也让他更加痛觉学习⼋股⽂的⽆⽤。

在这之后，他便毅然放弃了“应试教育”和科举当官的打算，开始通往“经世致⽤”之学——科学。

他涉猎的科技范围极⼴，律吕（⾳乐）、⼏何、重学（⼒学）、矿产、汽机、医学、光学、电学，就没有⼀样是他不喜欢的。

美国文学nature

NATURE①What is Transcendentalism?(超验主义)Transcendentalism was a literary movement that flourished during the middle 19th century (1836-1860).It began as a rebellion against traditionally held beliefs by English Church that God superseded the individual. It began as a rebellion against traditionally held beliefs by the English Church that God superseded the individuals. it stressed intuitive understanding of god without the help of the church, and advocated independence of the mind. .Transcendentalists departed from orthodox Calvinism in that they believed in the importance and efficacy of human striving, as opposed to the bleaker Puritan picture of complete and inescapable human depravity.②Core Beliefs of Transcendentalism(超验主义的核心理念)1: Finding its root in the word “transcend”.Transcendentalists believed individuals could transcend to a higher being of existence in nature.2: God is located in the soul of each individual.3: Humanity’s potential is limitless.4: Experience is valued over scholarship.5: For the transcendentalists, the soul of each individual is identical with the soul of the world and contains what the world contains.③Nature expresses the main principles of Transcendentalism.1:lover of nature2:the”uses”of nature3:Commodity4:Beauty5:Language6:Discipline7: unity of nature8:Over-soul④His attitude towards nature:Emerson loves nature. His nature is the garment of the over-soul, symbolic and moral bound. Nature is not something purely of the matter, but alive with God’s presence. It exercises a healthy and restorative influence on human beings. Children can see nature better than adult.⑤Nature1: In 1836, his first work, Nature 《论自然》was published , which epitomized(称为缩影)the main doctrines of his philosophy, his theories and his belief in the progress of man and society.2: The essay consists of the introduction part and eight chapters. They are Nature, Commodity, Beauty, Language, Discipline, Idealism, Spirit and Prospects respectively.⑥The structure1: The first part (1—3):Introduce the topics that the power of the nature is very great.2: The second part(4):Few people could realize the beauty of the nature and talk about what kind of person could find the beauty.3: The third part(5—6):Different environment and mood makes different relationship between people and the nature.⑦The content and the translation:1:To go into solitude, man needs to retire as much from his chamber as from society.Ⅰ: 为了寻得孤身独处�人有必要走出书斋退出社会�回归自然。

nature审稿邮件原文

nature审稿邮件原文Nature审稿邮件原文尊敬的作者，感谢您将您的研究成果提交到Nature。

我们非常重视您的工作，并且经过我们编辑团队的认真审核，我们决定为您的研究提供一个机会进行进一步评估。

您的研究题目非常引人注目，我们对您的工作表现出浓厚的兴趣。

在您的研究中，您详细描述了大自然的奇妙之处，并对生物多样性的保护和环境可持续性提出了重要观点。

您的研究对于我们理解和保护自然世界的重要性具有巨大的价值。

在文章中，您通过对不同地理区域的自然环境进行详细的观察和分析，揭示了自然界的美妙和复杂性。

您的描述让读者仿佛亲身体验了大自然的壮丽景观，感受到了大自然的力量和神秘。

在文章的结构上，您将内容分为了多个部分，每个部分都清晰地呈现了不同的观点和实验结果。

每个段落都有适当的标题，使得读者能够轻松地理解和跟随您的思路。

这种结构合理性使得整篇文章更加连贯和易读。

在语言运用方面，您的句式流畅，用词丰富多样。

您恰如其分地运用了各种修辞手法和形象的比喻，使得文章更具有感染力和吸引力。

您的描述让读者产生了强烈的共鸣，仿佛置身于大自然之中，亲眼目睹了您所描绘的美景。

我们也注意到您在文章中避免了使用网络链接和数学公式。

这样的做法使得文章更加清晰简洁，同时也避免了读者在阅读过程中的干扰和困惑。

在最后，我们想提醒您在文章中避免重复提出同一个问题，并且不要过多地自我介绍。

同时，您还需注意确保文章内容的准确性和严肃性，避免歧义或误导的信息。

我们希望您能够继续深入研究，为我们认识和保护自然界做出更大的贡献。

再次感谢您选择Nature来分享您的研究成果。

我们期待看到您对于自然界的进一步探索和发现。

如果您对我们的评估结果有任何疑问或建议，请随时与我们联系。

祝好！。

nature审稿邮件原文

nature审稿邮件原文摘要：I.引言- 介绍Nature期刊审稿邮件的原文II.Nature期刊审稿流程简介- 简要介绍Nature期刊的审稿流程III.审稿邮件原文概述- 总结审稿邮件的主要内容IV.审稿邮件原文详细解读- 详细分析审稿邮件的各个部分V.对审稿意见的回应与建议- 提出对审稿意见的回应和修改建议VI.结论- 总结文章的主要观点和信息正文：【引言】ature期刊是世界上最著名、最具影响力的科学期刊之一。

在Nature上发表论文是许多科研人员的梦想。

然而，想要在Nature上发表论文并不容易，需要经过严格的审稿流程。

在这个过程中，审稿人的意见对论文的修改和改进起到至关重要的作用。

今天，我们将通过分析一篇Nature审稿邮件的原文，来了解Nature期刊的审稿流程以及如何回应审稿意见。

【Nature期刊审稿流程简介】ature期刊的审稿流程可以分为以下几个阶段：作者投稿、编辑筛选、送审、审稿人审稿、作者回应审稿意见、编辑决定、最终稿件确认和发表。

在这个过程中，作者需要根据审稿人的意见进行修改，以提高论文的质量。

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Nature中文翻译

自然爱默生走入孤独，远离书斋，如同远离社会一样重要。

纵然无人在我身旁，当我读书或写作时，并非独处一隅。

如果一个人渴望独处，就请他注目于星辰吧。

那从天界下行的光芒,使人们得以出离可触摸的现世.可以这样说，我们假想,大气之所以透明，就是为了让人们看到天国的灿烂光芒.从普通城市的街道向上看，它们是如此深邃伟岸。

假如星辰千年一现,人类关于上帝之城的记忆，必将世代相传，为人们长久地信仰着，珍存着，崇拜着.然而，每一晚,这些美的使者都会降临，以它们无可置疑的微笑,照亮宇宙。

星辰唤醒心中的景仰，即使它们常在，也遥远而不可触摸;而当思想敞开心门,自然景物总会留下熟稔而亲切的印迹. 自然永无恶意可憎的容颜。

如同大智慧者不会因穷尽自然的和谐底蕴而失去对她的好奇之心。

自然之于智慧的心灵绝非玩具。

花朵,动物，群山，它们折射着智者思维的灵光,如同它们娱乐了他纯真的童年。

当我们这样谈论自然时,我们的心灵感觉，清晰独特，诗意盎然.我们在感觉着多面的自然客体和谐完整的映像。

正是这映像区分了伐木工手中的圆木与诗人心中的树木。

今晨我看到那令人愉悦的风景，它们无疑是由二十到三十个农场组成。

米勒拥有这片地,洛克有那片,而曼宁是那片树林的主人。

但是他们都不能占有这片风景。

只有诗人的双眼可以拥有这地平线，这是他们农场中最可贵的，却无人能凭产权而据为己有。

说真话,成年人难得看到自然本身.多数人看不到太阳，至少，他们所见只是浮光略影。

阳光只照亮了成人的双眼所见，却照进儿童的眼睛和心灵深处。

自然的热爱者，内向和外向的感觉尚能和谐的相应,他尚能在成年时保有婴儿的心灵。

与天地的交汇成为必需,就如每日的食物一样。

自然当前时，奔腾的喜悦传便他全身，尽管可能他正身处现实的苦境.他是我的造物，抿灭他无关紧要的悲伤，与我同在他应欢悦，自然向他如是说。

不仅阳光和夏天带来欢跃，四季的每一时分都奉献出愉悦；自然变化的每一时晨无不如是。

从懊热的午后到漆黑的子夜，四季早晚的嬗变对应并验证着人们不同的精神状态。

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Genetic diversity of Chilean and Brazilian Alstroemeria species assessedby AFLP analysisTAE-HO HAN*,MARJO DE JEU,HERMAN VAN ECK&EVERT JACOBSEN Laboratory of Plant Breeding,The Graduate School of Experimental Plant Sciences,Wageningen University,PO Box386,NL-6700AJ Wageningen,The NetherlandsOne to three accessions of22Alstroemeria species,an interspeci®c hybrid(A.aurea´A.inodora), and single accessions of Bomarea salsilla and Leontochir ovallei were evaluated using the AFLP-marker technique to estimate the genetic diversity within the genus Alstroemeria.Three primer combinations generated716markers and discriminated all Alstroemeria species.The dendrogram inferred from the AFLP®ngerprints supported the conjecture of the generic separation of the Chilean and Brazilian Alstroemeria species.The principal co-ordinate plot showed the separate allocation of the A.ligtu group and the allocation of A.aurea,which has a wide range of geographical distribution and genetic variation,in the middle of other Alstroemeria species.The genetic distances,based on AFLP markers,determined the genomic contribution of the parents to the interspeci®c hybrid.Keywords:Alstroemeriaceae,Bomarea,classi®cation,Inca lily,Leontochir,Monocotyledonae.IntroductionThe genus Alstroemeria includes approximately60 described species of rhizomatous,herbaceous plants, with Chile and Brazil as the main centres of diversity (Uphof,1952;Bayer,1987;Aker&Healy,1990).The Chilean and Brazilian Alstroemeria are recognized as representatives of di erent branches of the genus.The family of Alstroemeriaceae,to which Alstroemeria belongs,includes several related genera,such as Bomarea Mirbel,the monotype Leontochir ovallei Phil. and Schickendantzia Pax(Dahlgren&Cli ord,1982; Hutchinson,1973).The species classi®cation in Alstroemeria is based on an evaluation of morphological traits of the¯ower, stem,leaf,fruit and rhizome(Bayer,1987).The avail-able biosystematic information on Alstroemeria species is restricted to the Chilean species,as described in the monograph of Bayer(1987).Little is known about the classi®cation of the Brazilian species(Meerow& Tombolato,1996).Furthermore,morphology-based identi®cation is rather di cult because morphological characteristics can vary considerably in di erent envi-ronmental conditions(Bayer,1987).The immense genetic variation present in the genus Alstroemeria o ers many opportunities for the improve-ment and renewal of cultivars.Therefore,identi®cation of genetic relationships at the species level could be very useful for breeding in supporting the selection of crossing combinations from large sets of parental genotypes,thus broadening the genetic basis of breeding programmes(Frei et al.,1986).The species used in the study reported here are commonly used in the breeding programme of Alstroemeria for cut¯owers and pot plants.Molecular techniques have become increasingly sig-ni®cant for biosystematic studies(Soltis et al.,1992). RAPD markers were used for the identi®cation of genetic relationships between Alstroemeria species and cultivars(Anastassopoulos&Keil,1996;Dubouzet et al.,1997;Picton&Hughes,1997).In recent years a novel PCR-based marker technique,AFLP(Vos et al., 1995),has been developed and used for genetic studies in numerous plants including lettuce(Hill et al.,1996), lentil(Sharma et al.,1996),bean(Tohme et al.,1996), tea(Paul et al.,1997),barley(Schut et al.,1997),and wild potato species(Kardolus et al.,1998).These studies indicated that AFLP is highly applicable for molecular discrimination at the species level.The technique has also been optimized for use in species such as*Correspondence:Tae-Ho Han,Laboratory of Plant Breeding,Wageningen University,PO Box386,NL-6700AJ Wageningen,The Netherlands.Tel.:31317483597;Fax:31317483457;E-mail:tae-ho.han@users.pv.wau.nlHeredity84(2000)564±569Received21June1999,accepted15November1999564Ó2000The Genetical Society of Great Britain.Alstroemeria spp.,which are characterized by a large genome size(2C-value:37±79pg)(Han et al.,1999). In this study,we produced AFLP®ngerprints of 22Alstroemeria species,one interspeci®c hybrid (A.aurea´A.inodora)and the distantly related species Bomarea salsilla and Leontochir ovallei,and we analysed their genetic relationships.The interspeci®c hybrid was included in our study in order to investigate the possibility of identifying the parental genotypes. Materials and methodsPlant materialSeeds and plants of22Alstroemeria species were obtained from botanical gardens and commercial breeders.The collection has been maintained for many years in the greenhouse of Unifarm at the Wageningen Agricultural University.When available,three acces-sions were selected for each Alstroemeria species,and both B.salsilla and L.ovallei were chosen as outgroups. One interspeci®c hybrid(A.aurea´A.inodora)was obtained from earlier research(Buitendijk et al.,1995) (Table1).All accessions were identi®ed according to their morphological traits(Uphof,1952;Bayer,1987).AFLP protocolGenomic DNA was isolated from young leaves of greenhouse-grown plants using the cetyltrimethy-lammonium bromide(CTAB)method according to Rogers&Bendich(1988).The AFLP technique followed the method of Vos et al.(1995)with modi®-cations of selective bases of pre-and®nal ampli®cationsTable1Accessions and origin of Alstroemeria species for AFLP analysisCode Plant material Accession Distribution/altitudeàChilean speciesC1 A.andina Phil.IX-2Chile26°±31°S.L.,2900±3700m(1)C2 A.angustifolia Herb.ssp.angustifolia AN1S,AN2S,AN7K Chile,33°S.L.,<1000m(1)C3 A.aurea Grah.A001,A002,A003Chile,36°±42°/47°S.L.,200±1800m(1) C4 A.diluta Bayer AD2W,AD4K,AD5K Chile,29°±31°S.L.,0±100m(1)C5 A.exserens Meyen AO2S,AO5S,AO7Z Chile,34°±36°S.L.,1500±2100m(1)C6 A.garaventae Bayer AH6Z,AH8K Chile,33°S.L.,2000m(1)C7 A.gayana Phil.XIII-2Chile29°±32°S.L.,0±200m(1)C8 A.haemantha Ruiz and Pav.J091±1.J091±4Chile,33°±35°S.L.,0±1800m(1)C9 A.hookeri Lodd.ssp.c umminghiana AQ5S,AQ6Z,AQ7Z Chile,32°±34°S.L.,0±500m(1)C10 A.hookeri Lodd.ssp.hookeri AP2S,AP3S,AP8K Chile,35°±37°S.L.,0±300m(1)C11 A.ligtu L.ssp.incarnata AJ7S,AJ12K Chile,35°S.L.,1100±1400m(1)C12 A.ligtu L.ssp.ligtu AL4S,AL6K,AL11K Chile,33°±38°S.L.,0±800m(1)C13 A.ligtu L.ssp.s imsii AM6K,AM7K,K101±1Chile,33°±35°S.L.,0±1800m(1)C14 A.magni®ca Herb.ssp.magni®ca Q001±4,Q001±5,Q007Chile,29°±32°S.L.,0±200m(1)C15 A.modesta Phil.AK2W,AK3W Chile29°±31°S.L.,200±1500m(1)C16 A.pallida Grah.AG4Z,AG7K,AG8K Chile33°±34°S.L.,1500±2800m(1)C17A.pelegrina L.AR4S,C057±1,C100±1Chile,32°±33°S.L.,0±50m(1)C18 A.pulchra Sims.ssp.pulchra AB3W,AB7S,AB8S Chile,32°±34°S.L.,0±1000m(1)C19 A.umbellata Meyen AU2Z Chile,33°±34°S.L.,2000±3000m(1) Brazilian speciesB1 A.brasiliensis Sprengel BA1K,BA2K,R001±1,Central Brazil(2)R001±2B2A.inodora Herb.P002,P004±6,P008±3Central and Southern Brazil(2)B3 A.pstittacina(D)Lehm.D031,D032,D92±02±1Northern Brazil(2)B4 A.pstittacina(Z)Lehm.93Z390±2,93Z390±4,Northern Brazil(2)96Z390±6O1Bomarea salsilla Mirbel.M121Central and Southern South America(3) O2Leontochir ovallei Phil.U001Central Chile(4)Interspeci®c hybridF1A1P2±2(A001´P002)-2Buitendijk et al.(1995)Codes from accessions of species maintained at the Laboratory of Plant Breeding,Wageningen University and Research centre.àLiterature source:(1)Bayer,1987;(2)Aker&Healy,1990;(3)Hutchinson1959;(4)Wilkin(1997).EVALUATION OF THE CHILEAN AND BRAZILIAN ALSTROEMERIA SPP.565ÓThe Genetical Society of Great Britain,Heredity,84,564±569.(Han et al.,1999).To assess interspeci®c variation, autoradiograms comprising the AFLP®ngerprints of a mixture of three accessions per species were analysed by pooling5l L of the®nal selective ampli®cation products according to Mhameed et al.(1997).The low level of variation between individual samples showed that pool-ing accessions was justi®ed.Three primer combinations (E+ACCA/M+CATG,E+ACCT/M+CATC and E+AGCC/M+CACC)were selected from a test of96primer combinations,and these produced272, 211and233bands,respectively(Table2).The choice of the primers used in the study was based upon the visual clarity of banding patterns generated and a preferably low®ngerprint complexity.The complexity of the banding pattern is a major limiting factor for scoring AFLP®ngerprints of large-size genomes.Data analysisPositions of unequivocally visible and polymorphic AFLP markers were transformed into a binary matrix, with`1'for the presence,and`0'for the absence of a band at a particular position.The genetic distance(GD) between species was based on pair-wise comparisons and calculated according to the equation:GD xy 1) [2N xy/(N x+N y)],where N x and N y are the numbers of fragments to individuals x and y,respectively,and N xy is the number of fragments shared by both(Nei&Li, 1979).Genetic distances were computed by the software package TREECON(v.1.3b)(Van De Peer&De Wachter, 1993).The dendrogram of the22Alstroemeria species, the interspeci®c hybrid,Bomarea and Leontochir was generated based on the GD matrix by using cluster analysis,the UPGMA(unweighted pair group method using arithmetic averages)method with1000bootstraps (Sneath&Sokal,1973;Felsenstein,1985)(Fig.1). Principal co-ordinate analysis was performed to access interspecies relationships based on the Nei&Li(1979) coe cient[2N xy/(N x+N y)]using the NTSYS-PC pro-gram(Rohlf,1989).Results and discussionThe average genetic distance among species excluding Bomarea,Leontochir,the interspeci®c hybrid and A.umbellata was0.65GD(a table showing the genetic distances between all the species studied is available from the authors on request).Alstroemeria umbellata was excluded because the accessions used were found to be highly related and possibly wrongly classi®ed as di erent from A.pelegrina.The average GD among accessions within a species was0.32GD(data not shown).In addition,the average GD between Brazilian species(GD:0.27)and between Chilean species(GD: 0.33)was not signi®cantly di erent.Buitendijk&Ramanna(1996)suggested that the Chilean and Brazilian species form distinct lineages.The genetic diversi®cation of Alstroemeria species as detected by the AFLP technique revealed three main clusters with99%bootstrap values:the Chilean species,the Brazilian species and the outgroup(Fig.1).This®nding would support an early divergence of these groups and is consistent with the occurrence of interspeci®c cross-ing barriers between the Chilean and Brazilian species (De Jeu&Jacobsen,1995;Lu&Bridgen,1997).The variance of the®rst three principal co-ordinates accounted for34.9%of the total variation,di erentia-ted e ectively among the species and re¯ected the main clustering of the dendrogram.From the principal co-ordinate plot,four groups were clearly demarcated:Table2Sequences of adaptors and primers usedEco RI adaptor5¢-CTCGTAGACTGCGTACC-3¢3¢-CTGACGCATGGTTAA-5¢Mse I adaptor5¢-GACGATGAGTCCTGAG-3¢3¢-TACTCAGGACTCAT-5¢Eco RI+0primer E005¢-GACTGCGTACCAATTC-3¢Eco RI+2primers E+AC5¢-GACTGCGTACCAATTCAC-3¢E+AG5¢-GACTGCGTACCAATTCAG-3¢Eco RI+4primers E+ACCA5¢-GACTGCGTACCAATTCACCA-3¢E+ACCT5¢-GACTGCGTACCAATTCACCT-3¢E+AGCC5¢-GACTGCGTACCAATTCAGCC-3¢Mse I+0primer M005¢-GATGAGTCCTGAGTAA-3¢Mse I+2primers M+CA5¢-GATGAGTCCTGAGTAACA-3¢M+CT5¢-GATGAGTCCTGAGTAACT-3¢Mse I+4primers M+CACC5¢-GATGAGTCCTGAGTAACACC-3¢M+CTAC5¢-GATGAGTCCTGAGTAACTAC-3¢M+CTAG5¢-GATGAGTCCTGAGTAACTAG-3¢566T.-H.HAN ET AL.ÓThe Genetical Society of Great Britain,Heredity,84,564±569.(i)the Brazilian group;(ii)the Chilean group;(iii)the A.ligtu group;and (iv)the outgroup (Fig.2).The Brazilian species (A.brasiliensis , A.psittacina and A.inodora )were consistently assigned to one cluster with 98%bootstrap values,whereas the Chilean species were rather weakly clustered with 62%bootstrap values containing several subgroups within the Chilean group (Figs 1and 2).The dispersion of the Chilean species on the principal co-ordinate plot re¯ected a wider geneticvariation than the Brazilian species.However,the narrow variation of the Brazilian species might be caused by the limited number of species investigated.Buitendijk &Ramanna (1996)described the similar-ities between C-banding patterns of A.inodora and A.psittacina ;in our study these species clustered strongly,reinforcing this ®nding (Fig.1).The similarity between A.psittacina and A.inodora was also revealed by allozyme analysis (Meerow &Tombolato,1996)and by a study using species-speci®c repetitive probes (De Jeu et al.,1995).These ®ndings are also supported by the fact that A.inodora and A.psittacina are easily crossed (De Jeu &Jacobsen,1995).In addition,the Chilean species A.aurea was posi-tioned between three subgroups (Fig.2).The unique position of A.aurea ,and the observation that this species has a wide geographical spread,suggest that other Chilean species may have evolved from A.aurea ecotypes.Alstroemeria aurea is indeed a widespread inhabitant in the regions with higher rainfall at the more southern latitudes between 33and 47°S in Chile (Bayer,1987;Buitendijk &Ramanna,1996).It is not found in Brazil,although A.aurea plants are found on both sides of the Andes mountains in Argentina,supporting the possibility that A.aurea ecotypes were also the ancestors of the Brazilian species (A.F.C.Tombolato,personal communication).Alstroemeria pelegrina and A.umbellata were assigned as sister species with a GD of 0.26showing a remarkable genetic similarity (data available on request).The species we coded under the name A.umbellata actually seemed to be an A.pelegrina species that did not ¯ower for many years.Alstroemeria haemantha was assigned to a group together with A.ligtu ssp.ligtu ,A.ligtussp.Fig.1Dendrogram of 22Alstroemeria species,Bomarea salsilla and Leontochir ovallei resulting from a UPGMA cluster analysis based on Nei's genetic distances obtained from 716AFLP bands.The bootstrap analysis was conducted using TREECON (v.1.3b)with 1000bootstrap subsamples of the data matrix.Percent-age values for those branches occurring in at least 60%of the bootstrap topologies areshown.Fig.2Relationships among 22Alstroemeria species,the F 1hybrid,Bomarea salsilla and Leontochir ovallei by principal co-ordinate analysis using Nei and Li coe cients.The three principal co-ordinates accounted for 34.9%of the totalvariation.PC1,PC2and PC3:®rst,second and third principal co-ordinates.See Table 1for species names.EVALUATION OF THE CHILEAN AND BRAZILIAN ALSTROEMERIA SPP.567ÓThe Genetical Society of Great Britain,Heredity ,84,564±569.incarnata and A.ligtu ssp.simsii(Figs1and2)(Aker& Healy,1990;Ishikawa et al.,1997).Bayer(1987) suggested the synonymous name of A.ligtu ssp.ligtu for A.haemantha Ruiz and Pavon.Our results support this hypothesis.Alstroemeria exserens was positioned between the Chilean group and the A.ligtu group (Fig.2).Alstroemeria andina and A.angustifolia ssp. angustifolia,and A.hookeri ssp.cumminghiana and A.hookeri ssp.hookeri were clustered together with 95%and93%bootstrap values,respectively.The interspeci®c hybrid(A1P2±2)was included in our study in order to investigate the possibility of the identi®cation of the parental genotypes.The F1hybrid A1P2±2showed a0.45-GD value with A.inodora and 0.59GD value with A.aurea showing genomic contri-bution of both parents(data available on request).It indicated the feasibility of the AFLP technique as a tool for the identi®cation of parental genotypes (Sharma et al.,1996;Marsan et al.,1998).Bomarea and Leontochir showed the mean GD value of0.83as the outgroup,thus showing large genetic distances within the Alstroemeriaceae family.In conclusion,the genetic variation and the genetic relationships among Alstroemeria species were e ciently rationalized by using AFLP markers for the character-ization of germplasm resources.In general,the topolo-gies of the dendrogram and the principal co-ordinate analysis of our study were in agreement with Bayer's views(Bayer,1987)on the classi®cation of the Als-troemeria species.Furthermore,this technique might be useful for the identi®cation of parental genotypes in interspeci®c hybrids.AcknowledgementThe authors would like to thank Anja G.J.Kuipers and Jaap B.Buntjer for critical reading of the manuscript and for 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