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C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | conclusions12,41,42. 中文
Why would the long-term burial rate of organic carbon have decreased over the past 40 Myr? Most organic carbon burial today takes place in shallow marine environments such as estuaries, continental shelves and deltas. In these well oxygenated environments, the burial rate of organic carbon is a ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | ~350 μmol kg–1. If high-latitude sea surface temperatures were ~10 °C warmer in the mid-Cenozoic, a level consistent with planktonic isotopes14,73, then O2 concentrations would have been only ~275 μmol kg–1. The inferred increase through time in ocean oxygen concentrations could have resulted in decreased organic carbo... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | that initiated the change, a problem which may not be critical in the case discussed here; namely, gradually more intense forcing as the Tibetan plateau increases in elevation. 中文
Two other processes have been proposed as negative feedbacks to atmospheric CO2 decreases driven by enhanced silicate weathering. One is pre... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Given the suggestions above, it is certainly possible, if not probable, that increases in silicate weathering rates could be sustained for millions to tens of millions of years without an increase in mantle degassing rates. In particular, the assumption that rates of volcanism and silicate weathering need to be balance... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Tibetan uplift as a possible cause of climate change. Their basic disagreement is with the inference of accelerating late-Cenozoic uplift throughout the world. 中文
It is consistent with both hypotheses to argue that uplift of Tibet (and possibly elsewhere) is a plausible first cause of Cenozoic climate changes (through ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | We propose that over the past 40 Myr, uplift of the Tibetan plateau has resulted in stronger deflections of the atmospheric jet stream, more intense monsoonal circulation, increased rainfall on the front slopes of Himalayas, greater rates of chemical weathering and, ultimately, lower atmospheric CO2 concentrations. The... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Ruddiman, W. F. & Raymo, M. E. The Past Three Million Years: Evolution of Climatic Variability in the North Atlantic Region (eds Shackleton, N. J., West, R. G. & Bowen, D. Q.) 227-234 (Cambridge Univ. Press, Cambridge, 1988).
Ruddiman, W. F. & Kutzbach, J. E. J. Geophys. Res. 94, 18409-18427 (1989).
Raymo, M. E., Ruddi... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Crowley, T. J., Mengel, J. G. & Short, D. A. Nature 329, 803-807 (1987).
Barron, E. J. Palaegeogr. Palaeoclimatol. Palaeoecol. 50, 45-61 (1985).
Kennett, J. P. J. Geophys. Res. 82, 3843-3860 (1977); Mesozoic and Cenozoic Oceans (ed. Hsu, K. J.) 119-122 (Am. geophys. Un., Washington DC, 1986).
Barker, P. F. & Burrell, J... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Stallard, R. F. & Edmond, J. M. J. Geophys. Res. 88, 9671-9688 (1983); Stallard, R. F. Physical and Chemical Weathering in Geochemical Cycles (eds Lerman, A. & Meybeck, M.) 225-246 (Kluwer, Dordrecht, Holland, 1988).
Manabe, S. & Terpstra, T. B. J. Atmos. Sci. 31, 3-42 (1974).
Hahn, D. G. & Manabe, S. J. Atmos. Sci. 32... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Emerson, S. The Carbon Cycle and Atmospheric CO2: Natural Variations Archean to Present (eds Sundquist, E. T. & Broecker, W. S.) 78-87 (Am. geophys. Un., Washington DC, 1985).
Pedersen, T. F. & Calvert, S. E. Am. Assoc. Petrol. Geol. Bull. 74, 454-466 (1990).
Betts, J. N. & Holland, H. D. Palaeogeogr. Palaeoclimatol. P... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 由于蒸发–降水过程会使大陆冰盖优先富集质量较轻的同位素16O,因此,冰期时海水中18O/16O的比值会明显增大。方解石与水中18O/16O的分馏受温度的影响,也向同一方向变化(温度降低导致18O/16O比值增大)。因此,深海沉积物岩芯中得到的海洋生物CaCO3壳体的同位素记录了过去冰储量与海洋温度的相关信息。 英文
近5,500万年来的氧同位素数据(参考文献14、15)显示,δ18O值整体表现为长期升高,中间被几次相对较快的变化打断(图1)。渐新世早期(距今约3,600万年)同位素比值的急剧增大可能反映了南极洲第一次较大的冰增长事件[16],随之而来的是持续约2,000万年的气候变冷。中新世中期和上新世晚期δ18O值进一步增大,分别... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 英文
青藏高原平均海拔近5千米,面积为美国的一半,是地球表面最为壮观的地形地貌。它由印度-大洋洲板块与亚洲板块相撞形成。上述板块之间的刚性碰撞很可能开始于始新世中期(4,400万年至5,200万年前;参考文献33~35)并一直持续到现在。对于青藏高原的海拔变化史我们知之甚少。事实上,我们仅有两个已经确定的数据点:现在的海拔,以及白垩系到下始新统之间海相灰岩的出现,后者说明7千万年至1亿年前青藏高原的大部分仍位于海平面以下,其中有些地区直到5,200万年前仍位于水下(参考文献33~35)。虽然我们知道高原从“a”点上升到了“b”点,但可以这么说,要理解板块的构造运动和地球物理过程[33-35],还必须要对其隆升史有更为详细的了解,这样... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 在BLAG的模型中,大气中CO2浓度与全球温度最明显的降低时间出现在1亿年至5,000万年前(始新世之前),主要是由全球海底扩张速率降低所致,海底扩张速率控制着地幔的排气作用,并间接影响海平面高度。但地质学证据显示,更大规模的气候变冷主要发生于5,000万年前至今的时期(始新世以后)。 英文
侵蚀驱动的CO2模型[3,4,23]提供了造成这种不匹配的一个可能的解释。雷莫等[3]根据现代河流的研究结果[44,45]提出,化学侵蚀引起的长期大气CO2消耗速率是大陆地势高低而非面积的函数,而大气温度对全球化学侵蚀速率的影响则相对较弱。其原理如下:现今许多地表以极低的和深度风化的地盾为主要特征,这些特征对全球河流溶解物通量几乎没有贡献。即使... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 近3,000万年至4,000万年来海底的扩张速率似乎变化不大(参考文献56),因此人们普遍认可,只有陆源放射性锶输送量的明显增加才能解释晚新生代海洋中87Sr/86Sr比值的显著升高。而陆源放射性锶的增加可能是由全球化学风化速率[3,6,9,12]增加和(或)河流中平均锶同位素组成[8-10]的升高造成的。 英文
图2.a,基于海相碳酸盐分析得出的过去7,000万年中海水锶同位素组成(来自参考文献9)。b,新生代全岩碳酸盐的δ13C(来自参考文献61)。δ13C=[(13C/12C)样品/(13C/12C)标准-1],PDB标准。 英文
鉴于硅酸盐风化作用与高87Sr/86Sr比值之间存在关联,在硅酸盐风化速率不变的前提下,只有... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 英文
最全面的新生代全岩碳酸盐δ13C值综合图(图2b;参考文献61)正显示了这一减少情况。沙克尔顿[61]利用上述数据估算出,新近纪以来以有机质而非碳酸盐形式埋藏的那部分碳所占的比例从20%降到了10%,导致大气中CO2净增加(另外,这些数据与油母岩风化作用相对于有机碳埋藏作用的增强是相符的,这种增强也会导致大气CO2净增加)。有机碳子循环这种变化的大小和方向恰好可以阻止构造运动引起的硅酸盐风化作用持续增强(约40%),使大气中的CO2不至于完全耗尽。估算结果取决于光合分馏系数如何变化、何时定义“稳态”(或现今的长期平均值)等假设,以及采用何种碳同位素数据集。采用不同假设和不同数据库的类似研究得到的结果相对更保守一些[12,41,... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 但是,随着大气中CO2的减少,海洋pH值和OH–浓度上升,形成不利于CO2移除的条件,再次为快速“冰室效应”提供了负反馈机制。 英文
鉴于上述论点,即使地幔脱气速率不升高,硅酸盐风化作用速率增加也完全有可能(如果不是很有可能的话)维持成百上千万年的时间。特别是,关于火山作用与硅酸盐风化作用速率达到平衡的时间要长于百万年[10]的假定可能没有必要。最后一种可能性是,海底扩张速率并非地幔脱气速率的良好替代指标。卡尔代拉[13]提出,自侏罗纪以来,远洋碳酸盐的俯冲量不断增加,已导致来自地幔的变质CO2通量增加,而这正是推断出的晚新生代高速化学侵蚀的原因所在。当海底扩张速率恒定不变时,这可以提供维持高速硅酸盐风化作用所需的“额外”CO2。 ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 英文
(齐红艳 翻译;李吉均 审稿)
Curling and Closure of Graphitic Networks under Electron-Beam Irradiation
D. Ugarte
Editor’s Note
After the discovery of cage-like carbon molecules called fullerenes and tubular structures called carbon nanotubes, it was suspected that sheets of graphite-like carbon might adopt a range of nanoscale ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | THE remarkable stability of the C60 molecule has been attributed to its highly symmetrical structure where the carbon atoms are arranged at the vertices of a truncated icosahedron1. The C60 molecule may be viewed as a hexagonal graphitic sheet which, by incorporating pentagons, has eliminated all dangling bonds, curlin... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | tubules14. 中文
Under the conditions of observation in an electron microscope, strong irradiation in some respects resembles a high-temperature regime, allowing structural fluidity; for example, amorphous carbon films usually develop slight graphitization under the electron beam. In particular, irradiation usually heats ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | cages (see Fig. 2), the distance between layers agreeing with that for bulk graphite (d002 = 3.34 Å). The apparent disorder in the spherical shells arises as a consequence of the low electron dose necessary for taking the micrographs; under such conditions, the heating effect of the electron beam is insufficient to per... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | curved structures. Hence, they support the dangling bond minimization scheme, proposed to explain the growth of fullerenes from carbon vapour9. 中文
Fig. 2. Detailed structure of the graphitic particles marked with an arrow in Fig. 1c. Dark contrast rings correspond roughly to atomic positions, and the distance between ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | The sequence shown in Fig. 1 clearly reveals that if enough energy is provided, spherical structures are favoured over tubular ones. This observation agrees with the predictions made for giant fullerenes18,19 (monolayers), but van der Waals interaction between the concentric layers should be included in order to compar... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | This notion also raises a point concerning the solid allotropes of carbon. When Krätschmer et al.2 synthesized large amounts of the C60 molecule for the first time, they prepared a new, third form, of solid carbon (called fullerite), which is a three-dimensional packing of C60 spheres and is distinct from the two tradi... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Ebbesen, T. W. & Ajayan, P. M. Nature 358, 220-222 (1992).
Curl, R. F. & Smalley, R. E. Scient. Am. 265, 32-41 (October, 1991).
Iijima, S. J. Cryst. Growth 50, 657-683 (1980).
Iijima, S. J. Phys. Chem. 91, 3466-3467 (1987).
Adams, G. B., Sankey, O. F., Page, J. B., O’Keeffe, M. & Drabold, D. A. Science 256, 1792-1795 (... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 英文
我们在一台300 kV HREM显微镜(飞利浦EM430 ST)中照射炭黑,使用的电子束剂量超过正常操作条件下的10~20倍(通常剂量为10~20 A·cm–2)。图1显示了一组经照射的石墨颗粒的图像序列,拍摄间隔为10分钟。初始炭黑是从电弧放电装置中收集到的,其中主要包含由共轴石墨管形成的纳米尺寸针状物,以及由小的平面型石墨薄片接合而形成的一些多面体石墨颗粒(图1a)。所有颗粒上都覆盖着一层薄的无定形碳。在图像序列的中间部分(图1b)里,颗粒呈现出更为明显的曲率,特别是,微管型结构正在瓦解。在这个阶段中,无定形碳层石墨化并外延到颗粒上。最后(图1c),电子退火产生出一种几乎完全由球状颗粒组成的样品。对颗粒的详细检测表明,它们... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 当克雷奇默等人[2]第一次合成大量C60分子时,他们制备出了一种新型——第三种形式——的固态碳(称为富勒烯),它是C60球体的三维堆积,有别于两种传统晶体形式的碳:石墨和金刚石。考虑到我们观测到的石墨形成多壳层球体(“洋葱”)的趋势——单壳层富勒烯只是第一位成员而已,我们猜测富勒烯固体是一族新的固态碳物质的第一位成员,这族固态碳物质可以通过范德华相互作用由这些洋葱状石墨球体堆积形成。要制备和分离多壳层石墨球体还需要进一步的实验研究,但是一大族碳材料正等待着实验科学家技能的发掘。 英文
(王耀杨 翻译;顾镇南 审稿)
Ordered Mesoporous Molecular Sieves Synthesized by a Liqui... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | the precursor material. Here we report the synthesis of mesoporous solids from the calcination of aluminosilicate gels in the presence of surfactants. The material14,15 possesses regular arrays of uniform channels, the dimensions of which can be tailored (in the range 16 Å to 100 Å or more) through the choice of surfac... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Transmission electron microscopy (Fig. 1a) shows the regular hexagonal array of uniform channels characteristic of MCM-41. A representative electron diffraction pattern (Fig. 1b), with the MCM-41 in the same orientation, confirms the periodicity of the structure. For the sample described above, an interplanar spacing d... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Fig. 2. a, Representative X-ray diffraction pattern of MCM-41. The pattern was obtained from a Scintag PAD automated diffraction system using Θ–Θ geometry, Cu Kα radiation (λ = 1.5418 Å) and an energy-dispersive detector. b, Representative X-ray diffraction pattern of cubic (Ia3d) phase. Inset is expansion of region 2Θ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | altering the pore diameter of MCM-41 is to add auxiliary hydrocarbons, such as alkylated benzene (for example 1,3,5-trimethylbenzene), to the synthesis mixture16. The incremental addition of 1,3,5-trimethylbenzene results in the concomitant increase of d100 and the pore diameter. Hexagonal phases with pore diameters up... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | These similarities suggest that these mesoporous molecular sieves are formed by a “liquid-crystal templating” mechanism. In this mechanism (Fig. 5), inorganic material occupies the continuous solvent (water) region to create inorganic walls between the surfactant cylinders. It may be that encapsulation occurs because a... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Additional strong evidence for the proposed liquid-crystal templating mechanism is the discovery of another member of this family14,15 that mimics a liquid-crystal structure25. A representative powder X-ray diffraction pattern of a silicate molecular sieve with cubic symmetry (Ia3d) is given in Fig. 2. The cubic phase ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Beck, J. S. U.S. Patent No. 5,057,296 (1991).
Ekwall, P. Advances in Liquid Crystals, Vol. 1 (ed. Brown, G. H.) (Academic, New York, 1971).
Ekwall, P., Mandell, L. & Fontell, K. Liquid Crystals (ed. Brown, G. H.) 325-334 (Gordon and Breach, London, 1969).
Luzzati, V. Biological Membranes (ed. Chapman, D.) 71-123 (Acade... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 典型的微孔材料是诸如沸石[2]的具有晶体骨架的固体,迄今已观察到某些金属磷酸盐的孔径约为10~12 Å[3-5],黄磷铁矿的孔径约为14 Å[6],这些是目前在微孔材料中发现的最大孔径。介孔固体包括氧化硅基材料[7]和改性层状材料[8-11]等,但它们都是无定形或者次晶态的,孔的排列不规则且尺寸分布较宽[8,12]。虽然孔的尺寸可以通过将表面活性物质插入层状硅酸盐来加以调控[9,13],但是最终产物仍然部分保留了原材料的层状性质。本文我们要报道的是,在有表面活性剂的条件下通过煅烧铝硅酸盐凝胶来合成介孔固体材料。所得材料[14,15]具有均匀孔道的规则排列结构,该孔道尺寸可以通过选取表面活性剂、辅助化学试剂和反应条件来进行调节(范围从... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 我们没有检测到任何l≠0的X射线衍射峰。这可能是由于材料中大的规则孔道使得hk0衍射占主要地位,从而导致沿c轴的散射强度显得非常弱。 英文
改变合成过程中所用阳离子表面活性剂的烷基链长度可以改变MCM–41的孔径大小。例如,用十二烷基三甲基铵离子(C12H25(CH3)3N+)来代替十六烷基三甲基铵离子,我们制备出一种孔径为30 Å的MCM–41样品。所合成的基于C12的MCM–41中,C/N摩尔比为15,这与未反应时的表面活性剂是一致的。另一种改变MCM–41孔径的方法是向合成混合物中添加辅助性的碳氢化合物,比如烷基苯(例如1,3,5–三甲基苯)[16]。1,3,5–三甲基苯添加量的增多使得d100和孔径随之相应增大。孔径高达约1... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Studies of sediments in the North Atlantic Ocean had revealed layers of minerals thought to have been carried by icebergs and deposited when the ice melted. These “Heinrich layers”, formed during the last ice age, were a mystery. Here oceanographer Gerard Bond and colleagues show that the deposits can be used to track ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | THE most detailed study of the sediment composing the Heinrich deposits has been made on cores from DSDP site 6092 (Fig. 1). High percentages of ice-rafted detritus (IRD) and low concentrations of foraminifera clearly define the six deposits that formed during the last glacial period (Fig. 2). Foraminiferal stratigraph... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | dolomite in eastern Canada and northwestern Greenland are evidence that the carbonate-bearing icebergs originated in the Labrador Sea and Scotian Shelf regions. Their transit completely across the Atlantic was made possible by extreme cooling of surface waters, as indicated by the high percentages of the polar plankton... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | DSDP site 609 material, detrital carbonate constitutes 40% to 60% of the <63 μm fraction. The detrital carbonate grains are rounded to subrounded and have fine-grained recrystallized textures. At one locality in the Dreizack area, core 244, oolites and fragments of echinoderms have been identified in the carbonate IRD.... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | higher densities than ambient sediment and they lack foraminifera, the IRD flux values for those layers are a minimum. The decrease in foraminifera flux in the H layers is too large to be an artefact of variations in density and porosity of typical glacial sediment17. 中文
Table 3. Thicknesses of detrital carbonate-rich... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | (Fig. 1; Table 3). In the southwest, all six Heinrich deposits contain a layer with abundant detrital carbonate. To the north and east, however, H3 and H6 lack these layers, and their IRD resembles that of the ambient sediment. Still farther to the north and in the southernmost samples, none of the Heinrich deposits id... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | deep southward penetration of polar water. In DSDP site 609, the flux of planktonic foraminifera of size >150 μm dropped markedly during formation of at least the first three deposits (Table 2). This implies a reduction in the number of foraminifera living in the surface water, although we note that dissolution of fora... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | large amounts of glacier ice, much of it carbonate-bearing, into the Labrador Sea and perhaps into the Scotian shelf as well. Cold sea surface temperatures slowed melting and the icebergs drifted into the North Atlantic. Rapid transit of huge amounts of this ice eastward along the southern edge of the polar gyre led to... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Perhaps the most important result of our study is its evidence of repeated, rapid advances of ice sheets in eastern North America and the questions it raises about the cause of those events. One explanation is stochastic surging2, but that does not account for evidence of extreme cooling of surface water and reduced fl... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | † Bundesamt für Seeschiffahrt und Hydrographie, Postfach 30 12 20, 2000 Hamburg 36, Germany
‡ C.F.R. Laboratoire mixte CNRS-CEA, Domaine du CNRS, 91198, Gif-sur-Yvette Cedex, France
§ Institute of Arctic and Alpine Research and Geological Sciences Box 450, University of Colorado, Boulder, Colorado 80309 USA
‖ Départeme... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Birgisdóttir, L. Ber. Sonderforschungsber. 313 (34), 112 (1991).
Broecker, W. S. et al. Paleoceanography 3, 1-19 (1988).
Ruddiman, W. F. et al. Init. Rep. DSDP 94, 247-349 (U.S. Govt Printing Office, Washington, DC, 1987).
Ruddiman, W. F. & McIntyre, A. Palaeogeogr. Palaeoclimatol. Palaeoecol. 35, 145-214 (1981).
Ruddi... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 本文我们将证明,距今最近的沉积于14,000~70,000年前的六个“海因里希层”记录了海表温度和盐度显著下降、沉积物中浮游有孔虫通量减少以及发源于加拿大东部大量冰山的短暂排入。由冰筏碎屑碳酸盐所清楚标志的冰山运移路径可追踪到3,000 km以上——这是一段相当远的距离,证明了表层水体的急剧变冷和大量浮冰的存在。上述极端事件的成因令人迷惑不解,它们可能反映了劳伦泰德冰盖由于气温降低造成的多次快速前进过程,不过来自格陵兰岛冰芯的温度记录却仅显示出微弱的对应信号。而且,这些事件的间隔为5,000~10,000年,与米兰科维奇轨道周期不相符,由此引出一个问题:导致变冷事件的最终起因是什么? 英文
关于海因里希沉积物组成的最详细研究是基于... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 英文
表1.DSDP 609、HU75-55、V23-81和V23-16站的AMS放射性碳定年结果
* 对假定的表层水体中的碳与大气中的碳相差400年进行校正。G.b.表示分析对象为泡抱球虫,G.i.表示分析对象为G. inflata(有孔虫的一种)。其他测定结果均根据厚壁新方球虫得到(I.c.),H1等层是根据低有孔虫密集度确定出的海因里希沉积层(示例见图2)。Hc指的是海因里希沉积物中富含碎屑碳酸盐的冰筏碎屑层。
† 据参考文献29;
‡ 在苏黎世为本文所做的分析结果;
§ 据参考文献19。 英文
表2.DSDP 609站深海岩芯的有孔虫和冰筏碎屑通量估计
通量估计是通过对已测定的样品干重、颗粒和有孔虫计数、放射性碳年龄间... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 在DSDP 609站中,直径大于150 μm的浮游有孔虫通量在至少最上部三个沉积层形成时期明显减少(表2)。这表明生活在表层水体中的有孔虫数量已经减少,尽管我们注意到在H3中有孔虫已经开始发生分解。表层水体中有孔虫数量的减少可能与初级生产力的变化有关,但也可能反映了表层水体的其他变化,即与温度或盐度有直接关系。六个海因里希沉积层中浮游有孔虫的δ18O值均显著降低(图2)。由于浮游有孔虫组合指示寒冷环境,因此,当每一个“海因里希层”沉积时海表盐度必定显著降低。 英文
根据目前已有的证据,我们可以对海因里希层及其异常矿物学特征做出一个尝试性的解释。首先,我们注意到,海因里希沉积中出现富含碎屑碳酸盐的层位,但并未扩展到整个沉积层(图2),... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Although rising concentrations of greenhouse gases such as carbon dioxide are generally expected to increase global temperatures, climate models exploring this scenario did not seem to give temperatures trends that matched with observations. This led some to propose that the observed warming had other origins, perhaps ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | WE use an upwelling-diffusion energy-balance climate model4,5 to simulate the effects of greenhouse and solar forcing over the period 1765 to 1985. In a series of analyses, we vary the climate sensitivity and a scaling factor linking changes in solar cycle length to radiative forcing, and determine the best fit between... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Fig. 1. The two solar cycle length records. Solid line: record derived in this paper (KW). Dashed line: record derived by Friis-Christensen and Lassen8 (FCL). KW is derived from the same basic sunspot data set as FCL but the raw maximum-to-maximum and minimum-to-minimum length series were combined into a single series ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | We consider first greenhouse forcing alone (Table 1). For history 1, the best fit occurs when ΔT2× = 1.5 °C, with 50.9% of the variance in the observed temperature record accounted for. For history 2, the best fit occurs at a higher climate sensitivity, ΔT2× = 3.7 °C, as the global forcing is not as great. This simulat... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Fig. 2. Comparison of modelled (thick) and observed (thin) global-mean surface air temperature changes as departures from the 1861–1900 mean. (See Table 1 for associated CO2-doubling temperatures and solar forcing scaling factors.) We use global-mean (land-plus-marine) temperature10 as it is the best available indicato... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | experiment with solar forcing alone must be considered low, as it is illogical to neglect greenhouse forcing given the well-established case for its existence1,2. 中文
We now assess the plausibility of the greenhouse-plus-solar simulations in terms of their implied climate sensitivities and solar forcing ranges. The best... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | changes before 1900, but there is no evidence available at present to support a more complex relationship than assumed here. 中文
In summary, our results provide circumstantial support for the hypothesized link between solar cycle length and irradiance. Even in the optimal cases considered here, however, the solar contri... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 13). In addition, the model formulation and parameter values used13 differ slightly between the two analyses. 中文
(360, 328-330; 1992)
P. M. Kelly and T. M. L. Wigley
Climatic Research Unit, University of East Anglia, Norwich NR4 7TJ, UK
Received 7 July; accepted 19 October 1992.
References:
Houghton, J. T., Jenkins, ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Jones, P. D., Wigley, T. M. L. & Farmer, G. in Greenhouse-Gas-Induced Climatic Change: A Critical Appraisal of Simulations and Observations (ed. Schlesinger, M. E.) 153-172 (Elsevier, 1991).
Acknowledgements. This analysis was supported by the US Department of Energy, Atmospheric and Climate Research Division.
太阳活动周期... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 其他机制也会起到一定作用[2-5],它们的加入可显著改变对最佳拟合气候敏感度的估计,并会导致解释方差值的进一步增加(例如,气候的内变率[3-5]就为单纯考虑温室强迫的模拟结果与实测变暖趋势间的差异提供了另一种解释)。其次,分析中使用的观测数据和气候模式中的一些参数存在不确定性,尽管这些数据记录得很完善[1]。这些问题不太可能会影响温室效应与太阳辐射贡献量的相对水平,但却会对其绝对水平有很大影响。 英文
首先,我们仅考虑温室强迫(表1)。对于历史记录1,当ΔT2×=1.5°C时达到最佳拟合,此时温室强迫在实测温度记录中的解释方差为50.9%。在历史记录2中,最佳拟合出现在较高的气候敏感度上,ΔT2×=3.7°C,而全球强迫则并没有这么... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 例如,1795~1834年间太阳辐射强迫升高了2.5 W·m–2,意味着辐照度升高了超过1%。这么大的变化量是不太可能的,它远远超出了形成小冰期[15]必要的偏差,更为重要的是,它甚至超出了根据天文数据估计出的可能偏差范围[16]。在其他两种情况中(历史记录2,KW记录;历史记录1,FCL记录),1800年前后的辐照度变化与上文提到的独立证据也不一致。只有在历史记录2和FCL记录的情况下,所得到的辐照度变化与上文证据一致。在此个例中,1765~1804年的40年间太阳辐照度的最大变化量为–0.5 W·m–2(–0.21%)。除此以外,ΔQs和ΔL之间的非线性关系有可能缩小1900年之前太阳辐射强度的变化范围,但目前还没有能够支持两者... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Following earlier studies1-6, attention has recently been directed again to the possibility that long-term solar irradiance variations, rather than increased greenhouse gas concentrations, have been the dominant cause of the observed rise in global-mean surface temperature from the mid-nineteenth century to the present... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | is small, as simple climate models reproduce the response of more-complex climate models15,16 and these show similar responses to CO2 and solar-constant changes17. For convenience we write λ = ∆F2×/∆T2×, where ∆T2× is a prescribed equilibrium value of ∆Ta resulting from a radiative forcing equivalent to that for doubli... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | a rough estimate of ∆FSO4 for the cloudy atmosphere10. 中文
We estimate ∆T2× for three cases: (1) GHG without and with ASA; (2) Sun without and with ASA; and (3) GHG + Sun without and with ASA. Case (2) cannot occur by itself, however, because, for any climate sensitivity λ, the radiative forcing due to the observed incr... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Figure 1 presents plots of ∆T2×, β, the unexplained standard deviation (USD: standard deviation of δT0(t) – δTm(t) as a percentage of the standard deviation of δT0(t)), and the residual linear trend (RLT: trend of δT0(t) – δTm(t)) against ∆FSO4(1978). For ∆FSO4(1978) = 0, Fig. 1 shows that adding solar forcing with β =... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | ∆FSO4(1978) = –0.3 W m–2 (Fig. 2B) oscillate about δTPI = –0.13 °C, with maxima in the eighteenth, nineteenth and twentieth centuries. For Sun alone, the eighteenth- and twentieth-century maxima are comparable, whereas for Sun plus ASA the eighteenth-century maximum is larger. For GHG plus Sun (Fig. 2C), δTm oscillates... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Fig. 3. Contributions of GHGs, intercycle solar variations and ASAs to global warming, ΔTm. The heavy line for the total ΔTm(“Total”) is not shown before 1801 in a and 1785 in b so that solar contribution (Sun) can be seen. 中文
Figure 4 presents the intercycle solar-irradiance anomaly, ∆S = ∆FSun[4/(1–αp)], with αp = 0... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | It can be argued that past intercycle solar-irradiance variations may have been larger than those used herein based on estimating β to minimize the RMSE between δTm and δT0. Although it is likely that significantly larger irradiance variations would have been detected by past ground-based observations30, conclusive evi... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Schlesinger, M. E., Jiang, X. & Charlson, R. J. in Climate Change and Energy Policy. Proc. int. Conf. Global Climate Change: Its Mitigation Through Improved Production and Use of Energy (eds Rosen, L. & Glasser, R.) 75-108 (American Institute of Physics, New York, 1992).
Houghton, J. T., Jenkins, G. J. & Ephraums, J. J... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Baliunas, S. & Jastrow, R. Nature 348, 520-523 (1990).
Lockwood, G. W. et al. Nature (in the press).
Fröhlich, C. in The Solar Output and its Variation (ed. White, O. R.) 93-109 (Colorado Associated Univ. Press, Boulder, 1977).
Penner, J. E., Dickinson, R. E. & O’Neill, C. A. Science 256, 1432-1433 (1992).
Kelly, P. M.... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | ∆F2×是根据辐射传输模式对标准的及2倍的CO2浓度计算得到的(比如ICRCCM[19]),这种计算不包括任何太阳辐射变化的影响。 英文
模式是由随时间变化的对流层顶辐射变化所驱动的,而辐射变化是由于温室气体(GHGs)增加、太阳辐照度周期间变化和不断增加的人类活动产生的硫酸盐气溶胶(ASAs)引起的。温室气体的强迫表示为:
其中,C(t)是由IPCC/90给出的从1765年到1990年这一时段年平均等效CO2浓度(参考文献18)。太阳辐照度周期间变化的强迫表示为:∆FSun(t)=β[P0–P(t)], 这里,P(t)是“11年”太阳黑子周期的长度,由格莱斯贝格[20]根据1638年6月到1744年12月的资料以及弗里斯-克里斯... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 形成巨大反差的是在仅有太阳辐射强迫的情况下减小ΔFSO4(1978),可以使ΔT2×向0逼近,而β迅速增加,以至于USD和RLT在ΔFSO4(1978)≤ –0.4 W·m–2时增加到定值。GHG强迫加太阳辐射强迫情况下的ΔT2×与仅有GHG强迫情况下的ΔT2×的比值在ΔFSO4(1978)=0时为0.52,并随着ΔFSO4(1978)的减小而降低。 英文
图2展示了模拟的温度异常值δTm与观测到的图1中a点到f点的温度异常值δT0的比较。在a、c和e点人类排放的硫酸盐气溶胶强迫为0,在b和f点,ΔFSO4(1978)=–1.1 W·m–2,是前面提及的不确定性分析[10]的中间估计值,而d点是只有太阳辐射强迫情况下当ΔFSO4接近... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 这个周期间的变化在0.1%~3%之间,该范围由洛克伍德等[29]通过对25颗太阳型恒星的观测所发现。因此,我们的结果(尽管是间接的)提供了强有力的证据,证明太阳辐照度是变化的,这种变化对1856年以来观测到的温度变化是有贡献的。 英文
图4.图3中两种情况下太阳辐照度的周期间变化∆S (a)和∆S/S (b),这里S0 = 1,367.5 W·m–2,是1980年到1989年间太阳峰年卫星(SMS)所测量的太阳平均辐照度。图中也显示了太阳峰年卫星观测值的标准偏差±σ、±2σ以及σ(intra) = 0.6 W·m–2(S0的0.044%)。 英文
可以认为过去的太阳辐照度周期间变化可能大于这里根据估算β来最小化δTm和δT0之间... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | Ordered Mesoporous Molecular Sieves Synthesized by a Liquid-Crystal Template Mechanism
利用液晶模板机制合成的有序介孔分子筛
Biology
生物
Complete Nucleotide Sequence of the AIDS Virus, HTLV-III
艾滋病病毒HTLV-III的完整核苷酸序列
2.5-Myr Australopithecus boisei from West of Lake Turkana, Kenya
肯尼亚图尔卡纳湖以西250万年前的南方古猿鲍氏种
Forty Years of Genetic Recombi... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0305. 《自然》百年科学经典(英汉对照版)(第七卷)(1985-1992).epub | .epub | 41,865,664 | 2025-09-26T19:07:39.767346 | 海洋浮游植物、大气硫、云反照率与气候
Iron Deficiency Limits Phytoplankton Growth in the North-East Pacific Subarctic
亚北极区东北太平洋海域铁缺乏对浮游植物生长的限制
Evidence for Global Warming in the Past Decade
过去十年中全球变暖的证据
Stratospheric Clouds and Ozone Depletion in the Arctic during January 1989
1989年1月北极上空的平流层云与臭氧亏损
High-Latitude Ozone Loss Outside the... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | 京权图字:01-2011-5392
Original English Text © Nature Publishing Group
Chinese Translation © Foreign Language Teaching and Research Press
This edition is published under arrangement with Macmillan Publishers (China) Limited. It is for sale in the People’s Republic of China only, excluding Hong Kong SAR, Macao SAR and Taiwan... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | Evidence for Extraterrestrial Life: Identity of Sporopollenin with the Insoluble Organic Matter Present in the Orgueil and Murray Meteorites and also in Some Terrestrial Microfossils
地外生命存在的证据:孢粉素与存在于奥盖尔陨星、默里陨星以及一些地球上微化石中的不溶有机质的同一性
Remains of Hominidae from Pliocene/Pleistocene Formations in the Lower Omo Basin, Ethi... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | Inhibition of Prostaglandin Synthesis as a Mechanism of Action for Aspirin-like Drugs
抑制前列腺素合成是阿司匹林样药物的一种作用机制
Aspirin Selectively Inhibits Prostaglandin Production in Human Platelets
阿司匹林选择性抑制人血小板中前列腺素的合成
Indomethacin and Aspirin Abolish Prostaglandin Release from the Spleen
消炎痛和阿司匹林阻断脾脏前列腺素的释放
Possible Clonal Or... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | 大肠杆菌中春日霉素抗性突变与16S核糖体RNA的甲基化变化相关
Problems of Artificial Fertilization
关于人工受精的几个难题
Tyrosine tRNA Precursor Molecule Polynucleotide Sequence
酪氨酸转运RNA前体分子的多聚核苷酸序列
Poly A Sequences at the 3’ Termini of Rabbit Globin mRNAs
兔球蛋白信使RNA 3′末端的多聚腺苷酸序列
On the Mechanism of Action of lac Repressor
关于乳糖操纵子阻遏物的作用机理
Functional ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | Transmission of Kuru from Man to Rhesus Monkey (Macaca mulatta) Years after Inoculation
接种年后库鲁病从人传染到恒河猴(猕猴)
Inhibition of Prostaglandin Synthetase in Brain Explains the Antipyretic Activity of Paracetamol (4-Acetamidophenol)
对大脑前列腺素合成酶的抑制可以解释扑热息痛(4-乙酰氨基酚)的退热作用
A Possible Role for Histone in the Synthesis of DNA
组蛋... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | THE suggestion that Stonehenge may have been constructed with a serious astronomical purpose has recently received support from Hawkins, who has shown1 that many alignments of astronomical significance exist between different positions in the structure. Some workers have questioned whether, in an arrangement possessing... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | (1) The assumption that the Aubrey holes served merely to count cycles of 56 years seems to me to be weak. There is no need to set out fifty-six holes at regular intervals on the circumference of a circle of such a great radius in order to count cycles of fifty-six.
(2) It is difficult to see how it would have been pos... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | markers, and if we know how to move the markers so as to represent the actual motions of the Sun and Moon with adequate accuracy, we can predict almost every eclipse, although roughly half of them will not be visible from the position of the observer. This is a great improvement on the widely scattered eclipses predict... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | Suppose an initially correct configuration for M, N and S is known. The prescriptions enable us to predict ahead what the positions of M, N and S are going to be, and thus to foresee coming events—but only for a while, because inaccuracies in our prescriptions will cause the markers to differ more and more from the tru... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | But now we encounter an apparent difficulty. The minimum of Fig. 2 is very shallow and cannot really be determined in the way I have just described. Angular errors cannot have been less than ±0.25°, and even this error, occurring at the minimum of Fig. 2, is sufficient to produce an error of as much as ±15° in φ. 中文
Th... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | Negative values of the altitude error correspond to cases where it would be necessary to observe below the horizontal plane, if the objects in question were sighted at their extreme azimuths. This is impossible at Stonehenge because the land slopes gently upward in all directions. Such sighting lines could not have bee... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | case of N it obviates any need for the observational work described above. But without observations the correct initial situation cannot be determined unless the problem is inverted. By using observed eclipses the calibrator could be set up by trial and error. This is probably the method of the Saros used in the Near E... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | 第三,根据更加细致的调查,在这些准线中看似存在的量级为±1°的小偏差其实根本就算不上偏差。 英文
在第二篇文章中[2],霍金斯又对早先的一个假说进行了研究,即认为巨石阵可能曾用于预报日月食。月球交点的回归周期为18.61年,这一周期在日月食分析中是非常重要的。霍金斯指出:有一个石标以每年3个洞的速率沿着由56个奥布里洞组成的圆周运动,旋转一周所用的时间恰好是18.67年。这和18.61年非常接近,因而说明月球交点的回归周期与奥布里洞的数量之间是存在相关性的。在这一点上我也同意霍金斯的观点。不过,我与他的分歧之处在于他所说的预测日月食的方式。显然,以下几条对其所持观点的反对意见看起来是合理的:
(1)在我看来,假设奥布里洞仅仅是被用于... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | 当月球在最靠北的角度升起的时候,需要将N定位于γ点,这样每18.61年就可以对标记N进行一次校准。上述方法要求N在循环一周后只能有很小的偏差。如果N的起始位置是正确的,那么它在环行一周结束时只会与真实位置偏离1°左右。日月食预测所允许的误差在大约5°的范围以内,所以如果我们每循环一周就对N点进行一次校准,那么这个预报器将会在误差很小的情况下无限期地发挥作用。还可以用同样的方法把N的初始位置确定下来。 英文
但是现在我们遇到了一个明显的麻烦。图2中的最小值范围非常宽,用我刚刚描述的方法很难真正确定这个最小值点。角度误差不能小于±0.25°,而在确定图2中的最小值时即便只存在这么大的误差,也足以使φ产生±15°的误差。 英文
正确的方法... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | 英文
(孟洁 翻译;肖伟科 审稿)
Stonehenge—A Neolithic “Observatory”
C. A. Newham
Editor’s Note
The astronomical function of the ancient monument of Stonehenge near Salisbury in England is also considered in this contribution by astronomer C. A. (“Peter”) Newham. He proposes that the post holes of the stone circle were used to mark... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | A fairly reliable record of the behaviour of the Moon could be obtained by planting a temporary marker (wooden stake) to align on the point where the winter full-moon appeared above the horizon each year. The indications are such that this was done over a large number of years covering several 18.61-year cycles. Such a... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | However, computed moonrise bearings covering the period of 2000–1000 B.C. were first used in an attempt to determine whether any similarity existed between general grouping of the post holes and a sequence of moonrisings. The data used were kindly supplied by Prof. G. S. Hawkins. His calculations are based on first-ord... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | The pattern of risings that would apply to the early Stonehenge period is more truly represented in groups “B” and “C”. Even so, their arrangements could be subject to slight variations as many individual moons have possible alternative rising positions. This applies in those cases when the Moon reaches “full” during t... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | It seems fair to assume that these and other post holes served a purpose in obtaining preliminary information of the behaviour of the Sun and Moon. Once satisfactory alignments had been established, markers of a more permanent kind would be installed. If the foregoing assumptions were correct, then the long period of t... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | The strong lunar influence with which Stonehenge must now be associated necessitates revision of hitherto accepted explanations of some salient features. Until new evidence is found pointing to the contrary, it is more logical to conclude:
(a) That the small stone (No. 11) in the sarsen circle was intentional, and that... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | 一些迹象表明这样的观测记录工作持续了涵盖多个18.61年周期的时间。这么长的时间足以使测定者发现19年的太阴周期或称默冬章,还可能发现霍金斯所指出的约56年的日月食周期(即:3×18.61=55.83)。然而,可以想象当时人们用如此粗糙的方法来确定这个日月食周期势必会遇到相当大的困难。 英文
假设这些柱坑就是为了达到上述目的而留下的,以此为前提,先将每个柱坑的方位按行的顺序编号,沿着东北方向依次为1到6。 英文
每一行中柱坑的数量以及它们相对于奥布里环中心的方位角列于表1。 英文
表1
圆括号中的数字指的是满月线以外的柱坑,但月亮升起时的第一道光线可以照到这些柱坑。
*这个柱坑位于第2行和第3行之间,并且无法把它归到这两行的任意一... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | 当与从相反方向观察到的落日相联系时,它就可以被作为一种确定月食可能发生时刻的方式了。 英文
关于巨石阵的建造者们是否发现了56年的周期这个问题还停留在猜测层面,但利用一种粗糙的方式预测出即将发生的月食是他们绝对可以做到的。 英文
可以证明:一个人仅借助一些最原始的工具,如木钉和线以及几个木桩就可以得到所需的信息。然而,观测者还必须具有长期坚持进行系统观测的毅力,并会用一种简单的方法通过作记号来记录数字,比如在一根小棍上刻痕或者在一个袋子里装鹅卵石。 英文
毫无疑问,这个过程需要好几代观测者才能完成,并且假如我们相信狄奥多在他的著作中所提到的就是巨石阵,那么坐在执掌这个“球形*庙宇”宝座上的人必定出自于同一个家族,并且一代一代世袭下去... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | In this article we show that UGA is “unacceptable” in our system (Escherichia coli infected with bacteriophage T4) and present suggestive evidence that it is nonsense; that is, that it does not stand for any amino-acid. Theoretical arguments make it likely that there is no transfer RNA (tRNA) to recognize it. The reaso... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | DNA either contains no G–C pairs or, if it does contain one, it is connected to another unacceptable triplet by a G–C to A–T transition. 中文
Table 1. Suppression Properties of X655 and Its Derivatives
Phage stocks were plated on the following strains9: su–, CA244; , CA266; , CA180; , CA265; , CA165; , CA167; and , CA24... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | In each case the identification has been checked by converting the ochre to an amber at the same site. 中文
Tryptophan is represented by the single codon UGG. It would therefore be expected to mutate by transitions to both UAG (amber) and UGA, and thus in such cases amber and UGA mutants should occur in close pairs. The ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0307. 《自然》百年科学经典(英汉对照版)(第五卷)(1966-1972).epub | .epub | 16,876,645 | 2025-09-26T19:07:54.356078 | Unacceptability of UGA. There is very good evidence that the amino-acid sequence coded by the first part of the B cistron is not critical for the function of the gene4. It can be replaced by varying lengths of the A cistron using deletions that join the two genes. Moreover, an extensive (– +) frame shift can be made wi... | 400套付费套装书 |
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