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C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 两种理论均要求有更大的不透明度,并且都超出了现有物理理论的最大值,但是爱丁顿发现米耳恩理论与现有物理理论的差异远远大于他自己的理论。这在很大程度上取决于有多少物质被集中到恒星的中心区。如果只有恒星的中心点具有极高的温度和密度,而恒星其余部分的密度分布几乎与他自己的理论相同,那他或许愿意把这种修正看作是对自己理论的有益补充:这个核将提供一种恒星能源。然而米耳恩把大量的物质安置到恒星中心区,就必定会使已有的关于不透明度的分歧进一步扩大。米耳恩教授反对人们把他的理论称为假说,他认为这样的结果是必然的。这样的结果只有在承认相应前提的条件下才会是必然的,而阿瑟爵士对这些前提持否定态度已有14年之久了。
英文
詹姆斯·金斯爵士觉得自己几乎... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 英文
(林元章 翻译;蒋世仰 审稿)
Present Status of Theory and Experiment as to Atomic Disintegration and Atomic Synthesis
*
R. A. Millikan
Editor's Note
In the mid-1920s, Robert Millikan coined the term “cosmic rays” for the high-energy radiation recently detected in the upper atmosphere. While some physicists suggested that th... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | Following this, and directly dependent upon it, came, second, the discovery, or formulation, of the second law of thermodynamics, which was first interpreted, and is still interpreted by some, as necessitating the ultimate “heat-death” of the universe and the final extinction of activity of all sorts; for all hot bodie... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | and of the correlative one of the heat-death. This last dogma rests squarely on the assumption that we, infinitesimal mites on a speck of a world, know all about how the universe behaves in all its parts, or more specifically, that the radiation laws which seem to us to hold here cannot possibly have any exceptions any... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | radium, and all the allied chain of disintegration products. Since, however, the lifetime of the parent atom, uranium, has now been found to be a billion years or so, we have apparently ceased to inquire whence it comes. We are disposed to assume, however, that it is not now being formed on earth. Indeed, we have good ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | distinction between radiation and matter thus disappeared. These were direct, experimental discoveries. Next, in 1905, Einstein developed the interconvertibility of mass and energy as a necessary consequence of the special theory of relativity. If, then, the mass of the sun could in any way be converted into radiant he... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | therefore available for appearance as heat.
中文
When, about 1914-15, this fact was fitted by MacMillan, Harkins, and others into the demand made above in the fifth discovery for a new source of energy to keep the sun pouring out heat so copiously for such great lengths of time, is seemed to the whole world of physics... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | suns. This discovery, or suggestion, to account for the huge estimated stellar lifetimes, of the complete annihilation of positive and negative electrons within the nucleus, makes it unnecessary to assume, at least for stellar lifetime purposes, the building up of the heavier elements out of hydrogen. Indeed, it seems ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 5. If the foregoing upbuilding process is going on anywhere, the least penetrating and the most abundant radiation produced by it, that corresponding to the formation of helium out of hydrogen, ought to be about ten times as energetic as the hardest gamma rays, that is, it ought to correspond to about twenty-six millio... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 4. A radiation that is completely independent of the sun, the great hot mass just off our bows, and not appreciably dependent on the Milky Way or the nearest spiral nebula, Andromeda, one that comes in to us practically uniformly from all portions of the celestial dome, and is so invariable with both time and latitude ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | obtained from the extrapolation of our predecessors’ curves. This shows that somewhere in the atmosphere below a height of 15.5 km. the intensity of the ionisation within a closed vessel exposed to the rays goes through a maximum, and then decreases, quite rapidly, too, in going to greater heights. We have just taken v... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | Further, the more penetrating the beta rays produced by Compton encounters, the greater the thickness of matter that must be traversed before the beam of pure photons which enters the atmosphere gets into equilibrium with its secondaries; and until such equilibrium is reached, the apparent absorption coefficient must b... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 2. They are due to the building up in the depths of space of the commoner heavy elements out of hydrogen, which the spectroscopy of the heavens shows to be widely distributed through space. That helium and the common elements oxygen, nitrogen, carbon, and even sulphur, are also found between the stars is proved by Bowe... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | Indeed, has not modern physics thrown the purely mechanistic view of the universe root and branch out of its house?
中文
(127
, 167-170; 1931)
Robert A. Millikan: California Institute of Technology, Pasadena, California.
*
Retiring presidential address to the American Association for the Advancement of Science, del... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 这使人们急切地想知道,所有这些由其他元素生成新元素的创造过程,或至少可以说是形成过程,是否不会连续进行——放射性的发现带来了观念上的巨大变化,也有益地告诫了物理学家们要谦虚。然而几年之后,目前已知的两种最重的元素——铀和钍,已被确认都能在生成镭以及一系列相关的衰变产物的过程中得到。既然现在发现作为母原子铀的寿命在10亿年左右,显然我们不用再去追问它是从哪儿来的了。然而,我们倾向于假定它不是现在在地球上形成的。实际上,我们有足够的理由相信所有的放射性过程只局限于极少数很重的元素,它们目前正在释放曾经储存在其内部的能量——我们不知道这种储存是怎样实现的——所以虽然放射现象起初似乎远离了热寂说,可到了最后却不是完全如此。放射现象看起来其实... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 英文
1927年,当阿斯顿对原子的相对质量进行了一系列非常精确的测定,使爱因斯坦在质量和能量之间建立的公式,即E = Mc
2
得到了新的验证之后,第九个里程碑也就出现在了人们的视野中。阿斯顿曲线是我们目前拥有的最具启发性的指证之一。它说明了以下几点:
1. 爱因斯坦方程实际上可用作放射性或衰变过程的有效的定量检验,因而增加了实验的可信度。
2. 放出一个α
射线的放射性或衰变过程肯定只局限于很少几个重元素之中,因为它们在曲线中处于质量可能减少的位置上,因而可以通过这样的衰变过程释放出热能。
3. 所有除氢以外的最常见的元素都处于最稳定的状态之中,也就是说,它们处于质量最小的状态,所以如果我们想让它们发生衰变必须对它们做功,而... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 不过它们肯定是来自宇宙中那些能让它们甚至不必穿透和地球大气层一般厚的物质就可以到达地球的地方——换句话说,宇宙射线必定起源于星际空间深处的超低温区域
。
英文
此外,由康普顿碰撞产生的β
射线的穿透力越强,进入大气层的纯光子束在与它的次级粒子达到平衡之前需要穿透的物质厚度就越大;且当达到此种平衡时,测得的表观吸收系数肯定小于根据辐射产生过程中释放的能量通过克莱因–仁科公式计算得到的系数。因为一年前的博思–柯尔霍斯特实验证明,当入射光子的能量足够高的时候,由康普顿碰撞产生的β
射线确实表现出格外强的穿透力;所以可以预测,如果宇宙射线是在由氢合成像硅和铁这样较重的常见元素时产生的,则所观察到的吸收系数将比根据合成过程可获得的... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | indeed fuel stellar processes at temperatures well below 1.1 × 1013
K, as his earlier arguments had suggested.
中文
I
T has frequently been stated, by myself amongst others, that it is necessary to assume in the inside of stars a temperature of the order of mc2
/k
in order to explain the generation of energy by th... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | In the case under consideration, the annihilation of protons and electrons, it seems difficult to imagine any form of excitation, and the rate at which it proceeds can therefore scarcely depend upon a function of this type. Presumably, in such collisions as are effective, certain circumstances, which occur but rarely, ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 根据热力学定律,一个过程的平衡常数约为e–ε/kT
,在这种情况下ε
是该过程的能量,等于mc
2
。但是平衡常数不能决定能量的产生过程。人们关心的是一个恒星中的能量生成速率;换言之,对最简单的湮灭过程而言,就是质子和电子以辐射形式消失的速率。这类似于化学反应的速率,而不是可逆反应的平衡常数。
英文
在大多数化学作用中,反应速率是由每秒内被激活的分子数目决定的,而这个数目又与能量超过某一特定值(如ε
1
)的粒子数多少相关。因为该值正比于e–ε1
/kT
,所以我们可以粗略地认为,如果温度没有升高到使分子的平均能量接近于激发能,反应速率就可以忽略不计。因为这种激活能通常和反应能具有相同的数量级,所以我们把激活能... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | , was a sufficient description of the nucleus. Within, however, the last three years, the whole attitude of physicists to this problem has changed; on one hand, our knowledge of those phenomena which depend on the intimate structure of the nucleus has been greatly increased; on the other hand, wave mechanics has proved... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | The result of this was that, until a few years ago, while there was a great deal of information about the nuclear spectra of several radioactive bodies, it was still impossible to associate this with any definite feature of the structure. Recently the position has changed greatly, and it now seems possible to view in t... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | radioactive material constitutes an extremely weak source of radiation. As a result it has not yet been possible to push this method when using photographic registration beyond 16 X.U. Recently Steadman2
has devised an arrangement, using an electrical counter in place of a photographic plate, which may overcome some o... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | Fortunately, the radioactive atoms themselves provide us with much more favourable opportunities for observing this photoelectric conversion, by what is termed internal conversion. This is by itself an extremely interesting phenomenon, and will be referred to in detail later. For the present purpose it is convenient to... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | -rays of many radioactive bodies have been analysed by this method, and the main features of the characteristic nuclear spectra are known. The accuracy with which the frequencies can be determined is, however, considerably lower than that realised with X-ray spectra. Even in the case of the bodies radium B and radium C... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | -rays. The interpretation involves a knowledge of the laws of scattering, but there is both a reasonable theoretical foundation and internal evidence from these experiments which combine to render the uncertainties due to this cause of little importance at present.
中文
The photoelectric method has been applied to det... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | -rays, and in the analogous case of X-rays or optical spectra this would be all that could be stated. However, in the case of the radioactive bodies it is possible to define and to deduce the absolute intensities. This depends upon the fact that the process of excitation is due to the disintegration of the atom. When a... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | Applications to the Structure of the Nucleus
The preceding account will have shown the extent to which the spectroscopy of the γ
-rays has advanced. Its application to the problem of nuclear structure is only at the beginning, but it is already possible to indicate the possible lines of advance.
中文
It has been real... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | -particle is excited to one of certain higher states, and that from these states it arrives at the ground state by emitting γ
-rays of frequencies corresponding to the energy differences. It now follows, however, that if an α
-particle can leak out through the potential barrier from the ground level, it can do so sti... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | -particle level of the radium C nucleus with the corresponding nuclear transition formed from the β
-ray spectrum. It seems likely that this line of investigation will lead to definite and valuable results. It is of course quite probable that several nuclear transitions will not be able to be associated with long-rang... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | We have thus no difficulty in seeing, in a general way, how the nuclear energy might be transferred to the electronic system by a direct collision process. Which process, radiation or collision, is predominant can only be settled by experiment, and the answer given by experiment in this case is fortunately unambiguous.... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | responsible for the γ
-rays, or, in other words, should enable the γ
-rays to be associated with a definite part of the nucleus.
中文
While but little has yet been accomplished along these various lines of investigation of the nuclear levels, it is certainly true that the most difficult step has already been made. T... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | γ
射线和核结构的关系就如同普通光及X射线光谱与原子中电子系统结构的关系一样,但是有一点不同:因为激发过程处于控制之下,一系列元素的普通光和X射线光谱很方便进行研究;然而,到目前为止,仅在个别情况下有可能用外部因素激发一个原子核来发射特征辐射。不过,某些放射体可以自发发射这些辐射,因为衰变过程使新形成的核处于激发态,并能发射其特征辐射。因此,只有那些碰巧发射辐射的放射体的核谱得到了详细的研究,迄今为止尚不太可能通过观察接连的一系列不同原子核核谱的相似性来找出支配这些核谱分布的任何普遍规律。
英文
直至几年前,尽管有了关于某些放射体核谱的大量信息,但是仍然不可能将其与原子结构的任何确定特性联系在一起。最近,情况发生了很大的变化... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 其主要原因是,在一个较大的范围内,要获得均匀磁场是有困难的。
英文
γ
射线的强度
斯科别利兹根据γ
射线的康普顿效应已建立了一种研究γ
射线强度的重要方法[4]
。让一束γ
射线的窄光锥通过膨胀室,并以常规方式观测由γ
射线的康普顿效应释放的反冲电子。此外,在膨胀瞬间,施加一个方向平行于膨胀室轴线的磁场,于是反冲电子轨迹的弯曲度取决于其速度。通过观测反冲电子发射轨迹的曲率和方向,可以将每个电子与确定频率的γ
射线联系起来。通过对反冲电子轨迹的相对数进行统计研究,并根据散射的基本定律,可以推导出γ
射线的相对强度。
英文
由于各种实验原因,这种方法的分辨率不是很高,并且也不是总能将两个相邻γ
射线的效应... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 于是可以推出,在镭C的核内,存在一个具有7.68百万电子伏特正能量的α
粒子能级。这一能级给出了建立根据γ
射线推导的能级系统的自然基础。我们可以设想,某些内核排列激发α
粒子,使其到达某一个更高的激发态,然后通过发射频率相当于能量差的γ
射线又从激发态回到基态。然而,如果一个α
粒子在从基态能级穿过势垒时会泄漏,那么它就更容易从激发态能级泄漏。因此我可以预期将发现有一定数量的高速α
粒子与这些衰变模式相对应。
英文
诚然,很久以前我们就知道这类长程α
粒子是存在的,事实上我们已提出过很多将α
粒子群的能量差与γ
射线的频率联系起来的初步建议。然而,目前的观点比这已更进了一步,因为它预测了γ
射线强度与长程... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | Protein Structure and Denaturation
C. Rimington
Editor's Note
It was known since the nineteenth century that heat, acidity or chemical reagents could make soluble proteins coagulate, a phenomenon called denaturation. But no one knew what caused this change. Here industrial chemist Claude Rimington ponders the questio... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | that under appropriate conditions soluble proteins exhibit the phenomenon of surface spreading on liquids, and that all occupy the same surface area irrespective of particle mass (1, 2, 3, or 6 times 34,500). Using Svedberg's common factor 34,500 for the basis of their calculations, the Dutch workers obtain a value for... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | are affected — that is to say, there is no scission. Clearly, loss of isoelectric solubility must be due to change in some internal tautomeric configuration.
中文
It is difficult to avoid the suggestion that a change, similar to that postulated by Astbury and Woods in explanation of the behaviour of the stretched and ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | , 10 (1930).
Gorter and Grendel, Proc. Acad. Sci. Amsterdam
, 32
, 770 (1929).
Anson and Mirsky, J. Gen., Physiol.
, 13
, 469 (1930).
Harris, Proc. Roy. Soc.
, B, 94
, 426 (1923).
Booth, Biochem. J.
, 24
, 158 (1930).
Huang and Wu, Chinese J. Physiol.
, 4
, 221 (1930).
Ott, Kolloidchem. Beih
., 23
, 108 (19... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 通过研究一些蛋白质在不同条件下的表面特性,结合应用X射线法获得这些蛋白膜的衍射图像[8]
,我们就可能在不久的将来揭示出蛋白质的变性过程,或许还能破解天然蛋白的结构。
英文
(韩玲俐 翻译;周筠梅 审稿)
The End of the World: from the Standpoint of Mathematical Physics
*
A. S. Eddington
Editor's Note
This supplement contains a somewhat light-hearted address on “the end of the world” that Arthur Eddington deliv... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | our actual three-dimensional space is believed to have the same kind of connectivity, but naturally the extra dimension makes it more difficult to picture. If we attempt to picture spherical space, we have to keep in mind that it is the surface
of the sphere that is the analogue of our three-dimensional space; the ins... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | at first; but the more widely the matter was scattered the less able was the mutual gravitation to check the expansion. We do not know the radius of space today, but I should estimate that it is not less than ten times the original radius.
中文
At present our numerical results depend on astronomical observations of th... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | , just as the same symbol crops up in distinguishing a closed ellipse and an open hyperbola.
中文
If, then, we are looking for an end of the world—or, instead of an end, an indefinite continuation for ever and ever—we must start off in one of the two time directions. How shall we decide which of these two directions t... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | fact, the one-way traffic in time arises from the way our material bodies are geared on to our consciousness:
“Nature has made our gears in such a way
That we can never get into reverse”.
中文
If this view is right, “the going on of time” should be dropped out of our picture of the physical universe. Just as we have d... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | Leaving aside the guidance of consciousness, we have found it possible to discover a kind of signpost for time in the physical world. The signpost is of rather a curious character, and I would scarcely venture to say that the discovery of the signpost amounts to the same thing as the discovery of an objective “going on... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | There are some important points to emphasise. First, there is no other independent signpost for time; so that if we discredit or “explain away” this property of entropy, the distinction of past and future in the physical world will disappear altogether. Secondly, the test works consistently; isolated systems in differe... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | Let us return to our signpost. Ahead there is ever-increasing disorganisation. Although the sum total of organisation is diminishing, certain parts of the universe are exhibiting a more and more highly specialised organisation; that is the phenomenon of evolution. But ultimately this must be swallowed up in the advanci... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | purpose or design; but I will call it non-committally anti-chance. We are unwilling to admit in physics that anti-chance plays any part in the reactions between the systems of billions of atoms and quanta that we study; and indeed all our experimental evidence goes to show that these are governed by the laws of chance.... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | chance of its being wrong. Let me make a confession. I have in the past twenty-five years written a good many papers and books, broadcasting a large number of statements about the physical world. I fear that for not many of these statements is the risk of error so small as 1 in 1020
. Except in the domain of pure math... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | So, after the world has reached thermodynamical equilibrium the entropy remains steady at its maximum value, except that “once in a blue moon” the absurdly small chance comes off and the entropy drops appreciably below its maximum value. When this fluctuation has died out, there will again be a very long wait for anoth... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | = ∞, the chance will one day come off and the individual concerned will be somewhat surprised to find a lump of ice in his kettle. But it will not happen to me
. Even if tomorrow the phenomenon occurs before my eyes, I shall not explain it this way. I would much sooner believe in interference by a demon than in a coin... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | = ∞, I reply that I cannot possibly accept that as being the explanation of a meeting of the Mathematical Association in t
= 1931. We must be a little careful over this, because there is a trap for the unwary. The year 1931 is not an absolutely random date between t
= –∞ and t
= +∞. We must not argue that because fo... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | sweep it up into a heap at the beginning of time, as I have already described.
中文
The connexion between our entropy signpost and that dynamic quality of time which we describe as “going on” or “becoming” leads to very difficult questions which I cannot discuss here. The puzzle is that the signpost seems so utterly d... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | the wrong way and becoming a positive charge. But in any real experiment we work with apparatus containing billions of particles—ample to give the electron its bearings with certainty. Dirac's theory predicts things which never happen, simply because it is applied to problems which never occur in Nature. When it is app... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | world is inferential. I have no direct acquaintance with my pen as an object in the physical world; I infer its existence and properties from the light waves which fall on my eyes, the pressure waves which travel up my muscles, and so on.
中文
Precisely the same scheme of inference leads us to infer the existence of t... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | but not both halves. Or you can make a compromise and know both halves imperfectly, that is, with some margin of uncertainty. But the rule is definite. The data are linked in pairs and the more accurately you measure one member of the pair the less accurately you can measure the other member.
中文
Both halves are nece... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | This principle is so fully incorporated into modern physics that in wave mechanics the electron is actually pictured in a way which exhibits this “interference” of position and velocity. To attribute to it exact position and velocity simultaneously would be inconsistent with the picture. Thus, according to our present ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | Presidential address to the Mathematical Association, delivered on Jan. 5.
†
This ambiguity is inseparable from the operation of counting the number of particles in finite but unbounded space. It is impossible to tell whether the protons have been counted once or twice over.
‡
I am hopeful that the doctrine of the ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 从旋涡星云的退行速度我们不但可以推算出宇宙最初的尺度,还可以估算出宇宙总的质量,进而得到宇宙中总的质子数。我得出的宇宙中的总质子数为7×1078
或14×1078
。
†
我相信这个数值与静电力和引力的比值有密切的关系,并且只与这个比值的平方相差一个常数因子。如果F
是质子和电子之间的静电力与万有引力的比值,我们得到F
2
= 5.3×1078
。理论上我们有理由相信宇宙中的粒子总数是αF
2
,其中α
是一个简单的几何因子(也许和π
有关)。可能不久我们就能得到α
的理论值,从而给出宇宙膨胀速度的观测值同静电力与引力的比值之间的完整关系。
英文
时间的指示牌
我不能继续讨论跟空间有关的问题,而必须开始讨... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 我们可以用某种称为熵的可测量量来标志这种时间方向上的差别。假设有一个孤立的系统,我们在两个不同的时刻t
1
和t
2
分别测量它的熵S
。因为意识这个概念在数学物理领域里并不是可靠的证据,所以我们想在不靠意识直觉的情况下知道t
1
究竟比t
2
早还是晚。这里用到的规则是:熵越大,时间越晚。在数学形式中为:
dS/dt
总是大于零。
这就是著名的热力学第二定律。
英文
熵是个很特殊的概念,与经典物理学常用的概念很不一样。我们可以把熵简单地描述为:熵是衡量系统无序性的物理量。于是,根据熵这个时间的指示牌,我们得到了这样的规律:从过去到未来,无序性是增加的。物理学发展的最奇妙的特点之一就是:多年来,与其他常规的分析方... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 只有当我们中的某些人被误导着试图穿越几十亿年的时间回到过去时,我们才会发现被我们剔除的所有反几率性现象都堆在那里像一堵高墙一样形成了一个不可逾越的边界,这即是时间的起点。
英文
目前已经有人提出了一种可以解决以上矛盾的方法,这个方法似乎还得到了一些科学工作者的支持。然而,我不同意那种解释,因为我觉得它是站不住脚的,并不是因为我想让这个矛盾继续存在下去。我更愿意去找一个确切的着眼点,但是我确信现在鼓吹的着眼点其实是个死胡同。我必须首先回应对我的一些小的批评意见。
英文
有时,我会因为没有在我所讨论的内容中充分强调熵是概率性而非确定性的物理量而受到批评。如前所述,如果我们在不同的时刻观察同一个系统,那么熵较大的时刻将是较晚的... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 一旦这种事件发生了,而我又找不到其他合适的解释,那么我只能在以下两种极为难以置信的巧合之间做出选择:(a
)这个世界上并不存在物理定律,迄今为止观察到的一致性仅仅是巧合。(b
)这个事件是符合物理定律的,只不过难以置信的巧合事件发生了。我更愿意接受前一种解释,因为数学计算的结果表明它的可能性更高一点。相比于违反物理定律而言,我把难以置信的巧合事件的发生看成是更加糟糕的事情;因为我之所以接受存在于自然界中的物理定律只是因为我相信难以置信的巧合事件不会发生——至少在我有生之年不会发生。
§
英文
同样,如果逻辑上预言在t
=∞之前仅仅是由于原子的随机排列而出现了一个模拟的数学协会的报告会,那我要说的是,我不能接受这就是今天... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 每一个瞬间过后,世界都可能增添一些新事物——这些事物不可能单纯使用数学方法从过去已经发生的事件中推测出来。
英文
确定性的观点占主导地位至少有两个世纪了,确定论认为如果我们知道了某个时刻宇宙状态的完整数据,比如说1600年第一分钟的完整数据,那么单纯的数学推算就可以告诉我们这个世界以前是什么样子以及未来将会是什么样子。未来是由现在所决定的,因为一个微分方程的解由边界条件决定。要理解这个全新的观点,我们必须意识到我们一开始提出的“完整数据”这个概念是存在回避问题实质的风险的。而我们对物理世界的所有认识都是推论性的。我的钢笔并不是作为一个在物理世界中存在的物体使我直接认识到的;我是通过从笔上反射进我眼睛里的光以及握笔时在我肌肉中传... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 现在还存在一两个未得到解决的问题,这使得我不能得出明确的结论,所以我在这里只是给出其中的一种可能性。大家普遍认为物质会慢慢地转变成辐射。如果是那样的话,整个宇宙就会变成一个不断膨胀的充满辐射的球,辐射会变得越来越弱,相应的波长也变得越来越长。大概每过15亿年,宇宙的半径就会增加一倍,宇宙的大小将会以这种几何级数的增长方式永远地膨胀下去。
英文
(沈乃澂 翻译;张元仲 审稿)
*
这篇文章来自爱丁顿于1月5日在数学协会上发表的讲话。
†
这个结果的不确定性与在有限无界的空间中计算粒子数有不可分割的联系。因为我们无法分辨这些质子到底被计算过一次还是两次。
‡
我希望“宇宙膨胀”说会阻止它的发生。
§
毫无疑问,“极... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | H 4.6), which, however, could not be eluted by acid, alkaline or neutral water-alcohol mixtures, or by a dilute solution of saponin. Three extractions with 30 percent propyl alcohol appeared to extract it partially with a considerable loss of activity. Treatment with phosphotungstic acid gives an inactive precipitate a... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 中文
(127
, 594-595; 1931)
B. C. Guha: Biochemical Laboratory, Cambridge.
维生素B2
的化学性质
拜尔斯·钱德拉·古哈
编者按
在这一年中,《自然》杂志对B族维生素的化学性质给予了更多的关注,这篇由印度生物化学领域的重要代表人物——拜尔斯·钱德拉·古哈在剑桥大学完成的论文记述了他在剖析维生素B2
化学性质方面取得的进展。古哈通过一系列实验说明:这种物质——现在被称为核黄素——其实是一种中性化合物,既不是酸也不是碱。古哈指出肝提取物中的维生素B2
与现在认为可以缓解恶性贫血的“因子”不同,这一点对人们来说也许价值更大。后来证明能有效抑制贫血的成分是... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | very compact atomic structures. Degenerate stars of this kind are now most clearly typified by neutron stars, discovered only in the 1960s.
中文
Z
ANSTRA’S recent determination of the temperatures of the O
-stars in planetary nebulae1
makes it appear extremely likely that these stars are all generically in the “whi... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | The masses are, however, certainly greater. In a typical planetary, the line-of-sight rotational velocity can be taken as 5 km./sec. at 6′′ from the nucleus, and with a parallax of 0.002′′ this gives a mass 80 times the sun's.2
If the gas is partly supported by radiation pressure, or if the axis is inclined to the lin... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | degrees. The rate of radiation of such a star is only about 1/100 of that of the sun, or say one calorie per gram in 60 years; taking the specific heat as 3 (when the gas is still on the edge of degeneracy) we see that there is an internal store of heat sufficient for radiation at the white dwarf rate for something of ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | times that of the sun, and where the masses are known the radii are all of about the anticipated size. Particularly high densities are clearly to be expected for the O
-stars. In van Maanen's star, with a radius of 0.007 times the sun, it is tempting to suppose we have a massive star in a very late stage indeed; if Mi... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | The view that the nuclei of planetary nebulae are “white dwarfs” has, we now find, already been propounded by Jeans in “The Universe Around Us”, pp. 309-311. That we had both failed to notice this can be excused, if at all, only by the great popularity of the publication in which the theory was announced, but we sincer... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 英文
很难假设这些白矮星的能源与巨星和主序星的能源是一样的,因此,值得指出的是它们并没有非常明确地表现出对亚原子能源的需要。在进入简并态以前其内部温度的数量级至少是按“扩散”模型计算的主序星温度的50倍,可达109
度。米耳恩对天狼星伴星[3]
的计算表明,其中心温度没有超过(但明显接近)3×109
度。其辐射率仅是太阳的1/100,或者说在60年中每克仅产生1卡路里热能。假设比热是3(当气体仍处在简并态的边缘)我们可以看到如果以天狼星伴星的辐射率计算,其内部的储能足以辐射约1011
年。当然,白矮星即将变为简并态表明,并非原子核和电子的所有动能都将可以用来辐射,大部分动能会以零点能量的形式永久地保留在白矮星内。与此相反,... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | molecules. Astbury and Henry John Woods, his colleague, used this as a starting point for an entirely speculative (and mistaken) account of how protein molecules in general might be constructed.
中文
O
NE of the most satisfactory features of recent advances in the X-ray analysis of compounds of high molecular weight ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | identical with that determined by Svedberg experimentally.”
2. “Three determinations of the sedimentation equilibrium of insulin at a p
H of 6.7-6.8 gave as a mean value for the molecular weight 35,100, which within the limits of experimental error is the same as that for egg albumin, 34,500, and for Bence Jones prote... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | , is a self-contained threefold screw of chains all pointing in the same direction. In Fig. l d
one of the chains has been omitted to avoid confusion, but it will be seen that it is a grouping which is a combination of (b
) and (c
) based on the space-groups D3
3
and D3
4
, and is also a self-contained threefold s... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | are based on the periodic repetition of comparatively simple units, then the probability of disruptive resonance occuring among the constituents of the peptide chain will continually increase with the length, so that excessively long chains would be liable to spontaneous decomposition into shorter chains. We may imagin... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | It is clear, of course, that the wetting agent plays an important part in this permanent destruction of internal tension, but it seems not at all unlikely that vibrational instability also is an essential factor in the process. After treatment of stretched hair with steam, the longitudinal swelling of the fibre in wate... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | Svedberg, T., Nature
, 127
, 438 (1931).
Astbury, W. T., and Yardley, K., Phil. Trans. Roy. Soc.
, A, 224
, 221 (1924). (See Plate 5 (1), (7), Plate 16 (144), Plate 18 (157 and 158).).
Svedberg, T., Trans. Faraday Soc., General Discussion on Colloid Science applied to Biology
, 741 (1930).
Astbury, W. T., J. Soc. ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 已经得到的纤维蛋白的X射线照片显示,蛋白质是由一些相对比较简单的单元通过周期性重复构成的,这些单元带有一些可变的侧链基团。在寻找与这些结果相对应的化学数据时,晶体学家要想办法解释斯韦德贝里的怪异实验结果:许多可溶性蛋白质的“分子量”都是34,500的整数倍。对目前研究情况的最简单的描述可以从《自然》杂志的两篇快报文章[1, 2]
中得知:
1. “近年来关于这种一致性的两项最激动人心的成果分别来自于斯韦德贝里与戈特和格伦德尔。斯韦德贝里巧妙地用超速离心机测定了可溶性蛋白质的分子量,并按“分子量”是公因子34,500的1、2、3、6倍而对它们进行了分级。戈特和格伦德尔的研究则表明,可溶性蛋白质在合适的条件下会铺展于液体表面,此时不管... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 从这种观点来看,蛋白质结构单元的分子量应该不会是严格恒定的,这和实验结果也是吻合的。但很有可能的是,在给定的适宜条件下,许多蛋白质将是由分子量大致恒定的肽链组成的。
*
英文
另一个可能由类似原因导致的现象是关于毛发张力消退的。斯皮克曼发现,被拉直的湿发在保持长度不变的同时张力会逐渐消退[7]
。尽管这些被拉直的头发至少在水中仍能恢复到它原来的长度,但大部分张力的损失是永久性的[8]
。张力消退的速度随着羊毛或头发的类型及浸润溶剂的性质的变化而变化,随着温度的升高而加快。在蒸汽中张力消退的速度非常快。一个短暂的蒸汽处理就可以永久性地改变毛发的载荷–伸展曲线,使纤维的内部结构变松弛,以至于可能使毛发的长度收缩到原长的2/3... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | HE chromosome theory of heredity, by relating chromosome behaviour with the phenomena of inheritance, has obviously made it possible to apply the cytological method to the study of inheritance. With this profitable field before them, geneticists and cytologists have not hesitated to draw conclusions in the one field fr... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | Meiosis consists in the occurrence of two successive divisions of a nucleus in the course of which the chromosomes divide once instead of twice as they would in two ordinary mitoses. Where the distribution of the chromosomes is regular, the four daughter nuclei therefore have half the number of chromosomes of the paren... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | ), and since the chromosomes are qualitatively differentiated, it follows that those which pair and pass to opposite poles must be similar if meiosis is to yield similar reduced nuclei (Boveri). Clearly, likeness is a condition of pairing. But since the chromosomes that pair can be seen to be morphologically alike and ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 中文
Other observations of the same type are : (1) The occurrence of unpaired chromosomes in triploids, instead of all three identical chromosomes of each type being associated (Zea
,4
Tulipa
,5
Lilium
6
). (2) The occurrence of unpaired fragment chromosomes, although these have identical mates with which they can pa... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | After an interval, splits appear in the pachytene thread, separating it into two threads, each of which is now seen to be double. But instead of these splits passing right along the paired chromosomes and separating them entirely, it is found, when they meet, that the double threads that separate in one part are not th... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | These observations point to the chiasmata being the immediate cause of pairing between chromosomes. How can such a hypothesis be tested? It is found that given pairs of chromosomes have a constant range in the number of chiasmata formed. For example, in the M
chromosome of Vicia Faba
12,11
from 3 to 13 chiasmata are ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | the exchanges of partners amongst them; and this attraction exists equally at mitosis.
中文
This being so, we must look to the earliest stage of prophase to find the essential difference between the two types of nuclear division. It evidently lies in the time at which the chromosomes split into their two halves. At mi... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | The first of these tests is applicable to many organisms with occasional suppression of reduction; the aberrant nuclei enter on the prophase of meiosis either earlier or later than the normal nuclei.14,15,16,17
When they are too early, it may be supposed that a premature division of the chromosomes has precipitated th... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | (Fig. 1). We may suppose that this crossing-over has no relation with anything observable cytologically; that it takes place when the chromosomes are intimately associated at pachytene and has no connexion with later behaviour. This view can only be taken when other possibilities are eliminated. We may also assume that... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | of chromosomes of identical structure, it follows that ring formation (where one chromosome pairs in different parts with parts of two others) must always be due to different arrangement of parts, that is, different structure, in the chromosomes contributed by opposite parents.26,27,9
Thus the relationship of the chro... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | Janssens, F. A., La Cellule
, 34
, 135-359 (1924).
Belling, J., Univ. Calif. Pub. Bot.
, 14
(18), 379-88 (1929).
Erlanson, E. W., Cytologia
(in the press) (1931).
Darlington, C. D., Proc. Roy. Soc.
, 107
, 50-59 (1930).
Belling, J., Jour. Genet.
, 18
, 177-205 (1927).
Darlington, C. D., Jour. Genet.
, 20
, 3... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 因为不同对染色体是随机地移向两极的(因此A
1
–A
2
和B
1
–B
2
可以产生子细胞核A
1
B
1
和A
2
B
2
,也同样可以产生A
1
B
2
和 A
2
B
1
),并且由于染色体是定性分化的,如果减数分裂产生的是相似的但染色体数目减少的细胞核,那么进行配对并移向相反两极的染色体也一定是相似的(博韦里)。这显然说明,相似性是染色体得以配对的一个条件。由于配对的染色体在形态学上是相似的,所以可以将它们看作是来自于(就继后进行的观察而言)异性双亲的对应结构(蒙哥马利),这似乎足以说明配对的原因是染色体的相似性。在体细胞有丝分裂时就经常可以看到“萌芽状态”的联会现象,因此,减数分裂很可能是有性生殖过程的最... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 那么怎样才能验证这一假说?研究发现给定染色体对中形成的交叉数都有一个恒定的范围。例如蚕豆的M
染色体[12,11]
在中期可以形成3到13个交叉,平均值为8.1。M
染色体要短很多,可以形成1到6个,平均值为3.0。如果我们假设,断裂产生的小染色体的交叉频率和它们的长度所成的比例与邻近的长染色体一致,那么依据这一假说,我们就可以根据由观测得到的染色体片段长度以及长染色体发生交叉的频率来预测它们的配对频率。因此,我们发现冠花贝母的“黄花”品种中长染色体的交叉频率为2.58,染色体片段的长度约为长染色体的1/9,所以每对染色体片段的交叉频率应为2.58/9,即0.29。这意味着这些染色体片段之间发生配对的比例为0.29(每对染色体... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | 我们也可以假定交换通过断裂及重接成新的线状结构而与交叉存在某种关系,或者是其原因(染色体交叉)[22,23]
,或者是其结果[10,9]
。统计论证表明末端结合与中间交叉的频率是一致的[11]
,而末端交叉增加的数目与中间交叉减少的数目是成相同比例的[3,4,20]
,这就排除了上面提到的后一种可能性。第一种可能性认为当染色体聚集到一起时,原来的染色体就不复存在了。所以染色体在交叉处发生交换或者是由于沿着染色体全长发生线性连续性的交换,或者是由于染色单体之间发生了交换。这一可能性已经从两方面得到了证实。
英文
在四倍体植物风信子属和报春花属中,联会是伴随着一定的空间关系发生的,因此只能将其理解为交换的结果[3,25]
... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | E much regret to announce the death, which occurred on May 9, of Prof. A. A. Michelson, the distinguished physicist of the University of Chicago. Prof. Michelson was probably best known for his wonderful experimental work to detect any effect of the earth's rotation on the velocity of light. At the end of 1929, he resi... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | Collège de France and the École Polytechnique in Paris. Upon his return to the United States in 1883 he became professor of physics in the Case School of Applied Science, Cleveland, Ohio; whence, after six years, he was called to Clark University, where he remained as professor until 1892, when the University of Chicag... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | “Michelson touched on many departments of physics, but in optics, the highest optics, he excelled. In this subject he can be regarded as the most fertile and brilliant disciple of the late Lord Rayleigh, for his inventions are based on a thorough assimilation of the principles of diffraction, interference, and resolvin... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | suppose it was a close double star, and suppose the slits over the object-glass were movable, so that they could be approached nearer together, or separated the whole distance of the aperture apart. A gradual separation of the slits would now cause the fringes to go through periods of visibility and invisibility; and t... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | “ ‘(2) The vanishing of the fringes can ordinarily be determined with such accuracy that single readings give results from fifty to one hundred times as accurate as can be obtained with a telescope of equal aperture.’
中文
“ ‘If among the nearer fixed stars there is any as large as our sun, it would subtend an angle o... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0301. 《自然》百年科学经典（第二卷）(英汉对照版)(1931-1933).epub | .epub | 11,771,588 | 2025-09-26T19:06:58.142679 | diameter of the star.
中文
“So with great skill Michelson and his collaborators got the interferometer to work. After many preliminary adjustments, on Dec. 13, 1920, Dr. F. G. Pease at Mount Wilson, with Michelson's apparatus, measured the diameter of a star for the first time, using Betelgeuse for the purpose. The in... | 400套付费套装书 |
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