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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 | carboxyl group to the peptide linkage.
中文
It is evident that we must take further circumstances into consideration before we can hope to define rigidly the conditions of action of the various peptidases; in particular, careful attention must be given to electro-chemical effects and to such structural features as 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 | Glycyldehydrophenylalanine is completely resistant towards dipeptidases of plant and animal origin, amino- and carboxy-polypeptidase, trypsin and pepsin. On the other hand, the kidney enzyme is quite unable to attack glycylphenylalanine. It is clear therefore that the kidney enzyme is no ordinary dipeptidase but is ind... | 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 | who has shown that the kidney is capable of dehydrogenating amino-acids and peptides; in these experiments, however, the action of the kidney was not confined to the naturally occurring amino-acids but extended to their optical enantiomorphs, and it is therefore too early to say whether the results are of true biologic... | 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 | Now we have already discussed two synthetic proline peptides, glycyl- and alanyl-proline, which are peculiar in that they are hydrolysed by amino-polypeptidase but not by dipeptidase; moreover, the hydrolysis of such a peptide, when it does occur, will give rise to liberation of a free carboxyl group but not of an amin... | 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 experiments provide an example of a protein digestion in which free amino and carboxyl groups are not liberated in equivalent amounts; such equivalence can therefore no longer be regarded as an essential characteristic of proteolysis. Furthermore, they show in a convincing manner the importance of the individual ... | 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 of gelatin the problem can be simplified to some extent by using the protein in the form of films of uniform size and thickness, so that the surface of protein remains practically constant during digestion; moreover, the course of the digestion can be conveniently followed optically if a black insoluble sub... | 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 key to present-day and future protein chemistry lies in the development of new synthetic methods, and this is the justification for the expenditure of so much time and labour on the improvement of such methods. In these lectures I have described technical advances made during the last few years in my laboratory, wh... | 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 | 迄今为止,人们认为这种转化只能由每一种氨基酸以自身独特的方式发生,这被假想是通过先脱氢然后再水解脱氮这样的过程而发生的,最后形成一种酮酸。
英文
当我们实验室开始进行有关这方面的研究时,还没有任何酶被发现可以催化氨基酸发生脱氢作用。基于无需在此讨论的原因,我们当时的想法是,这样一种脱氢过程可能是在多肽阶段完成的。为了检测这一假说,我们合成了多种不饱和的二肽和三肽化合物,并试图寻找可以水解这些化合物的酶。实际上我们从肾脏中获得了这样一种酶[1]
,它可以进攻甘氨酰脱氢苯丙氨酸,生成甘氨酸、苯基丙酮酸和氨。该酶也能进攻甘氨酰脱氢丙氨酸而得到类似的结果:
甘氨酰脱氢苯丙氨酸完全不被植物和动物来源的二肽酶、氨基和羧基多肽酶、胰蛋白... | 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 | 此外,这些实验以一种令人信服的方式证明,蛋白质中的每一种特定的氨基酸在决定其被蛋白质水解酶作用行为方面的重要性;由于脯氨酸的结构特点,多肽链在脯氨酸通过其亚氨基而连接的位置是不均一的,这种不均一性使特定蛋白质的酶催化降解过程必须按照某种特定的方式才能发生。
英文
我们现在应该可以将话题从对氨基酸、多肽和肽酶的研究中转移到对完整蛋白质的酶催降解过程的简单介绍方面来了。对于能够进攻分子量很高的蛋白质的酶(即蛋白质水解酶),我们还知之甚少,但这些酶的作用是极其重要的,因为它们不仅负责了我们从食物中所摄取的所有蛋白质发生降解的第一步,而且一些非常重要的工业过程也要依赖于蛋白质的酶催降解。
英文
研究蛋白质水解酶作用过程的极其困难... | 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 | between ordinary electrons, “positively charged electrons”, or protons or alpha particles. Today we know that most primary cosmic rays are protons.
中文
T
HERE are three kinds of experiments which seem to afford direct evidence regarding the nature of cosmic rays. These are: (1) the Bothe-Kolhörster double counter ex... | 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 | by the cosmic rays. It would, nevertheless, be surprising if the formulae were in error by so large a factor as five or ten, as would be implied if the coincidences are due to secondary electrons.
中文
(2) If the cosmic rays consist of electrified particles coming into the earth's atmosphere from remote space, the ear... | 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 | whole been negative. Most of the observers conclude that within the errors of experiment the intensity is constant and equal, and those authors who do find differences give their results with certain reservations.”
中文
During the past eighteen months, Prof. Bennett of the Massachusetts Institute of Technology, Prof. ... | 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 | Comparison of the experimental data with the theory of Lemaître and Vallarta shows that the distribution of cosmic rays is about that to be expected if the rays consist of electrons entering the earth's atmosphere in two energy groups. One of these is of such great energy that it is not appreciably affected by the acti... | 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 geographical study of the cosmic rays thus indicates that the less penetrating part of the cosmic rays, at least, consists of high-speed electrified particles. Regarding the more penetrating component, we conclude that if they are electrified particles, they must have an energy of 3×1010
electron volts or more.
... | 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 | depth in the atmosphere at which the cosmic rays are somewhat less than half absorbed, and should then gradually diminish in intensity as sea level is approached. Our high mountain experiments confirm the recent balloon experiments as indicating that no such high altitude maximum exists. This would seem to rule out 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 | On the other hand, if the cosmic rays enter the atmosphere as electrons, they will produce photons just as cathode rays striking a target produce X-rays. Accordingly, at lower altitudes a mixture of electrons and photons will be present, and it may be expected that the photons will have the greater penetrating power. I... | 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,这仍然难以想象,公式的误差会大到5~10倍,以至于认为吸收系数的符合是由次级电子引起的。
英文
(2)如果宇宙射线是从遥远太空进入地球大气的带电粒子,那么地球磁场应该会影响它们的地理分布。斯托默和爱泼斯坦曾对此进行过理论上的研究,最近勒梅特和瓦拉塔又大大完善了这一理论。他们的研究表明:对于能量小于109
电子伏特的电子,它们在接近地球时只能到达纬度约60°以北的地方;对于能量大于约5×1010
电子伏特的电子,其地理分布不受地球磁场的影响;如果能量介于两者之间,入射电子的强度将会按照其能量分布随纬度而异。
英文
克莱在世界各地进行了宇宙射线相对强度的实验研究,他在爪哇与荷兰之间往返了好几次后发现赤道附近的强度总... | 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 | 这些数据表明:随着高度的增加,宇宙射线的强度很快上升,持续呈指数型增长直至15 km高度,从那儿起,当测试仪器接近大气层顶部时,强度达到极限值。
英文
图4. 综合气球实验和在山上所作的实验得到的宇宙射线强度随海拔高度的变化曲线。虚线是把宇宙射线看成光子后的预期值。
英文
假如我们把进入地球大气层的宇宙射线看作是光子,那么在太空中可能与这些光子相关联的次级电子都将因地球磁场的作用而偏离地球。因而我们应该有一束纯光子束进入大气层。在大气层表面,这些光子几乎不会发生电离,因为电离直接由穿过计数室的次级电子产生。然而,这些次级电子只有在吸收了初始光子的能量后才能产生,它们在光子穿越大气层的厚度小于电子的射程时是不会达到其正常... | 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 | limitations on the electron capacity of each band.
中文
W
HEN one metal is alloyed with another, in a series of varying relative proportions, generally several new alloy structures (phases) appear which are different from each other and from the structures of either pure metal. In the usual type of diagram, the compo... | 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 | Such phase diagrams have been worked out for many alloys by metallurgical methods. The boundaries between single phase and two-phase regions are determined by examining polished and etched surfaces under the microscope, and thermal and electrical measurements aid in outlining the diagram. The single phase regions are 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 | positions. If the lattice dimensions of a phase as determined by the powder photograph are plotted against composition, a sloping line is obtained in the single phase region and a horizontal line in the two-phase region. The composition at which the two lines intersect is a highly accurate index of the position 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 | made. The particular feature of the method referred to above is the way in which errors due to incorrect placing of the specimen, absorption in the specimen, film shrinkage, and uncertainty as to camera-radius, are automatically eliminated.
中文
Powder cameras must be calibrated by taking in each camera a photograph 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 | . These alloys, which appear as phases in the copper-zinc and copper-cadmium systems, are obviously similar in nature. They are hard and brittle with a characteristic fracture and sheen. X-ray analysis by Bradley has determined their complex structure, in which there are 52 atoms in the unit cube, the “γ
structure”. F... | 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 | phase, which is body-centred cubic, is found when there are three valency electrons to every two atoms, examples being the alloys CuZn, Cu3
Al, Cu5
Sn. Assigning one valency electron to copper, two valency electrons to zinc, three to aluminium, and four to tin, it will be seen that in the first of these compounds 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 | It is an interesting feature that the metals of the triads iron, cobalt, nickel; ruthenium, rhodium, palladium; osmium, iridium, platinum; form similar phases of the β
and γ
types. In these alloys the valency zero
must be assigned to the transition metals; for example,
3:2 phase FeAl, CoAl, NiAl
21:13 phase Fe5
Zn2... | 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 | alloys, for example, similar atoms occupy certain sets of the sites which are related by the crystal symmetry, and the other atoms occupy the remainder.
中文
Alternatively, we may find the formation of a super-lattice
. In a simple β
structure of the body-centred cubic type, for example, there are two atomic positio... | 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 | Si gives lines identical in arrangement and relation in intensity with those of β
-manganese, in which, of course, all atoms have the same scattering power, so that the scattering by each atomic site must be that of a mean effective atom. Further, it may be noted that the six atoms of Cu5
Si cannot be distributed in ... | 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 | change of axial ratio into the cubic type as the temperature is raised. A similar but simpler case will be discussed here, where the arrangement of the atomic sites remains the same throughout. This is the case in the iron aluminium alloys examined in detail by Bradley.
中文
The alloy of composition FeAl is a structur... | 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 | Al occupying it entirely. Past this point, since one set of cube centres is now full, the further aluminium atoms start filling up the remaining set of cube centres. At a certain point, in order to equalise the distribution between the two sets of centres, these two share the available aluminium until finally at FeAl 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 | The calculation shows that it is impossible to account for the whole range between complete order (which we know to exist by the evidence of super-lattice lines) and complete disorder, in any range of temperature experimentally available. The difference between annealing and quenching could at the most produce a slight... | 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 behaviour of the quenched iron aluminium alloys suggests some such explanation. So long as aluminium is present in quantities less than 25 percent in atomic proportions, there is apparent random replacement. Beyond this point the segregation suddenly appears by which aluminium goes into cube centres alone. May not ... | 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 | 接下来是一段两相共存的区域,这两相中各自都有恒定的组成结构,当从左至右穿过两相区时,第一个相的含量逐渐减少,而第二个相的含量则逐渐增加。第一个相最终消失,从而进入到一个新的单相区,接着是交替出现的两相区和单相区。右端最后一个单相区是作为极限情况的纯金属B
。
英文
人们利用冶金学方法已经完成了很多种合金的相图。通过在显微镜下检查抛光和刻蚀的表面,人们可以确定单相区和两相区之间的边界,热学和电学的测量结果对相图的绘制也有很大的帮助。单相区的边界线并不是垂直的,这表明相的存在范围在某种程度上取决于温度。各个相区上方的液相线和固相线表明熔融态开始凝固和完全凝固时的温度。
英文
近些年来,X射线法在相图的绘制中发挥了重要的作用... | 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 | 事实上,在两种合金中原子的位置几乎相同,而布拉德利指出,处于这些位置上的锌原子在一种合金(Cu5
Zn8
)中的分布方式完全不同于镉原子在另一种合金(Cu5
Cd8
)中的分布方式。很明显,这种独特的复杂γ
结构是由原子分布以外的因素决定的;而原子分布只是受锌原子和镉原子相对大小所影响的次要特征。
英文
我们在各种合金中都发现了类似的相或类似的原子位置排布方式。例如,铜、银、金与副族金属锌、镉、铝、镓、锡的合金可以形成一种与铜、银、金本身一样的面心立方α
相,也可以形成一种体心立方β
相或一种晶胞中有52个原子的复杂γ
相。所有γ
相都有相似的物理性质,比如有极高的硬度。由于在每一个相中原子位置的几何排布都是... | 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 | 这种合金的X射线衍射图显示,作为所有β
相共同特征的体心立方排布所产生的谱线是最主要的特征。此外,由于超晶格的存在还会出现一些附加谱线,这些附加谱线表明该模型单元具有更大的尺度。通过研究这些谱线,我们也许可以了解原子在最适位置中的分布情况。
英文
与形成超晶格或者通常的晶相偏析的状况相反,我们发现在另一些情况下,X射线图仅仅显示出了原子位置的排布,好像原子是以完全随机的方式排布到这些位置上的。这种随机排布会影响到X射线的衍射图案,每个位置就像是被具有平均组成的同一单元所占据一般。可能有很多这方面的例子,韦斯特格伦就给出了一个非常令人吃惊的例子。合金Cu5
Si的结构非常复杂,每个晶胞中有20个原子。它是β
'结构,而非某... | 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 | 如果我们假设上述不利于系统能量的情况会使势能产生一个微小的增量V
,那么就可以计算出一系列温度下处于“无序状态”的原子相对于“有序状态”下的原子的比例。
英文
计算表明,在实验可以达到的温度范围内实现了完全有序(关于这一点我们已经用超晶格谱线证实了)到完全无序的整个变化过程,我们无法对此作出解释。退火和淬火的差别至多只在于少量无序态的产生。不过我们在这里提出的情况并不符合现实。随着结构变得越来越无序,有序位置与无序位置对于某一个给定原子来说差异越来越小,因此V
必然会变小,直到最后达到了一种再也找不到有序判据的状态——原子已完全陷入了混乱无序的状态之中。
英文
然而,看似随机的替换不一定真的就是纯粹的偶然分布。我们可... | 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 | makes it very probable that the positron has a great importance in the building up of nuclei. Anderson2
suggests that the proton may consist of a neutron and a positron. In favour of this hypothesis we may mention the experiments of Stern (still unpublished), who found that the magnetic momentum of the proton is three... | 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
布莱克特、奥基亚利尼[1]
和安德森[2]
探测到了带正电的电子(被人们称为正电子),这很有可能意味着正电子是原子核的重要组成部分。安德森[2]
指出,质子可能是由一个中子和一个正电子组成的。为了证明这个假说,我们要提到斯特恩的实验(尚未发表),他发现:根据狄拉克的理论,如果质子是基本粒子,那么它的磁矩应该是现在的3倍。按照海森堡[3]
的说法,质子和中子都遵循费米统计规律并具有半整数自旋动量。由此我们马上可以得到这样的结论:如果安德森的假说成立,那么正电子应该遵守玻色统计规律并且具有整数自旋动量(0或1)。如果这个观点能够被其他实验现象所证实,那么我们就可以更好地理解为什么正电子只出现在原子核当中;因为正电子具有对... | 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 | help to endow each organ with its peculiar function. But again this is not enough. There is a further requisite, namely, order in the arrangement of the molecules; which gives directive action to the various composite masses. A hair, for example, is largely composed of a species of the proteins known as the keratins. 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 | We have taken a hair as an example, but other parts of the body would have served equally well. Nerves, muscles and tendons all possess arrangement; the bones are not merely shaped externally as an engineer would shape them, but show also in the internal arrangement of their molecules an orientation for a definite purp... | 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 | permanent directional properties except, possibly, at its surface. On the other hand, the mutual arrangement of the molecules in the solid is fundamentally concerned in those directive properties which are characteristic of the solid; it is this arrangement which is now open to our examination.
中文
As illustrations 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 | Resorcinol possesses the same property to a high degree. The molecule is unsymmetrical, being a benzene ring in which two of the hydrogens at points 120° apart are replaced by hydroxyl (OH) groups. The arrangement of the molecules in the crystal has not been determined exactly, but we know that it is at any rate insuff... | 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 is an extremely important point. We obtain from observation on the crystal information respecting the properties of a certain small company of molecules, generally not more than two, three or four. These properties are various: magnetic, electric, optical, thermal and so on. If we determine the arrangement 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 | the arrangement is less regular, the photograph is less definite. When the first photographs were obtained from silk and wool, nerve and muscle, they were in comparison exceedingly vague and it seemed that it would be difficult to make any useful deductions from them. However, both technique and skill in interpretation... | 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 | detail. Two of the simplest are glycine and alanine.
中文
中文
They are characterised by the presence of an amino-group, NH2
, on one side of a certain carbon atom and of a carboxyl group, COOH, on the other. One has a positive character, the other a negative: the two groups have not only a general attraction for 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 | picture—are arranged more or less parallel to one another and to the direction of the fibre. This is the sort of arrangement which we should expect.
中文
Silk fibroin is one of the simplest of the proteins. There are innumerable other possible combinations, because there are many different amino-acids and kindred bodi... | 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 | extension possible in silk: it is not reversible.
中文
A comparison of the two kinds of X-ray photographs supports this conception. The distance of repeat along the chain in stretched wool is only a very little less than that of silk, which is correct if the stretching of the wool is due to the stretching of the chain... | 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 | illustrated by the state of the remains in ancient tombs.
中文
All these facts are illustrative of the statement with which I began, namely, that not only does the arrangement of the atoms in the molecule decide the characteristics of the molecule but also the arrangement of the molecules with respect to each other in... | 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 | Bernal's investigations of the structure of these compounds are an example of one of the two lines along which, broadly speaking, X-ray work is advancing. A series of like compounds is examined, and the various members are compared with each other. Information is derived from observations of the changes as the composit... | 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 is a second line of advance which is being followed; and the two modes of research support each other. In this other method the arrangement of the atoms in very simple crystals is worked out to the bitter end. The method is very laborious and cannot at present be applied to complicated cases. Molecules are chosen... | 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 graphite. It may prove to be the case that the former kind of bond is peculiar to the aromatic substances and the latter to the aliphatic. The heats of combustion of diamond and graphite are very nearly the same: so that it takes as much energy to break down the four bonds in the diamond as the three in the graphite... | 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 | 功能是与取向相联系的,而没有分子排布的特定方式就不可能存在任何取向性,因为迄今还没有人发现活生物体中的某一个过程以与在实验室中观察到的物理和化学定律相矛盾的方向运行。当然,这并不意味着生命已经被赋予了人工排列的原子和分子。如果将大量分子不加区别地排布,以至于无法从中区分出特定的指向,就不可能预期分子能在一个方向上比在另一个方向上更好地伸展和生长,即使它也是活生物体的组成部分。
英文
虽然我们举的例子是毛发,但机体的其他部分也同样可以很好地说明这一问题,神经、肌肉和腱都有其特定的分子排布方式。骨骼不仅在外形上像是被一位工程师塑造出来的,而且其分子的内部排布也体现出一种目的明确的取向性,这足以使工程师自愧不及。
英文
很明显... | 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 | 如果我们确定了单元中的分子排布方式以及分子中的原子排布方式,就可以将性质和排布方式联系起来,这就为物理学中的一个重大难题提供了解决方案,这个难题就是物质的性质与构成物质的原子之间的关系。反过来,知道了一个或多个单元的性质与其具体结构细节之间的关系,我们就可以应用这些知识,通过考察由其他单元组成的晶体的性质,来确定其他单元的结构。
英文
综上所述,各种原子在分子中的位置决定了分子的特性:这是众所周知的,并且人们已经在这方面进行了大量的研究。分子在固体中的位置也具有同样的重要性,尤其是当它们的排布具有某种规律性时,换句话说,就是当要努力得到晶体的时候。活的生物体中必定存在着程度不同的各类分子排布方式。我们想知道这些排布方式是什么样... | 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 | 丝在伸展后不能完全恢复原状。头发在伸展30%之后能完全恢复,超过这个限度之后就只能恢复一部分,不过在断裂前它能被伸展70%。
英文
阿斯特伯里曾指出,如果假定构成所有蛋白质骨架的链都与构成丝的链类似,就可以很顺利地解释这些效应。但在角蛋白中链略有一点皱曲,张力将链拉直而没有使它发生断裂,因此无论什么样的收缩力都能够使链恢复到原来的状态,而且这种伸展和收缩的过程可以不限次地重复。超过30%的弹性伸展后,通过分子相互之间的滑移还存在进一步伸展的可能性。这实际上是丝中唯一可能的伸展形式,它不是可逆的。
英文
比较两种类型的X射线照片可以证实上述观点。如果羊毛的伸展确是由链的伸展所引起,那么在拉伸的羊毛中沿着链方向的重复距离只比... | 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 | 被选来研究的分子中包含广泛存在的羟基、羧基和苯基等原子团,目前已进行的实验表明,原子在这些常见基团中的相对位置和取向总是相同或大体相同的。如果它们是在分析特殊样品时精确测定的,那么所得的规律显然会对结构的确定帮助很大,并且我们也许可以满怀信心地希望在发现一种特定结构是怎样的
同时还能知道为什么
会是这样的。
英文
最近人们在两条发展路线上完成了几项细致的研究。其中的一项结果有助于我们更好地认识碳原子间的连接细节。它在有机化合物的研究中具有特殊的意义,并且可以作为一个例证。人们已经知道碳原子间的键合并不完全相同,我们指的是单键和双键等方式。根据我们现在所能进行的测量,碳的键合至少有两种类型,两者的主要不同在于接近的程度。在金... | 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 March 11, Mr. H. G. Wayling states that “At Lansdowne House on August 1, 1774, Priestley discovered oxygen”; and a similar statement is made by Sir Philip Hartog in the “Dictionary of National Biography”.
中文
Sir Edward Thorpe in his “Joseph Priestley” says, however, that “the course of inquiry which he began at L... | 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 | Soon after this, Priestley visited the Continent with his patron, and met Lavoisier in Paris; but in the following March he was back again in Calne. This is shown by an autograph letter which I have been privileged to see amongst a collection in Dr. Williams's library in Gordon Square. In this letter, Priestley, after ... | 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 should be read in connexion with the following well-known passage from the “Experiments and Observations on Different Kinds of Air”, vol. 2 (1775), p. 40, in which, after referring to his experiment of August 1, 1774, Priestley says:
“In this ignorance of the real nature of this kind of air, I continued from this ... | 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 | (vol. 65, pp. 384—394; 1775); and together with the letter in Dr. Williams's library of March 25, 1775, addressed to Rev. Theophilus Lindsey (the letter to which Prof. Caven refers), these MSS. enable one to trace Priestley's movements at the time. Letter I to Sir John Pringle, president of the Royal Society, is in Pri... | 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 | published. It is probable that Priestley only hesitated about the publication of Letter II because he wished to continue his experiments before publishing them. I am afraid that some of these details may seem meticulous; only the importance of the discovery to which they refer justifies my taking up so much space. 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 | 英文
但是,爱德华·索普爵士在他的《约瑟夫·普里斯特利》中写道,“普里斯特利的探索过程始于利兹,而后他经过孜孜不倦的努力最终在卡恩取得了显著的成果”,而“普里斯特利在卡恩度过的岁月也是他科学生涯中最硕果累累的时期”,我们“不能断定他是否在随后的日子里为我们的知识增添了头等要紧的事实,也不知道后来他是否真的发现了一些重要性可以和他在威尔特郡时的成就相比拟的现象”。
英文
另外,索普还告诉我们,谢尔本勋爵在成为普里斯特利的赞助人时,就“隐居在威尔特郡的博伍德”,而博伍德就在卡恩附近;勋爵为普里斯特利提供了“一所位于卡恩的适合夏天居住的住宅,还有一所位于市内适合过冬的住宅”。
英文
在《不同类型气体的实验与观测》第2卷第34... | 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 | 信件II并未全文出版,实际上只是从1775年4月1日普里斯特利写给牧师理查德·普赖斯博士的信中摘录出来的一部分;为普赖斯的笔录;信中的落款明确为卡恩,4月1日;它被宣读的时间是1775年4月6日。普里斯特利自然会在信中提及他“在伦敦时发现”的气体,因为普赖斯是他的亲密朋友,且他自己是皇家学会的一名会员,普赖斯肯定知道这种气体,也知道他刚刚从伦敦来到卡恩。(给林赛的信说明普里斯特利在3月25日时就已经在卡恩了。)信件III是普里斯特利写给普林格尔的,落款为伦敦,1775年5月24日;它被宣读的时间是1775年5月25日。《自然科学会报》误将信件III的写作日期定为5月25日,还在这些信件开始处的插入段落中错误地把所有三封信的宣读时间都... | 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 | . Judging from the fact that this method when applied to some forty common sources—mostly fruit and vegetable materials—enabled the “minimal antiscorbutic doses” to be calculated to give results in excellent agreement with the values determined directly by biological tests, it is evident that the method has a considera... | 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 | Turning to the animal kingdom, it might have been anticipated that the specificity of the test would be less certain. Nevertheless we found that the suprarenal gland (not hitherto recognised as an antiscorbutic) was very potent, the biological activity agreeing with the value determined chemically; and the same is true... | 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 | to vitamin C, 2.5 gm. per day would suffice as the minimal dose. However, the experimental animals receiving 3.5 gm. lost weight as rapidly and survived no longer than the negative controls, although at death the degree of scurvy appeared less severe. In such tests a complicating factor due to the possible toxic effect... | 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 | Harris, L. J., and Ray, S.N., Biochem. J.
, 26
, 2067 (1932);
Birch, T. W., and Dann, W. J., Nature
, 131
, 469 (April 1, 1933).
Birch, T. W., and Dann, W. J., unpublished work.
Boyland, E., private communication; Biochem. J.
, in the press.
肿瘤以及其他组织中所含的维生素C等还原性物质的化学检测
莱斯利·哈里斯
编者按
在20世纪30年代,化学家和生理学家已经能够定义和描述维生... | 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
总之,考虑到化学试验的适用性问题,可以得出以下结论:与众所周知且广泛应用的利用三氯化锑测定维生素A的试验一样,这种方法即使不算绝对可靠,至少也有价值。当然,对于通常涉及的水果和蔬菜,这种试验似乎不需要进一步的检验就可以得到可靠性很高的结果;而当研究某些特殊物质时,这种试验只能在具备足够相关知识的前提下才可使用。
英文
(李世媛 翻译;秦志海 审稿)
Mitosis and Meiosis
C. L. Huskins
Editor's Note
How chromosomes are partitioned when cells divide was still unclear in the 1930s. Here... | 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 confirmed for other material the initiation of the split occurs one division cycle earlier.)
中文
These observations were stimulated by Darlington's precocity theory of meiosis (which Dr. A. H. Sturtevant in his recent review in Nature
of January 7, p. 5, states that he favours) and the new unified theory has, 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 | split in one division is, of course, essential to reduction. It follows as a mechanical consequence of the preceding stages as here described. The splitting of univalents in both divisions, which occurs chiefly when there are many of them, is apparently due to their delaying the second division and thus permitting 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 | , Proc. Sixth Internat. Cong. Genetics, 2
, 95-96, 392-393 and 396 (1932).
Nebel, B. R., Z. Zell. Micro. Anat.
, 16
, 251-284 (1932).
Sharp, L. W., Bot. Gaz.
, 88
, 349-382 (1929).
Hedayetullah, S., J. Roy. Micro. Soc.
, 51
, 347-386 (1931).
Darlington, C. D., “Recent Advances in Cytology” (Churchill and Co., Lo... | 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 | 他不得不因此而假设尽管在分裂前期单链染色体丝之间是相互吸引的,但在后期它们又会相互排斥。为了避免在理论中出现二重性,达林顿指出[6]
(第48页),“也许是因为......纺锤体着生区......不具备染色单体所具有的可以连接成对的属性。”他还假设(第300页)虽然染色体会在分裂间期分离,但它们的纺锤体着生区却在分裂中期才分开。上述两点假定都缺乏理论上的依据,也与我们的观察结果不符。最后的结论是,尽管达林顿提出早熟论的目的在于统一有丝分裂和减数分裂的机制,但他的基本原理在最后部分(第305页)出现了二重性:“也许所有的细胞核分裂,除了减数第一次分裂以外
[英文斜体是我加上的],都是由染色体的分离决定的。”
英文
根据本文中... | 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 also possible to get a unique structure by excluding the possibility of unattached electrons but allowing the possibility of positrons. The structure is then
where again p'
= 0 or 1 as before. This is practically the suggestion which Elsasser supports.
中文
Using these expressions, we can trace the changes 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 | 我从不同的角度出发用以下证据来反驳这一观点。
英文
如果我们承认原子核有可能是由α
粒子、质子、中子、电子和正电子组成的,那么对于一个原子质量为P
、原子序数为Z
的原子来说,它可能具有的结构个数将随着P
和Z
的增加急剧上升,而重原子可能具有的结构或许会达到数百种。如果我们排除原子核中存在独立正、负电子的可能性,那么就可以认为核结构只能有以下一种形式:
式中p
取0或1,看哪一个值可以使
为整数。
英文
如果只排除独立负电子,而允许独立正电子存在,也可以得到唯一的结构。此时原子核结构为:
和前面一样,p'
取0或1。事实上这就是埃尔萨瑟所支持的观点。
英文
利用这些表达式,我们可以探索放射性元... | 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 | Y holding a conference on “Liquid Crystals and Anisotropic Melts” at the Royal Institution on April 24–25, the Faraday Society has rendered a service not only to the cause of international science but particularly to science in Great Britain, for it has long been a regrettable fact that this interesting and important 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 | The properties of these states are just as definite as those that distinguish the crystalline and liquid states, but they partake, in different degrees, of the nature of both. Their most striking character, though by no means an essential one, is their optical anisotropy, which betrays itself in their spontaneous turbi... | 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 physical explanation of these two types is now fairly clear. In the first place all liquid crystals have very anisotropic molecules, usually—as emphasised by Prof. Vorländer—with one dimension much greater than the others, for example, the classical p-azoxyanisol
or the diethyl-p
-xylylidene-bisamino cinnimate
... | 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 | . Friedel considers it a variant of the nematic
type, but it has many properties also of smectic
states. It is characterised by the production of spectral colours by reflection, with the peculiarity that only right- (or left-) handed circularly polarised light is reflected. This Friedel considers to be Bragg reflecti... | 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 chief business of the Conference was not, however, the discussion of the intermolecular structure of liquid crystals, on which moderate agreement already exists, but the more intricate problem of explaining the texture of liquid crystals, particularly under the action of surface forces and that of magnetic and elec... | 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 | per sec., and certainly suggests the existence of swarms.
中文
As Foëx points out, there is an extremely close parallel between the phenomena of orientation in liquid crystals and those of magnetism, a nematic liquid corresponding to a ferromagnetic, and a normal liquid to a paramagnetic substance, with the transition... | 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 the focal conic structures which has so long remained a puzzle to students of liquid crystals. These structures consist in general of a pair of cones inclined to a common elliptical base, and having as a singular line a hyperbola in a plane at right angles to the ellipse, each conic having its focus at the vertex 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 | It remains to point out the widespread importance of liquid crystals in Nature. This was considered in a paper by Prof. Rinne, whose recent lamented death overclouded the proceedings at the beginning of the Conference. The liquid crystals mostly studied are provided by melts of pure substances: far more, however, are 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 | 19世纪80年代晚期,有人在实验中发现某些液态材料在分子尺度上也具有规整的排列,这在当时引起了人们的质疑。1924年,丹尼尔·福伦德出席了当时在伦敦举行的会议,他在会上解释说,这些液体材料是由棒状分子组成的,它们在移动时也能保持准直排列。威廉·布拉格指出了排列上的缺陷是如何使液晶产生惊人的视觉效果的。用电场控制材料层中分子的排列就是目前液晶显示装置的工作原理。
英文
4月24~25日法拉第学会在皇家研究所举办了关于“液晶和各向异性熔体”的讨论会,通过这次会议,法拉第学会为国际科学事业,尤其是为英国的科学事业做出了贡献,因为长久以来人们一直对英国人不了解这项有趣而重要的课题而感到遗憾。这种无知的程度很深,以至于在《晶体学杂志》有... | 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 | 夫里德耳认为这种现象源于来自间隔相等(间距在不同情况下为1,000~10,000 Å)且分子呈螺旋排布的格朗让平面的布拉格反射。在一篇提交给会议的论文中,奥森试图通过严格运用电磁理论来证明后一种假设足以解释所有的现象,这样格朗让平面就只是一种光学幻觉。夫里德耳坚持认为除了向列相、近晶相和胆甾相之外不存在其他液晶相;然而,福伦德则一直宣称他制备出的物质在固液态之间具有不少于四种的中间态。最近,赫尔曼确认其中除了普通的近晶相之外,还存在着以有面微滴为特征的相,由它们产生的反射不同于由主要平面间隔所导致的反射,这说明分子在近晶相物质的每一层中都是规则排布的(见图4中的第IV种情况)。
英文
图4
英文
这种排布在几何学上是有... | 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 | 在这种情况下谈及黏度会令人误解。正如劳伦斯所指出的那样,其速度分布遵循的规律要比牛顿定律复杂得多,在某些情况下甚至需要考虑弹性力的影响。这些研究的实际价值非常大,因为有很多润滑剂都近似处于液晶状态。
英文
我们仍需指出液晶在自然界中是普遍存在的。林内教授在一篇论文中谈到了这一点,他于不久前去世的消息在会议一开始就给大会笼罩上了悲伤的气氛。人们用于研究的液晶大部分是通过纯净物质的熔融来制备的:然而,在双组分体系中发现的液晶要比在单组分中多得多,在双组分的情况下,溶剂中溶质浓度的增大或减小等价于温度的升高。除了其他一些与分散特性有关的现象以外,这些液晶还可以表现出人们在熔融体中观察到的所有现象,而且双组分体系中的液晶分布广泛,普遍... | 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 far as we know, the only method at present available for the determination of this moment is the deflection of a beam of hydrogen molecules in an inhomogeneous magnetic field (Stern-Gerlach experiment). In the hydrogen molecule, the spins of the two electrons are anti-parallel and cancel out. Thus the magnetic momen... | 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 proton.
中文
This is a very striking result, but further experiments carried out with increased accuracy and over a wide range of experimental conditions (such as temperature, width of beam, etc.) have shown that it is correct within a limit of less than 10 percent.
中文
A more detailed account of these experimen... | 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 | penetrate lead for shorter distances than primary cosmic rays. Rossi's technique spurred the further development of “coincidence-detection” devices for high-energy and nuclear physics. Rossi himself later showed that cosmic rays near the Earth's surface have two components. The first component was ultimately identified... | 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 | (3) When the thickness of the layer is further increased, the frequency of the emerging showers decreases very slowly. The most probable hypothesis to explain this seems to be to assume that a further production of the rays which cause the showers takes place in the layer; these rays are therefore to be regarded as a 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 | 他还发展了一种很灵敏的技术,通过探测三个不同的探测器上几乎同时达到的粒子流来研究这些次级“粒子簇射”。在这篇文章中他指出,在较高原子数元素的物质中,簇射会更多,并且与初级宇宙射线相比,次级粒子在铅中的穿透距离更短。罗西的技术促进了高能物理和核物理学中所使用的“符合探测”装置的进一步发展。罗西本人后来发现,地球表面附近的宇宙射线中存在两种组分,其中一种组分最终被确定是电子和光子,而另一种组分中包含一种被称为μ介子的新型粒子。
英文
去年,我用符合法证明了当宇宙射线穿过物质时会产生次级微粒辐射[1]
。现在,我们根据布莱克特和奥基亚利尼的精巧实验得知这些次级粒子是在所谓的“簇射”中产生的。这一点也可以用符合法来证明;此外,如果我... | 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 statement is occasionally made, and as frequently denied, that cancer is hereditary. It is, of course, clear that environmental influences can play a leading part in determining the production of cancer.
中文
The question is whether nature, as well as nurture, is of importance. By far the most satisfactory evidence... | 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 | spontaneously in one member of a pure line can be transplanted into all other members of it (actually more than 99 percent of successful “takes” can be achieved). Further, it can be transplanted into every F
1
mouse one of whose parents belonged to the pure line, but if these are mated together or outcrossed, only a m... | 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 facts can be explained if the host only reacts to a transplanted tumour so as to destroy it as the result of foreign antigens in that tumour, just as a recipient agglutinates the corpuscles of a donor if they carry foreign isoagglutinogens. On this hypothesis each gene is responsible for the manufacture of a part... | 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 worth nothing that the variance in a mixed population is only about halved when litter mates instead of individuals taken at random are used as controls.
中文
In the same way, Curtis, Dunning and Bullock4
state that in the rat they have found that susceptibility to cancer, on infection with the cestode Cysticer... | 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 contrast with such lines are others with an extremely low susceptibility to spontaneous tumours under ordinary laboratory conditions. A cross between such lines generally gives a hybrid generation with a cancer mortality nearly so high as that of the more susceptible line. Indications of linkage with colour genes ha... | 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 | A particularly clear case of the interaction of nature and nurture in cancer production is found in the case of human xeroderma pigmentosum, almost certainly a recessive character. Here the skin becomes inflamed, and ultimately cancerous, under the influence of light. We could speak with equal logical propriety 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 | To sum up, we can devise conditions under which either nature or nurture will play a predominant part in determining the incidence of cancer. Neither factor can possibly be neglected in a comprehensive survey. Except in a few cases, such as retinoblastoma, our knowledge is not sufficient to warrant interference with hu... | 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 | 假设一个品系X
带有n
对肿瘤生长所必需的基因AABBCC
......,而在品系Y
中没有这些基因,那么F
1
的基因型将是AaBbCc
......,它们将100%能接受移植肿瘤。如果将F
1
和Y
进行回交,那么只有
的个体会携带所有n
个肿瘤生长所必需的基因,而对F
2
来说,
的个体会携带这些基因,因而能够接受移植的肿瘤。在多次试验中,克劳德曼[1]
发现如此计算出来的两个n
值是相同的,这些基因数在2到12之间波动。
英文
与此类似,两个纯品系杂交后的F
1
代个体要产生自发性肿瘤,总体来说,需要其亲本一方提供m
个基因,另一方提供n
个基因。这种情况下,这个肿瘤可以在所有F
1
... | 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 | 另一个品系的动物无论雌雄均有很高发生率的原发性肺癌,而乳腺癌非常少见。第三个品系任何肿瘤的发生都很少,但是肉瘤却较常见。很明显,自发性肿瘤的遗传学机制是非常复杂的,绝对不可能完全归因于某一个显性或者隐性基因的作用。
英文
除了上面所述的研究,还有大量的研究以基因不同源的动物为对象。这些研究结果很清楚地表明,尽管自发性肿瘤的倾向是有遗传性的,但不能归因于单个显性或者隐性基因,而特定的肿瘤发生部位可能也是遗传的。加瓦兹卡亚[6]
在研究特定品系的动物中发现,45只动物中有13只患有枕部肿瘤,而在其他品系,212只动物中仅一只患有此病。但是所有以基因异源性动物为对象的研究都不能令人满意,因为任何个体都可能在达到癌症发病年龄之前死亡... | 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 | Earth's surface; in contrast, ozone at lower levels has harmful health effects and is regarded as a pollutant.
中文
P
REVIOUS estimates of the height of the ozone in the atmosphere, including our own measurements at Arosa1
, agreed in giving the centre of gravity of the ozone layer at about 40–50 km. above sea-level... | 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 | Götz and Dobson, Proc. Roy Soc
., A, 120
, 252 (1928); 125
, 292 (1929).
Götz and Ladenburg, Naturwiss
., 19
, 373 (1931).
Buisson, Janssevan and Rouard, Revue d'Optique
, 12
(1933).
大气中臭氧层的垂直分布
保罗·戈茨等
编者按
在本文中,瑞士科学家保罗·戈茨和两位英国同事报告了他们最近对大气臭氧层垂直分布的测量结果。他们以前测量的大气臭氧质心(本质上就是一个“臭氧层”)约在40~50 km处。现在他们用更精确的方法给出了一个完全不... | 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 blue antimony trichloride coloration given by retinal and choroid layer extracts, when observed spectroscopically, exhibits the sharp, strong band at 620 mμ specific for vitamin A. More concentrated preparations also display the characteristic fainter band at 580 mμ, recently shown to be due to a foreign material w... | 400套付费套装书 |
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