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C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | (2) Atmospheric analysis. Search for the presence of compounds in the planet's atmosphere which are incompatible on a long-term basis. For example, oxygen and hydrocarbons co-exist in the Earth's atmosphere.
(3) Physical non-equilibrium. A simplified visual search apparatus programmed to recognize objects in non-random... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | . Poisson distributions around the predominant hydrocarbon numbers are shown as solid lines. The inorganic hydrocarbons fit closely the expected Poisson distribution for a state of chemical equilibrium. By contrast the biological hydrocarbons show large departures in the distribution of their abundance from this equili... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | If these conditions are representative of Mars in the past as well as now, there seems no reason to assume that life, if present at all, can resemble that on Earth. However, it is possible that Mars was once Earth-like (primeval non-living Earth) and has changed physically to its present state; or less likely that the ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | I thank A. Zlatkis and P. G. Simmonds of the University of Houston for their advice and for conducting and providing me with the results of the differential thermal analysis experiments suggested in the discussion here. I also thank G. Hobby and G. Mamikunian of the Jet Propulsion Laboratory, California Institute of Te... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 此外,我们也可以接受对生命有限的唯象定义,并根据普遍承认的,包括一些我们所熟知的生命现象设计一些简单的实验,这是可能的。将这种方法应用到生命探测的实验中是下面讨论的基础。
英文
生命的识别
尽管还没有用生化术语对生命作出的正式定义,但用生化实验来区分地球上生命体和无机物质相对来讲是比较简单的事情。例如经验表明,一个能够利用光作为能源,将水、大气中的氮和二氧化碳转换成蛋白质的系统,就不太可能是无机的。这种通过现象表征来识别生命的方法是至今为止提出的探测生命实验的基础。它的缺陷并不在于缺乏正式的定义,而在于假定所有生命的生物化学源头都相同。
英文
也可以用物理实验来区分有生命的和无机的物质。例如,对鲑鱼逆流而上的游动的调查显... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
图1分别显示了来自费–托合成过程的非生物源的烃[8]
和来自生物源羊毛蜡的烃[9]
中碳原子数目在11到33之间的烃的丰度。实线表示的是在含量最多的烃周围的泊松分布。无机烃和化学平衡态所预期的泊松分布很好地吻合了。相反,生物源的烃丰度分布却和这个平衡态有较大的偏离;尤其对于具有较高分子量的烷烃,建立了双碳的有序序列。
英文
图1.来自于费-托烃的无机源(A
),以及来自于生物源羊毛蜡(B
)的n
-烷烃的丰度。在主要烷烃附近,观察到的丰度(●——●)与标准泊松分布(——)的比较。
英文
通过与实验B
1类似的方法,还可以证明与生命有关的不平衡。加热放置在空气中的DTA装置中的几毫克土壤,当与在氩中加... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Giacconi and his colleagues described the discovery of further X-ray sources, many of them near the centre of our Galaxy. The culmination of this work was the launch of the Einstein satellite by the United States in 1978. Giacconi left MIT to become director of the European Southern Observatory in Chile (with an admini... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | a critical evaluation of their experiment which showed that one of the counters did not function as expected. In the same paper they presented results on the atmospheric attenuation of X-radiation from the Scorpius source which was consistent with a black-body temperature of 2-3×106
̊K. In another experiment X-radiati... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | . The efficiency, calculated as the product of the absorption in the gas filling and the transmission of the window, lies above 10 percent between 17 keV and 1.2 keV and peaks at between 3 and 4 keV. This computed efficiency was checked experimentally by exposing counters to the beam from a tungsten target, windowless ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | During each rotation the detector swept out a band on the celestial sphere the width of which, 20 ̊, equalled that of the collimator. The precession results in an approximately sinusoidal variation of the angle of closest approach of a given celestial object to the centre of this band. During each precession cycle the ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | where φ(λ) is an assumed spectrum in terms of number of photons per unit wave-length interval, ε(λ) is the counter efficiency, μ
(λ) is the linear absorption coefficient of the filter and x
is the thickness of the filter. We performed this calculation for three assumed spectra, namely, (1) a power law spectrum of the... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | and a thickness of 1 mm covered by 6.9 mg/cm2
of aluminium. The crystal was viewed by a 7188 CBS photomultipler and the combination had a measured resolution of 48 percent FWHM at 22 keV. The detector field of view was limited to 5 ̊×25 ̊ FWHM and the detector was mounted with its axis at 60 ̊ from the long axis of th... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | -1 is consistent with a cut-off in the spectrum at about 15 keV, whereas the radiation from the Galactic equator region extends to higher energies and there is evidence for a possible peak at 20 keV from the same region. The observation of this peak must be regarded as only tentative because of the low statistical prec... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Numbers listed for 1-10 keV are derived from Geiger counters and those listed for >8 keV are derived from the NaI detector. The listed errors are based on the count statistics and in the case of the integrated power and flux in the 1-10 keV range include the effect of the uncertainty of the spectral index
中文
In the ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | results. The uncertainty in the spectral index yields the uncertainties in the integral quantity. In the >8 keV region the integrated power and photon fluxes were obtained by summing over the NaI pulse-height distribution.
中文
In summary, the results presented here indicate the following:
(1) The ratio of the countin... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
白沙导弹靶场分别于1964年8月28日(第一次飞行)和1964年10月26日(第二次飞行)进行了两次火箭飞行实验,对天蝎座(ScoX
-1)和银道面上银河系中心附近的X射线源进行了探测,获得了大量光谱信息。这些结果由两个独立的探测器获取,能谱范围为1千电子伏~25千电子伏。结果表明,天蝎座X
-1的辐射能谱范围为2.5千电子伏~15千电子伏,但其光谱分布与黑体辐射谱并不一致;来自银河系中心区域的辐射能谱延伸到大约25千电子伏,这一区域明显包括若干不同的X射线源,相关报道可以参见贾科尼等人[1]
、鲍耶等人[2]
和费希尔等人[3]
的研究。
英文
自从贾科尼等人于1962年发现宇宙X射线源以来[4]
,关于... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 当探测器扫过天蝎座X
-1和银道区域,在以上三种滤光片情况下观测到的计数率参见表1,该计数率已经减去了背景计数率。这里的计数率是指在三种情况下进动周期某一小段相同时间内的平均值。表1也给出了滤光片的衰减,定义为两滤光片条件下的计数率与无滤光片条件下的计数率的比值。
英文
表1.不同滤光片条件下两个辐射源区域的计数率
英文
衰减因子的重要性可以由以下分析看出。能量为2.5千电子伏的光子穿过每个滤光片的衰减大约为0.7。滤光片对低能光子的吸收较强,对高能光子的吸收较弱,因此就能量分布而言,为了获得相同的衰减因子,需要对前者进行补偿。所以,在高于和低于2.5千电子伏的范围内,必然存在数目相近的光子数目。衰减的具体数值取决于... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 将以上分析应用于银河系区域计数率比值也会得到相似的结果,即指数谱或幂律谱均可以拟合计数率比值,但是黑体辐射谱给出的碘化钠探测器流量与实际观测值相比几乎可以忽略。原因可能是,若干黑体辐射源都对观测值有贡献,但是其中一个具有数倍于107
K的温度。
英文
图2.碘化钠探测器观测到的计数率的脉冲高度分布
英文
表2.对于两个辐射源区域观测得到计数率和绝对流量
表中给出的1千电子伏~10千电子伏能量范围内的数据由盖革计数器获得,大于8千电子伏的数据来自碘化钠探测器。表中给出的误差来源于计数统计;对于积分功率和流量两栏,1千电子伏~10千电子伏范围内的误差也考虑了光谱指数的不确定度。
英文
对于天蝎座X
-1,如果希... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | X-rays from glass or metal surfaces at very small angles.) In this paper, Giacconi and his colleagues described the detection of three previously unknown X-rays stars based on evidence collected during a rocket flight from White Sands in New Mexico. In the remainder of the decade, Giacconi and his colleagues built sate... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | We obtained the data with a rocket that was launched from White Sands, New Mexico, on October 26, 1964, at a sidereal time of 20h 20m, and reached an apogee of 224 km. Above the atmosphere the rocket spun around its long axis with an almost constant angular velocity of approximately 806 deg/sec. The spin axis precessed... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | is a unit vector in the direction of the spin axis. We define the bearing of a direction to be the sum of its spin azimuth and the precession azimuth of the spin axis. During one complete precession cycle the spin azimuth of a given direction fixed in space decreases non-uniformly by 360 ̊. In the same period the prece... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 30, had effective fields of view of 1.0 ̊×5.2 ̊, with their long dimensions perpendicular to the rocket equator. In our detector designations the number following the letter code specifies the nominal elevation in degrees of the centre of its field of view above the rocket equator. We determined the actual orientations... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 0 produced by various stars repeatedly crossing the field of view showed that the spin frequency increased approximately linearly with time by about 0.2 percent during the useful period of the flight. Thus the bearing of the axis of any given detector, which for constant precession and spin frequencies would be a linea... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | . They are segments of great circles drawn through the precession axis, and they bound the region within which these sources lie. The Kepler's supernova remnant SN
1604 lies 2 ̊ outside this region, and the radio source SgrA
at the galactic centre is just barely within it. The separate peak, the average bearing of wh... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | with respect to the precession equator. Fig. 2a
shows the results for the GV
10 detector. The abscissa is the relative elevation which we define to be the precession elevation of the detector axis at the centre of the indicated bearing interval minus its fixed rocket elevation. The fact that the counting rate was a m... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 20 detectors. In both cases the sources appear to lie about 0.3 ̊ below the midpoint of the elevation scan as indicated by the line crossing the bearing circles D
and E
. We determined these latter bearing circles using only the data from the parts of the precession cycle when the sources gave the highest counting ra... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Finally, we note that there is a striking lack of symmetry with respect to the galactic centre in the distribution of the general X-ray emission from this region. The centre line of the emission region between lines B
and C
in Fig. 3 passes the galactic centre at a galactic latitude of bII
= +2.5. It is also apparen... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 早前在奥斯汀的相对论天体物理学会议上,我们也曾基于相同数据的初步分析报道过这些射线源的位置[1]
。其中一个射线源是天蝎座X
-1(ScoX
-1),由贾科尼等人于1962年首先探测到(参考文献2)。(我们主要根据星座和发现顺序对射线源进行命名,比如,天蝎座X
-2(ScoX
-2)表示在天蝎座中发现的第二个X射线源。)另外两个射线源人马座X
-1(SgrX
-1)和天蝎座X
-2位于银道面附近,先前的一篇论文曾报道过该区域具有一系列的辐射源[3]
。同时我们也找出了可能的第四个X射线源,它位于近似平行于银道但比银道低约4 ̊的大圆中的一段(1 ̊之内)。此外,对开普勒超新星遗迹SN
1604也进行了扫描,但没有... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 然后,我们可以确定进动圆锥轴的指向和进动运动的相位,这需要满足在进动周期内,以上七颗恒星进入和离开星敏感器仰角范围的预计次数和观测次数的均方差最小。这样我们发现,进动轴方向位于赤经302.2 ̊±0.5 ̊,赤纬38.2 ̊±0.3 ̊。通过这些数据,我们可以计算出任意时刻自旋轴的天球方向。反复穿越视场的各个恒星在敏感器SS
0中都会产生近似周期性脉冲,对这些脉冲分析可知,在整个有效的飞行期间,自旋频率大约随时间线性增加了0.2%。因此,任意给定的探测器轴的方位可以表达为时间的二次函数,因为对于恒定进动和自旋频率它是时间的线性函数。在有效观测时间内,方位计算值和实际值之间的平均差值小于±0.5 ̊。
英文
为了确定X射线源和... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
图2c
和图2d
给出了探测器GH
0和GH
20对辐射源观测计数随仰角的变化。在这两种情况下,辐射源看起来大概都位于仰角中点以下0.3 ̊,其中仰角可以由与方位圆周D
、E
交叉线得到。当辐射源产生最大的计数率时,我们可以只采用进动周期的部分数据,确定该方位圆。如前所述,每个交叉点附近的方框代表位置的估计误差。
英文
我们发现,天蝎座X
-1存在两个可以选择的位置,均位于美国海军研究实验室研究小组确定的位置附近半径为2 ̊的不确定圆内[6]
。两个位置中较低的那个距离费希尔等人[7]
确定的位置小于0.5 ̊。
英文
图2.计数率随探测器轴相对仰角的变化,其中仰角是方位间隔中心点对应的值,图中... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | , he concludes that it must be closer than 2 Mpc, and is possibly inside our own Galaxy. However, Schmidt6
has recently announced that the optical object identified with CTA
102 has a red shift z
=δλ/λ of 1.037, and so is probably at a distance comparable with the radius of the universe (~3,000 Mpc).
中文
Although ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | ) days, its thickness cannot exceed 3×1017
/(1+z
) cm. The electrons which radiate at frequencies around 1,000 (1+z
) Mc/s have energies of
ergs, each electron producing ~2.16 ×10–22
H
ergs/sec/(c/s) (where H
is in gauss). If synchrotron self-absorption is occurring, the power radiated from the surface of the di... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | and so
.
中文
If z
~1 the dimensions are: R
~160 parsecs, r
~16 parsecs, and η~15. The lifetime of the electrons is 50-100 years in the fluctuating region, and rather longer in the rest of the source. The total energy of the source is at least ~1057
ergs, of which ~1054
ergs is in the disk. The probability that... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | necessary to detect the possible dispersion, and so to test the hypothesis that there is a significant ionized gas in intergalactic space, and perhaps even to determine the scale-factor of the universe if other radio variables are discovered11
.
中文
We thank Profs. F. T. Haddock, A. Sandage and M. Schmidt for their ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 1965年类星体才刚刚被发现,在当时人们致力于对其同时产生的亮度及周期性变化的辐射机制进行研究。本文中马丁·瑞斯和丹尼斯·夏玛给出了适用于类星体CTA
102的早期解释,他们的观点中最关键的就是提出了存在旋转的盘状物质。尽管他们给出的具体模型很快就被更合适的模型取代了,但是他们的工作有助于给出类星体的大致尺寸并且进一步帮助人们更好地理解能源机制。
英文
根据肖洛米斯基的论文[1]
,类星体[2]
射电源CTA
102(参考文献3)在波长32.5厘米附近存在流量密度变化,周期大约为100天。因此,肖洛米斯基认为,该辐射源的尺寸不可能大于~0.1秒差距,而这恰好是光在一个周期内传播的距离。由于该射电源的角直径不小于0.01... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 我们根据该模型进行如下预测:
(1)流量幅度变化取决于观测频率v
,规律如下:
其中v
的单位为兆周。因此,尽管卡斯韦尔与威尔斯[10]
在178兆周/秒观测不到变化,但这并不一定与肖洛米斯基的观测结果相矛盾。
(2)在300 < v < 1,000频率范围内,流量强度在第t
(v
)天(t
< 50)达到最大,然后在(100-2t
)天内该强度保持不变(换言之,此时盘状区域频率在v
到1,000兆周/秒范围内不再透明)。如图3所示,强度上升时间t
(v
)是关于v
的增函数。
图3. 流量密度的时间变化
(3)除非存在明显的色散,否则对于v
> 300兆周/秒的频率,辐射强度达到最小的时间是一致的。
... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | , and Hawaiian-Chinese-Caucasians11
. This communication concerns the occurrence of haemoglobin J in a Thai family; the family is of special interest because it has haemoglobin E in addition to J.
中文
The presence of an electrophoretically fast-moving haemoglobin in addition to normal haemoglobin A was detected in o... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | those investigations an authentic Thai blood sample with haemoglobins A+E, provided by Dr. Prawase Wasi, Siriraj Hospital, Bangkok, was used for comparison. Numerous studies have reported the presence of haemoglobin E in South-east Asia since its occurrence in Thais17
was initially recognized. Our work13
among the 67... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | All 5 of the living siblings in the second generation of the kindred had E haemoglobins in combination either with A or J haemoglobin. Their mother, I-2, was homozygous for the E haemoglobin gene as illustrated in Fig. 2. Their father is presumed to have had A and J haemoglobins.
中文
The present family provides the f... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Sanghvi, L. D., Sukumaran, P. K., and Lehmann, H., Brit. Med. J.,
ii, 828 (1958).
Huisman, T. H. J., Noordhoek, K., and Da Costa, G. J., Nature
, 179
, 322 (1957).
Lie-Injo, L. E., Acta Haemat
., 19
, 126 (1958).
McCabe, M. E., Lange, R. D., and Crosby, W. H., Amer. J. Med
., 23
, 329 (1957).
Wasi, P., Githens, ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 另外,莱曼博士还对一份中国客家人的血红蛋白样品进行了电泳研究,鉴定它为血红蛋白J。在弄清楚这种泰国人中发现的血红蛋白的结构之前,我们可将其称为血红蛋白J呵叻
以作区别。
英文
随后我们用史密西斯提出的垂直淀粉凝胶电泳方法[14]
研究了该泰国家族中其他16名成员的血液样品,实验在pH 9.0下进行,并选用戈德堡[16]
采用的三羟甲基氨基甲烷–乙二胺四乙酸–硼酸盐缓冲系统[15]
,研究发现该家族的成员中存在E、A+J、A+E和E+J几种类型的血红蛋白组合。该家族血红蛋白表型的分布如图1所示,图2显示了有代表性的血红蛋白的电泳图谱。通过与此前对676名泰国人血样研究时发现的众多其他血红蛋白E和A+E样品的电泳迁移率相比... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
(周志华 翻译;崔巍 审稿)
Haemoglobin E in Vietnamese
R. Q. Blackwell et al.
Editor's Note
In his continuing search for abnormal haemoglobin variants in different ethnic groups, R. Quentin Blackwell and colleagues from the US Naval Medical Research Unit in Taiwan, China, screened 482 Vietnamese hospital inpatients for the ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | On receipt in the laboratory the red cells were washed with saline, mixed with equal volumes of distilled water, and frozen until used for electrophoretic analysis. After thawing, the samples were centrifuged and the supernatant haemolysates examined by Smithies's vertical starch-gel electrophoresis procedure16
. The ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | R. Quentin Blackwell, Jeanette Tung-Hsiang Huang, Li-Chin Chien: Department of Biochemistry, U.S. Naval Medical Research Unit No. 2, Taipei, Taiwan, China.
References:
越南人中的血红蛋白E
布莱克韦尔等
编者按
来自位于中国台湾的美国海军第二医学研究所的昆廷·布莱克韦尔及其同事们,一直在寻找不同种族人群中的异常血红蛋白变异体。他们从越南医院482名住院患者中筛选含有血红蛋白E的患者。在本文中,布莱克韦尔等人报道了17名患者存在血红蛋白E并且总是伴随着血红蛋白A... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Collagen is the main component of connective tissue, present in ligament and tendon, blood vessels, skin and bone. This makes it one of the key structural proteins, which act as materials rather than enzymes. Like many biomaterials, it has a hierarchical structure: the protein strands are woven into triple helices and ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | ). There have since been many reports on the structure of collagen using shadowing, thin sections and positive staining. These have been reviewed in detail by Harrington and Von Hippel6
, Gross7
, Fitton Jackson8
and Veis9
. Much research has been devoted to clarifying the relationship of the basic tropocollagen un... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | ) has been termed the fibrous long spacing (FLS) form. The repeat distance of this form has been found to vary with the method of preparation and the different varieties produced have been further designated FLS—I, II, etc., depending on the spacing observed. In the case of the FLS form of collagen a maximum repeat dis... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | have indicated that the macromolecules are aggregated by end overlap. This view is not in agreement with the model proposed by Schmitt and Hodge13
, in which it is suggested that end-to-end aggregation takes place by a coiling around each other of polypeptide chains projecting from each end of the tropocollagen macrom... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | collagen, also result from regions of bonding between adjacent macromolecules. In native collagen this intermolecular bonding probably consists of polar and hydrogen bonds arising from polar amino acid side-chains arranged in a structurally complementary manner. It thus appears that the tropocollagen units, forming the... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | bands. The precise positions of the ends of tropocollagen macromolecules within the fibrils were difficult to determine. However, on careful inspection of the electron micrographs instances were noted of tropocollagen filaments appearing to end at the edge of an A
band after passing through the band.
中文
We suggest,... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Fig. 2. 1, The diagram illustrates the proposed model for tropocollagen, consisting of a rather flexible filament divided into 9 zones. Five of these are bonding zones and four are considered as non-bonding zones. 1, 2, 3; Association of tropocollagen by random aggregation through bonding zones is illustrated. The over... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | displaced relatively to one another by 0.25 of the molecular length (Schmitt and Hodge13
; Hodge and Petruska21
). Nor is it necessary to suggest an initial polymerization of tropocollagen units by overlapping which is limited to the ends of the molecules, to be followed by “quarter staggering” of the protofibrils (O... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | ). Presumably the glutaraldehyde was able to bridge between amino-groups in the blocked bonding zones to re-establish the native period. These experiments appear to provide clear evidence of the existence of 5 similar zones in the tropocollagen molecule separated by regions having different properties. The three interm... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Fig. 4. 1 and 2, The establishment of a repeat period of 2,500 Å by tropocollagen macromolecules aggregated in the presence of glycoprotein. Linking between intermediate bonding zones is suppressed by glycoprotein, resulting in the observed long spacing. 2 and 3, FLS 1, showing re-establishment of 640- Å period by trea... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | We thank the Wellcome Trust for a grant for the purchase of an electron microscope and ancillary apparatus.
中文
(207
, 822-826; 1965)
R. A. Grant, R. W. Horne and R. W. Cox: Agricultural Research Council, Institute of Animal Physiology, Babraham, Cambridge.
References:
Rich, A., and Crick, F. H. C., J. Mol. Biol.
... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Hodge, A. J., and Petruska, J. A., Fifth Intern. Cong. Electron Microscopy, Philadelphia,
2
, QQ-1 (Academic Press, New York and London, 1962).
Grassman, W., Hannig, K., and Nordwig A., Z. Physiol. Chem.
, 333
,154 (1963).
Petruska, J. A., and Hodge, A. J., Proc. U.S. Nat. Acad. Sci.
, 51
, 871 (1964).
Braun-Falco... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
在对经过负染的胶原蛋白样本的详细研究中,特罗芒[18]
认为明暗带是蛋白质密度和大分子间负染渗透不同导致的。人们发现要证明纤维中大分子末端的准确位置是不可能的,也没有任何证据可以支持霍奇和施米特[19]
的模型所提出的“四分之一交错”排列。最近在对天然胶原蛋白和纤维长间距型胶原蛋白的描述中,奥尔森[16,17]
、库恩和齐默[20]
指出,大分子是通过末端重叠聚集形成的。这种观点与施米特和霍奇[13]
所提出的模型不一致,后者认为原胶原大分子首尾相连聚集的发生是通过其各末端伸展出的多肽链彼此缠绕实现的(霍奇和彼特鲁斯卡[21]
)。
英文
这篇报道是以电子显微镜下观察天然胶原蛋白、片段长间距型胶原蛋白和纤维... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 相邻两个大分子间的重叠可以覆盖1至5个结合区。大分子的方向(箭头所示)决定了胶原蛋白纤维的极性。4,一个640 Å重复模式的建立导致结合区明带(a
)和非结合区暗带(b
)的形成。5,图中(a
)带之间的耦联说明了大分子可能的柔韧性。
英文
没有必要去假设在非结合区间完全不存在极性氨基酸。实际上从交联实验可以知道,在大分子的非结合区有一些赖氨酸的存在。然而在天然纤维中,只有少数分子间的键在非结合区间形成。
英文
当原胶原单位按上述模型聚集在一起时,就为一个分子的结合区以结构互补的方式与另一不同分子的结合区交联提供了最初的随机选择,产生了一条以640Å为周期性的纤维(图2)。按这种方式建立起来的胶原纤维模型与通过负... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
这项研究局限于由胶原蛋白纤维的纵向和横向结构所构成的二维空间上。当前正在进行的工作包括将这一问题扩展到三维空间(截面)上并建立一个三维模型。尽管这只是一个二维空间模型,但聚集是以本质上符合史密斯[25]
标准的随机方式发生的。
英文
图5.图中所示的是观测到的短周期(210 Å~220 Å)的形成。只有当每个大分子都仅能与相邻大分子的部分结合区相互作用的情况下,才可能产生这样的条带。
英文
我们感谢维康基金会为购置电子显微镜和辅助设备提供资金。
英文
(郭娟 翻译;周筠梅 审稿)
Formation of Oceanic Ridges
M. H. P. Bott
Editor's Note
The... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | . This uplift is particularly well displayed in the Colorado Plateau, which remained close to sea-level from before the Cambrian until the early Tertiary and was afterwards uplifted without folding. A similar situation appears to exist where the Indian Ocean Ridge passes into the part of Africa and Arabia which shows e... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Seismic refraction profiles show that changes in crustal thickness are inadequate to explain the uplift of the East Pacific Rise1
(Fig. 2), or the subsidence of the Darwin Rise3
, or the present elevation of the Mid-Atlantic Ridge8
. The region of anomalously low density causing the elevation is therefore within the... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | (1) Iceland lies on the Mid-Atlantic Ridge. The average Bouguer anomaly is about +15 mgal15
. If the upper mantle beneath were normal, this would mean that the crust is continental (30-35 km thick). However, seismic studies in Iceland16,9
suggest that the crust is only about 17 km thick and has a high average P
velo... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | has suggested that the uplift of oceanic rises is reversible. Furthermore, there is no evidence to suggest that equal vertical movements in the opposite sense affect the adjacent belts of ocean floor during the uplift or subsidence of an oceanic rise. These considerations suggest that uplift occurs as a result of dilat... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | The foregoing considerations (1)-(4) together suggest that partial fusion is probably the dominant cause of the low-density region in the upper mantle beneath oceanic ridges and their continental extensions. It remains to demonstrate the feasibility of this hypothesis.
中文
Experiments by Daly20
show that basalt unde... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | is the reduction of confining pressure. Under adiabatic conditions in the field of the solid or liquid phase the reduction in temperature is given by (dT
/dp
)a
· ∆p
, where the suffix refers to the adiabatic gradient. The excess cooling resulting from the steeper fusion gradient provides the latent heat of fusion,... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | The alternative mechanism is that an upwelling mantle convection current causes fusion in its upper reaches (Fig. 4). Since the fusion gradient is steeper than the adiabatic gradient, fusion is restricted to the topmost section of the rising current. As material is carried upwards in the convection current, it follows ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Subsidence of an ocean ridge would occur when the underlying low-density rocks increased in density to the normal value appropriate to their depth. On the convection hypothesis, this would start happening when the convection current died out, causing the source of fresh magma to disappear. The residual magma would part... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | ocean ridges. The hypothesis of partial fusion, however, seems to be consistent with all the lines of evidence.
中文
The only mechanism known for causing magma generation on such a large scale depends on the reduction of confining pressure in an upwelling convection current in the mantle. Such convection currents appe... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 大西洋中脊[2,8]
、部分东太平洋海隆[3]
、冰岛[9]
和美国西部[10]
等地区地幔顶部的地震波速相对较低,即可以作为支持该结论的证据,因为低地震波速通常对应着低密度。
英文
图2.穿过东太平洋海隆的地形和地壳结构剖面图,同时说明了热流和莫霍面下的地震P
波速度。已得作者允许,引自《科学》,第132卷,第1741页,梅纳德[1]
(1960年12月9日)。
英文
上地幔中的相对低密度区,可能是由于化学的非均一性所致,或是由于物理条件的改变而引起正常的上地幔岩石膨胀所致。前者的成因可能是地壳–地幔的混合[11]
或矿物(如斜长石[12]
)组成比例的变化。后者的成因则可能包括:热膨胀,硅酸盐矿物的... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 而围压的下降可能有两种原因:(1)静态地幔的应力释放,(2)地幔对流上升过程中,围压的逐渐减小。这两种过程都与熔融梯度密切相关,该熔融梯度约为6.5°C/千巴~10°C/千巴,即约为2°C/千米~3°C/千米。该数值比地表观测到的绝热梯度高出一个数量级,而比地表观测到的传导温度梯度低一个数量级。
英文
作一个简化的假设:存在某二相边界将液相和固相分开(图3给出了一个熔融带)。当压力(p
)减小时,处于相边界状态的物质一直保持该状态,直到完全熔融。温度(T
)降低了(dT
/dp
)t
·∆p
,其中∆p
是围压的下降值。在绝热条件下,固相或液相区域内温度的降低值为(dT
/dp
)a
·∆p
,其中下标表... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
(孙惠南 翻译;李三忠 审稿)
Submarine Fracture Zones, Aseismic Ridges and the International Council of Scientific Unions Line: Proposed Western Margin of the East Pacific Ridge
J. T. Wilson
Editor's Note
The Canadian geophysicist John Tuzo Wilson made pivotal contributions to the theory of plate tectonics. In a series of pa... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | If this is so, three different guides have been proposed for fitting together the opposite sides of the Atlantic Ocean. The first method is well known and was used by A. Wegener, A. L. Du Toit and E. C. Bullard, J. E. Everett and A. G. Smith5
. It depends on fitting the topography and matching the geology of opposite ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | One possible explanation is that different motions have been recorded. The fracture zones represent the motion of the plates in the crust relative to one another with no reference to the deeper mantle. It has been suggested elsewhere6,7
that the pairs of aseismic ridges perhaps represent the movements of two crustal p... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | as will be shown towards the end of this article, it is an interpretation capable of further development.
中文
In Figs. 1 and 2 the fracture zone Ccc ́C ́
is considered to represent the loci of relative motion of two crustal plates, whereas the two aseismic ridges Bb
and bB
́ each represent the loci of motion of on... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | member of each pair should still be active.
中文
Fig. 4. Diagram showing the relationship of aseismic ridges to fracture zones which they intersect. Note that of each pair one has to terminate at a fracture zone
中文
Some of the chains of islands in the Pacific Ocean seem to meet well the patterns predicted for pair... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | The ICSU Line, Possible Margin of the East Pacific Ridge
Menard shows the western margin of the East Pacific Ridge crossing the Pacific Basin. This margin should surely be discernible and, in seeking to identify it, other known rift margins provide the best possible guide. Heezen and Ewing10
have implied that the Lomo... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | find rates of sedimentation of as much as a few tens of metres in the 1 or 1.5 million years since the Pliocene-Pleistocene boundary, only Pliocene fossils over the crest of the East Pacific Ridge, progressively older Tertiary rocks away from the crest and Cretaceous fossils in the western Pacific only. This is all com... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | Ridge.
中文
(b
) The offsets in the crest and in the pattern of magnetic anomalies should be reflected at the margins. According to A. D. Raff and R. G. Mason16
there are sinistral 900 and 210 km offsets in anomaly patterns across the Mendocino and Pioneer fracture zones. All authorities indicate the Mendocino zone ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | ) All the aseismic ridges in the same crustal plate and on one side of a mid-ocean ridge should be parallel. On the east side of the East Pacific Ridge this is true of the Tehuantepec, Cocos and Nasca ridges and of the small companion ridge to the East (Nasca Two). On the west side it is true of the Gulf of Alaska Seam... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | For the other fracture zones the relationships should be the reverse, and it is true that the Galapagos Islands are still active, even if they scarcely cross the Galapagos zone. The Hawaiian Islands should not cross the Murray zone but appear to do so. This is the only exception, but may be due to a greater complexity ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | The northward motion is absorbed in the Alpine Himalayan and Circum-Pacific Mountains and hence has not affected the Icelandic ridges.
中文
Fig. 6. Left, diagrammatic sketch of an unconstrained pattern of possible crustal and sub-crustal flow; right, the same for a pattern representing in simplified fashion the Earth'... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 此前,转换断层并未引起人们的广泛关注,原因在于它们大多被作为洋底的特征,且多数实例部分或全部位于海底。希森、邦斯、赫西和撒普[4]
最近在赤道大西洋所描述的破碎带已经被引为与大西洋生长相关的右旋型洋脊–洋脊转换断层的典型实例,并被认为这些破碎带连接着海岸两侧曾经相接触的点。这些点可以被称为共轭点。
英文
重建大陆的三种途径
假使如此,人们提出了三种不同的途径将大西洋两岸合并到一起。第一种方法已广为人知,由魏格纳、迪图瓦和布拉德、埃弗里特和史密斯所采用[5]
。它依赖于两岸的地形拟合以及地质学特征的匹配。图1和图2图示说明了A
和A
́区形态的拟合。
英文
第二种建议[6]
指出,在一对无震海岭从大洋中脊上的一个... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 注意:每对无震海岭中必定有一支在破碎带处终结。
英文
太平洋中某些岛链似乎能很好地满足与破碎带相交的成对无震海岭的模型(如图5所示)。这部分是从梅纳德书中图5.7和图6.6复制而来的[9]
。它表示了三条直的平行火山岛链(即纳斯卡海岭、科科斯海岭和特万特佩克海岭),每条都与一个破碎带相交,并明显地在此破碎带终结。特别有意义的是,在东太平洋海隆的另一侧,与纳斯卡海岭大致成镜像的位置分布有南部海岭、社会海岭和土阿莫土–甘比尔海岭。因此可以说明,东太平洋许多岛链与纳斯卡无震海岭或土阿莫土无震海岭平行,并在成因上都与东太平洋洋中脊相关,还预示着那些巨大的东–西向破碎带也与东太平洋洋中脊相关。假如真是这样,并假设转换断层的理论是正确... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 沿内克海岭560千米以上(将近700千米)的右旋位移可能需要将上节提到的海岭南端(靠近内克岛)与莱恩群岛海岭(靠近约翰斯顿岛)对齐,但是不能精确地测量其距离。按照这种解释,夏威夷群岛将具有一种复合构造。
英文
赫斯使我确信在克拉里恩和克里帕顿破碎带可能与莱恩岛海岭相遇的地方存在着偏移。它们似乎还具有合适的方向和长度。由于海图不清楚,我们无法得出关于再往南的破碎带的任何结论。那么该边缘的位移似乎也与理论相一致。
英文
(c
)转换断层应当终止于紧靠边缘处。破碎带在ICSU划线之外更难追踪,而且资料不足以使其成为一个好的验证方法。
英文
(d
)在同一地壳板块内,所有的无震海岭和大洋中脊的一侧都应当是平行的。在东太... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
本文写于我在剑桥大学大地测量学和地球物理学系、地质学系和丘吉尔学院作客之际;在此对他们表示感谢,特别要感谢与布朗、爱德华·布拉德爵士、赫斯、希尔、梅森、马修斯以及瓦因所进行的讨论,这对本文能取得这些结论是非常宝贵的,尽管他们并不完全同意这些结论;同时也感谢休·查普尔和休·瓦因的帮助。
英文
(李任伟 翻译;李三忠 审稿)
An Improved Method for the Characterization of Human Haemoglobin Mutants: Identification of α2
β2
95GLU
, Haemoglobin N(Baltimore)
J. B. Clegg et al... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | A second difficulty usually encountered is the familiar one of incomplete digestion of proteins by proteolytic enzymes. Digestion of human α and β haemoglobin chains with trypsin normally leaves a trypsin-resistant “core” with the result that a region consisting of about 30 percent of the molecule cannot easily be exam... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | but slower than haemoglobin H. These electrophoretic characteristics are similar to those previously described for haemoglobin N4
and the variant has therefore been designated as haemoglobin N (Baltimore). Comparative gel-electrophoresis experiments with other known haemoglobin mutants suggested that at p
H 8.6 haemo... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | H 6.7 with phosphoric acid. The column effluent was monitored continuously at 280 mμ and the resulting chromatogram is shown in Fig. 2. Of the three peaks obtained, two were found at the expected elution volumes of normal α and β chains, while the third peak emerged much earlier than normal β chain, indicating the pres... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | H 8.2 (the amounts of salt introduced by the automatic procedure being sufficient to cause smearing of peptide spots when it was necessary to apply all the digest to a single fingerprint). After digestion was complete, the NH4
HCO3
was removed by repeated freeze-drying. For all the digestions the trypsin/protein weig... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | .) The peptides to be analysed were cut from the fingerprints and eluted with 6 N HCl into 100 μl. capillary disposable pipettes by the method described by Sanger and Tuppy8
. Collection of 30-40 μl. was sufficient to ensure complete removal of the peptide from the paper. The tubes were then sealed, and heated at 105°... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | (1) The chromatographic system enables globin from a heterozygous charged mutant to be resolved quantitatively into all its component chains, thus simplifying subsequent chemical investigations. In addition, the high resolution achieved during chromatography eliminates the need for hybridization experiments to determin... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
在研究人类血红蛋白突变体的过程中,长久以来困扰人们的一个难题是从少量的原始材料中分离出纯的α链和β链。虽然链的分离并不是所有化学研究的必要条件,但分离的α链和β链可使这类研究实施起来更容易。本文中描述的人类血红蛋白多肽链的分离方法比较容易操作,与此前报道的那些方法相比,它具有一个优点,因为它不仅可以分离α链和β链,而且也能从正常的链中分离出带电突变链,进而使得杂合的带电突变体的珠蛋白的全部组成链都得以分离。
英文
经常遇到的第二类难题是,较为常见的蛋白水解酶不完全消化蛋白质。用胰蛋白酶消化人类血红蛋白的α链和β链,通常会留下一个胰蛋白酶耐受的“核心”,结果导致指纹图谱不能容易地检测这个约占整个分子30%的区域。然而琼斯... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 在1%的NH4
HCO3
、pH为8.2的条件下消化少量蛋白质效果会更好(当必须对所有消化物进行单一指纹图谱时,自动化程序引入的盐的量足以引起肽点的拖尾效应)。消化完成后,再通过一次冷冻干燥将NH4
HCO3
除去。对于所有消化物,胰蛋白酶与蛋白质的重量比是1/100。消化物干粉溶于pH为4.7的缓冲液(1.25%嘧啶,1.25%醋酸)中,剩余的2毫克原始蛋白质在相同缓冲液中进行电泳,选用规格为108厘米×57厘米的沃特曼No.3 MM纸,在“瓦索尔”冷却系统中于33伏特/厘米条件下电泳3.25小时。烘干后,在正丁醇∶醋酸∶水∶吡啶(15∶3∶12∶10)的条件下,连夜进行色谱分离(参考文献6)。产生的指纹图谱浸泡在0.02... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
(郑建全 翻译;刘京国 审稿)
The Bath-Tub Vortex in the Southern Hemisphere
L. M. Trefethen et al.
Editor's Note
Because of the rotation of the Earth (and the Coriolis forces thereby established), rotating structures are differently affected in the Northern and Southern Hemispheres. The most familiar example is that cyclones... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | The apparatus was modelled on Shapiro's. It was a tank, 6 ft. in diameter and 9 in. high, with a central drain pipe 0.375 in. in diameter connected to a draining hose. The tank differed from Shapiro's in ways suggested by early difficulties Shapiro and Binnie experienced. It was made of ply-wood instead of metal, to re... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | one run with a settling time of 70 h. One revolution in 3 sec is what one would expect of a ring of particles rotating with the surface of the Earth at the latitude of Sydney, and then brought in from a diameter of 6 ft. to a diameter of 0.375 in., provided the ring conserves its angular momentum.
中文
To provide a co... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | in relation to the room was varied from test to test in an attempt to detect any remaining influence of air currents. Air currents did not appear to be a significant influence in the later tests, but it is our opinion that they are likely to have been the largest of the disturbing influences.
中文
In one early test, a... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | current which persistently maintained a circulation that gave the results we observed, and that a quantitatively comparable, but oppositely directed, air current caused Shapiro's results, There is, in principle, an infinite number of hypotheses that can explain any set of observations. This difficulty in validation of ... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 这显然意味着水移动到水箱中心时的速度太慢,以致底部的黏滞阻尼效应抵消了水的角动量,从而在排放的水流中观测不到明显的角动量。为了使排放速度加快,将水箱上升到离地面30英寸的位置。此后,随着软管排水量的增加,排放进行了大约22分钟,在孔口上方始终能观测到某种形式的旋转。
英文
在随后的五次实验中,静置时间均在18小时以上,均观测到了顺时针旋转。在排水的最初10到12分钟内,没有明显的旋转。然后,随着排水的进行开始产生旋转。在其中的三次实验中,一片漂浮着的直径为0.625英寸的紫红色软木被用来指示旋转。经过18小时和20小时的静置时间后,旋转达到了约8秒/圈的速度,在一次70小时的静置时间后则达到3秒/圈的速度。我们可以推测,3秒/... | 400套付费套装书 |
C:\Users\yuan\Documents\400套付费套装书\04-100套\epub\0306. 《自然》百年科学经典(英汉对照版)(第四卷)(1946-1965).epub | .epub | 35,511,682 | 2025-09-26T19:07:57.651603 | 英文
(沈乃澂 翻译;高守亭 审稿)
The Temperature Scale
Editor's Note
Mechanical engineer John Georgian had recently proposed a new temperature scale based on the MKS (meter-kilogram-second) system of units. Its advantages, he had suggested, lay in eliminating the various gas constants as conversion factors, and in fitting temper... | 400套付费套装书 |
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