A NEW APPARATUS FOR MEASURING SURFACE TENSION.
A NEW APPARATUS FOR MEASURING SURFACE TENSION.
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DOI：
10.1085/jgp.1.5.521
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发表时间：
1919-05-20
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影响因子：
--
通讯作者：
du Noüy PL
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作者：
du Noüy PL
表面张力在生物现象中的作用的重要性是众所周知的，但所有的测量技术要么是复杂的，（静态方法：毛细波动、液滴反弹、毛细喷射、反弹喷射），或长（液滴法），并且希望有一种简单的装置，通过该装置可以测量表面张力，特别是给定液体的表面张力的变化，可以很容易地测量，具有足够的精度。为此，设计了将要描述的装置（图1）。它没有新的原理;它是基于一个环的粘附，或任何其他设计，液体（温伯格）。它只是一个扭力天平，但不是用砝码来测量张力（这是耗时的，并且需要两个读数），金属丝的扭转用于抵消液体膜的张力并使其破裂。指示金属丝扭转程度的刻度盘上的单个阅读给出一个数字，如果该装置先前已经用水标准化，通过简单的比例给出了液体的表面张力。根据表面张力最高的水的线的扭转只有72的事实，我们可以假设，在这些极限内，线的应变与扭转角成正比，因此不需要校正表（见图2）。当然，该装置也可以用于标准测量，在膜撕裂发生后，通过重量简单地迫使杠杆回到其先前的位置。通过使用比较方法，数字是可靠和恒定的，进行一次测量所需的时间不超过15至30秒。只需要很少量的液体，大约1毫升。在一个手表玻璃，但该设备可以固定在这样一种方式，它将只需要0.5毫升。
The importance of the action of surface tension in biological phenomena is well known, but all the techniques of measurement are either complicated (static methods: capillary undulations, drop rebounding, capillary jets, rebounding jets), or long (drop method), and it is desirable to have a simple apparatus by means of which the surface tension, and especially the variation of surface tension of a given liquid, could be readily measured, with sufficient accuracy. For this reason the apparatus to be described has been designed (Fig. 1). There is no new principle in it; it is based upon adherence of a ring, or of any other design, to the liquid (Weinberg). It is simply a torsion balance, but instead of measuring the tension by means of weights (which is time-consuming, and makes two readings necessary), the torsion of the wire is used to counteract the tension of the liquid film and to break it. A single reading on a dial indicating the degree of torsion of the wire gives a figure, which, if the apparatus has been previously standardized with water, gives the surface tension of the liquid by a simple proportion. According to the fact that the torsion of the wire for water, which has the highest surface tension, is only 72, we can assume that, within these limits, the strain of the wire is proportional to the angle of torsion, so that no table of correction is needed (see Fig. 2). Of course, the apparatus may be used for standard measurements also, by simply forcing the lever to come back to its former position by means of weights after the tearing of the membrane has taken place. By using the comparison method, the figures are reliable and constant, and the time necessary to make one measurement does not exceed 15 to 30 seconds. A very small quantity of the liquid is required,--about 1 cc. in a watch-glass,--but the apparatus could be fixed in such a way that it would need only 0.5 cc.