12   experiments in vertical

    experiments in vertical means that the revolving bar rotates in the vertical plane. In the experiment, firstly we make the mark M point to the down to collect certain data. Then, we make the mark M point to the upsky to collect enough data. This experiment is called DU (Down-up) experiment according to the direction of the mark M. Typical data are showed in the Fig. 12.01.

Fig.12.01 DU experiments with constant temperature crystal oscillators

   We can find from the figure above that the change of the data is great when we changed the direction which mark M pointed. The space-parameter of series-1, 2, 3 and 4 are showed in the following table.
   Table 12-1

   Among them above, the space-parameter of the series-3 is the biggest reaching 36631, The series -2 and series-4 are almost equal. In theory, the clocks with different heights in gravitational fields are different, when the height difference is h the time difference is following:
    ¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­Equ.12.01
   = 0.002
    However, changes are far over the theoretical expected values, why is so? We turn the pose  of the crystal oscillator at an angle of 90 degrees  to experiment. The result is showed in the following figure.

Fig. 12.02 DU experiment with constant temperature crystal oscillators   2007.01.20

   In the Fig. 12.02, the space-parameter of series-3 becomes the smallest while that of the series-4 becomes the biggest. What is the reason? Eexperiments indicate that caused by the direction change of the gravitation. We can prove by experiments. Move the two crystal oscillators to the center of the revolving bar to experiment, so that the only changed factor is the direction of the gravitation. The result is showed in the Fig. 12.03.

Fig. 12.03 D-U experiments which OCXOs in the center  1/23/2007

The application of vertical experiments
   Since the experiments on vertical planes are extremely sensitive to the gravitational field intensity and the data are perfect repeatable, we can take the advantage of this character to probe the minute change of gravitational fields. It is expected to be used in the researches on physical geography, searching to abnormal areas in gravitational fields, determining the size or the laws of gravity mutation and research the earth's internal structure. We can make a try in many fields, such as geological exploration, searching for mineral deposits and water sources under the ground, studying on earthquakes and military detections and so on.

Measuring the time difference of the gravitational fields
   We are most interested in researches of the gravitational flelds. It is possible to change the heights of the crystal oscillators' rather than the direction, such as the two pallets of a balance. In this way, we can measure the clock's slow effect in gravitational fields because there is much room to improve the time resolution. In the 1990s, Chinese scientist Dr. Yao Xiaotian who was working in NASA invented optoelectronic oscillators which broke the obstacle for the human beings on inventing oscillators. The frequency of this kind of oscillators is higher than the quickest quartz oscillators by one thousand times. And its noisy is lower than that of quartz oscillators. Besides, its frequency isn't affected by environment. Moreover its cost is low.
    Metrical actions can be repeated continually, a different time can be get every time. The measure precision will be improved continually if these result be accumulated continually, Besides, height difference can also be a random value.

The significance of accurate measuring the time difference of the gravitational fields
    1.  It develops a new method to measure acceleration of gravity. We can educe the acceleration of gravity according to the time difference. At present, the acceleration of gravity is commonly measured by static spring gravimeter. Its precision can reach dozens of micro-Gal. In theory, this method can improve the precision unlimitedly. So, its role is obvious.
    2.  We can describe radius-acceleration of gravity curves of the celestial body. Thereby, we can validate the relative theorise of gravitation.
    3. If we get accurate gravity constant, we can test whether or not the gravity constant changes. This is of important theoretical significance.
    4. We can use it to measure accurately the effect of electric and magnetic fields on time, which provides the researchers with means to study on the fields.
    5. There are also other researches, such as doing associate experiments with E tv s experiment, measuring the Gravitational Red Shift accurately, detecting quanta phenomenon of gravitational fields, studying means to shield gravity, detecting gravitational wave etc.

Zhan, Li Kui 6/18/2007

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