踏访亚洲地理中心

去新疆游览的人,大都会慕名走访一个叫"亚心"的地方。"亚心"就是亚洲地理中心。这个地理意义上的亚洲中心,是1992年由新疆科学家们测绘出来并予以定点定位的,距乌鲁木齐市只有30公里,那个地方的原地名叫包家槽子村。离开乌鲁木齐市区去"亚心",汽车一直沿216国道也就是乌鲁木齐河滩公路向西南而行。路况不错,路边风光也好,修剪得很整齐的绿化带,     

野象谷奇遇

野象谷,一个让人终身难忘的地方.前不久我休假,带着小学毕业的儿子,去了云南西双版纳.我们是冲着西双版纳小勐养一个叫三叉河的野象谷自然保护区去的,因为那里是国内惟一有亚洲野象出没的地方.……     

Light-inadequacy of the ultraviolet theory of ionization in the E-layer

From the reports of the CRPL, average yearly values of h′_E, h′_F1,f °_E and N_F1, for the months of January, March, June, July, September, and December of the years 1944 to 1949 were computed and plotted against the magnetic latitude. Altogether some 25,000 individual records were averaged. Seven curves were plotted. They showed that: (1) all curves are symmetrical with respect to the magnetic equator; (2) the h′_E, h′_F1, f⁰_E and the N_F, curves all swing up and down as the magnetic latitude, north and south, increases; (3) the h′_E is definitely periodic with constant period and constant amplitude; (4) the h′_E curve rises only slightly (on the average) with latitude. These results appear to be inconsistent with the ultraviolet light theory of ionization.     

Future developments in transportation

Nearly all prognostigators, from the fellow who buys a $2 ticket on Blue Boy to the financial policy-makers of government and business, base their final conclusions upon past experience. Properly tempered (and herein lies the success or failure of the prophet), this is a completely logical procedure, and is especially applicable to engineering trends, for most of our technical progress has been achieved through a process of evolution.Thus, one of the best ways to gain an insight as to the direction in which we're going is to note our present position and to review how we reached it.In the preceding discussion, I have tried to cover a few specific phases of our transportation future in just this fashion, in order to emphasize that we can expect tomorrow further applications and extensions of the things we are working with today.     

Frequency-coordinate vector diagram

From the standpoint of circuit synthesis as well as for a fundamental comprehension of circuit behavior, it is desirable to be able to visualize the response of a circuit over an extended frequency range by means of a geometrical construction. Mathematically, the response of a circuit can be expressed with the La Place transform theory as a function of the complex frequency variable, p = α + jωw, in which a is the decrement and ω is the “real” angular frequency. Physically, the nature of the real-frequency response is usually not discernible by casual inspection of the mathematical function. This paper develops a means of visualizing this frequency response readily through the construction of a vector diagram from the response function.