In our country the first adding machine came into being as far back as 1770 in Byelorussia. The words on this machine testify that it was devised and fabricated by Yakobson, a watchmaker and mechanic in a small provincial town.
P. Chebishev, Russian mathematician (1821-1894), was interested in calculators. Among many other mechanisms invented by him there was an arithmometer designed in 1876. In 1912 Academician A. Krilov (1863-1945) constructed a mechanical integrator for solving differential equations.
The first Soviet computer, a small-size electronic computing machine (MESM), was tested at Kiev Electrical Engineering Institute in 1950 under Academician S. Lebedev. In October 1951 it was put into operation. MESM was followed by BESM (a large-size electronic computing machine) in autumn 1952.
Serial production of computers in the USSR has been started since 1953. 1958 witnessed the production of M-20, computers of the first generation.
The 1st generation of electron tube computers was followed by the 2nd generation of transistor computers or those using magnetic logic elements.
In the 60's nearly 30 models of semiconductor computers were developed in our country. Starting with 1964 semiconductor computers URAL, BESM-4 and M-220 were produced.
In the late 60's together with other members of the Council of Mutual Economic Assistance (CMEA) the Soviet Union started on the program of Unified Computer System, the program concerned with the 3d generation of computers with high-speed performance and program compatibility, which means that routines of less powerful computers can be carried out by larger ones. It was in 1972 that automatic sequence manufacture of these computers began.
5. :
¾, ⅜, ¼, ⅔, 1 ½, ⅓, 4 ⅓, 2 ¾, 2 ⅔, 5 ⅞, 5 ¾, 8 ⅔, 0,105 , 2,18 , 17,562 , ⅞ , ⅝ , 3 ⅓ , 2 5/6 , 5%, 23%, 0,36%, 2,5%.
6. :
| 11+23=34 456-27=429 8+5≠10 2∙2≠5 8∙8=64 49:7=7 2⅔∙10 ³√27+√25=8 x≥64 y≤38 √121 ³√64 | √25=5 4x=66 y=6/(x+3) y=-4,5x ⅔∙⅝ ³√8=2 5,6:2,5 5,6∙2,5 ⅞-⅜ 2x/3=9 (2c-10)/9+c/4 0,8x-(0,7x+0,36)=7,1 | x-0,5=2(0,3x-0,2) -10<-4,6<0 -6<m<-15 y/6=1/3 5³∙25 a+b=b+a ab=ba (a+b)+c=a+(b+c) (ab)c=a(bc) a(b+c)=ab+ac S=a² |
7. .
1. n m=2n. 2. t 60t , 60t . 3. , , , : a-b=a+(-b). 4. S=a², S , a . 5. . 6. . 7. . 8. , . 9. , . 10. : 1/6, 7/12, 5/18. 36.
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8. .
1. At room temperature, the conductivities characteristic of metals are of the order of 104 to 106 ohm-1cm-1, while those of insulators may range from 10-22 to 10-10. 2. The concept involved will be illustrated in terms of chemical bonds, by reference to the elements of the Group IV although they are quite general for Solids. 3. The volume to be contained in this column of water is 6 cubic meters. 4. What occurs if we cool the semiconductor up to 0 K? 5. The ratio of forward to reverse current may be very high, for example in silicon rectification ratios of 106 can be achieved. 6. Experts estimate that by the year 2020 we will go by rocket from New York to Tokyo in 30 minutes. 7. Jets speed passengers and mail over the 3,250 air miles separating the two cities in only 6 ½ hours. 8. It was not until the 20th century that electronic computers were constructed and put into operation.
9. .
1. an electric cell/ consist/ does/ of an electrolyte/ two electrodes/ and?
2. found/ of radium/ the atomic weight/ who?
3. the possibility/ was/ to discharge/ demonstrated/ large amounts of energy/ in 1919/ by Rutherford?
4. the voltage/ why/ drop/ to as low as 25 volts/ did?
5. cant they/ as high as 20,000 cycles/ some people/ can hear sounds?
6. eight/, isnt it/ seven times/ fifty-six/ is?
7. mistakes/ how many/ you/ did/ find/ in his calculation?
8. she/ live/ does/ on the 10th floor?
9. you usually/ do/ root-taxi/ take/ number two?
10. , .
| 1. Three seventh plus fourseventhsequals one. | |||||||||||||||||||||||
| a | b | c | d | ||||||||||||||||||||
| 2. Engineers and physicists turned their attention to semiconductors more than | |||||||||||||||||||||||
| a | b | c | |||||||||||||||||||||
| fivety years ago. | |||||||||||||||||||||||
| d | |||||||||||||||||||||||
| 3. The speed of propagation of electromagnetic waves equal to the ratio of | |||||||||||||||||||||||
| a | b | c | |||||||||||||||||||||
| electromagnetic to the electrostatic of charge. | |||||||||||||||||||||||
| d | |||||||||||||||||||||||
| 4. There aretwelfthmonths in a year. | |||||||||||||||||||||||
| a | b | c | d | ||||||||||||||||||||
| 5. The planet Pluto was discoveredseventeen-five years ago, i.e. in the year of | |||||||||||||||||||||||
| a | b | ||||||||||||||||||||||
| nineteenthirty. | |||||||||||||||||||||||
| c | d | ||||||||||||||||||||||
