育教僑華頁三張五第四十月七年家僰夏 WAH KID YAT PO
同學
暑期進修專欄
慧出版社主編
新數學(十三
Elementary Modern Mathematics
Lesson 13
Numbers
The distributive Law
Considering addition ditributed
multiplication.
Distributi
(5x
3+20
23%
報日橋
REFERENC
五期星日三月九年一七九一晷公年十六國 民赛中
爭搶、壓逼、腐敗、空虛
學生煩惱四因素 潘家帶著著
有日漸加甚趨勢
也常一成於快,加以穿凿社會並無生老病死的安全保 離你日等教育取編絳先生,不久,成骨蝕接的世界,並能唔得?比在含然不能 種種靑年間顧亦由而興 但營覺得所學的並不能配合让實際生活,對於 │ 空 雅然終日驾考試而忙, :示,拉時,我不龍正,心不惟步,K
閔,美藝及加一倍,於基唯一的希望袞易陸開杳猼化外國升瞑及
中材类高然敗而求死者迷五百人,此款序中鸦世,引起了被迫了在麼追及腐敗的作用下便產生了空 年降班自殺事件共九百九十三宗,北部及上机极因素都有因果關係,有了取
王和,但由共四攝情况可根信本年中國去」 會最近在大食堂攝選的「防止自殺論點!母了埃郗心靈上的空虛,於是有些事生 4)。第二就是會考放榜後,防止落第於一役役。而製校所難得的知識,並不能培無正强 自殺之際財起。袛散瑪利亞防止自殺的人生假,至於如何站立身處世的標準,更無 留黑青年。人數有多少雖然未有公佈者促西生苦限的感覺;而以惋及家庭方面 买加留學的人數比以往任何一年撂多,生敝接近飒熊猴椼階段時,使旅愽自己的前途而 【謝養生調圓讀書,很少在選煜生內心的苦悶,
一生所,空值。更無殘而學會及保人理於
阿他彩學下手。由於术體就有金格形式的 噻液會。起了要在社會,得蠍優的謀生地位,健 的狀態,怒坐不是取際知識,而朵搶娶升 今日卻總生馬上的萨李已到拼命推嗽 五,任何洪方站,张然將無刻不但學業而徹骨。 法界中人王丙崑令部 的戏台性,而两生困的因素,大致可得到的,比目前的烈鳥多,青年除了埋怨史 想选 微母是一切事業所不能猴 否拙的不幸外,又有被壓可冢强:「銘 長
王應德飛加深造
「異,再小學大學,不知勝多少府路嗎?
獵制勝,因此五六歲的克戴便開始猶童此重構| 中鋼新固件加,入成药机能賽馬士这大學深造。
七國形成爭的常現象。以有涯之生,隨無運
「吃知,怎不令人歡喔。
試所容的沉潑,吐
自沉悱阻死心的。
沉陽离成功可
學生
改稱台上在立法:「李利」還稱,因此辦理畫 標準出版社最近出版
標
| 座外。醫生作過無「墨」中阿斯逹运的獸日,
中英算三科升中叢書 北錤即出版日刃借署核定鼎中艺 廣興書局及國光文化服務社代理
免受了急功近利反告 對岸害的醌念影响,於是便一均以今平九月前,配一稱裕。 何华人民际付,地藏而激其子女受優良激臂是無上┐一九七一 歡迎各校集 疑間的。此外面還整個逆心溶的社會,青年不一。各個有誰知答案- 採用,对以健活其上遠 總統可樂,但知港敦育辦得不好的話,作用又如體當中,我化服務社,把語九三三
·夏冷不到薪來近應負這責任的人。小學激育與電導標,林文復習五九號代班 舞时光文 博蚊网 完成了性高,除了可他們無高之外,一些題~擞準升中英文、一號,如話二三六六四 黑河安全保障,加以乃行小麼隱制的酸酯,使有错湖英文特重脑式一篇,地址荷李活道七十
新細、上
Product.
56
We can see clearly the this Law does not
hold:
CELL 中學同學暑期進修專欄臺Œ英父害主碻
無綫電入門
(七)
Introduction to
Radio Technology!
~
Order of operation
Although the Laws of arithmetic operation permits us to carry out a sun more quickly, we still have to be very careful ab the order of operation in order to get accurate answers.
we often met problems which have more than one operation, In that case, grouping. eymbole such as brackets, parentheses and braces
can be found. Sometimes however no such symbols can be found.
Grouping the first two numbers together first, we shall:get 8 Grouping the bat two umbers first we shall get 20 Which one 18 correct
(7)
How a Radio Receiver
Radio waves Travel 300,000,000 metres a second,
1th the electromag Field and the electro-
-static field
angles.
extended wire-
can
Intercept part the radio wave. A signal voltage caress. the wire or a coil mduces. a. voltage: The corl is runed by the variable capacitor to select the: desired frequency Small portable, receivers generally have ferrite rod aerials (antennas)
The Ferrite rod serials
transi-
any:
Li is tuned to the desired station by VC1. Signal voltage resemble the modulaced: wave. The diode rectifies the negative. halves am produces a demodulated wave. Capacitor C1 helps smooth the rádio Frequency peaks to produce the audio output. This could be heard with headphones, but as a rule will pass to an amplifier:
Superhet:
Nearly all receivers are superhets. Superhet is abbreviated from 'supersonic-heterodyne In a superhet, an oscillator generates a signal which is made to beat with, or heterodyne, sig- mals tuned in This produces à fixed frequency which passes. to. an amplifier (T-F)with Fixed tuned circuits. This frequency; is -still above. audibility. The device for this purpose is call. ed frequency changer, mixer, Transistor Frequency. Changed
DO
To prevent confussion, it is universall agreed that in performing mathematical
Operation, we
1) Carrying out multiplications and
divisions first, in the order left to right.
2) Carrying out additions and subtrad-
tion, after operations of multiplication and division. (Also in the order from left to the rigut }
So, in the above example, should be 20.
the correct answer
ere is another example.
100 5 + 3 x 6
(100 +5)+(3 x6)
240
(2406)
3 × 4 ))
20 18-40
•small coupling winding
stor
by: Supplies ;
are: directive.
They pick up. signals best when an. mas axis; through the windings is at right angles
the direction of the transmitter
To choose a signal in the atmosphere, we tune.a circuit to resonance with it. The resonant uency that at which a signal voltage. is de- veloped across the coll Altering the of the variable condenser in the aer
changes the resonant frequency.
pacity
cincui
With a fixed coil L1, moving VC1 from minimum to maxjmum capacity covers a range of frequencies.. or waveband. One band is about 1,500ke to 600ke (medium waves); for other band, ve. select coils OF
ize and induct
·Selecting diffe
wavebands.
L1 is tuned to the desired transmission. L2 transfers the signals to the base B. L3 is the pscillator
with windings connected ra
re
the collector and
bias.
8. R3 is for
If L1 tunes from 600kc to 1500 kc for medium waves. and the later stages are to operate at 455ke, the L3 tunes from 1055 ke to 1955 kc, The ratio frequencies covered by L1 (1055/7 1955) is smaller than frequencies covered by LT (600/1500) so VC2 is smaller or has a capacitor
in seri
fackets or braces are given in. ation, they should be done fire
¥100 +15+ 18 =100
dansee here that even inside the
the above two rules should also
ad strictly to ensure a correct
Demodulation.
TAMM
Pusting the audible programme into the radio wave is called 'modulation", Recovering the sound from the signal 'demodulation' or ection The action of detection can be plained with a simple circuit:
Some receivers have a radio
before the frequency changer.
ency ampliffer This tuned to the desired. station frequency Valvúe receivers operate in a similar
ranged for valves.
when:signats have been converted to a chosen -fixed Frequency, they pass to the intermediate frequency amplifier. Signals have been convertw ed from radio frequency to this if. Laren they vill become a lower, audio frequency