VCCI Dayori No.64

EMC on the Internet (No.3)

Good guy or Bad guy ?

Nobuhiko Tsunefuka

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At the beginning of this year, I visited Meiji Shrine and prayed for the economic recovery. It was nice to walk on the front approach to the shrine surrounded by the woods of Yoyogi listening to a refreshing sound that the pebbles make. However, when I go home being tired from the day of work, such a pebbled path just disturbs my feet and the sound I make is not cheerful at all.
A motor and exhaust sound of motorbike that is only annoying to me fascinates some of motorbike fans. Even graceless mobile phone melody may sound sweet to the people who are dying to receive a phone call or e-mail.

It is difficult to define what is good and what is bad because such judgment is heavily influenced by culture, natural environment and religion of countries and areas. A good example is a famous Aesop's fables, "Tortoise and the Hares". Many people think that the turtle is good because it keeps running without taking a rest. However, for the people who live in a desert, the turtle is not fair because it leaves the rabbit behind under the blazing sunshine. In this way, various factors would affect the judgment of bad or good.

A research of comfortable and irritating sound:
http://www2.tamacc.chuo-u.ac.jp/tise/index-j.html

Aesop's fable:
http://www.geocities.co.jp/Bookend/9563/a.html

After a physical examination, I always check about a cholesterol data along with others. Cholesterol is necessary to produce fine cell walls and various hormones. A body produces 1,000 mg of cholesterol every day. Depending on its relative density in blood, it is classified into HDL (High-Density Lipoprotein), LDL (Low-Density Lipoprotein) and others. HDL is commonly called good cholesterol and LDL is regarded as bad cholesterol. It is because active oxygen oxidizes LDL and changes it to oxidized LDL. Microphage decomposes Oxidized LDL, however, the microphage can not decompose all of the Oxidized LDL if it is too much, and the remained Oxidized LDL attaches to the inner wall of blood vessel and makes the diameter of vessel smaller. As a result, the possibility to get arteriosclerosis would increase. It could also cause heart problem such as myocardial infarction and angina pectoris.

As for brain, oxidized LDL could be the cause for cerebral infarction and cerebral hemorrhage. On the other hand, HDL will soften LDL attached to vessel walls and make it easy to be peeled off. So, it helps carrying out cholesterol from vessel and reduce the risk to have heart disease. This is why HDL is called "good cholesterol". Apheresis treatment uses absorption column instead of HDL to absorb and eliminate LDL in blood. As the name indicates, active oxygen that oxidizes LDL is active and strong. To germs that entered a body, active oxygen also responds very quickly oxidizing and disinfecting them to make harmless. In this way, certain level of active oxygen is good to increase immunity. However, when ultraviolet rays created a large volume of active oxygen, it will harm skin and create speckle. In addition, a liver is always active about creating active oxygen and does not stop the production. When the function of liver is weak, the liver will be vulnerable to active oxygen. In this case, active oxygen is treated as a bad element

Cholesterol:
http://plaza.harmonix.ne.jp/~lifeplus/text/colest.html

Active oxygen:
http://www2.health.ne.jp/bknumber/2000084.html

Dry winter in Japan easily causes static electricity. People often feel a zap when they take off a sweater and touch metal products such as a car door. Static electricity also makes TV display and plastic dusty because they are statically charged and adsorb dust that is bearing the electricity of the opposite charge. When some material with some potential is placed adjacent to or collided with some other material with the different potential, there occurs ESD (Electro-Static Discharge). Electrical current caused by ESD will flow into the electrical appliances to damage or destroy the semiconductor on a circuit board embedded inside. Impulsive electromagnetic wave caused by ESD may also lead malfunction of electric circuits. This occurs intermittently, so it is hard to detect. Many high-technology products including LSI, GMR head of HDD are vulnerable to static electricity. One of the counter measures to eliminate such "bad" static electricity is to keep the level of humidity of a room at 60% or higher. This will prevent the emergence of static electricity. Other preventive measures are spraying ions, neutralizing with soft-X ray and preparing a safe path for the charge and discharged current. On the other hand, statistic electricity is necessary for a printing process of laser printers, PPC copiers and an absorption process of hair-transplant machines, electro-statistic painting machines, air cleaners and dusters. It is said that unbalance between plus ion and minus ion will make people tired. So, some ion air fresheners have a function to sustain good ion balance of a room as well as a function to absorb dusts.

Statistic electricity research, standards and regulations in the U.S.:
http://www.esda.org/

At the personal level, a mobile phone is the most common devise that utilizes a radio wave. Media praises a mobile phone as a good device because it is useful at emergency such as high-jacking and contributes to settle such cases. However, a mobile phone could become a bad one if it is used carelessly disturbing others in public or utilized by criminals. It is becoming more important to educate people about the Electro-Magnetic Compatibility and technical background of radio products as well as how to use them in a good manner.

Nobuhiko Tsunefuka 1943 Born in Tokyo 1968 Graduated form Department of Engineering Science, Osaka University -1984 Worked on developing Information Technology Device at Taga Works, Hitachi, ltd. 1991- Engaged in education on EMC related matters at Hitachi Institute of Technology 1999- Planning Manager,