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2025-01-28 Update From: SLTechnology News&Howtos shulou NAV: SLTechnology News&Howtos > IT Information >
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Shulou(Shulou.com)11/24 Report--
The original title: "the strange thieves hiding around us unwittingly" stole "our" private information "? "
Lately
The editor found out
There was a strange thief dressed in white around him.
With a white pistol.
Aim at us.
Pull the trigger.
And then our private information
It was "stolen"
What kind of flying bandit is this?
Haven't touched me yet.
So you stole my private information, my body temperature?
Hey, hey.
Just let me Litchi Jelly Conan.
To solve the whole process of his crime.
Motive: the origin of the thermometer before the advent of the thermometer, people already knew that there was some internal relationship between fever and disease, but due to technical limitations, people can only feel the change of body temperature by touching the forehead, cheeks and other areas with their hands. Friends should have used this ancient method of temperature measurement when they had a fever.
In 1593 Galileo Galilei, an Italian physicist, carried out a study: take a connected glass tube with an opening at one end and a hollow glass bubble at the other end, pour some water into the tube and reverse it, lowering the opening into another container that also contains water. When the temperature of the glass ball increases, the internal gas expands and the height h of the liquid level decreases; when the temperature of the glass ball decreases, the internal gas contracts and the height h of the liquid level increases. If the scale is marked on the glass tube, the change of temperature can be reflected to a certain extent. As the water container is connected with the external atmosphere, the temperature measurement will be affected by environmental factors such as atmospheric pressure, and the error is large and not accurate enough.
Schematic diagram of Galileo device and physical diagram Italian doctor Santorio Santorio found that the sweating phenomenon of the human body is related to illness and temperature, so he improved Galileo's thermometer and marked it with a scale. But the model is bulky and impractical, and it takes quite a long time to accurately measure the patient's temperature.
In 1654, Archduke Ferdinando II (Ferdinand II) of Tuscany made the world's first alcohol thermometer. He experimented with a variety of liquids and found that the volume of alcohol changed significantly after heating, so he injected alcohol into a glass ball with a glass tube at one end, heated the glass ball, made the alcohol volatilize and discharged air from the tube, and finally sealed the glass tube. His improvement to the thermometer eliminated the effect of atmospheric pressure, but because the boiling point of alcohol was low, it was impossible to measure the temperature of boiling water.
In 1714, Gabriel Daniel Fahrenheit, a German physicist, began to study the properties of hot expansion and cold contraction of liquids. He found that mercury expanded and contracted more violently than alcohol, so he poured mercury into the thermometer and made the first mercury thermometer.
By the mid-19th century, the transportation and use of thermometers were still troublesome. Medical thermometers were still one foot long (30.28 centimeters) and took up to 20 minutes to measure accurate temperature readings. Between 1866 and 1867, Sir Thomas Clifford Albute (Thomas Clifford Allbutt) designed a medical thermometer that was more portable, only six inches long and could record a patient's temperature in five minutes.
Means of committing a crime: the formation of the temperature scale is analyzed from the perspective of the feasibility of "committing a crime". Accurate measurement must be an important means of "stealing" body temperature information.
In 1724, Gabriel Wallenheit mixed water, ice and ammonium chloride, reached the lowest temperature that could be recorded at that time, and set it at 0 degrees, based on which the temperature of the ice-water mixture was determined to be 32 degrees Celsius. Because the boiling point of alcohol is low, can not bear the temperature of boiling water, so after the introduction of mercury thermometer, the boiling point of water at atmospheric pressure was 212 degrees. He placed the thermometer in his mouth or under his armpit and determined that the body temperature was 96 degrees. This is the first precisely calibrated thermometer in history, and he named it after himself, the Fahrenheit scale-in ℉.
In 1742, Swedish astronomer Anders Celsius Sears (Anders Celsius) invented another percentile temperature scale: the boiling point of water at an atmospheric pressure is set at 0 degrees, and the mixture of ice and water is set at 100 degrees. Later, in order to make it easy to use, Carolus Linnaeus turned it upside down and formed the current temperature scale. In 1948, in honor of Celsius, it was stipulated at an international conference on measurement that the percentile temperature scale was called the Celsius scale-in ℃.
The conversion relationship between Fahrenheit scale (F) and Celsius scale (C) is as follows:
Tracking down "suspects": modern thermometers next, we analyze several suspicious "suspects" and identify "prisoners" through exclusion.
Mercury thermometer when it comes to thermometer, what we are most familiar with is mercury thermometer, which is the same as Warren Haight's first mercury thermometer, which uses the principle of mercury thermal expansion and cold contraction to measure the temperature. But the modern thermometer is more convenient to use and has more reliable performance.
Mercury is stored in the glass bubble at the end. When the temperature of the glass bubble is measured by a thermometer, the mercury expands into the thin glass tube when the temperature of the glass bubble rises, and the temperature change is indicated by the scale at the end of the mercury column.
The mercury thermometer has a very narrow necking near the glass bubble in the lower part of the thermometer. When the thermometer leaves the body, the mercury cools and contracts. Because the mercury does not infiltrate on the glass, and the local contraction of the mercury is faster than the flow of the liquid at the contraction (the contracted mercury does not have time to flow back into the glass bubble), the mercury column will be "disconnected" at the shrinkage. So that the mercury in the tube can not return to the glass bubble for stable reading. So shake the mercury column back into the glass bubble before using the thermometer every time.
Mercury thermometer structure diagram; source: reference 2 considering that the mercury thermometer needs to be measured under the armpit, which is not consistent with the modus operandi, rule out the suspect!
Thermistor thermometer in 1821, David of England discovered that metal resistance changes with temperature. The metal conducts electricity through the outer free electrons. with the increase of temperature, the thermal motion of the free electrons increases, the collision probability with the atomic solid increases, and the resistance increases.
Metal Conductive schematic in 1833, Michael Micheal Faraday invented the first NTC thermistor. He discovered the semiconductor behavior of silver sulphide.
Semiconductors conduct electricity by using conduction band electrons and valence band holes as carriers, and the conduction band electrons transition to the valence band, resulting in a conduction band electron and a valence band hole. With the increase of temperature, the probability of this transition increases, the number of carriers increases, and the resistance decreases near the body temperature (weak collision caused by thermal motion).
Semiconductor energy band diagram the resistance thermometer we use now is sensed by NTC thermistor, which is a semiconductor ceramic made by fully mixing, forming and sintering two or more metal oxides such as manganese, copper, silicon, cobalt, iron, nickel, zinc and so on. it has the conductive properties of semiconductors, and the resistance decreases with the increase of temperature. Body temperature information can be obtained through the precise relationship between resistance and temperature.
NTC resistance curve with temperature change curve this thermometer through integrated circuit data analysis, and the modus operandi are similar, but also need to contact the body to obtain body temperature, the degree of suspicion is not high enough.
Infrared thermometer the last suspect is an infrared thermometer. The editor guessed: when pulling the "trigger", the temperature measuring gun must have emitted some kind of advanced signal to "steal" our temperature information. Did not expect his clever means, did not leave any trace, I litchi jelly Conan is also helpless. Just when the editor was helpless, he suddenly saw what was on the table.
After opening it, the thief really gave himself away.
Any object with a temperature higher than 0 K (about-273.15 ℃) will radiate electromagnetic waves outward. In physics, an ideal model-blackbody (an object that completely absorbs external radiation of any wavelength without any reflection) is used to describe this radiation phenomenon. The outward radiation of this object is only related to temperature.
Blackbody radiation law; Source: Ref. 9 everyone's body temperature must be above 0K, it is this bug that makes the infrared thermometer take advantage of the loophole. Its built-in sensor can detect the infrared electromagnetic wave radiated by our body. because the infrared energy and wavelength distribution are only related to the temperature, the body temperature information can be obtained by calculating this fixed law.
Schematic diagram of the principle of the temperature measuring gun; source: 9 refs. So the infrared thermometer does not transmit signals, but receives signals.
What you think is taking the temperature:
The actual temperature is taken:
I didn't think of that.
The "prisoner" turned out to be ourselves.
Is that we constantly radiate our body temperature information.
I really misunderstood the thermometer.
So
During the epidemic period
Friends should cooperate with the prevention and control of the thermometer!
reference
Wang Binquan, Zhao Xiaoyun. The invention and development of thermometer [J]. Nursing Research, 2007, 21 (5): 469,469.
Huang Sihan, Lu Zhe, Yang Hui. Study on the principle of swinging reset of mercury thermometer [J]. Contemporary Teaching and Research Series, 2020 (11): 1.
[3] Resistance thermometer-Wikipedia
[4] Thermistor-Wikipedia
[5] Medical thermistor-Wikipedia
[6] Electronic thermometer Baidu Encyclopedia (baidu.com)
[7] A brief history of body temperature (smxz.com.cn)
[8] physiological 43 "Fahrenheit" temperature-- Warren Haight and the establishment of "Fahrenheit temperature scale"-zhihu.com)
[9] what is the working principle of laser infrared thermometer? -zhihu.com
[10] does the resistivity of metallic materials increase with the increase of temperature? -zhihu.com
This article comes from the official account of Wechat: Institute of Physics, Chinese Academy of Sciences (ID:cas-iop), author: litchi jelly
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