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Popular science

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How does a barcode work?

Reading time6 min
Views13K
Hi all!

Every person is using barcodes nowadays, mostly without noticing this. When we are buying the groceries in the store, their identifiers are getting from barcodes. Its also the same with goods in the warehouses, postal parcels and so on. But not so many people actually know, how it works.

What is 'inside' the barcode, and what is encoded on this image?



Lets figure it out, and also lets write our own bar decoder.
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Hell or high water: history of Russian popular science literature

Reading time9 min
Views3.1K
And our homeland's pushing us For reaching knowledge higher heights.

The available and interesting literature on science is a magic wand that helps the progress not to slow down and move forward. Thanks to interesting science literature, children begin to study voluntarily and with interest, while adults expand their horizons and do not allow the brain to relax. Biology, astronomy and mathematics supplant the saga about the elves and intergalactic ships. But while Western countries' nonfiction was always in smooth progress from Jules Verne to Eliezer S. Yudkowsky, then opposite it experienced both ups and downs in Russia.
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Researchers from MIT designed «rectenna» which converts Wi-Fi signals into electricity

Reading time2 min
Views3K

Source: eeNews Europe

I'm glad that Habr got brand new English version. And my first post in English is about new MIT project. Researchers designed an ultra-low capacitance and ultra-low resistance Schottky diode capable of switching at GHz frequencies. This diode is able rectify and convert random WiFi signals into DC electricity.

MoS2 «rectenna» (this is how scientists called their invention) could become the main element of roll-to-roll process to cover a huge areas. To be fair antennas capable transform radio signals in to electricity is not a new thing. The main achievement of MIT engineers is creation of soft rectenna made from special alloy.
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Most common misconceptions in popular physics

Reading time5 min
Views3.4K
Somewhere in an alternative Universe, based on MWI, I became a genius in physics. But in our Universe, I just read professional publications in physics, trying to keep myself up to date, meanwhile working as pizza delivery guy as DBA. Because of a slightly deeper knowledge of the subject it is almost impossible for me to watch the Discovery channel and other popular TV shows and the YouTube videos. I see nothing but oversimplifications, lies, and half-truths and can’t enjoy the shows.

I decided to compile a list of the most popular misconceptions. And the winner is...., or course, this one:

The Big Bang


Usually it is pictured like this:

image
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Common misconceptions about space-grade integrated circuits

Reading time27 min
Views22K

Space exploration was always fascinating, and recent developments have reignited the interest to the heights never seen since the last man stood on the Moon. People argue about Mars exploration and features of spaceships as their grandparents would’ve done if the internet existed fifty years ago. I’m an electronics engineer working in the aerospace industry, so I know a thing or two about the technical background of this stuff — and I see that these things aren’t common knowledge, and people often have significantly skewed ideas about the reasons behind many things and decisions. Namely, I’d love to speak of some misconceptions about radiation hardened integrated circuits and the means of protection from radiation-induced damage.

So, let's start our journey

Weekend Picks: light reading for STEM majors

Reading time4 min
Views1.5K
The weekend is upon us, and so is the paralysis that comes with having nothing to do. Fear not, our editorial team picked 9 books on science and tech worth picking up on a cold winter day. You’ll learn about the history of space exploration, join a physicist on a surprisingly science-appropriate hike, and more.

Flightradar24 — how does it work? Part 2, ADS-B protocol

Reading time9 min
Views8.1K
I’m going to have a guess and say that everyone whose friends or family have ever flown on a plane, have used Flightradar24 — a free and convenient service for tracking flights in real time.

image

In the first part the basic ideas of operation were described. Now let's go further and figure out, what data is exactly transmitting and receiving between the aircraft and a ground station. We'll also decode this data using Python.
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Finally, rejuvenation is a thing

Reading time6 min
Views3.3K

Preface


What is ageing? We can define ageing as a process of accumulation of the damage which is just a side-effect of normal metabolism. While researchers still poorly understand how metabolic processes cause damage accumulation, and how accumulated damage causes pathology, the damage itself – the structural difference between old tissue and young tissue – is categorized and understood pretty well. By repairing damage and restoring the previous undamaged – young – state of an organism, we can really rejuvenate it! It sounds very promising, and so it is. And for some types of damage (for example, for senescent cells) it is already proved to work!

Today in our virtual studio, somewhere between cold, rainy Saint-Petersburg and warm, sunny Mountain View, we meet Aubrey de Grey, again! For those of you who are not familiar with him, here is a brief introduction.
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Artificial neural networks explained in simple words

Reading time7 min
Views4.7K
image

When I used to start a conversation about neural networks over a bottle of beer, people were casting glances at me of what seemed to be fear; they grew sad, sometimes with their eyelid twitching. In rare cases, they were even eager to take refuge under the table. Why? These networks are simple and instinctive, actually. Yes, believe me, they are! Just let me prove this is true!


Suppose there are two things I’m aware of about the girl: she looks pretty to my taste or not, and I have lots to talk about with her or I haven’t. True and false will be one and zero respectively. We’ll take similar principle for appearance. The question is: “What girl I’ll fall in love with, and why?”


We also can think it straight and uncompromisingly: “If she looks pretty and there’s plenty to talk about, then I will fall in love. If neither is true, then I quit”.


But what if I like the lady but there’s nothing to talk about with her? Or vice versa?

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Cosmonaut Aleksandr Laveykin about the best space movie, G-force of 20g, and soft landing

Reading time6 min
Views1.7K
Three years ago, ASCON, the parent company of C3D Labs, invited cosmonaut and Hero of the Soviet Union Aleksandr Laveykin to its Partnership Conference. As a guest speaker, he told the audience of Russian IT companies about his 174-day spaceflight and answered questions posed by conference attendees.

Up to now, the Q&A had not been translated into English. We post them for upcoming International Day of Human Space Flight (or Cosmonautics Day in Russia).

Aleksandr Laveykin flew to space in 1987 and worked as a flight engineer on board the Mir Space Station, orbiting the Earth for six months. He completed three spacewalks lasting a total of eight hours and 48 minutes.

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Image: TASS

Stonehenge. The secrets of megaliths

Reading time2 min
Views1.2K
A version how people transported megaliths in Stonehenge.

image

They started their work in summer.

They prepared road for transportation. They needed a clean and glade road without stones and other irregularities. (No.4 on picture)
Perhaps they cut the topsoil and covered the road with clay. (No.3 on the picture)
On each side they made curbs ( 5-10 cm). (No.2 on the picture)
They used clay because they wanted to hold water inside the road.
In autumn rains filled road with water. It looked like a big puddle. (No.5 on the picture)

In winter road froze. Then they got a smooth ice skating rink slightly wider than a megalith.

Megaliths (No.11) were transported in winter.

Mechanism and vehicles for transportation were prepared in summer.

Mechanism consisted of three parts.

image
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Langton's ant: a mystery cellular automaton

Reading time4 min
Views3.2K

The life of Langton's Ant seems sad and lonely, but, as we'll soon discover, he is not ready to put up with such an outrageous situation and is trying his best to escape. American scientist Christopher Langton invented his ant back in 1986. Since then, no one has been able to explain the strange behavior of this mysterious model...

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What is to see under the Black Sun of Giedi Prime?

Level of difficultyEasy
Reading time6 min
Views2.4K

The director Denis Villeneuve and cinematographer Greig Fraser in their Dune: Part Two movie made a curious decision to film the scenes on the surface of the Giedi Prime planet in the infrared spectrum. It turned out to have interesting aesthetics and there are some interesting related physics to discuss and speculate about how realistic the look of it is.

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The Collatz conjecture is the greatest math trick of all time

Reading time4 min
Views3.8K

On the Internet and in non-fiction literature you can often find various mathematical tricks. The Collatz conjecture leaves all such tricks behind. At first glance, it may seem like some kind of a trick with a catch. However, there is no catch. You think of a number and repeat one of two arithmetic operations for it several times. Surprisingly, the result of these actions will always be the same. Or, may be not always?

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Modern X-ray detectors

Level of difficultyMedium
Reading time11 min
Views4K

Wilhelm Röntgen discovered X-ray November 8th 1895, when he did experiments with cathode rays in a vacuum tube. To capture and save images of the shadows from the X-rays, he used ordinary photoplates. Fortunately, sensitive to visible light silver based photoemulsions turned out to be sensitive to the X-ray too. These photoplates became the first X-ray detectors.

More than 100 years of scientific progress led to the creation of a number of various detectors for recording X-ray images. Developments of the microelectronics and semiconductor manufacturing technologies are crucial for development of the modern X-ray detectors. These detectors can transform the energy of the X-ray photon directly to the electrical signal. They allow capturing detailed, digital, high-resolution X-ray images.

Digital images are easy to work with. For example one can merge multiple macro images into an image of the whole object and represent monochrome images in false colors like Simon Procz did with this X-ray image of a flower he did in 2012.

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Research in rejuvenation biotechnology – where are we now?

Reading time2 min
Views1.5K


Certainly this event is an example of some of the people in our longevity community coming in and just taking over a little bit of somebody else's conference to talk about longevity… but really exposing the rest of the community to it. I'm finding that at every event I go to, I'd really love to have conference presentations where I get to talk about some interesting thing about the longevity industry, because there are a lot of really interesting things going on.

But every presentation turns out to be «hey, we exist, please notice us — because this is really, really important.» Everything that you guys think that you are doing in medicine is about to be up-ended, because suddenly we're going to be actually able to stop people from getting sick and incapacitated and debilitated in old age. This is happening right now, the first rejuvenation therapies exist. But nobody notices.
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Koans as Ontological Formulas

Level of difficultyHard
Reading time8 min
Views1.7K

If you meet the Buddha, kill the Buddha. Notes on the Forgotten Nature of Zen Koans

I don’t know how koans were perceived when they sounded like thunder. Perhaps not at all as they are analyzed by modern philosophers. Perhaps koans were not analyzed, but lived. And it is impossible to transmit a lived experience across centuries. It is an individual experience. Well then, perhaps we have lost the essence of koans. Or perhaps we never knew it. In that case, I can very well allow myself to present koans as I see them.

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Intelligent systems at phystech: 2025 graduation

Reading time14 min
Views1.1K

The students of the Intelligent Systems Department successfully defended their bachelor’s and master’s theses. This year, 14 Bachelor’s and 8 Master’s students earned their degrees in Physics, Mathematics, and Computer Sciences. We are proud to say that our Department is unique in publishing the complete set of defense materials during the last ten years. These materials include the text of the dissertation work, the published papers, the code of the computational experiments, and the slides with video of the defense talk.

In this post, we gladly summarize the defended works of our BS and MS students and highlight the results. A recording of their pre-defence presentations can be found here and here in Russian. Most part of the theses has a publicly available English version. 

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