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Localized Surface Plasmon Resonance - an overview | ScienceDirect Topics

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In some cases, almost 100% of the light energy can be converted to the second harmonic frequency. These cases typically involve intense pulsed laser beams passing through large crystals, and careful alignment to obtain phase matching.
In other cases, like second-harmonic imaging microscopy, only a tiny fraction of the light energy is converted to the second harmonic—but this light can nevertheless be detected with the help of optical filters.
Generating the second harmonic, often called frequency doubling, is also a process in radio communication; it was developed early in the 20th century, and has been used with frequencies in the megahertz range. It is a special case of frequency multiplication.
An electron (purple) is being pushed side-to-side by a sinusoidally-oscillating force, i.e. the light's electric field. But because the electron is in an anharmonic potential energy environment (black curve), the electron motion is not sinusoidal.
The three arrows show the Fourier series of the motion: The blue arrow corresponds to ordinary (linear) susceptibility, the green arrow corresponds to second-harmonic generation, and the red arrow corresponds to optical rectification.
Electro-optic rectification (EOR), also referred to as optical rectification, is a non-linear optical process that consists of the generation of a quasi-DC polarization in a non-linear medium at the passage of an intense optical beam.
For typical intensities, optical rectification is a second-order phenomenon[1] which is based on the inverse process of the electro-optic effect.
It was reported for the first time in 1962,[2] when radiation from a ruby laser was transmitted through potassium dihydrogen phosphate (KDP) and potassium dideuterium phosphate (KDdP) crystals.
https://t.co/Px03xrubJ0

The term "electro-optic" is often erroneously used as a synonym for "optoelectronic".
Opto-electronics (or optronics) is the study and application of electronic devices and systems that source, detect and control light, usually considered a sub-field of photonics.
In this context, light often includes invisible forms of radiation such as gamma rays, X-rays, ultraviolet and infrared, in addition to visible light.
Optoelectronic devices

are electrical-to-optical

or optical-to-electrical transducers,

or instruments that use such devices in their operation.
Optoelectronics is based on the quantum mechanical effects of light on electronic materials, especially semiconductors, sometimes in the presence of electric fields.
•Photoelectric or photovoltaic effect, used in:
◦photodiodes (including solar cells)
◦phototransistors
◦photomultipliers
◦optoisolators
◦integrated optical circuit (IOC) elements
•Photoconductivity, used in:
◦photoresistors
◦photoconductive camera tubes
◦charge-coupled imaging devices
•Stimulated emission, used in:
◦injection laser diodes
◦quantum cascade lasers
•Lossev effect, or radiative recombination, used in:
◦light-emitting diodes or LED
◦OLEDs
•Photoemissivity, used in
◦photoemissive camera tube
Important applications of optoelectronics include:
•Optocoupler
•Optical fiber communications
An opto-isolator (also called an optocoupler, photocoupler, or optical isolator) is an electronic component that transfers electrical signals between two isolated circuits by using light.
https://t.co/ku83nBU7Ck

An opto-isolator contains a source (emitter) of light, almost always a near infrared light-emitting diode (LED), that converts electrical input signal into light, a closed optical channel (also called dielectrical channel),
and a photosensor, which detects incoming light and either generates electric energy directly, or modulates electric current flowing from an external power supply.
The sensor can be a photoresistor, a photodiode, a phototransistor, a silicon-controlled rectifier (SCR) or a triac. Since LEDs can sense light in addition to emitting it, construction of symmetrical, bidirectional opto-isolators is possible.
An optocoupled solid-state relay contains a photodiode opto-isolator which drives a power switch, usually a complementary pair of MOSFETs.
A slotted optical switch contains a source of light and a sensor, but its optical channel is open, allowing modulation of light by external objects obstructing the path of light or reflecting light into the sensor.
Electronic equipment and signal and power transmission lines can be subjected to voltage surges induced by lightning, electrostatic discharge, radio frequency transmissions,

switching pulses (spikes) and perturbations in power supply.
Transformers and opto-isolators are the only two classes of electronic devices that offer reinforced protection — they protect both the equipment and the human user operating this equipment.
They contain a single physical isolation barrier, but provide protection equivalent to double isolation.

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NotTheMacAnon
NotTheMacAnon
@NotTheMacAnon1
If you shine light of high enough energy on to a metal, electrons will be emitted from the metal.
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NotTheMacAnon
NotTheMacAnon
@NotTheMacAnon1
So where are we at with this virus people?
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NotTheMacAnon
@NotTheMacAnon1
This nonspecific cation channel opens when illuminated with blue light, depolarizing the cell [4, 6] to trigger action potentials cells with high temporal precision [5]. Since the initial discovery of ChR2, many modifications have been made to refine the kinetic properties.

For example, ChETA, engineered to address limitations of spike fidelity with ChR2, has faster temporal kinetics and can maintain reliable spike precision up to 200 Hz [7].

Halorhodopsins (NpHR), light-gated chloride pumps activated by yellow light, allow for temporally specific hyperpolarization with single spike precision [8–10].

Archaerhodopsin-3 (Arch), a yellow light-activated outward proton pump, is an increasingly popular tool for light-induced hyperpolarization to inhibit cellular activity. Arch recovers spontaneously from inactivation with a much shorter recovery time than NpHRs [11].

Arch currents continue to increase with increasing light intensity, while NpHRs saturate [11]. The increased light sensitivity of the ArchT variant, along with better membrane targeting, allows for improved neural silencing both at cell bodies and terminals [12].
LIFE
NotTheMacAnon
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@NotTheMacAnon1
👍🏻


https://t.co/0ywQ1y5NDj

Pott found an association between exposure to soot and a high incidence of scrotal skin cancer in chimney sweeps. This cancer is now known as Pott's or chimney sweep cancer.

Coal contains trace amounts of naturally-occurring radioactive elements. The process of burning coal at coal-fired power plants, called combustion, creates wastes that contain small amounts of naturally-occurring radioactive material (NORM).

Fly ash particles (a major component of coal ash) can become lodged in the deepest part of your lungs, where they trigger asthma, inflammation and immunological reactions.
SONG
NotTheMacAnon
NotTheMacAnon
@NotTheMacAnon1
Transduction is the process by which foreign DNA is introduced into a cell by a virus or viral vector.

Viral vectors are tools commonly used by molecular biologists to deliver genetic material into cells.

Viruses have evolved?

specialized molecular mechanisms

to efficiently

transport their genomes

inside the cells they infect.

Delivery of genes, or other genetic material, by a vector is termed transduction and the infected cells are described as transduced.

A transducer is a device that converts energy from one form to another. Usually a transducer converts a signal in one form of energy to a signal in another.
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Dr. Angela Rasmussen
Dr. Angela Rasmussen
@angie_rasmussen
Hard agree. And if this is useful, let me share something that often gets omitted (not by @kakape).

Variants always emerge, & are not good or bad, but expected. The challenge is figuring out which variants are bad, and that can't be done with sequence alone.


You can't just look at a sequence and say, "Aha! A mutation in spike. This must be more transmissible or can evade antibody neutralization." Sure, we can use computational models to try and predict the functional consequence of a given mutation, but models are often wrong.

The virus acquires mutations randomly every time it replicates. Many mutations don't change the virus at all. Others may change it in a way that have no consequences for human transmission or disease. But you can't tell just looking at sequence alone.

In order to determine the functional impact of a mutation, you need to actually do experiments. You can look at some effects in cell culture, but to address questions relating to transmission or disease, you have to use animal models.

The reason people were concerned initially about B.1.1.7 is because of epidemiological evidence showing that it rapidly became dominant in one area. More rapidly that could be explained unless it had some kind of advantage that allowed it to outcompete other circulating variants.
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Kris Postadjian
Kris Postadjian
@KrisP55
A Thread about Famous Armenian Inventors and what we have contributed to the world. So the next time someone wants to say we are unimportant, you can rest easy knowing Armenians have contributed some of the greatest inventions to mankind. Here is a handful but there's more.


Raymond Damadian: Armenian-American Physician and inventor of the first MRI machine. MRI is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. Raymond created the first MRI in 1977.


Artem Mikoyan: One of the most famous engineers in aviation. Mikoyan along with Gurevich created one of the most famous Jet lines in history, the MiG. MiG jets directly competed with American Lockheed Martin F Series planes and were among the first to surpass the speed of sound.


Hovannes Adamian: Most notably laid the foundations of color television with his Tri-Color Principle. His work would go on to become the framework that is used to create Color-TV that we see today. He is recognized as one of the founders of color television.


Emik Avakian: An inventor who unfortunately was disabled, but that didn't stop him from contributing work that would help people similar to his condition. Notable contributions are the automatic wheelchair which dismiss the action of hand rolling and a breath operated typewriter.
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Eric Holthaus
Eric Holthaus
@EricHolthaus
JUST IN: The U.S. National Climate Assessment is now public.

This is the report that the Trump Administration doesn’t want you to see. Years in the making, released on the day after Thanksgiving. #ClimateFriday

Here are some of the main

This report is mandated by Congress and focused on the impacts of climate change in the U.S.

Basically: This is what our best scientists think will happen to us as a result of the actions our government is (not) taking to address the most important problem in human history.
/2

300 experts in 13 federal agencies volunteered their time to make sure you have this information.

Please share it widely.
/3

The top finding:

“Climate change is projected to significantly affect human health, the economy, and the environment in the United

To expand on that finding:

“In the absence of more significant global mitigation efforts, climate change is projected to impose substantial damages on the U.S. economy, human health, and the environment. ...”
/5
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Asbj\xf8rn St\xf8ylen
Asbjørn Støylen
@strain_rate
1/ #LBBB generates often a classical pattern on #EchoFirst. The pattern is very distinctive in Tissue Doppler of the septum.


The classical pattern arises from the time lapse of the activation and relaxation of the two walls, creating a pattern of interaction due to a sequence temporal imbalances of the tension between the two walls.


2/ As the septum is activated first, it contracts (shortening - septal flash) without activation of the lateral wall, which stretches. This generates slower pressure build up than a normal IVC, which then is prolonged.


3/ During ejection, the LV volume decreases, so both walls shorten. Tension, however, declines first in the septum, as this was activated first. This leads to a tension imbalance, so the lateral wall continues to shorten, the more relaxed septum stretches.


4/ The stretching of the septum builds up an elastic tension in the septum, which is released as recoil, when tension declines in the lateral wall, showing a post systolic shortening in the septum which is due to elasticity.
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DR22 \u03a9 \U0001f3ad\U0001f525
DR22 Ω 🎭🔥...
@DejaRu22
Best visual demonstration of God’s source code in action
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Marc K\xf6hlbrugge
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💬 I often get Q’s like these:

How did you get your first customers for WIP? How did you grow BetaList’s traffic? Etc.

Makers are looking to reverse-engineer success. I see it everywhere.

I don’t think it works that way and the answers to those questions are mostly useless. 💥

I have built dozens of different products over the last couple of years. The vast majority failed. 😭

Surely if I know the answers to these questions, but still fail over and over again, these answers aren’t that useful. 🤷‍♀️

So what’s a better question to ask? 🤔

99.9% of the questions I receive are about the products that did well. In a way that makes sense, because we quickly forget about those that didn’t succeed.

🧠 This is known as survivorship bias.

Focusing on what survived, while ignoring what made it survive in the first place.

The real question, what you really want to know, is this:

What makes @WIP, @BetaList, and to some extent @AllStartupJobs succeed where my countless other attempts failed?

What separates a failed product 👎 from a successful product 👍?

Honestly, I don’t know. I wish I did.

It’s like Steve Jobs said “I’ll know it when I see it.” 👀

Same is true when we make products. We don’t know upfront what will work. But once we see an inkling of a product that does have potential, it’s not that hard to spot.
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Nikita Poojary
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One of the most successful stock trader with special focus on cash stocks and who has a very creative mind to look out for opportunities in dark times

Covering one of the most unique set ups: Extended moves & Reversal plays

Time for a 🧵 to learn the above from @iManasArora

What qualifies for an extended move?

30-40% move in just 5-6 days is one example of extended move

How Manas used this info to book


Post that the plight of the


Example 2: Booking profits when the stock is extended from 10WMA

10WMA =


Another hack to identify extended move in a stock:

Too many green days!

Read
SCREENERS , A SCREENER
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@oyevivekk
THREAD:

80 Films with the biggest Plot Twists that will blow your mind.

1. Fight Club


2. Predestination


3. Seven


4. Requiem for a Dream
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Pran Katariya
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The Straddle is my favorite trade these days. But more often than not, one needs to adjust to make a good return from it. There are many ways to do this depending on your view, psychology and imagination. Will discuss a few that I use

The Straddle is a delta neutral strategy and it is important to keep deltas in check during the course of the Trade and not let them run away from you. Of course Volatility is the elephant in the room- but not going there as that will require a separate discussion

The first and most common method is to go 'inverted.' That is to say to shift the untested side to generate additional Premium and increase the runway to Breakeven. So if you start with a Straddle at 700 and price goes to 740, you can move the PE up to say 720.

How much should you move the untested side? While again this is a matter of skill, experience and artistry, the rule of thumb is to cut deltas by half. Remember, prices will move and you have to allow sufficient room for them to fluctuate

The second method is to shift the entire Straddle in the direction of the move. So if you have a 700 Straddle and Price goes to 740, you can shift the Straddle to 720. If you time this right, it can generally be done at virtually no cost or minimal cost.
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\u092a\u094d\u0930\u0924\u093f\u091c\u094d\u091e
प्रतिज्ञ...
@RamaInExile
#twitterArts
Arts are best form to Express thoughts & devotion. In All civilization Arts played very important role to express sprituality. Tibbeten Tangkhas are prime example .

List of My Paintings & Sketches


प्रलय पयोधि-जले धृतवान् असि वेदम्
विहित वहित्र-चरित्रम् अखेदम्
केशव धृत-मीन-शरीर, जय जगदीश हरे!!


छलयसि विक्रमणे बलिम् अद्भुत-वामन
पद-नख-नीर-जनित-जन-पावन
केशव धृत-वामन रूप जय जगदीश हरे


नंदसि यज्ञ- विधेर् अहः श्रुति जातम्
सदय-हृदय-दर्शित-पशु-घातम्
केशव धृत-बुद्ध-शरीर जय जगदीश हरे


क्षत्रिय-रुधिर-मये जगद् -अपगत-पापम्
स्नपयसि पयसि शमित-भव-तापम्
केशव धृत-भृगुपति रूप जय जगदीश हरे
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