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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
👍🏻


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.
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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
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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NotTheMacAnon
NotTheMacAnon
@NotTheMacAnon1
So where are we at with this virus people?
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NotTheMacAnon
NotTheMacAnon
@NotTheMacAnon1
2020 marks the start of the quantum dot revolution.

Completely ignoring the fact that "photocatalytic generation of reactive oxygen species (ROS) from quantum dots (QDs) has been widely reported."

Results: It was found that whereas singlet oxygen (1O2) was not produced by photoexcited QDs, superoxide anion(O2− )and hydroxyl radicals(OH) were generated by QDs, especially in the presence of a physiological concentration of electron donating agent including NADH.

Using cell metabolic activity assays and various probes of ROS generation, the formation of ROS in cellular environments was demonstrated.

Conclusion: Illumination of QD-treated cells and bacteria with light did affect viability. The above results, together with those of assays in the presence of various scavengers of specific ROS, indicate that the formation of ROS by QDs mainly proceeded via electron transfer.
FOR LATER READ

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1) Science denial is destroying our societies, our civilization. Various vested interests, usually right wing ideologues find various scientific facts and information contrary to their agenda, so through propaganda they are orchestrating the public into denying this science.

2) We are seeing this with regard to the COVID virus, where a range of denial is being promoted, ranging from absolute denial the virus exists, to different levels of denial, such as only some people are vulnerable to the virus, to facilitate business as usual.

3) For a long time, to promote business as usual, vested interests have been promoting the denial of the climate and ecological crisis through propaganda. The aim being to create a large enough body of public denial to prevent action which can change anything.

4) We have seen similar patterns over a long time, such as when tobacco companies promoted denial of the emerging scientific evidence of how harmful and addictive tobacco smoking was. This further denial uses exactly the same methods.

5) Understandably, the public can't be educated about everything and have to rely on experts to inform them of concerns about threats to public safety. Malicious vested interests take advantage of this by using pseudo-experts to misinform the public.
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10-K Diver
10-K Diver
@10kdiver
1/

Get a cup of coffee.

In this thread, we'll cover *State Quantities* and *Flow Quantities*.

This mental model can help us analyze many different entities -- from complex engineering systems to publicly traded companies.


2/

A "State Quantity" is something that's associated with a *specific point in time*.

For example, the number of followers a Twitter account has is a state quantity. This number can go up and down over time. But at any one *specific* time point, it's fixed.

3/

Similarly, the amount of cash a company has is a state quantity.

This cash balance can also rise and fall over time.

But pick any one *specific* time point -- and the company can only have one *specific* cash balance at that time point.

4/

By contrast, a "Flow Quantity" is something that's associated with a time *interval* rather than a time *point*.

For example, the number of followers gained by a Twitter account is a flow quantity. It's meaningful only when we specify a time interval (eg, the last 30 days).

5/

A simple analogy is that a State Quantity is like a photo -- a snapshot at a particular *point* in time.

But a Flow Quantity is like a video -- a record of events that take place during a particular time *interval*.
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Corey Lynn \U0001f64f\U0001f1fa\U0001f1f8
Corey Lynn 🙏🇺🇸...
@CoreysDigs
1) OBSERVATION: The frequencies are changing. I would have to assess stats on the electromagnetic field to see its fluctuations. All I know is, I am highly sensitive to energy/frequencies, and they are changing, because…

2) 2 Weeks ago, my dog was effected by it as well. He is hearing things that aren’t technically audible. I can tell by his body language and sounds. One week ago I began feeling a pressure in my head and ears. It wasn’t painful at all, but it was intense for a bit.

3) It reminded me of taking off in an airplane a bit. I felt like I was in a vacuum. It went on and off for a couple of days. I’ve picked up on frequencies and high pitched sounds (not audible to most) for 30 years, and today my right ear began to ring for longer than usual.

4) This is nothing unusual for me, with exception of the duration. This happens often with me. No, it’s not tinnitus. Only this time, when I spoke, there was reverb creating a high pitch in my ear from my voice. This lasted for about 30 minutes. It did not hurt, just annoying.

5) So yes, the frequencies are changing. What this means exactly, I am unsure of at the moment. Some will say electromagnetic fields, others will say ascension, and some will say pole shift. I honestly can’t say at this very moment.
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Yardley Yeadon
Yardley Yeadon
@MichaelYeadon3
In a number of Sunday papers:
Scientific advisers said it was “hard to see” when the restrictions would end as new variants continued to emerge, delivering a potentially devastating blow to the travel industry. The prime minister said that after progress with vaccinations...

...”what we don’t want to see is all that work undone by the arrival of a new variant that is vaccine-busting”.
The idea is planted in people’s mind that this virus is mutating in such a way as to evade prior immunity. This is completely unfounded, certainly as regards immunity..

...gained naturally, after repelling the virus (which well around 99.9% of the population do, fewer, obviously in the very elderly & already ill, more in those younger & well). It’s important to appreciate that upon infection, the human immune system cuts up an infectious...

...agent into short pieces. Each of these short pieces of protein are presented to other cells in the immune system, like an identity parade. Our cells have a truly astonishing range of abilities to recognise different protein structures, and there will be some which recognise...

...each of the pieces of the invader. The cells which recognise a piece are instructed to multiply selectively so that, after a few days to a couple of weeks, our bodies contain large numbers of virus piece specific cells. These have a range of functions. Some make antibodies...
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Jambavan
Jambavan
@SirJambavan
https://t.co/odzm9VTdwZ

Thread for today. /0

It is fashionable for people to create sympathy to the unseen / unknown organisms. The poor things that can't stand up and fight for their own existence.

It makes for a brilliant narrative. It melts your hearts. And you get to play saviour of the oppressed by outraging. /1

But, for most part, such things are also false.

Amazon are the lungs of the world. Never mind that most of the world's oxygen production happens in open oceans. But these are harmless ones. Of course, we all love to maintain forests.

However, some things are sheer scare mongering.

For instance - take this: coral reefs will be permanently gone if mean / median temperatures raise by 1°C ..

But, really - how? Then you get a lecture on how CO2 will affect calcification.

Dig a bit deeper from another angle+

+ and you find that the earth was much much warmer during the age of Dinosaurs. So much so, that we had cold blooded lizards growing to sizes of buildings. Surely, there must have been tons of CO2 then!

And the ocean temps were quite high too.
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Mr. Vijay Kedia built a net worth of over Rs. 800 crores.

But you probably never read past that headline.

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Here are 20 lessons on investing from @VijayKedia1 Sir:

Collaborated with @AdityaTodmal


Before I start, a quick disclaimer, please don't ape his portfolio.

As the entry price, horizon and risk appetite would be far different than yours.

Rather lets draw inspiration and try to learn his stock picking skills.

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1/ Started off as a trader:

- Soon, beginner’s luck started to fade out and loses started to mount, to an extent where his mother was about to sell her ornaments.

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Antonio Garc\xeda Mart\xednez
Antonio García Martíne...
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Ok, I'll hop on this Elizabeth Warren/Native American testing bandwagon (gently and non-politically).

I've been a @23andMe customer for a while, and have followed their ancestry updates closely.

All is more or less as expected....except for this bit about Native American.


The family is almost completely composed of Spanish peasants (from various regions) who emigrated, along with a massive wave in the late 19th-cent./early 20th-cent., to Cuba back when it was a booming economy (richer than Spain's) and worth emigrating to (Communism killed that).

Also, the native population of Cuba was annihilated early on---was the first place the Spanish colonized after all. Having a native background in Cuba would be like having the same in, say, Massachusetts, particularly if you're (say) mostly Irish. Just really, really unlikely.

(Note: the North African/Arab background is less mysterious. The Iberian peninsula was part of the Muslim world for centuries. It would be odd *not* to have some Arab/Middle Eastern background coming from Spain. Given the family is mostly from Northern Spain, it's small though.)

I have a Spanish passport, have been back to the ancestral villages in Spain, seen the church where my grandmother was baptized, my grandfather told me stories about growing up as the child of Spanish colonists in rural Cuba. The native bit just clashes with all the family lore.
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Sri Sanjeevi Rayar Temple located in Ayyangar Kulam,near Kanchipuram,TN

#Thread

Ancient but beautiful temple dedicated to Hanuman. This temple is a legendary one. According to the Sthala Puranam of Sanjeevi Rayar temple,it is associated with an episode from Ramayana.


Legend story -Hanuman was flying from Himalayas to Lanka bearing Sanjeevi hill to revive Lakshmana during battle between Rama& Ravana, a piece of the Sanjeevi Parvat fell at this place.Many believe this legendary story & even today that no one here dies of any kind of poisoning.

From historical background of the temple it is known that temple was originally built by a great scholar &administrator Kotikanyadanam Lakshmikumara Tatacharya. Temple itself&village were named following name of great scholar Tatacharya, who was then popularly known as Ayyangar.

He was the royal preceptor of Vijayanagara emperor Venkata Raya who had his capital at Chandragiri in AP.Upon returning from a pilgrimage,robbers tried to attack Tatacharya at this place. Being a great devotee of Hanuman,he instantly composed a poem in Sanskrit praising Hanuman.


The bandits immediately ran away &Tatacharya decided to build a temple dedicated to Anjaneya at that very place.This Sanskrit poem is called Hanumad Vimshati, has been inscribed in Grantha script inside this temple.The huge temple tank called Tatasamudram, in honor of Tatacharya.
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Bharadwaj
Bharadwaj
@BharadwajSpeaks
Hinduism is a minority religion in Punjab.

During the Khalistan movement, the minority Hindus and Jains were subjected to several attacks. Hindu and Jain temples were frequently vandalized and desecrated. This thread documents a few instances.

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Durgiana Mandir is one of the oldest temples of Amritsar. According to the regional Hindu tradition, the temple was built on the spot where Lava and Kusha bound Hanuman. The temple annually attracts millions of Hindus from all over the country.


Amristsar has a very ancient Hindu history.

According to the regional Hindu tradition recorded in the "Survey of Amritsar", Amritsar got its name from Amrit immersed by Lava and Kusha in a pond.


Durgiana Mandir was rebuilt in 1921.

It was used to house the Murtis of Vishnu and Durga which were thrown out from the Parikrama of Harmandir Sahib in 1905.

Because of its presence in Amritsar, it became a frequent target of radicals during the Khalistan movement.


In 1982, in what was a completely unprovoked attack, the Dal Khalsa "activists" threw a severed cow head inside Durgiana temple.
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