Physics
868 views | +0 today
Follow
Your new post is loading...
Your new post is loading...
Scooped by Mikko Hakala
Scoop.it!

NASA rover's images show laser flash on martian rock (w/ Video)

NASA rover's images show laser flash on martian rock (w/ Video) | Physics | Scoop.it
(Phys.org) —Flashes appear on a baseball-size Martian rock in a series of images taken Saturday, July 12 by the Mars Hand Lens Imager (MAHLI) camera on the arm of NASA's Curiosity Mars Rover. The flashes occurred while the rover's Chemistry and Camera (ChemCam) instrument fired multiple laser shots ...
Mikko Hakala's insight:

Spectrosccopic analysis of the Martian rocks after laser shots. 

 

More info:

http://phys.org/news/2013-12-martian-laser-surpasses-zaps.html

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

The Little-Known Scientific Reason Your iPhone Earbuds Always Get Tangled

The Little-Known Scientific Reason Your iPhone Earbuds Always Get Tangled | Physics | Scoop.it
Knots really do form on their own as a matter of physics, not because of your personal lack of neatness.
Mikko Hakala's insight:

A perfect everyday physics article - Must read. 

 

Via @DoTryThisAtHome

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Ionic liquid boosts efficiency of CO2 reduction catalyst

Ionic liquid boosts efficiency of CO2 reduction catalyst | Physics | Scoop.it
(Phys.org) —Wouldn't it be nice to use solar- or wind-generated electricity to turn excess carbon dioxide—one of the gases trapping heat in Earth's atmosphere—into fuels and other useful chemicals? The process would store up the intermittent solar or wind energy in a form that could be used when ...
Mikko Hakala's insight:

How to reduce excess CO2 in the atmosphere? CO2 is one of the culprits for the greenhouse effect.

 

The research described in this Phys.org article used ionic liquid as a reaction medium for CO2 and the catalyst. The purpose is to reduce CO2 to CO, which can be further converted to more useful forms. The setup with ionic liquids was found to be better for the speed of the reaction and energy efficiency. Ionic liquids themselves are novel, tailorable liquids, and have promise to replace traditional solvents.

 

The work shows that there is progress in efforts for CO2 reduction, but apparently rather slowly. The basic fundamental research could play here a key role: The 'unknown' in the whole process is that one doesn't know exactly how the chemical reaction happens. That means that one doesn't know clearly what to modify in the process to make it happen easier (that is, how to lower the activation barrier for the reaction).

 

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Free Educational Physics Lecture Videos with Lecture Notes

Free Educational Physics Lecture Videos with Lecture Notes | Physics | Scoop.it
After teaching physics in a high school classroom for 13 years, I stepped out of the classroom to start Flipping Physics, a business dedicated to creating free, clear, concise and comedic physics educational videos.
Mikko Hakala's insight:

A nice and fun set of physics lecture videos. Many topics are covered, for example mechanics, electromagnetism, electrical circuits, refraction, interference. Some lectures also on modern physics.

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

High-Tc superconductors: key similarities and differences between electron- and hole-doped cuprates unveiled by X-rays

High-Tc superconductors: key similarities and differences between electron- and hole-doped cuprates unveiled by X-rays | Physics | Scoop.it
Mikko Hakala's insight:

Experimental studies for the spin and charge excitations in doped cuprates. Insight into the energy - wavevector relation of the excitations is important since spin fluctuations are connected to the superconductivity in cuprates. These high-resolution resonant inelastic X-ray studies are an alternative to neutron scattering to investigate spin dynamics.

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Scientists discover new magnetic phase in iron-based superconductors

Scientists discover new magnetic phase in iron-based superconductors | Physics | Scoop.it
(Phys.org) —Scientists at the U.S. Department of Energy's Argonne National Laboratory have discovered a previously unknown phase in a class of superconductors called iron arsenides. This sheds light on a debate over the interactions between atoms and electrons that are responsible for their unusual ...
Mikko Hakala's insight:

More research on iron-based superconductors (http://sco.lt/7CfptR), here on doped barium iron arsenide. The electron pairing mechanism is not understood in these unconventional superconductors. To elucidate the mechanism, one issue is to map out the precise phase diagrams.


Here neutron diffraction showed that on lowering the temperature, close to the onset of superconductivity, the structure restores 4-fold symmetry. At higher temperatures the structure has nematic ("thread-like") order with 2-fold symmetry, whereas at room temperature the symmetry is again 4-fold.


The finding appears to support the model that the nematic phase is driven by magnetic interactions and not by iron 3d orbital ordering. And this hints, according to the phys.org article, that it could be magnetism that could be the key to electron pairing. 


Pin it for later:

http://www.pinterest.com/pin/318981586080372229/


The Nature Communications article:

http://www.nature.com/ncomms/2014/140522/ncomms4845/full/ncomms4845.html


more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Solution to two long-standing mysteries of cuprate superconductivity found

Solution to two long-standing mysteries of cuprate superconductivity found | Physics | Scoop.it
Scientists seeking to understand the intricacies of high-temperature superconductivity—the ability of certain materials to carry electrical current with no energy loss—have been particularly puzzled by a mysterious phase that emerges as charge carriers are added that appears to compete with superconductivity. ...
Mikko Hakala's insight:

More on the superconductivity of cuprates (see http://sco.lt/5pcQjZ).

 

At low hole doping, i.e. at the pseudogap phase, the static electron arrangement (charge density wave or "frozen" stripe patterns) and the associated nanoscale fluctuations prevent the free flow of electrons. At higher hole doping the density wave disappears and unrestricted superconductivity appears.

 

Measurements by spectroscopic imaging scanning tunneling microscope.

 

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Scientists find X-rays can cause reversible resistance changes

Scientists find X-rays can cause reversible resistance changes | Physics | Scoop.it
(Phys.org) —Usually, when we think of a device that has defects, it means it's time to throw it out. However, for several types of materials, imperfections are what actually make them function in the first place. Finding ways to control defects in a material without irrevocably damaging it could yield ...
Mikko Hakala's insight:

In addition to X-rays being a great diagnostic tool for microscopic and long-range atomic and electronic structures, this study says they can also trigger controlled resistive switching in TiO2 (that is, changes in electrical resistance) by orders of magnitude.    

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Physicists discover how to change the crystal structure of graphene

Physicists discover how to change the crystal structure of graphene | Physics | Scoop.it
A University of Arizona-led team of physicists has discovered how to change the crystal structure of graphene, more commonly known as pencil lead, with an electric field, an important step toward the possible use of graphene in microprocessors that would be smaller and faster than current, silicon-based ...
Mikko Hakala's insight:

The paper shows that the stacking of graphene layers (in a 3-layer case) can be controlled with an external voltage. This way one obtains either metallic or semiconducting behavior. According to the article, for the first time such on-off switch is demonstrated in graphene.

 

This is in early stages but could become very important if the tuning of graphene's electrical properties can be realized at larger scale. The ultimate aim is a graphene-based transistor, with huge advantages compared to silicon-based ones.

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Phase transiting to a new quantum universe

Phase transiting to a new quantum universe | Physics | Scoop.it
(Phys.org) —Recent insight and discovery of a new class of quantum transition opens the way for a whole new subfield of materials physics and quantum technologies.
Mikko Hakala's insight:

This phys.org article gives a flavor of the intriguing condensed matter physics related to ferroelectric materials and their quantum phase transitions (QPT) to paraelectric ones. In QPTs, the order-disorder transition takes place at absolute zero temperature, and is achieved by chemical or isotope substitution, or by doping.

 

In this work it was found that for ferroelectrics the physics describing the phase transition is very different from the better know ferromagnetic counterparts. In fact, "the fluctuation spectrum found in quantum critical ferroelectrics is the same as that in elementary particle physics—propagating modes in three spatial dimensions plus one time dimension."

 

Wikipedia article on quantum phase transitions:

http://en.wikipedia.org/wiki/Quantum_phase_transition

 

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Solar-cell materials and efficiencies

Solar-cell materials and efficiencies | Physics | Scoop.it

What are the types and efficiencies of current phovoltaic materials? This Wikimedia Commons graph is a great, constantly updated reference to various photovoltaic technologies under research. The classification is to following types of cells:

 

1) multijunction

2) single-junction GaAs

3) crystalline Si

4) thin-film (CIGS, CdTe, amorphous and other forms of Si )

5) emerging (perovskite, quantum dot, organic, inorganic, dye-sensitized)

Follow it to stay updated on recent achievements.

 

More information:

 

* Nature Photonics has a focus issue on a set of cutting-edge solar cell technologies. It covers quantum dot, polymer, dye-sensitized and intermediate-band solar cells: http://www.nature.com/nphoton/focus/photovoltaics/index.html

The editorial 'A sunny outlook': http://www.nature.com/nphoton/journal/v6/n3/full/nphoton.2012.38.html

 * Brief info on CdTe: http://spectrum.ieee.org/nanoclast/green-tech/solar/what-makes-for-better-cdte-solar-cells  Figure: By NREL (US Department of Energy) [Public domain], via Wikimedia Commons

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Impurity size affects performance of emerging superconductive material

Impurity size affects performance of emerging superconductive material | Physics | Scoop.it
Research from North Carolina State University finds that impurities can hurt performance – or possibly provide benefits – in a key superconductive material that is expected to find use in a host of applications, including future particle colliders.
Mikko Hakala's insight:
Role of defects in the high critical temperature superconductor material bismuth strontium calsium copper oxide Bi2212 discussed. This is a promising material for superconducting wires. Small-sized defects act as beneficial pinning centers for the magnetic vortices, thus preventing resistance build up when magnetic fields are present.
more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Throwback Thursday: Top 5 Signs of New Physics

Throwback Thursday: Top 5 Signs of New Physics | Physics | Scoop.it
The Standard Model can’t be all there is. Here are five compelling reasons why.
Mikko Hakala's insight:

What lies beyond the Standard Model? If you want to get a nice summary of the current state of the art, read this quality article. From dark matter to baryogenesis, the article discusses 5 exciting clues.

more...
No comment yet.
Rescooped by Mikko Hakala from Nuclear Physics
Scoop.it!

Upgrade for European light source

Upgrade for European light source | Physics | Scoop.it

European Synchrotron Radiation Facility (ESRF). One of Europe's premier scientific research laboratories is to go through a major upgrade.


Via Theo J. Mertzimekis
Mikko Hakala's insight:

 

European Synchrotron Radiation Facility (ESRF) is a most powerful X-ray machine in Europe, supported and shared by 20 countries. See http://www.esrf.eu/ ;

 

ESRF is going through a major upgrade. This BBC article by @BBCAmos (via @tmertzi) tells some essential information what this means to ESRF. See how much more radiation will be obtained, how much will the upgrade cost and the timetables.

 

How synchrotron X-rays are generated and how research is done with them? Here is one recent video from a canadian synchrotron explaining basic operation:

http://globalnews.ca/video/1439365/synchrotron-matters

(via @CanLightSource, @lightsources)

 

Follow ESRF in Twitter: @esrfsynchrotron

 

more...
No comment yet.
Rescooped by Mikko Hakala from Science: resources for South African teachers
Scoop.it!

▶ How Chemistry Creates Really Big Bubbles | Outrageous Acts of Science - YouTube

Everyone loves bubbles... but you've never seen them quite like this. Great video for introducing surface tension.


Via Andrew van Zyl
Mikko Hakala's insight:

What keeps the bubble from bursting? Learn about

 

* the role of surface tension

* how to lower it

* how to avoid water evaporation

 

2 minute video.

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Shatterproof screens that save smartphones

Shatterproof screens that save smartphones | Physics | Scoop.it
University of Akron polymer scientists have developed a transparent electrode that could change the face of smartphones, literally, by making their displays shatterproof.
Mikko Hakala's insight:

Current touch displays are capacitive and they need transparent conducting layers as part of the structure. ITO (indium tin oxide) glass is the most often used technology for these layers. However, it is costly and brittle, so alternatives are sought. 

 

This article presents a metal-nanowire based alternative film, which has better properties than ITO (better conductivity and flexibility). There are also other alternatives, for example based on carbon nanotubes or polymers. These kind of findings are potentially important since there seems to be big a market to replace ITO.

 

An excellent explanation (5 pages) of the technology of touch screens can be found here: http://www.computerworld.com/s/article/9231961/How_it_works_The_technology_of_touch_screens

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Team first to detect exciton in metal

Team first to detect exciton in metal | Physics | Scoop.it
University of Pittsburgh researchers have become the first to detect a fundamental particle of light-matter interaction in metals, the exciton. The team will publish its work online June 1 in Nature Physics.
Mikko Hakala's insight:

Observation of excitons in metals is difficult due to their short lifetimes. This research reports detection on metal surfaces via multiphoton photoemission.

 

Quick info on excitons: http://en.wikipedia.org/wiki/Exciton

 

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Design and synthesis of the first triply twisted Möbius annulene : Nature Chemistry : Nature Publishing Group

Design and synthesis of the first triply twisted Möbius annulene : Nature Chemistry : Nature Publishing Group | Physics | Scoop.it
Most cyclic conjugated molecules, such as benzene, exhibit two sides. Möbius annulenes, however, with an odd number of 180° twists in their π system are one-sided and violate the Hückel rule. Now, using a topological trick it is demonstrated that triply twisted systems are not particularly strained and probably easier to synthesize than singly twisted ones.
Mikko Hakala's insight:

Topology and chemistry combined: Annulene in a Möbius ring configuration with three twists. Applications could be found in optoelectronics and nanotechnology.

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

New insight into the temperature of deep Earth

New insight into the temperature of deep Earth | Physics | Scoop.it
Scientists from the Magma and Volcanoes Laboratory (CNRS) and the European Synchrotron, the ESRF, have recreated the extreme conditions 600 to 2900 km below the Earth's surface to investigate the melting of basalt in the oceanic tectonic plates. They exposed microscopic pieces of rock to these extreme ...
Mikko Hakala's insight:

135 GPa and 3800 K conditions prepared at the laboratory scale, to study the melting behaviour of geological materials in the Earth's mantle. The article gives a glimpse on some current issues and investigations.

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Astronomers create first realistic virtual universe

Astronomers create first realistic virtual universe | Physics | Scoop.it
Move over, Matrix - astronomers have done you one better. They have created the first realistic virtual universe using a computer simulation called 'Illustris.' Illustris can recreate 13 billion years of cosmic evolution in a cube 350 million light-years on a side with unprecedented resolution.
Mikko Hakala's insight:

Impressive. The simulation is said to model both the chemistries of individual galaxies and the large-scale structures (galaxy clusters, bubbles and voids of the cosmic web).

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Breakthrough in Study of High-Temperature Superconductivity | Simons Foundation

Breakthrough in Study of High-Temperature Superconductivity | Simons Foundation | Physics | Scoop.it
Experimentalists have pinpointed the microscopic structure of waves inside high-temperature superconductors, which could be the key to understanding the complex materials.
Mikko Hakala's insight:

An interesting, broad and detailed article about the current advancements in understanding the microscopic origin of superconductivity in cuprates. 

 

The article discusses recent findings by various groups. In particlar, it addresses the details of the d-wave charge density order, and how antiferromagnetism is the parent state both to superconductivity and to charge density waves.

 

Challenges remain, for example "[a recently proposed theoretical framework] is not yet refined enough to predict how the balance of charge density waves and superconductivity vary with temperature, magnetic field or type of cuprate."

 

In short, this is a clarifying expert article on a specific condensed matter topic, the origin of d-wave superconductivity and the nature of charge density waves in cuprates.

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

High-temperature superconductivity in the iron pnictides

High-temperature superconductivity in the iron pnictides | Physics | Scoop.it
Mikko Hakala's insight:

Here is a set of resources for iron pnictides.

 

* Focus article by M. R. Norman, 2008 (the main link) 

http://physics.aps.org/articles/v1/21

 

* Some recent studies

http://phys.org/news/2013-12-iron-age-high-temperature-superconductivity.html

http://www.emfl.eu/research/highlights/pnictides-go-critical.html

http://www.annualreviews.org/doi/abs/10.1146/annurev-conmatphys-031113-133921

http://phys.org/news/2013-11-infrared-gap-iron-based-superconductor.html

 

* Groups

http://arpes.stanford.edu/research_fe_pnictides.html

http://www.stanford.edu/group/fisher/research/Fe_pnictides.html

 

 

 

 

 

 

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

This Stellar Fusion Game is Shockingly Addictive

This Stellar Fusion Game is Shockingly Addictive | Physics | Scoop.it
Stars are colossal fusion reactors, burning hydrogen into helium. As the nuclei fuse lighter elements into heavier elements, massive amounts of energy are released. A new game sets you the task of nucleosynthesis, building hydrogen into iron, and it's surprisingly fun.
Mikko Hakala's insight:

Now here is a review of a game where you get to control nucleosynthesis. Nice way to learn about fusion in stars.

 

The game: http://newbrict.github.io/Fe26/

 

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Scientists capture ultrafast snapshots of light-driven superconductivity

Scientists capture ultrafast snapshots of light-driven superconductivity | Physics | Scoop.it
A new study pins down a major factor behind the appearance of superconductivity—the ability to conduct electricity with 100 percent efficiency—in a promising copper-oxide material.
Mikko Hakala's insight:

X-ray studies bring insight into developing room-temperature superconductors. This laser pump - x-ray probe experiment showed that the appearance of superconductivity is not related to lattice distortions (the distortions persist longer than the melting of charge stripes, i.e. the point where superconductivity emerges).

 

The findings are relevant for understanding generally the mechanism of superconductivity in layered copper oxide materials, and in the new field of light-induced superconductivity.

 

The experimental x-ray method used was resonant soft x-ray diffraction.

more...
No comment yet.
Scooped by Mikko Hakala
Scoop.it!

Finnish inventor rethinks design of the axe

Finnish inventor rethinks design of the axe | Physics | Scoop.it
(Phys.org) —Finnish inventor Heikki Kärnä is the man behind the Vipukirves Leveraxe, which is a precision tool for splitting firewood. He designed the tool to make the job easier and more efficient, with no need for an external source of energy. In short, he has redesigned the axe. This is a lever-based ...
Mikko Hakala's insight:

Clever physics-based improvements for manual wood splitting. Great example of creativity!

more...
No comment yet.