PSG boss breaks his silence on Adrien Rabiots future

first_imgNew Paris Saint-Germain manager Thomas Tuchel would like to keep a hold on Adrien Rabiot, but admits that it is something that is completely out of his controlThe French midfielder has under 12 months left on his contract at the Parc Des Prices and has been heavily linked with Barcelona this summer.But the interest from the La Liga champions appears to have cooled with Ernesto Valverde’s side in need of a new midfield option now after the departures of club legend Andres Iniesta and Paulinho.While Juventus have emerged as another possible destination for Rabiot and are reportedly prepared to wait until next summer to sign the highly-rated 23-year-old.Franck Ribery, FiorentinaFiorentina owner: “Ribery played better than Ronaldo!” Andrew Smyth – September 14, 2019 Fiorentina owner Rocco Commisso was left gushing over Franck Ribery’s performance against Juventus, which he rates above that of even Cristiano Ronaldo’s.“Of course, I would love to see him stay. Everyone has seen his potential and there’s room for improvement,” said Tuchel, according to Calcio Mercato.“When it comes to his contractual situation, it’s he who has the last word. It’s all up to him, he could stay and adapt to our style or leave the club to start a new experience,” Tuchel concluded.Juventus have recently signed a new midfielder in Emre Can on a free transfer from Liverpool and will likely be prepared to wait for Rabiot as a free agent after spending €112m on the signing of Cristiano Ronaldo from Real Madrid.last_img read more

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Yellow Bird Dancers To Visit Kenai

first_imgThe Yellow Bird dancers perform a mix of traditional dances as well contemporized versions set to modern music to get more young people interested and engaged. Hoop dances are always the finale. The show will feature a special appearance by Nick Hanson, the “Eskimo Ninja.” Nick, who is Inupiaq, was born and raised in Unalakleet and has become a fan favorite on “American Ninja Warrior.” Tickets are $15 and are available at the Kenaitze Indian Tribe’s administration building at 150 N. Willow Street in Kenai, and will be sold at the door. The event is a fundraiser for the Tribe’s Yaghanen Youth Program. Facebook0TwitterEmailPrintFriendly分享Yellow Bird Productions, an internationally known indigenous dance group, will perform at Kenai Central High School on Saturday, January 19, at 7 p.m.center_img The evening also will include a performance by the Kenai Central High School Drumline, under the direction of Deborah Sounart. Yellow Bird Productions is under the direction of Ken Duncan, a member of the San Carlos Apache Tribe. Duncan says he emphasizes to audiences that Yellow Bird performances are based on family strength.last_img read more

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Bumblebee director on replacing Michael Bay I couldnt go bigger

first_imgIt must be tough to direct your first live-action film with Steven Spielberg and Michael Bay looking over your shoulder. But for Travis Knight, director of Transformers spin-off Bumblebee, those two singular filmmakers weren’t just the movie’s producers, they provided the touchstones that inspired the film.”ET was my spirit animal in this movie”, explained Knight as I sat down with him in London to discuss Bumblebee. “I saw it when I was around 8 years old with my mom in a darkened theater and I was a big, blubbery mess at the end of it … On some levels Steven’s films from that era are responsible for me becoming a filmmaker.”And it shows: Not only is Bumblebee set in the 1980s, but the spirit of ’80s movies like ET and Short Circuit shine through in the adorable adventures of a girl and her robot buddy. CNET’s Holiday Gift Guide: The place to find the best tech gifts for 2018.Movie Magic: The secrets behind the scenes of your favorite films and filmmakers.  Now playing: Watch this: 1:34 Share your voice 2019 movies to geek out over TV and Movies Knight’s previous filmmaking experience was as an animator, directing the stunning stop-motion film Kubo and the Two Strings.”Stop motion is probably the subset of animation that’s closest to live-action,” he says, “in the sense you’re physically shooting these things with real lights and real cameras, and there’s props and sets and costumes and hair.”But there were still plenty of new things to learn on this, his first live-action film.”A lot of times I was flying by the seat of my pants,” he says, laughing.Knight brought what he called “an animator’s discipline and planning” to the film, mapping out each sequence in detail.”I do believe in the adage that the trimmer the vessel, the more it can carry,” he says. “Animation is very organized and disciplined. You can’t shoot coverage, you can’t play around. But in live-action, you can play around, and sometimes you’ll create little magical moments.” Enlarge ImageJohn Cena provides several comic highlights in Bumblebee. Jaimie Trueblood He particularly enjoyed John Cena’s ability to improvise in the role of a burly secret agent pursuing Bumblebee.”John’s like a one-man ad-lib factory. We would do the scenes, and then we get to the end of the scene, I’m like, ‘All right, John, now let’s play a little bit,’ and he would always do something really unexpected. He’s just a very, very clever, funny man.”Eye candyA major criticism of Bay’s past Transformers movies is the fast-paced computer-generated action, an assault on the senses that’s often hard to follow. While it has plenty of action, Bumblebee tones down the CG carnage. But Knight insists this shouldn’t be seen as a criticism of Bay’s style.”It wasn’t in any way addressing any feedback from the fans,” he says. “It was just a story I wanted to tell. That last one [Transformers: The Last Knight] is one of the biggest movies I’ve ever seen — and I couldn’t go bigger than that. So let’s go the other way, let’s focus in on a small corner of this canvas and really get to know one of these characters. Let’s balance the emotions with the explosions … The core relationship mattered to me more than anything else. And if that didn’t work, none of the other stuff matters. It’s just bombast. It’s just eye candy.”Mixing the spectacular, visual effects-driven action with a character-led story was “a high-wire act”, but Knight credits writer Christina Hodson for striking the right balance.”She’s gained something of a reputation in Hollywood as this kinda badass chick writer with these cool, action movies,” he says, “When you talk to her, the films that she always references are cool action movies like T2 … But when I sat down and talked to her about the film and my vision of it, I realized very quickly she has a big soft gooey heart just like I do.”Knight’s next big project is 2019’s Missing Link, a new stop-motion adventure from his animation studio Laika. As for where the Transformers movies go next, Knight is sanguine.”It’s hard to say. I think at this point, candidly, they’re probably just waiting to see how people react to [Bumblebee]. If people vote with their wallets for these kinds of Transformer movies, then they’ll get these kinds of Transformer movies.”Bumblebee opens in Australia on Dec. 20, in the US on Dec. 21 and in the UK on Dec. 24. Spielberg was a producer on Bumblebee, as was Michael Bay — the man who resurrected Transformers by directing all five previous movies in the series.”From a director’s perspective he was a dream producer,” Knight says of Bay. “We sat down early on and it was great for me, director to director, to pick his brain, to get a sense of his philosophy on the Transformers. He was really respectful and recognized this was someone else’s movie, my take on these characters, and the best thing that he could do was to support me and protect me. He let me do my thing, and I’m really appreciative of it.”Bay gave Knight one memorable piece of advice for working on a mega-budget franchise movie surrounded by people from the studio, the toy company and elsewhere all pulling a director in different directions.”He said the one thing you have to do is protect the movie,” Knight remembers. “That was advice Jerry Bruckheimer gave him, and he passed it on to me — remember the movie you intended to make and protect it.”  I do believe in the adage that the trimmer the vessel, the more it can carry. Travis Knight, Bumblebee director Post a comment 0 Tags 77 Photos Filmmakers Bumblebee transforms from action-packed to adorablelast_img read more

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Dengue not out of control yet Quader

first_imgRoad transport and bridges minister Obaidul Quader. File PhotoRuling Awami League general secretary Obaidul Quader on Thursday said the prevailing dengue situation is alarming and difficult to deal with, but not out of control yet, reports UNB.He made the remarks while delivering his speech at a photo show organised by Bangladesh Awami Jubo League, marking the Month of Mourning, at Bangladesh Shilapakala Academy in the capital.“According to media reports, some 17,000 people have been infected with dengue virus in the country. And 13,000 of them have already got back home after receiving medical treatment. You can say the situation is epidemic or whatever, but we’re working to face the situation recognising the reality,” he said.The minister went on saying, “We’ve taken this as a challenge. We’ll confront the situation under the leadership of Prime Minister Sheikh Hasina.”He said they all are worried about the situation. “The leader (PM) is concerned. She’s receiving treatment in London; yet she’s constantly consulting us and giving us directives.”When the Health Minister was abroad, his ministry’s activities did not stop, Quader said adding: “Now instructions can be given on mobile phones. He (Health Minister) may go abroad for an emergency work; he didn’t go without permission. One minister is not the full of a ministry. He has already returned home.” Quader said there is nothing unique in dengue cases in Bangladesh as it has spread in many other countries of the world.So far, he said, 800 people have died of dengue in the Philippines, and one lakh have been infected there. They have declared the situation a national disaster, he added.Quader said dengue has also spread in Vietnam. The number of dengue infected people in India is low, but it is high in Indonesia. Many people have been affected in Thailand and Singapore as well, said the minister.last_img read more

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Trump Walks Back Threat To Close US Border Giving Mexico A 1Year

first_img Share Evan Vucci/APPresident Trump said Thursday that he was giving Mexico one year to stem the flow of migrants and drugs coming across the Southern border, or else the U.S. would impose auto tariffs or close the border.President Trump is backing down from his threat to shut down the U.S. Southern border as soon as this week.Trump had issued the warning in a bid to curtail surging border crossings by asylum seekers from Central America.Instead, Trump is now giving Mexico “a one-year warning” to address his concerns about its handling of immigrants traveling through the country on the way to the United States. He also demanded that Mexico tamp down on the flow of drugs.If the Mexican government doesn’t respond in a manner acceptable to Trump within 12 months, he says, he will take action.“Mexico understands that we’re going to close the border or I’m going to tariff the cars — one or the other,” Trump said.He said he would likely start off with the auto tariffs, saying that would be a “very powerful incentive.”Trump’s warning about shutting down the border had been met with intense resistance from Republicans and some business groups, who warned there would be severe economic consequences.While Trump has walked back his plan to close the border, Democrats in the House of Representatives are moving against another immigration policy put forward by Trump.Speaker of the House Nancy Pelosi, D-Calif., has announced the House will sue to block Trump’s decision to declare a national emergency in order to construct a wall on the Southern border.“The President’s sham emergency declaration and unlawful transfers of funds have undermined our democracy, contravening the vote of the bipartisan Congress, the will of the American people and the letter of the Constitution,” Pelosi said in a written statement.The Trump administration has argued that the situation at the border is a crisis and that the president is acting within his legal authority.Copyright 2019 NPR. To see more, visit https://www.npr.org.last_img read more

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The Case for Habitable Exoplanet Moons

first_img The direct detection of terrestrial planets around stars like our Sun may have to wait until the launch of dedicated satellites such as COROT and Kepler (scheduled for 2006 and 2008, respectively). In the meantime, some researchers have begun to wonder whether these extrasolar gas giants could harbor habitable moons.Our own solar system has four gas giants, and each has been blessed with an abundance of satellites. All these moons are far smaller than the Earth, but six could qualify as planets in their own right if they orbited the Sun: Jupiter’s four Galilean satellites Europa, Callisto, Ganymede, and Io; Saturn’s Titan; and Neptune’s Triton. Europa is known to have large amounts of water ice, and Titan has a thick atmosphere. If our solar system is not atypical, many of the known exoplanets probably have rich moon systems as well.Caleb Scharf, Columbia University’s Director of Astrobiology, has been exploring the conditions necessary for such moons to be habitable. His recent work investigates the conditions necessary for a moon to contain enough water to sustain biological life, at temperatures capable of supporting biological activity. Under zero-pressure conditions, water ice will sublimate (transform from solid to vapor directly) at temperatures higher than about 170 K (-103 °C). This means that water-rich protoplanets must form relatively far from the star — well outside the traditional “habitable zone” where stellar radiation raises temperatures high enough to support liquid water. Gas giants are also likely to form in these icy reaches — so the known exoplanets are highly likely to have acquired one or more icy moons early on. Icy moons may be carried into warmer regions later, as the host planet migrates inward.What happens to the water then? The answer depends mainly on the size of the moon. A moon or planet with about 10% the Earth’s mass has enough gravity to retain water vapor and other gases in a temperate atmosphere. (As a counterexample, Venus has enough gravity but is much too hot to retain water — the speed of water molecules in the atmosphere exceeds the escape velocity of the planet.) Mars-sized or larger moons may therefore be able to sustain both an atmosphere and liquid water, if their host planet is not too far from the star. More Heat Kneaded!Scharf is able to show that such moons may be habitable at greater distances than a similar planet would be, thanks to the process of tidal heating. Since gravity weakens with distance, the pull from the host planet will be slightly different on the near and far sides of a moon. If the moon’s orbit is circular this gravity differential will be constant, and the moon can adjust to it by changing its shape slightly. When a moon travels in an eccentric orbit around its planet, however, it approaches and recedes at regular intervals. The gravity differential therefore changes slightly as it orbits, resulting in a rhythmic compression of the moon’s core. In other words, the host planet will slowly knead the moon like a lump of dough. The activity can generates a lot of heat, even if the moon’s core is not molten. “You’re basically draining the spin energy of the parent planet.” Scharf explains. In the case of Jupiter, that spin energy is enormous—more than enough to sustain moderate levels of tidal heating indefinitely. To sustain the eccentricity of its moons’ orbits, the ideal exoplanet will have multiple moons in proximity (such as Jupiter’s Galilean satellites). To illustrate the potency of this process, Scharf offers the following example. “If you took Mars and put it where Europa is now, Mars would get heated by several tens of degrees [from tidal heating] at its surface. This would also probably start up its volcanic activity again.” Tidal heating can give an extra boost of energy to moons which receive too little light from the system’s star to thaw. Scharf finds that an Earth-sized moon could reach habitable temperatures about twice as far from the Sun as the Earth itself, under favorable assumptions.Most moons in the Solar system, however, are not large enough to hold an atmosphere; Ganymede is the largest, at about 0.025 (1/40) Earth masses. Scharf therefore postulates that habitable moons such as Europa are much more likely. The surface temperature of such moons must be cold enough to preserve ice even in the absence of an atmosphere, but the process of tidal heating could potentially warm the planet enough to create a warm, liquid ocean under the ice layer. Evidence of liquid water has not only been found on Europa, but also recently on Saturn’s moon Enceladus by the Cassini mission(http://www.solarviews.com/eng/enceladuswater.htm). Again, tidal heating is thought to be the culprit.In his most recent paper Scharf analyzes the properties of 74 exoplanets, those far enough from their star for satellite orbits to be stable over several billion years. He finds that between 28 and 51% of the planets in this sample are capable of harboring Europa-like moons with icy mantles and liquid water, depending on the size of the satellites and the eccentricity of their orbits. When one considers the total population of known exoplanets, the fraction falls to 15 to 27%, which is still quite favorable. Even if the planetary systems discovered so far lack Earth-like worlds, Scharf’s work makes a strong case that the moon systems of gas giants could also sustain life.Reference: Caleb A. Scharf, “The potential for tidally heated icy and temperate moons around exoplanets” 2006, to appear in Astrophysical Journal. http://xxx.lanl.gov/astro-ph/0604413By Ben Mathiesen, Copyright 2006 PhysOrg.comBen Mathiesen is an astrophysicist at the Service d’Astrophysique in Saclay, France, and owner of the agency Physical Science Editing, which helps researchers around the world meet native English writing standards in their academic publications. India prepares to land rover on moon in global space race Citation: The Case for Habitable Exoplanet Moons (2006, April 27) retrieved 18 August 2019 from https://phys.org/news/2006-04-case-habitable-exoplanet-moons.html Artist’s impression of an exoplanet. Credit: European Southern Observatory.center_img Explore further As scientists refine their methods, exoplanets are becoming easier and easier to detect. The current count is 163 planets orbiting 97 main-sequence stars, of which only one is even remotely Earth-like. All the others are massive bodies, ranging from “tiny” Uranus-like worlds (at about 15 Earth masses) to super-Jupiters (at thousands of Earth masses). This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

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Threedimensional femtosecond laser nanolithography of crystals

first_img Explore further Wet etching nanopore lattices engineered by 3DLW in YAG. a) Nanopore lattice etched for 120 hours with average pore dimensions (257 ± 7 nm and 454 ± 13 nm) along x and y directions and 1 mm length along z. b) Vertically overlapping nanopores after 2 h wet etching (average dimensions of 131 ± 5 nm and 1,300 ± 35 nm along x and y, and 1 mm lengths). c) Top optical microscope view of nanopores along the z direction etched for 1 hour (129 ± 6.8 µm length). Credit: Nature Photonics, doi: https://doi.org/10.1038/s41566-018-0327-9 Etching nanopores in YAG along mm to cm scale lengths. (A) Optical microscope side view of etched pores. (B) Optical microscope top view of etched nanopores. (C) SEM side view of etched nanopores. Credit: Nature Photonics, doi: https://doi.org/10.1038/s41566-018-0327-9. Subwavelength diffraction gratings and MOW (micro optical waveguides) in YAG (yttrium aluminum garnet) crystals. a) Image of a centimeter-long, 700 nm pitch grating under visible light illumination. b) Experimental and calculated absolute diffraction efficiencies of a subwavelength grating (700 nm pitch) with 1,070 nm wavelength. Efficiency is calculated as the diffracted power divided by the power incident to the embedded grating. Error bars correspond to the experimental standard deviation of ~0.07%. Inset: scanning electron microscopy (SEM) close-up image of the fabricated grating. c) Optical waveguide with hexagonal structure, 500 nm horizontal pore-to-pore spacing, mean pore size of 166 × 386 nm^2 and 4 mm length. d) Simulated intensity mode profile at 1,550 nm with full-width at half maximums (FWHMs) of 862 nm (vertical) and 972 nm (horizontal). e) Diffraction- limited near-field image of the waveguide output mode measured at 1,550 nm, with a FWHM of ~1.5 µm. Credit: Nature Photonics, doi: https://doi.org/10.1038/s41566-018-0327-9 Within 170 hours, the scientists achieved nanopores with cross-sections of 368 x 726 nm2 and lengths of 3.1 mm; to show that nanopores with millimeter-scale length could be engineered in a single etching step. Nanophotonic devices typically require such lattice dimensions from the micrometric to the centimeter scale, without brittle fracture of the crystal due to excessive stress. In this way, the scientists implemented a scheme to homogenously etch nanostructures and microstructured optical waveguides (MOWs), on the desired scale across the whole sample.To test if the observed selectivity of nanopore etching with YAG was transferrable to other crystal types, the scientists conducted similar experimental nanostructuring with sapphire. They found a parallel nanopore etch rate of ~1 x 105 in sapphire, similar to YAG and higher than the rate previously observed with microchannels etched in sapphire. Ródenas and co-workers formed millimeter-long nanopores in sapphire with cross-sections as small as ~120 nm and tested the feasibility of the method by engineering nanopore lattices etched for 170 hours without fracturing the crystal. The results showed an etching selectivity at a value larger than 1 x 105 at the molecuar level between the modified and pristine crystalline states, hitherto not observed in a photo-irradiated material. The observed value was approximately two orders of magnitude higher than that of alumina etch masks on silicon. Ródenas et al. determined the etching rate of unmodified YAG at ~1 nm/hour. The proposed method allowed the design and fabrication of nanophotonic elements inside a crystal that could provide the desired optical responses, at the subwavelength structure. The scientists were able to control the features of pore direction, size, shape, filling fraction and length of nanopore lattices in YAG crystals by combining 3DLW and wet etching.The YAG lattice was etched for 120 hours to obtain average pore dimensions in the x and y directions. The pore shape and size were controlled by tailoring the laser power and polarization. The diameter of etched nanopores depended on the laser power and could be studied for both linear and circular laser beam polarizations. As limitations of the technique, they found that 3-D photonic structures were characteristically isolated in space, needed supporting walls, and suffered shrinkage and a low optical damage threshold. Optical properties of materials are based on their chemistry and the inherent subwavelength architecture, although the latter remains to be characterized in depth. Photonic crystals and metamaterials have proven this by providing access through surface alterations to a new level of light manipulation beyond the known natural optical properties of materials. Yet, in the past three decades of research, technical methods have been unable to reliably nanostructure hard optical crystals beyond the material surface for in-depth optical characterization and related applications. The capability to control lattice formation down to the nanometer scale will be useful in practical photonic applications. For instance, photonic bandgap lattices can be designed with stopbands in the visible to mid-infrared range in solid-state laser crystals for photonic information technology. To further expand the potential of the 3-D nanolithography technique, Ródenas et al. engineered MOW (microstructured optical waveguides) with different lattice spacings and cavity sizes. They obtained dimensions in the range of a centimeter in length, with 700 nm pitch grating observed under visible light illumination. Ródenas et al. conducted theoretical and simulation methods of the subwavelength gratings prior to their material fabrication. For the numerical simulations, they used the finite element method (FEM) in COMSOL Multiphysics 4.2 software. The scientists used the same FEM software and method to model YAG MOWs prior to fabrication.This ability to create controlled 3-D nanostructures of crystals opens up new routes to design compact, monolithic solid-state lasers. The resulting crystals can incorporate traditional cavity elements (gratings, fibres, microfluidic cooling channels) or novel microresonators inside the crystal. The prospect of engineering large, nanostructured laser crystals will provide a new basis for precision technology in metrological applications and allow for potentially new applications with ultra-strong deformable laser nanofibers in microelectronics and for drug delivery in medicine. © 2019 Science X Network (1). Evolution of pore size and cross-sectional aspect ratio as a function of laser power for linear and circular polarizations in YAG. (A) Power dependence of pore widths (in red) and heights (in blue) for linear (LP) and circular (CP) polarizations, measured from pores etched for 1h. (B) Dependence of cross-sectional pore aspect ratio (height divided by width) for linear and circular polarizations. (2) Etching crisscrossed nanopores. (A) The large index contrast between etched and un-etched pores is depicted in a raw bright-field transmission image. (B) 3D sketch of 90º crossing pores at different vertical offset positions. (C, D) SEM pictures of crossing pores at 90º and different crossing heights. Ag sputtered nanoparticles are also visible on the main surface. (E) Close-up view of the inner smooth surface of a pore. Credit: Nature Photonics, doi: https://doi.org/10.1038/s41566-018-0327-9 Journal information: Nature Photonics In the experiments, the scientists used a standard 3DLW with an ytterbium mode-locked ultrafast fiber laser (1030 nm wavelength and 350 fs pulse duration). A 1.4 numerical aperture (NA) oil-immersion objective was used to tightly focus the laser pulses inside the crystals. Ródenas et al. used computer-controlled XYZ linear stages for 3-D nanopositioning of the samples. After laser irradiation, they laterally polished the crystals to expose the irradiated structures followed by wet chemical etching. For this, the YAG crystals were etched in hot phosphoric acid in deionized water. A key technical limitation of the etching process was the difficulty in refreshing the exhausted acid inside the nanopores fabricated using the method detailed. , Nature Materials (1) Scheme to achieve infinitely long and homogeneously etched nanopore lattices by means of 3D-connecting etching pores. (A) 3D sketch of the vertical etching channels architecture for etching microstructured optical waveguides (MOWs). (B) SEM of a polished cut through a MOW partially revealing 3D etching pores. (C) Microscope top view of an etched array of MOWs with vertical etching channels every 80 µm. (2) Etching mm long pores in sapphire. a) Dark-field image of three arrays of 1-mm-long pores after 170 h of total etching time. Pores on each array were written at ~10 mW and at depths ranging from 4 to 30 µm. b) Example of pores written at medium power (9.4 mW) and 29 µm depth, after 30 min etching. c) Example of two pores written at 24 µm depth and at the photo-modification power threshold (~4 mW) for which no secondary pores are observed. Credit: Nature Photonics, doi: https://doi.org/10.1038/s41566-018-0327-9. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Three-dimensional femtosecond laser nanolithography of crystals (2019, January 15) retrieved 18 August 2019 from https://phys.org/news/2019-01-three-dimensional-femtosecond-laser-nanolithography-crystals.html More information: Airán Ródenas et al. Three-dimensional femtosecond laser nanolithography of crystals, Nature Photonics (2018). DOI: 10.1038/s41566-018-0327-9Markus Deubel et al. Direct laser writing of three-dimensional photonic-crystal templates for telecommunications, Nature Materials (2004). DOI: 10.1038/nmat1155 Amit Banerjee et al. Ultralarge elastic deformation of nanoscale diamond, Science (2018). DOI: 10.1126/science.aar4165 , Science For example, laser lithography developed by the semiconductor industry is a surface-processing technique used for efficient etching of a range of materials, including silicon, silica glass and polymers. The process can produce high-quality two-dimensional (2-D) nanophotonic devices that can be extended to 3-D, which was demonstrated two decades ago with infrared femtosecond laser direct writing. However, the photopolymerized structures are impractical as they cannot be interfaced with other photonic elements. While 3-D nanostructured optical fibres have delivered functionalities well beyond those possible with ordinary unstructured glass to revolutionize nonlinear optics and optical communications, reliable manufacture of materials in crystalline media has remained elusive.Alternative methods include direct machining 3-D nanostructures with laser-induced dielectric breakdown and micro-explosions triggered inside transparent crystals to form voids and induce sub-micrometer structures within them. But such methods occurred at the risk of extended lattice damage and crack propagation. Therefore, despite efforts, a standard method for large-scale, 3-D volume crystal nanostructuring remains to be reported.In a recent study published in Nature Photonics, Airán Ródenas and co-workers at the Institute of Photonics and Nanotechnology and the Department of Physics departed from existing methods of engineering the crystal nanoarchitecture. Instead, they proposed a method whereby the inner chemical reactivity of a crystal, given by its wet etch rate, could be locally modified at the nanoscale to form dense nanopore lattices using multiphoton 3-D laser writing (3DLW). The interdisciplinary scientists showed that centimeter-long empty pore lattices with arbitrary features at the 100 nm scale could be created inside key crystals such as yttrium aluminum garnet (YAG) and sapphire, typically used for practical applications. Ródenas et al. performed direct laser writing before etching, creating the desired pore architecture inside the solid-state laser crystal for photonic applications. New insight into nanopatterning diamond The scientists engineered the photonic structures using circular polarization to reproducibly create air pores in the nanoscale region below 200 nm. The nanophotonic structures (air pore photonic lattices) created in the crystal maintained spatial resolution equivalent to that obtained with state-of-the-art multiphoton polymerization lithography. For practical applications, nanophotonic devices require robust and efficient optical interconnections to form large, complex circuit designs with other optical elements. To achieve this, Ródenas et al. controlled the differential etch rate to maintain large pore lengths between the photomodified volumes and the surrounding crystal. They used scanning electron microscopy (SEM) to observe and prove the 3-D etching process. last_img read more

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Mamata leaves today for 3day Delhi visit to attend meet on 150th

first_imgKolkata: Chief Minister Mamata Banerjee will set out for her three-day-long visit to Delhi on Tuesday.Banerjee will be attending a meeting, where there will be discussion over the programme schedule to observe the 150th birth anniversary of Mahatma Gandhi. Prime Minister Narendra Modi will also be present in the meeting of the national level committee, comprising all chief ministers, Gandhians and eminent people from different walks of life. The Bengal government will also celebrate the 150th birth anniversary of the father of the nation and it will begin from October 2 at Gandhi Bhavan in Beliaghata. The state government has set up a 46-member committee with Chief Minister Mamata Banerjee as its chairperson and the committee has already held its first meeting. Also Read – Heavy rain hits traffic, flightsThe state government has taken all necessary measures for restoration of the Gandhi Bhavan. Besides organising essay competitions and publishing booklets, the state government has also decided to place a permanent chair in the name of Gandhiji at Calcutta University.The Chief Minister will be staying in Delhi till May 3. Though the main objective of her visit is to attend the May 2 meeting over the programme schedule to observe the 150th birth anniversary of Mahatma Gandhi, her visit has come up to be a crucial one, at a time when anti-BJP leaders from different states are in constant touch with her to form the Federal Front, to ensure a one-to-one fight in the general elections in 2019. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedIt may be recalled that during her last visit to Delhi in March, she had met former Congress president Sonia Gandhi. She had held meeting with eminent leaders, including National Congress Party chief Sharad Pawar. In a recent development in connection with the formation of an anti-BJP front, Telangana Chief Minister K Chandrasekhar Rao and DMK working president MK Stalin had a telephonic conversation with Banerjee on Sunday. It may be recalled that Rao had held a meeting with Banerjee in Nabanna on March 19.last_img read more

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