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In the spectrum of an emission-line region ejected from the massive star Eta Carinae, called the strontium filament (SrF), forbidden lines from many elements, in particular [Sr ii] and [Ti ii], are observed. These lines are strong in this specific region and valuable for plasma diagnostics. Forbidden lines are not easily produced in laboratory light sources and the atomic parameters for these lines can thus not be measured in a straightforward way. We use a combination of laboratory and astrophysical measurements to determine transition probabilities for the [Ti ii] lines. Lifetimes for metastable levels in Ti ii are measured using a laser probing technique on a stored ion beam at CRYRING, MSL, Stockholm. Branching fractions from some of these levels are derived from Hubble Space Telescope/STIS spectra of the SrF. The astrophysical branching fractions are combined with the experimental lifetimes to determine absolute transition probabilities. We report lifetimes for the Ti ii levels b4P3/2, b2P1/2, c2D3/2 and c2D5/2, in the range 0.29–17 s, and transition probabilities for eight parity-forbidden lines from the levels c2D3/2 and c2D5/2, along with uncertainty estimates. [ABSTRACT FROM AUTHOR]

• Fabrication process of various-shape well-defined microstructures is developed. • Vacuum processing decreased wettability transformation time from days to 4 h. • Faster development of non-polar hydrocarbon layer in vacuum revealed by XPS. • Ultrahydrophobic surfaces with CA > 170° and SA < 5° demonstrated. A lot of research efforts have been invested in the fabrication of superhydrophobic surfaces in recent years due to many protentional applications in science and industry including anti-icing, self-cleaning and anti-corrosive surfaces. Laser as a non-polluting, precise and flexible tool can be applied to replicate surface microstructures of extremely water repellent lotus leave surface. In this study, a common nanosecond laser source is used to fabricate a super/ultrahydrophobic surfaces with different microstructure designs, contact angles above 170° and sliding angles below 5°. The freshly processed surface is hydrophilic and becomes hydrophobic and superhydrophobic in a certain time period, which could be dramatically reduced by storing samples in high vacuum. The transformation in wetting properties are analysed with respect to surface geometry and surface chemistry. [ABSTRACT FROM AUTHOR]

The metallic surfaces with low affinity or high repellence towards water molecules are extremely desirable. The present investigation reports the development of non-fluorinated super or ultrahydrophobic aerospace aluminum alloy (Al7075) surface by laser patterning and high vacuum process for 4 h. Lamellar and lotus leaf papillae like structures covered with nanoscale protrusions are found to be formed depends on the laser fluence and spatial shifts of laser scans. The fresh laser processed hydrophilic surface was vacuum processed to create layer of hydrocarbon to reduce the surface free energy for the wetting property transformation. The analysis of the results shows the synergistic effect of hierarchical structures and dominant presence of non-polar elements is critical for superhydrophobic property. The surface geometry is primarily responsible for the wetting property transformation by entrapping μ-volume of air to generate a composite interface of solid-gas-liquid. Micro and nanoscale (dual scale) surface structures are essential for the durable and consistent superhydrophobic property with high degree of water repellence for bigger volume of water droplets. Further, sole presence of nanoscale structures on inherent hydrophilic aluminum alloy surface with predominant presence of non-polar elements can yield only near superhydrophobic surface due to random spacing of nanoscale protrusions. Unlabelled Image • Lamellar and lotus leaf papillae structures are covered with nanoscale protrusions recorded high contact angle of 180°. • The surface with nanostructure recorded a near superhydrophobic (SCA:130 to 145°). • The random spacing of the nanostructures causes adhesion to water droplets. • The hierarchical structure provides a stable and durable superhydrophobic surface. [ABSTRACT FROM AUTHOR]

• Fabrication of superhydrophobic µ-structures on CFRP PEEK composite is studied. • Melt- and crack-free ns DLIP processing of hierarchical µ-structures is developed. • µ-structure wettability is mainly dependent on periodicity, depth and quality. • Superhydrophobic surfaces with the CA > 170° and the SA < 2° are demonstrated. The fabrication of functional microstructures on surfaces by laser enables unique material properties and is presently a leading research topic. This work addresses the production of functional hierarchical microstructures on carbon fibre reinforced polymer composites in order to control the wettability properties of the material. Two-beam Direct Laser Interference Patterning using either ultraviolet (263 nm) or infrared (1053 nm) nanosecond laser source is employed to produce melt-free and well-defined hierarchical microstructures on carbon fibre reinforced plastics. The resulting water contact angles after thin film deposition of 1H,1H,2H,2H-Perflorodecyl-triethoxysilane were analysed with respect to structure depth and quality. The maximum static contact angle of 171° is demonstrated for dual hierarchical microstructures composed of 11 µm deep large-scale pillars, covered by 1.7 µm pillars, both fabricated in a single step. [ABSTRACT FROM AUTHOR]

Superhydrophobic surfaces attract a lot of attention due to many potential applications including anti-icing, anti-corrosion, self-cleaning or drag-reduction surfaces. Despite a list of attractive applications of superhydrophobic surfaces and demonstrated capability of lasers to produce them, the speed of laser micro and nanostructuring is still low with respect to many industry standards. Up-to-now, most promising multi-beam solutions can improve processing speed a hundred to a thousand times. However, productive and efficient utilization of a new generation of kW-class ultrashort pulsed lasers for precise nanostructuring requires a much higher number of beams. In this work, we introduce a unique combination of high-energy pulsed ultrashort laser system delivering up to 20 mJ at 1030 nm in 1.7 ps and novel Diffractive Laser-Induced Texturing element (DLITe) capable of producing 201 × 201 sub-beams of 5 µm in diameter on a square area of 1 mm 2 . Simultaneous nanostructuring with 40,401 sub-beams resulted in a matrix of microcraters covered by nanogratings and ripples with periodicity below 470 nm and 720 nm, respectively. The processed area demonstrated hydrophobic to superhydrophobic properties with a maximum contact angle of 153°.

We present the setup of a compact, q-switched, cryogenically cooled Yb:YAG laser, which is capable of producing over 1 J output energy in a 10 ns pulse at 10 Hz. The system's design is based on the recently published unstable cavity layout with gain shaping of the spatial intra-cavity intensity distribution. Using a hexagonal homogenized pump beam, the laser generated an according hexagonal output beam profile. The suitability of such laser properties for the intended use in a laser shock peening process is demonstrated. In the experiment an aluminum plate was treated and the generated residual stresses in the sample subsequently measured. Other applications of this laser system like laser pumping or surface cleaning are conceivable.

Reflectivity and surface topography of tempered glass were modified without any thermal damage to the surroundings by utilizing 1.7 ps ultrashort pulsed laser on its fundamental wavelength of 1030 nm. To speed up the fabrication, a dynamic beam shaping unit combined with a galvanometer scanning head was applied to divide the initial laser beam into a matrix of beamlets with adjustable beamlets number and separation distance. By tuning the laser and processing parameters, reflected intensity can be reduced up to 75% while maintaining 90% of transparency thus showing great potential for display functionalization of mobile phones or laptops.

A series of tacrine - benzothiazole hybrids incorporate inhibitors of acetylcholinesterase (AChE), amyloid β (Aβ) aggregation and mitochondrial enzyme ABAD, whose interaction with Aβ leads to mitochondrial dysfunction, into a single molecule. In vitro, several of 25 final compounds exerted excellent anti-AChE properties and interesting capabilities to block Aβ aggregation. The best derivative of the series could be considered 10w that was found to be highly potent and selective towards AChE with the IC 50 value in nanomolar range. Moreover, the same drug candidate exerted absolutely the best results of the series against ABAD, decreasing its activity by 23% at 100 µM concentration. Regarding the cytotoxicity profile of highlighted compound, it roughly matched that of its parent compound - 6-chlorotacrine. Finally, 10w was forwarded for in vivo scopolamine-induced amnesia experiment consisting of Morris Water Maze test, where it demonstrated mild procognitive effect. Taking into account all in vitro and in vivo data, highlighted derivative 10w could be considered as the lead structure worthy of further investigation., (Copyright © 2020 Elsevier Inc. All rights reserved.)

In this paper, we introduce a method to efficiently use a high-energy pulsed 1.7 ps HiLASE Perla laser system for two beam interference patterning. The newly developed method of large-beam interference patterning permits the production of micro and sub-micron sized features on a treated surface with increased processing throughputs by enlarging the interference area. The limits for beam enlarging are explained and calculated for the used laser source. The formation of a variety of surface micro and nanostructures and their combinations are reported on stainless steel, invar, and tungsten with the maximum fabrication speed of 206 cm 2 /min. The wettability of selected hierarchical structures combining interference patterns with 2.6 µm periodicity and the nanoscale surface structures on top were analyzed showing superhydrophobic behavior with contact angles of 164°, 156°, and 150° in the case of stainless steel, invar, and tungsten, respectively.

To fulfil the requirements for high-resolution organic light-emitting diode (OLED) displays, precise and high-quality micrometer-scale patterns have to be fabricated inside metal shadow masks. Invar has been selected for this application due to its unique properties, especially a low coefficient of thermal expansion. In this study, a novel cost-efficient method of multi-beam micromachining of invar will be introduced. The combination of a Meopta beam splitting, focusing and monitoring module with a galvanometer scanner and HiLASE high-energy pulse laser system emitting ultrashort pulses at 515 nm allows drilling and cutting of invar foil with 784 beams at once with high precision and almost no thermal effects and heat-affected zone, thus significantly improving the throughput and efficiency.

A novel method to shape the intensity distribution within an unstable laser cavity is demonstrated. This method is characterized by inscribing a tailored gain profile generated by a spatially tophat-shaped longitudinal pump beam into the gain medium. The mode shaping mechanism is still effective with zero output coupling. Therefore, this method enables to operate unstable laser cavities in cavity dump mode or as a regenerative amplifier. The theoretical background is described by means of geometrical optics, and operation of a prototype setup using cryogenically cooled Yb:YAG is demonstrated. The system produces 13ns pulses with 285 mJ at a repetition rate of 10 Hz, with an extraction efficiency of 35 %. Successful cavity dump operation is demonstrated with 110 mJ output energy.

An experimental investigation of the radiative lifetime of the metastable 4s24p4(3P)4d4D7/2 level in Kr II shows an unusual situation regarding the importance of an M2 depopulation channel. While the first order M1 and E2 channels are expected to contribute in a dominant way to the decay, the experimental result, obtained using a laser probing technique on a stored ion beam, tau = 0.57+/-0.03 s, is far too short to be due to these channels according to our relativistic multiconfiguration Dirac-Fock calculation. Only if second order contributions to the decay branches (including essentially the M2 contribution) are taken into account in the calculations could the unexpected short lifetime be explained.

The lifetime of two metastable levels in Fe+ has been measured by laser probing of a stored ion beam. In the dense spectrum of Fe+, the metastable levels a (6)S(5/2) and b (4)D(7/2) were selected and their lifetimes were determined to be 230 +/- 30 and 530 +/- 30 ms, respectively. The lifetimes are compared with previous theoretical results. Metastable lifetime measurements of Fe+ are of great importance for interpretation of spectra from astronomical objects. The present experiment opens for the possibilities to investigate lifetimes of metastable states in complex atomic ions, which have, so far, been unexplored.