Green Wavelength Femtosecond Laser Ablated Copper Surface

During green wavelength femtosecond laser ablation, d-band electrons are excited to become free and to participate in the absorption process. The increased electron temperature also induces the density of state shift and causes the gap between the d-band and the Fermi level to expand. The d-band electron transition effect during the laser ablation process causes nonlinear absorption, therefore, it should always be considered during simulations of laser-copper interaction.This study used a single femtosecond laser pulse with a wavelength of 515 nm and a pulse duration of 300 fs to ablate copper with fluence 0.7 - 63 J/cm2. The experimental results were compared with the theoretical results, where a modified Drude-critical point model was adopted to simulate the ablation depth. The modified model considered the electron transition effect and a two-temperature model that assumed both the linear and nonlinear absorption effect. Comparison of the experimental and simulated results revealed that the simulated ablation depth obtained using the nonlinear absorption model was consistent with the experimental results.

Research on double-faced jacquard fabric with compound full-backed structure of three wefts

Weft-backed structures with compound weft colours can express the mixed colour effect. However, this structure is not suitable for jacquard fabrics with a double-faced shading effect in the traditional single layer design mode. Taking twenty-thread sateen with a step number (S) of 7 as an example, this paper investigates a design method for compound full-backed structure with three shaded-weave databases (SWDs) by selecting the primary weaves (PWs), designing the compound full-backed technical points and establishing the compound structure database with three SWDs. With this design method, a double-faced shading effect in combination with non-backed and full-backed effects on different sides of the jacquard fabric at the same position is generated. The fabric colour card was produced with three SWDs and three sets of different coloured wefts, and their colour values were measured, followed by an analysis of the compound structures on the reverse side, lightness, colour purity and colour difference (DE*ab) of the specimens. The results showed that the three covering effects on the reverse side, partly covered, critical position and totally covered, could be adjusted by controlling the step number and the transition direction of PW-C. For the specimens on the edges of the fabric colour card, their lightness and colour purity values showed a uniform transition effect along with the shading process; their colour differences ranged from 1.23 to 3.69, both in the range of 2–5, and showed a trace or slight colour difference between two adjacent fabric specimens, indicating that the colour shading effect with the three SWDs is stable.

IFRS 9 Transition Effect on Financial Stability of Kosovo Commercial Banks

From January 1, 2018, most of the commercial banks in Kosovo adopted IFRS 9. The new standard introduces the expected credit loss model to allow for timely recognition of credit losses, estimated not only on the actual credit loss but also on forward-looking information regarding the current loan portfolio. Although, transition phases may lead to increasing impairments and a decrease in banks’ equity, which directly influences the financial stability of banks. This paper examines the day-one transition effect of IFRS 9 on the level of assets balance, allowance for loan losses, and capital regulatory class II of banks in Kosovo. To test our hypothesis, we have performed a comparative analysis for the six biggest commercial banks in Kosovo to identify correlation and causality between studied variables. As a statistical technique, we have employed a “paired sample t-test” where we compare financial indicators before and after adopting IFRS 9 to examine the impact on financial stability for commercial banks in Kosovo. Our results are in line with the results of recent studies in the IFRS 9 field and conclude that the transition phase has a significant influence on the recognition of additional loan impairment but assets and capital regulations are not affected significantly. Results demonstrate the transition to IFRS 9 causes instability and re-consolidation of capital, but in the long-run reduce the possibility for large and sudden losses. Commercial banks in Kosovo should follow a balanced growth approach without compromising the quality of the loan portfolio.

Analysis on Space accessibility of Medical Service Facilities in Central Wuhan Based on Improvement of 2SFCA

Aiming at the current imperfect hierarchical diagnosis and treatment system and the unreasonable spatial distribution of medical facilities. This article introduces 2SFCA model improved by the Gaussian distance decay function and multiple stage radius to evaluate the accessibility of medical facilities in Wuhan. The results indicate that: firstly, compared with the traditional 2SFCA model, the improved 2SFCA model is more sensitive to the identification of spatial accessibility, and the transition effect of the identification results is more obvious, which can accurately reflect the spatial distribution characteristics of the accessibility of medical facilities in Wuhan. Secondly, the distribution of medical facilities in Wuhan is obvious and the main factors that affect the accessibility value in different urban areas are quite different. Thirdly, the high value areas of medical facilities in the main urban area of Wuhan are mainly concentrated within the second ring line, the transition effect between the second and third ring lines is obvious, and the low value areas are mainly concentrated outside the third ring line. In the end, the main reasons for the low accessibility of the area outside the Third Ring Road are the low service quantity and low service ability of the community health service institutions and the high traffic resistance. The research results can provide a reference for the layout and planning of medical institutions in the main urban area of Wuhan.