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Affected by climate and natural conditions, cruise activities have obvious seasonal characteristics. For a cruise ship, seasonality consists of the systematic, although not necessarily regular, movement of a cruise ship in a selected time. To examine more specifically the natural factors of the seasonal characteristics from a microscopic perspective, we construct month-temperature, quarter-season, and year-climate zone, a seasonal analysis framework in two dimensions of space and time and using a single world cruise ship named Queen Elizabeth (QE) as the case. Comparing the characteristics of the trajectory network with the seasonal factors, we find the cruise ship tend to voyage in a stable temperature range of 10°C–20°C, flee the winter and catch up with the summer and spring, and mainly stay in the temperature maritime climate zone, the subtropical monsoon humid climate zone, and the Mediterranean climate zone to form several branch network. Finally, the academic and practical implications of the research findings for seasonal management and itinerary choice are elaborated from the supply-side and demand-side. [ABSTRACT FROM AUTHOR]

Spatial models of port system evolution often depict linearly the emergence of hierarchy through successive concentration phases of originally scattered ports. The Chinese case provides a fertile ground for complementing existing works by a long-term perspective, given the early importance of river ports and seaports and the development irregularities caused by periods of closure and openness over time and across such a large land mass. In both qualitative and quantitative ways, this paper describes and analyses the changing spatial pattern of China's port system since the first unified empire (221 bc). Main results underline a certain stability of the port system with regard to the location of main sea-river gateways, notwithstanding important regional shifts from one period to the other. [ABSTRACT FROM AUTHOR]

• Binding interactions between HA and TET inhibited the degradation of TET. • The nature of sites engaged in the HA/TET binding were identified by FTIR and 1H NMR analyses. • Degradation priority was established as free TET>bound TET>HA in UV/PMS, UV/H 2 O 2 and UV systems. • •OH/•SO 4 −, PMS and UV had varying roles in UV/PS, UV/PMS and UV/H 2 O 2 processes. The binding between dissolved organic matter (DOM) and micro-pollutants (MPs) results in significant impacts on their migration, transformation and degradation. However, the role of the DOM/MP binding on their oxidative transformation remains poorly studied. The binding of MPs by DOM, in combination with DOM's roles as a photosensitizer and/or a competitor for free radicals, needs to be considered in the context of understanding the DOM's impacts on the oxidative degradation of MPs. This study aims to explore this aspect of DOM/MP interactions based on the quantitation of humic acid (HA) and tetracycline (TET) complexation and its role in TET removal. This study also compared the degradation of free TET versus that bound in HA-TET complexes in different oxidation processes. Fourier transform infrared (FTIR) data show that the carboxyl and phenolic hydroxyl groups in HA are the main binding sites of TET, while nuclear magnetic resonance (NMR) analysis shows the binding of TET engages its -N(CH 3) 2 groups, and two-dimensional correlation spectroscopy (2D-COS) data show that the carboxyl groups in DOM are sensitive than phenolic groups in the binding of TET. The difference between the degradation rates (Δk obs) of the free and bound TET decreased with the increase of ionic strength using sodium nitrate, but increased with the introduction of Ca2+ and Mg2+ due to the formation of TET-Ca2+/Mg2+ complexes. Quenching experiments showed that the free radicals (•OH and •SO 4 −), PMS oxidant and UV light were the main contributors to the TET degradation in UV/PS, UV/PMS and UV/H 2 O 2 processes, respectively. In-situ fluorescence time scanning and differential absorbance spectra showed that free TET was preferentially oxidized over the bound TET in all the tested treatments except UV/PS. These results provide new insights into the role of DOM/MP complexation in the degradation of MPs in natural and engineered systems. [Display omitted] [ABSTRACT FROM AUTHOR]

• SO 4 •– acted as the dominant radical while •OH and 1O 2 were minor contributors. • SO 4 •– could be generated via DO-dependent or DO-independent way. • Crucial roles of •O 2 – in the sulfate radical-generating process were explored. • Vulnerable sites of BPAF molecule were evaluated by DFT analysis using Fukui index. • The removal pathway of BPAF was systematically investigated using MS and DFT. Though natural reducing agents have been demonstrated as desirable catalysts for environmental remediation, the mechanism of catalytic activation of persulfate (PS) by bisulfite (S(IV)) remains unclear. In this study, an emerging contaminant bisphenol AF (BPAF) was employed as the target compound to examine the activation and degradation mechanism in PS/S(IV) system. Sulfate radical (SO 4 •–) was evidenced as the dominant radical accounting for BPAF degradation via quantitative analysis, while hydroxyl radical (•OH) and singlet oxygen (1O 2) were minor contributors. Superoxide radical (O 2 •–) was identified as an intermediate radical in promoting BPAF removal through quenching experiments and electron paramagnetic resonance analysis. Tests in oxygen-rich and oxygen-deficient systems were conducted and the results were contrasted to elucidate the important role of oxygen in BPAF degradation and SO 4 •–-formation. In addition, the effect of Dissolved Oxygen (DO) was simulated using two separate kinetic models. Decomposition mechanism of BPAF was afterwards clarified via the density-functional theory calculations using Fukui index to predict the vulnerable sites and the intermediate products. This study provides a mechanistic understanding of the activation of PS/S(IV) system on the BPAF removal, especially the critical role of DO and O 2 •– in SO 4 •– generation. [ABSTRACT FROM AUTHOR]

Drinking water treatment using UV/H 2 O 2 advanced oxidation typically results in residual H 2 O 2 that requires quenching to minimize its interference with downstream processes. Chemical quenching using chlorine or bisulfite are options, but there is some uncertainty in the literature about the kinetics of the bisulfite reaction, with some reports quoting the reaction as fast, and others as slow. Part of the contradictory information may be due to interference in H 2 O 2 analysis by bisulfite. An analytical method was developed to avoid this interference, in which monochloramine first selectively quenched bisulfite, and then H 2 O 2 was measured spectrometrically using titanium(IV) oxysulfate for color development. The confirmatory experiments suggested that the bisulfite reaction with H 2 O 2 is actually relatively slow, with a half-life in the order of hours to days depending on the pH and the reagent concentrations. As a result, within the typical pH range of drinking water treatment (e.g., 6–9), chlorine is preferred over bisulfite as the H 2 O 2 quenching agent on the basis of reaction kinetics. However, a decrease in pH will lead to an increase in the bisulfite-H 2 O 2 reaction rate along with a decrease in the Cl 2 –H 2 O 2 reaction rate, such that at pH < 5.7 bisulfite is the faster reagent. Both bisulfite and chlorine were observed to react with H 2 O 2 following a stoichiometric ratio of 1:1 in the natural water matrix tested. Image 1 • Bisulfite quenches H 2 O 2 at too slow a rate to serve as a quenching agent. • Cl 2 quenches H 2 O 2 quickly at neutral and basic pH, but not instantaneously. • A modified titanium(IV) method was developed to quantify H 2 O 2. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel method for efficient and stable laser cutting of silicon by optimizing focusing condition is proposed. • Effect of focusing condition on laser underwater cutting property is discussed. • Effect of focusing condition on bubble behaviors is studied based on time-resolved imaging system. • Mechanism of focusing condition on transmission efficiency of laser is analyzed. In this paper, the effect and mechanism of how varying focusing conditions would affect the machining quality of microgrooves and bubble behaviors (cavitation bubbles (CB) and persistent bubbles (PB)) in liquid-assisted femtosecond laser micro-grooving of silicon wafer were investigated. Firstly, the width and depth of the microgroove machined under negative defocusing condition (NDC) were considerably uniform, which showed an increase by 100 % and 125 % compared with that machined under positive defocusing condition (PDC). Secondly, the temporal evolution images of CB were captured by a time-resolved shadowgraph imaging system. Compared with PDC, the radius and lifetime of CB induced under NDC increased by 71 % and 100 %, and the time evolution curve of the radius of CB exhibited a high consistence with the Rayleigh distribution, while that induced under PDC fluctuated irregularly. Thirdly, the PB induced under NDC showed a backward flush and contributed to the formation of tendentious liquid flow, while that induced under PDC occupied the laser transmission path and caused disturbances on subsequent laser pulses. Finally, the differences in laser transmission mechanism under both the negative and positive defocusing conditions were discussed and the NDC was confirmed as the stable and efficient processing method. Through the comprehensive study of the bubble behaviors, the correlation between focusing conditions and machining quality of liquid-assisted laser cutting was established. [ABSTRACT FROM AUTHOR]

The machining of sapphire, a hard and transparent material, is of significant interest in various industries due to its exceptional properties. Traditional machining methods for sapphire suffer from drawbacks such as low efficiency and poor processing quality. Laser machining, particularly using ultraviolet (UV) nanosecond lasers, has emerged as a promising alternative for machining sapphire. In this article, we explored the use of reflective target materials to enhance laser energy absorption during the machining of sapphire. The effect of different reflective target materials, including aluminum and silicon, on the laser machining process was examined. Parametric calculations and finite-difference time-domain (FDTD) simulation were performed to evaluate the laser intensity at the top surface of sapphire when a reflective target material was employed. The results demonstrated that the use of reflective target materials leads to increased laser intensity due to the interference of incident and reflected laser beams, thus improving material removal efficiency. Moreover, experimental observations confirmed the effectiveness of using reflective target materials in enhancing the machined depth of sapphire. For example, the machined depth of 21.6 µm with a power density of 1.7 × 108 W/cm2 increased to 23.3 µm and 26.5 µm by using silicon and aluminum target materials. It is found that using aluminum target led to higher machined depth than silicon owing to its higher reflectivity. • Employing reflective target materials to enhance material removal efficiency in the ultraviolet (UV) nanosecond laser machining of sapphire. • Understanding the relationship between laser intensity and the refractive indices of the target material and sapphire substrate. • Evaluating the laser intensity at the top surface of sapphire by using parametric calculations, finite-difference time-domain (FDTD) simulations, and experimental observations. [ABSTRACT FROM AUTHOR]

With the popularization of computers, artificial intelligence technology has become more and more mature, among which speech recognition technology in artificial intelligence is favored by people. In the past few years, the acoustic model combined with the Gaussian mixture model and the hidden Markov model has always been in the leading position. In the field of speech recognition technology, because the development of speech data has gradually expanded, and the complexity of the data has also increased. The larger the data, the traditional data network model is slowly showing inadequacy. However, the deep neural network model is easy to deal with large and complex data modeling. This article combines the advantages of basic learning theory and speech recognition technology, and launches in-depth research on embedding learning theoretical knowledge into the field of speech recognition. Nowadays, large-scale text information databases relying on computers are becoming more and more important in linguistic research, and a large-scale corpus that fully reflects language facts and contains rich language information has been constructed. The establishment of the text information database system is long, from word segmentation, part-of-speech tagging to syntactic tagging to semantic tagging. Therefore, the characteristic of information system processing is that the systematic description depends on the application environment of understanding vocabulary and reasoning. According to different scenarios, the realization methods of semantic description roles are also different, and the description of semantic roles in correct scenarios is clearer, more detailed and systematic. Therefore, this article is of great significance for solving the semantic problem of using Chinese frame network for Chinese information processing in the context of speech recognition. [ABSTRACT FROM AUTHOR]