Synthesis,structure identification and linear/nonlinear optics of hydrothermally grown WO3 nanostructured thin film/FTO: Novel approach

Thin film of WO₃ has been deposited on conductive fluorine tin oxide substrate using the hydrothermal technique. The film's microstructural, morphological and optical properties have been identified using X-ray diffraction, atomic force microscope, and spectrophotometer. The obtained results have confirmed the nanocrystalline structure of the as-received WO₃ thin film with crystallite size ≈63.4 nm. Analysis of the absorption coefficient using Tauc's model shows the possibility of direct and/or indirect allowed transition with energy gaps 3.95 and/or 3.45 eV, respectively. The refractive index has been determined by different methods showing the average value (2.2 and 2.3 corresponding to the direct and indirect transitions, respectively). The nonlinear refractive index and third-order nonlinear optical susceptibility have been determined, showing the high polarizability of WO₃/FTO with radiation to be promising for different optical devices and applications.     

Tribological performance of UV picosecond laser multi-scale composite textures for C/SiC mechanical seals: Theoretical analysis and experimental verification

The performance of mechanical seals can be improved by using multi-scale composite textures with spiral grooves and micro-dimples, but without a clear texture function mechanism, it is difficult to optimize the textures on the sealing surface. This research established a mathematical model based on the mass-conservative JFO cavitation boundary to analyze the mechanical seal performance of multi-scale composite micro-textures. We use the multi-grid method for numerical solutions, investigate the hydrodynamic lubrication characteristics of composite-textured mechanical seals, and inspect the coupling effect of micro-dimples and spiral grooves. We also analyzed the influence of the geometrical parameters of composite textures on the sealing performance and optimized the sealing surface textures using theoretical analysis. The numerical analysis showed that the multi-scale composite-textured mechanical seal produced a coupling effect between the micro-dimples and spiral grooves, which improved the lubrication of the sealing pair. Eventually, C/SiC mechanical seal bench tests confirmed the tribological improvement of composite textures compared with the un-textured seal under various sealing liquid pressures and rotation speeds. Through comparing the Stribeck curve, the multi-scale composite textured C/SiC mechanical seals have a lower and more stable friction torque than the un-textured.     

富芳烃重油组分结构调变对中间相沥青形成的影响机制

对重油富芳烃组分转化为次生沥青及其氢化改性沥青的热转化行为进行了比较，并对热转化过程中体系化学结构组成特征对中间相形成的影响进行了研究。采用红外光谱及氢核磁共振波谱，对比分析了次生沥青及其氢化改性沥青的化学结构组成特征；借助偏光显微镜、X射线衍射，考察了两体系中间相沥青的形成过程。结果表明：控制体系短烷基侧链含量可有效抑制过度炭化的发生，提高炭化产物的微观有序度；短烷基侧链可以持续稳定释放出小分子自由基，对大分子自由基反应进行调控，显著提升炭化产物微观结构的均一性。     

Suppressed Lattice Disorder for Large Emission Enhancement and Structural Robustness in Hybrid Lead Iodide Perovskite Discovered by High-Pressure Isotope Effect

The soft nature of organic–inorganic halide perovskites renders their lattice particularly tunable to external stimuli such as pressure, undoubtedly offering an effective way to modify their structure for extraordinary optoelectronic properties. Here, using the methylammonium lead iodide as a representative exploratory platform, it is observed that the pressure-driven lattice disorder can be significantly suppressed via hydrogen isotope effect, which is crucial for better optical and mechanical properties previously unattainable. By a comprehensive in situ neutron/synchrotron-based analysis and optical characterizations, a remarkable photoluminescence (PL) enhancement by threefold is convinced in deuterated CD₃ND₃PbI₃, which also shows much greater structural robustness with retainable PL after high peak-pressure compression–decompression cycle. With the first-principles calculations, an atomic level understanding of the strong correlation among the organic sublattice and lead iodide octahedral framework and structural photonics is proposed, where the less dynamic CD₃ND₃⁺ cations are vital to maintain the long-range crystalline order through steric and Coulombic interactions. These results also show that CD₃ND₃PbI₃-based solar cell has comparable photovoltaic performance as CH₃NH₃PbI₃-based device but exhibits considerably slower degradation behavior, thus representing a paradigm by suggesting isotope-functionalized perovskite materials for better materials-by-design and more stable photovoltaic application.     

粮油食品防霉微生物筛选及其活性物质初步研究

为开发新型防霉剂，降低粮油食品储藏、运输、流通等过程中霉变对其品质和食用安全的影响，研究筛选获得具有强防霉活性的微生物。采用抑菌圈法，以禾谷镰刀菌（Fusarium graminearum）为指示菌筛选具有防霉活性的菌株。利用形态学观察、生化特征鉴定和16S rDNA基因序列比对进行菌株鉴定；通过不同温度、pH和蛋白酶K处理对防霉活性物质进行初步分析。结果显示：通过初筛获得33株对禾谷镰刀菌具有强抑制活性的菌株，复筛后选择的7株菌归属为芽孢杆菌属（Bacillus）；活性物质分析发现7株菌的活性物质均不耐高温和强酸碱，同时蛋白酶K处理对其防霉效果没有明显影响，初步推断为肽类；通过抑菌谱测定发现菌株ASAG 62对常见霉菌（产黄青霉Penicillium flavum、黑曲霉Aspergillus Niger、赭曲霉Aspergillus ochre、黄曲霉Aspergillus flavus、禾谷镰刀菌F. graminearum）均具有良好的抑制效果。     

Finite difference analysis for entropy optimized flow of Casson fluid with thermo diffusion and diffusion-thermo effects

Heat transportation is a novel prospective in many thermal processes and presents dynamic applications in industrial and thermal polymer processing optimization. The importance of heat transportation is noted in heat exchangers, production of crude oils, combustion, petroleum reservoirs turbine systems, thermal systems, porous media, modeling of resin transfer nuclear reactions etc. In view of such thermal applications the main objective here is to examine entropy in unsteady magnetohydrodynamic of Casson fluid flow. Radiation in addition to dissipation and ohmic heating are analyzed. Entropy is scrutinized employing thermodynamic second law. Characteristics of Soret and Dufour are also examined. Main objective here is to examine irreversibility. Dimensionless version of differential system is obtained through suitable variables. The obtained partial differential system is solved through numerical scheme (Finite difference method). Physical features of fluid flow, temperature, entropy optimization and concentration have been explained. Variations of parameters on drag force, Nusselt number and solutal transfer rate are graphically discussed. Higher fluid parameter leads to improve in velocity and entropy rate. Larger values of radiation parameter boost up thermal field. Entropy rate and velocity have reverse trend for magnetic field. An intensification for concentration is found through Soret number. Higher approximation of Reynold number enhances skin friction and velocity. Thermal transfer rate is augmented versus radiation and magnetic variables.     

An innovative approach for geothermal-wind hybrid comprehensive energy system and hydrogen production modeling/process analysis

In this paper, the energy, exergy, economic, environmental, steady-state, and process performance modeling/analysis of hybrid renewable energy (RE) based multigeneration system is presented. Beyond the design/performance analysis of an innovative hybrid RE system, this study is novel as it proposes a new methodology for determining the overall process energy and exergy efficiency of multigeneration systems. This novel method integrates EnergPLAN simulation program with EES and Matlab. It considers both the steady-state and the process performance of the modeled system on hourly timesteps in order to determine the overall efficiencies. Based on the proposed new method, it is observed that the overall process thermodynamic efficiencies of a hybrid renewable energy-based multigeneration system are different from its steady-state efficiencies. The overall energy and exergy efficiencies reduce from 81.01% and 52.52% (in steady-state condition) to 58.6% and 39.33% (when considering a one-year process performance). The integration of the hot water production with the multigeneration system enhanced the overall thermodynamic efficiencies in steady-state conditions. The Kalina system produces a total work output of 1171 kW with a thermal and exergy efficiency of 12.23% and 52% respectively while the wind turbine system produces 1297 kW of electricity in steady-state condition and it has the same thermal/exergy efficiency (72%). The economic analysis showed that the Levelized cost of electricity (LCOE) of the geothermal energy-based Kalina system is 0.0103 $/kWh. The greenhouse gas emission reduction analysis showed that the proposed system will save between 1,411,480 kg/yr and 3,518,760 kg/yr of greenhouse gases from being emitted into the atmosphere yearly. The multigeneration system designed in this study will produce electricity, hydrogen, hot water, cooling effect, and freshwater. Also, battery electric vehicle charging is integrated with process performance analysis of the multigeneration system.     

保护层一次钻爆技术在三峡工程的研究与应用

从孔间、孔内双微差起爆和孔底设置柔性垫层分析“梯段炮孔加柔性垫层”的作用成因；从水平预裂和梯段孔深的确定分析“梯段炮孔加水平预裂”的作用成因，并通过试验及爆前、爆后检测和检查，说明这两种保护层一次钻爆技术理论上是可行的，在实践上很适合大中型水电工程保护层开挖。     

Low-temperature plasma modified Vulcan XC72R as a support to enhance the methanol oxidation performance of Pt nanoparticles

Vulcan XC72R as a kind of carbon material is widely used as a support to deposit metal catalysts. However, its low pore size, the difficulty of dispersion, and the rare sites have limited its application. In this work, we modified the surface of Vulcan XC72R by low-temperature plasma. It is detected that its original morphology and structure have been greatly changed by longtime plasma irradiation. The pore size increased and the specific surface area decreased with the increasing treatment time, while the pore volume initially increased and then decreased. Meanwhile, the outside surfaces of Vulcan XC72R were exfoliated to ultra-thin nanosheets and grafted with the oxygen-containing functional groups. Compared with the untreated Vulcan XC72R, Pt nanoparticles supported on treated Vulcan XC72R with smaller size exhibited higher catalyst activity and longer cyclic stability for the methanol oxidation reaction. This study demonstrates that plasma is an efficient approach to tuning the pore size and functionalizing the surface of Vulcan XC72R.     

Numerical investigation of thermal and electrical management during hydrogen reversible solid-state storage using a novel heat exchanger based on thermoelectric modules

In order to reduce the costs generated by the hydrogen solid storage tank's accessories such as the heat exchanger, this work was carried out. It shows thermal and electrical investigations of transient hydrogen (H₂) solid storage in a tank filled with porous medium (LaNi₅) to activate a potential PEM automotive fuel cell. For this purpose, we use a novel heat exchanger with a heat sink combined with thermoelectric modules (TEMs). We realize a simulation that helps us verify if thermoelectric exchanger will be an alternative to the conventional ones. The main results are that a thermoelectric cooler and heater with 127 couples of semiconductors coupled with 19 fins heat sink could be used during the reversible hydrogen solid storage. Also, results show that we can avoid the water freezing at negative temperatures when using a conventional heat exchanger by using TEM during hydrogen absorption. Finally, during the endothermic desorption of the hydrogen, TEG use can avoid boiling water used in the heating system. Also, the hydrogen tank will be lighter and compact without fins and water tubes.