AZ31B镁合金板材中晶界滑移的晶体塑性仿真

建立一种耦合滑移、动态再结晶以及晶界滑移的晶体塑性模型以仿真镁合金的高温变形行为及织构演化.首先,通过实验测量单轴拉伸、压缩后的织构以及显微组织演化,研究AZ31B镁合金在300°C的变形机制.结果发现,动态再结晶在应变小于0.2时起到细化晶粒的作用,之后晶界滑移在变形过程中起显著作用.此外,建立晶界滑移模型来评估由晶...     

Textile applications of photochromic dyes. Part 5: application of commercial photochromic dyes to polyester fabric by a solvent‐based dyeing method

A series of commercial photochromic dyes was applied to polyester by a solvent dyeing process followed by thermal fixation using dichloromethane as the solvent. The process was optimised in terms of solvent/fabric ratio, dye concentration and the conditions of thermal fixation. The dyed fabrics showed reversible photochromism, developing colour on ultraviolet exposure and fading after removal of the ultraviolet source. The degree of photocoloration, background colours, fading characteristics, fatigue resistance and storage stability of the dyes were evaluated and comparisons made with the outcomes of a traditional aqueous disperse dyeing method. A study of the visible spectra of concentrated solutions of the dyes in a range of solvents provided evidence for the origin of the permanent background colours on the fabric when applied from solvents. Relationships were established between the magnitudes of the visible absorption in solution and the background colours developed, in relation to the nature of the solvents. The results suggest that toluene and ethyl acetate may offer certain advantages as solvents for the application of these dyes.     

Effects of cobalt and cobalt oxide buffer layers on nucleation and growth of hot filament chemical vapor deposition diamond films on silicon (100)

An initial study on the nucleation and growth of diamond, using hot filament chemical vapor deposition (HFCVD) technique, was carried out on Co and CoO thin buffer layers on non-carbon substrates (Si (100)), and the results were compared with conventional scratching method. The substrate temperature during the growth was maintained at 750±50 °C. A mixture of CH₄ and H₂ (1: 100 volume %) was used for deposition. The total pressure during the two hour deposition was 30±2 Torr. X-ray photoelectron spectroscopy (XPS) study showed the diamond nucleation at different time periods on the Co and CoO seed layers. It is observed that Co helps in nucleation of diamond even though it is known to degrade the quality of diamond film on W-C substrate. The reason for improvement in our study is attributed to (i) the low content of Co (~0.01%) compared to W-C substrate (~5–6%), (ii) formation of CoSi₂ phase at elevated temperature, which might work as nucleation sites for diamond. SEM analysis reveals a change in the morphology of diamond film grown on cobalt oxide and a significant reduction in the size of densely packed crystallites. Raman spectroscopic analysis further suggests an improvement in the quality of the film grown on CoO buffer layer.     

Synthesis and application of novel tricyanofuran hydrazone dyes as sensors for detection of microbes

Acknowledging the need to develop rapid and sensitive bacterial recognition approaches, we functionalised the tricyanofuran hydrazone molecular switch. Of significant interest in relation to the synthesised hydrazones is the formation of two different conjugated structures upon exposure to different pH values. Many bacteria release ammonia gas, which alkalises environments. Herein we report the synthesis of a tricyanofuran hydrazone having the function of a colorimetric pH sensor. The UV‐visible absorption and fluorescence spectra exhibit reversible colour changes of the tricyanofuran hydrazone solution in acetonitrile under acid–base conditions. Our results indicate that the tricyanofuran hydrazone probe can identify the bacterial targets quickly with high sensitivity. The infected samples exhibit a significant colour change from orange to blue and in the mean time there is a decrease in fluorescence emission as a function of ammonia and volatile amines released from bacterial metabolites. This tricyanofuran hydrazone chromophore is proposed for use in food packaging with a pH‐sensing capability.     

Evaluation of the Suitability of Agriglasses Containing ZnO for Plant Fertilization

Six different samples from borosilicate and phosphate glassy systems have been synthesized. Glass batches were prepared from chemically pure materials and melted in platinum or porcelain crucibles and at temperatures in the range 1,000–1,450 °C for 2-3 h until homogeneity was reached. The prepared specimens were annealed at the appropriate temperatures of 380 or 520 °C for the phosphate and borosilicate glasses, respectively. Samples of 2 mm dimensions were tested for dissolution behavior in 2% citric acid solution for 1, 2, 3, and 4 weeks and the released phosphorous and potassium ions (macroelements) and zinc ions (microelement) were measured. Also, Infrared (IR) absorption spectra of the samples were measured before and after immersion in the leaching solution. The experimental results indicate that the release of the macroelements and microelements depends primarily on the composition of the agriglass and the percent of constituent ions and the released ions vary slightly from 1 week to 4 weeks. The IR spectra show characteristic IR absorption bands due to vibrations of collective silicate, phosphate, and borate groups, depending on the agriglass composition and the chains or units seem to be interconnected with each other within the glass network. The interpretation of the dissolution behavior is based on a suggested mechanism for the release of the easily soluble components from the glass specimens. The IR absorption spectra support and confirm the proposed behaviour for the corrosion mechanism.     

Investigation on the mixture formation,combustion characteristics and performance of a Diesel engine fueled with Diesel,Biodiesel B20 and hydrogen addition

An experimental and numerical study was performed to investigate the impact of Biodiesel B20 (blends 20% Rapeseed methyl ester with 80 % Diesel volumetric fraction) and different energetic fractions of hydrogen content (between 0 and 5%) on the mixture formation, combustion characteristics, engine performance and pollutant emissions formation. Experiments were carried out on a tractor Diesel engine, four-cylinders, four-stroke, 50 kW/2400 rpm, and direct injection. Simulations were conducted using the AVL codes (HYDSIM and BOOST 2013). Simulation results were validated against experimental data, by comparing the inline pressure, needle lift, in-cylinder pressure curves for Biodiesel B20 and pure Diesel fuels at 1400 rpm and 2400 rpm, respectively, under full load operating conditions. Good agreement with a maximum of 2.5% relative deviation on the peak results revealed that overall operation conditions Biodiesel B20 provides lower engine performance, efficiency, and emissions except the NOx which are slightly increased. The Biodiesel B20 has shorter ignition delay. By hydrogen addition to B20 with aspiration of the intake air flow the CO emissions, smoke, and total unburned hydrocarbon emissions THC decreased, while the NOx kept the same increasing trend for 1400 rpm and has not quite apparent trend for 2400 rpm. The enrichment by hydrogen of Diesel and B20 fuels has not a significant effect on ignition delay.     

Endometrium Immunomodulation to Prevent Recurrent Implantation Failure in Assisted Reproductive Technology

After more than four decades of assisted reproductive technology (ART) practice worldwide, today more than 60% of women undergoing in vitro fertilization (IVF) treatments fail to become pregnant after the first embryo transfer and nearly 20% of patients are suffering from unexplained recurrent implantation failures (RIFs) and repeated pregnancy loss (RPL). The literature reported different causes of RIF–RPL, mainly multifactorial, endometrial and idiopathic. RIF remains a black box because of the complicated categorization and causes of this physio-pathological dysregulation of implantation and pregnancy process after ovarian stimulation. Many options were suggested as solutions to treat RIF–RPL with controversial results on their usefulness. In this article, we reviewed different possible therapeutic options to improve implantation rates and clinical outcomes. Based on our experience we believe that endometrium immunomodulation after intrauterine insemination of activated autologous peripheral blood mononuclear cells (PBMCs) or platelet-rich plasma (PRP) can be a promising therapeutic solution. On the other hand, peripheral lymphocyte balance typing, specific cytokines and interleukins profiling can be proposed as predictive biomarkers of implantation before embryo transfer.     

Potential Antigenic Candidates for the Development of Peptide-Based Vaccines to Induce Immunization against Helicobacter pylori Infection in BALB/c Mice

Helicobacter pylori (H. pylori) has been identified as a group-1 definite carcinogen. As of yet, there is no available vaccine for this microorganism. Our study aimed to identify antigenic peptides in H. pylori using an in silico proteomic approach, and to evaluate their effectiveness as potential vaccine candidates. Four different peptide sequences were prioritized using the reverse vaccinology, namely, CagA¹, CagA², VacA, and SabA. Peptides emulsified with Freunde’s adjuvant were used to immunize BALB/C mice. Subcutaneously immunized mice were challenged by oral administration of H. pylori. IgG, IgA, IL4, and IL17 were detected in mice sera. Histopathology of the dissected stomach of vaccinated and control mice were assessed using H&E stain. IgG was significantly higher in mice vaccinated with SabA. IL-4 was significantly increased in CagA¹, CagA², VacA, and SabA vaccinated mice compared to the adjuvant group. Additionally, histopathological examination of gastric tissue showed a protective effect in the vaccinated groups compared to adjuvant and PBS groups. Our findings indicate a promising effect of the tested epitopes, particularly the SabA antigen, to induce an immune response against H. pylori.