桐油改性双环戊二烯不饱和树脂的合成及其性能研究

采用催化水解加成法合成了桐油改性双环戊二烯不饱和聚酯,通过对桐油滴加前后不饱和聚酯的凝胶色谱及红外表征,证实了桐油与不饱和聚酯分子链中的双键发生了Diels-Alder反应。研究了桐油加入量对树脂涂膜的气干性、附着力、柔韧性、硬度、耐磨性及树脂耐热性能的影响,并确定了桐油的最佳加入量。结果表明:较未改性的双环戊二烯不饱和聚酯(DCPD-UPR),桐油基DCPD-UPR的涂膜具有更好的气干性、柔韧性、粘接性和耐磨性,并且桐油基DCPD-UPR的耐热性也优于未改性的DCPD-UPR。     

双膜系统在化工废水深度处理中的应用

云天化股份有限公司废水深度处理及回用工程采用UF+RO双膜工艺,处理后的产品水作为生产水回用。实际运行结果表明,UF+RO双膜工艺能有效去除污水中的有机物、SS和各种阴阳离子。出水水质能够达到炼油企业污水回用管理规范中"优质工业再生水水质指标",从而节约大量新水,产生了良好的经济效益和环境效益。     

随机模糊优化问题合适解的存在性

本文讨论了随机模糊优化问题合适解的存在性,指出了两种影响合适解存在的情况,并建议了一种调整合适解存在性的办法.当随机模糊优化问题是一个凸模糊优化问题时,本文还根据凸模糊集合分离度的概念,讨论了对目标和约束的最大合适度要求的存在性,及对目标和约束同时具有最大的合适度要求的存在性.     

Experimental study on mix proportion and fresh properties of fly ash based geopolymer for 3D concrete printing

This paper presents the material design and fresh properties of geopolymer mortar developed for 3D concrete printing application. Unlike traditional casting, in 3D printing, extruded materials are deposited layer-by-layer to build complex architectural and structural components without the need of any formwork and human intervention. Extrudability, shape retention, buildability and thixotropic open time (TOT) are identified as critical early-age properties to characterize the 3D printable geopolymer material. Five different mix designs of geopolymer are tested in a systematic experimental approach to obtain a best printable mix and later it is used to print a 60-centimeter-tall freeform structure using a concrete gantry printer to validate the formulation.     

Effect of microwave sintering on the properties of copper oxide doped Y-TZP ceramics

The effect of various amounts of copper oxide (CuO) up to 1?wt% on the densification behaviour and mechanical properties of 3?mol% yttria-tetragonal zirconia polycrystal (Y-TZP) were studied by using microwave (MW) sintering method. The MW sintering was performed at temperatures between 1100?°C and 1400?°C, with a heating rate of 30?°C/min. and holding time of 5?min. The beneficial effect of MW in enhancing densification was also compared for the undoped and 0.2?wt% CuO-doped Y-TZP when subjected to conventional sintering (CS) method. The results showed that significant enhancement in the relative density and Vickers hardness were observed for the undoped Y-TZP when MW-sintered between 1100?°C and 1250?°C. It was revealed that the 0.2?wt% CuO-doped Y-TZP and MW sintered at 1250–1300?°C could attain ≥?99.8% of theoretical density, Vickers hardness of about 14.4?GPa, fracture toughness of 7.8 MPam^1/2 and exhibited fine equiaxed tetragonal grain size of below 0.25?µm. In contrast, the addition of 1?wt% CuO was detrimental and the samples exhibited about 50% monoclinic phase upon sintering coupled with poor bulk density and mechanical properties. The study also revealed that the addition of 0.2?wt% CuO and subjected to conventional sintering produced similar densification as that obtained for microwave sintering, thus indicating that the dopant played a more significant role than the sintering method.     

Hierarchical carbon nanotube membrane with high packing density and tunable porous structure for high voltage supercapacitors

We reported the fabrication of a hierarchical carbon nanotube (CNT) membrane by using the 90% granulated double- or triple-walled CNTs and 10% 100 μm long multiwalled CNTs as the linker. The membrane with packing density of 420 kg/m³, excellent electrical conductance and good mechanical strength, functioned as both the electrode and current collector and allowed the weight ratio of CNTs increased up to 45–50% based on the weight of CNT, electrolyte and separator. The granulated double or triple walled CNTs, by the aggregation at high temperature etching using CO₂, simultaneously exhibited high surface area and tunable pore structure and high pore volume, and were favorable for the ion transport of organic electrolyte, due to the effect of opening cap or side wall by the CO₂. The CNT membrane electrode, exhibited the capacitance of 57.9 F/g and the energy density of 35 W h/kg, as operated at 4 V.     

Crystallization behavior,heat resistance,and mechanical performances of PLLA/myo‐inositol blends

In this work, use of myo‐inositol as a biobased nucleating agent (NA) for PLLA was researched. Effects of myo‐inositol on non‐isothermal and isothermal crystallization behaviors of PLLA at temperatures ranged from 85 °C to 130 °C were studied by using DSC, POM and WAXD. Isothermal crystallization kinetics results showed that the incorporation of myo‐inositol enhanced significantly the crystallization rate of the PLLA samples. It was confirmed that the optimum isothermal crystallization temperature range was 100 to 110 °C. The above results were instructive to confirm proper heat treatment time and temperature for compression or injection molding to fabricate highly crystallized PLLA articles. The relations among heat treatment time, crystallinity, heat resistance, and mechanical performances of the neat PLLA and PLLA/1% myo‐inositol specimens prepared by compression molding were investigated. Compared with the PLLA specimens, the PLLA/1% myo‐inositol specimens showed a shorter heat treatment time to reach the maximum crystallinity. Vicat softening temperature, as well as tensile strength, modulus, and toughness of the PLLA/1% myo‐inositol specimens was improved when crystallinity increased from 5.4% to 38.1%. Considering the nontoxicity and biocompatibility of myo‐inositol, PLLA/myo‐inositol blends would be potential to prepare some products, which are required higher health standard and can be used in elevated temperature environments. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44732.     

Absorption of picoliter droplets by thin porous substrates

Absorption of picoliter (pL) droplets into porous substrates is studied experimentally and numerically. In the case of pL droplets, major phenomena involved in the interaction between droplet and porous media develop at different time scales: spreading and wetting at microseconds, absorption and wicking at milliseconds, and evaporation at seconds. Therefore, one can decouple these processes to minimize the complexity of the study. A high‐speed imaging system capable of 1 million frames per second is used to visualize individual droplets impacting, spreading, and imbibing on substrates. To simulate droplet dynamics, the governing equations for flow outside and inside porous media are proposed and solved using an in‐house developed computational fluid dynamics solver. The simulation results are in good agreement with the experimental data. The effect of drop impact velocity and fluid properties on final dot shape in the porous substrates is investigated through a series of parametric numerical studies. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1690–1703, 2017     

Cocoa Butter Substitute (CBS) Produced from Palm Mid-fraction/Palm Kernel Oil/Palm Stearin for Confectionery Fillings

This study investigated the physicochemical properties of ternary mixtures of palm mid-fraction (PMF):refined bleached deodorized palm kernel oil (RBDPKO):refined bleached deodorized palm stearin (RBDPS) for cocoa butter substitute (CBS). Fatty acid constituents, triacylglycerol constituents, solid fat contents (SFCs), melting behavior, polymorphism and crystal morphology were determined using gas chromatography (GC), high-performance liquid chromatography (HPLC), differential scanning calorimetry (DSC), pulsed nuclear magnetic resonance (p-NMR), X-ray diffraction (XRD) and polarized light microscopy (PLM), respectively. Eight blends of various ratios of ternary mixtures were investigated based on the previously studied binary fat mixtures. The composition of palmitic (P) and oleic (O), POP, and crystal morphology (size and shape) of the PMF/RBDPKO/RBDPS [14.9/59.6/25.5 (%w/w)] mixture were comparable to cocoa butter (CB), while its melting profile (18.5 and 37 °C), SFC at 20 °C and polymorphism were different from CB. The iso-solid diagrams of the mixture displayed a monotectic effect at 20–25 °C. Therefore, the 14.9/59.6/25.5 PMF/RBDPKO/RBDPS mixture could be used as a CBS in confectionery fillings because of the crystal morphology and monotectic behaviors comparable to those of CB.     

Recovery and partial purification of thermophilic β-xylosidase derived from recombinant Bacillus megaterium MS941 by aqueous two-phase system

A polymer–salt-based aqueous two-phase system (ATPS) was developed for the effective extraction and purification of extracellular β-xylosidase from the fermentation broth of recombinant Bacillus megaterium MS941. The effect of molecular weight (MW) of polyethylene glycol (PEG), tie-line length (TLL), volume ratio (V_R), crude loading and pH on the recovery performance was evaluated. Under the optimal extraction conditions, β-xylosidase was successfully purified up to 23-fold with a recovery yield of 99% in the bottom salt-rich phase at PEG 4,000/potassium phosphate ATPS comprising TLL of 41.8, V_R of 2.3, crude loading (C_L) of 30% (w/w) at pH 6.