活性炭在醋酸水溶液中对醋酸的吸附实验条件探索

通过活性炭在醋酸水溶液中对醋酸的吸附实验 ,确定合适的醋酸水溶液浓度范围和振荡时间等实验条件 ,该实验条件随实验温度变化而不同。用SA310 0表面积分析仪测定活性炭的比表面积 ,并与该方法测定的活性炭比表面积数值进行比较 ,分析了该实验方法产生误差的原因     

豆腐果苷-咪唑衍生物的合成及镇静活性研究

以豆腐果苷、2-羟基-1,2-二芳基乙酮(2a～2d)、乙酸铵和脂肪胺为原料,碘单质作为催化剂,成功地合成了一系列豆腐果苷-咪唑类衍生物4a～4h,新化合物4a～4h的结构经~1H NMR,~(13)C NMR,IR和HRMS确认.并用小白鼠实验对目标化合物4a～4h进行了镇静活性筛选,其中4e(400mg·kg~(-1))与豆腐果苷相比有较强的镇静活性.     

The effect of OCoAl‐LDH and OCoFe‐LDH on the combustion behaviors of polyvinyl chloride

The effects of the modified layered double hydroxide (LDH) of Co/Al (OCoAl‐LDH) and the modified LDH of Co/Fe (OCoFe‐LDH) on the combustion behaviors of polyvinyl chloride (PVC) during pyrolysis processes were compared and investigated. The thermal degradation and combustion behavior of the PVC composites were investigated by thermogravimetric analysis (TGA), microscale combustion calorimetry (MCC), and cone calorimetry (CONE). The results indicate that the incorporation of LDHs brought about the improved thermal stability and reduced heat release of PVC composites at a high temperature. The smoke‐suppression properties of the composites are investigated by steady‐state tube furnace (SSTF), and the results indicated that the toxic gases such as CH₄, CO, and N_xO were inhibited by both of the two LDHs, but the OCoFe‐LDH has a better effect on the smoke suppression. Subsequently, the char layer was investigated by scanning electron microscopy–energy‐dispersive spectrometry (SEM‐EDS) and Raman analysis. The results indicate that the LDHs can promote the dechlorination of PVC during the thermal oxidation process and can inhibit the production of HCl in inert gas. Generally, OCoAl‐LDH and OCoFe‐LDH can be potential catalysts for waste disposal and can improve the fire safety of PVC.     

Synergistic effect between solid wastes and intumescent flame retardant on flammability and smoke suppression of thermoplastic polyurethane composites

Phosphorus tailings and fly ash both are solid wastes and do harm to the environment. Here, they were added into thermoplastic polyurethane (TPU) matrices together with intumescent flame retardants (IFR), and the synergistic effects between IFR and phosphorus tailings or fly ash for improving the flame retardancy of TPU were investigated. The cone calorimeter test (CCT) results indicated that adding phosphorus tailings or fly ash substitute for part of IFR could obtain a better flame retardant effect. The peak heart release rate (PHRR) of TPU/25 wt% IFR composites exhibited a reduction of 77% than that of neat TPU, and the total smoke production presented a reduction of 16%. However, the PHRR value and total smoke production of the sample TPU/20 wt% IFR/5 wt% phosphorus tailings were reduced by 91% and 57%, respectively, compared to that of neat TPU. The dense char promoted by the presence of IFR and phosphorus tailings or fly ash delayed the diffusion of volatile pyrolysis products and transmission of heat and oxygen to the underlying material. Therefore, a certain amount of phosphorus tailings or fly ash can be used as synergistic agents with IFR to enhance the fire safety of TPU materials. From another aspect, it also provides a promising way for recycling use of phosphorus tailings and fly ash.     

Enhanced CO2 Electroreduction on Neighboring Zn/Co Monomers by Electronic Effect

It is of great significance to reveal the detailed mechanism of neighboring effects between monomers, as they could not only affect the intermediate bonding but also change the reaction pathway. This paper describes the electronic effect between neighboring Zn/Co monomers effectively promoting CO₂ electroreduction to CO. Zn and Co atoms coordinated on N doped carbon (ZnCoNC) show a CO faradaic efficiency of 93.2 % at ?0.5 V versus RHE during a 30‐hours test. Extended X‐ray absorption fine structure measurements (EXAFS) indicated no direct metal–metal bonding and X‐ray absorption near‐edge structure (XANES) showed the electronic effect between Zn/Co monomers. In situ attenuated total reflection‐infrared spectroscopy (ATR‐IR) and density functional theory (DFT) calculations further revealed that the electronic effect between Zn/Co enhanced the *COOH intermediate bonding on Zn sites and thus promoted CO production. This work could act as a promising way to reveal the mechanism of neighboring monomers and to influence catalysis.     

An extended model for describing pedestrian evacuation under the threat of artificial attack

An extended floor field model was proposed to investigate evacuation behaviors of pedestrians under the threat of artificial attack. In this model, pedestrian movement governed by the static and dynamic floor field, and the motion and assault of artificial attacker were involved simultaneously. Further, injuries with lower velocity and deaths of pedestrians caused by the attacker during evacuation were considered. And a new parameter $k_t$ was introduced. It is the sensitivity coefficient of attack threat floor field and could reflect quantitatively the extent of effect of attack threat on the decision-making of the individual. Moreover, effects of several key parameters such as the sensitivity coefficient, assault intensity and pedestrian density on evacuation dynamics were studied. Results show that pedestrian evacuation would display interesting phenomena transiting from rolling behavior to along-the-wall motion with aggravating extent of the impact of attackers on pedestrians, which refers $k_t$ in the model varying from 0.5 to 0.8. As assault intensity increases, more casualties would be caused and the available evacuation time would decrease, which means people have to flee the room in a shorter time period for survival. When the pedestrian density increases, more clogging at the exit would be generated and pedestrians would be more difficult to evacuate due to the limited capacity of egress and the reduction in the average speed of pedestrian flow caused by the injured. And the injured with limited motion capacity could hardly complete the evacuation owing to that they need more evacuation time and would retard the speed of the pedestrian flow.     

The study of ZnAl and ZnFe layered double hydroxide on the catalytic dechlorination and fire safety of polyvinyl chloride

Journal of Thermal Analysis and Calorimetry - The effect of OZnAl-LDH and OZnFe-LDH on the catalytic dechlorination, thermal decomposition and smoke suppression of polyvinyl chloride (PVC) during...     

Enhancing Clostridial Acetone-Butanol-Ethanol (ABE) Production and Improving Fuel Properties of ABE-enriched Biodiesel by Extractive Fermentation with Biodiesel

The extractive acetone–butanol–ethanol (ABE) fermentations of Clostridium acetobutylicum were evaluated using biodiesel as the in situ extractant. The biodiesel preferentially extracted butanol, minimized product inhibition, and increased production of butanol (from 11.6 to 16.5 gL⁻¹) and total solvents (from 20.0 to 29.9 gL⁻¹) by 42% and 50%, respectively. The fuel properties of the ABE-enriched biodiesel obtained from the extractive fermentations were analyzed. The key quality indicators of diesel fuel, such as the cetane number (increased from 48 to 54) and the cold filter plugging point (decreased from 5.8 to 0.2 °C), were significantly improved for the ABE-enriched biodiesel. Thus, the application of biodiesel as the extractant for ABE fermentation would increase ABE production, bypass the energy intensive butanol recovery process, and result in an ABE-enriched biodiesel with improved fuel properties.     

Synthesis of 2-aryl-4-(4-<Emphasis Type="Italic">β</Emphasis>-D-allopyranosyloxyphenyl)4,6,7,8-tetrahydroquinolin-5(1<Emphasis Type="Italic">H</Emphasis>)-one derivatives under solvent-free conditions and study of sedative activity

Under solvent-free conditions, syntheses of 2-aryl-4-(4-β-D-allopyranosyloxyphenyl)-4,6,7,8tetrahydroquinolin-5(1H)-one derivatives were carried out from chalcone (2a–2e), cyclohexane-1,3-dione (3), and NH₄OAc in excellent yield without using any catalysts. The structure of the new compounds were characterized by ¹H NMR, IR, and HR-MS spectroscopy. The preliminary bioassay tests of 4a–4j indicated that compounds 4b, 4e, and 4f exhibited potent sedative and hypnotic activity.