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61.
62.
We recently observed that the decanoylation of N-phenylthiocarbamoyl chitosan (2) with a mixture of decanoic anhydride and pyridine at 60 °C for 24 h afforded N,N-(decanoyl)phenythiocarbamoyl-/2-isothiocynato chitosan decanoate (3b) rather than the expected product N,N-(decanoyl)phenylthiocarbamoyl chitosan decanoate (3a). This result suggested that some of the N,N-(decanoyl)phenylthiocarmbamoyl groups had been converted to isothiocyanate groups during the decanoylation process. The subsequent reaction of compound 3b with aniline gave N,N-(decanoyl)phenylthiocarbamoyl/N-phenylthiocarbamoyl chitosan decanoate (4) in high yield. A solution of compound 4 in CHCl3 was then added to a solution of copper decanoate (5) in the same solvent, and the resulting mixture was cast onto a glass plate to give a cast film. The film was annealed at 200 °C in an oven to give a greenish film, which showed good near-infrared absorption characteristic in the range of 800–2200 nm.  相似文献   
63.
Enhancement of the dissolution rate of the poorly water-soluble hypoglycemic agent, gliclazide, by the aid of lyophilization was investigated. Mannitol, sodium lauryl sulfate (SLS) and polyvinyl pyrrolidone (PVP-k-30) were employed in different weight ratios (43%, 56% and 64% w/w, respectively) as water-soluble excipients in the formulation. Lyophilized systems were found to exhibit extremely higher in vitro dissolution rate compared to the unprocessed drug powder. Solid state characterization of the lyophilized systems using X-ray powder diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry techniques revealed that dissolution enhancement was attributable to transformation of gliclazide from the crystalline to an amorphous state in the solid dispersion formed during the lyophilization process. The gastrointestinal absorption and hypoglycemic effect of the lyophilized gliclazide/SLS system were investigated following oral administration to Albino rabbits. Cmax and area under the plasma concentration–time curve of gliclazide (AUC0–12) after administration of the lyophilized formulations were significantly higher than those obtained after administration of the unprocessed gliclazide.  相似文献   
64.
采用火焰原子吸收分光光度法对加硝酸和不加硝酸的浑浊和澄清水质样品中镍、锰、铜、锌、铅的浓度变化进行测定研究和对比,结果表明硝酸加入样品中能起到固定剂的作用,加入硝酸对于铜元素的浓度影响很小,对澄清水中的锰元素和铅元素影响也很小,但是加入硝酸对镍和锌元素有较大影响。  相似文献   
65.
H2S removal from an off‐gas stream was performed in a spray column by H2S reactive absorption into a NaOH solution. The individual and interactive effects of three independent operating variables on the percentage of absorbed H2S were investigated: the initial pH of the scrubbing solution, the initial scrubbing solution temperature, and the volumetric liquid‐to‐gas ratio. The optimum operating variables were determined by response surface methodology (RSM) attaining a percentage of absorbed H2S of 98.7 ± 0.2 %. Additionally, the process performance was modeled by an artificial neural network (ANN) to predict the percentage of absorbed H2S. The results showed that the experimental data agreed better with the ANN model than with the RSM results.  相似文献   
66.
基于溶液除湿热质传递过程中所遵循的质量平衡、能量平衡模型,以超声雾化溶液除湿系统(UADS)为例,探讨了在不同空气处理温度、湿度下,系统运行压力对除湿性能的影响。结果表明:随着运行压力的升高,UADS系统的除湿性能显著改善。特别是在所处理空气入口温度较高时,提升系统运行压力对除湿效率的提高作用更加显著。同时,当所处理空气的含湿量较大时,提高运行压力对系统除湿速率的增幅明显,而对除湿效率的改善作用减弱。此外,当除湿系统在较高压力下运行时,其除湿效率受所处理空气入口温湿度变化而产生的波动减小,系统性能稳定性显著改善。所得结果可对溶液除湿系统的高效、稳定运行提供积极参考。  相似文献   
67.
李子辉  蒋晶  金章勇  蔡泊志  曹永俊  李倩 《化工学报》2020,71(12):5842-5853
以聚己内酯(PCL)为基体,添加不同含量聚乳酸(PLA)熔融共混制备具有不同分散相形态的PCL/PLA共混物,利用超临界二氧化碳(scCO2)微孔发泡工艺制备不同发泡倍率和开孔率的PCL/PLA多孔材料用于吸油应用。针对边长3 mm正方体样品溶解度实验发现100 min后CO2在PCL中已达到饱和吸附状态。PLA分散相含量的增加显著增大了PCL/PLA共混物泡孔密度,并使共混泡孔尺寸减小且分布更加均匀;发泡温度升高6℃,泡孔尺寸增大50%,发泡倍率增大38%,开孔率减小了20%。PCL/PLA开孔材料具有明显的亲油疏水性,发泡倍率越高,疏水性越好;针对花生油和硅油的吸油实验发现材料吸油率与发泡倍率和开孔率整体呈正比,实际吸油量高于理论计算值,10次循环吸油测试后样品吸油率仅降低8.5%,材料吸油量与油品特性黏度关系不大。  相似文献   
68.
Developing efficient electrocatalysts for alkaline water electrolysis is central to substantial progress of alkaline hydrogen production. Herein, a Ni5P4 electrocatalyst incorporating single-atom Ru (Ni5P4-Ru) is synthesized through the filling of Ru3+ species into the metal vacancies of nickel hydroxides and subsequent phosphorization treatment. Electron paramagnetic resonance spectroscopy, X-ray-based measurements, and electron microscopy observations confirm the strong interaction between the nickel-vacancy defect and Ru cation, resulting in more than 3.83 wt% single-atom Ru incorporation in the obtained Ni5P4-Ru. The Ni5P4-Ru as an alkaline hydrogen evolution reaction catalyst achieves low onset potential of 17 mV and an overpotential of 54 mV at a current density of 10 mA cm-2 together with a small Tafel slope of 52.0 mV decade-1 and long-term stability. Further spectroscopy analyses combined with density functional theory calculations reveal that the doped Ru sites can cause localized structure polarization, which brings the low energy barrier for water dissociation on Ru site and the optimized hydrogen adsorption free energy on the interstitial site, well rationalizing the experimental reactivity.  相似文献   
69.
介绍我国分户楼板隔声及其隔声研究现状,详细阐述多层复合结构的减震隔声降噪地垫的结构、性能和安装,减震隔声降噪地垫与木地板配合使用,将其铺装于扫平层的140 mm厚现浇钢筋混凝土楼板之上,经江苏省建工建材检测中心检测,撞击声隔声为61 dB,能很好地满足住宅分户楼板撞击声隔声L'nT,W≤65 dB的要求。  相似文献   
70.
Si3N4 ceramics modified with SiC nanofibers were prepared by gel casting aiming to enhance the dielectric and microwave absorption properties at temperatures ranging from 25?°C to 800?°C within X-band (8.2–12.4?GHz). The results indicate that the complex permittivity and dielectric loss are significantly increased with increased weight fraction of SiC nanofibers in the Si3N4 ceramics. Meanwhile, both complex permittivity and dielectric loss of SiC nanofibers modified Si3N4 ceramics are obviously temperature-dependent, and increase with the higher test temperatures. Increased charges mobility along conducting paths made of self-interconnected SiC nanofibers together with multi-scale net-shaped structure composed of SiC nanofibers, Si3N4 grains and micro-pores are the main reason for these enhancements in dielectric properties. Moreover, the calculated microwave absorption demonstrates that much enhanced microwave attenuation abilities can be achieved in the SiC nanofibers modified Si3N4 ceramics, and temperature has positive effects on the microwave absorption performance. The SiC nanofibers modified Si3N4 ceramics will be promising candidates as microwave absorbing materials for high-temperature applications.  相似文献   
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