模块化微反应系统内溴化间甲基苯甲醚连续合成

根据微化工技术发展的主要趋势，针对4-溴-3-甲基苯甲醚间歇非均相合成技术存在的问题，以微筛孔反应器与玻璃微珠填充床为核心功能微设备单元构建了模块化微反应系统，并在此模块化微反应系统内对液-液非均相连续溴化合成4-溴-3-甲基苯甲醚开展研究。通过优化操作条件，在溴浓度(x_{\mathrm{B}{\mathrm{r}}_{\mathrm{2}}})为17.5%（质量分数）、溴与间甲基苯甲醚摩尔比(n_{\mathrm{B}{\mathrm{r}}_{\mathrm{2}}}/n_M)为1.01、反应起始温度(T)为 0℃、停留时间为0.78 min条件下，4-溴-3-甲基苯甲醚的收率大于98%，多溴代副产物的含量仅为1%。与传统间歇溴化反应相比，模块化微反应系统内连续溴化反应具有十分明显的优势：可将间歇过程连续化，在保证安全的基础上极大地提升了反应的效率（时空收率为6.5×10⁴ kg/(m³·h)）；另外，该过程是由传质控制的，微反应器的传质性能优异，可极大地改善产品的选择性（多溴代副产物的量减少50%）。该研究为4-溴-3-甲基苯甲醚的连续高效安全合成提供了技术和设备依据。     

Preparation and flocculation properties of biodegradable konjac glucomannan-grafted poly(trimethyl allyl ammonium chloride)

Polymer Bulletin - Preparation of konjac glucomannan-grafted poly(trimethyl allyl ammonium chloride) (KGM-g-PTMAAC) was carried out using KGM as polysaccharide matrix and TMAAC as cationic...     

Fractional order battery modelling methodologies for electric vehicle applications: Recent advances and perspectives

Science China Technological Sciences - Accurate modelling of lithium ion batteries is crucial for battery management in electric vehicles. Recent studies have revealed the fractional order nature...     

森林抚育对森林生态系统的影响

伴随着我国社会经济的稳固发展,人们的生活质量逐渐有了明显改善,而在生态问题趋于严重使人们的环境保护意识显著提高的过程中,森林抚育对于森林生态系统的作用和价值愈发凸显。对此,文章针对森林抚育,从提高森林利用率、维持森林动植物生态平衡、增加可利用水资源等多个方面就其对森林生态系统的影响进行了分析,旨在给予相关森林保护工作者可行的帮助,并以此促进我国森林开发工作的可持续发展。     

Effect of garbage collection in iterative algorithms on Spark: an experimental analysis

The Journal of Supercomputing - Spark is one of the most widely used systems for the distributed processing of big data. Its performance bottlenecks are mainly due to the network I/O, disk I/O, and...     

A Cloud-Based Wireless Radio Intensity Recording System

Wireless Personal Communications - In recent years, many wireless communication services have become indispensable for our daily life, such as voice telephoning and the internet surfing. However,...     

Novel Bi-Doped Amorphous SnOx Nanoshells for Efficient Electrochemical CO2 Reduction into Formate at Low Overpotentials

Engineering novel Sn-based bimetallic materials could provide intriguing catalytic properties to boost the electrochemical CO₂ reduction. Herein, the first synthesis of homogeneous Sn_1−xBi_x alloy nanoparticles (x up to 0.20) with native Bi-doped amorphous SnO_x shells for efficient CO₂ reduction is reported. The Bi-SnO_x nanoshells boost the production of formate with high Faradaic efficiencies (>90%) over a wide potential window (−0.67 to −0.92 V vs RHE) with low overpotentials, outperforming current tin oxide catalysts. The state-of-the-art Bi-SnO_x nanoshells derived from Sn_0.80Bi_0.20 alloy nanoparticles exhibit a great partial current density of 74.6 mA cm⁻² and high Faradaic efficiency of 95.8%. The detailed electrocatalytic analyses and corresponding density functional theory calculations simultaneously reveal that the incorporation of Bi atoms into Sn species facilitates formate production by suppressing the formation of H₂ and CO.     

Expanded coprime array for DOA estimation: augmented consecutive co-array and reduced mutual coupling

Multidimensional Systems and Signal Processing - Generalized coprime structure decomposes the interleaved subarrays in the conventional coprime array by introducing a displacement and the resulting...