“联用技术及元素形态”国际课程探索与实践*

充分利用线上教学的优势,对化学院本科生开设了“联用技术及元素形态”国际课程,避免了传统教学中组织、协调外籍/外地专家资源过程中必要的各种消耗,极大程度地整合教学资源、改善教学效果。在该课程的探索与实践过程中,学生们对痕量元素形态及基于等离子体质谱的各种联用技术产生了极大的兴趣,激发了他们的主动学习热情;教师之间及师生之间的沟通趋向更简单、更灵活、更实时,为后续线上线下混合式国际课程建设提供了良好的基础和借鉴。     

甲烷-二氧化碳重整制合成气与现代分析技术应用于探究性化工专业实验的设计与探索

以甲烷-二氧化碳重整制合成气为实例，设计探究性实验，将合成气的制备和现代分析技术应用于化工专业实验的教学实践中以提高学生的创新和实践能力。实验包括催化剂的制备，催化剂的性能评价和催化剂的表征等3大部分。采用工业最常用的浸渍法制备含有不同助剂的Ni/X/γ-Al2O3（X为Co，Fe，MgO，CeO2）催化剂，以甲烷-二氧化碳重整反应评价其催化性能，并采用XRD、H2-TPR、BET和TG对催化剂的微观结构进行表征。结合催化剂的性能评价结果和表征结果，探讨不同助剂对镍基催化剂性能的改善效果及机制。通过开设该实验，可以让学生了解化工学科的前沿知识以及现代分析技术的基本原理和用途，掌握专业的实验操作、数据处理和谱图绘制方法，提高学生的专业素养和综合能力。     

Binary neutron stars gravitational wave detection based on wavelet packet analysis and convolutional neural networks

This work investigates the detection of binary neutron stars gravitational wave based on convolutional neural network(CNN).To promote the detection performance and efficiency,we proposed a scheme based on wavelet packet(WP)decomposition and CNN.The WP decomposition is a time-frequency method and can enhance the discriminant features between gravitational wave signal and noise before detection.The CNN conducts the gravitational wave detection by learning a function mapping relation from the data under being processed to the space of detection results.This function-mapping-relation style detection scheme can detection efficiency significantly.In this work,instrument effects are con-sidered,and the noise are computed from a power spectral density(PSD)equivalent to the Advanced LIGO design sensitivity.The quantitative evaluations and comparisons with the state-of-art method matched filtering show the excellent performances for BNS gravitational wave detection.On efficiency,the current experiments show that this WP-CNN-based scheme is more than 960 times faster than the matched filtering.     

Determination of cobalt ion based on polyethyleneimine modified silver nanoclustersEI北大核心CSCD

PolyethyleneiminePEImodified silver nanoclustersAg NCswere synthesized through chemical reduction method by using PEI as stabilizerAgNO3 as silve source and ascorbic acid as reducing agentand it was applied to the detection of cobalt ions. It was found that the fluorescence of the silver nanoclusters was quenched by Co2+ for the aggregation of PEI-Ag NCs caused by the coordination between cobalt ion and amino group on polyethyleneimine. Under the optimized experimental conditionsthe fluorescence quenching degree of PEI-Ag NCs was piecewise linear with the concentration of cobalt ion in the range of 8.30×10-7-4.17×10-4 mol/L and the detection limit was 0.41 μµmol/L. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

Some optimizations on detecting gravitational wave using convolutional neural network

This work investigates the problem of detecting gravitational wave (GW) events based on simulated damped sinusoid signals contaminated with white Gaussian noise. It is treated as a classification problem with one class for the interesting events. The proposed scheme consists of the following two successive steps: decomposing the data using a wavelet packet, representing the GW signal and noise using the derived decomposition coefficients; and determining the existence of any GW event using a convolutional neural network (CNN) with a logistic regression output layer. The characteristic of this work is its comprehensive investigations on CNN structure, detection window width, data resolution, wavelet packet decomposition and detection window overlap scheme. Extensive simulation experiments show excellent performances for reliable detection of signals with a range of GW model parameters and signal-to-noise ratios. While we use a simple waveform model in this study, we expect the method to be particularly valuable when the potential GW shapes are too complex to be characterized with a template bank.     

A Three‐Minute Synthesis and Purification of Ibuprofen: Pushing the Limits of Continuous‐Flow Processing

In a total residence time of three minutes, ibuprofen was assembled from its elementary building blocks with an average yield of above 90 % for each step. A scale‐up of this five‐stage process (3 bond‐forming steps, one work‐up, and one in‐line liquid–liquid separation) provided ibuprofen at a rate of 8.09 g h^?1 (equivalent to 70.8 kg y^?1) using a system with an overall footprint of half the size of a standard laboratory fume hood. Aside from the high throughput, several other aspects of this synthesis expand the capabilities of continuous‐flow processing, including a Friedel–Crafts acylation run under neat conditions and promoted by AlCl₃, an exothermic in‐line quench of high concentrations of precipitation‐prone AlCl₃, liquid–liquid separations run at or above 200 psi to provide solvent‐free product, and the use of highly aggressive oxidants, such as iodine monochloride. The use of simple, inexpensive, and readily available reagents thus affords a practical synthesis of this important generic pharmaceutical.     

Review of the role and methodology of high resolution approaches in aroma analysis

Analysis of the odour complexity in food and beverage products demands high resolution approaches for distinguishing individual aroma-impact compound(s), and for assessing their contribution to the global aroma of a sample. This paper aims to review current applications incorporating different advanced separation methodologies, and their roles in achieving high resolution aroma analysis. This includes prior low resolution gas chromatography–olfactometry (GC–O) with fractionation procedures using chemical manipulation, adsorption chromatography and ion exchange separation. Innovative multidimensional gas chromatography (MDGC) arrangements that are appropriately designed with olfactometry are of specific focus here. The revelation of resolved components using these integrated approaches provides significantly improved knowledge of aroma composition in samples.     

洗涤用品质量安全检测技术研究进展

洗涤用品是日常使用的产品,其质量安全受到广大消费者的关注。洗涤用品中可能存在的化学风险物质,将对消费者的健康安全产生负面影响。为了减少和避免洗涤用品质量安全问题,研究人员采用多种分析测试技术,开发、建立了洗涤用品中化学风险物质的检测方法。该文综述了近年来洗涤用品质量安全检测技术的研究进展,以期为相关领域的科技人员提供理论支持和技术参考。     

Trends in biosensing platforms for SARS-CoV-2 detection: A critical appraisal against standard detection tools

In this ongoing theme of coronavirus disease 2019 (COVID-19) pandemic, highly sensitive analytical testing platforms are extremely necessary to detect SARS-CoV-2 RNA and antiviral antibodies. To limit the viral spread, prompt and precise diagnosis is crucial to facilitate treatment and ensure effective isolation. Accurate detection of antibodies (IgG and IgM) is imperative to understand the prevalence of SARS-CoV-2 in public and to inspect the proportion of immune individuals. In this review, we demonstrate and evaluate some tests that have been used commonly to detect SARS-CoV-2. These include nucleic acid and serological tests for the detection of SARS-CoV-2 RNA and specific antibodies in infected people. Moreover, the vitality of biosensing technologies emphasizing on optical and electrochemical biosensors toward the detection of SARS-CoV-2 has also been discussed here. The early diagnosis of COVID-19 based on detection of reactive oxygen species overproduction because of virus-induced dysfunctioning of lung cells has also been highlighted.