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Efficient continuous synthesis of 2-hydroxycarbazole and 4-hydroxycarbazole in a millimeter scale photoreactor

Chinese Chemical Letters 2024年第4期35卷 399-403页

作者： Zhixiang Li zhirong yang Chang Yao Bin Wu Gang Qian Xuezhi Duan Xinggui Zhou Jing Zhang State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China

2-Hydroxycarbazole and 4-hydroxycarbazole are important chemicals with extensive applications in optoelectronic materials and pharmaceutical field.State of the art yield of 2-hydroxycarbazole is~30%and the reaction time is typically in hours or days.Herein,we developed a green route for the continuous and high-throughput synthesis of 2-hydroxycarbazole and 4-hydroxycarbazole via photochemical intramolecular cyclization of 3–hydroxy-2–chloro-diphenylamine using a self-designed millimeter scale photoreactor,which was designed based on sizing-up and numbering-up strategies for a decent liquid holdup(6.8 m L)and fabricated via femtosecond laser engraving technique.The photochemical synthesis was carried out continuously under the illumination of 365 nm UV-LED with dimethyl sulfoxide as solvent and potassium t-butoxide as catalyst.It was found that under optimized conditions a 2-hydroxycarbazole yield of 31.6%and a 4-hydroxycarbazole yield of 11.1%were obtained with a residence time of 1 min.Compared to semibatch operations,the reaction time was shortened by 1–2 orders of magnitude.As a result,a throughput of 11.3 g/day 2-hydroxycarbazole and 4.0 g/day 4-hydroxycarbazole can be achieved from the photoreactor.It was proposed that the short reaction time and high product yield are resulted from higher photon transfer rates and more uniform photon distribution provided by the millimeter scale photoreactor,which enhances the reaction rates and mitigates overreaction.

关键词： Millimeter scale reactor 2-Hydroxycarbazole Photochemistry UV-LED Process intensification

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Poisoning effect of polyvinyl chloride on the catalytic pyrolysis of mixed plastics over zeolites

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Science China Chemistry 2024年第7期67卷 2265-2273页

作者： Jiangchun Yuan Wenjie Wang Weixiao Sun zhirong yang Yueqiang Cao Wenyao Chen Xiaohu Ge Gang Qian Xiang Feng Xuezhi Duan Xinggui Zhou Kevin M.Van Geem Jing Zhang State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China Laboratory for Chemical Technology(LCT) Department of MaterialsTextiles and Chemical EngineeringFaculty of Engineering&ArchitectureGhent UniversityZwijnaarde B-9052Belgium State Key Lab of Heavy Oil Processing China University of PetroleumQingdao 266580China

Nowadays,the chemical recycling is applied for only 1%of total waste plastics,largely due to contaminants in plastic waste and difficulty in product control.As the major contaminant,polyvinyl chloride(PVC)often forms corrosive hydrogen chloride(HCl)during the chemical recycling,which may cause severe catalyst deactivation and equipment damage.However,the investigation on catalytic pyrolysis(the major route for plastics chemical recycling)of the PVC containing mixed plastics has been rarely reported.Here,catalytic co-pyrolysis of PVC and polyethylene(PE)was studied over an aromatization catalyst,Pt/ZSM-5,since the basic building block aromatics are desired products from plastics chemical recycling.The poisoning effect of PVC vapor on the catalyst stability was explored by collective efforts of thorough product analysis and catalyst characterization.It was found that the HCl evolving from PVC has an autocatalytic effect that promotes the scission of dehydrochlorinated PVC,resulting in the high yield of benzene and acetylene from PVC.On the other hand,the presence of PVC suppressed the aromatics formation from PE,largely due to the poisoning effect of PVC-derived HCl on the Pt/ZSM-5.The deactivation is irreversible as evidenced by the decreased zeolite crystallinity and the loss of strong acid sites that are key to the aromatization,possibly due to the removal of framework Al upon the interaction with HCl.The modification with octadecylphosphonic acid only slightly alleviated the PVC poisoning effect.The insights on the PVC poisoning of zeolite catalysts provided in this work may guide the process design of chemical recycling of PVC containing waste plastics.

关键词： polyvinyl chloride polyethylene zeolite aromatics deactivation

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Comparative effectiveness of different hepatocellular carcinoma screening intervals or modalities:a systematic review and meta-analysis

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Chinese Medical Journal 2023年第11期136卷 1322-1330页

作者： Jichun yang zhirong yang Xueyang Zeng Shuqing Yu Le Gao Yu Jiang Feng Sun Department of Epidemiology and Biostatistics School of Public HealthPeking UniversityBeijing 100191China Department of Epidemiology and Biostatistics School of Population Medicine and Public HealthChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100730China Primary Care Unit School of Clinical MedicineUniversity of CambridgeCambridgeshire CB18RNUK Shenzhen Institutes of Advanced Technology Chinese Academy of SciencesShenzhenGuangdong 518055China Centre for Safe Medication Practice and Research Department of Pharmacology and PharmacyLi Ka Shing Faculty of MedicineUniversity of Hong KongHong Kong 999077China

Background:Current guidelines recommend hepatocellular carcinoma(HCC)screening in high-risk populations.However,the ideal HCC screening interval and screening modality have not been determined.This study aimed to compare the screening efficacy among different modalities with various intervals.Methods:PubMed and other nine databases were searched through June 30,2021.Binary outcomes were pooled using risk ratio(RR)with 95%confidence intervals(CIs).Survival rates were also pooled using RR with 95%CIs because most eligible studies only provided the number of survival patients instead of hazard ratio.Results:In all,13 studies were included.Two random controlled trials(RCTs)and six cohort studies compared screening intervals for ultrasonography(US)screening and found no significant differences between shorter(3-or 4-month)and longer(6-or 12-month)screening intervals in terms of early HCC proportion,HCC significant mortality,1-year survival rate;screening at 6-month interval significantly increased the proportion of early HCC(RR=1.17,95%confidence interval[CI]:1.08-1.26)and prolonged the 5-year survival rate(RR=1.39,95%CI:1.07-1.82)relative to the 12-month interval results.Three other RCTs and two cohort studies compared different screening modalities in cirrhosis or chronic hepatitis B,which indicated no statistical differences in the proportion of early HCC(RR=0.89,95%CI:0.40-1.96)and HCC mortality(RR=0.69,95%CI:0.23-2.09)between the biannual US and annual computed tomography(CT screening).Biannual US screening showed a lower proportion of early HCC than biannual magnetic resonance imaging(MRI)(RR=0.60,95%CI:0.37-0.97)and biannual US combined with annual CT(RR=1.31,95%CI:1.13-1.51)screening.The proportion of early HCC in the contrast-enhanced US group was slightly higher than that in the B-mode US(RR=1.08,95%CI:1.00-1.23)group.Conclusions:The evidence suggests that 6 months may be the best HCC screening interval for US screening.The effectiveness of CT and MRI is better than US during same screening intervals.However

关键词： Hepatocellular carcinoma Screening interval Screening modality Effectiveness Systematic review Meta-analysis

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Characteristics and Containment of 74 Imported COVID-19 Outbreaks: Experiences, Lessons, and Implications — China, 2020–2021

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China CDC weekly 2022年第50期4卷 1131-1135,I0010-I0015页

作者： Fuxiao Li Chang Wei Bingli Li Tengfei Lin Yiwen Jiang Di Liu zhirong yang Zuyao yang Feng Sha Jinling Tang Shenzhen Institutes of Advanced Technology Chinese Academy of SciencesShenzhen CityGuangdong ProvinceChina Division of Epidemiology JC School of Public Health and Primary Carethe Chinese University of Hong KongHong Kong Special Administrate RegionChina Department of Clinical Data Center Guangzhou Womenand Children's Medical CenterGuangzhou Medical UniversityGuangzhou CityGuangdong ProvinceChina.

What is already known about this topic?After the initial coronavirus disease 2019(COVID-19)outbreak in Wuhan,China,the outbreaks during the dynamic-zero policy period in the mainland of China have not been systematically documented.What is added by this report?We summarized the characteristics of 74 imported COVID-19 outbreaks between March 19,2020 and December 31,2021.All outbreaks of early severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)variants were successfully contained with the aid of nucleic acid testing,modern communication technologies,and non-pharmacological interventions.What are the implications for public health practice?These findings provide us with confidence for the containment of future emerging infectious diseases alike at early stages to prevent pandemics or to win time to gain experience,develop vaccines and drugs,vaccinate people,and wait for the possible lessening of the virus’pathogenicity.

关键词： drugs mainland summarized

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Hospital Strain and COVID-19 Fatality—England,April 2020–March 2022

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China CDC weekly 2022年第52期4卷 1176-1180,I0001-I0005页

作者： Tengfei Lin Ziyi Zhao zhirong yang Bingli Li Chang Wei Fuxiao Li Yiwen Jiang Di Liu Zuyao yang Feng Sha Jinling Tang Shenzhen Institutes of Advanced Technology Chinese Academy of SciencesShenzhen CityGuangdong ProvinceChina Division of Epidemiology JC School of Public Health and Primary Carethe Chinese University of Hong KongHong Kong Special Administrate RegionChina Department of Clinical Data Center Guangzhou Women and Children's Medical CenterGuangzhou Medical UniversityGuangzhou CityGuangdong ProvinceChina.

Summary What is already known about this topic?During the coronavirus disease 2019(COVID-19)pandemic,tremendous efforts have been made in countries to suppress epidemic peaks and strengthen hospital services to avoid hospital strain and ultimately reduce the risk of death from COVID-19.However,there is limited empirical evidence that hospital strain increases COVID-19 deaths.

关键词： death COV services

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Residence time distribution and heat/mass transfer performance of a millimeter scale butterfly-shaped reactor

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Chinese Chemical Letters 2023年第4期34卷 332-337页

作者： Haicheng Lv Jundi Wang Zhongming Shu Gang Qian Xuezhi Duan zhirong yang Xinggui Zhou Jing Zhang State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China

A millimeter scale butterfly-shaped reactor was proposed based on sizing-up strategy and fabricated via femtosecond laser engraving. An improvement of mixing performance and residence time distribution was realized by means of contraction and expansion of the reaction channel. The liquid holdup was greatly increased through connection of multiple mixing units. Structure optimization of the reactor was carried out by computational fluid dynamics simulation, from which the effect of reactor internals on mixing and the influence of parallel branching structure on heat transfer were discussed. The UV–vis absorption spectroscopy was used to determine the residence time distribution in the reactor, and characteristic parameters such as skewness and dimensionless variance were obtained. Further, a chained stagnant flow model was proposed to precisely describe the trailing phenomenon caused by fluid stagnation and laminar flow in small scale reactors, which enables a better fit for the experimental results of the asymmetric residence time distribution. In addition, the heat transfer performance of the reactor was investigated, and the overall heat transfer coefficient was 110–600 W m^(-2)K-1in the flow rate range of 10–40 m L/min.

关键词： Millimeter scale reactor Computational fluid dynamics Residence time distribution Chained stagnant flow model Overall heat transfer coefficient

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Mechanistic insights into the active intermediates of 2,6-diaminopyridine dinitration

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Chinese Journal of Chemical Engineering 2023年第4期56卷 160-168页

作者： Junao Zhu zhirong yang Yuanhan Chen Mingming Chen Zhen Liu Yueqiang Cao Jing Zhang Gang Qian Xinggui Zhou Xuezhi Duan State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China

Mechanistic understanding of the active intermediates of 2,6-diaminopyridine(DAP) dinitration in the concentrated nitric-sulfuric acid system is of crucial importance for the selectivity control of target product, i.e., 2,6-diamino-3,5-dinitropyridine(DADNP). The active intermediates determining the product selectivity are theoretically studied. The HSO_(4)^(-)-NO_(2)^(+) complex is proposed as the dominant active nitrating intermediate for the first time, which shows low energy barrier(i.e., 10.19 kcal·mol^(-1),1 kcal = 4.186 k J) for direct dinitration of DAP to DADNP. The formed water during the reaction results in not only the formation of less active SO_(4)^(2-)-NO_(2)^(+) complex, but also the occurance of DAP sulfonation(DAP-SO_(3)H intermediate)to facilitate the formation of mononitration byproduct. Meanwhile, the accompanied thermal effects cause the generation of undesirable pyridine-NHNO_(2) intermediate, which is difficult to be rearranged to yield DADNP, inhibiting the reaction and thus giving low DAP conversion. The insights reported here elucidates the importance of thermal effects elimination and water content control, confirmed experimentally in the batch-and micro-reaction systems.

关键词： 2,6-Diaminopyridine Nitration mechanism Active intermediates Thermal effects Negative water effects

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Effect of edge cracks on critical current degradation in REBCO tapes under tensile stress

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Superconductivity 2022年第1期1卷 52-62页

作者： zhirong yang Yi Li Peng Song Mingzhi Guan Feng Feng Timing Qu State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Department of Mechanical Engineering Advanced Manufacturing InstituteTexas Center for SuperconductivityUniversity of HoustonHoustonTX 77024USA Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China Lab of Intelligent Manufacturing and Precision Machining Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China

The slitting process for manufacturing REBa2Cu3O7δ(REBCO,RE=Rare earth)tapes of required width significantly improves the production efficiency and reduces production costs.However,edge cracks induced by the slitting process of wide REBCO tapes may cause premature degradation under high tensile stress in highfield magnets.Therefore,it is necessary to evaluate the effect of edge cracks of REBCO tapes on the critical current(Ic)degradation.Firstly,Ic degradation under artificial cracks was measured to validate the applicability of linear elastic fracture mechanics for the REBCO layer.The maximum circumferential stress criterion was used to derive the mixed-mode stress intensity factor of multiple oblique edge cracks.A semi-analytical model considering edge crack properties such as angleβ,spacing d,and length a,was built to evaluate the critical load and critical crack.We found that when the stress intensity factor at the crack tip is below KIC?2:3 MPa ffiffiffiffim p,edge cracks did not propagate.We examined commercial REBCO tapes manufactured by two different processes,concluding that edge cracks in these tapes will not cause premature degradation.

关键词： REBCO Degradation Stress intensity factor Multiple oblique edge cracks Fracture toughness

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中国东北地区火烧迹地木生真菌多样性和区系组成

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菌物学报 2024年第3期43卷 217-228页

作者：武英达杨知融员瑗北京林业大学生态与自然保护学院林木资源高效生产全国重点实验室北京100083 中国消防救援学院森林草原火灾风险防控应急管理部重点实验室北京102202 北京林业大学林学院北京100083

分解和火干扰是森林凋落物养分循环的重要生态过程,木生真菌作为分解者在营养物质循环、土壤形成和全球碳平衡中发挥着不可替代的重要作用,火烧迹地这种特殊的生态环境又为木生真菌提供了独特的生长环境。本研究比较分析了我国东北地区... 详细信息

分解和火干扰是森林凋落物养分循环的重要生态过程,木生真菌作为分解者在营养物质循环、土壤形成和全球碳平衡中发挥着不可替代的重要作用,火烧迹地这种特殊的生态环境又为木生真菌提供了独特的生长环境。本研究比较分析了我国东北地区的3个火烧迹地木生真菌物种多样性、分布特征和生态习性。调查发现3个火烧迹地木生真菌共15目68科154属248种,其中大兴安岭火烧迹地103种、小兴安岭126种、长白山148种,优势科均为多孔菌科和锈革孔菌科。3个火烧迹地的共有属和共有种分别为34个和33个。在寄主偏好性、区系地理成分方面,3个火烧迹地木生真菌均表现出相似比例和特征,具有明显的寒温带区系特征。物种出现频次方面,3个火烧迹地木生真菌的常见种、偶见种和稀有种虽然数量不同,但其比例相似,其中大兴安岭火烧迹地和小兴安岭火烧迹地的常见种、偶见种和稀有种组成的比例更相近。通过比较分析3个不同过火时间和气候特征的火烧迹地木生真菌物种多样性、寄主偏好性和区系地理成分,发现火干扰和不同恢复时期对木生真菌物种多样性具有一定影响,而植被类型和气候是影响木生真菌区系组成的主要因素。

关键词：木生真菌物种多样性真菌区系生态习性

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基于公园城市场景营造下的有轨电车站点环境评估与优化策略

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城市轨道交通研究 2024年第7期27卷 280-284页

作者：杨智荣王玮上海大学上海美术学院上海200444 西南交通大学设计艺术学院 610031成都

[目的]在当今新时代公园城市生态建设与新型城镇化的发展背景之下,探索城市新场景营造与城市轨道交通环境相结合的规划方向与影响因素。[方法]基于成都公园城市的场景营造建设实践,以“环境性”“文化性”和“社会性”作为“场景营造”... 详细信息

[目的]在当今新时代公园城市生态建设与新型城镇化的发展背景之下,探索城市新场景营造与城市轨道交通环境相结合的规划方向与影响因素。[方法]基于成都公园城市的场景营造建设实践,以“环境性”“文化性”和“社会性”作为“场景营造”的评价标准,构建了由3项一级评价指标、10项二级评价指标组成的有轨电车站点环境评价标准与指标体系,并综合分析成都有轨电车蓉2号线西南交大站点环境的优劣情况。[结果及结论]在公园城市场景营造原则和有轨电车站点环境评价体系的指导下,对成都有轨电车蓉2号线西南交大站环境现状进行调研分析;针对站点环境建筑形式单一、场景意象模糊等环境问题,提出有轨电车站点便捷可达性、功能性、舒适性等方面的优化建议,以实现以人为本、绿色交通、产城一体的“公园城市+轨道交通”的新场景营造。

关键词：有轨电车公园城市场景优化评价体系

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