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Strategies for constructing seven-membered rings:Applications in natural product synthesis

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Chinese Chemical Letters 2024年第6期35卷 53-70页

作者： Peng chen Lijuan Liang yufei Zhu Zhimin Xing Zhenhua Jia Teck-Peng Loh College of Advanced Interdisciplinary Science and Technology Henan University of TechnologyZhengzhou 450001China Division of Chemistry and Biological Chemistry School of Chemistry Chemical Engineeringand BiotechnologyNanyang Technological UniversitySingapore 637371Singapore Institute of Advanced Synthesis School of Chemistry and Molecular Engineering Nanjing Tech UniversityNanjing 211816China State Key Laboratory of Applied Organic Chemistry Department of ChemistryLanzhou UniversityLanzhou 730000China

The seven-membered ring motifs are found in bioactive pharmaceuticals and a wide range of natural products,including alkaloids and terpenoids,which hold significant importance in synthetic chemistry and has garnered considerable attention from both academia and *** the challenges faced in the past decade,the total synthesis of natural products incorporating the non-aromatic cycloheptane skeletons remains a compelling ***,numerous elegant strategies for constructing the sevenmembered ring system have been successfully *** review focuses on the recent advancements in this field from 2017 to April 2023,highlighting key transformations utilized to construct the non-aromatic cycloheptane core structures and serves as a valuable guide for synthetic chemists engaged in the total synthesis of natural products containing seven-membered ring motifs.

关键词： Seven-membered rings Total synthesis Natural products Synthetic strategy Cycloheptane

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多组合虚拟电厂中氢储能低碳经济配置与优化

电网与清洁能源 2024年第3期40卷 107-118页

作者：陈永权方瑜华北电力大学经济与管理学院北京102206

提出蓄电池-氢混合储能虚拟电厂优化运行方案,首先分析各运行单元的特性并建立协同运行优化模型,然后在虚拟电厂应用蓄电池的基础上,增加由电解槽、储氢罐和燃料电池组成的氢能系统,以实现蓄电池与氢能系统混合储能。考虑电价型需求响... 详细信息

提出蓄电池-氢混合储能虚拟电厂优化运行方案,首先分析各运行单元的特性并建立协同运行优化模型,然后在虚拟电厂应用蓄电池的基础上,增加由电解槽、储氢罐和燃料电池组成的氢能系统,以实现蓄电池与氢能系统混合储能。考虑电价型需求响应和阶梯型碳交易理论,较分析5种不同方案的虚拟电厂的优化运行成本及收益,实例证明蓄电池-氢混合储能的风光虚拟电厂方案具有更好的经济性和低碳性。

关键词：虚拟电厂蓄电池-氢混合储能经济评价

Stretchable,Transparent,and Ultra-Broadband Terahertz Shielding Thin Films Based on Wrinkled MXene Architectures

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Nano-Micro Letters 2024年第9期16卷 110-122页

作者： Shaodian Yang Zhiqiang Lin Ximiao Wang Junhua Huang Rongliang Yang Zibo chen Yi Jia Zhiping Zeng Zhaolong Cao Hongjia Zhu Yougen Hu Enen Li Huanjun chen Tianwu Wang Shaozhi Deng Xuchun Gui State Key Laboratory of Optoelectronic Materials and Technologies School of Electronics and Information TechnologySun Yat-Sen UniversityGuangzhou 510275People’s Republic of China National Key Laboratory of Materials for Integrated Circuits Shenzhen Institute of Advanced Electronic MaterialsShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055People’s Republic of China Guangdong Province Key Laboratory of Display Material and Technology Guangzhou 510275People’s Republic of China China Academy of Aerospace Science and Innovation Beijing 100176People’s Republic of China School of Materials Science and Engineering Sun Yat-Sen UniversityGuangzhou 510275People’s Republic of China GBA Branch of Aerospace Information Research Institute Chinese Academy of SciencesGuangzhou 510700People’s Republic of China School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing 100049People’s Republic of China Guangdong Provincial Key Laboratory of Terahertz Quantum Electromagnetics Guangzhou 510700People’s Republic of China

With the increasing demand for terahertz(THz)technology in security inspection,medical imaging,and flexible electronics,there is a significant need for stretchable and transparent THz electromagnetic interference(EMI)shielding *** EMI shielding materials,like opaque metals and carbon-based films,face challenges in achieving both high transparency and high shielding efficiency(SE).Here,a wrinkled structure strategy was proposed to construct ultra-thin,stretchable,and transparent terahertz shielding MXene films,which possesses both isotropous wrinkles(height about 50 nm)and periodic wrinkles(height about 500 nm).Compared to flat film,the wrinkled MXene film(8 nm)demonstrates a remarkable 36.5%increase in SE within the THz *** wrinkled MXene film exhibits an EMI SE of 21.1 dB at the thickness of 100 nm,and an average EMI SE/t of 700 dBμm^(−1)over the 0.1-10 *** calculations suggest that the wrinkled structure enhances the film’s conductivity and surface plasmon resonances,resulting in an improved THz wave ***,the wrinkled structure enhances the MXene films’stretchability and *** bending and stretching(at 30%strain)cycles,the average THz transmittance of the wrinkled film is only 0.5%and 2.4%,*** outstanding performances of the wrinkled MXene film make it a promising THz electromagnetic shielding materials for future smart windows and wearable electronics.

关键词： Terahertz Wrinkle structure Electromagnetic interference shielding MXene

台湾地区中坚企业的发展经验及对内地培育专精特新企业的启示

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台湾研究 2024年第2期 66-76页

作者：程宇陈晓芳福建省习近平新时代中国特色社会主义思想研究中心福建理工大学互联网经贸学院

作为近几十年来少有的成功实现从低收入到高收入跨越发展的经济体,台湾地区的中小企业在其中扮演了“蚂蚁雄兵”的重要角色,台湾地区也因此被国际上誉为“中小企业的王国”。在新结构经济学视野下,台湾地区中坚企业的成功经验离不开基... 详细信息

作为近几十年来少有的成功实现从低收入到高收入跨越发展的经济体,台湾地区的中小企业在其中扮演了“蚂蚁雄兵”的重要角色,台湾地区也因此被国际上誉为“中小企业的王国”。在新结构经济学视野下,台湾地区中坚企业的成功经验离不开基于要素赋、比较优势和企业自生能力的发展路径,如对一定范围市场的专注;企业研发能力较强,具有自生能力;全球视野开阔,参与全球价值链分工和创新创业制度文化等。当前,培育专精特新企业是祖国内地工业强基战略的重要支撑,专精特新“小巨人”企业和专精特新冠军企业正在逐步成长并形成梯度成长路径,台湾地区中坚企业发展经验对内地培育专精特新企业具有重要启示意义。

关键词：中坚企业专精特新企业要素禀赋

New insights into the effect of hard carbons microstructure on the diffusion of sodium ions into closed pores

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Chinese Chemical Letters 2024年第6期35卷 155-160页

作者： Mingxin Song Lijing Xie Fangyuan Su Zonglin Yi Quangui Guo cheng-Meng chen CAS Key Laboratory of Carbon Materials Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China University of Chinese Academy of Sciences Beijing 100049China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Closed pores formed in hard carbons play an essential role in sodium storage at plateau ***,the effect of different structural features on the diffusion of sodium ions into closed pores remains ***,a precursor reconstruction strategy is conducted to regulate carbon microstructures including interlayer spacing,defect concentration,and closed pore volume by changing the ratio of aromatic and polysaccharide *** structure parts tend to develop disordered carbons with fewer defects,larger interlayer spacing,and smaller closed pore volume,while polysaccharide components prefer to form disordered carbons with more defects,smaller interlayer spacing,and larger closed pore *** the correlation analysis of microstructure features and the sodium storage capacity below 0.1 *** finds that the intercalation capacity is proportional to the ratio of pseudo-graphitic domains,whereas the pore filling capacity appeared at lower potential gradually decreases with the increasing defect concentration due to homo-ionic repulsion effect,without linear correlation with shortrange microcrystalline and closed pore *** optimized sample with suitable interlayer spacing and defect concentration exhibits a high plateau capacity of 241.7 m Ah/*** work provides insights into the exploitation of closed pore sodium storage performance.

关键词： Precursor reconstruction Hard carbons Structural features Closed pore filling Sodium-ion batteries

Construction of daily precipitation series and the observational characteristics of extreme precipitation in Tianjin,China during 1888-2022

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Advances in Climate Change Research 2024年第1期15卷 52-61页

作者： Peng SI Qing-Xiang LI Xiao-Yang chen Min WANG Chuan-Jun LUO Tianjin Meteorological Information Center Tianjin Meteorological BureauTianjin 300074China Research Centerfor Ecology and Environment of Central Asia Chinese Academy of SciencesWulumuqi 830011China School of Atmospheric Sciences Sun Yat-sen UniversityZhuhai 528478China Key Laboratory of Tropical Amosphere-Ocean System Ministry of EducationZhuhai 528478China Shaoguan Meteorological Service Shaoguan 512028China

Given the difficulties in rescuing and ensuring the quality of long-term climate data,current studies on century-scale climate change are usually limited to annual and monthly data,resulting in the poor detection of extreme climate events and their changes before *** this study,we reconstructed a daily precipitation series for Tianjin from 15 September 1887 to 31 December 2022 on the basis of the most comprehensive daily precipitation records collected from the Tianjin Meteorological Archive,China,and in reference to the precipitation analysis results based on the datasets developed by the Climatic Research Unit Time-Series version 4.06,Global Precipitation Climatology Centre and University of Delaware along with the application of various homogenisation methods for climate *** approach provides a complete and reliable century-long daily precipitation series for the study of regional or local extreme weather and climate *** reconstructed daily dataset reveals that the annual precipitation amount and R95 intensity in Tianjin during 1888-2022 lack significant trends and have values of 0.74±6.99 and-1.84±3.22 mm per decade,*** the annual and seasonal scales,the precipitation amount and R95 intensity,particularly those in autumn,have increased since the latter half of the 20th century relative to those in ***,the increase in precipitation amount and R95 intensity is relatively limited compared with that in atmospheric water vapour content due to surface warming,indicating the highly sensitive response of extreme precipitation events to *** addition,the estimates for the return periods of 5,10,20,50 and 100 years covering 1888-2022,1888-1950 and 1951-2022 depict that the intensity of heavy rain and above magnitude was highest in 1888-1950 and decreased in 1951-2022.

关键词： Over a century-long timescale Daily precipitation series Extreme precipitation Return period

PNEC和GABA在肺神经内分泌肿瘤中的作用

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解放军医学杂志 2024年第3期49卷 288-296页

作者：赵小琼陈文孙玉洁蔺晨雨岳渊李蕊张涛肖漓佳木斯大学基础医学院黑龙江佳木斯154007 解放军总医院第八医学中心呼吸与危重症医学部研究所/北京市器官移植与免疫调节重点实验室北京100091 河北北方学院研究生学院河北张家口075000

目的探讨肺神经内分泌细胞(PNEC)和γ-氨基丁酸(GABA)在肺神经内分泌肿瘤(PNET)患者中的作用。方法收集2018年10月-2022年1月解放军总医院第八医学中心呼吸与危重症医学部胸外科收治的29例PNET患者的病理标本,采用HE染色观察形态学特征... 详细信息

目的探讨肺神经内分泌细胞(PNEC)和γ-氨基丁酸(GABA)在肺神经内分泌肿瘤(PNET)患者中的作用。方法收集2018年10月-2022年1月解放军总医院第八医学中心呼吸与危重症医学部胸外科收治的29例PNET患者的病理标本,采用HE染色观察形态学特征,免疫组织化学染色观察突触素(Syn)、嗜铬粒蛋白A(CgA)、CD56、Ki-67、CD86和CD163的表达水平,双抗体免疫荧光共染检测不同类型PNET中降钙素基因相关肽(CGRP)和谷氨酸脱羧酶(GAD)65/67的表达情况,并分析GAD65/67阳性PNEC与巨噬细胞极化的相关性。结果HE染色结果显示,4种类型的PNET组织均具有神经内分泌特征——玫瑰花样结构和器官嵌套或栅栏状图案,但各有差异;有丝分裂细胞占比由低到高为典型类癌(TC)、不典型类癌(AC)、大细胞神经内分泌癌(LCNEC)、小细胞肺癌(SCLC)。免疫组织化学染色结果显示,类癌(TC和AC)的Syn、CgA阳性表达率及Syn、CgA、CD56阳性程度均明显高于LCNEC和SCLC(P75%。类癌的PNEC数量明显高于LCNEC、SCLC和瘤旁组织(P0.05)。免疫荧光染色结果显示,95%的PNEC共表达GAD65/67;类癌GAD65/67阳性细胞数明显增多于LCNEC、SCLC和瘤旁组织(P0.05)。免疫组织化学染色结果还显示,瘤旁组织中CD86阳性M1巨噬细胞明显多于CD163阳性M2巨噬细胞(P<0.05);而在AC、LCNEC和SCLC中,M2巨噬细胞均明显多于M1巨噬细胞(P<0.01)。相关性分析显示,PNET中GAD65/67阳性PNEC细胞数与肿瘤间质中CD163阳性M2巨噬细胞数呈负相关(r=-0.6336,P=0.0174)。结论PNEC是肺组织中GABA的主要来源,在肺中发挥免疫调节作用,可能参与PNET的进展。

关键词：肺神经内分泌细胞 γ-氨基丁酸巨噬细胞肺神经内分泌肿瘤

A metal-free coordination–insertion ring-opening polymerization of tetrahydrofuran by the central metalloid bis(pentafluorophenyl)(phenoxy)borane

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Chinese Chemical Letters 2024年第3期35卷 419-422页

作者： cheng Wu Yixuan Liu Chunsheng Xiao chenyang Hu Xuan Pang Xuesi chen Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

A new strategy for the metal-free coordination–insertion ring-opening polymerization of tetrahydrofuran by the central metalloid Boron has been first ***(pentafluorophenyl)(phenoxy)borane was used as a catalyst for the polymerization reaction *** polytetrahydrofuran with high molecular weight and narrow molecular weight distribution could be *** proposed mechanism was studied by MALDI-TOF,ESI-MS and O-18 isotope labeling analyses as a metal-free coordination insertion mechanism.

关键词： Metal-free catalyst Bis(pentafluorophenyl)(phenoxy)borane Coordination–insertion mechanism Ring-opening polymerization Polytetrahydrofuran

Nitrogen–sulfur co-doped porous carbon derived from asphalt as efficient catalyst for oxygen reduction

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Rare Metals 2024年第1期43卷 380-388页

作者： Jing-Sheng Ma Ming-Zai Wu Ling chen Li-Xing Zhang Ying Xiong Key Laboratory of Structure and Functional Regulation of Hybrid Materials Ministry of EducationInstitute of EnergyHefei Comprehensive National Science CenterAnhui UniversityHefei 230601China

As an environment-friendly and low-cost petrochemical by-product, asphalt has great potential in the preparation of metal-free oxygen reduction electrocatalysts with excellent performance and outstanding stability. In this paper, we converted asphalt into porous carbon nanosheets by a simple activation method, using potassium citrate as the swelling agent.

关键词： stability porous catalyst