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All-at-once arrangement of both oxygen atoms of dioxygen into aliphatic C(sp^(3))–C(sp^(3))bonds for hydroxyketone difunctionalization

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Science China Chemistry 2021年第5期64卷 770-777页

作者： Xiaofeng Qiao yuhan lin Jiazhen Li Wanhong Ma Jincai Zhao Key Laboratory of Photochemistry CAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Bothβ-andγ-hydroxyketone structures are important units in biologically active molecules,synthetic drugs and fine *** there are some routes available for their manufacture from pre-functionalized groups on one or two matrix molecule(s),the approaches to simply and simultaneously deposit two oxygen atoms from dioxygen into two specific C(sp^(3))positions of pure saturated hydrocarbons have rarely succeeded because they are involved in the targeted activation of three inert C–Hσbonds all at ***,we show that a TiO_(2)-CH_(3)CN photocatalytic suspension system enables the insertion of dioxygen into one C(sp^(3))–C(sp^(3))bond of strained cycloparaffin derivatives,by which difunctionalized hydroxyketone products are obtained in a one-pot *** the cleavage event to release strain as the directional driving force,as-designed photocatalytic reaction systems show 21 examples ofβ-hydroxyketone products with 31%–76%isolated yields for three-membered ring derivatives and 5 examples ofγ-hydroxyketone products with 30%–63%isolated yields for four-membered ring substrates.^(18)O isotopic labeling experiments using^(18)O2,Ti^(18)O_(2) and intentionally added H218O,respectively,indicated that both oxygen atoms of hydroxyketone products were exclusively from dioxygen,suggesting a previously unknown H^(+)/TiO_(2)-e−catalyzed arrangement pathway of the hydroperoxide intermediate to convert dioxygen into hydroxyketone units.

关键词： TiO2 photocatalysis β-orγ-hydroxyketones strained cycloalkanes dioxygen activation

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Polysilsesquioxane‑PBO Wave‑Transparent Composite Paper with Excellent Mechanical Properties and Ultraviolet Aging Resistance

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Advanced Fiber Materials 2023年第6期5卷 2114-2126页

作者： yuhan lin Xiaoli Fan lin Tang Yusheng Tang Junwei Gu Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072ShaanxiPeople’s Republic of China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072ShaanxiPeople’s Republic of China Chongqing Key Laboratory of Green Synthesis and Applications College of ChemistryChongqing Normal UniversityChongqing 401331People’s Republic of China

The rapid development of radar antenna systems to meet requirements for high integration and precision places stringent requirements on the dielectric properties,mechanical properties and heat resistance of wave-transparent composite *** this paper,poly(p-phenylene-2,6-benzobisoxazole)(PBO)fibers are first dissolved by trifluoroacetic acid/methyl sulfonic acid to obtain PBO nanofibers(PNF),and the amino polysilsesquioxane(NH_(2)-POSS)is dispersed uniformly inside the PNF via ultrasonic-assisted and *** POSS-PNF composite paper is fabricated by the method of“suction filtration and hot-pressing”.Because of the uniformly dispersion of NH_(2)-POSS,the POSS-PNF composite paper has a low dielectric constant(ε,2.08)and dielectric loss tangent(tanδ,0.0047),and the wave-transparent coefficient(|T|2)is 96.7%(1 MHz),which is higher than that of PNF paper(95.5%,1 MHz).Additionally,the POSS-PNF composite paper possesses excellent tensile strength of 163.3 MPa,tensile modulus of 6.9 GPa,toughness of 9.1 MJ/m^(3),outstanding flame retardancy and excellent UV aging *** to a simulation of the radome honeycomb panel,POSS-PNF composite paper has low loss and reflections of electromagnetic waves in the X-band(8.4~12.4 GHz),and wide angle of incidence(0°-80°),which favor high|T|*** results indicate that the POSS-PNF composite paper has excellent potential for applications in the fields of aerospace,wearable flexible electronic devices and 5G communication.

关键词： PBO nanofibers POSS Wave-transparent Tensile strength

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Organic geochemical characteristics of bark coal in Changguang area: evidence from aromatic hydrocarbons

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International Journal of Coal Science & Technology 2020年第2期7卷 288-298页

作者： yuhan lin Shaoqing Wang Yuming Sha Kun Yang College of Geoscience and Surveying Engineering China University of Mining and TechnologyBeijingBeijing100083China

Seven coal samples were collected from Changguang area,a typical bark coal field in Zhejiang Province,*** organic geochemical characteristics and depositional environment of bark coal were studied by Rock–Eval pyrolysis,gas chromatography(GC),and gas chromatography–mass spectrometry(GC–MS)*** results show that all samples are type II *** values of total organic carbon(TOC),potential yield(S1+S2),and hydrogen index of these samples ranged from 65.80 wt%–87.00 wt%,170.43–232.89 mg HC/g,and 234–295 mg HC/g TOC,*** aromatic hydrocarbons compounds of bark coal samples,the phenanthrene series occupy the largest proportion(43.48%–53.74%),followed by the dibenzothiophens(7.33%–16.53%).The distributions of naphthalenes,diphenyls,and chrysene of the samples indicate the source inputs are mainly derived from terrestrial higher ***,the ratios of naphthalene and phenanthrene series compounds reveal the samples are in the mature *** biomarkers(Pr/Ph and C35/C31–35 homohopane),aromatic hydrocarbons(fluorene,dibenzofuran and dibenzothiophene),and high inertinite contents(14.7%–41.8%)suggest that bark coal was formed under relatively oxic conditions and was influenced by marine or brackish lakes environment.

关键词： Bark coal Aromatic hydrocarbon Organic geochemistry Maturity

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Characteristics of Hydrogen-rich Coals in Southern China:Implications from Organic Geochemistry and Carbon Isotopic Compositions

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Acta Geologica Sinica(English Edition) 2022年第1期96卷 309-320页

作者： lin yuhan WANG Shaoqing YANG Zongda ZHAO Yungang YANG Yi College of Geoscience and Surveying Engineering China University of Mining and Technology(Beijing)Beijing 100083China Wanbao Mining Ltd. Beijing 100053China

The organic geochemical characteristics of hydrogen-rich coal in southern China were investigated synthetically through organic geochemistry and carbon isotope *** results showed that the hydrogen contents of the test samples were more than 5.0% and the H/C atomic ratios were between *** were found to be composed mostly of Type Ⅱ-Ⅲ℃ kerogen,consistent with good hydrocarbon-generation *** R_(o)(0.54-1.10%)and T_(max)(430-453℃)values imply that the hydrogen-rich coals were in low maturity to mature *** carbon isotopic ratios(δ^(13)C_(org))of the samples used varied from −24.5‰ to −23.4‰,the barkinite content ranging from 13.9% to 83.3%,indicating a predominantly terrestrial origin with marine influence during coal *** organic geochemical parameters showed corresponding changes as the hydrogen content increased from 5.0% to 7.0%,however,the source inputs changed significantly when hydrogen content was greater than 6.0%.Terrestrial higher plants gradually become predominant within the coal-forming materials,whereas this dominant position is not apparent at lower hydrogen contents,which is attributable to the strong seawater effect during the hydrogen-rich coal formation process.

关键词： hydrogen-rich coal carbon isotope geochemistry Rock-Eval GC GC-MS

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Lithium extraction from salt lakes with different hydrochemical types in the Tibet Plateau

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Geoscience Frontiers 2023年第1期14卷 230-246页

作者： Tao Ding Mianping Zheng Suping Peng yuhan lin Xuefei Zhang Mingming Li College of Geoscience and Surveying Engineering China University of Mining and Technology(Beijing)Beijing 100083China MNR Key Laboratory of Saline Lake Resources and Environments Institute of Mineral ResourcesChinese Academy of Geological SciencesBeijing 100037China

The demand for lithium resources is increasing sharply with the rapid development of electric *** is of great economic significance to expand the geological resources of lithium and improve the utilization rate of lithium-containing salt *** this paper,the hydrochemical types of the lithium-containing salt lakes in the Tibet Plateau were classified according to a large amount of hydrochemical data obtained from a recent investigation on the Tibet *** addition,the lithium extraction methods used in the salt lakes within each hydrochemical type area were analyzed and summarized,which provided a reference for the selection of lithium extraction processes in the same hydrochemical type of lithium-containing salt lakes in the *** binding energies of Li(l)and anions in salt lakes with different hydrochemical types were calculated by density functional theory,which provides the theoretical basis for selecting the best lithium extraction technology in different salt *** emphasize that the process with the combined characteristics of high efficiency,economy and environmental protection should be selected according to the hydrochemical type of different salt *** the future,different salt lakes should focus on direct lithium extraction technology from the original brine.

关键词： Tibet Plateau Lithium-containing salt lake Hydrochemical type Lithium extraction process

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SiO_(2) nanofiber composite gel polymer electrolyte by in-situ polymerization for stable Li metal batteries

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Chinese Chemical Letters 2023年第3期34卷 536-540页

作者： Zhichuan Shen Jiawei Zhong Jiahong Chen Wenhao Xie Kun Yang yuhan lin Jinbiao Chen Zhicong Shi School of Materials and Energy Guangdong University of TechnologyGuangzhou 510006China

Gel polymer electrolytes(GPEs) are promising alternatives to liquid electrolytes applied in high-energydensity *** superior SiO_(2) nanofiber composite gel polymer electrolytes(SNCGPEs) are developed via in-situ ionic ring-opening polymerization of 1,3-dioxolane(DOL) monomers in SiO_(2) nanofiber membrane(PDOL-SiO_(2)) for lithium metal *** oxygen atoms of PDOL together with Si-O of SiO_(2) construct a more efficient channel for Li^(+) ***,the lithium ion transference number(t_(Li^(+)) and ionic conductivity(σ) at 30℃ of PDOL-SiO_(2) are 0.80 and 1.68×10^(-4)S/cm ***-SiO_(2) manifests the electrochemical decomposition potentials of 4.90 *** 0.5 mA/cm^(2),Li|PDOL-SiO_(2) |Li cell shows a steady cycling performance for nearly 1400 ***|PDOL-SiO_(2) |Li battery can steadily cycle at 0.5 C with a capacity retention rate of 89% after 200 *** cycling at 2 C,the capacity retention rate can maintain at 78% after 300 *** contribution provides a innovative strategy for accelerating Li^(+)transportation via designing PDOL molecular chains throughout the SiO_(2) nanofiber framework,which is crucial for high-energy-density LMBs.

关键词： SiO_(2)nanofiber In-situ polymerization Composite gel polymer electrolytes 1 3-Dioxolane Lithium metal-LFP battery

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Improved performance of CdSe/ZnS quantum dot light-emitting diodes through doping with small molecule CBP

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Optoelectronics Letters 2021年第11期17卷 656-660页

作者： lin yuhan HUANG Ye ZHU Qianpeng ZHANG Genggeng HU Junta National Engineering Lab of Special Display Technology' State Key Lab of Advanced Display TechnologyAcademy of Opto-Electronic Technology'Hefei University of TechnologyHefei 230009China School of Electronic Science and Applied Physics Hefei University of TechnologyHefei 230009China School of Instrument Science and Opto-electronics Engineering Hefei University of TechnologyHefei 230009China

The poor film formation of Cd Se/Zn S quantum dots(QDs) during spin-coating makes a substantial impact on the device performance of quantum dot light-emitting diodes(QLEDs). This work proposes a method to improve the morphology of the quantum dot light-emitting layer(EML) by adding small organic molecular 4,4'-Bis(9 H-carbazol-9-yl) biphenyl(CBP) into the layer. Its surface roughness reduces from 6.21 nm to 2.71 nm, which guarantees a good contact between hole transport layer(HTL) and EML. Consequently, the Cd Se/Zn S QDs:CBP based QLED achieves maximum external quantum efficiency(EQE) of 5.86%, and maximum brightness of 10 363 cd/m^(2). It is demonstrated that the additive of small organic molecules could be an effective way to improve the brightness and the efficiency of QLEDs.

关键词： QDs Improved performance of CdSe/ZnS quantum dot light-emitting diodes through doping with small molecule CBP ZnS

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High-strength super-hydrophobic double-layered PBO nanofiberpolytetrafluoroethylene nanocomposite paper for high-performance wave-transparent applications

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Science Bulletin 2022年第21期67卷 2196-2207页

作者： lin Tang Yusheng Tang Junliang Zhang yuhan lin Jie Kong Kun Zhou Junwei Gu Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore

Poly(p-phenylene-2,6-benzobisoxazole)nanofiber(PNF)paper is facing unprecedented challenges in enhancing the interaction between the PNFs and improving its *** this work,a sol–gel film transformation approach was developed to fabricate high-strength PNF *** ions formed coordination bonds between PNFs to obtain a preforming three-dimensional,interconnective nanofiber ***,polytetrafluoroethylene(PTFE)particles were sprayed onto the surface of the paper,followed by thermal treatment to obtain double-layered PTFE-P/PNF nanocomposite *** nanocomposite paper presents incredible tensile strength(271.6 MPa,increased by 52.9%),folding endurance,super-hydrophobicity,and self-cleaning ***,it exhibits low dielectric constant(2.06)and dielectric loss tangent(0.0133)*** to the wave-transparent model for a doublelayered dielectric established by Maxwell’s equations,the wave-transparent coefficients of electromagnetic waves incident from both sides of the paper are 97.6%(PNF side)and 96.0%(PTFE/P(S-co-BCB-coMMA)side),*** PTFE-P/PNF nanocomposite paper possesses great potential in the fields of wave-transparent applications.

关键词： Poly(p-phenylene-2,6-benzobisoxazole) Coordination bonds Tensile strength Wave-transparent Super-hydrophobicity

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对基于时空干涉的空间整形的畸变与光强校正

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激光与光电子学进展 2021年第3期58卷 203-211页

作者：林御寒石惠贾天卿华东师范大学精密光谱科学与技术国家重点实验室上海200241

时空干涉的飞秒激光空间整形技术是一种新型图形化激光加工方法,相比传统技术更加简单灵活并有更高的效率。然而此技术中的缩束系统造成的成像畸变严重影响了加工的准确性。本文模拟并分析了该系统中的畸变现象,利用空间光调制器的相位... 详细信息

时空干涉的飞秒激光空间整形技术是一种新型图形化激光加工方法,相比传统技术更加简单灵活并有更高的效率。然而此技术中的缩束系统造成的成像畸变严重影响了加工的准确性。本文模拟并分析了该系统中的畸变现象,利用空间光调制器的相位全息图补偿畸变引起的空间光场的位置变化和光强分布不均。此方法可使曝光处干涉图案的最大偏移量由10.66μm趋近于0,在实验中将相对最大偏差由60.42%降至8%以下,并使该处二维光强分布趋近于平顶光。该算法降低了时空干涉的飞秒激光空间整形技术对于缩束成像系统的设计需求,节省了成本与时间。基于以上方法,在不锈钢表面拼接加工出了1.5 mm×1.5 mm的具备多级别防伪能力的二维码图案。

关键词：激光器飞秒激光整形时空干涉畸变校正平顶光整形微纳加工

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晚二叠世树皮煤(体)的结构和反应性

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煤炭学报 2022年第4期47卷 1596-1607页

作者：王绍清林雨涵唐跃刚中国矿业大学(北京)地球科学与测绘工程学院北京100083

自从1933年谢家荣报道江西乐平地区典型树皮煤以来,树皮煤(体)因其具有特殊的化学性质,引起了广泛关注。典型的树皮煤和树皮体主要存在于中国南方晚二叠世,尽管在树皮煤(体)化学性质方面已经取得了一些重要的研究进展,但关于其结构特征... 详细信息

自从1933年谢家荣报道江西乐平地区典型树皮煤以来,树皮煤(体)因其具有特殊的化学性质,引起了广泛关注。典型的树皮煤和树皮体主要存在于中国南方晚二叠世,尽管在树皮煤(体)化学性质方面已经取得了一些重要的研究进展,但关于其结构特征和热反应性缺乏系统研究,直接影响了树皮煤的合理利用。通过结合已有的大量参考文献和课题组的研究数据,围绕树皮煤和树皮体的结构和热反应性方面,进行了细致的总结与分析,重点探讨了树皮煤(体)的化学组成、有机地球化学特征、化学结构特征和热反应性,重新分析了对树皮煤定义的界定,推测建立了树皮煤化学结构与植物前驱体化学结构之间的关系图,指出了树皮煤(体)的元素组成方面至少表现出4点特殊性质:高氢含量、高H/C原子比、高挥发分以及高硫含量。结构上主要讨论了树皮体的物理结构和化学结构2方面,表明了树皮体最明显的化学结构特征是具有丰富的脂肪族结构,在镜质组反射率从0.67%增加到1.12%,树皮体的形态结构逐渐由纤维状向不规则网状结构演化,其定向性排列越来越强,与镜质组的结构演化特征相似。树皮煤(体)具有许多异常的热行为,如强烈的热解作用、超高的基氏流动度、良好的生烃潜力和液化性能。最后对树皮煤的进一步利用途径提出了建议,也指明了树皮煤(体)下一步需要解决的问题。

关键词：树皮煤树皮体化学组成化学结构热反应有机地球化学

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