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A new triterpenoid saponin from the roots of Platycodon grandiflorum

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Chinese Chemical Letters 2007年第3期18卷 306-308页

作者： Wei Li Lan Xiang Jing Zhang yi nan zheng Li Kun HAN Masato Saito College of Chinese Material Medicine Jilin Agricultural University Changchun 130118 China School of Pharmacy Shangdong University Jinan 250012 China Beauty Care Laboratory Kanebo Home Products Ltd. YBP6F Kanagawa Japan

A new triterpenoid saponin, 3-O-β-D-glucopyranosyl 16-oxo-platycodigenin 28-O-β-D-apiofuranosyl-（1 → 3）-β-D-xylopyra- nosyl-（1→4）-α-L-rhamnopyranosyl-（1 → 2）-α-L-arabinopyra-nosyl ester, was isolated from the roots of Platycodon grandiflorum, together with three known saponins, including platycodin D, deapio platycoside E and platycoside E. The structure of the new compound, named 16-oxo-platycodin D, was elucidated on the basis of spectroscopic data.

关键词： Platycodon grandiflorum Triterpenoid saponin 16-oxo-Platycodin D

Fluorescent carbon dots synthesized in solid phase and air for application in LEDs

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nano Research 2024年第9期17卷 8495-8503页

作者： Wei-Jie zheng Zhao-nan Sun yi-Ming Wang Huan-Ming Xiong Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Fudan UniversityShanghai 200438China

Carbon dots(CDs)have been widely adopted as optical materials because of their excellent luminescent ***,most of the reported synthetic methods are conducted in solvents,especially hydrothermal/solvothermal reactions,leading to intractable problems such as toxic and flammable solvents,complex and inseparable by-products,and dangerously high pressures and ***-phase synthesis of CDs in air is an effective solution to overcome the above issues,but solid reactions always result in uncontrolled growth and agglomeration of *** this study,some inorganic salts are selected as catalysts for synthesizing CDs in solid states and air,which also play as dispersants to hinder CDs *** the meantime,some aromatic derivatives containing hydroxyl and amino groups are chosen as carbon sources,ground with the optimized catalyst,and then heated together in *** production yields are affected by the reaction time and reactant ratio,while the graphitization degrees of the CDs are determined by the reaction *** IG/ID value of their Raman spectra increases from 0.59 to 0.85,and the particle size decreases from 2.5 to 1.4 nm when the synthesis temperature is increased from 200 to 280℃.The as-prepared CDs show emission peaks ranging from 366 to 606 nm,with the photoluminescence(PL)quantum yield up to 53%.Their emission color variation mainly results from different carbon sources,which can be ascribed to the differences in the element composition,functional groups,and graphitic nitrogen content of these *** dispersing CDs of different concentrations into polyvinyl alcohol(PVA)and combining them with blue LEDs,cold,standard,and warm white light emitting devices(WLEDs)are prepared,with a color rendering index(CRI)up to *** the as-prepared CDs have antioxidant ability at high temperature,the as-prepared WLEDs have long lifespans,remaining the effective white luminescence after 72 h continuous work.

关键词： carbon dot solid-phase synthesis white LED photoluminescence inorganic salt catalysis

Enhanced quality of Al2O3/SiC gate stack via microwave plasma annealing

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Rare Metals 2024年第10期43卷 5362-5371页

作者： nan-nan You Xin-Yu Liu Qian Zhang Zhen Wang Jia-yi Wang Yang Xu Xiu-Yan Li Yu-zheng Guo Sheng-Kai Wang High-Frequency High-Voltage Device and Integrated Circuits R&D Center Institute of Microelectronics of the Chinese Academy of Sciences School of Integrated Circuits University of Chinese Academy of Sciences School of Electrical Engineering and Automation Wuhan University Department of Micro/nano Electronics School of Electronic Information and Electrical EngineeringShanghai Jiao Tong University

The high-quality gate dielectric on silicon carbide （SiC） surface is critical to fabricate high-performance SiC metal-oxide-semiconductor field-effect transistors（MOSFETs）.This research employs microwave plasma annealing （MPA） to obtain high-quality Al2O3/SiC gate *** designing MPA atmosphere and optimizing the plasma power,the SiC MOS capacitor with a Al2O3dielectric film shows the enhanced *** interface state density is reduced by 1 order of magnitude to 6×1011cm-2·eV-1,the breakdown electric field is increased,and the voltage shift is effectively suppressed Besides,the mechanism of MPA process is discussed in terms of the thermal effect and reactant species.X-ray photoelectron spectroscopy （XPS） results unveil oxygen plasma plays the main *** plasma power during the MPA process results in defect repairs of the firstneighbor Al-O bonding and partial removal of Al-O-H bond from the interface *** study demonstrates that MPA process is an effective option to realize highquality dielectric and interface on SiC.

关键词： Al2O3 Defect repairs Metal–oxide–semiconductor Microwave plasma annealing Silicon carbide X-ray photoelectron spectroscopy

Existence of long-range magnetic order in Heisenberg spin nanoribbons with edge modification

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Communications in Theoretical Physics 2024年第7期76卷 134-144页

作者： Da-cheng Ma Ling-yi Cui Chu-xiao Sun Xiao-dan Chi zheng-nan XianYu An Du College of Science Northeastern UniversityShenyang 110819China Department of Basic Science Dalian Naval AcademyDalian 116018China Department of Physics College of SciencesShenyang University of Chemical TechnologyShenyang 110142China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern UniversityChina Key Laboratory of Data Analytics and Optimization for Smart Industry(Northeastern University) Ministry of EducationChina

Long-range magnetic order appears on a side decorated Heisenberg spin nanoribbon at nonzero temperature,although no spontaneous magnetization exists in a one-or two-dimensional isotropic Heisenberg model at any nonzero temperature according to the Mermin-Wagner *** use of the spin Green's function method,we calculated the magnetizations of Heisenberg nanoribbons decorated by side spins with single-ion anisotropy and found that the system exhibits a nonzero transition temperature,whether the decorated edge spins of the system link together or separate from each *** the width of the nanoribbon achieves infinite limit,the transition temperatures of the system tend to the same finite constant eventually whether one edge or both edges are decorated by side spins in the *** results reveal that the magnetism of a low-dimensional spin system is different from that of a threedimensional spin *** the single-ion anisotropy of edge spins in a Heisenberg spin nanoribbon can be modulated by an electric field experimentally,various useful long-range magnetic orders of the system can be *** work can provide a detailed theoretical basis for designing and fabricating next-generation low-dimensional magnetic random-access memory.

关键词： nanoribbon magnetic anisotropy long-range magnetic order Heisenberg model transition temperature

The Logarithmic Sobolev Inequality for a Submanifold in Manifolds with Nonnegative Sectional Curvature

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Chinese Annals of Mathematics,Series B 2024年第3期45卷 487-496页

作者： Chengyang yi Yu zheng School of Mathematical Sciences East China Normal UniversityShanghai 200241China

The authors prove a sharp logarithmic Sobolev inequality which holds for compact submanifolds without boundary in Riemannian manifolds with nonnegative sectional curvature of arbitrary dimension and *** the Michael-Simon Sobolev inequality,this inequality includes a term involving the mean *** extends a recent result of Brendle with Euclidean setting.

关键词： Logarithmic Sobolev inequality Nonnegative sectional curvature Submanifold

Photocatalytic Minisci-type multicomponent reaction for the synthesis of 1-(halo)alkyl-3-heteroaryl bicyclo[1.1.1] pentanes

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Chinese Chemical Letters 2024年第10期35卷 6-8页

作者： Rong-nan yi Wei-Min He Key Laboratory of Food&Environment&Drug Monitoring and Testing of Universities in Hunan Province Hunan Police Academy.Changsha 410138China School of Chemistry and Chemical Engineering University of South ChinaHengyang 421001China

Bioisosteres play an important role in pharmaceutical and agricultural compound design that has been developed to enhance the properties of *** a sp3-rich small ring cage hydrocarbons,bicyclo[1.1.1]pentanes(BCPs)were commonly considered as a bioisostere of the para-substituted arenes,internal alkynes,and tert-butyl groups,and its introduction can significantly improve pharmacokinetic properties,including passive permeability,aqueous solubility,metabolic stability[1].Over the past decades,numerous pharmaceutically relevant molecules with biaryl frameworks were improved by the approach of bioisosteric *** strategies for the synthesis of such BCP-aryls derivatives mostly depend on the stepwise C-C formation via the direct addition to bridgehead C-C bond of[1.1.1]propellane to provide active BCP-intermediates and followed by a second transitionmetal cross-coupling ***,these pioneer works were limited by the low step economy,the use of unstable reagents,and harsh conditions in industrial productions.

关键词： synthesis substituted alkyl

Investigating the Effects of V2C MXene on Improving the Switching Stability and Reducing the Operation Voltages of TiO2-Based Memristors

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Chinese Journal of Electronics 2024年第5期33卷 1181-1187页

作者： nan HE Lei WANG yi TONG College of Electronic and Optical Engineering College of Flexible Electronics (Future Technology) and College of Integrated Circuit Science and Engineering Nanjing University of Posts and Telecommunications Gusu Laboratory of Materials

Three-atoms-type V2C MXene, an emerging class of transition metal carbides, has attracted tremendous attention in the fabrication of advanced memristive devices due to its excellent electrochemical properties. However,the inserted effects and corresponding physical mechanisms of inserting V2C on traditional TiO2-based memristors have not been clearly explored. In this work, exhaustive electrical characterizations of the V2C/TiO2-based devices exhibit enhanced performance（e.g., improved switching stability and lower operating voltages） compared to the TiO2-based counterparts. In addition, the advantaged influences of the inserted V2C have also been studied by means of first-principles calculations, confirming that V2C MXene enables controllable internal ionic process and facilitated formation mechanism of the Ag conductive filaments. This work demonstrates a way to combine experimental and theoretical investigations to reveal the positive effects of introducing V2C MXene on memristor, which is beneficial for fabricating performance-enhanced memristors.

关键词： Performance evaluation Fabrication Memristors Process control Metals Switches Stability analysis Memristor V2C MXene First-principles calculation Switching stability Formation mechanism

Ultrasound-driven self-decomposition porphyrins as metal-free CO precursors for gas and sonodynamic synergistic therapy

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Science China Chemistry 2024年第5期67卷 1624-1635页

作者： Shuxin Liu Jinjuan Ma Xiang Xu Aiguo Wang nan zheng School of Chemical Engineering Dalian University of TechnologyDalian 116024China Department of Comparative Medicine Laboratory Animal Center Dalian Medical UniversityDalian 116000China Cancer Hospital of Dalian University of Technology Shenyang 116000China

Carbon monoxide(CO) is an endogenous therapeutic gas with an anti-tumor effect. The precise delivery and controlled release of CO in tumor tissues play crucial roles in anti-cancer treatment. However, efficient in situ generation of CO from metal-free COreleasing molecules(CORMs) remains a formidable challenge. Herein, we develop ultrasound(US)-driven self-decomposition porphyrin as organic and metal-free US-CORMs, which can spatiotemporally control the CO release(347 mmol CO/mol porphyrin) efficiently under physiologically harmless US conditions(1.0 MHz, 1.5 W/cm^(2), 50% duty cycle, 50 min). Moreover,porphyrin as a sonosensitizer can also generate reactive oxygen species(ROS) under US treatment to achieve sonodynamic therapy(SDT). Advanced functions of such porphyrin-based CORMs in CO gas-sonodynamic synergistic treatment have been demonstrated by evaluating the in vitro and in vivo anti-tumor effects.

关键词： porphyrin sonodynamic therapy metal-free CO precursors ultrasound-driven gas therapy

Photoinduced bismuth vanadate-catalyzed C(sp^(2))-H functionalization

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Chinese Chemical Letters 2024年第3期35卷 1-2页

作者： Rong-nan yi Wei-Min He Key Laboratory of Food&Environment&Drug Monitoring and Testing of Universities in Hunan Province Hunan Police AcademyChangsha 410138China School of Chemistry and Chemical Engineering University of South ChinaHengyang 421001China

Visible light-induced organic reactions have gained much attention in recent years due to their mild conditions and high efficiency[1,2].In this context,many efficient photocatalysts including transition metal complex... 详细信息

关键词： bismuth catalyzed gained