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Highly dispersive tetrahedral vanadium species on pure silica ZSM-12 zeolite boosting the selective oxidation of cyclohexane into cyclohexanone

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Science China Chemistry 2024年第7期67卷 2206-2214页

作者： menglin Xie Ting li Chao Wu Xiaoling liu Jinling Ni Siqin Yao Yu Zhou Shibo Xi Jun Wang State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China Institute of Sustainability for Chemicals Energy and Environment(ISCE2)Agency for ScienceTechnology and Research(A*STAR)Singapore 627833Republic of Singapore College of Materials Science and Engineering Sichuan UniversityChengdu 610065China

The selective oxidation of cyclohexane is a promising green route for the production of KA oil(cyclohexanol and cyclohexanone),but remains a huge challenge to design high-performing heterogeneous catalysts under mild conditions.Herein,a pure silica ZSM-12(MTW topology)zeolite was applied as the support to immobilize highly dispersive tetrahedrally coordinated vanadium(V)species and the constructed catalyst 1%V/SZ-12 exhibited high efficiency in the fast and selective oxidation of cyclohexane into cyclohexanone with H2O2.The reaction completed within 30 s,affording the selectivity of 99%towards cyclohexanone and the extremely high turnover frequency(TOF)of 5,891 h^(-1).1%V/SZ-12 was facilely reused with stable activity and feasibly extended to the oxidation of various cyclohexane derivatives.The one-dimensional 12-membered ring microchannels contributed to the formation and accessibility of tetrahedrally coordinated high valent V5+species as the robust active centers,which activated H2O2to generate V–O–O·,the active oxygen species for the electrophilic attack on cyclohexane to produce cyclohexanone as the sole product.

关键词： zeolite metal doping cyclohexane oxidation heterogeneous catalysis

Phonon Thermal Transport at Interfaces of a Graphene/Vertically Aligned Carbon Nanotubes/Hexagonal Boron Nitride Sandwiched Heterostructure

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Chinese Physics Letters 2024年第1期41卷 57-62页

作者：李檬璘 Muhammad Asif Shakoori 王瑞鹏李海鹏 School of Materials Science and Physics China University of Mining and TechnologyXuzhou 221116China

Molecular dynamics simulation is used to calculate the interfacial thermal resistance of a graphene/carbon nanotubes/hexagonal boron nitride(Gr/CNTs/hBN)sandwiched heterostructure,in which vertically aligned carbon nanotube(VACNT)arrays are covalently bonded to graphene and hexagonal boron nitride layers.We find that the interfacial thermal resistance(ITR)of the Gr/VACNT/hBN sandwiched heterostructure is one to two orders of magnitude smaller than the ITR of a Gr/hBN van der Waals heterostructure with the same plane size.It is observed that covalent bonding effectively enhances the phonon coupling between Gr and hBN layers,resulting in an increase in the overlap factor of phonon density of states between Gr and hBN,thus reducing the ITR of Gr and hBN.In addition,the chirality,size(diameter and length),and packing density of sandwich-layer VACNTs have an important influence on the ITR of the heterostructure.Under the same CNT diameter and length,the ITR of the sandwiched heterostructure with armchair-shaped VACNTs is higher than that of the sandwiched heterostructure with zigzag-shaped VACNTs due to the different chemical bonding of chiral CNTs with Gr and hBN.When the armchair-shaped CNT diameter increases or the length decreases,the ITR of the sandwiched heterostructure tends to decrease.Moreover,the increase in the VACNT packing density also leads to a continuous decrease in the ITR of the sandwiched heterostructure,attributed to the extremely high intrinsic thermal conductivity of CNTs and the increase of out-of-plane heat transfer channels.This work may be helpful for understanding the mechanism for ITR in multilayer vertical heterostructures,and provides theoretical guidance for a new strategy to regulate the interlayer thermal resistance of heterostructures by optimizing the design of sandwich layer thermal interface materials.

关键词： sandwich shaped packing

Hypoglycemic activities of flowers of Xanthoceras sorbifolia and identification of anti-oxidant components by off-line UPLC-QTOF-MS/MS-free radical scavenging detection

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Chinese Herbal Medicines 2024年第1期16卷 151-161页

作者： Xiajing Xu Yongli Guo menglin Chen Ning li Yi Sun Shumeng Ren Jiao Xiao Dongmei Wang Xiaoqiu liu Yingni Pan School of Chinese Materia Medica Key Laboratory for TCM Material Basis Study and Innovative Drug Development of Shenyang CityShenyang Pharmaceutical UniversityShenyang 110016China Institute of Chinese Materia Medica China Academy of Chinese Medical SciencesBeijing 100700China School of Pharmacy Shenyang Pharmaceutical UniversityShenyang 110016China

Objective: To identify phytochemical constituents present in the extract of flowers of Xanthoceras sorbifolia and evaluate their anti-oxidant and anti-hyperglycemic capacities.Methods: The AlCl3colorimetric method and Prussian Blue assay were used to determine the contents of total flavonoids and total phenolic acids in extraction layers, and the bioactive layers was screened through anti-oxidative activity in vitro. The Waters ACQUITY UPLC system and a Waters ACQUITY UPLC BEH C18column(2.0 mm × 150 mm, 5 μm) were used to identify the ingredients. And anti-oxidative ingredients were screened by off-line UPLC-QTOF-MS/MS-free radical scavenging. The ameliorative role of it was further evaluated in a high-fat, streptozotocin-induced type 2 diabetic rat model and the study was carried out on NADPH oxidase(PDB ID: 2CDU) by molecular docking.Results: Combined with the results of activity screening in vitro, the anti-oxidative part was identified as the ethyl acetate layer. A total of 24 chemical constituents were identified by liquid chromatographymass spectrometry in the ethyl acetate layer and 13 main anti-oxidative active constituents were preliminarily screened out through off-line UPLC-QTOF-MS/MS-free radical scavenging. In vivo experiments showed that flowers of X. sorbifolia could significantly reduce the blood glucose level of diabetic mice and alleviate liver cell damage. Based on the results of docking analysis related to the identified phytocompounds and oxidase which involved in type 2 diabetes, quercetin 3-O-rutinoside, kaempferol-3-O-rhamnoside, isorhamnetin-3-O-glucoside, and isoquercitrin showed a better inhibitory profile.Conclusion: The ethyl acetate layer was rich in flavonoids and phenolic acids and had significant anti-oxidant activity, which could prevent hyperglycemia. This observed activity profile suggested X. sorbifolia flowers as a promising new source of tea to develop alternative natural anti-diabetic products with a high safety margin.

关键词： anti-hyperglycemic activity anti-oxidant flowers of Xanthoceras sorbifolia Bunge NADPH oxidase off-line UPLC-QTOF-MS/MS-free radical scavenging

Encapsulated carbon nanotube array as a thermal interface material compatible with standard electronics packaging

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Nano Research 2023年第8期16卷 11389-11400页

作者： Ruixiang Bai Yangbing Wei Jiyuan Xu Xiaobo li menglin li Ziwen Zou Xinyan Huang Chengyu liu Yiwei Sun Menglong Hao Key Laboratory of Energy Thermal conversion and control of Ministry of Education National Engineering Research Center of Power Generation Control and SafetySchool of Energy and EnvironmentSoutheast UniversityNanjing 210096China School of Materials Science and Engineering School of Energy and EnvironmentSoutheast UniversityNanjing 210096China Nanjing Research Institute of Electronics Technology Nanjing 210039China Research Centre for Fire Engineering Hong Kong Polytechnic UniversityKowloon 999077Hong KongChina State Key Laboratory of Bioelectronics School of Instrument Science and EngineeringSoutheast UniversityNanjing 210096China

Vertically aligned carbon nanotubes arrays(VACNTs)are a promising candidate for the thermal interface material(TIM)of next-generation electronic devices due to their attractive thermal and mechanical properties.However,the environment required for synthesizing VACNTs is harsh and severely incompatible with standard device packaging processes.VACNTs’extremely low in-plane thermal conductivity also limits its performance for cooling hot spots.Here,using a transfer-and-encapsulate strategy,a two-step soldering method is developed to cap both ends of the VACNTs with copper microfoils,forming a standalone Cu-VACNTs-Cu sandwich TIM and avoiding the need to directly grow VACNTs on chip die.This new TIM is fully compatible with standard packaging,with excellent flexibility and high thermal conductivities in both in-plane and through-plane directions.The mechanical compliance behavior and mechanism,which are critical for TIM applications,are investigated in depth using in situ nanoindentation.The thermal performance is further verified in an actual light emitting diode(LED)cooling experiment,demonstrating low thermal resistance,good reliability,and achieving a 17℃ temperature reduction compared with state-of-the-art commercial TIMs.This study provides a viable solution to VACNTs’longstanding problem in device integration and free-end contact resistance,bringing it much closer to application and solving the critical thermal bottleneck in next-generation electronics.

关键词： vertically aligned carbon nanotube arrays(VACNTs) sandwich structure thermal conductivity thermal interface materials(TIMs)

Chemically bonded multi-nanolayer inorganic aerogel with a record-low thermal conductivity in a vacuum

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National Science Review 2023年第10期10卷 96-105页

作者： Hongxuan Yu menglin li Yuanpeng Deng Shubin Fu Jingran Guo Han Zhao Jianing Zhang Shixuan Dang Pengyu Zhang Jian Zhou Dizhou liu Duola Wang Chuanwei Zhang Menglong Hao Xiang Xu Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology and Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast University Key Lab of Aerospace Bearing Technology and Equipment of the Ministry of Industry and Information Technology Harbin Institute of Technology

Inorganic aerogels have exhibited many superior characteristics with extensive applications,but are still plagued by a nearly century-old tradeoff between their mechanical and thermal properties.When reducing thermal conductivity by ultralow density,inorganic aerogels generally suffer from large fragility due to their brittle nature or weak joint crosslinking,while enhancing the mechanical robustness by material design and structural engineering,they easily sacrifice thermal insulation and stability.Here,we report a chemically bonded multi-nanolayer design and synthesis of a graphene/amorphous boron nitride aerogel to address this typical tradeoff to further enhance mechanical and thermal properties.Attributed to the chemically bonded interface and coupled toughening effect,our aerogels display a low density of 0.8 mg cm-3with ultrahigh flexibility(elastic compressive strain up to 99% and bending strain up to 90%),and exceptional thermostability(strength degradation lid materials to date.This unique combination of mechanical and thermal properties offers an attractive material system for thermal superinsulation at extreme conditions.

关键词： inorganic aerogels multi-nanolayer mechanical-thermal tradeoff flexibility thermal superinsulation

对外投资政策、逆向技术溢出与技术依赖对创新绩效的影响效应

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经济问题探索 2024年第5期 149-167页

作者：黄梦琳李富有西安交通大学经济与金融学院西安710061

对外投资是经济全球化背景下重要战略,创新绩效是企业持续发展的主要动力,对外投资产生逆向技术溢出提升企业创新绩效,对外投资同时伴随技术依赖不利于企业创新长期发展。对外投资政策是直接调节对外投资,间接影响逆向技术溢出与技术依... 详细信息

对外投资是经济全球化背景下重要战略,创新绩效是企业持续发展的主要动力,对外投资产生逆向技术溢出提升企业创新绩效,对外投资同时伴随技术依赖不利于企业创新长期发展。对外投资政策是直接调节对外投资,间接影响逆向技术溢出与技术依赖对创新绩效作用的关键因素。本文以对外投资为门槛分析其对创新绩效的分效应,采用PSTR模型估计得知,随着对外投资水平提高,中区制、高区制地区逆向技术溢出、技术依赖对创新绩效影响显著但方向相反。采用面板固定效应模型分析总效应,逆向技术溢出与技术依赖的交互作用抑制企业创新绩效的提高,同时对外投资政策力度发挥抑制效应,政策连续性、政策稳定性发挥激励效应。从高技术行业与其他行业、不同企业性质和企业规模角度进行异质性分析,通过投资方式、创新意愿、创新能力、创新动机、创新合作对创新绩效进行机制检验,并提出改善对外投资政策及提升创新绩效的有关建议。

关键词：政策力度政策连续性政策稳定性逆向技术溢出技术依赖创新绩效

Effects of Three Commonly-used Diuretics on the Urinary Proteome

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Genomics, Proteomics & Bioinformatics 2014年第3期12卷 120-126页

作者： Xundou li Mindi Zhao menglin li Lulu Jia Youhe Gao National Key Laboratory of Medical Molecular Biology Department of Physiology and Pathophysiology Institute of Basic Medical Sciences Chinese Academy of Medical Sciences Peking Union Medical College

Biomarker is the measurable change associated with a physiological or pathophysiological process. Unlike blood which has mechanisms to keep the internal environment homeostatic, urine is more likely to reflect changes of the body. As a result, urine is likely to be a better biomarker source than blood. However, since the urinary proteome is affected by many factors, including diuretics, careful evaluation of those effects is necessary if urinary proteomics is used for biomarker discovery. Here, we evaluated the effects of three commonly-used diuretics （furosemide, F; hydrochlorothiazide, H; and spirolactone, S） on the urinary proteome in rats. Urine samples were collected before and after intragastric administration of diuretics at therapeutic doses and the proteomes were analyzed using label-free liquid chromatography-tandem mass spectrometry （LC-MS/MS）. Based on the criteria of P ≤ 0.05, a fold change ≥2, a spectral count ≥ 5, and false positive rate （FDR） ≤1%, 14 proteins （seven for F, five for H, and two for S） were identified by Progenesis LC-MS. The human orthologs of most of these 14 proteins are stable in the healthy human urinary proteome, and ten of them are reported as disease biomarkers. Thus, our results suggest that the effects of diuretics deserve more attention in future urinary protein biomarker studies. Moreover, the distinct effects of diuretics on the urinary proteome may provide clues to the mechanisms of diuretics.

关键词： Urinary proteome Diuretics Biomarkers

Hierarchical predictive energy management strategy for fuel cell buses entering bus stops scenario

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Green Energy and Intelligent Transportation 2023年第4期2卷 1-12页

作者： Mei Yan Hongyang Xu menglin li Hongwen He Yunfei Bai School of Vehicle and Energy Yanshan UniversityHeibei066004China National Engineering Laboratory for Electric Vehicles School of Mechanical EngineeringBeijing Institute of TechnologyBeijing100081China School of Engineering University of WarwickCoventryCV47ALUnited Kingdom

This paper aims to answer how to use traffic information to design energy management strategies for fuel cell buses in a networked environment.For the buses entering the bus stops scenario,this paper proposes a hierarchical energy management strategy for fuel cell buses,which considers the traffic information near the bus stops.In the upper-level trajectory planning stage,the optimal SOC trajectory under various historical traffic conditions is solved through dynamic planning.The traffic information and the best SOC trajectory are mapped through BiLSTM,which can achieve fast,real-time long-term SOC reference.In the lower-level real-time predictive energy management strategy,the optimal SOC is used as the state reference to guide the predictive energy management of fuel cell buses when entering the bus stops.Simulation results show that compared with the strategy without SOC trajectory reference,the life cost of the proposed strategy is reduced by 13.8%,and the total cost is reduced by 3.61%.The SOC of the proposed strategy is closer to the DP optimal solution.

关键词： Fuel cell bus Entering the bus stops scenario Predictive energy management strategy Traffic information Velocity planning SOC trajectory

海岸带城市蓝绿空间碳汇基础设施网络分析——以广西北部湾为例

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广西科学 2024年第2期31卷 213-223页

作者：李萱龚苑红覃盟琳朱梓铭广西大学林学院广西南宁530004 广西大学土木建筑工程学院广西南宁530004 广西大学土木建筑工程学院人居环境设计研究中心广西南宁530004

为探讨蓝绿基础设施(Blue-Green Infrastructure,BGI)碳汇服务功能有益于指引城市碳中和目标建设,本研究以广西北部湾海岸带城市为例,运用形态学空间格局分析(Morphological Spatial Pattern Analysis,MSPA)法、连通性分析法以及电路理... 详细信息

为探讨蓝绿基础设施(Blue-Green Infrastructure,BGI)碳汇服务功能有益于指引城市碳中和目标建设,本研究以广西北部湾海岸带城市为例,运用形态学空间格局分析(Morphological Spatial Pattern Analysis,MSPA)法、连通性分析法以及电路理论,构建蓝绿基础设施碳汇网络,讨论对应的固碳增汇对策。结果表明:2020年研究区蓝绿空间碳汇总量为735524.09 tC·a^(-1),其中绿色空间碳汇总量为588680.06 tC·a^(-1),蓝色空间碳汇总量为146844.03 tC·a^(-1),单位面积碳汇量“蓝”高于“绿”;共提取63个碳汇源地斑块,20个核心源地斑块,绿色空间核心源地总面积为6814.31 km^(2),蓝色空间为899.05 km^(2),核心源地主要分布在东西两侧及南部沿海地带;共提取出24条生态廊道,绿廊共长122.21 km,蓝廊为52.75 km,呈环状分布,中南部地区分布较密,连通性强。本研究结果可为“碳达峰与碳中和”(简称“双碳”)背景下海岸带城市的保护与可持续发展提供建设思路。

关键词：海岸带城市蓝绿空间碳汇基础设施广西北部湾形态学空间格局分析电路理论