检索结果-南通市图书馆

Science China Chemistry 2008年第9期51卷 848-852页

作者： CHEN Meiling, QU YuanYuan, yang li & gao Hong Laboratory of Marine Coatings, Dalian Jiaotong University, Dalian 116028, China Laboratory of Marine Coatings Dalian Jiaotong University Dalian China

Antifouling coatings are used to improve the speed and energy efficiency of ships by preventing or- ganisms, such as barnacles and weed, building up on the underwater hull and helping the ships movement through the water. Typically, marine coatings are tributyltin self-polishing copolymer paints containing toxic molecules called biocides. They have been the most successful in combating bio- fouling on ships, but their widespread use has caused severe pollution in the marine ecosystem. The low surface energy marine coating is an entirely non-toxic alternative, which reduces the adhesion strength of marine organisms, facilitating their hydrodynamic removal at high speeds. In this paper, the novel low surface energy non-toxic marine antifouling coatings were prepared with modified acrylic resin, nano-SiO2, and other pigments. The effects of nano-SiO2 on the surface structure and elastic modulus of coating films have been studied, and the seawater test has been carried out in the Dalian Bay. The results showed that micro-nano layered structures on the coating films and the lowest surface energy and elastic modulus could be obtained when an appropriate mass ratio of resin, nano-SiO2, and other pigments in coatings approached. The seawater exposure test has shown that the lower the sur- face energy and elastic modulus of coatings are, the less the marine biofouling adheres on the coating films.

关键词： non-toxic antifouling coating low surface energy elastic modulus nano-SiO2

Nickel-modified In_(2)O_(3) with inherent oxygen vacancies for CO_(2) hydrogenation to methanol

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第5期67卷 1715-1728页

作者： Zixuan Zhou Yuchen Wang Yuanjie Bao Haiyan yang Jiong li Chunran Chang Shenggang li Peng gao CAS Key Laboratory of Low-Carbon Conversion Science and Engineering Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201210China University of Chinese Academy of Sciences Beijing 100049China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China Shaanxi Key Laboratory of Low Metamorphic Coal Clean Utilization School of Chemistry and Chemical EngineeringYulin UniversityYulin 719000China

Methanol synthesis is one of the most important industrially-viable approaches for carbon dioxide(CO_(2)) utilization, as the produced methanol can be used as a platform chemical for manufacturing green fuels and chemicals. The In_(2)O_(3) catalysts are ideal for sustainable methanol synthesis and have received considerable attention. Herein, Co-, Ni-and Cu-modified In_(2)O_(3) catalysts were fabricated with high dispersion and high stability to improve the hydrogenation performance. The Ni-promoted In_(2)O_(3) catalyst in the form of high dispersion possessed the largest amount of oxygen vacancies and the strongest ability for H_(2) activation, leading to the highest CO_(2) conversion and space time yield of methanol of 0.390 g_(Me OH)g_(cat)^(-1)h^(-1) with CH_(3)OH selectivity of 68.7%. In addition, the catalyst exhibits very stable performance over 120 h on stream, which suggests the promising prospect for industrial applications. Further experimental and theoretical studies demonstrate that surface Ni doping promotes the formation of oxygen defects on the In_(2)O_(3) catalyst, although it also results in lower methanol selectivity. Surprisingly, subsurface Ni dopants are found to be more beneficial for methanol formation than surface Ni dopants, so the Nipromoted In_(2)O_(3)catalyst with a lower surface Ni content at the similar Ni loading can reach higher methanol selectivity and productivity. This work thus provides theoretical guidance for significantly improving the CO_(2) reactivity of In_(2)O_(3)-based catalysts while maintaining high methanol selectivity.

关键词： carbon dioxide hydrogenation methanol synthesis indium oxides Ni doping sites transition metal promoters

Strain-promoted S-arylation and alkenylation of sulfinamides using arynes and cyclic alkynes

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第3期67卷 928-935页

作者： Xi Zou Boming Shen gao-lin li Qian liang Yanhua Ouyang Binghe yang Peiyuan Yu Bing gao State Key Laboratory of Chemo/Bio-Sensing and Chemometrics College of Chemistry and Chemical EngineeringInstitute of Chemical Biology and NanomedicineHunan UniversityChangsha 410082China Department of Chemistry and Shenzhen Grubbs Institute Guangdong Provincial Key Laboratory of CatalysisSouthern University of Science and TechnologyShenzhen 518055China

The conversion of commercially available chiral sulfinamides into pharmaceutically useful chiral sulfoximines via direct SIVfunctionalization is synthetically attractive but challenging due to the competitive reaction of N-functionalization. Herein, we disclose a novel strain-release strategy to access stereospecific and chemoselective SIV-arylation and alkenylation of sulfinamides using arynes and strained cyclic alkynes. This method tolerates an unprecedented chemical diversity of functional groups attached to the nitrogen center(N-R). The origin of the high SIV-selectivity is elucidated by density functional theory calculations, suggesting a stepwise mechanism for the aryne substrates and a concerted mechanism for the cyclic alkynes.

关键词： arylation alkenylation sulfoximines sulfinamides arynes

Advances in Polysaccharide-Based Microneedle Systems for the Treatment of Ocular Diseases

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第12期16卷 233-284页

作者： Qingdong Bao Xiaoting Zhang Zhankun Hao Qinghua li Fan Wu Kaiyuan Wang yang li Wenlong li Hua gao State Key Laboratory Cultivation Base Shandong Provincial Key Laboratory of OphthalmologyEye Institute of Shandong First Medical UniversityQingdao 266071People’s Republic of China State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002People’s Republic of China Eye Hospital of Shandong First Medical University Jinan 250021People’s Republic of China College of Ophthalmology Shandong First Medical UniversityJinan 250000People’s Republic of China Departments of Diagnostic Radiology SurgeryChemical and Biomolecular Engineeringand Biomedical EngineeringYong Loo Lin School of Medicine and College of Design and EngineeringNational University of SingaporeSingapore 119074Singapore

The eye,a complex organ isolated from the systemic circulation,presents significant drug delivery challenges owing to its protective mechanisms,such as the blood-retinal barrier and corneal *** drug administration methods often fail to sustain therapeutic levels and may compromise patient safety and *** microneedles(PSMNs)have emerged as a transformative solution for ophthalmic drug ***,a comprehensive review of PSMNs in ophthalmology has not been published to *** this review,we critically examine the synergy between polysaccharide chemistry and microneedle technology for enhancing ocular drug *** provide a thorough analysis of PSMNs,summarizing the design principles,fabrication processes,and challenges addressed during fabrication,including improving patient comfort and *** also describe recent advances and the performance of various PSMNs in both research and clinical ***,we review the current regulatory frameworks and market barriers that are relevant to the clinical and commercial advancement of PSMNs and provide a final perspective on this research area.

关键词： Ocular delivery Polysaccharide Microneedles Drug administration

Study on the atmospheric heat engine efficiency and heat source characteristics of the Qinghai-Tibet Plateau in summer

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第1期67卷 117-133页

作者： Yujie li Xiaoqing gao Yaoming MA Zeyong HU Zhenchao li liwei yang Xiao JIN Xiyin ZHOU Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions of Chinese Academy of Sciences Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Tianjin Key Laboratory for Oceanic Meteorology Tianjin Institute of Meteorological ScienceTianjin 300074China Institute of Tibetan Plateau Research Chinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

There are many types of atmospheric heat engines in land-air *** accurate definition,calculation and interpretation of the efficiency of atmospheric heat engines are key to understanding energy transfer and transformation of landair *** atmosphere over the Qinghai-Tibet Plateau(QTP)in summer can be regarded as a positive heat *** study of the heat engine efficiency is helpful to better understand land-air interaction and thermal-dynamic processes on the *** also provides a new perspective to explain the impact of the QTP on the climate of China,East Asia and even the *** this paper,we used MOD08 and ERA5 reanalysis data to calculate the atmospheric heat engine efficiency,surface heat source and atmospheric heat source on the QTP in summer(May to September)from 2000 to *** average atmospheric heat engine efficiency on the QTP in summer from 2000 to 2020 varies between 1.2%and 1.5%,which is less than 1.6%;the heat engine efficiency in summer is higher than that in June,July and August;the Qaidam Basin is the region with the highest atmospheric heat engine efficiency,followed by the western *** mean surface heat source on the QTP in summer from 2000 to 2020 is 96.0 W m^(−2),the atmospheric heat source is 90.7 W m^(−2),and the release of precipitation condensation latent heat is the most important component of the atmospheric heat source on the QTP in *** is a strong and significant positive correlation between the atmospheric heat engine efficiency and the surface heat source on the QTP in *** precipitation condensation latent heat is the most important component of the atmospheric heat source in summer and can reflect the precipitation *** is a strong and significant negative correlation between the atmospheric heat engine efficiency and the atmospheric heat source on the QTP in summer.

关键词： Qinghai-Tibet Plateau Climate change Land-air system Atmospheric heat engine Heat source on the Qinghai-Tibet Plateau

Cobalt-doped TiO_(2)@C hierarchical nanocomposites derived from Ti_(3)C_(2) MXene as cathodes for hybrid magnesium-lithium batteries

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第1期17卷 253-261页

作者： Xiaohui li Yakun Tang Lang liu Yue Zhang yang gao Mao Qian Wenjie Ma State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources College of ChemistryXinjiang UniversityUrumqi 830017China

TiO_(2)has been explored in hybrid magnesium-lithium batteries(HMLBs)due to the advantages of low self-discharge and small volume expansion during ion ***,how to improve the inherently low ionic and electrical conductivity of TiO_(2)is the problem that needs to be *** this work,a smart strategy is adopted to prepare cobalt-doped TiO_(2)@C(Co^(4+)-TiO_(2)@C)hierarchical nanocomposite derived from Co(II)(OH)n@*** with TiO_(2)@C(without cobalt doping),Co^(4+)-TiO_(2)@C shows the highest specific capacity(154.7 mAh·g^(-1)at 0.1 A·g^(-1)after 200 cycles)and extraordinary rate performance in *** excellent electrochemical performance of Co4+-TiO_(2)@C is ascribed to the synergistic effect of the hierarchical structure and *** experimental results and density functional theory(DFT)calculation reveal that the cobalt-doping has effectively improved the electronic conductivity and reduced the li+migration *** work provides a new insight to design TiO_(2)-based cathode materials with high-performance in HMLBs.

关键词： Ti_(3)C_(2)MXene TiO_(2) hybrid magnesium-lithium batteries hierarchical structure cobalt-doping

Particle size characterization and sources of sediments in the Uzhumqin sand dunes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第8期21卷 2631-2645页

作者： ZHANG Hao liU yang DANG Xiaohong MENG Zhongju li Shuangli gao Yong Inner Mongolia Agricultural University Inner Mongolia 010018China Inner Mongolia Autonomous Region Water Resources Research Institute Hohhot 010020China

Sediment constitutes the fundamental basis for forming and evolving aeolian *** characteristics of sediment particle size offer insights into the development and evolution of sandy terrain,making their study critical to understanding aeolian geomorphology and sand *** this study,we combined high-density collection of surface sediments in the Uzhumqin sand dunes and GIS spatial analysis to analyze the particle size parameters and changes in the spatial distribution of surface sediments in this *** addition,we used an end-member analysis to identify the potential sources of the *** results showed that surface sediments in the Uzhumqin sand dunes had distinct spatial *** and coarse grain sands dominated the sediments in the dunes,and the mean grain size and the sorting coefficient generally increased along the prevailing wind direction,with high values in individual areas related to factors such as material sources and vegetation *** was strongly influenced by factors such as landform change and human activity,and spatial variability became more *** and the soil fractal dimension showed generally decreasing trends along the prevailing wind *** dune fixation,the contents of clay and powder particles in the soil increased;the mean particle size,the sorting coefficient,and the fractal dimension of the soil gradually increased,and the skewness and kurtosis gradually *** end-member analysis results indicated the existence of five end-members(EM)in the dune *** 1 was a mixed component of wind-deposited fine sands and nearby fluvial *** 2 was the main component of sediments in the study area and was the result of sorting lake sediments by wind action and by the local *** 3 may be a product of river flood *** 4 and EM 5 had coarser grain *** 4 was a lake-phase sediment product influenced by topographic and vegetation cover factors,and EM

关键词： Sediment Particle size Spatial differences End-member analysis Uzhumqin sand dunes

Dual sliding mode coordinated control of manipulator grasping system with visual assistance

在线全文

学校读者我要写书评

暂无评论

Control Theory and Technology 2024年第1期22卷 106-121页

作者： Pengxin Zhang Haisheng Yu Xiangxiang Meng Zhe li Qing yang Xunkai gao College of Automation Qingdao UniversityQingdao266071ShandongChina Shandong Province Key Laboratory of Industrial Control Technology Qingdao266071ShandongChina

The operation efficiency of the manipulator is placed in the primary position in automatic production. This paper proposes a coordinated control strategy for joint servo and visual servo to enable timely transfer and accurate gripping in the working area. Aiming at the issues of chattering and slow convergence of traditional sliding mode controller, a fast variable power reaching rate on the basis of the non-singular fast terminal sliding mode controller is proposed, which can effectively reduce the convergence time and chattering. For the purpose of addressing the problem that the traditional visual servo control method is sensitive to the environment, a visual servo controller based on integral sliding mode is proposed, to ensure the favorable positioning accuracy of the manipulator. Based on the two proposed controllers mentioned above, a coordinated control strategy is used to implement the control of the manipulator. Finally, the upper computer software is developed using the C# programming language to monitor the workstation. The feasibility of the above-mentioned method is verified through multiple simulations and experiments.

关键词： Automatic production Joint servo Visual servo Coordinated control Non-singular fast terminal sliding mode Integral sliding mode

Construction of smart propellant with multi-morphologies

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第3期33卷 180-185页

作者： Weitao yang Yuchen gao Rui Hu Manman li Fengqi Zhao He Jiang Xuan Zhang Xi’an Modern Chemistry Research Institute Xi’an710065China Northwestern Polytechnical University Xi’an710072China

Smart materials,which exhibit shape memory behavior in response to external stimuli,have shown great potential for use in biomedical *** this study,an energetic composite was fabricated using a UV-assisted DIW 3D printing technique and a shape memory material(SMP)as the *** composite has the ability to reduce the impact of external factors and adjust gun propellant combustion *** composition and 3D printing process were delineated,while the internal structure and shape memory performance of the composite material were *** energetic SMP composite exhibits an angle of reversal of 18 s at 70°,with a maximum elongation typically reaching up to 280% of the original length and a recovery length of approximately 105%during ten ***,thermal decomposition and combustion behavior were also demonstrated for the energetic SMP composite.

关键词： Smart material Gun propellants Multi-morphologies Self-regulation

Effect of electron beam irradiation on surface molecule and flashover voltage of epoxy composites

在线全文

学校读者我要写书评

暂无评论

High Voltage 2024年第3期9卷 528-536页

作者： Mingru li Huan Niu Kai Shang Jianyu Lang Yafang gao Bingnan li Jiuhui Zhao Zhen li yang Feng Shengtao li State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anShaanxiChina Key Laboratory of Engineering Dielectrics and Its Application Ministry of EducationHarbin University of Science and TechnologyHarbinHeilongjiangChina

The unsatisfactory insulating properties of solid–gas interfaces seriously restrict the development of high-voltage electrical equipment and threaten their power supply ***-beam irradiation(EBI)can effectively improve the surface flashover voltage of ***,the underlying mechanism of EBI in tailoring the surface trap and improving the flashover voltage remains *** this study,the surface morphologies and chemical compositions of epoxy composites treated with EBI were *** addition,the surface wetting properties,surface charge migration pa-rameters,and surface flashover voltages were experimentally *** was found that EBI aggravated the surface morphology,changed the surface chemical components,and repressed surface charge *** a result,the contact angle was reduced from 103.7°to 78.43°,and the flashover voltage in SF6 was increased from 35.26 to 38.90 *** calculations showed that the newly generated C–O–H and C=O bonds on the surface molecules after EBI formed charge centres at the molecular electrostatic potential,which enhanced the trapping effect of the surface deep *** a result,surface charge migration was repressed,and the surface flashover voltage was *** study could promote the further development of EBI on materials modification.

关键词： composites surface beam