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A Mild and Efficient Procedure for the Preparation of Chromone-2-carboxylates

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Chinese Chemical Letters 2006年第8期17卷 1005-1008页

作者： Juan Hong YU Yu She YANG Ru yun ji State Key Laboratory of Drug Research Shanghai Institute of Materia Medica Shanghai Institutes for Biological Sciences the Chinese Academy of Sciences Shanghai 201203

A mild and efficient procedure to build up various chromone-2-carboxylates was developed. Condensation of diverse 2-hydroxyacetophones with tetr-butyl oxalate in the presence of sodium ethoxide could be accomplished rapidly under mild condition. Cyclodehydration was carried out to achieve chromone-2-carboxylates in one-pot with impressive yield. Advantages over conventional methods with diethyl oxalate were observed in yield and reaction time.

关键词： Chromone-2-carboxylates tea-butyl ethyl oxalate diethyl oxalate.

Optimal distributed power allocation for a new spectrum sharing paradigm in cognitive radio networks

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The Journal of China Universities of Posts and Telecommunications 2012年第3期19卷 37-43页

作者： ZHANG Xiao-liang ji Hong LI Xi DAI Li-yun Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and Telecommunications Beijing 100876 China School of Software and Communication Engineering Jiangxi University of Finance and Economics Nanchang 330013 China

The problem of power allocation in cognitive radio networks plays an important role to improve the efficiency of spectrum utilization. However, most of previous works focus on the power allocation for secondary users in spectrum sharing overlay or spectrum sharing underlay, which needs to frequently handoff between the idle spectrum bands or considers the interference constraints in all spectrum bands respectively. In order to reduce the handoff and fully utilize the spectrum resource, we propose a new spectrum sharing paradigm which not only can just need to adjust the transmit power in spectrum bands instead of frequently handoff between idle spectrum bands, but can fully utilize the spectrum resource as we only consider the interference power constraints in active spectrum bands rather than in all spectrum bands. Then based on this new spectrum sharing paradigm and the constraint conditions, we study the distributed power allocation for secondary users and formulate the optimization problem as a non-cooperative game problem, after that the variational inequality approach is used to solve this game problem and a Nash equilibria solution is got, finally simulation results are illustrated to demonstrate the performance of the proposed scheme.

关键词： resource allocation efficiency handoff spectrum sharing paradigm

SELF-ASSEMBLY OF LINEAR TRIBLOCK COPOLYMERS UNDER CYLINDRICAL NANOPORE CONFINEMENTS

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Chinese Journal of Polymer Science 2013年第1期31卷 122-138页

作者： Wen-juan Qiu 李士本 Yong-yun ji Lin Xi Zhang Department of Physics Wenzhou University Department of Physics Zhejiang University

The self-assembly of linear ABC triblock copolymers under cylindrical confinements is investigated in two- dimensional space using the real-space self-consistent field theory. The effects of confinement degrees and preferential strengths on the triblock copolymer phase behaviors with special polymer parameters are first considered. On one hand, different confinement degrees cause different phase behaviors in nanopores with the neutral surfaces. Moreover, the strongly preferential surface fields can surpass the confinement degrees and volume fractions in determing the confined phase behaviors. On the other hand, in contrast, confined morphologies are more sensitive to the variations in the A-preferential surface field strength. Subsequently, the incompatibility degrees between different blocks are systematically varied under cylindrical nanopore confinements. Under cylindrical nanopore confinements, the morphologies are very sensitive to the variations in the incompatibility degrees. Meanwhile, nanopore confinements can affect order-disorder and order-order transition points in the bulk. The corresponding free, internal, and entropic energies as well as the order parameters are also quantificationally examined to deeply investigate the confined phase mechanisms, and a number of morphological transitions are confirmed to be of first-order. These findings may guide the design of novel nanostructures based on triblock copolymers by introducing confinements.

关键词： Triblock copolymers Cylindrical confinements Self-assembly Self-consistent field theory.

A multifunctional optical-thermal logic gate sensor array based on ferroelectric BiFeO_(3) thin films

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InfoMat 2023年第5期5卷 111-120页

作者： Li Wu yun ji Huiyu Dan Chris RBowen Ya Yang CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijingthe People's Republic of China Center on Nanoenergy Research School of Physical Science and TechnologyGuangxi UniversityNanningthe People's Republic of China Department of Mechanical Engineering University of BathBathUK

The growing need to process a diverse range of data has ignited effort in developing new multifunctional logic gate *** this article,we report a new form of all-in-one logic gate system that exploits the photoresponsivity of a self-powered multifunctional BiFeO_(3)(BFO)sensor *** BFO sensor can not only detect both light intensity and temperature,but it can also execute three common logic gates of“AND”,“OR”,and“NOT”by converting optical and thermal inputs into electrical *** diverse functionality of the BFO logic gate sensor array utilizes the unique light-and temperaturecontrolled energy band structure and carrier behavior of the BFO *** demonstrate the potential,a 3×3 logic gate sensor matrix is developed,which successfully detected light and temperature distributions,and accurately produced the three basic logic gate *** work provides a new route to construct highly integrated multifunctional electronic devices for the advancement of large sensing,communication,and computing operations.

关键词： BiFeO_(3) logic gate optical-thermal photocurrent photovoltage

Coupling Enhancement of a Flexible BiFeO_(3) Film-Based Nanogenerator for Simultaneously Scavenging Light and Vibration Energies

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Nano-Micro Letters 2022年第12期14卷 137-150页

作者： Xiao Han yun ji Li Wu Yanlong Xia Chris RBowen Ya Yang CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-Nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 101400People’s Republic of China Department of Mechanical Engineering University of BathBath BA27AKUK School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing 100049People’s Republic of China Center On Nanoenergy Research School of Physical Science and TechnologyGuangxi UniversityNanning 530004People’s Republic of China

Coupled nanogenerators have been a research hotspot due to their ability to harvest a variety of forms of energy such as light,mechanical and thermal energy and achieve a stable direct current *** films are frequently investigated for photovoltaic applications due to their unique photovoltaic properties and bandgap-independent photovoltage,while the flexoelectric effect is an electromechanical property commonly found in solid ***,we effectively construct a new form of coupled nanogenerator based on a flexible BiFeO_(3) ferroelectric film that combines both flexoelectric and photovoltaic effects to successfully harvest both light and vibration *** device converts an alternating current into a direct current and achieves a 6.2% charge enhancement and a 19.3%energy enhancement to achieve a multi-dimensional"1+1>2"coupling enhancement in terms of current,charge and *** work proposes a new approach to the coupling of multiple energy harvesting mechanisms in ferroelectric nanogenerators and provides a new strategy to enhance the transduction efficiency of flexible functional devices.

关键词： Ferroelectric film Coupled nanogenerators Photovoltaic effect Flexoelectric effect Energy collection

Simulation of temporal and spatial change of N_2O emissions in the Yangtze River Delta

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Journal of Environmental Sciences 2005年第4期17卷 686-690页

作者： LIUjian-dong ZHOUXiu-ji CHENDe-liang OUYANGZhi-yun WANGXiao-ke AchbergerChristine EarthScienceCenter GothenburgUniversitySweden／／ChineseAcademyofMeteorologicalSciencesBeijing100081China ChineseAcademyofMeteorologicalSciences Beijing100081China EarthScienceCenter GothenburgUniversitySweden／／Laborato~forClimateStudies／NationalClimateCenterChinaMeteorologicalAdministrationBeijing100081China ResearchCenterforEco-EnvironmentalSciences ChineseAcademyofSciencesBeijing100085China EarthScienceCenter GothenburgUniversitySweden

A biogeochemical model(DNDC) is combined with a plant ecological model to estimate N_2O emission from rice paddy fields in the Yangtze River Delta region. The model is driven by local meteorological, soil, and physiological data and is validated for 1999 and 2000 at a site in the region, which showed that the simulated N_2O emissions agree fairly well with the observed data. This adds some confidence in the estimated N_2O emissions during 1950 and 2000 in the Hangzhou Region. A significant correlation between the N_2O emissions and the population for the Hangzhou Region is found, which is due to a combination of increased application of fertilizers and cultivated area. Such a correlation can not be established for the whole Yangtze River Delta region when the data of both urban and rural areas are included. However, when the data from the heavily urbanized areas are excluded, a significant correlation between population and N_2O emissions emerges. The results show clearly that both the temporal and the spatial N_2O emissions have significant positive relationship with population under traditional farming practice. These results have implications for suitable mitigation options towards a sustainable agriculture and environment in this region.

关键词： simulation temporal and spatial N_2O emissions Yangtze River Delta,China

Identification of emission sources of umbral flashes using phase congruency

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Research in Astronomy and Astrophysics 2014年第8期14卷 1001-1010页

作者： Song Feng Lan Yu yun-Fei Yang Kai-Fan ji yunnan Key Laboratory of Computer Technology Application/Faculty of Information Engineering and Automation Kunming University of Science and Technology Key Laboratory of Solar Activity National Astronomical ObservatoriesChinese Academy of Sciences Department of Information Engineering Yunnan Land and Resources Vocational College

The emission sources of umbral flashes （UFs） are believed to be closely related to running umbral and penumbral waves, and are concluded to be associated with umbral dots in the solar photosphere. Accurate identification of emission sources of UFs is crucial for investigating these physical phenomena and their inherent relationships. A relatively novel model of shape perception, namely phase congruency （PC）, uses phase information in the Fourier domain to identify the geometrical shape of the region of interest in different intensity levels, rather than intensity or gradient. Previous studies indicate that the model is suitable for identifying features with low contrast and low luminance. In the present paper, we applied the PC model to identify the emission sources of UFs and to locate their positions. For illustrating the high performance of our proposed method, two time sequences of Ca n H images derived from the Hinode/SOT on 2010 August 10 and 2013 August 20 were used. Furthermore, we also compared these results with the analysis results that are identified by the traditional/classical identification methods, including the gray-scale adjusted technique and the running difference technique. The result of our analysis demonstrates that our proposed method is more accurate and effective than the traditional identification methods when applied to identifying the emission sources of UFs and to locating their positions.

关键词： techniques image processing -- Sun chromosphere -- Sun photo- sphere -- sunspots -- convection

Crystal Structure of a Novel Complex Na_4[Y(PDC)_2(BTC)]·5H_2O with One-Dimensional Helical Network Structure (H2PDC = 2,6-Pyridinedicarboxylic acid)( H_3BTC = 1,3,5-Benzenetricarboxylic acid )

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Chinese Journal of Structural Chemistry 2005年第10期24卷 1181-1185页

作者： XUE Xu-Fei CHE yun-Xia XUE Lin ZHENG ji-Min Department of Chemistry Nankai University Tianjin 300071 China

A novel title complex, C23H19N2O19Na4Y （Mr= 808.27）, has been synthesized by hydrothermal reaction and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/n with a = 13.560（3）, b = 14.016（3）, c = 14.948（4） A, β = 99.492（4）°, Z = 4, V = 2802.2（12） A^3, Dc = 1.916 g/cm^3,μ（MoKα） = 2.241 mm^-1, F（000） = 1624, the final R = 0.0337 and wR = 0.0828 for 4044 observed reflections（I〉 2σ（I））. In the crystal, each eight- coordinated Y（Ⅲ） atom is linked by carboxyl groups of BTC to form a one-dimensional helical network structure.

关键词： 1,3,5-benzenetricarboxylic acid 2,6-pyridinedicarboxylic acid,hydrothermal synthesis crystal structure

IN SITU ETHYLENE COPOLYMERIZATION WITH AN OLEFIN-TYPE MONOMER FOR ONE-POT SYNTHESIS OF POLYETHYLENE TETHERED ON MULTI-WALLED CARBON NANOTUBES

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Chinese Journal of Polymer Science 2013年第10期31卷 1329-1333页

作者： ji-jun Tang Shi-yun Li Yan-hui Wang Tao Tang Department of Materials Science and Engineering Jiangsu University of Science and Technology State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of Sciences

A one-pot procedure for the synthesis of polyethylene tethered on multi-walled carbon nanotubes by in situ ethylene copolymerization with an olefin-type comonomer, tr-alkene functionalized multi-walled carbon nanotubes （MW- CH = CH2） is reported. The covalent linkage between polyethylene and multi-walled carbon nanotubes is demonstrated. The MWCNTs are chemically oxidized first by a strong oxidizing agent and then functionalized with chlorocarbonyl groups （MW--COC1） via reacting with thionyl chloride. The MW--CH=CH2 are obtained by esterification of co-undecylenyl alcohol with MW--COCI. The MW--CH = CH2 may serve as olefin-type comonomers to fiLrther synthesize core-shell structured copolymers with a multi-walled carbon nanotubes core grafted with side chains of polyethylene via rac-（en）（THInd）2ZrC12 copolymerization catalyst. The core-shell structured nanocomposites were characterized by means of 1H-NMR, SEM, FTIR and TGA. The results confirmed the formation of polyethylene chains growing from the surface of multi-walled carbon nanotubes.

关键词： Carbon nanotubes Copolymerization Polyethylene Nanocomposite.