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| 1 | Non-uniform distribution of gas-solid flow through six parallel cyclones in a CFB system: An experimental study显示文摘In large-scale circulating fluidized bed (CFB) boilers, it is common to use multiple cyclones in parallel for the capture of solids, assuming that gas-solid flow to be the same in the cyclones. This article presents a study investigating gas-solid flow through six parallel cyclones in a CFB cold test rig. The six cyclones were located asymmetrically on the left and right walls of the riser. Solid volume fraction and particle velocity profiles at the riser outlets and in the horizontal ducts were measured using a fiber optical probe. Cyclone pressure drop and solid circulating rate were measured for each individual cyclone. Measurements showed good agreement as to the non-uniform distribution of the gas-solid flow, which occurred mainly across the three cyclones on one side: the middle cyclones on both sides had higher particle velocities. Conversely, the solid volume fractions, solid fluxes and solid circulating rates of the middle cyclones were lower than those of the other four cyclones. The apparent reason for the flow non-uniformity among the cyclones is the significant flow non-uniformity at the riser outlets. Under typical operating conditions, the solid volume fractions at the riser outlets had a deviation of up to 26% whereas the solid circulating rates at the stand pipes, 7%. These results are consistent with most other studies in the literature. | Xinglong Zhou Leming Cheng Qinhui Wang Zhongyang Luo Kefa Cen | 2012 | Particuology2012,10,2: | 31 |
| 2 | Intelligent and connected vehicles: Current status and future perspectives显示文摘Intelligent connected vehicles(ICVs) are believed to change people's life in the near future by making the transportation safer,cleaner and more comfortable. Although many prototypes of ICVs have been developed to prove the concept of autonomous driving and the feasibility of improving traffic efficiency, there still exists a significant gap before achieving mass production of high-level ICVs. The objective of this study is to present an overview of both the state of the art and future perspectives of key technologies that are needed for future ICVs. It is a challenging task to review all related works and predict their future perspectives, especially for such a complex and interdisciplinary area of research. This article is organized to overview the ICV key technologies by answering three questions: what are the milestones in the history of ICVs; what are the electronic components needed for building an ICV platform; and what are the essential algorithms to enable intelligent driving? To answer the first question, the article has reviewed the history and the development milestones of ICVs. For the second question, the recent technology advances in electrical/electronic architecture, sensors, and actuators are presented. For the third question, the article focuses on the algorithms in decision making, as the perception and control algorithm are covered in the development of sensors and actuators. To achieve correct decision-making, there exist two different approaches: the principle-based approach and data-driven approach. The advantages and limitations of both approaches are explained and analyzed. Currently automotive engineers are concerned more with the vehicle platform technology, whereas the academic researchers prefer to focus on theoretical algorithms. However, only by incorporating elements from both worlds can we accelerate the production of high-level ICVs. | YANG DianGe JIANG Kun ZHAO Ding YU ChunLei CAO Zhong XIE ShiChao XIAO ZhongYang JIAO XinYu WANG SiJia ZHANG Kai | 2018 | Science China(Technological Sciences)2018,61,10: | 31 |
| 3 | ESTIMATION OF ECOLOGICAL SERVICE VALUES OF WETLANDS IN SHANGHAI, CHINA显示文摘Shanghai is a coastal metropolitan city with various types of natural wetlands, which account for 23.5% of its total area. According to the definition of wetland in Ramsar Convention on Wetlands, the wetlands of Shanghai were classified into 4 types: coastal, riverine, lacustrine, and reservoir and pond wetlands. In order to examine the roles of wetlands in the life-support system of Shanghai, we calculated the area of each type of the wetlands using GIS technique, and then measured the ecological service values of different ecosystems in Shanghai based on the classification of ecosystem services proposed by COSTANZA et al. (1997). The estimated annual value of ecosystem services in the study area was 7.3×109US$/a for the total area of 1 356 700ha, among which about 97% was provided by the wetlands. Effective conservation and management of wetlands are therefore crucial to Shanghai’s sustainable development. The limitations of the evaluation method for ecosystem service value were also discussed in the present paper. | LIBo ZHONGYang NAKAGOSHINobukazu CHENJia-kuan | 2005 | Chinese Geographical Science2005,15,2: | 24 |
| 4 | Simultaneous oxidation of NO,SO_2 and Hg^0 from flue gas by pulsed corona discharge显示文摘A process capable of simultaneously oxidizing NO,SO2,and Hg0 was proposed,using a high-voltage and short-duration positive pulsed corona discharge.By focusing on NO,SO2,and Hg0 oxidation effciencies,the influences of pulse peak voltage,pulse frequency,initial concentration,electrode number,residence time and water vapor addition were investigated.The results indicate that NO,SO2 and Hg0 oxidation effciencies depend primarily on the radicals(OH,HO2,O) and the active species(O3,H2O2,etc.) produced by the pulsed corona discharge.The NO,SO2 and Hg0 oxidation effciencies could be improved as pulse peak voltage,pulse frequency,electrode number and residence time increased,but they were reduced with increasing initial concentrations.By adding water vapor,the SO2 oxidation effciency was improved remarkably,while the NO oxidation effciency decreased slightly.In our experiments,the simultaneous NO,SO2,and Hg0 oxidation effciencies reached to 40%,98%,and 55% with the initial concentrations 479 mg/m3,1040 mg/m3,and 15.0 μg/m3,respectively. | XU Fei,LUO Zhongyang,CAO Wei,WANG Peng,WEI Bo,GAO Xiang,FANG Mengxiang,CEN Kefa State key Laboratory of Clean Energy Utilization,Zhejiang University,Hangzhou 310027,China. | 2009 | Journal of Environmental Sciences2009,21,3: | 22 |
| 5 | A Flexible Multi-Layer Map Model Designed for Lane-Level Route Planning in Autonomous Vehicles显示文摘An increasing number of drivers are relying on digital map navigation systems in vehicles or mobile phones to select optimal driving routes in order to save time and improve safety. In the near future, digital map navigation systems are expected to play more important roles in transportation systems. In order to extend current navigation systems to more applications, two fundamental problems must be resolved: the lane-level map model and lane-level route planning. This study proposes solutions to both problems. The current limitation of the lane-level map model is not its accuracy but its flexibility;this study proposes a novel seven-layer map structure, called as Tsinghua map model, which is able to support autonomous driving in a flexible and efficient way. For lane-level route planning, we propose a hierarchical route-searching algorithm to accelerate the planning process, even in the presence of complicated lane networks. In addition, we model the travel costs allocated for lane-level road networks by analyzing vehicle maneuvers in traversing lanes, changing lanes, and turning at intersections. Tests were performed on both a grid network and a real lane-level road network to demonstrate the validity and efficiency of the proposed algorithm. | Kun Jiang Diange Yang Chaoran Liu Tao Zhang Zhongyang Xiao | 2019 | Engineering2019,5,2: | 14 |
| 6 | Research on coal staged conversion poly-generation system based on fluidized bed显示文摘A new coal staged conversion poly-generation system combined coal combustion and pyrolysis has been developed for clean and high efficient utilization of coal.Coal is the first pyrolysed in a fluidized pyrolyzer.The pyrolysis gas is then purified and used for chemical product or liquid fuel production.Tar is collected during purification and can be processed to extract high value product and to make liquid fuels by hydro-refining.Semi-coke from the pyrolysis reactor is burned in a circulating fluidized bed(CFB)combustor for heat or power generation.The system can realize coal multiproduct generation and has a great potential to increase coal utilization value.A 1 MW poly-generation system pilot plant and a 12 MW CFB gas,tar,heat and power poly-generation system was erected.The experimental study focused on the two fluidized bed operation and characterization of gas,tar and char yields and compositions.The results showed that the system could operate stable,and produce about 0.12 m^(3)/kg gas with 22 MJ/m^(3)heating value and about 10 wt%tar when using Huainan bituminous coal under pyrolysis temperature between 500 and 600℃.The produced gases were mainly H_(2),CH_(4),CO,CO_(2),C_(2)H_(4),C_(2)H_(6),C_(3)H_(6)and C_(3)H_(8).The CFB combustor can burn semi-coke steadily.The application prospect of the new system was discussed. | Mingjiang Ni Chao Li Mengxiang Fang Qinhui Wang Zhongyang Luo Kefa Cen | 2014 | International Journal of Coal Science & Technology2014,1,1: | 13 |
| 7 | Surrogate-Assisted Particle Swarm Optimization Algorithm With Pareto Active Learning for Expensive Multi-Objective Optimization显示文摘For multi-objective optimization problems, particle swarm optimization(PSO) algorithm generally needs a large number of fitness evaluations to obtain the Pareto optimal solutions. However, it will become substantially time-consuming when handling computationally expensive fitness functions. In order to save the computational cost, a surrogate-assisted PSO with Pareto active learning is proposed. In real physical space(the objective functions are computationally expensive), PSO is used as an optimizer, and its optimization results are used to construct the surrogate models. In virtual space, objective functions are replaced by the cheaper surrogate models, PSO is viewed as a sampler to produce the candidate solutions. To enhance the quality of candidate solutions, a hybrid mutation sampling method based on the simulated evolution is proposed, which combines the advantage of fast convergence of PSO and implements mutation to increase diversity. Furthermore, ε-Pareto active learning(ε-PAL)method is employed to pre-select candidate solutions to guide PSO in the real physical space. However, little work has considered the method of determining parameter ε. Therefore, a greedy search method is presented to determine the value ofεwhere the number of active sampling is employed as the evaluation criteria of classification cost. Experimental studies involving application on a number of benchmark test problems and parameter determination for multi-input multi-output least squares support vector machines(MLSSVM) are given, in which the results demonstrate promising performance of the proposed algorithm compared with other representative multi-objective particle swarm optimization(MOPSO) algorithms. | Zhiming Lv Linqing Wang Zhongyang Han Jun Zhao Wei Wang | 2019 | IEEE/CAA Journal of Automatica Sinica2019,6,3: | 13 |
| 8 | Putative hAPN receptor binding sites in SARS_CoV spike protein显示文摘AIM:To obtain the information of ligand-receptor binding between thd S protein of SARS_CoV and CD13, identify the possible interacting domains or motifs related to binding sites, and provide clues for studying the functions of SARS proteins and designing anti-SARS drugs and vaccines. METHODS: On the basis of comparative genomics, the homology search, phylogenetic analyses, and multi-sequence alignment were used to predict CD13 related interacting domains and binding sites sites in the S protein of SARS_CoV. Molecular modeling and docking simulation methods were employed to address the interaction feature between CD13 and S protein of SARS_CoV in validating the bioinformatics predictions. RESULTS:Possible binding sites in the SARS_CoV S protein to CD13 have been mapped out by using bioinformatics analysis tools. The binding for one protein-protein interaction pair (D757-R761 motif of the SARS_CoV S protein to P585-A653 domain of CD13) has been simulated by molecular modeling and docking simulation methods. CONCLUSION:CD13 may be a possible receptor of the SARS_CoV S protein which may be associated with the SARS infection. This study also provides a possible strategy for mapping the possible binding receptors of the proteins in a genome. | YUXiao-Jing LUOCheng LinJian-Cheng HAOPei HEYou-Yu GUOZong-Ming QINLei SUJiong LIUBo-Shu HUANGYin NANPeng LIChuan-Song XIONGBin LUOXiao-Min ZHAOGuo-Ping PEIGang CHENKai-Xian SHENXu SHENJian-Hua ZOUJian-Ping HEWei-Zhong SHITie-Liu ZHONGYang JIANGHua-Liang LIYi-Xue | 2003 | Acta Pharmacologica Sinica2003,24,6: | 13 |
| 9 | Disease profile and plasma neutralizing activity of postvaccination Omicron BA.1 infection in Tianjin,China:a retrospective study显示文摘Dear Editor,SARS-CoV-2 Omicron variant BA.1 first emerged on the Chinese mainland on January 8,2022,in Tianjin and caused a large wave of infections.1 Four rounds of mass testing of its~14 million residents were launched on January 9,12,15,and 20,respectively.As of February 7,2022,a total of 430 individuals were tested positive for Omicron BA.1,with no new infections detected for the following 16 days.In the Chinese mainland,the most delivered vaccines are inactivated vaccines.As of January 8,2022,up to 93.2%of Tianjin’s residents had been vaccinated with at least one dose.2 We investigated the protection conferred by vaccination against Omicron BA.1 by examining the breakthrough infections among vaccinees as compared with unvaccinated cases.Our study population comprised all 430 cases during the outbreak of Omicron BA.1 in Tianjin. | Hong Zheng Yunlong Cao Xiaosu Chen Fengmei Wang Ye Hu Weiliang Song Yangyang Chai Qingqing Gu Yansong Shi Yingmei Feng Shuxun Liu Yan Xie Xiaoliang Sunney Xie Wentao Jiang Zhongyang Shen | 2022 | Cell Research2022,32,8: | 12 |
| 10 | Research Advance in Swarm Robotics显示文摘The research progress of swarm robotics is reviewed in details. The swarm robotics inspired from nature is a combination of swarm intelligence and robotics, which shows a great potential in several aspects. First of all, the cooperation of nature swarm and swarm intelligence are briefly introduced, and the special features of the swarm robotics are summarized compared to a single robot and other multi-individual systems. Then the modeling methods for swarm robotics are described by a list of several widely used swarm robotics entity projects and simulation platforms. Finally, as a main part of this paper, the current research on the swarm robotic algorithms are presented in detail, including cooperative control mechanisms in swarm robotics for flocking, navigating and searching applications. | TAN Ying ZHENG Zhongyang | 2013 | Defence Technology(防务技术)2013,9,1: | 11 |
| 11 | Identification of probable genomic packaging signal sequence from SARS—CoV genome by bioinformatics analysis显示文摘AIM:To predict the probable genomic packaging signal of SARS-CoV by bioinformatics analysis. The derived packaging signal may be used to design antisense RNA and RNA interfere (RANi) drugs treating SARS. methods: Based on the studies about the genomic packaging signals of MHV and BCoV, especially the information about primary and secondary structures, the putative genomic packaging signal of SARS_CoV were analyzed by using bioinformatic tools. Multi-alignment for the genomic sequences was performed among SARS-CoV,MHV,BCoV, PEDV and HCoV 229E. Secondary structures of RNA sequences were also predicted for the identification fo the possible genomic packaging signals. Meanwhile, the N and M proteins of all five viruses were analyzed to study the evolutionary relationship with genomic packaging signals. RESULTS: The putative genomic packaging signal of SARS-CoV locates at the 3′ end of ORF1b near that of MHV and BCoV, where is the most variable region of this gene. The RNA secondary structure of SARS-CoV genomic packaging signal is very similar to that of MHV and BCoV. The same result was also obtained in studying the genomic packaging signals of PEDV and HCoV 229E. Further more, the genomic sequence multi-alignment indicated that the locations of packaging signals of SARS-CoV, PEDV, and HCoV overlaped each other. It seems that the mutation rate of packaging signal sequences is much higher than the N protein, while only subtle variations for the M protein. CONCLUSIONS: The probable genomic packaging signal of SARS-CoV is analogous to that of MHV and BCoV, with the corresponding secondary RNA structure locating at the similar region of ORF1b. The positions where genomic packaging signals exist have suffered rounds of mutations, which may influence the primary structures of the N and M proteins consequently. | QINLei XIONGBin LUOCheng GUOZong-Ming HAOPei SUJiong NANPeng FENGYing SHIYi-Xiang YUXiao-Jing LUOXiao-Min CHENKai-Xian SHENXu SHENJian-Hua ZOUJian-Ping ZHAOGuo-Ping SHITie-Liu HEWei-Zhong ZHONGYang JIANGHua-Liang LIYi-Xue | 2003 | Acta Pharmacologica Sinica2003,24,6: | 9 |
| 12 | Interferon-inducible cytoplasmic lncLrrc55-AS promotes antiviral innate responses by strengthening IRF3 phosphorylation显示文摘Type I interferon (IFN-I) production is efficiently induced to ensure a potent innate immune response to viral infection. How this response can be enhanced, however, remains to be explored. Here, we identify a new cytoplasmic long non-coding RNA (lncRNA), lncLrrc55-AS, that drives a positive feedback loop to promote interferon regulatory factor 3 (IRF3) signaling and IFN-I production. We show that lncLrrc55-AS is virus-induced in multiple cell types via the IFN-JAK-STAT pathway. LncLrrc55-AS-deficient mice display a weakened antiviral immune response and are more susceptible to viral challenge. Mechanistically, lncLrrc55-AS binds phosphatase methylesterase 1 (PME-1), and promotes the interaction between PME-1 and the phosphatase PP2A, an inhibitor of IRF3 signaling. LncLrrc55-AS supports PME-1-mediated demethylation and inactivation of PP2A, thereby enhancing IRF3 phosphorylation and signaling. Loss of PME-1 phenocopies lncLrrc55-AS deficiency, leading to diminished IRF3 phosphorylation and IFN-I production. We have identified an IFN-induced lncRNA as a positive regulator of IFN-I production, adding mechanistic insight into lncRNA-mediated regulation of signaling in innate immunity and inflammation. | Yumei Zhou Mengxuan Li Yiquan Xue Zhiqing Li Weitao Wen Xingguang Liu Yuanwu Ma Lianfeng Zhang Zhongyang Shen Xuetao Cao | 2019 | Cell Research2019,29,8: | 8 |
| 13 | Colony development and physiological characterization of the edible blue-green alga,Nostoc sphaeroides (Nostocaceae,Cyanophyta)显示文摘可食的蓝绿色的水藻, Nostoc sphaeroides K ü t 精力,能形成微殖民地和球形的宏殖民地。它被用作因为它的 nutraceutical 和药理学,草药的药和饮食的补充几个世纪有益于的一个有势力。然而,有限信息在球形的宏殖民地和影响他们的结构的环境因素的发展是可得到的。这份报告描述了 N 的形态发生。从单个毛状体的 sphaeroides 到宏殖民地。在这个过程期间,各种各样的尺寸的宏殖民地的很结构的特征是稠密的斑点,戒指,紧缩的核心和液体核心的形成;并且在宏殖民地以内的细丝显示出取决于宏殖民地的尺寸的不同长度和数组。同时,温度和轻紧张强烈也影响了宏殖民地的内部结构。同样微的殖民地进一步在尺寸增加了形成 30 个公里宏殖民地,区分进不同的外部、中间、内部的层的殖民地。外部层的细丝内部层比那些显示出更高最大的光合的率,更高轻的浸透点,和更高光合的效率;而内部层的细丝有叶绿素的一个更高的内容 and phycobiliproteins 比那些外部层。在这研究获得的结果为 N 的集体耕作是重要的。sphaeroides 作为一个 nutraceutical 产品。 | Zhongyang Deng Qiang Hu Fan Lu Guoxiang Liu Zhengyu Hu | 2008 | Progress in Natural Science:Materials International2008,18,12: | 7 |
| 14 | Malus-metasurface-assisted polarization multiplexing显示文摘Polarization optics plays a pivotal role in diffractive,refractive,and emerging flat optics,and has been widely employed in contemporary optical industries and daily life.Advanced polarization manipulation leads to robust control of the polarization direction of light.Nevertheless,polarization control has been studied largely independent of the phase or intensity of light.Here,we propose and experimentally validate a Malus-metasurface-assisted paradigm to enable simultaneous and independent control of the intensity and phase properties of light simply by polarization modulation.The orientation degeneracy of the classical Malus’s law implies a new degree of freedom and enables us to establish a one-to-many mapping strategy for designing anisotropic plasmonic nanostructures to engineer the Pancharatnam–Berry phase profile,while keeping the continuous intensity modulation unchanged.The proposed Malus metadevice can thus generate a near-field greyscale pattern,and project an independent far-field holographic image using an ultrathin and single-sized metasurface.This concept opens up distinct dimensions for conventional polarization optics,which allows one to merge the functionality of phase manipulation into an amplitudemanipulation-assisted optical component to form a multifunctional nano-optical device without increasing the complexity of the nanostructures.It can empower advanced applications in information multiplexing and encryption,anti-counterfeiting,dual-channel display for virtual/augmented reality,and many other related fields. | Liangui Deng Juan Deng Zhiqiang Guan Jin Tao Yang Chen Yan Yang Daxiao Zhang Jibo Tang Zhongyang Li Zile Li Shaohua Yu Guoxing Zheng Hongxing Xu Cheng-Wei Qiu Shuang Zhang | 2020 | Light(Science & Applications)2020,9,1: | 7 |
| 15 | LLDPE prepared by in situ polymerization using a dual-functional catalytic system of Ti(On-Bu)_4 /AlEt_3-Et(Ind)_2-ZrCl_2/MAO显示文摘Linear low-density polyethylene (LLDPE) was prepared by in situ polymerization using a dual-functional catalytic system containing Et(Ind)2ZrCl2/MAO and Ti(On-Bu)4 /AlEt3 used as co-polymerization catalyst and dimeriza-tion catalyst, respectively. The catalytic system showed high activity and the polymer with low melting point, narrow molecular weight distribution (MWD) and low crystallinity was produced. | LIU Zhongyang, XU Demin, GUO Cunyue, WANG Jun, HE Dawei & HU YouliangStale Key Lab of Engineering Plastics, Center for Molecular Science, Institute of Chemistry. Chinese Academy of Sciences, Beijing 100080, China Beijing Lab of Catalysis. China National Petroleum Corporation Key Lab of Catalysis, Beijing 100080, China | 2001 | Chinese Science Bulletin2001,46,24: | 7 |
| 16 | Genetic Types and Metallogenic Model for the Polymetallic Copper–Gold Deposits in the Tongling Ore District, Anhui Province, Eastern China显示文摘The Tongling ore district is one of the most economically important ore areas in the Middle–Lower Yangtze River Metallogenic Belt, eastern China. It contains hundreds of polymetallic copper–gold deposits and occurrences. Those deposits are mainly clustered(from west to east) within the Tongguanshan, Shizishan, Xinqiao, Fenghuangshan, and Shatanjiao orefields. Until recently, the majority of these deposits were thought to be skarn-or porphyry–skarn-type deposits; however there have been recent discoveries of numerous vein-type Au, Ag, and Pb-Zn deposits that do not fall into either of these categories. This indicates that there is some uncertainty over this classification. Here, we present the results of several systematic geological studies of representative deposits in the Tongling ore district. From investigation of the ore-controlling structures, lithology of the host rock, mineral assemblages, and the characteristics of the mineralization and alteration within these deposits, three genetic types of deposits(skarn-, porphyry-, and vein-type deposits) have been identified. The spatial and temporal relationships between the orebodies and Yanshanian intrusions combined with the sources of the ore-forming fluids and metals, as well as the geodynamic setting of this ore district, indicate that all three deposit types are genetically related each other and constitute a magmatic–hydrothermal system. This study outlines a model that relates the polymetallic copper–gold porphyry-, skarn-, and vein-type deposits within the Tongling ore district. This model provides a theoretical basis to guide exploration for deep-seated and concealed porphyry-type Cu(–Mo, –Au) deposits as well as shallow vein-type Au, Ag, and Pb–Zn deposits in this area and elsewhere. | FU Zhongyang XU Xiaochun HE Jun FAN Ziliang XIE Qiaoqin DU Jianguo CHEN Fang | 2019 | Acta Geologica Sinica(English Edition)2019,93,1: | 6 |
| 17 | Influence of torrefaction pretreatment on biomass gasification technology显示文摘Torrefaction is a slow pyrolysis process that is carried out in the relatively low temperature range of 220-300°C.The influence of torrefaction as a pretreatment on biomass gasification technology was investigated using a bench-scale torrefaction unit,a bench-scale laminar entrained-flow gasifier,and the analysis techniques TGA-FTIR and low temperature nitrogen adsorption.A series of experiments were performed to examine the characteristics of the torrefaction process,the properties of torrefaction products,and the effects of torrefaction on gas composition,cold gas efficiency and gasification efficiency.The results showed that during the torrefaction process the moisture content of biomass were reduced,and the wood fiber structure of the material was destroyed.This was beneficial to storage,transport and subsequent treatments of biomass in large scale.For solid products,torrefaction increased the energy density,decreased the oxygen/carbon ratio,and created a more complex pore structure.These improved the syngas quality and cold gas efficiency.Combustible gases accounted for about 50% of non-condensable gaseous torrefaction products.Effective use of the torrefaction gases can save energy and improve efficiency.Overall,biomass torrefaction technology has good application prospects in gasification processes. | CHEN Qing ZHOU JinSong LIU BingJun MEI QinFeng LUO ZhongYang | 2011 | Chinese Science Bulletin2011,56,14: | 6 |
| 18 | Targeted Double Negative Properties in Silver/Silica Random Metamaterials by Precise Control of Microstructures显示文摘Te mechanism of negative permittivity/permeability is still unclear in the random metamaterials,where the precise control of microstructure and electromagnetic properties is also a challenge due to its random characteristic.Here silver was introduced into porous SiO_(2) microsphere matrix by a self-assemble and template method to construct the random metamaterials.Te distribution of silver was restricted among the interstices of SiO_(2) microspheres,which lead to the precise regulation of electrical percolation(from hoping to Drude-type conductivity)with increasing silver content.Negative permittivity came from the plasma-like behavior of silver network,and its value and frequency dispersion were further adjusted by Lorentz-type dielectric response.During this process,the frequency of epsilon-near-zero(ENZ)could be adjusted accordingly.Negative permeability was well explained by the magnetic response of eddy current in silver micronetwork.Te calculation results indicated that negative permeability has a linear relation with ω^(0.5),showing a relaxation-type spectrum,diferent from the“magnetic plasma”of periodic metamaterials.Electromagnetic simulations demonstrated that negative permittivity materials and ENZ materials,with the advantage of enhanced absorption(40dB)and intelligent frequency selection even in a thin thickness(0.1 mm),could have potentials for electromagnetic attenuation and shielding.Tis work provides a clear physical image for the theoretical explanation of negative permittivity and negative permeability in random metamaterials,as well as a novel strategy to precisely control the microstructure of random metamaterials. | Peitao Xie Zidong Zhang Zhongyang Wang Kai Sun Runhua Fan | 2019 | Research2019,,1: | 6 |
| 19 | Study of the kinetic behaviour of biomass and coal during oxyfuel co-combustion显示文摘In this study,the thermogravimetric analysis(TGA)method has been used to evaluate the kinetic behavior of biomass,coal and its blends during oxyfuel co-combustion.The thermogravimetric results have been evaluated by the Coats-Redfern method and validated by Criado’s method.TG and DTG curves indicate that as the oxygen concentration increases the ignition and burn out temperatures approach a lower temperature region.The combustion characteristic index shows that biomass to coal blends of 28%and 40%respectively can achieve enhanced combustion up to 60%oxygen enrichment.In the devolatilization region,the activation energies for coal and blends reduce while in the char oxidation region,they increase with rise in oxygen concentration.Biomass,however,indicates slightly different combustion characteristic of being degraded in a single step and its activation energies increase with rise in oxygen concentration.It is demonstrated in this work that oxygen enrichment has more positive combustion effect on coal than biomass.At 20%oxygen enrichment,28%and 40%blends indicate activation energy of 132.8 and 125.5 kJ·mol^-1 respectively which are lower than coal at 148.1 kJ·mol^-1 but higher than biomass at 81.5 kJ·mol^-1 demonstrating synergistic effect of fuel blending.Also,at char combustion step,an increase in activation energy for 28%blend is found to be 0.36 kJ·mol^-1 per rise in oxygen concentration which is higher than in 40%blend at 0.28 kJ·mol^-1. | Oris Chansa Zhongyang Luo Chunjiang Yu | 2020 | Chinese Journal of Chemical Engineering2020,28,7: | 6 |
| 20 | Preparation of long-branched polyethylene by in situ poly-merization using late transition metal and metallocene catalysts显示文摘An in situ polymerization method was investigated to prepare long-branched polyethylene (LBPE) with ethylene alone and a single cocatalyst, methylalumoxane (MAO), by using a dual functional catalytic system containing late transition metal oligomerization catalyst and metal-locene copolymerization catalyst. The obtained long-branched polyethylene has the characteristics of low melting point, high activity and well-dispersed sequence distribution. | LIU Zhongyang GUO Cunyue MAZhi WANG Jun XU Demin HE Dawei HU Youliang | 2001 | Chinese Science Bulletin2001,46,24: | 5 |