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Effects of calcium on the evolution of nitrogen during pyrolysis of a typical low rank coal

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International Journal of Coal Science & Technology 2020年第2期7卷 397-404页

作者： Xiongchao Lin Sasha Yang Xujun Chen Panpan Zheng yonggang wang Shu Zhang School of Chemical and Environmental Engineering China University of Mining and Technology(Beijing)Beijing100083China Department of New Energy Science and Technology Nanjing Forestry UniversityNanjing210037JiangsuChina

This study aims to investigate the effects of calcium on the migration of nitrogen in coal(coal-N)to N-containing gas species,particularly,NH3 and HCN(volatile-N)in volatiles,as well as the chemical transformation of the N in char during coal pyrolysis under different *** pyrolysis experiments of Shengli brown coal and its derived coal samples loaded with different contents of calcium were conducted under 600–800°C in a novel fluidized bed *** experimental results showed that during coal pyrolysis,the generation of NH3 is mainly derived from secondary reactions among volatiles,tar and char with the catalytic effect of mineral matter,especially calcium in *** pyrolysis temperature from 600 to 800°C could enhance the release of N in coal to ***,the increased pyrolysis temperature could also inhibit the generation of NH3 while facilitating the formation of *** release of HCN is more sensitive to pyrolysis ***,under higher pyrolysis temperatures,more N-containing structures in coal would become thermally unstable and crack into HCN;On the other hand,higher pyrolysis temperature could also enhance the decomposition of N in coal to N-containing species in tar or N2,thus reducing the release of HCN and *** in tar could either undergo secondary decomposition reactions,generating NH3,HCN,N2 and other N-containing species in gas phase,or experience condensation polymerization by forming macromolecular structure and be retained in char at high pyrolysis *** could significantly restrain the release of N from coal,thus reducing the yields of NH3 and *** coal pyrolysis,calcium catalytically enhances the fracture and combination of chemical bonds,generating abundant free *** free radicals could continuously attack N-containing structures and consequently release the N-containing gaseous products,such as NH3,HCN,N2 etc.,resulting in the decrease of N in ***

关键词： Brown coal Pyrolysis Nitrogen Calcium Transformation

A dendrite-free Li plating host towards high utilization of Li metal anode in Li–O_2 battery

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Science Bulletin 2019年第7期64卷 478-484页

作者： Chao Li Jishi Wei Panlong Li Wenfei Tang Wuliang Feng Jingyuan Liu yonggang wang Yongyao Xia Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Institute of New Energy iChEM (Collaborative Innovation Center of Chemistry for Energy Materials) Fudan University

The intense interest of Li–O_2 battery stems from its ultrahigh theoretical energy density, but its application is still hindered by the issues of Li anode. Herein, RuO_2-CNTs composite, a conventional O_2 cathode catalyst in Li–O_2 battery, is first utilized as an anode host for dendrite-free Li plating/stripping with high Coulombic efficiency. It is demonstrated that such excellent plating/stripping performance arises from the lithiophilicity characteristic of Ru nanoparticles(that is derived from the in-situ electrochemical conversion from RuO_2 to Ru/Li_2O) and buffer space provided by CNTs. Furthermore, the RuO_2-CNTs electrode pre-deposited with limited Li(RuO_2-CNTs@Li anode) is coupled with a RuO_2-CNTs catalytic cathode to form a Li–O_2 full cell, which displays an extended cycle life with dramatically improved energy *** achieved cell shows a high stability of 200 cycles with RuO_2-CNTs@Li anode(1 mg Li) that sheds light on the efficient utilization of Li anode in Li–O_2 batteries.

关键词： Li metal anode Li utilization Li-O2 battery Dendrite-free High energy density

Preparation and Properties of Guiqi Polysaccharides/Chitosan/Alginate Composite Hydrogel Microspheres

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Journal of Renewable Materials 2019年第12期7卷 1321-1332页

作者： Xiaoliang Zhao Yuting wang Xiuying Pu Jianzhong Ma Feifan Leng yonggang wang Yanling wang Shuhong Yang Fen Ran Weijie Zhang School of Life Science and Engineering Lanzhou University of TechnologyLanzhou730050China School of Material Science and Engineering Lanzhou University of TechnologyLanzhou730050China

A series of the Guiqi polysaccharides/chitosan/alginate composite hydrogel microspheres(GPcM)with different particle sizes were prepared with Guiqi polysaccharides(GP),chitosan(CS)and sodium alginate(Alg).The optimum preparation process was also determined by single factor and orthogonal experiment *** GPcM were characterized by fourier transform infrared spectroscopy(FT-IR),scanning electron microscope(SEM),drug loading efficiency test(LE),encapsulation efficiency test(EE)and in vitro release *** results showed that the Guiqi polysaccharides chitosan hydrogel(GPCH)and sodium alginate hydrogel(SAH)formed a crossover system in *** GPcM have a uniform particle size ranging from 395.1μm to 841.5μ*** drug loading efficiency and encapsulation efficiency of the GPcM were 56.3%and 72.6%,*** bovine serum albumin(BSA)loaded in the GPcM released slowly within 180 *** results suggested that the GPcM may have potential application value in drug sustained and controlled release system.

关键词： Guiqi polysaccharides composite hydrogel microspheres cross-linker drug loading

A harmonic analyzed parameterization of tide-induced mixing for ocean models

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Acta Oceanologica Sinica 2018年第7期37卷 1-7页

作者： WEI Zexun SUN Junchuan TENG Fei XU Tengfei wang yonggang XU Xiaoqing FANG Guohong The First Institute of Oceanography State Oceanic Administration Functional Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology

The tide-induced mixing plays an important role in the regulation of ocean *** simulation of continental shelf circulation is found to exhibit an unreasonable vertical thermohaline structure without consideration of tide *** this study,we establish a harmonic analyzed parameterization of tide-induced（HAT） mixing,by which means to derive time-depended function of mixing coefficient based on harmonic analysis of the vertical mixing *** employing HAT mixing parameterization scheme,a series of numerical experiments are conducted for the Yellow *** results show that an ocean circulation model with the HAT mixing involved is capable of reproducing the reasonable thermohaline structure of the Yellow Sea Cold Water Mass,similar to structures produced by explicit tidal forcing on the open *** advantage of the HAT method is its faster computation time,compared with models that directly resolve explicit tidal *** HAT parameterization for the tide-induced mixing has potential to improve both the accuracy and efficiency of ocean circulation and climate models.

关键词： tide-induced mixing harmonic analysis parameterization ocean circulation models Yellow Sea Cold Water Mass

Long baroclinic Rossby waves with periods of about 500 d near 20°N in the northwest Pacific Ocean

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Acta Oceanologica Sinica 2006年第3期25卷 1-10页

作者： CHEN Haiying QIAO Fangli FANG Guohong wang yonggang WEI Zexun Institute of Oceanography Chinese Academy of Sciences Qingdao 266071 China Key Laboratory of Marine Science and Numerical Modeling First Institute of Oceanography State Oceanic Administration Qingdao 266061 China Graduate School of Chinese Academy of Sciences Beijing 100039 China

On the basis of maps of sea level anomalies data set from October 1992 to January 2004, pronounced low frequency variations with periods of about 500 d are detected in the area near 20°N from 160°W to 130°E. A linear two-layer model is employed to explain the mechanism. It is found that the first-mode long baroclinic Rossby waves at 20°N in the northwest Pacific propagate westward in the form of free waves at a speed of about 10.3 cm/s. This confirms that the observed low frequency variabilities appear as baroclinic Rossby waves. It further shows that these low frequency variabilities around 20°N in the northwest Pacific can potentially be predicted with a lead up to 900 d.

关键词： low frequency oscillation Rossby waves maps of sea level anomalies northwest Pacific Ocean two-layer model

High-power passively Q-switched Nd:GdVO_4 laser with a reflective graphene oxide saturable absorber

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Chinese Optics Letters 2019年第2期17卷 41-45页

作者： Taijin wang Jiang wang yonggang wang Xiguang Yang Sicong Liu Ruidong Lü Zhendong Chen School of Physics and Information Technology Shaanxi Normal University

A single output Q-switched Nd:GdVO4 laser with a reflective graphene oxide(GO) saturable absorber was demonstrated. The shortest pulse duration in the Q-switched laser is 115 ns, and the output power ranges from1.23 W at 1.71 MHz to 2.11 W at 2.50 MHz when the pump power rises from 7.40 to 10.90 W with the utilization of GO Langmuir–Blodgett(LB) films based on the convenient and low-cost LB technique. To the best of our knowledge, it is the highest output power in a Q-switched laser with a GO saturable absorber.

关键词： High-power passively Q-switched

Hierarchical microstructures and strengthening mechanisms of nano-TiC reinforced CoCrFeMnNi high-entropy alloy composites prepared by laser powder bed fusion

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Journal of Materials Science & Technology 2023年第5期136卷 245-259页

作者： Hongyu Chen Konrad Kosiba Tiwen Lu Ning Yao Yang Liu yonggang wang Konda Gokuldoss Prashanth Challapalli Suryanarayana Key Laboratory of Impact and Safety Engineering of Ministry of Education of China Ningbo UniversityNingbo 315211China Leibniz Institute for Solid State and Materials Research Dresden Institute for Complex MaterialsHelmholtzstr.2001069 DresdenGermany Key Laboratory of Pressure Systems and Safety Ministry of EducationEast China University of Science and TechnologyShanghai 200237China Department of Mechanical and Industrial Engineering Tallinn University of Technology19086 TallinnEstonia Erich Schmid Institute of Materials Science Austrian Academy of SciencesA-8700 LeobenAustria CBCMT Vellore Institute of TechnologyVellore 632014Tamil NaduIndia Department of Mechanical and Aerospace Engineering University of Central FloridaOrlandoFL 32816-2450United States

High entropy alloys(HEAs)have recently received extensive attention due to their appealing mechani-cal performance given their simple phase *** study utilized laser powder bed fusion(LPBF)to fabricate high-performance HEA *** processing respective powder blends,LPBF enabled the fabrication of stronger composites with a uniformly distributed reinforcing ***,the impact of varying content of nano-scale TiC(1-3 wt%)particles for strengthening the CoCrFeMnNi HEA was *** microstructural features and mechanical properties of the HEA composites were investigated in *** introduction of nano-scale TiC into the HEA matrix encouraged the development of cross-scale hierarchical microstructure and eliminated the formation of oxide *** more nano-TiC led to a higher dislocation density and more refined microstructure in the HEA composites,whereas it posed little influence on the anisotropy of the HEA matrix which typically featured atexture along the building *** an optimized content of nano-TiC(1-2 wt%),the strength-ductility trade-offcan be overcome by exploiting multiple strengthening mechanisms encompassing grain boundary strengthening,solid solution strengthening,Orowan strengthening,and dislocation *** HEA composites showed a favored strength-ductility combination with a yield strength of 748-882 MPa,ultimate tensile strength of 931-1081 MPa,and fracture elongation of 23%-29%.This study demonstrates that the introduction of nano-scale TiC is an effective way to simultaneously improve the strength and ductility of additively manufactured HEA materials.

关键词： Additive manufacturing Laser powder bed fusion High entropy alloy Microstructure Mechanical property

Vertical displacement loading tides and self-attraction and loading tides in the Bohai, Yellow, and East China Seas

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Science China Earth Sciences 2013年第2期56卷 63-70页

作者： FANG GuoHong XU XiaoQing WEI ZeXun wang yonggang wang XinYi Key Laboratory of Marine Sciences and Numerical Modeling First Institute of Oceanography State Oceanic Administration

The loading tides are calculated by means of the Green's function method based on a high-resolution regional ocean tide model, the TOPO7.0 global ocean tide model, and the Gutenberg-Bullen A Earth model. The results show that the maximal amplitude of M2 vertical displacement loading (VDL) tide in the Bohai, Yellow, and East China Seas exceeding 28mm appears 150km off the Zhejiang coast; the second maximum exceeding 20mm appears in Inchon Bay; and the third maximum exceeding 14mm is located in the northeast of the North Yellow Sea. The maximal amplitudes of S2 VDL tide at the above three locations exceed 10, 8, and 4mm, respectively. The maximal amplitudes of the K1 and O1 VDL tides, exceeding 13 and 10 mm respectively, appear near the central and north Ryukyu Islands; the amplitudes tend to decease toward the inward areas. The phases of semidiurnal VDL tides are basically opposite to those of corresponding ocean tides. The phases of diurnal VDL tides are basically opposite to those of corresponding ocean tides in the most part of the East China Sea and the eastern part of the South Yellow Sea. This anti-phase relationship generally does not hold in the rest parts of the Bohai and Yellow Seas. The distribution patterns of self-attraction and loading (SAL) tides are very similar to those of VDL tides. The SAL tides have amplitudes about 1.2-1.7 times of the corresponding VDL tides and their phases are basically opposite to the corresponding VDL tides. The maximal amplitude of M2 SAL tide also appears off the Zhejiang coast, with a magnitude exceeding 42mm.

关键词： Bohai Sea Yellow Sea East China Sea ocean tides loading tides self-attraction and loading tides

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Synergistic Effects of Salt Concentration and Working Temperature towards Dendrite-Free Lithium Deposition

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Research 2019年第1期2019卷 391-399页

作者： Panlong Li Chao Li Yang Yang Chanyuan Zhang Renhe wang Yao Liu yonggang wang Jiayan Luo Xiaoli Dong Yongyao Xia Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Institute of New EnergyFudan UniversityShanghai 200433China State Key Laboratory of Chemistry Engineering School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

The lithium-(Li-)metal anode is crucial for developing high-energy-density batteries,while its dendritic growth and the low charge/discharge Coulombic efficiency in organic electrolytes hinder its practical ***,we employed an in situ optical microscope to investigate the effect of the electrolyte concentration and the working temperature on the Li-plating/-stripping *** is found that a higher concentration electrolyte can suppress its side reaction to improve the charge/discharge Coulombic efficiency,and a higher temperature can help lithium plate/strip uniformly with less lithium dendritic *** average Coulombic efficiency was obtained as high as 99.2%for over 150 cycles with a fixed plating capacity of 2 mAh cm^(-2) on copper foil in a 3 mol/kg ether-based electrolyte under 60℃,which provides an efficient and facile strategy for developing high-performance Li-metal batteries.

关键词： electrolyte lithium stripping