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Meteorological Tower Observed CO_(2)Flux and Footprint in the Forest of Xiaoxing’an Mountains,Northeast China

Journal of Meteorological Research 2023年第1期37卷 126-140页

作者： Pengfei SUN Zhe QU chao yuan yuan yuan chao WANG Qingyu JIA Institute of Atmospheric Environment China Meteorological AdministrationShenyang 110166 Wuying National Climate Observatory Fenglin 153036 Yichun Meteorological Bureau Yichun 153000 College of Atmospheric Sciences Chengdu University of Information TechnologyChengdu 610225 Panjin Meteorological Bureau Panjin 124010 Heihe Meteorological Bureau Heihe 164300

The Xiaoxing’an Mountains,located in the temperate monsoon climate zone in Northeast China,have the largest and most complete virgin Korean pine forest in Asia,which has great potential for carbon *** on the observational data of the eddy-covariance system at Wuying National Climate Observatory in January 2015–November 2017,the CO_(2)flux in the forest ecosystem around the observatory was quantitatively studied and the distribution characteristics of the flux source area were analyzed by the Kljun model and the Agroscope Reckenholz–Tänikon footprint tool,providing references for assessing the carbon source/sink potential of the unique forest *** results showed that the annual total carbon flux around the observatory in 2015,2016,and 2017 was−756.84,−834.73,and−629.37 gC m−2,respectively,higher than that of other forest *** forest of the study area in the Xiaoxing’an Mountains was a strong carbon sink,with the strongest carbon fixation capacity in June and weakest in October,and the carbon flux of each month was less than *** flux source area under stable atmospheric conditions was larger than that under unstable conditions,and the source area was larger in the nongrowing season than in the growing *** size of the source area was largest in winter,followed by spring,autumn,and *** maximum length of the source area was 1614.12 m(5639.33 m)under unstable(stable)conditions when the flux contribution rate was 90%.The peak flux contribution was located near the sensor(i.e.,within 200 m)in all *** contribution of the source area from the coniferous and broadleaved mixed forest on the west side of the observatory was greater than(3.4 times)that from the Korean pine forest on the east side.

关键词： Xiaoxing’an Mountains forest ecosystem CO_(2)flux CO_(2)source/sink CO_(2)spectra carbon sequestration Kljun model footprint

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Improvement in Cr Nanoparticle Content in Ni-Cr Film by Co-deposition with Combined Surfactant HPB and CTAB

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Acta Metallurgica Sinica(English Letters) 2017年第10期30卷 999-1007页

作者： Li-Juan Qin yuan-chao Huang Laboratory for Corrosion and Protection Institute of Metal ResearchChinese Academy of Sciences College of Material Science and Engineering University of Science and Technology of China

The effects of single surfactant hexadecylpyridinium bromide（HPB） and cetyltrimethylammonium bromide（CTAB） and the combination of HPB and CTAB on the Cr nanoparticle content in the Ni-Cr film prepared by codeposition were investigated. Single HPB/CTAB addition inhibited the oxidation and amorphous transformation of the Cr nanoparticles in the plating bath and effectively stabilized the Cr nanoparticles content at approximately 10 mass% as a function of time. Moreover, the combination of HPB and CTAB formed a cylindrical micelle structure on the Cr nanoparticle surface, which prompted the formation of a layer of NiCr2O4. As a result, the Cr nanoparticle content increased sharply to 20 mass%.

关键词： Co-deposition Ni-Cr film Cr nanoparticle content HPB CTAB

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Reconstructing early transmission networks of SARS-CoV-2 using a genomic mutation model

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Zoological Research 2023年第3期44卷 494-504页

作者： chao-yuan Cheng Zhi-Bin Zhang State Key Laboratory of Integrated Management of Pest Insects and Rodents Institute of ZoologyChinese Academy of SciencesBeijing 100101China CAS Center for Excellence in Biotic Interactions University of Chinese Academy of SciencesBeijing 100049China

The coronavirus disease 2019(COVID-19)pandemic has greatly damaged human society,but the origins and early transmission patterns of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)pathogen remain ***,we reconstructed the transmission networks of SARS-CoV-2 during the first three and six months since its first report based on ancestor-offspring relationships using BANAL-52-referenced *** explored the position(i.e.,root,middle,or tip)of early detected samples in the evolutionary tree of *** total,6799 transmission chains and 1766 transmission networks were reconstructed,with chain lengths ranging from 1-9 *** root node samples of the 1766 transmission networks were from 58 countries or regions and showed no common ancestor,indicating the occurrence of many independent or parallel transmissions of SARS-CoV-2 when first detected(i.e.,all samples were located at the tip position of the evolutionary tree).No root node sample was found in any sample(n=31,all from the Chinese mainland)collected in the first 15 days from 24 December *** using six-month data or RaTG13-referenced mutation data were *** reconstruction method was verified using a simulation *** results suggest that SARS-CoV-2 may have already been spreading independently worldwide before the outbreak of COVID-19 in Wuhan,***,a comprehensive global survey of human and animal samples is essential to explore the origins of SARS-CoV-2 and its natural reservoirs and hosts.

关键词： SARS-CoV-2 Transmission chain Transmission network Ancestor-offspring relationship De novo mutation Back mutation Secondary mutation

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High Temperature Creep and Fracture Behavior of a Directionally Solidified Ni-base Superalloy

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Journal of Materials Science & Technology 1998年第3期14卷 219-225页

作者： yuan, chao Guo, Jianting Wang, Shuhe Yang, Hongcai Acad Sinica Inst Met Res Shenyang 110015 Peoples R China Northeastern Univ Dept Mat Sci & Engn Shenyang 110006 Peoples R China

The tensile creep-fracture properties of DZ17G, a directionally solidified superalloy, were investigated at 830-900 degree C. The results show that all of the creep curves exhibit negligible primary creep, relatively little steady-state creep and dominant tertiary creep stage. The higher apparent activation energy for creep (540 kJ/mol) suggests that the creep is controlled by Orowan bowing process. A large ratio of the fracture time to the onset time of tertiary creep is the consequence of microstructure change, i.e., gamma ' particles oriented coarsening parallel to the applied stress axis. The creep fracture data follow the Monkman-Grant relationship. The transgranular fracture mechanism proposed on the basis of the metallographic examinations is the linkage of the creep cracks which initiate at the discontinuities with the microstructure (such as the cast porosity, and the carbide/matrix interface) and also at the specimen surface, that propagate along the gamma / gamma ' interface with perpendicular to the applied stress axis, and the process of crack propagation can be described by the Tien model. (Edited author abstract) 31 Refs.

关键词： Nickel alloys

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Characteristics on Hydro-mechanical Transmission in Power Shift Process

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Chinese Journal of Mechanical Engineering 2009年第1期22卷 50-56页

作者： HU Jibin WEI chao yuan Shihua JING Chongbo National Key Laboratory of Vehicular Transmission Beijing Institute of Technology Beijing 100081 China

To improve the vehicular power and acceleration performance and reduce the shift impact, the study of the characteristics on power shift is necessary. Based on the flexible hydraulic unit of hydro-mechanical transmission, this paper explores the feasibility of shift without power interruption. With the four models concerning displacement ratio, rotational speed, rotational torque and power at ideal shift point, the characteristics on power shift in different running conditions are analyzed, and the rules of power shift are revealed. The theoretical analysis and test results show that the hydro-mechanical transmission can shift without power interruption in different running conditions. Furthermore, there exists an ideal shift point in theory, at which point the cycle power in hydro-mechanical transmission can＇t be generated, and the impact on the system can be reduced to the minimum. However, if before or after this ideal shift point, a cycle power can be generated.

关键词： stepless transmission hydro-mechanical transmission power shift

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A Numerical Investigation of Vortex-Induced Vibration Response and Fatigue Damage for Flexible Cylinders Under Combined Uniform and Oscillatory Flow

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China Ocean Engineering 2020年第4期34卷 488-499页

作者： yuan Yu-chao XUE Hong-xiang TANG Wen-yong State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Vortex-induced vibration(VIV)for flexible cylinders under combined uniform and oscillatory flow is a challenging and practical issue in ocean *** this paper,a time domain numerical model is adopted to investigate the characteristics of cross-flow VIV response and fatigue damage under different combined flow ***,the adopted VIV model and fatigue analysis procedure are validated well against the published experimental results of a4-m cylinder model under pure oscillatory ***,forty-five combined flow cases of the same cylinder model are designed to reveal the VIV response characteristics with different non-dimensional oscillation period T^*and combined ratio *** combined flow cases are classified into three categories to investigate the effect of r on cylinder’s dynamic response,and the effect of T*is described under long and short period ***,fatigue analysis is carried out to investigate how the structural fatigue damage varies with the variations of r and T^*.The captured characteristics of structural response and fatigue damage are explained through the VIV mechanism analysis.

关键词： vortex-induced vibration fatigue damage flexible cylinders combined flow

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Synthesis and Determination of Absolute Configuration of a Divergent Polyhydroxy Enyne Compound

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Chinese Chemical Letters 2005年第12期16卷 1569-1572页

作者： Zhi Jie XUE yuan chao LI Shanghai Institute of Materia Medica Chinese Academy of Sciences Shanghai 201203

Polyhydroxy enyne compound （＋）-（1＇S, 2R, 3S, 5S, 6S）-5,6-dimethoxy-5, 6-dimethyl- 2-（1＇-hydroxylpropyl-2-ne）-3-vinyl-l,4-dioxane has been synthesized from D-（-）-tartaric acid. A new chiral center was established by nucleophilic addition with 87% de. The modified Mosher＇s method was employed to confirm the absolute configuration of 17, which assigned the S-configuration at the new chiral center.

关键词： Tartaric acid enyne compound nucleophilic addition modified Mosher's method

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Geochemical speciation and spatial distributions of phosphorus in surface sediments from the basin of the Marcus-Wake seamounts in the western Pacific Ocean

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Acta Oceanologica Sinica 2022年第4期41卷 80-90页

作者： chao yuan Fansheng Meng Xuying Yao Jianyu Ni Key Laboratory of Submarine Geosciences Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China

The concentrations of five forms of phosphorus(P)including exchangeable or loosely adsorbed P(Ex-P),Febound P(Fe-P),authigenic P(Auth-P),detrital P(Det-P),and organic P(Org-P)from the basin among the Marcus-Wake seamounts(19.4°–24°N,156.5°–161.5°E)in the western Pacific Ocean were quantified using a sequential extraction method(SEDEX)to investigate the distribution and sources of different P *** of total P(TP)varied from 14.0μmol/g to 44.1μmol/g,with an average of(32.4±7.7)μmol/*** phosphorus,which was the major chemical form of sedimentary P,ranged from 12.6μmol/g to 40.6μmol/g,while the concentration of Org-P varied between 1.38μmol/g and 5.18μmol/g,accounting for 83.4%–93.4%and 6.6%–16.6%of the TP,*** relative proportions of the five P species followed the order of Det-P>Auth-P>Org-P>Fe-P>*** average,Det-P was the major P sink resulted from the atmospheric input and accounted for approximately 58.9%±12.4%of the ***-P and Org-P comprised 22.8%±11.4%and11.5%±3.0%of the TP,respectively,while Fe-P accounted for 5.1%±2.6%.Lastly,Ex-P comprised 1.6%±0.3%of the ***-P exhibited a negative correlation with Fe-P and Auth-P,while Fe-P showed a positive correlation with *** indicated that the formation of Fe-P and Auth-P was at the expense of the regeneration or remineralization of Org-P during early *** concentrations of Det-P and Auth-P as well as a low ratio of total organic C to reactive P(TOC/Rea-P)suggested that the aeolian input may play a significant role in sedimentary P budget in the study ***,well-oxygenated bottom water and low sedimentation rate could be responsible for the low TOC/Org-P ratio in the sediment.

关键词： phosphorus speciation SEDEX sediments western Pacific Ocean

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Numerical Forecasting of Icing on Structural Components of Offshore Platforms in Polar Regions

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China Ocean Engineering 2021年第4期35卷 588-597页

作者： BAI Xu SHEN Jie XUE Yan-zhuo SHU yuan-chao School of Naval Architecture&Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China College of Shipbuilding Engineering Harbin Engineering UniversityHarbin 150001China

The Polar Regions are rich in natural resources but experience an extremely cold *** surfaces of offshore platforms operating in the Polar Regions are prone to *** develop solutions to this problem of surface icing,the influence of both the liquid water concentration of the surrounding atmosphere and the average water droplet diameter on the formation of ice on two major structural components of offshore platforms was analyzed using a combination of Fluent and *** showed that at a wind speed of 7 m/s,as the concentration of liquid water in the air increases from 0.05 to 0.25 g/m3,the amount and thickness of the icing on the surfaces of the two structural components increase *** a wind speed of 7 m/s and when the size of the average water droplet diameter is 20–30(30–35)μm,as the average water droplet diameter increases,the amount and thickness of the icing on the surfaces of the two structural components increase(decrease)gradually.

关键词： offshore platform in cold regions icing numerical analysis icing thermodynamic model icing calculation process

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Activating supercooled electrolytes

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Materials Futures 2024年第4期3卷 192-194页

作者： yuan-chao Hu Liwei Jiang Songshan Lake Materials Laboratory DongguanPeople’s Republic of China The Chinese University of Hong Kong Hong Kong Special Administrative Region of ChinaPeople’s Republic of China

While materials science research in the rechargeable battery field is usually application-oriented,the general supercooled liquid theory from glass science can drive high-performance low-temperature aqueous batteries,... 详细信息

关键词： glass battery electrolytes supercooled liquids fragility

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