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Simulation of critical transitions and vulnerability assessment of Tibetan Plateau key ecosystems

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Journal of Mountain Science 2022年第3期19卷 673-688页

作者： YANG Fei MA Chao fang hua-jun State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources Research of Chinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China

Critical transitions in ecosystems may imply risks of unexpected collapse under climate changes,especially vegetation often responds sensitively to climate *** type of vegetation ecosystem states could present alternative stable states,and its type could signal the critical transitions at tipping points because of changed climate or other *** study analyzed the distribution of four key vegetation ecosystem types:desert,grassland,forest-steppe ecotone and forest,in Tibetan Plateau in China,using the latent class analysis method based on remote sensing data and climate *** study analyzed the impacts of three key climate factors,precipitation,temperature,and sunshine duration,on the vegetation states,and calculated the critical transition tipping point of potential changes in vegetation type in Tibetan Plateau with the logistic regression *** studied results showed that climatic factors greatly affect the vegetation states and vulnerability of the Tibetan *** comparison with temperature and sunshine duration,precipitation shows more obvious impact on differentiations of the vegetations status *** precipitation tipping point for desert and grassland transition is averagely 48.0 mm/month,70.7 mm/month for grassland and forest-steppe ecotone,and 115.0 mm/month for forest-steppe ecotone and *** temperature and sunshine duration only show different probability change between vegetation and non-vegetation type,but produce opposite *** Tibetan Plateau,the transition tipping points of vegetation and nonvegetation are about 12.1°C/month and 173.6 h/month for the temperature and sunshine duration,***,vulnerability maps calculated with the logistic regression results presented the distribution of vulnerability of Tibetan Plateau key *** vulnerability of the typical ecosystems in the Tibetan Plateau is low in the southeast and is high in the *** meteorological factors affect tree co

关键词： Vulnerability Transition Tipping point Tibetan Plateau Latent class analysis

Using ^(137)Cs Tracer Technique to Evaluate Erosion and Deposition of Black Soil in Northeast China

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Pedosphere 2006年第2期16卷 201-209页

作者： fang hua-jun YANG Xue-Ming ZHANG Xiao-Ping LIANG Ai-Zhen Northeast Institute of Geography and Agricultural Ecology CAS Changchun 130012 （China）. Graduate School of the Chinese Academy of Sciences Beijing 100039 （China） Greenhouse ＆ Processing Crops Research Centre Agriculture ＆ Agri-Food Canada Harrow Ontario NOR 1 GO （Canada）

Soil and water losses through erosion have been serious in the black soil region of Northeast China. Therefore, a sloping cultivated land in Songnen Plain was selected as a case study to： 1） determine the ^137Cs reference inventory in the study area; 2） calculate erosion and deposition rates of black soil on different slope locations; 3） conduct a sensitivity analysis of some model parameters; and 4） compare overall outputs using four different models. Three transects were set in the field with five slope locations for each transect, including summit, shoulder-slope, back-slope, foot-slope, and toe-slope. Field measurements and model simulation were used to estimate a bomb-derived ^137Cs reference inventory in the study area. Soil erosion and deposition rates were estimated using four ^137Cs models and percentage of ^137Cs loss/gain. The ^137Cs reference value in the study area was 2 232.8 Bq m^-2 with ^137Cs showing a clear topographic pattern, decreasing from the summit to shoulder-slope, then increasing again at the foot-slope and reaching a maximum at the toe-slope, Predicted soil redistribution rates for different slope locations varied. Among models, the Yang Model （YANG-M） overestimated erosion loss but underestimated deposition. However, the standard mass balance model （MBM1） gave predictions similar to a mass balance model incorporating soil movement by tillage （MBM2）. Sensitivity analysis of the proportion factor and distribution pattern of ^137Cs in the surface layer demonstrated the impact of ^137Cs enrichment on calculation of the soil erosion rate. Factors influencing the redistribution of fallout ^137Cs in landscape should be fully considered as calculating soil redistribution rate using ^137Cs technique.

关键词： black soil cesium-137 (^137Cs) Northeast China quantitative models soil erosion

Short-Term Impacts of No Tillage on Aggregate-Associated C in Black Soil of Northeast China

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Agricultural Sciences in China 2010年第1期9卷 93-100页

作者： LIANG Ai-zhen YANG Xue-ming ZHANG Xiao-ping SHEN Yan SHI Xiu-huan FAN Ru-qin fang hua-jun Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Changchun 130012 P.R.China Greenhouse ＆ Processing Crops Research Centre Agriculture ＆ Agri-Food Canada Ontario NOR 1G0 Canada Institute of Geographic Sciences and Natural Resources Research Centre Chinese Academy of Sciences Beijing 100101 P.R.China

In order to get a good indicator to evaluate the impacts of no tillage （NT） on soil structure and soil quality, we studied the dynamics of total soil organic carbon （SOC） and aggregate-associated SOC, and their relationships in the plow layer （30 cm） in black soil of Northeast China under NT practice. The tillage experiment was established in Dehui County, Jilin Province, China, in 2001. The total SOC and aggregate-associated SOC under 5-yr tillage treatments were measured. NT practices did not lead to the increase of average SOC content at 0-30 cm depth, but it did significantly increase SOC at the top soil （0-5 cm）. In NT plots, the change of SOC in 〉 1 000 μm aggregate was the same with that of total SOC, but the effect of NT on SOC in 〉 1 000 lain aggregate was greater than the effect on total SOC, suggesting that 〉 1 000 μm aggregate had more sensitive response to the impact of tillage practices. Also, significant positive correlation occurred between total SOC and SOC in 〉 1 000 μm aggregate in black soil. Consequently, in the short term soil macroaggregate 〉 1 000 μm could be used as an indicator to evaluate the impacts of tillage practices on soil structure in black soil of Northeast China.

关键词： no tillage soil organic carbon water-stable aggregate black soil

Quantitative characterizations of anisotropic dynamic properties in organic-rich shale with different kerogen content

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Petroleum Science 2024年第2期21卷 855-865页

作者： Jian-Yong Xie Yan-Ping fang Xing-hua Wu Jian'er Zhao jun-Cheng Dai jun-Xing Cao Ji-Xin Deng State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of TechnologyChengdu610059SichuanChina Key Lab of Earth Exploration&Information Techniques of Ministry of Education Geophysical InstituteChengdu University of TechnologyChengdu610059SichuanChina PetroChina Southwest Oil&Gasfield Company Chengdu610017SichuanChina

Understanding the quantitative responses of anisotropic dynamic properties in organic-rich shale with different kerogen content(KC)is of great significance in hydrocarbon exploration and *** controlled experiments with a single variable is challenging for natural shales due to their high variations in components,diagenesis conditions,or pore *** employed the hot-pressing technique to construct 11 well-controlled artificial shale with varying *** artificial shale samples were successive machined into prismatic shape for ultrasonic measurements along different *** revealed bedding perpendicular P-wave velocities are more sensitive to the increasing KC than bedding paralleling velocities due to the preferential alignments of *** elastic stiffnesses except C_(13)are generally decreasing with the increasing KC,the variation of C_(1) and C_(33)on kerogen content are more sensitive than those of C_(44)and C_(66).Apparent dynamic mechanical parameters(v and E)were found to have linear correlation with the true ones from complete anisotropic equations independent of KC,which hold value towards the interpretation of well logs consistently across formations,Anisotropic mechanical parameters(ΔE and brittlenessΔB)tend to decrease with the reducing KC,withΔB showing great sensitivity to KC *** the range of low KC(10%)shale,compilation of data from natural organic rich-shales globally verified the similar systematic relationships that can be empirically used to predict the fraction of KC in shales.

关键词： Elastic properties Organic shale Anisotropy Kerogen content Physical modeling

Safflower Yellow Inhibits Progression of Hepatocellular Carcinoma by Modulating Immunological Tolerance via FAK Pathway

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Chinese Journal of Integrative Medicine 2024年第4期30卷 339-347页

作者： JI hua-feng YANG Zi-qiang HAN jun-jun LI He-fang JIN Zhao-qing CHEN Wei-qing CHEN Fei-hua GONG Mou-chun Department of General Surgery First People's Hospital of Hangzhou Lin'an DistrictHangzhou(311300)China

Objective To explore the anti-tumor effect of safflower yellow(SY)against hepatocellular carcinoma(HCC)and the underlying potential *** An in vitro model was established by mixing Luc-Hepa1-6 cells and CD3^(+)CD8^(+)T cells,followed by adding programmed cell death protein 1(PD-1)antibody(Anti-mPD-1)with or without *** apoptosis was detected by flow cytometry and the level of inflammatory cytokines was determined by enzyme-linked immunosorbent *** protein levels of programmed cell death 1 ligand 1(PD-L1),chemokine ligand(CCL5),C-X-C motif chemokine ligand 10(CXCL10)were measured by Western *** in situ animal model was established in mice followed by treatment with anti-mPD-1 with or without *** imaging was monitored with an AniView 100 imaging *** establish the FAK-overexpressed Luc-Hepa1-6 cells,cells were transfected with adenovirus containing pcDNA3.1-FAK for 48 *** The fluorescence intensity,apoptotic rate,release of inflammatory cytokines,and CCL5/CXCL10 secretion were dramatically facilitated by anti-mPD-1(P<0.01),accompanied by an inactivation of PD-1/PD-L1 axis,which were extremely further enhanced by SY(P<0.05 or P<0.01).Increased fluorescence intensity,elevated percentage of CD3+CD8+T cells,facilitated release of inflammatory cytokines,inactivated PD-1/PD-L1 axis,and increased CCL5/CXCL10 secretion were observed in Anti-mPD-1 treated mice(P<0.01),which were markedly enhanced by SY(P<0.05 or P<0.01).Furthermore,the enhanced effects of SY on inhibiting tumor cell growth,facilitating apoptosis and inflammatory cytokine releasing,suppressing the PD-1/PD-L1 axis,and inducing the CCL5/CXCL10 secretion in Anti-mPD-1 treated mixture of Luc-Hepa1-6 cells and CD3+CD8+T cells were abolished by FAK overexpression(P<0.01).Conclusion SY inhibited the progression of HCC by mediating immunological tolerance through inhibiting FAK.

关键词： hepatocellular carcinoma safflower yellow Chinese medicine tumor microenvironment programmed cell death protein 1 focal adhesion kinase

Sequential enantioselective Ugi-4CR/post-Ugi transformation strategy:a precise construction of structurally diverse azaspiro polycyclic scaffolds

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Science China Chemistry 2024年第2期67卷 576-586页

作者： Xiao-Bao Wu jun-Xiu Shi Yi-Ming Ou hua-Jie Jiang Yi-jun fang Qi-Ming Wang Quan Gao Jie Yu Department of Applied Chemistry Anhui Province Engineering Laboratory for Green Pesticide Development and ApplicationAnhui Province Key Laboratory of Crop Integrated Pest ManagementAnhui Agricultural UniversityHefei230036China

A privileged strategy has been developed for the precise construction of enantioenriched azaspiro polycyclic *** diverse azaspiro polycycles bearing multiple contiguous stereocenters are obtained with excellent results(up to 99:1 e.r.,>95:5 d.r.) via sequential enantioselective four-component Ugi reactions/post-Ugi transformations with substrates containing prerequisite functional groups in the presence of anionic stereogenic-at-cobalt(Ⅲ) complexes.

关键词： asymmetric catalysis post-Ugi transformation anionic stereogenic-at-cobalt(Ⅲ)complex azaspiro polycyclic scaffold one-pot synthesis

Effects of retained dry material on the impact,overflow and landing dynamics

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3629-3640页

作者： jun fang Yifei Cui Haiming Liu State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijingChina Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong KongChina

During long-term operation,the performance of obstacles would be changed due to the material accumulating upslope the ***,the effects of retained material on impact,overflow and landing dynamics of granular flow have not yet been *** address this gap,physical flume tests and discrete element simulations are conducted considering a range of normalized deposition height h0/H from 0 to 1,where h0 and H represent the deposition height and obstacle height,*** analytical model is modified to evaluate the flow velocity and flow depth after interacting with the retained materials,which further serve to calculate the peak impact force on the ***,the computed impact forces successfully predict the experimental results when a≥25°.In addition,the results indicate that a higher h0/H leads to a lower dynamic impact force,a greater landing distance L,and a larger landing coefficient Cr,where Cr is the ratio of slope-parallel component of landing velocity to flow velocity just before *** to the existing overflow model,the measured landing distance L is underestimated by up to 30%,and therefore it is insufficient for obstacle design when there is retained ***,the recommended Cr in current design practice is found to be nonconservative for estimating the landing velocity of geophysical *** study provides insightful scientific basis for designing obstacles with deposition.

关键词： Granular flow Obstacle deposition Impact Overflow Landing

Structure and 2p decay mechanism of^(18)Mg

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Nuclear Science and Techniques 2024年第6期35卷 145-154页

作者： Long Zhou De-Qing fang Si-Min Wang Hui hua Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Shanghai Research Center for Theoretical Nuclear Physics NSFC and Fudan UniversityShanghai 200438China School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China

The recently discovered,extremely proton-rich nuclide 18 Mg exhibits ground-state decay via two sequential two-proton(2p)emissions through the intermediate nucleus,*** study investigates the structure and the initial 2p decay mechanism of^(18)Mgby examining the density and correlations of the valence protons using a three-body Gamow coupled-channel *** results show that the ground state of^(18)Mgis significantly influenced by the continuum,resulting in a significant s-wave ***,based on the current framework,this does not lead to a significant deviation in mirror symmetry in either the structure or spectroscopy of the 18Mg-18C ***,the time evolution analysis of the^(18)Mgground state suggests a simultaneous 2p emission during the first step of *** observed nucleon-nucleon correlations align with those of the light-mass 2p emitters,indicating a consistent decay behavior within this nuclear region.

关键词： Structure of^(18)Mg Two-proton decay Proton-proton correlation

Preparation of PVA/GO/h-BN Janus Film with High Thermal Conductivity and Excellent Flexibility via a Density Deposition Self-assembly Method

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Chinese Journal of Polymer Science 2024年第8期42卷 1217-1226页

作者： fang-hua Luo Zhi-Tao Dong Guo-hua Chen Chen Ma huai-Yuan Wang College of Chemistry and Chemical Engineering Northeast Petroleum UniversityDaqing 163318China College of Materials Science and Engineering Huaqiao UniversityXiamen 361000China School of Chemical Engineering and Technology and State Key Laboratory for Chemical Engineering Tianjin UniversityTianjin 300350China

Janus films with asymmetric physical/chemical properties have attracted con siderable attention due to their promising applications in personal thermal management,electronic skin s,sensors,actuators,***,traditional methods for fabricating Janus films conventionally need the assistance of an interface or auxiliary equipment,which are usually complex and ***,flexible poly(vinyl alcohol)(PVA)/graphene oxide(GO)/h-BN(recorded as PVA/GO/h-BN)Janus films with thermally,optically,and electrically anisotropic properties are fabricated by a simple density deposition self-assem bly method,which just utilizes the density difference between GO and h-BN during water *** results show that the two sides of the acquired Janus films have obvious asymmetric *** the original state of the PVA/GO/h-BN Janus films,the thermal conductivity of the GO side(10.06 W·m^(-1)·K^(-1))is generally lower than that of the h-BN side(10.48W·m^(-1)·K^(-1)).But after GO is reduced,the thermal conductivity of the rGO side reaches 12.17 W·m^(-1)·K^(-1),surpassing that of the h-BN *** addition,the relative reflectance of the h-BN side of Janus film is also significantly higher than that of the rGO side,and the su rface resistance difference between the two sides is about 4 orders of *** prepared PVA/GO/h-BN Janus films show great application potential in human thermal management,light conversion switches,and electronic *** study provides a simple and versatile strategy for fabricating Janus films with multifunctional(such as thermal,optical,and electrical)anisotropies.

关键词： Janus films PVA/GO/h-BN Density deposition self-assembly method