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A new monitoring index for ecological vulnerability and its application in the Yellow River Basin,china from 2000 to 2022

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Journal of Arid Land 2024年第9期16卷 1163-1182页

作者： GUO Bing XU mei zhang Rui LUO Wei school of Civil Engineering and Geomatics Shandong University of TechnologyZibo 255000China Key Laboratory of Remote Sensing of Gansu Province Heihe Remote Sensing Experimental Research StationNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China North china Institute of Aerospace Engineering Langfang 065000China

The ecological environment of the Yellow River Basin has become more fragile under the combined action of natural and manmade ***,the change mechanisms of ecological vulnerability in different sub-regions and periods vary,and the reasons for this variability are yet to be ***,in this study,we proposed a new remote sensing ecological vulnerability index by considering moisture,heat,greenness,dryness,land degradation,and social economy indicators and then analyzed and disclosed the spatial and temporal change patterns of ecological vulnerability of the Yellow River Basin,china from 2000 to 2022 and its driving *** results showed that the newly proposed remote sensing ecological vulnerability index had a high accuracy,at 86.3.%,which indicated a higher applicability in the Yellow River *** 2000 to 2022,the average remote sensing ecological vulnerability index of the Yellow River Basin was 1.03.denoting moderate vulnerability *** intensive vulnerability area was the most widely distributed,which was mostly located in the northern part of Shaanxi Province and the eastern part of Shanxi *** 2000 to 2022,the ecological vulnerability in the Yellow showed an overall stable trend,while that of the central and eastern regions showed an obvious trend of *** gravity center of ecological vulnerability migrated southwest,indicating that the aggravation of ecological vulnerability in the southwestern regions was more severe than in the northeastern regions of the *** dominant single factor of changes in ecological vulnerability shifted from normalized difference vegetation index(NDVI)to temperature from 2000 to 2022,and the interaction factors shifted from temperature∩NDVI to temperature∩precipitation,which indicated that the global climate change exerted a more significant impact on regional *** above results could provide decision support for the ecological protection and restoration of the Y

关键词： ecological vulnerability spatio-temporal pattern gravity center migration trajectory interaction factors geodetector green index q-value

Facile synthesis of composite polyferric magnesium-silicate-sulfate coagulant with enhanced performance in water and wastewater

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 574-584页

作者： Xiangtao Huo Rongxia Chai Lizheng Gou mei zhang Min Guo school of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

The coagulation process is a widely applied technology in water and wastewater *** composite polyferric mag-nesium-silicate-sulfate(PFMS)coagulants were synthesized using Na_(2)SiO_(3.·9H_(2)O,Fe_(2)(SO_(4))_(3.,and MgSO_(4) as raw materials in this *** effects of aging time,Fe:Si:Mg,and OH:M molar ratios(M represents the metal ions)on the coagulation performance of the as-pre-pared PFMS were systematically investigated to obtain optimum *** results showed that PFMS coagulant exhibited good co-agulation properties in the treatment of simulated humic acid-kaolin surface water and reactive dye *** the molar ratio was controlled at Fe:Si:Mg=2:2:1 and OH:M=0.3.,the obtained PFMS presented excellent stability and a high coagulation *** removal efficiency of ultraviolet UV254 was 99.81%,and the residual turbidity of the surface water reached 0.56 NTU at a dosage of 3. mg·L^(-1).After standing the coagulant for 120 d in the laboratory,the removal efficiency of UV254 and residual turbidity of the surface wa-ter were 88.12%and 0.68 NTU,respectively,which accord with the surface water treatment *** addition,the coagulation performance in the treatment of reactive dye wastewater was greatly improved by combining the advantages of magnesium and iron *** with polyferric silicate-sulfate(PFS)and polymagnesium silicate-sulfate(PMS),the PFMS coagulant played a better decolor-ization role within the pH range of 7-13.

关键词： polyferric-magnesium-silicate-sulfate composite coagulants water and wastewater excellent stability high coagulation ef-ficiency decolorization

South china's Gondwana connection in the Paleozoic:Paleomagnetic evidence

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Progress in Natural Science:Materials International 2004年第1期14卷 86-91页

作者： zhang Shihong*(school of Earth sciences and Resources,{3. university of Geosciences, beijing 100083.{3.) china Univ Geosci Sch Earth Sci & Resources Beijing 100083 Peoples R China

The reconstruction in which the South china Block (SCB) lies along the Great India Australia region of Gondwana margin is tested by using existing Paleozoic paleomagnetic data. Under the proposed reconstruction, all six high quality paleopoles from the SCB between the Early Cambrian and late Early Devonian (～400 Ma) are in good agreement with coeval paleopoles from Gondwana. Thereafter, the apparent polar wander paths for the SCB and Gondwana diverge markedly. This indicates that the SCB had been part of Gondwana and the connection was intact from at least Early Cambrian until late Early Devonian, but they began to separate by late Middle Devonian (～3.5 Ma).

关键词： South china block Gondwana paleomagnetism reconstruction

Production of O' -sialon-SiC Composites by Carbon Reduction-Nitridation

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International Journal of Minerals,Metallurgy and Materials 1998年第1期12卷 26-30页

作者： Haijun zhang Wenchao Li Xiangcong Zhong (Applied Science school, university of Science and Technology {3., {3. 1 0008 3. china) Applied Science school University of Science and Technology Beijing Beijing 100083 China

The effect of temperature, soak times, carbon and addition on composites was discussed in the process ofsynthesizing O'-sialon-SiC by carbonthermal reduction-nitration from nature kaolin. It showed that the fracturestrength (MOR) of composites sintered under certain conditions can be up to 140MPa at room temperature. Thetarget parameter optima regions with good mechanical properties of this material were also indicated by usingcomputer pattern recognition program.

关键词： O'-sialon-SiC compostites carbonthermal reduction-nitration pattern recognition program

Calculation Models of Mass Action Concentrations for Metallic Melts Involving Monotectic

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Journal of university of Science and Technology beijing 2001年第4期8卷 248-253页

作者： Jian zhang Metallurgy school, university of Science and Technology {3., {3. 100083. china Univ Sci & Technol beijing Met Sch Beijing 100083 Peoples R China

Based on the phase diagrams, measured activities as well asDeltaG(m) and DeltaG(xs), calculating models of mass action concentrations for metallic melts involving monotectic have been formulated. The calculated results agree with practice on the whole, showing that the models deduced generally can reflect the structural characteristics of these melts. The metastable compounds formed in the melts are of the types A(2)B(3., AB(2), A(2)B(3. or AB and A(2)B(3.+AB etc..

关键词： metallic melts monotectic activity mass action concentration

Cleaning of Chromate Manufacture Process

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International Journal of Minerals,Metallurgy and Materials 2000年第2期14卷 132-134页

作者： Xing Zou Yi zhang(Applied Science school, university of Science and Technology {3., {3. 100083. china)(Institute of Engineering Chemistry and Metallurgy, Chinese Academy of sciences, {3. 100080, china) Applied Science school University of Science and Technology Beijing Beijing 100083 China Institute of Engineering Chemistry and Metallurgy Chinese Academy of Sciences Beijing 100080 China

Sodium chromate solubility is determined in the range of NaOH concentrations from 450 to 810 g/L andsolution temperatUres from 3. to 110℃. The optimized conditions to separate sodium chromate from NaOH inleached solution are resolved. It is first found the method to efficiently separate sbdium chromate from NaOH andsodium altuninate in crude sodium chromate. Bench-scale studies on the separating are performed. Finally, goodseparation results are achieved.

关键词： chromate separation clean process

Moderate deviation for super-Brownian motion with immigration

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Science china Mathematics 2004年第3期47卷 440-452页

作者： zhang mei Department of Mathematics, beijing Normal {3., beijing 100875, china Department of Mathematics, The Central {3. of Finance and Economics, beijing 100081, china 1. Department of Mathematics Beijing Normal University 100875 Beijing China 2. Department of Mathematics The Central University of Finance and Economics 100081 Beijing China

We prove a moderate deviation principle for a super-Brownian motion with immigration of all dimensions, and consequently fill the gap between the central limit theorem and large deviation principle.

关键词： moderate deviation principle super-Brownian motion with immigration large deviation principle evolution equation

On the local wellposedness of 3.D water wave problem with vorticity

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Science china Mathematics 2007年第8期50卷 1065-1077页

作者： Ping zhang~1 Zhi-fei zhang~2 1 Academy of Mathematics and Systems Science,Chinese Academy of sciences,{3. 100080,china 2 school of mathematical sciences,Peking university,{3. 100871,china Academy of Mathematics Systems Science Chinese Academy of Sciences Beijing 100080 China school of mathematical sciences Peking University Beijing 100871 China

In this article, we first present an equivalent formulation of the free boundary problem to 3.D incompressible Euler equations, then we announce our local wellposedness result concerning the free boundary problem in Sobolev space provided that there is no self-intersection point on the initial surface and under the stability assumption that $\frac{{\partial p}}{{\partial n}}(\xi )\left| {_{t = 0} } \right. \leqslant - 2c_0 < 0$ being restricted to the initial surface.

关键词： water-waves free boundary incompressible Euler equations primary 3.Q3. 76B03 secondary 3.J67 3.L80

Algorithm for Computation of Unstructured Real Stability Radius and Its Applications

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International Journal of Minerals,Metallurgy and Materials 1998年第4期12卷 245-250页

作者： Xiaodan zhang Lequan Min(Applied Science school, university of Science and Technology {3., {3. 100083. china) Applied Science school University of Science and Technology Beijing Beijing 100083 China

An algorithm for the computation of the unstructured real stability radius of high dimensional linearsystem is presented. Using the accurate formula of the real stability radius of 2-dimensional system linear systemchecks the algorithm. The result shows that the algorithm is reliable and efficient. As applications, the unstructuredreal stability radii of 2-dimensional Chua's circuit and 3.dimensional piecewise-linear system are calculated, thedynamical orbits of the corresponding perturbed systems are simulated.

关键词： lincar systems stability robustness parameter perturbation computational methods