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银川市生态系统服务价值评估及多情景模拟

水土保持研究 2025年第1期32卷 294-304页

作者：解铭威周慧荻陈耸王向荣北京林业大学园林学院

[目的]土地利用变化影响生态系统服务价值（ESV）,研究多情景下土地利用变化并评估ESV,对优化土地管理和维护生态安全具有重要意义。[方法]设置4种情景，通过多目标规划（MOP）求取不同目标下土地利用结构最优解，借助PLUS模型预测2030... 详细信息

[目的]土地利用变化影响生态系统服务价值（ESV）,研究多情景下土地利用变化并评估ESV,对优化土地管理和维护生态安全具有重要意义。[方法]设置4种情景，通过多目标规划（MOP）求取不同目标下土地利用结构最优解，借助PLUS模型预测2030年土地利用空间分布情况，采用当量因子法评估ESV,并使用空间自相关分析集聚特征、Pearson相关性探究权衡协同关系。[结果]（1） 2000—2020年，银川市土地利用类型以耕地和草地为主，建设用地扩张473.1 km2,耕地与草地减少。（2）自然演变和经济优先情景建设用地增加，草地减少；生态优先情景林地、草地增加，耕地减少363.9 km2;可持续发展情景耕地几乎不变，林地、水域增加。（3） ESV呈下降趋势，4种情景总体ESV分别为47.184,45.404,53.924,49.711亿元，水文调节和气候调节占主导地位。（4） 11项ESV间存在广泛而显著的协同关系，食物生产与其他服务的协同性较低。[结论]可持续发展情景扭转ESV的下降趋势并取得较高经济效益，为规划提供依据，未来应加强对林地与水域的保护，有利于提高ESV。

关键词：土地利用生态系统服务 PLUS模型多目标规划当量因子

A quasi-one-dimensional model for hypersonic reactive flow along the stagnation streamline

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Chinese Journal of Aeronautics 2016年第6期29卷 1517-1526页

作者： chen song Sun Quanhua State Key Laboratory of High Temperature Gas Dynamics Institute of Mechanics Chinese Academy of Sciences School of Engineering Science University of Chinese Academy of Sciences

This study proposes a quasi-one-dimensional model to predict the chemical nonequilibrium flow along the stagnation streamline of hypersonic flow past a blunt body. The model solves reduced equations along the stagnation streamline and predicts nearly identical results as the numerical solution of the full-field Navier-Stokes equations. The high efficiency of this model makes it useful to investigate the overall quantitative behavior of related physical-chemical phenomena. In this paper two important properties of hypersonic flow, shock stand-off distance and oxygen dissociation, are studied using the quasi-one-dimensional model with the ideal dissociating gas model. It is found that the shock stand-off distance is affected by both chemical and thermal *** shock stand-off distance will increase when the flow conditions are changed from equilibrium to non-equilibrium, because the average density of the shock-compressed gas will decrease as a result of the increase in translational energy. For oxygen dissociation, the maximum value of its dissociation degree along the stagnation line varies with the flight altitude. It is increased at first and decreased thereafter with the altitude, which is due to the combination effect of the equilibrium shift and chemical non-equilibrium relaxation. The overall variation of the maximum dissociation is then plotted in the speed and altitude coordinates as a reference for engineering application.

关键词： Quasi-one-dimensional model Hypersonic Non-equilibrium Stagnation flow Shock stand-off distance

Synthesis of Fe_3O_4 nanoparticles by wet milling iron powder in a planetary ball mill

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China Particuology 2007年第5期5卷 357-358页

作者： Ding chen song Ni Zhenhua chen Institute for Materials Research Hunan University Changsha 410082 China

Fe3O4 nanoparticles with sizes ranging from 30 to 80 nm were synthesized by wet milling iron powders in a planetary ball mill. The phase composition and the morphologies of the as-synthesized products were measured by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. Nanosized Fe3O4 particles were prepared by wet milling metallic iron powder （-200 mesh, 99%） in a planetary ball mill equipped with stainless steel vials using iron balls under distilled water with a ball-to-powder mass ratio of 50：1 and at a rotation speed of 300 rpm. The use of the iron balls in this method played a key role in Fe3O4 formation. The present technique is simple and the process is easy to carry out.

关键词： Fe3O4 Wet milling Planetary ball mill

Influence of sintering temperature on the phases and photoelectric characteristics of BiOCl/ZnO composite powders

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International Journal of Minerals,Metallurgy and Materials 2017年第12期24卷 1438-1447页

作者： song chen De-gui Zhu School of Materials Science and Engineering Southwest Jiaotong UniversityChengdu 610031China

Zinc oxide is a typical functional oxide that has been widely researched for various industry applications due to its peculiar physical characteristics. However, to achieve its potential in promising applications, much work has been diligently performed to improve the physical properties of ZnO. In this work, an aqueous suspension route was used to prepare BiOCl/ZnO composite powders, and sintering processes were applied to investigate the influence of sintering temperature on the phase evolutions, microstructures, and photoelectric characteristics of BiOCl/ZnO composite powders. The results indicated that the photoelectric properties mainly depend on the relevant content of BiOCl in the composite powders and the sintering temperature. The photoelectric measurements in K_2SO_4 solutions show that the photoelectric properties of the samples with the appropriate BiOCl content(0.3 mol% and 2.0 mol%) are better than those of ZnO and commercial TiO_2(P_(25)) powders, but the photoelectric measurements in NaOH solutions indicate that the photoelectric characteristics of the as-sintered samples are only better than those of P_(25).

关键词： ZnO/BiOCl composites sintering temperature microstructures photoelectric characteristics

Low-temperature densification sintering and properties of CaAl_2Si_2O_8 ceramics with MeO·2B_2O_3(Me=Ca,Sr,Ba)

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International Journal of Minerals,Metallurgy and Materials 2015年第9期22卷 977-986页

作者： song chen De-gui Zhu School of Materials Science and Engineering Southwest Jiaotong University

Dense CaAl2Si2O8 ceramics were prepared via a two-step sintering process at temperatures below 1000℃. First, pre-sintered CaAl2Si2O8 powders containing small amounts of other crystal phases were obtained by sintering a mixture of calcium hydroxide and kaolin powders at 950℃ for 6 h. Subsequently, the combination of the pre-sintered ceramic powders with MeO＇2B203 （Me = Ca, Sr, Ba） flux agents enabled the low-temperature densification sintering of the CaAl2Si2O8 ceramics at 950℃. The sintering behavior and phase formation of the CaAl2Si2O8 ceramics were investigated in terms of the addition of the three MeO·2B2O3 flux agents. Furthermore, alumina and quartz were introduced into the three flux agents to investigate the sintering behaviors, phase evolvements, microstructures, and physical properties of the resulting CaA12Si208 ceramics. The results showed that, because of their low-melting characteristics, the MeO·2B2O3 （Me = Ca, Sr, Ba） flux agents facilitated the formation of the CaAl2Si2O8 ceramics with a dense microstructure via liquid-phase sintering. The addition of alumina and quartz to the flux agents also strongly affected the microstructures, phase formation, and physical properties of the CaA12Si208 ceramics.

关键词： ceramics densification sintering materials properties anorthite borates alumina quartz

A new resource-rich carbonate luminescent host KNa_(5)Ca_(5)(CO_(3))_(8):A case study activated by Eu^(3+) for red-phosphor purpose

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Journal of Rare Earths 2021年第8期39卷 913-920页

作者： Yunjian Wang song chen Lei Geng College of Chemistry and Materials Science Huaibei Normal UniversityHuaibei 235000China College of Physics and Engineering Qufu Normal UniversityQufu 273100China

Exploring and designing new luminescent host with rich resource is beneficial to reducing the cost and the large-scale application of luminescent ***,a series of novel Eu^(3+)-activated KNa5-Ca5(CO3)8 red-emitting phosphors with different Eu^(3+) concentrations were successfully synthesized under mild hydrothermal *** and SEM characterizations show that all as-prepared KNa_(5)Ca_(5)(CO_(3))_(8):Eu^(3+) samples crystallize in a hexagonal structure,P63 mc(No.186) space group,and show monodispersed hexagonal sheet mo rphologies,within a side length interval about of 2-3μm and a thickness of about 0.6 μm,Eu^(3+) doping within 6 mol% concentration has little influence on the crystal structure of the host,as indicated by XRD,and FT-IR results,but thermal stability changes as shown by the ***_(5)Ca_(5)(CO_(3))_(8) phosphors with different Eu^(3+) concentrations can emit red-light under effectively excitation by near-UV *** chromaticity coo rdinates of all KNa_(5)Ca_(5)(CO_(3))_(8):Eu^(3+) phosphors were calculated to locate in red region,and CCT of each sample is the range from 2815 to 3650 K,very close to the tungsten lamp ***,concentration quenching phenomenon appearing at 5 mol% is found to be the result of electric multipolar interaction of Eu^(3+)activators,and the decay lifetime is about1.63 ms,which almost unchanges with Eu^(3+) doping ***,thermal quenching analysis reveals good thermal stability with thermal activation energy of about 0.216 *** results reported here demonstrate that KNa_(5)Ca_(5)(CO_(3))_(8) is a promising fluorescent host for LEDs applications.

关键词： Carbonates KNa_(5)Ca_(5)(CO_(3))_(8) Hydrothermal synthesis Eu^(3+)doping Photoluminescence Rare earths

Controlling Quantum State Transfer in Spin Chain with Confined Field

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Communications in Theoretical Physics 2006年第4X期46卷 749-754页

作者： chen Bing song Zhi Department of Physics Nankai University Tianjin 300071 China

As a demonstration of the spectrum-parity matching condition （SPMC） for quantum state transfer, we investigate the propagation of single-magnon state in the Heisenberg chain in the confined external tangent magnetic field analytically and numerically. It shows that the initial Gaussian wave packet can be retrieved at the counterpart location near-perfectly over a longer distance if the dispersion relation of the system meets the SPMC approximately.

关键词： quantum state transfer spin chain confined field

Investigation on martensitic steel using a quenching-partitioning-tempering process via electron backscatter diffraction analysis

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Science China(Technological Sciences) 2012年第3期55卷 646-651页

作者： chen song YU Hao School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China

A new quenching-partitioning-tempering （Q-P-T） process was designed based on the recently developed quenching and partitioning （＆ P） treatment by Speer et al. The orientation relationships （ORs） of martensite （α） in Q-P-T steel tempered under different conditions were investigated using a scanning electron microscope with an electron backscatter diffraction unit. The morphology and crystallography of lath martensite within a packet were analyzed. Martensites exhibiting an initial austenite （y） grain in the orientation image map of different samples were chosen and their { 111 }α pole figures were drawn. The pole figures were fitted according to the ideal Kurdjumov-Sachs （K-S） and Nishiyama-Wasserman （N-W） ORs, which were calculated using Matlab and with a y crystal-oriented （001）γ[100]γ as the reference frame. The martensite OR in the Q-P-T steel follows both the K-S and N-W ORs; however, the K-S OR is predominant. This characteristic does not change in the samples further tempered at different temperatures.

关键词： quenching-partitioning-tempering process EBSD orientation relationship tempering

A NON-OSCILLATORY KINETIC SCHEME FOR MULTI-COMPONENT FLOWS WITH THE EQUATION OF STATE FOR A STIFFENED GAS

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Journal of Computational Mathematics 2011年第6期29卷 661-683页

作者： Yibing chen song Jiang Institute of Applied Physics and Computational Mathematics P.O. Box 8009 Beijing 100088 China

We extend the traditional kinetic scheme for ideal gases to the Euler equations with the equation of state for a multi-component stiffened gas. Based on a careful analysis of the oscillation mechanism of the traditional kinetic scheme across contact discontinuities, we propose a new non-oscillatory kinetic （NOK） scheme for multi-component stiffened gases. The basic idea in the construction is to use a flux splitting technique to construct numerical fluxes which do not depend on the concrete form of the equilibrium state. The new scheme can not only can avoid spurious oscillations of the pressure and velocity near a material interface which are observed in the traditional kinetic schemes such as the kinetic flux vector splitting （KFVS） and BGK schemes, but also can deal with the stiffened gas equation of state. Moreover, we also carry out a careful analysis on the consistency condition, truncation error and positivity of the NOK scheme. A number of 1D and 2D numerical tests are presented which demonstrate the accuracy and robustness of the new scheme in the simulation of problems with smooth, weak and strong shock wave regions.

关键词： Kinetic scheme Non-oscillation Multi-component Stiffened gases.