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Synthesis and structural characterization of Zn_3N_2.powder

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Science China(Physics,Mechanics & Astronomy) 2005年第2期48卷 201-210页

作者： ZONG Fujian1, MA Honglei1, XUE Chengshan2. ZHUANG Huizhao2. ZHANG Xijian1, MA Jin1, JI Feng1 & XIAO Hongdi1 1. School of Physics and Microelectronics, shandong university, Jinan 2.0100, China 2. {2. of Semiconductor, shandong Normal university, Jinan 2.0014, China School of Physics and Microelectronics Shandong University Jinan 250100 China institute of Semiconductor Shandong Normal University Jinan 250014 China

Zinc nitride (Zn3N2. powder has been synthesized through the nitridation reaction of Zn powder with NH3 gas (at the flow rate of 500 ml/min) at the nitridation temperature of 600℃ for 12. min. X-ray diffraction (XRD) indicates that Zn3N2.is cubic in structure with the lattice constant being a = 0.9788 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that Zn3N2.powder has surface morphology of various types. X-ray photoelectron spectroscopy (XPS) shows the differences in chemical bonding states between Zn3N2.and ZnO, and confirms the formation of N–Zn bonds. Observation through high resolution transmission electron microscopy (HRTEM) also indicates that the computer simulation of the structure of Zn3N2.is consistent with the structural model put forward by Partin.

关键词： nitridation, Zn3N2 powder, structure, XRD, SEM, TEM, HRTEM, XPS.

Recurrence spectra of He atoms in strong external fields

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Science China(Physics,Mechanics & Astronomy) 2004年第4期47卷 477-484页

作者： LIN Shenglu1, LI Hongyun1, WANG Dehua2. ZHAO Wenli1 & GAO Feng1 1. Department of Physics, shandong Normal university, Jinan 2.0014, China 2. Department of Mathematics and Physics, shandong institute of Architecture and Engineering, Jinan 2.0014, China 1. Department of Physics Shandong Normal University 250014 Jinan China 2. Department of Mathematics and Physics Shandong Institute of Architecture and Engineering 250014 Jinan China

By employing a model potential including the electron exchange energy, we extend the semiclassical closed orbit theory to study the multielectron atoms. Using special region-splitting consistent and iterative method, we figure out the closed orbits in the corresponding classical system and calculate the recurrence spectra of triplet helium atoms in parallel electric and magnetic fields at scaled energy ε=?0.03,n≈40,n=0. The core-scattering effects have been taken into account, which lead to more peaks in the spectra. It has also been confirmed by means of the direct comparison between the spectral portrait in such a plot and those of hydrogen case. In order to compare the theoretic results with experiment, we investigate the closed orbits and recurrence spectra of helium atoms for the similar exchange potential but applied only by single electric field at scaled energy ε=?2.7 case. The spectra are in good agreement with the experimental observation. We conclude that our model is correct and it is necessary to consider the exchange effect for determining the photoabsorption spectra of multielectron atoms in strong external fields.

关键词： exchange potential, recurrence spectra, semiclassical closed orbit theory, core-scattering.

Study on Community Diversity of Coastal Shelter Forest in Jiaonan

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Chinese Journal of Population,Resources and environment 2005年第3期3卷 42-47页

作者： Xu Jingwei 1,2. Li Chuanrong 3, Li Qi 4, Zheng Li 3, & Wang Weidong 1 1 Beijing Forestry university,Beijing 100871,China 2.shandong Acdemy of Forestry, Jinan 2.0014, China 3 College of Forestry, shandong Agricultural university, Taian 2.1018, China 4 shandong Normal university, Jinan 2.0014, China Beijing Forestry university Beijing 100871 China shandong Acdemy of Forestry Jinan 250014 China College of Forestry Shandong Agricultural University Tatan 271018 China shandong Normal university Jinan 250014 China

Based on the research of the plots in coastal areas in Jiaonan city, shandong Province, the indices of richness, evenness and diversity of different community types are analyzed. The results show that: The richness indices indicates that arbor layers are close to shrub layers, and both are lower than herbage layers; the ranges among communities vary a little except those of the arbor ones. Mostly the biodiversity indices reveal that herbage, the arbor, the shrub; Biodiversity of communities has great influences on microclimate to a certain extent and is under the control of regional environment.

关键词： coastalshelterforest richness biodiversity index microclimate

A theoretical analysis of optical-to-THz conversion efficiency via optical rectification

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Science China(technological Sciences) 2008年第12期51卷 2080-2088页

作者： LI DeHua1,QI XiaoDong2.& LIU ShengGang3 1 Terahertz institute of shandong {2. of Science & techno.ogy,Qingdao 2.6510,China 2.Changchun institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China 3 Terahertz research center,Physical Electronics College,{2. of Electronics Science,Chengdu 610054,China Terahertz institute of shandong {2. of Science & techno.ogy Qingdao 266510 China Changchun institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 China Terahertz research center Physical Electronics College University of Electronics Science Chengdu 610054 China

A theoretical analysis of an ultra-short pulse converted to Terahertz radiation via optical rectification in nonlinear optical crystal is presented here;several factors that affect optical-to-THz conversion efficiencies are discussed;pulse durations affect the conversion efficiency effectively:when crystal length is equal to the optimal crystal length lc,optical-to-THz conversion efficiency is the highest,but for the periodically-inverted electro-optic crystals,conversion efficiency is almost proportional to the crystal length when absorption can be *** account of the absorption of crystals,effective length of crystal is Leff=0.63/α,there is no apparent increase of conversion efficiency and the conversion efficiency approaches to a constant eventually when the crystal length is increased.

关键词： optical rectification periodically inverted effective length conversion efficiency

Monitoring the Cultivated Slope Land in the Three Gorges Reservoir Area Based on Remote Sensing and GIS

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Wuhan university Journal of Natural Sciences 2006年第4期11卷 915-921页

作者： ZHOU Jieming1, ZHOU Qigang 2. 3 ,HUANG Zhiqin 2. 3, 4 1. The Faculty of Geography and Resources Science, Sichuan Normal university, Chengdu 610066, Sichuan, China 2. institute of Mountain Hazards and {2., Chinese Academy of Sciences, Chengdu 610041, Sichuan, China 3. Graduate university of the Chinese Academy of Sciences, Beijing 100049, China 4. Information Center of Land and Resources Department of Sichuan Province, Chengdu 610041, Sichuan, China The Faculty of Geography Resources Science Sichuan Normal University 610066 Chengdu Sichuan China institute of Mountain Hazards environment Chinese Academy of Sciences 610041 Chengdu Sichuan China Graduate university of the Chinese Academy of Sciences 100049 Beijing China Information Center of Land Resources Department of Sichuan Province 610041 Chengdu Sichuan China

By means of combining auto-extraction with manual interpretation, the current distribution information about cultivated land is obtained. The distribution information of 1992.is extracted from the dynamic polygons of 2.02. The monitoring mini-system of the cultivated slope land is established. In the system, detailed surveys, focused on the resources of cultivated slope land, are carried out. The results indicate that the area of the cultivated slope land is very large. Meanwhile, there are lots of cultivated steep slopes with gradient above 35°. The areas of steep land cultivated had been slowly reduced from 1992.to 2.02. At the same time, the pressures of returning farm land to forestry are great in all counties. The conflicts between population growth, insufficient grain supply and stagnant economic development sharpen increasingly. It is inevitable to improve the agricultural structure.

关键词： slope land cultivated remote sensing geography information system (GIS) the pressure of returning farm land to forestry Three Gorges Reservoir Area

Electronic structure and magnetic properties of metastable SmCo_(7) compound

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Science China(Physics,Mechanics & Astronomy) 2005年第3期48卷 325-335页

作者： ZHANG Changwen 1 , LI Hua 1 , DONG Jianmin 1 , WANG Yongjuan 1 , PAN Fengchun 1 , ZHANG Jian 1 , GUO Yongquan 2.& LI Wei 2.1. School of Physics and Microelectronics, shandong {2., Jinan 2.0100, China 2. institute of Functional Materials, Central Iron and Steel Research institute, Beijing 100081, China 1. School of Physics and Microelectronics Shandong University 250100 Jinan China 2. institute of Functional Materials Central Iron and Steel Research Institutes 100081 Beijing China

The electronic density of states, spin-splittings and atomic magnetic moments of SmCo 7 compound have been studied using spin-polarized MS-Xα method. The results show that a few of electrons are transferred to Sm(5d 0 ) orbital because of orbital hybridization between Sm and Co atoms in the compound. The exchange interactions between 3d and 5d electrons lead to the magnetic coupling between Sm and Co, and therefore, result in the long-range ferromagnetic order inside the SmCo 7 compound. There are negative exchange couplings occurring at some levels, which weakens the strength of average coupling around Co lattice. So, the Curie temperature and Co-moment of SmCo 7 decrease distinctly compared with pure Co. Compared with SmCo 5 compound, the disordered substitution of Co-Co “dumbbell-atom” pairs for Sm changes the local environment of Co lattice, which makes the 2. site bear negative magnetic moment. The strength of hybridization near Fermi level weakens and the free energy of the compound increases obviously. Thus, SmCo 7 is a metastable compound at room temperature. Considering the localization of 4f electrons and a few of 5d electrons arising from the orbital hybridization, the magnetic moment of Sm atom will be 1.61μ B in SmCo 7 compound, which is in agreement with the experimental values of Sm 3+ ion- moment and Sm atom-moment in metals.

关键词： electronic structure, spin polarization, atomic magnetic moment, exchange coupling, Curie temperature.

Pickering乳液制备及稳定性研究进展

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化工进展 2024年第4期43卷 2017-2030页

作者：齐亚兵吴子波杨清翠西安建筑科技大学化学与化工学院陕西西安710055 西南化工研究设计院有限公司四川成都610225

Pickering乳液是一类以超细固体颗粒或固态胶体颗粒代替传统表面活性剂作乳化剂而制备的新型乳液,其具有稳定性好、易调控、环境友好、成本低等优点,在石油、水处理、化妆品、食品、医药、材料制备等多个领域得到了广泛应用。基于Picker... 详细信息

Pickering乳液是一类以超细固体颗粒或固态胶体颗粒代替传统表面活性剂作乳化剂而制备的新型乳液,其具有稳定性好、易调控、环境友好、成本低等优点,在石油、水处理、化妆品、食品、医药、材料制备等多个领域得到了广泛应用。基于Pickering乳液的制备和稳定性,本文简述了Pickering乳液的制备方法,介绍了固体乳化剂粒子的类型和研究进展,阐述了Pickering乳液的稳定机制,解析了Pickering乳液稳定性的影响因素,分析了Pickering乳液存在的问题,展望了Pickering乳液的发展方向。未来Pickering乳液的发展主要集中在以下三个方面:①以天然固体纳米粒子或经过各种改性修饰后的天然固体纳米粒子为乳化剂,制备价格低廉、绿色环保、可重复使用的Pickering乳液;②制备智能响应型(温度、pH、磁场等响应型)Pickering乳液,用于材料制备、物质缓释或回收、催化反应等过程;③深入研究不同固体粒子稳定Pickering乳液的机制,精确调控固体乳化剂粒子和乳液的结构,建立Pickering乳液系统制备理论。

关键词： Pickering乳液粒子制备稳定性机制影响因素

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Chronology of Holocene lacustrine sediments in Co Ngoin, central Tibetan Plateau

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Science China Earth Sciences 2006年第9期49卷 991-1001页

作者： WU Yanhong1, WANG Sumin1& HOU Xinhua1,3 1. Key Laboratory of Lake Sedimentation and environment, Nanjing institute of Geography and Limnol{2., Chinese Academy of Sciences, Nanjing 2.0008, China 2. institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 10085, China 3. Graduate university of Chinese Academy of Sciences, Beijing 100039, China 1. Key Laboratory of Lake Sedimentation and environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China 2. institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 10085 China 3. Graduate university of Chinese Academy of Sciences Beijing 100039 China

Chronology is the basis for using lacustrine sediments to reconstruct the history of en-vironmental change. Radioactive-nuclides such as 14C, 2.0Pb and 137Cs dating are mainly used to establish the chronology for recent several ten thousand years. Because of being mixed with “dead carbon”, the measured 14C age is always older than the actual age which is recognized as “reservoir effect”. Cs is a kind of active metal element, and easy to migrate vertically in the sediment that leads to the error of the time marker. 2.0Pb dating should make sure to select CIC model or CRS model. On the Tibetan Plateau, most of the lakes are alkaline closed lake where Cs is more moveable in the sediment and the reservoir effect caused by “dead carbon” on 14C dating is stronger. Based on the analysis on results of 14C, 2.0Pb and 137Cs of the lacustrine sediments from Co Ngoin, central Tibetan Plateau, we use the simple regression method to re-calculate the 14C calendar ages, and establish the time sequence for cores CE-1 and CE-2.with result of 2.0Pb CRS model for the upper 35 cm and re-calculated 14C calendar age for sediments bellow 35 cm. Since 1400 cal. a BP, sedimentation inter-rupted for more than 1000 years. According to this time sequence, variations of {2.al proxies confidently reflect the major climatic events in Holocene.

关键词： 14C, 2.0Pb and 137Cs, chronology, lacustrine sediments, climatic event, Co Ngoin, central Tibetan Plateau.

Atmospheric COremoval efficiency through enhanced silicate weathering in croplands: a review with emphasis on the contribution of fungi

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Journal of Earth Science 2024年

作者： zibo Li Gaojun Li Jonathan M.Adams Dongxing Guan Liang Zhao Rongjun Bian Qing Hu Xiancai Lu Junfeng Ji Jun Chen State Key Laboratory of Palaeobiology and Stratigraphy， Nanjing institute of Geology and Palaeontology， Chinese Academy of Sciences Key Laboratory of Surficial Geochemistry， Ministry of Education， School of Earth Sciences and Engineering and Frontiers Science Center for Critical Earth Material Cycling， Nanjing university School of Geography and Ocean Science， Nanjing university institute of Soil and Water Resources and environmental Science， College of environmental and Resource Sciences， Zhejiang university institute of Resource， Ecosystem and environment of Agriculture， Nanjing Agricultural {2. Xiong'an institute of Innovation， Chinese Academy of Sciences

Enhanced silicate weathering （ESW） is a geoengineering method aimed at accelerating carbon dioxide (CO2. removal （CDR） from atmosphere by increasing the weathering flux of silicate rocks and minerals. It has emerged as a promising strategy for CDR. Theoretical studies underscore ESW’s substantial potential for CDR and its diverse benefits for crops when applied to croplands. However， the well-known significant discrepancies in silicate weathering rates between laboratory and field conditions introduce uncertainty in CDR through ESW. By compiling data from recent literature， we calculated and compared CDR efficiency (t CO2.silicate-1ha-1y-1) observed in mesocosm experiments and field trials. The findings indicate that CDR efficiencies in field trials are comparable to or exceeding that observed in mesocosm experiments by 1-3 orders of magnitude， particularly evident with wollastonite application. The hierarchy of CDR efficiency among silicates suitable for ESW is ranked as follows: olivine ≥ wollastonite > basalt > albite ≥ anorthite. We suggest the potential role of biota， especially fungi， in contributing to higher CDR efficiencies observed in field trials compared to mesocosm experiments. We further emphasize introducing fungi known for their effectiveness in silicate weathering could potentially enhance CDR efficiency through ESW in croplands. But before implementing fungal-facilitated ESW， three key questions need addressing: （i） How does the community of introduced fungi evolve over time? （ii） What is the long-term trajectory of CDR efficiency following fungal introduction? and （iii） Could fungal introduction lead to organic matter oxidation， resulting in elevated CO2.missions? These investigations are crucial for optimizing the efficiency and sustainability of fungal-facilitated ESW strategy.

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