Li+的水合结构和近似饱和水合层:基于密度泛函理论的研究

结合密度泛函理论,运用B3LYP/aug-cc-pVDZ方法对[Li(H₂O)_n]⁺(n=1~10)水合团簇的结构进行了研究。研究结果表明,在气相和液相中,四配位结构的[Li(H₂O)_n]⁺水合团簇比其五配位的异构体稳定,即在水溶液中Li⁺易形成四配位的四面体结构。随着同时水分子数的增加,Li-O键长增大,Li⁺上的电荷密度减小。但是当水分子数大于4时,Li-O键长和Li⁺上的电荷密度变化很小。[Li(H₂O)_n]⁺水合团簇中每个水分子的结合能计算结果表明,7个水分子已足以形成Li⁺的近似饱和水合层。另外红外光谱显示[Li(H₂O)_n]⁺水合团簇中O-H伸缩振动随着水分子数的增加发生蓝移,而~3 600 cm-1和~3 500 cm-1处的吸收峰是第二水合层与第一水合层、第三水合层和第二水合层的水分子形成氢键引起的。     

四苯硼钠—季铵盐质量滴定法分析钾含量研究

依据四苯硼钠—季铵盐容量法滴定K⁺离子的原理,采用质量滴定法,考察了滴定速度、松节油加入量对四苯硼钠与季铵盐反应的影响及共存离子(包括Li⁺、Mg²⁺、Ca²⁺、SO2-₄、B₄O2-₇、CO2-₃)对K⁺含量测定结果的影响。当测定K⁺离子含量在5～15 mg范围内,松节油最佳加入量为25滴,分析误差< 0.3%。     

内蒙古西部地区盐湖水化学特征

2008年9~10月和2009年9月对内蒙古西部地区14个盐湖进行了考察、采样和分析。研究发现,本区盐湖卤水主要离子含量顺序为Na⁺>Cl->SO2-₄>Mg²⁺>K⁺,次要离子为Ca²⁺ >HCO-₃>CO2-₃,微量元素为B₂O₃>Br->Li⁺。Na⁺的分布特征为东部高,北部中等,西南部偏低;而Cl-为东高西低;K⁺大致为南高北低;Mg²⁺为中部高,西部低,北部与南部中等。SO2-₄、 Ca²⁺和CO2-₃的区域分布特征均不明显;微量元素Li⁺ 、Br-、B₂O₃含量虽局部(两大沙漠连接带)有所富集,但绝对含量不高。对天然盐湖和人工采盐池的卤水进行了对比。采盐池中卤水因为蒸发强烈,离子浓度显著高于天然盐湖。分析天然盐湖与采盐池卤水离子浓度的变化规律发现,卤水蒸发初期Na⁺、Cl-、SO2-₄离子浓度随矿化度的升高而增大,Ca²⁺离子浓度明显下降,卤水蒸发后期Mg²⁺、K⁺大量富集,整个卤水蒸发过程中微量元素Li⁺与B₂O₃浓度一直随矿化度的升高而增大。这些结果对内蒙古西部盐湖的研究与开发都具有积极意义。     

Li+,Na+,K+/Cl-,SO2-4-H2O五元体系25 ℃相图及其应用

Li⁺,Na⁺,K⁺/Cl-,SO2-₄-H₂O五元体系相图对于硫酸钠亚型富锂卤水分离提取锂盐、锂辉石加工利用和锂盐产品的开发利用工艺制定都有指导作用。20世纪50年代曾有人研究过这一体系25 ℃时的相图,限于当时的科研水平,液相组成确定不准确,对平衡固相的判断,后来诸多研究结果证明也有错误。50多年来再没有人研究这一五元体系相图。利用我们提出的Li⁺,Na⁺,K⁺/Cl^-,SO^2-₄-H₂O六元体系热力学模型,对该五元体系的平衡溶液组成和正确的平衡固相进行理论预测,给出了该体系的完整相图。结合硫酸锂混盐分离、加工实例阐述了该五元体系相图的应用。     

五硼酸钾溶液中含硼物种的研究

采用物种分布图与核磁共振实验研究了五硼酸钾溶液中含硼物种的类型、含量和溶液浓度间关系。研究表明五硼酸钾在稀溶液(0.05 mol/kg(H₂O))中几乎全部水解,主要物种为B(OH)₃和B(OH)-₄;在较浓溶液(0.20 mol/kg(H₂O))中主要物种为B(OH)₃和B₃O₃(OH)-₄,而B₅O₆(OH)-₄和[B₄O₅(OH)2-₄]的含量较小。核磁共振实验研究给出了B(OH)-₄、B₃O₃(OH)-₄和B₅O₆(OH)-₄的生成常数K₁、K₃,、K₅,研究得出B₅O₆(OH)-₄含量很少的原因是其解聚为其它类型硼酸根离子。外加离子促进五硼酸根离子的生成,而高温条件促进B₅O₆(OH)-₄发生解聚反应。     

Recent Progress on Structure of Aqueous Polyborate Solutions

The crystal structure of metal borates has been extensively investigated by X-ray and neutron diffraction,but,the structure of aqueous polyborate solutions are still largely unknown.Over the last decade,our group has focused on studying the structure of complex aqueous polyborate solutions of Li,Na,K,Rb,Cs,and Mg using synchrotron radiation X-ray scattering(XRS),EXAFS,Raman,NMR,and DFT,as well as determining the density,conductivity and pH of such solutions.Polyborate species distributions were calculated using pH measurements,and the main species in the solution have been confirmed by NMR and Raman spectra.For alkali-metal metaborates,the dominant species is always B(OH)-₄in a wide range of concentration,while the presence of others species is negligible.For alkali metal tetraborates,when concentration is in the extreme low range,only B(OH)₃ and B(OH)-₄ are present in these solutions.As the total boron concentration increases,B(OH)₃ and B(OH)-₄ polycondensated to form more complex oligomers.Of them,while B₄O₅(OH)2-₄ in the tetraborate solutions is the main species,B(OH)₃,B(OH)-₄,and B₃O₃(OH)-₄ are minor species,and B₃O₃(OH)2-₅ and B₅O₆OH)-₄ are present only in negligible amounts.As solution continues to concentrate,B₄O₅(OH)2-₄ eventually becomes the dominant species,which is consistent with the congruent compound M₂B₄O₇·nH₂O(M=Li,Na,K,Rb,Cs) in the system M₂O-B₂O₃-H₂O(M=Li,Na,K,Rb,Cs).For alkali metal pentaborates,B(OH)₃ and B(OH)-₄ are the main species at low concentrations.The species distribution,Raman and NMR spectroscopy results verified that the dominant species in concentrated pentaborate solutions with Li and Na is pentaborate B₅O₆OH)-₄,but it is surprising that the main species with K,Rb,and Cs is always the triborate monoanion B₃O₃(OH)-₄.Although all M[B₅O₆OH)₄]·nH₂O(M=Li,Na,K,Rb,Cs) are all congruent compounds in the system M₂O-B₂O₃-H₂O(M=Li,Na,K,Rb,Cs) ,the main species in aqueous solutions are quite different because of various cation hydration distance(d),hydration number(CN),and configuration,especially charge(Z).For bivalent Mg²⁺,three borate minerals,namely,Inderite(2MgO·3B₂O₃·15H₂O),Hungchaoite(MgO·2B₂O₃·9H₂O),and Mcallisterite(MgO·3B₂O₃·7.5H₂O),exist in the system MgO-B₂O₃-H₂O at 298K.Inderite is a congruent compound,but Hungchaoite and Mcallisterite are incongruent compounds.The species distribution and Raman spectra demonstrat that the predominant species in all the solutions with magnesium borates is bivalent triborate B₃O₃(OH)2-₅,while the subordinate species are B(OH)-₄ at a low B₂O₃/MgO ratio and B(OH)₃at a high B₂O₃/MgO ratio,and the other anions are negligible,as the high Z of the borate anion must match that of Mg²⁺.The disappearance of divalent B₄O₅(OH)2-₄ is in agreement with its incongruent nature.The DFT and XRS results showed that tetrahedral Li(H₂O)⁺₄(d=0.20 nm,CN=4),octahedral Na(H₂O)₆⁺(d=0.236 nm,CN=6),and Mg(H₂O)²⁺₆(d=0.210 nm,CN=6) in the first hydration shell belong to Platonic polyhedra.However,K(H₂O)⁺₈(d=0.28 nm,CN=8,XRS and DFT),Rb(H₂O)⁺₈(d=0.293 nm,CN=7.7-8.2,EXAFS),and Cs(H₂O)⁺₈(d=0.320-0.326 nm,CN=7.6-7.9,EXAFS) are inclined Voronoi polyhedra.Therefore,the effects of cation Z and d on the structure of polyborates in aqueous solutions are deterministic,while the effect of hydrated-cation symmetry is secondary.Their hydrolysis order was:Mg＞Li＞Na＞K＞Rb＞Cs,in step with hydration power.Among them,Mg²⁺ and Li⁺have a strong tendency towards hydrolysis,but Na⁺ scarcely hydrolyzes,especially Rb⁺ and Cs⁺ have a little protonation.X-ray scattering of aqueous alkaline sodium borohydride solutions confirmed that dihydrogen bonds exist in an aqueous solution.The four distinct features of dihydrogen bonds in aqueous solution-unidirectionality,divaricativity,multicentricity,and multidentativity have been also described here in brief.     

Mg(BO2)2在MgSO4和MgCl2-MgSO4水溶液中分解的相平衡与物种化学平衡

硫酸镁亚型盐湖老卤是MgCl₂、MgSO₄的饱和溶液体系,富集了Mg、B、Li等元素。本文针对含硼水盐体系热力学难以表达的问题,开展了硼在水盐体系存在形态及其平衡关系的研究。利用易于水解的Mg(BO₂)₂作为硼源,借助拉曼光谱和X射线衍射(XRD)为检测手段,定量研究Mg(BO₂)₂在MgSO₄-H₂O、MgSO₄-MgCl₂-H₂O体系中水解硼物种转化规律。结果表明:(1)Mg(BO₂)₂在MgSO₄溶液中的水解固相为MgB₂O(OH)6、MgB₄O₇·9H₂O和Mg(OH)₂;在MgSO₄-MgCl₂-H₂O溶液中水解固相为Mg₂B₆O₁₁·15H₂O、MgB₄O₇·9H₂O、Mg₂Cl(OH)₃·4H₂O。(2)Mg(BO₂)₂在MgSO₄溶液中水解,液相硼物种主要有B₃O₃(OH)-₄、B₃O₃(OH)₅2-、B(OH)-₄、B₄O₅(OH)₄2-、H₃BO₃,其分布受MgSO₄浓度影响很大,MgSO₄浓度从0增加至饱和,B₃O₃(OH)-₄始终占总硼量的50.07%以上,B₃O₃(OH)₅2-占液相总硼从4.77%上升至37.16%为第2化学物种。(3)在MgSO₄-MgCl₂-H₂O溶液中,硼物种的主要形态有B₃O₃(OH)-₄、B₃O₃(OH)₅2-、B(OH)-₄,其分布 随[Cl₂2-]/([Cl₂2-]+[SO₄2-])变化很大,在MgCl₂和MgSO₄的共饱溶液中,分别占液相总硼量的58.91%,14.62%和12.81%。(4)液相硼物种之间平衡关系的活度商lnQ,不仅与溶液pH、水活度有关,还与MgSO₄、MgCl₂摩尔浓度呈二元线性关系,这样就可将硼在H₃BO₃-NaOH体系物种分布关系的lnQ扩展到 (MgSO₄,MgCl₂,MgSO₄-MgCl₂)水溶液的多元体系。由此获得硼物种的量化关系,可为推算硼在水盐体系的物种分布,进而计算含硼电解质溶液热力学性质提供依据。     

Na+,K+,Rb+,Cs+//SO2-4-H2O体系固液相平衡热力学模拟

锂云母、铯榴石等矿物的硫酸盐焙烧浸出,是从中提取锂铷铯钾等碱金属元素的重要步骤,所得硫酸盐浸出液可近似看作Li⁺,Na⁺,K⁺,Rb⁺,Cs+ // SO₄2--H₂O六元水盐体系;其在浓缩过程呈现复杂的成盐特征,增加了各碱金属元素分离提取的难度,研究其相关水盐体系相图和相平衡性质对理解浸出液中碱金属的分离具有重要的理论指导意义。本文采用Pitzer-Simonson-Clegg超额Gibbs自由能方程和具有内在热力学一致性的CALPHAD方法,构建了Na⁺,K⁺,Rb⁺,Cs⁺//SO₄2--H₂O五元体系的多温固液相平衡热力学模型。借助该模型:1)实现了对Na₂SO₄₊Rb₂SO₄₊H₂O、Na₂SO₄₊Cs₂SO₄₊H₂O和K₂SO₄₊Cs₂SO₄₊H₂O三元体系的多温溶解度等温线的准确描述,并进一步构建了这些体系在240.15~380.15 K温度范围内的多温相图;2)实现了对K₂SO₄+Rb₂SO₄₊H₂O和Rb₂SO₄₊Cs₂SO₄₊H₂O体系中存在的固溶体相—水溶液平衡关系的准确描述,确认了(K,Rb)₂SO₄连续固溶体、以及(Rb,Cs)₂SO₄(α)和(Rb,Cs)₂SO₄(β)间断固溶体存在的合理性;3)预测了上述五元体系中所包含的全部4个四元子体系(Na₂SO₄₊ K₂SO₄₊ Rb₂SO₄+H₂O、Na₂SO₄ + K₂SO₄₊Cs₂SO₄₊ H₂O、Na₂SO₄₊ Rb₂SO₄₊Cs₂SO₄ + H₂O和K₂SO₄₊Rb₂SO₄₊Cs₂SO₄₊ H₂O)的相图,明确了四元相图中固溶体的类型及形成区域。然而,模型预测结果与现有四元体系实验数据间存在普遍的不一致性,尤其是固溶体形成区域,但模型预测结果从非实验角度给出了重要参考,对现有实验提出了挑战,未来对这些体系开展更为精细的实验研究非常必要。     

球形MnO2·0.5H2O提锂性能及其机理研究

考察了形貌对尖晶石型锂离子筛吸附剂MnO₂·0.5H₂O吸附性能的影响。实验证明,反应物Mn₂O₃的形貌在很大程度上决定了前驱体及其吸附剂的形貌。采用XRD、SEM、TEM、FT-IR、XPS和N₂吸附—解吸等温线等对样品进行了表征。表征和吸附实验结果表明,与立方形锂离子筛相比,球形锂离子筛具有较高的吸附容量(42.46 mg/g),同时对溶液中的Li⁺具有较高的选择性。表面脱质子和离子交换过程的共同作用增强了离子筛型吸附剂的提锂Li⁺性能。此外,本文对Li1.6Mn1.6O₄与MnO₂·0.5H₂O的吸附—解吸机理进行了解释。     

硝酸盐氮同位素指示的青海湟水河中可能的氮污染来源

系统测定了青海湟水河枯水期河水的硝酸盐(NO-₃)含量及其氮同位素组成(δ¹⁵N-NO-₃),详细分析了青海湟水河流域硝酸盐浓度及氮同位素组成的变化特征,基于此初步探讨了河水中可能的氮污染来源。结果显示,研究时段内湟水河河水的NO-₃浓度范围为0.1~38.0 mg/L,平均值为15.9 mg/L,约56%的河水样品中的NO-₃含量超过我国《地表水环境质量标准》中V类水氮含量的标准限值。湟水河河水δ¹⁵N-NO-₃值的变化范围为+2.7‰~+16.8‰,平均值为+8.5‰,反映出受不同氮来源的影响。总体而言,湟水河NO-₃浓度自源头至下游整体呈增大趋势,但各区段δ¹⁵N-NO-₃值的变化幅度却存在较大差异。对比分析发现,流域内河水较高的δ¹⁵N-NO-₃值可能指示河水中的硝态氮主要来源于工业生产以及人类生活排放的污水或粪便;而较低的δ¹⁵N-NO-₃值指示河水中的硝态氮主要来源于大气氮沉降或与农业活动有关的土壤。     

BOOK REVIEWS

Book Reviewed in this article: Development and Environment in Peninsular Malaysia . S. Robert Aiken, Colin H. Leigh, Thomas R. Leinbach, Michael R. Moss. The Rural-Urban Fringe: Canadian Perspectives . Ken B. Beesley and Lorne H. Russwurm, eds. Women and Development . Lourdes Benería, ed. The Border that Joins: Mexican Migrants and U.S. Responsibility . Peter G. Brown and Henry Shue, eds. Cities of the World: World Regional Urban Development . Stanley D. Brunn and Jack L. Williams, eds. Time Resources, Society, and Ecology: On the Capacity for Human Interaction in Space and Time (Vol. I, Preindustrial Societies). Tommy Carlstein. Urban Geography . David Clark. Spanish City Planning in North America . Dora P. Crouch, Daniel J. Garr, and Axel I. Mundigo. Not On Our Street: Community Attitudes to Mental Health Care . M. J. Dear and S. M. Taylor Unequal growth: Urban and Regional Employment Change in the U.K. Stephen Fothergill and Graham Gudgin. Agricultural Land in an Urban Society . Owen J. Furuseth and John T. Pierce. The Petroleum Industry in Oil-Importing Developing Countries . Fariborz Ghadar. Historical Understanding in Geography, An Idealist Approach . Leonard Guelke. Regional Planning in Europe . R. Hudson and J. R. Lewis, eds. Remote Sensing for Resource Management . Chris J. Johannsen and James L. Sanders, eds. Geography and The State . R. J. Johnston. Texas Graveyards: a Cultural Legacy . Tlrry G. Jordan. The Politics of Location: An Introduction . Andrew Kirby. A Social Geography of the City . David Ley. Energy and the Future . Douglas MacLean and Peter Brown, eds. The Natural Environment of Newfoundland Past and Present . A. G. Macpherson and J. B. Macpherson, eds. Tourism: Economic, Physical and Social Impacts . Alister Mathieson and Geoffrey Wall. Railroads and Land Grant Policy: A Study in Government Intervention . Lloyd J. Mercer. Progress in Rural Geography . Michael Pacione, ed. Progress in Urban Geography . Michael Pacione, ed. Models of Spatial Inequality: Settlement Patterns in Historical Archaeology . Robert Paynter. Natural Hazard Risk Assessment and Public Policy, Anticipating the Unexpected . William J. Petak and Arthur A. Atkisson. The Nature of Geomorphology . Alistair F. Pitty. Regional Conflict and National Policy . Kent A. Price Women and Spatial Change: Learning Resources for Social Science Courses . Arlene C. Rengert and Janice J. Monk, eds. Urban and Regional Analysis for Development Planning . Richard Rhoda. Rivers: Form and Process in Alluvial Channels . Keith Richards. This Remarkable Continent: An Atlas of United States and Canadian Society and Culture . John F. Rooney, Jr., Wilbur Zelinsky, and Dean R. Louder, gen. eds. The Origins of Open-Field Agriculture . Trevor Rowley, ed. Residential Location Determinants of the Older Population . Gundars Rudzitis. Borderland Sourcebook: A Guide to the Literature on Northern Mexico and the American Southwest . Ellwyn R. Stoddard, Richard L. Nostrand, and Jonathan P. West, eds. Arctic and Antarctic . David Sugden. Tall Timbers Ecology and Management Conference, February 22–24, 1979, Proceedings No. 16 . Graphic Communication and Design in Contemporary Cartography (Progress in Contemporary Cartography , Vol. II). D. R. Fraser Taylor, ed. Living with Energy Shortfall: A Future for American Towns and Cities . Jon Van Til. The United States: Habitation of Hope . J. Wreford Watson. Air Photo Interpretation for Archaeologists . D. R. Wilson. Urban and Rural Change in West Germany . Trevor Wild, ed. Population and Resources . Harry Robinson.     

Assessment of GIAHS in Shizuoka: The Traditional Tea-grass Integrated System

<正>1 Introduction In 2013,Chagusaba,which is traditional tea-grass integrated system in Shizuoka,were accepted as new world heritage site of agriculture.Shizuoka prefecture occupies a variety of elevations,from 0 to 3000m or more above sea level.Because of the diversity of land features and climates,this area produces 167 agricultural commodities.In addition,a lot of traditional agriculture and over200 local native varieties of crops have been conserved in Shizuoka     

ERAHS: A New Platform for the Exchange of Regional Information and Experience on Agricultural Heritage Systems

<正>There are more than 10000 years of agricultural development history in the world that has provided very fruitful and ingenious traditional knowledge and experiences reflecting the evolution of humanity and the nature.In2002,the Food and Agriculture Organization of the United Nations(FAO)initiated an international partnership initiative of"Conservation and Adaptive Management of Globally Important Agricultural Heritage Systems     

BOOK REVIEWS

Book Reviewed in this article: Geography and the Third World. International Seminar, 14–18 May 1980, Kuala Lumpur, Malaysia . Ishmail Ahmad and Jamaluddin Md Jahi, eds. The Growth Dilemma: Residents' Views and Local Population Change in the United States . Mark Baldassare. Sport and Place: A Geography of Sport in England, Scotland & Wales . John Bale. The Deindustrialization of America: Plant Closings, Community Abandonment, and the Dismantling of Basic Industry . Barry Bluestone and Bennett Harrison. Selected Essays 1963–1975: Carl O. Sauer . Bob Callahen, ed. Housing and Planning in the Countryside . G. Clark. Conflict, Politics and the Urban Scene . Kevin R. Cox and R. J. Johnston, eds. Thematic Maps: Their Design and Production . David J. Cuff and Mark T. Mattson. Wine: A Geographic Appreciation . Harm Jan de Blij. USSR in Maps . J. C. Dewdney. Political Geography: A Contemporary Perspective . Ramesh D. Dikshit. Rethinking Human Adaptation . Rada Dyson-Hudson and Michael A. Little, eds. Sacred Sands: The Struggle for Community in the indiana Dunes . J. Ronald Engel. Geography of the Biosphere . A. Furley and Walter W. Newey. Disaster and Reconstruction . Robert Geipel. Glasgow: The Making of a City . Andrew Gibb. Design for Arid Regions . Giden S. Golany, ed. Urbanization and Cancer Mortality: The United States Experience, 1950–1975 . Michael R. Greenberg. Geology in the Nineteenth Century: Changing Views of a Changing World . Mott T. Greene. Colonización y Destrucción de Bosques en Panamá . Stanley Heckadon Moreno and Alberto McKay, eds. Urban Geography: A First Approach . David T. Herbert and Colin J. Thomas. The Visual and Spatial Structure of Landscapes . Tadahiko Higuchi. Climate from Tree Rings . M. K. Hughes, P. M. Kelly, J. R. Pilcher, and V. C. LaMarche, Jr., eds. The structure of Nineteenth Century Cities . James H. Johnson and Colin G. Pooley, eds. The American Planner: Biographies and Recollections . Donald A. Krueckeberg, ed. Urban Land Policy For the 1980s, the Message for State and Local Government . George Lefcoe, ed. Regional Planning: Evolution, Crisis and Prospects . Gill C. Lim, ed. Relevance and Ethics In Geography . Bruce Mitchell and Dianne Draper. China: The Geography of Development and Modernization . Clifton W. Pannell and Laurence J. C. MA. The Urban Retailing System . Robert B. Potter. Hants. Nonconventional Energy Resources . Philip R. Pryde. Caribbean Migrants: Environment and Human Survival on St. Kitts and Nevis . Bonham C. Richardson. Population and Resources . Harry Robinson. East Los Angeles: History of A Barrio . Ricardo Romo. Integrated Impact Assessment . Frederick A. Rossini and Alan L. Porter, eds. Environmental Aesthetics: Essays in Interpretation . Barry Sadler and Allen Carlson, eds. Earthwatch . Charles Sheffield. Field Techniques and Research Methods in Geography . Robert H. Stoddard. Haiti: Land of Poverty . Robert J. Tata. Weathering and Erosion: Sources and Methods in Geography . Stephen T. Trudgill. Once Beneath the Forest. Prehistoric Terracing in the Río Bec Region of the Maya Lowlands . B. L. Turner, II. The Historical Geography of Scotland since 1707 . David Turnock.     

BOOK REVIEWS

Book Reviewed in this article: The City in Cultural Context . John Agnew, John Mercer, David Sopher, eds. Soils and Geomorphology Peter W. Birkeland. Urbanization and Settlement Systems, International Perspectives . L. S. Bourne, R. Sinclair, and K. Dziewoński. eds. An Introduction to Urban Historical Geography . Harold Carter. Overshoot, The Ecological Basis of Revolutionary Change . William J. Catton, Jr. Rivers of the World . Eberhard Czaya. Jewish Communities in Frontier Societies: Argentina, Australia and South Africa . Daniel J. Elazar with Peter Medding. Color in Public Spaces: Toward a Communication-Based Theory of the Urban Built Environment. Kenneth E. Foote. Spatial Statistics and Models. Gary L. Gaile and Cort J. Willmott, eds. Mega-Geomorphology. Rita Gardner and Helen Scoging, eds. Technological Change and Regional Development. Gillespie, ed. The Arid Lands: Their Use and Abuse. R. L. Heathcote. The Location of Industry in Britain. A. G. Hoare. Groundwater as a Geomorphic Agent . R. G. LaFleur, ed. Rural Public Services: International Comparisons. Richard E. Lonsdale and Gyorgy Enyedi, eds. Saving Water in a Desert City. William E. Martin, Helen M. Ingram, Nancy K. Laney, and Adrian H. Griffin. Water Resources: Distribution, Use and Management. John R. Mather. Transnationals and the Third World: The Struggle for Culture. Armand Mattelart. South Hadley, MA: USGS Digital Cartographic Data Standards. R. B. McEwen, R. E. Witmer, and B. S. Ramey, eds. The Ecosystem Concept in Anthropology. Emilio F. Moran, ed. Boulder, CO: Women, Men, and the International Division of Labor. June Nash and Maria Patricia Fernandez-Kelly, eds. Nuclear Power: Assessing and Managing Hazardous Technology. Martin J. Pasqualetti and K. David Pijawka, eds. Mary Somerville and the Cultivation of Science 1815-1840. Elizabeth Chalmers Patterson. An Introduction to Coastal Geomorphology. John Pethick. Late Quaternary Environments of the United States , Vol. 1, The Late Pleistocene. Stephen C. Porter, ed. Planning and Ecology. R. D. Roberts and T. M. Roberts, eds. Regionalism and the Pacific Northwest. William G. Robbins, Robert J. Frank, and Richard E. Ross, eds. Environment and Health. Anthony J. Rowland and Paul Cooper. Sunbelt/Snowbelt: Urban Development and Regional Restructuring. Larry Sawers and William K. Tabb, eds. The Bad Earth. Environmental Degradation in China. Vaclav Smil. Armonk, NY: Voyage into Substance: Art, Science, Nature, and the Illustrated Travel Account, 1760–1840. Barbara Maria Stafford. The Institute of British Geographers: The First Fifty Years. Robert W. Steel. Visions of the Past. Christopher Taylor and Richard Muir. Glacial Lake Agassiz. J. T. Teller and Lee Clayton, eds. The Tule Breakers: The Story of the California Dredge. John Thompson and Edward A. Dutra. The Balkan City 1400–1900. Nikolai Todorov. Explanation, Prediction and Planning: the Lowry model. Michael J. Webber. Mercedes Reales: Hispanic Land Grants of the Upper Rio Grande Region. Victor Westphall. The World Atlas of Revolutions. Andrew J. M. Wheatcroft. The West European City, A Social Geography. Paul White. Urban Elites and Mass Transportation. J. Allen Whitt. Princeton, NJ: Urban Life In Contemporary China. Martin King Whyte and William L. Parish. The Demand for Energy in the Soviet Union. David Wilson. London and Canberra: Rethinking Geographical Inquiry. J. David Wood, ed.     

PRODUCTIVITY OF AMERICAN PH.D.-GRANTING DEPARTMENTS OF GEOGRAPHY

Reviews of geographic software in this article:

DEMO-GRAPHICS: WORLD POPULATIONS AND PROJECTIONS.

ESP

GAUSS.

CEMODEL S. Damus

LIMDEP. William H. Greene

MICROSTAT 4.1

OTIS

PCIPS. (Personal Computer Image Processing System). H.J. Meyers and R. Bernstein.

REGRESSION ANALYSIS OF TIME SERIES (RATS)

SPSS/PC+

URBAN DATA MANAGEMENT SOFTWARE (UDMS)     

BOOK REVIEWS

Book Reviewed in this article: Rabat: Urban Apartheid in Morocco . Janet Abu -Lughod . Marketplaces in a Developing Country: The Case of Western Nigeria . Isaac Ayinde Adalemo . Farming Development and Space: A World Agricultural Geography . Bernd Andreae . Section and Party: A Political Geography of American Presidential Elections, from Andrew Jackson to Ronald Reagan . J. Clark Archer and Peter J. Taylor . Women and Space: Ground Rules and Social Maps . Shirley Ardener , ed. European Progress in Spatial Analysis . R. J. Bennett , ed. The Origins of Academic Geography in the United States . Brian W. Blouet Geographic Perspectives on Global Problems . Ronald Reed Boyce . Seasonal Dimensions to Rural Poverty . Robert Chambers , Richard Longhurst and Arnold Pacey eds. The New Nationalism and the Use of Common Spaces: Issues in Marine Pollution and the Exploitation of Antarctica . Jonathan I. Charney , ed. Communications Tomorrow: The Coming of the Information Society . Edward Cornish , ed. The Design of Suburbia . Arthur Edwards . Explorer on the Northern Plains: Lieutenant Gouverneur K. Warren's Preliminary Report of Explorations in Nebraska and Dakota in the Years 1855–56–57. With an Introduction by Frank N. Schubert . The Changing Climate: Responses of the Natural Flora and Fauna . Michael J. Ford . Essentials of Physical Geography . Robert E. Gabler , Robert J. Sager , Sheila Brazier , and Daniel L. Wise. The Road to Jaramillo . William Glen . Valued Environments . John R. Gold and Jacquelin Burgess , eds. Proximity and Preference: Problems in the Multidimensional Analysis of Large Data Sets . Reginald G. Golledge and John N. Rayner , eds. A Search for Common Ground . Peter Gould and Gunnar Olsson , eds. Geography: Its History and Concepts . Arild Holt -Jensen . A Population Geography . Huw R. Jones . The Human Mosaic: A Thematic Introduction to Cultural Geography, 3rd ed. Terry G. Jordan and Lester Rowntree . Urban Social Geography: An Introduction . Paul Knox . The Anatomy of Job Loss: The How, Why and Where of Employment Decline . Doreen Massey and Richard Meegan . The Information Society as Post-Industial Society . Yoneji Masuda . Map Librarianship, 2nd ed. Harold Nichols . India: Cultural Patterns and Processes . Allen G. Noble and Ashok K. Dutt , eds. The God that Limps: Science and Technology in the Eighties . Colin Norman . Geography: An Introductory Perspective . Robert E. Norris , Keith D. Harries and John D. Vitek . The Politics of Technology Assessment . David M. O'Brien and Donald A. Marchand . Ethnic Segregation in Cities . Ceri Peach , Vaughan Robinson and Susan Smith , eds. Churches and Church Membership in the United States, 1980 . Bernard Quinn , Herman Anderson , Martin Bradley , Paul Goetting and Peggy Shriver . Energy in Australia: Politics and Economics . Hugh Saddler . Development from Above or Below? The Dialectics of Regional Planning in Developing Countries . Walter B. Stóuhr and D. R. Fraser Taylor , eds. Human Impact on the Ecosystem . Joy Tivy and Greg O'Hare . Plants and People: Vegetation Change in North America . Thomas R. Vale . The Mapmakers: The Story of the Great Pioneers in Cartography from Antiquity to the Space Age . John Noble Wilford .     

Deserts and Aeolian Desertification in China: Book review and some thoughts

Desertification is a global phenomenon that affects about two billion people. It occurs in arid zones where the annual precipitation is below 400 mm, partic- ularly in the marginal areas of the world＇s largest deserts. It is a result of water and wind erosion, over- grazing, global warm-ing, improper soil cultivation, and increased pressure ot population growth, and it causes degradation of soil and natural and agricultural vegetation. The direct result is less food for people and livestock, which influences pop- ulation and animal husbandry fluctuations. Despite ef- forts to combat and reduce desertification, the affected areas are annually increasing.     

BOOK REVIEWS

Book Reviewed in this article: The Rice Economy of Asia . Randolph Barker and Robert W. Herdt with Beth Rose. Using Microcomputers: A Guidebook for Writers, Teachers, and Researchers in the Social Sciences . Blaine A. Erie—the Lake that Survived . Noel M. Burns. Geology and Society . Donald R. Coates. Caves and Karst of Kentucky . Percy H. Dougherty, ed. Altered Harvest: Agriculture, Genetics, and the Fate of the World's Food Supply . Jack Doyle. The Middle East and North Africa, A Political Geography . Alasdair Drysdale and Gerald H. Blake. Clamor at the Gates. The New American Immigration . Nathan Glazer, ed. Development and the Landowner: An analysis of the British experience . Robin Goodchild and Richard Munton. Discovering Landscape in England and Wales . Andrew Goudie and Rita Gardner. The Modern Plantation in the Third World . Edgar Graham and Ingrid Floering. Social Relations and Spatial Structures . Derek Gregory and John Urry, eds. The World Food Problem 1950–1980 . David Grigg. Costa Rica: A Geographical Interpretation in Historical Perspective . Carolyn Hall. The Urbanization of Capital: Studies in the History and Theory of Capitalist Urbanization . David Harvey Consciousness and the Urban Experience: Studies in the History and Theory of Capitalist Urbanization . David Harvey. Reviving Main Street . Deryck Holdsworth, ed. Rural Roads and Poverty Alleviation . John Howe and Peter Richards, eds. Uneven Development in Southern Europe: Studies of Accumulation, Class, Migration and the State . Ray Hudson and Jim Lewis, eds. Karst Geomorphology . J. N. Jennings. The Geomorphology of North-west England . R. H. Johnson, ed. Climate Impact Assessment: Studies of the Interaction of Climate and Society . Robert Kates, Jesse Ausubel, Mimi Berberian, eds. Public Service Provision and Urban Development . Andrew Kirby, Paul Knox, and Steven Pinch, ed. State and Market: The Politics of the Public and the Private . Jan-Erik Lane, ed. Living Cities . Twentieth Century Fund Task Force on Urban Preservation Policies. World Climatic Systems . John G. Lockwood. Urban Ethnicity in the United States. New Immigrants and Old Minorities . Lionel Maldonaldo and Joan Moore, eds. Culture and Conservation: The Human Dimension in Environmental Planning . Jeffrey A. McNeely and David Pitt, eds. The Andean Past. Land, Societies, and Conflicts . Magnus Mörner. Gaia: An Atlas of Planet Management . Norman Myers, ed. Progress in Industrial Geography . Michael Pacione, ed. Progress in Political Geography . Michael Pacione, ed. Rivers and Landscape . Geoff Petts and Ian Foster. Urbanization and Planning in the 3rd World: Spatial Perceptions and Public Participation . Robert B. Potter. One Island, Two Nations? A Political Geographical Analysis of the National Conflict in Ireland . D. G. Pringle. Circulation in Third World Countries . R. Mansell Prothero and Murray Chapman. The Ozarks Outdoors: A Guide for Fishermen, Hunters, and Tourists . Milton D. Rafferty. Suburban Burglary: A Time and a Place for Everything . George Rengert and John Wasilchick. Geomorphology and Soils . K.S. Richards, R.R. Arnett, and S. Ellis, eds. The Homes and Homeless of Post-War Britain . Frederick Shaw. Indochinese Refugees in America . Paul J. Strand and Woodrow Jones, Jr. Wild Horses and Sacred Cows . Richard Symanski. Forever Wild: Environmental Aesthetics and the Adirondack Forest Preserve . Philip G. Terrie. The Regional Economic Impact of Technological Change . A.T. Thwaites and R.P. Oakey, eds. The Good Life . Yi-Fu Tuan.