Improvement on Hot Workability of

［1］Kim Y W. Intermetallics Alloys Based on Gamma Titanium Aluminide [J]. JOM,1989,41(7):24-30. ［2］Kim Y W, Dimiduk D M. Progress in the Understanding of Gamma Titanium Aluminides [J]. JOM,1991,43(8):40-47. ［3］Kim Y W. Ordered Intermetallic Alloys, Part III: Gamma Titanium Aluminides [J]. JOM,1994,46(7):30-39. ［4］Kim Y W. Wrought TiAl Alloy Design [J]. Trans Nonfe-rrous Met Soc China,1999,9(Supp l.1):298-308. ［5］Zhong Zenyong, Zhang Ji, Li Shiqiong, et al. Microstruc-ture Modifications of Wrought and Cast TiAl Alloys [J].Trans Nonferrous Met Soc China,1999,9(Supp l.1):188-196. ［6］Zhang Ji, Zhang Zhihong, Su Xi, et al. Microstructure Prep-aration and Hot-Deformation of Ti-46.2Al-2.0V-1.0Cr-0.5Ni Alloy [J]. Intermetallics,2000,8:321-326. ［7］Hodgson J M, Srinivasan R, Lipsitt H A. The Workability of Some Near Gamma Titanium Aluminide Base Alloys [A]. S Ankem, J A Hall eds. Microstructure/Property Relationships of Titanium Alloys [C], Warrendale: TMS,1994.255-261. ［8］Singh J P, Tuval E, Weiss I, et al. Isothermal Deformation of Gamma Titanium Aluminide [A]. Kim Y W, Wagner R,Yamaguchi M eds. Gamma Titanium Aluminides [C]. War-rendale: TMS,1995.547-554. ［9］Pu Zhongjie. The Study on the Behaviors of Deformation,Fracture and Ductility Approach of TiAl Compound [D].Beijing: Central Iron & Steel Research Institute,1990 (in Chinese). ［10］Su Xi, Li Shiqiong, Zou Dunxu, et al. Study on Hot Deformation Properties of Ti-47Al-2Cr-2Nb-1Mo Alloy [J]. Acta Metallurgica Sinica,1999(Supp l.2):428-430. ［11］Shi Jiandong. The Study on the Influence of Microstructures on Mechanical Properties, and Toughening Approach of TiAl Alloy [D]. Beijing: Central Iron & Steel Research Institute,1994 (in Chinese). ［12］Su Xi, Zhang Ji, Zhang Zhihong, et al. Study on Hot Deformability of Gamma Titanium Aluminide Alloys [J]. Acta Metallurgica Sinica, 1999(Supp l.1):280-283.     

Ionic conduction in BaxCe0.8Pr0.2O3-

[1]Iwahara H,Yajima T,Ushida H.Effect of ionic radii of dopants on mixed ionic conductions (H++O2) in BaCeO3-based electrolytes.SolidState Ionics,1994,70/71:267. [2]Taniguchi N,Yasumoto E,Nakagiri Y,Gamo T.Sensing properties of an oxygen sensor using BaCe0.8Gd0.2O3-a ceram-ics as electrolytes.J.Electrochem.Soc.,1998,145(5):1744. [3]de Arcllano-Lopez A R,Goretta K C,Park E T,Dorris S E,Balchandran U,Routbort J L.High-temperature deformation of a BaCe0.8Y0.2O3-y+Ni composite.J.Fur.Ceram.Soc.,2002,22:2555. [4]Ma G L,Shimura T,Iwahara H.Ionic conduction and non-stoichiometry in BaxCe0.90Y0.10O3-a.Solid State lonics,1998,110:103. [5]Ma G L,Matsumoto H,Iwahara H.Ionic conduction and non-stoichiometry in non-doped BaxCeO3-a.Solid State Ionics,1999,122:237. [6]Ma Guilin,Qiu Ligan,Chen Rong.Performance of the solid oxide fuel cell based on BaxCe0.8Sm0.2O3-a.Acta Chimica Sinica (in Chin.),2002,60(12):2135. [7]Ma G L,Qiu L G,Tao W H,Zhou L,Chen R.Ionic conduc-tion in BaxCe0.8Sm0.2O3-a solid electrolyte.J.Chin.Rare Earths Soc.(in Chin.),2003,21(2):236. [8]Qiu L G,Ma G L,Wen D J.Study on preparation and electri-cal properties of Ba1.03Ce0.8Eu0.2O3-a solid electrolyte.J.Rare Earths,2004,22(5):678. [9]Qiu L G,Ma G L,Wen D J.Ionic conduction in BaxCe0.8Er0.2O3-a.Solid State lonics,2004,166:69. [10]Wang M Y,Qin L G.Mixed conduction in BaCe0.8Pr0.2O3-a ceramic.Chin.J.Chem.Phys.,2008,21:286. [11]Bonanos N.Transport properties and conduction mechanism in high-temperature protonic conductots.Solid State Ionics,1992,53-56:967. [12]Ma G L,Shimura T,Iwahara H.Simultaneous doping with La3+ and y3+ for Ba2+-and Ce4+-sites in BaCeO3 and the ionic conduction.Solid State Ionics,1999,120:51. [13]Shima D,Halle S M.The influence of cation non-stoichiome-try on the properties of undoped and gadolinia-doped barium ceres.Solid State Ionics,1997,97:443.     

贵州喀斯特石漠化地区生态修复现状及治理措施

生态修复一直是脆弱的喀斯特石漠化地区治理的重点和难点.贵州省作为我国西南喀斯特石漠化地区的典型代表,分析了贵州喀斯特石漠化地区生态修复的现状及存在的问题,并有针对性地提出了治理措施,为中国西南喀斯特石漠化其他地区的生态修复提供了科学参考.     

大方县耕地石漠化治理对策探讨

石漠化是指石山区由浓密植被覆盖状态向石漠状态(岩石裸露状态)演变的过程.对石漠化的防治,石化区域生态环境的重建及生态经济开发问题,在发达国家,最普遍的看法和作法是禁伐禁垦,尽量保持原始的自然生态景观,大力发展旅游业.     

基于马尔柯夫模型的石漠化演变趋势研究

在3S技术支持下,利用喀斯特石漠化生态脆弱区贵州清镇市红枫湖示范区2005和2007年的SPOT遥感影像,获取石漠化的转化数据,结合Markov模型确定相应的转移概率矩阵和反演分析,应用SPSS统计分析得出石漠化的未来演变趋势.结果表明,引入Markov模型预测石漠化的变化趋势是可行的,最大误差为7‰,综合误差为1‰;随着石漠化治理工程的开展,研究区内中度石漠化的变化最大,主要转变为潜在和轻度石漠化;到2025年研究区的强度石漠化将得到根本的逆转,转化为潜在石漠化的面积最多为4.07 km2.     

时效温度对二次硬化超高强度钢M54力学性能和组织的影响

试验用M54钢(/%:0.28~0.32C,≤0.10Si,≤0.10Mn,≤0.005S,≤0.008P,9.5~10.5Ni,6.6~7.4Co,1.8~2.2Mo,1.1~1.5W,0.7~1.3Cr,0.04~0.16V)由5.8 t真空感应炉+2.2t真空自耗炉熔炼并锻成Ф170mm棒材。锻材1/2R切取的Ф5mm试样经1075℃90min空冷和1060℃75min油冷固溶处理+在-73℃120min深冷处理+400~600℃300min空冷时效处理。采用光学和扫描电子显微镜等分析研究了时效温度对二次硬化超高强度钢M54的力学性能及组织的影响。结果表明,试验M54钢在520℃300min时效后具有优异的综合力学性能,抗拉强度2040MPa、冲击功62J、断裂韧性110MPa·m~(1/2);在560℃时效时,出现了沿晶断裂形貌,该钢冲击功K_(U2)和断裂韧性K_(IC)分别降至26J和80.6 MPa·m~(1/2),随着时效温度升高至600℃时试验钢的冲击功K_(U2)和断裂韧性K_(IC)分别增加到56 J和131 MPa·m~(1/2)。     

稀土络合物的检验

1960年在巴西SaoPaulo大学化学学院开始研究含氧(作为施主原子)配合机的稀土盐络合物,研究小组由G、Vicentini教授领导,并包括和他一起工作的L、B、Zinnec教授和L、R、F、Carralho,A、M、P、Felicissimo,R、NajiaRr,W、Olireira和J、C、Prado博士。     

钯与氢(H2,D2)反应的热力学性质研究

采用PVT方法精确测定了 40～ 60目的海绵钯 (Pd)粉末在 5～ 5 0℃范围内吸放H2 ,D2 的P C T曲线。结果表明 :2 5℃ ,0 .1MPa时H2 ,D2 在Pd中的溶解度分别为 75 .8和 70 .4ml(STP)·g- 1 Pd;Pd与H2 ,D2 反应的坪台热力学函数分别为 :ΔHa=-18.7kJ·mol- 1 H ,-17.6kJ·mol- 1 D ,ΔSa=-4 6.4J·K- 1 ·mol- 1 H ,-4 9.6J·K- 1 ·mol- 1 D ;ΔHd=2 1.3kJ·mol- 1 H ,18.7kJ·mol- 1 D ,ΔSd=5 0 .8J·K- 1 ·mol- 1 H ,49.1J·K- 1 ·mol- 1 D。H ,D在α相的溶解热力学函数为 :ΔHr→ 0 =-6.5kJ·mol- 1 H ,-5 .6kJ·mol- 1 D ;ΔSr→ 0 =-5 3 .5J·K- 1 ·mol- 1 H ,-5 3 .7J·K- 1 ·mol- 1 D。Pd Q(Q =H ,D)体系存在明显的迟滞效应 ,升高温度可改善吸放氢循环的压力迟滞效应 ,但不能消除。伴随迟滞效应的吉布斯自由能损失 (ΔGloss)在低于 5 0℃时保持不变 ,对Pd H和Pd D体系分别为 1.2 8和 1.2 5kJ·mol- 1 H(D) ;当高于 5 0℃时ΔGloss分别减小约 4%和 11%。     

Critical parameters near the ferromagnetic-paramagnetic phase transition in La0.67–xYxBa0.23Ca0.1MnO3 compounds（x=0.10 and x=0.15）

The critical properties of the mixed manganite La0.67–x Y x Ba0.23Ca0.1Mn O3 with x=0.10 and x=0.15 around the paramagnetic(PM)-ferromagnetic(FM) phase transition were investigated through various techniques. These involved modified Arrott plots, Kouvel-Fisher method and Widom scaling relation. Magnetic data, analyzed in the critical region, using the above methods, yielded the critical exponents for(x=0.10) La0.57Y0.10Ba0.23Ca0.1Mn O3(β=0.312±0.002 and γ=1.147±0.003 at T C=299.23±0.05 K). Moreover, the estimated critical exponents of(x=0.15) La0.52Y0.15Ba0.23Ca0.1Mn O3 were β=0.286±0.004 and γ=0.943±0.002 at T C=289.53±0.06 K. The critical exponents’ values were close to the theoretical values of 3D-Ising model and tricritical mean-field model. These results suggested that the present composition should be close to a tricritical point in the La0.67–x Y x Ba0.23Ca0.1Mn O3 phase diagram. Expressing the field dependence as ΔS M∝H n allowed us to establish a relationship between the exponent n and the critical exponents of the material and to propose a phenomenological universal curve for the field dependence of ΔS M.     

土地整理项目对土地质量的影响评价研究——以河南省长葛市土地整理项目为例

根据土地整理项目的特点,从微地形地貌、土壤、水分、景观因素等方面建立土地整理的土地质量指标体系,并以河南省长葛市土地整理项目区为对象,运用层次分析法确定指标的权重,构建综合评价模型评价了土地整理对土地质量的影响.