江苏省近50a气候干湿特征研究

根据江苏省1960—2009年54个气象台站常规气象观测资料,利用Penman-Monteith公式计算了全省各地区50 a的逐日潜在蒸散量,结合逐日降水量,推算出了相对湿润度指数值,并采用国家标准《气象干旱等级》(GB/T20481-2006)中的相对湿润度分级指标对全省干湿状况进行了评估,分析其时空变化特征。研究表明:1)就全年而言,江苏省半干旱区与湿润区各占50%左右的面积,其中淮北、江淮北部、苏北沿海的北部为半干旱区,江淮南部、苏北沿海的南部、沿江、苏南地区为湿润区;2)降水量和潜在蒸散量是影响相对湿润度指数的两个关键因子,降水量的变化对相对湿润度的时空分布起着主导作用,潜在蒸散量起着辅助作用。3)江苏省1 a中冬季的南北气候干湿反差最大、夏季最小,湿润区范围夏季最大、秋季最小,半干旱区范围秋季最大、夏季没有,干旱区范围春季最大、夏季和秋季没有。夏季气候最湿润、春季气候最干燥。4)淮北和苏北沿海地区的相对湿润度指数年变化呈"单峰型",江淮、沿江和苏南地区的年变化呈"双峰型",苏北沿海地区相对湿润度年内变化最大,沿江地区最小。     

未来气候变化对中国荒漠化的潜在影响

气候变化与荒漠化间的反馈机制已成为全球研究的重点问题之一 ,减缓温室气体增加与防治荒漠化也成为全球协同行动的领域。作为一个发展中国家 ,中国的荒漠化及其防治不仅影响到全球气候变化 ,同时气候变化对中国的荒漠化也会产生显著影响。文中采用全国 1914个气象站的数据作为基线数据 ,在根据植被区划图在青藏高原上对Thornthwaite方程做适当订正的基础上 ,选择未来两个具代表性的年份 (2 0 30年和 2 0 5 6年 )用HadCM 2模型来预测全球变化框架下中国未来荒漠化生物气候类型区的变化。结果表明 ,各生物气候类型区的面积基本上均呈增加的趋势 ,其中以亚湿润干旱区增加为主 ,半干旱区次之。与 1990年的 395 6 5 81万km2 的荒漠化生物气候类型区面积相比 ,在GHGs年增量为 1%且考虑硫酸盐溶胶影响的情况下 ,2 0 30年和 2 0 5 6年分别提高了 11 33%和12 94% ,而在GHGs年增量为 0 5 %且考虑硫酸盐溶胶影响的情况下 ,则分别提高了 3 75 %和6 95 % ,比前者分别减少了 7 5 8和 5 99个百分点。虽然在GHGs年增量 0 5 %的减少情况下 ,中国未来荒漠化生物气候类型区面积扩大和程度加剧的速度有所减缓 ,但其总体增加仍很显著。因此进一步开展气候变化与荒漠化间相互作用的研究 ,并用以指导中国的荒漠化防治工?     

Bulk modulus of Fe-rich olivines corrected for non-hydrostaticity

In situ X-ray diffraction was used to measure the isothermal bulk modulus at room conditions (K_T0) of synthetic olivines with different iron contents. The chemical formulae of the olivine samples were ${({\mathrm{Fe}}_x,{\mathrm{Mg}}_{1?x})}_2\mathrm{Si}{\mathrm{O}}_4$ with x = 0.45; 0.64; 0.82; 1, with 1% standard deviation (referenced as Fa45, Fa64, Fa82 and Fa100, respectively). All experiments were performed in the multi-anvil apparatus installed at NSLS beamline X17B2, to pressures up to about 7 GPa. Unit-cell volumes under hydrostatic conditions and differential stresses present in the samples were calculated using the method developed by Singh et al. (1998), and pressures measured using NaCl as a standard were then corrected for these stresses. Using a second-order Birch–Murnaghan equation of state, we obtained the isothermal bulk modulus of each composition: $K_{T0}^{\mathrm{Fa45}}=131.4\pm 2.6$ GPa, $K_{T0}^{\mathrm{Fa64}}=132.1\pm 3.1$ GPa, $K_{T0}^{\mathrm{Fa82}}=136.3\pm 1.7$ GPa and $K_{T0}^{\mathrm{Fa100}}=134.8\pm 1.4$ GPa. These values combined with data available in the literature show that the K_T0 of Fe-rich olivines increases very slowly with the Fe content, but possibly not in a simple linear trend.     

CTIO1m反射望远镜的色折射改正和星等差

利用ＣＴＩＯ（ＣｅｒｒｏＴｏｌｏｌｏＩｎｔｅｒ－ＡｍｅｒｉｃａｎＯｂｓｅｒｖａｔｏｒｙ）１ｍ反射望远镜观测球状星团ωＣｅｎ区域的Ｖ和Ｂ波段的照相底片，分析研究了色折射改正；描述了测定色折射改工项系数的方法，得到该望远镜在Ｖ和Ｂ波段照相观测的色折射改正项的系数分别为１．３５２１″和４．５４０３″．随后分析讨论了与星等有关的系统误差，结果表明，对大部分照相压片，星等差是很明显的．在利用底片常数归算时，星等的线性和二次项必须包括在内．     

利用元胞自动机计算河道槽蓄量

构建基于元胞自动机的河道水流漫延模型,在该模型中针对河道地形特点处理边界问题,基于水力学中的曼宁公式构建模型局部转换规则,并利用元胞自动机的模拟空间复杂系统动态演变能力的特点,模拟了水流由上断面向下断面流动的动态过程,形成符合上下断面水位的水面,进而计算河道槽蓄量。实验结果表明,把元胞自动机模型引入水文领域计算河道槽蓄量的方法具有可行性。     

New high-pressure phases in BaCO<Subscript>3</Subscript>

Barium carbonate (BaCO₃) was examined in a diamond anvil cell up to a pressure of 73 GPa using an in situ angle-dispersive X-ray diffraction technique. Three new phases of BaCO₃ were observed at pressures >10 GPa. From 10 to 24 GPa, BaCO₃-IV had a post-aragonite structure with space group Pmmn. There are two molecules in a single unit cell (Z = 2) of the orthorhombic phase, which is same as the high-pressure phases of CaCO₃ and SrCO₃. The isothermal bulk modulus of BaCO₃-IV is K ₀ = 84(4) GPa, with V ₀ = 129.0(7) Å³ when K ₀′ = 4. The c axis of the unit cell parameter is less compressible than the a and b axes. The relative change in volume that accompanies the transformation between BaCO₃-III and BaCO₃-IV is ～6%. BaCO₃-V, which has an orthorhombic symmetry, was synthesized at 50 GPa. As the pressure increases, BaCO₃-V is transformed into tetragonal BaCO₃-VI. This transformation is likely to be second order, because the diffraction pattern of BaCO₃-V is similar to that of BaCO₃-VI, and some single peaks in BaCO₃-VI become doublets in BaCO₃-V. After decompression, the new high-pressure phases transform into BaCO₃-II. Our findings resolve a dispute regarding the stable high-pressure phases of BaCO₃.     

宗地面积测量限差的探讨

作者结合工作实践,对地籍调查中宗地面积两次测绘限差分布规律进行了分析,对宗地面积测绘限差公式进行推导,该公式对实际工作有一定的参考作用。     

横向地震波冲击下建筑结构稳定性变化分析

高层EPS法分析横向地震波冲击下建筑结构稳定性变化时,未进行横向地震波随机过程数学模拟,获取的横向地震波与实测不符,提出一种新的横向地震波冲击下建筑结构稳定性变化分析方法,采用三角级数型非平稳随机过程模型函数,模拟横向地震波非平稳性特征,得到横向地震波模拟曲线,根据该曲线建立建筑结构稳定性动力运动方程,运用Hilber-Hughes-Taylor递推格式求解该方程的安全系数,安全系数越高建筑结构稳定性越强。为研究建筑结构在横向地震波反复荷载作用下的稳定性状态,运用弹塑性损伤模型模拟建筑结构核心筒墙体混凝土,得到用于分析建筑结构稳定性的最大、最小特征值。实验结果表明,所提方法能够分析建筑结构稳定性变化,横向地震波冲击前5 s对建筑结构稳定性影响最大。     

Applications of the SW96 formulation in the thermodynamic calculation of fluid inclusions and mineral-fluid equilibria

The SW96 formulation explicit in Helmholtz free energy proposed by Span and Wagner (1996) is the most accurate multifunction equation of state of CO₂ fluid, from which all thermodynamic properties can be obtained over a wide temperature-pressure range from 216.592 to 1100 K and from 0 to 8000 bar with or close to experimental accuracy. This paper reports the applications of the SW96 formulation in fluid inclusions and mineral-fluid equilibria. A reliable and highly efficient algorithm is presented for the saturated properties of CO₂ so that the formulation can be conveniently applied in the study of fluid inclusions, such as calculation of homogenization pressures, homogenization densities (or molar volumes), volume fractions of vapor phase and isochores. Meanwhile, the univariant curves of some typical decarbonation reactions of minerals are calculated with the SW96 formulation and relevant thermodynamic models of minerals. The computer code of the SW96 formulation can be obtained from the corresponding author.