137Cs应用于我国土壤侵蚀研究评述

^137Cs示踪法技术目前已被广泛应用于长期的土壤侵蚀估算中，但主要局限于水蚀研究领域，在风蚀方面进行的研究则较少。土壤风蚀是导致干旱半干旱地区土地退化和区域环境恶化的最重要原因之一。探讨、研究格进一步完善^137Cs技术在土壤侵蚀方面的研究，尤其是在我国西部风蚀地区土壤侵蚀中的应用，可以提供独立的土壤侵蚀和堆积的数据以及空间分布，对初步测算区域风蚀速率、风蚀时间序列和反映环境变化，为我国西部地区土地资源合理利用、环境整治以及生态建设提供定量的科学依据具有十分重要的意义。初步论述了^137Cs技术在我国土壤侵蚀研究中的进展，探讨了其在西部风蚀地区土壤风蚀研究现状、应用前景和需要注意的问题，并提出了一些建议。     

一组Billiard系统的衰减率

对具有慢混合率的奇异动力系统的研究方法是近几年才发展起来的,但应用到具体模型上还比较困难．研究了一组新型的半发散billiards系统．证明该系统碰撞映射的相关函数的收敛速率的上界为（lnn）^3／n^2,其中n表示离散时间．     

Combining exchange rate forecasts: What is the optimal consensus measure?

In this paper a high-quality disaggregate database is utilized to examine whether individual forecasters produce efficient exchange rate predictions and also if the properties of the forecasts change when they are combined. The paper links a number of themes in the exchange rate literature and examines various methods of forecast combination. It is demonstrated, inter alia, that some forecasters are better than others, but that most are not as good as a naive no-change prediction. Combining forecasts adds to the accuracy of the predictions, but the gains mainly reflect the removal of systematic and unstable bias.     

Composite model building for foreign exchange rates

It has been shown in recent economic and statistical studies that composite forecasts may produce more accurate forecasts than individual ones. The purpose of this study is to develop composite forecasting models that may produce forecasts superior to the individual forecast implicit in forward exchange rates. In an efficient market one would expect to find little improvement with the composite models relative to the forward exchange rate.     

Forecasting interest rate swap spreads using domestic and international risk factors: evidence from linear and non‐linear models

This paper explores the ability of factor models to predict the dynamics of US and UK interest rate swap spreads within a linear and a non‐linear framework. We reject linearity for the US and UK swap spreads in favour of a regime‐switching smooth transition vector autoregressive (STVAR) model, where the switching between regimes is controlled by the slope of the US term structure of interest rates. We compare the ability of the STVAR model to predict swap spreads with that of a non‐linear nearest‐neighbours model as well as that of linear AR and VAR models. We find some evidence that the non‐linear models predict better than the linear ones. At short horizons, the nearest‐neighbours (NN) model predicts better than the STVAR model US swap spreads in periods of increasing risk conditions and UK swap spreads in periods of decreasing risk conditions. At long horizons, the STVAR model increases its forecasting ability over the linear models, whereas the NN model does not outperform the rest of the models. Copyright © 2007 John Wiley & Sons, Ltd.     

弹头侵彻高强装甲钢运动规律及弹坑周围塑性切应变分布

探讨弹头侵彻３０ＭｎＣｒＮｉＭｏＢ高强装甲钢的运动规律，确定弹甲相互作用时间（τ），结果表明τ与弹头初速度无关．借助该钢基体内具有的带状组织测量弹坑周围材料塑性切应变呈山峦起伏分布，并给出塑性变形的应变速率（１０４ｓ－１）以及ＡＳＢ形成的应变速率（１０５ｓ－１）．     

考虑红利支付的最优消费投资模型研究

研究了金融市场上证券投资的随机模型。证券价格的波动行为用随机微分方程加以刻划。考虑红利支付过程后，探讨了投资商的最优消费与投资的一般特征。并就模型系数为常系数情形导出反馈形式的最优消费与投资公式。     

2D大U Hubbard模型核自旋驰豫研究

本文从Spinon与2D格点上Cu~( )离子的自旋耦合作用出发,讨论CuO_2平面的2DHubbard模形的自旋格点驰豫率1/T_1。理论计算的结果与氧化物高温超导材料的1/T_1实验结果比较,说明可以用S波超流理论解释实验现象。     

Twisting the Dollar? On the Consistency of Short‐Run and Long‐Run Exchange Rate Expectations

We examine consistency properties of the exchange rate expectation formation process of short‐run and long‐run forecasts in the dollar/euro and yen/dollar market. Applying nonlinear consistency restrictions we show that in a simple expectation formation structure short‐run forecasts are indeed inconsistent with long‐run predictions. Moreover, we establish a ‘twist’ in the dollar/euro expectation formation process, i.e. market participants expect bandwagon effects in the short run, while they have stabilizing expectations in their long‐run forecasts. Applying a panel probit analysis we find that this twisting behavior is more likely to occur in periods of excess exchange rate volatility. Copyright © 2011 John Wiley & Sons, Ltd.     

3组瓶法测定水溶性高聚物的生物降解率

以水溶性聚天冬氧酸壳聚糖共聚物为研究对象，初步建立了一套以聚合物降解3纽瓶即样品瓶、毒性瓶和中性瓶培养为核心内容，包括样品预处理、检测方法选择、结果分析处理等的水溶性高聚物生物降解率测定的基本方法．与常规分析方法相比．一方面本实验方案因增加了中性瓶设计而使得其逻辑性更加严密；另一方面，将聚天冬氨酸壳聚糖共聚物用活性污泥滤液处理28d，由本实验方案得到的生物降解率为55．47％，而常规方法仅为47．51％，前者比后者约高出7．96％．