利用单台地磁数据估算Ap和Kp指数的可行性分析

通过分析单台长期地磁场扰动幅度和地磁行星指数Ap和Kp关系,对1小时磁扰幅度r_H的日平均与Ap进行拟合,快速估算Ap指数。对3小时内r_H的平均与Kp进行对数拟合,估算Kp指数。采用肇庆地震台2003—2008年地磁H分量分钟值数据,估算行星Ap和Kp指数,与世界数据中心(WDC)给出的Ap和Kp指数进行统计分析。结果发现,根据上述方法,利用肇庆地震台地磁数据估算Ap和Kp指数,在一定误差范围内可行。

从两种煤的浮沉试验数据估算其可磨性

对一种炼焦煤和一种非炼焦煤所做的研究表明， 煤的可磨性由其各密度组分的可磨性和各密度组分所占的质量百分数所决定。虽然这两种煤各密度组分的可磨性变化有规则， 但仍能发现其变化趋势有一定差别。对炼焦煤来说， 最大密度组分比其他组分更易磨。研究结果证明了根据累计平均密度和逐次密度组分的累计浮物的哈氏可磨性指数间的经验关系式和利用浮沉试验数据来准确估算这两种煤可磨性的可能性。

稻曲病产量损失测定及经济阈值初探

稻曲病单穗病粒数与空瘪率、千粒重、产量损失率均存在极显著相关关系。对稻曲病按病粒数多少进行分级，得出病情指数（Ｘ）与产量损失率（Ｙ）的关系符合如下方程：中籼稻，Ｙ１＝－２．６９９＋０．５８７Ｘ１，ｒ１＝０．９９２**；中粳稻，Ｙ２＝－３．８３９＋０．５５１Ｘ２，ｒ２＝－０．９９８**。根据防治成本、稻谷价格等，导出稻曲病的经济阈值：病情指数中籼稻为１０．４，中粳稻为１３．２。

Enthalpies Estimation of Formation of Monosubstituted Alkanes by Interaction Potential Index

The interaction potential index IPI（X） of 16 Br, C1, I, NO2, CN, CHO, COOH, CH3, CH： kinds of substituents X （X---OH, SH, NH2, ：CH2, C-CH, Ph, COCH3, COOCH3） were proposed, which are derived from the experimental enthalpies of formation △fHФ （g） values of monosubstituted straight-chain alkanes. Based on the IPI（X） and polarizability effect index, a simple and effective model was constructed to estimate the △fHФ （g） values of monosubstituted alkanes RX （including the branched derivatives）. The present model takes into account not only the contributions of the alkyl R and the substituent X, but also the contribution of the interaction between R and X. Its stability and prediction ability was confirmed by the results of leave-one-out method. Compared with previous reported studies, the obtained equation can be used to estimate enthalpies of formation for much more kinds of monosubstituted alkanes with less parameters. Thus, it is recommended for the calculation of the △fHФ（g） for the RX.

Estimating Fraction of Photosynthetically Active Radiation of Corn with Vegetation Indices and Neural Network from Hyperspectral Data

The fraction of photosynthetically active radiation （FPAR） is a key variable in the assessment of vegetation productivity and land ecosystem carbon cycles. Based on ground-measured corn hyperspectral reflectance and FPAR data over Northeast China, the correlations between corn-canopy FPAR and hyperspectral reflectance were analyzed, and the FPAR estimation performances using vegetation index （VI） and neural network （NN） methods with different two-band-combination hyperspectral reflectance were investigated. The results indicated that the corn-canopy FPAR retained almost a constant value in an entire day. The negative correlations between FPAR and visible and shortwave infrared reflectance （SWIR） bands are stronger than the positive correlations between FPAR and near-infrared band re- flectance （NIR）. For the six VIs, the normalized difference vegetation index （NDVI） and simple ratio （SR） performed best for estimating corn FPAR （the maximum R2 of 0.8849 and 0.8852, respectively）. However, the NN method esti- mated results （the maximum Rz is 0.9417） were obviously better than all of the VIs. For NN method, the two-band combinations showing the best corn FPAR estimation performances were from the NIR and visible bands; for VIs, however, they were from the SWIR and NIR bands. As for both the methods, the SWIR band performed exceptionally well for corn FPAR estimation. This may be attributable to the fact that the reflectance of the SWIR band were strongly controlled by leaf water content, which is a key component of corn photosynthesis and greatly affects the absorption of photosynthetically active radiation （APAR）, and makes further impact on corn-canopy FPAR.

Estimates of Central Moments for One Kind of Exponential-Type Operators

In this paper,the explicit estimates of central moments for one kind of exponential-type operators are derived.The estimates play an essential role in studying the explicit approximation properties of this family of operators.Using the proposed method,the results of Ditzian and Totik in 1987,Guo and Qi in 2007,and Mahmudov in 2010 can be improved respectively.

Isotropic Double Index for Quantum Errors in One Qubit

This article describes a proposal for a double index to estimate the isotropic components of unitary errors in a quantum computation circuit. In the context of this work the error is considered isotropic if it has spherical symmetry about the state of interest. The theoretical definition is given, as well the numerical approximation for practical purposes. The index is tested in some simple examples and the geometric distortion of the propagated error is studied for an inaccurate Shor 9-qubits correcting code.

航空发动机污染物排放量估算方法

借助发动机性能模型,研究了发动机性能退化对氮氧化物(NOx)、一氧化碳(CO)、未燃碳氢化合物(UHC)与碳烟颗粒(Soot)排放的影响,提出了基于飞行参数与发动机性能模型的污染物排放总量估算方法。利用ICAO排放数据拟合得到发动机地面状态下的参考排放指数,利用相对法模型得到飞行状态下的排放指数,根据航班飞行参数和发动机性能模型估算航班污染物排放总量。研究结果表明:性能退化对污染物的排放指数影响较大,仅考虑进对燃油消耗量的影响,性能退化对NOx排放总量的影响较小,但会引起CO、UHC与Soot排放总量的上升。执行中短途航班的双发民航飞机的NOx排放总量最高约为100kg,其次为CO,约为20kg,而UHC和Soot的排放总量较低,小于1kg。老化发动机的CO、UHC与Soot的排放总量增加约为10%,而NOx排放总量增加约为2%。

Estimating Soil Salinity in the Yellow River Delta, Eastern China——An Integrated Approach Using Spectral and Terrain Indices with the Generalized Additive Model

Soil salinity is one of the most severe environmental problems worldwide. It is necessary to develop a soil-salinity-estimation model to project the spatial distribution of soil salinity. The aims of this study were to use remote sensed images and digital elevation model(DEM) to develop quantitative models for estimating soil salinity and to investigate the influence of vegetation on soil salinity estimation. Digital bands of Landsat Thematic Mapper(TM) images, vegetation indices, and terrain indices were selected as predictive variables for the estimation. The generalized additive model(GAM) was used to analyze the quantitative relationship between soil salt content, spectral properties, and terrain indices. Akaike's information criterion(AIC) was used to select relevant predictive variables for fitted GAMs. A correlation analysis and root mean square error between predicted and observed soil salt contents were used to validate the fitted GAMs. A high ratio of explained deviance suggests that an integrated approach using spectral and terrain indices with GAM was practical and efficient for estimating soil salinity. The performance of the fitted GAMs varied with changes in vegetation cover.Salinity in sparsely vegetated areas was estimated better than in densely vegetated areas. Visible red and near-infrared bands, and the second and third components of the tasseled cap transformation were the most important spectral variables for the estimation. Variable combinations in the fitted GAMs and their contribution varied with changes in vegetation cover. The contribution of terrain indices was smaller than that of spectral indices, possibly due to the low spatial resolution of DEM. This research may provide some beneficial references for regional soil salinity estimation.

ESTIMATING MULTI-COUNTRY PROSPERITY INDEX: A TWO-DIMENSIONAL SINGULAR SPECTRUM ANALYSIS APPROACH

With the development of the global economy, interaction among different economic entities from one region is intensifying, which makes it significant to consider such interaction when constructing composite index for each country from one region. Recent advances in signal extraction and time series analysis have made such consideration feasible and practical. Singular spectrum analysis （SSA） is a well-developed technique for time series analysis and proven to be a powerful tool for signal extraction. The present study aims to introduce the usage of the SSA technique for multi-country business cycle analysis. The multivariate SSA （MSSA） is employed to construct a model-based composite index and the two dimensional SSA （2D-SSA） is employed to establish the multi-country composite index. Empirical results performed on Chinese economy demonstrate the accuracy and stability of MSSA-based composite index, and the 2D-SSA based composite indices for Asian countries confirm the efficiency of the technique in capturing the interaction among different countries.