On the optical variability of a be star,HDE 245770, — the optical counterpart of the transient X-ray pulsar A0535+26

Photoelectric WBVR observations of Be star HDE 245770=V 725 Tau, the optical counterpart of the transient X-ray pulsar A0535+26, having a pulse period of about 104 s, were conducted for more than 10 years. An irregular long-term optical variability of the star with amplitudes of the order of a few tenths of magnitude was found to be a usual phenomenon. In some cases rapid changes of the star's optical luminosity with a characteristic period of a few tens of minutes or a few hours, and an amplitude of several hundredths of magnitude in all the spectral bands used, which have practically coincided or correlated with the X-ray pulsar outbursts detected by X-ray satellites, were observed.Photoelectric recording of the optical flux from HDE 245770 were made in 1981–1982 with a time resolution of 1 second and 10 s, respectively, in theR spectral band (₀ 7000 Å) and in the narrowH -emission-line band (_1/2 75 Å) using a 48-cm reflector of High-Mountain Tien-Shan observatory of the Sternberg Astronomical Institute near Alma-Ata. An analysis of autocorrelation functions of the flux changes from object under study and a comparison with the star BD+26° 876 indicated the variability of luminosity of V 725 Tau in theR spectral band on a time scale of a few tens of second; this variability resembles shot noise with a characteristic time of stochastic bursts of about 15–20 s and their amplitudes of about a few tenths of a percent. InH -emission-line radiation autocorrelation functions and power spectra show quasiperiodic variability of luminosity of HDE 245770 with a characteristic period of about 100–150 s and an amplitude in the neighbour-hood of 0.5%. The latter result is not quite reliable because of not quite fine weather conditions during the observations; independent observations and check-up are required.     

太阳黑子数及Ap指数周期变化特征的小波分析

应用Morlet小波变换方法从多个变化尺度上对1932—2000年的太阳黑子数及Ap指数的变化特征进行分析．(1)太阳黑子数存在准11年、准32年的周期变化特征及Ap指数存在准32年、准11年、准6个月、准27天和准13．9天的周期变化特征；(2)太阳黑子数及Ap指数有着相似的准11年周期变化，但Ap指数极值的出现要比太阳黑子数极值出现滞后1—2年；(3)Ap指数准27天的周期变化在太阳黑子活动高、低年不同，在太阳活动低年，Ap指数有着较稳定的准27天周期变化，但在太阳活动高年，27天的周期变化几乎消失，这种周期变化的消失和出现时间可在Morlet小波变换图中体现出来。     

工艺资源负荷指数的估算方法研究

针对工艺资源的负荷均衡和资源利用情况,研究了工艺资源负荷问题,分析了工艺资源结构,建立了工艺资源信息模型,并给出了基于经验的工艺资源定额估算方法,建立了工艺资源负荷指数模型。算例证实了该模型的有效性。     

先进客机设计中油耗指标的分解方法

先进客机最重要指标之一是油耗指标。研究一种将油耗指标进一步分解为更为具体的发动机的耗油率指标、客机的升阻比指标和使用空重指标的方法。以典型中程客机为例，应用分段解析方法建立客机飞行剖面的燃油量计算程序。应用计算程序分别分析了发动机的耗油率、客机的升阻比和使用空重的变化对油耗的影响。在此基础上，对发动机的耗油率、客机的升阻比和使用空重的指标进行规划，以满足先进客机油耗指标的要求。研究结果为未来客机确定出合理的升阻比、耗油率和使用空重的指标提供了参考。     

Is the North Atlantic Oscillation modulated by solar and lunar cycles? Some evidences from Hurst autocorrelation analysis

Several studies have suggested that the Sun and Moon cycles affect the Earth climatic dynamics. Nevertheless, there is a long-standing controversy whether solar variability and tides can significantly generate climate change, and how this may occur. Spectral analysis of climatic indices has provided only indirect evidences of the effects of solar–tidal periodicities in the Earth climate. This work addresses the issue by considering the dynamics of the daily North Atlantic Oscillation index over the period from 1950 to 2009. In contrast to previous studies, this work proposes that external cycles can be detected in the autocorrelation dynamics rather than in the raw North Atlantic Oscillation index series. Here, the R/S-scaling analysis is used to quantify, via the so-called Hurst exponent, the presence of autocorrelations along the studied years. Fourier analysis scan of the autocorrelation series thus show two prominent spectral components near (±3%) the lunar tidal 4.425 and the solar 11 years cycles. Intermediate spectral components near 6.4, 7.75 and 8.9 years are proposed to be, at least partially, a result of energy capture from internal mechanisms into cycles resulting from the nonlinear resonance of the fundamental solar–tidal cycles. The dominant effect of the solar variability is clarified by showing that in about 70% of the studied period the sunspot number and the Hurst exponent phases are synchronized, indicating that a higher solar activity enhances the North Atlantic Oscillation index predictability.     

Semi-automatic determination of the Azores Current axis using satellite altimetry: Application to the study of the current variability during 1995–2006

Satellite altimetry has been widely used to study the variability of the ocean currents such as the Azores Current (AzC) in the North Atlantic. Most analyses are performed over the region that encloses the current, thus being somehow affected by other oceanographic signals, e.g., eddies. In this study, a new approach for extracting the axis of a zonal current solely based on satellite altimetry is presented. This is a semi-automatic procedure that searches for the maximum values of the gradient of absolute dynamic topography (ADT), using the geostrophic velocity as auxiliary information. The advantage of this approach is to allow the analyses to be performed over a buffer centered on the current axis instead of using a wider region. It is here applied to the AzC for the period June 1995–October 2006.     

Regional and temporal variability of solar activity and galactic cosmic ray effects on the lower atmosphere circulation

In this work we studied the spatial and temporal structure of long-term effects of solar activity (SA) and galactic cosmic ray (GCR) variations on the lower atmosphere circulation as well as possible reasons for the peculiarities of this structure. The study revealed a strong latitudinal and regional dependence of SA/GCR effects on pressure variations in the lower troposphere which seems to be determined by specific features of baric systems formed in different regions. The temporal structure of SA/GCR effects on the troposphere circulation at high and middle latitudes is characterized by a roughly 60-year periodicity which is apparently due to the epochs of the large-scale atmospheric circulation. It is suggested that a possible mechanism of long-term effects of solar activity and cosmic ray variations on the troposphere circulation involves changes in the evolution of the polar vortex in the stratosphere of high latitudes, as well as planetary frontal zones.     

Active region properties and irradiance variations

Total Solar Irradiance (TSI) has been measured for more than three decades. These observations demonstrate that total irradiance changes on time scales ranging from minutes to years and decades. Considerable efforts have been made to understand the physical origin of irradiance variations and to model the observed changes using measures of sunspots and faculae. In this paper, we study the short-term variations in TSI during the declining portion and minimum of solar cycle 22 and the rising portion of cycle 23 (1993–1998). This time interval of low solar activity allows us to study the effect of individual sunspot groups on TSI in detail. In this paper, we indicate that the effect of sunspot groups on total irradiance may depend on their type in the Zürich classification system and/or their evolution, and on their magnetic configuration. Some uncertainties in the data and other effects are also discussed.     

基于改进的PRI方法对植被冠层叶绿素含量的反演

叶绿素是植被光合作用的重要色素，对植被的健康状况有直接的指示作用。利用遥感技术准确、快速地获取植被叶绿素含量对精准农业具有重要意义。文章在对各种光化学植被指数（Photochemical Reflectance Index，PRI）与叶绿素含量进行敏感性分析的基础上，提取出对叶绿素变化较为敏感的组合形式，并考虑土壤背景的影响，提出了一种改进的PRI模型，同时利用在小汤山试验田获取的地面采样数据和实用模块化成像光谱仪（Operative Modular Imaging Spectrometer，OMIS）数据进行验证。结果表明，基于OMIS高光谱数据，模型能够很好地对植被冠层的叶绿素含量进行反演，反演的叶绿素含量与实测值具有较好的相关性。     

Aircraft air conditioning system health state estimation and prediction for predictive maintenance

The vast potential of system health monitoring and condition based maintenance on modern commercial aircraft is being realized through the innovative use of Airplane Condition Monitoring System (ACMS) data. However there are few methods addressing the issues of failure prognostics and predictive maintenance for commercial aircraft Air Conditioning System (ACS). This study developed a Bayesian failure prognostics approach using ACMS data for predictive maintenance of ACS. First, a health index characterizing the ACS health state is inferred from a multiple sensor signals using a data driven method. Then a dynamic linear model is proposed to describe the degradation process for failure prognostics. Bayesian inference formulas are carried out for degradation estimation and prediction. The developed approach is applied on a passenger aircraft fleet with ACMS data recorded for one year. The analysis of the case study shows that the developed method can produce satisfactory prognostics results, where all the ACS failure precursors are identified in advance, and the relative errors for the failure time prediction made when just entering the degradation warning stage are less than 8%. This would allow operators to proactively plan future maintenance.