Regular and Chaotic Solutions of the Sitnikov Problem near the 3/2 Commensurability

Regular solutions at the 3/2 commensurability are investigated forSitnikovx234364u/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0">s problem. Utilizing a rotating coordinate system and theaveraging method, approximate analytical equations are obtained for thePoincare sections by means of Jacobian elliptic functions and 3x234364u/xxlarge960.gif" alt="pgr" align="BASELINE" BORDER="0">periodicsolutions are generated explicitly. It is revealed that the system exhibitsheteroclinic orbits to saddle points. It is also shown that chaotic regionemerging from the destroyed invariant tori, can easily be seen for certaineccentricities. The procedure of the current study provides reliable answersfor the long-time behavior of the system near resonances.     

波谱曲线指数化的方法和意义

地质研究对象的各种波谱曲线和数据包括显示量（由曲线的高低位置反映的总体辐射强度）和质（由曲线内部的起伏结构反映的不同波段辐射强度的内在相互关系）两方面的特征，其总体辐射强度往往因各种观测因素和条件的不同而发生变化，但其曲线结构形式一般不会因此而改变，本文一般性地介绍一种将复杂的原始波谱曲线简简单指数的思路和方法，使各种波谱曲线所反映的物体内在本质特征是以加强突出，同时尽量弱化总体辐射强度这一易变的     

天池天文峰剖面全新世火山喷发物长石的结构特征及意义

利用扫描电镜和x射线衍射分析数据研究天池火山天文峰剖面全新世喷发物中的长石表面特征和结构状态,结果显示:天文峰剖面从顶部黑色浮岩向下到暗灰色浮岩中,长石表面比较新鲜,个别长石有极轻微风化,在长石颗粒表面凹处偶有沉积厚度不同的非晶质絮状物。长石为碱性长石中的高透长石-高钠长石系列,特征衍射峰的强度、面网d值与歪长石PDF数据基本相符,物相组成为(Or37～41,Ab63～59),表明天池火山喷发物中的长石属歪长石;长石有序度介于0.045～0.089之间;η参数介于-1.010～-1.361之间;最低结晶温度为800～990℃,且顶部黑色浮岩中长石的最低结晶温度高达990℃。研究认为,有天池火山喷发的年代越新,长石有序度越低,其结构状态所记录的温度越高的趋势。目前测得的天池火山长石结构是由高温结构随温度下降转变而来,因此天池火山长石最初形成的温度可能更高。天池火山全新世喷发物中长石结构状态特征的差异可能与火山喷发的年代、喷发温度有关。研究天池火山全新世喷发物中的长石结构状态特征具有一定的理论和实际应用价值     

Magnetic field measurements on four yellow supergiants. I

Multiyear high precision measurements of the longitudinal component of the magnetic field (B_e) of four supergiants are reported: x73/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">Aqr (G0 Ib), x73/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">Aqr (G2 Ib), x73/xxlarge603.gif" alt="epsiv" align="BASELINE" BORDER="0">Gem (G8 Ib), and x73/xxlarge603.gif" alt="epsiv" align="BASELINE" BORDER="0">Peg (K2 Ib). The best measurement accuracy, x73/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">=0.8 G, was achieved for x73/xxlarge603.gif" alt="epsiv" align="BASELINE" BORDER="0">Peg. A Monte Carlo method was used to test the reliability of the derived measurement errors. The differences between the observational errors and the calculated Monte Carlo errors were x73/xxlarge8764.gif" alt="sim" align="MIDDLE" BORDER="0">3.2%. For x73/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">Aqr and x73/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">Aqr no statistically significant value of the magnetic field was recorded when averaged over a night. For eGem the following overnight average values of the magnetic field were recorded on five nights: 11.1±2.7 G, 9.8±2.5 G, –10.5±3.0 G, 38.1±7.4 G, and 5.3±1.5 G. For x73/xxlarge603.gif" alt="epsiv" align="BASELINE" BORDER="0">Peg the magnetic field recorded over two nights was –5.3±0.9 G and – 2.7±0.8 G.Translated from Astrofizika, Vol. 48, No. 1, pp. 15–28 (February 2005).     

Cenozoic Intraplate Alkaline Volcanism of Western Bohemia

Three independent volcanic suites have been recognised in W Bohemia: (i) the old unimodal alkaline ol. nephelinite-tephrite (29-19 Ma) in the Ohx157u28370153654/xxlarge345.gif" alt="rcaron" align="BASELINE" BORDER="0">e Rift, (ii) two contemporaneous weakly (trachybasalt/trachyandesite-trachyte/rhyolite; 13-11 Ma) and strongly (ol. nephelinite-tephrite/basanite; 12-8 Ma) alkaline series in the flank of the Cheb-Domax157u28370153654/xxlarge382.gif" alt="zcaron" align="BASELINE" BORDER="0">lice Graben formed by the Teplá Highland and (iii) the young unimodal ol. melilitite/ol. nephelinite alkaline suite (2.0-0.12 Ma) at the intersection of the above mentioned structures in the Cheb Basin. The magmas of all the suites are mantle-derived and, in the case of the Cheb-Domax157u28370153654/xxlarge382.gif" alt="zcaron" align="BASELINE" BORDER="0">lice Graben series, associated with the AFC process. Two main fault systems: (i) ENE-WSW and (ii) NNW-SSE are developed in W Bohemia, corresponding to the directions of the two prominent taphrogenic structures. The southwesterly continuation of the Ohx157u28370153654/xxlarge345.gif" alt="rcaron" align="BASELINE" BORDER="0">e Rift across the Mariánské Láznx157u28370153654/xxlarge283.gif" alt="ecaron" align="BASELINE" BORDER="0"> Fault is marked by volcanics only.     

Water use by intensively cultivated willow using estimated stomatal parameter values

Large land areas in Sweden are planned to be planted with high producing, short rotation forest stands of willow in the beginning of the 1990s. Since willow is a highly hydrophilic species, this new land use may have strong implications on water resources. To assess these implications, evaporation of Salix viminalis and Salix viminalis x caprea stands in lysimeters was analysed with the simple, yet physically realistic KAUSHA model. Parameter values for the Lohammar equation were deduced (b = 100 m³ kg^?1, k_max = 0.01 m s^?1), believed to be applicable to other sites. Simulated evaporation during the 1980 growth season for a normal stand with a production of 12 tonnes of dry matter per hectare per season was 526 mm, of which 375 mm was transpiration, 56 mm interception evaporation, and 95 mm soil evaporation. For an optimally irrigated 20-tonnes stand, the total evaporation was 584 mm, of which 430 mm was transpiration. As a comparison, Penman open water evaporation was 430 mm. To avoid soil water stress in the 20-tonnes stand, 140 mm was needed as irrigation, equivalent to 25 per cent of the mean annual precipitation. Since intensively cultivated willow plantations seemed to be using much water, it was concluded that introduction of this agri-forestry practice must be carefully planned to make use of this property, e.g. in biological filters or in reclaiming water-logged land.     

Sub-sampling unconsolidated sediments: A solution for the preparation of undistrubed thin-sections from clay‐rich sediments

Using the principles of electrox36mk51x55x/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">osmosis, a subx36mk51x55x/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">sampling technique for clay-rich sediments is introduced that produces undisturbed thinx36mk51x55x/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">sections from sediment cores. The fragile sample remains in the same disposable box throughout the process, preventing collapse of its structure during subx36mk51x55x/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">sampling, manipulation and impregnation, as well as other potential problems.     

GNSS/INS组合导航系统中异常观测的探测与抑制

在隧道、城市峡谷、多径效应明显等恶劣环境中,GNSS定位结果易受异常值影响。GNSS异常值的存在使得观测噪声服从Gauss分布的假设不再成立,从而将严重影响GNSS/INS组合系统中Kalman滤波的性能。本文将抗差Kalman滤波用于GNSS/INS组合导航系统中异常观测的探测与抑制。根据设定的显著性水平对Kalman滤波的新息向量进行c2检验,原假设被拒绝时认为异常观测存在;然后引入尺度化因子对新息向量的协方差矩阵进行膨胀,以抑制异常观测对滤波结果的影响,并通过解析方法求解该因子。数值仿真的结果验证了算法的有效性。