Classical Cepheids and the Distances of HST Program Galaxies

The distances of HST program galaxies are revised using the PL-relations we have obtained previously along with a different method from that employed by Freedman et al. On the average, the resulting distances to these galaxies have higher internal accuracies than those obtained before by others. In addition, we have used no corrections for metallicity or for the incompleteness of the samples of classical cepheids in deriving these distances. Despite this, our distance moduli, with a dispersion of ±0^m.395, agree with those of Freedman et al. This indicates that these two effects have little or even no effect for the samples of classical cepheids in the HST program galaxies.     

The relative importance of chlorophyll,dissolved and particulate material,and seawater to the vertical extinction of light

The attenuation of light by chlorophyll, particulate and dissolved material, and seawater off the coast of north-west Africa showed distinct cross-shelf variations. Attenuation was most rapid nearshore because of absorption by non-biological particles. This particulate matter was probably aeolian material from the nearby Sahara Desert of resuspended sand from the sediment. Regardless of the source, the marked light extinction resulted in decreased phytoplankton growth nearshore. Light attenuation characteristics of the region were anomalous when compared to those of other ocenic regimes.     

Influence of precambrian basement on the chemical composition of Mesozoic granitoid rocks in northeastern Asia

A hypothesis for effects of stable tectonic elements on chemical composition of Mesozoic granitoids in northeastern Asia is tested. Chemical compositional change of granitoid rocks is examined in nine-dimensional space of rock-forming oxides. Stable geologic structures of the region are outlined by trends of Euclidean distances between rock recognized as a standard in a space of major rock-forming oxides and composition of individual samples. A data-smoothing polynomial of the fourth order corresponds closely to the geology of the region. Chemically stable masses of quartz diorite are thought to be delivered directly from magmatic sources along deep faults. A great variety of acidic granites, which occupy for each analysis separate cells in the nine-dimensional classification, are presumed to be palingenetic in origin.     

The radio emission from Sakurai's Object (beyond 1 mm)

Observations of V4334 Sgr have been made with the JCMT, MERLIN, ATCAand the VLA. Searches with JCMT for CO in and around the PNassociated with V4334 Sgr has provided upper limits for the peakemission of 20 mK and the line-flux of 0.17 K-km s^-1. Thisgives an upper limit on the CO mass of 3 × 10^-7D² M at D kpc. VLA observations havedetected 2.7 ± 0.1 mJy of emission from the PN, which appears to beclumpy and extends to a radius of 17 arcsec. This indicates anoptically thick nebula, and suggests a range of distances of 1.83 to4.96 kpc for a reasonable range of masses for optically thick PN.Comparison with estimated total H emission gives E(B-V) =0.8 ±0.1. MERLIN observations do not detect the wind indicated tobe present in IR observations prior to dust obscuration. TheAustralia Telescope Compact Array did not detect OH maser emissionfrom either the main- or satellite-lines. Future VLA observationswill increase integration times and uv-coverage to significantlyimprove the radio imaging. MERLIN target-of-opportunity time isretained in order to attempt to image any fast wind as it develops.An independent estimate of the PN mass would allow the use of theradio observations to determine the distance; conversely anindependent distance measurement would lead to a PN mass estimate.The author urges the acquisition of an accurate measurement of thetotal H emission from the PN.     

Ground motion prediction with the empirical Green's function technique: an assessment of uncertainties and confidence level

An assessment of uncertainties for ground motion predictions with the aid of the empirical Green's function (EGF) technique is presented. The main input parameters were identified, and their respective uncertainties were assessed by means of an international expert inquiry. The repercussion of these input uncertainties on the final ground motion estimates were investigated by means of the Latin Hypercube Sampling technique. The mean ground motion estimates (response spectra) and their standard deviations were compared with results obtained from empirical attenuation laws. The most sensitive input parameter turned out to be the seismic moment corresponding to the EGF. In general, if the source parameters are well determined, equivalent uncertainties, statistically speaking, can be expected from the EGF technique and from the application of attenuation laws. Therefore, if EGFs with well known source parameters are available, the EGF technique seems to be preferable: site effects are automatically taken into account, and physically realistic acceleration time histories can be obtained. However, further investigations on the reliability of the EGF technique should be performed, and finally, it is recalled that the EGF technique is based on the assumption of linearity. If conditions are such that this assumption cannot be maintained, the EGF technique should be combined with non-linear geotechnical methods.     

三角高程测量中天顶和斜距的计算

本文通过分析大气密度与大气垂直折光系数的关系 ,推导出消除了大气垂直折光影响的天顶距和斜距计算公式 ,既拓宽了天顶距的适用范围 ,又提高了三角高程测量成果精度。     

光电测深和激光投点技术在矿井联系测量中的试验研究

介绍了光电测距仪直接在井筒中测定井深导入高程和激光投点代替钢丝投点的试验研究,并和传统方法进行比较,结果令人十分满意。     

地震资料处理中的聚束滤波方法

聚束滤波方法的基本原理,包括信号与噪音模型、设计准则和所获得的聚束滤波器．本文所用的自适应聚束滤波器是根据具有参数化的动校正量、振幅及相位随偏移距变化（ＭＶＯ、ＡＶＯ及ＰＶＯ）的一次反射和多次反射信号模型而设计的．但在实际应用中ＰＶＯ通常不能得到证实．结果分析能为进一步的从ＡＶＯ及ＰＶＯ获取岩石类型信息的专题研究提供资料．人工合成资料的例子给出了参数化的自适应聚束滤波的实施细节和所设计滤波器的响应特性．实际资料的例子表明数据自适应聚束滤波在叠前共中点道集地震多次波消除上比Ｒａｄｏｎ变换方法更灵活、有效．类似于其它叠前处理过程,自适应聚束滤波的优越性在信噪比较高的资料上体现得最为明显．