青藏铁路对西藏旅游的影响分析

2006-07-01青藏铁路建成通车标志着西藏旅游将进入一个新时代。从探索西藏旅游发展动力机制模式出发,分析了青藏铁路对西藏旅游发展的影响,积极影响主要包括五个方面：1)高质量改善旅游可进入性,2)调整产业空间均衡发展,3)推动旅游产品创新发展,4)创建西藏旅游新形象,5)改善旅游发展宏观环境；同时指出青藏铁路通车对西藏旅游的“神秘”形象、产业要素的不配套和生态环境与历史文化保护带来三大挑战,无论从积极影响,还是带来的挑战均可以看出,青藏铁路对西藏旅游的影响将是跨越历史阶段的“革命性”影响。最后,提出了集聚发展、适度规模、政府主导和科学保护四大战略原则建议。     

基准面旋回与A/S比值的函数关系及地质意义

应用高分辨率层序地层学中的基准面旋回原理,对基准面变化进行了详细地分析。由于基准面的升降变化引起了可容纳空间与沉积物供给量的相对变化,相对应的可容纳空间变化率和沉积物供给率同时也发生变化,因而导致了在不同时期同一地区的地层在相序、保存程度和叠加样式上的差异,以及在同一时期内不同地区在相域上的差别。结合Cross提出的地层基准面原理以及沉积物供给量、可容纳空间变化率、沉积物供给率和沉积通量的物理属性,建立了相应的函数模型,推导说明了其函数关系式,阐述了它们之间的相互关系,总结了各自的变化规律和所代表的地质意义。本文的研究成果有助于进一步加深理解高分辨率地层层序的形成和演化,并且对于高分辨率地层层序的划分与对比,也有一定的借鉴意义。     

几种新型的航空重力测量系统和 航空重力梯度测量系统

较详细地描述了2个航空重力测量系统:一个系统由俄罗斯科学家设计、制造并进行飞行试验, 命名为GT-1A;另一个系统由加拿大山德尔地球物理公司研制, 命名为AIRGrav。这2个系统都利用惯性稳定平台, 适用于地质调查和普查油气和其他矿产。此外, 简略地评论了航空重力梯度测量系统, 如Falcon, AirFTG, GEDEX^TM和 ARKeX-EGG^TM。     

流动VLBI终端系统的技术改造与升级

本文介绍了流动VLBI终端系统的技术改造与升级情况以及MK5A数据系统的构成与工作原理，论述了实现BBC系统本振步长、BBC滤波器带宽和带宽增益补偿以及流动VLBI数据系统等方面的技术改造与升级的原理和方法，最后介绍了应用结果。     

对143年甘谷西7级地震史料的新见解

根据地震历史资料的考证分析,143年甘谷西地震可能由2次地震组成,其中陇西、汉阳(今甘谷)、武都三郡地震有感区为一次地震,称为南区;张掖、武威、北地(今吴忠)三郡地震有感区为另一次主震,称为北区。南区地震震中大致位于甘谷西,与原定震中位置大体相当,仍称为甘谷西地震,震级达714级左右,震中烈度约Ⅸ~Ⅹ度,发震构造为西秦岭北缘断裂带中段;北区的143年地震震中位于武威以东的腾格里沙漠边缘,震级达712级左右,震中烈度约Ⅹ度,推测其发震构造为祁连山-河西走廊活动断裂系东端的主干活动断裂之一。     

Molecular cloning and mRNA expression of cytochrome P4501A1 and 1A2 in the liver of common minke whales (Balaenoptera acutorostrata)

This study presents full-length cDNA sequences of CYP1A1 and 1A2, in common minke whale (Balaenoptera acutorostrata) from the North Pacific. Both CYP1A1 and CYP1A2 cDNAs had an open reading frame of 516 amino acid residues, and predicted molecular masses were 58.3 kDa and 58.1 kDa, respectively. The deduced full-length amino acid sequence of CYP1A1 revealed higher identities with those of sheep (86%) and pig (87%), and that of CYP1A2 was most closely related to human (82%) and monkey CYP1A2 (82%) among species from which CYP1A2 has been isolated so far. Differences in certain conserved and functional amino acid residues of CYP1A1 and 1A2 between common minke whale and other mammalian species indicate the possibility of their specific metabolic function. Concentrations of organochlorine compounds (OCs) including PCBs and DDTs analyzed in common minke whale liver showed no significant correlation with hepatic mRNA expression levels of CYP1A1 and CYP1A2, indicating no induction of these enzymes by such OCs.     

Further photometric observations of the X-ray binary A0535+26/V725 Tau: A new activity cycle

We performed new photoelectric U BV observations of the X-ray binary A0535+26 at the Crimean Station of the Sternberg Astronomical Institute in 1998–2003. After the brightness stabilized at a minimum of about 500 days in duration, a new brightness rise steeper than that observed previously began: the brightness increased over two seasons of observations by a total amplitude of \(0\mathop .\limits^m 5\). The physical parameters (T _e , n _e ) of the additional emission that caused this brightening match, within the error limits, were obtained from the averaged over 15 years, data, that include both the ascending and descending branches of the light curve. We found a delay of the variations in the Hα line relative to the continuum, which is no more than one year.     

3-D Non-linear Travel-time Tomography: Imaging High Contrast Velocity Anomalies

In this paper we present an approach for 3-D travel-time tomography, which works well in reconstructing high contrast velocity anomalies in both location and strength. It uses a revised ‘irregular’ approach to the shortest-path method as the ray tracer and a damped minimum norm, and constrained least-squares CG approach as the inversion solver. In ray tracing, the advantages of the revised ‘irregular’ over the ‘regular’ approach are that the secondary nodes introduced on the cell surfaces significantly improve accuracy of computed travel times, without dramatically increasing the total number of cells and nodes; the tri-linear velocity function defined across the cell guarantees accurate ray tracing in a high velocity contrast medium; and the capacity to calculate a relatively large 3-D model, due to the fast run speed (at least one order of magnitude over the ‘regular’ approach) and less number of total nodes. The introduction of ‘soft’ and ‘hard’ bounds into the inversion process changes the conditioning and makes the solution meaningful in a physical sense. Thus the artifacts caused by noise and high velocity contrasts are substantially suppressed and the image quality is considerably improved, making the solution realistic with noisy or inconsistent travel-time data. Several numerical tests indicate that we can obtain good quality images even for high velocity contrast anomalies (say more than 20%) in the target region. This means the inversion algorithm is an efficient and effective procedure. Meanwhile, the inversion procedure is not very sensitive to the quality of the travel-time data, which is promising for practical usage.     

高速USB控制器的应用

阐述了USB2.0高速总线的工作原理,并运用Cypress公司推出的USB2.0控制器CY7C68013芯片加上高速A/D转换芯片实现了高速A/D采样,为今后的USB高速应用打下了基础.     

Dust formation in primordial Type II supernovae

We have investigated the formation of dust in the ejecta of Type II supernovae (SNe), mostly of primordial composition, to answer the question of where the first solid particles are formed in the Universe. However, we have also considered non-zero progenitor metallicity values up to Z = Z_⊙ . The calculations are based on standard nucleation theory, and the scheme has been tested for the first time on the well-studied case of SN1987A, yielding results that are in agreement with the available data. We find that: (i) the first dust grains are predominantly made of silicates, amorphous carbon (AC), magnetite and corundum; and (ii) the largest grains are the AC ones, with sizes around 300 Å, whereas the other grain types have smaller radii, around 10–20 Å . The grain size distribution depends somewhat on the thermodynamics of the ejecta expansion, and variations in the results by a factor ≈2 might occur within reasonable estimates of the relevant parameters. Also, and for the same reason, the grain size distribution is essentially unaffected by metallicity changes. The predictions on the amount of dust formed are very robust: for Z =0 , we find that SNe with masses in the range (12–35) M_⊙ produce about 0.08 M_⊙≲ M _d≲0.3 M_⊙ of dust per supernova. The above range increases by roughly three times as the metallicity is increased to solar values. We discuss the implications and the cosmological consequences of the results.