DSQ型短基线水管倾斜仪及标定装置的研制

阐述了具有国产化、小型化、数字化、智能化特点的DSQ型短基线水管仪的原理、结构与性能指标 ,并介绍了该仪器在 7个试验台 8条短基线上的试验与监测记录、精度估算结果。在全国 30多个台站与朝鲜平壤大成山地震台的推广证明 :该仪器在小于或等于 5m的洞体基线上均能取得清晰、光滑、令人满意的倾斜固体潮汐观测结果 ,成功率达 10 0 % ,精度达当今国际同类先进水平。     

Secular perturbation theory and computation of asteroid proper elements

A new theory for the calculation of proper elements, taking into account terms of degree four in the eccentricities and inclinations, and also terms of order two in the mass of Jupiter, has been derived and programmed in a self contained code. It has many advantages with respect to the previous ones. Being fully analytical, it defines an explicit algorithm applicable to any chosen set of orbits. Unlike first order theories, it takes into account the effect of shallow resonances upon the secular frequencies; this effect is quite substantial, e.g. for Themis. Short periodic effects are corrected for by a rigorous procedure. Unlike linear theories, it accounts for the effects of higher degree terms and can thus be applied to asteroids with low to moderate eccentricity and inclination; secular resonances resulting from the combination of up to four secular frequencies can be accounted for. The new theory is self checking : the proper elements being computed with an iterative algorithm, the behaviour of the iteration can be used to define a quality code. The amount of computation required for a single set of osculating elements, although not negligible, is such that the method can be systematically applied on long lists of osculating orbital elements, taken either from catalogues of observed objects or from the output of orbit computations. As a result, this theory has been used to derive proper elements for 4100 numbered asteroids, and to test the accuracy by means of numerical integrations. These results are discussed both from a quantitative point of view, to derive an a posteriori accuracy of the proper elements sets, and from a qualitative one, by comparison with the higher degree secular resonance theory.     

Development of a new photon diffraction imaging system for diagnostic nuclear medicine

The objective of this project is to develop and construct an innovative imaging system for nuclear medicine and molecular imaging that uses photon diffraction and is capable of generating 1–2 mm spatial resolution images in two or three dimensions. The proposed imaging system would be capable of detecting radiopharmaceuticals that emit 100–200 keV gamma rays which are typically used in diagnostic nuclear medicine and in molecular imaging. The system is expected to be optimized for the 140.6 keV gamma ray from a Tc-99m source, which is frequently used in nuclear medicine. This new system will focus the incoming gamma rays in a manner analogous to a magnifying glass focusing sunlight into a small focal point on a detector's sensitive area. Focusing gamma rays through photon diffraction has already been demonstrated with the construction of a diffraction lens telescope for astrophysics and a scaled-down lens for medical imaging, both developed at Argonne National Laboratory (ANL). In addition, spatial resolutions of 3 mm have been achieved with a prototype medical lens. The proposed imaging system would be comprised of an array of photon diffraction lenses tuned to diffract a specific gamma ray energy (within 100–200 keV) emitted by a common source. The properties of photon diffraction make it possible to diffract only one specific gamma ray energy at a time, which significantly reduces scattering background. The system should be sufficiently sensitive to the detection of small concentrations of radioactivity that can reveal potential tumor sites at their initial stages of development. Moreover, the system's sensitivity would eliminate the need for re-injecting a patient with more radiopharmaceutical if this patient underwent a prior nuclear imaging scan. Detection of a tumor site at its inception could allow for an earlier initiation of treatment and wider treatment options, which can potentially improve the chances for cure.     

Large-scale inhomogeneities and the cosmological principle

The compatibility of cosmologic principles and possible large-scale inhomogeneities of the Universe is discussed. It seems that the strongest symmetry principle compatible with reasonable inhomogeneities is full conformal symmetry in the three-space defined by the cosmological velocity field; but even then the standard model is isolated from inhomogeneous ones when the whole evolution is considered.     

An investigation of wind-driven topographically controlled motions in the Northern Adriatic

The present paper describes a three-dimensional hydrodynamical numerical model of the Northern Adriatic. The model is based on the approach of N.S. Heaps in which the integral transformations are used to reproduce the vertical distribution of velocity. The model is applied to reproduce the wind-induced motion in the Northern Adriatic during winter. Hydrographic, sea level and current data collected during the MEDALPEX are used to verify the model predictions. Analysis of the empirical data suggests that the bura wind induces the most pronounced, although transient, contribution to the Northern Adriatic current field. The model predictions clearly show the controlling influence of a shallower bottom along the Italian coast. The model to data comparison suggests for the eddy viscosity coefficient value an order of magnitude lower than expected from literature data. The quadratic law for bottom friction and wind-stress curl have been identified as possible improvements of the model.     

Development of GIS as a tool in the Ministry of Mining and Energy,Serbia

On behalf of the Serbian Government, the Ministries of Mining and Energy and of Science and Environment Protection are signatories to a master plan for the promotion of the mining industry in Serbia. This is being achieved with the assistance of the Japanese Government through the Japanese International Cooperation Agency (JICA), who engaged a mining company from Tokyo–Mindeco (Mitsui Mineral Development Engineering Co. Ltd) to partner the Serbian ministries, the Mining and Geology Faculty in Belgrade, the Geological Institute of Serbia (Belgrade), the Copper Institute (Bor), and the Military Geographical Institute (Belgrade), as well as private companies dealing in geological exploration, etc. Apart from other things, the master plan contains a newly‐formed GIS application, which registers exploration, exploitation fields and other relevant data. This GIS web application was one the first steps towards the realization of ‘e‐Government’ in the field of geological exploration and mining activities within the Republic of Serbia.     

Relationships among predatory fish, sea urchins and barrens in Mediterranean rocky reefs across a latitudinal gradient

Previous studies conducted on a local scale emphasised the potential of trophic cascades in Mediterranean rocky reefs (involving predatory fish, sea urchins and macroalgae) in affecting the transition between benthic communities dominated by erected macroalgae and barrens (i.e., bare rock with partial cover of encrusting algae). Distribution patterns of fish predators of sea urchins (Diplodus sargus sargus, Diplodus vulgaris, Coris julis and Thalassoma pavo), sea urchins (Paracentrotus lividus and Arbacia lixula) and barrens, and fish predation rates upon sea urchins, were assessed in shallow (3-6m depth) sublittoral rocky reefs in the northern, central and southern sectors of the eastern Adriatic Sea, i.e., on a large spatial scale of hundreds of kilometres. No dramatic differences were observed in predatory fish density across latitude, except for a lower density of small D. sargus sargus in the northern Adriatic and an increasing density of T. pavo from north to south. P. lividus did not show any significant difference across latitude, whereas A. lixula was more abundant in the southern than in the central Adriatic. Barrens were more extended in the southern than in the central and northern sectors, and were related with sea urchin density. Fish predation upon adult sea urchins did not change on a large scale, whereas it was slightly higher in the southern sector for juveniles when predation rates of both urchins were pooled. Results show that: (1) assemblages of predatory fish and sea urchins, and barren extent change across latitude in the eastern Adriatic Sea, (2) the weak relations between predatory fish density and predation rates on urchins reveal that factors other than top-down control can be important over large scale (with the caveat that the study was conducted in fished areas) and (3) patterns of interaction among strongly interacting taxa could change on large spatial scales and the number of species involved.     

从腾冲和香格里拉沉积记录看60ka BP以来的印度季风活动特征

通过腾冲北海与香格里拉纳帕海有机碳含量、δ13C、粒度等沉积指标和若干孢粉指标的对比,参照60ka BP以来孟加拉湾的沉积韵律互层与δ18O记录,发现它们同与印度季风系统存在密切关联。然而由于经纬与海陆分布的差异,夏季风和冬季风对各处的影响亦有很大差别。大约发生于37~32ka BP的强大的暖湿型气候事件在北海与纳帕海盆地的沉积序列之中反映突出,成为过去60ka间最引人瞩目的现象,但是却缺乏海域记录的有力呼应。海陆记录对比结果表明,MIS3后期区域气候事件的控制因素来自陆地而非海洋,青藏高原在此期间的特别升温导致印度冬季风的衰退及其他大气环流型式的改变有可能是重大气候事件形成的主因。此外,陆地地貌对于季风的降水效应也有不可忽视的影响。