冲击反循环工程钻机自动同步机构的原理

采用行星齿轮差速机构作为ＧＣＦ－１５００型冲击反循环工程钻机的自动同步机构，已经获得成功。分析了该机构的运动学原理和力平衡原理。该机构具有结构简单、工作可不的特点。     

浙江暴雨过程的中尺度低压

本文应用带通滤波法分析浙江暴雨过程中的中尺度天气系统。结果表明:(1)分析的五次暴雨过程都与中尺度地面低压有密切联系;(2)中低压是暖性的,有一较强的中尺度水汽辐合中心与它相伴,位于它的北部或东部;(3)暴雨的发生与水汽辐合中心密切相关,暴雨的地点、雨强和水汽辐合中心的位置、强度相对应;(4)地面中低压的发展与300hPa上发散流场和辐散中心的出现,以及对流层内非热成风涡度和上升运动的发展等环境条件有密切关系。     

THE INFLUENCE OF HORIZONTALLY NON-UNIFORM HEATING UPON THE DEVELOPMENT OF STRONG CONVECTIVE MESOSCALE DISTURBANCES

It is shown by observational data and synoptic analysis that the development of strong convective echo is influenced by the horizontally non-uniform heating, such as the one caused by lake-land distribution. In this paper, a simple linear cell-convection model is established using an appropriate heating field, and the instability of heating convection is theoretically studied. It is found that the heating convection development will be unstable if the heating-caused temperature gradient dT0/dy is greater than the critical value (dT0/dy)c which is approximately 0.64℃/10 km, and that the development of convective band has a preferred width of 12.5 km. It will take 25 min for the initial disturbance to increase intensity by 10 times. All these results are in rather good agreement with the squall line process in the lake-land region of Jiangsu Province on June 8, 1979.     

浙江冰雹天气与边界层辐合的关系

通过七次冰雹天气过程的分析,发现浙江地区大范围降雹过程之前,对流层中下层并不一定有大尺度辐合和上升运动,而是与边界层辐合却有着十分密切的关系.降雹前,边界层中都有辐合线存在,与此相应,有较强的质量和水汽通量辐合.无辐合线,则无大范围的冰雹天气发生.冰雹区的水汽通量散度垂直分布有明显特点,水汽辐合多集中于边界层内,辐合最大值在950百帕附近,850百帕以上辐合很小,甚至是辐散.还发现边界层辐合的强度与冷锋位置有关.     

The influence of horizontally non-uniform heating upon the development of strong convective mesoscale disturbances

It is shown by observational data and synoptic analysis that the development of strong convective echo is influenced by the horizontally non-uniform heating, such as the one caused by lake-land distribution. In this paper, a simple linear cell-convection model is established using an appropriate heating field, and the instability of heating convection is theoretically studied. It is found that the heating convection development will be unstable if the heating-caused temperature gradientdT ₀/dy is greater than the critical value (dT ₀/dy) _c which is approximately 0.64°C/10 km, and that the development of convective band has a preferred width of 12.5 km. It will take 25 min for the initial disturbance to increase intensity by 10 times. All these results are in rather good agreement with the squall line process in the lake-land region of Jiangsu Province on June 8, 1979.     

The origin of basaltic rocks in Niutoushan area— high pressure differentiation

The Niutoushan basaltic cone, consisting of subalkali (quartz-tholeiite and olivine-tholeiite) and alkali basalts, is Late Tertiary in age. Its major characteristics are generalized as follows:

1. Both early subalkali and late alkali bali basalts are formed under the same geological environment.
2. The continuity in chemical composition from subalkali to alkali and the low FeO/MgO in alkali basalts show that they are the products of cognate magmatic differentiation.
3. The change from low REE abundance and weak enrichment of LREE in subalkali to high REE abundance and strong enrichment of LREE in alkali basalts indicates obvious REE enrichment and fractionation during magmatic differentiation. Weak positive Eu anomalies in the REE patterns are indicative of their formation under low oxygen fugacity conditions.
4. According to the calculated values, 70–75% of the primary olivine tholeiitic magma had been separated as subalkaline basaltic magma, the rest residual magma became alkaline basaltic magma. This result is consistent to the field observation that the outcrop area of subalkali basalts is four times as much as that of alkali basalts.
5. The basaltic rocks of Niutoushan show an S-type distribution straddling the thermal barrier on Ol′-Ne′-Qu′ diagram and an evolution tendency for Ne to increase with increasing FeO/MgO. This is in agreement with the melting experimental data on olivine basalts at 10–20 kb.
6. Mantle-derived inclusions (spinel lherzolite) in this area occur in both alkali olivine basalts and olivine tholeiites. The latter is of extremely rare occurrence. The formation temperature and pressure of the inclusions in alkalibasalts and olivine tholeiites have been calculated. The results show that the alkaline basaltic magma was separated from the subalkaline basaltic magma at about 20 kb.

Basaltic rocks in Niutoushan were formed through the so-called “high pressure differentiation”, that is, at about 20 kb the crystallization of clinopyroxene and orthpyroxene resulted in the separation of subalkaline basaltic magma from the primary olivine tholeiitic magma, and then the residue gradually became alkaline olivine basaltic magma.     

Fuzzy cluster analysis in geochemical exploration

As a classification method, cluster analysis has been widely used in geology and geochemical exploration, but sometimes the results of clustering were difficult to interpret, or missclassification of geochemically similar members into entirely different clusters might occur. The reason for this is suggested and discussed. A new technique, fuzzy clustering is introduced. Comparision of the results of fuzzy clustering with conventional clustering using a set of hypothetical data is made. An example of a practical application indicating the apparent merits of fuzzy clustering is given. This technique might show great promise when applicated to geochemical exploration problems.     

A statistical analysis applied to the Rf/φ method

A statistical analysis for the R_f/φ method is developed in the paper. The technique provides estimates of R_s, R_i and θ according to R_f and φ. Moreover, we can restore the pattern of initial orientations of marker objects by means of their frequency histogram, provided the strain is homogeneous. It is unnecessary to postulate random initial orientations if the principal directions of strain ellipsoid are known.     

Lithofacies features and mechanism of formation of “Zihe-type” time- and strata-bound iron ore deposits in central Shandong province

The Lower Palaeozoic system is a series of iron-bearing rocks consisting mainly of shallow sea-fades carbonates. On the basis of microfacies analysis of the carbonate rocks, the Lower Palaeozoic sedimentary sea basin is divided into two broad sedimentary-tectonic regions of four sedimentary facies and eight subfacies. The original iron-rich carbonates were deposited in saltlakes, lagoons, etc. of the restricted basins. Over the long geological history, the original iron formations were reconstructed to various extents by late tectonic processes. Geological observations and studies on the equilibrium mechanism of oxygen/sulfur isotopic fractionation and the composition and temperature of fluid inclusions in the minerals indicate that thermal brines played an important role in reworking of the original iron-rich carbonate rocks, which led to the formation of sedimentary-reworked strata-bound ore deposit.     

用车贝雪夫多项式预报气象产量地理分布的试验

本文以辽宁省中北部地区玉米气象产量区域分布的预报为例,论述了车贝雪夫多项式在农业气象预报中的若干应用。作者用不规则格点上的车贝雪夫多项式,以大气环流为候选预报因子,求得展开式系数依赖于4—6个因子的方程,并由此报出区域各县产量,绘出预报图,作试报检验。结果表明:车贝雪夫多项式可用于区域产量预报。最后讨论了此方法在农业气象预报其他领域(如发育期、病虫害预报)中的应用前景,指出车贝雪夫多项式用于生物学、地学预报中的意义。