棉花产量要素预测模型

引起棉花产量波动的主要产量构成要素是株铃数和单铃重,作者将大田监测与气候统计相结合道德预测单株现蕾数,成铃雍铃重,对对最终产量进行预后,提高了产量预后准确率。     

膨胀岩土体湿度本构模型的探讨

水在膨胀性岩土中发挥着至关重要的作用,而膨胀岩土体中的水分分布随空间和时间而改变。文中引入折减吸力,通过分析提出膨胀屈服面的概念,并给出相应函数表达形式及硬化规律。从非饱和渗流出发,推导体积可变时的中力分布控制方程,并建立膨胀岩土体湿度应力场理论的耦合方程。     

Physically based modelling of shallow landslide sediment yield at a catchment scale

 A shallow landslide erosion and sediment yield component, applicable at the basin scale, has been incorporated into the physically based, spatially distributed, hydrological and sediment transport modelling system, SHETRAN. The component determines when and where landslides occur in a basin in response to time-varying rainfall and snowmelt, the volume of material eroded and released for onward transport, and the impact on basin sediment yield. Derived relationships are used to link the SHETRAN grid resolution (up to 1 km), at which the basin hydrology and final sediment yield is modelled, to a subgrid resolution (typically around 10–100 m) at which landslide occurrence and erosion is modelled. The subgrid discretization, landslide susceptibility and potential landslide impact are determined in advance using a geographic information system (GIS), with SHETRAN then providing information on temporal variation in the factors controlling landsliding. The ability to simulate landslide sediment yield is demonstrated by a hypothetical application based on a catchment in Scotland. Received: 30 October 1996 · Accepted: 25 June 1997     

The definition of yield for bonded materials

Summary In this paper the different definitions of yield for bonded materials are reviewed. It is suggested that yield should be defined based on changes in stiffness from the tangential stiffness versus axial strain graph. Comparisons are made with a recent framework proposed by Jardine and good agreement is shown between Jardine's approach and that presented here, in respect of an initial yield and a final yield point. However, based on data from natural and artificially bonded soils, an additional yield point, that of second yield, is identified where a major drop in stiffness is initiated. In the past the identification of final yield has been used to identify the border between two modes of failure for the shear behaviour of a bonded soil. The first mode is defined when shearing at low confining stresses and the bonded material's strength is greater than that of the destructured soil. A second mode is defined when shearing at high confining stresses where its strength is unaffected by the bonds. In this paper, based on the identification of the second yield, a new transitional mode of failure is clarified at intermediate stresses, where although the soil yields at the initial stages of shearing, it still demonstrates strengths higher than those of the destructured soil due to the post-yield influence of the bonds.     

Nutrient Enrichments of Waters of "Golfo de San Jose" (Argentina, 42 oS), Growth and Species Selection of Phytoplankton

Abstract. Coastal Patagonian sea waters had been differentially nutrient-enriched to determine (i) the magnitude of the algal biomass supported and (ii) which species were able to best compete for the available nutrients. Nitrogen was found to be the nutrient limiting growth of the natural phytoplankton population. The addition of NO₃ at 25 μg at 1^-1 led to a 10 to 30 μg 1^-1 increase in chlorophyll a in all but those treatments containing trace metal additions. The best yield coefficients were obtained when a chelator (EDTA) was added with NO₃. A pool of nine diatom species were common in the N0₃ supplemented waters and the addition of vitamins along with NO₃ allowed two of the nine species to dominate.     

海湾扇贝大水体高产育苗技术的研究

本文主要用延长亲贝低温培育时间和强化营养，抛劣选优质亲贝等措施，保证亲贝积温达４００℃以上产卵．在此技术上严格控制亲贝产卵时间和精子浓度，逐步提高幼虫培育水温，加大换水和投饵，勤倒池等措施，于２９９ｍ３水体中，培育出２．６５亿粒商品苗（０．５ｃｍ大小），取得可喜的经济效益。     

A Discusion on Limited Load-Carrying Capacity of Rectangular Plates

The elastic-plastic method is often used in designing the inner flat bulkhead plates of submarines, and the upper structure of ships and drilling platforms. Such bulkhead plates can bear the load only once. For the improvement of the load-carrying capacity or the reduction of the weight of plates, the yield line analytical method is employed in this paper to design the bulkhead plate to improve economy and increase the effiective load. Besides, a further sutdy of this method has been made theoretically and experimentally, and the data of the limited load-carrying capacity of the plate have been obtained. Furthermore, the safety coefficients for such a method are presented, which can be used as reference for related departments and staffs.