种植密度和施肥对马铃薯养分吸收及土壤肥力的影响

在普施２２５ｔ·ｈｍ－２农家肥和固定Ｎ：Ｐ２Ｏ５：Ｋ２Ｏ比例２：１：３的条件下，研究了不同种植密度和施肥量对马铃薯品种“川芋早”矿质养分吸收利用和土壤肥力的影响。结果表明：加大种植密度和提高施肥水平均使植株群体的每生产千公斤薯块的Ｎ，Ｐ２Ｏ５，Ｋ２Ｏ的吸收量增加，提高肥料的利用率，尤其是高密高肥和高密中肥处理显著。农家肥的施用可以增加土壤中有机质和速效养分的含量，特别是与无机化肥配合施用效果更好     

高合金不锈钢在降膜板式蒸发器上的应用

外流降膜板式蒸发器作为替代列管式蒸发器的新设备应用于氧化铝行业,其板片材质处于一个摸索选择的过程。本文就高合金不锈钢板片的失败事例进行分析,通过试验、试用,最终找到较为理想的材质。     

水与可持续发展

论述了水在可持续发展中的地位。当今存在的4大水问题，评估了未来的水形势，提出了解决水问题的途径。     

土壤固化剂在水利工程中的应用试验

为了准确掌握固化剂在水利工程中的应用范围，特别是能否在北方季节性冻土地区应用于渠道衬砌，针对应用固化剂固结土进行研究试验．根据固化剂特点，选择宁夏唐徕渠、汉延渠的渠床土及征沙渠风积沙、镇北堡粗沙，进行强度试验．实践证明：在固化剂含量一定(20．42％)的情况下，影响固结强度的主要因素是含水率．最优固结含水率为16．5％．得出结论：土壤固化剂作为一种新型建筑材料，应用于强度要求较低的工程建设中，技术是可行的，其固化沙石的效果较黏土、沙性土的效果显．     

Construction Effect on Load Transfer along Bored Piles

The load transfer behavior along bored piles is affected by details of pile construction particularly those imposing stress and moisture changes to the surrounding soils. An investigation involving moisture migration tests, in situ horizontal stress measurements, and borehole shear and pressuremeter tests shows clear effects of construction that lead to subsequent changes in soil properties. The construction of bored piles in Singapore and the region often involves casting of concrete either in unsupported “dry” boreholes or in “wet” boreholes filled with water. It is necessary to differentiate these two extreme construction conditions in bored pile design. Based on triaxial compression and pressuremeter tests on the residual soil of the Jurong Formation in Singapore, the variation of soil modulus with shear strain can be described by a hyperbolic function. A procedure is recommended for assessing the combined effect of stress relief and soaking on soil modulus by introducing a modulus reduction factor. Modulus degradation curves from pressuremeter tests with the borehole conditions properly simulated are found capable of producing load transfer curves that are comparable to those deduced in the field.     

Education-Stratified Base-Rate Information on Discrepancy Scores Within and Between the Wechsler Adult Intelligence Scale-Third Edition and the Wechsler Memory Scale-Third Edition.

The Wechsler Adult Intelligence Scale--Third Edition (WAIS-III; D. Wechsler, 1997a) and the Wechsler Memory Scale--Third Edition (WMS-III; D. Wechsler, 1997b) are 2 of the most frequently used measures in psychology and neuropsychology. To facilitate the diagnostic use of these measures in the clinical decision-making process, this article provides information on education-stratified, directional prevalence rates (i.e., base rates) of discrepancy scores between the major index scores for the WAIS-III, the WMS-III, and between the WAIS-III and WMS-III. To illustrate how such base-rate data can be clinically used, this article reviews the relative risk (i.e., odds ratio) of empirically defined "rare" cognitive deficits in 2 of the clinical samples presented in the WAIS-III--WMS-III Technical Manual (The Psychological Corporation, 1997). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estimation of Length Limits for Integral Bridges Built on Clay

In this paper, the maximum length limits for integral bridges built on clay are determined as a function of the ability of steel H-piles supporting the abutments to sustain thermal-induced cyclic displacements and the flexural capacity of the abutment. First, H-pile sections that can accommodate large plastic deformations are determined considering their local buckling instability. Then, a low-cycle fatigue damage model is used to determine the maximum cyclic deformations that such piles can sustain. Next, nonlinear static pushover analyses of two typical integral bridges are conducted to study the effect of various geometric, structural, and geotechnical parameters on the performance of integral bridges subjected to uniform temperature variations. Using the pushover analyses results, design guidelines are developed to enhance and determine the maximum length limits for integral bridges built on clay. It is recommended that the maximum length of concrete integral bridges be limited to 210 m (689 ft) in cold climates and 260 m (853 ft) in moderate climates and that of steel integral bridges be limited to 120 m (394 ft) in cold climates and 180 m (590 ft) in moderate climates.     

Axial offset control of PWR nuclear reactor core using intelligent techniques

Improved load following capability is one of the main technical performances of advanced PWR (APWR). Controlling the nuclear reactor core during load following operation encounters some difficulties. These difficulties mainly arise from nuclear reactor core limitations in local power peaking, while the core is subject to large and sharp variation of local power density during transients. Axial offset (AO) is the parameter usually used to represent of core power peaking, in form of a practical parameter. This paper, proposes a new intelligent approach to AO control of PWR nuclear reactors core during load following operation. This method uses a neural network model of the core to predict the dynamic behavior of the core and a fuzzy critic based on the operator knowledge and experience for the purpose of decision-making during load following operations. Simulation results show that this method can use optimum control rod groups maneuver with variable overlapping and may improve the reactor load following capability.     

二维洪水演进数值模拟研究

本文在内蒙古包头市北梁区荒漠化土壤的质地和养分元素含量分析的基础上,与包头市大量堆积的、严重威胁环境的三种固体废弃物(粉煤灰、水库淤积物和污水沉淀物)进行了对比研究。结果表明:该三种废弃物具有细粒、富含植物生长所必需之养分元素的特点。以该区荒漠化土壤作基本土壤,三种废弃物作土壤添加剂进行了玉米、沙棘树和草坪草的种植实验,结果显示:(1)三种废弃物添加到荒漠化土壤中,能够显著增加土壤的养分含量。(2)荒漠化土壤被改造成为近轻壤土的砂壤土或轻壤土。(3)改良后的土壤能够显著增加土壤的生物生产量。     

环境因素对蔬菜累积硝酸盐影响的研究进展

蔬菜中的硝酸盐是一种对人体有害的化学物质,其含量比其它植物都高,人体摄入它会引起多种疾病。对近年来国内外有关光照、温度、气体、土壤中的水分和养分等对蔬菜硝酸盐积累的影响进行了综述。