机械磨损部件的摩擦润滑自修复

磨损是导致能源浪费和机械零件失效的主要原因之一，为减少或抑制摩擦磨损，通过润滑油品配方设计和有效利用摩擦产生的物理化学作用，提出了摩擦适应，摩擦成膜自修复，原位摩擦化学自修复，微流变及场效应渗镀整平技术五种自修复机理。     

E-Beam irradiation of bagged, ready-to-eat spinach leaves (Spinacea oleracea): an engineering approach

ABSTRACT:  We experimentally assessed the efficacy of electron beam irradiation to ensure the safety and quality of ready-to-eat spinach leaves using a 2-MeV Van de Graff accelerator. Spinach leaves (approximately 8 g) inside petri dishes were irradiated up to 1 kGy and stored at 4 °C for 15 d. Nonirradiated samples served as controls. Color, texture, vitamin C, total carotenoids, and chlorophyll content were measured using standard methods. Sensory analysis was performed by 15 untrained panelists using a 9-point hedonic scale. Color of control and irradiated samples showed slight variation throughout storage. Firmness of all samples changed significantly ( P < 0.05) by half the storage time; however, exposure to radiation did not cause significant differences by the end of shelf life. Irradiation did not affect the chlorophyll and total carotenoid content, though it produced samples with significantly lower ( P < 0.05) vitamin C content. For all treatments, chlorophyll content decreased by day 15 while total carotenoids remained constant. Although, by the end of refrigerated storage, all the irradiated samples received slightly lower odor scores, sensory analysis revealed that irradiation had little or no effect on the overall quality of spinach leaves. We also simulated the dose distribution within a bag of spinach leaves irradiated using a 10-MeV linear accelerator (0.3 to 1 kGy) to quantify the problem of nonuniform dose absorbed at different parts of the bag and predict death of a pathogen such as Escherichia coli O157:H7. The simulation results confirmed that it is feasible to irradiate baby spinach leaves (up to 1 kGy) to eliminate E. coli 0157:H7 while maintaining the overall quality of the produce.     

Secondary production and biomass of Cladocera in marginal lakes after the recovery of their hydrologic connectivity in a river–reservoir transition zone

Secondary production and biomass of Cladoceran populations were studied in two marginal lakes whose connections to a tropical river were re‐established after a prolonged drought period. This study investigates the process of the recovery of the cladoceran populations after the hydrologic reconnection with the river was established. It also compares the energetic dynamic of Cladoceran populations in two lakes, one with a wide and another with a narrow connection to the river. Samples were collected every 48 h for 1 month, immediately after the river water inflow to the lakes, and 7 months after the reconnection with the river during a period of hydrologic stability of the lakes. Secondary production and biomass were compared between lakes and periods, to identify the main controlling factors for the observed variations in Cladoceran productivity. Cladocerans were more productive during the rainy period, immediately after the increased water volume, when high water temperatures were recorded in the two lacustrine systems. Secondary production and biomass values were higher in the more eutrophic lake, wherein the water chemical and physical characteristics presented slow alterations during the rainy period. Although the lake with large spatial heterogeneity and linkages with the river exhibited high Cladoceran richness, the secondary production and biomass were low. Variations in water volumes and temperatures and changes in trophic status affected the secondary production and biomass of the main Cladoceran species in the two studied lakes.     

900MW超临界直流锅炉制造工艺特点

90 0MW超临界直流锅炉与上海锅炉厂有限公司以往制造的锅炉产品相比 ,其省煤器、过热器、再热器及相应集箱的材料、结构和制造工艺除了尺寸较大之外无大的差异。此锅炉制造中最大的难点在于螺旋水冷壁 ,特别是其中过渡段的制造。介绍 90 0MW超临界直流锅炉制造工艺的一些特点 ,特别是螺旋水冷壁过渡段制造中的难点及应采取的措施     

转捩模型在叶栅粘性流数值模拟中的应用方法研究

通过求解N—S方程对流场进行数值模拟，已成为研究透平机械的一个重要手段。而建立合适的转捩模型能够使流场数值模拟更为准确。本文作者利用现有的试验数据对Abu—Ghannam and Shaw^[1]转捩模型(AGS转捩模型)进行了修正，提出了利用弧长雷诺数模型确定转捩区长度的思想，并对计算结果与试验值进行了比较。     

土石坝工程领域的若干创新与发展

我国高土石坝数量居世界之首,保证高坝大库建设与长期运行安全是国家经济和公共安全保障的重大需求。系统总结了长江科学院近年来在土石坝工程领域的若干创新与发展。提出了基于“旁压模量当量密度法”的粗粒料级配相似理论试验方法;介绍了研发的系列CT三轴仪,实现了粗粒料组构要素的定量测量;提出了三轴试验中加载板与试样之间由滑动摩擦变为滚动摩擦、整体式接触变为分散式接触的减摩新方法,研发了相关减摩装置;研制了大尺寸、高压力、微摩擦、刚柔复合加载的土工真三轴仪;揭示了粗粒料真实三维应力条件下的强度与变形变化规律、湿化与蠕变变形特性;构建了粗粒料三参量非线性K-K-G剪胀模型、六参数湿化模型、九参数蠕变数学模型及相应的参数确定方法;基于当量密度法的原创思想,提出了利用旁压试验间接确定超百米级深厚覆盖层现场密度的试验方法。上述研究成果可为高土石坝工程建设提供重要科技支撑。     

我国旱涝交替事件识别及演变规律

为了识别我国旱涝交替事件以及探究其时空演变规律,引入降雨距平指数(RAI),并提出了一种在月尺度上识别旱涝交替事件的简便易操作的研究方法.结果表明:我国旱涝交替事件具有明显的年内分布规律,4—8月份旱涝交替事件发生频次明显增加,8月份以后,旱涝交替事件发生次数减少.不同月份,旱涝交替事件高频区的分布也不同,4—6月份主...     

Thermo-mechanical,structural characterization and antibacterial performance of solvent casted polylactide/cinnamon oil composite films

Polylactic acid (PLA) based composite films were prepared by incorporating polyethylene glycol (PEG) and cinnamon oil (CIN) (25 and 50% w/w of PLA) via solution casting method. Morphological, structural, thermo-mechanical, spectral, and antibacterial properties of PLA/PEG/CIN films were investigated. Tensile strength (TS) and tensile modulus (TM) of the film decreased, while the elongation at break (EAB) increased by increasing CIN concentration. Using the principle of time-temperature superposition, the viscous modulus and the complex viscosity of composite films at selected temperatures and frequencies (time scales) were superimposed well in an extended frequency range. Thermal properties decreased substantially with incorporation of CIN. Significant changes in molecular organisation and intermolecular interactions between CIN and PLA/PEG matrix were observed through the FTIR spectroscopy. Scanning electron microscopic (SEM) revealed rough surfaces of the composite films. The effectiveness of composite films was tested against Listeria monocytogenes and Salmonella typhimurium inoculated in chicken samples, and it was found that the film containing 50% CIN showed an antibacterial activity during 16 days storage at refrigerated condition. The developed film has a potential for packaging of chicken samples with extended storage.     

基于相变的井网水驱控制程度分析——以萨尔图中区西部二、三类油层为例

根据萨尔图中区西部的高密度测井资料,利用沉积单元单砂体精细解剖结果,开展了基于井网的砂体相变程度和控制程度分析,得出了注采井距对不同类型河道砂体相变率和控制率的影响规律。在此基础上,为充分考虑砂体平面非均质性的影响,进行了基于相变的水驱控制程度分析与评价。研究结果表明:利用传统方法统计得出的水驱控制程度值往往偏高;随着井网的加密,不同类型河道砂体的水驱控制程度变化幅度有所不同;进行沉积单元细分后,基于相变的水驱控制程度值降低,并更接近油藏实际。     

A Puzzle of Quantum Phase Transition on Gd-IMC by Tuning of Conduction Electron Concentration

Based on the critical unstable of both crystal and magnetic structure of Gd-intermetallic compound near the competition of two strongly independent subsystem （＂local 4f7＂ and ＂conduction electron concentration＂）, a new QPT （quantum point transition） is predicted by calculation of： （1） The band structure and density of state by density functional theory where a strong narrowing fluidity of fermions around EF with shifted to negative value ＂-0.8 eV ＂is observable in the Gd-intermetalliccompound system while in the Y-case, it is not dominated. An antiferromagnetic state on the fluidity of conduction band can be investigated; （2） The internal magnetic field due to short range exchange interaction Jij between the nearest neighbor of local magnetic moment of stable s-state of Gd （L = 0） through the mean field approximation and of Eigenvalue-Eigenfunction ~.（k） are calculated. While a strong negative value of Jy is predicted, the eigenvalue L（k） of the system shows a strong antiferromagnetic phase in the reciprocal lattice direction 〈010〉, 〈001〉 in the correlation length 3.38 ~A. Although the antiferromagnetic state at Rc 〈_ 3.38 °A is a puzzle but it is completely dominated at Rc = 9 °A after passing through the competition between ）.λmin（O） and λmin（π） in the ranger of 3.2 °A 〈 Rc 〈 9 °A. Since both of the antiferromagnetic subsystems are sensitive to the predicted KF, the effect of decreasing of conduction electron is proposed to investigate, the change of the antiferromagnetic ordering state to the competition of ferromagnetic state （in direction 〈010〉） and antiferromagnetic state （in direction 〈001 〉 and 〈 100〉） resulted to paramagnetic state in the long range Rc = 9 °A.