信息系统工程监理中的进度控制

该文从信息系统工程监理的概念与必要性出发,重点论述了监理的一个关键性领域———进度监理,即如何从监理的角度对进度实行控制,包括评价进度计划的合理性、进度进程与变化的跟踪、协助并监督进度的调整等,从而保证功能按计划优质完成。     

直接探测测风激光雷达的性能分析

综述了激光雷达大气风场测量的方法，提出了采用直接探测到量三维风场分布的F-P干涉仪方法，简述了测量原理，分析了系统的性能和测量误差，比较了基于分子散射和气溶胶散射的系统测量精度，给出了基于瑞利散射的激光雷达系统方案。     

Relating the Morphology of Poly(p‐phenylene vinylene)/Methanofullerene Blends to Solar‐Cell Performance

The performance of bulk‐heterojunction solar cells based on a phase‐separated mixture of donor and acceptor materials is known to be critically dependent on the morphology of the active layer. Here we use a combination of techniques to resolve the morphology of spin cast films of poly(p‐phenylene vinylene)/methanofullerene blends in three dimensions on a nanometer scale and relate the results to the performance of the corresponding solar cells. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and depth profiling using dynamic time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) clearly show that for the two materials used in this study, 1‐(3‐methoxycarbonyl)propyl‐1‐phenyl‐[6,6]‐methanofullerene (PCBM) and poly[2‐methoxy‐5‐(3′,7′‐dimethyloctyloxy)‐1,4‐phenylene vinylene] (MDMO‐PPV), phase separation is not observed up to 50 wt.‐% PCBM. Nanoscale phase separation throughout the film sets in for concentrations of more than 67 wt.‐% PCBM, to give domains of rather pure PCBM in a homogenous matrix of 50:50 wt.‐% MDMO‐PPV/PCBM. Electrical characterization, under illumination and in the dark, of the corresponding photovoltaic devices revealed a strong increase of power conversion efficiency when the phase‐separated network develops, with a sharp increase of the photocurrent and fill factor between 50 and 67 wt.‐% PCBM. As the phase separation sets in, enhanced electron transport and a reduction of bimolecular charge recombination provide the conditions for improved performance. The results are interpreted in terms of a model that proposes a hierarchical build up of two cooperative interpenetrating networks at different length scales.     

Electronic gate detection for cell or particle counting and sizing in liquids: front-end characteristics, flow-dependent gate impedance, and its remediation

The detection sensitivity and the sizing resolution of electronic gating are inherently limited by fluctuating gate impedance and flow-induced noise. Instabilities of this type, as shown, are due to varying flow patterns of the carrier liquid beyond the gate. Their effects, although largely hidden in dc-operated gating, cause broadening and shift of cell/particle-size distributions under measurement. RF-operated gating, more specifically the demodulation operation, is much more hindered. For an investigation of these effects, a physical model is proposed along with a procedure for the identification of the system parameters. A detector of dedicated concept is used for evaluating the model, and, more specifically, for investigating the impact of configurational and hydrodynamic parameters. Experiments prove that the origin of flow-dependent gate impedance is to be located inside a zone of only a few-micrometer extent at the gate outlet. This is confirmed by the calculated electric field patterns. On such grounds, electrode configurations are proposed that minimize the current density in the zone of hydrodynamic instability and, hence, the flow-induced noise. The same configurations also minimize the impedance of the gate as signal source, facilitating broadband operation, and multifrequency cell impedance measurements.     

Simulation of runoff and phosphorus transport in a Carpathian catchment,Slovakia

A comprehensive, GIS‐based modelling approach is developed to estimate runoff and phosphorus transport within a watershed at a daily time step. The approach relies on the use of GIS data for deriving major critical model parameters that exhibit distinct spatial variability over the catchment. Surface runoff is calculated by a modified rational method, which depends upon rainfall intensity, soil moisture status, slope, land‐use and soil characteristics. Phosphorus loading is estimated as a function of the runoff volume and the event mean concentration for different land use categories. A diffusive approximation method is used to trace runoff and phosphorus transport to the basin outlet. The modelling approach is tested in the Margecany catchment, Hornad River basin, Slovakia, to simulate runoff, phosphorus loading, and its transport on a daily time scale using data observed between 1995 and 2000. Satisfactory results of the hydrographs and phosphorus concentration at the basin outlet are obtained, though more efforts regarding the phosphorus cycling and its biochemical reactions need to be clarified by further research. Copyright © 2006 John Wiley & Sons, Ltd.     

A Micellar Route to Ordered Arrays of Magnetic Nanoparticles: From Size‐Selected Pure Cobalt Dots to Cobalt–Cobalt Oxide Core–Shell Systems

Starting with Co‐salt‐loaded inverse micelles, which form if the diblock copolymer polystyrene‐block‐poly(2‐vinylpyridine) is dissolved in a selective solvent like toluene and CoCl₂ is added to the solution, monomicellar arrays of such micelles exhibiting a significant hexagonal order can be prepared on top of various substrates with tailored intermicellar distances and structure heights. In order to remove the polymer matrix and to finally obtain arrays of pure Co nanoparticles, the micelles are first exposed to an oxygen plasma, followed by a treatment in a hydrogen plasma. Applying in‐situ X‐ray photoelectron spectroscopy, it is demonstrated that: 1) The oxygen plasma completely removes the polymer, though conserving the original order of the micellar array. Furthermore, the resulting nanoparticles are entirely oxidized with a chemical shift of the Co 2p_3/2 line pointing to the formation of Co₃O₄. 2) By the subsequent hydrogen plasma treatment the nanoparticles are fully reduced to metallic Co. 3) By exposing the pure Co nanoparticles for 100 s to various oxygen partial pressures pequation/tex2gif-inf-5.gif, a stepwise oxidation is observed with a still metallic Co core surrounded by an oxide shell. The data allow the extraction of the thickness of the oxide shell as a function of the total exposure to oxygen (pequation/tex2gif-inf-7.gif × time), thus giving the opportunity to control the ferromagnetic–antiferromagnetic composition of an exchange‐biased magnetic system.     

轿车副车架模态试验与分析

本文将现代测试手段和模态分析技术相结合，介绍了某轿车副车架的试验模态分析方法，采用白噪声随机激励法进行了模态试验，并应用模态分析软件辨识其模态参数，为进一步的理论分析及改进结构设计提供了指导。     

油气输导体系的类型及配置关系

将输导体系划分为储集层输导体系、断裂输导体系和不整合输导体系3大类，8种类型，指出输导体系的时空配置关系是决定油气藏的重要因素；着重阐明了输导层在空间和时间上的配置关系，认为这些配置关系是影响输导体系有效性的重要因素；提出了运移级次性的概念，讨论了划分运移级次对油气运移研究的意义，指出准噶尔盆地西北缘邻近玛湖以储集层输导体系和不整合输导体系为主．边缘地区以断层输导体系为主。浅层油气成藏期主要取决于断层的活动期。     

Biofiltration of toluene in the absence and the presence of ethyl acetate under continuous and intermittent loading

BACKGROUND: Two peat biofilters were used for the removal of toluene from air for one year. One biofilter was fed with pure toluene and the other received 1:1 (by weight) ethyl acetate:toluene mixture. RESULTS: The biofilters were operated under continuous loading: the toluene inlet load (IL) at which 80% removal occurred was 116 g m^?3 h^?1 at 57 s gas residence time. Maximum elimination capacity of 360 g m^?3 h^?1 was obtained at an IL of 745 g m^?3 h^?1. The elimination of toluene was inhibited by the presence of ethyl acetate. Intermittent loading, with pollutants supplied for 16 h/day, 5 days/week, did not significantly affect the removal efficiency (RE). Biomass was fully activated in 2 h after night closures, but 6 h were required to recover RE after weekend closures. Live cell density remained relatively constant over the operational period, while the dead cell fraction increased. Finally, a 15 day starvation period was applied and operation then re‐started. Performance was restored with similar re‐acclimatization period to that after weekend closures, and a reduction in dead cell fraction was observed. CONCLUSION: This study demonstrates the capacity of the system to handle intermittent loading conditions that are common in industrial practices, including long‐term starvation. Copyright © 2008 Society of Chemical Industry