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91.
Martin Oschatz Marcus Rose Nicole Klein Thomas Freudenberg Gleb Yushin 《Carbon》2010,48(14):3987-3992
A hierarchical and highly porous carbide-derived carbon (CDC) was obtained by nanocasting of pre-ceramic precursors into cubic ordered silica (KIT-6) and subsequent chlorination. Resulting CDC replica materials show high methane and n-butane uptake and excellent performance as electrode materials in supercapacitors. 相似文献
92.
Aimee Lee S. Houde Chris C. Wilson Bryan D. Neff 《Journal of Great Lakes research》2017,43(1):211-215
Economically and culturally important salmonid species often compete with Atlantic salmon (Salmo salar) released from stocking programs or that escaped during aquaculture production. Such competitive interactions may lower the individual fitness of these species by reducing survival and body growth. Here, we exposed juvenile brown trout (S. trutta), rainbow trout (Oncorhynchus mykiss), Chinook salmon (O. tshawytscha), and coho salmon (O. kisutch) to juvenile Atlantic salmon in artificial streams for 10 months. Survival and fitness-related traits of the four species were not negatively impacted by the presence of Atlantic salmon. The results suggest that brown trout and rainbow trout have better competitive abilities than Atlantic salmon, and that Chinook salmon and coho salmon have limited competitive interactions with Atlantic salmon. Although we discuss certain environmental conditions that can favor Atlantic salmon as a competitor at the juvenile life stage, Atlantic salmon may have little impact on the productivity of these four species. 相似文献
93.
A 1 wt% lysozyme solution was used as a model fluid to test a previously formulated mathematical model for the initial chemical reaction fouling rate of a heat transfer surface. The experimental results showed that, at a given wall temperature, a maximum initial fouling rate existed over a range of fluid velocities. The maximum rate and the fluid velocity at which it occurred both increased as the wall temperature increased. These observations were consistent with the model. Quantitatively, the average absolute percent deviation between the experimental results and the optimum model predictions was 23,3%. The decrease in initial fouling rate with increasing velocity at high fluid velocities was even greater than predicted by the model. 相似文献
94.
The understanding of violent criminal behavior is hindered by definitional problems in both the legal and research communities. Different definitions of violent criminal behavior and different classifications of the severity of violence are fundamental problems that need to be resolved in order to develop better conceptual models of the precursors to criminal violence that can inform management and treatment of violent young offenders. This study evaluated 6 classifications of violent juvenile offenses derived from the legal system and published research. The authors compare frequencies from different classifications and examine the influence of classifications on observed associations with expected predictor variables. Differences in frequencies and perceived associations between classifications highlight the need to adopt a consistent method of coding violent offenses for research purposes in order to obtain valid results that are capable of informing policy, the judiciary, and the development of effective interventions. The final classification system offers a method of systematic coding based on the type, frequency, and outcome of the violent behavior that distinguishes between levels of violence severity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
95.
本研究的主要目标是在鼓励创造性思维的同时,建立一个结构化方法用于阐明产品生命周期策略。当前提倡采用适用于大多数产品的通用规则。联系“通用性”原则,与“放之四海皆准”的方法相比,本研究找出了影响产品生命终期的主要因素。研究结果可分为两个核心部分。第一,根据产品的技术特性,该方法论确定了合理的产品生命终期策略第二,为了评估和验证该方法,将产品生命终期策略的分类和当前工业实践进行了对比,开发的产品生命终期设计顾问(ELDA)软件,指导生产商确定适合的产品生命终期策略。对产品生命终期进行分类的能力使得设计者能够重新设计对环境负荷较小产品。这篇文章为设计者和生产管理者提供了合适的产品生命终期策略。通过更深入的理解相应产品的生命终期策略,本文的研究结果能够帮助设计者开发适合他们情况的、系统的产品生命终期策略。通过技术革新或者价值链的改进,将ELDA的结果运用于生命终期改善。 相似文献
96.
Nayak J. Tuncel E. Rose K. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2006,52(10):4626-4629
This correspondence presents a novel application of the theta function defined by Lovasz. The problem of coding for transmission of a source through a channel without error when the receiver has side information about the source is analyzed. Using properties of the Lovasz theta function, it is shown that separate source and channel coding is asymptotically suboptimal in general. By contrast, in the case of vanishingly small probability of error, separate source and channel coding is known to be asymptotically optimal. For the zero-error case, it is further shown that the joint coding gain can in fact be unbounded. Since separate coding simplifies code design and use, conditions on sources and channels for the optimality of separate coding are also derived 相似文献
97.
Effects of foam on ocean surface microwave emission inferred from radiometric observations of reproducible breaking waves 总被引:1,自引:0,他引:1
Padmanabhan S. Reising S.C. Asher W.E. Rose L.A. Gaiser P.W. 《Geoscience and Remote Sensing, IEEE Transactions on》2006,44(3):569-583
WindSat, the first satellite polarimetric microwave radiometer, and the NPOESS Conical Microwave Imager/Sounder both have as a key objective the retrieval of the ocean surface wind vector from radiometric brightness temperatures. Available observations and models to date show that the wind direction signal is only 1-3 K peak-to-peak at 19 and 37 GHz, much smaller than the wind speed signal. In order to obtain sufficient accuracy for reliable wind direction retrieval, uncertainties in geophysical modeling of the sea surface emission on the order of 0.2 K need to be removed. The surface roughness spectrum has been addressed by many studies, but the azimuthal signature of the microwave emission from breaking waves and foam has not been adequately addressed. Recently, a number of experiments have been conducted to quantify the increase in sea surface microwave emission due to foam. Measurements from the Floating Instrumentation Platform indicated that the increase in ocean surface emission due to breaking waves may depend on the incidence and azimuth angles of observation. The need to quantify this dependence motivated systematic measurement of the microwave emission from reproducible breaking waves as a function of incidence and azimuth angles. A number of empirical parameterizations of whitecap coverage with wind speed were used to estimate the increase in brightness temperatures measured by a satellite microwave radiometer due to wave breaking in the field of view. These results provide the first empirically based parameterization with wind speed of the effect of breaking waves and foam on satellite brightness temperatures at 10.8, 19, and 37 GHz. 相似文献
98.
Two main security threats exist for DNS in the context of query/response transactions. Attackers can spoof authoritative name servers responding to DNS queries and alter DNS responses in transit through man-in-the-middle attacks, and alter the DNS responses stored in caching name servers. The IETF has defined the digital signature-based DNSSEC for protecting DNS query/response transactions through a series of requests for comments. 相似文献
99.
Managerial Competences for ERP Journeys 总被引:2,自引:0,他引:2
This paper investigates the managerial competences required for the complex interactions required to successfully integrate an Enterprise Resource Planning system into an organization—the ERP journey. A feature of the study (a five year longitudinal study of a Danish production company implementing SAP R/3) was the rise and fall of the ERP project managers. The study showed that different stages of the ERP journey required different competences from the managers. A manager with a certain competence mix might successfully oversee part of the ERP journey, but a different blend of competences was required to manage other parts. The paper concludes that a wide range of competences are required: personal, business and technical. The competence mix should be expected to vary through the journey, and is often too much to expect of one person. 相似文献
100.
Guided wave nuances for ultrasonic nondestructive evaluation 总被引:3,自引:0,他引:3
Recent developments in guided wave generation, reception, and mode control show that increased penetration power and sensitivity are possible. A tone burst function generator and appropriate signal processing are generally used. Variable angle beam and comb-type transducers are the key to this effort. Problems in tubing, piping, hidden corrosion detection in aging aircraft, adhesive and diffusion bonding, and ice detection are discussed. Additionally, sample configurations, inspection objectives, and logic are being developed for such sample problems as defect detection and analysis in lap splice joints, tear straps, cracks in a second layer, hidden corrosion in multiple layers, cracks from rivet holes, transverse cracking in a beam, and cracks in landing gear assembly. Theoretical and experimental aspects of guided wave analysis include phase velocity, group velocity, and attenuation dispersion curves; boundary element model analysis for reflection and transmission factor analysis; use of wave structure for defect detection sensitivity; source influence on the phase velocity spectrum, and the use of angle beam and comb transducer technology. Probe design and modeling considerations are being explored. Utilization of in-plane and out-of-plane displacement patterns on the surface and longitudinal power distribution across the structural cross-section are considered for improved sensitivity, penetration power, and resolution in nondestructive evaluation. Methods of controlling the phase velocity spectrum for mode and frequency selection are available. Such features as group velocity change, mode cut-off measurements, mode conversion, amplitude ratios of transmission, and reflection factors of specific mode and frequency as input will be introduced for their ability to be used in flaw and material characterization analysis. 相似文献