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941.
由于全球经济衰退,数字标牌产业面临着一些挑战,实际情况是公司削减资本密集型项目,还是通过扩大方案的应用范围实现利润呢? 相似文献
942.
Daniel E. Canfield Jr Darren J. Pecora Kurt W. Larson Jesse Stephens Mark V. Hoyer 《Lakes & Reservoirs: Research and Management》2013,18(3):239-245
Stocking of largemouth bass is an important management tool for fish management. The stocking of hatchery‐produced fingerling or advanced‐fingerling bass to supplement bass year‐classes, however, has exhibited varying success. Utilizing a different approach, a multiyear stocking programme using wild adult largemouth bass was initiated at the Harris Chain of Lakes (3800 ha Lake Griffin; 1811 ha Lake Dora) in central Florida. Wild adult bass (24 781 fish), ranging in size from 200 mm total length (TL) to over 600 mm TL, were stocked in Lake Griffin (13 932 fish) and Lake Dora (10 849 fish). One month after stocking, the number of stocked bass caught in electrofishing catches in Lake Griffin and Lake Dora was ~10% and 22%, respectively. Estimates of mortality were similar to the native largemouth bass, although the movement of stocked fish into other connecting water bodies was extensive. For the Lake Griffin/Lake Dora stocking programme, bass were transferred at a cost of $10.09–19.89 per fish, depending on how the costs of the project are calculated ($250 000 for just the capture and transport of the fish vs. $492 775 for the total project). Considering only capture and transport costs, conservative benefit/cost ratio estimates would be $1.77/$1.00 spent for replacement and $1.85/$1.00 spent recreational costs, although the benefit/cost ratios could exceed $10/$1. Based on the present study, stocking wild adult largemouth bass is a cost‐effective tool for managing largemouth bass. 相似文献
943.
Multitasking across generations: Multitasking choices and difficulty ratings in three generations of Americans 总被引:1,自引:0,他引:1
L. Mark Carrier Nancy A. Cheever Larry D. Rosen Sandra Benitez Jennifer Chang 《Computers in human behavior》2009
This study investigated whether changes in the technological/social environment in the United States over time have resulted in concomitant changes in the multitasking skills of younger generations. One thousand, three hundred and nineteen Americans from three generations were queried to determine their at-home multitasking behaviors. An anonymous online questionnaire asked respondents to indicate which everyday and technology-based tasks they choose to combine for multitasking and to indicate how difficult it is to multitask when combining the tasks. Combining tasks occurred frequently, especially while listening to music or eating. Members of the “Net Generation” reported more multitasking than members of “Generation X,” who reported more multitasking than members of the “Baby Boomer” generation. The choices of which tasks to combine for multitasking were highly correlated across generations, as were difficulty ratings of specific multitasking combinations. The results are consistent with a greater amount of general multitasking resources in younger generations, but similar mental limitations in the types of tasks that can be multitasked. 相似文献
944.
This paper introduces the first detailed reaction mechanisms for Br/Hg chemistry in flue gas, and interprets the Hg oxidation performance across a broad range of Br injection rates in recent field tests at Plant Miller. Homogeneous chemistry with Br species is much faster than with Cl species because the Br atom concentrations at the furnace exit are three to four orders of magnitude greater. The dominant channels with Br are analogous to those for Cl, whereby a Br atom partially oxidizes Hg0 into HgBr which is then oxidized into HgBr2 by Br2. Mercury also oxidizes heterogeneously on unburned carbon (UBC) with Br species. This mechanism is also analogous to the surface mechanism for Cl species, except that (i) Hg0 adsorption is faster on brominated sites and (ii) the high Br atom concentrations promote recombination reactions which maintain very low surface coverages of Hg/Br species. Hence, Br addition does not promote the production of particulate-Hg. Catalytic Hg0 oxidation on SCR monoliths by Br species is more than 40 times faster than by Cl species and follows a similar mechanism. For all Br loadings over 10 ppmw in the field tests, essentially all Hg0 entering the SCR was oxidized. 相似文献
945.
946.
H. Moll W. Theisen W. Tillmann L. Weber 《Materialwissenschaft und Werkstofftechnik》2005,36(8):365-369
Use of a Scratch Pendulum for Quantification of the Abrasive Behaviour in Machining Stones The machining of natural stones is one of the most demanding applications of today´s cutting technique. Modern stone processing is based on grinding and it is usually done with diamond based tools. The achievable material removal rate is process dependant and mainly determined by tool speed and infeed. The tool durability depends on the adjustment of the parameters to the wear resistance of the processed material. This resistance is a material characteristic value. Using a scratch pendulum, it is possible to determine the energy needed to create a defined scratch and relate it to the induced material loss and the chipped material volume. The analysis provides a value which, after verification by industrial production data, can be seen as characteristic for the material. It therefore enables the quantification of a material dependant scratch resistance. 相似文献
947.
948.
On March 10, 2009, the US Environmental Protection Agency (EPA) proposed a new rule, Mandatory Reporting of Greenhouse Gases. When final, the rule would compel most large sources of greenhouse gases (GHGs) to report their emissions to EPA as well as fossil fuel suppliers and vehicle engine manufacturers to report their fuel sales and engine emissions rates, respectively. We suggest a number of improvements to the rule that would enhance compatibility with expected future climate legislation and enable a broader range of policies and analysis: (1) lower the threshold for reporting to a level more consistent with expected future legislation, (2) require reporting of electricity use along with direct emissions, (3) require reporting of emissions per unit output for a small number of selected sectors, (4) include a system of identifying corporate ownership of reporting facilities, and (5) identify a path toward coverage for sectors that were left out of the proposal due to underdeveloped reporting protocols. 相似文献
949.
Khwankaew Dhanasettakorn Ingolf U. Grün Mengshi Lin Mark Ellersieck 《Sensing and Instrumentation for Food Quality and Safety》2009,3(2):122-129
A new pasta product was developed by partially replacing durum wheat flour with beef heart to enhance its nutritional value.
Physiochemical changes of the pasta were investigated by vibrational spectroscopy, namely Fourier transform infrared (FT-IR)
and Raman spectroscopy. Relationships between pasta texture and the intensity of vibrational spectra were established. Lipid-protein
complex formation, β-sheet arrangement, degree of polysaccharide polymerization, and cysteine thiol group were related to hardness and chewiness
of pasta. The lipid portion and β-sheet structure were two significant parameters for explaining pasta adhesiveness, while pasta firmness might be related
to β-sheet alignment and the polysaccharide network. Pasta cohesiveness might involve the α-helical structures and hydrogen bonding formation in the gluten network. However, no variable met the p < 0.1 significance level for inclusion into the model to explain pasta springiness. These results reveal that FT-IR and Raman
spectroscopy could be employed to evaluate the physical chemistry of pasta and showed a potential use for quality assessment
in pasta products. 相似文献
950.
Brian Williams Mark Cummins José Neira Paul Newman Ian Reid Juan Tardós 《Robotics and Autonomous Systems》2009,57(12):1188-1197
Loop closure detection systems for monocular SLAM come in three broad categories: (i) map-to-map, (ii) image-to-image and (iii) image-to-map. In this paper, we have chosen an implementation of each and performed experiments allowing the three approaches to be compared. The sequences used include both indoor and outdoor environments and single and multiple loop trajectories. 相似文献