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71.
72.
Summary This paper deals with the generation of stationaryp
th
order linear autoregressive series (calledM
p
-series) on an electronic computer. The interrelations between the coefficients of autocorrelation are discussed and a device and a flow diagram are given for the generation ofM
p
-series which possess the autocorrelation coefficients 1, 2,...
p
. The conclusion is that there is anM
p
-series for a given set of values only if there is anM
q
-series for any subset 1,...
q
withq=1,2,...q–1 and that, conversely, if there is anM
p
-series for given 1,2,...
p
, there is also anM
q
-series with 1,...
q
for 1q<p.The series withp=1, 2, 3 are treated fully and numerical examples forp=1 andp=2 are given in Fig. 4.
With 4 Figures 相似文献
Zusammenfassung In diesem Aufsatz wird besprochen wie mit Hilfe einer elektronischen Rechenmaschine stationäre lineare autoregressive Reihen der Ordnungp (M p -Reihen genannt) konstruiert werden können. Nachdem die Beziehungen zwischen den Autokorrelationskoeffizienten abgeleitet worden sind, wird ein Schema und ein Flußdiagramm zur Erzeugung vonM p -Reihen gegeben, die vorgegebene Autokorrelationskoeffizienten 1,... p besitzen. Das Ergebnis lautet: EineM p -Reihe für eine Gruppe von gegebenen Werten 1,... p ist nur möglich, wenn eineM q -Reihe für jede Untergruppe 1,... q mitq=1, 2, ...p–1 möglich ist. Wenn einmal eineM p -Reihe mit gegebenen 1,... p existiert, dann existiert ebenfalls jedeM q -Reihe mit 1,... q , wobei 1q<p ist.Die Fällep=1, 2, 3 werden ausführlich behandelt, während die Abb. 4 numerische Beispiele fürp=1 undp=2 zeigt.
With 4 Figures 相似文献
73.
Vacant land is a significant issue in virtually every country across the globe. This study presents a current inventory of vacant land and structural abandonment in the urban United States. Using survey data, it analyses vacant land trends by region and city type. Nationally, an average 16.7% of large US cities’ land area is considered vacant, with approximately 4% of city addresses unoccupied. The ratio of vacant land to city size has increased by 1.3 percentage points since 1998 but decreased by 3 percentage points since 1963. Regional variations exist in both the amount and kind of vacant land, suggesting that any ameliorative actions should be designed to fit specific conditions. Cities also reported that most vacant parcels are small, odd shaped, and disconnected, making them difficult to regenerate. Disinvestment, suburbanization and annexation are the primary causes of increases in vacant land supply while growing local economies, population in-migration, and city policies tend to help reduce the amount of vacant land. 相似文献
74.
Boettcher SW Berg SA Schierhorn M Strandwitz NC Lonergan MC Stucky GD 《Nano letters》2008,8(10):3404-3408
We demonstrate that ionic surface functionalization is well-suited for controlling the electrochemical charging of nanoparticle assemblies. Gold nanoparticles approximately 2 nm in diameter were functionalized with between 0 and approximately 3.3 cationic thiols per particle and the coupled motion of ions and electrons during redox cycling (charging) was followed in situ using an electrochemical quartz-crystal microbalance. When the electrochemistry is performed using a polycation electrolyte too large to penetrate the nanoparticle film, the degree of reduction possible was found to be dictated by the number of cationic ligands on the particle surface available for charge compensation. This route to reduced particles might be useful for electronic device fabrication, since the negative electronic charge is precisely compensated by immobile cationic ligands. 相似文献
75.
Boettcher SW Strandwitz NC Schierhorn M Lock N Lonergan MC Stucky GD 《Nature materials》2007,6(8):592-596
Interfaces between nanoscale and bulk electroactive materials are important for the design of electronic devices using solution-processed nanoparticles. We report that thin films of hexanethiolate-capped gold nanoparticles with a core diameter of 2.1+/-0.4 nm deposited onto n-InP wafers form Schottky contacts whose barrier height can be actively tuned from 0.27+/-0.03 to 1.11+/-0.09 eV by electrochemically adjusting the nanoparticle Fermi level. This result is remarkable because interfacial barriers at conventional metal-semiconductor contacts are largely insensitive to the initial Fermi level of the metal. Furthermore, it highlights two general features of solution-processed nanoparticle assemblies in comparison with traditional bulk electronic materials: (1) the ability of ions to permeate the nanoparticle assembly enables the electrochemical injection of charges and hence active control of the Fermi level, and (2) ligand passivation of nanoparticle surfaces prevents interfacial reactions with the semiconductor that could otherwise lead to strong Fermi-level pinning. 相似文献
76.
Guimaraes MP Wong DK Uy ET Grosenick L Suppes P 《IEEE transactions on bio-medical engineering》2007,54(3):436-443
While magnetoencephalography (MEG) is widely used to identify spatial locations of brain activations associated with various tasks, classification of single trials in stimulus-locked experiments remains an open subject. Very significant single-trial classification results have been published using electroencephalogram (EEG) data, but in the MEG case, the weakness of the magnetic fields originating from the relevant sources relative to external noise, and the high dimensionality of the data are difficult obstacles to overcome. We present here very significant MEG single-trial mean classification rates of words. The number of words classified varied from seven to nine and both visual and auditory modalities were studied. These results were obtained by using a variety of blind sources separation methods: spatial principal components analysis (PCA), Infomax independent components analysis (Infomax ICA) and second-order blind identification (SOBI). The sources obtained were classified using two methods, linear discriminant classification (LDC) and v-support vector machine (v-SVM). The data used here, auditory and visual presentations of words, presented nontrivial classification problems, but with Infomax ICA associated with LDC we obtained high classification rates. Our best single-trial mean classification rate was 60.1% for classification of 900 single trials of nine auditory words. On two-class problems rates were as high as 97.5%. 相似文献
77.
Yifeng Shi Chunxiu Hua Bin Li Xiangpeng Fang Chaohua Yao Yichi Zhang Yong‐Sheng Hu Zhaoxiang Wang Liquan Chen Dongyuan Zhao Galen D. Stucky 《Advanced functional materials》2013,23(14):1832-1838
Highly ordered mesoporous crystalline MoSe2 is synthesized using mesoporous silica SBA‐15 as a hard template via a nanocasting strategy. Selenium powder and phosphomolybdic acid (H3PMo12O40) are used as Se and Mo sources, respectively. The obtained products have a highly ordered hexagonal mesostructure and a rod‐like particle morphology, analogous to the mother template SBA‐15. The UV‐vis‐NIR spectrum of the material shows a strong light absorption throughout the entire visible wavelength region. The direct bandgap is estimated to be 1.37 eV. The high surface area MoSe2 mesostructure shows remarkable photocatalytic activity for the degradation of rhodamine B, a model organic dye, in aqueous solution under visible light irradiation. In addition, the synthesized mesoporous MoSe2 possess a reversible lithium storage capacity of 630 mAh g?1 for at least 35 cycles without any notable decrease. The rate performance of mesoporous MoSe2 is much better than that of analogously synthesized mesoporous MoS2, making it a promising anode for the lithium ion battery. 相似文献
78.
Many urban areas affected by flood disasters are also becoming increasingly ecologically and socially fragmented due to the accumulation of vacant properties. While redevelopment is often viewed as the primary objective in regenerating vacant properties, they can also potentially provide ecological and hydrological land uses. Rather than chasing developmentbased incentives for regenerating vacant lots in high flood-risk communities, a balance should be sought between new developmental land uses and green infrastructure to help counteract stormwater runoff and flood effects, or “Resilience through Regeneration.” This paper uses landscape performance measures to evaluate the economic and hydrologic performance of green infrastructure regeneration projects for three marginalized neighborhoods in Houston, Texas, USA. Each project site is characterized by excessive vacant lots and flood issues. Results suggest that, when using green infrastructure to regenerate vacant properties, 1) flood risk continually decreases, 2) upfront economic costs increase in the short term (when compared to conventional development), and 3) the long-term economic return on investment is much higher. 相似文献
79.
This article examines the future role of energy efficiency as a resource in the Western US and Canada, as envisioned in the
most recent resource plans issued by 16 utilities, representing about 60% of the region’s load. Utility and third-party-administered
energy-efficiency programs proposed by 15 utilities over a 10-year horizon would save almost 19,000 GWh annually, about 5.2%
of forecast load. There are clear regional trends in the aggressiveness of proposed energy savings. California’s investor-owned
utilities (IOUs) had the most aggressive savings targets, followed by IOUs in the Pacific Northwest, and the lowest savings
were proposed by utilities in Inland West states and by two public utilities on the West Coast. The adoption of multiple,
aggressive policies targeting energy efficiency and climate change appears to produce sizeable energy-efficiency commitments.
Certain specific policies, such as mandated energy savings goals for California’s IOUs and energy-efficiency provisions in
Nevada’s Renewable Portfolio Standard, had a direct impact on the level of energy savings included in the resource plans.
Other policies, such as revenue decoupling and shareholder incentives and voluntary or legislatively mandated greenhouse gas
emission reduction policies, may have also impacted utilities’ energy-efficiency commitments, though the effects of these
policies are not easily measured. Despite progress among the utilities in our sample, more aggressive energy-efficiency strategies
that include high-efficiency standards for additional appliances and equipment, tighter building codes for new construction
and renovation, as well as more comprehensive ratepayer-funded energy-efficiency programs are likely to be necessary to achieve
a region-wide goal of meeting 20% of electricity demand with efficiency in 2020.
相似文献
Charles GoldmanEmail: |
80.
Nathan M. Anderson Susanne E. Keller Niharika Mishra Shannon Pickens Dana Gradl Tim Hartter Galen Rokey Christopher Dohl Brian Plattner Stuart Chirtel Elizabeth M. Grasso‐Kelley 《Journal of food science》2017,82(3):738-743
Little research exists on Salmonella inactivation during extrusion processing, yet many outbreaks associated with low water activity foods since 2006 were linked to extruded foods. The aim of this research was to study Salmonella inactivation during extrusion of a model cereal product. Oat flour was inoculated with Salmonella enterica serovar Agona, an outbreak strain isolated from puffed cereals, and processed using a single‐screw extruder at a feed rate of 75 kg/h and a screw speed of 500 rpm. Extrudate samples were collected from the barrel outlet in sterile bags and immediately cooled in an ice–water bath. Populations were determined using standard plate count methods or a modified most probable number when populations were low. Reductions in population were determined and analyzed using a general linear model. The regression model obtained for the response surface tested was Log (NR/NO) = 20.50 + 0.82T ? 141.16aw – 0.0039T2 + 87.91aw2 (R2 = 0.69). The model showed significant (p < 0.05) linear and quadratic effects of aw and temperature and enabled an assessment of critical control parameters. Reductions of 0.67 ± 0.14 to 7.34 ± 0.02 log CFU/g were observed over ranges of aw (0.72 to 0.96) and temperature (65 to 100 °C) tested. Processing conditions above 82 °C and 0.89 aw achieved on average greater than a 5‐log reduction of Salmonella. Results indicate that extrusion is an effective means for reducing Salmonella as most processes commonly employed to produce cereals and other low water activity foods exceed these parameters. Thus, contamination of an extruded food product would most likely occur postprocessing as a result of environmental contamination or through the addition of coatings and flavorings. 相似文献