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A Brief Primer on the legendre Transformation

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Journal of Applied Mathematics and Physics 2023年第11期11卷 3505-3518页

作者： Steven J. Kilner David l. Farnsworth Department of Mathematics Monroe Community College Rochester USA School of Mathematics and Statistics Rochester Institute of Technology Rochester USA

Guidance is offered for understanding and using the legendre transformation and its associated duality among functions and curves. The genesis of this paper was encounters with colleagues and students asking about the transformation. A main feature is simplicity of exposition, while keeping in mind the purpose or application for using the transformation.

关键词： legendre Transformation Dual Curve Reflectivity line of Support Tangent line

Oxbow lakes as Geological Archives of Historical Changes in Channel Substrate, Swan Creek, Toledo, Ohio (USA)

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Open Journal of Modern Hydrology 2022年第2期12卷 32-54页

作者： Jocelyn l. Hicks James E. Evans Department of Geology School of Earth Environment and Society Bowling Green State University Bowling Green OH USA

Efforts to restore urban rivers require an understanding of human-influenced changes in channel substrates. This study uses three naturally-occurring oxbows in a 3.5 km reach of Swan Creek, flowing through the City of Toledo, Ohio (USA) to reconstruct historical changes in channel substrate. Human impacts in the watershed were: 1) land clearance for agriculture (peaking in 1900-1920) and for suburban housing tracts (peaking in 1945-1970), followed by 2) the post-1940 creation of more efficient urban run-off systems from streets, parking lots, housing developments, and shopping centers. Historical aerial photographs and maps from 1935, 1940, 1950, 1963, 1974, and 1994 were georeferenced using ground control points, input to ArcGIS, and have root mean square error (RMSE) ranging from 0.19 - 0.77 m (average RMSE = 0.47 ± 0.20 m) when compared to the 2006 digital ortho quarter-quadrangle (DOQQ) image used as the basis for comparison. Results showed that channel sinuosity continually increased from 1.88 (1935) to 1.99 (2006). Two oxbows probably formed in 1913, and the third formed in 1940. Sediment cores and trenches were used to recognize historical channel substrates. Age control was provided by 14C geochronology and labels on food packaging materials found in flood layers. Grain-size analysis of channel substrates shows a historical coarsening-upward trend: the largest clast size interval (f5) changes from +0.78f in pre-1935 channels, to -1.15f in pre-1940 channels, to -1.69f in the 2006 channel. These results indicate recent urban runoff created fluvial pavements and increasing channel mobility as the stream removes legacy sediment from intrabasinal sediment storage.

关键词： Oxbows Channel Substrate legacy Sediment Anthropogenic Change Sediment Budget

Time Dependant Weld Shape in Ar-O_2 Shielded Stationary GTA Welding

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Journal of Materials Science & Technology 2007年第5期23卷 650-654页

作者： Shanping l U Dianzhong lI Hidetoshi Fujii Kiyoshi Nogi Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 Chian Joining and Welding Research Institute Osaka University Osaka567-0047 Japan

The stationary gas tungsten arc welding （GTA） is carried out on SUS304 stainless steel under Ar-0.1%O2 and Ar-0.3%O2 mixed shielding to observe the evolution of the molten pool and investigate the role of Marangoni convection on the weld shape. After welding, the oxygen content in the weld metal was measured by using an oxygen/nitrogen analyzer. Small addition of oxygen to the argon based shielding gas can effectively adjust the weld pool oxygen content. Oxygen plays an important role as an surface active element in determining the pattern of Marangoni convection in the stainless steel weld pool. When the weld metal oxygen content is over the critical value, 0.01 wt pct, corresponding to the Ar-0.3%O2 mixed shielding gas, the Marangoni convection changes from outward to inward direction and the weld shape dramatically changes from wide shallow shape to narrow deep shape.

关键词： Marangoni convection Oxygen Weld shape

Carbon stock and rate of carbon sequestration in Dipterocarpus forests of Manipur,Northeast India

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Journal of Forestry Research 2015年第2期26卷 315-322页

作者： l.Supriya Devi P.S.Yadava Department of life Sciences Manipur University

We examined the carbon stock and rate of carbon sequestration in a tropical deciduous forest dominated by Dipterocarpus tuberculatus in Manipur,North East *** of aboveground biomass was determined by harvest method and multiplied with density of tree *** aboveground biomass was between18.27–21.922 t ha-1and the carbon stock ranged from9.13 to 10.96 t C ha-1across forest *** biomass and carbon stock increased with the increase in tree *** rate of carbon sequestration varied from1.4722 to 4.64136 t ha-1year-1among the dominant tree species in forest stands in tropical deciduous forest *** rate of carbon sequestration depends on species composition,the density of large trees in different girth classes,and anthropogenic disturbances in the present forest *** work is required to identify tree species having the highest potential to sequester CO2 from the atmosphere,which could lead to recommendations for tree plantations in a degraded ecosystem.

关键词： Carbon budget Carbon sequestration Dipterocarpus Biomass Net production

EFFECT OF ElECTROlESS DEPOSITION CONDITIONS ON THE STRUCTURES AND THE MAGNETIC PERFORMANCES OF THE Co-Fe-P AllOY

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Acta Metallurgica Sinica(English letters) 2006年第4期19卷 307-312页

作者： S.l. Wang F.Q. Zeng Department of Applied Chemistry College of Materials Science and Engineering Huaqiao University Quanzhou 362021 China

Electroless Co-Fe-P alloys were deposited from an alkaline bath, containing boric acid as a buffer agent and sodium citrate as a complexing agent. As a result, with the increase of pH of the bath, the iron content of the deposit increased, whereas the cobalt and phosphorus contents decreased. The structure of the deposit was investigated using X-ray diffraction （XRD） and transmission electron microscope （TEM）. The deposit consisted of hexahedron phase Co, cubic phase Fe-Co, and amorphous phase （crystalline）. The magnetic performances of the deposit were studied using vibrating sample magnetometer （VSM）. The more the content of Fe and the less the content of P （the content of Co being less）, the better the magnetic performances of the deposit. The Co-Fe-P deposit was suitable for use as soft magnetic material.

关键词： electroless deposition Co-Fe-P structure magnetic performance

Probability Models with Discrete and Continuous Parts

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Open Journal of Statistics 2022年第1期12卷 82-97页

作者： James E. Marengo David l. Farnsworth School of Mathematical Sciences Rochester Institute of Technology Rochester New York USA

In mathematical statistics courses, students learn that the quadratic function is minimized when x is the mean of the random variable X, and that the graphs of this function for any two distributions of X are simply translates of each other. We focus on the problem of minimizing the function defined by in the context of mixtures of probability distributions of the discrete, absolutely continuous, and singular continuous types. This problem is important, for example, in Bayesian statistics, when one attempts to compute the decision function, which minimizes the expected risk with respect to an absolute error loss function. Although the literature considers this problem, it does so only under restrictive conditions on the distribution of the random variable X, by, for example, assuming that the corresponding cumulative distribution function is discrete or absolutely continuous. By using Riemann-Stieltjes integration, we prove a theorem, which solves this minimization problem under completely general conditions on the distribution of X. We also illustrate our result by presenting examples involving mixtures of distributions of the discrete and absolutely continuous types, and for the Cantor distribution, in which case the cumulative distribution function is singular continuous. Finally, we prove a theorem that evaluates the function y(x) when X has the Cantor distribution.

关键词： Mixed-Type Distribution Function Riemann-Stieltjes Integration Median of a Random Variable Cantor Distribution

Experimental Investigation on Dual Wavelength High-Frequency Chaos Generation and Synchronization

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Chinese Physics letters 2005年第12期22卷 3029-3031页

作者：桑新柱余重秀王葵如 CHU Pak l. School of Electronic Engineering Beijing University of Posts and Telecommunications Beijing 100876 Optoelectronics Ftesearch Centre City University of Hong Kong Kowloon Hong Kong

Dual wavelength high-frequency chaos based on nonlinear effects is generated in an erbium-doped fibre ring laser, where tunable filters （TFs） are used to select the wavelength. A receiving fibre laser with an open-loop structure is constructed with identical parameters as the transmitting fibre laser. By tuning the TFs and the fibre delay line in the receiving fibre laser, chaos synchronization has been observed at anyone the two wavelengths after the chaos is transmitted over 1 km. It is of far reaching importance to construct the high capacity chaos communication system.

关键词： DOPED FIBER lASERS GENERAlIZED SYNCHRONIZATION RING lASERS DYNAMICS

Impact of COVID-19 pandemic on health-promoting lifestyle behaviors:A cross-sectional study

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Journal of Acute Disease 2023年第1期12卷 10-17,I0001-I0003页

作者： Çiğdem SamancıTekin Züleyha Kılıç NiğdeÖmer Halisdemir University Faculty of MedicineInternal Medical SciencesDepartment of Public HealthNiğdeTurkey NiğdeÖmer Halisdemir University Faculty of Health SciencesDepartment of Internal Diseases NursingNiğdeTurkey

Objective:To explore health-improving behaviors during COVID-19 pandemic and to reveal the impact of the risk perception of COVID-19 on these ***:We recruited a total of 510 participants for this cross-sectional *** data were collected online using a questionnaire booklet covering a form inquiring about the participants’demographic,physical,and mental characteristics,the Generalized Anxiety Disorder-7 Scale,and the COVID-19 Perceived Risk ***:The mean age of the participants was(28.7±10.1)years,and 76.1%were *** the participants,31.8%were overweight and *** 35.1%experienced negative alterations in their dietary patterns,23.9%reported positive changes to their diet during the ***,47.8%reported their sleep to be negatively affected during the *** the rate of those with extended screen time was 72.5%,it was 44.3%for the participants engaging in regular *** than one-third of the participants(35.9%)had high and severe *** also found increased risk perception of COVID-19 among females,obese,those with disturbed eating and sleep quality,healthcare workers,and those with severe ***:Overall,the pandemic has appeared to have brought both positive and negative impacts on maintaining and improving eating,sleep,physical activity,and mental health.

关键词： Health promotion Public health COVID-19 Generalized Anxiety Disorder-7 Scale Perceived Risk Scale Mental health Physical activity

Terbium-doped heavy metal glasses for green luminescence

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Journal of Rare Earths 2011年第12期29卷 1198-1200页

作者： l.Zur J.Pisarska W.A.Pisarski Institute of Chemistry University of Silesia

Compositional-dependent heavy metal lead borate glasses doped with Tb^3＋ ions were investigated. Green luminescence related to main ^5D4→^7F5 （543 nm） transition was registered under excitation of ^5D3 state of Tb^3＋ ions. Based on excitation and luminescence measurements, several spectroscopic parameters for Tb3＋ ions were examined as a function of heavy metal PbO content. luminescence decay analysis indicated that the ^5D4 luminescence lifetime of Tb^3＋ reduced from 2.83 to 1.42 ms, when PbO：B203 ratio was changed from 1：1 to 4：1.

关键词： glasses Tb^3+ ions excitation luminescence rare earths