نتایج جستجو برای: روش xrf

تعداد نتایج: 372314  

Journal: : 2022

هدف: هدف از این پژوهش بررسی واسطه‌­ای راهبردهای سازش نایافته تنظیم شناختی هیجان در رابطه باورهای فراشناختی با اضطراب امتحان بود. روش: روش حاضر توصیفی و نوع همبستگی جامعه آماری را کلیه دانش‌­آموزان پسر دوره دوم متوسطه شهر تهران سال تحصیلی 1401-1400 تشکیل دادند که تعداد 456 نفر به نمونه‏‌گیری دسترس انتخاب شرکت کردند. ابزارها شامل سیاهه ابوالقاسمی همکاران (1375)، پرسشنامه باکو دیگران (2009)، فرم ک...

2018
Fang Li Jihua Wang Li Xu Songxue Wang Minghui Zhou Jingwei Yin Anxiang Lu

The accuracy, repeatability and detection limits of the energy-dispersive X-ray fluorescence (XRF) spectrometer used in this study were tested to verify its suitability for rapid screening of cadmium in samples. Concentrations of cadmium in rice grain samples were tested by the XRF spectrometer. The results showed that the apparatus had good precision around the national limit value (0.2 mg/kg)...

2012
Marie Hansson Helena Filipsson Nyström Svante Jansson Jukka Lausmaa Gertrud Berg

Patients with Graves' disease can be medically prepared before surgery in different ways, which may have various effects on iodine stores. Thyroid specimens were collected at surgery from two patients pretreated with propylthiouracil (PTU) and stable iodine, respectively. A quantitative analysis of iodine content was performed using X-ray fluorescence (XRF) in frozen tissue and a qualitative an...

2011
A. N. RINALDONI M. E. CAMPDERRÓS A. PÉREZ PADILLA E. PERINO J. E. FERNÁNDEZ

The application of ultrafiltration for milk concentration allows obtaining a raw material for yoghurt elaboration, with total solids increased. The products have special characteristics due to different ratios proteins/lactose can be obtained, as well as they have nutritional properties with beneficial effects in human health. In this study the content of calcium, potassium, phosphorous, iron, ...

2000
M. Bos

Neural networks are shown to be useful as emplncal mathematical models m the calculation of quantltatlve analytical results, gvmg sufflclent accuracy to compete successfully with various common cahbratlon procedures. The performance of these neural-network models for cahbratlon data from x-ray fluorescence spectrometry (XRF) was evaluated for two trammg methods, 1 e , backward error propagation...

2008
Richard Myers Noah Kolodziejski Michael Squillante Richard A. Myers Noah J. Kolodziejski Michael R. Squillante

A study was undertaken to determine if laser-induced breakdown spectroscopy (LIBS) can be a practical and competitive alternative to X-ray fluorescence (XRF) methods for lead-in-paint inspection. Experiments in the laboratory confirmed that LIBS is suitable for detecting lead in paint at the hazard levels defined by federal agencies. Although we compared speed, function and cost, fundamental di...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم کشاورزی و منابع طبیعی گرگان - دانشکده علوم کشاورزی 1390

فرسایش و رسوبگذاری مسأله ایست که امروزه در ایران و جهان مشکلات زیادی را به دنبال دارد. از جمله این مشکلات پر شدن مخازن سد ها در اثر رسوبهایی که توسط رودخانه ها حمل می شوند و همچنین آلودگی منابع آبی در اثر رسوباتی که مواد شیمیایی مضری با خود حمل می کنند، می باشد. برای مقابله با این مشکل از گذشته تا کنون راهکارهای زیادی مورد استفاده قرار گرفته است. در چند دهه ی اخیر روشی با عنوان منشأیابی یا انگش...

2005
A. M. Soderberg S. R. Kulkarni B. P. Schmidt R. C. Smith P. R. Wood

We present the results from a Hubble Space Telescope/ACS study of the supernovae associated with gamma-ray bursts 040924 (z = 0.86) and 041006 (z = 0.71). We find evidence that both GRBs were associated with a SN1998bw-like supernova dimmed by ∼ 1.5 and ∼ 0.3 magnitudes, respectively, making GRB040924 the faintest GRB-associated SN ever detected. We study the luminosity dispersion in GRB/XRF-as...

2004
Maria Helena Santos Marise de Oliveira Herman Sander Mansur Wander Luiz Vasconcelos

Several techniques have been utilized for the preparation of hydroxyapatite (HA) and other calcium phosphates for the development of biomaterials. It is vital to know the reaction kinetics to be able to control the material obtained by the aqueous solution route. In the present work, HA has been produced by different wet precipitation processes and different experimental conditions. Calcium hyd...

2005
J. Greiner

An important parameter for the distinction of X-ray flashes, X-ray rich bursts and Gamma-ray bursts in the rest frame is the distance to the explosion site. Here we report on the spectroscopic redshift determination of the host galaxy of XRF/GRB 030528 using the ESO VLT FORS2 instrument. From the strong oxygen and hydrogen emission lines the redshift was measured to be z=0.782±0.001. Obtaining ...

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