scholarly journals Effect of Partial Dependence of Photopeak Data on The Calculations of NaI(Tl) Detector Spectrum

2019 ◽  
Vol 24 (1) ◽  
pp. 87
Author(s):  
Mahmoud Ahmad Elawi ◽  
Hafsa Taha Ahmad
Keyword(s):  
Excellent Agreement ◽  
Gaussian Distribution ◽  
Calibration Curve ◽  
Point Sources ◽  
Gaussian Shape ◽  
Total Data ◽  
Two Peaks ◽  
Compton Distribution ◽  
Partial Dependence ◽  
Detector Spectrum

Partial dependence of photopeak data of ɣ-ray energies is considering apart of peak channels after subtracting background (including Compton distribution) and obtaining symmetric Gaussian distribution, then considering this part to obtain other total data of peak. This was investigated by using NaI(Tl) detector with Eu-152, Ra-226 and Cs-137 point sources. For the isolated peaks of Eu-152, Gaussian shape is obtained, and the areas between ±σ and ±0.5σ were determined and efficiency is obtained. The calculated transformation to total data of peaks gave excellent agreement with the ordinary case. The overlap between the two peaks at 609.3 (Ra-226) and 661.6 keV (Cs-137) is studied with using σ values from data when sources are separated, and counts in peaks centroids. The data of each peak is "restored" and compared with that when sources are separated and gave a 98% agreement. Also the overlap between the two peaks at 1120 and 1238 keV (Ra-226) is studied with adopting the σ values from the shape calibration curve of Eu-152 and centroid counts in the same way as for the Ra-226 and Cs-137 case. The resultant peaks areas are compared with those obtained from efficiency calibration curve of Eu-152. However results here are of lower agreement.   http://dx.doi.org/10.25130/tjps.24.2019.014  

scholarly journals Polyethylene Gel Volume Fraction (Cross-linked Percentage) Measurement Using DSC Technique

2021 ◽  
Vol 10 (8) ◽  
pp. 114-115
Author(s):  
Shouresh Safaei
Keyword(s):  
Excellent Agreement ◽  
Calibration Curve ◽  
Volume Fraction ◽  
Continuous Process ◽  
Raw Material ◽  
Harmful Substances

In this paper, the measurement of the crosslinking percentage (gel volume fraction) of polyethylene materials by using DSC technique is presented. To obtain the calibration curve, the networked samples of ASTMD 2765-01 corresponding to the curves of pure melt samples at the start of the reaction were used. The resulting calibration curve was used to predict the percentage of polyethylene cross-linked in a continuous process, and these results were compared with those obtained from D 2765-01, which resulted in excellent agreement between the two states. This technique is faster and cheaper and requires less raw material, the product does not release any harmful substances and is ASTM correct.

scholarly journals 14C Ages of 43 Consecutive Single-Year Tree Rings Between 2710 and 2655 cal BP Using Accelerator Mass Spectrometry

Radiocarbon ◽  
2007 ◽  
Vol 49 (2) ◽  
pp. 459-464 ◽  
Author(s):  
Kayo Suzuki ◽  
Hirohisa Sakurai ◽  
Yui Takahashi ◽  
Shuichi Gunji ◽  
Fuyuki Tokanai ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tree Rings ◽  
Gaussian Distribution ◽  
Calibration Curve ◽  
Accelerator Mass Spectrometry ◽  
Linear Trend ◽  
Periodic Variation ◽  
Time Profile ◽  
Random Fluctuation ◽  
Statistical Accuracy

We have measured the radiocarbon ages of 43 consecutive single-year tree rings using accelerator mass spectrometry (AMS) with a statistical accuracy of ∼2.3%. AMS 14C ages of the 36 viable samples are between 2708 and 2666 cal BP, a period in which the Δ14C of the IntCal04 curve (Reimer et al. 2004) shows an enhancement. The 14C ages of the samples are scattered with a Gaussian distribution around the interpolated IntCal04 calibration curve. The time profile of the deviations of the 36 14C ages from the interpolated IntCal04 calibration curve indicates a linear trend and a characteristic variability rather than a random fluctuation around the curve. The trend indicates a higher gradient than that of the interpolated IntCal04 calibration curve. The profile implies a periodic variation of approximately 11 yr and an amplitude of roughly 18 14C yr.

Structure images of Si, Ge and Mos2 crystals and some application to radiation damage studies

1978 ◽  
Vol 36 (1) ◽  
pp. 292-293 ◽  
Author(s):  
K. Izui ◽  
T. Nishida ◽  
S. Furuno ◽  
H. Otsu ◽  
S. Kuwabara
Keyword(s):  
Radiation Damage ◽  
Exposure Time ◽  
Gaussian Distribution ◽  
Intensity Distribution ◽  
Chromatic Aberration ◽  
Magnetic Lens

Recently we have observed the structure images of silicon in the (110), (111) and (100) projection respectively, and then examined the optimum defocus and thickness ranges for the formation of such images on the basis of calculations of image contrasts using the n-slice theory. The present paper reports the effects of a chromatic aberration and a slight misorientation on the images, and also presents some applications of structure images of Si, Ge and MoS2 to the radiation damage studies.(1) Effect of a chromatic aberration and slight misorientation: There is an inevitable fluctuation in the amount of defocus due to a chromatic aberration originating from the fluctuations both in the energies of electrons and in the magnetic lens current. The actual image is a results of superposition of those fluctuated images during the exposure time. Assuming the Gaussian distribution for defocus, Δf around the optimum defocus value Δf0, the intensity distribution, I(x,y) in the image formed by this fluctuation is given by

Resistance Monitor and Control for Vacuum Evaporation of Metals and Carbon

1976 ◽  
Vol 34 ◽  
pp. 572-573
Author(s):  
Russell L. Steere ◽  
Eric F. Erbe ◽  
J. Michael Moseley
Keyword(s):  
Electronic Device ◽  
Point Sources ◽  
High Contrast ◽  
Variable Resistor ◽  
Quality Of Results ◽  
Low Contrast ◽  
Evaporation Source ◽  
And Control ◽  
At Will

We have designed and built an electronic device which compares the resistance of a defined area of vacuum evaporated material with a variable resistor. When the two resistances are matched, the device automatically disconnects the primary side of the substrate transformer and stops further evaporation.This approach to controlled evaporation in conjunction with the modified guns and evaporation source permits reliably reproducible multiple Pt shadow films from a single Pt wrapped carbon point source. The reproducibility from consecutive C point sources is also reliable. Furthermore, the device we have developed permits us to select a predetermined resistance so that low contrast high-resolution shadows, heavy high contrast shadows, or any grade in between can be selected at will. The reproducibility and quality of results are demonstrated in Figures 1-4 which represent evaporations at various settings of the variable resistor.

Preparation and Characterization of NH2-Terminal Fibrinogen Bβ Fragments from N-DSK of Human Fibrinogen

1984 ◽  
Vol 51 (01) ◽  
pp. 016-021 ◽  
Author(s):  
S Birken ◽  
G Agosto ◽  
B Lahiri ◽  
R Canfield
Keyword(s):  
High Performance ◽  
Gel Filtration ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Reverse Phase ◽  
Human Fibrinogen ◽  
Human Volunteers ◽  
Cnbr Cleavage ◽  
Two Peaks

SummaryIn order to investigate the early release of NH2-terminal plasmic fragments from the Bβ chain of fibrinogen, substantial quantities of Bβ 1-42 and Bβ 1-21 are required as immunogens, as radioimmunoassay standards and for infusion into human volunteers to determine the half-lives of these peptides. Towards this end methods that employ selective proteolytic cleavage of these fragments from fibrinogen have been developed. Both the N-DSK fragment, produced by CNBr cleavage of fibrinogen, and Bβ 1-118 were employed as substrates for plasmin with the finding of higher yields from N-DSK. Bβ 1-42 and Bβ 1-21 were purified by gel filtration and ion-exchange chromatography on SP-Sephadex using volatile buffers. When the purified preparation of Bβ 1-42 was chromatographed on reverse-phase high performance liquid chromatography, two peaks of identical amino acid composition were separated, presumably due either to pyroglutamate or to amide differences.

A Comparison of the Bethesda and New Oxford Methods of Factor VIII Antibody Assay

1982 ◽  
Vol 47 (01) ◽  
pp. 072-075 ◽  
Author(s):  
D E G Austen ◽  
K Lechner ◽  
C R Rizza ◽  
I L Rhymes
Keyword(s):  
Factor Viii ◽  
Excellent Agreement ◽  
International Committee ◽  
The Other ◽  
Antibody Assay ◽  
Collaborative Trial

SummaryA collaborative trial has been carried out under the auspices of the International Committee on Thrombosis and Haemostasis to compare the Bethesda and New Oxford methods of antibody assay. It was found that errors between laboratories were much greater than those within laboratories and each laboratory had a bias whereby it always rated samples high or low with respect to the other laboratories. However there was excellent agreement in the order in which laboratories ranked antibody samples and if a standard antibody sample could be provided there would be a significant improvement in numerical agreement between laboratories. On average, for this exercise, a result for a given sample in Bethesda units was 1.21 times the result in New Oxford units although it must be stressed that this ratio could vary from sample to sample.

COMPARISON OF VARIOUS METHODS FOR THE CHEMICAL ASSAY OF CORTICOIDS IN URINE

1955 ◽  
Vol 18 (4) ◽  
pp. 374-378
Author(s):  
Mogens Sprechler
Keyword(s):  
Calibration Curve ◽  
Periodic Acid ◽  
Reducing Power ◽  
Standard Technique ◽  
Phosphomolybdic Acid ◽  
Florisil Column ◽  
Chemical Assay ◽  
Chromatographic Procedure ◽  
Acid Reagent

SUMMARY Since 1949 about 10,000 urinary corticoid analyses have been performed routinely in our laboratory. The method used for this purpose was described in 1950 (Sprechler). We determine the corticoids which can be extracted from the urine with chloroform immediately after acidification to pH 1. The extract is washed with sodium hydroxide and water, a Girard separation is performed, and finally the reducing power of the ketonic fraction is measured by means of the phosphomolybdic acid reagent reaction. During the last few years two other chemical reactions have been used for comparison: The formaldehyde and the Porter-Silber method. After a thorough examination of the above methods a standard technique was followed. In the formaldehyde method a microdiffusion in a Conway unit was used instead of distillation of the formaldehyde following the oxidation with periodic acid. The calibration curve was corrected for loss of material by taking the standard doses of DOC through all the procedures of the method. A micromodification of the Porter-Silber method was chosen. Furthermore attempts were made to determine how specific the chromatographic procedure is in the determination of steroids in urinary extracts. For this purpose the Florisil column was used, and the technique described by Nelson & Samuels was followed. Finally we have investigated the glucuronide-bound corticoids in urine in a smaller series of objects.

Characterization of Microcrystalline Transition from Amorphous Silicon as a Function of Hydrogen Dilution and Substrate Temperature of Hot-wire CVD

2002 ◽  
Vol 715 ◽  
Author(s):  
Keda Wang ◽  
Haoyue Zhang ◽  
Jian Zhang ◽  
Jessica M. Owens ◽  
Jennifer Weinberg-Wolf ◽  
...  
Keyword(s):  
Substrate Temperature ◽  
Sudden Change ◽  
Chemical Vapor ◽  
Threshold Value ◽  
Ir Absorption ◽  
Sudden Increase ◽  
Hot Wire ◽  
Hydrogen Dilution ◽  
Integral Absorption ◽  
Two Peaks

Abstracta-Si:H films were prepared by hot wire chemical vapor deposition. One group was deposited at a substrate temperature of Ts=250°C with varied hydrogen-dilution ratio, 0<R<10; the other group was deposited with fixed R=3 but a varied Ts from 150 to 550°C. IR, Raman and PL spectra were studied. The Raman results indicate that there is a threshold value for the microstructure transition from a- to μc-Si. The threshold is found to be R ≈ 2 at Ts = 250°C and Ts ≈ 200°C at R=3. The IR absorption of Si-H at 640 cm-1 was used to calculate the hydrogen content, CH. CH decreased monotonically when either R or Ts increased. The Si-H stretching mode contains two peaks at 2000 and 2090 cm-1. The ratio of the integral absorption peaks I2090/(I2090+I2090) showed a sudden increase at the threshold of microcrystallinity. At the same threshold, the PL features also indicate a sudden change from a- to μc-Si., i.e. the low energy PL band becomes dominant and the PL total intensity decreases. We attribute the above IR and PL changes to the contribution of microcrystallinity, especially the c-Si gain-boundaries.

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