Improvement of charge resolution for high Z/β particles in CR-39 nuclear track detectors by means of two-step etching technique

2012 ◽  
Vol 274 ◽  
pp. 36-41 ◽  
Author(s):  
S. Kodaira ◽  
S. Naka ◽  
N. Yasuda ◽  
H. Kawashima ◽  
M. Kurano ◽  
...  
Keyword(s):  
Etching Technique ◽  
Nuclear Track Detectors ◽  
Charge Resolution

The Formation, Structure, Distribution and Frequency of Nuclear Pores

1971 ◽  
Vol 29 ◽  
pp. 518-519
Author(s):  
G. G. Maul
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Dynamic Structure ◽  
Nuclear Pore ◽  
Nuclear Pores ◽  
Filter Function ◽  
Etching Technique ◽  
Selective Filter ◽  
Membranous Part

The chromatin of eukaryotic cells is separated from the cytoplasm by a double membrane. One obvious structural specialization of the nuclear membrane is the presence of pores which have been implicated to facilitate the selective nucleocytoplasmic exchange of a variety of large molecules. Thus, the function of nuclear pores has mainly been regarded to be a passive one. Non-membranous diaphragms, radiating fibers, central rings, and other pore-associated structures were thought to play a role in the selective filter function of the nuclear pore complex. Evidence will be presented that suggests that the nuclear pore is a dynamic structure which is non-randomly distributed and can be formed during interphase, and that a close relationship exists between chromatin and the membranous part of the nuclear pore complex.Octagonality of the nuclear pore complex has been confirmed by a variety of techniques. Using the freeze-etching technique, it was possible to show that the membranous part of the pore complex has an eight-sided outline in human melanoma cells in vitro. Fibers which traverse the pore proper at its corners are continuous and indistinguishable from chromatin at the nucleoplasmic side, as seen in conventionally fixed and sectioned material. Chromatin can be seen in octagonal outline if serial sections are analyzed which are parallel but do not include nuclear membranes (Fig. 1). It is concluded that the shape of the pore rim is due to fibrous material traversing the pore, and may not have any functional significance. In many pores one can recognize a central ring with eight fibers radiating to the corners of the pore rim. Such a structural arrangement is also found to connect eight ribosomes at the nuclear membrane.

Structures Formed by Cryoprotective Agents Used in Freezc-Etching

1971 ◽  
Vol 29 ◽  
pp. 448-449
Author(s):  
G. G. Cocks ◽  
C. E. Cluthe
Keyword(s):  
Aqueous Solution ◽  
Polyethylene Oxide ◽  
Liquid Nitrogen Temperature ◽  
Ice Crystals ◽  
Etching Technique ◽  
Structural Constituent ◽  
Cryoprotective Agents ◽  
Quick Freezing ◽  
Freeze Etching ◽  
Fractured Surface

The freeze etching technique is potentially useful for examining dilute solutions or suspensions of macromolecular materials. Quick freezing of aqueous solutions in Freon or propane at or near liquid nitrogen temperature produces relatively large ice crystals and these crystals may damage the structures to be examined. Cryoprotective agents may reduce damage to the specimem, hut their use often results in the formation of a different set of specimem artifacts.In a study of the structure of polyethylene oxide gels glycerol and sucrose were used as cryoprotective agents. The experiments reported here show some of the structures which can appear when these cryoprotective agents are used.Figure 1 shows a fractured surface of a frozen 25% aqueous solution of sucrose. The branches of dendritic ice crystals surrounded hy ice-sucrose eutectic can be seen. When this fractured surface is etched the ice in the dendrites sublimes giving the type of structure shown in Figure 2. The ice-sucrose eutectic etches much more slowly. It is the smooth continuous structural constituent surrounding the branches of the dendrites.

High-purity Ge x-ray detectors: Sensitivity factors and usefulness

1990 ◽  
Vol 48 (2) ◽  
pp. 548-548
Author(s):  
E. B. Steel
Keyword(s):  
High Purity ◽  
High Energy ◽  
Quantitative Chemical Analysis ◽  
Detector Performance ◽  
X Ray ◽  
Detector Sensitivity ◽  
Specimen Holder ◽  
Many Instruments ◽  
Charge Resolution ◽  
Sensitivity Factors

High Purity Germanium (HPGe) x-ray detectors are now commercially available for the analytical electron microscope (AEM). The detectors have superior efficiency at high x-ray energies and superior resolution compared to traditional lithium-drifted silicon [Si(Li)] detectors. However, just as for the Si(Li), the use of the HPGe detectors requires the determination of sensitivity factors for the quantitative chemical analysis of specimens in the AEM. Detector performance, including incomplete charge, resolution, and durability has been compared to a first generation detector. Sensitivity factors for many elements with atomic numbers 10 through 92 have been determined at 100, 200, and 300 keV. This data is compared to Si(Li) detector sensitivity factors.The overall sensitivity and utility of high energy K-lines are reviewed and discussed. Many instruments have one or more high energy K-line backgrounds that will affect specific analytes. One detector-instrument-specimen holder combination had a consistent Pb K-line background while another had a W K-line background.

Controllable end shape modification of ZnO nano-arrays/rods by a simple wet chemical etching technique

2015 ◽  
Vol 48 (36) ◽  
pp. 365303 ◽  
Author(s):  
Jingchang Sun ◽  
Ting Zhao ◽  
Zhangwei Ma ◽  
Ming Li ◽  
Cheng Chang ◽  
...  
Keyword(s):  
Chemical Etching ◽  
Shape Modification ◽  
Etching Technique ◽  
Wet Chemical ◽  
Wet Chemical Etching

A study of indoor radon levels in rural dwellings of Ezine (Canakkale, Turkey) using solid-state nuclear track detectors

2008 ◽  
Vol 131 (3) ◽  
pp. 379-384 ◽  
Author(s):  
Y. Orgun ◽  
N. Altinsoy ◽  
S. Y. Sahin ◽  
B. Ataksor ◽  
N. Celebi
Keyword(s):  
Solid State ◽  
Indoor Radon ◽  
Nuclear Track Detectors

scholarly journals Solar-blind ultraviolet photodetector based on vertically aligned single-crystalline β-Ga2O3 nanowire arrays

Nanophotonics ◽  
2020 ◽  
Vol 9 (15) ◽  
pp. 4497-4503
Author(s):  
Liying Zhang ◽  
Xiangqian Xiu ◽  
Yuewen Li ◽  
Yuxia Zhu ◽  
Xuemei Hua ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Light Trapping ◽  
High Surface ◽  
Volume Ratio ◽  
Average Diameter ◽  
Nanowire Arrays ◽  
Etching Technique ◽  
Inductively Coupled ◽  
Solar Blind ◽  
Vertically Aligned

AbstractVertically aligned nanowire arrays, with high surface-to-volume ratio and efficient light-trapping absorption, have attracted much attention for photoelectric devices. In this paper, vertical β-Ga2O3 nanowire arrays with an average diameter/height of 110/450 nm have been fabricated by the inductively coupled plasma etching technique. Then a metal-semiconductor-metal structured solar-blind photodetector (PD) has been fabricated by depositing interdigital Ti/Au electrodes on the nanowire arrays. The fabricated β-Ga2O3 nanowire PD exhibits ∼10 times higher photocurrent and responsivity than the corresponding film PD. Moreover, it also possesses a high photocurrent to dark current ratio (Ilight/Idark) of ∼104 and a ultraviolet/visible rejection ratio (R260 nm/R400 nm) of 3.5 × 103 along with millisecond-level photoresponse times.

scholarly journals Effectiveness of a Selective Etching Technique in Reducing White Spots Formation around Lingual Brackets: A Prospective Cohort Clinical Study

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 572
Author(s):  
Domenico Dalessandri ◽  
Marino Bindi ◽  
Francesca Massetti ◽  
Gaetano Isola ◽  
Marco Migliorati ◽  
...  
Keyword(s):  
Clinical Study ◽  
Difficulty Level ◽  
Prospective Clinical Study ◽  
White Spot Lesions ◽  
Etching Technique ◽  
White Spots ◽  
Accumulation Index ◽  
One Year ◽  
Lingual Brackets ◽  
And Control

The risk of developing white spot lesions (WSLs) after orthodontic treatment with lingual brackets is generally considered lower than with labial ones, even if plaque accumulation is frequently higher due to the increased difficulty level in oral hygiene maintenance. In this prospective clinical study, selective enamel etching technique effectiveness in reducing plaque accumulation and WSLs was tested. Thirty patients were bonded with a split-mouth approach: two randomly selected opposite quadrants were used as the test sides, using customized plastic etching guides, and the other two as control sides, applying traditional direct etching methods. The plaque presence around the braces was recorded after 1, 3, 6, and 12 months according to a lingual plaque accumulation index (LPAI), as was the presence of WSLs. PAI measured values were significantly higher in the control sides during the observation period. Test and control sides differed significantly for new WSL onset only after 12 months of treatment. Therefore, the present research demonstrated that this guided enamel etching technique allowed for significant reduction in plaque accumulation around the lingual brackets and reduced onset of white spots after one year of treatment.

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