A beam-stop mount designed for use with area detectors

2000 ◽  
Vol 33 (2) ◽  
pp. 415-416
Author(s):  
Alexander Bertok ◽  
John W. Allen Jr ◽  
Wen-jeng Li ◽  
Steven Sheriff
Keyword(s):  

A beam-stop holder is described that allows for easy removal of the beam stop during alignment and calibration measurements and then for precise repositioning prior to data collection.

2016 ◽  
Vol 71 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Christian G. Reuter ◽  
Yury V. Vishnevskiy ◽  
Sebastian Blomeyer ◽  
Norbert W. Mitzel

AbstractA number of measures to increase the quality of data recorded with an improved Balzers Eldigraph KD-G2 gas-phase electron diffractometer are discussed. The beam-stop has been decoupled from the sector enabling us recording the current of the primary beam and scattered electrons during the experiment. Different beam-stops were tested for use in the present setup. Modifications of the nozzle tip of an earlier described medium temperature nozzle are reported. The measures lead to reduced exposure times and reduced amount of sample necessary for complete data collection.


Author(s):  
S.W. Hui ◽  
D.F. Parsons

The development of the hydration stages for electron microscopes has opened up the application of electron diffraction in the study of biological membranes. Membrane specimen can now be observed without the artifacts introduced during drying, fixation and staining. The advantages of the electron diffraction technique, such as the abilities to observe small areas and thin specimens, to image and to screen impurities, to vary the camera length, and to reduce data collection time are fully utilized. Here we report our pioneering work in this area.


Author(s):  
Wah Chi

Resolution and contrast are the important factors to determine the feasibility of imaging single heavy atoms on a thin substrate in an electron microscope. The present report compares the atom image characteristics in different modes of fixed beam dark field microscopy including the ideal beam stop (IBS), a wire beam stop (WBS), tilted illumination (Tl) and a displaced aperture (DA). Image contrast between one Hg and a column of linearly aligned carbon atoms (representing the substrate), are also discussed. The assumptions in the present calculations are perfectly coherent illumination, atom object is represented by spherically symmetric potential derived from Relativistic Hartree Fock Slater wave functions, phase grating approximation is used to evaluate the complex scattering amplitude, inelastic scattering is ignored, phase distortion is solely due to defocus and spherical abberation, and total elastic scattering cross section is evaluated by the Optical Theorem. The atom image intensities are presented in a Z-modulation display, and the details of calculation are described elsewhere.


Author(s):  
Weiping Liu ◽  
Jennifer Fung ◽  
W.J. de Ruijter ◽  
Hans Chen ◽  
John W. Sedat ◽  
...  

Electron tomography is a technique where many projections of an object are collected from the transmission electron microscope (TEM), and are then used to reconstruct the object in its entirety, allowing internal structure to be viewed. As vital as is the 3-D structural information and with no other 3-D imaging technique to compete in its resolution range, electron tomography of amorphous structures has been exercised only sporadically over the last ten years. Its general lack of popularity can be attributed to the tediousness of the entire process starting from the data collection, image processing for reconstruction, and extending to the 3-D image analysis. We have been investing effort to automate all aspects of electron tomography. Our systems of data collection and tomographic image processing will be briefly described.To date, we have developed a second generation automated data collection system based on an SGI workstation (Fig. 1) (The previous version used a micro VAX). The computer takes full control of the microscope operations with its graphical menu driven environment. This is made possible by the direct digital recording of images using the CCD camera.


1997 ◽  
Vol 6 (4) ◽  
pp. 34-47 ◽  
Author(s):  
Steven H. Long ◽  
Lesley B. Olswang ◽  
Julianne Brian ◽  
Philip S. Dale

This study investigated whether young children with specific expressive language impairment (SELI) learn to combine words according to general positional rules or specific, grammatic relation rules. The language of 20 children with SELI (4 females, 16 males, mean age of 33 months, mean MLU of 1.34) was sampled weekly for 9 weeks. Sixteen of these children also received treatment for two-word combinations (agent+action or possessor+possession). Two different metrics were used to determine the productivity of combinatorial utterances. One metric assessed productivity based on positional consistency alone; another assessed productivity based on positional and semantic consistency. Data were analyzed session-by-session as well as cumulatively. The results suggest that these children learned to combine words according to grammatic relation rules. Results of the session-by-session analysis were less informative than those of the cumulative analysis. For children with SELI ready to make the transition to multiword utterances, these findings support a cumulative method of data collection and a treatment approach that targets specific grammatic relation rules rather than general word combinations.


2019 ◽  
Vol 4 (2) ◽  
pp. 356-362
Author(s):  
Jennifer W. Means ◽  
Casey McCaffrey

Purpose The use of real-time recording technology for clinical instruction allows student clinicians to more easily collect data, self-reflect, and move toward independence as supervisors continue to provide continuation of supportive methods. This article discusses how the use of high-definition real-time recording, Bluetooth technology, and embedded annotation may enhance the supervisory process. It also reports results of graduate students' perception of the benefits and satisfaction with the types of technology used. Method Survey data were collected from graduate students about their use and perceived benefits of advanced technology to support supervision during their 1st clinical experience. Results Survey results indicate that students found the use of their video recordings useful for self-evaluation, data collection, and therapy preparation. The students also perceived an increase in self-confidence through the use of the Bluetooth headsets as their supervisors could provide guidance and encouragement without interrupting the flow of their therapy sessions by entering the room to redirect them. Conclusions The use of video recording technology can provide opportunities for students to review: videos of prospective clients they will be treating, their treatment videos for self-assessment purposes, and for additional data collection. Bluetooth technology provides immediate communication between the clinical educator and the student. Students reported that the result of that communication can improve their self-confidence, perceived performance, and subsequent shift toward independence.


ASHA Leader ◽  
2009 ◽  
Vol 14 (4) ◽  
pp. 7-28
Author(s):  
Jaumeiko Brown
Keyword(s):  

2008 ◽  
Vol 18 (2) ◽  
pp. 87-98 ◽  
Author(s):  
Vinciya Pandian ◽  
Thai Tran Nguyen ◽  
Marek Mirski ◽  
Nasir Islam Bhatti

Abstract The techniques of performing a tracheostomy has transformed over time. Percutaneous tracheostomy is gaining popularity over open tracheostomy given its advantages and as a result the number of bedside tracheostomies has increased necessitating the need for a Percutaneous Tracheostomy Program. The Percutaneous Tracheostomy Program at the Johns Hopkins Hospital is a comprehensive service that provides care to patients before, during, and after a tracheostomy with a multidisciplinary approach aimed at decreasing complications. Education is provided to patients, families, and health-care professionals who are involved in the management of a tracheostomy. Ongoing prospective data collection serves as a tool for Quality Assurance.


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