Optical stimulator for vision-based sensors

2014 ◽  
Vol 3 (2) ◽  
Author(s):  
Dirk Roessler ◽  
David A.K. Pedersen ◽  
Mathias Benn ◽  
John L. Jørgensen

AbstractWe have developed an optical stimulator system for vision-based sensors. The stimulator is an efficient tool for stimulating a camera during on-ground testing with scenes representative of spacecraft flights. Such scenes include starry sky, planetary objects, and other spacecraft. The optical stimulator is used as a test bench to simulate high-precision navigation by different types of camera systems that are used onboard spacecraft, planetary rovers, and for spacecraft rendezvous and proximity maneuvers. Careful hardware design and preoperational calibration of the stimulator result in high precision and long-term stability. The system can be continuously used over several days. By facilitating a full camera including optics in the loop, the stimulator enables the more realistic simulation of flight maneuvers based on navigation cameras than pure computer simulations or camera stimulations without the involvement of the actual optics.

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1076 ◽  
Author(s):  
Louzguine-Luzgin ◽  
Jiang

Thermal stability of different types of metallic glasses and partially crystalline alloys stored for at least 15 years at ambient conditions was tested in the present work by differential scanning calorimetry in comparison with that of the original alloys tested in the as-cast state in the earlier works. The structure of the naturally aged alloys was also studied by X-ray diffractometry. The structure of a couple of selected alloys was also tested by transmission electron microscopy. Most of the alloys retained their initial structure and showed only a moderate decrease in the crystallization temperature. Only those alloys which showed visible surface oxidation (Cu-Zr-system based) were partly transformed into a crystalline state forming micron-scale Cu particles in air at ambient conditions.


1990 ◽  
Vol 01 (02n03) ◽  
pp. 233-258 ◽  
Author(s):  
ROCH BOURBONNAIS ◽  
ROGER MAYNARD

We present extensive results of computer simulations on vibrations in one- and two-dimensional lattices with quartic anharmonicity. The existence of localized mode in ordered lattice is confirmed but the long term stability is questionable. Rather our results indicate an ergodic behavior at large times when several modes are present. Concerning disordered systems we have found that anharmonicity leads to a surprising new phenomenon of anomalous diffusion and thus to the possibility of anharmonically induced transport.


2009 ◽  
Vol 103 (2) ◽  
pp. 305-322 ◽  
Author(s):  
Kirill Rachinskiy ◽  
Hergen Schultze ◽  
Matthias Boy ◽  
Uwe Bornscheuer ◽  
Jochen Büchs

Author(s):  
Bjørnar Karlsen ◽  
Kåre Lind ◽  
Helge Malmbekk ◽  
Per Ohlckers

A high-precision voltage buffer and a 10:1 resistive voltage divider have been constructed for use in ac voltage and electrical power metrology. Long-term stability of the buffer's dc response has been demonstrated by two dc sweeps performed 20 days apart, with best-fit linearized gain varying less than 1 μV/V. The absolute ac gain has been measured using a high-precision digital multimeter for 10 Hz and 1 kHz with results consistent with dc within 5 μV/V. This value agrees with the characterization of ac–dc difference using thermal converters from different producers with a variety of resistance for various voltages from 1 V to 5 V. The ac–dc difference was further characterized better than 40 μV/V for the same voltages up to 100 kHz and better than 100 μV/V for 3 V at 1 MHz. Absolute ac gain and ac–dc difference has also been measured for the voltage divider and buffer combination from 10 V to 50 V, with similar agreement up to 1 kHz. The ac–dc difference from 10 Hz to 100 kHz of this combination shows an agreement well within 30 μV/V in this entire voltage span with a total response not exceeding 125 μV/V. This make the voltage divider and buffer combination suitable for sampling electrical powers for a wide range of voltages.


2020 ◽  
Vol 20 ◽  
Author(s):  
Taha Umair Wani ◽  
Roohi Mohi-ud-din ◽  
Reyaz Hassan Mir ◽  
Asif Mohd Itoo ◽  
Khalid Bashir Mir ◽  
...  

: Exosomes are nano structured (50-90 nm) vesicles that originate from endosomal compartment of eukaryotic cells and are secreted into extracellular matrix. In recent years there has been increased interest in exploring exosomes for diagnostic and therapeutic applications. Like many other diseases e.g. neurodegenerative disorders, autoimmune diseases exosomes have large significance in cancer too. Exosomes are known to prevail in large numbers and carry unique cargos in different types of cancers and thus are proving as versatile entities in understanding their biology of cancers and utilized as efficient diagnostic biomarkers in identification of cancer type. In addition to diagnostic applications there has been an increased interest in recent years to exploit exosomes as carriers for delivery of therapeutic agents to target sites as well. This is indebted to their exceptional non-immunogenic and biomimetic properties that prompted researchers to use exosomes as carriers for delivery of therapeutic agents e.g. drugs, genes and peptides. Exosomes also circumvent many drawbacks associated with other lipid or polymeric nanocarriers e.g. low circulation time, lipid toxicities, long term stability etc. However, in spite of many favorable aspects for exosome based therapy there have been a number of challenges too. This review will focus on the current status of the exosome based drug therapy for cancer, the challenges faced and its potential for future clinical use.


Shinku ◽  
2002 ◽  
Vol 45 (6) ◽  
pp. 519-524 ◽  
Author(s):  
Akihiko YONENAGA ◽  
Katsuhisa SAITOU ◽  
Tokihiko KOBATA ◽  
Masahiro HIRATA ◽  
Akira OOIWA

2010 ◽  
Vol 24 (4) ◽  
pp. 249-252 ◽  
Author(s):  
Márk Molnár ◽  
Roland Boha ◽  
Balázs Czigler ◽  
Zsófia Anna Gaál

This review surveys relevant and recent data of the pertinent literature regarding the acute effect of alcohol on various kinds of memory processes with special emphasis on working memory. The characteristics of different types of long-term memory (LTM) and short-term memory (STM) processes are summarized with an attempt to relate these to various structures in the brain. LTM is typically impaired by chronic alcohol intake but according to some data a single dose of ethanol may have long lasting effects if administered at a critically important age. The most commonly seen deleterious acute effect of alcohol to STM appears following large doses of ethanol in conditions of “binge drinking” causing the “blackout” phenomenon. However, with the application of various techniques and well-structured behavioral paradigms it is possible to detect, albeit occasionally, subtle changes of cognitive processes even as a result of a low dose of alcohol. These data may be important for the consideration of legal consequences of low-dose ethanol intake in conditions such as driving, etc.


2005 ◽  
Vol 26 (2) ◽  
pp. 100-106 ◽  
Author(s):  
James D.A. Parker ◽  
Donald H. Saklofske ◽  
Laura M. Wood ◽  
Jennifer M. Eastabrook ◽  
Robyn N. Taylor

Abstract. The concept of emotional intelligence (EI) has attracted growing interest from researchers working in various fields. The present study examined the long-term stability (32 months) of EI-related abilities over the course of a major life transition (the transition from high school to university). During the first week of full-time study, a large group of undergraduates completed the EQ-i:Short; 32 months later a random subset of these students (N = 238), who had started their postsecondary education within 24 months of graduating from high school, completed the measures for a second time. The study found EI scores to be relatively stable over the 32-month time period. EI scores were also found to be significantly higher at Time 2; the overall pattern of change in EI-levels was more than can be attributed to the increased age of the participants.


Sign in / Sign up

Export Citation Format

Share Document