Fabrication commercial testing and adjustment equipment of optical instruments
Sign In View Cart 0 Help. Share Email Print. Volume Details. Volume Number: Date Published: 29 October Table of Contents. Cryogenic optical and mechanical test result of a 1.VIDEO ON THE TOPIC: OPTICAL INSTRUMENTS -- in HINDI
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Sign In View Cart 0 Help. Share Email Print. Volume Details. Volume Number: Date Published: 29 October Table of Contents. Cryogenic optical and mechanical test result of a 1. Harris designed and manufactured a 1. This mirror assembly was examined using X-rays computer tomography for cross sectional views to detect any manufacturing defects.
The mirror assembly was tested for thermal stability at room temperature down to degrees Kelvin, followed with modal test in order to correlate to FEM models. Brent Knight ; H. The Advanced Mirror Technology Development AMTD project is in Phase 2 of a multiyear effort initiated in Fiscal Year to mature toward the next technology readiness level critical technologies required to enable 4-m-or-larger monolithic or segmented ultraviolet, optical, and infrared UVOIR space telescope primarymirror assemblies for general astrophysics and ultra-high-contrast observations of exoplanets.
The test article and support structure were suspended via bungee to simulate a free-free environment. Modes were excited by roaming an instrumented modal test hammer and responses were measured.
Predicted and measured frequencies are presented as well as Modal Assurance Criteria MAC results to compare the mode shapes. The finite element mirror model used for pre-test predictions and posttest comparisons was provided by the mirror vendor, Harris Corporation. The mirror FEM included deformations of the ribs that were a result of the slumping process.
Evaluation of changes in physical properties of low thermal expansion ceramics and glass induced by radiation Author s : Haruka Ueno; Tomohiro Kamiya ; Tadahito Mizutani Show Abstract. Cordierite ceramics have excellent physical properties such as a high elastic modulus, low bulk density, high thermal conductivity and low coefficient of thermal expansion CTE.
These features make cordierite ceramics attractive materials for ultra-lightweight and thermally-stable components used in changing thermal environments. Thus, cordierite ceramics have been widely used in ground-based precision systems, but have not yet been applied to space missions. Their resistance against the space environment must first be demonstrated in order to apply these materials to space missions. One of the main issues in the space environment is the deterioration of materials induced by space radiation.
The electrons and protons trapped around Earth and having energies of several MeV to tens of MeV cause ionization inside materials. Long-term radiation exposure may induce changes in physical properties, leading to degraded performance. This study evaluated two cordierite ceramics and a SiAlON ceramic for the changes in key physical properties i. The irradiation test conditions of 10 MeV energy and 2. The total fluence was irradiated in several divided doses, and the changes in physical properties were evaluated relative to increases in irradiation dose.
This result indicates that the cordierite ceramics have superior radiation resistance in terms of the stability of physical properties as compared to the low CTE glass materials. Study on polishing characteristics of cordierite ceramics for ultra-lightweight and thermally stable mirror applications Author s : Tomohiro Kamiya ; Tadahito Mizutani Show Abstract. Cordierite ceramics have excellent physical properties such as high elastic modulus, low bulk density, low coefficient of thermal expansion CTE and excellent long-term stability.
Due to these excellent features, cordierite ceramics have been widely used as highly stable structural components in precision metrology fields or semiconductor manufacturing systems. And given their excellent radiation resistance and pore-less surface that can be mirror-finished, cordierite ceramics should also be excellent as optical materials for ultra-lightweight and thermally stable space optics.
However, such an application as optical material requires not only superior material physical properties but also excellent machinability for optical polishing. In light of the few examples of applying cordierite ceramics to optical mirrors, there are few reports on the polishing characteristics of cordierite ceramics. Therefore, this study examined the polishing characteristics of cordierite ceramics in order to clarify the polishing conditions suitable for cordierite ceramics used for space optical applications.
The polishing processes were evaluated in terms of removal rate, figure accuracy and surface roughness by changing the polishing parameters. Preparation of yttria-dtabilized nanocrystalline zirconia with tunable optical properties Author s : G.
Uahengo; Y. Kodera; J. Garay Show Abstract. We present a systematic study investigating yttria dopant concentrations effects on crystal phase compositions of zirconium dioxide ZrO 2 and the respective bulk optical properties. ZrO2 , a traditional structural ceramic possesses excellent mechanical properties, while simultaneously possessing a wide band gap eV. This combination of properties opens the door for designs and fabrication of transparent structural ceramics.
This affords the opportunity to investigate, the effects of yttria dopant concentration on the resultant microstructure grain size, phases and phase ratios. As a high refractive index material, silicon is widely used for infrared thin-film coatings. However, the absorption of silicon films is relatively high, especially in the near infrared region with wavelengths less than 1. In this paper, we investigated the effect of post-deposition annealing on the microstructure and optical properties of silicon films.
The films were characterized by X-ray diffraction XRD , Raman spectroscopy, electronic-spin resonance ESR , and optical transmittance measurement, respectively.
The optical constants of the films were obtained by the simulation of transmission spectra. It was found that all the silicon films maintained amorphous in microstructure, but, with the increase of temperature, the amorphous network order was improved on both short-range and medium-range scales.
Meanwhile, extinction coefficient also fell to the minimum, and then increased by rising the annealing temperature further. These results showed that post-deposition annealing could reduce optical absorption of silicon films remarkably in the near infrared region, so as to improve the optical performance of the silicon films.
The focal length of the optical system was mm for a x pixel detector. The spatial resolution of the optical system has been designed less than 0. We have measured the spatial resolution to verify the optical performance. Also, we have observed a 2- cycle target at 3 km distance when the visibility was 1. We have proved to be able to get the image of a target by using our optical system with a SWIR detector in 1. China has started to develop its geostationary meteorological satellites and associated ground application systems since the s.
In the past 20 years, 6 FY-2 satellites were launched and put into application. About 10 years ago, China had planned to develop a new generation geostationary satellite, and the first one, named FY-4A, was launched on December 11, The Advanced Radiation Imager, one of the observing instruments onboard FY-4A meteorological satellite, has 14 optical channels with the spectral range cover from 0.
Five kinds of optical coating components, including high reflectance mirrors, dichroic beam splitters, lens, optical windows and bandpass filters, are used to construct the complex optical system. Metal and dielectric thin film materials are selected to design and fabricate these optical coatings. The spectrum measurement, reliability tests and simulated space environment tests are carried out, respectively. The images received by ground station indicate that optical coatings are competent to the application of Advanced Radiation Imager.
New approach to optical assembly and cementing Author s : Robert E. Parks Show Abstract. A novel method of projecting a reference axis in space for use in optical assembly of centered elements such as assembly in a barrel or in cementing multi-element lenses is presented.
An axicon grating, a set of concentric, uniformly spaced circles, when illuminated with a point source of light creates a line of bright spots surrounded by concentric rings in both transmission through, and reflection from, the grating.
This axis is easily interrogated with an autostigmatic microscope to gauge the distance a center of curvature, or other lens conjugate, lies from the axis created by the grating. Optical devices are extremely important since they play a critical role in optical recording and display.
Single point diamond turning is one of the most common methods to create plastic optics. Diamond turning of plastics is influenced by a wide variety of factors such as the glass transition temperature of the polymer, other material properties and operator controlled cutting conditions. Since diamond is one of the hardest materials in nature and polymers are relatively soft, little tool wear is expected. But the optics industry claims that tool wear is a major problem.
In the experimental conditions used, PMMA was found to have better surface finish than PC when machined with a zero-rake angle diamond tool. Polycarbonate was found to wear the tool more than PMMA under similar cutting conditions. It was also found that Polycarbonate is more sensitive to chip management and chip geometry than PMMA.
Detailed effects of all machining parameters for the two materials were studied. Doetz ; O. Dambon; F. Klocke; C. Vogt ; R. Rascher ; O. Ductile mode grinding is a finishing process usually being applied to generate molds in brittle materials e. To that aim, ultra-precision machineries UPM are applied controlling depth of cut not to exceed a critical value, h cu,crit e. Recent process analyses of the ductile mode grinding process of brittle materials have demonstrated that the critical indentation depth h cu,crit , that determines the transition from brittle mode to ductile mode removal, can significantly be shifted to higher values by adjusting process parameters such as the type of coolant and its pH value: e.
This paper reports on a feasibility study to extend the process window of ductile mode material removal. Applying optimized ductile process parameter sets, enabling values of the critical depth of cut larger than 1 micron, single point diamond turning SPDT of binderless tungsten carbide molds has been successfully tested applying UPM machineries.
Experimental data will be presented demonstrating that by controlling and adjusting ductile process parameters only, it is possible to extend its process window into regimes that are today not yet machinable: binderless tungsten carbide molds for precision glass molding have been processed in a ductile removal mode by SPDT generating surface roughness levels of less than 2 nm rms.
An analysis of the adjustment of the critical process parameters will be presented together with a detailed description of the First Light experiments towards SPDT of binderless tungsten carbide molds. Ductile mode grinding is usually applied for finishing of e. Bifano et all. Furthermore, previous investigations have shown that hcu,crit strongly depends on coolant fluid characteristics as well as on the compressive stress applied into the cutting zone by the use of tools with e.
Following that trail, critical process parameters have been identified determining the process window of feed controlled ductile grinding applied on State-of-the-Art UPM machineries. The influences of the critical process parameters on the critical depth of cut hcu,crit have been tested experimentally using an ultra-precise SPDT machine.
Among others, four critical process parameters could be identified determining the transition between brittle and ductile mode grinding: the critical depth of cut depends substantially on a the type of coolant used, b the pH value of the coolant, c the tool tip radius of the applied diamond and d whether ultrasonic assistance US is being switched on or off.
That way, a new formula was developed, which allows the prediction of the critical depth of cut depending on critical process parameters, a. This formula was set up based on fundamental ruling test results and is one step towards extending Bifanos formula taking the influences of critical process parameters into account.
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Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. Since the early part of this century the manufacturing of optical components and systems has changed dramatically throughout the world, both in the types of products that are made and in the approach that is taken to making them. Once devoted entirely to passive image-forming components such as lenses and mirrors and to the instruments made from them, the industry now also manufactures a wide range of active elements such as lasers and optical sensors. Until recently, the industry depended heavily on a craftsman-style approach to manufacturing, with much of the work being carried out on an order-by-order basis by very small businesses.
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NDAKOTA - анаграмма. Она представила себе эти буквы и начала менять их местами. Ndakota… Kadotan… Oktadan… Tandoka… Сьюзан почувствовала, как ноги у нее подкосились. Стратмор прав.
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По-видимому, Танкадо считал, что два эти события чем-то различались между .
Двигаясь в дыму, она вдруг вспомнила слова Хейла: У этого лифта автономное электропитание, идущее из главного здания. Я видел схему. Она знала, что это .
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Что с тобой? - в голосе Стратмора слышалась мольба. Лужа крови под телом Хейла расползалась на ковре, напоминая пятно разлитой нефти.
Беккер взглянул на часы. Час сорок пять ночи. Он в недоумении посмотрел на двухцветного. - Ты сказал - в два ночи.
По выражению лица панка Беккер понял, что тот знает, о ком идет речь. Мелькнул лучик надежды. Но уже через минуту парень скривился в гримасе. Он с силой стукнул бутылкой по столу и вцепился в рубашку Беккера. - Она девушка Эдуардо, болван.
Я видел алгоритм. Уверяю вас, он стоит этих денег. Тут все без обмана. Он стоит десять раз по двадцать миллионов.