نتایج جستجو برای: polymethl methacrylate pmma
تعداد نتایج: 12631 فیلتر نتایج به سال:
We have systematically measured the differential stress-optic coefficient, DeltaC, in a number of poly(methyl methacrylate) (PMMA) fibers drawn with different stress, ranging from 2 up to 27 MPa. DeltaC was determined in transverse illumination by measuring the dependence of birefringence on additional axial stress applied to the fiber. Our results show that DeltaC in PMMA fibers has a negative...
In a prospective controlled trial 290 consecutive patients were randomly allocated a polymacon or a poly(methyl methacrylate) (PMMA) intraocular lens. Early Treatment of Diabetic Retinopathy Study (ETDRS) acuity charts gave similar results with both lenses. However Pelli-Robson contrast sensitivity charts gave a better result with PMMA lenses. Polymacon lenses appeared to remain free of any adh...
This study proposes a thermostable refractive index (RI) sensor consisting of a silica microsphere coated with a poly(methyl methacrylate) (PMMA) layer. The first-order and second-order whispering gallery modes (WGMs) of both TE and TM polarizations are considered theoretically. The layer thickness is carefully optimized to eliminate the thermal drift and enhance the RI sensitivity and detectio...
We report diffuse reflection imaging in air of concealed powdered samples using a terahertz quantum cascade laser. The sensitivity of the detection scheme to sub-surface absorption within samples is confirmed using fully-characterized powdered admixtures of polystyrene and polymethyl methacrylate (PMMA). Measurements of the backscattering intensity from these samples are then used in conjunctio...
A linear accelerator based source of coherent radiation, FLASH (Free-electron LASer in Hamburg) provides ultra-intense femtosecond radiation pulses at wavelengths from the extreme ultraviolet (XUV; lambda<100nm) to the soft X-ray (SXR; lambda<30nm) spectral regions. 25-fs pulses of 32-nm FLASH radiation were used to determine the ablation parameters of PMMA - poly (methyl methacrylate). Under t...
This work shows the improvements in the sensing capabilities and precision of an Optical Microbubble Resonator due to the introduction of an encaging poly(methyl methacrylate) (PMMA) box. A frequency fluctuation parameter σ was defined as a score of resonance stability and was evaluated in the presence and absence of the encaging system and in the case of air- or water-filling of the cavity. Fu...
Poly Methyl MethAcrylate (PMMA) based plastic optical fibres offer a low cost radiation monitoring solution with a wide dose range, capable of providing real-time, online information. The sensitivity of the fibre to ionising radiation is shown to be dependant on wavelength, with the sensitivity increasing with decreasing wavelength, and so by carefully selecting the monitoring wavelength, the d...
The most common bone cement material used clinically today for orthopedic surgery is poly(methyl methacrylate) (PMMA). Conventional PMMA bone cement has several mechanical, thermal, and biological disadvantages. To overcome these problems, researchers have investigated combinations of PMMA bone cement and several bioactive particles (micrometers to nanometers in size), such as magnesium oxide, ...
On the basis of lithium electrolyte mechanism, modified glassy polymers were developed by adding salts to poly(methyl methacrylate) (PMMA). This review summarizes how rheological and mechanical properties PMMA changed introducing various salts: perchlorate (LiClO4), trifluoroacetate (LiCOOCF3), trifluoromethanesulfonate (LiCF3SO3), nonafluorobutanesulfonate (LiC4F9SO3), bromide (LiBr). It was f...
In this work, blends of polyethylene glycol (PEG) and poly(methyl methacrylate) (PMMA) with nanosponge-like porous structure are fabricated by a solution phase separation method, subsequently the nanosponge-porous also applied for high performance triboelectric nanogenerator (TENG). The features controlled varying polymer concentrations PEG/PMMA ratios. A TENG device made PEG-PMMA blend convex-...
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