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Laboratory and clinical reliability of two spectrophotometers
摘要： Objective: To evaluate the repeatability, interexaminer, and interdevice reliability of two clinically applicable spectrophotometers under laboratory and clinical conditions. Material and Methods: For the in vitro part of the study, measurements were performed by the use of Vita Easyshade Advance 4.0 (ES-A) and the Easyshade V (ES-V) at identical positions on different shade tabs (3D-Master; Vita Zahnfabrik, Bad S?ckingen, Germany). To test repeatability, one shade tab was measured 50 times by one operator. To determine interrater and interdevice agreement, two operators used both devices to perform 10 measurements on five different shade tabs. Clinical interdevice and interexaminer reliability was checked with a positioning jig used (15 participants). Measurement accuracy of both devices was evaluated for the recommended color of shade tabs. Results: Repeatability of results from both Easyshades was excellent for all color components (maximum deviation between measurements was ≤0.1 units). Interrater agreement was also perfect (intraclass correlation, ICC = 1.000). Interdevice agreement was lower, but still good (ICC ≥ 0.834). In the clinical environment, interrater and interdevice agreements were similar (ICC > 0.964 and ICC > 0.873). Accuracy was satisfactory for both devices, with both observers in full agreement for nearly 80% of ratings. Conclusions: Both Easyshades produced reliable and accurate measurements and can therefore be recommended for clinical determination of tooth color. Clinical Significance: The outcome of this study might help clinicians estimate the performance of a new digital shade determination device.
关键词： L*a*b*,accuracy,reliability,Easyshade,spectrophotometer
更新于2025-09-23 15:23:52
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[IEEE 2018 VII. Lighting Conference of the Visegrad Countries (Lumen V4) - Trebic, Czech Republic (2018.9.18-2018.9.20)] 2018 VII. Lighting Conference of the Visegrad Countries (Lumen V4) - Analysis of Liquid Dielectrics by Photometric Instruments
摘要： The liquid dielectrics are used as an electrical insulation or as a medium for heat transfer in the power energy and high voltage devices such as transformers, HV cables or bushings. However dielectric degradations of these liquids are formed in time, most often caused by chemical pollution, thermal destruction or by the electric field influences. Especially electric strength and dissipation factor of insulating oil are affected by these negative influences. The result is the deterioration of devices isolation, which may cause the termination of devices life or even fire or explosion. To avoid loss of the device and further damage, the oil is periodically sampled from the device. The sample of oil is then analyzed, diagnosed and measured in the laboratory. Electrical parameters, mechanical and optical properties are the most common measured quantities. The optical analysis is usually very fast and reliable. There are many commercial analysis devices available on the market. However, none of them can measure all the parameters according to the standards with user settings. The design and realization of optical diagnostic equipment for analysis of liquid dielectrics according ISO 2049 and EN 60422 are the main contribution of this paper. Next monitored parameter is the spectral absorption and transparency of these liquids in the visible and UV spectrum. The proper function and accuracy of the measured methods will be verified in the Light laboratory and in the CVVOZEPower Laboratory in Brno University of Technology.
关键词： spectroradiometer,D-lamp,insulating oil,silicone oil,UV-vis,mineral oil,spectrophotometer,liquid dielectric,spectroscopy,spectrum
更新于2025-09-23 15:21:21
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Cuvette-based microfluidic device integrated with nanostructures for measuring dual Localized Surface Plasmon Resonance (LSPR) signals
摘要： A spectrophotometer that uses a localized surface plasmon resonance phenomenon is a powerful measurement tool in the biotechnology and bioanalysis fields. We propose a novel cuvette design type that can be used for universal spectrophotometers. The novel cuvette design needs a few μl reagent for measuring, and also two chips for measurement can be loaded and measured at the same time. A new cuvette can easily be used several times because of sample chips to be loaded and unloaded since they are mechanically mounted by screws. Therefore, it can offer advantages to users in terms of cost and time. We verify its possibility for use in the biotechnology and bioanalysis fields by a signal enhancement and dual signal detection.
关键词： spectrophotometer,bioanalysis,nanostructures,microfluidic device,biotechnology,Localized Surface Plasmon Resonance,LSPR
更新于2025-09-23 15:21:01
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Relative analysis of the dependency of spectrophotometric data on temperature using textiles, ceramics, plastics, paints, and printed materials
摘要： It is generally known that the color of an object changes with the change of its surface temperature. The purpose of this study is to investigate the relative dependency of measured colorimetric data on the temperature variation of an object for different types of colored materials. Specifically, textile fabrics, ceramic tiles, plastic plaques, ink-printed paper cards, and paint-coated cards were utilized, and the results were evaluated. The impacts of temperature alteration on the CIELAB colorimetric data were examined and evaluated. The total color difference and differences in the CIE coordinates of each colored sample, compared with the measured color data at 20°C, are presented. The results reveal how each measured CIE colorimetric coordinate, as well as color difference, varies with the surface temperature of the object for samples of different types of colored materials.
关键词： color difference,temperature,color measurement,spectrophotometer
更新于2025-09-23 15:19:57
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Spectrophotometric color evaluation of permanent incisors, canines and molars. A cross-sectional clinical study
摘要： Background and aims. An accurate color reproduction represents the final validation level of an esthetic anterior or posterior restoration. The aim of this study was to evaluate the color of permanent maxillary incisors, canines and molars, using a clinical spectrophotometer. Methods. The Vita Easyshade Advance 4.0? intraoral spectrophotometer was used by one clinician to determine the color of 369 permanent maxillary incisors, canines and molars. The best matches to Vitapan Classical? and 3D-Master? shade guides were recorded. A one-way analysis of variance and Kruskal-Wallis test were used to compare L*, a*, b*, c* and h* color coordinates among the 3 types of teeth. Differences between the mean values of all color coordinates were evaluated by use of Bonferroni corrections. Color difference (ΔE*) between incisors, canines and molars was calculated from ΔL*, Δa* and Δb* data and the results were compared to ΔE*=3.3 acceptability threshold. Results. Except for Δa* and Δh* between canines and molars, statistically significant differences among the mean differences of all color coordinates were found when the 3 types of teeth were compared by pairs. The most frequently measured shades were A1 (48.4%), respectively 1M1 (31.5%) for incisors, B3 (36.6%), respectively 2M3 (39.8%) for canines and B3 (44.7%), respectively 2M3 (52%) for molars. Incisors had the highest lightness values, followed by canines and molars. Molars were the most chromatic with the highest a* and b* values. Conclusions. Despite the limitations of this study, color differences among incisors, canines and molars were found to be statistically significant, above the clinical acceptability threshold established. In conclusion, successful esthetic restorations of permanent teeth of the same patient need an individual color assessment and reproduction of every type of tooth.
关键词： spectrophotometer,permanent natural teeth,color
更新于2025-09-19 17:15:36
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Broadband dependence of atmospheric transmissions in the UV and total solar radiation
摘要： Atmospheric broadband transmissions of clouds, aerosols, and ozone in the erythemally weighted ultraviolet (EUV, 290–320 nm), total (spectrally integrated) ultraviolet (TUV, 290–363 nm), and total global solar (GS, 305–2800 nm) spectral regions were analysed with ground-based measurements in Seoul, Korea (37.57°N, 128.98°E) from March 2004 to February 2013. The annual average total transmission expressed as a fraction of the clear-sky irradiance was 77.6% in the EUV, 73.6% in the TUV, and 72.0% in the GS spectral regions. The corresponding values for cloud transmission were 78.4%, 73.9%, and 71.7%. In overcast cloudy conditions, atmospheric transmission was reduced by 45.9%, 50.2%, and 56.6% in the three spectral regions, respectively, indicating the dominant effect of clouds. Aerosol and ozone transmissions had almost the same annual average. Annual average atmospheric transmission effectively decreases with increasing wavelength from EUV to GS regions. However, we found that there was a difference in wavelength dependence of atmospheric transmission for monthly averages, which seems related to the monthly variation of total column ozone (TCO), aerosol, and cloud amount. It is also found that there is a critical value of TCO (TCO =370 DU) for the wavelength dependence of transmission. Higher ozone amount than this turnaround value can cause an increase in transmission from the EUV to GS regions. The monthly wavelength-dependent effects may be attributable more to the different climatological characteristics of the TCO rather than aerosols and clouds.
关键词： modification factor,Brewer spectrophotometer,ultraviolet,surface solar irradiance,transmission
更新于2025-09-19 17:15:36
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Comparison of accuracies of an intraoral spectrophotometer and conventional visual method for shade matching using two shade guide systems
摘要： Background and Objectives: This in vitro study compared the shade matching abilities of an intraoral spectrophotometer and the conventional visual method using two shade guides. The results of previous investigations between color perceived by human observers and color assessed by instruments have been inconclusive. The objectives were to determine accuracies and interrater agreement of both methods and effectiveness of two shade guides with either method. Methods: In the visual method, 10 examiners with normal color vision matched target control shade tabs taken from the two shade guides (VITAPAN Classical? and VITAPAN 3D Master?) with other full sets of the respective shade guides. Each tab was matched 3 times to determine repeatability of visual examiners. The spectrophotometric shade matching was performed by two independent examiners using an intraoral spectrophotometer (VITA Easyshade?) with five repetitions for each tab. Results: Results revealed that visual method had greater accuracy than the spectrophotometer. The spectrophotometer; however, exhibited significantly better interrater agreement as compared to the visual method. While VITAPAN Classical shade guide was more accurate with the spectrophotometer, VITAPAN 3D Master shade guide proved better with visual method. Conclusion: This in vitro study clearly delineates the advantages and limitations of both methods. There were significant differences between the methods with the visual method producing more accurate results than the spectrophotometric method. The spectrophotometer showed far better interrater agreement scores irrespective of the shade guide used. Even though visual shade matching is subjective, it is not inferior and should not be underrated. Judicious combination of both techniques is imperative to attain a successful and esthetic outcome.
关键词： spectrophotometer,shade guide,Accuracy,dental shade matching,repeatability
更新于2025-09-19 17:15:36
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - The Possibilities of Using LED Photometry and Ellipsometry Technology for Monitoring the Aquatic Anvironment
摘要： This paper develops new information-instrumental tools for operative diagnostics of the water objects including a detection of negative processes in their functioning. These tools are based on the big data approach and use such instrumental means as multi-channel optical sensors using of which provides the e?ciency and reliability of the diagnostics results. The system consists of a LED spectrophotometer and a LED spectroellipsometer, an information interface, a set of algorithms for identifying spectral images, a database of spectral standards, algorithms for solving inverse problems of spectrophotometry, spectroellipsometry, and an algorithm for learning the recognition of spectral images. Information-modeling instrumental technology developed in this paper has adaptation function to the spatial water objects and provides their water quality diagnostics on the base of episodic in-situ measurements.
关键词： spectroellipsometer,spectrophotometer,ellipsometry,LED photometry,aquatic environment monitoring
更新于2025-09-19 17:13:59
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Synthesis of ZnO nanoparticles in polyvinyl alcohol solutions using laser assisted synthesis in solution (LASiS) method
摘要： ZnO nanoparticles are widely studied because of their superior properties so they are widely used in various applications. Structural modification with the right synthesis method is the key to getting superior properties. In this experiment, Laser Assisted Synthesis in Solution (LASiS) method was used to synthesize ZnO nanoparticles. The LASIS method was carried out using a metal plate Zn as a target placed in a solution of polyvinyl alcohol (PVA) with different concentrations, namely 1%, 2%, 3% and 4%. This laser ablation has caused a solution of gray colloidal ZnO nanoparticles. Different PVA concentrations do not affect the color of the produced ZnO nanoparticle solution. The properties and structure of ZnO nanoparticles were characterized using UV-Vis spectrophotometer, Zetasizer spectrometer, and Transmission Electron Microscopy (TEM). The UV visible absorbance spectrum shows the maximum absorption characteristics of ZnO nanoparticles observed at a wavelength of 344 nm. The maximum absorbance value rises by increasing the concentration of PVA and reaching the maximum value at a concentration of 3%. These ZnO nanoparticles have a size around 80 nm. TEM analysis shows that ZnO nanoparticles have a spherical shape and have good crystallinity based on SAED measurements. This property is due to the role of PVA in the synthesis process.
关键词： ZnO nanoparticles,polyvinyl alcohol,UV-Vis spectrophotometer,Zetasizer spectrometer,LASiS method,Transmission Electron Microscopy
更新于2025-09-12 10:27:22
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Low-frequency Raman spectrophotometer with wide laser illumination on the sample: A tool for pharmaceutical analytical analysis
摘要： This work describes an optical configuration for a Raman spectrophotometer, which permits variation of the laser spot size from 3 to 3000 μm, maintaining a high Raman photons throughput and allowing acquisitions with a short integration time. In addition, the instrument can acquire spectra from the low to middle frequency vibrational range (10 to 2000 cm-1), on the Stokes and anti-Stokes sides. One of the features of this new optical configuration is the non-use of beam splitters to redirect the scattered light to the detector, which would sacrifice the laser power. The quantitative and qualitative analytical performances of the Raman spectrophotometer were evaluated using chemometric models to predict the concentrations of different active pharmaceutical ingredients (APIs) in mixtures with polymorphs and excipients, as well as by analysis of an API mixture employing hyperspectral imaging. This new optical configuration was shown to be versatile for pharmaceutical purposes and could be used in applications such as the characterization of new drugs or the quality control of raw materials and processes, using normal Raman measurements or SERS (surface-enhanced Raman scattering).
关键词： Raman spectrophotometer,instrumentation,wide area illumination,low-frequency,paracetamol
更新于2025-09-11 14:15:04