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Fangzheng Zhang, Jingzhan Shi, Yu Zhang, De Ben, Lijun Sun, Shilong Pan
Phase noise analyzers (PNAs) are indispensable for evaluating the short-term stability of microwave signals. In this Letter, a high-sensitivity PNA with self-calibration capability is proposed based on an optical frequency comb generator and an optical-hybrid-based I/Q detector. The negative factors that result in inaccurate measurement, including the direct component interference, amplitude noises of the microwave signal under test and the laser, and phase noise of the laser, are all eliminated through digital signal processing...
October 15, 2018: Optics Letters
William Salomon, Anne Dolbecq, Catherine Roch-Marchal, Grégoire Paille, Rémi Dessapt, Pierre Mialane, Hélène Serier-Brault
The luminescent [EuW10 O36 ]9- polyoxometalate has been introduced into the cavities of the highly porous zirconium luminescent metal-organic framework UiO-67 via a direct synthesis approach, affording the EuW10 @UiO-67 hybrid. Using a combination of techniques (TGA, BET, elemental analysis, EDX mapping,…) this new material has been fully characterized, evidencing that it contains only 0.25% in europium and that the polyoxometalate units are located inside the octahedral cavities and not at the surface of the UiO-67 crystallites...
2018: Frontiers in Chemistry
Martin Gaudreault, Ahmed Joubair, Ilian Bonev
This work shows the feasibility of calibrating an industrial robot arm through an automated procedure using a new, low-cost, wireless measuring device mounted on the robot's flange. The device consists of three digital indicators that are fixed orthogonally to each other on an aluminum support. Each indicator has a measuring accuracy of 3 µm. The measuring instrument uses a kinematic coupling platform which allows for the definition of an accurate and repeatable tool center point (TCP). The idea behind the calibration method is for the robot to bring automatically this TCP to three precisely-known positions (the centers of three precision balls fixed with respect to the robot's base) and with different orientations of the robot's end-effector...
October 10, 2018: Sensors
Yi Wang, Shaomin Lin, Jun Luo, Rui Huang, Hong Cai, Wei Yan, Huan Yang
Sesamol, is well-known antioxidant and can reduce the rate of oxidation and prolong expiration date. It is also potentially antimutagenic and antihepatotoxic, the detection of sesamol is important and remains a huge challenge. Herein, a new 3D alkaline earth Sr metal organic framework [Sr(BDC)DMACH₂O]n (BDC = benzene-1,4-dicarboxylate; DMAC = N , N -dimethylacetamide) is synthesized and a probe based on Tb3+ functionalized Sr-MOF. The Tb(3+)@Sr-MOF showed good luminescence and thermal property. Due to the energy competition between sesamol and ligand, the luminescence intensity of sesamol increases meantime luminescence intensity of Tb3+ decreases, the ratio of the emission intensities (I344 /I545 ) linearly increases with sesamol in concentrations ranging from 1 × 10-7 to 8 × 10-4 M...
October 7, 2018: Nanomaterials
T Yoshikawa, R Tsukizaki, H Kuninaka
This paper presents calibration devices and methods for the measurement of electric thruster performance parameters using a seesaw-type thrust stand to measure the mass loss of solid propellant in a vacuum. In previous studies, impact hammers and electrostatic combs have been manufactured for the calibration of the thrust and impulse using seesaw-type thrust stands. However, these conventional devices rely on self-calibration, which means that the input delivered by the device in unknown, and must undergo a calibration process themselves...
September 2018: Review of Scientific Instruments
Zi-Han Chen, Xin-Yue Han, Ling-Xue Deng, Zi-Yang Lin, Fang-Ya Mu, Shengqiang Zhang, Guoyue Shi, Min Zhang
Tb3+ -doped carbon dots (Tb3+ @CDs) were prepared in a facile hydrothermal method by using ammonium citrate as carbon source and Tb3+ as dopant. A 15-bp GT-rich single-strand DNA (ssDNA) was introduced to sensitize Tb3+ via the antenna effect for generating two fluorescence signals (CDs and Tb3+ ), forming a conjugate of Tb3+ @CDs/ssDNA. The ratiometric fluorescence of Tb3+ @CDs/ssDNA could be reversibly regulated by Ag+ and Cys, in which the fluorescence peak at 546 nm of Tb3+ could be switched to "On" or "Off" as the signal indicator while the fluorescence peak at 444 nm of CDs remained constant as the build-in reference...
January 1, 2019: Talanta
Xiangchun Meng, Yuxiang Shi, Zejing Chen, Linna Song, Menglong Zhao, Liang Zou, Shujuan Liu, Wei Huang, Qiang Zhao
Reactive oxygen species (ROS), when beyond the threshold, can exhaust capacity of cellular antioxidant and ultimately trigger cell apoptosis in tumor biology. However, the roles of hypochlorite (ClO-) in this process are much less clear compared with her ROS, and its detection is easily obstructed by tissue penetration and endogenous fluorophores. Herein, we first synthesized a near-infrared (NIR) ratiometric ClO- probe (Ir NPs) comprising two kinds of phosphorescent iridium(III) complexes (Ir1 and Ir2), encapsulated with amphiphilic DSPE-mPEG5000...
September 27, 2018: ACS Applied Materials & Interfaces
Md Sakibur Rahman Sajal, Md Kamrul Hasan
A novel method for highly accurate coil sensitivity-map estimation, based on a constrained image-domain multi-channel LMS (c-iMCLMS) algorithm, is proposed for image reconstruction using self-calibrating SENSE. The sensitivity information is extracted by developing an image-domain cross-relation equation using the low-resolution images constructed from the fully sampled central region of the variable density MR data. Then this formulation is solved in an iterative way using a novel sum-of-squares (SOS) constraint...
September 20, 2018: Magnetic Resonance Imaging
Idit Feder, Hamootal Duadi, Ruchira Chakraborty, Dror Fixler
An irradiated turbid medium scatters the light in accordance to its optical properties. Near-infrared (NIR) clinical methods, which are based on spectral-dependent absorption, suffer from an inherent error due to spectral-dependent scattering. We present here a unique spatial point, that is, iso-pathlength (IPL) point, on the surface of a tissue at which the intensity of re-emitted light remains constant. This scattering-indifferent point depends solely on the medium geometry. On the basis of this natural phenomenon, we suggest a novel optical method for self-calibrated clinical measurements...
March 31, 2018: ACS Omega
Zhang Jie, Yin Zenghe, Zhang Xiaolei, Zhu Yong
Quantitative surface-enhanced Raman scattering (SERS) in practical applications still remain unresolved, mainly due to low reproducibility relying on the quality of the SERS substrates. In this paper, a carbon nanotube and Ag nanoparticles composite (CNT/AgNPs) is reported, and the carbon nanotube is as an internal standard for the calibration of SERS intensity of analyte molecules. The quantification of analyte molecules rhodamine 6G (R6G) is demonstrated in an aqueous solution with the concentration of 10-9 to 10-7 M...
September 3, 2018: Optics Express
H W Si, B Wang, J W Dong, L J Wang
An accurate self-calibrated fiber transfer delay measurement method is demonstrated. Using the simplified self-calibration configuration, the measurement uncertainty of fiber transfer delay is improved. To demonstrate the accuracy of the method, the measurement results of two systems are compared. It shows that this method achieves a sub-picosecond accuracy. Besides, the chromatic dispersion of fiber under test is also obtained, which is in agreement with the nominal value.
August 2018: Review of Scientific Instruments
Jie Sui, Lei Wang, Tao Huang, Qi Zhou
The gyroscope, accelerometer and angular encoder are the most important components in a dual-axis rotation inertial navigation system (RINS). However, there are asynchronies among the sensors, which will thus lead to navigation errors. The impact of asynchrony between the gyroscope and angular encoder on the azimuth error and the impact of asynchrony between the gyroscope and accelerometer on the velocity error are analyzed in this paper. A self-calibration method based on navigation errors is proposed based on the analysis above...
September 3, 2018: Sensors
Yanying Wang, Lei Mao, Wei Liu, Fang Ding, Ping Zou, Xianxiang Wang, Qingbiao Zhao, Hanbing Rao
A turn-on fluorometric probe is described for the β-thalassemia drug deferiprone (DFP). The probe is making use of carbon dots (C-dots) and gold nanoclusters (AuNCs) which, under 340-nm excitation, display dual emission with peaks at 445 and 592 nm. The orange fluorescence of AuNCs is quenched after the addition of Fe(III), but recovered on addition of DFP. The blue fluorescence of the C-dots, in contrast, remains unchanged. The Fe(III)-DFP complex undergoes intermolecular electron transfer under UV excitation and displays only weak peaks in the UV region...
September 1, 2018: Mikrochimica Acta
Ying Zhou, Mrinmoy Maiti, Amit Sharma, Miae Won, Le Yu, Lan Xi Miao, Jinwoo Shin, Arup Podder, Kondapa Naidu Bobba, Jiyou Han, Sankarprasad Bhuniya, Jong Seung Kim
We report herein, an azo-derivative (AzP1) of FDA approved antineoplastic drug SN-38 (irinotecan analogue) as a theranostic agent with a potential for both tumor hypoxia-specific activation and therapy. The theranostic AzP1 was found to be stable within a biologically relevant pH scale and was chemically inert towards other competitive biological analytes. However, upon treatment with rat-liver microsomes, AzP1 showed a self-calibrated fluorescence enhancement at λem  = 560 nm. The cytotoxicity profile of AzP1 was tested in various cancer lines...
October 28, 2018: Journal of Controlled Release: Official Journal of the Controlled Release Society
Yilin Zhou, Ewelina Rupnik, Paul-Henri Faure, Marc Pierrot-Deseilligny
With the development of unmanned aerial vehicles (UAVs) and global navigation satellite system (GNSS), the accurate camera positions at exposure can be known and the GNSS-assisted bundle block adjustment (BBA) approach is possible for integrated sensor orientation (ISO). This study employed ISO approach for camera pose determination with the objective of investigating the impact of a good sensor pre-calibration on a poor acquisition geometry. Within the presented works, several flights were conducted on a dike by a small UAV embedded with a metric camera and a GNSS receiver...
August 24, 2018: Sensors
Jian Gao, Joseph Katz
This paper introduces the application of microscopic dual-view tomographic holography (M-DTH) to measure the 3D position and motion of micro-particles located in dense suspensions. Pairing of elongated traces of the same particle in the two inclined reconstructed fields requires precise matching of the entire sample volume that accounts for the inherent distortions in each view. It is achieved by an iterative volumetric self-calibration method, consisting of mapping one view onto the next, dividing the sample volume into slabs, and cross-correlating the two views...
June 25, 2018: Optics Express
Regina Eckert, Zachary F Phillips, Laura Waller
Fourier ptychography captures intensity images with varying source patterns (illumination angles) in order to computationally reconstruct large space-bandwidth-product images. Accurate knowledge of the illumination angles is necessary for good image quality; hence, calibration methods are crucial, despite often being impractical or slow. Here, we propose a fast, robust, and accurate self-calibration algorithm that uses only experimentally collected data and general knowledge of the illumination setup. First, our algorithm makes a fast direct estimate of the brightfield illumination angles based on image processing...
July 1, 2018: Applied Optics
Chien-Yuan Han, Cheng-You Du, De-Fu Chen
Starch is an essential and widely distributed natural material, but its detailed conformation and thermal transition properties are not yet well understood. We present a rapid Mueller matrix imaging system to explore the structural characteristics of starch granules by using 16 measurements with different incoming and outgoing polarizations. Due to the minimum rotation of the optical elements and the self-calibration ability of this system, the full Mueller matrix images can be accurately obtained within ten-odd seconds...
June 11, 2018: Optics Express
Yue Cheng, Huimin Zhang, Bin Yang, Jie Wu, Yixiao Wang, Bin Ding, Jianzhong Huo, Yan Li
The detection of phosphate (Pi) under physiological conditions is a very important issue in environmental and biological sciences. Herein, a unique fluorescent probe {[EuL(H2O)1.35(DMF)0.65]·1.9DMF}n (1) was prepared through the organic-inorganic hybridization between asymmetrical tricarboxylate ligands and Eu2O2 clusters under solvothermal conditions. The as-prepared sample 1 exhibited excellent fluorescence properties and could be designed as a self-calibrating fluorescent probe for sensitively and selectively detecting Pi which served as an essential substance in aquatic ecosystems and biological systems...
September 11, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Ahmed M M Almassri, Wan Zuha Wan Hasan, Siti Anom Ahmad, Suhaidi Shafie, Chikamune Wada, Keiichi Horio
This paper presents a novel approach to predicting self-calibration in a pressure sensor using a proposed Levenberg Marquardt Back Propagation Artificial Neural Network (LMBP-ANN) model. The self-calibration algorithm should be able to fix major problems in the pressure sensor such as hysteresis, variation in gain and lack of linearity with high accuracy. The traditional calibration process for this kind of sensor is a time-consuming task because it is usually done through manual and repetitive identification...
August 5, 2018: Sensors
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