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Wei Liu, Xing Dai, Yanlong Wang, Liping Song, Lin-Juan Zhang, Duo Zhang, Jian Xie, Long Chen, Juan Diwu, Jianqiang Wang, Zhi-Fang Chai, Shuao Wang
Traditional analytical methods of thorium contamination suffer from several disadvantages such as time-consuming procedure and equipment-intensive nature, leading to substantial challenges in rapid and onsite monitoring of thorium concentration in complex natural water systems. We report here the first case of luminescent metal organic framework based probe (ThP-1) for highly sensitive and selective self-calibrated sensing of Th4+ contamination in natural fresh water media with a notably facilitated detection procedure...
December 5, 2018: Environmental Science & Technology
Caifeng Ding, Yunxia Li, Lei Wang, Xiliang Luo
A sensitive and reliable bimodal electrochemiluminescent (ECL) system based on CdTe Quantum Dots (QDs) and luminol as double luminophores is constructed. CdTe QDs tagged with the aptamer (CdTe-Apt 2) of cancer cells are used as the detection signal, while luminol molecules are used as internal standards. The electrodeposited polyaniline based conducting polymer hydrogel (CPH) on the electrode surfaces improves the biocompatibility and conductivity of the sensing interfaces effectively. Furtherly, electron transfer is probably much easier when luminol and coreactant potassium persulfate (K2S2O8) immobilized in the CPH compared to that in solution...
November 30, 2018: Analytical Chemistry
Xueping Ju, Changxiang Yan, Junqiang Zhang, Bin Yang, Wenhe Xing
Retardation errors of high-order retarders will decrease the accuracy of a channeled spectropolarimeter. Taniguchi et al. have proposed a self-calibration method to calibrate the retardations [Opt. Lett.31, 3279 (2006)OPLEDP0146-959210.1364/OL.31.003279]; however, they do not take into account the inevitable alignment errors of high-order retarders. In this paper, an adaptive correction method with immunity to alignment errors is proposed to reduce the effects of temperature variation on retardations. By separating and analyzing the amplitude terms and phase terms contained in the measurement data, the phase terms are utilized to correct the retardations, which makes the effectiveness of this adaptive correction method immune to the inevitable alignment errors of high-order retarders...
October 1, 2018: Applied Optics
Stanislas Rapacchi, Thomas Troalen, Zakarya Bentatou, Morgane Quemeneur, Maxime Guye, Monique Bernard, Alexis Jacquier, Frank Kober
PURPOSE: To accelerate cardiac cine at 7 tesla using simultaneous multi-slice (SMS) acquisition with self-calibration to resolve misalignment between calibration and imaging data due to breathing motion. METHODS: A spoiled-gradient echo cine sequence was modified with radiofrequency phase-cycled SMS excitations. A Fourier encoding strategy was applied along the cardiac phase dimension to allow for slice untangling and split-slice GRAPPA calibration. Split-slice GRAPPA was coupled with regular GRAPPA (SMS-GRAPPA) and L1-SPIRiT (SMS-L1SPIRiT) for image reconstruction...
November 19, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Peng Sun, Nai-Guang Lu, Ming-Li Dong, Bi-Xi Yan, Jun Wang
Highly accurate and easy-to-operate calibration (to determine the interior and distortion parameters) and orientation (to determine the exterior parameters) methods for cameras in large volume is a very important topic for expanding the application scope of 3D vision and photogrammetry techniques. This paper proposes a method for simultaneously calibrating, orienting and assessing multi-camera 3D measurement systems in large measurement volume scenarios. The primary idea is building 3D point and length arrays by moving a scale bar in the measurement volume and then conducting a self-calibrating bundle adjustment that involves all the image points and lengths of both cameras...
November 15, 2018: Sensors
Minruihong Wang, Huiliang Cao, Chong Shen, Jin Chai
This paper proposes an effective method to calibrate the microelectromechanical systems (MEMS) vibratory gyroscope based on the virtual Coriolis force. This method utilizes a series of voltage signals to simulate the Coriolis force input, and the gyroscope output is monitored to obtain the scale factor characteristics of the gyroscopes. The scale factor and bias parameters of the gyroscope can be calibrated conveniently and efficiently in the sense-mode open loop. The calibration error of the scale factor based on the turntable and the virtual Coriolis force method is only 1...
June 28, 2018: Micromachines
Yue Wang, Xiangjun Wang, Zijing Wan, Jiahao Zhang
Nowadays, binocular stereo vision (BSV) is extensively used in real-time 3D reconstruction, which requires cameras to quickly implement self-calibration. At present, the camera parameters are typically estimated through iterative optimization. The calibration accuracy is high, but the process is time consuming. Hence, a system of BSV with rotating and non-zooming cameras is established in this study, in which the cameras can rotate horizontally and vertically. The cameras' intrinsic parameters and initial position are estimated in advance by using Zhang's calibration method...
October 29, 2018: Sensors
T Thiele, Y Lin, M O Brown, C A Regal
Atomic magnetometry is one of the most sensitive ways to measure magnetic fields. We present a method for converting a naturally scalar atomic magnetometer into a vector magnetometer by exploiting the polarization dependence of hyperfine transitions in rubidium atoms. First, we fully determine the polarization ellipse of an applied microwave field using a self-calibrating method, i.e., a method in which the light-atom interaction provides everything required to know the field in an orthogonal laboratory frame...
October 12, 2018: Physical Review Letters
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 the capacity of cellular antioxidants and ultimately trigger cell apoptosis in tumor biology. However, the roles of hypochlorite (ClO- ) in this process are much less clear compared with those of 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 NP) composed of two kinds of phosphorescent iridium(III) complexes (Ir1 and Ir2) encapsulated with amphiphilic DSPE-mPEG5000...
October 24, 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 21, 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
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