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Georgette M Lang, Dirk Skaper, Frank Hampel, John A Gladysz
Three routes are explored to the title halide/cyanide complexes trans-Fe(CO)(NO)(X)(P((CH2)14)3P) (9c-X; X = Cl/Br/I/CN), the Fe(CO)(NO)(X) moieties of which can rotate within the diphosphine cages (ΔH(‡)/ΔS(‡) (kcal mol(-1)/eu(-1)) 5.9/-20.4 and 7.4/-23.9 for 9c-Cl and 9c-I from variable temperature (13)C NMR spectra). First, reactions of the known cationic complex trans-[Fe(CO)2(NO)(P((CH2)14)3P)](+) BF4(-) and Bu4N(+) X(-) give 9c-Cl/-Br/-I/-CN (75-83%). Second, reactions of the acyclic complexes trans-Fe(CO)(NO)(X)(P((CH2)mCH[double bond, length as m-dash]CH2)3)2 and Grubbs' catalyst afford the tris(cycloalkenes) trans-Fe(CO)(NO)(X)(P((CH2)mCH[double bond, length as m-dash]CH(CH2)m)3P) (m/X = 6/Cl,Br,I,CN, 7/Cl,Br, 8/Cl,Br) as mixtures of Z/E isomers (24-41%)...
October 18, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Matthew J Murray, Hannah M Ogden, Carlos Toro, Qingnan Liu, Amy S Mullin
We report state-resolved collision dynamics for CO molecules prepared in an optical centrifuge and measured with high resolution transient IR absorption spectroscopy.Time-resolved polarization-sensitive measurements of excited CO molecules in the J=29 rotational state reveal that oriented angular momentum of CO rotors is relaxed by impulsive collisions.Translational energy gains for molecules in the initial plane of rotation are 3-fold larger than for randomized angular momentum orientations, indicating the presence of anisotropic kinetic energy...
October 6, 2016: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Shailesh Srivastava, Shreesha Rao D S, Hari Nandakumar
We report the first proof-of-principle demonstration of the resonant optical gyroscope with reflector that we have recently proposed. The device is very different from traditional optical gyroscopes since it uses the inherent coupling between the clockwise and counterclockwise propagating waves to sense the rotation. Our demonstration confirms our theoretical analysis and simulations. We also demonstrate a novel method of biasing the gyroscope using orthogonal polarization states. The simplicity of the structure and the readout method, the theoretically predicted high sensitivities (better than 0...
October 3, 2016: Scientific Reports
Li He, Huan Li, Mo Li
Photons carry linear momentum and spin angular momentum when circularly or elliptically polarized. During light-matter interaction, transfer of linear momentum leads to optical forces, whereas transfer of angular momentum induces optical torque. Optical forces including radiation pressure and gradient forces have long been used in optical tweezers and laser cooling. In nanophotonic devices, optical forces can be significantly enhanced, leading to unprecedented optomechanical effects in both classical and quantum regimes...
September 2016: Science Advances
Changlong Li, Shiqiao Gao, Shaohua Niu, Haipeng Liu
This paper presents analytical models, as well as numerical and experimental verification of intrinsic dissipation due to thermoelastic loss in tuning-fork resonator. The thermoelastic analytical governing equations are created for resonator vibrating at drive-mode and sense-mode, and thermoelastic vibration field quantities are deduced. Moreover, the theoretical values are verified that coincided well with finite element analysis (FEM) simulation results. Also, the comparison of vibration field quantities is made to investigate the effect of different conditions on resonator thermoelastic vibration behavior...
2016: Sensors
Zhi-An Deng, Guofeng Wang, Danyang Qin, Zhenyu Na, Yang Cui, Juan Chen
To exploit the complementary strengths of WiFi positioning, pedestrian dead reckoning (PDR), and landmarks, we propose a novel fusion approach based on an extended Kalman filter (EKF). For WiFi positioning, unlike previous fusion approaches setting measurement noise parameters empirically, we deploy a kernel density estimation-based model to adaptively measure the related measurement noise statistics. Furthermore, a trusted area of WiFi positioning defined by fusion results of previous step and WiFi signal outlier detection are exploited to reduce computational cost and improve WiFi positioning accuracy...
2016: Sensors
Alexis Nez, Laetitia Fradet, Pierre Laguillaumie, Tony Monnet, Patrick Lacouture
In the fields of medicine and biomechanics, MEMS accelerometers are increasingly used to perform activity recognition by directly measuring acceleration; to calculate speed and position by numerical integration of the signal; or to estimate the orientation of body parts in combination with gyroscopes. For some of these applications, a highly accurate estimation of the acceleration is required. Many authors suggest improving result accuracy by updating sensor calibration parameters. Yet navigating the vast array of published calibration methods can be confusing...
August 30, 2016: Medical Engineering & Physics
Zhang Luo, Chaojun Liu, Shuai Yu, Shengzhi Zhang, Sheng Liu
A new virtual gyroscope with multi-gyroscope and accelerometer array (MGAA) is proposed in this article for improving the performance of angular rate measurement. Outputs of the virtual gyroscope are obtained by merging the signals from gyroscopes and accelerometers through a novel Kalman filter, which intentionally takes the consideration of the MEMS gyroscope error model and kinematics theory of rigid body. A typical configuration of the virtual gyroscope, consisting of four accelerometers and three gyroscopes mounted on designated positions, is initiated to verify the feasibility of the virtual gyroscope with MGAA...
August 2016: Review of Scientific Instruments
Hansong Guo, He Huang, Liusheng Huang, Yu-E Sun
As the size of smartphone touchscreens has become larger and larger in recent years, operability with a single hand is getting worse, especially for female users. We envision that user experience can be significantly improved if smartphones are able to recognize the current operating hand, detect the hand-changing process and then adjust the user interfaces subsequently. In this paper, we proposed, implemented and evaluated two novel systems. The first one leverages the user-generated touchscreen traces to recognize the current operating hand, and the second one utilizes the accelerometer and gyroscope data of all kinds of activities in the user's daily life to detect the hand-changing process...
2016: Sensors
Shih-Hau Fang, Hao-Hsiang Liao, Yu-Xiang Fei, Kai-Hsiang Chen, Jen-Wei Huang, Yu-Ding Lu, Yu Tsao
This paper investigates the transportation and vehicular modes classification by using big data from smartphone sensors. The three types of sensors used in this paper include the accelerometer, magnetometer, and gyroscope. This study proposes improved features and uses three machine learning algorithms including decision trees, K-nearest neighbor, and support vector machine to classify the user's transportation and vehicular modes. In the experiments, we discussed and compared the performance from different perspectives including the accuracy for both modes, the executive time, and the model size...
2016: Sensors
Gertrúd Tamás, Andrea Kelemen, Péter Radics, István Valálik, Dustin Heldman, Péter Klivényi, László Vécsei, Eszter Hidasi, László Halász, Dávid Kis, Péter Barsi, Péter Golopencza, Loránd Erőss
INTRODUCTION: A different innervation pattern of proximal and distal muscles from the contra- and ipsilateral motor circuits raises the question as to whether bilateral, contra- and ipsilateral subthalamic stimulation may have different effects on the distal and proximal movements of the upper limb. To answer this question, we performed kinematic analyzes in patients with Parkinson's disease. METHODS: Twenty-eight Parkinsonian patients treated by bilateral subthalamic stimulation were examined with an age-matched control group of 28 healthy subjects...
October 1, 2016: Brain Research
Wei Wang, Xiyuan Chen
Modeling and compensation of temperature drift is an important method for improving the precision of fiber-optic gyroscopes (FOGs). In this paper, a new method of modeling and compensation for FOGs based on improved particle swarm optimization (PSO) and support vector machine (SVM) algorithms is proposed. The convergence speed and reliability of PSO are improved by introducing a dynamic inertia factor. The regression accuracy of SVM is improved by introducing a combined kernel function with four parameters and piecewise regression with fixed steps...
August 10, 2016: Applied Optics
Vassilis Gikas, Harris Perakis
With the rapid growth in smartphone technologies and improvement in their navigation sensors, an increasing amount of location information is now available, opening the road to the provision of new Intelligent Transportation System (ITS) services. Current smartphone devices embody miniaturized Global Navigation Satellite System (GNSS), Inertial Measurement Unit (IMU) and other sensors capable of providing user position, velocity and attitude. However, it is hard to characterize their actual positioning and navigation performance capabilities due to the disparate sensor and software technologies adopted among manufacturers and the high influence of environmental conditions, and therefore, a unified certification process is missing...
2016: Sensors
Lyndia C Wu, Kaveh Laksari, Calvin Kuo, Jason F Luck, Svein Kleiven, Cameron R 'Dale' Bass, David B Camarillo
Wearable inertial sensors measure human head impact kinematics important to the on-going development and validation of head injury criteria. However, sensor specifications have not been scientifically justified in the context of the anticipated field impact dynamics. The objective of our study is to determine the minimum bandwidth and sample rate required to capture the impact frequency response relevant to injury. We used high-bandwidth head impact data as ground-truth measurements, and investigated the attenuation of various injury criteria at lower bandwidths...
September 6, 2016: Journal of Biomechanics
Ahmet Turan Özdemir
Wearable devices for fall detection have received attention in academia and industry, because falls are very dangerous, especially for elderly people, and if immediate aid is not provided, it may result in death. However, some predictive devices are not easily worn by elderly people. In this work, a huge dataset, including 2520 tests, is employed to determine the best sensor placement location on the body and to reduce the number of sensor nodes for device ergonomics. During the tests, the volunteer's movements are recorded with six groups of sensors each with a triaxial (accelerometer, gyroscope and magnetometer) sensor, which is placed tightly on different parts of the body with special straps: head, chest, waist, right-wrist, right-thigh and right-ankle...
2016: Sensors
R P van der Logt, O Findling, H Rust, O Yaldizli, J H J Allum
BACKGROUND: Patients with multiple sclerosis (MS) suffer from diminished balance control due to slowed sensory conduction and possibly delayed central processing. Vibrotactile biofeedback of trunk sway has been shown to improve balance control in patients with peripheral and central vestibular disorders. Here, the effects of vibrotactile feedback training on trunk sway and a possible carry-over effect was measured in MS patients during stance and gait. METHODS: Ten MS patients (mean age 46...
July 2016: Multiple Sclerosis and related Disorders
Yanwei Guan, Shiqiao Gao, Haipeng Liu, Lei Jin, Yaping Zhang
In this paper, a stiffness match method is proposed to reduce the vibration sensitivity of micromachined tuning fork gyroscopes. Taking advantage of the coordinate transformation method, a theoretical model is established to analyze the anti-phase vibration output caused by the stiffness mismatch due to the fabrication imperfections. The analytical solutions demonstrate that the stiffness mismatch is proportional to the output induced by the external linear vibration from the sense direction in the anti-phase mode frequency...
2016: Sensors
Zhongxing Gao, Yonggang Zhang, Yunhao Zhang
Improving the performance of interferometric fiber optic gyroscope (IFOG) in harsh environment, especially in vibrational environment, is necessary for its practical applications. This paper presents a mathematical model for IFOG to theoretically compute the short-term rate errors caused by mechanical vibration. The computational procedures are mainly based on the strain distribution of quadrupolar fiber coil measured by stress analyzer. The definition of asymmetry of strain distribution (ASD) is given in the paper to evaluate the winding quality of the coil...
2016: Sensors
Jin Sun, Xiaosu Xu, Yiting Liu, Tao Zhang, Yao Li
In order to reduce the influence of fiber optic gyroscope (FOG) random drift error on inertial navigation systems, an improved auto regressive (AR) model is put forward in this paper. First, based on real-time observations at each restart of the gyroscope, the model of FOG random drift can be established online. In the improved AR model, the FOG measured signal is employed instead of the zero mean signals. Then, the modified Sage-Husa adaptive Kalman filter (SHAKF) is introduced, which can directly carry out real-time filtering on the FOG signals...
2016: Sensors
Alexander A Krylov, Dmitriy S Chernykh, Natalia R Arutyunyan, Vyacheslav V Grebenyukov, Anatoly S Pozharov, Elena D Obraztsova
We report on the stable picosecond and femtosecond pulse generation from the bidirectional erbium-doped all-fiber ring laser hybridly mode-locked with a coaction of a single-walled carbon nanotube-based saturable absorber and nonlinear polarization evolution that was introduced through the insertion of the short-segment polarizing fiber. Depending on the total intracavity dispersion value, the laser emits conservative solitons, transform-limited Gaussian pulses, or highly chirped stretched pulses with almost 20 nm wide parabolic spectrum in both clockwise (CW) and counterclockwise (CCW) directions of the ring...
May 20, 2016: Applied Optics
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