STUDY ON GYMNASTICS RING MOVEMENTS USING FORCE MEASURING SYSTEM

The purpose of this paper was to analyze five giant-swing phases performed on the rings using force-measuring system, which was synchronized with EMG and film. The results showed similar patterns in pulling force, shoulder angle, hip angle, hip velocity and ankle velocity when performing the movements of backward swing phase, dropped shoulder, giant-swing, and upward swing phase. The pulling-force changed from smaller than the body weight to greater than the body weight in the process of the backward swing. The first peak of pulling force occurred as shoulder drop phase ends. The second peak of pulling force occurred in the backward swing phase. The pulling force decreased gradually in the process of the upward swing

Dilution-induced current-density increase in disordered organic semiconductor devices:A kinetic Monte Carlo study

Using three-dimensional kinetic Monte Carlo simulations, we systematically investigate the effect of dilution with an inert material on the current density in unipolar sandwich-type disordered organic semiconductor devices. Such a dilution technique was studied experimentally by Abbaszadeh et al. [Nat. Mater. 15, 628 (2016)], who observed a dilution-induced increase of the current density. The authors explained the effect as a result of a reduced density of trapped charges ("trap dilution"), assuming an exponential density of trap states. Our simulations support this explanation, and show under which conditions this trap-dilution-induced increase of the current density becomes more than outweighed by the negative effect of the dilution-induced decrease of the mobility. The effect is studied for sets of systematically varied material parameters, including systems with a Gaussian shape of the host and trap DOS.</p

Image-Force-Stabilized Interfacial Dipole Layer Impedes Charge Injection into Disordered Organic Semiconductors

We show using three-dimensional kinetic Monte Carlo simulations that the injection of charge carriers from a metallic electrode into a disordered organic semiconductor is under nominally Ohmic injection conditions strongly impeded by the short-range Coulomb interactions between the charge carriers in the image-force-stabilized interfacial dipole layer. In contrast, master equation and conventional one-dimensional drift-diffusion simulations underestimate these Coulomb interactions due to their mean-field approximation, and are found not to reveal the effect. The simulations predict a reduction of the current density in organic semiconductor devices when the nominal injection barrier is taken very small or even negative, consistent with recent experimental results [Kotadiya et al., Nat. Mater. 17, 329 (2018)]. However, whereas in that work a modification of the energetic disorder near the interface is assumed, we find that the effect is already obtained after including charge-charge interactions beyond a one-dimensional and mean-field approximation. </p

Humic acid production from the degradation of Yima coal by Cunninghamella elegans combined with Bacillus sp.

Biodegradation is one of the important ways for the clean and efficient utilization of coal. However, the effectiveness of degradation by the combination of fungi and bacteria has not been well understood. In the present study, the combined degradation of the Yima coal was tested. The coal samples were firstly oxidized with nitric acid, followed by cultured in the media of Cunninghamella elegans and Bacillus sp.. The absorbance of A450, pH and metallic element (Cr, As, Mn, Pb, Co, Ni, Cu, Zn, Mo) contents of the degradation solution were determined by UV-visible spectrophotometry, pH meter and inductively coupled plasma mass spectrometry, respectively. The humic acid was analyzed by element analyzer, Fourier transform infrared spectroscopy and gas chromatog-raphy-mass spectrometry. The results showed that the humic acid yields of C. elegans, Bacillus sp. and their mixture were 58.17%, 61.00% and 67.17%, respectively. The pH of the degradation solution of mixed strains was similar to that of the bacteria. The characteristic products of the bacteria degradation were detected in the humic acid samples derived from mixed strains, while the opposite was true for the fungi. It was suggested that the combination of the two strains enhanced the alkaline environment and improved the degradation rate of nitric acid-treated coal. The bacteria played a leading role in the degradation process. Metallic elements (Cr, As, Mn, Pb, Co, Ni, Cu, Zn, Mo) were transferred from coal to the degradation solution during the degradation process, and the contents of Cr, As, Pb, Ni, Cu and Mo were fitted with A450, the coefficient of determination (R2) were greater than 0.6. It indicated that the contents of these six metal elements in the degradation solution could represent the degradation rate. Chemically extracted humic acid and biologically extracted humic acid were rich in the active functional groups such as carboxyl, hydroxyl, carbonyl, long-chain fatty acids (C16, C18) and four pyrrole derivatives. The biologically extracted humic acid also contained fatty acids (C3, C4, C5, C13, C14, C15), of smaller molecular weight, as well as nitrogen-containing compounds such as two pyrrole derivatives and a furan. The contents of C and H elements in the biologically extracted humic acid were higher than that in the chemically extracted humic acid

A multi-species approach for protected areas ecological network construction based on landscape connectivity

The establishment of ecological networks is crucial for biodiversity conservation, especially at broad spatial scales. It is still challenging to develop an ecological network construction method based on landscape connectivity for multiple species. The purpose of this study is to propose a multi-species framework approach for constructing ecological networks and determine the restoration priority for four focal mammal species across the protected areas in the western mountains of Henan Province, China. We built ecological networks for each species by using circuit theory and least-cost path models, and integrated the ecological corridors and key barrier areas to determine the restoration priority for multiple species. The results showed that the connectivity of the ecological network was closely related to the species dispersal capacity. For species with higher dispersal capacity, all core areas were interconnected and have multiple alternative paths, and the network of protected areas seemed to be well connected. With the decline of species dispersal ability, ecological networks became more complex and not well connected, and more migration corridors that exceed species dispersal capability have emerged. It was important to consider the needs for species-specific management plans. Key ecological corridors and barrier areas, which have significant impacts on species migration, are mainly land use areas dominated by cropland. Our research indicates that the methods proposed in this study can help determine the restoration priority of key ecological corridors and barrier areas, which may facilitate conservation efforts for multiple species, especially in areas with poor species distribution and movement data

Intermodulation Linearity in High-k/Metal Gate 28 nm RF CMOS Transistors

This paper presents experimental characterization, simulation, and Volterra series based analysis of intermodulation linearity on a high-k/metal gate 28 nm RF CMOS technology. A figure-of-merit is proposed to account for both VGS and VDS nonlinearity, and extracted from frequency dependence of measured IIP3. Implications to biasing current and voltage optimization for linearity are discussed

Modeling and Mitigating LED Nonlinearity using Nonlinear ARX model with Wavelet Networks

In this paper, a nonlinear autoregressive exogenous (NARX) model with a wavelet network is applied to model and compensate the nonlinearity of the LED in Visible Light Communications (VLC). The NARX model shows the ability to accurately describe the response of the LED. PAM-4 signal with a symbol rate of 5 Msym/s is used to demonstrate the performance of the NARX adaptive compensator. The eyediagrams show that this compensator can substantially improve the distorted signal. The complexity of the NARX adaptive compensator is relatively low, with only 15 units. This also facilitates the adaptive parameters updating process due to the small number of parameters in the NARX adaptive compensator

LED Nonlinearity Post-compensator with Legendre polynomials in Visible Light Communications

The nonlinear effect of Light-Emitting Diodes (LEDs) is one of the important factors that hamper the bit rate of Visible Light Communications (VLC). To mitigate the nonlinearity, we propose a Legendre-polynomials-based post-compensator derived from a post-distorter deduced by a physical-based nonlinear LED model. We represent the formulation of the post-distorter with Legendre series expansion to ease the computation burden for training coefficients. Since only feed-forward structure is embodied in the series representation, the coefficients of the proposed compensator are easy to access with adaptive algorithms of low complexity. To validate the effectiveness of our proposed model, we adopt Recursive Least Square (RLS) and Least Mean Square (LMS) algorithms to train the coefficients of our proposed compensator with the same iteration steps. In particular, RLS achieves lower Mean square Errors (MSEs) with faster convergence speed. Due to the relatively low complexity of these nonlinear algorithms, our proposed compensator is more actual for implementation on VLC hardware platforms like Field-Programmable Gate Array (FPGA)

Self-Healing Flexible Conductive Film by Repairing Defects via Flowable Liquid Metal Droplets

Self-healing flexible conductive films have been fabricated, evaluated, and applied. The film is composed of a fragile indium tin oxide (ITO) layer covered with sprayed liquid metal (LM) droplets. Self-healing of electrical conductivity is achieved via spontaneous capillary wicking of LM droplets into cracks/defects of the ITO film. The liquid metal adhering onto the ITO layer can also connect the ITO fragments during bending to keep the overall conductivity of the composite LM/ITO film stable. Stable and reversible electrowetting performance has been achieved with the composite LM/ITO as the conductive film, in either flat or curved states

Achievable Rate of MIMO-OFDM VLC over Low-Pass Channels

Visible light communication (VLC) is a short-range optical wireless communication (OWC) utilizing white light-emitting diode (LED) lighting, so that the VLC systems can provide both illumination and communication. Multiple-input multiple-output (MIMO) is an attractive technology to efficiently improve the achievable rate of VLC with multiple LED luminaries which experience a low-pass effect in practical channels. In this paper, we investigate the performance of MIMO-VLC over three general low-pass channels, including exponential, first-order and Gaussian low-pass channels. Over frequency domain, two power loading strategies for multi-subcarrier orthogonal frequency division multiplexing (OFDM) are considered, namely uniform power loading and water-filling power loading. Expressions on the achievable rate to the corresponding link power budget and bandwidth are derived. Low-pass MIMO-OFDM VLC with a matrix channel decomposition has not extensively been treated theoretically in literature, to the best of our knowledge