摘要：
Gd3+-doped Bi4O5I2 with a flower-like structure has been successfully prepared for the first time using a one -step hydrothermal method. The effect of different doping amounts on the photodegradation properties has been investigated. The total removal of ciprofloxacin (CIP) by 3 % Gd-Bi4O5I2 (molar atomic ratio of Gd to Bi = 0.03:1) under visible light irradiation was 94.50 % (within 120 min). The reaction rate constant was 6.3 times higher than that of pure Bi4O5I2. In complex water containing humic acid (HA) and various anions, 3 % Gd-Bi4O5I2 maintained a high total removal rate for CIP. UV-Vis diffuse reflectance spectroscopy and electrochemical tests have shown that doping Gd3+ not only extends the photoresponse range, but also reduces the photonic band gap width. Gd3+ ions act as electron traps to trap excited electrons and promote the separation and migration efficiency of photogenerated electron-hole pairs, improving the performance of Gd-Bi4O5I2 composites for the photocatalytic degradation of CIP.
通讯机构：
[Wang, Z ] C;Changsha Univ Sci & Technol, Sch Elect & Informat Engn, State Key Lab Disaster Prevent & Reduct Power Grid, Changsha 410114, Peoples R China.
关键词：
Distribution networks;Electromagnetic potential transformer;Ferromagnetic resonance;Resonance suppression;Flexible grounding
摘要：
When a single line-to-ground (SLG) fault occurs in a distribution network, ferromagnetic resonance is easily triggered by magnetic saturation of the potential transformer (PT) after the fault disappears. To solve this problem, a method is proposed for ferromagnetic resonance suppression (FRS) in distribution networks based on flexible grounding technology. A controllable voltage is injected at the neutral point of the distribution network through a flexible grounding device (FGD) to suppress the neutral point voltage (NPV) of the system to zero, quickly restoring the system to the normal operating state, preventing magnetic saturation of the PT core, destroying the conditions for ferromagnetic resonance in the system, and realising FRS. The proposed method provides a release channel for the charge accumulated in the line-to-ground capacitance, consuming the electromagnetic energy stored in the circuit. Various resonant conditions are simulated in a PSIM 9.1 environment to verify the FRS process and effect of the proposed method. The simulation results show that the proposed method can quickly achieve FRS with a good detuning effect, simple control and a high response speed.
摘要：
Recently, single-layer PtSe(2), possessing high carrier mobility and optical response, has been successfully fabricated. To further expand its application scope and find new physics, in this work, we functionalized it via the adsorption of non-metallic atoms X (X = H, B, C, N, O, and F) to form hybrid systems X-PtSe(2), and their geometrical, mechanical, electronic, and optical properties as well as strain tuning effects were studied deeply. Calculations show that the energy stability of X-PtSe(2) systems is significantly enhanced, and they also hold higher thermal and mechanical stability. Particularly, X-PtSe(2) systems present excellent in-plane tenacity and out-of plane stiffness against deformations, which make them more applicable for designing nanodevices. Intrinsic PtSe(2) is a semiconductor, while the X-PtSe(2) system can be a band-gap narrowed semiconductor or metal, thus expanding the application scope for PtSe(2), and the odd-even effect of electronic phase variation related to the atomic number is found. Besides, the wavelength range of optical adsorption is increased in X-PtSe(2) systems, implying that its optical response region is wide, providing more options for developing optoelectronic devices. Moreover, it is shown that strain can flexibly tune the electronic property of X-PtSe(2) systems, especially enhancing the optical absorption ability substantially, beneficial for their applications in solar devices.
摘要：
For Mandelbrot's cascade (Y-n) in an independent and identically distributed (i.i.d.) random environment xi, we are interested in the a.s. convergence rate of the Mandelbrot's martingale (W-n) to its limit W, where W-n=Y-n/E xi Yn is the normalized partition function. We obtain sufficient conditions under which W-Wn has an exponential convergence rate: W-W-n=o(e(-na)) a.s. for some a > 0 explicitly calculated; we also find conditions under which W-Wn has a polynomial convergence rate: W-W-n=o(n(-alpha)) a.s. for some alpha > 0. Similar conclusions hold for Mandelbrot's cascade in a varying environment.
摘要：
Effects of steam explosion (SE) treatment (0.3-1.0 MPa, 30-90s) on the physicochemical and functional properties of dietary fiber (DF) extracted from tea residue were investigated. Results showed that SE led to the formation of porous and less compact microstructures of tea residues. Compared with the control sample (12.41 g/100 g), the content of soluble dietary fiber (SDF) was markedly increased by SE, reaching the maximum of 23.03 g/100 g when steam explored at 0.5 MPa for 90 s, due to the degradation of insoluble dietary fiber (IDF). The physicochemical and functional properties were significantly influenced by SE treatments. IDF exhibited decreased water holding capacity (WHC), swelling capacity (SC), oil holding capacity (OHC) after SE, whereas the physicochemical properties of SDF from SE-treated tea residues (0.3 MPa, 90s) were greatly improved. The glucose absorption capacity (GAC), cholesterol adsorption capacity (CAC), and nitrite ion adsorption capacity (NIAC) of both IDF and SDF showed trends of first increasing and then decreasing, indicating that excessive SE treatment resulted in poor properties of DF. These findings are of great value for the high-value utilization of agricultural by-product and development of functional foods.
作者机构：
[Deng, Zi-wei; Zhu, En-wen; Cao, Jun] Changsha Univ Sci & Technol, Dept Math & Stat, Changsha 410114, Peoples R China.;[Zhang, Han-jun] Xiangtan Univ, Sch Math & Computat Sci, Xiangtan 411105, Peoples R China.;[Liu, Xiao-hui] Jiangxi Univ Finance & Econ, Sch Stat & Data Sci, Nanchang 330013, Peoples R China.;[Liu, Xiao-hui] Jiangxi Univ Finance & Econ, Key Lab Data Sci Finance & Econ, Nanchang 330013, Peoples R China.
通讯机构：
[Zhu, EW ] C;Changsha Univ Sci & Technol, Dept Math & Stat, Changsha 410114, Peoples R China.
关键词：
random coefficient autoregressive model;time-functional variance;conditional least squares;semiparametric least squares
摘要：
This paper considers the random coefficient autoregressive model with time-functional variance noises, hereafter the RCA-TFV model. We first establish the consistency and asymptotic normality of the conditional least squares estimator for the constant coefficient. The semiparametric least squares estimator for the variance of the random coefficient and the nonparametric estimator for the variance function are constructed, and their asymptotic results are reported. A simulation study is presented along with an analysis of real data to assess the performance of our method in finite samples.
作者机构：
[Tang, Yu; Huang, Zhi-Yong; Wang, Wei; Huang, Ya-Lan; Liu, Qi; Zhang, Bing-Hao; Ren, Jin-Can; Wang, Xing-Yu; Chen, Bo-Wen] City Univ Hong Kong, Dept Phys, Hong Kong 999077, Peoples R China.;[Lan, Si; Liu, Qi; He, Zhang-Long; He, Hao] City Univ Hong Kong, Shenzhen Res Inst, Shenzhen 518057, Peoples R China.;[He, Hao; He, Zhang-Long] Changsha Univ Sci & Technol, Coll Mat Sci & Engn, Changsha 410114, Peoples R China.
通讯机构：
[Liu, Q ; Liu, Q; He, H ] C;City Univ Hong Kong, Dept Phys, Hong Kong 999077, Peoples R China.;City Univ Hong Kong, Shenzhen Res Inst, Shenzhen 518057, Peoples R China.
关键词：
Lithium-ion batteries;Ni fraction;Extreme fast charging;Structural evolution
摘要：
Lithium-ion batteries (LIBs) with extreme fast charging (XFC) capability are considered an effective way to alleviate range anxiety for electric vehicle (EV) buyers. Owing to the high ionic and electronic conductivity of LiNixCoyMnzO2 (x + y + z = 1, NCM) cathodes, the inevitable Li plating of graphite in NCM | graphite cell is usually identified as a key bottleneck for XFC LIBs. However, the capacity decay mechanism of cathode materials under XFC has not been fully investigated. In this work, three typical NCM cathode materials with different Ni fractions were chosen and their electrochemical performances under XFC associated with structural evolution were investigated. A faster capacity decay of NCMs under XFC conditions is observed, especially for Ni-rich NCMs. In-situ X-ray diffraction (XRD) reveals that the multiple c-axis parameters appear at the high-voltage regions in Ni-rich NCMs, which is probably triggered by the larger obstruction of Li (de)intercalation. Particularly, NCMs with moderate Ni fraction also present a similar trend under XFC conditions. This phenomenon is more detrimental to the structural and morphological stability, resulting in a faster capacity decay than that under low current charging. This work provides new insight into the degradation mechanism of NCMs under XFC conditions, which can promote the development of NCM cathode materials with XFC capability.
摘要：
安卓系统为浏览器分配资源时无法感知网页内容,会导致资源过度分配和电量不必要损失。同时,由于CPU可调节频率密度的增长,通过动态电压频率缩放(dynamic voltage and frequency scaling, D...展开更多 安卓系统为浏览器分配资源时无法感知网页内容,会导致资源过度分配和电量不必要损失。同时,由于CPU可调节频率密度的增长,通过动态电压频率缩放(dynamic voltage and frequency scaling, DVFS)技术实现能耗优化的难度也随之增大。另外在系统默认的调控策略下,忽视了图形处理器(graphics processing unit, GPU)对浏览器运行的作用。针对上述问题,提出一种协同调控CPU和GPU实现功耗优化的方法。首先根据网页加载时处理器运行特征利用逻辑回归对网页进行分类,对网页特征加权实现复杂度量化,根据类别与复杂度采用DVFS技术限制CPU频率的同时调节GPU频率。该方法被应用于谷歌Pixel2 XL上的Chromium浏览器,对排名前500的中文网站进行测试,平均节省了12%功耗的同时减少了5%网页加载时间。收起
摘要：
Internal erosion refers to the movement of fine particles within soil framework due to subsurface water seepage. Existing criteria for assessing internal erosion usually are based on static loading, and the effect of cyclic load is not considered. Additionally, there are limited studies to examine the particle -size distribution and origin of eroded fine particles. This study presents an experimental investigation that examines the impact of cyclic loading on internal stability through a series of seepage tests. The composition and origin of lost particles are quantitatively studied using particle staining and image recognition techniques. With increasing hydraulic gradient, particle erosion progresses from top layer to bottom layer, with a gradual increase in the maximum particle size of eroded particles from each layer. After significant loss of particles, the specimens reach a state of transient equilibrium, resulting in a gradual slowdown of both particle loss rate and average flow velocity. The results indicate that cyclic loading promotes massive particle loss and causes erosion failure of specimens that are considered stable according to existing criteria. The reason is that under cyclic loading, local hydraulic gradients is oscillating, and a larger than average hydraulic gradient may occur, which is responsible for the internal instability. The analysis suggests that existing criteria can provide a reasonable assessment of the relative stabilities of specimens under static loads but fail to capture the stabilities under cyclic loading conditions.
摘要：
The use of Glass Fiber Reinforced Plastics (GFRP) bars in coastal concrete structures can effectively prevent steel reinforcement corrosion, but research on the evolution of their performance in seawater and alkaline concrete environments is lacking. The analysis of the degradation process and mechanism of GFRP is thoroughly conducted in this paper through various characterization methods of morphology, mechanics, and material tests. Furthermore, the degradation law of GFRP in various erosion environments is assessed via multi-dimensional indexes. The findings indicate that the erosion of GFRP in an alkaline environment result in the debonding of resin and fiber, thereby causing the formation of cracks. As the erosion age and OH- concentration increase, the size of the cracks expands. Since the dissolution rate of the resin composed as part of GFRP is very low, the salt in seawater has minimal impact on the degradation of GFRP. Vickers hardness of the fiber with age decreased linearly and remained unchanged. Meanwhile, Vickers hardness of the resin with age can be divided into three stages: linear decline stage, linear rise stage, and stabilization stage. Under the erosive conditions, a hydrolysis reaction of the resin occurs resulting in the shortening of its molecular chain. The increase of alkalinity in GFRP attributed to the rising of O-H to C-H chemical bond ratio in the environment leads to the debonding of the fiber and resin. As a result, the resin flows out, and the hydrolysis rate slowly increased first, then accelerated, and finally stabilized.
摘要：
The challenge for practical application of frame structural optimization had previously been investigated by many works, while the mechanical performance requirements such as the displacement, stress, and stability requirements, were often considered separately within optimization, hindering their practical applications. For this purpose, an integrated topology and size optimization strategy of frame structures, in which the structural weight is taken as the objective with the constraints regarding the displacement, stress, as well as stability, is presented in this paper. Different from former researches, each beam is assigned with a topology variable representing the presence of the beam and a size variable correspond to the cross-sectional geometric properties. To achieve an optimized design with standard members, by cooperating the ordered multi-material SIMP (solid isotropic material with penalization) interpolation with the normalized Heaviside functions, the continuous size design variables are projected onto the discrete standard sizes conformed to standard library. Moreover, the comprehensive measure, including the stress relaxation, the pseudobuckling mode treatment scheme, the aggregation constraint, and varying constraint limit schemes, is employed to deal with the multiple constraints in the optimization model. Then, the sensitivities of the objective and constraint functions with respect to topology and size design variables are derived, respectively, and the proposed integrated optimization problem is solved by a nested optimization algorithm. Finally, several numerical examples are presented to demonstrate the feasibility of the proposed approach.
摘要：
Recycled rubber materials represent an environmentally sustainable option as asphalt modifiers. This research delves into the modification effects of Styrene Butadiene Rubber (SBR) asphalt at varying SBR content levels, employing a blend of molecular simulation techniques and laboratory experimentation. A comprehensive molecular model of SBR-modified asphalt is established, and molecular dynamics simulations are executed to scrutinize the thermodynamic attributes, dipole moments, mechanical characteristics, and adhesion properties inherent to SBR asphalt. The outcomes of this inquiry reveal that SBR exhibits notable compatibility with a majority of asphalt molecules, as evidenced by their dipole moments. The introduction of SBR into the asphalt matrix results in the adsorption of a substantial quantity of lightweight components, fostering the formation of a cross-linked network that bolsters the asphalt's resilience against external deformation forces. Furthermore, in terms of adhesion work, asphalt demonstrates heightened affinity with alkaline aggregates, and SBR serves to augment van der Waals interactions at the asphalt-aggregate interface, thereby amplifying interfacial bonding strength. However, when the content of SBR reaches 30%, some SBR molecules will be aggregated in the asphalt, which will lead to phase separation and affect the stability of the colloid. Therefore, it is recommended that the content of SBR should be limited to about 20% in practical engineering applications. In this work, the modification mechanism of SBR was analyzed at the molecular scale and verified experimentally, and the results provide a theoretical basis for the rational use of recycled SBR powder in asphalt applications.
通讯机构：
[Han, Y ] C;Changsha Univ Sci & Technol, Sch Civil Engn, 960 2nd Sect Wanjiali South Rd, Changsha 410114, Hunan, Peoples R China.
关键词：
3D nonlinear flutter analysis;Time-dependent nonlinear self-excited force model;Geometric nonlinearity;Long-span bridge;Full-mode nonlinear flutter analysis
摘要：
The present study aims to investigate the influence of geometric nonlinearity on post-flutter responses by developing a full-mode coupled nonlinear flutter analysis method (frequency-domain method) and a time-dependent nonlinear analysis scheme (time-domain method). This approach integrates the three-dimensional (3D) nonlinear finite element model and nonlinear self-excited force described by amplitude-dependent rational functions (RFs). By comparing post-flutter responses obtained from frequency-domain and time-domain methods, not only the influence of geometric nonlinearity on post-flutter responses is quantified, but also the underlying physical mechanism is revealed. The results show that the geometric nonlinear effect will become more significant with the increase of the amplitude and thus will induce a super-harmonic resonance behavior. The behavior is mainly characterized by the higher harmonic frequencies vibrations with higher-order mode shapes involved in the vertical and torsional displacement responses. Meanwhile, the larger the vibration amplitude, the more significant the super-harmonic resonance behavior. Besides, the geometric nonlinear effect will also cause a significant uplifting of the bridge deck in the vertical direction during 3D nonlinear flutter process. The main physical mechanism for the reduction in the amplitude of post-flutter response (dominated by the vibration with fundamental harmonic frequency) after considering the geometric nonlinear behavior is that the vibrations with higher harmonic frequencies play a role of absorbing energy and reducing vibration (similar to tuned mass damper effect) for the vibration with fundamental harmonic frequency. For the long-span suspension bridge with a main span of 1650 m studied in this study, the geometric nonlinear effect may need to be considered when the torsional amplitude at mid-span is only greater than 1.5 degrees.
摘要：
The accuracy of the data is crucial to the real-time prediction of autonomous driving. Due to factors such as weather and the accuracy of data collection equipment, there frequently exist noises in the data collected in real time. Therefore, it is necessary to perform analysis on acquired kinematic features related to driving behavior prediction. This study proposes a novel deep learning framework to explore influences of data noises on lane-changing intention prediction. Kinematic features including the longitudinal distance difference, velocity and acceleration, lateral velocity and acceleration of the vehicles are first extracted from the HighD. Then, the anti-interference performance of deep learning models such as transformer is tested. By comparing dataset with and without noises, we develop an evaluation method containing several predictive performance metrics and statistical measures. The results show that: (1) the longitudinal acceleration of the vehicle has the lowest sensitivity to noise, and the lateral velocity has the weakest anti-interference and the highest sensitivity. (2) The Bi-LSTM model with multi-head attention mechanism performs well in reducing the sensitivity of longitudinal acceleration and prediction accuracy. This study provides valuable information for data acquisition and model selection of real-time driving intention prediction.
