作者机构：
[Haishan Fan; Fan Gu; Junhui Zhang; Junhui Peng] School of Traffic and Transportation Engineering, Changsha University of Science & Technology, Changsha, Hunan, China;[Jianlong Zheng] National Engineering Research Center of Highway Maintenance Technology, Changsha University of Science & Technology, Changsha, Hunan, China
通讯机构：
[Fan Gu] S;School of Traffic and Transportation Engineering, Changsha University of Science & Technology, Changsha, Hunan, China
摘要：
This study aimed to develop a method to determine nonlinear viscoelastic properties of subgrade soil using the light weight deflectometer (LWD) test. Firstly, a constitutive model was developed to accurately characterize the nonlinear viscoelastic behavior of subgrade soil. A User-Defined Material Subroutine (UMAT) was coded to define this constitutive model in ABAQUS, which was verified by the virtual triaxial test analysis. Secondly, a numerical model was developed to simulate the LWD test, which considered the true LWD load pattern and the constitutive nature of subgrade soil. The sensitivity analysis demonstrated that the viscoelastic parameters significantly affected the deflection-time history curves. Subsequently, a batch calculation program was developed via MATLAB and ABAQUS to automatically compute the dynamic responses of subgrade in the LWD test. A total of 42,057 groups of subgrade deflection data were calculated under the LWD load, covering a wide range of nonlinear viscoelastic parameters. Finally, two machine-learning approaches (i.e., artificial neural network [ANN] and convolutional neural network [CNN]) were proposed to backcalculate these viscoelastic parameters of soil from the LWD load–deflection-time history data. The results showed that the CNN approach was much more accurate than the ANN approach for the backcalculation of the nonlinear viscoelastic properties of subgrade.
摘要：
Traditional amide-based hydrate inhibitors, vital for preventing blockages, face limitations due to increasingly stringent environmental regulations. This study focuses on modifying poly(N-vinylcaprolactam) (PVCap) to improve its inhibition and biodegradation properties, by introducing -OH, -NH2, or -COOH groups into the molecular structure. The results revealed that the -OH group significantly improved both hydrate inhibition and biodegradability, while the -COOH and - NH2 groups had moderate and counter-effects, respectively. Compared to end hydroxyl modification, multiple -OH groups in the vinylcaprolactam/vinylalcohol copolymer weaken the inhibition effect, despite enhancing biodegradability. Optimal hydrophilicity was found to enhance PVCap's KHI performance, emphasizing the delicate balance needed to optimize stability and effectiveness. PXRD, Raman spectroscopy and interfacial tension tests were used to elucidate the impact of the modified PVCaps on hydrate structure and gas-liquid interfacial properties. The results further highlighted the significance of appropriate amphiphilicity in augmenting the KHI effect of the modified PVCaps.
期刊：
Bulletin of Engineering Geology and the Environment,2024年83(1):1-13 ISSN：1435-9529
通讯作者：
Lan, T
作者机构：
[Gao, Q. F.; Zhang, R.] Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, 960 Wanjiali South Rd, Changsha 410114, Peoples R China.;[Lan, T.; Lan, T] Hunan Univ Sci & Technol, Sch Civil Engn, 2 Taoyuan Rd, Xiangtan 411201, Peoples R China.;[Zheng, J. L.] Changsha Univ Sci & Technol, Natl Engn Res Ctr Highway Maintenance Technol, 960 Wanjiali South Rd, Changsha 410114, Peoples R China.
通讯机构：
[Lan, T ] H;Hunan Univ Sci & Technol, Sch Civil Engn, 2 Taoyuan Rd, Xiangtan 411201, Peoples R China.
关键词：
Road engineering;Reinforced slope;Geogrid;Expansive soil;Field testing and monitoring
摘要：
The aim of this study is to better understand the long-term stability and reinforcement mechanism of expansive soil cut slopes repaired by geogrid reinforcement. A expansive soil slope repaired by geogrid was monitored for two years without interruption. The monitored results demonstrate that the water content of the reinforced expansive soil slope is gradually stabilized in two years after the treatment. The variation trend of geogrid strains is consistent with that of lateral earth pressures in the slope. The geogrid strain decreases with a decrease in earth pressure. When the earth pressure is stable, the geogrid strain approaches the initial value. The geogrid reinforcement is able to inhibit crack development, limit soil deformation and release soil swelling pressure, thus maintaining the long-term stability of expansive soil slope.
摘要：
A feasible route to fabricate phosphorus-doped carbon nanofibers (P-CNFs) with an inter-connected structure has been demonstrated through electrospinning, stabilization, and subsequent phosphoric acid impregnation and carbonization processes using polyacrylonitrile and lignin as carbon sources. The results illustrate that the phosphoric acid induced cross-linking could be beneficial to acquire the closed-pore structure and the heteroatom-doped surface chemistry of nanofibers. As a result, the P-CNFs exhibit higher interlayer spacing of graphite and lower BET specific surface area compared to the pristine CNFs. The P-CNFs as an anode material for sodium-ion batteries (SIBs) present a high reversible capacity 278 mA h g-1 at 0.2 A g-1 and a superior initial Coulomb efficiency (ICE) of 78.86 %. Moreover, the reversible capacity of P-CNFs can be stably maintained near the initial capacity after 5000 cycles at 1 A g-1, showing exceptional structural stability and cycling durability. Meanwhile, the sodium storage mechanism of P-CNFs was investigated using in-situ Raman and ex-situ XRD analysis to understand the exceptional structural stability and Na+ adsorption capacity of P-CNFs. This work provides valuable insights for the design of carbon nanofibers with an inter-connected structure as anode materials for SIBs, exhibiting outstanding electrochemical properties.
期刊：
Construction and Building Materials,2024年411:134518 ISSN：0950-0618
通讯作者：
Peng, H;Zhu, H
作者机构：
[Peng, Hui; Zhang, Bai] Changsha Univ Sci & Technol, Natl Key Lab Green & Long Life Rd Engn Extreme Env, Changsha 410114, Peoples R China.;[Zhang, Bai; Zhu, Hong; Zhu, H] Southeast Univ, Sch Civil Engn, Nanjing 211189, Peoples R China.;[Xu, Feng] China Construct Eighth Engn Div CORP LTD, Shanghai 200112, Peoples R China.
通讯机构：
[Peng, H ] C;[Zhu, H ] S;Changsha Univ Sci & Technol, Natl Key Lab Green & Long Life Rd Engn Extreme Env, Changsha 410114, Peoples R China.;Southeast Univ, Sch Civil Engn, Nanjing 211189, Peoples R China.
关键词：
Bond performance;Degradation mechanisms;Geopolymers;Coral aggregate concrete;BFRP bars;Seawater drying -wetting cycles
摘要：
The utilization of durable geopolymers instead of ordinary Portland cement (OPC) for developing geopolymerbased seawater coral aggregated concrete (GPCAC) in coastal constructions contributed to the improved marine resource utilization and the reduced CO2 emissions and construction costs. Thus, this study investigated the durability of GPCAC and its bond performance with basalt fiber-reinforced polymer (BFRP) bars under seawater drying-wetting cycles, and cement-based CAC was also selected as a comparison. The bond characteristics and degradation mechanisms of slag-based GPCAC and cement-based CAC specimens were compared and analyzed under different seawater exposure condition. Experimental results revealed that both GPCAC and CAC specimens demonstrated various degrees of degradation in bond strength, whereas their initial bond stiffness exhibited a slight increase owing to the hygroscopic expansion of the superficial epoxy resin of BFRP bars, after being exposed to seawater environmental attacks. This degraded bond strength was primarily attributed to the existence of corrosive ions (i.e., SO42-, Mg2+, and Cl-) in seawater and free OH- in concrete capillary pores. These compounds chemically reacted with the slurry hydration products and the resin matrix, which resulted in the decreasing of concrete strength, the hydrolysis of the resin matrix, the deterioration of fibers, and fiber-resin interface debonding. Compared with CAC specimens, GPCAC specimens achieved better resistance to seawater attacks owing to the more dense and stable reaction products formed by geopolymers compared to OPC. After being subjected to 60 degrees C seawater attacks for 12 months, approximately 4.9% and 12.0% reductions in the bond strength were reported for GPCAC and CAC specimens, respectively. Finally, the residual bond strength of both GPCAC and CAC specimens was predicted after being served in seawater erosion conditions for 50 years.
摘要：
Currently, the research on the mechanical properties of rubber-modified asphalt mixtures primarily focuses on small-scale investigations, with insufficient exploration into the performance of rubber particles and their relationship with the mechanism and properties of modified asphalt mixtures. Limited studies have been conducted on large-scale rubber modification in asphalt mixtures. Due to frequent use and subsequent high damage to existing asphalt pavements, incorporating rubber-modified asphalt mixtures can partially alleviate premature deterioration. Dynamic modulus tests were conducted using MTS equipment under unconfined conditions to investigate the viscoelastic behavior of rubber-modified asphalt mixtures with high rubber content and elucidate the influence of rubber particle content on the elastic deformation and recovery capability. The dynamic mechanical properties of the mixtures were determined at different loading rates, temperatures, and types of rubber-modified asphalt mixtures. Based on the test data, variations in the dynamic modulus, phase angle, storage modulus, loss modulus, loss factor, and rut factor of the rubber-modified asphalt mixtures under different loading frequencies, temperatures, and types were analyzed. The results demonstrate the pronounced viscoelastic behavior of rubber-modified asphalt mixtures. The mixtures exhibit enhanced elasticity at low temperatures and high frequencies, while their viscosity becomes more prominent at high temperatures and low frequencies. Under constant test temperatures, an increase in load loading frequency leads to a higher dynamic modulus; conversely, a decrease in dynamic modulus is observed with increasing test temperatures. The dynamic modulus of ARHM-25 at a frequency of 10 Hz is found to be 12.99 times higher at 15 degrees C compared to that at 60 degrees C, while at 30 degrees C, the dynamic modulus at 25 Hz is observed to be 2.72 times greater than that at 0.1 Hz. Furthermore, the rutting resistance factors of the asphalt mixtures increase with loading frequency but decrease with temperature. The rutting factor for ARHM-13 at a frequency of 10 Hz is found to be 22.98 times higher at 15 degrees C compared to that at 60 degrees C, while at a temperature of 30 degrees C, the rutting factor for this material is observed to be 3.09 times greater at a frequency of 25 Hz than at 0.1 Hz. These findings suggest that rutting is most likely when vehicles drive at low speeds in hot weather conditions.
摘要：
In order to improve the seismic performance of adjacent buildings, two types of tuned inerter damper (TID) damping systems for adjacent buildings are proposed, which are composed of springs, inerter devices and dampers in serial or in parallel. The dynamic equations of TID adjacent building damping systems were derived, and the H2 norm criterion was used to optimize and adjust them, so that the system had the optimum damping performance under white noise random excitation. Taking TID frequency ratio and damping ratio as optimization parameters, the optimum analytical solutions of the displacement frequency response of the undamped structure under white noise excitation were obtained. The results showed that compared with the classic TMD, TID could obtain a better damping effect in the adjacent buildings. Comparing the TIDs composed of serial or parallel, it was found that the parallel TIDs had more significant advantages in controlling the peak displacement frequency response, while the H2 norm of the displacement frequency response of the damping system under the coupling of serial TID was smaller. Taking the adjacent building composed of two ten-story frame structures as an example, the displacement and energy collection time history analysis of the adjacent building coupled with the optimum design parameter TIDs were carried out. It was found that TID had a better damping effect in the full-time range compared with the classic TMD. This paper also studied the potential power of TID in adjacent buildings, which can be converted into available power resources during earthquakes.
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：
Abstract: Aiming at the traditional A* algorithm which has the problems of traversing a large number of child nodes, the bottom of the search degree of freedom, and the path search efficiency caused by the large angle of the search direction, the research is carried out, and an improved A* algorithm is proposed. Firstly, in increasing the number of nodes and deleting the repetitive directions, a 16-neighborhood search method is formed, which enlarges the search angle. Then, the search interval is locally adjusted by using the direction information between the current node and the target point on the new neighborhood search method. The weight coefficients of the heuristic function and the evaluation function are improved to reasonably narrow the search neighborhood without the node falling into the local optimal solution. Finally, experiments are conducted in 16 simulated scenarios with different obstacle scales and different raster map sizes. The experimental results show that the improved A* algorithm significantly improves the search efficiency compared with the traditional algorithm, greatly reduces the number of searching sub-nodes, and improves the searching ability of the algorithm.#@#@#摘要: 针对传统的A*算法存在遍历子节点数量多、搜索自由度底、搜索方向夹角大所导致的路径搜索效率不高的问题进行了研究，提出一种改进的A*算法。首先增加节点数量，删除重复方向，建立16邻域搜索方式，扩大搜索角度。然后在新邻域搜索方式上，利用当前节点与目标点的方向信息局部调整搜索区间。改进启发函数和评价函数权重系数，在节点不陷入局部最优解的情况下，合理地缩小了搜索邻域。最后，在不同障碍物比例、不同栅格地图规模等16种模拟场景下进行实验。实验结果显示：改进A*算法相对于传统算法的搜索效率显著提高，极大地减少了搜索子节点的数量，提升了算法搜索的能力。
关键词：
integrated circuit;RTL code;code security;code obfuscation;XML syntax tree
摘要：
As the most widely used description code in digital circuits and system on chip (SoC), the security of register transfer level (RTL) code is extremely critical. Code obfuscation is a typical method to ensure the security of RTL code, but popular obfuscation methods are not fully applicable to RTL code. In addition, some RTL code obfuscation tools also have issues with incomplete functionality or obfuscation errors. In view of the above issues, this paper studies the RTL code security problem represented by obfuscation. Based on the extensible markup language (XML) syntax tree generated by parsing RTL code, a complete RTL code refactoring model is constructed, and four targeted RTL code obfuscation methods are proposed, namely: Layout obfuscation; Parameter obfuscation; Critical path obfuscation; Code increment obfuscation. Utilizing the developed obfuscation tool, an assessment of the performance and effectiveness of the obfuscation methods is conducted, alongside testing the equivalence between the obfuscated code and the source code. The experimental results show that the proposed obfuscation methods have higher practicability and reliability, and have the characteristics of high obfuscation coverage that can be stable at over 98% and preservation of compiler indicative Comments.
作者机构：
[Zhuofan Liao; Wenqiang Deng; Shiming He; Qiang Tang] School of Computer and Communication Engineering, Changsha University of Science and Technology, Changsha 410114, China
通讯机构：
[Zhuofan Liao] S;School of Computer and Communication Engineering, Changsha University of Science and Technology, Changsha 410114, China
摘要：
As Network Function Virtualization (NFV) continues to advance, Virtual Network Functions (VNFs) such as firewalls are increasingly used. Service Function Chains (SFCs) are formed by combining specific VNFs in a particular order, which are then deployed on the physical network to provide dedicated services to end users. Occasionally, partial VNF migration is employed to maintain service and network stability. However, decision-making times and system delays may become unacceptable due to the heterogeneous resource requirements of VNFs and the massive state migration of VNFs, especially in Multi-access Edge Computing (MEC) networks where resources are scarce and demand fluctuations are frequent. To solve these challenges, we first formulate the problem of Minimizing decision Time and system Latency for joint VNF Deployment and Migration (MTLDM) as a multi-objective optimization problem. Then, we propose a Collaborative Filtering-based Fast Delay-aware algorithm (CFFD) to solve this problem. In this algorithm, we introduce an innovative approach, referred to as the collaborative filtering-based method, which utilizes the preference information of deployed/migrated VNFs to assist the current VNF deployment/migration in reducing decision-making time. Additionally, we design a similarity-based method in CFFD to search for suitable hosts for the current VNF, thereby reducing the complexity caused by heterogeneity and minimizing system latency. Furthermore, we implement a heuristic method in CFFD to increase the number of accepted requests. In the end, extensive simulations are conducted to evaluate the performance of CFFD in comparison with baseline algorithms and to select the suitable similarity algorithm. The results of the selection simulation show that Manhattan distance and cosine similarity are superior to Pearson’s correlation. Moreover, the comparison simulation results indicate that CFFD outperforms the baseline algorithms in terms of delay optimization and decision time by up to 22.08% and 99%, respectively.
摘要：
The electronic properties of C2N/antimonene (Sb) van der Waals (vdW) heterostructure are investigated based on the density functional theory. The results show that the C2N/Sb vdW heterostructure behaves type-II band alignment with a direct Eg of 0.35 eV. The electronic structure can be adjusted by horizontal (vertical) strain, electric field, interlayer twist, and vertical strained-twisted cases, respectively. The horizontal strain shows a more extensive controlling range of Eg than the vertical strain, but the vertical strain adjusting shows better linear features than the horizontal strain. When applying an electric field, the maximum Eg can reach 1.4 eV with Type-I band alignment, which has potential in transistors, solar cells, Light Emitting Diode(LED), and other applications. The heterostructure keeps robust type-II band alignment with different twist angles between C2N and Sb monolayer, which contributes to efficient separation of photo-generated electron-hole pairs as photovoltaic and optical detector devices. When the vertical strain is applied on the twisted heterostructure, the band alignment, Eg, and energy states near the Fermi energy (EF) change obviously due to orbital hybridization strengthened. Our results suggest that there are various means to regulate the electronic properties of heterostructures.
作者机构：
[Long, Yun; Bao, Yude] Guangdong Power Grid Co Ltd, Guangzhou Power Supply Bur, Guangzhou 510260, Peoples R China.;[Zeng, Linjun] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha, Peoples R China.
通讯机构：
[Zeng, LJ ] C;Changsha Univ Sci & Technol, Sch Energy & Power Engn, Changsha, Peoples R China.
关键词：
power monitoring system;cloud-edge-device collaboration;large-scale digital substation;edge computing;intelligent patrol;intelligent operation;decision fusion
摘要：
With the continuous promotion of digital transformation in the field of power transformation, the diversification of application scenarios, and the scale of pilot construction, the real-time, concurrency, and security requirements for data fusion and application support of the power monitoring system, management information system, and other business platforms are getting higher and higher, and this paper puts forward a high concurrency and availability "cloud-side-end collaboration" based on edge computing. This paper proposes a high concurrency and availability "cloud, edge and end collaboration" architecture based on edge computing for substation operation support systems. First, this paper summarizes the development status of domestic substation operation support systems and analyzes the advantages and disadvantages of various technical architectures. Then, a "cloud-side-end cooperative" substation operation support system architecture with "high real-time, high concurrency, high security and high stability" is proposed, which focuses on remote inspection, remote operation, and remote safety control of substation businesses from the perspective of engineering applications. It realizes transparent monitoring of equipment operation, unified management of operation data, and integration of production command and decision-making; solves the problems of dispersed coexistence of multiple systems for dispatching, monitoring, analysis, management, and other businesses, switching between multiple systems, and insufficient real-time and stability of the system; and controls the risks of the grid, reduces the potential safety hazards, and solves the contradiction between the continuous growth of the grid equipment and the shortage of production personnel. The results of engineering application examples show that the proposed architecture compared with the existing system architecture has greater advantages and can meet the requirements of large-scale access to the substation, with feasible popularization and application.
摘要：
With the development of cities and population, the production of sludge is increasing annually. It has become an unavoidable challenge to achieve sludge dewatering and disposal by a cost-effective, efficient and safe process. In this work, firstly, the factors limiting sludge dewatering are reviewed in terms of moisture distribution, sludge concentration, organic matter content, electronegativity, floc strength, and extracellular polymers (EPS). Subsequently, focusing on the dewatering technology about the skeleton builder, the recent progress of it is detailed in terms of mechanism, evaluation indicators, influencing factors, and technology coupling. In addition, the impact of skeleton builders on the sludge disposal stage is concluded. Finally, the challenges faced by sludge dewatering and skeleton builders are prospected. This review will provide some theoretical basis and technical guidance for subsequent experiments and practices regarding skeleton builders.
