This study focused on analyzing the contamination status of groundwater around an oil depot in Fuxin by considering physicochemical indexes, potentially toxic elements (PTEs), and organic substances with reference to relevant standards. The hazard analysis using the Nemero contamination index and potential ecological hazard index method, aimed at determining the levels of PTEs and organic contaminants in the groundwater, revealed a mild ecological risk in the study area. A redundancy analysis-geographic information system employed to uncover the sources of PTEs in groundwater samples revealed two main components: the first comprised Cd, Zn, Mn, and Pb, which were mainly of anthropogenic origin (oil reservoir leakage), and the second component includes Cr, Hg and As, which may originate from anthropogenic and geological sources. Evaluation of the carcinogenic and noncarcinogenic risks associated with PTEs indicated high levels of the former in the study area. Finally, the correlation between organic pollutants and environmental factors and the natural attenuation trend was explored. This exploration aimed to provide a reference for groundwater contamination investigation, formulation for contamination prevention and control strategies in relevant demolition areas, and theoretical guidance and technical support for subsequent analysis and monitoring of field data.

External short circuit (ESC) faults pose severe safety risks to lithium-ion battery applications. The ESC process presents electric thermal coupling characteristics and becomes more complex when the batteries operate in large group, which often lead to serious consequences. Lacking the cognition of fault features improve the difficulty of fault diagnosis and assessment. In this study, the characterization of lithium-ion battery ESC is conducted based on a systematical ESC experimental study ranging from single cell ESC to module ESC. The electro-thermal coupling characteristics during ESC evolution process are depicted. Considering the uncertain fault conditions, the impacts of battery state of charge (SOC), ambient temperature, short circuit duration, and external resistance on ESC faults are analyzed. ESC of battery series module, ESC of series-parallel module, and local ESC within the series-parallel module are investigated. The root cause and evolution of fire in module ESC process are revealed, and then the characteristics of ESCs between single cell and module are compared. The proposed conclusions are potential to be used in the battery ESC prevention applications and improve the battery safety management.

While sodium metal batteries (SMBs) have received much notice because of their low cost and abundant resources, they also suffer from an uncontrollable growth of dendritic crystals during the charging/discharging processes. This paper reports using Hexafluorocyclotriphosphazene (HFPN) as a flame-retardant additive and film-forming additive for SMBs mixed with conventional NaPF6 in a carbonate-based electrolyte. (1) the self-extinguishing time of the electrolyte was tested and the flame retardant mechanism of the flame retardant additive was explained; (2) the growth of sodium dendrites in the symmetric cell during constant current charging and discharging was observed using in situ optical microscopy; (3) the stable formation of HFPN with solid electrolyte interface (SEI) was illustrated by Scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) characterization, and the excellent cycling performance of the sodium metal all-cell with Na3V2(PO4)3 as the positive electrode was demonstrated.

The purpose of this study was to explore the stimulation mechanism of low pulsed electric field (PEF) strength treatment to promote the growth metabolism of aerobic denitrifying bacteria Pseudomonas putida W207-14. The results indicated that compared with the control group, the strain W207-14 treated with PEF entered the logarithmic growth phase 5 h earlier, the growth time to reached the maximum cell optical density at 600 nm (OD600) of 1.935 +/- 0.04 was only 24 h, which shortened by half. With the reduction of growth time, the metabolic rate of the strain increased significantly, in which the removal efficiency of COD, NO3--N and TN was 97.67 +/- 1.12%, 90.34 +/- 0.73% and 90.13 +/- 0.10% in 24 h, respectively. The maximum nitrate removal rate increased from 3.49 mg/L/h to 7.53 mg/L/h. A large number of cells with simultaneous cell membrane damage and high physiological activity were observed by flow cytometry (FCM) in combination with fluorescence staining analysis, which confirmed the reversible electroporation on the cell membrane of strain W207-14 treated with PEF. Transcriptomic analysis indicated that PEF activated the highly significant differential expression of membrane porin (opdB, opdC, and oprB) and cytochrome oxidoreductase related genes (ccoP, ccoN, cioA and cioB) on the cell membrane, which promoted the transport of nutrients through the cell membrane and electron transfer during aerobic respiration and provided an explanation for the possible mechanism of PEF promoting the growth metabolism of strain W207-14 at the micro level. These results lay a foundation for the practical application of PEF enhanced aerobic denitrification technology.

Abstract This paper presents a virtual ski training system based on changes in environmental elements of ski resort. The aim of the system is to allow skiers to ski training without going to a ski resort, increase tactical training in the face of different environments and help skiers improve their performance. The system uses VR technology to construct a realistic ski training scenario. 5G cloud platform transmissions are connected to the actual ski resorts to obtain real-time environmental elements data to import into the VR system in order to construct a dynamic model of the environment. The effectiveness of the system was verified through a combination of indoor and outdoor tests to analyse participants' skiing speed in both real and virtual scenarios. In conjunction with questionnaires completed by the participants, differences in the effectiveness of the participants' experience of the different dimensions of the system were analysed. The results show that this VR system is effective in simulating actual ski resorts and is an effective aid for skiers, especially less experienced ski students.

In recent years, ski resorts have gradually become the first choice for people to travel and vacation in winter. But the current monitoring system of ski resorts is not mature and perfect. Therefore, this paper proposes a remote real-time monitoring system for ski resorts based on the CPS (information physical system) three-layer (physical layer, cyber layer and decision layer) theoretical model, combined with the B/S (browser/server) mode of computer technology. The physical layer uses embedded devices and sensors to gather information about the ski resorts. In the network layer, a web cloud server is built based on the ASP.NET Core framework to complete the data transmission. The decision-making layer uses the front-end development language to build a web human-computer interaction page for data display. This system can realize remote real-time monitoring of the ski resort meteorological data (temperature and humidity, wind speed and direction) and image information, which is the intelligent information of the ski resort monitoring system. Transformation provides actionable solutions.

External short circuiting (ESC) is a main source of battery faults. However, the ESC damage mechanism and its evolution process are unclear, resulting in difficulties in safety management. Here, we report the impact of different ESC durations on battery performance and divide the ESC process into four stages. The analysis reveals that there is a benign regime in which the ESC effect is comparable to nominal charge-discharge cycling. When ESC duration is close to a critical time, there is a benign-to-malignant transition. The critical time corresponds to the inflection point at the end of battery current curve, which reflects heating-induced membrane melting and contraction that distorts the jellyroll. The critical time surface under various conditions is established and the center temperatures of the critical time and battery completely failure are disclosed, paving the way for fault diagnosis and using "benign ESC" in a controlled fashion.

With the improvement of people's living standards and the increasing maturity of wireless transmission technology, smart home is further promoted and applied, but due to the imperfect development of smart home bureau, there are still many security risks, mainly in the lack of effective authentication mechanism, the security of authentication is not high; smart home devices have loopholes, smart devices have memory loopholes, logic loopholes; data security is not high, in the transmission The data security is not high, and it is easy to be stolen and listened to during the transmission. In this paper, based on data security aspects, combining previous research experiences and combining asymmetric and symmetric encryption algorithms, we propose a smart home data encryption system based on RSA + AES hybrid encryption to improve the communication security of each smart home.

动力电池环境适应性,尤其是低温性能受限严重制约新能源汽车在高寒地区的安全、耐久、高效和长里程运行。为解决动力电池低温预热难题,提出一种基于短时大电流自放电的电触发极速自加热方法,以18650类锂离子动力电池为研究对象,分析加热过程中的动力电池产热及温升特性,进而设计基于动力电池温度预测的极速加热控制策略;结合COMSOL仿真系统模拟动力电池加热效果,进而开发带有极速加热样机的测试平台,测试结果表明,该方法可以实现快达0.65℃/s的瞬时加热速率,在87 s内将动力电池从环境温度-20℃加热到20℃,目标温度的控制误差仅0.4%,且该加热方法对动力电池寿命的影响很小,对动力电池模组加热时温升标准差小于2.7℃。最后对该加热方法的应用前景、所需进一步解决的科学问题及研究路线进行探讨。

External short circuit (ESC) fault, which can cause large current and high temperature, is one of the main reasons for battery failure. Its analysis and diagnosis remains a challenging task due to complex electro-thermal characteristics of batteries under ESCs. In this paper, ESC experiments at various temperatures are conducted to investigate the impact of temperature on battery electro-thermal behaviors. Based on the analysis of the experimental data, heat generation inside a battery caused by ESC-induced high current and side reactions is modeled. The heat distribution and diffusion are also modeled by considering battery's internal jellyroll structure. The combination of the heat generation, distribution and diffusion models forms a novel electro-thermal coupling model, which is used to predict the complex thermal and electrical properties of a battery under ESCs. The presented model is simulated and verified by the test data. The maximum root mean square error of ESC current prediction is less than 1.73A and the maximum errors of the internal temperatures and the surface temperatures are only 1.771% and 3.915%, respectively. These results verify the effectivceness of the presented model. It is expected that the presented model is useful for safety analysis, temperature prediction and fault diagnosis applications of the lithium-ion batteries under ESC.

锂离子动力电池在低温环境下性能急剧衰退,制约了电动汽车在全气候范围内的推广应用.针对电触发极速加热系统:首先进行电热特性建模方法研究,开展电特性表征,建立考虑材料各向异性的电池产热及热扩散有限元模型,试验验证表明电流误差低于98.2 mA,温升误差小于4.09％;仿真研究不同占空比、电池初始SOC情况的加热特性,进而对电池组在加热过程中的加热行为一致性进行研究,结果表明可在270 s内从-20℃加热到20℃,最大温差低于3.94℃;分析电池单体不一致性与加热系统控制参数对加热行为一致性的影响特性,结果表明电池组温升不一致性与单体电池内阻标准差呈正线性相关,且受控制频率与占空比影响显著,其中占空比对温升影响幅度高达15％.

External short circuit (ESC) is one of the most ubiquitous faults that may occur during the battery utilization in electric vehicles (EVs). ESC causes the high temperature rise and may destroy the battery if it lasts long enough. However, the damage generation characters between the ESC occurrence and the battery destruction are not clear. In this study, the ESC characters under the varying duration time and the damage impacts are investigated. A novel experimental study on the ESC with incremental duration is proposed and the damage effects are analyzed via the changes of the battery characters, Secondly, the battery destruction is proved to be abruptly generated right after a critical time. The electrochemical mechanism implied with critical time is analyzed. Finally, the curved surface of the ESC critical time against the varying battery working conditions is disclosed.

随着新能源发电的快速发展和大规模并网运行,储能电站的应用越来越多.其中,锂电池储能电站配置的比例在逐年增加,但是,构成储能电站的大量单体电池之间不可避免的会存在差异,这种差异会随着时间的推移而加剧,最终严重影响储能电站的运行效果.为此,提出一种适用于大规模储能电站的基于DC/DC变换器的储能电站锂电池快速均衡策略,可以快速均衡目标电池组,并通过实验对快速均衡策略进行了实验验证,实验结果表明,提出的快速均衡策略是有效的,可以用于大型储能电站的快速均衡控制.

通过恒流放电和析气测试,研究LR6电池的室温150 mA恒流连放,室温、高温(60℃)小电流深放电性能.在室温下,IBC-4系列合金均具有较低的析气量,使用IBC-4-8合金的电池的放电性能最好.在室温下,电池中锌粉的利用率随着放电电流的减小而增加,总的析气量加大;高温20 mA、50 mA和80 mA恒流放电,锌粉利用率分别为99.29％、98.83％和94.62％.放电析气总量随着放电深度的增加而增加,对电池的安全性和稳定性有一定的影响.

State of charge (SOC) estimation is a key function of battery management system. This study examines the possibility of estimating the battery SOC under a certain short time External short circuit (ESC) process. Active short time ESC is sometimes useful in special applications that may not cause serious outcomes. The following contents are introduced in this papery. Firstly, ESC of cell experiment is designed under different SOC and temperatures. Then, genetic algorithm (GA) is used to identify model parameter, and SOC is estimated based adaptive extended Kalman filter (AEKF). It is illustrated that the presented SOC estimation can be well used in active ESC process with error less than 0.2%.