Highly Thermally Conductive and Structurally Ultra‑Stable Graphitic Films with Seamless Heterointerfaces for Extreme Thermal Management

Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme alternating thermal/cold shock poses a significant challenge to reliability and safety.Here,we present the first investigation into the structural failure mechanism of GF during cyclic liquid nitrogen shocks(LNS),which reveals a bubbling process characterized by“permeation-diffusion-deformation”phenomenon.To overcome this long-standing structural weakness,a novel metal-nanoarmor strategy is proposed to construct a Cu-modified graphitic film(GF@Cu)with seamless heterointerface.This well-designed interface ensures superior structural stability for GF@Cu after hundreds of LNS cycles from 77 to 300 K.Moreover,GF@Cu maintains high thermal conductivity up to 1088 W m^(−1)K^(−1)with degradation of less than 5%even after 150 LNS cycles,superior to that of pure GF(50%degradation).Our work not only offers an opportunity to improve the robustness of graphitic films by the rational structural design but also facilitates the applications of thermally conductive carbon-based materials for future extreme thermal management in complex aerospace electronics.

Research on Performance Optimization of Liquid Cooling and Composite Phase Change Material Coupling Cooling Thermal Management System for Vehicle Power Battery

The serpentine tube liquid cooling and composite PCM coupled cooling thermal management system is designed for 18650 cylindrical power batteries,with the maximum temperature and temperature difference of the power pack within the optimal temperature operating range as the target.The initial analysis of the battery pack at a 5C discharge rate,the influence of the single cell to cooling tube distance,the number of cooling tubes,inlet coolant temperature,the coolant flow rate,and other factors on the heat dissipation performance of the battery pack,initially determined a reasonable value for each design parameter.A control strategy is used to regulate the inlet flow rate and coolant temperature of the liquid cooling system in order to make full use of the latent heat of the composite PCM and reduce the pump’s energy consumption.The simulation results show that the maximum battery pack temperature of 309.8 K and the temperature difference of 4.6 K between individual cells with the control strategy are in the optimal temperature operating range of the power battery,and the utilization rate of the composite PCM is up to 90%.

Design and analysis of an advanced thermal management system for the solar close observations and proximity experiments spacecraft

In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relationship and functions of the integrated database,the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon.For the complex thermal field regulation system and extreme space thermal environment,a modular simulation and thermal field planning method are proposed,and the feasibility of the planning algorithm is verified by numerical simulation.A solar array liquid cooling system is developed,and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion.The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs.

Resource Integration,Risk Management and Liquidity Management Strategies

The financial impact caused by the pandemic has swept the world.So far,although China has made great achievements in fighting against the pandemic,production and living order has been restored,but enterprises have faced problems in operation and management after more than half a year.For example,low resource utilization rate,weak integration ability,insufficient risk awareness,blind expansion in disadvantaged situation,high risk of financial leverage,long enterprise business and so on.The following article will conduct research on resource integration,risk management and liquidity management,and provide suggestions for enterprises to survive the economic impact of the pandemic smoothly.

Liquid metal compartmented by polyphenol-mediated nanointerfaces enables high-performance thermal management on electronic devices

The exponentially increasing heat generation in electronic devices,induced by high power density and miniaturization,has become a dominant issue that affects carbon footprint,cost,performance,reliability,and lifespan.Liquid metals(LMs)with high thermal conductivity are promising candidates for effective thermal management yet are facing pump-out and surface-spreading issues.Confinement in the form of metallic particles can address these problems,but apparent alloying processes elevate the LM melting point,leading to severely deteriorated stability.Here,we propose a facile and sustainable approach to address these challenges by using a biogenic supramolecular network as an effective diffusion barrier at copper particle-LM(EGaIn/Cu@TA)interfaces to achieve superior thermal conduction.The supramolecular network promotes LM stability by reducing unfavorable alloying and fluidity transition.The EGaIn/Cu@TA exhibits a record-high metallic-mediated thermal conductivity(66.1 W m^(-1) K^(-1))and fluidic stability.Moreover,mechanistic studies suggest the enhanced heat flow path after the incorporation of copper particles,generating heat dissipation suitable for computer central processing units,exceeding that of commercial silicone.Our results highlight the prospects of renewable macromolecules isolated from biomass for the rational design of nanointerfaces based on metallic particles and LM,paving a new and sustainable avenue for high-performance thermal management.

Bifunctional Liquid Metals Allow Electrical Insulating Phase Change Materials to Dual-Mode Thermal Manage the Li-Ion Batteries

Phase change materials(PCMs)are expected to achieve dual-mode thermal management for heating and cooling Li-ion batteries(LIBs)according to real-time thermal conditions,guaranteeing the reliable operation of LIBs in both cold and hot environments.Herein,we report a liquid metal(LM)modified polyethylene glycol/LM/boron nitride PCM,capable of dual-mode thermal managing the LIBs through photothermal effect and passive thermal conduction.Its geometrical conformation and thermal pathways fabricated through ice-template strategy are conformable to the LIB’s structure and heat-conduction characteristic.Typically,soft and deformable LMs are modified on the boron nitride surface,serving as thermal bridges to reduce the contact thermal resistance among adjacent fillers to realize high thermal conductivity of 8.8 and 7.6 W m^(−1) K^(−1) in the vertical and in-plane directions,respectively.In addition,LM with excellent photothermal performance provides the PCM with efficient battery heating capability if employing a controllable lighting system.As a proof-of-concept,this PCM is manifested to heat battery to an appropriate temperature range in a cold environment and lower the working temperature of the LIBs by more than 10℃ at high charging/discharging rate,opening opportunities for LIBs with durable working performance and evitable risk of thermal runaway.

Development of ToSPACE for Pipe Wall Thinning Management in Nuclear Power Plants

A number of piping components in the secondary system of nuclear power plants are exposed to aging mechanisms such as FAC (Flow-Accelerated Corrosion), cavitation, flashing, SPE (Solid Particle Erosion), LDIE (Liquid Droplet Impingement Erosion), etc. Those mechanisms may lead to thinning, leak, or rupture of the components. Due to the pipe ruptures caused by wall thinning in Surry unit 2 of USA in 1986 and in Mihama unit 3 of Japan in 1994, the pipe wall thinning management has emerged as one of the most important issues in nuclear power plants. To manage the pipe wall thinning in the secondary system, Korea has used a foreign program since 1996. As using the foreign country’s program for long term, it was necessary to improve from the perspective of the users. Accordingly, KEPCO-E & C has started to develop the 3D-based pipe wall thinning management program (ToSPACE, Total Solution for Piping And Component Engineering management) from eight years ago, and the development was successful. This paper describes the major functions included in ToSPACE program, such as 3D-based DB (Database) buildup, development of FAC and erosion evaluation theories, UT (Ultra-sonic Test) data reliability analysis, field connection with 3D, automatic establishment of long-term inspection plan, etc. ToSPACE program was developed to allow site engineers performing the selection of inspection quantity at each refueling outage, UT data reliability analysis, UT evaluation, determination of next inspection timing, identification of the inspecting and replacing components in 3D drawings, etc., to access easily.

Nation Needs to Reform Its Foreign Exchange Reserves Management System

This article assesses both the domestic and external reasons for the occurrence of excessive liquidity.To solve the problem of excessive liquidity two different policy options are proposed;firstly the improvement of the structure of national income assignment and secondly the promotion of the structural diversification of foreign exchange assets.

Research on the Influencing Factors of Purchasing Internet Financial Wealth Management Products Based on AHP

Internet financial wealth management product(IFWMP)has recently been one of the most gained popularity.There are limited quantitative research on IFWMP which can help customers to choose products based on the significance of each factor.In this paper,a multi-criteria decision-making model for IFWMP was developed,namely the analytic hierarchy process(AHP)which is commonly used to make decisions for unstructured problems through quantifying weights of each criterion.This paper investigated ten influential factors relevant to the purchase of IFWMP and analyzed the frequency of collected response to show the significance of the factors.Based on the quantified weights,the results of the research indicated that compatibility,product liquidity,perceived ease of use,and perceived usefulness affected investors purchasing behaviors and that every investor should pay great attention to.

Research on the Influencing Factors of Purchasing Internet Financial Wealth Management Products based on AHP

Internet financial wealth management product(IFWMP)has recently been one of the most popularity.There is limited quantitative research on IFWMP which can helps customers to choose the products based on the significance of each factor.In the paper,a multi-criteria decision-making model of IFWMP was developed,namely analytic hierarchy process(AHP)which is used to make decisions to the unstructured problems through quantifying weights of each criterion.This paper investigated ten influential factors relevant to the purchase of IFWMP and analyzed the frequency of collected responds to show the significance of factors.Based on the quantified weights,the result of the research indicated that compatibility,product liquidity,perceived ease of use and perceived usefulness affect the investors purchasing behaviors most that every investors should pay great attention to.

化疗药物智能配药与运送系统的应用

目的 :应用化疗药物智能配药与运送系统并评价其应用效果,为保障患者用药安全和提高临床工作效率提供借鉴。方法 :采用现场观察法观察配药过程,比较人工与机器人冲配化疗药所需要的时间及药物残余量。比较化疗药物智能配药与运送系统使用前后人工与机器人冲配化疗药数量和配送化疗药次数。结果 :人工冲配每袋化疗药物时间长于机器人冲配时间(P<0.01),人工冲配药物残余量多于机器人(P<0.01)。机器人日均冲配化疗药数量多于人工(P<0.01)。机器人月均配送化疗药次数低于人工(P<0.01)。结论 :通过应用化疗药物智能配药与运送系统,可以提高给药精准度和工作效率,减少医务人员与化疗药接触频次,有利于降低职业损伤风险,值得推广应用。

动力电池温度集成控制系统设计与研究

本文以非公路机械动力锂电池为研究对象,围绕动力电池低温加热与高温散热两大关键环节,开展动力电池温度集成控制系统设计与研究。鉴于温度对电池性能及寿命的影响,本文采用挤压成型的铝制型材液冷板,长圆形冷却液道截面,并行布置于模组底部与侧面的方式,实现电池模组的多方向冷却。同时,在电池模组两侧加装电阻式加热片,可使低温下的电池快速升温至适宜温度,确保动力电池发挥良好的充放电性能。动力电池温度集成控制系统能够有效解决电池模组单体电芯温差过大等问题,为动力电池安全高效工作提供强有力保障。

有轨电车超级电容模组液冷散热仿真分析

超级电容模组因其快速充放电和适应大功率需求的能力被视为有轨电车未来动力电源的发展趋势。然而,在运行和充放电过程中,超级电容模组会产生大量热量,并导致温度在短时间内迅速上升。为解决该问题,本工作提出一种采用微型通道液体冷却的热管理方式,其原理是利用液冷板微型通道内的低温流体对超级电容单体进行冷却,通过改变边界条件确保超级电容模组在不同散热工况下的工作温度始终保持在适宜的范围内。为了比较液冷板性能,本工作设计了三种液冷板微型通道的模型,并使用ANSYS仿真软件对其进行了数值模拟,建立了新型液冷板最高温度预测模型,研究了边界条件对新型液冷板性能的影响。结果表明,design-3液冷板模型具有较好的流动和散热性能,当提高冷却液入口质量流量时,可以有效降低超级电容单体的最大温差和最高温度,改善单体间的均温性。但随着冷却液入口质量流量增至0.35 kg/s后,超级电容单体最高温度降幅逐渐减小,对其散热性能改善有限,提高流量会使热管理系统能量损失增加;当提高冷却液入口温度时,超级电容单体间温差不断减小,但冷却液入口温度对单体的均温性影响不大。

动力电池液冷系统设计及其场协同优化

主要针对纯电动汽车动力电池液冷系统参数进行设计及优化,建立电池组散热模型,对其在不同参数下放电过程中的热分布进行仿真。在热流协同性和冷却效果方面,运用场协同原理对冷却管道中的各个参数进行分析。仿真结果表明,冷却液初始温度、流速和入口分布均会对液冷系统冷却性能产生影响。根据条件设置,冷却液初始温度为15℃与流速为2L/min的液冷系统可有效提高电池组的冷却效果;冷却通道入口为3个时期冷却效果最佳,电池组温差为最小。

基于浸没式液冷的锂电池热管理研究进展

电池热管理系统对电动汽车的安全性至关重要。随着电池能量密度和放电功率的提高,传统散热方案已无法满足当前电池散热的要求。浸没式液冷电池热管理系统作为电动汽车动力电池组和动力系统的高效热管理解决方案之一,正受到越来越多的关注。本文综述了目前锂离子电池浸没式液冷技术,包括单相浸没式液冷和两相浸没式液冷;探讨了冷却液种类、排布方式、流速、压力等因素对系统性能的影响及浸没式液冷效率的评价方法。同时,分析了目前浸没式液冷技术在电池热管理中的行业趋势。最后,对于浸没式液冷在锂电池热管理中的应用进行了展望,为开发更高功率、更安全和更持久的电动汽车提供参考。

空间液氪气液分离装置流阻特性及数值模拟

为满足低温推进剂在空间微重力环境中的气液分离要求,针对液氪低温推进剂在轨管理与传输问题,建立筛网式气液分离装置单通道流动压力损失的理论预测模型,获取120 K饱和状态液氪在325×2300荷兰斜纹编织网中流动的泡破点压力。对比分析了不同低温流体、通道宽度、质量流量对过网压降的影响规律,获得了液氪在通道中流动的压降分布,并通过国外液氢过网压降实验数据对模型进行了验证。通过建立液氪单通道流动数值仿真模型,较好地预测了过网压力损失。

床旁超声参数在儿童脓毒性休克液体管理中的指导价值

目的探讨床旁超声在儿童脓毒性休克液体管理中的指导价值,并分析其对患儿临床预后的评估价值。方法选取2021年10月—2023年2月河北省儿童医院收治的60例脓毒性休克患儿,依据治疗方案分为两组,各30例。对照组予以目标导向的液体复苏治疗,观察组在对照组基础上予以床旁超声监测。比较两组不同时间血流动力学指标[心率(HR)、平均动脉压(MAP)、中心静脉压(CVP)]、床旁超声参数、组织灌注指标、乳酸、乳酸清除率、高迁移率族蛋白1(HMGB1)/白细胞介素(IL)-23/IL-17炎症轴、累计输液量、尿量、液体正平衡量等差异,并统计两组患者治疗28 d内病死率情况。结果观察组血管活性药物使用时间及剂量、机械通气时间、ICU入住时间及总住院时间少于对照组(均P<0.05);治疗6 h、12 h、24 h后两组HR、下腔静脉内径呼吸变异度明显下降,MAP及CVP、下腔静脉内径最大径、最小径及每搏输出量明显升高(P<0.05),但两组组间比较,差异无统计学意义(P>0.05);观察组治疗6 h、12 h、24 h HR、Pv-aCO_(2)低于对照组(均P<0.05);观察组治疗6 h、12 h、24 h乳酸低于对照组,乳酸清除率高于对照组(均P<0.05);观察组治疗6 h、12 h、24 h HMGB1、IL-23、IL-17水平低于对照组(均P<0.05);观察组治疗12 h、24 h液体正平衡量、累计输液量低于对照组,尿液高于对照组(均P<0.05);两组28 d病死率比较,差异无统计学意义(P>0.05)。结论床旁超声在儿童脓毒性休克液体管理方面具有一定指导价值,可改善患儿组织灌注指标,并降低减轻炎症反应,缩短患儿住院时间,有助于患儿病情缓解。

基于液冷通道优化的电池热管理实验研究

高效的热管理对高温下锂电池的安全性和均温性至关重要,提出采用Y型通道液冷板的新型液冷电池热管理系统。采用实验与仿真的方法研究冷却剂入口流速、通道宽度、入口温度等参数耦合对电池最高温度、最大温差以及冷却剂进出口压降的影响。结果表明:与无冷却装置的系统相比,Y型通道冷板的冷却性能提升了27.5%。在3C放电倍率下,电池表面最高温度可以控制在39.8℃内。入口流速越小,电池的均温性越低,当流速为0.1 m/s时,综合性能评价标准E_(I)指数提高了16%。通道宽度的设计需要平衡冷却性能及功耗,宽度为1.5 mm的通道具有最佳综合性能,与其他宽度相比,E_(I)指数最大提高了8.3%。在最高温度处于最佳温度范围时,入口温度为20℃,E_(I)指数达到最高值1.24,兼顾了均温性能及功耗。所提出的Y型通道液冷板可为电池液冷系统的热设计提供一定的参考。

相变材料和液冷结合的锂离子电池热管理性能优化

相变材料因其良好的控温能力在电池热管理中得到了广泛的研究,但在高温环境和高放电倍率下,单纯依靠相变材料很难满足热管理的要求。设计了相变材料和冷却板混合的电池热管理方式并对其进行数值模拟,与采用纯相变冷却进行了对比。分析了电池间距、冷却液入口速度对电池最高温度以及相变材料液化率的影响,并对充放电循环过程进行了探究。结果表明,在高温和高放电工况下,液冷的引入解决了因相变材料完全液化导致的电池温度恶化和中间电池热量累积的问题。相比于纯相变冷却,当冷却液速度为0.5 m/s时,混合冷却可将电池的间距减小至3 mm,继续增大冷却液的速度对热管理性能提升较小。同时,液冷板的加入可以减少首次充放电循环对后续循环过程的影响,增加电池的使用寿命。

液冷式锂电池储能系统高倍率调频应用研究

针对风光能源规模化接入电网造成的频率波动问题,提出了结合功率型锂电池及液冷式热管理的储能系统。基于实验测试获取了功率型锂电池的电热特性,结果表明高倍率工况下仅依靠自然对流散热不能满足电池合理工作温度需求。建立了液冷式热管理系统及其仿真模型,并通过数值仿真对4C倍率放电、不同流量以及实际AGC调频工况条件下系统热管理性能及电池热行为进行了分析。研究表明实际AGC调频工况下,电池间温差小于2℃,最高温度小于33℃,证明了液冷式热管理方案能够实现储能系统在高倍率调频工况下的长期稳定运行。