Solvation Engineering via Fluorosurfactant Additive Toward Boosted Lithium-Ion Thermoelectrochemical Cells

Lithium-ion thermoelectrochemical cell(LTEC), featuring simultaneous energy conversion and storage, has emerged as promising candidate for low-grade heat harvesting. However, relatively poor thermosensitivity and heat-to-current behavior limit the application of LTECs using LiPF_6 electrolyte. Introducing additives into bulk electrolyte is a reasonable strategy to solve such problem by modifying the solvation structure of electrolyte ions. In this work, we develop a dual-salt electrolyte with fluorosurfactant(FS) additive to achieve high thermopower and durability of LTECs during the conversion of low-grade heat into electricity. The addition of FS induces a unique Li~+ solvation with the aggregated double anions through a crowded electrolyte environment,resulting in an enhanced mobility kinetics of Li~+ as well as boosted thermoelectrochemical performances. By coupling optimized electrolyte with graphite electrode, a high thermopower of 13.8 mV K^(-1) and a normalized output power density of 3.99 mW m^(–2) K^(–2) as well as an outstanding output energy density of 607.96 J m^(-2) can be obtained.These results demonstrate that the optimization of electrolyte by regulating solvation structure will inject new vitality into the construction of thermoelectrochemical devices with attractive properties.

Regulating the Solvation Structure of Li^(+) Enables Chemical Prelithiation of Silicon-Based Anodes Toward High-Energy Lithium-Ion Batteries

The solvation structure of Li^(+) in chemical prelithiation reagent plays a key role in improving the low initial Coulombic efficiency(ICE) and poor cycle performance of silicon-based materials. Never theless, the chemical prelithiation agent is difficult to dope active Li^(+) in silicon-based anodes because of their low working voltage and sluggish Li^(+) diffusion rate. By selecting the lithium–arene complex reagent with 4-methylbiphenyl as an anion ligand and 2-methyltetrahydrofuran as a solvent, the as-prepared micro-sized Si O/C anode can achieve an ICE of nearly 100%. Interestingly, the best prelithium efficiency does not correspond to the lowest redox half-potential(E_(1/2)), and the prelithiation efficiency is determined by the specific influencing factors(E_(1/2), Li^(+) concentration, desolvation energy, and ion diffusion path). In addition, molecular dynamics simulations demonstrate that the ideal prelithiation efficiency can be achieved by choosing appropriate anion ligand and solvent to regulate the solvation structure of Li^(+). Furthermore, the positive effect of prelithiation on cycle performance has been verified by using an in-situ electrochemical dilatometry and solid electrolyte interphase film characterizations.

Recent Progress and Prospects on Dendrite-free Engineerings for Aqueous Zinc Metal Anodes

Rechargeable zinc-ion batteries with mild aqueous electrolytes are one of the most promising systems for large-scale energy storage as a result of their inherent safety,low cost,environmental-friendliness,and acceptable energy density.However,zinc metal anodes always suffer from unwanted dendrite growth,leading to low Coulombic efficiency and poor cycle stability and during the repeated plating/stripping processes,which substantially restrict their further development and application.To solve these critical issues,a lot of research works have been dedicated to overcoming the drawbacks associated with zinc metal anodes.In this overview,the working mechanisms and existing issues of the zinc metal anodes are first briefly outlined.Moreover,we look into the ongoing processes of the different strategies for achieving highly stable and dendrite-free zinc metal anodes,including crystal engineering,structural engineering,coating engineering,electrolyte engineering,and separator engineering.Finally,some challenges being faced and prospects in this field are provided,together with guiding significant research directions in the future.

In Situ Reaction Fabrication of a Mixed-Ion/Electron-Conducting Skeleton Toward Stable Lithium Metal Anodes

Lithium metal batteries are emerging as a strong candidate in the future energy storage market due to its extremely high energy density.However,the uncontrollable lithium dendrites and volume change of lithium metal anodes severely hinder its application.In this work,the porous Cu skeleton modified with Cu_(6)Sn_(5)layer is prepared via dealloying brass foil following a facile electroless process.The porous Cu skeleton with large specific surface area and high electronic conductivity effectively reduces the local current density.The Cu_(6)Sn_(5)can react with lithium during the discharge process to form lithiophilic Li_(7)Sn_(2)in situ to promote Li-ions transport and reduce the nucleation energy barrier of lithium to guide the uniform lithium deposition.Therefore,more than 300 cycles at 1 mA cm^(−2)are achieved in the half-cell with an average Coulombic efficiency of 97.5%.The symmetric cell shows a superior cycle life of more than 1000 h at 1 mA cm^(−2)with a small average hysteresis voltage of 16 mV.When coupled with LiFePO_(4)cathode,the full cell also maintains excellent cycling and rate performance.

Thermally Chargeable Proton Capacitor Based on Redox-Active Effect for Energy Storage and Low-Grade Heat Conversion

Thermal energy is abundantly available in our daily life and industrial production,and especially,low-grade heat is often regarded as a byproduct.Collecting and utilizing this ignored energy by low-cost and simple technologies may become a smart countermeasure to relieve the energy crisis.Here,a unique device has been demonstrated to achieve high value-added conversion of low-grade heat by introducing redox-active organic alizarin(AZ)onto N-doped hollow carbon nanofibers(N–HCNF)surface.As-prepared N–HCNF/AZ can deliver a high specific capacitance of 514.3 F g^(-1)(at 1 A g^(-1))and an outstanding rate capability of 60.3%even at 50 A g^(-1).Meanwhile,the assembled symmetric proton capacitor can deliver a high energy density of 28.0 Wh kg^(-1) at 350.0 W kg^(-1) and a maximum power density of 35.0 kW kg^(-1) at 17.0 Wh kg^(-1).Significantly,the thermally chargeable proton capacitors can attain a surprisingly high Seebeck coefficient of 15.3 mV K^(-1) and a power factor of 6.02µW g^(-1).Taking advantage of such high performance,a satisfying open-circuit voltage of 481.0 mV with a temperature difference of 54 K is achieved.This research provides new insights into construction of high value-added energy systems requiring high electrochemical performances.

Power Matching and Energy Efficiency Improvement of Hydraulic Excavator Driven with Speed and Displacement Variable Power Source

Mobile machinery energy efficiency and emission pollution are the national and worldwide issues. This paper contributes in solving these problems by applying a speed variable power source. Unfortunately, almost all of the speed variable systems have the dynamic response problem when the motor starts with full load or heavy load. To address this problem, a hydraulic accumulator is used to balance the load of the power source for assisting starting of the motor and a matching method combined with speed and displacement control of the pump is proposed to improve the energy efficiency and dynamic performance simultaneously under different working conditions. Also, the power source/valve combined control strategy of an independent metering system is designed to realize flow matching of the whole system. Firstly, a test system is established to study the dynamic performance and energy efficiency of the speed variable power source with an auxiliary accumulator. Working performance and energy consumption of the power source under different rotating speeds and different loads are studied. And then, the hydraulic excavator test rig with the proposed system is constructed. Furthermore, the working performance of the excavator with the speed-fixed and speed-variable strategy are studied comparatively. Results show that, compared with fixed-speed strategy, the electric power consumption during the idle period and partial load condition can be reduced about 2.05 kW and 1.37 kW. The energy efficiency of speed variable power source is about 40%-71%, which is higher than that of the fixed-speed power source by 3%–10%.

Niobium Tungsten Oxide in a Green Water‑in‑Salt Electrolyte Enables Ultra‑Stable Aqueous Lithium‑Ion Capacitors

Aqueous hybrid supercapacitors are attracting increasing attention due to their potential low cost,high safety and eco-friendliness.However,the narrow operating potential window of aqueous electrolyte and the lack of suitable negative electrode materials seriously hinder its future applications.Here,we explore high concentrated lithium acetate with high ionic conductivity of 65.5 mS cm−1 as a green“water-in-salt”electrolyte,providing wide voltage window up to 2.8 V.It facilitates the reversible function of niobium tungsten oxide,Nb18W16O93,that otherwise only operations in organic electrolytes previously.The Nb18W16O93 with lithium-ion intercalation pseudocapacitive behavior exhibits excellent rate performance,high areal capacity,and ultra-long cycling stability.An aqueous lithium-ion hybrid capacitor is developed by using Nb18W16O93 as negative electrode combined with graphene as positive electrode in lithium acetate-based“water-in-salt”electrolyte,delivering a high energy density of 41.9 W kg−1,high power density of 20,000 W kg−1 and unexceptionable stability of 50,000 cycles.

Electrochemical Proton Storage:From Fundamental Understanding to Materials to Devices

Simultaneously improving the energy density and power density of electrochemical energy storage systems is the ultimate goal of electrochemical energy storage technology.An effective strategy to achieve this goal is to take advantage of the high capacity and rapid kinetics of electrochemical proton storage to break through the power limit of batteries and the energy limit of capacitors.This article aims to review the research progress on the physicochemical properties,electrochemical performance,and reaction mechanisms of electrode materials for electrochemical proton storage.According to the different charge storage mechanisms,the surface redox,intercalation,and conversion materials are classified and introduced in detail,where the influence of crystal water and other nanostructures on the migration kinetics of protons is clarified.Several reported advanced full cell devices are summarized to promote the commercialization of electrochemical proton storage.Finally,this review provides a framework for research directions of charge storage mechanism,basic principles of material structure design,construction strategies of full cell device,and goals of practical application for electrochemical proton storage.

Nanohollow Carbon for Rechargeable Batteries:Ongoing Progresses and Challenges

Among the various morphologies of carbon-based materials,hollow carbon nanostructures are of particular interest for energy storage.They have been widely investigated as electrode materials in different types of rechargeable batteries,owing to their high surface areas in association with the high surface-to-volume ratios,controllable pores and pore size distribution,high electrical conductivity,and excellent chemical and mechanical stability,which are beneficial for providing active sites,accelerating electrons/ions transfer,interacting with electrolytes,and giving rise to high specific capacity,rate capability,cycling ability,and overall electrochemical performance.In this overview,we look into the ongoing progresses that are being made with the nanohollow carbon materials,including nanospheres,nanopolyhedrons,and nanofibers,in relation to their applications in the main types of rechargeable batteries.The design and synthesis strategies for them and their electrochemical performance in rechargeable batteries,including lithium-ion batteries,sodium-ion batteries,potassium-ion batteries,and lithium–sulfur batteries are comprehensively reviewed and discussed,together with the challenges being faced and perspectives for them.

规模化猪场非洲猪瘟采样检测关键点和常见误区

近年来,非洲猪瘟疫情对国内养猪业的冲击很大,严重影响了大中小型规模化猪场的发展和利润,也给养猪业造成了巨大的损失。然而,随着非洲猪瘟病毒自然和非自然变异株的大量出现,对ASFV传统采样和检测须得到一些新技术的支持,如“唾液/深咽拭子+血液”抗原抗体同步采样检测、多重PCR以及微滴数字PCR等。基于此,文章归纳总结了规模化猪场采样和检测的关键点和常见误区,以期为国内规模化猪场现场采样和检测方面提供理论借鉴。

Dual-filler reinforced PVDF-HFP based polymer electrolyte enabling high-safety design of lithium metal batteries

Despite the high energy density of lithium metal batteries(LMBs),their application in rechargeable batteries is still hampered due to insufficient safety.Here,we present a novel flame-retardant solid-state electrolyte based on polyvinylidene fluoride-hexafluoropropylene(PVDF-HFP)with nano SiO_(2)aerogel as an inert filler but Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)as an auxiliary component to enhance the ion conductivity.The introduction of SiO_(2)aerogels imparts the polymer electrolyte with exceptional thermal stability and flame retardancy.Simultaneously,the interaction between hydroxyl groups of SiO_(2)particles and PVDF-HFP creates a strong cross-linking structure,enhancing the mechanical strength and stability of the electrolyte.Furthermore,the presence of SiO_(2)aerogel and LLZTO facilitates the dissociation of lithium salts through Lewis acid-base interactions,resulting in a high ionic conductivity of 1.01×10^(−3)S·cm^(−1)and a wide electrochemical window of~5.0 V at room temperature for the prepared electrolytes.Remarkably,the assembled Li|Li cell demonstrates the excellent resistance to lithium dendrite and runs stablly for over 1500 h at a current density of 0.25 mA·cm^(−2).Thus,we prepare a pouch cell with high safety,which can work normally after short-circuiting under the external folding and cutting.

Hypoxia inducible factor-1α related mechanism and TCM intervention in process of early fracture healing

As a common clinical disease, fracture is often accompanied by pain, swelling, bleeding as well as other symptoms and has a high disability rate, even threatening life, seriously endangering patients’ physical and psychological health and quality of life. Medical practitioners take many strategies for the treatment of fracture healing, including Traditional Chinese Medicine(TCM). In the early stage of fracture healing,the local fracture is often in a state of hypoxia, accompanied by the expression of hypoxia inducible factor-1α(HIF-1α), which is beneficial to wound healing. Through literature mining, we thought that hypoxia, HIF-1α and downstream factors affected the mechanism of fracture healing, as well as dominated this process. Therefore, we reviewed the local characteristics and related signaling pathways involved in the fracture healing process and summarized the intervention of TCM on these mechanisms,in order to inspirit the new strategy for fracture healing, as well as elaborate on the possible principles of TCM in treating fractures based on the HIF molecular mechanism.

基于启发式时空图神经网络的多变量时序异常检测

针对信息物理系统的多变量时序数据的异常检测是预防系统故障、保证安全生产的必要手段.由于系统变量间的强耦合性和传播效应,设计异常检测算法时应考虑系统变量间的耦合特性、传播有向性和因果时滞性,从系统结构变化的角度检测早期异常.本文提出一种端到端的启发式时空图神经网络(heuristic spatio-temporal graph neural network, HST-GNN)用于多变量时序数据的异常检测.首先,考虑变量间关系的有向性和集群性,设计一种有向相似性函数和基于启发式聚类算法的图结构学习算法,对多变量时序数据进行图建模以学习变量间的空间耦合关系;其次,使用门控卷积注意单元和多头图注意层作为时空图注意模块,从时空层面同时捕获系统的非线性因果时序和空间耦合深度特征;最后,量化系统的图结构特征,将其作为时空图网络提取的传感器深度特征的补充,输入自编码器中,从系统级别和传感器级别来检测异常.本文在4个公共数据集上验证了HST-GNN的性能.实验结果表明,稀疏有向的图结构有利于系统耦合特性的提取,从系统和传感器级别检测异常增加了模型对不显著的早期异常的敏感度.

A preliminary experimental investigation on the biotribocorrosion of a metal-on-polyethylene hip prosthesis in a hip simulator

Corrosion at the taper/trunnion interface of total hip replacement(THR)often results in severe complications.However,the underlying mechanisms of biotribocorrosion at the taper/trunnion interface during the long-term walking gait cycles remain to be fully understood.In this study,a hip joint simulator was therefore instrumented with an electrochemical cell for in-situ monitoring of the tribocorrosion evolution in a metal-on-polyethylene(MoP)THR during a typical long-term walking gait.In addition,the biotribocorrosion mechanism was investigated via surface and chemical characterizations.The experimental results confirmed that the taper/trunnion interface dominated the contemporary MoP hip joint corrosion.Three cyclic variations in the open circuit potential(OCP)were observed throughout the long-term electrochemical measurements,attributed to the formation and disruption of the adsorbed protein layer.The corrosion exhibited an initial increase at each period,peaking at approximately 0.125 million cycles,followed by a subsequent gradual reduction.Surface and chemical analyses revealed the formation of a tribochemical reaction layer(tribolayer)on the worn surface of the taper/trunnion interface.The surface/chemical characterizations and the electrochemical measurements indicated that the adhesion force of the adsorbed protein layer was weaker than that of the tribolayer.In contrast,the opposite was true for the corrosion resistance.Based on the observations from this study,the tribocorrosion mechanism of the taper/trunnion interface under the long-term walking gait cycles is deduced.

磁吻合技术及应用

磁外科(磁外科学)作为一门新兴的技术型学科,以其广泛的应用前景得到了全世界众多研究者的关注.磁外科技术按照其应用方式和原理的不同分为以下5大类:磁压榨技术、磁导航技术、磁锚定技术、磁悬浮技术以及磁示踪技术.其中,磁压榨技术利用磁力的特殊性质来完成临床上某些特定的操作,如脏器的连接再通、组织的压榨闭合、管腔内容物的限流等.磁吻合技术作为磁压榨技术的重要分支,其本质是利用磁力代替缝线和钛钉的牵拉力来完成组织管腔吻合或再通的技术.目前,磁吻合在临床中主要应用于以下3个领域:消化道管腔吻合、消化道闭塞/狭窄的再通以及血管吻合.磁力消化道管腔可应用于不同消化道管腔之间的吻合,将消化道管腔吻合由传统的"贯穿式"吻合转变成"非贯穿"吻合,极大地简化了操作,降低了术后并发症.针对消化道管腔闭塞/狭窄疾病,磁吻合技术为此类疾病提供了一种新的治疗策略,无需通过开腹或者开胸便可完成管腔的再通,极大地减轻了病人的创伤以及手术相关并发症的发生,甚至可以为某些传统方法无法治疗的疾病提供解决方案.除此之外,磁吻合技术还可应用于血管的端-端、端-侧以及侧-侧吻合,吻合过程操作简便,可在极短的时间内完成器官血流的重建,缩短了靶器官的缺血或瘀血时间,使得术后并发症显著减少,该技术已在冠脉搭桥、门腔分流以及器官移植等手术中成功应用.磁性装置的表面改性处理以及外形设计是磁吻合技术在临床应用的两大关键问题.磁性装置的表面改性方案主要取决于其在生物体内停留的时间,而磁性装置的外形设计主要取决于拟吻合管腔局部的解剖因素和磁体导入途径以及吻合所需要的磁力大小.鉴于磁吻合技术在管腔吻合以及管腔闭塞疏通中的巨大应用潜质,未来磁吻合技术将在为其他腔道(输尿管、尿道等)吻合或疏通方面提供新的治疗策略.

他克莫司个体内高变异度与肝移植术后免疫介导移植物损伤的临床研究

目的探讨他克莫司个体内变异度(IPV)与肝移植术后免疫介导移植物损伤的关系。方法回顾性分析2015年1月至2019年12月在西安交通大学第一附属医院肝胆外科进行经典原位肝移植的288例受者资料。采用移植后2~6个月期间至少5个他克莫司血药浓度谷值(C0)计算得到他克莫司血药浓度变异系数(CV)。设定的复合终点包括:(1)肝移植术后6个月后免疫介导的移植物失功,包括慢性排斥反应、活检证实的晚期急性排斥反应;(2)肝移植术后6个月后免疫抑制剂毒性作用导致的肝功能损害;(3)肝移植术后6个月后出现的CMV血症。以CV均值为临界值将受者分为低CV组和高CV组,比较两组到达复合终点的受者比例,分析肝移植术后发生免疫介导移植物损伤的影响因素。正态分布计量资料以均数±标准差(±s)表示,采用独立样本t检验进行比较;非正态分布计量资料以中位数表示,采用Mann-Whitney U检验进行比较。计数资料以例数(%)表示,采用χ^(2)检验进行比较。采用Kaplan-Meier法绘制生存曲线,使用log-rank检验进行比较。采用Cox比例风险模型分析肝移植术后免疫介导移植物损伤的危险因素,将单因素分析中P≤0.20的变量采用逐步后退法进行多因素分析。P<0.05为差异具有统计学意义。结果截至2021年6月30日,288例肝移植受者平均随访时间(37±16)个月(6~76个月),共37例(12.85%)到达复合终点。肝移植术后2~6个月他克莫司血药浓度CV平均值为(28.11±10.72)%,以28.11%作为临界值将288例受者分为低CV组(CV<28.11%)和高CV组(CV≥28.11%)。两组供者年龄、性别,受者年龄、性别、体质指数、原发病性质、术前终末期肝病模型评分、术前Child-Pugh评分、术后免疫抑制方案、慢性排斥反应发生率以及术后2~6个月他克莫司C0、总胆红素和ALT水平差异均无统计学意义(P均>0.05)。高CV组受者急性排斥反应和CMV血症发生率高于低CV组受者(3.13%和0,5.47%和1.25%),差异有统计学意义(P均<0.05)。高CV组到达复合终点的受者比例较低CV组高,分别为18.0%(23/128)和8.8%(14/160),差异有统计学意义(χ^(2)=5.397,P<0.05)。高CV组受者较低CV组到达复合终点的受者时间更短,分别为(1764±72)d和(1909±51)d,差异有统计学意义(χ^(2)=6.367,P<0.05)。Cox比例风险模型分析结果显示,供者年龄、移植前受者Child-Pugh评分、移植后2~6个月总胆红素和他克莫司血药浓度CV是肝移植术后发生免疫介导移植物损伤的独立危险因素(HR=1.033、2.353、1.011和0.450,P均<0.05)。结论肝移植术后2~6个月他克莫司高IPV(血药浓度CV≥28.11%)与免疫介导的移植物损伤存在显著相关性,可能导致急性排斥反应及CMV血症发生率增高。

Absorption mechanism of carbon-nanotube paper- titanium dioxide as a multifunctional barrier material for lithium-sulfur batteries

Lithium-sulfur batteries attract much interest as energy storage devices for their low cost, high specific capacity, and energy density. However, the insulating properties of sulfur and high solubility of lithium polysulfides decrease the utilization of active materials by the battery resulting in poor cycling performance. Herein, we design a multifunctional carbon-nanotube paper/titanium-dioxide barrier which effectively reduces active material loss and suppresses the diffusion of lithium polysulfides to the anode, thereby improving the cycling stability of lithium-sulfur batteries. Using this barrier, an activated carbon/sulfur cathode with 70% sulfur content delivers stable cycling performance and high Coulombic efficiency （-99%） over 250 cycles at a current rate of 0.5 C. The improved electrochemical performance is attributed to the synergistic effects of the carbon nanotube paper and titanium dioxide, involving the physical barrier, chemical adsorption from the binding formation of Ti-S and S-O, and other interactions unique to the titanium dioxide and sulfur species.

A review of the bio-tribology of medical devices

Numerous medical devices have been applied for the treatment or alleviation of various diseases.Tribological issues widely exist in those medical devices and play vital roles in determining their performance and service life.In this review,the bio-tribological issues involved in commonly used medical devices are identified,including artificial joints,fracture fixation devices,skin-related devices,dental restoration devices,cardiovascular devices,and surgical instruments.The current understanding of the bio-tribological behavior and mechanism involved in those devices is summarized.Recent advances in the improvement of tribological properties are examined.Challenges and future developments for the prospective of bio-tribological performance are highlighted.

Faraday anomalous dispersion optical filter at 133Cs weak 459 nm transition

A 459 nm Faraday anomalous dispersion optical filter（FADOF） working at the side wings of the cesium6S1∕2→ 7P1∕2transition with weak oscillator strength is achieved. The transmittance of the higher side wing reaches 98% at a temperature of 179°C and magnetic field above 323 G. The experimental results coincide with the theoretical predictions in 1982 and 1995, which were not realized in experiments for over three decades. Due to its high transmittance, high accuracy, and narrow linewidth, the 459 nm FADOF can be applied in underwater optical communications, the building of active optical clocks, and laser frequency stabilization in active optical clocks.

Template-Free Synthesis of Ordered Mesoporous NiO/Poly (Sodium-4-Styrene Sulfonate) Functionalized Carbon Nanotubes Composite for Electrochemical Capacitors

We report the first example of a practical and efficient template-free strategy for synthesizing ordered mesoporous NiO/poly(sodium-4-styrene sulfonate)(PSS)functionalized carbon nanotubes(FCNTs)composites by calcining a Ni(OH)_(2)/FCNTs precursor prepared by refl uxing an alkaline solution of Ni(NH_(3))x^(2)+and FCNTs at 97 oC for 1 h.The morphology and structure were characterized by X-ray diffraction,scanning electron microscopy,and transmission electron microscopy.Thermal decomposition of the precursor results in the formation of ordered mesoporous NiO/FCNTs composite(ca.48 wt%NiO)with large specifi c surface area.Due to its enhanced electronic conductivity and hierarchical(meso-and macro-)porosity,composite simultaneously meets the three requirements for energy storage in electrochemical capacitors at high rate,namely,good electron conductivity,highly accessibleelectrochemical surface areas owing to the existence of mesopores,and efficient mass transport from the macropores.Electrochemical data demonstrated that the ordered mesoporous NiO/FCNTs composite is capable of delivering a specifi c capacitance(SC)of 526 F/g at 1 A/g and a SC of 439 F/g even at 6 A/g,and show a degradation of only ca.6%in SC after 2000 continuous charge/discharge cycles.