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A novel carbonized phenolic formaldehyde resin (PF) resin-coated Ni foam was used as an interlayer for brazing carbon fiber reinforced carbon composites (C/C) and Nb using a Ti–Ni filler. At first, uniformly distributed carbonaceous laminae with different mass fractions on the Ni foam surface were acquired after the carbonization process by controlling the concentration of the PF solution. Afterwards, the obtained carbonaceous laminae covered Ni foam composite (C-Nif) was applied as an interlayer for brazing C/C and Nb via an assembly of C/C/Ti foil/Ni foil/C-Nif interlayer/Ti foil/Nb. The morphologies and microstructures of the carbonization product and the interfacial microstructures of the joints were investigated. The brazing mechanism has been elaborated in detail. With the help of the interconnected porous structure of the Ni foam, the distribution of the in-situ formed (Ti,Nb)2Ni particles, (Ti,Nb)C ring reinforcements as well as the Nb solid solution were uniformly obtained throughout the brazing seam. As a result, the joint residual stress was effectively released and consequently, the joint shear strength at elevated temperature (1000 °C) reached up to 33 MPa, which is 4.5 times higher than the directly brazed joint without an interlayer.

Increasing the electrochemical stability window and working temperature range of supercapacitor aqueous electrolyte is the major task in order to advance aqueous electrolyte-based supercapacitors. Here, a supramolecular induced new electrolyte of lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) in dimethyl sulfoxide (DMSO) and water co-solvent system is proposed. Adjusting the coordination structure among LiTFSI, DMSO, and water in the electrolyte via supramolecular interactions results in its high ionic conductivity, low viscosity, wide electrochemical stability window, and large working temperature range. The new electrolyte-based supercapacitors can work in 2.40 V working potential and 130 °C working-temperature range from −40 to 90 °C. The devices exhibit good electrochemical performances, especially the energy density over 21 Wh kg−1, which is much higher than that with traditional aqueous electrolytes (

The aim of this study was to compare the correlation of gamma-glutamyl transpeptidase-to-platelet ratio (GPR), aspartate aminotransferase-to-platelet ratio index (APRI), fibrosis index-4 (FIB-4), and liver stiffness measurement (LSM) in the diagnosis of liver fibrosis, and perform a diagnostic value of GPR for predicting fibrosis in CHB patients with NAFLD.A retrospective study was conducted on CHB patients concurrent with NAFLD between September 2019 and December 2020. They were divided into control group (LSM ≤ 9.7 kpa) and fibrosis group (LSM ≥ 9.8 kpa). Demographic data were collected; ALT, AST, and PLT were also detected. LSM was measured by transient elastography (TE). The GPR, APRI, and FIB-4 were calculated. The correlation between GPR, APRI, FIB-4, and LSM was compared. The accuracy of predicting liver fibrosis using GPR, APRI, and FIB-4 was assessed.Eighty-five CHB patients with NAFLD were enrolled. Multivariate analysis showed that age (p = 0.005), GGT (p = 0.001), and PLT (p = 0.013) were the independent risk factors for LSM. The GPR (p = 0.008), APRI (p = 0.001), and FIB-4 (p = 0.001) values in fibrosis group were higher than control group. Pearson linear correlation was used to analyze the correlations between LSM and GPR, APRI, and FIB-4. LSM was correlated with GPR, APRI, and FIB-4. The AUCs of GPR, APRI, and FIB4 were 0.805, 0.766, and 0.826 in assessing liver fibrosis, respectively. No significant differences in the areas of GPR were comparable to that of APRI and FIB-4.GPR has a good correlation with LSM in assessing liver fibrosis and can be used as a noninvasive index for the assessment of liver fibrosis in patients with concomitant CHB and NAFLD.

The growing popularity of quasi-solid-state supercapacitors inevitably leads to the unrestricted consumption of commonly used petroleum-derived polymer electrolytes, causing excessive carbon emissions and resulting in global warming. Also, the porosity and liquid electrolyte uptake of existing polymer membranes are insufficient for well-performed supercapacitors under high current and long cycles. To address these issues, poly(lactic acid) (PLA), a widely applied polymers in biodegradable plastics is employed to fabricate a renewable biocomposite membrane with tunable pores with the help of non-solvent phase inversion method, and a small amount of poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) is introduced as a modifier to interconnect with PLA skeleton for stabilizing the porous structure and optimizing the aperture of the membrane. Owing to easy film-forming and tunable non-solvent ratio, the porous membrane possesses high porosity (ca. 71%), liquid electrolyte uptake (366%), and preferable flexibility endowing the GPE with satisfactory electrochemical stability in coin and flexible supercapacitors after long cycles. This work effectively relieves the environmental stress resulted from undegradable polymers and reveals the promising potential and prospects of the environmentally friendly membrane in the application of wearable devices.

Recently, materials with hierarchical nanoporous architectures have been proposed to enhance the performance of alloy-type lithium-ion battery (LIB) and sodium-ion battery (SIB) anodes. However, th...

Traditional liquid lithium-ion batteries are not applicable for extreme temperatures, due to the shrinkage of separators and volatility of electrolytes. It is necessary to develop advanced electrolytes with desirable characteristics in terms of thermal stability, electrochemical stability and mechanical properties. Solid-state electrolytes, such as polyethylene oxide (PEO), outperform other types and bring the opportunity to realize the high-temperature lithium-ion batteries. However, the softness of PEO at elevated temperatures leads to battery failure. In this work, a three-dimensional fiber-network-reinforced PEO-based composite polymer electrolyte is prepared. The introduced polyimide (PI) framework and trimethyl phosphate (TMP) plasticizer decrease the crystallinity of PEO and increase the ionic conductivity at 30 °C from 8.79 × 10

It is found that crystalline nanoporous Ge can only partially store sodium, with amorphous NaxGe as the sodiation product. Electrochemical dilatometry techniques were used to measure the corresponding (de)sodiation-induced strains. The capacity and strain amplitude were found to exhibit the same decay trend during long-term cycling, which is expected since the capacity fades because of the volume changes arising during cycling. However, viewed from a different perspective, the similarity between capacity fading and strain decay suggests that one way to mitigate this capacity fading might be by preventing the initial strain from decaying, instead of getting rid of this strain.

Integrating carbon-coating and nanostructuring has been considered as the most promising strategy to accommodate the dramatic volume expansion represented by high-capacity antimony (Sb) upon sodiation. Suitable coating source and synthetic strategy that are both economical and strong are yet to be explored. In this regard, by using renewable bio-oil as carbon source and self-wrapping precursor, robust Sb@C composite anode with Sb nanoparticles homogeneously impregnated into the cross-linked 2D ultrathin carbon nanosheets is developed via a facile NaCl template-assisted self-assembly and followed carbothermal reduction method. Such judiciously crafted interconnected macroporous framework can mitigate of mechanical stress and alleviate the volume change of inner Sb, guaranteeing high-performance sodium-ion battery anode. At a current density of 0.1 A g−1, ultrahigh reversible capacity of 520 mAh g−1 can be achieved. Notably, a stable capacity of 391 mAh g−1 is even retained after 500 cycles at 1 A g−1. Such a facile and cost-effective synthetic method is promising for high-performance sodium-ion batteries.

Epoxy composites comprising modified graphene oxide and copper nanowires as hybrid fillers were prepared, in which dopamine (DA) is used as modifier for copper nanowires and graphene oxide (GO). Dopamine is easily oxidized to self-polymerize into adherent polydopamine (PDA) coating on all sorts of substrates in alkaline aqueous solution. In this paper, CuNWs@PDA and GO@PDA have been prepared successfully and confirmed by TEM, SEM and XRD, which indicates that the coating layer of PDA is uniformly capped on the copper nanowires and GO nanosheets. Meanwhile, the properties of epoxy composite were obtained by testing the thermal properties, volume resistivity and dielectric constant. The different proportions of hybrid fillers prepared by two modified fillers result in different thermal conductivities and other properties. The experimental results show that the epoxy composites possess higher thermal conductivity for 0.36 W/m K and excellent electrical insulation properties when the proportion of filler CuNWs@PDA:GO@PDA is 7:3. This is mainly attributed to the good interfacial adhesion between CuNWs@PDA/GO@PDA and resin as well as the synergetic effect between CuNWs@PDA and GO@PDA.

A novel 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) functionalized hyperbranched polysiloxane (HBPEp-DOPO) with considerable epoxy groups was synthesized. The structure was characterized by Fourier transform infrared (FTIR) spectra and nuclear magnetic resonance (1H-NMR). HBPEp-DOPO was then introduced into O,O’-diallylbisphenol A/4,4′-bismaleimidodiphenyl methane(DBMI) resin to develop modified composite with excellent dielectric and thermal properties as well as simultaneously improved comprehensive performance. The incorporation of HBPEp-DOPO not only remarkably increased the dielectric, mechanical, and thermal properties, but also obviously improved the flame retardancy. Compared with neat DBMI resin, HBPEp-DOPO/DBMI resins exhibited decreased dielectric loss with increasing the content of HBPEp-DOPO. Besides, adding 10 wt% HBPEp-DOPO could change the UL-94V of DBMI from V-2 to V-0. Moreover, HBPEp-DOPO/DBMI exhibited an improved mechanical property and thermal stability at a small addition amount. These attractive features allows the modified hyperbranched polysiloxane to have broad potential applications in cutting-edge industries, especially in electronic and electric insulating fields.

A thermally conductive epoxy polymer composite comprising copper nanowires and reduced graphene oxide as hybrid fillers was prepared. The synthesized one-dimensional copper nanowires (CuNWs) with excellent thermal conductivity and easy dispersity performed a thermal bridge to connect different layers of dimensional graphene oxide (GO), which benefited the thermal conductivity of epoxy composite conductor with increasing hybrid filler loading. The microstructure and morphology of hybrid fillers as well as the thermal properties, volume resistivity and dielectric constant of epoxy polymer composite were investigated. The TEM of hybrid fillers confirmed that CuNWs were loaded on the NH2-rGO uniformly and the CuNWs/NH2-rGO/epoxy possessed higher thermal conductivity and lower volume resistivity (the thermal conductivity and volume resistivity were about 0.43 W/(m · K) and 2.69 × 1011 Ω · cm, respectively) compared to CuNWs/epoxy polymer composite and NH2-rGO/epoxy polymer composite. Moreover, the CuNWs/NH2-rGO/epoxy composites presented better dielectric constant. These were all contributed to the synergetic effect between CuNWs and rGO.

Brazing C/C composites to Nb is often associated with high residual stress in this research, which results in low-strength joints. To overcome this problem, here we report a novel type of three-dimensional graphene-reinforced Cu foam (G-Cu foam) composite fabricated using chemical vapor deposition. This G-Cu foam was used as an interlayer for brazing C/C composite and Nb. Results show that high-quality graphene was evenly introduced in the brazing seam without agglomeration with the help of Cu foam substrate, which has a porous structure with an interconnected 3D scaffold. Moreover, wetting analyses revealed that the obtained graphene played a key role in retarding the metal atoms diffusion and consequently impeding the collapse of the Cu foam skeleton at brazing temperature. Furthermore, the extremely low coefficient of thermal expansion (CTE) of graphene and the good plastic deformation capacity of Cu foam are both conducive to reducing the thermal residual stress during the cooling process. By exerting the synergistic strengthening effect of both graphene and Cu foam, the brazed joint was effectively enhanced. The average shear strength of the joint brazed with G-Cu foam interlayer is ∼43 MPa.

The increasing popularity of Li-ion batteries in new applications such as electric vehicles is expected to cause the key resources (Li, Ni and Co) used in these batteries to become scarce. Alternative battery technologies, including Mg-ion, Na-ion, and metal-air batteries are therefore desirable. In this talk, I will discuss the use of operando wide-angle X-ray scattering (WAXS) to study the crystalline to amorphous phase transformations that are key to the outstanding performance of state-of-the-art alloy-type Mg- and Na-ion anodes. The 1st part of the talk will be on the impact of the crystalline-to-amorphous transformation on batteries cycle life. Here I will discuss our novel self-healing Ga/Mg anode, which holds the current record for cycle performance and rate capability in alloy-type Mg-ion battery anodes, owing to a crystalline Mg2Ga5 to amorphous liquid Ga phase transformation occurring near room temperature, preventing the well-known pulverization issue in alloy-type anodes.[1] The 2nd part of the talk will detail the impact of the crystalline-to-amorphous transformation on the rate capabilities of batteries. Here, I will present our nanoporous Sb/Na system, which transforms from crystalline Na3Sb to crystalline Sb, going through an amorphous intermediate. It will be shown using a combination of WAXS, electrochemical characterization, and computational study based on ab initio grand canonical (aiGCMC) simulations that the amorphous intermediate phase favors high rate Na storage in Sb.[2] [1] Wang, L., Welborn, S. S., Kumar, H., Li, M., Wang, Z., Shenoy, V. B., Detsi, E.: High‐Rate and Long Cycle‐Life Alloy‐Type Magnesium‐Ion Battery Anode Enabled Through (De)magnesiation‐Induced Near‐Room‐Temperature Solid–Liquid Phase Transformation. Adv. Energy Mater. 2019, 1902086. https://doi.org/10.1002/aenm.201902086 [2] M. Li, T. Qiu, S. Welborn, A. Foucher, B. Lesel, E. Stach, A. M. Rappe, E. Detsi: Understanding the Fast Kinetics of Sodium Storage in Antimony (unpublished)

The increasing popularity of Li-ion batteries in new applications such as electric vehicles is expected to cause the key resources (Li, Ni and Co) used in these batteries to become scarce. Alternative battery technologies, including Mg-ion, Na-ion, and metal-air batteries are therefore desirable. In this talk, I will discuss the use of operando wide-angle X-ray scattering (WAXS) to study the crystalline to amorphous phase transformations that are key to the outstanding performance of state-of-the-art alloy-type Mg- and Na-ion anodes. The 1st part of the talk will be on the impact of the crystalline-to-amorphous transformation on batteries cycle life. Here I will discuss our novel self-healing Ga/Mg anode, which holds the current record for cycle performance and rate capability in alloy-type Mg-ion battery anodes, owing to a crystalline Mg2Ga5 to amorphous liquid Ga phase transformation occurring near room temperature, preventing the well-known pulverization issue in alloy-type anodes.[1] The 2nd part of the talk will detail the impact of the crystalline-to-amorphous transformation on the rate capabilities of batteries. Here, I will present our nanoporous Sb/Na system, which transforms from crystalline Na3Sb to crystalline Sb, going through an amorphous intermediate. It will be shown using a combination of WAXS, electrochemical characterization, and computational study based on ab initio grand canonical (aiGCMC) simulations that the amorphous intermediate phase favors high rate Na storage in Sb.[2] [1] Wang, L., Welborn, S. S., Kumar, H., Li, M., Wang, Z., Shenoy, V. B., Detsi, E.: High‐Rate and Long Cycle‐Life Alloy‐Type Magnesium‐Ion Battery Anode Enabled Through (De)magnesiation‐Induced Near‐Room‐Temperature Solid–Liquid Phase Transformation. Adv. Energy Mater. 2019, 1902086. https://doi.org/10.1002/aenm.201902086 [2] M. Li, T. Qiu, S. S. Welborn, A. Foucher, B. Lesel, E. Stach, A. M. Rappe, E. Detsi: Understanding the Fast Kinetics of Sodium Storage in Antimony (unpublished)

In this work we use in situ electrochemical dilatometry techniques to demonstrate the existence of two distinct dimensional change mechanisms in lithium-sulfur cathodes during cycling, namely a reversible dimensional change occurring due to the difference in density between pure sulfur and lithiated sulfur compounds, and an irreversible shrinkage associated with polysulfide dissolution into the electrolyte. Our results contribute to elucidate the failure mechanism of lithium-sulfur cathodes, and the new insight can be used to improve the cycle-life of lithium-sulfur batteries. Indeed, while the reversible dimensional changes are fundamentally unavoidable, the irreversible dimensional changes can be mitigated by preventing the loss of active materials during cycling, which should obviously improve the battery cycle-life.

A novel phosphorus-containing polyhedral oligomeric silsesquioxane functionized graphene oxide(P-POSS-GO) were achieved and the resultant functionized GO combined with 4 wt% P-POSS were incorporated into bismaleimide resin to prepare flame-retardant P-POSS-GO/P-POSS/DBMI composite. Fourier-transform infrared spectra, transmission electron spectroscopy and X-ray diffraction were employed to examine the efficiency of surface functionalization of GO. The composite containing P-POSS and modified GO exhibited excellent flame-retardant property and better thermal stability as well as high mechanical property. With the incorporation of 0.6 wt% P-POSS-GO and 4 wt% P-POSS to DBMI, satisfied flame retardant grade V-0 and LOI as high as 39.4 were obtained. The increase of degradation activation energy could be internal reason for the improvement of flame retardancy. Besides, P-POSS-GO can facilitate the growth of oxygen insulation and heat insulation char layer, which could be outer reason for the improvement of flame retardancy.

Xiangshan Culture is a part of Lingnan Culture and a product of the combination of Chinese and Western Culture. And its abundant connotation is still of great research and development value for us. However, the existing research on Xiangshan Culture and the way of protection is far beyond satisfaction, and moreover, the way of inheritance lacks innovation. Therefore, to carry on a technical innovation on Xiangshan Culture, we use the modern information technical means — Knowledge Graph to sort out the traditional cultural knowledge, combine the Semantic Web technology, Named Graph, to build the Space-time Evolution Model, and set it up as a visual client software of Xiangshan Culture Knowledge Graph. Additionally, using the Knowledge Graph and the Space-time Evolution Model in the field of culture, is not only an innovative attempt in the field of culture and information technology, but also a brand new opportunity for Xiangshan area to show itself.

Recently, sodium-ion batteries (SIB) have been considered a promising alternative to lithium-ion batteries due to the abundance of sodium resources (sodium is the Earth’s 6th most abundant element, while lithium is 33rd) and its low extraction costs. Among various cathode candidates, the layered oxides NaTMO2 (TM=3d transition metal elements and their mixture) can accommodate sodium ions through intercalation mechanism, but suffer from major limitations including poor rate capability and short cycle-life. We have developed a novel bulk Na2/3[Ni1/3Mn2/3]O2 structure containing inclusions, which exhibits an unprecedented rate capability with roughly 50 % capacity retention at 50 C, and a remarkable long-term cycling stability with 95% capacity retention after 1000 cycles at 5 C. During this talk, I will present our new results and elucidate the mechanism through which the cycling performance of the novel materials system is enhanced. References Ruiz, M. Cochrane, M. Li, Y. Yan, K. Ma, J. Fu, Z. Wang, SH. Tolbert, VB. Shenoy, E. Detsi, Adv. Energy. Mater., 8 (2018) 1801781. Li, Z. Wang, J. Fu, K. Ma, E. Detsi, Scripta Materialia, 164 (2019) 52-56.

This paper presents an iterative learning controller for a flexible manipulator with uncertain parameters and unknown repetitive disturbance. The flexible manipulator is under-actuated with the assumption that only the rotation is controlled. Based on two sliding variables defined on the actuated and unactuated channels, the controller is designed with the compensation of the repetitive disturbance to drive the manipulator to track a time-varying trajectory. Theoretical proof and experimental studies are conducted to verify the effectiveness of the proposed controller.