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In order to obtain Al–Al2O3–ZrO2composite refractories with excellent oxidation resistance, erosion resistance and thermal shock stability, metallic aluminium and fused Al2O3–ZrO2were used as the raw materials, while phenolic resin was used as the binding agent. The microstructure was characterised by means of X-ray diffraction and scanning electron microscopy tests. Based on the reaction between zirconia and metallic aluminium under N2flowing at 1300 °C, the reaction mechanism of zirconia and metallic aluminium in-situ reaction at 1300 °C to generate (Al2OC)x(AlN)1−xsolid solution, zirconium nitride, and aluminium–zirconium alloy was revealed, and a model for the evolution of the phases in the aluminium-added Al–Al2O3–ZrO2specimen was constructed to realise the Al–Al2O3–ZrO2composite refractories phase controlling. Based on the good corrosion resistance of ZrO2to CaO and the excellent results of the in-situ reaction of metallic aluminium to generate a large number of non-oxide reinforcing phases capable of replacing elemental C, this work is of great significance for the study of refractory in erosion-heavy environments, such as calcium-treated steel.

Although impedance-based method has been proposed to effectively analyze interaction stability, the existing all-in-one impedance model-based method might encounter difficulty in identifying the physical significance of potential instability factors in the electric vehicle charging station and in solving the analytical solution of stabilization method aimed at entirely mitigating the voltage low-frequency oscillation (LFO) of each bandwidth due to its modeling complexity and high-order property. To address this issue, an analytical loop-correction stabilization method is designed based on the multi-timescale reduced-order impedance model to improve the dynamics of each bandwidth. Initially, the reduced-order expression of multi-timescale impedance model are presented by fitting the bode curve of closed voltage- and inertia-loop gain (Gvcl(s) and Gvir(s)). Subsequently, the analytical solution of loop-correction stabilization method can be designed and then performed to advance the phase and/or amplitude response of Gvcl(s) and Gvir(s). The negative damping within droop- and voltage-loop bandwidths is partly eliminated or completely offset, the LFO amplitude is suppressed and the LFO duration is shortened obviously due to the system stability enhancement and dynamic improvement. The voltage LFO of each timescale can be mitigated individually by the loop correction within each bandwidth. The bode-diagram-based solving process of this analytical loop-correction stabilization method is highly compatible for practical engineering applications. Finally, the effectiveness of proposed analytical loop-correction stabilization method is validated by physical experiment.

While improving the lithium metal (Li) Coulombic efficiency has been a focus for electrolyte design, the performance under high current densities is less studied yet highly relevant for practical applications. Here, we evaluate the charge-rate-dependent cycling stability using three types of weakly solvating fluoroether electrolytes. Although good cycle life was achieved in all three electrolytes under low current densities, they all exhibited a soft shorting behavior above various threshold current densities (between 2 and 5.2 mA cm–2). We attributed the current-dependent electrode morphology to both Li growth and residual solid electrolyte interface (rSEI) growth processes. In early cycles, Li morphology guided the formation of rSEI structures. In later cycles, the rSEI structure partially impacted Li growth. Under low current densities, the rSEI was inhomogeneous with large voids for subsequent bulky lithium growth. Under high current densities, the rSEI became more dense, which aggravated the high-surface/volume-ratio Li growth through and on the top of the rSEI. Among the three weakly solvating fluoroether electrolytes, the ones with lower ionic conductivity were observed to short within fewer cycles and at lower charge current densities. Our work suggests that fast ion transport in electrolytes may be a desirable feature for the stable operation at >1C charging in high-energy-density lithium metal batteries.

Lightning current is a fundamental parameter in lightning research. Previously, Rogowski coils and low-resistance shunts were used to measure lightning current down to a few amperes. Higher value resistors were also used to measure corona discharge current at subampere level, but they were unable to record the increasing current of the lightning leader. As a result, the transition from a corona discharge to a lightning leader process has not been well-addressed. To address this issue, we designed a shock-tolerant multi-range low-noise analog front end (AFE) for recording lightning current in the range from milliamperes to hundreds of kiloamperes. Large geometry D-MOSFETs were used instead of current limiting resistors to achieve a noise contribution of less than $0.4 \text {nV/}\sqrt {\text {Hz}} $ with a protection voltage of up to 100 V, and a noise density of $1.0 \text {nV/}\sqrt {\text {Hz}} $ for the AFE was finally achieved. With the system on a tall tower via a 0.25- $\text{m}\Omega $ shunt, corona current pulses of around 50 mA were identified using digital signal processing, while it is also able to withstand current pulses of over 220 kA.

Taking actual engineering as a case study, this article provides a novel scheme of applying the inductive power filtering method (IPFM) to resolve the harmonic resonance issues in large-scale photovoltaic (PV) plant. By using IPFM's special structure and dual zero-impedance design, the impedance network of large-scale PV plant is reshaped while the performance of power filters is improved, so that the harmonic resonance due to the interaction between the inverters and the power grid is suppressed. First, the topology and components of the IPFM-based large-scale PV plant are introduced. The three-phase mathematical model in harmonic domain is then established. Based on the deduced transfer matrix, the simplified circuit of the studied large-scale PV plant is obtained. Moreover, the IPFM's resonance damping mechanisms on resonant frequency shift and harmonic amplification mitigation are analyzed. Both simulation and engineering tests verify the feasibility of the proposal.

Henoch–Schönlein purpura (HSP) is a typical cutaneous immune skin disease, usually diagnosed by invasive biopsy. In this study, we develop a noninvasive optical method by combining in vivo optical clearing, confocal microscopy and immune-staining together to present the real-time in vivo dynamics of blood vessels, IgA molecules, and T cells in a HSP rat model. The small vessels in the skin are found with acute damage and then hyperplasia, which enhances deposition of IgA complexes in blood vessels. The migrating T cells in blood vessels in HSP regions can be detected by setting fast line scanning in this method. Our method provides in vivo vascular, cellular, and molecular dynamics during HSP development and is thus of great potential in research and diagnosis of HSP and other skin diseases.

In only a few decades, lithium-ion batteries have revolutionized technologies, enabling the proliferation of portable devices and electric vehicles1, with substantial benefits for society. However, the rapid growth in technology has highlighted the ethical and environmental challenges of mining lithium, cobalt and other mineral ore resources, and the issues associated with the safe usage and non-hazardous disposal of batteries2. Only a small fraction of lithium-ion batteries are recycled, further exacerbating global material supply of strategic elements3–5. A potential alternative is to use organic-based redox-active materials6–8to develop rechargeable batteries that originate from ethically sourced, sustainable materials and enable on-demand deconstruction and reconstruction. Making such batteries is challenging because the active materials must be stable during operation but degradable at end of life. Further, the degradation products should be either environmentally benign or recyclable for reconstruction into a new battery. Here we demonstrate a metal-free, polypeptide-based battery, in which viologens and nitroxide radicals are incorporated as redox-active groups along polypeptide backbones to function as anode and cathode materials, respectively. These redox-active polypeptides perform as active materials that are stable during battery operation and subsequently degrade on demand in acidic conditions to generate amino acids, other building blocks and degradation products. Such a polypeptide-based battery is a first step to addressing the need for alternative chemistries for green and sustainable batteries in a future circular economy.

The growing demand for compact energy storage devices may be met through the use of thin-film microbatteries, which generally rely on charge storage in thin or conformal layers. A promising technique for creating thin-film electrodes is layer-by-layer (LbL) assembly, based on the alternating adsorption of oppositely charged species to a surface to form a nanostructured electrode. Thin-film energy storage devices must have a high energy density within a limited space, so new electrode structures, materials, and assembly methods are important. To this end, both two-dimensional MXenes and polyaniline nanofibers (PNFs) have shown promising energy storage properties. Here, we report on the LbL assembly of positively charged PNFs and negatively charged Ti3C2TxMXenes into hybrid electrodes for thin-film energy storage devices. The successful assembly is demonstrated in which MXenes and PNFs are deposited in films of 49 nm/layer pair thickness. The resulting composition was 77 wt % PNFs and 23 wt % MXenes. The charge storage process was deconvoluted into faradaic/non-faradaic contributions and separated into contributions from PNFs and MXenes. A sandwich cell showed a maximum areal capacity, energy, and power of 17.6 μA h cm–2, 22.1 μW h cm–2, and 1.5 mW cm–2, respectively, for PNF/MXene multilayers of about 2 μm thickness. This work suggests the possibility of using LbL PNF/MXene thin films as electrode materials for thin-film energy storage devices used in next-generation small electronics.

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Organic radical polymers for batteries represent some of the fastest-charging redox active materials available. Electron transport and charge storage must be accompanied by ion transport and doping for charge neutrality, but the nature of this process in organic radical polymers is not well understood. This is difficult to intuitively predict because the pendant radical group distinguishes organic radical polymers from conjugated, charged or polar polymers. Here we show for the first time a quantitative view of in situ ion transport and doping in organic radical polymers during the redox process. Two modes dominate: doping by lithium ion expulsion and doping by anion uptake. The dominance of one mode over the other is controlled by anion type, electrolyte concentration and timescale. These results apply in any scenario in which electrolyte is in contact with a non-conjugated redox active polymer and present a means of quantifying doping effects.

The relationship between anemia and the outcome of patients with cirrhosis is not completely clear. Therefore, we performed this large-scale epidemiological study to investigate the prevalence and severity of anemia in patients with cirrhosis and acute decompensation or liver injury and how anemia impacts short-term and long-term outcomes.

The design and electrochemical synthesis of a conjugated radical polymer (CRP), poly(dithieno[3,2-b:2′,3′-d]pyrrole) bearing pendant nitroxide radicals, is reported. Conjugated radical polymers potentially offer simultaneous conductivity and redox activity in the context of organic energy storage. One challenge is understanding the internal electron transfer that occurs in CRPs, which affects the electrochemical energy storage properties. The CRP here is purposefully designed to examine the case of when the conjugated backbone’s redox potential is less than that of the organic radical group. Cyclic voltammetry on the as-prepared CRP exhibits two well-resolved redox peaks at Epa1= 3.15 V and Epa2= 3.61 V vs Li/Li+, corresponding to the redox activities of the (dithieno[3,2-b:2′,3′-d]pyrrole) (DTP) backbone and nitroxide radical, respectively. Galvanostatic charge/discharge studies also reveal a two-step charge/discharge process. The lower oxidation potential of DTP contributes to a conductive pathway during the charge/discharge process. An internal electron transfer process occurs during the decay of the open circuit potential, as the final potential stabilizes around 3 V. This strategy emphasizes the effects on energy storage when the redox active polymer contains two moieties that are redox active at different potentials, thus impacting future CRP design.

Bottle-aging improves the overall aroma of wine and different pH fermentation conditions can alter the evolution pattern of volatiles in wine during bottle-aging. In this study, the evolution of volatiles and aromas was investigated in different pH fermented bog bilberry syrup wines during a 6-month bottle-aging. Results showed that a total of 93 volatile compounds were found in bog bilberry syrup wine after fermentation. During bottle-aging, these volatiles exhibited 8 evolution patterns, and pH adjustment affected the evolution of esters, higher alcohols and acids. Eleven volatiles contributed their flavor scents to bog bilberry syrup wine overall aroma. Fruity, fatty and solvent scents were the major aromas, and pH adjustment induced an alteration on the aroma attributes during bottle-aging. Principal component analysis indicated that bottle-aging process segregated the sensory similarity of bog bilberry syrup wines through altering their aroma attributes. Low pH wine was separated from middle and high pH wines after 6 months of bottle-aging due to its high level of solvent and balsamic aromas. This indicated that pH adjustment resulted in a pattern difference on the evolution of volatiles during bottle-aging, which altered aroma profile of bog bilberry syrup wine.

This study compared the nutritional quality and sensory attributes of wine made from dried Gouqi berries that were mature (NDG), mildly over‐matured (MDG) and severely over‐matured (SDG). Whilst these wines had the similar physicochemical properties, the MDG wine possessed higher polysaccharide levels, whereas the highest total flavonoids were found in the NDG wine. A slight difference in the amino acid composition was observed in these wines, whereas they exhibited the same biogenic amines composition. The MDG and SDG wines exhibited weaker fruity, floral and caramel aromas compared with the NDG wine. However, these wines showed similar chemical and fatty aromas. Sensory evaluation revealed that these wines could be distinguished by panelists, and the NDG wine was preferred by most tasters, followed by the MDG and SDG wines. These results suggest that the Gouqi wine made from mature berries exhibits the best nutritional and organoleptic quality. However, the over‐matured and severely over‐matured berries could also be useful for Gouqi berry wine production but with different nutritional and sensory properties. Copyright © 2017 The Institute of Brewing & Distilling

The large-scale integration of wind power with intermittent characteristics into grids brings a challenge to the power system. Installation of the battery storage energy system (BESS) in a wind farm (WF) can effectively smooth wind power fluctuation. However, the BESS units may face the problem of over-charge/over-discharge if the power dispatch strategy for multiple units of BESS is improper, which results in lifetime degradation. In this paper, a dual-layer cooperative control strategy of multiple BESS units is proposed. In the first layer, the time-varying characteristics of wind power are introduced to define a power fluctuation coefficient. The coefficient can adjust the time constant of the first-order low pass filter (FLF) to avoid the deep energy utilization of BESS and decrease the over-charge/over-discharge possibility. To facilitate more power output for units with high SOC and absorb more energy for units with low SOC, the second layer calculates a SOC distribution factor by a function of the SOC of each unit to allocate the power command. The two layers of control operate cooperatively to reduce the SOC variation and unbalance degrees, thus the over-charge/over-discharge can be avoided, which is good for prolonging the lifetime of BESS with multiple units. Taking an actual WF in the Hunan province of China as the research object, the effectiveness of the proposed strategy is verified by the co-simulation of DIgSILENT/PowerFactory and Matlab/Simulink.

Electrochemically formed passive film on titanium in 1.0 M H2SO4solution and its thickness, composition, chemical state, and local fine structure are examined by Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and X-ray absorption fine structure. AES analysis reveals that the thickness and composition of oxide film are proportional to the reciprocal of current density in potentiodynamic polarization. XPS depth profiles of the chemical states of titanium exhibit the coexistence of various valences cations in the surface. Quantitative X-ray absorption near edge structure analysis of the local electronic structure of the topmost surface (∼5.0 nm) shows that the ratio of [TiO2]/[Ti2O3] is consistent with that of passivation/dissolution of electrochemical activity. Theoretical calculation and analysis of extended X-ray absorption fine structure spectra at Ti K-edge indicate that both the structures of passivation and dissolution are distorted caused by the appearance of two different sites of Ti–O and Ti–Ti. And the bound water in the topmost surface plays a vital role in structural disorder confirmed by XPS. Overall, the increase of average Ti–O coordination causes the electrochemical passivation, and the dissolution is due to the decrease of average Ti–Ti coordination. The structural variations of passivation in coordination number and interatomic distance are in good agreement with the prediction of point defect model.

Human immunodeficiency virus type 1 (HIV-1)-specific cytotoxic T lymphocytes (CTL) responses provide an important defense in controlling HIV-1 replication, but they fail to control the progression of AIDS in advanced HIV-1 infection. To uncover the situation of these responses in patients with advanced HIV-1 infection, we assessed HIV-1- specific CTL responses in 20 individuals with advanced HIV-1 infection using 407 overlapping peptides spanning all expressed HIV-1 proteins using a gamma interferon-enzyme-linked immunospot (ELISpot) assay. In comparison to 20 individuals with moderately advanced HIV-1 infection, HIV-1-specific CTL responses were significantly decreased (P0.044) and less peptides could be recognized (P0.05) in advanced HIV-1 infection. Weakening of Env-gp120 and Gag-specific CTL responses contributed importantly to the decrease of CTL magnitude (P0.042 and 0.078, respectively), while Env-gp41-specific CTL responses were relatively stronger during the end-stage of HIV-1 infection (P<0.001). Nef and Env-gp41 represented the most frequently targeted HIV-1 proteins in advanced HIV-1 infection. The entropy scores of peptides targeted in two groups were not significantly different. Only the breadth and magnitude of Envgp41- specific CTL responses were positively correlated with viral loads in advanced HIV-1 infection (P0.005 and 0.001, respectively). These findings suggest that progressive HIV-1 infection is associated with a weakening of Env-gp120- and Gag-specific CTL responses, and a simultaneous expansion of Env-gp41-specific CTL which is likely driven by high level viral replication.

To determine the degree of HIV-1-specific cytotoxic-T-lymphocyte (CTL) cross-responses to the clade B and C consensus sequences at the single peptide level. We assessed CTL responses in 46 HIV-1 clade B chronically infected individuals using an interferon-γ Elispot assay with a total of 826 overlapping peptides spanning HIV-1clade B and C consensus sequences. In general, 583 peptides were recognized by HIV-1-specific T cells in the study subjects (292 clade B, 291 clade C respectively), of which 204 peptides in both clades were recognized simultaneously. The HIV-1-specific CTL responses to both clade peptides contributed 54.23% (954/1759) to the total responses. No significant difference was observed between the overall magnitude or frequency of CTL responses to clade B proteins and those to clade C proteins. According to the profiles of CTL magnitude and CTL frequency, the top 44 and 35 synthetic peptides were identified as immunodominant regions in the clade B and C consensus sequences respectively and 27 corresponding peptides in two immunodominant regions were cross-reactive. These peptides with cross-reactivity had a significantly higher ability to elicit CTL responses (P &lt; 0.01) and preferentially had a trend of lower entropy and higher inter-clade homology. A wide degree of cross-clade reactivity of HIV-1-specific T cells exist in clade B and clade C variants. Most of immunodominant peptides with cross-reactivity are vigorous to elicit CTL responses and preferentially be conservative. This result may make future HIV-1 vaccines including multiple copies of CTL epitopes in these immunodominant peptides effective for this population.

To fully define HLA-A11- restricted HIV-1- specific cytotoxic T-lymphocyte epitopes in China, a method combining the enzyme-linked immunospot (ELISPOT) assay with intracellular gamma interferon staining (ICS) of peripheral blood mononuclear cells (PBMC) was used to map the optimal epitopes targeted by ELISPOT and then to define the HLA restriction of epitopes by ICS. A novel HLA-A11-restricted CTL epitope and five other published HLA-A11-restricted epitopes previously identified by reverse immunogenetics or other methods were defined. The approach of integrating ELISPOT with ICS is both convenient and useful for the characterization of CTL responses to HIV-1 infection; this method is practical for defining novel epitopes and facilitates in developing new strategies for future vaccine design in China and other Asian countries.

CD4+ T cell counts and CD4+:CD8+ T cell ratios represent key determinants of HIV disease progression and infectivity. However, the relationship between the HIV-1-specific cytotoxic T lymphocyte (CTL) response and these determinants has not been elucidated for all HIV-1B and HIV-1C proteins. In the present study, virusspecific T cell responses to HIV-1B and HIV-1C proteins were analyzed with interferon gamma (IFN-γ) enzyme- linked immunospot (ELISpot) assays using synthetic overlapping peptides corresponding to naturally occurring HIV-1B and HIV-1C consensus sequences. For Gag/Gag p24/Gag p17, a correlation between T cell responses and CD4+ T cell count in HIV-1 clade B and clade C was seen: elevated T cell response resulted in higher CD4+ T cell production. A statistically significant correlation between the Pol-specific T cell response and CD4+ T cell counts was also found in HIV-1 subtype C. For all HIV-1B and HIV-1C proteins, a correlation between the HIV-1-specific T cell response and CD4+:CD8+ T cell ratios was found for Tat and Pol proteins. CD4+ T cell counts in patients with Tat and/or Rev T cell response were higher than in patients without Tat and/or Rev T cell response. We suggest that this correlation within HIV-1B and HIV-1C Gag p24/Gag p17 responses makes the Gag p24/Gag p17 region a potential vaccine candidate and that HIV-1-specific CTL epitopes toward Pol are important in controlling HIV-1 infection; we emphasize that future vaccination strategies should include these early antigens, Tat and Rev.

As the demand for wearable electronic devices increases, interest in small, light, and deformable energy storage devices follows suit. Among these devices, wire-shaped supercapacitors (WSCs) are considered key components of wearable technology due to their geometric similarity to woven fiber. One potential method for creating WSC devices is the layer-by-layer (LbL) assembly technique, which is a “bottom-up” method for electrode fabrication. WSCs require conformal and adhesive coatings of the functional material to the wire-shaped substrate, which is difficult to obtain with other processing techniques such as vacuum filtration or spray-coating. However, the LbL assembly technique produces conformal and robust coatings that can be deposited onto a variety of substrates and shapes, including wires. In this study, we report WSCs made using the LbL assembly of alternating layers of positively charged reduced graphene oxide functionalized with poly(diallyldimethylammonium chloride) and negatively charged Ti3C2TxMXene nanosheets conformally deposited on activated carbon yarns. In this construct, the added LbL film enhances capacitance, energy density, and power density by 240, 227, and 109%, respectively, relative to the uncoated activated carbon yarn, yielding high specific and volumetric capacitances (237 F g–1, 2193 F cm–3). In addition, the WSC possesses good mechanical stability, retaining 90% of its initial capacity after 200 bending cycles. This study demonstrates that LbL coatings on carbon yarns are promising as linear energy storage devices for fibrous electronics.

Two initial upward positive leaders (UPLs) in upward negative flashes initiated from a 356‐m‐tall tower were observed with a high‐speed camera, an electric field sensor, and a magnetic field sensor. Although the waveforms of electric fields measured were saturated, both camera images and magnetic fields showed that the two UPLs had obvious stepwise characteristics in their upward moving stage. The magnetic fields associated with the UPLs were characterized by a series of fast‐changing bipolar impulses superimposed on a slowly increasing continuous component as the leaders moved upward, which were well corresponding to the light intensity changes of their high‐speed camera images. The 2‐D step length and step extension speed of the two leaders were estimated in the range of 0.5–3 m and 1.1–9.4 × 105m/s, respectively. The radius of the leader luminous channel as a function of time and height was also estimated. The channel radius showed first a stable increasing trend in the leader upward moving stage and then 4–5 times of shrinking and expanding processes after the leader connected the cloud. The channel expanding and shrinking speeds were in the range of 2–9 × 104m/s. Particularly, the channel radius showed an obvious increasing trend with the increase of the height all the time, which was in the range of 2.8–3.5 m when around the tower tip and of 5.6–8.4 m when at 24 m high above the tower tip. Such a feature of the channel radius is in good agreement with the concept of leader corona sheath in literature. Two upward positive stepped leaders initiated from a tall tower were analyzed based on magnetic field and high‐speed camera measurementsThe leader step length and step extension speed were found in the range of 0.5–3 m and 105–106m/s, respectivelyThe leader channel had an expanding and shrinking feature and an increasing trend with height in the range of 2–10 m