Negative Hysteresis Research Articles

Reversible negative compressibility metamaterials inspired by Braess’s Paradox

Negative compressibility metamaterials have attracted significant attention due to their distinctive properties and promising applications. Negative compressibility has been interpreted in two ways. Regarding the negative compressibility induced by a uniaxial load, it can only occur abruptly when the load reaches a certain threshold. Hence, it can be termed as transient negative compressibility. However, fabrication and experiments of such metamaterials have rarely been reported. Herein, we demonstrate them. Inspired by Braess’s paradox, a novel mechanical model is proposed with reversible negative compressibility. It shows multiple types of force responses during a loading-unloading cycle, including transient negative compressibility and hysteresis. Phase diagrams are employed to visualize the relationship between force responses and system parameters. Besides, explicit expressions for the conditions and intensity of negative compressibility are obtained for design and optimization. The model replacement method inspired by compliant mechanism design is then introduced to derive specific unit cell structures, thus avoiding intuition-based approaches. Additive manufacturing technology is utilized to fabricate the prototypes, and negative compressibility is validated via simulations and experiments. Furthermore, it is demonstrated that metamaterials with transient negative compressibility can be activated through electrical heating and can function as actuators, thereby possessing machine-like properties. The proposed mechanical metamaterial and the introduced design methodology have potentials to impact micro-electromechanical systems, force sensors, protective devices, and other applications.

Bending restoring force model of angle-steel reinforced concrete columns under combined torsion

To explore the restoring force model of an angle steel truss reinforced concrete column (ASRC) under the combined action of compression, bending, shear, and torsion, nine ASRC columns under a combined torsion environment were tested and analyzed. This study observed and summarized the failure mode characteristics of different component columns, distinguished different failure modes, and analyzed the hysteresis curve and energy dissipation capacity of component columns. Then, a trilinear skeleton curve model suitable for ASRC columns is adopted, and the calculation method of skeleton curves in different stages under the combined action of compression, bending, shear, and torsion is given. Finally, the ASRC hysteresis rule is simplified, and fitting produces the formulae for positive and negative hysteresis curve unloading stiffness. The restoring force model of the ASRC column under coupled torsion is established, and the test results validate the restoring force model. The results show that the established restoring force model can predict the hysteretic behavior of ASRC under combined torsion. This research can be used as a theoretical foundation as well as an experimental reference for the technical use of ASRC.

Generic dynamic molecular devices by quantitative non-steady-state proton/water-coupled electron transport kinetics

Dynamic molecular devices operating with time- and history-dependent performance raised new challenges for the fundamental study of microscopic non-steady-state charge transport as well as functionalities that are not achievable by steady-state devices. In this study, we reported a generic dynamic mode of molecular devices by addressing the transient redox state of ubiquitous quinone molecules in the junction by proton/water transfer. The diffusion limited slow proton/water transfer-modulated fast electron transport, leading to a non-steady-state transport process, as manifested by the negative differential resistance, dynamic hysteresis, and memory-like behavior. A quantitative paradigm for the study of the non-steady-state charge transport kinetics was further developed by combining the theoretical model and transient state characterization, and the principle of the dynamic device can be revealed by the numerical simulator. On applying pulse stimulation, the dynamic device emulated the neuron synaptic response with frequency-dependent depression and facilitation, implying a great potential for future nonlinear and brain-inspired devices.

Detection and Prediction of the Early Thermal Runaway and Control of the Li-Ion Battery by the Embedded Temperature Sensor Array.

Sorts of Li-ion batteries (LIB) have been becoming important energy supply and storage devices. As a long-standing obstacle, safety issues are limiting the large-scale adoption of high-energy-density batteries. Strategies covering materials, cell, and package processing have been paid much attention to. Here, we report a flexible sensor array with fast and reversible temperature switching that can be incorporated inside batteries to prevent thermal runaway. This flexible sensor array consists of PTCR ceramic sensors combined with printed PI sheets for electrodes and circuits. Compared to room temperature, the resistance of the sensors soars nonlinearly by more than three orders of magnitude at around 67 °C with a 1 °C/s rate. This temperature aligns with the decomposition temperature of SEI. Subsequently, the resistance returns to normal at room temperature, demonstrating a negative thermal hysteresis effect. This characteristic proves advantageous for the battery, as it enables a lower-temperature restart after an initial warming phase. The batteries with an embedded sensor array could resume their normal function without performance compromise or detrimental thermal runaway.

Three-dimensional ori-kirigami metamaterials with multistability.

Ori-kirigami structures offer a good avenue for designing mechanical metamaterials due to their unique advantage of being independent of material properties and scale limitations. Recently, the scientific community has been greatly interested in exploiting the complex energy landscape of ori-kirigami structures to construct multistable systems and play their valuable role in different applications. Here, we present three-dimensional ori-kirigami structures based on generalized waterbomb units, a cylindrical ori-kirigami structure based on waterbomb units, and a conical ori-kirigami structure based on trapezoidal waterbomb units. We investigate the inherent relationships between the unique kinematics and mechanical properties of these three-dimensional ori-kirigami structures and explore their potential usage as mechanical metamaterials that exhibit negative stiffness, snap-through, hysteresis effects, and multistability. What makes the structures even more attractive is their massive folding stroke, where the conical ori-kirigami structure can obtain a huge folding stroke of more than twice its initial height through penetration of its upper and lower boundaries. This study forms the foundation for designing and constructing three-dimensional ori-kirigami metamaterials based on generalized waterbomb units for various engineering applications.

The First-Water-Layer Evolution at the Graphene/Water Interface under Different Electro-Modulated Hydrophilic Conditions Observed by Suspended/Supported Field-Effect-Device Architectures.

Interfacial water molecules affect carrier transportation within graphene and related applications. Without proper tools, however, most of the previous works focus on simulation modeling rather than experimental validation. To overcome this obstacle, a series of graphene field-effect transistors (GFETs) with suspended (substrate-free, SF) and supported (oxide-supported, OS) configurations are developed to investigate the graphene-water interface under different hydrophilic conditions. With deionized water environments, in our experiments, the electrical transportation behaviors of the graphene mainly originate from the evolution of the interfacial water-molecule arrangement. Also, these current-voltage behaviors can be used to elucidate the first-water layer at the graphene-water interface. For SF-GFET, our experimental results show positive hysteresis in electrical transportation. These imply highly ordered interfacial water molecules with a separated-ionic distributed structure. For OS-GFET, on the contrary, the negative hysteresis shows the formation of the hydrogen-bond interaction between the interfacial water layer and the SiO2 substrate under the graphene. This interaction further promotes current conduction through the graphene/water interface. In addition, the net current-voltage relationship also indicates the energy required to change the orientation of the first-layer water molecules during electro-potential change. Therefore, our work gives an insight into graphene-water interfacial evolution with field-effect modulation. Furthermore, this experimental architecture also paves the way for investigating 2D solid-liquid interfacial features.

Crack‐Free Monolayer Graphene Interlayer for Improving Perovskite Crystallinity and Energy Level Alignment in Efficient Inverted Perovskite Solar Cells

Inverted planar perovskite solar cells (PSCs) have intrigued great promise in negative hysteresis, simple fabrication process, and flexible substrate implementation, in which the shared hole transport materiel is NiOx. However, the low‐temperature solution processing of the NiOx film is usually accompanied by defect formation, which deteriorates the perovskite quality and device performance. Meanwhile, the energy‐level offset between the NiOx and perovskite films is relatively large, limiting the interfacial charge transport. To suppress those setbacks, a defect‐free monolayer graphene sheet is transferred onto the NiOx film surface as a template for van der Waals epitaxial growth of perovskite films for the first time, leading to enhancing crystallinity with a large grain size of perovskite layer, 0.20 eV energy level offset drop, and accelerating charge transfer for the devices. Finally, the power conversion efficiency of 19.21% without hysteresis is achieved, exceeding 18.35% of the control device.

Microstructure and Corrosion Properties of Electrodeposited CoCrFeMnNi High Entropy Alloy Coatings

This study investigated the effect of potential change on the microstructure and corrosion properties of CoCrFeMnNi HEA coatings synthesized by the electrochemical deposition method. The films were precipitated in an electrolyte based on a DMF-CH3CN organic system comprising Co, Cr, Fe, Mn, and Ni cations. GIXRD pattern in all samples showed a single face-centered-cubic structure. SEM-EDS results show that the coating morphology and the elements value in alloy composition vary at different coating potentials. Coatings were uniform and crack-free surfaces. The results of the wettability test showed all coatings were super-hydrophilic. All the alloys exhibited similar passivation and negative hysteresis processes in the CPP test. However, the 5 V sample exhibited a lower Epit value than the 6 V, and none of the samples were sensitive to pitting corrosion. The CPP test result showed that the corrosion current density of the 5 V sample was 0.0525 μA/cm2, the minimum corrosion rate for the coated samples, and has improved the corrosion resistance of the substrate by about 44 times. The EIS test results showed the excellent performance of the coatings in enhancing the corrosion resistance compared to Cu substrate and similar alloy samples in a 3.5 wt% NaCl solution, as the protection efficiency was about 90%. These High entropy alloy coatings are suitable for engineering applications in which higher corrosion protection is needed.

Carbon hysteresis hypothesis as a new approach to emission behavior: A case of top five emitters

The purpose of the current study is to explain the unstoppable dramatic increases in emissions by proposing a new hypothesis as carbon hysteresis hypothesis. If the emissions have a path dependence or a unit root, a given shock to the emissions will make its equilibrium to a new level in long-run. In this case, the carbon hysteresis hypothesis will be valid. On the other hand, if the emission series is stationary, emissions will resist given shocks in long-run, hence there will be no hysteresis effect. Furthermore, this study reveals the direction of hysteresis. Accordingly, the positive hysteresis indicates continuous increase in emissions while the negative hysteresis indicates continuous decrease in emissions that means carbon reduction.This study achieves robust results by three different structural break panel unit root strategies. In doing so, the panel unit root tests are performed to test carbon hysteresis on the top-five emitting countries: China, India, Japan, Russian Federation and USA over the time period 1965–2020.The main conclusion is that the carbon hysteresis hypothesis is valid for these countries. Moreover, we estimated six different trend models for each regime of sample period for all countries to determine the direction of the hysteresis. In conclusion, this study proposes a new hypothesis to assist countries on their way to the reduction targets.

Unconventional VTC of subthreshold inverter with MFMIS negative capacitance transistor: An analytical modelling framework with implications for ultralow power logic design

The present reports an analytical modelling framework to provide insights into subthreshold logic design using metal-ferroelectric-metal–insulator-semiconductor (MFMIS) negative capacitance field effect transistor (NCFET). It is shown that the proposed model is effective in predicting supply voltage (V DD) dependent hysteresis as well as hysteresis-free voltage transfer characteristics (VTC) through the analytically obtained positive (hysteresis-free) and negative (hysteresis) values of gain (−dV O/dV IN) in NCFET based subthreshold inverter. The proposed subthreshold drain current model for NCFET has been extended to obtain closed-form analytical expressions of figures of merit of a subthreshold inverter such as nominal high and low output voltages, threshold logic voltage, and DC gain. The model while successfully capturing characteristics of MFMIS NCFETs is able to predict the occurrence of hysteresis in VTC due to negative differential resistance in the output characteristics of NCFET. Results show that an optimally designed MFMIS NCFET based inverter can achieve similar values of DC gain as exhibited by conventional MOSFET at ∼×(3–6) times lower supply voltages (V DD) along with an improvement in static and dynamic power dissipation. Results showcase an analytical modelling framework and its implications for reducing V DD for ultralow power subthreshold logic design with NCFETs.

A Gene Cluster with Positive and Negative Control Elements Monitor Bistability and Hysteresis of the Crippled Versus Normal Growth in the Fungus Podospora Anserina

A Gene Cluster with Positive and Negative Control Elements Monitor Bistability and Hysteresis of the Crippled Versus Normal Growth in the Fungus Podospora Anserina

Adsorption and desorption of Cu, Zn, Pb, and Cd on surface sediments from a shallow lake, North China

The processes of adsorption and desorption of heavy metal ions on sediments is of great significance for water quality conservation. To investigate the adsorption and release characteristics of heavy metals on sediments from shallow lakes, an isothermal adsorption and desorption experiment of Cu2+, Zn2+, Pb2+, and Cd2+ on sediments from Baiyun Lake was carried out. Our results showed that sediments demonstrated a strong capacity of absorbing these heavy metal ions in a sorption system. The maximum sorption capacity for heavy metals on sediments followed the order Pb2+> Cd2+> Cu2+> Zn2+. The followed order of the maximum buffer capacities for heavy metals was Pb2+ > Cu2+ > Zn2+ > Cd2+. The Langmuir isotherms model can better fit the adsorption of Cu2+, whereas the Freundlich isotherm model for the adsorption of Zn2+, Pb2+, and Cd2+. In the maximum initial concentration treatment, Pb exhibited the highest desorption amount, followed by Cu and Zn, whereas the lowest amount of Cd was observed. The exponential and quadratic functions could describe the relationships of adsorption and desorption. In the maximum initial concentration treatment, the adsorption rates of these four heavy metals followed the order Pb2+ > Cd2+> Cu2+> Zn2+, whereas the desorption rates followed an opposite order. The hysteresis index (HI) values for Zn was smaller than 1, whereas the HI values for Cu and Cd were slightly larger than 1, suggesting slightly negative hysteresis processes. However, the HI value of Pb was larger than 1, indicating that Pb2+ was easily desorbed from sediments.

Citric Acid as an Alternative to Sulfuric Acid for the Hard-Anodizing of AA6061

Hard-anodized is a widely used method in the aeronautical sector to improve aluminum alloys abrasion and corrosion resistance. Aim of this work was to characterize the mechanical properties and resistance hard-anodized aluminum 6061 in citric acid solution as a replacement sulfuric acid solution were investigated. Aluminum alloy 6061 was used as the base material to produce the hard anodizing; this process was carried out in a citric and sulfuric acid solution, applying current densities 3 and 4.5 A/cm2 and subsequently exposed to 3.5 wt. % NaCl solution. Microstructure and mechanical properties of the anodizing material were characterized by scanning electron microscopy (SEM) and Vickers microhardness (HV). Corrosion behavior of the hard-anodized material it was carried out with electrochemical techniques as cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS) respectively. Results obtained indicated that all samples anodized in citric acid solution showed negative hysteresis and lower corrosion current density (1 × 10−10 A/cm2), indicating generalized corrosion on the material surface. EIS results show that anodizing in citric acid solution and a current density of 4.5 A/dm2 provides better corrosion protection than a sulfuric acid solution.

Atrazine behavior in an agricultural soil: adsorption–desorption, leaching, and bioaugmentation with Arthrobacter sp. strain AAC22

PurposeTo evaluate atrazine behavior in an agricultural soil (adsorption–desorption, leaching) and the effects of bioaugmentation with the Arthrobacter sp. strain AAC22, as a soil remediating strategy.Material and methodsAn agricultural soil with a history of atrazine application was used. Equilibrium batch experiments allowed the investigation of the adsorption–desorption of atrazine at different soil depths, while the atrazine leaching potential was assessed using disturbed soil columns. Arthrobacter sp. strain AAC22 was selected for bioaugmentation, to remove atrazine in soil microcosms. Removal efficiency was determined by a bioassay with oat seeds.Results and discussionAdsorption and desorption isotherms of atrazine at different soil depths were well described by the Freundlich equation (R2 > 0.99 and R2 > 0.98, respectively). The Freundlich constant (Kf) and desorption coefficient (Kfd1–3) decreased and increased, respectively, as soil depth increased. The Kf and Kfd1–3 values were correlated positively to organic carbon (r = 0.97) and negatively to pH (r = − 0.93). In this soil, 70.2% of atrazine applied (2.5 kg ha−1) was recovered in the leachate and 7.6% remained in the soil column. The higher atrazine concentration leached can be explained by the negative hysteresis of adsorption–desorption in this soil. Bioaugmentation with AAC22 enhanced atrazine removal being nearly 70% after 2 days of treatment, and it was almost complete (> 99%) after 8 days. A bioassay demonstrated that bioaugmentation was successful and toxic by-products were not detected.ConclusionThe adsorption–desorption and leaching experiments demonstrated the high mobility of the atrazine in the study soil. The bioaugmentation using the AAC22 strain is an effective strategy for atrazine removal in polluted soils.

Origin of friction hysteresis on monolayer graphene

Load-dependent friction hysteresis is an intriguing phenomenon that occurs in many materials, where the friction measured during unloading is larger than that measured during loading for a given normal load. However, the mechanism underlying this behavior is still not well understood. In this work, temperature-controlled friction force microscopy was utilized to explore the origin of friction hysteresis on exfoliated monolayer graphene. The experimental observations show that environmental adsorbates from ambient air play an important role in the load dependence of friction. Specifically, the existence of environmental adsorbates between the tip and graphene surface gives rise to an enhanced tip-graphene adhesion force, which leads to a positive friction hysteresis where the friction force is larger during unloading than during loading. In contrast to positive friction hysteresis, a negative friction hysteresis where the friction force is smaller during unloading than during loading is observed through the removal of the environmental adsorbates upon in situ annealing. It is proposed that the measured friction hysteresis originates from the hysteresis in the contact area caused by environmental adsorbates between the tip and graphene. These findings provide a revised understanding of the friction hysteresis in monolayer graphene in terms of environmental adsorbates.

High potency of sequential therapy with only β-lactam antibiotics

Evolutionary adaptation is a major source of antibiotic resistance in bacterial pathogens. Evolution-informed therapy aims to constrain resistance by accounting for bacterial evolvability. Sequential treatments with antibiotics that target different bacterial processes were previously shown to limit adaptation through genetic resistance trade-offs and negative hysteresis. Treatment with homogeneous sets of antibiotics is generally viewed to be disadvantageous as it should rapidly lead to cross-resistance. We here challenged this assumption by determining the evolutionary response of Pseudomonas aeruginosa to experimental sequential treatments involving both heterogenous and homogeneous antibiotic sets. To our surprise, we found that fast switching between only β-lactam antibiotics resulted in increased extinction of bacterial populations. We demonstrate that extinction is favored by low rates of spontaneous resistance emergence and low levels of spontaneous cross-resistance among the antibiotics in sequence. The uncovered principles may help to guide the optimized use of available antibiotics in highly potent, evolution-informed treatment designs.

Sorption and desorption characteristics of sulfamethazine in three different soils before and after removal of organic matter

Organic matter (OM) is the most critical factor in controlling the sorption-desorption of SMZ in soil, however, few studies have explored the effects of OM removal on these important behaviors among different soils. Batch experiments were conducted to investigate the sorption and desorption characteristics of SMZ in three different soils: fluvo-aquic soil (FS), paddy soil (PS), and red soil (RS). The SMZ sorption in the evaluated soils was dominated by physisorption. The SMZ sorption capacities of FS and PS, which had a relatively higher OM content than RS, were higher than that of RS. The SMZ sorption in FS was dominated by linear partitioning. In contrast, the SMZ sorption in PS and RS was mainly nonlinear surface adsorption. After OM removal, the SMZ sorption capacity was significantly reduced in FS but increased in PS and RS. Furthermore, OM removal restrained the sorption intensity of SMZ in soils. Relatively higher OM and clay contents inhibited the SMZ desorption in FS and PS. The strong negative desorption hysteresis of SMZ in the three soils indicated that SMZ was able to move into the soil solution, thereby posing a risk to humans. Taken together, the findings of this study showed that OM indeed plays an important role during SMZ sorption-desorption in soil.

Van Der Waals Epitaxial Growth and Phase Transition of Layered FeSe2 Nanocrystals.

Layered iron chalcogenides (FeX, X = S, Se, Te) provide excellent platforms to study intertwined phase transitions, superconductivity, and magnetism. However, layered iron dichalcogenides (FeX2 , X = S, Se, Te) are rarely reported and their intrinsic properties are still unknown. Here, phase-pure layered iron diselenide (FeSe2 ) nanocrystals are epitaxially grown on mica by the sublimed-salt-assisted chemical vapor deposition method at atmospheric pressure. The layered atomic structure of FeSe2 is confirmed by X-ray diffraction and atomic-resolution scanning transmission electron microscopy. Electrical transport shows that the layered FeSe2 is a metal with high conductivity and a phase transition at ≈11 K. The phase transition manifests itself as a kink in the temperature-dependent resistivity, as well as anomalous magnetoresistance (MR) appearing around the phase-transition temperature. The MR changes from negative to positive, accompanied by large hysteresis near the phase-transition temperature upon cooling. The negative MR and hysteresis might originate from magnetic field suppression scattering of spin fluctuations and competition of magnetic interactions induced by the phase transition, respectively. Layered iron dichalcogenide will be potential candidate to explore novel quantum phenomena and other applications.

Persistence, mobility, and leaching risk of flumioxazin in four Chinese soils

Flumioxan was used to control annual broad-leaved and dicotyledonous weeds. Considering the limited information available, comprehensive investigation of persistence and mobility of flumioxazin in Chinese soil is very important. The degradation, adsorption-desorption, mobility, and leaching risk of flumioxazin in four Chinese soils were investigated under laboratory conditions. The degradation rates of flumioxazin, which correlated with soil moisture, microorganisms, organic matter and pH, were 8.2−50.6 days in the four soils under different conditions. Microorganisms influenced these rates greatly, with half-lives increasing 1.67−2.39-fold. Three possible metabolites were detected by ultrahigh-performance liquid chromatography with high-resolution mass spectrometry, and the metabolic pathways were cleavage of the imide and amide linkages and opening of the cyclic imide. The adsorption capacity of flumioxazin in soil was strongly positively correlated with the soil’s cation exchange capacity (CEC) and organic matter (OM) content, which had correlation coefficients > 0.83. Negative and positive desorption hysteresis effects were observed in Guizhou soil and the other three soils, respectively, which might be related to the different soil constitutions. The mobility was relatively weak in the four Chinese soils and negatively related to CEC and OM content, with correlation coefficients > 0.86. Moreover, the leaching risk of flumioxazin was uncertain for the underground water. The results indicated that flumioxazin was a low-risk herbicide and could be used to evaluate the environmental fate and risk of flumioxazin in soil.

Improvement of Wear, Pitting Corrosion Resistance and Repassivation Ability of Mg-Based Alloys Using High Pressure Cold Sprayed (HPCS) Commercially Pure-Titanium Coatings

In this study, a compact cold sprayed (CS) Ti coating was deposited on Mg alloy using a high pressure cold spray (HPCS) system. The wear and corrosion behavior of the CS Ti coating was compared with that of CS Al coating and bare Mg alloy. The Ti coating yielded lower wear rate compared to Al coating and Mg alloy. Electrochemical impedance spectroscopy (EIS) and cyclic potentiodynamic polarization (CPP) tests revealed that CS Ti coating can substantially reduce corrosion rate of AZ31B in chloride containing solutions compared to CS Al coating. Interestingly, Ti-coated Mg alloy demonstrated negative hysteresis loop, depicting repassivation of pits, in contrast to AZ31B and Al-coated AZ31B with positive hysteresis loops where corrosion potential (Ecorr) > repassivation potential (Erp); indicating irreversible growth of pits. AZ31B and Al-coated AZ31B were most susceptible to pitting corrosion, while Ti-coated Mg alloy indicated noticeable resistance to pitting in 3.5 wt % NaCl solution. In comparison to Al coating, Ti coating considerably separated the AZ31BMg alloy surface from the corrosive electrolyte during long term immersion test for 11 days.