Biaxial strain modulated electronic structures of layered two-dimensional MoSiGeN4 Rashba systems.

The two-dimensional (2D) MA2Z4 family has received extensive attention in manipulating its electronic structure and achieving intriguing physical properties. However, engineering the electronic properties remains a challenge. Herein, based on first-principles calculations, we systematically investigate the effect of biaxial strains on the electronic structure of 2D Rashba MoSiGeN4 (MSGN), and further explore how the interlayer interactions affect the Rashba spin splitting (RSS) in such strained layered MSGN systems. After applying biaxial strains, the band gap decreases monotonically with increasing tensile strains but increases when the compressive strains are applied. An indirect-direct-indirect band gap transition is induced by applying a moderate compressive strain (<5%) in the MSGN systems. Due to the symmetry breaking and moderate spin-orbit coupling (SOC), the monolayer MSGN possesses an isolated RSS near the Fermi level, which could be effectively regulated to the Lifshitz-type spin splitting (LSS) by biaxial strain. For instance, the LSS ← RSS → LSS transformation of the Fermi surface is presented in the monolayer and a more complex and changeable LSS ← RSS → LSS → RSS evolution is observed in bilayer and trilayer MSGN systems as the biaxial strain varies from -8% to 12%, which actually depends on the appearance, variation, and vanish of the Mexican hat band in the absence of SOC under different strains. The contribution of the Mo-dz2 orbital hybridized with the N-pz orbital in the highest valence band plays a dominant role in band evolution under biaxial strains, where the RSS → LSS evolution corresponds to the decreased Mo-dz2 orbital contribution. Our study highlights the biaxial strain controllable RSS, in particular the introduction and even the evolution of LSS near the Fermi surface, which makes the strained MSGN systems promising candidates for future applications in spintronic devices.

Alloying enhanced negative Poisson's ratio in two-dimensional aluminum gallium nitride (AlxGa1-xN).

The negative Poisson's ratio (NPR) effect usually endows materials with promising ductility and shear resistance, facilitating a wider range of applications. It has been generally acknowledged that alloys show strong advantages in manipulating material properties. Thus, a thought-provoking question arises: how does alloying affect the NPR? In this paper, based on first-principles calculations, we systematically study the NPR in two-dimensional (2D) GaN and AlN, and their alloy of AlxGa1-xN. It is intriguing to find that the NPR in AlxGa1-xN is significantly enhanced compared to the parent materials of GaN and AlN. The underlying mechanism mainly originates from a counter-intuitive increase of the bond angle θ. We further study the microscopic origin of the anomalies by electron orbital analysis as well as electron localization functions. It is revealed that the distribution and movement of electrons change with the applied strain, providing a fundamental view on the effect of strain on lattice parameters and the NPR. The physical origin as revealed in this study deepens the understanding of the NPR and shed light on the future design of modern nanoscale electromechanical devices with fantastic functions based on the auxetic nanomaterials and nanostructures.

Interfacial Evolution on Co-based Oxygen Evolution Reaction Electrocatalysts Probed by Using In Situ Surface-Enhanced Raman Spectroscopy.

Disclosing the roles of reactive sites at catalytic interfaces is of paramount importance for understanding the reaction mechanism. However, due to the difficulties in the detection of reaction intermediates in the complex heterophase reaction system, disentangling the highly convolved roles of different surface atoms remains challenging. Herein, we used CoOx as a model catalyst to study the synergy of CoTd2+ and CoOh3+ active sites in the electrocatalytic oxygen evolution reaction (OER). The formation and evolution of reaction intermediates on the catalyst surface during the OER process were investigated by in situ surface-enhanced Raman spectroscopy (SERS). According to the SERS results in ion-substitution experiments, CoOh3+ is the catalytic site for the conversion of OH- to O-O- intermediate species (1140-1180 cm-1). CoOOH (503 cm-1) and CoO2 (560 cm-1) active centers generated during the OER, at the original CoTd2+ sites of CoOx, eventually serve as the O2 release sites (conversion of O-O- intermediate to O2). The mechanism was further confirmed on Co2+-Co3+ layered double hydroxides (LDHs), where an optimal ratio of 1:1.2 (Co2+/Co3+) is required to balance O-O- generation and O2 release. This work highlights the synergistic role of metal atoms at different valence statuses in water oxidation and sheds light on surface component engineering for the rational design of high-performance heterogeneous catalysts.

Tuning the Electronic Properties of Platinum in Hybrid-Nanoparticle Assemblies for use in Hydrogen Evolution Reaction.

Platinum is the best electrocatalyst for the hydrogen evolution reaction (HER). Here, we demonstrate that by contact electrification of Pt nanoparticle satellites on a gold or silver core, the Fermi level of Pt can be tuned. The electronic properties of Pt in such hybrid nanocatalysts were experimentally characterized by X-ray photoelectron spectroscopy (XPS) and surface-enhanced Raman scattering (SERS) with the probe molecule 2,6-dimethyl phenyl isocyanide (2,6-DMPI). Our experimental findings are corroborated by a hybridization model and density functional theory (DFT) calculations. Finally, we demonstrate that tuning of the Fermi level of Pt results in reduced or increased overpotentials in water splitting.

Anisotropic thermal and electrical transport properties induced high thermoelectric performance in an Ir2Cl2O2 monolayer.

In recent years, the energy crisis and global warming have been urgent problems that need to be solved. As is known, thermoelectric (TE) materials can transfer heat energy to electrical energy without air pollution. High-throughput calculations as a novel approach are adopted by screening promising TE materials. In this paper, we use first-principles calculations combined with the semiclassical Boltzmann transport theory to estimate the TE performance of monolayer Ir2Cl2O2 according to the prediction that Ir2Cl2O2 has potential as a good TE material via high-throughput calculations. The low thermal conductivities of 1.73 and 4.68 W mK-1 of Ir2Cl2O2 along the x- and y-axes are calculated, respectively, which exhibits the strong anisotropy caused by the difference in group velocities of low-frequency phonon modes. Then, the electronic transport properties are explored, and the figure of merit ZT is eventually obtained. The maximum ZT value reaches 2.85 (0.40) along the x-axis (y-axis) at 700 K, revealing that the TE properties of the Ir2Cl2O2 monolayer are highly anisotropic. This work reveals that the anisotropic layer Ir2Cl2O2 exhibits high TE performance, which confirms that it is feasible to screen excellent TE materials via high-throughput calculations.

Significantly suppressed thermal transport by doping In and Al atoms in gallium nitride.

Thermal transport plays a key role in the working stability of gallium nitride (GaN) based optoelectronic devices, where doping has been widely employed for practical applications. However, it remains unclear how doping affects thermal transport. In this study, based on first-principles calculations, we studied the doping effect on the thermal transport properties of GaN by substituting Ga with In/Al atoms. The thermal conductivities at 300 K along the in-plane(out-of-plane) directions of In- and Al-doped GaN are calculated to be 7.3(8.62) and 12.45(11.80) W m-1 K-1, respectively, which are more than one order of magnitude lower compared to that of GaN [242(239) W m-1 K-1]. From the analysis of phonon transport properties, we find that the low phonon group velocity and small phonon relaxation time dominate the degenerated thermal conductivity, which originated from the strong phonon anharmonicity of In/Al-doped GaN. Furthermore, by examining the crystal structure and electronic properties, the lowered thermal conductivity is revealed lying in the strong polarization of In-N and Al-N bonds, which is due to the large difference in electronegativity of In/Al and N atoms. The results achieved in this study have guiding significance to the thermal transport design of GaN-based optoelectronic devices.

Laboratory Measurements and Astronomical Search for Methoxyacetone and Methyl Methoxyacetate.

High-resolution pure rotational spectra of methoxyacetone and methyl methoxyacetate have been recorded and analyzed by using pulsed jet-expansion Fourier transform microwave spectroscopy with the aid of quantum calculations. The global minima for both target molecules have been detected in pulsed jet, whose spectra are featured with the splittings raised from the methyl internal rotations. On the basis of the spectroscopic results, a radio-astronomical search of methoxyacetone and methyl methoxyacetate was carried out toward the high-mass star-forming region Sgr B2(N) using the Shanghai Tianma 65 m radio telescope. No lines belonging to either of the target molecules were detected, and the upper limits to the column density were derived.

Asymmetric Non-Fullerene Small Molecule Acceptor with Unidirectional Non-Fused π-Bridge and Extended Terminal Group for High-Efficiency Organic Solar Cells.

We designed and synthesized an asymmetric non-fullerene small molecule acceptor (NF-SMA) IDT-TNIC with an A-D-π-A structure, based on an indacenodithiophene (IDT) central core, with a unidirectional non-fused alkylthio-thiophene (T) π-bridge, and 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1-ylidene)malononitrile (NIC) extended terminal groups. IDT-TNIC molecules still maintain a good coplanar structure, which benefits from the non-covalent conformational locks (NCL) between O···S and S···S. The asymmetric structure increases the molecular dipole moment, and the extended terminal group broadens the absorption of the material, resulting in an excellent photovoltaic performance of IDT-TNIC. The photovoltaic device, based on PBDB-T:IDT-TNIC, exhibits an energetic PCE of 11.32% with a high Voc of 0.87 V, high Jsc of 19.85 mA cm-2, and a low energy loss of 0.57 eV. More importantly, IDT-TNICs with asymmetric structures show a superior property compared to symmetric IDT-Ns. The results demonstrate that it is an effectual strategy to enhance the properties of asymmetric A-D-π-A-based NF-SMAs with non-fused NCL π-bridges and extended terminal groups.

Corrigendum to "Effects of Motor Training on Accuracy and Precision of Jaw and Finger Movements".

[This corrects the article DOI: 10.1155/2019/9593464.].

Effects of Motor Training on Accuracy and Precision of Jaw and Finger Movements.

Objective: To compare the effects of training of jaw and finger movements with and without visual feedback on precision and accuracy. Method: Twenty healthy participants (10 men and 10 women; mean age 24.6 ± 0.8 years) performed two tasks: a jaw open-close movement and a finger lifting task with and without visual feedback before and after 3-day training. Individually determined target positions for the jaw corresponded to 50% of the maximal jaw opening position, and a fixed target position of 20 mm was set for the finger. Movements were repeated 10 times each. The variability in the amplitude of the movements was expressed as percentage in relation to the target position (D accu-accuracy) and as coefficient of variation (CVprec-precision). Result: D accu and CVprec were significantly influenced by visual feedback (P = 0.001 and P < 0.001, respectively) and reduced after training jaw and finger movements (P < 0.001). D accu (P = 0.004) and CVprec (P = 0.019) were significantly different between jaw and finger movements. The relative changes in D accu (P = 0.017) and CVprec (P = 0.027) were different from pretraining to posttraining between jaw and finger movements. Conclusion: The accuracy and precision of standardized jaw and finger movements are dependent on visual feedback and appears to improve more by training in the trigeminal system possibly reflecting significant neuroplasticity in motor control mechanisms.

Recycling policy and statistical model of end-of-life vehicles in China.

In China, the number of end-of-life vehicles (ELVs) has reached an era of exponential growth because of continuous vehicle sales. The Chinese government has guided trends in the ELV recycling industry by implementing various recycling policies and expects most ELVs to be legally treated by licensed companies. The effects of subsidy policies are remarkable, and it was found that the effective adjustment of the subsidy is beneficial in increasing the recovery rate of ELVs without additional financial burden. Just as objects have their own end-of-life laws, different vehicle types have different life distribution curves and they are slightly influenced by government policies, especially subsidy policies. The aim of the study is to establish the logistics distribution functions for the passenger vehicles and commercial vehicles on the basis of the service years of 220,000 ELVs from 2012 to 2016 in Shanghai, and use a statistical model to predict and analyze the future trend of the number of the ELVs in China. Forecasts show that the number of ELVs in China will surpass 10 million in 2023.

Test-retest reliability of a new technique with pressure algometry applied to teeth in healthy Chinese individuals.

Pressure pain thresholds (PPTs) have been shown to be useful measures of mechanical pain sensitivity in deep tissues. However, clinical methods for measuring mechanical allodynia or hyperalgesia in teeth have not been reported. The aim of this study was to assess the reliability of PPTs in periodontal ligament of healthy Chinese participants. Twenty healthy young adults participated. Pressure pain thresholds were measured at six teeth and in two directions. The tests included three consecutive trials, in two separate sessions, which were performed on the first day by one examiner. After 1-3 wk, an identical protocol was carried out by two examiners, also in two separate sessions. There were no significant differences between repeated measures for all teeth. The PPTs had excellent reliability with high intraclass coefficients (ICCs) across different sessions (ICC: 0.871-0.956), days (ICC: 0.879-0.951), and examiners (ICC: 0.845-0.950). Pressure pain thresholds applied to the teeth have excellent intra- and inter-examiner agreement in healthy participants. This method may be proposed as an easy and reliable technique to assess mechanical pain sensitivity (e.g. mechanical allodynia and hyperalgesia) in the periodontal ligament, which is associated with endodontic or periodontal conditions.

[Simulation of Needle Reflectance Spectrum and Sensitivity Analysis of Biochemical Parameters of Pinus Yunnanensis in Different Healthy Status].

The sensitivity of biochemical effects on leaf reflectance is vital for retieving biochemical parameters with remote sensing. In this study, the chlorophyll and water absorption coefficients of the commonly used model LIBERTY (leaf incorporation biochemistry exhibiting reflectance and transmittance yields) were calibrated using field measured needle spectral reflectance curves based on a look up table (LUT) method. A novel spectra reflectance fitting method were presented by involving a new index (named as yellow index, YI), which could obviously improve the fitting accuracy of Pinus yunnanensis reflection spectrum at highly-stressed status. As a global sensitivity analysis method, the EFAST (extended Fourier amplitued sensitivity test) was implemented to quantitatively assess the sensitivity of biochemical parameters on needle reflectance. Results show that: (1) the reflectauce spectrum of healthy needles (R2=0.999，RMSE＜0.01), slightly stressed needles (R2=0.991, RMSE＜0.02) and moderately stressed needles (R2=0.992，RMSE＜0.03) are simulated fairly well by calibrated LIBERTY model which has less potential in fitting the reflectance spectrum of seriously stressed needles (R2=0.803，RMSE＞0.1). (2) the reflectance spectrum of seriously stressed needles can be successfully simulated by our proposed spectrum reflectance fitting method (R2=0.991, RMSE<0.03), because YI can quantitatively describe different degrees of stress, and (3) the sensitivity of leaf reflectance to chlorophyll and water parameters decreases with the degree of stress; while the sensitivity to other biochemical parameters is increasing, which includ baseline absorption, albino absorption, Lignin and Cellulose content, and nitrogen content, increases with the stress degree. Needle reflectance spectrum also have sensitivive bands for these parameters. For example, the albino absorption have a significant effect on needle reflectance in 505～565 and 705～850 nm). In addition, Albino absorption and chlorophyll also have significant effects on needle reflectance in visible region for seriously stressed needles, which indicates that the prior knowledge of the albino absorption level can help obtain the valid inversion result of chlorophyll content.

Fulminant type 1 diabetes with Shock rescue: a case report.

The shock in diabetes often requires rapid and adequate fluid administration, however, we report an anomalous case of fulminant type 1 diabetes mellitus (FT1DM) in which the patient's condition worsened following fluid administration. In May 2020, a 29-year-old male presented with blood glucose of 89.8 mmol/L and diabetic ketoacidosis after a week of gastroenteritis. The diagnosis was finalized after C-peptide and Hemoglobin A1c (HbA1c) measurement. The patient was admitted with shock and received a positive fluid balance of 2800 ml in 5 h, but his condition deteriorated and progressed to multi-organ failure. This study attempts to explain the possible mechanisms and focuses on high-risk factors associated with FT1DM. Therefore, meticulous monitoring and individualized fluid administration strategies are crucial for the management of FT1DM. This case provides beneficial insights for clinical treatment of this condition.

Impact of stand- and landscape-level variables on pine wilt disease-caused tree mortality in pine forests.

BACKGROUND: Pine wilt disease (PWD) outbreaks have affected extensive areas of South China's forests, but the factors explaining landscape patterns of pine mortality are poorly understood. The objective of this study was to determine the relative importance of stand structure, topography, landscape context, and beetle pressure in explaining PWD severity. During 2020-2021, we identified 66 plots based on mapped PWD infestation severity. We built PWD infestation maps for 2019-2021 through field surveys. Stand structure and topography were obtained from Forest Resources Management 'One Map' and elevation raster data. We then used 'One Map' and PWD infestation maps to determine landscape context and beetle pressure variables at different spatial scales. The relative importance of 12 explanatory variables was analyzed using multi-model inference. RESULTS: In this study, we show that: (i) 1 km was the best spatial scale related to pine mortality, and (ii) models including landscape context and beetle pressure were much better at predicting pine mortality than models using only stand-level variables. CONCLUSION: Landscape-level variables, particularly beetle pressure, were the most consistent predictors of subsequent pine mortality within susceptible stands. These results may help forest managers identify locations vulnerable to PWD and improve existing strategies for outbreak control. © 2023 Society of Chemical Industry.

Bubble Engineering on Micro-/Nanostructured Electrodes for Water Splitting.

Bubble behaviors play crucial roles in mass transfer and energy efficiency in gas evolution reactions. Combining multiscale structures and surface chemical compositions, micro-/nanostructured electrodes have drawn increasing attention. With the aim to identify the exciting opportunities and rationalize the electrode designs, in this review, we present our current comprehension of bubble engineering on micro-/nanostructured electrodes, focusing on water splitting. We first provide a brief introduction of gas wettability on micro-/nanostructured electrodes. Then we discuss the advantages of micro-/nanostructured electrodes for mass transfer (detailing the lowered overpotential, promoted supply of electrolyte, and faster bubble growth kinetics), localized electric field intensity, and electrode stability. Following that, we outline strategies for promoting bubble detachment and directional transportation. Finally, we offer our perspectives on this emerging field for future research directions.

Quantifying Hot Electron Energy Contributions in Plasmonic Photocatalysis Using Electrochemical Surface-Enhanced Raman Spectroscopy.

Due to the challenge in measuring hot electron energy under reaction conditions, very few studies focus on experimental determination of hot carrier energy. Here, we adjust the energy state of free electrons in Au nanoparticles to quantify the hot electron energy in plasmonic photocatalysis. Reactant molecules with different reduction potentials such as 4-nitrothiophenol (4-NTP), 4-iodothiophenol (4-ITP), etc. are chosen as molecular probes to investigate the reducing ability of hot electrons. By comparing the voltage required to achieve the same conversion of photo- and electro-reaction pathways, we calibrate the maximum energy efficiency of hot electrons in 4-NTP reduction to be 0.32 eV, which is much lower than the excitation photon energy of 1.96 eV. Our work provides insight into the energy distribution of hot electrons and will be helpful for rational design of highly efficient plasmon-mediated chemical reactions.

Anisotropic Optical, Mechanical, and Thermoelectric Properties of Two-Dimensional Fullerene Networks.

Nanoclusters like fullerenes as the unit to build intriguing two-dimensional (2D) topological structures is of great challenge. Here we propose three bridged fullerene monolayers and comprehensively investigate the novel fullerene monolayer (α-C60-2D) as synthesized experimentally [Hou et al. Nature 2022, 606, 507-510] by state-of-the-art first-principles calculations. Our results show that α-C60-2D has a direct band gap of 1.55 eV close to the experimental value, an optical linear dichroism with strong absorption in the long-wave ultraviolet region, a small anisotropic Young's modulus, a large hole mobility, and an ultrahigh Seebeck coefficient at middle-low temperatures. It is unveiled that the anisotropic optical, mechanical, electrical, and thermoelectric properties of α-C60-2D originate from the asymmetric bridging arrangements between C60 clusters. Our study promises potential applications of monolayer fullerene networks in lots of fields.

Universal linker-free assembly of core-satellite hetero-superstructures.

Colloidal superstructures comprising hetero-building blocks often show unanticipated physical and chemical properties. Here, we present a universal assembly methodology to prepare hetero-superstructures. This straightforward methodology allows the assembly of building block materials varying from inorganic nanoparticles to living cells to form superstructures. No molecular linker is required to bind the building blocks together and thus the products do not contain any unwanted adscititious material. The Fourier transform infrared spectra, high resolution transmission electron microscopic images and nanoparticle adhesion force measurement results reveal that the key to self-organization is stripping surface ligands by adding non-polar solvents or neutralizing surface charge by adding salts, which allow us to tune the balance between van der Waals attraction and electrostatic repulsion in the colloid so as to trigger the assembling process. As a proof-of-concept, the superior photocatalytic activity and single-particle surface-enhanced Raman scattering of the corresponding superstructures are demonstrated. Our methodology greatly extends the scope of building blocks for superstructure assembly and enables scalable construction of colloidal multifunctional materials.

The record low thermal conductivity of monolayer cuprous iodide (CuI) with a direct wide bandgap.

Two-dimensional materials have attracted significant research interest due to the fantastic properties that are unique to their bulk counterparts. In this paper, from the state-of-the-art first-principles, we predicted the stable structure of a monolayer counterpart of γ-CuI (cuprous iodide) that is a p-type wide bandgap semiconductor. The monolayer CuI presents multifunctional superiority in terms of electronic, optical, and thermal transport properties. Specifically, the ultralow thermal conductivity of 0.116 W m-1 K-1 is predicted for monolayer CuI, which is much lower than those of γ-CuI (0.997 W m-1 K-1) and other typical semiconductors. Moreover, an ultrawide direct bandgap of 3.57 eV is found in monolayer CuI, which is even larger than that of γ-CuI (2.95-3.1 eV), promising for applications in nano-/optoelectronics with better optical performance. The ultralow thermal conductivity and direct wide bandgap of monolayer CuI as reported in this study would promise its potential applications in transparent and wearable electronics.