Dual-Defect Engineering Strategy Enables High-Durability Rechargeable Magnesium-Metal Batteries

Rechargeable magnesium-metal batteries(RMMBs)are promising next-generation secondary batteries;however,their development is inhibited by the low capacity and short cycle lifespan of cathodes.Although various strategies have been devised to enhance the Mg^(2+)migration kinetics and structural stability of cathodes,they fail to improve electronic conductivity,rendering the cathodes incompatible with magnesium-metal anodes.Herein,we propose a dual-defect engineering strategy,namely,the incorporation of Mg^(2+)pre-intercalation defect(P-Mgd)and oxygen defect(Od),to simultaneously improve the Mg^(2+)migration kinetics,structural stability,and electronic conductivity of the cathodes of RMMBs.Using lamellar V_(2)O_(5)·nH_(2)O as a demo cathode material,we prepare a cathode comprising Mg_(0.07)V_(2)O_(5)·1.4H_(2)O nanobelts composited with reduced graphene oxide(MVOH/rGO)with P-Mgd and Od.The Od enlarges interlayer spacing,accelerates Mg^(2+)migration kinetics,and prevents structural collapse,while the P-Mgd stabilizes the lamellar structure and increases electronic conductivity.Consequently,the MVOH/rGO cathode exhibits a high capacity of 197 mAh g^(−1),and the developed Mg foil//MVOH/rGO full cell demonstrates an incredible lifespan of 850 cycles at 0.1 A g^(−1),capable of powering a light-emitting diode.The proposed dual-defect engineering strategy provides new insights into developing high-durability,high-capacity cathodes,advancing the practical application of RMMBs,and other new secondary batteries.

Prospect of Hexagonal CsMg(I_(1-x)Br_(x))_(3) Alloys for Deep-Ultraviolet Light Emission

Materials for deep-ultraviolet(DUV)light emission are extremely rare,significantly limiting the development of efficient DUV light-emitting diodes.Here we report CsMg(I_(1−x)Br_(x))_(3) alloys as potential DUV light emitters.Based on rigorous first-principles hybrid functional calculations,we find that CsMgI_(3) has an indirect bandgap,while CsMgBr_(3) has a direct bandgap.Further,we employ a band unfolding technique for alloy supercell calculations to investigate the critical Br concentration in CsMg(I_(1−x)Br_(x))_(3) associated with the crossover from an indirect to a direct bandgap,which is found to be∼0.36.Thus,CsMg(I_(1−x)Br_(x))_(3) alloys with 0.366≤6≤1 cover a wide range of direct bandgap(4.38–5.37 eV;284–231 nm),falling well into the DUV regime.Our study will guide the development of efficient DUV light emitters.

Profiling Electronic and Phononic Band Structures of Semiconductors at Finite Temperatures: Methods and Applications

Semiconductor devices are often operated at elevated temperatures that are well above zero Kelvin,which is the temperature in most first-principles density functional calculations.Computational approaches to com-puting and understanding the properties of semiconductors at finite temperatures are thus in critical demand.In this review,we discuss the recent progress in computationally assessing the electronic and phononic band structures of semiconductors at finite temperatures.As an emerging semiconductor with particularly strong temperature-induced renormalization of the electronic and phononic band structures,halide perovskites are used as a representative example to demonstrate how computational advances may help to understand the band struc-tures at elevated temperatures.Finally,we briefly illustrate the remaining computational challenges and outlook promising research directions that may help to guide future research in this field.

Origin of the Disparity between the Stability of Transmutated Mix-Cation and Mix-Anion Compounds

Transmutation is an efficient approach for material design. For example, ternary compound CuGaSe_(2) in chalcopyrite structure is a promising material for novel optoelectronic and thermoelectric device applications. It can be considered as formed from the binary host compound ZnSe in zinc-blende structure by cation transmutation(i.e., replacing two Zn atoms by one Cu and one Ga). While cation-transmutated materials are common, aniontransmutated ternary materials are rare, for example, Zn_(2)As Br(i.e., replacing two Se atoms by one As and one Br)is not reported. The physical origin for this puzzling disparity is unclear. In this work, we employ first-principles calculations to address this issue, and find that the distinct differences in stability between cation-transmutated(mix-cation) and anion-transmutated(mix-anion) compounds originate from their different trends of ionic radii as functions of their ionic state, i.e., for cations, the radius decreases with the increasing ionic state, whereas for anions, the radius increases with the increasing absolute ionic state. Therefore, for mix-cation compounds,the strain energy and Coulomb energy can be simultaneously optimized to make these materials stable. In contrast, for mix-anion systems, minimization of Coulomb energy will increase the strain energy, thus the system becomes unstable or less stable. Thus, the trend of decreasing strain energy and Coulomb energy is consistent in mix-cation compounds, while it is opposite in mix-anion compounds. Furthermore, the study suggests that the stability strategy for mix-anion compounds can be controlled by the ratio of ionic radii r3/r1, with a smaller ratio indicating greater stability. Our work, thus, elucidates the intrinsic stability trend of transmutated materials and provides guidelines for the design of novel ternary materials for various device applications.

卓越大学联盟国内外高校科研合作机会发现

[目的/意义]高水平的社会科学科研成果产出可以有效促进理工科大学的科学研究问题的解决。研究卓越大学联盟高校与国内外高校的科研合作机会,旨在最大化科研效率,为卓越大学联盟科研过程中合作对象的选择提供指导。[方法/过程]以卓越大学联盟与国内外20所高校10年间的SSCI论文为数据源,建立共有机构合作网络和主题网络,分别借助网络路径相似性指标U-Katz和节点相似性指标Cosine,衡量卓越大学联盟与国内外高校间合作机会。[结果/结论]以合作潜力值表示高校间的合作潜力高低,从而挖掘出卓越大学联盟与国内外高校潜在合作机会,并尝试给出潜在合作领域内的研究者。结合潜在合作动机以及潜在合作方向,对高校机构、科研工作者如何利用潜在合作信息开展科研合作提出相关建议。

Combined detection of plasma GATA5 and SFRP2 methylation is a valid noninvasive biomarker for colorectal cancer and adenomas

AIM:To investigate GATA5,SFRP2,and ITGA4 methylation in plasma DNA as noninvasive biomarkers for colorectal cancer(CRC) or adenomas.METHODS:There were 57 CRC patients,30 adenomas patients,and 47 control patients enrolled in this study.Methylation-specific polymerase chain reaction was used to determine the promoter methylation status of GATA5,SFRP2,and ITGA4 genes in plasma DNA,and their association with clinical outcome in CRC.The predictive ability of GATA5,SFRP2,and ITGA4 methylation,individually or in combination,to detect CRC or adenomas was further analyzed.RESULTS:Hypermethylated GATA5 was detected in plasma in 61.4%(35/57) of CRC cases,43.33%(13/30) of adenoma cases,and 21.28%(10/47) of control cases.The hypermethylation of SFRP2 was detected in 54.39%(31/57),40.00%(12/30),and 27.66%(13/47) in plasma samples from CRC,adenomas,and controls,respectively.ITGA4 methylation was detected in 36.84%(21/57) of plasma samples of CRC patients and in 30.00%(9/30) of plasma samples from patients with colorectal adenomas,and the specificity of this individual biomarker was 80.85%(9/47).Moreover,GATA5 methylation in the plasma was significantly correlated with larger tumor size(P =0.019),differentiation status(P =0.038),TNM stage(P =0.008),and lymph node metastasis(P =0.008).SFRP2 and ITGA4 methylation in plasma significantly correlated with differentiation status(SFRP2,P =0.012; ITGA4,P =0.007),TNM stage(SFRP2,P =0.034; ITGA4,P =0.021),and lymph node metastasis(SFRP2,P =0.034; ITGA4,P =0.021).From the perspective of predictive power and cost-performance,using GATA5 and SFRP2 together as methylation markers seemed the most favorable predictor for CRC(OR =8.06;95%CI:2.54-25.5; P < 0.01) and adenomas(OR =3.35; 95%CI:1.29-8.71; P =0.012).CONCLUSION:A combination of GATA5 and SFRP2 methylation could be promising as a marker for the detection and diagnosis of CRC and adenomas.

A Correntropy-based Affine Iterative Closest Point Algorithm for Robust Point Set Registration

The iterative closest point(ICP)algorithm has the advantages of high accuracy and fast speed for point set registration,but it performs poorly when the point set has a large number of noisy outliers.To solve this problem,we propose a new affine registration algorithm based on correntropy which works well in the affine registration of point sets with outliers.Firstly,we substitute the traditional measure of least squares with a maximum correntropy criterion to build a new registration model,which can avoid the influence of outliers.To maximize the objective function,we then propose a robust affine ICP algorithm.At each iteration of this new algorithm,we set up the index mapping of two point sets according to the known transformation,and then compute the closed-form solution of the new transformation according to the known index mapping.Similar to the traditional ICP algorithm,our algorithm converges to a local maximum monotonously for any given initial value.Finally,the robustness and high efficiency of affine ICP algorithm based on correntropy are demonstrated by 2D and 3D point set registration experiments.

Estimated biomass carbon in thinned Cunninghamia lanceolate plantations at different stand-ages

Chinese fir(Cunninghamia lanceolate[Lamb.]Hook.)is a fast-growing species which is not only important as a timber-supplier,but also as an available sink for carbon(C)storage in biomass.Stand age and density are two critical factors that can determine tree C sequestration as interrelated drivers through natural self-thinning.C.lanceolate were planted using 1-year-old bare-root seedlings at the initial density of 1800 stems ha^(-1)in a 15-ha montane area of Hunan Province,China in 1987.The plantation was thinned twice 10 and 20 years after planting to leave trees of437.5±26.6,675.0±155.2 and 895.8±60.1 stems ha^(-1)as low,medium,and high densities,respectively.Tree height and diameter at breast height(DBH)were measured every2 years beginning from 23 years(2009)to 31 years(2018)after establishment,timber volume(TV)and biomass C were estimated accordingly.We did not find any interactive effect of age and density on any variables except for height.Both TV and biomass C increased with stand age or decreased in higher densities.The allometric heightDBH relationship can be fitted by an exponential risingto-maximum model with higher maximum value over time.The decline of biomass C along density fit with the inverse first-order polynomial model which indicated that at least1300-1500 stems ha^(-1)may be needed to maximize TV and biomass C for a longer term over 20 years.Therefore,to control the density to a reasonable level,over 1300 stems ha^(-1)in a rotation over 20 years old will be practical for tree biomass C in Chinese fir plantations.

不同方向石墨烯片构筑纳米孔隙浸润特征

以石墨烯为基质构筑的纳米孔隙存在两种壁面结构,水滴浸润纳米孔隙在微流动方面至关重要.本文鉴于实验报道的石墨烯结构,构建了两种石墨烯纳米孔隙,利用全原子分子动力学模拟方法研究了纳米水滴浸润两种纳米孔隙.发现两种不同排列石墨烯构筑相同尺度的纳米孔隙展现出完全不同的浸润特点,一种是放置在纳米孔隙入口处的水滴会自发浸润孔隙,另一种是水滴完全不会浸润孔隙.通过分析两种纳米孔隙结构,总结出了产生上述现象主要归因于纳米孔隙内外表面的润湿性差异.建立了纳米孔隙内外表面完全一样的结构,构建了水滴浸润纳米孔隙的润湿性相图,给出了水滴浸润纳米孔隙的一般性规律.

Ion-ion reactions for charge reduction of biopolymer at atmospheric pressure ambient

Extractive electrospray ionization source （EESI） was adapted for ion-ion reaction, which was demonstrated by using a linear quadrupole ion trap mass spectrometer for the first ion-ion reaction of biopolymers in the atmospheric pressure ambient.

A PTEN translational isoform has PTEN-like activity

Background： To identify PTEN isoform and explore its potential role in tumor suppression. Methods： Western blotting, over-expression, shRNA mediated knocking-down, and bioinformatic analysis were used to identify PTEN isoform and test its effect on PI3K-Akt signaling pathway. Cell proliferation, apoptosis, and migration assays were used to test PTEN isoform＇s biological activities. Results： The PTEN isoform is about 15 kDa bigger than PTEN and its expression is dependent on PTEN status. Immunoprecipitation for PTEN isoform followed by screening with antibodies against ISG15, SUMO1/2/3, Ubiquitin, and Nedd8 showed the identified PTEN isoform is not a general proteinaceous post-translational modification. In addition, overexpression of PTEN cDNA in cells did not generate PTEN isoform whereas knocking-down of PTEN reduced the protein levels of both PTEN and PTEN isoform in a proportional manner. Analysis of PTEN DNA sequence disclosed an alternative translational starting code （CTG） upstream of canonical PTEN coding sequence. Expression of cloned PTEN isoform generated a protein with a size about 15 kDa bigger than PTEN and suppressed PI3K-Akt signaling pathway in cells. Overexpression of PTEN isoform also led to decrease in cell growth and enhanced serum starvation--and UV irradiation--induced apoptosis through activation of Caspase 3. Finally, expression of PTEN isoform inhibited cell migration in scratch assay. Conclusions： PTEN isoform has PTEN-Iike activity and might be a new tumor suppressor.

Slag formation path during dephosphorization process in a converter

The slag formation path is important for efficient dephosphorization in steelmaking processes. The phosphorus capacity and the melting properties of the slag are critical parameters for optimizing the slag formation path. Regarding these two factors, the phosphorus partition ratio was calculated using the regular solution model （RSM）, whereas the liquidus diagrams of the slag systems were estimated using the FactSage thermodynamic package. A slag formation path that satisfies the different requirements of dephosphorization at different stages of dephosphorization in a converter was thus established through a combination of these two aspects. The composition of the initial slag was considered to be approximately 15wt%CaO-44wt% SiOz-41wt%FeO. During the dephosphorization process, a slag formation path that follows a high-iron route would facilitate efficient dephosphorization. The composition of the final dephosphorization slag should be approximately 53wt%CaO-25.Swt% SiO2-21.5wt%FeO. The composition of the final solid slag after dephosphorization is approximately 63.6wt%CaO-30.3wt%SiO2-6. 1wt%FeO.

Advances and challenges in DFT-based energy materials design

The growing worldwide energy needs call for developing novel materials for energy applications.Ab initio density functional theory(DFT)calculations allow the understanding and prediction of material properties at the atomic scale,thus,play an important role in energy materials design.Due to the fast progress of computer power and development of calculation methodologies,DFT-based calculations have greatly improved their predictive power,and are now leading to a paradigm shift towards theory-driven materials design.The aim of this perspective is to introduce the advances in DFT calculations which accelerate energy materials design.We first present state-of-the-art DFT methods for accurate simulation of various key properties of energy materials.Then we show examples of how these advances lead to the discovery of new energy materials for photovoltaic,photocatalytic,thermoelectric,and battery applications.The challenges and future research directions in computational design of energy materials are highlighted at the end.

Fault Diagnosis Technology Based on Model Driven

Fault diagnosis is an important application of the power grids monitoring system. Under the situation of continuous development of smart grid, it brings new challenges to the fault diagnosis technology. A fault diagnosis expert system based on model driven approach is proposed in this paper. And the corresponding fault modeling technology based on Fault Logic Description Language (FLDL) is described step by step. Practices show that this system could meet the requirements of processing fault alarm information rapidly and reliably by operator.

Manipulating single oxygen at Cu_(2)O-island surfaces through thermomechanical coupling

Single oxygen diffusion event,the most favorable rate-limiting process of epitaxial Cu_(2)O oxide-island layerby-layer growth kinetics,may lead to oxygen defects due to thermomechanical coupling.However,the formation rules of oxygen defects remain unclear,preventing the realization of controllable oxygen defects on oxide-island surfaces.Here,we utilize the first-principles method to investigate the formation rules of intrinsic oxygen defects in the surface layers of prototypical metal-oxide(Cu_(2)O)surfaces under thermomechanical coupling effects.We establish the thermodynamic phase diagram for oxygen-defect-modulated Cu_(2)O surfaces,enabling the prediction of the growth of oxide islands during Cu oxidation,which aligns closely with in-situ environmental transmission electron microscopy(ETEM)experiment observations.By exploring the strain-modulated phase diagrams,we propose a potential strategy for controlling the type and concentration of oxygen defects on oxide-island surfaces.Our findings provide an effective approach to theoretically understanding the oxidation process of metal surfaces,thus enabling the computational design of high-performance corrosion-resistant surfaces.

CrMnFeCoNi高熵合金纳米晶温度相关的拉伸行为研究

高熵合金是一种由多种主元元素组成的新型合金.实验研究表明等原子比CrMnFeCoNi高熵合金在低温下具有比室温更高的拉伸强度和断裂韧性.论文针对这一现象,利用分子动力学模拟对平均晶粒尺寸为6.18 nm的CrMnFeCoNi纳米晶在300、200和77 K下分别进行拉伸模拟.模拟研究揭示了纳米尺度CrMnFeCoNi高熵合金力学行为的温度效应和强韧机理.微结构演化分析表明:随着温度的降低,塑性变形阶段滑移系开动的越少,位错滑移所受的阻力越大,屈服强度和抗拉强度越大;温度越低,模型破坏时,孔洞缺陷形核较慢,更多孔洞缺陷演化成断口,更多的孔洞和断口分摊拉伸应变,使得高熵合金纳米晶的低温韧性更好.

High-efficiency 50 W burst-mode hundred picosecond green laser

We report high-energy,high-efficiency second harmonic generation in a near-infrared all-solid-state burst-mode picosecond laser at a repetition rate of 1 kHz with four pulses per burst using a type-I noncritical phase-matching lithium triborate crystal.The pulses in each burst have the same time delay(~1 ns),the same pulse duration(~100 ps)and different relative amplitudes that can be adjusted separately.A mode-locked beam from a semiconductor saturable absorber mirror is pulse-stretched,split into seed pulses and injected into a Nd:YAG regenerative amplifier.After the beam is reshaped by aspheric lenses,a two-stage master oscillator power amplifier and 4f imaging systems are applied to obtain a high power of^100 W.The 532 nm green laser has a maximum conversion efficiency of 68%,an average power of up to 50 W and a beam quality factor M^2 of 3.5.

Atomic structures of twin boundaries in hexagonal closepacked metallic crystals with particular focus on Mg

We have investigated twin boundaries in double-lattice hexagonal close-packed metallic materials,focusing on their atomic geometry.Combining accurate ab-initio methods and large-scale atomistic simulations we address the following two fundamental questions:(i)What are the possible intrinsic twin boundary structures in hcp crystals?(ii)Are these structures stable against small distortions?In order to help end a decade-long controversy over the experimental observations of the atomic structures of twin boundaries,we have determined the energetics,spectra,and transition mechanisms of the twin boundaries.Our results confirm that the mechanical stability controls structures which are observed.

Morphological Control of Biochar with Emerging Functionalities by Thermodynamic and Kinetic Approaches

Functional materials with controllable morphology and structural compositions starting from natural precursors using environmentally friendly processes are an appealing topic in materials chemistry today.Encompassing environmental and economic issues,much attention has recently been focused on the use of biomass to produce functional carbonaceous materials.The conversion of biomass to highly valuable“green”carbonaceous materials by a process of low-temperature hydrothermal carbonization(HTC)other than traditional high-temperature HTC or pyrolysis is crucial because it allows fine control of the morphology and structural compositions in order to meet the desired applications.Low-temperature HTC was generally performed with renewable resources(e.g.,glucose and fructose)in an aqueous medium in the temperature range of 160−250°C under self-generated pressure.However,traditional HTC materials prepared by this straightforward method are commonly irregular and bulky.The relatively high temperature,weak assembly ability of carbohydrate-derived carbon domains,and complicated tandem reactions severely limited the development of HTC.The ability to control the assembly during the HTC process to shape the microstructure of carbonaceous materials remains a key synthetic objective.Moreover,it is anticipated that the synthetic protocols developed to solve this challenge ought to reasonably remain simple,nontoxic,and cost-effective.To address these issues,we have developed several methods in terms of precise control of the microstructure(i.e.,morphology,pore size and structure,and hybrid nanostructure)through manipulating the thermodynamic and kinetic behavior,enabling access to a wide range of compositions and applications.The focus of this Account revolves around new methodologies to access carbonaceous materials with special morphology and nanoarchitecture that could not be easily prepared previously,as developed by our group.We first started with a kinetically controlled soft-templating strategy to enable the preparation of a series of carbonaceous materials or hybrid materials with ordered porous and various morphological structures.Next,the improvement of HTC occurred through-polymer-/polyelectrolyte-assisted structure formation and facile yet efficient processes to prepare monodisperse primary nanoparticles or secondary superstructures.In subsequent sections,we present how to control the packing parameter or utilize template properties during the assembly process for asymmetric construction and anisotropic growth.The benefits for applications raised from the special control of HTC carbonaceous materials are also discussed.Finally,a brief summary of challenges and opportunities in this field is presented.

Graph deep learning accelerated efficient crystal structure search and feature extraction

Structural search and feature extraction are a central subject in modern materials design,the efficiency of which is currently limited,but can be potentially boosted by machine learning(ML).Here,we develop an ML-based prediction-analysis framework,which includes a symmetry-based combinatorial crystal optimization program(SCCOP)and a feature additive attribution model,to significantly reduce computational costs and to extract property-related structural features.Our method is highly accurate and predictive,and extracts structural features from desired structures to guide materials design.We first test SCCOP on 35 typical compounds to demonstrate its generality.As a case study,we apply our approach to a two-dimensional B-C-N system,which identifies 28 previously undiscovered stable structures out of 82 compositions;our analysis further establishes the structural features that contribute most to energy and bandgap.Compared to conventional approaches,SCCOP is about 10 times faster while maintaining a comparable accuracy.Our framework is generally applicable to all types of systems for precise and efficient structural search,providing insights into the relationship between ML-extracted structural features and physical properties.