Stress-Regulation Design of Lithium Alloy Electrode toward Stable Battery Cycling

Metallic tin(Sn)foil is a promising candidate anode for lithium-ion batteries(LIBs)due to its metallurgical processability and high capacity.However,it suffers low initial Coulombic efficiency and inferior cycling stability due to its uneven alloying/dealloying reactions,large volume change and stress,and fast electrode structural degradation.Herein,we report an undulating LiSn electrode fabricated by a scalable two-step procedure involving mechanical lithography and chemical prelithiation of Sn foil.With the combination of experimental measurements and chemo-mechanical simulations,it was revealed the obtained undulating LiSn/Sn electrode could ensure better mechanical stability due to the pre-swelling state from Sn to Li x Sn and undulating structure of lithography in comparison with plane Sn,homogenize the electrochemical alloying/dealloying reactions due to the activated surface materials,and compensate Li loss during cycling due to the introduction of excess Li from Li_(x)Sn,thus enabling enhanced electrochemical performance.Symmetric cells consisting of undulating LiSn/Sn electrode with an active thickness of∼5 um displayed stable cycling over 1000 h at 1 mA cm^(-2) and 1 mAh cm^(-2) with a low average overpotential of<15 mV.When paired with commercial LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)cathode with high mass loading of 15.8 mg cm^(-2),the full cell demonstrated a high capacity of 2.4 mAh cm^(-2) and outstanding cycling stability with 84.9% capacity retention at 0.5 C after 100 cycles.This work presents an advanced LiSn electrode with stress-regulation design toward high-performance LIBs,and sheds light on the rational electrode design and processing of other high-capacity lithium alloy anodes.

丁腈橡胶序列结构对其硫化速率及力学性能的影响

通过核磁共振技术(NMR)研究了丁腈橡胶中丙烯腈(AN)与丁二烯(BD)的序列结构对丁腈橡胶的硫化速率、拉伸性能的影响。结果表明,非极高腈品级丁腈橡胶的序列结构共有BAB、BBB、BBA/ABB、ABA 4种;丙烯腈含量相同的丁腈橡胶的序列结构有很大的差异,且其硫化速率及力学性能受序列结构的影响很大。当BAB序列结构含量增加2.7%,焦烧时间缩短0.48 min,拉伸强度增加2.34 MPa,断裂伸长率增加80.52%。当BBB序列结构含量增加5.9%,正硫化时间缩短2.89 min。

低分子量聚异戊二烯液体橡胶的结构表征及燃烧特性

以正丁基锂为引发剂,四氢呋喃(THF)为调节剂,通过核磁共振技术(NMR)研究了不同溶液体系对低分子量聚异戊二烯(LIR)结构的影响及LIR液体橡胶的燃烧行为。结果表明,在40℃,反应时间为4 h,异戊二烯单体浓度为30%的实验条件下,THF能够有效地调控LIR的结构,且能够稳定合成高cis-1,4-结构含量的低分子量液体异戊二烯橡胶。以微型量热仪(MCC)等研究了不同构型LIR的燃烧特性,LIR的3,4-结构能够提高LIR的燃烧性能,结果显示,3,4-结构含量每增加5%,热释放速率(HRR)值升高36 W/g。

Abundant heterointerfaces in MOF-derived hollow CoS_(2)-MoS_(2) nanosheet array electrocatalysts for overall water splitting

Rational coupling of hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) catalysts is extremely important for practical overall water splitting,but it is still challenging to construct such bifunctional heterostructures.Herein,we present a metal-organic framework(MOF)-etching strategy to design free-standing and hierarchical hollow CoS_(2)-MoS_(2) heteronanosheet arrays for both HER and OER.Resulting from the controllable etching of MOF by MoO_(4)^(2-) and in-situ sulfuration,the obtained CoS_(2)-MoS_(2) possesses abundant heterointerfaces with modulated local charge distribution,which promote water dissociation and rapid electrocatalytic kinetics.Moreover,the two-dimensional hollow array architecture can not only afford rich surface-active sites,but also facilitate the penetration of electrolytes and the release of evolved H_(2)/O_(2) bubbles.Consequently,the engineered CoS_(2)-MoS_(2) heterostructure exhibits small overpotentials of 82 mV for HER and 266 mV for OER at 10 mA cm^(-2).The corresponding alkaline electrolyzer affords a cell voltage of 1.56 V at 10 mA cm^(-2) to boost overall water splitting,along with robust durability over 24 h, even surpassing the benchmark electrode couple composed of IrO_(2) and Pt/C The present work may provide valuable insights for developing MOF-derived heterogeneous electrocatalysts with tailored interface/surface structure for widespread application in catalysis and other energyrelated areas.

Efficient Secure Data Provenance Scheme in Multimedia Outsourcing and Sharing

To cope with privacy leakage caused by multimedia outsourcing and sharing,data provenance is used to analyze leaked multimedia and provide reactive accountability.Existing schemes of multimedia provenance are based on watermarking protocols.In an outsourcing scenario,existing schemes face two severe challenges:1)when data leakage occurs,there exists a probability that data provenance results can be repudiated,in which case data provenance tracking fails;and 2)when outsourced data are shared,data encryption transfer causes key management burden outside the schemes,and privacy leakage threatens users.In this paper,we propose a novel data provenance scheme with an improved LUT-based fingerprinting protocol,which integrates an asymmetric watermarking protocol,robust watermark algorithm and homomorphic encryption and digital signatures to achieve full non-repudiation provenance.We build an in-scheme stream cipher to protect outsourced multimedia data from privacy leakage and complicated key management.Our scheme is also lightweight and easy to deploy.Extensive security and performance analysis compares our scheme with the state of the art.The results show that our scheme has not only better provenance security and data confidentiality but also higher efficiency for multimedia outsourcing,sharing and provenance.

Whole brain radiotherapy concomitant or sequential Vm26/DDP in treating small cell lung cancer patients with brain metastases

Objective： The aim of the study was to compare efficacies and safeties of 2 different treatments of whole brain radiotherapy （WBRT） sequential or concomitant Vm26/DDP for small cell lung cancer （SCLC） patients with brain metastases. Methods： A total of 39 patients were randomly divided into sequential chemoradiotherapy regime （A group, 20 patients） and concomitant chemoradiotherapy regime （B group, 19 patients）. The close of WBRT was 36 Gy in 18-20 fractions, chemotherapy of Vm26/DDP regimen with teniposide 60 mg/m^2 on dl to d3 and cisplatin 20 mg/m^2 on dl to d5, repeating every 3 weeks. The response was evaluated after WBRT and 2 cycles of chemotherapy. Results： Total response rates of A and B groups were 70.0% and 78.9% respectively （P = 0.520）. The median survival was 11 months in A group and 10 months in B group. Six, twelve and eighteen months cumulative survival rates of A and B groups were 75.0%, 42.5%, 26.2%, and 81.6%, 26.4%, 10.5%, respectively （χ^2 = 0.383, P 〉 0.05）. Response rate and the number of brain metastases were independent prognostic factors. Conclusion： Both sequential and concomitant chemoradiotherapy groups are effective, and the main toxicity with myelosuppression is tolerable after therapy. It can be applied firstly and effectively to the SCLC patients with brain metastases in clinic.

Adsorption and rotational barrier for a single azobenzene molecule on Au(111)surface

The orientation switching of a single azobenzene molecule on Au(111)surface excited by tunneling electrons and/or photons has been demonstrated in recent experiments.Here we investigate the rotation behavior of this molecular rotor by first-principles density functional theory(DFT)calculation.The anchor phenyl ring prefers adsorption on top of the fcc hollow site,simulated by a benzene molecule on close packed atomic surface.The adsorption energy for an azobenzene molecule on Au(111)surface is calculated to be about 1.76 eV.The rotational energy profile has been mapped with one of the phenyl rings pivots around the fcc hollow site,illustrating a potential barrier about 50 meV.The results are consistent with experimental observations and valuable for exploring a broad spectrum of molecules on this noble metal surface.

Emission Behaviors of Submicron Particles(PM_(1))Generated by the Combustion of Sesame Stalk after Combined Water Washing and Carbonization Pretreatment

Pretreatment before biomass combustion is significant for its efficient utilization and that combined water washing and carbonization can be efficient.An agricultural processing residues sesame stalk was selected and carried out two pretreatments separately,i.e.,water washing-torrefaction(W-T)and torrefaction-water washing(T-W),to explore the effect on the fuel properties,combustion characteristics and particulate matter(PM)emission.The obtained biochar was also combusted under air and oxy50(CO_(2):O_(2)=50:50)conditions for the sake of investigating the effect of pretreatment and combustion atmosphere.The results indicate that,W-T and T-W both not only have great effect on the improvement of fuel properties but also reduce the content of water-soluble elements like K,Cl,etc.Due to the difference in hydrophobicity,the biochar obtained by W-T have the optimal fuel properties.At the same time,the pretreatment also hinder the combustion in a certain extent in which the comprehensive combustion characteristics(SN)show a downward trend.Furthermore,both two pretreatments have obvious benefit on the reduction of PM_(1)emission and W-T have the best effect related to the higher removal efficiency of inorganic elements(especially K+Na+Cl+S).Under oxy50 condition,the oxygen concentration and combustion temperature is higher,improving the sulfation of K and vaporization of Ca,P and Mg which result in weakening in the pretreatment reduction effect on PM_(1)emission.

Large Cohort Data Based Cost-Effective Disease Prevention Design Strategy: Strong Heart Study

Background and Objective: A multitude of large cohort studies have collected data on incidence and covariates/risk factors of various chronic diseases. However, approaches for utilization of these large data and translation of the valuable results to inform and guide clinical disease prevention practice are not well developed. In this paper, we proposed, based on large cohort study data, a novel conceptual cost-effective disease prevention design strategy for a target group when it is not affordable to include everyone in the target group for intervention. Methods and Results: Data from American Indian participants (n = 3516;2056 women) aged 45 - 74 years in the Strong Heart Study, the diabetes risk prediction model from the study, a utility function, and regression models were used. A conceptual cost-effective disease prevention design strategy based on large cohort data was initiated. The application of the proposed strategy for diabetes prevention was illustrated. Discussion: The strategy may provide reasonable solutions to address cost-effective prevention design issues. These issues include complex associations of a disease with its significant risk factors, cost-effectively selecting individuals at high risk of developing disease to undergo intervention, individual differences in health conditions, choosing intervention risk factors and setting their appropriate, attainable, gradual and adaptive goal levels for different subgroups, and assessing effectiveness of the prevention program. Conclusions: The strategy and methods shown in the illustrative example can also be analogously adopted and applied to other diseases preventions. The proposed strategy provides a way to translate and apply epidemiological study results to clinical disease prevention practice.

Large Cohort Data Based Group or Community Disease Prevention Design Strategy: Strong Heart Study

Background and Objective: A multitude of large cohort studies have data on incidence rates and predictors of various chronic diseases. However, approaches for utilization of these costly collected data and translation of these?valuable results to inform and guide clinical disease prevention practice are?not well developed. In this paper we proposed a novel conceptual group/community disease prevention design strategy based on large cohort study data. Methods and Results: The data from participants (n = 3516;2056 women) aged 45 to 74 years and the diabetes risk prediction model from Strong Heart Study were used. The Strong Heart Study is a population-based cohort study of cardiovascular disease and its risk factors in American Indians. A conceptual group/community disease prevention design strategy based on large cohort data was initiated. The application of the proposed strategy for group diabetes prevention was illustrated. Discussion: The strategy may provide reasonable solutions to the prevention design issues. These issues include complex associations of a disease with its combined and correlated risk factors, individual differences, choosing intervention risk factors and setting their appropriate, attainable, gradual and adaptive goal levels for different subgroups, and assessing effectiveness of the prevention program. Conclusions: The strategy and methods shown in the illustration example can be analogously adopted and applied for other diseases preventions. The proposed strategy for a target group/community in a population provides a way to translate and apply epidemiological study results to clinical disease prevention practice.

First-Principles Study of Electronic Structure and Optical Properties of Silicon/Carbon Nanotube

A supercell of a nanotube formed by a carbon nanotube (CNT) and a silicon nanotube (SiNT) is established. The electronic structure and optical properties are implemented through the first-principles method based on the density functional theory (DFT) with the generalized gradient approximation (GGA). The calculated results show that (6, 6) - (6, 6) silicon/carbon nanotubes (Si/CNTs) presented a direct band gap of 0.093 eV, (4, 4) - (6, 6) silicon/carbon nanotubes presented a direct band gap of 0.563 eV. The top of valence band was fundamentally determined by the Si-3p states and C-2p states, and the bottom of conduction band was primarily occupied by the C-2p states and Si-3p states in the Si/CNTs. It was found that (6, 6) - (6, 6) Si/CNTs have smaller energy band gap and better conductivity. Besides, Si/CNTs have satisfactory absorption characteristics and luminous efficiency in ultraviolet band.

Risk Factors and Prediction of Stroke in a Population with High Prevalence of Diabetes: The Strong Heart Study

Background and Objective: American Indians have a high prevalence of diabetes and higher incidence of stroke than that of whites and blacks in the U.S. Stroke risk prediction models based on data from American Indians would be of clinical and public health value. Methods and Results: A total of 3483 (2043 women) Strong Heart Study participants free of stroke at baseline were followed from 1989 to 2010 for incident stroke. Overall, 297 stroke cases (179 women) were identified. Cox models with stroke-free time and risk factors recorded at baseline were used to develop stroke risk prediction models. Assessment of the developed stroke risk prediction models regarding discrimination and calibration was performed by an analogous C-statistic (C) and a version of the Hosmer-Lemeshow statistic (HL), respectively, and validated internally through use of Bootstrapping methods. Results: Age, smoking status, alcohol consumption, waist circumference, hypertension status, antihypertensive therapy, fasting plasma glucose, diabetes medications, high/low density lipoproteins, urinary albumin/creatinine ratio, history of coronary heart disease/heart failure, atrial fibrillation, or Left ventricular hypertrophy, and parental history of stroke were identified as the significant optimal risk factors for incident stroke. Discussion: The models produced a C = 0.761 and HL = 4.668 (p = 0.792) for women, and a C = 0.765 and HL = 9.171 (p = 0.328) for men, showing good discrimination and calibration. Conclusions: Our stroke risk prediction models provide a mechanism for stroke risk assessment designed for American Indians. The models may be also useful to other populations with high prevalence of obesity and/or diabetes for screening individuals for risk of incident stroke and designing prevention programs.

Experimental Investigation on Vibration Reduction Performance of Fiber Metal Laminate Beams with MRE Core

The vibration reduction characteristics of composite beams filled with magnetorheological elastomer core are studied experimentally.The fiber metal laminates with magnetorheological elastomers core is self-designed and prepared.Internal magnetic field is applied to the beam to explore its action of damping vibration performance under the magnetic field for the first time.The composite elements test system with controllable magnetic field intensity is designed and the function of each part is introduced.Then,a set of reasonable and standard vibration test flow of this type of composite beam under different magnetic field intensity is clarified,and the practical test is conducted.It has been found that the composite beam has excellent damping performance with the first 4 damping ratios being greater than 10%.Moreover,after the magnetic field is applied,its damping results can be further improved to meet the active control purpose.

The variation of DOM during long distance water transport by the China South to North Water Diversion Scheme and impact on drinking water treatment

In this study,samples were taken from three locations,upstream to downstream,along the central route project of the China South to North Water Diversion(SNWD)scheme in summer and winter.These were used to reveal the variations of dissolved organic matter(DOM)during the water transfer process,and the effects of these variations on drinking water treatment and disinfection by-products formation potential(DBPs-FP).The results showed that polysaccharides accumulate in summer and reduce in winter with flow distance,which has an important effect on the overall properties of DOM,as well as on the performance of coagulation,ultrafiltration,and the formation of DBPs.Humic substances,and their hydrophilic content,also increased in summer and decreased in winter with flow distance.In contrast,the concentration of small organic substances(MW≤1000 Da)increased in both summer and winter with flow distance,which affected both nanofiltration(NF)membrane fouling and DBPs-FP.The results provide a useful case study of spatial and temporal changes in raw water DOM during long distance water transfer and their impact on the treatment and quality of drinking water from the SNWD.

对流层臭氧卫星遥感反演综述

臭氧是地球大气中最重要的痕量气体之一,在气候变化和生态环境中均扮演着至关重要的角色。对流层臭氧作为光化学烟雾的重要成分之一,其浓度变化与人类活动息息相关。基于卫星遥感技术监测对流层臭氧浓度可以帮助我们更好地发现和定量解释对流层臭氧在不同季节、不同时刻以及不同区域的变化特征,探讨臭氧在对流层中的成因机制。随着卫星遥感技术的全面发展,臭氧遥感产品(例如臭氧总量、廓线等)无论在产品精度或是时空分辨率方面均取得了显著进步,然而,由于受较弱卫星信号与复杂下垫面的影响,对流层臭氧遥感产品精度仍无法满足目前对流层大气成分的精细化科学应用研究。主要围绕对流层臭氧卫星遥感,回顾和分析了臭氧卫星遥感载荷的发展历程和现状,结果表明国内外已基于不同谱段(紫外—可见光、热红外和太赫兹)实现了全球及区域臭氧的时空分布探测;讨论了基于不同技术遥感反演算法(直接与间接反演、多波段联合反演、天底—临边协同反演、基于机器学习技术的创新算法等)的特点及适用性,分析表明算法精度的提升包括从复杂大气背景下的辐射传输模拟、基于地面观测的先验信息优化以及仪器定标与信噪比等多方面的工作;展望了卫星遥感在全球和区域尺度提供可靠对流层臭氧观测数据的应用前景,为对流层臭氧污染的形成机理、人类活动与气候变化如何影响对流层臭氧浓度变化等方面的研究提供关键数据支撑。

Visible light promoted aerobic selective photo-oxidation of cyclohexene on LaCo_(x)Cu_(1−x)O_(3) catalyst

Heterogeneously catalyzed liquid oxidation of olefins with O_(2) provides an alternative way for synthesizing high-value added chemicals.Herein,we report a straightforward urea-redox and sol-gel process for synthesizing LaCo_(x)Cu_(1−x)O_(3) for aerobic photooxidation of cyclohexene.Our research highlights a marked increase in the proportions of Co^(2+) and Cu+species in a low chemical state,as well as enhanced visible light absorption through this method.Mechanistic investigations suggest that the catalytic process,particularly with LaCo_(0.7)Cu_(0.3)O_(3),involves a radical pathway mediated by reactive oxygen species.The presence of Cu+/Co^(2+) species and surface oxygen vacancies is proposed to boost O_(2) adsorption and activation on the catalyst,facilitating the formation of 2-cyclohexene-1-hydroperoxides.Furthermore,Cu^(2+)/Co^(3+) species are thought to aid in generating cyclohexenederived radical species.The efficient aerobic oxidation of cyclohexene on LaCo_(0.7)Cu_(0.3)O_(3) catalyst relies on the formation of reactive oxygen species and carbon radicals,facilitated by its strong visible light illumination.It achieves a cyclohexene conversion of 89.4% and selectivity to cyclohex-2-ene-1-one of 72.2%,along with stable recyclability after six reuses.The creation of nano-structured LaCo_(x)Cu_(1−x)O_(3) through the urea-redox and sol-gel process offers a promising avenue for the development of highly efficient catalysts for the aerobic photo-oxidation of cyclohexene to cyclohex-2-ene-1-one in the future.

Can sub-GeV dark matter coherently scatter on the electrons in the atom?

A novel detection of sub-GeV dark matter is proposed in the paper.The electron cloud is boosted by the dark matter and emits an electron when it is dragged back by the heavy nucleus,namely the coherent scattering of the electron cloud of the atom.The survey in the x-ray diffraction shows that the atomic form factors are much more complex than the naive consideration.The results of the relativistic Hartree-Fock(RHF)method give non-trivial shapes of the atoms.The detailed calculation of the recoil of the electron cloud,the kinetics,the fiducial cross section and the corresponding calculation of detection rate are given analytically.The numerical results show that the limits of the RHF form factors are much more stringent than the recoil of a single electron,almost 4 orders stronger,and also give tight limitations compared to the Migdal effect below about several hundred MeV.The physical picture and the corresponding results are promising and need further exploration.

Atomically dispersed Au_1 catalyst towards efficient electrochemical synthesis of ammonia

Tremendous efforts have been devoted to explore energy-efficient strategies of ammonia synthesis to replace Haber-Bosch process which accounts for 1.4% of the annual energy consumption. In this study, atomically dispersed Au_1 catalyst is synthesized and applied in electrochemical synthesis of ammonia under ambient conditions. A high NH＋4 Faradaic efficiency of 11.1 % achieved by our Au_1 catalyst surpasses most of reported catalysts under comparable conditions. Benefiting from efficient atom utilization, an NH＋4 yield rate of 1,305 μg h-1 mg-1Au has been reached, which is roughly 22.5 times as high as that by sup- ported Au nanoparticles. We also demonstrate that by employing our Au_1 catalyst, NH＋4 can be electro- chemically produced directly from N_2 and H_2 with an energy utilization rate of 4.02 mmol kJ-1. Our study provides a possibility of replacing the Haber-Bosch process with environmentally benign and energy-efficient electrochemical strategies.

A hierarchical heterostructure of CdS QDs confined on 3D ZnIn_(2)S_(4) with boosted charge transfer for photocatalytic CO_(2) reduction

Metal sulfide based materials as photocatalysts for energy conversion are essential to produce value-added chemical fuels,but their intrinsically slow carrier dynamics and low activity are yet to be resolved.Herein,we developed a unique heterogeneously nanostructured ZnIn_(2)S_(4)-CdS heterostructure that involves zero-dimensional(0D)CdS quantum dots uniformly confined on three-dimensional(3D)ZnIn_(2)S_(4)nanoflowers,which achieves an excellent catalytic performance of CO_(2) photoconversion under visible-light irradiation.The obtained hierarchical heterostructure can significantly enhance the light harvesting,shorten the migration distance of carriers,and obviously accelerate the transport of electrons.As evidenced by the ultrafast transient absorption spectroscopy,the formed interface can effectively facilitate charge separation and transport.This work opens up a new avenue to carefully design the elaborate heterostructures for achieving optimal charge separation efficiency by lowering interfacial kinetic barriers and energy losses at the interface.

Stable interphase chemistry of textured Zn anode for rechargeable aqueous batteries

Despite the advances of aqueous zinc(Zn)batteries as sustainable energy storage systems,their practical application remains challenging due to the issues of spontaneous corrosion and dendritic deposits at the Zn metal anode.In this work,conformal growth of zinc hydroxide sulfate(ZHS)with dominating(001)facet was realized on(002)plane-dominated Zn metal foil fabricated through a facile thermal annealing process.The ZHS possessed high Zn^(2+)conductivity(16.9 mS cm^(-1))and low electronic conductivity(1.28×10^(4)Ωcm),and acted as a heterogeneous and robust solid electrolyte interface(SEI)layer on metallic Zn electrode,which regulated the electrochemical Zn plating behavior and suppressed side reactions simultaneously.Moreover,low self-diffusion barrier along the(002)plane promoted the 2D diffusion and horizontal electrochemical plating of metallic Zn for(002)-textured Zn electrode.Consequently,the as-achieved Zn electrode exhibited remarkable cycling stability over 7000 cycles at 2 mA cm^(-2)and 0.5 mAh cm^(-2)with a low overpotential of 25 mV in symmetric cells.Pairing with a MnO_(2)cathode,the as-achieved Zn electrode achieved stable cell cycling with 92.7%capacity retention after 1000 cycles at 10 C with a remarkable average Coulombic efficiency of 99.9%.