Photothermal catalytic C-C coupling to ethylene from CO_(2) with high efficiency by synergistic cooperation of oxygen vacancy and half-metallic WTe_(2)

Photothermal catalytic CO_(2) conversion provides an effective solution targeting carbon neutrality by synergistic utilization of photon and heat.However,the C-C coupling initiated by photothermal catalysis is still a big challenge.Herein,a three-dimensional(3D)hierarchical W_(18)O_(49)/WTe_(2) hollow nanosphere is constructed through in-situ embodying of oxygen vacancy and tellurium on the scaffold of WO_(3).The light absorption towards near-infrared spectral region and CO_(2) adsorption are enhanced by the formation of half-metal WTe_(2) and the unique hierarchical hollow architecture.Combining with the generation of oxygen vacancy with strengthened CO_(2) capture,the photothermal effect on the samples can be sufficiently exploited for activating the CO_(2) molecules.In particular,the close contact between W_(18)O_(49)and WTe_(2) largely promotes the photoinduced charge separation and mass transfer,and thus the~*CHO intermediate formation and fixedness are facilitated.As a result,the C-C coupling can be evoked between tungsten and tellurium atoms on WTe_(2).The ethylene production by optimized W_(18)O_(49)/WTe_(2) reaches 147.6μmol g^(-1)with the selectivity of 80%.The in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)calculations are performed to unveil the presence and significance of aldehyde intermediate groups in C-C coupling.The half-metallic WTe_(2) cocatalyst proposes a new approach for efficient CO_(2) conversion with solar energy,and may especially create a new platform for the generation of multi-carbon products.

Finite-Time H∞ Control of Switched Nonlinear Systems under State-Dependent Switching

This paper investigates the finite-time H∞ control problem of switched nonlinear systems via state-dependent switching and state feedback control. Unlike the existing approach based on time-dependent switching strategy, in which the switching instants must be given in advance, the state-dependent switching strategy is used to design switching signals. Based on multiple Lyapunov-like functions method, several criteria for switched nonlinear systems to be finite-time H∞ control are derived. Finally, a numerical example with simulation results is provided to show the validity of the conclusions.

具有高效激子解离和明确反应位点的Tröger碱基三维多孔芳基有机骨架及其光催化近单一选择性CO_(2)转化

植物光合作用是吸收光能,把CO_(2)和水转化成富能有机物,同时释放氧气的过程.受此启发,利用太阳光将CO_(2)转化为碳氢燃料的人工碳中和技术引起了广泛关注.人工光合作用能否成功实施取决于光催化剂的设计制备.无机半导体已被广泛研究用于CO_(2)光还原反应(CO_(2)PRR),但其存在金属氧化物的带隙较宽且难以调节、导致光吸收较差和金属硫化物的光腐蚀问题严重等明显的缺点.此外,高载流子复合率和低比表面积会影响光催化效率,从而限制光子利用.因此,基于有机聚合物的无金属催化剂因其突出的可设计调控性而被提出,其中,具有超高比表面积的材料—多孔芳香骨架(PAFs)聚合物是研究热点之一,但是传统PAFs材料多为二维平面结构,用于光催化的无金属三维PAFs报道较少.此外,具有孤对电子的杂原子(N,B,F)修饰的材料可以与CO_(2)分子产生特定的偶极-四极相互作用,提高材料对CO_(2)的吸附和活化能力,是提升有机聚合物光催化剂性能的有效策略.本文采用Sonogashira-Hagihara偶联将具有不同共轭程度的芳香炔烃(2,2’,7,7‘-四乙炔基-9,9’-螺二芴,SPF-T;四(4-乙炔基苯基)甲烷,TEPM-T;1,1,2,2-四(4-乙炔基苯基)乙烯,TEPE-T)与含有N杂原子的Tröger碱聚合制备了具有三维结构的多孔芳香骨架聚合物X-TB-PAFs(X=TEPE,TEPM,SPF).通过X-射线衍射、红外光谱、13C核磁共振(NMR)以及1H NMR等表征手段验证了目标聚合物的成功合成.通过紫外-可见光谱和Mott-Schottky曲线测试研究了聚合物具体的能带结构,发现三种PAFs聚合物材料在热力学上同时满足光催化CO_(2)-CO的还原反应条件(Eθ=-0.51 Vvs.NHE,pH=7)和光催化H2O-O_(2)的氧化条件(Eθ=0.82 V vs.NHE,pH=7).V形骨架结构的Tröger碱(TB)单元和芳炔的结合赋予了聚合物刚性稳定的孔隙率以及较高的比表面积,材料中的多孔结构可以使其暴露更多的活性位点,三维框架结构为反应物接近活性位点提供了丰富的开放式空腔,这些都有利于材料对CO_(2)的捕获,增强催化剂对CO_(2)的吸附/活化能力.此外,炔基充当连接通道还可以增强体系的载流子迁移率,提升材料的光催化性能.密度泛函理论计算和光电性能测试结果表明,TB官能团引入带来的分子内极化和电子陷阱位点的优势,其与三维共轭网络结构一起协同调节了光生载流子的分离和反应位点分布.三种三维PAFs中,基于全共轭结构TEPE-T的TEPE-TB-PAF表现出最高效的光生载流子传输与分离效率,在没有助催化剂和牺牲剂的情况下表现出较好的光催化CO产率(194.50μmolg^(-1)h^(-1))和近乎单一的选择性(99.74%).全共轭TEPE-T的引入和分子内极化的存在可以促进框架内载流子的分离和迁移.材料中的电偶极矩(从负电荷到正电荷)指向TB中含有叔氮官能团的桥接位点,使其成为明确的催化反应位点.光电流和阻抗测试结果表明,TEPE-TB-PAF具有更好的电子-空穴分离能力和更小的电荷迁移位阻.三维框架构建产生的多重散射截面可以促进材料中的光子吸收,从而提高其光催化性能.理论计算和原位漫反射傅立叶变换红外光谱结果表明,材料中CO解吸的低能垒和*CHO形成的高能垒是TEPE-TB-PAF高CO产率和选择性的根本机制.综上,本文为多功能高效有机聚合物光催化剂的合成提供了有效途径,并为同时改善光催化剂的转化率和选择性提供了借鉴.

3D hierarchical architecture collaborating with 2D/2D interface interaction in Ni Al-LDH/Ti_(3)C_(2) nanocomposite for efficient and selective photoconversion of CO_(2)

Photocatalytic conversion of CO_(2)into a special chemical fuel with high yield and selectivity is still a major challenge.Herein,a 3 D hierarchical Ni Al-LDH/Ti_(3)C_(2)MXene(LDH/TC)nanocomposite is constructed through in situ loading of Ti_(3)C_(2)nanosheets on the Ni Al-LDH scaffold during the hydrothermal process.The formation of a uniform and well-defined 2 D/2 D heterogeneous interface can be realized by optimizing the ratio of Ti_(3)C_(2)and the precursors for Ni Al-LDH.The 3 D hierarchical scaffold with high specific surface area contributes to the favourable photon adsorption and utilization.The intimate contact between Ti_(3)C_(2)and Ni Al-LDH with numerous interfaces effectively promotes the separation of the photoinduced electron-hole pairs in Ni Al-LDH.Together with the highly exposed oxidation-reduction active sites and the enhanced CO_(2)capture and activation.The maximum photocatalytic CO production rate on Ni AlLDH/Ti_(3)C_(2)reaches 11.82 lmol g^(-1)h^(-1)with 92%selectivity and superior stability.This work provides an effective approach for the development of an ideal photocatalyst by collaborative utilization of materials with different dimensionalities.

Conflicts in Defining Data Ownership in China’s Digital Transformation and the Regulatory Path

China is aggressively pursuing digital transformation,and data,alike labor,technology,capital,and knowledge,has become as a crucial factor of production.Digital transformation is accelerating the emergence of a data-intensive society,and the ensuing difficulties of balancing freedom and responsibility,openness and security,as well as free sharing and legal regulation are posing new challenges to national and social governance.Among these challenges,defining data ownership,the social disorder and anomie brought about by the unclear definition of data ownership,and data ownership regulatory path are new propositions that need to be urgently addressed in this data-intensive society.This paper systematically explains the theoretical meaning and practical value of data ownership through a literature review on the analysis of domestic and foreign scholars as well as research think tanks,compares the differences and inherent conflicts between the definition of data ownership by the government,enterprises,and society in China,thoroughly compares the definition standards of the European Union,the United States,and Japan,and on this basis,discusses the formation of a definition of data ownership that meets the requirements of China’s digital transformation.

不同加工方式形成的波形表面弹塑性接触行为表征

不同的加工方法对表面接触行为产生了影响,涉及表面周期性、随机性和屈服应力等方面.本研究采用实验和数值方法,系统地研究了铣削、线切割电火花加工和滚花三种加工方法产生的表面凸起体在不同载荷条件下的接触行为.采用分段辅助的数字图像相关技术结合基于位移的弹塑性判据方法,直接观察了弹塑性边界.对不同加工方式形成的表面进行傅里叶变换,得到对应不同阶次的频率.对比评估了由不同阶次傅里叶频率生成的表面和原始表面的接触行为.全面讨论了接触过程中的接触面积、平均接触压力和塑性演变等参数。此外,还详细研究了在不同载荷条件下表面噪声对接触行为的影响.为了直观展示塑性扩展行为,本研究提出了基于平均接触压力和与每种加工方法形成的表面相关的干涉的塑性演变公式.此外,本文也研究了切向载荷和屈服应力对塑性扩展的影响。

Isolation and characterization of spike S2-specific monoclonal antibodies with reactivity to pan-coronaviruses

Dear Editor,Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),theseventh coronavirus known to jump from intermediate hosts to humans,has resulted in a worldwide pandemic and caused immense economicdamage(Tan et al.,2020;Zhu et al.,2020).It is believed that coronavirus spillover may occur again in the future.Human exposure to a bat coro-navirus has been serologically confimed in a rural area of China,indi-cating that the coronavirus spillover occurred,although the origin andfrequency of spillovers are unclear(Wang et al.,2018).

Pharmacological inhibition of BAP1 recruits HERC2 to competitively dissociate BRCA1-BARD1, suppresses DNA repair and sensitizes CRC to radiotherapy

Radiotherapy is widely used in the management of advanced colorectal cancer(CRC).However,the clinical efficacy is limited by the safe irradiated dose.Sensitizing tumor cells to radiotherapy via interrupting DNA repair is a promising approach to conquering the limitation.The BRCA1-BARD1 complex has been demonstrated to play a critical role in homologous recombination(HR)DSB repair,and its functions may be affected by HERC2 or BAP1.Accumulated evidence illustrates that the ubiquitination-deubiquitination balance is involved in these processes;however,the precise mechanism for the cross-talk among these proteins in HR repair following radiation hasn’t been defined.Through activity-based profiling,we identified PT33 as an active entity for HR repair suppression.Subsequently,we revealed that BAP1 serves as a novel molecular target of PT33 via a CRISPR-based deubiquitinase screen.Mechanistically,pharmacological covalent inhibition of BAP1 with PT33 recruits HERC2 to compete with BARD1 for BRCA1 interaction,interrupting HR repair.Consequently,PT33 treatment can substantially enhance the sensitivity of CRC cells to radiotherapy in vitro and in vivo.Overall,these findings provide a mechanistic basis for PT33-induced HR suppression and may guide an effective strategy to improve therapeutic gain.

Development and validation of an m6A RNA methylation regulatorbased signature for the prediction of prognosis and immunotherapy in cutaneous melanoma

To the Editor:The incidence of cutaneous melanoma,which has an extremely poor prognosis and is responsible for the majority of skin cancer-related deaths,has been increasing rapidly.^([1])m6A(N6-methyladenosine),which is methylated at the N6 position of adenosine,is the most prominent modification in messenger ribonucleic acid(mRNAs)and long non-coding ribonucleic acid(RNAs)in eukaryotic cells and modifies the RNA’s stability,translocation,and RNA splicing and translation into protein.Multiple studies have revealed that tumorigenesis is cogently associated with m6A RNA methylation.^([2])However,the relationship between m6A methylation regulators and the prognosis,as well as the risk of immune evasion of cutaneous melanoma(CM),remains unknown.Our study aims to identify the prognostic value of m6A regulators in CM.

3D dahlia-like NiAl-LDH/CdS heterosystem coordinating with 2D/2D interface for efficient and selective conversion of CO_(2)

Developing photocatalyst with high activity,superior stability and prominent selectivity for CO_(2)conversion is of great importance for the target of carbon neutralization.Herein,3 D dahlia-like NiAl-LDH/CdS heterosystem is developed through in-situ decoration of exfoliated CdS nanosheets on the scaffold of NiAl-LDH and the on-spot self-assembly.The formation of a hierarchical architecture collaborating with well-defined 2 D/2 D interfacial interaction is constructed by optimizing the ratio of CdS integrated in the formation of the heterojunction.The light-harvesting capacity of NiAl-LDH/CdS is improved by this unique scaffold,and the charge transfer between NiAl-LDH and CdS is effectively facilitated by virtue of the unique 2 D/2 D interface.As a result,the 3 D hierarchical NiAl-LDH/CdS heterosystem presents 12.45μmol g^(-1)h^(-1)of CO production(3.3 and 1.6 folds of pristine NiAl-LDH and CdS) with 96% selectivity and superior stability.This 3 D hierarchical design collaborating with 2 D/2 D interfacial interaction provides a new avenue to develop ideal catalysts for artificial photosynthesis.

Changes in soil faunal density and microbial community under altered litter input in forests and grasslands

Root and foliar litter inputs are the primary sources of carbon and nutrients for soil fauna and microorganisms,yet we still lack a quantitative assessment to evaluate the effects of root and foliar litter on various groups of soil organisms across terrestrial ecosystems.Here,we compiled 978 paired observations from 68 experimental sites to assess the directions and magnitudes of adding and removing foliar and root litter on the soil faunal density and microbial biomass that was evaluated by phospholipid fatty acids(PLFAs)across forests and grasslands worldwide.We found that litter addition had only a marginal effect on soil faunal density but significantly increased the soil total microbial-,fungal-and bacterial-PLFAs by 13%,14%,and 10%,respectively,across ecosystems,suggesting that the soil microbial community is more sensitive to carbon source addition than soil fauna,particularly in soils with low carbon to nitrogen ratios.In contrast,removing litter significantly decreased the soil faunal density by 17%but had few effects on soil microorganisms.Compared with foliar litter,root litter input had a more positive effect on the development of soil fungal taxa.The effect of both litter addition and removal on soil faunal density and microbial biomass did not differ between humid and arid regions,but a greater influence was observed in grasslands than in forests for soil microbial community.Our results highlight that the increasing litter production under a global greening scenario would stimulate microbial activity in grasslands more than in forests,and this stimulation would be greater for soil microbes than soil fauna.

Gate-tunable linear magnetoresistance in molybdenum disulfide field-effect transistors with graphene insertion layer

Molybdenum disulfide (MoS2) holds great promise as atomically thin two-dimensional (2D) semiconductor for future electronics and opto-electronics. In this report, we study the magnetoresistance (MR) of MoS2 field-effect transistors (FETs) with graphene insertion layer at the contact interface. Owing to the unique device structure and high-quality contact interface, a gate-tunable linear MR up to 67% is observed at 2 K. By comparing with the MRs of graphene FETs and MoS2 FETs with conventional metal contact, it is found that this unusual MR is most likely to be originated from the contact interfaces between graphene and MoS2, and can be explained by the classical linear MR model caused by spatial fluctuation of carrier mobility. Our study demonstrates large MR responses in MoS2-based systems through heterojunction design, shedding lights for the future magneto-electronics and van der Waals heterostructures.

白蚁活动对中亚热带次生林和人工林的危害差异

中亚热带地区是中国南方重要的木材生产基地,大量的地带性常绿阔叶林被转换成以杉木(Cunninghamia lanceolata)为代表的人工林。白蚁是森林中最主要的社会性昆虫之一,其取食行为既对森林类型转换后林中的树木产生危害,也对林间枯枝落叶的分解具有十分重要的意义,但对二者缺乏统一的认识。本文以中亚热带典型的米槠(Castanopsis carlesii)次生林、米槠人工林和杉木人工林为研究对象,调查了不同林分白蚁的活动特点及其范围。结果表明,米槠次生林与杉木、米槠人工林中均普遍存在白蚁取食现象,但白蚁对次生林的取食高度和面积均远低于人工林。白蚁对生物多样性较高的米槠次生林树干韧皮部的取食面积仅分别为米槠人工林的1.65%和杉木人工林的0.59‰,取食高度的11.1%和1.2%。同时,白蚁对杉木韧皮部的取食显著大于米槠,对杉木的取食面积和高度分别是米槠的27.7倍和9.2倍。每隔0.5 m为一个统计区间,白蚁对杉木树干2 m以下韧皮部取食面积比例由低往高为4:3:2:1,对米槠1 m以下高度部位的取食面积比为99:1。此外,白蚁对次生林地表覆盖的凋落枝和凋落叶的平均取食面积分别为51.7%和46.1%,而人工林对应均值分别为17.5%和29.4%,均表现为次生林高于人工林。这些结果表明白蚁对生物多样性较高的次生林危害小于杉木人工林,且在人工林中可见危害主要体现在白蚁对韧皮部的取食,在次生林主要体现在白蚁对凋落物残体的分解作用,这为区域森林经营管理提供理论支撑。

Molecular rotors with designed polar rotating groups possess mechanics-controllable wide-range rotational speed

Molecular rotors with controllable functions are promising for molecular machines and electronic devices.Especially,fast rotation in molecular rotor enables switchable molecular conformations and charge transport states for electronic applications.However,the key to molecular rotor-based electronic devices comes down to a trade-off between fast rotational speed and thermal stability.Fast rotation in molecular rotor requires a small energy barrier height,which disables its controllability under thermal excitation at room temperature.

Fixed points of smoothing transformation in random environment

At each time n∈N,let Y^(n)(ξ)=(y^(n)_(1)(ξ),y^(n)_(2)(ξ),…)be a random sequence of non-negative numbers that are ultimately zero in a random environmentξ=(ξ_(n))n∈N.The existence and uniqueness of the non-negative fixed points of the associated smoothing transformation in random environment are considered.These fixed points are solutions to the distributional equation for a.e.ξ,Z(ξ)=dΣ_(i∈N_(+))y^(0)_(i)(ξ)Z^(1)_(i)(ξ),where{Z^(1)_(i):i∈N_(+)}are random variables in random environment which satisfy that for any environmentξ,under P_(ξ),{Z^(1)_(i)(ξ):i∈N_(+)}are independent of each other and Y^(0)(ξ),and have the same conditional distribution P_(ξ)(Z^(1)_(i)(ξ)∈·)=P_(Tξ)(Z(Tξ)∈·),where T is the shift operator.This extends the classical results of J.D.Biggins[J.Appl.Probab.,1977,14:25-37]to the random environment case.As an application,the martingale convergence of the branching random walk in random environment is given as well.

Paper-based fluorescent devices for multifunctional assays:Biomarkers detection,inhibitors screening and chiral recognition

The development of a single analytical platform with different functions is highly desirable but remains a challenge at present.Here,a paper-based device based on fluorescent carbon dots(CDs)functionalized paper/MnO_(2)nanosheets(MnO_(2)NS)hybrid devices(PCD/NS)was proposed for single-device multi-function applications.MnO_(2)NS functioned as a fluorescence quencher of CDs and recognizer of H_(2)O_(2)released from the oxidase catalyzed system.Fluorescence recovery would occur after the decomposition of MnO_(2)NS induced by H_(2)O_(2),by which a simple and effective strategy could be developed for fluorescence monitoring multiplex biological events.Xanthine(XA)sensing,xanthine oxidase(XOD)inhibitors screening analysis and chiral recognition of glucose enantiomers were performed on PCD/NS to investigate the multifunctional application of the paper-based device.By means of PCD/NS,XA could be determined in the range of 0.1–40μmol/L with a low detection of limit of 0.06μmol/L.The IC_(50)value of allopurinol,the model inhibitor of XOD,was sensitively detected to be 7.4μmol/L.Glucose enantiomers were also recognized in terms of the specific fluorescence response to d-glucose.This work firstly presented a paper-based device capable of biomarkers detection,inhibitors screening and chiral recognition,which enlightened a promising strategy for the construction of multifunctional devices and hold the great potential application in clinical diagnosis and drug discovery.

Extremum of a time-inhomogeneous branching random walk

Consider a time-inhomogeneous branching random walk, generated by the point process Ln which composed by two independent parts: ‘branching’offspring Xn with the mean 1+B(1+n)−β for β∈(0,1) and ‘displacement’ ξn with a drift A(1+n)^(−2α) for α∈(0,1/2), where the ‘branching’ process is supercritical for B>0 but ‘asymptotically critical’ and the drift of the ‘displacement’ ξn is strictly positive or negative for |A|>0 but ‘asymptotically’ goes to zero as time goes to infinity. We find that the limit behavior of the minimal (or maximal) position of the branching random walk is sensitive to the ‘asymptotical’ parameter β and α.

Small bending, big curvature^(FA)

The classical"Cholodny-Went theory"predicted that directional stimuli trigger the redistribution of auxin,which governs the differential growth of plant organs through potent effects on cell expansion,thereby establishing an"auxin-then-growth"paradigm;this theory has been validated for both gravitropism and phototropism in plants(reviewed in Muthert et al.,2020).

Molecular mechanism of Verticillium dahliae-induced leaf senescence

Verticillium dahliae is a soil-borne hemibiotrophic fungus that affects a wide range of hosts,including important crops(such as cotton,tomato,potatoes,cauliflower,and sunflower)and the model plant Arabidopsis(Fradin and Thomma,2006).V.dahliae infections can result in significant crop losses as no effective fungicides are available at the moment.Upon infection,V.dahliae causes verticillium wilt,leaf chlorosis and cell death,and precocious senescence in host plants(Fradin and Thomma,2006).Leaf senescence is known to be regulated by developmental age,plant hormones(e.g.,ethylene),and a variety of environmental factors(Woo et al.,2019),but how V.dahliae induces leaf senescence in its host plants is not clear.

Spin relaxation induced by interfacial effects in GaN/Al_(0.25) Ga_(0.75) N heterostructures

Spin relaxation induced by the interfacial effects in GaN/Al_(0.25) Ga_(0.75) N heterostructures was carefully investigated using a photon-energy-dependent time-resolved Kerr rotation spectrum.The existence of the interfacial localized states with potential fluctuations at the GaN/AlGaN heterointerface leads to photoluminescence peaks showing blue and S-shaped shifts owing to the excitation power and temperature,respectively.Photoexcited electrons in the localized states show a spin relaxation time longer than 1 ns because of the suppression of the D’yakonov-Perel’(DP)scattering,while the spin relaxation time of free electrons was approximately only 10 ps because of the giant Rashba spin-orbit coupling induced by the interfacial polarization field under the framework of the DP scattering mechanism.Furthermore,it is found that the high electron mobility at the heterointerface results in a long spin diffusion length of 300 nm at high temperatures,which is promising for the development of GaN-based spintronic devices.