氧化还原对Lindqvist型多金属氧簇复合物自组装的动态调控

自组装的动态调控对材料科学的发展至关重要,它在智能材料和器件的开发中具有巨大的潜力。多金属氧簇是一类纳米尺度的无机功能簇,尤其是当它被有机组分共价修饰或者非共价修饰之后,已经发展成为超分子自组装中优异的构筑基元之一。多金属氧簇是典型的刺激响应功能团簇,光化学或电化学方法可将其还原为混合价态,即使经历了逐步的多电子氧化还原后多金属氧簇的结构仍保持不变。多金属氧簇独特的光致变色使其表现出不同的光物理性质,这激励着我们去开发基于多金属氧簇复合物的动态自组装。Lindqvist型六钼酸盐簇[Mo6O19]2-是负电荷数目最少的多金属氧簇之一,是构筑新颖组装结构的理想构筑基元。本文在乙腈溶剂中用十八烷基三甲基铵替换Lindqvist型多金属氧簇复合物(TBA)2[Mo6O19]的抗衡离子,通过简单的替换方法制备了一种单链表面活性剂包覆的多金属氧簇复合物(ODTA)2[Mo6O19]。通过核磁共振氢谱、红外光谱、热重分析和元素分析表征了多金属氧簇复合物的结构。复合物(ODTA)2[Mo6O19]在乙腈和异丙醇(体积比是4比1)中的溶液在经过交替的紫外光照和空气氧化后表现出了可逆的光致变色性质。复合物的溶液经紫外光照后由浅黄色快速变成蓝色。紫外可见吸收光谱在751 nm处出现的宽吸收带归属于MoV→MoVI的价间电荷转移跃迁,这表明还原态多金属氧簇的形成。经过空气氧化之后蓝色褪去。这种可逆的光致变色可以多次循环实现。扫描电镜、透射电镜和X射线衍射的测试证实了复合物在乙腈和异丙醇中形成了螺旋形貌的组装体。更有意义的是,复合物在光致变色的同时发生了从螺旋条带到球形组装体的形貌转变。光致变色过程中的形貌演变是从短螺旋条带经过海胆型聚集体变为球形组装体。最重要的是,经过空气氧化后螺旋组装体可以再次恢复,表明这是由氧化还原刺激驱动的可逆形貌转变。X射线光电子能谱和核磁共振氢谱的测试表明,氧化还原调控的可逆自组装是由无机簇与有机阳离子之间静电吸引力和无机簇之间静电排斥力的变化所驱动的。此研究结果将有助于更好地理解动态自组装的机理,并有助于推动先进智能材料的精准制备。

Surface latent heat flux anomalies preceding inland earthquakes in China

Using data from the National Center for Environmental Prediction(NCEP),the paper analyzed the surface latent heat flux(SLHF) variations for five inland earthquakes occurred in some lake area,moist area and arid area of China during recent years.We used the SLHF daily and monthly data to differentiate the global and seasonal variability from the transient local anomalies.The temporal scale of the observed variations is 1-2 months before and after the earthquakes,and spatial scale is about 10°×10°.The result suggests that the SLHFs adjacent the epicenters all are anomalous high value(>μ+2σ) 8-30 days before the shocks as compared with past several years of data.Different from the abnormal meteorologi-cal phenomenon,the distribution of the anomalies was isolated and local,which usually occurred in the epicenter and its adjacent area,or along the fault lines.The increase of SLHF was tightly related with the season which the earthquake occurs in;the maximal(125 W/m2,Pu'er earthquake) and minimal(25 W/m2,Gaize earthquake) anomalies were in summer and winter,respectively.The abundant surface water and groundwater in the epicenter and its adjacent region can provide necessary condition for the change of SLHF.To further confirm the reliability of SLHF anomaly,it is necessary to explore its physical mechanism in depth by more earthquake cases.

An Examination of the Predictability of Tropical Cyclone Genesis in High-Resolution Coupled Models with Dynamically Downscaled Coupled Data Assimilation Initialization

Predicting tropical cyclone(TC)genesis is of great societal importance but scientifically challenging.It requires fineresolution coupled models that properly represent air−sea interactions in the atmospheric responses to local warm sea surface temperatures and feedbacks,with aid from coherent coupled initialization.This study uses three sets of highresolution regional coupled models(RCMs)covering the Asia−Pacific(AP)region initialized with local observations and dynamically downscaled coupled data assimilation to evaluate the predictability of TC genesis in the West Pacific.The APRCMs consist of three sets of high-resolution configurations of the Weather Research and Forecasting−Regional Ocean Model System(WRF-ROMS):27-km WRF with 9-km ROMS,and 9-km WRF with 3-km ROMS.In this study,a 9-km WRF with 9-km ROMS coupled model system is also used in a case test for the predictability of TC genesis.Since the local sea surface temperatures and wind shear conditions that favor TC formation are better resolved,the enhanced-resolution coupled model tends to improve the predictability of TC genesis,which could be further improved by improving planetary boundary layer physics,thus resolving better air−sea and air−land interactions.

Two-step method to extract seismic microwave radiation anomaly:Case study of M_s8.0 Wenchuan earthquake

The satellite remote sensing has become a promising technique for detecting earthquake and fault activities.But it is still very difficult to exactly extract the earthquake anomaly from the complicated remote sensing information.This paper presented a two-step method to extract the seismic microwave radiation anomaly related with earthquake,which could eliminate the stable influence of geography,terrain,coversphere and seasons, as well as the random influence of weather.Furthermore the two-step method was applied to analyze the anomaly of Wenchuan earthquake based on the data of AMSR-E.Microwave radiation anomalies were effectively detected related to the main shock and aftershocks.The extracted microwave radiation variation showed general features of three-stage:the positive radiation anomaly appeared around the epicenter in the first stage,quiet variation in the second stage,and abnormal area gradually moved to the epicenter in the third stage.After the main shock the microwave radiation anomalies distributed along the Longmenshan faults,and the epicenters of aftershocks were coincident with the anomaly area in space.

Land Surface Displacement Geohazards Monitoring Using Multi-temporal InSAR Techniques

China has been affected by some of the world’s most serious geological disasters and experiences high economic damage every year.Geohazards occur not only in remote areas but also in highly populated cities.In the framework of the Dragon-432365 Project,this paper presents the main results and the major conclusions derived from an extensive exploitation of Sentinel-1,ALOS-2(Advanced Land Observing Satellite 2),GF-3(Gao Fen Satellite 3),and latest launched SAR(Synthetic Aperture Radar),together with methods that allow the evaluation of their importance for various geohazards.Therefore,in the scope of this project,the great benefits of recent remote sensing data(wide spatial and temporal coverage)that allow a detailed reconstruction of past displacement events and to monitor currently occurring phenomena are exploited to study different areas and geohazards problems,including:surface deformation of mountain slopes;identification and monitoring of ground movements and subsidence;landslides;ground fissure;and building inclination studies.Suspicious movements detected in the different study areas were cross validated with different SAR sensors and truth data.

Decadal Indian Ocean Dipolar Variability and Its Relationship with the Tropical Pacific

A robust decadal Indian Ocean dipolar variability(DIOD) is identified in observations and found to be related to tropical Pacific decadal variability(TPDV).A Pacific Ocean–global atmosphere(POGA) experiment,with fixed radiative forcing,is conducted to evaluate the DIOD variability and its relationship with the TPDV.In this experiment,the sea surface temperature anomalies are restored to observations over the tropical Pacific,but left as interactive with the atmosphere elsewhere.The TPDV-forced DIOD,represented as the ensemble mean of 10 simulations in POGA,accounts for one third of the total variance.The forced DIOD is triggered by anomalous Walker circulation in response to the TPDV and develops following Bjerknes feedback.Thermocline anomalies do not exhibit a propagating signal,indicating an absence of oceanic planetary wave adjustment in the subtropical Indian Ocean.The DIOD–TPDV correlation differs among the 10 simulations,with a low correlation corresponding to a strong internal DIOD independent of the TPDV.The variance of this internal DIOD depends on the background state in the Indian Ocean,modulated by the thermocline depth off Sumatra/Java.

In situ crosslinking of polyoxometalate-polymer nanocomposites for robust high-temperature proton exchange membranes

The most practical high-temperature proton exchange membranes(PEMs) are phosphoric acid(PA)-doped polymer electrolytes. However, due to the plasticizing effect of PA, it is a challenge to address the trade-off between the proton conductivity and the mechanical performance of these materials. Here,we report an effective strategy to fabricate robust high-temperature PEMs based on the in situ electrostatic crosslinking of polyoxometalates and polymers. A comb copolymer poly(ether-ether-ketone)-grafted-poly(2-ethyl-2-oxazoline)(PGE) with transformable side chains was synthesized and complexed with H_(3)PW_(12)O_(40)(PW) by electrostatic self-assembly, forming PGE/PW nanocomposite membranes with bicontinuous nanostructures. After a subsequent PA-treatment of these membranes, high-temperature PEMs of PGE/PW/PA ternary nanocomposites were obtained, in which the in situ electrostatic crosslinking effect between PW and PGE side chains was generated in the hydrophilic domains of the bicontinuous structures. The microphase separation structure and the electrostatic crosslinking feature endow the PGE/PW/PA membranes with excellent anhydrous proton conductive ability while retaining high mechanical performance. The membranes show a high proton conductivity of 42.5 m S/cm at 150 ℃ and a high tensile strength of 13 MPa. Our strategy can pave a new route based on electrostatic control to design nanostructured polymer electrolytes.

Space-associated domain adaptation for three-dimensional mineral prospectivity modeling

Geographical information systems(GIS)are essential tools for mineral prospectivity modeling(MPM).Three-dimensional(3D)MPM is able to learn the association between geological evidence and mineralization in shallow zones and thereby build a prospectivity model for deep zones,making it a desirable technique to target deep-seated orebodies.However,existing 3D MPM methods directly generalize the model learned in shallow zones to the deep zones without attention to model transferability caused by the different metallogenic mechanisms between the two zones.In this study,we aim to robustly transfer the prospectivity model learned from shallow zones to deep zones.We cast the 3D MPM as a domain adaptation problem,which is an important realm of transfer learning.Because the metallogenic mechanism can be closely associated with spatial locations,we specifically focus on domain adaption concerning the spatial locations that are ignored by conventional domain adaptation methods.To measure the spatial-associated domain discrepancy,we propose a novel spatial-associated maximum mean discrepancy(SAMMD),which compares the joint distributions of features and spatial locations across domains.Based on the SAMMD criterion,a deep neural network,referred to as the spatial-associated domain adaptation network,is devised to learn cross-domain but mineralization-indicative features for building prospectivity model that is transferable to deep zones.A case study of the world-class Sanshandao gold deposit,in eastern China,was carried out to validate the effectiveness of the proposed methods.The results show that compared with other leading MPM methods and other domain adaption variants,the proposed method has superior prediction accuracy and targeting efficiency,demonstrating the effectiveness and robustness of the proposed method in targeting deep-seated orebodies in areas with different metallogenic mechanisms and no labeled data.

“透明海洋”立体观测网构建

1全球海洋观测网络构建状况浅析海洋是人类生存发展的重要物质基础,是高质量发展的战略要地.随着陆地资源减少甚至枯竭,海洋已经成为拓展人类生存与发展空间的主要领域,世界各国都把维护国家海洋权益、发展海洋经济、保护海洋环境、开发海洋资源列为重大发展战略.海洋观测是认识海洋的基本手段,是海洋经济开发、环境保护和权益维护的基础.实施“透明海洋”战略,加强海洋观测技术装备研发,建设海洋综合立体观测体系,已经成为我国海洋科技创新的一个重要方向[1].

Complete three-dimensional coseismic displacements due to the 2021 Maduo earthquake in Qinghai Province,China from Sentinel-1 and ALOS-2 SAR images

On 22 nd May 2021(local time),an earthquake of M_(s)7.4 struck Maduo county in Qinghai Province,China.This was the largest earthquake in China since the 2008 Wenchuan earthquake.In this study,ascending/descending Sentinel-1 and advanced land observation satellite-2(ALOS-2)synthetic aperture radar(SAR)images were used to derive the three-dimensional(3-D)coseismic displacements of this earthquake.We used the differential interferometric SAR(In SAR,DIn SAR),pixel offset-tracking(POT),multiple aperture In SAR(MAI),and burst overlap interferometry(BOI)methods to derive the displacement observations along the line-of-sight(LOS)and azimuth directions.To accurately mitigate the effect of ionospheric delay on the ALOS-2 DIn SAR observations,a polynomial fitting method was proposed to optimize range-spectrum-split-derived ionospheric phases.In addition,the 3-D displacement field was obtained by a strain model and variance component estimation(SM-VCE)method based on the high-quality SAR displacement observations.Results indicated that a left-lateral fault slip with the largest horizontal displacement of up to 2.4 m dominated this earthquake,and the small-magnitude vertical displacement with an alternating uplift/subsidence pattern along the fault trace was more concentrated in the near-fault regions.Comparison with the global navigation satellite system data indicated that the SM-VCE method can significantly improve the accuracy of the displacements compared to the classical weighted least squares method,and the incorporation of the BOI displacements can substantially benefit the accuracy of north-south displacement.In addition to the displacements,three coseismic strain invariants calculated based on the strain model parameters were also investigated.It was found that the eastern and western parts of the faults suffered more significant strains compared with the epicenter region.

一个用动力降尺度耦合资料同化作初始化的亚洲太平洋区域耦合预报系统

基于WRF和ROMS,结合局地动力降尺度的耦合资料同化,研发了一个涵盖亚洲太平洋地区(38°E^180°,20°S^60°N)(AP-RCP)的区域耦合预报系统.该系统包括两个不同分辨率的耦合模式,分别是27 km的WRF与9 km的ROMS耦合,以及9 km的WRF与3 km的ROMS耦合.该系统在青岛海洋科学与技术国家(试点)实验室每天准业务化运行,制作18天的区域海洋和大气环境预报.本文对该系统的延伸期预报技巧进行了初步评估,结果表明,由于高分辨率耦合模式对海洋中尺度活动具有一定的模拟代表性,且耦合资料同化能形成较为平衡和协调的耦合模式初始条件,该系统对台风生成具有一定的预报技巧,对区域内的降水预报也有一定程度的改进.接下来还需进一步改进陆气交界面以及海气交界面细节性边界层物理过程的模拟描述,以期进一步提高区域内大气海洋环境的预报精度和延长可用预报时效.

Experimental exploration to thermal infrared imaging for detecting the transient process of solid impact

Based on the analysis and the comparison of stress pattern analysis by thermal emission (SPATE) and remote sensing rock mechanics (RSRM), the idea to detect the transient process of solid impact with thermal infrared (TIR) imaging technology is introduced. By means of TVS-8100MKII TIR imaging system, which has high recording speed, high space distinguishability and high temperature sensibility, TIR imaging experiments on free falling steel ball impacting on marble, granite, concrete, steel, organic-glass and wood plate are conducted. It was discovered that: (i) the target’s TIR temperature increases remarkably after impact; (ii) when ball’s size is not changed, the variation amplitude of target’s TIR temperature proportionally increases with the ball’s potential energy or falling height; (iii) the variation amplitude of target’s TIR temperature is involved with the material type and the surface glabrous condition of the target, and the amplitudes are in order as concrete, unpolished marble, steel plate,

Detection of infectious dengue virus by selective real-time quantitative polymerase chain reaction

Dear Editor,The dengue virus(DENV)is a single-stranded positivesense RNA virus that belongs to the family Flaviviridae(Gubler,2002),and has four serotypes,DENV1–DENV4,which are transmitted via Aedes aegypti and Aedes albopictus(Rodriguez-Roche and Gould,2013).It has been reported that more than 50 million dengue infections occur each year(Guzman et al.,2010),and a serious outbreak occurred in the Southern Provinces

Surfactant-Encapsulated Polyoxometalate Complex as a Cathode Interlayer for Nonfullerene Polymer Solar Cells

An alcohol-soluble,environmentally friendly,and low-cost surfactant-encapsulated polyoxometalate complex[(C8H17)4N]4[SiW_(12)O40](TOASiW_(12))as a cathode interlayer(CIL)has exhibited excellent universality for various active layers and cathodes in nonfullerene polymer solar cells(NF-PSCs).In particular,incorporating TOASiW_(12) as the CIL enhanced power conversion efficiencies(PCEs)of the PM6:Y6-based NF-PSCs with Al or Ag cathode to 16.14%and 15.89%,respectively,and the PCEs of PM6:BTP-BO4Cl-based NF-PSCs with Al or Ag cathode to 17.04%and 17.00%,respectively.More importantly,the performances of the devices with TOASiW_(12) were insensitive to the TOASiW_(12) thickness from 3 to 33 nm.Furthermore,the NF-PSCs with TOASiW_(12) exhibited better device stability.Combined characterization of the photocurrent density versus effective voltage,capacitance versus voltage and electron mobility demonstrated that TOASiW_(12) as the CIL effectively promoted exciton dissociation,charge-carrier extraction,built-in potential,charge-carrier density,and electron mobility in the NF-PSCs.These findings suggest that TOASiW_(12) is a promising,competitive CIL for NF-PSCs fabricated by roll-to-roll processing.

Acceleration of global mean ocean circulation under the climate warming

In the context of continued greenhouse gas emissions,the Earth has experienced very rapid warming over the past several decades.As the main reservoir of the Earth’s climate system,the ocean transfers much of the extra heat,which leads to long-term atmospheric warming,from sea surface to the deep oceans(IPCC,2019).Large-scale ocean circulation is one of the basic forms of sea water movement.

From Mechanically Interlocked Structures to Host-Guest Chemistry Based on Twisted Dimeric Architectures by Adjusting Space Constraints

Mechanically interlocked molecules(MIMs)and host–guest chemistry have received great attention in the past few decades.However,it remains challenging to design architectures with mechanically interlocked features and construct cavities for guest molecule recognition using similar building blocks.In this study,we designed and constructed a series of novel twisted supramolecular structures by assembling various multitopic terpyridine(tpy)ligands with the same diameter and Zn(II)ions.The obtained complexes exhibited evolutional architectures and showed distinctively different space-constraint effects.Specifically,the assembled dimer SA,SB,and SBH displayed mechanically interlocked phenomena,including[2]catenane and[3]catenane,with an increase in concentration.However,no interlocked structures were observed in complexes SC and SCH constructed by hexatopic tpy ligands due to the significant space constraints.The single-crystal data of complex SCH further proved significant space constraints and illustrated the formation of a relatively closed cavity,which showed excellent host–guest properties for different calixarenes,especially high affinity for calix[6]arene.

Polyoxometalate-Based Ionic Frameworks for Highly Selective CO_(2) Capture and Separation

During the utilization of structural and functional advantages of polyoxometalates(POMs)for enhanced applications,a suitable assembly of these clusters in framework materials to act as binding nodes represents a promising approach.In contrast to well-developed coordination/covalent combinations,we have developed a convenient strategy to build porous structures of POMs with smaller-sized counterions as bridging ligands via ionic interactions to reinforce their capability in gas adsorption in parallel to metal-organic frameworks(MOFs)/covalent organic frameworks(COFs).With this goal,a series of POMs-based ionic frameworks(IFs)were constructed with triol-ligand modified Anderson-Evans-type clusters as building blocks,and their sodium counter-cations were used as linkers.The three-dimensional(3D)open-frameworks obtained displayed unusually selective CO_(2) capturing capability and efficient separation from their N_(2),H_(2),and CH_(4) mixtures under low pressure at room temperature.Among the synthesized IFs,the cobalt-centered cluster exhibited the best performance for the uptake and selective separation of CO_(2) over N_(2) and CH_(4) in a range of 0-1 bar,while the nickel-centered cluster displayed the highest selectivity over H_(2) at 1 bar.Breakthrough experiments based on real binary gas mixtures demonstrated that the cobalt-containing framework illustrated high performance in the actual gas separation and sustained stability against a simulated operating environment.

Porous Assembly of Metallo-Supramolecule and Polyoxometal-ate via Ionic Complexation with Vapor Sorption Properties

Porous materials have been extensively developed and displayed special applications in diverse fields,however,it still remains a great challenge in developing new synthetic methods with features of energy-saving and easy-operating.In this study,we reported the construction of a series of novel ionic complexes based on discrete supramolecular triangle structure and polyoxometalate[Mo_(6)O_(19)]^(2-),using a quite efficient strategy.The obtained composites exhibit precise 3D network structures with ideal stability con-taining micropores,which were characterized by the 1H NMR,ESI-MS,TEM,SEM,and single-crystal X-ray diffraction.These compo-sites showed differential vapor adsorption behaviors for benzene,toluene,and cyclohexane.This work provides a novel approach for fabricating porous materials through electrostatic interactions and has great potential for gas separation.