Metal-organic-framework-derived copper-based catalyst for multicomponent C-S coupling reaction

Copper-based metal-organic frameworks(Cu-MOFs)are a promising multiphase catalyst for catalyzing C-S coupling reactions by virtue of their diverse structures and functions.However,the unpleasant odor and instability of the organosulfur,as well as the mass-transfer resistance that exists in multiphase catalysis,have often limited the catalytic application of Cu-MOFs in C-S coupling reactions.In this paper,a Cu-MOFs catalyst modified by cetyltrimethylammonium bromide(CTAB)was designed to enhance mass transfer by increasing the adsorption of organic substrates using the long alkanes of CTAB.Concurrently,elemental sulfur was used to replace organosulfur to achieve a highly efficient and atom-economical multicomponent C-S coupling reaction.

A Comprehensive Evaluation Framework of Water-Energy-Food System Coupling Coordination in the Yellow River Basin,China

For mankind’s survival and development,water,energy,and food(WEF)are essential material guarantees.In China,however,the spatial distribution of WEF is seriously unbalanced and mismatched.Here,a collaborative governance mechanism that aims at nexus security needs to be urgently established.In this paper,the Yellow River Basin in China with a representative WEF system,was selected as a case.Firstly,a comprehensive framework for WEF coupling coordination was constructed,and the relationship and mechanism between them were analyzed theoretically.Then,we investigated the spatiotemporal characteristics and driving mechanisms of the coupling coordination degree(CCD)with a composite evaluation method,coupling coordination degree model,spatial statistical analysis,and multiscale geographic weighted regression.Finally,policy implications were discussed to promote the coordinated development of the WEF system.The results showed that:1)WEF subsystems showed a significant imbalance of spatial pattern and diversity in temporal changes;2)the CCD for the WEF system varied little and remained at moderate coordination.Areas with moderate coordination have increased,while areas with superior coordination and mild disorder have decreased.In addition,the spatial clustering phenomenon of the CCD was significant and showed obvious characteristics of polarization;and 3)the action of each factor is self-differentiated and regionally variable.For different factors,GDP per capita was of particular importance,which contributed most to the regional development’s coupling coordination.For different regions,GDP per capita,average yearly precipitation,population density,and urbanization rate exhibited differences in geographical gradients in an east-west direction.The conclusion can provide references for regional resource allocation and sustainable development by enhancing WEF system utilization efficiency.

Framework of Distributed Coupled Atmosphere-Ocean-Wave Modeling System

In order to research the interactions between the atmosphere and ocean as well as their important role in the intensive weather systems of coastal areas, and to improve the forecasting ability of the hazardous weather processes of coastal areas, a coupled atmosphere-ocean-wave modeling system has been developed. The agent-based environment framework for linking models allows flexible and dynamic information exchange between models. For the purpose of flexibility, portability and scalability, the framework of the whole system takes a multi-layer architecture that includes a user interface layer, computational layer and service-enabling layer. The numerical experiment presented in this paper demonstrates the performance of the distributed coupled modeling system.

A Water-Heat-Force Coupled Framework for the Preparation of Soils for Application in Frozen Soil Model Test

The freezing of soil containing a liquid is a complex transient heat conduction problem involving phase change and release or absorption of latent heat.Existing efforts have essentially focused on theoretical research and numerical simulations.In the present study,the problem is approached from an experimental point of view using the so-called“freezing model test”method.In particular,in order to establish a precise relationship between the model and the prototype,a temperature similarity criterion is derived using the condition of an equal number of Kosovitch.Similarity is also established with respect to other aspects.A similarity criterion for the water field is determined on the basis of relevant partial differential equations.Analogous criteria for the stress field and load are derived using an elastic model.The validity of this approach is experimentally verified.The research results provide a practical and reasonable method for calculating the parameters for preparing model soils.They also constitute a theoretical basis and a technical support for the design and implementation of a water-heat-force similarity coupled framework.

Engineering Spin States of Isolated Copper Species in a Metal-Organic Framework Improves Urea Electrosynthesis

The catalytic activities are generally believed to be relevant to the electronic states of their active center, but understanding this relationship is usually difficult. Here, we design two types of catalysts for electrocatalytic urea via a coordination strategy in a metal–organic frameworks: Cu^(Ⅲ)-HHTP and Cu^(Ⅱ)-HHTP. Cu^(Ⅲ)-HHTP exhibits an improved urea production rate of 7.78 mmol h^(−1)g^(−1) and an enhanced Faradaic efficiency of 23.09% at-0.6 V vs. reversible hydrogen electrode, in sharp contrast to Cu^(Ⅱ)-HHTP.Isolated CuⅢspecies with S = 0 spin ground state are demonstrated as the active center in Cu^(Ⅲ)-HHTP, different from Cu^(Ⅱ) with S = 1/2 in Cu^(Ⅱ)-HHTP. We further demonstrate that isolated Cu^(Ⅲ)with an empty dx2-y20orbital in Cu^(Ⅲ)-HHTP experiences a single-electron migration path with a lower energy barrier in the C–N coupling process, while Cu^(Ⅱ)with a single-spin state( d_(x2-y2)^(1)) in Cu^(Ⅱ)-HHTP undergoes a two-electron migration pathway.

基于数据融合的隧道结构安全性能感知体系框架

随着交通基础设施建设持续扩大,大量隧道进入养护维修高峰期,结构安全风险呈滚动式周期性爆发趋势。目前隧道结构健康监测信息化和智能化程度较低,安全性能感知困难,严重影响了隧道的正常运维。本文立足于隧道结构健康监测和决策需求,提出了一种基于数物交互和数据融合的隧道结构安全性能感知体系框架。首先对隧道结构受力状态感知技术及其误差传播规律进行分析,并采用数物空间交互试验对支护结构各构件相互力学关系进行研究,并基于此建立多源数据各监测量之间的数学模型,对隧道整体结构和各构件的安全性能进行评估。结构安全感知体系可为隧道安全防灾和运维管理提供决策依据,对提高隧道工程现代化、信息化、智慧化管理水平具有重要意义。

包容适应与风险防范:生成式人工智能助推政府治理现代化的耦合框架

从ChatGPT到Sora,生成式人工智能(GAI)对政府治理带来了难以忽视的冲击,从技术与治理的双重变革出发,对其与治理现代化的耦合逻辑展开研究。研究表明:第一,构建“有用性—易用性—风险性”耦合框架进行分析,兼顾GAI的智能算力与政府行为、公众行为分析GAI对政府的影响。第二,以“政府—公众”双轮驱动模型为视角,分析得出具体影响包括“行政组织—政务服务—数据安全”三个维度。分别表现在治理体系的创新调整、治理能力的创新提效、治理全过程的创新平衡。第三,提出包容适应与风险防范两条实践逻辑。本文以期为GAI助推政府治理现代化进程提供理论与实践方向的启发。

构建多活性位点的单组分金属卤化物@吡啶/咪唑多孔有机框架用于CO_(2)的高效吸收与催化

定向设计的多孔有机框架被认为是提高CO_(2)捕集与利用效率的优异纳米材料。本研究通过ZnCl_(2)催化的氰基离子热聚合反应以及合成后修饰法构建了一系列多活性位点的单组分金属卤化物@吡啶/咪唑多孔有机框架材料(M@PIPOFs),并详细探讨了不同单体浓度和聚合温度对材料结构及性能的影响。作为具有较高比表面积、多层次孔隙结构的多相催化材料,M@PIPOFs同时含有丰富的氢键供体基团、Lewis酸/碱基团和亲核基团,在吸收CO_(2)以及催化CO_(2)与环氧化物耦合制备环状碳酸酯方面表现出极好的性能。结果表明,该类材料对CO_(2)的吸附性能较强,在273 K、100 kPa CO_(2)压力下吸附量最高,为3093μmol/g。考察了M@PIPOFs结构和反应条件对其催化性能的影响,结果表明,单组分1.0ZnI_(2)@PIPOF-400-30材料具有最高的催化性能。其能够在无溶剂、无助催化剂的条件下,高活性、高选择性地催化CO_(2)与含有不同终端基团的环氧化物耦合,并以88%~98%的收率生成相对应的环状碳酸酯。此外,该M@PIPOFs催化剂回收简单,具有持久的高稳定性和催化活性。最后,基于对M@PIPOFs材料的表征和催化数据分析,提出了一种可行的多活性位点单组分催化机理。本研究希望能够为后续高效多相催化体系的设计、开发提供参考。

基于外部效益内部化的生态产品价值实现理论框架

外部性是生态产品供给不足的重要原因之一,生态产品价值实现是解决环境外部性、保护生态系统功能和完整性的重要机制。基于公共产品理论和外部性理论,明确生态产品具有价值复杂、公共属性、交易不均等外部性特征;运用比较分析方法和演绎方法,探讨了不同政策工具导向下生态产品的外部性特征及其价值实现的作用机制和理论框架。研究发现:(1)生态产品价值实现与外部效益内部化在理论基础、发展历程、实践路径、实现模式等四个方面具有高度耦合协同关系;(2)生态产品外部效益内部化需要依托供需承载空间,从自然生态系统和社会经济系统两个角度构建自然层面的“资源本底⁃产权关系⁃资源属性”以及社会层面的“发展环境⁃参与主体⁃发展模式”的作用机制;(3)从生态、社会、空间三个维度构建“资源属性⁃社会因素⁃供需空间”的“4+3+3”的生态产品外部效益内部化的理论框架。本研究阐明了生态产品外部性内部化的作用机制,构建的外部效益内部化理论框架为生态产品价值精准高效实现提供理论启示。

基于校准窗口集成与耦合市场特征的可解释双层日前电价预测

随着电力市场之间耦合程度不断加深,只局限于单个市场内部的传统特征集不足以支撑高精度预测的需求。而且模型预测性能对校准窗口的选择敏感,而传统电价预测仅使用一个固定时间长度的数据集,同时预测模型的“黑盒”结构导致预测结果在工程应用中可信度偏低。针对上述问题,该文提出一种考虑校准窗口集成与耦合市场特征的可解释双层日前电价预测框架。内层框架为基于改进自适应噪声完备集合经验模态分解(improved complete ensemble empirical mode decomposition,ICEEMDAN)的择优预测,首先分解原始电价序列,然后应用Lasso估计回归(lassoestimated autoregressive,LEAR)、长期和短期时间序列网络(long-term and short-term time-series networks,LSTNet)、卷积神经网络-长短记忆神经网络(convolutionalneuralnetworks-longshort termmemory,CNN-LSTM)、移动平均(autoregressive integrated moving average,ARIMA)和核极限学习机(kernel extreme learning machines,KELM)模型预测子序列并选择最优预测算法。外层框架为基于贝叶斯模型平均(bayes modelaveraging,BMA)的校准窗口集成预测,针对每个不同校准窗口长度数据集下的预测分配权重并集成得到预测电价。最后,通过可解释方法沙普利加性解释模型(shapley additiveexplanations,SHAP)分析耦合市场特征如何影响预测电价。该文通过北欧电力市场数据集的算例分析证明了所提算法的优越性和校准窗口集成方案的有效性。

共价有机框架负载钯催化Suzuki偶联的研究进展

共价有机框架是一类通过共价键连接有机分子而构建的多孔结晶聚合物。这些材料具有高度有序的结构,并且拥有永久性孔隙,因此在气体存储、分离、催化以及光电器件等多个领域有着广泛的应用前景。Suzuki偶联反应作为有机合成化学中构建碳-碳键的高效手段之一,长期依赖于将贵金属钯作为经典催化剂。但传统的均相钯催化剂面临回收难、重复利用性差、与反应产物难以分离等挑战,使用共价有机框架负载钯催化剂则有望解决上述问题,因此受到广泛关注。本文综述了近年来共价有机框架负载钯催化剂在Suzuki偶联反应中的研究进展,同时对其发展前景进行了展望。

基于协同优化的耐压柱壳多学科多目标优化

为提高耐压柱壳的设计效率和结构性能,本文基于多学科设计优化思想,进行了耐压柱壳多学科设计优化的学科分解,确定了耐压柱壳多学科优化设计的设计参数,明确了设计变量间的耦合关系,设计了耐压柱壳参数化分析流程,进行了设计变量灵敏度分析。在利用响应面模型建立了具有较高拟合精度耐压柱壳近似模型的基础上,以质量排水量比和极限载荷为目标函数,建立了基于协同优化方法的耐压柱壳多学科多目标优化模型,在确定了系统层和学科层的优化求解方法基础上,设计了基于协同优化的耐压柱壳多学科多目标优化框架,进行了优化的求解工作,得到了优化方案。与初始方案的对比表明:所得到的Pareto解集中,部分方案在2个目标函数上均得到了优化,验证了优化框架的有效性。

Dynamic-static coupled sensing of trace biomarkers by molecularly imprinted metal-organic frameworks

Accommodating target analytes within the pores of metal-organic frameworks(MOFs)to improve the sensing performance is an important but challenging task.Here,we report a novel molecular imprinting strategy to create target recognition sites in a tailored multicomponent MOF with the inter-ligand synergistic antenna effect to lanthanide ions,enabling selective recognition of trace biomarkers,which is critical to the early diagnosis of age-related diseases in blood samples with high sensitivity and ultralow limit of detection(LOD)of 69 nmol L^(-1).Compared with MOF-based sensors without imprinted recognition sites,the significantly enhanced sensing performance(both sensitivity and LOD)was attributed to a dynamic-static coupled sensing mechanism:the dynamic interactions involve concentrating the trace biomarkers at the imprinted recognition sites to enhance the sensing performance at ultralow concentration,and the static interactions are derived from electron/energy exchange between the molecularly imprinted MOF and the biomarker to govern the sensing performance.This work establishes a new molecular imprinting strategy to attain advanced materials for sensing trace bio-analytes.

水下管汇入水冲击数值模拟研究

基于ABAQUS软件,采用耦合欧拉-拉格朗日算法(CEL)对水下管汇入水工况中框架响应进行数值模拟。根据管汇框架入水受力特点,选取其局部结构(工字梁)建立入水数值模型,其中工字梁采用壳单元模拟,海水区域采用欧拉网格离散,为模拟管汇质量的影响,采用等效密度方式修正工字梁质量。模拟了工字梁入水过程,计算了关键部位速度和应力时间历程,给出了不同时间点的应力场,讨论了初始速度对最大Mises应力的影响,为管汇框架入水强度分析奠定了基础。

Tectonic relationship between the Kelameili range and the Dajing depression: Insights into the Carboniferous tectonic-sedimentary framework

Based on comprehensive analysis of typical outcrops, latest deep wells drilled and high resolution seismic profiles in the study area, we examined the geologic structure of the Kelameili range, and analyzed the structural relationship between the Kelameili range and the Dajing depression, and discussed the tectonic-sedimentary framework in different periods of Carboniferous by using axial surface analysis and balanced section techniques. Understandings in three aspects are achieved:(1) The study area experienced five stages of compressional tectonic movements, the Early Carboniferous, the Late Carboniferous, the Middle-Late Permian, Late Cretaceous and Paleogene, and three stages of extensional tectonic movements, the middle-late Early Carboniferous, the middle-late Late Carboniferous and Early Permian. At the end of the Early Permian and the Mid-Late Cretaceous, the tectonic wedges moved southward respectively.(2) The Kelameili range and Dajing depression had the first basin-range coupling during the early Early Carboniferous, basin-range decoupling in the following middle-late Early Carboniferous to the Early Permian, then basin-range strong recoupling in the Middle Permian, and the basin-range coupling had been inherited in the subsequent Indosinian, Yanshanian and Himalayan movements.(3) During the early Early Carboniferous, the study area was a foreland basin where the Dishuiquan Formation source rock developed;in mid-late Early Carboniferous, a series of NW-and NWW-trending half-garben fault basins developed, where the Songkaersu Formation volcanic reservoir formed. In late Early Carboniferous, the study area entered into depression basin stage after rifting, and the Shuangjingzi Formation source rock developed;in the mid-late Late Carboniferous, Batamayineishan fault basin emerged, and the Upper-Carboniferous volcanic reservoir was formed, affected by the tectonic compression during late Carboniferous and Mid-Permian, the Batamayineishan Formation suffered extensive erosion, and only partially remains in the piedmont depression zone.

Iron-based binary metal-organic framework nanorods as an efficient catalyst for the oxygen evolution reaction

First-row transition metal compounds have been widely explored as oxygen evolution reaction(OER)electrocatalysts due to their impressive performance in this application.However,the activity trends of these electrocatalysts remain elusive due to the effect of inevitable iron impurities in alkaline electrolytes on the OER;the inhomogeneous structure of iron-based(oxy)hydroxides further complicates this situation.Bimetallic metal-organic frameworks(MOFs)have the advantages of well-defined and uniform atomic structures and the tunable coordination environments,allowing the structure-activity relationships of bimetallic sites to be precisely explored.Therefore,we prepared a series of iron-based bimetallic MOFs(denoted as Fe_(2)M-MIL-88B,M=Mn,Co,or Ni)and systematically compared their electrocatalytic performance in the OER in this work.All the bimetallic MOFs exhibited higher OER activity than their monometallic iron-based counterpart,with their activity following the order FeNi>FeCo>FeMn.In an alkaline electrolyte,Fe2Ni-MIL-88B showed the lowest overpotential to achieve a current density of 10 mA cm^(–2)(307 mV)and the smallest Tafel slope(38 mV dec^(–1)).The experimental and calculated results demonstrated that iron and nickel exhibited the strongest coupling effect in the series,leading to modification of the electronic structure,which is crucial for tuning the electrocatalytic activity.

多要素驱动区域创新链耦合协调度提升的路径研究——TOE框架下的fsQCA分析

有效提升区域创新链耦合协调度是实施创新驱动发展战略过程中亟待解决的现实问题。基于“知识创新—研发创新—产品创新”区域创新链,在“技术—组织—环境”(TOE)理论框架下,运用模糊集定性比较分析(fsQCA)方法,对中国内地31个省份开展评价,探究多要素驱动区域创新链耦合协调度提升的条件组态和路径。研究结果表明,东、中、西部各省份存在显著差异,且有效提升区域创新链耦合协调度的关键要素有2个,即数字化技术水平、市场化水平;提升路径为4条,即知识—研发—产品创新均衡型、研发—产品创新引领型、知识—研发创新引领型、产品创新引领型。上述结论有助于拓展区域创新链研究视角,同时,对提升不同地区区域创新链耦合协调度具有现实价值。

基于DPSIR模型的黄金行业绿色矿山建设综合评价研究

针对当前绿色矿山评价过程中存在的主观因素影响较大的问题,以黄金行业为例,基于驱动力—压力—状态—影响—响应框架模型,从5个层面构建指标体系。结合主客观组合赋权法确定指标权重,引入TOPSIS和耦合协调度模型定量评价绿色矿山建设时空演化过程及子系统间的耦合协调性,分析得出影响企业绿色矿山建设的主要障碍因子,为企业绿色矿山建设改进提供对策建议。通过对陕西某金矿的实际案例分析,验证了模型的适用性。本研究系统整合了绿色矿山评价指标,完善并优化了绿色矿山建设评价方法,使评价结果更加公平可靠,为推进矿山可持续发展提供了有效途径。

科研大数据协同治理:体系构建与实施路径

[目的/意义]协同治理是科研大数据实现健康发展的必然要求,厘清科研大数据协同治理的维度与脉络,能更好地实现科研大数据协同发展,从而为科研创新活动奠定坚实的数据“基石”。[方法/过程]对科研大数据协同治理进行概念界定与特性分析,以此为基础构建科研大数据协同治理框架体系(CGFS-SRBD),从规制、技术、网络、文化4个维度分析科研大数据协同治理的活动机理,依据“初生—再生—共生—反馈—分解”五阶段,进一步提出科研大数据协同治理的实施路径。[结果/结论]研究表明,科研大数据协同治理是以层级相济性、迭代循环性、数据云化性、生态趋向性为特性,以规制协同为重要原则,以技术协同为能力基础,以网络协同为核心组成,以文化协同为内化实质,以“层链式”遗传响应路径、“阶梯式”携作迭升路径、“矩阵式”分化管控路径、“螺旋式”纵贯耦合路径为实施路径,以实现科研大数据从混乱到整齐、从无序到有序、总体向好发展为目标的动态、多维过程。科研大数据协同治理体系的构建及实施路径的提出有助于在推动国家大数据战略目标的同时实现科研数据价值最大化。

高校工会与乡村文化振兴的耦合点及实施路径研究——以西安电子科技大学工会帮扶蒲城县为例

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