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Emergent symmetry in quantum phase transition:From deconfined quantum critical point to gapless quantum spin liquid

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Science Bulletin 2024年第2期69卷 190-196页

作者： Wen-Yuan Liu Shou-Shu Gong Wei-Qiang Chen Zheng-cheng gu Department of Physics The Chinese University of Hong KongHong KongChina Division of Chemistry and Chemical Engineering California Institute of TechnologyPasadena CA 91125USA School of Physical Sciences Great Bay UniversityDongguan 523000China Great Bay Institute for Advanced Study Dongguan 523000China Department of Physics and Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices Southern University of Science and TechnologyShenzhen 518055China

The emergence of exotic quantum phenomena in frustrated magnets is rapidly driving the development of quantum many-body physics,raising fundamental questions on the nature of quantum phase transitions.Here we unveil the behaviour of emergent symmetry involving two extraordinarily representative phenomena,i.e.,the deconfined quantum critical point(DQCP)and the quantum spin liquid(QSL)state.Via large-scale tensor network simulations,we study a spatially anisotropic spin-1/2 square-lattice frustrated antiferromagnetic(AFM)model,namely the J1x-J1y-J2 model,which contains anisotropic nearestneighbor couplings J1x,J1y and the next nearest neighbor coupling J2.For small J1y/J1x,by tuning J2,a direct continuous transition between the AFM and valence bond solid phase is observed.With growing J1y/J1x,a gapless QSL phase gradually emerges between the AFM and VBS phases.We observe an emergent O(4)symmetry along the AFM–VBS transition line,which is consistent with the prediction of DQCP theory.Most surprisingly,we find that such an emergent O(4)symmetry holds for the whole QSL–VBS transition line as well.These findings reveal the intrinsic relationship between the QSL and DQCP from categorical symmetry point of view,and strongly constrain the quantum field theory description of the QSL phase.The phase diagram and critical exponents presented in this paper are of direct relevance to future experiments on frustrated magnets and cold atom systems.

关键词： Tensor network Quantum phase transition Emergent symmetry Quantum spin liquid Deconfined quantum critical point Anisotropic

Controlled Synthesis of Proton-Conductive Porous Organic Polymer Gels via Electrostatically Stabilized Colloidal Formation

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CCS Chemistry 2024年第7期6卷 1767-1775页

作者： Bin Chen Yifeng Kuang Lu Liu Linkun Cai Zaoming Wang Panchao Yin Liangbin Huang cheng gu State Key Laboratory of Luminescent Materials and Devices Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyGuangzhou 510640 College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065 Key Laboratory of Functional Molecular Engineering of guangdong Province School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510641 South China Advanced Institute for Soft Matter Science and Technology South China University of TechnologyGuangzhou 510640 Institute for Integrated Cell-Material Sciences Institute for Advanced StudyKyoto UniversityKyoto 606-8501

Porous organic polymers(POPs)have attracted extensive interest due to their structural diversity and predesigned functionality.However,the majority of POPs are synthesized as insoluble and unprocessable powders,which greatly impede their advanced applications because of limited mass transport and inadaptation for device integration.Herein,we report a controlled synthetic strategy of macroscopic POP gels by a cation-stabilized colloidal formation mechanism,which is widely adaptable to a large variety of tetra-/tri-amino build blocks for the synthesis of Tröger’s base-linked POP gels,aerogels,and ionic gels.The POP gels combined the integrated advantages of hierarchically porous structures and tailorable mechanical stiffness,whereas they could load substantial amounts of phosphoric acids and construct unimpeded transport pathways for proton conduction,exhibiting unprecedented proton conductivity at subzero temperatures.Our strategy offers a new solution to the intractable processing issues of POPs toward device applications with cutting-edge performances.

关键词： porous organic polymers Tröger’s base linkage gels superprotonic conduction subzero temperatures

Decorating Covalent Organic Frameworks with High-density Chelate Groups for Uranium Extraction

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Chemical Research in Chinese Universities 2022年第2期38卷 433-439页

作者： QIN Xudong TANG Xiaohui MA Yu XU Hong XU Qing YANG Weiting gu cheng State Key Laboratory of Luminescent Materials and Devices Institute of Polymer Optoelectronic Materials and DevicesSouth China University of TechnologyGuangzhou 510640P.R.China Key Laboratory of Advanced Materials of Tropical Island Resources Ministry of EductionSchool of Chemical Engineering and TechnologyHainan UniversityHaikou 570228P.R.China CAS Key Laboratory of Low-Carbon Conversion Science and Engineering Shanghai Advanced Research Institute(SARI)Chinese Academy of Sciences(CAS)Shanghai 201210P.R.China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084P.R.China guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates South China University of TechnologyGuangzhou 510640P.R.China

The extraction of uranium from aqueous solution is highly desirable for sustaining the increasing demand for environmental safety and nuclear fuel.Herein,we report a strategy using a two-step covalent modification for the synthesis of covalent organic frameworks(COFs)with high-density amidoxime chelate groups at periphery.The introduction of dense amidoxime groups plays a pivotal role in uranium adsorption.The resulting COF exhibits strong affinity with the distribution coefficient of 5.2×104 mL/g and a high adsorption capacity of 319.9 mg/g.The strategy could be expanded to identify and remove different contaminants by introducing special functional groups.

关键词： Two-step post-synthetic modification High-density amidoxime Uranium adsorption

In situ protonation in a locally flexible porous coordination polymer for enhancing proton-carrier loading and proton conductivity

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Science China Chemistry 2024年

作者： Xianzhe Wei Jincheng Liu Yan Su Weitao Wang guixiang Wang Gen Zhang Ping Wang cheng gu State Key Laboratory of Luminescent Materials and Devices Institute of Polymer Optoelectronic Materials and Devices South China University of Technology College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering Sichuan University Key Laboratory for Soft Chemistry and Functional Materials of Ministry of Education School of Chemistry and Chemical EngineeringNanjing University of Science and Technology

Designing efficient proton-conductive materials is crucial in fuel cells. Yet, it remains a substantial challenge because of the issues in proton mobility, proton-carrier amount, and orientation of proton host materials. Herein, we report an in-situ protonation strategy to produce a locally flexible porous coordination polymer(PCP) to enhance the proton-carrier loading and proton conductivity. The local dipole flipping of the ligand allows effective proton exchange with low activation energy, promoting interpore proton transport through the pore apertures and pore walls. The protonation induces substantial charges to the frameworks and enhances the interaction with proton carriers, thereby increasing the loading of the proton carriers. By this design strategy, the resulting PCP exhibits enhanced phosphoric acid loading and extraordinary proton conductivities under both aqueous and anhydrous conditions compared to its isoreticular analog that features rigidity without proton-exchange capability.Our work provides a new avenue for designing proton-conductive materials that combine structural dynamics with performance merits.

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财政分权、审计监督与地方政府回应性——来自市级民生财政支出的经验证据

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财贸经济 2024年第6期45卷 21-37页

作者：谷成张家楠东北财经大学财政税务学院 116025 东北财经大学法学院 116025

对社会成员的公共需求做出积极有效的回应是现代国家的重要职能。在政府和社会成员通过协商互动共同解决社会问题的过程中,现代国家治理越来越清晰地表现出治理结构分权化、治理方式民主化、治理技术现代化等特征。为考察财政分权对地... 详细信息

对社会成员的公共需求做出积极有效的回应是现代国家的重要职能。在政府和社会成员通过协商互动共同解决社会问题的过程中,现代国家治理越来越清晰地表现出治理结构分权化、治理方式民主化、治理技术现代化等特征。为考察财政分权对地方政府回应性的影响,本文构建了一个包含“中央政府-地方政府-社会成员”三元主体的回应性理论框架,并基于中国282个地级市2010一2018年2538个民生财政支出样本数据,采用双向固定效应模型进行实证分析。研究结果显示,财政分权通过降低地方政府的回应能力和回应意愿抑制地方政府对辖区民生需求的回应性。尽管审计监督在一定程度上提高了地方政府对民生需求的回应性,但仍不足以抵消财政分权引发的回应性削弱。原因在于审计监督只在一定程度上保障了地方政府的回应能力,而对地方政府的回应意愿并无影响。本文的研究不仅深化了有关政府回应性影响因素的探索,也为财政体制改革和创新提供了新的视角和理论依据。

关键词：财政分权审计监督政府回应性现代国家治理

供应链政策与供应链效率——基于供应链创新与应用的准自然实验

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哈尔滨商业大学学报（社会科学版） 2024年第1期 33-48页

作者：谷城徐杰东北师范大学经济与管理学院长春130117 哈尔滨商业大学经济学院哈尔滨150028

提升供应链效率是确保国民经济循环畅通的关键,亦是推动经济高质量发展的重要路径。借助供应链创新与应用试点政策的准自然实验,以2013—2022年A股上市公司为研究样本,实证检验试点政策对供应链效率的影响。研究发现:供应链创新与应用... 详细信息

提升供应链效率是确保国民经济循环畅通的关键,亦是推动经济高质量发展的重要路径。借助供应链创新与应用试点政策的准自然实验,以2013—2022年A股上市公司为研究样本,实证检验试点政策对供应链效率的影响。研究发现:供应链创新与应用试点政策的实施可以提高供应链效率。机制检验结果表明,试点政策主要通过提高创新效率、优化内部控制水平和缓解融资约束来提高供应链效率。异质性检验结果表明,对于国有企业、供应链关系紧密程度低、知识产权保护强地区以及所处试点城市的企业,试点政策对供应链效率提升作用更为显著。拓展分析发现,试点政策存在行业溢出效应和经济后果,试点政策对同行业非试点企业供应链效率具有显著的促进作用,同时试点政策可以通过提高供应链效率促进企业绩效。

关键词：供应链政策供应链效率创新效率内部控制融资约束

智慧物流与企业可持续发展——基于经济绩效与环境绩效的双重验证

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产业经济研究 2024年第1期 42-55页

作者：张树山谷城东北师范大学经济与管理学院吉林长春130117

在“双碳”战略目标和可持续发展背景下,智慧物流为促进企业可持续发展提供了新契机。利用2009—2021年我国地级及以上城市数据,测度城市层面智慧物流水平,并将其与A股制造业上市公司数据进行匹配,考察了智慧物流对企业经济绩效和环境... 详细信息

在“双碳”战略目标和可持续发展背景下,智慧物流为促进企业可持续发展提供了新契机。利用2009—2021年我国地级及以上城市数据,测度城市层面智慧物流水平,并将其与A股制造业上市公司数据进行匹配,考察了智慧物流对企业经济绩效和环境绩效的影响。结果表明,智慧物流对企业经济绩效和企业环境绩效具有显著的正向影响,这意味着智慧物流可以促进企业可持续发展。机制检验表明,智慧物流通过发挥成本效应、市场整合效应以及学习效应三种机制促进企业可持续发展。异质性分析表明:智慧物流的可持续发展效应主要存在于交通条件便利地区和外部媒体关注度高的企业;对于市场激励型环境规制地区,智慧物流仅发挥了经济效应。拓展研究发现,智慧物流对企业可持续发展的影响具有网络效应,现代物流创新发展试点政策的激励作用尚未实现经济与环境“和谐共生”。研究结论为我国政府优化智慧物流政策和“双碳”愿景下制造业企业实现可持续发展提供了路径选择。

关键词：智慧物流可持续发展交易成本市场一体化学习效应网络效应

增材制造钛基金字塔点阵结构对镁/钛双金属复合材料界面强化的优化

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Transactions of Nonferrous Metals Society of China 2024年第3期34卷 846-860页

作者：吴远兵赵建华彭韦力辜诚程进王亚军重庆大学材料科学与工程学院重庆400045 重庆大学国家镁合金工程研究中心重庆400044

采用超声辅助固-液复合铸造的方法,通过在界面处采用增材制造的钛基金字塔型点阵材料制备镁/钛异种双金属复合材料。采用正交法对点阵结构参数进行优化。结果表明,优化后的点阵结构参数为:杆直径(d)1 mm,杆长与杆直径比(l/d)3,上节点和... 详细信息

采用超声辅助固-液复合铸造的方法,通过在界面处采用增材制造的钛基金字塔型点阵材料制备镁/钛异种双金属复合材料。采用正交法对点阵结构参数进行优化。结果表明,优化后的点阵结构参数为:杆直径(d)1 mm,杆长与杆直径比(l/d)3,上节点和下节点直径与杆直径比(d_(1)/d,d_(2)/d)均为2.5,其中l/dd是影响接头失效强度的最显著因素,最优点阵结构参数下镁/钛双金属接头的失效强度为77.3 MPa。实验结果和有限元分析表明:随着点阵结构长径比的增加,镁/钛双金属接头的失效强度先增加后减小,当长径比为3时,失效强度达到最大。

关键词：镁/钛双金属复合材料金字塔点阵结构优化增材制造失效强度有限元分析

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2023年税收理论研究综述

税务研究 2024年第3期 13-20页

作者：谷成齐枳涵肖涵磊东北财经大学财政税务学院

2023年是全面贯彻党的二十大精神的开局之年,是全面建设社会主义现代化国家新征程的起步之年,也是三年新冠疫情防控转段后经济恢复发展的一年。面对有效需求不足、部分行业产能过剩、社会预期偏弱、风险隐患较多、国内大循环存在堵点、... 详细信息

2023年是全面贯彻党的二十大精神的开局之年,是全面建设社会主义现代化国家新征程的起步之年,也是三年新冠疫情防控转段后经济恢复发展的一年。面对有效需求不足、部分行业产能过剩、社会预期偏弱、风险隐患较多、国内大循环存在堵点、外部环境复杂严峻、不确定性上升等困难和挑战,税收理论研究者对税收依据、税收职能、税收原则.

关键词：有效需求不足税收职能产能过剩税收原则风险隐患疫情防控理论研究综述外部环境