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工程建设与设计 2024年第4期 138-140页

作者：陈春名中铁建设集团有限公司北京100043

阐述了钢筋混凝土结构的特点以及逆向拆除技术的基本原理,结合具体案例,对逆向拆除技术在房建钢筋混凝土结构中的应用进行了详细介绍。研究结果表明,逆向拆除技术不仅可以保证拆除过程的安全,还能准确地拆解各类钢筋混凝土结构。

关键词：逆向拆除梁板刚度施工技术钢筋混凝土

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数字经济、技术进步与制造业转型升级

经济问题 2024年第4期 29-36页

作者：陈春明李朝阳陈佳馨哈尔滨理工大学经济与管理学院黑龙江哈尔滨150040 北京汽车研究总院有限公司北京101300

制造业水平是一个国家综合实力和国际竞争力的重要标志,技术进步提供了制造业转型升级的动力和基础。而数字经济作为推动技术进步和企业变革的重要力量,为传统制造业注入新的增长动力。基于2010—2020年我国省级面板数据,运用固定效应... 详细信息

制造业水平是一个国家综合实力和国际竞争力的重要标志,技术进步提供了制造业转型升级的动力和基础。而数字经济作为推动技术进步和企业变革的重要力量,为传统制造业注入新的增长动力。基于2010—2020年我国省级面板数据,运用固定效应模型和门槛效应模型实证研究数字经济背景下技术进步对我国制造业转型升级的作用机制,并探究数字经济在此过程中发挥的调节效应。研究结果显示:(1)数字经济时代下,技术进步对制造业转型升级依旧具有很强的驱动效应;(2)在技术进步对制造业转型升级的作用过程中,数字经济可以有效发挥正向调节作用;(3)技术进步驱动制造业转型升级存在显著的数字经济门槛效应。

关键词：数字经济技术进步制造业转型升级调节效应

The Cysteine Pairs in CLV2 are Not Necessary for Sensing the CLV3 Peptide in Shoot and Root Meristems

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Journal of Integrative Plant Biology 2010年第9期52卷 774-781页

作者： Xiufen Song Peng Guo chen Li chun-ming Liu Key Laboratory of Photosynthesis and Environmental Molecular Physiology Institute of Botany Chinese Academy of Sciences Beijing 100093 China

Receptor-like proteins （RLPs） are involved in both plant defense and developmental processes. Previous genetic and biochemical studies show that the leucine-rich repeat （LRR） receptor-like protein CLAVATA2 （CLV2） functions together with CLAVATA1 （CLV1） and CORYNE （CRN） in Arabidopsis to limit the stem cell number in shoot apical meristem, while in root it acts with CRN to trigger a premature differentiation of the stem cells after sensing the exogenously applied peptides of CLV3p, CLE19p or CLE40p. It has been proposed that disulfide bonds might be formed through two cysteine pairs in the extracellular LRR domains of CLV1 and CLV2 to stabilize the receptor complex. Here we tested the hypothesis by replacing these cysteines with alanines and showed that depletions of one or both of the cysteine pairs do not hamper the function of CLV2 in SAM maintenance. In vitro peptide assay also showed that removal of the cysteine pairs did not affect the perception of CLV3 peptides in roots. These observations allow us to conclude that the formation of disulfide bonds is not needed for the function of CLV2.

关键词： Proteins Protein products Roots Stems Shoots Cells Rooting Senses Peptides Cysteine

Nutrition Status of the Chinese People

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Biomedical and Environmental Sciences 1996年第2期9卷 81-92页

作者： chen chun-ming (Chinese Academy of Preventive Medicine, 27 Nan Wei Road Beijing 100050, China) Chinese Academy of Preventive Medicine Beijing China.

Based on the available data collected with national nutritional survey, nutrition surveillance and the child surveys since 1987, analysis on food consumption, dietary pattern and nutrition status of the Chinese people has been done. The data sets used for the analysis are as follows. (1) 1987 Child Survey in 9 Provinces-91011 preschool children were sampled. (2) 1992 National Child Survey-570704 children under the age of 15 were sampled, with anthropometric measurement of 185965 children under the age of 5. (3) 1990 Nutrition Surveillance-State Statistic Bureau (SSB) h usehold survey in selected 7 provinces (including Beijing Municipality) with 8629 household samples in the urban and 11840 households in the rural covered 5341 children under the age of 6, among which 1487 were in the urban and 3854 in the rural. (4) 1992 Third National Nutritional Survey-All the provinces and municipalities were covered with 25033 household samples, among which 8474 were in the urban and 16559 in the rural. 99749 residents were surveyed, among which 30723 were in the urban and 69026 in the rural. Dietary survey data is used for comparison on food consumption and nutrient intake with 1990 nutrition surveillance data

关键词： DDP Nutrition Status of the Chinese People OO

Construction of a Metallacyclopentadiene Ring through the Attack of Carbanions to M≡C Bond Followed by C—H Activation

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Chinese Journal of Chemistry 2024年第3期42卷 235-242页

作者： chun Tang Shengjie Zhang Zhengyu Lu Qian Li ming Luo Dafa chen Haiping Xia State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringCollaborative Innovation Center of Chemistry for Energy MaterialsXiamen UniversityXiamenFujian361005 China Shenzhen Grubbs Institute and Guangdong Provincial Key Laboratory of Catalysis Department of ChemistrySouthern University of Science and TechnologyShenzhenGuangdong518055 China

Metallacyclopentadienes are important metallacycles and regarded as intermediates in many reactions,therefore,new methods to achieve them are *** this study,a formal[3+2]method,through the reactions of an osmapentalyne with benzyl carbanions,was *** reactions underwent a nucleophilic attack of carbanions to the Os≡C bond,followed by C—H activation to form the five-membered osmacyclopentadiene *** of the reactions were carried out at room temperature,the substituents on the aromatic rings of benzyl carbanions are diverse,and the resulting products contain an Os—H bond,representing a novel type of 10C-carbolong *** work provides a new convenient route to construct metallacyclopentadienes,which is expected to further promote the development of such a type of substances.

关键词： Metallacyclopentadiene Carbolong chemistry Osmium C–H activation Nucleophilic addition

Elastic three-dimensional phononic topological insulators with Dirac hierarchy

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 54-62页

作者： Shao-Yong Huo Qiu-Shuang Yang Jiu-Jiu chen Hong-Kang Li Long-Chao Yao Fu-chun He chun-ming Fu College of Mechanical Engineering University of South ChinaHengyang 421001China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China

Three-dimensional(3D)phononic topological insulators(TIs)featuring two-dimensional(2D)surface states and one-dimensional(1D)hinge states have opened up a new route for multi-dimensional robust wave transport,providing unprecedented methods for integrated acoustic sensors and energy harvesting ***,aiming at the elastic 3D phononic TI with gapless surface states and hinge states,the realization of elastic 3D phononic TIs with gapless surface states and hinge states is a significant challenge due to the complicated multi-mode polarization of elastic waves in 3D *** this study,we demonstrate an elastic 3D phononic TI with a Dirac hierarchy by elaborately operating the corresponding spatial symmetries of the chiral honeycomb ***,a 3D double Dirac cone of elastic wave can be achieved by doubling the lattice along the outof-plane direction to fold two iso-frequency Weyl *** topological phase transitions and 2D gapless two-fold Dirac surface states of elastic wave are realized by breaking the half-lattice spatial translation ***,based on the Brillouin zone folding along the in-plane direction,the 2D gapless two-fold surface Dirac cones are folded into four-fold surface Dirac ***,by inducing the relative radius of adjacent holes to break the in-plane spatial inversion symmetry,the fourfold surface Dirac cones are gapped and associated with a surface state inversion,in which the gapless 1D hinge Dirac dispersion is *** research offers a route for engineering the hierarchies of TIs in 3D elastic wave systems and provides new possibilities for designing 3D ultrasonic devices with unconventional functions.

关键词： Dirac topological hierarchy

Eigenstate properties of the disordered Bose-Hubbard chain

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Frontiers of physics 2024年第4期19卷 57-72页

作者： Jie chen chun chen Xiaoqun Wang Key Laboratory of Artificial Structures and Quantum Control(Ministry of Education) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China School of Physics Zhejiang UniversityHangzhou 310058China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

Many-body localization(MBL)of a disordered interacting boson system in one dimension is studied numerically at the filling faction *** von Neumann entanglement entropy Svn is commonly used to detect the MBL phase transition but remains challenging to be directly *** on the U(1)symmetry from the particle number conservation,Svn can be decomposed into the particle number entropy S_(n) and the configuration entropy *** light of the tendency that the eigenstate's S_(c) nears zero in the localized phase,we introduce a quantity describing the deviation of S from the ideal thermalization distribution;finite-size scaling analysis illustrates that it shares the same phase transition point with Sv but displays the better critical *** observation hints that the phase transition to MBL might largely be determined by S and its fluctuations Notably,the recent experiments[***,et al.,Science 364,256(2019);***,et al.,***.19,481(2023)]demonstrated that this deviation can potentially be measured through the Sn ***,our investigations reveal that the thermalized states primarily occupy the low-energy section of the spectrum,as indicated by measures of localization length,gap ratio,and energy density *** low-energy spectrum of the Bose model closely resembles the entire spectrum of the Fermi(or spin XXZ)model,accommodating a transition from the thermalized to the localized ***,owing to the bosonic statistics,the high-energy spectrum of the model allows the formation of distinct clusters of bosons in the random potential *** analyze the resulting eigenstate properties and briefly summarize the associated *** distinguish between the phase regions at the low and high energies,a probing quantity based on the structure of S_(VN) is also *** work highlights the importance of symmetry combined with entanglement in the study of *** this regard,for the disordered Heisenberg XXZ

关键词： entanglement entropy decomposition U(1)symmetry thermalization-to-localization transition

Enhanced Crystallization of Poly(butylene adipate-co-terephthalate)by a Self-assembly Nucleating Agent

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Chinese Journal of Polymer Science 2024年第5期42卷 663-674,I0010页

作者： cheng Zhou Kun chen Zi-Heng Zhang Meng-Fan Jing chun-Tai Liu Chang-Yu Shen Ya-ming Wang State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentNational Engineering Research Center for Advanced Polymer Processing TechnologyZhengzhou UniversityZhengzhou450002China

Poly(butylene adipate-co-terephthalate)(PBAT)is a promising biodegradable flexible polymer but suffers from slow crystallization rate,making it less attractive for some applications like the injection-molded products in comparison with low-density polyethylene(LDPE).This work aimed to accelerate the crystallization of PBAT by adding a self-assembly nucleating agent octamethylenedicarboxylic dibenzoylhydrazide(OMBH).PBAT/OMBH composites with various OMBH contents(0 wt%,0.5 wt%,0.7 wt%,1 wt%,2 wt%,3 wt%and 5 wt%)were prepared through *** effect of OMBH on the crystallization behavior,morphologies and mechanical properties of PBAT was *** highest nucleation efficiency value of 59.6%was achieved for PBAT with 0.7 wt%OMBH,much higher than that of 22.7%for PBAT with 0.7 wt%*** force microscopy results showed that OMBH formed fine fibers and induced the formation of transcrystalline layers of *** transform infrared spectroscopy(FTIR)combined with two-dimensional correlation spectra suggested that the intermolecular dipole-dipole N—H…O=C interactions but not hydrogen bond between OMBH and PBAT promoted the crystallization of PBAT in the initial period of *** presence of OMBH did not change the crystal form of PBAT but had positive contribution in enhancing its crystallinity and mechanical *** work is essential for preparing PBAT with high crystallization rate,enhancing its potential applications in injection-molded products.

关键词： Poly(butylene adipate-co-terephthalate) Biodegradable Self-assembly nucleating agent Crystallization

Better use of experience from other reservoirs for accurate production forecasting by learn-to-learn method

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Petroleum Science 2024年第1期21卷 716-728页

作者： Hao-chen Wang Kai Zhang Nancy chen Wen-Sheng Zhou chen Liu Ji-Fu Wang Li-ming Zhang Zhi-Gang Yu Shi-Ti Cui Mei-chun Yang China University of Petroleum(East China) 66 Changjiang West RoadQingdao West Coast New AreaQingdao266580ShandongChina University of Calgary 2500 University Dr NWCalgaryT2N 1N4AlbertaCanada Qingdao University of Technology Qingdao266071ShandongChina State Key Laboratory of Offshore Oil Exploitation Beijing100028China CNOOC Research Institute Ltd. Beijing100028China CNPC Tarim Oilfield Branch Company Korla841000XinjiangChina National Engineering Laboratory for Exploration and Development of Low-Permeability Oil and Gas Fields Xi'an710000ShaanxiChina Sinopec Matrix Co. LTDQingdao266000ShandongChina

To assess whether a development strategy will be profitable enough,production forecasting is a crucial and difficult step in the *** development history of other reservoirs in the same class tends to be studied to make predictions ***,the permeability field,well patterns,and development regime must all be similar for two reservoirs to be considered in the same *** results in very few available experiences from other reservoirs even though there is a lot of historical information on numerous reservoirs because it is difficult to find such similar *** paper proposes a learn-to-learn method,which can better utilize a vast amount of historical data from various ***,the proposed method first learns how to learn samples before directly learning rules in ***,by utilizing gradients from networks with independent parameters and copied structure in each class of reservoirs,the proposed network obtains the optimal shared initial parameters which are regarded as transferable information across different *** on that,the network is able to predict future production indices for the target reservoir by only training with very limited samples collected from reservoirs in the same *** cases further demonstrate its superiority in accuracy to other widely-used network methods.

关键词： Production forecasting Multiple patterns Few-shot learning Transfer learning

Vortex identification based on the Liutex method and its effect on fish passage upstream

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Journal of Hydrodynamics 2024年第1期36卷 130-141页

作者： chun-ying Shen Rui-guo Yang Xiao-tao Shi ming-ming Wang Shi-hua He Faculty of Electrical Power Engineering Kunming University of Science and TechnologyKunming650500China Hubei International Science and Technology Cooperation Base of Fish Passage China Three Gorges UniversityYichang443002China Shanghai Investigation Design and Research Institute Co.LtShanghai200434China

Fishway research is important for mitigating the fragmentation of river habitats caused by hydraulic *** vertical slit fishway is a broadly used fishway type because of its high efficiency and adaptability to water ***,the resulting vortex current disrupts the fish passage hence directly affecting fish *** study aims to accurately capture the vortex structure in the fishway and analyze the effect of vortex elements(vortex structure,vortex intensity,etc.)on *** conducted an analysis of the 3-D current flow field in the fishway through the utilization of an experimental model and the large eddy simulation(LES)***,we captured the vortex information in the fishway at different flow rates using the Liutex vortex identification method and investigated the effect of the vortex on fish *** results revealed that the structures inside the fishway pool occupy most of the room,however,the areas with higher vortex strength were primarily located in the vortex near the vertical seam and the mainstream,the vortex strength inside the fishway gradually increases with increasing flow,suppressing fish *** experienced significantly increased resistance when encountering strong *** suggests that the vortex may act as a physical barrier to fish *** findings highlight the potential negative effects of vortex on fish movement and reiterate the importance of understanding vortex dynamics for aquatic environmental *** an effective tool for identifying vortices in fluid flow,the Liutex method demonstrates features of vortex within the fishway,thereby providing important insights into the interaction between fluid dynamics and aquatic organisms.

关键词： Vertical slit fishway vortex identification method Liutex large eddy simulation(LES) fish experiment computational fluid dynamics