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A novel efficient energy absorber with free inversion of a metal foam-filled circular tube

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 1-14页

作者： Jianxun zhang jinwen BAI State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi'an Jiaotong UniversityXi'an 710049China

In this paper, a novel efficient energy absorber with free inversion of a metal foam-filled circular tube(MFFCT) is designed, and the axial compressive behavior of the MFFCT under free inversion is studied analytically and numerically. The theoretical analysis reveals that the energy is mainly dissipated through the radial bending of the metal circular tube, the circumferential expansion of the metal circular tube, and the metal filled-foam compression. The principle of energy conservation is used to derive the theoretical formula for the minimum compressive force of the MFFCT over free inversion under axial loading. Furthermore, the free inversion deformation characteristics of the MFFCT are analyzed numerically. The theoretical steady values are found to be in good agreement with the results of the finite element(FE) analysis. The effects of the average diameter of the metal tube, the wall thickness of the metal tube, and the filled-foam strength on the free inversion deformation of the MFFCT are considered. It is observed that in the steady deformation stage, the load-carrying and energy-absorbing capacities of the MFFCT increase with the increase in the average diameter of the metal tube, the wall thickness of the metal tube, or the filled-foam strength. The specific energy absorption(SEA) of free inversion of the MFFCT is significantly higher than that of the metal tube alone.

关键词： metal foam-filled circular tube(MFFCT) free inversion load-carrying capacity energy absorption

Asymmetrically ligated single atomic nickel sites for efficient hydrogen peroxide electrosynthesis

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Nano Research 2024年第3期17卷 1094-1100页

作者： Xusheng Cheng jinwen Hu Wenzhe Shang Jingya Guo Cuncun Xin Songlin zhang Suchan Song Wei Liu Yantao Shi State Key laboratory of Fine Chemicals Frontier Science Center for Smart MaterialsSchool of ChemistryDalian University of TechnologyDalian 116024China

Atomic transition-metal-nitrogen-carbon electrocatalysts hold great promise as alternatives to benchmark Pt in the oxygen reduction *** pristine metal centers with quasi square-planar D_(4h) configuration,however,still suffer from unfavorable energetics and thereby strong activity/selectivity trade-off during the catalytic *** we present a ligand-field engineering of single-atom Ni-N-C catalysts to boost the sluggish kinetics via rationally constructing prototypical asymmetrically ligated Ni-N_(3)O_(1) *** as-obtained Ni-supported multi-walled carbon nanotubes with molten salt-treated(defined as Ni/CNS)catalyst delivered an excellent H_(2)O_(2) selectivity(>90%)within a wide potential window(0.2–0.7 V *** hydrogen electrode(RHE))and robust stability(for 10 h)in alkaline *** electron paramagnetic resonance and theoretical analysis rationalize this finding and demonstrate that the broken symmetry facilitates the electron transfer of a σ* to O–O orbital as compared to the Ni-N_(4) counterpart,playing an indispensable role in efficient O_(2) activation.

关键词： broken D4h single nickel sites oxygen reduction H_(2)O_(2)production

Stability analysis of longwall top-coal caving face in extra-thick coal seams based on an innovative numerical hydraulic support model

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International Journal of Mining Science and Technology 2024年第4期34卷 491-505页

作者： Jun Guo Wenbo Huang Guorui Feng jinwen Bai Lirong Li Zi Wang Luyang Yu Xiaoze Wen Jie zhang Wenming Feng College of Mining Engineering Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Shanxi Province for Mine Rock Strata Control and Disaster Prevention Taiyuan University of TechnologyTaiyuan 030024China Shanxi Coking Coal Group Co. Ltd.Taiyuan 030024China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Taiyuan 030024China

The relationship between support and surrounding rock is of great significance to the control of surrounding rock in mining *** view of the fact that most of the existing numerical simulation methods construct virtual elements and stress servo control to approximately replace the hydraulic support problem,this paper establishes a new numerical model of hydraulic support with the same working characteristics as the actual hydraulic support by integrating numerical simulation software Rhino,Griddle and FLAC3D,which can realize the simulation of different working *** on this model,the influence mechanism of the supporting strength of hydraulic support on surrounding rock stress regulation and coal stability in front of the top coal caving face in extra thick coal seam were ***,under different support intensity,the abutment pressure of the bearing coal and the coal in front of it presents the “three-stage”evolution *** influence range of support intensity is 15%–30%.Secondly,1.5 MPa is the upper limit of impact that the support strength can have on the front coal failure ***,within a displacement range of 2.76 m from the coal wall,a support strength of1.5 MPa provides optimal control of the horizontal displacement of the coal.

关键词： Extremely thick coal seam Fully mechanized top coal caving Support strength Support-surrounding rock interaction

Unveiling structural evolution of Fe single atom catalyst in nitrate reduction for enhanced electrocatalytic ammonia synthesis

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Nano Research 2024年第8期17卷 6826-6832页

作者： Xusheng Cheng Wenzhe Shang Yuehui Li jinwen Hu Jingya Guo Dequan Cao Naitian zhang Songlin zhang Suchan Song Tianna Liu Wei Liu Yantao Shi State Key Laboratory of Fine Chemicals Frontier Science Center for Smart MaterialsSchool of ChemistryDalian University of TechnologyDalian 116024China

Atomic transition metal–nitrogen–carbon electrocatalysts exhibit outstanding activity in various electrocatalytic *** challenge lies in predicting the structure of the active center,which may undergo changes under applied potential and interact with reactants or *** characterization techniques,particularly in-situ X-ray absorption spectroscopy(XAS),provide crucial insights into the structural evolution of the metal active center during the *** this study,nitrate reduction to ammonia(NO_(3)RR)was selected as a model reaction,and we introduced in-situ XAS to reveal the structural evolution during the catalytic process.A novel single atom catalyst of iron loaded on three-dimensional nitrogen–carbon nanonetwork(designated as Fe SAC/NC)was successfully *** unraveled the structural transformations occurring as pyrrole-N_(4)-Fe transitions to pyrrole-N_(3)-Fe throughout the NO_(3)RR ***,the Fe SAC/NC catalyst exhibited excellent catalytic activity,achieving a Faradaic efficiency of 98.2% and an ammonia generation rate of 22,515μg·h^(−1)·mgcat−1 at−0.8 V versus reversible hydrogen *** calculations combined with in-situ spectroscopic characterization showed that pyrrole-N_(3)-Fe reduced the energy barrier from *NO to*NHO and improved the selectivity of *** provides a robust reference for the design of efficient nitrate-to-ammonia synthesis catalysts.

关键词： structural evolution Fe single atom catalysis in-situ X-ray absorption spectroscopy nitrate reduction to ammonia

Luteolin promotes neuronogenesis in hippocampus of chronic unpredictable mild stress rats and primary hippocampus of fetal rats

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Journal of Traditional Chinese Medicine 2024年第4期44卷 670-679页

作者： LIU Tongtong zhang Xi YANG Hui LIN Xiaoyuan LIU Jian zhang Xiuli GUO Dongwei ZHAO Hongqing ZOU Manshu LEI Chang LONG Hongping LUO Yan XIANG Yun GE jinwen WANG Yuhong MENG Pan Institute of Innovation and Applied Research in Chinese Medicine Hunan University of Chinese MedicineChangsha 410208China the Second People's Hospital of Hunan Province Changsha 410007China The First Affiliated Hospital Hunan University of Chinese MedicineChangsha 410007China Hunan Academy of Chinese Medicine Changsha 410013China

OBJECTIVE:To investigate the effects of luteolin on chronic unpredictable mild stress(CUMS)-induced depressive rats and corticosterone(CORT)-induced depressive primary hippocampal neurons,and to elucidate the mechanism behind the ***:The antidepressant mechanism of luteolin was studied by using CUMS rat model and primary hippocampal neurons in fetal *** vivo,novelty suppressed feeding,open-field and sucrose preference tests as well as Morris water maze were *** content of brain derived neurotrophic factor(BDNF),5-hydroxytryptamine(5-HT),norepinephrine(NE),and dopamine(DA)in serum were detected by enzyme-linked immunosorbent *** mechanisms of luteolin were explored based on neurotrophin and hippocampal neurogenesis,and *** of the septotemporal axis in hippocampus was assayed using the 5-bromo-2-deoxyuridine(Brdu),the expression of BDNF,neurotrophin-3(NT-3),and nerve growth factor(NGF)in hippocampus dentate gyrus region were measured by *** vitro,BDNF,NT-3,tropomyosin receptor kinase B(TrkB),and phosphorylated cyclic adenosine monophosphate responsive element binding protein(p-CREB)were detected through the high content analysis(HCA)to investigate neurotrophin and ***:Induction of CUMS in rats induced depressive symptoms,while luteolin significantly enhanced sucrose consumption,decreased feeding latency,increased locomotor activity,escape latency,distance of target quadrant and regulated the content of depressive-like *** analysis revealed that luteolin increased the abundance of new born neurons that had been labeled with Brdu,Brdu+neuronal nuclear antigen,and Brdu+doublecortin in septo-temporal axis of S2(mid-septal)and T3(mid-temporal).Moreover,expression of BDNF,NT-3,and NGF increased significantly in the septo-temporal axis of S2 and *** showed increased expression of BDNF,NT-3,TrkB and p-CREB in primary hippocampal ***:The results provided direct ev

关键词： fetal rats Survival

基于OVMD-HWOA-KELM模型的变压器油中溶解气体体积分数预测方法

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高电压技术 2024年第8期50卷 3793-3804,I0037,I0038,I0039页

作者：谢明浩张林鍹董小刚许晋闻新疆大学电气工程学院乌鲁木齐830047 清华大学国家计算机集成制造系统工程技术研究中心北京100084 国网陕西电力公司宝鸡供电公司宝鸡721000 国网陕西电力公司西安供电公司西安710000

针对变压器油中溶解气体序列波动性、随机性较强难以精确预测的问题,提出一种基于最优变分模态分解(optimal variational mode decomposition,OVMD)、混合型鲸鱼优化算法(hybrid whale optimization algorithm,HWOA)和核极限学习机(kern... 详细信息

针对变压器油中溶解气体序列波动性、随机性较强难以精确预测的问题,提出一种基于最优变分模态分解(optimal variational mode decomposition,OVMD)、混合型鲸鱼优化算法(hybrid whale optimization algorithm,HWOA)和核极限学习机(kernel extreme learning machine,KELM)的组合预测模型。首先,运用OVMD获取最优分解参数,并将原始序列分解为一系列相对平稳的分量;其次,通过在鲸鱼种群中融入混沌映射、非线性收敛参数、自适应权重因子和改进的算术优化算法提出HWOA算法,并利用测试函数验证HWOA算法的优越性;然后,对各分量分别构建KELM预测模型,使用HWOA优化KELM的关键参数。最后,将各分量的预测结果叠加重构,得到最终预测结果。案例分析表明,所提模型对变压器正常和异常案例预测的决定系数分别可达97.7%和93.46%,相较于现存方法,该模型具有更好的准确性和适应性,可为电力变压器运维管理提供有利技术支撑。

关键词：油中溶解气体最优变分模态分解融合型鲸鱼优化算法核极限学习机变压器状态预测

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中外信息公开标准比较研究

图书馆学研究 2024年第6期 39-49页

作者：霍亮张锦文郝杰张婷婷天津师范大学管理学院北京市西城区图书馆

信息公开标准对提升我国信息公开质量有着至关重要的作用。为了更好地完善我国信息公开标准化工作,有必要与发达国家进行对比研究。运用定量和定性方法对国外5个发达国家和我国信息公开相关标准在基本情况与制定过程方面进行对比。研究... 详细信息

信息公开标准对提升我国信息公开质量有着至关重要的作用。为了更好地完善我国信息公开标准化工作,有必要与发达国家进行对比研究。运用定量和定性方法对国外5个发达国家和我国信息公开相关标准在基本情况与制定过程方面进行对比。研究发现:我国信息公开标准体量略胜于国外;与国外标准相比,我国更注重政府信息公开的发展,对具体领域信息公开规范较少,对行业、企业的信息公开标准数量相对较少,管理要求内容宽泛。据此提出优化我国信息公开标准工作的建议。

关键词：文献计量标准文献内容对比信息公开

基于黄芩汤治疗结直肠癌作用机制的网络药理学和分子对接分析

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吉林大学学报（医学版） 2024年第1期50卷 208-220页

作者：陈霭莹姜靖雯张慧广州中医药大学附属海南中医院海南海口570100 海南省中医院肿瘤科海南海口570100

目的:通过网络药理学和分子对接技术分析黄芩汤治疗结直肠癌(CRC)的潜在作用靶点,阐明其相关分子机制。方法:基于中药系统药理学数据库与分析平台(TCMSP)构建黄芩汤活性成分和作用靶点数据集,通过GeneCards、人类在线孟德尔遗传(OMIM)... 详细信息

目的:通过网络药理学和分子对接技术分析黄芩汤治疗结直肠癌(CRC)的潜在作用靶点,阐明其相关分子机制。方法:基于中药系统药理学数据库与分析平台(TCMSP)构建黄芩汤活性成分和作用靶点数据集,通过GeneCards、人类在线孟德尔遗传(OMIM)、药物遗传学和药物基因组学知识库(PharmGKB)等数据库构建CRC疾病相关靶点数据集。利用R软件、Cytoscape软件和STRING数据库构建药物-疾病靶点交集、黄芩汤中药复方调控网络和蛋白-蛋白互作(PPI)网络。利用R软件和Metascape平台进行基因本体论(GO)功能富集分析和京都基因与基因组百科全书(KEGG)信号通路富集分析。采用AutoDock和PyMol软件进行分子对接验证,评估配受体结合情况。结果:筛选黄芩汤有效活性成分136个,黄芩汤治疗CRC的潜在靶点242个,核心靶点18个,基于信号通路分析获得CRC密切相关核心关键靶点5个,分别为蛋白激酶B1 (AKT1)、丝裂原活化蛋白激酶3 (MAPK3)、原癌基因FOS、肿瘤蛋白P53 (TP53)和原癌基因MYC。GO功能富集分析,主要参与多种细胞应激反应的生物过程。KEGG信号通路富集分析,潜在靶点在癌症通路高度富集;进一步对CRC核心靶点进行KEGG信号通路富集分析,主要涉及内分泌抵抗、细胞凋亡和表皮生长因子受体-酪氨酸激酶抑制剂(EGFR-TKI)抵抗等通路。分子对接验证,黄芩汤活性成分槲皮素、山柰酚、汉黄芩素、7-甲氧基-2-甲基异黄酮和柚皮素与AKT1、MAPK3、FOS、TP53及MYC均对接稳定,其中槲皮素与AKT1结合性最好。结论:黄芩汤活性成分可多靶点和多通路治疗CRC,核心配受体槲皮素和AKT1可能通过调控磷脂酰肌醇3-激酶(PI3K)/蛋白激酶B (AKT)和哺乳动物雷帕霉素靶蛋白(mTOR)信号通路影响细胞增殖、分化和凋亡进程,发挥治疗CRC作用。

关键词：黄芩汤网络药理学分子对接结直肠肿瘤槲皮素

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绝对进步与相对成长:一个学校效能评估框架

上海教育科研 2024年第3期 21-29页

作者：卢瑶罗靳雯张青根华中科技大学教育科学研究院 430074 美国加州大学洛杉矶分校教育与信息研究学院 90095

增值(VA)评价和学生成长百分等级(SGPs)评价均以学生的成长评估学校效能,但二者的评估理念、统计技术、评估结果又有明显不同。为此,基于绝对进步理念下的VA与相对成长理念下的SGPs构建为评估学校效能的新框架“VA-SGPs”。在新框架指导... 详细信息

增值(VA)评价和学生成长百分等级(SGPs)评价均以学生的成长评估学校效能,但二者的评估理念、统计技术、评估结果又有明显不同。为此,基于绝对进步理念下的VA与相对成长理念下的SGPs构建为评估学校效能的新框架“VA-SGPs”。在新框架指导下,基于中国教育追踪调查数据,采用OLS、HLM、SGPs模型研究发现:在学业成绩方面,超过70%学校在两种评估理念下的学校效能排名相差较大,且带给学生绝对进步较大的学校可能是带给学生相对成长较低的学校;在认知能力方面,超过40%学校在两种评估理念下的学校效能排名相差较大,认知能力上的高效能学校在学业成绩上可能是低效能学校。这说明新框架下的双维评估结果具有互补性,即双维评估理念具有发现非传统意义上“好学校”的潜力。

关键词：学校效能 VAM SGPs模型好学校