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钢筋混凝土梁受拉区钢纤维影响系数的概率分布与取值建议

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应用基础与工程科学学报 2024年第3期32卷 860-874页

作者：黄云超高丹盈朱海堂房栋丁冲华北水利水电大学水利学院河南郑州450046 郑州大学水利科学与工程学院河南郑州450002 河南工程学院土木工程学院河南郑州451191 郑州大学土木工程学院河南郑州450002

通过18根高强钢筋钢纤维混凝土梁和1根高强钢筋混凝土梁的受弯试验,研究了混凝土强度、钢筋强度、钢纤维体积率、钢纤维端部弯钩数量、钢纤维混凝土层厚比和纵筋配筋率对钢筋混凝土梁受弯承载力的影响,讨论了我国现行规范中反映钢纤维... 详细信息

通过18根高强钢筋钢纤维混凝土梁和1根高强钢筋混凝土梁的受弯试验,研究了混凝土强度、钢筋强度、钢纤维体积率、钢纤维端部弯钩数量、钢纤维混凝土层厚比和纵筋配筋率对钢筋混凝土梁受弯承载力的影响,讨论了我国现行规范中反映钢纤维对梁受弯承载力影响的系数值用于计算高强钢筋钢纤维混凝土梁受弯承载力的适用性.结果表明,掺入钢纤维可有效提高高强钢筋混凝土梁的受弯承载力;与我国现行规范中钢纤维影响系数值相比,高强钢筋钢纤维混凝土梁受拉区钢纤维影响系数值偏小;在此基础上,通过收集国内外文献中相关的试验数据,重点分析了钢纤维影响系数的概率分布,得到不同保证率下的钢纤维影响系数值,提出了钢筋钢纤维混凝土梁受拉区钢纤维影响系数值的取值建议,可为我国规范的修订提供参考.

关键词：高强钢筋钢纤维混凝土梁受弯承载力影响系数概率分布保证率

不同频率重复脉冲与短阵快速脉冲经颅磁刺激对小鼠记忆功能和神经元兴奋性影响的对比分析

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生物医学工程学杂志 2024年第5期41卷 935-944页

作者：付蕊朱海军丁冲徐桂芝河北工业大学河北省生物电磁与神经工程重点实验室天津300130 河北工业大学省部共建电工装备可靠性与智能化国家重点实验室天津300130 河北大学河北省数字医疗工程重点实验室河北保定071002

经颅磁刺激(TMS)作为一种无创的神经调控技术现已用于神经和精神类疾病的临床治疗,但不同频率与模式TMS的刺激效果及其神经调控机制尚未明确。本文从神经电生理角度探究不同频率重复TMS(rTMS)和短阵快速脉冲TMS(bTMS)对小鼠学习记忆和... 详细信息

经颅磁刺激(TMS)作为一种无创的神经调控技术现已用于神经和精神类疾病的临床治疗,但不同频率与模式TMS的刺激效果及其神经调控机制尚未明确。本文从神经电生理角度探究不同频率重复TMS(rTMS)和短阵快速脉冲TMS(bTMS)对小鼠学习记忆和神经元兴奋性的影响。本文实验采用8周的昆明小鼠42只,随机分为伪刺激组和刺激组;刺激组包括:不同频率(1、5、10 Hz)的rTMS刺激组;不同频率(1、5、10 Hz)的bTMS刺激组。其中,刺激组接受连续14 d的刺激。刺激结束后,小鼠进行新物体识别与跳台实验以检测小鼠记忆能力;随后进行脑片膜片钳实验分析小鼠海马齿状回(DG)颗粒细胞兴奋性。结果表明,与伪刺激组相比,高频(5、10 Hz)的rTMS与bTMS能提高小鼠记忆能力和神经元兴奋性,而低频(1 Hz)的rTMS与bTMS则无显著效果;同频率下两种刺激模式对小鼠记忆功能与神经元兴奋性的影响无明显差别。本文研究结果提示,高频TMS可通过提高海马DG颗粒神经元兴奋性来提高小鼠记忆功能。本文为TMS改善认知功能的机制研究和临床应用提供实验和理论依据。

关键词：经颅磁刺激新物体识别跳台实验颗粒细胞脑片膜片钳实验神经元兴奋性

复合频率刺激对后肢去负荷小鼠海马齿状回区颗粒神经元作用的电生理研究

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生物化学与生物物理进展 2024年第7期51卷 1670-1686页

作者：赵峻峤朱明强朱海军付蕊张泽王佳乐丁冲河北工业大学生命科学与健康工程学院天津300130 河北省生物电磁与神经工程重点实验室(河北工业大学) 天津300130 省部共建电工装备可靠性与智能化国家重点实验室(河北工业大学) 天津300130 河北省数字医疗工程重点实验室(河北大学) 保定071002

目的近年来,失重环境对航天员神经系统造成的负面影响受到广泛关注。重复经颅磁刺激(repetitive transcranial magnetic stimulation,rTMS)技术对神经、精神类疾病的治疗效果有着显著积极影响。复合频率(不同频率刺激模式组成)的rTMS对... 详细信息

目的近年来,失重环境对航天员神经系统造成的负面影响受到广泛关注。重复经颅磁刺激(repetitive transcranial magnetic stimulation,rTMS)技术对神经、精神类疾病的治疗效果有着显著积极影响。复合频率(不同频率刺激模式组成)的rTMS对由失重环境引起的神经系统功能障碍的改善作用仍有待深入研究。探索复合频率刺激(combined frequency stimulation,CFS)对失重环境造成的多种神经系统疾病的治疗效果以及电生理机制,对于脑科学及磁刺激的临床应用具有重要意义。方法本研究采用40只C57BL/6小鼠,所有小鼠随机分为5组:假刺激组、后肢去负荷(HU)组、10 Hz组、20 Hz组和CFS(10 Hz+20 Hz,CFS)组。对除sham组以外的小鼠建立维持14 d的模拟失重效应并同期进行14 d的rTMS。通过蔗糖偏好实验和水迷宫实验验证CFS对负性情绪和空间认知能力的改善效果。最后,通过膜片钳技术记录海马齿状回(dentate gyrus,DG)颗粒神经元的动作电位、静息膜电位以及离子通道的动力学特性。结果行为学结果表明,CFS(10 Hz+20 Hz)显著改善了模拟失重小鼠的认知障碍和负性情绪;电生理实验结果显示,HU操作后小鼠海马DG区颗粒神经元的兴奋性降低,而CFS显著提高了神经元的兴奋性并改善了电压门控Na^(+)、K^(+)通道的动力学特性。结论复合频率的rTMS(10 Hz+20 Hz)能够有效地改善模拟失重小鼠的认知障碍和负面情绪,这种改善可能与CFS对神经元兴奋性以及Na^(+)、K^(+)通道动力学特性的影响有关。因此,本文有望为CFS改善失重环境下所产生的空间认知和负性情绪障碍提供理论依据。

关键词：复合频率刺激重复经颅磁刺激后肢去负荷空间认知障碍负性情绪神经元兴奋性离子通道

外周血miRNA-126与miRNA-143表达对颅内动脉瘤介入术后患者复发的预测价值

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川北医学院学报 2024年第1期39卷 22-25页

作者：丁崇学李扬罗坤新疆医科大学第一附属医院神经外三科新疆乌鲁木齐830000

目的:探讨外周血微小RNA-126(miRNA-126)、miRNA-143表达水平对颅内动脉瘤介入术后患者复发的预测价值。方法:选取113例行介入栓塞术治疗的颅内动脉瘤患者为研究对象,根据术后不同Raymond分级分为RaymondⅠ级组(n=88)、RaymondⅡ级组(n=... 详细信息

目的:探讨外周血微小RNA-126(miRNA-126)、miRNA-143表达水平对颅内动脉瘤介入术后患者复发的预测价值。方法:选取113例行介入栓塞术治疗的颅内动脉瘤患者为研究对象,根据术后不同Raymond分级分为RaymondⅠ级组(n=88)、RaymondⅡ级组(n=13)和RaymondⅢ组(n=12);根据不同预后分为复发组(n=19)和未复发组(n=94)。比较不同分级患者、不同预后患者外周血miRNA-126、miRNA-143表达水平,分析其与Raymond分级的相关性及其对颅内动脉瘤患者介入栓塞术后复发的预测价值。结果:与RaymondⅠ级组相比,RaymondⅡ级组和RaymondⅢ级组患者miRNA-126表达水平均升高(P<0.05),miRNA-143表达水平均降低(P<0.05)。相关性分析显示,miRNA-126水平与Raymond分级正相关(r=0.364,P<0.05),miRNA-143水平与Raymond分级负相关(r=-0.347,P<0.05)。复发组患者外周血miRNA-126表达水平高于未复发组(P<0.05),miRNA-143表达水平低于未复发组(P<0.05)。ROC曲线分析显示,外周血miR-126、miR-143及其联合预测颅内动脉瘤患者介入栓塞术后复发的曲线下面积分别为0.767、0.826、0.968,联合检测预测的价值高于两者单独预测(P<0.05)。结论:外周血miRNA-126、miRNA-143联合检测能提高颅内动脉瘤介入术后复发的预测价值。

关键词：颅内动脉瘤介入术复发微小RNA-126 微小RNA-143

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Synthesis and Characterization of Disodium Hydrogen Phosphate Dodecahydrate-Lauric-Palmitic Acid Used for Indoor Energy Storage Floor Units

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Journal of Thermal Science 2020年第2期29卷 477-485页

作者： XU Qian AKKURT Nevzat ZOU Zhenwei LIU Yang FENG Junxiao YU Chuqiao ding chong XIONG Yaxuan ZHOU Jingzhi ZANG Yong ding Yulong School of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083China Department of Mechanical Engineering Munzur UniversityTunceli 62000Turkey School of Information and Electronics Communication and Information SystemBeijing Institute of TechnologyBeijing 100081China School of Mathematics Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of HVAC Beijing University of Civil Engineering and ArchitectureBeijing 100044China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China

Organic and inorganic phase change materials(PCMs) are considered potential materials for thermal energy storage(TES) with different phase change characteristics. In this study, a novel organic-inorganic composite phase change material(PCM) called disodium hydrogen phosphate dodecahydrate-lauric-palmitic acid(D-LA-PACM) was prepared. Expanded graphite(EG) was selected as the support material, and the novel organic-inorganic form-stable PCM called D-LA-PAPCM/EG was prepared using the vacuum adsorption method. Differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, leakage testing, melting and solidification cycle testing, thermal conductivity testing, scanning electron microscopy observation of the micromorphology, and other characterization methods were used to study the microstructure and morphology, thermal physical parameters, thermal conductivity, stability of the PCMs, and the comprehensive material properties of D-LA-PAPCM under the composite action of EG. Results indicated that the melting and freezing temperatures and latent heats of D-LA-PAPCM/EG were measured to be 31.6℃ and 34.3℃ and 142.9 and 142.8 J/g, respectively. Although some of the lauric-palmitic acid(LA-PA) and disodium hydrogen phosphate dodecahydrate(DHPD) separated in the multiple porous structures of EG after 1000 cycles, they could still absorb and release latent heats independently, with D-LA-PAPCM/EG still exhibiting good thermal stability. The thermal conductivity of D-LA-PAPCM/EG was 1.361 W/(m·K). Therefore, the material and thermal properties of the prepared D-LA-PAPCM/EG indicate that it could be well used as a feasible material for energy-saving phase change floor units in indoor TES systems.

关键词： organic-inorganic PCM form-stable PCM thermal property energy storage

An effective catalyst carrier SiO_(2):Enhancing catalytic and combustion properties of CuFe_(2)O_(4)on energetic components

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Defence Technology（防务技术） 2024年第2期32卷 383-392页

作者： Li ding chong Wan Suhang Chen Zhao Qin Kangzhen Xu School of Chemical Engineering/Xi'an Key Laboratory of Special Energy Materials Northwest UniversityXi'an710069China Xi’an Modern Chemistry Research Institute Xi'an710065China

To enhance the catalytic activity of copper ferrite(CuFe_(2)O_(4))nanoparticle and promote its application as combustion catalyst,a low-cost silicon dioxide(SiO_(2))carrier was employed to construct a novel CuFe_(2)O_(4)/SiO_(2)binary composites via solvothermal *** phase structure,morphology and catalytic activity of CuFe_(2)O_(4)/SiO_(2)composites were studied firstly,and thermal decomposition,combustion and safety performance of ammonium perchlorate(AP)and 1,3,5-trinitroperhydro-1,3,5-triazine(RDX)with it affecting were then systematically *** results show that CuFe_(2)O_(4)/SiO_(2)composite can remarkably either advance the decomposition peak temperature of AP and RDX,or reduce the apparent activation energy at their main decomposition ***,the flame propagation rate of RDX was promoted by about 2.73 times with SiO_(2)content of 3 wt%,and safety property of energetic component was also improved greatly,in which depressing the electrostatic discharge sensitivity of pure RDX by about 1.89 *** addition,the effective range of SiO_(2)carrier content in the binary catalyst is found to be 3 to 5 wt%.Therefore,SiO_(2)opens a new insight on the design of combustion catalyst carrier and will promote the application of CuFe_(2)O_(4)catalyst in solid propellant.

关键词： Copper ferrite Silicon dioxide Combustion catalyst Thermal decomposition Laser ignition

Novel twinned Al3Sc dendrites in as-casted Al-Sc alloy

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Rare Metals 2023年第3期42卷 838-843页

作者： Xing-Quan Wang Yu Wang Qian Jia Zhao-chong ding Jin-Jiang He Song-Xiao Hui State Key Laboratory of Nonferrous Metals and Processes GRIMAT Engineering Institute Co.Ltd.Beijing 101407China GRIKIN Advanced Material Co. Ltd. Beijing Technology Research Center for Sputtering Target Material Engineering of High Pure Metals

Al-Sc alloys with high Sc contents are served as sputtering targets for making high-performance piezoelectric *** micro structure of these alloys would affect the sputtering process and the final quality of the functional *** this study,the microstructure in as-c as ted Al-20%Sc(in atomic ratio)alloys is characterized and the feathery Al3Sc grains with twin relationships are reported for the first *** crystallographic features of twined structures and growth directions are quantitatively analyzed by electron backscatter diffraction(EBSD)technique.

关键词： Al3Sc alloys twin

Solidification path calculations of Al-Zn-Mg alloys in Al-rich corner

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China Foundry 2017年第5期14卷 443-448页

作者： Guang-wei Zhao chong ding Xin-sheng Gu Xi-Cong Ye Cai-hua Huang Ming-chun Gu Hubei Key Laboratory of Hydroelectric Machinery Design&Maintenance China Three Gorges UniversityYichang 443002China College of Mechanical and Power Engineering China Three Gorges UniversityYichang 443002China Luoyang Sunrui Titanium Precision Casting Co. LtdLuoyang 471000China Medical College China Three Gorges UniversityYichang 443002China

The solidification paths of Al-Zn-Mg alloys in the Al-rich corner were investigated. The thermodynamic data for the calculation are obtained by direct coupling with the CALPHAD software Thermo-Calc via its TQ6-interface and the COST2 database. The influences of the initial compositions and the extent of solid back diffusion on the solidification path were numerically investigated by sample calculation of the ternary Al-Zn-Mg alloys. The calculation results of solidification paths of the selected alloys: Al-Zn-3 Mg(in wt.%), Al-5 Zn-10 Mg, Al-2.5Zn-15Mg, Al-10Zn-20.5 Mg, Al-8Zn-25 Mg, were: L→(L+α-Al), L→(L+α-Al)→(L+α-Al+TAU), L→(L+α-Al)→(L+α-Al+Al Mg_β), L→(L+α-Al)→(L+α-Al+TAU)→(L+α-Al+TAU+Al Mg_β), L→(L+α-Al)→(L+α-Al+Al Mg_β)→(L+α-Al+TAU+Al Mg_β), respectively. The results show that the initial compositions and the extent of solid back diffusion have a great influence on solidification path, and the amounts of eutectic phase increase with the decrease of the solid back diffusion coefficient. The equilibrium solute partition coefficients for Zn and Mg in alloys are also calculated and their influence on micro-segregation in the primary solidification of Al-5Zn-10 Mg alloy is analyzed.

关键词： solidification path Al-Zn-Mg alloy thermo-Calc

Boosting Hydrogen Storage Performance of MgH_(2) by Oxygen Vacancy-Rich H-V_(2)O_(5) Nanosheet as an Excited H-Pump

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Nano-Micro Letters 2024年第8期16卷 398-416页

作者： Li Ren Yinghui Li Zi Li Xi Lin chong Lu Wenjiang ding Jianxin Zou National Engineering Research Center of Light Alloys Net Forming&State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Shanghai Engineering Research Center of Mg Materials and Applications&School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Center of Hydrogen Science Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Instrumental Analysis Center of SJTU Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China

MgH_(2) is a promising high-capacity solid-state hydrogen storage material,while its application is greatly hindered by the high desorption temperature and sluggish ***,intertwined 2D oxygen vacancy-rich V_(2)O_(5) nanosheets(H-V_(2)O_(5))are specifically designed and used as catalysts to improve the hydrogen storage properties of MgH_(2).The as-prepared MgH_(2)-H-V_(2)O_(5) composites exhibit low desorption temperatures(Tonset=185℃)with a hydrogen capacity of 6.54 wt%,fast kinetics(Ea=84.55±1.37 kJ mol^(-1) H_(2) for desorption),and long cycling ***,hydrogen absorption can be achieved at a temperature as low as 30℃ with a capacity of 2.38 wt%within 60 ***,the composites maintain a capacity retention rate of~99%after 100 cycles at 275℃.Experimental studies and theoretical calculations demonstrate that the in-situ formed VH_(2)/V catalysts,unique 2D structure of H-V_(2)O_(5) nanosheets,and abundant oxygen vacancies positively contribute to the improved hydrogen sorption ***,the existence of oxygen vacancies plays a double role,which could not only directly accelerate the hydrogen ab/de-sorption rate of MgH_(2),but also indirectly affect the activity of the catalytic phase VH_(2)/V,thereby further boosting the hydrogen storage performance of MgH_(2).This work highlights an oxygen vacancy excited“hydrogen pump”effect of VH_(2)/V on the hydrogen sorption of Mg/MgH_(2).The strategy developed here may pave a new way toward the development of oxygen vacancy-rich transition metal oxides catalyzed hydride systems.

关键词： Hydrogen storage MgH_(2) V_(2)O_(5)nanosheets Oxygen vacancies VH_(2)