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Reducing agents for induction and maintenance therapy achieve long-term remission of refractory ulcerative colitis:A case report and review of literature
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作者 Pamela B Sylvestre 《World Journal of Gastroenterology》 2026年第2期152-161,共10页
BACKGROUND Ulcerative colitis(UC)is a chronic and debilitating inflammatory bowel disease.Cumulative evidence indicates that excess hydrogen peroxide,a potent neutrophilic chemotactic agent,produced by colonic epithel... BACKGROUND Ulcerative colitis(UC)is a chronic and debilitating inflammatory bowel disease.Cumulative evidence indicates that excess hydrogen peroxide,a potent neutrophilic chemotactic agent,produced by colonic epithelial cells has a causal role leading to infiltration of neutrophils into the colonic mucosa and subsequent development of UC.This evidence-based mechanism identifies hydrogen peroxide as a therapeutic target for reducing agents in the treatment of UC.CASE SUMMARY Presented is a 41-year-old female with a 26-year history of refractory UC.Having developed steroid dependence and never achieving complete remission on treatment by conventional and advanced therapies,she began treatment with oral R-dihydrolipoic acid(RDLA),a lipid-soluble reducing agent with intracellular site of action.Within a week,rectal bleeding ceased.She was asymptomatic for three years until a highly stressful experience,when she noticed blood in her stool.RDLA was discontinued,and she began treatment with oral sodium thiosulfate pentahydrate(STS),a reducing agent with extracellular site of action.After a week,rectal bleeding ceased,and she resumed oral RDLA and discontinued STS.To date,she remains asymptomatic with normal stool calprotectin while on RDLA.CONCLUSION STS and RDLA are reducing agents that serve as highly effective and safe therapy for the induction and maintenance of remission in UC,even in patients refractory or poorly controlled by conventional and advanced therapies.Should preliminary findings be validated by subsequent clinical trials,the use of reducing agents could potentially prevent thousands of colectomies and represent a paradigm shift in the treatment of UC. 展开更多
关键词 Ulcerative colitis COLITIS Inflammatory bowel disease Hydrogen peroxide Sodium thiosulfate R-dihydrolipoic acid reducing agent Redox homeostasis Reactive oxygen species Case report
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面向脚踝康复4-UCU/RRC并联机构的运动学分析及优化设计
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作者 李清 齐青华 任毅明 《机械科学与技术》 北大核心 2025年第9期1543-1548,共6页
针对踝关节损伤,基于4-UCU/RRC并联机构提出一种具有3R1T运动性能的踝关节康复机构。应用螺旋理论对其自由度进行分析,并采用封闭矢量法分析位置逆解。利用SolidWorks进行构型建模,并导入Adams中对其进行运动学仿真,分析仿真结果,曲线平... 针对踝关节损伤,基于4-UCU/RRC并联机构提出一种具有3R1T运动性能的踝关节康复机构。应用螺旋理论对其自由度进行分析,并采用封闭矢量法分析位置逆解。利用SolidWorks进行构型建模,并导入Adams中对其进行运动学仿真,分析仿真结果,曲线平滑,且没有断点及突变点,结果表明该踝关节康复机构安全性强,稳定性好。利用Ansys对该康复机构进行静力学仿真分析,并对该踝关节康复机构进行优化设计,使康复机构具有较强的承载能力,满足受损踝关节的康复需求。 展开更多
关键词 4-UCU/rrc 康复机构 踝关节 运动学 静力学
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基于数字化平台解决5G网络RRC频繁重建方案分析 被引量:1
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作者 杜娟 田阿灵 汪月 《山西电子技术》 2025年第4期66-68,共3页
目前我国5G网络规模全球领先。持续优化5G网络性能,提升用户体验,不断释放及提升5G价值是各大运营商的竞争点。5G网络无线资源建立频繁严重影响客户的使用感知,会造成话音不清晰、掉话、通话断续、上网慢等问题。基于数字化平台(CWR),按... 目前我国5G网络规模全球领先。持续优化5G网络性能,提升用户体验,不断释放及提升5G价值是各大运营商的竞争点。5G网络无线资源建立频繁严重影响客户的使用感知,会造成话音不清晰、掉话、通话断续、上网慢等问题。基于数字化平台(CWR),按照X板斧基本方法,深度分析无线资源控制(RRC)重建根因,结合场景化覆盖方案以及参数优化提升用户感知,降低RRC连接重建比,进而优化5G客户感知。 展开更多
关键词 rrc重建 数字化平台 感知
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Effect of sulfate-reducing bacteria on corrosion of copper and brass
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作者 Shu-hua XU Qin WANG +4 位作者 Zhuo-wei TAN Xiao-bao ZHOU Cong LI Zhen-sheng WANG Tang-qing WU 《Transactions of Nonferrous Metals Society of China》 2025年第6期1919-1936,共18页
The sulfate-reducing bacteria(SRB)corrosion of H70 brass,H80 brass and T2 copper was systematically studied using microstructure characterizations and electrochemical measurements.The results showed that H70 brass,H80... The sulfate-reducing bacteria(SRB)corrosion of H70 brass,H80 brass and T2 copper was systematically studied using microstructure characterizations and electrochemical measurements.The results showed that H70 brass,H80 brass and T2 copper exhibited good corrosion resistance in the sterile environment,and the corrosion products were mainly metal oxides,such as Cu_(2)O,CuO and ZnO.The SRB metabolism sharply accelerated the corrosion process of three types of copper alloys,especially the T2 copper.In the inoculated environment,an additional mixture of Cu_(2)S,ZnS and CuSO_(4)existed in the corrosion products.Pitting corrosion was the main corrosion style for the H70 brass and H80 brass,while general corrosion and pitting corrosion simultaneously dominated the corrosion process of the T2 copper in this environment.The results provide a new insight to the microbiological corrosion of copper alloys. 展开更多
关键词 COPPER BRASS sulfate reducing bacteria microbiologically influenced corrosion MICROSTRUCTURE
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Flash Calcination of Kaolinite Clay in a Pilot Reactor: Evaluation of Clay Color Change in Oxidizing, Inert and Reducing Atmospheres
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作者 Gabriel Henrique Wienhage Vinícius Henrique de Freitas +4 位作者 Julio Zeppone Carlos Luis Filipe von Rainer Fabiani Luiz Felipe de Pinho Rodrigo de Souza Borges Vinicyus Rodolfo Wiggers 《Journal of Building Material Science》 2025年第1期73-82,共10页
Cement production,while essential for global infrastructure,contributes significantly to carbon dioxide emissions,accounting for approximately 7%of total emissions.To mitigate these environmental impacts,flash calcina... Cement production,while essential for global infrastructure,contributes significantly to carbon dioxide emissions,accounting for approximately 7%of total emissions.To mitigate these environmental impacts,flash calcination of kaolinitic clays has been investigated as a sustainable alternative.This technique involves the rapid heating of clays,enabling their use as supplementary cementitious materials.The primary objective of this study was to modify the color of calcined clay in various atmospheres(oxidizing,inert,and reducing)to achieve a grayish tone similar to commercial cement while preserving its reactive properties.The experimental procedure employed a tubular reactor with precise control of gas flows(atmospheric air,nitrogen,and a carbon monoxide–nitrogen mixture).Physicochemical characterization of the raw clay was conducted before calcination,with analyses repeated on the calcined clays following experimentation.Results indicated that clay calcined in an oxidizing atmosphere acquired a reddish hue,attributed to the oxidation of iron in hematite.The Clay exhibited a pinkish tone in an inert atmosphere,while calcination in a reducing atmosphere yielded the desired grayish color.Regarding pozzolanic activity,clays calcined in oxidizing and inert atmospheres displayed robust strength,ranging from 82%to 87%.Calcination in a reducing atmosphere resulted in slightly lower strength,around 74%,likely due to the clay’s chemical composition and the calcination process,which affects compound formation and material reactivity. 展开更多
关键词 Flash Calcination Kaolinite Clay reducing Atmosphere Reduction of Hematite
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Reducing the magnitude and variability of seismic-induced acceleration and force responses in steel buildings with controlled rocking base mechanism and force-limiting connections
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作者 Georgios Tsampras Richard Sause 《Resilient Cities and Structures》 2025年第4期143-157,共15页
This study numerically investigates the seismic response of a nine-story self-centering concentrically braced frame building incorporating force-limiting connections between the floor system and the lateral force-resi... This study numerically investigates the seismic response of a nine-story self-centering concentrically braced frame building incorporating force-limiting connections between the floor system and the lateral force-resisting system.Nonlinear earthquake simulations are conducted under design basis earthquake ground motions,and the results are compared against a baseline model with rigid-elastic connections.The study discusses connection design considerations and evaluates the effectiveness of force-limiting connections in mitigating higher-mode effects.The findings show that force-limiting connections significantly reduce the magnitude and variability of floor accelerations,brace forces,and connection forces,while maintaining comparable story drifts.limiting Force-connections primarily reduce the contribution of higher-mode responses,while the controlled rocking base mechanism modifies the first-mode response.Overall,the reduced dispersion in structural response improves the reliability of seismic design and enhances resilience by minimizing damage to both structural components and acceleration-sensitive nonstructural elements. 展开更多
关键词 Force-limiting connections ROCKING SELF-CENTERING Steel concentrically braced frames Reduced variability Higher-mode effects
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Investigation on the reducing parameters of the Helmholtz energy equation of state for methane/methanol binary with VLE data
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作者 Xuehui Wang Dan Dan +2 位作者 Xinyue Hao Wei Lin Edward Wright 《Chinese Journal of Chemical Engineering》 2025年第7期160-170,共11页
Natural gas is widely regarded as an efficient,relatively clean,and economically viable energy source.Its safe operation and continuous supply through pipeline infrastructure has led to its prominence in the energy se... Natural gas is widely regarded as an efficient,relatively clean,and economically viable energy source.Its safe operation and continuous supply through pipeline infrastructure has led to its prominence in the energy sector.Methanol plays an important role in the natural gas industry,typically serving as a solvent or hydrate inhibitor.Therefore,the accurate estimation of thermodynamic properties for methane/methanol binary is extremely important to optimise the operating parameter,maximise the dehydration effect,and reduce the cost.As the Helmholtz energy equation of state is expected to offer high accuracy in predicting the vapour-liquid equilibrium of methane/methanol binary,four reducing parameters were derived based on collected experimental data.Additionally,the sensitivities of various reducing parameter combinations were simultaneously investigated.The results demonstrated a strong agreement between predicted fractions and experimental data,with the UMADs(uncertainty-weighted mean absolute deviation)of 3.484 and 0.665 for liquid and vapour phases,respectively.Meanwhile,it is deemed“very likely”,“likely”,and“unlikely”to achieve acceptable prediction for 3-parameter optimisation,2-parameter optimisation and,1-parameter optimisation,respectively. 展开更多
关键词 SOLUBILITY METHANE Vapour liquid equilibrium(VLE) Equation of state reducing parameters
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Reducing Stigma and Promoting Empowerment:A Pre-Post Evaluation of ACE-LYNX Intervention on the Mental Health Literacy of University Providers
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作者 Fenghua Wang Jianguo Gao +4 位作者 Zhi-Ying Yao Kenneth Po-Lun Fung Cun-Xian Jia Sheng-Li Cheng Josephine Pui-Hing Wong 《International Journal of Mental Health Promotion》 2025年第10期1497-1514,共18页
Background:Limited mental health literacy(MHL)among university service providers is a significant obstacle to effective psychological support.Developing and systematically assessing evidence-based interventions is an ... Background:Limited mental health literacy(MHL)among university service providers is a significant obstacle to effective psychological support.Developing and systematically assessing evidence-based interventions is an urgent priority,particularly in low-and middle-income countries(LMICs).This study aimed to evaluate the effectiveness of the Acceptance&Commitment to Empowerment:Linking Youths AND‘Xin’(Hearts)(ACE-LYNX)intervention in reducing stigma,improving psychological well-being,and enhancing the MHL and empowerment practices of university mental health providers in China.Methods:A total of 124 trained providers participated in this longitudinal study.Quantitative data were collected at baseline,immediately post-intervention,and three-month follow-up using the validated scale(CAMI,DASS-21)and weekly activity logs recording empowerment practices.Generalized estimating equations(GEEs)and qualitative content analysis were used for data analysis.Results:Quantitative analysis showed a significant reduction in stigma immediately postintervention,particularly in the Social Restriction subscale(β=1.35,p<0.001),though this effect diminished by the 3-month follow-up(β=1.80,p=0.001).Notably,a lasting reduction in the providers’stress levels was maintained.Activity logs showed the highest level of engagement at the individual level(51.4%),followed by group level(32.0%),organizational level(10.5%),and community level(6.1%).Qualitative analysis revealed three themes:Skill-based empowerment enhances professional efficacy,embedded interventions expand service boundaries,and organizational empowerment fosters sustainability.Conclusions:This dual-focus ACE-LYNX intervention effectively improved MHL and both attitudinal and functional competencies among providers.It provides a scalable framework for fostering sustainable and inclusive campus mental health ecosystems,with significant implication for enhance psychological services in resource-constrained educational settings. 展开更多
关键词 Mental health literacy(MHL) reduce stigma university service providers EMPOWERMENT
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Evaluating the global thiols redox state in living cells using a reducing sulfur species responsive fiuorescence switching platform
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作者 Hui Zhang Rong Feng +10 位作者 Wanyi Yu Hongbei Wei Tianhong Wu Peng Zhang Wenhai Bian Xin Li Di Gao Guojun Weng Zhe Yang Tony D.James Xiaolong Sun 《Chinese Chemical Letters》 2025年第4期338-344,共7页
Redox dyshomeostasis is a critical factor in the initiation of numerous diseases,making the accurate evaluation of the redox status of the cellular environment an important aspect of physiological research.However,mai... Redox dyshomeostasis is a critical factor in the initiation of numerous diseases,making the accurate evaluation of the redox status of the cellular environment an important aspect of physiological research.However,maintaining redox homeostasis relies on a complex and dynamic physiological system involving multiple substrate-enzyme interactions,so its accurately detection remains a challenge.With this research,we developed an activable fiuorescence switching platform by incorporating different conjugate acceptors to a fiuorophore using ester bonds and resulting in fiuorescence quenching due to donor-excited photo-induced electron transfer(d-Pe T),which was confirmed through density functional theory calculations.The reaction-based probe was deployed for recognizing all major intracellular reducing sulfur species(RSS),including H_(2)S,cysteine(Cys),homocysteine(Hcy),glutathione(GSH),and protein free thiols.The quenched fiuorescence was significantly recovered by RSS,through releasing the fiuorophore and diminishing the d-Pe T effect.Furthermore,the fiuorescent probe was used for the sensing and imaging RSS in living cells,demonstrating good cell-permeability,low cytotoxicity,and negative correlation with reactive oxygen species content,enabling the evaluating of global thiols redox state in Hep G2 cellular lines during ferroptosis processes. 展开更多
关键词 Fluorescent probe reducing sulfur species Donor-excited photo-induced electron transfer Thiols redox state Ferroptosis
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Correction: Silencing of the long non-coding RNA LINC00265triggers autophagy and apoptosis in lung cancer by reducingprotein stability of SIN3A oncogene
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作者 XIAOBI HUANG CHUNYUAN CHEN +9 位作者 YONGYANG CHEN HONGLIAN ZHOU YONGHUA CHEN ZHONG HUANG YULIU XIE BAIYANG LIU YUDONG GUO ZHIXIONG YANG GUANGHUA CHEN WENMEI SU 《Oncology Research》 2025年第5期1249-1250,共2页
In the article“Silencing of the long non-coding RNA LINC00265 triggers autophagy and apoptosis in lung cancer by reducing protein stability of SIN3A oncogene”(Oncology Research.2024,Vol.32,No.7,pp.1185–1195.doi:10.... In the article“Silencing of the long non-coding RNA LINC00265 triggers autophagy and apoptosis in lung cancer by reducing protein stability of SIN3A oncogene”(Oncology Research.2024,Vol.32,No.7,pp.1185–1195.doi:10.32604/or.2023.030771,https://www.techscience.com/or/v32n7/57163),an inadvertent error occurred during the compilation of Fig.3H.This needed corrections to ensure the accuracy and integrity of the data presented. 展开更多
关键词 lung cancer long non coding RNA reducing protein stability sin oncogene oncology AUTOPHAGY protein stability APOPTOSIS accuracy integrity SILENCING
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关闭煤矿采空区矿井水水质演化与硫酸盐去除的微生物作用机制
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作者 孙亚军 郭娟 +7 位作者 张莉 徐智敏 何环 张雯 华景帆 雷江青 郇博程 刘嘉欣 《煤炭学报》 北大核心 2026年第1期576-590,共15页
近年来,我国煤矿关闭数量逐渐增多,废弃矿井采空区成为潜在地下水污染源,以高硫酸盐矿井水为主要特征。采空区内原生微生物群落在一定条件下可驱动硫循环,激发采空区矿井水硫酸盐自然削减的潜力。为探究关闭煤矿采空区矿井水水质演化控... 近年来,我国煤矿关闭数量逐渐增多,废弃矿井采空区成为潜在地下水污染源,以高硫酸盐矿井水为主要特征。采空区内原生微生物群落在一定条件下可驱动硫循环,激发采空区矿井水硫酸盐自然削减的潜力。为探究关闭煤矿采空区矿井水水质演化控制机理及硫酸盐去除的微生物机制,以西北典型煤矿为研究对象,通过设计5种不同条件下的长期室内微宇宙试验(试验组、煤多组、加培养基组、加培养基和微生物组、灭菌组),利用水化学测试、16S rDNA高通量测序等测试手段,系统探究了矿井水硫酸盐去除的水化学特征与微生物作用机制。水化学特征研究结果表明:试验组与煤多组体系内的SO_(4)^(2-)含量先升后降,加培养基组SO_(4)^(2-)含量降低96%,加培养基和微生物组SO_(4)^(2-)含量降低95%,灭菌组SO_(4)^(2-)含量降低57%,水化学指标说明在保持无氧并提供可利用碳源情况下,关闭煤矿采空区具备实现矿井水中硫酸盐低成本生物去除的潜力。微生物测序研究结果表明:外源微生物可能破坏土著微生物生态代谢网络,采空区体系中存在降解煤中大分子有机物的菌属,与硫酸盐还原菌形成协同体系,3组(加培养基组、加培养基和微生物组、灭菌组)硫酸盐还原菌相对丰度显著升高,最高可达70.1%、79%,说明微生物还原过程是控制硫酸盐去除的关键。根据上述研究成果,阐明了关闭煤矿采空区矿井水水质演化机制:在无外源小分子碳源条件下,土著SRB处于低活性或休眠状态,采空区矿井水水质演化由黄铁矿氧化、矿物溶解及黏土矿物吸附等水化学作用所主导;而添加外源碳源后,微生物作用成为主要控制因素;碳源的类型与质量浓度决定了关闭煤矿采空区矿井水水质演化过程水化学场−微生物场相互转化、相互耦合的方向。若能驯化或富集具有煤有机质降解能力的土著菌群,可实现矿井水低成本处理。 展开更多
关键词 关闭煤矿 硫酸盐去除 硫酸盐还原菌 微生物还原 碳源
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基于地理探测器的涑水河流域耕作方式对土壤有机碳的影响
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作者 荆颖蔷 毕如田 +2 位作者 孙维峰 朱洪芬 张秀娟 《中国野生植物资源》 2026年第1期67-74,共8页
目的:明确区域土壤有机碳(SOC)动态变化的主导驱动因素,为制定科学的农田固碳增效管理策略提供依据。方法:于2022~2023年小麦-玉米轮作周期内,在涑水河流域对36个固定样点进行3次采样,结合地理探测器方法,分析耕作方式与气候、地形、土... 目的:明确区域土壤有机碳(SOC)动态变化的主导驱动因素,为制定科学的农田固碳增效管理策略提供依据。方法:于2022~2023年小麦-玉米轮作周期内,在涑水河流域对36个固定样点进行3次采样,结合地理探测器方法,分析耕作方式与气候、地形、土壤属性等因子的交互作用对SOC时空变化的影响。结果:SOC含量呈现显著作物差异,小麦收获期[(12.74±3.21)g/kg]较玉米收获期[(9.75±3.25)g/kg]高,而两季小麦收获期SOC保持稳定。耕作方式对收获期SOC及生长期SOC变化的影响均达到显著性水平(P<0.1),与气候、地形、土壤属性和其他管理措施等因子交互后的解释力显著提升(15%-85%)。免耕种植玉米、少耕种植小麦可以显著提升收获期的SOC含量,也优化了生长期内SOC的变化,免耕种植玉米结合少耕种植小麦显著提升了全年土壤固碳量(1.28 g/kg)。结论:耕作方式是调控SOC动态的核心要素,免耕、少耕通过减弱土壤扰动展现出显著的固碳潜力,建议结合区域环境因子进行耕作管理方式的优化,以实现农田固碳增效。 展开更多
关键词 免耕 少耕 土壤有机碳 地理探测器
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还原铁粉对工业硅炉底料碳化硅物相转变机理研究
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作者 张少博 陈正杰 +3 位作者 张永航 胡议友 罗喷 马文会 《昆明理工大学学报(自然科学版)》 北大核心 2026年第1期1-13,共13页
在工业硅冶炼过程中矿热炉内会产生大量的炉底料,为了解决炉底料引起的炉底上涨、设备损坏等问题,采用加铁粉的方法以去除炉底料中的碳化硅.结果表明:通过加入铁粉焙烧,可以使SiC转变成Fe3Si.加铁焙烧的最佳条件:还原铁粉添加量为3 g,... 在工业硅冶炼过程中矿热炉内会产生大量的炉底料,为了解决炉底料引起的炉底上涨、设备损坏等问题,采用加铁粉的方法以去除炉底料中的碳化硅.结果表明:通过加入铁粉焙烧,可以使SiC转变成Fe3Si.加铁焙烧的最佳条件:还原铁粉添加量为3 g,熔炼温度为1400℃,焙烧时间为60 min.当温度高于1400℃时,焙烧产物会生成线状的SiC,并且随温度的升高越来越多.添加剂中的Fe最终以Fe3Si的形式存在于所得产物中,并且在产品的表面可清晰地检测到规则的球形.同时从微观表征中发现:随着加铁量增大,产物中会检测到单质碳,这是因为铁将碳化硅中的碳元素还原成了单质碳.综合分析表明,该实验结果可为解决炉底料引起的问题提供思路,对其后续增值利用提供技术支持. 展开更多
关键词 工业硅炉 炉底料 碳化硅 还原铁粉
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危机转化视角下中国省际碳排放与经济发展的脱钩“链式”反应分析
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作者 杨青 段召琳 +3 位作者 刘星星 陈英杰 吴婵媛 汪金美 《环境科学》 北大核心 2026年第2期727-740,共14页
碳排放与经济发展脱钩是实现“双碳”目标的重要抓手,但脱钩状态的不稳定迫使地区低碳发展极易陷入“增碳减效”(强负脱钩)和“强增碳弱增效”(增长负脱钩)的双重“危机”.因此,基于Tapio模型分析2010~2021年中国30个省(区、市)碳排放... 碳排放与经济发展脱钩是实现“双碳”目标的重要抓手,但脱钩状态的不稳定迫使地区低碳发展极易陷入“增碳减效”(强负脱钩)和“强增碳弱增效”(增长负脱钩)的双重“危机”.因此,基于Tapio模型分析2010~2021年中国30个省(区、市)碳排放脱钩状态的时空演变特征,构建碳排放脱钩危机转化评价模型,探讨碳脱钩状态是否向好转变的链式反应特征.结果发现:①中国碳脱钩进程虽整体向好,但暴露出高碳依赖模式的系统性风险,部分地区通过危机倒逼机制成功突破路径锁定,形成“低碳突围”示范效应,验证了危机驱动的转型可行性;②碳排放脱钩的危机转化效能存在“半程困境”(转化率为40%~50%),既反映传统发展惯性的持续阻力,也揭示区域分化背后的政策响应差异;③脱钩状态的“链式跃迁”特征表明,危机转化具有“风险解构-要素重置-发展转型”的动态累积效应;④能源强度的核心驱动作用与单位能耗碳排放的积极作用,凸显驱动危机转化的双重路径,短期依赖强度调控可能加剧波动风险,而效率提升才是化解“减排-增长”矛盾的系统性解方. 展开更多
关键词 碳排放 脱钩 危机转化 马尔可夫链 减碳增效
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基于设计载荷谱的纯电动乘用车减速器壳体疲劳寿命分析
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作者 邹喜红 周振 +3 位作者 周雨航 袁冬梅 熊锋 杨皓理 《兵器装备工程学报》 北大核心 2026年第2期17-23,共7页
针对某型纯电动乘用车减速器壳体疲劳寿命分析,存在开发周期长、预测结果差等问题,提出了一种基于设计载荷谱的某型纯电动乘用车减速器壳体疲劳寿命分析方法。本文利用采集减速器实测载荷谱,采用雨流计数法获取载荷谱均幅值频次分布,采... 针对某型纯电动乘用车减速器壳体疲劳寿命分析,存在开发周期长、预测结果差等问题,提出了一种基于设计载荷谱的某型纯电动乘用车减速器壳体疲劳寿命分析方法。本文利用采集减速器实测载荷谱,采用雨流计数法获取载荷谱均幅值频次分布,采用威布尔分布模型和正态分布模型分别对幅值与均值进行检验,并用参数法外推获得全寿命周期,以此推断恶劣工况极大载荷值,采用雨流矩阵模拟法获取时域重构设计载荷谱。在此基础上,建立减速器有限元模型,并基于实测载荷谱进行模型验证,分别在实测载荷谱和设计载荷谱2种载荷作用下,进行仿真分析,采用名义应力法,结合线性累积损伤理论和修正材料的S-N曲线对壳体进行疲劳寿命分析。结果表明,实测载荷谱和设计载荷谱作用下减速器壳体的损伤值相差较小,在保留计算精度的情况下,设计载荷谱能极大缩短减速器疲劳开发周期。 展开更多
关键词 某型纯电动乘用车 减速器壳体 设计载荷谱 疲劳寿命
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亚铁离子对硫酸盐还原菌腐蚀行为的影响
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作者 张雅妮 段博文 +3 位作者 宋伟 张成鑫 樊冰 王思敏 《材料导报》 北大核心 2026年第5期225-233,共9页
亚铁离子(Fe^(2+))对SRB的生长和对碳钢的MIC起重要作用。本工作通过生物培养技术、浸泡实验、电化学等实验方法,结合Na_(2)S_(2)O_(3)滴定技术、扫描电镜(SEM)、X射线光电子能谱(XPS)、激光共聚焦等分析手段,研究了Fe^(2+)对硫酸盐还... 亚铁离子(Fe^(2+))对SRB的生长和对碳钢的MIC起重要作用。本工作通过生物培养技术、浸泡实验、电化学等实验方法,结合Na_(2)S_(2)O_(3)滴定技术、扫描电镜(SEM)、X射线光电子能谱(XPS)、激光共聚焦等分析手段,研究了Fe^(2+)对硫酸盐还原菌环境中X80管线钢腐蚀行为的影响,包含SRB数量的变化、硫离子含量及价态的变化、表面生物膜的特征,截面形貌、腐蚀速率及电化学过程特征。结果表明:Fe^(2+)浓度为5 g/L时,Fe^(2+)促进SRB的生长,延长SRB的生命周期,峰值SRB数量为5.15×10^(7)cm^(-3);但高浓度Fe^(2+)(≥10 g/L)抑制了SRB的生长,缩短SRB的生命周期。对于SRB腐蚀,在低浓度Fe^(2+)环境中,初期腐蚀速率由Fe^(2+)对基体表面的活化和对SRB的活性促进共同决定,中后期由致密的SRB膜层决定,因此X80钢腐蚀速率随暴露时间的延长先增加后降低。在高浓度Fe^(2+)环境中,初期腐蚀速率由Fe^(2+)对基体表面的活化和低活性SRB共同决定,中后期由多裂隙混生膜层决定,腐蚀速率随暴露时间的延长持续增加。20 d后,随溶液中Fe^(2+)浓度的增加,X80钢的点蚀速率和平均失重速率同步增长,当Fe^(2+)浓度为40 g/L时,最大平均失重速率为0.1024 mm/a。 展开更多
关键词 硫酸盐还原菌 亚铁离子 X80钢 腐蚀
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黏重土壤芯铧式播种开沟器优化设计与试验
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作者 郝建军 屈鹏程 +4 位作者 刘天龙 赵佳乐 殷常峰 赵建国 王新芳 《农业机械学报》 北大核心 2026年第1期180-190,226,共12页
针对播种开沟器在黏重土壤环境下作业时粘土严重、开沟阻力大等问题,本文设计了一种适宜黏重土壤的芯铧式播种开沟器。通过理论分析与经验设计,确定了芯铧式播种开沟器的结构参数为:入土角45°、入土隙角5°、斜切角30°、... 针对播种开沟器在黏重土壤环境下作业时粘土严重、开沟阻力大等问题,本文设计了一种适宜黏重土壤的芯铧式播种开沟器。通过理论分析与经验设计,确定了芯铧式播种开沟器的结构参数为:入土角45°、入土隙角5°、斜切角30°、起始滑切角23°、终止滑切角45°、芯铧幅宽45 mm。为进一步改善黏重土壤环境下芯铧式播种开沟器减粘脱附性能,基于仿生学的非光滑表面减粘降阻原理,采用增加凸筋方式对芯铧式播种开沟器犁体表面局部进行织构化改形设计,以凸筋几何参数为试验因素,利用EDEM软件模拟开沟器在土槽中的运动情况,采用响应面试验分析凸筋几何参数对土壤粘附量和开沟阻力的影响规律,优化凸筋几何参数最佳组合为:凸筋宽度7.623 mm、凸筋高度1.344 mm、相邻凸筋间距11.782 mm,此时开沟器土壤粘附量为159.88 g,开沟阻力为60.065 N。土槽试验结果表明:在相同工作条件下,织构化改形开沟器较普通开沟器土壤减粘率为16.33%,开沟阻力降低了2.91%~4.45%,达到了预期的减粘降阻效果。 展开更多
关键词 播种机 芯铧式开沟器 黏重土壤 EDEM 减粘降阻 优化设计
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耐温聚合物减阻剂的制备及耐温滑溜水的减阻机制
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作者 赵明伟 杨子腾 +2 位作者 马振峰 徐忠正 戴彩丽 《中国石油大学学报(自然科学版)》 北大核心 2026年第1期185-195,共11页
针对常规滑溜水压裂液耐温性不足等问题,通过自由基聚合法合成一种适用于深层页岩储层油气开发的耐温聚合物减阻剂YTRP,利用红外光谱等手段对其结构进行表征,并以YTRP为压裂液主剂构筑耐温滑溜水压裂液体系,对体系的综合性能进行评价,... 针对常规滑溜水压裂液耐温性不足等问题,通过自由基聚合法合成一种适用于深层页岩储层油气开发的耐温聚合物减阻剂YTRP,利用红外光谱等手段对其结构进行表征,并以YTRP为压裂液主剂构筑耐温滑溜水压裂液体系,对体系的综合性能进行评价,借助流变试验与微观表征揭示YTRP减阻剂减阻机制。结果表明:相较于相同相对分子质量的部分水解聚丙烯酰胺HPAM,耐温滑溜水体系具有更优异的耐温耐剪切性、配伍性,在高温条件下减阻性能优异(120℃时减阻率为72.6%),储层伤害性低(岩心伤害率为11.72%),防膨性能好(CST比值为1.01);相较于HPAM,YTRP分子柔顺性更好,经历高温环境后保留的结构强度更高;通过聚合物减阻剂的黏性与弹性协同增效,聚合物链形成的网络结构在与湍流相互作用的过程中,能够有效实现能量的储存与释放,降低能量损耗,达到高温下更好的减阻效果。 展开更多
关键词 耐温减阻剂 流变 低伤害 减阻性能 减阻机制
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近红外光谱技术快速检测烟草花中主要活性成分含量的研究
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作者 付秋娟 许明磊 +6 位作者 张忠锋 黄择祥 谭效磊 侯小东 韩晓 孙婷婷 孟凡超 《中国烟草科学》 北大核心 2026年第1期116-123,共8页
为了实现对烟草花中主要活性成分(还原糖、总黄酮、绿原酸、芸香苷和西柏三烯二醇)的快速无损检测,以全国196份不同产地、不同品种的烟草花为研究对象,采用近红外光谱技术建立了5种活性成分的分析模型。通过筛选光谱预处理方法,优化谱... 为了实现对烟草花中主要活性成分(还原糖、总黄酮、绿原酸、芸香苷和西柏三烯二醇)的快速无损检测,以全国196份不同产地、不同品种的烟草花为研究对象,采用近红外光谱技术建立了5种活性成分的分析模型。通过筛选光谱预处理方法,优化谱区范围和主成分数,进一步提升了模型性能。利用内部交叉验证,得到了各成分的最优模型。结果表明:还原糖、总黄酮、绿原酸、芸香苷和西柏三烯二醇5种活性成分的近红外校正模型中,校正集相关系数(R_(c))为0.957~0.986,校正均方根误差(RMSEC)为0.025%~0.995%;交叉验证相关系数(R_(cv))为0.901~0.979,交叉验证均方根误差(RMSECV)为0.030%~1.350%。外部验证结果显示,5种活性成分模型的相对标准偏差(RSD)均小于10%,且t检验表明,近红外光谱法预测值与传统化学分析值之间无显著差异。这表明该方法具有较高的准确性和可靠性,能够快速无损地检测烟草花中5种主要活性成分,为烟草花的高效开发利用提供了技术支撑。 展开更多
关键词 烟草花 近红外 还原糖 总黄酮 绿原酸 芸香苷 西柏三烯二醇
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层电荷对膨润土收缩行为影响的试验和理论研究
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作者 马田田 刘亭利 +2 位作者 郝丰富 杨聪发 万勇 《岩土力学》 北大核心 2026年第1期39-48,60,共11页
膨润土的主要黏土矿物为蒙脱石,其片层因同晶替代带有固定负电荷,形成的层电荷是控制其收缩行为的关键因素。通过试验与理论结合,探讨了层电荷对膨润土收缩特性的影响机制。试验中,以钠基膨润土为原料,利用锂离子固定法制备了一系列层... 膨润土的主要黏土矿物为蒙脱石,其片层因同晶替代带有固定负电荷,形成的层电荷是控制其收缩行为的关键因素。通过试验与理论结合,探讨了层电荷对膨润土收缩特性的影响机制。试验中,以钠基膨润土为原料,利用锂离子固定法制备了一系列层电荷逐渐降低的减电荷膨润土。采用数字图像法获得收缩特征曲线,并结合露点水势仪和核磁共振仪,获取土-水特征曲线及水分分布。结果表明,随着层电荷降低,膨润土由高收缩性逐渐转为低收缩性,收缩曲线出现结构收缩阶段,并可根据拐点划分为毛细作用阶段与吸附作用阶段,该拐点与水分分布特征高度一致。层电荷降低同时削弱了持水能力,但经阳离子交换量归一化后,土-水特征曲线在高吸力区段趋于重合,表明吸附阶段主要受层间可交换阳离子水化作用控制。采用粒间应力表征的脱湿诱导压缩曲线显示,收缩变形主要发生在毛细阶段,为弹塑性变形,而在吸附阶段则转为弹性变形。综合分析可知,收缩特征曲线、水分分布、土-水特征曲线和脱湿诱导压缩曲线在毛细与吸附阶段的分界点高度一致。 展开更多
关键词 层电荷 减电荷膨润土 收缩特征曲线 土-水特征曲线 粒间应力
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