检索结果-南通市图书馆

热等静压制备TC4合金内筋圆筒件的组织与力学性能

在线全文

学校读者我要写书评

暂无评论

中国有色金属学报 2024年第7期34卷 2257-2272页

作者：徐博董添添邓太庆易卓勋徐岩贾建波燕山大学先进锻压成形技术与科学教育部重点实验室秦皇岛066004 燕山大学先进制造成形技术及装备国家地方联合工程研究中心秦皇岛066004 航天材料及工艺研究所北京100076 中国空间技术研究院北京卫星制造厂有限公司北京100094

采用有限元模拟技术研究TC4合金内筋筒形件在热等静压(HIP)过程中的致密化行为,通过响应面技术获得优化的HIP工艺参数,并开展优化工艺条件下的HIP实验;分别对HIP制备TC4合金内筋筒形件的不同部位开展致密度、力学性能测试以及微观组织... 详细信息

采用有限元模拟技术研究TC4合金内筋筒形件在热等静压(HIP)过程中的致密化行为,通过响应面技术获得优化的HIP工艺参数,并开展优化工艺条件下的HIP实验;分别对HIP制备TC4合金内筋筒形件的不同部位开展致密度、力学性能测试以及微观组织和断口形貌表征。结果表明:TC4合金内筋筒形件的外表面优先致密,筒壁和筒底芯部的致密度最高,HIP压力对致密化的影响高于保温保压时间对致密化的影响;HIP制件筒壁和筒底的组织致密均匀、室温拉伸性能接近,筒壁室温拉伸性能均略优。350℃时,筒壁和筒底的拉伸性能差值进一步缩小,抗拉强度保持率达到近70%。室温和350℃拉伸变形试样均以韧性断裂为主的断裂特征。

关键词： TC4合金内筋筒形件热等静压致密化微观组织力学性能

在线全文

学校读者我要写书评

暂无评论

华北土石山区油松生长季夜间液流分配特征

林业科学 2024年第4期60卷 91-98页

作者：胡蕾贾剑波闫文德王一帆吴瑞乔陈玉中南林业科技大学长沙410004 湖南芦头森林生态系统国家定位观测研究站岳阳414000 南方林业生态应用技术国家工程实验室长沙410004

【目的】通过对油松生长季夜间液流特征和环境驱动因素的研究,揭示夜间液流组分拆分特征,探讨夜间液流的组分与气象因子之间的相关关系,以及茎干补水对气象因子的响应,为华北土石山区水资源和水源涵养林管理决策提供理论依据。【方法】... 详细信息

【目的】通过对油松生长季夜间液流特征和环境驱动因素的研究,揭示夜间液流组分拆分特征,探讨夜间液流的组分与气象因子之间的相关关系,以及茎干补水对气象因子的响应,为华北土石山区水资源和水源涵养林管理决策提供理论依据。【方法】以华北土石山区的油松作为研究对象,根据径阶大小选取18棵样树,在2014年生长季运用Granier热扩散探针技术(TDP)持续观测夜间液流,结合称重式蒸渗仪和自制微型蒸渗仪来计算蒸腾量,解析夜间液流的去向;并进行夜间液流与土壤含水量、大气温度、湿度及光合有效辐射等气象因子的相关分析,以确定主要驱动因素。【结果】在6—9月典型晴天,夜间液流速率都呈逐渐降低趋势,18:00—24:00的夜间液流速率高于00:00—05:00,夜间液流主要用于对白天失水过多的茎干进行补水,以至于在24:00时油松茎干储水量基本达到饱和,因此,00:00—05:00夜间液流速率趋于稳定;油松夜间液流用于茎干补水的比例(95.34%)显著高于用于夜间蒸腾量的比例(4.66%);油松夜间茎干补水量与饱和水汽压差呈极显著正相关(R^(2)=0.793,P0.05),表明夜间液流主要受饱和水汽压影响。【结论】华北土石山区的油松生长季夜间液流随着夜间时间的进行呈现逐渐降低的趋势;绝大部分的夜间液流用于夜间茎干补水,在气象因子中,饱和水汽压是驱动夜间茎干补水及夜间液流的重要因子(P<0.01)。

关键词：夜间液流分配特征茎干补水夜间蒸腾华北土石山区

Response of forestland soil water content to heavy rainfall on Beijing Mountain, northern China

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2016年第3期27卷 541-550页

作者： jianbo jia Xinxiao Yu Yitao Li College of Soil and Water Conservation Beijing Forestry University Beijing 100083 People's Republic of China Shanxi Institute of Forest Inventory and Planning Taiyuan 030012 People's Republic of China

Continuous recording of precipitation and soil water content（SWC）, especially during long periods of torrential rainfall, has proven challenging. Over a 16 h period spanning 21-22 July, 2012, Beijing experienced historic rainfall that totaled 164.4 mm. We used large lysimeter technology in four forested plots to record precipitation and variation in SWC at 10-min intervals to quantify the response of forestland SWC to heavy rainfall in a semi-arid area. Mean,maximum and minimum rainfall intensities were 23.4, 46.8and 12.0 mm/h, respectively. Rainfall was concentrated in 2-6 mm bursts that accounted for 67.32 % of the total rainfall event. Soil moisture conditions in this region are strongly dependent on patterns of precipitation. Water infiltration into 20, 40, 60, 80, 100, 120 and 160 cm soil layers required 1, 5,20, 37, 46, 52 and 61 mm of precipitation, respectively, and to fully saturate these soil layers required 80, 120, 140, 150, 180,200 and 220 mm of precipitation, respectively.

关键词： Semi-arid region Soil water content Soilwater deficit Lysimeter

Recent advances in carbon-based electrocatalysts for oxygen reduction reaction

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2020年第3期31卷 626-634页

作者： Lulu Chen Xiaolong Xu Wenxiu Yang jianbo jia State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Science and Technology of China Hefei 230026China Department of Materials Science&Engineering&Department of Energy and Resources Engineering College of EngineeringPeking UniversityBeijing 100871China School of Chemical and Environmental Engineering Wuyi UniversityJiangmen 529020China

Fuel cells are one of the most promising clean energy devices to substitute for fossil fuel in the future to alleviate energy crisis and environmental *** the key reaction on the cathode in the fuel cells,oxygen reduction reaction(ORR)still requires efficient noble metal catalysts such as the comme rcial Pt/C to boost the reaction for its sluggish ***,it is critical to design earth-abundant carbonbased catalysts with high efficiency and long-term stability to replace the noble metal-based *** review focuses on the recent progress about carbon-based ORR catalysts including non-metal doped carbon materials,transition metal-nitrogen-carbon species,transition metal carbides/carbon,single atom catalysts,and other carbon *** we further infer that the excellent ORR performances can be achieved by the balance of geometric and electronic structures of catalysts such as conductivity,surface area,hierarchical porous structure,defect and doping ***,the perspective development trend is also proposed to guide the rational designation of carbon-based catalysts for ORR and even extend to other energy storage and conversion fields in the future.

关键词： Oxygen reduction reaction Carbon materials Transition metal catalysts Single atom catalysts Fuel cells

在线全文

学校读者我要写书评

暂无评论

弹簧式安全阀启闭动态过程仿真与分析

哈尔滨理工大学学报 2024年第1期29卷 25-34页

作者：闫旭徐娇李忠刚于广滨贾建波长春理工大学机电工程学院长春130012 哈电集团哈尔滨电站阀门有限公司哈尔滨150046 哈尔滨工业大学机电工程学院哈尔滨150001

为研究安全阀的启闭性能,采用数学建模方法对其性能进行仿真分析。首先,根据安全阀工作原理将其内部主要活动部件分别建立成等效模型,然后采用数值模拟方法对部件刚度进行求解,再通过流体分析及数据拟合来获得阀瓣推力,建立数学公式并... 详细信息

为研究安全阀的启闭性能,采用数学建模方法对其性能进行仿真分析。首先,根据安全阀工作原理将其内部主要活动部件分别建立成等效模型,然后采用数值模拟方法对部件刚度进行求解,再通过流体分析及数据拟合来获得阀瓣推力,建立数学公式并采用龙格库塔法进行方程求解,以获得启闭过程的运动曲线。结果表明,根据数学模型求解出的运动曲线趋势与安全阀实际运动趋势相同。由此可知,数学建模结果为安全阀性能分析提供理论依据。

关键词：安全阀启闭特性数学模型流体分析运动仿真

Zn^(2+) loading as a critical contributor to the circ_0008553-mediated oxidative stress and inflammation in response to PM_(2.5) exposures

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2023年第2期124卷 451-461页

作者： Jingzhou Wang jianbo jia Dujia Wang Xiujiao Pan Haiyan Xiong Chengjun Li Yiguo jiang Bing Yan Institute of Environmental Research at Greater Bay Area Key Laboratory for Water Quality and Conservation of the Pearl River DeltaMinistry of EducationGuangzhou UniversityGuangzhou 510006China School of Environmental Science and Engineering Shandong UniversityQingdao 266237China Institute for Chemical Carcinogenesis Guangzhou Medical UniversityGuangzhou 511436China

Inflammation is a major adverse outcome induced by inhaled particulate matter with a diameter of≤2.5μm(PM_(2.5)),and a critical trigger ofmost PM_(2.5) exposure-associated ***,the key molecular events regulating the PM_(2.5)-induced airway inflammation are yet to be *** the critical role of circular RNAs(circRNAs)in regulating inflammation,we predicted 11 circRNAs that may be involved in the PM_(2.5)-induced airway inflammation using three previously reportedmiRNAs through the starBasewebsite.A novel circRNA circ_0008553 was identified to be responsible for the PM_(2.5)-activated inflammatory response in human bronchial epithelial cells(16HBE)via inducing oxidative *** a combinatorial model PM_(2.5) library,we found that the synergistic effect of the insoluble core and loaded Zn^(2+)ions at environmentally relevant concentrations was the major contributor to the upregulation of circ_0008553 and subsequent induction of oxidative stress and inflammation in response to PM2.5 *** findings provided new insight into the intervention of PM_(2.5)-induced adverse outcomes.

关键词： PM(2.5) Toxic composition Combinatorial model PM_(2.5)library Circ_0008553 Inflammation

在线全文

学校读者我要写书评

暂无评论

B掺杂多孔碳纳米片的制备及其储锂性能

化工进展 2024年第6期43卷 3209-3220页

作者：孙悦邢宝林张耀杰冯来宏曾会会蒋振东徐冰贾建波张传祥谌伦建张越张文豪河南理工大学化学化工学院河南焦作454000 煤炭安全生产与清洁高效利用省部共建协同创新中心河南焦作454000 华能煤炭技术研究有限公司北京100071

负极材料是影响锂离子电池(LIBs)性能的关键因素之一,孔隙结构调控和杂原子掺杂是提高负极材料电化学性能的有效手段。以褐煤为前体,采用化学氧化法制备煤基碳纳米片(CS),再以氧化硼(B_(2)O_(3))为添加剂,得到B掺杂多孔碳纳米片(BPCS);... 详细信息

负极材料是影响锂离子电池(LIBs)性能的关键因素之一,孔隙结构调控和杂原子掺杂是提高负极材料电化学性能的有效手段。以褐煤为前体,采用化学氧化法制备煤基碳纳米片(CS),再以氧化硼(B_(2)O_(3))为添加剂,得到B掺杂多孔碳纳米片(BPCS);采用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)、拉曼光谱(Raman)、氮气吸附仪、X射线光电子能谱(XPS)等手段对CS和BPCS微观结构和用作锂离子电池负极材料的电化学性能表征与测试。结果表明,B_(2)O_(3)具有模板、造孔、掺杂三重作用,当B_(2)O_(3)用量为0.5g时,BPCS-0.5呈现三维多孔结构,比表面积为1216.20m^(2)/g,总孔容1.027cm^(3)/g,B原子含量为4.20%;BPCS-0.5的多孔结构为离子的存储和传输提供足够的空间和通道,B元素的引入增加了BPCS的表面化学活性,从而增强了储锂性能。BPCS-0.5用作锂离子电池负极材料时,在0.05A/g电流密度下首次可逆容量达826mA·h/g,且在5A/g大电流密度下可逆容量仍有143mA·h/g,循环500次的容量保持率为172%,表明该材料具有较高的储锂容量和优异的循环寿命。

关键词：褐煤 B掺杂多孔碳纳米片锂离子电池电化学性能

Recent advances in electrochemical sensors for antibiotics and their applications

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2021年第2期32卷 609-619页

作者： Qun Wang Qiang Xue Tao Chen jiawei Li Yuehua Liu Xiaohan Shan Fei Liu jianbo jia M0E Key Laboratory of Groundwater Circulation and Environmental Evolution China University of Geosciences(Beijing)Beijing 100083China Beijing Key Laboratory of Water Resources and Environmental Engineering China University of Geosciences(Beijing)Beijing 100083China School of Biotechnology and Health Sciences Wuyi UniversityJiangmen 529020China

The abuse of antibiotics will cause an increase of drug-resistant strains and environmental pollution,which in turn will affect human ***,it is important to develop effective detection techniques to determine the level of antibiotics contamination in various *** with traditional detection methods,electrochemical sensors have received extensive attention due to their advantages such as high sensitivity,low detection limit,and good *** this mini review,we summarized the latest developments and new trends in electrochemical sensors for ***,modification methods and materials of electrode are *** also pay more attention to the practical applications of antibiotics electrochemical sensors in different *** addition,the existing problems and the future challenges ahead have been *** hope that this review can provide new ideas for the development of electrochemical sensors for antibiotics in the future.

关键词： Antibiotics Electrochemical sensor Electrodes Modified materials Applications

在线全文

学校读者我要写书评

暂无评论

碳薄膜电极材料在电分析化学中的应用

化学进展 2007年第11期19卷 1800-1805页

作者：郏建波中国科学院长春应用化学研究所电分析化学国家重点实验室长春130022

由于具有一系列的优点,碳材料被广泛应用于电分析化学。新型碳电极材料的开发及其性质研究对电分析化学的发展起着重要的推动作用。最近报道了一些制备新型碳薄膜电极材料的方法,因为制备方法不同,这些碳薄膜材料的电化学性质如电位窗... 详细信息

由于具有一系列的优点,碳材料被广泛应用于电分析化学。新型碳电极材料的开发及其性质研究对电分析化学的发展起着重要的推动作用。最近报道了一些制备新型碳薄膜电极材料的方法,因为制备方法不同,这些碳薄膜材料的电化学性质如电位窗、稳定性、导电性也存在显著的差异。目前电位窗宽、背景电流低、稳定性高、表面不易被电极产物钝化的碳薄膜电极材料的研究非常活跃。本文综述了采用不同方法制备的一些碳薄膜电极材料如硼掺杂的金刚石薄膜、无定形碳和纳米晶体碳薄膜材料等在电分析化学中应用。

关键词：碳薄膜硼掺杂的金刚石薄膜电子回旋加速共振碳薄膜电位窗稳定性