检索结果-南通市图书馆

Identifying vital edges in Chinese air route network via memetic algorithm

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2017年第1期30卷 330-336页

作者： Du Wenbo Liang boyuan Yan Gang Oriol Lordan cao Xianbin School of Electronic and Information Engineering Beihang University Beijing 100191 China Beijing Key Laboratory for Network-based Cooperative Air Traffic Management Beijing 100191 China School of Physics Science and Engineering Tongji University Shanghai 200092 China Universitat Politecnica de Catalunya-BarcelonaTech C/Colom no. 11 Terrassa 08222 Spain

Due to rapid development in the past decade, air transportation system has attracted considerable research attention from diverse communities. While most of the previous studies focused on airline networks, here we systematically explore the robustness of the Chinese air route network, and identify the vital edges which form the backbone of Chinese air transportation ***, we employ a memetic algorithm to minimize the network robustness after removing certain edges, and hence the solution of this model is the set of vital edges. Counterintuitively,our results show that the most vital edges are not necessarily the edges of the highest topological importance, for which we provide an extensive explanation from the microscope view. Our findings also offer new insights to understanding and optimizing other real-world network systems.

关键词： Air route network Air transport network Memetic algorithm Robustness Vital edges

Metal-organic frameworks with mixed-ligands strategy as heterogeneous nucleation center to assist crystallization for efficient and stable perovskite solar cells

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2023年第2期77卷 1-10,I0001页

作者： Yayu Dong Shuang Gai Jian Zhang Ruiqing Fan boyuan Hu Wei Wang Wei cao Jiaqi Wang Ke Zhu Debin Xia Lin Geng Yulin Yang MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001HeilongjiangChina School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001HeilongjiangChina

Deep-level defects and random oriented configuration in perovskite crystallization process would cause the nonradiative recombination and further affect the performance of perovskite solar cells(PSCs).Herein,two metal-organic frameworks(MOFs)with tunable Lewis-base passivation sites have been constructed(Cd-Httb and Cd-Httb-BDC,Httb=5-(4-(1H-1,2,4-triazole-1-yl)benzyl)-1h-tetrazole,BDC=1,4-dicarboxybenzene)to eliminate deep-level defects and simultaneously as nanostructured heterogeneous nucleation seed to assist the growth of large-grained perovskite *** with the control and Cd-Httb,Cd-Httb-BDC designed with mix-ligands strategy exhibited the enhanced inducted effect on the crystallization and nucleation of high-quality perovskite films during annealing ***,the resultant Cd-Httb-BDC-modified device achieved higher power conversion efficiency(PCE)(22.18%)than the control(20.89%)and Cd-Httb(21.56%).Meanwhile,the unencapsulated Cd-Httb-BDC-modified device still maintained 90%of initial PCE after 1500 h in ambient conditions and exhibited enhanced thermal stability(85℃ in N_(2) atmosphere).This work presented a successful example of mixligands strategy on construction of high-quality MOF-assisted perovskite films for high-efficient and stable PSCs.

关键词： Perovskite solar cells Metal organic frameworks Mixed ligands strategy Passivation Stability

Manipulation and optimization of electron transport by nanopore array targets

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2021年第1期23卷 8-14页

作者： Yue YANG boyuan LI Yuchi WU Bin ZHU Bo ZHANG Zhimeng ZHANG Minghai YU Feng LU Kainan ZHOU Lianqiang SHAN Lihua cao Zongqing ZHAO Weimin ZHOU Yuqiu GU Laser Fusion Research Center China Academy of Engineering PhysicsMianyang 621900People’s Republic of China Key Laboratory for Laser Plasmas(Ministry of Education) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Institute of Applied Physics and Computational Mathematics Beijing 100088People’s Republic of China Key Laboratory of HEDP of the Ministry of Education&CAPT Peking UniversityBeijing 100871People’s Republic of China

The transport of sub-picosecond laser-driven fast electrons in nanopore array targets is *** to the generation of micro-structured magnetic fields,most fast electron beams are proven to be effectively guided and restricted during the *** transport patterns of fast electrons in the targets are observed in experiments and reproduced by particle-in-cell simulations,representing two components:initially collimated low-energy electrons in the center and high-energy scattering electrons turning into surrounding annular *** critical energy for confined electrons is deduced *** electron guidance and confinement by the nano-structured targets offer a technological approach to manipulate and optimize the fast electron transport by properly modulating pulse parameters and target design,showing great potential in many applications including ion acceleration,microfocus x-ray sources and inertial confinement fusion.

关键词： nanopore array laser-driven electrons fast electron transport electron collimation

Effect of arteriosclerotic intracranial arterial vessel wall enhancement on downstream collateral flow

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2023年第18期136卷 2221-2228页

作者： Liqun Yan Jin Yan Zhenchang Wang Guoshi Wang Zhenzhong Li Yaping Hou boyuan Huang Qianbo Dong Xiaodan Mu Wei cao Pengfei Zhao Department of Radiology Beijing Friendship Hospital of Capital Medical UniversityBeijing 100050China Departments of Medical Imaging Second Hospital of Hebei Medical UniversityShijiazhuangHebei 050004China Department of Clinical Medicine Tianjin Medical UniversityTianjin 300203China Departments of Neurology Second Hospital of Hebei Medical UniversityShijiazhuangHebei 050004China Hebei Province Blood Center ShijiazhuangHebei 050000China

Background:The effect of arteriosclerotic intracranial arterial vessel wall enhancement(IAVWE)on downstream collateral flow found in vessel wall imaging(VWI)is not *** of the mechanism underlying IAVWE on VWI,damage to the patient’s nervous system caused by IAVWE is likely achieved by affecting downstream cerebral blood *** present study aimed to investigate the effect of arteriosclerotic IAVWE on downstream collateral ***:The present study recruited 63 consecutive patients at the Second Hospital of Hebei Medical University from January 2021 to November 2021 with underlying atherosclerotic diseases and unilateral middle cerebral artery(MCA)M1-segment stenosis who underwent an magnetic resonance scan within 3 days of symptom *** patients were divided into 4 groups according to IAVWE and the stenosis ratio(Group 1,n=17;Group 2,n=19;Group 3,n=13;Group 4,n=14),and downstream collateral flow was analyzed using three-dimensional pseudocontinuous arterial spin labeling(3D-pCASL)and RAPID *** National Institutes of Health Stroke Scale(NIHSS)scores of the patients were also ***-factor multivariate analysis of variance using Pillai’s trace was used as the main statistical ***:No statistically significant difference was found in baseline demographic characteristics among the ***,but not the stenosis ratio,had a statistically significant significance on the late-arriving retrograde flow proportion(LARFP),hypoperfusion intensity ratio(HIR),and NIHSS scores(F=20.941,P<0.001,Pillai’s trace statistic=0.567).The between-subject effects test showed that IAVWE had a significant effect on the three dependent variables:LARFP(R^(2)=0.088,F=10.899,P=0.002),HIR(R^(2)=0.234,F=29.354,P<0.001),and NIHSS(R^(2)=114.339,F=33.338,P<0.001).Conclusions:Arteriosclerotic IAVWE significantly reduced downstream collateral flow and affected relevant neurological *** was an independent factor affecting downstream collateral fl

关键词： Intracranial arterial vessel wall enhancement Arteriosclerosis Stroke Cerebral collateral flow Three-dimensional pseudo-continuous arterial spin-labeling Magnetic Resonance Imaging

Determination of Nitrogen in Steel Using Optical Emission Spectrometry

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 1999年第1期6卷 48-52页

作者： cao Cheng Li Shimin Jia Yunhai Yuan Pengfei Central Iron & Steel Research Institute

The rapid quantitative analysis of nitrogen in steel with optical emission spectrometry is *** problems about the selection of spectral line for the determination of nitrogen,the analytical conditions of nitrogen,the preparation of analytical sample,the effect of co-existing element and the calibration curve of nitrogen are *** analytical range of nitrogen is 0.000 5%to 0.30%,the limit of detection is 0.000 374%,the analytical time is less than 2 min(including the preparation of sample and the exciting sample for two times).Nitrogen in steel is simultaneously determined with alloy elements and acid soluble/insoluble compounds of aluminium.

关键词： nitrogen steel optical emission spectrometry

同方期刊数据库

超高效液相色谱-串联质谱法测定尿液中血栓素A_(2)的3种代谢物和8-异前列腺素F_(2α)

在线全文

学校读者我要写书评

暂无评论

色谱 2025年第2期43卷 148-154页

作者：刘思佳赵福荣张亚莲孙晓宇张萌萌侯琨曹云峰锦州医科大学药学院辽宁锦州121001 上海市生物医药技术研究院上海市疾病与健康基因组学重点实验室国家卫生健康委员会计划生育药具重点实验室上海200237 锦州医科大学辽宁省肿瘤临床代谢组学重点实验室辽宁锦州121001 大连博源医学科技有限公司辽宁大连116011

建立了同时测定人体尿液中血栓素A_(2)的3种代谢物(2,3-地诺血栓素B_(2)、11-脱氢-2,3-地诺血栓素B_(2)和11-脱氢血栓素B_(2))和8-异前列腺素F_(2α)的超高效液相色谱-串联质谱检测方法。尿液经盐酸酸化至pH 2.0~4.0,经C18固相萃取柱净... 详细信息

建立了同时测定人体尿液中血栓素A_(2)的3种代谢物(2,3-地诺血栓素B_(2)、11-脱氢-2,3-地诺血栓素B_(2)和11-脱氢血栓素B_(2))和8-异前列腺素F_(2α)的超高效液相色谱-串联质谱检测方法。尿液经盐酸酸化至pH 2.0~4.0,经C18固相萃取柱净化后测定。使用ACQUITY UPLC^(■) BEH Phenyl色谱柱(50 mm×2.1 mm,1.7μm),以含0.002%氨水的2 mmol/L乙酸铵水溶液和乙腈作为流动相进行梯度洗脱,流速为0.3 mL/min,柱温为40℃,采用电喷雾离子源,在负离子和多反应监测模式下分析4 min,内标法定量。4种目标化合物在各自范围内线性关系良好,相关系数(R^(2))大于0.99;方法检出限为2,3-地诺血栓素B_(2)0.02 ng/mL,其余目标化合物0.01 ng/mL;定量限为2,3-地诺血栓素B_(2)0.1 ng/mL,其余目标化合物0.05 ng/mL;实际尿液中,4种目标物在定量限水平下的加标回收率为91.48%~104.87%,低、中、高水平下的加标回收率为92.95%~104.90%,日内精密度为2.79%~13.01%,日间精密度为4.45%~13.67%。应用该方法测定健康人群和缺血性脑卒中患者血栓素A_(2)的3种代谢物和8-异前列腺素F_(2α)的含量,并用肌酐进行校正。对目标化合物进行二元Logistic回归分析并绘制受试者工作特征曲线(ROC曲线)用于诊断,血栓素A_(2)(血栓素A_(2)的3种代谢物加和)的曲线下面积(AUC)为0.849,8-异前列腺素F_(2α)的AUC为0.775,具有较好的临床价值,有望辅助缺血性脑卒中的早期筛查诊断。

关键词：超高效液相色谱-串联质谱 2,3-地诺血栓素B_(2) 11-脱氢-2,3-地诺血栓素B_(2) 11-脱氢血栓素B_(2) 8-异前列腺素F_(2α) 尿液缺血性脑卒中

New Heat Treatment Technology for Grain Refining of Structural Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2005年第6期12卷 49-53页

作者： Lü Bo ZHANG Fu-cheng cao Guo-hua ZHANG Ji-ming Yanshan University Qinhuangdao 066004 China Key Laboratory of Metastable MaterialsScience and Technology Qinhuangdao 066004 China）

The application of electrical contact heating （ECH） in austenitic grain refining of ultra-pure 42CrMoVNb steel was introduced. The ECH equipment was designed to reach uniform heating of uniform heat transfer in the sample. The 42CrMoVNb steel treated possesses uniform microstructure with an average austenite grain size of 1.4 μm, higher strength （1 538 MPa） and impact toughness （81J/cm^2）.

关键词： electrical contact heating medium carbon alloy steel ultrafine grain 42CrMoVNb

基于深度学习的超低碳钢显微组织特征强化与精细化分析

在线全文

学校读者我要写书评

暂无评论

钢铁 2025年第02期60卷 119-127页

作者：王煜乔吴思炜曹光明刘建军窦君闫新悦刘振宇东北大学轧制技术与连轧自动化国家重点实验室

超低碳钢显微组织为铁素体，在制样过程中极易出现划痕和晶界腐蚀不清晰的现象，严重影响金相组织分析。同时，显微组织特征的分析结果严重依赖于专家经验，受主观因素影响较大且效率低。为了高效获得超低碳钢显微组织特征信息，基于超... 详细信息

超低碳钢显微组织为铁素体，在制样过程中极易出现划痕和晶界腐蚀不清晰的现象，严重影响金相组织分析。同时，显微组织特征的分析结果严重依赖于专家经验，受主观因素影响较大且效率低。为了高效获得超低碳钢显微组织特征信息，基于超低碳钢金相图像数据集，采用归一化、自适应阈值法处理图像，增强图像对比度；融合自注意力机制（Self-Attention,SA）和循环回归生成对抗神经网络（CycleGan），开发基于CycleGan+SA的晶界增强算法；建立超低碳钢显微组织特征强化模型，实现了显微组织图像的自动处理与晶界信息的特征强化。在此基础上，采用分水岭分割算法对晶界强化后的显微组织图像进行精细化分析。结果表明，CycleGan+SA算法可以有效去除原始金相图像中的划痕并补全晶界模糊区域，实现超低碳钢晶界特征强化。相比原始的CycleGan算法，引入注意力机制后，CycleGan+SA算法可以实现更清晰的晶粒分割，图像识别精确度P值由97.43%提升至98.75%，综合评价指标F值由97.49%提升至98.73%。在显微组织精细化分析方面，通过与常用分析软件对比，超低碳钢显微组织特征强化模型与Image J软件测定的晶粒尺寸平均误差为1.2个晶粒，与Image Pro Plus软件测定的晶界比例误差为0.008个百分点，模型与软件统计结果吻合较好，具备一定的应用前景。

关键词： CycleGan 自注意力机制深度学习晶界特征强化超低碳钢图像识别分水岭分割算法超低碳钢

同方期刊数据库

1100kV气体绝缘开关设备用盆式绝缘子中心嵌件结构设计

在线全文

学校读者我要写书评

暂无评论

高电压技术 2016年第2期42卷 564-570页

作者：陈允崔博源王宁华吴昱怡曹德新程鹏中国电力科学研究院北京100192 国家电网公司北京100031

为改善1 100 k V GIS用盆式绝缘子的机械性能,在现有盆式绝缘子中心嵌件结构(结构A)的基础上,重新设计了B、C 2种结构,对其进行了界面力学仿真和水压试验;并仿真计算、分析了其绝缘性能。结果表明,B、C 2种结构均能显著提高盆式绝缘子... 详细信息

为改善1 100 k V GIS用盆式绝缘子的机械性能,在现有盆式绝缘子中心嵌件结构(结构A)的基础上,重新设计了B、C 2种结构,对其进行了界面力学仿真和水压试验;并仿真计算、分析了其绝缘性能。结果表明,B、C 2种结构均能显著提高盆式绝缘子水压破坏强度值、减小分散性。但结构C的绝缘裕度较低,个别三交区位置的电场强度已经超出了许用值。因此,综合考虑机械和电气性能,宜优先采用结构B的盆式绝缘子。

关键词：特高压盆式绝缘子中心嵌件结构设计水压破坏强度机械性能绝缘性能