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Reanalysis of energy band structure in the type-II quantum wells

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Chinese Physics B 2024年第6期33卷 75-78页

作者：李欣欣邓震江洋杜春花贾海强王文新陈弘 Key Laboratory for Renewable Energy Beijing Key Laboratory for New Energy Materials and DevicesBeijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing 100190China Center of Materials and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China The Yangtze River Delta Physics Research Center Liyang 213000China Songshan Lake Materials Laboratory Dongguan 523808China

Band structure analysis holds significant importance for understanding the optoelectronic characteristics of semiconductor structures and exploring their potential applications in practice. For quantum well structures, the energy of carriers in the well splits into discrete energy levels due to the confinement of barriers in the growth direction. However, the discrete energy levels obtained at a fixed wave vector cannot accurately reflect the actual energy band structure. In this work, the band structure of the type-II quantum wells is reanalyzed. When the wave vectors of the entire Brillouin region(corresponding to the growth direction) are taken into account, the quantized energy levels of the carriers in the well are replaced by subbands with certain energy distributions. This new understanding of the energy bands of low-dimensional structures not only helps us to have a deeper cognition of the structure, but also may overturn many viewpoints in traditional band theories and serve as supplementary to the band theory of low-dimensional systems.

关键词： energy band structure type-II quantum wells low-dimensional semiconductors

血清皮质醇、胰岛素生长因子结合蛋白-3、25-羟维生素D在特发性矮小症患儿中的表达及意义

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中国儿童保健杂志 2024年第6期32卷 678-681+686页

作者：贺莉吕加利李俊杜春华成都市龙泉驿区妇幼保健院儿童保健科

目的探讨血清皮质醇、胰岛素生长因子结合蛋白-3(IGFBP-3)、25-羟维生素D[25-(OH)D]在特发性矮小症(ISS)患儿中的表达及意义。方法选取2020年4月—2022年6月于成都市龙泉驿区妇幼保健院诊治的86例ISS患儿作为观察组，同期选取43例健... 详细信息

目的探讨血清皮质醇、胰岛素生长因子结合蛋白-3(IGFBP-3)、25-羟维生素D[25-(OH)D]在特发性矮小症(ISS)患儿中的表达及意义。方法选取2020年4月—2022年6月于成都市龙泉驿区妇幼保健院诊治的86例ISS患儿作为观察组，同期选取43例健康体检儿童为对照组，对比基线资料、血清皮质醇、IGFBP-3、25-(OH)D水平；采用Pearson法分析皮质醇、IGFBP-3、25-(OH)D与身高、体重、体质量指数(BMI)的相关性；采用Logistic回归模型构建皮质醇、IGFBP-3、25-(OH)D联合诊断ISS模型；采用ROC曲线模型分析皮质醇、IGFBP-3、25-(OH)D及三项联合诊断ISS的AUC值、敏感度、特异度。结果观察组身高、体重、BMI均低于对照组(t=6.472、15.193、5.208,P<0.05)。观察组皮质醇水平高于对照组，而IGFBP-3、25-(OH)D水平低于对照组(t=4.505、5.341、4.857,P<0.05)。Pearson相关性分析显示，血清皮质醇水平与身高、体重、BMI呈负相关(r=-0.231、-0.716、-0.720,P<0.05);血清IGFBP-3、25-(OH)D水平分别与身高、体重、BMI呈正相关(r=0.200、0.612、0.636、0.365、0.716、0.715,P<0.05)。ROC曲线分析显示，皮质醇、IGFBP-3、25-(OH)D及三项联合诊断ISS的AUC值分别为0.750、0.736、0.728、0.941(P<0.05),敏感度分别为54.70%、93.00%、90.70%、93.00%;特异度分别为88.40%、53.50%、51.20%、79.10%。结论血清皮质醇、IGFBP-3、25-(OH)D在ISS患儿中呈异常表达，监测其水平变化有利于及早发现ISS提供指导。

关键词：皮质醇胰岛素生长因子结合蛋白-3 25-羟维生素D 特发性矮小症

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连续光纤激光切割金属薄壁材料工艺研究

红外与激光工程 2024年第2期53卷 25-35页

作者：翟兆阳李欣欣张延超刘忠明杜春华张华明西安理工大学机械与精密仪器工程学院陕西西安710048 郑州机械研究所有限公司河南郑州450052 广东工业大学省部共建精密电子制造技术与装备国家重点实验室广东广州510006

随着工业领域金属薄壁构件设计的多样化,在高速激光切割的同时,对切口形貌质量也提出了更高的要求。本研究采用连续光纤激光器对0.2 mm厚度304不锈钢薄板进行切割实验,研究了毛刺和熔渣飞溅区产生的机理,重点讨论了加工工艺参数中的激... 详细信息

随着工业领域金属薄壁构件设计的多样化,在高速激光切割的同时,对切口形貌质量也提出了更高的要求。本研究采用连续光纤激光器对0.2 mm厚度304不锈钢薄板进行切割实验,研究了毛刺和熔渣飞溅区产生的机理,重点讨论了加工工艺参数中的激光功率、切割速度、离焦量对毛刺堆积量和熔渣飞溅区宽度的影响关系,通过实验分析获得了最佳加工参数组合。研究结果表明,毛刺厚度随着激光功率、离焦量的增大而增加,随着切割速度的增大先降低后增加。熔渣飞溅区宽度随着激光功率的增大而增加,随着切割速度的增大而降低,随着离焦量的增大出现小范围波动。根据加工结果分析,当激光功率为125 W,切割速度为10 m/min,辅助气体压强为1.2 MPa,离焦量为-0.3~-0.5 mm,可以获得0.2 mm厚304不锈钢薄板较好的加工效果。

关键词：激光切割薄壁 304不锈钢毛刺熔渣飞溅区

圆弧型指尖密封径向极限变形量的计算方法研究

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推进技术 2024年第7期45卷 219-226页

作者：杜春华王源张延超宋丹龙吉洪湖西安理工大学机械与精密仪器工程学院陕西西安710048 台州市大江实业有限公司浙江台州317500 南京航空航天大学能源与动力学院江苏南京210016

指尖密封是一种允许产生径向变形的接触式密封技术,径向极限变形制约着其使用工况要求。为揭示圆弧型指尖密封结构对径向极限变形的影响规律,构建了指尖密封径向极限变形量的数学计算模型,并与有限元分析结果进行了对比,研究了结构参数... 详细信息

指尖密封是一种允许产生径向变形的接触式密封技术,径向极限变形制约着其使用工况要求。为揭示圆弧型指尖密封结构对径向极限变形的影响规律,构建了指尖密封径向极限变形量的数学计算模型,并与有限元分析结果进行了对比,研究了结构参数的影响。研究表明:数学计算模型计算结果与有限元分析结果误差为4.88%;指尖密封径向极限变形量随指梁间隙、指梁根圆直径、指梁型线圆弧半径等结构参数的增加而增加;随周向角、指梁顶圆直径、指梁基圆半径等结构参数的增加而减小;结构参数影响程度由大到小依次为:指梁间隙、周向角、指梁根圆和指梁顶圆、指梁基圆、指梁型线圆;其中,指梁根圆和指梁顶圆的影响需要根据具体结构尺寸来确定;指梁间隙影响程度最大,指梁间隙每增加1 mm,小尺寸指尖密封径向极限变形量就会增加10.005 mm,大尺寸的就会增加9.03 mm。

关键词：指尖密封径向变形径向极限变形量结构参数数学计算模型

基于正交试验的金属薄壁材料激光切割工艺优化

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中国机械工程 2024年第7期35卷 1279-1289页

作者：翟兆阳李欣欣张延超刘忠明杜春华张华明西安理工大学机械与精密仪器工程学院西安713700 郑州机械研究所有限公司郑州450052 广东工业大学省部共建精密电子制造技术与装备国家重点实验室广州510006

激光切割后,金属薄壁类零件的材料基体与下方的支撑板易产生粘连,严重影响切割质量。采用光纤激光对304不锈钢和GH605高温合金薄板进行切割实验,分析了激光切割不同材料发生粘连的机理。采用单因素试验法分析了激光切割工艺参数对热影... 详细信息

激光切割后,金属薄壁类零件的材料基体与下方的支撑板易产生粘连,严重影响切割质量。采用光纤激光对304不锈钢和GH605高温合金薄板进行切割实验,分析了激光切割不同材料发生粘连的机理。采用单因素试验法分析了激光切割工艺参数对热影响区及毛刺堆积量的影响规律。加工结果显示,在加入微连工艺的前提下,激光功率为165 W,切割速度为5 m/min,辅助气体压力为1.2 MPa时,切缝边缘光滑、无变形及残留黏附现象。

关键词：激光切割薄壁粘附热影响区毛刺

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Perforated nitrogen-rich graphene-like carbon nanolayers supported Cu-In catalyst for boosting CO_(2) electroreduction to CO

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Journal of Energy Chemistry 2022年第12期75卷 383-390,I0010页

作者： Xinxin Zhang Yuxiao Zhu Ziyong Liu Fuli Li Wei Zhou Zichao Dong Jingxin Fan Licheng Liu chunhua du Laboratory of Reaction and Separation Technology Qingdao Agricultural UniversityQingdao 266109ShandongChina CAS Key Laboratory of Bio-based Materials Qingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdao 266101ShandongChina CenterTech Tianjin Chemical Research and Design Institute Co. Ltd.Tianjin 300131China

The combination of a powerful CO_(2)-enriching carrier and robust active component provides a new idea for the construction of efficient catalysts for electrocatalytic CO_(2)***,novel perforated nitrogen-rich graphene-like carbon nanolayers(PNGC)are prepared from biomass derivatives,which promotes the oriented deposition of In-doped Cu_(2)(OH)_(3)(NO_(3))nanosheet patches.A robust Cu-In/PNGC composite catalyst is then obtained via simple in-situ electrochemical ***,CuIn/PNGC exhibits a CO Faradaic efficiency(FECO)of 91.3%and a remarkable CO partial current density(jCO)of 136.4 m A cm^(-2)at a moderate overpotential of 0.59 V for electrocatalytic CO_(2)reduction reaction(CO_(2)RR).DFT calculations and experimental studies indicate that the strong carrier effect of PNGC makes PNGC carried Cu-In nanosheets improved the adsorption capacity of CO_(2)gas,reconfigured electronic structure,and reduced free energy of key intermediate formation,thereby the CO_(2)activation and conversion are promoted.

关键词： CO_(2)electroreduction CO Cu-In/PNGC Patch Perforated nitrogen-rich graphene-like carbon nanolayers

不同枝采时间对竹叶花椒结果枝生长量、产量和品质的影响

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西部林业科学 2024年第2期53卷 81-86页

作者：呼延丽郝佳波杜春花郭永清铁筱睿陆斌云南省林业和草原科学院云南昆明650201 云南省森林植物培育与开发利用重点实验室/国家林业和草原局云南珍稀濒特森林植物保护和繁育重点实验室云南昆明650201 昆明市海口林场云南昆明650114

为探明竹叶花椒枝采最佳时间,开展不同带枝采收时间(6月、7月、8月)对竹叶花椒结果枝生长量、产量和品质影响的研究。结果显示:(1)不同带枝采收时间,鲜果感官等级评价,7月>8月>6月;椒果干鲜比6.8︰1、5.2︰1、4.5︰1。(2)不同带枝采收时... 详细信息

为探明竹叶花椒枝采最佳时间,开展不同带枝采收时间(6月、7月、8月)对竹叶花椒结果枝生长量、产量和品质影响的研究。结果显示:(1)不同带枝采收时间,鲜果感官等级评价,7月>8月>6月;椒果干鲜比6.8︰1、5.2︰1、4.5︰1。(2)不同带枝采收时间,年末树冠投影面积新梢(结果枝)数量、鲜果产量、冠幅方差分析结果显示,6月、7月差异不显著(P>0.05),8月差异显著(P0.05),8月的长果枝产量差异达极显著(P0.05),8月的短果枝差异显著(P<0.05)。结果表明:6月中旬至7月中旬是竹叶花椒带枝采收最佳时间,采收后当年花椒商品性质量能得到保证,萌生的新梢生长量能够保证次年结果量。研究结果为竹叶花椒枝采轻简化栽培提供理论依据。

关键词：竹叶花椒带枝采收时间生长量产量品质

Insight into pyrolysis of hydrophobic silica aerogels:Kinetics,reaction mechanism and effect on the aerogels

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Chinese Journal of Chemical Engineering 2023年第6期58卷 266-281页

作者： Xinyu Liu Hongliang Sheng Song He chunhua du Yuansheng Ma Chichi Ruan Chunxiang He Huaming Dai Yajun Huang Yuelei Pan School of Safety Science and Emergency Management Wuhan University of TechnologyWuhan 430070China Wuhan Building Material Industry Design&Research Institute Co. LtdWuhan 430200China State Key Laboratory of Fire Science University of Science and Technology of ChinaHefei 230027China

Silica aerogels have promising applications in thermal insulation,but their flammability and reaction mechanisms have rarely been *** pyrolysis kinetics and thermodynamics of hydrophobic silica aerogels under N_(2) environment were *** kinetic and thermodynamic parameters were obtained by three model-free *** on the calculated kinetic parameters,the pyrolysis mechanism of silica aerogels was discussed by the master plots *** results indicate that the reactions of the whole pyrolysis phase can be characterized by a random nuclear *** addition,FTIR test results show that the volatile products of silica aerogel pyrolysis are mainly hydrocarbons generated by the decomposition of hydrophobic groups(methyl groups)on the ***,the effects of pyrolysis on the properties of silica aerogels Finally,the effects of pyrolysis on the properties of silica aerogels were investigated based on the analysis results of SEM,specific surface area,pore size distribution,X-ray diffraction,XPS and infrared spectroscopy.

关键词： Pyrolysis Thermodynamics Reaction kinetics

Adaptive observer-based integral event-triggered antivibration control of a full aircraft active landing gear system with irregular runway excitations

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Science China(Information Sciences) 2024年第6期67卷 248-261页

作者： Wenxiao HU Chenglong du Fanbiao LI Xinmin CHEN chunhua YANG Weihua GUI School of Automation Central South University Research Center in System Engineering for Special Aircrafts Ningbo Institute of Materials Technology and EngineeringChinese Academy of Sciences

This study addresses the antivibration issue of a full aircraft active landing gear system(LGS)under landing impact and runway excitations via a novel adaptive observer-based integral event-triggered control method. First, a full aircraft active LGS comprising a front gear and two synchronized main left and right gears with active suspensions is established, where the information exchange among them is not implemented directly. Second, two adaptive observers are designed separately for the front and main LGSs to identify the varying damping parameters and estimate the system states simultaneously. Third, estimated states are transmitted to a shared network through a novel integral event-triggered mechanism(I-ETM);thus, the front and main LGSs are interconnected, and a networked control scheme for the aircraft LGS is constructed. Additionally, the integrated active control law is designed with the aid of the transmitted states of the front and main LGSs, enhancing the robustness against the pitch vibration of the ***, the L2-stability of the hybrid system is guaranteed to depress the vertical vibration effect of the landing impact and irregular runway excitations, thus improving passenger safety and comfort. Moreover,a codesign method is provided to obtain feasible solutions to the gain matrices of the observers and controllers simultaneously. Simulation and comparison results are presented to illustrate the effectiveness and superiority of the proposed control scheme in antivibration and saving communication resources.

关键词： aircraft active landing gear antivibration control integral event-triggered mechanism adaptive observer ${\mathcal{L}}_2$-stability