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Current Oscillation and dc-Voltage-Controlled Chaotic Dynamics in Semiconductor Superlattices

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Communications in Theoretical Physics 2006年第2期45卷 363-368页

作者： WANG chang lu Jing-Tao State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology the Chinese Academy of Sciences Shanghai 200050 China

We report a detailed theoretical study of current oscillation and de-voltage-controlled chaotic dynamics in doped GaAs/AlAs resonant tunneling superlattices under crossed electric and magnetic fields. When the superlattice is biased at the negative differential velocity region, current self-oscillation is observed with proper doping concentration. The current oscillation mode and oscillation frequency can be affected by the dc voltage bias, doping density, and magnetic field. When an ac electric field with fixed amplitude and frequency is also applied to the system, different nonlinear properties show up in the external circuit with the change of dc voltage bias. We carefully study these nonlinear properties with different chaos-detecting methods.

关键词： semiconductor superlattices current oscillation chaotic dynamics

Plantation transformation alternatives determine carbon sequestration capacity – a case study with Pinus massoniana in southern China

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Journal of Mountain Science 2020年第4期17卷 919-930页

作者： RUAN lu-ping lu Yuan-chang MENG Jing-hui Research Center of Forest Management Engineering of National Forestry and Grassland Administration Beijing Forestry UniversityBeijing 100083China Institute of Forest Resource and Information Techniques Chinese Academy of ForestryBeijing 100091China

It is widely accepted that global warming, which results from the increase of carbon dioxide(CO2) in the atmosphere, has a negative impact on human beings. Forests are the largest terrestrial ecosystem and play an important role in carbon sequestration. Many studies have documented that a mixed-species forest can sequester more carbon than single species forests, depending on the site conditions. Therefore, uneven-aged mixed-species forest management has been receiving more and more attention. In 2008, an experiment with five silvicultural models for Pinus massoniana(Chinese red pine) plantation, i.e., four transformation treatments(A1-A4) and one control treatment(A5) was conducted in the Experimental Center of Tropical Forestry of Chinese Academy of Forestry in Pingxiang City, in southwestern Guangxi Zhuang Autonomous Region, southern China. The four transformation treatments(A1-A4) enriched Castanopsis hystrix, Manglietia glance, Erythrophleum fordii and Quercus griffithii with differed richness and composition after thinning(removed 70% of trees), while no silvicultural treatment was used in the control treatment A5. In this study, we compared the carbon sequestration capacity of these five silvicultural models based on periodic annual increment and growth rate. Our results indicated that all the transformation treatments performed significantly better in carbon sequestration than the control treatment. A significant difference was also observed amongst the transformation treatments. Moreover, the transformation treatment A1 with enrichment species Castanopsis hystrix(350 trees·ha^-1) and Manglietia glance(350 trees·ha^-1) was determined to be the optimal model for maximum carbon sequestration because of its high tree-level growth rate and high economic value of enriched plantings, which could be popularized in other places. Our results further confirmed that management using mixed-species forests is a better approach to combat climate change than using monocult

关键词： Global warming Carbon sequestration Mixed-species forest Silvicultural model Singlespecies(monoculture)forest

Dosimetric risk factors for radiation esophagitis in patients with breast cancer following regional nodal radiation

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World Journal of Clinical Cases 2024年第17期12卷 2995-3003页

作者： Mei-Chen Ji Zhi-Jia Li Ke Li Yun-Xiao Wang Bo Yang Lin-Lin Lv Ying Su Zhi-Wei Zhang Zhong-Chao Huo Qing Qi Yong-chang lu Zhi-Qiang Cui Yan-Bao Liu Oncology Center The Affiliated Hospital of Hebei University of EngineeringHandan 056002Hebei ProvinceChina General Surgery Department Handan First HospitalHandan 056002Hebei ProvinceChina Department of Breast Surgery The Affiliated Hospital of Hebei University of EngineeringHandan 056002Hebei ProvinceChina School of Clinical Medicine Hebei University of EngineeringHandan 056002Hebei ProvinceChina

BACKGROUND Radiation esophagitis(RE)is one of the most common clinical symptoms of regional lymph node radiotherapy for breast ***,there are fewer studies focusing on RE caused by hypofractionated radiotherapy(HFRT).AIM To analyze the clinical and dosimetric factors that contribute to the development of RE in patients with breast cancer treated with HFRT of regional lymph *** Between January and December 2022,we retrospectively analysed 64 patients with breast cancer who met our inclusion criteria underwent regional nodal intensity-modulated radiotherapy at a radiotherapy dose of 43.5 Gy/*** Of the 64 patients in this study,24(37.5%)did not develop RE,29(45.3%)developed grade 1 RE(G1RE),11(17.2%)developed grade 2 RE(G2RE),and none developed grade 3 RE or *** univariable logistic regression analysis found G2RE to be significantly correlated with the maximum dose,mean dose,relative volume 20-40,and absolute volume(AV)*** stepwise linear regression analyses found AV30 and AV35 to be significantly associated with G2RE(PluSION AV30 and AV35 were significantly associated with *** thresholds for AV30 and AV35 should be limited to 2.39 mL and 0.71 mL,respectively.

关键词： Breast cancer Dosimetric parameters Radiation esophagitis Esophagitis Hypofractionated radiotherapy

融合自适应滑动集合经验模态分解的机器学习月径流预测方法

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水电能源科学 2024年第10期42卷 6-10页

作者：胡永旭乔长录刘延雪李旭石河子大学水利建筑工程学院新疆石河子832000 寒旱区生态水利工程兵团重点实验室新疆石河子832000

为提高月径流预测精度,解决传统分解集成径流预测方法提前引入“未来信息”在实际工程中无法实现的问题,提出了一种基于自适应滑动集合经验模态分解(ASEEMD)、秃鹰搜索(BES)算法和极限学习机(ELM)耦合的月径流预测模型(ASEEMD-BES-ELM)... 详细信息

为提高月径流预测精度,解决传统分解集成径流预测方法提前引入“未来信息”在实际工程中无法实现的问题,提出了一种基于自适应滑动集合经验模态分解(ASEEMD)、秃鹰搜索(BES)算法和极限学习机(ELM)耦合的月径流预测模型(ASEEMD-BES-ELM)。并以玛纳斯河1957~2014年的月径流序列为例,首先,利用ASEEMD对原始月径流序列自适应分解,得到若干子序列;其次,将各子序列分别输入到结合BES算法和网格搜索优化后的ELM模型中预测;最后,累加各子序列预测结果,得到最终月径流预测值。与ELM^(*)、BES-LEM^(*)、BES-ELM、EEMD-BES-ELM(传统“捆绑分解”)模型对比结果表明,ASEEMD-BES-ELM模型的纳什效率系数为0.971、平均绝对误差为5.173m^(3)/s、均方根误差为8.282m^(3)/s、平均绝对百分比误差为16.033%,在符合实际应用中预测精度最高。结果可为干旱区月径流预测研究提供参考。

关键词：月径流预测自适应分解集合经验模态分解秃鹰搜索算法极限学习机玛纳斯河

光电导航防疫消杀机器人系统设计及协同路径规划

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制造业自动化 2024年第7期46卷 64-69页

作者：路畅邬盼盼马佳沈阳航空航天大学航空宇航学院辽宁沈阳110136 沈阳航空航天大学自动化学院辽宁沈阳110136 沈阳航空航天大学理学院辽宁沈阳110136

针对人工和消杀机器人防疫消杀过程中效率低、精度低等问题,提出并设计基于光电导航技术的防疫消杀系统。设计履带运动系统和喷洒消杀系统,研究基于编码器、陀螺仪等传感器的光电导航技术和基于蚁群算法、节点顺序访问算法及粒子群算法... 详细信息

针对人工和消杀机器人防疫消杀过程中效率低、精度低等问题,提出并设计基于光电导航技术的防疫消杀系统。设计履带运动系统和喷洒消杀系统,研究基于编码器、陀螺仪等传感器的光电导航技术和基于蚁群算法、节点顺序访问算法及粒子群算法的多车路径规划方法。最后在实验室模拟场景中进行样机试验。结果表明:两辆样机在无碰撞的同时合理分配消杀任务、依次经过各个消杀节点,并能通过识别节点的地面信标进行消杀作业,验证了设计方案的可靠性和有效性。

关键词：防疫消杀光电导航技术路径规划消杀车集群任务分配

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公石松多糖的提取、结构表征及生物活性研究

福建分析测试 2024年第3期33卷 1-5,11页

作者：张颖王长露翁文闽南师范大学化学化工与环境学院福建漳州363000 漳州城市职业学院福建漳州363000

以公石松为原料,通过水提醇沉法获得公石松多糖。利用高效凝胶渗透色谱、柱前衍生化HPLC法、紫外、红外光谱、刚果红实验等对公石松多糖的结构进行了表征,通过抗氧化实验评估公石松多糖的体外抗氧化活性,采用MTT法初步探讨了其对肝癌细... 详细信息

以公石松为原料,通过水提醇沉法获得公石松多糖。利用高效凝胶渗透色谱、柱前衍生化HPLC法、紫外、红外光谱、刚果红实验等对公石松多糖的结构进行了表征,通过抗氧化实验评估公石松多糖的体外抗氧化活性,采用MTT法初步探讨了其对肝癌细胞HepG2、肝细胞LO2的抑制效果。结果表明,公石松多糖的相对分子量分布于50325~115144 Da,由甘露糖、葡萄糖、半乳糖和阿拉伯糖组成,具有三螺旋结构。体外抗氧化活性测定显示,公石松多糖对DPPH、ABTS、羟基自由基表现出较强的清除能力。抗肿瘤实验表明,公石松多糖具有抑制HepG2增殖的能力。

关键词：公石松多糖结构表征抗氧化活性生物活性

新文科建设背景下高校课程变革:目标、困境与进路

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民族高等教育研究 2024年第5期12卷 54-60页

作者：拓丹丹卢长娥四川师范大学马克思主义学院四川成都610066 淮南师范学院教育学院安徽淮南232038

新文科背景下高校课程建设是一场教育质量的变革,其核心在于立足中国特色社会主义新时代,融通古今中外之文化与科技,创新发展中华优秀传统文化,吸纳世界优秀文化,在时代脉搏中提升国家文化软实力。当前,高校课程建设面临诸多困境,如文... 详细信息

新文科背景下高校课程建设是一场教育质量的变革,其核心在于立足中国特色社会主义新时代,融通古今中外之文化与科技,创新发展中华优秀传统文化,吸纳世界优秀文化,在时代脉搏中提升国家文化软实力。当前,高校课程建设面临诸多困境,如文科课程教育的式微,学科分化后的壁垒高墙以及课程内容的陈旧等。基于此,从理论和实践的交互论证中探究新文科背景下高等教育课程建设的突破路径,在理论上阐述其变革的可能性、必然性、循序性;从实践上探究课程目标、课程内容、课程实施及其教学模式的转变与革新。

关键词：新文科建设课程课程融合实践逻辑

Confinement characteristic of primary electrons with the variation of channel width in the discharge chamber of annular ion thruster

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Chinese Journal of Aeronautics 2021年第5期34卷 79-92页

作者： chang lu Guangqing XIA Bin SUN Yajie HAN State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of TechnologyDalian 116024China Key Laboratory of Advanced Technology for Aerospace Vehicles of Liaoning Province Dalian University of TechnologyDalian 116024China

In this paper,the confinement characteristic of primary electrons in the non-axisymmetric discharge chamber of annular ion thruster is investigated by a three-dimensional(3 D)non-self-consistent particle tracking model with Monte Carlo Collision(MCC)*** results show that:The density of primary electrons upstream of ion optics on cathode axis is about 5–50 times higher than that of the other side,which means that the density of primary electrons is obviously *** channel width has a significant effect on the average density and uniformity of primary *** average density can be increased by nearly 1.5 times under the appropriate channel width,meanwhile,the variance of density distribution can be reduced by more than 2 *** is because that increasing the channel width can improve the average confinement length of primary electrons ***,there is an infection point in the increase of primary electron average confinement length with the channel width,which caused by the significant change of magnetic field *** the case after the inflection point,primary electron mainly(more than 50%)moves to the channel center,which makes the average confinement length of primary electrons and their number in the discharge chamber increase largely.

关键词： Annular ion thruster Average confinement length Electric propulsion Ion thruster Primary electrons

Ke Hsin Kuo:A distinguished scientist and great mentor

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Protein & Cell 2019年第2期10卷 79-86页

作者： Da-Neng Wang lu-chang Qin Skirball Institute of Biomolecular Medicine and Department of Cell BiologyNew York University School of Medicine540 First AvenueNew YorkNY 10016USA W.M.Keck Laboratory for Atomic Imaging and Manipulation Department of Physics and AstronomyUniversity of North CarolinaChapel HillNC 27599USA

Early years Professor Ke Hsin Kuo was bom in Beijing in 1923,and his childhood was spent in Harbin in northemstem China where his father worked as an engineer to build the local *** early education was at best characterized by frequent disruptions,the first of which being the"9.18 Incidenf of 1931 when the Japanese Kwantung Army launched an assault in Shenyang(Mukden)on the local Chinese troops and quickly took control of all the Northeastern Provinces(Manchuria).He moved to Tianjin in the spring of 1936,where he continued his education by enrolling in the famous Nankai High ***,his school life at Nankai was soon disrupted again by the eruption of full-scale war in July of 1937 after Japan attacked and occupied *** with his brothers,he fled to join his parents who had previously relocated to *** studied in Chongqing for four more years to complete his high school education,during which classes were constantly being disrupted due to the frequent bombings of the city by Japanese *** bombings not only left him with long lasting memories of the war,but also bore him a permanent burn scar on his back as a result of a bomb that exploded just meters away from him.

关键词： Professor childhood Manchuria