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Spatial light modulation for femtosecond laser manufacturing:Current developments and challenges

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Science China(Technological Sciences) 2024年第1期67卷 60-72页

作者： ZANG Xue LIU ZiTing XU yishi wang Yi wang Qing LI ZhenZe wang Lei State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China State Key Laboratory of Precision Measurement and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084China

Since the invention of lasers,spatial-light-modulated laser processing has become a powerful tool for various *** enables multidimensional and dynamic modulation of the laser beam,which significantly improves the processing efficiency,accuracy,and flexibility,and presents wider prospects over traditional mechanical technologies for machining three-dimensional,hard,brittle,or transparent *** this review,we introduce:(1)The role of spatial light modulation technology in the development of femtosecond laser manufacturing;(2)the structured light generated by spatial light modulation and its generation methods;and(3)representative applications of spatial-light-modulated femtosecond laser manufacturing,including aberration correction,parallel processing,focal field engineering,and polarization ***,we summarize the present challenges in the field and possible future research.

关键词： femtosecond laser manufacturing spatial light modulation structured light aberration correction parallel processing focal field engineering polarization control

Building Guastavino dome in China： A historical survey of the dome of the Auditorium at Tsinghua University

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Frontiers of Architectural Research 2014年第2期3卷 121-140页

作者： yishi Liu School of Architecture Tsinghua University Beijing 100084 China

Established in 1909, Tsinghua Co[lege was built on the base of a royal garden, and developed into a modern university through campus designs produced by Henry Murphy. The Auditorium, one of the Four Grand Buildings during Tsinghua＇s formative times, was a significant part of early construction and has become a symbol of the school. However, no thorough measuring work has ever been done to it since its completion in 1921. This paper delves into archives with combination of field survey and measurement, aiming to better understand the historical background in which the construction of the Auditorium was embedded, and technological and structural features of the Auditorium. Though the Guastavino system was indicated in the original design drawn by Murphy, concrete shell was applied in the end. The first part combs up the intellectual origins and precedents of the campus planning by Henry Murphy. As the dome is a focal point of the study, a brief course on the history of dome construction in the West is needed. The third part, based upon field measurement in July 2013, compares the actual dome with its original design featured by the Guastavino method, deducing possible reasons that resulted in the differences, including architect＇s unfamiliarity with Guastavino Company and its parameters, considerations about cost, and local construction tradition.

关键词： Guastavino system Dome Tsinghua University The Auditorium Structure

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碳纤维复合材料结构件自然老化试验研究

化工新型材料 2018年第4期46卷 63-65页

作者：张海燕李根臣王义师刘亚平邵蒙刘震宇刘晓飞魏化震山东非金属材料研究所济南250031

在自然环境条件下,从表观、力学性能以及内部结构对碳纤维复合材料结构件(CFRP)在海南省万宁市、黑龙江省漠河县以及山东省济南市3个储藏地进行了12a的老化性能研究,利用扫描电子显微镜、CT探测仪以及电子万能试验机等分析研究了结构件... 详细信息

在自然环境条件下,从表观、力学性能以及内部结构对碳纤维复合材料结构件(CFRP)在海南省万宁市、黑龙江省漠河县以及山东省济南市3个储藏地进行了12a的老化性能研究,利用扫描电子显微镜、CT探测仪以及电子万能试验机等分析研究了结构件的微观形貌、内部结构变化以及结构件承载性能。结果表明,该结构件经过12a的自然老化后,表面光滑,没有裸露纤维,并且没有降解老化现象,内部结构和力学性能非常稳定,不受储藏地域及时间的影响,挠度值保持在15.3~18.1mm之间,离散系数只有0.05。

关键词：碳纤维复合材料结构件自然老化微观形貌力学性能内部质量

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MC尼龙聚合过程热效应研究

化工新型材料 2021年第5期49卷 162-165页

作者：邵蒙刘晓飞李海柱刘震宇张海燕王义师李根臣山东非金属材料研究所济南250031 济南北方泰和新材料有限公司济南250033

采用静态浇铸法制备了单体浇铸尼龙(MC尼龙),使用智能巡检仪对聚合过程热效应引起的温度变化进行了采集,对比了催化剂用量对聚合热效应的影响,并对温度-时间曲线进行了拟合。结果表明,温度变化曲线呈明显的S状,根据斜率变化可分为三个阶... 详细信息

采用静态浇铸法制备了单体浇铸尼龙(MC尼龙),使用智能巡检仪对聚合过程热效应引起的温度变化进行了采集,对比了催化剂用量对聚合热效应的影响,并对温度-时间曲线进行了拟合。结果表明,温度变化曲线呈明显的S状,根据斜率变化可分为三个阶段,其中最高聚合温度约199℃,最大温升约55℃;催化剂用量增加对提高聚合速率表现出先快后慢的趋势;运用Boltzmann函数拟合MC尼龙聚合过程温度变化优度较高。

关键词：单体浇铸尼龙热效应催化剂活化剂

Integrated fault estimation and fault-tolerant control for a flexible regional aircraft

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Chinese Journal of Aeronautics 2022年第3期35卷 390-399页

作者： yishi LIU Sheng HONG Enrico ZIO Jianwei LIU School of Cyber Science and Technology Beihang UniversityBeijing 100191China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Department of Energy Politecnico di MilanoMilano 20133Italy MINES ParisTech PSL Research UniversityCRCSophia Antipolis 06904France Eminent Scholar Department of Nuclear EngineeringCollege of EngineeringKyung Hee UniversitySeoul 02447South Korea

The article focuses on the design and application of an active reconfigurable controller that mitigates the effects of gust load and actuator faults on a flexible aircraft.A novel integrated adaptive output feedback scheme is investigated to address the actuator *** real-time fault values provided by the fault estimation module are considered in the reconfigurable control law to improve the fault-tolerant *** estimate values of faults and control gains are calculated by analyzing the stability of the overall *** proposed controller is simulated using a flexible aircraft model with a discrete‘1-cosine’gust,and the results show that it can effectively mitigate the wing root moments and recover the flight maneuver stability after the aircraft suffered from gusts.

关键词： Adaptive control Fault estimation Fault-tolerant control Flexible aircraft Gust load Integrated strategy

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飞行器承力结构件材料与结构研究

化工新型材料 2019年第5期47卷 123-126页

作者：张海燕李根臣刘震宇刘晓飞王义师邵蒙郑志才魏化震山东非金属材料研究所济南250031

采用纤维增强环氧树脂复合材料固化成型制得实心承力结构件和空心承力结构件。对承力结构件的应变量、质量以及外观方面进行了探究。制得的实心承力结构件和抽芯中空承力结构件外观良好,表面光滑,没有麻点、裂纹等缺陷;而轻木夹芯承力... 详细信息

采用纤维增强环氧树脂复合材料固化成型制得实心承力结构件和空心承力结构件。对承力结构件的应变量、质量以及外观方面进行了探究。制得的实心承力结构件和抽芯中空承力结构件外观良好,表面光滑,没有麻点、裂纹等缺陷;而轻木夹芯承力结构件和泡沫夹芯承力结构件工艺性差,结构件表面出现不同程度的麻点,有凹坑、缺料等现象。抽芯空心承力结构件的应变量、质量分别为0.72mm、208g,比实心承力结构件的应变量增加了22.03%,质量减少了21.51%,但是抽芯空心承力结构件的内部品质仍需进行深入的研究。

关键词：承力结构件碳纤维实心结构夹芯结构中空结构应变量

Multiple evidences indicate no relationship between prehistoric disasters in Lajia site and outburst flood in upper Yellow River valley, China

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Science China Earth Sciences 2018年第4期61卷 441-449页

作者： DONG GuangHui ZHANG FanYu LIU FengWen ZHANG DongJu ZHOU AiFeng YANG yishi wang GongHui MOE Key Laboratory of Western China's Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou University Key Laboratory of Mechanics on Disaster and Environment in Western China (Ministry of Education) Department of Geological EngineeringLanzhou University Research Center on Landslides Disaster Prevention Research InstituteKyoto University

All around the world, ancient legends exist about the Great Flood, and the influence of the Great Flood in human evolutionary history is a hotly debated topic. In China, the legend of the prehistoric Great Flood and Yu the Great's flood control has a long history and is considered to be closely linked to the establishment of the Xia Dynasty. However, there is a lack of solid scientific evidence. Against this issue, some scholars have proposed that an earthquake around 1920 BCE in the Guanting Basin along the upper reaches of the Yellow River led to the creation of a lake by damming in the Jishi Gorge and that the outburst of water from that lake led to the massive flood in the Yellow River region. These studies provided new scientific evidence for the Chinese legend. In this paper, we date skeletal samples embedded in earthquake sand blasting from the Lajia site, analyze remains from natural disasters(such as earthquakes and floods) and also archaeological remains. In addition, we compared the skeletal samples dating with that of sediments from the dammed-up lake. Our results are inconsistent with those of previous scholars. The earthquake at the Lajia site occurred no earlier than 1800 BCE, and the dammed-up lake in Jishi Gorge had disappeared by 3600 BCE. Thus, the formation and outburst of the dammed lake, the sudden death of ancient humans at the Lajia site and the ancient earthquake were independent events occurring at different times. In addition, the massive flood in the upper reaches of the Yellow River did not actually happen. Thus, we argue against and invalidate the hypothesis that the massive flood was related to Yu the Great's flood control and the establishment of the Xia Dynasty.

关键词： Guanting Basin Qijia culture Lajia site Earthquake Outburst flood The establishment of the Xia dynasty

A chronology of the field of modern Chinese architectural history, 1986-2012

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Frontiers of Architectural Research 2013年第2期2卷 191-208页

作者： yishi Liu School of Architecture Tsinghua University Beijing 100084 Chine

The research of modern Chinese architectural history formally started in the mid-1980s and the first conference held in 1986 in Beijing marks the establishment of the field. Over the past 26 years, this emerging field has developed fast and steadily. As a result, thirteen biennia[ conferences have been held since 1986, and academic products of various forms with over ten million characters have been published. This article surveys the development of modern Chinese architectural history as a field of scholarly inquiry in China and outlines some of keystone events in the past 26 years. It also charts out how some key concepts of the field, such as timetine, geography and research approaches have been evotving over time. The article introduces some of the most significant studies in modern Chinese architectural history from the middle 1980s to the present.

关键词： Modern Chinesearchitectural history Chronology Early modern times Method

Distributed state estimation for heterogeneous mobile sensor networks with stochastic observation loss

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Chinese Journal of Aeronautics 2022年第2期35卷 265-275页

作者： Yingrong YU Jianglong YU yishi LIU Zhang REN Science and Technology on Aircraft Control Laboratory School of Automation Science and Electrical EngineeringBeihang.UniversityBeijing 100191China

The problem of distributed fusion and random observation loss for mobile sensor networks is investigated *** view of the fact that the measured values,sampling frequency and noise of various sensors are different,the observation model of a heterogeneous network is constructed.A binary random variable is introduced to describe the drop of observation component and the topology switching problem caused by complete observation loss is also considered.A cubature information filtering algorithm is adopted to design local filters for each observer to suppress the negative effects of measurement *** derive a consistent and accurate estimation result,a novel weighted average consensus-based filtering approach is put *** the sensor that suffers from observation loss,its local prediction information vector is fused with the information contribution vectors of the neighbors to obtain the local *** the consensus weight matrix is designed for consensus-based distributed collaborative information *** boundness of the estimation errors is proved by employing the stochastic stability *** the end,two numerical examples are offered to assert the validity of the presented method.

关键词： Consistency theorem Heterogeneous sensor networks Information fusion State estimation Stochastic boundedness