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target alignment in the Shen-Guang Ⅱ Upgrade laser facility

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High Power Laser Science and Engineering 2018年第1期6卷 58-66页

作者： Lei Ren Ping Shao Dongfeng Zhao Yang Zhou Zhijian Cai Neng Hua Zhaoyang Jiao Lan Xia Zhanfeng Qiao Rong Wu Lailin Ji Dong Liu Lingjie Ju Wei Pan Qiang Li Qiang Ye Mingying Sun Jianqiang Zhu Zunqi Lin National Laboratory on High Power Laser and Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of Sciences Key Laboratory of High Power Laser and Physics Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai Institute of Laser Plasma China Academy of Engineering Physics

The Shen-Guang II Upgrade(SG-Ⅱ-U) laser facility consists of eight high-power nanosecond laser beams and one shortpulse picosecond petawatt laser. It is designed for the study of inertial confinement fusion(ICF), especially for conducting fast ignition(FI) research in China and other basic science experiments. To perform FI successfully with hohlraum targets containing a golden cone, the long-pulse beam and cylindrical hohlraum as well as the short-pulse beam and cone target alignment must satisfy tight specifications(30 and 20 μm rms for each case). To explore new ICF ignition targets with six laser entrance holes(LEHs), a rotation sensor was adapted to meet the requirements of a three-dimensional target and correct beam alignment. In this paper, the strategy for aligning the nanosecond beam based on target alignment sensor(TAS) is introduced and improved to meet requirements of the picosecond lasers and the new six LEHs hohlraum targets in the SG-II-U facility. The expected performance of the alignment system is presented, and the alignment error is also discussed.

关键词： laser drivers petawatt lasers spherical hohlraum target alignment target area

Admissible model noise upper bound with constraint of stochastic passage characteristics

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Journal of Systems Engineering and Electronics 2011年第4期22卷 565-571页

作者： Guoqing Qi Yinya Li Li Chen Andong Sheng Automation School Nanjing University of Science and Technology Nanjing 210094 P. R. China Artillery & Air Defence Forces Institute of Equipment & Technologies Headquarters of the General Equipment of PLA Beijing 100012 P. R. China

In some object tracking systems, the moving object future position is an area （i.e., target area）. It is a successful estimation strategy if the predicted points fall in the target area. If the object makes a sudden maneuvering, the prediction may get out of the target area easily which may make the tracking system lose the object. The aim is to investigate the admissible maximum object maneuvering intensity, which is characterized as model noise variance, for such kind of tracking system. Firstly, the concept of stochastic passage characteristics over the boundary of target area and their relationship with prediction error variance are described. Secondly, the consistency among the indices of regional pole, prediction error variance and stochastic passage characteristics is analyzed. Thirdly, the multi-indices constraints are characterized by a set of bi-linear matrix inequalities （BMIs）. Then, the admissible maximum model noise variance and the satisfactory estimation strategy are presented by iteratively solving linear matrix inequalities （LMIs） to approximate BMIs. Finally, a numerical example is proposed to demonstrate the obtained resuits.

关键词： stochastic passage characteristic target area modelnoise bi-linear matrix inequality (BMI).

Operational Plan,Effect Verification,and Key Technical Settings for a Stadium-Scale Artificial Rain Reduction Experiment

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Journal of Meteorological Research 2023年第5期37卷 643-665页

作者： Yuquan ZHOU Siyao LIU Miao CAI Junlin LONG Jia WANG CMA Cloud–Precipitation Physics and Weather Modification Key Laboratory(CPML) Weather Modification CentreChina Meteorological Administration(CMA)Beijing 100081 School of Electronic Engineering Chengdu University of Information TechnologyChengdu 610225 College of Meteorological Observation Chengdu University of Information Technology/CMA Key Laboratory of Atmospheric SoundingChengdu 610225 Jiangsu Weather Modification Center Nanjing 210000

To explore the key technologies of artificial weather modification for specific targets(e.g.,a stadium)and improve the efficiency of artificial rainfall modification for major events,this study conducts an artificial rainfall reduction experiment for the closing ceremony of Nanjing Youth Olympic Games on 28 August *** retrievals,radar observations,sounding data,and other sources of information as well as Cloud and Precipitation Accurate Analysis System(CPAS)are used in this *** main conclusions are as follows.(1)On 28 August 2014,a large-scale cumulus cloud system with mixed-phase stratocumulus and stratus precipitation was *** system was influenced by the weak shear of a low-level trough and the precipitation was dominated by cold clouds with dry layers between ***,we adopted the crystal-priming over-catalytic hypothesis and conducted a rocket-catalytic rain abatement operation at a certain distance(100–25 km)from the *** shootings of different intensities were implemented for two echoes that affected the stadium successively(two rounds of 15 rocket shootings within15 min for an isolated weak echo IA;multiple rounds of 156 rocket shootings within 80 min for a strong echo IB).Amazingly,after the shootings with the catalysis in the air,reflectivity of the two echoes was reduced at all altitudes with the most significant reduction at the 2-km altitude,and the time needed for the obvious reduction was 40 *** most obvious reduction of the two echoes then maintained for 60 and 53 min,respectively,and the operation time needed for the echo zone to recover after the stop of rocket shooting was 108 min for echo IA and 90 min for echo *** two echoes moving across the stadium during the time period of the closing ceremony(2000–2130 local time)were at their minimal strengths,with almost no echo over the target *** demonstrates that the rocket shooting strategy of over-crystallization catalysis is effective,and th

关键词： target area artificial rainfall abatement radar monitoring weather modification plan effect analysis

Value of preoperative magnetic resonance imaging measurements in thoracic percutaneous vertebroplasty using unilateral puncture

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Chinese Medical Journal 2010年第21期123卷 2983-2988页

作者： MA Xin WANG Li-xun WANG Hong-li JIANG Li LU Fei-zhou JIANG Jian-yuan Department of Orthopedics Huashan Hospital Fudan University Shanghai 200040 China

Background Increasing the successful puncture rate of the percutaneous vertebroplasty （PVP） in thoracic vertebral compression fracture by unilateral puncture is a problem that spinal surgeons are trying to solve. The aim of this study was to assess the value of preoperative MRI imaging measurements for PVP using a unilateral *** We performed a retrospective, comparative study of two groups of osteoporotic thoracic vertebral compression fracture patients who had received a PVP using a unilateral puncture. Group A （22 patients with 27 valid vertebrae） received PVP with a unilateral puncture between October 2005 and February 2007. Group B （18 patients with 24 valid vertebrae） received a routine MRI imaging measurements before a PVP between March 2007 and June *** determined the target area to puncture based on the preoperative MRI cross-sectional images of vertebra. The PVP used a simultaneous puncture through a unilateral posterolateral approach, so the vertical distance from the point of skin puncture to the posterior median line, as well as the puncture angle, were measured using the MRI. The results were used to guide the PVP operation. We compared these two groups based on the average time for a single vertebra operation, the achievement ratio of puncture, and the incidence of bone cement leakage during surgery. The mean follow-up period was 14.2 months （range 12-23 months）. The pre- and post-operative visual analogue score （VAS）（3and 12 months post-surgery）, the variation of Oswestry disability index （ODI） and the incidence of long-term complications were also *** The average time of a single vertebra operation in groups A and B were （34.7±5.4） and （23.3±4.2） minutes,respectively. In groups A and B, the success rates of puncture were 74.1% and 91.7%, respectively. Postoperative reduction of the average VAS scores in groups A and B at 3 and 12 months post-surgery were 5.8±2.1, 6.1±1.8, 6.1 ±2.0,6.2±1.6, respectively. However, the ODI

关键词： percutaneous vertebroplasty operation significant difference PVP compression vertical distance time fracture test evaluation MRI results target area median line comparative bone cement successful study based VAS

The Study on Upper Bound of Measurement Error with Constraint of Stochastic Passage Characteristics

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The Study on Upper Bound of Measurement Error with Constrain...