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Double hard X-ray peaks in RHESSI flares as evidence of chromospheric evaporation and implications for modifying the Neupert effect

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Research in Astronomy and Astrophysics 2009年第10期9卷 1155-1164页

作者： You-Ping Li wei-qun Gan Yang Su Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 China

Among the RHESSI flare samples, we concentrated on a kind of flare that presents two successive peaks （that is, it presents both an impulsive phase and a gradual phase） in 12 - 25 keV light curves. Taking the C1.4 flare on 2002 August 12 as an example, we studied the light curves, spectra, and images in detail. Making full use of the capabilities of RHESSI, we showed some evidence to support the expected causal relationship between these two peaks; the first peak is mainly nonthermal, while the second peak is mainly thermal; the energy carried by nonthermal electrons during the first peak seems to be comparable to the thermal energy of the second peak. The morphologies of X-ray images and their evolutions provide additional evidence for this causality. We conclude that two such peaks in the 12 - 25 keV light curve are good evidence for the chromospheric evaporation. However, the maximum time of the second peak is later than the end time of the first peak, suggesting that for some events, a modification of the traditional Neupert effect could be necessary by inclusion of a time delay, which might be partly related to the filling of the loop by evaporated material.

关键词： Sun flares -- Sun X-rays, gamma-rays

Mechanical Response of Single Plant Cells to Cell Poking:A Numerical Simulation Model

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Journal of Integrative Plant Biology 2006年第6期48卷 700-705页

作者： Rong Wangt qun-Ying Jiao De-Qiang wei College of Sciences China Agricultural University Beijing 100083 China Electronic Machinery and Transportation Engineering Department Guilin University of Electronic Technology Guilin 541004 China

Cell poking is an experimental technique that is widely used to study the mechanical properties of plant cells. A full understanding of the mechanical responses of plant cells to poking force Is helpful for experimental work. The aim of this study was to numerically investigate the stress distribution of the cell wall, cell turgor, and deformation of plant cells in response to applied poking force. Furthermore, the locations damaged during poking were analyzed. The model simulates cell poking, with the cell treated as a spherical, homogeneous, isotropic elastic membrane, filled with incompressible, highly viscous liquid. Equilibrium equations for the contact region and the non-contact regions were determined by using membrane theory. The boundary conditions and continuity conditions for the solution of the problem were found. The forcedeformation curve, turgor pressure and tension of the cell wall under cell poking conditions were obtained. The tension of the cell wall circumference was larger than that of the meridian. In general, maximal stress occurred at the equator around. When cell deformation increased to a certain level, the tension at the poker tip exceeded that of the equator. Breakage of the cell wall may start from the equator or the poker tip, depending on the deformation. A nonlinear model is suitable for estimating turgor, stress, and stiffness, and numerical simulation is a powerful method for determining plant cell mechanical properties.

关键词： cell poking cell wall tension force-deformation relationships plant cell turgor pressure

Determination of Residual Acrylamide in Medical Polyacrylamide Hydrogel by High Performance Liquid Chromatography tandem Mass Spectroscopy

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Biomedical and Environmental Sciences 2009年第1期22卷 28-31页

作者： wei-wei LI HUI LI ZHI-FEI LIU qun QIAO Department of Plastlc and Cosmetic Surgery Pekmg Union Medical College Hospital Chinese Academy of Medical Sciences Beijing 100032 China Department of Ecsomatics Beijing Health School Beijing 100053 China

Objective To determine residual acrylamide in medical polyacrylamide hydrogel by high performance liquid chromatography tandem mass spectroscopy （HPLC-MS）. Methods After 13C3 labeled acrylamide was added, the sample was extracted with water and then cleaned up with ExtrelutTM 20. The polyacrylamide hydrogel sample and 20 clinical cases were analyzed by HPLC-MS/MS and isotope dilution quantifying technique in selected reaction monitoring （SRM） mode. Results Acrylamide was separated from polyacrylamide hydrogel. The concentration of acrylamide in polyacrylamide hydrogel ranged from 3.9×10^-9 to 3.1×10^- 8g/L in the 20 clinical cases. The peak area was favorable linear and the range was up to 3 000 μg/L. The recovery rate was 103.1% with a relative standard deviation （RSD） of 6.20%, when the mark level was 50 lag/L. Conelusion HPLC-MS is a rapid, accurate, and sensitive method for the determination of residual acrylamide in medical polyacrylamide hydrogel.

关键词： High performance liquid chromatography-mass spectroscopy Polyacrylamide hydrogel Acrylamide

Reducing partition skew on MapReduce: an incremental allocation approach

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Frontiers of Computer Science 2019年第5期13卷 960-975页

作者： Zhuo WANG qun CHEN Bo SUO wei PAN Zhanhuai LI School of Computer Science and Engineering North Western Polytechnical UniversityXi’an 710072 China

MapReduce,a parallel computational model,has been widely used in processing big data in a distributed *** of alternate map and reduce phases,MapReduce has to shuffle the intermediate data generated by mappers to *** key challenge of ensuring balanced workload on MapReduce is to reduce partition skew among reducers without detailed distribution information on mapped *** this paper,we propose an incremental data allocation approach to reduce partition skew among reducers on *** proposed approach divides mapped data into many micro-partitions and gradually gathers the statistics on their sizes in the process of *** micropartitions are then incrementally allocated to reducers in multiple *** propose to execute incremental allocation in two steps,micro-partition scheduling and micro-partition *** propose a Markov decision process (MDP)model to optimize the problem of multiple-round micropartition scheduling for allocation *** present an optimal solution with the time complexity of O(K· N2),in which K represents the number of allocation rounds and N represents the number of ***,we also present a greedy but more efficient algorithm with the time complexity of O(K.N ln N).Then,we propose a minmax programming model to handle the allocation mapping between micro-partitions and reducers,and present an effective heuristic solution due to its ***,we have implemented the proposed approach on Hadoop,an open-source MapReduce platform,and empirically evaluated its *** extensive experiments show that compared with the state-of-the-art approaches,the proposed approach achieves considerably better data load balance among reducers as well as overall better parallel performance.

关键词： incremental partitioning data balance MapReduce

Age and body size of Rana amurensis from northeastern China

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Current Zoology 2011年第6期57卷 781-784页

作者： wei CHEN Xin lu Department of Zoology College of Life Sciences Wuhan University Wuhan 430072 China

Age and body size are two important demographic traits that determine the life history strategies of populations and species. We measured these two parameters ofRana amurensis, at a 900 m and a 500 m altitude site in northeastern China. At the two sites, age at first reproduction was 2 years for males and 3 years for females. The maximum age of males and females at the high-altitude site was 6 and 7 years, and 5 and 7 years at the low-altitude population, respectively. Females were significantly larger than males in both populations, due to greater age in both the high- and low-altitude sites, Body size of either males or fe- males did not differ significantly between populations; only males showed increased body size at the high-altitude site when age effect was statistically controlled for. The increased cline of male body size may be attributable to delayed maturation of the sex due to a shorter growing season at high altitudes

关键词： Age structure, Body size life history Rana amurensis

Interpolation and extrapolation with the CALPHAD method

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Journal of Materials Science & Technology 2019年第9期35卷 2115-2120页

作者： qun luo Cong Zhai Dongke Sun wei Chen Qian Li State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering. Shanghai University & Shanghai Institute of Materials Genome & Materials Genome Institute Shanghai University333 Nanchen RoadShanghai 200444 China School of Mechanical Engineering Southeast UniversityNanjing 211189China Key Laboratory of Power Beam Processing AVIC Manufacturing Technology InstituteBeijing 100024China

It is widely reported that CALPHAD is an extrapolation method when the thermodynamic properties of a multicomponent system are approximated by its *** this work the meaning of the words extrapolation and interpolation is discussed in context of the CALPHAD *** assessing the properties in binary and ternary systems,extrapolation method is indeed often ***,after assessment,the Gibbs energies are in fact interpolated from the lower order systems into the higher order systems in the compositional *** metastable melting temperatures of bcc and hep in Re-W and the liquid miscibility gap in Mg-Zr system are predicted to illustrate the difference between interpolation and extrapolation.

关键词： CALPHAD Interpolation Extrapolation Gibbsenergy

Trajectory and attitude deviations for internal store separation due to unsteady and quasi-steady test method

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Chinese Journal of Aeronautics 2022年第2期35卷 74-81页

作者： wei SONG Jingang DONG wei lu Zenghui JIANG Aerodynamic Science Center China Academy of Aerospace AerodynamicsBeijing 100074China

The deviations of trajectory and attitude angle for internal store separation are evaluated by two wind tunnel test *** is the Freedrop Test(FDT),which is known as unsteady and time-dependent method of scaled *** other is the Captive Trajectory System(CTS)test,which is usually regarded as a quasi-steady and time-averaged test *** result shows that there is a streamwise adverse pressure gradient on the cavity resulting in a nose-up pitching moment coefficient(>0)acting on the store *** the initial pitch angular velocity is 0,the store exits the shear-layer with a nose-up pitch attitude causing the store to climb back towards and collide with the ***,the store passes through the shear-layer into the freestream with a nose-down pitch,which causes a successful separation event when the initial pitch angular velocityludes the aerodynamic force induced by pitch angular velocity whereas the time-averaged method(CTS)cannot reflect the effect of unsteady aerodynamic *** deviation of vertical displacement is not obvious for FDT and CTS test since the store has an initial vertical velocity,which is dominant for the vertical *** means that the highly unsteady flow can create unpredictability in aerodynamic pitching moment of the store,which can lead to the deviation of pitch angle for internal store separation.

关键词： Captive trajectory system Freedrop test Internal weapons Store separation Unsteady test method

A distributed approach for lidar-based relative state estimation of multi-UAV in GPS-denied environments

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Chinese Journal of Aeronautics 2022年第1期35卷 59-69页

作者： Hongming SHEN qun ZONG Hanchen lu Xuewei ZHANG Bailing TIAN Lei HE School of Electrical and Information Engineering Ticmjin UniversityTianjin 300072China Institute of Field Engineering Army Engineering University of PLANanjing 210007China

In this paper,we present a distributed framework for the lidar-based relative state estimator which achieves highly accurate,real-time trajectory estimation of multiple Unmanned Aerial Vehicles(UAVs)in GPS-denied *** system builds atop a factor graph,and only on-board sensors and computing power are *** from the keyframe strategy,each UAV performs relative state estimation individually and broadcasts very partial information without exchanging raw *** complete system runs in real-time and is evaluated with three experiments in different *** results show that the proposed distributed approach offers comparable performance with a centralized method in terms of accuracy and real-time *** flight test demonstrates that the proposed relative state estimation framework is able to be used for aggressive flights over 5 m/s.

关键词： Distributed relative state estimation GPS-denied environments Lidar-based perception Multi-UAV system Pose-graph optimization

Favorable prognosis of female patients with nasopharyngeal carcinoma

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Chinese Journal of Cancer 2013年第5期32卷 283-288页

作者： Xing lu Fei-Li Wang Xiang Guo Lin Wang Hai-Bo Zhang wei-Xiong Xia Si-wei Li Ning-wei Li Chao-Nan Qian Yan-qun Xiang State Key Laboratory of Oncology in South China Department of Nasopharyngeal Carcinoma Sun Yat-sen University Cancer Center

The female sex is traditionally considered a favorable prognostic factor for nasopharyngeal carcinoma (NPC). However, no particular study has reported this phenomenon. To explore the prognostic impact of gender on patients with NPC after definitive radiotherapy, we reviewed the clinical data of 2,063 consecutive patients treated between 1st January 2000 and 31st December 2003 in the Sun Yat-sen University Cancer Center. The median follow-up for the whole series was 81 months. The female and male patients with early stage disease comprised 49.4% and 28.1% of the patient population, respectively. Both the 5-year overall survival (OS) and disease-specific survival (DSS) rates of female patients were significantly higher than those of male patients (OS: 79% vs. 69%, P < 0.001; DSS: 81% vs. 70%, P < 0.001). For patients with locoregionally advanced NPC, the 5-year OS and DSS rates of female vs. male patients were 74% vs. 63% (P < 0.001) and 76% vs. 64%, respectively (P < 0.001). A multivariate analysis showed that gender, age, and TNM stage were independent prognostic factors for the 5-year OS and DSS of NPC patients. The favorable prognosis of female patients is not only attributed to the early diagnosis and treatment but might also be attributed to some intrinsic factors of female patients.

关键词：鼻咽癌患者女性预后中山大学多因素分析 DSS 临床资料