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基于气动位移传感器的纵切车床热误差测量方法研究

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科技资讯 2024年第9期22卷 109-111,164页

作者：吴珊韩乐岳爱强咸阳职业技术学院汽车工程学院陕西咸阳712000 西安理工大学机械与精密仪器工程学院陕西西安710048

针对传统纵切车床热误差测量方法时间长,导致测量过程中的瞬态热行为影响测量结果的问题,提出了一种基于气动位移传感器的纵切车床热误差测量方法。首先,将两个气动差动变压器(Linear Variable Displacement Transducer,LVDT)式位移传... 详细信息

针对传统纵切车床热误差测量方法时间长,导致测量过程中的瞬态热行为影响测量结果的问题,提出了一种基于气动位移传感器的纵切车床热误差测量方法。首先,将两个气动差动变压器(Linear Variable Displacement Transducer,LVDT)式位移传感器安装于刀具架上;其次,利用数控程序控制测量,可以实现刀具运动空间内X和Y方向热误差的测量,测量时间缩短至5 s;最后,进行热误差测量实验。实验表明:这种方法的测量结果与激光干涉仪测量结果平均偏差小于0.5μm,验证了这种方法的可行性与有效性。这种方法测量时间短、成本低,为纵切车床热误差补偿提供了依据。

关键词：气动位移传感器纵切车床热误差误差测量

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Semiparametric Additive Intensity Model with Frailty for Recurrent Events

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Acta Mathematica Sinica,English Series 2011年第9期27卷 1831-1842页

作者： Yah Yah LIU Yuan shan wu School of Mathematics and Statistics Wuhan University Wuhan 430072 P. R. China

The seminal Cox＇s proportional intensity model with multiplicative frailty is a popular approach to analyzing the frequently encountered recurrent event data in scientific studies. In the case of violating the proportional intensity assumption, the additive intensity model is a useful alternative. Both the additive and proportional intensity models provide two principal frameworks for studying the association between the risk factors and the disease recurrences. However, methodology devel- opment on the additive intensity model with frailty is lacking, although would be valuable. In this paper, we propose an additive intensity model with additive frailty to formulate the effects of possibly time-dependent covariates on recurrent events as well as to evaluate the intra-class dependence within recurrent events which is captured by the frailty variable. The asymptotic properties for both the regression parameters and the association parameters in frailty distribution are established. Fhrthermore, we also investigate the large-sample properties of the estimator for the cumulative baseline intensity function.

关键词： Additive intensity model counting process Donsker class frailty recurrent events

On Multiple Singular Integrals along Polynomial Curves with Rough Kernels

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Acta Mathematica Sinica,English Series 2008年第2期24卷 177-184页

作者： Huo Xiong wu shan Zhi YANG School of Mathematical Sciences Xiamen University Xiamen 361005 P. R. China

This paper is devoted to the study of a class of singular integral operators defined by polynomial mappings on product domains. Some rather weak size conditions, which imply the Lp boundedness of these singular integral operators as well as the corresponding maximal truncated singular integral operators for some fixed 1〈p〈 ∞,are given.

关键词： singular integral product domain rough kernel Littlewood-Paley theory Fourier transform estimate

Ultrasonographic reference values for assessing normal radial nerve ultrasonography in the normal population

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Neural Regeneration Research 2014年第20期9卷 1844-1849页

作者： Jun Chen shan wu Jun Ren Department of Neurology Affiliated Hospital of Guiyang Medical College Lianshui County Hospital of Jiangsu Proviuce Pharmacology University of Wyoming College of Health Sciences Wyoming INBRE ProgramLaramieWYUSA

High-resolution ultrasound has been used recently to characterize median and ulnar nerves, but is seldom used to characterize radial nerves. The radial nerve is more frequently involved in en- trapment syndromes than the ulnar and median nerves. However, the reference standard for normal radial nerves has not been established. Thus, this study measured the cross-sectional areas of radial nerves of 200 healthy male or female volunteers, aged 18 to 75, using high-resolution ultrasound. The results showed that mean cross-sectional areas of radial nerves at 4 cm upon the lateral epicondyle of the humerus and mid-humerus （midpoint between the elbow crease and axilla） were 5.14± 1.24 and 5.08 ± 1.23 mm2, respectively. The age and the dominant side did not affect the results, but the above-mentioned cross-sectional areas were larger in males （5.31± 1.25 and 5.19 ±1.23 mm2） than in females （4.93 ± 1.21 and 4.93 ± 1.23 mm2, respectively）. In addition, the cross-sectional areas of radial nerves were positively correlated with height and weight （r = 0.38, 0.36, respectively, both P 〈 0.05）. These data provide basic clinical data for the use of high-resolution ultrasound for the future diagnosis, treatment, and prognostic evalua- tion of peripheral neuropathies.

关键词： nerve regeneration high-resolution ultrasound radial nerve cross-sectional area peripheral nerve nerve lesion neural regeneration

Improving the Quality of the Deteriorated Regions of Multicrystalline Silicon Ingots during General Solar Cell Processes

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Chinese Physics Letters 2011年第4期28卷 163-166页

作者： wu shan-shan WANG Lei YANG De-Ren State Key Laboratory of Silicon Materials and the Department of Materials Science and Engineering Zhejiang UniversityHangzhou 310027

The behavior of wafers and solar cells from the border of a multicrystalline silicon(mc-Si)ingot,which contain deteriorated regions,is *** is found that the diffusion length distribution of minority carriers in the cells is uniform,and high efficiency of the solar cells(about 16%)is *** is considered that the quality of the deteriorated regions could be improved to be similar to that of adjacent ***,it is indicated that during general solar cell fabrication,phosphorus gettering and hydrogen passivation could significantly improve the quality of deteriorated regions,while aluminum gettering by RTP could ***,it is suggested that the border of a me-Si ingot could be used to fabricate high efficiency solar cells,which will increase me-Si utilization effectively.

关键词： crystalline RTP Solar

Second organic aerosol formation from the ozonolysis of α-pinene in the presence of dry submicron ammonium sulfate aerosol

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Journal of Environmental Sciences 2008年第10期20卷 1183-1188页

作者： ZHAO Zhe HAO Jiming LI Junhua wu shan Department of Environmental Science and Engineering Tsinghua University Beijing l00084 China

An indoor chamber facility is described for investigation of atmospheric aerosol chemistry. Two sets of α-pinene ozonolysis experiments were conducted in the presence of dry ammonium sulfate seed particle: ozone limited experiments and α-pinene limited experiments. The concentration of gas phase and particle phase species was monitored continuously by on-line instruments and recorded automatically by data sampling system. The evolution of size distribution was measured by a scanning mobility particle sizer ...

关键词： α-pinene ozonolysis secondary organic aerosol (SOA) chamber experiment seed particles

Amplitude Compensation for One-Way Wave Propagators in Inhomogeneous Media and its Application to Seismic Imaging

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Communications in Computational Physics 2008年第1期3卷 203-221页

作者： Jun Cao Ru-shan wu Department of Earth and Planetary Sciences University of CaliforniaSanta CruzCA 95064USA CSIDE Institute of Geophysics and Planetary PhysicsUniversity of CaliforniaSanta CruzCA 95064USA.

TheWKBJ solution for the one-waywave equations inmediawith smoothly varying velocity variation with depth,c(z),is reformulated from the principle of energy flux conservation for acoustic *** formulation is then extended to general heterogeneous media with local angle domain methods by introducing the concepts of Transparent Boundary Condition(TBC)and Transparent Propagator(TP).The influence of the WKBJ correction on image amplitudes in seismic imaging,such as depth migration in exploration seismology,is investigated in both smoothly varying c(z)and general heterogeneous *** also compare the effect of the propagator amplitude compensation with the effect of the acquisition aperture correction on the image *** results in a smoothly varying c(z)medium demonstrate that theWKBJ correction significantly improves the one-way wave propagator amplitudes,which,after compensation,agree very well with those from the full wave equation *** for a point scatterer in a smoothly varying c(z)medium show that the WKBJ correction has some improvement on the image amplitude,though it is not very *** results in a general heterogeneous medium(2D SEG/EAGE salt model)show similar *** the acquisition aperture correction is applied,the image improves significantly in both the smoothly varying c(z)medium and the 2D SEG/EAGE *** comparisons indicate that although theWKBJ compensation for propagator amplitude may be important for forward modeling(especially for wide-angle waves),its effect on the image amplitude in seismic imaging is much less noticeable compared with the acquisition aperture correction for migration with limited acquisition aperture in general heterogeneous media.

关键词： Propagator amplitude image amplitude WKBJ beamlet local angle domain seismic imaging

Multi-Frequency Contrast Source Inversion for Reflection Seismic Data

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Communications in Computational Physics 2020年第6期28卷 207-227页

作者： Shoudong Wang Ru-shan wu State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing 102249P.R.China National Engineering Laboratory of Offshore Oil Exploration China University of Petroleum(Beijing)Beijing 102249P.R.China Modeling and Imaging Laboratory Earth and Planetary SciencesUniversity of CaliforniaSanta CruzCA 95064USA

In the contrast source inversion(CSI)method,the contrast sources(equiva-lent scattering sources)and the contrast(parameter perturbation)are iteratively recon-structed by an alternating optimization *** integral equation CSI method is formulated for transmission tomography using analytic Green’s function in homogeneous *** extend the method to the case of reflection seismology,in this paper,we use WKBJ method to compute the Green’s function of depth dependent background media and the solving method of equations to initialize the contrast source of different frequencies,resulting in an efficient method to invert multi-frequency reflection seismic data–multi-frequency contrast source inversion method(MFCSI).Numerical results for the Marmousi model show that MFCSI method can obtain good results even when low frequency data are missing,in which case the conventional FWI fails.

关键词： Contrast source inversion full waveform inversion frequency domain inversion integral equation CSI

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苯炔的制备和反应实验的改进与再设计

化学教育（中英文） 2024年第8期45卷 43-47页

作者：文巍吴杉石佳乔恪凡郭其祥吴竹莲西南大学化学化工学院重庆400715

苯炔的制备和反应实验同时融合了苯炔和Diels-Alder反应相关知识,是大学有机化学实验教学的重要内容之一。传统的实验方案以邻氨基苯甲酸为原料首先制得取代芳基重氮盐,通过重氮盐的热分解产生苯炔,然后与蒽发生Diels-Alder反应。但邻... 详细信息

苯炔的制备和反应实验同时融合了苯炔和Diels-Alder反应相关知识,是大学有机化学实验教学的重要内容之一。传统的实验方案以邻氨基苯甲酸为原料首先制得取代芳基重氮盐,通过重氮盐的热分解产生苯炔,然后与蒽发生Diels-Alder反应。但邻氨基苯甲酸属于第一类易制毒化学品,为本实验的开展带来不便。同时传统方案还存在诸多不足,如存在潜在的爆炸风险,需要使用到危化品试剂,产品纯化难度大且操作繁琐等。本改进方案通过改变苯炔前体和苯炔捕获试剂克服了原有方案的不足,并且实验原料易得、时长合适、条件温和、反应重复性好,适合本科有机化学实验教学。更为重要的是,通过设计对照实验引入探索性讨论学习内容,有利于学生综合能力的提升和科学思维的培养。

关键词：苯炔 Diels-Alder反应呋喃实验改进