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Research on temperature field of non-uniform heat source model in surface grinding by cup wheel

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Advances in Manufacturing 2019年第3期7卷 326-342页

作者： Shi-jie dai Xiao-Qiang Li Hui-Bo Zhang State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of TechnologyTianjin 300130People's Republic of China School of Mechanical Engineering Hebei University of TechnologyTianjin 300130People's Republic of China Hebei Key Laboratory of Robot Perception and Human-Robot Interaction Tianjin 300130People's Republic of China

To address the problems of thermal damage to a workpiece surface caused by the instantaneous high temperature during grinding and the difficulty in monitoring temperature in real time,the temperature field in the case of composite surface grinding by a cup wheel is *** order to predict the grinding temperature,considering material removal and grinding force distribution,a nonuniform heat source model with different function distributions in the circumferential and radial directions in the cylindrical coordinate system is first proposed;then,the analytical model is deduced and the numerical model of the temperature field is established based on the heat source *** validation experiments for grinding temperature field are carried out using a high-definition infrared thermal imager and an artificial *** to the temperature field based on the uniform heat source model,the results based on the non-uniform heat source model are in better agreement with the actual temperature field,and the temperature prediction error is reduced from approximately 23% to 6%.Thus,the present study provides a more accurate theoretical basis for preventing bums in cup wheel surface grinding.

关键词： Non-uniform heat source Temperature filed Surface grinding Cup wheel

基于土壤重金属污染和累积性评价的耕地环境质量类别划分与风险管控

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生态环境学报 2025年第2期34卷 311-320页

作者：张传华刘力代杰李曼曼张凤太邓凌重庆理工大学管理学院重庆400054 中国农工民主党重庆市江津区工作委员会重庆402218 重庆社会主义学院重庆400064

以重庆彭水县大同镇为例,协同采集土壤-玉米样品50套,分析土壤及玉米样品中Cd、Hg、As、Pb和Cr的含量及土壤pH,综合考虑土壤重金属污染及累积性,开展耕地土壤环境质量类别划分,提出风险管控措施建议,以期为地质高背景区耕地土壤风险管... 详细信息

以重庆彭水县大同镇为例,协同采集土壤-玉米样品50套,分析土壤及玉米样品中Cd、Hg、As、Pb和Cr的含量及土壤pH,综合考虑土壤重金属污染及累积性,开展耕地土壤环境质量类别划分,提出风险管控措施建议,以期为地质高背景区耕地土壤风险管控提供技术方法。结果表明,研究区耕地土壤以安全利用类和严格管控类为主,土壤存在明显重金属累积的点位占比为22%,主要的超标及累积因子为Cd和As,土壤重金属污染及累积问题显著。研究区耕地土壤环境质量类别以III类(安全利用类,无明显累积)为主,IV类(安全利用类,有明显累积)和VI类(严格管控类,无明显累积)耕地均分布在研究区西南部。研究区耕地土壤重金属超标整体受地质背景的影响,重金属累积主要与城镇生活污水、禽畜粪肥和部分复合肥施用等人为活动有关,由于外源输入,部分耕地土壤超标程度加剧趋势明显。研究区玉米样品的总体超标率为28%,超标因子为Cd。当土壤pH>6.5时,农产品超标风险显著降低。建议在耕地土壤重金属溯源断源的基础上,根据土壤及农产品污染程度,施用钙质土壤调理剂或钙镁磷肥进行土壤酸化治理,实现“边生产,边修复”,逐渐改善研究区土壤环境质量状况。

关键词：耕地重金属污染累积性评价环境质量类别划分

CDH1 promoter polymorphism(-347G→GA) is a possible prognostic factor in sporadic colorectal cancer

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World Journal of Gastroenterology 2009年第42期15卷 5340-5345页

作者： Xiao-Ping Zou Wei-jie dai Jun Cao Department of Gastroenterology The Affiliated Drum Tower Hospital of Nanjing University Medical School Nanjing 210008 Jiangsu Province China Department of Internal Medicine Clinical Medical Colleges of Drum Tower Nanjing Medical University Nanjing 210029 Jiangsu Province China

AIM:To investigate the role of the-347G→GA polymorphism in the progression of colorectal cancer(CRC) .METHODS:We designed a case-control study based on a population of CRC patients in China and normal healthy controls with no history of tumors or inherited *** chain reaction-restriction fragment length polymorphism(PCR-RFLP) analyses were used to genotype the variants,and immunohistochemical staining was performed to measure the expression of E-cadherin in different allele cases among the CRC patients and normal ***:The GA-allele(G/GA heterozygous and GA/GA homozygous) did not increase the risk of CRC compared with the G-allele(OR = 1.232,95% CI = 0.898-1.691) .However,the frequencies of the GAallele were higher in poorly differentiated(P = 0.002) and proximal(P = 0.019) CRC patients than in normal *** also observed that E-cadherin expression was lower in poorly differentiated CRC patients than in well differentiated CRC patients(P = 0.001) .Furthermore,E-cadherin expression was lower for the GA-allele than for the G-allele(G/G heterozygous) in CRC patients(P = 0.018) .In contrast,there was no significant difference in E-cadherin expression for the G-allele and GA-allele in normal controls(P = 0.292) .CONCLUSION:The-347G→GA promoter polymorphism in E-cadherin gene is associated with specific CRC features,and may be a prognostic factor rather than a susceptibility factor during the progression of CRC.

关键词： Allele Colorectal cancer E-cadherin Polymorphism Prognosis

Thermal Characterization and Decomposition Kinetics of Free Anthraquinones from Rhubarb

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Chinese Chemical Letters 2006年第5期17卷 699-702页

作者： Li Ming ZHANG Xia LI Yu jie dai College of Bioengineering Tianjin University of Science ＆ Technology Tianjin 300222

The thermal behaviour of aloe-emodin, chrysophanol and physcion and their kinetics have been investigated under non-isothermal conditions by means of differential thermal analysis （DTA） and thermogravimetry （TG）. The thermal characteristics have been determined using the DTA and TG-DTG curves. The non-isothermal kinetic data were analyzed by means of the Achar method and the Madhusudanan-Krishnan-Ninan （MKN） method. The possible reaction mechanisms have been investigated by comparing the kinetic parameters. The kinetic equation for aloe-emodin, chrysophanol and physcion can be expressed as dα/dt=Aexp（-E/RT）1/3（1-α）[-In（1-α]2. The activation energy E （kJ mol^-1） of the three free anthraquinones are 78.09, 89.54, and 107.5 and their InA/s^-1 are 22.98, 36.85 and 43.60, respectively.

关键词： Aloe-emodin chrysophanol physcion thermogravimetry (TG) differential thermoanalysis (DTA) non-isothermal kinetics.

Scheme to Implement Optimal Asymmetric Economical Phase-Covariant Quantum Cloning in Cavity QED

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Communications in Theoretical Physics 2008年第6期49卷 1473-1476页

作者： ZHANG Wen-Hai dai jie-Lin YE Liu School of Physics and Material Science Anhui University Hefei 230039 China Department of Physics ＆ Electronic Engineering Hefei Teachers College Hefei 230061 Chine

We propose an experimentally feasible scheme to implement the optimal asymmetric economical 1→2 phase-covariant quantum cloning in two dimensions based on the cavity QED technique. The protocol is very simple and only two atoms are required. Our scheme is insensitive to the cavity field states and cavity decay. During the processes, the cavity is only virtually excited and it thus greatly prolongs the efficient decoherent time. Therefore, it may be realized in experiment.

关键词： optimal asymmetric economical phase-covariant cloning cavity QED

ESL-SELO:A Robust Image Denoising Algorithm with Penalty

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Acta Mathematicae Applicatae Sinica 2017年第3期33卷 753-770页

作者： Guo-hua WANG San-guo ZHANG Peng-jie dai School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Big Data Mining and Knowledge Management Chinese Academy of SciencesBeijing100049China School of Business Remin University of ChinaBeijing 100872China

Robust image recovery methods have been attracted more and more attention in recent decades for its good property of tolerating system errors or measuring noise. In this paper, we propose a new robust method （ESL-SELO） to recover nosing image, which combine exponential loss function and seamless-L0 （SELO） penalty function to guarantee both accuracy and robustness of the estimator. Theoretical result showed that our method has a local optimal solution and good asymptotic properties. Finally, we compare our method with other methods in simulation which shows better robustness and takes much less time.

关键词： denoising algorithm penalty function robust SELO

Variable Selection of Generalized Regression Models Based on Maximum Rank Correlation

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Acta Mathematicae Applicatae Sinica 2014年第3期30卷 833-844页

作者： Peng-jie dai Qing-zhao ZHANG Zhi-hua SUN School of Business Renmin University of China Department of Mathematics University of Chinese Academy of Sciences

In this paper, we investigate the variable selection problem of the generalized regression models. To estimate the regression parameter, a procedure combining the rank correlation method and the adaptive lasso technique is developed, which is proved to have oracle properties. A modified IMO （iterative marginal optimization） algorithm which directly aims to maximize the penalized rank correlation function is proposed. The effects of the estimating procedure are illustrated by simulation studies.

关键词： maximum rank correlation estimation adaptive LASSO oracle properties generalized regression models.

Identification of candidate millisecond pulsars from Fermi LAT observations Ⅱ

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Research in Astronomy and Astrophysics 2017年第7期17卷 89-98页

作者： Xue-jie dai Zhong-Xiang Wang Jithesh Vadakkumthani Yi Xing Shanghai Astronomical Observatory Chinese Academy of Sciences University of Chinese Academy of Sciences

On the basis of the properties of known γ-ray millisecond pulsars（MSPs）, we have selected 77un-associated sources from the Fermi Large Area Telescope（LAT） third source catalog for the purpose of finding likely candidate MSPs. Previously, detailed LAT data analysis for 39 of them was reported,and here we report the analysis for the remaining 38 sources. We identify that among the 38 sources, 28 of them are single point-like sources with clean background and their spectra show significant *** also conduct an analysis of archival X-ray data available for 24 of the 28 sources. In the fields of10 sources, there is at least one X-ray object, and in those of the other 14 sources, no X-ray object is detected but this is probably due to the X-ray observations being short. We discuss the possible MSP nature for these sources. Six of them（J0514.6-4406, J1035.7-6720, J1624.2-4041, J1744.1-7619,J1946.4-5403 and J2039.6-5618） are most likely associated with pulsars because of multi-wavelength identifications including direct radio or γ-ray detection of pulsations. To firmly establish the associations or verify the MSP nature for other sources, deep X-ray and/or optical observations are needed.

关键词： stars pulsars - stars binaries - gamma rays stars

Identification of candidate millisecond pulsars from Fermi LAT observations

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Research in Astronomy and Astrophysics 2016年第6期16卷 113-122页

作者： Xue-jie dai Zhong-Xiang Wang Jithesh Vadakkumthani Yi Xing Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China University of Chinese Academy of Sciences Beijing 100049China

We report our detailed data analysis of 39 γ-ray sources selected from the 992 unassociated sources in the third Fermi Large Area Telescope Third Source Catalog. The selection criteria, which were set for finding candidate millisecond pulsars （MSPs）, are non-variables with curved spectra and 〉5° Galactic latitudes. From our analysis, 24 sources were found to be point-like sources not contaminated by back- ground or nearby unknown sources. Three of them, Jl544.6-1125, J1625.1-0021 and J1653.6-0158, have been previously studied, indicating that they are likely MSPs. The spectra of J0318.1＋0252 and J2053.9＋2922 do not have properties similar to known γ-ray MSPs, and we thus suggest that they are not MSPs. Analysis of archival X-ray data for most of the 24 sources was also conducted. Four sources were found with X-ray objects in their error circles, and 16 with no detection. The ratios between the γ-ray fluxes and X-ray fluxes or flux upper limits are generally lower than those of known γ-ray MSPs, suggesting that if the γ-ray sources are MSPs, none of the X-ray objects are their counterparts. Deep X-ray or radio observations of these sources are needed in order to identify their MSP nature.

关键词： stars pulsars -- stars binaries -- gamma rays stars