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利用微波辅助萃取、电感耦合等离子体质谱和离子色谱联用方法测定生物和环境样品中的重金属以评价其对人体健康的潜在危害

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环境与职业医学 2003年第6期20卷 418-421页

作者： Brian Buckley Willie johnson eric Fischer 涂强 Mark Heintz 美国新泽西州罗格斯州立大学环境与职业健康科学研究所

[目的]测定生物和环境样品中的重金属及其化学形态,从而更准确地评价其对人体健康的潜在危害,并且监测重金属从环境基质到人体的迁移途径.[方法]利用微波辅助萃取进行样品预处理,离子色谱分离重金属不同化学形态,电感耦合等离子体质谱... 详细信息

[目的]测定生物和环境样品中的重金属及其化学形态,从而更准确地评价其对人体健康的潜在危害,并且监测重金属从环境基质到人体的迁移途径.[方法]利用微波辅助萃取进行样品预处理,离子色谱分离重金属不同化学形态,电感耦合等离子体质谱进行检测.[结果]微波辅助萃取能够将重金属的不同无机和有机形态从样品基质中有效分离,分离过程中金属形态不发生变化.将离子色谱和电感耦合等离子体质谱在线联用,辅以稳定性同位素标记,可以准确测定生物和环境样品中的金属(铅、铬和汞)形态.[结论]提高生物和环境样品中重金属检测的灵敏度,并且测定金属的化学形态,可以对评价重金属对人体健康的潜在危害提供重要信息.

关键词：微波辅助萃取电感耦合等离子体质谱离子色谱生物样品环境样品重金属危险评价

Morphology-dependent space charge polarization and dielectric relaxation of CdO nanomorphotypes

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Journal of Advanced Dielectrics 2016年第4期6卷 37-44页

作者： Paulose Thomas K.e.Abraham Department of Physics St.Berchmans College Changanassery686101KeralaIndia

A versatile approach signifying the morphology-dependent dielectric polarization and relaxation mechanisms of cadmium oxide(CdO)nanosphere,nanoflakes and nanoparallelepiped morphotypes as a function of frequency and temperature is *** of dielectric property is observed due to the changes of space charge/interfacial polarization resulting from the variations of surface to volume ratio of ***,colossal dielectric constant value has been observed in CdO nano-sphere having larger surface to volume *** order of dielectric constant(dc)values observed for the present nanomorphologies is:dc of sphere>dc of flakes>dc of parallelepiped resembles the order of surface to volume ratios of the present morphologies *** experimental data of complex impedance values are numerically fitted using theoretical models which provide the information of role of grain resistance on dielectric polarization and Cole–Cole type mechanism of dielectric relaxation *** activation energies for electron transport are found to be 0.087 eV for spheres,0.074 eV for flakes and 0.067 for parallelepiped nanomorphotypes of *** dielectric and impedance spectroscopic analysis of the present material opens up wide scope for morphology-dependent tuning of nanomaterials for electrical applications.

关键词： CdO nanomorphotype space charge polarization impedance spectroscopy Cole-Cole dielectric relaxation.

Reiterated homogenization of a laminate with imperfect contact:gain-enhancement of effective properties

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Applied Mathematics and Mechanics(english edition) 2018年第8期39卷 1119-1146页

作者： F.e.ALVAReZ-BORGeS J.BRAVO-CASTILLeRO M.e.CRUZ R.GUINOVART-DIAZ L.D.PeReZ-FeRNANDeZ R.RODRIGUeZ-RAMOS F.J.SABINA Facultad de Matematica y Computacion Departamento de MatematicaUniversidad de La HabanaSan Lazaro y LHabana 4La HabanaCP 10400Cuba Departamento de Matematicas y Mecanica Universidad Nacional Autonoma de MexicoInstituto de Investigaciones en Matematicas Aplicadas y en Sistemas01000 CDMXAP 20-126M′exico Departamento de engenharia Mecanica Universidade Federal do Rio de JaneiroPolitecnica/COPPECaixa Postal 68503Rio de JaneiroRJCEP 21941-972Brasil Departamento de Matematica e estatistica Universidade Federal de PelotasCaixa Postal 354PelotasRio Grande do SulCEP 96010-900Brasil

A family of one-dimensional(1D) elliptic boundary-value problems with periodic and rapidly-oscillating piecewise-smooth coefficients is considered. The coefficients depend on the local or fast variables corresponding to two different structural scales. A finite number of imperfect contact conditions are analyzed at each of the scales. The reiterated homogenization method(RHM) is used to construct a formal asymptotic solution. The homogenized problem, the local problems, and the corresponding effective coefficients are obtained. A variational formulation is derived to obtain an estimate to prove the proximity between the solutions of the original problem and the homogenized problem. Numerical computations are used to illustrate both the convergence of the solutions and the gain of the effective properties of a three-scale heterogeneous 1D laminate with respect to their two-scale counterparts. The theoretical and practical ideas exposed here could be used to mathematically model multidimensional problems involving multiscale composite materials with imperfect contact at the interfaces.

关键词： reiterated homogenization method(RHM) imperfect contact variational formulation effective coefficient gain

地铁运行引起的环境振动变化规律及其主要成因分析

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铁道标准设计 2024年第2期68卷 204-210页

作者：苏立勇邬玉斌滕忻利曾钦娥刘巍宋瑞祥北京城市快轨建设管理有限公司北京100028 北京市科学技术研究院城市安全与环境科学研究所北京100054 北京市市政工程设计研究总院有限公司北京100082

为分析地铁运行引起的环境振动变化特征及其主要成因,对北京某地铁沿线地表振动、隧道壁源强展开现场测试,统计全天所有列车的振动样本数据,对比分析不同车次、不同断面的振动变化规律,总结引起环境振动值离散变化的主要原因。结果表明:... 详细信息

为分析地铁运行引起的环境振动变化特征及其主要成因,对北京某地铁沿线地表振动、隧道壁源强展开现场测试,统计全天所有列车的振动样本数据,对比分析不同车次、不同断面的振动变化规律,总结引起环境振动值离散变化的主要原因。结果表明:(1)列车通过时地表测点的振级差异最大可达到14.6 dB,离散程度大,虽然所采集20趟车的振级平均值满足了标准限值要求,但仍有30%~50%的振动值超过了标准限值;(2)隧道壁源强的差异达到22.1 dB,其原因为当天所有列车中存在5辆车的车辆状态存在异常,主要表现为车轮不圆顺,引起的隧道壁最大Z振级平均值达到了90.6 dB;(3)同一列车通过不同断面时,隧道壁振级变化显著,且与车辆状态存在显著关联,当车轮存在显著不圆顺时,不同断面的隧道壁振级差变化更为显著,最大可达到10.7 dB,是“普通车辆”的2倍,表明车轮及轨道状态的变化进一步改变了轮轨耦合作用,加剧了地铁运行引起的环境振动水平;(4)对“异常车辆”的进行车轮镟修后,地表的振动水平得到了有效降低,振级均降到了70 dB以下。

关键词：地铁源强地表振动车辆状态现场实测

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仔猪产前的生长条件会影响其断奶后的生长

国外畜牧学（猪与禽） 2007年第6期27卷 17-18页

作者：黄新新 tim Lundeen

1 产前的影响因素加拿大Alberta大学的George R Foxcroft博士在PIC 2007年座谈会上说,虽然产品的质量或产量是很多生产环节的核心问题,但养猪业应＂停止追求仔猪的数量转而关注其质量＂。

关键词：生长条件产前仔猪断奶后影响因素生产环节加拿大 PIC

Advances in Multi-Terabit, Long-Haul WDM Transmission for Terrestrial Networks

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光学学报 2003年第S1期23卷 546-547页

作者： Benyuan Zhu Lynn e. Nelson OFS 791 Holmdel-Keyport Rd Holmdel NJ 07733OFS 791 Holmdel-Keyport Rd Holmdel NJ 07733

This paper reviews the recent advances in multi-terabit long-haul transmission technologies for terrestrial optical networks. The use of high performance new fibres, low-noise Raman amplification, optimised modulation... 详细信息

关键词： for on of WDM Advances in Multi-Terabit Long-Haul WDM Transmission for Terrestrial Networks in

The cardiovascular aspects of a Ménière’s disease population——A pilot study

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Journal of Otology 2019年第2期14卷 51-56页

作者： Angela Reis Rego David Dias Ana Pinto SANDra Sousa e Castro Telma Feliciano Cecília Almeida e Sousa eNT Department Centro Hospitalar e Universitário do Porto Largo do Prof.Abel Salazar

Introduction:MD is considered a rare *** adequate model that explains MD's pathophysiology is not well ***,the vascular theory of the disease has been ***:To characterize a MD population according to its cardiovascular risk and correlate it to the MD clinical ***:In this retrospective chart study the data of 31 MD patients observed between January 2017 and April 2018 in a tertiary university hospital were *** included in the study were diagnosed according to the Barany Society *** follow-ups,patients with autoimmune disease,atopy or allergy,major psychiatric disease and migraine were ***,gender,cardiovascular risk factors,audiometric and vestibular parameters,occurrence of MD attacks in the previous 6 months,vestibular medication in course and time course of MD were recorded and compared between groups(with and without cardiovascular risk factors).Results:31 patients(61.3%females)mean aged 60.3 years(±9.7)were studied.74%of the population had at least one risk factor and 51.6%of patients had attacks in the last 6 *** was a statistically significant difference in the occurrence of MD attacks in the last 6 months(p=0.014)between MD patients with and without risk *** PTA thresholds were higher and speech discrimination was lower in individuals with more cardiovascular risk ***:Treatment of MD focusing on vascular risk factors may allow a better control of symptoms and result in a decreased need for ablative procedures in this disorder.

关键词： Meniere disease Cardiovascular disease Hypertension Prognosis

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免疫应答对仔猪生产性能的重要作用

国外畜牧学（猪与禽） 2008年第4期28卷 27-29页

作者：宁海强 tim Lundeen

1日粮特殊蛋白质对仔猪生产性能的影响Jeff Carroll博士说，拥有充足免疫保护水平的动物能够表现出较高的繁殖力、较快的生长速度和较高的饲料转化率。

关键词：生产性能免疫应答仔猪饲料转化率 Jeff 免疫保护生长速度蛋白质

基于多组学数据构建低级别胶质瘤患者预后预测模型

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现代预防医学 2024年第14期51卷 2669-2674页

作者：刘毅蓉任月秦阳武舒琪赵晋芳罗天娥山西医科大学公共卫生学院卫生统计学教研室煤炭环境致病与防治教育部重点实验室

目的探讨综合聚类方法在识别低级别胶质瘤（LGG）亚型和预后预测中的应用。方法采用集合了十种聚类算法的综合聚类算法（MOVICS）对TCGA下载的LGG患者多组学数据进行整合，得到聚类亚型；通过多因素Cox回归分析LGG的预后因素。使用mRN... 详细信息

目的探讨综合聚类方法在识别低级别胶质瘤（LGG）亚型和预后预测中的应用。方法采用集合了十种聚类算法的综合聚类算法（MOVICS）对TCGA下载的LGG患者多组学数据进行整合，得到聚类亚型；通过多因素Cox回归分析LGG的预后因素。使用mRNA数据构建随机森林分类预测模型来评估分类性能，用CGGA数据集进行外部验证。结果 LGG患者经过聚类分为两型，两组生存率差异具有统计学意义（χ2=54.410,Per评分分别为0.044、0.066、0.179和0.128,两个外部验证数据集的生存差异均有统计学意义（P䥺Symbol|@@0.05）。结论综合聚类方法能够有效识别LGG亚型，其亚型是LGG患者的预后因素，并在外部数据集CGGA中得到验证，可为LGG的临床个性化治疗提供重要的理论依据。

关键词：多组学聚类低级别胶质瘤预后预测随机森林