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Sectoral changes of the peripapillary choroidal thickness in patients with unilateral branch retinal vein occlusion
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作者 Na Eun Lee Hae Min Kang +2 位作者 Jeong Hoon Choi Hyoung Jun Koh Sung Chul Lee 《国际眼科杂志:英文版》 SCIE CAS 2019年第3期472-479,共8页
AIM: To investigate sectoral changes in the mean peripapillary choroidal thickness(PCT) in patients with unilateral branch retinal vein occlusion(BRVO). METHODS: This retrospective, interventional study included 41 pa... AIM: To investigate sectoral changes in the mean peripapillary choroidal thickness(PCT) in patients with unilateral branch retinal vein occlusion(BRVO). METHODS: This retrospective, interventional study included 41 patients with acute, unilateral BRVO without macular edema. All patients completed at least a 6-month follow-up period. The PCT was measured at eight locations(temporal, superotemporal, superior, superonasal, nasal, inferonasal, inferior, and inferotemporal). In addition to calculating the average of all locations, the peripapillary choroidal area was divided into four sectors: superior(average of superotemporal PCT, superior PCT, and superonasal PCT), temporal, inferior(average of inferotemporal PCT, inferior PCT, and inferonasal PCT), and nasal. RESULTS: In the BRVO-affected eyes, the mean PCT was 177.7±69.8 μm(range, 70.1-396.0 μm) at baseline and 127.8±54.8 μm(range, 56.4-312.1 μm) at 6 mo(P<0.001). In the non-affected contralateral eyes, the mean PCT was 192.5±60.6 μm(range, 61.4-365.0 μm) at baseline and 165.9±61.1 μm(range, 56.8-326.8 μm) at 6 mo(P<0.001). In sectoral analysis, the mean PCT in each sector was significantly reduced in over 6 mo in the BRVO-affected eyes(all P<0.001). In the non-affected contralateral eyes, the mean PCT was not significantly changed in any sector over the 6-month follow-up period(superior sector, P=0.143;temporal sector, P=0.825;inferior sector, P=0.192;and nasal sector, P=0.599).CONCLUSION: Sectoral analysis shows that the mean PCTs in all sectors are reduced significantly over 6 mo in the BRVO-affected eyes, but not in the non-affected contralateral eyes. 展开更多
关键词 branch RETINAL VEIN OCCLUSION CHOROID choroidal thickness peripapillary choroidal thickness
提高MEMS用超薄硅片厚度测量质量的研究 预览
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作者 王世援 《电子工业专用设备》 2019年第1期41-44,共4页
从常用MEMS器件用硅片对厚度测试要求的角度出发,分析了厚度测试设备-晶片厚度测试系统在测试MEMS用超薄高精度硅片时引发测量不确定度的主要来源,并对各来源引起的不确定度分量大小进行了计算。结果表明,测试用的校准厚度样片是影响整... 从常用MEMS器件用硅片对厚度测试要求的角度出发,分析了厚度测试设备-晶片厚度测试系统在测试MEMS用超薄高精度硅片时引发测量不确定度的主要来源,并对各来源引起的不确定度分量大小进行了计算。结果表明,测试用的校准厚度样片是影响整个测试系统不确定度的主要因素。重点研究了校准样片的几何参数(主要指局部厚度变化DLTV)与其本身不确定度的关系。研究发现,降低校准样片的DLTV值能够有效降低其不确定度大小,当DLTV值为0.46μm时,校准样片的扩展不确定度值为0.3μm,整个测试系统的扩展不确定度值为0.5μm,能够较好地提升测试质量、保证硅片初始厚度的一致性。 展开更多
关键词 校准样片 厚度 不确定度 局部厚度变化
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Comparison of peripapillary and macular choroidal thickness and ganglion cell complex thickness in glaucomatous and healthy eyes
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作者 Yuli Park Hong Kyu Kim Kyong Jin Cho 《国际眼科杂志:英文版》 SCIE CAS 2019年第4期603-606,共4页
AIM: To assess choroidal thickness (CT) and its association with ganglion cell-inner plexiform layer thickness (GCIPLT) and retinal nerve fiber layer thickness (RNFLT) in open angle glaucoma (OAG) comparing with prepe... AIM: To assess choroidal thickness (CT) and its association with ganglion cell-inner plexiform layer thickness (GCIPLT) and retinal nerve fiber layer thickness (RNFLT) in open angle glaucoma (OAG) comparing with preperimetric glaucoma (PPG) and normal eyes. METHODS: Totally 55 eyes of OAG, 40 eyes of PPG, and 40 eyes of age-matched normal eyes were studied. Peripapillary CT (PCT), macular CT (MCT), RNFLT, and GCIPLT were evaluated. Relationship between the CT with RNFLT and GCIPLT were studied. The correlation between CT and confounding variables as gender, age, intraocular pressure, and visual field mean deviation were analyzed. RESULTS: Mean PCT were 113.6±39.1 μm in OAG, 116.3±42.7 μm in PPG, and 148.9±41.7 μm in normal eyes. PCT and MCT was thinner in OAG compared to healthy eyes. There was a significant correlation for PCT and mean RNFLT in 1, 2, 6, and 7 clock hours of OAG eyes. The difference in PCT remained after adjusting for axial length, age, and disc area (P=0.003). No significant correlation was shown between MCT and mean GCIPLT in all eyes. CONCLUSION: PCT is thinner in OAG and PPG compared with healthy eyes. The correlation of RNFLT and PCT found in OAG and PPG is not revealed in normal eyes. 展开更多
关键词 choroidal thickness GANGLION cell complex optical COHERENCE tomography GLAUCOMA
敏感电极层厚度对二氧化碳传感器性能的影响
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作者 王光伟 陈鸿珍 +2 位作者 李友凤 谢波 梁兴 《功能材料与器件学报》 CAS 2019年第1期12-18,共7页
利用碳酸锂-锂钡掺杂氧化碳酸盐复合物作为敏感电极材料,构建YSZ二氧化碳电化学传感器,并借助于二氧化碳响应性能测试和电化学阻抗谱等方法,研究了敏感电极层厚度对传感器性能的影响。结果表明,敏感电极层较薄时,由于电极过程涉及的电... 利用碳酸锂-锂钡掺杂氧化碳酸盐复合物作为敏感电极材料,构建YSZ二氧化碳电化学传感器,并借助于二氧化碳响应性能测试和电化学阻抗谱等方法,研究了敏感电极层厚度对传感器性能的影响。结果表明,敏感电极层较薄时,由于电极过程涉及的电活性物质的量较大,而其产生和运移的场所却有限,可能导致局部二氧化碳浓度范围出现传感器响应电动势的波动;敏感电极层厚度增加时,传感器总阻抗增加,其响应电动势比例以及电动势变化率△E均降低,电子转移数偏离理论值2,传感器准确性降低。具体设计过程中,传感器敏感电极层厚度应适中,并结合其工作温度综合考虑。 展开更多
关键词 敏感电极 厚度 CO2传感器 响应 阻抗
核瓷和饰瓷厚度变化对全瓷修复体抗弯强度影响的研究进展 预览
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作者 靳志亨 李清 《国际口腔医学杂志》 CAS CSCD 2019年第1期94-98,共5页
随着人们对口腔美学要求的不断提高,全瓷修复成为当前口腔固定修复的主要趋势。但是,由核瓷与饰面瓷构成的全瓷修复体的力学强度仍是人们关注的问题之一。因此,如何更好地设计全瓷修复体以应对口腔较为复杂的咬合力将显得格外重要,尤其... 随着人们对口腔美学要求的不断提高,全瓷修复成为当前口腔固定修复的主要趋势。但是,由核瓷与饰面瓷构成的全瓷修复体的力学强度仍是人们关注的问题之一。因此,如何更好地设计全瓷修复体以应对口腔较为复杂的咬合力将显得格外重要,尤其是核瓷与饰面瓷厚度改变时,修复体抗弯强度将如何变化依旧没有定论。目前,已有不少关于这方面的研究,但各研究之间的实验设计、背景、方法等并不相同,本文将对这些差异性因素进行介绍与分析。 展开更多
关键词 核瓷 饰面瓷 厚度 抗弯强度
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织物规格与热传导性能的关系研究 预览
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作者 张莹 马新安 +1 位作者 张生辉 马建超 《棉纺织技术》 CAS 北大核心 2019年第1期39-41,共3页
探讨织物规格对织物热传导性能的影响。测试分析了织物热传导性能与其单位面积质量、紧度、厚度、经纬密、织物组织以及织物材料之间的关系。结果表明:织物的单位面积质量和厚度是影响织物热传导性能的主要因素,而紧度、织物组织等对织... 探讨织物规格对织物热传导性能的影响。测试分析了织物热传导性能与其单位面积质量、紧度、厚度、经纬密、织物组织以及织物材料之间的关系。结果表明:织物的单位面积质量和厚度是影响织物热传导性能的主要因素,而紧度、织物组织等对织物的热传导性能影响较小。认为:深入了解影响织物热传导性能的因素,有助于企业设计和生产相关产品。 展开更多
关键词 热传导性能 织物组织 单位面积质量 厚度 经纬密 织物紧度
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Preparation and Corrosion Resistance of Anodic Oxidation Coatings on 2198 and 5A90 Al-Li Alloys
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作者 王赫男 LI Xinming +2 位作者 HE Linbo CUI Baolei LIU Chunzhong 《武汉理工大学学报:材料科学英文版》 SCIE EI CAS 2019年第1期132-137,共6页
2198 and 5A90 Al-Li alloys were anodized with a constant DC potential in 18%H2SO4solution(Solu.A) and the mixture solution of 18%H2SO4+5%C2H2O4(Solu.B) at room temperature. 12 and 11 V was optimized as the applied oxi... 2198 and 5A90 Al-Li alloys were anodized with a constant DC potential in 18%H2SO4solution(Solu.A) and the mixture solution of 18%H2SO4+5%C2H2O4(Solu.B) at room temperature. 12 and 11 V was optimized as the applied oxidation potential for 2198 and 5A90 alloys, respectively. Cross-sectional morphology, surface morphology and elements distribution of anodic oxidation coatings were observed by scanning electron microscope equipped with energy dispersive X-ray analysis(SEM/EDX). Corrosion resistance was tested by potentiodynamic polarization plot in 3.5%NaCl solution. The results showed that the thicknesses of coatings obtained at the selected potential in Solu.A and Solu.B were about 50 μm/110 μm for 2198 alloy and 80 μm/110 μm for 5A90 alloy. In both solutions, anodic oxidation coatings of 2198 alloy were primarily composed of Al oxides;those of 5A90 alloy were mainly consisted of Al oxides and a small amount of Mg oxides. The results of potentiodynamic polarization showed that anodic oxidation coatings of 2198 and 5A90 Al-Li alloys had better corrosion resistances than that of untreated alloys. 展开更多
关键词 AL-LI alloy the MIXTURE solution anodic OXIDATION COATING corrosion resistance thickness
Spatial and temporal evolution of landfast ice near Zhongshan Station,East Antarctica,over an annual cycle in 2011/2012 预览
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作者 Jiechen Zhao Qinghua Yang +8 位作者 Bin Cheng Matti Lepparanta Fengming Hui Surui Xie Meng Chen Yining Yu Zhongxiang Tian Ming Li Lin Zhang 《海洋学报:英文版》 SCIE CAS CSCD 2019年第5期51-61,共11页
Annual observations of first-year ice(FYI)and second-year ice(SYI)near Zhongshan Station,East Antarctica,were conducted for the first time from December 2011 to December 2012.Melt ponds appeared from early December 20... Annual observations of first-year ice(FYI)and second-year ice(SYI)near Zhongshan Station,East Antarctica,were conducted for the first time from December 2011 to December 2012.Melt ponds appeared from early December 2011.Landfast ice partly broke in late January,2012 after a strong cyclone.Open water was refrozen to form new ice cover in mid-February,and then FYI and SYI co-existed in March with a growth rate of 0.8 cm/d for FYI and a melting rate of 2.7 cm/d for SYI.This difference was due to the oceanic heat flux and the thickness of ice,with weaker heat flux through thicker ice.From May onward,FYI and SYI showed a similar growth by 0.5 cm/d.Their maximum thickness reached 160.5 cm and 167.0 cm,respectively,in late October.Drillings showed variations of FYI thickness to be generally less than 1.0 cm,but variations were up to 33.0 cm for SYI in March,suggesting that the SYI bottom was particularly uneven.Snow distribution was strongly affected by wind and surface roughness,leading to large thickness differences in the different sites.Snow and ice thickness in Nella Fjord had a similar“east thicker,west thinner”spatial distribution.Easterly prevailing wind and local topography led to this snow pattern.Superimposed ice induced by snow cover melting in summer thickened multi-year ice,causing it to be thicker than the snow-free SYI.The estimated monthly oceanic heat flux was~30.0 W/m2 in March–May,reducing to~10.0 W/m2 during July–October,and increasing to~15.0 W/m2 in November.The seasonal change and mean value of 15.6 W/m2 was similar to the findings of previous research.The results can be used to further our understanding of landfast ice for climate change study and Chinese Antarctic Expedition services. 展开更多
关键词 landfast ice thickness OCEANIC heat flux PRYDZ BAY East ANTARCTICA
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基于平行板电容器的材料表面形貌测量仪 预览
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作者 白雪琪 廖琨 +2 位作者 唐际杰 张谷令 邹斌 《物理实验》 2019年第2期32-36,共5页
利用平行板电容器的原理设计了材料表面形貌测量仪,将探针与电容器下极板固连,当探针在不平整的样品表面扫描时,两极板间距发生改变而引起电容变化.通过LabVIEW编程控制平移台蛇形移动,用平行板电容器厚度测试电路测量pF量级的电容改变... 利用平行板电容器的原理设计了材料表面形貌测量仪,将探针与电容器下极板固连,当探针在不平整的样品表面扫描时,两极板间距发生改变而引起电容变化.通过LabVIEW编程控制平移台蛇形移动,用平行板电容器厚度测试电路测量pF量级的电容改变值.两极板初始距离为50~200μm的工作范围内,测量误差稳定在2μm.通过实时捕捉探针的坐标和极板间距的变化量,该测量仪可以绘制出三维曲面图. 展开更多
关键词 平行板电容器 表面形貌 厚度
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电镀镍过程智能控制方法的探讨 预览
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作者 王思醇 岑廷刺 +2 位作者 罗毅 田军 宋泽洪 《电镀与涂饰》 CAS CSCD 北大核心 2019年第1期9-13,共5页
为保证电镀镍层厚度的均匀性和内应力在一定范围内,考察了各种工艺参数对镀层厚度和内应力的影响,确定了镀液中镍离子质量浓度、阴极电流密度和电镀时间是关键因素,并建立了它们之间的数学关系。根据镀液中的镍离子质量浓度来调整阴极... 为保证电镀镍层厚度的均匀性和内应力在一定范围内,考察了各种工艺参数对镀层厚度和内应力的影响,确定了镀液中镍离子质量浓度、阴极电流密度和电镀时间是关键因素,并建立了它们之间的数学关系。根据镀液中的镍离子质量浓度来调整阴极电流密度,继而改变电镀时间。该智能控制方法在批量生产中被证明是可行的,可确保镀层质量稳定、一致。 展开更多
关键词 电镀镍 厚度 内应力 工艺参数 智能控制
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Primary investigation of statistical correlation between changes in ice volume and area of glaciers 预览
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作者 PuYu Wang ZhongQin Li +4 位作者 ChunHai Xu Ping Zhou WenBin Wang Shuang Jin HongLiang Li 《寒旱区科学:英文版》 CSCD 2019年第1期41-49,共9页
This study makes an attempt to investigate through statistical analysis the correlation between changes in ice volume and area of glaciers.Using data from nine sample glaciers in the Tian Shan,the results show that a ... This study makes an attempt to investigate through statistical analysis the correlation between changes in ice volume and area of glaciers.Using data from nine sample glaciers in the Tian Shan,the results show that a linear relation exists between changes in ice volume and area,with a correlation coefficient of 0.700.However,the accuracy estimation is difficult due to the limited number of samples.The correlation was not improved after adding eleven glacier samples in other mountains.Two reference glaciers are then analyzed in more detail.The linear correlation coefficient is higher than 0.800 when using the observed changes in ice volume and area during different periods on Urumqi Glacier No.1,which suggests that the linear relation is valid for one glacier for different periods if its shape does not change noticeably and also for other glaciers of the same shape during the same period.The relation between changes in ice volume and area of Qingbingtan Glacier No.72 is different during different periods due to change in the shape of the glacier tongue and the influence of the debris cover.Moreover,errors in glacier-change monitoring and-volume estimation have an important influence on the correlation results.Therefore,further study needs to focus not only on the distinction between glacier types and between different periods but also on the accuracy of volume estimation. 展开更多
关键词 VOLUME CHANGE area CHANGE thickness STATISTICAL CORRELATION glaciers
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电解铜箔用涂层钛阳极的结垢物成因分析与维护方法 预览
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作者 焦新贺 焦衡 +2 位作者 徐海清 赵国鹏 陈姚 《电镀与涂饰》 CAS CSCD 北大核心 2019年第1期14-19,共6页
分析了电解铜箔用涂层钛阳极板失效的主要原因。以阳极螺钉为代表,采用扫描电镜观察了阳极失效前后的表面形貌,并用能谱仪和X射线衍射仪测得阳极表面结垢物(俗称阳极泥)的主要成分是铅的氧化物和硫酸铅。阳极泥的不均匀沉积会造成阳极... 分析了电解铜箔用涂层钛阳极板失效的主要原因。以阳极螺钉为代表,采用扫描电镜观察了阳极失效前后的表面形貌,并用能谱仪和X射线衍射仪测得阳极表面结垢物(俗称阳极泥)的主要成分是铅的氧化物和硫酸铅。阳极泥的不均匀沉积会造成阳极不同部位上析氧电位存在差异,从而影响铜箔厚度的均匀性和质量。根据经验给出了延长阳极使用寿命的方法。 展开更多
关键词 电解铜箔 厚度 涂层钛阳极 结垢
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根据撕裂口纤维束特征鉴别猪、牛、山羊革
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作者 李晓龙 张莉 +2 位作者 罗媛媛 罗娟 胡阳 《皮革科学与工程》 CAS 北大核心 2019年第4期50-53,57共5页
将猪、牛、山羊革沿剪口撕裂,裂口产生许多胶原蛋白纤维束,在显微镜下放大测量纤维束的长度、粗细程度以及观察胶原纤维分散程度等显微特征,通过纤维束长度、粗细程度、分散程度等数据,与标准皮革样品图库数据进行比对,完成猪、牛、山... 将猪、牛、山羊革沿剪口撕裂,裂口产生许多胶原蛋白纤维束,在显微镜下放大测量纤维束的长度、粗细程度以及观察胶原纤维分散程度等显微特征,通过纤维束长度、粗细程度、分散程度等数据,与标准皮革样品图库数据进行比对,完成猪、牛、山羊革材质鉴别。结果表面,纤维束长4~10mm,粗20~40μm,分散程度很小,稍扁,很直的是猪皮;纤维束长3~10mm,粗70~140μm,分散程度较小,较圆的是牛皮;纤维束长6mm以内,粗30~70μm,分散程度较大,稍扁,略卷曲的是山羊皮。 展开更多
关键词 胶原蛋白纤维束 粗细程度 分散程度 皮革材质鉴别
道路沥青面层厚度缺陷处理与验收分析 预览
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作者 夏波 潘霞 《建筑技术开发》 2019年第9期150-151,共2页
分析沥青面层不合格原因,结合沥青面层性能作用,提出缺陷处理与验收的质量保障措施,有效规避了道路沥青面层厚度缺陷,节约了返工费用,达到预期效果,从而为类似工程提供借鉴。
关键词 道路 沥青面层 厚度 缺陷处理 验收
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大脑中动脉CTA-MIP后处理参数的优化及初步研究 预览
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作者 陈明山 邢刚 《国际医学放射学杂志》 北大核心 2019年第1期26-31,共6页
目的应用CT血管成像(CTA)最大密度投影(MIP)的多平面重组(MPR)后处理技术分析大脑中动脉(MCA)分段显示与所选层面厚度及角度间的关系,确定MCA分段显示的优化参数。方法回顾性分析2014年6月—2016年6月因疑似MCA缺血行头颅CTA及数字减影... 目的应用CT血管成像(CTA)最大密度投影(MIP)的多平面重组(MPR)后处理技术分析大脑中动脉(MCA)分段显示与所选层面厚度及角度间的关系,确定MCA分段显示的优化参数。方法回顾性分析2014年6月—2016年6月因疑似MCA缺血行头颅CTA及数字减影血管造影(DSA)检查的100例病人(764处节段血管)资料,其中男60例,女40例,平均(64.3±10.7)岁。利用CTA容积再现(VR)平台,分别测量所有病例M1段、M2段、M2-5段的空间跨度及走行角度参数值并进行分组,随后在CTA-MIP-MPR平台,对MPR厚度和偏移角度的不同测试值进行验证,并对各个重组影像进行质量评分,确定各分段最优参数,并将优化CTA-MIP影像与DSA影像进行比较分析,评价其优化效果。多组间比较采用单因素方差分析,应用受试者操作特征(ROC)曲线评价优化CTA-MIP诊断血管狭窄的价值,CTA与DSA检查结果的一致性分析采用Kappa检验。结果在CTA-MIP中,MCA M1段最优化参数为冠状面、层厚15 mm、角度偏移0°,其影像质量评分为3.85±0.51,均高于其他组(均P<0.05);MCA M2段最优化参数为矢状面、层厚25 mm、角度偏移0°,其影像质量评分为3.36±0.53,均高于其他组(均P<0.05);M2-5段最优化参数为①低头冠状面、层厚35 mm、角度偏移35°;②外旋矢状面、层厚35 mm、轴转25°、矢转30°;2组影像质量评分分别为3.41±0.40、3.42±0.33,均高于其他组(均P<0.05)。优化CTA-MIP检查对血管狭窄的诊断敏感度、特异度、阳性预测值、阴性预测值、ROC曲线下面积分别为90.5%、97.7%、87.5%、98.3%、0.941。对于4种不同狭窄程度血管的诊断,优化CTA-MIP检查与DSA检查结果一致率为96.5%(κ=0.783,P<0.05)。结论基于优化的选层厚度及偏移角度,CTA-MIP分段显示能够清晰展示MCA各段管腔大小、走行及分支细节,与DSA有较高的一致性。 展开更多
关键词 大脑中动脉 CT血管成像 最大密度投影 角度 厚度 分段显示 参数优化
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Thickness evolution of graphite-based cathodes in the dual ion batteries via in operando optical observation 预览
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作者 Na Li Yaoda Xin +4 位作者 Haosen Chen Shuqiang Jiao Hanqing Jiang Wei-Li Song Daining Fang 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第2期122-128,共7页
Graphite has been currently considered as a promising cathode material in dual ion batteries(DIBs)due to its unique features of sp2 hybridized carbon and stacked two-dimensional layered structures.However,unexpected v... Graphite has been currently considered as a promising cathode material in dual ion batteries(DIBs)due to its unique features of sp2 hybridized carbon and stacked two-dimensional layered structures.However,unexpected volume/thickness changes in the graphite cathodes,induced by the intercalation/deintercalation of anions with large molecular size have been known to be a critical problem in designing DIB cells.To understand the volume/thickness changes in the DIB electrodes,in operando optical observing apparatus has been employed to observe the cross-section view of a graphite-based cathode upon cycles in the present work.The observation suggests that the cathode initially presented a huge irreversible thickness change(60%),and such thickness variation was prone to reduce and remain <20% in the following cycles.The results from both in operando observation and electrochemical characterizations collectively indicate that the greater thickness variation at initial cycle should be attributed to both anion intercalation into graphite-based cathodes and irreversible decomposition of chemical components in the DIB system.The method here highlights a universal route for fundamentally understanding the electrodes of huge volume variation. 展开更多
关键词 DUAL ion BATTERIES In OPERANDO optical observation GRAPHITE CATHODE Thickness EVOLUTION
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Estimated Average Glandular Dose for 1,828 Mammography Procedures in China: A Multicenter Study 预览
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作者 DU Xiang WANG Jin ZHU Bao Li 《生物医学与环境科学:英文版》 SCIE CAS CSCD 2019年第4期242-249,共8页
Objective To understand the distribution of the average glandular dose(AGD) in mammography by investigating 1,828 exposure parameters of 8 mammography machines in three cities, by using random sampling. Methods A surv... Objective To understand the distribution of the average glandular dose(AGD) in mammography by investigating 1,828 exposure parameters of 8 mammography machines in three cities, by using random sampling. Methods A survey of 8 mammography machines in three different cities, sampled using stratified random sampling methods, was performed, and 1,828 mammography exposure parameters were recorded. Incident air kerma(k) was measured by Quality-Assurance(QA) dosimeters, and AGD was calculated by series conversion coefficients based on a 3D detailed Monte Carlo breast model, published by Wang et al. Results The distribution of compressed breast thickness(CBT) fitted a normal distribution, while that of AGD fitted a skewed distribution. The mean value of CBT in a medio-lateral oblique(MLO) view was about 5.6% higher than that in the craniocaudal(CC) view, with significant statistical difference;mean value of AGD and CBT in the sample was 1.3 mGy and 4.6 cm, respectively. The AGD trended upward with increasing CBT, similar to the results of other researches. Conclusion The mean AGD and CBT levels in our study for mammography practice in China were 1.3 mGy and 4.6 cm, respectively. AGD is influenced by manufacturer-specific variation as machine response to CBT changes and target/filter combination. The present study can provide evidence for establishing a diagnostic reference level in China. 展开更多
关键词 Medical RADIATION MAMMOGRAPHY Compressed BREAST thickness AVERAGE GLANDULAR DOSE
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光学相干断层扫描分析对青少年近视眼的黄斑区视网膜血管密度及厚度价值的研究
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作者 宋婷婷 齐雪 《生命科学仪器》 2019年第2期59-63,共5页
目的:研究光学相干断层扫描分析(OCT)对青少年近视眼的黄斑区视网膜血管密度及厚度价值。方法:将自2016年3月开始至2018年3月时间段我院收治的近视眼青少年100例记作观察对象,将其按照近视度数的不同分成低度组44例,中度组40例,高度组16... 目的:研究光学相干断层扫描分析(OCT)对青少年近视眼的黄斑区视网膜血管密度及厚度价值。方法:将自2016年3月开始至2018年3月时间段我院收治的近视眼青少年100例记作观察对象,将其按照近视度数的不同分成低度组44例,中度组40例,高度组16例,比较各组患者的眼球参数水平。此外,对所有患者进行OCT检查,并对比各组患者的黄斑区表层及深层微血管密度,黄斑区不同部位的视网膜厚度,并作指标间的相关性分析。结果:三组患者的等效球镜度逐渐降低,而眼轴逐渐升高,各组差异有统计学意义(均P<0.05)。三组患者黄斑区表层及深层微血管密度水平均逐渐升高,各组差异有统计学意义(均P<0.05)。三组患者黄斑中心区、内环鼻侧部位的视网膜厚度逐渐升高,而内环上方、内环下方、内环鼻侧、内环颞侧部位的视网膜厚度逐渐降低,各组差异有统计学意义(均P<0.05)。经Pearson相关性分析,青少年近视眼度数与黄斑区视网膜表层、深层微血管密度以及黄斑中心区、内环鼻侧视网膜厚度呈正相关,而与内环上方、内环下方、内环颞侧、外环鼻侧视网膜厚度呈负相关(均P<0.05)。结论:随着青少年近视眼度数的不断增加,黄斑区视网膜血管密度及厚度随之变化。临床工作中可通过OCT及时发现黄斑区病变,从而为青少年近视眼的早期诊断、临床治疗提供指导作用。 展开更多
关键词 近视眼 光学相干断层扫描分析 视网膜 血管密度 厚度
浅谈浮法盖板玻璃的品质影响和化学增强强度 预览
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作者 高多军 岳凯 张晓春 《中国玻璃》 2019年第2期23-26,共4页
本文对浮法盖板玻璃的成形品质缺陷、透过率、厚度、翘度等指标对盖板玻璃的品质影响进行阐述,并针对盖板玻璃的化强强度、时间、温度等进行讨论。
关键词 盖板玻璃 成形缺陷 透光率 厚度 翘曲
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Impact of Thickness of Polymer Electrolyte Membrane and Gas Diffusion Layer on Temperature Distributions in Polymer Electrolyte Fuel Cell Operated at Temperature around 90℃ 预览
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作者 Akira Nishimura Yusuke Sato +4 位作者 Satoru Kamiya Tatsuya Okado Kouhei Yamamoto Masafumi Hirota Eric Hu 《能源与动力工程:英文版》 2019年第3期97-115,共19页
Polymer Electrolyte Fuel Cell(PEFC)is desired to be operated at temperature around 90℃ for stationary applications during the period from 2020 to 2025 in Japan.It can be expected thinner polymer electrolyte membrane(... Polymer Electrolyte Fuel Cell(PEFC)is desired to be operated at temperature around 90℃ for stationary applications during the period from 2020 to 2025 in Japan.It can be expected thinner polymer electrolyte membrane(PEM)and gas diffusion layer(GDL)would promote the power generation performance of PEFC at this temperature.The aim of this study is to understand the impact of thickness of PEM and GDL on the temperature profile of interface between PEM and catalyst layer at the cathode(i.e.,the reaction surface)in a single PEFC with an initial operation temperature(Tini).An 1D multi-plate heat transfer model based on temperature data of separator measured using thermograph in power generation process was developed to evaluate temperature of the reaction surface(Treact).This study investigated the effect of Tini,flow rate and relative humidity of supply gas on Treact distribution.The study finds that when using thin GDL,the even distribution of Treact – Tini is obtained irrespective of thickness of PEM,Tini and relative humidity conditions.Treact – Tini using Nafion 115 is higher than the other thin PEMs irrespective of Tini and relative humidity conditions.It can be concluded that the even temperature distribution could be achieved by using thin PEM and GDL. 展开更多
关键词 PEFC heat transfer model TEMPERATURE distribution operation TEMPERATURE AROUND 90℃ thickness of PEM and GDL RELATIVE humidity condition.
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