Graphene materials have excellent optical and electrical properties,and in recent years,significant achievements have been made in the chemical improvement and preparation of graphene.This article analyzes the progres...Graphene materials have excellent optical and electrical properties,and in recent years,significant achievements have been made in the chemical improvement and preparation of graphene.This article analyzes the progress in the chemical preparation,chemical modification,surface chemistry,and catalysis of graphene,in order to provide reference for relevant personnel.展开更多
AIM:To evaluate the detectability of gallbladder stones by dual-energy spectral computed tomography(CT) imaging.METHODS:Totally 217 patients with surgically confirmed gallbladder stones were retrospectively analyzed w...AIM:To evaluate the detectability of gallbladder stones by dual-energy spectral computed tomography(CT) imaging.METHODS:Totally 217 patients with surgically confirmed gallbladder stones were retrospectively analyzed who underwent single-source dual-energy CT scanning from August 2011 to December 2013. Polychromatic images were acquired. And post-processing software was used to reconstruct monochromatic(40 ke V and 140 ke V) images,and calcium-lipid pair-wise base substance was selected to acquire calcium base images and lipid base images. The above 5 groups of images were evaluated by two radiologists separately with 10-year experience in CT image reading. In the 5 groups of images,the cases in the positive group and negative group were counted and then the detection rate was calculated. The inter-observer agreement on the scoring results was analyzed by Kappa test,and the scoring results were analyzed by Wilcoxon test,with P < 0.05 indicating that the difference was statistically significant. The stone detection results of the 5 groups of images were analyzed by χ2 test.RESULTS:There was good inter-observer agreement(k = 0.772). In 217 patients with gallbladder stones,there was a statistically significant difference in stone visualization between spectral images(40 ke V,140 ke V,calcium base and lipid base images) and polychromatic images(P < 0.05). 40 ke V monochromatic images were better than 140 ke V monochromatic images(4.90 ± 0.35 vs 4.53 ± 1.15,P < 0.05),and calcium base images were superior to lipid base images(4.91 ± 0.43 vs 4.77 ± 0.63,P < 0.05),but there was no statisticallysignificant difference between 40 ke V monochromatic images and calcium base images(4.90 ± 0.35 vs 4.91 ± 0.43,P > 0.05). In 217 gallbladder stone patients,there were 21,3,28,5 and 12 negative stone cases in polychromatic images,40 ke V images,140 ke V images,calcium base images and lipid base images,respectively,and the differences among the five groups were statistically significant(P < 0.05).CONCLUSION:Monochromatic images and base substance images have a good clinical prospect in the iso-density stone detection.展开更多
为解决配电网中分布式电源(DG)高比例渗透引起的电压偏差问题,提高系统电压稳定性,提出一种DG并网逆变器和电压检测型有源滤波器(voltage detection based active power filter,VDAPF)参与电压治理的SVG优化配置策略。采用分区思想,提...为解决配电网中分布式电源(DG)高比例渗透引起的电压偏差问题,提高系统电压稳定性,提出一种DG并网逆变器和电压检测型有源滤波器(voltage detection based active power filter,VDAPF)参与电压治理的SVG优化配置策略。采用分区思想,提出基于社团理论的分区方法,选取各区域的主导治理节点作为SVG候选接入节点;建立SVG总投资成本最小和系统电压偏差治理效果最优的多目标SVG优化配置模型,并采用改进的遗传算法对配置模型进行求解;考虑DG并网逆变器和电压检测型APF剩余容量的不确定性,采用多场景分析技术构建一系列电压治理运行场景。以IEEE 33节点配电网结构为算例进行分析,验证了所提优化配置策略的有效性和合理性。展开更多
Alzheimer’s disease（AD）is a progressive cognitive disorder that develops predominantly in elderly patients and is characterized by cognitive impairments affecting memory,learning,and attention（Selkoe,2002）.
目的:探讨术前衰弱对老年心脏手术患者术后跌倒坠床发生率、认知功能和日常生活活动能力的影响。方法:选择我院2018年1月~2021年1月收治的271例拟行心脏手术的老年患者,按照术前是否合并衰弱情况,将患者分别纳入衰弱组、非衰弱组,对比...目的:探讨术前衰弱对老年心脏手术患者术后跌倒坠床发生率、认知功能和日常生活活动能力的影响。方法:选择我院2018年1月~2021年1月收治的271例拟行心脏手术的老年患者,按照术前是否合并衰弱情况,将患者分别纳入衰弱组、非衰弱组,对比两组患者术后跌倒坠床发生率、并发症发生率、住院时间及术前、术后认知功能和日常生活活动能力的变化。结果:271例患者中,共有78例(28.78%)符合衰弱判断。衰弱组术后跌倒坠床、并发症发生率高于非衰弱组,其住院时间较非衰弱组更长,差异有统计学意义(P<0.05)。两组患者术后7 d简易智力精神状态检查量表(MMSE)评分均较术前下降,衰弱组术后7 d MMSE评分低于非衰弱组,差异有统计学意义(P<0.05)。衰弱组术后认知功能障碍(POCD)发生率为11.54%(9/78),高于非衰弱组的1.04%(2/193),差异有统计学意义(P<0.05)。两组患者术后7 d基础性日常生活活动能力(BADL)及工具性日常生活活动能力(IADL)评分均较术前下降,衰弱组术后7 d BADL、IADL评分低于非衰弱组,差异有统计学意义(P<0.05)。结论:合并术前衰弱的老年患者较非衰弱患者心脏手术后跌倒坠床发生率、并发症发生率更高,认知功能、日常生活活动能力受影响越明显,且术后恢复速度更慢。展开更多
文摘Graphene materials have excellent optical and electrical properties,and in recent years,significant achievements have been made in the chemical improvement and preparation of graphene.This article analyzes the progress in the chemical preparation,chemical modification,surface chemistry,and catalysis of graphene,in order to provide reference for relevant personnel.
文摘AIM:To evaluate the detectability of gallbladder stones by dual-energy spectral computed tomography(CT) imaging.METHODS:Totally 217 patients with surgically confirmed gallbladder stones were retrospectively analyzed who underwent single-source dual-energy CT scanning from August 2011 to December 2013. Polychromatic images were acquired. And post-processing software was used to reconstruct monochromatic(40 ke V and 140 ke V) images,and calcium-lipid pair-wise base substance was selected to acquire calcium base images and lipid base images. The above 5 groups of images were evaluated by two radiologists separately with 10-year experience in CT image reading. In the 5 groups of images,the cases in the positive group and negative group were counted and then the detection rate was calculated. The inter-observer agreement on the scoring results was analyzed by Kappa test,and the scoring results were analyzed by Wilcoxon test,with P < 0.05 indicating that the difference was statistically significant. The stone detection results of the 5 groups of images were analyzed by χ2 test.RESULTS:There was good inter-observer agreement(k = 0.772). In 217 patients with gallbladder stones,there was a statistically significant difference in stone visualization between spectral images(40 ke V,140 ke V,calcium base and lipid base images) and polychromatic images(P < 0.05). 40 ke V monochromatic images were better than 140 ke V monochromatic images(4.90 ± 0.35 vs 4.53 ± 1.15,P < 0.05),and calcium base images were superior to lipid base images(4.91 ± 0.43 vs 4.77 ± 0.63,P < 0.05),but there was no statisticallysignificant difference between 40 ke V monochromatic images and calcium base images(4.90 ± 0.35 vs 4.91 ± 0.43,P > 0.05). In 217 gallbladder stone patients,there were 21,3,28,5 and 12 negative stone cases in polychromatic images,40 ke V images,140 ke V images,calcium base images and lipid base images,respectively,and the differences among the five groups were statistically significant(P < 0.05).CONCLUSION:Monochromatic images and base substance images have a good clinical prospect in the iso-density stone detection.
文摘为解决配电网中分布式电源(DG)高比例渗透引起的电压偏差问题,提高系统电压稳定性,提出一种DG并网逆变器和电压检测型有源滤波器(voltage detection based active power filter,VDAPF)参与电压治理的SVG优化配置策略。采用分区思想,提出基于社团理论的分区方法,选取各区域的主导治理节点作为SVG候选接入节点;建立SVG总投资成本最小和系统电压偏差治理效果最优的多目标SVG优化配置模型,并采用改进的遗传算法对配置模型进行求解;考虑DG并网逆变器和电压检测型APF剩余容量的不确定性,采用多场景分析技术构建一系列电压治理运行场景。以IEEE 33节点配电网结构为算例进行分析,验证了所提优化配置策略的有效性和合理性。
基金supported by a grant KAKENHI 15K06786the Center of Innovation Science and Technology based Radical Innovation and Entrepreneurship Program(COI STREAM)of the Ministry of Education,Culture,Sports,Science and Technology(MEXT),Japan
文摘Alzheimer’s disease（AD）is a progressive cognitive disorder that develops predominantly in elderly patients and is characterized by cognitive impairments affecting memory,learning,and attention（Selkoe,2002）.
文摘目的:探讨术前衰弱对老年心脏手术患者术后跌倒坠床发生率、认知功能和日常生活活动能力的影响。方法:选择我院2018年1月~2021年1月收治的271例拟行心脏手术的老年患者,按照术前是否合并衰弱情况,将患者分别纳入衰弱组、非衰弱组,对比两组患者术后跌倒坠床发生率、并发症发生率、住院时间及术前、术后认知功能和日常生活活动能力的变化。结果:271例患者中,共有78例(28.78%)符合衰弱判断。衰弱组术后跌倒坠床、并发症发生率高于非衰弱组,其住院时间较非衰弱组更长,差异有统计学意义(P<0.05)。两组患者术后7 d简易智力精神状态检查量表(MMSE)评分均较术前下降,衰弱组术后7 d MMSE评分低于非衰弱组,差异有统计学意义(P<0.05)。衰弱组术后认知功能障碍(POCD)发生率为11.54%(9/78),高于非衰弱组的1.04%(2/193),差异有统计学意义(P<0.05)。两组患者术后7 d基础性日常生活活动能力(BADL)及工具性日常生活活动能力(IADL)评分均较术前下降,衰弱组术后7 d BADL、IADL评分低于非衰弱组,差异有统计学意义(P<0.05)。结论:合并术前衰弱的老年患者较非衰弱患者心脏手术后跌倒坠床发生率、并发症发生率更高,认知功能、日常生活活动能力受影响越明显,且术后恢复速度更慢。
