Since the discovery of carbon dots(CDs)in 2004,the unique photoluminescence phenomenon of CDs has attracted widespread attention.However,the molecular weight of CDs has not been adequately quantified at present,due to...Since the discovery of carbon dots(CDs)in 2004,the unique photoluminescence phenomenon of CDs has attracted widespread attention.However,the molecular weight of CDs has not been adequately quantified at present,due to CDs are atomically imprecise and their molecular weight distribution is broad.In this paper,a series of Pluronic-modified CDs were prepared and the structure of the CDs was briefly analyzed.Subsequently,a molecular weight measurement method based on colligative properties was developed,and the correction coefficient in the algorithm was briefly analyzed.The calculated molecular weight was applied to the determination of surface adsorption capacity.This work provided a method for averaging the molecular weight of atomically imprecise particulate materials,which is expected to provide new opportunities in related fields.展开更多
Students' thinking in physics learning has changed from junior high school to senior high school. However, the teaching method of physics in senior high school has not changed with the change of students' thin...Students' thinking in physics learning has changed from junior high school to senior high school. However, the teaching method of physics in senior high school has not changed with the change of students' thinking mode. As a result, students have difficulties in the process of acceptance and their grades have declined. With the development of curriculum reform, traditional teaching has not adapted to the transition requirements of junior high school. This paper applies the research methods of interview, observation and comparison to dissect students' learning behavior, teachers' teaching behavior, teaching materials and other aspects, trying to find out the reasons for the "gap" in physics classroom teaching in junior and senior high schools, and puts forward the solutions to the problem.展开更多
目的:探讨第二产程初期运用支撑式前倾跪位对全程实施分娩镇痛的初产妇分娩结局的影响。方法:按纳入排除方法将实施分娩镇痛的初产妇按完全随机方法分成观察组和对照组各95例。两组孕妇第一产程均采取自由体位。观察组第二产程初期采用...目的:探讨第二产程初期运用支撑式前倾跪位对全程实施分娩镇痛的初产妇分娩结局的影响。方法:按纳入排除方法将实施分娩镇痛的初产妇按完全随机方法分成观察组和对照组各95例。两组孕妇第一产程均采取自由体位。观察组第二产程初期采用支撑式前倾跪位,至胎先露为(S+4)时,改为膀胱截石位;对照组第二产程全程为膀胱截石位。两组产妇均使用常规手法接生,分析比较两组孕产妇间产程和分娩结局的差异。结果:观察组第二产程时间较对照组短(67.54±37.28 min vs.79.17±35.76 min,P<0.05),新生儿1 min Apgar评分高于对照组(9.97±0.67 vs.9.77±0.23,P<0.05)。二分类Logistic回归分析显示观察组阴道分娩率明显高于对照组(OR=8.644,95%CI=1.059-70.530),第二产程中胎心减速的发生率明显低于对照组(OR=0.253,95%CI=0.079-0.809)。结论:对于全程实施分娩镇痛的初产妇,在第二产程初期运用支撑式前倾跪位可以缩短第二产程,降低中转剖宫产率,提高阴道分娩成功率,改善新生儿评分。展开更多
针对SAR图像船舶检测任务在船舶组合和船舶融合场景下低检测精度的问题,提出了一种轻量化船舶检测算法——RGDET-Ship,有效提高了SAR图像在复杂场景下的船舶检测精度。该算法的创新点包括:①构建基于改进ResNet的基础主干网络,增强深浅...针对SAR图像船舶检测任务在船舶组合和船舶融合场景下低检测精度的问题,提出了一种轻量化船舶检测算法——RGDET-Ship,有效提高了SAR图像在复杂场景下的船舶检测精度。该算法的创新点包括:①构建基于改进ResNet的基础主干网络,增强深浅网络早特征融合,保留更丰富的有效特征图,并利用RegNet进行模型搜索得到一簇最优结构子网络RegNet and Early-Add(RGEA),实现模型的轻量化;②在FPN Neck基础上,结合EA-fusion策略设计出FPN and Early Add Fusion(FEAF)Neck网络,进一步加强深浅特征晚融合,提高中大船舶目标特征的提取;③通过细粒度分析改进RPN网络得到Two-RPN(TRPN)网络,提高模型的检测粒度和预测框准确性;④引入多任务损失函数——Cross Entropy Loss and Smooth L1 Loss(CE_S),包括分类任务和回归任务,进一步提升检测性能。通过在标准基准数据集SSDD上进行大量实验,验证了RGDET-Ship模型的有效性和健壮性。实验结果表明,相较于Faster RCNN和Cascade RCNN,RGDET-Ship在mAP_0.5:0.95上分别提升了5.6%和3.3%,在AR上分别提升了9.8%和7.6%。展开更多
文摘Since the discovery of carbon dots(CDs)in 2004,the unique photoluminescence phenomenon of CDs has attracted widespread attention.However,the molecular weight of CDs has not been adequately quantified at present,due to CDs are atomically imprecise and their molecular weight distribution is broad.In this paper,a series of Pluronic-modified CDs were prepared and the structure of the CDs was briefly analyzed.Subsequently,a molecular weight measurement method based on colligative properties was developed,and the correction coefficient in the algorithm was briefly analyzed.The calculated molecular weight was applied to the determination of surface adsorption capacity.This work provided a method for averaging the molecular weight of atomically imprecise particulate materials,which is expected to provide new opportunities in related fields.
文摘Students' thinking in physics learning has changed from junior high school to senior high school. However, the teaching method of physics in senior high school has not changed with the change of students' thinking mode. As a result, students have difficulties in the process of acceptance and their grades have declined. With the development of curriculum reform, traditional teaching has not adapted to the transition requirements of junior high school. This paper applies the research methods of interview, observation and comparison to dissect students' learning behavior, teachers' teaching behavior, teaching materials and other aspects, trying to find out the reasons for the "gap" in physics classroom teaching in junior and senior high schools, and puts forward the solutions to the problem.
文摘目的:探讨第二产程初期运用支撑式前倾跪位对全程实施分娩镇痛的初产妇分娩结局的影响。方法:按纳入排除方法将实施分娩镇痛的初产妇按完全随机方法分成观察组和对照组各95例。两组孕妇第一产程均采取自由体位。观察组第二产程初期采用支撑式前倾跪位,至胎先露为(S+4)时,改为膀胱截石位;对照组第二产程全程为膀胱截石位。两组产妇均使用常规手法接生,分析比较两组孕产妇间产程和分娩结局的差异。结果:观察组第二产程时间较对照组短(67.54±37.28 min vs.79.17±35.76 min,P<0.05),新生儿1 min Apgar评分高于对照组(9.97±0.67 vs.9.77±0.23,P<0.05)。二分类Logistic回归分析显示观察组阴道分娩率明显高于对照组(OR=8.644,95%CI=1.059-70.530),第二产程中胎心减速的发生率明显低于对照组(OR=0.253,95%CI=0.079-0.809)。结论:对于全程实施分娩镇痛的初产妇,在第二产程初期运用支撑式前倾跪位可以缩短第二产程,降低中转剖宫产率,提高阴道分娩成功率,改善新生儿评分。
文摘针对SAR图像船舶检测任务在船舶组合和船舶融合场景下低检测精度的问题,提出了一种轻量化船舶检测算法——RGDET-Ship,有效提高了SAR图像在复杂场景下的船舶检测精度。该算法的创新点包括:①构建基于改进ResNet的基础主干网络,增强深浅网络早特征融合,保留更丰富的有效特征图,并利用RegNet进行模型搜索得到一簇最优结构子网络RegNet and Early-Add(RGEA),实现模型的轻量化;②在FPN Neck基础上,结合EA-fusion策略设计出FPN and Early Add Fusion(FEAF)Neck网络,进一步加强深浅特征晚融合,提高中大船舶目标特征的提取;③通过细粒度分析改进RPN网络得到Two-RPN(TRPN)网络,提高模型的检测粒度和预测框准确性;④引入多任务损失函数——Cross Entropy Loss and Smooth L1 Loss(CE_S),包括分类任务和回归任务,进一步提升检测性能。通过在标准基准数据集SSDD上进行大量实验,验证了RGDET-Ship模型的有效性和健壮性。实验结果表明,相较于Faster RCNN和Cascade RCNN,RGDET-Ship在mAP_0.5:0.95上分别提升了5.6%和3.3%,在AR上分别提升了9.8%和7.6%。
文摘针对遥感影像复杂背景和小目标检测困难的问题,提出了一种基于多感知融合的检测算法YOLO-GT。为了提升特征图中小目标的特征信息,设计了包含3种感知机制的检测头Adaptive Scale-Aware Dynamic Head(ASADH);引入轻量级上采样算子Content-Aware ReAssembly of Features (CARAFE),解决语义信息丢失问题,提升特征金字塔网络性能;为进一步优化模型的训练速度和定位精度,采用了Wise-IoU作为损失函数。实验结果在DIOR数据集上显示,模型精度达90.4%,比原算法提高2.1%。这些改进有效提高了复杂背景下遥感影像小目标的检测性能。
