The most significant changes of landscape in a certain period are landscape area changes and spatial changes of landscape patches.Based on transfer matrix and total amount change of landscape area,landscape space tran...The most significant changes of landscape in a certain period are landscape area changes and spatial changes of landscape patches.Based on transfer matrix and total amount change of landscape area,landscape space transfer index and landscape area change index were established,and then applied to analyze plain oasis and desert in Yutian County,Xinjiang Uyghur Nationality Autonomous Region,the results showed that landscape space transfer in this region was drastic,but total landscape area changed only slightly,thus space transfer index was much higher than area change index,which indicated that landscapes in arid area were given with particular spatial undulant features and sensitivity,while man-made landscapes(artificial oasis) are stable and expanding to some extent.With landscape space transfer index as the comprehensive indicator,space transfer intensity of landscape within a certain period can be demonstrated,which is favorable for the comparison of landscape change intensity among different types and within different periods,in addition,some macroscopic change features of landscapes can also be reflected by comprehensively analyzing landscape space transfer index and landscape area change index.展开更多
In this paper,using aδ-doping dual-channel structure and GaAs substrate,a real space transfer transistor(RSTT)is designed and fabricated successfully.It has the standardΛ-shaped negative resistance I-V characteristi...In this paper,using aδ-doping dual-channel structure and GaAs substrate,a real space transfer transistor(RSTT)is designed and fabricated successfully.It has the standardΛ-shaped negative resistance I-V characteristics as well as a level and smooth valley region that the conventional RSTT has.The negative resistance parameters can be varied by changing gate voltage(VGS).For example,the PVCR varies from 2.1 to 10.6 while VGS changes from 0.6 V to 1.0 V.The transconductance for IP(ΔIP=ΔVGS)is 0.3 mS.The parameters of VP,VV and threshold gate voltage(VT)for negative resistance characteristics arising are all smaller than the value reported in the literature.Therefore,this device is suitable for low dissipation power application.展开更多
The components of combustion chamber (cylinder head-cylinder liner-piston assembly-oil film) were taken as a coupled body.Based on the three-dimensional heat transfer numerical simulation of the coupled body,a coupled...The components of combustion chamber (cylinder head-cylinder liner-piston assembly-oil film) were taken as a coupled body.Based on the three-dimensional heat transfer numerical simulation of the coupled body,a coupled three-dimensional calculation model for in-cylinder working process and the combustion chamber components was built with domain decomposition and boundary coupled method,which implements the coupled three-dimensional simulation of in-cylinder working process and the combustion chamber components.The model was applied in the influence investigation of the space non-uniformity in heat transfer among combustion chamber components on the generation of in-cylinder emissions:NOx.The results showed that the heat transfer space non-uniformity of combustion chamber components directly influences the formation of in-cylinder NOx.The main area being influenced was the accessory area on the wall,while the influence on the generation of NOx in the central area couold be omitted.展开更多
目的观察基于MR-T2WI的深度迁移学习(deep transfer learning,DTL)特征、影像组学特征及临床特征构建的联合模型(列线图)在术前预测宫颈癌淋巴脉管间隙浸润(lymph vascular space invasion,LVSI)的价值。材料与方法回顾性分析178例经术...目的观察基于MR-T2WI的深度迁移学习(deep transfer learning,DTL)特征、影像组学特征及临床特征构建的联合模型(列线图)在术前预测宫颈癌淋巴脉管间隙浸润(lymph vascular space invasion,LVSI)的价值。材料与方法回顾性分析178例经术后病理证实为宫颈癌的患者病例,其中70例LVSI(+)、108例LVSI(-),按照8∶2划分为训练集[142例,54例LVSI(+)、88例LVSI(-)]和测试集[36例,16例LVSI(+)、20例LVSI(-)]。对临床因素行单因素logistic分析,筛选出LVSI(+)独立预测因素。使用DTL方法和传统影像组学方法提取矢状位T2WI图像中病灶的DTL特征和影像组学特征,构建DTL特征数据集、影像组学特征数据集和DTL特征与影像组学特征融合的数据集,分别以t检验、Pearson分析和最小绝对收缩和选择算子(least absolute shrinkage and selection operator,LASSO)回归对训练集各特征数据集进行特征降维,以其最佳者构建影像组学(radiomics,Rad)模型、DTL模型、融合模型(Rad+DTL模型),并筛选最佳影像组学模型;基于上述最佳影像组学模型评分与临床独立因子构建联合模型,并绘制列线图。以校准曲线评估模型校准度,以决策曲线分析评价模型的应用价值。结果淋巴结转移、粒细胞比率均为LVSI(+)的独立预测因子(P<0.05)。Rad+DTL模型为最佳影像组学模型。联合模型在训练集和测试集中的受试者工作特征曲线下面积(area under the curve,AUC)高于Rad+DTL模型(0.984 vs.0.966,P<0.05;0.912 vs.0.759,P=0.05)。联合模型的校准度较高,临床净收益更大。结论基于MR-T2WI的DTL特征、影像组学特征联合临床特征构建的联合模型可有效预测宫颈癌LVSI。展开更多
基金Supported by National Natural Science Foundation(40661002)Project of National Natural Science Youth Foundation(40701188)Highlevel Talents Initiation Project of Shihezi University(RCZX200693)~~
文摘The most significant changes of landscape in a certain period are landscape area changes and spatial changes of landscape patches.Based on transfer matrix and total amount change of landscape area,landscape space transfer index and landscape area change index were established,and then applied to analyze plain oasis and desert in Yutian County,Xinjiang Uyghur Nationality Autonomous Region,the results showed that landscape space transfer in this region was drastic,but total landscape area changed only slightly,thus space transfer index was much higher than area change index,which indicated that landscapes in arid area were given with particular spatial undulant features and sensitivity,while man-made landscapes(artificial oasis) are stable and expanding to some extent.With landscape space transfer index as the comprehensive indicator,space transfer intensity of landscape within a certain period can be demonstrated,which is favorable for the comparison of landscape change intensity among different types and within different periods,in addition,some macroscopic change features of landscapes can also be reflected by comprehensively analyzing landscape space transfer index and landscape area change index.
文摘In this paper,using aδ-doping dual-channel structure and GaAs substrate,a real space transfer transistor(RSTT)is designed and fabricated successfully.It has the standardΛ-shaped negative resistance I-V characteristics as well as a level and smooth valley region that the conventional RSTT has.The negative resistance parameters can be varied by changing gate voltage(VGS).For example,the PVCR varies from 2.1 to 10.6 while VGS changes from 0.6 V to 1.0 V.The transconductance for IP(ΔIP=ΔVGS)is 0.3 mS.The parameters of VP,VV and threshold gate voltage(VT)for negative resistance characteristics arising are all smaller than the value reported in the literature.Therefore,this device is suitable for low dissipation power application.
基金Sponsored by the National Natural Science Foundation of China (Grant No. 50576008,50876016,and 51006015)
文摘The components of combustion chamber (cylinder head-cylinder liner-piston assembly-oil film) were taken as a coupled body.Based on the three-dimensional heat transfer numerical simulation of the coupled body,a coupled three-dimensional calculation model for in-cylinder working process and the combustion chamber components was built with domain decomposition and boundary coupled method,which implements the coupled three-dimensional simulation of in-cylinder working process and the combustion chamber components.The model was applied in the influence investigation of the space non-uniformity in heat transfer among combustion chamber components on the generation of in-cylinder emissions:NOx.The results showed that the heat transfer space non-uniformity of combustion chamber components directly influences the formation of in-cylinder NOx.The main area being influenced was the accessory area on the wall,while the influence on the generation of NOx in the central area couold be omitted.
文摘目的观察基于MR-T2WI的深度迁移学习(deep transfer learning,DTL)特征、影像组学特征及临床特征构建的联合模型(列线图)在术前预测宫颈癌淋巴脉管间隙浸润(lymph vascular space invasion,LVSI)的价值。材料与方法回顾性分析178例经术后病理证实为宫颈癌的患者病例,其中70例LVSI(+)、108例LVSI(-),按照8∶2划分为训练集[142例,54例LVSI(+)、88例LVSI(-)]和测试集[36例,16例LVSI(+)、20例LVSI(-)]。对临床因素行单因素logistic分析,筛选出LVSI(+)独立预测因素。使用DTL方法和传统影像组学方法提取矢状位T2WI图像中病灶的DTL特征和影像组学特征,构建DTL特征数据集、影像组学特征数据集和DTL特征与影像组学特征融合的数据集,分别以t检验、Pearson分析和最小绝对收缩和选择算子(least absolute shrinkage and selection operator,LASSO)回归对训练集各特征数据集进行特征降维,以其最佳者构建影像组学(radiomics,Rad)模型、DTL模型、融合模型(Rad+DTL模型),并筛选最佳影像组学模型;基于上述最佳影像组学模型评分与临床独立因子构建联合模型,并绘制列线图。以校准曲线评估模型校准度,以决策曲线分析评价模型的应用价值。结果淋巴结转移、粒细胞比率均为LVSI(+)的独立预测因子(P<0.05)。Rad+DTL模型为最佳影像组学模型。联合模型在训练集和测试集中的受试者工作特征曲线下面积(area under the curve,AUC)高于Rad+DTL模型(0.984 vs.0.966,P<0.05;0.912 vs.0.759,P=0.05)。联合模型的校准度较高,临床净收益更大。结论基于MR-T2WI的DTL特征、影像组学特征联合临床特征构建的联合模型可有效预测宫颈癌LVSI。
