期刊文献+
共找到8篇文章
< 1 >
每页显示 20 50 100
不平衡因子对药芯焊丝CO_2气体保护焊焊缝金属韧度的影响 被引量:2
1
作者 桂赤斌 周红兵 +1 位作者 喻朝飞 杜晓琪 《焊接学报》 EI CAS CSCD 北大核心 2007年第1期46-48,共3页
研究了由氮化物形成元素Al,Ti等控制的不平衡因子B对低合金药芯焊丝CO2气体保护焊缝金属韧度的作用。结果表明,在药芯具有氧化性的条件下,不平衡因子B对焊缝金属韧度的作用仍然明显。并且相比实心焊丝CO2气体保护焊而言,不平衡因子B的... 研究了由氮化物形成元素Al,Ti等控制的不平衡因子B对低合金药芯焊丝CO2气体保护焊缝金属韧度的作用。结果表明,在药芯具有氧化性的条件下,不平衡因子B对焊缝金属韧度的作用仍然明显。并且相比实心焊丝CO2气体保护焊而言,不平衡因子B的最佳值增大了。分析表明,药芯焊丝自身的氧化性是不平衡因子B增大的原因。在不平衡因子B由小增加到最佳值的过程中,焊缝金属组织由粒状贝氏体+板条铁素体逐渐向以夹杂物为核心的针状铁素体组织发展,由此其韧度逐渐改善;而当不平衡因子B超过最佳值较多时,过剩的氮化物形成元素进入铁素体固溶而导致脆化。 展开更多
关键词 药芯焊丝 CO2气体保护焊 韧度 不平衡因子
下载PDF
基于不平衡数据分类的一种平衡模糊支持向量机 被引量:6
2
作者 秦传东 刘三阳 张市芳 《计算机科学》 CSCD 北大核心 2012年第6期188-190,212,共4页
鉴于不平衡数据集中类不平衡比较大的分类问题,利用样本点的特性建立类不平衡调节因子和模糊隶属度,提出了平衡模糊支持向量机。首先计算样本协方差矩阵,求得类不平衡调节因子,然后计算各样本点的模糊隶属度,得到各样本对分类超平面的... 鉴于不平衡数据集中类不平衡比较大的分类问题,利用样本点的特性建立类不平衡调节因子和模糊隶属度,提出了平衡模糊支持向量机。首先计算样本协方差矩阵,求得类不平衡调节因子,然后计算各样本点的模糊隶属度,得到各样本对分类超平面的贡献率。类平衡调节因子和模糊隶属度同时对分类器的误差项产生影响。结果表明,这种平衡模糊支持向量机对类不平衡比较大的分类问题具有很好的分类效果。 展开更多
关键词 支持向量数据域描述 模糊隶属度 模糊支持向量机 平衡模糊支持向量机 不平衡因子
下载PDF
不对称输电线功率损失计算方法的研究
3
作者 苑薇薇 《东北电力技术》 1998年第10期27-29,共3页
研究了不对称输电线功率损失的计算方法,提出采用电流复数不平衡因子计算不对称输电线的功率损失,定义了电流复数不平衡因子,且复数不平衡因子由幅值和幅角两部分组成。经理论分析,推导出利用电流复数不平衡因子计算不对称输电线功... 研究了不对称输电线功率损失的计算方法,提出采用电流复数不平衡因子计算不对称输电线的功率损失,定义了电流复数不平衡因子,且复数不平衡因子由幅值和幅角两部分组成。经理论分析,推导出利用电流复数不平衡因子计算不对称输电线功率损失的计算公式。 展开更多
关键词 不对称 输电线 功率损失 电流复数 不平衡因子
下载PDF
基于IBFO算法的配电变压器最佳相位组合
4
作者 张岚 王献军 +2 位作者 丁博 王坤 张哲 《微型电脑应用》 2022年第9期102-106,共5页
为了通过变压器相位重排达到降低系统损耗的目的,通过对接入配电变压器的用户进行调查,并从用户信息系统(CIS)和配电数据库系统(DAS)中采集各用户的负载及其模式,将24个间隔内的母线损耗最小化作为目标函数,提出了一种改进细菌觅食优化(... 为了通过变压器相位重排达到降低系统损耗的目的,通过对接入配电变压器的用户进行调查,并从用户信息系统(CIS)和配电数据库系统(DAS)中采集各用户的负载及其模式,将24个间隔内的母线损耗最小化作为目标函数,提出了一种改进细菌觅食优化(IBFO)算法求解配电变压器最佳相位组合的方法。通过三相潮流计算程序,采用等效电流注入法(ECI)求解配电系统的母线损耗和系统不平衡度。研究结果有助于操作人员正确选择配电变压器的相位安装,并改善母线电压分布。 展开更多
关键词 不平衡因子 分配系统 细菌觅食优化 电力系统
下载PDF
矿用刮板输送机负载特性分析 被引量:3
5
作者 张国梁 《现代矿业》 CAS 2017年第10期144-145,147,共3页
对矿用刮板输送机在不同工况下的运行状态进行了分析,并从刮板输送机的启动特性、功率不平衡影响因子等方面讨论了其负载特性。在对电动机的传动系统和机械特性研究的基础上,重点探讨了启动难和过载的原因,供相关研究参考。
关键词 刮板输送机 负载特性 启动特性 功率不平衡影响因子
下载PDF
Genomic imbalances in esophageal carcinoma cell lines involve Wnt pathway genes 被引量:7
6
作者 Jacqueline Brown Hannelie Bothma +1 位作者 Robin Veale Pascale Willem 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第24期2909-2923,共15页
AIM: To identify molecular markers shared across South African esophageal squamous cell carcinoma (ESCC) cell lines using o/togenetics, fluorescence in situ hybridization (FISH) and single nucleotide polymorphism... AIM: To identify molecular markers shared across South African esophageal squamous cell carcinoma (ESCC) cell lines using o/togenetics, fluorescence in situ hybridization (FISH) and single nucleotide polymorphism (SNP) array copy number analysis. METHODS: We used conventional cytogenetics, FISH, and multicolor FISH to characterize the chromosomal rearrangements of five ESCC cell lines established in South Africa. The whole genome copy number profile was established from 250K SNP arrays, and data was analyzed with the CNAT 4.0 and GISTIC software. tions involved the following chromosomal regions and genes: 11q13.3 (CCND1, FGF3, FGF4, FGF19, MYEOV), 8q24.21(C-MYC, FAM84B), 11q22.1-q22.3 (B[RC2, BIRC3), 5p15.2 (CTNND2), 3qll.2-q12.2 (MINA) and 18p11.32 (TYMS, YES1). The significant deletions included 1p31.2-p31.1 (CTH, GADD45a, DIRAS3), 2q22.1 (LRPIB), 3p12.1-p14.2 (FHIT), 4q22.1-q32.1 (CASP6, SMAD1), 8p23.2-q11.1 (BNIP3L) and 18q21.1-q21.2 (SMAD4, DCC). The 3p11.2 translocation breakpoint was shared across four cell lines, supporting a role for genes involved at this site, in particular, the EPHA3 gene which has previously been reported to be deleted in ESCC.CONCLUSION: The finding that a significant number of genes that were amplified (FGF3, FGF4, FGF19, CCND1 and C-MYC) or deleted (SFRP2 gene) are involved in the Wnt and fibroblast growth factor signaling pathways, suggests that these pathways may be activated in these cell lines. 展开更多
关键词 ESOPHAGUS CANCER Single nucleotide polymorphism arrays Fluorescent in situ hybridization
下载PDF
Unequal Development and Territorial Competitiveness of Network Economy
7
作者 郭健全 汤兵勇 《Journal of Donghua University(English Edition)》 EI CAS 2004年第1期89-95,共7页
The territorial consideration is enclosed in the development of network economy and e-Business, and there is no departure of the cultivation of e-Business from the establishment of territorial competitiveness. The tra... The territorial consideration is enclosed in the development of network economy and e-Business, and there is no departure of the cultivation of e-Business from the establishment of territorial competitiveness. The traditional theory of the territorial competitiveness has come across a serious impact from the Internet. So the development of Intemet infrastructures and institutional environment would be something new to the theory of territorial competitiveness in the Internet era. 展开更多
关键词 network economy territorial competitiveness internet infrastructures internet institutional environment
下载PDF
Fracture analysis of rock mass based on 3-D nonlinear Finite Element Method 被引量:8
8
作者 LIU YaoRu CHANG Qiang +2 位作者 YANG Qiang WANG ChuanQi GUAN FuHai 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第3期556-564,共9页
Traditional fracture analysis is based on fracture mechanics and damage mechanics. They focus on the propagation of the fracture. However, their propagation criterions are not easily applied in practice and the curren... Traditional fracture analysis is based on fracture mechanics and damage mechanics. They focus on the propagation of the fracture. However, their propagation criterions are not easily applied in practice and the current analysis is limited in planar problem. This paper presents a new theory that the occurrence of the unbalanced force (derived from the Deformation Reinforcement Theory) could be the criterion of the initiation of the fracture, and the distribution area and propagation of the unbalanced force could be the indication of the fracture propagation direction. By aggregate analysis with Stress Intensity Factor (SIF) criterion, the unbalanced force actually is the opposite external load that is the SIF difference incurred between the external loads and permitted by the structure. Numerical simulation and physical experiments on pre-fracture cuboid rock specimens proved that the occurrence of the unbalanced force could be the initiation of the fracture. Mesh size dependence was also considered by analysis of different mesh size finite element gravity dam models. Furthermore, the theory was applied to the feasibility analysis of the Baihetan arch dam together with physical experiments in order to evaluate the fracture propagation of dam heel. The results show that it is an effective way to use unbalanced force to analyze the fracture initiation and propagation when performing 3-dimensional nonlinear FEM calculation. 展开更多
关键词 fracture analysis rock mass unbalanced force plastic complementary energy norm nonlinear finite element method
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部