期刊文献+
共找到10篇文章
< 1 >
每页显示 20 50 100
动态有向超图中限制不交B-路算法设计
1
作者 米文燕 张淑蓉 《应用数学进展》 2022年第4期1857-1869,共13页
超图在现实生活中有很重要的应用价值,比如信息传递、货物运输、商品配送等问题都可以归约到超图中建立数学模型并设计优化算法。而网络环境是会随时间发生连续动态变化的,故本文主要研究动态超图中的连通性问题。同时,由于大规模网络... 超图在现实生活中有很重要的应用价值,比如信息传递、货物运输、商品配送等问题都可以归约到超图中建立数学模型并设计优化算法。而网络环境是会随时间发生连续动态变化的,故本文主要研究动态超图中的连通性问题。同时,由于大规模网络中故障的发生是不可避免的,而且是极具破坏性的,所以,提高网络的生存性能,保证网络的容错性有很重要的研究价值。设计不交超路径是提高网络容错性的主要解决方案。由于超路中B-路有很好的结构性质和广泛的应用背景,因此,本文在时变超图网络中考虑满足时间限制的不交B-路构建问题。目前由于动态网络研究的复杂性,连续时间动态网络背景的处理方法大多是采用时间离散化转换为静态网络去求近似解,本文考虑当给定起始时刻时,在时间范围[0,Τ]内每条超弧的延迟函数为连续时间动态函数的情况下,针对不交B-路问题给出最优解的求解算法,并证明算法的正确性及运算复杂度。 展开更多
关键词 有向超图 容错性 动态网络 b-路 不交
下载PDF
B-稳压电路在DAM机中的作用与应用
2
作者 周洪江 《数字传媒研究》 2024年第3期73-76,共4页
本文介绍了正泰DAM10kW-Ⅱ型全固态中波广播发射机B-稳压电路在DAM机中的作用与应用,对B-稳压电路进行分析,为设备维护人员提供参考。
关键词 b-稳压电 音频+直流 调制 功放模块
下载PDF
DAM-10kW中波发射机B-电源电路原理和作用 被引量:2
3
作者 张永胜 《西部广播电视》 2017年第16期239-239,共1页
随着科学技术的进步,DAM中波发射机已经得到广泛应用。B-电源在DAM-10kW中波发射机中发挥着重要作用,能够有效对发射机的噪声输出进行控制,B-电源设置的合理性影响DAM-10kW中波发射机的运行效率。本文对DAM-10KW中波发射机B-电源电路原... 随着科学技术的进步,DAM中波发射机已经得到广泛应用。B-电源在DAM-10kW中波发射机中发挥着重要作用,能够有效对发射机的噪声输出进行控制,B-电源设置的合理性影响DAM-10kW中波发射机的运行效率。本文对DAM-10KW中波发射机B-电源电路原理进行分析,并就其作用进行探讨。 展开更多
关键词 DAM-10kW 中波发射机 b-电源电 原理 作用
下载PDF
Symmetric alteration of four knots of B-spline and NURBS surfaces
4
作者 LI Ya-juan WANG Guo-zhao 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第6期1084-1087,共4页
Modifying the knots of a B-spline curve, the shape of the curve will be changed. In this paper, we present the effect of the symmetric alteration of four knots of the B-spline and the NURBS surfaces, i.e., symmetrical... Modifying the knots of a B-spline curve, the shape of the curve will be changed. In this paper, we present the effect of the symmetric alteration of four knots of the B-spline and the NURBS surfaces, i.e., symmetrical alteration of the knots of surface, the extended paths of points of the surface will converge to a point which should be expressed with several control points. This theory can be used in the constrained shape modification of B-spline and NURBS surfaces. 展开更多
关键词 b-spline surface NURBS surface Knot modification PATH
下载PDF
B-spline curve-based routing in ad hoc networks
5
作者 黄林 《High Technology Letters》 EI CAS 2012年第4期428-432,共5页
Routing algorithms capable of providing quality of service (QoS) will play an important role in future communication networks. For the trajectory-based routing ( TBR), An effective method of en- coding trajectorie... Routing algorithms capable of providing quality of service (QoS) will play an important role in future communication networks. For the trajectory-based routing ( TBR), An effective method of en- coding trajectories into packets is proposed. The method uses a B-spline curve, which provides a lot of flexibility. The simulation results show that the performance of the proposed algorithms is im- proved significantly compared with the existing algorithm. 展开更多
关键词 ROUTING quality of service (QoS) b-spline curve
下载PDF
Modulation of B-cell receptor and microenvironment signaling by a guanine exchange factor in B-cell malignancies
6
作者 Wei Liao Sanjai Sharma 《Cancer Biology & Medicine》 SCIE CAS CSCD 2016年第2期277-285,共9页
Objective: Chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL) cells over-express a guanine exchange factor (GEF), Rasgrf-1. This GEF increases active Ras as it catalyzes the removal of GDP from R... Objective: Chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL) cells over-express a guanine exchange factor (GEF), Rasgrf-1. This GEF increases active Ras as it catalyzes the removal of GDP from Ras so that GTP can bind and activate Ras. This study aims to study the mechanism of action of Rasgrf-1 in B-cell malignancies. Methods: N-terminus truncated Rasgrf-1 variants have a higher GEF activity as compared to the full-length transcript therefore a MCL cell line with stable over-expression of truncated Rasgrf-1 was established. The B-cell receptor (BCR) and chemokine signaling pathways were compared in the Rasgrf-I over-expressing and a control transfected cell line. Results: Cells over-expressing truncated form of Rasgrf-1 have a higher proliferative rate as compared to control transfected cells. BCR was activated by lower concentrations of anti-IgM antibody in Rasgrf-1 over-expressing cells as compared to control cells indicating that these cells are more sensitive to BCR signaling. BCR signaling also phosphorylates Rasgrf-1 that further increases its GEF function and amplifies BCR signaling. This activation of Rasgrf-1 in over-expressing cells resulted in a higher expression of phospho-ERK, AKT, BTK and PKC-alpha as compared to control cells. Besides BCR, Rasgrf-1 over-expressing cells were also more sensitive to microenvironment stimuli as determined by resistance to apoptosis, chemotaxis and ERK pathway activation. Conclusions: This GEF protein sensitizes B-cells to BCR and chemokine mediated signaling and also upregulates a number of other signaling pathways which promotes growth and survival of these cells. 展开更多
关键词 b-ceU malignancies mantle cell lymphoma chronic lymphocytic leukemia (CLL) b-cell receptor guanine exchange factorRasgrf- 1 ERK pathway
下载PDF
INCREASING BREAKDOWN VOLTAGE OF LDMOST USING BURIED LAYER
7
作者 Han Lei Ye Xingning Chen Xingbi (Institute of Microelectronics, University of Electrical Science and Technology of China,, Chengdu 610054) 《Journal of Electronics(China)》 2003年第1期29-32,共4页
A new LDMOST structure, named B-LDMOST that has a buried layer under the drain is proposed. The buried layer is not connected to the drift region, so it can optimize the vertical field distribution and increase breakd... A new LDMOST structure, named B-LDMOST that has a buried layer under the drain is proposed. The buried layer is not connected to the drift region, so it can optimize the vertical field distribution and increase breakdown voltage. The analysis and the simulated results show that B-LDMOST can increase breakdown voltage, with almost negligible influence on the other parameters such as on-resistance, switching time, and so on. 展开更多
关键词 b-LDMOST Buried layer Breakdown voltage Ou-resistance Switching time
下载PDF
2.5 Gb/s 16∶1 MUX IC Design with CMOS
8
作者 ZHANGCheng-an SONGQi-feng WANGZhi-gong 《Semiconductor Photonics and Technology》 CAS 2004年第4期233-236,共4页
A low-power and high-speed 16:1 MUX IC designed for Optical fiber communication based on TSMC 0.25 μm CMOS technology is represented. A tree-type architecture was utilized. The output data bit rate is 2.5 Gb/s at inp... A low-power and high-speed 16:1 MUX IC designed for Optical fiber communication based on TSMC 0.25 μm CMOS technology is represented. A tree-type architecture was utilized. The output data bit rate is 2.5 Gb/s at input clock rate of 1.25 GHz. The simulation results show that the output signal has peak-to-peak amplitude of 400 mV, the power dissipation is less than 200 mW and the power dissipation of core circuit is less than 20 mW at the 2.5 Gb/s standard bit rate and supply voltage of 2.5 V. The chip area is (1.8) mm2. 展开更多
关键词 MUX CMOS integrated circuit Optical fiber communication
下载PDF
The role of Tbx2 in pancreatic cancers and its regulation by Wnt/β-catenin signaling
9
作者 Ping Chen Dean Tian Mei Liu 《The Chinese-German Journal of Clinical Oncology》 CAS 2008年第7期404-409,共6页
Objective: To investigate the expression of Tbx2 protein in pancreatic cancer tissues and its molecular regulation mechanism by Wnt/β-catenin signaling. Methods: 49 pancreatic cancer and 13 non-cancer tissue specimen... Objective: To investigate the expression of Tbx2 protein in pancreatic cancer tissues and its molecular regulation mechanism by Wnt/β-catenin signaling. Methods: 49 pancreatic cancer and 13 non-cancer tissue specimens were obtained and examined the expression of Tbx2, and the correlation between the expression of Tbx2 and clinicopathological parameters was analyzed. The immunohistochemistry, immunocytochemistry, RT-PCR and Western blot assay methods were used to detect the changes of expression levels of β-catenin and Tbx2. Results: Tbx2 was amplified in 34 of 49 pancreatic cancers, and in 13 non-cancer tissues, only one sample amplified. The further study demonstrated that Tbx2 had a significant positive correlation with tumor differentiation degree and clinical stage, but it did not relate to the sex, age and the disease region. Inhibi-tion of β-catenin degradation through the treatment of pancreatic cancer cells SW1990 with different concentrations of lithium chloride indicated that accumulation of β-catenin was sufficient to induce TBX2 expression. Conclusion: TBX2 gene plays an important role in the occurrence and development of pancreatic cancer and the accumulation of β-catenin contributes to the expression of TBX2. The Wnt/β-catenin signaling pathway participates the regulation of TBX2 in pancreatic cancer cells. 展开更多
关键词 pancreatic cancer TBX2 Β-CATENIN
下载PDF
Porcine placental peptides improve neuroblast proliferation and differentiation via enhancement of TrkB and BDNF levels in D-glatacose-induced mouse aging model
10
作者 Xu Quan Caihong Gu +5 位作者 Feng Yan Yaoyao Gao Lin Chen Rong Wei Bingchun Yan Rong Hul 《Journal of Chinese Pharmaceutical Sciences》 CAS CSCD 2019年第10期739-748,共10页
Aging affects the nervous system as well as other organs.In our study,we aimed to study the pharmacological effects and mechanism of porcine placental peptides(PPP)in aging process,and to observe the changes of neurob... Aging affects the nervous system as well as other organs.In our study,we aimed to study the pharmacological effects and mechanism of porcine placental peptides(PPP)in aging process,and to observe the changes of neuroblast proliferation and differentiation as well as partial gene expression in hippocampus of D-galactose-induced aged mouse.Based on the analysis of experimental results,it was confirmed that PPP significantly improved neurobalst proliferation and differentiation in the mouse hippocampal DG by ki-67 and DCX immunohistochemistry.This result showed that PPP had anti-aging effects on D-galactoseinduced aging mouse model.Moreover,we observed up-regulated expressions of BDNF and TrkB proteins and down-regulated expressions of Caspase 3,8,and 9 proteins in the PPP-treated mouse hippocampus.Therefore,our results showed that PPP obviously improved neuroblast proliferation and differentiation,and its anti-aging effect might berelated to down-regulation of apoptosis-related proteins,including Caspase 3,8,and 9,via BDNF/TrkB pathway.Our findings provided valuable evidence for its applications in the health and medicine sectors. 展开更多
关键词 Porcine placenta peptide ANTI-AGING Neuroblast proliferation and differentiation Apoptosis-related proteins BDNF/TrkB pathway
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部